scholarly journals N-cadherin mediated cell contact inhibits germinal vesicle breakdown in mouse oocytes maintained in vitro

Reproduction ◽  
2006 ◽  
Vol 131 (3) ◽  
pp. 429-437 ◽  
Author(s):  
J J Peluso

The effect of granulosa cell contact on the ability of zona-free oocytes to undergo germinal vesicle breakdown (GVBD) was assessed using a granulosa cell co-culture system. Oocytes contacted granulosa cells in a site-specific manner such that their GV was away from the granulosa cells. Also contact with granulosa cells reduced the percentage of oocytes undergoing GVBD from about 40% to 15%. GVBD was inhibited by contact with granulosa cells but not a granulosa cell-secreted product, since oocytes cultured in the same culture, that were adjacent to the granulosa cell monolayer underwent GVBD at the same rate as controls. Similarly, media collected from granulosa cell cultures did not attenuate the rate of GVBD. The ability of granulosa cell contact to inhibit GVBD was equal to that of db-cAMP. Moreover, the ability of granulosa cells to inhibit GVBD was not mimicked by spontaneously immortalized granulosa cells. This cell specificity appeared to be related to N-cadherin, since granulosa cells and oocytes express N-cadherin and a N-cadherin antibody attenuates the effect of granulosa cell contact. The mechanism through which N-cadherin mediated cell contact maintains meiotic arrest is unknown. It is possible that homophilic N-cadherin binding between the granulosa cells and oocyte acts through a junxtacrine mechanism, which in part may lead in the activation fibroblast growth factor (FGF) receptors that are expressed by the oocyte. The involvement of FGF receptors is supported by the observations that FGF and a N-cadherin peptide known to activate FGF receptors inhibit GVBD.

Zygote ◽  
2005 ◽  
Vol 13 (4) ◽  
pp. 303-308 ◽  
Author(s):  
H. Iwata ◽  
T. Hayashi ◽  
H. Sato ◽  
K. Kimura ◽  
T. Kuwayama ◽  
...  

During ovary storage oocytes lose some of their developmental competence. In the present study, we maintained storage solutions of phosphate-buffered saline (PBS) at various temperatures (20 or 35 °C) or supplemented them with magnesium (Mg), raffinose and sucrose. Subsequently, we examined the kinetics of electrolytes in the follicular fluid (FF) during the ovary storage period (9h), the survival rate of granulosa cells in the follicles, and the developmental competence of oocytes after the storage. Lowering the temperature from 35 to 20 °C increased the total cell number of blastocysts that developed at 7 days after in vitro maturation and in vitro fertilization of oocytes. In stock solution with supplements of 15 mM Mg or a combination of 5 mM Mg and 10 mM raffinose or sucrose, a significantly higher number of oocytes developed into blastocysts with a large number of cells in each blastocyst, and a significantly higher number of living granulosa cells were obtained as compared with stock solutions without any supplements. During ovary storage, the concentrations of potassium and chloride in the FF were increased, and the addition of Mg to the stock solution increased the concentration of Mg in the FF. Germinal vesicle breakdown in oocytes that were collected from ovaries stored in the solution supplemented with 15 mM Mg or a combination of 5 mM Mg and 10 mM of raffinose occurred at a slower rate than that in oocytes collected from ovaries stored in PBS alone. On the other hand, the oocytes collected from ovaries stored in the solution supplemented with 15 mM Mg or a combination of 5 mM Mg and 10 mM raffinose reached the metaphase II (MII) stage more rapidly than the oocytes collected from ovaries stored in the PBS alone. In conclusion, the modification of stock solution by the addition of Mg and raffinose improved the developmental competence of oocytes obtained from ovaries preserved for a long period.


