scholarly journals ERβ Regulation of Gonadotropin Responses during Folliculogenesis

2021 ◽  
Vol 22 (19) ◽  
pp. 10348
Author(s):  
Eun B. Lee ◽  
V. Praveen Chakravarthi ◽  
Michael W. Wolfe ◽  
M. A. Karim Rumi

Gonadotropins are essential for regulating ovarian development, steroidogenesis, and gametogenesis. While follicle stimulating hormone (FSH) promotes the development of ovarian follicles, luteinizing hormone (LH) regulates preovulatory maturation of oocytes, ovulation, and formation of corpus luteum. Cognate receptors of FSH and LH are G-protein coupled receptors that predominantly signal through cAMP-dependent and cAMP-independent mechanisms that activate protein kinases. Subsequent vital steps in response to gonadotropins are mediated through activation or inhibition of transcription factors required for follicular gene expression. Estrogen receptors, classical ligand-activated transcriptional regulators, play crucial roles in regulating gonadotropin secretion from the hypothalamic–pituitary axis as well as gonadotropin function in the target organs. In this review, we discuss the role of estrogen receptor β (ERβ) regulating gonadotropin response during folliculogenesis. Ovarian follicles in Erβ knockout (ErβKO) mutant female mice and rats cannot develop beyond the antral state, lack oocyte maturation, and fail to ovulate. Theca cells (TCs) in ovarian follicles express LH receptor, whereas granulosa cells (GCs) express both FSH receptor (FSHR) and LH receptor (LHCGR). As oocytes do not express the gonadotropin receptors, the somatic cells play a crucial role during gonadotropin induced oocyte maturation. Somatic cells also express high levels of estrogen receptors; while TCs express ERα and are involved in steroidogenesis, GCs express ERβ and are involved in both steroidogenesis and folliculogenesis. GCs are the primary site of ERβ-regulated gene expression. We observed that a subset of gonadotropin-induced genes in GCs, which are essential for ovarian follicle development, oocyte maturation and ovulation, are dependent on ERβ. Thus, ERβ plays a vital role in regulating the gonadotropin responses in ovary.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shauna Kehoe ◽  
Katarina Jewgenow ◽  
Paul R. Johnston ◽  
Susan Mbedi ◽  
Beate C. Braun

AbstractIn vitro growth (IVG) of dormant primordial ovarian follicles aims to produce mature competent oocytes for assisted reproduction. Success is dependent on optimal in vitro conditions complemented with an understanding of oocyte and ovarian follicle development in vivo. Complete IVG has not been achieved in any other mammalian species besides mice. Furthermore, ovarian folliculogenesis remains sparsely understood overall. Here, gene expression patterns were characterised by RNA-sequencing in primordial (PrF), primary (PF), and secondary (SF) ovarian follicles from Felis catus (domestic cat) ovaries. Two major transitions were investigated: PrF-PF and PF-SF. Transcriptional analysis revealed a higher proportion in gene expression changes during the PrF-PF transition. Key influencing factors during this transition included the interaction between the extracellular matrix (ECM) and matrix metalloproteinase (MMPs) along with nuclear components such as, histone HIST1H1T (H1.6). Conserved signalling factors and expression patterns previously described during mammalian ovarian folliculogenesis were observed. Species-specific features during domestic cat ovarian folliculogenesis were also found. The signalling pathway terms “PI3K-Akt”, “transforming growth factor-β receptor”, “ErbB”, and “HIF-1” from the functional annotation analysis were studied. Some results highlighted mechanistic cues potentially involved in PrF development in the domestic cat. Overall, this study provides an insight into regulatory factors and pathways during preantral ovarian folliculogenesis in domestic cat.


2015 ◽  
Vol 27 (2) ◽  
pp. 407 ◽  
Author(s):  
Karen L. Kind ◽  
Kimberley K. Y. Tam ◽  
Kelly M. Banwell ◽  
Ashley D. Gauld ◽  
Darryl L. Russell ◽  
...  

