Indoxyl sulfate promotes the atherosclerosis through up-regulating the miR-34a expression in endothelial cells and vascular smooth muscle cells in vitro.

Atherosclerosis (AS) is one of the most common cardiovascular events in patients with chronic renal insufficiency (CRI). During the development of CRI, uremic toxins, including indoxyl sulfate (IS), are pivotal risk factors for AS. However, the underlying mechanism between AS and IS has not been fully elucidated. The present study was designed to test our hypothesis that IS promotes the AS by regulating viability, proliferation, migration and apoptosis of endothelial cells and vascular smooth muscle cells. In this present study, our date showed that IS inhibited the cell viability of human umbilical vein endothelial cells (HUVECs) and human aortic vascular smooth muscle cells (HA-VSMCs) in a dose-dependent manner (P < .05). Moreover, IS inhibited the proliferation, migration and induced apoptosis of HUVECs and HA-VSMCs significantly (P < .05). However, inhibition of the miR-34a abolished these effects of IS in vitro, indicating that miR-34a is involved in the development of AS induced by IS. In addition, the luciferase reporter gene assay showed that up-regulating of miR-34a inhibited the Notch1 transcriptional activity remarkably (P < .05). The expression of Notch1 decreased after IS treatment, while miR-34a inhibitor attenuated this effect. Moreover, the expression of miR-34a-related proteins Wnt-1, Jag1, E2F1 and SIRT1 decreased, while the expression of p53 increased in HUVECs and HA-VSMCs after IS treatment. Consistently, blockage of miR-34a abolished the remarkable effects on protein expressions induced by IS. Taken together, this study showed that IS can inhibit the proliferation, migration and promote apoptosis of HUVECs and HA-VSMCs through the Notch1 signal and miR-34a-related proteins by up-regulating miR-34a. These findings may provide new insights into the underlying mechanism of AS in CRI.