Reproduction ◽  
2009 ◽  
Vol 138 (2) ◽  
pp. 235-246 ◽  
Author(s):  
Svetlana Uzbekova ◽  
Mohamad Salhab ◽  
Christine Perreau ◽  
Pascal Mermillod ◽  
Joëlle Dupont

Glycogen synthase kinase 3 (GSK3) regulates cellular metabolism and cell cycle via different signalling pathways. In response to insulin and growth factors GSK3 is serine-phosphorylated and inactivated. We analysed GSK3B expression and activation in bovine cumulus cells (CC) and oocytes at different meiotic stagesin vitroin parallel with MAP kinases ERK (MAPK3/MAPK1) and p38 (MAPK14). GSK3B localised to cytoplasm in granulosa cells and in oocytes throughout folliculogenesis. In mature metaphase-II (MII) oocytes, GSK3B was concentrated to the region of midzone between the oocyte and the first polar body, as well as active phospho-Thr Aurora A kinase (AURKA). Duringin vitromaturation (IVM), in oocytes, phospho-Ser9-GSK3B level increased as well as phospho-MAPK3/MAPK1, while phospho-MAPK14 decreased. In CC, phospho-MAPK14 increased upon germinal vesicle breakdown (GVBD)/metaphase-I (MI) and then decreased during transition to MII. Administration of inhibitors of GSK3 activity (lithium chloride or 2′Z,3′E -6-bromoindirubin-3′-oxime) rapidly increased phospho-Ser9-GSK3B, and led to transient decrease of phospho-MAPK3/MAPK1 and to durable enhancing of phospho-MAPK14 in granulosa primary cell culture. GSK3 inhibitors during IVM diminished cumulus expansion and delayed meiotic progression. In cumulus, phospho-MAPK14 level was significantly higher in the presence of inhibitors, comparing with control, through the time of MI/MII transition. In oocytes, phospho-GSK3B was increased and phospho-MAPK3/MAPK1 was decreased before GVBD and oocytes were mainly arrested at MI. Therefore, GSK3B might regulate oocyte meiosis, notably MI/MII transition being the part of MAPK3/1 and MAPK14 pathways in oocytes and CC. GSK3B might be also involved in the local activation of AURKA that controls this transition.


Reproduction ◽  
2000 ◽  
pp. 275-281 ◽  
Author(s):  
KM Kirkup ◽  
AM Mallin ◽  
CA Bagnell

Epithelial cadherin (E-cadherin) is a member of the cadherin family of calcium-dependent cell adhesion molecules and is present in the ovary. Although expression of E-cadherin is high in healthy pig granulosa cells and low in granulosa cells of atretic follicles, the importance of E-cadherin-mediated adhesion in granulosa cell function is unclear. The aim of the present study was to determine the impact of immunoneutralization of E-cadherin on granulosa cell adhesion, DNA synthesis and cell proliferation in vitro. Before attachment, pig granulosa cells were exposed to a monoclonal E-cadherin antibody (DECMA-1) which blocks E-cadherin function. Controls included substitution of the antibody with either mouse ascites fluid or another E-cadherin antibody directed against the cytoplasmic domain and which was therefore inaccessible in intact cells. Both granulosa cell proliferation and insulin-like growth factor I-induced DNA synthesis were inhibited significantly in the presence of DECMA-1 compared with controls (P < 0.05). Control granulosa cells in culture formed large clusters with many cells packed tightly together. However, after 48 h exposure to the function-perturbing E-cadherin antibody, there was a significant decrease in the size of the granulosa cell clusters (P < 0.05) and the degree of cell-cell contact was reduced compared with control cultures. No effects on DNA synthesis, cell proliferation or cell adhesion were observed when DECMA-1 was substituted with either mouse ascites fluid or the antibody specific for the cytoplasmic domain of E-cadherin. In conclusion, these data provide evidence to support the hypothesis that E-cadherin is important for maintaining granulosa cell contact, DNA synthesis and cell proliferation in vitro. These results indicate that E-cadherin plays a fundamental role in maintaining both the structure and function of ovarian follicles.


Author(s):  
Sarah Beschta ◽  
Katja Eubler ◽  
Nancy Bohne ◽  
Ignasi Forne ◽  
Dieter Berg ◽  
...  

