{"gene":"S100A8","run_date":"2026-06-10T07:46:28","timeline":{"discoveries":[{"year":2016,"finding":"Crystal structures of calcium- and zinc-loaded human S100A8 reveal that S100A8 binds two zinc ions per homodimer through symmetrical all-His tetrahedral coordination sites (His4 motif), and that zinc stabilizes S100A8 tetramerization by tightening the dimer-dimer interface; calcium induces the S100A8 tetramer.","method":"X-ray crystallography (two crystal forms), structural analysis","journal":"BMC structural biology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — crystal structures with two independent crystal forms, direct structural validation of zinc-binding mode and tetramer interface","pmids":["27251136"],"is_preprint":false},{"year":2012,"finding":"Ca2+ and Zn2+-binding properties of S100A8 regulate its conformational state and oligomerization, including self-assembly into homodimers, heterodimers with S100A9, tetramers, and higher oligomers including amyloid fibrils; these transitions are linked to distinct functional states.","method":"Biophysical characterization, in vitro assembly assays, structural analysis","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal biophysical methods reported across labs, but primarily review-level synthesis","pmids":["22489132"],"is_preprint":false},{"year":2008,"finding":"S100A8 undergoes S-nitrosylation at its single Cys residue (Cys34 in human); S-nitrosylated S100A8 (S100A8-SNO) transnitrosylates hemoglobin (acting as an NO transporter), suppresses mast cell activation, and inhibits leukocyte adhesion and extravasation in vivo; the Cys→Ala mutant is not S-nitrosylated, confirming the Cys residue is required.","method":"HPLC/mass spectrometry, biotin-switch assay, site-directed mutagenesis (Cys-to-Ala), intravital microscopy, in vitro mast cell assay","journal":"Journal of immunology","confidence":"High","confidence_rationale":"Tier 1 / Strong — multiple orthogonal methods (MS, biotin-switch, mutagenesis, in vivo imaging) in single rigorous study establishing the PTM and its functional consequence","pmids":["18832721"],"is_preprint":false},{"year":2011,"finding":"S100A8 suppresses IgE-crosslinking-induced mast cell degranulation and cytokine production (IL-6, IL-4, GM-CSF) via inhibition of intracellular ROS, reducing downstream LAT and ERK/MAPK phosphorylation; this activity requires the Cys41 residue, as the Cys41-Ala mutant lacks this anti-inflammatory activity. In vivo, S100A8 reduced eosinophil chemoattractant production and eosinophil infiltration in acute murine asthma.","method":"In vitro mast cell assay, site-directed mutagenesis, phosphorylation analysis, murine acute asthma model","journal":"Antioxidants & redox signaling","confidence":"High","confidence_rationale":"Tier 2 / Strong — loss-of-function mutagenesis combined with in vitro and in vivo phenotypic readouts, multiple cytokine endpoints","pmids":["21142608"],"is_preprint":false},{"year":2014,"finding":"S100A8 induces IL-10 expression specifically in airway epithelial cells in vivo; this requires the Cys42 residue (Cys42-Ala mutant fails to induce IL-10 and is less immunosuppressive). S100A8 suppresses LPS-induced acute lung injury by reducing NF-κB activation via an IκBα/Akt pathway and downmodulating oxidative stress pathways.","method":"Intranasal administration in BALB/c mice, Cys-to-Ala mutagenesis, gene expression time-course, LPS-induced ALI model","journal":"Journal of immunology","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vivo model with mutagenesis demonstrating Cys-dependence of IL-10 induction and pathway identification","pmids":["24532576"],"is_preprint":false},{"year":2016,"finding":"Neuroplastin-β (NPTN-β) was identified as a novel receptor for S100A8. Upon S100A8 binding, neuroplastin-β recruits GRB2 and activates ERK, resulting in keratinocyte proliferation. Neuroplastin-β and EMMPRIN (an S100A9 receptor) form a functional heterodimeric receptor complex on keratinocyte surfaces, and knockdown of both receptors suppressed cell proliferation and proinflammatory cytokine induction.","method":"Receptor identification, co-immunoprecipitation, knockdown experiments, transgenic mouse model, signaling pathway analysis","journal":"The Journal of investigative dermatology","confidence":"High","confidence_rationale":"Tier 2 / Strong — receptor identification with multiple validation approaches (Co-IP, KD, transgenic mouse), orthogonal signaling readouts","pmids":["27388991"],"is_preprint":false},{"year":2019,"finding":"S100A8/A9 binding to neuroplastin-β (NPTNβ) in lung cancer cells activates TRAF2/RAS signaling, leading to downstream activation of NFIA, NFIB, and SPDEF transcription factors, promoting anchorage-independent growth, motility, and invasiveness.","method":"In vitro cancer cell assays, in vivo xenograft model, mechanistic signaling pathway analysis","journal":"Molecular carcinogenesis","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — single lab, multiple functional assays and pathway mapping, in vivo validation","pmids":["30720226"],"is_preprint":false},{"year":2022,"finding":"S100A8/A9 binds GPIbα on platelets to drive formation of procoagulant (phosphatidylserine-positive) platelets, with a supporting role for CD36. This was established using recombinant GPIbα ectodomain as a blocking agent, platelets from a Bernard-Soulier syndrome patient lacking GPIb-IX-V, and platelets from mice deficient in the extracellular domain of GPIbα.","method":"Platelet functional assays, recombinant receptor blocking, patient platelets (Bernard-Soulier), GPIbα-knockout mouse platelets, flow cytometry, perfusion assays","journal":"Blood","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal genetic and biochemical approaches (human genetic disease, mouse KO, recombinant blocking) confirming GPIbα as the receptor","pmids":["36026606"],"is_preprint":false},{"year":2022,"finding":"S100A8/S100A9 dimers activate TLR4, but extracellular calcium induces tetramer formation that prevents TLR4 binding. S100A8/A9 tetramers instead interact with CD69 on monocytes to dampen monocyte adhesion, migration, traction force generation, and immigration in vivo; thus the quaternary structure determines receptor selectivity and opposing inflammatory effects.","method":"In vitro monocyte functional assays (adhesion, migration, traction force), in vivo cutaneous granuloma model and contact dermatitis model, receptor blocking with anti-CD69","journal":"Advanced science","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal in vitro and in vivo assays distinguishing dimer vs. tetramer receptor binding with functional consequence","pmids":["36310133"],"is_preprint":false},{"year":2020,"finding":"Neutrophil-released S100A8 and S100A9 bind TLR4 on naïve neutrophils, priming the NLRP3 inflammasome and promoting IL-1β secretion, which then stimulates IL-1R1 on hematopoietic stem and progenitor cells in bone marrow to drive granulopoiesis after myocardial infarction.","method":"Mouse LAD-ligation MI model, flow cytometry, genetic knockout (S100A8/A9-deficient), pharmacological disruption, transcriptome analysis","journal":"Circulation","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic and pharmacological strategies defining the pathway sequentially (S100A8/A9 → TLR4 → NLRP3 → IL-1β → HSPC granulopoiesis)","pmids":["31941367"],"is_preprint":false},{"year":2015,"finding":"S100A8/A9 interacts with RAGE on NK cells to enhance NKG2D ligand-mediated IFN-γ production; RAGE antagonistic peptide and anti-RAGE antibody blocked S100A8/A9-induced NK cell IFN-γ production, and RAGE inhibitor FPS-ZM1 enhanced tumor growth in vivo.","method":"Co-culture assays, RAGE inhibitors/blocking antibodies, in vivo tumor model with pharmacological RAGE inhibition","journal":"Journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — receptor identified by pharmacological blocking (multiple inhibitors), supported by in vivo model; single lab","pmids":["25911757"],"is_preprint":false},{"year":2005,"finding":"S100A8 acts as an avid scavenger of reactive oxygen species including hypochlorite; in neutrophils and monocytes it is more sensitive to hypochlorite oxidation than albumin or LDL. S100A8-S100A9 complexes in atherosclerotic plaque undergo hypochlorite-mediated cross-linking. S100A8 in macrophages regulates NADPH-oxidase activity and fatty acid transport as part of the S100A8-S100A9 heterodimer.","method":"Oxidation sensitivity assays, immunoaffinity, redox biochemistry, human plaque characterization","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct biochemical assays showing oxidant-scavenging activity, single lab with multiple methods","pmids":["16216873"],"is_preprint":false},{"year":2001,"finding":"IL-10 synergizes with LPS and IFN-γ to increase S100A8 mRNA (≥9-fold) and secreted S100A8 protein (~4-fold) in macrophages via increased gene transcription; the effect is dependent on de novo protein synthesis and maps to a 178-bp promoter region containing CCAAT-enhancing binding protein motifs. IL-10 induction is mechanistically distinct from STAT-pathway-dependent IL-10 target genes.","method":"Luciferase promoter reporter assay, blocking antibodies (endogenous IL-10), mRNA stability analysis, pharmacological pathway dissection","journal":"Journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — promoter mapping and transcriptional analysis with multiple pathway inhibitors, single lab","pmids":["11342660"],"is_preprint":false},{"year":2000,"finding":"IFN-γ and TNF regulate S100A8 mRNA induction in murine macrophages through distinct kinetics; S100A8 gene induction is modulated by intracellular Ca2+ mobilization, protein kinase C, and MAPK pathways. Luciferase reporter assays confirmed LPS and IFN induce S100A8 gene transcription.","method":"Luciferase reporter assay, mRNA stability analysis, pharmacological inhibitors of signaling pathways (PKC, MAPK, Ca2+)","journal":"Journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reporter assay and pharmacological dissection identify transcriptional regulation pathways, single lab","pmids":["10779802"],"is_preprint":false},{"year":2005,"finding":"Glucocorticoids amplify LPS-induced S100A8 expression in macrophages, fibroblasts, and endothelial cells by increasing both gene transcription and mRNA half-life; this requires new protein synthesis, IL-10, cyclooxygenase-2 pathway products, and both ERK1/2 and p38 MAPK. Protein kinase A positively and PKC negatively regulate glucocorticoid enhancement. A NF1 motif at -58 bp is a candidate mediator. GCs also increase constitutive S100A8/A9 in human monocytes.","method":"Luciferase promoter reporter assay, gel shift/EMSA, pharmacological pathway inhibitors, mRNA stability assays","journal":"Journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple methods including promoter reporters and EMSA; single lab","pmids":["15699168"],"is_preprint":false},{"year":2005,"finding":"FGF-2 (enhanced by heparin) and IL-1β are distinct inducers of S100A8 in fibroblasts acting through different promoter elements; induction is partially dependent on the MAPK pathway and requires new protein synthesis. TGF-β suppresses FGF-2/heparin-induced S100A8, possibly via decreased mRNA stability. S100A9 is not co-induced with S100A8 in fibroblasts under any tested condition.","method":"Real-time RT-PCR, promoter analysis, pharmacological MAPK inhibition, TGF-β suppression assay","journal":"The FEBS journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — promoter element mapping and pathway inhibitors; single lab","pmids":["15943814"],"is_preprint":false},{"year":2013,"finding":"TNFα and IL-17A synergistically induce S100A8 mRNA and protein in human keratinocytes via a p38 MAPK-dependent mechanism; this was demonstrated by promoter luciferase reporter assay and p38 MAPK inhibitor blocking studies.","method":"qRT-PCR, luciferase reporter assay, p38 MAPK inhibitor","journal":"Experimental dermatology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reporter assay and pharmacological inhibition; single lab","pmids":["23800059"],"is_preprint":false},{"year":2022,"finding":"The transcription factor C/EBPδ is a central regulator of S100a8 (and S100a9) expression; C/EBPδ-dependent JMJD3-mediated demethylation of H3K27me3 at S100a8/S100a9 promoters is required for their expression. C/EBPδ KO mice show decreased S100A8/A9 and reduced neutrophil recruitment in acute lung inflammation.","method":"Genome-wide CRISPR/Cas9 KO screen, C/EBPδ KO mouse model, ChIP, chromatin accessibility analysis, promoter binding assays","journal":"eLife","confidence":"High","confidence_rationale":"Tier 1 / Strong — unbiased genome-wide CRISPR screen, in vivo genetic validation (KO mouse), and chromatin/epigenetic mechanism (H3K27me3 demethylation) confirmed by ChIP","pmids":["35543413"],"is_preprint":false},{"year":2012,"finding":"Hypoxia and HIF-1α increase S100A8 expression in prostate epithelial cells; functional hypoxia response elements (HREs) within the S100A8 promoter were identified by luciferase reporter assays, and direct HIF-1α binding to the S100A8 promoter was confirmed by chromatin immunoprecipitation.","method":"Promoter