{"gene":"LXN","run_date":"2026-06-10T02:59:50","timeline":{"discoveries":[{"year":2013,"finding":"LXN localizes to the nucleus of prostate epithelial cells (distinct from RARRES1 which resides in the endoplasmic reticulum), and siRNA suppression of LXN increases colony-forming ability and invasive capacity of primary prostate cultures; atRA-induced LXN expression suppresses invasion and stem cell properties.","method":"siRNA knockdown, cell imaging/subcellular fractionation, colony-forming assay, invasion assay, DNA methylation inhibition","journal":"Oncogenesis","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function with specific phenotypic readouts (invasion, colony formation) and direct localization experiment; single lab, multiple orthogonal methods","pmids":["23588494"],"is_preprint":false},{"year":2021,"finding":"LXN interacts with Filamin A (FLNA) and regulates FLNA proteolytic cleavage and nuclear translocation; LXN knockdown induces F-actin remodeling and morphological changes in endothelial cells similar to laminar shear stress effects; LXN deficiency improves vascular permeability, vasodilation, and reduces atherosclerosis in mice.","method":"siRNA knockdown, Co-IP/pulldown (LXN–FLNA interaction), cell imaging, LXN-/- and ApoE-/-LXN-/- double-knockout mouse models","journal":"Journal of cellular and molecular medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal interaction assay plus KO mouse phenotype plus imaging; single lab, multiple orthogonal methods","pmids":["34085389"],"is_preprint":false},{"year":2022,"finding":"LXN inhibits STAT3 transcriptional activity by targeting JAK1 in macrophages; LXN deficiency enhances PD-L2 (not PD-L1) expression in macrophages, which suppresses T cell function in the tumor microenvironment; adoptive transfer of wild-type macrophages rescues T cell function in LXN-deficient mice.","method":"LXN-deficient mouse models, adoptive macrophage transfer, JAK1/STAT3 signaling assays, flow cytometry, subcutaneous tumor and AOM/DSS colorectal cancer models, PD-L2 blockade","journal":"Cell death discovery","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic KO with defined cellular phenotype plus adoptive transfer rescue plus mechanistic pathway assay; single lab","pmids":["36323670"],"is_preprint":false},{"year":2024,"finding":"LXN deficiency in intestinal stem cells activates YAP and Wnt signaling pathways, upregulates Lgr5 expression, and promotes ISC proliferation and intestinal organoid development; LXN co-localizes with Lgr5 in intestinal crypts.","method":"LXN-/- mice, intestinal organoid culture, siRNA knockdown, co-localization imaging, western blot for YAP/Wnt pathway components","journal":"International journal of biological macromolecules","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KO mouse with organoid phenotype plus pathway analysis; single lab, multiple methods","pmids":["39208900"],"is_preprint":false},{"year":2024,"finding":"LXN secreted by macrophages into exosomes inhibits CD4+ T cell differentiation into regulatory T (Treg) cells in vitro and in vivo, enhancing tumor immune surveillance.","method":"Macrophage-T cell co-culture system, exosome isolation and characterization, flow cytometry, in vivo mouse tumor models with LXN-loaded biomimetic nanoparticles","journal":"International journal of biological macromolecules","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-culture functional assay with exosome characterization and in vivo confirmation; single lab","pmids":["39694381"],"is_preprint":false},{"year":2025,"finding":"LXN activates an LXN/Rps3/p53 signaling pathway in renal tubular epithelial cells (RTECs) under oxalate-induced oxidative stress, promoting premature RTEC senescence and SASP factor secretion, which drives M1-like macrophage polarization and increases calcium oxalate crystal deposition; siRNA knockdown of LXN and AAV-mediated LXN silencing in vivo reduced RTEC senescence, M1 macrophage polarization, and intrarenal crystal deposition.","method":"siRNA knockdown, AAV-mediated gene silencing in rat model, SA-β-gal staining, western blot, immunohistochemistry, SASP cytokine measurement, macrophage co-culture","journal":"Frontiers in immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function in vitro and in vivo with defined pathway components and phenotypic readouts; single lab","pmids":["41112268"],"is_preprint":false},{"year":2026,"finding":"LXN knockdown in hepatic stellate cells (LX-2 line) reduces CCl4-induced liver