Ptbp2 Alleviates Neuroinflammation and Blood–brain Barrier Disruption via Modulating Microglial Polarization in Ischemic Stroke

Damage following ischemic stroke is worsened by microglial activation and subsequent neuroinflammation. Polypyrimidine tract binding protein 2 (Ptbp2) can influence the chemotaxis and repolarization of cancer-related macrophages; however, its specific role in microglial polarization and the underlying mechanisms are not yet fully understood. This study aimed to elucidate the neuroprotective mechanisms of Ptbp2 and examine its effects on microglial activation, neuroinflammation, and glucose metabolism following cerebral ischemia. Mice model of ischemic stroke was developed using temporary middle cerebral artery occlusion (tMCAO). Adeno-associated viruses were used for overexpression and knockdown in C57 mice, and microglial polarization, blood-brain barrier (BBB) integrity, and glycolytic parameters in the peri-infarct cortex were evaluated. RNA sequencing (RNA-seq) was performed on mouse brain tissues. To investigate the underlying mechanisms, the mouse brain microvascular endothelial cell line bEnd.3 and BV2 microglial cell line were used. The protective effect of Ptbp2 on BBB integrity following stroke was evaluated by targeted overexpression and knockdown. We found that Ptbp2 overexpression reduced microglia-mediated neuroinflammation and BBB damage while inhibiting pathological glycolysis, according to findings from both in vitro and in vivo studies. Additionally, Ptbp2 level was significantly downregulated in patients with stroke compared to controls, and was inversely correlated with the severity of neural impairment. Our study unveils novel immunomodulatory mechanisms in stroke and highlights Ptbp2 and its regulatory network as potential therapeutic targets for stroke.