DDX04+ Stem Cells in the Ovaries of Postmenopausal Women: Existence and Differentiation Potential.

Ovarian aging is a pacemaker with multiple organ dysfunction. Recently, stem cells with the ability to generate new oocytes have been identified, which provides the possibility of stem cell therapy for ovarian aging. Several studies have revealed the existence of stem cells in the human postmenopausal ovary. In this study, we describe a new method using magnetic-activated cell sorting combined with differential adhesion to isolate DDX4+ stem cells from ovaries of postmenopausal women and show that the cells exhibit similar gene expression profiles and growth characteristics with primitive germ cells. Furthermore, the DDX4+ stem cells could enter the meiosis stage and differentiation into oocytes. The RNA-seq data of the differentiated oocytes shows that mitochondrial metabolism may play an important role in the oogenesis process of the DDX4+ stem cells. Through using the human ovarian cortical fragments transplantation model, we indicated that the GFP-DDX4+ stem cells differentiated into some GFP positive oocyte-like structure in vivo. Our study provided a new method for the isolation of DDX4+ stem cells from the ovaries of postmenopausal women and confirmed the ability of these stem cells to differentiate into oocytes.

MiR-145 regulates steroidogenesis in mouse primary granulosa cells by targeting Arpc5 and subsequent cytoskeleton remodeling.

MicroRNA (miR)-145 is enriched in the follicular granulosa cells (GCs) of 3-week-old mice. Downregulating miR-145 inhibits the proliferation and differentiation of GCs and induces evident changes in their cytoskeleton. In this study, we examined how miR-145 induces cytoskeletal changes in mouse GCs and its potential mechanism in regulating GC steroidogenesis. We found that actin related protein 2/3 complex subunit 5 (Arpc5) is a target of miR-145. The miR-145 antagomir increased ARPC5 expression but not ß-ACTIN, ß-TUBULIN, and PAXILLIN expression. Arpc5 overexpression inhibited GC proliferation, differentiation, and progesterone synthesis. Furthermore, the expression of progesterone synthesis-associated enzymes was downregulated in the Arpc5 overexpression group, and the GC cytoskeleton exhibited evident changes. We conclude that Arpc5, a new target of miR-145, regulates primary GC proliferation and progesterone production by regulating the cytoskeleton remodeling.

Chronic exposure to propylparaben at the humanly relevant dose triggers ovarian aging in adult mice.

Parabens, a type of endocrine-disrupting chemicals, are widely used as antibacterial preservatives in food and cosmetics in daily life. Paraben exposure has gained particular attention in the past decades, owing to its harmful effects on reproductive function. Whether low-dose paraben exposure may cause ovarian damage has been ignored recently. Here, we investigated the effects of chronic low-dose propylparaben (PrPB) exposure on ovarian function. Female C57BL/6J mice were exposed to PrPB at a humanly relevant dose for 8 months. Our results showed that chronic exposure to PrPB at a humanly relevant dose significantly altered the estrus cycle, hormone levels, and ovarian reserve, accelerating ovarian aging in adult mice. These effects are accompanied by oxidative stress enrichment, leading to steroidogenesis dysfunction and acceleration of primordial follicle recruitment. Notably, melatonin supplementation has been shown to protect against PrPB-induced steroidogenesis dysfunction in granulosa cells. Here, we report that daily chronic PrPB exposure may contribute to ovarian aging by altering oxidative stress-mediated JNK and PI3K-AKT signaling regulation, and that melatonin may serve as a pharmaceutical candidate for PrPB-associated ovarian dysfunction.

The inhibition of WIP1 phosphatase accelerates the depletion of primordial follicles.

