Relationship between β-arrestin1-GAPDH interaction and the DADLE-mediated protection of brain microvascular endothelial cells from hypoxia-ischemic/reperfusion injury

Cerebral stroke has a high mortality rate primarily driven by the pathophysiological processes of ischemia-reperfusion (I/R) injury. [D-Ala², D-Leu⁵]-enkephalin (DADLE), the agonist of δ receptor, has raised interest as a tissue-protective agent for its ability to improve I/R injury, although its specific mechanism remains unclear. In this study, middle cerebral artery occlusion/reperfusion (MCAO/R) was induced in rats, while oxygen-glucose deprivation/reoxygenation (OGD/R) was applied to brain microvascular endothelial cells (BMECs). The effect of DADLE effect on Autophagy regulation was assessed, and the interaction between β-arrestin and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was identified. DADLE elevated Autophagy levels in both in vivo and in vitro I/R models and improve BMEC viability under I/R conditions. After I/R injury, β-arrestin-GAPDH interaction tended to increase; however, DADLE treatment released GAPDH that was bound to β-arrestins. Simultaneously, DADLE reversed GAPDH activity caused by I/R injury. Quantitative Real-Time PCR detection revealed that, BMECs dominantly express a subtype of β-arrestin, β-arrestin1, which is necessary for DADLE-dependent cellular Autophagy level and GAPDH activity enhancement. Therefore, this study provides evidence that DADLE may serve as a potential anti-ischemic stroke therapeutic agent.