Velvet antler peptide prevents pressure overload-induced cardiac fibrosis via transforming growth factor (TGF)-β1 pathway inhibition

Abstract

Velvet antlers (VAs) are commonly used in traditional Chinese medicine and invigorant and contain many functional components for health promotion. The velvet antler peptide sVAP32 is one of active components in VAs; based on structural study, the sVAP32 interacts with TGF-β1 receptors and disrupts the TGF-β1 pathway. We hypothesized that sVAP32 prevents cardiac fibrosis from pressure overload by blocking TGF-β1 signaling. Sprague–Dawley rats underwent transverse aortic constriction (TAC) or a sham operation. After one month, rats received either sVAP32 (15mg/kg/day) or vehicle for an additional one month. TAC surgery induced significant cardiac dysfunction, fibroblast activation and fibrosis; these effects were improved by treatment with sVAP32. In the heart tissue, TAC remarkably increased the expression of TGF-β1 and connective tissue growth factor (CTGF), reactive oxygen species levels, and the phosphorylation levels of Smad2/3 and extracellular signal-regulated kinases 1/2 (ERK1/2). SVAP32 inhibited the increases in reactive oxygen species levels, CTGF expression and the phosphorylation of Smad2/3 and ERK1/2, but not TGF-β1 expression. In cultured cardiac fibroblasts, angiotensin II (Ang II) had similar effects compared to TAC surgery, such as increases in α-SMA-positive cardiac fibroblasts and collagen synthesis. SVAP32 eliminated these effects by disrupting TGF-β1 binding to its receptors and blocking Ang II/TGF-β1 downstream signaling. These results demonstrated that sVAP32 has anti-fibrotic effects by blocking the TGF-β1 pathway in cardiac fibroblasts.