Mitochondrial Protein Turnover Is Critical for Granulosa Cell Proliferation and Differentiation in Antral Follicles

ZDHHC17 participates in the pathogenesis of polycystic ovary syndrome by affecting androgen conversion to estrogen in granulosa cells

Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder affecting women of reproductive age and is a significant cause of female subfertility. Our previous research demonstrated that the abnormal palmitoylation of heat shock protein-90α (HSP90α) plays a role in the development of PCOS. However, the palmitoyl acyltransferases in HSP90α palmitoylation remain poorly understood. Herein, we identified ZDHHC17 as a major palmitoyl acyltransferase for HSP90α palmitoylation in granulosa cells. ZDHHC17 protein expression was diminished under excess androgen conditions in vitro and in vivo. Consistently, ovarian ZDHHC17 expression was found to be attenuated in patients with PCOS. ZDHHC17 depletion decreased HSP90α palmitoylation levels and hampered the conversion of androgen to estrogen via CYP19A1. Furthermore, ZDHHC17-mediated regulation of CYP19A1 expression was dependent on HSP90α palmitoylation. Our findings reveal that the regulatory role of HSP90α palmitoylation by ZDHHC17 is critical in PCOS pathophysiology and provide insights into the role of ZDHHC17 in reproductive endocrinology.

Increased IGFBP2 Levels by Placenta-Derived Mesenchymal Stem Cells Enhance Glucose Metabolism in a TAA-Injured Rat Model via AMPK Signaling Pathway

The insulin resistance caused by impaired glucose metabolism induces ovarian dysfunction due to the central importance of glucose as a source of energy. However, the research on glucose metabolism in the ovaries is still lacking. The objectives of this study were to analyze the effect of PD-MSCs on glucose metabolism through IGFBP2-AMPK signaling and to investigate the correlation between glucose metabolism and ovarian function. Thioacetamide (TAA) was used to construct a rat injury model. PD-MSCs were transplanted into the tail vein (2 × 106) 8 weeks after the experiment started. The expression of the IGFBP2 gene and glucose metabolism factors (e.g., AMPK, GLUT4) was significantly increased in the PD-MSC group compared to the nontransplantation (NTx) group (* p < 0.05). The levels of follicular development markers and the sex hormones AMH, FSH, and E2 were also higher than those in the TAA group. Using ex vivo cocultivation, the mRNA and protein expression of IGFBP2, AMPK, and GLUT4 were significantly increased in the cocultivation with the PD-MSCs group and the recombinant protein-treated group (* p < 0.05). These findings suggest that the increased IGFBP2 levels by PD-MSCs play an important role in glucose metabolism and ovarian function through the IGFBP2-AMPK signaling pathway.

Quantum Sensing of Free Radicals in Primary Human Granulosa Cells with Nanoscale Resolution

Cumulus granulosa cells (cGCs) and mural granulosa cells (mGCs), although derived from the same precursors, are anatomically and functionally heterogeneous. They are critical for female fertility by supporting oocyte competence and follicular development. There are various techniques used to investigate the role of free radicals in mGCs and cCGs. Yet, temporospatial resolution remains a challenge. We used a quantum sensing approach to study free radical generation at nanoscale in cGCs and mGCs isolated from women undergoing oocyte retrieval during in vitro fertilization (IVF). Cells were incubated with bare fluorescent nanodiamonds (FNDs) or mitochondria targeted FNDs to detect free radicals in the cytoplasm and mitochondria. After inducing oxidative stress with menadione, we continued to detect free radical generation for 30 min. We observed an increase in free radical generation in cGCs and mGCs from 10 min on. Although cytoplasmic and mitochondrial free radical levels are indistinguishable in the physiological state in both cGCs and mGCs, the free radical changes measured in mitochondria were significantly larger in both cell types, suggesting mitochondria are sites of free radical generation. Furthermore, we observed later occurrence and a smaller percentage of cytoplasmic free radical change in cGCs, indicating that cGCs may be more resistant to oxidative stress.

