192 The effect of invitro maturation on the PI3K-Akt pathway in bovine cumulus cells

2020 ◽  
Vol 32 (2) ◽  
pp. 224
Author(s):  
G. Andrade ◽  
M. Del Collado ◽  
R. Nociti ◽  
W. J. Da Silva ◽  
F. Meirelles ◽  
...  

Oocyte quality is influenced by invitro oocyte maturation (IVM) because the culture conditions can alter the metabolism and gene expression of cumulus cells. Proper oocyte development requires fine regulation of signalling pathways involved with cell proliferation and survival, such as the PI3K-Akt (phosphatidylinositol-3-kinase/protein kinase B) signalling pathway. The aim of this study was to determine the effect of IVM on the expression of PI3K-Akt-related genes in bovine cumulus cells. To this aim, cumulus cells associated with immature oocytes, associated with oocytes invitro-matured for 24h, or associated with oocytes invivo-matured were compared in terms of gene expression. Pools (n=4) of cumulus cells from 20 cumulus-oocyte complexes (COCs) per group were submitted to total RNA extraction using the TRizol protocol, libraries were prepared with TruSeq stranded mRNA sample prep kit (Illumina Inc.), and the sequencing was performed in the HisEqn 2500 V4 (Illumina Inc.). After quality check with FastQC and filtering with Trim Galore, read alignment was performed with STAR and analysis of differential gene expression was done using DESEqn 2 in R considering the Benjamini-Hochberg method for adjusted P-values<0.10, and absolute value of log2-fold change >0.5. Principal component analysis was able to separate, with 94% cumulative variance (81% and 13% for PC1 and PC2, respectively), the cumulus cells groups, especially the immature from the matured counterparts. Gene ontology and enrichment analysis showed that the PI3K-Akt signalling pathway was affected in immature cumulus cells compared with cumulus cells from invitro- or invivo-matured oocytes, with 77 and 88 genes from PI3K-Akt pathway being differentially expressed, respectively. A total of 51 genes were common in invivo- and invitro-matured oocytes cumulus cells groups compared with immature group. Regarding cumulus cells after the maturation process, 48 genes from the PI3K-Akt pathway were differentially expressed; of those, 26 genes were upregulated in cumulus cells from invitro-matured oocytes and 22 genes were upregulated in cumulus cells from invivo-matured oocytes. Comparing the invitro and invivo cumulus cells, the main genes of the pathway (AKT, PI3K, and PTEN) were not differentially expressed. The differences in expression between invitro and invivo cumulus cells were in genes responsible for different cellular functions controlled by the PI3K-Akt pathway, such as apoptosis, protein synthesis, and DNA repair, among others, which, in general, were increased in cumulus cells from invitro-matured oocytes. These results demonstrated the effect of culture conditions on cumulus cell gene expression modulating important pathways involved in oocyte competence acquisition, such as PI3K-Akt signalling. Financial support was provided by FAPESP grants 2014/22887-0, 2018/01431-9, and 2018/13155-6.

2021 ◽  
Vol 22 (4) ◽  
pp. 1901
Author(s):  
Brielle Jones ◽  
Chaoyang Li ◽  
Min Sung Park ◽  
Anne Lerch ◽  
Vimal Jacob ◽  
...  

Mesenchymal stromal cells derived from the fetal placenta, composed of an amnion membrane, chorion membrane, and umbilical cord, have emerged as promising sources for regenerative medicine. Here, we used next-generation sequencing technology to comprehensively compare amniotic stromal cells (ASCs) with chorionic stromal cells (CSCs) at the molecular and signaling levels. Principal component analysis showed a clear dichotomy of gene expression profiles between ASCs and CSCs. Unsupervised hierarchical clustering confirmed that the biological repeats of ASCs and CSCs were able to respectively group together. Supervised analysis identified differentially expressed genes, such as LMO3, HOXA11, and HOXA13, and differentially expressed isoforms, such as CXCL6 and HGF. Gene Ontology (GO) analysis showed that the GO terms of the extracellular matrix, angiogenesis, and cell adhesion were significantly enriched in CSCs. We further explored the factors associated with inflammation and angiogenesis using a multiplex assay. In comparison with ASCs, CSCs secreted higher levels of angiogenic factors, including angiogenin, VEGFA, HGF, and bFGF. The results of a tube formation assay proved that CSCs exhibited a strong angiogenic function. However, ASCs secreted two-fold more of an anti-inflammatory factor, TSG-6, than CSCs. In conclusion, our study demonstrated the differential gene expression patterns between ASCs and CSCs. CSCs have superior angiogenic potential, whereas ASCs exhibit increased anti-inflammatory properties.


