Abstract 230: Cartilage Intermediate Layer Protein-1 Attenuates Pressure Overload-induced Cardiac Fibrosis by Targeting Transforming Growth Factor-β1

Abstract

Background: Cartilage intermediate layer protein-1 (CILP-1), a monomeric extracellular matrix glycoprotein expressed mainly in the middle zones of articular cartilage, interacts directly with transforming growth factor-β1 (TGF-β1). Recent studies showed that CILP-1 was upregulated in the heart tissue following cardiac ischemia reperfusion injury. However, the role of CILP-1 in pathological cardiac remodeling is poorly defined. Aims: To explore the effect of CILP-1 on myocardial interstitial fibrosis and reveal the possible molecular mechanism. Methods and Results: We found that CILP-1 was mainly expressed in mouse cardiac fibroblasts (CFs) by using western blot analysis and immunofluorescence. Myocardial expression of CILP-1 was upregulated in mice subjected to transverse aortic constriction (TAC) for 2, 4, and 8 weeks. AAV-9-mediated delivery of CILP-1 into mice increased the binding of CILP-1 with TGF-β1, attenuated interstitial fibrosis, and improved cardiac function. In cultured adult mouse CFs, CILP-1 overexpression inhibited myofibroblast differentiation and expression of profibrotic molecules induced by TGF-β1. Furthermore, CILP-1 attenuated TGF-β1-induced Smad3 phosphorylation and nuclear translocation. Conclusions: CILP-1 alleviates pressure overload-induced cardiac fibrosis and dysfunction. CILP-1 exerts its anti-fibrotic effect through targeting TGF-β1 signaling. This study will offer a new therapeutic strategy for preventing and treating myocardial interstitial remodeling.