injury, suppresses HSC activation, and inhibits α-SMA and collagen I expression; LXN positively correlates with THBS2 and LXN knockdown downregulates THBS2, defining an LXN-THBS2 signaling axis in liver fibrosis.","method":"AAV9-mediated LXN knockdown in mouse liver fibrosis model, siRNA knockdown in LX-2 cells, qPCR, western blot, immunohistochemistry, immunofluorescence","journal":"Frontiers in bioscience (Landmark edition)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function in vitro and in vivo with specific molecular and phenotypic readouts; single lab, multiple methods","pmids":["41761978"],"is_preprint":false},{"year":2024,"finding":"In smooth muscle cells (SMCs), LXN deficiency attenuates SMC proliferation and migration by inhibiting platelet-derived growth factor (PDGF) receptor expression; in macrophages, LXN deficiency inhibits MCP-1-induced macrophage migration by suppressing ERK phosphorylation; SMC-specific and myeloid-specific (but not endothelial-specific) LXN knockout markedly prevents neointimal hyperplasia after carotid artery ligation.","method":"Cell-type-specific LXN knockout mice (global, SMC-specific, endothelial-specific, myeloid-specific), carotid artery ligation model, western blot, immunofluorescence, proliferation/migration assays","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple cell-type-specific KO mice with defined mechanistic readouts (PDGF-R, ERK); single lab, preprint","pmids":[],"is_preprint":true},{"year":2024,"finding":"LXN knockdown reduces the migratory capacity of endometrial stromal cells while promoting cell viability, implicating LXN in regulating proliferation and migration of endometriotic stromal cells.","method":"siRNA knockdown, Transwell migration assay, MTT cell viability assay","journal":"Genes","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, single KD approach with phenotypic readout but no pathway placement","pmids":["39202445"],"is_preprint":false}],"current_model":"LXN (Latexin) is a zinc-dependent metallocarboxypeptidase inhibitor that functions as a context-dependent regulator of stem cell proliferation, immune polarization, and vascular biology: it localizes to the nucleus in epithelial cells where it suppresses invasion and colony formation; in macrophages it inhibits the JAK1/STAT3 axis to restrain M2 polarization and PD-L2 expression, and is secreted via exosomes to suppress Treg differentiation; in endothelial cells it interacts with Filamin A to regulate cytoskeletal remodeling; in SMCs it supports PDGF receptor expression and proliferation/migration; and in intestinal stem cells its loss activates YAP and Wnt pathways to enhance Lgr5+ ISC proliferation, while in RTECs it drives Rps3/p53-dependent senescence promoting M1 macrophage polarization."},"narrative":{"mechanistic_narrative":"LXN (Latexin) is a context-dependent intracellular and secreted regulator of cell proliferation, migration, and immune polarization that acts through distinct partner proteins and signaling axes in different cell types [PMID:23588494, PMID:36323670]. In prostate epithelial cells LXN localizes to the nucleus and restrains colony formation and invasion, with its expression inducible by all-trans retinoic acid [PMID:23588494]. Mechanistically, LXN engages discrete effectors depending on cellular context: it binds Filamin A and controls FLNA proteolytic cleavage and nuclear translocation to govern F-actin remodeling in endothelial cells [PMID:34085389]; in smooth muscle cells it supports PDGF receptor expression to drive proliferation and migration, while in macrophages it promotes MCP-1-induced migration via ERK phosphorylation, and cell-type-specific deletion in SMCs and myeloid cells prevents neointimal hyperplasia. In macrophages LXN inhibits the JAK1/STAT3 axis to limit PD-L2 expression and is secreted in exosomes to suppress Treg differentiation, together restraining immunosuppression in the tumor microenvironment [PMID:36323670, PMID:39694381]. In epithelial stem-cell and stress settings LXN is anti-proliferative or pro-senescent: its loss in intestinal stem cells activates YAP and Wnt signaling to expand Lgr5+ ISCs [PMID:39208900], whereas under oxalate stress in renal tubular epithelial cells it activates an Rps3/p53 pathway driving senescence, SASP secretion, and M1 macrophage polarization [PMID:41112268]. LXN also operates in fibrogenesis through an LXN-THBS2 axis promoting hepatic stellate cell activation [PMID:41761978].","teleology":[{"year":2013,"claim":"Established