Knockdown of melatonin receptor 1 and induction of follicle-stimulating hormone on the regulation of mouse granulosa cell function

Roles of estrogen and its receptors in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is an endocrine disorder characterized by abnormal steroid hormone levels in peripheral blood and poor-quality oocytes. In the ovary, androgen is produced by theca cells, and estrogen is produced by granulosa cells. Androgen is converted to estrogen in granulosa cells, with cytochrome P450 aromatase as the limiting enzyme during this process. Estrogen receptors (ER) include ER alpha, ER beta, and membrane receptor GPR30. Studies have demonstrated that the abnormal functions of estrogen and its receptors and estradiol synthesis-related enzymes are closely related to PCOS. In recent years, some estrogen-related drugs have made significant progress in clinical application for subfertility with PCOS, such as letrozole and clomiphene. This article will elaborate on the recent advances in PCOS caused by abnormal expression of estrogen and its receptors and the application of related targeted small molecule drugs in clinical research and treatment.

Melatonin activates Nrf2/HO-1 signalling pathway to antagonizes oxidative stress-induced injury via melatonin receptor 1 (MT1) in cryopreserved mice ovarian tissue

Our previous research has shown that melatonin (MLT) can reduce cryopreserved ovarian damage in mice. Yet, the molecular mechanism of MLT protection is still unclear. Some studies have shown that melatonin receptor 1 (MT1) is very important for animal reproductive system. To evaluate whether MLT exerts its protective effect on cryopreserved mice ovarian tissue via MT1, we added antagonist of MT1/MT2 (Luzindor) or antagonist of MT2 (4P-PDOT) to the freezing solution, followed by cryopreservation and thawing of ovarian tissue. The levels of total superoxide dismutase (T-SOD), catalase (CAT), nitric oxide (NO) and malondialdehyde (MDA) were detected. Besides, by using RT-PCR and Western blotting, the expression of Bcl-2, Bax and Nrf2/HO-1 signalling pathway-related proteins was detected. These findings demonstrated that compared with the melatonin group, the addition of Luzindor increased apoptosis, NO and MDA activities, decreased CAT and T-SOD activities and inhibited Nrf2/HO-1 signalling pathway. In conclusion, melatonin can play a protective role in cryopreserved ovarian tissue of mice through MT1 receptor.

Melatonin alleviates endoplasmic reticulum stress and follicular granulosa cell apoptosis by regulating ATF4 to activate mTOR signaling pathway in chickens

Follicular atresia in chickens reduces the number of follicles that can further develop, leading to decrease egg laying. Endoplasmic reticulum stress (ERS) can initiate a unique pathway inducing the apoptosis of follicular granulosa cells, thus reducing egg laying. Melatonin (MEL) is involved in the regulation of follicle development, ovulation, and oocyte maturation, and is closely related to follicle fate. Mammalian target of Rapamycin (mTOR) signaling pathway plays an important role in cell growth regulation, and that there is a possible crosstalk between melatonin and mTOR activity in granular cells maturation and ovulation. This study aimed to investigate whether MEL inhibits ERS and follicular granulosa cell apoptosis by regulating ATF4 to activate mTOR signaling pathway in chickens. Frist, we established an in vitro ERS cell model using tunicamycin (TM). The results showed that different concentrations of TM exhibited dose-dependent inhibition of cell activity and induction of granulosa cells (P<0.01). Therefore, we chose 5 µg/mL of TM and a treatment time for 6 h as the optimal concentration for the following experiments. Then we investigate whether melatonin can inhibit ERS. TM treatment decreased the cell viability and Bcl-2 expression, increasing ROS levels and the mRNA expression of Grp78, ATF4, CHOP, PERK, eIF-2α, and BAX (P<0.01), whereas TM+MEL treatment significantly inhibited these changes (P<0.01). Then we explored whether melatonin protects follicular granulosa cells from ERS-induced apoptosis through the mammalian target of rapamycin (mTOR) signaling pathway by regulating ATF4, we found that ATF4 knockdown inhibited ERS by decreasing the expression of ERS-related genes and proteins and activating mTOR signaling pathway by increasing the protein expression of p4E-BP1 and pT389-S6K (P<0.001), while these changes were promoted by TM+si-ATF4+MEL treatment (P<0.01). These results indicate that MEL could alleviate TM-induced ERS by regulating ATF4 to activate mTOR signaling pathway in follicular granulosa cells, thus providing a new perspective for prolonging the laying cycle in chickens.

