{"gene":"ASPN","run_date":"2026-04-28T17:12:37","timeline":{"discoveries":[{"year":2007,"finding":"PLAP-1/asporin directly binds BMP-2 (shown by co-immunoprecipitation) and negatively regulates BMP-2-induced mineralization and cytodifferentiation of periodontal ligament cells; overexpression inhibits and knockdown enhances BMP-2-induced differentiation.","method":"Co-immunoprecipitation, overexpression, RNA interference, in vitro mineralization assay, immunohistochemistry","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — reciprocal Co-IP plus functional KD/OE with defined cellular phenotype, replicated in subsequent studies","pmids":["17522060"],"is_preprint":false},{"year":2008,"finding":"PLAP-1/asporin inhibits BMP-2 signaling by competitively preventing BMP-2 from binding BMPR-IB, thereby blocking Smad activation; the LRR5 motif within the leucine-rich repeat region is required for BMP-2 interaction, and a 26-amino acid LRR5 peptide is sufficient to inhibit BMP-2 activity.","method":"Recombinant protein competition binding assay, site-directed mutagenesis of LRR5, Smad phosphorylation western blot, peptide inhibition assay","journal":"Biochemical and biophysical research communications","confidence":"High","confidence_rationale":"Tier 1 — in vitro reconstituted competition assay plus mutagenesis identifying active LRR5 domain","pmids":["18407830"],"is_preprint":false},{"year":2015,"finding":"PLAP-1/asporin directly binds FGF-2 (shown by binding assay) and promotes formation of the FGF-2–FGFR1 complex, positively regulating FGF-2 signaling; Plap-1 knockout MEFs show defective FGF-2 responses rescued by Plap-1 re-introduction.","method":"Binding assay, co-immunoprecipitation, Plap-1 knockout MEFs, Plap-1 gene transfection rescue, immunocytochemistry colocalization","journal":"Journal of dental research","confidence":"High","confidence_rationale":"Tier 2 — direct binding assay, knockout rescue, and colocalization with multiple orthogonal methods","pmids":["26239644"],"is_preprint":false},{"year":2015,"finding":"PLAP-1/asporin directly binds TLR2 and TLR4 (shown by immunoprecipitation), suppresses NF-κB activation, reduces IκB kinase α degradation induced by TLR4, and inhibits TLR2/4-induced proinflammatory cytokine expression in periodontal ligament cells and macrophages.","method":"Immunoprecipitation, NF-κB luciferase reporter assay, recombinant protein treatment, overexpression, western blot (IκBα degradation)","journal":"Journal of dental research","confidence":"High","confidence_rationale":"Tier 2 — Co-IP binding, functional NF-κB reporter, and IκBα mechanistic readout with multiple cell types","pmids":["26399972"],"is_preprint":false},{"year":2014,"finding":"The D14 allele of the aspartic acid repeat polymorphism of PLAP-1/asporin shows stronger binding affinity to BMP-2 (by co-immunoprecipitation) and more potently suppresses BMP-2-induced differentiation and signal transduction in PDL cells compared with the D13 allele.","method":"Co-immunoprecipitation, BMP-2 signaling western blot, luciferase reporter assay, alkaline phosphatase and alizarin red staining","journal":"Journal of dental research","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods linking polymorphism to differential binding affinity and functional output","pmids":["24453179"],"is_preprint":false},{"year":2012,"finding":"miR-21 and miR-101 directly target the PLAP-1/asporin 3′UTR to repress its expression during osteogenic differentiation of periodontal ligament cells.","method":"Dual luciferase reporter assay, qRT-PCR, bioinformatic target prediction","journal":"Molecular medicine reports","confidence":"Medium","confidence_rationale":"Tier 2 — luciferase reporter validates direct targeting; single lab","pmids":["22367347"],"is_preprint":false},{"year":2019,"finding":"1,25(OH)2D3 transcriptionally suppresses PLAP-1 expression in human periodontal ligament stem cells through a vitamin D receptor element (VDRE) identified in the PLAP-1 promoter, validated by ChIP assay and reporter gene assay.","method":"ChIP assay, luciferase reporter assay, qRT-PCR, western blot","journal":"International immunopharmacology","confidence":"Medium","confidence_rationale":"Tier 2 — ChIP and reporter assay confirm VDR-VDRE interaction; single lab","pmids":["31837573"],"is_preprint":false},{"year":2022,"finding":"PLAP-1/asporin expression is upregulated in periodontal ligament cells under hypoxia via HIF-1α activation; reciprocally, recombinant PLAP-1 suppresses hypoxia-response element (HRE) reporter activity and HIF-1α nuclear accumulation in a dose-dependent manner, indicating a negative feedback loop.","method":"HRE-luciferase reporter assay, western blot (HIF-1α nuclear accumulation), recombinant protein treatment, PLAP-1 gene transfection, qRT-PCR","journal":"Journal of periodontal research","confidence":"Medium","confidence_rationale":"Tier 2 — reporter assay plus protein-level mechanistic readout; single lab","pmids":["35138637"],"is_preprint":false},{"year":2021,"finding":"PLAP-1/asporin enhances adipogenesis; Plap-1 knockout mice and Plap-1-knockdown 3T3-L1 cells show reduced lipid accumulation, while recombinant PLAP-1 enhances lipid accumulation, demonstrating a direct role in adipocyte differentiation.","method":"Plap-1 knockout mice, siRNA knockdown in 3T3-L1 cells, recombinant protein treatment, lipid accumulation assay, ECM gene expression profiling","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 — loss-of-function (KO and KD) plus gain-of-function (recombinant protein) with defined cellular phenotype","pmids":["33654143"],"is_preprint":false},{"year":2023,"finding":"PLAP-1/asporin regulates periodontal ligament collagen fibril diameter and ECM composition; PLAP-1 knockout mice display enlarged PDL space, increased collagen diameter (TEM), upregulated ECM proteins (Col3, BGN, DCN), reduced tooth extraction force, and accelerated alveolar bone loss in ligature-induced periodontitis with more osteoclasts.","method":"PLAP-1 knockout mice, micro-CT, histology (HE, picrosirius red), TEM of collagen fibrils, fluorescence immunostaining, tooth extraction force measurement, ligature periodontitis model","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 2 — KO with multiple orthogonal structural and functional readouts; single lab","pmids":["37958972"],"is_preprint":false},{"year":2023,"finding":"ASPN interacts