Persistent follicular granulosa cell senescence and apoptosis induced by methotrexate leading to oocyte dysfunction and aberrant embryo development

Cellular senescence in the pathogenesis of ovarian dysfunction

The follicular microenvironment is crucial for normal ovarian function, and intra-ovarian factors, in coordination with gonadotropins, contribute to its regulation. Recent research has revealed that the accumulation of senescent cells worsens the adverse environment of various tissues and plays critical roles in chronological aging and various pathological conditions. Cellular senescence involves cell-cycle arrest, a senescence-associated secretory phenotype (SASP), macromolecular damage, and dysmetabolism. In this review, I summarize the latest knowledge regarding the role of cellular senescence in pathological conditions in the ovary, in the context of reproduction. Specifically, cellular senescence is known to impair follicular and oocyte health in cisplatin- and cyclophosphamide-induced primary ovarian insufficiency and to contribute to the pathogenesis of polycystic ovary syndrome (PCOS). In addition, cellular senescence is induced during the decline in ovarian reserve that is associated with chronological aging, endometriosis, psychological stress, and obesity, but it remains unclear whether it plays a causative role in these conditions. Finally, I discuss the potential for use of cellular senescence as a novel therapeutic target. The modification of SASP using a senomorphic and/or the elimination of senescent cells using a senolytic represent promising therapeutic strategies. Further elucidation of the role of cellular senescence in the effects of various insults on ovarian reserve, including chronological aging, as well as in pathogenesis of ovarian pathologies, including PCOS, may facilitate a new era of reproductive medicine.

Baicalin enhances proliferation and reduces inflammatory-oxidative stress effect in H2O2-induced granulosa cells apoptosis via USP48 protein regulation

BACKGROUND

Oxidative stress and inflammation can lead to apoptosis of ovarian granulosa cells (GCs), resulting in ovulation disorders and infertility. Baicalin (BAI) promotes cell proliferation and reduces inflammation and oxidative stress. However, the mechanisms by which BAI treatment affects oxidative stress and inflammation in GCs remain incompletely understood.

METHODS

KGN cells were treated with hydrogen peroxide (H2O2) to analyze the effect of oxidative stress on GCs in vitro. Subsequently, H2O2-stimulated KGN cells were treated with BAI. The levels of GSH-Px, CAT, and SOD were measured using an activity assay kit. The levels of MDA, IL-1β, IL-6, IL-8, and TNF-α were measured by ELISA. Proliferation, apoptosis, and mRNA and protein levels were measured using the CCK8, flow cytometry, qRT-PCR, and western blotting.

RESULTS

H2O2 treatment inhibited KGN cell proliferation and promoted apoptosis, accompanied by increased oxidative stress and inflammation. BAI promoted proliferation, inhibited apoptosis, and reduced oxidative stress and inflammation in H2O2-stimulated KGN cells. BAI treatment promoted USP48 protein expression, and USP48 knockdown abrogated the protective effects of BAI, indicating that USP48 is a downstream mediator of BAI.

CONCLUSION

BAI treatment enhanced cell proliferation and ameliorated oxidative stress and inflammation by enhancing USP48 protein expression. BAI, which is used clinically and as a dietary supplement, may alleviate oxidative stress-induced GC injury and ovarian disorders.

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.

Identification of transcriptome characteristics of granulosa cells and the possible role of UBE2C in the pathogenesis of premature ovarian insufficiency

BACKGROUND

Premature ovarian insufficiency (POI) is an important cause of infertility characterized by the functional decline of the ovary. Granulosa cells (GCs) around oocytes are critical for folliculogenesis, and GC dysfunction is one of the important etiologies of POI. The aim of this study was to explore the potential biomarkers of POI by identifying hub genes and analyze the correlation of biomarkers with immune infiltration in POI using RNA profiling and bioinformatics analysis.

