Calcitonin gene-related peptide receptor activation by receptor activity-modifying protein-1 gene transfer to vascular smooth muscle cells

Endocrinology. 2006 Apr;147(4):1932-40. doi: 10.1210/en.2005-0918. Epub 2005 Dec 22.


The neuropeptide calcitonin gene-related peptide (CGRP) is a potent vasodilator that plays a protective role in the cardiovascular system. The receptor for CGRP is an unusual complex of the G protein-coupled calcitonin-like receptor and an obligate receptor activity modifying protein-1 (RAMP1). In this report we provide the first evidence that RAMP1 is rate limiting in vascular smooth muscle cells. Although cultured rat aorta smooth muscle cells express calcitonin like-receptor and RAMP1, we found that CGRP is not a potent activator of the receptor. After overexpression of RAMP1 by adenoviral gene transfer, there was a striking increase in CGRP-induced production of cAMP, with a 75-fold decrease in the EC(50) and a 1.5-fold increase in the maximal response. The biological consequence of this increased receptor activity was observed in three different paradigms. First, RAMP1 gene transfer caused a CGRP-dependent decrease in cell proliferation. Second, RAMP1 and CGRP treatment led to a 3-fold greater free radical-induced reduction in cell number. Finally, RAMP1 gene transfer resulted in a 5-fold CGRP-dependent increase in terminal deoxynucleotidyltransferase-mediated deoxyuridine triphosphate nick end labeling-positive apoptotic cells upon serum withdrawal. The mechanisms underlying these effects involved cAMP-dependent pathways. We propose that RAMP1 gene transfer may be an effective strategy for increasing the effectiveness of CGRP-induced decrease in restenosis after aortic angioplasty.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoviridae / genetics
  • Animals
  • Apoptosis
  • Calcitonin Receptor-Like Protein
  • Cell Proliferation
  • Cells, Cultured
  • Cyclic AMP / biosynthesis
  • Gene Transfer, Horizontal
  • Genetic Therapy*
  • Humans
  • Intracellular Signaling Peptides and Proteins / genetics*
  • Male
  • Membrane Proteins / genetics*
  • Muscle, Smooth, Vascular / cytology
  • Muscle, Smooth, Vascular / metabolism*
  • Myocytes, Smooth Muscle / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Receptor Activity-Modifying Protein 1
  • Receptor Activity-Modifying Proteins
  • Receptors, Calcitonin / physiology
  • Receptors, Calcitonin Gene-Related Peptide / physiology*


  • CALCRL protein, human
  • Calcitonin Receptor-Like Protein
  • Intracellular Signaling Peptides and Proteins
  • Membrane Proteins
  • RAMP1 protein, human
  • Ramp1 protein, rat
  • Receptor Activity-Modifying Protein 1
  • Receptor Activity-Modifying Proteins
  • Receptors, Calcitonin
  • Receptors, Calcitonin Gene-Related Peptide
  • Cyclic AMP