LXN as a nuclear tumor-suppressor-like protein in epithelial cells, distinguishing its subcellular behavior and function from related factors and linking it to invasion and stem-cell properties.","evidence":"siRNA knockdown, subcellular fractionation/imaging, colony-forming and invasion assays in primary prostate cultures with atRA induction","pmids":["23588494"],"confidence":"Medium","gaps":["No molecular partner or downstream effector identified for the nuclear suppressive activity","Mechanism of nuclear localization unresolved"]},{"year":2021,"claim":"Identified a direct physical partner (Filamin A) and a cytoskeletal mechanism, explaining how LXN influences endothelial morphology and vascular biology.","evidence":"Co-IP/pulldown for LXN-FLNA interaction, F-actin imaging, and LXN-/- / ApoE-/-LXN-/- mouse vascular phenotyping","pmids":["34085389"],"confidence":"Medium","gaps":["Whether LXN directly modulates the protease cleaving FLNA is unresolved","Reciprocal validation of interaction within the timeline limited to one study"]},{"year":2022,"claim":"Placed LXN in a defined immune signaling pathway by showing it inhibits JAK1/STAT3 to limit PD-L2 and macrophage-driven T cell suppression in the tumor microenvironment.","evidence":"LXN-deficient mice, adoptive macrophage transfer rescue, JAK1/STAT3 assays, flow cytometry, tumor and AOM/DSS models with PD-L2 blockade","pmids":["36323670"],"confidence":"Medium","gaps":["Direct biochemical engagement of JAK1 by LXN not structurally defined","Selectivity for PD-L2 over PD-L1 mechanistically unexplained"]},{"year":2024,"claim":"Extended LXN's immune role to a secreted, exosome-delivered function that suppresses Treg differentiation, indicating both intracellular and extracellular modes of action.","evidence":"Macrophage-T cell co-culture, exosome isolation/characterization, flow cytometry, in vivo tumor models with LXN-loaded nanoparticles","pmids":["39694381"],"confidence":"Medium","gaps":["Molecular target of secreted LXN on CD4+ T cells not identified","Mechanism of exosomal sorting of LXN unknown"]},{"year":2024,"claim":"Revealed an anti-proliferative role in intestinal stem cells, linking LXN loss to YAP/Wnt activation and Lgr5+ ISC expansion.","evidence":"LXN-/- mice, intestinal organoids, siRNA, co-localization imaging, western blot for YAP/Wnt components","pmids":["39208900"],"confidence":"Medium","gaps":["Direct molecular link between LXN and YAP/Wnt machinery not defined","Whether effect is cell-autonomous to ISCs unclear"]},{"year":2024,"claim":"Defined cell-type-specific contributions to vascular remodeling, showing SMC and myeloid (not endothelial) LXN drives neointimal hyperplasia via PDGF-R and ERK signaling.","evidence":"Global and cell-type-specific LXN knockout mice, carotid artery ligation, proliferation/migration assays (preprint)","pmids":[],"confidence":"Medium","gaps":["Preprint; not yet peer-reviewed","Mechanism by which LXN supports PDGF-R expression not defined"]},{"year":2024,"claim":"Implicated LXN in proliferation/migration control of endometrial stromal cells, broadening its tissue contexts.","evidence":"siRNA knockdown, Transwell migration, MTT viability in endometrial stromal cells","pmids":["39202445"],"confidence":"Low","gaps":["No pathway placement or molecular mechanism","Single knockdown approach without orthogonal validation"]},{"year":2025,"claim":"Identified an LXN/Rps3/p53 senescence pathway linking oxidative stress in renal epithelium to inflammatory macrophage polarization and crystal deposition.","evidence":"siRNA and AAV-mediated silencing in rat, SA-β-gal staining, SASP measurement, macrophage co-culture","pmids":["41112268"],"confidence":"Medium","gaps":["Direct biochemical interaction of LXN with Rps3/p53 not shown","Generality beyond oxalate-induced stress untested"]},{"year":2026,"claim":"Defined an LXN-THBS2 axis in hepatic stellate cell activation and liver fibrosis, adding a fibrogenic role.","evidence":"AAV9-mediated LXN knockdown in mouse fibrosis model, siRNA in LX-2 cells, qPCR/western/IHC","pmids":["41761978"],"confidence":"Medium","gaps":["Whether LXN regulates THBS2 directly or indirectly unresolved","No physical interaction demonstrated"]},{"year":null,"claim":"How a single protein executes opposite (suppressive vs. pro-proliferative/pro-senescent) functions across cell types, and whether its reported carboxypeptidase-inhibitory activity underlies any of these signaling roles, remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unifying