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致病菌，可引起广谱的急性和慢性疾病 抗生素耐药性是一个日益严峻的挑战，耐甲氧西林金黄色葡萄球菌 (MRSA) 感染是一个日益严峻的挑战。 治疗更加困难，导致患者和医疗系统的负担增加。 大多数平民和军人的皮肤感染都是由这种病原体引起的，但这种病原体如何在皮肤上定殖尚不清楚。 在最近对皮肤外植体的显微镜研究中，金黄色葡萄球菌在皮肤定植期间形成了生物膜群落， 人们发现这些生物膜在 agr 群体感应系统的控制下产生毒力因子。 我们的初步研究发现，缺乏 agr 的 MRSA 菌株在皮肤外植体定植方面表现出显着的缺陷， 在啮齿动物皮肤定植模型中，我们的中心假设是 MRSA 群体感应至关重要。 此外，我们认为群体感应对于皮肤定植和逃避宿主防御至关重要。 在具体目标 1 中，我们将确定群体感染在从皮肤感染到全身感染的转变中的作用。 我们勇敢地说，MRSA 菌株利用 agr 调节因子来进行检测。 为了解决这个假设，我们将比较 MRSA WT 和 Δagr 突变菌株。 我们还将鉴定 agr- 的体外模型并在小鼠皮肤定植模型中进行比较。 最后，确定定植所需的调节因素并确定已知的生物膜因素是否重要。 我们将进行 RNAseq，以更广泛地评估 MRSA 对皮肤的调节功能。 2、我们将确定群体感应对皮肤 MRSA 免疫逃避的贡献。 MRSA 利用 agr 调节因子来逃避皮肤免疫，为此，我们将确定其作用。 群体感应在抗菌肽诱导和耐药中的作用并评估群体感应 我们还将确定 MRSA 脲酶和其他农业物质是否受到调节。 影响 pH 稳态的因素，我们将通过单细胞 RNAseq 评估宿主皮肤反应。 具体目标 3，我们将评估群体感应在定植传播中的功能。 其次，MRSA 群体感应是从皮肤全身传播所必需的。 进一步研究这一机制，我们将确定 MRSA 群体感应功能的要求，并 我们还将对感染进行实时成像。 并确定群体感应对逃避宿主免疫的贡献 更好地了解如何进行。 MRSA 在皮肤上定植并转变为感染，可能为制定治疗策略开辟途径 最大限度地减少皮肤感染负担。