Cardiac fibroblast-derived CCN1 aggravates diabetic cardiomyopathy through ITGAV-ITGB1/integrin αvβ1-mediated autophagy inhibition.

deletion ameliorated cardiac dysfunction and restored autophagic activity. We further identified ITGAV-ITGB1/integrin αvβ1 as the receptor mediating CCN1 signaling in cardiomyocytes. Molecular dynamics simulations and co-immunoprecipitation experiments confirmed that CCN1 engaged ITGAV-ITGB1/integrin αvβ1 through its cysteine-knot-containing (CT) domain. Mechanistically, this interaction activated the downstream PTK2/FAK-MTOR signaling pathway, leading to inhibition of cardiomyocyte autophagy. Together, these findings reveal a previously unrecognized fibroblast-cardiomyocyte signaling axis in which fibroblast-derived CCN1 drives DCM progression by suppressing autophagy through ITGAV-ITGB1/integrin αvβ1-dependent signaling. This work provides mechanistic insight into the pathogenesis of DCM and identifies CCN1 as a potential therapeutic target for mitigating disease onset and progression.