The Intergeneration Long-Lasting Consequences of Pre-Conceptional Exposure to Sofosbuvir on the Ovarian Tissues of F1 Offspring: Experimental Study on Rats

Sofosbuvir (SOF), a nucleos(t)ide polymerase inhibitor, has been used during the past decade for mass treatment of viral hepatitis C in endemic countries like Egypt, increasing the exposure of women at childbearing age to SOF. This study investigated the long-lasting consequences of the pre-conceptional exposure of young female rats to SOF on the ovarian tissues of F1 offspring and explored the possible molecular mechanisms of these intergenerational effects at various levels. The study was conducted on young female rats that were divided into control group and SOF-exposed group at a dose of 4 mg/kg/day for three months. After that, pregnancy was induced in both groups by mating with healthy male rats. After delivery, the female neonates were followed for 4 months, and the ovarian tissues were collected to assess the studied parameters. Pre-conceptional exposure to SOF affected the ovarian functions of F1 offspring through modulation of estrogen receptors, ovarian Kiss1 and its receptor, increased lipid peroxidation marker, DNA oxidation marker, and redox-sensitive nuclear factor kappa B, and decreased nuclear erythroid-2-related factor 2, mitochondrial function, and biogenesis. SOF affected the ovarian function of the F1 offspring by inducing oxidative stress and inflammation, leading to the modulation of mitochondrial functions and biogenesis.

The temporal and spatial signature of microglial transcriptome in neuropathic pain

Microglial activation following peripheral nerve injury is crucial for neuropathic pain (NP) development; however, studies on time-specific and spatial characteristics of microglial transcriptome are scarce. Firstly, we comparatively analysed microglial transcriptome of different brain regions and multiple timepoints after nerve injury by analysing the gene expression profile of GSE180627 and GSE117320. Then, we performed a mechanical pain hypersensitivity test on 12 rat neuropathic pain models using von Frey fibres at various timepoints after nerve injury. To further explore the key gene clusters closely related to the neuropathic pain phenotype, we conducted a weighted gene co-expression network analysis (WGCNA) on the GSE60670 gene expression profile. Lastly, we performed a single-cell sequencing analysis on GSE162807 for identifying microglia subpopulations. We found that the trend of microglia's transcriptome changes after nerve injury was that mRNA expression changes mainly occur early after injury, which is also consistent with phenotypic changes (NP progression). We also revealed that in addition to spatial specificity, microglia are also temporally specific in NP progression following nerve injury. The WGCNA findings revealed that the functional analysis of the key module genes emphasized the endoplasmic reticulum's (ER's) crucial role in NP. In our single-cell sequencing analysis, microglia were clustered into 18 cell subsets, of which we identified specific subsets of two timepoints (D3/D7) post-injury. Our study further revealed the temporal and spatial gene expression specificity of microglia in neuropathic pain. These results contribute to our comprehensive understanding of the pathogenic mechanism of microglia in neuropathic pain.

Mitoguardin2 Is Associated With Hyperandrogenism and Regulates Steroidogenesis in Human Ovarian Granulosa Cells

Polycystic ovary syndrome (PCOS) is an endocrinopathy characterized by hyperandrogenism, anovulation, and polycystic ovaries, in which hyperandrogenism manifests by excess androgen and other steroid hormone abnormalities. Mitochondrial fusion is essential in steroidogenesis, while the role of mitochondrial fusion in granulosa cells of hyperandrogenic PCOS patients remains unclear. In this study, mRNA expression of mitochondrial fusion genes mitoguardin1, -2 (MIGA 1, -2) was significantly increased in granulosa cells of hyperandrogenic PCOS but not PCOS with normal androgen levels, their mRNA expression positively correlated with testosterone levels. Dihydrotestosterone (DHT) treatment in mice led to high expression of MIGA2 in granulosa cells of ovulating follicles. Testosterone or forskolin/ phorbol 12-myristate 13-acetate treatments increased expression of MIGA2 and the steroidogenic acute regulatory protein (StAR) in KGN cells. MIGA2 interacted with StAR and induced StAR localization on mitochondria. Furthermore, MIGA2 overexpression significantly increased cAMP-activated protein kinase A (PKA) and phosphorylation of AMP-activated protein kinase (pAMPK) at T172 but inhibited StAR protein expression. However, MIGA2 overexpression increased CYP11A1, HSD3B2, and CYP19A1 mRNA expression. As a result, MIGA2 overexpression decreased progesterone but increased estradiol synthesis. Besides the androgen receptor, testosterone or DHT might also regulate MIGA2 and pAMPK (T172) through LH/choriogonadotropin receptor-mediated PKA signaling. Taken together, these findings indicate that testosterone regulates MIGA2 via PKA/AMP-activated protein kinase signaling in ovarian granulosa cells. It is suggested mitochondrial fusion in ovarian granulosa cells is associated with hyperandrogenism and potentially leads to abnormal steroidogenesis in PCOS.