Oxygen is an important component of the environment of the cumulus–oocyte complex (COC), both in vivo within the ovarian follicle and during in vitro oocyte maturation (IVM). Cumulus cells have a key role in supporting oocyte development, and cumulus cell function and gene expression are known to be altered when the environment of the COC is perturbed. Oxygen-regulated gene expression is mediated through the actions of the transcription factors, the hypoxia-inducible factors (HIFs). In the present study, the effect of oxygen on cumulus cell gene expression was examined following in vitro maturation of the murine COC at 2%, 5% or 20% oxygen. Increased expression of HIF-responsive genes, including glucose transporter-1, lactate dehydrogenase A and BCL2/adenovirus E1B interacting protein 3, was observed in cumulus cells matured at 2% or 5%, compared with 20% oxygen. Stabilisation of HIF1α protein in cumulus cells exposed to low oxygen was confirmed by western blot and HIF-mediated transcriptional activity was demonstrated using a transgenic mouse expressing green fluorescent protein under the control of a promoter containing hypoxia response elements. These results indicate that oxygen concentration influences cumulus cell gene expression and support a role for HIF1α in mediating the cumulus cell response to varying oxygen.


2019 ◽  
Vol 191 (12) ◽  
pp. 60-64
Author(s):  
Tatiana Stanislavovich ◽  
T. I. KUZMINA ◽  
Aleksey Molchanov

Abstract. Currently, there is the possibility of more detailed studies to the study of oocytes and somatic cells (granulosa cells). The possibility to develop successful models of maturation of female gametes defines the possibility to improve existing methods for the selection of donor eggs and the search for new donor eggs. Oocyte maturation in vivo occurs with the participation of structural follicle elements and follicular fluid [3, 4, 6]. Granulosa cells are widely used in bovine oocyte maturation systems and used in cloning and transgenesis technologies [8, 13]. Purpose of this study: to perform destructive changes granulosa cells in ovarian follicles of bovines (Ø 3–5 mm),which contain growing(ВСВ–) or completed the growth phase of oocytes (ВСВ+). Methods: Functional testing of oocytes wascarried out using the vital dye BCB (brillant cresyl blue – diamond crystal blue) [10]. Viability indices in granulosa cells isolated from follicles that contain oocyte s that grow or complete the growth phase were determined by flow cytometry. The result. It was found, that cellsof granulosa from cow follicles are characterized by different indicators of apoptosis levels depending on the status of oocytes (completed growth and growing) isolated from these follicles. The proportion of apoptotic granulosa cells in bovine follicles of containing oocytes that completed the growth phase, exceeded that in follicles containing growing oocytes by 11 % (29 % vs. 18 %, c:dP < 0.05). The scientific novelty: The data obtained using flow cytometry, allow us to evaluate the level of apoptosis in granulosa cells of bovine ovarian follicle as indicator of functional status of developing oocytes (growing or completed growth phases). This indicator can be used in prognosis of competencies for maturation of bovine oocytes.


1995 ◽  
Vol 61 (1) ◽  
pp. 57-62 ◽  
Author(s):  
J. A. Abecia ◽  
S. M. Rhind ◽  
T. A. Bramley ◽  
S. R. McMillen

AbstractTwo groups of eives were fed to provide 1·5 × (high, H; no. = 13) or 0·5 × (low, L; no. = 12) energy requirements for maintenance of live weight from 12 days before a synchronized mating in November until slaughter at 14 days after mating and the effects on embryo survival and associated patterns of gonadotropin secretion, and ovarian follicle and corpus luteum function were investigated. Proportionately, there were more pregnant ewes in the H group than the L group (0·62 v. 0·08; %2 = 7·67; P < 0·01) at day 14 of pregnancy but there were no differences in mean LH concentrations, LH pulse frequencies or amplitudes, either before mating and ovulation (follicular phase) or at day 10 after mating (luteal phase). The mean size (mm) of the three largest follicles (H: 5·69; L: 5·65; s.e.d. = 0·21), the proportion of these follicles that were oestrogenic (secreting > 500 pg oestradiol per h; H: 0·29; L: 0·28; y) = 0·01; P > 0·05) and secretion (pg/h) in vitro of oestradiol (H, 294; L, 386; s.e.d. = 146) (pg/h) and testosterone (H: 636; L: 508; s.e.d. = 293) by these follicles were similar for both treatments. There were no treatment differences in LH receptor concentrations (pg hormone bound per mg protein) in granulosa (H: 69·02; L: 67·76; s.e.d. = 0·20) and thecal (H: 46-88; L: 50·82; s.e.d. = 0·19) tissues. However, there was a higher concentration of receptors in the thecal tissue of oestrogenic follicles ofL than H ewes (167 v. 62; s.e.d. = 18; P < 0·05). Mean weights (g) of corpora lutea (H: 0·72; L: 0·59; s.e.d. = 0·003; P = 0·09), progesterone secretion (ng/mg per h) in vitro by luteal tissue (H: 1·75; L: 1·78; s.e.d. = 0·30) and LH receptor concentrations in corpora lutea (H: 58·16; L: 54·27; s.e.d. = 25·14) were similar for both treatments. It is concluded that the reduction in embryo survival associated with a reduced level of food intake was not attributable to a reduction in LH secretion, inadequacies in follicle growth and development or in the capacity of the corpora lutea to synthesize and release progesterone.