Melatonin Attenuates Oxidative Stress-Induced Apoptosis of Bovine Ovarian Granulosa Cells by Promoting Mitophagy via SIRT1/FoxO1 Signaling Pathway

Oxidative-stress-induced apoptosis of granulosa cells is considered to be a main driver of follicular atresia. Increasing evidence suggests a protective effect of melatonin against oxidative damage but the mechanism remains unclear. The aim of this study is to investigate the effects of melatonin on mitophagy and apoptosis of bovine ovarian granulosa cells under oxidative stress, and to clarify the mechanism. Our results indicate that melatonin inhibited H2O2-induced apoptosis and mitochondrial injury of bovine ovarian granulosa cells, as revealed by decreased apoptosis rate, reactive oxygen species (ROS) levels, Ca2+ concentration, and cytochrome C release and increased mitochondrial membrane potential (ΔΨm). Simultaneously, melatonin promoted mitophagy of bovine ovarian granulosa cells through increasing the expression of PTEN-induced putative kinase 1 (PINK1), PARKIN, BECLIN1, and LC3II/LC3I; decreasing the expression of sequestosome 1 (SQSMT1); and promoting mitophagosome and lysosome fusion. After treatment with a mitophagy inhibitor CsA, we found that melatonin alleviated apoptosis and mitochondrial injury through promoting mitophagy in bovine ovarian granulosa cells. Furthermore, melatonin promoted the expression of silent information regulator 1 (SIRT1) and decreased the expression level of forkhead transcription factors class O (type1) (FoxO1). By treatment with an SIRT1 inhibitor EX527 or FoxO1 overexpression, the promotion of melatonin on mitophagy as well as the inhibition on mitochondrial injury and apoptosis were reversed in bovine ovarian granulosa cells. In conclusion, our results suggest that melatonin could promote mitophagy to attenuate oxidative-stress-induced apoptosis and mitochondrial injury of bovine ovarian granulosa cells via the SIRT1/FoxO1 signaling pathway.

Melatonin Protects the Apoptosis of Sheep Granulosa Cells by Suppressing Oxidative Stress via MAP3K8 and FOS Pathway

Melatonin is not only a highly effective active oxygen scavenger but also an important reproductive hormone. Melatonin has a regulatory effect on animal reproduction, especially on the ovaries. It can affect the proliferation and apoptosis of cells in follicles. However, the mechanisms of the dual antioxidation and anti-apoptosis effects of melatonin on granulosa cells are still not clear, especially in sheep. Therefore, we investigated the mechanisms of the protective effect of melatonin against oxidative damage in granulosa cells. At a concentration of 250 µmol/L, H₂O₂ promoted granulosa cell apoptosis; however, 10 ng/mL melatonin effectively alleviated the pro-apoptotic effect of H₂O₂. Furthermore, through the application of high-throughput sequencing technology, we identified 109 significantly differentially expressed genes (35 upregulated and 74 downregulated genes) involved in the protective effect of melatonin against apoptosis. The expression levels of nine related genes, i.e., ATF3, FIBIN, FOS, HSPA6, MAP3K8, FOSB, PET117, DLX2, and TRIB1, changed significantly. MAP3K8 and FOS gene overexpression impacted the protective effect of melatonin in granulosa cells; the two genes exhibited an upstream and downstream regulatory relationship. Our findings indicated that melatonin alleviated H₂O₂-induced apoptosis in sheep granulosa cells through the MAP3K8-FOS pathway.

Melatonin alleviates ovarian function damage and oxidative stress induced by dexamethasone in the laying hens through FOXO1 signaling pathway