Granulosa cells from immature follicles exhibit restricted glycolysis and reduced energy production: a dominant problem in polycystic ovary syndrome

PURPOSE

We hypothesized that immature oocytes are associated with impaired energy production in surrounding granulosa cells (GCs) in polycystic ovary syndrome (PCOS). Thus, this study investigated mitochondrial function, determined expression of glycolytic regulatory enzymes, and measured ATP levels in GCs of PCOS patients.

METHODS

GCs were isolated from forty-five PCOS patients and 45 control women. Intracellular concentration of reactive oxygen species (ROS), mitochondrial membrane potential (Δψm), the rate of glycolysis, total antioxidant capacity (TAC), activities of catalase (CAT) and superoxide dismutase (SOD), and ATP level were measured in GCs. The gene expression and protein levels of glycolytic enzymes (hexokinase, muscular phosphofructokinase, platelet derived phosphofructokinase, and muscular pyruvate kinase) were determined. Association of GC energy level with oocyte maturation was further validated by measuring glycolysis rate and ATP level in GCs isolated from mature and immature follicles from new set of fifteen PCOS patients and 15 controls.

RESULTS

PCOS patients showed higher ROS level, decreased TAC, reduced CAT and SOD activities, and lower Δψm together with reduced expression of key glycolytic enzymes. ATP concentration and biochemical pregnancy were lower in PCOS compared with control group. ATP levels were found to be significantly correlated with ROS and Δψm (r = - 0.624 and r = 0.487, respectively). GCs isolated from immature follicles had significantly lower ATP levels and rate of glycolysis compared with the GCs separated from mature follicles in both PCOS patients and control.

CONCLUSION

Declined energy due to the mitochondrial dysfunction and restrained glycolysis in GCs is associated with the immature oocytes and lower biochemical pregnancy in PCOS.

Yangjing Zhongyu decoction facilitates mitochondrial activity, estrogenesis, and energy metabolism in H2O2-induced human granulosa cell line KGN

ETHNOPHARMACOLOGICAL RELEVANT

Yangjing Zhongyu decoction (YJZYD) is a recipe from a Chinese classic medical work and has been empirically used in female infertility for hundreds of years, but the mechanisms of YJZYD on facilitating ovarian granulosa cells remain unfold.

AIM OF THE RESEARCH

The purpose of the study is to determine the rewarding effects of YJZYD on H₂O₂-induced KGN cells, involving mitochondrial activity, estradiol biosynthesis, and energy metabolism.

MATERIALS AND METHODS

The ingredients of YJZYD were investigated by UPLC-ESI-MS/MS analysis. The effects of YJZYD and H₂O₂ on cell viability were determined by CCK-8. Intracellular ROS were assessed by DCFH-DA. Intracellular Ca²⁺ was detected using Fura-4 AM. Mitochondrial membrane potential (MMP) was measured by JC-1. The production of energy was assessed by ATP. Apoptosis rate was analyzed by Annexin V-FITC/PI. Western blotting was used to evaluate the expression of proteins related to energy metabolism, apoptosis, mitochondrial mitophagy, and estrogen biosynthesis. E₂ levels were measured by ELISA.

RESULTS

121 compounds were identified in YJZYD by UPLC-ESI-MS/MS analysis. YJZYD could enhance mitochondrial activity by suppressing intracellular ROS and Ca²⁺, and increasing MMP and ATP content. YJZYD stimulated the expression of anti-apoptosis protein Bcl-2 and lowered the early apoptosis rate and the expression of Bax. Besides, YJZYD rescued E₂ secretion and improved the expression of FSHR, CYP19A1, and the ratio of p-CREB/CREB. In addition, YJZYD weakened H₂O₂-induced mitophagy by compromising the expression of PINK1, Parkin, Beclin1 and P62. Moreover, YJZYD strengthened energy metabolism by increasing ATP generation and the expression of SIRT1, PGC1α, NRF1, and COX IV. The combination of YJZYD and autophagy inhibitor had a stronger protective effect on energy metabolism.