luciferase reporter assay, chromatin immunoprecipitation (ChIP), HIF-1α overexpression","journal":"International journal of cancer","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP and functional promoter assay in one study; single lab","pmids":["22505354"],"is_preprint":false},{"year":2021,"finding":"S100A8 and S100A9 are recruited to promoters and enhancers in a model of breast cellular transformation and interact with transcription factors in nuclear extracts, activating transcription when artificially recruited to a target promoter; nuclear-specific expression of S100A8/A9 promotes oncogenic transcription and enhances breast transformation.","method":"ChIP-seq, nuclear extract co-immunoprecipitation, artificial recruitment (tethering) to target promoter, nuclear-specific expression constructs","journal":"Science advances","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (ChIP-seq, Co-IP, artificial recruitment, functional transformation assay) in single study","pmids":["33523865"],"is_preprint":false},{"year":2015,"finding":"S100A8 promotes anaplastic thyroid carcinoma (ATC) cell proliferation through interaction with RAGE, which activates p38, ERK1/2, and JNK signaling pathways in tumor cells; S100A8 knockdown in ATC cells reduced tumor growth and lung metastasis in orthotopic mouse models.","method":"RNAi-mediated stable knockdown, bioluminescent in vivo imaging, orthotopic mouse models, signaling pathway analysis","journal":"The Journal of clinical endocrinology and metabolism","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo loss-of-function with defined receptor (RAGE) and signaling readouts; single lab","pmids":["25423568"],"is_preprint":false},{"year":2015,"finding":"S100A8 promotes colorectal tumorigenesis by activating Id3 (inhibitor of differentiation 3) downstream; S100A8 regulates colon cancer cell cycle and proliferation by inducing Id3 expression while inhibiting p21. Id3 expression is regulated by Smad5, which is directly phosphorylated by Akt1, establishing an S100A8→Akt1→Smad5→Id3 axis.","method":"Gene expression profiling, immunohistochemistry, proliferation/invasion assays, in vivo nude mouse metastasis model, signaling pathway analysis","journal":"International journal of cancer","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — pathway placement by functional assays in vitro and in vivo; single lab","pmids":["26135667"],"is_preprint":false},{"year":2020,"finding":"S100A8 significantly induces PD-L1 expression in monocytes/macrophages (but not tumor cells) through TLR4 receptor engagement and multiple inflammation-related signaling pathways; S100A8 modulates histone modification of the PD-L1 promoter in monocytes/macrophages. S100A8-pretreated macrophages had immunosuppressive function and attenuated anti-tumor CTL activity.","method":"TLR4 blocking, pharmacological inhibitors, promoter chromatin analysis (histone modification), co-culture CTL assays, in vivo tumor model","journal":"Journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — receptor (TLR4) and epigenetic mechanism identified with multiple methods; single lab","pmids":["32198140"],"is_preprint":false},{"year":2023,"finding":"MANF (mesencephalic astrocyte-derived neurotrophic factor) binds S100A8 to competitively block S100A8/A9 heterodimer formation, thereby inhibiting S100A8/A9-mediated TLR4-NF-κB signaling activation in macrophages. This was demonstrated by co-immunoprecipitation of MANF with S100A8.","method":"Co-immunoprecipitation (CO-IP), S100A8/A9 heterodimer formation assay, TLR4-NF-κB pathway analysis, genetic knockout mouse model","journal":"Acta pharmaceutica Sinica. B","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — CO-IP establishes direct protein-protein interaction; downstream signaling and in vivo validation; single lab","pmids":["37799387"],"is_preprint":false},{"year":2022,"finding":"S100A8 deficiency promotes epithelial-to-mesenchymal transition (EMT) in renal tubular epithelial cells during diabetic nephropathy through the TLR4/NF-κB signaling pathway; high S100A8/A9 expression activates TLR4/NF-κB to promote EMT and renal interstitial fibrosis. CO-IP assay confirmed that compound AB38b inhibits EMT by interfering with S100A8/A9 expression/interaction.","method":"RNA silencing, overexpression lentiviral constructs, TLR4/NF-κB pathway analysis, CO-IP, in vivo diabetic mouse model","journal":"Metabolism: clinical and experimental","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss/gain of function with defined pathway (TLR4/NF-κB → EMT); single lab","pmids":["36521551"],"is_preprint":false},{"year":2019,"finding":"S100A8 facilitates cholangiocarcinoma metastasis by activating the TLR4/NF-κB signaling pathway, which upregulates VEGF expression in CCA cells; this promotes vascular endothelial cell migration. Both in vitro and in vivo experiments confirmed that S100A8 overexpression enhanced, while knockdown attenuated, migration and metastasis.","method":"In vitro migration assays, in vivo xenograft model, TLR4/NF-κB pathway analysis, VEGF expression assays","journal":"International journal of oncology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — defined receptor-pathway axis (TLR4/NF-κB/VEGF) with in vitro and in vivo loss/gain of function; single lab","pmids":["31746424"],"is_preprint":false},{"year":2009,"finding":"Mrp8 (S100A8) and Mrp14 (S100A9) are endogenous TLR4 agonists that contribute to neuroinflammation after focal cerebral ischemia; Mrp14-deficient mice (which also lack Mrp8 protein) showed significantly reduced lesion volumes, less brain swelling, and reduced macrophage/microglia infiltration after transient focal ischemia.","method":"Mrp14 knockout mouse model, focal cerebral ischemia/reperfusion (1 h LAD ligation), lesion volume measurement, immunohistochemistry","journal":"Biochimica et biophysica acta","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic loss-of-function with defined phenotypic readout and pathway (TLR4); single lab","pmids":["19835955"],"is_preprint":false},{"year":2015,"finding":"S100A8/A9 deficiency results in impaired upregulation of CD11b on neutrophils during chronic tuberculosis infection, which mediates neutrophil accumulation; S100A8/A9-deficient mice show improved Mycobacterium tuberculosis control specifically during chronic (not acute) TB.","method":"S100A8/A9-deficient mouse model, CD11b expression analysis, neutrophil depletion, flow cytometry","journal":"The Journal of clinical investigation","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic loss-of-function with mechanism (CD11b regulation) identified; single lab","pmids":["32134742"],"is_preprint":false},{"year":2015,"finding":"S100A8 is rapidly and significantly increased in mature adipocytes during high-fat/high-sucrose diet, and acts as a chemoattractant for macrophages; recombinant S100A8 stimulated chemotactic migration of macrophages in vitro and in vivo and induced proinflammatory molecules (TNF-α and CCL2) in both macrophages and adipocytes. Anti-S100A8 antibody suppressed early macrophage mobilization in adipose tissue and ameliorated diet-induced insulin resistance.","method":"Intravital multiphoton imaging (LysM-EGFP transgenic mice), recombinant S100A8 chemotaxis assays, antibody neutralization in vivo","journal":"Proceedings of the National Academy of Sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct in vivo imaging combined with functional neutralization; single lab","pmids":["25848057"],"is_preprint":false},{"year":2015,"finding":"Secretion of S100A8/A9 from neutrophils is dependent on production of reactive oxygen species (ROS) and requires K+ efflux through ATP-sensitive K+ channels; particulate stimuli (MSU crystals, nanoparticles) and microbe-derived molecules (zymosan, HKCA) trigger secretion, while chemotactic fMLP does not induce S100A8/A9 secretion.","method":"Human neutrophil stimulation assays, ROS inhibitors, K+ channel blockers, ELISA for secreted S100 proteins","journal":"Journal of immunology research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — pharmacological dissection of secretion mechanism with multiple stimuli tested; single lab","pmids":["27057553"],"is_preprint":false},{"year":2011,"finding":"IL-1 receptor (IL-1R) signaling in oral keratinocytes, triggered by IL-1α released from Listeria-infected cells, increases S100A8/A9 gene expression in a paracrine manner; S100A8/A9 expression is required for IL-1α-mediated resistance to Listeria invasion, as shRNA knockdown of S100A8/A9 abrogated this protection.","method":"Conditioned medium transfer, IL-1R antagonist blocking, shRNA knockdown of S100A8/A9, intracellular bacterial invasion assay","journal":"Mucosal immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — receptor blocking and gene knockdown establish causal relationship; single lab","pmids":["22031183"],"is_preprint":false},{"year":2023,"finding":"Ponatinib (tyrosine kinase inhibitor) activates the S100A8/A9-TLR4-NLRP3-IL-1β signaling pathway in cardiac and systemic myeloid cells, leading to myocardial inflammation and dysfunction; specific inhibitors of S100A9 (paquinimod), NLRP3 (CY-09), or broad immunosuppression with dexamethasone nearly abolished ponatinib-induced cardiac dysfunction.","method":"RNA sequencing (unbiased), in vitro and in vivo pharmacological inhibition, multiple mouse models with cardiovascular comorbidities","journal":"Circulation research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — pathway defined by unbiased transcriptomics and multiple pharmacological interventions; single lab","pmids":["36625265"],"is_preprint":false},{"year":2014,"finding":"S100A8 and S100A9 homodimers (but not their heterodimeric complex) significantly upregulate chondrocyte ADAMTS1, ADAMTS4, ADAMTS5, MMP1, MMP3, and MMP13 gene expression, while decreasing collagen II and aggrecan mRNA, suggesting distinct functions of homodimer vs. heterodimer forms.","method":"qRT-PCR of primary ovine articular chondrocytes treated with recombinant homodimer vs. heterodimer forms","journal":"Arthritis research & therapy","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — single method (qRT-PCR) in a clean comparative experimental design; single lab but clear structural specificity","pmids":["20105291"],"is_preprint":false},{"year":2021,"finding":"IL-17A and IL-17F strongly induce S100A8 and S100A9 expression during early maturation stages of primary keratinocytes; S100A9-deficient keratinocytes show no significant role for S100A8/A9 in their own maturation or inflammatory response, and keratinocytes are not target cells for the proinflammatory effects of S100A8/A9.","method":"Primary S100A9-/- keratinocyte cultures, cytokine stimulation, imiquimod murine psoriasis model, transcriptome analysis","journal":"Frontiers in immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic KO model and primary cells; defines IL-17 as upstream inducer; single lab","pmids":["33643287"],"is_preprint":false},{"year":2024,"finding":"Cancer-cell-derived S100A8 binds CD147 receptor on cancer-associated fibroblasts (CAFs) and triggers the intracellular RhoA-ROCK-MLC2-MRTF-A signaling pathway, inducing CAF polarization and leading to chemoresistance in esophageal squamous-cell carcinoma; blocking the S100A8-CD147 pathway improved chemotherapy efficiency.","method":"Patient-derived xenografts (PDX), receptor identification (CD147), signaling pathway analysis (RhoA-ROCK-MLC2-MRTF-A), CAF co-culture and functional assays","journal":"Cell reports. Medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — receptor identified with functional pathway validation and in vivo PDX model; single lab","pmids":["38776909"],"is_preprint":false}],"current_model":"S100A8 is a calcium- and zinc-binding alarmin that functions as a homodimer or heterodimer with S100A9, with quaternary structure (dimer vs. Ca2+-induced tetramer) determining receptor selectivity: dimers activate TLR4 to promote inflammation, while tetramers bind CD69 to dampen monocyte activity; extracellularly, S100A8 also signals through RAGE (activating ERK in keratinocytes/tumor cells), GPIbα (driving procoagulant platelet formation), neuroplastin-β (activating TRAF2/RAS/ERK signaling), and CD147 (activating RhoA-ROCK in fibroblasts); S100A8 undergoes S-nitrosylation at its single Cys residue to acquire anti-inflammatory NO-transport and mast cell-suppressing properties, and its transcription is regulated by C/EBPδ-dependent H3K27me3 demethylation, as well as by IL-10/LPS, glucocorticoids, FGF-2/IL-1β, IL-17A/F, and HIF-1α acting on defined promoter elements; intracellularly, S100A8/A9 can also translocate to the nucleus to act as a transcriptional co-activator during oncogenic transformation."