Tumor necrosis factor alpha inhibits ovulation and induces granulosa cell death in rat ovaries

Immunophenotypic profiles and inflammatory markers in Premature Ovarian Insufficiency

Premature Ovarian Insufficiency (POI), also known as Premature Ovarian Failure (POF), is a heterogeneous disorder characterized by the cessation of ovarian function before age 40. Clinical symptoms include menstrual disorders: amenorrhea/oligomenorrhea or symptoms of estrogen deficiency. This review aims to provide the most important summary of the immunophenotypic profile of premature ovarian failure syndrome, along with a review of the latest reports on the usefulness of inflammatory markers. The inflammatory microenvironment in POI applies to many levels. Concomitants of autoimmune ovarian inflammation and impaired cellular immune response may be a picture of impaired regulation in autoimmune ovarian disease. The serum concentration of pro-inflammatory cytokines, like IL-6, IL-8, IL-17, tumor necrosis factor α (TNF-α), and interferon-gamma (IFN-γ), tend to increase, whereas levels of the anti-inflammatory cytokine, IL-10, tend to decrease. In our review, we focus on whether the measured immunological parameters could help in the diagnosis and prognosis of the syndrome. Among the inflammatory markers, neutrophil-to-lymphocyte ratio (NLR) is noteworthy, as it is decreased in patients with POI. It is important to stress that besides case series, we need properly powered studies with randomization to answer which treatment is effective, and how to deal with concurrent autoimmunity. In this review, we emphasize the importance of the premature ovarian failure syndrome immunoprofile for a proper understanding of the complexity of this syndrome, potential diagnostic points, and therapeutic targets.

Effects of Cetrorelix on Ovary and Endometrium Prior to Anti-PD-L1 Antibody in Murine Model

BACKGROUND

Recent anti-cancer agents, immune checkpoint inhibitors (ICIs), have emerged as effective agents targeting the programmed cell death protein-1 (PD-1)/programmed death-ligand 1 (PD-L1) pathway. While the administration of gonadotropin-releasing hormone (GnRH) analogs before cytotoxic agents is known to preserve female reproductive organ function, the potential effects of ICIs and the protective impact of GnRH analogs on female reproductive organs, especially concerning ovarian reserve and endometrial receptivity, remain unknown. In this study, we attempted to elucidate the protective or regenerative effect on the female reproductive organ of cetrorelix prior to anti-PD-L1 antibody administration.

METHOD

Using a murine model, we examined the effects of Anti-PD-L1 antibody treatment on ovarian and uterine morphology, compared them with controls, and further assessed any potential protective effect of cetrorelix, a GnRH analog. Histological examinations and quantitative reverse transcription polymerase chain reaction were employed to study the morphological changes and associated gene expression patterns.

RESULTS

Anti-PD-L1 treatment led to a significant depletion of primordial/primary ovarian follicles and impaired decidualization in uterine stromal cells. However, while pretreatment with cetrorelix could restore normal decidualization patterns in the uterus, it did not significantly ameliorate ovarian follicular reductions. Gene expression analysis reflected these observations, particularly with marked changes in the expression of key genes like Prl and Igfbp1, pivotal in uterine decidualization.

CONCLUSION

Our study underscores the potential reproductive implications of cetrorelix treatment prior to Anti-PD-L1 therapy, shedding light on its short-term protective effects on the uterus. Further studies are necessary to understand long-term and clinical implications.

The constructive and destructive impact of autophagy on both genders' reproducibility, a comprehensive review

Reproduction is characterized by a series of massive renovations at molecular, cellular, and tissue levels. Recent studies have strongly tended to reveal the involvement of basic molecular pathways such as autophagy, a highly conserved eukaryotic cellular recycling, during reproductive processes. This review comprehensively describes the current knowledge, updated to September 2022, of autophagy contribution during reproductive processes in males including spermatogenesis, sperm motility and viability, and male sex hormones and females including germ cells and oocytes viability, ovulation, implantation, fertilization, and female sex hormones. Furthermore, the consequences of disruption in autophagic flux on the reproductive disorders including oligospermia, azoospermia, asthenozoospermia, teratozoospermia, globozoospermia, premature ovarian insufficiency, polycystic ovarian syndrome, endometriosis, and other disorders related to infertility are discussed as well.Abbreviations: AKT/protein kinase B: AKT serine/threonine kinase; AMPK: AMP-activated protein kinase; ATG: autophagy related; E2: estrogen; EDs: endocrine disruptors; ER: endoplasmic reticulum; FSH: follicle stimulating hormone; FOX: forkhead box; GCs: granulosa cells; HIF: hypoxia inducible factor; IVF: in vitro fertilization; IVM: in vitro maturation; LCs: Leydig cells; LDs: lipid droplets; LH: luteinizing hormone; LRWD1: leucine rich repeats and WD repeat domain containing 1; MAP1LC3: microtubule associated protein 1 light chain 3; MAPK: mitogen-activated protein kinase; MTOR: mechanistic target of rapamycin kinase; NFKB/NF-kB: nuclear factor kappa B; P4: progesterone; PCOS: polycystic ovarian syndrome; PDLIM1: PDZ and LIM domain 1; PI3K: phosphoinositide 3-kinase; PtdIns3P: phosphatidylinositol-3-phosphate; PtdIns3K: class III phosphatidylinositol 3-kinase; POI: premature ovarian insufficiency; ROS: reactive oxygen species; SCs: Sertoli cells; SQSTM1/p62: sequestosome 1; TSGA10: testis specific 10; TST: testosterone; VCP: vasolin containing protein.

