microRNA Expression Profiles in Myocardium of High-Fat Diet-Induced Obesity Rat.

A high-fat diet (HFD) can lead to cardiac dysfunction, hypertrophy, and fibrosis. This study aimed to explore microRNA expression profiles in the myocardium of HFD-induced obesity rat. Wistar rats were randomly divided into two groups, and fed with normal chow diet (NCD) or HFD for 20 weeks. Cardiac function was evaluated by echocardiography. Left ventricular myocardium was harvested to assess the extent of myocardial morphology alteration. MicroRNA expression was analyzed using Agilent miRNA microarray and quantitative real-time PCR (qRT-PCR) was used to validate the microarray data. The mirdbV6 database was used to forecast the miRNA target genes. The role of microRNAs in palmitate-induced cardiac hypertrophy and fibrosis in primary neonatal rat cardiomyocytes was evaluated by loss- and gain-of-function experiments. Significant changes in cardiac function, hypertrophy, fibrosis, and apoptosis were found in HFD rats as compared with NCD rats. miR-141-3p and miR-144-3p were also significantly upregulated in the myocardium of HFD-induced obesity rat. A series of genes involved in essential biological processes, including anatomical structure development and metabolic process, was targeted by these two miRNAs. These target genes were also implicated in signaling pathways involved in the PI3K-Akt signaling pathway, Wnt signaling pathway, autophagy, and protein processing in the endoplasmic reticulum. Inhibition of miR-141 or overexpression of miR-144 attenuated palmitate-induced cardiac hypertrophy and fibrosis. In contrast, overexpression of miR-141 or inhibition of miR-144 aggravated palmitate-induced cardiac hypertrophy and fibrosis. This study identifies that miR-141 and miR-144 are candidate miRNAs associated with the development of HFD-induced cardiac dysfunction and structure alteration.