BRE modulates granulosa cell death to affect ovarian follicle development and atresia in the mouse

Roundup® induces premature senescence of mouse granulosa cells via mitochondrial ROS-triggered NLRP3 inflammasome activation

Roundup, a glyphosate-based herbicide widely used in agriculture, has raised concerns regarding its potential impact on human health due to the detection of its residues in human urine and serum. Granulosa cells are essential for oocyte growth and follicle development. Previous research has shown that Roundup could affect steroid synthesis, increases oxidative stress, and induces apoptosis in granulosa cells. However, little is known about the effects of Roundup on NLRP3 (nucleotide binding oligomerization domain-like receptor family pyrin-containing domain protein 3) inflammasome activation and cellular senescence in granulosa cells. Here, we provided evidence that exposure to Roundup induced premature senescence in mouse granulosa cells through the activation of NLRP3 inflammasome triggered by mitochondrial ROS. Our findings demonstrated that Roundup significantly reduced the viability of granulosa cells under in vitro culture conditions. It also disrupted mitochondrial function and induced oxidative stress in these cells. Subsequent investigations showed that NLRP3 inflammasome was activated in treated granulosa cells, as evidenced by the upregulation of inflammasome-related genes and the processing of inflammatory cytokines IL-1β and IL-1α into their mature forms. Consequently, premature cellular senescence occurred in response to the challenge posed by Roundup. Notably, direct inhibition of NLRP3 inflammasome with MCC950 does not alleviate mitochondrial damage and oxidative stress. However, supplementation of resveratrol, which has been known to attenuate mitochondrial damage and oxidative stress, effectively mitigated the inflammatory response and the expression of senescence-related markers, and prevented the senescence in granulosa cells. These results suggested that mitochondrial function and oxidative homeostasis might play pivotal roles as upstream regulators of NLRP3 inflammasome. In summary, our findings indicated that the premature senescence of granulosa cells caused by mitochondrial ROS-triggered NLRP3 inflammasome activation might contribute to the ovarian toxicity of Roundup, in addition to its known effects on steroidogenesis and apoptosis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43188-024-00229-0.

Zinc deficiency deteriorates ovarian follicle development and function by inhibiting mitochondrial function

Zinc (Zn) is a crucial trace element essential for human growth and development, particularly for reproductive health. Previous research has shown a decrease in serum zinc concentration with age and individuals with conditions such as polycystic ovary syndrome (PCOS) and diabetes mellitus. However, the specific effects of zinc deficiency on the female reproductive system, especially ovarian function, are not fully understood. In our study, we observed a significant reduction in the total number of follicles and mature follicles in the zinc deficiency group. This reduction correlated with decreased level of anti-Mullerian hormone (AMH) and abnormal gene expression affecting hormone secretion regulation. Furthermore, we found that zinc deficiency disrupted mitochondrial dynamics, leading to oxidative stress in the ovaries, which further inhibited autophagy and increased ovarian apoptosis. These changes ultimately resulted in the failure of germinal vesicle breakdown (GVBD) and reduced oocyte quality. Meanwhile, administration of zinc glycine effectively alleviated the oocyte meiotic arrest caused by dietary zinc deficiency. In conclusion, our findings demonstrated that dietary zinc deficiency can affect hormone secretion and follicle maturation by impairing mitochondrial function and autophagy.

Indole-3-carbinol ameliorates ovarian damage in female old mice through Nrf2/HO-1 pathway activation

Ovarian aging leads to infertility and birth defects. We aimed to clarify the role of Indole-3-carbinol (I3C) in resistance to oxidative stress, apoptosis, and fibrosis in ovarian aging. I3C was administered via intraperitoneal injection for 3 weeks in young or old mice. Immunohistochemistry; Masson, Sirius red, and TUNEL staining; follicle counting; estrous cycle analysis; and Western blotting were used for validating the protective effect of I3C against ovarian senescence. Human granulosa-like tumor cell line and primary granulosa cells were used for in vitro assay. The results indicated that I3C inhibited ovarian fibrosis and apoptosis while increasing the number of primordial follicles. Mechanistic studies have shown that I3C promoted the nuclear translocation of nuclear factor-erythroid 2-related factor (Nrf2) and upregulated the expression of heme oxygenase 1 (HO-1). Additionally, I3C increased cell viability and decreased lactate dehydrogenase, malondialdehyde, reactive oxygen species and JC-1 levels. Furthermore, the antioxidant effect of I3C was found to be dependent on the activation of Nrf2 and HO-1, as demonstrated by the disappearance of the effect upon inhibition of Nrf2 expression. In conclusion, I3C can alleviate the ovarian damage caused by aging and may be a protective agent to delay ovarian aging.

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.

Disruption of Zar1 leads to arrested oogenesis by regulating polyadenylation via Cpeb1 in tilapia (Oreochromis niloticus)

Oogenesis is a complex process regulated by precise coordination of multiple factors, including maternal genes. Zygote arrest 1 (zar1) has been identified as an ovary-specific maternal gene that is vital for oocyte-to-embryo transition and oogenesis in mouse and zebrafish. However, its function in other species remains to be elucidated. In the present study, zar1 was identified with conserved C-terminal zinc finger domains in Nile tilapia. zar1 was highly expressed in the ovary and specifically expressed in phase I and II oocytes. Disruption of zar1 led to the failed transition from oogonia to phase I oocytes, with somatic cell apoptosis. Down-regulation and failed polyadenylation of figla, gdf9, bmp15 and wee2 mRNAs were observed in the ovaries of zar1-/- fish. Cpeb1, a gene essential for polyadenylation that interacts with Zar1, was down-regulated in zar1-/- fish. Moreover, decreased levels of serum estrogen and increased levels of androgen were observed in zar1-/- fish. Taken together, zar1 seems to be essential for tilapia oogenesis by regulating polyadenylation and estrogen synthesis. Our study shows that Zar1 has different molecular functions during gonadal development by the similar signaling pathway in different species.

Resveratrol-βcd inhibited premature ovarian insufficiency progression by regulating granulosa cell autophagy

BACKGROUND

The ovarian environment of premature ovarian insufficiency (POI) patients exhibits immune dysregulation, which leads to excessive secretion of numerous proinflammatory cytokines that affect ovarian function. An abnormal level of macrophage polarization directly or indirectly inhibits the differentiation of ovarian granulosa cells and steroid hormone production, ultimately leading to POI. Resveratrol, as a health supplement, has been widely recognized for its safety. There is a substantial amount of evidence indicating that resveratrol and its analogs possess significant immune-regulatory functions. It has also been reported that resveratrol can effectively inhibit the progression of POI. However, the underlying immunological and molecular mechanisms through which resveratrol inhibits the progression of POI are still unclear.

RESULTS

Our preliminary reports have shown that resveratrol-βcd, the beta-cyclodextrin complex of resveratrol, significantly enhances the stability of resveratrol. Resveratrol-βcd could regulate the dysfunctional immune status of macrophages and T cells in the tumor microenvironment. In this study, we treated busulfan and cyclophosphamide (B/C)-treated mice, which were used as a POI model, with resveratrol-βcd. After resveratrol-βcd treatment, the levels of IL-6 in the ovaries were significantly increased, and the progression of POI was suppressed. IL-6 activated granulosa cells (GCs) through soluble IL-6R (sIL-6R), promoting autophagy in GCs. Resveratrol-βcd and IL-6 had a synergistic effect on enhancing autophagy in GCs and promoting E2 secretion.

CONCLUSIONS

We partially elucidated the immune mechanism by which resveratrol inhibits the progression of POI and the autophagy-regulating function of GCs. This provides a theoretical basis for using resveratrol to prevent POI in future studies and clinical guidance.

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.