CONCLUSION

This study evaluated the protective effects of YJZYD on H₂O₂-induced KGN cells. YJZYD could enhance mitochondrial activity, E₂ biosynthesis, and energy metabolism. These results strongly indicated that YJZYD might play a role in preserving ovarian granulosa cells and female fecundity.

Decrease in ovarian reserve through the inhibition of SIRT1-mediated oxidative phosphorylation

OBJECTIVE

To establish an oxidative stress-induced model of premature ovarian insufficiency (POI) and to explore the effect of SIRT1 and mitochondrial oxidative phosphorylation on the ovarian reserve.

METHODS

Mice were treated with intraperitoneal injections of 3-nitropropionic acid (3-NPA) at different doses and for different time periods to induce a model of POI. Subsequently, the efficiency of each regimen was evaluated. The expression of SIRT1 in ovarian tissue was examined. Then, SIRT1 was knocked down in human luteinized granulosa cells (GCs), and its function and related receptor and gene expression were examined. Finally, a SIRT1 antagonist and agonist were used to explore the effects of SIRT1 on ovarian function in vivo and on the change in mitochondrial oxidative phosphorylation complexes (OXPHOS).

RESULTS

Decreases in ovarian reserve were successfully induced through the intraperitoneal injection of 40 mg/kg 3-NPA for 3 weeks, and SIRT1 was down-regulated in the model group. The knockdown of SIRT1 impaired the estrogen synthesis capacity of human GCs and decreased the expression of related genes. 3-NPA and SIRT1 antagonist Ex-527 decreased ovarian function and inhibited OXPHOS. In contrast, the SIRT1 agonist resveratrol promoted the recovery of ovarian function in the model group and improved OXPHOS. Additionally, P53, CASPASE 3, and BAX were down-regulated and BCL2 was up-regulated in the 3-NPA and Ex-527 groups; opposite trends were observed after resveratrol treatment.

CONCLUSIONS

The intraperitoneal injection of 40 mg/kg 3-NPA for 3 weeks could effectively induce POI. The increase in oxidative stress inhibited SRIT1 and mitochondrial oxidative phosphorylation, inducing follicular apoptosis.

Role of the mtDNA Mutations and Mitophagy in Inflammaging

Ageing is an unavoidable multi-factorial process, characterised by a gradual decrease in physiological functionality and increasing vulnerability of the organism to environmental factors and pathogens, ending, eventually, in death. One of the most elaborated ageing theories implies a direct connection between ROS-mediated mtDNA damage and mutations. In this review, we focus on the role of mitochondrial metabolism, mitochondria generated ROS, mitochondrial dynamics and mitophagy in normal ageing and pathological conditions, such as inflammation. Also, a chronic form of inflammation, which could change the long-term status of the immune system in an age-dependent way, is discussed. Finally, the role of inflammaging in the most common neurodegenerative diseases, such as Alzheimer’s and Parkinson’s, is also discussed.

Follicular fluid steroid and gonadotropic hormone levels and mitochondrial function from exosomes predict embryonic development

PURPOSE

Human follicular fluid (FF) is a complex biological fluid that contributes to the micro-environment of oocyte development. The aim of this study was to evaluate the role of steroid and gonadotropic hormones levels and mitochondrial function in embryo development during in vitro fertilization cycles.

METHODS

This was a cohort study of 138 women receiving IVF/ICSI, including 136 FF samples from 109 infertile women. FF steroid and gonadotropic hormones levels were tested by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and immunoassays. The mRNA expression levels of mitochondrial electron transport chain (ETC) complex genes from FF exosomes were detected by qPCR.

