Mitochondrial Dysfunction and Ovarian Aging

Gut microbiota modulation: a narrative review on a novel strategy for prevention and alleviation of ovarian aging

The global rise in life expectancy corresponds with a delay in childbearing age among women. Ovaries, seen as the chronometers of female physiological aging, demonstrate features of sped up aging, evidenced by the steady decline in both the quality and quantity of ovarian follicles from birth. The multifaceted pathogenesis of ovarian aging has kindled intensive research interest from the biomedical and pharmaceutical sectors. Novel studies underscore the integral roles of gut microbiota in follicular development, lipid metabolism, and hormonal regulation, forging a nexus with ovarian aging. In this review, we outline the role of gut microbiota in ovarian function (follicular development, oocyte maturation, and ovulation), compile and present gut microbiota alterations associated with age-related ovarian aging. We also discuss potential strategies for alleviating ovarian aging from the perspective of gut microbiota, such as fecal microbiota transplantation and probiotics.

Ceria Nanoparticle Systems Alleviate Degenerative Changes in Mouse Postovulatory Aging Oocytes by Reducing Oxidative Stress and Improving Mitochondrial Functions

Postovulatory aging oocytes usually feature diminished potential for fertilization and poor embryonic development due to enhanced oxidative damage to the subcellular organelles and macromolecules, which stands as a formidable obstacle in assisted reproductive technologies (ART). Here, we developed lipoic acid (LA) and polyethylene glycol (PEG)-modified CeO2 nanoparticles (LA-PEG-CeNPs) with biocompatibility, enzyme-like autocatalytic activity, and free radical scavenging capacity. We further investigated the LA-PEG-CeNPs effect in mouse postovulatory oocytes during in vitro aging. The results showed that LA-PEG-CeNPs dramatically reduced the accumulation of ROS in aging oocytes, improving mitochondrial dysfunction; they also down-regulated the pro-apoptotic activity by rectifying cellular caspase-3, cleaved caspase-3, and Bcl-2 levels. Consistently, this nanoenzyme prominently alleviated the proportion of abnormalities in spindle structure, chromosome alignment, microtubule stability, and filamentous actin (F-actin) distribution in aging oocytes, furthermore decreased oocyte fragmentation, and improved its ability of fertilization and development to blastocyst. Taken together, our finding suggests that LA-PEG-CeNPs can alleviate oxidative stress damage on oocyte quality during postovulatory aging, implying their potential value for clinical practice in assisted reproduction.

Electro-Metabolic Coupling of Cumulus-Oocyte Complex

Oocyte-cumulus cell interaction is essential for oocyte maturation and competence. The bidirectional crosstalk network mediated by gap junctions is fundamental for the metabolic cooperation between these cells. As cumulus cells exhibit a more glycolytic phenotype, they can provide metabolic substrates that the oocyte can use to produce ATP via oxidative phosphorylation. The impairment of mitochondrial activity plays a crucial role in ovarian aging and, thus, in fertility, determining the success or failure of assisted reproductive techniques. This review aims to deepen the knowledge about the electro-metabolic coupling of the cumulus-oocyte complex and to hypothesize a putative role of potassium channel modulators in order to improve fertility, promote intracellular Ca2+ influx, and increase the mitochondrial biogenesis and resulting ATP levels in cumulus cells.

Independent organelle and organelle-organelle interactions: essential mechanisms for malignant gynecological cancer cell survival

Different eukaryotic cell organelles (e.g., mitochondria, endoplasmic reticulum, lysosome) are involved in various cancer processes, by dominating specific cellular activities. Organelles cooperate, such as through contact points, in complex biological activities that help the cell regulate energy metabolism, signal transduction, and membrane dynamics, which influence survival process. Herein, we review the current studies of mechanisms by which mitochondria, endoplasmic reticulum, and lysosome are related to the three major malignant gynecological cancers, and their possible therapeutic interventions and drug targets. We also discuss the similarities and differences of independent organelle and organelle-organelle interactions, and their applications to the respective gynecological cancers; mitochondrial dynamics and energy metabolism, endoplasmic reticulum dysfunction, lysosomal regulation and autophagy, organelle interactions, and organelle regulatory mechanisms of cell death play crucial roles in cancer tumorigenesis, progression, and response to therapy. Finally, we discuss the value of organelle research, its current problems, and its future directions.

