Allergology International

Allergology International

Volume 66, Issue 4, October 2017, Pages 574-580
Allergology International

Original article
UDP/P2Y6 receptor signaling regulates IgE-dependent degranulation in human basophils

https://doi.org/10.1016/j.alit.2017.02.014Get rights and content
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Abstract

Background

P2Y purinergic receptors (P2YR) are G protein-coupled receptors that are stimulated by extracellular nucleotides. They mediate cellular effects by regulating cAMP production, protein kinase C activation, inositol trisphosphate generation, and Ca2+ release from intracellular stores. The P2Y6 receptor of this family is selectively stimulated by UDP, and selectively inhibited by MRS2578. In the present study, we examined the effect of UDP/P2Y6 receptor signaling on IgE-dependent degranulation in human basophils.

Methods

Basophils were purified from human peripheral blood. The mRNA expression of genes encoding P2YR and ecto-nucleoside triphosphate diphosphohydrolase (ENTPDase) was measured by RT-PCR. Intracellular Ca2+ influx via UDP/P2Y6 receptor signaling in basophils was detected using a calcium probe. The effect of UDP/P2Y6 receptor signaling on IgE-dependent degranulation in basophils was confirmed by measuring CD63 expression by flow cytometry. Autocrine secretion of nucleotides was detected by HPLC analysis.

Results

We showed that purified basophils express P2Y6 mRNA and that UDP increased intracellular Ca2+, which was reduced by MRS2578 treatment. UDP promoted IgE-dependent degranulation. Furthermore, MRS2578 inhibited IgE-dependent degranulation in basophils. HPLC analysis indicated that basophils spontaneously secrete UTP. In addition, basophils expressed the extracellular nucleotide hydrolases ENTPDase2, ENTPDase3, and ENTPDase8.

Conclusions

This study showed that UDP/P2Y6 receptor signaling is involved in the regulation of IgE-dependent degranulation in basophils, which might stimulate the P2Y6 receptor via the autocrine secretion of UTP. Thus, this receptor represents a potential target to regulate IgE-dependent degranulation in basophils during allergic diseases.

Keywords

Basophil
IgE-dependent degranulation
MRS2578
P2Y6
UDP

Abbreviations

P2YR
P2Y purinergic receptors
GPCR
G-protein coupled receptor
ENTPDase
ecto-nucleoside triphosphate diphosphohydrolase
AC
adenylate cyclase
PLC
phospholipase C
PKC
protein kinase C
MFI
mean fluorescence intensity
7-AAD
7-amino-actinomycin D
ENPP
ecto-nucleotide pyrophosphatase/phosphodiesterase

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Peer review under responsibility of Japanese Society of Allergology.