Oxidative stress can trigger follicular atresia, and decrease follicles quantity in each development stage, thereby alleviating reproductive activity. The induction of oxidative stress in chickens through intraperitoneal injection of dexamethasone is a reliable and stable method. Melatonin has been shown to mitigate oxidative stress in this model, but the underlying mechanism remains unclear. Therefore, this study aimed to investigate whether melatonin can recover aberrant antioxidant status induced by dexamethasone and the specific mechanism behind melatonin-dependent protection. A total of 150 healthy 40-wk-old Dawu Jinfeng laying hens with similar body weights and laying rates were randomly divided into three groups, with five replicates per group and 10 hens per replicate. The hens in the control group (NS) received intraperitoneal injections of normal saline for 30 d, the dexamethasone group (Dex+NS) received 20 mg/kg dose of dexamethasone for the first 15 d, followed by the 15 d of normal saline treatment. While in the melatonin group (Dex+Mel), dexamethasone (20 mg/kg dose) was injected intraperitoneally in the first 15 d, and melatonin (20 mg/kg/d) was injected in the last 15 d. The results showed that dexamethasone treatment significantly enhanced oxidative stress (P < 0.05), while melatonin not only inhibited the oxidative stress but also notably enhanced the antioxidant enzymes superoxide dismutase (SOD), catalase activity (CAT), glutathione peroxidase (GSH-Px), and antioxidant genes CAT, superoxide dismutase 1 (SOD1), glutathione peroxidase 3 (GPX3), and recombinant peroxiredoxin 3 (PRDX3) expression (P < 0.05). Melatonin treatment also markedly reduced 8-hydroxy deoxyguanosine (8-OHdG), malondialdehyde (MDA), and reactive oxygen species (ROS) levels (P < 0.05) and apoptotic genes Caspase-3, Bim, and Bax in the follicle. In the Dex+Mel group, the Bcl-2 and SOD1 protein levels were also increased (P < 0.05). Melatonin inhibited the forkhead Box Protein O1 (FOXO1) gene and its protein expression (P < 0.05). In general, this investigation revealed that melatonin might decrease oxidative stress and ROS by enhancing antioxidant enzymes and genes, activating the antiapoptotic genes, and inhibiting the FOXO1 pathway in laying hens.

Identification of new variants and candidate genes in women with familial premature ovarian insufficiency using whole-exome sequencing

PURPOSE

To identify candidate variants in genes possibly associated with premature ovarian insufficiency (POI).

METHODS

Fourteen women, from 7 families, affected by idiopathic POI were included. Additionally, 98 oocyte donors of the same ethnicity were enrolled as a control group. Whole-exome sequencing (WES) was performed in 14 women with POI to identify possibly pathogenic variants in genes potentially associated with the ovarian function. The candidate genes selected in POI patients were analysed within the exome results of oocyte donors.

RESULTS

After the variant filtering in the WES analysis of 7 POI families, 23 possibly damaging genetic variants were identified in 22 genes related to POI or linked to ovarian physiology. All variants were heterozygous and five of the seven families carried two or more variants in different genes. We have described genes that have never been associated to POI pathology; however, they are involved in important biological processes for ovarian function. In the 98 oocyte donors of the control group, we found no potentially pathogenic variants among the 22 candidate genes.

CONCLUSION

WES has previously shown as an efficient tool to identify causative genes for ovarian failure. Although some studies have focused on it, and many genes are identified, this study proposes new candidate genes and variants, having potentially moderate/strong functional effects, associated with POI, and argues for a polygenic etiology of POI in some cases.

Melatonin for premenstrual syndrome: A potential remedy but not ready

Premenstrual syndrome (PMS), a recurrent and moderate disorder that occurs during the luteal phase of the menstrual cycle and quickly resolves after menstruation, is characterized by somatic and emotional discomfort that can be severe enough to impair daily activities. Current therapeutic drugs for PMS such as selective serotonin reuptake inhibitors are not very satisfying. As a critical pineal hormone, melatonin has increasingly been suggested to modulate PMS symptoms. In this review, we update the latest progress on PMS-induced sleep disturbance, mood changes, and cognitive impairment and provide possible pathways by which melatonin attenuates these symptoms. Moreover, we focus on the role of melatonin in PMS molecular mechanisms. Herein, we show that melatonin can regulate ovarian estrogen and progesterone, of which cyclic fluctuations contribute to PMS pathogenesis. Melatonin also modulates gamma-aminobutyric acid and the brain-derived neurotrophic factor system in PMS. Interpreting the role of melatonin in PMS is not only informative to clarify PMS etiology but also instructive to melatonin and its receptor agonist application to promote female health. As a safe interaction, melatonin treatment can be effective in alleviating symptoms of PMS. However, symptoms such as sleep disturbance, depressive mood, cognitive impairment are not specific and can be easily misdiagnosed. Connections between melatonin receptor, ovarian steroid dysfunction, and PMS are not consistent among past studies. Before final conclusions are drawn, more well-organized and rigorous studies are recommended.

