Targeting methylglyoxal-induced diabetic neuropathic pain through the integrated stress response

糖尿病影响了超过10%的美国人口，另有35%的人面临患糖尿病的迫在眉睫的风险。 多达一半的糖尿病人口会出现慢性疼痛，而目前的治疗方法并不理想。 药物。慢性疼痛是糖尿病患者生活质量不佳的主要原因。而我们却没有 了解糖尿病神经病理性疼痛的确切原因，增加血浆甲基乙二醛(MGO)水平， 能量生产的化学副产品与糖尿病患者的疼痛相关。我们最近展示了 MGO诱导伤害性感受器的整合应激反应(ISR)，使它们成为 极度兴奋。ISR通过抑制真核细胞起始因子2α(eIF2α)和 招募eIF2a到信使核糖核酸翻译机器。这导致了对翻译的全球压制，同时 促进精选信使核糖核酸转录本的翻译，特别是那些具有上游开放阅读框架的转录本。 我们预测，在ISR诱导后eIF2A介导的翻译调节这些细胞的兴奋性 细胞。我们的初步工作表明，ISR参与了糖尿病的小鼠和大鼠模型以及人类模型 用氧化镁处理感觉神经元。我们的主要假设是，ISR会导致糖尿病患者的疼痛和 ISR通路可以作为治疗糖尿病疼痛的靶点。因此，在小鼠身上进行的初步实验缺乏 EIF2A的缺失表明，eIF2A的缺失可以保护这些小鼠免受由 单次或多次注射氧化镁。目标1将利用小鼠遗传学的力量来产生Nav1.8+ 伤害性感受器特异性敲除eIF2A。我们的目标是证明小鼠伤害性感受器中的ISR是MGO所必需的。 诱发和糖尿病神经病理性疼痛。我们将进一步使用这个模型来考察翻译和识别 在eIF2A的影响下，尤其是在MGO处理后，哪些mRNAs被翻译。对于目标2，我们将 使用来自器官捐赠者的培养神经元和神经组织来了解MGO如何改变基因表达 以及ISR抑制剂(ISRIB)能否逆转这些变化 反常的变化。我们获得捐赠者组织提供了一个独特的机会来检验这些假说 具有代表性的模式体系，对本研究将有所裨益。最后，目标3将采取 利用2型糖尿病大鼠模型Zucker糖尿病肥胖(ZDF)大鼠，了解靶向 ISR可用于治疗糖尿病疼痛。我们计划使用目前正在使用的非阿片类药物 ZDF大鼠的发育，如ISRIB。我们的目标是证明以ISR为目标是一种有效的 预防和逆转糖尿病神经病理性疼痛与其电生理的相关性。我们还将表演 用ISRIB处理ZDF大鼠的RNA测序以检测ISR对整个动物的影响 糖尿病模型。通过使用啮齿动物和人类模型，我们将创造一个独特的机会来进行临床建模 使用可用于选择患者和监测药物疗效的特定生物标记物的治疗。终极的 该项目的目标是促进针对ISR的非阿片类药物的发展，如ISRIB

Diabetes affects over 10% of the US population and another 35% are at imminent risk of developing diabetes. As many as half of the diabetic population will develop chronic pain that is poorly treated with current medications. Chronic pain is a major contributor to a poor quality of life in diabetic individuals. While we do not know the exact cause of diabetic neuropathic pain, increases plasma levels of methylglyoxal (MGO), a chemical by-product of energy production, have been correlated with pain in diabetes. We have recently shown that MGO induces the integrated stress response (ISR) in nociceptors, causing them to become hyperexcitable. The ISR controls protein synthesis by repressing eukaryotic initiation factor 2α (eIF2α) and recruiting eIF2A to the mRNA translation machinery. This leads to a global suppression of translation while promoting the translation of select mRNA transcripts, particularly those with an upstream open reading frame. We predict that eIF2A-mediated translation following the induction of ISR regulates the excitability of these cells. Our initial work shows that the ISR is engaged in mouse and rat models of diabetes as well as human sensory neurons treated with MGO. Our overarching hypothesis is that the ISR causes pain in diabetes and that the ISR pathway can be targeted for treating pain in diabetes. As such, initial experiments in mice lacking eIF2A show that the loss of eIF2A protects these mice against evoked and spontaneous pain caused by a single or repeated MGO injections. Aim 1 will harness the power of mouse genetics to generate Nav1.8+ nociceptor-specific knockout of eIF2A. We aim to show that the ISR in mouse nociceptors is required for MGO- evoked and diabetic neuropathic pain. We will further use this model to examine the translatome and identify which mRNAs are translated under the influence of eIF2A, especially after MGO treatment. For Aim 2, we will use cultured neurons and nervous tissues from organ donors to find out how MGO changes gene expression and excitability of human neurons and whether treatment with an ISR inhibitor (ISRIB) can reverse these aberrant changes. Our access to donor tissue presents a unique opportunity to test these hypotheses in a model system that is representative of the people that this research will benefit. Finally, Aim 3 will take advantage of a rat model of type II diabetes, the Zucker Diabetic Fatty (ZDF) rats, to understand how targeting the ISR can be used to treat diabetic pain. We plan to use non-opioid therapies that are currently in development, such as ISRIB, in the ZDF rats. We aim to show that targeting the ISR is an effective strategy for preventing and reversing diabetic neuropathic pain and its electrophysiology correlates. We will also perform RNA sequencing on ZDF rats treated with ISRIB to examine pathways influenced by ISR in a whole animal model of diabetes. By using rodent and human models we will create a unique opportunity to clinically model therapies with a specific biomarker that can be used to select patients and monitor drug efficacy. The ultimate goal of this project is to promote the development of non-opioid therapies targeting the ISR, such as ISRIB