Investigating the role of Staphylococcus aureus strain-level diversity on neutrophil recruitment and wound healing in a cutaneous leishmaniasis infection

项目总结 皮肤利什曼病是一种寄生性感染，引起的疾病范围从 从单一的自我修复损伤到毁容的慢性损伤，尽管接受了治疗，但仍无法愈合。而这些因素 驾驶损伤的慢性化程度尚不清楚，很明显，许多最严重的疾病都是由 由于不受控制的炎症，而不是高寄生虫负担。在小鼠中，慢性利什曼病皮损是 特点是中性粒细胞聚集增加，炎性细胞因子持续激活，以及 免疫细胞向病变部位的渗透增加，所有这些都会加剧组织损伤并延迟愈合。 我们的实验室以前已经证明，在皮肤上定植的微生物对小鼠的免疫病理学有贡献 然而，皮肤微生物区系在调节病变愈合中的作用尚不清楚。我们发现， 人类皮肤利什曼病皮损最常见的定植细菌是金黄色葡萄球菌(S. 金黄色葡萄球菌)，在许多不同的病理中以一种特定的应变方式延迟伤口愈合，是一种有效的 中性粒细胞招募人员。我们也已经能够证明从人类培养的金黄色葡萄球菌临床分离株 皮肤利什曼病皮损诱导分泌不同数量的中性粒细胞趋化因子，如 伤口环境中上皮细胞的白介素8(IL-8)。因此，我的提议的中心假设是 金黄色葡萄球菌通过变种中性粒细胞募集和修复延迟皮肤利什曼病皮损愈合 积累。在目标1中，我将确定金黄色葡萄球菌介导的中性粒细胞募集的菌株特异性效应。 创伤模型和皮肤利什曼病模型中伤口愈合和免疫病理学的研究 使用LysM-EGFP小鼠。在目标2中，我将确定金黄色葡萄球菌中性粒细胞招募和持久性的不同之处 使用全基因组测序和比较基因组学研究临床分离株的基因 人类皮肤利什曼病皮损的临床结果和RNA测序基因表达的数据。 这些发现将共同推动对金黄色葡萄球菌感染的菌株特异性影响的理解和 中性粒细胞在伤口愈合中的重新募集，发现可用于预测患者预后的生物标记物，以及 寻找治疗皮肤利什曼病的新靶点。

PROJECT SUMMARY Cutaneous leishmaniasis is a parasitic infection that causes a variable spectrum of disease ranging from single, self-healing lesions to disfiguring chronic lesions that do not heal despite treatment. While the factors driving lesion chronicity are not clear, it is evident that many of the most severe forms of the disease are caused by uncontrolled inflammation rather than high parasite burden. In mice, chronic leishmaniasis lesions are characterized by increased neutrophil accumulation, persistent activation of inflammatory cytokines, and increased infiltration of immune cells to the lesion site, all of which exacerbate tissue damage and delay healing. Our lab has previously shown that colonizing microbes on the skin contribute to immunopathology in murine models, however the role of the skin microbiota in regulating lesion healing is not known. We have found that the most common bacteria colonizing human cutaneous leishmania lesions is Staphylococcus aureus (S. aureus) which delays wound healing in a strain-specific manner across many different pathologies and is a potent neutrophil recruiter. We have also been able to show that S. aureus clinical isolates cultured from human cutaneous leishmaniasis lesions induce secretion of different amounts of neutrophil chemotactic factors such as interleukin-8 (IL-8) by epithelial cells in a wound setting. Therefore, the central hypothesis of my proposal is that S. aureus delays cutaneous leishmaniasis lesion healing through strain-variable neutrophil recruitment and accumulation. In Aim 1, I will determine the strain-specific effect of S. aureus-mediated neutrophil recruitment on wound healing and immunopathology in both a wounding model and in a cutaneous leishmaniasis model using LysM-EGFP mice. In Aim 2, I will identify differences S. aureus neutrophil recruitment and persistence genes across clinical isolates using whole genome sequencing and comparative genomics and associate this data with clinical outcomes and RNA sequencing gene expression from human cutaneous leishmaniasis lesions. These findings will collectively drive understanding of the strain-specific effects of S. aureus infection and neutrophil recruitment on wound healing, uncover biomarkers that can be used to predict patient outcome, and identify novel therapeutic targets in the treatment of cutaneous leishmaniasis.