TOPK inhibits TNF-α-induced granulosa cell apoptosis via regulation of SIRT1/p53

T-LAK cell originated protein kinase (TOPK) has been shown to regulate proliferation, invasion or migration of various cancer cells. However, the role of TOPK in follicle environments remains unknown. Here we reveal that TOPK inhibits TNF-α-induced human granulosa COV434 cell apoptosis. The expression of TOPK were increased in COV434 cells in response to TNF-α. TOPK inhibition also decreased TNF-α-induced SIRT1 expression but promoted TNF-α-induced p53 acetylation and expression of PUMA or NOXA. Accordingly, TOPK inhibition attenuated TNF-α-mediated SIRT1 transcriptional activity. In addition, SIRT1 inhibition augmented acetylation of p53 or expression of PUMA and NOXA in response to TNF-α, leading to COV434 cell apoptosis. We conclude that TOPK suppresses TNF-α-induced COV434 granulosa cell apoptosis via regulation of p53/SIRT1 axis, suggesting a potential role of TOPK in regulation of ovarian follicular development.

RNA sequencing-based transcriptome analysis of granulosa cells from follicular fluid: Genes involved in embryo quality during in vitro fertilization and embryo transfer

BACKGROUND

Granulosa cells play an important role in folliculogenesis, however, the role of RNA transcripts of granulosa cells in assessing embryo quality remains unclear. Therefore, we aims to investigate that RNA transcripts of granulosa cells be used to assess the probability of the embryonic developmental capacity.

METHODS

This prospective cohort study was attempted to figure out the probability of the embryonic developmental capacity using RNA sequencing of granulosa cells. Granulosa cells were collected from 48 samples in good-quality embryo group and 79 in only poor- quality embryo group from women undergoing in vitro fertilization and embryo transfer treatment. Three samples from each group were used for RNA sequencing.

RESULTS

226 differentially expressed genes (DEGs) were related to high developmental competence of embryos. Gene Ontology enrichment analysis indicated that these DEGs were primarily involved in biological processes, molecular functions, and cellular components. Additionally, pathway analysis revealed that these DEGs were enriched in 13 Kyoto Encyclopedia of Genes and Genomes pathways. Reverse transcription quantitative polymerase chain reaction verified the differential expression of the 13 selected DEGs. Among them,10 genes were differently expressed in the poor-quality embryo group compared to good-quality embryo group, including CSF1R, CTSH, SERPINA1, CYP27A1, ITGB2, IL1β, TNF, TAB1, BCL2A1, and CCL4.

CONCLUSIONS

RNA sequencing data provide the support or confute granulosa expressed genes as non-invasive biomarkers for identifying the embryonic developmental capacity.

Ovulation Induced by Intrauterine Seminal Plasma Increases Total Protein, PGE2, IL-8, and IL-1β in Uterine Fluid of Llamas (Lama glama)

The establishment of a state of immunotolerance in the female reproductive tract is important for embryo development, implantation and placentation. Llamas are induced ovulators and more than 98% of pregnancies occur in the left uterine horn. The objective of this study was to determine the uterine immune response of llamas in different stages of the reproductive cycle. Adult llamas (n = 20) were examined daily by transrectal ultrasonography to determine follicular growth and then randomly assigned to four groups: Follicular phase (n = 5); Luteal phase induced by an intramuscular administration of 50 ug of GnRH analogue (n = 5); Luteal phase induced by intrauterine infusion of seminal plasma (n = 5); and Luteal phase induced by mating (n = 5). Uterine fluid was collected separately from both uterine horns by non-surgical flushing to determine the presence of cells, total proteins and concentration of IL-1β, IL-6, IL-8, IFN γ, TNF-α and PGE2. Inflammatory cells were not observed in the uterine fluid and total protein pattern and inflammatory mediators did not differ between the left and the right horn amongst groups. Llamas treated with an intrauterine infusion of seminal plasma showed the highest concentration of total proteins, inflammatory cytokines PGE2, IL-8 and IL-1β in the uterine fluid. In conclusion, seminal plasma is made up of significant numbers of signaling molecules that are able to modify the uterine immune response in llamas.

New insights into mechanisms of berberine in alleviating reproductive disorders of polycystic ovary syndrome: Anti-inflammatory properties

Polycystic ovary syndrome (PCOS) is a complex reproductive disorder that seriously harms female reproductive health and decreases quality of life. Although spontaneous or assisted ovulation occurs, women with PCOS suffer from poor-quality oocytes and embryos and lower fertilization and final pregnancy rates. Therefore, it is urgent to identify new pathological mechanisms and discover the underlying therapeutic targets for reproductive disorders associated with PCOS. Berberine, one of the famous traditional Chinese medicines, has been shown to improve ovulation and live birth rates in women with PCOS. The effects of berberine on insulin resistance and abnormal glucose and lipid metabolism for restoring the reproductive health of women with PCOS are well recognized and have been widely studied, but much less attention has been given to its anti-inflammatory properties. Chronic low-grade inflammation is the unifying feature of PCOS and may contribute to reproductive disorders in PCOS. Berberine can modulate the inflammatory state of the ovaries and uterus in PCOS. The anti-inflammatory properties of berberine may provide new insight into the mechanisms by which berberine alleviates reproductive disorders associated with PCOS. Here, we summarized the most recent insights into the anti-inflammatory properties of berberine in PCOS reproductive disorders to inspire researchers to pursue new study directions involving berberine.