with HAPLN1 (shown by protein interaction analysis and binding assay in BMSCs), and their combined knockdown synergistically promotes osteogenic differentiation of BMSCs and ECM mineralization of osteoblasts while reducing osteoclastogenesis.","method":"Co-immunoprecipitation/protein interaction assay, siRNA knockdown (individual and combined), ALP/osteogenic marker western blot, ECM mineralization assay, osteoclastogenesis assay in OVX mouse model","journal":"Orthopaedic surgery","confidence":"Medium","confidence_rationale":"Tier 3 — protein interaction plus functional KD; single lab","pmids":["37427673"],"is_preprint":false},{"year":2022,"finding":"PLAP-1/asporin lineage tracing in knock-in mice confirmed that Plap-1-positive periodontal ligament cells differentiate into osteoblasts and cementoblasts, and contribute to periodontal tissue regeneration after injury.","method":"CreERT2 knock-in lineage tracing, single-cell RNA sequencing, RNA velocity analysis, GFP reporter","journal":"Development (Cambridge, England)","confidence":"Medium","confidence_rationale":"Tier 2 — genetic lineage tracing with single-cell atlas; defines cell differentiation hierarchy","pmids":["36245218"],"is_preprint":false},{"year":2021,"finding":"miR-4303 directly targets ASPN mRNA (validated by dual-luciferase reporter assay), and miR-4303 overexpression reduces ASPN protein levels, rescuing LPS-induced chondrocyte inflammation, cell cycle arrest, and apoptosis.","method":"Dual-luciferase reporter assay, western blot, qRT-PCR, flow cytometry, ELISA","journal":"Journal of orthopaedic surgery and research","confidence":"Medium","confidence_rationale":"Tier 2 — luciferase reporter validates direct targeting; single lab with multiple functional readouts","pmids":["34663368"],"is_preprint":false},{"year":2024,"finding":"MATN3 directly interacts with ASPN (confirmed by protein-protein interaction and co-expression analyses), and ASPN overexpression amplifies MATN3-driven gastric cancer cell proliferation, migration, invasion, and EMT activation both in vitro and in vivo.","method":"Protein-protein interaction analysis, co-expression analysis, overexpression, siRNA knockdown, proliferation/migration/invasion assays, mouse xenograft model","journal":"Human molecular genetics","confidence":"Low","confidence_rationale":"Tier 3 — interaction supported by bioinformatics + functional assays; mechanistic detail limited","pmids":["39301785"],"is_preprint":false},{"year":2021,"finding":"lncRNA DCST1-AS1 binds the miR-21 precursor (not mature miR-21) to suppress miR-21 levels, thereby de-repressing PLAP-1/asporin expression and inhibiting periodontal ligament cell proliferation.","method":"qPCR, western blot, transfection experiments, CCK-8 proliferation assay, bioinformatics prediction","journal":"Journal of periodontal research","confidence":"Low","confidence_rationale":"Tier 3 — indirect mechanism inferred from expression rescue experiments; no direct binding validated biochemically","pmids":["33533513"],"is_preprint":false},{"year":2026,"finding":"Exosomal miR-143-5p from H. pylori-infected epithelial cells functions as a nuclear activating miRNA (NamiRNA) that binds the ASPN super-enhancer region, increases H3K27ac enrichment, and transcriptionally upregulates ASPN in fibroblasts, promoting downstream pro-inflammatory cytokine (IL-4, IL-6, TGF-β) expression.","method":"microRNA sequencing, immunofluorescence, co-culture assay, ChIP (H3K27ac), immunohistochemistry, antagomir in vivo","journal":"Gut pathogens","confidence":"Medium","confidence_rationale":"Tier 2 — ChIP validates super-enhancer binding; in vivo antagomir confirms pathway; single lab","pmids":["41723544"],"is_preprint":false}],"current_model":"ASPN (asporin/PLAP-1) is a secreted small leucine-rich repeat proteoglycan that acts as a multi-functional extracellular regulator: it directly binds BMP-2 via its LRR5 motif to competitively block BMPR-IB engagement and downstream Smad signaling (inhibiting osteogenic/chondrogenic differentiation), directly binds FGF-2 to promote FGF-2–FGFR1 complex formation (positively regulating FGF-2 signaling), directly binds TLR2 and TLR4 to suppress NF-κB/IκB kinase signaling and inflammatory cytokine production, modulates HIF-1α activity through a negative feedback loop under hypoxia, promotes adipogenesis, and regulates periodontal ligament collagen fibril architecture; its activity is subject to post-transcriptional regulation by miR-21 and miR-101, and transcriptional regulation by VDR and HIF-1α."},"narrative":{"teleology":[{"year":2007,"claim":"Establishing that asporin is not merely an extracellular matrix structural component but an active signaling modulator: direct binding to BMP-2 and functional inhibition of BMP-2-induced mineralization in periodontal ligament cells revealed a previously unknown antagonistic role for this SLRP.","evidence":"Co-immunoprecipitation of ASPN–BMP-2, overexpression/knockdown in PDL cells with mineralization readout","pmids":["17522060"],"confidence":"High","gaps":["Binding domain on ASPN not yet mapped","Mechanism of inhibition (competitive vs. allosteric) unknown","In vivo relevance not tested"]},{"year":2008,"claim":"Resolving the mechanism of BMP-2 antagonism: ASPN competitively prevents BMP-2 from engaging BMPR-IB through its LRR5 motif, and a 26-amino-acid LRR5 peptide is sufficient to block BMP-2 signaling, pinpointing the minimal inhibitory domain.","evidence":"Reconstituted competition binding assay with recombinant proteins, LRR5 mutagenesis, Smad phosphorylation western blot, peptide inhibition","pmids":["18407830"],"confidence":"High","gaps":["Structural basis of LRR5–BMP-2 interaction not determined","Whether other BMP family members are similarly antagonized is untested"]},{"year":2012,"claim":"Identifying a post-transcriptional regulatory layer: miR-21 and miR-101 directly target the ASPN 3′UTR to repress its expression during osteogenic differentiation, suggesting that ASPN levels are actively tuned to permit differentiation.","evidence":"Dual-luciferase reporter assay validating direct 3′UTR targeting in PDL cells","pmids":["22367347"],"confidence":"Medium","gaps":["Endogenous stoichiometric relevance of miR-mediated repression not quantified","Single lab without independent replication"]},{"year":2014,"claim":"Linking a natural polymorphism to differential signaling output: the D14 aspartic acid repeat allele shows stronger BMP-2 binding and greater suppression of BMP-2-driven differentiation than D13, providing a molecular basis for disease-association studies of this polymorphism.","evidence":"Co-immunoprecipitation comparing D13 vs D14 allelic variants, BMP-2 signaling reporter and differentiation assays","pmids":["24453179"],"confidence":"High","gaps":["Structural explanation for how additional aspartate residues increase affinity is absent","Population-level functional impact not directly measured"]},{"year":2015,"claim":"Demonstrating that ASPN is a dual-function signaling modulator with opposing effects on different pathways: it positively regulates FGF-2 signaling by promoting FGF-2–FGFR1 complex formation, and negatively regulates TLR2/TLR4-NF-κB inflammatory signaling by direct receptor binding.","evidence":"Direct binding assays, Plap-1 KO MEFs with rescue (FGF-2), immunoprecipitation of ASPN–TLR2/TLR4, NF-κB reporter and IκBα degradation readouts","pmids":["26239644","26399972"],"confidence":"High","gaps":["Domains on ASPN responsible for FGF-2 and TLR binding not mapped","Whether FGF-2 and TLR ligand binding are mutually exclusive is unknown","In vivo validation of anti-inflammatory function not performed"]},{"year":2019,"claim":"Uncovering transcriptional regulation of ASPN: vitamin D receptor directly binds a VDRE in the ASPN promoter and suppresses transcription, establishing a hormonal input controlling ASPN expression in periodontal tissues.","evidence":"ChIP assay confirming VDR occupancy at ASPN promoter, luciferase reporter in human PDL stem cells","pmids":["31837573"],"confidence":"Medium","gaps":["Whether VDR regulation extends to non-periodontal tissues is untested","Single lab"]},{"year":2021,"claim":"Extending ASPN function beyond mineralized tissue: ASPN positively regulates adipogenesis, as demonstrated by reduced lipid accumulation in knockout mice and knockdown adipocytes and enhanced accumulation with recombinant protein.","evidence":"Plap-1 KO mice, siRNA in 3T3-L1, recombinant ASPN gain-of-function, lipid accumulation assays","pmids":["33654143"],"confidence":"Medium","gaps":["Signaling pathway mediating pro-adipogenic effect not identified","Whether BMP-2 antagonism contributes to adipogenic shift is untested"]},{"year":2022,"claim":"Defining ASPN-expressing cells as a stem/progenitor population: lineage tracing showed that Plap-1-positive periodontal ligament cells differentiate into osteoblasts and cementoblasts and contribute to tissue regeneration after injury, establishing ASPN as a marker of a multipotent progenitor.","evidence":"CreERT2 knock-in lineage tracing, scRNA-seq, RNA velocity in mice","pmids":["36245218"],"confidence":"Medium","gaps":["Whether ASPN protein is functionally required for progenitor self-renewal or merely marks the population is unclear"]},{"year":2022,"claim":"Revealing a hypoxia–ASPN negative feedback loop: HIF-1α induces ASPN expression under hypoxia, while ASPN reciprocally suppresses HIF-1α nuclear accumulation and HRE transcriptional activity, suggesting homeostatic control of hypoxic responses.","evidence":"HRE-luciferase reporter, western blot for nuclear HIF-1α, recombinant ASPN dose-response in PDL cells","pmids":["35138637"],"confidence":"Medium","gaps":["Molecular mechanism by which extracellular ASPN reduces nuclear HIF-1α is unknown","Single lab"]},{"year":2023,"claim":"Establishing an in vivo structural role: ASPN knockout mice exhibit enlarged periodontal ligament space, increased collagen fibril diameter, altered ECM composition, reduced tooth anchorage, and accelerated bone loss with increased osteoclastogenesis in periodontitis.","evidence":"Plap-1 KO mice, micro-CT, TEM of collagen fibrils, ligature periodontitis model, tooth extraction force measurement","pmids":["37958972"],"confidence":"Medium","gaps":["Whether collagen fibril phenotype is cell-autonomous or secondary to altered signaling is unresolved","Molecular mechanism of osteoclastogenesis promotion not defined"]},{"year":null,"claim":"Key unresolved questions include: the structural basis of ASPN interactions with its multiple ligands (BMP-2, FGF-2, TLR2/4), whether distinct binding events are mutually exclusive or cooperative, the signaling pathway through which ASPN promotes adipogenesis, and the mechanism by which an extracellular protein suppresses nuclear HIF-1α accumulation.","evidence":"","pmids":[],"confidence":"High","gaps":["No crystal structure or cryo-EM model of ASPN or its complexes","No systematic mapping of which LRR domains mediate each interaction","Mechanism of HIF-1α suppression by an extracellular protein uncharacterized"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,1,2,3,4]},{"term_id":"GO:0048018","term_label":"receptor ligand activity","supporting_discovery_ids":[2]}],"localization":[{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[0,2,3,9]},{"term_id":"GO:0031012","term_label":"extracellular matrix","supporting_discovery_ids":[9]}],"pathway":[{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[3]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[0,1,11]}],"complexes":[],"partners":["BMP2","FGFR1","FGF2","TLR2","TLR4","HAPLN1","BMPR1B"],"other_free_text":[]},"mechanistic_narrative":"ASPN (asporin/PLAP-1) is a secreted small leucine-rich repeat proteoglycan that functions as a multi-ligand extracellular signaling modulator, regulating osteogenic, chondrogenic, adipogenic, and inflammatory pathways. It directly binds BMP-2 through its LRR5 motif to competitively block BMP-2–BMPR-IB engagement and downstream Smad signaling, thereby inhibiting mineralization and cytodifferentiation, with the D14 aspartic acid repeat polymorphism conferring enhanced BMP-2 binding and stronger signaling suppression [PMID:17522060, PMID:18407830, PMID:24453179]. ASPN also directly binds FGF-2 to promote FGF-2–FGFR1 complex formation and positively regulate FGF-2 signaling, and binds TLR2/TLR4 to suppress NF-κB/IκB kinase-dependent inflammatory cytokine production [PMID:26239644, PMID:26399972]. In vivo, ASPN-expressing periodontal ligament cells serve as progenitors that differentiate into osteoblasts and cementoblasts, and ASPN loss leads to altered collagen fibril architecture, enlarged periodontal ligament space, and accelerated bone loss in periodontitis [PMID:36245218, PMID:37958972]."