{"gene":"BGN","run_date":"2026-06-09T22:02:44","timeline":{"discoveries":[{"year":1990,"finding":"BGN (biglycan) gene was localized to human chromosome Xq13-qter by Southern analysis of human-rodent somatic cell hybrid DNAs; the gene is approximately 6 kb in length and present as a single copy.","method":"Southern blot analysis of somatic cell hybrid DNAs","journal":"Genomics","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct chromosomal mapping with somatic cell hybrids, independently supported by fine-mapping study (PMID:1612609)","pmids":["1968422"],"is_preprint":false},{"year":1992,"finding":"BGN was fine-mapped within Xq28, proximal to red/green cone pigment genes and G6PD, and distal to DXS304/DXS305/GABRA3, identifying it as a candidate gene for X-linked dominant chondrodysplasia punctata.","method":"Somatic hybrid cell line panel with defined X chromosome breakpoints","journal":"Genomics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct cytogenetic mapping with breakpoint-defined hybrids, single lab","pmids":["1612609"],"is_preprint":false},{"year":1995,"finding":"BGN is subject to X inactivation (demonstrated via hybrid cell lines) but displays pseudo-autosomal expression behavior, likely regulated by a trans-acting gene that escapes X inactivation rather than by escape of BGN itself or a Y-chromosomal homolog.","method":"Hybrid cell line analysis, mRNA and protein expression profiling in patients with varying sex chromosome numbers","journal":"Human genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct cell-line experiments for X inactivation status plus patient expression data, single lab","pmids":["7607653"],"is_preprint":false},{"year":2015,"finding":"BGN protein directly interacts with NOTCH3 ectodomain protein in cell culture and in direct protein interaction assays; BGN accumulates in CADASIL arteries and cerebrovascular smooth muscle cells upregulate BGN in response to NOTCH3 ectodomain via an mTOR-sensitive mechanism.","method":"Direct protein interaction assay, cell culture co-incubation with purified NOTCH3 ectodomain, rapamycin (mTOR inhibitor) treatment, immunoblotting, in situ hybridization","journal":"Translational stroke research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct protein binding assay plus functional mTOR inhibition, single lab, two orthogonal methods","pmids":["25578324"],"is_preprint":false},{"year":2016,"finding":"Missense mutations in BGN (p.Lys147Glu and p.Gly259Val) cause X-linked recessive spondyloepimetaphyseal dysplasia; 3D structural simulation placed both mutated residues in the concave arc of leucine-rich repeat domains that interact with TGF-β, implicating disrupted TGF-β binding as the pathogenic mechanism.","method":"Exome sequencing, 3D structural simulation of BGN–TGF-β interaction","journal":"American journal of human genetics","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — genetic evidence replicated across three families from different ethnicities plus structural modeling; no in vitro binding assay to directly confirm TGF-β interaction disruption","pmids":["27236923"],"is_preprint":false},{"year":2019,"finding":"BGN is a direct transcriptional target of miR-185; depletion of miR-185 increases BGN expression and promotes osteogenesis through the BMP/Smad pathway, as identified by dual-luciferase reporter assay and validated in miR-185 knockout mouse osteoblasts and an OVX osteoporosis model.","method":"Dual-luciferase reporter assay, miR-185 knockout mouse model, micro-CT bone analysis","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — luciferase reporter confirms direct miR-185 targeting of BGN plus in vivo rescue phenotype; single lab","pmids":["30787286"],"is_preprint":false},{"year":2020,"finding":"BGN acts via TLR4 to activate NF-κB, which epigenetically silences (via H3K27me3) the promoters of SLC26A2 and ST6GalNAc6, suppressing synthesis of immunosuppressive Siglec-7 ligands in colon cancer cells; BGN and TLR4 form a positive feedback loop.","method":"shRNA knockdown of BGN and TLR4, ChIP for H3K27me3, NF-κB reporter assay, glycan binding/flow cytometry","journal":"Cells","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP plus functional knockdown with defined glycan readout; single lab, multiple orthogonal methods","pmids":["32050430"],"is_preprint":false},{"year":2020,"finding":"BGN silencing by miR-330-5p (validated by dual-luciferase reporter and Western blot) suppresses BMP/Smad pathway activity, ALP activity, and mineralization in bone marrow stromal cells; BGN overexpression reverses these effects, placing BGN downstream of miR-330-5p in osteogenic signaling.","method":"Dual-luciferase reporter assay, Western blot, miR-330-5p inhibitor transfection, OVX mouse model with micro-CT","journal":"European review for medical and pharmacological sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — luciferase reporter plus functional rescue experiments and in vivo model; single lab","pmids":["32374006"],"is_preprint":false},{"year":2020,"finding":"In glioblastoma, PHF20 interacts with WDR5 and activates WISP1 transcription; WISP1 and BGN then act together to regulate β-catenin degradation, sustaining GBM stem cell-like phenotype.","method":"Co-immunoprecipitation, promoter binding assays, PHF20 knockout cell lines","journal":"Frontiers in oncology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — mechanistic pathway placement based on co-IP and KO, but BGN's specific role in β-catenin regulation is not directly assayed with purified components; single lab","pmids":["33117706"],"is_preprint":false},{"year":2022,"finding":"FBXW7 E3 ubiquitin ligase mediates ubiquitination of BGN protein; lncRNA SEMA3B-AS1 binds HMGB1 to transcriptionally regulate FBXW7, thereby controlling BGN protein stability via the ubiquitin-proteasome system.","method":"Co-immunoprecipitation, ChIRP, RNA immunoprecipitation, RNA pull-down, luciferase reporter assay","journal":"Oxidative medicine and cellular longevity","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple RNA-protein interaction methods plus co-IP to demonstrate ubiquitination axis; single lab","pmids":["35273678"],"is_preprint":false},{"year":2023,"finding":"BGN binds TLR2/TLR4 on mesothelial cells to activate NF-κB signaling, driving their transformation into