{"gene":"CCL26","run_date":"2026-04-28T17:28:52","timeline":{"discoveries":[{"year":1999,"finding":"CCL26 (eotaxin-3) was identified as a novel CC chemokine that binds exclusively to CCR3, inducing cytosolic Ca2+ mobilization and in vitro chemotaxis of eosinophils; it inhibited 125I-eotaxin binding to eosinophils and acted on CCR3-transfected cell lines, and induced eosinophil accumulation in vivo in cynomolgus monkeys.","method":"Differential display, recombinant protein production, calcium flux assay, chemotaxis assay, competitive radioligand binding, CCR3-transfected cell lines, in vivo injection","journal":"Journal of immunology","confidence":"High","confidence_rationale":"Tier 1–2 — multiple orthogonal methods in a single foundational study, replicated by subsequent work","pmids":["10415065"],"is_preprint":false},{"year":2001,"finding":"NMR solution structure of CCL26 revealed a monomeric protein with an unstructured N-terminus, N-loop, 3(10)-helix turn, three-stranded antiparallel β-sheet, and C-terminal α-helix; backbone dynamics showed large-amplitude motions in the termini and N-loop implicated in CCR3 receptor binding and activation, and a surface groove and β2-β3 turn were identified as important for receptor specificity.","method":"NMR spectroscopy, 15N relaxation dynamics (model-free formalism)","journal":"Biochemistry","confidence":"High","confidence_rationale":"Tier 1 — 3D structure determination with backbone dynamics by NMR","pmids":["11425309"],"is_preprint":false},{"year":2001,"finding":"IL-4-stimulated HUVECs upregulate eotaxin-3 mRNA and protein; eotaxin-3 is both released and expressed on the endothelial cell surface, and surface-associated eotaxin-3 mediates shear-dependent eosinophil transmigration via CCR3 and pertussis-toxin-sensitive Gi protein signaling.","method":"RT-PCR, Western blot, anti-eotaxin-3 antibody blocking, anti-CCR3 antibody blocking, pertussis toxin treatment, laminar flow transmigration assay","journal":"The Journal of experimental medicine","confidence":"High","confidence_rationale":"Tier 2 — reciprocal antibody blocking experiments with functional readout, multiple methods","pmids":["11748272"],"is_preprint":false},{"year":2003,"finding":"CCL26 binds to CCR2 on monocytes and CCR2-transfected cells but, unlike MCP-1/CCL2, does not trigger intracellular calcium mobilization, enzyme release, or ERK phosphorylation; instead it acts as a natural antagonist for CCR2, inhibiting MCP-1-mediated responses, and promotes active repulsion (reverse migration) of monocytes away from an eotaxin-3 gradient via Gi protein-coupled receptors.","method":"Chemotaxis/chemorepulsion assay, Ca2+ mobilization assay, ERK phosphorylation assay, enzyme release assay, CCR2 transfected cells, pertussis toxin treatment, CCR2 antagonist treatment","journal":"Blood","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal functional assays in transfected cells and primary monocytes","pmids":["12689946"],"is_preprint":false},{"year":2004,"finding":"CCL26 also binds to CCR1 and CCR5, acting as a natural antagonist on both receptors by inhibiting chemotaxis, intracellular calcium release, and actin polymerization induced by known CCR1/CCR5 agonists; 3D structural analysis identified two distinct epitopes potentially responsible for binding CCR1, CCR2, CCR3, and CCR5.","method":"Chemotaxis assay, Ca2+ mobilization assay, actin polymerization assay, radioligand binding with CCR1/CCR5-transfected cells, 3D structural analysis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal functional assays in transfected cells, structural analysis","pmids":["15039444"],"is_preprint":false},{"year":2002,"finding":"IL-4 and IL-13 induce CCL26 mRNA expression in primary dermal fibroblasts and lung epithelial cells in a time- and dose-dependent manner; IL-4 is ~100-fold more potent than IL-13; TNF-α alone does not induce expression but acts synergistically with IL-4/IL-13; dexamethasone pre-treatment diminishes CCL26 induction.","method":"Northern hybridization, cytokine stimulation with dose-response and time-course","journal":"Cytokine","confidence":"Medium","confidence_rationale":"Tier 3 — single lab, Northern blot with multiple cytokine conditions","pmids":["12061839"],"is_preprint":false},{"year":2005,"finding":"IL-4 up-regulates CCL26 in keratinocytes (HaCaT cells) through the JAK1/JAK2–STAT6 pathway; serial promoter deletion and mutagenesis identified the proximal STAT6 binding site as the key IL-4 response element; JAK inhibitors suppress CCL26 production in a dose-dependent manner; IL-4 signaling involves the type 2 IL-4 receptor.","method":"RT-PCR, ELISA, promoter deletion/mutagenesis, JAK inhibitors, STAT6 dominant-negative studies","journal":"Clinical and experimental immunology","confidence":"Medium","confidence_rationale":"Tier 2 — promoter mutagenesis and dominant-negative functional studies, single lab","pmids":["16045735"],"is_preprint":false},{"year":2006,"finding":"In airway epithelial cells, CCL26 production induced by TNF-α plus IL-4 is regulated by MEK/ERK (blocked by PD98059/U0126) and p38 MAPK (blocked by SB203580) pathways; unlike eotaxin-1/CCL11, CCL26 production is less sensitive to NF-κB inhibition by proteasome inhibitors.","method":"ELISA, pharmacological inhibitors of MEK, p38, and proteasome in human lung fibroblasts","journal":"Biological & pharmaceutical bulletin","confidence":"Medium","confidence_rationale":"Tier 2 — parallel inhibitor studies distinguishing CCL26 from CCL11 regulation, single lab","pmids":["16755001"],"is_preprint":false},{"year":2006,"finding":"In IL-4-stimulated airway epithelial cells, eotaxin-3/CCL26 is predominantly cell surface bound rather than secreted; cell surface association is partially glycosaminoglycan (GAG) dependent but completely protein dependent, and cell surface-bound eotaxin-3 is critical for eosinophil transepithelial migration via CCR3.","method":"In vitro transepithelial chemotaxis assay, CCR3 antibody blocking, epithelial cell surface localization studies, anti-eotaxin-3 blocking","journal":"European journal of immunology","confidence":"High","confidence_rationale":"Tier 2 — functional migration assay with antibody blocking and surface localization experiments showing mechanistic link","pmids":["16983721"],"is_preprint":false},{"year":2005,"finding":"In A549 alveolar epithelial cells, CCL26 autoregulates its own synthesis via the CCR3 receptor: exogenous CCL26 (but not CCL24) reduces IL-4/IL-13-induced CCL26 secretion and downregulates CCR3 expression by 30-40%; a CCR3-specific antagonist (SB-328437) blocks IL-4-dependent CCL26 synthesis.","method":"ELISA, flow cytometry for CCR3 expression, anti-CCR3 antibody pretreatment, CCR3 antagonist (SB-328437), cycloheximide and actinomycin D experiments","journal":"American journal of physiology. Lung cellular and molecular physiology","confidence":"Medium","confidence_rationale":"Tier 2 — functional autoregulation shown with multiple approaches including receptor antagonist and neutralizing antibody","pmids":["15863444"],"is_preprint":false},{"year":2004,"finding":"IFN-γ has biphasic effects on CCL26 production in bronchial epithelial cells: concurrent IFN-γ inhibits IL-13/IL-4-induced eotaxin-3 by downregulating STAT6 activation, while 2-day pre-treatment with IFN-γ enhances CCL26 production by upregulating IL-4Rα and IL-2Rγ (type 1 IL-4R components).","method":"ELISA, RT-PCR, Western blot for STAT6 phosphorylation, IL-4Rα protein expression in BEAS-2B cells","journal":"American journal of respiratory cell and molecular biology","confidence":"Medium","confidence_rationale":"Tier 2 — multiple methods linking receptor upregulation to enhanced CCL26 production, single lab","pmids":["15231490"],"is_preprint":false},{"year":2010,"finding":"In human monocytes and macrophages, IL-4 induces CCL26 mRNA and protein via STAT6; TNF-α and IL-1β synergize with IL-4 at a step downstream of STAT6 activation; IFN-γ pre-treatment decreases total STAT6 protein, blocks IL-4-mediated STAT6 phosphorylation, and suppresses CCL26 expression.","method":"RT-PCR, ELISA, Western blot for STAT6 phosphorylation in U937 cells, primary monocytes, and monocyte-derived macrophages","journal":"Immunology","confidence":"Medium","confidence_rationale":"Tier 2 — multiple cell types and orthogonal methods, single lab","pmids":["20059579"],"is_preprint":false},{"year":2012,"finding":"IL-4 regulates CCL26 in keratinocytes (HaCaT) via JAK1/JAK2–STAT6: IL-4 activates Stat6 (not Stat3) shown by dominant-negative studies, induces Stat6 nuclear translocation and CCL26 promoter activation; serial 5' deletion and mutagenesis identified the proximal Stat6 site as the key response element.","method":"Promoter deletion, site-directed mutagenesis, dominant-negative STAT constructs, Western blot, ELISA, RT-PCR","journal":"Molecular immunology","confidence":"High","confidence_rationale":"Tier 1 — promoter mutagenesis plus dominant-negative functional validation","pmids":["22226123"],"is_preprint":false},{"year":2012,"finding":"Omeprazole blocks IL-4-stimulated CCL26 expression in esophageal squamous cells by preventing STAT6 binding to the eotaxin-3 promoter; it has no effect on STAT6 phosphorylation or nuclear translocation, but blocks recruitment of STAT6, RNA Pol II, and trimethylated H3K4 to the CCL26 promoter.","method":"ELISA, PCR, Western blot for STAT6 phosphorylation/translocation, reporter construct assay, ChIP assay","journal":"PloS one","confidence":"High","confidence_rationale":"Tier 1 — ChIP assay with multiple chromatin marks plus reporter construct, mechanistically precise","pmids":["23185525"],"is_preprint":false},{"year":2011,"finding":"IL-13-stimulated CCL26 secretion in lung epithelial cells is regulated by atypical PKC (aPKC)–STAT6 signaling; γ-tocotrienol increases expression of PAR4 (endogenous aPKC inhibitor) and enhances aPKC-PAR4 complex formation, thereby blocking IL-13-induced STAT6 phosphorylation/DNA binding and CCL26 generation.","method":"ELISA, siRNA knockdown, pharmacological inhibitors, EMSA (STAT6 DNA binding), Western blot, co-immunoprecipitation of aPKC/PAR4 complex","journal":"The Journal of nutritional biochemistry","confidence":"Medium","confidence_rationale":"Tier 2 — siRNA + inhibitor + co-IP combination, single lab","pmids":["21764283"],"is_preprint":false},{"year":2011,"finding":"STAT6 phosphorylation inhibitor compound (R)-84 directly binds STAT6 and prevents its active dimer formation, thereby inhibiting IL-4-induced eotaxin-3 secretion in bronchial epithelial BEAS-2B cells.","method":"ELISA, STAT6 binding assay, phosphorylation assay in BEAS-2B cells","journal":"Bioorganic & medicinal chemistry","confidence":"Medium","confidence_rationale":"Tier 2 — direct binding to STAT6 with functional readout of CCL26 secretion","pmids":["22217933"],"is_preprint":false},{"year":2011,"finding":"PGD2 and its metabolite 15d-PGJ2 induce eotaxin-3/CCL26 production from sebocytes via peroxisome proliferator-activated receptor gamma (PPARγ), providing a mechanistic pathway linking COX metabolites to eosinophil chemoattractant production in eosinophilic pustular folliculitis.","method":"Immunostaining, ELISA, receptor identification in sebocyte cultures","journal":"The Journal of allergy and clinical immunology","confidence":"Medium","confidence_rationale":"Tier 2 — receptor-ligand pathway identified by PPARγ agonist/antagonist studies, single lab","pmids":["22206772"],"is_preprint":false},{"year":2013,"finding":"In human colonic myofibroblasts, IL-4 and IL-13 enhance CCL26 expression through STAT6-mediated pathways; SOCS1 also participates in regulating IL-4/IL-13-induced CCL26; IFN-γ acts as a negative regulator via STAT1 activation.","method":"RT-PCR, ELISA, Western blot in primary colonic myofibroblasts with cytokine stimulation","journal":"Clinical and experimental immunology","confidence":"Medium","confidence_rationale":"Tier 2 — multiple cytokine pathway regulators identified with mechanistic follow-up, single lab","pmids":["23607908"],"is_preprint":false},{"year":2013,"finding":"CCL26 induces migration and invasion of extravillous trophoblasts (HTR8/SVneo cells) and increases MMP2 activity; it also promotes adhesion to collagen IV and fibronectin without affecting TIMP2 activity.","method":"xCELLigence real-time migration assay, wound-healing assay, Matrigel invasion assay, zymography, reverse zymography, adhesion assay","journal":"Human reproduction","confidence":"Medium","confidence_rationale":"Tier 2 — multiple orthogonal functional assays in a cell line model, single lab","pmids":["23477905"],"is_preprint":false},{"year":2013,"finding":"CCL26 signals through CX3CR1 (in addition to CCR3) on NK cells to induce chemotaxis, cytoskeleton changes, and F-actin