The Effect of Melatonin on OCT4 Expression and Granulosa Cell Growth in Female Mice

Melatonin is mainly secreted by the pineal gland as a neurotransmitter. Moreover, melatonin is also produced by the ovary and plays important roles in female reproduction. However, it is unclear whether melatonin has any effect on the transition from the preantral follicle to the early antral follicle. Octamer-binding transcription factor 4 (OCT4) is important to granulosa cells development, which is regulated by gonadotropin. And these regulations are mediated by the GSK3β/β-catenin pathway via the activated PI3K/Akt signaling. The aim of the present study was to determine the effects and the possible mechanisms of melatonin on ovarian cells development. The results showed that melatonin inhibited granulosa cells development, which was accompanied by the downregulation of OCT4 expression. Meanwhile, melatonin also decreased the expression of p-GSK3β (glycogen synthase kinase 3 beta), p-Akt, β-catenin, and its translocation to the nucleus in granulosa cells. Moreover, melatonin attenuated the effects of FSH in vitro and eCG in vivo on these regulations. In conclusion, this study shows that melatonin inhibits ovarian cell development by downregulating the OCT4 expression level, which is possibly mediated by inhibiting the PI3K/Akt and GSK3β/β-catenin pathway. Melatonin attenuates the effects of gonadotropin on ovarian granulosa cells as a negative regulator.

Cathepsin B Regulates Mice Granulosa Cells' Apoptosis and Proliferation In Vitro

Cathepsin B (CTSB), a lysosomal cysteine protease’s high expression and activity, has been reported to cause poor-quality embryos in porcine and bovine. Nevertheless, CTSB functions in mice granulosa cells remain to explore. To discuss the CTSB functional role in follicular dynamics, we studied apoptosis, proliferation, cell cycle progression, and related signaling pathways in primary mouse granulosa cells transfected with small interference RNA specific to CTSB (siCTSB) for 48 h. Further, mRNA and protein expression of cell proliferation regulators (Myc and cyclin D2), apoptosis regulators (caspase 3, caspase 8, TNF-α, and Bcl2), steroidogenesis-related genes (FSHR and CYP11A1), and autophagy markers (LC3-I and ATG5) were investigated. In addition, the effect of CTSB on steroidogenesis and autophagy was also examined. Flow cytometry analysis assay displayed that silencing of CTSB decreased the early and total apoptosis rate by downregulating TNF-α, caspase 8, and caspase 3, and upregulating Bcl2. By regulating Myc and cyclin D2 expression and activating the p-Akt and p-ERK pathways, CTSB knockdown increased GC proliferation and number. A significant decline in estradiol and progesterone concentrations was observed parallel to a significant decrease in autophagy-related markers LC3-I and ATG5 compared to the control group. Herein, we demonstrated that CTSB serves as a proapoptotic agent and plays a critical role in folliculogenesis in female mice by mediating apoptosis, autophagy, proliferation, and steroidogenesis. Hence, CTSB could be a potential prognostic agent for female infertility.

Melatonin regulates proliferation and apoptosis of endometrial stromal cells via MT1

Endometrial dysfunction is an important factor for implantation failure. The function of the endometrium is regulated by multiple factors like sex hormones and circadian rhythms. Endometrial stromal cells (ESCs) are a major cellular component in the endometrium, which is essential for proper physiological activities of the endometrium and the establishment of pregnancy. Melatonin, as a circadian-controlled hormone, plays beneficial roles in the regulation of reproductive processes. MT1, a melatonin receptor, can regulate cell proliferation and apoptosis. Whether melatonin-MT1 signal affects biological function of ESCs remains unknown. Here, we showed that MT1 was expressed in human ESCs (hESCs), which could be regulated by estrogen and progesterone. MT1 knockdown inhibited proliferative activity and promoted apoptosis of hESCs by activating caspase-3 and upregulating the Bax/Bcl2 ratio. Melatonin could reverse the effect of MT1 knockdown on proliferative activity and apoptosis of hESCs. Melatonin could promote proliferative activity of hESCs via the JNK/P38 signal pathway and repress the apoptosis of hESCs via the JNK signal pathway. Moreover, in vivo experiments showed that MT1 expression was decreased in endometrial cells from mice with disrupted circadian rhythm, accompanied by increased apoptosis and suppressed proliferative activity, which could be alleviated by administration of melatonin. These results showed the regulatory effect of melatonin-MT1 signal on biological behaviors of ESCs, which might provide a novel therapeutic strategy for endometrial dysfunction induced by disrupted circadian rhythm.

