Transcriptional effect of the LH surge in bovine granulosa cells during the peri-ovulation period

Abstract

The LH surge induces a multitude of events that are essential for ovulation and corpus luteum formation. The transcriptional responses to the LH surge of preovulatory granulosa cells (GCs) are complex and still poorly understood. In this study, a genome-wide bovine oligo array was used to determine how the gene expression profile of GCs is modulated by the LH surge. GCs from three different stages were used to assess the short-and long-term effects of this hormone on follicle differentiation: 1) 2 h before induction of the LH surge, 2) 6 h and 3) 22 h after the LH surge. The results obtained were a list of differentially expressed transcripts for each GC group. To provide a comprehensive understanding of the processes at play, biological annotations were used to reveal the different functions of transcripts, confirming that the LH surge acts in a temporal manner. The pre-LH group is involved in typical tasks such as cell division, development, and proliferation, while the early response to the LH surge included features such as response to stimulus, vascularization, and lipid synthesis, which are indicative of cells preparing for ovulation. The late response of GCs revealed terms associated with protein localization and intracellular transport, corresponding to the future secretion task that will be required for the transformation of GCs into corpus luteum. Overall, results described in this study provide new insights into the different transcriptional steps that GCs go through during ovulation and before luteinization.

Differential gene expression of granulosa cells after ovarian superstimulation in beef cattle

“…However, results of this study suggest that the multiple pre-ovulatory follicles that develop after superstimulation are not typical dominant follicles. The list of upregulated genes in the superstimulation group in this study is similar to those of other studies (Gilbert et al 2011(Gilbert et al , 2012 from dominant follicles before the LH surge at day 14 of the estrous cycle. It is important to note that the granulosa cells from our superstimulation group were collected 24 h after exogenous LH surge (i.e.…”

“…Little is known about the role of NTS in ovarian cells, but expression of NTS mRNA in granulosa and cumulus cells is high before the LH surge and decreases thereafter as ovulation approaches (Hernandez-Gonzalez et al 2006, Gilbert et al 2011. Based on the RT-PCR analysis, NTS was upregulated 7.6-fold (10-fold in microarrays data) after ovarian superstimulation, suggesting that treatment is associated with delay in cell differentiation and/or delayed follicular response to the LH surge.…”

“…NTS is known to mediate the positive feedback of E 2 on the gonadotrophin-releasing hormone (GNRH) neurons responsible for inducing the pre-ovulatory LH surge (Smith & Jennes 2001). NTS was thought to be localized exclusively in the nervous system, but results of recent studies document the presence of NTS mRNA in the ovaries (Hernandez-Gonzalez et al 2006, Kerr et al 2009, Gilbert et al 2011 Figure 3 Function analysis of gene expression of granulosa cells after superstimulation treatment based on log P value. The higher the log P value (taller bars), the more significant the function is.…”

Characterization of microRNAs differentially expressed during bovine follicle development

“…Each of these developmental steps involves sequential and profound changes in tissue structure and function, requiring finely tuned and coordinated changes in the expression of thousands of genes. Transcriptome analyses have identified many such genes during follicle selection, maturation, and the follicle-luteal transition (Gilbert et al 2011, Rao et al 2011, Christenson et al 2013, although relatively little is still known about the molecular mechanisms regulating their expression, particularly at the posttranscriptional level.…”

Gene expression profiling of granulosa cells from PCOS patients following varying doses of human chorionic gonadotropin

“…Rapid effects of LH on murine granulosa cells included 60 genes to be differentially expressed within 1 h following the Endothelin receptor type A; dual specificity phosphatase 1; guanine nucleotide binding protein (G protein), alpha 13; estrogen receptor 2 (ER beta); calcium/calmodulin-dependent protein kinase kinase 2, beta; regulator of G-protein signalling 3; phosphatidylinositol-specific phospholipase C, X domain containing 1; phospholipase D1, phosphatidylcholine-specific; natriuretic peptide receptor C; tetraspanin 6 Cell cycle (266) M-phase phosphoprotein 6; quiescin Q6 Cell division cycle associated 5 and 8; cell division cycle 25A and 25C; checkpoint suppressor 1; spindling; karyopherin alpha 2; kinetochore associated 1; nuclear transcription factor Y, gamma; M-phase phosphoprotein 1; nibrin hCG injection [8]. Gilbert et al [13] recently showed that over 3,000 transcripts were differentially expressed following LH surge in cows. Similarly, in the current study, hCG injections resulted in the modulation of thousands of genes.…”