Biology subjects

Iozzo, R. V.

Publications and source records attributed to Iozzo, R. V..

3 recordsLinked to original sources

bioRxiv2026

Decorin-mediated Extracellular Matrix Stabilization Maintains Cartilage Integrity During Aging

Aging is a primary risk factor for osteoarthritis (OA), yet the mechanisms that preserve extracellular matrix integrity in long-lived connective tissues remain poorly defined. The function of articular cartilage depends on maintaining extracellular matrix integrity over a lifetime of mechanical use. Here we identify failure of matrix stabilization as an initiating mechanism of age-associated OA. Cartilage-specific deletion of decorin in mature mice disrupted the superficial collagen II fibrillar network, reduced aggrecan retention, and impaired poroelastic fluid pressurization by 9 months of age, preceding substantial transcriptional changes in resident chondrocytes. With advancing age, these matrix defects culminated in cartilage erosion, fibrotic remodeling, and spontaneous OA by 18 months. Mechanistically, decorin attenuated force-induced collagen II fibril realignment and reinforced the superficial fibrillar network, preserving matrix architecture under sustained physiological loading. These findings establish decorin-mediated extracellular matrix stabilization as a critical determinant of cartilage longevity and support a matrix-first model of age-associated degeneration.

biophysics↗

bioRxiv2025

Decorin promotes nascent proteoglycan retention in cartilage matrix by strengthening collagen II-aggrecan integration

Cartilage extracellular matrix (ECM), a hydrated collagen II-aggrecan composite, undergoes dynamic turnover during both normal homeostasis and disease-associated remodeling. This study elucidates a crucial role for decorin in promoting the retention and stability of nascent aggrecan within this matrix. By applying bio-orthogonal click-labeling, we demonstrate that loss of decorin accelerates the release of nascent aggrecan under both physiological and inflammatory conditions, without affecting its preferred localization to the pericellular matrix. Conversely, supplementation with exogenous decorin mitigates inflammation-induced loss of nascent aggrecan, supporting its potential as a therapeutic target. At the molecular level, decorin exhibits strong binding affinity for aggrecan, and enhances aggrecan-aggrecan and aggrecan-collagen II interactions, reinforcing its direct role in integrating cartilage matrix constituents. Also, by binding to collagen II, decorin stiffens the collagen II fibril network, thereby strengthening the confinement effect that limits the diffusive loss of entrapped aggrecan. Notably, decorin does not alter chondrocyte transcriptomic profiles in vivo, emphasizing its primary role in maintaining matrix integrity through biophysical mechanisms rather than cell signaling. Together, these findings provide a mechanistic foundation for developing decorin-based biomaterials or gene therapies aimed at preserving or regenerating the cartilage matrix for improved outcomes in osteoarthritis.

biophysics↗

bioRxiv2018

Autophagy regulates hyaluronan synthase 2 levels in vascular endothelial cells

Hyaluronan is emerging as a key player regulating wound repair, inflammation, and angiogenesis. Of the three hyaluronan synthases (HAS1-3), HAS2 is the main driver of tumorigenicity by enhancing hyaluronan deposition. We discovered that HAS2 was degraded in vascular endothelial cells via autophagy, a catabolic process evoked by endorepellin and endostatin, two angiostatic and pro-autophagic effectors, and by Torin 1, a specific mTOR inhibitor. Protracted autophagy increased co-localization of HAS2 with three core components of the autophagosome, LC3, p62, and ATG9A, and binding of HAS2 to ATG9A. Importantly, autophagic induction led to an exclusive and marked suppression of secreted hyaluronan with no significant effects on either heparan or chondroitin sulfate levels. Thus, we have unveiled autophagy as a key catabolic mechanism regulating the production of hyaluronan in endothelial cells. Moreover, our study provides a biological link between autophagy and angiogenesis that could lead to potential targets for tumor neovascularization.\n\nSummaryHyaluronan is pro-angiogenic and pro-tumorigenic. We report a novel mechanism through which three autophagic inducers[-]endorepellin, endostatin, and Torin 1[-]regulate the levels of hyaluronan synthase-2. Protracted autophagy results in suppression of extracellular hyaluronan, thereby implicating autophagy in the regulation hyaluronan production.

cell biology↗