下丘脑室旁核小胶质细胞激活参与高血压发病机制的研究

The hypothalamic paraventricular nucleus (PVN) is an important central site for integration of sympathetic nerve activity. Recent studies have demonstrated that the activation of the PVN contributes to the pathogenesis of hypertension. A growing body of evidence has focused on the effects of neurons in the PVN, however very few studies have explored the role of activated microglia in the PVN in the pathogenesis of hypertension. The relationship between the neurons and the microglia in PVN is unclear. In this study, we will conduct a series of experiments in vivo and in vitro to investigate the microglial mechanisms of hypertension, by using conditional gene knockout techniques, cell co-culture techniques, cytokine chip techniques, siRNA techniques, chronic bilateral PVN infusion techniques, microglial cells transfusion techniques and molecular biology techniques. We will utilize spontaneously hypertensive rats, angiotensin II-induced hypertensive rats and Csf1r conditional knockout mice to determine the involvement of activated microglial cells in the pathogenesis of hypertension. In addition, we will investigate whether microglial cells release proinflammatory cytokines through TLR4/MyD88/NF-κB signaling pathway, and the proinflammatory cytokines released by the activated microglia stimulate PVN neurons; and then activated neurons in PVN induce activation of renin-angiotensin system, overproduction of reactive oxygen species, high levels of proinflammatory cytokines, imbalance of neurotransmitters, and the activation of NF-κB, which cause renal sympathetic hyperactivity, vascular dysfunction and hypertensive responses. Wild type and Csf1r conditional knockout mice will be utilized to confirm this hypothesis. Further exploration of the detailed mechanisms of the interactions between microglial cells and neurons within the PVN may be beneficial towards the development of novel hypertensive therapeutics. The present study will provide new insights into the activated neurons and the activated microglial cells in the PVN in hypertension, which contributes to expand our knowledge about the pathogenesis of hypertension. This study will provide potential targets for prevention and treatment of hypertension and so have important clinical implications.

以往对下丘脑室旁核活动增强引发交感神经过度兴奋参与高血压发病机制的研究多着眼于室旁核神经元，但室旁核小胶质细胞激活在高血压发生发展中的作用及其机制尚不清楚。本项目拟采用高血压模型大鼠、Csf1r条件性基因敲除小鼠，证实室旁核小胶质细胞激活参与高血压的发生发展；采用室旁核小胶质细胞原代培养结合细胞因子芯片及siRNA等分子生物学技术，阐明高血压时室旁核激活的小胶质细胞通过TLR4/MyD88/NF-κB信号通路介导炎性细胞因子释放的机制；采用室旁核原代小胶质细胞和神经元共培养、双侧室旁核慢性给药及小胶质细胞回输等技术明确高血压时室旁核激活的小胶质细胞通过释放炎性细胞因子引起室旁核神经元炎性反应、肾素-血管紧张素系统和NF-κB激活，氧化应激增强和神经递质失平衡进而导致交感神经活动增强和血压升高。本项目可望阐明室旁核小胶质细胞激活参与高血压的发病机制，为高血压的治疗提供新的实验依据和干预靶点。

以往对高血压中枢机制的研究多着眼于下丘脑室旁核神经元，但室旁核小胶质细胞激活在高血压发生发展中的作用及其机制尚不清楚。本项目主要研究高血压时室旁核激活的小胶质细胞作用于室旁核神经元，进而影响交感神经活动和血压的机制。.本项目主要取得以下重要研究结果：(1) 室旁核小胶质细胞激活引起室旁核炎性细胞因子(PIC)和活性氧簇(ROS)产生增多，交感神经活动增强和血压升高；(2) 高血压时室旁核小胶质细胞激活，室旁核兴奋性和抑制性神经递质失平衡，交感神经活动增强，血浆去甲肾上腺素水平升高和血压升高；抑制高血压大鼠室旁核小胶质细胞的激活可使交感神经活动减弱，血浆去甲肾上腺素水平降低和血压降低；(3) 高血压时室旁核小胶质细胞激活引起室旁核炎性细胞因子和抗炎性细胞因子失平衡， ROS产生增多；经双侧室旁核慢性给予小胶质细胞抑制剂米诺环素可改善高血压大鼠室旁核炎性细胞因子和抗炎性细胞因子失平衡，降低氧化应激水平，减弱交感神经活动，进而改善高血压；(4) 高血压时室旁核小胶质细胞激活可引起室旁核TLR4/MyD88/NF-κB信号通路激活；抑制室旁核TLR4/MyD88/NF-κB信号通路可改善高血压大鼠室旁核炎性细胞因子和抗炎性细胞因子失平衡，降低氧化应激水平，减弱交感神经活动，进而改善高血压。.本项目揭示了高血压时室旁核小胶质细胞激活影响交感神经活动和血压变化的多种调控机制。本项目研究发现高血压时下丘脑室旁核小胶质细胞被激活,激活的小胶质细胞可通过激活TLR4/MyD88/NF-κB信号通路介导炎性细胞因子释放，参与高血压的发生发展；发现高血压时下丘脑室旁核过度活化的小胶质细胞通过影响室旁核神经元ROS、PIC和神经递质相互作用，进而引起交感神经活动增强和血压升高。抑制室旁核小胶质细胞的激活可减弱交感神经活动和改善高血压。本项目的研究成果为高血压的预防、治疗及新药研发提供实验依据和新思路。.本项目的研究已经达到预期目标，相关研究成果发表40篇SCI收录期刊论文，研究期间指导博士后6名、培养博士生9名和硕士生9名，项目研究期间已毕业博士生4名和硕士生5名。