biochemical mechanism reconciling context-specific roles","Enzymatic/inhibitory activity not connected to documented signaling phenotypes in the corpus"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[2,7]},{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[1]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0]},{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[4]}],"pathway":[{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[2,4]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[3,7]},{"term_id":"R-HSA-8953897","term_label":"Cellular responses to stimuli","supporting_discovery_ids":[5]}],"complexes":[],"partners":["FLNA","JAK1","STAT3"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9BS40","full_name":"Latexin","aliases":["Endogenous carboxypeptidase inhibitor","ECI","Protein MUM","Tissue carboxypeptidase inhibitor","TCI"],"length_aa":222,"mass_kda":25.8,"function":"Hardly reversible, non-competitive, and potent inhibitor of CPA1, CPA2 and CPA4. May play a role in inflammation","subcellular_location":"Cytoplasm","url":"https://www.uniprot.org/uniprotkb/Q9BS40/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/LXN","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/LXN","total_profiled":1310},"omim":[{"mim_id":"609305","title":"LATEXIN; LXN","url":"https://www.omim.org/entry/609305"},{"mim_id":"607635","title":"CARBOXYPEPTIDASE A4; CPA4","url":"https://www.omim.org/entry/607635"},{"mim_id":"601573","title":"ENHANCER OF ZESTE 2 POLYCOMB REPRESSIVE COMPLEX 2 SUBUNIT; EZH2","url":"https://www.omim.org/entry/601573"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"},{"location":"Cytosol","reliability":"Approved"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/LXN"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"Q9BS40","domains":[{"cath_id":"3.10.450.10","chopping":"9-93","consensus_level":"medium","plddt":97.0999,"start":9,"end":93},{"cath_id":"3.10.450.10","chopping":"101-215","consensus_level":"medium","plddt":97.5702,"start":101,"end":215}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9BS40","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9BS40-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9BS40-F1-predicted_aligned_error_v6.png","plddt_mean":95.94},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=LXN","jax_strain_url":"https://www.jax.org/strain/search?query=LXN"},"sequence":{"accession":"Q9BS40","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9BS40.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9BS40/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9BS40"}},"corpus_meta":[{"pmid":"23588494","id":"PMC_23588494","title":"Retinoic acid represses invasion and stem cell phenotype by induction of the metastasis suppressors RARRES1 and LXN.","date":"2013","source":"Oncogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/23588494","citation_count":50,"is_preprint":false},{"pmid":"36323670","id":"PMC_36323670","title":"Loss of LXN promotes macrophage M2 polarization and PD-L2 expression contributing cancer immune-escape in mice.","date":"2022","source":"Cell death discovery","url":"https://pubmed.ncbi.nlm.nih.gov/36323670","citation_count":11,"is_preprint":false},{"pmid":"34085389","id":"PMC_34085389","title":"LXN deficiency regulates cytoskeleton remodelling by promoting proteolytic cleavage of Filamin A in vascular endothelial cells.","date":"2021","source":"Journal of cellular and molecular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/34085389","citation_count":9,"is_preprint":false},{"pmid":"38442573","id":"PMC_38442573","title":"Therapeutic potential of ADSC-EV-derived lncRNA DLEU2: A novel molecular pathway in alleviating sepsis-induced lung injury via the miR-106a-5p/LXN axis.","date":"2024","source":"International immunopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/38442573","citation_count":7,"is_preprint":false},{"pmid":"36949500","id":"PMC_36949500","title":"Circ_0002715 promotes the development of osteoarthritis through regulating LXN by sponging miR-127-5p.","date":"2023","source":"Journal of orthopaedic surgery and research","url":"https://pubmed.ncbi.nlm.nih.gov/36949500","citation_count":6,"is_preprint":false},{"pmid":"41112268","id":"PMC_41112268","title":"Premature renal epithelial cell senescence promoted by LXN/Rps3/p53 signaling pathway activation increases calcium oxalate crystal deposition by altering macrophage polarization.","date":"2025","source":"Frontiers in