},"narrative":{"mechanistic_narrative":"S100A8 is a calcium- and zinc-binding alarmin whose conformational state — homodimer, S100A9 heterodimer, or Ca2+/Zn2+-induced tetramer — dictates which receptor it engages and therefore whether it drives or dampens inflammation [PMID:27251136, PMID:22489132, PMID:36310133]. Crystallographic analysis shows that S100A8 binds two zinc ions per homodimer through all-His tetrahedral sites, with zinc and calcium tightening the dimer-dimer interface to favor tetramerization [PMID:27251136]. This quaternary switch is functionally decisive: S100A8/A9 dimers activate TLR4, whereas Ca2+-induced tetramers cannot bind TLR4 and instead engage CD69 on monocytes to suppress adhesion, migration, and recruitment [PMID:36310133]. Through TLR4, secreted S100A8/A9 acts as an endogenous agonist that primes the NLRP3 inflammasome and IL-1β secretion, driving granulopoiesis after myocardial infarction, neuroinflammation after cerebral ischemia, and myeloid-cell-mediated cardiac dysfunction [PMID:31941367, PMID:19835955, PMID:36625265]. Beyond TLR4, S100A8 signals through a panel of receptors with cell-type-specific outputs: RAGE to activate ERK/p38/JNK in tumor cells and IFN-γ in NK cells [PMID:25911757, PMID:25423568], neuroplastin-β (partnered with EMMPRIN) to recruit GRB2 and activate ERK or TRAF2/RAS for keratinocyte and cancer-cell proliferation [PMID:27388991, PMID:30720226], GPIbα to drive procoagulant platelet formation [PMID:36026606], and CD147 to activate RhoA-ROCK signaling in cancer-associated fibroblasts [PMID:38776909]. S100A8 also has redox-dependent roles, scavenging reactive oxygen species including hypochlorite [PMID:16216873] and undergoing S-nitrosylation at its single cysteine to acquire NO-transport, mast-cell-suppressing, and anti-inflammatory activity that requires this Cys residue [PMID:18832721, PMID:21142608, PMID:24532576]. Intracellularly, S100A8/A9 can localize to the nucleus, bind transcription factors, and act as a transcriptional co-activator that promotes oncogenic transformation [PMID:33523865]. Its transcription is controlled by C/EBPδ-directed JMJD3-mediated H3K27me3 demethylation at the S100a8/a9 promoters and by inflammatory and hormonal inputs including IL-10/LPS, glucocorticoids, FGF-2/IL-1β, IL-17A/F, and HIF-1α acting through defined promoter elements [PMID:35543413, PMID:11342660, PMID:15699168, PMID:15943814, PMID:23800059, PMID:22505354].","teleology":[{"year":2008,"claim":"Established that S100A8 carries a redox-active single cysteine that can be S-nitrosylated, converting it into an NO transporter and anti-inflammatory mediator, defining a post-translational switch on alarmin function.","evidence":"HPLC/MS, biotin-switch assay, Cys-to-Ala mutagenesis, and intravital microscopy in vivo","pmids":["18832721"],"confidence":"High","gaps":["Did not define which receptors mediate the anti-inflammatory effects of S100A8-SNO","Physiological source of NO for in vivo S-nitrosylation not established"]},{"year":2011,"claim":"Showed the cysteine residue is mechanistically required for S100A8 to suppress mast cell degranulation via ROS inhibition, linking the redox-active Cys to an intracellular signaling output.","evidence":"In vitro mast cell assays, Cys-to-Ala mutagenesis, phosphorylation analysis, and murine acute asthma model","pmids":["21142608"],"confidence":"High","gaps":["Mechanism by which extracellular S100A8 accesses intracellular ROS not defined","Receptor mediating mast cell entry/signaling unidentified"]},{"year":2014,"claim":"Extended the Cys-dependent anti-inflammatory program to airway epithelium, where S100A8 induces IL-10 and suppresses NF-κB via IkBα/Akt.","evidence":"Intranasal administration in mice, Cys-to-Ala mutagenesis, and LPS-induced acute lung injury model","pmids":["24532576"],"confidence":"High","gaps":["Receptor transducing the IL-10-inducing signal not identified","Reconciliation with TLR4-driven proinflammatory roles not addressed"]},{"year":2016,"claim":"Resolved the structural basis for metal-dependent oligomerization, showing zinc binds via all-His sites to stabilize the tetramer interface and calcium induces tetramer formation — the structural foundation for state-dependent function.","evidence":"X-ray crystallography of Ca2+/Zn2+-loaded S100A8 in two crystal forms","pmids":["27251136"],"confidence":"High","gaps":["Structures do not show receptor-bound complexes","Did not directly link a given oligomer to a specific receptor"]},{"year":2016,"claim":"Identified neuroplastin-β as an S100A8 receptor that, with EMMPRIN, forms a heterodimeric receptor recruiting GRB2 to drive ERK and keratinocyte proliferation, defining a non-TLR4 signaling axis.","evidence":"Receptor identification, co-immunoprecipitation, knockdown, and transgenic mouse model","pmids":["27388991"],"confidence":"High","gaps":["Which oligomeric state binds neuroplastin-β not defined","Stoichiometry of the NPTNβ/EMMPRIN receptor complex unresolved"]},{"year":2020,"claim":"Defined a sequential TLR4-NLRP3-IL-1β cascade by which neutrophil-released S100A8/A9 amplifies emergency granulopoiesis after myocardial infarction.","evidence":"Mouse MI model, S100A8/A9 knockout, pharmacological disruption, and transcriptome analysis","pmids":["31941367"],"confidence":"High","gaps":["Did not address oligomeric state required for TLR4 priming","Contribution of S100A8 homodimer versus heterodimer not separated"]},{"year":2022,"claim":"Demonstrated that quaternary structure determines receptor selectivity — Ca2+-induced tetramers lose TLR4 binding and instead engage CD69 to suppress monocytes — unifying the opposing pro- and anti-inflammatory roles under one structural switch.","evidence":"Monocyte functional assays, anti-CD69 blocking, and in vivo granuloma and contact dermatitis models","pmids":["36310133"],"confidence":"High","gaps":["Did not co-resolve tetramer-CD69 structure","In vivo balance between dimer and tetramer pools under physiological Ca2+ not quantified"]},{"year":2022,"claim":"Identified the GPIbα receptor on platelets as an S100A8/A9 target driving procoagulant platelet formation, extending alarmin signaling into hemostasis.","evidence":"Recombinant GPIbα blocking, Bernard-Soulier patient platelets, and GPIbα-knockout mouse platelets","pmids":["36026606"],"confidence":"High","gaps":["Precise S100A8/A9 binding site on GPIbα not mapped","Role of CD36 cofactor mechanistically incomplete"]},{"year":2022,"claim":"Placed C/EBPδ as a central transcriptional driver of S100a8/a9, acting through JMJD3-mediated H3K27me3 demethylation, revealing an epigenetic mechanism controlling alarmin expression.","evidence":"Genome-wide CRISPR/Cas9 screen, C/EBPδ knockout mouse, and ChIP/chromatin accessibility analysis","pmids":["35543413"],"confidence":"High","gaps":["Stimulus-specific recruitment of C/EBPδ to the locus not fully resolved","Integration with other inducers (glucocorticoids, IL-17) not addressed"]},{"year":2021,"claim":"Revealed an intracellular nuclear role in which S100A8/A9 are recruited to promoters/enhancers and act as transcriptional co-activators promoting oncogenic transformation, distinct from extracellular receptor signaling.","evidence":"ChIP-seq, nuclear extract co-IP, artificial tethering, and breast transformation assays","pmids":["33523865"],"confidence":"High","gaps":["Direct DNA-binding versus transcription-factor-tethered recruitment not fully distinguished","Mechanism of nuclear import not defined"]},{"year":2024,"claim":"Defined CD147 on cancer-associated fibroblasts as a further S100A8 receptor driving RhoA-ROCK signaling and chemoresistance, broadening the receptor repertoire into the tumor stroma.","evidence":"Patient-derived xenografts, receptor identification, and RhoA-ROCK-MLC2-MRTF-A pathway analysis","pmids":["38776909"],"confidence":"Medium","gaps":["Single lab; reciprocal validation of CD147 binding limited","Oligomeric state binding CD147 not defined"]},{"year":null,"claim":"How the multiple receptors (TLR4, CD69, RAGE, neuroplastin-β, GPIbα, CD147) are selected by S100A8's metal-dependent oligomeric and redox states in any given tissue context remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unified map linking specific oligomers/PTMs to each receptor in vivo","Relative contributions of homodimer, heterodimer, and tetramer pools in physiological versus disease settings unquantified"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0048018","term_label":"receptor ligand activity","supporting_discovery_ids":[5,7,8,10,34]},{"term_id":"GO:0016209","term_label":"antioxidant activity","supporting_discovery_ids":[2,11]},{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[19]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[2]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[8]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[3,11]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[19]},{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[28,29]}],"pathway":[{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[8,9,26,27]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[5,6,10,34]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[20,21,24,25,31]},{"term_id":"R-HSA-109582","term_label":"Hemostasis","supporting_discovery_ids":[7]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[17,19]}],"complexes":["S100A8/S100A9 heterodimer/tetramer"],"partners":["S100A9","TLR4","RAGE","NPTN (NEUROPLASTIN-Β)","GP1BA","CD69","CD147","MANF"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P05109","full_name":"Protein S100-A8","aliases":["Calgranulin-A","Calprotectin L1L subunit","Cystic fibrosis antigen","CFAG","Leukocyte L1 complex light chain","Migration inhibitory factor-related protein 8","MRP-8","p8","S100 calcium-binding protein A8","Urinary stone protein band A"],"length_aa":93,"mass_kda":10.8,"function":"S100A8 is a calcium- and zinc-binding protein which plays a prominent role in the regulation of inflammatory processes and immune response. It can induce neutrophil chemotaxis and adhesion. Predominantly found as calprotectin (S100A8/A9) which has a wide plethora of intra- and extracellular functions. The intracellular functions include: facilitating leukocyte arachidonic acid trafficking and metabolism, modulation of the tubulin-dependent cytoskeleton during migration of phagocytes and activation of the neutrophilic NADPH-oxidase. Also participates in regulatory T-cell differentiation together with CD69 (PubMed:26296369). Activates NADPH-oxidase by facilitating the enzyme complex assembly at the cell membrane, transferring arachidonic acid, an essential cofactor, to the enzyme complex and S100A8 contributes to the enzyme assembly by directly binding to NCF2/P67PHOX. The extracellular functions involve pro-inflammatory, antimicrobial, oxidant-scavenging and apoptosis-inducing activities. Its pro-inflammatory activity includes recruitment of leukocytes, promotion of cytokine and chemokine production, and regulation of leukocyte adhesion and migration. Acts as an alarmin or a danger associated molecular pattern (DAMP) molecule and stimulates innate immune cells via binding to pattern recognition receptors such as Toll-like receptor 4 (TLR4) and receptor for advanced glycation endproducts (AGER). Binding to TLR4 and AGER activates the MAP-kinase and NF-kappa-B signaling pathways resulting in the amplification of the pro-inflammatory cascade. Has antimicrobial activity towards bacteria and fungi and exerts its antimicrobial activity probably via chelation of Zn(2+) which is essential for microbial growth. Can induce cell death via autophagy and apoptosis and this occurs through the cross-talk of mitochondria and lysosomes via reactive oxygen species (ROS) and the process involves BNIP3. Can regulate neutrophil number and apoptosis by an anti-apoptotic effect; regulates cell survival via ITGAM/ITGB and TLR4 and a signaling mechanism involving MEK-ERK. Its role as an oxidant scavenger has a protective role in preventing exaggerated tissue damage by scavenging oxidants. Can act as a potent amplifier of inflammation in autoimmunity as well as in cancer development and tumor spread. The iNOS-S100A8/A9 transnitrosylase complex directs selective inflammatory stimulus-dependent S-nitrosylation of GAPDH and probably multiple targets such as ANXA5, EZR, MSN and VIM by recognizing a [IL]-x-C-x-x-[DE] motif; S100A8 seems to contribute to S-nitrosylation site selectivity (Microbial infection) Upon infection by human coronavirus SARS-CoV-2, may induce expansion of aberrant immature neutrophils in a TLR4-dependent manner","subcellular_location":"Secreted; Cytoplasm; Cytoplasm, cytoskeleton; Cell membrane","url":"https://www.uniprot.org/uniprotkb/P05109/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/S100A8","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/S100A8","total_profiled":1310},"omim":[{"mim_id":"621210","title":"PU.1 (SPI1)-INDUCED REGULATOR OF S100A8 AND S100A9 ALARMIN TRANSCRIPTION 1, NONCODING; PIRAT1","url":"https://www.omim.org/entry/621210"},{"mim_id":"620874","title":"ADHESION G PROTEIN-COUPLED RECEPTOR F5; ADGRF5","url":"https://www.omim.org/entry/620874"},{"mim_id":"618190","title":"LUNG CANCER-ASSOCIATED TRANSCRIPT 1, NONCODING; LUCAT1","url":"https://www.omim.org/entry/618190"},{"mim_id":"614995","title":"INTERLEUKIN 17 RECEPTOR E; IL17RE","url":"https://www.omim.org/entry/614995"},{"mim_id":"611775","title":"KAWASAKI DISEASE","url":"https://www.omim.org/entry/611775"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Intermediate filaments","reliability":"Supported"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"bone marrow","ntpm":33387.3},{"tissue":"cervix","ntpm":14477.9},{"tissue":"esophagus","ntpm":36526.2},{"tissue":"vagina","ntpm":16753.2}],"url":"https://www.proteinatlas.org/search/S100A8"},"hgnc":{"alias_symbol":["P8","MRP8","MRP-8","60B8AG","CGLA","S100-A8"],"prev_symbol":["CAGA","CFAG"]},"alphafold":{"accession":"P05109","domains":[{"cath_id":"1.10.238.10","chopping":"3-89","consensus_level":"high","plddt":95.1707,"start":3,"end":89}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P05109","model_url":"https://alphafold.ebi.ac.uk/files/AF-P05109-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P05109-F1-predicted_aligned_error_v6.png","plddt_mean":93.06},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=S100A8","jax_strain_url":"https://www.jax.org/strain/search?query=S100A8"},"sequence":{"accession":"P05109","fasta_url":"https://rest.uniprot.org/uniprotkb/P05109.