},"prefetch_data":{"uniprot":{"accession":"Q9BXN1","full_name":"Asporin","aliases":["Periodontal ligament-associated protein 1","PLAP-1"],"length_aa":380,"mass_kda":43.4,"function":"Negatively regulates periodontal ligament (PDL) differentiation and mineralization to ensure that the PDL is not ossified and to maintain homeostasis of the tooth-supporting system. Inhibits BMP2-induced cytodifferentiation of PDL cells by preventing its binding to BMPR1B/BMP type-1B receptor, resulting in inhibition of BMP-dependent activation of SMAD proteins (By similarity). Critical regulator of TGF-beta in articular cartilage and plays an essential role in cartilage homeostasis and osteoarthritis (OA) pathogenesis. Negatively regulates chondrogenesis in the articular cartilage by blocking the TGF-beta/receptor interaction on the cell surface and inhibiting the canonical TGF-beta/Smad signal. Binds calcium and plays a role in osteoblast-driven collagen biomineralization activity","subcellular_location":"Secreted, extracellular space, extracellular matrix","url":"https://www.uniprot.org/uniprotkb/Q9BXN1/entry"},"depmap":{"release":"DepMap","has_data":false,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/ASPN"},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/ASPN","total_profiled":1310},"omim":[{"mim_id":"608135","title":"ASPORIN; ASPN","url":"https://www.omim.org/entry/608135"},{"mim_id":"607850","title":"OSTEOARTHRITIS SUSCEPTIBILITY 3; OS3","url":"https://www.omim.org/entry/607850"},{"mim_id":"603932","title":"INTERVERTEBRAL DISC DISEASE; IDD","url":"https://www.omim.org/entry/603932"},{"mim_id":"165720","title":"OSTEOARTHRITIS SUSCEPTIBILITY 1; OS1","url":"https://www.omim.org/entry/165720"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Uncertain","locations":[{"location":"Nucleoplasm","reliability":"Uncertain"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"blood vessel","ntpm":129.3},{"tissue":"heart muscle","ntpm":89.2},{"tissue":"smooth muscle","ntpm":103.1}],"url":"https://www.proteinatlas.org/search/ASPN"},"hgnc":{"alias_symbol":["FLJ20129","SLRR1C","PLAP-1"],"prev_symbol":[]},"alphafold":{"accession":"Q9BXN1","domains":[{"cath_id":"3.80.10.10","chopping":"77-160","consensus_level":"medium","plddt":96.4682,"start":77,"end":160},{"cath_id":"3.80.10.10","chopping":"184-380","consensus_level":"medium","plddt":95.2692,"start":184,"end":380}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9BXN1","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9BXN1-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9BXN1-F1-predicted_aligned_error_v6.png","plddt_mean":85.88},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=ASPN","jax_strain_url":"https://www.jax.org/strain/search?query=ASPN"},"sequence":{"accession":"Q9BXN1","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9BXN1.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9BXN1/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9BXN1"}},"corpus_meta":[{"pmid":"17522060","id":"PMC_17522060","title":"PLAP-1/asporin, a novel negative regulator of periodontal ligament mineralization.","date":"2007","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/17522060","citation_count":160,"is_preprint":false},{"pmid":"20712325","id":"PMC_20712325","title":"Analysis of isoaspartic Acid by selective proteolysis with Asp-N and electron transfer dissociation mass spectrometry.","date":"2010","source":"Analytical chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/20712325","citation_count":88,"is_preprint":false},{"pmid":"22514560","id":"PMC_22514560","title":"ASPN and GJB2 Are Implicated in the Mechanisms of Invasion of Ductal Breast Carcinomas.","date":"2012","source":"Journal of Cancer","url":"https://pubmed.ncbi.nlm.nih.gov/22514560","citation_count":70,"is_preprint":false},{"pmid":"21329514","id":"PMC_21329514","title":"Association of the D repeat polymorphism in the ASPN gene with developmental dysplasia of the hip: a case-control study in Han Chinese.","date":"2011","source":"Arthritis research & therapy","url":"https://pubmed.ncbi.nlm.nih.gov/21329514","citation_count":60,"is_preprint":false},{"pmid":"17517696","id":"PMC_17517696","title":"Meta-analysis of association between the ASPN D-repeat and osteoarthritis.","date":"2007","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/17517696","citation_count":58,"is_preprint":false},{"pmid":"18407830","id":"PMC_18407830","title":"PLAP-1/asporin inhibits activation of BMP receptor via its leucine-rich repeat motif.","date":"2008","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/18407830","citation_count":49,"is_preprint":false},{"pmid":"22367347","id":"PMC_22367347","title":"miR-21 and miR-101 regulate PLAP-1 expression in periodontal ligament cells.","date":"2012","source":"Molecular medicine 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Positively Regulates FGF-2 Activity.","date":"2015","source":"Journal of dental research","url":"https://pubmed.ncbi.nlm.nih.gov/26239644","citation_count":23,"is_preprint":false},{"pmid":"31665048","id":"PMC_31665048","title":"Identifying the role of ASPN and COMP genes in knee osteoarthritis development.","date":"2019","source":"Journal of orthopaedic surgery and research","url":"https://pubmed.ncbi.nlm.nih.gov/31665048","citation_count":22,"is_preprint":false},{"pmid":"36245218","id":"PMC_36245218","title":"Plap-1 lineage tracing and single-cell transcriptomics reveal cellular dynamics in the periodontal ligament.","date":"2022","source":"Development (Cambridge, England)","url":"https://pubmed.ncbi.nlm.nih.gov/36245218","citation_count":22,"is_preprint":false},{"pmid":"16311710","id":"PMC_16311710","title":"High-resolution SNP map of ASPN, a susceptibility gene for osteoarthritis.","date":"2005","source":"Journal of human 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biophysics","url":"https://pubmed.ncbi.nlm.nih.gov/25030405","citation_count":10,"is_preprint":false},{"pmid":"23733110","id":"PMC_23733110","title":"The D-repeat polymorphism in the ASPN gene and primary knee osteoarthritis in a Mexican mestizo population: a case-control study.","date":"2013","source":"Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association","url":"https://pubmed.ncbi.nlm.nih.gov/23733110","citation_count":9,"is_preprint":false},{"pmid":"16879361","id":"PMC_16879361","title":"Porcine OGN and ASPN: mapping, polymorphisms and use for