PSX-A-19 Late-Breaking: Potential application of granulosa cell derived extracellular vesicles to mitigate the effects of heat stress in bovine oocytes

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 369-369
Author(s):  
Nico G Menjivar ◽  
Samuel Gebremedhn ◽  
Dawit Tesfaye

Abstract Environmental heat stress negatively affects reproductive efficiency by disrupting follicular development, ultimately compromising gamete competency in cattle. Recently, outlined through the bystander effect, granulosa cell derived extracellular vesicles (EVs) were found to suppress negative effects of recurrent heat stress in recipient bovine granulosa cells. Here, we aimed to assess the effects of supplementing granulosa cell derived EVs during bovine in vitro maturation (IVM) on developmental competence following thermal stress. For this, we modeled a cell culture protocol to generate EVs from bovine granulosa cells subjected to differing ambient temperatures, 38.5°C (body temperature) vs. 42°C (heat stress). At the time of IVM, experimental cumulus oocyte complexes (COCs) were arranged in a 2 x 3 factorial design for temperature (38.5°C or 41°C) versus EV supplementation (normal EVs, stressed EVs and non-supplemented controls) at 20% of the IVM media. Following an initial 8h priming period, half the COCs were subjected to heat shock, the others remained at normal temperature to complete IVM. Results indicate that EV supplementation increased cumulus expansion and the expression of cumulus expansion genes (PTX3, PTGS2 and EGFR). Cleavage rates were increased when supplemented with normal (90.2±1.4%; P = 0.023) or stressed (89.8±2.9%; P = 0.029) EVs, compared to the non-supplemented control (80.5±1.5%) under non-thermal conditions. Similarly, exposure to recurrent thermal stress, cleavage rates were (91±0.9%) and (89±0.6%) when supplemented with normal and stressed EVs respectively, compared to the non-supplemented control (88.5±2.5%). In the absence of exposure to recurrent heat stress, blastocysts rates were (32.4±3.5%) and (31.3±2.9%) when COCs were supplemented with normal and stressed EVs, compared to the control (20.7±4.4%). Blastocysts rates were (23.3±4.7%) and (22.5±3.2%) when COCs were supplemented with normal and stressed EVs, compared to the control (15.5±4.5%) when exposed to recurrent thermal stress. In conclusion, granulosa cell derived EVs have potential to induce oocyte tolerance against recurrent thermal stress.

Reproduction ◽  
2017 ◽  
Vol 153 (2) ◽  
pp. R69-R83 ◽  
Author(s):  
Richard J Kordus ◽  
Holly A LaVoie

Cumulus and mural granulosa cells of the ovarian follicle surround and interact with the developing oocyte. These follicular cells reflect the oocyte’s overall health and may indicate subsequent developmental competence of embryos. Biomarkers of granulosa cells associated with individual oocytes could potentially be used in assisted reproduction to indicate which embryos have the best chance of implanting in the uterus and completing gestation. In this review, we have performed a comprehensive assessment of the recent literature for human cumulus and mural granulosa cell mRNA biomarkers as they relate to pregnancy and live birth. A critical discussion of variables affecting granulosa gene expression profiles for in vitro fertilization patients, including patient demographics and ovarian stimulation regimens, is presented. Although studies with microarray data were evaluated, this synopsis focuses on expressed genes that have been validated by quantitative RT-PCR. Furthermore, we summarize the current published data that support or refute identified granulosa expressed genes as potential biomarkers of embryos that give rise to ongoing pregnancy and live birth. Finally, we review studies that offer predictive models for embryo selection for uterine transfer based on biomarkers that show differential gene expression.


Author(s):  
S.B. Khanday ◽  
J.A. Ahmed ◽  
N. Nashiruddullah ◽  
U. Sharma and D. Chakraborty

The aim of the present study was to assess the effect of ascorbic acid on in vitro maturation of caprine oocytes under normal and elevated temperatures. Goat ovaries were collected at slaughter and both A and B grade cumulus-oocyte-complexes (COCs) were aspirated out and were matured in vitro under normal (38.5°C) and elevated temperatures (41°C). On the basis of cumulus expansion and nuclear maturation, the maturation competencewere compared with and without ascorbic acid supplementation (100 µM). Heat stress significantly (P£ 0.01) reduced cumulus expansion, maturation rate and lowered metaphase stage II of nuclear maturation. Ascorbic acid improved developmental competence of oocytes during heat stress (41 °C) and ascorbic acid supplemented COCs demonstrated significantly (P£ 0.05) higher maturation rates when compared to non-supplemented groups.


2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 132-133
Author(s):  
Dawit Tesfaye

Abstract Environmental heat stress negatively affects the fertility of dairy cows by disrupting reproductive processes spanning from follicular development to maternal recognition of pregnancy. Investigation of cellular level responses to stress would contribute to the understanding of the mechanism behind survival responses. Extracellular vesicles (EVs), which carry biologically active signaling molecules, are reported to play a significant role in the cellular response to stress. They are produced by almost all types of cells and abundantly present in various biological fluids including follicular fluid, oviductal fluid, uterine fluids in vivo, and in spent culture media in vitro. Those EV-coupled molecular signals in biological fluids are indicative of the physiological status of the cells of their origin. This has been evidenced by the presence of EV-mediated miRNA signals in follicular fluid associated with the metabolic status of cows. Recent studies revealed the potential role of follicular fluid EVs in carrying molecular signals which can reverse or protect the damage incurred by heat stress in bovine oocytes. In addition to cellular defense responses (activation of HSP70 and HSP90, NRF2 and GRP78 & 94), bovine granulosa cells exposed to heat stress in vitro released EVs enriched with selected mRNA (HSP90 and SOD1) and miRNAs. Among others, miR-1246, miR-374a, and miR-2904 were found to be enriched in EVs released from granulosa cells exposed to thermal stress. Those miRNAs were found to regulate pathways related to heat and endoplasmic reticulum stress responses. The priming of recipient bovine granulosa cells by EVs derived from heat-stressed granulosa cells induced tolerance against recurrent heat stress. Collectively, EV-mediated molecular signals would provide another layer of cell-to-cell communication and deliver protective signals against oxidative stress to recipient cells. This would provide opportunities for future potential application of EVs in tackling oxidative stress-associated fertility problems in humans and animals.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Samuel Gebremedhn ◽  
Ahmed Gad ◽  
Hoda Samir Aglan ◽  
Jozef Laurincik ◽  
Radek Prochazka ◽  
...  

