Methamphetamine Exposure Induces Neuronal Programmed Necrosis by Permeabilizing Mitochondria via the RIPK1-RIPK3-MLKL Axis.

Methamphetamine (Meth), a psychostimulant drug of the amphetamine type, is widely abused and highly neurotoxic. Meth exposure leads to neuronal necroptosis, and the mitochondrial dysfunction may be involved. However, the underlying mechanisms remain poorly understood. Here, we found that Meth significantly elicited the formation of the RIPK1-RIPK3-MLKL necrosome complex. Intriguingly, the activated MLKL (p-MLKL) translocated to the mitochondrial membrane and displayed pore-forming activity, manifesting as the penetration of MLKL in the cell membranes of the mitochondria, which caused decreased mitochondrial membrane potential, ATP generation, and mitochondrial DNA (mtDNA) and increased mitochondrial ROS (mtROS) generation, which finalized neuronal necroptosis. Notably, MLKL activation and translocation seem to depend on the RIPK1-RIPK3 axis since these adverse effects can be substantially ameliorated by disruption of the necrosome complex formation by the necroptotic inhibitor 1 (Nec-1), which also markedly impeded the MLKL mitochondrial membrane translocation. Finally, to delineate the effects of pore formation-associated ROS generation, specific blockage of mtROS retarded the Meth-induced neuronal necroptosis. In conclusion, our study reveals for the first time that MLKL mitochondrial membrane translocation may be involved in Meth-induced neuronal necroptosis. Therefore, impeding MLKL translocation might provide a novel therapeutic strategy for Meth-induced neurotoxicity.