RESULTS

Analysis of these individual FF concentrations revealed that LH and FSH concentrations were higher in follicles in which the oocyte developed into a top quality (TQ) blastocyst (LH: 9.44 ± 2.32mIU/ml, FSH: 9.32 ± 1.01mIU/ml) than those in which there was a failure of fertilization (LH: 5.30 ± 0.84mIU/ml, FSH: 6.91 ± 0.62mIU/ml). In contrast, follicular cortisone concentrations were lower for oocytes that resulted in a TQ blastocyst (12.20 ± 0.82mIU/ml). The receiver operating characteristic analysis showed that FF LH and FSH levels predicted TQ blastocyst with excellent AUC value of 0.711 and 0.747. Mitochondrial ETC complex I and III mRNA levels were increased in the FF exosomes of TQ blastocyst. Correlation analysis showed that mRNA levels of ETC complex I was positively correlated with LH and FSH levels in FF.

CONCLUSION

The levels of FF steroid and gonadotropic hormones from single follicle can predetermine subsequent embryo development to some extent. Furthermore, impaired exosome mitochondrial dysfunction is a potiential event that causes hormone change in embryo development.

Towards Personalized Antioxidant Use in Female Infertility: Need for More Molecular and Clinical Studies

Treatment with antioxidants is increasingly used to slow down aging processes in different organs of the human body, including those implicated in female fertility. There is a plethora of different natural, synthetic or semi-synthetic medicines available on the market; most of them can be purchased without medical prescription. Even though the use of antioxidants, even under conditions of auto-medication, was shown to improve many functions related to female infertility related to oxidative stress, the lack of medical control and supervision can lead to an overmedication resulting in an opposite extreme, reductive stress, which can be counterproductive with regard to reproductive function and produce various adverse health effects in general. This paper reviews the current knowledge relative to the effects of different antioxidants on female reproductive function. The persisting gaps in this knowledge are also highlighted, and the need for medical supervision and personalization of antioxidant prescription is underscored.

Large-scale DNA demethylation occurs in proliferating ovarian granulosa cells during mouse follicular development

During ovarian follicular development, granulosa cells proliferate and progressively differentiate to support oocyte maturation and ovulation. To determine the underlying links between proliferation and differentiation in granulosa cells, we determined changes in 1) the expression of genes regulating DNA methylation and 2) DNA methylation patterns, histone acetylation levels and genomic DNA structure. In response to equine chorionic gonadotropin (eCG), granulosa cell proliferation increased, DNA methyltransferase (DNMT1) significantly decreased and Tet methylcytosine dioxygenase 2 (TET2) significantly increased in S-phase granulosa cells. Comprehensive MeDIP-seq analyses documented that eCG treatment decreased methylation of promoter regions in approximately 40% of the genes in granulosa cells. The expression of specific demethylated genes was significantly increased in association with specific histone modifications and changes in DNA structure. These epigenetic processes were suppressed by a cell cycle inhibitor. Based on these results, we propose that the timing of sequential epigenetic events is essential for progressive, stepwise changes in granulosa cell differentiation.

MiR-145 regulates steroidogenesis in mouse primary granulosa cells through targeting Crkl

AIMS

It has been demonstrated that miR-145 is expressed in primordial follicles and modulates the initiation of primordial follicle development. We aimed to explore the function of miR-145 in mouse granulosa cells (mGCs).

MATERIALS AND METHODS

The proliferation and differentiation of GCs were examined via MTT, EDU assay, QRT-PCR, ELISA and electron microscope analysis. The target of miR-145 was determined by bioinformatics analysis and luciferase reporter assay and the molecular mechanisms were examined via western blot and quantitative Real-Time RT-PCR.

KEY FINDINGS

We proved that down-regulation of miR-145 could inhibit GCs proliferation and differentiation. In addition, we provided evidence that Crkl was the target gene of miR-145. The miR-145 antagomir caused an increase in Crkl expression and activation of the JNK/p38 MAPK pathway. Overexpression of Crkl with pEGFP-N1-Crkl vector inhibited GCs differentiation and progesterone synthesis as well as activation of the JNK/p38 MAPK pathway.

SIGNIFICANCE

Our study shows that miR-145 targets Crkl and through the JNK/p38 MAPK signaling pathway promotes the GCs proliferation, differentiation, and steroidogenesis. MiR-145 may play an important role in the ovarian physiology and pathology.

