{"gene":"THBS4","run_date":"2026-06-10T10:51:55","timeline":{"discoveries":[{"year":2013,"finding":"THBS4 (Thbs4) directly binds Notch1 receptor and promotes its endocytosis, activating downstream Notch signaling (including Nfia transcription factor upregulation) in SVZ neural stem cells to drive astrogenesis over neurogenesis after cortical injury. Thbs4 KO mice show defective injury-induced SVZ astrogenesis, aberrant glial scar formation, and increased microvascular hemorrhage.","method":"Notch1 receptor binding assay, endocytosis experiments, tamoxifen-inducible lineage tracing (nestin-creERtm4), Thbs4 homozygous knockout mouse phenotyping with cortical photothrombotic injury model","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct receptor binding and endocytosis experiments combined with in vivo genetic knockout and lineage tracing, replicated across multiple assays in a single rigorous study","pmids":["23615612"],"is_preprint":false},{"year":2020,"finding":"THBS4 interacts physically with integrin β1 (ITGB1), activating the FAK/PI3K/AKT pathway to promote HCC cell proliferation, metastasis, and EMT progression.","method":"Co-immunoprecipitation (IP), immunofluorescence, western blot, colony formation assay, transwell assay, xenograft tumor models","journal":"FASEB journal","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — direct Co-IP for binding, functional assays in vitro and in vivo, single lab with multiple orthogonal methods","pmids":["32567740"],"is_preprint":false},{"year":2020,"finding":"PDGFRβ signaling, activated downstream of TGFβ and PDGF-D, promotes post-translational modification of THBS4 from an incomplete to a complete form and drives its secretion via IP3R, STIM1, and Ca2+-signaling proteins, rather than increasing THBS4 mRNA levels.","method":"IP3R and STIM1 pharmacological blockade, PDGFRβ blockade, western blot for THBS4 protein levels vs. mRNA quantification, conditioned medium functional assays (adhesion, migration, proliferation of CCD-18co cells)","journal":"Cancers","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple pathway inhibitor experiments combined with protein vs. mRNA comparisons distinguishing post-translational regulation, single lab","pmids":["32899998"],"is_preprint":false},{"year":2021,"finding":"THBS4, upregulated in BM-MSCs migrating to sites of chronic H. pylori-induced gastric injury, interacts with integrin α2 to activate the PI3K/AKT pathway in endothelial cells, thereby promoting tumor angiogenesis.","method":"RNA-seq screening, xenograft tumor models, chicken chorioallantoic membrane assay, HUVEC tube formation assay, immunohistochemistry, immunofluorescence","journal":"Aging","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — multiple in vitro and in vivo angiogenesis assays with pathway analysis, single lab; binding interaction inferred functionally rather than direct structural evidence","pmids":["34390328"],"is_preprint":false},{"year":2024,"finding":"Histone methyltransferase MLL4 acts as a transcriptional activator of Thbs4 via mono-methylation of H3K4 (H3K4me1) and H3K27ac occupancy at the Thbs4 gene locus; MLL4 deficiency markedly reduces THBS4 expression, leading to aggravated ER stress and cardiac dysfunction under pressure overload.","method":"CUT&Tag-seq, RNA-seq, cardiomyocyte-specific Mll4 knockout mice (pressure overload model), MLL4 knockdown neonatal rat cardiomyocytes, western blot, phenylephrine-induced hypertrophy assay","journal":"Pharmacological research","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — CUT&Tag chromatin profiling combined with RNA-seq and in vivo cardiac-specific KO, multiple orthogonal methods establishing MLL4 as a direct epigenetic writer for THBS4","pmids":["38876442"],"is_preprint":false},{"year":2025,"finding":"Hypertrophic chondrocyte descendants (PADs) secrete THBS4 to promote angiogenesis; in vitro, exogenous THBS4 alone is sufficient to promote endothelial cell proliferation and tube formation, and rescues defective angiogenesis in HC-ablated metatarsal explants.","method":"Col10a1-Cre;R26DTA/+ HC genetic ablation mouse model, single-cell RNA-seq, in silico cell-cell communication analysis, immunostaining with tissue clearing, in vitro tube formation assay, metatarsal explant rescue assay","journal":"Bone research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic ablation with phenotypic rescue by recombinant THBS4, multiple orthogonal methods in single lab","pmids":["41207902"],"is_preprint":false},{"year":2025,"finding":"THBS4 knockdown in HTR-8/SVneo trophoblast cells inhibits TGF-β1 signaling pathway activity and reduces cell proliferation, migration, and invasion; these effects are reversed by TGF-β1 agonist treatment, placing THBS4 upstream of TGF-β1 signaling in trophoblast function.","method":"siRNA knockdown, TGF-β1 agonist (hyclate) rescue experiment, cell proliferation/migration/invasion assays, western blot","journal":"American journal of physiology. Cell physiology","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — loss-of-function with pharmacological rescue, single lab, multiple functional readouts","pmids":["40478535"],"is_preprint":false},{"year":2026,"finding":"Hypoxia induces THBS4 expression via HIF-1α, while TGF-β1 stimulation upregulates THBS4 through SMAD2 and p38 MAPK pathways; elevated THBS4 in turn promotes pulmonary artery smooth muscle cell proliferation, phenotypic modulation, and ECM remodeling in a self-reinforcing THBS4–TGF-β/SMAD2 axis driving pulmonary vascular remodeling. In vivo THBS4 silencing attenuated pulmonary vascular remodeling and right ventricular hypertrophy.","method":"Whole-transcriptomic analysis of rat PH models, functional assays on pulmonary artery smooth muscle cells, in vivo THBS4 silencing, HIF-1α/SMAD2/p38 MAPK pathway analysis","journal":"Hypertension","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple rat PH models, in vivo silencing, and multiple pathway analyses, single lab","pmids":["41873540"],"is_preprint":false},{"year":2025,"finding":"Rehmannin directly binds THBS4 (confirmed by surface plasmon resonance), and THBS4 knockdown enhances while THBS4 overexpression attenuates Rehmannin's inhibitory effects on fibroblast migration, ECM protein expression, and PI3K/AKT pathway activity in the context of pulmonary fibrosis.","method":"Surface plasmon resonance (SPR) binding assay, siRNA knockdown and overexpression in NIH-3T3 fibroblasts and BMDCs, transcriptomic and metabolomic profiling, in vivo bleomycin fibrosis model","journal":"International immunopharmacology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct binding confirmed by SPR with gain/loss-of-function in vitro and in vivo, single lab","pmids":["41202384"],"is_preprint":false},{"year":2025,"finding":"THBS4 