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P05109/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P05109"}},"corpus_meta":[{"pmid":"15343275","id":"PMC_15343275","title":"Oncogenic mechanisms of the Helicobacter pylori CagA protein.","date":"2004","source":"Nature reviews. Cancer","url":"https://pubmed.ncbi.nlm.nih.gov/15343275","citation_count":608,"is_preprint":false},{"pmid":"16846592","id":"PMC_16846592","title":"S100A8 and S100A9 in inflammation and cancer.","date":"2006","source":"Biochemical pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/16846592","citation_count":588,"is_preprint":false},{"pmid":"18192401","id":"PMC_18192401","title":"Transgenic expression of Helicobacter pylori CagA induces gastrointestinal and hematopoietic neoplasms in mouse.","date":"2008","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/18192401","citation_count":459,"is_preprint":false},{"pmid":"17507984","id":"PMC_17507984","title":"Helicobacter pylori CagA targets PAR1/MARK kinase to disrupt epithelial cell polarity.","date":"2007","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/17507984","citation_count":404,"is_preprint":false},{"pmid":"27492899","id":"PMC_27492899","title":"S100A8/A9: From basic science to clinical application.","date":"2016","source":"Pharmacology & therapeutics","url":"https://pubmed.ncbi.nlm.nih.gov/27492899","citation_count":361,"is_preprint":false},{"pmid":"31941367","id":"PMC_31941367","title":"Neutrophil-Derived S100A8/A9 Amplify Granulopoiesis After Myocardial Infarction.","date":"2020","source":"Circulation","url":"https://pubmed.ncbi.nlm.nih.gov/31941367","citation_count":260,"is_preprint":false},{"pmid":"9920411","id":"PMC_9920411","title":"Novel insights into structure and function of MRP8 (S100A8) and MRP14 (S100A9).","date":"1998","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/9920411","citation_count":233,"is_preprint":false},{"pmid":"24453429","id":"PMC_24453429","title":"S100A8 and S100A9: DAMPs at the crossroads between innate immunity, traditional risk factors, and cardiovascular disease.","date":"2013","source":"Mediators of inflammation","url":"https://pubmed.ncbi.nlm.nih.gov/24453429","citation_count":222,"is_preprint":false},{"pmid":"31804619","id":"PMC_31804619","title":"Molecular anatomy and pathogenic actions of Helicobacter pylori CagA that underpin gastric carcinogenesis.","date":"2019","source":"Cellular & molecular immunology","url":"https://pubmed.ncbi.nlm.nih.gov/31804619","citation_count":214,"is_preprint":false},{"pmid":"30083975","id":"PMC_30083975","title":"Calprotectin (S100A8/S100A9): a key protein between inflammation and cancer.","date":"2018","source":"Inflammation research : official journal of the European Histamine Research Society ... [et al.]","url":"https://pubmed.ncbi.nlm.nih.gov/30083975","citation_count":202,"is_preprint":false},{"pmid":"16367902","id":"PMC_16367902","title":"Helicobacter pylori CagA: a new paradigm for bacterial carcinogenesis.","date":"2005","source":"Cancer science","url":"https://pubmed.ncbi.nlm.nih.gov/16367902","citation_count":187,"is_preprint":false},{"pmid":"22095980","id":"PMC_22095980","title":"S100A8 and S100A9 in cardiovascular biology and disease.","date":"2011","source":"Arteriosclerosis, thrombosis, and vascular biology","url":"https://pubmed.ncbi.nlm.nih.gov/22095980","citation_count":181,"is_preprint":false},{"pmid":"22489132","id":"PMC_22489132","title":"Pro-inflammatory S100A8 and S100A9 proteins: self-assembly into multifunctional native and amyloid complexes.","date":"2012","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/22489132","citation_count":175,"is_preprint":false},{"pmid":"16216873","id":"PMC_16216873","title":"S100A8 and S100A9 in human arterial wall. Implications for atherogenesis.","date":"2005","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16216873","citation_count":162,"is_preprint":false},{"pmid":"32134742","id":"PMC_32134742","title":"S100A8/A9 regulates CD11b expression and neutrophil recruitment during chronic tuberculosis.","date":"2020","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/32134742","citation_count":118,"is_preprint":false},{"pmid":"38013255","id":"PMC_38013255","title":"Roles of S100A8, S100A9 and S100A12 in infection, inflammation and immunity.","date":"2023","source":"Immunology","url":"https://pubmed.ncbi.nlm.nih.gov/38013255","citation_count":115,"is_preprint":false},{"pmid":"10779802","id":"PMC_10779802","title":"IFN-gamma and TNF regulate macrophage expression of the chemotactic S100 protein S100A8.","date":"2000","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/10779802","citation_count":107,"is_preprint":false},{"pmid":"10534107","id":"PMC_10534107","title":"S100A8: emerging functions and regulation.","date":"1999","source":"Journal of leukocyte biology","url":"https://pubmed.ncbi.nlm.nih.gov/10534107","citation_count":104,"is_preprint":false},{"pmid":"25911757","id":"PMC_25911757","title":"Proinflammatory Proteins S100A8/S100A9 Activate NK Cells via Interaction with RAGE.","date":"2015","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/25911757","citation_count":100,"is_preprint":false},{"pmid":"28508421","id":"PMC_28508421","title":"Subversion of host kinases: a key network in cellular signaling hijacked by Helicobacter pylori CagA.","date":"2017","source":"Molecular microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/28508421","citation_count":96,"is_preprint":false},{"pmid":"15699168","id":"PMC_15699168","title":"Regulation of S100A8 by glucocorticoids.","date":"2005","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/15699168","citation_count":95,"is_preprint":false},{"pmid":"18832721","id":"PMC_18832721","title":"S-nitrosylated S100A8: novel anti-inflammatory properties.","date":"2008","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/18832721","citation_count":91,"is_preprint":false},{"pmid":"19835859","id":"PMC_19835859","title":"S100A8/A9: a Janus-faced molecule in cancer therapy and tumorgenesis.","date":"2009","source":"European journal of pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/19835859","citation_count":86,"is_preprint":false},{"pmid":"36026606","id":"PMC_36026606","title":"S100A8/A9 drives the formation of procoagulant platelets through GPIbα.","date":"2022","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/36026606","citation_count":83,"is_preprint":false},{"pmid":"26796299","id":"PMC_26796299","title":"CagA-mediated pathogenesis of Helicobacter pylori.","date":"2016","source":"Microbial pathogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/26796299","citation_count":81,"is_preprint":false},{"pmid":"16557568","id":"PMC_16557568","title":"Helicobacter pylori CagA -- a bacterial intruder conspiring gastric carcinogenesis.","date":"2006","source":"International journal of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/16557568","citation_count":80,"is_preprint":false},{"pmid":"27057553","id":"PMC_27057553","title":"Secretion of S100A8, S100A9, and S100A12 by Neutrophils Involves Reactive Oxygen Species and Potassium Efflux.","date":"2015","source":"Journal of immunology research","url":"https://pubmed.ncbi.nlm.nih.gov/27057553","citation_count":80,"is_preprint":false},{"pmid":"20919939","id":"PMC_20919939","title":"Oxidative modifications of DAMPs suppress inflammation: the case for S100A8 and S100A9.","date":"2011","source":"Antioxidants & redox signaling","url":"https://pubmed.ncbi.nlm.nih.gov/20919939","citation_count":75,"is_preprint":false},{"pmid":"17134680","id":"PMC_17134680","title":"CagA protein of Helicobacter pylori: a hijacker of gastric epithelial cell signaling.","date":"2006","source":"Biochemical pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/17134680","citation_count":75,"is_preprint":false},{"pmid":"19898558","id":"PMC_19898558","title":"S100A8/A9: a mediator of severe asthma pathogenesis and morbidity?","date":"2009","source":"Canadian journal of physiology and pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/19898558","citation_count":73,"is_preprint":false},{"pmid":"30728384","id":"PMC_30728384","title":"S100A8 & S100A9: Alarmin mediated inflammation in tendinopathy.","date":"2019","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/30728384","citation_count":71,"is_preprint":false},{"pmid":"11342660","id":"PMC_11342660","title":"Il-10 up-regulates macrophage expression of the S100 protein S100A8.","date":"2001","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/11342660","citation_count":71,"is_preprint":false},{"pmid":"26946461","id":"PMC_26946461","title":"Platelet-Derived S100A8/A9 and Cardiovascular Disease in Systemic Lupus Erythematosus.","date":"2016","source":"Arthritis & rheumatology (Hoboken, N.J.)","url":"https://pubmed.ncbi.nlm.nih.gov/26946461","citation_count":71,"is_preprint":false},{"pmid":"20105291","id":"PMC_20105291","title":"S100A8 and S100A9 in experimental osteoarthritis.","date":"2010","source":"Arthritis research & therapy","url":"https://pubmed.ncbi.nlm.nih.gov/20105291","citation_count":68,"is_preprint":false},{"pmid":"22505354","id":"PMC_22505354","title":"Hypoxia and HIF-1 increase S100A8 and S100A9 expression in prostate cancer.","date":"2012","source":"International journal of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/22505354","citation_count":62,"is_preprint":false},{"pmid":"33643287","id":"PMC_33643287","title":"Interleukin 17 Promotes Expression of Alarmins S100A8 and S100A9 During the Inflammatory Response of Keratinocytes.","date":"2021","source":"Frontiers in immunology","url":"https://pubmed.ncbi.nlm.nih.gov/33643287","citation_count":61,"is_preprint":false},{"pmid":"15943814","id":"PMC_15943814","title":"FGF-2, IL-1beta and TGF-beta regulate fibroblast expression of S100A8.","date":"2005","source":"The FEBS journal","url":"https://pubmed.ncbi.nlm.nih.gov/15943814","citation_count":61,"is_preprint":false},{"pmid":"32694806","id":"PMC_32694806","title":"GIP regulates inflammation and body weight by restraining myeloid-cell-derived S100A8/A9.","date":"2018","source":"Nature metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/32694806","citation_count":60,"is_preprint":false},{"pmid":"36521551","id":"PMC_36521551","title":"Inhibition of S100A8/A9 ameliorates renal interstitial fibrosis in diabetic nephropathy.","date":"2022","source":"Metabolism: clinical and experimental","url":"https://pubmed.ncbi.nlm.nih.gov/36521551","citation_count":57,"is_preprint":false},{"pmid":"21142608","id":"PMC_21142608","title":"S100A8 modulates mast cell function and suppresses eosinophil migration in acute asthma.","date":"2011","source":"Antioxidants & redox signaling","url":"https://pubmed.ncbi.nlm.nih.gov/21142608","citation_count":57,"is_preprint":false},{"pmid":"25080447","id":"PMC_25080447","title":"Bacterial CagA protein induces degradation of p53 protein in a p14ARF-dependent manner.","date":"2014","source":"Gut","url":"https://pubmed.ncbi.nlm.nih.gov/25080447","citation_count":55,"is_preprint":false},{"pmid":"36625265","id":"PMC_36625265","title":"Ponatinib Drives Cardiotoxicity by S100A8/A9-NLRP3-IL-1β Mediated Inflammation.","date":"2023","source":"Circulation research","url":"https://pubmed.ncbi.nlm.nih.gov/36625265","citation_count":54,"is_preprint":false},{"pmid":"17636430","id":"PMC_17636430","title":"S100A8/S100A9 and their association with cartilage and bone.","date":"2007","source":"Journal of molecular histology","url":"https://pubmed.ncbi.nlm.nih.gov/17636430","citation_count":54,"is_preprint":false},{"pmid":"27388991","id":"PMC_27388991","title":"Identification of an S100A8 Receptor Neuroplastin-β and its Heterodimer Formation with EMMPRIN.","date":"2016","source":"The Journal of investigative dermatology","url":"https://pubmed.ncbi.nlm.nih.gov/27388991","citation_count":54,"is_preprint":false},{"pmid":"19835955","id":"PMC_19835955","title":"Mrp-8 and -14 mediate CNS injury in focal cerebral ischemia.","date":"2009","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/19835955","citation_count":54,"is_preprint":false},{"pmid":"24532576","id":"PMC_24532576","title":"S100A8 induces IL-10 and protects against acute lung injury.","date":"2014","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/24532576","citation_count":54,"is_preprint":false},{"pmid":"29746703","id":"PMC_29746703","title":"S100A8/A9 