A mixture of persistent organic pollutants detected in human follicular fluid increases progesterone secretion and mitochondrial activity in human granulosa HGrC1 cells

Disruption of granulosa cells (GCs), the main functional cells in the ovary, is associated with impaired female fertility. Epidemiological studies demonstrated that women have detectable levels of organic pollutants (e.g., perfluorooctanoate, perfluorooctane sulfonate, 2,2-dichlorodiphenyldichloroethylene, polychlorinated biphenyl 153, and hexachlorobenzene) in their follicular fluid (FF), and thus these compounds may directly affect the function of GCs in the ovary. Considering that humans are exposed to multiple pollutants simultaneously, we elucidated the effects of a mixture of endocrine-disrupting chemicals (EDCs) on human granulosa HGrC1 cells. The EDC mixture directly increased progesterone secretion by upregulating 3β-hydroxysteroid dehydrogenase (3βHSD) expression. Furthermore, the EDC mixture increased activity of mitochondria, which are the central sites for steroid hormone biosynthesis, and the ATP content. Unexpectedly, the EDC mixture reduced glucose transporter 4 (GLUT4) expression and perturbed glucose uptake; however, this did not affect the glycolytic rate. Moreover, inhibition of GLUT1 by STF-31 did not alter the effects of the EDC mixture on steroid secretion but decreased basal estradiol secretion. Taken together, our results demonstrate that the mixture of EDCs present in FF can alter the functions of human GCs by disrupting steroidogenesis and may thus adversely affect female reproductive health. This study highlights that the EDC mixture elicits its effects by targeting mitochondria and increases mitochondrial network formation, mitochondrial activity, and expression of 3βHSD, which is associated with the inner mitochondrial membrane.

Adverse effect of superoxide-induced mitochondrial damage in granulosa cells on follicular development in mouse ovaries

High mitochondrial oxidative phosphorylation (mt-OXPHOS) levels are required to supply the ATP necessary for follicle-stimulating hormone (FSH)-induced granulosa cell proliferation during the follicular development process. Consequently, excessive reactive oxygen species (ROS) might be generated and have an adverse effect on follicular health. This study aimed to elucidate the negative effects of ROS on mitochondrial functions in FSH-stimulated granulosa cells during the follicular development process and to investigate whether pyrroloquinoline quinone (PQQ) treatment could accelerate this process by ameliorating the adverse effects. To do this, both in vitro and in vivo experiments were performed with granulosa cells from superovulated immature (3-week-old) mice that were pretreated with or without PQQ, and a natural mating study was also performed. The ROS level in FSH-/eCG-stimulated granulosa cells was significantly increased. Moreover, high oxidative stress and mtDNA damage levels were evident in the granulosa cells. PQQ treatment not only reduced the ROS and oxidative stress levels but also ameliorated mtDNA damage, accelerated FSH-/eCG-induced ATP production, and increased the mitochondrial membrane potential and the expression levels of mitochondrial genes (Nd1, Cytb, Cox1, ATPase6) and the mt-ND1 protein. Accordingly, the proliferation and viability of granulosa cells, numbers of healthy preovulatory follicles and ovulated oocytes and serum estrogen level were significantly improved, while the apoptosis of granulosa cells was reduced. However, PQQ treatment did not change the fertility parameters in mature mice with natural cycles but did significantly increased the number of offspring born per delivery. These results revealed that ROS-associated damage in FSH-stimulated granulosa cells adversely affects their physiology and follicular health during the follicular development process. Treatment with PQQ is a beneficial tool to increase both the number of ovulated oocytes and pups per delivery.

Ovarian Aging: Molecular Mechanisms and Medical Management

This is a short review of the basic molecular mechanisms of ovarian aging, written with a particular focus on the use of this data to improve the diagnostic and therapeutic protocols both for women affected by physiological (age-related) ovarian decay and for those suffering premature ovarian insufficiency. Ovarian aging has a genetic basis that conditions the ovarian activity via a plethora of cell-signaling pathways that control the functions of different types of cells in the ovary. There are various factors that can influence these pathways so as to reduce their efficiency. Oxidative stress, often related to mitochondrial dysfunction, leading to the apoptosis of ovarian cells, can be at the origin of vicious circles in which the primary cause feeds back other abnormalities, resulting in an overall decline in the ovarian activity and in the quantity and quality of oocytes. The correct diagnosis of the molecular mechanisms involved in ovarian aging can serve to design treatment strategies that can slow down ovarian decay and increase the quantity and quality of oocytes that can be obtained for an in vitro fertilization attempt. The available treatment options include the use of antioxidants, melatonin, growth hormones, and mitochondrial therapies. All of these treatments have to be considered in the context of each couple's history and current clinical condition, and a customized (patient-tailored) treatment protocol is to be elaborated.

