MicroRNAs in ovarian follicular atresia and granulosa cell apoptosis

Comparative transcriptome profile analysis of granulosa cells from porcine ovarian follicles during early atresia

At various stages of ovarian follicular development, more than 99% of follicles will be eliminated through a degenerative process called atresia. The regulatory mechanisms of atresia have been elucidated to some extent, involving hormones, growth factors, cytokines, and other factors. However, the stimuli initiating atresia in follicular granulosa cells remain unknown. In this study, we isolated the granulosa cells from porcine ovarian follicles (3-5 mm diameter) divided into healthy follicles (HFs) and early atretic follicles (EAFs). We applied high-throughput RNA sequencing to identify and compare differentially expressed genes (DEGs) between HFs and EAFs. A total of 31,694 genes were detected, of which 21,806 were co-expressed in six samples, and 243 genes (p < 0.05; FDR < 0.05) were differentially expressed (DEGs), including 123 downregulated and 120 upregulated in EAFs. GO analysis highlighted hormone metabolism, plasma membrane localization, and transporter activity. The pathway analysis indicated that 51 DEGs, involved in steroidogenesis, cell adhesion molecules, and TGF-beta signaling pathways, were highly related to atresia. Additionally, the interaction network of DEGs (p < 0.01; FDR < 0.05) using STRING highlighted LHR, ACACB, and CXCR4 as central nodes. In summary, this transcriptome analysis enriched our knowledge of the shifted mechanisms in granulosa cells during early atresia and provided novel perspectives into the atresia initiation.

Deciphering the miRNA transcriptome of granulosa cells from dominant and subordinate follicles at first follicular wave in goat

In goats, most follicles in the ovaries will be atresia and only a few dominant follicles (DFs) may eventually mature and ovulate at a follicular wave. To investigate the potential microRNAs (miRNAs) that regulate the expression of genes associated with follicular dominance or atresia, small RNA sequencing was performed on granulosa cells of DF and subordinate follicle at the first follicular wave in goats. A total of 108 differentially expressed miRNAs were detected in the two types of follicle granulosa cells: 16 upregulated miRNAs and 92 downregulated miRNAs. Kyoto Encyclopedia of Genes and Genomes analysis of the target genes showed that TKTL1, LOC102187810, LOC102184409 and ALDOA are closely associated with follicle dominance and are involved in the pentose phosphate pathway. Furthermore, a coexpression network of miRNAs and follicular dominance-related genes was constructed. The qPCR results well correlated with the small RNA sequencing data. Our findings provide new insight for exploring the molecular mechanism of miRNAs in regulating follicular development in goats.

DNA methylation, but not microRNA expression, is affected by in vitro THC exposure in bovine granulosa cells

BACKGROUND

A global increase in cannabis use has led to questions about its effects on fertility. The rise in consumption amongst women of reproductive age is a growing concern, as this group is vulnerable in terms of reproductive health. Ample evidence suggests that the psychoactive component of cannabis, Δ9-Tetrahydrocannabinol (THC), interacts with the endocannabinoid system (ECS), that helps regulate mammalian reproduction. This study aimed to research the epigenetic effects of THC in bovine granulosa cells (GCs) by (1) investigating global DNA methylation via measuring 5-mC and 5-hmC levels; (2) measuring key methylation regulators, including the methylating enzymes DNMT1, DNMT3a, DNMT3b and the demethylases TDG and TET1/2/3; and (3) assessing fertility-associated miRNAs key in developmental competency, including miR-21, -155, -33b, -324 and -346.

METHODS

Bovine GCs were used as a translational model for reproductive toxicity in humans. To determine THC effects, GCs were isolated from Cumulus-Oocyte-Complexes (COCs) from bovine ovaries, cultured in vitro for 7 days, or until confluent, and cryopreserved at passage 1 (P1). For experimentation, cells were thawed, cultured until passage 2 (P2), serum restricted for 24-h and treated for 24-h in one of five groups: control, vehicle (1:1:18 ethanol: tween: saline) and three clinically relevant THC doses (0.032, 0.32 and 3.2 μM). Global methylation was assessed by measuring 5-mC and 5-hmC levels with flow cytometry. To assess mRNA and protein expression of methylation regulators and miRNA profiles, qPCR and Western Blotting were utilized. Shapiro-Wilk test was used to determine normality within datasets. One-way ANOVA was applied to determine statistical significance using GraphPad Prism 6.0.0.

RESULTS

Results indicate a significant decrease (p = 0.0435) in 5-mC levels following low THC exposure, while no changes were observed in 5-hmC levels. A significant increase in DNMT1 following high THC exposure at the RNA level (p < 0.05) and a significant increase following low THC exposure at the protein level (p = 0.0048) were also observed. No significant differences were observed in DNMT3a/3b, TDG, TET1/2/3 mRNAs or in any of the miRNAs analyzed.

CONCLUSIONS

This research suggests that THC mainly affects DNA methylation, but not miRNA profiles, ultimately altering gene expression and likely impairing oocyte competence, maturation, and fertilization potential.

Molecular and transcriptomic analysis of the ovary during laying and brooding stages in Zhedong white geese (Anser cygnoides domesticus)

1. This study investigates the molecular mechanisms affecting brooding in Zhedong white geese by examining differences in reproductive endocrine levels, ovarian histology and transcriptomics.2. Twenty 18-month-old Zhedong white geese were selected to examine their ovaries using histological, biochemical, molecular biological, and high-throughput sequencing techniques during the laying and brooding periods.3. The results showed that the number of atretic follicles and apoptotic cells in the ovaries increased significantly (p < 0.05), the levels of follicle-stimulating hormone, luteinising hormone, gonadotropin-releasing hormone and oestradiol decreased significantly (p < 0.05), and the level of prolactin increased significantly (p < 0.01) during the brooding stage.4. In broody geese, the expression of CASP3, CASP9, P53, BAX, and Cyt-c were considerably higher (p < 0.05), but BCL2 expression was significantly lower (p < 0.05).5. In ovarian tissues, 260 differentially expressed lncRNAs, 13 differentially expressed miRNA and 60 differentially expressed mRNA were all discovered using transcriptome sequencing analysis. Functional enrichment analysis revealed that the differentially expressed mRNA and non-coding RNA target genes were primarily involved in ECM-receptor interaction, cell adhesion, cardiac muscle contraction, mTOR signalling, and the calcium signalling pathway.6. In conclusion, follicular atrophy and apoptosis occurred in the ovaries and serum reproductive hormone levels were significantly changed during the brooding period of Zhedong white geese. COL3A1, COL1A2, GRIA1, RNF152, miR-192, and miR-194 may be important candidates for the regulation of brooding behaviour, with the mTOR signalling pathway playing a key role.

The influence of indole propionic acid on molecular markers of steroidogenesis, ER stress, and apoptosis in rat granulosa cells exposed to high glucose conditions

Hyperglycemia is known as one of the main causes of infertility in human societies. Indole propionic acid (IPA) is produced by intestinal microbiota and has antioxidant and anti-inflammatory properties. This study aims to investigate the effects of IPA on molecular indices of steroidogenesis, ER stress, and apoptosis induced by high glucose (HG) in granulosa cells. Primary GCs, isolated from ovarian follicles of Rats were cultured in 5 mM (control) and 30 mM (HG) of glucose and in the presence of 10 and 20 µM of IPA for 24 h. The cell viability was assessed by MTT. The gene expression of P450SCC, 3βHSD, CYP19A, BAX, BCL2, and STAR was evaluated by Real-Time PCR. Protein expression of ATF6, PERK, GRP78, and CHOP determined by western blot. Progesterone, estradiol, IL-1β, and TNF-α were measured by ELISA. HG decreased the viability, and expression of P450SCC, 3βHSD, CYP19A, BCL2, STAR, and increased BAX. 10 and 20 µM of IPA increased cell viability, expression of P450SCC, 3βHSD, CYP19A, BCL2 and STAR and decreased BAX compared to the HG group. The expression of ATF6, PERK, GRP78, and CHOP proteins increased by HG and IPA decreased the expression of these proteins compared to the HG group. Also, HG decreased progesterone and estradiol levels and increased IL-1β and TNF-α. IPA significantly increased progesterone and estradiol and decreased IL-1β and TNF-α compared to the HG group. IPA can improve the side effects of HG in GCs of rats, as responsible cells for fertility, by improving steroidogenesis, regulation of ER-stress pathway, suppression of inflammation, and apoptosis.