HDAC1-Mediated lncRNA Stimulatory Factor of Follicular Development to Inhibit the Apoptosis of Granulosa Cells and Regulate Sexual Maturity through miR-202-3p-COX1 Axis

Abnormal sexual maturity exhibits significant detrimental effects on adult health outcomes, and previous studies have indicated that targeting histone acetylation might serve as a potential therapeutic approach to regulate sexual maturity. However, the mechanisms that account for it remain to be further elucidated. Using the mouse model, we showed that Trichostatin A (TSA), a histone deacetylase (HDAC) inhibitor, downregulated the protein level of Hdac1 in ovaries to promote the apoptosis of granulosa cells (GCs), and thus arrested follicular development and delayed sexual maturity. Using porcine GCs as a cell model, a novel sexual maturity-associated lncRNA, which was named as the stimulatory factor of follicular development (SFFD), transcribed from mitochondrion and mediated by HDAC1, was identified using RNA sequencing. Mechanistically, HDAC1 knockdown significantly reduced the H3K27ac level at the -953/-661 region of SFFD to epigenetically inhibit its transcription. SFFD knockdown released miR-202-3p to reduce the expression of cyclooxygenase 1 (COX1), an essential rate-limited enzyme involved in prostaglandin synthesis. This reduction inhibited the proliferation and secretion of 17β-estradiol (E2) while promoting the apoptosis of GCs. Consequently, follicular development was arrested and sexual maturity was delayed. Taken together, HDAC1 knockdown-mediated SFFD downregulation promoted the apoptosis of GCs through the miR-202-3p-COX1 axis and lead to delayed sexual maturity. Our findings reveal a novel regulatory network modulated by HDAC1, and HDAC1-mediated SFFD may be a promising new therapeutic target to treat delayed sexual maturity.

A rat study on the PTEN expression in ovarian tissue in PCOS and folliculogenesis

The objective of this investigation was to examine alterations in PTEN expression within ovarian tissue in a rat model of polycystic ovary syndrome (PCOS). The analysis also encompassed the examination of PTEN alterations in the ovarian tissue throughout the process of folliculogenesis in rats with normal ovulatory cycles. The study involved 12 adult female Sprague‒Dawley rats randomly assigned to the letrozole-induced polycystic ovary syndrome (PCOS) group as part of an animal-based research endeavour. The sections derived from the ovaries were subjected to immunohistochemical staining for PTEN. The evaluation of PTEN staining levels in ovarian tissues was conducted using electron microscopy. Follicle counts, as well as hormonal and biochemical analyses (serum luteinising hormone (LH), follicle-stimulating hormone (FSH), anti-Müllerian hormone (AMH), testosterone, oestradiol levels and serum glucose, triglyceride, HDL and LDL-cholesterol levels), were conducted to provide evidence of the manifestation of polycystic ovary syndrome (PCOS) in rats. The number of primordial and Graafian follicles in the PCOS group decreased significantly, and the number of primary, secondary and antral follicles increased significantly. PTEN expression was found to be significantly higher in the PCOS group than in the control group in the primordial follicle oocyte cytoplasm, primordial follicle granulosa cells, primary follicle oocyte cytoplasm, primary follicle granulosa cells, antral follicle oocyte cytoplasm, antral follicle granulosa cells, and corpus luteum (p = 0.007, p = 0.001, p = 0.001, p = 0.001, p = 0.001, p = 0.002, and p = 0.018, respectively). In the non-PCOS group, a time-dependent comparison of the amount of oocyte cytoplasm and PTEN staining in granulosa cells of the oocytes at different stages of development was performed. While the follicles were developing from the primordial follicle to the primary and antral follicle, the amount of PTEN staining in the oocyte cytoplasm decreased, whereas the PTEN activity in the granulosa cells increased as the oocyte developed (p = 0.001 and p = 0.001, respectively). The current investigation demonstrated changes in PTEN expression in ovarian tissue throughout the course of normal folliculogenesis, as well as in instances of disrupted folliculogenesis, with a focus on rats with PCOS.

miR-143-3p Promotes Ovarian Granulosa Cell Senescence and Inhibits Estradiol Synthesis by Targeting UBE2E3 and LHCGR

The ovary is a highly susceptible organ to senescence, and granulosa cells (GCs) have a crucial role in oocyte development promotion and overall ovarian function maintenance. As age advances, GCs apoptosis and dysfunction escalate, leading to ovarian aging. However, the molecular mechanisms underpinning ovarian aging remain poorly understood. In this study, we observed a correlation between the age-related decline of fertility and elevated expression levels of miR-143-3p in female mice. Moreover, miR-143-3p was highly expressed in senescent ovarian GCs. The overexpression of miR-143-3p in GCs not only hindered their proliferation and induced senescence-associated secretory phenotype (SASP) but also impeded steroid hormone synthesis by targeting ubiquitin-conjugating enzyme E2 E3 (Ube2e3) and luteinizing hormone and human chorionic gonadotropin receptor (Lhcgr). These findings suggest that miR-143-3p plays a substantial role in senescence and steroid hormone synthesis in GCs, indicating its potential as a therapeutic target for interventions in the ovarian aging process.

A novel trans-acting lncRNA of ACTG1 that induces the remodeling of ovarian follicles

Previous studies have implicated the attractive role of long noncoding RNAs (lncRNAs) in the remodeling of mammalian tissues. The migration of granulosa cells (GCs), which are the main supporting cells in ovarian follicles, stimulates the follicular remodeling. Here, with the cultured GCs as the follicular model, the actin gamma 1 (ACTG1) was observed to significantly promote the migration and proliferation while inhibit the apoptosis of GCs, suggesting that ACTG1 was required for ovarian remodeling. Moreover, we identified the trans-regulatory lncRNA of ACTG1 (TRLA), which was epigenetically targeted by histone H3 lysine 4 acetylation (H3K4ac). Mechanistically, the 2-375 nt of TRLA bound to ACTG1's mRNA to increase the expression of ACTG1. Furthermore, TRLA facilitated the migration and proliferation while inhibited the apoptosis of GCs, thereby accelerating follicular remodeling. Besides, TRLA acted as a ceRNA for miR-26a to increase the expression of high-mobility group AT-hook 1 (HMGA1). Collectively, TRLA induces the remodeling of ovarian follicles via complementary to ACTG1's mRNA and regulating miR-26a/HMGA1 axis in GCs. These observations revealed a novel and promising trans-acting lncRNA mechanism mediated by H3K4ac, and TRLA might be a new target to restore follicular remodeling and development.

Bisphenol A interferes with lncRNA Fhadlos2 and RUNX3 association in adolescent mouse ovary

Bisphenol A (BPA) has a number of adverse effects on the reproductive development of females. In particular, the mechanism of disruption of ovarian development in adolescent mice is still unclear. Based on transcriptome sequencing results, a differentially expressed lncRNA, Fhad1os2, was detected in the ovaries of BPA-exposed pubertal mice. In our study, the lncRNA Fhad1os2, localized in the ovarian granulosa cell cytoplasm, could regulate the proliferation of mouse ovarian granulosa cells. Mechanistically, the results of RNA pull-down experiments as well as mass spectrometry analysis showed that ERα, an interfering signaling molecule of BPA, could directly bind lncRNA Fhad1os2 and decrease the transcription of lncRNA Fhad1os2 in response to the estrogen-like effect of BPA. BPA exposure also caused abnormal lncRNA Fhad1os2 pulldown protein-related signaling pathways in the ovaries of adolescent mice. Furthermore, lncRNA Fhad1os2 interacted with RUNX3, a transcription factor related to follicle development and hormone synthesis. As a negative regulator, lncRNA Fhad1os2 transactivated the expression of Runx3, which in turn induced RUNX3 to positively regulate aromatase (Cyp19a1) expression in mouse ovarian granulosa cells and promote estrogen synthesis. In conclusion, our study indicates that BPA exposure interferes with ERα-regulated lncRNA Fhad1os2 interactions with RUNX3 in pubertal mice, affecting estrogen synthesis in mouse granulosa cells and contributing to premature ovarian maturation in pubertal mice.