Ovarian Aging: Role of Pituitary-Ovarian Axis Hormones and ncRNAs in Regulating Ovarian Mitochondrial Activity

The number of mitochondria in the oocyte along with their functions (e.g., energy production, scavenger activity) decline with age progression. Such multifaceted functions support several processes during oocyte maturation, ranging from energy supply to synthesis of the steroid hormones. Hence, it is hardly surprising that their impairment has been reported in both physiological and premature ovarian aging, wherein they are crucial players in the apoptotic processes that arise in aged ovaries. In any form, ovarian aging implies the progressive damage of the mitochondrial structure and activities as regards to ovarian germ and somatic cells. The imbalance in the circulating hormones and peptides (e.g., gonadotropins, estrogens, AMH, activins, and inhibins), active along the pituitary-ovarian axis, represents the biochemical sign of ovarian aging. Despite the progress accomplished in determining the key role of the mitochondria in preserving ovarian follicular number and health, their modulation by the hormonal signalling pathways involved in ovarian aging has been poorly and randomly explored. Yet characterizing this mechanism is pivotal to molecularly define the implication of mitochondrial dysfunction in physiological and premature ovarian aging, respectively. However, it is fairly difficult considering that the pathways associated with ovarian aging might affect mitochondria directly or by altering the activity, stability and localization of proteins controlling mitochondrial dynamics and functions, either unbalancing other cellular mediators, released by the mitochondria, such as non-coding RNAs (ncRNAs). We will focus on the mitochondrial ncRNAs (i.e., mitomiRs and mtlncRNAs), that retranslocate from the mitochondria to the nucleus, as active players in aging and describe their role in the nuclear-mitochondrial crosstalk and its modulation by the pituitary-ovarian hormone dependent pathways. In this review, we will illustrate mitochondria as targets of the signaling pathways dependent on hormones and peptides active along the pituitary/ovarian axis and as transducers, with a particular focus on the molecules retrieved in the mitochondria, mainly ncRNAs. Given their regulatory function in cellular activities we propose them as potential diagnostic markers and/or therapeutic targets.

The levels of follicular fluid cell-free mitochondrial DNA could serve as a biomarker for pregnancy success in patients with small ovarian endometriosis cysts: A case-control study

Ovarian endometriosis cyst (OEC) is caused by the growth of ectopic endometrium into the ovarian cortex, leading to disrupted ovarian cortical structures and infertility. Large OECs are usually surgically removed, and assisted reproductive technology (ART) is required for future pregnancy. The oocyte reserve and development of patients with small non-surgical OECs are unknown. In this study, we compared mitochondrial abnormality, ATPase and IF1 mRNA expression levels, and OXPHO complex proteins between OEC vs control mural granulosa cells (mGCs).OEC mGCs show fewer mitochondria per cell, a higher proportion of aberrant morphology, lower ATPase mRNA levels, higher IF1 mRNA levels, and impaired expression of 3 of the 5 critical proteins involved in the OXPHOS complex, compared with control mGCs. Cell-free mitochondrial DNA (cfmtDNA) levels are higher in the follicular fluid of patients with OEC and were inversely associated with the expression of mtDNA in mGCs and cumulus granulosa cells (cGCs).Taken together, this study indicates that small non-surgical OECs lead to poor quality of oocytes and subsequent embryos during ART compared with control, which was accompanied by mGC mitochondrial dysfunction. mGC and cGC mtDNA and FF cfmtDNA might serve as efficient biomarkers for the non-invasive prediction of pregnancy outcomes in patients with OEC undergoing ART.

