scholarly journals Epigenetic Changes of the Cyp11a1 Promoter Region in Granulosa Cells Undergoing Luteinization During Ovulation in Female Rats

Endocrinology ◽  
2016 ◽  
Vol 157 (9) ◽  
pp. 3344-3354 ◽  
Author(s):  
Maki Okada ◽  
Lifa Lee ◽  
Ryo Maekawa ◽  
Shun Sato ◽  
Takuya Kajimura ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Granulosa Cells ◽  
Chromatin Immunoprecipitation ◽  
Promoter Region ◽  
Binding Protein ◽  
Female Rats ◽  
Proximal Promoter ◽  
Lh Surge ◽  
Enhancer Binding Protein

The ovulatory LH surge induces rapid up-regulation of Cyp11a1 in granulosa cells (GCs) undergoing luteinization during ovulation. This study investigated in vivo whether epigenetic controls including histone modifications and DNA methylation in the promoter region are associated with the rapid increase of Cyp11a1 gene expression after LH surge. GCs were obtained from rats treated with equine chorionic gonadotropin (CG) before (0 h) and 4 h and 12 h after human (h)CG injection. Cyp11a1 mRNA levels rapidly increased after hCG injection, reached a peak at 4 hours, and then remained elevated until 12 hours. DNA methylation status in the Cyp11a1 proximal promoter region was hypomethylated and did not change at any of the observed times after hCG injection. Chromatin immunoprecipitation assays revealed that the levels of trimethylation of lysine 4 on histone H3 (H3K4me3), an active mark for transcription, increased, whereas the levels of H3K9me3 and H3K27me3, which are marks associated with repression of transcription, decreased in the Cyp11a1 proximal promoter after hCG injection. Chromatin condensation, which was analyzed using deoxyribonuclease I, decreased in the Cyp11a1 proximal promoter after hCG injection. Chromatin immunoprecipitation assays also showed that the binding activity of CAATT/enhancer-binding protein-β to the Cyp11a1 proximal promoter increased after hCG injection. Luciferase assays revealed that the CAATT/enhancer-binding protein-β-binding site had transcriptional activity and contributed to basal and cAMP-induced Cyp11a1 expression. These results suggest that changes in histone modification and chromatin structure in the Cyp11a1 proximal promoter are involved in the rapid increase of Cyp11a1 gene expression in GCs undergoing luteinization during ovulation.

scholarly journals CCAAT/Enhancer Binding Protein β2 Is Involved in Growth Hormone-Regulated Insulin-Like Growth Factor-II Gene Expression in the Liver of Rainbow Trout (Oncorhynchus mykiss)

Endocrinology ◽  
2010 ◽  
Vol 151 (5) ◽  
pp. 2128-2139 ◽  
Author(s):  
Jay H. Lo ◽  
Thomas T. Chen
Keyword(s):  
Gene Expression ◽  
Rainbow Trout ◽  
Binding Protein ◽  
Regulatory Region ◽  
Negative Regulator ◽  
Proximal Promoter ◽  
Gh Treatment ◽  
Enhancer Binding Protein ◽  
Histone H4 Acetylation ◽  
Ccaat Enhancer Binding Protein

Previously, we showed that levels of different CCAAT/enhancer binding protein (C/EBP) mRNAs in the liver of rainbow trout were modulated by GH and suggested that C/EBPs might be involved in GH-induced IGF-II gene expression. As a step toward further investigation, we have developed monospecific polyclonal antibodies to detect rainbow trout C/EBPα, -β1, -β2, and -δ2 isoform proteins. Injection of GH into adult rainbow trout resulted in a significant increase of C/EBPβ1, C/EBPβ2, and C/EBPδ2 proteins in the liver. Chromatin immunoprecipitation analysis revealed that C/EBPβ2 binds to multiple sites at the 5′ promoter/regulatory region, introns, and the 3′ untranslated region of the IGF-II gene. GH treatment reduced C/EBPβ2 binding to several of these regions at 6 h after injection. The decreased occupancy of C/EBPβ2 coincided well with an increase of histone H4 acetylation at the proximal promoter and elevation of the IGF-II mRNA level. Immunoblotting analysis showed that C/EBPβ2 existed predominately as a truncated form in the liver, and cotransfection analysis further showed that the truncated C/EBPβ2 acted as a negative regulator on IGF-II proximal promoter. GH treatment caused deacetylation of C/EBPβ2 in the liver. In addition, we observed a GH-dependent interaction of C/EBPβ2 with a complex involving histone H1. All together, these results suggest that C/EBPβ2 was regulated at multiple levels by GH, and C/EBPβ2 may play a suppressive role in mediating GH-induced IGF-II expression in the liver of rainbow trout.

