Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Cumulus Cells”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed2002

Steroidogenesis in cumulus cells of bovine cumulus-oocyte-complexes matured in vitro with BSA and different concentrations of steroids.

The present in vitro experiments were designed to evaluate the ability of bovine cumulus-oocyte-complexes (COCs) to produce steroids and also to evaluate the modulatory effects of added estradiol, progesterone and testosterone on the steroidogenic activity of COCs. Considerable estradiol accumulation was observed in the control maturation medium for in vitro maturation of bovine COCs during the 24h of maturation (P<0.05). When testosterone was added to the medium at various concentrations, a slight estradiol accumulation occurred, which, however, was lower (P<0.05) than that observed in the control medium. Slight estradiol accumulation was observed in maturation medium containing progesterone at concentrations of 2.5, 5.0 and 10.0 microg/ml, but these increases were less (P<0.05) than those observed in the control medium. However, in the presence of 1.0 microg/ml progesterone, estradiol accumulation was equal to that of the control medium (P>0.05). Progesterone accumulation (P<0.05) was observed in the control medium for in vitro maturation of bovine COCs. When estradiol was added to the maturation medium, progesterone accumulation was observed, but was significant (P<0.05) only when the medium was supplemented with the lesser concentrations of estradiol utilized in the experiment (1.0 microg/ml). The results demonstrated that (1) cumulus cells of bovine COCs are able to secrete estradiol and progesterone in culture systems for in vitro maturation, and this steroidogenesis is modulated by the steroids progesterone, testosterone and estradiol, and (2) the addition of estradiol to the in vitro maturation medium of bovine oocytes should be reviewed, since cumulus cells of COCs have been demonstrated to secrete estradiol in the maturation medium.

Animals↗
PubMed1992

Development of in vitro fertilized oocytes from pregnant and nonpregnant cows in oviductal epithelial and cumulus cell co-culture systems.

The objectives of this study were 1) to measure cleavage, blastocyst formation, and blastocyst hatching after in vitro maturation (IVM), fertilization (IVF) and culture (IVC) of oocytes aspirated from pregnant versus nonpregnant cows, and 2) to compare embryo development in co-culture with bovine oviductal epithelial cells versus cumulus cells. No differences in cleavage (38 versus 40%), blastocyst formation (13 versus 13%), or blastocyst hatching (53 versus 51%) were observed for in vitro-matured, fertilized, and cultured oocytes from pregnant versus nonpregnant cows, respectively (P>0.05), indicating that nonpregnant and early-pregnant cows are equally acceptable donors of oocytes for IVM/IVF/IVC procedures. Cleavage (36 versus 40%), blastocyst formation (11 versus 12%), and blastocyst hatching (50 versus 55%) were not different for embryos co-cultured with oviductal epithelial cells versus cumulus cells (P>0.05). Thus, equivalent embryo development can be obtained with co-culture systems commonly used for in vitro-derived bovine embryos. These results help to define variables that affect comparison of results across laboratories and that are relevant to the practical application of IVM/IVF/IVC procedures to cattle.

Journal Article↗
PubMed1992

Human granulosa-luteal and cumulus cells express transforming growth factors-beta type 1 and type 2 mRNA.

Human granulosa-luteal cells and cumulus cells obtained from women undergoing in vitro fertilization and embryo transfer (IVF-ET) were examined for the presence of TGF-beta 1 and TGF-beta 2 mRNA by reverse transcription-polymerase chain reaction (RT-PCR) analysis. RT-PCR analysis revealed that both follicle cell types express mRNA for both TGF-beta subtypes. Verification of RT-PCR products was done by restriction enzyme digestion analysis. These results suggest a role(s) for TGF-beta 1 and TGF-beta 2 in the development of human granulosa-luteal cells and the oocyte-cumulus cell complex.

Base Sequence↗
PubMed1999

Identification of link protein during follicle development and cumulus cell cultures in rats.