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.

Extracellular vesicles secreted by cumulus cells contain microRNAs that are potential regulatory factors of mouse oocyte developmental competence

The role of cumulus cells (CCs) in the acquisition of oocyte developmental competence is not yet fully understood. In a previous study, we matured cumulus-denuded fully-grown mouse oocytes to metaphase II (MII) on a feeder layer of CCs (FL-CCs) isolated from developmentally competent (FL-SN-CCs) or incompetent (FL-NSN-CCs) SN (surrounded nucleolus) or NSN (not surrounding nucleolus) oocytes, respectively. We observed that oocytes cultured on the former could develop into blastocysts, while those matured on the latter arrested at the 2-cell stage. To investigate the CC factors contributing to oocyte developmental competence, here we focused on the CCs' release into the medium of extracellular vesicles (EVs) and on their miRNA content. We found that, during the 15-h transition to MII, both FL-SN-CCs and FL-NSN-CCs release EVs that can be detected, by confocal microscopy, inside the zona pellucida (ZP) or the ooplasm. The majority of EVs are <200 nm in size, which is compatible with their ability to cross the ZP. Next-generation sequencing of the miRNome of FL-SN-CC versus FL-NSN-CC EVs highlighted 74 differentially expressed miRNAs, with 43 up- and 31 down-regulated. Although most of these miRNAs do not have known roles in the ovary, in silico functional analysis showed that seven of these miRNAs regulate 71 target genes with specific roles in meiosis resumption (N = 24), follicle growth (N = 23), fertilization (N = 1), and the acquisition of oocyte developmental competence (N = 23). Overall, our results indicate CC EVs as emerging candidates of the CC-to-oocyte communication axis and uncover a group of miRNAs as potential regulatory factors.

Chicken ovarian follicular atresia: interaction network at organic, cellular, and molecular levels

Most of follicles undergo a degenerative process called follicular atresia. This process directly affects the egg production of laying hens and is regulated by external and internal factors. External factors primarily include nutrition and environmental factors. In follicular atresia, internal factors are predominantly regulated at 3 levels; organic, cellular and molecular levels. At the organic level, the hypothalamic-pituitary-ovary (HPO) axis plays an essential role in controlling follicular development. At the cellular level, gonadotropins and cytokines, as well as estrogens, bind to their receptors and activate different signaling pathways, thereby suppressing follicular atresia. By contrast, oxidative stress induces follicular atresia by increasing ROS levels. At the molecular level, granulosa cell (GC) apoptosis is not the only factor triggering follicular atresia. Autophagy is also known to give rise to atresia. Epigenetics also plays a pivotal role in regulating gene expression in processes that seem to be related to follicular atresia, such as apoptosis, autophagy, proliferation, and steroidogenesis. Among these processes, the miRNA regulation mechanism is well-studied. The current review focuses on factors that regulate follicular atresia at organic, cellular and molecular levels and evaluates the interaction network among these levels. Additionally, this review summarizes atretic follicle characteristics, in vitro modeling methods, and factors preventing follicular atresia in laying hens.

GATA4: Regulation of expression and functions in goat granulosa cells

GATA4 plays a pivotal role in the reproductive processes of mammals. However, the research on GATA4 in goat ovary is limited. This study aimed to study the expression and function of GATA4 in goat ovary. Utilizing real-time PCR and western blot analysis, we studied the expression and regulatory mechanisms of GATA4 in goat ovary and granulosa cells (GCs). We found that GATA4 was expressed in all follicle types in the goat ovary, with significantly higher levels in GCs of larger follicles (>3 mm) compared to those in smaller follicles (<3 mm). Additionally, we demonstrated that human chorionic gonadotrophin (hCG) induced GATA4 mRNA expression via the activation of PKA, MEK, p38 MAPK, PKC, and PI3K pathways in vitro. Our study also showed that hCG suppressed the levels of miR-200b and miR-429, which in turn directly target GATA4, thereby modulating the basal and hCG-induced expression of GATA4. Functionally, we examined the effect of siRNA-mediated GATA4 knockdown on cell proliferation and hormone secretion in goat GCs. Our results revealed that knockdown of GATA4, miR-200b, and miR-429 suppressed cell proliferation. Moreover, knockdown of GATA4 decreased estradiol and progesterone production by inhibiting the promoter activities of CYP11A1, CYP19A1, HSD3B, and StAR. Collectively, our findings suggest a critical involvement of GATA4 in regulating goat GC survival and steroidogenesis.

Aberrantly High FBXO31 Impairs Oocyte Quality in Premature Ovarian Insufficiency

Premature ovarian insufficiency (POI), which is defined as loss of ovarian function that occurs before the age of 40, causes menstrual disturbances, infertility, and diverse health problems in females. Despite the limited understanding of the molecular basis underlying POI pathology, we had previously demonstrated that the cooperation of miR-106a and FBXO31 plays a pivotal role in diminished ovarian reserve (DOR), with FBXO31 serving as a putative target of miR-106a. In this study, we found that FBXO31 is aberrantly expressed in granulosa cells of POI patients, leading to accumulated reactive oxygen species (ROS) and cell apoptosis via the p53/ROS pathway. Furthermore, our results demonstrated that high levels of FBXO31 in mouse ovaries impair oocyte quality. Our study revealed that FBXO31 may serve as a novel indicator and play a significant role in the etiology of POI.

Autophagy activity is increased in the cumulus cells of women with poor ovarian response

OBJECTIVE

To evaluate the autophagy status of cumulus cells (CCs) in women with poor ovarian response (POR).

MATERIALS AND METHODS

CCs were divided into normal ovarian response (NOR) group and POR group. The ultrastructure of autophagy was analyzed by transmission electron microscopy (NOR: n = 18, POR: n = 26). The mRNA and protein of autophagy markers were detected by Quantitative real-time polymerase chain reaction (NOR: n = 15, POR: n = 19) and Western blotting (NOR: n = 41, POR: n = 38), respectively.

RESULTS

Transmission electron microscopy demonstrated abundant autophagosomes and even autophagic death in the POR group. There were no differences in LC3 and P62 mRNA expression between the two groups (p > 0.05). The BCL2 mRNA expression was lower in the POR group (p < 0.05). Moreover, the LC3 II/I ratio and the P62 protein expression were significantly higher in the POR group (p < 0.05).

CONCLUSIONS

Autophagy in CCs of POR women is activated and the autophagic flux is blocked. The up-regulation of autophagy in CCs may be related to the pathogenesis of POR.

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.

Small extracellular vesicles in follicular fluids for predicting reproductive outcomes in assisted reproductive technology

BACKGROUND

Assisted reproductive technology accounts for an increasing proportion of infertility treatments, and assessments to predict clinical pregnancy outcomes are desired. Extracellular vesicles exist in follicular fluid, and small non coding RNAs in extracellular vesicles underline the possibility of reflecting pregnancy potential.

METHODS

Follicular fluid samples are collected from 20 ovarian follicles of 15 infertile patients undergoing assisted reproductive technology. Extracellular vesicles are isolated by serial centrifugation and small RNA sequencing is performed to investigate the profiles of microRNAs and P-element-induced wimpy testis-interacting RNAs.

