Extracellular Vesicles with Possible Roles in Gut Intestinal Tract Homeostasis and IBD

Abstract

The intestinal tract consists of various types of cells, such as epithelial cells, Paneth cells, macrophages, and lymphocytes, which constitute the intestinal immune system and play a significant role in maintaining intestinal homeostasis by producing antimicrobial materials and controlling the host-commensal balance. Various studies have found that the dysfunction of intestinal homeostasis contributes to the pathogenesis of inflammatory bowel disease (IBD). As a novel mediator, extracellular vesicles (EVs) have been recognized as effective communicators, not only between cells but also between cells and the organism. In recent years, EVs have been regarded as vital characters for dysregulated homeostasis and IBD in either the etiology or the pathology of intestinal inflammation. Here, we review recent studies on EVs associated with intestinal homeostasis and IBD and discuss their source, cargo, and origin, as well as their therapeutic effects on IBD, which mainly include artificial nanoparticles and EVs derived from microorganisms.

Mycobacterial Hsp65 antigen delivered by invasive Lactococcus lactis reduces intestinal inflammation and fibrosis in TNBS-induced chronic colitis model

“…We measured MPO as an inflammatory biomarker of colitis because an increased concentration of MPO indicates the infiltration of activated neutrophils into inflamed tissue and suggests an exacerbation of inflammation in the colon 27 . In the present study, significant differences could not be detected among the groups, even though the release of MPO is common in both acute and chronic inflammation 28 .…”

Microbiota‐derived extracellular vesicles and metabolic syndrome

“…Microbiota-derived EVs can be notably detected in all body fluids, such as urine, serum and cerebrospinal fluid, but also faeces samples and intestinal aspirate. 34,[50][51][52][53][54][55] Detailed techniques for EV purification and characterization have been developed in a position paper from the International Society of Extracellular Vesicles. 13 These guidelines are summarized under the term "minimal experimental requirements for definition of extracellular vesicles" to ensure the presence and purity of EV preparations.…”

“…Microbiota‐derived EVs can be notably detected in all body fluids, such as urine, serum and cerebrospinal fluid, but also faeces samples and intestinal aspirate 34,50–55 . Detailed techniques for EV purification and characterization have been developed in a position paper from the International Society of Extracellular Vesicles 13 .…”

Extracellular vesicles produced by the human commensal gut bacteriumBacteroides thetaiotaomicronaffect host immune pathways in a cell-type specific manner that are altered in inflammatory bowel disease

“…Bacteroides thetaiotaomicron (Bt) is a Gram-negative anaerobe that is a major constituent of the human caecal and colonic microbiota [3]. The administration of Bt in murine models of IBD ameliorates inflammation [4, 5] with the anti-inflammatory effects being at least in part mediated by its production of bacterial extracellular vesicles (BEVs). BEVs are released by both commensal Gram-negative and Gram-positive bacteria and have the potential to mediate cross-kingdom interactions with host cells via the delivery of their contents and cargo to affect host cell physiology and function [4].…”

“…The administration of Bt in murine models of IBD ameliorates inflammation [4, 5] with the anti-inflammatory effects being at least in part mediated by its production of bacterial extracellular vesicles (BEVs). BEVs are released by both commensal Gram-negative and Gram-positive bacteria and have the potential to mediate cross-kingdom interactions with host cells via the delivery of their contents and cargo to affect host cell physiology and function [4]. BEVs produced by Gram-negative bacteria such as Bt (outer membrane vesicles; OMVs) are small, spherical bilayered structures (20-400 nm) composed of phospholipids, lipopolysaccharides, peptidoglycan, outer membrane proteins, periplasmic contents including proteins, and some inner membrane and cytoplasmic fractions [6].…”