Probiotics and commensals reverse TNF-alpha- and IFN-gamma-induced dysfunction in human intestinal epithelial cells.
OBJECTIVE
Commensal bacteria are crucial for the development of the mucosal immune system. Probiotics are commensals with special characteristics and may protect mucosal surfaces against pathogens. Pathogens cause significant phenotypic alterations in infected epithelial cells, and probiotics reverse these deleterious responses. We hypothesized that probiotics and/or commensals may also reverse epithelial damage produced by cytokines.


METHODS
Human intestinal epithelial cells were exposed basolaterally to interferon (IFN)-gamma (10(3) U/mL) or tumor necrosis factor (TNF)-alpha (10 ng/mL) for up to 48 hours and assessed for ion transport, transepithelial resistance (TER), and epithelial permeability in the presence or absence of probiotics (Streptococcus thermophilus [ST] and Lactobacillus acidophilus [LA]), or the commensal, Bacteroides thetaiotaomicron (BT).


RESULTS
Agonist-stimulated chloride secretion was inhibited by IFN-gamma, an effect prevented by ST/LA or BT. The ability of ST/LA or BT to restore Cl(-) secretion was blocked by inhibitors of p38 MAPK, ERK1, 2, and PI3K. The cystic fibrosis transmembrane conductance regulator (CFTR) and the NKCC1 cotransporter were down-regulated by IFN-gamma, and ST/LA pretreatment reversed this effect. Both TNF-alpha and IFN-gamma significantly reduced TER and increased epithelial permeability, effects prevented by ST/LA or BT. A Janus kinase (JAK) inhibitor synergistically potentiated effects of ST/LA or BT on TER and permeability, but p38, ERK1, 2, or PI3K inhibition did not. Finally, only probiotic-treated epithelial cells exposed to cytokines showed reduced activation of SOCS3 and STAT1,3.


CONCLUSIONS
Deleterious effects of TNF-alpha and IFN-gamma on epithelial function are prevented by probiotic, and to a lesser extent, commensal pretreatment. These data extend the spectrum of effects of such bacteria on intestinal epithelial function and may justify their use in inflammatory disorders.
Resta-Lenert
Silvia
S
Department of Medicine, University of California, San Diego, School of Medicine, San Diego, California, USA.
Barrett
Kim E
KE
D001439:Bacteroides; D002460:Cell Line; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D007371:Interferon-gamma / Q000037:antagonists & inhibitors*; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000378:metabolism; D017136:Ion Transport / Q000187:drug effects; D007779:Lactobacillus acidophilus; D000072000:NF-KappaB Inhibitor alpha; D019936:Probiotics / Q000494:pharmacology*; D050796:STAT3 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D048249:Streptococcus thermophilus; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*
D020672:I-kappa B Proteins; C000606204:NFKBIA protein, human; C106644:SOCS3 protein, human; D050796:STAT3 Transcription Factor; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D014409:Tumor Necrosis Factor-alpha; D000072000:NF-KappaB Inhibitor alpha; D007371:Interferon-gamma