To elucidate the role of estradiol- 17β (E2) in the regulation of corpus luteum function
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ABSTRACT:
ORGANISM(S): Rattus norvegicus
PROVIDER: GSE41735 | GEO | 2012/10/23
SECONDARY ACCESSION(S): PRJNA178091
REPOSITORIES: GEO
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Project description:Corpus luteum (CL) is a transient endocrine tissue formed from the remnants of the ovarian follicle after ovulation. In response to gonadotropin surge, the ovulating follicle undergoes dramatic changes in expression of genes and differentiation of follicular cells into luteal cells. In several species, of the several genes that are down- regulated post ovulation, Cyp19A1 that codes for aromatase, essential for biosynthesis of estradiol- 17M-NM-2 (E2), also get down- regulated but appears to get up- regulated at later time points in the estrous cycle to have critical role in E2 secretion. In primates and rodents, higher expression and higher E2 levels has been observed in CL. Surprisingly, in the recently carried out gene expression profiling of PGF2M-NM-1- induced luteolysis studies in the bovine species [GSE27961], it was observed that expression of one of the earliest genes that was down- regulated was Cyp19A1 in the CL. However, the specific role of E2 in the regulation of CL function remains poorly defined. Thus, in the present study, efforts were made to examine the temporal changes in the global gene expression profile in the CL of pregnant rats after treatment with aromatase inhibitor (AI), Anastrozole, and E2 supplementation. The results obtained will further expand our knowledge on E2 target/responsive genes and the basic mechanism(s) that regulates the CL function. Key words: CL, E2, AI, Gene expression The objective of this study was to identify the effect of E2 deprivation and supplementation on CL function and temporal changes in the transcriptome of pregnant rat CL during day 12 to 16 of pregnancy following E2 deprivation by Anastrozole (AI, Aromatase inhibitor) treatment in pregnant rats, AI (1mg/ kg bw orally) treatment beginning on day 12 daily for 4 days. In the E2 supplementation experiments, together with AI, the rats were treated with E2 (10M-BM-5g/ day s.c.). CL tissues were collected on day 12 (no treatment; n=3 animals/ time point), day 16 (vehicle treatment; n=3 animals/ time point), day 16 (AI treatment; n=3 animals/ time point) and day 16 (AI+ E2 treatment; n=3 animals/ time point) to examine gene expression changes associated with E2 deprivation and recovery in the system. Following retrieval of CL from the ovary, corpora lutea were flash frozen in liquid nitrogen and stored at -70oC for the purpose of RNA isolation. The isolated RNA was labelled and hybridized to Affymetrix GeneChipM-BM-. Rat Gene 1.0 ST arrays as per the manufacturerM-bM-^@M-^Ys instructions.
2012-10-23 | E-GEOD-41735 | biostudies-arrayexpress
Project description:Background: Follicular growth and maturation in semi-synchronously spawning fish involve numerous cell signaling cascades and different molecular cascades are activated or inhibited during specific stages of oocyte development. The objectives of the current study were to identify molecular pathways and temporal gene expression patterns throughout a complete breeding cycle in female wild LMB to characterize the molecular sequence of events underlying follicle and ovary development. Methods: Microarray analysis was performed on eight morphologically distinct stages, from primary stages of oocyte growth to ovulation and atresia. Ovarian tissue histology, plasma vitellogenin, and sex steroids (E2 and T) were also measured to correlate molecular signaling cascades to higher levels of biological organization. Results: Global expression patterns revealed dramatic differences between early and late stages of ovarian follicle progression, with over 200 and 500 genes being differentially expressed during both ovulation and atresia respectively (p < 0.01). Time course analysis for all stages leading to ovulation and atresia identified increased expression of GABAA receptor subunits and peroxisome proliferator-activated receptor gamma during ovulation. Gene set enrichment analysis (GSEA) revealed that early stages of oocyte growth involved increases in pathways of natural killer cell and mast cell activation, as well as gap junction regulation. GSEA revealed that arachidonic acid metabolism was significantly up-regulated while CD2, fibronectin, and neuropeptides Y receptor signaling cascades were down-regulated at ovulation. Expression targets for LH signaling were decreased during vitellogenesis but increased at ovulation. GSEA revealed decreases in actin cytoskeleton regulation and receptor mediated signaling pathways involving TGF? and ephrin receptor regulation at atresia. Conclusions: This study offers new insight into the molecular pathways involved in vitellogenesis, ovulation and atresia in LMB and provides new hypotheses about the cellular pathways involved in oocyte growth and maturation. 31 microarrays on 8 unique stages of ovary development; developmental profile time course, development of LMB ovary
2011-12-20 | E-GEOD-32930 | biostudies-arrayexpress
Project description:A series of MCF-7 variants were previously developed that are estrogen-dependent for growth (MCF-7:WS8 cells), or resistant to estrogen deprivation/vulnerable to fast (MCF-7:5C) and delayed (MCF-7:2A) E2-inducible apoptosis. To identify miRNAs associated with aromatase inhibitor (AI)-resistance and vulnerability to E2-induced apoptosis, estrogen deprivation-resistant 5C and 2A cells were compared to estrogen-dependent WS8 cells and among each other.