RESEARCH QUESTION: What role does wild-type p53-induced phosphatase 1 (WIP1) play in the regulation of primordial follicle development? DESIGN: WIP1 expression was detected in the ovaries of mice of different ages by western blotting and immunohistochemical staining. Three-day-old neonatal mouse ovaries were cultured in vitro with or without the WIP1 inhibitor GSK2830371 (10 µM) for 4 days. Ovarian morphology, follicle growth and follicle classification were analysed and the PI3K-AKT-mTOR signal pathway and the WIP1-p53-related mitochondrial apoptosis pathway evaluated. RESULTS: WIP1 expression was downregulated with age. Primordial follicles were significantly decreased in the GSK2830371-treated group, without a significant increase in growing follicles. The ratio of growing follicles to primordial follicles was not significantly different between the control and GSK2830371 groups, and no significant variation was observed in the PI3K-AKT-mTOR signal pathway. The inhibition of WIP1 phosphatase accelerated primordial follicle atresia by activating the p53-BAX-caspase-3 pathway. CONCLUSIONS: These findings reveal that WIP1 participates in regulating primordial follicle development and that inhibiting WIP1 phosphatase leads to massive primordial follicle loss via interaction with the p53-BAX-caspase-3 pathway. This might also provide valuable information for understanding decreased ovarian reserve during ovarian ageing.

Ovarian Dysfunction Induced by Chronic Whole-Body PM2.5 Exposure.

Fine particulate matter (PM2.5) pollution arouses public health concerns over the world. Increasing epidemiologic evidence suggests that exposure to ambient airborne PM2.5 increases the risk of female infertility. However, relatively few studies have systematically explored the harmful effect of chronic PM2.5 exposure on ovarian function and the underlying mechanisms. In this study, female C57BL/6J mice are exposed to filtered air or urban airborne PM2.5 for 4 months through a whole-body exposure system. It is found that PM2.5 exposure significantly caused the alteration of estrus cycles, reproductivity, hormone levels, and ovarian reserve. The granulosa cell apoptosis via the mitochondria dependent pathway contributes to the follicle atresia. With RNA-sequencing technique, the differentially expressed genes induced by PM2.5 exposure are mainly enriched in ovarian steroidogenesis, reactive oxygen species and oxidative phosphorylation pathways. Furthermore, it is found that increased PM2.5 profoundly exacerbated ovarian oxidative stress and inflammation in mice through the NF-κB/IL-6 signaling pathway. Notably, dietary polydatin (PD) supplement has protective effect in mice against PM2.5-induced ovarian dysfunction.These striking findings demonstrate that PM2.5 and/or air pollution is a critical factor for ovarian dysfunction through mitochondria-dependent and NF-κB/IL-6-mediated pathway, and PD may serve as a pharmaceutic candidate for air pollution-associated ovarian dysfunction.

Suppression of SEMA6C promotes preantral follicles atresia with decreased cell junctions in mice ovaries.

Mammalian oocytes go through a long and complex developmental process, while acquiring the competencies that are required for fertilization and embryogenesis. Recent studies revealed that the communication between oocytes and granulosa cells (GCs) is a critical process for female follicle development. In the current study, we aimed to study whether and how semaphorin 6C (Sema6c) regulated the cell junctions between oocytes and GCs in mice preantral follicles. The attenuation of SEMA6C expression by siRNA decreased the cell-cell junctions and accelerated follicle atresia in vitro. PI3K-AKT pathway was activated when SEMA6C expression was downregulated. And the LY294002, a PI3K inhibitor, could reverse the effect of low SEMA6C expression on cell junctions in preantral follicles. Our findings revealed that Sema6c was involved in follicle development, and the suppression of SEMA6C led to cell junction defection by activating the PI3K/AKT pathway, which might also provide valuable information for understanding premature ovarian failure and ovarian aging.

CCL5 secreted by senescent theca-interstitial cells inhibits preantral follicular development via granulosa cellular apoptosis.

As a fundamental aging mechanism, cellular senescence causes chronic inflammation via the senescence-associated secretory phenotype (SASP). Theca-interstitial cells are an essential but little-studied component of follicle development in the ovarian microenvironment. In the present study, we observed significant cellular senescence in theca-interstitial cells and secretion of chemokine (C-C motif) ligand 5 (CCL5) by these cells during aging. Furthermore, we aimed to investigate whether and how senescence-associated secretory phenotype (SASP)-associated CCL5 may be involved in follicle development. Increased levels of CCL5 in the microenvironment of follicles attenuated preantral follicle growth, survival, and estradiol secretion. Oocyte maturation and the expression of zona pellucida 3 and differentiation factor 9 (GDF9) were also inhibited by CCL5. Granulosa cell apoptosis in follicles was promoted by CCL5, accompanied by the phosphorylation of nuclear factor-κB by CCL5 and inhibition of the PI3K/AKT pathway. These results suggest that SASP-associated CCL5 produced by senescent theca-interstitial cells may impair follicle development and maturation during ovarian aging by promoting granulosa cell apoptosis.

