Bacterial anti-inflammatory lipid mediators

细菌抗炎脂质介质

基本信息

批准号：
10350479
负责人：
Christopher David Radka
金额：
$ 10万
依托单位：
ST. JUDE CHILDREN'S RESEARCH HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-02-17 至 2024-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10350479
关键词：
Address Anti-Bacterial Agents Anti-Inflammatory Agents Area Arrestins Attenuated Bacteria Bacterial Infections Bifidobacterium Binding Biochemical Biochemistry Biological Assay CD1 Antigens Cell Culture Techniques Cells Complement Coupled Cryoelectron Microscopy Encapsulated Environment Enzymes Fatty Acids Flow Cytometry Foundations G Protein-Coupled Receptor Signaling G-Protein-Coupled Receptors Genetic Transcription Goals Homologous Gene Hydration status Immune Immune Evasion Immune response Immune signaling Immunologics Immunologist Immunology Immunosuppression Infection Inflammation Inflammatory Response Innate Immune Response Innate Immune System Instruction Intercept Intestines Invaded Investigation Knock-out Laboratories Lead Life Ligand Binding Lipids Lipopolysaccharides Lipoproteins Luciferases Mammalian Cell Measures Mediating Mediator of activation protein Membrane Mentors Modeling Modification Molecular Molecular Conformation Mus Oleates Organism Pathogen detection Pathogenesis Pathogenicity Pathway interactions Pattern Peroxisome Proliferator-Activated Receptors Pertussis Toxin Phase Phospholipids Play Receptor Activation Receptor Cell Receptor Signaling Reporter Reporting Research Roentgen Rays Role Signal Pathway Signal Transduction Signaling Molecule Site Skin Tissue Soft Tissue Infections Staphylococcus aureus Structure Symbiosis System T cell response T-Cell Activation T-Cell Receptor TLR2 gene Techniques Testing Tissues Toll-like receptors Training Unsaturated Fatty Acids Vesicle Virulence antimicrobial drug biophysical techniques career commensal bacteria cytokine design drug discovery experimental study extracellular extracellular vesicles gastrointestinal gut inflammation gut microbiome human pathogen hydroxy fatty acid immunoregulation inhibitor interest lipid mediator lipid metabolism multidisciplinary novel pathogen pathogenic bacteria pi bond programs receptor receptor binding recruit response structural biology vesicular release

项目摘要

Project Summary The rapid response of the innate immune system to infections relies on the detection of pathogen-associated molecular patterns (PAMPs), such as lipopolysaccharides, that activate a robust inflammatory response to invading organisms. My research program focuses on an unappreciated countermeasure deployed by commensal bacteria and pathogens that attenuates the immune response to PAMPs. Oleate hydratase (OhyA) is an enzyme that is expressed in commensal bacteria and the important human pathogen Staphylococcus aureus. OhyA stereospecifically hydrates the 9-cis double bond of unsaturated fatty acids to produce 10- hydroxy-fatty acids (hFAs); however, bacteria expressing OhyA do not synthesize unsaturated fatty acids. OhyA substrates are only encountered at the interface of host tissues, where unsaturated fatty acids are abundant. I hypothesize that hFAs produced by commensal or pathogenic organisms serve as signaling molecules that blunt the innate immune response to PAMPs. Indeed, S. aureus ohyA knockouts fail to establish infections in mice, illustrating the importance of OhyA and hFAs to S. aureus virulence. Thus, hFAs, which were first discovered in the gut microbiome, may provide an important mechanism for commensal bacteria to attenuate gastrointestinal inflammation and create tolerant, symbiotic environments. My pilot experiments and some previous reports provide preliminary evidence for the anti-inflammatory action of hFAs, but the mechanism(s) of immune suppression by hFAs are unknown. To address this shortcoming, I will receive formal immunology instruction through coursework and hands-on training in the laboratory of Dr. Paul Thomas, an expert immunologist, during the K99 phase. We will determine whether hFAs directly antagonize extracellular PAMP binding to immune cell receptors, bind to CD1 lipid-presenting molecules for T-cell receptor recognition to antagonize T cell activation, or intercept signaling downstream of PAMP-receptor activation by stimulating G-protein coupled receptors and/or PAPR. The results of these experiments will uncover the mechanistic basis for hFA modification of immune cell responses. OhyA has no mammalian homolog, and validating the importance of OhyA for virulence coupled with the X-ray structures of OhyA will provide the key information required to determine whether OhyA is a candidate target for antimicrobial drug discovery. During the R00 phase, I will test the hypothesis that OhyA is packaged into extracellular vesicles released by S. aureus to interact with surrounding host tissues to form a halo of hFA mediators around the infection site. My findings will provide an atomistic mechanistic understanding of how OhyA binds to and influences membrane structure to promote vesicle formation. The K99/R00 research plan is designed to leverage my expertise in biochemistry and structural biology, while receiving new training in immunology, to advance the understanding of immune regulation by bacteria and launch a productive and successful career in which I will lead a research program to elucidate the role bacteria lipid products play in controlling host responses.

项目摘要先天免疫系统对感染的快速反应依赖于病原体相关的检测分子模式（小型），例如脂多糖，激活对入侵生物。我的研究计划着重于由共生细菌和病原体可减弱对弹药的免疫冲突。 Oleate Hydrotase（OHYA）是在共生细菌和重要人类病原体葡萄球菌中表达的酶金黄色葡萄酒。 Ohya立体特定水合不饱和脂肪酸的9-CIS双键产生10- 羟基脂肪酸（HFA）；但是，表达OHYA的细菌不合成不饱和脂肪酸。 Ohya底物仅在宿主组织的界面遇到，那里不饱和脂肪酸是丰富。我假设由共生或致病生物产生的HFA用作信号钝化了对小型弹药的先天免疫反应的分子。确实，金黄色葡萄球菌Ohya淘汰赛无法在小鼠中建立感染，说明了Ohya和HFAS对金黄色葡萄球菌病毒的重要性。那，hfas，这是在肠道微生物组中最初发现的，这可能提供了一个重要机制细菌减弱胃肠道感染并产生耐受性共生环境。我的飞行员实验和一些以前的报告为HFA的抗炎作用提供了初步证据，但是HFA的免疫抑制机制尚不清楚。为了解决这个缺点，我将保罗博士通过课程和实践培训接受正式的免疫学指导在K99阶段，托马斯（Thomas），专家免疫学家。我们将确定HFA是否直接拮抗细胞外性能与免疫细胞受体结合，与CD1脂质呈递分子结合T细胞受体识别与T细胞激活的拮抗或通过刺激G蛋白耦合受体和/或PAPR。这些实验的结果将发现 HFA修饰免疫细胞反应的机械基础。 Ohya没有哺乳动物同源物，验证Ohya对病毒的重要性以及Ohya的X射线结构将提供钥匙确定OHYA是否是抗菌药物发现的候选靶标的信息。期间 R00阶段，我将检验以下假设，即OHYA被包装成S. S. 金黄色葡萄球菌与周围的宿主组织相互作用，形成感染部位周围HFA介质的光环。我的调查结果将对Ohya如何与膜结合并影响膜有原子的机械理解促进囊泡形成的结构。 K99/R00研究计划旨在利用我的专业知识在接受免疫学培训的同时，生物化学和结构生物学，以促进理解通过细菌进行免疫调节，并创造了一项富有成效而成功的职业，我将领导一项研究阐明细菌脂质产品在控制宿主反应中起作用的作用的程序。