Coordinate Regulation of Neuropeptide Y and Agouti-Related Peptide Gene Expression by Estrogen Depends on the Ratio of Estrogen Receptor (ER) α to ERβ in Clonal Hypothalamic Neurons
| Autor: | Danny Titolo, Denise D. Belsham, Fang Cai |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
medicine.medical_specialty
medicine.drug_class Hypothalamus Gene Expression Estrogen receptor Gonadotropin-releasing hormone Biology Cell Line Mice Endocrinology Internal medicine mental disorders medicine Animals Estrogen Receptor beta Humans Agouti-Related Protein Neuropeptide Y RNA Messenger Molecular Biology Estrogen receptor beta Neurons Gene knockdown digestive oral and skin physiology Estrogen Receptor alpha Estrogens General Medicine Neuropeptide Y receptor Peptide Fragments humanities nervous system Estrogen Estrogen receptor alpha Agouti-related peptide Biomarkers hormones hormone substitutes and hormone antagonists |
| Zdroj: | Molecular Endocrinology. 20:2080-2092 |
| ISSN: | 1944-9917 0888-8809 |
| Popis: | Neuropeptide Y (NPY) and agouti-related peptide (AgRP) stimulate feeding, whereas NPY also facilitates the estrogen-mediated preovulatory GnRH surge. In addition to regulating reproductive function, estrogen also acts as an anorexigenic hormone, although it is not yet known which hypothalamic neurons are involved in this process. We hypothesize that estrogen may directly control hypothalamic NPY and/or AgRP synthesis to influence energy homeostasis. Using two clonal, murine hypothalamic neuronal cell models, N-38 and N-42, we demonstrate that 17beta-estradiol differentially regulates estrogen receptor (ER)alpha and ERbeta levels, as well as NPY and AgRP gene expression in a manner that is temporally coordinated with the changes in ER abundance. The estrogen-mediated repression of NPY and AgRP mRNA levels in N-38 and N-42 neurons require either ERalpha and ERbeta or ERalpha alone, respectively, whereas the induction of NPY and AgRP in N-38 neurons is strictly ERbeta dependent, as assessed by ER-specific agonists and small interfering RNA knockdown of ERalpha or ERbeta. Through transient transfection analysis in N-38 neurons, we have mapped the estrogen-mediated repression of NPY to within -1078 of the 5' regulatory region of the NPY gene. Our results provide the first evidence that NPY and AgRP gene expression is directly regulated by estrogen in specific hypothalamic neurons, and that this regulation is dependent upon the ratio of ERbeta to ERalpha. The biphasic control of neuronal NPY/AgRP transcription may be a mechanism by which estrogen has distinct effects on both energy homeostasis and reproduction. |
| Databáze: | OpenAIRE |
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