Abstract
In vascular smooth muscle, increased expression of cyclooxygenase-2 (COX-2) has emerged as an important mechanism for regulation of prostanoid synthesis influenced by vessel injury, cytokines, and growth factors. We have investigated how COX-2 participates in angiotensin II (ANG II)-mediated cell responses in cultured human vascular smooth muscle cells (VSMCs). ANG II type 1 (AT1) receptors induce increased accumulation of COX-2, both at the mRNA and protein levels. ANG II increased transcription of the COX-2 gene; also, nuclear extracts from stimulated cells had increased NF-κ B binding to its DNA consensus sequence. ANG II-induced COX-2 expression was markedly blunted by inhibition of mitogen-activated protein kinase. Furthermore, the ANG II-induced increase in COX-2 protein abundance was attenuated by both the peroxisome proliferator-activated receptor α (PPARα) activator Wy-14,643 [pyrinixic acid; 4-chloro-6-(2,3-xylidino)-2-pyrimidinyl) thioacetic acid] and the PPARγ activator 15d-PGJ2 (15-deoxy-Δ12–14-prostaglandin J2). Not only did ANG II increase COX-2 expression and prostaglandin synthesis, ANG II-stimulated DNA synthesis and cell migration were dependent on COX-2 activity. PPARα and PPARγ activators inhibited ANG II-stimulated DNA synthesis and cell migration. These results suggest that ANG II enhances COX-2 expression at the transcription level; also, COX-2 activity plays an important role in mediating ANG II- induced proliferation and migration of VSMCs, suggesting the possibility of magnification of ANG II effects over time due to the induction of COX-2 expression. These results also demonstrate that both the α and γ type of PPAR activators inhibit COX-2 expression induced by angiotensin II in VSMCs which may have therapeutic significance in vascular diseases.
Footnotes
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↵1 Current address: Epidauros Biotechnologie AG, Munich, Germany.
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This work was supported by a grant from the National Institutes of Health (HL41315) and the Research Service of the VA Health Care System. R.K. was supported by the Association of Clinical Pharmacology Berlin/Brandenburg and the German Ministry for Education, Research, and Technology, as well as a Dean's postdoctoral fellowship from Stanford University. T.W.-L. is a fellow of the clinical pharmacology training program at Stanford University (National Institutes of Health Grant GM07065).
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DOI: 10.1124/jpet.102.037705
- Abbreviations:
- VSMC
- vascular smooth muscle cell
- ANG II
- angiotensin II
- AT1
- ANG II type 1
- PLA2
- phospholipase A2
- MAP
- mitogen-activated protein
- PI
- phosphatidylinositol
- PG
- prostaglandin
- AA
- arachidonic acid
- COX
- cyclooxygenase
- PPAR
- peroxisome proliferation-activated receptor
- Wy-14,643
- pyrinixic acid [4-chloro-6-(2,3-xylidino)-2-pyrimidinyl)thioacetic acid]
- ATK
- arachidonyl trifluoromethyl ketone
- PDGF
- platelet-derived growth factor
- PDGF-BB
- PDGF-B subunit homodimer
- PCR
- polymerase chain reaction
- bp
- base pair(s)
- SSC
- standard saline citrate
- CREB
- cAMP response element-binding protein
- SP1
- simian virus 40 promoter factor 1
- NF-κB
- nuclear factor-κB
- PAGE
- polyacrylamide gel electrophoresis
- ELISA
- enzyme-linked immunosorbent assay
- DMEM
- Dulbecco's modified Eagle's medium
- HPF
- high-powered microscope field
- PD123319
- S-(+)-1-([4-dimethylamino)-3-methylphenyl]methyl)-5-(diphenylacetyl)-4,5,6,7-tetrahydro-1H-imidazo (4,5-c)pyridine-6-carboxylic acid
- PD98059
- 2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one
- SB203580
- 4-(4-fluorophenyl)-2(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole
- AG490
- α-cyano-(3,4-dihydroxy)-N-benzylcinnamide
- LY294,002
- 2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride
- BAPTA
- 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid
- GF109203X
- 3-[1-[3-(dimethylamino) propyl]-1H-indol-3-yl]-4-(1H-indol-3-yl)-1H-pyrrole-2,5-dione
- NS-398
- N-(2-[cyclohexyloxy]-4-nitrophenyl)methanesulfonamide
- EGF
- epidermal growth factor
- cPLA2
- cytosolic PLA2
- Received April 25, 2002.
- Accepted August 13, 2002.
- U.S. Government
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