Regulation of Clostridium difficile Colonization Factors

描述（由申请方提供）：艰难梭菌是一种革兰氏阳性专性厌氧菌，可引起抗生素相关性腹泻至伪膜性结肠炎等疾病。近年来，C.艰难梭菌感染增加。然而，对发病机制的基本方面只有有限的了解，例如细菌附着在肠上皮上的机制。由于宿主的定殖是建立感染的先决条件，因此必须确保宿主的定殖。 因此，必须确定细菌附着于宿主组织的潜在机制，因为这将推动急需的其他治疗和预防方案的开发。这个项目的长期目标是了解C。艰难梭菌附着并维持肠上皮的定殖。本提案的目的是确定鞭毛和IV型皮利以及控制其产生的机制如何影响C.难以在宿主组织中定植。本研究的中心假设是细菌信号分子c-di-GMP反向调节鞭毛和IV型皮利的生物合成，使其在适当的定殖阶段产生。这一假设将通过以下三个具体目标进行检验。具体目标1是确定IV型菌毛的作用，以及c-di-GMP对肠道定植和毒力的调节。具体目标2是确定鞭毛基因是如何被c-di-GMP调控的，以及调控如何影响毒力。具体目标3是确定感染过程中IV型菌毛和鞭毛产生的时空模式以及这些表面细胞器协调产生对C.很难在宿主体内定植并引起疾病。这一建议代表了一个全新的研究领域，以了解C。艰难梭菌病：控制梭菌定植因子的细胞内信号通路。很难通过定义法规和 鞭毛和IV型皮利的功能，这些研究将显着扩大我们的知识，如何 C.艰难梭菌控制宿主的定殖，并可揭示抑制肠定殖的靶点，从而预防疾病。

DESCRIPTION (provided by applicant): Clostridium difficile is a Gram-positive, obligate anaerobe that causes diseases ranging from antibiotic- associated diarrhea to pseudomembranous colitis. In recent years, the incidence and severity of C. difficile infections has increased. Yet there is only limited knowledge of fundamental aspects of pathogenesis, such as the mechanisms used by the bacterium to attach to the intestinal epithelium. Because colonization of the host is a prerequisite for establishing an infection, it is imperative that the mechanisms underlying bacterial attachment to host tissues be defined, as this will drive the much-needed development of additional treatment and prevention options. The long-term goal of this project is to understand how C. difficile attaches to and maintains colonization of the intestinal epithelium. The objective of this proposal is to determine how flagella and Type IV pili as well as the mechanisms controlling their production, impact the ability of C. difficile to colonize host tissues. The central hypothesis of this study is that the bacterial signaling molecule c-di-GMP oppositely regulates the biosynthesis of flagella and Type IV pili, allowing their production at appropriate stages of colonization. This hypothesis will be tested with the following three specific aims. Specific aim 1 is to determine the effect of the Type IV pilus and is regulation by c-di-GMP on intestinal colonization and virulence. Specific aim 2 is to determine how flagellar genes are regulated by c-di-GMP and how regulation affects virulence. Specific aim 3 is to determine the spatial and temporal patterns of Type IV pilus and flagellum production during infection and the importance of coordinating production of these surface organelles on the ability of C. difficile to colonize the host and cause disease. This proposal represents an entirely new area of investigation toward understanding C. difficile disease: the intracellular signaling pathways controlling colonization factors of C. difficile. By defining the regulation and function of flagella and Type IV pili, these studies will significantly expand our knowledge of how C. difficile controls colonization of the host and may reveal targets for inhibition of intestinal colonization to thereby prevent disease.