T淋巴细胞协同小胶质细胞外泌体靶向AT1aR阳性神经元调控应激性高血压的机制研究

Stress-induced hypertension (SIH) is closely related to sympathetic nervous system overactivity. Recent research in our lab has demonstrated microglial hyperactivation induced autophagy flux blockage in the neurons of rostral ventrolateral medulla (RVLM) in stress-induced hypertension rats. Furthermore, our in vivo experiments show that T lymphocytes and microglia target to AT1aR positive neurons in the RVLM of SIH rats. In addition, our in vitro experiments show that excessive exosomes were released from activated microglia. These results lead us to speculate that microglial exosomes regulates autophagy of AT1aR positive neurons with the guiding effect of T lymphocytes, microglia and T lymphocytes co-regulate SIH. Based on our previous works, in this study, we will conduct a series of in vivo and in vitro experiments, including AT1aR-/- gene knock out, morphology, molecular and cell biology, to investigate this hypothesis. The major research contents would include: (1) the relationship between microglial exosomes and neuronal autophagy, and the molecular regulation mechanism; (2) the route that T lymphocytes infiltrate into the RVLM, and the endocrine-immunoregulatory mechanism of microglial exosomes-targeting AT1aR positive neurons via the guiding effect of T lymphocytes; (3) the mechanism of T lymphocytes/microglia synergistic effect imbalance on sympathetic activity and blood pressure. Based on our previous work, this study will not only reveal the precise mechanism of lymphocytes/microglia in RVLM on co-regulating the SIH, but may also identify a new drug targets for SIH therapy.

应激性高血压(SIH)与交感神经活动亢进紧密关联。申者近期研究已证实SIH大鼠延髓头端腹外侧区(RVLM)小胶质细胞激活引起神经元自噬流障碍，新近实验发现T淋巴细胞在SIH大鼠RVLM内有分布且与小胶质细胞共向AT1aR阳性神经元迁移、细胞实验检测到小胶质细胞激活时释放大量外泌体。故推测“小胶质细胞外泌体调节AT1aR神经元自噬且有T淋巴细胞参与，两者共调控SIH”。本课题拟在前期研究基础上，结合在体、离体实验，采用AT1aR-/-敲除、形态学、分子细胞生物学等技术，研究：(1)小胶质细胞外泌体与AT1aR神经元自噬间的关系及调节机制；(2)T淋巴细胞渗入RVLM途径及其引导小胶质细胞外泌体靶向AT1aR神经元的免疫内分泌机制；(3)T淋巴细胞/小胶质细胞协同效应失衡影响交感活动与血压的机制。本项目在原工作基础上探究T淋巴细胞/小胶质细胞协同调控SIH的精细机理，为SIH的防治提供新靶点。

关键中枢核团调控交感神经活动是防治高血压、逆转血管重构的重要手段之一。延髓头端腹外侧区与下丘脑室旁核在调节应激性高血压发生发展过程中发挥重要作用，本项目较为系统深入地研究了脑内不同类型细胞“串话”、非编码RNA参与高血压发病的分子及神经机制。研究结果发现并证实：1. 应激性高血压诱使外周T淋巴细胞“穿越”血脑屏障侵入下丘脑室旁核，M1小胶质细胞释放炎症细胞因子促使其向Th17细胞分化；2.延髓头端腹外侧区小胶质细胞突触吞噬功能减弱，导致神经元突触密度增加和活动亢进进而引起外周交感超兴奋； 3. 伴随高血压病理进程的加剧，脑内miR-335、miR-674-3p高表达导致交感神经系统过度激活；4. lncRNA INPP5F通过miR-335/Cttn/PI3K-AKT轴调节脑内神经元凋亡, 影响外周交感紧张性进而调节血压变化；5. 过度激活的小胶质细胞趋向M1型转换，并上调炎症因子TNF-α造成线粒体功能障碍, 增强交感神经活动。脑内Th17淋巴细胞、小胶质细胞与神经元互作及非编码RNA协同影响外周交感神经活动，加剧高血压疾病的发生。这些研究成果不仅丰富了中枢调节心血管活动的理论，而且揭示了小胶质细胞互作神经元，以及非编码RNA调控应激性高血压发病的机制，更为高血压的临床治疗提供了新的手段与新的策略。