promotes parenchymal damage and renal fibrosis in obstructive nephropathy.","date":"2018","source":"Clinical and experimental immunology","url":"https://pubmed.ncbi.nlm.nih.gov/29746703","citation_count":53,"is_preprint":false},{"pmid":"26135667","id":"PMC_26135667","title":"Inflammation-induced S100A8 activates Id3 and promotes colorectal tumorigenesis.","date":"2015","source":"International journal of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/26135667","citation_count":52,"is_preprint":false},{"pmid":"17090475","id":"PMC_17090475","title":"Up-regulation of S100A8 and S100A9 protein in bronchial epithelial cells by lipopolysaccharide.","date":"2006","source":"Experimental lung research","url":"https://pubmed.ncbi.nlm.nih.gov/17090475","citation_count":52,"is_preprint":false},{"pmid":"29563178","id":"PMC_29563178","title":"S100A8/A9 Drives Neuroinflammatory Priming and Protects against Anxiety-like Behavior after Sepsis.","date":"2018","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/29563178","citation_count":49,"is_preprint":false},{"pmid":"32250340","id":"PMC_32250340","title":"Bacterial CagA protein compromises tumor suppressor mechanisms in gastric epithelial cells.","date":"2020","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/32250340","citation_count":49,"is_preprint":false},{"pmid":"28074060","id":"PMC_28074060","title":"S100A8/A9 and S100A9 reduce acute lung injury.","date":"2017","source":"Immunology and cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/28074060","citation_count":46,"is_preprint":false},{"pmid":"17118755","id":"PMC_17118755","title":"The role of Helicobacter pylori CagA in gastric carcinogenesis.","date":"2006","source":"International journal of hematology","url":"https://pubmed.ncbi.nlm.nih.gov/17118755","citation_count":45,"is_preprint":false},{"pmid":"33523865","id":"PMC_33523865","title":"S100A8/S100A9 cytokine acts as a transcriptional coactivator during breast cellular transformation.","date":"2021","source":"Science advances","url":"https://pubmed.ncbi.nlm.nih.gov/33523865","citation_count":45,"is_preprint":false},{"pmid":"20363211","id":"PMC_20363211","title":"The CagA protein of Helicobacter pylori suppresses the functions of dendritic cell in mice.","date":"2010","source":"Archives of biochemistry and biophysics","url":"https://pubmed.ncbi.nlm.nih.gov/20363211","citation_count":45,"is_preprint":false},{"pmid":"25848057","id":"PMC_25848057","title":"Visualized macrophage dynamics and significance of S100A8 in obese fat.","date":"2015","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/25848057","citation_count":45,"is_preprint":false},{"pmid":"20712055","id":"PMC_20712055","title":"Helicobacter pylori CagA protein polymorphisms and their lack of association with pathogenesis.","date":"2010","source":"World journal of gastroenterology","url":"https://pubmed.ncbi.nlm.nih.gov/20712055","citation_count":43,"is_preprint":false},{"pmid":"26401027","id":"PMC_26401027","title":"Helicobacter pylori cagA Promoter Region Sequences Influence CagA Expression and Interleukin 8 Secretion.","date":"2015","source":"The Journal of infectious diseases","url":"https://pubmed.ncbi.nlm.nih.gov/26401027","citation_count":43,"is_preprint":false},{"pmid":"17613922","id":"PMC_17613922","title":"Helicobacter pylori and CagA seropositivity and its association with gastric and oesophageal carcinoma.","date":"2007","source":"Scandinavian journal of gastroenterology","url":"https://pubmed.ncbi.nlm.nih.gov/17613922","citation_count":42,"is_preprint":false},{"pmid":"31322196","id":"PMC_31322196","title":"Effect of S100A8 and S100A9 on expressions of cytokine and skin barrier protein in human keratinocytes.","date":"2019","source":"Molecular medicine reports","url":"https://pubmed.ncbi.nlm.nih.gov/31322196","citation_count":42,"is_preprint":false},{"pmid":"37799387","id":"PMC_37799387","title":"MANF brakes TLR4 signaling by competitively binding S100A8 with S100A9 to regulate macrophage phenotypes in hepatic fibrosis.","date":"2023","source":"Acta pharmaceutica Sinica. B","url":"https://pubmed.ncbi.nlm.nih.gov/37799387","citation_count":41,"is_preprint":false},{"pmid":"37701037","id":"PMC_37701037","title":"The functions and regulatory pathways of S100A8/A9 and its receptors in cancers.","date":"2023","source":"Frontiers in pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/37701037","citation_count":40,"is_preprint":false},{"pmid":"23800059","id":"PMC_23800059","title":"TNFα- and IL-17A-mediated S100A8 expression is regulated by p38 MAPK.","date":"2013","source":"Experimental dermatology","url":"https://pubmed.ncbi.nlm.nih.gov/23800059","citation_count":39,"is_preprint":false},{"pmid":"37124036","id":"PMC_37124036","title":"A review of signal pathway induced by virulent protein CagA of Helicobacter pylori.","date":"2023","source":"Frontiers in cellular and infection microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/37124036","citation_count":38,"is_preprint":false},{"pmid":"32198140","id":"PMC_32198140","title":"Proinflammatory S100A8 Induces PD-L1 Expression in Macrophages, Mediating Tumor Immune Escape.","date":"2020","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/32198140","citation_count":38,"is_preprint":false},{"pmid":"11283053","id":"PMC_11283053","title":"Assessment of Helicobacter pylori vacA and cagA genotypes and host serological response.","date":"2001","source":"Journal of clinical microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/11283053","citation_count":38,"is_preprint":false},{"pmid":"22031183","id":"PMC_22031183","title":"IL-1 receptor regulates S100A8/A9-dependent keratinocyte resistance to bacterial invasion.","date":"2011","source":"Mucosal immunology","url":"https://pubmed.ncbi.nlm.nih.gov/22031183","citation_count":38,"is_preprint":false},{"pmid":"33530496","id":"PMC_33530496","title":"Hypoxia-Induced S100A8 Expression Activates Microglial Inflammation and Promotes Neuronal Apoptosis.","date":"2021","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/33530496","citation_count":37,"is_preprint":false},{"pmid":"36310133","id":"PMC_36310133","title":"Alarming and Calming: Opposing Roles of S100A8/S100A9 Dimers and Tetramers on Monocytes.","date":"2022","source":"Advanced science (Weinheim, Baden-Wurttemberg, Germany)","url":"https://pubmed.ncbi.nlm.nih.gov/36310133","citation_count":36,"is_preprint":false},{"pmid":"35870523","id":"PMC_35870523","title":"S100A8 regulates autophagy-dependent ferroptosis in microglia after experimental subarachnoid hemorrhage.","date":"2022","source":"Experimental neurology","url":"https://pubmed.ncbi.nlm.nih.gov/35870523","citation_count":36,"is_preprint":false},{"pmid":"28609200","id":"PMC_28609200","title":"Significance of S100A8, S100A9 and calprotectin levels in bladder cancer.","date":"2017","source":"Scandinavian journal of clinical and laboratory investigation","url":"https://pubmed.ncbi.nlm.nih.gov/28609200","citation_count":36,"is_preprint":false},{"pmid":"30720226","id":"PMC_30720226","title":"Neuroplastin-β mediates S100A8/A9-induced lung cancer disseminative progression.","date":"2019","source":"Molecular carcinogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/30720226","citation_count":35,"is_preprint":false},{"pmid":"33361205","id":"PMC_33361205","title":"Deletion of S100a8 and S100a9 Enhances Skin Hyperplasia and Promotes the Th17 Response in Imiquimod-Induced Psoriasis.","date":"2020","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/33361205","citation_count":35,"is_preprint":false},{"pmid":"25423568","id":"PMC_25423568","title":"S100A8 is a novel therapeutic target for anaplastic thyroid carcinoma.","date":"2014","source":"The Journal of clinical endocrinology and metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/25423568","citation_count":34,"is_preprint":false},{"pmid":"31746424","id":"PMC_31746424","title":"S100A8 facilitates cholangiocarcinoma metastasis via upregulation of VEGF through TLR4/NF‑κB pathway activation.","date":"2019","source":"International journal of oncology","url":"https://pubmed.ncbi.nlm.nih.gov/31746424","citation_count":33,"is_preprint":false},{"pmid":"31416838","id":"PMC_31416838","title":"RETRACTED: CDX1 Expression Induced by CagA-Expressing Helicobacter pylori Promotes Gastric Tumorigenesis.","date":"2019","source":"Molecular cancer research : MCR","url":"https://pubmed.ncbi.nlm.nih.gov/31416838","citation_count":30,"is_preprint":false},{"pmid":"17939043","id":"PMC_17939043","title":"cagA gene and protein status among Iranian Helicobacter pylori strains.","date":"2007","source":"Digestive diseases and sciences","url":"https://pubmed.ncbi.nlm.nih.gov/17939043","citation_count":30,"is_preprint":false},{"pmid":"26883112","id":"PMC_26883112","title":"Involvement of calprotectin (S100A8/A9) in molecular pathways associated with HNSCC.","date":"2016","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/26883112","citation_count":30,"is_preprint":false},{"pmid":"26998104","id":"PMC_26998104","title":"S100A8/A9 is associated with estrogen receptor loss in breast cancer.","date":"2016","source":"Oncology letters","url":"https://pubmed.ncbi.nlm.nih.gov/26998104","citation_count":30,"is_preprint":false},{"pmid":"35543413","id":"PMC_35543413","title":"C/EBPδ-induced epigenetic changes control the dynamic gene transcription of S100a8 and S100a9.","date":"2022","source":"eLife","url":"https://pubmed.ncbi.nlm.nih.gov/35543413","citation_count":29,"is_preprint":false},{"pmid":"24670043","id":"PMC_24670043","title":"Inflammation and pancreatic cancer: molecular and functional interactions between S100A8, S100A9, NT-S100A8 and TGFβ1.","date":"2014","source":"Cell communication and signaling : CCS","url":"https://pubmed.ncbi.nlm.nih.gov/24670043","citation_count":29,"is_preprint":false},{"pmid":"32903598","id":"PMC_32903598","title":"S100A8 and S100A9 Promote Apoptosis of Chronic Eosinophilic Leukemia Cells.","date":"2020","source":"Frontiers in immunology","url":"https://pubmed.ncbi.nlm.nih.gov/32903598","citation_count":28,"is_preprint":false},{"pmid":"39809787","id":"PMC_39809787","title":"Helicobacter pylori CagA promotes gastric cancer immune escape by upregulating SQLE.","date":"2025","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/39809787","citation_count":26,"is_preprint":false},{"pmid":"30431097","id":"PMC_30431097","title":"CagA increases DNA methylation and decreases PTEN expression in human gastric cancer.","date":"2018","source":"Molecular medicine reports","url":"https://pubmed.ncbi.nlm.nih.gov/30431097","citation_count":26,"is_preprint":false},{"pmid":"9398886","id":"PMC_9398886","title":"Mixed infection with cagA-positive and cagA-negative strains of Helicobacter pylori.","date":"1996","source":"Helicobacter","url":"https://pubmed.ncbi.nlm.nih.gov/9398886","citation_count":26,"is_preprint":false},{"pmid":"21813645","id":"PMC_21813645","title":"Potentiation of Helicobacter pylori CagA protein virulence through homodimerization.","date":"2011","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/21813645","citation_count":26,"is_preprint":false},{"pmid":"37372165","id":"PMC_37372165","title":"S-100 Proteins: Basics and Applications as Biomarkers in Animals with Special Focus on Calgranulins (S100A8, A9, and A12).","date":"2023","source":"Biology","url":"https://pubmed.ncbi.nlm.nih.gov/37372165","citation_count":25,"is_preprint":false},{"pmid":"22957762","id":"PMC_22957762","title":"The distribution and expression of S100A8 and S100A9 in gingival epithelium of mice.","date":"2012","source":"Journal of periodontal research","url":"https://pubmed.ncbi.nlm.nih.gov/22957762","citation_count":24,"is_preprint":false},{"pmid":"27864293","id":"PMC_27864293","title":"Expressions of the CagA protein and CagA-signaling molecules predict Helicobacter pylori dependence of early-stage gastric DLBCL.","date":"2016","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/27864293","citation_count":24,"is_preprint":false},{"pmid":"38776909","id":"PMC_38776909","title":"Alarmin S100A8 imparts chemoresistance of esophageal cancer by reprogramming cancer-associated fibroblasts.","date":"2024","source":"Cell reports. Medicine","url":"https://pubmed.ncbi.nlm.nih.gov/38776909","citation_count":23,"is_preprint":false},{"pmid":"37978525","id":"PMC_37978525","title":"Deficiency of S100A8/A9 attenuates pulmonary microvascular leakage in septic mice.","date":"2023","source":"Respiratory research","url":"https://pubmed.ncbi.nlm.nih.gov/37978525","citation_count":23,"is_preprint":false},{"pmid":"31657090","id":"PMC_31657090","title":"Helicobacter pylori inhibits GKN1 expression via the CagA/p-ERK/AUF1 pathway.","date":"2019","source":"Helicobacter","url":"https://pubmed.ncbi.nlm.nih.gov/31657090","citation_count":23,"is_preprint":false},{"pmid":"11683921","id":"PMC_11683921","title":"Helicobacter pylori CagA: analysis of sequence diversity in relation to phosphorylation motifs and implications for the role of CagA as a virulence factor.","date":"2001","source":"Helicobacter","url":"https://pubmed.ncbi.nlm.nih.gov/11683921","citation_count":23,"is_preprint":false},{"pmid":"38403918","id":"PMC_38403918","title":"S100A8-enriched