MicroRNAs: New Insight in Modulating Follicular Atresia: A Review

MiR-302c-3p regulates autophagy and apoptosis in ovarian granulosa cells via the LATS2/YAP axis in chickens

The degenerative process of follicular atresia in hens naturally commences in granulosa cells, significantly impacting laying hens' reproductive performance. Past studies suggested that granulosa cell autophagy and apoptosis work together to cause follicular atresia. Recent research indicates that miRNA regulates granulosa autophagy and apoptosis, which contributes to the development of follicular atresia. However, the role of miR-302c-3p in follicular atresia and development remains unclear. In this study with the RNA-seq approach, we found that miR-302c-3p expression was significantly decreased in atrophic follicles, suggesting its involvement in the follicular atresia process. Following this, we performed in vitro studies to confirm that miR-302c-3p inhibits autophagy and apoptosis in chicken granulosa cells. Mechanistically, LATS2 is considered as the putative target gene of miR-302c-3p, and it has been demonstrated that LATS2 exerts a positive regulatory role in the modulation of autophagy and apoptosis in chicken granulosa cells. Furthermore, we verified the regulatory function of miR-302c-3p in chicken granulosa cells via the LATS2-YAP signaling pathway. Our results collectively demonstrates that miR-302c-3p targets LATS2 to modulate the YAP signaling pathway, impacting autophagy and apoptosis in granulosa cells leading to follicular atresia.

A Case of Follicular Atresia Triad Combined with Necrotising Fasciitis and Squamous Carcinoma of the Lower Limbs

Follicular atresia triad, also known as paradoxical acne (FOT), is a rare and serious clinical syndrome in dermatology, mainly manifested by coalescing acne, purulent perifolliculitis of the head, and suppurative sweating inflammation, and FOT combined with necrotising fasciitis of the lower limbs and squamous cell carcinoma is rare both at home and abroad. In this article, we share the clinical data and treatment of a patient with follicular atresia triad and necrotising fasciitis and squamous cell carcinoma of the left lower limb for your reference.

Effect of follicle-stimulating hormone and luteinizing hormone on apoptosis, autophagy, and the release and reception of some steroid hormones in yak granulosa cells through miR-23a/ASK1 axis

Follicle-stimulating hormone (FSH), luteinizing hormone (LH), miR-23a, apoptosis signal-regulating kinase 1(ASK1)/c-Jun N-terminal kinase (JNK), autophagy and apoptosis play crucial roles in follicular development. However, their role in yak granulosa cells (GCs) remains unknown. Therefore, we examined the effect of miR-23a, ASK1, FSH, and LH on apoptosis, autophagy, and the release and reception of some steroid hormones in these cells. Our results showed that miR-23a overexpression significantly increased the abundance of Beclin1, the LC3II/I ratio, and the number of Ad-mRFP-GFP-LC3-labeled autophagosomes, and decreased p62 abundance. Additionally, Bax abundance and the number of terminal deoxynucleotidyl transferase deoxynucleotide triphosphate nick end labeling-positive cells were reduced, while Bcl2 expression was increased. Overexpression of miR-23a also significantly increased the abundance of estradiol receptor α (ER-α) and β (ER-β) and the concentrations of estradiol (E2), progesterone (P4) in yak GCs. Here, treating yak GCs with miR-23a decreased ASK1 expression, which regulates ASK1/JNK-mediated apoptosis, autophagy, E2 and P4 levels, and ER-α/β abundance. In contrast, treatment of yak GCs with FSH (10 μg/mL) and LH (100 μg/mL) increased miR-23a abundance, regulating the subsequent effect on ASK1/JNK-mediated apoptosis, autophagy, ER-α/β abundance, and E2 and P4 concentrations. In conclusion, miR-23a enhances autophagy in yak GCs, attenuates apoptosis, and increases ER-α/β abundance and E2 and P4 concentrations by downregulating ASK1. Additionally, FSH and LH can regulate these effects of miR-23a by altering its expression. These results provide important insights that can inform the development of strategies to reduce abnormal follicular atresia and improve the reproductive rate of yaks.

miRNA profiling of chicken follicles during follicular development

MicroRNAs (miRNAs) play a crucial role as transcription regulators in various aspects of follicular development, including steroidogenesis, ovulation, apoptosis, and gene regulation in poultry. However, there is a paucity of studies examining the specific impact of miRNAs on ovarian granulosa cells (GCs) across multiple grades in laying hens. Consequently, this study aims to investigate the roles of miRNAs in chicken GCs. By constructing miRNA expression profiles of GCs at 10 different time points, encompassing 4 pre-hierarchical, 5 preovulatory, and 1 postovulatory follicles stage, we identified highly expressed miRNAs involved in GC differentiation (miR-148a-3p, miR-143-3p), apoptosis (let7 family, miR-363-3p, miR-30c-5p, etc.), and autophagy (miR-128-3p, miR-21-5p). Furthermore, we discovered 48 developmentally dynamic miRNAs (DDMs) that target 295 dynamic differentially expressed genes (DDGs) associated with follicular development and selection (such as oocyte meiosis, progesterone-mediated oocyte maturation, Wnt signaling pathway, TGF-β signaling pathway) as well as follicular regression (including autophagy and cellular senescence). These findings contribute to a more comprehensive understanding of the intricate mechanisms underlying follicle recruitment, selection, and degeneration, aiming to enhance poultry's reproductive capacity.

miRNA-29-3p targets PTEN to regulate follicular development through the PI3K/Akt/mTOR signaling pathway

Granulosa cells play a pivotal role in growth, development and ovulation of ovarian follicle. Simultaneously, autophagy and apoptosis processes are crucial determinants in the destiny of granulosa cells. Within this context, miR-29-3p, known to regulate a broad spectrum of biological processes and critical for tumor detection, prognosis, and treatment, is poised to clarify its roles in both autophagy and apoptosis. To enhance the understanding of the influence of miR-29-3p on follicular development, our study primarily delved into the realms autophagy and apoptosis. We employed a well-established chicken follicular atrophy model achieved through subcutaneous injection of tamoxifen (TMX) into hens. qPCR analysis revealed a significant decrease in the expression of miR-29-3p within the atrophic follicles. In our in vitro experiments with cultured chicken primary granulosa cells, miR-29-3p emerged as a novel microRNA capable of impeding autophagy and apoptosis when transfected with miR-29-3p mimics and inhibitors. Results from luciferase reporter assays corroborated that PTEN is a legitimate target of miR-29-3p. Unlike miR-29-3p, PTEN appeared to foster autophagy and apoptosis in chicken granulosa cells. Moreover, our findings uncovered that miR-29-3p facilitates the phosphorylation of Akt and mTOR proteins by targeting PTEN in chicken granulosa cells. In conclusion, the findings of this study suggest that miR-29-3p, through its targeting of PTEN via the Akt/mTOR signaling pathway, exerts inhibitory effects on autophagy and apoptosis. These effects may hold significant importance in the context of follicular development.