Cumulus oocyte complex (COC) expansion is induced through hyaluronic acid production and accumulation of proteins of the inter-alpha-trypsin inhibitor family in the gonadotropin-stimulated cumulus cells. Link protein, a glycoprotein found in cartilage, interacts specifically with hyaluronic acid and stabilizes the binding of proteoglycan monomers to hyaluronic acid to form aggregates. The aim of this study was to investigate the expression of immunoreactive link protein during follicle development in rats and in cumulus cells in culture by immunohistochemistry and Western blot as well as by specific enzyme-linked immunosorbent assay. Immunohistochemical analysis revealed that the extracellular matrix of cumulus cells that were morphologically at a stage of COC expansion were markedly stained for link protein, whereas granulosa cells from immature follicles were not stained. Cumulus cells deposited link protein into the extracellular matrix in an in vitro culture system. The staining intensity was negated by the treatment with hyaluronidase, suggesting that the link protein is bound to hyaluronic acid. We have identified a 42-kDa immunoreactive link protein in rat ovary during the preovulatory period and in COC extracts. Addition of FSH to the medium of cumulus cells in culture supplemented with 10% FBS and oocyte-conditioned medium resulted in an increased rate of link protein synthesis. This work suggests that the cumulus cells synthesize the link protein that may stabilize the binding of inter-alpha-trypsin inhibitor or dermatan sulfate proteoglycan to hyaluronic acid to make up hyaluronic acid-rich matrix aggregate.

Animals↗
PubMed1986

Late preovulatory synthesis of proteoglycans by the human oocyte and cumulus cells and their secretion into the oocyte-cumulus-complex extracellular matrices.

Light- and electron-microscope autoradiography using 3H-glucosamine and 3H-fucose as precursors was employed to investigate proteoglycan synthesis and secretion by late preovulatory human oocytes and cumulus cells. Both the oocyte and cumulus cells were found to be important cellular sources supplying proteoglycans to the oocyte-cumulus-complex extracellular matrices, i.e., the zona pellucida and the cumulus intercellular matrix. Both the oocyte and cumulus cells were shown to secrete labelled proteoglycans into the zona pellucida. Labelled proteoglycans were also detected in the cumulus intercellular matrix. Chase experiments revealed the labelled molecules to be relatively closely associated with both the zona pellucida and the cumulus intercellular matrix. Staining with chromic acid and phosphotungstic acid showed proteoglycan material to penetrate from the cumulus intercellular matrix into pores of the zona pellucida. This material is thought to be a structural equivalent of the newly synthesized proteoglycans secreted by cumulus cells and migrating into the zona pellucida (as detected by autoradiography). It is concluded that newly synthesized proteoglycans secreted by the oocyte and cumulus cells in the late preovulatory period are a component of the microenvironment in which fertilization takes place.

Autoradiography↗
PubMed1993

Functional differentiation in progesterone secretion by granulosa versus cumulus cells in the human preovulatory follicle and the effect of different induction of ovulation protocols.

OBJECTIVE: To investigate P secretion by granulosa cells (GCs) versus cumulus cells derived from human preovulatory follicles. DESIGN: Cells were recovered by aspiration of preovulatory follicles in 44 women participating in an IVF program. Induction of ovulation was performed using clomiphene citrate, hMG and hCG (group I), hMG/hCG (group II), buserelin acetate/hMG/hCG (group III), or Decapeptyl/hMG/hCG (group IV). SETTING: Laboratories of the IVF Unit at the Department of Obstetrics and Gynecology, Carmel Medical Center, Haifa, Israel. MAIN OUTCOME MEASURES: Secretion of P was examined after cultures for 96 hours under nonstimulated and hCG stimulated conditions. RESULTS: Progesterone secretion by GCs derived from all four groups was found to be higher compared with the respective cumulus cells. However, although the ratios of P secretion by GCs versus cumulus cells in groups I, II, and III were very similar, a significantly lower value was observed in group IV. The response of GCs to hCG in terms of P secretion was higher with at least one dose of hCG in groups I and IV compared with groups II and III. The response of cumulus cells to hCG was absent regardless of the treatment protocol used in vivo. CONCLUSION: Our results demonstrate that in the human preovulatory follicle, GCs and cumulus cells differ in their capacity to secrete P as well as in their response to hCG. They further suggest that the mode of induction of ovulation affects the relative capacity of GCs and cumulus cells to secrete P and their ability to respond to hCG.

Adult↗
PubMed1991

Influence of dbcAMP on the inhibitory effect of cumulus cell factor(s).

