Cumulus cells accelerate aging of mouse oocytes by secreting a soluble factor(s)

The high level of cyclic adenosine monophosphate (cAMP), which is provided to the oocytes from cumulus cells via gap junctional complexes in cumulus-enclosed oocytes (CEOs), is known to contribute to meiotic arrest at the germinal vesicle (GV) stage of CEOs. However, whether intraoocyte cAMP during the period of in vitro maturation (IVM) affects postfertilization developmental competence of mouse oocytes still remains unclear. The aim of this study was to examine the effects of FSH or dibutyryl cAMP (dbcAMP) treatment during IVM on in vitro development of mouse oocytes after in vitro fertilization (IVF). Whether a junctional association between cumulus cells and the oocyte would be essential for a cytoplasmic maturation-promoting effect was also examined. CEOs were isolated from and eCG-primed 3-week-old ICR mouse by rupturing preovulatory follicles with needles in M16 medium with 5% FCS and essential and nonessential amino acids (basal medium). IVM media used were basal medium without (control) or with 100 µm dbcAMP or 1 IU mL–1 FSH. Carbenoxolone (100 µm, CBX), an inhibitor of gap junction, was used to inhibit a junctional association between cumulus cells and the oocyte. Denuded oocytes (DOs) were prepared by repeatedly pipetting in basal medium with 0.2% hyaluronidase. CEOs and DOs were cultured in IVM media at 37�C under 5% CO2 in air for 16.5 h, and then transferred to TYH medium (a modified Krebs-Ringer bicarbonate medium) containing 0.4% BSA, followed by insemination with capacitated sperm. After 6 h of IVF, inseminated oocytes were cultured in KSOM medium with 0.3% BSA. Development to the 2-cell and blastocyst stages was estimated at 24 h and 120 h after IVF, respectively. All experiments were done in 3 replicates, and the statistical analysis was carried out by ANOVA and Fisher's protected least-squares difference (PLSD) test. When CEOs were matured in IVM media, the rates of postfertilization development to the 2-cell and blastocyst stages of oocytes matured in the control medium were very low(29% and 13%, respectively), whereas those of oocytes matured with FSH or dbcAMP significantly increased (FSH: 61% and 52%, dbcAMP: 63 and 57%, respectively, v. control; P < 0.05). Next, when CEOs were matured in basal medium with 1 IU mL–1 FSH and 100 µm CBX, the developmental rate to the 2-cell stage (56%) was similar to that in medium with FSH alone (61%) but the rate to the blastocyst stage (40%) was little lower compared with that in medium with FSH alone (52%), although not significantly different (P > 0.05). Furthermore, when DOs were matured in IVM media, the developmental rates to the blastocyst stage after IVF of the oocytes matured with FSH or dbcAMP significantly increased (FSH: 25%, dbcAMP: 15%; P < 0.05) compared with those in control medium (7%). Taken together, it is suggested that increasing the concentration of intraoocyte cAMP during the IVM period is important to improve the developmental competence after IVF of mouse oocytes, and that the competence is acquired in part in a cumulus-oocyte junctional communication-independent manner.

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IVM of mouse fully grown germinal vesicle oocytes upon a feeder layer of selected cumulus cells enhances their developmental competence

Reproduction Fertility and Development ◽

10.1071/rd18444 ◽

2019 ◽

Vol 31 (6) ◽

pp. 1068

Author(s):

Federica Cavalera ◽

Milena Simovic ◽

Mario Zanoni ◽

Valeria Merico ◽

Silvia Garagna ◽

...

Keyword(s):

Germinal Vesicle ◽

Cumulus Cells ◽

Development Rate ◽

Developmental Competence ◽

Blastocyst Development ◽

Oocyte Developmental Competence ◽

Mouse Oocytes ◽

Feeder Layers ◽

Morula Stage ◽

Bidirectional Exchange

In the ovary, acquisition of oocyte developmental competence depends on a bidirectional exchange between the gamete and its companion cumulus cells (CCs). In this study we investigated the contribution of CCs surrounding oocytes of known developmental competence or incompetence to the acquisition of oocyte developmental competence. To this end, feeder layers of CCs (FL-CCs) were prepared using CCs isolated either from: (1) developmentally competent mouse oocytes whose nucleolus was surrounded by a chromatin ring (FL-SN-CCs); or (2) developmentally incompetent mouse oocytes whose nucleolus was not surrounded by a chromatin ring (FL-NSN-CCs). Denuded, fully grown oocytes (DOs) were matured to the MII stage on either FL-SN-CCs or FL-NSN-CCs, inseminated with spermatozoa and cultured throughout preimplantation development. FL-SN-CCs significantly improved the acquisition of oocyte developmental competence, with a blastocyst development rate equal to that for maturation of intact cumulus–oocyte–complexes. In contrast, DOs matured on FL-NSN-CCs or in the absence of CCs exhibited developmental failure, with embryos arresting at either the 4-cell or morula stage. These results set a culture platform to further improve the protocols for the maturation of DOs and to unravel the molecules involved in the cross-talk between the gamete and its companion CCs during the germinal vesicle to MII transition.

