title: Probiotic bacteria Bifidobacterium animalis MB5 and Lactobacillus rhamnosus GG protect intestinal Caco-2 cells from the inflammation-associated response induced by enterotoxigenic Escherichia coli K88.
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.
authors.affiliation: Istituto Nazionale di Ricerca per gli Alimenti e la Nutrizione, Via Ardeatina 546, 00178 Rome, Italy.
authors.forename: Marianna
authors.initials: M
authors.lastname: Roselli
authors.forename: Alberto
authors.initials: A
authors.lastname: Finamore
authors.forename: Maria Serena
authors.initials: MS
authors.lastname: Britti
authors.forename: Elena
authors.initials: E
authors.lastname: Mengheri
mesh_terms: D001422:Bacterial Adhesion; D001644:Bifidobacterium / Q000502:physiology*; D018938:Caco-2 Cells; D002478:Cells, Cultured; D054360:Chemokine CXCL1; D019743:Chemokines, CXC / Q000235:genetics; D004926:Escherichia coli / Q000472:pathogenicity* / Q000502:physiology; D004927:Escherichia coli Infections / Q000276:immunology*; D005786:Gene Expression Regulation; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics; D007375:Interleukin-1 / Q000235:genetics; D016209:Interleukin-8 / Q000235:genetics; D007422:Intestines / Q000276:immunology / Q000382:microbiology; D052201:Lacticaseibacillus rhamnosus / Q000502:physiology*; D020556:Neutrophil Infiltration; D009504:Neutrophils / Q000378:metabolism; D019936:Probiotics; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016211:Transforming Growth Factor alpha / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
chemical_list: C475829:CXCL1 protein, human; D054360:Chemokine CXCL1; D019743:Chemokines, CXC; D036341:Intercellular Signaling Peptides and Proteins; D007375:Interleukin-1; D016209:Interleukin-8; D012333:RNA, Messenger; D016211:Transforming Growth Factor alpha; D014409:Tumor Necrosis Factor-alpha