Advances in Oocyte Maturation In Vivo and In Vitro in Mammals

The quality and maturation of an oocyte not only play decisive roles in fertilization and embryo success, but also have long-term impacts on the later growth and development of the fetus. Female fertility declines with age, reflecting a decline in oocyte quantity. However, the meiosis of oocytes involves a complex and orderly regulatory process whose mechanisms have not yet been fully elucidated. This review therefore mainly focuses on the regulation mechanism of oocyte maturation, including folliculogenesis, oogenesis, and the interactions between granulosa cells and oocytes, plus in vitro technology and nuclear/cytoplasm maturation in oocytes. Additionally, we have reviewed advances made in the single-cell mRNA sequencing technology related to oocyte maturation in order to improve our understanding of the mechanism of oocyte maturation and to provide a theoretical basis for subsequent research into oocyte maturation.

Ferredoxin 1 regulates granulosa cell apoptosis and autophagy in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS), a common reproductive endocrine disorder in women of reproductive age, causes anovulatory infertility. Increased apoptosis of granulosa cells has been identified as one of the key factors contributing to abnormal follicular development. Ferredoxin 1 (FDX1) encodes a small ferredoxin that is involved in the reduction in mitochondrial cytochromes and the synthesis of various steroid hormones and has the potential to influence the function of granulosa cells. In the present study, we aimed to determine the relationship between FDX1 and follicular granulosa cell function. To this end, we investigated the difference between FDX1 expression in the granulosa cells of 50 patients with PCOS and that of the controls. Furthermore, we sought to elucidate the role and mechanism of FDX1 in PCOS granulosa cells by establishing a mouse PCOS model with dehydroepiandrosterone and KGN (a steroidogenic human granulosa cell-like tumor cell line). The results indicated significant up-regulation of FDX1 in the granulosa cells after androgen stimulation. Knockdown of FDX1 promoted the proliferation of KGN and inhibited apoptosis. Moreover, FDX1 could regulate autophagy by influencing the autophagy proteins ATG3 and ATG7. Our results demonstrated that FDX1 plays a critical role in female folliculogenesis by mediating apoptosis, autophagy, and proliferation. Therefore, FDX1 may be a potential prognostic factor for female infertility.

LncRNA DANCR counteracts premature ovarian insufficiency by regulating the senescence process of granulosa cells through stabilizing the interaction between p53 and hNRNPC

BACKGROUND

Premature ovarian insufficiency (POI) is one of the common women reproductive endocrine diseases which adversely impacts female fertility, but the etiology and pathogenesis still remain elusive. Recently increasing researches focus on the roles of lncRNA in POI. LncRNA DANCR was involved in cell differentiation and multiple cancers. It's highly expressed in ovary while the role of DANCR in POI is still unknown.

RESULTS

Here, we identify a new POI related lncRNA DANCR, which negatively contributes to ovarian granulosa cells aging and follicular atresia. DANCR is proved to be decreasingly expressed in POI patients' granulosa cells. Additionally, Dancr knockout (Dancr^-/-) mice were constructed and characterized with POI phenotypes and fertility decline, compared with Dancr^+/+ mice. Further, in vitro experiments indicated that DANCR knockdown in granulosa cells led to cell aging and series of aging-related changes including proliferation inhibition, cell cycle G1 arrest and DNA damage. Mechanism research revealed DANCR binds with hNRNPC and p53, while DANCR knockdown attenuates the binding of hNRNPC and p53, thus enhancing protein level of p53 and promoting granulosa cells aging significantly.

CONCLUSION

The newly identified lncRNA DANCR inhibits p53-dependent granulosa cells aging by regulating hNRNPC-p53 interaction, and eventually counteracting POI. This provides new insights into the pathogenesis of POI and provides a potential target for future diagnosis and treatment.

DNMT1-mediated lncRNA IFFD controls the follicular development via targeting GLI1 by sponging miR-370

DNA methylation and long noncoding RNAs (lncRNAs) exhibit an indispensable role in follicular development. However, the specific mechanisms regarding lncRNAs mediated by DNA methylation in follicular development remain unclearly. In this study, we found that inhibiting the expression of DNMT1 promoted granulosa cells (GCs) apoptosis to inhibit follicular development. A novel follicular development-associated lncRNA named inhibitory factor of follicular development (IFFD) was mediated by DNMT1 and showed to arrest follicular development by inhibiting GCs proliferation and estrogen (E2) secretion but promoting GCs apoptosis. Mechanistically, the deactivated Cas9-TET1 demonstrated that the hypomethylation in -1261/-1254 region of IFFD promoted the transcription of IFFD by recruiting SP1. IFFD induced the expression of GLI family zinc finger 1 through competitive binding miR-370, thereby up-regulating the expression of CASP3 to promote GCs apoptosis, as well as downregulating the expressions of PCNA and CYP19A1 to inhibit GCs proliferation and E2 secretion. Collectively, DNMT1-mediated IFFD might be a novel target for the regulation of follicular development.

Epg5 deficiency leads to primary ovarian insufficiency due to WT1 accumulation in mouse granulosa cells

Primary ovarian insufficiency (POI), also known as premature ovarian failure, is an ovarian defect in humans characterized by the premature depletion of ovarian follicles before the age of 40. However, the mechanisms underlying POI remain largely unknown. Here, we show that knockout of Epg5 (ectopic P-granules autophagy protein 5 homolog (C. elegans)) results in subfertility in female mice, which exhibit a POI-like phenotype. Single-cell RNA sequencing analysis revealed that the knockout of Epg5 affected the differentiation of granulosa cells (GCs). Further investigation demonstrated that knockout of Epg5 blocks macroautophagic/autophagic flux, resulting in the accumulation of WT1 (WT1 transcription factor), an essential transcription factor for GCs, suggesting WT1 needs to be selectively degraded by the autophagy pathway. We found that the insufficient degradation of WT1 in the antral follicular stage contributes to reduced expression of steroidogenesis-related genes, thereby disrupting GC differentiation. Collectively, our studies show that EPG5 promotes WT1 degradation in GCs, indicating that the dysregulation of Epg5 in GCs can trigger POI pathogenesis.Abbreviations: 3-MA, 3-methyladenine; CHX, cycloheximide; CQ, chloroquine; EPG5, ectopic P-granules autophagy protein 5 homolog (C. elegans); GC, granulosa cell; MAP1LC3/LC3, microtubule-associated protein 1 light chain 3; MII, metaphase II; POI, primary ovarian insufficiency; PB1, polar body 1; SQSTM1/p62, sequestosome 1; WT1, WT1 transcription factor.

miR-450-5p and miR-202-5p Synergistically Regulate Follicle Development in Black Goat

Follicle maturation is a complex biological process governed by numerous factors, and researchers have observed follicle development by studying the proliferation and apoptosis of follicular granulosa cells (GCs). However, the regulatory mechanisms of GCs proliferation and death during follicle development are largely unknown. To investigate the regulatory mechanisms of lncRNAs, mRNAs, and microRNAs, RNA sequencing (RNA-seq) and small RNA-seq were performed on large (>10 mm) and small follicles (<3 mm) of Leizhou black goat during estrus. We discovered two microRNAs, miR-450-5p and miR-202-5p, which can target GCs in goats and may be involved in follicle maturation, and the effects of miR-450-5p and miR-202-5p on ovarian granulosa cell lines were investigated (KGN). Using cell counting kit-8 (CCK-8) assays, 5-Ethynyl-2’-deoxyuridine (EdU) assay and flow cytometry, miR-202-5p overexpression could suppress the proliferation and induce apoptosis of GCs, whereas miR-450-5p overexpression induced the opposite effects. The dual-luciferase reporter assay confirmed that miR-450-5p could directly target the BMF gene (a BCL2 modifying factor), and miR-202-5p targeted the BCL2 gene. A considerable rise in phosphorylated Akt (p-AKT) protein was observed following the downregulation of BMF by miR-450-5p mimics. After BMF gene RNAi therapy, a notable elevation in p-AKT was detected. Mimics of miR-202-5p inhibited BCL2 protein expression, significantly decreasing p-AMPK protein expression. These results imply that during the follicular development in black goats, the miR-450-5p-BMF axis favored GC proliferation on a wide scale, while the miR-202-5p-BCL2 axis triggered GC apoptosis.

