Transcriptome datasets of ESR2-regulated genes in rat granulosa cells during gonadotropin-induced follicle maturation.

Disruption of estrogen receptor beta (ESR2) dysregulates granulosa cell genes essential for follicle maturation and ovulation. The datasets presented in this article depict gonadotropin-induced genes, which are differentially expressed in Esr2-null rat granulosa cells. Synchronized follicle development was initiated in four-week-old wildtype and Esr2-null female rats by administration of PMSG. Forty-eight hours after PMSG injection, further maturation of ovarian follicles was induced by hCG treatment. Granulosa cells were collected from the ovaries before gonadotropin administration, 48 h after PMSG treatment, and 4 h after hCG injection to the PMSG-treated rats. Total RNA was purified from granulosa cells and whole transcriptome was assessed by RNA-sequencing on an Illumina HiSeq X platform. RNA-seq data of wildtype and Esr2-null granulosa cells were analyzed and differentially expressed genes were identified by CLC Genomics Workbench. Gonadotropin-induced genes were identified by comparing the transcriptome data of PMSG- or hCG-induced wildtype granulosa cells with those without gonadotropin treatment. Furthermore, differentially expressed genes in Esr2-null granulosa cells were determined by comparing the transcriptome data with that of wildtype granulosa cells. These datasets can be used to recognize the gonadotropin-induced genes in granulosa cells that are Esr2-regulated and important for ovarian follicle maturation.

Transcriptome datasets of gonadotropin-induced ESR2-regulated genes in rat oocytes.

Disruption of estrogen receptor beta (ESR2) dysregulates oocyte maturation, which leads to failure of ovulation. We investigated ESR2-regulated genes during gonadotropin-induced oocyte maturation using RNA-sequencing. Through the administration of pregnant mare's serum gonadotropin (PMSG), synchronized follicle development was initiated in four-week-old wildtype and Esr2-null female rats. Forty-eight hours after the PMSG injection, human chorionic gonadotropin (hCG) was used for further maturation. Oocytes were collected from the ovaries 4 h after hCG injection. The total RNA was isolated from the oocytes and the whole oocyte transcriptome was determined by RNA-sequencing on the Illumina HiSeq4000 sequencer. RNA-sequencing data of wildtype and Esr2-null oocytes were analyzed, and differentially expressed genes were identified using the CLC Genomics Workbench. Whole oocyte transcriptome data of wildtype and Esr2-null oocytes were compared to identify the differentially expressed genes. Raw data are deposited to the NCBI Sequence Read Archive (SRA) and analyzed data are presented in this data article. These datasets can be utilized to identify the gonadotropin-induced genes in oocytes that are ESR2-regulated and important to oocyte maturation.

Liver transcriptome data of Esr1 knockout male rats reveals altered expression of genes involved in carbohydrate and lipid metabolism.

Estrogens are traditionally considered to be female sex steroid hormones and most of the studies examining estrogen regulation of metabolic function in the liver have been conducted in females. However, the liver expresses high levels of estrogen receptor alpha (ESR1) in both males and females, which mediates the hepatic response to estrogens. In this data article, we investigated whether metabolic disorders in Esr1 knockout (Esr1-/-) male rats were linked with loss of transcriptional regulation by ESR1 in liver. To identify the ESR1 regulated genes in the mutant liver, RNA-sequencing was performed on liver RNAs purified from young male rats. The raw data were analyzed using the CLC Genomics Workbench and high-quality RNA-sequencing reads were aligned to the Rattus norvegicus genome. Transcriptome data obtained from Esr1-/- liver RNAs were compared to that of wild type rats. Based on an absolute fold change of 2 with a p-value ≤ 0.05, a total of 618 differentially expressed genes were identified in the Esr1-/- male liver. Pathway analyses demonstrated that the majority of differentially expressed genes are regulators of carbohydrate and lipid metabolism in the liver. These differentially expressed genes and their potential roles were further examined in a companion manuscript, "Disruption of ESR1 alters the expression of genes regulating hepatic lipid and carbohydrate metabolism in male rats" (Khristi et al., 2018).

