TRPM2 enhances ischemic excitotoxicity by associating with PKC

N-methyl-D-aspartate receptor (NMDAR)-mediated glutamate excitotoxicity significantly contributes to ischemic neuronal death and post-recanalization infarction expansion. Despite tremendous efforts, targeting NMDARs has proven unsuccessful in clinical trials for mitigating brain injury. Here, we show the discovery of an interaction motif for transient receptor potential melastatin 2 (TRPM2) and protein kinase Cy (PKCy) association and demonstrate that TRPM2-PKCy uncoupling is an effective therapeutic strategy for attenuating NMDAR-mediated excitotoxicity in ischemic stroke. We demonstrate that the TRPM2-PKCy interaction allows TRPM2-mediated Ca2+ influx to promote PKCy activation, which subsequently enhances TRPM2induced potentiation of extrasynaptic NMDAR (esNMDAR) activity. By identifying the PKCy binding motif on TRPM2 (M2PBM), which directly associates with the C2 domain of PKCy, an interfering peptide (TATM2PBM) is developed to disrupt TRPM2-PKCy interaction without compromising PKCy function. M2PBM deletion or TRPM2-PKCy dissociation abolishes both TRPM2-PKCy and TRPM2-esNMDAR couplings, resulting in reduced excitotoxic neuronal death and attenuated ischemic brain injury.