Totipotency of miR-184 in porcine granulosa cells

Estradiol (E₂) synthesis, cell proliferation and the apoptosis of porcine granulosa cells (GCs) affect follicular growth and development. The miR-184 level in ovary tissues of Yorkshire × Landrace sows was significantly higher in high-yielding sows than that in low-yielding sows, which was the same as in Yorkshire sows. However, the roles of miR-184 on E₂ granulosa cells (GCs) are still unclear. We found that miR-184 promoted E₂ synthesis and proliferation but inhibited apoptosis in GCs by targeting nuclear receptor subfamily 1 group D member 1 (NR1D1), cyclin dependent kinase inhibitor 1A (P21,CDKN1A) and homeodomain interacting protein kinase 2 (HIPK2) respectively. These findings indicated that miR-184 is a novel key factor that regulates the physiological functions of GCs.

BMP4/SMAD8 signaling pathway regulated granular cell proliferation to promote follicle development in Wanxi white goose

Granular cells proliferation in goose regulated by bone morphogenetic proteins (BMPs) signaling pathway is still unknown. In this experiment, BMPs and their receptor, and receptor activated mothers against decapentaplegic homologs (SMADs) were quantitatively expressed in granular cell layer of pre-hierarchycal and hierarchycal follicles in Wanxi White goose. The screened BMP was then used for construction of overexpressed and knockdown vectors and transfected into granular cells of goose to assess the cell proliferation and apoptosis. Granular cells with BMP-overexpressed were then used for ChIP-Seq analysis to elucidate the molecular mechanism of BMP affecting granular cell proliferation. The results showed that the mRNA expression of BMP4 was significantly expressed in pre-hierarchical follicles, and also highly expressed in hierarchical follicles than other BMPs, while the Ⅰ and Ⅱ type of BMP receptors were expressed in basic level. The mRNA expression of SMAD8 was significantly elevated in pre-hierarchical follicles. Overexpression of BMP4 could promote the proliferation of granular cells and inhibited the expression of BMP4 caused a higher cell apoptosis. ChIP-Seq identified multiple regulatory targets of SMAD4, which were mostly related to cell cycle and lipid metabolism according to the GO and KEGG pathway enrichment. From the five most significant binding motif and quantitative expression verification, the activin membrane binding inhibitor (BAMBI) was down regulated in BMP4 overexpressed granular cells. In conclusion, the BMP4 was highly expressed in granular cells and phosphorylates SMAD8, the activated SMAD8 combined with SMAD4 transfers into nucleus to regulate the expression of BAMBI to promote lipid synthesis.

Overexpression of lncRNA HCP5 in human umbilical cord mesenchymal stem cell-derived exosomes promoted the proliferation and inhibited the apoptosis of ovarian granulosa cells via the musashi RNA-binding protein 2/oestrogen receptor alpha 1 axis

HCP5 has been reported to be downregulated in ovarian granulosa cells (OGCs) and to facilitate cell proliferation. Human umbilical cord mesenchymal stem cell exosome (hucMSCs-exo) treatment can prevent OGCs apoptosis in vitro. However, the functional mechanism of HCP5 and hucMSCs-exo requires further exploration. Fluorescence-activated cell sorting (FACS) was performed to measure the expression of markers related to hucMSCs. The osteogenic and adipogenic potential of hucMSCs was measured by alkaline phosphatase (ALP) and Alizarin red and by oil red-O staining, respectively. Real-time quantitative polymerase chain reaction (RT-qPCR) and Western blotting were used to detect the mRNA and protein levels, respectively. Cell proliferation and apoptosis were measured by Cell Counting Kit-8 (CCK-8) assay, colony formation assay and flow cytometry. The interaction of HCP5/musashi RNA-binding protein 2 (MSI2) and oestrogen receptor alpha 1 (ESR1) mRNA was analysed using RNA pulldown and RIP assays. HucMSCs and exosomes were successfully isolated and identified. HucMSC-derived exosomes promoted the proliferation of OGCs and ESR1 expression and inhibited cell apoptosis. HCP5 overexpression in exosomes further enhanced these effects. MSI2 knockdown led to the opposite results. HCP5 targeted MSI2, and MSI2 knockdown reduced the decreases in HCP5 and ESR1 expression. Mechanistically, HCP5 in HucMSC-derived exosomes promoted ESR1 expression by binding to MSI2, which promoted the proliferation of OGCs.

Efficiency Assessment of Bacterial Cellulose on Lowering Lipid Levels In Vitro and Improving Lipid Metabolism In Vivo

Bacterial cellulose (BC) is well known as a high-performance dietary fiber. This study investigates the adsorption capacity of BC for cholesterol, sodium cholate, unsaturated oil, and heavy metal ions in vitro. Further, a hyperlipidemia mouse model was constructed to investigate the effects of BC on lipid metabolism, antioxidant levels, and intestinal microflora. The results showed that the maximum adsorption capacities of BC for cholesterol, sodium cholate, Pb²⁺ and Cr⁶⁺ were 11.910, 16.149, 238.337, 1.525 and 1.809 mg/g, respectively. Additionally, BC reduced the blood lipid levels, regulated the peroxide levels, and ameliorated the liver injury in hyperlipidemia mice. Analysis of the intestinal flora revealed that BC improved the bacterial community of intestinal microflora in hyperlipidemia mice. It was found that the abundance of Bacteroidetes was increased, while the abundance of Firmicutes and Proteobacteria was decreased at the phylum level. In addition, increased abundance of Lactobacillus and decreased abundance of Lachnospiraceae and Prevotellaceae were obtained at the genus level. These changes were supposed to be beneficial to the activities of intestinal microflora. To conclude, the findings prove the role of BC in improving lipid metabolism in hyperlipidemia mice and provide a theoretical basis for the utilization of BC in functional food.

Gestational exposure to phenanthrene induces follicular atresia and endocrine dyscrasia in F1 adult female

Epidemiological investigations and animal studies demonstrate a significantly positive relationship between polycyclic aromatic hydrocarbons (PAHs) exposure and reproductive disorders. However, few researches are focused on the reproductive toxicity of low-molecular-weight PAHs (number of benzene ring ≤ 3) which occupy a large part of PAHs. Phenanthrene (Phe), a typical low-molecular-weight PAH, is one of the most abundant PAHs detected in foods. In the present study, oral treatment with Phe at a human exposure related level during gestation (60 μg/kg body weight every three days, six times in total) induced reproductive disorders in F1 adult female mice: the number of antral follicles (an immature stage of follicular development) were significantly increased, while the maturation of oocytes was inhibited and aggravated follicular atresia was observed; the serum levels of luteinizing hormone (LH), testosterone and estradiol were significantly reduced; the receptor of follicle-stimulating hormone (FSHR) and aromatase in the ovary were significantly upregulated; transcriptome analysis demonstrated that the phosphatidylinositol 3-kinase and protein kinase B (PI3K/Akt) signal pathway was upregulated, and the calcium signal pathway was disturbed, which probably accounts for the exacerbated atresia of the growing follicles and the excessive consumption of follicles. The reproductive toxicity of low-molecular-weight PAHs could not be neglected.

Concentrated ambient fine particles exposure affects ovarian follicle development in mice

BACKGROUND

Ambient fine particles (PM_2.5) are known to cause various reproductive and developmental diseases. However, the potential mechanisms of PM_2.5 exposure induced female reproductive damage remain unclear.

