Table 2.

The roles of GBEVs in communication cross-talk between gut bacteria and host cells.

GBEVs source	Cargos	Function	Mechanism	Refs
Akkermansia muciniphila	Unknown	1. Protect the progression of dextran sulfate sodium-induced colitis; 2. Increase 5-HT levels in the host intestine.	Unknown	95–97
Bacteroides fragilis	PSA	Induction of immunomodulation and prevention of experimental colitis.	TLR2	91
Bacteroides thetaiotaomicron	Unknown	Promote the regulatory DC responses of healthy individuals.	Unknown	92
	Sulfatase enzymes	Promote inflammatory immune stimulation in genetically susceptible hosts.	Sulfatase-dependent manner	98
	MINPP	Promote intracellular Ca2+ signaling.	Unknown	99
Bacteroides vulgatus mpk	MAMPs	Induce semi-maturation of DCs cells and enhance that immune system silence caused by the strain	TLRs	90
Campylobacter jejuni	Proteases	Triggering the IL-8, IL-6, hBD-3 and TNF-α responses of T84 intestinal epithelial cells and are cytotoxic to Caco-2 IECs and Galleria mellonella larvae.	Unknown	100
Clostridium difficile	Translation-associated proteins	Inducing a pro-inflammatory response and inducing cytotoxicity of colonic epithelial cells.	Unknown	101
Escherichia coli BL21	LPS	Activate caspase-11.	TLR4-TRIF-GBPs	102
Escherichia coli C25	Unknown	It causes mild pro-inflammatory response in intestinal epithelial cells.	TLRs	93
Escherichia coli Nissle 1917	Unknown	1. Regulation of innate immunity of intestinal epithelial cells; 2. Up-regulation of tight junction protein expression in intestinal epithelial cells.	1. NOD1 2. Unknown	88,103
Escherichia coli W3110 msbB-mutant strain	Unknown	Induces massive production of IFN-γ and promotes T cell-mediated immune responses.	Unknown	104
Faecalibacterium prausnitzii	Unknown	Increase 5-HT levels in the host intestine.	Unknown	96
Fusobacterium nucleatum	1. Autotransporter proteins and other virulence factor (FadA, MORN2 and YadA); 2. Unknown; 3. Unknown	1. Destroy intestinal epithelial barrier; 2. Promote colon cancer development; 3. Regulation of innate immunity of intestinal epithelial cells.	1. FADD-RIPK1-caspase 3; 2. Unknown; 3. TLR2	25,105–107
Lacticaseibacillus paracasei	Unknown	Inhibit colon cancer development.	PDK1/AKT/Bcl-2	108
Lactobacillus plantarum	Unknown	Up-regulate the expression of host defense genes to provide protection for the host	Unknown	89
Lactobacillus reuteri	Glucosyltransferase, serine protease and elongation factor Tu	Enhancing immunomodulatory cell-mediated immunosuppression by activating macrophages to inhibit Th1 and Th17-mediated inflammatory responses	Unknown	109
Pediococcus pentosaceus	Unknown	Promote that M2-type polarization of macrophages	TLR2	110
Propionibacterium freudenreichii CIRM-BIA 129	SlpB	Modulate inflammatory responses	NF-κB	87
Pseudomonas aeruginosa	Unknown	Induces mitochondrial dysfunction in macrophages and inhibits host protein synthesis, ultimately inducing an inflammatory response	Unknown	111
Salmonella Typhimurium ATCC 14028	Unknown	Inhibit colon cancer development	Unknown	112
Vibrio cholerae O395	Unknown	Activate innate immune response of host	NOD1	113

Notes: DCs, dendritic cells; HFD, high-fat diet; GBPs, guanylate-binding proteins; MAMPs, microbe-associated molecular patterns; MINPP, mammalian InsP6 phosphatase; OMV, outer membrane vesicles; PSA, polysaccharide; SlpB, surface-layer protein B; TLRs, Toll-like receptors; TRIF, TIR domain-containing adaptor-inducing interferon-β; GBEVs: gut bacteria-derived extracellular vesicles; Refs: references.