MicroRNA-155 Mediates Obesity-Induced Renal Inflammation and Dysfunction.

Chronic inflammation is a major contributor to obesity-related renal damage. Recent studies have demonstrated that microRNA (miR)-155 is closely associated with hyperglycemia-induced nephropathy, but whether renal miR-155 participates in the inflammatory response and development of obesity-related nephropathy is unknown. In present study, we investigated the pathophysiological role of renal miR-155 in palmitic acid (PA)-treated endothelial cell and high-fat-diet (HFD)-fed mouse models by specific miR-155 sponge. Mice fed with HFD exhibited higher levels of renal miR-155, which positively correlated with urine microalbumin and blood urea nitrogen. In vitro study, mouse renal vascular endothelial cells stimulated with PA also showed higher miR-155 levels, accompanied with increased inflammatory response. Suppression of renal miR-155 effectively attenuated HFD-induced renal structural damages and dysfunction. MiR-155 sponge treatment also significantly decreased NF-κB signaling and downstream gene expression in vitro and in vivo. The obesity-increased macrophage infiltration and lipotoxicity was decreased in mouse kidney after miR-155 sponge treatment. Mechanistically, miR-155 directly targeted 3'-UTR of SHIP1/INPP5D and suppressed its expression in vitro and in vivo, whereas silence of SHIP1/INPP5D abolished the renal protective benefits of miR-155 sponge in obese mice. Taken together, present findings for the first time provided evidence for the potential role of miR-155 in obesity-related nephropathy and clarified that SHIP1/NF-κB signaling was a potential molecular mechanism.