METHODS

Four weeks old female C57BL/6 J mice were exposed to filtered air (FA, n = 10) or concentrated ambient PM_2.5 (CAP, n = 10) using a versatile aerosol concentration enrichment system. After 9 weeks of the exposure, mice were sacrificed under sevoflurane anesthesia and tissue samples were collected. Immunohistochemical analysis, enzyme-linked immunosorbent assay, quantitative polymerase chain reaction, and RNA-sequencing were performed to analyze the effects of PM_2.5 exposure on follicle development and elucidate its potential mechanisms.

RESULTS

Chronic PM_2.5 exposure resulted in follicular dysplasia. Compared to the FA-exposed group, follicular atresia in the CAP-exposed mice were significantly increased. Further studies confirmed that CAP induced apoptosis in granulosa cells, accompanied by a distortion of hormone homeostasis. In addition, RNA-sequencing data demonstrated that CAP exposure induced the alteration of ovarian gene expressions and was associated with inflammatory response.

CONCLUSIONS

Chronic exposure to CAP can induce follicular atresia, which was associated with hormone modulation and inflammation.

Effect of liver receptor homolog-1 on cell apoptosis and steroid hormone secretion on granulosa cells from Hu sheep

The apoptosis of granulosa cells can result in follicular atresia, a key process in follicle selection and development. The related molecular mechanisms were explored to study the effects of liver receptor homolog-1 (Lrh-1) on apoptosis, sodium-titanium system, and steroid synthesis of granulosa cells from Hu sheep in vitro. After constructing, designing, and synthesizing the Lrh-1 overexpression vector, liposomes were used to transfect Hu sheep granulosa cells. Thereafter, qRT-PCR and Western blot were used to detect the mechanism of Lrh-1 on the titanium system and steroid synthesis of Hu sheep granulosa cells. The overexpression efficiency was determined by fluorescence 48 h after liposome transfection into the Hu sheep granulosa cells in vitro culture. The transfection efficiency was higher, hence providing a basis for subsequent experiments. However, the protein level and transcriptional level of Lrh-1 significantly increased after transfection with Lrh-1 overexpression vector in Hu sheep granulosa cells. We further revealed that after Lrh-1 overexpression in Hu sheep granulosa cells, the expression of the pro-apoptotic gene Bax decreased significantly, while that of the anti-apoptotic gene Bcl-2 increased significantly, as well as the sodium peptide system. Moreover, the expression levels of natriuretic peptide precursor A, B, and C (NPPA, NPPB, NPPC) all showed an upward trend, while the expression levels of steroid synthesis-related genes (P450arom and P450scc) decreased. The above results showed that Lrh-1 overexpression influenced the apoptosis, sodium peptide system, and steroid synthesis.

PPDPF Promotes the Progression and acts as an Antiapoptotic Protein in Non-Small Cell Lung Cancer

Resistance to radiotherapy is frequently observed in the clinic and leads to poor prognosis of non-small cell lung cancer (NSCLC). How to overcome resistance to radiotherapy is a challenge in the treatment of NSCLC. In this study, PPDPF was found to be upregulated in NSCLC tissues and cell lines, and its expression negatively correlated with the overall survival of patients with NSCLC. PPDPF promoted the growth, colony formation and invasion of lung cancer cells. Moreover, knockout of PPDPF inhibited tumorigenesis in the KL (Kras^G12D; LKB1^f/f) mouse model of lung cancer. Additionally, overexpression of PPDPF led to radioresistance in lung cancer cells, and knockdown of PPDPF sensitized lung cancer cells to radiotherapy. Mechanistically, PPDPF interacted with BABAM2 (an antiapoptotic protein) and blocked its ubiquitination by MDM2, thus stabilizing BABAM2 and promoting the radioresistance of lung cancer cells. Our present study suggested PPDPF as a therapeutic target in NSCLC.

NORHA, a novel follicular atresia-related lncRNA, promotes porcine granulosa cell apoptosis via the miR-183-96-182 cluster and FoxO1 axis

BACKGROUND

Follicular atresia has been shown to be strongly associated with a low follicle utilization rate and female infertility, which are regulated by many factors such as microRNAs (miRNAs), which constitute a class of noncoding RNAs (ncRNAs). However, little is known about long noncoding RNAs (lncRNAs), which constitute another ncRNA family that regulate follicular atresia.

RESULTS

A total of 77 differentially expressed lncRNAs, including 67 upregulated and 10 downregulated lncRNAs, were identified in early atretic follicles compared to healthy follicles by RNA-Sequencing. We characterized a noncoding RNA that was highly expressed in atretic follicles (NORHA). As an intergenic lncRNA, NORHA was one of the upregulated lncRNAs identified in the atretic follicles. To determine NORHA function, RT-PCR, flow cytometry and western blotting were performed, and the results showed that NORHA was involved in follicular atresia by influencing GC apoptosis with or without oxidative stress. To determine the mechanism of action, bioinformatics analysis, luciferase reporter assay and RNA immunoprecipitation assay were performed, and the results showed that NORHA acted as a 'sponge', that directly bound to the miR-183-96-182 cluster, and thus prevented its targeted inhibition of FoxO1, a major sensor and effector of oxidative stress.

CONCLUSIONS

We provide a comprehensive perspective of lncRNA regulation of follicular atresia, and demonstrate that NORHA, a novel lncRNA related to follicular atresia, induces GC apoptosis by influencing the activities of the miR-183-96-182 cluster and FoxO1 axis.

SMAD4-induced knockdown of the antisense long noncoding RNA BRE-AS contributes to granulosa cell apoptosis

Antisense long noncoding RNAs (AS-lncRNAs), a sub-class of lncRNAs, are transcribed in the opposite direction from their overlapping protein-coding genes and are implicated in various physiological and pathological processes. However, their role in female reproduction remains largely unknown. Here, we report that BRE-AS, an AS-lncRNA transcript from intron 10 of the protein-coding gene BRE, is involved in granulosa cell (GC) apoptosis. Based on our previous RNA sequencing data, we identified 28 AS-lncRNAs as important in the initiation of porcine follicular atresia, with BRE-AS showing the most significant upregulation in early atretic follicles. In this study, gain- and loss-of-function assays demonstrated that BRE-AS induces early apoptosis in GCs. Mechanistically, BRE-AS acts in cis to suppress the expression of BRE, an anti-apoptotic factor, via direct interaction with the pre-mRNA transcript of the latter, inducing increased GC apoptosis. Notably, we also found that BRE-AS was upregulated in SMAD4-silenced GCs. SMAD4 was identified as a transcriptional repressor of BRE-AS because it inhibits BRE-AS expression and BRE-AS-mediated GC apoptosis. In conclusion, we not only identified a novel AS-lncRNA related to the early apoptosis of GCs and initiation of follicular atresia but also described a novel regulatory pathway, SMAD4/BRE-AS/BRE, coordinating GC function and female fertility.

Joint Genome-Wide Association Analyses Identified 49 Novel Loci For Age at Natural Menopause

BACKGROUND

Age at natural menopause (ANM) is an important index for women's health. Either early or late ANM is associated with a series of adverse outcomes later in life. Despite being an inheritable trait, its genetic determinant has not yet been fully understood.

METHODS

Aiming to better characterize the genetic architecture of ANM, we conducted genome-wide association study (GWAS) meta-analyses in European-specific as well as trans-ancestry samples by using GWAS summary statistics from the following 3 large studies: the Reproductive Genetics Consortium (ReproGen; N = 69 626), the UK Biobank cohort (UKBB; N = 111 593) and the BioBank Japan Project (BBJ; N = 43 861), followed by a series of bioinformatical assessments and functional annotations.