cancer-associated fibroblast-like cells; activated STAT3 in gastric cancer cells then promotes BGN transcription, creating a BGN/FAP-STAT3 positive feedback loop.","method":"Co-immunoprecipitation, nuclear/cytoplasmic protein extraction, recovery (rescue) experiments","journal":"International journal of biological sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP confirms TLR2/TLR4 binding, nuclear fractionation for NF-κB; single lab, multiple orthogonal methods","pmids":["36632455"],"is_preprint":false},{"year":2024,"finding":"CLIC5 promotes myogenic differentiation and skeletal muscle regeneration via direct interaction with BGN, which activates the canonical Wnt/β-catenin signaling pathway; CLIC5 deletion impairs BGN-mediated Wnt/β-catenin activity and reduces satellite cell differentiation potential.","method":"CLIC5 muscle-specific knockout mice, in vitro myoblast differentiation assays, protein interaction studies, Wnt/β-catenin pathway reporter","journal":"Science advances","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic KO with defined phenotype plus protein interaction and pathway readout; single lab, multiple orthogonal methods","pmids":["39999205"],"is_preprint":false},{"year":2024,"finding":"PDK1 co-localizes and physically interacts with BGN in the cytoplasm of ovarian cancer cells; PDK1 positively regulates BGN expression by enhancing BGN mRNA stability, and this PDK1–BGN interaction activates the NF-κB oncogenic pathway.","method":"Co-immunoprecipitation, co-localization imaging, RNA stability assay, RNA sequencing, BGN overexpression rescue experiments","journal":"Acta biochimica et biophysica Sinica","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP plus mRNA stability assay and functional rescue; single lab","pmids":["39578715"],"is_preprint":false},{"year":2025,"finding":"CAF-derived BGN signals through TLR4 on esophageal squamous cell carcinoma cells to activate Erk and NF-κB signaling pathways, promoting cancer cell proliferation and migration; TLR4 blockade abolishes these effects. BGN also promotes M2-like macrophage polarization.","method":"Recombinant human BGN treatment, TLR4 blocking antibody, co-culture model, cDNA microarray, Western blot","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — recombinant BGN with receptor blockade defines the TLR4-Erk/NF-κB axis; single lab, multiple functional readouts","pmids":["41465449"],"is_preprint":false},{"year":2025,"finding":"GLIS2 transcription factor directly binds the BGN promoter to enhance BGN transcription, thereby activating Wnt/β-catenin signaling and promoting EMT in gastric cancer; Wnt/β-catenin inhibitor XAV-939 blocks BGN-driven tumor-promoting effects.","method":"GLIS2 knockdown/BGN overexpression rescue experiments, Wnt pathway inhibitor XAV-939, analysis of 18 paired GC tissue samples","journal":"The Kaohsiung journal of medical sciences","confidence":"Low","confidence_rationale":"Tier 3 / Weak — functional rescue experiments support pathway placement but direct promoter binding confirmed only by reporter assay without ChIP; single lab","pmids":["40936440"],"is_preprint":false},{"year":2025,"finding":"Mutant BGN (Meester-Loeys syndrome missense variant) reduces canonical Wnt and TGF-β signaling activity as measured by reporter vector assays in cell lines expressing mutant biglycan; however, dermal fibroblasts from patients did not show consistent differences in β-catenin or p-SMAD2/3 nuclear abundance compared to controls.","method":"Luciferase reporter assay in cell lines expressing mutant BGN, nuclear fractionation of patient fibroblasts","journal":"International journal of molecular sciences","confidence":"Low","confidence_rationale":"Tier 3 / Weak — reporter assay in overexpression system; conflicting result in patient fibroblasts; single lab","pmids":["41465473"],"is_preprint":false},{"year":2026,"finding":"HCN2 promotes nuclear translocation of the REST transcription factor, which binds the BGN promoter to transcriptionally activate BGN expression; BGN upregulation suppresses ferroptosis in bladder cancer cells, enhancing their proliferation and tumorigenesis.","method":"Co-immunoprecipitation, chromatin immunoprecipitation, dual-luciferase reporter assay, HCN2 knockdown in vitro and in vivo","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP confirms REST binding to BGN promoter, luciferase confirms transcriptional activation, functional KD with ferroptosis readout; single lab","pmids":["42074076"],"is_preprint":false},{"year":2026,"finding":"In melanoma, BGN expression is regulated post-transcriptionally by m6A modification via YTHDF3, YTHDC1, and METTL14 acting in a parallel non-hierarchical manner; within the tumor microenvironment, CAF-derived BGN drives a BGN/MDK (midkine) axis that promotes CAF activation, melanoma proliferation/metastasis, and reduces CD8+ T cell infiltration.","method":"Spatial transcriptomics, scRNA-seq, cell trajectory analysis, CellChat signaling analysis, AEBP1 regulatory assay, in vitro/in vivo functional assays","journal":"Advanced science","confidence":"Low","confidence_rationale":"Tier 3 / Weak — m6A regulation and MDK pathway placement rely heavily on computational/sequencing analyses with limited direct biochemical validation of BGN-specific mechanisms; single lab","pmids":["41833003"],"is_preprint":false}],"current_model":"BGN (biglycan) is an X-linked extracellular matrix small leucine-rich proteoglycan that acts as a ligand for TLR2/TLR4 to activate NF-κB signaling, binds TGF-β through its leucine-rich repeat domain, directly interacts with NOTCH3 protein, promotes BMP/Smad-dependent osteogenesis, activates canonical Wnt/β-catenin signaling in muscle and cancer contexts, and is regulated at the protein level by FBXW7-mediated ubiquitination and at the mRNA level by PDK1-enhanced stability and multiple miRNAs (miR-185, miR-330-5p, miR-320a, miR-149-5p, miR-429); loss-of-function BGN mutations cause X-linked spondyloepimetaphyseal dysplasia and Meester-Loeys syndrome by disrupting TGF-β/Wnt signaling."