Cyclosporin A Selectively Inhibits Mitogen-Induced Cyclooxygenase-2 Gene Transcription in Vascular Smooth Muscle Cells
- 1Department of Pharmacology, Emory University School of Medicine (A.M.R., K.X., M.L.E., T.J.M.), and the 2Program in Molecular and Systems Pharmacology, Graduate Division of Biological and Biomedical Sciences, Emory University (A.M.R., T.J.M.), Atlanta, Georgia
Abstract
The prostaglandin synthase cyclooxygenase-2 (COX-2) is produced by an immediate early response gene induced in most cells by a variety of stimuli. Several studies have shown that the immunosuppressant cyclosporin (CsA) interferes with prostanoid metabolism, but the mechanisms are unclear. Here we examine the effect of CsA on COX-2 mRNA induction in cultured rat vascular smooth muscle cells (VSMC) that natively express the nuclear factor of activated T-cells, a known mediator of CsA-sensitive transcription. CsA significantly suppresses strong COX-2 mRNA induction caused by the Ca2+-mobilizing mitogens UTP, angiotensin II, and platelet-derived growth factor-BB, and the synergistic induction caused by costimulation with ionomycin and a phorbol ester. Forskolin and interleukin-1β are substantially weaker COX-2 mRNA inducers, and CsA does not inhibit their effect. CsA strongly inhibits UTP-, angiotensin II-, and platelet-derived growth factor-BB-stimulated COX-2 gene transcription as measured by nuclear run-on or promoter-reporter studies, but has no effect on mRNA induction caused by post-transcriptional stabilization of a distal COX-2 mRNA 3′-untranslated region regulatory element. These data show that CsA selectively inhibits mitogen-induced COX-2 gene expression by a transcriptional mechanism that may involve the nuclear factor of activated T-cells.
Footnotes
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Send reprint requests to: T. J. Murphy, Ph.D., Department of Pharmacology, Emory University School of Medicine, 5031 O.W. Rollins Research Bldg., Atlanta, GA 30322. E-mail:medtjm{at}bimcore.emory.edu
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Supported by Grants HL52810 and HL56107 from the National Heart Lung and Blood Institute. T.J.M. is an established investigator of the American Heart Association. A.M.R. is supported by a predoctoral training grant (GM08602-03).
- Abbreviations:
- COX-2
- cyclooxygenase-2
- CsA
- cyclosporin A
- NFAT
- nuclear factor of activated T-cells
- VSMC
- vascular smooth muscle cells
- PDGF-BB
- platelet-derived growth factor-BB
- RPA
- RNase protection assay
- AP1
- activator protein 1
- SRE
- serum response element
- NFκB
- nuclear factor-κB
- kb
- kilobase pairs
- PMA
- phorbol 12-myristate 13-acetate
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- Received March 3, 2000.
- Accepted June 21, 2000.
- The American Society for Pharmacology and Experimental Therapeutics