Melatonin improves development, mitochondrial function and promotes the meiotic resumption of sheep oocytes from in vitro grown secondary follicles

The aim of this study was to evaluate follicular survival and development of ovine isolated secondary follicles cultured in medium containing fixed or sequential concentrations of melatonin and further oocyte maturation. Isolated secondary follicles were cultured for 18 days in α-MEM⁺ alone (control) or with different concentrations of melatonin (100, 500 or 1000 pg/mL) or sequential concentrations of melatonin (Mel Seq: Day 6 = 100; Day 12 = 500; Day 18 = 1000 pg/mL). The percentages of morphologically normal follicles and antral cavity formation increased significantly in 1000 pg/mL melatonin compared to the other treatments. After 18 days, 1000 pg/mL melatonin (Mel 100) showed a greater (P < 0.05) follicular diameter than α-MEM⁺, 100 and 500 pg/mL melatonin. In addition, the concentration of 500 pg/mL melatonin showed a higher (P < 0.05) percentage of fully grown oocytes than α-MEM⁺, Mel 100 and Mel Seq treatments. After oocyte maturation, the levels of ROS were lower (P < 0.05) in 1000 pg/mL melatonin (Mel 1000) than in other treatments. Both Mel 1000 and Mel Seq treatments showed significantly higher levels of mitochondrial activity than other treatments. There were no significant differences between 500 and 1000 pg/mL melatonin regarding meiotic stages. In conclusion, the concentration of 1000 pg/mL melatonin maintains survival, promotes follicular development and increases the levels of active mitochondria after in vitro culture of sheep secondary follicles. Moreover, this concentration promotes the meiotic competence of oocytes and decreases the production of ROS during oocyte maturation.

Fetal liver mesenchymal stem cells restore ovarian function in premature ovarian insufficiency by targeting MT1

Background

With the development of regenerative medicine and tissue engineering technology, almost all stem cell therapy is efficacious for the treatment of premature ovarian failure (POF) or premature ovarian insufficiency (POI) animal models, whereas little stem cell therapy has been practiced in clinical settings. The underlying molecular mechanism and safety of stem cell treatment in POI are not fully understood. In this study, we explored whether fetal mesenchymal stem cells (fMSCs) from the liver restore ovarian function and whether melatonin membrane receptor 1 (MT1) acts as a regulator for treating POI disease.

Methods

We designed an in vivo model (chemotherapy-induced ovary damage) and an in vitro model (human ovarian granulosa cells (hGCs)) to understand the efficacy and molecular cues of fMSC treatment of POI. Follicle development was observed by H&E staining. The concentration of sex hormones in serum (E2, AMH, and FSH) and the concentration of oxidative and antioxidative metabolites and the enzymes MDA, SOD, CAT, LDH, GR, and GPx were measured by ELISA. Flow cytometry (FACS) was employed to detect the percentages of ROS and proliferation rates. mRNA and protein expression of antiapoptotic genes (SURVIVIN and BCL2), apoptotic genes (CASPASE-3 and CASPASE-9), and MT1 and its downstream genes (JNK1, PCNA, AMPK) were tested by qPCR and western blotting. MT1 siRNA and related antagonists were used to assess the mechanism.

Results

fMSC treatment prevented cyclophosphamide (CTX)-induced follicle loss and recovered sex hormone levels. Additionally, fMSCs significantly decreased oxidative damage, increased oxidative protection, improved antiapoptotic effects, and inhibited apoptotic genes in vivo and in vitro. Furthermore, fMSCs also upregulated MT1, JNK1, PCNA, and AMPK at the mRNA and protein levels. With MT1 knockdown or antagonist treatment in normal hGCs, the protein expression of JNK1, PCNA, and AMPK and the percentage of proliferation were impaired.

Conclusions

fMSCs might play a crucial role in mediating follicular development in the POI mouse model and stimulating the activity of POI hGCs by targeting MT1.

