MicroRNA-7 targets Nod-like receptor protein 3 inflammasome to modulate neuroinflammation in the pathogenesis of Parkinson’s disease

In this study, we showed that NLRP3 inflammasomes were activated in the serum of PD patients and the midbrain of PD model mice. We further clarified that α-syn activated the NLRP3 inflammasome through microglial endocytosis and subsequent lysosomal cathepsin B release. Deficiency of caspase-1, an important component of NLRP3 inflammasome, significantly inhibited α-syn-induced microglia activation and interleukin-1β production, which in turn alleviated the reduction of mesencephalic dopaminergic neurons treated by microglia medium. Specifically, we demonstrated for the first time that Nlrp3 is a target gene of microRNA-7 (miR-7). Transfection of miR-7 inhibited microglial NLRP3 inflammasome activation whereas anti-miR-7 aggravated inflammasome activation in vitro. Notably, stereotactical injection of miR-7 mimics into mouse striatum attenuated dopaminergic neuron degeneration accompanied by the amelioration of microglial activation in MPTP-induced PD model mice.