New roles of IFN-inducible OAS proteins in innate immune defense against bacterial infections

IFN诱导的OAS蛋白在针对细菌感染的先天免疫防御中的新作用

• 批准号: 10649771
• 负责人: Vijay Rathinam
• 金额: $ 68.67万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-01-23 至 2027-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10649771
• 关键词: 2019-nCoV; Address; Anti-Bacterial Agents; Autoimmune Diseases; Bacteria; Bacterial Antibiotic Resistance; Bacterial Genes; Bacterial Infections; Binding Proteins; Biochemical; Biological; Cells; Communicable Diseases; Data; Development; Family; Francisella tularensis; Gene Family; Genes; Genetic Polymorphism; Goals; Homologous Gene; Host Defense; Human; IRF1 gene; Immune; Impairment; In Vitro; Infection; Inflammatory; Innate Immune Response; Interferon Type I; Interferons; Knock-in Mouse; Knowledge; Length; Ligase; Link; Listeria monocytogenes; Macrophage; Mediating; Mediator; Modeling; Molecular; Mus; Natural Immunity; Orthologous Gene; Play; Population; Predisposition; Production; Protein Family; Protein Isoforms; Protein Synthesis Inhibition; Proteins; Publishing; RNA Degradation; Regulation; Ribonucleases; Role; Signal Transduction; Testing; Transferase; Translations; Up-Regulation; Viral; Viral Physiology; Virus Diseases; antimicrobial; cell type; cytokine; design; experimental study; genome wide association study; guanylate; in vivo; innate immune function; innovation; insight; member; mouse model; novel therapeutic intervention; oligoadenylate; response; transcription factor

ABSTRACT Type I interferons (IFN) and IFN stimulated genes (ISGs) provide broad antiviral activities. However, the host protection provided by the IFN and ISGs during bacterial infections is not well defined. This proposal will define new innate immune functions of Oligoadenylate Synthetase (OAS) proteins against intracellular bacterial infections. OASs are a family of ISG that belongs to an evolutionarily ancient family of nucleotidyl-transferases (NTase). The canonical antiviral mechanism of OAS proteins involves the enzymatic synthesis of 2'-5'- oligoadenylates, causing downstream activation of RNase L, leading to RNA degradation and inhibition of protein synthesis. However, the host protective function of multiple enzymatically active and inactive OAS isoforms during bacterial infection is not known. This proposal will address this knowledge gap to define the innate antibacterial functions of two OAS family proteins, OAS1 and OASL. Our preliminary studies suggest that human OAS1 and a mouse ortholog, Oas1b, confer protection from infection with intracellular bacteria by enhancing the expression of several proteins including IRF1, a major antibacterial transcription factor. Furthermore, we found that mice lacking Oasl2 (ortholog of human OASL), another member of OAS family, are highly susceptible to intracellular bacterial infection, and show increased production of host-detrimental inflammatory cytokines. Based on these preliminary findings, we hypothesize that specific members of OAS- family proteins contribute to host defense against intracellular bacteria through unique NTase activity- independent mechanisms. The goal of this proposal is to determine the innate antibacterial functions of two OAS family proteins and the underlying mechanisms in three independent aims: (1) Identify the mechanisms of cell- intrinsic antibacterial activity of OAS1. Here, we will define the molecular mechanism by which OAS1 mediates cell intrinsic antibacterial defense using in vitro biochemical and cell biological approaches. (2) Determine the in vivo role of Oas1b in anti-bacterial innate immunity. We will use a newly generated Oas1b knock-in mouse model to identify the in vivo mediators and cell-type specific antibacterial function of Oas1b. (3) Define the role of OASL in host defense against intracellular bacterial infections and the underlying molecular mechanism(s). Taken together, this proposal is designed to elucidate new NTase activity-independent molecular functions of OAS proteins, and to integrate it with antibacterial cellular defense in an innovative functional-model. Upon completion of this study, we will establish a new paradigm of innate host defense orchestrated by OAS proteins that may lead to new therapeutic strategies.

摘要 I型干扰素（IFN）和IFN刺激基因（ISG）提供广泛的抗病毒活性。然而，东道主 IFN和ISG在细菌感染期间提供的保护作用还没有很好地确定。该提案将定义 寡腺苷酸合成酶（OAS）蛋白抗细胞内细菌的新天然免疫功能 感染. OAS是ISG的一个家族，属于进化上古老的核苷酸转移酶家族 （NTase）。OAS蛋白的典型抗病毒机制涉及2 '-5'- 寡聚腺苷酸，引起下游RNase L的激活，导致RNA降解和抑制 蛋白质合成。然而，多种酶活性和失活的OAS的宿主保护功能， 在细菌感染期间的同种型是未知的。本提案将解决这一知识差距， 两种OAS家族蛋白OAS 1和OASL的先天抗菌功能。我们的初步研究表明， 人OAS 1和小鼠直系同源物Oas 1b通过以下方式提供保护，使其免受细胞内细菌感染： 增强几种蛋白质的表达，包括IRF 1，一种主要的抗菌转录因子。 此外，我们发现缺乏OAS家族的另一个成员Oasl 2（人OASL的直系同源物）的小鼠， 对细胞内细菌感染高度敏感，并显示宿主有害的 炎性细胞因子基于这些初步发现，我们假设美洲国家组织的特定成员- 家族蛋白通过独特的NTase活性有助于宿主防御细胞内细菌， 独立的机制。本提案的目的是确定两种OAS的先天抗菌功能 家族蛋白及其潜在机制的三个独立的目标：（1）确定细胞的机制， OAS 1的内在抗菌活性。在这里，我们将定义OAS 1介导的分子机制， 使用体外生物化学和细胞生物学方法的细胞内在抗菌防御。(2)确定输入 Oas 1b在抗细菌先天免疫中的体内作用。我们将使用新生成的Oas 1b基因敲入小鼠模型 鉴定Oas 1b的体内介质和细胞类型特异性抗菌功能。(3)定义OASL的作用 在宿主防御细胞内细菌感染和潜在的分子机制。采取 总之，这一建议旨在阐明新的非NTase活性依赖的OAS分子功能 蛋白质，并将其与创新功能模型中的抗菌细胞防御相结合。完成后 在这项研究中，我们将建立一个由OAS蛋白编排的先天宿主防御的新范式， 导致新的治疗策略。