Melatonin improves the quality of rotenone-exposed mouse oocytes through association with histone modifications.

Rotenone, an insecticide that inhibits mitochondrial complex I and generates oxidative stress, is responsible for neurological disorders and affects the female reproductive system. However, the underlying mechanism is not fully understood. Melatonin, a potential free-radical scavenger, has been shown to protect the reproductive system from oxidative damage. In this study, we investigated the impact of rotenone on mouse oocyte quality and evaluated the protective effect of melatonin on oocytes exposed to rotenone. Our results showed that rotenone impaired mouse oocyte maturation and early embryo cleavage. However, melatonin prevented these negative effects by ameliorating rotenone-induced mitochondrial dysfunction and dynamic imbalance, intracellular Ca2+ homeostasis damage, ER stress, early apoptosis, meiotic spindle formation disruption, and aneuploidy in oocytes. Additionally, RNA sequencing analysis showed that rotenone exposure changed the expression of multiple genes involved in histone methylation and acetylation modifications that result in mouse meiotic defects. However, melatonin partially rescued these defects. These findings suggest that melatonin has protective effects against rotenone-induced mouse oocyte defects.

Erratum: Mir-484 contributes to diminished ovarian reserve by regulating granulosa cell function via YAP1-mediated mitochondrial function and apoptosis: Erratum.

[This corrects the article DOI: 10.7150/ijbs.68028.].

miR-484 mediates oxidative stress-induced ovarian dysfunction and promotes granulosa cell apoptosis via SESN2 downregulation.

Ovarian dysfunction is a common cause of female infertility, which is associated with genetic, autoimmune and environmental factors. Granulosa cells (GCs) constitute the largest cell population of ovarian follicles. Changes in GCs, including oxidative stress (OS) and excessive reactive oxygen species (ROS), are involved in regulating ovary function. miR-484 is highly expressed in 3-NP-induced oxidative stress models of ovaries and GCs. miR-484 overexpression aggravated GCs dysfunction and thereby intensified ovarian oxidative stress injury in mice. Moreover, bioinformatic analyses, luciferase assays and pull-down assays indicated that LINC00958 acted as a competing endogenous RNA (ceRNA) for miR-484 and formed a signaling axis with Sestrin2(SESN2) under oxidative stress conditions, which in turn regulated mitochondrial functions and mitochondrial-related apoptosis in GCs. Additionally, the inhibition of miR-484 alleviated GCs dysfunction under ovarian oxidative stress condition. Our present study revealed the role of miR-484 in oxidative stress of ovaries and GCs and the function of LINC00958/miR-484/SESN2 axis in mitochondrial function and mitochondria-related apoptosis.

RNA binding protein IGF2BP1 meditates oxidative stress-induced granulosa cell dysfunction by regulating MDM2 mRNA stability in an m6A-dependent manner.

Both genetic and microenvironmental detrimental factors are involved in ovarian dysfunction, leading to the increasing rate of involuntary childlessness in recent years. Oxidative stress (OS), which is characterized by the imbalance of redox system with redundant reactive oxygen species (ROS) overwhelming the antioxidant defense, is regarded as one of the culprits of ovarian dysfunction. OS causes damage to various types of ovarian cells including granulosa cells (GCs), jeopardizing the ovarian microenvironment, disturbing follicular development and participating in various female reproductive disorders. However, the specific molecular pathological mechanisms underlying this process have not been fully elucidated. In this study, we found that 3-nitropropionic acid (3-NP) treatment led to significant IGF2BP1 downregulation via, at least partially, inducing ROS overproduction. IGF2BP1 regulates GCs viability, proliferation, cell cycle and cellular senescence by enhancing MDM2 mRNA stability in an m6A-dependant manner. IGF2BP1 overexpression partially rescued 3-NP induced GCs damages, while ectopically expressed MDM2 alleviated both 3-NP or IGF2BP1-knockdown induced GCs dysfunction. These results reveal an epigenetic molecular mechanism underlying OS-related GCs disorders, which may help to establish a novel potential clinical marker for predicting the GCs status as well as the follicular developmental potential.

Paternal cadmium exposure affects testosterone synthesis by reducing the testicular cholesterol pool in offspring mice.