Pyrroloquinoline quinone promotes human mesenchymal stem cell-derived mitochondria to improve premature ovarian insufficiency in mice through the SIRT1/ATM/p53 pathway

BACKGROUND

DNA damage and oxidative stress induced by chemotherapy are important factors in the onset of premature ovarian insufficiency (POI). Studies have shown that mitochondria derived from mesenchymal stem cells (MSC-Mito) are beneficial for age-related diseases, but their efficacy alone is limited. Pyrroloquinoline quinone (PQQ) is a potent antioxidant with significant antiaging and fertility enhancement effects. This study aimed to investigate the therapeutic effect of MSC-Mito in combination with PQQ on POI and the underlying mechanisms involved.

METHODS

A POI animal model was established in C57BL/6J mice by cyclophosphamide and busulfan. The effects of MSC-Mito and PQQ administration on the estrous cycle, ovarian pathological damage, sex hormone secretion, and oxidative stress in mice were evaluated using methods such as vaginal smears and ELISAs. Western blotting and immunohistochemistry were used to assess the expression of SIRT1, PGC-1α, and ATM/p53 pathway proteins in ovarian tissues. A cell model was constructed using KGN cells treated with phosphoramide mustard to investigate DNA damage and apoptosis through comet assays and flow cytometry. SIRT1 siRNA was transfected into KGN cells to further explore the role of the SIRT1/ATM/p53 pathway in combination therapy with MSC-Mito and PQQ for POI.

RESULTS

The combined treatment of MSC-Mito and PQQ significantly restored ovarian function and antioxidant capacity in mice with POI. This treatment also reduced the loss of follicles at various stages, improving the disrupted estrous cycle. In vitro experiments demonstrated that PQQ facilitated the proliferation of MitoTracker-labelled MSC-Mito, synergistically restoring mitochondrial function and inhibiting oxidative stress in combination with MSC-Mito. Both in vivo and in vitro, the combination of MSC-Mito and PQQ increased mitochondrial biogenesis mediated by SIRT1 and PGC-1α while inhibiting the activation of ATM and p53, consequently reducing DNA damage-mediated cell apoptosis. Furthermore, pretreatment of KGN cells with SIRT1 siRNA reversed nearly all the aforementioned changes induced by the combined treatment.

CONCLUSIONS

Our research findings indicate that PQQ facilitates MSC-Mito proliferation and, in combination with MSC-Mito, ameliorates chemotherapy-induced POI through the SIRT1/ATM/p53 signaling pathway.

The close relationship between oocyte aging and telomere shortening, and possible interventions for telomere protection

As women delay childbearing due to socioeconomic reasons, understanding molecular mechanisms decreasing oocyte quantity and quality during ovarian aging becomes increasingly important. The ovary undergoes biological aging at a higher pace when compared to other organs. As is known, telomeres play crucial roles in maintaining genomic integrity, and their shortening owing to increased reactive oxygen species, consecutive cellular divisions, genetic and epigenetic alterations is associated with loss of developmental competence of oocytes. Novel interventions such as antioxidant treatments and regulation of gene expression are being investigated to prevent or rescue telomere attrition and thereby oocyte aging. Herein, potential factors and molecular mechanisms causing telomere shortening in aging oocytes were comprehensively reviewed. For the purpose of extending reproductive lifespan, possible therapeutic interventions to protect telomere length were also discussed.