quantitative trait loci identification for growth and carcass traits in a Meishan x Piétrain intercross.","date":"2006","source":"Animal genetics","url":"https://pubmed.ncbi.nlm.nih.gov/16879361","citation_count":9,"is_preprint":false},{"pmid":"36394011","id":"PMC_36394011","title":"Identification of nanoparticle-mediated siRNA-ASPN as a key gene target in the treatment of keloids.","date":"2022","source":"Frontiers in bioengineering and biotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/36394011","citation_count":8,"is_preprint":false},{"pmid":"37427673","id":"PMC_37427673","title":"ASPN Synergizes with HAPLN1 to Inhibit the Osteogenic Differentiation of Bone Marrow Mesenchymal Stromal Cells and Extracellular Matrix Mineralization of Osteoblasts.","date":"2023","source":"Orthopaedic surgery","url":"https://pubmed.ncbi.nlm.nih.gov/37427673","citation_count":8,"is_preprint":false},{"pmid":"26031659","id":"PMC_26031659","title":"Overexpression of PLAP-1 in bone marrow stromal cells inhibits the rat critical-size skull defect repair.","date":"2015","source":"Journal of molecular histology","url":"https://pubmed.ncbi.nlm.nih.gov/26031659","citation_count":7,"is_preprint":false},{"pmid":"21146486","id":"PMC_21146486","title":"Selective isolation of N-blocked peptide by combining AspN digestion, transamination, and tosylhydrazine glass treatment.","date":"2010","source":"Analytical biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/21146486","citation_count":7,"is_preprint":false},{"pmid":"37958972","id":"PMC_37958972","title":"Mice Lacking PLAP-1/Asporin Show Alteration of Periodontal Ligament Structures and Acceleration of Bone Loss in Periodontitis.","date":"2023","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/37958972","citation_count":4,"is_preprint":false},{"pmid":"35138637","id":"PMC_35138637","title":"Reciprocal role of PLAP-1 in HIF-1α-mediated responses to hypoxia.","date":"2022","source":"Journal of periodontal research","url":"https://pubmed.ncbi.nlm.nih.gov/35138637","citation_count":3,"is_preprint":false},{"pmid":"39301785","id":"PMC_39301785","title":"Investigating MATN3 and ASPN as novel drivers of gastric cancer progression via EMT pathways.","date":"2024","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/39301785","citation_count":3,"is_preprint":false},{"pmid":"26016288","id":"PMC_26016288","title":"[D-repeat polymorphism in the ASPN gene in knee osteoarthritis in females in Torreón, Coahuila. Case-control study].","date":"2014","source":"Acta ortopedica mexicana","url":"https://pubmed.ncbi.nlm.nih.gov/26016288","citation_count":3,"is_preprint":false},{"pmid":"39928346","id":"PMC_39928346","title":"Defect Imide Double Antiperovskites AE5AsPn(NH)2 (AE=Ca, Sr; Pn=Sb, Bi) as Potential Solar Cell Absorber Materials.","date":"2025","source":"Angewandte Chemie (International ed. in English)","url":"https://pubmed.ncbi.nlm.nih.gov/39928346","citation_count":3,"is_preprint":false},{"pmid":"21431266","id":"PMC_21431266","title":"[Construction and confirmation of a recombinant eukaryotic expression plasmid pBABE-hygro-PLAP-1].","date":"2010","source":"Shanghai kou qiang yi xue = Shanghai journal of stomatology","url":"https://pubmed.ncbi.nlm.nih.gov/21431266","citation_count":3,"is_preprint":false},{"pmid":"39662603","id":"PMC_39662603","title":"Single-cell transcriptomic analysis and luteolin treatment reveal three adipogenic genes, including Aspn, Htra1 and Efemp1.","date":"2024","source":"Biochimica et biophysica acta. Molecular and cell biology of lipids","url":"https://pubmed.ncbi.nlm.nih.gov/39662603","citation_count":1,"is_preprint":false},{"pmid":"41689014","id":"PMC_41689014","title":"Engineered Cas9 exosome vesicles as a novel gene editing tool for targeted ASPN editing in osteoarthritis.","date":"2026","source":"Journal of nanobiotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/41689014","citation_count":0,"is_preprint":false},{"pmid":"41258306","id":"PMC_41258306","title":"Exploring ASPN as a pan-cancer biomarker with a focus on gastric cancer.","date":"2025","source":"Discover oncology","url":"https://pubmed.ncbi.nlm.nih.gov/41258306","citation_count":0,"is_preprint":false},{"pmid":"41723544","id":"PMC_41723544","title":"Epithelial cell-derived exosomes carry NamiRNA-143-5p and promote ASPN expression in fibroblasts to induce Helicobacter pylori infected gastritis progression.","date":"2026","source":"Gut pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/41723544","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2024.11.21.624638","title":"Unravelling the molecular activation of the reparative cardiac fibroblasts after myocardial infarction","date":"2024-11-21","source":"bioRxiv","url":"https://doi.org/10.1101/2024.11.21.624638","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":22842,"output_tokens":3711,"usd":0.062095},"stage2":{"model":"claude-opus-4-6","input_tokens":7201,"output_tokens":2750,"usd":0.157133},"total_usd":0.219228,"stage1_batch_id":"msgbatch_01TqNM6p6FsoMBT2jzQTwKBr","stage2_batch_id":"msgbatch_01Ya473eco8sTHbvRymQaU8o","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2007,\n      \"finding\": \"PLAP-1/asporin directly binds BMP-2 (shown by co-immunoprecipitation) and negatively regulates BMP-2-induced mineralization and cytodifferentiation of periodontal ligament cells; overexpression inhibits and knockdown enhances BMP-2-induced differentiation.\",\n      \"method\": \"Co-immunoprecipitation, overexpression, RNA interference, in vitro mineralization assay, immunohistochemistry\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP plus functional KD/OE with defined cellular phenotype, replicated in subsequent studies\",\n      \"pmids\": [\"17522060\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"PLAP-1/asporin inhibits BMP-2 signaling by competitively preventing BMP-2 from binding BMPR-IB, thereby blocking Smad activation; the LRR5 motif within the leucine-rich repeat region is required for BMP-2 interaction, and a 26-amino acid LRR5 peptide is sufficient to inhibit BMP-2 activity.\",\n      \"method\": \"Recombinant protein competition binding assay, site-directed mutagenesis of LRR5, Smad phosphorylation western blot, peptide inhibition assay\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro reconstituted competition assay plus mutagenesis identifying active LRR5 domain\",\n      \"pmids\": [\"18407830\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"PLAP-1/asporin directly binds FGF-2 (shown by binding assay) and promotes formation of the FGF-2–FGFR1 complex, positively regulating FGF-2 signaling; Plap-1 knockout MEFs show defective FGF-2 responses rescued by Plap-1 re-introduction.