Extracellular vesicle-mediated miR135a-5p transfer in hypertensive rat contributes to vascular smooth muscle cell proliferation via targeting FNDC5.

Background Extracellular vesicles (EVs) from vascular adventitial fibroblasts (AFs) contribute to the proliferation of vascular smooth muscle cells (VSMCs) and vascular remodeling in spontaneously hypertensive rat (SHR). This study shows the crucial roles of EVs-mediated miR135a-5p transfer in VSMC proliferation and the underlying mechanisms in hypertension. Methods AFs and VSMCs were obtained from the aorta of Wistar-Kyoto rat (WKY) and SHR. EVs were isolated from the culture of AFs with ultracentrifugation method. Results MiR135a-5p level in SHR-EVs was significantly increased. MiR135a-5p inhibitor prevented the SHR-EVs-induced VSMC proliferation. Fibronectin type III domain containing 5 (FNDC5) was a target gene of miR135a-5p. FNDC5 level was lower in VSMCs of SHR. MiR135a-5p inhibitor not only increased FNDC5 expression, but reversed the SHR-EVs-induced FNDC5 downregulation in VSMCs of SHR. MiR135a-5p mimic inhibited FNDC5 expression, but failed to promote the SHR-EVs-induced FNDC5 downregulation in VSMCs of SHR. Exogenous FNDC5 prevented the SHR-EVs-induced VSMC proliferation of both WKY and SHR. Knockdown of miR135a-5p in fibroblasts completely prevented the upregulation of miR135a-5p in the EVs. The SHR-EVs from the miR135a-5p knockdown-treated fibroblasts lost their roles in inhibiting FNDC5 expression and promoting proliferation in VSMCs of both WKY and SHR. Conclusions Increased miR135a-5p in the SHR-EVs promoted VSMC proliferation of WKY and SHR via inhibiting FNDC5 expression. MiR135a-5p and FNDC5 are crucial targets for intervention of VSMC proliferation in hypertension.