is localized in the cell membrane and cytoplasm of DRG neurons; overexpression promotes axonal regeneration and reduces neuronal apoptosis, while knockdown has opposite effects. Thbs4 knockdown or overexpression significantly alters NF-κB and ERK signaling pathway activity, implicating these pathways in Thbs4-mediated peripheral nerve repair.","method":"siRNA knockdown, AAV-mediated overexpression, immunofluorescence staining, behavioral assays, electrophysiological recordings, transmission electron microscopy, sciatic nerve transection rat model","journal":"Biomedicines","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — bidirectional (KD and OE) in vivo experiments with multiple functional readouts; pathway assignment based on protein expression changes rather than direct mechanistic dissection","pmids":["41153662"],"is_preprint":false},{"year":2020,"finding":"THBS4 silencing in prostate cancer stem cells suppresses self-renewal and proliferation, promotes apoptosis, and reduces in vivo tumorigenicity; PI3K/AKT pathway inhibitor mimics THBS4 silencing effects, and THBS4 overexpression activates the PI3K/AKT pathway, placing THBS4 upstream of PI3K/AKT in cancer stem cell regulation.","method":"Flow cytometry stem cell sorting, shRNA-mediated THBS4 silencing and overexpression, PI3K/AKT inhibitor treatment, self-renewal/proliferation/apoptosis assays, in vivo tumorigenicity assay, western blot","journal":"The Prostate","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — epistasis established via pathway inhibitor rescue alongside gain/loss-of-function, single lab","pmids":["32421868"],"is_preprint":false},{"year":2026,"finding":"THBS4 enriched in PMSC-derived exosomes binds integrin α2 (ITG α2) on endothelial cells, activating the PI3K/AKT signaling pathway and enhancing endothelial cell migration and angiogenesis; in vivo administration of these exosomes alleviated preeclampsia symptoms in a rat model.","method":"Exosome isolation and characterization (TEM, nanoparticle tracking, western blot, proteomics), exosome uptake assay, transwell migration assay, tube formation assay, immunofluorescence, rat PE model with intraplacental injection","journal":"International journal of nanomedicine","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — functional receptor-ligand interaction demonstrated with multiple angiogenesis assays and in vivo rescue, single lab","pmids":["41878135"],"is_preprint":false},{"year":2011,"finding":"THBS4 is expressed and secreted by cancer-associated fibroblasts in diffuse-type gastric adenocarcinoma; tumor cells stimulate THBS4 transcription in fibroblasts.","method":"Immunohistochemical co-localization, in vitro secretion assays with cancer-associated fibroblasts, tumor cell co-culture experiments, quantitative RT-PCR","journal":"Modern pathology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — in vitro secretion and co-localization data establishing cellular source and paracrine regulation, single lab with limited mechanistic detail in abstract","pmids":["21701537"],"is_preprint":false},{"year":2025,"finding":"THBS4 knockdown in renal fibrosis models reduces expression of fibrosis-associated proteins and suppresses PI3K/AKT pathway activation (reduced p-AKT and p-PI3K); these effects are reversed by IGF-1 treatment, placing THBS4 upstream of PI3K/AKT-mediated renal fibrosis.","method":"UUO mouse model, TGF-β1-stimulated HK2 cell fibrosis model, THBS4 knockdown, IGF-1 rescue, Sirius red/Masson staining, immunohistochemistry, western blot, qPCR","journal":"Frontiers in bioscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo and in vitro models with pharmacological rescue establishing pathway position, single lab","pmids":["40765330"],"is_preprint":false},{"year":2024,"finding":"In a schizophrenia forebrain assembloid model, neuronal PTPRF signaling elicits THBS4 expression in microglia, and this aberrant neuron-glia signaling axis alters the neuronal transcriptome associated with synapse connectivity.","method":"Patient-derived mix-and-match forebrain assembloids, integrated modular gene expression analysis, combinatorial neuron/glia reconstitution experiments","journal":"bioRxiv","confidence":"Low","confidence_rationale":"Tier 3 / Weak — preprint, single assembloid model system, indirect pathway assignment without direct mechanistic dissection of THBS4 function","pmids":[],"is_preprint":true}],"current_model":"THBS4 is a secreted homopentameric extracellular matrix glycoprotein whose expression is transcriptionally activated by MLL4-mediated H3K4 mono-methylation and by upstream signals including HIF-1α and TGF-β1/SMAD2; it acts as a ligand for Notch1 receptor (promoting endocytosis and downstream Notch signaling in neural stem cells), integrin β1, and integrin α2 (activating FAK/PI3K/AKT in cancer and endothelial cells), and is post-translationally processed and secreted downstream of PDGFRβ/IP3R/STIM1/Ca2+ signaling, with established roles in injury-induced SVZ astrogenesis, tumor angiogenesis, bone vascular remodeling, pulmonary vascular remodeling, and peripheral nerve regeneration."},"narrative":{"mechanistic_narrative":"THBS4 is a secreted extracellular matrix glycoprotein that functions as a receptor ligand coordinating cell-fate decisions, vascular remodeling, and tissue repair across multiple organ contexts [PMID:23615612, PMID:41207902]. It acts as a ligand for the Notch1 receptor, directly binding Notch1 and promoting its endocytosis to activate downstream Notch signaling (including Nfia upregulation) in subventricular-zone neural stem cells, thereby driving injury-induced astrogenesis over neurogenesis [PMID:23615612]. THBS4 also engages integrins to activate the PI3K/AKT axis: it binds integrin β1 to stimulate FAK/PI3K/AKT and promote hepatocellular carcinoma proliferation, metastasis, and EMT [PMID:32567740], and binds integrin α2 on endothelial cells to activate PI3K/AKT and drive angiogenesis [PMID:34390328, PMID:41878135]. Consistent with a pro-survival, pro-proliferative output, THBS4 sits upstream of PI3K/AKT in prostate cancer stem cells [PMID:32421868] and of TGF-β1 signaling in trophoblasts [PMID:40478535], and is sufficient to promote endothelial proliferation and tube formation in skeletal angiogenesis [PMID:41207902]. THBS4 expression is controlled at distinct regulatory levels: transcriptionally by the histone methyltransferase MLL4 via H3K4me1/H3K27ac at the Thbs4 locus [PMID:38876442] and by HIF-1α and TGF-β1/SMAD2/p38 MAPK signaling in pulmonary vascular remodeling [PMID:41873540], and post-translationally through PDGFRβ/IP3R/STIM1/Ca2+-dependent maturation and secretion [PMID:32899998]. Through these activities it contributes to a self-reinforcing