2017-03-01 | GSE79326 | GEO
Project description:Approximately 75% of breast cancers express estrogen receptor α (ERα) and depend on estrogen signals for continued growth. Aromatase inhibitors (AIs) prevent estrogen production and inhibit estrogen receptor signaling, resulting in decreased cancer recurrence and mortality. Advanced tumors treated with AIs almost always develop resistance to these drugs via the up-regulation of alternative growth signals. The mechanisms that drive this resistance—especially epigenetic events that alter gene expression—are however not well understood. Here we performed a genome-wide DNA methylation and expression analysis of cell line models to find epigenetically regulated genes involved in acquired aromatase inhibitor resistance. We discovered that prostaglandin E2 receptor 4 (PTGER4) is up-regulated after demethylation and promotes phosphorylation and activation of ERα. Knockdown and inhibitor studies demonstrate that PTGER4 promotes AI resistance via ligand independent activation of the ERα-cofactor CARM1. We believe that we have discovered a novel epigenetic mechanism for altering cell signaling and acquiring endocrine therapy resistance. Our findings indicate that PTGER4 is a potential drug target in AI resistant cancers. Additionally, the epigenetic component of PTGER4 regulation suggests that further study of PTGER4 may yield valuable insights into how DNA methylation-targeted diagnoses and/or treatments can improve AI resistant breast cancer treatment.
2017-06-19 | GSE74942 | GEO
Project description:Approximately 75% of breast cancers express estrogen receptor α (ERα) and depend on estrogen signals for continued growth. Aromatase inhibitors (AIs) prevent estrogen production and inhibit estrogen receptor signaling, resulting in decreased cancer recurrence and mortality. Advanced tumors treated with AIs almost always develop resistance to these drugs via the up-regulation of alternative growth signals. The mechanisms that drive this resistance - especially epigenetic events that alter gene expression - are however not well understood. Here we performed a genome-wide DNA methylation and expression analysis of cell line models to find epigenetically regulated genes involved in acquired aromatase inhibitor resistance. We discovered that prostaglandin E2 receptor 4 (PTGER4) is up-regulated after demethylation and promotes phosphorylation and activation of ERα. Knockdown and inhibitor studies demonstrate that PTGER4 promotes AI resistance via ligand independent activation of the ERα-cofactor CARM1. We believe that we have discovered a novel epigenetic mechanism for altering cell signaling and acquiring endocrine therapy resistance. Our findings indicate that PTGER4 is a potential drug target in AI resistant cancers. Additionally, the epigenetic component of PTGER4 regulation suggests that further study of PTGER4 may yield valuable insights into how DNA methylation-targeted diagnoses and/or treatments can improve AI resistant breast cancer treatment.
2017-06-19 | GSE74941 | GEO
Project description:Background: Follicular growth and maturation in semi-synchronously spawning fish involve numerous cell signaling cascades and different molecular cascades are activated or inhibited during specific stages of oocyte development. The objectives of the current study were to identify molecular pathways and temporal gene expression patterns throughout a complete breeding cycle in female wild LMB to characterize the molecular sequence of events underlying follicle and ovary development. Methods: Microarray analysis was performed on eight morphologically distinct stages, from primary stages of oocyte growth to ovulation and atresia. Ovarian tissue histology, plasma vitellogenin, and sex steroids (E2 and T) were also measured to correlate molecular signaling cascades to higher levels of biological organization. Results: Global expression patterns revealed dramatic differences between early and late stages of ovarian follicle progression, with over 200 and 500 genes being differentially expressed during both ovulation and atresia respectively (p < 0.01). Time course analysis for all stages leading to ovulation and atresia identified increased expression of GABAA receptor subunits and peroxisome proliferator-activated receptor gamma during ovulation. Gene set enrichment analysis (GSEA) revealed that early stages of oocyte growth involved increases in pathways of natural killer cell and mast cell activation, as well as gap junction regulation. GSEA revealed that arachidonic acid metabolism was significantly up-regulated while CD2, fibronectin, and neuropeptides Y receptor signaling cascades were down-regulated at ovulation. Expression targets for LH signaling were decreased during vitellogenesis but increased at ovulation. GSEA revealed decreases in actin cytoskeleton regulation and receptor mediated signaling pathways involving TGFβ and ephrin receptor regulation at atresia. Conclusions: This study offers new insight into the molecular pathways involved in vitellogenesis, ovulation and atresia in LMB and provides new hypotheses about the cellular pathways involved in oocyte growth and maturation.
