SFRP4 promotes autophagy and blunts FSH responsiveness through inhibition of AKT signaling in ovarian granulosa cells.

BACKGROUND: Secreted frizzled-related proteins (SFRPs) comprise a family of WNT signaling antagonists whose roles in the ovary are poorly understood. Sfrp4-null mice were previously found to be hyperfertile due to an enhanced granulosa cell response to gonadotropins, leading to decreased antral follicle atresia and enhanced ovulation rates. The present study aimed to elucidate the mechanisms whereby SFRP4 antagonizes FSH action. METHODS: Primary cultures of granulosa cells from wild-type mice were treated with FSH and/or SFRP4, and effects of treatment on gene expression were evaluated by RT-qPCR and RNAseq. Bioinformatic analyses were conducted to analyse the effects of SFRP4 on the transcriptome, and compare them to those of FSH or a constitutively active mutant of FOXO1. Additional granulosa cell cultures from wild-type or Sfrp4-null mice, some pretreated with pharmacologic inhibitors of specific signaling effectors, were used to examine the effects of FSH and/or SFRP4 on signaling pathways, autophagy and apoptosis by western blotting and TUNEL. RESULTS: Treatment of cultured granulosa cells with recombinant SFRP4 was found to decrease basal and FSH-stimulated mRNA levels of FSH target genes. Unexpectedly, this effect was found to occur neither via a canonical (CTNNB1-dependent) nor non-canonical WNT signaling mechanism, but was found to be GSK3ß-dependent. Rather, SFRP4 was found to antognize AKT activity via a mechanism involving AMPK. This lead to the hypophosphorylation of FOXO1 and a decrease in the expression of a portion of the FSH and FOXO1 transcriptomes. Conversely, FSH-stimulated AMPK, AKT and FOXO1 phosphorylation levels were found to be increased in the granulosa cells of Sfrp4-null mice relative to wild-type controls. SFRP4 treatement of granulosa cells also induced autophagy by signaling via AKT-mTORC1-ULK1, as well as apoptosis. CONCLUSIONS: This study identifies a novel GSK3ß-AMPK-AKT signaling mechanism through which SFPR4 antagonizes FSH action, and further identifies SFRP4 as a novel regulator of granulosa cell autophagy. These findings provide a mechanistic basis for the phenotypic changes previously observed in Sfrp4-null mice, and broaden our understanding of the physiological roles of WNT signaling processes in the ovary.

Copper mediated follicular atresia: Implications for granulosa cell death.

3-nitropropanoic acid is a potent oxidative stress inducer that is conventionally regarded as a regulator of follicular atresia by regulating granulosa cells (GCs) death through the apoptosis pathway. There has been no research investigating the impact of copper metal overload induced Cuproptosis in ovarian GCs as a factor contributing to hindered follicular development.To elucidate whether 3-NP-induced oxidative stress plays a contributory role in promoting Cuproptosis, and discuss the role of Cuproptosis in the development of ovarian follicles.We conducted an analysis of cuproptosis occurrence in murine GCs and C57BL/6 J mice under the influence of 3-NP and 3-NP with added exogenous copper.The results revealed that 3-NP serving as a robust facilitator of exogenous copper uptake by upregulating the expression of copper transporter 1 (CTR1). In turn, culminated in the accumulation of intracellular copper within mouse granulosa cells (mGCs). Furthermore, 3-NP promoted mitochondrial permeability transition pore opening and concurrently reduced the stability of lipoic acid proteins. These actions collectively induced the oligomerization of Dihydrolipoamide S-Acetyltransferase (DLAT), ultimately leading to cuproptosis in GCs and consequent follicular atresia. Heavy metal copper and fungal decomposition product 3-NP, induce ovarian atresia via cuproptosis, modulating the reproductive performance of female animals.

Granulosa cell insight: unraveling the potential of menstrual blood-derived stem cells and their exosomes on mitochondrial mechanisms in polycystic ovary syndrome (PCOS).