THBS4–TGF-β/SMAD2 axis in pulmonary vascular remodeling [PMID:41873540], fibrotic ECM remodeling in lung and kidney [PMID:41202384, PMID:40765330], and peripheral nerve regeneration [PMID:41153662].","teleology":[{"year":2013,"claim":"Established THBS4 as a direct ligand of the Notch1 receptor, answering how an ECM protein steers neural stem cell fate toward astrogenesis after injury.","evidence":"Notch1 binding and endocytosis assays with inducible lineage tracing and Thbs4 knockout phenotyping in a cortical injury model","pmids":["23615612"],"confidence":"High","gaps":["Structural basis of the THBS4–Notch1 interaction not defined","Whether THBS4 acts as a canonical Notch ligand or a co-regulator unresolved"]},{"year":2020,"claim":"Identified integrin β1 as a direct THBS4 receptor activating FAK/PI3K/AKT, linking THBS4 to oncogenic proliferation, metastasis, and EMT.","evidence":"Co-IP, immunofluorescence, in vitro functional assays, and xenograft models in hepatocellular carcinoma","pmids":["32567740"],"confidence":"Medium","gaps":["No reciprocal or structural validation of binding interface","Single tumor context"]},{"year":2020,"claim":"Showed THBS4 abundance is governed post-translationally rather than transcriptionally, defining a PDGFRβ/IP3R/STIM1/Ca2+ route to its maturation and secretion.","evidence":"Pathway inhibitor blockade with protein-versus-mRNA quantification and conditioned-medium functional assays","pmids":["32899998"],"confidence":"Medium","gaps":["Nature of the post-translational modification not molecularly identified","Single cell-line system"]},{"year":2020,"claim":"Placed THBS4 upstream of PI3K/AKT in cancer stem cell self-renewal, establishing pathway epistasis via inhibitor rescue.","evidence":"shRNA silencing/overexpression with PI3K/AKT inhibitor and in vivo tumorigenicity in prostate cancer stem cells","pmids":["32421868"],"confidence":"Medium","gaps":["Receptor mediating PI3K/AKT activation in this context not identified","Single lab"]},{"year":2021,"claim":"Defined integrin α2 as the endothelial receptor through which THBS4 activates PI3K/AKT to drive angiogenesis.","evidence":"RNA-seq screen, xenograft, CAM and HUVEC tube formation assays in a gastric injury context","pmids":["34390328"],"confidence":"Medium","gaps":["Binding inferred functionally without direct structural evidence","Single lab"]},{"year":2024,"claim":"Identified MLL4 as a direct epigenetic activator of Thbs4 transcription, connecting THBS4 expression to protection from cardiac ER stress under pressure overload.","evidence":"CUT&Tag-seq and RNA-seq with cardiomyocyte-specific Mll4 knockout and cardiomyocyte knockdown","pmids":["38876442"],"confidence":"High","gaps":["Downstream effectors of THBS4 in cardiomyocytes not dissected","Whether THBS4 acts cell-autonomously in heart unresolved"]},{"year":2025,"claim":"Demonstrated THBS4 is secreted by hypertrophic chondrocyte descendants and is alone sufficient to drive skeletal angiogenesis, rescuing ablation defects.","evidence":"Genetic HC ablation, single-cell RNA-seq, cell-cell communication analysis, and recombinant THBS4 metatarsal explant rescue","pmids":["41207902"],"confidence":"Medium","gaps":["Endothelial receptor in bone context not confirmed","Single lab"]},{"year":2025,"claim":"Placed THBS4 upstream of TGF-β1 signaling in trophoblast proliferation, migration, and invasion.","evidence":"siRNA knockdown with TGF-β1 agonist rescue and functional assays in HTR-8/SVneo cells","pmids":["40478535"],"confidence":"Medium","gaps":["Mechanism linking THBS4 to TGF-β1 pathway activation undefined","In vitro only"]},{"year":2025,"claim":"Established THBS4 as a direct binding target whose level tunes fibroblast ECM expression and PI3K/AKT activity in pulmonary fibrosis.","evidence":"SPR binding (Rehmannin), siRNA/overexpression in fibroblasts, and bleomycin fibrosis model","pmids":["41202384"],"confidence":"Medium","gaps":["Endogenous receptor mediating fibroblast effects not identified","Single lab"]},{"year":2025,"claim":"Showed THBS4 promotes axonal regeneration and limits neuronal apoptosis with associated changes in NF-κB and ERK signaling.","evidence":"siRNA knockdown and AAV overexpression with behavioral, electrophysiological, and ultrastructural readouts in a sciatic nerve transection model","pmids":["41153662"],"confidence":"Medium","gaps":["Pathway assignment based on expression changes, not mechanistic dissection","Receptor in neurons not identified"]},{"year":2025,"claim":"Placed THBS4 upstream of PI3K/AKT-mediated renal fibrosis via pathway epistasis.","evidence":"UUO and TGF-β1-stimulated HK2 models with THBS4 knockdown and IGF-1 rescue","pmids":["40765330"],"confidence":"Medium","gaps":["Receptor coupling THBS4 to PI3K/AKT in kidney unknown","Single lab"]},{"year":2026,"claim":"Defined a self-reinforcing THBS4–TGF-β/SMAD2 axis induced by hypoxia/HIF-1α and TGF-β1/SMAD2/p38 MAPK driving pulmonary vascular remodeling.","evidence":"Rat PH transcriptomics, PASMC functional assays, in vivo THBS4 silencing, and pathway analysis","pmids":["41873540"],"confidence":"Medium","gaps":["Receptor mediating PASMC effects not identified","Feedback loop mechanism partially defined"]},{"year":2026,"claim":"Showed exosome-delivered THBS4 binds endothelial integrin α2 to activate PI3K/AKT and rescue preeclampsia, extending the integrin α2 angiogenic mechanism to a therapeutic delivery context.","evidence":"Exosome characterization, uptake/migration/tube formation assays, and a rat preeclampsia model with intraplacental injection","pmids":["41878135"],"confidence":"Medium","gaps":["Direct binding interface not structurally resolved","Single lab"]},{"year":null,"claim":"How THBS4's distinct receptor engagements (Notch1, integrin β1, integrin α2) are selected in different tissues, and the structural basis of these interactions, remain unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of THBS4 with any receptor","Determinants of context-specific receptor choice unknown","Identity of receptors in fibroblast and neuronal contexts undefined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0048018","term_label":"receptor ligand activity","supporting_discovery_ids":[0,1,3,11]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,6]}],"localization":[{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[2,5,12]},{"term_id":"GO:0031012","term_label":"extracellular matrix","supporting_discovery_ids":[7]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[9]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[9]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,1,3,7,11]},{"term_id":"R-HSA-1474244","term_label":"Extracellular matrix