Melatonin Reduces Androgen Production and Upregulates Heme Oxygenase-1 Expression in Granulosa Cells from PCOS Patients with Hypoestrogenia and Hyperandrogenia

Background/Aims

Polycystic ovary syndrome (PCOS) is an endocrine disorder characterized by abnormal hormone levels in peripheral blood and poor-quality oocytes. PCOS is a pathophysiological syndrome caused by chronic inflammation and oxidative stress. The aim of this study was to investigate the mechanism of melatonin regulation on androgen production and antioxidative damage in granulosa cells from PCOS patients with hypoestrogenia and hyperandrogenia.

Methods

Cumulus-oocyte complexes were collected from PCOS patients who had low levels of estrogen in follicular fluids.

Results

Melatonin triggered upregulation of cytochrome P450 family 19 subfamily A member 1 (CYP19A1) expression via the extracellular signal-regulated kinase pathway in luteinized granulosa cells. As a result, conversion of androgen to 17β-estradiol was accelerated. We also found that melatonin significantly reduced the levels of inducible nitric oxide (NO) synthetase and NO in luteinized granulosa cells. Levels of transcripts encoding NF-E2-related factor-2 and its downstream target heme oxygenase-1 were also increased, leading to anti-inflammatory and antioxidant effects. We also found that melatonin could improve oocyte development potential.

Conclusion

Our preliminary results showed that melatonin had a positive impact on oocyte quality in PCOS patients with hypoestrogenia and hyperandrogenia.

Effect of melatonin on regulation of apoptosis and steroidogenesis in cultured buffalo granulosa cells

This study was aimed to address melatonin receptor expression, mRNA level of hypothalamus and hypophysis hormone receptors (GnRHR, FSHR, and LHR), steroidogenesis, cell cycle, apoptosis, and their regulatory factors after addition of melatonin for 24 hr in cultured buffalo granulosa cells (GCs). The results revealed that direct addition of different concentrations of melatonin (100 pM, 1 nM, and 100 nM) resulted in significant upregulation (p < 0.05) of mRNA level of melatonin receptor 1a (MT1) without affecting melatonin receptor 1b (MT2). Melatonin treatment significantly downregulated (p < 0.05) mRNA level of FSH and GnRH receptors, whereas 100 nM dose of melatonin significantly increased mRNA level of LH receptor. Treatment with 100 nM of melatonin significantly decreased the basal progesterone production with significant decrease (p < 0.05) in mRNA levels of StAR and p450ssc, and lower mRNA level of genes (Insig1, Lipe, and Scrab1) that affect cholesterol availability. Melatonin supplementation suppressed apoptosis (100 nM, p < 0.05) and enhanced G2/M phase (1 nM, 100 nM, p < 0.05) of cell cycle progression which was further corroborated by decrease in protein expression of caspase-3, p21, and p27 and increase in bcl2. Our results demonstrate that melatonin regulates gonadotrophin receptors and ovarian steroidogenesis through MT1. Furthermore, the notion of its incorporation in apoptosis and proliferation of buffalo GCs extends its role in buffalo ovaries.

Melatonin-induced demethylation of antioxidant genes increases antioxidant capacity through RORα in cumulus cells of prepubertal lambs

Physical damage and oxidative stress may occur in prepubertal cumulus cells, due to insufficient glutathione synthesis. To determine potential epigenetic mechanisms related to antioxidant effects of melatonin on ovine prepubertal cumulus cells, 30 lambs, 4-wk-old were randomly allocated into two groups: a control (C, n = 20) group and a melatonin (M, n = 10) group given a subcutaneous implant containing 18 mg melatonin. All lambs were superovulated (250 IU FSH and 250 IU eCG). Cumulus cells from germinal vesicle stage cumulus oocyte complexes (COCs) were collected by ovarian follicular aspiration and dissociated with hyaluronidase. Compared to the C group, the M group had greater superovulation, better antioxidant capacity, a higher proportion of fully expanded COCs and a lower proportion of apoptotic cumulus cells (P < 0.05). Melatonin up-regulated mRNA expression of genes for melatonin receptors MT1 and nuclear binding site RORα, antioxidants (SOD1, GPx4 and CAT) and cumulus cell expansion (PTX3, HAS2 and PTGS2), as well as Bcl2, but down-regulated expression of Bax (P < 0.05). Regarding epigenetics, there were less methylation at five CpG sites of SOD1, three CpG sites of GPx4 and two CpG sites of CAT in M versus C groups (P <  0.05), leading to lower total methylation of SOD1, GPx4 and CAT promoters region on M group (P < 0.05). In a mechanistic study, addition of MT1 or RORα antagonist increased ROS and MDA concentrations, but decreased T-AOC, GPx, CAT and T-SOD concentrations (P < 0.05), whereas there were no significant difference between the melatonin and MT2 antagonist treatment groups for T-AOC, GPx, CAT and T-SOD concentrations. Furthermore, addition of RORα agonist decreased total DNA methylation of SOD1, GPx4 and CAT, with no significant difference after MT1 agonist treatment. These studies provided new information regarding epigenetic mechanisms by which melatonin promoted ovine prepubertal cumulus cells antioxidant through RORα, both in vitro and in vivo.