immunology","url":"https://pubmed.ncbi.nlm.nih.gov/41112268","citation_count":2,"is_preprint":false},{"pmid":"39208900","id":"PMC_39208900","title":"Carboxypeptidase inhibitor Latexin (LXN) regulates intestinal organogenesis and intestinal remodeling involved in intestinal injury repair in mice.","date":"2024","source":"International journal of biological macromolecules","url":"https://pubmed.ncbi.nlm.nih.gov/39208900","citation_count":2,"is_preprint":false},{"pmid":"39202445","id":"PMC_39202445","title":"Carboxypeptidase Inhibitor LXN Expression in Endometrial Tissue Is Menstrual Cycle Phase-Dependent and Is Upregulated in Endometriotic Lesions.","date":"2024","source":"Genes","url":"https://pubmed.ncbi.nlm.nih.gov/39202445","citation_count":2,"is_preprint":false},{"pmid":"39694381","id":"PMC_39694381","title":"Latexin (LXN) enhances tumor immune surveillance in mice by inhibiting Treg cells through the macrophage exosome pathway.","date":"2024","source":"International journal of biological macromolecules","url":"https://pubmed.ncbi.nlm.nih.gov/39694381","citation_count":1,"is_preprint":false},{"pmid":"41761978","id":"PMC_41761978","title":"LXN-THBS2 Signaling Axis Regulates Hepatic Stellate Cell Activation and Promotes the Development of Liver Fibrosis.","date":"2026","source":"Frontiers in bioscience (Landmark edition)","url":"https://pubmed.ncbi.nlm.nih.gov/41761978","citation_count":0,"is_preprint":false},{"pmid":"42164484","id":"PMC_42164484","title":"Correction: Premature renal epithelial cell senescence promoted by LXN/Rps3/p53 signaling pathway activation increases calcium oxalate crystal deposition by altering macrophage polarization.","date":"2026","source":"Frontiers in immunology","url":"https://pubmed.ncbi.nlm.nih.gov/42164484","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2024.10.03.616555","title":"Latexin facilitates neointimal formation via promoting smooth muscle cell proliferation and macrophage migration","date":"2024-10-04","source":"bioRxiv","url":"https://doi.org/10.1101/2024.10.03.616555","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.09.06.24312838","title":"Divergent inflammatory and neurology-related plasma protein profiles in individuals with long COVID following primary and breakthrough SARS-CoV-2 infections","date":"2024-09-06","source":"bioRxiv","url":"https://doi.org/10.1101/2024.09.06.24312838","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.08.02.24310874","title":"Genetics of Cardiac Aging Implicate Organ-Specific Variation","date":"2024-08-06","source":"bioRxiv","url":"https://doi.org/10.1101/2024.08.02.24310874","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":10212,"output_tokens":2389,"usd":0.033236,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9499,"output_tokens":3136,"usd":0.062948,"stage2_stop_reason":"end_turn"},"total_usd":0.096184,"stage1_batch_id":"msgbatch_01BbTCMyrRPyhtEq6b1MdwCN","stage2_batch_id":"msgbatch_011dEed5bbxYvTAaQWKJevxu","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2013,\n      \"finding\": \"LXN localizes to the nucleus of prostate epithelial cells (distinct from RARRES1 which resides in the endoplasmic reticulum), and siRNA suppression of LXN increases colony-forming ability and invasive capacity of primary prostate cultures; atRA-induced LXN expression suppresses invasion and stem cell properties.\",\n      \"method\": \"siRNA knockdown, cell imaging/subcellular fractionation, colony-forming assay, invasion assay, DNA methylation inhibition\",\n      \"journal\": \"Oncogenesis\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function with specific phenotypic readouts (invasion, colony formation) and direct localization experiment; single lab, multiple orthogonal methods\",\n      \"pmids\": [\"23588494\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"LXN interacts with Filamin A (FLNA) and regulates FLNA proteolytic cleavage and nuclear translocation; LXN knockdown induces F-actin remodeling and morphological changes in endothelial cells similar to laminar shear stress effects; LXN deficiency improves vascular permeability, vasodilation, and reduces atherosclerosis in mice.