A review of autoimmunity and immune profiles in patients with primary ovarian insufficiency

Primary ovarian insufficiency (POI) is a complicated clinical syndrome characterized by progressive deterioration of ovarian function. Autoimmunity is one of the main pathogenic factors affecting approximately 10% to 55% of POI cases. This review mainly focuses on the role of autoimmunity in the pathophysiology of POI and the potential therapies for autoimmunity-related POI. This review concluded that various markers of ovarian reserve, principally anti-Müllerian hormone, could be negatively affected by autoimmune diseases. The presence of lymphocytic oophoritis, anti-ovarian autoantibodies, and concurrent autoimmune diseases, are the main characteristics of autoimmune POI. T lymphocytes play the most important role in the immune pathogenesis of POI, followed by disorders of other immune cells and the imbalance between pro-inflammatory and anti-inflammatory cytokines. A comprehensive understanding of immune characteristics of patients with autoimmune POI and the underlying mechanisms is essential for novel approaches of treatment and intervention for autoimmune POI.

MiR-34a-5p promotes autophagy and apoptosis of ovarian granulosa cells via the Hippo-YAP signaling pathway by targeting LEF1 in chicken

Follicular atresia is a natural physiological phenomenon in poultry reproduction. It is well known that follicular atresia is caused by both autophagy and apoptosis of granulosa cells. In current experiment, we evaluated the function of miR-34a-5p on autophagy and apoptosis in chicken follicular atresia. First, the follicular atresia model of chicken was successfully constructed by subcutaneous injection of tamoxifen (TMX), and found the expression of miR-34a-5p in the atresia follicles obviously increased. Then, we confirmed that miR-34a-5p accelerates autophagy and apoptosis of chicken granulose cells in vitro, and miR-34a-5p could induce apoptosis by mediating autophagy. Mechanistically, lymphoid enhancer binding factor 1 (LEF1) was deemed as a target gene for miR-34a-5p. On the contrary, LEF1 overexpression attenuated the autophagy and apoptosis of chicken granular cells. In addition, it was confirmed that the miR-34a-5p/LEF1 axis plays a regulatory role in chicken granulosa cells by mediating the Hippo-YAP signaling pathway. Taken together, this study demonstrated that miR-34a-5p contributes to autophagy and apoptosis of chicken follicular granulosa cells by targeting LEF1 to mediate the Hippo-YAP signaling pathway.

Mechanism of Mitochondrial Homeostasis Controlling Ovarian Physiology

Ovarian cells, including oocytes, granulosa/cumulus cells, theca cells, and stromal cells, contain abundant mitochondria, which play indispensable roles in the processes of ovarian follicle development. Ovarian function is closely controlled by mitochondrial proteostasis and mitostasis. While mitochondrial proteostasis and mitostasis are disturbed by several factors, leading to dysfunction of ovarian function and initiating the mitochondrial unfolded protein response (UPRmt) and mitophagy to maintain or recover ovarian function and mitochondrial function, clear interactions between the 2 pathways in the ovary have not been fully elucidated. Here, we comprehensively summarize the molecular networks or regulatory mechanisms behind further mitochondrial research in the ovary. This review provides novel insights into the interactions between the UPRmt and mitophagy in ovarian functions.

Checkpoint inhibitor immunotherapy diminishes oocyte number and quality in mice

Loss of fertility is a major concern for female reproductive-age cancer survivors, since a common side-effect of conventional cytotoxic cancer therapies is permanent damage to the ovary. While immunotherapies are increasingly becoming a standard of care for many cancers-including in the curative setting-their impacts on ovarian function and fertility are unknown. We evaluated the effect of immune checkpoint inhibitors blocking programmed cell death protein ligand 1 and cytotoxic T lymphocyte-associated antigen 4 on the ovary using tumor-bearing and tumor-free mouse models. We find that immune checkpoint inhibition increases immune cell infiltration and tumor necrosis factor-α expression within the ovary, diminishes the ovarian follicular reserve and impairs the ability of oocytes to mature and ovulate. These data demonstrate that immune checkpoint inhibitors have the potential to impair both immediate and future fertility, and studies in women should be prioritized. Additionally, fertility preservation should be strongly considered for women receiving these immunotherapies, and preventative strategies should be investigated in future studies.