reorganization; this signaling is sensitive to genistein (tyrosine kinase inhibitor); allergen challenge increases CX3CR1 expression on NK cells and augments NK cell chemotaxis toward CCL26.","method":"Microchemotaxis chamber, flow cytometry, confocal microscopy, pharmacological inhibition with genistein","journal":"Clinical and experimental allergy","confidence":"Medium","confidence_rationale":"Tier 2 — functional chemotaxis with receptor expression correlated, inhibitor used, single lab","pmids":["23414540"],"is_preprint":false},{"year":2015,"finding":"CCL26 exhibits direct bactericidal activity against airway pathogens (S. pneumoniae, S. aureus, H. influenzae, P. aeruginosa) by membrane disruption; bactericidal activity is concentrated in the cationic/amphipathic C-terminal region. Mast cell chymase and tryptase cleave CCL26 generating an N-terminal fragment with LPS-neutralizing activity and a C-terminal fragment retaining antibacterial activity; neither fragment activates CCR3.","method":"Viable count assay, electron microscopy, bacterial membrane permeabilization assay, mass spectrometry characterization of protease cleavage fragments, LPS neutralization assay","journal":"Allergy","confidence":"High","confidence_rationale":"Tier 1–2 — multiple orthogonal methods including structural characterization of cleavage fragments and functional assays","pmids":["25377782"],"is_preprint":false},{"year":2016,"finding":"IL-13 induces CCL26 expression in sinonasal epithelial cells via activation of a nongastric H+,K+-ATPase (ATP12A); knockdown of ATP12A significantly attenuated IL-13-induced CCL26 expression; PPIs block this pathway and accelerate IL-13-induced CCL26 mRNA decay.","method":"ELISA, Western blot, RT-PCR, intracellular pH imaging, extracellular K+ alteration, siRNA knockdown of ATP12A","journal":"The Journal of allergy and clinical immunology","confidence":"High","confidence_rationale":"Tier 2 — siRNA knockdown with mechanistic follow-up via intracellular pH imaging, replicated in two cell types","pmids":["27717558"],"is_preprint":false},{"year":2019,"finding":"15-lipoxygenase 1 (15LO1) promotes CCL26/eotaxin-3 expression in nasal epithelial cells through ERK activation; 15LO1 knockdown (DsiRNA) or inhibition decreases IL-13-induced ERK phosphorylation and CCL26 expression; ERK inhibition alone similarly reduces CCL26.","method":"DsiRNA knockdown, pharmacological 15LO1 inhibition, ERK inhibitors, ELISA, Western blot, quantitative RT-PCR, immunofluorescence colocalization","journal":"The Journal of allergy and clinical immunology","confidence":"High","confidence_rationale":"Tier 2 — siRNA + inhibitor + rescue approach with mechanistic pathway delineation","pmids":["31301373"],"is_preprint":false},{"year":2018,"finding":"CISH (a SOCS family member) is induced by IL-13 via STAT6 phosphorylation and acts as a negative regulator of IL-13-induced CCL26 production in human lung fibroblasts; loss-of-function (siRNA) increases CCL26, while gain-of-function (overexpression) decreases CCL26.","method":"cDNA microarray, quantitative RT-PCR, ELISA, Western blot, siRNA knockdown, vector overexpression","journal":"Allergology international","confidence":"Medium","confidence_rationale":"Tier 2 — loss- and gain-of-function in same system, single lab","pmids":["30197185"],"is_preprint":false},{"year":2021,"finding":"IL-4 stimulates CCL26 secretion in esophageal squamous cells via ngH+,K+ATPase and an intracellular calcium pathway: IL-4 induces calcium release from the ER and entry via L-type calcium channels, and inhibitors of these channels (verapamil, diltiazem) as well as calcium chelation block CCL26 secretion; omeprazole and verapamil together suppress CCL26 secretion more than either alone.","method":"ELISA, QPCR, Western blot, Fluo-4 calcium fluorescence imaging, pharmacological inhibitors (omeprazole, SCH28080, EGTA-AM, 2-APB, verapamil, diltiazem), RNA-seq of patient biopsies","journal":"Gastroenterology","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal inhibitor approaches with live calcium imaging, confirmed in primary cells and patient biopsies","pmids":["33581123"],"is_preprint":false},{"year":2023,"finding":"Airway epithelial cell-derived CCL26 binds CX3CR1 on CX3CR1+ alveolar macrophages, activating this subset to secrete C1q, which facilitates eosinophil clearance; conditional knockout of CCL26 in airway epithelial cells or depletion of CX3CR1 macrophages delays resolution of allergic lung inflammation and prolongs tissue eosinophilia.","method":"Conditional CCL26 knockout mice, CX3CR1 macrophage depletion, mass cytometry, single-cell RNA sequencing, biophysical and immunological analyses, human allergen bronchoprovocation","journal":"American journal of respiratory and critical care medicine","confidence":"High","confidence_rationale":"Tier 2 — conditional knockout with defined cellular phenotype, multiple orthogonal methods including scRNA-seq and human challenge","pmids":["36790376"],"is_preprint":false},{"year":2010,"finding":"CCL26 (eotaxin-3/CCL26) but not CCL24 promotes migration (chemotaxis) of human lung fibroblasts, while CCL24 but not CCL26 stimulates proliferation and collagen synthesis; neither chemokine induces alpha-smooth muscle actin or TGF-β1 expression, demonstrating differential profibrogenic activities.","method":"3H-thymidine proliferation assay, 3H-hydroxyproline collagen assay, Boyden chamber chemotaxis, immunostaining for alpha-SMA, ELISA for TGF-β1","journal":"Annals of allergy, asthma & immunology","confidence":"Medium","confidence_rationale":"Tier 2 — multiple functional assays distinguishing CCL26 from CCL24 in lung fibroblasts, single lab","pmids":["20143648"],"is_preprint":false},{"year":2003,"finding":"CCR3-mediated CCL26-induced eosinophil degranulation (EPO release) is reduced by specific inhibitors of ERK1/ERK2 (U0126), p38 MAPK (SB203580), and PI3K (LY294002), establishing that all three pathways are downstream of CCR3 activation by CCL26; IL-5 potentiates CCL26-induced degranulation.","method":"Eosinophil peroxidase degranulation assay with pharmacological inhibitors in HL-60 eosinophilic cells","journal":"Immunopharmacology and immunotoxicology","confidence":"Medium","confidence_rationale":"Tier 2 — parallel inhibitor approach mapping downstream signaling, single lab","pmids":["12784909"],"is_preprint":false},{"year":2017,"finding":"PRL-3 upregulates CCL26 expression in colorectal cancer cells; CCL26 binds CCR3 on tumor-associated macrophages, triggering intracellular Ca2+ mobilization and increased IL-6 and IL-8 expression in macrophages, which in turn enhances colorectal cancer cell invasiveness in co-culture.","method":"PRL-3 overexpression/silencing, recombinant CCL26 treatment, co-culture invasion assay, calcium mobilization assay, Western blot, IHC, in vivo mouse xenograft","journal":"Molecular cancer therapeutics","confidence":"Medium","confidence_rationale":"Tier 2 — receptor-ligand mechanism validated in co-culture and in vivo, single lab","pmids":["29051319"],"is_preprint":false}],"current_model":"CCL26 (eotaxin-3) is a secreted CC chemokine that acts primarily as a CCR3 agonist to recruit eosinophils, basophils, and Th2 lymphocytes, but also functions as a natural antagonist at CCR1, CCR2, and CCR5 on monocytes; its expression is induced by IL-4 and IL-13 through a JAK1/JAK2–STAT6 axis (with a key proximal STAT6 promoter element) and is further modulated by a nongastric H+,K+-ATPase/intracellular calcium pathway, 15LO1-ERK signaling, and negative feedback via CISH; surface-associated CCL26 mediates eosinophil transepithelial migration, its C-terminal domain exhibits direct bactericidal activity modulated by mast cell proteases, and it activates CX3CR1 on alveolar macrophages to drive resolution of allergic lung inflammation via C1q-mediated eosinophil clearance."},"narrative":{"teleology":[{"year":1999,"claim":"Identification of CCL26 as a selective CCR3 ligand established that eosinophil recruitment uses a dedicated chemokine–receptor axis distinct from other CC chemokine pathways.","evidence":"Differential display cloning, recombinant protein calcium flux assay, chemotaxis, competitive radioligand binding on CCR3-transfected cells, and in vivo eosinophil accumulation in cynomolgus monkeys","pmids":["10415065"],"confidence":"High","gaps":["No crystal structure of the CCL26–CCR3 complex","In vivo specificity of CCR3-dependence not confirmed by receptor knockout"]},{"year":2001,"claim":"The NMR solution structure revealed a monomeric chemokine fold with flexible N-terminal and N-loop regions implicated in CCR3 activation, providing a structural basis for receptor engagement and specificity.","evidence":"NMR spectroscopy with 15N relaxation dynamics and model-free analysis","pmids":["11425309"],"confidence":"High","gaps":["No co-structure with CCR3","Functional validation of specific residues by mutagenesis not reported in this study"]},{"year":2001,"claim":"Demonstration that surface-associated CCL26 on IL-4-stimulated endothelium drives shear-dependent eosinophil transmigration via CCR3/Gi signaling established a haptotactic mechanism for eosinophil recruitment across vascular barriers.","evidence":"RT-PCR, Western blot, anti-eotaxin-3 and anti-CCR3 antibody blocking, pertussis toxin, laminar flow transmigration assay on HUVECs","pmids":["11748272"],"confidence":"High","gaps":["Identity of surface-anchoring proteins/GAGs not fully resolved","In vivo relevance of surface-bound vs. soluble CCL26 not tested"]},{"year":2002,"claim":"Characterization of IL-4/IL-13 as the primary inducers (with TNF-α synergy and dexamethasone suppression) in fibroblasts and epithelial cells defined the Th2 cytokine dependence of CCL26 transcription.","evidence":"Northern hybridization with dose-response and time-course cytokine stimulation in dermal fibroblasts and lung epithelial cells","pmids":["12061839"],"confidence":"Medium","gaps":["Signaling intermediates not mapped in this study","Promoter elements not identified"]},{"year":2003,"claim":"Discovery that CCL26 acts as a natural antagonist at CCR2 (and later CCR1/CCR5) while being an agonist at CCR3 revealed an unusual dual-function chemokine that simultaneously recruits eosinophils and repels monocytes.","evidence":"Chemotaxis/chemorepulsion, Ca²⁺ mobilization, ERK phosphorylation, enzyme release in monocytes and CCR2/CCR1/CCR5-transfected cells with pertussis toxin and receptor antagonists","pmids":["12689946","15039444"],"confidence":"High","gaps":["Structural basis for agonist vs. antagonist behavior at different receptors not resolved at atomic level","In vivo relevance of monocyte chemorepulsion not demonstrated"]},{"year":2003,"claim":"Mapping CCR3-downstream signaling (ERK1/2, p38 MAPK, PI3K) for CCL26-induced eosinophil degranulation delineated the effector pathways linking receptor engagement to functional eosinophil activation.","evidence":"Eosinophil peroxidase release assay with pharmacological inhibitors in HL-60 eosinophilic cells","pmids":["12784909"],"confidence":"Medium","gaps":["Performed in HL-60 differentiated line, not primary eosinophils","Relative contribution of each pathway not quantified"]},{"year":2005,"claim":"Identification of the proximal STAT6 binding site as the key IL-4 response element in the CCL26 promoter, via JAK1/JAK2–STAT6, established the core transcriptional mechanism for Th2-induced CCL26 expression.","evidence":"Promoter deletion, site-directed mutagenesis, dominant-negative STAT constructs, JAK inhibitors in HaCaT keratinocytes; confirmed and extended in 2012 study","pmids":["16045735","22226123"],"confidence":"High","gaps":["Chromatin accessibility and epigenetic regulation at this locus not characterized beyond H3K4me3 at the time","Cell-type-specific enhancers not mapped"]},{"year":2005,"claim":"The finding that CCL26 autoregulates its own synthesis via CCR3 on epithelial cells revealed a negative feedback loop limiting eosinophil chemoattractant production.","evidence":"ELISA, flow cytometry for CCR3 expression, CCR3 antagonist SB-328437, neutralizing antibody in A549 cells","pmids":["15863444"],"confidence":"Medium","gaps":["Autocrine loop not confirmed in primary airway epithelium","Downstream signaling mediating the negative feedback not identified"]},{"year":2006,"claim":"Demonstration that surface-bound CCL26 on airway epithelial cells is the dominant functional pool driving eosinophil transepithelial migration extended the haptotactic mechanism from endothelium to epithelium.","evidence":"In vitro transepithelial migration assay with anti-eotaxin-3 and anti-CCR3 blocking, surface localization studies in IL-4-stimulated epithelial cells","pmids":["16983721"],"confidence":"High","gaps":["Specific surface-binding proteins not