title: Expression of DP2 (CRTh2), a prostaglandin D₂ receptor, in human mast cells.
abstract: PGD₂ has long been implicated in allergic diseases. Recent cloning of a second PGD₂ receptor, DP2 (also known as CRTh2), led to a greater understanding of the physiological and pathophysiological implications of PGD₂. PGD₂ signaling through DP1 and DP2 mediates different and often opposite effects in many cell types of the immune system. Although mast cells (MC) are the largest source of PGD₂ in the body, there is little information about their potential expression of DP2 and its functional significance. In this study, we show that tissue MC in human nasal polyps express DP2 protein, and that human MC lines and primary cultured human MC express mRNA as well as protein of DP2. By immunohistochemistry, we detected that 34% of MC in human nasal polyps expressed DP2. In addition, flow cytometry showed that 87% of the LAD2 human MC line and 98% of primary cultured human MC contained intracellular DP2. However, we could not detect surface expression of DP2 on human MC by single cell analysis using imaging flow cytometry. Blocking of endogenous PGD2 production with aspirin did not induce surface expression of DP2 in human MC. Two DP2 selective agonists, DK-PGD₂ and 15R-15-methyl PGD₂ induced dose-dependent intracellular calcium mobilization that was abrogated by pertussis toxin, but not by three DP2 selective antagonists. MC mediator release including degranulation was not affected by DP2 selective agonists. Thus, human MC express DP2 intracellularly rather than on their surface, and the function of DP2 in human MC is different than in other immune cells such as Th2 cells, eosinophils and basophils where it is expressed on the cell surface and induces Th2 cytokine and/or granule associated mediator release. Further studies to elucidate the role of intracellular DP2 in human MC may expand our understanding of this molecule and provide novel therapeutic opportunities.
authors.affiliation: Pulmonary Research Group, Department of Medicine, University of Alberta, Edmonton, AB, Canada.
authors.forename: Tae Chul
authors.initials: TC
authors.lastname: Moon
authors.affiliation: Pulmonary Research Group, Department of Medicine, University of Alberta, Edmonton, AB, Canada.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Campos-Alberto
authors.affiliation: Pulmonary Research Group, Department of Medicine, University of Alberta, Edmonton, AB, Canada.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Yoshimura
authors.affiliation: Pulmonary Research Group, Department of Medicine, University of Alberta, Edmonton, AB, Canada.
authors.forename: Graeme
authors.initials: G
authors.lastname: Bredo
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
authors.forename: Aja M
authors.initials: AM
authors.lastname: Rieger
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Alberta Hospitals, Edmonton, AB, Canada.
authors.forename: Lakshmi
authors.initials: L
authors.lastname: Puttagunta
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada; Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Barreda
authors.affiliation: Pulmonary Research Group, Department of Medicine, University of Alberta, Edmonton, AB, Canada.
authors.forename: A Dean
authors.initials: AD
authors.lastname: Befus
authors.affiliation: Pulmonary Research Group, Department of Medicine, University of Alberta, Edmonton, AB, Canada; Department of Pathology and Laboratory Medicine, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada.
authors.forename: Lisa
authors.initials: L
authors.lastname: Cameron
mesh_terms: D001241:Aspirin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D015550:Cell Degranulation / Q000187:drug effects; D002460:Cell Line; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D017136:Ion Transport; D020014:K562 Cells; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008407:Mast Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009298:Nasal Polyps / Q000378:metabolism; D037342:Pertussis Toxin / Q000494:pharmacology; D061251:Primary Cell Culture; D015230:Prostaglandin D2 / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000494:pharmacology; D012333:RNA, Messenger / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D011971:Receptors, Immunologic / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D011982:Receptors, Prostaglandin / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism
chemical_list: C532725:15R-methyl prostaglandin D2; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D011982:Receptors, Prostaglandin; D037342:Pertussis Toxin; D001241:Aspirin; D015230:Prostaglandin D2; D002118:Calcium; C036293:prostaglandin D2 receptor