Cadmium（Cd） is a heavy metal that is harmful to human health. Early studies have shown that cadmium can damage testicular structure, affecting testosterone synthesis and spermatogenesis. However, the effect of paternal Cd exposure on the reproductive system of offspring remains unclear. In this study, male 8-week C57BL/6 J mice were used as research objects, and Cd was injected intraperitoneally every other day at a dose of 1 mg/kg for 5 weeks, after which the effect on the reproductive system of offspring male mice was studied. Our results showed that the body weight of the offspring male mice increased faster, with increases of the testicular and epididymis indices under Cd exposure. At the same time, the serum testosterone and free cholesterol decreased, total cholesterol increased, and the sperm concentration decreased. Further qRT-PCR and western blot analyses showed that the expressions of StAR, P450scc, 3ß-HSD and 17ß-HSD, which are related to testosterone synthesis, was significantly downregulated. Additionally, ATGL, LDLR and SR-BI, which are related to the intracellular cholesterol pool were downregulated, leading to the reduction of the cholesterol pool and the accumulation of lipid droplets. Oil red O and BODIPY staining revealed an increase in the abundance of lipid droplets in testicular tissue of newborn and adult mice. Prediction of tsRNA target genes in the sperm of parents and testicular transcriptome of newborn mice showed that the differentially expressed genes were associated with catabolism of fatty acids, cholesterol and ion channels, while the mitochondrial and lysosome functions of testicular tissue of adult offspring mice were decreased. Overall, our results suggest that paternal Cd exposure reduced the intracellular cholesterol pool of testicular of offspring, affected testosterone synthesis and reproductive system development.

Case report: Birth achieved after effective ovarian stimulation combined with dexamethasone in a patient with resistant ovary syndrome.

BACKGROUND: Resistant ovary syndrome (ROS) is a rare endocrine disorder and there have been few reports of live births by affected patients. As gonadotropin resistance leads immature oocytes, some researchers reported few live births with in vitro maturation (IVM) of oocytes, but IVM is not always successful in ROS patients. Here, we report an original case of ROS, associated with Ig-FSHR in the serum, who achieved a live birth following ovarian stimulation combined with dexamethasone treatment. CASE PRESENTATION: The 30-year-old woman presented with secondary amenorrhea and infertility. Her serum FSH levels were found to be higher than normal, but in discordance with a normal anti-Müllerian hormone (AMH) level and antral follicle count. Genetic investigation found no mutations potentially affecting FSHR. With reference of previous ROS studies, the patient's serum was analyzed for antibodies directed against FSHR and dot blot analysis showed strong reactivity with FSHR. Then, dexamethasone was proposed to the patient, and she successfully became pregnant, finally delivering a healthy girl by caesarean section. CONCLUSION: To our best knowledge, this is the first report of the successful treatment of ROS using ovarian stimulation combined with dexamethasone. In some cases of ROS, high doses of exogenous gonadotropins in combination with immunosuppressive therapy could be an effective approach.

Mir-484 contributes to diminished ovarian reserve by regulating granulosa cell function via YAP1-mediated mitochondrial function and apoptosis.

Women with diminished ovarian reserve (DOR) have reduced fertility, but the underlying regulation of ovarian function remains unknown. Although differential microRNA (miRNA) expression has been described in several ovarian disorders, little is known about the role of miRNAs in the pathogenesis of DOR. In this study, we investigated the expression levels of miR-484 in granulosa cells (GCs) derived from human follicular fluid, and explored their correlation with female ovarian reserve function as well as clinical outcomes of assisted reproduction technology (ART). Additionally, we investigated the effects of miR-484 on the biological functions of GC cell lines in vitro. We found that miR-484 was highly expressed in GCs from DOR patients and was correlated with decreasing AMH levels and AFC, as well as increasing FSH levels, but not with LH, progesterone, or estradiol. Additionally, miR-484 was negatively related to the number of retrieved oocytes and the ratio of high-quality embryos. Moreover, we found that miR-484 repressed the proliferation of GCs and induced apoptosis, which can in part be attributed to mitochondrial dysfunction. Conversely, silencing miR-484 had the opposite effect. Multiple approaches, including bioinformatic analysis, RNA-seq, qPCR, immunofluorescence, western blotting and luciferase reporter assays, identified YAP1 as a direct target of miR-484 in GCs. Additionally, reintroduction of YAP1 rescued the effects of miR-484 in GCs. The present study indicates that miR-484 can directly target the mRNA of YAP1, induce mitochondrial dysfunction, and consequently reduce the viability and promote the apoptosis of granulosa cells, which contributes to the pathogenesis of DOR.

N6-Methyladenosine Modifications in the Female Reproductive System: Roles in Gonad Development and Diseases.

N6-methyladenosine (m6A) is the most prevalent chemical modification in eukaryotic messenger RNAs. By participating in various RNA-related bioprocesses including RNA decay, splicing, transport and translation, m6A serves as a pivotal regulator of RNA fate and plays an irreplaceable role in cellular activities. The m6A modifications of transcripts are coordinately regulated by methyltransferase "writers" and demethylase "erasers", and produce variable effects via different m6A reading protein "readers". There is emerging evidence that m6A modifications play a critical role in a variety of physiological and pathological processes in the female reproductive system, subsequently affecting female fertility. Here, we introduce recent advances in research on m6A regulators and their functions, then highlight the role of m6A in gonad development and female reproductive diseases, as well as the underlying mechanisms driving these processes.