Lactobacillus plantarum is a Gram-positive bacillus known for its effect as a probiotic agent. The goal of the study was to determine whether L. plantarum is capable of inhibiting the transepithelial neutrophil migration induced by enteropathogenic Escherichia coli (EPEC).
Cultured intestinal epithelial T-84 cell monolayers were rapidly infected with EPEC. L. plantarum or culture supernatants were added to the monolayers before and after the infection. Indium-labeled neutrophils were added to the basolateral side of inverted monolayers. After 150-minute incubation, radioactivity of the neutrophils that migrated in the physiologic direction was assayed, and the number of migrating neutrophils was calculated. L. plantarum was also added to the monolayers before and after EPEC infection, and the number of adherent EPEC was determined by plate counting.
EPEC-induced neutrophil migration and EPEC binding to monolayers were inhibited by viable L. plantarum but only when added to the monolayers before EPEC. Culture supernatants failed to inhibit the neutrophil migration.
These results suggest that L. plantarum is beneficial in inhibiting neutrophil migration induced by EPEC, but only when preincubated with host epithelia. Rather than an indirect effect through a secreted substance produced by the probiotic agent, its effect is direct and requires the presence of the bacterium.
"Thus, the prevention of excessive neutrophil recruitment may represent a tool to counteract the development of pathogen-induced inflammatory reactions. A reduction of inflammatory cell infiltration by certain lactobacilli and bifidobacteria in chemically or pathogen-induced intestinal inflammation has been reported (Hidemura et al. 2003; Michail & Abernathy, 2003; Peran et al. 2005). However, it is not clear whether the regulation of inflammatory cell migration is a common effect of probiotics . "
[Show abstract][Hide abstract] ABSTRACT: Probiotic bacteria may provide protection against intestinal damage induced by pathogens, but the underlying mechanisms are still largely unknown. We investigated whether Bifidobacterium animalis MB5 and Lactobacillus rhamnosus GG (LGG) protected intestinal Caco-2 cells from the inflammation-associated response induced by enterotoxigenic Escherichia coli (ETEC) K88, by inhibiting pathogen attachment to the cells, which is the first step of ETEC pathogenicity, and regulating neutrophil recruitment, a crucial component of inflammation. A partial reduction of ETEC adhesion was exerted by probiotics and their culture supernatant fractions either undigested or digested with proteases. ETEC viability was unaffected by the presence of B. animalis, LGG or their supernatant fractions in the culture medium, indicating an absence of probiotic bactericidal activity. Probiotics and their supernatant fractions, either undigested or digested with proteases, strongly inhibited the neutrophil transmigration caused by ETEC. Both B. animalis and LGG counteracted the pathogen-induced up regulation of IL-8, growth-related oncogene-alpha and epithelial neutrophil-activating peptide-78 gene expression, which are chemokines essential for neutrophil migration. Moreover, the probiotics prevented the ETEC-induced increased expression of IL-1beta and TNF-alpha and decrease of transforming growth factor-alpha, which are regulators of chemokine expression. These results indicate that B. animalis MB5 and LGG protect intestinal cells from the inflammation-associated response caused by ETEC K88 by partly reducing pathogen adhesion and by counteracting neutrophil migration, probably through the regulation of chemokine and cytokine expression.
British Journal Of Nutrition 07/2006; 95(6):1177-84. DOI:10.1079/BJN20051681 · 3.45 Impact Factor
"Furthermore, probiotic bacteria have been shown to enhance the adaptive immune response and antibody formation [7,8]. Inhibition of adherence of attaching and effacing organisms , modulation of the mucosal barrier function [10,11] as well as inhibition of neutrophil migration  may also be important mechanisms whereby probiotics can impact in intestinal diseases. "
[Show abstract][Hide abstract] ABSTRACT: The use of live microorganisms to influence positively the course of intestinal disorders such as infectious diarrhea or chronic inflammatory conditions has recently gained increasing interest as a therapeutic alternative. In vitro and in vivo investigations have demonstrated that probiotic-host eukaryotic cell interactions evoke a large number of responses potentially responsible for the effects of probiotics. The aim of this study was to improve our understanding of the E. coli Nissle 1917-host interaction by analyzing the gene expression pattern initiated by this probiotic in human intestinal epithelial cells.
Gene expression profiles of Caco-2 cells treated with E. coli Nissle 1917 were analyzed with microarrays. A second human intestinal cell line and also pieces of small intestine from BALB/c mice were used to confirm regulatory data of selected genes by real-time RT-PCR and cytometric bead array (CBA) to detect secretion of corresponding proteins.
Whole genome expression analysis revealed 126 genes specifically regulated after treatment of confluent Caco-2 cells with E. coli Nissle 1917. Among others, expression of genes encoding the proinflammatory molecules monocyte chemoattractant protein-1 ligand 2 (MCP-1), macrophage inflammatory protein-2 alpha (MIP-2alpha) and macrophage inflammatory protein-2 beta (MIP-2beta) was increased up to 10 fold. Caco-2 cells cocultured with E. coli Nissle 1917 also secreted high amounts of MCP-1 protein. Elevated levels of MCP-1 and MIP-2alpha mRNA could be confirmed with Lovo cells. MCP-1 gene expression was also up-regulated in mouse intestinal tissue.
Thus, probiotic E. coli Nissle 1917 specifically upregulates expression of proinflammatory genes and proteins in human and mouse intestinal epithelial cells.
BMC Medical Genetics 02/2005; 6(1):43. DOI:10.1186/1471-2350-6-43 · 2.08 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.