\",\n      \"method\": \"Binding assay, co-immunoprecipitation, Plap-1 knockout MEFs, Plap-1 gene transfection rescue, immunocytochemistry colocalization\",\n      \"journal\": \"Journal of dental research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — direct binding assay, knockout rescue, and colocalization with multiple orthogonal methods\",\n      \"pmids\": [\"26239644\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"PLAP-1/asporin directly binds TLR2 and TLR4 (shown by immunoprecipitation), suppresses NF-κB activation, reduces IκB kinase α degradation induced by TLR4, and inhibits TLR2/4-induced proinflammatory cytokine expression in periodontal ligament cells and macrophages.\",\n      \"method\": \"Immunoprecipitation, NF-κB luciferase reporter assay, recombinant protein treatment, overexpression, western blot (IκBα degradation)\",\n      \"journal\": \"Journal of dental research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — Co-IP binding, functional NF-κB reporter, and IκBα mechanistic readout with multiple cell types\",\n      \"pmids\": [\"26399972\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"The D14 allele of the aspartic acid repeat polymorphism of PLAP-1/asporin shows stronger binding affinity to BMP-2 (by co-immunoprecipitation) and more potently suppresses BMP-2-induced differentiation and signal transduction in PDL cells compared with the D13 allele.\",\n      \"method\": \"Co-immunoprecipitation, BMP-2 signaling western blot, luciferase reporter assay, alkaline phosphatase and alizarin red staining\",\n      \"journal\": \"Journal of dental research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods linking polymorphism to differential binding affinity and functional output\",\n      \"pmids\": [\"24453179\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"miR-21 and miR-101 directly target the PLAP-1/asporin 3′UTR to repress its expression during osteogenic differentiation of periodontal ligament cells.\",\n      \"method\": \"Dual luciferase reporter assay, qRT-PCR, bioinformatic target prediction\",\n      \"journal\": \"Molecular medicine reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — luciferase reporter validates direct targeting; single lab\",\n      \"pmids\": [\"22367347\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"1,25(OH)2D3 transcriptionally suppresses PLAP-1 expression in human periodontal ligament stem cells through a vitamin D receptor element (VDRE) identified in the PLAP-1 promoter, validated by ChIP assay and reporter gene assay.\",\n      \"method\": \"ChIP assay, luciferase reporter assay, qRT-PCR, western blot\",\n      \"journal\": \"International immunopharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ChIP and reporter assay confirm VDR-VDRE interaction; single lab\",\n      \"pmids\": [\"31837573\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"PLAP-1/asporin expression is upregulated in periodontal ligament cells under hypoxia via HIF-1α activation; reciprocally, recombinant PLAP-1 suppresses hypoxia-response element (HRE) reporter activity and HIF-1α nuclear accumulation in a dose-dependent manner, indicating a negative feedback loop.\",\n      \"method\": \"HRE-luciferase reporter assay, western blot (HIF-1α nuclear accumulation), recombinant protein treatment, PLAP-1 gene transfection, qRT-PCR\",\n      \"journal\": \"Journal of periodontal research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — reporter assay plus protein-level mechanistic readout; single lab\",\n      \"pmids\": [\"35138637\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"PLAP-1/asporin enhances adipogenesis; Plap-1 knockout mice and Plap-1-knockdown 3T3-L1 cells show reduced lipid accumulation, while recombinant PLAP-1 enhances lipid accumulation, demonstrating a direct role in adipocyte differentiation.\",\n      \"method\": \"Plap-1 knockout mice, siRNA knockdown in 3T3-L1 cells, recombinant protein treatment, lipid accumulation assay, ECM gene expression profiling\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function (KO and KD) plus gain-of-function (recombinant protein) with defined cellular phenotype\",\n      \"pmids\": [\"33654143\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"PLAP-1/asporin regulates periodontal ligament collagen fibril diameter and ECM composition; PLAP-1 knockout mice display enlarged PDL space, increased collagen diameter (TEM), upregulated ECM proteins (Col3, BGN, DCN), reduced tooth extraction force, and accelerated alveolar bone loss in ligature-induced periodontitis with more osteoclasts.\",\n      \"method\": \"PLAP-1 knockout mice, micro-CT, histology (HE, picrosirius red), TEM of collagen fibrils, fluorescence immunostaining, tooth extraction force measurement, ligature periodontitis model\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — KO with multiple orthogonal structural and functional readouts; single lab\",\n      \"pmids\": [\"37958972\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"ASPN interacts with HAPLN1 (shown by protein interaction analysis and binding assay in BMSCs), and their combined knockdown synergistically promotes osteogenic differentiation of BMSCs and ECM mineralization of osteoblasts while reducing osteoclastogenesis.\",\n      \"method\": \"Co-immunoprecipitation/protein interaction assay, siRNA knockdown (individual and combined), ALP/osteogenic marker western blot, ECM mineralization assay, osteoclastogenesis assay in OVX mouse model\",\n      \"journal\": \"Orthopaedic surgery\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — protein interaction plus functional KD; single lab\",\n      \"pmids\": [\"37427673\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"PLAP-1/asporin lineage tracing in knock-in mice confirmed that Plap-1-positive periodontal ligament cells differentiate into osteoblasts and cementoblasts, and contribute to periodontal tissue regeneration after injury.