Vascular endothelial growth factor-induced expression of its receptors and activation of the MAPK signaling pathway during ovine oocyte maturation in vitro

Thyroid Transcriptomics Revealed the Reproductive Regulation of miRNA in the Follicular and Luteal Phases in Small-Tail Han Sheep with Different FecB Genotypes

MicroRNA (miRNA) is a type of endogenous short-stranded ncRNA that influences many biological processes such as animal growth, development and metabolism. The thyroid gland is an important endocrine gland in sheep, and an increasing number of studies have shown that the thyroid gland plays an important role in animal reproduction, but the molecular mechanisms of the thyroid gland in sheep reproduction are poorly understood. In this study, RNA-seq was used to detect transcriptome expression patterns in the thyroid gland between the follicular phase (FP) and luteal phase (LP) in FecB BB (MM) and FecB ++ (ww) small-tail Han (STH) sheep, respectively, and to identify differentially expressed miRNAs (DEMs) associated with reproduction. Bioinformatic analysis of the target genes of these DEMs revealed that they can be enriched in multiple GO terms associated with the reproductive process in animals and in the KEGG signaling pathway. The miRNA-mRNA coexpression network revealed that oar-miR-133 and oar-miR-370-3p may play an important role in sheep reproduction. The results of the dual-luciferase reporter assay suggest a possible targeting relationship between novel-51 and TARBP2. These results provided a novel resource for elucidating regulatory mechanisms underlying STH sheep prolificacy.

Identification of differentially abundant mRNA transcripts and autocrine/paracrine factors in oocytes and follicle cells of mud crabs

The late vitellogenic stage of the mud crab is characterized by large and obvious follicle cells as well as an enlarged oocyte nucleus and a prominent germinal vesicle (GV). The aim of this study was evaluation of functions of oocytes and follicle cells during meiosis as well as at identifying associated ovarian autocrine/paracrine factors using comparative transcriptomics. The results from the KEGG pathway analysis indicated DNA replication, nucleotide excision repair, spliceosome and the ribosome pathways were highly associated with oocyte maturation across both transcriptomes. In addition, there was a larger abundance of mRNA transcripts for cell cycle-related genes in the oocyte, as well as cyclin A, cyclin B and CKS1B in the GV than at the time of germinal vesicle breakdown (GVBD). These findings indicate these cell cycle-related genes might be involved in GVBD induction. Results when there was localization of ligands and the respective receptors of VEGF, TGFβ propeptide and BMP9/10 indicated these proteins might be autocrine/paracrine factors. Results from functional analysis of VEGF, TGFβ propeptide and BMP9/10 in oocyte maturation using RNA interference revealed that these proteins might be involved in oocyte maturation by regulating cyclin abundance. This is the first study on the functions of VEGF in oocyte maturation in invertebrates.

Oocyte IVM or vitrification significantly impairs DNA methylation patterns in blastocysts as analysed by single-cell whole-genome methylation sequencing

To explore the mechanisms leading to the poor quality of IVF blastocysts, the single-cell whole-genome methylation sequencing technique was used in this study to analyse the methylation patterns of bovine blastocysts derived from invivo, fresh (IVF) or vitrified (V_IVF) oocytes. Genome methylation levels of blastocysts in the IVF and V_IVF groups were significantly lower than those of the invivo group (P<0.05). In all, 1149 differentially methylated regions (DMRs) were identified between the IVF and invivo groups, 1578 DMRs were identified between the V_IVF and invivo groups and 151 DMRs were identified between the V_IVF and IVF groups. For imprinted genes, methylation levels of insulin-like growth factor 2 receptor (IGF2R) and protein phosphatase 1 regulatory subunit 9A (PPP1R9A) were lower in the IVF and V_IVF groups than in the invivo group, and the methylation level of paternally expressed 3 (PEG3) was lower in the V_IVF group than in the IVF and invivo groups. Genes with DMRs between the IVF and invivo and the V_IVF and IVF groups were primarily enriched in oocyte maturation pathways, whereas DMRs between the V_IVF and invivo groups were enriched in fertilisation and vitrification-vulnerable pathways. The results of this study indicate that differences in the methylation of critical DMRs may contribute to the differences in quality between invitro- and invivo-derived embryos.