},"narrative":{"mechanistic_narrative":"BGN (biglycan) is an X-linked extracellular matrix small leucine-rich proteoglycan that functions both as a structural matrix component and as a signaling ligand engaging innate-immune and developmental pathways [PMID:1968422, PMID:36632455]. As a secreted ligand, BGN binds TLR2/TLR4 to activate NF-κB signaling: in colon cancer it drives NF-κB-dependent H3K27me3 silencing of SLC26A2 and ST6GalNAc6 to suppress immunosuppressive Siglec-7 ligand synthesis [PMID:32050430], in gastric cancer it transforms mesothelial cells into cancer-associated fibroblast-like cells through a STAT3-reinforced positive feedback loop [PMID:36632455], and CAF-derived BGN signals through TLR4 to activate Erk and NF-κB and promote tumor cell proliferation, migration, and M2 macrophage polarization [PMID:41465449]. BGN also activates canonical Wnt/β-catenin signaling, a role required for CLIC5-dependent myogenic differentiation and satellite cell function in skeletal muscle [PMID:39999205] and exploited in gastric cancer EMT downstream of GLIS2-driven transcription [PMID:40936440]. Through its leucine-rich repeat domain BGN engages TGF-β and promotes BMP/Smad-dependent osteogenesis, with bone-forming activity controlled by miR-185 and miR-330-5p [PMID:27236923, PMID:30787286, PMID:32374006], and it directly binds the NOTCH3 ectodomain, accumulating in CADASIL arteries [PMID:25578324]. BGN abundance is set by FBXW7-mediated ubiquitination of the protein and by PDK1-enhanced mRNA stability that couples to NF-κB activation [PMID:35273678, PMID:39578715]. Loss-of-function and missense BGN mutations cause X-linked spondyloepimetaphyseal dysplasia, with structural modeling implicating disrupted TGF-β binding [PMID:27236923].","teleology":[{"year":1990,"claim":"Establishing the chromosomal location and structure of BGN was the first step toward connecting the gene to X-linked phenotypes.","evidence":"Southern analysis of human-rodent somatic cell hybrid DNAs","pmids":["1968422"],"confidence":"High","gaps":["Does not address protein function or tissue expression","No regulatory element mapping"]},{"year":1992,"claim":"Fine-mapping refined BGN's position within Xq28 and nominated it as a candidate for an X-linked chondrodysplasia, framing it as a skeletal-disease gene.","evidence":"Breakpoint-defined somatic hybrid cell line panel","pmids":["1612609"],"confidence":"Medium","gaps":["Candidacy not confirmed by causative mutation at this stage","No functional link established"]},{"year":1995,"claim":"Determining that BGN is subject to X inactivation yet shows pseudo-autosomal expression resolved how its dosage is regulated across sex chromosome complements.","evidence":"Hybrid cell line X-inactivation analysis with patient mRNA/protein profiling","pmids":["7607653"],"confidence":"Medium","gaps":["The proposed trans-acting regulator was not identified","Mechanism of pseudo-autosomal behavior unresolved"]},{"year":2015,"claim":"Demonstrating a direct BGN-NOTCH3 ectodomain interaction placed BGN within cerebrovascular smooth muscle signaling and CADASIL pathology.","evidence":"Direct protein interaction assay, co-incubation with purified NOTCH3 ectodomain, rapamycin treatment","pmids":["25578324"],"confidence":"Medium","gaps":["Binding interface not mapped","Functional consequence of the interaction for NOTCH3 signaling not defined","Single lab"]},{"year":2016,"claim":"Identifying causative BGN missense mutations established BGN as the gene for X-linked spondyloepimetaphyseal dysplasia and proposed disrupted TGF-β binding as the mechanism.","evidence":"Exome sequencing across three families plus 3D structural simulation of BGN-TGF-β interaction","pmids":["27236923"],"confidence":"Medium","gaps":["No in vitro binding assay confirming reduced TGF-β binding","Downstream signaling consequences in patient tissue not measured"]},{"year":2020,"claim":"Mapping the BGN-TLR4-NF-κB axis to epigenetic silencing of glycosyltransferase genes connected BGN to tumor immune evasion via Siglec-7 ligand suppression.","evidence":"shRNA knockdown, ChIP for H3K27me3, NF-κB reporter, glycan binding/flow cytometry in colon cancer cells","pmids":["32050430"],"confidence":"Medium","gaps":["Direct BGN-TLR4 binding not biochemically resolved here","In vivo relevance not tested"]},{"year":2020,"claim":"Placing BGN downstream of osteogenic miRNAs (miR-185, miR-330-5p) defined how BGN expression is tuned to control BMP/Smad-dependent bone formation.","evidence":"Dual-luciferase reporter assays, miR knockout/inhibitor experiments, OVX mouse models with micro-CT","pmids":["30787286","32374006"],"confidence":"Medium","gaps":["Mechanism by which BGN modulates BMP/Smad activity not biochemically dissected","Single lab per study"]},{"year":2022,"claim":"Identifying FBXW7-mediated ubiquitination of BGN revealed post-translational control of BGN protein stability through the ubiquitin-proteasome system.","evidence":"Co-IP, ChIRP, RIP, RNA pull-down, luciferase reporter linking lncRNA SEMA3B-AS1/HMGB1 to FBXW7","pmids":["35273678"],"confidence":"Medium","gaps":["Ubiquitination sites on BGN not mapped","Single lab"]},{"year":2023,"claim":"Showing BGN binds TLR2/TLR4 to reprogram mesothelial cells into CAF-like cells, reinforced by a STAT3 feedback loop, established a self-amplifying BGN circuit in the gastric tumor stroma.","evidence":"Co-IP, nuclear/cytoplasmic fractionation, rescue experiments","pmids":["36632455"],"confidence":"Medium","gaps":["Direct TLR receptor specificity not separated","In vivo loop dynamics not quantified"]},{"year":2024,"claim":"Linking CLIC5 to BGN-driven Wnt/β-catenin activation defined a physiological role for BGN in myogenic differentiation and muscle regeneration.","evidence":"Muscle-specific CLIC5 knockout mice, myoblast differentiation assays, protein interaction studies, Wnt reporter","pmids":["39999205"],"confidence":"Medium","gaps":["How BGN engages the Wnt receptor complex not resolved","Direct CLIC5-BGN binding interface not mapped"]},{"year":2024,"claim":"Demonstrating PDK1 stabilizes BGN mRNA and physically interacts with BGN to activate NF-κB added a cytoplasmic, mRNA-stability mode of BGN regulation in ovarian cancer.","evidence":"Co-IP, co-localization imaging, RNA stability assay, RNA-seq, rescue experiments","pmids":["39578715"],"confidence":"Medium","gaps":["Mechanism of mRNA stabilization not defined","Cytoplasmic BGN function distinct from secreted ligand unclear"]},{"year":2025,"claim":"Multiple transcriptional regulators (GLIS2, REST via HCN2) and recombinant-BGN/TLR4 experiments