RESULTS

Small extracellular vesicles with a size range of approximately 100 nm are successfully isolated, and the small non coding RNA profiles of pregnant samples (n = 8) are different from those of non-pregnant samples (n = 12). Fourteen dysregulated small non coding RNAs are selected to identify the independent candidates [mean read count >100, area under the curve >0.8]. Among them, we find that a specific combination of small non coding RNAs (miR-16-2-3p, miR-378a-3p, and miR-483-5p) can predict the pregnant samples more precisely using a receiver operating characteristics curves analysis (area under the curve: 0.96). Furthermore, even in the same patients, the three microRNAs are differentially expressed between pregnant and non-pregnant samples.

CONCLUSIONS

Our results demonstrate that small non coding RNAs derived from small extracellular vesicles in follicular fluid can be potential non-invasive biomarkers for predicting pregnancy, leading to their probable application in assisted reproductive technology. Further large-scale studies are required to validate the clinical usefulness of these small non coding RNAs.

miR-128-3p Regulates Follicular Granulosa Cell Proliferation and Apoptosis by Targeting the Growth Hormone Secretagogue Receptor

The proliferation and apoptosis of granulosa cells (GCs) affect follicle development and reproductive disorders, with microRNAs playing a crucial regulatory role. Previous studies have shown the differential expression of miR-128-3p at different stages of goat follicle development, which suggests its potential regulatory role in follicle development. In this study, through the Cell Counting Kit-8 assay, the EDU assay, flow cytometry, quantitative real-time polymerase chain reaction, Western blot, and the dual-luciferase reporter assay, we used immortal human ovarian granulosa tumor cell line (KGN) cells as materials to investigate the effects of miR-128-3p and its predicted target gene growth hormone secretagogue receptor (GHSR) on GC proliferation and apoptosis. The results show that overexpression of miR-128-3p inhibited the proliferation of KGN cells, promoted cell apoptosis, and suppressed the expression of proliferating cell nuclear antigen (PCNA) and B-cell lymphoma-2 (BCL2) while promoting that of Bcl-2 associated X protein (BAX). The dual-luciferase reporter assay revealed that miR-128-3p bound to the 3' untranslated region sequence of GHSR, which resulted in the inhibited expression of GHSR protein. Investigation of the effects of GHSR on GC proliferation and apoptosis revealed that GHSR overexpression promoted the expression of PCNA and BCL2, enhanced GC proliferation, and inhibited cell apoptosis, whereas the opposite effects were observed when GHSR expression was inhibited. In addition, miR-128-3p and GHSR can influence the expression of extracellular signal-regulated kinase 1/2 protein. In conclusion, miR-128-3p inhibits KGN cell proliferation and promotes cell apoptosis by downregulating the expression of the GHSR gene.

Bushen Tianjing Recipe inhibits human ovarian granulosa cell line KGN apoptosis induced by miR-23a through the regulation of the sirtuin family

ETHNOPHARMACOLOGICAL RELEVANCE

Bushen Tianjing Recipe (BTR) is a tonic-kidney formula of Traditional Chinese Medicine (TCM) with good therapeutic effects in clinical settings. It was mainly applied to inhibit the decrease of ovarian reserve function in patients. However, the anti-apoptosis mechanism of BTR remains unknown.

AIM OF THE STUDY

The formula of BTR is composed of prepared rehmannia root, debark peony root, carapax testudinis and asiatic cornelian cherry fruit. All four components contain the essences of nourishing yin and tonic-kidney. In the theory of TCM, the kidneys store the essence and are primarily responsible for reproduction and development. Hence, we speculated that BTR had some effect on women's reproductive system. In our research, rat serum contains BTR resolved into culture medium for incubation with miR-23a-induced KGN cells to test and determine our hypothesis.

MATERIALS AND METHODS

BTR was prepared by the traditional decoction method to collect concentrated liquids for oral administration to rats (15.00 g/kg) for 14 days. The group with miR-23a-induced KGN cells was selected as the positive control, while the mimic one was the control. Pro-apoptosis and anti-apoptosis biomarkers were detected and analyzed by western blot together with upstream transcription factors and intracellular apoptotic signal pathways.

RESULTS

The medium- and high-concentration of BRT greatly reduced the apoptosis of miR-23a-induced KGN cells both in mitochondria and cytoplasm. It showed the up-regulation of SIRT1 and SIRT3, the down-regulation of pro-apoptosis factor Bax and apoptotic-related proteins Caspase 3, 8, 9, and the reduction of phosphorylation of ERK1/2 and NF-κB. however, there was no consistency in the group with a low concentration of BTR, compared with those of other groups.

CONCLUSION

Our research verified that BTR had a positive effect on women's reproductive system under medium or high concentration, illuminated the intrinsic mechanism at molecular levels, and convinced its potential application values in clinical settings.

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.

Downregulation of homeobox A1 in human granulosa cells is involved in diminished ovarian reserve through promoting cell apoptosis and mitochondrial dysfunction

Granulosa cell apoptosis contributes to the occurrence of diminished ovarian reserve (DOR). HOXA1, belonging to the HOX gene family, is involved in regulating cancer cell apoptosis. However, whether HOXA1 participates in the granulosa cell apoptosis in DOR patients remains to be elucidated. In the current study, we demonstrated the differential transcriptomic landscape of granulosa cells in DOR patients compared to that in the controls and identified decreased expression of the HOXA1 gene. Meanwhile, we found that HOXA1 was a gonadotropin-response gene, in which FSH could promote its expression, whereas LH inhibited HOXA1 expression in human granulosa cells. CCK-8 assay, flow cytometry and TUNEL staining results showed that inhibition of endogenous HOXA1 expression promoted human granulosa cell apoptosis. Moreover, knockdown of HOXA1 increased Bax while reducing Bcl2 protein expression. Furthermore, we found a total of 947 differentially expressed genes (DEGs), including 426 upregulated genes and 521 downregulated genes using transcriptome sequencing technology. Enrichment analysis results showed that the DEGs were involved in apoptosis and mitochondrial function-related signaling pathways. Knockdown of HOXA1 impaired mitochondrial functions, exhibiting increased reactive oxygen species (ROS) and cytoplasmic Ca2+ levels, decreased mitochondrial membrane potential, ATP production and mitochondrial DNA (mtDNA) copy number, and abnormal mitochondrial cristae. Our findings demonstrated that aberrantly reduced HOXA1 expression induced granulosa cell apoptosis in DOR patients and impaired mitochondrial function, which highlighted the potential role of HOXA1 in the occurrence of DOR and provided new insight for the treatment of DOR.

Subtotal hysterectomy causes fewer long-term detrimental effects on ovary tissues than total hysterectomy

BACKGROUND

Hysterectomy is the basic surgical procedure of gynecological surgery. Traditionally, it is divided into total hysterectomy (TH) and subtotal hysterectomy (STH) according to the scope of surgery. The ovary is a dynamic organ appended with the uterus, and the uterus provides vascular supply to the developing ovary. However, the long-term impacts of TH and STH on ovary tissues need to be evaluated.

METHOD

In this study, rabbit models of different ranges of hysterectomy were successfully created. The estrous cycle of animals was determined by vaginal exfoliated cell smear 4 months after the operation. The apoptosis rate of ovarian cells in each group was determined by flow cytometry, and the morphology of ovarian tissue and granulosa cells in the control group, triangular hysterectomy group and total hysterectomy group were observed under microscope and electron microscope, respectively.

RESULTS

After total hysterectomy, the apoptotic events in ovarian tissues were significantly increased when compared to the sham and triangle hysterectomy group. Increased apoptosis was accompanied with the morphological changes and disrupted organelle structures in ovarian granulosa cells. The follicles in the ovarian tissue were dysfunctional and immature, with more atretic follicles being observed. In contrast, ovary tissues in triangular hysterectomy groups showed no obvious defects on the morphology of ovarian tissue and granulosa cells.

CONCLUSIONS

Our data suggest that subtotal hysterectomy may serve as an alternative to total hysterectomy, with fewer long-term detrimental effects on ovary tissues.

