SMAD4 promotes somatic-germline contact during murine oocyte growth.

Development of the mammalian oocyte requires physical contact with the surrounding granulosa cells of the follicle, which provide it with essential nutrients and regulatory signals. This contact is achieved through specialized filopodia, termed transzonal projections (TZPs), that extend from the granulosa cells to the oocyte surface. Transforming growth factor (TGFß) family ligands produced by the oocyte increase the number of TZPs, but how they do so is unknown. Using an inducible Cre recombinase strategy together with expression of green fluorescent protein to verify Cre activity in individual cells, we examined the effect of depleting the canonical TGFß mediator, SMAD4, in mouse granulosa cells. We observed a 20-50% decrease in the total number of TZPs in SMAD4-depleted granulosa cell-oocyte complexes, and a 50% decrease in the number of newly generated TZPs when the granulosa cells were reaggregated with wild-type oocytes. Three-dimensional image analysis revealed that TZPs of SMAD4-depleted cells were longer than controls and more frequently oriented towards the oocyte. Strikingly, the transmembrane proteins, N-cadherin and Notch2, were reduced by 50% in SMAD4-depleted cells. SMAD4 may thus modulate a network of cell adhesion proteins that stabilize the attachment of TZPs to the oocyte, thereby amplifying signalling between the two cell types.

Interlukin-22 improves ovarian function in polycystic ovary syndrome independent of metabolic regulation: a mouse-based experimental study.

BACKGROUND: Polycystic ovary syndrome (PCOS) is a reproductive endocrine disorder with multiple metabolic abnormalities. Most PCOS patients have concomitant metabolic syndromes such as insulin resistance and obesity, which often lead to the development of type II diabetes and cardiovascular disease with serious consequences. Current treatment of PCOS with symptomatic treatments such as hormone replacement, which has many side effects. Research on its origin and pathogenesis is urgently needed. Although improving the metabolic status of the body can alleviate reproductive function in some patients, there is still a subset of patients with metabolically normal PCOS that lacks therapeutic tools to address ovarian etiology. METHODS: The effect of IL-22 on PCOS ovarian function was verified in a non-metabolic PCOS mouse model induced by dehydroepiandrosterone (DHEA) and rosiglitazone, as well as granulosa cell -specific STAT3 knockout (Fshrcre+Stat3f/f) mice (10 groups totally and n = 5 per group). Mice were maintained under controlled temperature and lighting conditions with free access to food and water in a specific pathogen-free (SPF) facility. Secondary follicles separated from Fshrcre+Stat3f/f mice were cultured in vitro with DHEA to mimic the hyperandrogenic environment in PCOS ovaries (4 groups and n = 7 per group) and then were treated with IL-22 to investigate the specific role of IL-22 on ovarian function. RESULTS: We developed a non-metabolic mice model with rosiglitazone superimposed on DHEA. This model has normal metabolic function as evidenced by normal glucose tolerance without insulin resistance and PCOS-like ovarian function as evidenced by irregular estrous cycle, polycystic ovarian morphology (PCOM), abnormalities in sex hormone level. Supplementation with IL-22 improved these ovarian functions in non-metabolic PCOS mice. Application of DHEA in an in vitro follicular culture system to simulate PCOS follicular developmental block and ovulation impairment. Follicles from Fshrcre+Stat3f/f did not show improvement in POCS follicle development with the addition of IL-22. In DHEA-induced PCOS mice, selective ablation of STAT3 in granulosa cells significantly reversed the ameliorative effect of IL-22 on ovarian function. CONCLUSION: IL-22 can improve non-metabolic PCOS mice ovarian function. Granulosa cells deficient in STAT3 reverses the role of IL-22 in alleviating ovary dysfunction in non-metabolic PCOS mice.

Ovarian PERK/NRF2/CX43/StAR/progesterone pathway activation mediates female reproductive dysfunction induced by cold exposure.

