Quorum Sensing Dependent Interactions with Biofilms and Innate Immunity Defenses

群体感应与生物膜和先天免疫防御的相互作用

• 批准号: 9780343
• 负责人: ALEXANDER R HORSWILL
• 金额: --
• 依托单位: VA EASTERN COLORADO HEALTH CARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2023-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9780343
• 关键词: Address; Adherence; Adult; Antibiotic Resistance; Antimicrobial Resistance; Biology; Blood Circulation; Cells; Clinical; Communities; Defect; Desiccation; Development; Disease; Distal; Environment; Genus staphylococcus; Healthcare Systems; Hospitalization; Host Defense; Human; Image; Immune; Immune Evasion; Immune response; Immunity; Infection; Infectious Skin Diseases; Kinetics; Life Style; Lipids; Medical; Methicillin; Microbial Biofilms; Microscopy; Military Personnel; Modeling; Molecular Genetics; Monitor; Mus; Nasal cavity; Natural Immunity; Outpatients; Patients; Play; Population; Research Personnel; Resistance; Risk Factors; Rodent; Role; Site; Skin; Skin Tissue; Skin colonization; Soft Tissue Infections; Staphylococcus aureus; Staphylococcus aureus infection; Structure; System; Systemic infection; Therapeutic; Unsaturated Fatty Acids; Urease; Veterans; Virulence Factors; acute infection; antimicrobial peptide; chronic infection; commensal microbes; defense response; improved; in vitro Model; infection burden; infection risk; insight; methicillin resistant Staphylococcus aureus; mutant; pH Homeostasis; pathogen; prevent; quorum sensing; real-time images; response; service member; single-cell RNA sequencing; transcriptome sequencing

Staphylococcus aureus is an opportunistic pathogen that causes a broad spectrum of acute and chronic infections. Antibiotic resistance is a growing challenge and methicillin-resistant S. aureus (MRSA) infections are more difficult to treat, resulting in increased burden for both patients and healthcare systems. S. aureus causes the majority of skin infections in civilians and the military, but how this pathogen colonizes the skin is unknown. In recent microscopy studies on skin explants, S. aureus developed biofilm communities during skin colonization, and these biofilms were found to produce virulence factors under control of the agr quorum-sensing system. In our preliminary studies, we found that MRSA strains lacking agr show striking defects in skin explant colonization, and in rodent skin colonization models. Our central hypothesis is that MRSA quorum-sensing is essential for skin colonization and evasion of host defenses. Additionally, we believe quorum-sensing plays a critical role in the transition from skin to systemic infection. In Specific Aim 1, we will determine the role of quorum- sensing during MRSA skin colonization. We hypothesize that MRSA strains use agr-regulated factors to colonize the skin. To address this hypothesis, we will compare MRSA WT and ∆agr mutant strains using in vitro models of adherence and compare them in a mouse skin colonization model. We will also identify agr- regulated factors required for colonization and determine whether known biofilm factors are important. Lastly, we will perform RNAseq to obtain a broader assessment of MRSA regulated functions on skin. In Specific Aim 2, we will determine the contribution of quorum-sensing to MRSA immune evasion on the skin. We hypothesize that MRSA evades skin immunity using agr-regulated factors. Toward this end, we will determine the role of quorum-sensing in the induction and resistance to antimicrobial peptides and assess the quorum-sensing response to skin unsaturated fatty acids. We will also determine whether MRSA urease and other agr-regulated factors contribute to pH homeostasis, and we will evaluate the host skin response by single-cell RNAseq. In Specific Aim 3, we will assess the function of quorum-sensing in dissemination from colonization. We hypothesize that the MRSA quorum-sensing is required for systemic dissemination from the skin. To further investigate this mechanism, we will determine the requirement for MRSA quorum-sensing function and agr-regulated factors in skin dissemination to distal sites. We will also perform real-time imaging of infections and determine the quorum-sensing contribution to evasion of host immunity. An improved understanding of how MRSA colonizes the skin and transitions to infection could open avenues to developing therapeutic strategies for minimizing the skin infection burden.

金黄色葡萄球菌是一种机会性病原体，可引起急性和慢性频谱 感染。抗生素抗性是一项日益严格的挑战，耐甲氧西林的金黄色葡萄球菌（MRSA）感染是 更难治疗，导致患者和医疗保健系统的燃烧增加。 S.金黄色葡萄球菌的原因 平民和军队中的大多数皮肤感染，但是这种病原体如何在皮肤上殖民是未知的。 在对皮肤外植体的最近显微镜研究中，金黄色葡萄球菌在皮肤定植期间发展了生物膜群落， 并且发现这些生物膜会在控制农业群体感应系统的控制下产生病毒因子。在 我们的初步研究，我们发现缺乏AGR的MRSA菌株在皮肤外植体中表现出明显的缺陷， 在啮齿动物皮肤定植模型中。我们的核心假设是MRSA Quorum-Sensing是必不可少的 用于皮肤定植和宿主防御的演变。此外，我们认为法定感应效果至关重要 在从皮肤到全身感染的过渡中的作用。在特定目标1中，我们将确定法定人数的作用 在MRSA皮肤定植期间感测。我们假设MRSA菌株使用协议调节的因素 殖民皮肤。为了解决这一假设，我们将使用IN比较MRSA WT和∆Agr突变菌株 体外依从性模型并在小鼠皮肤定植模型中进行比较。我们还将确定Agr- 定植所需的调节因素，并确定已知的生物膜因子是否重要。最后， 我们将执行RNASEQ，以更广泛地评估MRSA对皮肤的调节功能。在特定目标中 2，我们将确定群体感应对MRSA免疫远程对皮肤的贡献。我们假设 MRSA使用协议调节的因素来逃避皮肤免疫力。为此，我们将确定角色 在诱导和对抗菌胡椒的抗性和抗性中的群体感应和评估群体感应的 对皮肤不饱和脂肪酸的反应。我们还将确定MRSA尿素和其他协议是否受到调查 因素有助于pH稳态，我们将通过单细胞RNASEQ评估宿主皮肤反应。在 具体的目标3，我们将评估法定人数在传播定植中的功能。我们 假设MRSA群体感应是从皮肤中进行全身传播的。到 进一步研究这种机制，我们将确定MRSA Quorum-Sensing函数和 AGR调节的皮肤传播到远端部位的因素。我们还将对感染进行实时成像 并确定对宿主免疫进化的群体感应贡献。对如何改善了如何理解 MRSA在皮肤和感染过渡时都可以开放制定治疗策略的途径 为了最大程度地减少皮肤感染。