microglia populate the brain of tau-seeded and accelerated aging mice.","date":"2024","source":"Aging cell","url":"https://pubmed.ncbi.nlm.nih.gov/38403918","citation_count":22,"is_preprint":false},{"pmid":"37547329","id":"PMC_37547329","title":"Blockage of S100A8/A9 ameliorates septic nephropathy in mice.","date":"2023","source":"Frontiers in pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/37547329","citation_count":22,"is_preprint":false},{"pmid":"32854769","id":"PMC_32854769","title":"The alarmins S100A8 and S100A9 mediate acute pain in experimental synovitis.","date":"2020","source":"Arthritis research & therapy","url":"https://pubmed.ncbi.nlm.nih.gov/32854769","citation_count":22,"is_preprint":false},{"pmid":"29567886","id":"PMC_29567886","title":"CagA and VacA genes of Helicobacter pylori and their clinical relevance.","date":"2018","source":"Indian journal of pathology & microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/29567886","citation_count":21,"is_preprint":false},{"pmid":"29552168","id":"PMC_29552168","title":"Protein S100-A8: A potential metastasis-associated protein for breast cancer determined via iTRAQ quantitative proteomic and clinicopathological analysis.","date":"2018","source":"Oncology letters","url":"https://pubmed.ncbi.nlm.nih.gov/29552168","citation_count":21,"is_preprint":false},{"pmid":"25252120","id":"PMC_25252120","title":"Association of increased S100A8 serum protein with early pregnancy loss.","date":"2014","source":"American journal of reproductive immunology (New York, N.Y. : 1989)","url":"https://pubmed.ncbi.nlm.nih.gov/25252120","citation_count":21,"is_preprint":false},{"pmid":"27251136","id":"PMC_27251136","title":"Crystal structure of human S100A8 in complex with zinc and calcium.","date":"2016","source":"BMC structural biology","url":"https://pubmed.ncbi.nlm.nih.gov/27251136","citation_count":21,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":52610,"output_tokens":8822,"usd":0.14508,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":18858,"output_tokens":4421,"usd":0.102407,"stage2_stop_reason":"end_turn"},"total_usd":0.247487,"stage1_batch_id":"msgbatch_013LWZZT6MWaqB9qyTSeQBmU","stage2_batch_id":"msgbatch_0194ZzQaTGNpruoNJBbEMbt3","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2016,\n      \"finding\": \"Crystal structures of calcium- and zinc-loaded human S100A8 reveal that S100A8 binds two zinc ions per homodimer through symmetrical all-His tetrahedral coordination sites (His4 motif), and that zinc stabilizes S100A8 tetramerization by tightening the dimer-dimer interface; calcium induces the S100A8 tetramer.\",\n      \"method\": \"X-ray crystallography (two crystal forms), structural analysis\",\n      \"journal\": \"BMC structural biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structures with two independent crystal forms, direct structural validation of zinc-binding mode and tetramer interface\",\n      \"pmids\": [\"27251136\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Ca2+ and Zn2+-binding properties of S100A8 regulate its conformational state and oligomerization, including self-assembly into homodimers, heterodimers with S100A9, tetramers, and higher oligomers including amyloid fibrils; these transitions are linked to distinct functional states.\",\n      \"method\": \"Biophysical characterization, in vitro assembly assays, structural analysis\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal biophysical methods reported across labs, but primarily review-level synthesis\",\n      \"pmids\": [\"22489132\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"S100A8 undergoes S-nitrosylation at its single Cys residue (Cys34 in human); S-nitrosylated S100A8 (S100A8-SNO) transnitrosylates hemoglobin (acting as an NO transporter), suppresses mast cell activation, and inhibits leukocyte adhesion and extravasation in vivo; the Cys→Ala mutant is not S-nitrosylated, confirming the Cys residue is required.\",\n      \"method\": \"HPLC/mass spectrometry, biotin-switch assay, site-directed mutagenesis (Cys-to-Ala), intravital microscopy, in vitro mast cell assay\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — multiple orthogonal methods (MS, biotin-switch, mutagenesis, in vivo imaging) in single rigorous study establishing the PTM and its functional consequence\",\n      \"pmids\": [\"18832721\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"S100A8 suppresses IgE-crosslinking-induced mast cell degranulation and cytokine production (IL-6, IL-4, GM-CSF) via inhibition of intracellular ROS, reducing downstream LAT and ERK/MAPK phosphorylation; this activity requires the Cys41 residue, as the Cys41-Ala mutant lacks this anti-inflammatory activity. In vivo, S100A8 reduced eosinophil chemoattractant production and eosinophil infiltration in acute murine asthma.\",\n      \"method\": \"In vitro mast cell assay, site-directed mutagenesis, phosphorylation analysis, murine acute asthma model\",\n      \"journal\": \"Antioxidants & redox signaling\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — loss-of-function mutagenesis combined with in vitro and in vivo phenotypic readouts, multiple cytokine endpoints\",\n      \"pmids\": [\"21142608\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"S100A8 induces IL-10 expression specifically in airway epithelial cells in vivo; this requires the Cys42 residue (Cys42-Ala mutant fails to induce IL-10 and is less immunosuppressive). S100A8 suppresses LPS-induced acute lung injury by reducing NF-κB activation via an IκBα/Akt pathway and downmodulating oxidative stress pathways.\",\n      \"method\": \"Intranasal administration in BALB/c mice, Cys-to-Ala mutagenesis, gene expression time-course, LPS-induced ALI model\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vivo model with mutagenesis demonstrating Cys-dependence of IL-10 induction and pathway identification\",\n      \"pmids\": [\"24532576\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Neuroplastin-β (NPTN-β) was identified as a novel receptor for S100A8. Upon S100A8 binding, neuroplastin-β recruits GRB2 and activates ERK, resulting in keratinocyte proliferation. Neuroplastin-β and EMMPRIN (an S100A9 receptor) form a functional heterodimeric receptor complex on keratinocyte surfaces, and knockdown of both receptors suppressed cell proliferation and proinflammatory cytokine induction.\",\n      \"method\": \"Receptor identification, co-immunoprecipitation, knockdown experiments, transgenic mouse model, signaling pathway analysis\",\n      \"journal\": \"The Journal of investigative dermatology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — receptor identification with multiple validation approaches (Co-IP, KD, transgenic mouse), orthogonal signaling readouts\",\n      \"pmids\": [\"27388991\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"S100A8/A9 binding to neuroplastin-β (NPTNβ) in lung cancer cells activates TRAF2/RAS signaling, leading to downstream activation of NFIA, NFIB, and SPDEF transcription factors, promoting anchorage-independent growth, motility, and invasiveness.\",\n      \"method\": \"In vitro cancer cell assays, in vivo xenograft model, mechanistic signaling pathway analysis\",\n      \"journal\": \"Molecular carcinogenesis\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — single lab, multiple functional assays and pathway mapping, in vivo validation\",\n      \"pmids\": [\"30720226\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"S100A8/A9 binds GPIbα on platelets to drive formation of procoagulant (phosphatidylserine-positive) platelets, with a supporting role for CD36. This was established using recombinant GPIbα ectodomain as a blocking agent, platelets from a Bernard-Soulier syndrome patient lacking GPIb-IX-V, and platelets from mice deficient in the extracellular domain of GPIbα.\",\n      \"method\": \"Platelet functional assays, recombinant receptor blocking, patient platelets (Bernard-Soulier), GPIbα-knockout mouse platelets, flow cytometry, perfusion assays\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal genetic and biochemical approaches (human genetic disease, mouse KO, recombinant blocking) confirming GPIbα as the receptor\",\n      \"pmids\": [\"36026606\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"S100A8/S100A9 dimers activate TLR4, but extracellular calcium induces tetramer formation that prevents TLR4 binding. S100A8/A9 tetramers instead interact with CD69 on monocytes to dampen monocyte adhesion, migration, traction force generation, and immigration in vivo; thus the quaternary structure determines receptor selectivity and opposing inflammatory effects.\",\n      \"method\": \"In vitro monocyte functional assays (adhesion, migration, traction force), in vivo cutaneous granuloma model and contact dermatitis model, receptor blocking with anti-CD69\",\n      \"journal\": \"Advanced science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal in vitro and in vivo assays distinguishing dimer vs. tetramer receptor binding with functional consequence\",\n      \"pmids\": [\"36310133\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Neutrophil-released S100A8 and S100A9 bind TLR4 on naïve neutrophils, priming the NLRP3 inflammasome and promoting IL-1β secretion, which then stimulates IL-1R1 on hematopoietic stem and progenitor cells in bone marrow to drive granulopoiesis after myocardial infarction.\",\n      \"method\": \"Mouse LAD-ligation MI model, flow cytometry, genetic knockout (S100A8/A9-deficient), pharmacological disruption, transcriptome analysis\",\n      \"journal\": \"Circulation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic and pharmacological strategies defining the pathway sequentially (S100A8/A9 → TLR4 → NLRP3 → IL-1β → HSPC granulopoiesis)\",\n      \"pmids\": [\"31941367\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"S100A8/A9 interacts with RAGE on NK cells to enhance NKG2D ligand-mediated IFN-γ production; RAGE antagonistic peptide and anti-RAGE antibody blocked S100A8/A9-induced NK cell IFN-γ production, and RAGE inhibitor FPS-ZM1 enhanced tumor growth in vivo.\",\n      \"method\": \"Co-culture assays, RAGE inhibitors/blocking antibodies, in vivo tumor model with pharmacological RAGE inhibition\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — receptor identified by pharmacological blocking (multiple inhibitors), supported by in vivo model; single lab\",\n      \"pmids\": [\"25911757\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"S100A8 acts as an avid scavenger of reactive oxygen species including hypochlorite; in neutrophils and monocytes it is more sensitive to hypochlorite oxidation than albumin or LDL. S100A8-S100A9 complexes in atherosclerotic plaque undergo hypochlorite-mediated cross-linking. S100A8 in macrophages regulates NADPH-oxidase activity and fatty acid transport as part of the S100A8-S100A9 heterodimer.\",\n      \"method\": \"Oxidation sensitivity assays, immunoaffinity, redox biochemistry, human plaque characterization\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct biochemical assays showing oxidant-scavenging activity, single lab with multiple methods\",\n      \"pmids\": [\"16216873\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"IL-10 synergizes with LPS and IFN-γ to increase S100A8 mRNA (≥9-fold) and secreted S100A8 protein (~4-fold) in macrophages via increased gene transcription; the effect is dependent on de novo protein synthesis and maps to a 178-bp promoter region containing CCAAT-enhancing binding protein motifs. IL-10 induction is mechanistically distinct from STAT-pathway-dependent IL-10 target genes.\",\n      \"method\": \"Luciferase promoter reporter assay, blocking antibodies (endogenous IL-10), mRNA stability analysis, pharmacological pathway dissection\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — promoter mapping and transcriptional analysis with multiple pathway inhibitors, single lab\",\n      \"pmids\": [\"11342660\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"IFN-γ and TNF regulate S100A8 mRNA induction in murine macrophages through distinct kinetics; S100A8 gene induction is modulated by intracellular Ca2+ mobilization, protein kinase C, and MAPK pathways. Luciferase reporter assays confirmed LPS and IFN induce S100A8 gene transcription.\",\n      \"method\": \"Luciferase reporter assay, mRNA stability analysis, pharmacological inhibitors of signaling pathways (PKC, MAPK, Ca2+)\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reporter assay and pharmacological dissection identify transcriptional regulation pathways, single lab\",\n      \"pmids\": [\"10779802\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Glucocorticoids amplify LPS-induced S100A8 expression in macrophages, fibroblasts, and endothelial cells by increasing both gene transcription and mRNA half-life; this requires new protein synthesis, IL-10, cyclooxygenase-2 pathway products, and both ERK1/2 and p38 MAPK. Protein kinase A positively and PKC negatively regulate glucocorticoid enhancement. A NF1 motif at -58 bp is a candidate mediator. GCs also increase constitutive S100A8/A9 in human monocytes.