Exosomes as a Potential Tool for Supporting Canine Oocyte Development

Simple Summary

To date, extracellular vesicles, including exosomes, have markedly gained attention in scientific research because of their physiological homogeneity as well as stability for transporting regulatory molecules to recipient cells. Recently, it has been shown that exosomes impact gametes and embryo development in several mammalian species; however, there is still scant information on the physiological effects of exosomes on the canine reproduction system. In this regard, we elucidate the possible roles of exosomes involvement in oviduct and cumulus-oocyte complexes mutual communications and how oviduct regulates their development via molecular signaling pathways.

Abstract

The canine oviduct is a unique reproductive organ where the ovulated immature oocytes complete their maturation, while the other mammals ovulate matured gametes. Due to their peculiar reproductive characteristics, the in vitro maturation of dog oocytes is still not wellestablished compared with other mammals. Investigations of the microenvironment conditions in the oviductal canal are required to establish a reliable in vitro maturation system in the dog. Previous studies have suggested that the oviduct and its derivatives play a key role in improving fertilization as well as embryo development. In particular, the biological function of oviduct-derived exosomes on sperm and early embryo development has been investigated in porcine, bovine, and murine species. However, the information about their functions on canine cumulus-oocyte complexes is still elusive. Recent canine reproductive studies demonstrated how oviduct-derived extracellular vesicles such as microvesicles and exosomes interact with oocyte-cumulus complexes and how they can play roles in regulating canine cumulus/oocyte communications. In this review, we summarize the physiological characteristics of canine oviduct-derived exosomes and their potential effects on cumulus cells development as well as oocyte in vitro maturation via molecular signaling pathways.

Maternal Cytokines CXCL12, VEGFA, and WNT5A Promote Porcine Oocyte Maturation via MAPK Activation and Canonical WNT Inhibition

Maternal regulatory factors endow the oocyte with developmental competence in vivo, which might be absent in current in vitro maturation (IVM) systems, thereby compromising oocyte quality. In the present study, by employing RNA sequencing data analysis, we expect to identify potential contributing factors to support porcine oocyte maturation through binding to their receptors on the oolemma. Here, C-X-C motif chemokine ligand 12 (CXCL12), vascular endothelial growth factor A (VEGFA), and Wingless-type MMTV integration site family member 5A (WNT5A), termed CVW, are selected and confirmed to be important maternal cytokines for porcine oocyte maturation. Combined supplementation of CVW promotes the nuclear maturation percentage from 57.2% in controls to 75.9%. More importantly, these maternal cytokines improve the developmental potential of matured oocytes by parthenogenesis, fertilization, and cloning, as their blastocyst formation efficiencies and total cell numbers are increased. CVW supplementation also enlarges perivitelline space and promotes cumulus expansion, which results in a more complete transzonal projection retraction on the zona pellucida, and a reduced incidence of polyspermy in fertilized oocytes. Meanwhile, inhibiting the CVW receptor-mediated signaling pathways severely impairs oocyte meiotic resumption and cumulus expansion during IVM. We further determine that maturation improvement by CVW is achieved through activating the MAPK pathway in advance and inhibiting the canonical WNT pathway at the end of the IVM period. These findings provide a new combination of three cytokines to promote the porcine IVM process, which also holds potential to be used in human assisted reproduction technologies as well as in other species.

[Correlation between follicular fluid sRAGE level and ovarian responsiveness in non-PCOS patients undergoing controlled ovarian hyperstimulation]

OBJECTIVE

To investigate the correlation between soluble receptor for advanced glycation end products (sRAGE) level in the follicular fluid and ovarian responsiveness in non-PCOS patients undergoing controlled ovarian hyperstimulation.

METHODS

Ninety non-PCOS patients underwent IVF/ICSI using a short-acting long protocol for ovarian stimulation with a GnRH agonist. For each patient, the level of sRAGE in the follicular fluid was measured by enzyme linked immunosorbent assay (ELISA), and the data including the clinical baseline state, hormone level, number of oocytes obtained and the fertilization rate were collected.

