title: Conserved IL-2Rγc Signaling Mediates Lymphopoiesis in Zebrafish.
abstract: The IL-2 receptor γ common (IL-2Rγc) chain is the shared subunit of the receptors for the IL-2 family of cytokines, which mediate signaling through JAK3 and various downstream pathways to regulate lymphopoiesis. Inactivating mutations in human IL-2Rγc result in SCID, a primary immunodeficiency characterized by greatly reduced numbers of lymphocytes. This study used bioinformatics, expression analysis, gene ablation, and specific pharmacologic inhibitors to investigate the function of two putative zebrafish IL-2Rγc paralogs, il-2rγc.a and il-2rγc.b, and downstream signaling components during early lymphopoiesis. Expression of il-2rγc.a commenced at 16 h post fertilization (hpf) and rose steadily from 4-6 d postfertilization (dpf) in the developing thymus, with il-2rγc.a expression also confirmed in adult T and B lymphocytes. Transcripts of il-2rγc.b were first observed from 8 hpf, but waned from 16 hpf before reaching maximal expression at 6 dpf, but this was not evident in the thymus. Knockdown of il-2rγc.a, but not il-2rγc.b, substantially reduced embryonic lymphopoiesis without affecting other aspects of hematopoiesis. Specific targeting of zebrafish Jak3 exerted a similar effect on lymphopoiesis, whereas ablation of zebrafish Stat5.1 and pharmacologic inhibition of PI3K and MEK also produced significant but smaller effects. Ablation of il-2rγc.a was further demonstrated to lead to an absence of mature T cells, but not B cells in juvenile fish. These results indicate that conserved IL-2Rγc signaling via JAK3 plays a key role during early zebrafish lymphopoiesis, which can be potentially targeted to generate a zebrafish model of human SCID.
authors.affiliation: School of Medicine, Deakin University, Geelong, Victoria 3216, Australia; Centre for Molecular and Medical Research, Deakin University, Geelong, Victoria 3216, Australia;
authors.forename: Robert
authors.initials: R
authors.lastname: Sertori
authors.affiliation: School of Medicine, Deakin University, Geelong, Victoria 3216, Australia; Centre for Molecular and Medical Research, Deakin University, Geelong, Victoria 3216, Australia;
authors.forename: Clifford
authors.identifier: http://orcid.org/0000-0002-1646-4905
authors.initials: C
authors.lastname: Liongue
authors.affiliation: School of Medicine, Deakin University, Geelong, Victoria 3216, Australia; Centre for Molecular and Medical Research, Deakin University, Geelong, Victoria 3216, Australia;
authors.forename: Faiza
authors.initials: F
authors.lastname: Basheer
authors.affiliation: Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093; and.
authors.forename: Kanako L
authors.initials: KL
authors.lastname: Lewis
authors.affiliation: School of Medicine, Deakin University, Geelong, Victoria 3216, Australia; Centre for Molecular and Medical Research, Deakin University, Geelong, Victoria 3216, Australia;
authors.forename: Parisa
authors.initials: P
authors.lastname: Rasighaemi
authors.affiliation: School of Medicine, Deakin University, Geelong, Victoria 3216, Australia; GROW School for Oncology and Developmental Biology, Maastricht University, Maastricht 6200, the Netherlands.
authors.forename: Dennis
authors.identifier: http://orcid.org/0000-0002-0575-1554
authors.initials: D
authors.lastname: de Coninck
authors.affiliation: Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093; and.
authors.forename: David
authors.initials: D
authors.lastname: Traver
authors.affiliation: School of Medicine, Deakin University, Geelong, Victoria 3216, Australia; Centre for Molecular and Medical Research, Deakin University, Geelong, Victoria 3216, Australia; award@deakin.edu.au.
authors.forename: Alister C
authors.initials: AC
authors.lastname: Ward
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D002460:Cell Line; D004195:Disease Models, Animal; D055785:Gene Knockdown Techniques; D057809:HEK293 Cells; D006801:Humans; D053616:Janus Kinase 3 / Q000235:genetics*; D038041:Lymphopoiesis / Q000235:genetics / Q000276:immunology*; D048369:MAP Kinase Kinase 1 / Q000037:antagonists & inhibitors; D060172:Morpholinos / Q000235:genetics; D000081082:Phosphoinositide-3 Kinase Inhibitors; D015375:Receptors, Interleukin-2 / Q000235:genetics / Q000276:immunology*; D050799:STAT5 Transcription Factor / Q000235:genetics; D016511:Severe Combined Immunodeficiency / Q000235:genetics / Q000276:immunology*; D015398:Signal Transduction / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000235:genetics / Q000276:immunology*
chemical_list: D060172:Morpholinos; D000081082:Phosphoinositide-3 Kinase Inhibitors; D015375:Receptors, Interleukin-2; D050799:STAT5 Transcription Factor; D029961:Zebrafish Proteins; C494098:ihb394 protein, zebrafish; D053616:Janus Kinase 3; D048369:MAP Kinase Kinase 1