Staphylococcus aureus induced itch and neuro-immune signaling in skin infections

金黄色葡萄球菌在皮肤感染中引起瘙痒和神经免疫信号传导

基本信息

批准号：
10707178
负责人：
Isaac Ming-Cheng Chiu
金额：
$ 73.54万
依托单位：
HARVARD MEDICAL SCHOOL
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：
2022-09-19 至 2027-07-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10707178
关键词：
Ablation Afferent Neurons Affinity Atopic Dermatitis Automobile Driving Behavior Binding Biochemical Biological Biological Assay Calcium Cells Cheek structure Complement Data Detection Disease Enzyme-Linked Immunosorbent Assay Esthesia Family G-Protein-Coupled Receptors Genetic Goals Human Image Immune Immune response Immunologics Impetigo Infection Infectious Skin Diseases Inflammation Inflammation Mediators Lesion Link Measures Mediating Mediator Microbe Modeling Molecular Molecular Target Mus Nerve Nervous System Neurobiology Neuroimmune Neurons PAR-1 Receptor Pain Pathogenesis Pathology Patients Peptide Hydrolases Play Production Proteinase-Activated Receptors Proteomics Pruritus Recombinants Role Serine Protease Signal Transduction Site Skin Small Interfering RNA Spinal Ganglia Staphylococcus aureus Staphylococcus aureus infection Symptoms TRPV1 gene Therapeutic Touch sensation Virulence Factors Work antagonist chronic itch cytokine extracellular genetic approach glutamyl endopeptidase host-microbe interactions immunoregulation intradermal injection knock-down luminescence microbial mutant neural neurobehavioral neurotransmission neutrophil novel pain behavior pathogenic bacteria pharmacologic proteinase In receptor response skills skin barrier skin damage skin disorder skin lesion subcutaneous

项目摘要

PROJECT SUMMARY Itch is an unpleasant sensation that evokes a desire to scratch. While itch accompanies many skin infections, a causative role for microbes in itch has not been previously investigated. Itch-induced scratching can contribute to significant skin damage and bacterial pathogenesis. Here, we investigate the role of the human bacterial pathogen Staphylococcus aureus and its secreted proteases in driving itch and inflammation. S. aureus colonizes 90% of skin lesions caused by Atopic Dermatitis, a disease characterized by chronic itch. S. aureus also causes impetigo, a contagious skin disease characterized by itchy lesions. We hypothesize that S. aureus secretes proteases that can directly act on host sensory neurons to drive itch, scratch-induced skin damage, and neuroimmune crosstalk. Our preliminary data shows that S. aureus epicutaneous infection of mice induces robust itch behaviors (alloknesis, spontaneous itch) and resulting skin pathology. Using isogenic mutant strains, we find that secreted S. aureus proteases, and in particular the serine protease V8 (SspA) is required for itch production during infection. In Specific Aim 1, we will determine the role of S. aureus V8 protease in driving itch, neuronal activation, and skin inflammation. We will utilize isogenic S. aureus mutant and complemented strains for V8, as well as recombinant V8 to elucidate the necessity and sufficiency of this protease in inducing itch, scratch induced damage, and inflammation caused by S. aureus. Itch is mediated by dorsal root ganglia (DRG) sensory neurons. DRG neuron calcium imaging will be performed to investigate specific neuronal responses to V8 protease. Cheek intradermal injections and neurobehavioral analysis will be performed to distinguish itch vs. pain behaviors in mice. In Specific Aim 2, we will determine whether neurons and host cells detect S. aureus V8 protease through specific protease-activated receptors (PARs). Preliminary data indicates that PAR1 may be an important host receptor that is activated by V8. We will utilize biochemical and luminescence-based approaches to determine the V8 cleavage site on PAR1. We will treat mice with pharmacological antagonists against PAR1 and utilize PAR1-/- mice to determine effects on V8-protease and S. aureus induced itch. In Specific Aim 3, we will utilize genetic approaches to ablate specific skin-innervating neurons (Nav1.8+, Mrgprd+, and Trpv1+) to assay their roles in S. aureus induced inflammation. We hypothesize that neurons will drive both itch/scratch-induced damage, and the release of neural mediators that directly signal to immune cells. We will use targeted approaches and proteomics to assess neuronal release of proinflammatory mediators. Our work could elucidate novel molecular crosstalk between S. aureus, host neurons and immune cells in itch. The three aims of this study leverage the complementary skills of Dr. Chiu and Dr. Horswill, combining neurobiological, immunological, and microbiological approaches to investigate the mechanisms of itch and neuroimmune signaling in S. aureus infection. Given the importance of itch in skin diseases, elucidating a microbial role in inducing this sensation could transform our understanding of host-microbe interactions at the skin barrier.

