Inhibition of Candida Virulence and Biofilm Formation by a Bacterial Peptide

项目摘要 口咽念珠菌病（OPC）是口腔疾病的主要病因 包括免疫抑制者（癌症和艾滋病患者）和那些服用广谱抗生素的人。我们 最近鉴定了一种由粪肠球菌产生的肽，其抑制菌丝形态发生， OPC的主要病原体白色念珠菌的生物膜形成。这项研究提出， 该申请试图了解这种肽的成熟形式EntV是如何产生的，它如何靶向C。 白念珠菌菌丝形态发生，以及它对OPC的保护程度，从而填补了一个关键的空白， 我们的知识，并为治疗的发展提供新的途径。其长期目标是 研究旨在开发治疗和预防口咽念珠菌病的新策略。的目标 本申请旨在确定EntV的产生、作用方式和治疗潜力。中央 一种假设是分泌和加工的EntV作用于控制菌丝发育的信号传导途径， C.白色念珠菌导致保护免受念珠菌病。这项研究的基本原理是， EntV抑制C.白色念珠菌将导致新的治疗方法 战略布局通过追求三个目标，将达到本申请的目的。目标1将阐明 生成EntV的活性形式。使用遗传和生化方法，我们将检验以下假设 蛋白酶GelE和/或SprE是切割所需的，二硫键形成由DsbA催化 同源物在目标#2中，C.白色念珠菌是E.粪菌抑制菌丝 将使用细胞生物学和遗传学方法来确定形态发生。根据初步数据， 工作假设是EntV直接与C上几个已知的离散亚结构域之一相互作用。 白念珠菌细胞表面破坏细胞-细胞和细胞-基质粘附，这两者都是生物膜所必需的 阵EntV及其相关肽在预防C.白色念珠菌感染将在 目标3。组织培养细胞（巨噬细胞和口腔上皮细胞）和OPC和 将利用胃肠道定殖。我们假设EntV将保护免受C。白色念珠菌感染， 纳摩尔范围内的念珠菌病。这一贡献的重要性将是了解细菌如何 肽抑制C.白色念珠菌菌丝形态发生，潜在地为治疗设计开辟新途径。 靶向菌丝形态发生作为可能开发新疗法的领域是创新的， 目前的抗真菌剂针对细胞被膜的完整性或生长。这一点的额外好处 研究包括细菌肽生成，真菌形态转换， 微生物之间的相互作用

PROJECT SUMMARY The medical condition oropharyngeal candidiasis (OPC) is a major source of oral morbidity in patient groups including the immunosuppressed (cancer and AIDS patients) and those taking broad-spectrum antibiotics. We recently identified a peptide produced by Enterococcus faecalis that inhibits the hyphal morphogenesis and biofilm formation of the primary causative agent of OPC, Candida albicans. The research proposed in this application seeks to understand how the mature form of this peptide, EntV, is generated, how it targets C. albicans hyphal morphogenesis, and the extent to which it protects against OPC, thereby filling a critical gap in our knowledge and providing new avenues for the development of therapeutics. The long-term goal of this research is to develop novel strategies for treating and preventing oropharyngeal candidiasis. The objective of this application is to determine the generation, mode of action and therapeutic potential of EntV. The central hypothesis is that secreted and processed EntV acts on signaling pathway(s) that controls hyphal development in C. albicans resulting in protection from candidiasis. The rationale for this research is that identification of the mechanism by which EntV inhibits the formation of the invasive form of C. albicans will lead to new treatment strategies. By pursing three aims, the objective of this application will be attained. Aim #1 will elucidate how the active form of EntV is generated. Using both genetic and biochemical approaches, we will test the hypothesis that the proteases GelE and/or SprE are required for cleavage, and disulfide bond formation is catalyzed by a DsbA homolog. In Aim #2, the genes/pathways of C. albicans that are targeted by E. faecalis to inhibit hyphal morphogenesis will be determined using cell biological and genetic approaches. Based on preliminary data, the working hypothesis is that EntV interacts directly with one of several known discrete subdomains on the C. albicans cell surface to disrupt cell-cell and cell-substrate adherence, both of which are essential for biofilm formation. The efficacy of EntV and related peptides in protecting against C. albicans infection will be tested in Aim #3. Tissue culture cells (macrophages and oral epithelial cells) and mouse models of OPC and gastrointestinal colonization will be utilized. We postulate that EntV will protect against C. albicans infection and candidiasis in the nanomolar range. The significance of this contribution will be the knowledge of how a bacterial peptide inhibits C. albicans hyphal morphogenesis, potentially opening new avenues for therapeutic design. Targeting hyphal morphogenesis as an area for the possible development of novel therapeutics is innovative, as current antifungals are directed against the integrity or growth of the cell envelope. Additional benefits of this research include new knowledge in the fields of bacterial peptide generation, fungal morphotype switching, and inter-kingdom microbial interactions.