Low expression of SEMA6C accelerates the primordial follicle activation in the neonatal mouse ovary.

The primordial follicle assembly, activation and the subsequent development are critical processes for female reproduction. A limited number of primordial follicles are activated to enter the growing follicle pool each wave, and the primordial follicle pool progressively diminishes over a woman's life-time. The number of remaining primordial follicles represents the ovarian reserve. Identification and functional investigation of the factors involved in follicular initial recruitment will be of great significance to the understanding of the female reproduction process and ovarian ageing. In this study, we aimed to study whether and how semaphorin 6C (Sema6c) regulated the primordial follicle activation in the neonatal mouse ovary. The attenuation of SEMA6C expression by SiRNA accelerated the primordial follicle activation in the in vitro ovary culture system. PI3K-AKT-rpS6 pathway was activated when SEMA6C expression was down-regulated. And the LY294002 could reverse the effect of low SEMA6C expression on primordial follicle activation. Our findings revealed that Sema6c was involved in the activation of primordial follicles, and the down-regulation of SEMA6C led to massive primordial follicle activation by interacting with the PI3K-AKT-rpS6 pathway, which might also provide valuable information for understanding premature ovarian failure and ovarian ageing.

Enrichment of Female Germline Stem Cells from Mouse Ovaries Using the Differential Adhesion Method.

BACKGROUND/AIMS: The isolation and establishment of female germline stem cells (FGSCs) is controversial because of questions regarding the reliability and stability of the isolation method using antibody targeting mouse vasa homologue (MVH), and the molecular mechanism of FGSCs self-renewal remains unclear. Thus, there needs to be a simple and reliable method for sorting FGSCs to study them. METHODS: We applied the differential adhesion method to enrich FGSCs (DA-FGSCs) from mouse ovaries. Through four rounds of purification and 7-9 subsequent passages, DA-FGSC lines were established. In addition, we assessed the role of the phosphoinositide-3 kinase (PI3K)-AKT pathway in regulating FGSC self-renewal. RESULTS: The obtained DA-FGSCs spontaneously differentiated into oocyte-like cells in vitro and formed functional eggs in vivo that were fertilized and produced healthy offspring. AKT was rapidly phosphorylated when the proliferation rate of FGSCs increased after 10 passages, and the addition of a chemical PI3K inhibitor prevented FGSCs self-renewal. Furthermore, over-expression of AKT-induced proliferation and differentiation of FGSCs, c-Myc, Oct-4 and Gdf-9 levels were increased. CONCLUSIONS: The differential adhesion method provides a more feasible approach and is an easier procedure to establish FGSC lines than traditional methods. The AKT pathway plays an important role in regulation of the proliferation and maintenance of FGSCs. These findings could help promote stem cell studies and provide a better understanding of causes of ovarian infertility, thereby providing potential treatments for infertility.

Isolation and identification of ovarian theca-interstitial cells and granulose cells of immature female mice.

Theca-interstitial cells (TICs) and granulosa cells (GCs) are important components of follicles that support follicle development and hormone secretion, and are considered to be important cell models for basic research. However, no method currently exists for simultaneously isolating TICs and GCs from a single ovary of the immature mouse. Here, we sought to develop such a protocol using mechanical dissection combined with brief collagenase-DNase digestion. Morphological characteristics and molecular markers were detected to identify TICs and GCs. In isolated TICs, cholesterol side chain cleavage cytochrome P450 (P450scc) was expressed abundantly, but anti-Mullerian hormone (AMH) was expressed only at very low levels. This expression profile was reversed in GCs. In addition, TICs secreted large amounts of testosterone (T) and minimal amounts of estradiol (E2 ), while the converse was found in GCs. T concentrations rose gradually in TIC culture media as the concentration of added luteinizing hormone (LH) was increased. In GCs, E2 secretion increased as the follicle-stimulating hormone (FSH) concentration increased. Thus, mechanical dissection combined with collagenase-DNase digestion is a simple, effective and reproducible method for obtaining large numbers of highly purified and hormonally stimulated TICs and GCs from one ovary.

