Stimulation of P2 purinergic receptors induces the release of eosinophil cationic protein and interleukin‐8 from human eosinophils

Abstract

1 Extracellular nucleotides are the focus of increasing attention for their role as extracellular mediators since they are released into the extracellular environment in a regulated manner and/or as a consequence of cell damage. 2 Here, we show that human eosinophils stimulated with different nucleotides release eosinophil cationic protein (ECP) and the chemokine interleukin 8 (IL-8), and that release of these two proteins has a different nucleotide requirement. 3 Release of ECP was triggered in a dose-dependent manner by ATP, UTP and UDP, but not by 2 0 -&3 0 -o-(4-benzoyl-benzoyl)adenosine 5 0 -triphosphate (BzATP), ADP and a,b-methylene adenosine 5 0 triphosphate (a,b-meATP). Release of IL-8 was triggered by UDP, ATP, a,b-meATP and BzATP, but not by UTP or ADP. Pretreatment with pertussis toxin abrogated nucleotide-stimulated ECP but not IL-8 release. 4 Release of IL-8 stimulated by BzATP was fully blocked by the P2X 7 blocker KN-62, while release triggered by ATP was only partially inhibited. IL-8 secretion due to UDP was fully insensitive to KN-62 inhibition. 5 Priming of eosinophils with GM-CSF increased IL-8 secretion irrespectively of the nucleotide used as a stimulant. 6 It is concluded that extracellular nucleotides trigger secretion of ECP by stimulating a receptor of the P2Y subfamily (possibly P2Y 2 ), while, on the contrary, nucleotide-stimulated secretion of IL-8 can be due to activation of both P2Y (P2Y 6 ) and P2X (P2X 1 and P2X 7 ) receptors.

Human neutrophil peptides induce interleukin-8 production through the P2Y6 signaling pathway

“…UDP alone has been shown to induce IL-8 release in the THP-1 monocytic cell line and human mature dendritic cells, 27,28 whereas ATP and UDP stimulate human eosinophils to produce IL-8. 26 In light of the direct stimulatory role of nucleotides to selectively induce IL-8 in different cell types 26,27 and the similar effects of HNPs and nucleotides, we demonstrated that the use of the P2 receptor antagonists suramin and reactive blue almost completely blocked HNP-induced IL-8 production. However, there appeared to be no direct interaction between HNP and P2 receptors because ATP and UDP did not compete with HNPs on cell-surface binding, or at least HNPs did not appear to share the same binding sites with ATP and UDP.…”

“…on March 28, 2019. by guest www.bloodjournal.org From pathways including P2Y 2 (ATP ϭ UTP) and P2Y 4 (UTP ϾϾ ATP) receptors, P2X ligand-gated ion channels, 26 and adenosine resulting from ATP degradation by nucleotidases through A 2b receptor 30,31 (Figure 1). Involvement of these pathways was investigated with the use of specific blockers.…”

“…At least 8 subtypes of P2Y receptors (P2Y 1 , P2Y 2 , P2Y 4 , P2Y 6 , P2Y 11 , P2Y 12 , P2Y 13 , and P2Y 14 ) expressed by mammalian cells have been identified, and each has different nucleotidebinding affinity. [22][23][24] 25,26 Recent studies have demonstrated UDP (ligand of P2Y 6 )-dependent IL-8 production from THP-1 monocytes, 27 human eosinophils, 26 and human mature dendritic cells. 28 In addition, products of ATP hydrolysis, such as adenosine monophosphate (AMP) 29,30 and adenosine 31 by cell-surface-associated nucleotidases, can also mediate IL-8 induction (Figure 1).…”

Identification and characterization of a novel variant of the human P2X7 receptor resulting in gain of function

“…MuLV Reverse Transcriptase (Applied Biosystems, Foster City, CA) was used to synthesize first-strand cDNA with oligo-dT [16][17][18] primer (Invitrogen, Carlsbad, CA) from 1 µg of the purified total RNA at 42°C for 60 min. A pair of the sequence-specific primers with Xho I sites were designed based on the published human P2X 7 cDNA sequence to amplify the entire coding sequence of the human P2X 7 subunit by PCR [53].…”

“…P2X 7 receptors are predominantly expressed on cells from the hematopoietic lineages, such as erythrocytes, lymphocytes, neutrophils, eosinophils, mast cells, monocytes, and macrophages [9][10][11][12][13][14][15][16][17][18]. It has been reported recently that P2X 7 receptors are expressed in central and spinal cord neurons [19][20][21][22].…”