Chen Yang, Li Guangbi, Bhat Owais M, Li Xiang, Zhang Yang, Li Pin-Lan
School of Chinese Materia Medica, Guangzhou University of Chinese Medicine, Guangzhou, China.
Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States.
Front Physiol. 2022 Jul 6;13:910339. doi: 10.3389/fphys.2022.910339. eCollection 2022.
Recent studies have indicated that instant cell membrane resealing (ICMR) controls the activation of NOD-like receptor pyrin domain containing 3 (Nlrp3) inflammasomes in endothelial cells, thereby initiating and promoting vascular inflammation. It remains unknown whether this impaired ICMR occurs under diabetic condition or hyperglycemia contributing to endothelial dysfunction leading to vascular inflammation, a hallmark of diabetic vascular injury. The present study aims to examine whether ICMR occurs during in control and diabetic mice and to explore related molecular mechanisms associated with acid sphingomyelinase (ASM)-mediated ceramide production. Using confocal microscopy, we demonstrated that mouse aortic endothelial cells (MAECs) exposed to high glucose levels exhibited much more retarded ICMR after laser-induced membrane injury, compared to that in control cells. The high glucose-induced impairment of membrane resealing in MAECs was prevented when these cells were pretreated with sphingomyelin or C24-ceramide. Mechanistically, high glucose treatment decreased association of membrane ceramide with annexin A5, an essential element of membrane repair machinery. Consistently, the association of ceramide with annexin A5 was significantly reduced in the coronary arterial endothelium of mice with streptozotocin-induced diabetes mellitus compared to that in non-diabetic control mice. Moreover, a marked reduction of the association of ceramide with annexin A5 was observed in coronary arterial endothelium of ASM knockout mice regardless of their diabetic status. Lastly, high glucose treatment or ASM gene deletion substantially impaired ICMR in coronary arterial endothelium of mice receiving membrane puncturing agents. Collectively, our data suggest that ceramide-mediated ICMR in vascular endothelial cells is impaired during diabetes mellitus due to dissociation of ceramide with annexin A5 and ASM play a critical role in this ICMR.
最近的研究表明，即时细胞膜重封（ICMR）可控制内皮细胞中含NOD样受体吡喃结构域3（Nlrp3）炎性小体的激活，从而引发并促进血管炎症。目前尚不清楚这种受损的ICMR是否发生在糖尿病状态或高血糖情况下，而高血糖会导致内皮功能障碍，进而引发血管炎症，这是糖尿病血管损伤的一个标志。本研究旨在检测ICMR是否在对照小鼠和糖尿病小鼠中发生，并探索与酸性鞘磷脂酶（ASM）介导的神经酰胺生成相关的分子机制。利用共聚焦显微镜，我们证明，与对照细胞相比，暴露于高糖水平的小鼠主动脉内皮细胞（MAECs）在激光诱导的膜损伤后，ICMR明显延迟。当用鞘磷脂或C24-神经酰胺预处理这些细胞时，可防止高糖诱导的MAECs膜重封受损。从机制上讲，高糖处理减少了膜神经酰胺与膜修复机制的关键成分膜联蛋白A5的结合。同样，与非糖尿病对照小鼠相比，链脲佐菌素诱导的糖尿病小鼠冠状动脉内皮中神经酰胺与膜联蛋白A5的结合显著减少。此外，无论糖尿病状态如何，在ASM基因敲除小鼠的冠状动脉内皮中均观察到神经酰胺与膜联蛋白A5的结合明显减少。最后，高糖处理或ASM基因缺失显著损害了接受膜穿刺剂的小鼠冠状动脉内皮中的ICMR。总的来说，我们的数据表明，由于神经酰胺与膜联蛋白A5解离，糖尿病期间血管内皮细胞中神经酰胺介导的ICMR受损，而ASM在这种ICMR中起关键作用。