Phthalates and uterine disorders.

Humans are ubiquitously exposed to environmental endocrine disrupting chemicals such as phthalates. Phthalates can migrate out of products and enter the human body through ingestion, inhalation, or dermal application, can have potential estrogenic/antiestrogenic and/or androgenic/antiandrogenic activity, and are involved in many diseases. As a female reproductive organ that is regulated by hormones such as estrogen, progesterone and androgen, the uterus can develop several disorders such as leiomyoma, endometriosis and abnormal bleeding. In this review, we summarize the hormone-like activities of phthalates, in vitro studies of endometrial cells exposed to phthalates, epigenetic modifications in the uterus induced by phthalate exposure, and associations between phthalate exposure and uterine disorders such as leiomyoma and endometriosis. Moreover, we also discuss the current research gaps in understanding the relationship between phthalate exposure and uterine disorders.

Expression patterns and regulatory functions of microRNAs during the initiation of primordial follicle development in the neonatal mouse ovary.

The initiation of primordial follicle development is essential for female fertility, but the signals that trigger this process are poorly understood. Given the potentially important roles of microRNAs (miRNAs) in the ovary, we aimed to study the expression patterns and regulatory functions of miRNAs during the initiation of primordial follicle development. Expression patterns of miRNA in the neonatal mouse ovary were profiled by microarray, and 24 miRNAs whose abundances differed significantly between ovaries from 3- and 5-day-old mice were identified. Pathway enrichment analysis revealed that 48 signal transduction pathways are modulated by the up-regulated miRNAs and 29 pathways are modulated by the down-regulated miRNAs (P-value and false discovery rate < 0.001). A miRNA-mRNA regulatory network was established for TGF-beta signaling pathway-related genes. Among the miRNAs involved in this pathway, miR-145 was chosen for further analysis. Down-regulation of miR-145 using an antagomir (AT) decreased the proportion and number of the primordial follicles and increased that of the growing follicles in the cultured ovaries (P < 0.05). The mean oocyte diameter in the primordial follicles was significantly greater in the AT group relative to the AT-negative control group (P < 0.05), whereas the mean oocyte diameter in growing follicles was smaller in the AT group than in the AT-negative control group. In addition, we confirmed that miR-145 targets Tgfbr2. The miR-145 AT caused an increase in TGFBR2 expression and activation of Smad signaling but did not affect the p38 MAPK or JNK pathway. These data suggest that miRNAs and the signaling pathways they modulate are involved in the initiation of primordial follicle development, and miR-145 targets Tgfbr2 to regulate the initiation of primordial follicle development and maintain primordial follicle quiescence.

Effects of culture and transplantation on follicle activation and early follicular growth in neonatal mouse ovaries.

Mouse models have been widely utilized to elucidate the basic principles and regulatory mechanisms of primordial follicle activation. Outside their natural environment, the growth of follicles might be affected by unknown factors in vitro and the elimination of regulation in vivo. Currently, in vitro culture and transplantation of ovaries under the kidney capsule are two commonly used incubation methods. However, the limited number of studies that have been published compare various incubation systems and reveal differences between ovaries that are incubated and grown in vivo. We compare the number of primordial, primary and secondary follicles in cultured, transplanted and in-vivo-grown ovaries. We investigate the expression levels of four genes, including zona pellucida 3 (ZP3), growth and differentiation factor-9 (GDF-9), proliferating cell nuclear antigen (PCNA) and anti-Müllerian hormone (AMH). Our results suggest that in vitro culture accelerates follicle activation, delays the transition from primary to secondary follicles and affects the expression patterns of ZP3, GDF-9, PCNA and AMH. A larger number of secondary follicles in ovaries cultured in alpha-minimal essential medium (α-MEM) had intact zona pellucida compared with those grown in Dulbecco's modified Eagle medium containing Ham's F-12 nutrient mixture (D/F12), suggesting that α-MEM is a better basal medium. The transplanted ovaries demonstrated the most similar characteristics to the in-vivo-grown ovaries, indicating that transplantation provided an optimal environment for ovarian incubation. This study has thus established the similarities and differences between in-vivo-grown and incubated ovaries, demonstrated that transplantation can mostly mimic the environment of ovarian growth in vivo and determined the optimal basal culture medium between α-MEM and D/F12.