MiR-23a promotes autophagy of yak cumulus cells to alleviate apoptosis via the apoptosis signal-regulating kinase 1/c-Jun N-terminal kinase pathway

The ultimate fate of Graafian follicles is ovulation or atresia which relies on the highly coordinated processes of apoptosis and autophagy in ovarian cells. Long non-coding RNA maternally expressed gene 3 (LncRNA MEG3), miR-23a, and apoptosis signal-regulating kinase 1 (ASK1) are factors associated with autophagy. However, whether these factors can regulate autophagy in cumulus cells (CCs) of yak is unclear. Here, miR-23a overexpression upregulated the LC3-II/LC3-I ratio and Beclin1 abundance while reducing p62 accumulation (p < 0.05). The monodansylcadaverine assay exhibited a marked increase in punctate green fluorescence, and the GFP-LC3B displayed increased yellow fluorescence (p < 0.05). The opposite effect was observed for miR-23a inhibitors. Furthermore, miR-23a overexpression downregulated the abundance of ASK1 mRNA and total ASK1 protein (t-ASK1), whereas miR-23a inhibitors up-regulated them (p < 0.05). The effects of miR-23a overexpression on ASK1 phosphorylated protein at serine 845 (P-845), total JNK (c-Jun N-terminal kinase) (t-JNK) and the JNK phosphorylated protein (p-JNK) were similar to those of t-ASK1 but elicited the opposite effect on ASK1 phosphorylated protein at serine 967 (P-967) (p < 0.05). We further demonstrated that ASK1 expression can be silenced by small-interfering RNA (siRNA), which had no significant effect on t-JNK abundance (p > 0.05) but significantly suppressed the p-JNK expression (p < 0.05). Silencing ASK1 significantly improved Beclin1 abundance and the LC3-II/LC3-I ratio, but decreased p62 abundance (p < 0.05). An increase in yellow GFP-LC3B puncta and green MDC staining puncta were observed (p < 0.05). Overexpression of LncRNA MEG3 significantly increased the expression of t-ASK1, P-845, and JNK and decreased the abundance of P-967 and miR-23a (p < 0.05). In addition, miR-23a upregulation reduced the number of the TUNEL-positive cells, and the addition of 8 mM 3-methyladenine (3-MA) reversed this downregulation (p < 0.05). Similar trends were observed for the Bax/Bcl2 ratio and cleaved-caspase3 abundance. In summary, miR-23a promotes autophagy by inhibiting ASK1 abundance, which reduces apoptosis of yak CCs. This effect can be inhibited by LncRNA MEG3, which has implications for decreasing abnormal Graafian follicular atresia and maintaining development.

Copper exposure induces ovarian granulosa cell apoptosis by activating the caspase-dependent apoptosis signaling pathway and corresponding changes in microRNA patterns

Environmental copper (Cu) contamination is a complex worldwide public health problem. However, information on the effects of Cu pollution on human reproduction is limited. Although our previous studies have indicated that Cu exposure disrupts ovarian folliculogenesis, the underlying mechanism needs to be further explored. In this study, human luteinized ovarian granulosa cells and a rat animal model were used to investigate whether Cu exposure affects ovarian follicle development by inducing apoptosis and to elucidate the possible mechanisms. The results showed that Cu exposure from weaning to sexual maturity significantly decreased the proportion of preantral follicles but increased the proportion of atretic follicles (P < 0.05). In addition, 6 mg/kg Cu increased the proportion of antral follicles, while 12 and 25 mg/kg Cu decreased it (P < 0.05). We also found that 6 mg/kg Cu exposure inhibited apoptosis of ovarian granulosa cells, while 12 and 25 mg/kg Cu promoted apoptosis (P < 0.05). Experiments on primary human luteinized ovarian granulosa cells suggested that higher levels of Cu exposure induced a significant increase in the mRNA levels of Bcl2 Bax , Fas, Caspase8, and Caspase3 (P < 0.05), and the protein levels of BAX, BCL2, CASPASE3, CASPASE8, CLE-CASPASE3, CLE-CASPASE8 and BAX/BCL2 were also increased (P < 0.05). miRNA chip analyses identified a total of 95 upregulated and 10 downregulated miRNAs in human luteinized granulosa cells exposed to Cu. Hsa-miR-19b-3p, hsa-miR-19a-3p, miR-548ar-3p, hsa-miR-652-5p, and hsa-miR-29b-5p were decreased after Cu exposure (P < 0.05). Additionally, the level of hsa-miR-144-5p was increased (P < 0.05). Together, our results reveal that Cu exposure induces abnormal ovarian folliculogenesis by inducing ovarian granulosa cell apoptosis, which is triggered by the caspase-dependent apoptosis signaling pathway, and that miRNAs may be involved in this process.

LncRNA MEG3 regulates ASK1/JNK axis-mediated apoptosis and autophagy via sponging miR-23a in granulosa cells of yak tertiary follicles

Apoptosis and autophagy in granulosa cells (GCs) are highly related to follicular development and atresia. It has also been reported that they are related to LncRNA MEG3, miR-23a and apoptosis signal-regulating kinase 1 (ASK-1). However, their relationship to follicular development and the extent to which follicle stimulating hormone (FSH) or luteinizing hormone (LH) can regulate this process remain unknown. Here, we found that ASK1 and JNK were expressed in the GCs of gonadotropin-dependent follicles, and those levels were significantly higher (p < 0.05) in yak Tertiary follicles compared to that of Secondary follicles and Graafian follicles. Then, the effect of LncRNA MEG3 / miR-23a on apoptosis and autophagy via ASK1/JNK (c-Jun N-terminal kinase) in yak GCs was studied. Overexpressing LncRNA MEG3 reduced miR-23a levels and p-967 protein expression, but enhanced ASK1 and JNK mRNA levels as well as t-ASK1, p-845, t-JNK, and p-JNK proteins levels. And Up-regulation of LncRNA MEG3 promoted apoptosis while attenuating autophagy. The targeting relationship between miR-23a and the binding sites of LncRNA MEG3 and ASK1 was also confirmed with the dual luciferase reporter assay. And, the relationship between LncRNA MEG3 and miR-23a was observed as a negative feedback regulation, and changes in LncRNA MEG3 and miR-23a levels can alter the expression of ASK1/JNK axis in yaks GCs. In addition, FSH (10 μg/mL) or LH (100 μg/mL) ability to reverse the effects of LncRNA MEG3 on miR-23a levels and ASK1/JNK axis-mediated apoptosis and autophagy was verified in yak GCs. This is significantly beneficial for decreasing abnormal follicular atresia for yaks tertiary follicles.

MiR-202-5p Regulates Geese Follicular Selection by Targeting BTBD10 to Regulate Granulosa Cell Proliferation and Apoptosis

The regulation of granulosa cells (GCs) proliferation and apoptosis is the key step in follicular selection which determines the egg production performance of poultry. miR-202-5p has been reported to be involved in regulating the proliferation and apoptosis of mammalian ovarian GCs. However, its role in regulating the proliferation and apoptosis of goose GCs is still unknown. In the present study, the GCs of pre-hierarchical follicles (phGCs, 8-10 mm) and those of hierarchical follicles (hGCs, F2-F4) were used to investigate the role of miR-202-5p in cell proliferation and apoptosis during follicle selection. In phGCs and hGCs cultured in vitro, miR-202-5p was found to negatively regulate cell proliferation and positively regulate cell apoptosis. The results of RNA-seq showed that BTB Domain Containing 10 (BTBD10) is predicted to be a key target gene for miR-202-5p to regulate the proliferation and apoptosis of GCs. Furthermore, it is confirmed that miR-202-5p can inhibit BTBD10 expression by targeting its 3'UTR region, and BTBD10 was revealed to promote the proliferation and inhibit the apoptosis of phGCs and hGCs. Additionally, co-transfection with BTBD10 effectively prevented miR-202-5p mimic-induced cell apoptosis and the inhibition of cell proliferation. Meanwhile, miR-202-5p also remarkably inhibited the expression of Phosphatidylinositol-4,5-Bisphosphate 3-Kinase Catalytic Subunit Beta (PIK3CB) and AKT Serine/Threonine Kinase 1 (AKT1), while it was significantly restored by BTBD10. Overall, miR-202-5p suppresses the proliferation and promotes the apoptosis of GCs through the downregulation of PIK3CB/AKT1 signaling by targeting BTBD10 during follicular selection. Our study provides a theoretical reference for understanding the molecular mechanism of goose follicular selection, as well as a candidate gene for molecular marker-assisted breeding to improve the geese' egg production performance.

