Lactylation of GDF15 Regulates Angiogenesis in Ischemic Stroke via Activating PI3K/AKT/mTOR Pathway

Ischemic stroke (IS) is a major health burden. The role of growth differentiation factor 15 (GDF15) in IS has been scarcely reported, and this study aimed to explore its expression and underlying mechanisms. The middle cerebral artery occlusion (MCAO) mice model and oxygen-glucose deprivation (OGD) mice brain microvascular endothelial cells (MBMVECs) models were established. Brain infarction size and neurological score were calculated following MCAO surgery. Cell counting kit-8, Transwell migration, and wound healing assays were performed to evaluate the cell viability, migration, and invasion of MBMVECs. Immunoprecipitation and Western blot were used to analyze the lactylation level of GDF15. The involvement of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway was confirmed using the specific inhibitor LY294002. GDF15 was upregulated in IS patients and in MCAO/OGD models. Modulating GDF15 expression affected cell viability, migration, wound healing, and angiogenesis in MBMVECs. In animal study, GDF15 overexpression alleviated MCAO-induced brain injury and promoted angiogenesis. Mechanistically, GDF15 was lactylated at lysine 142 (K142) in OGD-treated MBMVECs, and this modification enhanced GDF15 protein stability and its pro-angiogenic function. Mutation of the K142 site (K142R) abolished these effects. Furthermore, GDF15 activated the PI3K/AKT/mTOR signaling pathway, and pharmacological inhibition of PI3K with LY294002 reversed the protective effects of GDF15. GDF15 plays a crucial role in IS by promoting angiogenesis and protecting against ischemic injury. This function is regulated by K142 lactylation and mediated through the PI3K/AKT/mTOR pathway. Our findings highlight GDF15 and its lactylation as potential therapeutic targets for ischemic stroke.