Changes of endocrine and ultrasound markers as ovarian aging in modifying the Stages of Reproductive Aging Workshop (STRAW) staging system with subclassification of mid reproductive age stage.

OBJECTIVE: To demonstrate the changes of ovarian aging markers across the Stages of Reproductive Aging Workshop (STRAW) stages and modify it with subclassification of mid reproductive age stage (MR). DESIGN: Healthy females were classified according to the STRAW system. Serum basal FSH, LH, E2, and anti-Müllerian hormone (AMH) were detected, FSH/LH ratio calculated, and antral follicle counts (AFCs) determined in follicular phase. RESULTS: Progression through the whole STRAW stages under MR stage subdivided is associated with elevations in FSH, LH, FSH/LH ratio and decreases in E2, AMH and AFCs (p < 0.001). Both serum AMH and AFCs decreased early (after 25 years) and significantly (p < 0.01) with chronological age in MR stage. 0.982 ng/ml AMH and 3 antral follicles (low level of MR 25-30 years) were set as cutoffs to distinguish MR stage into early mid reproductive age (EMR) and late mid reproductive age (LMR) stages. The women in EMR stage compared with LMR could retrieve more oocytes in IVF treatment (p < 0.05) and has a higher pregnancy chance (57.9%) though not significant. CONCLUSION(S): The early and marked fall in serum AMH levels and AFCs suggest fine markers to further categorize and define the MR stage, demonstrating disparate reproductive aging period with reduced ovarian reserve in young age across the STRAW stages.

[Protective effects of caloric restriction on ovarian function].

OBJECTIVE: To study the protective effects on ovarian function by caloric restriction (CR) and its mechanism. METHODS: Thirty female C57BL/6 mice of 8 weeks old were randomly divided into two groups, including ad libitum (AL) group and caloric restriction (CR) group. The general situation and ovarian function of those mice were compared and evaluated.Ovarian follicles were counted by hematoxylin-eosin staining. Anti-Miillerian Hormone(AMH) mRNA expression of the ovary were detected by using real-time PCR. The concentrations of serum estradiol, progesterone of the mice were measured by ELISA. And the fertility of mice by mating trials were evaluated, SIRT3, Hypoxia inducible factor 1α (HIF-1α) and catalase (CAT) mRNA expression of the mice ovaries were detected by Real-Time PCR. RESULTS: The total follicles were 546 in CR mice and 286 in AL mice. The proportion of primordial follicles were 38.6% (211/546) in ovaries of CR mice and 29.4% (84/286) in ovaries of AL mice, which reached statistical difference. The proportion of atretic follicles 5.3% (29/546) in ovaries of CR mice, compared with 16.8% (48/286) in AL mice, was significantly decreased (P < 0.05). The AMH mRNA expression in CR mice ovaries was 3.37 times of that of AL mice (P < 0.05). The serum concentration of estradiol in CR mice was up to (5.3 ± 1.6) pmol/L, which was much higher than (3.6 ± 1.6) pmol/L in AL mice. While, the progesterone concentration of (0.4 ± 0.3) nmol/L in CR mice was lower than (1.4 ± 0.8) nmol/L in AL mice (P < 0.05).Fertility and survival of offsprings were both improved in CR mice. The expression level of SIRT3 mRNA in CR mice ovary was 1.39 times, CAT was 1.55 times and HIF-1α was 0.31 times of those in AL mice (P < 0.05). CONCLUSIONS: Caloric restriction can delay the ovary aging process through reduce follicle depletion by suppressing follicle recruitment and ovulation. The function of ovarian reserve and reproductive endocrine was effectively protected. Caloric restriction can reduce the incidence of follicular atresia, its mechanism might be associated with anti-oxidative stress.

