title: Protective role of oligomycin against intestinal epithelial barrier dysfunction caused by IFN-γ and TNF-α.
abstract: Although the precise mechanisms involved in intestinal barrier dysfunction induced by proinflammatory cytokines are incompletely understood, pharmacological restoration of barrier function is very important to the management of intestinal disease. This study was aimed to investigate the protective role of HIF-1α inhibitor oligomycin against intestinal epithelial barrier dysfunction induced by proinflammatory cytokines IFN-γ and TNF-α, and the underlying mechanisms. To induce barrier dysfunction, Caco-2 monolayers were treated with IFN-γ and TNF-α simultaneously. The cytokines-treated Caco-2 monolayers in the absence and in the presence of oligomycin were used for physiological, morphological, and biochemical analyses. The results showed that at the concentration of blocking HIF-1α activation, oligomycin significantly ameliorated TER reduction and paracellular permeability increase in Caco-2 monolayers challenged with IFN-γ and TNF-α. Oligomycin also largely attenuated the IFN-γ and TNF-α-related relocalization of tight junction proteins ZO-1 and occludin. Western blot analysis revealed that oligomycin abolished the increases of both MLC phosphorylation and MLCK protein expression induced by IFN-γ and TNF-α challenge. Quantitative RT-PCR analysis showed that oligomycin inhibited the IFN-γ and TNF-α-induced up-regulation of MLCK mRNA. It is concluded that oligomycin is able to attenuate intestinal epithelial barrier dysfunction induced by proinflammatory cytokines IFN-γ and TNF-α. The mechanism by which oligomycin protects intestinal barrier function may, at least in part, be attributed to block the up-regulated MLCK transcription and protein expression induced by IFN-γ and TNF-α.
authors.affiliation: State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Burn Research, Southwest Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Hang
authors.initials: H
authors.lastname: Liu
authors.forename: Pei
authors.initials: P
authors.lastname: Wang
authors.forename: Min
authors.initials: M
authors.lastname: Cao
authors.forename: Mu
authors.initials: M
authors.lastname: Li
authors.forename: Fengjun
authors.initials: F
authors.lastname: Wang
mesh_terms: D001483:Base Sequence; D015153:Blotting, Western; D018938:Caco-2 Cells; D017931:DNA Primers; D005455:Fluorescent Antibody Technique; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D007371:Interferon-gamma / Q000502:physiology*; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000201:enzymology / Q000503:physiopathology; D018994:Myosin Light Chains / Q000378:metabolism; D009219:Myosin-Light-Chain Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism; D009840:Oligomycins / Q000494:pharmacology*; D010766:Phosphorylation; D060888:Real-Time Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology*
chemical_list: D017931:DNA Primers; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D018994:Myosin Light Chains; D009840:Oligomycins; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma; D009219:Myosin-Light-Chain Kinase