Erxian decoction alleviates cisplatin-induced premature ovarian failure in rats by reducing oxidation levels in ovarian granulosa cells

ETHNOPHARMACOLOGICAL RELEVANT

Erxian Decoction (EXD) has been used empirically for more than 70 years to treat premature ovarian failure (POF), but more research is needed to understand how it works.

AIM OF THE RESEARCH

The study aims to ascertain both in vivo and in vitro rewards of EXD.

MATERIALS AND METHODS

EXD is composed of Curculiginis Rhizoma, Epimedii Folium, Morindae Officinalis, Angelicae Sinensis, Anemarrhenae Rhizoma, and Phellodendri Chinensis Cortex. UPLC/MS analysis was used to investigate the components of EXD. Using a POF model created by administering cisplatin to rats intraperitoneally, the pharmacodynamic effects of EXD were investigated. Three dose groups of EXD were garaged into rats: high (15.6 g/kg), medium (7.8 g/kg), and low (3.9 g/kg). By using a vaginal smear, the impact of EXD on the rat estrous cycle was evaluated. An ELISA test was used to measure the anti-Mullerian hormone (AMH), estradiol (E2), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) levels in the serum of rats. By using HE stains, pathological alterations in the ovaries may be seen. MDA and SOD levels in ovarian samples were used to measure the degree of ovarian oxidation. TUNEL labeling of ovarian sections was used to find apoptosis levels. By using ATP, energy production was evaluated. The relative expression of proteins connected to aging and the RAGE pathway was assessed using Western blot. Then, using H₂O₂, a model of senescent human ovarian granulosa cells (KGN) was created in vitro. The impact of EXD and H₂O₂ on cellular senescence was discovered using-galactosidase staining. Cell apoptosis levels were found using PI/Hoechest33342. By using DCFH-DA, intracellular ROS was examined. MDA and SOD concentrations were used to measure the degree of cellular oxidation. RAGE-related mRNA and protein expression were evaluated using RT-qPCR and western blotting.

RESULTS

Using UPLC/MS analysis, 39 chemicals in EXD were found. Rats' estrous cycles were enhanced by EXD, which increased ovarian index and follicle count and reduced the proportion of atretic follicles in the rats. EXD reduced LH and FSH output while restoring AMH and E2 secretion. In ovarian tissues, EXD reduced the amount of apoptosis and MDA while raising SOD activity and ATP levels. The protein levels of p16, p21, p53, and Lamin A/C were among the senescence-related proteins that EXD lowered, along with the levels of RAGE, PI3K, BAX, and CASPASE 3. Anti-apoptotic protein BCL-2 was also raised in the RAGE pathway. Senescence, apoptosis, ROS, and MDA levels in the KGN cells were lowered in vitro by EXD. Additionally, EXD increased the anti-apoptotic potential by changing the expression of CAT, SOD2, and SIRT1. RAGE, BAX, BCL-2, CASPASE 3, and p38 expression levels were altered by EXD, enhancing its anti-apoptotic capability.

CONCLUSION

EXD boosted the ovary's antioxidant and anti-apoptotic capabilities while enhancing the estrous cycle and hormone output. These findings strongly suggested that EXD may contribute to the alleviation of POF and ovarian granulosa cells senescence.

CircEML1 facilitates the steroid synthesis in follicular granulosa cells of chicken through sponging gga-miR-449a to release IGF2BP3 expression

Non-coding RNAs (ncRNAs) induced competing endogenous RNAs (ceRNA) play crucial roles in various biological process by regulating target gene expression. However, the studies of ceRNA networks in the regulation of ovarian ovulation processing of chicken remains deficient compared to that in mammals. Our present study revealed that circEML1 was differential expressed in hen's ovarian tissues at different ages (15 W/20 W/30 W/68 W) and identified as a loop structure from EML1 pre-mRNA, which promoted the expressions of CYP19A1/StAR and E2/P4 secretion in follicular granulosa cells (GCs). Furthermore, circEML1 could serve as a sponge of gga-miR-449a and also found that IGF2BP3 was targeted by gga-miR-449a to co-participate in the steroidogenesis, which possibly act the regulatory role via mTOR/p38MAPK pathways. Meanwhile, in the rescue experiment, gga-miR-449a could reverse the promoting role of circEML1 to IGF2BP3 and steroidogenesis. Eventually, this study suggested that circEML1/gga-miR-449a/IGF2BP3 axis exerted an important role in the steroidogenesis in GCs of chicken.

MiR-34a-5p promotes autophagy and apoptosis of ovarian granulosa cells via the Hippo-YAP signaling pathway by targeting LEF1 in chicken

Follicular atresia is a natural physiological phenomenon in poultry reproduction. It is well known that follicular atresia is caused by both autophagy and apoptosis of granulosa cells. In current experiment, we evaluated the function of miR-34a-5p on autophagy and apoptosis in chicken follicular atresia. First, the follicular atresia model of chicken was successfully constructed by subcutaneous injection of tamoxifen (TMX), and found the expression of miR-34a-5p in the atresia follicles obviously increased. Then, we confirmed that miR-34a-5p accelerates autophagy and apoptosis of chicken granulose cells in vitro, and miR-34a-5p could induce apoptosis by mediating autophagy. Mechanistically, lymphoid enhancer binding factor 1 (LEF1) was deemed as a target gene for miR-34a-5p. On the contrary, LEF1 overexpression attenuated the autophagy and apoptosis of chicken granular cells. In addition, it was confirmed that the miR-34a-5p/LEF1 axis plays a regulatory role in chicken granulosa cells by mediating the Hippo-YAP signaling pathway. Taken together, this study demonstrated that miR-34a-5p contributes to autophagy and apoptosis of chicken follicular granulosa cells by targeting LEF1 to mediate the Hippo-YAP signaling pathway.

Identification of differentially expressed microRNAs in ovulatory and subordinate follicles in Dazu black goats

How multiple ovulations happen in prolific goats is still unknown even though studies on ovarian physiology and folliculogenesis have made extensive progress. MicroRNAs (miRNAs) are a class of endogenous regulatory factors and regulate structural gene expression mainly at the post-transcriptional level. In this study, in the follicular phase, six large follicles were collected from prolific Dazu black goat and used to generate RNA libraries for RNA sequencing. Based on the litter size and average number of ovulatory follicles in Dazu black goats, the largest three follicles were sorted as ovulatory follicles, and the remaining as subordinate ones. In total, 418 known miRNAs and 110 novel miRNAs were found, and the expression of six randomly selected miRNAs was validated by quantitative PCR analysis. Nine miRNAs were differently expressed between the ovulatory and subordinate follicles (p < 0.01). Chi-miR-582-5p, novel-130, chi-miR-214-3p, and chi-miR-500-5p were upregulated in the ovulatory group, and chi-miR-383, chi-miR-130b-5p, chi-miR-92a-3p, chi-miR-125b-5p, and novel-9 were downregulated in the same group. Chi-miR-130b-5p and chi-miR-214-3p were predicted to target at LHR (XM_013967581.1), GDF9 (NM_001285708.1), BMP15 (NM_001285588.1), and CYP19A1 (XM_013967046.1). In conclusion, nine miRNAs were differently expressed between ovulatory and subordinate follicles, and chi-miR-130b-5p and chi-miR-214-3p were predicted to regulate the expression of genes involved in gonadotropin hormone signaling and oocyte-derived growth factors. Additional studies are needed to confirm these findings.