The stromal microenvironment and ovarian aging: mechanisms and therapeutic opportunities.

For decades, most studies of ovarian aging have focused on its functional units, known as follicles, which include oocytes and granulosa cells. However, in the ovarian stroma, there are a variety of somatic components that bridge the gap between general aging and ovarian senescence. Physiologically, general cell types, microvascular structures, extracellular matrix, and intercellular molecules affect folliculogenesis and corpus luteum physiology alongside the ovarian cycle. As a result of damage caused by age-related metabolite accumulation and external insults, the microenvironment of stromal cells is progressively remodeled, thus inevitably perturbing ovarian physiology. With the established platforms for follicle cryopreservation and in vitro maturation and the development of organoid research, it is desirable to develop strategies to improve the microenvironment of the follicle by targeting the perifollicular environment. In this review, we summarize the role of stromal components in ovarian aging, describing their age-related alterations and associated effects. Moreover, we list some potential techniques that may mitigate ovarian aging based on their effect on the stromal microenvironment.

Efficacy and Safety of the Chinese Herbal Compound TJAOA101 in Treating Diminished Ovarian Reserve: A Protocol for Multicenter, Prospective, and Pre-Post Study.

OBJECTIVE: Diminished ovarian reserve (DOR) can lead to early menopause, poor fecundity, and an increased risk of disorders such as osteoporosis, cardiovascular disease, and cognitive impairment, seriously affecting the physical and mental health of women. There is still no safe and effective strategy or method to combat DOR. We have developed a novel Chinese herbal formula, Tongji anti-ovarian aging 101 (TJAOA101), to treat DOR. However, its safety and efficacy need to be further validated. METHODS: In this prospective and pre-post clinical trial, 100 eligible patients aged 18-45 diagnosed with DOR will be recruited. All participants receive TJAOA101 twice a day for 3 months. Then, comparisons before and after treatment will be analyzed, and the outcomes, including anti-mullerian hormone (AMH) and follicle-stimulating hormone (FSH) levels and the antral follicle count (AFC), the recovery rate of menopause, and the Kupperman index (KMI), will be assessed at baseline, every month during medication (the intervention period), and 1, 3 months after medication (the follow-up period). Assessments for adverse events will be performed during the intervention and follow-up periods. CONCLUSION: A multicenter, prospective study will be conducted to further confirm the safety and efficacy of TJAOA101 in treating DOR and to provide new therapeutic strategies for improving the quality of life in DOR patients.

Vaginal Microbiota Changes in Patients With Premature Ovarian Insufficiency and Its Correlation With Ovarian Function.

Objectives: To reveal the characteristics of vaginal microbiota in premature ovarian insufficiency (POI) patients and their relationship with ovarian function. Materials and Methods: In this case-control study, the vaginal bacterial composition of 30 POI patients and 26 healthy women of comparable age was assessed by 16S rRNA gene sequencing targeting the V3-V4 hypervariable regions. The metabolic functions of vaginal microflora were preliminarily predicted through the PICRUSt2 analysis. Redundancy analysis and Spearman's correlation analyzed the relationships between vaginal microbiota and ovarian function indicators. Results: Actinobacteria, Atopobium, and Gardnerella were significantly increased in POI patients. Their increments were significantly negatively correlated with anti-müllerian hormone (AMH) and inhibin B, and positively correlated with follicle-stimulating hormone (FSH) and luteinizing hormone (LH). While Bifidobacterium was significantly decreased in POI patients. Its relative abundance was significantly positively correlated with AMH and negatively correlated with FSH and LH. Then, POI patients included in this study were divided into POI (25 < FSH ≤ 40) (n = 9) and premature ovarian failure (POF) (FSH > 40) (n = 21) subgroups according to serum FSH levels. Compared with the controls, Firmicutes and Lactobacillus were significantly decreased only in POF (FSH > 40) patients, while no difference was observed in POI (25 < FSH ≤ 40) patients. Lactobacillus was negatively correlated with FSH. Firmicutes was significantly reduced and Actinobacteria was significantly increased in POF (FSH > 40) patients compared with POI (25 < FSH ≤ 40) patients. The key bacterial taxa Gardnerella and Atopobium showed potency in predicting POI. Conclusions: Here we demonstrated significant changes in the vaginal microbiota of POI patients, and these changes were significantly correlated with reduced ovarian reserve, endocrine disruption, and symptoms of perimenopausal syndrome. Differences in vaginal microbiota between POI (25 < FSH ≤ 40) and POF (FSH > 40) patients were also identified. These findings may provide new evidence for the relationship between vaginal microbiota and ovarian function.