BACKGROUND: Polycystic ovary syndrome (PCOS) presents a significant challenge in women's reproductive health, characterized by disrupted folliculogenesis and ovulatory dysfunction. Central to PCOS pathogenesis are granulosa cells, whose dysfunction contributes to aberrant steroid hormone production and oxidative stress. Mitochondrial dysfunction emerges as a key player, influencing cellular energetics, oxidative stress, and steroidogenesis. This study investigates the therapeutic potential of menstrual blood-derived stem cells (MenSCs) and their exosomes in mitigating mitochondrial dysfunction and oxidative stress in PCOS granulosa cells. METHODS: Using a rat model of PCOS induced by letrozole, granulosa cells were harvested and cultured. MenSCs and their exosomes were employed to assess their effects on mitochondrial biogenesis, oxidative stress, and estrogen production in PCOS granulosa cells. RESULTS: Results showed diminished mitochondrial biogenesis and increased oxidative stress in PCOS granulosa cells, alongside reduced estrogen production. Treatment with MenSCs and their exosomes demonstrated significant improvements in mitochondrial biogenesis, oxidative stress levels, and estrogen production in PCOS granulosa cells. Further analysis showed MenSCs' superior efficacy over exosomes, attributed to their sustained secretion of bioactive factors. Mechanistically, MenSCs and exosomes activated pathways related to mitochondrial biogenesis and antioxidative defense, highlighting their therapeutic potential for PCOS. CONCLUSIONS: This study offers insights into granulosa cells mitochondria's role in PCOS pathogenesis and proposes MenSCs and exosomes as a potential strategy for mitigating mitochondrial dysfunction and oxidative stress in PCOS. Further research is needed to understand underlying mechanisms and validate clinical efficacy, presenting promising avenues for addressing PCOS complexity.

Zishen Qingre Lishi Huayu Recipe May Ameliorate the Symptoms of PCOS Model Rats via Alleviating Systemic and Ovarian Inflammation.

BACKGROUND: Zishen Qingre Lishi Huayu recipe (ZQLHR) has shown significant therapeutic effects in treating sex hormone levels and follicular developmental disorders in patients with polycystic ovary syndrome (PCOS). However, little is known about the potential mechanisms of its treatment. METHODS: Dehydroepiandrosterone and a high-fat diet induced the PCOS model rat. The serum of rats was collected to detect the levels of sex hormones and inflammatory cytokines by enzyme-linked immunosorbent assay, and the ovaries were collected for ovarian histopathology and qPCR assay to detect the levels of inflammatory cytokines in ovarian tissues. Granulosa cells (GCs) were collected for western blot assay to detect of IL-1ß, IL-6R, and LOX protein expression levels. RESULTS: ZQLHR could reduce body weight, regulate estrous cycles, and improve serum sex hormone levels, follicular development, and insulin resistance (IR) in PCOS model rats. In addition, ZQLHR treatment improved the levels of inflammatory cytokines in serum and ovary, and regulated the protein expression of IL-6R, IL-1ß, and LOX in GCs of PCOS model rats. The results showed that the HOMA-IR index increased with the increasing levels of IL-6, IL-1ß, and CRP, and decreased with the increased IL-10. CONCLUSION: This study reveals that the treatment of endocrine disorders and ovulation disorders in PCOS with ZQLHR may be closely related to the improvement of systemic and ovarian inflammation in PCOS patients, as well as the inhibition of IL-6R, IL-1ß, and LOX expression in GCs, which reemphasizes the role of reducing chronic inflammatory states in the treatment of PCOS. Moreover, this study reemphasizes the correlation between multiple inflammatory mediators and IR.

Granulosa cells provide transcriptomic information on ovarian follicle dynamics in southern white rhinoceros.