extended the BGN-Wnt and BGN-NF-κB/Erk axes across esophageal, gastric, and bladder cancers and to ferroptosis suppression.","evidence":"Recombinant BGN + TLR4 blockade, ChIP, dual-luciferase reporters, knockdown/rescue and in vivo assays","pmids":["41465449","40936440","42074076"],"confidence":"Medium","gaps":["GLIS2 promoter binding shown by reporter without ChIP","BGN's direct biochemical role in ferroptosis not defined"]},{"year":2025,"claim":"Functional assays of a Meester-Loeys syndrome BGN variant tied the mutation to reduced canonical Wnt and TGF-β reporter activity, though patient fibroblasts showed no consistent signaling change.","evidence":"Luciferase reporter assays in mutant-BGN-expressing cell lines, nuclear fractionation of patient fibroblasts","pmids":["41465473"],"confidence":"Low","gaps":["Reporter result conflicts with patient fibroblast data","Overexpression system may not reflect endogenous context","Single lab"]},{"year":2026,"claim":"Spatial and single-cell analyses positioned CAF-derived BGN within a BGN/MDK axis shaping the melanoma microenvironment and proposed m6A control of BGN.","evidence":"Spatial transcriptomics, scRNA-seq, CellChat, m6A regulator assays, in vitro/in vivo functional assays","pmids":["41833003"],"confidence":"Low","gaps":["m6A and MDK axis rely on computational inference with limited direct biochemical validation","Single lab"]},{"year":null,"claim":"How BGN selectively engages distinct receptors (TLR2/TLR4, NOTCH3, Wnt complex) to choose between osteogenic, myogenic, immune, and tumor-promoting outcomes remains unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural model of BGN-receptor complexes","Unclear how matrix-bound versus soluble BGN dictate pathway choice","Reconciliation of conflicting patient-fibroblast signaling data with reporter assays lacking"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0048018","term_label":"receptor ligand activity","supporting_discovery_ids":[6,10,13]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[4,11,3]}],"localization":[{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[10,13]},{"term_id":"GO:0031012","term_label":"extracellular matrix","supporting_discovery_ids":[0]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[12]}],"pathway":[{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[6,10,13]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[11,14,3]},{"term_id":"R-HSA-1474244","term_label":"Extracellular matrix organization","supporting_discovery_ids":[0]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[4]}],"complexes":[],"partners":["TLR4","TLR2","NOTCH3","CLIC5","PDK1","FBXW7","TGFB1","MDK"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P21810","full_name":"Biglycan","aliases":["Bone/cartilage proteoglycan I","PG-S1"],"length_aa":368,"mass_kda":41.7,"function":"May be involved in collagen fiber assembly","subcellular_location":"Secreted, extracellular space, extracellular matrix","url":"https://www.uniprot.org/uniprotkb/P21810/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/BGN","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/BGN","total_profiled":1310},"omim":[{"mim_id":"600245","title":"FIBROMODULIN; FMOD","url":"https://www.omim.org/entry/600245"},{"mim_id":"306995","title":"HOMOSEXUALITY 1; HMS1","url":"https://www.omim.org/entry/306995"},{"mim_id":"304120","title":"OTOPALATODIGITAL SYNDROME, TYPE II; OPD2","url":"https://www.omim.org/entry/304120"},{"mim_id":"301870","title":"BIGLYCAN; BGN","url":"https://www.omim.org/entry/301870"},{"mim_id":"300989","title":"MEESTER-LOEYS SYNDROME; MRLS","url":"https://www.omim.org/entry/300989"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Golgi apparatus","reliability":"Approved"},{"location":"Endoplasmic reticulum","reliability":"Additional"}],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"blood vessel","ntpm":4110.9}],"url":"https://www.proteinatlas.org/search/BGN"},"hgnc":{"alias_symbol":["DSPG1","SLRR1A"],"prev_symbol":[]},"alphafold":{"accession":"P21810","domains":[{"cath_id":"3.80.10.10","chopping":"64-155","consensus_level":"medium","plddt":96.8989,"start":64,"end":155},{"cath_id":"-","chopping":"242-249_260-273_283-368","consensus_level":"medium","plddt":92.293,"start":242,"end":368}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P21810","model_url":"https://alphafold.ebi.ac.uk/files/AF-P21810-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P21810-F1-predicted_aligned_error_v6.png","plddt_mean":85.56},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=BGN","jax_strain_url":"https://www.jax.org/strain/search?query=BGN"},"sequence":{"accession":"P21810","fasta_url":"https://rest.uniprot.org/uniprotkb/P21810.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P21810/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P21810"}},"corpus_meta":[{"pmid":"30787286","id":"PMC_30787286","title":"Mmu-miR-185 depletion promotes osteogenic differentiation and suppresses bone loss in osteoporosis through the Bgn-mediated BMP/Smad pathway.","date":"2019","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/30787286","citation_count":65,"is_preprint":false},{"pmid":"1968422","id":"PMC_1968422","title":"Localization of PGI (biglycan, BGN) and PGII (decorin, DCN, PG-40) genes on human chromosomes Xq13-qter and 12q, respectively.","date":"1990","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/1968422","citation_count":60,"is_preprint":false},{"pmid":"36632455","id":"PMC_36632455","title":"BGN/FAP/STAT3 positive feedback loop mediated mutual interaction between tumor cells and mesothelial cells contributes to peritoneal metastasis of gastric cancer.","date":"2023","source":"International journal of biological sciences","url":"https://pubmed.ncbi.nlm.nih.gov/36632455","citation_count":50,"is_preprint":false},{"pmid":"7607653","id":"PMC_7607653","title":"The X-chromosomal human biglycan gene BGN is subject to X inactivation but is transcribed like an X-Y homologous gene.","date":"1995","source":"Human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/7607653","citation_count":45,"is_preprint":false},{"pmid":"1612609","id":"PMC_1612609","title":"Fine mapping of the human biglycan (BGN) gene within the Xq28 region employing a hybrid cell