Metformin abrogates pathological TNF-α-producing B cells through mTOR-dependent metabolic reprogramming in polycystic ovary syndrome

B cells contribute to the pathogenesis of polycystic ovary syndrome (PCOS). Clinically, metformin is used to treat PCOS, but it is unclear whether metformin exerts its therapeutic effect by regulating B cells. Here, we showed that the expression level of tumor necrosis factor-alpha (TNF-α) in peripheral blood B cells from PCOS patients was increased. Metformin used in vitro and in vivo was able to reduce the production of TNF-α in B cells from PCOS patients. Administration of metformin improved mouse PCOS phenotypes induced by dehydroepiandrosterone (DHEA) and also inhibited TNF-α expression in splenic B cells. Furthermore, metformin induced metabolic reprogramming of B cells in PCOS patients, including the alteration in mitochondrial morphology, the decrease in mitochondrial membrane potential, Reactive Oxygen Species (ROS) production and glucose uptake. In DHEA-induced mouse PCOS model, metformin altered metabolic intermediates in splenic B cells. Moreover, the inhibition of TNF-α expression and metabolic reprogramming in B cells of PCOS patients and mouse model by metformin were associated with decreased mTOR phosphorylation. Together, TNF-α-producing B cells are involved in the pathogenesis of PCOS, and metformin inhibits mTOR phosphorylation and affects metabolic reprogramming, thereby inhibiting TNF-α expression in B cells, which may be a new mechanism of metformin in the treatment of PCOS.

Suppressive Role of Lactoferrin in Overweight-Related Female Fertility Problems

The secretory glycoprotein lactoferrin (LF) is suggested to ameliorate overweight regardless of non-genetic or genetic mechanisms. Although maternal overweight represents a key predictor of offspring growth, the efficacy of LF on fertility problems in overweight and obese mothers remains unknown. To address this issue, we examined the effect of LF ingestion by analyzing overweight mice (Institute of Cancer Research (ICR) mice with high-fat diets; HF mice) and obese mice (leptin-deficient mice with type II diabetes; ob/ob mice). Plasma insulin, leptin, glucose, and cholesterol levels were measured, and thermal imaging and histological analysis were employed. The litter size of HF females was reduced due to miscarriage, which was reversed by LF ingestion. In addition, LF ingestion suppressed overweight prevalence in their offspring. The component analysis of the maternal blood demonstrated that glucose concentration in both HF females and their offspring was normalized by LF ingestion, which further standardized the concentration of insulin, but not leptin. LF ingestion was unable to reverse female infertility in ob/ob mice, although their obesity and uterine function were partially improved. Our results indicate that LF upregulates female fertility by reinforcing ovarian and uterine functions in females that are overweight due to caloric surplus.

Construction of Competing Endogenous RNA Networks Incorporating Transcription Factors to Reveal Differences in Granulosa Cells from Patients with Endometriosis

Purpose: This study aimed to reveal the molecular differences in granulosa cells (GCs) from patients with endometriosis (EM). Methods: RNA sequencing was performed on GCs from patients with EM-related infertility (n = 3) and controls (n = 3). Differentially expressed long noncoding RNAs [differentially expressed lncRNAs (DELs), |log2 FC|>4, false discovery rate (FDR) <0.05] and genes [differentially expressed genes (DEGs), |log2 FC|>1.4, FDR <0.05] in patients with EM-related infertility and controls were screened. Protein-protein interaction (PPI) networks of the DEGs were constructed. Then, mRNA-miRNA-lncRNA pairs based on DEGs and DELs were constructed by comprehensive bioinformatics analyses. In addition, overlapping genes identified from both the PPI and mRNA-miRNA-lncRNA pairs were selected. Finally, a competing endogenous RNA (ceRNA) network incorporating transcription factors (TFs) was constructed. Results: A total of 25,806 lncRNAs and 19,684 mRNAs were detected, and 7 DELs and 46 DEGs were identified. Five hub genes from the PPI network were also identified. A single overlapping gene, NR4A2, from both the PPI network and mRNA-miRNA-lncRNA pairs was identified. Finally, a ceRNA network incorporating TFs, including one mRNA (NR4A2), one miRNA (hsa-miR-217), three lncRNAs (XIST, MCM3AP-AS1, and C17orf51), and five TFs (SRF, POLR2A, NRF1, MNT, and TCF7L2), was successfully constructed. Conclusions: The proposed ceRNA network and the prediction of TFs in GCs from EM-related infertility revealed differences in GCs from patients with EM. Importantly, the novel TFs, lncRNAs, miRNAs, and mRNAs involved in the ceRNA network might provide new insights into the underlying molecular mechanisms of EM-related infertility.

Transcriptome Analysis of Porcine Granulosa Cells in Healthy and Atretic Follicles: Role of Steroidogenesis and Oxidative Stress

One of the main causes of female infertility is a deregulated antral follicular atresia, a process of which the underlying molecular mechanisms are largely unknown. Our objective was therefore to characterize the complex transcriptome changes in porcine granulosa cells of healthy antral (HA) and advanced antral atretic (AA) follicles, using ELISA and RNA-Seq followed by qRT-PCR and immunohistochemistry. Granulosa cell RNA-Seq data revealed 2160 differentially expressed genes, 1483 with higher and 677 with lower mRNA concentrations in AA follicles. Bioinformatic analysis showed that the upregulated genes in AA follicles were highly enriched in inflammation and apoptosis processes, while the downregulated transcripts were mainly highlighted in the steroid biosynthesis pathway and response to oxidative stress processes including antioxidant genes (e.g., GSTA1, GCLC, GCLM, IDH1, GPX8) involved in the glutathione metabolism pathway and other redox-related genes (e.g., RRM2B, NDUFS4). These observations were confirmed by RT-qPCR and immunohistochemistry. Additionally, the granulosa cells of AA follicles express significantly stronger 8-OHdG immunostaining, a marker of oxidative DNA damage, implicating that oxidative stress may participate in follicular atresia. We hypothesize that the decrease in anti-apoptotic factors and steroid hormones coincides with increased oxidative stress markers and the expression of pro-apoptotic factors, all contributing to antral follicular atresia.

