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.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
1R01AI079068-01
Application #
7506528
Study Section
Cell Structure and Function (CSF)
Program Officer
Korpela, Jukka K
Project Start
2009-07-17
Project End
2011-06-30
Budget Start
2009-07-17
Budget End
2010-06-30
Support Year
1
Fiscal Year
2009
Total Cost
$375,243
Indirect Cost
Name
Duke University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
044387793
City
Durham
State
NC
Country
United States
Zip Code
27705
Bonnington, Katherine E; Kuehn, Meta J (2016) Outer Membrane Vesicle Production Facilitates LPS Remodeling and Outer Membrane Maintenance in Salmonella during Environmental Transitions. MBio 7:
Schwechheimer, Carmen; Kuehn, Meta J (2015) Outer-membrane vesicles from Gram-negative bacteria: biogenesis and functions. Nat Rev Microbiol 13:605-19
Kulp, Adam J; Sun, Bo; Ai, Teresa et al. (2015) Genome-Wide Assessment of Outer Membrane Vesicle Production in Escherichia coli. PLoS One 10:e0139200
Schwechheimer, Carmen; Kuehn, Meta J (2013) Synthetic effect between envelope stress and lack of outer membrane vesicle production in Escherichia coli. J Bacteriol 195:4161-73
Macdonald, Ian A; Kuehn, Meta J (2013) Stress-induced outer membrane vesicle production by Pseudomonas aeruginosa. J Bacteriol 195:2971-81
Schwechheimer, Carmen; Sullivan, Claretta J; Kuehn, Meta J (2013) Envelope control of outer membrane vesicle production in Gram-negative bacteria. Biochemistry 52:3031-40
Chutkan, Halima; Macdonald, Ian; Manning, Andrew et al. (2013) Quantitative and qualitative preparations of bacterial outer membrane vesicles. Methods Mol Biol 966:259-72
Muralinath, Maneesha; Kuehn, Meta J; Roland, Kenneth L et al. (2011) Immunization with Salmonella enterica serovar Typhimurium-derived outer membrane vesicles delivering the pneumococcal protein PspA confers protection against challenge with Streptococcus pneumoniae. Infect Immun 79:887-94
Manning, Andrew J; Kuehn, Meta J (2011) Contribution of bacterial outer membrane vesicles to innate bacterial defense. BMC Microbiol 11:258
Kulp, Adam; Kuehn, Meta J (2011) Recognition of ?-strand motifs by RseB is required for ?(E) activity in Escherichia coli. J Bacteriol 193:6179-86

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