Neuroprotective actions of cystathionine g-lyase through gasotransmitter hydrogen sulfide signaling

项目总结 胱硫醚γ裂解酶通过气体递质硫化氢的神经保护作用 发信号。 硫化氢(H_2S)是一种气体信号分子或气体传递体，在体内起着关键作用。 中枢神经系统。然而，硫化氢在大脑中作用的具体靶点和机制尚不清楚。 在此，我们建议阐明大脑中受硫化氢调制的信号通路。 达到针对阿尔茨海默病(AD)的治疗方法的神经保护。硫化氢是从氨基生成的。 酸性半胱氨酸，进而由胱硫醚γ裂解酶(Cse)通过硫化途径合成 在大脑里。硫化氢也是由另外两种酶--胱硫醚β-合成酶(Cbs)和3-硫代半胱氨酸合成酶(3-cbs)合成的。 大脑中的巯基丙酮酸硫转移酶(3-MST)。我们以前已经证明过，硫化氢和 阿尔茨海默病患者半胱氨酸代谢紊乱。硫化氢信号的一种方式是通过翻译后 修饰称为硫水化或过硫化，其中半胱氨酸残基上的反应性-SH基团 以类似于一氧化氮(NO)亚硝化的方式将靶蛋白转化为AN-SSH基团， 其中-SH基团被转化为-SNO基团。尽管硫水化和亚硝化调节 不同的生理过程，从反应到炎症到神经保护，分子 半胱氨酸和H_2S/NO轴影响神经功能的机制如下 还没有被破译。在本项目的目标1中，我们将监测三种硫化氢的表达和活性 不同年龄小鼠脑内的生物合成酶，CSE，CBS和3-MST。中的硫化状态 正常以及缺乏CSE的小鼠将被评估。经过硫水化修饰的特定蛋白质将是 已确定，并绘制了其上的硫水化位置。硫水化反应与亚硝化反应的相互作用 将监测神经功能。在目标2中，我们将分析硫化氢在应激反应中的作用 和行为。在目标3中，我们将在3xTg-AD小鼠模型中鉴定差异硫化蛋白。 广告。 通过研究CSE和硫化氢在大脑中的功能，我们设定了一个目标，以更好地理解信号 阿尔茨海默病中神经元信号转导中的半胱氨酸、硫化氢和蛋白质水合作用。理解 调节大脑中的硫化氢信号有助于确定参与的基本生理通路。 神经保护和定位节点用于AD的精确治疗和生物标记物的开发 以及其他与年龄相关的神经退行性疾病，涉及硫化氢信号失控。 1

PROJECT SUMMARY Neuroprotective actions of cystathionine γ-lyase through gasotransmitter hydrogen sulfide signaling. Hydrogen sulfide (H2S) is a gaseous signaling molecule or gasotransmitter which serves key roles in the central nervous system. However, specific targets and mechanisms of H2S action in the brain are obscure. Herein, we propose to elucidate the signaling pathways modulated by H2S in the brain that are neuroprotective to arrive at therapeutics targeting Alzheimer's disease (AD). H2S is generated from the amino acid cysteine which, in turn, is synthesized by cystathionine γ-lyase (CSE) via the transsulfuration pathway in the brain. H2S is also synthesized by two other enzymes, cystathionine β-synthase (CBS) and 3- mercaptopyruvate sulfurtransferase (3-MST), in the brain. We have demonstrated previously, that H2S and cysteine metabolism are dysregulated in AD. One of the modes by which H2S signals is via a posttranslational modification termed sulfhydration or persulfidation, wherein the reactive –SH group of cysteine residues on target proteins is converted to an –SSH group in a fashion analogous to nitrosylation by nitric oxide (NO), where the –SH groups are converted to –SNO groups. Although sulfhydration and nitrosylation modulate diverse physiological processes ranging from response to inflammation to neuroprotection, the molecular mechanisms by which cysteine and H2S/NO axes of gasotransmitter signaling affect neuronal function are yet to be deciphered. In Aim 1 of this project, we will monitor expression and activity of the three H2S biosynthetic enzymes, CSE, CBS and 3-MST in the mouse brain at various ages. Sulfhydration status in normal as well as mice lacking CSE will be assessed. The specific proteins modified by sulfhydration will be identified, and sites of sulfhydration mapped on them. The interplay of sulfhydration with nitrosylation in neuronal function will be monitored. In Aim 2, we will analyze the involvement of H2S in stress responses and behavior. In Aim 3, we will identify differentially sulfhydrated proteins in the 3xTg-AD mouse model of AD. By studying the function of CSE and H2S in the brain, we set a goal to better understand signaling mediated by cysteine, H2S and protein sulfhydration in the context of neuronal signaling in AD. Understanding the regulation of H2S signaling in the brain helps to determine the basic physiological pathways involved in neuroprotection and pins down the nodes for precision therapeutics and development of biomarkers for AD and other age-related neurodegenerative diseases involving dysregulated H2S signaling. 1