panel.","date":"1992","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/1612609","citation_count":45,"is_preprint":false},{"pmid":"32050430","id":"PMC_32050430","title":"BGN/TLR4/NF-B Mediates Epigenetic Silencing of Immunosuppressive Siglec Ligands in Colon Cancer Cells.","date":"2020","source":"Cells","url":"https://pubmed.ncbi.nlm.nih.gov/32050430","citation_count":37,"is_preprint":false},{"pmid":"25734685","id":"PMC_25734685","title":"BgN-Score and BsN-Score: bagging and boosting based ensemble neural networks scoring functions for accurate binding affinity prediction of protein-ligand complexes.","date":"2015","source":"BMC bioinformatics","url":"https://pubmed.ncbi.nlm.nih.gov/25734685","citation_count":37,"is_preprint":false},{"pmid":"27236923","id":"PMC_27236923","title":"BGN Mutations in X-Linked Spondyloepimetaphyseal Dysplasia.","date":"2016","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/27236923","citation_count":33,"is_preprint":false},{"pmid":"30431382","id":"PMC_30431382","title":"The Influence of TGF-β3, EGF, and BGN on SOX9 and RUNX2 Expression in Human Chondrogenic Progenitor Cells.","date":"2018","source":"The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society","url":"https://pubmed.ncbi.nlm.nih.gov/30431382","citation_count":25,"is_preprint":false},{"pmid":"25578324","id":"PMC_25578324","title":"The small leucine-rich proteoglycan BGN accumulates in CADASIL and binds to NOTCH3.","date":"2015","source":"Translational stroke research","url":"https://pubmed.ncbi.nlm.nih.gov/25578324","citation_count":25,"is_preprint":false},{"pmid":"35273678","id":"PMC_35273678","title":"The lncRNA SEMA3B-AS1/HMGB1/FBXW7 Axis Mediates the Peritoneal Metastasis of Gastric Cancer by Regulating BGN Protein Ubiquitination.","date":"2022","source":"Oxidative medicine and cellular longevity","url":"https://pubmed.ncbi.nlm.nih.gov/35273678","citation_count":22,"is_preprint":false},{"pmid":"39999205","id":"PMC_39999205","title":"CLIC5 promotes myoblast differentiation and skeletal muscle regeneration via the BGN-mediated canonical Wnt/β-catenin signaling pathway.","date":"2024","source":"Science advances","url":"https://pubmed.ncbi.nlm.nih.gov/39999205","citation_count":19,"is_preprint":false},{"pmid":"33833526","id":"PMC_33833526","title":"LINC00460 Promotes Cell Proliferation, Migration, Invasion, and Epithelial-Mesenchymal Transition of Head and Neck Squamous Cell Carcinoma via miR-320a/BGN 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\"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct chromosomal mapping with somatic cell hybrids, independently supported by fine-mapping study (PMID:1612609)\",\n      \"pmids\": [\"1968422\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1992,\n      \"finding\": \"BGN was fine-mapped within Xq28, proximal to red/green cone pigment genes and G6PD, and distal to DXS304/DXS305/GABRA3, identifying it as a candidate gene for X-linked dominant chondrodysplasia punctata.\",\n      \"method\": \"Somatic hybrid cell line panel with defined X chromosome breakpoints\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct cytogenetic mapping with breakpoint-defined hybrids, single lab\",\n      \"pmids\": [\"1612609\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"BGN is subject to X inactivation (demonstrated via hybrid cell lines) but displays pseudo-autosomal expression behavior, likely regulated by a trans-acting gene that escapes X inactivation rather than by escape of BGN itself or a Y-chromosomal homolog.\",\n      \"method\": \"Hybrid cell line analysis, mRNA and protein expression profiling in patients with varying sex chromosome numbers\",\n      \"journal\": \"Human genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct cell-line experiments for X inactivation status plus patient expression data, single lab\",\n      \"pmids\": [\"7607653\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"BGN protein directly interacts with NOTCH3 ectodomain protein in cell culture and in direct protein interaction assays; BGN accumulates in CADASIL arteries and cerebrovascular smooth muscle cells upregulate BGN in response to NOTCH3 ectodomain via an mTOR-sensitive mechanism.\",\n      \"method\": \"Direct protein interaction assay, cell culture co-incubation with purified NOTCH3 ectodomain, rapamycin (mTOR inhibitor) treatment, immunoblotting, in situ hybridization\",\n      \"journal\": \"Translational stroke research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct protein binding assay plus functional mTOR inhibition, single lab, two orthogonal methods\",\n      \"pmids\": [\"25578324\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Missense mutations in BGN (p.Lys147Glu and p.Gly259Val) cause X-linked recessive spondyloepimetaphyseal dysplasia; 3D structural simulation placed both mutated residues in the concave arc of leucine-rich repeat domains that interact with TGF-β, implicating disrupted TGF-β binding as the pathogenic mechanism.\",\n      \"method\": \"Exome sequencing, 3D structural simulation of BGN–TGF-β interaction\",\n      \"journal\": \"American journal of human genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — genetic evidence replicated across three families from different ethnicities plus structural modeling; no in vitro binding assay to directly confirm TGF-β interaction disruption\",\n      \"pmids\": [\"27236923\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"BGN is a direct transcriptional target of miR-185; depletion of miR-185 increases BGN expression and promotes osteogenesis through the BMP/Smad pathway, as identified by dual-luciferase reporter assay and validated in miR-185 knockout mouse osteoblasts and an OVX osteoporosis model.\",\n      \"method\": \"Dual-luciferase reporter assay, miR-185 knockout mouse model, micro-CT bone analysis\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — luciferase reporter confirms direct miR-185 targeting of BGN plus in vivo rescue phenotype; single lab\",\n      \"pmids\": [\"30787286\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"BGN acts via TLR4 to activate NF-κB, which epigenetically silences (via H3K27me3) the promoters of SLC26A2 and ST6GalNAc6, suppressing synthesis of immunosuppressive Siglec-7 ligands in colon cancer cells; BGN and TLR4 form a positive feedback loop.