Bacterial biofilm-host interaction during Vibrio cholerae infection

描述（由申请人提供）：霍乱弧菌是霍乱的病原体，霍乱是一种急性脱水腹泻，在许多发展中国家流行。在流行病期间，霍乱弧菌与各种浮游生物和浮游动物一起生活在自然水生栖息地，通常以生物膜的形式存在。霍乱弧菌在生物膜中的存在不仅有助于其在自然环境中的生存，而且由于生物膜相关细胞对人类宿主的酸性胃环境具有抗性，因此增强了其传染性。然而，在进入定植位点后，霍乱弧菌如何脱离生物膜结构在肠道表面定植，以及霍乱弧菌如何根据宿主环境的变化控制其基因表达，在很大程度上是未知的。我们的初步结果表明，宿主因子(s)参与了扩散过程。因此，我们假设霍乱弧菌生物膜相关细胞在进入上肠后，与宿主因子相互作用并改变其转录谱，促进生物膜结构的快速扩散，从而有效地定殖肠道表面并引起疾病。我们将使用生化和化学方法确定宿主生物膜分离因子（BDF）的化学性质。我们将研究霍乱弧菌生物膜相关细胞如何响应BDF来改变生物膜相关基因的表达，以及这如何导致它们加速脱离。我们将在小鼠模型中测试bdf反应调节因子在生物膜分离和定植中的作用。我们还将应用微阵列分析来研究霍乱弧菌生物膜相关细胞进入小鼠肠道时的转录变化。对宿主因子与霍乱弧菌生物膜相互作用的研究可能会导致直接操纵细菌生物膜在体内生长的可能性。因此，生物膜相关病原体的最终治疗方法可以通过破坏有益的生物膜扩散（如霍乱弧菌）或增强可能对细菌生存有害的生物膜扩散（如在导管或各种植入物上的生物膜相关生长）来开发。公共卫生相关性：霍乱弧菌作为周期性全球流行病的原因，在传染病史上占有突出地位。尽管在医疗方面取得了重大进展，并且对霍乱弧菌毒力的分子过程有了更好的了解，但霍乱仍然以流行病的形式广泛发生，特别是在南亚、非洲和拉丁美洲。提出的这项研究将阐明霍乱弧菌在宿主-病原体相互作用中的遗传控制的重要性，目的是更好地了解霍乱弧菌的发病机制，并可能发现霍乱疾病的新治疗方案。

DESCRIPTION (provided by applicant): Vibrio cholerae is the causative agent of cholera, an acute dehydrating diarrhea that is epidemic in many developing countries. Between epidemics, V. cholerae live in natural aquatic habitats in association with various plankton and zooplankton, often in the form of biofilms. Existence of V. cholerae in biofilms not only helps its survival in the natural environment, but enhances its infectivity as well since biofilm associated cells are resistant to the acidic stomach environment of the human host. However, upon entering the colonization sites, how V. cholerae detaches from the biofilm structure to colonize intestinal surface and how V. cholerae controls its gene expression in response to the changes in host environments is largely unknown. Our preliminary results suggest that host factor(s) are involved in the dispersal process. We thus hypothesize that upon entering upper intestines, V. cholerae biofilm-associated cells interact with host factors and change their transcriptional profiles to promote rapid dispersal from the biofilm structure, thus efficiently colonize intestinal surface and cause diseases. We will identify the chemical properties of the host biofilm detaching factors (BDF) using biochemical and chemical approaches. We will investigate how V. cholerae biofilm-associated cells respond to BDF to alter the expression of biofilm-related genes and how this leads them to accelerate their detachment. We will test the roles of BDF-response regulators played in biofilm detachments and colonization in the mouse model. We will also apply microarray analysis to investigate transcriptional changes during V. cholerae biofilm associated cells enter into mouse intestines. This research into the interaction of host factors and V. cholerae biofilms may lead to the possibility of direct manipulation of bacterial biofilm growth in vivo. Thus ultimately therapeutic treatments of biofilm associated pathogens can be developed by disrupting beneficial biofilm dispersal (as in the case of V. cholerae) or enhancing biofilm dispersal where it may be detrimental to bacterial survival (such as biofilm associated growth on catheters or various implants).PUBLIC HEALTH RELEVANCE: Vibrio cholerae has figured prominently in the history of infectious diseases as a cause of periodic global epidemics. Despite major improvements in medical treatment as well as a better understanding of the molecular processes involved in the virulence of V. cholerae, cholera still occurs widely in epidemic form particularly in South Asia, Africa, and Latin America. This study proposed will shed light on importance of V. cholerae's genetic controls in host-pathogen interactions, with the goal of better understanding V. cholerae pathogenesis and, potentially, discovering novel treatment options for the cholera disease.