Comparative miRNA expression profile analysis of porcine ovarian follicles: new insights into the initiation mechanism of follicular atresia

Follicular atresia occurs in every stage of ovarian development, which is relevant to female fertility. In the past decade, increasing studies have confirmed that miRNAs, a class of short non-coding RNAs, play an important role in follicular atresia by post-transcription regulation of their target genes. However, the function of miRNAs on follicular atresia initiation is unknown. In the present study, high-throughput small RNA sequencing was performed to analyze differential miRNA expression profiles between healthy (HF) follicles and early atretic (EAF) follicles. A total of 237 conserved miRNA were detected, and the miR-143 is the highest expressed in follicles. Meanwhile, we also found wide sequence variations (isomiRs) in porcine ovarian miRNA, including in 5'un-translation region, core seed sequences and 3'untranslation region. Furthermore, we identified 22 differentially expressed miRNAs in EAF groups compared to HF group, of which 3 miRNAs were upregulated, as well as 19 miRNAs were downregulated, and then the RT-PCR was performed to validate these profiles. The target genes of these differentially expressed miRNAs were predicted by using miRwalk, miRDB, and Targetscan database, respectively. Moreover, the gene ontology and KEGG pathway enrichment established that the regulating functions and signaling pathways of these miRNAs contribute to follicular atresia initiation and cell fate. In conclusion, this study provides new insights into the changes of miRNAs in early atretic follicles to demonstrate their molecular regulation in ovarian follicular atretic initiation.

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.

miR-138-5p promotes chicken granulosa cell apoptosis via targeting SIRT1

Granulosa cell (GC) apoptosis is the main trigger of follicular atresia. MicroRNAs (miRNAs) are 18-22 nt RNAs whose function is primarily determined by their extended seed region and are considered to be involved in the biological functions of follicular development, including follicular atresia, folliculogenesis, and oogenesis. MiR-138-5p is known to act on chicken GCs. In this study, we found that miR-138-5p was enriched in reproductive organs, such as the uterus and ovaries. To examine whether miR-138-5p could regulate the biological process of GCs, miR-138-5p was examined by transfection of cells with a mimic or inhibitor of miR-138-5p. Expression levels of caspase-3 and caspase-9 mRNA and protein were markedly increased or decreased after transfection of the mimic or inhibitor, respectively. Furthermore, following miR-138-5p inhibition, SIRT1, one of the target genes of miR-138-5p, was found to increase the mRNA, which is correlated with the increased levels of BCL2 expression, an anti-apoptotic gene in the chicken GCs. These results suggest that miR-138-5p promotes apoptosis in chicken GCs by targeting SIRT1.

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

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

Mutation of the ETS1 3'UTR interacts with miR-216a-3p to regulate granulosa cell apoptosis in sheep

ETS1, an important member of the ETS transcription factor family, is involved in a variety of physiological processes in living organisms, such as cell development, differentiation, proliferation and apoptosis, and is thought to be associated with embryonic development and reproduction. However, the polymorphism of ETS1 has been rarely studied, and its potential impact on the formation of reproductive traits in sheep remains unclear. Here, we first analyzed polymorphisms of ETS1 in a population of 382 small-tailed Han sheep with a lambing number record using the Kompetitive Allele Specific PCR (KASP) technique. The results showed the presence of a SNP locus rs161611767 (T > C) in the 3'UTR of ETS1. The association analysis showed the lambing number of first, second and third parity in the individuals with the CC genotype (2.51 ± 0.108, 2.51 ± 0.179, 1.27 ± 0.196) was higher than that of individuals with the TT genotype (1.79 ± 0.086, 1.56 ± 0.102, 0.56 ± 0.100) (P < 0.05). Then, molecular biotechnologies were used to investigate the effects of the EST1 rs161611767 mutant locus on host gene expression in sheep and the underlying mechanism of its effect on sheep reproduction. The RT‒qPCR results showed that the expression of ETS1 was higher in individuals with the CC genotype than in those with the TT genotype (P < 0.05). The dual luciferase reporter assay showed that the luciferase activity of ETS1 in sheep with the TT genotype was decreased compared to CC genotype (P < 0.05), confirming the existence of EST1 rs161611767 in the 3'UTR as a functional SNP. Given that the 3'UTR is an important regulatory region of gene transcription and translation, we performed bioinformatics prediction and confirmed that the SNP rs161611767 of ETS1 was a direct functional target of miR-216a-3p using dual luciferase activity assay, and the binding capacity of allele T was stronger than that of allele C. Subsequently, the cell transfection results showed that miR-216a-3p suppressed the endogenous expression of ETS1 in sheep primary granulosa cells (GCs). Finally, CCK-8, EdU, WB detection of marker proteins and flow cytometry were used to detect the effects of miR-216a-3p on GCs viability and proliferation/apoptosis, respectively. The results showed that miR-216a-3p inhibited the proliferation of GCs while promoting apoptosis of GCs. In conclusion, these results demonstrate that the SNP rs161611767 of ETS1 is associated with lambing number in small-tailed Han sheep, and miR-216a-3p can act as a regulatory element binding to the T mutation in rs161611767 to regulate ETS1 expression and affect GCs development, which may indirectly affect the number of lambs in sheep. These studies provide evidence for the involvement of ETS1 polymorphisms in sheep reproduction and are expected to provide new insights to elucidate the molecular genetic mechanisms of lambing traits in sheep.

Quercetin Alleviates Toxicity Induced by High Levels of Copper in Porcine Follicular Granulosa Cells by Scavenging Reactive Oxygen Species and Improving Mitochondrial Function

CuSO4 is the most commonly used feed additive in pig production at present, but long-term ingestion of excessive copper would lead to chronic copper toxicity. High copper could reduce the reproductive efficiency of sows and seriously affect the development of the pig industry. Quercetin (QUE), a powerful antioxidant, reduces toxicity of a number of heavy metals. Porcine granulosa cells (pGCs) are crucial to the fate of follicle development. The present study found that high concentrations of CuSO4 induced ROS production, which resulted in decreased mRNA expression of antioxidant-related genes GPX4, CAT, and SOD2 and increased mRNA expression of SOD1, TRX, and HO-1. The protein expression of antioxidant enzymes SOD2 and HO-1 decreased. Moreover, the concentration of MDA increased, the activity of CAT decreased, and the content of GSH decreased. After high copper treatment, the mitochondrial membrane potential (MMP) was decreased and the morphological structure was changed. However, the combined treatment with Quercetin (QUE) reversed these changes, and the level of cellular oxidative stress decreased. Therefore, we conclude that high copper has oxidative toxicity to pGCs, and QUE could remove the ROS induced by high copper, protect mitochondria from oxidative stress damage, and improve the function of pGCs.

MicroRNA-144-3p protects against chemotherapy-induced apoptosis of ovarian granulosa cells and activation of primordial follicles by targeting MAP3K9

Premature ovarian failure (POF) is defined by amenorrhea, ovarian atrophy, hypoestrogenism, elevated gonadotropin level, and infertility under the age of 40. POF is frequently induced by chemotherapeutic agents. However, the underlying mechanisms regarding chemotherapy-mediated damage to ovarian function are unclear. In this study, enhanced apoptosis of granulosa cells (GCs) and aberrant activation of primordial follicles were observed in a POF mouse model induced by cisplatin. We subsequently observed significant downregulation of miR-144-3p and upregulation of mitogen-activated protein kinase kinase kinase 9 (MAP3K9) in primary ovarian GCs from POF mice, as revealed by microarrays. Furthermore, MAP3K9 expression was higher in human ovarian granulosa cells (COV434) treated with cisplatin and was identified as a novel target of miR-144-3p. Functional analysis revealed that miR-144-3p attenuated cisplatin induced apoptosis of GCs via silencing MAP3K9 expression, which suppressed the activity of the downstream p38 mitogen activated protein kinase (MAPK) pathway. Meanwhile, miR-144-3p prevented premature primordial follicle depletion in cisplatin-induced POF mice through targeting Map3k9, which led to a decline in the phosphorylation and activation of the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/protein kinase b (AKT) pathway. Taken together, this study revealed the protective effects of miR-144-3p on ovarian function and shed light on the epigenetic regulatory mechanism in the development of POF, which might provide new biomarkers for the ovarian reserve.