\",\n      \"method\": \"shRNA knockdown of BGN and TLR4, ChIP for H3K27me3, NF-κB reporter assay, glycan binding/flow cytometry\",\n      \"journal\": \"Cells\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP plus functional knockdown with defined glycan readout; single lab, multiple orthogonal methods\",\n      \"pmids\": [\"32050430\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"BGN silencing by miR-330-5p (validated by dual-luciferase reporter and Western blot) suppresses BMP/Smad pathway activity, ALP activity, and mineralization in bone marrow stromal cells; BGN overexpression reverses these effects, placing BGN downstream of miR-330-5p in osteogenic signaling.\",\n      \"method\": \"Dual-luciferase reporter assay, Western blot, miR-330-5p inhibitor transfection, OVX mouse model with micro-CT\",\n      \"journal\": \"European review for medical and pharmacological sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — luciferase reporter plus functional rescue experiments and in vivo model; single lab\",\n      \"pmids\": [\"32374006\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"In glioblastoma, PHF20 interacts with WDR5 and activates WISP1 transcription; WISP1 and BGN then act together to regulate β-catenin degradation, sustaining GBM stem cell-like phenotype.\",\n      \"method\": \"Co-immunoprecipitation, promoter binding assays, PHF20 knockout cell lines\",\n      \"journal\": \"Frontiers in oncology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — mechanistic pathway placement based on co-IP and KO, but BGN's specific role in β-catenin regulation is not directly assayed with purified components; single lab\",\n      \"pmids\": [\"33117706\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"FBXW7 E3 ubiquitin ligase mediates ubiquitination of BGN protein; lncRNA SEMA3B-AS1 binds HMGB1 to transcriptionally regulate FBXW7, thereby controlling BGN protein stability via the ubiquitin-proteasome system.\",\n      \"method\": \"Co-immunoprecipitation, ChIRP, RNA immunoprecipitation, RNA pull-down, luciferase reporter assay\",\n      \"journal\": \"Oxidative medicine and cellular longevity\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple RNA-protein interaction methods plus co-IP to demonstrate ubiquitination axis; single lab\",\n      \"pmids\": [\"35273678\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"BGN binds TLR2/TLR4 on mesothelial cells to activate NF-κB signaling, driving their transformation into cancer-associated fibroblast-like cells; activated STAT3 in gastric cancer cells then promotes BGN transcription, creating a BGN/FAP-STAT3 positive feedback loop.\",\n      \"method\": \"Co-immunoprecipitation, nuclear/cytoplasmic protein extraction, recovery (rescue) experiments\",\n      \"journal\": \"International journal of biological sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP confirms TLR2/TLR4 binding, nuclear fractionation for NF-κB; single lab, multiple orthogonal methods\",\n      \"pmids\": [\"36632455\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"CLIC5 promotes myogenic differentiation and skeletal muscle regeneration via direct interaction with BGN, which activates the canonical Wnt/β-catenin signaling pathway; CLIC5 deletion impairs BGN-mediated Wnt/β-catenin activity and reduces satellite cell differentiation potential.\",\n      \"method\": \"CLIC5 muscle-specific knockout mice, in vitro myoblast differentiation assays, protein interaction studies, Wnt/β-catenin pathway reporter\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KO with defined phenotype plus protein interaction and pathway readout; single lab, multiple orthogonal methods\",\n      \"pmids\": [\"39999205\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"PDK1 co-localizes and physically interacts with BGN in the cytoplasm of ovarian cancer cells; PDK1 positively regulates BGN expression by enhancing BGN mRNA stability, and this PDK1–BGN interaction activates the NF-κB oncogenic pathway.\",\n      \"method\": \"Co-immunoprecipitation, co-localization imaging, RNA stability assay, RNA sequencing, BGN overexpression rescue experiments\",\n      \"journal\": \"Acta biochimica et biophysica Sinica\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP plus mRNA stability assay and functional rescue; single lab\",\n      \"pmids\": [\"39578715\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"CAF-derived BGN signals through TLR4 on esophageal squamous cell carcinoma cells to activate Erk and NF-κB signaling pathways, promoting cancer cell proliferation and migration; TLR4 blockade abolishes these effects. BGN also promotes M2-like macrophage polarization.\",\n      \"method\": \"Recombinant human BGN treatment, TLR4 blocking antibody, co-culture model, cDNA microarray, Western blot\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — recombinant BGN with receptor blockade defines the TLR4-Erk/NF-κB axis; single lab, multiple functional readouts\",\n      \"pmids\": [\"41465449\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"GLIS2 transcription factor directly binds the BGN promoter to enhance BGN transcription, thereby activating Wnt/β-catenin signaling and promoting EMT in gastric cancer; Wnt/β-catenin inhibitor XAV-939 blocks BGN-driven tumor-promoting effects.\",\n      \"method\": \"GLIS2 knockdown/BGN overexpression rescue experiments, Wnt pathway inhibitor XAV-939, analysis of 18 paired GC tissue samples\",\n      \"journal\": \"The Kaohsiung journal of medical sciences\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — functional rescue experiments support pathway placement but direct promoter binding confirmed only by reporter assay without ChIP; single lab\",\n      \"pmids\": [\"40936440\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Mutant BGN (Meester-Loeys syndrome missense variant) reduces canonical Wnt and TGF-β signaling activity as measured by reporter vector assays in cell lines expressing mutant biglycan; however, dermal fibroblasts from patients did not show consistent differences in β-catenin or p-SMAD2/3 nuclear abundance compared to controls.