Lung epithelial barrier function and wound healing are decreased by IL-4 and IL-13 and enhanced by IFN-gamma.
To understand the effects of cytokines on epithelial cells in asthma, we have investigated the effects of interleukin (IL)-4, IL-13, and interferon (IFN)-gamma on barrier function and wound healing in Calu-3 human lung epithelial cells. IL-4 and IL-13 treatment of Calu-3 cells grown on Transwell filters resulted in a 70-75% decrease in barrier function as assessed by electrophysiological and [(14)C]mannitol flux measurements. In contrast, IFN-gamma enhanced barrier function threefold using these same parameters. Cells treated concurrently with IFN-gamma and IL-4 or IL-13 showed an initial decline in barrier function that was reversed within 2 days, resulting in barrier levels comparable to control cells. Analysis of the tight junction-associated proteins ZO-1 and occludin showed that IL-4 and IL-13 significantly reduced ZO-1 expression and modestly decreased occludin expression compared with controls. IFN-gamma, quite unexpectedly given its enhancing effect on barrier function, reduced expression of ZO-1 and occludin to almost undetectable levels compared with controls. In wound-healing assays of cells grown on collagen I, IL-4 and IL-13 decreased migration, whereas IFN-gamma treatment enhanced migration, compared with control cells. Addition of IFN-gamma, in combination with IL-4 or IL-13, restored migration of cells to control levels. Migration differences observed between the various cytokine treatments was correlated with expression of the collagen I-binding alpha(2)beta(1)-integrin at the leading edge of cells at the wound front; alpha(2)beta(1)-integrin expression was decreased in IFN-gamma-treated cells compared with controls, whereas it was highest in IL-4- and IL-13-treated cells. These results demonstrate that IL-4 and IL-13 diminish the capacity of Calu-3 cells to maintain barrier function and repair wounds, whereas IFN-gamma promotes epithelial restitution by enhancing barrier function and wound healing.
Ahdieh
M
M
Department of Biomolecular Screening, Immunex Corporation, Seattle, Washington 98101, USA.
Vandenbos
T
T
Youakim
A
A
D001249:Asthma / Q000276:immunology / Q000503:physiopathology; D001692:Biological Transport; D015824:Blood-Air Barrier / Q000502:physiology*; D015820:Cadherins / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology; D006801:Humans; D016023:Integrins / Q000378:metabolism; D007371:Interferon-gamma / Q000378:metabolism*; D018793:Interleukin-13 / Q000494:pharmacology*; D015847:Interleukin-4 / Q000494:pharmacology*; D008168:Lung / Q000187:drug effects / Q000502:physiology*; D008353:Mannitol / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D018613:Microscopy, Confocal; D062793:Occludin; D010750:Phosphoproteins / Q000378:metabolism; D038981:Receptors, Collagen; D019948:Receptors, Interleukin-4 / Q000378:metabolism; D020545:Respiratory Mucosa / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D014407:Tumor Cells, Cultured; D014945:Wound Healing / Q000502:physiology*; D062826:Zonula Occludens-1 Protein
D015820:Cadherins; D016023:Integrins; D018793:Interleukin-13; D008565:Membrane Proteins; C568985:OCLN protein, human; D062793:Occludin; D010750:Phosphoproteins; D038981:Receptors, Collagen; D019948:Receptors, Interleukin-4; C569042:TJP1 protein, human; D062826:Zonula Occludens-1 Protein; D015847:Interleukin-4; D008353:Mannitol; D007371:Interferon-gamma