Requirement of gp130 signaling for the AGM hematopoiesis.
OBJECTIVE
Definitive hematopoiesis starts in the aorta-gonad-mesonephros (AGM) region during mouse development and remarkably expands in the liver at a later stage of ontogeny. gp130 is a signal transducing receptor component shared by all the IL-6 family cytokines, whose gene ablation in mouse results in the significant reduction in the fetal liver hematopoiesis. The present study aims to evaluate the role of gp130 signaling in the fetal mouse AGM hematopoiesis.


METHODS
Mouse AGM regions from the wild-type and gp130-deficient mice on embryonic day 11.5 were dissociated and cultured with a mixture of cytokines, including one which activates gp130. Wild-type human gp130 and its mutant constructs were introduced into cultured gp130-deficient AGM cells using retrovirus system. To further analyze gp130 downstream signaling, a dominant-negative mutant of STAT3 was also introduced.


RESULTS
The gp130 deficiency in the culture of fetal mouse AGM cells resulted in the failure of the expansion of the c-kit(+), Sca-1(+), and lineage markers(-) population. Such failure was rescued by introduction of a wild-type gp130 expression construct but not its mutant constructs having no ability to activate STAT3. In the normal AGM cell culture, introduction of a dominant-negative form of STAT3 in which Y(705) was changed to phenylalanine suppressed the expansion of hematopoietic cell colonies.


CONCLUSIONS
gp130 plays an indispensable role in the expansion of hematopoietic precursor cells in the fetal mouse AGM. In particular, the activation of STAT3 by gp130 is found to be important in this process.
Takizawa
Makiko
M
Department of Cell Fate Modulation, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto, Japan.
Nobuhisa
Ikuo
I
Igarashi
Katsuhide
K
Ueno
Masaya
M
Nakashima
Kinichi
K
Kitamura
Toshio
T
Taga
Tetsuya
T
D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000502:physiology*; D001011:Aorta / Q000166:cytology / Q000196:embryology*; D002452:Cell Count; D002455:Cell Division; D002478:Cells, Cultured; D050822:Cytokine Receptor gp130; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D015870:Gene Expression; D005786:Gene Expression Regulation; D019940:Genes, bcl-1 / Q000235:genetics; D020570:Genes, myb / Q000235:genetics; D006066:Gonads / Q000166:cytology / Q000196:embryology*; D049452:Green Fluorescent Proteins; D006410:Hematopoiesis; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D017493:Leukocyte Common Antigens / Q000032:analysis; D008164:Luminescent Proteins / Q000235:genetics; D008562:Membrane Glycoproteins / Q000235:genetics / Q000502:physiology*; D008650:Mesonephros / Q000166:cytology / Q000196:embryology*; D051379:Mice; D008813:Mice, Inbred ICR; D009154:Mutation; D053683:Oncostatin M; D010455:Peptides / Q000494:pharmacology; D010766:Phosphorylation; D050796:STAT3 Transcription Factor; D015398:Signal Transduction; D019089:Stem Cell Factor / Q000494:pharmacology; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014162:Transfection
D015703:Antigens, CD; D004268:DNA-Binding Proteins; C494200:Il6st protein, mouse; D008164:Luminescent Proteins; D008562:Membrane Glycoproteins; C508351:OSM protein, human; C508352:Osm protein, mouse; D010455:Peptides; D050796:STAT3 Transcription Factor; C494087:Stat3 protein, mouse; D019089:Stem Cell Factor; D015534:Trans-Activators; D016222:Fibroblast Growth Factor 2; D053683:Oncostatin M; D050822:Cytokine Receptor gp130; D049452:Green Fluorescent Proteins; D017493:Leukocyte Common Antigens