Transcriptional regulation of inducible nitric oxide synthase by interleukin-1[beta] in cultured rat pulmonary artery smooth muscle cells. Wong, Hector R., Jonathan Finder, Karla Wasserloos, Charles J. Lowenstein, David A. Geller, Timothy R. Billiar, Bruce R. Pitt, and Paul Davies. Departments of Pharmacology; Anesthesiology/Critical Care Medicine, Division of Pediatric Critical Care Medicine; Pediatrics; and Surgery; University of Pittsburgh School of Medicine, Pittsburgh, PA 15261; and Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
APStracts 3:0046L, 1996.
Interleukin-1[beta] (IL-1[beta]) is the critical cytokine affecting peripheral vascular expression of inducible nitric oxide synthase (iNOS). Accordingly, we sought to determine a role for IL-1[beta] in stimulating iNOS transcription in cultured rat pulmonary artery smooth muscle cells (RPASMC). Treatment of RPASMC with IL-1[beta] caused a concentration-dependent increase in iNOS gene expression by Northern and Western blotting. To demonstrate IL-1[beta]-mediated transcriptional activation, we used transient liposome-mediated transfection of RPASMC with promoter-luciferase constructs containing deletional mutations of the murine macrophage iNOS 5_ flanking promoter region. IL-1[beta] increased promoter activity 2 to 3 fold over baseline in fragments ranging from -1592 (full-length) to -242 bp. Activity was lost, however, when the promoter fragment was shorter than -242 bp. IL-1[beta]-mediated increases in steady-state iNOS mRNA were sensitive to pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-_B activation. Nuclear proteins from IL-1[beta] -stimulated cells demonstrated PDTC-sensitive binding to an oligonucleotide containing the sequence for the NF-_B binding element present in the region between -242 and -42 bp. These data document that IL-1[beta], by itself, increases iNOS expression in RPASMC by transcriptional activation, mediated in part, by NF-_B. 

Received 2 August 1995; accepted in final form 20 February 1996.
APS Manuscript Number L242-5.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 1 April 96