Biogenesis and Function of Bacterial Outer Membrane Vesicles

描述（由申请人提供）：该项目的长期目标是了解革兰氏阴性菌产生的外膜囊泡的基本方面：它们是如何以及为什么产生的？外膜囊泡占生长培养物中总外膜蛋白的0.1 - 1%，迄今为止研究的所有非致病性和致病性细菌都能产生外膜囊泡，毒性细菌通常比非致病性细菌产生更多的毒性囊泡。然而，关于它们如何以及为什么产生的基本过程是未知的。以前，我们已经发现外膜囊泡有助于革兰氏阴性菌的基本应激反应。我们认为外膜囊泡的产生是由特定的包膜成分控制的，并使质周和外膜内容物在响应环境变化和应力时发生重塑。快速替换细胞包膜蛋白和脂质以及囊泡介导的有毒成分释放可能是细菌在环境中生存的关键因素，特别是适应压力。利用新发现的囊泡突变体和本实验室开发的生物化学技术，本研究旨在阐明囊泡促进细菌适应的机制。本研究的研究目的如下：1)表征细菌囊泡包膜对应激的响应；2)鉴定和表征囊泡通路中的基因；3)表征囊泡在细胞包膜重塑中的作用。结果将产生期待已久的关于囊泡形成所需的细菌过程的见解，并将揭示有关这种新描述的应激反应的细节。通过比较我们在细菌和相关真核外泌体研究中的发现，将揭示应激产物管理的一般生物学原理。对人类健康的影响是一种常见细菌过程的特征，可以靶向治疗以增加细菌对抗生素治疗的敏感性。

DESCRIPTION (provided by applicant): The long-term goal of this project is to understand the fundamental aspects of outer membrane vesicles produced by Gram-negative bacteria: How and why are they made? Outer membrane vesicles represent 0.1 to 1% of total outer membrane protein in a growing culture and are produced by all non-pathogenic and pathogenic bacteria studied to date, with virulent bacteria typically producing toxic vesicles and more than non-pathogenic counterparts. Yet the basic processes regarding how and why they are made are unknown. Previously, we have found that outer membrane vesicles contribute a basic stress response of Gram-negative bacteria. We propose that outer membrane vesicle production is governed by specific envelope components and enables remodeling of the periplasmic and outer membrane content in response to environmental changes and stresses. Rapid replacement of cell envelope protein and lipid and vesicle-mediated release of toxic components could be key elements of bacterial survival in the environment, particularly to accommodate stress. Using newly identified vesiculation mutants and biochemistry techniques developed in this laboratory, this research aims to elucidate the mechanism by which vesicles contribute to bacterial adaptation. The research objectives of this study are the following: 1) Characterize the bacterial vesiculation envelope response to stress, 2) Identify and characterize genes in the vesiculation pathway, and 3) Characterize the role of vesicles in cell envelope remodeling. The results will yield long-awaited insight regarding the bacterial processes required for vesicle formation and will reveal details regarding this newly describe stress response. General biological principles of stress product management will be revealed by comparing our findings in the study of bacteria to the related eukaryotic exosomes. The impact on human health is the characterization of a common bacterial process that can be targeted therapeutically to increase bacterial sensitivity to antibiotic treatment. PUBLIC HEALTH RELEVANCE: This project benefits public health by detailing our understanding of bacterial vesiculation, a secretory process common too many pathogenic bacteria that enables bacteria to resist antibiotics and to disperse toxic factors into infected tissues. The proposed research focuses on exposing the molecular basis for vesiculation and aims to facilitate development of this potential therapeutic target.