RESULTS

Follicular fluid sRAGE level showed significant negative correlations with basal FSH level (P=0.0036) and Gn dose (P < 0.0001) and positive correlations with AFC (P < 0.0001), number of oocytes obtained (P < 0.0001), and the fertilization rate (P=0.0047). Follicular fluid sRAGE level was positively correlated with the number of oocytes obtained, and was significantly higher in cases with oocytes obtained above the target number (> 15) than in cases with oocytes obtained within the range of the target numbers (7-15) and below the target number (< 7) (P < 0.0001 and P=0.0012, respectively).

CONCLUSIONS

Follicular fluid sRAGE level can reflect ovarian reserve function in non-PCOS patients, the number of oocytes obtained and the fertilization rate, and can thus predict ovarian responsiveness during controlled hyperstimulation in nonPCOS patients.

Follicular fluid meiosis-activating sterol (FF-MAS) promotes meiotic resumption via the MAPK pathway in porcine oocytes

Follicular fluid meiosis-activating sterol (FF-MAS) exerts beneficial effects on the meiotic resumption of mammalian oocytes and their subsequent early embryonic development, but the signaling pathway underlying these effects has not been elucidated. Therefore, the objective of the present study was to investigate whether the mitogen-activated protein kinase (MAPK) pathway is involved in the FF-MAS-induced in vitro resumption of meiosis in porcine oocytes. Porcine cumulus oocyte complexes (COCs) were allocated in several groups cultured in TCM-199 medium with different concentration of AY 9944-A-7 (20, 30, 40 μmol/L) or ketoconazole (20 μmol/L) to increase or decrease endogenous accumulation of FF-MAS. Each experimental condition was repeated at least six times. After maturation for 44 h, the resumption of meiosis was assessed by the frequency of germinal vesicle breakdown (GVBD) and the first polar body (PBI) extrusion, The relative expressions of related genes in MAPK pathway [c-mos, mitogen-activated protein kinase kinase (MEK) and extracellular signal-regulated kinase 1/2 (ERK1/2)] at both transcriptional and translational levels were detected to investigate the kinetic trend of expression throughout oocyte maturation in vitro in response to the addition of AY 9944-A-7 or ketoconazole to the maturation medium. Results indicated that AY 9944-A-7 promoted, while ketoconazole inhibited, the in vitro maturation (IVM) of porcine oocytes. Relative expression of meiosis related genes was upregulated by AY 9944-A-7 and downregulated by ketoconazole. With extended culturing time, c-mos mRNA expression levels reached their peak at 12 h of maturation and decreased gradually thereafter, while MEK, ERK1 and ERK2 expression increased after an initial decrease peaking at 44 h of culture in the AY 9944-A-7-group. And the trend of the protein expression of c-mos, MEK, ERK1/2 was basically consistent with the mRNA expression of these genes. These results imply that the endogenous accumulation of FF-MAS is beneficial to resumption of meiosis in porcine oocytes and that MAPK signaling is involved in FF-MAS-induced meiotic resumption.

Circular RNA profiling in the oocyte and cumulus cells reveals that circARMC4 is essential for porcine oocyte maturation

Thousands of circular RNAs (circRNAs) have been recently discovered in cumulus cells and oocytes from several species. However, the expression and function of circRNA during porcine oocyte meiotic maturation have been never examined. Here, we separately identified 7,067 and 637 circRNAs in both cumulus cells and oocytes via deep sequencing and bioinformatic analysis. Further analysis revealed that a faction of circRNAs is differentially expressed (DE) in a developmental stage-specific manner. The host genes of DE circRNAs are markedly enriched to multiple signaling pathways associated with cumulus cell function and oocyte maturation. Additionally, most DE circRNAs harbor several miRNA targets, suggesting that these DE circRNAs potentially act as miRNA sponge. Importantly, we found that maternal circARMC4 knockdown by siRNA microinjection caused a severely impaired chromosome alignment, and significantly inhibited first polar body extrusion and early embryo development. Taken together, these results demonstrate for the first time that circRNAs are abundantly and dynamically expressed in a developmental stage-specific manner in cumulus cells and oocytes, and maternally expressed circARMC4 is essential for porcine oocyte meiotic maturation and early embryo development.

