Microrna363-5p targets thrombospondin3 to regulate pathological cardiac remodeling.

Cardiac remodeling is an end-stage manifestation of multiple cardiovascular diseases, and microRNAs are involved in a variety of posttranscriptional regulatory processes. miR-363-5p targeting Thrombospondin3 (THBS3) has been shown to play an important regulatory role in vascular endothelial cells, but the roles of these two in cardiac remodeling are unknown. Firstly, we established an in vivo model of cardiac remodeling by transverse aortic narrow (TAC), and then we stimulated a human cardiomyocyte cell line (AC16) and a human cardiac fibroblast cell line (HCF) using 1 μmol/L angiotensin II (Ang II) to establish an in vitro model of cardiac hypertrophy and an in vitro model of myocardial fibrosis, respectively. In all three of the above models, we found a significant decreasing trend of miR-363-5p, suggesting that it plays a key regulatory role in the occurrence and development of cardiac remodeling. Subsequently, overexpression of miR-363-5p significantly attenuated myocardial hypertrophy and myocardial fibrosis in vitro as evidenced by reduced the area of AC16, the cell viability of HCFs, the relative expression of the protein of fetal genes (ANP, BNP, β-MHC) and fibrosis marker (collagen I, collagen III, α-SMA), whereas inhibition of miR-363-5p expression showed the opposite trend. In addition, we also confirmed the targeted binding relationship between miR-363-5p and THBS3 by dual luciferase reporter gene assay, and the expression of THBS3 was directly inhibited by miR-363-5p. Moreover, overexpression of miR-363-5p with THBS3 simultaneously partially eliminated the delaying effect of miR-363-5p on myocardial hypertrophy and myocardial fibrosis in vitro. In conclusion, Overexpression of miR-363-5p attenuated the prohypertrophic and profibrotic effects of Ang II on AC16 and HCF by a mechanism related to the inhibition of THBS3 expression.