Fibroblast Iron Metabolic Reprogramming Links Chronic Inflammation to Extracellular Matrix Remodeling and Pathological Ossification

Fibroblast Iron Metabolic Reprogramming Links Chronic Inflammation to Extracellular Matrix Remodeling and Pathological Ossification | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Fibroblast Iron Metabolic Reprogramming Links Chronic Inflammation to Extracellular Matrix Remodeling and Pathological Ossification Jing Liu, Dachun Zhuo, Qingmei Liu, Yulong Tang, Lilu Zu, Ying Wang, and 11 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9232122/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Joints and their associated ligamentous structures constitute a dynamic interface for immune–stromal interactions, and chronic inflammatory joint diseases are marked by a paradoxical coexistence of persistent inflammation and progressive structural remodeling, including fibrosis and ectopic bone formation. Using radiographic axial spondyloarthritis (r-axSpA) as a disease model, we identify fibroblasts as key tissue-level organizers of inflammation-driven joint remodeling through dysregulated iron metabolism. Integrating single-cell transcriptomic analyses of patient tissues with genetic and functional studies in multiple experimental models, we show that among diverse stromal and immune populations within inflamed joints, ligament and tendon fibroblasts uniquely accumulate iron and engage extracellular matrix (ECM) remodeling programs. Mechanistically, inflammatory signaling—most prominently tumor necrosis factor α (TNFα)—reprograms fibroblast iron handling by sustaining expression of the iron transporter SLC39A14, thereby enabling persistent iron influx. Iron-loaded fibroblasts drive excessive ECM deposition, reshape stromal–immune crosstalk, and generate a tissue microenvironment permissive for pathological ossification. In vivo, fibroblast-specific disruption of this pathway attenuates iron accumulation, fibrotic remodeling, and aberrant bone formation, while ECM deposited by iron- and inflammation-reprogrammed fibroblasts is sufficient to instruct osteogenic differentiation of mesenchymal progenitors. Together, these findings identify fibroblast-mediated iron handling as a tissue-level control mechanism that links chronic inflammation to joint remodeling and ossification, providing a generalizable framework for structural pathology in inflammatory diseases. Biological sciences/Cell biology Health sciences/Diseases/Rheumatic diseases r-axSpA Fibroblast SLC39A14 Iron metabolism Osteophyte formation Full Text Additional Declarations There is no duality of interest Supplementary Files SupplenmentaryTableS1andS2.docx Supplenmentary Table S1, Supplenmentary Table S2 SupplenmentaryTableS3andS4.xlsx Supplenmentary Table S3, Supplenmentary Table S4 SupplenmentaryFigure.pdf Supplenmentary Figure 1, Supplenmentary Figure 2,Supplenmentary Figure 3, Supplenmentary Figure 4,Supplenmentary Figure 5, Supplenmentary Figure 6,Supplenmentary Figure 7 Uncroppedimagesforblots.pdf Uncropped images for blots Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9232122","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":619103621,"identity":"0ece351a-0db3-45ac-8b8c-daea0d48bca0","order_by":0,"name":"Jing 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Ossification","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"r-axSpA, Fibroblast, SLC39A14, Iron metabolism, Osteophyte 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Using radiographic axial spondyloarthritis (r-axSpA) as a disease model, we identify fibroblasts as key tissue-level organizers of inflammation-driven joint remodeling through dysregulated iron metabolism. Integrating single-cell transcriptomic analyses of patient tissues with genetic and functional studies in multiple experimental models, we show that among diverse stromal and immune populations within inflamed joints, ligament and tendon fibroblasts uniquely accumulate iron and engage extracellular matrix (ECM) remodeling programs. Mechanistically, inflammatory signaling—most prominently tumor necrosis factor α (TNFα)—reprograms fibroblast iron handling by sustaining expression of the iron transporter SLC39A14, thereby enabling persistent iron influx. Iron-loaded fibroblasts drive excessive ECM deposition, reshape stromal–immune crosstalk, and generate a tissue microenvironment permissive for pathological ossification. In vivo, fibroblast-specific disruption of this pathway attenuates iron accumulation, fibrotic remodeling, and aberrant bone formation, while ECM deposited by iron- and inflammation-reprogrammed fibroblasts is sufficient to instruct osteogenic differentiation of mesenchymal progenitors. 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