RESULTS

By integrating the summary statistics from the 3 GWAS of up to 225 200 participants, this largest meta-analysis identified 49 novel loci and 3 secondary signals that were associated with ANM at the genome-wide significance level (P < 5 × 10-8). No population specificity or heterogeneity was observed at most of the associated loci. Functional annotations prioritized 90 candidate genes at the newly identified loci. Among the 26 traits that were genetically correlated with ANM, hormone replacement therapy (HRT) exerted a causal relationship, implying a causal pattern by which HRT was determined by ANM.

CONCLUSION

Our findings improved our understanding of the etiology of female menopause, as well as shed light on potential new therapies for abnormal menopause.

PATL2 regulated the apoptosis of ovarian granulosa cells in patients with PCOS

AIM

PCOS often showed abnormal follicular development. Previous studies have found that the increased apoptosis of granulosa cells (GCs) is one of the key factors leading to follicular dysplasia. It has been found that the decrease or deletion of PATL2 function can significantly inhibit the development and maturation of human oocytes. We found that PATL2 was also expressed in human ovarian GCs, suggesting that PATL2 may be involved in the regulation of related biological events in GCs. This study aims to explore the function of PATL2 on regulation of GCs apoptosis, and the potential role of PATL2 in the development of PCOS-related abnormal follicles.

MATERIALS AND METHODS

The follicular GCs of PCOS patients and normal ovulating female patients were collected. Moreover, human granular cell line (KGN) was used for in vitro experiments.

RESULTS

(1) The maturation rate and fertilization rate of oocytes in the PCOS group were significantly lower than those in the normal control group (p＜0.05). (2) Flow cytometry and TUNEL staining showed that the apoptosis level of GCs in the PCOS group was significantly increased. (3) Immunofluorescence and Western Blot showed that the PATL2 expression level of GCs in the PCOS group was significantly reduced. (4) Knocking down the expression of PATL2 by siRNA significantly prevented the apoptosis of GCs.

CONCLUSIONS

Reduced PATL2 could resulted in the increased apoptosis level of ovarian GCs, which might be closely related to the occurrence and development of abnormal follicles in PCOS.

PAQR7: An intermediary mediating nongenomic progesterone action in female reproductive tissue

Progestin and adipoQ receptor 7 (PAQR7) as an indispensable member of membrane progestin receptors in the Progestin and adipoQ receptor (PAQR) family that mediates nongenomic progesterone actions, initiated rapidly at the cell surface. Previous research demonstrated the distribution of PAQR7, which was mainly expressed in reproductive tissues, including ovary and testis. In the male reproductive system, PAQR7 is involved in progestin-induced sperm hypermotility. However, reports studying PAQR7 in female reproductive tissue mainly concentrate on oocyte maturation in fish, its expression in the ovary and gestational tissue, and regulation of uterine functions in mammals. Despite recent advances, many aspects of progestin signaling through PAQR7 are still unclear, especially in female reproductive tissue. Therefore, we reveal the structure and characteristics of PAQR7 and conclude the putative progestin-induced action mediated by PAQR7 in female reproductive tissue, such as the development of ovarian follicles, apoptosis of granulosa cells, oocyte maturation, and development of certain diseases, among others, to review the function of PAQR7 in the female reproductive system in detail.

DNA methylation mediated RSPO2 to promote follicular development in mammals

In female mammals, the proliferation, apoptosis, and estradiol-17β (E2) secretion of granulosa cells (GCs) have come to decide the fate of follicles. DNA methylation and RSPO2 gene of Wnt signaling pathway have been reported to involve in the survival of GCs and follicular development. However, the molecular mechanisms for how DNA methylation regulates the expression of RSPO2 and participates in the follicular development are not clear. In this study, we found that the mRNA and protein levels of RSPO2 significantly increased during follicular development, but the DNA methylation level of RSPO2 promoter decreased gradually. Inhibition of DNA methylation or DNMT1 knockdown could decrease the methylation level of CpG island (CGI) in RSPO2 promoter and upregulate the expression level of RSPO2 in porcine GCs. The hypomethylation of -758/-749 and -563/-553 regions in RSPO2 promoter facilitated the occupancy of transcription factor E2F1 and promoted the transcriptional activity of RSPO2. Moreover, RSPO2 promoted the proliferation of GCs with increasing the expression level of PCNA, CDK1, and CCND1 and promoted the E2 secretion of GCs with increasing the expression level of CYP19A1 and HSD17B1 and inhibited the apoptosis of GCs with decreasing the expression level of Caspase3, cleaved Caspase3, cleaved Caspase8, cleaved Caspase9, cleaved PARP, and BAX. In addition, RSPO2 knockdown promoted the apoptosis of GCs, blocked the development of follicles, and delayed the onset of puberty with decreasing the expression level of Wnt signaling pathway-related genes (LGR4 and CTNNB1) in vivo. Taken together, the hypomethylation of -758/-749 and -563/-553 regions in RSPO2 promoter facilitated the occupancy of E2F1 and enhanced the transcription of RSPO2, which further promoted the proliferation and E2 secretion of GCs, inhibited the apoptosis of GCs, and ultimately ameliorated the development of follicles through Wnt signaling pathway. This study will provide useful information for further exploration on DNA-methylation-mediated RSPO2 pathway during follicular development.

miR-130b-3p is high-expressed in polycystic ovarian syndrome and promotes granulosa cell proliferation by targeting SMAD4

BACKGROUND

Being one of the most prevalent metabolic and endocrine disorders, Polycystic Ovary Syndrome (PCOS) has been proven to be associated with microRNA-130b-3p (miR-130b-3p). However, the exact role played by miR-130b-3p in the pathogenesis and progression of PCOS remains unknown. Thus, this article is focused on elucidating the function of miR-130b-3p in the pathogenesis of PCOS.

METHODS

The expression levels of miR-130b-3p and SMAD4 in tissues and cells responsible for the development of PCOS were determined by RT-qPCR and western blot. A miR-130b-3p mimic/inhibitor or si-SMAD4 were transfected into KGN cells. The cell viability was detected by CCK-8 and EDU methods. The activity of caspase-3 was measured by caspase-3 analysis. Subsequently, apoptosis and the cell cycle were measured via flow cytometry. The correlation between SMAD4 and miR-130b-3p was confirmed using an RNA pull-down assay and a dual luciferase reporter system assay.

RESULTS

MiR-130b-3p was upregulated in the KGN cells and ovarian granulosa cells (GCs) of PCOS patients. It was found that miR-130b-3p overexpression or SMAD4 silencing can promote KGN cell proliferation and positive EDU rates, induce S phase arrest, inhibit apoptosis and caspase-3 activity. On the other hand, miR-130b-3p inhibitors reduce KGN cell proliferation, inhibit apoptosis and reverse the effect of si-SMAD4.

CONCLUSION

MiR-130b-3p directly interacts with SMAD4 to induce KGN cell proliferation, inhibit apoptosis, suggesting that miR-130b-3p expression is positively correlated with the development of PCOS. This may serve as new evidence for the abnormal proliferation of GCs in PCOS.

Effects of Tannic Acid on Antioxidant Activity and Ovarian Development in Adolescent and Adult Female Brandt's Voles

It is well known that tannins can influence the reproduction of animals, but there is little research published to elucidate the mechanics of this phenomenon. The purpose of this study was to investigate the role of antioxidation in the influence of tannic acid on the ovarian development of Brandt's voles (Lasiopodomys brandtii), which is a species of prairie animal that feeds on plants containing tannins. Postnatal 4-week-old female Brandt's voles were treated with 0 (control), 0.3% (low dose), or 0.6% (high dose) tannic acid for 4 or 9 weeks (i.e., when they reached puberty [8 weeks] or sexual maturity [13 weeks], respectively). The results showed that in both adolescent and adult Brandt's voles, firstly, treatment with tannic acid produced a higher ovary coefficient (ratio of the weight of ovaries to body weight), a greater proportion of mature follicles, and an increased follicular diameter. Secondly, tannic acid increased the serum contents of luteinizing hormone, follicle-stimulating hormone, and serum estradiol. Thirdly, tannic acid elevated the levels of antioxidant enzymes (superoxide dismutase, glutathione peroxidase, and catalase) and reduced the level of malondialdehyde. Therefore, it is suggested that tannic acid may promote the ovarian development of female Brant's voles by enhancing their antioxidant capacity.