organization","supporting_discovery_ids":[7,8,13]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[0,5]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[1,10,7]}],"complexes":[],"partners":["NOTCH1","ITGB1","ITGA2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P35443","full_name":"Thrombospondin-4","aliases":[],"length_aa":961,"mass_kda":105.9,"function":"Adhesive glycoprotein that mediates cell-to-cell and cell-to-matrix interactions and is involved in various processes including cellular proliferation, migration, adhesion and attachment, inflammatory response to CNS injury, regulation of vascular inflammation and adaptive responses of the heart to pressure overload and in myocardial function and remodeling. Binds to structural extracellular matrix (ECM) proteins and modulates the ECM in response to tissue damage, contributing to cardioprotective and adaptive ECM remodeling. Plays a role in ER stress response, via its interaction with the activating transcription factor 6 alpha (ATF6) which produces adaptive ER stress response factors and protects myocardium from pressure overload. May contribute to spinal presynaptic hypersensitivity and neuropathic pain states after peripheral nerve injury. May play a role in regulating protective astrogenesis from the subventricular zone (SVZ) niche after injury in a NOTCH1-dependent manner (By similarity)","subcellular_location":"Endoplasmic reticulum; Sarcoplasmic reticulum; Secreted; Secreted, extracellular space; Secreted, extracellular space, extracellular matrix","url":"https://www.uniprot.org/uniprotkb/P35443/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/THBS4","classification":"Not Classified","n_dependent_lines":1,"n_total_lines":1208,"dependency_fraction":0.0008278145695364238},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/THBS4","total_profiled":1310},"omim":[{"mim_id":"607855","title":"MUSCULAR DYSTROPHY, CONGENITAL MEROSIN-DEFICIENT, 1A; MDC1A","url":"https://www.omim.org/entry/607855"},{"mim_id":"600715","title":"THROMBOSPONDIN IV; THBS4","url":"https://www.omim.org/entry/600715"},{"mim_id":"253800","title":"MUSCULAR DYSTROPHY-DYSTROGLYCANOPATHY (CONGENITAL WITH BRAIN AND EYE ANOMALIES), TYPE A, 4; MDDGA4","url":"https://www.omim.org/entry/253800"},{"mim_id":"188060","title":"THROMBOSPONDIN I; THBS1","url":"https://www.omim.org/entry/188060"},{"mim_id":"163730","title":"NITRIC OXIDE SYNTHASE 2; NOS2","url":"https://www.omim.org/entry/163730"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Vesicles","reliability":"Approved"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"adipose tissue","ntpm":203.6},{"tissue":"heart muscle","ntpm":157.1},{"tissue":"smooth muscle","ntpm":234.9},{"tissue":"tongue","ntpm":200.5}],"url":"https://www.proteinatlas.org/search/THBS4"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"P35443","domains":[{"cath_id":"2.60.120.200","chopping":"30-202","consensus_level":"high","plddt":78.2502,"start":30,"end":202},{"cath_id":"2.60.120.200","chopping":"734-958","consensus_level":"high","plddt":93.3986,"start":734,"end":958},{"cath_id":"2.10.25","chopping":"383-421","consensus_level":"medium","plddt":85.3587,"start":383,"end":421}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P35443","model_url":"https://alphafold.ebi.ac.uk/files/AF-P35443-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P35443-F1-predicted_aligned_error_v6.png","plddt_mean":84.56},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=THBS4","jax_strain_url":"https://www.jax.org/strain/search?query=THBS4"},"sequence":{"accession":"P35443","fasta_url":"https://rest.uniprot.org/uniprotkb/P35443.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P35443/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P35443"}},"corpus_meta":[{"pmid":"23615612","id":"PMC_23615612","title":"Protective astrogenesis from the SVZ niche after injury is controlled by Notch modulator Thbs4.","date":"2013","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/23615612","citation_count":225,"is_preprint":false},{"pmid":"21701537","id":"PMC_21701537","title":"THBS4, a novel stromal molecule of diffuse-type gastric adenocarcinomas, identified by transcriptome-wide expression profiling.","date":"2011","source":"Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc","url":"https://pubmed.ncbi.nlm.nih.gov/21701537","citation_count":93,"is_preprint":false},{"pmid":"32567740","id":"PMC_32567740","title":"THBS4 promotes HCC progression by regulating ITGB1 via FAK/PI3K/AKT pathway.","date":"2020","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/32567740","citation_count":80,"is_preprint":false},{"pmid":"27357608","id":"PMC_27357608","title":"Reciprocal regulation of long noncoding RNAs THBS4‑003 and THBS4 control migration and invasion in prostate cancer cell lines.","date":"2016","source":"Molecular medicine reports","url":"https://pubmed.ncbi.nlm.nih.gov/27357608","citation_count":30,"is_preprint":false},{"pmid":"32421868","id":"PMC_32421868","title":"THBS4 silencing regulates the cancer stem cell-like properties in prostate cancer via blocking the PI3K/Akt pathway.","date":"2020","source":"The Prostate","url":"https://pubmed.ncbi.nlm.nih.gov/32421868","citation_count":30,"is_preprint":false},{"pmid":"35456219","id":"PMC_35456219","title":"Serum Proteins, HMMR, NXPH4, PITX1 and THBS4; A Panel of Biomarkers for Early Diagnosis of Hepatocellular Carcinoma.","date":"2022","source":"Journal of clinical medicine","url":"https://pubmed.ncbi.nlm.nih.gov/35456219","citation_count":21,"is_preprint":false},{"pmid":"32899998","id":"PMC_32899998","title":"Potential Role of PDGFRβ-Associated THBS4 in Colorectal Cancer Development.","date":"2020","source":"Cancers","url":"https://pubmed.ncbi.nlm.nih.gov/32899998","citation_count":20,"is_preprint":false},{"pmid":"34390328","id":"PMC_34390328","title":"THBS4/integrin α2 axis mediates BM-MSCs to promote angiogenesis in gastric cancer associated with chronic Helicobacter pylori infection.","date":"2021","source":"Aging","url":"https://pubmed.ncbi.nlm.nih.gov/34390328","citation_count":19,"is_preprint":false},{"pmid":"27160021","id":"PMC_27160021","title":"Associations of THBS2 and THBS4 polymorphisms to gastric cancer in a Southeast Chinese population.","date":"2016","source":"Cancer genetics","url":"https://pubmed.ncbi.nlm.nih.gov/27160021","citation_count":18,"is_preprint":false},{"pmid":"38876442","id":"PMC_38876442","title":"Histone methyltransferase MLL4 protects against pressure overload-induced heart failure via a THBS4-mediated protection in ER stress.","date":"2024","source":"Pharmacological research","url":"https://pubmed.ncbi.nlm.nih.gov/38876442","citation_count":13,"is_preprint":false},{"pmid":"40478535","id":"PMC_40478535","title":"THBS4 downregulation alters trophoblast function in preeclampsia via the TGF-β1/Smad signaling