title: Abrogation of prostaglandin E2/EP4 signaling impairs the development of rag1+ lymphoid precursors in the thymus of zebrafish embryos.
abstract: PGE(2) is involved in a wide variety of physiological and pathological processes; however, deciphering its role in early mammalian development has been difficult due to the maternal contribution of PGE(2). To overcome this limitation we have investigated the role of PGE(2) during T cell development in zebrafish. In this study, we show that zebrafish ep4a, a PGE(2) receptor isoform of EP4, is expressed at 26 h postfertilization in the dorsal aorta-posterior cardinal vein joint region, which has a high homology with the mammal aorta-gonad-mesonephros area and where definitive hemopoiesis arises. Furthermore, it is expressed in the presumptive thymus rudiment by 48 h postfertilization. Supplementation of PGE(2) results in a strong increase in rag1 levels and cell proliferation in the thymus. In contrast, the inhibition of PGE(2) production, as well as EP4 blockade, abrogates the expression of rag1 in the thymus and that of the lymphoid precursor marker ikaros, not only in the dorsal aorta-posterior cardinal vein joint region but also in the newly identified caudal hemopoietic tissue without affecting early hemopoietic (scl, gata2) and erythropoietic (gata1) markers. These results identify ep4a as the earliest thymus marker and define a novel role for the PGE(2)/EP4 pathway in controlling T cell precursor development in zebrafish.
authors.affiliation: Cancer Gene Therapy Unit, Cancer Immunotherapy and Gene Therapy Program, Scientific Institute H. San Raffaele, Via Olgettina 58, Milan, Italy.
authors.forename: Eduardo J
authors.initials: EJ
authors.lastname: Villablanca
authors.forename: Anna
authors.initials: A
authors.lastname: Pistocchi
authors.forename: Felipe A
authors.initials: FA
authors.lastname: Court
authors.forename: Franco
authors.initials: F
authors.lastname: Cotelli
authors.forename: Claudio
authors.initials: C
authors.lastname: Bordignon
authors.forename: Miguel L
authors.initials: ML
authors.lastname: Allende
authors.forename: Catia
authors.initials: C
authors.lastname: Traversari
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Russo
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D002454:Cell Differentiation / Q000276:immunology*; D049109:Cell Proliferation; D015232:Dinoprostone / Q000037:antagonists & inhibitors / Q000502:physiology; D006410:Hematopoiesis / Q000276:immunology; D018398:Homeodomain Proteins / Q000096:biosynthesis*; D016131:Lymphocyte Subsets / Q000166:cytology / Q000378:metabolism*; D038041:Lymphopoiesis / Q000276:immunology; D020033:Protein Isoforms / Q000037:antagonists & inhibitors / Q000502:physiology; D018078:Receptors, Prostaglandin E / Q000037:antagonists & inhibitors / Q000502:physiology*; D058309:Receptors, Prostaglandin E, EP4 Subtype; D015398:Signal Transduction / Q000276:immunology*; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D013950:Thymus Gland / Q000166:cytology / Q000196:embryology / Q000276:immunology*; D015854:Up-Regulation / Q000276:immunology; D015027:Zebrafish / Q000196:embryology* / Q000276:immunology
chemical_list: D018398:Homeodomain Proteins; D020033:Protein Isoforms; D018078:Receptors, Prostaglandin E; D058309:Receptors, Prostaglandin E, EP4 Subtype; C064658:RAG-1 protein; D015232:Dinoprostone