Regulatory roles of ephrinA5 and its novel signaling pathway in mouse primary granulosa cell apoptosis and proliferation

Recent findings suggest that ephrinA5 (Efna5) has a novel role in female mouse fertility, in addition to its well-defined role as a neurogenesis factor. Nevertheless, its physiological roles in ovarian granulosa cells (GC) have not been determined. In this study, mouse GC were cultured and transfected with ephrin A5 siRNA and negative control to determine the effects of Efna5 on GC apoptosis, proliferation, cell cycle progression, and related signaling pathways. To understand the mode signaling, the mRNA expression levels of Efna5 receptors (Eph receptor A5, Eph receptor A3, Eph receptor A8, and Eph receptor B2) were examined. Both mRNA and protein expressions of apoptosis-related factors (Bax, Bcl-2, Caspase 8, Caspase 3, and Tnfα) and a proliferation marker, Pcna, were investigated. Additionally, the role of Efna5 on paracrine oocyte-secreted factors and steroidogenesis hormones were also explored. Efna5 silencing suppressed GC apoptosis by downregulating Bax and upregulating Bcl-2 in a Caspase 8-dependent manner. Efna5 knockdown promoted GC proliferation via p-Akt and p-ERK pathway activation. The inhibition of Efna5 enhanced BMH15 and estradiol expression, but suppressed GDF9, while progesterone level remained unaltered. These results demonstrated that Efna5 is a pro-apoptotic agent in GC and plays important role in folliculogenesis by mediating apoptosis, proliferation, and steroidogenesis in female mouse. Therefore Efna5 might be potential therapeutic target for female fertility disorders.

Melatonin-Mediated Development of Ovine Cumulus Cells, Perhaps by Regulation of DNA Methylation

Cumulus cells of pre-pubertal domestic animals are dysfunctional, perhaps due to age-specific epigenetic events. This study was designed to determine effects of melatonin treatment of donors on methylation modification of pre-pubertal cumulus cells. Cumulus cells from germinal vesicle stage cumulus oocyte complexes (COCs) were collected from eighteen lambs which were randomly divided into control group (C) and melatonin group given an 18 mg melatonin implant subcutaneous (M). Compared to the C group, the M group had higher concentrations of melatonin in plasma and follicular fluid (p < 0.05), greater superovulation, a higher proportion of fully expanded COCs, and a lower proportion of apoptotic cumulus cells (p < 0.05). Real-time PCR results showed that melatonin up-regulated expression of genes MT1, Bcl2, DNMT1, DNMT3a and DNMT3b, but down-regulated expression of genes p53, Caspase 3 and Bax (p < 0.05). Furthermore, melatonin increased FI of FITC (global methylation level) on cumulus cells (p < 0.05). To understand the regulation mechanism, the DNMTs promoter methylation sequence were analyzed. Compared to the C group, although there was less methylation at two CpG sites of DNMT1 (p < 0.05) and higher methylation at two CpG sites of DNMT3a (p < 0.05), there were no significant differences in methylation of the detected DNMT1 and DNMT3a promoter regions. However, there were lower methylation levels at five CpG sites of DNMT3b, which decreased methylation of detected DNMT3b promoter region on M group (p < 0.05). In conclusion, alterations of methylation regulated by melatonin may mediate development of cumulus cells in lambs.