The VSL#3 probiotic formula induces mucin gene expression and secretion in colonic epithelial cells

Abstract

Several studies have stressed the importance of the microbiota in the maintenance of the gastrointestinal epithelium. Administration of probiotic bacteria, supplements composed of microbiota constituents, was previously shown to diminish symptoms in patients suffering from inflammatory bowel diseases. This raises the possibility that probiotics may play an active role in enhancing the intestinal barrier at the mucosal surface. In this study, we investigated whether the clinically tested VSL#3 probiotic formula and/or its secreted components can augment the protective mucus layer in vivo and in vitro. For in vivo studies, Wistar rats were orally administered the probiotic mixture VSL#3 on a daily basis for seven days. After treatment, basal luminal mucin content increased by 60%. In addition, we exposed isolated rat colonic loops to the VSL#3 probiotic formula, which significantly stimulated colonic mucin (MUC) secretion and MUC2 gene expression; however, MUC1 and MUC3 gene expression were only slightly elevated. The effect of the VSL#3 mucin secretagogue was also tested in vitro by use of LS 174T colonic epithelial cells. In contrast to the animal studies, cultured cells incubated with VSL#3 bacteria did not exhibit increased mucin secretion. However, the bacterial secreted products contained in the conditioned media stimulated a remarkable mucin secretion effect. Among the three bacterial groups (Lactobacilli, Bifidobacteria, and Streptococci) contained in VSL#3, the Lactobacillus species were the strongest potentiator of mucin secretion in vitro. A preliminary characterization of the putative mucin secretagogue suggested that it was a heat-resistant soluble compound, which is not sensitive to protease and DNase treatment. These findings contribute to a better understanding of the complex and beneficial interaction between colonic epithelial cells and intestinal bacteria.

Muc-2–Deficient Mice Display a Sex-Specific, COX-2–Related Impairment of Gastric Mucosal Repair

“…7 MUC-5AC, a secretory mucin, is the major mucin in the normal stomach, whereas MUC-2, another secretory mucin, predominates in the small and large intestine. 8 Altered mucin expression patterns have been observed in different digestive disorders. For example, reduced expression of MUC-5AC and MUC-6 has been reported in gastric carcinomas.…”

Probiotics and health: An evidence-based review

“…The tolerance of the microbiota is mediated by some complementary mechanisms: (1) microbiota bacteria do not express virulence factors, e.g. secondary to chemical modifications of pathogenassociated molecular patterns, antigenic structures recognized by toll-like receptors (TLRs) on the surface of immune system cells or (2) some commensal bacteria are able to suppress inflammatory processes (for example by down-regulation of the activity of NF-B [22]). …”

“…In fact: (1) probiotics modulate and stabilize the composition of the microbiota and, therefore, may have immunomodulatory effects; (2) some probiotics are able to inhibit the inflammatory response of the intestinal immune system through inhibition of NF-B activation or in combination with an anti-apoptotic action on intestinal epithelial cells [31,32]; (3) some probiotics are able to increase the activity of Natural Killer (NK) cells [33,34], which are first line of defense as they can perform cytotoxic activities independent from prior sensitization to antigens; (4) some probiotics increase the secretion of mucus [22]; (5) some probiotics have a direct immunomodulatory action: after being captured in the Peyer's patches, they can induce the secretion of cytokines and the expression of co-stimulatory molecules by antigen presenting cells (APC) [35]; (6) some strains of lactobacilli induce dendritic cells (DC) maturation [36]. DC can, through their particular cytostructure, pass through the layer of epithelial cells and capture antigens directly from the lumen.…”

Probiotics – do they have a role in the pig industry?

“…This appears to be a multi-factorial process involving both induction of mucus secretion from goblet cells (Mack et al, 1999;Caballero-Franco et al, 2007) and maintenance of the tight cell junctions between cells (Madsen et al, 2001;Roselli et al, 2007;Putaala et al, 2008). This function may be most important in counteracting the effects of pathogens, which often exert gastrointestinal effects by weakening the junctions between cells allowing for translocation of the pathogens and activation of inflammatory signals or establishment of local inflammatory lesions.…”