METHODS

RNA sequencing was performed on GCs from biochemical POI (bPOI) patients and controls. Differential expression analysis and weighted gene co-expression network analysis (WGCNA) were used to explore the candidate genes. qRT‒PCR was performed to verify the expression of hub genes. Western blot, Cell Counting Kit-8, 5-ethynyl-2'-deoxyuridine (EdU) assays, TUNEL (TdT-mediated dUTP Nick-End Labeling) and flow cytometry analysis were used to validate the possible role of ubiquitin-conjugating enzyme 2C (UBE2C) in POI. CIBERSORT was adopted to explore immune cell infiltration and the correlation between UBE2C and immune cells in bPOI.

RESULTS

Through analysis of differentially expressed genes (DEGs) and WGCNA, we obtained 143 candidate genes. After construction of the protein‒protein interaction (PPI) network and analysis with Cytoscape, 10 hub genes, including UBE2C, PBK, BUB1, CDC20, NUSAP1, CENPA, CCNB2, TOP2A, AURKB, and FOXM1, were identified and verified by qRT‒PCR. Subsequently, UBE2C was chosen as a possible biomarker of POI because knockdown of UBE2C could inhibit the proliferation and promote the apoptosis of GCs. Immune infiltration analysis indicated that monocytes and M1 macrophages may be associated with the pathogenesis of POI. In addition, UBE2C was negatively correlated with monocytes and M1 macrophages in POI.

CONCLUSIONS

This study identified a hub gene in GCs that might be important in the pathogenesis of POI and revealed the key role of UBE2C in driving POI. Immune infiltration may be highly related with the onset and etiology of POI.

miR-200b/MYBL2/CDK1 suppresses proliferation and induces senescence through cell cycle arrest in ovine granulosa cells

Normal growth of granulosa cells (GCs) is essential for follicular development. miR-200b plays a vital role in litter size, estrous cycle, ovulation, and follicular development in sheep. However, it is unclear that the specific effect and regulatory mechanism of miR-200b on ovine GCs. miR-200b mimic inhibited GCs proliferation and induced cellular senescence through downregulating mitochondrial membrane potential (MMP), concentration of ATP and mitochondrial respiratory chain complex Ⅰ, and upregulating SA-β-gal positive rate and ROS production. A total of 597 differentially expressed genes were identified by RNA-Seq in GCs transfected with miR-200b mimic and mimic NC, and they were involved in cell cycle and cellular senescence. miR-200b directly targeted and downregulated MYBL2 and CDK1. Overexpression of MYBL2 promoted GCs proliferation and genes expression (CDK1, CDC20, MAD2L1 and FOXM1), which were suppressed by miR-200b mimic. Furthermore, MYBL2 negatively regulated miR-200b-induced GC senescence. In conclusion, miR-200b/MYBL2/CDK1 regulated proliferation and senescence through cell cycle pathway in ovine granulosa cells. Our study provides a novel insight that miR-200b regulates ovine follicular development.

Advances in Oocyte Maturation In Vivo and In Vitro in Mammals

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

Potential Gonado-Protective Effect of Cichorium endivia and Its Major Phenolic Acids against Methotrexate-Induced Testicular Injury in Mice

