Regulation of c-Jun N-terminal kinase and p38 kinase pathways in endothelial cells.
The rapid and transient induction of E-selectin gene expression by inflammatory tumor necrosis factor (TNF)-alpha in endothelial cells is mediated by signaling pathways which involve c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) kinase pathways. To explore this regulation, we first observed that in the continuous presence of cytokine TNF, activation of JNK-1 in both nuclear and cytoplasmic compartments peaked at 15-30 min, with activity returning to uninduced levels by 60 min. Phosphorylation of both the p38 kinase and its molecular target, the nuclear transcription factor, activating transcription factor-2, were transient after TNF-alpha or interleukin (IL)-1beta induction. However, cycloheximide treatment prolonged the TNF-alpha-induced JNK-1 kinase activity beyond 60 min, suggesting that protein synthesis is required to limit this signaling cascade. We investigated the possible role of the dual-specificity phosphatases MAPK phosphatase (MKP)-1 and MKP-2 in limiting cytokine-induced MAPK signaling. Maximum induction of MKP-1 mRNA and nuclear protein levels by TNF-alpha or IL-1beta were noted at 60 min and their expression correlated with the termination of JNK kinase activity, whereas nuclear levels of MKP-2 were not significantly affected by treatment with TNF-alpha or IL-1beta. Transient overexpression of MKP-1 demonstrated significant specific inhibition of E-selectin promoter activity consistent with a regulatory role for dual-specificity phosphatases. Inhibition of MKP-1 expression through the use of small interfering RNAs prolonged the cytokine-induced p38 and JNK kinase phosphorylation. Our results suggest that endogenous inhibitors of the MAPK cascade, such as the dual-specificity phosphatases like MKP-1 may be important for the postinduction repression of MAPK activity and E-selectin transcription in endothelial cells. Thus, these inhibitors may play an important role in limiting the inflammatory effects of TNF-alpha and IL-1beta.
Wadgaonkar
Raj
R
Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA. raj.wadgaonkar@downstate.edu
Pierce
Jacqueline W
JW
Somnay
Kaumudi
K
Damico
Rachel L
RL
Crow
Michael T
MT
Collins
Tucker
T
Garcia
Joe G N
JG
D000970:Antineoplastic Agents / Q000494:pharmacology; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D003593:Cytoplasm / Q000378:metabolism; D054638:Dual Specificity Phosphatase 1; D054637:Dual-Specificity Phosphatases; D019040:E-Selectin / Q000235:genetics* / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics / Q000378:metabolism; D007375:Interleukin-1 / Q000378:metabolism / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases; D008156:Luciferases; D054639:Mitogen-Activated Protein Kinase Phosphatases; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D011401:Promoter Regions, Genetic / Q000235:genetics; D054645:Protein Phosphatase 1; D011500:Protein Synthesis Inhibitors; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014471:Umbilical Veins; D048051:p38 Mitogen-Activated Protein Kinases
D000970:Antineoplastic Agents; D018797:Cell Cycle Proteins; D019040:E-Selectin; D004791:Enzyme Inhibitors; D017874:Immediate-Early Proteins; D007375:Interleukin-1; D011500:Protein Synthesis Inhibitors; D034741:RNA, Small Interfering; D014409:Tumor Necrosis Factor-alpha; D003513:Cycloheximide; D008156:Luciferases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D054639:Mitogen-Activated Protein Kinase Phosphatases; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; C517019:DUSP1 protein, human; C490583:DUSP4 protein, human; D054638:Dual Specificity Phosphatase 1; D054637:Dual-Specificity Phosphatases; D017027:Protein Tyrosine Phosphatases