Solasonine alleviates high glucose-induced podocyte injury through increasing Nrf2-medicated inhibition of NLRP3 activation.

The worldwide high prevalence of diabetic nephropathy is one of the common causes of renal failure in diabetic patients. Hyperglycemia-caused podocyte injury is considered as a major contributor to diabetic kidney disease, accompanied by a chronic inflammatory condition. Pyroptosis, a characterized inflammatory form of programmed cell death, is believed to be involved in the pathogenesis of diabetic nephropathy. Solasonine (SS) is a natural alkaloid and received attention as a potential anticancer agent. However, its protective effect against hyperglycemia-caused podocyte injury remains to be determined. Our study found that SS alleviates cell apoptosis, and reduces pyroptosis and oxidative damage in high glucose (HG)-treated MPC5 podocytes. Pro-inflammatory cytokines, including interleukin (IL)-1β and IL-18, and caspase-1 activity were markedly suppressed by SS in HG-treated MPC5 podocytes. SS also reduced HG-induced oxidative damage in MPC5 podocytes. Nrf2 expression was activated by SS in vitro under a HG condition. In addition, Nrf2 silencing attenuated the protective effect of SS against apoptosis, pro-inflammatory cytokines release, caspase-1 activity, and oxidative damage in MPC5 podocytes under a HG condition. Taken together, our findings revealed for the first time that SS alleviated high glucose-induced podocyte apoptosis, pyroptosis, and oxidative damage via regulating the Nrf2/NLRP3 signaling pathway. Our results indicate that SS has the potential as a therapeutic agent for podocyte injury in diabetic nephropathy.