项目概要瘙痒是一种不愉快的感觉，会引起抓挠的欲望。虽然许多皮肤感染都会伴随瘙痒，但此前尚未研究过微生物在瘙痒中的致病作用。瘙痒引起的抓挠可能会导致严重的皮肤损伤和细菌发病机制。在这里，我们研究人类细菌的作用病原体金黄色葡萄球菌及其分泌的蛋白酶可引起瘙痒和炎症。金黄色葡萄球菌 90% 的特应性皮炎（一种以慢性瘙痒为特征的疾病）引起的皮肤损伤都有定植。金黄色葡萄球菌还会引起脓疱病，这是一种以瘙痒皮损为特征的传染性皮肤病。我们假设金黄色葡萄球菌分泌可以直接作用于宿主感觉神经元的蛋白酶，以引起瘙痒、抓伤引起的皮肤损伤，以及神经免疫串扰。我们的初步数据表明，小鼠的金黄色葡萄球菌表皮感染可诱导强烈的瘙痒行为（异动、自发瘙痒）和由此产生的皮肤病理学。使用同基因突变株，我们发现分泌的金黄色葡萄球菌蛋白酶，特别是丝氨酸蛋白酶 V8 (SspA) 是瘙痒所必需的感染期间的生产。在具体目标 1 中，我们将确定金黄色葡萄球菌 V8 蛋白酶在驱痒中的作用，神经元激活和皮肤炎症。我们将利用同基因金黄色葡萄球菌突变体和互补菌株对于V8以及重组V8来阐明该蛋白酶诱导瘙痒的必要性和充分性，抓伤引起的损伤，以及金黄色葡萄球菌引起的炎症。瘙痒由背根神经节 (DRG) 介导感觉神经元。将进行 DRG 神经元钙成像以研究特定神经元反应 V8 蛋白酶。将进行面颊皮内注射和神经行为分析，以区分瘙痒与瘙痒。小鼠的疼痛行为。在具体目标 2 中，我们将确定神经元和宿主细胞是否检测到金黄色葡萄球菌 V8 蛋白酶通过特定的蛋白酶激活受体 (PAR)。初步数据表明 PAR1 可能是一种由 V8 激活的重要宿主受体。我们将利用基于生化和发光的确定 PAR1 上 V8 切割位点的方法。我们将用药物拮抗剂治疗小鼠对抗 PAR1 并利用 PAR1-/- 小鼠来确定对 V8-蛋白酶和金黄色葡萄球菌引起的瘙痒的影响。在具体目标 3，我们将利用遗传方法来消融特定的皮肤支配神经元（Nav1.8+、Mrgprd+、和 Trpv1+）来测定它们在金黄色葡萄球菌诱导的炎症中的作用。我们假设神经元将驱动两者瘙痒/抓伤引起的损伤，以及直接向免疫细胞发出信号的神经介质的释放。我们将使用靶向方法和蛋白质组学来评估促炎介质的神经元释放。我们的工作可以阐明金黄色葡萄球菌、宿主神经元和瘙痒免疫细胞之间的新型分子串扰。三个这项研究的目的是利用 Chiu 博士和 Horswill 博士的互补技能，结合神经生物学、免疫学和微生物学方法来研究瘙痒和神经免疫机制金黄色葡萄球菌感染中的信号传导。鉴于瘙痒在皮肤病中的重要性，阐明微生物在皮肤病中的作用诱发这种感觉可以改变我们对皮肤屏障上宿主与微生物相互作用的理解。