CD47-SIRPα调节小胶质细胞吞噬对缺血缺氧性脑损伤后神经血管单元的影响及机制

Neurovascular unit (NVU) is the basic unit of structure and function of central nervous system. Its damage could cause serious consequences. However, its mechanisms of destruction and remodeling in ischemic (HI) brain injury are not yet clear. Microglia is very important for the maintenance of NVU homeostasis. Recent studies have found that CD47-SIRPα inhibits phagocytosis of microglia; blocking CD47 can reduce secondary brain damage. Preliminary work confirms that blocking CD47 could promote endothelial cell proliferation, which is one of the NVU cells. These studies suggest that CD47-SIRPα may be one of the key targets for NVU homeostasis after HI brain injury. The aim of this study was to investigate the effects of blocking CD47 on the microglia phagocytosis and prognosis after HI brain injury; the effects of blocking CD47 on microglia-blood vessel interaction and blood brain barriers breakdown; Effects of CD47-SIRPα on microglia phagocytosis, polarization and NVU cell injury by two-photon microscopy, flow cytometry, immunofluorescence staining and q-PCR both in vivo and in vitro. These studies will lay the theoretical foundation for clarifying the role of microglia in NVU injury after HI brain injury, elucidating its molecular mechanisms and finding new therapeutic targets.

神经血管单元（NVU）是中枢神经系统结构功能的基本单位，它的损伤会引起严重后果，然而其在缺血缺氧性（HI）脑损伤中破坏和重塑机制尚不十分清楚。小胶质细胞对于NVU稳态的维持非常重要。近期研究发现CD47-SIRPα可抑制小胶质细胞的吞噬功能；阻断CD47可减轻继发性脑损伤。前期工作证实阻断CD47可促进NVU中的内皮细胞增殖。提示CD47-SIRPα可能是HI脑损伤后NVU稳态改变的关键靶点之一。本项目拟建立HI损伤的体内、外模型，通过双光子显微镜、流式细胞术、免疫荧光染色、q-PCR等技术进一步研究：阻断CD47对HI脑损伤后小胶质细胞吞噬及预后的影响；对小胶质细胞-血管相互作用及血脑屏障的影响；CD47-SIRPα在小胶质细胞吞噬、极化及NVU细胞损伤中的作用。这些研究将为明确小胶质细胞在HI脑损伤后NVU损伤过程中的作用、阐明其分子机制及寻找新的治疗靶点奠定理论基础。

我们按照标书计划通过模拟体内外神经血管单元细胞损伤，研究CD47参与调控对小胶质细胞的清除功能及机制，以及评估干预CD47信号通路对HI脑损伤后神经血管单元细胞修复的效果，并且对野生型以及CD47缺失的内皮细胞进行了检测。由于实验过程中，在造损伤模型的同时我们发现环境温度对内皮细胞的损伤非常明显，比如环境温度过高后，内皮细胞增殖受到限制，形态发生变化，细胞凋亡数量明显增加，同时衰老指标提高等多种现象。继而，我们将工作重心放在针对温度调节内皮细胞机能方面的研究上，通过一系列的实验发现，温度调节细胞周期的机制是通过调控细胞运动机能，紊乱有丝分裂的进行而实现的。证明环境温度调节细胞周期的机制是调控细胞运动机能，紊乱有丝分裂的进行而实现的，这一结果为全面了解环境温度参与细胞周期以及细胞迁徙的机制奠定理论基础，同时也为其在临床上的实际应用提供重要依据。