WWP2 Overexpression Represses NLRP3 Inflammasome Activation in Cerebral Ischemia/Reperfusion Injury Through the Degradation of MAVS.

NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inflammasome plays a pivotal role in the progression of cerebral ischemia/reperfusion injury (CI/RI). We aimed to investigate the implication of WW domain-containing protein 2 (WWP2), an E3 ubiquitin ligase, in CI/RI and its mechanism. Microglia were subjected to oxygen-glucose deprivation/reoxygenation, and mice were subjected to middle cerebral artery occlusion (MCAO) for modeling. WWP2 was reduced in the brain tissues of mice with MCAO/R. WWP2 overexpression in microglia inhibited the NLRP3 inflammasome activation to alleviate MCAO/R-induced injury and microglia-induced neurotoxicity. WWP2 inhibited the mitochondrial translocation of NLRP3 by degrading mitochondrial antiviral-signaling protein (MAVS) to block its interaction with NLRP3, and MAVS overexpression in microglia promoted the NLRP3 activation to exacerbate MCAO/R and neurotoxicity. The nuclear export of TAR DNA-binding protein 43 (TDP-43) in MCAO/R promoted the WWP2 degradation via the (UG)n element of the 3'UTR of WWP2. TDP-43 overexpression also impaired the blockade of NLRP3 activation and exacerbated neurotoxicity in the presence of WWP2. Overall, our investigations demonstrate that nuclear export of TDP-43 in microglia activates NLRP3 inflammasome and exacerbates CI/RI by blocking MAVS degradation through (UG)n element-mediated instability of WWP2.