Department of Pharmacology, Jikei University School of Medicine, Tokyo, Japan;
Atopy (Allergy) Research Center, Juntendo University Graduate School of Medicine, Tokyo, Japan.
J Immunol. 2021 Aug 15;207(4):1001-1008. doi: 10.4049/jimmunol.2001002. Epub 2021 Jul 30.
Mast cells express multiple metabotropic purinergic P2Y receptor (P2YR) subtypes. Few studies have evaluated their role in human mast cell (HMC) allergic response as quantified by degranulation induced by cross-linking the high-affinity IgE receptor (FcεRI). We have previously shown that extracellular nucleotides modify the FcεRI activation-dependent degranulation in HMCs derived from human lungs, but the mechanism of this action has not been fully delineated. This study was undertaken to determine the mechanism of activation of P2YRs on the degranulation of HMCs and elucidate the specific postreceptor pathways involved. Sensitized LAD2 cells, a human-derived mast cell line, were subjected to a weak allergic stimulation (WAS) using a low concentration of Ag in the absence and presence of P2YR agonists. Only the metabotropic purinergic P2Y11 receptor (P2Y11R) agonist, adenosine 5'-(3-thio)triphosphate (ATPγS), enhanced WAS-induced degranulation resulting in a net 7-fold increase in release ( = 4; < 0.01). None of the P2YR agonists tested, including high concentrations of ATPγS (1000 μM), enhanced WAS-induced intracellular Ca mobilization, an essential component of activated FcεRI-induced degranulation. Both a PI3K inhibitor and the relevant gene knockout decreased the ATPγS-induced enhancement. The effect of ATPγS was associated with enhanced phosphorylation of PI3K type δ and protein kinase B, but not the phosphoinositide-dependent kinase-1. The effects of ATPγS were dose dependently inhibited by NF157, a P2Y11R antagonist. To our knowledge, these data indicate for the first time that P2YR is linked to enhancement of allergic degranulation in HMC via the PI3K/protein kinase B pathway.
肥大细胞表达多种代谢型嘌呤能 P2Y 受体 (P2YR) 亚型。很少有研究评估它们在人类肥大细胞 (HMC) 过敏反应中的作用，该反应通过交联高亲和力 IgE 受体 (FcεRI) 诱导脱颗粒来定量。我们之前已经表明，细胞外核苷酸可以修饰源自人肺的 HMC 中 FcεRI 激活依赖性脱颗粒，但其作用机制尚未完全阐明。本研究旨在确定 P2YR 在 HMC 脱颗粒中的激活机制，并阐明涉及的特定受体后途径。致敏的 LAD2 细胞是一种源自人类的肥大细胞系，在不存在和存在 P2YR 激动剂的情况下，用低浓度 Ag 进行弱过敏刺激 (WAS)。只有代谢型嘌呤能 P2Y11 受体 (P2Y11R) 激动剂，腺苷 5'-(3-硫)三磷酸 (ATPγS)，增强了 WAS 诱导的脱颗粒，导致释放的净增加 7 倍 ( = 4； < 0.01)。测试的所有 P2YR 激动剂，包括高浓度的 ATPγS(1000 μM)，均未增强 WAS 诱导的细胞内 Ca 动员，这是激活的 FcεRI 诱导脱颗粒的重要组成部分。PI3K 抑制剂和相关基因敲除均降低了 ATPγS 诱导的增强作用。ATPγS 的作用与 PI3K 型 δ 和蛋白激酶 B 的磷酸化增强有关，但与磷酸肌醇依赖性激酶-1 无关。NF157，一种 P2Y11R 拮抗剂，剂量依赖性地抑制了 ATPγS 的作用。据我们所知，这些数据首次表明，P2YR 通过 PI3K/蛋白激酶 B 途径与 HMC 过敏脱颗粒的增强有关。