2014 ◽  
Vol 26 (2) ◽  
pp. 337 ◽  
Author(s):  
Satoko Matoba ◽  
Katrin Bender ◽  
Alan G. Fahey ◽  
Solomon Mamo ◽  
Lorraine Brennan ◽  
...  

The follicle is a unique micro-environment within which the oocyte can develop and mature to a fertilisable gamete. The aim of this study was to investigate the ability of a panel of follicular parameters, including intrafollicular steroid and metabolomic profiles and theca, granulosa and cumulus cell candidate gene mRNA abundance, to predict the potential of bovine oocytes to develop to the blastocyst stage in vitro. Individual follicles were dissected from abattoir ovaries, carefully ruptured under a stereomicroscope and the oocyte was recovered and individually processed through in vitro maturation, fertilisation and culture. The mean (± s.e.m.) follicular concentrations of testosterone (62.8 ± 4.8 ng mL–1), progesterone (616.8 ± 31.9 ng mL–1) and oestradiol (14.4 ± 2.4 ng mL–1) were not different (P > 0.05) between oocytes that formed (competent) or failed to form (incompetent) blastocysts. Principal-component analysis of the quantified aqueous metabolites in follicular fluid showed differences between oocytes that formed blastocysts and oocytes that degenerated; l-alanine, glycine and l-glutamate were positively correlated and urea was negatively correlated with blastocyst formation. Follicular fluid associated with competent oocytes was significantly lower in palmitic acid (P = 0.023) and total fatty acids (P = 0.031) and significantly higher in linolenic acid (P = 0.036) than follicular fluid from incompetent oocytes. Significantly higher (P < 0.05) transcript abundance of LHCGR in granulosa cells, ESR1 and VCAN in thecal cells and TNFAIP6 in cumulus cells was associated with competent compared with incompetent oocytes.


2006 ◽  
Vol 18 (2) ◽  
pp. 270
Author(s):  
C. Hanna ◽  
C. Long ◽  
M. Westhusin ◽  
D. Kraemer

The objectives of this study were to determine whether the percentage of canine oocytes that resume meiosis during in vitro maturation could be increased by either increasing culture duration or by removing approximately one-half of the cumulus cells 24 h after oocytes were placed into culture. Canine female reproductive tracts were collected from a local clinic and ovaries were minced in warm TL-HEPES. Oocytes with a consistently dark ooplasm and at least two layers of cumulus cells were selected, cultured in a basic canine oocyte in vitro maturation medium consisting of TCM-199 with Earl's salts, 2.92 mM Ca-lactate, 20 mM pyruvic acid, 4.43 mM HEPES, 10% fetal calf serum, 1% Penicillin/Streptomycin (GibcoBRL, Grand Island, NY, USA), and 5 μg/mL porcine somatotropin, and incubated at 38.5°C in 5% CO2 in humidified air. Treatment groups were randomly assigned and oocytes were cultured for 60, 84, or 132 h (Basic). From each of these groups, one-half of the oocytes were pipetted through a fine bore pipette to partially remove the cumulus cells 24 h after the start of culture (Basic–1/2). At the end of culture, all oocytes were denuded and the nuclear status was observed with Hoechst 33342 under ultraviolet fluorescence. All data were analyzed by ANOVA with P < 0.05. Since the canine oocyte is ovulated at the germinal vesicle (GV) stage of meiosis and requires up to five days to mature in the oviduct, it was hypothesized that an increased culture time would allow for more oocytes to undergo nuclear maturation to metaphase II (MII). It was also hypothesized that partial removal of cumulus cells would decrease the cumulus cell component in the ooplasm that sustains meiotic arrest, allowing for more oocytes to resume meiosis (RM = germinal vesicle breakdown to MII). Results within each treatment group indicate that there is no significant difference between culture duration and the percent of oocytes that mature to MII. Additionally, there was no significance in the percent of oocytes that resumed meiosis after partial cumulus cell removal. Taken together, these data suggest that neither treatment is effective in canine in vitro maturation systems, given the current maturation culture conditions. Table 1. Nuclear status* of oocytes for three time periods with or without partial cumulus cell removal