Ambient air temperature is a key factor affecting human health. Female reproductive disorders are representative health risk events under low temperature. However, the mechanism involving in cold-induced female reproductive disorders remains largely unknown. Female mice were intermittently exposed to cold conditions (4 °C) to address the health risk of low temperature on female reproductive system. Primary granulosa cells (GCs) were prepared and cultured under low temperature (35 °C) or exposed to ß3-adrenoreceptor agonist, isoproterenol, to mimic the condition of cold exposure. Western-blot, RT-PCR, co-IP, ELISA, pharmacological inhibition or siRNA-mediated knockdown of target gene were performed to investigate the possible role of hormones, gap conjunction proteins, and ER stress sensor protein in regulating female reproductive disorders under cold exposure. Cold exposure induced estrous cycle disorder and follicular dysplasia in female mice, accompanying with abnormal upregulation of progesterone and its synthetic rate-limiting enzyme, StAR, in the ovarian granulosa cells. Under the same conditions, an increase in connexin 43 (CX43) expressions in the GCs was also observed, which contributed to elevated progesterone levels in the ovary. Moreover, ER stress sensor protein, PERK, was activated in the ovarian GCs after cold exposure, leading to the upregulation of downstream NRF2-dependent CX43 transcription and aberrant increase in progesterone synthesis. Most importantly, blocking PERK expression in vivo significantly inhibited NRF2/CX43/StAR/progesterone pathway activation in the ovary and efficiently rescued the prolongation of estrous cycle and the increase in follicular atresia of the female mice induced by cold stress. We have elucidated the mechanism of ovarian PERK/NRF2/CX43/StAR/progesterone pathway activation in mediating female reproductive disorder under cold exposure. Targeting PERK might be helpful for maintaining female reproductive health under cold conditions.

Cholecystokinin-mediated effect of insulin pathway on the steroidogenic activity of follicular granulosa cells in Camelus bactrianus: In vitro study.

The current study aimed to explore the molecular mechanism by which the cholecystokinin (CCK)-mediated CCKAR and CCKBR, as well as the molecular mechanisms of CCK-mediated insulin signalling pathway, regulate oestrogen in the granulosa cells. Also, the expression of CCK in ovaries, uterus, hypothalamus and pituitary gland was investigated in Camelus bactrianus. Ovaries, uterus, hypothalamus and pituitary gland were collected from six, three before ovulation (control) and three after ovulation, slaughtered Camelus bactrianus. Ovulation was induced by IM injection of seminal plasma before slaughtering in the ovulated group. The results showed that there were differences in the transcription and protein levels of CCK in various tissues before and after ovulation (p < .05, p < .01). After transfection with p-IRES2-EGFP-CCK, the mRNA and protein levels of CCK, CCKAR, CCKBR and ER in follicular granulosa cells were significantly upregulated (p < .05, p < .01), and the content of E2 was significantly upregulated (p < .01); On the contrary, after transfection with si-CCK, the mRNA and protein levels of CCK, CCKAR, CCKBR and ER in follicular granulosa cells were significantly downregulated (p < .05, p < .01), and the content of E2 was significantly downregulated (p < .01). Regulating CCK can affect the mRNA levels of INS, INSR, IGF and IGF-R. In summary, regulating the expression level of CCK can activate insulin-related signalling pathways by CCKR, thereby regulating the steroidogenic activity of granulosa cells.

Ti3C2 nanosheet-induced autophagy derails ovarian functions.

BACKGROUND: Two-dimensional ultrathin Ti3C2 (MXene) nanosheets have gained significant attention in various biomedical applications. Although previous studies have described the accumulation and associated damage of Ti3C2 nanosheets in the testes and placenta. However, it is currently unclear whether Ti3C2 nanosheets can be translocated to the ovaries and cause ovarian damage, thereby impairing ovarian functions. RESULTS: We established a mouse model with different doses (1.25, 2.5, and 5 mg/kg bw/d) of Ti3C2 nanosheets injected intravenously for three days. We demonstrated that Ti3C2 nanosheets can enter the ovaries and were internalized by granulosa cells, leading to a decrease in the number of primary, secondary and antral follicles. Furthermore, the decrease in follicles is closely associated with higher levels of FSH and LH, as well as increased level of E2 and P4, and decreased level of T in mouse ovary. In further studies, we found that exposure toTi3C2 nanosheets increased the levels of Beclin1, ATG5, and the ratio of LC3II/Ι, leading to autophagy activation. Additionally, the level of P62 increased, resulting in autophagic flux blockade. Ti3C2 nanosheets can activate autophagy through the PI3K/AKT/mTOR signaling pathway, with oxidative stress playing an important role in this process. Therefore, we chose the ovarian granulosa cell line (KGN cells) for in vitro validation of the impact of autophagy on the hormone secretion capability. The inhibition of autophagy initiation by 3-Methyladenine (3-MA) promoted smooth autophagic flow, thereby partially reduced the secretion of estradiol and progesterone by KGN cells; Whereas blocking autophagic flux by Rapamycin (RAPA) further exacerbated the secretion of estradiol and progesterone in cells. CONCLUSION: Ti3C2 nanosheet-induced increased secretion of hormones in the ovary is mediated through the activation of autophagy and impairment of autophagic flux, which disrupts normal follicular development. These results imply that autophagy dysfunction may be one of the underlying mechanisms of Ti3C2-induced damage to ovarian granulosa cells. Our findings further reveal the mechanism of female reproductive toxicity induced by Ti3C2 nanosheets.

