Abstract
It was previously shown that cyclosporine A (CsA) increases transepithelial resistance in MDCK cells. Activation of the extracellular signal-regulated kinase 1/2 (ERK1/2) mitogen-activated protein kinase (MAPK) cascade seems to be pivotal to the CsA-induced increase in transepithelial electrical resistance (TER). This study examined the role played by TGF-beta in mediating the CsA-induced activation of ERK1/2 and the resulting increase in TER in MDCK cells. Paracellular permeability across MDCK monolayers after various treatments was assessed by measurement of TER. TGF-beta secretion was measured by Western blot and ELISA. Activation of the ERK1/2 pathway and tight junction protein expression were also assessed by Western blot analysis. CsA increased production and secretion of TGF-beta and expression of the TGF-beta receptor II. Exogenous addition of TGF-beta1 activated ERK1/2 and increased TER across MDCK monolayers, both of which were attenuated by the MEK inhibitor U0126. Neutralizing antibodies against TGF-beta1 and the TGF-beta receptor II significantly reduced the CsA-induced increase in TER. Both CsA and TGF-beta1 increased expression of tight junction proteins claudin-1 and zonula occludens 2. Inhibition of the p38 MAPK pathway also attenuated the TGF-beta1-induced increase in TER. The results presented here suggest that the CsA-induced modulation of paracellular permeability may be mediated, at least in part, by an increase in TGF-beta production.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Antibodies / pharmacology
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Butadienes / pharmacology
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Cell Division / drug effects
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Cell Survival / drug effects
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Cyclosporine / pharmacology*
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Dextrans / pharmacokinetics
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Dogs
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Electric Impedance
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Enzyme Inhibitors / pharmacology
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Epithelial Cells / drug effects*
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Epithelial Cells / metabolism*
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Fluorescein-5-isothiocyanate / analogs & derivatives
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Fluorescein-5-isothiocyanate / pharmacokinetics
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Imidazoles / pharmacology
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Immunosuppressive Agents / pharmacology*
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Kidney / cytology
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MAP Kinase Kinase Kinases / antagonists & inhibitors
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MAP Kinase Kinase Kinases / metabolism
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MAP Kinase Signaling System / drug effects
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MAP Kinase Signaling System / physiology
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Mitogen-Activated Protein Kinase 1 / antagonists & inhibitors
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Mitogen-Activated Protein Kinase 1 / metabolism
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Mitogen-Activated Protein Kinase 3 / antagonists & inhibitors
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Mitogen-Activated Protein Kinase 3 / metabolism
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Nitriles / pharmacology
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Protein Serine-Threonine Kinases / metabolism
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Pyridines / pharmacology
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Receptor, Transforming Growth Factor-beta Type II
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Receptors, Transforming Growth Factor beta / metabolism
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Tight Junctions / drug effects
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Tight Junctions / metabolism
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Transforming Growth Factor beta1 / immunology
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Transforming Growth Factor beta1 / metabolism*
Substances
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Antibodies
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Butadienes
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Dextrans
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Enzyme Inhibitors
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Imidazoles
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Immunosuppressive Agents
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Nitriles
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Pyridines
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Receptors, Transforming Growth Factor beta
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Transforming Growth Factor beta1
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U 0126
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fluorescein isothiocyanate dextran
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Cyclosporine
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Protein Serine-Threonine Kinases
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Mitogen-Activated Protein Kinase 1
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Mitogen-Activated Protein Kinase 3
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MAP Kinase Kinase Kinases
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Receptor, Transforming Growth Factor-beta Type II
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Fluorescein-5-isothiocyanate
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SB 203580