The role of p38 MAP kinase in hydrogen peroxide mediated endothelial solute permeability.
OBJECTIVE
The purpose of this study was to determine the contribution of p38 MAP kinase activity during hydrogen peroxide mediated increased endothelial solute permeability. We also sought to identify the role of p38 MAP kinase-mediated changes in endothelial cell architecture due to hydrogen peroxide challenge.


METHODS
Hydrogen peroxide mediated permeability of HUVEC was determined with and without inhibition of p38 MAP kinase by SB202190. Hydrogen peroxide mediated rearrangement of the endothelial actin cytoskeleton and junctional proteins occludin and ZO-1 were observed by immunofluorescence microscopy.


RESULTS
Hydrogen peroxide treatment of endothelial monolayers caused a significant increase in solute permeability over a ninety-minute time period. Oxidant-mediated permeability and phosphorylation of p38 MAP kinase was significantly attenuated by SB 202190. Immunofluorescent staining for the tight junctional proteins occludin and ZO-1 demonstrated that oxidant challenge caused a loss of endothelial tight junction organization. Rhodamine phalloidin staining of the actin cytoskeleton showed that hydrogen peroxide stimulated increased stress fiber formation with concomitant gap formation between adjacent endothelial cells. Inhibition of p38 MAP kinase during oxidant challenge significantly attenuated actin stress fiber formation and prevented gap formation.


CONCLUSIONS
These data demonstrate that p38 MAP kinase activity is involved in hydrogen peroxide mediated permeability, stress fiber formation, and intracellular gap formation.
Kevil
C G
CG
Department of Molecular and Cellular Physiology, LSU Health Sciences Center, Shreveport, LA 71130, USA.
Oshima
T
T
Alexander
J S
JS
D008841:Actin Cytoskeleton / Q000187:drug effects / Q000648:ultrastructure; D000199:Actins / Q000378:metabolism; D015153:Blotting, Western; D002463:Cell Membrane Permeability / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology / Q000648:ultrastructure; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007093:Imidazoles / Q000494:pharmacology; D008565:Membrane Proteins / Q000032:analysis / Q000276:immunology; D008856:Microscopy, Fluorescence; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D062793:Occludin; D010750:Phosphoproteins / Q000032:analysis / Q000276:immunology; D010766:Phosphorylation; D011725:Pyridines / Q000494:pharmacology; D019108:Tight Junctions / Q000187:drug effects / Q000648:ultrastructure; D013997:Time Factors; D014471:Umbilical Veins / Q000166:cytology; D062826:Zonula Occludens-1 Protein; D048051:p38 Mitogen-Activated Protein Kinases
D000199:Actins; D004791:Enzyme Inhibitors; D007093:Imidazoles; D008565:Membrane Proteins; C568985:OCLN protein, human; D062793:Occludin; D010750:Phosphoproteins; D011725:Pyridines; C569042:TJP1 protein, human; D062826:Zonula Occludens-1 Protein; D006861:Hydrogen Peroxide; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C090942:4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)imidazole