Synergistic cooperation between the ß-catenin and SF1 regulates progesterone synthesis in laying hen ovarian granulosa cells.

The development of ovarian follicles in poultry is a key factor affecting the performance of egg production. Ovarian follicle development is regulated via the Wnt/ß-catenin signaling pathway, and ß-catenin, encoded by CTNNB1, is a core component of this pathway. In this study, using ovary GCs from laying hens, we investigated the regulatory role of CTNNB1 in steroid synthesis. We found that CTNNB1 significantly regulates the expression of StAR and CYP11A1 (key genes related to progesterone synthesis) and the secretion of progesterone (P4). Furthermore, simultaneous overexpression of CTNNB1 and SF1 resulted in significantly higher levels of CYP11A1 and secretion of P4 than in cells overexpressing CTNNB1 or SF1 alone. We also found that in GCs overexpressing SF1, levels of CYP11A1 and secreted P4 were significantly greater than in controls. Silencing of CYP11A1 resulted in the inhibition of P4 secretion while overexpression of SF1 in CYP11A1-silenced cells restored P4 secretion to normal levels. Together, these results indicate that synergistic cooperation between the ß-catenin and SF1 regulates progesterone synthesis in laying hen ovarian hierarchical granulosa cells to promote CYP11A1 expression.

Hyperandrogenic environment regulates the function of ovarian granulosa cells by modulating macrophage polarization in PCOS.

BACKGROUND: Polycystic ovary syndrome (PCOS) is a common endocrine-metabolic disorder characterized by oligo-anovulation, hyperandrogenism, and polycystic ovaries, with hyperandrogenism being the most prominent feature of PCOS patients. However, whether excessive androgens also exist in the ovarian microenvironment of patients with PCOS, and their modulatory role on ovarian immune homeostasis and ovarian function, is not clear. METHODS: Follicular fluid samples from patients participating in their first in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatment were collected. Androgen concentration of follicular fluid was assayed by chemiluminescence, and the macrophage M1:M2 ratio was detected by flow cytometry. In an in vitro model, we examined the regulatory effects of different concentrations of androgen on macrophage differentiation and glucose metabolism levels using qRT-PCR, Simple Western and multi-factor flow cytometry assay. In a co-culture model, we assessed the effect of a hyperandrogenic environment in the presence or absence of macrophages on the function of granulosa cells using qRT-PCR, Simple Western, EdU assay, cell cycle assay, and multi-factor flow cytometry assay. RESULTS: The results showed that a significantly higher androgen level and M1:M2 ratio in the follicular fluid of PCOS patients with hyperandrogenism. The hyperandrogenic environment promoted the expression of pro-inflammatory and glycolysis-related molecules and inhibited the expression of anti-inflammatory and oxidative phosphorylation-related molecules in macrophages. In the presence of macrophages, a hyperandrogenic environment significantly downregulated the function of granulosa cells. CONCLUSION: There is a hyperandrogenic microenvironment in the ovary of PCOS patients with hyperandrogenism. Hyperandrogenic microenvironment can promote the activation of ovarian macrophages to M1, which may be associated with the reprogramming of macrophage glucose metabolism. The increased secretion of pro-inflammatory cytokines by macrophages in the hyperandrogenic microenvironment would impair the normal function of granulosa cells and interfere with normal ovarian follicle growth and development.

Ghrelin Alleviates Inflammation, Insulin Resistance, and Reproductive Abnormalities in Mice with Polycystic Ovary Syndrome via the TLR4-NF-κB Signaling Pathway.