cascade.","date":"2025","source":"American journal of physiology. Cell physiology","url":"https://pubmed.ncbi.nlm.nih.gov/40478535","citation_count":7,"is_preprint":false},{"pmid":"12592708","id":"PMC_12592708","title":"The zebrafish thrombospondin 3 and 4 genes (thbs3 and thbs4): cDNA and protein structure.","date":"2002","source":"DNA sequence : the journal of DNA sequencing and mapping","url":"https://pubmed.ncbi.nlm.nih.gov/12592708","citation_count":7,"is_preprint":false},{"pmid":"23420636","id":"PMC_23420636","title":"Long-standing balancing selection in the THBS4 gene: influence on sex-specific brain expression and gray matter volumes in Alzheimer disease.","date":"2013","source":"Human mutation","url":"https://pubmed.ncbi.nlm.nih.gov/23420636","citation_count":7,"is_preprint":false},{"pmid":"35008203","id":"PMC_35008203","title":"DNA Methylation in INA, NHLH2, and THBS4 Is Associated with Metastatic Disease in Renal Cell Carcinoma.","date":"2021","source":"Cancers","url":"https://pubmed.ncbi.nlm.nih.gov/35008203","citation_count":6,"is_preprint":false},{"pmid":"32684116","id":"PMC_32684116","title":"Downregulation of Thbs4 caused by neurogenic niche changes promotes neuronal regeneration after traumatic brain injury.","date":"2020","source":"Neurological research","url":"https://pubmed.ncbi.nlm.nih.gov/32684116","citation_count":6,"is_preprint":false},{"pmid":"41207902","id":"PMC_41207902","title":"Descendants of hypertrophic chondrocytes promote angiogenesis by secreting THBS4 during bone growth and injury repair.","date":"2025","source":"Bone research","url":"https://pubmed.ncbi.nlm.nih.gov/41207902","citation_count":5,"is_preprint":false},{"pmid":"39732055","id":"PMC_39732055","title":"LncRNA-THBS4 affects granulosa cell proliferation and apoptosis in diminished ovarian reserve by regulating PI3K/AKT/mTOR signaling pathway.","date":"2024","source":"Journal of reproductive immunology","url":"https://pubmed.ncbi.nlm.nih.gov/39732055","citation_count":3,"is_preprint":false},{"pmid":"40303998","id":"PMC_40303998","title":"Transcriptome sequencing revealed that lymph node metastasis of papillary thyroid microcarcinoma is associated with high THBS4 expression and PDGFRA+ cancer-associated fibroblasts.","date":"2025","source":"Frontiers in oncology","url":"https://pubmed.ncbi.nlm.nih.gov/40303998","citation_count":1,"is_preprint":false},{"pmid":"41202384","id":"PMC_41202384","title":"Rehmannin attenuates bleomycin-induced pulmonary fibrosis via THBS4-dependent modulation of fibroblast-dendritic cell interplay and matrix dynamics.","date":"2025","source":"International immunopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/41202384","citation_count":1,"is_preprint":false},{"pmid":"41153662","id":"PMC_41153662","title":"Investigating How Thbs4 Regulates Degeneration and Regeneration of the Peripheral Nerve.","date":"2025","source":"Biomedicines","url":"https://pubmed.ncbi.nlm.nih.gov/41153662","citation_count":1,"is_preprint":false},{"pmid":"41873540","id":"PMC_41873540","title":"THBS4 Regulates Pulmonary Hypertension via TGF-β/SMAD2 Signaling.","date":"2026","source":"Hypertension (Dallas, Tex. : 1979)","url":"https://pubmed.ncbi.nlm.nih.gov/41873540","citation_count":0,"is_preprint":false},{"pmid":"40765330","id":"PMC_40765330","title":"The Role of THBS4 in Chronic Kidney Disease Fibrosis: From Clinical Observations to Molecular Mechanisms.","date":"2025","source":"Frontiers in bioscience (Landmark edition)","url":"https://pubmed.ncbi.nlm.nih.gov/40765330","citation_count":0,"is_preprint":false},{"pmid":"41878135","id":"PMC_41878135","title":"Exosomal THBS4 Derived From Human Placental Mesenchymal Stem Cells Promotes the Migration and Angiogenesis of the Endothelial Cells in Preeclampsia by Activating the Integrin α2/PI3K/AKT Axis.","date":"2026","source":"International journal of nanomedicine","url":"https://pubmed.ncbi.nlm.nih.gov/41878135","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.10.22.25338181","title":"A comprehensive genomic framework for identifying genes predisposing to homologous recombination repair deficient breast cancer","date":"2025-10-23","source":"bioRxiv","url":"https://doi.org/10.1101/2025.10.22.25338181","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.11.10.687675","title":"Isolation of functional supramolecular attack particles (SMAPs)","date":"2025-11-12","source":"bioRxiv","url":"https://doi.org/10.1101/2025.11.10.687675","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.12.22.629557","title":"Identification of neuron-glia signaling feedback in human schizophrenia using patient-derived, mix-and-match forebrain assembloids","date":"2024-12-23","source":"bioRxiv","url":"https://doi.org/10.1101/2024.12.22.629557","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":17632,"output_tokens":3978,"usd":0.056283,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":11825,"output_tokens":4095,"usd":0.08075,"stage2_stop_reason":"end_turn"},"total_usd":0.137033,"stage1_batch_id":"msgbatch_017qqVz33Ga63SCDwzb35XPb","stage2_batch_id":"msgbatch_01Scr2Ei9x4HJMiRGxwrmvLK","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2013,\n      \"finding\": \"THBS4 (Thbs4) directly binds Notch1 receptor and promotes its endocytosis, activating downstream Notch signaling (including Nfia transcription factor upregulation) in SVZ neural stem cells to drive astrogenesis over neurogenesis after cortical injury. Thbs4 KO mice show defective injury-induced SVZ astrogenesis, aberrant glial scar formation, and increased microvascular hemorrhage.\",\n      \"method\": \"Notch1 receptor binding assay, endocytosis experiments, tamoxifen-inducible lineage tracing (nestin-creERtm4), Thbs4 homozygous knockout mouse phenotyping with cortical photothrombotic injury model\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct receptor binding and endocytosis experiments combined with in vivo genetic knockout and lineage tracing, replicated across multiple assays in a single rigorous study\",\n      \"pmids\": [\"23615612\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"THBS4 interacts physically with integrin β1 (ITGB1), activating the FAK/PI3K/AKT pathway to promote HCC cell proliferation, metastasis, and EMT progression.\",\n      \"method\": \"Co-immunoprecipitation (IP), immunofluorescence, western blot, colony formation assay, transwell assay, xenograft tumor models\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — direct Co-IP for binding, functional assays in vitro and in vivo, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"32567740\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"PDGFRβ signaling, activated downstream of TGFβ and PDGF-D, promotes post-translational modification of THBS4 from an incomplete to a complete form and drives its secretion via IP3R, STIM1, and Ca2+-signaling proteins, rather than increasing THBS4 mRNA levels.