The Role of Base Excision Repair in Regulating DNA-Mediated Inflammatory Signaling Pathways

碱基切除修复在调节 DNA 介导的炎症信号通路中的作用

基本信息

批准号：
10197494
负责人：
Dawit Kidane Mulat
金额：
$ 21.2万
依托单位：
UNIVERSITY OF TEXAS AT AUSTIN
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-04-01 至 2023-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10197494
关键词：
5&apos -deoxyribose phosphate lyase Adenosine Monophosphate Affect Aftercare Aging Base Excision Repairs Cell Line Cells Chemotherapy-Oncologic Procedure Chromatin Chromosomal Instability Chronic Cyclic GMP Cytosol DNA DNA Damage DNA Polymerase beta DNA Repair DNA Repair Gene DNA Single Strand Break DNA glycosylase DNA lesion DNA ligase I DNA ligase III Data Defect Development Dinucleoside Phosphates Disease Endoplasmic Reticulum Equilibrium Excision Exhibits Extravasation Future Gene Mutation Genes Genetic Diseases Genomic Instability Goals Health Homeostasis Human Human Genetics IRF3 gene Immune Immune response Immunotherapy In Vitro Infection Inflammation Inflammatory Inflammatory Response Innate Immune Response Innate Immune System Integral Membrane Protein Interferon Type I Interferon-beta Interferons Knock-in Mouse Lead Left Lesion Link Malignant Neoplasms Mediating Mitochondrial DNA Molecular Mus Mutation Nuclear Nucleotides Outcome Study PARP inhibition Pathway interactions Periodicity Phenotype Physiological Poly(ADP-ribose) Polymerases Polymerase Predisposition Process Production Proteins RTH-1 Nuclease Reporting Research Role Scaffolding Protein Signal Pathway Signal Transduction Single-Stranded DNA Site Source Stimulator of Interferon Genes Sugar Phosphates Surgical incisions Surveys System TBK1 gene Testing XRCC1 gene anti-cancer base cancer cell cancer initiation cancer risk cancer therapy cytokine ds-DNA gene function gene repair genetic variant genome integrity hydroxyl group in vivo Model inhibitor/antagonist innate immune pathways insight loss of function microbial mouse model novel novel strategies prevent recruit repaired response sensor tumor progression tumorigenesis

项目摘要

PROJECT SUMMARY Defects in DNA repair underlie a number of human genetic diseases that affect a wide variety of physiological systems and cause adverse phenotypes such as accelerated aging and predisposition to cancer. Faithful DNA repair is necessary to maintain genomic integrity and prevent cancer. The base excision repair (BER) pathway is responsible for repairing at least 20,000 lesions per cell per day. If left unrepaired, the lesions can give rise to genomic instability and tumorigenesis. BER is also the major repair pathway for nonbulky damaged bases, abasic sites, and DNA single-strand breaks after treatment with different DNA- damaging agents. Several genes are involved in BER pathways, including DNA glycosylase, XRCC1, DNA polymerase beta (Polβ), DNA ligase III, flap endonuclease 1 (FEN1), and DNA ligase I. BER deficiency can lead to accumulated unrepaired DNA damage, generating cytosolic DNA that likely activates DNA-dependent innate immune pathways. Cyclic GMP-AMP synthase (cGAS) is a key cytosolic DNA sensor that produces the cyclic dinucleotide cGMP-AMP (cGAMP) upon activation, which triggers the activation of stimulator of interferon genes (STING), leading to type I Interferon production. However, how deficiency in BER promotes cGAS/STING-mediated inflammation is not yet fully understood. The goal of this exploratory R21 proposal is to uncover how spontaneous DNA damage and failed BER stimulate host inflammatory response. We recently developed a novel mouse model using a human genetic variant, which we will use to elucidate the molecular mechanism of inflammation. Using a Cre-flox targeting system, we constructed an L22P conditional knock-in mouse model that lacks dRP lyase function expressed at Rosa26a locus and cannot support BER. Our preliminary data revealed that BER deficiency in our mouse model markedly induces genomic instability and chronic inflammation. Thus, we hypothesize that BER deficiency accumulates cytosolic DNA that derives from spontaneous DNA damage, thereby triggering the innate immune response. In this study, we propose two Specific Aims: (1) Determine the molecular mechanisms through which aberrant BER induces inflammation. Using BER-deficient cells ( Polβ -/-; XRCC1; PARP1-/-; L22P (dRP lyase-deficient Polβ), we will study how BER deficiency triggers innate immune response-mediated inflammation. (2) Determine whether failed BER stimulates cGAS/STING-mediated inflammation in mice. Using in vitro and in vivo models (L22P mouse models), we will examine how cytosolic DNA-sensing pathways trigger inflammatory immune responses. The outcomes of this study will define a novel paradigm for how aberrant BER induces the innate immune system, and will have broad implications for the molecular mechanisms behind cGAS/STING function, as well as for future immune-directed cancer therapies.

项目概要 DNA 修复缺陷是许多人类遗传疾病的根源，这些疾病影响多种疾病生理系统并导致不良表型，例如加速衰老和易患癌症。忠实的 DNA 修复对于维持基因组完整性和预防癌症是必要的。 (BER) 通路每天负责修复每个细胞至少 20,000 个损伤，如果不修复，病变可引起基因组不稳定，BER也是肿瘤发生的主要修复途径。非大体积受损碱基、无碱基位点和不同 DNA 处理后的 DNA 单链断裂 BER 通路涉及多个基因，包括 DNA 糖基化酶、XRCC1、DNA。聚合酶 β (Polβ)、DNA 连接酶 III、瓣状核酸内切酶 1 (FEN1) 和 DNA 连接酶 I。 BER 缺陷会导致导致累积的未修复的 DNA 损伤，产生可能激活 DNA 依赖性的胞质 DNA 先天免疫途径循环 GMP-AMP 合酶 (cGAS) 是一种关键的胞质 DNA 传感器，可产生环二核苷酸 cGMP-AMP (cGAMP) 激活后，会触发刺激物的激活干扰素基因（STING），导致 I 型干扰素产生。然而，BER 缺陷如何促进。 cGAS/STING 介导的炎症尚未完全了解，该探索性 R21 提案的目标是我们最近揭示了自发性 DNA 损伤和失败的 BER 如何刺激宿主炎症反应。使用人类遗传变异开发了一种新型小鼠模型，我们将用它来阐明分子使用 Cre-flox 靶向系统，我们构建了 L22P 条件敲入。缺乏 Rosa26a 基因座表达的 dRP 裂解酶功能且无法支持 BER 的小鼠模型。初步数据显示，我们的小鼠模型中 BER 缺陷显着导致基因组不稳定，并且因此，我们研究了 BER 缺陷导致的胞质 DNA 的积累。自发性 DNA 损伤，从而触发先天免疫反应。在这项研究中，我们提出了两种具体目标： (1) 确定异常 BER 诱发炎症的分子机制。使用 BER 缺陷的小区（ Polβ -/-；XRCC1-/-；L22P（dRP 裂解酶缺陷） Polβ)，我们将研究如何 BER 缺陷会引发先天免疫反应介导的炎症 (2) 确定 BER 是否失败。使用体外和体内模型（L22P 小鼠）刺激 cGAS/STING 介导的炎症。模型），我们将研究细胞质 DNA 传感途径如何触发炎症免疫反应。这项研究的结果将为异常 BER 如何诱导先天免疫系统定义一个新的范例，将对 cGAS/STING 功能背后的分子机制以及未来的免疫导向癌症疗法。