2009 ◽  
Vol 21 (1) ◽  
pp. 195 ◽  
Author(s):  
R. R. Payton ◽  
L. A. Rispoli ◽  
J. L. Edwards

It is well established that exposure of cumulus–oocyte complexes (COC) to heat stress during the first 12 h of maturation reduces blastocyst development by 42 to 65%. Previous research supports the notion that some of the effects of heat stress on oocyte competence may be cumulus-mediated. To determine the extent to which this may occur, COC were matured at 38.5°C for 24 h (control) or 41°C for the first 12 h of maturation followed by 38.5°C for remaining 12 h (heat stress). A subset of COC underwent IVF with Percoll-prepared sperm and then was cultured in KSOM containing 0.5% BSA to assess developmental competence. Remaining oocytes were denuded. Cumulus cells, kept separate by treatment, were stored in lysis buffer at –80°C until RNA extraction. Total RNA from cumulus was amplified prior to hybridization to bovine Affymetrix GeneChips (Affymetrix Inc., Santa Clara, CA, USA; n = 8 pools per treatment collected on 8 different occasions; n = 16 chips). Following pre-processing using the MAS5.0 algorithm, microarray data were subjected to linear modeling and empirical Bayes analyses (Bioconductor, Limma package). False discovery rate was controlled using the Benjamini and Hochberg method, and differentially expressed genes were selected by an adjusted P-value (P < 0.05). Functional annotation of selected genes was performed using NetAffx (Affymetrix Inc.) and Database for Annotation, Visualization and Integrated Discovery (DAVID; NIAID, NIH, Bethesda, MD, USA). Heat stress of COC reduced blastocyst development (27.2 v. 16.1% for control v. heat stress, respectively; SEM = 1.6; P < 0.002). Approximately 66 and 65% of 24 000 possible genes were called present (i.e. expressed) in RNA from cumulus of competent (control) v. challenged (heat-stressed) oocytes, respectively. In cumulus from developmentally challenged COC, increased abundance of 42 genes (36 currently annotated) was noted. Use of DAVID demonstrated enrichment of genes important for electron transport and energy generation (NOS2A, MAOB, CYP11A1, HSD11B1L, LTB4DH). Further examination of gene ontology identified genes associated with mitochondrial function (SLC25A10, MAOB, CYP11A1), cell signaling (similar to JAK-3, FSHR, CYP11A1, WNT2B), cytoskeleton (ACTA1), antioxidant activity (GSTA1), and extracellular region (FMOD). In contrast, cumulus from developmentally competent COC had increased expression of 22 genes (20 currently annotated), of which 15% were related to protein binding (CAV1, MMP9, TGFB2) according to DAVID. Further analysis using gene ontology revealed genes associated with extracellular matrix formation (MMP9, MMP19, PCOLCE2) and neural tissue (METRNL). In summary, alterations in cumulus gene expression were associated with differences in developmental competence of oocytes. Additional research is necessary to examine the extent to which identified genes account for functional differences in oocyte competence. This research was supported in part by National Research Initiative Competitive Grant no. 2004-35203-14772 from the USDA Cooperative State Research, Education, and Extension Service.