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Metabolic markers of developmental competence for in vitro-matured mouse oocytes

Reproduction ◽

10.1530/rep.1.00831 ◽

2005 ◽

Vol 130 (4) ◽

pp. 475-483 ◽

Cited By ~ 31

Author(s):

Kimberly A Preis ◽

George Seidel ◽

David K Gardner

Keyword(s):

Lactate Production ◽

Glucose Consumption ◽

Cumulus Cells ◽

Defined Medium ◽

Developmental Competence ◽

Metabolic Markers ◽

Oocyte Competence ◽

Carbohydrate Consumption ◽

Mouse Oocytes

In vitro maturation of oocytes has enormous potential in assisted reproductive technology, but its use has been limited due to insufficient knowledge of oocyte physiology during this dynamic period and lack of an adequate maturation system. The aim of this study was to characterize the metabolic profiles of three groups of oocytes throughout maturation: cumulus–oocyte complexes (COCs), denuded oocytes, and denuded oocytes co-cultured with cumulus cells. Mouse oocytes were collected from 28-day-old unstimulated females and matured in a defined medium. Oocytes were matured individually and transferred into fresh 0.5 μl drops of medium at 4 h intervals until 16 h. Ultramicrofluorimetry was used to quantitate carbohydrate consumption from and metabolite release into the medium. Glucose consumption and lactate production of COCs increased (P < 0.001) over the maturation interval (0–16 h). Glucose consumption by COCs that subsequently fertilized was higher between 8–12 h of maturation than by COCs that did not fertilize (38 versus 29 pmol/COC per h, respectively; P < 0.01). Lactate production by COCs that subsequently fertilized was higher between 8–16 h of maturation, than by oocytes that did not fertilize (8–12 h, 66 versus 46 pmol/COC per h, P < 0.01; 12–16 h, 56 versus 40 pmol/COC per h, respectively; P < 0.05). These data indicate that the final hours of maturation may hold a unique marker of oocyte competence, as during this time fertilizable COCs take up more glucose and produce more lactate than those not subsequently fertilized.

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Nitric oxide produced by cumulus cells stimulates maturation of mouse oocytes

Chinese Science Bulletin ◽

10.1360/03tb9015 ◽

2003 ◽

Vol 48 (1) ◽

pp. 72 ◽

Cited By ~ 1

Author(s):

Shumin BU

Keyword(s):

Nitric Oxide ◽

Cumulus Cells ◽

Mouse Oocytes

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Obox4-silencing-activated STAT3 and MPF/MAPK signaling accelerate nuclear membrane breakdown in mouse oocytes

Reproduction ◽

10.1530/rep-15-0020 ◽

2016 ◽

Vol 151 (4) ◽

pp. 369-378 ◽

Cited By ~ 7

Author(s):

Hyun-Seo Lee ◽

Kyeoung-Hwa Kim ◽

Eun-Young Kim ◽

Su-Yeon Lee ◽

Jung-Jae Ko ◽

...

Keyword(s):

Nuclear Membrane ◽

Molecular Mechanisms ◽

Germinal Vesicle ◽

Cumulus Cells ◽

Mapk Signaling ◽

Interferon Α ◽

Membrane Breakdown ◽

Nuclear Maturation ◽

Mouse Oocytes

Mouse oocytes begin to maturein vitroonce liberated from ovarian follicles. Previously, we showed that oocyte-specific homeobox 4 (Obox4) is critical for maintaining the intact nuclear membrane of the germinal vesicle (GV) in oocytes and for completing meiosis at the metaphase I–II (MI–MII) transition. This study further examines the molecular mechanisms of OBOX4 in regulating GV nuclear membrane breakdown. Maturation-promoting factor (MPF) and MAPK are normally inactive in GV stage oocytes but were activated prematurely in arrested GV stage oocytes by 3-isobutyl-1-metyl-xanthine (IBMX)in vitroafterObox4RNA interference (RNAi). Furthermore, signal transducer and activator of transcription 3 (STAT3) was significantly activated byObox4RNAi. We confirmed that thisObox4RNAi-induced premature STAT3 and MPF/MAPK activation at the GV stage provoked subsequent GV breakdown (GVBD) despite the opposing force of high cAMP in the IBMX-supplemented medium to maintain intact GV. When cumulus–oocyte complexes were exposed to interferon α (IFNA), a STAT3 activator, oocytes matured and cumulus cells expanded to resume nuclear maturation in IBMX-supplemented medium, suggesting that STAT3 activation is sufficient for stimulating the continuation of meiosis. Using Stattic, a specific STAT3 inhibitor, we confirmed that GVBD involves STAT3 activation inObox4-silenced oocytes. Based on these findings, we concluded that i)Obox4is an important upstream regulator of MPF/MAPK and STAT3 signaling, and ii)Obox4is a key regulator of the GV arrest mechanism in oocytes.