BACKGROUND: Polycystic ovary syndrome (PCOS) commonly impacts fertile females with potentially severe effects on fertility and metabolism. Blood ghrelin levels are lower in PCOS patients, and exogenous supplements have been proposed for their potential to trigger anti-inflammatory effects at the cellular level. This study aimed to investigate whether pretreatment with ghrelin reduced inflammation, insulin resistance, and reproductive abnormalities in PCOS and the underlying mechanism of this disorder. METHODS: Ghrelin supplementation was first tested in an inflammation model using human ovarian granulosa cells (KGN cells) that were built by treated with Lipolyaccharide. KGN cells were pretreated with ghrelin and exposed to lipopolysaccharide (LPS). Inflammatory gene expression and cytokine production were analyzed by Enzyme-linked immunosorbent assay (ELISA). Based on these results, the PCOS mice model was built with Dehydroepiandrosterone (DHEA) and a high-fat diet. The mRNA and protein expressions of inflammatory factors including Toll-like receptor 4 (TLR4), nuclear factor kappa-B-p65 (NF-κB-p65), Phospho-NF-κB-p65 (p-NF-κB-p65) and myeloid differentiation factor 88 (MYD88) related to the TLR4/NF-κB signaling pathway were evaluated in KGN cells and mouse ovarian tissues using Real-Time Quantitative Polymerase Chain Reaction (RT-qPCR) and western blot, respectively. Lipid metabolism was quantified via an automated biochemical analyzer. RESULTS: The mRNA and protein expressions of interleukin-6 (IL-6), interleukin-1 beta (IL-1ß), and tumor necrosis factor alpha (TNF-α) in ghrelin pretreated KGN cells were lower than the LPS group (p < 0.05). Protein expression was reduced for TLR4, NF-κB-p65, and MYD88 within KGN cells of ghrelin groups compared to the LPS group (p < 0.05). Ghrelin treatment restored the estrous cycle and slowed weight gain and abdominal fat weight of PCOS mice (p < 0.05). Ghrelin treatment decreased the serum concentrations of testosterone, luteinizing hormone, insulin, IL-6, IL-1ß, and TNF-α compared to the PCOS group (p < 0.05). Estradiol concentrations of mice treated with ghrelin were higher than the PCOS group (p < 0.05). The concentrations of low and high-density lipoprotein, triglyceride, and cholesterol in mice treated with ghrelin were lower than in the PCOS mice (p < 0.05). Inflammatory gene expression for IL-6, IL-1ß, TNF-α, TLR4, NF-κB-p65, and MYD88 decreased in the ovarian tissues of ghrelin-treated mice compared to the PCOS group (p < 0.05), along with reduced protein expression of TLR4, p-NF-κB-p65, and MYD88 (p < 0.05). CONCLUSIONS: In the present study, ghrelin treatment effectively reduced inflammation in vitro, and attenuated insulin resistance and reproductive abnormalities in PCOS mice through the TLR4/NF-κB signaling pathway, highlighting potential therapeutic avenues for future PCOS treatments and research directions.

Mechanism of Apoptosis in Porcine Ovarian Granulosa Cells Triggered by T-2 Toxin.

T-2 toxin (T-2), an A-type mono mycotoxin produced by various Fusarium species, disrupts DNA/RNA and protein synthesis upon entering the body, resulting in pathological conditions in various tissues/organs and posing a significant threat to human and animal health. However, the mechanisms underlying its toxicity remain unclear. With the goal of learning how T-2 affects reproduction in animals, we utilized primary porcine ovarian granulosa cells (pGCs) as a carrier in vitro and constructed concentration models for analyzing cell morphology and RNA-sequencing (RNA-seq). Our findings showed that T-2 could influence pGCs morphology, induce cell cycle arrest, and promote apoptosis in a dose-dependent manner. The results of RNA-seq analyses indicated that a total of 8216 genes exhibited significant differential expression (DEG) following T-2 treatment, of which 4812 were observed to be down-regulated and 3404 were up-regulated. The DEGs following T-2 toxin treatment of pGCs had a notable impact on many metabolic pathways such as PI3K-Akt, Ras, MAPK, and apoptosis, which in turn altered important physiological processes. Gene set enrichment analysis (GSEA) indicated that the differences in the harmful effects of T-2 might be caused by the varying control of cellular processes and the pathway responsible for steroid metabolism. These results present further insights regarding the mechanism of T-2 action on sow reproductive toxicity, enhance our understanding of T-2 reproductive toxicological effects, and lay a theoretical foundation for the judicious prevention of T-2-induced reproductive toxicity.

Normal Ovarian Function in Subfertile Mouse with Amhr2-Cre-Driven Ablation of Insr and Igf1r.

Insulin receptor signaling promotes cell differentiation, proliferation, and growth which are essential for oocyte maturation, embryo implantation, endometrial decidualization, and placentation. The dysregulation of insulin signaling in women with metabolic syndromes including diabetes exhibits poor pregnancy outcomes that are poorly understood. We utilized the Cre/LoxP system to target the tissue-specific conditional ablation of insulin receptor (Insr) and insulin-like growth factor-1 receptor (Igf1r) using an anti-Mullerian hormone receptor 2 (Amhr2) Cre-driver which is active in ovarian granulosa and uterine stromal cells. Our long-term goal is to examine insulin-dependent molecular mechanisms that underlie diabetic pregnancy complications, and our conditional knockout models allow for such investigation without confounding effects of ligand identity, source and cross-reactivity, or global metabolic status within dams. Puberty occurred with normal timing in all conditional knockout models. Estrous cycles progressed normally in Insrd/d females but were briefly stalled in diestrus in Igf1rd/d and double receptor (DKO) mice. The expression of vital ovulatory genes (Lhcgr, Pgr, Ptgs2) was not significantly different in 12 h post-hCG superovulated ovaries in knockout mice. Antral follicles exhibited an elevated apoptosis of granulosa cells in Igf1rd/d and DKO mice. However, the distribution of ovarian follicle subtypes and subsequent ovulations was normal in all insulin receptor mutants compared to littermate controls. While ovulation was normal, all knockout lines were subfertile suggesting that the loss of insulin receptor signaling in the uterine stroma elicits implantation and decidualization defects responsible for subfertility in Amhr2-Cre-derived insulin receptor mutants.