2016 ◽  
Vol 28 (2) ◽  
pp. 160
Author(s):  
S. Lee ◽  
C. Khoirinaya ◽  
J.-X. Jin ◽  
G. A. Kim ◽  
B.-C. Lee

In vitro studies on mammalian oocytes have shown that follicular fluid-meiosis activating sterol (FF-MAS) can overcome the inhibitory effect of hypoxanthine (Hx) on the resumption of meiosis. FF-MAS, an intermediate in the cholesterol biosynthesis pathway, is converted to testis meiosis–activating sterol by a sterol Δ14-reductase. AY9944 A-7, an inhibitor of Δ14-reductase and Δ7-reductase, induces accumulation of FF-MAS by inhibiting its metabolism. The aim of this study was to evaluate the effects of AY9944 A-7 on meiotic resumption of porcine oocytes, cumulus cell expansion, and gene expression related to M-phase-promoting factor (MPF), mitogen-activated protein kinase (MAPK), and oocyte maturation in oocytes and related to cumulus expansion in cumulus cells. In experiment 1, 1136 cumulus-oocyte complexes (COCs) were cultured in IVM media with 4 different concentrations (0, 10, 20, and 40 μM) of AY9944 A-7 in addition to a meiotic inhibitor (Hx, 4 mM) for 44 h. Oocytes treated with 10 and 20 μM AY9944 A-7 in the presence of Hx had significantly higher GVBD and M2 rates than the control group. However, 40 μM AY9944 A-7 significantly decreased GVBD and M2 rates and increased degeneration of oocytes compared with other groups. In experiment 2, 600 COCs were cultured in IVM media with 4 different concentrations (0, 10, 20, and 40 μM) of AY9944 A-7 in the absence of Hx for 44 h. Cumulus expansion of 40 μM AY9944 A-7 treated group was significantly decreased compared with other groups. In experiment 3, we evaluate the effects of AY9944 A-7 on gene expression, and the experiment was replicated four times. Data on gene expression were analysed using Student’s t-test. Oocytes treated with 10 μM AY9944 A-7 increased expression of genes involved in MPF (Cyclin B and Cdc2), MAPK (C-mos), and oocyte maturation (GDF9 and BMP15). Cumulus cells treated with 10 μM AY9944 A-7 decreased cumulus expansion-related genes (Has2, Tnfaip6, Ptgs2, and Ptx-3). In conclusion, our results suggest that although 10 μM AY9944 A-7 decreased cumulus expansion-related genes, there was no difference in cumulus expansion and it induced meiotic resumption of porcine oocytes with increased MPF, MAPK, and oocyte maturation-related genes. Further studies are needed to evaluate the effect of AY9944 A-7 on porcine embryo development. This study was supported by Ministry Of Trade, Industry & Energy (#10048948), Korea IPET (#114059–3), Research Institute for Veterinary Science, TS Corporation, and the BK21 plus program.


2018 ◽  
Vol 30 (1) ◽  
pp. 226
Author(s):  
F. C. Castro ◽  
L. Schefer ◽  
K. L. Schwarz ◽  
H. Fernandes ◽  
R. C. Botigelli ◽  
...  