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.

Transcriptomic Data Analyses Reveal That Sow Fertility-Related lincRNA NORFA Is Essential for the Normal States and Functions of Granulosa Cells

NORFA, the first lincRNA associated with sow fertility, has been shown to control granulosa cell (GC) functions and follicular atresia. However, the underlying mechanism is not fully understood. In this study, RNA-seq was performed and we noticed that inhibition of NORFA led to dramatic transcriptomic alterations in porcine GCs. A total of 1,272 differentially expressed transcripts were identified, including 1167 DEmRNAs and 105 DEmiRNAs. Furthermore, protein–protein interaction, gene-pathway function, and TF–miRNA–mRNA regulatory networks were established and yielded four regulatory modules with multiple hub genes, such as AR, ATG5, BAK1, CENPE, NR5A1, NFIX, WNT5B, ssc-miR-27b, and ssc-miR-126. Functional assessment showed that these hub DEGs were mainly enriched in TGF-β, PI3K-Akt, FoxO, Wnt, MAPK, and ubiquitin pathways that are essential for GC states (apoptosis and proliferation) and functions (hormone secretion). In vitro, we also found that knockdown of NORFA in porcine GCs significantly induced cell apoptosis, impaired cell viability, and suppressed 17β-estradiol (E2) synthesis. Notably, four candidate genes for sow reproductive traits (INHBA, NCOA1, TGFβ-1, and TGFBR2) were also identified as potential targets of NORFA. These findings present a panoramic view of the transcriptome in NORFA-reduced GCs, highlighting that NORFA, a candidate lincRNA for sow fertility, is crucial for the normal states and functions of GCs.

MicroRNA-874-3p promotes testosterone-induced granulosa cell apoptosis by suppressing HDAC1-mediated p53 deacetylation

MicroRNA (miR)-874-3p is a newly identified miRNA that is involved in several pathological processes, including cancer, myocardial infarction, bone formation and erectile dysfunction. However, the role of miR-874-3p in polycystic ovary syndrome (PCOS) and granulosa cell (GC) apoptosis is not completely understood. The present study investigated the expression profile of miR-874-3p in PCOS by reverse transcription- quantitative PCR and the GC apoptosis by flow cytometry analysis. miR-874-3p expression was significantly upregulated in GCs isolated from patients with PCOS compared with patients without PCOS. In addition, miR-874-3p expression was positively correlated with GC apoptosis and testosterone levels in both patients with PCOS and patients without PCOS. Therefore, the present study also aimed to investigate the effects of miR-874-3p on testosterone-induced GC apoptosis. Compared with vehicle-treated GCs, miR-874-3p expression levels were significantly increased in testosterone-treated GCs, which was inhibited by the androgen receptor antagonist flutamide. GCs were transfected with either the miR-874-3p mimic or a miR-874-3p inhibitor. Compared with the control group, miR-874-3p mimic significantly enhanced GC apoptosis, whereas miR-874-3p inhibitor significantly decreased GC apoptosis. Moreover, histone deacetylase (HDAC) activity and HDAC1 expression levels were decreased in testosterone-treated GCs compared with vehicle-treated GCs. HDAC1 overexpression significantly attenuated the proapoptotic effects of testosterone. Additionally, miR-874-3p mimic and inhibitor significantly decreased and increased HDAC1 expression levels, respectively, compared with the control group. miR-874-3p inhibitor failed to attenuate HDAC1 overexpression-induced GC apoptosis. Furthermore, compared with the control group, testosterone treatment notably increased p53 expression and acetylation. Compared with the control group, western blotting analysis showed that miR-874-3p mimic notably increased p53 expression and acetylation, whereas miR-874-3p inhibitor markedly decreased p53 expression and acetylation. However, miR-874-3p inhibitor did not further decrease p53 acetylation and expression in cell overexpressing HDAC1. Collectively, the results of the present study indicated that miR-874-3p was upregulated in PCOS and promoted testosterone-induced GC apoptosis by suppressing HDAC1-mediated p53 deacetylation. Therefore, the present study improved the current understanding of the pathogenesis of PCOS and GC apoptosis.

Regulation of Female Folliculogenesis by Tsp1a in Nile Tilapia (Oreochromis niloticus)

TSP1 was reported to be involved in multiple biological processes including the activation of TGF-β signaling pathways and the regulation of angiogenesis during wound repair and tumor growth, while its role in ovarian folliculogenesis remains to be elucidated. In the present study, Tsp1a was found to be expressed in the oogonia and granulosa cells of phase I to phase IV follicles in the ovaries of Nile tilapia by immunofluorescence. tsp1a homozygous mutants were generated by CRISPR/Cas9. Mutation of tsp1a resulted in increased oogonia, reduced secondary growth follicles and delayed ovary development. Expression of the cell proliferation marker PCNA was significantly up-regulated in the oogonia of the mutant ovaries. Furthermore, transcriptomic analysis revealed that expressions of DNA replication related genes were significantly up-regulated, while cAMP and MAPK signaling pathway genes which inhibit cell proliferation and promote cell differentiation were significantly down-regulated. In addition, aromatase (Cyp19a1a) expression and serum 17β-estradiol (E2) concentration were significantly decreased in the mutants. These results indicated that lacking tsp1a resulted in increased proliferation and inhibited differentiation of oogonia, which in turn, resulted in increased oogonia, reduced secondary growth follicles and decreased E2. Taken together, our results indicated that tsp1a was essential for ovarian folliculogenesis in Nile tilapia.

Long noncoding RNA HCP5 participates in premature ovarian insufficiency by transcriptionally regulating MSH5 and DNA damage repair via YB1

The genetic etiology of premature ovarian insufficiency (POI) has been well established to date, however, the role of long noncoding RNAs (lncRNAs) in POI is largely unknown. In this study, we identified a down-expressed lncRNA HCP5 in granulosa cells (GCs) from biochemical POI (bPOI) patients, which impaired DNA damage repair and promoted apoptosis of GCs. Mechanistically, we discovered that HCP5 stabilized the interaction between YB1 and its partner ILF2, which could mediate YB1 transferring into the nucleus of GCs. HCP5 silencing affected the localization of YB1 into nucleus and reduced the binding of YB1 to the promoter of MSH5 gene, thereby diminishing MSH5 expression. Taken together, we identified that the decreased expression of HCP5 in bPOI contributed to dysfunctional GCs by regulating MSH5 transcription and DNA damage repair via the interaction with YB1, providing a novel epigenetic mechanism for POI pathogenesis.

Amh regulate female folliculogenesis and fertility in a dose-dependent manner through Amhr2 in Nile tilapia

In the present study, Amh was found to be abundantly expressed in the granulosa cells of the primary growth follicles, and Amhr2 in the granulosa cells, oogonia and phase I oocytes in tilapia by immunohistochemistry. In addition, Amh and Amhr2 were also found to be expressed in the brain and pituitary. Heterozygous mutation of either amh or amhr2 resulted in increased primary growth follicles and decreased fertility, and homozygous mutation resulted in hypertrophic ovaries with significantly increased primary follicles and failed transition from primary to vitellogenic follicles. Expression of gnrh3 in the brain, fsh and lh in the pituitary and serum E2 concentration were significantly decreased in both mutants. Significantly increased apoptosis of follicle cells was observed in both mutants. However, administration of E2 failed to rescue the folliculogenesis defects of the mutants. Our results suggested that Amh acts in a dose-dependent manner by binding Amhr2 in tilapia.