AbstractHuman primary granulosa cells (GCs) derived from women undergoing oocyte retrieval can be cultured and used as a cellular model for the study of human ovarian function. In vitro, they change rapidly, initially resembling cells of the preovulatory follicle and then cells of the corpus luteum. They are derived from individual patients, whose different medical history, lifestyle and age lead to heterogeneity. Thus, cells can rarely be ideally matched for cellular experiments or, if available, only in small quantities. We reasoned that cryopreservation of human GCs may be helpful to improve this situation. Previous studies indicated the feasibility of such an approach, but low survival of human GCs was reported, and effects on human GC functionality were only partially evaluated. We tested a slow freezing protocol (employing FCS and DMSO) for human GCs upon isolation from follicular fluid. We compared cryopreserved and subsequently thawed cells with fresh, non-cryopreserved cells from the same patients. About 80% of human GCs survived freezing/thawing. No differences were found in cell morphology, survival rate in culture, or transcript levels of mitochondrial (COX4, OPA1, TOMM20), steroidogenic (CYP11A1, CYP19A1) or cell–cell contact genes (GJA1) between the two groups in cells cultured for 1–5 days. A proteomic analysis revealed no statistically significant change in the abundance of a total of 5962 proteins. The two groups produced comparable basal levels of progesterone and responded similarly to hCG with elevation of progesterone. Taken together, our results show this to be a rapid and readily available method for the cryopreservation of human GCs. We anticipate that it will allow future large-scale experiments and may thereby improve cellular studies with human ovarian cells.


Reproduction ◽  
2010 ◽  
Vol 140 (2) ◽  
pp. 295-303 ◽  
Author(s):  
Jennifer L Juengel ◽  
Lisa J Haydon ◽  
Brigitta Mester ◽  
Brian P Thomson ◽  
Michael Beaumont ◽  
...  

IGFs are known to be key regulators of ovarian follicular growth in eutherian mammals, but little is known regarding their role in marsupials. To better understand the potential role of IGFs in the regulation of follicular growth in marsupials, expression of mRNAs encoding IGF1, IGF2, IGF1R, IGF-binding protein 2 (IGFBP2), IGFBP4 and IGFBP5 was localized by in situ hybridization in developing ovarian follicles of the brushtail possum. In addition, the effects of IGF1 and IGF2 on granulosa cell function were tested in vitro. Both granulosa and theca cells synthesize IGF mRNAs, with the theca expressing IGF1 mRNA and granulosa cell expressing IGF2 mRNA. Oocytes and granulosa cells express IGF1R. Granulosa and theca cells expressed IGFBP mRNAs, although the pattern of expression differed between the BPs. IGFBP5 mRNA was differentially expressed as the follicles developed with granulosa cells of antral follicles no longer expressing IGFBP5 mRNA, suggesting an increased IGF bioavailability in the antral follicle. The IGFBP protease, PAPPA mRNA, was also expressed in granulosa cells of growing follicles. Both IGF1 and IGF2 stimulated thymidine incorporation but had no effect on progesterone production. Thus, IGF may be an important regulator of ovarian follicular development in marsupials as has been shown in eutherian mammals.


1992 ◽  
Vol 12 (7) ◽  
pp. 3192-3203 ◽  
Author(s):  
K M Pickham ◽  
A N Meyer ◽  
J Li ◽  
D J Donoghue

The p34cdc2 protein kinase is a component of maturation-promoting factor, the master regulator of the cell cycle in all eukaryotes. The activity of p34cdc2 is itself tightly regulated by phosphorylation and dephosphorylation. Predicted regulatory phosphorylation sites of Xenopus p34cdc2 were mutated in vitro, and in vitro-transcribed RNAs were injected into Xenopus oocytes. The cdc2 single mutants Thr-14----Ala and Tyr-15----Phe did not induce germinal vesicle breakdown (BVBD) upon microinjection into oocytes. In contrast, the cdc2 double mutant Ala-14/Phe-15 did induce GVBD. Both the Ala-14 and Ala-14/Phe-15p34cdc2 mutants were shown to coimmunoprecipitate cyclin B1 and to phosphorylate histone H1 in immune complex kinase assays. Microinjection of antisense oligonucleotides to c-mosXe was used to demonstrate the role of mos protein synthesis in the induction of GVBD by the Ala-14/Phe-15 cdc2 mutant. Thr-161 was also mutated. p34cdc2 single mutants Ala-161 and Glu-161 and triple mutants Ala-14/Phe-15/Ala-161 and Ala-14/Phe-15/Glu-161 failed to induce GVBD in oocytes and showed a decreased binding to cyclin B1 in coimmunoprecipitations. Each of the cdc2 mutants was also assayed by coinjection with cyclin B1 or c-mosXe RNA into oocytes. Several of the cdc2 mutants were found to affect the kinetics of cyclin B1 and/or mos-induced GVBD upon coinjection, although none affected the rate of progesterone-induced maturation. We demonstrate here the significance of Thr-14, Tyr-15, and Thr-161 of p34cdc2 in Xenopus oocyte maturation. In addition, these results suggest a regulatory role for mosXe in induction of oocyte maturation by the cdc2 mutant Ala-14/Phe-15.