2011-12-20 | GSE32930 | GEO
Project description:Nylon microarrays displaying 9152 rainbow trout cDNAs were hybridized using RNA samples originating from ovarian tissue collected during late vitellogenesis, post-vitellogenesis and oocyte maturation. Differentially expressed genes were identified using a statistical analysis. A supervised clustering analysis was performed using only differentially expressed genes in order to identify gene clusters exhibiting similar expression profiles. In addition, specific genes were selected and their preovulatory ovarian expression was analyzed using real-time PCR. From the statistical analysis, 310 differentially expressed genes were identified. Among those genes, 90 were up-regulated at the time of oocyte maturation while 220 exhibited an opposite pattern. After clustering analysis, 90 clones belonging to 3 gene clusters exhibiting the most remarkable expression patterns were kept for further analysis. Using real-time PCR analysis, we observed a strong up-regulation of ion and water transport genes such as aquaporin 4 (aqp4) and pendrin (slc26). In addition, a dramatic up-regulation of vasotocin (avt) gene was observed. Furthermore, angiotensin-converting-enzyme 2 (ace2), coagulation factor V (cf5), adam 22, and the chemokine cxcl14 genes exhibited a sharp up-regulation at the time of oocyte maturation. Finally, ovarian aromatase (cyp19a1) exhibited a dramatic down-regulation over the post-vitellogenic period while a down-regulation of Cytidine monophosphate-N-acetylneuraminic acid hydroxylase (cmah) was observed at the time of oocyte maturation. We showed the over or under expression of more that 300 genes, most of them being previously unstudied or unknown in the fish preovulatory ovary. Our data confirmed the down-regulation of estrogen synthesis genes during the preovulatory period. In addition, the strong up-regulation of aqp4 and slc26 genes prior to ovulation suggests their participation in the oocyte hydration process occurring at that time. Furthermore, among the most up-regulated clones, several genes such as cxcl14, ace2, adam22, cf5 have pro-inflammatory, vasodilatory, proteolytics and coagulatory functions. The identity and expression patterns of those genes support the theory comparing ovulation to an inflammatory-like reaction. Late vitellogenesis: 3 samples Post-vitellogenesis: 4 samples Oocyte maturation (germinal vesicle breakdown): 6 samples
2010-07-01 | E-GEOD-4871 | biostudies-arrayexpress
Project description:To identify in clinical breast cancer those genes and pathways most associated with resistance to aromatase inhibitors by examining the global transcriptional effects of aromatase inhibitor (AI) treatment. Analysis of gene-expression measured in core-cut biopsies at baseline and surgery from patients received 2-week’s presurgical AI revealed: i) the molecular response to AI treatment varies greatly between patients, consistent with the variable clinical benefit from AI treatment; ii) higher baseline expression of an inflammatory signature is associated with poor antiproliferative response, and should be assessed further as a novel biomarker and potential target for AI-treated patients.
2020-06-29 | GSE153470 | GEO
Project description:The corpus luteum (CL), an ovarian transient gland, develops from the remnants of the ovulatory follicle and produces progesterone, required for maintenance of pregnancy in mammals. The development of the CL is characterized by the differentiation of granulosal and thecal cells into luteal cells, cell hypertrophy and hyperplasia. As the CL matures, growth ceases and the tissue acquires the ability to undergo regression in response to luteolytic signals (prostaglandin F2alpha). The regulators of this transition are poorly understood. MicroRNA, posttranscriptional regulators of tissue development and function, are hypothesized to play a role during these processes. The goal of this study was to profile the expression of microRNA (miRNA) in the corpus luteum (CL) of Holstein cows at two time points of the estrous cycle (early-cycle (Day4) and midcycle (D9-12); day0= day of estrus) in order to investigate their role in regulating CL development and function. Sample size = 6 animals and two time points (3 animals per time point). The aim was to compare the expression of miRNA between the early-cycle (Day4) and midcycle (days9-12) CL The three cows designated for early-cycle time point received an injection of gonadotropin releasing hormone (GnRH; Factrel; Zoetis, Florham Park, NJ) to synchronize the ovulation of a dominant follicle, and were slaughtered 4 days later to collect a day 4 CL. The three cows designated for midcycle time point were observed after CIDR removal to determine the onset of estrus, and on days 9-12 of the estrous cycle, the CL was collected by culpotomy.
2016-09-03 | E-GEOD-72733 | biostudies-arrayexpress
Project description:For premenopausal women with primary ER+ breast cancer, oophorectomy (OvX) is an evidence-based cost-effective option and is standard treatment in many countries. However, there is virtually no data describing the effects of OvX on breast tumour biology. We therefore characterized the endocrine and genome-wide transcriptional impact of OvX in 56 premenopausal women with ER+ breast cancer for two weeks prior to mastectomy. Plasma estradiol concentrations decreased from 421±305 to 24.1±24.5 pmol/l (mean±sd) 24 hours after OvX and to 8.8±7.3pmol/l two weeks later at mastectomy. Ki67 decreased in 33/36 (91.7%) tumours. The expression of 655 genes changed significantly (FDR<1%) with an absolute mean fold-change (FC) ≥1.25 (257 up, 398 down). Archetypal oestrogen-regulated genes, proliferation-associated genes and putative progesterone-regulated genes were strongly down-regulated. The gene expression changes did not differ according to HER2 status and correlated strongly with those after aromatase inhibitor (AI) treatment in 81 postmenopausal women. However, after OvX the mean FC was significantly higher compared to AI. In conclusion, changes in tumoural gene expression after OvX were largely similar but of a greater magnitude to those observed after AI in postmenopausal patients but OvX appeared to have a greater effect on progesterone-regulated genes than AI.
2018-02-14 | GSE97221 | GEO