\",\n      \"method\": \"siRNA knockdown, Co-IP/pulldown (LXN–FLNA interaction), cell imaging, LXN-/- and ApoE-/-LXN-/- double-knockout mouse models\",\n      \"journal\": \"Journal of cellular and molecular medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal interaction assay plus KO mouse phenotype plus imaging; single lab, multiple orthogonal methods\",\n      \"pmids\": [\"34085389\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"LXN inhibits STAT3 transcriptional activity by targeting JAK1 in macrophages; LXN deficiency enhances PD-L2 (not PD-L1) expression in macrophages, which suppresses T cell function in the tumor microenvironment; adoptive transfer of wild-type macrophages rescues T cell function in LXN-deficient mice.\",\n      \"method\": \"LXN-deficient mouse models, adoptive macrophage transfer, JAK1/STAT3 signaling assays, flow cytometry, subcutaneous tumor and AOM/DSS colorectal cancer models, PD-L2 blockade\",\n      \"journal\": \"Cell death discovery\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KO with defined cellular phenotype plus adoptive transfer rescue plus mechanistic pathway assay; single lab\",\n      \"pmids\": [\"36323670\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"LXN deficiency in intestinal stem cells activates YAP and Wnt signaling pathways, upregulates Lgr5 expression, and promotes ISC proliferation and intestinal organoid development; LXN co-localizes with Lgr5 in intestinal crypts.\",\n      \"method\": \"LXN-/- mice, intestinal organoid culture, siRNA knockdown, co-localization imaging, western blot for YAP/Wnt pathway components\",\n      \"journal\": \"International journal of biological macromolecules\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KO mouse with organoid phenotype plus pathway analysis; single lab, multiple methods\",\n      \"pmids\": [\"39208900\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"LXN secreted by macrophages into exosomes inhibits CD4+ T cell differentiation into regulatory T (Treg) cells in vitro and in vivo, enhancing tumor immune surveillance.\",\n      \"method\": \"Macrophage-T cell co-culture system, exosome isolation and characterization, flow cytometry, in vivo mouse tumor models with LXN-loaded biomimetic nanoparticles\",\n      \"journal\": \"International journal of biological macromolecules\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-culture functional assay with exosome characterization and in vivo confirmation; single lab\",\n      \"pmids\": [\"39694381\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"LXN activates an LXN/Rps3/p53 signaling pathway in renal tubular epithelial cells (RTECs) under oxalate-induced oxidative stress, promoting premature RTEC senescence and SASP factor secretion, which drives M1-like macrophage polarization and increases calcium oxalate crystal deposition; siRNA knockdown of LXN and AAV-mediated LXN silencing in vivo reduced RTEC senescence, M1 macrophage polarization, and intrarenal crystal deposition.\",\n      \"method\": \"siRNA knockdown, AAV-mediated gene silencing in rat model, SA-β-gal staining, western blot, immunohistochemistry, SASP cytokine measurement, macrophage co-culture\",\n      \"journal\": \"Frontiers in immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function in vitro and in vivo with defined pathway components and phenotypic readouts; single lab\",\n      \"pmids\": [\"41112268\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"LXN knockdown in hepatic stellate cells (LX-2 line) reduces CCl4-induced liver injury, suppresses HSC activation, and inhibits α-SMA and collagen I expression; LXN positively correlates with THBS2 and LXN knockdown downregulates THBS2, defining an LXN-THBS2 signaling axis in liver fibrosis.\",\n      \"method\": \"AAV9-mediated LXN knockdown in mouse liver fibrosis model, siRNA knockdown in LX-2 cells, qPCR, western blot, immunohistochemistry, immunofluorescence\",\n      \"journal\": \"Frontiers in bioscience (Landmark edition)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function in vitro and in vivo with specific molecular and phenotypic readouts; single lab, multiple methods\",\n      \"pmids\": [\"41761978\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"In smooth muscle cells (SMCs), LXN deficiency attenuates SMC proliferation and migration by inhibiting platelet-derived growth factor (PDGF) receptor expression; in macrophages, LXN deficiency inhibits MCP-1-induced macrophage migration by suppressing ERK phosphorylation; SMC-specific and myeloid-specific (but not endothelial-specific) LXN knockout markedly prevents neointimal hyperplasia after carotid artery ligation.