MicroRNA-210-5p Alleviates Cardiac Fibrosis via Targeting Transforming Growth Factor-beta Type I Receptor in Rats on High Salt Diet

Abstract Background: The aim of the present study was to explore whether high salt diet (HSD) caused cardiac fibrosis regardless of blood pressure in rats, and to determine the effects of microRNA (miR)-210-5p on sodium chloride (NaCl)-induced fibrosis in neonatal rat cardiac fibroblasts (NRCFs) and its target. Methods: The rats received 8% HSD in vivo, and NRCFs were treated with NaCl in vitro. Results: The levels of collagen I, alpha-smooth muscle actin (α-SMA) and transforming growth factor-beta (TGF-β) were increased in the heart of hypertension (HTN), hypertension-prone (HP) and hypertension-resistant (HR) rats on HSD. Middle and high doses (50 mM and 100 mM) of NaCl increased the levels of collagen I, α-SMA and TGF-β in NRCFs. The expression level of miR-210-5p was reduced in NaCl-treated NRCFs by miR high-throughput sequencing. The NaCl-induced increases of collagen I, α-SMA and TGF-β were inhibited by miR-210-5p agomiR, and further enhanced by miR-210-5p antagomiR. Bioinformatics analysis and luciferase reporter assays demonstrated that TGF-β type I receptor (TGFβRI) was a direct target gene of miR-210-5p. These results indicated that HSD resulted in cardiac fibrosis regardless of blood pressure. Conclusion: The upregulation of miR-210-5p could attenuate NRCF fibrosis via targeting TGFβRI. Thus, upregulating miR-210-5p to inhibit TGF-β signaling pathway might be a strategy for the treatment of cardiac fibrosis.