Abstract Elevated summer temperature is reported to be the leading cause of stress in dairy and beef cows, which negatively affects various reproductive functions. Follicular cells respond to heat stress (HS) by activating the expression of heat shock family proteins (HSPs) and other antioxidants. HS is reported to negatively affect the bi-directional communication between the follicular cells and the oocyte, which is partly mediated by follicular fluid extracellular vesicles (EVs) released from surrounding cells. As carriers of bioactive molecules (DNA, RNA, protein, and lipids), the involvement of EVs in mediating the stress response in follicular cells is not fully understood. Here we used an in vitro model to decipher the cellular and EV-coupled miRNAs of bovine granulosa cells in response to HS. Moreover, the protective role of stress-related EVs against subsequent HS was assessed. For this, bovine granulosa cells from smaller follicles were cultured in vitro and after sub-confluency, cells were either kept at 37 °C or subjected to HS (42 °C). Results showed that granulosa cells exposed to HS increased the accumulation of ROS, total oxidized protein, apoptosis, and the expression of HSPs and antioxidants, while the viability of cells was reduced. Moreover, 14 and 6 miRNAs were differentially expressed in heat-stressed granulosa cells and the corresponding EVs, respectively. Supplementation of stress-related EVs in cultured granulosa cells has induced adaptive response to subsequent HS. However, this potential was not pronounced when the cells were kept under 37 °C. Taking together, EVs generated from granulosa cells exposed to HS has the potential to shuttle bioactive molecules to recipient cells and make them robust to subsequent HS.


Reproduction ◽  
2012 ◽  
Vol 144 (2) ◽  
pp. 195-207 ◽  
Author(s):  
Matthew Cotterill ◽  
Sally L Catt ◽  
Helen M Picton

The response of Graafian follicles to pre-ovulatory surge levels of FSH and LH in vivo triggers the terminal differentiation of granulosa cells and oocyte maturation. In polyovular species, the LH-driven signalling uses the epidermal growth factor (EGF)-like ligands AREG, EREG and BTC to promote oocyte maturation and cumulus expansion. This experimental series used a physiologically relevant ovine in vitro maturation (IVM) system to evaluate the impact of exposure to pre-ovulatory levels (100 ng/ml) of LH and FSH on ovine cumulus cell expression of EGF-like ligands in vitro. The serum-free sheep IVM system supported high levels (91.4%) of gonadotrophin-induced maturation of cumulus-enclosed oocytes and embryo development to the blastocyst stage (34.5%). Results were equivalent to a serum-based IVM system (85.1% IVM, 25.8% blastocyst rate; P>0.05) but were significantly different (P<0.05) to serum-free medium without gonadotrophins (69.5% IVM; 8.0% blastocyst rate). Ovine BTC was cloned and sequenced. Gonadotrophin-induced AREG, EREG, BTC and EGFR expressions were quantified in cumulus and mural granulosa cells during IVM. A rapid induction of AREG expression was apparent in both cell types within 30 min of gonadotrophin exposure in vitro. LHCGR (LHR) was detected in mural cells and FSHR in both cumulus and mural granulosa cells. The data confirm the involvement of AREG and EGFR during gonadotrophin-induced cumulus expansion, oocyte maturation and the acquisition of developmental competence by sheep oocytes matured in vitro.


Zygote ◽  
2020 ◽  
pp. 1-5
Author(s):  
Li Ang ◽  
Cao Haixia ◽  
Li Hongxia ◽  
Li Ruijiao ◽  
Guo Xingping ◽  
...  

Summary The present study investigated the effects of c-type natriuretic peptide (CNP) on the development of murine preantral follicles during in vitro growth (IVG). Preantral follicles isolated from ovaries of Kunming mice were cultured in vitro. In the culture system, CNP was supplemented in the experimental groups and omitted in the control groups. In Experiment 1, CNP was only supplemented at the early stage and follicle development was evaluated. In Experiments 2 and 3, CNP was supplemented during the whole period of in vitro culture. In Experiment 2, follicle development and oocyte maturity were evaluated. In Experiment 3, follicle development and embryo cleavage after in vitro fertilization (IVF) were assessed. The results showed that in the control groups in all three experiments, granulosa cells migrated from within the follicle and the follicles could not reach the antral stage. In the experimental groups in all three experiments, no migration of granulosa cells was observed and follicle development was assessed as attaining the antral stage, which was significantly superior to that of the control group (P < 0.0001). Oocyte meiotic arrest was effectively maintained, hence giving good developmental competence. In conclusion, CNP supplementation in the culture system during IVG benefited the development of murine preantral follicles.


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

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


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

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


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