Reproduction ◽  
2014 ◽  
Vol 147 (1) ◽  
pp. 73-80 ◽  
Author(s):  
JongYeob Choi ◽  
MinWha Jo ◽  
EunYoung Lee ◽  
DooSeok Choi

In this study, we examined whether granulosa cell autophagy during follicular development and atresia was regulated by the class I phosphoinositide-3 kinase/protein kinase B (AKT) pathway, which is known to control the activity of mammalian target of rapamycin (mTOR), a major negative regulator of autophagy. Ovaries and granulosa cells were obtained using an established gonadotropin-primed immature rat model that induces follicular development and atresia. Autophagy was evaluated by measuring the expression level of microtubule-associated protein light chain 3-II (LC3-II) using western blots and immunohistochemistry. The activity of AKT and mTOR was also examined by observing the phosphorylation of AKT and ribosomal protein S6 kinase (S6K) respectively. After gonadotropin injection, LC3-II expression was suppressed and phosphorylation of AKT and S6K increased in rat granulosa cells. By contrast, gonadotropin withdrawal by metabolic clearance promoted LC3-II expression and decreased phosphorylation of AKT and S6K. In addition,in-vitroFSH treatment of rat granulosa cells also indicated inhibition of LC3-II expression accompanied by a marked increase in phosphorylation of AKT and S6K. Inhibition of AKT phosphorylation using AKT inhibitor VIII suppressed FSH-mediated phosphorylation of S6K, followed by an increase in LC3-II expression. Furthermore, co-treatment with FSH and AKT inhibitor increased the levels of apoptosis and cell death of granulosa cells compared with the single treatment with FSH. Taken together, our findings indicated that AKT-mediated activation of mTOR suppresses granulosa cell autophagy during follicular development and is involved in the regulation of apoptotic cell death.


2017 ◽  
Vol 234 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Li Zhang ◽  
XiaoXin Zhang ◽  
Xuejing Zhang ◽  
Yu Lu ◽  
Lei Li ◽  
...  

MicroRNAs (MiRNAs) play important regulatory roles in many cellular processes. MiR-143 is highly enriched in the mouse ovary, but its roles and underlying mechanisms are not well understood. In the current study, we show that miR-143 is located in granulosa cells of primary, secondary and antral follicles. To explore the specific functions of miR-143, we transfected miR-143 inhibitor into primary cultured granulosa cells to study the loss of function of miR-143 and the results showed that miR-143 silencing significantly increased estradiol production and steroidogenesis-related gene expression. Moreover, our in vivo and in vitro studies showed that follicular stimulating hormone (FSH) significantly decreased miR-143 expression. This function of miR-143 is accomplished by its binding to the 3’-UTR of KRAS mRNA. Furthermore, our results demonstrated that miR-143 acts as a negative regulating molecule mediating the signaling pathway of FSH and affecting estradiol production by targeting KRAS. MiR-143 also negatively acts in regulating granulosa cells proliferation and cell cycle-related genes expression. These findings indicate that miR-143 plays vital roles in FSH-induced estradiol production and granulosa cell proliferation, providing a novel mechanism that involves miRNA in regulating granulosa cell functions.


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