Zong Pengyu, Feng Jianlin, Li Cindy X, Jellison Evan R, Yue Zhichao, Miller Barbara, Yue Lixia
Department of Cell Biology, Calhoun Cardiology Center, University of Connecticut School of Medicine (UConn Health), 263 Farmington Ave, Farmington, CT 06030, USA.
Department of Neuroscience, University of Connecticut School of Medicine (UConn Health), 263 Farmington Ave, Farmington, CT 06030, USA.
Cardiovasc Res. 2024 Mar 13;120(2):188-202. doi: 10.1093/cvr/cvad126.
Damage of the blood-brain barrier (BBB) is a hallmark of brain injury during the early stages of ischemic stroke. The subsequent endothelial hyperpermeability drives the initial pathological changes and aggravates neuronal death. Transient receptor potential melastatin 2 (TRPM2) is a Ca2+-permeable nonselective cation channel activated by oxidative stress. However, whether TRPM2 is involved in BBB degradation during ischemic stroke remains unknown. We aimed to investigate the role of TRPM2 in BBB degradation during ischemic stroke and the underlying molecular mechanisms.
Specific deletion of Trpm2 in endothelial cells using Cdh5 Cre produces a potent protective effect against brain injury in mice subjected to middle cerebral artery occlusion (MCAO), which is characterized by reduced infarction size, mitigated plasma extravasation, suppressed immune cell invasion, and inhibited oxidative stress. In vitro experiments using cultured cerebral endothelial cells (CECs) demonstrated that either Trpm2 deletion or inhibition of TRPM2 activation attenuates oxidative stress, Ca2+ overload, and endothelial hyperpermeability induced by oxygen-glucose deprivation (OGD) and CD36 ligand thrombospondin-1 (TSP1). In transfected HEK293T cells, OGD and TSP1 activate TRPM2 in a CD36-dependent manner. Noticeably, in cultured CECs, deleting Trpm2 or inhibiting TRPM2 activation also suppresses the activation of CD36 and cellular dysfunction induced by OGD or TSP1.
In conclusion, our data reveal a novel molecular mechanism in which TRPM2 and CD36 promote the activation of each other, which exacerbates endothelial dysfunction during ischemic stroke. Our study suggests that TRPM2 in endothelial cells is a promising target for developing more effective and safer therapies for ischemic stroke.
血脑屏障（BBB）损伤是缺血性中风早期脑损伤的一个标志。随后的内皮细胞高通透性驱动了最初的病理变化并加重神经元死亡。瞬时受体电位香草酸亚型2（TRPM2）是一种由氧化应激激活的Ca2+通透性非选择性阳离子通道。然而，TRPM2是否参与缺血性中风期间的血脑屏障降解仍不清楚。我们旨在研究TRPM2在缺血性中风期间血脑屏障降解中的作用及其潜在的分子机制。
使用Cdh5 Cre在内皮细胞中特异性缺失Trpm2可对大脑中动脉闭塞（MCAO）小鼠的脑损伤产生强大的保护作用，其特征为梗死面积减小、血浆外渗减轻、免疫细胞浸润受到抑制以及氧化应激受到抑制。使用培养的脑内皮细胞（CEC）进行的体外实验表明，Trpm2缺失或TRPM2激活的抑制均可减轻由氧糖剥夺（OGD）和CD36配体血小板反应蛋白-1（TSP1）诱导的氧化应激、Ca2+过载和内皮细胞高通透性。在转染的HEK293T细胞中，OGD和TSP1以CD36依赖的方式激活TRPM2。值得注意的是，在培养的CEC中，删除Trpm2或抑制TRPM2激活也可抑制OGD或TSP1诱导的CD36激活和细胞功能障碍。
总之，我们的数据揭示了一种新的分子机制，即TRPM2和CD36相互促进激活，这在缺血性中风期间加剧了内皮功能障碍。我们的研究表明，内皮细胞中的TRPM2是开发更有效、更安全的缺血性中风治疗方法的一个有前景的靶点。
