Therapeutics of mTOR Signaling in Succinic Semialdehyde Dehydrogenase Deficiency

描述（由申请人提供）：丁二酸半醛脱氢酶（SSADH；醛脱氢酶5a1）缺乏症仍然是GABA（4-氨基丁酸）代谢最普遍的疾病，在GABA和GHB （γ -羟基丁酸）两种神经调节剂的增加中是独一无二的。在它被发现大约30年后，有效的药物治疗仍然难以捉摸。我们最近在酵母中发现了GABA作为选择性自噬途径（噬噬和有丝分裂）抑制剂的意想不到的作用，这一过程是通过Sch9（哺乳动物核糖体S6激酶1的同源物，S6K1）激活介导的，并与氧化损伤相关。前期研究表明，mTOR抑制剂雷帕霉素可以下调Sch9，干预可以显著减轻小鼠模型中gaba相关的病理，包括减少增加的线粒体数量，改善氧化应激参数，减轻异常细胞信号传导。我们的主要假设是，抑制mTOR信号传导和/或诱导自噬的治疗方法将为以GABA升高为特征的遗传性疾病提供一种创新的治疗方法，同时为靶向中枢神经系统（CNS） GABA增加的药物治疗提供信息。目的1将在aldh5a1-/-小鼠中检测mTOR抑制（雷帕霉素、torin1、替西莫司）的生理、生化和细胞效应。目的2将检查所选药物在原代培养的aldh5a1-/-细胞中覆盖自噬和有丝自噬破坏的能力。我们的研究设计将是两个目标的2x2因子混合模型，采用方差分析和事后分析进行统计分析。我们结合细胞和动物研究的基本原理是基于我们的预测，即体外研究将有助于阐明gaba相关的病理机制，而体内研究将为临床干预提供更快速的途径。该项目将为GABA在人类生物学中的作用提供新的科学依据，积累临床前动物数据，为CNS GABA升高的疾病的新治疗方法铺平道路，并为选择以增加GABA为药理目标的抗癫痫药物的使用提供新的见解。我们正在根据我们的初步研究评估合理的治疗方法，但如果没有额外的临床前数据，这些治疗方法无法在人类中进行试验。我们的实验室已经将牛磺酸和SGS-742用于SSADH缺乏症的临床前动物实验，强调了当前项目成功的潜力。

DESCRIPTION (provided by applicant): Succinic semialdehyde dehydrogenase (SSADH; aldehyde dehydrogenase 5a1) deficiency remains the most prevalent disorder of GABA (4-aminobutyrate) metabolism, one that is unique in the accretion of two neuromodulators, GABA and GHB (gamma-hydroxybutyric acid). Some 30 years after its discovery, effective pharmacotherapy remains elusive. We recently unmasked in yeast an unexpected role for GABA as an inhibitor of selective autophagy pathways, pexophagy and mitophagy, a process mediated via Sch9 (homolog of mammalian ribosomal S6 kinase 1, S6K1) activation and associated with oxidative damage. Pilot studies have demonstrated that intervention with the mTOR inhibitor, rapamycin, which down-regulates Sch9, can significantly mitigate GABA-related pathology in the murine model, including reducing increased mitochondrial number, improving oxidative stress parameters, and mitigating aberrant cell signaling. Our primary hypothesis posits that therapeutics inhibiting mTOR signaling and/or inducing autophagy will provide an innovative therapeutic approach to heritable disorders featuring GABA elevation, while informing pharmacotherapies that target increased GABA increase in central nervous system (CNS). Aim 1 will examine the physiological, biochemical and cellular effects of mTOR inhibition (rapamycin, torin1, temsirolimus) in aldh5a1-/- mice. Aim 2 will examine the capacity of selected drugs to override disruptions of pexophagy and mitophagy in primary cultures of aldh5a1-/- cells. Our study design will be a 2x2 factorial mixed model for both aims, employing ANOVA with post hoc analyses for statistical analyses. Our rationale for combined cellular and animal studies centers on our prediction that in vitro studies will serve to elucidate GABA-related pathomechanisms, while in vivo studies will outline a more rapid route to clinical intervention. This project will beak new scientific ground on the role of GABA in human biology, accrue preclinical animal data that will pave the way for novel therapeutics in disorders with elevated CNS GABA, and provide new insights on the use of selected antiepileptics whose pharmacological objective is to increase GABA. We are evaluating rational therapies based upon our pilot studies, but these therapies cannot be piloted in humans without additional preclinical data. Our laboratory has already spring-boarded preclinical animal data using taurine and SGS-742 into human clinical trials in SSADH deficiency, underscoring the potential for success in the current project.