Biophysical determinants of chemotaxis in Helicobacter pylori

幽门螺杆菌趋化性的生物物理决定因素

• 批准号: 10367389
• 负责人: Pushkar Prakash Lele
• 金额: $ 38.09万
• 依托单位: TEXAS ENGINEERING EXPERIMENT STATION
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-02-01 至 2026-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10367389
• 关键词: Adaptor Signaling Protein; Address; Anti-Bacterial Agents; Bacteria; Biological Assay; Biophysical Process; Biophysics; Cells; Chemicals; Chemoreceptors; Chemotaxis; Chimeric Proteins; Coupling; Data; Detection; Development; Dose; Environment; Enzymes; Escherichia coli; Flagella; Fluorescence Resonance Energy Transfer; Goals; Habitats; Helicobacter Infections; Helicobacter pylori; Homologous Gene; Imaging Techniques; Individual; Infection; Inflammation; Knowledge; Ligands; Literature; Location; Mastigophora; Measures; Mediating; Methods; Microscopy; Modeling; Molecular; Motor; Outcome; Output; Pattern; Peptic Ulcer; Phase; Phosphotransferases; Play; Population; Prognosis; Proteins; Research; Role; Rotation; Running; Signal Transduction; Source; Standard Model; Stomach; Swimming; Techniques; Testing; Time; Work; antibiotic resistant infections; base; biophysical techniques; cell motility; desensitization; experimental study; extracellular; innovation; insight; laser tweezer; malignant stomach neoplasm; migration; novel; novel strategies; prevent; protein-histidine kinase; receptor; response; simulation

Project Abstract Infections by the motile bacterial species, Helicobacter pylori, are promoted by chemotaxis, which refers to the ability to migrate towards favorable chemical environments. H. pylori infections are a major cause of peptic ulcers and gastric cancers. Yet, the biophysical mechanisms of chemotaxis in H. pylori are not understood. In the canonical chemotaxis network, chemoreceptors sense extracellular ligands and regulate the activity of a chemotaxis kinase. The kinase in turn modulates flagellar functions to bias bacterial migration. To prevent the network from desensitizing upon ligand-detection, two enzymes, CheR and CheB, continuously reset the kinase activity. Such resetting (adaptation) increases the dynamic range of ligand sensing in the network, without which the cell cannot continue migrating up or down chemical gradients. However, H. pylori lack CheR and CheB homologues. Also, the pattern of motility in H. pylori is different from the standard model, Escherichia coli, since H. pylori localize all their flagella at a single pole – individual cells swim forward (run) and backward (reverse), rather than running and tumbling as E. coli do. This subtle difference in motility is predicted to give rise to multiple chemotaxis errors in the canonical framework. Hence, current mechanistic models of chemotaxis are unable to explain biased and error-free migration in H. pylori. Without a fundamental understanding of chemotaxis in H. pylori, the development of antibacterials that target chemotaxis will likely remain limited. In the proposed work, the PI’s primary goal is to explain how the chemotaxis network modulates flagellar functions to promote chemotaxis in H. pylori. The PI’s long term goal is to use the insights from the proposed work to develop innovative methods to prevent H. pylori infections by inhibiting chemotaxis. The PI will make use of a novel technique that overcomes the status quo by allowing quantification of flagellar functions without probing individual flagellar motors. Through a combination of optical tweezers, phase microscopy, and stochastic modeling, the PI will determine how chemotaxis errors are prevented at a single cell and population level in H. pylori. The team will pioneer the development of novel assays, including a FRET assay, to experimentally measure chemotaxis signaling in H. pylori. The PI will also determine the role of key coupling proteins that have been hypothesized to play a major role in chemotaxis adaptation. In addition to establishing the biophysical principles of chemotaxis in H. pylori, the following payoffs are anticipated: 1) a paradigm will be established for understanding chemotaxis migration in other run-reversing species, 2) novel mechanisms of chemotaxis adaptation are likely to be elucidated, 3. a FRET-based assay will be developed, which will significantly boost current efforts in the field to understand chemoreceptor functions and chemotaxis signaling mechanisms in H. pylori. Successful execution of the projects will enable a major advance since chemotaxis strategies remain poorly understood in a large majority of bacterial species.

项目摘要 运动性细菌幽门螺杆菌的感染是由趋化性促进的，趋化性 是指向有利的化学环境迁移的能力。幽门螺杆菌感染是主要原因 消化性溃疡和胃癌。然而，幽门螺杆菌趋化性的生物物理机制尚不明确。 明白了。在典型的趋化网络中，化学感受器感知细胞外配体并调节 趋化激酶的活性。该激酶反过来调节鞭毛功能以偏向细菌迁移。到 连续防止配体检测时网络脱敏，两种酶 CheR 和 CheB 重置激酶活性。这种重置（适应）增加了配体传感的动态范围 网络，没有这个网络，细胞就无法继续向上或向下化学梯度迁移。然而，幽门螺杆菌 缺乏 CheR 和 CheB 同源物。此外，幽门螺杆菌的运动模式与标准模型不同， 大肠杆菌，因为幽门螺杆菌将其所有鞭毛定位在一个极点 - 单个细胞向前游动（奔跑） 和向后（反向），而不是像大肠杆菌那样奔跑和翻滚。这种运动性的细微差别是 预计会在规范框架中引起多种趋化性错误。因此，目前的机械 趋化性模型无法解释幽门螺杆菌中的有偏且无差错的迁移。没有基础的 了解幽门螺杆菌的趋化性后，针对趋化性的抗菌药物的开发可能会 仍然有限。在拟议的工作中，PI 的主要目标是解释趋化网络如何 调节鞭毛功能以促进幽门螺杆菌的趋化性。 PI 的长期目标是利用这些见解 来自拟议的工作，开发通过抑制趋化性来预防幽门螺杆菌感染的创新方法。 PI 将利用一种新技术，通过对鞭毛进行量化来克服现状。 功能无需探测单个鞭毛电机。通过光镊的组合，相位 显微镜和随机建模，PI 将确定如何在单个 幽门螺杆菌的细胞和群体水平。该团队将率先开发新型检测方法，包括 FRET 测定，通过实验测量幽门螺杆菌中的趋化信号传导。 PI 还将确定关键人员的角色 耦合蛋白被假设在趋化适应中发挥重要作用。此外 建立幽门螺杆菌趋化性的生物物理原理，预计将获得以下回报：1）a 将建立范式来理解其他逆转物种的趋化性迁移，2）新颖 趋化适应机制可能会得到阐明， 3. 将开发基于 FRET 的检测方法， 这将极大地促进当前该领域了解化学感受器功能和趋化性的努力 幽门螺杆菌中的信号传导机制。这些项目的成功执行将取得重大进展 大多数细菌物种的趋化策略仍然知之甚少。