Melatonin mediates several processes in animal reproduction and has drawn attention for its potent antioxidant, anti-apoptotic, anti-inflammatory action and, more recently, for its benefits on oocyte maturation and embryo development in vitro. The aim of this study was to assess the effect of melatonin during the in vitro maturation (IVM) on nuclear maturation of bovine oocytes and gene expression in their corresponding cumulus cells (CC). Bovine cumulus–oocyte complexes (COC) were obtained by aspiration of follicles (2-6 mm) from slaughterhouse ovaries, selected (grades I and II) and transferred to 4 well plates (25-30 COC/well) containing IVM medium [TCM-199 supplemented with sodium bicarbonate (26 mM), sodium pyruvate (0.25 mM), FSH (0.5 µg mL−1), LH (5.0 µg mL−1), 0.3% BSA, and gentamicin (50 µg mL−1)] with 0, 10−5, 10−7, 10−9 or 10−11 M melatonin and cultured for 24 h at 38.5°C and 5% CO2. At the end of IVM, oocytes were stained with Hoechst 33342 (10 μg mL−1) and evaluated for nuclear maturation rate. The CC were evaluated for the expression of antioxidant (SOD1, SOD2, GPX4), pro-apoptotic (P53, BAX) and expansion-related genes (PTX3, HAS1, HAS2). For transcript detection in CC, RNA isolation was performed with TRIzol®Reagent (Invitrogen, Carlsbad, CA, USA) and reverse transcription with High Capacity cDNA Reverse Transcription kit (Applied Biosystems, Foster City, CA, USA). Relative quantification of transcripts was performed by RT-qPCR using 3 endogenous controls (β-actin, GAPDH, PPIA). Nuclear maturation rate and gene expression were tested by ANOVA and means were compared by Tukey’s test (6 replicates). In CC, the different concentrations of melatonin did not significantly alter expression of the investigated genes (P > 0.05), although all concentrations provided a numerical increase in the expression of the antioxidant SOD1 and of the expansion-related genes PTX3 and HAS2. Regarding the pro-apoptotic genes, concentrations of 10−11 and 10−9 M were able to reduce only numerically the expression of BAX and P53, respectively. In oocytes, the rate of nuclear maturation was not different among the tested treatments (P > 0.05), but it was numerically higher in the 10−7 M melatonin treated group compared with the control (69.71 ± 13.76% v. 88.1 ± 12.54%). In conclusion, under the studied conditions, melatonin was unable to improve maturation rate or to affect the expression of antioxidant, pro-apoptotic, and expansion-related genes in CC. Melatonin during IVM has shown variable results in different studies and appears to show different effects depending on culture conditions and parameters studied. In order to take advantage of the possible positive antioxidant effects of melatonin, other culture conditions and parameters should be investigated. In a next step, melatonin will be included during in vitro culture of embryos to evaluate its possible cytoprotective role, because such embryos are more exposed to oxidative stress during in vitro culture, and to investigate its benefits on developmental competence in vitro. This reaesrch was funded by FAPESP (2015/20379-0; 2014/17181-0).


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 5548-5548
Author(s):  
Rosalia Di Stefano ◽  
Elena Baiamonte ◽  
Melania Lo Iacono ◽  
Barbara Spina ◽  
Flavia Contino ◽  
...  

Abstract Introduction: Genetic modification of autologous hematopoietic stem and progenitor cells (HSPC) is a promising clinical intervention to cure inherited monogenic diseases. Successful gene therapy trials have already been conducted using CD34+ cells from bone marrow and from mobilized peripheral blood. In this regard, cord blood (CB) represents an attractive source of HSCs due to its high concentration of high proliferative HSPC and increased susceptibility to be transduced by lentiviral vectors. Unfortunately, the major disadvantage is the limited number of HSC in the CB collection. Consequently, ex-vivo expansion of CB-HSC is desirable to extend clinical applications. Purposes: To investigate the ability of UCB-cd34+ cells to be expanded in serum-free media supplemented with the early acting hematopoietic cytokines SCF,TPO and Flt-3 ligant (STF) and to characterize CD34+ cells subtypes, clonogenic capacity and gene expression profile during expansion. We also wanted to investigate the susceptibility of the expanded cd34+ cells to be transduced by a GFP-lentiviral vector (LV-GFP) Material and Methods: CD34+ immunoselected cells from 10 UCB were grown for 8 days in customized serum-free medium formulated for HSC expansion, supplemented with STF cytokines. Numbers end frequency of CD34+cells and co-expression of the primitive surface antigens (CD38, CD133, CD90) was evaluated during expansion. Colonies developed in methylcellulose were scored for enumeration ad typing. LV-GFP transduction efficiency was evaluated in CD34+ cells cultured for 4 days in expansion medium plus STF and for 24 hrs in X-vivo10 medium with STF±IL-3 cytokines; the last condition slightly expands CD34+ cells (1.3 fold) and are currently used for HSPC-lentivector transduction in gene therapy clinical trials. The transduction efficiency was evaluated by measuring the percentage of GFP+ cells in the bulk and in colonies developed in methylcellulose and the VCN/cell by Q-PCR. Gene expression profiles were analyzed by human whole genome Agilent microarray Technology to detect differentially expressed genes between expanded, ex-vivo medium cultured and un-cultured cells. Results: We found an average of 8 fold-increase CD34+cells at day 4 and of 22 fold- increase at day 8 of culture. The frequency of CD34+ was maintained at day 4 and declined of about 50% at day 8. CD34+/CD38- early progenitors doublet as early as day 4, differences in CD34+/CD133+ and CD34+/CD90+cells were not significant. The number of CFU slightly increased during expansion while the relative frequency of colonies type did not significantly changed. Four days expanded CD34+ cells were transduced more efficiently than those grown in ex-vivo medium even in presence of IL-3 added to the STF cytokine cocktail. Comprehensive gene expression profile analysis highlighted about 4000 genes differentially expressed in CD34+ cells expanded for 4 and for 8 days compared to that of the un-cultured cells. Conversely, the expression profiles analysis did not show any clear separation between different cell culture methods (expansion vs ex-vivo medium). Specifically, the number of differentially expressed genes in common between the different culture conditions compared with the un-cultured cells was statistically significant. Unsurprisingly, the common up-regulated genes were related to the cell cycle. The likeness between the gene expression profiles of the different culture conditions was also validated by the identification of a significantly small number of differentially expressed genes between them. Conclusions: UCB-CD34+ cells can be efficiently expanded and transduced in serum free conditions. The expanded cells exhibited phenotypic marchers typical of early progenitors and developed colonies in number and in type similar to the unmanipulated cells and exhibited whole gene expression profile that is consisted with that of CD34+ cells exposed for the short term culture conditions currently used in gene therapy trial mediated by lentiviral vectors. Results from this study open a window on the future possibility of using homologous UCB-HSC as target for gene correction in patients diagnosed for a genetic disorder in prenatal time. The genetically modified cells would be stored and used for gene therapy in the same individual in pediatric age. This work was funded by the F and P Cutino Foundation - Project RiMedRi CUP G73F12000150004 Disclosures No relevant conflicts of interest to declare.


