Signal transducers and activators of transcription 3 augments the transcriptional activity of CCAAT/enhancer-binding protein alpha in granulocyte colony-stimulating factor signaling pathway.
The Janus kinase (Jak)-Stat pathway plays an essential role in cytokine signaling. Granulocyte colony-stimulating factor (G-CSF) promotes granulopoiesis and granulocytic differentiation, and Stat3 is the principle Stat protein activated by G-CSF. Upon treatment with G-CSF, the interleukin-3-dependent cell line 32D clone 3(32Dcl3) differentiates into neutrophils, and 32Dcl3 cells expressing dominant-negative Stat3 (32Dcl3/DNStat3) proliferate in G-CSF without differentiation. Gene expression profile and quantitative PCR analysis of G-CSF-stimulated cell lines revealed that the expression of C/EBPalpha was up-regulated by the activation of Stat3. In addition, activated Stat3 bound to CCAAT/enhancer-binding protein (C/EBP)alpha, leading to the enhancement of the transcription activity of C/EBPalpha. Conditional expression of C/EBPalpha in 32Dcl3/DNStat3 cells after G-CSF stimulation abolishes the G-CSF-dependent cell proliferation and induces granulocytic differentiation. Although granulocyte-specific genes, such as the G-CSF receptor, lysozyme M, and neutrophil gelatinase-associated lipocalin precursor (NGAL) are regulated by Stat3, only NGAL was induced by the restoration of C/EBPalpha after stimulation with G-CSF in 32Dcl3/DNStat3 cells. These results show that one of the major roles of Stat3 in the G-CSF signaling pathway is to augment the function of C/EBPalpha, which is essential for myeloid differentiation. Additionally, cooperation of C/EBPalpha with other Stat3-activated proteins are required for the induction of some G-CSF responsive genes including lysozyme M and the G-CSF receptor.
Numata
Akihiko
A
Medicine and Biosystemic Science, Kyushu University Graduate School of Medical Sciences, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka, 812-8582, Japan.
Shimoda
Kazuya
K
Kamezaki
Kenjiro
K
Haro
Takashi
T
Kakumitsu
Haruko
H
Shide
Koutarou
K
Kato
Kouji
K
Miyamoto
Toshihiro
T
Yamashita
Yoshihiro
Y
Oshima
Yasuo
Y
Nakajima
Hideaki
H
Iwama
Atsushi
A
Aoki
Kenichi
K
Takase
Ken
K
Gondo
Hisashi
H
Mano
Hiroyuki
H
Harada
Mine
M
D000209:Acute-Phase Proteins / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000378:metabolism*; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D016207:Cytokines / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism* / Q000502:physiology*; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D005799:Genes, Dominant; D016179:Granulocyte Colony-Stimulating Factor / Q000378:metabolism*; D006098:Granulocytes / Q000166:cytology / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D016898:Interferon-alpha / Q000378:metabolism; D007377:Interleukin-3 / Q000378:metabolism; D000071068:Lipocalin-2; D054834:Lipocalins; D051379:Mice; D009113:Muramidase / Q000737:chemistry / Q000378:metabolism; D022423:Myeloid Cells / Q000378:metabolism*; D009504:Neutrophils / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D015513:Oncogene Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050796:STAT3 Transcription Factor; D015398:Signal Transduction; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism* / Q000502:physiology*; D014158:Transcription, Genetic
D000209:Acute-Phase Proteins; D022763:CCAAT-Enhancer-Binding Protein-alpha; D016207:Cytokines; D004268:DNA-Binding Proteins; D016898:Interferon-alpha; D007377:Interleukin-3; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; D015513:Oncogene Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; C494087:Stat3 protein, mouse; D015534:Trans-Activators; D016179:Granulocyte Colony-Stimulating Factor; D009113:Muramidase