内源性Angiotensin Ⅱ通过脊髓背角星形胶质细胞谷氨酸转运体-1 (GLT-1)调控糖尿病神经病理性痛的机制研究

Diabetic neuropathic pain (DPN) is a clinically refractory pain and there are currently no effective treatments. Recent studies have shown that dorsal horn astrocytes of spinal cord play an important role in the development and maintenance of neuropathic pain.The glutamate transporter-1(GLT-1) exclusively expressed on the astrocytes which probably correlates with astrocytes activation. The level of endogenous angiotensin Ⅱ (AngⅡ) was significantly increased in cerebral spinal fluid (CSF) of DPN model mice. It is likely that Ang II causes DPN involving GLT-1 by activating the AT1R on spinal dorsal horn astrocytes. Based on the existing data, the DPN model will be used to generate DPN transgenic mice that selectively knockout AT1R on astrocytes by using Cre-loxp recombinase system in this project. Combining with animal behavior, liquid chromatography–mass spectrometry, patch-clamp technique, radioisotope and molecular biology methods to explore the mechanism of endogenous AngⅡ regulating GLT-1 on astrocytes in DNP in the molecular level, cell level, tissue level and overall level.

糖尿病神经病理性痛(DPN)是临床上难治的疼痛，目前尚无有效的治疗药物。近年来研究显示，脊髓背角星形胶质细胞在神经病理性疼痛产生和维持过程扮演重要角色。谷氨酸转运体-1(GLT-1)，主要表达在星形胶质细胞上，参与星形胶质细胞活化。DPN模型小鼠脑脊液中内源性血管紧张素II (Angiotensin Ⅱ,AngⅡ）水平显著升高。AngⅡ很可能通过激活脊髓背角星形胶质细胞血管紧张素Ⅱ-1型受体（Angiotensin II type 1 receptor, AT1R）调控GLT-1参与DPN产生。本项目将在已有研究基础上，采用DPN模型，利用Cre-loxp重组酶系统实现选择性敲除星形胶质细胞AT1R的DPN疼痛转基因模型小鼠，结合动物行为学、液相色谱-串联质谱法、膜片钳技术、放射同位素及分子生物学方法，从分子、细胞、组织及整体水平探讨内源性AngⅡ调控星形胶质细胞GLT-1产生DNP机制。

糖尿病神经病理性痛(DPN)是临床上难治的疼痛，目前尚无有效的治疗药物。近年来研究显示，脊髓背角星形胶质细胞在神经病理性疼痛产生和维持过程扮演重要角色。本项目在整体水平上 明确主要蛋白（Ang II、AT1R、JAK-STAT3、GLT-1）在脊髓背角定位和分布；证实Ang II、AT1R、JAK-STAT3信号通路参与调控神经病理性疼痛（DNP）。在脊髓背角组织水平上，通过基因、蛋白和（或）功能水平比较脊髓背角AT1R、JAK-STAT3和（或）GLT-1组间差异性，证实了内源性AngII通过激活脊髓背角星形胶质细胞JAK-STAT3调控GLT-1功能及表达参与DNP产生机制；细胞、分子水平上，利用免疫荧光技术、WesternBlot 蛋白印迹技术分析AT1R、JAK-STAT3调控GT 胞吞（Endocytosis）机制。研究结果显示DPN模型小鼠脑脊液中内源性血管紧张素II (Angiotensin Ⅱ,AngⅡ）水平显著升高；选择性敲除脊髓背角星形胶质细胞AT1受体小鼠星形胶质细胞GLT-1表达较对照组表达增加；DPN疼痛模型小鼠脊髓背角星形胶质细胞GLT-1较对照组表达显著减少；证实了AngⅡ通过脊髓背角星形胶质细胞AT1受体激活JAK-STAT3通路，进而下调GLT-1功能及表达，从而促进DNP发生发展。这一研究成果为临床医学中的转化一个重要的课题，为神经病理性疼痛的形成及神经病理改变提出明确的观点，确定病理性疼痛的干预靶点，并为临床防治病理性疼痛提供切实的理论依据。