\",\n      \"method\": \"CreERT2 knock-in lineage tracing, single-cell RNA sequencing, RNA velocity analysis, GFP reporter\",\n      \"journal\": \"Development (Cambridge, England)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — genetic lineage tracing with single-cell atlas; defines cell differentiation hierarchy\",\n      \"pmids\": [\"36245218\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"miR-4303 directly targets ASPN mRNA (validated by dual-luciferase reporter assay), and miR-4303 overexpression reduces ASPN protein levels, rescuing LPS-induced chondrocyte inflammation, cell cycle arrest, and apoptosis.\",\n      \"method\": \"Dual-luciferase reporter assay, western blot, qRT-PCR, flow cytometry, ELISA\",\n      \"journal\": \"Journal of orthopaedic surgery and research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — luciferase reporter validates direct targeting; single lab with multiple functional readouts\",\n      \"pmids\": [\"34663368\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"MATN3 directly interacts with ASPN (confirmed by protein-protein interaction and co-expression analyses), and ASPN overexpression amplifies MATN3-driven gastric cancer cell proliferation, migration, invasion, and EMT activation both in vitro and in vivo.\",\n      \"method\": \"Protein-protein interaction analysis, co-expression analysis, overexpression, siRNA knockdown, proliferation/migration/invasion assays, mouse xenograft model\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — interaction supported by bioinformatics + functional assays; mechanistic detail limited\",\n      \"pmids\": [\"39301785\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"lncRNA DCST1-AS1 binds the miR-21 precursor (not mature miR-21) to suppress miR-21 levels, thereby de-repressing PLAP-1/asporin expression and inhibiting periodontal ligament cell proliferation.\",\n      \"method\": \"qPCR, western blot, transfection experiments, CCK-8 proliferation assay, bioinformatics prediction\",\n      \"journal\": \"Journal of periodontal research\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — indirect mechanism inferred from expression rescue experiments; no direct binding validated biochemically\",\n      \"pmids\": [\"33533513\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"Exosomal miR-143-5p from H. pylori-infected epithelial cells functions as a nuclear activating miRNA (NamiRNA) that binds the ASPN super-enhancer region, increases H3K27ac enrichment, and transcriptionally upregulates ASPN in fibroblasts, promoting downstream pro-inflammatory cytokine (IL-4, IL-6, TGF-β) expression.\",\n      \"method\": \"microRNA sequencing, immunofluorescence, co-culture assay, ChIP (H3K27ac), immunohistochemistry, antagomir in vivo\",\n      \"journal\": \"Gut pathogens\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ChIP validates super-enhancer binding; in vivo antagomir confirms pathway; single lab\",\n      \"pmids\": [\"41723544\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ASPN (asporin/PLAP-1) is a secreted small leucine-rich repeat proteoglycan that acts as a multi-functional extracellular regulator: it directly binds BMP-2 via its LRR5 motif to competitively block BMPR-IB engagement and downstream Smad signaling (inhibiting osteogenic/chondrogenic differentiation), directly binds FGF-2 to promote FGF-2–FGFR1 complex formation (positively regulating FGF-2 signaling), directly binds TLR2 and TLR4 to suppress NF-κB/IκB kinase signaling and inflammatory cytokine production, modulates HIF-1α activity through a negative feedback loop under hypoxia, promotes adipogenesis, and regulates periodontal ligament collagen fibril architecture; its activity is subject to post-transcriptional regulation by miR-21 and miR-101, and transcriptional regulation by VDR and HIF-1α.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"ASPN (asporin/PLAP-1) is a secreted small leucine-rich repeat proteoglycan that functions as a multi-ligand extracellular signaling modulator, regulating osteogenic, chondrogenic, adipogenic, and inflammatory pathways. It directly binds BMP-2 through its LRR5 motif to competitively block BMP-2–BMPR-IB engagement and downstream Smad signaling, thereby inhibiting mineralization and cytodifferentiation, with the D14 aspartic acid repeat polymorphism conferring enhanced BMP-2 binding and stronger signaling suppression [PMID:17522060, PMID:18407830, PMID:24453179]. ASPN also directly binds FGF-2 to promote FGF-2–FGFR1 complex formation and positively regulate FGF-2 signaling, and binds TLR2/TLR4 to suppress NF-κB/IκB kinase-dependent inflammatory cytokine production [PMID:26239644, PMID:26399972]. In vivo, ASPN-expressing periodontal ligament cells serve as progenitors that differentiate into osteoblasts and cementoblasts, and ASPN loss leads to altered collagen fibril architecture, enlarged periodontal ligament space, and accelerated bone loss in periodontitis [PMID:36245218, PMID:37958972].\",\n  \"teleology\": [\n    {\n      \"year\": 2007,\n      \"claim\": \"Establishing that asporin is not merely an extracellular matrix structural component but an active signaling modulator: direct binding to BMP-2 and functional inhibition of BMP-2-induced mineralization in periodontal ligament cells revealed a previously unknown antagonistic role for this SLRP.\",\n      \"evidence\": \"Co-immunoprecipitation of ASPN–BMP-2, overexpression/knockdown in PDL cells with mineralization readout\",\n      \"pmids\": [\"17522060\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Binding domain on ASPN not yet mapped\", \"Mechanism of inhibition (competitive vs. allosteric) unknown\", \"In vivo relevance not tested\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Resolving the mechanism of BMP-2 antagonism: ASPN competitively prevents BMP-2 from engaging BMPR-IB through its LRR5 motif, and a 26-amino-acid LRR5 peptide is sufficient to block BMP-2 signaling, pinpointing the minimal inhibitory domain.\",\n      \"evidence\": \"Reconstituted competition binding assay with recombinant proteins, LRR5 mutagenesis, Smad phosphorylation western blot, peptide inhibition\",\n      \"pmids\": [\"18407830\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of LRR5–BMP-2 interaction not determined\", \"Whether other BMP family members are similarly antagonized is untested\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Identifying a post-transcriptional regulatory layer: miR-21 and miR-101 directly target the ASPN 3′UTR to repress its expression during osteogenic differentiation, suggesting that ASPN levels are actively tuned to permit differentiation.