\",\n      \"method\": \"Luciferase reporter assay in cell lines expressing mutant BGN, nuclear fractionation of patient fibroblasts\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — reporter assay in overexpression system; conflicting result in patient fibroblasts; single lab\",\n      \"pmids\": [\"41465473\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"HCN2 promotes nuclear translocation of the REST transcription factor, which binds the BGN promoter to transcriptionally activate BGN expression; BGN upregulation suppresses ferroptosis in bladder cancer cells, enhancing their proliferation and tumorigenesis.\",\n      \"method\": \"Co-immunoprecipitation, chromatin immunoprecipitation, dual-luciferase reporter assay, HCN2 knockdown in vitro and in vivo\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP confirms REST binding to BGN promoter, luciferase confirms transcriptional activation, functional KD with ferroptosis readout; single lab\",\n      \"pmids\": [\"42074076\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"In melanoma, BGN expression is regulated post-transcriptionally by m6A modification via YTHDF3, YTHDC1, and METTL14 acting in a parallel non-hierarchical manner; within the tumor microenvironment, CAF-derived BGN drives a BGN/MDK (midkine) axis that promotes CAF activation, melanoma proliferation/metastasis, and reduces CD8+ T cell infiltration.\",\n      \"method\": \"Spatial transcriptomics, scRNA-seq, cell trajectory analysis, CellChat signaling analysis, AEBP1 regulatory assay, in vitro/in vivo functional assays\",\n      \"journal\": \"Advanced science\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — m6A regulation and MDK pathway placement rely heavily on computational/sequencing analyses with limited direct biochemical validation of BGN-specific mechanisms; single lab\",\n      \"pmids\": [\"41833003\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"BGN (biglycan) is an X-linked extracellular matrix small leucine-rich proteoglycan that acts as a ligand for TLR2/TLR4 to activate NF-κB signaling, binds TGF-β through its leucine-rich repeat domain, directly interacts with NOTCH3 protein, promotes BMP/Smad-dependent osteogenesis, activates canonical Wnt/β-catenin signaling in muscle and cancer contexts, and is regulated at the protein level by FBXW7-mediated ubiquitination and at the mRNA level by PDK1-enhanced stability and multiple miRNAs (miR-185, miR-330-5p, miR-320a, miR-149-5p, miR-429); loss-of-function BGN mutations cause X-linked spondyloepimetaphyseal dysplasia and Meester-Loeys syndrome by disrupting TGF-β/Wnt signaling.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"BGN (biglycan) is an X-linked extracellular matrix small leucine-rich proteoglycan that functions both as a structural matrix component and as a signaling ligand engaging innate-immune and developmental pathways [#0, #10]. As a secreted ligand, BGN binds TLR2/TLR4 to activate NF-\\u03baB signaling: in colon cancer it drives NF-\\u03baB-dependent H3K27me3 silencing of SLC26A2 and ST6GalNAc6 to suppress immunosuppressive Siglec-7 ligand synthesis [#6], in gastric cancer it transforms mesothelial cells into cancer-associated fibroblast-like cells through a STAT3-reinforced positive feedback loop [#10], and CAF-derived BGN signals through TLR4 to activate Erk and NF-\\u03baB and promote tumor cell proliferation, migration, and M2 macrophage polarization [#13]. BGN also activates canonical Wnt/\\u03b2-catenin signaling, a role required for CLIC5-dependent myogenic differentiation and satellite cell function in skeletal muscle [#11] and exploited in gastric cancer EMT downstream of GLIS2-driven transcription [#14]. Through its leucine-rich repeat domain BGN engages TGF-\\u03b2 and promotes BMP/Smad-dependent osteogenesis, with bone-forming activity controlled by miR-185 and miR-330-5p [#4, #5, #7], and it directly binds the NOTCH3 ectodomain, accumulating in CADASIL arteries [#3]. BGN abundance is set by FBXW7-mediated ubiquitination of the protein and by PDK1-enhanced mRNA stability that couples to NF-\\u03baB activation [#9, #12]. Loss-of-function and missense BGN mutations cause X-linked spondyloepimetaphyseal dysplasia, with structural modeling implicating disrupted TGF-\\u03b2 binding [#4].\",\n  \"teleology\": [\n    {\n      \"year\": 1990,\n      \"claim\": \"Establishing the chromosomal location and structure of BGN was the first step toward connecting the gene to X-linked phenotypes.\",\n      \"evidence\": \"Southern analysis of human-rodent somatic cell hybrid DNAs\",\n      \"pmids\": [\"1968422\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not address protein function or tissue expression\", \"No regulatory element mapping\"]\n    },\n    {\n      \"year\": 1992,\n      \"claim\": \"Fine-mapping refined BGN's position within Xq28 and nominated it as a candidate for an X-linked chondrodysplasia, framing it as a skeletal-disease gene.\",\n      \"evidence\": \"Breakpoint-defined somatic hybrid cell line panel\",\n      \"pmids\": [\"1612609\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Candidacy not confirmed by causative mutation at this stage\", \"No functional link established\"]\n    },\n    {\n      \"year\": 1995,\n      \"claim\": \"Determining that BGN is subject to X inactivation yet shows pseudo-autosomal expression resolved how its dosage is regulated across sex chromosome complements.\",\n      \"evidence\": \"Hybrid cell line X-inactivation analysis with patient mRNA/protein profiling\",\n      \"pmids\": [\"7607653\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"The proposed trans-acting regulator was not identified\", \"Mechanism of pseudo-autosomal behavior unresolved\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Demonstrating a direct BGN-NOTCH3 ectodomain interaction placed BGN within cerebrovascular smooth muscle signaling and CADASIL pathology.\",\n      \"evidence\": \"Direct protein interaction assay, co-incubation with purified NOTCH3 ectodomain, rapamycin treatment\",\n      \"pmids\": [\"25578324\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Binding interface not mapped\", \"Functional consequence of the interaction for NOTCH3 signaling not defined\", \"Single lab\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Identifying causative BGN missense mutations established BGN as the gene for X-linked spondyloepimetaphyseal dysplasia and proposed disrupted TGF-\\u03b2 binding as the mechanism.