Mechanisms of skin commensal colonization resistance against opportunistic Staphylococci

项目总结 最近的研究强调了共生凝固酶阴性葡萄球菌(CONS)的丰富 健康的皮肤。有证据表明，CONS主动塑造皮肤免疫和微生物环境，以抵抗 包括金黄色葡萄球菌在内的机会性病原体在各种 这些机制统称为殖民抵抗。最常见的孤立的和最有特点的 来自人类皮肤的假单胞菌是表皮葡萄球菌。鉴于它在皮肤上的相对丰富，它是 毫不奇怪，表皮葡萄球菌在历史上一直被用于被认为代表所有 反对意见。然而，对定植抗性的研究值得对其他皮肤疾病进行更广泛的解剖， 尤其是考虑到表皮葡萄球菌是一种机会性的病原体，也是医疗植入的主要原因- 相关感染。尤其令人感兴趣的是第二种最常见的致病菌--葡萄球菌 人类。虽然与表皮葡萄球菌相比，研究相对较少，但目前的证据表明，人葡萄球菌可能 在维持皮肤动态平衡和定植方面扮演一个被低估但却很重要的角色 抵抗。人类链球菌制造多种抗病原体抗生素，我们的初步研究结果表明，S。 人类不包含表皮葡萄球菌可以用来降解皮肤屏障的致病基因。 这项建议旨在填补我们在理解特定囚犯在 通过确定人链球菌皮肤定植抗性的机制来维持皮肤健康。 一种潜在的侵染抗性机制是辅助基因调节(AGR)仲裁 感应系统，这是普遍存在于葡萄球菌。这两个成分系统对它的同源词作出反应 自身诱导肽(AIP)信号。在金黄色葡萄球菌中，agr调节一系列毒力因子的表达。 对于有效的皮肤感染是必要的。一些，但不是所有的罪犯制造AIP，抑制金黄色葡萄球菌和 重要的是，并不是所有的表皮葡萄球菌AIP都抑制金黄色葡萄球菌的agr信号，这表明其他cons也可能抑制。 有助于串扰和殖民抵抗。我们的合作者表明，人链球菌至少制造了 一种金黄色葡萄球菌群体感应的AIP抑制剂。通过对健康皮肤人葡萄球菌废液的分析 菌株，我确定人链球菌至少产生六种AIP变异体，既能抑制金黄色葡萄球菌，又能抑制S。 表皮细胞群体感应。根据这些初步数据和临床观察，我假设S。 人及其农业调节因子保护宿主皮肤免受机会性葡萄球菌的攻击 病原体。为了解决这一假设，我提出了两个创新的具体目标：(1)描述每个S。 人的AIP类型和在种间和种内串扰中的功能，以及(2)决定人的链球菌如何 定植和agr调节因子刺激人体皮肤形成保护性的抗病原体环境。 总而言之，这项提案将是第一个对殖民抵抗提供机械性见解的提案 一种普遍存在但未被充分研究的正常人类植物群的机制及其潜在的应用 一种治疗皮肤病的新型益生菌或治疗剂。

PROJECT SUMMARY Recent studies highlight the abundance of commensal coagulase-negative staphylococci (CoNS) on healthy skin. Evidence suggests that CoNS actively shape the skin immunological and microbial milieu to resist colonization or infection by opportunistic pathogens, including Staphylococcus aureus, in a variety of mechanisms collectively termed colonization resistance. The most frequently isolated and best characterized CoNS from human skin is Staphylococcus epidermidis. Given its relative abundance on the skin, it is unsurprising that S. epidermidis has historically been used for studies assumed to be representative of all CoNS. However, investigation of colonization resistance merits a wider dissection of other skin CoNS, especially given that S. epidermidis is an opportunistic pathogen and the leading cause of medical implant- associated infections. Of particular interest is the second most frequently isolated CoNS, Staphylococcus hominis. While relatively unstudied compared to S. epidermidis, current evidence suggests that S. hominis may be an underappreciated yet important player in maintaining cutaneous homeostasis and colonization resistance. S. hominis makes multiple anti-pathogen lantibiotics and our preliminary findings suggest S. hominis does not contain the same pathogenic genes that S. epidermidis can use to degrade the skin barrier. This proposal seeks to fill a significant gap in in our understanding of the multifaceted roles of specific CoNS in maintaining skin health by determining mechanisms of S. hominis skin colonization resistance. One potential colonization resistance mechanism is the Accessory Gene Regulator (agr) quorum sensing system, which is ubiquitous among staphylococci. This two component system responds to its cognate auto-inducing peptide (AIP) signal. In S. aureus, agr regulates the expression of a suite of virulence factors necessary for productive skin infection. Some, but not all CoNS make AIPs that inhibit S. aureus agr and importantly, not all S. epidermidis AIPs inhibit S. aureus agr signaling suggesting that other CoNS may also contribute to crosstalk and colonization resistance. Our collaborators showed that S. hominis makes at least one AIP inhibitor of S. aureus quorum sensing. Through analysis of spent media from healthy skin S. hominis strains, I determined that S. hominis makes at least six AIP variants that inhibit both S. aureus and S. epidermidis agr quorum sensing. With these preliminary data and clinical observations, I hypothesize that S. hominis and its agr-regulated factors protect host skin from challenge by opportunistic staphylococcal pathogens. To address this hypothesis, I propose two innovative specific aims to (1) characterize each S. hominis AIP type and function in inter- and intraspecies crosstalk, and (2) determine how S. hominis colonization and agr-regulated factors stimulate a protective anti-pathogen environment on human skin. Together, this proposal will be the first to provide mechanistic insight into the colonization resistance mechanisms of a ubiquitous, yet understudied member of the normal human flora with potential applications as a novel probiotic or therapeutic for skin diseases.