The factor(s) produced by porcine cumulus cells (cumulus cell factor (s): CCF) was described as quantitatively inhibiting the maturation of oocytes in vitro (Petr et al, 1989). When 1, 10, 20 or 40 cumulus oocyte complexes (COCs) were cultured in a droplet of medium (vol 10 microliters), germinal vesicle breakdown (GVBD) was observed in 85, 78, 57 or 19% of the oocytes, respectively. GVBD was observed in 82, 84, 80 or 90% of cumulus-free oocytes, respectively, when they were cultured at the same numbers per 10-microliters droplet. When 1, 10, 20 or 40 cumulus-free oocytes were cultured under the same conditions in a medium containing 140 dbcAMP per ml, 61, 63, 60 or 58% of them were observed at GVBD. However, when COCs were cultured in a 10 microliter droplet of medium with 140 micrograms of dbcAMP per ml, GVBD occurred in 64, 42, 9 or 0% respectively. Based on these results, we can conclude that dbcAMP exerted a further inhibitory effect on GVBD in pig oocytes cultured under the influence of inhibitory factor(s) from cumulus cells. On the other hand, dbcAMP was shown to partly overcome the effect of CCF on GVBD in porcine oocytes. This suggestion was based on the finding that a 6-h pre-culture of COCs in a medium with 1,000 micrograms of dbcAMP significantly decreased the subsequent effect of CCF (GVBD: 44%) compared with those pre-cultured in a medium with 140 micrograms of dbcAMP/ml (GVBD:5%) or without dbcAMP (GVBD: 15%).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1997

Cumulus cells of oocyte-cumulus complexes secrete a meiosis-activating substance when stimulated with FSH.

The effect of the different follicular cell types on resumption of meiosis was studied during stimulation with FSH. Cumulus enclosed oocytes (CEO), denuded oocytes (DO), and cumulus and mural granulosa cells were used. The resumption of meiosis and oocyte maturation were assessed by the determination of the germinal vesicle breakdown (GVBD) and polar body formation (PB) at the end of a 24 hr culture period in the presence of 4 mM hypoxanthine (HX). The effects of recombinant LH (r-LH) and hCG were also evaluated. Oocyte exposure to the gonadotrophins varied from 5 min to 24 hr (i.e., priming time). Oocytes were obtained from immature gonadotrophin-stimulated and -unstimulated mice. 1. FSH (1 IU/L-75 IU/L) provoked a dose-dependent increase in GVBD and PB in CEO, but not in DO, in stimulated and unstimulated mice. Eight IU/L was sufficient for inducing resumption of meiosis. In contrast, LH and hCG (both 1 IU/L-1500 IU/L) were without effect on GVBD and PB in CEO and DO of oocytes from stimulated and unstimulated mice. A combination of 8 IU/L FSH and 4-8 IU/L hCG produced an additive effect, whereas combinations with LH and higher concentrations of hCG had no such effect. 2. A 2 hr priming with FSH (8 IU/L-75 IU/L) induced a dose-dependent oocyte maturation in CEO. Thirty minutes of priming with FSH (75 IU/L) was sufficient for induction of meiotic resumption in CEO. 3. Priming CEO with FSH for 2 hr followed by the separation and repooling of oocytes and cumulus cells induced oocyte maturation. GVBD of new, unprimed DO added to cumulus cells of primed CEO increased slightly but was significant, whereas GVBD in DO isolated from the primed CEO only increased marginally. DO cocultured with FSH-primed cumulus masses seem to be prevented from resuming meiosis. 4. Priming a coculture of granulosa cells and DO with FSH for 2 hr caused a significant increase in GVBD compared to the control, evaluated after 24 hr. In contrast, a 24 hr FSH-priming of a coculture of granulosa cells and DO was without effect on GVBD. 5. A spent medium in which unstimulated cumulus cells or mural granulosa cells had grown was without effect on GVBD in DO. However, a small fraction of the DO resumed meiosis after culture in a spent medium derived from a 2 hr priming of CEO and spent media from 24 hr priming of CEO induced a 2-3 times higher GVBD frequency in the DO compared to the controls. Heat treatment of spent media (70 degrees C, 30 min) from a 24 hr FSH-priming of CEO still induced GVBD in naive DO. The results showed that FSH, in a concentration of as little as 8 IU/L, but not r-LH and hCG, induced within 30 minutes the cumulus cells to produce and after 2 hr to secrete a diffusible heat stable meiosis activating substance. This substance overcame, in a paracrine fashion, the inhibiting effect of HX and induced oocyte maturation directly in DO. The production of this substance, however, was dependent on the initial connection between the cumulus cells and the oocyte, indicating an important 2-way communication between these 2 cell types. The mural granulosa cells did not produce a meiosis inducing activity by stimulation with FSH, but significantly, more DO matured after coculture with the nonstimulated granulosa cells for 24 hr than for 2 hr. It is proposed that the heat stable meiosis activating component of the spent media from the FSH-stimulated CEO belongs to the meiosis activating sterols, MAS, previously isolated from human follicular fluid and from adult bull testes.

