title: Physiological levels of 15-deoxy-Delta12,14-prostaglandin J2 prime eotaxin-induced chemotaxis on human eosinophils through peroxisome proliferator-activated receptor-gamma ligation.
abstract: 15-Deoxy-Delta12,14-PGJ2 (15d-PGJ2), mainly produced by mast cells, is known as a potent lipid mediator derived from PGD2 in vivo. 15d-PGJ2 was thought to exert its effects on cells exclusively through peroxisome proliferator-activated receptor-gamma (PPARgamma) and chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2), which are both expressed on human eosinophils. However, the physiological role of 15d-PGJ2 remains unclear, because the concentration generated in vivo is generally much lower than that required for its biological functions. In the present study we found that low concentrations (picomolar to low nanomolar) of 15d-PGJ2 and a synthetic PPARgamma agonist markedly enhanced the eosinophil chemotaxis toward eotaxin, and the effect was decreased in a dose-dependent manner. Moreover, at a low concentration (10(-10) M), 15d-PGJ2 and troglitazone primed eotaxin-induced shape change and actin polymerization. These priming effects were completely reversed by a specific PPARgamma antagonist, but were not mimicked by CRTH2 agonist 13,14-dihydro-15-keto-PGD2, suggesting that the effects were mediated through PPARgamma ligation. The effect exerted by 15d-PGJ2 parallels the enhancement of Ca2+ influx, but is not associated with the ERK, p38 MAPK, and NF-kappaB pathways. Furthermore, the time course and treatment of eosinophils with actinomycin D, an inhibitor of gene transcription, indicated that the transcription-independent pathway had a role in this process. PPARgamma might interact with an eotaxin-induced cytosolic signaling pathway, because PPARgamma is located in the eosinophil cytosol. Taken together with current findings, these results suggest that under physiological conditions, 15d-PGJ2 contributes to allergic inflammation through PPARgamma, which plays a role as a biphasic regulator of immune response.
authors.affiliation: Department of Clinical and Laboratory Medicine, Akita University School of Medicine, Akita, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Shigeharu
authors.initials: S
authors.lastname: Ueki
authors.forename: Gulixian
authors.initials: G
authors.lastname: Mahemuti
authors.forename: Takahito
authors.initials: T
authors.lastname: Chiba
authors.forename: Hajime
authors.initials: H
authors.lastname: Oyamada
authors.forename: Norihiro
authors.initials: N
authors.lastname: Saito
authors.forename: Akira
authors.initials: A
authors.lastname: Kanda
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kayaba
authors.forename: Junichi
authors.initials: J
authors.lastname: Chihara
mesh_terms: D002118:Calcium / Q000378:metabolism; D054413:Chemokine CCL11; D019742:Chemokines, CC / Q000494:pharmacology*; D002633:Chemotaxis / Q000187:drug effects*; D003599:Cytoskeleton / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004804:Eosinophils / Q000276:immunology*; D006801:Humans; D008024:Ligands; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology; D016328:NF-kappa B / Q000502:physiology; D047495:PPAR gamma / Q000502:physiology*; D015230:Prostaglandin D2 / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: C097240:15-deoxy-delta(12,14)-prostaglandin J2; C515456:CCL11 protein, human; D054413:Chemokine CCL11; D019742:Chemokines, CC; D008024:Ligands; D016328:NF-kappa B; D047495:PPAR gamma; D020928:Mitogen-Activated Protein Kinases; D015230:Prostaglandin D2; D002118:Calcium