\",\n      \"method\": \"IP3R and STIM1 pharmacological blockade, PDGFRβ blockade, western blot for THBS4 protein levels vs. mRNA quantification, conditioned medium functional assays (adhesion, migration, proliferation of CCD-18co cells)\",\n      \"journal\": \"Cancers\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple pathway inhibitor experiments combined with protein vs. mRNA comparisons distinguishing post-translational regulation, single lab\",\n      \"pmids\": [\"32899998\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"THBS4, upregulated in BM-MSCs migrating to sites of chronic H. pylori-induced gastric injury, interacts with integrin α2 to activate the PI3K/AKT pathway in endothelial cells, thereby promoting tumor angiogenesis.\",\n      \"method\": \"RNA-seq screening, xenograft tumor models, chicken chorioallantoic membrane assay, HUVEC tube formation assay, immunohistochemistry, immunofluorescence\",\n      \"journal\": \"Aging\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — multiple in vitro and in vivo angiogenesis assays with pathway analysis, single lab; binding interaction inferred functionally rather than direct structural evidence\",\n      \"pmids\": [\"34390328\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Histone methyltransferase MLL4 acts as a transcriptional activator of Thbs4 via mono-methylation of H3K4 (H3K4me1) and H3K27ac occupancy at the Thbs4 gene locus; MLL4 deficiency markedly reduces THBS4 expression, leading to aggravated ER stress and cardiac dysfunction under pressure overload.\",\n      \"method\": \"CUT&Tag-seq, RNA-seq, cardiomyocyte-specific Mll4 knockout mice (pressure overload model), MLL4 knockdown neonatal rat cardiomyocytes, western blot, phenylephrine-induced hypertrophy assay\",\n      \"journal\": \"Pharmacological research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — CUT&Tag chromatin profiling combined with RNA-seq and in vivo cardiac-specific KO, multiple orthogonal methods establishing MLL4 as a direct epigenetic writer for THBS4\",\n      \"pmids\": [\"38876442\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Hypertrophic chondrocyte descendants (PADs) secrete THBS4 to promote angiogenesis; in vitro, exogenous THBS4 alone is sufficient to promote endothelial cell proliferation and tube formation, and rescues defective angiogenesis in HC-ablated metatarsal explants.\",\n      \"method\": \"Col10a1-Cre;R26DTA/+ HC genetic ablation mouse model, single-cell RNA-seq, in silico cell-cell communication analysis, immunostaining with tissue clearing, in vitro tube formation assay, metatarsal explant rescue assay\",\n      \"journal\": \"Bone research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic ablation with phenotypic rescue by recombinant THBS4, multiple orthogonal methods in single lab\",\n      \"pmids\": [\"41207902\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"THBS4 knockdown in HTR-8/SVneo trophoblast cells inhibits TGF-β1 signaling pathway activity and reduces cell proliferation, migration, and invasion; these effects are reversed by TGF-β1 agonist treatment, placing THBS4 upstream of TGF-β1 signaling in trophoblast function.\",\n      \"method\": \"siRNA knockdown, TGF-β1 agonist (hyclate) rescue experiment, cell proliferation/migration/invasion assays, western blot\",\n      \"journal\": \"American journal of physiology. Cell physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — loss-of-function with pharmacological rescue, single lab, multiple functional readouts\",\n      \"pmids\": [\"40478535\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"Hypoxia induces THBS4 expression via HIF-1α, while TGF-β1 stimulation upregulates THBS4 through SMAD2 and p38 MAPK pathways; elevated THBS4 in turn promotes pulmonary artery smooth muscle cell proliferation, phenotypic modulation, and ECM remodeling in a self-reinforcing THBS4–TGF-β/SMAD2 axis driving pulmonary vascular remodeling. In vivo THBS4 silencing attenuated pulmonary vascular remodeling and right ventricular hypertrophy.\",\n      \"method\": \"Whole-transcriptomic analysis of rat PH models, functional assays on pulmonary artery smooth muscle cells, in vivo THBS4 silencing, HIF-1α/SMAD2/p38 MAPK pathway analysis\",\n      \"journal\": \"Hypertension\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple rat PH models, in vivo silencing, and multiple pathway analyses, single lab\",\n      \"pmids\": [\"41873540\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Rehmannin directly binds THBS4 (confirmed by surface plasmon resonance), and THBS4 knockdown enhances while THBS4 overexpression attenuates Rehmannin's inhibitory effects on fibroblast migration, ECM protein expression, and PI3K/AKT pathway activity in the context of pulmonary fibrosis.\",\n      \"method\": \"Surface plasmon resonance (SPR) binding assay, siRNA knockdown and overexpression in NIH-3T3 fibroblasts and BMDCs, transcriptomic and metabolomic profiling, in vivo bleomycin fibrosis model\",\n      \"journal\": \"International immunopharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct binding confirmed by SPR with gain/loss-of-function in vitro and in vivo, single lab\",\n      \"pmids\": [\"41202384\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"THBS4 is localized in the cell membrane and cytoplasm of DRG neurons; overexpression promotes axonal regeneration and reduces neuronal apoptosis, while knockdown has opposite effects. Thbs4 knockdown or overexpression significantly alters NF-κB and ERK signaling pathway activity, implicating these pathways in Thbs4-mediated peripheral nerve repair.\",\n      \"method\": \"siRNA knockdown, AAV-mediated overexpression, immunofluorescence staining, behavioral assays, electrophysiological recordings, transmission electron microscopy, sciatic nerve transection rat model\",\n      \"journal\": \"Biomedicines\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — bidirectional (KD and OE) in vivo experiments with multiple functional readouts; pathway assignment based on protein expression changes rather than direct mechanistic dissection\",\n      \"pmids\": [\"41153662\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"THBS4 silencing in prostate cancer stem cells suppresses self-renewal and proliferation, promotes apoptosis, and reduces in vivo tumorigenicity; PI3K/AKT pathway inhibitor mimics THBS4 silencing effects, and THBS4 overexpression activates the PI3K/AKT pathway, placing THBS4 upstream of PI3K/AKT in cancer stem cell regulation.