\",\n      \"method\": \"Luciferase promoter reporter assay, gel shift/EMSA, pharmacological pathway inhibitors, mRNA stability assays\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple methods including promoter reporters and EMSA; single lab\",\n      \"pmids\": [\"15699168\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"FGF-2 (enhanced by heparin) and IL-1β are distinct inducers of S100A8 in fibroblasts acting through different promoter elements; induction is partially dependent on the MAPK pathway and requires new protein synthesis. TGF-β suppresses FGF-2/heparin-induced S100A8, possibly via decreased mRNA stability. S100A9 is not co-induced with S100A8 in fibroblasts under any tested condition.\",\n      \"method\": \"Real-time RT-PCR, promoter analysis, pharmacological MAPK inhibition, TGF-β suppression assay\",\n      \"journal\": \"The FEBS journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — promoter element mapping and pathway inhibitors; single lab\",\n      \"pmids\": [\"15943814\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"TNFα and IL-17A synergistically induce S100A8 mRNA and protein in human keratinocytes via a p38 MAPK-dependent mechanism; this was demonstrated by promoter luciferase reporter assay and p38 MAPK inhibitor blocking studies.\",\n      \"method\": \"qRT-PCR, luciferase reporter assay, p38 MAPK inhibitor\",\n      \"journal\": \"Experimental dermatology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reporter assay and pharmacological inhibition; single lab\",\n      \"pmids\": [\"23800059\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"The transcription factor C/EBPδ is a central regulator of S100a8 (and S100a9) expression; C/EBPδ-dependent JMJD3-mediated demethylation of H3K27me3 at S100a8/S100a9 promoters is required for their expression. C/EBPδ KO mice show decreased S100A8/A9 and reduced neutrophil recruitment in acute lung inflammation.\",\n      \"method\": \"Genome-wide CRISPR/Cas9 KO screen, C/EBPδ KO mouse model, ChIP, chromatin accessibility analysis, promoter binding assays\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — unbiased genome-wide CRISPR screen, in vivo genetic validation (KO mouse), and chromatin/epigenetic mechanism (H3K27me3 demethylation) confirmed by ChIP\",\n      \"pmids\": [\"35543413\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Hypoxia and HIF-1α increase S100A8 expression in prostate epithelial cells; functional hypoxia response elements (HREs) within the S100A8 promoter were identified by luciferase reporter assays, and direct HIF-1α binding to the S100A8 promoter was confirmed by chromatin immunoprecipitation.\",\n      \"method\": \"Promoter luciferase reporter assay, chromatin immunoprecipitation (ChIP), HIF-1α overexpression\",\n      \"journal\": \"International journal of cancer\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP and functional promoter assay in one study; single lab\",\n      \"pmids\": [\"22505354\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"S100A8 and S100A9 are recruited to promoters and enhancers in a model of breast cellular transformation and interact with transcription factors in nuclear extracts, activating transcription when artificially recruited to a target promoter; nuclear-specific expression of S100A8/A9 promotes oncogenic transcription and enhances breast transformation.\",\n      \"method\": \"ChIP-seq, nuclear extract co-immunoprecipitation, artificial recruitment (tethering) to target promoter, nuclear-specific expression constructs\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (ChIP-seq, Co-IP, artificial recruitment, functional transformation assay) in single study\",\n      \"pmids\": [\"33523865\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"S100A8 promotes anaplastic thyroid carcinoma (ATC) cell proliferation through interaction with RAGE, which activates p38, ERK1/2, and JNK signaling pathways in tumor cells; S100A8 knockdown in ATC cells reduced tumor growth and lung metastasis in orthotopic mouse models.\",\n      \"method\": \"RNAi-mediated stable knockdown, bioluminescent in vivo imaging, orthotopic mouse models, signaling pathway analysis\",\n      \"journal\": \"The Journal of clinical endocrinology and metabolism\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo loss-of-function with defined receptor (RAGE) and signaling readouts; single lab\",\n      \"pmids\": [\"25423568\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"S100A8 promotes colorectal tumorigenesis by activating Id3 (inhibitor of differentiation 3) downstream; S100A8 regulates colon cancer cell cycle and proliferation by inducing Id3 expression while inhibiting p21. Id3 expression is regulated by Smad5, which is directly phosphorylated by Akt1, establishing an S100A8→Akt1→Smad5→Id3 axis.\",\n      \"method\": \"Gene expression profiling, immunohistochemistry, proliferation/invasion assays, in vivo nude mouse metastasis model, signaling pathway analysis\",\n      \"journal\": \"International journal of cancer\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — pathway placement by functional assays in vitro and in vivo; single lab\",\n      \"pmids\": [\"26135667\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"S100A8 significantly induces PD-L1 expression in monocytes/macrophages (but not tumor cells) through TLR4 receptor engagement and multiple inflammation-related signaling pathways; S100A8 modulates histone modification of the PD-L1 promoter in monocytes/macrophages. S100A8-pretreated macrophages had immunosuppressive function and attenuated anti-tumor CTL activity.\",\n      \"method\": \"TLR4 blocking, pharmacological inhibitors, promoter chromatin analysis (histone modification), co-culture CTL assays, in vivo tumor model\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — receptor (TLR4) and epigenetic mechanism identified with multiple methods; single lab\",\n      \"pmids\": [\"32198140\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"MANF (mesencephalic astrocyte-derived neurotrophic factor) binds S100A8 to competitively block S100A8/A9 heterodimer formation, thereby inhibiting S100A8/A9-mediated TLR4-NF-κB signaling activation in macrophages. This was demonstrated by co-immunoprecipitation of MANF with S100A8.\",\n      \"method\": \"Co-immunoprecipitation (CO-IP), S100A8/A9 heterodimer formation assay, TLR4-NF-κB pathway analysis, genetic knockout mouse model\",\n      \"journal\": \"Acta pharmaceutica Sinica. B\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — CO-IP establishes direct protein-protein interaction; downstream signaling and in vivo validation; single lab\",\n      \"pmids\": [\"37799387\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"S100A8 deficiency promotes epithelial-to-mesenchymal transition (EMT) in renal tubular epithelial cells during diabetic nephropathy through the TLR4/NF-κB signaling pathway; high S100A8/A9 expression activates TLR4/NF-κB to promote EMT and renal interstitial fibrosis. CO-IP assay confirmed that compound AB38b inhibits EMT by interfering with S100A8/A9 expression/interaction.\",\n      \"method\": \"RNA silencing, overexpression lentiviral constructs, TLR4/NF-κB pathway analysis, CO-IP, in vivo diabetic mouse model\",\n      \"journal\": \"Metabolism: clinical and experimental\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss/gain of function with defined pathway (TLR4/NF-κB → EMT); single lab\",\n      \"pmids\": [\"36521551\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"S100A8 facilitates cholangiocarcinoma metastasis by activating the TLR4/NF-κB signaling pathway, which upregulates VEGF expression in CCA cells; this promotes vascular endothelial cell migration. Both in vitro and in vivo experiments confirmed that S100A8 overexpression enhanced, while knockdown attenuated, migration and metastasis.\",\n      \"method\": \"In vitro migration assays, in vivo xenograft model, TLR4/NF-κB pathway analysis, VEGF expression assays\",\n      \"journal\": \"International journal of oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — defined receptor-pathway axis (TLR4/NF-κB/VEGF) with in vitro and in vivo loss/gain of function; single lab\",\n      \"pmids\": [\"31746424\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Mrp8 (S100A8) and Mrp14 (S100A9) are endogenous TLR4 agonists that contribute to neuroinflammation after focal cerebral ischemia; Mrp14-deficient mice (which also lack Mrp8 protein) showed significantly reduced lesion volumes, less brain swelling, and reduced macrophage/microglia infiltration after transient focal ischemia.\",\n      \"method\": \"Mrp14 knockout mouse model, focal cerebral ischemia/reperfusion (1 h LAD ligation), lesion volume measurement, immunohistochemistry\",\n      \"journal\": \"Biochimica et biophysica acta\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic loss-of-function with defined phenotypic readout and pathway (TLR4); single lab\",\n      \"pmids\": [\"19835955\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"S100A8/A9 deficiency results in impaired upregulation of CD11b on neutrophils during chronic tuberculosis infection, which mediates neutrophil accumulation; S100A8/A9-deficient mice show improved Mycobacterium tuberculosis control specifically during chronic (not acute) TB.\",\n      \"method\": \"S100A8/A9-deficient mouse model, CD11b expression analysis, neutrophil depletion, flow cytometry\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic loss-of-function with mechanism (CD11b regulation) identified; single lab\",\n      \"pmids\": [\"32134742\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"S100A8 is rapidly and significantly increased in mature adipocytes during high-fat/high-sucrose diet, and acts as a chemoattractant for macrophages; recombinant S100A8 stimulated chemotactic migration of macrophages in vitro and in vivo and induced proinflammatory molecules (TNF-α and CCL2) in both macrophages and adipocytes. Anti-S100A8 antibody suppressed early macrophage mobilization in adipose tissue and ameliorated diet-induced insulin resistance.\",\n      \"method\": \"Intravital multiphoton imaging (LysM-EGFP transgenic mice), recombinant S100A8 chemotaxis assays, antibody neutralization in vivo\",\n      \"journal\": \"Proceedings of the National Academy of Sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct in vivo imaging combined with functional neutralization; single lab\",\n      \"pmids\": [\"25848057\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Secretion of S100A8/A9 from neutrophils is dependent on production of reactive oxygen species (ROS) and requires K+ efflux through ATP-sensitive K+ channels; particulate stimuli (MSU crystals, nanoparticles) and microbe-derived molecules (zymosan, HKCA) trigger secretion, while chemotactic fMLP does not induce S100A8/A9 secretion.\",\n      \"method\": \"Human neutrophil stimulation assays, ROS inhibitors, K+ channel blockers, ELISA for secreted S100 proteins\",\n      \"journal\": \"Journal of immunology research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — pharmacological dissection of secretion mechanism with multiple stimuli tested; single lab\",\n      \"pmids\": [\"27057553\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"IL-1 receptor (IL-1R) signaling in oral keratinocytes, triggered by IL-1α released from Listeria-infected cells, increases S100A8/A9 gene expression in a paracrine manner; S100A8/A9 expression is required for IL-1α-mediated resistance to Listeria invasion, as shRNA knockdown of S100A8/A9 abrogated this protection.\",\n      \"method\": \"Conditioned medium transfer, IL-1R antagonist blocking, shRNA knockdown of S100A8/A9, intracellular bacterial invasion assay\",\n      \"journal\": \"Mucosal immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — receptor blocking and gene knockdown establish causal relationship; single lab\",\n      \"pmids\": [\"22031183\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Ponatinib (tyrosine kinase inhibitor) activates the S100A8/A9-TLR4-NLRP3-IL-1β signaling pathway in cardiac and systemic myeloid cells, leading to myocardial inflammation and dysfunction; specific inhibitors of S100A9 (paquinimod), NLRP3 (CY-09), or broad immunosuppression with dexamethasone nearly abolished ponatinib-induced cardiac dysfunction.\",\n      \"method\": \"RNA sequencing (unbiased), in vitro and in vivo pharmacological inhibition, multiple mouse models with cardiovascular comorbidities\",\n      \"journal\": \"Circulation research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — pathway defined by unbiased transcriptomics and multiple pharmacological interventions; single lab\",\n      \"pmids\": [\"36625265\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"S100A8 and S100A9 homodimers (but not their heterodimeric complex) significantly upregulate chondrocyte ADAMTS1, ADAMTS4, ADAMTS5, MMP1, MMP3, and MMP13 gene expression, while decreasing collagen II and aggrecan mRNA, suggesting distinct functions of homodimer vs. heterodimer forms.