Mechanisms and consequences of cytoskeletal control of Helicobacter pylori cell shape

细胞骨架控制幽门螺杆菌细胞形状的机制和后果

基本信息

批准号：
10593366
负责人：
Sophie R. Sichel
金额：
$ 0.65万
依托单位：
FRED HUTCHINSON CANCER CENTER
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-08-01 至 2022-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10593366
关键词：
Mechanisms consequences cytoskeletal control Helicobacter

项目摘要

PROJECT SUMMARY/ABSTRACT Helicobacter pylori is a helical-shaped Gram-negative pathogen for which the only known niche is the human stomach. H. pylori infects 50% of the world’s population and causes chronic gastritis, which can progress to gastric cancers, or ulcers in a subset of patients [1]. How exactly H. pylori causes severe disease is not fully understood, but in general it occurs through eliciting inflammation. The bacterium’s helical cell shape is essential for multiple facets of early infection; helical strains of H. pylori more robustly colonize mice during acute (one week) infections than non-helical mutants that lack cell shape genes (curved or rod cells) [2-5]. Helical cell shape may promote colonization of the viscous mucous layer of the stomach through a corkscrewing mechanism [6] which allows H. pylori to reach the epithelium and colonize the epithelial surface [7]. Furthermore, additional evidence from mouse models suggests that in chronic infections (one or three months), helical H. pylori elicit higher levels of inflammation and hyperplasia than non-helical mutant strains [5]. How helical cell shape is determined and how it promotes colonization and inflammation of the stomach are two questions essential to our understanding of how H. pylori causes disease. Multiple proteins that are required for helical cell shape in H. pylori have been identified and proposed to form a “shapesome” complex that determines helical cell shape [2- 4, 8]. The hypothesis of this project is that the helical shape of H. pylori contributes to H. pylori’s ability to traverse the mucous layer and interact with the gastric mucosa to induce inflammation and is controlled by the “shapesome” which the cytoskeletal protein CcmA stabilizes and localizes to the inner membrane of H. pylori. The following aims will test this hypothesis: Aim 1 will characterize how each domain of CcmA contributes to polymerization and proper localization of CcmA, Aim 2 will determine whether proper intracellular localization of CcmA is modulated by its interaction partners and whether these interactions are impacted by cell shape-altering point mutations in CcmA, and Aim 3 will investigate whether localization to the epithelium through the mucous layer is impacted by alterations of helical parameters of H. pylori cells. This project will leverage advanced microscopy and organoid culture techniques to inform our understanding of how helical cell shape in H. pylori is determined and how helical cell shape impacts interactions with the gastric epithelium. The research fits the mission of the NIAID by providing knowledge that could advance the development of anti-virulence therapies for H. pylori infection considering clinical isolates of H. pylori increasingly show antibiotic resistance [13-15]. Additionally, this work will enhance understanding of how perturbation of helical cell shape impacts pathogenicity of H. pylori and could be applied to other helical rod-shaped gastrointestinal pathogens.

项目摘要/摘要幽门螺杆菌是一种螺旋形的革兰氏阴性病原体，唯一已知的生态位是人类胃。幽门螺杆菌感染50％的世界人口，并导致慢性胃炎，这可以发展为一部分患者的胃癌或溃疡[1]。幽门螺杆菌究竟如何导致严重疾病尚未完全理解，但总的来说，它是通过引起炎症而发生的。细菌的螺旋细胞形状必不可少对于早期感染的多个方面；幽门螺杆菌的螺旋菌株在急性期间更坚固地定居小鼠（一个周）感染比缺乏细胞形状基因（弯曲或杆细胞）的非螺旋突变体[2-5]。螺旋细胞形状可以通过开瓶器机制促进摊位粘性粘液层的定殖[6] 这使幽门螺杆菌可以到达上皮并定居上皮表面[7]。此外，附加小鼠模型的证据表明，在慢性感染（一三个月）中，幽门螺杆菌引起与非螺旋突变菌株相比，炎症和增生水平更高[5]。螺旋细胞形状的形状确定及其如何促进胃定植和炎症是两个问题我们对幽门螺杆菌如何引起疾病的理解。 H中螺旋细胞形状所需的多种蛋白质。幽门螺杆菌已被鉴定并提议形成一种“变形”复合物，该复合物决定螺旋细胞的形状[2- 4，8]。该项目的假设是幽门螺杆菌的螺旋形状有助于幽门螺杆菌的遍历能力粘液层并与胃粘膜相互作用以诱导注射，并由细胞骨架蛋白CCMA稳定并定位于幽门螺杆菌的内膜的“变形”。以下目的将检验以下假设：AIM 1将表征CCMA的每个领域如何贡献聚合和CCMA的适当定位，AIM 2将确定是否适当的细胞内定位 CCMA受其相互作用伙伴的调节，以及这些相互作用是否受细胞形状的影响 CCMA中的点突变和AIM 3将研究是否通过粘液定位到上皮层的影响受幽门螺杆菌细胞的螺旋参数的改变。该项目将利用高级显微镜和器官培养技术，以了解我们对幽门螺杆菌中螺旋细胞形状的理解确定以及螺旋细胞形状如何影响与胃上皮相互作用。这项研究适合通过提供可以推进反病毒疗法发展的知识来使NIAID的任务幽门螺杆菌感染考虑了幽门螺杆菌的临床分离株越来越多地表现出抗生素耐药性[13-15]。此外，这项工作将增强对螺旋细胞形状扰动如何影响致病性的理解幽门螺杆菌，可应用于其他螺旋形棒状胃肠道病原体。