Disruption of ESR1 alters the expression of genes regulating hepatic lipid and carbohydrate metabolism in male rats.

The liver helps maintain energy homeostasis by synthesizing and storing glucose and lipids. Gonadal steroids, particularly estrogens, play an important role in regulating metabolism. As estrogens are considered female hormones, metabolic disorders related to the disruption of estrogen signaling have mostly been studied in females. Estrogen receptor alpha (ESR1) is the predominant receptor in both the male and female liver, and it mediates the hepatic response to estrogens. Loss of ESR1 increases weight gain and obesity in female rats, while reducing the normal growth in males. Although Esr1-/- male rats have a reduced body weight, they exhibit increased adipose deposition and impaired glucose tolerance. We further investigated whether these metabolic disorders in Esr1-/- male rats were linked with the loss of transcriptional regulation by ESR1 in the liver. To identify the ESR-regulated genes, RNA-sequencing was performed on liver mRNAs from wildtype and Esr1-/- male rats. Based on an absolute fold change of ≥2 with a p-value ≤ 0.05, a total of 706 differentially expressed genes were identified in the Esr1-/- male liver: 478 downregulated, and 228 upregulated. Pathway analyses demonstrate that the differentially expressed genes include transcriptional regulators (Cry1, Nr1d1, Nr0b2), transporters (Slc1a2), and regulators of biosynthesis (Cyp7b1, Cyp8b1), and hormone metabolism (Hsd17b2, Sult1e1). Many of these genes are also integral parts of the lipid and carbohydrate metabolism pathways in the liver. Interestingly, certain critical regulators of the metabolic pathways displayed a sexual dimorphism in expression, which may explain the divergent weight gain in Esr1-/- male and female rats despite common metabolic dysfunctions.

ESR2 Is Essential for Gonadotropin-Induced Kiss1 Expression in Granulosa Cells.

Hypothalamic expression of Kiss1 plays an essential role in the onset of puberty, gonadal development, and ovulation. Estrogens regulate the expression of Kiss1 in the hypothalamus through estrogen receptor-α. Kiss1 is also expressed in the ovary, where its expression correlates with the onset of puberty and progression of the estrous cycle. To date, estrogen regulation of Kiss1 expression in the ovary has not been investigated. We recently observed that gonadotropin-induced Kiss1 expression was absent in Esr2-null rat ovaries even though Esr1 was present. Wild-type granulosa cells abundantly expressed Kiss1 and oocytes expressed the Kiss1 receptor. We characterized estrogen receptor-ß (ESR2) regulation of Kiss1 expression in granulosa cells by identifying granulosa cell-specific transcript variants and potential regulatory regions. The Kiss1 promoter, an upstream enhancer, and a downstream enhancer all possessed conserved estrogen response elements (EREs) and showed active histone marks in gonadotropin-stimulated granulosa cells. The transcriptionally active Kiss1 promoter, as well as the enhancers, also revealed enrichment for ESR2 binding. Furthermore, activity of a Kiss1 promoter construct was induced after overexpression of ESR2 and was blocked upon mutation of an ERE within the promoter. Finally, pregnant mare serum gonadotropin and human chorionic gonadotropin administration induced phosphorylation of ESR2 and upregulated the AP-1 proteins FOSL2 and JUNB in granulosa cells. Activated MAPK ERK2 was associated with the ESR2 phosphorylation in granulosa cells, and AP-1 factors could synergistically activate the Kiss1 promoter activity. These gonadotropin-induced changes paralleled Kiss1 expression in granulosa cells. We conclude that gonadotropin-stimulated Kiss1 expression in granulosa cells is dependent on both the activation of ESR2 and the upregulation of AP-1.