Physiological and molecular aspects of heat-treated cultured granulosa cells of Egyptian buffalo (Bubalus bubalis)

The physiological and molecular responses of granulosa cells (GCs) from buffalo follicles were investigated when there were in vitro heat stress conditions imposed. The cultured GCs were heat-treated at 40.5 °C for 24, 48 or 72 h while GCs of the control group were not heat-treated (37 °C). There were no differences in viability between control and heat-treated groups. There was an upward trend in increase in E₂ secretion as the duration of heat stress advanced, being greater (P ≤ 0.05) for the GCs on which heat stress was imposed for 72 as compared with 24 h. In contrast, P₄ release was less (P ≤ 0.05) from GCs heat-treated for 48 h than those cultured for 24 h and GCs of the control group. The relative abundance of ATP5F1A and SOD2 mRNA transcripts was consistent throughout the period when there was imposing of heat stress to sustain mitochondrial function. The relative abundance of CPT2 transcript was less in heat-treated GCs than in GCs of the control group. There was a greater relative abundance of SREBP1 and TNF-α mRNA transcripts after 48 h of heat-treatment of GCs than GCs of the control group. In conclusion, the results from the current study indicate buffalo GCs cultured when there was imposing of heat stress maintained normal viability, steroidogenesis and transcriptional profile. The stability of antioxidant status and increased transcription of genes regulating cholesterol biosynthesis and stress resistance may be defense mechanisms of buffalo GCs against heat stress.

Prognostic role of follicular fluid tumor necrosis factor alpha in the risk of early ovarian hyperstimulation syndrome

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic condition characterized by capillary hyperpermeability which can be predicted by preovulatory ovarian responses such as number of follicles. A variety of cytokines are thought to be involved in pathophysiology of this syndrome.

METHODS

A prospective cohort study invloving sixty intracytoplasmic sperm injection (ICSI) patients. On the day of hCG injection, we explored the threshold of larger follicles ≥11 mm diameter with a count of ≥18 follicles for the high-risk moderate-to-severe OHSS and 13-18 follicles for the low-risk moderate-to-severe OHSS. Whereas larger follicles count of less than 13 were classified as normoresponders. Pooled follicular fluid (FF) samples of each patient were collected on the day of oocyte retrieval. Magnetic multiplex immunoassay was explored to measure the concentrations of some intrafollicular cytokines including: GM-CSF, INF-γ, TNF-α, IL-10, CXCL8/IL-8, IL-6, IL-5, IL-4, IL-2, and IL-1β. All sixty patients underwent controlled ovarian hyperstimulation (COH) with either GnRH agonist or antagonist protocols.

RESULTS

Intrafollicular TNF-α concentration was significantly different (p < 0.05) in the high-risk moderate-to-severe OHSS patients compared to low-risk moderate-to-severe OHSS patients and normoresponders. TNF-α in FF had a negative correlation with the chance of high-risk moderate-to-severe OHSS. The differences in the risk of OHSS between patients who received GnRH agonist or antagonist were not significant (p > 0.05).

CONCLUSIONS

In accordance to the negative correlation of TNF-α and high risk of early OHSS, we did not expect TNF-α to play a role in increasing vascular permeability in ovarian tissues. In addition, the risk of early moderate-to-severe OHSS was not affected by different GnRH superovulation protocols.

Pathophysiological roles of chronic low-grade inflammation mediators in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common hormonal imbalance disease in reproductive-aged women. Its basic characteristics are ovulatory dysfunction and ovarian overproduction of androgens that lead to severe symptoms such as insulin resistance, hirsutism, infertility, and acne. Notwithstanding the disease burden, its underlying mechanisms remain unknown, and no causal therapeutic exists. In recent years, further studies showed that inflammation processes are involved in ovulation and play a key role in ovarian follicular dynamics. Visceral adipose tissue can cause inflammatory response and maintenance of the inflammation state in adipocytes by augmented production of inflammatory cytokines, monocyte chemoattractant proteins, and recruitment of the immune cell. Therefore, the PCOS can be related to a low-grade inflammation state and inflammatory markers. Investigating the inflammatory processes and mediators that contribute to the commencement and development of PCOS can be a critical step for better understanding the pathophysiology of the disease and its treatment through inhibition or control of related pathways. In the present review, we discuss the pathophysiological roles of chronic low-grade inflammation mediators including inflammasome-related cytokines, interleukin-1β (IL-1β), and IL-18 in PCOS development.

