CGRP1 receptor activation induces piecemeal release of protease‐1 from mouse bone marrow‐derived mucosal mast cells

• Published in: Neurogastroenterology and motility Vol. 23; no. 2; pp. e57 - e68
• Main Authors: Rychter, J. W., Van nassauw, L., Timmermans, J.‐P., Akkermans, L. M. A., Westerink, R. H. S., Kroese, A. B. A.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.02.2011
• Subjects: Animals; beta N- double prime Acetylhexosaminidase; beta-N-Acetylhexosaminidases - metabolism; BIBN4096BS; Bone marrow; Bone Marrow - metabolism; Ca2+ imaging; Calcitonin gene-related peptide; Calcitonin Gene-Related Peptide Receptor Antagonists; Calcium (intracellular); Calcium - metabolism; Calcium influx; Calcium mobilization; Cells, Cultured; Chymases - metabolism; Dose-Response Relationship, Drug; Fibers; immunocyto‐chemistry; Inflammation; Male; Mast cells; Mast Cells - cytology; Mast Cells - metabolism; Mice; Mice, Inbred BALB C; mouse mast cell protease‐1 release; Mucosa; mucosal mast cell activation; Nerves; Neuropeptides; Piperazines - pharmacology; Quinazolines - pharmacology; Receptor activity modifying proteins; Receptor mechanisms; Receptors, Calcitonin Gene-Related Peptide - metabolism; Sensory neurons; Signal Transduction - physiology
• ISSN: 1350-1925; 1365-2982
• DOI: 10.1111/j.1365-2982.2010.01617.x

Background  The parasitized or inflamed gastrointestinal mucosa shows an increase in the number of mucosal mast cells (MMC) and the density of extrinsic primary afferent nerve fibers containing the neuropeptide, calcitonin gene‐related peptide (CGRP). Currently, the mode of action of CGRP on MMC is unknown. Methods  The effects of CGRP on mouse bone marrow‐derived mucosal mast cells (BMMC) were investigated by measurements of intracellular Ca2+ [Ca2+]i and release of mMCP‐1. Key Results  Bone marrow‐derived mucosal mast cells responded to the application of CGRP with a single transient rise in [Ca2+]i. The proportion of responding cells increased concentration‐dependently to a maximum of 19 ± 4% at 10−5 mol L−1 (mean ±SEM; C48/80 100%; EC50 10−8 mol L−1). Preincubation with the CGRP receptor antagonist BIBN4096BS (10−5 mol L−1) completely inhibited BMMC activation by CGRP [range 10−5 to 10−11 mol L−1; analysis of variance (anova)P < 0.001], while preincubation with LaCl3 to block Ca2+ entry did not affect the response (P = 0.18). The presence of the CGRP1 receptor on BMMC was confirmed by simultaneous immunofluorescent detection of RAMP1 or CRLR, the two components of the CGRP1 receptor, and mMCP‐1. Application of CGRP for 1 h evoked a concentration‐dependent release of mMCP‐1 (at EC50 10% of content) but not of β‐hexosaminidase and alterations in granular density indicative of piecemeal release. Conclusions & Inferences   We demonstrate that BMMC express functional CGRP1 receptors and that their activation causes mobilization of Ca2+ from intracellular stores and piecemeal release of mMCP‐1. These findings support the hypothesis that the CGRP signaling from afferent nerves to MMC in the gastrointestinal wall is receptor‐mediated.