Dexamethasone Increases RAMP1 and CRLR mRNA Expressions in Human Vascular Smooth Muscle Cells

doi:10.1006/bbrc.2000.2552

Biochemical and Biophysical Research Communications

Volume 270, Issue 3, 21 April 2000, Pages 1063-1067

https://doi.org/10.1006/bbrc.2000.2552 Get rights and content

Abstract

A recent report has shown that in vitro the RAMP2/CRLR complex is a functional adrenomedullin receptor in human endothelial and vascular smooth muscle cells. However, in vivo, it is well known that CGRP receptors are expressed in human coronary arteries and that a beneficial effect is observed in patients after CGRP infusion of patients with congestive cardiac failure. This contrast may be explained by the in vivo impregnation of major hormones, so we have tested if glucocorticoids were able in vitro to enhance the expression of the RAMP1/CRLR expression leading to functional CGRP receptors. The expression of RAMP1, RAMP2, CRLR, and adrenomedullin was evaluated by semiquantitative reverse-transcriptase polymerase chain reaction (RT-PCR) using ³³P in human coronary arteries vascular smooth muscle cells (VSMC) cultured in the presence of dexamethasone. Under basal conditions, the CRLR mRNA was expressed, but RAMP2 mRNA was clearly more abundant than RAMP1 mRNA. Increases in CRLR and RAMP1 mRNA expressions occurred 4 h after treatment of VSMC with 10⁻⁷ M dexamethasone and no change was found for RAMP2 mRNA. Adrenomedullin mRNA increased later, i.e., 8 and 16 h after dexamethasone treatment. The RAMP1 mRNA expression was elevated with doses of dexamethasone ranging from 10⁻¹⁰ to 10⁻⁷ M, thus a 5-fold increase in the ratio between RAMP1 and RAMP2 was observed with the lowest dose of dexamethasone and a 2-fold rise at 10⁻⁷ M. CRLR mRNA levels were half-reduced with the two lowest doses of dexamethasone (10⁻¹⁰ and 10⁻⁹ M), but increased from 10⁻⁸ to 10⁻⁷ M. Thus, we suggest that, in vivo, glucocorticoids are involved in the expression of CGRP receptors by human coronary VSMC.

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Citation Excerpt :
During the first cycle, the 94 °C step was extended to 5 min, and on final cycle the 72 °C step was extended to 5 min. Control reactions were carried out as previously described [5] in a T Gradient Thermocycler 96 (Biometra, Vysis, Voisins le Bretonneux, France). In some experiments, amplified products were analyzed by electrophoresis in 2% agarose gels and visualized by ethidium bromide.
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Regular ArticleDexamethasone Increases RAMP1 and CRLR mRNA Expressions in Human Vascular Smooth Muscle Cells

Abstract

FEBS Lett.

Biochem. Biophys. Res. Commun.

Biochem. Biophys. Res. Commun.

Biochem. Biophys. Res. Comunm.

Eur. J. Pharmacol.

Anal. Biochem.

Regular Article
Dexamethasone Increases RAMP1 and CRLR mRNA Expressions in Human Vascular Smooth Muscle Cells