Interleukin-1β and TNF-α systems in ovarian follicles and their roles during follicular development, oocyte maturation and ovulation

Tumour necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) are cytokines that are involved in the development, proliferation and apoptosis of ovarian follicular cells in domestic mammals. The expression of these cytokines in various follicular compartments, depending on the stage of follicle development, demonstrates their involvement in the control of primordial follicle growth up to the preovulatory stage. The mechanism of action of these factors depends on the presence of their receptors that transduce their biological actions. This review shows the expression sites of TNF-α, IL-1β and their receptors in ovarian follicles, and discusses the mechanism of action of these cytokines during follicle development, oocyte maturation and ovulation in domestic animals.

A prospective study of inflammatory biomarker levels and risk of early menopause

OBJECTIVE

Early menopause, the cessation of ovarian function before age 45, has consequences for fertility and cardiovascular health. Evidence from studies of women with autoimmune conditions and genetic studies supports a role for inflammation in early menopause, but the association of inflammatory markers and risk has not been directly evaluated.

METHODS

We assessed the relation of the soluble fraction of tumor necrosis factor alpha receptor 2 (sTNFR2), C-reactive protein, interleukin-6 (IL6) levels with incident early menopause among Nurses' Health Study II participants who provided a premenopausal blood sample in 1996 to 1999. Cases (n = 328) were women reporting natural menopause between blood collection and age 45.Controls (n = 492) included (1) 328 women with menopause after age 47, matched 1:1 with cases on age at blood collection and other factors; and (2) 164 additional women with menopause after age 45.

RESULTS

In multivariable models comparing cases and n = 492 controls, we observed a significant association of sTNFR2 levels and risk of early menopause (P = 0.002). Compared with women with the lowest sTNFR2 levels, odds ratios (95% CIs) for quartiles 2 to 4 were 0.60 (0.38-0.95), 0.93 (0.61-1.43), and 1.40 (0.93-2.11). Results further adjusting for antimüllerian hormone levels were similar in magnitude, as were results from sensitivity analyses of matched cases and controls (n = 328 pairs), nonsmokers, and leaner women. C-reactive protein and IL6 levels were unrelated to risk.

CONCLUSIONS

The observation of lower risk of early menopause among women with moderate sTNFR2 levels compared with women with lower and higher levels warrants further prospective study.

Lipopolysaccharide and tumor necrosis factor-alpha alter gene expression of oocytes and cumulus cells during bovine in vitro maturation

Communication between the oocyte and cumulus facilitates oocyte growth, cell cycle regulation, and metabolism. This communication is mediated by direct contact between oocytes and cumulus cells, and soluble secreted molecules. Secreted molecules involved in this process are known inflammatory mediators. Lipopolysaccharide (LPS) is detected in follicular fluid and is associated with reduced fertility, whereas accumulation of inflammatory mediators in follicular fluid, including tumor necrosis factor-α (TNF-α), is associated with female infertility. Maturation of oocytes in the presence of LPS or TNF-α reduces meiotic maturation and the capacity to develop to the blastocyst. Here we evaluated the abundance of 92 candidate genes involved immune function, epigenetic modifications, embryo development, oocyte secreted factors, apoptosis, cell cycle, and cell signaling in bovine cumulus cells or zona-free oocytes after exposure to LPS or TNF-α during in vitro maturation. We hypothesize that LPS or TNF-α will alter the abundance of transcripts in oocytes and cumulus cell in a cell type dependent manner. Exposure to LPS altered abundance of 31 transcripts in oocytes (including ACVR1V, BMP15, DNMT3A) and 12 transcripts in cumulus cells (including AREG, FGF4, PIK3IP1). Exposure to TNF-α altered 1 transcript in oocytes (IGF2) and 4 transcripts in cumulus cells (GJA1, PLD2, PTGER4, STAT1). Cumulus expansion was reduced after exposure to LPS or TNF-α. Exposing COCs to LPS had a marked effect on expression of targeted transcripts in oocytes. We propose that altered oocyte transcript abundance is associated with reduced meiotic maturation and embryo development observed in oocytes cultured in LPS or TNF-α.

Polycystic ovary syndrome: possible involvement of androgen-induced, chemerin-mediated ovarian recruitment of monocytes/macrophages

Polycystic ovary syndrome (PCOS) is a continuum of endocrine and reproductive disorders characterized by hyperandrogenism, antral follicle growth arrest, and chronic inflammation. Macrophages play key role in inflammation, and the balance between M1 (inflammatory) and M2 (anti-inflammatory) macrophages determines physiological/pathological outcomes. Here, we investigated if hyperandrogenism increases ovarian chemerin altering the balance of M1 and M2 macrophages and the granulosa cell death. Ovarian chemerin was upregulated by 5α-dihydrotestosterone (DHT) in lean and overweight rats; while increased serum chemerin levels were only evident in overweight rats, suggesting that the serum chemerin may be reflective of a systemic response and associated with obesity, whereas increased ovarian chemerin expression is a localized response independent of the metabolic status. DHT altered follicle dynamics while increased the M1: M2 macrophages ratio in antral and pre-ovulatory follicles. While ovarian M1 macrophages expressing chemokine-like receptor 1 (CMKLR1) were increased, CMKLR1+ monocytes, which migrated toward chemerin-rich environment, were markedly decreased after 15 days of DHT. Androgen-induced granulosa cell apoptosis was dependent on the presence of macrophages. In humans, chemerin levels in follicular fluid, but not in serum, were higher in lean PCOS patients compared to BMI-matched controls and were associated with increased M1: M2 ratio. Our results support the concept that in PCOS, hyperandrogenemia increases chemerin expression while promotes CMKLR1+ monocytes recruitment and deregulates the immunological niche of ovaries. This study established a new immunological perspective in PCOS at the ovarian level. Hyperandrogenism is associated with upregulation of chemerin and macrophage unbalance in the ovaries.