Animals↗
PubMed1994

Effect of cell-plating density on the steroidogenic activity of human cumulus cells.

Expansion of the cumulus mass results in dilution of cumulus cells in accumulated hyaluronic acid. This process is associated with an increase in progesterone secretion. The present study was carried out to evaluate the relationship between these two processes in vitro. Dilution of human cumulus cells was attempted by changing the cell-plating density of cumulus cells in culture. Concurrent with an increase in cell-plating density from 0.25 x 10(4) to 8 x 10(4), progesterone secretion increased by 10.5 times (P < 0.001), 9 times (P < 0.001), and 5.9 times (P < 0.001), and oestradiol secretion increased by 1.4 times (P < 0.001), 1.1 times (P > 0.05), and 2.6 times (P < 0.005) during days 0-3, 3-5, and 5-7 of culture, respectively. However, when steroid secretion was expressed in terms of ng per number of cells, the increase in cell-plating density from 0.25 x 10(4) to 8 x 10(4) coincided with a decrease in progesterone secretion of 3 times (P < 0.001), 3.5 times (P < 0.001), 30 times (P < 0.001), and 12.5 times (P < 0.001) during days 0-3, 3-5, and 5-7 of culture, respectively. The progesterone:oestradiol ratio increased gradually with the increase in cell-plating density. However, at the higher range of cell-plating density the progesterone:oestradiol ratio decreased with extension of the culture period. Addition of human FSH (hFSH) or hCG increased progesterone secretion when the cumulus cells were plated at 2 x 10(4), but in most cases not at 0.25 x 10(4) or 8 x 10(4) cells per dish.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Count↗
PubMed2006

In vivo and in vitro study of porcine oviductal epithelial cells, cumulus oocyte complexes and granulosa cells: a scanning electron microscopy and inverted microscopy study.

The morphology and structure of porcine oviductal epithelial cells (POEC), cumulus-oocyte complexes (COCs) and granulosa cells (GC) were investigated in vivo and in vitro conditions using scanning electron microscopy (SEM) and inverted microscopy. The POEC contained columnar ciliated cells and spherical shaped non-ciliated cells. Both non- and ciliated cells appeared either in groups or distributing among each other. However, the isolation of cells was observed after culture for 48 h. A total of 921 oocytes from 20 ovaries was isolated resulting in an average of 46 oocytes per ovary. They were round in shape, surrounded by zona pellucida with layers of cumulus cells ranging between 89.16 and 144.68 microm in size. As for COCs, they were classified into 4 types; intact-, multi-, partial-cumulus cell layers and completely denuded oocyte. Interestingly, changes in morphology of COCs with intact and multi-cumulus cell layers were observed in the in vitro study. The GCs in the follicular fluid were also round in shape and found as clusters. After culturing in in vitro for 48 h, no change in morphology was observed. The GC appeared in smaller clusters or were present as single cells and their sizes ranged from 6 to 8 microm. The results obtained from this study allow us to have a better understanding of the morphology and nature of cells under both in vivo and in vitro conditions. This information is also important for the study of their secretions and biochemical compositions, which is of great importance to the use of cells as feeder cells in in vitro fertilization in current studies.

Animals↗
PubMed2003

Apoptosis in cumulus cells during in vitro maturation of bovine cumulus-enclosed oocytes.