2020 ◽  
Vol 38 (15_suppl) ◽  
pp. e15155-e15155
Author(s):  
Jie Wu ◽  
Weihua Huang ◽  
Changhong Yin ◽  
Yee Him Cheung ◽  
Debra Abrams ◽  
...  

e15155 Background: Novel immunotherapies are becoming a viable option for advanced lung cancer treatment. High-throughput gene expression profiling (GEP) has enabled better understanding of patient responsiveness to targeted immunotherapy. However, non-invasive blood-based signatures are needed to monitor and predict response. Methods: To evaluate the predictive and prognostic role of blood-based GEP, we designed a longitudinal study by enrolling 15 patients with advanced lung cancers. A total of 65 samples were collected for RNA sequencing, ~4 blood specimens per patient, before and during anti-PD-1 treatment. We used multiple analyses, including time-course differential gene expression, principal component, lymphocyte compartment deconvolution, and genetic mutation, to search for and assess potential predictive and prognostic aspects. Results: Of 15 patients, 11 were classified as Responders (partial responders) and four were Non-Responders (one stable and three progressive diseases). Our analyses demonstrated: 1) By comparing baseline GEPs from Responders vs. Non-Responders before the first treatment, we identified potential markers (e.g., LY6E is significantly lower expressed in Responders, with Log2 Fold change = -3.44 and p = 1.83E-04) that can be used as predictors of responsiveness of the patients; 2) Immunoglobulin subunits- and T cell receptor complex-related genes were differentially expressed in Responders (DAVID analysis, p = 6.7E-3 and 2.1E-2, respectively), but not in Non-responders; 3) γδ T cells in the lymphocyte compartment were relatively increased in Responders; 4) Despite a different set of genes differentially expressed at different time points, the biggest GEP changes were at ~ week 6, after the second treatment. Additionally, we observed certain genes consistently up- or down-regulated through the whole course of treatment. Furthermore, after the first treatment, genes in the immune response pathway were regulated to different directions in Responders and Non-Responders. For example, interleukin receptor genes, such as IL18R1 and IL18RAP, and CD24 were down-regulated in Responders, but up-regulated in Non-Responders (p = 0.042, 0.023 and 0.044 respectively, t-test for the differential expression in these two groups). Conclusions: The utility of blood GEP to identify predictive and prognostic factors for precision immunotherapy is encouraging. Nevertheless, these results, predictive of the anti-PD-1 clinical response, are preliminary and need to be validated in a larger cohort.