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The effect of PD98059 on MAPK regulation in cumulus-enclosed and cumulus-free mouse oocytes

Zygote ◽

10.1017/s0967199403001084 ◽

2003 ◽

Vol 11 (1) ◽

pp. 61-68 ◽

Cited By ~ 6

Author(s):

Jaroslav Kalous ◽

Michal Kubelka ◽

Jan Motlík

Keyword(s):

Germinal Vesicle ◽

Cumulus Cells ◽

Experimental Conditions ◽

Germinal Vesicle Breakdown ◽

Mapk Activation ◽

Mapk Phosphorylation ◽

Kinase Activation ◽

Mouse Oocytes ◽

Significant Difference ◽

Epidermal Growth

The effect of the p42/44 mitogen-activated kinase (MAPK) inhibitor, PD98059, on MAPK activation and meiosis resumption in mouse oocytes was studied. When germinal vesicle (GV)-stage denuded oocytes (DOs) were cultured continuously in 50 μM PD98059, germinal vesicle breakdown (GVBD) was postponed for 2-3 h. MAPK phosphorylation and activation was delayed as well. However, PD98059 did not impair histone H1 kinase activation. After 14 h of culture there was no significant difference in the rate of DOs reaching metaphase II (MII) arrest in either control or experimental conditions. The effect of PD98059 on MAPK inhibition was further tested in epidermal growth factor (EGF)-treated oocyte–cumulus complexes (OCCs). Exposure of GV-stage OCCs for 5 min to EGF (10 ng/ml) induced a considerable increase in MAPK phosphorylation. After OCCs were further cultured in 50 μM PD98059 a rapid dephosphorylation of MAPK was induced. Already after 1 min of treatment the non-phosphorylated form of MAPK dominated, indicating the high effectivity of PD98059. This result indicates that short EGF/PD98059 treatment of OCCs induced MAPK phosphorylation/dephosphorylation in cumulus cells only. As only a transient delay in MAPK phosphorylation and activation was observed in PD98059-treated DOs we conclude that there is also another PD98059-nonsensitive pathway(s) leading to MAPK activation in mouse oocytes. The data obtained suggest that meiosis resumption in mouse oocytes is somehow influenced by the MEK/MAPK activation pathway.

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MOUSE OOCYTES PROMOTE STEROL BIOSYNTHESIS IN CUMULUS CELLS: MORE EVIDENCE FOR OOCYTEREGULATION OF METABOLIC COOPERATIVITY BETWEEN GRANULOSA CELLS AND OOCYTES

Biology of Reproduction ◽

10.1093/biolreprod/77.s1.189c ◽

2007 ◽

Vol 77 (Suppl_1) ◽

pp. 189-189

Author(s):

You-Qiang Su ◽

Koji Sugiura ◽

Karen Wigglesworth ◽

Stephanie Pangas ◽

Martin Matzuk ◽

...

Keyword(s):

Granulosa Cells ◽

Cumulus Cells ◽

Sterol Biosynthesis ◽

Mouse Oocytes

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Pyruvate prevents aging of mouse oocytes

Reproduction ◽

10.1530/rep-09-0122 ◽

2009 ◽

Vol 138 (2) ◽

pp. 223-234 ◽

Cited By ~ 26

Author(s):

Na Liu ◽

Yan-Guang Wu ◽

Guo-Cheng Lan ◽

Hong-Shu Sui ◽

Li Ge ◽

...

Keyword(s):

Histone Acetylation ◽

Culture Medium ◽

Accelerated Aging ◽

Cumulus Cells ◽

Underlying Mechanism ◽

Cortical Granules ◽

Developmental Potential ◽

Assisted Reproduction Techniques ◽

Mouse Oocytes ◽

Oocyte Aging

Inhibiting oocyte aging is important not only for healthy reproduction but also for the success of assisted reproduction techniques. Although our previous studies showed that cumulus cells accelerated aging of mouse oocytes, the underlying mechanism is unknown. The objective of this paper was to study the effects of pyruvate and cumulus cells on mouse oocyte aging. Freshly ovulated mouse cumulus–oocyte complexes (COCs) or cumulus-denuded oocytes (DOs) were cultured in Chatot-Ziomek-Bavister (CZB) medium or COC-conditioned CZB medium supplemented with different concentrations of pyruvate before being examined for aging signs and developmental potential. Pyruvate supplementation to CZB medium decreased rates of ethanol-induced activation in both COCs and DOs by maintaining their maturation-promoting factor activities, but more pyruvate was needed for COCs than for DOs. Addition of pyruvate to the COC-conditioned CZB also alleviated aging of DOs. Observations on cortical granules, level of BCL2 proteins, histone acetylation, intracellular concentration of glutathione, and embryo development all confirmed that pyruvate supplementation inhibited aging of mouse oocytes. It is concluded that the aging of mouse oocytes, facilitated by culture in COCs, can be partially prevented by the addition of pyruvate to the culture medium.

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