identified","Relative contributions of GAG-dependent vs. protein-dependent anchoring not fully resolved"]},{"year":2012,"claim":"ChIP studies showing omeprazole blocks STAT6, RNA Pol II, and H3K4me3 recruitment to the CCL26 promoter without affecting STAT6 phosphorylation or nuclear translocation revealed a chromatin-level regulatory mechanism for pharmacological suppression of CCL26.","evidence":"ChIP assay, reporter construct, Western blot for STAT6 phosphorylation/translocation in esophageal squamous cells","pmids":["23185525"],"confidence":"High","gaps":["Direct molecular target of omeprazole at the chromatin level not identified","Whether this mechanism operates in vivo in eosinophilic esophagitis tissue not confirmed"]},{"year":2013,"claim":"CCL26 was found to signal through CX3CR1 on NK cells, expanding its receptor repertoire beyond CCR3 and its antagonist targets.","evidence":"Microchemotaxis chamber, flow cytometry for CX3CR1, confocal microscopy, genistein inhibition on human NK cells","pmids":["23414540"],"confidence":"Medium","gaps":["Direct binding affinity to CX3CR1 not measured","Relative physiological importance of CX3CR1 vs. CCR3 signaling unknown"]},{"year":2015,"claim":"Discovery of direct bactericidal activity concentrated in the C-terminal α-helix, with mast cell protease cleavage generating functionally distinct N-terminal (LPS-neutralizing) and C-terminal (bactericidal) fragments, established CCL26 as a bifunctional innate immune effector.","evidence":"Viable count assay, electron microscopy, membrane permeabilization, mass spectrometry of chymase/tryptase cleavage products, LPS neutralization assay","pmids":["25377782"],"confidence":"High","gaps":["In vivo antimicrobial role not demonstrated","Whether protease cleavage occurs at mucosal surfaces in allergic tissue not shown"]},{"year":2016,"claim":"Identification of nongastric H⁺,K⁺-ATPase (ATP12A) as a mediator of IL-13-induced CCL26 expression linked ion transport and intracellular pH to Th2 chemokine regulation.","evidence":"siRNA knockdown of ATP12A, intracellular pH imaging, proton pump inhibitor treatment in sinonasal epithelial cells","pmids":["27717558"],"confidence":"High","gaps":["How intracellular pH changes feed into STAT6 or ERK signaling not resolved","Generalizability beyond sinonasal epithelium not established at that time"]},{"year":2018,"claim":"CISH, induced by IL-13 via STAT6, was identified as a negative-feedback regulator of CCL26 production, connecting SOCS-family signaling to eosinophil chemoattractant control.","evidence":"siRNA knockdown and overexpression of CISH, cDNA microarray, ELISA, Western blot in human lung fibroblasts","pmids":["30197185"],"confidence":"Medium","gaps":["Direct mechanism by which CISH suppresses CCL26 transcription not defined","Not confirmed in epithelial cells or in vivo"]},{"year":2019,"claim":"15-lipoxygenase 1 was shown to promote CCL26 expression via ERK activation, integrating lipid mediator signaling into the transcriptional regulation of this chemokine.","evidence":"DsiRNA knockdown, pharmacological 15LO1 inhibition, ERK inhibitors, ELISA, Western blot in nasal epithelial cells","pmids":["31301373"],"confidence":"High","gaps":["Specific 15LO1 metabolite mediating ERK activation not identified","Interaction with STAT6 pathway not fully delineated"]},{"year":2021,"claim":"IL-4-induced CCL26 secretion was shown to require ER calcium release and L-type calcium channel entry, with pharmacological blockade (verapamil, diltiazem) suppressing CCL26, connecting the ngH⁺,K⁺-ATPase pathway to a defined calcium signaling mechanism.","evidence":"Fluo-4 calcium imaging, pharmacological inhibitors (omeprazole, verapamil, diltiazem, 2-APB, EGTA-AM), ELISA, RNA-seq of patient biopsies in esophageal squamous cells","pmids":["33581123"],"confidence":"High","gaps":["How calcium flux regulates STAT6 promoter occupancy or mRNA stability not defined","Whether calcium channel blockers have therapeutic efficacy in eosinophilic esophagitis not proven"]},{"year":2023,"claim":"Conditional CCL26 knockout in airway epithelial cells demonstrated that CCL26 activates CX3CR1⁺ alveolar macrophages to secrete C1q, driving eosinophil clearance and resolution of allergic lung inflammation — establishing CCL26 as a pro-resolution mediator, not just a pro-inflammatory chemokine.","evidence":"Conditional CCL26 knockout mice, CX3CR1 macrophage depletion, mass cytometry, single-cell RNA-seq, human allergen bronchoprovocation","pmids":["36790376"],"confidence":"High","gaps":["Molecular mechanism of CX3CR1 signaling leading to C1q secretion not defined","Whether this resolution pathway operates in non-pulmonary tissues unknown"]},{"year":null,"claim":"Key unresolved questions include the atomic-resolution structure of CCL26 bound to CCR3 vs. CX3CR1, the structural determinants that switch CCL26 from agonist (CCR3) to antagonist (CCR1/CCR2/CCR5), the in vivo antimicrobial significance of the C-terminal bactericidal domain, and how the calcium/pH and 15LO1–ERK pathways converge with STAT6 at the chromatin level to regulate CCL26 transcription.","evidence":"","pmids":[],"confidence":"Low","gaps":["No co-crystal or cryo-EM structure of CCL26 with any receptor","In vivo antimicrobial function not tested","Integrated signaling model connecting STAT6, ERK, calcium, and 15LO1 pathways at the promoter not available"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0048018","term_label":"receptor ligand activity","supporting_discovery_ids":[0,3,4,28]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[3,4]}],"localization":[{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[0,2,8]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[2,8]}],"pathway":[{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[0,2,8,20,25]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,3,4,19,27,28]}],"complexes":[],"partners":["CCR3","CCR2","CCR1","CCR5","CX3CR1","STAT6"],"other_free_text":[]},"mechanistic_narrative":"CCL26 (eotaxin-3) is a CC chemokine that functions as a selective CCR3 agonist driving eosinophil chemotaxis, degranulation, and transepithelial migration, while simultaneously acting as a natural antagonist at CCR1, CCR2, and CCR5 on monocytes [PMID:10415065, PMID:12689946, PMID:15039444]. Its expression is induced by IL-4 and IL-13 through a JAK1/JAK2–STAT6 axis centered on a proximal STAT6 promoter element, with additional regulation by MEK/ERK, p38 MAPK, nongastric H⁺,K⁺-ATPase/intracellular calcium signaling, 15LO1–ERK signaling, and negative feedback via CISH [PMID:22226123, PMID:27717558, PMID:31301373, PMID:30197185]. Beyond its chemotactic role, CCL26 exhibits direct bactericidal activity through its cationic C-terminal domain—an activity modulated by mast cell chymase and tryptase—and signals through CX3CR1 on alveolar macrophages to promote C1q-mediated eosinophil clearance and resolution of allergic airway inflammation [PMID:25377782, PMID:36790376]. CCL26 also acts on non-immune cells, promoting trophoblast migration and MMP2 activation, fibroblast chemotaxis, and tumor-associated macrophage recruitment via CCR3 in colorectal cancer [PMID:23477905, PMID:20143648, PMID:29051319]."},"prefetch_data":{"uniprot":{"accession":"Q9Y258","full_name":"C-C motif chemokine 26","aliases":["CC chemokine IMAC","Eotaxin-3","Macrophage inflammatory protein 4-alpha","MIP-4-alpha","Small-inducible cytokine A26","Thymic stroma chemokine-1","TSC-1"],"length_aa":94,"mass_kda":10.6,"function":"Chemoattractant for eosinophils and basophils (PubMed:10415065, PubMed:10488147). Acts as a ligand for C-C chemokine receptor CCR3 which triggers Ca(2+) mobilization in eosinophils (PubMed:10415065, PubMed:10488147, PubMed:11425309). Also acts as a ligand for CX3C chemokine receptor CX3CR1, inducing cell chemotaxis (PubMed:20974991)","subcellular_location":"Secreted","url":"https://www.uniprot.org/uniprotkb/Q9Y258/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/CCL26","classification":"Not Classified","n_dependent_lines":18,"n_total_lines":1208,"dependency_fraction":0.014900662251655629},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/CCL26","total_profiled":1310},"omim":[{"mim_id":"610247","title":"ESOPHAGITIS, EOSINOPHILIC, 1; EOE1","url":"https://www.omim.org/entry/610247"},{"mim_id":"604697","title":"CHEMOKINE, CC MOTIF, LIGAND 26; CCL26","url":"https://www.omim.org/entry/604697"},{"mim_id":"601470","title":"CHEMOKINE, CX3C MOTIF, RECEPTOR 1; CX3CR1","url":"https://www.omim.org/entry/601470"},{"mim_id":"600807","title":"ASTHMA, SUSCEPTIBILITY TO","url":"https://www.omim.org/entry/600807"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Group enriched","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"choroid plexus","ntpm":45.8},{"tissue":"ovary","ntpm":22.0},{"tissue":"pituitary gland","ntpm":18.2}],"url":"https://www.proteinatlas.org/search/CCL26"},"hgnc":{"alias_symbol":["MIP-4alpha","eotaxin-3","IMAC","MIP-4a","TSC-1"],"prev_symbol":["SCYA26"]},"alphafold":{"accession":"Q9Y258","domains":[{"cath_id":"2.40.50.40","chopping":"43-94","consensus_level":"medium","plddt":92.9535,"start":43,"end":94}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y258","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y258-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y258-F1-predicted_aligned_error_v6.png","plddt_mean":84.25},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=CCL26","jax_strain_url":"https://www.jax.org/strain/search?query=CCL26"},"sequence":{"accession":"Q9Y258","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9Y258.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9Y258/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y258"}},"corpus_meta":[{"pmid":"22580413","id":"PMC_22580413","title":"Omeprazole blocks eotaxin-3 expression by oesophageal squamous cells from patients with eosinophilic oesophagitis and GORD.","date":"2012","source":"Gut","url":"https://pubmed.ncbi.nlm.nih.gov/22580413","citation_count":275,"is_preprint":false},{"pmid":"19892187","id":"PMC_19892187","title":"Immobilized-metal affinity chromatography (IMAC): a review.","date":"2009","source":"Methods in enzymology","url":"https://pubmed.ncbi.nlm.nih.gov/19892187","citation_count":244,"is_preprint":false},{"pmid":"10415065","id":"PMC_10415065","title":"A novel human CC chemokine, eotaxin-3, which is expressed in IL-4-stimulated vascular endothelial cells, exhibits potent activity toward eosinophils.","date":"1999","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/10415065","citation_count":218,"is_preprint":false},{"pmid":"21884947","id":"PMC_21884947","title":"Clinical and demographic predictors of outcomes in recent onset dilated cardiomyopathy: results of the IMAC (Intervention in Myocarditis and Acute Cardiomyopathy)-2 study.","date":"2011","source":"Journal of the American College of Cardiology","url":"https://pubmed.ncbi.nlm.nih.gov/21884947","citation_count":203,"is_preprint":false},{"pmid":"23185525","id":"PMC_23185525","title":"Omeprazole blocks STAT6 binding to the eotaxin-3 promoter in eosinophilic esophagitis cells.","date":"2012","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/23185525","citation_count":203,"is_preprint":false},{"pmid":"16097752","id":"PMC_16097752","title":"Specificity of immobilized metal affinity-based IMAC/C18 tip enrichment of phosphopeptides for protein phosphorylation analysis.","date":"2005","source":"Analytical chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16097752","citation_count":162,"is_preprint":false},{"pmid":"16396499","id":"PMC_16396499","title":"Phosphoproteomic analysis of rat liver by high capacity IMAC and LC-MS/MS.","date":"2006","source":"Journal of proteome research","url":"https://pubmed.ncbi.nlm.nih.gov/16396499","citation_count":128,"is_preprint":false},{"pmid":"18220336","id":"PMC_18220336","title":"Combining protein-based IMAC, peptide-based IMAC, and MudPIT for efficient phosphoproteomic analysis.","date":"2008","source":"Journal of proteome research","url":"https://pubmed.ncbi.nlm.nih.gov/18220336","citation_count":126,"is_preprint":false},{"pmid":"17208939","id":"PMC_17208939","title":"Mitochondrial phosphoproteome revealed by an improved IMAC method and MS/MS/MS.","date":"2007","source":"Molecular & cellular proteomics : MCP","url":"https://pubmed.ncbi.nlm.nih.gov/17208939","citation_count":124,"is_preprint":false},{"pmid":"25112708","id":"PMC_25112708","title":"Proton pump inhibitor-responsive oesophageal eosinophilia correlates with downregulation of eotaxin-3 and Th2 cytokines overexpression.","date":"2014","source":"Alimentary pharmacology & therapeutics","url":"https://pubmed.ncbi.nlm.nih.gov/25112708","citation_count":122,"is_preprint":false},{"pmid":"31572778","id":"PMC_31572778","title":"PhoX: An IMAC-Enrichable Cross-Linking Reagent.","date":"2019","source":"ACS central science","url":"https://pubmed.ncbi.nlm.nih.gov/31572778","citation_count":108,"is_preprint":false},{"pmid":"14698143","id":"PMC_14698143","title":"Concerted expression of eotaxin-1, eotaxin-2, and eotaxin-3 in human bronchial epithelial cells.","date":"2003","source":"Cellular immunology","url":"https://pubmed.ncbi.nlm.nih.gov/14698143","citation_count":107,"is_preprint":false},{"pmid":"17900656","id":"PMC_17900656","title":"Increased expression of eotaxin-3 distinguishes between eosinophilic esophagitis and gastroesophageal reflux disease.","date":"2007","source":"Human pathology","url":"https://pubmed.ncbi.nlm.nih.gov/17900656","citation_count":101,"is_preprint":false},{"pmid":"18024530","id":"PMC_18024530","title":"SELDI-TOF MS whole serum proteomic profiling with IMAC surface does not reliably detect prostate cancer.","date":"2007","source":"Clinical chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/18024530","citation_count":97,"is_preprint":false},{"pmid":"12689946","id":"PMC_12689946","title":"Eotaxin-3 is a natural antagonist for CCR2 and exerts a repulsive effect on human monocytes.","date":"2003","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/12689946","citation_count":95,"is_preprint":false},{"pmid":"14616792","id":"PMC_14616792","title":"Significant elevation of serum levels of eotaxin-3/CCL26, but not of eotaxin-2/CCL24, in patients with atopic dermatitis: serum eotaxin-3/CCL26 levels reflect the disease activity of atopic dermatitis.","date":"2003","source":"Clinical and experimental immunology","url":"https://pubmed.ncbi.nlm.nih.gov/14616792","citation_count":89,"is_preprint":false},{"pmid":"17991617","id":"PMC_17991617","title":"A novel method to quantify sphingosine 1-phosphate by immobilized metal affinity chromatography (IMAC).","date":"2007","source":"Prostaglandins & other lipid mediators","url":"https://pubmed.ncbi.nlm.nih.gov/17991617","citation_count":88,"is_preprint":false},{"pmid":"20450229","id":"PMC_20450229","title":"Optimized IMAC-IMAC protocol for phosphopeptide recovery from complex biological samples.","date":"2010","source":"Journal of proteome research","url":"https://pubmed.ncbi.nlm.nih.gov/20450229","citation_count":84,"is_preprint":false},{"pmid":"23015684","id":"PMC_23015684","title":"Epithelial eotaxin-2 and eotaxin-3 expression: relation to asthma severity, luminal eosinophilia and age at onset.","date":"2012","source":"Thorax","url":"https://pubmed.ncbi.nlm.nih.gov/23015684","citation_count":83,"is_preprint":false},{"pmid":"25936567","id":"PMC_25936567","title":"Correlation between CCL26 production by human bronchial epithelial cells and airway eosinophils: Involvement in patients with severe eosinophilic asthma.","date":"2015","source":"The Journal of allergy and clinical immunology","url":"https://pubmed.ncbi.nlm.nih.gov/25936567","citation_count":82,"is_preprint":false},{"pmid":"22739041","id":"PMC_22739041","title":"Cancer-associated fibroblasts up-regulate CCL2, CCL26, IL6 and LOXL2 genes related to promotion of cancer progression in hepatocellular carcinoma cells.","date":"2012","source":"Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie","url":"https://pubmed.ncbi.nlm.nih.gov/22739041","citation_count":80,"is_preprint":false},{"pmid":"16045735","id":"PMC_16045735","title":"Interleukin-4 and interleukin-13 enhance CCL26 production in a human keratinocyte cell line, HaCaT cells.","date":"2005","source":"Clinical and experimental immunology","url":"https://pubmed.ncbi.nlm.nih.gov/16045735","citation_count":78,"is_preprint":false},{"pmid":"11748272","id":"PMC_11748272","title":"Shear-dependent eosinophil transmigration on interleukin 4-stimulated endothelial cells: a role for endothelium-associated eotaxin-3.","date":"2001","source":"The Journal of experimental medicine","url":"https://pubmed.ncbi.nlm.nih.gov/11748272","citation_count":78,"is_preprint":false},{"pmid":"21715320","id":"PMC_21715320","title":"Enhancing the identification of phosphopeptides from putative basophilic kinase substrates using Ti (IV) based IMAC enrichment.","date":"2011","source":"Molecular & cellular proteomics : MCP","url":"https://pubmed.ncbi.nlm.nih.gov/21715320","citation_count":77,"is_preprint":false},{"pmid":"15039444","id":"PMC_15039444","title":"Eotaxin-3/CCL26 is a natural antagonist for CC chemokine receptors 1 and 5. A human chemokine with a regulatory role.","date":"2004","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/15039444","citation_count":75,"is_preprint":false},{"pmid":"29449344","id":"PMC_29449344","title":"Defeating Major Contaminants in Fe3+- Immobilized Metal Ion Affinity Chromatography (IMAC) Phosphopeptide Enrichment.","date":"2018","source":"Molecular & cellular proteomics : MCP","url":"https://pubmed.ncbi.nlm.nih.gov/29449344","citation_count":67,"is_preprint":false},{"pmid":"27717558","id":"PMC_27717558","title":"Proton pump inhibitors decrease eotaxin-3/CCL26 expression in patients with chronic rhinosinusitis with nasal polyps: Possible role of the nongastric H,K-ATPase.","date":"2016","source":"The Journal of allergy and clinical immunology","url":"https://pubmed.ncbi.nlm.nih.gov/27717558","citation_count":67,"is_preprint":false},{"pmid":"21266446","id":"PMC_21266446","title":"Eotaxin-3 in Churg-Strauss syndrome: a clinical and immunogenetic study.","date":"2011","source":"Rheumatology (Oxford, England)","url":"https://pubmed.ncbi.nlm.nih.gov/21266446","citation_count":66,"is_preprint":false},{"pmid":"15801813","id":"PMC_15801813","title":"Cell chromatography: separation of different microbial cells using IMAC supermacroporous monolithic columns.","date":"2005","source":"Biotechnology progress","url":"https://pubmed.ncbi.nlm.nih.gov/15801813","citation_count":62,"is_preprint":false},{"pmid":"22226123","id":"PMC_22226123","title":"IL-4 regulates chemokine CCL26 in keratinocytes through the Jak1, 2/Stat6 signal transduction pathway: Implication for atopic dermatitis.","date":"2012","source":"Molecular immunology","url":"https://pubmed.ncbi.nlm.nih.gov/22226123","citation_count":62,"is_preprint":false},{"pmid":"31301373","id":"PMC_31301373","title":"15-Lipoxygenase 1 in nasal polyps promotes CCL26/eotaxin 3 expression through extracellular signal-regulated kinase activation.","date":"2019","source":"The Journal of allergy and clinical immunology","url":"https://pubmed.ncbi.nlm.nih.gov/31301373","citation_count":62,"is_preprint":false},{"pmid":"29051319","id":"PMC_29051319","title":"CCL26 Participates in the PRL-3-Induced Promotion of Colorectal Cancer Invasion by Stimulating Tumor-Associated Macrophage Infiltration.","date":"2017","source":"Molecular cancer therapeutics","url":"https://pubmed.ncbi.nlm.nih.gov/29051319","citation_count":60,"is_preprint":false},{"pmid":"34927332","id":"PMC_34927332","title":"A Membrane-Permeable and Immobilized Metal Affinity Chromatography (IMAC) Enrichable Cross-Linking Reagent to Advance In Vivo Cross-Linking Mass Spectrometry.","date":"2022","source":"Angewandte Chemie (International ed. in English)","url":"https://pubmed.ncbi.nlm.nih.gov/34927332","citation_count":60,"is_preprint":false},{"pmid":"19367720","id":"PMC_19367720","title":"Phosphorylation analysis of primary human T lymphocytes using sequential IMAC and titanium oxide enrichment.","date":"2008","source":"Journal of proteome research","url":"https://pubmed.ncbi.nlm.nih.gov/19367720","citation_count":60,"is_preprint":false},{"pmid":"26247297","id":"PMC_26247297","title":"Complementary IMAC enrichment methods for HLA-associated phosphopeptide identification by mass spectrometry.","date":"2015","source":"Nature protocols","url":"https://pubmed.ncbi.nlm.nih.gov/26247297","citation_count":60,"is_preprint":false},{"pmid":"12061839","id":"PMC_12061839","title":"Regulation of human eotaxin-3/CCL26 expression: modulation by cytokines and glucocorticoids.","date":"2002","source":"Cytokine","url":"https://pubmed.ncbi.nlm.nih.gov/12061839","citation_count":59,"is_preprint":false},{"pmid":"23883806","id":"PMC_23883806","title":"Comparison of the nasal release of IL-4, IL-10, IL-17, CCL13/MCP-4, and CCL26/eotaxin-3 in allergic rhinitis during season and after allergen challenge.","date":"2013","source":"American journal of rhinology & allergy","url":"https://pubmed.ncbi.nlm.nih.gov/23883806","citation_count":56,"is_preprint":false},{"pmid":"20143648","id":"PMC_20143648","title":"Eotaxin-2/CCL24 and eotaxin-3/CCL26 exert differential profibrogenic effects on human lung fibroblasts.","date":"2010","source":"Annals of allergy, asthma & immunology : official publication of the American College of Allergy, Asthma, & Immunology","url":"https://pubmed.ncbi.nlm.nih.gov/20143648","citation_count":51,"is_preprint":false},{"pmid":"19241004","id":"PMC_19241004","title":"Enrichment and characterization of phosphopeptides by immobilized metal affinity chromatography (IMAC) and mass spectrometry.","date":"2009","source":"Methods in molecular biology (Clifton, N.J.)","url":"https://pubmed.ncbi.nlm.nih.gov/19241004","citation_count":49,"is_preprint":false},{"pmid":"22206772","id":"PMC_22206772","title":"PGD2 induces eotaxin-3 via PPARγ from sebocytes: a possible pathogenesis of eosinophilic pustular folliculitis.","date":"2011","source":"The Journal of allergy and clinical immunology","url":"https://pubmed.ncbi.nlm.nih.gov/22206772","citation_count":45,"is_preprint":false},{"pmid":"21985360","id":"PMC_21985360","title":"Up-regulation of CCL11 and CCL26 is associated with activated eosinophils in bullous pemphigoid.","date":"2011","source":"Clinical and experimental immunology","url":"https://pubmed.ncbi.nlm.nih.gov/21985360","citation_count":44,"is_preprint":false},{"pmid":"16470654","id":"PMC_16470654","title":"Quantitation of protein phosphorylation in pregnant rat uteri using stable isotope dimethyl labeling coupled with IMAC.","date":"2006","source":"Proteomics","url":"https://pubmed.ncbi.nlm.nih.gov/16470654","citation_count":43,"is_preprint":false},{"pmid":"15695929","id":"PMC_15695929","title":"Cytokine-stimulated human lung alveolar epithelial cells release eotaxin-2 (CCL24) and eotaxin-3 (CCL26).","date":"2005","source":"Journal of interferon & cytokine research : the official journal of the International Society for Interferon and Cytokine Research","url":"https://pubmed.ncbi.nlm.nih.gov/15695929","citation_count":43,"is_preprint":false},{"pmid":"23870872","id":"PMC_23870872","title":"Purification and characterization of calcium-binding soybean protein hydrolysates by Ca2+/Fe3+ immobilized metal affinity chromatography (IMAC).","date":"2013","source":"Food chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/23870872","citation_count":42,"is_preprint":false},{"pmid":"24988451","id":"PMC_24988451","title":"Proton pump inhibitors decrease eotaxin-3 expression in the proximal esophagus of children with esophageal eosinophilia.","date":"2014","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/24988451","citation_count":42,"is_preprint":false},{"pmid":"33226818","id":"PMC_33226818","title":"Zirconium(IV)-IMAC Revisited: Improved Performance and Phosphoproteome Coverage by Magnetic Microparticles for Phosphopeptide Affinity Enrichment.","date":"2020","source":"Journal of proteome research","url":"https://pubmed.ncbi.nlm.nih.gov/33226818","citation_count":39,"is_preprint":false},{"pmid":"19445472","id":"PMC_19445472","title":"Identification and characteristics of iron-chelating peptides from soybean protein hydrolysates using IMAC-Fe3+.","date":"2009","source":"Journal of agricultural and food chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/19445472","citation_count":39,"is_preprint":false},{"pmid":"28248267","id":"PMC_28248267","title":"Complementary PTM Profiling of Drug Response in Human Gastric Carcinoma by Immunoaffinity and IMAC Methods with Total Proteome Analysis.","date":"2015","source":"Proteomes","url":"https://pubmed.ncbi.nlm.nih.gov/28248267","citation_count":39,"is_preprint":false},{"pmid":"16342239","id":"PMC_16342239","title":"Phosphopeptide detection using automated online IMAC-capillary LC-ESI-MS/MS.","date":"2006","source":"Proteomics","url":"https://pubmed.ncbi.nlm.nih.gov/16342239","citation_count":39,"is_preprint":false},{"pmid":"20236835","id":"PMC_20236835","title":"Analysis of eotaxin 1/CCL11, eotaxin 2/CCL24 and eotaxin 3/CCL26 expression in lesional and non-lesional skin of patients with atopic dermatitis.","date":"2010","source":"Cytokine","url":"https://pubmed.ncbi.nlm.nih.gov/20236835","citation_count":39,"is_preprint":false},{"pmid":"23927012","id":"PMC_23927012","title":"Combination of multistep IMAC enrichment with high-pH reverse phase separation for in-depth phosphoproteomic