Biochemistry of SAMHD1-mediated innate immunity responses

SAMHD1 介导的先天免疫反应的生物化学

• 批准号: 10212922
• 负责人: DMITRI N IVANOV
• 金额: $ 46.91万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-01 至 2023-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10212922
• 关键词: Adopted; Affinity; Allosteric Regulation; Allosteric Site; Anti-Retroviral Agents; Antiviral Agents; Autoimmune Diseases; Back; Bacterial DNA; Binding; Binding Sites; Biochemical; Biochemistry; Biological; Biological Models; Biophysics; Cells; Collaborations; Cysteine; DNA Repair; Data; Defect; Defense Mechanisms; Enzymes; Evolution; Family; Genome; Goals; Guanine Nucleotides; Guanosine Triphosphate; HIV; HIV Infections; HIV-1; HIV-2; Hydrolase; Hydrolysis; Immune; Immune response; Immunologic Factors; Infection; Innate Immune Response; Interferons; Intervention; Laboratories; Ligands; Light; Link; Mediating; Messenger RNA; Metabolism; Molecular; Mutation; Myelogenous; Myeloid Cells; Natural Immunity; Nucleic Acid Binding; Nucleic Acids; Nucleosides; Nucleotides; Oligonucleotides; Oxidation-Reduction; Pathogenesis; Pathway interactions; Pattern; Play; Post-Transcriptional Regulation; Post-Translational Regulation; Predisposition; Prevention; Property; Proteins; Reactive Oxygen Species; Regulation; Resistance; Rest; Reverse Transcription; Role; SIV; Sampling; Second Messenger Systems; Shapes; Signal Pathway; Signal Transduction; Source; Structure; T-Lymphocyte; Viral; Viral Proteins; Viral reservoir; Virus; Virus Diseases; Virus Latency; Virus Replication; Work; antiviral immunity; cell growth regulation; immune function; innate immune pathways; innate immune sensing; insight; member; novel; pathogenic virus; phosphorothioate; protein function; pseudotoxoplasmosis syndrome; response; tool; treatment strategy; tripolyphosphate

ABSTRACT SAMHD1, a mammalian member of the HD-domain hydrolase family of enzymes, catalyzes hydrolysis of deoxynucleotides triphosphates (dNTPs) to triphosphate and unphosphorylated nucleosides, which is thought to be the main pathway for controlled depletion of cellular dNTPs. Discoveries that SAMHD1 is an immune factor that restricts retroviral replication in non-cycling immune cells and regulates interferon signaling revealed that dNTP depletion may act as a defense mechanism of innate antiviral immunity. Existence of such mechanism implies that the enzymatic activity of SAMHD1 must be controlled by pathways of innate immune sensing and response, and that cellular regulation of SAMHD1 is key to understanding the functional relationship between antiviral immunity and dNTP metabolism. In the studies described here we will use unique experimental tools developed by my laboratory to elucidate how biochemical regulation of SAMHD1 determines its immune function. This project will explore two novel regulatory mechanisms that have emerged from our preliminary work and establish their contribution to the SAMHD1-mediated anti-retroviral state in non- cycling immune cells. The studies will shed light on how and possibly why different molecular clues and cellular signaling pathways alter susceptibility of myeloid and resting T cells to HIV infection, and thus elucidate the biological significance of SAMHD1 function at the interface of dNTP metabolism and antiviral defense. In a continued collaboration with the laboratory of Dr. Diaz-Griffero we will pursue two major specific aims. In Aim 1 we will explore the role of nucleic acid binding in the immune function of SAMHD1, elucidate structural and biochemical determinants of high-affinity interaction of SAMHD1 with oligonucleotides and determine what nucleic acid species regulate SAMHD1 activity and why. Our preliminary data suggest that phosphorothioate linkages in nucleic acids may act as a danger-associated molecular pattern or a second messenger in antiviral immunity. In Aim 2 we will elucidate the mechanism linking redox transformations of SAMHD1 to the enzymatic activity and the immune function of the protein. Our preliminary studies suggest that redox regulation of SAMHD1 may offer insight into the emerging role of reactive oxygen species (ROS) in modulating innate antiviral immunity. We will determine what redox states are sampled by the redox-active cysteines of SAMHD1, how these transformations alter the biochemical properties of the protein and explore whether SAMHD1 activity is controlled by specific sources of ROS and signaling pathways in the cell.

摘要 SAMHD1是HD结构域水解酶家族中的一个哺乳动物成员，它催化 脱氧核苷酸三磷酸(DNTPs)为三磷酸和非磷酸化核苷，这被认为 是细胞dNTPs受控耗竭的主要途径。发现SAMHD1是一种免疫 限制非循环免疫细胞中逆转录病毒复制并调节干扰素信号的因素已公布 DNTP的耗竭可能是先天抗病毒免疫的一种防御机制。这种情况的存在 机制提示SAMHD1的酶活性必须受天然免疫途径的控制 SAMHD1的细胞调控是理解功能的关键 抗病毒免疫与dNTP代谢的关系在这里描述的研究中，我们将使用 我的实验室开发了独特的实验工具来阐明SAMHD1的生化调节 决定了它的免疫功能。这个项目将探索已经出现的两种新的监管机制 从我们的初步工作中确定他们对SAMHD1介导的抗逆转录病毒状态的贡献 循环免疫细胞。这些研究将阐明不同的分子线索和细胞 信号通路改变髓系和静息T细胞对HIV感染的敏感性，从而阐明 SAMHD1功能在dNTP代谢和抗病毒防御中的生物学意义在一个 继续与Diaz-Griffero博士的实验室合作，我们将追求两个主要的具体目标。在目标1中 我们将探讨核酸结合在SAMHD1免疫功能中的作用，阐明SAMHD1的结构和 SAMHD1与寡核苷酸高亲和力的生化决定因素及其确定 核酸物种调节SAMHD1的活性及其原因。我们的初步数据显示，硫代磷 核酸中的连接可能作为危险相关的分子模式或抗病毒药物中的第二信使 豁免权。在目标2中，我们将阐明SAMHD1的氧化还原转化与酶的联系的机制 蛋白质的活性和免疫功能。我们的初步研究表明，氧化还原调节 SAMHD1可能有助于深入了解活性氧簇(ROS)在调节先天代谢中的新作用 抗病毒免疫。我们将确定SAMHD1的氧化还原活性半胱氨酸采样了哪些氧化还原状态， 这些转化如何改变蛋白质的生化特性，并探索SAMHD1 活性受细胞内特定的ROS来源和信号通路控制。