GSTpi is a Phase II metabolic enzyme which is originally considered as an important facilitator of cellular detoxification. Here, we found that GSTpi stabilized VE-cadherin in endothelial cell membrane through inhibiting VE-cadherin phosphorylation and VE-cadherin/catenin complex dissociation, and consequently maintained endothelial barrier function. Our findings demonstrated a novel mechanism that GSTpi inhibited VE-cadherin phosphorylation through suppressing the activation of Src/VE-cadherin pathway. Mass spectrometry analysis and molecular docking showed that GSTpi enhanced Src S-glutathionylation at Cys185, Cys245, and Cys400 of Src. More important, we found that GSTpi promoted S-glutathionylation of Src was essential for GSTpi to inhibit Src phosphorylation and activation. Furthermore, in vivo experiments indicated that AAV-GSTpi exerted the protective effect on pulmonary vessel permeability in the animal model of acute lung injury. This study revealed a novel regulatory effect of GSTpi on vascular endothelial barrier function and the importance of S-glutathionylation of Src induced by GSTpi in the activation of Src/VE-cadherin pathway.

GSTpi是II期代谢酶，最初被认为是细胞排毒的重要促进剂。在这里，我们发现，GSTpi通过抑制VE-钙粘蛋白的磷酸化和VE-钙粘蛋白/连环蛋白复合物的解离，稳定了内皮细胞膜中的VE-钙粘蛋白，从而维持了内皮屏障功能。我们的发现证明了GSTpi通过抑制Src / VE-钙粘蛋白途径的激活而抑制VE-钙粘蛋白磷酸化的新机制。质谱分析和分子对接表明，GSTpi增强了Src的Cys185，Cys245和Cys400的Src S-谷胱甘肽化。更重要的是，我们发现GSTpi促进Src的S-谷胱甘肽酰化对于GSTpi抑制Src磷酸化和激活至关重要。此外，体内实验表明，AAV-GSTpi在急性肺损伤动物模型中对肺血管通透性具有保护作用。这项研究揭示了GSTpi对血管内皮屏障功能的新型调节作用，以及GSTpi诱导Src的Src谷胱甘肽酰化在Src / VE-钙粘蛋白途径活化中的重要性。