Cytokine-induced epithelial permeability changes are regulated by the activation of the p38 mitogen-activated protein kinase pathway in cultured Caco-2 cells.
Increased intestinal/epithelial permeability in sepsis and endotoxemia has been noted to be induced by proinflammatory cytokines such as interferon-gamma, TNF-alpha, and IL-1beta. The p38 mitogen-activated protein kinase (MAPK) signaling pathway plays an important role in regulating the inflammatory response induced by these cytokines. We tested the hypothesis that epithelial permeability changes are regulated through the p38 MAPK signaling pathway. Caco-2 cells were cultured for 21 days and then stimulated with a cytokine mixture (CytoMix: TNF-alpha, interferon-gamma, and IL-1beta). Epithelial barrier function was evaluated by measuring permeability in an Ussing chamber. CytoMix-induced changes of MAPKs (p38, c-Jun amino-terminal kinase, and extracellular-regulated kinase), NO production, and inflammatory responses (IL-6 and IL-8 levels) were also assessed. The signaling pathways were further studied by pretreating cells with SB203580, a specific p38 MAPK inhibitor. CytoMix increased permeability at 24 and 48 h but not at 4 h. This was associated with increased IL-6 and IL-8 production, as well as increases in phosphorylation of all three MAPKs. Treatment with SB203580 completely blocked p38 activity with transient inhibition of p38 phosphorylation. SB203580 also prevented the CytoMix-induced permeability increase and reduced NO, IL-6, and IL-8 levels. The results suggest that p38 MAPK plays an important role in regulating epithelial barrier function during inflammation.
Wang
Quan
Q
Department of Research, Shriners Hospital for Children, Cincinnati OH 45229-3095, USA. wangqu@email.uc.edu
Guo
Xia-Ling
XL
Wells-Byrum
Denise
D
Noel
Greg
G
Pritts
Timothy A
TA
Ogle
Corn K
CK
D018938:Caco-2 Cells; D002463:Cell Membrane Permeability / Q000187:drug effects*; D016207:Cytokines / Q000494:pharmacology*; D004797:Enzyme-Linked Immunosorbent Assay; D004848:Epithelium / Q000378:metabolism*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007371:Interferon-gamma / Q000494:pharmacology; D007375:Interleukin-1 / Q000378:metabolism; D053583:Interleukin-1beta / Q000494:pharmacology; D015850:Interleukin-6 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011725:Pyridines / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism
D016207:Cytokines; D007093:Imidazoles; D007375:Interleukin-1; D053583:Interleukin-1beta; D015850:Interleukin-6; D016209:Interleukin-8; D011725:Pyridines; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D007371:Interferon-gamma; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580