An update on our understanding of Gram-positive bacterial membrane vesicles: discovery, functions, and applications

Abstract

Extracellular vesicles (EVs) are nano-sized particles released from cells into the extracellular environment, and are separated from eukaryotic cells, bacteria, and other organisms with cellular structures. EVs alter cell communication by delivering their contents and performing various functions depending on their cargo and release into certain environments or other cells. The cell walls of Gram-positive bacteria have a thick peptidoglycan layer and were previously thought to be unable to produce EVs. However, recent studies have demonstrated that Gram-positive bacterial EVs are crucial for health and disease. In this review, we have summarized the formation, composition, and characteristics of the contents, resistance to external stress, participation in immune regulation, and other functions of Gram-positive bacterial EVs, as well as their application in clinical diagnosis and treatment, to provide a new perspective to further our understanding of Gram-positive bacterial EVs.

The Role of Bacterial Extracellular Vesicles in the Immune Response to Pathogens, and Therapeutic Opportunities

“…When analyzing PDG digestion derivatives, it has been observed that some PDG chains associated with teichoic and lipoteichoic acids initiate inflammatory responses [ 64 ], suggesting that components of the bacterial cytoplasm or molecules associated with PDG may be the main mediators of pathogenicity. This idea is supported by studies that have identified (in EVs) cytotoxic molecules from B. anthracis [ 13 ], the presence of α-hemolysin from S. aureus , hyaluronate lyase from Propionibacterium acnes , or listeriolysin O from L. monocytogenes [ 66 ].…”

“…Tuberculosis, a disease caused by Mycobacterium tuberculosis , is considered the most lethal disease associated with a single microorganism, making it one of the major health emergencies worldwide [ 134 , 135 ]. The growing evidence of vesiculation in Gram-negative bacteria facilitated interest in investigating vesiculation in Gram-positive bacteria [ 13 , 65 , 66 ]. It prompted the investigation of vesiculation mechanisms in M. tuberculosis , especially after Marsollier et al isolated EVs of Mycobacterium ulcerans from skin biopsies of infected mice [ 14 ].…”