Much remains unknown about the reproductive physiology of southern white rhinoceros (SWR) and the effect of ovarian stimulation prior to ovum pickup (OPU) have not been fully elucidated. Granulosa cells (GC) provide valuable insight into follicle growth and oocyte maturation status. The goals of this study were to evaluate transcriptomic changes in GC from three stages of follicle development and to identify biomarkers possibly associated with follicular growth and maturation as a result of ovarian stimulation. GC collected from SWRs following OPU were assigned stages based upon follicle size. Total RNA was isolated, and cDNA libraries were prepared and sequenced on a NovaSeq 6000. All bioinformatics analyses were performed utilizing the Galaxy web platform. Reads were aligned to CerSimCot1.0, and the manual curation was performed with EquCab3.0. Overall, 39,455 transcripts (21,612 genes) were identified across follicle stages, and manual curation yielded a 61% increase in gene identification from the original annotation. Granulosa cells from preovulatory follicles expressed the highest number of unique transcripts. The following seven biomarkers were determined based upon cluster analysis and patterns of expression: COL1A1, JMY, FBXW11, NRG1, TMPO, MACIR and COL4A1. These data can be used to potentially evaluate the effects of different ovarian stimulation protocols on follicle dynamics, improve OPU results, and support conservation efforts in this species.

The epithelial Na+ channel (ENaC) in ovarian granulosa cells modulates Ca2+ mobilization and gonadotrophin signaling for estrogen homeostasis and female fertility.

Ovarian granulosa cells are essential to gonadotrophin-regulated estrogen production, female cycle maintenance and fertility. The epithelial Na+ channel (ENaC) is associated with female fertility; however, whether and how it plays a role in ovarian cell function(s) remained unexplored. Here, we report patch-clamp and Na+ imaging detection of ENaC expression and channel activity in both human and mouse ovarian granulosa cells, which are promoted by pituitary gonadotrophins, follicle stimulating hormone (FSH) or luteinizing hormone (LH). Cre-recombinase- and CRISPR-Cas9-based granulosa-specific knockout of ENaC α subunit (Scnn1a) in mice resulted in failed estrogen elevation at early estrus, reduced number of corpus luteum, abnormally extended estrus phase, reduced litter size and subfertility in adult female mice. Further analysis using technologies including RNA sequencing and Ca2+ imaging revealed that pharmacological inhibition, shRNA-based knockdown or the knockout of ENaC diminished spontaneous or stimulated Ca2+ oscillations, lowered the capacity of intracellular Ca2+ stores and impaired FSH/LH-stimulated transcriptome changes for estrogen production in mouse and/or human granulosa cells. Together, these results have revealed a previously undefined role of ENaC in modulating gonadotrophin signaling in granulosa cells for estrogen homeostasis and thus female fertility.

Genome-wide variation study and inter-tissue communication analysis unveil regulatory mechanisms of egg-laying performance in chickens.

Egg-laying performance is of great economic importance in poultry, but the underlying genetic mechanisms are still elusive. In this work, we conduct a multi-omics and multi-tissue integrative study in hens with distinct egg production, to detect the hub candidate genes and construct hub molecular networks contributing to egg-laying phenotypic differences. We identifiy three hub candidate genes as egg-laying facilitators: TFPI2, which promotes the GnRH secretion in hypothalamic neuron cells; CAMK2D, which promotes the FSHß and LHß secretion in pituitary cells; and OSTN, which promotes granulosa cell proliferation and the synthesis of sex steroid hormones. We reveal key endocrine factors involving egg production by inter-tissue crosstalk analysis, and demonstrate that both a hepatokine, APOA4, and an adipokine, ANGPTL2, could increase egg production by inter-tissue communication with hypothalamic-pituitary-ovarian axis. Together, These results reveal the molecular mechanisms of multi-tissue coordinative regulation of chicken egg-laying performance and provide key insights to avian reproductive regulation.

Effect of berberine combined with metformin on autophagy in polycystic ovary syndrome by regulating AMPK/AKT/mTOR pathway.