Embryotropic effects of vascular endothelial growth factor on porcine embryos produced by in vitro fertilization

Current research suggests that supplementing in vitro culture (IVC) media with vascular endothelial growth factor (VEGF) may have beneficial effects on the development of porcine embryos in vitro. However, the molecular signaling mechanisms underlying this effect are unclear. Therefore, we aimed to investigate the effects of VEGF on molecular signaling events during in vitro embryonic development of porcine embryos. Porcine oocytes matured in vitro were fertilized, and the resultant zygotes were cultured with 5 ng/mL of VEGF supplemented with or without fetal bovine serum from day 4 till day 7. Without VEGF and/or FBS served as the control group. Real-time quantitative PCR was used to detect expression patterns of apoptosis- and oxidative stress-related genes in day 7 blastocysts (BLs). Early-stage apoptosis was detected by annexin-V assays in day 2 and day 7 embryos. We found that the addition of VEGF throughout the culture period with or without FBS supplementation significantly improved embryo survival and development. Supplementation with VEGF in the IVC medium significantly increased early BL formation (p < 0.05), although addition of FBS on day 4 significantly increased hatched BL formation (p < 0.05) regardless of VEGF supplementation. However, supplementation of media with both VEGF and FBS increased the formation of expanded BLs synergistically. The average total cell numbers per BL were significantly (p < 0.05) higher in embryos supplemented with VEGF and FBS than in those supplemented with either VEGF or FBS alone. We also found that accumulation of reactive oxygen species in VEGF-treated embryos was significantly lower (p < 0.05) than that in untreated embryos. The mRNA levels of caspase-3 were significantly lower (p < 0.05), and those of Bcl-2 and Nrf-2 were significantly higher (p < 0.05) in embryos grown in VEGF-supplemented media than in embryos grown in non-supplemented media. Furthermore, on day 2, the numbers of viable embryos (44.06 ± 3.94%) and blastomeres (67.18 ± 3.60%) were significantly higher (p < 0.05), and the numbers of early apoptotic embryos (55.94 ± 3.94) and blastomeres (23.23 ± 4.22) were significantly lower (p < 0.05) in VEGF-treated BLs than in controls. Furthermore, the numbers of early apoptotic cells in BLs on day 7 were also significantly lower (p < 0.05) in VEGF-treated BLs than in controls. Overall, our results indicate that supplementing IVC media with VEGF during in vitro culture of porcine embryos increases their developmental potential.

Widespread changes in transcriptome profile of human mesenchymal stem cells induced by two-dimensional nanosilicates

Two-dimensional nanomaterials, an ultrathin class of materials such as graphene, nanoclays, transition metal dichalcogenides (TMDs), and transition metal oxides (TMOs), have emerged as a new generation of materials due to their unique properties relative to macroscale counterparts. However, little is known about the transcriptome dynamics following exposure to these nanomaterials. Here, we investigate the interactions of 2D nanosilicates, a layered clay, with human mesenchymal stem cells (hMSCs) at the whole-transcriptome level by high-throughput sequencing (RNA-seq). Analysis of cell-nanosilicate interactions by monitoring changes in transcriptome profile uncovered key biophysical and biochemical cellular pathways triggered by nanosilicates. A widespread alteration of genes was observed due to nanosilicate exposure as more than 4,000 genes were differentially expressed. The change in mRNA expression levels revealed clathrin-mediated endocytosis of nanosilicates. Nanosilicate attachment to the cell membrane and subsequent cellular internalization activated stress-responsive pathways such as mitogen-activated protein kinase (MAPK), which subsequently directed hMSC differentiation toward osteogenic and chondrogenic lineages. This study provides transcriptomic insight on the role of surface-mediated cellular signaling triggered by nanomaterials and enables development of nanomaterials-based therapeutics for regenerative medicine. This approach in understanding nanomaterial-cell interactions illustrates how change in transcriptomic profile can predict downstream effects following nanomaterial treatment.

