Downregulated lncRNA-MIAT confers protection against erectile dysfunction by downregulating lipoprotein lipase via activation of miR-328a-5p in diabetic rats.

Erectile dysfunction (ED) is a common comorbidity in males with diabetes. In this study, we aimed to investigate how lncRNA-MIAT affects ED in diabetes and the involved mechanism. Microarray analysis was performed to screen ED-related differentially expressed genes, regulatory microRNA (miR) and long noncoding RNA (lncRNA). Highly expressed lipoprotein lipase (LPL) was identified, and subsequently miR-328a-5p and lncRNA-MIAT were determined. Diabetes was induced by streptozotocin in rats, and diabetic rats with ED were selected. Vascular smooth muscle cells (VSMCs) and vascular endothelial cells (VECs) were cocultured. The siRNA against lncRNA-MIAT, miR-328a-5p mimic and overexpression vector of LPL were transfected to investigate the specific effects of miR-328a-5p, lncRNA-MIAT and LPL on ED in diabetes. The expression of LPL, lncRNA-MIAT and miR-328a-5p in the serum of diabetic patients was measured. Increased LPL and lncRNA-MIAT and reduced miR-328a-5p were observed in diabetic patients. In addition, ED led to upregulated LPL and lncRNA-MIAT and downregulated miR-328a-5p in serum of diabetic patients and VSMCs of diabetic rats, especially in those with ED. LncRNA-MIAT directly regulated miR-328a-5p, which directly targeted LPL. LncRNA-MIAT upregulated LPL by acting as a ceRNA of miR-328a-5p. Silencing of lncRNA-MIAT and LPL or miR-328a-5p overexpression reduced VEC apoptosis and increased cell proliferation. In addition, an increased intracavernosal pressure (ICP)/mean arterial pressure (MAP) ratio was noted in the corpus cavernosum of rats and inhibited VEC injury. Taken together, our data demonstrated that depleted lncRNA-MIAT suppressed LPL by increasing miR-328a-5p, thereby inhibiting VEC injury to attenuate ED in diabetic rats.