The pathologic mechanism of polycystic ovary syndrome (PCOS) is related to increased autophagy of granulosa cells. Both berberine and metformin have been shown to improve PCOS, but whether the combination of berberine and metformin can better improve PCOS by inhibiting autophagy remains unclear. PCOS models were constructed by injecting dehydroepiandrosterone into rats, and berberine, metformin or berberine combined with metformin was administered to rats after modeling. Rats' body weight and ovarian weight were measured before and after modeling. Histopathological examination of ovarian tissue and estrous cycle analysis of rats were performed. Insulin resistance, hormone levels, oxidative stress, and lipid metabolism in PCOS rats were assessed. Expression of the AMPK/AKT/mTOR pathway and autophagy-related proteins was analyzed by Western blot assays. Granulosa cells were isolated from rat ovarian tissue and identified by immunofluorescence staining followed by transmission electron microscopy analysis. Berberine combined with metformin reduced the body weight and ovarian weight of PCOS rats, increased the number of primordial and primary follicles, decreased the number of secondary and atretic follicles, normalized the estrous cycle, and improved insulin resistance, androgen biosynthesis, oxidative stress and lipid metabolism disorders, and increased estrogen production. In addition, berberine combined with metformin reduced the number of autophagosomes in granulosa cells, which may be related to AMPK/AKT/mTOR pathway activation, decreased Beclin1 and LC3II/LC3I levels, and increased p62 expression. Berberine combined with metformin could inhibit autophagy by activating the AMPK/AKT/mTOR pathway in PCOS, indicating that berberine combined with metformin is a potential treatment strategy for PCOS.

Liraglutide improves follicle development in polycystic ovary syndrome by inhibiting CXCL10 secretion.

BACKGROUND: At present, a number of clinical trials have been carried out on GLP-1 receptor agonist liraglutide in the treatment of polycystic ovary syndrome (PCOS). However, the effect of liraglutide on follicle development and its specific mechanism are still unclear. METHODS: RNA sequencing was used to explore the molecular characteristics of granulosa cells from patients with PCOS treated with liraglutide. The levels of C-X-C motif chemokine ligand 10 (CXCL10) in follicular fluid were detected by ELISA, the expression levels of ovulation related genes and inflammatory factor genes in follicles and granulosa cells were detected by qPCR and the protein levels of connexin 43 (Cx43), Janus Kinase 2 (JAK2) and phosphorylated JAK2 were detected by Western blot. The mouse ovarian follicles culture system in vitro was used to detect the status of follicle development and ovulation. RESULTS: In the present study, we found that liraglutide inhibited the secretion of inflammatory factors in PCOS granulosa cells, among which CXCL10 was the most significant. In addition, CXCL10 was significantly higher in granulosa cells and follicular fluid in PCOS patients than in non-PCOS patients. We applied in vitro follicle culture and other techniques to carry out the mechanism exploration which revealed that CXCL10 disrupted the homeostasis of gap junction protein alpha 1 (GJA1) between oocyte and granulosa cells before physiological ovulation, thus inhibiting follicular development and ovulation. Liraglutide inhibited CXCL10 secretion in PCOS granulosa cells by inhibiting the JAK signaling pathway and can improved dehydroepiandrosterone (DHEA)-induced follicle development disorders, which is reversed by CXCL10 supplementation. CONCLUSIONS: The present study suggests that liraglutide inhibits CXCL10 secretion in granulosa cells through JAK signaling pathway, thereby improving the homeostasis of GJA1 between oocyte and granulosa cells before physiological ovulation and ultimately improving the follicular development and ovulation of PCOS, which provides more supportive evidence for the clinical application of liraglutide in the treatment of ovulatory disorders in PCOS. TRIAL REGISTRATION: Not applicable.

Unique features of KGN granulosa-like tumour cells in the regulation of steroidogenic and antioxidant genes.