Effect of aging on mitochondria and metabolism of bovine granulosa cells

This study investigated the effect of aging on mitochondria in granulosa cells (GCs) collected from the antral follicles of young and aged cows (25–50 months and over 140 months in age, respectively). When GCs were cultured under 20% O₂ for 4 days, mitochondrial DNA copy number (Mt-number), determined by real-time PCR, increased throughout the culture period, and the extent of increase was greater in the GCs of young cows than in those of old cows. In a second experiment, GCs were cultured under 20% O₂ for 24 h. Protein levels of TOMM20 and TFAM in GCs were lower in aged cows than in young cows, and the amount of reactive oxygen species and the mitochondrial membrane potential were higher, whereas ATP content and proliferation activity were lower, respectively. Glucose consumption and lactate production were higher in the GCs of aged cows than in those of young cows. When GCs were cultured under 5% or 20% O₂ for 24 h, low O₂ decreased ATP content and increased glucose consumption in GCs of both age groups compared with high O₂; however, low O₂ decreased the Mt-number only in the GCs of young cows. In conclusion, we show that aging affects mitochondrial quantity, function, and response to differential O₂ tensions in GCs.

TNFα-Erk1/2 signaling pathway-regulated SerpinE1 and SerpinB2 are involved in lipopolysaccharide-induced porcine granulosa cell proliferation

Lipopolysaccharide (LPS) is an inhibitory factor that causes hormonal imbalance and subsequently affects ovarian function and fertility in mammals. Previous studies have shown that the exposure of granulosa cells (GC) to LPS leads to steroidogenesis dysfunction. However, the effects of LPS on the viability of GC remain largely unclear. In the present study, we aimed to address this question and unveil the underlying molecular mechanisms using cultured porcine GC. Results showed that GC proliferation and tumor necrosis factor α (TNFα) secretion were significantly increased after exposure to LPS, and these effects were completely reversed by blocking the TNFα sheddase, ADAM17. Moreover, GC proliferation induced by LPS was mimicked by treatment with recombinant TNFα. In addition, SerpinE1 and SerpinB2 expression levels increased in GC after treatment with LPS or recombinant TNFα, whereas blocking the Erk1/2 pathway completely abolished these effects and also inhibited GC proliferation. Further, consistent with the effects of blocking the Erk1/2 pathway, cell proliferation was completely inhibited by knocking down SerpinE1 or SerpinB2 in the presence of LPS or recombinant TNFα. Mitochondrial membrane potential (MMP) polarization in GC was increased by LPS or recombinant TNFα treatment, and these changes were completely negated by Erk1/2 inhibition, but not by SerpinE1 or SerpinB2 knockdown. Taken together, these results suggested that the TNFα-mediated upregulation of SerpinE1 and SerpinB2, through activation of the Erk1/2 pathway plays a crucial role in LPS-stimulated GC proliferation, and the increase in GC MMP may synergistically influence this process.

Negative effects of ROS generated during linear sperm motility on gene expression and ATP generation in boar sperm mitochondria

Mitochondrial oxidative phosphorylation (OXPHOS) is essential for ATP production to maintain sperm linear motility during migration from the uterus to the oviduct. However, ROS are generated as by-products of OXPHOS, causing stress and damaging the sperm quality. This study aimed to clarify the ROS targets in sperm mitochondria that decrease linear motility and to investigate whether mitochondria-target antioxidants (PQQ and CoQ10) affect mitochondrial activity and sperm motility. Sperm linear motility pattern, ATP production, and mitochondrial activity were decreased with increasing ROS levels during incubation in the low-glucose medium. However, sperm motility patterns and ROS levels were not significantly changed in the high-glucose medium. Moreover, the gene expression system (mt-DNA, mitochondrial transcription factor-A (TFAM) and RNA polymerase (POLRMT)) in sperm mitochondria was damaged during incubation in the low-glucose medium. Interestingly, PQQ treatment increased the mt-DNA stability and decreased the damage to TFAM and POLRMT, which resulted in high expression of mitochondrial genes. Furthermore, the antioxidants increased mitochondrial activity and maintained sperm linear motility under the low glucose condition. These results revealed that both ATP production and the mitochondrial transcription system are damaged with increasing ROS levels in sperm that show a linear motility pattern. Treatment with antioxidants, such as PQQ and CoQ10, is beneficial tool to maintain sperm linear motility.