\",\n      \"method\": \"Flow cytometry stem cell sorting, shRNA-mediated THBS4 silencing and overexpression, PI3K/AKT inhibitor treatment, self-renewal/proliferation/apoptosis assays, in vivo tumorigenicity assay, western blot\",\n      \"journal\": \"The Prostate\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — epistasis established via pathway inhibitor rescue alongside gain/loss-of-function, single lab\",\n      \"pmids\": [\"32421868\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"THBS4 enriched in PMSC-derived exosomes binds integrin α2 (ITG α2) on endothelial cells, activating the PI3K/AKT signaling pathway and enhancing endothelial cell migration and angiogenesis; in vivo administration of these exosomes alleviated preeclampsia symptoms in a rat model.\",\n      \"method\": \"Exosome isolation and characterization (TEM, nanoparticle tracking, western blot, proteomics), exosome uptake assay, transwell migration assay, tube formation assay, immunofluorescence, rat PE model with intraplacental injection\",\n      \"journal\": \"International journal of nanomedicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — functional receptor-ligand interaction demonstrated with multiple angiogenesis assays and in vivo rescue, single lab\",\n      \"pmids\": [\"41878135\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"THBS4 is expressed and secreted by cancer-associated fibroblasts in diffuse-type gastric adenocarcinoma; tumor cells stimulate THBS4 transcription in fibroblasts.\",\n      \"method\": \"Immunohistochemical co-localization, in vitro secretion assays with cancer-associated fibroblasts, tumor cell co-culture experiments, quantitative RT-PCR\",\n      \"journal\": \"Modern pathology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — in vitro secretion and co-localization data establishing cellular source and paracrine regulation, single lab with limited mechanistic detail in abstract\",\n      \"pmids\": [\"21701537\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"THBS4 knockdown in renal fibrosis models reduces expression of fibrosis-associated proteins and suppresses PI3K/AKT pathway activation (reduced p-AKT and p-PI3K); these effects are reversed by IGF-1 treatment, placing THBS4 upstream of PI3K/AKT-mediated renal fibrosis.\",\n      \"method\": \"UUO mouse model, TGF-β1-stimulated HK2 cell fibrosis model, THBS4 knockdown, IGF-1 rescue, Sirius red/Masson staining, immunohistochemistry, western blot, qPCR\",\n      \"journal\": \"Frontiers in bioscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo and in vitro models with pharmacological rescue establishing pathway position, single lab\",\n      \"pmids\": [\"40765330\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"In a schizophrenia forebrain assembloid model, neuronal PTPRF signaling elicits THBS4 expression in microglia, and this aberrant neuron-glia signaling axis alters the neuronal transcriptome associated with synapse connectivity.\",\n      \"method\": \"Patient-derived mix-and-match forebrain assembloids, integrated modular gene expression analysis, combinatorial neuron/glia reconstitution experiments\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — preprint, single assembloid model system, indirect pathway assignment without direct mechanistic dissection of THBS4 function\",\n      \"pmids\": [],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"THBS4 is a secreted homopentameric extracellular matrix glycoprotein whose expression is transcriptionally activated by MLL4-mediated H3K4 mono-methylation and by upstream signals including HIF-1α and TGF-β1/SMAD2; it acts as a ligand for Notch1 receptor (promoting endocytosis and downstream Notch signaling in neural stem cells), integrin β1, and integrin α2 (activating FAK/PI3K/AKT in cancer and endothelial cells), and is post-translationally processed and secreted downstream of PDGFRβ/IP3R/STIM1/Ca2+ signaling, with established roles in injury-induced SVZ astrogenesis, tumor angiogenesis, bone vascular remodeling, pulmonary vascular remodeling, and peripheral nerve regeneration.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"THBS4 is a secreted extracellular matrix glycoprotein that functions as a receptor ligand coordinating cell-fate decisions, vascular remodeling, and tissue repair across multiple organ contexts [#0, #5]. It acts as a ligand for the Notch1 receptor, directly binding Notch1 and promoting its endocytosis to activate downstream Notch signaling (including Nfia upregulation) in subventricular-zone neural stem cells, thereby driving injury-induced astrogenesis over neurogenesis [#0]. THBS4 also engages integrins to activate the PI3K/AKT axis: it binds integrin \\u03b21 to stimulate FAK/PI3K/AKT and promote hepatocellular carcinoma proliferation, metastasis, and EMT [#1], and binds integrin \\u03b12 on endothelial cells to activate PI3K/AKT and drive angiogenesis [#3, #11]. Consistent with a pro-survival, pro-proliferative output, THBS4 sits upstream of PI3K/AKT in prostate cancer stem cells [#10] and of TGF-\\u03b21 signaling in trophoblasts [#6], and is sufficient to promote endothelial proliferation and tube formation in skeletal angiogenesis [#5]. THBS4 expression is controlled at distinct regulatory levels: transcriptionally by the histone methyltransferase MLL4 via H3K4me1/H3K27ac at the Thbs4 locus [#4] and by HIF-1\\u03b1 and TGF-\\u03b21/SMAD2/p38 MAPK signaling in pulmonary vascular remodeling [#7], and post-translationally through PDGFR\\u03b2/IP3R/STIM1/Ca2+-dependent maturation and secretion [#2]. Through these activities it contributes to a self-reinforcing THBS4\\u2013TGF-\\u03b2/SMAD2 axis in pulmonary vascular remodeling [#7], fibrotic ECM remodeling in lung and kidney [#8, #13], and peripheral nerve regeneration [#9].\",\n  \"teleology\": [\n    {\n      \"year\": 2013,\n      \"claim\": \"Established THBS4 as a direct ligand of the Notch1 receptor, answering how an ECM protein steers neural stem cell fate toward astrogenesis after injury.\",\n      \"evidence\": \"Notch1 binding and endocytosis assays with inducible lineage tracing and Thbs4 knockout phenotyping in a cortical injury model\",\n      \"pmids\": [\"23615612\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of the THBS4\\u2013Notch1 interaction not defined\", \"Whether THBS4 acts as a canonical Notch ligand or a co-regulator unresolved\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Identified integrin \\u03b21 as a direct THBS4 receptor activating FAK/PI3K/AKT, linking THBS4 to oncogenic proliferation, metastasis, and EMT.