The ovarian KGN granulosa-like tumour cell line is commonly used as a model for human granulosa cells, especially since it produces steroid hormones. To explore this further, we identified genes that were differentially expressed by KGN cells compared to primary human granulosa cells using three public RNA sequence datasets. Of significance, we identified that the expression of the antioxidant gene TXNRD1 (thioredoxin reductase 1) was extremely high in KGN cells. This is ominous since cytochrome P450 enzymes leak electrons and produce reactive oxygen species during the biosynthesis of steroid hormones. Gene Ontology (GO) analysis identified steroid biosynthetic and cholesterol metabolic processes were more active in primary granulosa cells, whilst in KGN cells, DNA processing, chromosome segregation and kinetochore pathways were more prominent. Expression of cytochrome P450 cholesterol side-chain cleavage (CYP11A1) and cytochrome P450 aromatase (CYP19A1), which are important for the biosynthesis of the steroid hormones progesterone and oestrogen, plus their electron transport chain members (FDXR, FDX1, POR) were measured in cultured KGN cells. KGN cells were treated with 1 mM dibutyryl cAMP (dbcAMP) or 10 µM forskolin, with or without siRNA knockdown of TXNRD1. We also examined expression of antioxidant genes, H2O2 production by Amplex Red assay and DNA damage by γH2Ax staining. Significant increases in CYP11A1 and CYP19A1 were observed by either dbcAMP or forskolin treatments. However, no significant changes in H2O2 levels or DNA damage were found. Knockdown of expression of TXNRD1 by siRNA blocked the stimulation of expression of CYP11A1 and CYP19A1 by dbcAMP. Thus, with TXNRD1 playing such a pivotal role in steroidogenesis in the KGN cells and it being so highly overexpressed, we conclude that KGN cells might not be the most appropriate model of primary granulosa cells for studying the interplay between ovarian steroidogenesis, reactive oxygen species and antioxidants.

Paeoniflorin Promotes Ovarian Development in Mice by Activating Mitophagy and Preventing Oxidative Stress.

During the development of animal organs, various adverse stimuli or toxic environments can induce oxidative stress and delay ovarian development. Paeoniflorin (PF), the main active ingredient of the traditional Chinese herb Paeonia lactiflora Pall., has protective effects on various diseases by preventing oxidative stress. However, the mechanism by which PF attenuates oxidative damage in mouse ovaries remains unclear. We evaluated the protective effects of PF on ovaries in an H2O2-induced mouse oxidative stress model. The H2O2-induced mouse ovarian oxidative stress model was used to explore the protective effect of PF on ovarian development. Histology and follicular development were observed. We then detected related indicators of cell apoptosis, oxidative stress, and autophagy in mouse ovaries. We found that PF inhibited H2O2-induced ovarian cell apoptosis and ferroptosis and promoted granulosa cell proliferation. PF prevented oxidative stress by increasing nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) expression levels. In addition, the autophagic flux of ovarian cells was activated and was accompanied by increased lysosomal biogenesis. Moreover, PF-mediated autophagy was involved in clearing mitochondria damaged by H2O2. Importantly, PF administration significantly increased the number of primordial follicles, primary follicles, secondary follicles, and antral follicles. PF administration improved ovarian sizes compared with the H2O2 group. The present study suggested that PF administration reversed H2O2-induced ovarian developmental delay and promoted follicle development. PF-activated mitophagy is crucial for preventing oxidative stress and improving mitochondrial quality.