profiling.","date":"2013","source":"Journal of proteome research","url":"https://pubmed.ncbi.nlm.nih.gov/23927012","citation_count":38,"is_preprint":false},{"pmid":"21210654","id":"PMC_21210654","title":"Quantitative phosphoproteomics studies using stable isotope dimethyl labeling coupled with IMAC-HILIC-nanoLC-MS/MS for estrogen-induced transcriptional regulation.","date":"2011","source":"Journal of proteome research","url":"https://pubmed.ncbi.nlm.nih.gov/21210654","citation_count":37,"is_preprint":false},{"pmid":"16983721","id":"PMC_16983721","title":"Membrane-bound eotaxin-3 mediates eosinophil transepithelial migration in IL-4-stimulated epithelial cells.","date":"2006","source":"European journal of immunology","url":"https://pubmed.ncbi.nlm.nih.gov/16983721","citation_count":36,"is_preprint":false},{"pmid":"11425309","id":"PMC_11425309","title":"NMR solution structure and backbone dynamics of the CC chemokine eotaxin-3.","date":"2001","source":"Biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11425309","citation_count":35,"is_preprint":false},{"pmid":"23414540","id":"PMC_23414540","title":"Novel cooperation between CX3CL1 and CCL26 inducing NK cell chemotaxis via CX3CR1: a possible mechanism for NK cell infiltration of the allergic nasal tissue.","date":"2013","source":"Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology","url":"https://pubmed.ncbi.nlm.nih.gov/23414540","citation_count":34,"is_preprint":false},{"pmid":"17073866","id":"PMC_17073866","title":"Regulatory mechanisms of galectin-9 and eotaxin-3 synthesis in epidermal keratinocytes: possible involvement of galectin-9 in dermal eosinophilia of Th1-polarized skin inflammation.","date":"2006","source":"Allergy","url":"https://pubmed.ncbi.nlm.nih.gov/17073866","citation_count":32,"is_preprint":false},{"pmid":"8954081","id":"PMC_8954081","title":"Human perforin: rapid enrichment by immobilized metal affinity chromatography (IMAC) for whole cell cytotoxicity assays.","date":"1996","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/8954081","citation_count":32,"is_preprint":false},{"pmid":"15863444","id":"PMC_15863444","title":"Autoregulation of CCL26 synthesis and secretion in A549 cells: a possible mechanism by which alveolar epithelial cells modulate airway inflammation.","date":"2005","source":"American journal of physiology. Lung cellular and molecular physiology","url":"https://pubmed.ncbi.nlm.nih.gov/15863444","citation_count":31,"is_preprint":false},{"pmid":"23477905","id":"PMC_23477905","title":"Control of extravillous trophoblast function by the eotaxins CCL11, CCL24 and CCL26.","date":"2013","source":"Human reproduction (Oxford, England)","url":"https://pubmed.ncbi.nlm.nih.gov/23477905","citation_count":30,"is_preprint":false},{"pmid":"17870612","id":"PMC_17870612","title":"Quantitative comparison of IMAC and TiO2 surfaces used in the study of regulated, dynamic protein phosphorylation.","date":"2007","source":"Journal of the American Society for Mass Spectrometry","url":"https://pubmed.ncbi.nlm.nih.gov/17870612","citation_count":30,"is_preprint":false},{"pmid":"24989688","id":"PMC_24989688","title":"Nasal fluid release of eotaxin-3 and eotaxin-2 in persistent sinonasal eosinophilic inflammation.","date":"2014","source":"International forum of allergy & rhinology","url":"https://pubmed.ncbi.nlm.nih.gov/24989688","citation_count":30,"is_preprint":false},{"pmid":"33581123","id":"PMC_33581123","title":"In Esophageal Squamous Cells From Eosinophilic Esophagitis Patients, Th2 Cytokines Increase Eotaxin-3 Secretion Through Effects on Intracellular Calcium and a Non-Gastric Proton Pump.","date":"2021","source":"Gastroenterology","url":"https://pubmed.ncbi.nlm.nih.gov/33581123","citation_count":29,"is_preprint":false},{"pmid":"15231490","id":"PMC_15231490","title":"Upregulation of interleukin-4 receptor by interferon-gamma: enhanced interleukin-4-induced eotaxin-3 production in airway epithelium.","date":"2004","source":"American journal of respiratory cell and molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/15231490","citation_count":29,"is_preprint":false},{"pmid":"21736374","id":"PMC_21736374","title":"Development and application of a phosphoproteomic method using electrostatic repulsion-hydrophilic interaction chromatography (ERLIC), IMAC, and LC-MS/MS analysis to study Marek's Disease Virus infection.","date":"2011","source":"Journal of proteome research","url":"https://pubmed.ncbi.nlm.nih.gov/21736374","citation_count":28,"is_preprint":false},{"pmid":"21764283","id":"PMC_21764283","title":"Vitamin E forms inhibit IL-13/STAT6-induced eotaxin-3 secretion by up-regulation of PAR4, an endogenous inhibitor of atypical PKC in human lung epithelial cells.","date":"2011","source":"The Journal of nutritional biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/21764283","citation_count":27,"is_preprint":false},{"pmid":"32263073","id":"PMC_32263073","title":"Epitope imprinting enhanced IMAC (EI-IMAC) for highly selective purification of His-tagged protein.","date":"2016","source":"Journal of materials chemistry. B","url":"https://pubmed.ncbi.nlm.nih.gov/32263073","citation_count":26,"is_preprint":false},{"pmid":"25377782","id":"PMC_25377782","title":"Eotaxin-3 (CCL26) exerts innate host defense activities that are modulated by mast cell proteases.","date":"2015","source":"Allergy","url":"https://pubmed.ncbi.nlm.nih.gov/25377782","citation_count":26,"is_preprint":false},{"pmid":"30467464","id":"PMC_30467464","title":"Multiple Critical Periods for Rapamycin Treatment to Correct Structural Defects in Tsc-1-Suppressed Brain.","date":"2018","source":"Frontiers in molecular neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/30467464","citation_count":26,"is_preprint":false},{"pmid":"16755001","id":"PMC_16755001","title":"Differential regulation of eotaxin-1/CCL11 and eotaxin-3/CCL26 production by the TNF-alpha and IL-4 stimulated human lung fibroblast.","date":"2006","source":"Biological & pharmaceutical bulletin","url":"https://pubmed.ncbi.nlm.nih.gov/16755001","citation_count":26,"is_preprint":false},{"pmid":"15337854","id":"PMC_15337854","title":"Fatty acids induce chloride permeation in rat liver mitochondria by activation of the inner membrane anion channel (IMAC).","date":"2004","source":"Journal of bioenergetics and biomembranes","url":"https://pubmed.ncbi.nlm.nih.gov/15337854","citation_count":26,"is_preprint":false},{"pmid":"26851086","id":"PMC_26851086","title":"Phosphopeptide enrichment: Development of magnetic solid phase extraction method based on polydopamine coating and Ti(4+)-IMAC.","date":"2016","source":"Analytica chimica acta","url":"https://pubmed.ncbi.nlm.nih.gov/26851086","citation_count":25,"is_preprint":false},{"pmid":"20059579","id":"PMC_20059579","title":"Regulation of eotaxin-3/CCL26 expression in human monocytic cells.","date":"2010","source":"Immunology","url":"https://pubmed.ncbi.nlm.nih.gov/20059579","citation_count":24,"is_preprint":false},{"pmid":"29136822","id":"PMC_29136822","title":"New Ti-IMAC magnetic polymeric nanoparticles for phosphopeptide enrichment from complex real samples.","date":"2017","source":"Talanta","url":"https://pubmed.ncbi.nlm.nih.gov/29136822","citation_count":24,"is_preprint":false},{"pmid":"32154227","id":"PMC_32154227","title":"Thermal Bioprinting Causes Ample Alterations of Expression of LUCAT1, IL6, CCL26, and NRN1L Genes and Massive Phosphorylation of Critical Oncogenic Drug Resistance Pathways in Breast Cancer Cells.","date":"2020","source":"Frontiers in bioengineering and biotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/32154227","citation_count":23,"is_preprint":false},{"pmid":"23607908","id":"PMC_23607908","title":"Regulation of eotaxin-3/CC chemokine ligand 26 expression by T helper type 2 cytokines in human colonic myofibroblasts.","date":"2013","source":"Clinical and experimental immunology","url":"https://pubmed.ncbi.nlm.nih.gov/23607908","citation_count":22,"is_preprint":false},{"pmid":"19701728","id":"PMC_19701728","title":"Evaluation of immobilized metal-ion affinity chromatography (IMAC) as a technique for IgG(1) monoclonal antibodies purification: the effect of chelating ligand and support.","date":"2009","source":"Applied biochemistry and biotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/19701728","citation_count":22,"is_preprint":false},{"pmid":"25530546","id":"PMC_25530546","title":"Puerarin attenuates airway inflammation by regulation of eotaxin-3.","date":"2014","source":"Immunology letters","url":"https://pubmed.ncbi.nlm.nih.gov/25530546","citation_count":21,"is_preprint":false},{"pmid":"31151084","id":"PMC_31151084","title":"CCL26 and CCR3 are associated with the acute inflammatory response in the CNS in experimental autoimmune encephalomyelitis.","date":"2019","source":"Journal of neuroimmunology","url":"https://pubmed.ncbi.nlm.nih.gov/31151084","citation_count":21,"is_preprint":false},{"pmid":"24924211","id":"PMC_24924211","title":"The impact of immobilized metal affinity chromatography (IMAC) resins on DNA aptamer selection.","date":"2014","source":"Analytical and bioanalytical chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/24924211","citation_count":19,"is_preprint":false},{"pmid":"28212269","id":"PMC_28212269","title":"Separation and Characterization of Angiotensin I Converting Enzyme (ACE) Inhibitory Peptides from Saurida elongata Proteins Hydrolysate by IMAC-Ni2.","date":"2017","source":"Marine drugs","url":"https://pubmed.ncbi.nlm.nih.gov/28212269","citation_count":19,"is_preprint":false},{"pmid":"22217933","id":"PMC_22217933","title":"STAT6 phosphorylation inhibitors block eotaxin-3 secretion in bronchial epithelial cells.","date":"2011","source":"Bioorganic & medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/22217933","citation_count":19,"is_preprint":false},{"pmid":"23924207","id":"PMC_23924207","title":"IMAC fractionation in combination with LC-MS reveals H2B and NIF-1 peptides as potential bladder cancer biomarkers.","date":"2013","source":"Journal of proteome research","url":"https://pubmed.ncbi.nlm.nih.gov/23924207","citation_count":18,"is_preprint":false},{"pmid":"23172588","id":"PMC_23172588","title":"Comparative analysis of salt-responsive phosphoproteins in maize leaves using Ti(4+)--IMAC enrichment and ESI-Q-TOF MS.","date":"2013","source":"Electrophoresis","url":"https://pubmed.ncbi.nlm.nih.gov/23172588","citation_count":18,"is_preprint":false},{"pmid":"30197185","id":"PMC_30197185","title":"CISH is a negative regulator of IL-13-induced CCL26 production in lung fibroblasts.","date":"2018","source":"Allergology international : official journal of the Japanese Society of Allergology","url":"https://pubmed.ncbi.nlm.nih.gov/30197185","citation_count":17,"is_preprint":false},{"pmid":"16264039","id":"PMC_16264039","title":"dsRNA enhances eotaxin-3 production through interleukin-4 receptor upregulation in airway epithelial cells.","date":"2005","source":"The European respiratory journal","url":"https://pubmed.ncbi.nlm.nih.gov/16264039","citation_count":17,"is_preprint":false},{"pmid":"36790376","id":"PMC_36790376","title":"CX3CR1+ Macrophage Facilitates the Resolution of Allergic Lung Inflammation via Interacting CCL26.","date":"2023","source":"American journal of respiratory and critical care medicine","url":"https://pubmed.ncbi.nlm.nih.gov/36790376","citation_count":16,"is_preprint":false},{"pmid":"33764366","id":"PMC_33764366","title":"CCL26 is upregulated by nab-paclitaxel in pancreatic cancer-associated fibroblasts and promotes PDAC invasiveness through activation of the PI3K/AKT/mTOR pathway.","date":"2021","source":"Acta biochimica et biophysica Sinica","url":"https://pubmed.ncbi.nlm.nih.gov/33764366","citation_count":16,"is_preprint":false},{"pmid":"27845745","id":"PMC_27845745","title":"Procyanidin A2 Modulates IL-4-Induced CCL26 Production in Human Alveolar Epithelial Cells.","date":"2016","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/27845745","citation_count":16,"is_preprint":false},{"pmid":"22952702","id":"PMC_22952702","title":"Leukotriene D4 and interleukin-13 cooperate to increase the release of eotaxin-3 by airway epithelial cells.","date":"2012","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/22952702","citation_count":16,"is_preprint":false},{"pmid":"8642196","id":"PMC_8642196","title":"Fractionation of perforin and granzymes by immobilized metal affinity chromatography (IMAC).","date":"1996","source":"Journal of immunological methods","url":"https://pubmed.ncbi.nlm.nih.gov/8642196","citation_count":16,"is_preprint":false},{"pmid":"27010397","id":"PMC_27010397","title":"PLAG (1-Palmitoyl-2-Linoleoyl-3-Acetyl-rac-Glycerol) Modulates Eosinophil Chemotaxis by Regulating CCL26 Expression from Epithelial