G6PD缺乏诱导P2X3受体可塑性变化在糖尿病神经病理性疼痛中的作用及机制研究

项目名称： G6PD缺乏诱导P2X3受体可塑性变化在糖尿病神经病理性疼痛中的作用及机制研究

项目编号： No.81471041

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 医药、卫生

项目作者： 胡吉

作者单位： 苏州大学

项目金额： 73万元

中文摘要： 糖尿病痛性神经病变对患者生活质量影响大，机制尚不明确。还原酶G6PD功能减退是引起氧化应激的重要原因，预实验显示：1.糖尿病大鼠后肢特异性脊髓背根节（L4-6 DRG）中G6PD表达下调，NADPH降低，G6PD与P2X3共定位于上述神经元中；2.上述 DRG中ATP配体门控通道P2X3表达上调，神经元ATP电流增加、兴奋性增加；3.可能参与调控P2X3表达的miR31-5p水平降低。由此假设：高糖状态下，G6PD缺乏引起神经元氧化应激，通过降低miR31-5p水平，上调P2X3的表达及功能，增加神经元兴奋性，导致疼痛。本课题将通过在体动物模型和离体研究，探讨：1. 糖尿病神经病理性疼痛模型中是否存在G6PD表达与功能缺乏，后者能否激活P2X3引起疼痛。2.G6PD缺乏参与调控P2X3可塑性（表达与功能）的具体机制。从分子水平解释糖尿病痛性神经病变的形成机制，为治疗提供理论依据。

中文关键词： 糖尿病神经病理性疼痛；脊髓背根神经节；葡萄糖6磷酸脱氢酶；P2X3；受体；小分子RNA31-5p

英文摘要： Painful diabetic peripheral neuropathy is common in diabetic patients, which affects quality of life severely, and the cause of the pain has not been fully elucidated. It is well known that oxidative stress is one of the most important mechanisms underlying diabetic neuropathy and that G6PD deficiency is a major cause of oxidative stress. However, it is not clear whether G6PD takes part in the development of diabetic pain. Recently, we found that the level of G6PD and NADPH were decreased in hind-paw specific DRGs in diabetic rats, and that G6PD was co-localized with P2X3 receptors in DiI labeled hind-paw specific DRG neurons. In addition, neuronal excitability was increased and the ATP evoked currents were enhanced. More importantly, purinergic P2X3 receptor expression in hind-paw specific DRGs was increased in diabetic rats while miR 31-5p expression was reduced which may be involved in the regulation of P2X3 expression. Based on these exciting preliminary data, we hypothesize that (1). Reductase G6PD deficiency plays a crucial role in hind-paw hyperalgesia by up-regulating expression and function of P2X3 receptors and increasing excitability of hind-paw specific DRG neurons in diabetic rats, and (2). Oxidative stress due to reductase G6PD deficiency regulates expression of P2X3 receptors through epigenetic mechanism. To test these hypotheses, we will investigate the following specific aims: Specific Aim 1: To determine the role of G6PD in hind-paw hyperalgesia in diabetic rats; Specific Aim 2: To investigate the epigenetic mechanisms of P2X3 up-regulation due to G6PD deficiency in diabetic rats. VFF and thermal stimulator will be used to record painful behavior in normal and diabetic rats. Patch clamp recordings will be performed in vitro on single hind-paw-specific primary sensory neurons acutely isolated from these rats labeled with DiI. Expression of key nociceptive gene (i.e., G6PD, P2X3, miR31-5P) will be examined with immunocytochemistry, western blotting and (or) RT-PCR analyses. We expect that our studies may clarify mechanisms by which oxidative stress induced epigenetic regulation of key nociceptive genes in the diabetic neuropathy. This added knowledge would provide new strategies for treatment for peripheral neuropathic pain in patients with diabetes.

英文关键词： Diabetic Neuropathic Pain;Dorsal Root Ganglion;G6PD;P2X3 Receptor;microRNA31-5p