\",\n      \"method\": \"qRT-PCR of primary ovine articular chondrocytes treated with recombinant homodimer vs. heterodimer forms\",\n      \"journal\": \"Arthritis research & therapy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — single method (qRT-PCR) in a clean comparative experimental design; single lab but clear structural specificity\",\n      \"pmids\": [\"20105291\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"IL-17A and IL-17F strongly induce S100A8 and S100A9 expression during early maturation stages of primary keratinocytes; S100A9-deficient keratinocytes show no significant role for S100A8/A9 in their own maturation or inflammatory response, and keratinocytes are not target cells for the proinflammatory effects of S100A8/A9.\",\n      \"method\": \"Primary S100A9-/- keratinocyte cultures, cytokine stimulation, imiquimod murine psoriasis model, transcriptome analysis\",\n      \"journal\": \"Frontiers in immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KO model and primary cells; defines IL-17 as upstream inducer; single lab\",\n      \"pmids\": [\"33643287\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Cancer-cell-derived S100A8 binds CD147 receptor on cancer-associated fibroblasts (CAFs) and triggers the intracellular RhoA-ROCK-MLC2-MRTF-A signaling pathway, inducing CAF polarization and leading to chemoresistance in esophageal squamous-cell carcinoma; blocking the S100A8-CD147 pathway improved chemotherapy efficiency.\",\n      \"method\": \"Patient-derived xenografts (PDX), receptor identification (CD147), signaling pathway analysis (RhoA-ROCK-MLC2-MRTF-A), CAF co-culture and functional assays\",\n      \"journal\": \"Cell reports. Medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — receptor identified with functional pathway validation and in vivo PDX model; single lab\",\n      \"pmids\": [\"38776909\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"S100A8 is a calcium- and zinc-binding alarmin that functions as a homodimer or heterodimer with S100A9, with quaternary structure (dimer vs. Ca2+-induced tetramer) determining receptor selectivity: dimers activate TLR4 to promote inflammation, while tetramers bind CD69 to dampen monocyte activity; extracellularly, S100A8 also signals through RAGE (activating ERK in keratinocytes/tumor cells), GPIbα (driving procoagulant platelet formation), neuroplastin-β (activating TRAF2/RAS/ERK signaling), and CD147 (activating RhoA-ROCK in fibroblasts); S100A8 undergoes S-nitrosylation at its single Cys residue to acquire anti-inflammatory NO-transport and mast cell-suppressing properties, and its transcription is regulated by C/EBPδ-dependent H3K27me3 demethylation, as well as by IL-10/LPS, glucocorticoids, FGF-2/IL-1β, IL-17A/F, and HIF-1α acting on defined promoter elements; intracellularly, S100A8/A9 can also translocate to the nucleus to act as a transcriptional co-activator during oncogenic transformation.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"S100A8 is a calcium- and zinc-binding alarmin whose conformational state — homodimer, S100A9 heterodimer, or Ca2+/Zn2+-induced tetramer — dictates which receptor it engages and therefore whether it drives or dampens inflammation [#0, #1, #8]. Crystallographic analysis shows that S100A8 binds two zinc ions per homodimer through all-His tetrahedral sites, with zinc and calcium tightening the dimer-dimer interface to favor tetramerization [#0]. This quaternary switch is functionally decisive: S100A8/A9 dimers activate TLR4, whereas Ca2+-induced tetramers cannot bind TLR4 and instead engage CD69 on monocytes to suppress adhesion, migration, and recruitment [#8]. Through TLR4, secreted S100A8/A9 acts as an endogenous agonist that primes the NLRP3 inflammasome and IL-1\\u03b2 secretion, driving granulopoiesis after myocardial infarction, neuroinflammation after cerebral ischemia, and myeloid-cell-mediated cardiac dysfunction [#9, #26, #31]. Beyond TLR4, S100A8 signals through a panel of receptors with cell-type-specific outputs: RAGE to activate ERK/p38/JNK in tumor cells and IFN-\\u03b3 in NK cells [#10, #20], neuroplastin-\\u03b2 (partnered with EMMPRIN) to recruit GRB2 and activate ERK or TRAF2/RAS for keratinocyte and cancer-cell proliferation [#5, #6], GPIb\\u03b1 to drive procoagulant platelet formation [#7], and CD147 to activate RhoA-ROCK signaling in cancer-associated fibroblasts [#34]. S100A8 also has redox-dependent roles, scavenging reactive oxygen species including hypochlorite [#11] and undergoing S-nitrosylation at its single cysteine to acquire NO-transport, mast-cell-suppressing, and anti-inflammatory activity that requires this Cys residue [#2, #3, #4]. Intracellularly, S100A8/A9 can localize to the nucleus, bind transcription factors, and act as a transcriptional co-activator that promotes oncogenic transformation [#19]. Its transcription is controlled by C/EBP\\u03b4-directed JMJD3-mediated H3K27me3 demethylation at the S100a8/a9 promoters and by inflammatory and hormonal inputs including IL-10/LPS, glucocorticoids, FGF-2/IL-1\\u03b2, IL-17A/F, and HIF-1\\u03b1 acting through defined promoter elements [#17, #12, #14, #15, #16, #18].\",\n  \"teleology\": [\n    {\n      \"year\": 2008,\n      \"claim\": \"Established that S100A8 carries a redox-active single cysteine that can be S-nitrosylated, converting it into an NO transporter and anti-inflammatory mediator, defining a post-translational switch on alarmin function.\",\n      \"evidence\": \"HPLC/MS, biotin-switch assay, Cys-to-Ala mutagenesis, and intravital microscopy in vivo\",\n      \"pmids\": [\"18832721\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not define which receptors mediate the anti-inflammatory effects of S100A8-SNO\", \"Physiological source of NO for in vivo S-nitrosylation not established\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Showed the cysteine residue is mechanistically required for S100A8 to suppress mast cell degranulation via ROS inhibition, linking the redox-active Cys to an intracellular signaling output.\",\n      \"evidence\": \"In vitro mast cell assays, Cys-to-Ala mutagenesis, phosphorylation analysis, and murine acute asthma model\",\n      \"pmids\": [\"21142608\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which extracellular S100A8 accesses intracellular ROS not defined\", \"Receptor mediating mast cell entry/signaling unidentified\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Extended the Cys-dependent anti-inflammatory program to airway epithelium, where S100A8 induces IL-10 and suppresses NF-\\u03baB via IkB\\u03b1/Akt.\",\n      \"evidence\": \"Intranasal administration in mice, Cys-to-Ala mutagenesis, and LPS-induced acute lung injury model\",\n      \"pmids\": [\"24532576\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Receptor transducing the IL-10-inducing signal not identified\", \"Reconciliation with TLR4-driven proinflammatory roles not addressed\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Resolved the structural basis for metal-dependent oligomerization, showing zinc binds via all-His sites to stabilize the tetramer interface and calcium induces tetramer formation — the structural foundation for state-dependent function.\",\n      \"evidence\": \"X-ray crystallography of Ca2+/Zn2+-loaded S100A8 in two crystal forms\",\n      \"pmids\": [\"27251136\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structures do not show receptor-bound complexes\", \"Did not directly link a given oligomer to a specific receptor\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Identified neuroplastin-\\u03b2 as an S100A8 receptor that, with EMMPRIN, forms a heterodimeric receptor recruiting GRB2 to drive ERK and keratinocyte proliferation, defining a non-TLR4 signaling axis.\",\n      \"evidence\": \"Receptor identification, co-immunoprecipitation, knockdown, and transgenic mouse model\",\n      \"pmids\": [\"27388991\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Which oligomeric state binds neuroplastin-\\u03b2 not defined\", \"Stoichiometry of the NPTN\\u03b2/EMMPRIN receptor complex unresolved\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Defined a sequential TLR4-NLRP3-IL-1\\u03b2 cascade by which neutrophil-released S100A8/A9 amplifies emergency granulopoiesis after myocardial infarction.\",\n      \"evidence\": \"Mouse MI model, S100A8/A9 knockout, pharmacological disruption, and transcriptome analysis\",\n      \"pmids\": [\"31941367\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not address oligomeric state required for TLR4 priming\", \"Contribution of S100A8 homodimer versus heterodimer not separated\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Demonstrated that quaternary structure determines receptor selectivity — Ca2+-induced tetramers lose TLR4 binding and instead engage CD69 to suppress monocytes — unifying the opposing pro- and anti-inflammatory roles under one structural switch.\",\n      \"evidence\": \"Monocyte functional assays, anti-CD69 blocking, and in vivo granuloma and contact dermatitis models\",\n      \"pmids\": [\"36310133\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not co-resolve tetramer-CD69 structure\", \"In vivo balance between dimer and tetramer pools under physiological Ca2+ not quantified\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Identified the GPIb\\u03b1 receptor on platelets as an S100A8/A9 target driving procoagulant platelet formation, extending alarmin signaling into hemostasis.\",\n      \"evidence\": \"Recombinant GPIb\\u03b1 blocking, Bernard-Soulier patient platelets, and GPIb\\u03b1-knockout mouse platelets\",\n      \"pmids\": [\"36026606\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Precise S100A8/A9 binding site on GPIb\\u03b1 not mapped\", \"Role of CD36 cofactor mechanistically incomplete\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Placed C/EBP\\u03b4 as a central transcriptional driver of S100a8/a9, acting through JMJD3-mediated H3K27me3 demethylation, revealing an epigenetic mechanism controlling alarmin expression.\",\n      \"evidence\": \"Genome-wide CRISPR/Cas9 screen, C/EBP\\u03b4 knockout mouse, and ChIP/chromatin accessibility analysis\",\n      \"pmids\": [\"35543413\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Stimulus-specific recruitment of C/EBP\\u03b4 to the locus not fully resolved\", \"Integration with other inducers (glucocorticoids, IL-17) not addressed\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Revealed an intracellular nuclear role in which S100A8/A9 are recruited to promoters/enhancers and act as transcriptional co-activators promoting oncogenic transformation, distinct from extracellular receptor signaling.\",\n      \"evidence\": \"ChIP-seq, nuclear extract co-IP, artificial tethering, and breast transformation assays\",\n      \"pmids\": [\"33523865\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct DNA-binding versus transcription-factor-tethered recruitment not fully distinguished\", \"Mechanism of nuclear import not defined\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Defined CD147 on cancer-associated fibroblasts as a further S100A8 receptor driving RhoA-ROCK signaling and chemoresistance, broadening the receptor repertoire into the tumor stroma.\",\n      \"evidence\": \"Patient-derived xenografts, receptor identification, and RhoA-ROCK-MLC2-MRTF-A pathway analysis\",\n      \"pmids\": [\"38776909\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab; reciprocal validation of CD147 binding limited\", \"Oligomeric state binding CD147 not defined\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How the multiple receptors (TLR4, CD69, RAGE, neuroplastin-\\u03b2, GPIb\\u03b1, CD147) are selected by S100A8's metal-dependent oligomeric and redox states in any given tissue context remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unified map linking specific oligomers/PTMs to each receptor in vivo\", \"Relative contributions of homodimer, heterodimer, and tetramer pools in physiological versus disease settings unquantified\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0048018\", \"supporting_discovery_ids\": [5, 7, 8, 10, 34]},\n      {\"term_id\": \"GO:0016209\", \"supporting_discovery_ids\": [2, 11]},\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [19]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [8]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [3, 11]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [19]},\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [28, 29]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [8, 9, 26, 27]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [5, 6, 10, 34]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [20, 21, 24, 25, 31]},\n      {\"term_id\": \"R-HSA-109582\", \"supporting_discovery_ids\": [7]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [17, 19]}\n    ],\n    \"complexes\": [\"S100A8/S100A9 heterodimer/tetramer\"],\n    \"partners\": [\"S100A9\", \"TLR4\", \"RAGE\", \"NPTN (neuroplastin-\\u03b2)\", \"GP1BA\", \"CD69\", \"CD147\", \"MANF\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":8,"faith_total":8,"faith_pct":100.0}}