Identification of potential diagnostic genes for atherosclerosis in women with polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS), which is the most prevalent endocrine disorder among women in their reproductive years, is linked to a higher occurrence and severity of atherosclerosis (AS). Nevertheless, the precise manner in which PCOS impacts the cardiovascular well-being of women remains ambiguous. The Gene Expression Omnibus database provided four PCOS datasets and two AS datasets for this study. Through the examination of genes originating from differentially expressed (DEGs) and critical modules utilizing functional enrichment analyses, weighted gene co-expression network (WGCNA), and machine learning algorithm, the research attempted to discover potential diagnostic genes. Additionally, the study investigated immune infiltration and conducted gene set enrichment analysis (GSEA) to examine the potential mechanism of the simultaneous occurrence of PCOS and AS. Two verification datasets and cell experiments were performed to assess biomarkers' reliability. The PCOS group identified 53 genes and AS group identified 175 genes by intersecting DEGs and key modules of WGCNA. Then, 18 genes from two groups were analyzed by machine learning algorithm. Death Associated Protein Kinase 1 (DAPK1) was recognized as an essential gene. Immune infiltration and single-gene GSEA results suggest that DAPK1 is associated with T cell-mediated immune responses. The mRNA expression of DAPK1 was upregulated in ox-LDL stimulated RAW264.7 cells and in granulosa cells. Our research discovered the close association between AS and PCOS, and identified DAPK1 as a crucial diagnostic biomarker for AS in PCOS.

Polystyrene nanoplastics induce apoptosis, autophagy, and steroidogenesis disruption in granulosa cells to reduce oocyte quality and fertility by inhibiting the PI3K/AKT pathway in female mice.

BACKGROUND: Nanoplastics (NPs) are emerging pollutants that pose risks to living organisms. Recent findings have unveiled the reproductive harm caused by polystyrene nanoparticles (PS-NPs) in female animals, yet the intricate mechanism remains incompletely understood. Under this research, we investigated whether sustained exposure to PS-NPs at certain concentrations in vivo can enter oocytes through the zona pellucida or through other routes that affect female reproduction. RESULTS: We show that PS-NPs disrupted ovarian functions and decreased oocyte quality, which may be a contributing factor to lower female fertility in mice. RNA sequencing of mouse ovaries illustrated that the PI3K-AKT signaling pathway emerged as the predominant environmental information processing pathway responding to PS-NPs. Western blotting results of ovaries in vivo and cells in vitro showed that PS-NPs deactivated PI3K-AKT signaling pathway by down-regulating the expression of PI3K and reducing AKT phosphorylation at the protein level, PI3K-AKT signaling pathway which was accompanied by the activation of autophagy and apoptosis and the disruption of steroidogenesis in granulosa cells. Since PS-NPs penetrate granulosa cells but not oocytes, we examined whether PS-NPs indirectly affect oocyte quality through granulosa cells using a granulosa cell-oocyte coculture system. Preincubation of granulosa cells with PS-NPs causes granulosa cell dysfunction, resulting in a decrease in the quality of the cocultured oocytes that can be reversed by the addition of 17ß-estradiol. CONCLUSIONS: This study provides findings on how PS-NPs impact ovarian function and include transcriptome sequencing analysis of ovarian tissue. The study demonstrates that PS-NPs impair oocyte quality by altering the functioning of ovarian granulosa cells. Therefore, it is necessary to focus on the research on the effects of PS-NPs on female reproduction and the related methods that may mitigate their toxicity.

Telomerase activity, telomere length, and the euploidy rate of human embryos.

BACKGROUND: Telomeres maintain chromosome stability, while telomerase counteracts their progressive shortening. Telomere length varies between cell types, with leukocyte telomere length (LTL) decreasing with age. Reduced telomerase activity has been linked to reproductive issues in females, such as low pregnancy rates and premature ovarian failure, with recent studies indicating correlations between telomere length in granulosa cells and IVF outcomes. OBJECTIVES: The study aims to explore the relationship between telomere length, telomerase activity, and euploid blastocyst rate in infertile women undergoing IVF/ICSI PGT-A cycles. METHODS: This prospective study involves 108 patients undergoing controlled ovarian stimulation and PGT-A. Telomere length and telomerase activity were measured in peripheral mononuclear cells and granulosa cells (GC), respectively. RESULTS: The telomere repeat copy number to single gene copy number ratio (T/S) results respectively 0.6 ± 0.8 in leukocytes and 0.7 ± 0.9 in GC. An inverse relationship was found between LTL and the patient's age (p < .01). A higher aneuploid rate was noticed in patients with short LTL, with no differences in ovarian reserve markers (p = .15), number of oocytes retrieved (p = .33), and number of MII (p = 0.42). No significant association was noticed between telomere length in GC and patients' age (p = 0.95), in ovarian reserve markers (p = 0.32), number of oocytes retrieved (p = .58), number of MII (p = .74) and aneuploidy rate (p = .65). CONCLUSION: LTL shows a significant inverse correlation with patient age and higher aneuploidy rates. Telomere length in GCs does not correlate with patient age or reproductive outcomes, indicating differential telomere dynamics between leukocytes and granulosa cells.

