Induction of Vascular Endothelial Growth Factor Gene Expression by Interleukin-1 in Rat Aortic Smooth Muscle Cells

doi:10.1074/jbc.270.1.308

Induction of Vascular Endothelial Growth Factor Gene Expression by Interleukin-1 in Rat Aortic Smooth Muscle Cells (*)

From the (1)Cardiovascular Biology Laboratory, Harvard School of Public Health, the Department of Medicine, Harvard Medical School and the
(2)Pulmonary andCardiovascular Divisions, Brigham and Women's Hospital, Boston, Massachusetts 02115

** Supported by a Clinician Scientist Award and a Grant-in-Aid from the American Heart Association, with funds contributed in part by the AHA, Massachusetts Affiliate. To whom all correspondence should be addressed:
Cardiovascular Biology Laboratory, Harvard School of Public Health, 677 Huntington Ave., Boston, MA 02115
.

Abstract

Vascular endothelial growth factor (VEGF) is a potent and specific mitogen for vascular endothelial cells and promotes neovascularization in vivo. To determine whether interleukin-1β (IL-1β), which is present in atherosclerotic lesions, induces VEGF gene expression in vascular smooth muscle cells, we performed RNA blot analysis on rat aortic smooth muscle cells (RASMC) with a rat VEGF cDNA probe. IL-1β increased VEGF mRNA levels in RASMC in a time- and dose-dependent manner. As little as 0.1 ng/ml IL-1β increased VEGF mRNA levels by 2-fold and 10 ng/ml IL-1β increased VEGF mRNA by 4-fold. We also measured the half-life of VEGF mRNA and performed nuclear run-on experiments before and after addition of IL-1β to see if IL-1β increased VEGF mRNA levels by stabilizing the mRNA or by increasing its rate of transcription. The normal, 2-h half-life of VEGF mRNA in RASMC was lengthened to 3.2 h (60%) by IL-1β, and IL-1β increased the rate of VEGF gene transcription by 2.1-fold. In immunoblot experiments with an antibody specific for VEGF, we found that IL-1β increased VEGF protein levels in RASMC by 3.3-fold. Together these data indicate that IL-1β induces VEGF gene expression in smooth muscle cells. This IL-1β-induced expression of VEGF may accelerate the progression of atherosclerotic lesions by promoting the development of new blood vessels.

Footnotes

↵^§ Contributed equally to this work.
↵^¶ Supported by a National Research Service Award from the National Institutes of Health.
↵* This work was supported in part by a grant from Bristol-Myers Squibb. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

VEGF

vascular endothelial growth factor

IL-1β

interleukin-1β

RASMC

rat aortic smooth muscle cells

GAPDH

glyceraldehyde-3-phosphate dehydrogenase

TNF

tumor necrosis factor

EGF

epidermal growth factor

TGF

transforming growth factor

PDGF

platelet-derived growth factor

AII

angiotensin II.
- Received August 17, 1994.
- Revision received October 16, 1994.