101. Conserved IL-2Rγc Signaling Mediates Lymphopoiesis in Zebrafish.
- Author
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Sertori R, Liongue C, Basheer F, Lewis KL, Rasighaemi P, de Coninck D, Traver D, and Ward AC
- Subjects
- Animals, B-Lymphocytes immunology, Cell Line, Disease Models, Animal, Gene Knockdown Techniques, HEK293 Cells, Humans, Lymphopoiesis genetics, MAP Kinase Kinase 1 antagonists & inhibitors, Morpholinos genetics, Phosphoinositide-3 Kinase Inhibitors, Receptors, Interleukin-2 genetics, STAT5 Transcription Factor genetics, Severe Combined Immunodeficiency genetics, Signal Transduction immunology, T-Lymphocytes immunology, Zebrafish, Zebrafish Proteins genetics, Janus Kinase 3 genetics, Lymphopoiesis immunology, Receptors, Interleukin-2 immunology, Severe Combined Immunodeficiency immunology, Zebrafish Proteins immunology
- 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., (Copyright © 2015 by The American Association of Immunologists, Inc.)
- Published
- 2016
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