Cells.","date":"2016","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/27010397","citation_count":16,"is_preprint":false},{"pmid":"11796173","id":"PMC_11796173","title":"A recombinant envelope protein from Dengue virus purified by IMAC is bioequivalent with its immune-affinity chromatography purified counterpart.","date":"2002","source":"Journal of biotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/11796173","citation_count":15,"is_preprint":false},{"pmid":"37195130","id":"PMC_37195130","title":"ATP-Coated Dual-Functionalized Titanium(IV) IMAC Material for Simultaneous Enrichment and Separation of Glycopeptides and Phosphopeptides.","date":"2023","source":"Journal of proteome research","url":"https://pubmed.ncbi.nlm.nih.gov/37195130","citation_count":14,"is_preprint":false},{"pmid":"24275639","id":"PMC_24275639","title":"Purification of a recombinant human growth hormone by an integrated IMAC procedure.","date":"2013","source":"Protein expression and purification","url":"https://pubmed.ncbi.nlm.nih.gov/24275639","citation_count":14,"is_preprint":false},{"pmid":"19350626","id":"PMC_19350626","title":"Separation of hexahistidine fusion proteins with immobilized metal ion affinity chromatographic (IMAC) sorbents derived from M(N+)-tacn and its derivatives.","date":"2009","source":"Biotechnology and bioengineering","url":"https://pubmed.ncbi.nlm.nih.gov/19350626","citation_count":14,"is_preprint":false},{"pmid":"30796548","id":"PMC_30796548","title":"The proteolytic effect of mast cell tryptase to eotaxin-1/CCL11·eotaxin-2/CCL24 and eotaxin-3/CCL26 produced by conjunctival fibroblasts.","date":"2019","source":"Japanese journal of ophthalmology","url":"https://pubmed.ncbi.nlm.nih.gov/30796548","citation_count":14,"is_preprint":false},{"pmid":"17472361","id":"PMC_17472361","title":"Characterization of phosphorylation sites on Tpl2 using IMAC enrichment and a linear ion trap mass spectrometer.","date":"2007","source":"Journal of proteome research","url":"https://pubmed.ncbi.nlm.nih.gov/17472361","citation_count":14,"is_preprint":false},{"pmid":"12784909","id":"PMC_12784909","title":"Inhibition of CCL11, CCL24, and CCL26-induced degranulation in HL-60 eosinophilic cells by specific inhibitors of MEK1/MEK2, p38 MAP kinase, and PI 3-kinase.","date":"2003","source":"Immunopharmacology and immunotoxicology","url":"https://pubmed.ncbi.nlm.nih.gov/12784909","citation_count":14,"is_preprint":false},{"pmid":"38608839","id":"PMC_38608839","title":"TIMAHAC: Streamlined Tandem IMAC-HILIC Workflow for Simultaneous and High-Throughput Plant Phosphoproteomics and N-glycoproteomics.","date":"2024","source":"Molecular & cellular proteomics : MCP","url":"https://pubmed.ncbi.nlm.nih.gov/38608839","citation_count":13,"is_preprint":false},{"pmid":"27057079","id":"PMC_27057079","title":"The Correlation of Serums CCL11, CCL17, CCL26, and CCL27 and Disease Severity in Patients with Urticaria.","date":"2016","source":"Disease markers","url":"https://pubmed.ncbi.nlm.nih.gov/27057079","citation_count":13,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":54992,"output_tokens":7085,"usd":0.135626},"stage2":{"model":"claude-opus-4-6","input_tokens":10833,"output_tokens":4097,"usd":0.234885},"total_usd":0.370511,"stage1_batch_id":"msgbatch_011kfMfE81o6CTcyhVUqumuW","stage2_batch_id":"msgbatch_01DTputS6WNkH745x1nVSoBo","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1999,\n      \"finding\": \"CCL26 (eotaxin-3) was identified as a novel CC chemokine that binds exclusively to CCR3, inducing cytosolic Ca2+ mobilization and in vitro chemotaxis of eosinophils; it inhibited 125I-eotaxin binding to eosinophils and acted on CCR3-transfected cell lines, and induced eosinophil accumulation in vivo in cynomolgus monkeys.\",\n      \"method\": \"Differential display, recombinant protein production, calcium flux assay, chemotaxis assay, competitive radioligand binding, CCR3-transfected cell lines, in vivo injection\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — multiple orthogonal methods in a single foundational study, replicated by subsequent work\",\n      \"pmids\": [\"10415065\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"NMR solution structure of CCL26 revealed a monomeric protein with an unstructured N-terminus, N-loop, 3(10)-helix turn, three-stranded antiparallel β-sheet, and C-terminal α-helix; backbone dynamics showed large-amplitude motions in the termini and N-loop implicated in CCR3 receptor binding and activation, and a surface groove and β2-β3 turn were identified as important for receptor specificity.\",\n      \"method\": \"NMR spectroscopy, 15N relaxation dynamics (model-free formalism)\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — 3D structure determination with backbone dynamics by NMR\",\n      \"pmids\": [\"11425309\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"IL-4-stimulated HUVECs upregulate eotaxin-3 mRNA and protein; eotaxin-3 is both released and expressed on the endothelial cell surface, and surface-associated eotaxin-3 mediates shear-dependent eosinophil transmigration via CCR3 and pertussis-toxin-sensitive Gi protein signaling.\",\n      \"method\": \"RT-PCR, Western blot, anti-eotaxin-3 antibody blocking, anti-CCR3 antibody blocking, pertussis toxin treatment, laminar flow transmigration assay\",\n      \"journal\": \"The Journal of experimental medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal antibody blocking experiments with functional readout, multiple methods\",\n      \"pmids\": [\"11748272\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"CCL26 binds to CCR2 on monocytes and CCR2-transfected cells but, unlike MCP-1/CCL2, does not trigger intracellular calcium mobilization, enzyme release, or ERK phosphorylation; instead it acts as a natural antagonist for CCR2, inhibiting MCP-1-mediated responses, and promotes active repulsion (reverse migration) of monocytes away from an eotaxin-3 gradient via Gi protein-coupled receptors.\",\n      \"method\": \"Chemotaxis/chemorepulsion assay, Ca2+ mobilization assay, ERK phosphorylation assay, enzyme release assay, CCR2 transfected cells, pertussis toxin treatment, CCR2 antagonist treatment\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal functional assays in transfected cells and primary monocytes\",\n      \"pmids\": [\"12689946\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"CCL26 also binds to CCR1 and CCR5, acting as a natural antagonist on both receptors by inhibiting chemotaxis, intracellular calcium release, and actin polymerization induced by known CCR1/CCR5 agonists; 3D structural analysis identified two distinct epitopes potentially responsible for binding CCR1, CCR2, CCR3, and CCR5.\",\n      \"method\": \"Chemotaxis assay, Ca2+ mobilization assay, actin polymerization assay, radioligand binding with CCR1/CCR5-transfected cells, 3D structural analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal functional assays in transfected cells, structural analysis\",\n      \"pmids\": [\"15039444\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"IL-4 and IL-13 induce CCL26 mRNA expression in primary dermal fibroblasts and lung epithelial cells in a time- and dose-dependent manner; IL-4 is ~100-fold more potent than IL-13; TNF-α alone does not induce expression but acts synergistically with IL-4/IL-13; dexamethasone pre-treatment diminishes CCL26 induction.\",\n      \"method\": \"Northern hybridization, cytokine stimulation with dose-response and time-course\",\n      \"journal\": \"Cytokine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — single lab, Northern blot with multiple cytokine conditions\",\n      \"pmids\": [\"12061839\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"IL-4 up-regulates CCL26 in keratinocytes (HaCaT cells) through the JAK1/JAK2–STAT6 pathway; serial promoter deletion and mutagenesis identified the proximal STAT6 binding site as the key IL-4 response element; JAK inhibitors suppress CCL26 production in a dose-dependent manner; IL-4 signaling involves the type 2 IL-4 receptor.\",\n      \"method\": \"RT-PCR, ELISA, promoter deletion/mutagenesis, JAK inhibitors, STAT6 dominant-negative studies\",\n      \"journal\": \"Clinical and experimental immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — promoter mutagenesis and dominant-negative functional studies, single lab\",\n      \"pmids\": [\"16045735\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"In airway epithelial cells, CCL26 production induced by TNF-α plus IL-4 is regulated by MEK/ERK (blocked by PD98059/U0126) and p38 MAPK (blocked by SB203580) pathways; unlike eotaxin-1/CCL11, CCL26 production is less sensitive to NF-κB inhibition by proteasome inhibitors.\",\n      \"method\": \"ELISA, pharmacological inhibitors of MEK, p38, and proteasome in human lung fibroblasts\",\n      \"journal\": \"Biological & pharmaceutical bulletin\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — parallel inhibitor studies distinguishing CCL26 from CCL11 regulation, single lab\",\n      \"pmids\": [\"16755001\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"In IL-4-stimulated airway epithelial cells, eotaxin-3/CCL26 is predominantly cell surface bound rather than secreted; cell surface association is partially glycosaminoglycan (GAG) dependent but completely protein dependent, and cell surface-bound eotaxin-3 is critical for eosinophil transepithelial migration via CCR3.\",\n      \"method\": \"In vitro transepithelial chemotaxis assay, CCR3 antibody blocking, epithelial cell surface localization studies, anti-eotaxin-3 blocking\",\n      \"journal\": \"European journal of immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — functional migration assay with antibody blocking and surface localization experiments showing mechanistic link\",\n      \"pmids\": [\"16983721\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"In A549 alveolar epithelial cells, CCL26 autoregulates its own synthesis via the CCR3 receptor: exogenous CCL26 (but not CCL24) reduces IL-4/IL-13-induced CCL26 secretion and downregulates CCR3 expression by 30-40%; a CCR3-specific antagonist (SB-328437) blocks IL-4-dependent CCL26 synthesis.\",\n      \"method\": \"ELISA, flow cytometry for CCR3 expression, anti-CCR3 antibody pretreatment, CCR3 antagonist (SB-328437), cycloheximide and actinomycin D experiments\",\n      \"journal\": \"American journal of physiology. Lung cellular and molecular physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — functional autoregulation shown with multiple approaches including receptor antagonist and neutralizing antibody\",\n      \"pmids\": [\"15863444\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"IFN-γ has biphasic effects on CCL26 production in bronchial epithelial cells: concurrent IFN-γ inhibits IL-13/IL-4-induced eotaxin-3 by downregulating STAT6 activation, while 2-day pre-treatment with IFN-γ enhances CCL26 production by upregulating IL-4Rα and IL-2Rγ (type 1 IL-4R components).\",\n      \"method\": \"ELISA, RT-PCR, Western blot for STAT6 phosphorylation, IL-4Rα protein expression in BEAS-2B cells\",\n      \"journal\": \"American journal of respiratory cell and molecular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple methods linking receptor upregulation to enhanced CCL26 production, single lab\",\n      \"pmids\": [\"15231490\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"In human monocytes and macrophages, IL-4 induces CCL26 mRNA and protein via STAT6; TNF-α and IL-1β synergize with IL-4 at a step downstream of STAT6 activation; IFN-γ pre-treatment decreases total STAT6 protein, blocks IL-4-mediated STAT6 phosphorylation, and suppresses CCL26 expression.\",\n      \"method\": \"RT-PCR, ELISA, Western blot for STAT6 phosphorylation in U937 cells, primary monocytes, and monocyte-derived macrophages\",\n      \"journal\": \"Immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple cell types and orthogonal methods, single lab\",\n      \"pmids\": [\"20059579\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"IL-4 regulates CCL26 in keratinocytes (HaCaT) via JAK1/JAK2–STAT6: IL-4 activates Stat6 (not Stat3) shown by dominant-negative studies, induces Stat6 nuclear translocation and CCL26 promoter activation; serial 5' deletion and mutagenesis identified the proximal Stat6 site as the key response element.\",\n      \"method\": \"Promoter deletion, site-directed mutagenesis, dominant-negative STAT constructs, Western blot, ELISA, RT-PCR\",\n      \"journal\": \"Molecular immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — promoter mutagenesis plus dominant-negative functional validation\",\n      \"pmids\": [\"22226123\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Omeprazole blocks IL-4-stimulated CCL26 expression in esophageal squamous cells by preventing STAT6 binding to the eotaxin-3 promoter; it has no effect on STAT6 phosphorylation or nuclear translocation, but blocks recruitment of STAT6, RNA Pol II, and trimethylated H3K4 to the CCL26 promoter.