Histone lactylation stimulated upregulation of PSMD14 alleviates neuron PANoptosis through deubiquitinating PKM2 to activate PINK1-mediated mitophagy after traumatic brain injury

Alleviating the multiple types of programmed neuronal death caused by mechanical injury has been an impetus for designing neuro-therapeutical approaches after traumatic brain injury (TBI). The aim of this study was to elucidate the potential role of PSMD14 (proteasome 26S subunit, non-ATPase 14) in neuron death and the specific mechanism through which it improves prognosis of TBI patients. Here, we identified differential expression of the PSMD14 protein between the controlled cortical impact (CCI) and sham mouse groups by LC-MS proteomic analysis and found that PSMD14 was significantly upregulated in neurons after brain injury by qPCR and western blot. PSMD14 suppressed stretch-induced neuron PANoptosis and improved motor ability and learning performance after CCI in vivo. Mechanistically, PSMD14 improved PINK1 phosphorylation levels at Thr257 and activated PINK1-mediated mitophagy by deubiquitinating PKM/PKM2 (pyruvate kinase M1/2) to maintain PKM protein stability. PSMD14-induced mitophagy promoted mitochondrial homeostasis to reduced ROS production, and ultimately inhibited the neuron PANoptosis. The upregulation of neuronal PSMD14 after TBI was due to the increase of histone lactation modification level and lactate treatment alleviated neuron PANoptosis via increasing PSMD14 expression. Our findings suggest that PSMD14 could be a potential therapeutic approach for improving the prognosis of TBI patients.<b>Abbreviations:</b> CCI: controlled cortical impact; CQ: chloroquine; DUBs: deubiquitinating enzymes; H3K18la: H3 lysine 18 lactylation; IB: immunoblot; IHC: immunohistochemistry; IP: immunoprecipitation; MLKL: mixed lineage kinase domain like pseudokinase; PI3K: phosphoinositide 3-kinase; PINK1: PTEN induced kinase 1; PKM/PKM2: pyruvate kinase M1/2; PSMD14: proteasome 26S subunit, non-ATPase 14; ROS: reactive oxygen species; RIPK1: receptor interacting serine/threonine kinase 1; RIPK3: receptor interacting serine/threonine kinase 3; TBI: traumatic brain injury.