DNA methylome profiling of granulosa cells reveals altered methylation in genes regulating vital ovarian functions in polycystic ovary syndrome

Background

Women with polycystic ovary syndrome (PCOS) manifest a host of ovarian defects like impaired folliculogenesis, anovulation, and poor oocyte quality, which grossly affect their reproductive health. Addressing the putative epigenetic anomalies that tightly regulate these events is of foremost importance in this disorder. We therefore aimed to carry out DNA methylome profiling of cumulus granulosa cells and assess the methylation and transcript expression profiles of a few differentially methylated genes contributing to ovarian defects in PCOS. A total of 20 controls and 20 women with PCOS were selected from a larger cohort of women undergoing IVF, after carefully screening their sera and follicular fluids for hormonal and biochemical parameters. DNA extracted from cumulus granulosa cells of three women each, from control and PCOS groups was subjected to high-throughput, next generation bisulfite sequencing, using the Illumina HiSeq 2500® platform. Remaining samples were used for the validation of methylation status of some identified genes by pyrosequencing, and the transcript expression profiles of these genes were assessed by quantitative real-time PCR.

Results

In all, 6486 CpG sites representing 3840 genes associated with Wnt signaling, G protein receptor, endothelin/integrin signaling, angiogenesis, chemokine/cytokine-mediated inflammation, etc., showed differential methylation in PCOS. Hypomethylation was noted in 2977 CpGs representing 2063 genes while 2509 CpGs within 1777 genes showed hypermethylation. Methylation differences were also noted in noncoding RNAs regulating several ovarian functions that are dysregulated in PCOS. Few differentially methylated genes such as aldo-keto reductase family 1 member C3, calcium-sensing receptor, resistin, mastermind-like domain 1, growth hormone-releasing hormone receptor and tumor necrosis factor, which predominantly contribute to hyperandrogenism, premature luteolysis, and oocyte development defects, were explored as novel epigenetic candidates in mediating ovarian dysfunction. Methylation profiles of these genes matched with our NGS findings, and their transcript expression patterns correlated with the gene hypo- or hypermethylation status.

Conclusion

Our findings suggest that the epigenetic dysregulation of genes involved in important processes associated with follicular development may contribute to ovarian defects observed in women with PCOS.

Electronic supplementary material

The online version of this article (10.1186/s13148-019-0657-6) contains supplementary material, which is available to authorized users.

Impact of vitrification on granulosa cell survival and gene expression

INTRODUCTION

Cryopreservation of ovarian tissue is an essential step in Ovarian Tissue Banking. In order to prevent the formation of ice crystals, typically the tissue is slowly frozen using a cryoprotectant. As an alternative the method of ultra-fast freezing by vitrification becomes more attention for freezing ovarian tissue because it has successfully been used for oocytes, embryos and sperm. However the impact of vitrification on granulosa cells, which are an essential part of ovarian tissue is uncertain.

AIM

In this study, we have therefore analysed the influence of vitrification on the survival rates of granulosa cells, the impact of DMSO or ethylenglycol containing vitrification protocols and investigated to what extent the gene expression of apoptosis- and temperature-sensitive genes changes.

MATERIAL AND METHODS

We used the human granulosa cell line KGN as a model for human granulosa cells and determined the survival rate and cell cycle stages by FACS analyses. The change in gene expression was determined by quantitative PCR analyses.

RESULTS

Our results show that vitrification is possible in granulosa cells but it reduces cell viability and leads to fluctuations in the cell cycle. The DMSO containing protocol results in a lower amount of dead cells than the ethylenglycol containing protocol. Gene expression analysis reveals that TNF-alpha expression is strongly increased after vitrification, while other apoptosis or temperature-related genes seem to stay unaffected.

CONCLUSION

We conclude that vitrification influences the viability of human granulosa cells. Furthermore, our results suggest that this could be mediated by a change in TNF-alpha gene expression.

Expression of atresia biomarkers in granulosa cells after ovarian stimulation in heifers

The use of younger gamete donors in dairy cattle genetic selection programs significantly accelerates genetic gains by decreasing the interval between generations. Ovarian stimulation (OS) and the practice of follicle-stimulating hormone (FSH) withdrawal, also known as coasting, are intensively used in pre-pubertal heifers without detrimental effects on subsequent reproductive performance but generally with lower embryo yields. However, recent data from embryo transfer programs showed similar embryo yields in younger and sexually mature animals but with a significant difference in the coasting period. The aim of the present study was to identify a set of granulosa cell biomarkers capable of distinguishing optimal follicle differentiation from late differentiation and atresia in order to assess the differences in coasting dynamics between pre- and post-pubertal donors. We integrated transcriptomic data sets from a public depository and used vote counting meta-analysis in order to elucidate the molecular changes occurring in granulosa cells during late follicle differentiation and atresia. The meta-analysis revealed the gene expression associated with follicle demise, and most importantly, identified potential biomarkers of that status in bovine granulosa cells. The comparison of the expression of six biomarkers between pre- and post-pubertal donors revealed that younger donors had more signs of atresia after the same period of coasting. We found different follicular dynamics following coasting in younger donors. It is possible that younger donors are less capable to sustain follicular survival most likely due to insufficient luteinizing hormone signaling. In summary, the pre-pubertal status influences follicular dynamics and reduces the oocyte developmental competence curve following OS and FSH withdrawal in heifers.