Effect of induced molting on ovarian function remodeling in laying hens

Induced molting (IM) can restore the laying rate of aged laying hens to the peak level of laying and rejuvenate ovarian function for the second laying cycle. To explore the mechanism of ovarian function remodeling during IM in laying hens, in this study, ninety 71-wk-old laying lady hens with 60% laying rate and uniform weight were selected for molting induction by fasting. Samples (serum and fresh ovarian tissue) were collected on the day before fasting (F0), the 3rd and 16th days of fasting (F3, F16), and the 6th, 15th, 32nd days of refeeding (R6, R15, and R32), and the number of follicles in each period was counted. Then, the reproductive hormone levels in serum and antioxidant levels in ovarian tissues were detected at different stages, and the gene expression of the KIT-PI3K-PTEN-AKT pathway and GDF-9 in ovaries was measured by qRT-PCR. The results showed that the laying rate increased rapidly after refeeding and returned to the prefasting level by R32. At F16 and R6, the number of mature follicles significantly decreased; the number of primary and secondary follicles significantly increased; the contents of follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), and progesterone (P4) in serum decreased; the relative expression of KIT, PI3K, AKT, and GDF-9 significantly increased; and that of PTEN significantly decreased. At R15 and R32, except for GDF-9, which maintained a high expression state, other indicators showed opposing trends to those observed at F16 and R6. In conclusion, IM activated the KIT-PI3K-PTEN-AKT signaling pathway and promoted the activation of primordial follicles during the fasting period and early resumption of feeding; gonadotropin secretion increased gradually, which promoted the rapid development of primary and secondary follicles to mature follicles and ovulation. This study explained the mechanism of ovarian function remodeling in the process of IM and provided a theoretical basis for improving the ovarian function of laying hens and optimizing the IM program.

miR-486 Responds to Apoptosis and Autophagy by Repressing SRSF3 Expression in Ovarian Granulosa Cells of Dairy Goats

The accumulation of ovarian granulosa cell (GC) apoptosis underlies follicular atresia. By comparing the previous sequencing results, miR-486 was found to be differentially expressed at higher levels in the monotocous goat than in the polytocous goat. Unfortunately, the miRNA-mediated mechanisms by which the GC fate is regulated are unknown in Guanzhong dairy goats. Therefore, we investigated miR-486 expression in small and large follicles, as well as its impact on normal GC survival, apoptosis and autophagy in vitro. Here, we identified and characterized miR-486 interaction with Ser/Arg-rich splicing factor 3 (SRSF3) using luciferase reporter analysis, detecting its role in GC survival, apoptosis and autophagy regulation through qRT-PCR, Western blot, CCK-8, EdU, flow cytometry, mitochondrial membrane potential and monodansylcadaverine, etc. Our findings revealed prominent effects of miR-486 in the regulation of GC survival, apoptosis and autophagy by targeting SRSF3, which might explain the high differential expression of miR-486 in the ovaries of monotocous dairy goats. In summary, this study aimed to reveal the underlying molecular mechanism of miR-486 regulation on GC function and its effect on ovarian follicle atresia in dairy goats, as well as the functional interpretation of the downstream target gene SRSF3.

Identification of microRNAs implicated in modulating resveratrol-induced apoptosis in porcine granulosa cells

MicroRNAs (miRNAs) are small, noncoding RNAs that play a crucial role in the complex and dynamic network that regulates the apoptosis of porcine ovarian granulosa cells (POGCs). Resveratrol (RSV) is a nonflavonoid polyphenol compound that is involved in follicular development and ovulation. In previous study, we established a model of RSV treatment of POGCs, confirming the regulatory effect of RSV in POGCs. To investigate the miRNA-level effects of RSV on POGCs to reveal differentially expressed miRNAs, a control group (n = 3, 0 μM RSV group), a low RSV group (n = 3, 50 μM RSV group), and a high RSV group (n = 3, 100 μM RSV group) were created for small RNA-seq. In total, 113 differentially expressed miRNAs (DE-miRNAs) were identified, and a RT-qPCR analysis showed a correlation with the sequencing data. Functional annotation analysis revealed that DE-miRNAs in the LOW vs. CON group may be involved in cell development, proliferation, and apoptosis. In the HIGH vs. CON group, RSV functions were associated with metabolic processes and responses to stimuli, while the pathways were related to PI3K24, Akt, Wnt, and apoptosis. In addition, we constructed miRNA-mRNA networks related to Apoptosis and Metabolism. Then, ssc-miR-34a and ssc-miR-143-5p were selected as key miRNAs. In conclusion, this study provided an improved understanding of effects of RSV on POGCs apoptosis through the miRNA modulations. The results suggest that RSV may promote POGCs apoptosis by stimulating the miRNA expressions and provided a better understanding of the role of miRNAs combined with RSV in ovarian granulosa cell development in pigs.

METTL3-mediated m6A methylation regulates granulosa cells autophagy during follicular atresia in pig ovaries

Follicular atresia is a normal physiological event in mammals, yet its mechanism remains to be studied. Granulosa cell (GC) autophagy is closely associated with follicular atresia. The N6-methyladenosine (m6A) modification is the most common post-transcriptional modification in eukaryotes, but its role in follicular atresia is still unknown. In this study, the possible relationship amongst follicular atresia, GC autophagy and m6A modification was studied. Our results showed that the level of autophagy in GCs increased with the degree of follicle atresia, whereas the overall m6A level decreased. Rapamycin treatment induced atresia in vitro cultured follicles, whereas 3-Methyladenine inhibited follicular atresia. Progressed atretic follicle (PAF) GCs had significantly lower METTL3 levels and significantly higher FTO levels than healthy follicle (HF) GCs. Differential gene expression analysis of GCs in PAF and HF by RNA sequencing was showed that the autophagy-related genes ULK1, ULK2, ATG2A, and ATG2B were significantly elevated in the PAF. In cultured GCs, overexpression of METTL3 significantly decreased the mRNA level of ULK1, as well as the autophagy level, whereas knockdown of METTL3 by RNAi significantly increased the mRNA level of ULK1, as well as the autophagy level. Our results indicate that m6A modification can regulate autophagy in GCs and play a role in the process of porcine follicular atresia.

Androgen-induced exosomal miR-379-5p release determines granulosa cell fate: cellular mechanism involved in polycystic ovaries

Polycystic ovarian syndrome (PCOS) is a complex multi-factorial syndrome associated with androgen excess and anovulatory infertility. In the current study, we investigated the role of dihydrotestosterone-induced exosomal miR-379-5p release in determining the destiny of the developing follicles. Our hypothesis was that androgen regulates granulosa cell miR-379-5p content by facilitating its exosomal release in a follicular-stage dependent manner, a process which determines granulosa cell fate. Compared to human non-PCOS subjects, individuals with PCOS exhibit higher follicular fluid free testosterone levels, lower exosomal miR-379-5p content and granulosa cell proliferation. Androgenized rats exhibited lower granulosa cell miR-379-5p but higher phosphoinositide-dependent kinase-1 (PDK1; a miR-379-5p target) content and proliferation. Androgen reduced granulosa cell miR-379-5p content by increasing its exosomal release in preantral follicles, but not in antral follicles in vitro. Studies with an exosomal release inhibitor confirmed that androgen-induced exosomal miR-379-5p release decreased granulosa cell miR-379-5p content and proliferation. Ovarian overexpression of miR-379-5p suppressed granulosa cell proliferation, and basal and androgen-induced preantral follicle growth in vivo. These findings suggest that increased exosomal miR-379-5p release in granulosa cells is a proliferative response to androgenic stimulation specific for the preantral stage of follicle development and that dysregulation of this response at the antral stage is associated with follicular growth arrest, as observed in human PCOS.

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.

