TY - JOUR
T1 - Negative regulation of γ-globin gene expression by cyclic AMP-dependent pathway in erythroid cells
AU - Inoue, Akio
AU - Kuroyanagi, Yuichi
AU - Terui, Kiminori
AU - Moi, Paolo
AU - Ikuta, Tohru
N1 - Funding Information:
This study was supported by National Institutes of Health Grants DK61806 and HL73452 to Dr. Ikuta and Innovation of Clinical Research Award Grant 20010423 from the Doris Duke Charitable Foundation to Dr. Ikuta. The authors thank Dr. M. Montminy for a CREB antibody.
PY - 2004/3
Y1 - 2004/3
N2 - Objective. Fetal hemoglobin inducers such as hemin, butyrate, and hydroxyurea stimulate γ-globin gene expression by activating the cyclic GMP (cGMP)-dependent pathway. Although cGMP activates the cyclic AMP (cAMP)-dependent pathway by suppressing cGMP-inhibited phosphodiesterase 3 (PDE3), the effects of the cAMP-dependent pathway on γ-globin gene expression are unknown. Materials and Methods. The cAMP-dependent pathway was activated in K562 cells using the adenylate cyclase activator forskolin. Expression of γ-globin mRNA was examined by primer extension, and transcriptional activity of the γ-globin gene promoter was determined by reporter gene assays. Results. PDE3 was expressed in K562 cells at a high level. The cAMP-dependent pathway was found to be activated in K562 cells in which the cGMP-dependent pathway was activated by hemin. Activation of the cAMP-dependent pathway by forskolin inhibited hemin-induced expression of γ-globin mRNA and decreased transcriptional activity of the γ-globin gene promoter. The levels of phosphorylation of mitogen-activated protein kinases (MAPKs) were not affected by the cAMP-dependent pathway. Conclusions. These results suggested that the cAMP-dependent pathway, which is independent of MAPK pathways, plays a negative role in γ-globin gene expression in K562 cells. cAMP and cGMP may have differential roles in the regulation of γ-globin gene expression in erythroid cells.
AB - Objective. Fetal hemoglobin inducers such as hemin, butyrate, and hydroxyurea stimulate γ-globin gene expression by activating the cyclic GMP (cGMP)-dependent pathway. Although cGMP activates the cyclic AMP (cAMP)-dependent pathway by suppressing cGMP-inhibited phosphodiesterase 3 (PDE3), the effects of the cAMP-dependent pathway on γ-globin gene expression are unknown. Materials and Methods. The cAMP-dependent pathway was activated in K562 cells using the adenylate cyclase activator forskolin. Expression of γ-globin mRNA was examined by primer extension, and transcriptional activity of the γ-globin gene promoter was determined by reporter gene assays. Results. PDE3 was expressed in K562 cells at a high level. The cAMP-dependent pathway was found to be activated in K562 cells in which the cGMP-dependent pathway was activated by hemin. Activation of the cAMP-dependent pathway by forskolin inhibited hemin-induced expression of γ-globin mRNA and decreased transcriptional activity of the γ-globin gene promoter. The levels of phosphorylation of mitogen-activated protein kinases (MAPKs) were not affected by the cAMP-dependent pathway. Conclusions. These results suggested that the cAMP-dependent pathway, which is independent of MAPK pathways, plays a negative role in γ-globin gene expression in K562 cells. cAMP and cGMP may have differential roles in the regulation of γ-globin gene expression in erythroid cells.
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U2 - 10.1016/j.exphem.2003.12.006
DO - 10.1016/j.exphem.2003.12.006
M3 - Article
C2 - 15003309
AN - SCOPUS:1542267418
SN - 0301-472X
VL - 32
SP - 244
EP - 253
JO - Experimental Hematology
JF - Experimental Hematology
IS - 3
ER -