Cytosolic DNA sensor-initiated innate immune responses in mouse ovarian granulosa cells

Viral infections of the ovary may perturb ovarian functions. However, the mechanisms underlying innate immune responses in the ovary are poorly understood. The present study demonstrates that cytosolic viral DNA sensor signaling initiates the innate immune response in mouse ovarian granulosa cells and affects endocrine function. The cytosolic DNA sensors p204 and cGAS and their common signaling adaptor stimulator of interferon (IFN) genes (STING) were constitutively expressed in granulosa cells. Transfection with VACV70, a synthetic vaccinia virus (VACV) DNA analog, induced the expression of type I interferons (IFNA/B) and major inflammatory cytokines (TNFA and IL6) through IRF3 and NF-κB activation respectively. Moreover, several IFN-inducible antiviral proteins, including 2',5'-oligoadenylate synthetase, IFN-stimulating gene 15 and Mx GTPase 1, were also induced by VACV70 transfection. The innate immune responses in granulosa cells were significantly reduced by the transfection of specific small-interfering RNAs targeting p204, cGas or Sting Notably, the VACV70-triggered innate immune responses affected steroidogenesis in vivo and in vitro The data presented in this study describe the mechanism underlying ovarian immune responses to viral infection.

MicroRNA let-7g regulates mouse granulosa cell autophagy by targeting insulin-like growth factor 1 receptor

As an important type of somatic cell, granulosa cells play a major role in deciding the fate of follicles. Therefore, analyses of granulosa cell apoptosis and follicular atresia have become hotspots of animal research. Autophagy is a cellular catabolic mechanism that protects cells from stress conditions, including starvation, hypoxia, and accumulation of misfolded proteins. However, the relationship between autophagy and apoptosis in granulosa cells is not well known. Here, we demonstrate that let-7g regulates the mouse granulosa cell autophagy signaling pathway by inhibiting insulin-like growth factor 1 receptor expression and affecting the phosphorylation of protein kinase B/mammalian target of rapamycin. Small interference-mediated knockdown of insulin-like growth factor 1 receptor significantly promoted autophagy signaling of mouse granulosa cells. In contrast, overexpression of insulin-like growth factor 1 receptor in mouse granulosa cells attenuated autophagy activity in the presence of let-7g. In addition, overexpression of let-7g increased the apoptosis rate, as indicated by an increased number of terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling-positive cells. Finally, 3-methyladenine as well as the lysosomal enzyme inhibitor chloroquine partially blocked apoptosis. In summary, this study demonstrates that let-7g regulates autophagy in mouse granulosa cells by targeting insulin-like growth factor 1 receptor and downregulating protein kinase B/mammalian target of rapamycin signaling, and that mouse granulosa cell autophagy induced by let-7g participates in apoptosis.

Relationship between bcl-2, bax, beclin-1, and cathepsin-D proteins during postovulatory follicular regression in fish ovary

In fish ovaries, postovulatory follicles (POFs) are key biomarkers of breeding and provide an interesting model for studying the relationship between autophagy and apoptosis. In this study, we investigated the immunohistochemical expression of autophagic and apoptotic proteins to improve the knowledge on the mechanisms regulating ovarian remodeling after spawning. Females from three neotropical fish species kept in captivity were submitted to hormonal induction. After ova stripping, ovarian sections were sampled daily until 5 days postspawning (dps). Similar events of POF regression were detected by histology, terminal transferase-mediated dUTP nick-end labeling (TUNEL), and electron microscopy in the three species: follicular cells hypertrophy, progressive disintegration of the basement membrane, gradual closing of the follicular lumen, theca thickening, and formation of large autophagic vacuoles preceding apoptosis of the follicular cells. Autophagic and apoptotic proteins were assessed by immunohistochemistry. Morphometric analysis of the immunolabeling revealed a more intense reaction for bcl-2 and beclin-1 (BECN1) in POFs at 0 to 1 dps and for bax at 2 to 3 dps (P < 0.001), the later period being the peak of apoptosis of the follicular cells. The immunostaining for cathepsin-D was more elevated until 2 to 3 dps and decreased significantly at 4 to 5 dps, when the POFs were in late stage of regression. Double labeling for BECN1 and caspase-3 indicated a shift in the relationship between autophagy and apoptosis at 2 to 3 dps, a critical period in determining the fate of follicular cells in POFs. Together, these results indicate that the bcl-2 family, BECN1, and cathepsin-D can be involved in the regulation of ovarian remodeling in teleost fish.