Protective effect of L‑carnitine against oxidative stress injury in human ovarian granulosa cells

Granulosa cells (GCs) are important for supporting and nourishing oocytes during follicular development and maturation. Oxidative stress (OS) injury of GCs can lead to decreased responsiveness of follicles to follicular stimulating hormone (FSH), which will accelerate ovarian senescence and adversely affect oocyte and embryo quality. Since L-carnitine has been previously reported to exert strong antioxidant activity, the present study aimed to explore the possible effects of L-carnitine on OS injury and FSH receptor (FSHR) expression in ovarian GCs, results of which may be of significance for GCs protection. In the present study, OS was induced in vitro in KGN cells by treatment with H₂O₂. KGN cells were cultured and divided into the following four groups: Blank, OS, and 40 and 80 µmol/l L-carnitine pre-treatment groups. In the OS group, cells showed nuclear pyknosis, mitochondria swelled irregularly whilst featuring fractured cristae. In addition, cell viability, ROS levels, superoxide dismutase levels, glutathione levels, malondialdehyde levels, the mitochondrial membrane potential and FSHR expression, as determined by Cell Counting Kit-8 (CCK-8), 2,7-dichloro-dihydrofluorescein diacetate, spectrophotometry, ELISA, spectrophotometry, JC-1 and western blot analyses, respectively, were all significantly different in the OS group compared with those in the control group. However, malonaldehyde levels, reactive oxygen species levels and the apoptosis rate according to flow cytometry were all significantly increased compared with those in the control. Compared with those in the OS group, the morphology of cells and mitochondria in the L-carnitine pre-treatment groups were improved, whilst cell viability and the expression of FSHR were significantly increased but oxidative stress injury was decreased. The present results suggest that L-carnitine can protect the cells from OS damage induced by H₂O₂, enhance antioxidant activity whilst suppressing the apoptosis of GCs, in addition to preserving FSHR expression in GCs under OS. Therefore, the present study revealed that the introduction of L-carnitine in clinical medicine or dietary supplement may protect GCs, improve follicular quality and female reproductive function.

SDNOR, a Novel Antioxidative lncRNA, Is Essential for Maintaining the Normal State and Function of Porcine Follicular Granulosa Cells

Increasing evidence shows that lncRNAs, an important kind of endogenous regulator, are involved in the regulation of follicular development and female fertility, but the mechanism remain largely unknown. In this study, we found that SDNOR, a recently identified antiapoptotic lncRNA, is a potential multifunctional regulator in porcine follicular granulosa cells (GCs) through RNA-seq and multi-dimension analyses. SDNOR-mediated regulatory networks were established and identified that SOX9, a transcription factor inhibited by SDNOR, mediates SDNOR's regulation of the transcription of downstream targets. Functional analyses showed that loss of SDNOR significantly impairs GC morphology, inhibits cell proliferation and viability, reduces E2/P4 index, and suppresses the expression of crucial markers, including PCNA, Ki67, CDK2, CYP11A1, CYP19A1, and StAR. Additionally, after the detection of ROS, SOD, GSH-Px, and MDA, we found that SDNOR elevates the resistance of GCs to oxidative stress (OS) and also inhibits OS-induced apoptosis. Notably, GCs with high SDNOR levels are insensitive to oxidative stress, leading to lower apoptosis rates and higher environmental adaptability. In summary, our findings reveal the regulation of porcine GCs in response to oxidative stress from the perspective of lncRNA and demonstrate that SDNOR is an essential antioxidative lncRNA for maintaining the normal state and function of GCs.

Low-density small extracellular vesicles in bovine follicular fluid carrying let-7i target FASLG to inhibit granulosa cells apoptosis

Apoptosis of granulosa cells is a key factor in mammalian follicular atresia. It has a significant impact on oocyte development and maturation. Extracellular vesicles (EVs) are a group of highly heterogeneous population. Previous studies have found that ovarian follicular fluid is rich in EVs. In the present study, the follicular fluid of 3-5 mm follicles from bovine ovaries without corpus luteum was collected, and a subtype of small EVs (sEVs), low-density small EVs (LD-sEVs), was successfully isolated by differential ultracentrifugation combined with iodixanol density gradient centrifugation. LD-sEVs were identified using transmission electron microscope, nanoparticle tracking analysis and Western blot. Flow cytometry, Quantitative reverse transcription PCR (RT-qPCR), Western blot, and other methods were used to detect the effect of LD-sEVs on follicular granulosa cell apoptosis. After that, let-7i, a highly expressed miRNA component in LD-sEVs, was screened and target validation was carried out in granulosa cells. The results showed that LD-sEVs could be taken up by granulosa cells and inhibited the apoptosis. Further research found that let-7i inhibits the apoptosis of granulosa cells by targeting FASLG. It plays an important role in regulating the apoptosis of follicular granulosa cells, which may affect follicular development.

Exposure to Di-(2-Ethylhexyl) phthalate drives ovarian dysfunction by inducing granulosa cell pyroptosis via the SLC39A5/NF-κB/NLRP3 axis

Endocrine-disrupting chemicals (EDCs) have been reported to affect populations by disrupting the human endocrine system. Di-(2-ethylhexyl) phthalate (DEHP) is an EDC that is present in various consumer products. Exposure to DEHP could contribute to reproductive system dysfunction, with subsequent adverse female reproductive outcomes. Granulosa cells (GCs) play essential roles in ovarian function and fertility. To further reveal the underlying mechanism by which DEHP impairs female fertility and affects the normal function of GCs, in vivo and in vitro experiments were performed. Transcript sequencing was used to identify genes that were differentially expressed in GCs after DEHP treatment. SLC39A5 was shown to be overexpressed in the DEHP group compared to the normal control group. DEHP treatment and overexpression of SLC39A5 activated NF-κB-related factors, followed by an increase in the transcript expression level of NLRP3. NLRP3 inflammasomes play crucial roles in pyroptosis by acting as sensors. Pyroptosis is a type of inflammation-related cell death associated with various diseases, including ovarian cancer and polycystic ovary syndrome. Activation of NF-κB contributed to the upregulation of pyroptosis in GCs, while pyroptosis factors were downregulated after the inhibition of NF-κB with JSH-23. The same phenomenon was also observed in a mouse model in which DEHP-treated mice had higher expression levels of NF-κB and pyroptosis markers in GCs. Moreover, this phenomenon could be partially reversed by the NF-κB inhibitor JSH-23. DEHP treatment also disrupted the normal expression of ovarian function-related genes and inhibited the proliferation of GCs. Reproductive system impairment was observed in mice exposed to DEHP. DEHP-treated mice had a lower body weight, smaller reproductive organs, fewer healthy follicles, and diminished ovarian reserve. Thus, DEHP contributes to ovarian dysfunction by inducing pyroptosis via the SLC39A5/NF-κB/NLRP3 axis in GCs.

Granulosa cells undergo BPA-induced apoptosis in a miR-21-independent manner

Bisphenol A (BPA) is a harmful endocrine disrupting compound that alters not only classical cellular mechanisms but also epigenetic mechanisms. Evidence suggests that BPA-induced changes in microRNA expression can explain, in part, the changes observed at both the molecular and cellular levels. BPA is toxic to granulosa cells (GCs) as it can activate apoptosis, which is known to contribute to increased follicular atresia. miR-21 is a crucial antiapoptotic regulator in GCs, yet the exact function in a BPA toxicity model remains unclear. BPA was found to induce bovine GC apoptosis through the activation of several intrinsic factors. BPA reduced live cells counts, increased late apoptosis/necrosis, increased apoptotic transcripts (BAX, BAD, BCL-2, CASP-9, HSP70), increased the BAX/Bcl-2 ratio and HSP70 at the protein level, and induced caspase-9 activity at 12 h post-exposure. miR-21 inhibition increased early apoptosis and, while it did not influence transcript levels or caspase-9 activity, it did elevate the BAX/Bcl-2 protein ratio and HSP70 in the same manner as BPA. Overall, this study shows that miR-21 plays a molecular role in regulating intrinsic mitochondrial apoptosis; however, miR-21 inhibition did not make the cells more sensitive to BPA. Therefore, apoptosis induced by BPA in bovine GCs is miR-21 independent.