1998 ◽  
Vol 21 (2) ◽  
pp. 179-187 ◽  
Author(s):  
KM Ohleth ◽  
Q Zhang ◽  
CA Bagnell

Relaxin production by the ovarian follicle of gonadotropin-primed, prepubertal gilts is well documented. As far as we are aware, a source of relaxin in pig follicles, independent of gonadotropins, has not yet been reported. Therefore, the objective of this study was to determine whether relaxin is produced in porcine follicles in the absence of exogenous or cyclic gonadotropins. In immature pigs, immunoreactive relaxin was detected in fluids from small (1-3 mm), medium (4-5 mm) and large (>6 mm) follicles and localized to the theca interna of large follicles. Relaxin levels in follicular fluid significantly increased with follicle size (P<0.05). Relaxin mRNA was detected in whole small- and medium-sized follicles. In large follicles, the relaxin gene was expressed in thecal layers, but not granulosa cells. The abundance of relaxin transcript did not change with follicle size. In summary, relaxin protein and mRNA were detected in porcine follicles from immature animals, indicating that relaxin is produced in the porcine follicle in the absence of exogenous or cyclic gonadotropins. Relaxin's in vitro growth effects on porcine granulosa and theca cells support this follicular relaxin as a growth modulator during porcine follicular development.


2006 ◽  
Vol 73 ◽  
pp. 85-96 ◽  
Author(s):  
Richard J. Reece ◽  
Laila Beynon ◽  
Stacey Holden ◽  
Amanda D. Hughes ◽  
Karine Rébora ◽  
...  

The recognition of changes in environmental conditions, and the ability to adapt to these changes, is essential for the viability of cells. There are numerous well characterized systems by which the presence or absence of an individual metabolite may be recognized by a cell. However, the recognition of a metabolite is just one step in a process that often results in changes in the expression of whole sets of genes required to respond to that metabolite. In higher eukaryotes, the signalling pathway between metabolite recognition and transcriptional control can be complex. Recent evidence from the relatively simple eukaryote yeast suggests that complex signalling pathways may be circumvented through the direct interaction between individual metabolites and regulators of RNA polymerase II-mediated transcription. Biochemical and structural analyses are beginning to unravel these elegant genetic control elements.


2020 ◽  
Author(s):  
Robert Calin-Jageman ◽  
Irina Calin-Jageman ◽  
Tania Rosiles ◽  
Melissa Nguyen ◽  
Annette Garcia ◽  
...  

[[This is a Stage 1 Registered Report manuscript. The project was submitted for review to eNeuro. Upon revision and acceptance, this version of the manuscript was pre-registered on the OSF (9/11/2019, https://osf.io/fqh8j) (but due to an oversight not posted as a preprint until July 2020). A Stage 2 manuscript is now posted as a pre-print (https://psyarxiv.com/h59jv) and is under review at eNeuro. A link to the final Stage 2 manuscript will be added when available.]]There is fundamental debate about the nature of forgetting: some have argued that it represents the decay of the memory trace, others that the memory trace persists but becomes inaccessible due to retrieval failure. These different accounts of forgetting make different predictions about savings memory, the rapid re-learning of seemingly forgotten information. If forgetting is due to decay then savings requires re-encoding and should thus involve the same mechanisms as initial learning. If forgetting is due to retrieval-failure then savings should be mechanistically distinct from encoding. In this registered report we conducted a pre-registered and rigorous test between these accounts of forgetting. Specifically, we used microarray to characterize the transcriptional correlates of a new memory (1 day from training), a forgotten memory (8 days from training), and a savings memory (8 days from training but with a reminder on day 7 to evoke a long-term savings memory) for sensitization in Aplysia californica (n = 8 samples/group). We find that the transcriptional correlates of savings are [highly similar / somewhat similar / unique] relative to new (1-day-old) memories. Specifically, savings memory and a new memory share [X] of [Y] regulated transcripts, show [strong / moderate / weak] similarity in sets of regulated transcripts, and show [r] correlation in regulated gene expression, which is [substantially / somewhat / not at all] stronger than at forgetting. Overall, our results suggest that forgetting represents [decay / retrieval-failure / mixed mechanisms].


Sign in / Sign up

Export Citation Format

Share Document