Low WIP1 Expression Accelerates Ovarian Aging by Promoting Follicular Atresia and Primordial Follicle Activation.

Our previous study demonstrated that ovarian wild-type P53-induced phosphatase 1 (WIP1) expression decreased with age. We hypothesized that WIP1 activity was related to ovarian aging. The role of WIP1 in regulating ovarian aging and its mechanisms remain to be elucidated. Adult female mice with or without WIP1 inhibitor (GSK2830371) treatment were divided into three groups (Veh, GSK-7.5, GSK-15) to evaluate the effect of WIP1 on ovarian endocrine and reproductive function and the ovarian reserve. In vitro follicle culture and primary granulosa cell culture were applied to explore the mechanisms of WIP1 in regulating follicular development. This study revealed that WIP1 expression in atretic follicle granulosa cells is significantly lower than that in healthy follicles. Inhibiting WIP1 phosphatase activity in mice induced irregular estrous cycles, caused fertility declines, and decreased the ovarian reserve through triggering excessive follicular atresia and primordial follicle activation. Primordial follicle depletion was accelerated via PI3K-AKT-rpS6 signaling pathway activation. In vitro follicle culture experiments revealed that inhibiting WIP1 activity impaired follicular development and oocyte quality. In vitro granulosa cell experiments further indicated that downregulating WIP1 expression promoted granulosa cell death via WIP1-p53-BAX signaling pathway-mediated apoptosis. These findings suggest that appropriate WIP1 expression is essential for healthy follicular development, and decreased WIP1 expression accelerates ovarian aging by promoting follicular atresia and primordial follicle activation.

Peroxiredoxin 2 inhibits granulosa cell apoptosis during follicle atresia through the NFKB pathway in mice.

Peroxiredoxin 2 (PRDX2) has been known to act as an antioxidant enzyme whose main function is H(2)O(2) reduction in cells. We aimed to study the expression patterns of PRDX2 in mouse ovaries and explore the function of this protein in apoptosis of granulosa cells (GCs). We found that the expression of the PRDX2 protein in atretic follicle GCs was markedly higher than in healthy follicle GCs. In vitro, the transfection of siRNA targeting the Prdx2 gene inhibited the proliferation and induced the apoptosis of primary cultured GCs. Furthermore, suppression of PRDX2 resulted in the augmentation of endogenous H(2)O(2), and the ability to eliminate the exogenous H(2)O(2) was attenuated. The expression of PRDX2 and nuclear factor kappa-light-chain-enhancer of activated B cells (NFKB), whose activity was inhibited by binding to IKB, increased in GCs treated with various concentrations of H(2)O(2) for 30 min. However, no significant change in cytoplasmic IKB expression was observed. At 2 h after treatment with H(2)O(2), nuclear NFKB expression level was reduced, cytoplasmic IKB expression was increased, and PRDX2 expression was unchanged. Silencing of the Prdx2 gene caused early changes in NFKB and IKB expression in the primary cultured GCs compared to that in control cells. Taken together, these data suggest that PRDX2 plays an important role in inhibiting apoptosis in GCs and that PRDX2 actions may be related to the expression of NFKB and IKB.