Regulation and Role of Adiponectin Secretion in Rat Ovarian Granulosa Cells.

Adiponectin is an important adipokine involved in glucose and lipid metabolism, but its secretion and potential role in regulating glucose utilization during ovarian development remains unclear. This study aims to investigate the mechanism and effects of follicle-stimulating hormones (FSHs) on adiponectin secretion and its following impact on glucose transport in the granulosa cells of rat ovaries. A range of experimental techniques were utilized to test our research, including immunoblotting, immunohistochemistry, immunofluorescence, ELISA, histological staining, real-time quantitative PCR, and transcriptome analysis. The immunohistochemistry results indicated that adiponectin was primarily located in the granulosa cells of rat ovaries. In primary granulosa cells cultured in vitro, both Western blot and immunofluorescence assays demonstrated that FSH significantly induced adiponectin secretion within 2 h of incubation, primarily via the PKA signaling pathway rather than the PI3K/AKT pathway. Concurrently, the addition of the AdipoR1/AdipoR2 dual agonist AdipoRon to the culture medium significantly stimulated the protein expression of GLUT1 in rat granulosa cells, resulting in enhanced glucose absorption. Consistent with these in vitro findings, rats injected with eCG (which shares structural and functional similarities with FSH) exhibited significantly increased adiponectin levels in both the ovaries and blood. Moreover, there was a notable elevation in mRNA and protein levels of AdipoRs and GLUTs following eCG administration. Transcriptomic analysis further revealed a positive correlation between the expression of the intraovarian adiponectin system and glucose transporter. The present study represents a novel investigation, demonstrating that FSH stimulates adiponectin secretion in ovarian granulosa cells through the PKA signaling pathway. This mechanism potentially influences glucose transport (GLUT1) and utilization within the ovaries.

ADPN Regulates Oxidative Stress-Induced Follicular Atresia in Geese by Modulating Granulosa Cell Apoptosis and Autophagy.

Geese are susceptible to oxidative stress during reproduction, which can lead to follicular atresia and impact egg production. Follicular atresia is directly triggered by the apoptosis and autophagy of granulosa cells (GCs). Adiponectin (ADPN), which is secreted by adipose tissue, has good antioxidant and anti-apoptotic capacity, but its role in regulating the apoptosis of GCs in geese is unclear. To investigate this, this study examined the levels of oxidative stress, apoptosis, and autophagy in follicular tissues and GCs using RT-qPCR, Western blotting, immunofluorescence, flow cytometry, transcriptomics and other methods. Atretic follicles exhibited high levels of oxidative stress and apoptosis, and autophagic flux was obstructed. Stimulating GCs with H2O2 produced results similar to those of atretic follicles. The effects of ADPN overexpression and knockdown on oxidative stress, apoptosis and autophagy in GCs were investigated. ADPN was found to modulate autophagy and reduced oxidative stress and apoptosis in GCs, in addition to protecting them from H2O2-induced damage. These results may provide a reasonable reference for improving egg-laying performance of geese.

The Presence of TGFß3 in Human Ovarian Intrafollicular Fluid and Its Involvement in Thromboxane Generation in Follicular Granulosa Cells through a Canonical TGFßRI, Smad2/3 Signaling Pathway and COX-2 Induction.

