Knockdown of SESN2 Exacerbates Cerebral Ischemia-Reperfusion Injury Through Enhancing Glycolysis via the mTOR/HIF-1α Pathway

Reprogramming of glycometabolism plays a crucial role in the pathogenesis of cerebral ischemia-reperfusion injury (CIRI). Sestrin2 (SESN2), a sensor upstream of the mTORC1, is closely related to glycometabolism. However, the effect and mechanism of SESN2 in CIRI are unclear. The goal of this research was to explore the effect of SESN2 on CIRI and its potential mechanisms related to glycometabolism.

Knockdown of SESN2 in MCAO mice increased the expression of the p-mTOR/HIF-1α pathway, which increased glycolysis and lactate levels and, in turn, affected IS injury.

Lentiviral vectors carrying SESN2 shRNA (Lenti-SESN2) or negative NC virus (Lenti-GFP) or rapamycin (mTOR inhibitor) were employed in the oxygen-glucose deprivation/reoxygenation (OGD/R) model and in the middle cerebral artery occlusion (MCAO) mice. In all, 3 days after I/R, neurological deficit scores and infarct size were assessed. The glycolysis and SESN2 levels were determined by RT-qPCR, Western blots, and immunofluorescence staining. Lactate levels were detected by a lactate assay kit, and the expression of the p-mTOR/HIF-1α signaling pathway was measured by immunofluorescence staining and protein blotting.

Local SESN2 deficiency in brain tissue increased the infarct size and reduced neurological scores 3 days after I/R. Moreover, the results showed that local SESN2 deficiency in brain tissue increased the expression of glycolysis-related proteins, including HK2, PFKM, PKM1, PKM2, and GLUT1. The lactate assay kit showed that local SESN2 deficiency in brain tissue increased lactate levels. In addition, local SESN2 deficiency in brain tissue improved the expression of the p-mTOR/HIF-1α pathway. However, rapamycin (RAP) treatment reversed these results, suggesting that SESN2 may influence IS injury by regulating glycometabolism via p-mTOR/HIF-1α pathway regulation. SESN2 knockdown in BV2 cells improved the glycolysis levels and the expression of the mTOR/HIF-1α pathway in the OGD/R model in vitro, but RAP treatment can also reverse these results. Conclusions: Knockdown of SESN2 in MCAO mice increased the expression of the p-mTOR/HIF-1α pathway, which increased glycolysis and lactate levels and, in turn, affected IS injury.