The aim of this study was to investigate whether apoptosis occurs in cumulus cells during in vitro maturation (IVM) of bovine cumulus-enclosed oocytes (CEOs). The bovine CEOs obtained from ovaries from an abattoir were cultured for 24 h in IVM medium in the presence or absence of 10% (v/v) fetal bovine serum. The developmental competence of enclosed oocytes, as assessed by the development of the blastocyst after IVF, was significantly higher in the serum-treated group than in the control group. The morphological features of apoptosis that were analysed by orcein staining were hardly detectable in the cumulus cells at the start (0 h) of IVM, but were evident at the end (24 h) of IVM both in the control and serum-treated groups. Genomic DNA was extracted from CEOs at 0, 6, 12, 18 and 24 h of IVM and subjected to ligation-mediated PCR (LM-PCR) to detect apoptotic internucleosomal DNA fragmentation. DNA fragmentation was hardly detectable at the start of IVM, but increased in a time-dependent manner as the IVM culture proceeded. DNA fragmentation was not observed in the oocytes, indicating that fragmentation occurs in cumulus cells. The degree of fragmentation was lower in the serum-treated group compared with the control group. The LM-PCR analysis of DNA extracted from CEOs at 24 h of IVM, in which the DNA had been pretreated with Klenow enzyme or T4 DNA polymerase, revealed that the characteristic forms of the DNA ends generated during cumulus cell apoptosis were mainly 3'-overhangs and blunt ends. In conclusion, the results of the present study demonstrate that cumulus cells in bovine CEOs spontaneously undergo apoptosis during IVM. The degree of apoptosis may be correlated with the developmental competence of the enclosed oocytes.

Animals↗
PubMed1995

Gene expressions of oxytocin and oxytocin receptor in cumulus cells of human ovary.

Oxytocin (OT) has been detected in mammalian granulosa-luteal cells during the early stages. The purpose of this study was to explore gene expressions of OT and OT receptor (OTR) in human cumulus cells. Cumulus cells enclosing a mature oocyte were obtained from 6 women undergoing clinical in vitro fertilization and embryo transfer programs. OT and OTR gene expressions were investigated by employing reverse transcription polymerase chain reaction and reverse transcription polymerase chain reaction/single-strand conformation polymorphism methods. OT gene expression in the cumulus cells was positive in 5 women and weakly positive in the remaining patient. The structure of OT mRNA in the cumulus cells was equivalent to that in human hypothalamus. OTR gene expression was also observed in the cumulus cells. This study is the first to describe the simultaneous expression of both OT and OTR genes in human cumulus cells. It is suggested that local OT plays some important roles in fertility through modification of the micro-environment around the oocyte.

Base Sequence↗
PubMed2004

Cell cycle stage analysis of rabbit foetal fibroblasts and cumulus cells.

Synchronization of the cell cycle stages in G0/G1 phase is one of the key factors determining the success of nuclear transplantation. Serum deprivation, contact inhibition and chemical inhibitors are widely used methods for this purpose. In this study, cell cycle stages of foetal fibroblasts and cumulus cells were determined using flow cytometry [fluorescence-activated cell scan (FACS)]. Foetal fibroblasts (in vitro cultured for 72-120 h) and fresh cumulus cells were analysed in Experiment 1. Fifty to 55% proliferating fibroblasts remained in G0/G1 phase compared with 78% in confluent culture (p <0.05). In contrast to foetal fibroblasts, fresh cumulus cells maintained 90% of the population in the G0/G1 stage. When serum was retrieved from the proliferating fibroblasts from day 1 to day 5 (Experiment 2), proportions of G0/G1 cells increased from the initial ratio of 53 to 87% at day 4 of starvation, which was significantly higher than the non-starved proliferating cells (p <0.05). In Experiment 3, fibroblasts were treated with aphidicolin (0.1 microg/ml, 6 h), demicolcine (0.5 microg/ml, 10 h), or a combination of these two chemicals to synchronize the cell cycle stages. Surprisingly, no differences or significantly lower in the proportions of G0/G1)phase cells were detected (25-50%) compared with the uncontrolled growing cells (53%). These results suggested that fresh cumulus cells rest their cell cycle in G0/G1 stage. Serum deprivation became effective in the first 24 h and reached the highest proportions during days 4-5 after deprivation. Chemical synchronization of the cell cycle stage of rabbit foetal fibroblasts to G0/G1 phase appeared less effective compared to serum deprivation.