Ovarian follicular fluid (FF) has a direct impact on oocyte quality, playing key roles in fertilization, implantation, and early embryo development. In our recent study, we found FF thromboxane (TX) to be a novel factor inversely correlated with oocyte maturation and identified thrombin, transforming growth factor ß (TGFß), TNF-α, and follicular granulosa cells (GCs) as possible contributors to FF TX production. Therefore, this study sought to investigate the role of TGFß3 in regulating TX generation in human ovarian follicular GCs. TGFß3 was differentially and significantly present in the FF of large and small follicles obtained from IVF patients with average concentrations of 68.58 ± 12.38 and 112.55 ± 14.82 pg/mL, respectively, and its levels were correlated with oocyte maturity. In an in vitro study, TGFß3 induced TX generation/secretion and the converting enzyme-COX-2 protein/mRNA expression both in human HO23 and primary cultured ovarian follicular GCs. While TGFßRI and Smad2/3 signaling was mainly required for COX-2 induction, ERK1/2 appeared to regulate TX secretion. The participation of Smad2/3 and COX-2 in TGFß3-induced TX generation/secretion could be further supported by the observations that Smad2/3 phosphorylation and nuclear translocation and siRNA knockdown of COX-2 expression compromised TX secretion in GCs challenged with TGFß3. Taken together, the results presented here first demonstrated that FF TGFß3 levels differ significantly in IVF patients' large preovulatory and small mid-antral follicles and are positively associated with oocyte maturation. TGFß3 can provoke TX generation by induction of COX-2 mRNA/protein via a TGFßR-related canonical Smad2/3 signaling pathway, and TX secretion possibly by ERK1/2. These imply that TGFß3 is one of the inducers for yielding FF TX in vivo, which may play a role in folliculogenesis and oocyte maturation.

Luteolin and its analog luteolin-7-methylether from Leonurus japonicus Houtt suppress aromatase-mediated estrogen biosynthesis to alleviate polycystic ovary syndrome by the inhibition of tumor progression locus 2.

ETHNOPHARMACOLOGICAL RELEVANCE: Leonurus japonicus Houtt (L. japonicus, Chinese motherwort), known as Yi Mu Cao which means "good for women", has long been widely used in China and other Asian countries to alleviate gynecological disorders, often characterized by estrogen dysregulation. It has been used for the treatment of polycystic ovary syndrome (PCOS), a common endocrine disorder in women but the underlying mechanism remains unknown. AIM OF THE STUDY: The present study was designed to investigate the effect and mechanism of flavonoid luteolin and its analog luteolin-7-methylether contained in L. japonicus on aromatase, a rate-limiting enzyme that catalyzes the conversion of androgens to estrogens and a drug target to induce ovulation in PCOS patients. MATERIALS AND METHODS: Estrogen biosynthesis in human ovarian granulosa cells was examined using ELISA. Western blots were used to explore the signaling pathways in the regulation of aromatase expression. Transcriptomic analysis was conducted to elucidate the potential mechanisms of action of compounds. Finally, animal models were used to assess the therapeutic potential of these compounds in PCOS. RESULTS: Luteolin potently inhibited estrogen biosynthesis in human ovarian granulosa cells stimulated by follicle-stimulating hormone. This effect was achieved by decreasing cAMP response element-binding protein (CREB)-mediated expression of aromatase. Mechanistically, luteolin and luteolin-7-methylether targeted tumor progression locus 2 (TPL2) to suppress mitogen-activated protein kinase 3/6 (MKK3/6)-p38 MAPK-CREB pathway signaling. Transcriptional analysis showed that these compounds regulated the expression of different genes, with the MAPK signaling pathway being the most significantly affected. Furthermore, luteolin and luteolin-7-methylether effectively alleviated the symptoms of PCOS in mice. CONCLUSIONS: This study demonstrates a previously unrecognized role of TPL2 in estrogen biosynthesis and suggests that luteolin and luteolin-7-methylether have potential as novel therapeutic agents for the treatment of PCOS. The results provide a foundation for further development of these compounds as effective and safe therapies for women with PCOS.

Cyclophosphamide induces ovarian granulosa cell ferroptosis via a mechanism associated with HO-1 and ROS-mediated mitochondrial dysfunction.

Abnormal granulosa cell (GC) death contributes to cyclophosphamide (CTX) induced primary ovarian insufficiency (POI). To investigate the contribution of GCs to POI, gene profiles of GCs exposed to CTX were assessed using RNA-Seq and bioinformatics analysis. The results showed the differentially expressed genes (DEGs) were enriched in the ferroptosis-related pathway, which is correlated with upregulated heme oxygenase 1 (HO-1) and downregulated glutathione peroxidase-4 (GPX4). Using CTX-induced cell culture (COV434 and KGN cells), the levels of iron, reactive oxygen species (ROS), lipid peroxide, mitochondrial superoxide, mitochondrial morphology and mitochondrial membrane potential (MMP) were detected by DCFDA, MitoSOX, C11-BODIPY, MitoTracker, Nonylacridine Orange (NAO), JC-1 and transmission electron microscopy respectively. The results showed iron overload and disrupted ROS, including cytoROS, mtROS and lipROS homeostasis, were associated with upregulation of HO-1 and could induce ferroptosis via mitochondrial dysfunction in CTX-induced GCs. Moreover, HO-1 inhibition could suppress ferroptosis induced GPX4 depletion. This implies a role for ROS in CTX-induced ferroptosis and highlights the effect of HO-1 modulators in improving CTX-induced ovarian damage, which may provide a theoretical basis for preventing or restoring GC and ovarian function in patients with POI.