The role of vitamin D3 in follicle development.

Vitamin D3 plays a crucial role in female reproduction. As research progresses, the mechanisms of action of vitamin D3 on follicular development have been widely discussed. Firstly, key enzymes involved in the synthesis and metabolism of vitamin D3 have been discovered in the ovary, suggesting that vitamin D3 can be synthesized and metabolized locally within the ovary. Additionally, the detection of vitamin D3 receptors (VDR) in follicles suggests that vitamin D3 may exert its effects by binding specifically to these receptors during follicular development. Further research indicates that vitamin D3 promotes follicular growth by enhancing the development of granulosa cells (GCs) and oocytes. Currently, the mechanism of action of vitamin D3 in follicular development is becoming increasingly clear. Vitamin D3 promotes oocyte development by regulating molecules involved in meiotic arrest in oocytes. It also enhances granulosa cell proliferation by stimulating steroid hormone synthesis and cell cycle regulation. Additionally, vitamin D3 exerts anti-inflammatory effects by reducing oxidative stress and advanced glycation end-products (AGEs), mitigating the detrimental effects of inflammation on follicular development. These functions of vitamin D3 have clinical applications, such as in treating polycystic ovary syndrome (PCOS), improving female fertility, and enhancing outcomes in in vitro fertilization (IVF). This review summarizes the research progress on the role and mechanisms of vitamin D3 in follicular development and briefly summarizes its clinical applications.

Single-cell transcriptomic profiling unveils insights into ovarian fibrosis in obese mice.

BACKGROUND: Adiposity profoundly impacts reproductive health in both humans and animals. However, the precise subpopulations contributing to infertility under obese conditions remain elusive. RESULTS: In this study, we established an obese mouse model through an eighteen-week high-fat diet regimen in adult female mice. Employing single-cell RNA sequencing (scRNA-seq), we constructed a comprehensive single-cell atlas of ovarian tissues from these mice to scrutinize the impact of obesity on the ovarian microenvironment. ScRNA-seq revealed notable alterations in the microenvironment of ovarian tissues in obese mice. Granulosa cells, stromal cells, T cells, and macrophages exhibited functional imbalances compared to the control group. We observed heightened interaction strength in the SPP1-CD44 pairing within lgfbp7+ granulosa cell subtypes and Il1bhigh monocyte subtypes in the ovarian tissues of obese mice. Moreover, the interaction strength between Il1bhigh monocyte subtypes and Pdgfrb+ stromal cell subtypes in the form of TNF - TNFrsf1α interaction was also enhanced subsequently to obesity, potentially contributing to ovarian fibrosis pathogenesis. CONCLUSIONS: We propose a model wherein granulosa cells secrete SPP1 to activate monocytes, subsequently triggering TNF-α secretion by monocytes, thereby activating stromal cells and ultimately leading to the development of ovarian fibrosis. Intervening in this process may represent a promising avenue for improving clinical outcomes in fertility treatments for obese women.

Transcriptome Dynamics and Cell Dialogs Between Oocytes and Granulosa Cells in Mouse Follicle Development.