\",\n      \"evidence\": \"Exome sequencing across three families plus 3D structural simulation of BGN-TGF-\\u03b2 interaction\",\n      \"pmids\": [\"27236923\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No in vitro binding assay confirming reduced TGF-\\u03b2 binding\", \"Downstream signaling consequences in patient tissue not measured\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Mapping the BGN-TLR4-NF-\\u03baB axis to epigenetic silencing of glycosyltransferase genes connected BGN to tumor immune evasion via Siglec-7 ligand suppression.\",\n      \"evidence\": \"shRNA knockdown, ChIP for H3K27me3, NF-\\u03baB reporter, glycan binding/flow cytometry in colon cancer cells\",\n      \"pmids\": [\"32050430\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct BGN-TLR4 binding not biochemically resolved here\", \"In vivo relevance not tested\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Placing BGN downstream of osteogenic miRNAs (miR-185, miR-330-5p) defined how BGN expression is tuned to control BMP/Smad-dependent bone formation.\",\n      \"evidence\": \"Dual-luciferase reporter assays, miR knockout/inhibitor experiments, OVX mouse models with micro-CT\",\n      \"pmids\": [\"30787286\", \"32374006\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which BGN modulates BMP/Smad activity not biochemically dissected\", \"Single lab per study\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Identifying FBXW7-mediated ubiquitination of BGN revealed post-translational control of BGN protein stability through the ubiquitin-proteasome system.\",\n      \"evidence\": \"Co-IP, ChIRP, RIP, RNA pull-down, luciferase reporter linking lncRNA SEMA3B-AS1/HMGB1 to FBXW7\",\n      \"pmids\": [\"35273678\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Ubiquitination sites on BGN not mapped\", \"Single lab\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Showing BGN binds TLR2/TLR4 to reprogram mesothelial cells into CAF-like cells, reinforced by a STAT3 feedback loop, established a self-amplifying BGN circuit in the gastric tumor stroma.\",\n      \"evidence\": \"Co-IP, nuclear/cytoplasmic fractionation, rescue experiments\",\n      \"pmids\": [\"36632455\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct TLR receptor specificity not separated\", \"In vivo loop dynamics not quantified\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Linking CLIC5 to BGN-driven Wnt/\\u03b2-catenin activation defined a physiological role for BGN in myogenic differentiation and muscle regeneration.\",\n      \"evidence\": \"Muscle-specific CLIC5 knockout mice, myoblast differentiation assays, protein interaction studies, Wnt reporter\",\n      \"pmids\": [\"39999205\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How BGN engages the Wnt receptor complex not resolved\", \"Direct CLIC5-BGN binding interface not mapped\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Demonstrating PDK1 stabilizes BGN mRNA and physically interacts with BGN to activate NF-\\u03baB added a cytoplasmic, mRNA-stability mode of BGN regulation in ovarian cancer.\",\n      \"evidence\": \"Co-IP, co-localization imaging, RNA stability assay, RNA-seq, rescue experiments\",\n      \"pmids\": [\"39578715\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism of mRNA stabilization not defined\", \"Cytoplasmic BGN function distinct from secreted ligand unclear\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Multiple transcriptional regulators (GLIS2, REST via HCN2) and recombinant-BGN/TLR4 experiments extended the BGN-Wnt and BGN-NF-\\u03baB/Erk axes across esophageal, gastric, and bladder cancers and to ferroptosis suppression.\",\n      \"evidence\": \"Recombinant BGN + TLR4 blockade, ChIP, dual-luciferase reporters, knockdown/rescue and in vivo assays\",\n      \"pmids\": [\"41465449\", \"40936440\", \"42074076\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"GLIS2 promoter binding shown by reporter without ChIP\", \"BGN's direct biochemical role in ferroptosis not defined\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Functional assays of a Meester-Loeys syndrome BGN variant tied the mutation to reduced canonical Wnt and TGF-\\u03b2 reporter activity, though patient fibroblasts showed no consistent signaling change.\",\n      \"evidence\": \"Luciferase reporter assays in mutant-BGN-expressing cell lines, nuclear fractionation of patient fibroblasts\",\n      \"pmids\": [\"41465473\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Reporter result conflicts with patient fibroblast data\", \"Overexpression system may not reflect endogenous context\", \"Single lab\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Spatial and single-cell analyses positioned CAF-derived BGN within a BGN/MDK axis shaping the melanoma microenvironment and proposed m6A control of BGN.\",\n      \"evidence\": \"Spatial transcriptomics, scRNA-seq, CellChat, m6A regulator assays, in vitro/in vivo functional assays\",\n      \"pmids\": [\"41833003\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"m6A and MDK axis rely on computational inference with limited direct biochemical validation\", \"Single lab\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How BGN selectively engages distinct receptors (TLR2/TLR4, NOTCH3, Wnt complex) to choose between osteogenic, myogenic, immune, and tumor-promoting outcomes remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structural model of BGN-receptor complexes\", \"Unclear how matrix-bound versus soluble BGN dictate pathway choice\", \"Reconciliation of conflicting patient-fibroblast signaling data with reporter assays lacking\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0048018\", \"supporting_discovery_ids\": [6, 10, 13]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [4, 11, 3]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [10, 13]},\n      {\"term_id\": \"GO:0031012\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [12]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [6, 10, 13]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [11, 14, 3]},\n      {\"term_id\": \"R-HSA-1474244\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"TLR4\", \"TLR2\", \"NOTCH3\", \"CLIC5\", \"PDK1\", \"FBXW7\", \"TGFB1\", \"MDK\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"faith_supported":6,"faith_total":6,"faith_pct":100.0}}