Soluble factors from Lactobacillus GG activate MAPKs and induce cytoprotective heat shock proteins in intestinal epithelial cells

Abstract

Conditioned media from the probiotic Lactobacillus GG (LGG-CM) induce heat shock protein (Hsp) expression in intestinal epithelial cells. LGG-CM induces both Hsp25 and Hsp72 in a time- and concentration-dependent manner. These effects are mediated by a low-molecular-weight peptide that is acid and heat stable. DNA microarray experiments demonstrate that Hsp72 is one of the most highly upregulated genes in response to LGG-CM treatment. Real-time PCR and electrophoretic mobility shift assay confirm that regulation of Hsp induction is at least in part transcriptional in nature, involving heat shock factor-1. Although Hsps are not induced for hours after exposure, transient exposure to LGG-CM is sufficient to initiate the signal for Hsp induction, suggesting that signal transduction pathways may be involved. Experiments confirm that LGG-CM modulates the activity of certain signaling pathways in intestinal epithelial cells by activating MAP kinases. Inhibitors of p38 and JNK block the expression of Hsp72 normally induced by LGG-CM. Functional studies indicate that LGG-CM treatment of gut epithelial cells protects them from oxidant stress, perhaps by preserving cytoskeletal integrity. By inducing the expression of cytoprotective Hsps in gut epithelial cells, and by activating signal transduction pathways, the peptide product(s) secreted by LGG may contribute to the beneficial clinical effects attributed to this probiotic.

Lactobacillus supplementation for diarrhoea related to chemotherapy of colorectal cancer: a randomised study

“…Probiotics may also reduce radiation therapy-related diarrhoea (Salminen et al, 1988;Urbancsek et al, 2001;Delia et al, 2002). The mode of action is not fully understood, but probiotics are involved in some cytoprotective processes, such as induction of heat-shock protein expression in intestinal epithelial cells (Tao et al, 2006), and prevention of cytokine-induced epithelial cell damage (Yan et al, 2007).…”

Flagellin is required for salmonella-induced expression of heat shock protein Hsp25 in intestinal epithelium

“…Intestinal epithelial cells grown in culture were washed and then harvested by gentle scraping with a rubber policeman into ice-cold PBS, pelleted (14,000 g for 20 s), and then resuspended in lysis buffer [10 mM Tris, pH 7.4, 5 mM MgCl2, 50 U/ml DNAse and RNAse, plus complete protease inhibitor cocktail (Roche Molecular Biochemicals, Indianapolis, IN)] to disrupt the cells as previously described (25). Protein concentrations were determined from an aliquot by using the bicinchoninic acid procedure (23).…”

“…Cells were then harvested immediately after treatment with flagellin for Western blot analysis (MAPK phosphorylation). MAPK assays were performed as previously described elsewhere (25). Antibodies used were specific for p38 MAPK (no.…”

“…Flagellin has previously been shown to activate MAP kinases (28). In addition, MAP kinase activation by some nonflagellated bacteria results in induction of heat shock proteins in intestinal epithelial cells (25). Therefore, to further elucidate the mechanism behind Hsp25 induction by flagellin, the role of flagellin-mediated MAPK activation in the induction of Hsp25 expression was explored.…”

Probiotics and health: An evidence-based review

“…Heat shock proteins in the gut include hsp25 (that stabilizes actin) and hsp72 (that prevents cell denaturation). These mechanisms help maintaining efficient tight junctions between IEC, thus promoting the function of the mucosal barrier [119]. Probiotics in the gut induce the production of cytoprotective heat shock proteins [120].…”