PMID- 31849935 OWN - NLM STAT- MEDLINE DCOM- 20201110 LR - 20201110 IS - 1664-3224 (Electronic) IS - 1664-3224 (Linking) VI - 10 DP - 2019 TI - Pannexin-1 Channels Are Essential for Mast Cell Degranulation Triggered During Type I Hypersensitivity Reactions. PG - 2703 LID - 10.3389/fimmu.2019.02703 [doi] LID - 2703 AB - Mast cells (MCs) release pro-inflammatory mediators through a process called degranulation response. The latter may be induced by several conditions, including antigen recognition through immunoglobulin E (IgE) or "cross-linking," classically associated with Type I hypersensitivity reactions. Early in this reaction, Ca(2+) influx and subsequent increase of intracellular free Ca(2+) concentration are essential for MC degranulation. Several membrane channels that mediate Ca(2+) influx have been proposed, but their role remains elusive. Here, we evaluated the possible contribution of pannexin-1 channels (Panx1 Chs), well-known as ATP-releasing channels, in the increase of intracellular Ca(2+) triggered during cross-linking reaction of MCs. The contribution of Panx1 Chs in the degranulation response was evaluated in MCs from wild type (WT) and Panx1 knock out (Panx1(-/-)) mice after anti-ovalbumin (OVA) IgE sensitization. Notably, the degranulation response (toluidine blue and histamine release) was absent in Panx1(-/-) MCs. Moreover, WT MCs showed a rapid and transient increase in Ca(2+) signal followed by a sustained increase after antigen stimulation. However, the sustained increase in Ca(2+) signal triggered by OVA was absent in Panx1(-/-) MCs. Furthermore, OVA stimulation increased the membrane permeability assessed by dye uptake, a prevented response by Panx1 Ch but not by connexin hemichannel blockers and without effect on Panx1(-/-) MCs. Interestingly, the increase in membrane permeability of WT MCs was also prevented by suramin, a P2 purinergic inhibitor, suggesting that Panx1 Chs act as ATP-releasing channels impermeable to Ca(2+). Accordingly, stimulation with exogenous ATP restored the degranulation response and sustained increase in Ca(2+) signal of OVA stimulated Panx1(-/-) MCs. Moreover, opening of Panx1 Chs in Panx1 transfected HeLa cells increased dye uptake and ATP release but did not promote Ca(2+) influx, confirming that Panx1 Chs permeable to ATP are not permeable to Ca(2+). These data strongly suggest that during antigen recognition, Panx1 Chs contribute to the sustained Ca(2+) signal increase via release of ATP that activates P2 receptors, playing a critical role in the sequential events that leads to degranulation response during Type I hypersensitivity reactions. CI - Copyright (c) 2019 Harcha, Lopez, Saez, Fernandez, Barria, Martinez and Saez. FAU - Harcha, Paloma A AU - Harcha PA AD - Departamento de Fisiologia, Facultad de Ciencias Biologicas, Pontificia Universidad Catolica de Chile, Santiago, Chile. AD - Facultad de Ciencias, Instituto de Neurociencias and Centro Interdisciplinario de Neurociencias de Valparaiso, Universidad de Valparaiso, Valparaiso, Chile. FAU - Lopez, Ximena AU - Lopez X AD - Departamento de Fisiologia, Facultad de Ciencias Biologicas, Pontificia Universidad Catolica de Chile, Santiago, Chile. AD - Facultad de Ciencias, Instituto de Neurociencias and Centro Interdisciplinario de Neurociencias de Valparaiso, Universidad de Valparaiso, Valparaiso, Chile. FAU - Saez, Pablo J AU - Saez PJ AD - Departamento de Fisiologia, Facultad de Ciencias Biologicas, Pontificia Universidad Catolica de Chile, Santiago, Chile. AD - Institut Curie, PSL Research University, CNRS, UMR 144, Paris, France. AD - Institut Pierre-Gilles de Gennes, PSL Research University, Paris, France. FAU - Fernandez, Paola AU - Fernandez P AD - Facultad de Ciencias, Instituto de Neurociencias and Centro Interdisciplinario de Neurociencias de Valparaiso, Universidad de Valparaiso, Valparaiso, Chile. FAU - Barria, Ivan AU - Barria I AD - Facultad de Ciencias, Instituto de Neurociencias and Centro Interdisciplinario de Neurociencias de Valparaiso, Universidad de Valparaiso, Valparaiso, Chile. FAU - Martinez, Agustin D AU - Martinez AD AD - Facultad de Ciencias, Instituto de Neurociencias and Centro Interdisciplinario de Neurociencias de Valparaiso, Universidad de Valparaiso, Valparaiso, Chile. FAU - Saez, Juan C AU - Saez JC AD - Departamento de Fisiologia, Facultad de Ciencias Biologicas, Pontificia Universidad Catolica de Chile, Santiago, Chile. AD - Facultad de Ciencias, Instituto de Neurociencias and Centro Interdisciplinario de Neurociencias de Valparaiso, Universidad de Valparaiso, Valparaiso, Chile. LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20191129 PL - Switzerland TA - Front Immunol JT - Frontiers in immunology JID - 101560960 RN - 0 (Connexins) RN - 0 (Nerve Tissue Proteins) RN - 0 (PANX1 protein, human) RN - 0 (Panx1 protein, mouse) SB - IM MH - Animals MH - Cell Degranulation/*physiology MH - Connexins/*immunology/metabolism MH - HeLa Cells MH - Humans MH - Hypersensitivity, Immediate/*immunology/metabolism MH - Mast Cells/*immunology/metabolism MH - Mice MH - Mice, Inbred C57BL MH - Mice, Knockout MH - Nerve Tissue Proteins/*immunology/metabolism PMC - PMC6896164 OTO - NOTNLM OT - ATP OT - degranulation OT - histamine OT - immune cells OT - inflammation OT - ovalbumin OT - pannexon EDAT- 2019/12/19 06:00 MHDA- 2020/11/11 06:00 PMCR- 2019/01/01 CRDT- 2019/12/19 06:00 PHST- 2019/07/18 00:00 [received] PHST- 2019/11/04 00:00 [accepted] PHST- 2019/12/19 06:00 [entrez] PHST- 2019/12/19 06:00 [pubmed] PHST- 2020/11/11 06:00 [medline] PHST- 2019/01/01 00:00 [pmc-release] AID - 10.3389/fimmu.2019.02703 [doi] PST - epublish SO - Front Immunol. 2019 Nov 29;10:2703. doi: 10.3389/fimmu.2019.02703. eCollection 2019.