\",\n      \"method\": \"Cell-type-specific LXN knockout mice (global, SMC-specific, endothelial-specific, myeloid-specific), carotid artery ligation model, western blot, immunofluorescence, proliferation/migration assays\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple cell-type-specific KO mice with defined mechanistic readouts (PDGF-R, ERK); single lab, preprint\",\n      \"pmids\": [],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"LXN knockdown reduces the migratory capacity of endometrial stromal cells while promoting cell viability, implicating LXN in regulating proliferation and migration of endometriotic stromal cells.\",\n      \"method\": \"siRNA knockdown, Transwell migration assay, MTT cell viability assay\",\n      \"journal\": \"Genes\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, single KD approach with phenotypic readout but no pathway placement\",\n      \"pmids\": [\"39202445\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"LXN (Latexin) is a zinc-dependent metallocarboxypeptidase inhibitor that functions as a context-dependent regulator of stem cell proliferation, immune polarization, and vascular biology: it localizes to the nucleus in epithelial cells where it suppresses invasion and colony formation; in macrophages it inhibits the JAK1/STAT3 axis to restrain M2 polarization and PD-L2 expression, and is secreted via exosomes to suppress Treg differentiation; in endothelial cells it interacts with Filamin A to regulate cytoskeletal remodeling; in SMCs it supports PDGF receptor expression and proliferation/migration; and in intestinal stem cells its loss activates YAP and Wnt pathways to enhance Lgr5+ ISC proliferation, while in RTECs it drives Rps3/p53-dependent senescence promoting M1 macrophage polarization.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"LXN (Latexin) is a context-dependent intracellular and secreted regulator of cell proliferation, migration, and immune polarization that acts through distinct partner proteins and signaling axes in different cell types [#0, #2, #7]. In prostate epithelial cells LXN localizes to the nucleus and restrains colony formation and invasion, with its expression inducible by all-trans retinoic acid [#0]. Mechanistically, LXN engages discrete effectors depending on cellular context: it binds Filamin A and controls FLNA proteolytic cleavage and nuclear translocation to govern F-actin remodeling in endothelial cells [#1]; in smooth muscle cells it supports PDGF receptor expression to drive proliferation and migration, while in macrophages it promotes MCP-1-induced migration via ERK phosphorylation, and cell-type-specific deletion in SMCs and myeloid cells prevents neointimal hyperplasia [#7]. In macrophages LXN inhibits the JAK1/STAT3 axis to limit PD-L2 expression and is secreted in exosomes to suppress Treg differentiation, together restraining immunosuppression in the tumor microenvironment [#2, #4]. In epithelial stem-cell and stress settings LXN is anti-proliferative or pro-senescent: its loss in intestinal stem cells activates YAP and Wnt signaling to expand Lgr5+ ISCs [#3], whereas under oxalate stress in renal tubular epithelial cells it activates an Rps3/p53 pathway driving senescence, SASP secretion, and M1 macrophage polarization [#5]. LXN also operates in fibrogenesis through an LXN-THBS2 axis promoting hepatic stellate cell activation [#6].\",\n  \"teleology\": [\n    {\n      \"year\": 2013,\n      \"claim\": \"Established LXN as a nuclear tumor-suppressor-like protein in epithelial cells, distinguishing its subcellular behavior and function from related factors and linking it to invasion and stem-cell properties.\",\n      \"evidence\": \"siRNA knockdown, subcellular fractionation/imaging, colony-forming and invasion assays in primary prostate cultures with atRA induction\",\n      \"pmids\": [\"23588494\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No molecular partner or downstream effector identified for the nuclear suppressive activity\", \"Mechanism of nuclear localization unresolved\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Identified a direct physical partner (Filamin A) and a cytoskeletal mechanism, explaining how LXN influences endothelial morphology and vascular biology.\",\n      \"evidence\": \"Co-IP/pulldown for LXN-FLNA interaction, F-actin imaging, and LXN-/- / ApoE-/-LXN-/- mouse vascular phenotyping\",\n      \"pmids\": [\"34085389\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether LXN directly modulates the protease cleaving FLNA is unresolved\", \"Reciprocal validation of interaction within the timeline limited to one study\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Placed LXN in a defined immune signaling pathway by showing it inhibits JAK1/STAT3 to limit PD-L2 and macrophage-driven T cell suppression in the tumor microenvironment.