Regulation of SAMHD1 antiviral activity

SAMHD1 抗病毒活性的调节

• 批准号: 10440395
• 负责人: Felipe Diaz-Griffero
• 金额: $ 56.08万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-20 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10440395
• 关键词: Acetylation; Amino Acids; Anti-Retroviral Agents; Binding; Biochemical; CD4 Positive T Lymphocytes; Cessation of life; Consequentialism; Data; Dendritic Cells; Detection; Development; Enzymes; Exhibits; Genes; HIV Infections; HIV-1; HIV-2; Human; Human Herpesvirus 2; Immune; In Vitro; Infection; Infection prevention; Innate Immune Response; Innate Immune System; Institution; Interferon Type I; Interferons; Knockout Mice; Knowledge; Laboratories; Lentivirus; Life Cycle Stages; Limb structure; Mediating; Medical; Mutation; Natural Immunity; Nucleic Acid Binding; Nucleic Acids; Nucleotides; Paralysed; Patients; Phenotype; Phosphorylation; Preventive vaccine; Privatization; Property; Proteins; Publishing; RNA; Regulation; Reporting; Research Personnel; Resistance; Rest; Reverse Transcription; Role; Structure; T-Lymphocyte; Testing; Therapeutic; Treatment Protocols; Viral; Virus; Virus Diseases; base; in vivo; innate immune function; interest; macrophage; mutant; new therapeutic target; novel; prevent; pseudotoxoplasmosis syndrome; resistant strain; response; sensor; tool; transmission process; tripolyphosphate; viral DNA; viral RNA

Project Summary/Abstract Expression of the recently discovered human restriction factor SAMHD1 is responsible for the infection block imposed to lentiviruses such as HIV-1, HIV-2 and SIVmac by primary macrophages, dendritic cells and resting CD4+ T-cells. SAMHD1 blocks lentiviral infection by preventing the occurrence of reverse transcription. SAMHD1 has deoxynucleotide triphosphohydrolase (dNTPase) activity, which degrades deoxynucleotide triphosphates (dNTPs) into nucleotides and triphosphates, and this activity is required for HIV-1 restriction. However, additional studies have revealed that the dNTPase activity of SAMHD1 is not sufficient for HIV-1 restriction. Thus, an additional property of SAMHD1 is required for HIV-1 restriction. SAMHD1 interacts with nucleic acids in vitro, but the contribution of this interaction to HIV-1 restriction in vivo remains to be determined. Our preliminary data using SAMHD1 mutants indicate that nucleic acid binding is important for HIV-1 restriction. We determined the structure of SAMHD1 bound to an oligodeoxynucleotide and leveraged this structure as a tool for structure-function studies. Several amino acids form the interface between SAMHD1 and the oligodeoxynucleotide, and mutation of these residues resulted in SAMHD1 proteins that are unable to restrict HIV-1. These results suggest that the ability of SAMHD1 to interact with nucleic acids is important for HIV-1 restriction. Separate from its antiviral activity, mutations in the human SAMHD1 gene cause Aicardi- Goutières syndrome (AGS). AGS patients exhibit increased levels of type I interferon (IFN) that are believed to result from the recognition of endogenous nucleic acids by innate immune sensors. Thus, it has been suggested that the in vivo role of SAMHD1 is to prevent activation of the innate immune response by endogenous nucleic acids, and the nucleic acid binding activity of SAMHD1 has been suggested to be important for this function. Our preliminary data indicate that SAMHD1 knockout (KO) mice are resistant to herpes simplex virus 2 (HSV-2)-induced limb paralysis and death. These results suggest that SAMHD1 prevents the recognition of HSV-2 by innate immune sensors, potentially by interacting with the HSV-2 viral DNA and shielding it from detection. This strong phenotype in vivo will be used to unveil the role of SAMHD1 in innate immunity. Based on these published and preliminary results, the central hypothesis of this proposal is that the interaction of SAMHD1 with nucleic acids is important for its antiviral and innate immune functions. Our rationale is that identification of the mechanisms by which SAMHD1 modulates viral infection and innate immune responses will enable the development of novel antiviral and AGS therapies. To test our central hypothesis, we will pursue the following specific aims: 1) Determine the mechanism by which SAMHD1 inhibits HIV-1 infection, 2) Evaluate the role of SAMHD1 acetylation in SAMHD1-mediated viral restriction, and 3) Characterize the role of SAMHD1 in innate immunity.

项目概要/摘要 最近发现的人类限制因子 SAMHD1 的表达是导致感染的原因 原代巨噬细胞、树突状细胞和细胞对慢病毒（例如 HIV-1、HIV-2 和 SIVmac）的阻断 静息 CD4+ T 细胞。 SAMHD1 通过阻止逆转录的发生来阻止慢病毒感染。 SAMHD1 具有脱氧核苷酸三磷酸水解酶 (dNTPase) 活性，可降解脱氧核苷酸 三磷酸（dNTP）转化为核苷酸和三磷酸，这种活性是 HIV-1 限制所必需的。 然而，其他研究表明 SAMHD1 的 dNTPase 活性不足以抑制 HIV-1 限制。因此，限制 HIV-1 需要 SAMHD1 的附加特性。 SAMHD1 相互作用 体外核酸，但这种相互作用对体内 HIV-1 限制的贡献仍有待研究 决定。我们使用 SAMHD1 突变体的初步数据表明，核酸结合对于 HIV-1 限制。我们确定了 SAMHD1 与寡脱氧核苷酸结合的结构，并利用 该结构作为结构功能研究的工具。几个氨基酸形成 SAMHD1 之间的界面 和寡脱氧核苷酸，这些残基的突变导致 SAMHD1 蛋白无法 限制 HIV-1。这些结果表明 SAMHD1 与核酸相互作用的能力对于 HIV-1 限制。与其抗病毒活性不同，人类 SAMHD1 基因的突变会导致艾卡迪- 古蒂埃综合征（AGS）。 AGS 患者的 I 型干扰素 (IFN) 水平升高，据信 是先天免疫传感器识别内源核酸的结果。于是，就已经 表明 SAMHD1 的体内作用是通过以下方式防止先天免疫反应的激活 内源性核酸，并且 SAMHD1 的核酸结合活性被认为是 对于这个功能很重要。我们的初步数据表明 SAMHD1 敲除 (KO) 小鼠对 单纯疱疹病毒 2 (HSV-2) 引起的肢体麻痹和死亡。这些结果表明 SAMHD1 可能通过与 HSV-2 病毒相互作用来阻止先天免疫传感器识别 HSV-2 DNA 并使其不被检测到。这种强烈的体内表型将被用来揭示 SAMHD1 在 先天免疫。根据这些已发表的初步结果，该提案的中心假设 SAMHD1 与核酸的相互作用对其抗病毒和先天免疫非常重要 功能。我们的基本原理是确定 SAMHD1 调节病毒感染的机制 先天免疫反应将促进新型抗病毒和 AGS 疗法的开发。来测试我们的 中心假设，我们将追求以下具体目标： 1）确定 SAMHD1 的机制 抑制 HIV-1 感染，2) 评估 SAMHD1 乙酰化在 SAMHD1 介导的病毒限制中的作用，以及 3) 表征 SAMHD1 在先天免疫中的作用。