花生四烯酸CYP表氧化酶-EETs 信号系统-脑缺血神经血管单元整体保护的新靶点？

Past research and neurotherapeutic clinical trials have targeted the molecular mechanisms of neuronal cell death during stroke, but this approach has uniformly failed and the underlying mechanism remains unclear. Recent researches suggest that brain function and dysfunction are manifested at the level of cell-cell signaling between neuronal, glial and vascular(neurovascular unit) elements. It is increasingly evident that therapeutic approaches that target these various players in the ischemic cascade hold considerable promise for the treatment of acute ischemic stroke. Epoxyeicosatrienoic acids (EETs) are broadly cytoprotective signaling molecules, exerting vasodilator, angiogenic, anti-apoptotic, anti-inflammatory, and anti-oxidant effects in many tissues. The ability of several CNS cell types to produce and respond to EETs suggests that epoxyeicosanoid signaling is a key integrator of cell-cell communication in the CNS and may be the potential therapeutic target for stroke. In this project, we will study the expression, function of cytochrome P450 (CYP) epoxygenases-EETs in the brain under ischemic conditions using Two-photon in vivo imaging, patch clamp, and molecular biology methods. The involvement of CYP-EETs signaling in the damage and repair of neurovascular unit under ischemic conditions and the underlying mechanism will also be investigated. This would provide evidence showing the recognition of EETs' intimate involvement in CNS function in addition to their multi-cellular protective profile and inspired the development of therapeutic strategies targeting EETs against CNS diseases such as cerebral ischemia.

神经科学的最新进展提示，脑缺血神经损伤可归结为神经元、胶质细胞、血管（神经血管单元,NVU）间相互作用及通讯障碍。寻找对NVU多细胞成分具有保护作用的方法，从整体上促进其结构和信号重塑是潜在的发展方向。相关研究及前期工作基础发现内源性花生四烯酸CYP 表氧化酶-EETs在CNS广泛表达，具有抗氧化应激，抑制细胞凋亡，抗炎及促进血管新生的作用，是潜在的脑卒中多细胞整体保护靶点。但CYP-EETs信号在脑缺血神经血管单元结构与功能重塑中的作用及机制不明。本项目采用双光子成像、膜片钳、分子生物学等技术，利用离体及活体脑缺血模型，从分子、细胞、整体水平研究CYP表氧化酶-EETs在脑缺血神经血管单元组分的表达、功能、在神经血管单元信号耦合、损伤与重塑过程中的作用及机制。为进一步理解脑缺血的病理机制，开发新的治疗药物提供实验依据。

神经科学的最新进展提示，脑缺血神经损伤可归结为神经元、胶质细胞、血管（神经血管单元,NVU）间相互作用及通讯障碍。寻找对NVU多细胞成分具有保护作用的方法，从整体上促进其结构和信号重塑是潜在的发展方向。相关研究及前期工作基础发现内源性花生四烯酸CYP 表氧化酶-EETs在CNS广泛表达，具有抗氧化应激，抑制细胞凋亡，抗炎及促进血管新生的作用，是潜在的脑卒中多细胞整体保护靶点。但CYP-EETs信号在脑缺血神经血管单元结构与功能重塑中的作用及机制不明。本项目利用大鼠局灶脑缺血模型、小鼠双侧颈总动脉狭窄（BCAS）构建低灌注白质损伤模型、及脊髓损伤模型，从分子、细胞、整体水平研究CYP表氧化酶-EETs在脑缺血神经血管单元组分的表达、功能、在神经血管单元信号耦合、损伤与重塑过程中的作用及机制。结果发现CYP2C11和sEH在脑及脊髓神经血管单元各组分星形胶质细胞，神经元和血管内皮细胞均均广泛表达。外源性14,15-EET或者sEH抑制剂能显著抑制MCAO局灶脑缺血后大鼠脑内星形胶质细胞活化和胶质疤痕形成，抑制小胶质细胞活化及炎性反应，促进血管新生，减少神经元凋亡和梗死体积，最终促进神经功能的的恢复。研究了环氧化物水解酶抑制剂TPPU在小鼠白质低灌注损伤与功能重建中的作用及相关机制探讨。TPPU干预后可有效减轻脑白质损伤的情况，改善髓鞘结构完整性，抑制低灌注性白质损伤后小胶质细胞活化，减轻相应的炎性反应，促进小胶质细胞向M2型转化，持少突胶质细胞的增殖分化平衡，促进白质连接完整性的恢复及髓鞘再生，最终促进认知功能的恢复。这些结果提示EETs这一组内源性小分子对脑缺血等神经损伤后神经血管单元多细胞靶点具有整体保护作用，对进一步阐明脑缺血的病理机制和探索新的作用靶点，开发新的神经保护药物具有重要的意义。