title: Inhibition of p38 MAPK activation via induction of MKP-1: atrial natriuretic peptide reduces TNF-alpha-induced actin polymerization and endothelial permeability.
abstract: The atrial natriuretic peptide (ANP) is a cardiovascular hormone possessing antiinflammatory potential due to its inhibitory action on the production of inflammatory mediators, such as tumor necrosis factor-alpha (TNF-alpha). The aim of this study was to determine whether ANP is able to attenuate inflammatory effects of TNF-alpha on target cells. Human umbilical vein endothelial cells (HUVECs) were treated with TNF-alpha in the presence or absence of ANP. Changes in permeability, cytoskeletal alterations, phosphorylation of p38 MAPK and HSP27, and expression of MKP-1 were determined by macromolecule permeability assay, fluorescence labeling, RT-PCR, and immunoblotting. Antisense studies were done by transfecting cells with MKP-1 antisense oligonucleotides. Activation of HUVECs with TNF-alpha lead to a significant increase of macromolecule permeability and formation of stress fibers. Treatment of cells with ANP (10(-8) to 10(-6) mol/L) significantly reduced the formation of stress fibers and elevated permeability. Both TNF-alpha-induced effects were shown to be mediated via the activation of p38 using SB203580, a specific inhibitor of p38. ANP significantly reduced the TNF-alpha-induced activation of p38 and attenuated the phosphorylation of HSP27, a central target downstream of p38. ANP showed no effect on p38 upstream kinases MKK3/6. However, a significant induction of the MAPK phosphatase MKP-1 mRNA and protein could be observed in ANP-treated cells. Antisense experiments proved a causal role for MKP-1 induction in the ANP-mediated inhibition of p38. These data show the inhibitory action of ANP on TNF-alpha-induced changes in endothelial cytoskeleton and macromolecule permeability involving an MKP-1-induced inactivation of p38 MAPK. These effects point to an antiinflammatory and antiatherogenic potential of this cardiovascular hormone.
authors: Department of Pharmacy, Center of Drug Research, University of Munich, Munich, Germany. Alexandra.Kiemer@ cup.uni-muenchen.de
authors: Alexandra K
authors: AK
authors: Kiemer
authors: Nina C
authors: NC
authors: Weber
authors: Robert
authors: R
authors: Fürst
authors: Nicole
authors: N
authors: Bildner
authors: Stefanie
authors: S
authors: Kulhanek-Heinze
authors: Angelika M
authors: AM
authors: Vollmar
mesh_terms: D000199:Actins / Q000378:metabolism*; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D018797:Cell Cycle Proteins; D002463:Cell Membrane Permeability / Q000187:drug effects; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000502:physiology; D054638:Dual Specificity Phosphatase 1; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D004789:Enzyme Activation; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D017874:Immediate-Early Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D007700:Kinetics; D020935:MAP Kinase Signaling System; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors*; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D017027:Protein Tyrosine Phosphatases / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis; D022502:Stress Fibers / Q000378:metabolism / Q000648:ultrastructure; D015533:Transcriptional Activation; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D000199:Actins; D018797:Cell Cycle Proteins; D006360:Heat-Shock Proteins; D017874:Immediate-Early Proteins; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D009320:Atrial Natriuretic Factor; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; C517019:DUSP1 protein, human; D054638:Dual Specificity Phosphatase 1; D017027:Protein Tyrosine Phosphatases; D006152:Cyclic GMP