The effects of activated omental extract on nuclear and cytoplasmic in vitro maturation of rat oocytes

Objective:

The role of growth factors, including vascular endothelial growth factor of activated omentum on mitosis is clearly known, though not on all the aspects of in vitro oocyte maturation. This study was designed to assess the effect of activated-omental extract (AOE) on in vitro maturation (IVM) of rat cumulus-oocyte complexes (COCs).

Materials and Methods:

In this experimental study, the COCs were incubated in Ham’s F-10 supplemented with either 20% AOE, 20% fetal bovine serum (FBS) or serum-free media. Post-culture COCs were studied according to the cumulus cells (CCs) expansion, nuclear maturation and cytoplasmic maturation. Cumuli expansion was evaluated by inverted microscope without staining; nuclear maturation was assessed by aceto-orcein staining (light microscope) and cytoplasmic maturation was also observed by TEM.

Results:

Expansion of CCs and nuclear maturation of the oocytes in in vitro for 24 hr was significantly higher in AOE- and FBS-supplemented groups (P=0.000 and 0.013) and (P=0.004 and 0.014), respectively, compared to serum-free group. At ultra-structural level, after 24 hr, both FBS and AOE-supplemented media showed uniformly wide perivitelline space (PVS). After 12 hr, the cortical granules were found in the oocytes cultured in FBS and AOE-supplemented media. Within 24 hr, both granules and mitochondria were large without any detectable topographic tendency across the ooplasm. In AOE and FBS-supplemented oocytes, the number and size of microvilli were more than those in serum-free one.

Conclusion:

Although AOE supplementation induced a higher rate of the CCs expansion, and resuming meiosis, it was not as potent as FBS to provide cytoplasmic maturation of rat oocytes.

Treatment of allicin improves maturation of immature oocytes and subsequent developmental ability of preimplantation embryos

Allicin (AL) regulates the cellular redox, proliferation, viability, and cell cycle of different cells against extracellular-derived stress. This study investigated the effects of allicin treatment on porcine oocyte maturation and developmental competence. Porcine oocytes were cultured in medium supplemented with 0 (control), 0.01, 0.1, 1, 10 or 100 μM AL, respectively, during in vitro maturation (IVM). The rate of polar body emission was higher in the 0.1 AL-treated group (74.5% ± 2.3%) than in the control (68.0% ± 2.6%) (P < 0.1). After parthenogenetic activation, the rates of cleavage and blastocyst formation were significantly higher in the 0.1 AL-treated group than in the control (P < 0.05). The reactive oxygen species level at metaphase II did not significantly differ among all groups. In matured oocytes, the expression of both BAK and CASP3, and BIRC5 was significantly lower and higher, respectively, in the 0.1 AL-treated group than in the control. Similarly, the expression of BMP15 and CCNB1, and the activity of phospho-p44/42 mitogen-activated protein kinase (MAPK), significantly increased. These results indicate that supplementation of oocyte maturation medium with allicin during IVM improves the maturation of oocytes and the subsequent developmental competence of porcine oocytes.

Optimal FSH usage in revascularization of allotransplanted ovarian tissue in mice

Backgroud

Ovarian transplantation is a useful method for preserving the fertility of young women with cancer who undergo radiotherapy and chemotherapy. Follicle-stimulating hormone (FSH) is use to protect transplanted ovarian tissues from ischemia injury through promoting revascularization after transplantation, but the side effect of high level FSH is ovarian overstimulation leading to substantial follicular loss. In this study, we investigated the optimal usage of FSH on revascularization in the in vitro cultured ovarian tissues before and after transplantation.

Results

FSH mainly exhibited an additive response in the gene and protein expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and follicle stimulating hormone receptor (FSHR) with its raised concentrations (0.15 IU/ml, 0.30 IU/ml and 0.60 IU/ml) and prolonged treatment (3 h, 6 h, 12 h, 24 h). The concentrations with 0.60 IU/ml FSH could obviously promoted the expression of VEGF, bFGF and FSHR, but under this concentration FSH could also overstimulated the ovarian tissue leading to follicular loss. With the increase of culture time, the gene and protein expression of VEGF and bFGF both were up-regulated in all of the FSH added groups, but FSHR expression decreased when culture time exceeded 12 h. So we chose 0.30 IU/ml FSH added concentration and 6 h culture time as the FSH usage condition in functional revascularization verification experiment, and found that under this condition FSH promoted 2.5 times increase of vascular density in treated group than in control group after ovarian tissues transplantation.