Wine- and stir-frying processing of Cuscutae Semen enhance its ability to alleviate oxidative stress and apoptosis via the Keap 1-Nrf2/HO-1 and PI3K/AKT pathways in H2O2-challenged KGN human granulosa cell line.

BACKGROUND: Cuscutae Semen (CS) has been prescribed in traditional Chinese medicine (TCM) for millennia as an aging inhibitor, an anti-inflammatory agent, a pain reliever, and an aphrodisiac. Its three main forms include crude Cuscutae Semen (CCS), wine-processed CS (WCS), and stir-frying-processed CS (SFCS). Premature ovarian insufficiency (POI) is a globally occurring medical condition. The present work sought a highly efficacious multi-target therapeutic approach against POI with minimal side effects. Finally, it analyzed the relative differences among CCS, WCS and SFCS in terms of their therapeutic efficacy and modes of action against H2O2-challenged KGN human granulosa cell line. METHODS: In this study, ultrahigh-performance liquid chromatography (UPLC)-Q-ExactiveTM Orbitrap-mass spectrometry (MS), oxidative stress indices, reactive oxygen species (ROS), Mitochondrial membrane potential (MMP), real-time PCR, Western blotting, and molecular docking were used to investigate the protective effect of CCS, WCS and SFCS on KGN cells oxidative stress and apoptosis mechanisms. RESULTS: The results confirmed that pretreatment with CCS, WCS and SFCS reduced H2O2-induced oxidative damage, accompanied by declining ROS levels and malondialdehyde (MDA) accumulation in the KGN cells. CCS, WCS and SFCS upregulated the expression of antioxidative levels (GSH, GSH/GSSG ratio, SOD, T-AOC),mitochondrial membrane potential (MMP) and the relative mRNA(Nrf2, Keap1, NQO-1, HO-1, SOD-1, CAT). They inhibited apoptosis by upregulating Bcl-2, downregulating Bax, cleaved caspase-9, and cleaved caspase-3, and lowering the Bax/Bcl-2 ratio. They also exerted antioxidant efficacy by partially activating the PI3K/Akt and Keap1-Nrf2/HO-1 signaling pathways. CONCLUSIONS: The results of the present work demonstrated the inhibitory efficacy of CCS, WCS and SFCS against H2O2-induced oxidative stress and apoptosis in KGN cells and showed that the associated mechanisms included Keap1-Nrf2/HO-1 activation, P-PI3K upregulation, and P-Akt-mediated PI3K-Akt pathway induction.

Melatonin regulates the antioxidant capacity of sheep granulosa cells through a novel uORF-Nrf2aa mediated Nrf2/KEAP1 pathway.

Ovarian dysfunction stands as a prevalent contributor to female infertility, with its etiology intertwined with genetic, autoimmune, and environmental factors. Within the ovarian follicles, granulosa cells (GCs) represent the predominant cell population. Alterations in GCs, notably oxidative stress (OS) and the consequential surge in reactive oxygen species (ROS), play pivotal roles in the orchestration of ovarian function. Nrf2aa, a newly identified upstream open reading frame (uORF), is situated within the 5' untranslated region (5'UTR) of sheep Nrf2 mRNA and is regulated by melatonin, a crucial intrafollicular antioxidant. In this study, we have noted that Nrf2aa has the capacity to encode a peptide and exerts a negative regulatory effect on the translation efficiency (TE) of the Nrf2 CDs region. Further in vitro experiments, we observed that interfering with Nrf2aa can enhance the cellular functionality of GCs under 3-np-induced oxidative stress, while overexpressing Nrf2aa has the opposite effect. Furthermore, overexpression of Nrf2aa counteracts the rescuing effect of melatonin on the cellular functions of GCs under oxidative stress conditions, including estrogen secretion, proliferation, apoptosis, and many more. Finally, we confirmed that Nrf2aa, by regulating the expression of key proteins in the Nrf2/KEAP1 signaling pathway, further modulates the antioxidant levels in GCs.

Bisphenol A and its structural analogues exhibit differential potential to induce mitochondrial dysfunction and apoptosis in human granulosa cells.