Animals↗
PubMed2001

Differential effects of insulin-like growth factor-I and gonadotropins on the proliferative activity of two subgroups of granulosa cells: cumulus oophorus and mural granulosa cells.

OBJECTIVE: To evaluate the physiological role of insulin-like growth factor-I (IGFI) and its interaction with gonadotropins in cell replication of two types of granulosa cells (cumulus oophorus, CC) and mural granulosa cells (MGC). DESIGN: Controlled randomized study of the action and interaction of gonadotropins and IGFI on granulosa cell replication in the rat. SETTING: A university reproductive biology laboratory. INTERVENTION(S): The study examined the in vivo treatment with gonadotropins or an analogue of IGFI, long Arg3-insulin-like growth factor (LR3-IGFI), which does not bind to IGFI-binding proteins. MAIN OUTCOME MEASURE(S): Granulosa cell replication was evaluated by the use of 3H-thymidine incorporation. RESULT(S): It was noted that the CC replicate much faster than the MGC. These two types of granulosa cells have very different dose response curves to IGFI. Differential responses were seen in animal cells exposed to long Arg3-insulin-like growth factor in vivo and then exposed to FSH and LH in vitro. CONCLUSION(S): Although murine granulosa cells show proliferative activity when they are exposed to IGFI, the two types, CC and MGC, respond differently. IGFI is not the sole mediator of the action of FSH, and these two chemicals may act independently or in concert.

Animals↗
PubMed1993

Meiotic maturation in cultured bovine oocytes is accompanied by remodeling of the cumulus cell cytoskeleton.

Mammalian oocyte maturation and cumulus expansion are hormone-induced contemporaneous processes that involve changes in cumulus cell shape and in the interactions between cumulus cells and the oocyte. Laser scanning confocal and conventional fluorescence microscopy have been used to study the relationship between reorganization of the cumulus cell cytoskeleton and meiotic progression in bovine cumulus oocyte complexes (COCs) matured in vitro. Inclusion of hormone supplements (FSH, LH, E2) in the maturation media was required for meiotic progression to metaphase 2 and maximal cumulus expansion. Under these conditions, stage-specific changes in the cytoskeletal content and organization of cumulus cell transzonal processes was observed. Specifically, abundant, actin-filled transzonal processes were observed in GV stage COCs. In stages intermediate in the maturation process (10 hr culture), fewer actin-filled transzonal processes were seen and microtubule-filled transzonal processes became apparent. At the end of maturation (24 hr culture), numerous, elongate microtubule rich transzonal processes were evident and actin-filled processes were rarely observed. Additionally, a spatial relationship between microtubule rich transzonal processes and oocyte chromatin was consistently observed in all stages of oocytes examined. These results indicate that bovine oocyte maturation in culture involves modifications of the cumulus cell cytoskeleton that may regulate the onset, progression, and completion of oocyte maturation.

Actins↗
PubMed2005

Cyclic adenosine 3',5'-monophosphate-dependent activation of mitogen-activated protein kinase in cumulus cells is essential for germinal vesicle breakdown of porcine cumulus-enclosed oocytes.

MAPK plays an important role during meiotic maturation in mammalian oocytes, whereas the necessity of MAPK during meiotic resumption in porcine oocytes is still controversial. Here, by applying the method of ultracentrifugation to move the opaque lipid droplets to the edge of the oocyte, therefore allowing clear visualization of porcine germinal vesicles, oocytes just before germinal vesicle breakdown (GVBD) and those that had just undergone GVBD were selected for the assay of MAPK activation. Our results showed that phosphorylation of MAPK in oocytes occurred after GVBD in all three different culture models: spontaneous maturation model, inhibition-induction maturation model, and normal maturation model. Moreover, we found that activation of MAPK in cumulus cells but not in oocytes was essential for GVBD in cumulus-enclosed oocytes. Then the cross-talk between cAMP and MAPK in cumulus cells was investigated by using cell-type-specific phosphodiesterase (PDE) isoenzyme inhibitors. Our results showed that PDE3 subtype existed in oocytes, whereas PDE4 subtype existed in cumulus cells. PDE3 inhibitor prevented meiotic resumption of oocytes, whereas PDE4 inhibitor enhanced the ability of FSH or forskolin to activate MAPK in cumulus cells. We propose that increased cAMP resulting from inhibition of PDE3 in oocytes blocks GVBD, whereas increased cAMP resulting from inhibition of PDE4 activates MAPK pathway in cumulus cells, which is essential for GVBD induction.