Negative effects of heat stress on ovarian tissue in female rabbit

Numerous studies have highlighted the role of miRNA in the deformation and necrosis of cells of ovarian tissue caused by heat stress (HS), which ultimately affects ovarian function. Although the role of small RNAs has been investigated in alterations in ovarian tissue functioning in response to HS, the expression profile of ovarian miRNA has been explored to a lesser extent. In this study, female rabbits were subject to HS treatment by using electrical heater. The current work demonstrated that HS could significantly change physiological performance of female rabbits including body weight, rectal temperature and relative ovary weight, and significantly reduce serum IL-2, IL-8, CAT, and GSH-Px concentrations by enzyme-linked immunosorbent assay (ELISA) technique. As a result, an increase in apoptosis in ovarian cells, as well as unhealthy follicles, were observed by Hematoxylin-eosin (HE) and TUNEL staining. Additionally, small RNA-seq revealed changes in the miRNA expression profile of rabbit ovaries under HS. Five hundred fourteen miRNAs were obtained including known miRNAs 442 and novel miRNAs 72. Among these miRNAs, 23 miRNAs were significantly expressed under HS. Eleven differentially expressed miRNAs (DE miRNAs) and 9 their predicted targets were confirmed by qPCR, which were expected miRNA-mRNA negative regulation pattern. Among the DE miRNAs and targets, miR-141-39 may target COQ6, miR-449a-5p and miR-34c-5p may control RFC5 and RTN2 together, miR-449a-5p may target ACADVL, miR-34c-5p potentially targets Bcl-2 and miR-196b-5p potentially regulates CASK and HOXB6. Thus, the current work suggested the negative effects of HS on the ovarian tissue of female rabbits, and in conclusion these changes could be caused by decreased serum IL-2, IL-8, CAT and GSH-Px levels, increased ovarian apoptosis, and changed the expression of miRNAs.

BMP6 Promotes the Secretion of 17 Beta-Estradiol and Progesterone in Goat Ovarian Granulosa Cells

The purpose of this study was to investigate the effects of BMP6 on the function of goat ovarian granulosa cells (GCs). The results showed that the exogenous addition of BMP6 did not affect the EdU-positive ratio of ovarian GCs and had no significant effect on the mRNA and protein expression levels of the proliferation-related gene PCNA (p > 0.05). Meanwhile, BMP6 had no significant effect on the cycle phase distribution of GCs but increased the mRNA expression of CDK4 (p < 0.05) and CCND1 (p < 0.01) and decreased the mRNA expression of CCNE1 (p < 0.01). Moreover, BMP6 had no significant effect on the apoptosis rate of GCs and did not affect the mRNA expression levels of apoptosis-related genes BAX, BCL2, and Caspase3 (p > 0.05). Importantly, BMP6 upregulated the secretion of 17 beta-estradiol (E2) and progesterone (P4) in ovarian GCs (p < 0.01). Further studies found that BMP6 inhibited the mRNA expression of 3β-HSD and steroid synthesis acute regulator (StAR) but significantly promoted the mRNA expression of the E2 synthesis rate-limiting enzyme CYP19A1 and the P4 synthesis rate-limiting enzyme CYP11A1 (p < 0.01). Taken together, these results showed that the exogenous addition of BMP6 did not affect the proliferation, cell cycle, and apoptosis of goat ovarian GCs but promoted the secretion of E2 and progesterone P4 in ovarian GCs by upregulating the mRNA expressions of CYP19A1 and CYP11A1.

PTEN expression in human cumulus cells is associated with embryo development competence

Embryo quality determines the success of in vitro fertilization and embryo transfer (IVF-ET) treatment. Biomarkers for the evaluation of embryo quality have some limitations. Apoptosis in cumulus cells (CCs) is important for ovarian function. PTEN (phosphatase and tensin homolog) is a well known tumour suppressor gene that functions as a mediator of apoptosis and is crucial for mammalian reproduction. In the present study, we analyzed the expression level of PTEN in human CCs and aimed to investigate its association with embryo developmental competence in IVF treatment cycles. The PTEN mRNA level in CCs was measured using real-time fluorescence quantitative PCR. The association of the differential expression of PTEN with embryo quality was analyzed. Our data showed that PTEN mRNA levels were significantly decreased in CCs surrounding mature oocytes compared with immature oocytes. Similar changes were found in the analysis of fertilization and blastocyst formation. The speculation that the measurement of PTEN mRNA levels in human CCs would provide a useful tool for selecting oocytes with greater chances to implant into the uterus needs to be further verified through single-embryo transfer in the future. The proapoptotic mechanism of PTEN in human reproduction needs to be further studied.

Lysophosphatidic Acid Alters The Expression of Apoptosis Related Genes and miR-22 in Cultured and Autotransplanted Ovaries

OBJECTIVE

The aim of this study was to evaluate the effect of lysophosphatidic acid (LPA) on the follicular development, incidence of cell death, and expressions of apoptosis related genes and miR-22 in transplanted ovaries.

MATERIALS AND METHODS

In this experimental study, three-week-old mice ovaries were cultured for 24 hours in the presence and absence of LPA, and we assessed cell survival and normal follicular rates in some of the cultured ovaries. The remaining cultured ovaries were autotransplanted in the presence and absence of LPA as four experimental groups (LPA-/LPA-, LPA-/LPA+, LPA+/LPA-, LPA+/LPA+). The follicular development, immunohistochemistry for BAX, and expressions of genes related to apoptosis and miR-22 by real time reverse transcription polymerase chain reaction (RTPCR) were studied at the first oestrous cycles in the recovered ovaries. Sera 17-β-oestradiol (E2) and progesterone (P4) levels were also assessed.

RESULTS

Both cell survival and normal follicular rates were significantly higher in cultured ovaries in the presence of LPA after 24 hours (P<0.05). There was an increase in follicular development in comparison with the intact control group in the four transplanted groups (P<0.05). The LPA+/LPA- group had significantly higher follicular development, a decline in BAX positive cells, and a decrease in pro-apoptotic gene expressions in parallel with enhanced expression of anti-apoptotic and miR-22 genes and higher levels of hormones compared with the non-treated and intact control groups (P<0.05).

CONCLUSION

LPA, as a survival factor, improves follicular development in transplanted ovaries by providing a balance between the anti- and pro-apoptotic genes in association with an increase in miR-22 expression.

MicroRNA-1253 Suppresses Cell Proliferation Migration and Invasion of Osteosarcoma by Targeting MMP9

Purpose:

MicroRNAs play an important role in osteosarcoma (OS) development and progress. Although miR-1253 was considered as a tumor-inhibitor in some cancers, it’s function in the OS is not clear.

Methods:

In our study, we examined the expression of miR-1253 in OS cells and osteoblast cells using quantitative real-time PCR. The proliferation of OS cells was measured by BrdU assay, and we performed transwell to detect migration and invasion of OS cells. Meanwhile, EMT proteins were tested by western blot. We used Bioinformatics to predict the target genes of miR-1253 and found out Matrix metalloproteinases9 (MMP9) was one of that. The direct combination between miR-1253 and MMP9 was verified by double luciferase reporting experiment. Quantitative real-time PCR and western blot were used to detect the expression of MMP9.

Results:

We found that the expression level of miR-1253 in OS cells was significantly lower than that in osteoblast cells. Overexpression of miR-1253 could significantly inhibit OS cell proliferation, migration, invasion and EMT. And then, MMP9 was predicted as a downstream target of miR-1253 by Bioinformatics analysis. Further experiments showed that miR-1253 could reduce the protein level of MMP9 by directly binding to the 3’-UTR of MMP9. Afterward, we performed a rescue experiment, in which both MMP9 and miR-1253 were overexpressed. Compared with the groups overexpressed miR-1253 alone, cell proliferation, migration and invasion in co-overexpression groups were improved.

Conclusions:

In summary, these results suggested that miR-1253 down-regulated in OS cells, and could suppress the proliferation, migration and invasion of OS cells. Its molecular regulatory mechanism was that inhibits the expression of the downstream target gene MMP9 by directly binding, thus affect OS cell functions. Therefore, miR-1253 has the potential to become a biomarker and therapeutic target for OS therapy.