Recombinant human chorionic gonadotropin and gonadotropin-releasing hormone agonist differently affect the profile of extracellular vesicle microRNAs in human follicular fluid

PURPOSE

To compare the expression profile of extracellular vesicle microRNAs (EV-miRNAs) derived from follicular fluid after a trigger with recombinant human chorionic gonadotropin (r-hCG) or with a gonadotropin-releasing hormone GnRH agonist (GnRH-a) for final oocyte maturation.

METHODS

A retrospective analysis of a prospective cohort. Women undergoing in vitro fertilization at a tertiary university-affiliated hospital were recruited between 2014 and 2016. EV-miRNAs were extracted from the follicular fluid of a single follicle, and their expression was assessed using TaqMan Open Array®. Genes regulated by EV-miRNAs were analyzed using miRWalk2.0 Targetscan database, DAVID Bioinformatics Resources, Kyoto-Encyclopedia of Genes and Genomes (KEGG), and Gene Ontology (GO).

RESULTS

Eighty-two women were included in the r-hCG trigger group and 9 in the GnRH-a group. Of 754 EV-miRNAs screened, 135 were detected in at least 50% of the samples and expressed in both groups and were further analyzed. After adjusting for multiple testing, 41 EV-miRNAs whose expression levels significantly differed between the two trigger groups were identified. Bioinformatics analysis of the genes regulated by these EV-miRNAs showed distinct pathways between the two triggers, including TGF-beta signaling, cell cycle, and Wnt signaling pathways. Most of these pathways regulate cascades associated with apoptosis, embryo development, implantation, decidualization, and placental development.

CONCLUSIONS

Trigger with GnRH-a or r-hCG leads to distinct EV-miRNAs expression profiles and to downstream biological effects in ovarian follicles. These findings may provide an insight for the increased apoptosis and the lower implantation rates following GnRH-a trigger vs. r-hCG in cases lacking intensive luteal phase support.

Sirtuin 3 regulation: a target to alleviate β-hydroxybutyric acid-induced mitochondrial dysfunction in bovine granulosa cells

BACKGROUND

During the transition period, the insufficient dry matter intake and a sharply increased in energy consumption to produce large quantities of milk, high yielding cows would enter a negative energy balance (NEB) that causes an increase in ketone bodies (KBs) and decrease in reproduction efficiency. The excess concentrations of circulating KBs, represented by β-hydroxybutyric acid (BHBA), could lead to oxidative damage, which potentially cause injury to follicular granulosa cells (fGCs) and delayed follicular development. Sirtuin 3 (Sirt3) regulates mitochondria reactive oxygen species (mitoROS) homeostasis in a beneficial manner; however, the molecular mechanisms underlying its involvement in the BHBA-induced injury of fGCs is poorly understood. The aim of this study was to explore the protection effects and underlying mechanisms of Sirt3 against BHBA overload-induced damage of fGCs.

RESULTS

Our findings demonstrated that 2.4 mmol/L of BHBA stress increased the levels of mitoROS in bovine fGCs. Further investigations identified the subsequent mitochondrial dysfunction, including an increased abnormal rate of mitochondrial architecture, mitochondrial permeability transition pore (MPTP) opening, reductions in mitochondrial membrane potential (MMP) and Ca²⁺ release; these dysfunctions then triggered the caspase cascade reaction of apoptosis in fGCs. Notably, the overexpression of Sirt3 prior to treatment enhanced mitochondrial autophagy by increasing the expression levels of Beclin-1, thus preventing BHBA-induced mitochondrial oxidative stress and mitochondrial dysfunction in fGCs. Furthermore, our data suggested that the AMPK-mTOR-Beclin-1 pathway may be involved in the protective mechanism of Sirt3 against cellular injury triggered by BHBA stimulation.

CONCLUSIONS

These findings indicate that Sirt3 protects fGCs from BHBA-triggered injury by enhancing autophagy, attenuating oxidative stress and mitochondrial damage. This study provides new strategies to mitigate the fGCs injury caused by excessive BHBA stress in dairy cows with ketosis.

Small Peptides from Periplaneta americana Inhibits Oxidative Stress-Induced KGN Cell Apoptosis by Regulating Mitochondrial Function Through Bcl2L13

This study examined the protective effects of small peptides from Periplaneta americana against H₂O₂-induced mitochondrial injury in human ovarian granulosa cells. The ATP level and mitochondrial membrane potential as well as the quantity and ultrastructure of mitochondria in cells were detected. Mitochondrial DNA copy number and expression levels of Bcl2L13, LC3B, and p62 were tested. Targeted silencing of Bcl2L13 expression in KGN cells. The expression levels of Bcl2L13 and LC3B as well as interaction were evaluated. The ATP level, mtDNA-CN, and MMP of the H₂O₂ group were significantly lower than those of the normal control group (P < 0.05), accompanied by a reduction in mitochondrial mass and mitochondrial fluorescence intensity (P < 0.05). However, the ATP level, mtDNA, and MMP in KGN cells were increased after SPPA treatment (P < 0.05). Scanning electron microscopy shows that SPPA ameliorates H₂O₂-induced structural damage to mitochondria. Moreover, the expression levels of Bcl2L13 and p62 in the H₂O₂ group were downregulated significantly compared with those of the normal control group (P < 0.05), while LC3B was upregulated (P < 0.05). After SPPA treatment, the expression levels of Bcl2L13 and p62 were upregulated (P < 0.05), while LC3B was downregulated (P < 0.05). The Co-IP results indicated that Bcl2L13 and LC3B interacted, and this interaction was weakened after cell treatment with H₂O₂, and dissociation between Bcl2L13 and LC3B declined after SPPA treatment. SPPA inhibits KGN cell apoptosis induced by oxidative stress via inhibition of mitochondrial injury Bcl2L13-mediated mitochondrial autophagy might participate in the regulation process.

Epigenetic regulation in premature ovarian failure: A literature review

Premature ovarian failure (POF), or premature ovarian insufficiency (POI), is a multifactorial and heterogeneous disease characterized by amenorrhea, decreased estrogen levels and increased female gonadotropin levels. The incidence of POF is increasing annually, and POF has become one of the main causes of infertility in women of childbearing age. The etiology and pathogenesis of POF are complex and have not yet been clearly elucidated. In addition to genetic factors, an increasing number of studies have revealed that epigenetic changes play an important role in the occurrence and development of POF. However, we found that very few papers have summarized epigenetic variations in POF, and a systematic analysis of this topic is therefore necessary. In this article, by reviewing and analyzing the most relevant literature in this research field, we expound on the relationship between DNA methylation, histone modification and non-coding RNA expression and the development of POF. We also analyzed how environmental factors affect POF through epigenetic modulation. Additionally, we discuss potential epigenetic biomarkers and epigenetic treatment targets for POF. We anticipate that our paper may provide new therapeutic clues for improving ovarian function and maintaining fertility in POF patients.

Chitosan oligosaccharide improves ovarian granulosa cells inflammation and oxidative stress in patients with polycystic ovary syndrome

Introduction

Polycystic Ovary Syndrome (PCOS) is the most common reproductive endocrine disorder among women of reproductive age, which is one of the main causes of anovulatory infertility. Even though the rapidly developed assisted reproductive technology (ART) could effectively solve fertility problems, some PCOS patients still have not obtained satisfactory clinical outcomes. The poor quality of oocytes caused by the abnormal follicular development of PCOS may directly contribute to the failure of ART treatment. Ovarian granulosa cells (GCs) are the most closely related cells to oocytes, and changes in their functional status have a direct impact on oocyte formation. Previous studies have shown that changes in the ovarian microenvironment, like oxidative stress and inflammation, may cause PCOS-related aberrant follicular development by impairing the physiological state of the GCs. Therefore, optimizing the ovarian microenvironment is a feasible method for enhancing the development potential of PCOS oocytes.