scholarly journals Changes in Histone Modification and DNA Methylation of the StAR and Cyp19a1 Promoter Regions in Granulosa Cells Undergoing Luteinization during Ovulation In Rats

Endocrinology ◽  
2013 ◽  
Vol 154 (1) ◽  
pp. 458-470 ◽  
Author(s):  
Lifa Lee ◽  
Hiromi Asada ◽  
Fumie Kizuka ◽  
Isao Tamura ◽  
Ryo Maekawa ◽  
...  
Keyword(s):  
Gene Expression ◽  
Histone Modifications ◽  
Granulosa Cells ◽  
Chromatin Immunoprecipitation ◽  
Binding Protein ◽  
Mrna Levels ◽  
Chromatin Immunoprecipitation Assay ◽  
Immunoprecipitation Assay ◽  
Rapid Changes

The ovulatory LH surge induces rapid up-regulation of steroidogenic acute regulatory (StAR) protein and rapid down-regulation of aromatase (Cyp19a1) in granulosa cells (GCs) undergoing luteinization during ovulation. This study investigated in vivo whether epigenetic mechanisms including histone modifications are involved in the rapid changes of StAR and Cyp19a1 gene expression. GCs were obtained from rats treated with equine chorionic gonadotropin (CG) before (0 h) and after human (h)CG injection. StAR mRNA levels rapidly increased after hCG injection, reached a peak at 4 h, and then remained higher compared with 0 h until 12 h. Cyp19a1 mRNA levels gradually decreased after hCG injection and reached their lowest level at 12 h. A chromatin immunoprecipitation assay revealed that levels of histone-H4 acetylation (Ac-H4) and trimethylation of histone-H3 lysine-4 (H3K4me3) increased whereas H3K9me3 and H3K27me3 decreased in the StAR promoter after hCG injection. On the other hand, the levels of Ac-H3 and -H4 and H3K4me3 decreased, and H3K27me3 increased in the Cyp19a1 promoter after hCG injection. Chromatin condensation, which was analyzed using deoxyribonuclease I, decreased in the StAR promoter and increased in the Cyp19a1 promoter after hCG injection. A chromatin immunoprecipitation assay also showed that binding activities of CAATT/enhancer-binding protein β to the StAR promoter increased and binding activities of phosphorylated-cAMP response element binding protein to the Cyp19a1 promoter decreased after hCG injection. These results provide in vivo evidence that histone modifications are involved in the rapid changes of StAR and Cyp19a1 gene expression by altering chromatin structure of the promoters in GCs undergoing luteinization during ovulation.

scholarly journals The Increase in Signaling by Kisspeptin Neurons in the Preoptic Area and Associated Changes in Clock Gene Expression That Trigger the LH Surge in Female Rats Are Dependent on the Facilitatory Action of a Noradrenaline Input

Endocrinology ◽  
2016 ◽  
Vol 157 (1) ◽  
pp. 323-335 ◽  
Author(s):  
Bruna Kalil ◽  
Aline B. Ribeiro ◽  
Cristiane M. Leite ◽  
Ernane T. Uchôa ◽  
Ruither O. Carolino ◽  
...  
Keyword(s):  
Gene Expression ◽  
Median Eminence ◽  
Preoptic Area ◽  
Clock Genes ◽  
Third Ventricle ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Lh Surge ◽  
Clock Gene Expression