Elevation of miR-302b prevents multiple myeloma cell growth and bone destruction by blocking DKK1 secretion

BACKGROUND

Myeloma bone disease (MBD) is a severe complication of multiple myeloma (MM) mainly due to an imbalance between enhanced osteoclast activity and reduced osteoblast function. Previous studies have demonstrated that miRNAs play a vital role in the osteogenic differentiation of mesenchymal stromal cells (MSCs) in MM. However, the value of miR‑302b in MBD remains to be further elucidated. The aim of this study is to explore the role of miR‑302b in the regulation of MBD osteogenic differentiation and evaluate the potential of a new therapeutic strategy for the clinical treatment of MBD.

METHOD

Our previous research demonstrated that MiR-302b belongs to the miR-302 cluster and is able to inhibit tumor growth and osteolysis in an orthotopic osteosarcoma xenograft tumor mouse model. In this study, we first transfected miR-302b mimics, miR-302b inhibitor, and miR-302b NC into MM1.S and RPMI8226 MM cells to detect the correlation between miR-302b expression in the pathological specimens and the clinicopathological features by qPCR, the target correlation between miR-302b and DKK1 by immunohistochemistry, qPCR and Western blot, and the correlation between miR-302b and the Wnt/β-catenin signaling pathway by Western blot. The effect of miR-302b on osteoblastogenesis was also studied in a subperiosteal tumorigenesis model of NOD/SCID nude mice.

RESULTS

We found that increased miR-302b suppressed cell proliferation and induced cell apoptosis in RPMI 8226 and MM1.S cells. TargetScan online bioinformatic analysis predicted that miR-302b is able to bind to 3'UTR of DKK1 mRNA. Target binding of miR-302b to DKK1 was demonstrated by dual-luciferase reporter assay, qPCR, Western blot and immunohistochemistry, indicating that miR-302b is able to degrade DKK1 in RPMI 8226 and MM1.S cells. The model of co-culturing MM cells with preosteoblast MC3T3-E1 cells showed that miR-302b inhibits MM-induced suppression of osteoblast differentiation. Western blotting showed that miR-302b promotes the Wnt/β-catenin signaling pathway in MM cells. Micro-CT and immunohistochemistry results showed that miR-302b suppresses myeloma bone destruction in vivo.

CONCLUSION

miR-302b is able to target DKK1 and promote the Wnt/β-catenin signaling pathway in MM.

miR-18b regulates the function of rabbit ovary granulosa cells

MicroRNAs (miRNAs) have been determined to participate in the process of oestradiol production. Generally, there are two pathways by which oestradiol levels change, one being the state of cells (i.e. the status of enzymes involved in the synthesis of hormones such as oestradiol) and the other being the number of cells that secrete oestradiol. It is known that oestrogens are the main steroids produced by granulosa cells (GCs) of mature ovarian follicles. In this study we explored the function of miR-18b in rabbit GCs by overexpressing or inhibiting its activity. We found that miR-18b silencing promoted the secretion of oestradiol by significantly affecting the expression of steroidogenesis-related genes. Thus, miR-18b may act as a negative regulator of the production of enzymes related to oestradiol synthesis and affect oestradiol production. Furthermore, the effects of miR-18b on the proliferation, cell cycle and apoptosis of GCs were investigated using a cell counting kit (CCK-8) proliferation assay, detection of annexin V-fluorescein isothiocyanate apoptosis, flow cytometry and quantitative polymerase chain reaction. The results showed that miR-18b upregulated GC apoptosis (miR-18b overexpression decreases cell growth and stimulates apoptosis). These findings suggest that miR-18b and the oestrogen receptor 1 (ESR1) gene may be attractive targets to further explore the molecular regulation of GCs. The miR-18b may also explain, in part, the abnormal folliculogenesis in mammals caused by conditions such as polycystic ovary syndrome, primary ovarian insufficiency, and others.

Research on polycystic ovary syndrome: a bibliometric analysis from 2009 to 2019

Polycystic ovary syndrome (PCOS) is a common reproductive and endocrine disease. However, there have not been any bibliometric studies on the latest scientific results and research trends of PCOS. This study aimed to review the state of research in PCOS worldwide. Publications on PCOS from 2009 to 2019 were identified and evaluated from the database Web of Science. A total of 7814 articles were retrieved. Shanghai Jiao Tong University published the most articles, with 218 publications. Gynecol Endocrinol had the greatest number of publications (n = 541). J Clin Endocr Metab was cited the most, with a total of 32,207 times. An article written by March et al. in 2010 had the most global citations (737 times) and local citations (463 times). From 2009 to 2019, the number of PCOS global publications gradually increased. Gynecol Endocrinol and Endocr Metab were popular journals for PCOS research. Research trends gradually shifted from treatment and methodology to genetics and basic research. The terms 'microrna,' 'rt qpcr,' 'lncrna,' and 'histological examination' may be hotspots that should be focused on in PCOS research.

PTEN Expression in Human Granulosa Cells Is Associated with Ovarian Responses and Clinical Outcomes in IVF

The ovarian reserve determines the success of in vitro fertilization (IVF) and embryo transfer treatment. It predicts the ovarian response in controlled ovarian hyperstimulation cycles. Apoptosis in granulosa cells surrounding oocytes is important for ovarian function and has been closely associated with follicular atresia. PTEN (encoding phosphatase and tensin homolog) is a well-known tumor suppressor gene that functions as a mediator of apoptosis and is crucial for mammal reproduction. In the present study, we analyzed the expression level of PTEN in human granulosa cells and aimed to investigate its association with the ovarian response and clinical outcomes in IVF. Apoptosis in granulosa cells were analyzed using Annexin V-Allophycocyanin staining after PTEN short hairpin RNA lentivirus transfection. Real-time fluorescent quantitative PCR analysis showed that the PTEN transcript level was significantly higher in poor responders and significantly lower in high responders, compared with that in normal responders. However, PTEN expression in the pregnancy group decreased slightly, but not significantly, compared with that in the non-pregnancy group. The apoptosis rate of granulosa cells declined significantly after 24-h transfection of the PTEN-shRNA lentivirus. These results suggest a fundamental role of PTEN in the regulation of follicular development, and that it might be involved in the pathogenesis of follicular dysplasia and ovarian dysfunction.

Dingkun Pill replenishes diminished ovarian reserve through the PI3K/AKT/mTOR signaling pathway in TWP-induced mice

ETHNOPHARMACOLOGICAL RELEVANCE

Diminished ovarian reserve (DOR) can lead to poor fertility and shorten the reproductive lifespan of females. The Dingkun Pill (DKP), a traditional Chinese-patented medication, has been an integral part of traditional Chinese medicinal treatment for the management of gynecological diseases for centuries. Relevant clinical studies have shown that DKP is able to protect against DOR, however, its mechanism of action is not yet fully elucidated.

STUDY GOALS

This study was conducted with the aim of exploring the impact of tripterygium wilfordii polyglycosidium (TWP) on the PI3K/AKT/mTOR pathway in the context of the pathophysiology of DOR and the mechanism of action of DKP.

