In vivo-induction of Candida albicans morphogenesis

描述（由申请方提供）：白色念珠菌是人类的主要真菌病原体，是发病和死亡的重要原因，尤其是在免疫功能低下的宿主中。与大多数病原体不同，C.白色念珠菌能够感染身体内的几乎每个解剖部位，并且在温血动物之外没有已知的宿主。在单细胞（酵母）和丝状形式之间可逆转换的能力显著有助于入侵和致病过程。因此，有一个很大的推动力，以了解信号和调控途径，管理酵母丝酵母开关。然而，大多数检查该过程的研究都是在体外使用试图模拟宿主样刺激的条件进行的。我们实验室最近的研究表明，“菌丝缺陷”突变体在体外“锁定”在酵母生长模式中，能够在体内侵入粘膜组织期间形成丝状体。其他数据表明，形态发生是由特定组织部位的宿主来源信号触发的。此外，这些信号激活在体外沉默的形态发生途径。基于这些观察，我们假设C。白色念珠菌具有响应于体内粘膜细胞接触而刺激丝状生长的宿主环境感应机制。在这个R21计划中，我们将使用新兴技术来研究C.白念珠菌细胞感染粘膜组织在体内，并确定与宿主诱导的形态发生相关的基因。我们建议：1）识别C。在体内宿主-病原体相互作用期间表达的白色念珠菌基因; 2）鉴定C.在粘膜诱导的形态发生期间特异性表达的白念珠菌基因; 3）验证全局表达数据集，以及4）评估敲除菌株在体外和体内经历形态发生的能力。据我们所知，这一建议将是第一个：1）确定转录签名的C。白念珠菌细胞在体内粘膜表面，和2）阐明新的分子靶点和途径，是独立的主要体外形态调控。这些研究将产生重要的见解，了解宿主-真菌病原体的相互作用，并允许开发新的抗真菌策略，针对形态发生和侵入过程。公共卫生相关性我们的研究结果将通过确定可能用于预防和治疗干预的毒力因子来影响当前的治疗策略。这些知识应该会加速我们诊断、治疗和控制人类头号真菌病原体的能力。

DESCRIPTION (provided by applicant): Candida albicans is the major fungal pathogen of humans, and is a significant cause of morbidity and mortality especially in immunocompromised hosts. Unlike most pathogens, C. albicans is capable of infecting virtually every anatomical site within the body and has no known reservoir outside of warm-blooded animals. The ability to reversibly switch between the unicellular (yeast) and filamentous form contributes significantly to the invasion and pathogenic process. Thus, there is a great impetus to understand the signals and regulatory pathways that govern the yeast-filament-yeast switch. The majority of studies examining this process, however, have been performed in vitro using conditions that attempt to mimic host-like stimuli. Recent studies in our laboratory have shown that `hyphal defective' mutants `locked' in the yeast mode of growth in vitro are capable of forming filaments during invasion of mucosal tissue in vivo. Additional data suggests that morphogenesis is triggered by host-derived signals at specific tissue sites. Furthermore, these signals activate a morphogenetic pathway that is silent in vitro. Based on these observations, we HYPOTHESIZE that C. albicans possesses a host environment-sensing mechanism that stimulates filamentous growth in response to in vivo mucosal cell contact. In this R21 proposal, we will use emerging technologies to investigate the global transcript profile of C. albicans cells infecting mucosal tissue in vivo and identify genes associated with host-induced morphogenesis. We propose to: 1) identify C. albicans genes expressed during the in vivo host-pathogen interaction; 2) identify a subset of C. albicans genes expressed specifically during mucosal-induced morphogenesis; 3) validate global expression datasets, and 4) assess the ability of knockout strains to undergo morphogenesis in vitro and in vivo. To our knowledge, this proposal will be the first to: 1) identify the transcriptional signature of C. albicans cells at the in vivo mucosal surface, and 2) elucidate new molecular targets and pathways that are independent of the major in vitro morphological regulators. These studies will generate significant insight into understanding the host-fungal pathogen interaction and allow the development of new antifungal strategies targeting the morphogenetic- and invasive-processes. PUBLIC HEALTH RELEVANCE Our findings will impact current treatment strategies by identifying virulence factors that may be targeted for prophylactic and therapeutic intervention. Such knowledge should accelerate our ability to diagnose, treat, and control the number one fungal pathogen of humans.