Present address: Clinical and Molecular Genetics Unit, UCL Institute of Child Health, London, UK.
Endosomal proteolysis regulates calcitonin gene-related peptide responses in mesenteric arteries
Article first published online: 29 NOV 2012
© 2012 The Authors. British Journal of Pharmacology © 2012 The British Pharmacological Society
British Journal of Pharmacology
Special Issue: Themed Section: Cannabinoids 2012. Guest Editor: Stephen PH Alexander
Volume 167, Issue 8, pages 1679–1690, December 2012
How to Cite
McNeish, A., Roux, B., Aylett, S.-B., Van Den Brink, A. and Cottrell, G. (2012), Endosomal proteolysis regulates calcitonin gene-related peptide responses in mesenteric arteries. British Journal of Pharmacology, 167: 1679–1690. doi: 10.1111/j.1476-5381.2012.02129.x
- Issue published online: 29 NOV 2012
- Article first published online: 29 NOV 2012
- Accepted manuscript online: 6 AUG 2012 07:29AM EST
- Manuscript Accepted: 17 JUN 2012
- Manuscript Revised: 11 JUN 2012
- Manuscript Received: 20 MAR 2012
- calcitonin gene-related peptide;
- calcitonin receptor-like receptor;
- receptor activity-modifying protein;
- endothelin-converting enzyme-1;
- smooth muscle cell;
Background and Purpose
Calcitonin gene-related peptide (CGRP) is a potent vasodilator, implicated in the pathogenesis of migraine. CGRP activates a receptor complex comprising, calcitonin receptor-like receptor (CLR) and receptor activity-modifying protein 1 (RAMP1). In vitro studies indicate recycling of CLR●RAMP1 is regulated by degradation of CGRP in early endosomes by endothelin-converting enzyme-1 (ECE-1). However, it is not known if ECE-1 regulates the resensitization of CGRP-induced responses in functional arterial tissue.
CLR, ECE-1a-d and RAMP1 expression in rat mesenteric artery smooth muscle cells (RMA-SMCs) and mesenteric arteries was analysed by RT-PCR and by immunofluorescence and confocal microscopy. CGRP-induced signalling in cells was examined by measuring cAMP production and ERK activation. CGRP-induced relaxation of arteries was measured by isometric wire myography. ECE-1 was inhibited using the specific inhibitor, SM-19712.
RMA-SMCs and arteries contained mRNA for CLR, ECE-1a-d and RAMP1. ECE-1 was present in early endosomes of RMA-SMCs and in the smooth muscle layer of arteries. CGRP induced endothelium-independent relaxation of arteries. ECE-1 inhibition had no effect on initial CGRP-induced responses but reduced cAMP generation in RMA-SMCs and vasodilation in mesenteric arteries responses to subsequent CGRP challenges.
Conclusions And Implications
ECE-1 regulated the resensitization of responses to CGRP in RMA-SMCs and mesenteric arteries. CGRP-induced relaxation did not involve endothelium-derived pathways. This is the first report of ECE-1 regulating CGRP responses in SMCs and arteries. ECE-1 inhibitors may attenuate an important vasodilatory pathway, implicated in primary headaches and may represent a new therapeutic approach for the treatment of migraine.