\",\n      \"method\": \"ELISA, PCR, Western blot for STAT6 phosphorylation/translocation, reporter construct assay, ChIP assay\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — ChIP assay with multiple chromatin marks plus reporter construct, mechanistically precise\",\n      \"pmids\": [\"23185525\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"IL-13-stimulated CCL26 secretion in lung epithelial cells is regulated by atypical PKC (aPKC)–STAT6 signaling; γ-tocotrienol increases expression of PAR4 (endogenous aPKC inhibitor) and enhances aPKC-PAR4 complex formation, thereby blocking IL-13-induced STAT6 phosphorylation/DNA binding and CCL26 generation.\",\n      \"method\": \"ELISA, siRNA knockdown, pharmacological inhibitors, EMSA (STAT6 DNA binding), Western blot, co-immunoprecipitation of aPKC/PAR4 complex\",\n      \"journal\": \"The Journal of nutritional biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — siRNA + inhibitor + co-IP combination, single lab\",\n      \"pmids\": [\"21764283\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"STAT6 phosphorylation inhibitor compound (R)-84 directly binds STAT6 and prevents its active dimer formation, thereby inhibiting IL-4-induced eotaxin-3 secretion in bronchial epithelial BEAS-2B cells.\",\n      \"method\": \"ELISA, STAT6 binding assay, phosphorylation assay in BEAS-2B cells\",\n      \"journal\": \"Bioorganic & medicinal chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct binding to STAT6 with functional readout of CCL26 secretion\",\n      \"pmids\": [\"22217933\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"PGD2 and its metabolite 15d-PGJ2 induce eotaxin-3/CCL26 production from sebocytes via peroxisome proliferator-activated receptor gamma (PPARγ), providing a mechanistic pathway linking COX metabolites to eosinophil chemoattractant production in eosinophilic pustular folliculitis.\",\n      \"method\": \"Immunostaining, ELISA, receptor identification in sebocyte cultures\",\n      \"journal\": \"The Journal of allergy and clinical immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — receptor-ligand pathway identified by PPARγ agonist/antagonist studies, single lab\",\n      \"pmids\": [\"22206772\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"In human colonic myofibroblasts, IL-4 and IL-13 enhance CCL26 expression through STAT6-mediated pathways; SOCS1 also participates in regulating IL-4/IL-13-induced CCL26; IFN-γ acts as a negative regulator via STAT1 activation.\",\n      \"method\": \"RT-PCR, ELISA, Western blot in primary colonic myofibroblasts with cytokine stimulation\",\n      \"journal\": \"Clinical and experimental immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple cytokine pathway regulators identified with mechanistic follow-up, single lab\",\n      \"pmids\": [\"23607908\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"CCL26 induces migration and invasion of extravillous trophoblasts (HTR8/SVneo cells) and increases MMP2 activity; it also promotes adhesion to collagen IV and fibronectin without affecting TIMP2 activity.\",\n      \"method\": \"xCELLigence real-time migration assay, wound-healing assay, Matrigel invasion assay, zymography, reverse zymography, adhesion assay\",\n      \"journal\": \"Human reproduction\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal functional assays in a cell line model, single lab\",\n      \"pmids\": [\"23477905\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"CCL26 signals through CX3CR1 (in addition to CCR3) on NK cells to induce chemotaxis, cytoskeleton changes, and F-actin reorganization; this signaling is sensitive to genistein (tyrosine kinase inhibitor); allergen challenge increases CX3CR1 expression on NK cells and augments NK cell chemotaxis toward CCL26.\",\n      \"method\": \"Microchemotaxis chamber, flow cytometry, confocal microscopy, pharmacological inhibition with genistein\",\n      \"journal\": \"Clinical and experimental allergy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — functional chemotaxis with receptor expression correlated, inhibitor used, single lab\",\n      \"pmids\": [\"23414540\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"CCL26 exhibits direct bactericidal activity against airway pathogens (S. pneumoniae, S. aureus, H. influenzae, P. aeruginosa) by membrane disruption; bactericidal activity is concentrated in the cationic/amphipathic C-terminal region. Mast cell chymase and tryptase cleave CCL26 generating an N-terminal fragment with LPS-neutralizing activity and a C-terminal fragment retaining antibacterial activity; neither fragment activates CCR3.\",\n      \"method\": \"Viable count assay, electron microscopy, bacterial membrane permeabilization assay, mass spectrometry characterization of protease cleavage fragments, LPS neutralization assay\",\n      \"journal\": \"Allergy\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — multiple orthogonal methods including structural characterization of cleavage fragments and functional assays\",\n      \"pmids\": [\"25377782\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"IL-13 induces CCL26 expression in sinonasal epithelial cells via activation of a nongastric H+,K+-ATPase (ATP12A); knockdown of ATP12A significantly attenuated IL-13-induced CCL26 expression; PPIs block this pathway and accelerate IL-13-induced CCL26 mRNA decay.\",\n      \"method\": \"ELISA, Western blot, RT-PCR, intracellular pH imaging, extracellular K+ alteration, siRNA knockdown of ATP12A\",\n      \"journal\": \"The Journal of allergy and clinical immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — siRNA knockdown with mechanistic follow-up via intracellular pH imaging, replicated in two cell types\",\n      \"pmids\": [\"27717558\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"15-lipoxygenase 1 (15LO1) promotes CCL26/eotaxin-3 expression in nasal epithelial cells through ERK activation; 15LO1 knockdown (DsiRNA) or inhibition decreases IL-13-induced ERK phosphorylation and CCL26 expression; ERK inhibition alone similarly reduces CCL26.\",\n      \"method\": \"DsiRNA knockdown, pharmacological 15LO1 inhibition, ERK inhibitors, ELISA, Western blot, quantitative RT-PCR, immunofluorescence colocalization\",\n      \"journal\": \"The Journal of allergy and clinical immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — siRNA + inhibitor + rescue approach with mechanistic pathway delineation\",\n      \"pmids\": [\"31301373\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"CISH (a SOCS family member) is induced by IL-13 via STAT6 phosphorylation and acts as a negative regulator of IL-13-induced CCL26 production in human lung fibroblasts; loss-of-function (siRNA) increases CCL26, while gain-of-function (overexpression) decreases CCL26.\",\n      \"method\": \"cDNA microarray, quantitative RT-PCR, ELISA, Western blot, siRNA knockdown, vector overexpression\",\n      \"journal\": \"Allergology international\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — loss- and gain-of-function in same system, single lab\",\n      \"pmids\": [\"30197185\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"IL-4 stimulates CCL26 secretion in esophageal squamous cells via ngH+,K+ATPase and an intracellular calcium pathway: IL-4 induces calcium release from the ER and entry via L-type calcium channels, and inhibitors of these channels (verapamil, diltiazem) as well as calcium chelation block CCL26 secretion; omeprazole and verapamil together suppress CCL26 secretion more than either alone.\",\n      \"method\": \"ELISA, QPCR, Western blot, Fluo-4 calcium fluorescence imaging, pharmacological inhibitors (omeprazole, SCH28080, EGTA-AM, 2-APB, verapamil, diltiazem), RNA-seq of patient biopsies\",\n      \"journal\": \"Gastroenterology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal inhibitor approaches with live calcium imaging, confirmed in primary cells and patient biopsies\",\n      \"pmids\": [\"33581123\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Airway epithelial cell-derived CCL26 binds CX3CR1 on CX3CR1+ alveolar macrophages, activating this subset to secrete C1q, which facilitates eosinophil clearance; conditional knockout of CCL26 in airway epithelial cells or depletion of CX3CR1 macrophages delays resolution of allergic lung inflammation and prolongs tissue eosinophilia.\",\n      \"method\": \"Conditional CCL26 knockout mice, CX3CR1 macrophage depletion, mass cytometry, single-cell RNA sequencing, biophysical and immunological analyses, human allergen bronchoprovocation\",\n      \"journal\": \"American journal of respiratory and critical care medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — conditional knockout with defined cellular phenotype, multiple orthogonal methods including scRNA-seq and human challenge\",\n      \"pmids\": [\"36790376\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"CCL26 (eotaxin-3/CCL26) but not CCL24 promotes migration (chemotaxis) of human lung fibroblasts, while CCL24 but not CCL26 stimulates proliferation and collagen synthesis; neither chemokine induces alpha-smooth muscle actin or TGF-β1 expression, demonstrating differential profibrogenic activities.\",\n      \"method\": \"3H-thymidine proliferation assay, 3H-hydroxyproline collagen assay, Boyden chamber chemotaxis, immunostaining for alpha-SMA, ELISA for TGF-β1\",\n      \"journal\": \"Annals of allergy, asthma & immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple functional assays distinguishing CCL26 from CCL24 in lung fibroblasts, single lab\",\n      \"pmids\": [\"20143648\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"CCR3-mediated CCL26-induced eosinophil degranulation (EPO release) is reduced by specific inhibitors of ERK1/ERK2 (U0126), p38 MAPK (SB203580), and PI3K (LY294002), establishing that all three pathways are downstream of CCR3 activation by CCL26; IL-5 potentiates CCL26-induced degranulation.\",\n      \"method\": \"Eosinophil peroxidase degranulation assay with pharmacological inhibitors in HL-60 eosinophilic cells\",\n      \"journal\": \"Immunopharmacology and immunotoxicology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — parallel inhibitor approach mapping downstream signaling, single lab\",\n      \"pmids\": [\"12784909\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"PRL-3 upregulates CCL26 expression in colorectal cancer cells; CCL26 binds CCR3 on tumor-associated macrophages, triggering intracellular Ca2+ mobilization and increased IL-6 and IL-8 expression in macrophages, which in turn enhances colorectal cancer cell invasiveness in co-culture.\",\n      \"method\": \"PRL-3 overexpression/silencing, recombinant CCL26 treatment, co-culture invasion assay, calcium mobilization assay, Western blot, IHC, in vivo mouse xenograft\",\n      \"journal\": \"Molecular cancer therapeutics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — receptor-ligand mechanism validated in co-culture and in vivo, single lab\",\n      \"pmids\": [\"29051319\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"CCL26 (eotaxin-3) is a secreted CC chemokine that acts primarily as a CCR3 agonist to recruit eosinophils, basophils, and Th2 lymphocytes, but also functions as a natural antagonist at CCR1, CCR2, and CCR5 on monocytes; its expression is induced by IL-4 and IL-13 through a JAK1/JAK2–STAT6 axis (with a key proximal STAT6 promoter element) and is further modulated by a nongastric H+,K+-ATPase/intracellular calcium pathway, 15LO1-ERK signaling, and negative feedback via CISH; surface-associated CCL26 mediates eosinophil transepithelial migration, its C-terminal domain exhibits direct bactericidal activity modulated by mast cell proteases, and it activates CX3CR1 on alveolar macrophages to drive resolution of allergic lung inflammation via C1q-mediated eosinophil clearance.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"CCL26 (eotaxin-3) is a CC chemokine that functions as a selective CCR3 agonist driving eosinophil chemotaxis, degranulation, and transepithelial migration, while simultaneously acting as a natural antagonist at CCR1, CCR2, and CCR5 on monocytes [PMID:10415065, PMID:12689946, PMID:15039444]. Its expression is induced by IL-4 and IL-13 through a JAK1/JAK2–STAT6 axis centered on a proximal STAT6 promoter element, with additional regulation by MEK/ERK, p38 MAPK, nongastric H⁺,K⁺-ATPase/intracellular calcium signaling, 15LO1–ERK signaling, and negative feedback via CISH [PMID:22226123, PMID:27717558, PMID:31301373, PMID:30197185]. Beyond its chemotactic role, CCL26 exhibits direct bactericidal activity through its cationic C-terminal domain—an activity modulated by mast cell chymase and tryptase—and signals through CX3CR1 on alveolar macrophages to promote C1q-mediated eosinophil clearance and resolution of allergic airway inflammation [PMID:25377782, PMID:36790376]. CCL26 also acts on non-immune cells, promoting trophoblast migration and MMP2 activation, fibroblast chemotaxis, and tumor-associated macrophage recruitment via CCR3 in colorectal cancer [PMID:23477905, PMID:20143648, PMID:29051319].