Mitogen-activated protein kinase phosphatase 1 activity is necessary for oxidized phospholipids to induce monocyte chemotactic activity in human aortic endothelial cells.
Entrapment and oxidation of low density lipoproteins (LDL) in the sub-endothelial space is a key process in the initiation of atherosclerotic lesion development. Functional changes induced by oxidized lipids in endothelial cells are early events in the pathogenesis of atherosclerosis. Oxidized-l-alpha-1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (ox-PAPC), a major component of minimally modified/oxidized-LDL (MM-LDL) mimics the biological activities assigned to MM-LDL both in vitro in a co-culture model as well as in vivo in mice. We hypothesized that ox-PAPC initiates gene expression changes in endothelial cells that result in enhanced endothelial/monocyte interactions. To analyze the gene expression changes that oxidized lipids induce in endothelial cells, we used a suppression subtractive hybridization procedure to compare mRNA from PAPC-treated human aortic endothelial cells (HAEC) with that of ox-PAPC-treated cells. We report here the identification of a gene, mitogen-activated protein kinase phosphatase 1 (MKP-1), that is rapidly and transiently induced in ox-PAPC-treated HAEC. Inhibition of MKP-1 using either the phosphatase inhibitor sodium orthovanadate or antisense oligonucleotides prevents the accumulation of monocyte chemotactic activity in ox-PAPC-treated HAEC supernatants. Furthermore, we show that decreased monocyte chemotactic activity in HAEC treated with sodium orthovanadate or MKP-1 antisense oligonucleotides is due to decreased MCP-1 protein. Our results implicate a direct role for MKP-1 in ox-PAPC-induced signaling pathways that result in the production of MCP-1 protein by ox-PAPC-treated HAEC.
Reddy
S
S
Atherosclerosis Research Unit, Department of Medicine, University of California, Los Angeles, California 90095-1679, USA. sreddy@mednet.ucla.edu
Hama
S
S
Grijalva
V
V
Hassan
K
K
Mottahedeh
R
R
Hough
G
G
Wadleigh
D J
DJ
Navab
M
M
Fogelman
A M
AM
D001011:Aorta; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D018797:Cell Cycle Proteins; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000096:biosynthesis / Q000235:genetics*; D002634:Chemotaxis, Leukocyte / Q000187:drug effects* / Q000502:physiology; D018920:Coculture Techniques; D054638:Dual Specificity Phosphatase 1; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics* / Q000378:metabolism*; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D009000:Monocytes / Q000187:drug effects / Q000502:physiology*; D020319:Oligodeoxyribonucleotides, Antisense / Q000494:pharmacology; D010084:Oxidation-Reduction; D010713:Phosphatidylcholines / Q000494:pharmacology*; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D017027:Protein Tyrosine Phosphatases / Q000235:genetics* / Q000378:metabolism*; D014638:Vanadates / Q000494:pharmacology
D018797:Cell Cycle Proteins; D018932:Chemokine CCL2; D017874:Immediate-Early Proteins; D008077:Lipoproteins, LDL; D020319:Oligodeoxyribonucleotides, Antisense; D010713:Phosphatidylcholines; C099252:oxidized low density lipoprotein; D014638:Vanadates; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; C517019:DUSP1 protein, human; D054638:Dual Specificity Phosphatase 1; D017027:Protein Tyrosine Phosphatases