Journal club-2021.07.23

Analysis of TRPV channel activation by stimulation of FCεRI and MRGPR receptors in mouse peritoneal mast cells

A. Sol ́ıs-Lo ́ pez1, U. Kriebs1, A. Marx1, S. Mannebach2, W. B. Liedtke3, M. J. Caterina4, M. Freichel1, V. V. Tsvilovskyy1*

1 PharmakologischesInstitut,Ruprecht-Karls-Universita ̈tHeidelberg,Heidelberg,Baden-Wu ̈rttemberg, Germany, 2 Experimentelle und Klinische Pharmakologie und Toxikologie, Universita ̈t des Saarlandes, Homburg, Saarland, Germany, 3 Department of Neurology, School of Medicine Duke University, Durham, North Carolina, United States of America, 4 Departments of Neurosurgery, Biological Chemistry, and Neuroscience, Neurosurgery Pain Research Institute, The Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America

Abstract

The activation of mast cells (MC) is part of the innate and adaptive immune responses and depends on Ca2+ entry across the plasma membrane, leading to the release of preformed inflammatory mediators by degranulation or by de novo synthesis. The calcium conducting channels of the TRPV family, known by their thermo and osmotic sensitivity, have been pro- posed to be involved in the MC activation in murine, rat, and human mast cell models. So far, immortalized mast cell lines and nonspecific TRPV blockers have been employed to charac- terize the role of TRPV channels in MC. The aim of this work was to elucidate the physiological role of TRPV channels by using primary peritoneal mast cells (PMCs), a model of connective tissue type mast cells. Our RT-PCR and NanoString analysis identified the expression of TRPV1, TRPV2, and TRPV4 channels in PMCs. For determination of the functional role of the expressed TRPV channels we performed measurements of intracellular free Ca2+ concentra- tions and beta-hexosaminidase release in PMCs obtained from wild type and mice deficient for corresponding TRPV1, TRPV2 and TRPV4 in response to various receptor-mediated and physical stimuli. Furthermore, substances known as activators of corresponding TRPV-chan- nels were also tested using these assays. Our results demonstrate that TRPV1, TRPV2, and TRPV4 do not participate in activation pathways triggered by activation of the high-affinity receptors for IgE (FcεRI), Mrgprb2 receptor, or Endothelin-1 receptor nor by heat or osmotic stimulation in mouse PMCs.