GLP-1受体激动剂作用于大脑小胶质细胞改善糖尿病神经病理性疼痛的机制研究

Diabetic neuropathic pain seriously affects the quality of life of diabetic patients. The current therapeutic effect is far from satisfied. The new therapy target should be explored. In positron emission tomography (PET) imaging study, we used specialized tracer for in vivo imaging of microglia response and found that the activation of microglia was significantly increased in diabetic neuropathic pain rats brain. Furthermore,the role of microglia in brain is still out of research. Glucagon like peptide -1 (GLP-1) receptors expressed on micrglia in the brain. And our study showed that GLP-1 receptor agonist could alleviate STZ induced diabetic neuropathic pain in rats. Therefore, we observed the role of GLP-1 receptor agonist on cultured microglia in cell experiments, and found that GLP-1 receptor agonist regulated the expression of molecular STAT3 and improved the activation of microglia. Therefore, we hypothesized that GLP-1 receptor agonist alleviated diabetic neuropathic pain through the brain microglia via the regulation of STAT3. Our hypothesis will be proved in the animal, cell and molecular levels in this study. Our study may provide new insights in the therapy of diabetic neuropathic pain.

糖尿病神经病理性疼痛严重影响糖尿病患者的生活质量，其机制尚不明确且治疗效果欠佳，需要不断深入研究其机制，寻找治疗的新靶点。本课题组采用特异标记小胶质细胞的示踪剂行PET-CT检查，显示糖尿病神经病理性疼痛大鼠大脑小胶质细胞明显活化，而大脑层面的小胶质细胞活化在糖尿病神经病理性疼痛的作用尚未见报道。大脑小胶质细胞表达GLP-1受体，通过动物研究我们也初步发现GLP-1受体激动剂可改善糖尿病大鼠的神经病理性疼痛，因此我们初步在细胞水平观察了GLP-1受体激动剂干预小胶质细胞活化，结果显示GLP-1受体激动剂可以调节STAT3分子水平，并显著改善小胶质细胞活化。因此我们提出假设：GLP-1受体激动剂通过STAT3分子作用于大脑小胶质细胞，从而改善糖尿病神经病理性疼痛。本研究拟在动物水平、细胞水平和分子水平验证提出的假设，为糖尿病神经病理性疼痛治疗提供新思路。

结题摘要.1、.研究背景.小胶质细胞激活在糖尿病神经病理性疼痛（Diabetic neuropathic pain, DNP）的发病中起到重要作用。本课题组前期通过PET/CT观察到DNP大鼠脑内小胶质细胞明显激活。既往文献报道胰高糖素样肽-1受体激动剂（Glucagon-like peptide-1 receptor agonist, GLP-RA）可通过脊髓小胶质细胞显著缓解DNP，但GLP-1RA是否可通过大脑小胶质细胞改善DNP尚未见报道。本课题拟探究GLP-1RA通过大脑小胶质细胞改善DNP的可能机制。.2、研究内容.对DNP大鼠外周或侧脑室注射GLP-1RA，观察GLP-1RA对DNP的治疗效果。在体外实验明确GLP-1RA对小胶质细胞激活的抑制作用。此外，通过转录组学寻找GLP-1RA通过大脑小胶质细胞改善DNP的可能靶点，并在细胞和动物水平进行验证。明确GLP-1RA是否可通过AKT/糖原合成激酶3β（glycogen synthesis kinase-3β，GSK3β）通路抑制NOD样受体蛋白3（NOD-like receptor protein 3, NLRP3）炎症小体激活。.3、研究结果.我们发现外周注射或侧脑室注射GLP-1RA均可显著改善DNP大鼠的机械痛和热痛痛敏。且GLL-1RA可抑制小胶质细胞分泌TNF-α和IL-6。转录组学结果显示NLRP3炎症小体可能是GLP-1RA通过大脑小胶质细胞改善DNP的靶点，且细胞水平和动物水平验证发现GLP-1RA可抑制小胶质细胞NLRP3炎症小体激活。进一步我们发现GLP-1RA可通过AKT/GSK3β通路抑制NLRP3炎症小体激活。.4、主要科学意义.本课题发现GLP-1RA可通过AKT/GSK3β通路抑制NLRP3炎症小体激活，进而可能参与改善DNP，为DNP的临床治疗提供了新手段。