\",\n  \"teleology\": [\n    {\n      \"year\": 1999,\n      \"claim\": \"Identification of CCL26 as a selective CCR3 ligand established that eosinophil recruitment uses a dedicated chemokine–receptor axis distinct from other CC chemokine pathways.\",\n      \"evidence\": \"Differential display cloning, recombinant protein calcium flux assay, chemotaxis, competitive radioligand binding on CCR3-transfected cells, and in vivo eosinophil accumulation in cynomolgus monkeys\",\n      \"pmids\": [\"10415065\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No crystal structure of the CCL26–CCR3 complex\", \"In vivo specificity of CCR3-dependence not confirmed by receptor knockout\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"The NMR solution structure revealed a monomeric chemokine fold with flexible N-terminal and N-loop regions implicated in CCR3 activation, providing a structural basis for receptor engagement and specificity.\",\n      \"evidence\": \"NMR spectroscopy with 15N relaxation dynamics and model-free analysis\",\n      \"pmids\": [\"11425309\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No co-structure with CCR3\", \"Functional validation of specific residues by mutagenesis not reported in this study\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Demonstration that surface-associated CCL26 on IL-4-stimulated endothelium drives shear-dependent eosinophil transmigration via CCR3/Gi signaling established a haptotactic mechanism for eosinophil recruitment across vascular barriers.\",\n      \"evidence\": \"RT-PCR, Western blot, anti-eotaxin-3 and anti-CCR3 antibody blocking, pertussis toxin, laminar flow transmigration assay on HUVECs\",\n      \"pmids\": [\"11748272\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of surface-anchoring proteins/GAGs not fully resolved\", \"In vivo relevance of surface-bound vs. soluble CCL26 not tested\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Characterization of IL-4/IL-13 as the primary inducers (with TNF-α synergy and dexamethasone suppression) in fibroblasts and epithelial cells defined the Th2 cytokine dependence of CCL26 transcription.\",\n      \"evidence\": \"Northern hybridization with dose-response and time-course cytokine stimulation in dermal fibroblasts and lung epithelial cells\",\n      \"pmids\": [\"12061839\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Signaling intermediates not mapped in this study\", \"Promoter elements not identified\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Discovery that CCL26 acts as a natural antagonist at CCR2 (and later CCR1/CCR5) while being an agonist at CCR3 revealed an unusual dual-function chemokine that simultaneously recruits eosinophils and repels monocytes.\",\n      \"evidence\": \"Chemotaxis/chemorepulsion, Ca²⁺ mobilization, ERK phosphorylation, enzyme release in monocytes and CCR2/CCR1/CCR5-transfected cells with pertussis toxin and receptor antagonists\",\n      \"pmids\": [\"12689946\", \"15039444\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis for agonist vs. antagonist behavior at different receptors not resolved at atomic level\", \"In vivo relevance of monocyte chemorepulsion not demonstrated\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Mapping CCR3-downstream signaling (ERK1/2, p38 MAPK, PI3K) for CCL26-induced eosinophil degranulation delineated the effector pathways linking receptor engagement to functional eosinophil activation.\",\n      \"evidence\": \"Eosinophil peroxidase release assay with pharmacological inhibitors in HL-60 eosinophilic cells\",\n      \"pmids\": [\"12784909\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Performed in HL-60 differentiated line, not primary eosinophils\", \"Relative contribution of each pathway not quantified\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Identification of the proximal STAT6 binding site as the key IL-4 response element in the CCL26 promoter, via JAK1/JAK2–STAT6, established the core transcriptional mechanism for Th2-induced CCL26 expression.\",\n      \"evidence\": \"Promoter deletion, site-directed mutagenesis, dominant-negative STAT constructs, JAK inhibitors in HaCaT keratinocytes; confirmed and extended in 2012 study\",\n      \"pmids\": [\"16045735\", \"22226123\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Chromatin accessibility and epigenetic regulation at this locus not characterized beyond H3K4me3 at the time\", \"Cell-type-specific enhancers not mapped\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"The finding that CCL26 autoregulates its own synthesis via CCR3 on epithelial cells revealed a negative feedback loop limiting eosinophil chemoattractant production.\",\n      \"evidence\": \"ELISA, flow cytometry for CCR3 expression, CCR3 antagonist SB-328437, neutralizing antibody in A549 cells\",\n      \"pmids\": [\"15863444\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Autocrine loop not confirmed in primary airway epithelium\", \"Downstream signaling mediating the negative feedback not identified\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Demonstration that surface-bound CCL26 on airway epithelial cells is the dominant functional pool driving eosinophil transepithelial migration extended the haptotactic mechanism from endothelium to epithelium.\",\n      \"evidence\": \"In vitro transepithelial migration assay with anti-eotaxin-3 and anti-CCR3 blocking, surface localization studies in IL-4-stimulated epithelial cells\",\n      \"pmids\": [\"16983721\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specific surface-binding proteins not identified\", \"Relative contributions of GAG-dependent vs. protein-dependent anchoring not fully resolved\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"ChIP studies showing omeprazole blocks STAT6, RNA Pol II, and H3K4me3 recruitment to the CCL26 promoter without affecting STAT6 phosphorylation or nuclear translocation revealed a chromatin-level regulatory mechanism for pharmacological suppression of CCL26.\",\n      \"evidence\": \"ChIP assay, reporter construct, Western blot for STAT6 phosphorylation/translocation in esophageal squamous cells\",\n      \"pmids\": [\"23185525\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct molecular target of omeprazole at the chromatin level not identified\", \"Whether this mechanism operates in vivo in eosinophilic esophagitis tissue not confirmed\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"CCL26 was found to signal through CX3CR1 on NK cells, expanding its receptor repertoire beyond CCR3 and its antagonist targets.\",\n      \"evidence\": \"Microchemotaxis chamber, flow cytometry for CX3CR1, confocal microscopy, genistein inhibition on human NK cells\",\n      \"pmids\": [\"23414540\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct binding affinity to CX3CR1 not measured\", \"Relative physiological importance of CX3CR1 vs. CCR3 signaling unknown\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Discovery of direct bactericidal activity concentrated in the C-terminal α-helix, with mast cell protease cleavage generating functionally distinct N-terminal (LPS-neutralizing) and C-terminal (bactericidal) fragments, established CCL26 as a bifunctional innate immune effector.\",\n      \"evidence\": \"Viable count assay, electron microscopy, membrane permeabilization, mass spectrometry of chymase/tryptase cleavage products, LPS neutralization assay\",\n      \"pmids\": [\"25377782\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo antimicrobial role not demonstrated\", \"Whether protease cleavage occurs at mucosal surfaces in allergic tissue not shown\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Identification of nongastric H⁺,K⁺-ATPase (ATP12A) as a mediator of IL-13-induced CCL26 expression linked ion transport and intracellular pH to Th2 chemokine regulation.\",\n      \"evidence\": \"siRNA knockdown of ATP12A, intracellular pH imaging, proton pump inhibitor treatment in sinonasal epithelial cells\",\n      \"pmids\": [\"27717558\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How intracellular pH changes feed into STAT6 or ERK signaling not resolved\", \"Generalizability beyond sinonasal epithelium not established at that time\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"CISH, induced by IL-13 via STAT6, was identified as a negative-feedback regulator of CCL26 production, connecting SOCS-family signaling to eosinophil chemoattractant control.\",\n      \"evidence\": \"siRNA knockdown and overexpression of CISH, cDNA microarray, ELISA, Western blot in human lung fibroblasts\",\n      \"pmids\": [\"30197185\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct mechanism by which CISH suppresses CCL26 transcription not defined\", \"Not confirmed in epithelial cells or in vivo\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"15-lipoxygenase 1 was shown to promote CCL26 expression via ERK activation, integrating lipid mediator signaling into the transcriptional regulation of this chemokine.\",\n      \"evidence\": \"DsiRNA knockdown, pharmacological 15LO1 inhibition, ERK inhibitors, ELISA, Western blot in nasal epithelial cells\",\n      \"pmids\": [\"31301373\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specific 15LO1 metabolite mediating ERK activation not identified\", \"Interaction with STAT6 pathway not fully delineated\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"IL-4-induced CCL26 secretion was shown to require ER calcium release and L-type calcium channel entry, with pharmacological blockade (verapamil, diltiazem) suppressing CCL26, connecting the ngH⁺,K⁺-ATPase pathway to a defined calcium signaling mechanism.\",\n      \"evidence\": \"Fluo-4 calcium imaging, pharmacological inhibitors (omeprazole, verapamil, diltiazem, 2-APB, EGTA-AM), ELISA, RNA-seq of patient biopsies in esophageal squamous cells\",\n      \"pmids\": [\"33581123\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How calcium flux regulates STAT6 promoter occupancy or mRNA stability not defined\", \"Whether calcium channel blockers have therapeutic efficacy in eosinophilic esophagitis not proven\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Conditional CCL26 knockout in airway epithelial cells demonstrated that CCL26 activates CX3CR1⁺ alveolar macrophages to secrete C1q, driving eosinophil clearance and resolution of allergic lung inflammation — establishing CCL26 as a pro-resolution mediator, not just a pro-inflammatory chemokine.\",\n      \"evidence\": \"Conditional CCL26 knockout mice, CX3CR1 macrophage depletion, mass cytometry, single-cell RNA-seq, human allergen bronchoprovocation\",\n      \"pmids\": [\"36790376\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular mechanism of CX3CR1 signaling leading to C1q secretion not defined\", \"Whether this resolution pathway operates in non-pulmonary tissues unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the atomic-resolution structure of CCL26 bound to CCR3 vs. CX3CR1, the structural determinants that switch CCL26 from agonist (CCR3) to antagonist (CCR1/CCR2/CCR5), the in vivo antimicrobial significance of the C-terminal bactericidal domain, and how the calcium/pH and 15LO1–ERK pathways converge with STAT6 at the chromatin level to regulate CCL26 transcription.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No co-crystal or cryo-EM structure of CCL26 with any receptor\", \"In vivo antimicrobial function not tested\", \"Integrated signaling model connecting STAT6, ERK, calcium, and 15LO1 pathways at the promoter not available\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0048018\", \"supporting_discovery_ids\": [0, 3, 4, 28]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [3, 4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [0, 2, 8]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [2, 8]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [0, 2, 8, 20, 25]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 3, 4, 19, 27, 28]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"CCR3\", \"CCR2\", \"CCR1\", \"CCR5\", \"CX3CR1\", \"STAT6\"],\n    \"other_free_text\": []\n  }\n}\n```"}