Gram-negative bacterial membrane vesicle release in response to the host-environment: different threats, same trick?

Abstract

Bacteria are confronted with a multitude of stressors when occupying niches within the host. These stressors originate from host defense mechanisms, other bacteria during niche competition or result from physiological challenges such as nutrient limitation. To counteract these stressors, bacteria have developed a stress-induced network to mount the adaptations required for survival. These stress-induced adaptations include the release of membrane vesicles from the bacterial envelope. Membrane vesicles can provide bacteria with a plethora of immediate and ultimate benefits for coping with environmental stressors. This review addresses how membrane vesicles aid Gram-negative bacteria to cope with host-associated stress factors, focusing on vesicle biogenesis and the physiological functions. As many of the pathways, that drive vesicle biogenesis, confer we propose that shedding of membrane vesicles by Gram-negative bacteria entails an integrated part of general stress responses.

Host- and Microbiota-Derived Extracellular Vesicles, Immune Function, and Disease Development

“…Whether the outer inner membrane vesicles are produced by commensal G− bacteria has not been reported. There are three models attempting to explain OMV production, as described in detail elsewhere [97], which all suggest that OMV production is a strategy to maintain outer membrane homeostasis. According to these three models, OMVs are produced when the outer membrane lipid asymmetry is compromised (model A), misfolded proteins accumulate in the outer membrane (model B) or when lipopolysaccharide (LPS) is modified (model C) [97].…”

“…There are three models attempting to explain OMV production, as described in detail elsewhere [97], which all suggest that OMV production is a strategy to maintain outer membrane homeostasis. According to these three models, OMVs are produced when the outer membrane lipid asymmetry is compromised (model A), misfolded proteins accumulate in the outer membrane (model B) or when lipopolysaccharide (LPS) is modified (model C) [97]. Recently, explosive cell lysis conditions have been shown to increase the production of OMVs by P. aeruginosa [98].…”

“…Recently, explosive cell lysis conditions have been shown to increase the production of OMVs by P. aeruginosa [98]. Most studies looking at the impacts of environmental factors on OMV release focused on pathogenic bacteria have identified that elements that would affect the outer membrane integrity such as the nutritional environment, the presence of antimicrobial peptides either host-derived, or antibiotics as well as stressors such as temperature and oxygen availability can promote OMV release [97]. Proteomic analysis of OMV membrane components has shown that membrane proteins can be sub-classified into six categories based on their function: (1) bacteria survival; (2) nutrient sensing; (3) ABC transporters; (4) killing competing bacteria; (5) virulence towards host cells; and (6) modulation of host immune function [99].…”

Host-microbe cross-talk in the lung microenvironment: implications for understanding and treating chronic lung disease

“…OMVs are spherical bilayered membrane vesicles released from the surface of both Gram-negative and Gram-positive bacteria, and contain much of the biological material from the parent bacterium, but in a nonreplicative form [ 140 , 141 ]. Evidence suggests that the release of OMVs provides bacteria with competitive advantages when exposed to acute and chronic host-associated stressors [ 142 ]. They may protect bacteria against innate and adaptive immune responses [ 143 – 145 ], antimicrobial peptides and antibiotics [ 146 , 147 ].…”

In vitro Analysis of O-Antigen-Specific Bacteriophage P22 Inactivation by Salmonella Outer Membrane Vesicles

“…Moreover, EM images of our samples revealed flagella-like structures that apparently had co-purified with the OMVs. In principle, it would be also possible that additional periplasmic proteins are present in the lumen of these naturally budded vesicles or that they display increased amounts of OM proteins (Volgers et al, 2018). However, the small yield of these OMVs isolated from culture supernatants impeded a further detailed proteomic analysis.…”