title: A Bifidobacterium probiotic strain and its soluble factors alleviate chloride secretion by human intestinal epithelial cells.
abstract: Previous studies indicate that certain probiotic bacterial strains or their soluble products can alleviate proinflammatory cytokine secretion by intestinal epithelial cells (IEC), but their impact on epithelial chloride (Cl(-)) secretion remains elusive. To further decipher the mechanisms of the cross-talk between bacteria/soluble factors and epithelial cells, we analyzed the capacity of the probiotic strain Bifidobacterium breve C50 (Bb C50), its conditioned medium, and other commensal Gram (+) bacteria to modulate epithelial Cl(-) secretion. The effect of Bb C50 on carbachol- (CCh) or forskolin (Fsk)-induced Cl(-) secretion was measured in an IEC line in Ussing chambers. The mechanisms involved in the regulation of Cl(-) secretion were assessed by measuring intracellular Ca(2+) concentration, phosphatase activity, protein kinase (PK) C and PKA activation, and cystic fibrosis transmembrane conductance regulator (CFTR) expression. CCh- or Fsk-induced Cl(-) secretion [short-circuit current (Isc): 151 +/- 28 and 98 +/- 14 microA/cm(2), respectively] was inhibited dose-dependently by Bb C50 (Isc 33 +/- 12 and 49 +/- 7 microA/cm(2) at multiplicity of infection 100; P < 0.02). Fsk-induced Cl(-) secretion was also inhibited by Lactobacillus rhamnosus 10893. No other inhibitory effect was recorded with the other Gram (+) bacteria tested. The inhibitory effect of Bb C50 on CCh-induced Cl(-) secretion targeted a step downstream of epithelial Ca(2+) mobilization and was associated with decreased PKC activity. Thus, Bb C50 and secreted soluble factors, by inhibiting phosphorylation processes, may promote intestinal homeostasis by controlling Cl(-) secretion.
authors.affiliation: INSERM U793, 75730 Paris, France.
authors.forename: Elise
authors.initials: E
authors.lastname: Heuvelin
authors.forename: Corinne
authors.initials: C
authors.lastname: Lebreton
authors.forename: Maurice
authors.initials: M
authors.lastname: Bichara
authors.forename: Nadine
authors.initials: N
authors.lastname: Cerf-Bensussan
authors.forename: Martine
authors.initials: M
authors.lastname: Heyman
mesh_terms: D001644:Bifidobacterium / Q000145:classification / Q000502:physiology; D002217:Carbachol / Q000494:pharmacology; D002460:Cell Line; D002712:Chlorides / Q000378:metabolism*; D005576:Colforsin / Q000494:pharmacology; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000382:microbiology; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology; D019936:Probiotics / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D002712:Chlorides; D012333:RNA, Messenger; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D005576:Colforsin; D002217:Carbachol