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.

抽象的 I型干扰素（IFN）和IFN刺激基因（ISG）提供广泛的抗病毒活性。但是，主人 细菌感染期间IFN和ISG提供的保护尚未很好地定义。该建议将定义 针对细胞内细菌的寡腺苷酸合成酶（OAS）蛋白的新的先天免疫功能 感染。 Oass是ISG家族，属于进化上古老的核苷酸转移酶家族 （ntase）。 OAS蛋白的规范抗病毒机制涉及2'-5'--的酶促合成 少聚二烯基，导致RNase L下游激活，导致RNA降解和抑制 蛋白质合成。但是，多种酶活性和非活性OA的主机保护功能 细菌感染期间的同工型尚不清楚。该建议将解决此知识差距，以定义 OAS家族蛋白OAS1和OASL的先天抗菌功能。我们的初步研究表明 人的OAS1和小鼠直系同源物，OAS1B，通过通过细胞内细菌的感染保护 增强包括主要抗菌转录因子IRF1在内的几种蛋白质的表达。 此外，我们发现缺乏OASL2的小鼠（人类OASL的直系同源）是OAS家族的另一个成员，是 高度容易受到细胞内细菌感染的影响，并显示出增加的宿主生产 炎症细胞因子。基于这些初步发现，我们假设OAS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的防御 - 独立机制。该提案的目的是确定两个OA的先天抗菌功能 家庭蛋白质和三个独立目标中的基本机制：（1）确定细胞的机制 OAS1的内在抗菌活性。在这里，我们将定义OAS1介导的分子机制 使用体外生化和细胞生物学方法的细胞内在抗菌防御。 （2）确定IN OAS1B在抗细菌先天免疫中的体内作用。我们将使用新生成的OAS1B敲入鼠标模型 确定OAS1B的体内介质和细胞类型的特异性抗菌功能。 （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中。拍摄 总之，该建议旨在阐明OAS的新NTase活性与分子功能 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蛋白质策划的新的先天宿主防御范式，可能 导致新的治疗策略。