MATERIALS AND METHODS

Eighty female balb/c mice with regular estrous cycles were assigned to Blank, Model, DKP and hormone replacement therapy (HRT) groups in a random manner. With the exception of the Blank group, mice in the other groups were exposed to 40 mg/kg/d TWP suspension for 30 days to DOR induction. Following this, either DKP or hormones were orally administrated to determine their effect on disease progression. During the experiment, changes in body weight and the estrous cycles of the mice were observed. Post treatment, serum sample anti-mullerian hormone (AMH), estradiol (E₂), luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels were quantified using enzyme-linked immunosorbent assay (ELISA). The mice were then sacrificed in order to harvest their ovaries for hematoxylin and eosin (HE) staining. This process allowed for the assessment of ovarian morphology and follicular quantification. Apoptotic ovarian cells of the ovary were assessed using TUNEL technique, while Caspase-3 and Cytochrome C (Cyt C) expressions of the ovary were examined through immunohistochemistry (IHC). Western blotting analysis was used to quantify levels of Bax, Bcl-2, Caspase-3, Cyt C, mTOR, P-mTOR, AKT, P-AKT, P-PI3K and PI3K proteins, while mRNA levels of Bax, Bcl-2, PI3K, AKT and mTOR were measured in ovarian tissue using RT-PCR.

RESULTS

The findings revealed that DKP was able to improve levels of serum hormones and promote the recovery of the estrous cycle. DKP augmented the total amount of primordial follicles while reducing the number of follicles that were atretic follicles. The apoptosis index of growing follicles and Bax, Cyt C and Caspase-3 expressions decreased, while the Bcl-2: Bax ratio increased. DKP suppressed levels of phosphorylation and the mRNA expressions of mTOR, AKT and PI3K.

CONCLUSIONS

It was demonstrated that DKP was able to increase ovarian reserves through inhibition of the PI3K/AKT/mTOR signaling pathway, which lead to the suppression of primordial follicle activity and a reduction in levels of apoptosis of early growing follicles. This highlights its potentially beneficial role for the treatment of DOR.

MicroRNA-181a promotes follicular granulosa cell apoptosis via sphingosine-1-phosphate receptor 1 expression downregulation†

Oxidative stress induces granulosa cell (GC) apoptosis and subsequent follicular atresia. Since our previous studies indicate that microRNA-181a (miR-181a) expression is increased in GCs undergoing apoptosis, the present study was designed to define the relationship between exposure to oxidative stressors in GCs and changes in miR-181a expression and function. To achieve this, we employed an H2O2-induced in vitro model and a 3-nitropropionic acid-induced in vivo model of ovarian oxidative stress. We demonstrated that in vitro miR-181a overexpression promoted GC apoptosis in a dose-dependent manner; sphingosine-1-phosphate (S1P) significantly reversed both H2O2-induced and miR-181a-induced apoptosis in GCs. Moreover, we identified sphingosine-1-phosphate receptor 1 (S1PR1), a critical receptor of S1P, as a novel target of miR-181a in GCs. MicroRNA-181a induced GC apoptosis by repressing S1PR1 expression in vitro. Importantly, increased miR-181a expression and decreased S1PR1 expression were detected in the in vivo ovarian oxidative stress model by Western blot analysis and immunohistochemistry. Furthermore, we found similar expression patterns of miR-181a and S1PR1 in GCs from patients with premature ovarian insufficiency. In conclusion, our results suggest that miR-181a directly suppresses expression of S1PR1, which has critical roles in mediating oxidative stress-induced GC apoptosis both in vitro and in vivo.

Identification of the Key microRNAs and miRNA-mRNA Interaction Networks during the Ovarian Development of Hens

It is well-known that multiple functional miRNAs are found in mammals' ovaries, which are linked not only to ovarian development, but also to maturation and apoptosis. However, there is still a lack of knowledge regarding the role of miRNAs in the hen ovary. In the present study, we analyzed the miRNA sequencing libraries of ovaries at the four different developmental stages of hens (15, 20, 30, and 68 W) and a total of 677 known miRNAs and 61 novel miRNAs were identified. In total, 209 of them were differently expressed miRNAs (DE miRNAs) obtained from comparisons of the four stages, including 84 upregulated and 125 downregulated DE miRNAs. Furthermore, the five key DE miRNAs gga-miR-2954, gga-miR-6634-5p, gga-miR-449b-5p, gga-miR-449c-3p, and gga-miR449c-5p were screened using an analysis of the miRNA-mRNA interaction network and functional enrichment annotated in seven significantly enriched pathways, such as endocytosis, lysine degradation, the biosynthesis of amino acids, and the MAPK signaling pathway, which may primarily participate in cell differentiation and proliferation, steroid hormone biosynthesis, and angiogenesis by targeting the related genes. For instance, gga-miR-449 family members were predicted to target 15 genes, including TGFB1, TPM1, TPM3, and CAMKB2, which were reported to regulate follicular growth, selection, and the ovulatory cycle. Taken together, our results illustrate the ovarian miRNA profiles of the four classic developmental stages of hens and highlight the significant role of miRNAs in ovarian development and functions. However, in-depth research needs to be carried out to validate the potential functional miRNAs found in this study.

miRNA-21-3p targeting of FGF2 suppresses autophagy of bovine ovarian granulosa cells through AKT/mTOR pathway

It is widely thought that the main reason for ovarian follicular atresia is apoptosis of granulosa cells, however, accumulating evidence suggests that autophagy plays a role in the fate of granulosa cells. Although epigenetic regulation including miR-21-3p associated with autophagy process has been reported in many cancer types, nevertheless, the mechanism of miR-21-3p in bovine ovary is poorly understood. In the present study, bovine ovarian granulosa cells (BGCs) were used as a model to elucidate the autophagy and role of miR-21-3p in a cattle ovary. The results from gene expression and tagged autophagosomes showed the autophagy in BGCs and miR-21-3p was identified as an important miRNA regulating autophagy of BGCs. The current results indicated that FGF2 was a validated target of miR-21-3p in autophagy regulation of BGCs according to the results from FGF2 luciferase reporter assays and FGF2 overexpression (oe-FGF2) or small interference (si-FGF2). Transfection of miR-21-3p mimic and si-FGF2 plasmids resulted in decreasing phosphorylated AKT and mTOR, while transfection of miR-21-3p inhibitor and oe-FGF2 increased the phosphorylated level of AKT and mTOR in BGCs. These data indicate that regulation of miR-21-3p on BGCs autophagy through AKT/mTOR pathway. In summary, this study suggests that miR-21-3p targets FGF2 to inhibit BGCs autophagy by repressing AKT/mTOR signaling.

MicroRNAs regulate granulosa cells apoptosis and follicular development - A review

Objective

MicroRNAs (miRNAs) are the most abundant small RNAs. Approximately 2,000 annotated miRNAs genes have been found to be differentially expressed in ovarian follicles during the follicular development (FD). Many miRNAs exert their regulatory effects on the apoptosis of follicular granulosa cells (FGCs) and FD. However, accurate roles and mechanism of miRNAs regulating apoptosis of FGCs remain undetermined.

Methods

In this review, we summarized the regulatory role of each miRNA or miRNA cluster on FGCs apoptosis and FD on the bases of 41 academic articles retrieved from PubMed and web of science and other databases.

Results

Total of 30 miRNAs and 4 miRNAs clusters in 41 articles were reviewed and summarized in the present article. Twenty nine documents indicated explicitly that 24 miRNAs and miRNAs clusters in 29 articles promoted or induced FGCs apoptosis through their distinctive target genes. The remaining 10 miRNAs and miRNAs of 12 articles inhibited FGCs apoptosis. MiRNAs exerted modulation actions by at least 77 signal pathways during FGCs apoptosis and FD.

Conclusion

We concluded that miRNAs or miRNAs clusters could modulate the apoptosis of GCs (including follicular GCs, mural GCs and cumulus cells) by targeting their specific genes. A great majority of miRNAs show a promoting role on apoptosis of FGCs in mammals. But the accurate mechanism of miRNAs and miRNA clusters has not been well understood. It is necessary to ascertain clearly the role and mechanism of each miRNA or miRNA cluster in the future. Understanding precise functions and mechanisms of miRNAs in FGCs apoptosis and FD will be beneficial in developing new diagnostic and treatment strategies for treating infertility and ovarian diseases in humans and animals.

