TY - JOUR
T1 - Glucocorticoid stimulation of corticotropin-releasing hormone gene expression requires a cyclic adenosine 3′,5′-monophosphate regulatory element in human primary placental cytotrophoblast cells
AU - Cheng, You Hong
AU - Nicholson, Richard C.
AU - King, Bruce
AU - Chan, Eng Cheng
AU - Fitter, John T.
AU - Smith, Roger
PY - 2000
Y1 - 2000
N2 - Production of placental CRH, which is identical to the peptide synthesized and secreted in the hypothalamus, has been linked to human parturition. Glucocorticoids stimulate placental CRH secretion and messenger ribonucleic acid expression, in contrast to their inhibition of CRH synthesis in the hypothalamus. A positive feedforward loop involving glucocorticoid-CRH-ACTH-glucocorticoid is thought to drive the exponential increase in placental CRH leading to delivery. Tissue-specific effects of glucocorticoids on CRH expression are therefore of interest. Using human primary placental cells, we investigated the mechanism by which glucocorticoids stimulate placental CRH gene expression. Nuclear run-on transcription shows that in human placental cells glucocorticoids up-regulate transcription of human CRH (hCRH). Using transient transfection assays we demonstrate that dexamethasone up-regulates both basal and cAMP-stimulated hCRH promoter activity, correlating well with the increase in endogenous CRH peptide levels. Through mutagenesis and deletion analyses we show that dexamethasone stimulation of hCRH gene transcription requires a functional cAMP regulatory element (CRE); this CRE is adequate to confer dexamethasone stimulation upon a heterologous promoter, and electrophoretic mobility shift assay studies show that a placental nuclear protein specifically binds to the hCRH CRE.
AB - Production of placental CRH, which is identical to the peptide synthesized and secreted in the hypothalamus, has been linked to human parturition. Glucocorticoids stimulate placental CRH secretion and messenger ribonucleic acid expression, in contrast to their inhibition of CRH synthesis in the hypothalamus. A positive feedforward loop involving glucocorticoid-CRH-ACTH-glucocorticoid is thought to drive the exponential increase in placental CRH leading to delivery. Tissue-specific effects of glucocorticoids on CRH expression are therefore of interest. Using human primary placental cells, we investigated the mechanism by which glucocorticoids stimulate placental CRH gene expression. Nuclear run-on transcription shows that in human placental cells glucocorticoids up-regulate transcription of human CRH (hCRH). Using transient transfection assays we demonstrate that dexamethasone up-regulates both basal and cAMP-stimulated hCRH promoter activity, correlating well with the increase in endogenous CRH peptide levels. Through mutagenesis and deletion analyses we show that dexamethasone stimulation of hCRH gene transcription requires a functional cAMP regulatory element (CRE); this CRE is adequate to confer dexamethasone stimulation upon a heterologous promoter, and electrophoretic mobility shift assay studies show that a placental nuclear protein specifically binds to the hCRH CRE.
UR - http://www.scopus.com/inward/record.url?scp=0034456980&partnerID=8YFLogxK
U2 - 10.1210/jc.85.5.1937
DO - 10.1210/jc.85.5.1937
M3 - 文章
C2 - 10843178
AN - SCOPUS:0034456980
SN - 0021-972X
VL - 85
SP - 1937
EP - 1945
JO - Journal of Clinical Endocrinology and Metabolism
JF - Journal of Clinical Endocrinology and Metabolism
IS - 5
ER -