Conclusion

Ovarian intervention with 0.30 IU/ml FSH for 6 h is an optimal FSH usage condition which could accelerate the revascularization in the allotransplanted ovarian tissue and can not produce ovarian overstimulation.

Influence of vascular endothelial growth factor and Cysteamine on in vitro bovine oocyte maturation and subsequent embryo development

The objective of this study was to investigate the effect of VEGF and Cysteamine during in vitro maturation (IVM) of bovine oocytes on GSH content and developmental competence. For this purpose, experiments were designed to evaluate the effect of 0, 100, 300, and 500 ng/mL VEGF in IVM medium on: GSH content in oocytes and cumulus cells (Exp. 1) and subsequent embryo development (Exp. 2). Also, influence of adding 500 ng/mL VEGF and 100 μM Cysteamine to IVM medium on GSH content in oocytes and cumulus cells (Exp. 3) and oocyte developmental capacity (Exp. 4) were evaluated. Oocytes were matured in: a) Control; b) VEGF 0-3 h; c) Cysteamine 4-24 h; d) VEGF 0-3 h + Cysteamine 4-24 h; and e) VEGF + Cysteamine 24 h. The results showed that: i) VEGF did not alter GSH content in oocytes and cumulus cells; (ii) supplementation of 300 and 500 ng/mL VEGF increased blastocyst yield; (iii) the presence of VEGF + Cysteamine simultaneously during 24 h improved GSH content but not embryo development; and (iv) the presence of VEGF during the first 3 h + Cysteamine from 4 to 24 h increased GSH concentrations and subsequent embryo development. In conclusion, the addition of VEGF and Cysteamine in two sequential steps to maturation medium result in an improvement of cytoplasmic maturation, with a positive impact on oocyte developmental capacity by increasing the efficiency of in vitro blastocyst production. However, the effect was detrimental when both VEGF and Cysteamine were present during 24 of IVM.

Vascular endothelial growth factor A improves quality of matured porcine oocytes and developing parthenotes

Vascular endothelial growth factor is a multipotent angiogenic factor implicated in cell survival and proliferation. The objective was to determine effects of exogenous recombinant human VEGFA (or VEGFA165) in culture media on porcine oocyte maturation and parthenote development. Adding 5 ng/mL VEGFA to the culture medium improved the maturation rate of denuded oocytes (P < 0.05), although 5, 50, or 500 ng/mL did not significantly affect nuclear maturation of oocytes. Parthenotes from oocytes cultured either in in vitro maturation or in vitro culture medium supplemented with 5 or 50 ng/mL VEGFA had an improved blastocyst rate and increased total numbers of cells (P < 0.05). Moreover, those treated with 5 ng/mL of VEGFA had a higher hatched blastocyst rate (average of 121 cells per blastocyst). All VEGFA-treated oocytes had reduced apoptotic indices (P < 0.05), except for those with a higher dose (500 ng/mL) of VEGFA which had more apoptotic cells (P < 0.05). Adding 5 ng/mL VEGFA to oocytes during the last 22 h of in vitro maturation improved (P < 0.05) blastocyst rates and total numbers of cells, with reduced apoptosis indices similar to that of long-term (44 h) culture. Furthermore, Axitinib (VEGFR inhibitor) reversed the effects of VEGFA on parthenote development (P < 0.05). Follicular fluids from medium (2-6 mm) to large (>6 mm) follicles contained 5.3 and 7.0 ng/mL vascular endothelial growth factor protein, respectively, higher (P < 0.05) than concentrations in small (<2 mm) follicles (0.4 ng/mL). Also, VEGFA and its receptor (VEGFR-2) were detected (immunohistochemistry) in growing follicles and developing blastocysts. In addition, VEGFA inhibited caspase-3 activation in matured oocytes (P < 0.05). In conclusion, this is apparently the first report that VEGFA has proliferative and cytoprotective roles in maturing porcine oocytes and parthenotes. Furthermore, an optimal VEGFA concentration promoted porcine oocyte maturation and subsequent development.