Abstract In rodents, kisspeptin neurons in the rostral periventricular area of the third ventricle (RP3V) of the preoptic area are considered to provide a major stimulatory input to the GnRH neuronal network that is responsible for triggering the preovulatory LH surge. Noradrenaline (NA) is one of the main modulators of GnRH release, and NA fibers are found in close apposition to kisspeptin neurons in the RP3V. Our objective was to interrogate the role of NA signaling in the kisspeptin control of GnRH secretion during the estradiol induced LH surge in ovariectomized rats, using prazosin, an α1-adrenergic receptor antagonist. In control rats, the estradiol-induced LH surge at 17 hours was associated with a significant increase in GnRH and kisspeptin content in the median eminence with the increase in kisspeptin preceding that of GnRH and LH. Prazosin, administered 5 and 3 hours prior to the predicted time of the LH surge truncated the LH surge and abolished the rise in GnRH and kisspeptin in the median eminence. In the preoptic area, prazosin blocked the increases in Kiss1 gene expression and kisspeptin content in association with a disruption in the expression of the clock genes, Per1 and Bmal1. Together these findings demonstrate for the first time that NA modulates kisspeptin synthesis in the RP3V through the activation of α1-adrenergic receptors prior to the initiation of the LH surge and indicate a potential role of α1-adrenergic signaling in the circadian-controlled pathway timing of the preovulatory LH surge.

DDRE-30. CELL-PENETRATING PEPTIDE ANTAGONIST OF CCAAT/ENHANCER BINDING PROTEIN ß DISPLAYS POTENT ANTI-GLIOBLASTOMA ACTIVITY

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi80-vi81
Author(s):  
Jim Rotolo ◽  
Lila Ghamsari ◽  
Ricardo Ramierez ◽  
Mark Koester ◽  
Siok Leong ◽  
...  
Keyword(s):  
Gene Expression ◽  
Leucine Zipper ◽  
Binding Protein ◽  
Xenograft Model ◽  
Mesenchymal Transition ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein ◽  
Subcutaneous Xenograft ◽  
Peptide Antagonist ◽  
Anti Tumor Activity

Abstract CCAAT/Enhancer Binding Protein Beta (C/EBPß) is a transcription factor overexpressed in glioblastoma (GBM). Mechanistically, C/EBPß is a master regulator of mesenchymal transition in GBM, and its increased expression correlates with mesenchymal differentiation and predicts poor clinical outcome. C/EBPß activity requires dimerization with co-factors such as CREB/ATF family members via leucine zipper interactions. ST101 is a novel peptide antagonist of C/EBPß currently being evaluated in a Phase 1/2 clinical study in patients with advanced unresectable and metastatic solid tumors. ST101 binds to the C/EBPß leucine zipper, thereby preventing dimer formation and inhibiting its transcriptional activity, resulting in selective tumor cell cytotoxicity. Here, we describe ST101 non-clinical anti-tumor activity against GBM. In vitro studies in T98G and U251 cells demonstrate ST101 dose-dependent impact of cell viability (EC50 of 2.2 and 1.2 μM, respectively), accompanied by significant impact on C/EBPß-mediated gene expression as determined by qPCR analysis. In contrast, normal human mononuclear and epithelial cells were not sensitive to ST101 (EC50 > 80 μM). In vivo, ST101 displayed significant anti-tumor activity in a U251 GBM subcutaneous xenograft model, resulting in 81.4% tumor growth inhibition (TGI) vs. control and undetectable tumors in 50% of animals. Following ST101 exposure tumors displayed reduced BIRC3 and ID2 gene expression, and significantly increased cleaved caspase 3 immunostaining indicative of cell death induction. In U251 tumors, subtherapeutic ST101 (< 5% TGI) in combination with temozolomide (< 5% TGI) resulted in 52.8% TGI, significantly greater than either single-agent alone. Similarly, in a temozolomide-refractory T98G GBM subcutaneous xenograft model, ST101 (41.6% TGI) in combination with TMZ (< 5% TGI) resulted in significant anti-GBM response (72.4% TGI). These data emphasize the potential of ST101 as a potent peptide therapeutic for GBM.

scholarly journals Gene Expression of CCAAT/Enhancer-Binding Protein .DELTA. Mediated by Autoregulation Is Repressed by Related Gene Family Proteins.

2000 ◽  
Vol 23 (12) ◽  
pp. 1424-1429 ◽  
Author(s):  
Atsuhiro TANABE ◽  
Chizumi KUMAHARA ◽  
Shigehiro OSADA ◽  
Tsutomu NISHIHARA ◽  
Masayoshi IMAGAWA
Keyword(s):  
Gene Expression ◽  
Gene Family ◽  
Binding Protein ◽  
Related Gene ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein
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