Integrin αVβ3-mediated focal adhesion signaling promotes fibroblast activation during renal fibrosis.

Abstract

Renal fibrosis is a progressive pathological process underlying chronic kidney disease (CKD), characterized by persistent fibroblast activation and excessive extracellular matrix accumulation. Although integrin-dependent focal adhesion signaling has been implicated in tissue fibrosis, its role in renal fibroblast activation remains incompletely understood. In this study, publicly available single-cell and bulk transcriptomic datasets were integrated to characterize fibroblast-associated signaling alterations in fibrotic kidneys. Experimental validation was subsequently performed in a 5/6 nephrectomy rat model and TGF-β1-stimulated NRK-49F cells. Bioinformatic analyses revealed enrichment of extracellular matrix organization, focal adhesion, and cytoskeleton-related pathways in activated fibroblasts. Increased integrin αVβ3 expression and enhanced focal adhesion signaling were further confirmed in fibrotic renal tissues. Pharmacological inhibition of integrin αVβ3 with cyclo-RGDfK attenuated fibroblast adhesion, migration, and extracellular matrix production, accompanied by reduced FAK phosphorylation and RhoA expression. Furthermore, inhibition of FAK with PF-573228 impaired focal adhesion remodeling, disrupted F-actin stress fiber organization, and reduced fibroblast activation and extracellular matrix production. Pharmacological inhibition of ROCK with Y-27632 reduced MYPT1 phosphorylation, accompanied by impaired F-actin stress fiber organization and decreased fibroblast activation, supporting a functional role of ROCK signaling in focal adhesion remodeling and fibroblast activation. Collectively, these findings indicate that integrin αVβ3-associated FAK and RhoA/ROCK signaling contribute to focal adhesion remodeling and fibroblast activation during renal fibrosis, suggesting that this signaling network may represent a potential therapeutic target for renal fibrosis.