Methods

In this study, we first detected the expression of inflammatory-related factors (TGF-β1, IL-10, TNFα, IL-6) and oxidative stress-related factors (HIF-1α and VEGFA), as well as the proliferation ability and apoptosis level of GCs, which were collected from control patients (non-PCOS) and PCOS patients, respectively. Subsequently, human ovarian granulosa cell line (KGN) cells were used to verify the anti-inflammatory and anti-oxidative stress effects of chitosan oligosaccharide (COS) on GCs, as well as to investigate the optimal culture time and concentration of COS. The optimal culture conditions were then used to culture GCs from PCOS patients and control patients.

Results

The results showed that GCs from PCOS patients exhibited obvious inflammation and oxidative stress and significantly reduced proliferation and increased apoptosis. Furthermore, COS can increase the expression of anti-inflammatory factors (TGF-β1 and IL-10) and decrease the expression of pro-inflammatory factors (TNFα and IL-6), as well as promote the proliferation of GCs. Moreover, we found that COS can reduce the level of reactive oxygen species in GCs under oxidative stress by inhibiting the expression of HIF-1α and VEGFA and by suppressing the apoptosis of GCs induced by oxidative stress.

Conclusion

We find that inflammation and oxidative stress exist in the GCs of PCOS patients, and COS can reduce these factors, thereby improving the function of GCs.

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.

A review of autoimmunity and immune profiles in patients with primary ovarian insufficiency

Primary ovarian insufficiency (POI) is a complicated clinical syndrome characterized by progressive deterioration of ovarian function. Autoimmunity is one of the main pathogenic factors affecting approximately 10% to 55% of POI cases. This review mainly focuses on the role of autoimmunity in the pathophysiology of POI and the potential therapies for autoimmunity-related POI. This review concluded that various markers of ovarian reserve, principally anti-Müllerian hormone, could be negatively affected by autoimmune diseases. The presence of lymphocytic oophoritis, anti-ovarian autoantibodies, and concurrent autoimmune diseases, are the main characteristics of autoimmune POI. T lymphocytes play the most important role in the immune pathogenesis of POI, followed by disorders of other immune cells and the imbalance between pro-inflammatory and anti-inflammatory cytokines. A comprehensive understanding of immune characteristics of patients with autoimmune POI and the underlying mechanisms is essential for novel approaches of treatment and intervention for autoimmune POI.

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.

The Role of Circular RNAs in the Physiology and Pathology of the Mammalian Ovary

Circular RNAs (circRNAs) are an abundant class of endogenous non-coding RNAs (ncRNAs) generated from exonic, intronic, or untranslated regions of protein-coding genes or intergenic regions. The diverse, stable, and specific expression patterns of circRNAs and their possible functions through cis/trans regulation and protein-coding mechanisms make circRNA a research hotspot in various biological and pathological processes. It also shows practical value as biomarkers, diagnostic indicators, and therapeutic targets. This review summarized the characteristics, classification, biogenesis and elimination, detection and confirmation, and functions of circRNAs. We focused on research advances circRNAs in the mammalian ovary under conditions including ovarian cancer, polycystic ovarian syndrome (PCOS), and maternal aging, as well as during reproductive status, including ovarian follicle development and atresia. The roles of circRNAs in high reproductive traits in domestic animals were also summarized. Finally, we outlined some obstructive factors and prospects to work with circRNA, aiming to provide insights into the functional research interests of circRNAs in the reproduction and gynecology areas.

Long non‑coding RNA NEAT1 promotes mouse granulosa cell proliferation and estradiol synthesis by sponging miR‑874‑3p

It has been reported that long non-coding RNA nuclear-enriched abundant transcript 1 (NEAT1) is involved in follicular growth and multiple ovarian diseases, but not the physiological function of NEAT1 in mouse granulosa cells (mGCs). Therefore, the aim of the present study was to investigate the biological roles and regulatory mechanisms of NEAT1 in mGCs. The biological effects of NEAT1 on mGCs proliferation, apoptosis, production of 17β-Estradiol (E2) and progesterone (P4) were investigated using MTS, flow cytometry and enzyme-linked immunosorbent assays, respectively. The association between NEAT1 and microRNA (miR)-874-3p was verified using luciferase reporter assay and RNA immunoprecipitation analysis. The results demonstrated that the knockdown of NEAT1 in mGC cells significantly promoted mGCs cell proliferation, inhibited apoptosis and increased the production of E2 and P4 in mGCs. The interference-mediated effect of NEAT1 on mGCs could be partially reversed by the downregulation of miR-874-3p. Overall, these results indicated that NEAT1 served as a competing endogenous RNA by competitively binding with miR-874-3p, thereby modulating mGCs proliferation and the production of E2 and P4 in mGCs.

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.

Profiling and Functional Analysis of long non-coding RNAs in yak healthy and atretic follicles

Yak is the livestock on which people live in plateau areas, but its fecundity is low. Follicular development plays a decisive role in yak reproductive performance. As an important regulatory factor, the expression of long non-coding RNA (lncRNAs) in yak follicular development and its regulatory mechanism remains unclear. To explore the differentially expressed lncRNAs between healthy and atretic follicular in yaks. We used RNA-seq to construct lncRNA, miRNA, and mRNA expression profiles in yak atretic and healthy follicles, and the RNA sequence results were identified by qPCR. In addition, the correlation of lncRNA and targeted mRNA was also analyzed by Starbase software. Moreover, lncRNA/miRNA/mRNA networks were constructed by Cytoscape software, and the network was verified by dual-luciferase analysis. A total of 682 novel lncRNAs, 259 bta-miRNAs, and 1704 mRNAs were identified as differentially expressed between healthy and atretic follicles. Among them, 135 mRNAs were positively correlated with lncRNA expression and 97 were negatively correlated, which may be involved in the yak follicular development. In addition, pathway enrichment analysis of differentially expressed lncRNA host genes by Kyoto Genome Encyclopedia (KEGG) showed that host genes were mainly involved in hormone secretion, granulosa cell apoptosis, and follicular development. In conclusion, we identified a series of novel lncRNAs, constructed the lncRNA ceRNA regulatory network, and provided comprehensive resources for exploring the role of lncRNAs in yak ovarian follicular development.

miR-10a-5p inhibits chicken granulosa cells proliferation and Progesterone(P4) synthesis by targeting MAPRE1 to suppress CDK2

The proliferation and steroid hormone synthesis of granulosa cells (GCs) are essential for ovarian follicle growth and ovulation, which are necessary to support the normal function of the follicle. Numerous studies suggest that miRNAs play key roles in this process. In this study, we report a novel role for miR-10a-5p that inhibits ovarian GCs proliferation and progesterone (P4) synthesis in chicken. Specifically, we found that miR-10a-5p significantly decreased the P4 secretion by quantitative real-time PCR (qRT-PCR), enzyme-linked immunosorbent assay (ELISA), and western blot. Moreover, we observed that miR-10a-5p can inhibit the proliferation of chicken GCs through the investigation of cell proliferation gene expression, cell counting kit 8 (CCK-8), cell cycle progression, and 5-ethynyl-2'-deoxyuridine (EdU) assay. Then we screened a target gene MAPRE1 of miR-10a-5p, which can promote P4 synthesis and proliferation of GCs. To explore how miR-10a-5p affects cell cycle by MAPRE1, we investigated the interaction between MAPRE1 and cyclin-dependent kinase 2 (CDK2) by Co-Immunoprecipitation (Co-IP), and then we found that MAPRE1 can form a complex with CDK2. In addition, miR-10a-5p was found to inhibit CDK2 expression by repressing the expression of MAPRE1. Overall, our results indicate that miR-10a-5p regulates the proliferation and P4 synthesis of chicken GCs by targeting MAPRE1 to suppress CDK2.

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.