Grape Seed Procyanidin B2 Protects Porcine Ovarian Granulosa Cells against Oxidative Stress-Induced Apoptosis by Upregulating let-7a Expression

Oxidative stress is a causal factor and key promoter of all kinds of reproductive disorders related to granulosa cell (GC) apoptosis that acts by dysregulating the expression of related genes. Various studies have suggested that grape seed procyanidin B2 (GSPB2) may protect GCs from oxidative injury, though the underlying mechanisms are not fully understood. Therefore, whether the beneficial effects of GSPB2 are associated with microRNAs, which have been suggested to play a critical role in GC apoptosis by regulating the expression of protein-coding genes, was investigated in this study. The results showed that GSPB2 treatment protected GCs from a H₂O₂-induced apoptosis, as detected by an MTT assay and TUNEL staining, and increased let-7a expression in GCs. Furthermore, let-7a overexpression markedly increased cell viability and inhibited H₂O₂-induced GC apoptosis. Furthermore, the overexpression of let-7a reduced the upregulation of Fas expression in H₂O₂-treated GCs at the mRNA and protein levels. Dual-luciferase reporter assay results indicated that let-7a directly targets the Fas 3′-UTR. Furthermore, the overexpression of let-7a enhanced the protective effects of GSPB2 against GC apoptosis induced by H₂O₂. These results indicate that GSPB2 inhibits H₂O₂-induced apoptosis of GCs, possibly through the upregulation of let-7a.

CircINHA resists granulosa cell apoptosis by upregulating CTGF as a ceRNA of miR-10a-5p in pig ovarian follicles

Mammalian ovarian follicular atresia is a complex and fine-regulated biological process with active involvement of connective tissue growth factor (CTGF). The emergence of studies of endogenous non-coding RNAs has raised a new aspect for exploration of the regulatory mechanisms involved in follicular atresia. Here, we aimed to illustrate a circRNA involved in the CTGF regulatory pathway during the apoptosis and follicular atresia of pig granulosa cells (GCs). We first detected a decreased expression pattern of CTGF during follicular atresia using IHC, FISH and qRT-PCR and confirmed the anti-apoptosis effect of CTGF in GCs in vitro by CTGF siRNA knockdown. Then, we used a dual luciferase activity assay to demonstrate CTGF as a direct functional target of miR-10a-5p, which was upregulated in atresic follicles and promoted the apoptosis of GCs in vitro. The negative effect of miR-10a-5p on GC viability was confirmed by cell cycle assays, cell proliferation/apoptosis assays and the WB detection of marker proteins. More importantly, we identified a novel circRNA, termed circINHA, that was downregulated during atresia in ovarian follicles, and we confirmed a direct interaction between miR-10a-5p and circINHA. Finally, we demonstrated that circINHA promoted GCs proliferation and inhibited GCs apoptosis via CTGF as a competing endogenous RNA (ceRNA) that directly bound to miR-10a-5p. Taken together, this study provides evidence for the circINHA/miR-10a-5p/CTGF regulatory pathway in follicular GC apoptosis and provides novel insights into the role of circRNAs in the modulation of ovarian physiological functions.

Transcriptome analysis of ovary in relatively greater and lesser egg producing Jinghai Yellow Chicken

Egg production is determined by the function of ovary and is regulated by the hypothalamic-pituitary-ovary axis. The mechanism by which the ovary regulates egg production, however, is still poorly understood. The purpose of this study is to compare the transcriptome difference in ovary of relatively greater and lesser egg producing chickens, and to screen candidate genes related to egg production. A RNA sequencing was performed to analyze and compare the mRNA in ovarian tissues of relatively greater and lesser egg producing chickens. A total of 4 431 new genes expressed in the chicken ovary were mined. There were 305 differentially expressed genes (DEGs) identified between the relatively greater and lesser egg producing hens. Gene ontology analysis identified five candidate genes related to egg production, including ZP2, WNT4, AMH, IGF1, and CYP17A1 genes. Tissue expression profiles indicated these five candidate genes were highly expressed in chicken ovarian tissues, indicating a potential role in regulating chicken ovarian function and egg production. The KEGG analysis indicated the neuroactive ligand-receptor interaction pathway might have an important function in regulation of egg production. In addition, four known pathways related to reproduction were detected, including the calcium signaling, wnt signaling pathway, focal adhesion, and cytokine-cytokine receptor interaction pathways. Results of the present study indicate gene expression differences in the ovarian tissues of relatively greater and lesser egg producing chickens, and identified five important candidate genes related to egg production, which provided a theoretical basis for improving egg production of Jinghai Yellow Chickens.

The role of MiRNA in polycystic ovary syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder in reproductive-aged women. Clinical manifestations include hyperandrogenism, chronic anovulation, polycystic ovaries and being frequently accompanied by insulin resistance (IR) and obesity. MicroRNAs (miRNAs) are short non-coding RNAs which are involved in the regulation of gene expression at the post-transcriptional level. Altered miRNAs levels have been showed to be associated with a variety of diseases including diabetes, endometriosis and cancer. In recent years, more and more evidence suggests abnormal expression of miRNAs are detected in granulosa cells, theca cells, adipose tissue, follicular fluid, serum and peripheral blood leukocytes of women with PCOS and display vital role in the occurrence and development of PCOS. This will shed light on new strategies for the diagnosis and treatment of this syndrome. In this paper, we will review the recent research on miRNAs with respect to PCOS.

MicroRNA-205 affects mouse granulosa cell apoptosis and estradiol synthesis by targeting CREB1

MicroRNA-205 (miR-205) is involved in various physiological and pathological processes, but its biological function in follicular atresia remains unclear. In this study, we investigated miR-205 expression in mouse granulosa cells (mGCs) and analyzed its functions in primary mGCs by performing a series of in vitro experiments. Quantitative real-time polymerase chain reaction showed that miR-205 expression was significantly higher in early atretic follicles and progressively atretic follicles than in healthy follicles. miR-205 overexpression in mGCs significantly promoted apoptosis and caspase-3/9 activities, as well as inhibited estrogen (E2) release and cytochrome P450 family 19 subfamily A polypeptide 1 (CYP19A1, a key gene in E2 production) expression. Bioinformatics and luciferase reporter assays revealed that the gene encoding cyclic AMP response element (CRE)-binding protein 1 (CREB1) was a direct target of miR-205 in mGCs. CREB1 upregulation partially rescued the effects of miR-205 on apoptosis, caspase-3/9 activities, E2 production, and CYP19A1 expression on mGCs. These results indicate that miR-205 might play an important role in ovarian follicular development and provide new insights into follicular atresia.

Suppression of miR-1197-3p attenuates H2O2-induced apoptosis of goat luteinized granulosa cells via targeting PPARGC1A

Peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PPARGC1A) acts as a powerful coactivator of many transcriptional factors that relate to granulosa cell (GC) apoptosis. In this study, the miRNAs mediating goat follicular atresia and luteinized granulosa cell (LGC) apoptosis induced by hydrogen peroxide (H₂O₂) via PPARGC1A were investigated. Our results showed that miR-1197-3p targeted PPARGC1A was predicted by bioinformatics algorithm and verified by luciferase reporter assay. In addition, miR-1197-3p promoted goat LGC apoptosis via PPARGC1A through mitochondrial-dependent apoptosis pathway, and these effects could be restored by PPARGC1A overexpression. Moreover, H₂O₂-induced LGC apoptosis significantly upregulated miR-1197-3p expression and downregulated PPARGC1A level. Pretreatment of miR-1197-3p inhibitor alleviated LGC apoptosis induced by 400 μM H₂O₂ for 12 h, and preserved the mitochondrial membrane potential by increasing PPARGC1A expression. In conclusion, miR-1197-3p might act as an essential regulator of goat LGC apoptosis potentially via the mitochondrial-dependent apoptosis pathway by targeting PPARGC1A.