Bisphenol A (BPA) is an endocrine disruptor strongly associated with ovarian dysfunction. BPA is being substituted by structurally similar chemicals, such as bisphenol S (BPS), bisphenol F (BPF), and bisphenol AF (BPAF). However, the toxicity of these analogues in female reproduction remains largely unknown. This study evaluated the effects of BPA and its analogues BPS, BPF, and BPAF on the mitochondrial mass and function, oxidative stress, and their potential to induce apoptosis of human granulosa cells (KGN cells). BPA and its analogues, especially BPA and BPAF, significantly decreased mitochondrial activity and cell viability. The potential of bisphenols to reduce mitochondrial mass and function differed in the following order: BPAF > BPA > BPF > BPS. Flow cytometry revealed that exposure to bisphenols significantly increased mitochondrial ROS levels and increased mitochondrial Ca2+ levels. Thus, bisphenols exposure causes mitochondrial stress in KGN cells. At the same time, bisphenols exposure significantly induced apoptosis. These results thus emphasize the toxicity of these bisphenols to cells. Our study suggests the action mechanism of BPA and its analogues in damage caused to ovarian granulosa cells. Additionally, these novel analogues may be regrettable substitutes, and the biological effects and potential risks of BPA alternatives must be evaluated.

Paxillin regulates androgen receptor expression associated with granulosa cell focal adhesions.

Paxillin is a ubiquitously expressed adaptor protein integral to focal adhesions, cell motility, and apoptosis. Paxillin has also recently been implicated as a mediator of nongenomic androgen receptor (AR) signaling in prostate cancer and other cells. We sought to investigate the relationship between paxillin and AR in granulosa cells (GCs), where androgen actions, apoptosis, and focal adhesions are of known importance, but where the role of paxillin is understudied. We recently showed that paxillin knockout in mouse GCs increases fertility in older mice. Here, we demonstrate that paxillin knockdown in human granulosa-derived KGN cells, as well as knockout in mouse primary GCs, results in reduced AR protein but not reduced mRNA expression. Further, we find that both AR protein and mRNA half-lives are reduced by approximately one-third in the absence of paxillin, but that cells adapt to chronic loss of paxillin by upregulating AR gene expression. Using co-immunofluorescence and proximity ligation assays, we show that paxillin and AR co-localize at the plasma membrane in GCs in a focal adhesion kinase-dependent way, and that disruption of focal adhesions leads to reduced AR protein level. Our findings suggest that paxillin recruits AR to the GC membrane, where it may be sequestered from proteasomal degradation and poised for nongenomic signaling, as reported in other tissues. To investigate the physiological significance of this in disorders of androgen excess, we tested the effect of GC-specific paxillin knockout in a mouse model of polycystic ovary syndrome (PCOS) induced by chronic postnatal dihydrotestosterone (DHT) exposure. While none of the control mice had estrous cycles, 33% of paxillin knockout mice were cycling, indicating that paxillin deletion may offer partial protection from the negative effects of androgen excess by reducing AR expression. Paxillin-knockout GCs from mice with DHT-induced PCOS also produced more estradiol than GCs from littermate controls. Thus, paxillin may be a novel target in the management of androgen-related disorders in women, such as PCOS.

Bergenin attenuates triptolide-caused premature ovarian failure in mice based on the antioxidant activity.

Tripterygium wilfordii (TW) preparations have been utilized in China for treating rheumatoid arthritis and autoimmune diseases. However, their clinical use is limited due to reproductive toxicity, notably premature ovarian failure (POF). Our study aimed to investigate the effect and mechanism of bergenin in attenuating POF induced by triptolide in mice. POF was induced in female ICR mice via oral triptolide administration (50 µg/kg) for 60 days. Mice received bergenin (25, 50, 100 mg/kg, i.g.) or estradiol valerate (EV) (0.1 mg/kg, i.g.) daily, 1 h before triptolide treatment. In vitro, ovarian granulosa cells (OGCs) were exposed to triptolide (100 nM) and bergenin (1, 3, 10 µM). Antioxidant enzyme activity, protein expression, apoptosis rate, and reactive oxygen species (ROS) levels were assessed. The results showed that triptolide-treated mice exhibited evident atrophy, along with an increase in atretic follicles. Bergenin (50, 100 mg/kg) and EV (0.1 mg/kg), orally administered, exerted significant anti-POF effect. Bergenin and EV also decreased apoptosis in mouse ovaries. In vitro, bergenin (1, 3, 10 µM) attenuated triptolide-induced OGCs apoptosis by reducing levels of apoptosis-related proteins. Additionally, bergenin reduced oxidative stress through downregulation of antioxidant enzymes activity and overall ROS levels. Moreover, the combined use with Sh-Nrf2 resulted in a reduced protection of bergenin against triptolide-induced apoptosis of OGCs. Together, bergenin counteracts triptolide-caused POF in mice by inhibiting Nrf2-mediated oxidative stress and preventing OGC apoptosis. Combining bergenin with TW preparations may effectively reduce the risk of POF.