Abstract TP289: Protein Lactylation Regulation in Ischemic Stroke: Role of MeCP2 Lactylation in Repressing Apoptosis-Associated Gene Transcription

Abstract

Introduction: Lactate plays a vital role in various pathophysiological conditions including ischemic stroke. However, an unexplored dimension is the epigenetic modification originating from lactate, lysine lactylation (Kla), and its potential role in cerebral ischemia. Our research sought to elucidate the possible regulation of protein Kla in ischemic stroke, and its underlying mechanisms. Methods: Lactate concentration and pan-Kla levels were assessed in mice subjected to transient middle cerebral artery occlusion (MCAO) . Neurological functions and ischemic infarct volume were investigated through foot fault test and 2,3,5-triphenyltetrazolium chloride staining respectively. Proteomics analysis was used to examine protein Kla and key related proteins in the penumbra after one day of MCAO. Immunofluorescence, western blot, proximity ligation assay, and coimmunoprecipitation were performed to evaluate the cellular localization and modification sites of methyl-CpG-binding protein 2 (MeCP2). Joint CUT&Tag and RNA-sequencing analyses were utilized to identify MeCP2-Kla target genes. Results: We confirmed the accumulation of brain lactate and global protein Kla following cerebral ischemia. MeCP2 was identified as the central protein with Kla modification in ischemic stroke. Furthermore, the potentially beneficial role of neuronal MeCP2 lactylation in ischemic stroke was investigated. Our findings indicated that MeCP2 could protect against stroke-induced neuronal death through transcriptionally inactivating apoptosis-associated genes. It is showing various heterochromatin foci enrichment pattern in neuronal nuclei of different Kla level groups. In addition, it was found that MeCP2 Kla (Lys-210 and Lys-249) suppressed Pdcd4/Pla2g6 mRNA expression, thereby alleviating neurological deficit. Conclusions: MeCP2 lactylation exerts neuroprotection by transcriptionally regulates neuronal apoptosis, indicating it as a potential therapeutic target for ischemic stroke.