\",\n      \"evidence\": \"LXN-deficient mice, adoptive macrophage transfer rescue, JAK1/STAT3 assays, flow cytometry, tumor and AOM/DSS models with PD-L2 blockade\",\n      \"pmids\": [\"36323670\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct biochemical engagement of JAK1 by LXN not structurally defined\", \"Selectivity for PD-L2 over PD-L1 mechanistically unexplained\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Extended LXN's immune role to a secreted, exosome-delivered function that suppresses Treg differentiation, indicating both intracellular and extracellular modes of action.\",\n      \"evidence\": \"Macrophage-T cell co-culture, exosome isolation/characterization, flow cytometry, in vivo tumor models with LXN-loaded nanoparticles\",\n      \"pmids\": [\"39694381\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular target of secreted LXN on CD4+ T cells not identified\", \"Mechanism of exosomal sorting of LXN unknown\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Revealed an anti-proliferative role in intestinal stem cells, linking LXN loss to YAP/Wnt activation and Lgr5+ ISC expansion.\",\n      \"evidence\": \"LXN-/- mice, intestinal organoids, siRNA, co-localization imaging, western blot for YAP/Wnt components\",\n      \"pmids\": [\"39208900\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct molecular link between LXN and YAP/Wnt machinery not defined\", \"Whether effect is cell-autonomous to ISCs unclear\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Defined cell-type-specific contributions to vascular remodeling, showing SMC and myeloid (not endothelial) LXN drives neointimal hyperplasia via PDGF-R and ERK signaling.\",\n      \"evidence\": \"Global and cell-type-specific LXN knockout mice, carotid artery ligation, proliferation/migration assays (preprint)\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint; not yet peer-reviewed\", \"Mechanism by which LXN supports PDGF-R expression not defined\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Implicated LXN in proliferation/migration control of endometrial stromal cells, broadening its tissue contexts.\",\n      \"evidence\": \"siRNA knockdown, Transwell migration, MTT viability in endometrial stromal cells\",\n      \"pmids\": [\"39202445\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No pathway placement or molecular mechanism\", \"Single knockdown approach without orthogonal validation\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identified an LXN/Rps3/p53 senescence pathway linking oxidative stress in renal epithelium to inflammatory macrophage polarization and crystal deposition.\",\n      \"evidence\": \"siRNA and AAV-mediated silencing in rat, SA-β-gal staining, SASP measurement, macrophage co-culture\",\n      \"pmids\": [\"41112268\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct biochemical interaction of LXN with Rps3/p53 not shown\", \"Generality beyond oxalate-induced stress untested\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Defined an LXN-THBS2 axis in hepatic stellate cell activation and liver fibrosis, adding a fibrogenic role.\",\n      \"evidence\": \"AAV9-mediated LXN knockdown in mouse fibrosis model, siRNA in LX-2 cells, qPCR/western/IHC\",\n      \"pmids\": [\"41761978\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether LXN regulates THBS2 directly or indirectly unresolved\", \"No physical interaction demonstrated\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How a single protein executes opposite (suppressive vs. pro-proliferative/pro-senescent) functions across cell types, and whether its reported carboxypeptidase-inhibitory activity underlies any of these signaling roles, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unifying biochemical mechanism reconciling context-specific roles\", \"Enzymatic/inhibitory activity not connected to documented signaling phenotypes in the corpus\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [2, 7]},\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [2, 4]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [3, 7]},\n      {\"term_id\": \"R-HSA-8953897\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"FLNA\", \"JAK1\", \"STAT3\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":6,"faith_pct":83.33333333333333}}