Integrated Analysis of mRNA and miRNA Expression Profiles in the Ovary of Oryctolagus cuniculus in Response to Gonadotrophic Stimulation

Molecular mechanisms responsible for gonadotrophic control of ovarian follicle development and ovulation have not been fully delineated. In this study, prepubertal female rabbits were subjected to a combined PMSG/hCG treatment for the induction of follicle maturation and ovulation. Ovaries of 6 does at different time points during gonadotrophic stimulation were collected for histomorphological examination and genome-wide analysis of miRNA and mRNA transcriptomes, and the plasma were separated for detecting melatonin (MT), prostaglandin E₂ (PGE₂), estradiol (E₂), and progesterone (P₄) levels. The results suggested that PMSG promoted the development of the reproductive tract by decreasing plasma levels of E₂ and slightly increasing those of MT and PGE₂ and that hCG induced ovulation and corpus luteum formation by significantly increasing MT, PGE₂, and P₄ levels. At the transcriptomic level, a total of 1,122 differentially expressed genes (DEGs) and 12 DE miRNAs were identified using three-group comparisons. Meanwhile, pairwise comparisons revealed that 279 and 103 genes as well as 36 and 20 miRNAs were up- and down-regulated during PMSG-stimulated follicle development while 11 and 5 genes as well as 33 and 16 miRNAs were up- and down-regulated during hCG-induced luteinization. KEGG enrichment analysis of the DEGs derived from both three-group- and two-group comparisons as well as the predicted target genes of DE miRNAs highlighted the crucial roles of pathways involving tissue remodeling, energy metabolism, and regulation of cellular functions in mediating gonadotrophin-induced follicle maturation. Specifically, 3 genes including the matrix metallopeptidase 13 (MMP13), protein phosphatase 1 regulatory subunit 3C (PPP1R3C), and solute carrier family 2 member 12 (SLC2A12), together with 2 miRNAs including the miR-205-1 and miR-34c, were predicted to be the promising downstream targets of both PMSG and hCG. Significantly, the miRNA-mRNA interaction pairs containing top 10 up- and down-regulated mRNAs/miRNAs upon PMSG/hCG stimulation were established, and so were those involved in the PI3K-Akt, ECM-receptor interaction, and focal adhesion pathways during PMSG-induced follicle maturation. Finally, qRT-PCR analysis confirmed the results from RNA-Seq and Small RNA-Seq. Our work may contribute to a better understanding of the regulatory mechanisms of gonadotrophins on ovarian follicle development and ovulation.

The Role of microRNAs in Ovarian Granulosa Cells in Health and Disease

The granulosa cell (GC) is a critical somatic component of the ovary. It is essential for follicle development by supporting the developing oocyte, proliferating and producing sex steroids and disparate growth factors. Knowledge of the GC's function in normal ovarian development and function, and reproductive disorders, such as polycystic ovary syndrome (PCOS) and premature ovarian failure (POF), is largely acquired through clinical studies and preclinical animal models. Recently, microRNAs have been recognized to play important regulatory roles in GC pathophysiology. Here, we examine the recent findings on the role of miRNAs in the GC, including four related signaling pathways (Transforming growth factor-β pathway, Follicle-stimulating hormones pathway, hormone-related miRNAs, Apoptosis-related pathways) and relevant diseases. Therefore, miRNAs appear to be important regulators of GC function in both physiological and pathological conditions. We suggest that targeting specific microRNAs is a potential therapeutic option for treating ovary-related diseases, such as PCOS, POF, and GCT.

Mathematical model to study the aging of the human follicle according to the telomerase activity

The aim of this work is to study the aging rate at which human follicles reach the preovulatory state. To this end, both telomere length and telomerase activity effects on granulosa cells (GCs) aging has been studied. GCs are somatic cells which determine the development of the oocyte. A human preantral follicle takes approximately 85 days to achieve the preovulatory size, going through several stages (Gougeon, 1996). The telomere length of GCs of each class of follicles, during folliculogenesis, are modelled using a chemical master equation formalism similar to the one in Wesch et al. (2016). Seven differential ordinary systems of equations, corresponding to seven stages of the follicule maturation, concatenated in time, are considered. The mitotic and death rates are approximated by using the mean number of GCs in each class of follicles and the time they remain on each stage. The influence of different telomerase activity rates and the telomere shortening of the preovulatory follicle is studied. Some cases of infertility are associated with low levels of telomerase activity and short telomeres in GCs. The method aims at understanding how low levels of telomerase activity in preovulatory stages lead to the accumulation of aged GCs. In the case of higher telomerase activities, the mathematical model predicts a more juvenile outcome in preovulatory follicles. Juvenile GCs, could be critical for embryo development if the oocyte were fertilized, since GCs, transformed in corpus luteum, must divide and increase their size (Alila and Hansel, 1984) to sustain early pregnancy (Csapo et al., 1972).

Programmed cell death in the human ovary

During a woman's reproductive life, only about 400 primordial follicles will develop into a preovulatory follicle and undergo ovulation, releasing an oocyte available for fertilization. The process of formation and selection of these follicles is complex and involves a multistep process characterized by a balance between survival and death of the oocytes and the surrounding follicular cells. Although the mechanisms underlying such process are not completely clarified yet, it is common idea that they can occur through various types of programmed cellular death (PCD). Since atresia is the principal destiny of the ovarian follicles, it is relevant to understand how this process takes place and how it is regulated. In this review, after a summary description of folliculogenesis in humans, the main mechanisms of atresia reported to occur during folliculogenesis from birth to adult age, in the human ovary and in other mammals when appropriate, are described.

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.

miR-1275 controls granulosa cell apoptosis and estradiol synthesis by impairing LRH-1/CYP19A1 axis

miR-1275 is one of the microRNAs (miRNAs) that are differentially expressed during follicular atresia in pig ovaries, as identified by a miRNA microarray assay in our previous study [1]. However, its functions in follicular atresia remain unknown. In this study, we showed that miR-1275 promotes early apoptosis of porcine granulosa cells (pGCs) and the initiation of follicular atresia, and inhibits E2 release and expression of CYP19A1, the key gene in E2 production. Bioinformatics and luciferase reporter assays revealed that liver receptor homolog (LRH)-1, not CYP19A1, is a direct functional target of miR-1275. In vitro overexpression and knockdown experiments showed that LRH-1 significantly repressed apoptosis and induced E2 secretion and CYP19A1 expression in pGCs. LRH-1, whose expression was regulated by miR-1275, prevented apoptosis in pGCs. Furthermore, luciferase and chromatin immunoprecipitation assays demonstrated that LRH-1 protein bound to the CYP19A1 promoter and increased its activity. Our findings suggest that miR-1275 attenuates LRH-1 expression by directly binding to its 3'UTR. This prevents the interaction of LRH-1 protein with the CYP19A1 promoter, represses E2 synthesis, promotes pGC apoptosis, and initiates follicular atresia in porcine ovaries.

Estrogen Effects on Wound Healing

Wound healing is a physiological process, involving three successive and overlapping phases—hemostasis/inflammation, proliferation, and remodeling—to maintain the integrity of skin after trauma, either by accident or by procedure. Any disruption or unbalanced distribution of these processes might result in abnormal wound healing. Many molecular and clinical data support the effects of estrogen on normal skin homeostasis and wound healing. Estrogen deficiency, for example in postmenopausal women, is detrimental to wound healing processes, notably inflammation and re-granulation, while exogenous estrogen treatment may reverse these effects. Understanding the role of estrogen on skin might provide further opportunities to develop estrogen-related therapy for assistance in wound healing.