Versatile effects of bacterium-released membrane vesicles on mammalian cells and infectious/inflammatory diseases

Abstract

Gram-negative bacterium-released outer-membrane vesicles (OMVs) and Gram-positive bacterium-released membrane vesicles (MVs) share significant similarities with mammalian cell-derived MVs (eg, microvesicles and exosomes) in terms of structure and their biological activities. Recent studies have revealed that bacterial OMVs/MVs could (1) interact with immune cells to regulate inflammatory responses, (2) transport virulence factors (eg, enzymes, DNA and small RNAs) to host cells and result in cell injury, (3) enhance barrier function by stimulating the expression of tight junction proteins in intestinal epithelial cells, (4) upregulate the expression of endothelial cell adhesion molecules, and (5) serve as natural nanocarriers for immunogenic antigens, enzyme support and drug delivery. In addition, OMVs/MVs can enter the systemic circulation and induce a variety of immunological and metabolic responses. This review highlights the recent advances in the understanding of OMV/MV biogenesis and their compositional remodeling. In addition, interactions between OMVs/MVs and various types of mammalian cells (ie, immune cells, epithelial cells, and endothelial cells) and their pathological/preventive effects on infectious/inflammatory diseases are summarized. Finally, methods for engineering OMVs/MVs and their therapeutic potential are discussed.

Interplay between Peptidoglycan Biology and Virulence in Gram-Negative Pathogens

“…Therefore, this classic concept In this sense, it has to be noted that some works have recently shown in E. coli but also in other more niche-specific species, such as some periodontal pathogens (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia), the association between their released OMVs and the activation of NOD1 and/or NOD2 in the host, which strongly suggests that the presence of PGN fragments within the cited vesicles potentially contributes to the inflammatory response in the infected tissues (152)(153)(154). In fact, in recent years OMVs have been recognized to be effective virulence factor delivery systems, and hence, the presence of certain PGN fragments within OMVs could contribute to this role (155)(156)(157). Moreover, to conclude and as additional evidence that Gram-negative PGN biology interacts with pathogenesis (in this case, with a close relation to OMVs), some studies have directly related PGN dynamics to the modulation of OMV production levels, which would have obvious consequences for virulence (158,159).…”

Gut microbiota: a new player in regulating immune- and chemo-therapy efficacy

“…OMVs are generated by blebbing outwards from the OM, during which process they include soluble components inside and adherent material, on the external surface [109] . EVs produced by gram-positive bacteria are structurally similar to OMVs, with sizes ranging from 10 to 400 nm [107] . They carry bacterial components including nucleic acid, proteins, lipids, enzymes and toxins.…”

Therapeutic potential role of exosomes for ischemic stroke

“…These specific proteins contained in exosomes can reveal which mother cells they are from. For example, exosomes derived from intestinal epithelial cells contain various metabolic enzymes [16]; exosomes derived from T cells have T cell surface receptor proteins; and the ones from dendritic cells contain a large number of proteins associated with antigen-presenting cells, such as MHC class I molecules, MHC class II molecules, and costimulatory molecules CD80 and CD86 [17]. These proteins can be used as markers to provide a basis for early diagnosis of disease, such as tumors.…”