Animals↗
PubMed2007

3'5'-cyclic adenosine monophosphate-dependent up-regulation of phosphodiesterase type 3A in porcine cumulus cells.

The means by which cumulus cells react to gonadotropin stimulation and regulate the subsequent production and degradation of cAMP are largely unknown. In this article, we report that cyclic nucleotide phosphodiesterase (PDE) type 3A (Pde3a) is transcriptionally regulated in porcine cumulus cells by a cAMP-dependent pathway during in vitro maturation (IVM). cAMP-PDE activity was increased in the cumulus-oocyte complex (COC) after 10 h of IVM, and 78% of this increase was sensitive to a Pde3-specific inhibitor, cilostamide. Although no variation was observed in the oocyte, cilostamide-sensitive cAMP-PDE activity increased in the cumulus cells after IVM. This was supported by Western blotting, which showed that the intensity of a 135-kDa anti-Pde3a immunoreactive band was increased in COC after IVM. The Pde3a mRNA level was up-regulated 28-fold in the COC after 4 h of IVM and remained high up to 12 h. The mRNA up-regulation and increased activity were inhibited by an RNA synthesis inhibitor, alpha-amanitin. The cilostamide-sensitive increase in PDE activity was inhibited by a protein synthesis inhibitor, cycloheximide. Pregnant mare serum gonadotropin (PMSG) caused dose-dependent activation of Pde3. The PMSG-dependent increase in Pde3 activity and Pde3a mRNA were mimicked by the adenylyl cyclase activator forskolin or prostaglandin E2. PMSG-dependent Pde3 activation was inhibited by the protein kinase A-specific inhibitor H89. Collectively, our results show for the first time that degradation of the intracellular cyclic nucleotide by Pde3a is transcriptionally up-regulated via a cAMP-dependent pathway in cumulus cells, suggesting that it has a functional role during the ovulatory gonadotropin surge.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2004

Relationship between DNA fragmentation and nuclear status of in vitro-matured porcine oocytes: role of cumulus cells.

The present study was conducted to investigate the effects of the attachment of cumulus cells to oocytes and coculture with cumulus cells during maturation culture on the nuclear status and DNA fragmentation of porcine denuded oocytes (DOs). In the first experiment, cumulus cells were removed from cumulus-oocyte complexes (COCs) at 0, 8, 16, 24 or 32 h after the onset of maturation culture and the DOs were then cultured in their original droplets until 42 h of culture was reached. In the second experiment, all COCs were denuded before the onset of culture and the DOs were cocultured with their removed cumulus cells. The DOs were transferred into fresh medium at 0, 8, 16, 24 or 32 h after the onset of coculture with cumulus cells and then cultured until 42 h of culture was reached. After culture, DNA fragmentation and the nuclear status of oocytes were examined using the terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL) method. When the DOs were returned to the same droplets after removal of the cumulus cells, the removal of the cumulus cells after 16 h of culture significantly decreased the proportion of oocytes remaining at the germinal vesicle (GV) stage. However, coculture treatment of DOs in the presence of their removed cumulus cells had no significant effects on the GV breakdown (GVBD) of oocytes. There were no significant differences in the proportion maturing to MII oocytes among the groups following removal of cumulus cells after the onset of maturation culture; however, DOs cocultured with cumulus cells until the end of maturation culture exhibited an increased maturation rate compared with DOs cocultured for 8 and 16 h. The total proportion of TUNEL-positive oocytes of oocytes remaining at the GV stage was higher than that of oocytes reaching other stages, irrespective of the removal of cumulus cells and coculture treatments. However, coculture for more than 16 h decreased the total proportion of TUNEL-positive oocytes. Our results indicate that the attachment of cumulus cells to oocytes may have a critical role for oocytes undergoing GVBD and that coculture with cumulus cells promotes the ability of oocytes to complete maturation. Moreover, coculture with cumulus cells may assist the oocyte to avoid undergoing DNA fragmentation.

Animals↗