The development and maturation of follicles is a sophisticated and multistage process. The dynamic gene expression of oocytes and their surrounding somatic cells and the dialogs between these cells are critical to this process. In this study, we accurately classified the oocyte and follicle development into nine stages and profiled the gene expression of mouse oocytes and their surrounding granulosa cells and cumulus cells. The clustering of the transcriptomes showed the trajectories of two distinct development courses of oocytes and their surrounding somatic cells. Gene expression changes precipitously increased at Type 4 stage and drastically dropped afterward within both oocytes and granulosa cells. Moreover, the number of differentially expressed genes between oocytes and granulosa cells dramatically increased at Type 4 stage, most of which persistently passed on to the later stages. Strikingly, cell communications within and between oocytes and granulosa cells became active from Type 4 stage onward. Cell dialogs connected oocytes and granulosa cells in both unidirectional and bidirectional manners. TGFB2/3, TGFBR2/3, INHBA/B, and ACVR1/1B/2B of TGF-ß signaling pathway functioned in the follicle development. NOTCH signaling pathway regulated the development of granulosa cells. Additionally, many maternally DNA methylation- or H3K27me3-imprinted genes remained active in granulosa cells but silent in oocytes during oogenesis. Collectively, Type 4 stage is the key turning point when significant transcription changes diverge the fate of oocytes and granulosa cells, and the cell dialogs become active to assure follicle development. These findings shed new insights on the transcriptome dynamics and cell dialogs facilitating the development and maturation of oocytes and follicles.

The Functions and Application Prospects of Hepatocyte Growth Factor in Reproduction.

Hepatocyte growth factor (HGF) is expressed in multiple systems and mediates a variety of biological activities, such as mitosis, motility, and morphogenesis. A growing number of studies have revealed the expression patterns and functions of HGF in ovarian and testicular physiology from the prenatal to the adult stage. HGF regulates folliculogenesis and steroidogenesis by modulating the functions of theca cells and granulosa cells in the ovary. It also mediates somatic cell proliferation and steroidogenesis, thereby affecting spermatogenesis in males. In addition to its physiological effects on the reproductive system, HGF has shown advantages in preclinical studies over recent years for the treatment of male and female infertility, particularly in women with premature ovarian insufficiency. This review aims to summarize the pleiotropic functions of HGF in the reproductive system and to provide prospects for its clinical application.

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.

Peroxiredoxin 4 deficiency induces accelerated ovarian aging through destroyed proteostasis in granulosa cells.

Ovarian aging, a complex and challenging concern within the realm of reproductive medicine, is associated with reduced fertility, menopausal symptoms and long-term health risks. Our previous investigation revealed a correlation between Peroxiredoxin 4 (PRDX4) and human ovarian aging. The purpose of this research was to substantiate the protective role of PRDX4 against ovarian aging and elucidate the underlying molecular mechanism in mice. In this study, a Prdx4-/- mouse model was established and it was observed that the deficiency of PRDX4 led to only an accelerated decline of ovarian function in comparison to wild-type (WT) mice. The impaired ovarian function observed in this study can be attributed to an imbalance in protein homeostasis, an exacerbation of endoplasmic reticulum stress (ER stress), and ultimately an increase in apoptosis of granulosa cells. Furthermore, our research reveals a noteworthy decline in the expression of Follicle-stimulating hormone receptor (FSHR) in aging Prdx4-/- mice, especially the functional trimer, due to impaired disulfide bond formation. Contrarily, the overexpression of PRDX4 facilitated the maintenance of protein homeostasis, mitigated ER stress, and consequently elevated E2 levels in a simulated KGN cell aging model. Additionally, the overexpression of PRDX4 restored the expression of the correct spatial conformation of FSHR, the functional trimer. In summary, our research reveals the significant contribution of PRDX4 in delaying ovarian aging, presenting a novel and promising therapeutic target for ovarian aging from the perspective of endoplasmic reticulum protein homeostasis.