2008 ◽  
Vol 20 (5) ◽  
pp. 579 ◽  
Author(s):  
E. C. Curnow ◽  
J. Ryan ◽  
D. Saunders ◽  
E. S. Hayes

Glutathione (GSH) is the main non-enzymatic defence against oxidative stress and is a critical intracellular component required for oocyte maturation. In the present study, several modulators of intracellular GSH were assessed for their effect on the in vitro maturation (IVM) and intracellular GSH content of bovine metaphase (MII) oocytes. Of the five GSH modulators tested, only the cell-permeable GSH donor glutathione ethyl ester (GSH-OEt) significantly increased the GSH content of IVM MII oocytes in a concentration-dependent manner without adversely affecting oocyte maturation rate. The GSH level in IVM MII oocytes was greatly influenced by the presence or absence of cumulus cells and severely restricted when oocytes were cultured in the presence of buthionine sulfoximine (BSO), an inhibitor of GSH synthesis. The addition of GSH-OEt to cumulus-denuded or BSO-treated oocytes increased the GSH content of bovine MII oocytes. Supplementation of the maturation medium with bovine serum albumin (BSA) or fetal calf serum (FCS) affected the GSH content of IVM MII oocytes, with greater levels attained under BSA culture conditions. The addition of GSH-OEt to the maturation medium increased the GSH content of IVM MII oocytes, irrespective of protein source. Spindle morphology, as assessed by immunocytochemistry and confocal microscopy, displayed distinct alterations in response to changes in oocyte GSH levels. GSH depletion caused by BSO treatment tended to widen spindle poles and significantly increased spindle area. Supplementation of the IVM medium with GSH-OEt increased spindle length, but did not significantly alter spindle area or spindle morphology. GSH-OEt represents a novel oocyte-permeable and cumulus cell-independent approach for effective elevation of mammalian oocyte GSH levels.


2009 ◽  
Vol 21 (9) ◽  
pp. 33
Author(s):  
T. S. Hussein ◽  
A. N. Filby ◽  
R. B. Gilchrist ◽  
M. Lane

Interactions between the oocyte and its companion somatic cells are crucial to establish and maintain a highly specialized microenvironment required for oocyte viability. Specifically, cumulus cell expansion in the mouse is reliant on oocyte-secreted factors (OSF). Little is know about factors secreted by the human oocyte and how they may interact with cumulus cells. Therefore, the aim of this study was to establish whether human cumulus oocyte complexes (COC) produce OSF that induces cumulus expansion. COC of patients undergoing routine clinical IVF were cultured individually for 6h following oocyte retrieval. The human oocyte conditioned medium (HOCM) was collected. The bioactivity of OSF in the HOCM was assessed using an established assay of cumulus expansion of mouse oocytectomized complexes (OOX). Cumulus expansion was assessed blinded using the scoring system; 1 (no expansion) to 4 (maximally expanded) and gene expression was assessed by real time RT-PCR. Culture of OOX in control media with or without FSH did not induce expansion. Similarly, OOX cultured in HOCM without FSH did not expand. However, culture of OOX in HOCM with FSH significantly induced expansion (2.4±0.1 compared with control 1.1±0.04, P<0.05). Furthermore, this expansion was not different to OOX co-cultured with human (2.9±0.1) or mouse (2.6±0.1) denuded oocytes. Cumulus/OOX gene expression of hyaluronan synthase-2 and cyclooxygenase-2 was significantly up-regulated 4-5 fold when OOX were cultured in HOCM compared to control (P<0.05). Interestingly, different patients produced HOCM which resulted in different levels of expansion (range from 1.5-3.7). This study has established that human COC secrete paracrine factor(s) that enable cumulus expansion. This expansion was dependent on the presence of FSH. The identity of these factor(s) are currently unknown however it appears that COC from different patients produce differing levels of these cumulus expansion enabling factor(s).


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