Cichorium endivia L. (Asteraceae) is a wide edible plant that grows in the Mediterranean region. In this study, a phytochemical investigation of C. endivia L. ethanolic extract led to the isolation of stigmasterol (1), ursolic acid (2), β-amyrin (3), azelaic acid (4), vanillic acid (5), (6S, 7E)-6-hydroxy-4,7-megastigmadien-3,9-dione (S(+)-dehydrovomifoliol) (6), 4-hydroxy phenyl acetic acid (7), vomifoliol (8), ferulic acid (9), protocatechuic acid (10), kaempferol (11), p. coumaric acid (12), and luteolin (13). In addition, the total phenolic content as well as the in vitro antioxidant activity of C. endivia L. extract were estimated. Moreover, we inspected the potential gonado-protective effect of C. endivia crude extract, its phenolic fraction, and the isolated coumaric, vanillic, and ferulic acids against methotrexate (MTX)-induced testicular injury in mice. There were seven groups: normal control, MTX control, MTX + C. endivia crude extract, MTX + C. endivia phenolic fraction, MTX + isolated coumaric acid, MTX + isolated vanillic acid, and MTX + isolated ferulic acid. MTX was given by i.p. injection of a 20 mg/kg single dose. The crude extract and phenolic fraction were given with a dose of 100 mg/kg/day, whereas the compounds were given at a dose of 10 mg/kg/day. A histopathological examination was done. The testosterone level was detected in serum together with the testicular content of malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), interleukin 1β (IL-1β), IL-6, tumor necrosis factor alpha (TNF-α), nuclear factor kappa B (NF-κB), B-cell lymphoma 2 (Bcl-2), Bcl-2 associated x protein (Bax), p53, and miR-29a. C. endivia crude extract, the phenolic fraction, and the isolated compounds showed significant elevation in their levels of testosterone, CAT, SOD, Bcl-2 with a significant decrease in their levels of MDA, TNF-α, IL-1β, IL-6, NF-κB, Bax, P53, and miR-29a compared to those of the MTX control group. In conclusion, C. endivia mitigated MTX-induced germ cell toxicity via anti-inflammatory, antioxidant, and antiapoptotic effects.

Folic acid Ameliorates the Declining Quality of Sodium Fluoride-Exposed Mouse Oocytes through the Sirt1/Sod2 Pathway

Excessive sodium fluoride (NaF) intake interferes with reproductive function in humans and animals; however, strategies to prevent these effects are still underexplored. Here, we showed that in vivo and in vitro supplementation of folic acid (FA) efficaciously improved the quality of NaF-exposed oocytes. FA supplementation not only increased ovulation of oocytes from NaF-treated mice but also enhanced oocyte meiotic competency and fertilization ability by restoring the spindle/chromosome structure. Moreover, FA supplementation could exert a beneficial effect on NaF- exposed oocytes by restoring mitochondrial function, eliminating reactive oxygen species accumulation to suppress apoptosis. We also found that FA supplementation restored the defective phenotypes in oocytes through a Sirt1/Sod2-dependent mechanism. Inhibition of Sirt1 with EX527 abolished the FA-mediated improvement in NaF-exposed oocyte quality. Collectively, our data indicated that FA supplementation is a feasible approach to protect oocytes from NaF-related deterioration.

Pregnancy outcomes in patients with rheumatoid arthritis who discontinue methotrexate treatment to conceive

INTRODUCTION/OBJECTIVES

Rheumatoid arthritis (RA) develops at reproductive age. Methotrexate (MTX), the anchor drug for RA treatment, is contraindicated during pregnancy. We investigated pregnancy outcomes in RA patients in whom MTX was withdrawn.

METHOD

Pregnancy outcomes, RA treatment, and infertility factors were examined in patients with RA who discontinued MTX prior to attempting conception. The Mann-Whitney U test and Fisher's exact test were used to evaluate differences between the groups.

RESULTS

Of the 52 patients enrolled in this study, 33 gave birth after discontinuing MTX and 19 did not. The age at MTX discontinuation was significantly different between the childbirth and non-childbirth groups (p = 0.0258). The use of non-steroidal anti-inflammatory drugs (NSAIDs) and salazosulfapyridine was significantly different between the groups (p = 0.0079 and p = 0.0438, respectively). Patients whose time from MTX discontinuation to pregnancy was longer than 12 months had a longer previous MTX administration period (p = 0.0182) and were older at the time of pregnancy (p = 0.0128) than those whose was shorter.

CONCLUSIONS

The results suggest that to ensure successful childbirth in women with RA, the decision to conceive should be made at the youngest possible age, NSAIDs should not be used, and a shorter duration of MTX treatment should be considered before pregnancy. Nevertheless, additional studies with larger sample sizes are warranted to analyse the effects of other factors on pregnancies in patients with RA.

KEY POINTS

• Patients with RA who plan to conceive must discontinue MTX therapy. • To achieve successful pregnancy outcomes, female patients with RA should become pregnant when they are young, discontinue NSAIDs prior to conception, and shorten their durations of MTX therapy before attempting pregnancy.