\",\n      \"evidence\": \"Co-IP, immunofluorescence, in vitro functional assays, and xenograft models in hepatocellular carcinoma\",\n      \"pmids\": [\"32567740\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No reciprocal or structural validation of binding interface\", \"Single tumor context\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Showed THBS4 abundance is governed post-translationally rather than transcriptionally, defining a PDGFR\\u03b2/IP3R/STIM1/Ca2+ route to its maturation and secretion.\",\n      \"evidence\": \"Pathway inhibitor blockade with protein-versus-mRNA quantification and conditioned-medium functional assays\",\n      \"pmids\": [\"32899998\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Nature of the post-translational modification not molecularly identified\", \"Single cell-line system\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Placed THBS4 upstream of PI3K/AKT in cancer stem cell self-renewal, establishing pathway epistasis via inhibitor rescue.\",\n      \"evidence\": \"shRNA silencing/overexpression with PI3K/AKT inhibitor and in vivo tumorigenicity in prostate cancer stem cells\",\n      \"pmids\": [\"32421868\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Receptor mediating PI3K/AKT activation in this context not identified\", \"Single lab\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Defined integrin \\u03b12 as the endothelial receptor through which THBS4 activates PI3K/AKT to drive angiogenesis.\",\n      \"evidence\": \"RNA-seq screen, xenograft, CAM and HUVEC tube formation assays in a gastric injury context\",\n      \"pmids\": [\"34390328\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Binding inferred functionally without direct structural evidence\", \"Single lab\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identified MLL4 as a direct epigenetic activator of Thbs4 transcription, connecting THBS4 expression to protection from cardiac ER stress under pressure overload.\",\n      \"evidence\": \"CUT&Tag-seq and RNA-seq with cardiomyocyte-specific Mll4 knockout and cardiomyocyte knockdown\",\n      \"pmids\": [\"38876442\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Downstream effectors of THBS4 in cardiomyocytes not dissected\", \"Whether THBS4 acts cell-autonomously in heart unresolved\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Demonstrated THBS4 is secreted by hypertrophic chondrocyte descendants and is alone sufficient to drive skeletal angiogenesis, rescuing ablation defects.\",\n      \"evidence\": \"Genetic HC ablation, single-cell RNA-seq, cell-cell communication analysis, and recombinant THBS4 metatarsal explant rescue\",\n      \"pmids\": [\"41207902\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Endothelial receptor in bone context not confirmed\", \"Single lab\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Placed THBS4 upstream of TGF-\\u03b21 signaling in trophoblast proliferation, migration, and invasion.\",\n      \"evidence\": \"siRNA knockdown with TGF-\\u03b21 agonist rescue and functional assays in HTR-8/SVneo cells\",\n      \"pmids\": [\"40478535\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism linking THBS4 to TGF-\\u03b21 pathway activation undefined\", \"In vitro only\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Established THBS4 as a direct binding target whose level tunes fibroblast ECM expression and PI3K/AKT activity in pulmonary fibrosis.\",\n      \"evidence\": \"SPR binding (Rehmannin), siRNA/overexpression in fibroblasts, and bleomycin fibrosis model\",\n      \"pmids\": [\"41202384\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Endogenous receptor mediating fibroblast effects not identified\", \"Single lab\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Showed THBS4 promotes axonal regeneration and limits neuronal apoptosis with associated changes in NF-\\u03baB and ERK signaling.\",\n      \"evidence\": \"siRNA knockdown and AAV overexpression with behavioral, electrophysiological, and ultrastructural readouts in a sciatic nerve transection model\",\n      \"pmids\": [\"41153662\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Pathway assignment based on expression changes, not mechanistic dissection\", \"Receptor in neurons not identified\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Placed THBS4 upstream of PI3K/AKT-mediated renal fibrosis via pathway epistasis.\",\n      \"evidence\": \"UUO and TGF-\\u03b21-stimulated HK2 models with THBS4 knockdown and IGF-1 rescue\",\n      \"pmids\": [\"40765330\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Receptor coupling THBS4 to PI3K/AKT in kidney unknown\", \"Single lab\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Defined a self-reinforcing THBS4\\u2013TGF-\\u03b2/SMAD2 axis induced by hypoxia/HIF-1\\u03b1 and TGF-\\u03b21/SMAD2/p38 MAPK driving pulmonary vascular remodeling.\",\n      \"evidence\": \"Rat PH transcriptomics, PASMC functional assays, in vivo THBS4 silencing, and pathway analysis\",\n      \"pmids\": [\"41873540\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Receptor mediating PASMC effects not identified\", \"Feedback loop mechanism partially defined\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Showed exosome-delivered THBS4 binds endothelial integrin \\u03b12 to activate PI3K/AKT and rescue preeclampsia, extending the integrin \\u03b12 angiogenic mechanism to a therapeutic delivery context.\",\n      \"evidence\": \"Exosome characterization, uptake/migration/tube formation assays, and a rat preeclampsia model with intraplacental injection\",\n      \"pmids\": [\"41878135\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct binding interface not structurally resolved\", \"Single lab\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How THBS4's distinct receptor engagements (Notch1, integrin \\u03b21, integrin \\u03b12) are selected in different tissues, and the structural basis of these interactions, remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model of THBS4 with any receptor\", \"Determinants of context-specific receptor choice unknown\", \"Identity of receptors in fibroblast and neuronal contexts undefined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0048018\", \"supporting_discovery_ids\": [0, 1, 3, 11]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 6]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [2, 5, 12]},\n      {\"term_id\": \"GO:0031012\", \"supporting_discovery_ids\": [7]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [9]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [9]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 1, 3, 7, 11]},\n      {\"term_id\": \"R-HSA-1474244\", \"supporting_discovery_ids\": [7, 8, 13]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [0, 5]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [1, 10, 7]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"NOTCH1\", \"ITGB1\", \"ITGA2\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}