\",\n      \"evidence\": \"Dual-luciferase reporter assay validating direct 3′UTR targeting in PDL cells\",\n      \"pmids\": [\"22367347\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Endogenous stoichiometric relevance of miR-mediated repression not quantified\", \"Single lab without independent replication\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Linking a natural polymorphism to differential signaling output: the D14 aspartic acid repeat allele shows stronger BMP-2 binding and greater suppression of BMP-2-driven differentiation than D13, providing a molecular basis for disease-association studies of this polymorphism.\",\n      \"evidence\": \"Co-immunoprecipitation comparing D13 vs D14 allelic variants, BMP-2 signaling reporter and differentiation assays\",\n      \"pmids\": [\"24453179\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural explanation for how additional aspartate residues increase affinity is absent\", \"Population-level functional impact not directly measured\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Demonstrating that ASPN is a dual-function signaling modulator with opposing effects on different pathways: it positively regulates FGF-2 signaling by promoting FGF-2–FGFR1 complex formation, and negatively regulates TLR2/TLR4-NF-κB inflammatory signaling by direct receptor binding.\",\n      \"evidence\": \"Direct binding assays, Plap-1 KO MEFs with rescue (FGF-2), immunoprecipitation of ASPN–TLR2/TLR4, NF-κB reporter and IκBα degradation readouts\",\n      \"pmids\": [\"26239644\", \"26399972\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Domains on ASPN responsible for FGF-2 and TLR binding not mapped\", \"Whether FGF-2 and TLR ligand binding are mutually exclusive is unknown\", \"In vivo validation of anti-inflammatory function not performed\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Uncovering transcriptional regulation of ASPN: vitamin D receptor directly binds a VDRE in the ASPN promoter and suppresses transcription, establishing a hormonal input controlling ASPN expression in periodontal tissues.\",\n      \"evidence\": \"ChIP assay confirming VDR occupancy at ASPN promoter, luciferase reporter in human PDL stem cells\",\n      \"pmids\": [\"31837573\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether VDR regulation extends to non-periodontal tissues is untested\", \"Single lab\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Extending ASPN function beyond mineralized tissue: ASPN positively regulates adipogenesis, as demonstrated by reduced lipid accumulation in knockout mice and knockdown adipocytes and enhanced accumulation with recombinant protein.\",\n      \"evidence\": \"Plap-1 KO mice, siRNA in 3T3-L1, recombinant ASPN gain-of-function, lipid accumulation assays\",\n      \"pmids\": [\"33654143\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Signaling pathway mediating pro-adipogenic effect not identified\", \"Whether BMP-2 antagonism contributes to adipogenic shift is untested\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Defining ASPN-expressing cells as a stem/progenitor population: lineage tracing showed that Plap-1-positive periodontal ligament cells differentiate into osteoblasts and cementoblasts and contribute to tissue regeneration after injury, establishing ASPN as a marker of a multipotent progenitor.\",\n      \"evidence\": \"CreERT2 knock-in lineage tracing, scRNA-seq, RNA velocity in mice\",\n      \"pmids\": [\"36245218\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether ASPN protein is functionally required for progenitor self-renewal or merely marks the population is unclear\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Revealing a hypoxia–ASPN negative feedback loop: HIF-1α induces ASPN expression under hypoxia, while ASPN reciprocally suppresses HIF-1α nuclear accumulation and HRE transcriptional activity, suggesting homeostatic control of hypoxic responses.\",\n      \"evidence\": \"HRE-luciferase reporter, western blot for nuclear HIF-1α, recombinant ASPN dose-response in PDL cells\",\n      \"pmids\": [\"35138637\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular mechanism by which extracellular ASPN reduces nuclear HIF-1α is unknown\", \"Single lab\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Establishing an in vivo structural role: ASPN knockout mice exhibit enlarged periodontal ligament space, increased collagen fibril diameter, altered ECM composition, reduced tooth anchorage, and accelerated bone loss with increased osteoclastogenesis in periodontitis.\",\n      \"evidence\": \"Plap-1 KO mice, micro-CT, TEM of collagen fibrils, ligature periodontitis model, tooth extraction force measurement\",\n      \"pmids\": [\"37958972\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether collagen fibril phenotype is cell-autonomous or secondary to altered signaling is unresolved\", \"Molecular mechanism of osteoclastogenesis promotion not defined\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include: the structural basis of ASPN interactions with its multiple ligands (BMP-2, FGF-2, TLR2/4), whether distinct binding events are mutually exclusive or cooperative, the signaling pathway through which ASPN promotes adipogenesis, and the mechanism by which an extracellular protein suppresses nuclear HIF-1α accumulation.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No crystal structure or cryo-EM model of ASPN or its complexes\", \"No systematic mapping of which LRR domains mediate each interaction\", \"Mechanism of HIF-1α suppression by an extracellular protein uncharacterized\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 1, 2, 3, 4]},\n      {\"term_id\": \"GO:0048018\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [0, 2, 3, 9]},\n      {\"term_id\": \"GO:0031012\", \"supporting_discovery_ids\": [9]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0162582\", \"supporting_discovery_ids\": [0, 1, 2, 3, 4]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [3]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [0, 1, 11]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"BMP2\", \"FGFR1\", \"FGF2\", \"TLR2\", \"TLR4\", \"HAPLN1\", \"BMPR1B\"],\n    \"other_free_text\": []\n  }\n}\n```"}