MicroRNA-200b and microRNA-200c are up-regulated in PCOS granulosa cell and inhibit KGN cell proliferation via targeting PTEN

BACKGROUND

Polycystic ovary syndrome (PCOS) is one of the most common endocrine metabolic disorders characterized by hyperandrogenism, polycystic ovaries and ovulatory dysfunction. Several studies have reported that the aberrant expression of miRNAs contributes a lot to disordered folliculogenesis in PCOS, though the role and underlying mechanism of microRNA-200b (miR-200b) and microRNA-200c (miR-200c) in the development of PCOS remain unclear.

METHODS

The expression of miR-200b in granulosa cells (GCs) derived from 90 PCOS patients and 70 controls was analyzed by using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Granulosa-like tumor cell line (KGN) was cultured for cell counting kit-8 (CCK-8) assays after over-expression of miR-200b, miR-200c or knockdown phosphatase and tensin homolog (PTEN). TargetScan was used to identify the potential targets of miR-200b and miR-200c, which was further verified by qRT-PCR, western blot and luciferase assays.

RESULTS

Significantly increased expression of miR-200b was observed in PCOS patients compared with the controls. Moreover, over-expression of miR-200b and miR-200c inhibited the proliferation of KGN cells. In addition, our results verified that miR-200b and miR-200c directly targeted PTEN, knockdown of which suppressed KGN cells proliferation.

CONCLUSION

Our findings demonstrate that miR-200b and miR-200c suppress the proliferation of KGN cells by targeting PTEN, and this might provide new evidence for abnormal proliferation of GCs in PCOS.

Di-n-butyl phthalate epigenetically induces reproductive toxicity via the PTEN/AKT pathway

Di-n-butyl phthalate (DBP) is a kind of ubiquitous chemical linked to hormonal disruptions that affects male reproductive system. However, the mechanism of DBP-induced germ cells toxicity remains unclear. Here, we demonstrate that DBP induces reduction of proliferation, increase of apoptosis and DNA damage dependent on the PTEN/AKT pathway. Mechanistically, DBP decreases PTEN promoter methylation and increases its transcriptional activity, leading to increased PTEN expression. Notably, DNMT3b is confirmed as a target of miR-29b and miR-29b-mediated status of PTEN methylation is involved in the effects of DBP treatment. Meanwhile, DBP decreases AKT pathway expression via increasing PTEN expression. In addition, the fact that DBP decreases the sperm number and the percentage of motile and progressive sperm is associated with downregulated AKT pathway and sperm flagellum-related genes. Collectively, these findings indicate that DBP induces aberrant PTEN demethylation, leading to inhibition of the AKT pathway, which contributes to the reproductive toxicity.

microRNA-203 promotes proliferation, differentiation, and migration of osteoblasts by upregulation of Msh homeobox 2

Despite the improvements in fracture healing, about 10% of patients undergo abnormal healing. As a tumor suppressor, upregulation of microRNA (miR)-203 has been observed in osteogenic differentiation. Herein, we aimed to explore the functional role of miR-203 in osteoblasts as well as the underlying mechanisms. The expression of miR-203 in MC3T3-E1 cells that underwent osteogenic differentiation was determined by quantitative reverse transcription PCR (qRT-PCR). The effects of aberrantly expressed miR-203 on cell viability, migration, and expressions of proteins associated with proliferation, migration, and osteogenic differentiation were measured by using a Cell Counting Kit-8 assay, Transwell cell migration assay, and western blot/qRT-PCR, respectively. The possible downstream factor of miR-203 was subsequently studied. Finally, involvements of the mitogen-activated protein kinase (MAPK)/activator of transcription (STAT) pathways were assessed by western blot. We found that the miR-203 level was increased in osteogenic differentiation of MC3T3-E1 cells with increasing duration time (28th day, p < 0.001). After cell transfection, we interestingly found that miR-203 overexpression could increase cell viability (p < 0.05), promote proliferation, migration (p < 0.05), and osteogenic differentiation, and upregulate Msh homeobox 2 (Msx2) expression. Furthermore, Msx2 knockdown was proved to abrogate the effects of miR-203 overexpression on MC3T3-E1 cells. Finally, phosphorylated levels of key kinases in the MAPK/STAT pathways were increased by miR-203 overexpression via upregulating Msx2 expression. In conclusion, miR-203 overexpression promoted proliferation, migration, and osteogenic differentiation of MC3T3-E1 cells through upregulating Msx2 along with activation of the MAPK/STAT pathways.

PM2.5 induces male reproductive toxicity via mitochondrial dysfunction, DNA damage and RIPK1 mediated apoptotic signaling pathway

Recent years, air pollution has been a serious problem, and PM_2.5 is the main air particulate pollutant. Studies have investigated that PM_2.5 is a risky factor to the deterioration of semen quality in males. But, the related mechanism is still unclear. To explore the effect of PM_2.5, Sprague Dawley (SD) rats were exposed to PM_2.5 (0, 1.8, 5.4 and 16.2mg/kg.bw.) through intratracheal instillation. The exposure was performed once every 3days and continued for 30days. In vitro, GC-2spd cells were treated using 0, 50, 100, 200μg/mL PM_2.5 for 24h. The data showed that sperm relative motility rates and density were remarkably decreased, while sperm malformation rates were significantly increased with exposure to the PM_2.5. The expression of Fas/FasL/RIPK1/FADD/Caspase-8/Caspase-3 and the level of 8-OHdG expression in testes were significantly increased after exposure to PM_2.5. Additionally, in vitro the results showed that PM_2.5 inhibited cell viability, increased the release of lactate dehydrogenase (LDH) by increasing reactive oxygen species (ROS) level. And ROS induced-DNA damage led to cell cycle arrest at G0/G1 phases and proliferation inhibition. Similar to the vivo study, the expressions of Fas/FasL/RIPK1/FADD/Caspase-8/Caspase-3 in GC-2spd cells were significantly increased after exposure to PM_2.5 for 24-h. In addition, PM_2.5 decreased the levels of ATP by impairing mitochondria structures, which led to energy metabolism obstruction resulted in the decrease of sperm motility. The above three aspects together resulted in the decrease in sperm quantity and quality.

Silica nanoparticle exposure inducing granulosa cell apoptosis and follicular atresia in female Balb/c mice

Given that the effects of ultrafine fractions (< 0.1 μm) on reproductive diseases are gaining attention, this study aimed to explore the influence of silica nanoparticle (SiNP)-induced female reproductive dysfunction. In this study, 80 female mice were randomly divided into four groups including a control group and three concentrations of SiNP groups (7, 21, 35 mg/kg). Mice were exposed to the vehicle control and silica nanoparticles by tracheal perfusion every 3 days a total of five times in 15 days. Then, half of the mice in each group were sacrificed on 15 and 30 days after the first dose, respectively. Our findings indicated that SiNPs can result in ovarian damage, cause an imbalance of sex hormones, increase the number of atretic and primary follicles, and induce oxidative stress and DNA strand breaks in ovary by day 15. The protein expressions of ATM, CHK-2, P53, E2F1, P73, BAX, Caspase-9, and Caspase-3 were significantly increased, while expressions of RAD51 were down-regulated after SiNP exposure by days 15. Estradiol increased, while progesterone increased in low dose and decreased in high dose after SiNP exposure by 15 days. However, these changes were recovered by 30 days. The results suggest that SiNPs can cause reversible damage to follicles in mice. SiNPs could primarily cause DNA damage and DNA damage response through oxidative stress, while DNA damage repair failure because of severe DNA damage activated the mitochondrial apoptosis pathway and therefore resulted in apoptosis of granulosa cell. In addition, the disorder of reproductive endocrine function caused by SiNPs could be another reason for SiNP-induced reproductive dysfunction in mice. These events in turn induce the follicles to undergo atresia.

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.