Mechanisms of Candida auris skin colonization

摘要 C. auris是一种相对较新的机会性真菌病原体，其以高的内在致病率在全世界传播。 对抗真菌抗生素的抗性和对人类皮肤的强亲和力。它现在被疾病预防控制中心列为顶级 抗药性真菌的威胁流行病学分析表明，病原体的传播发生有效的， 共享住房环境，如医院或疗养院。重要的是，人与人之间的传播 皮肤相关的酵母菌似乎是主要的传播方式。虽然C.耳皮肤定植是 无症状的、危及生命的疾病可能发生在具有其他风险因素的患者中，例如 免疫抑制、静脉导管放置、手术和抗生素。对分子的理解 C.耳内细菌顽强地在皮肤上定植，这可能会提供潜在的机会， 感染周期不幸的是，没有分子被确定为重要的宿主皮肤定植。开始 为了解决这个问题，我们建立了三种皮肤定植和表皮定植的小鼠模型， 白色念珠菌感染，适合于研究念珠菌。耳。使用这些模型，我们观察到 C. auris比C.白色念珠菌。与C. albicans、假丝酵母C.耳不能引起皮肤损伤或 以诱导关键的抗真菌促炎细胞因子IL-17的表达。值得注意的是，C.耳显示群集 表皮中的酵母菌以及毛囊的侵入，这两种情况在C.白色念珠菌中 ~700 C.白念珠菌无效突变体，我们确定了四个基因所需的表皮 皮肤感染。我们破坏了C。使用基于CRISPR/Cas9的方案，在耳直向同源物中进行。我们发现所有 有4个突变株在C.耳。值得注意的是，四个基因中的两个编码C。Auris HOG MAP激酶信号通路的组分的直系同源物，并且是有效皮肤所必需的。 三种模式下的殖民化。这些数据使我们假设HOG MAPK信号通路 控制C.通过控制下游靶基因的表达，我们假设 这些靶基因中的一个或多个将参与促进C.耳有效地殖民 皮肤我们将通过以下方法来检验这个高风险/高回报假设：1）研究C。耳Hog 1 在皮肤定殖途径中的作用，并确定其在基因调控中的作用; Auris 皮肤定植这些研究有可能确定C. Auris 定植在皮肤上，这是这种重要的新出现的耐药病原体感染周期的一个中心方面。 在奠定了基础之后，我们有能力实现这些目标，我们预计这些目标将 为开始获得对C.耳。

ABSTRACT C. auris is a relatively new opportunistic fungal pathogen that is spreading worldwide with high rates of intrinsic resistance to antifungal antibiotics and a strong affinity for human skin. It is now ranked by the CDC as the top drug-resistant fungal threat. Epidemiological analysis suggests that pathogen transmission occurs efficiently in shared housing environments such as hospitals or nursing homes. Importantly, person-to-person transmission of skin-associated yeasts appears to be a primary mode of spread. Although C. auris skin colonization is asymptomatic, life-threatening disease can arise in patients with additional risk factors, such as immunosuppression, intravenous catheter placement, surgery, and antibiotics. Understanding of the molecular mechanisms by which C. auris tenaciously colonizes the skin might offer potential opportunities to interrupt the infection cycle. Unfortunately, no molecules been identified that are important for host skin colonization. To begin to address this problem, we have established three mouse models of skin colonization and epicutaneous infection with Candida albicans that are suitable for investigations of C. auris. Using these models, we observe significantly higher titers of C. auris than C. albicans. Unlike C. albicans, C. auris fails to induce skin damage or to induce expression of the key antifungal pro-inflammatory cytokine, IL-17. Notably, C. auris displays clusters of yeast in the epidermis as well as invasion of the hair follicles, neither of which are seen with C. albicans. In a forward genetic screen of ~700 C. albicans null mutants, we identified four genes required for epicutaneous infection of skin. We disrupted the C. auris orthologs using a CRISPR/Cas9-based protocol. We found that all four mutant displayed defects in skin colonization in C. auris. Notably, two of the four genes encode C. auris orthologs of components of the HOG MAP kinase signaling pathway and are required for effective skin colonization in all three models. These data lead us to hypothesize that the HOG MAPK signaling pathway controls skin colonization in C. auris by controlling the expression of downstream target genes. We hypothesize that one or more of these target genes will be involved in promoting the ability of C. auris to effectively colonize the skin. We will test this high-risk/high-payoff hypothesis by 1) Investigating the role of the C. auris Hog1 pathway in skin colonization and establishing its role in gene regulation and 2) Identifying effectors of C. auris skin colonization. These studies have the potential to identify molecules and mechanisms required for C. auris to colonize the skin, a central aspect of the infection cycle of this important emerging drug-resistant pathogen. Having laid the groundwork, we are in a strong position to accomplish these goals, which we anticipate will provide a foundation to begin to obtain molecular insights into the unique biology of C. auris.