Disruption of mitochondrial unfolded protein response results in telomere shortening in mouse oocytes and somatic cells

Caseinolytic peptidase P (CLPP) plays a central role in mitochondrial unfolded protein response (mtUPR) by promoting the breakdown of misfolded proteins and setting in motion a cascade of reactions to re-establish protein homeostasis. Global germline deletion of Clpp in mice results in female infertility and accelerated follicular depletion. Telomeres are tandem repeats of 5'-TTAGGG-3' sequences found at the ends of the chromosomes. Telomeres are essential for maintaining chromosome stability during somatic cell division and their shortening is associated with cellular senescence and aging. In this study, we asked whether the infertility and ovarian aging phenotype caused by global germline deletion of Clpp is associated with somatic aging, and tested telomere length in tissues of young and aging mice. We found that impaired mtUPR caused by the lack of CLPP is associated with accelerated telomere shortening in both oocytes and somatic cells of aging mice. In addition, expression of several genes that maintain telomere integrity was decreased, and double-strand DNA breaks were increased in telomeric regions. Our results highlight how impaired mtUPR can affect telomere integrity and demonstrate a link between loss of mitochondrial protein hemostasis, infertility, and somatic aging.

Mitochondrial Unfolded Protein Response Gene Clpp Is Required for Oocyte Function and Female Fertility

Mitochondrial unfolded protein stress response (mtUPR) plays a critical role in regulating cellular and metabolic stress response and helps maintain protein homeostasis. Caseinolytic peptidase P (CLPP) is one of the key regulators of mtUPR and promotes unfolded protein degradation. Previous studies demonstrated that global deletion of Clpp resulted in female infertility, whereas no impairment was found in the mouse model with targeted deletion of Clpp in cumulus/granulosa cells. These results suggest the need to delineate the function of Clpp in oocytes. In this study, we aimed to further explore the role of mtUPR in female reproductive competence and senescence using a mouse model. Oocyte-specific targeted deletion of Clpp in mice resulted in female subfertility associated with metabolic and functional abnormalities in oocytes, thus highlighting the importance of CLPP-mediated protein homeostasis in oocyte competence and reproductive function.

Prolonged Supplementation of Ozonated Sunflower Oil Bestows an Antiaging Effect, Improves Blood Lipid Profile and Spinal Deformities, and Protects Vital Organs of Zebrafish (Danio rerio) against Age-Related Degeneration: Two-Years Consumption Study

Ozonated sunflower oil (OSO) is renowned for its diverse therapeutic benefits. Nonetheless, the consequences of extended dietary intake of OSO have yet to be thoroughly investigated. Herein, the effect of 2-year dietary supplementation of OSO was examined on the survivability, obesity, skeletal deformities, swimming behavior, and liver, kidney, ovary, and testis function of zebrafish. Results showed that the zebrafish feed supplemented with 20% (wt/wt) OSO for 2 years emerged with higher survivability and body weight management compared to sunflower oil (SO) and normal diet (ND)-supplemented zebrafish. Radio imaging (X-ray)-based analysis revealed 2.6° and 15.2° lower spinal curvature in the OSO-supplemented groups than in the SO and ND-supplemented groups; consistently, OSO-supplemented zebrafish showed better swimming behavior. The histology analysis of the liver revealed the least fatty liver change and interleukin (IL)-6 generation in the OSO-supplemented group. Additionally, a significantly lower level of reactive oxygen species (ROS), apoptotic, and senescent cells were observed in the liver of the OSO-supplemented zebrafish. Also, no adverse effect on the kidney, testis, and ovary morphology was detected during 2 years of OSO consumption. Moreover, lower senescence with diminished ROS and apoptosis was noticed in the kidney and ovary in response to OSO consumption. The OSO supplementation was found to be effective in countering age-associated dyslipidemia by alleviating total cholesterol (TC), triglycerides (TG), low-density lipoproteins (LDL-C) and elevating high-density lipoproteins (HDL-C)/TC levels. Conclusively, prolonged OSO consumption showed no adverse effect on the morphology and functionality of vital organs; in fact, OSO supplementation displayed a protective effect against age-associated detrimental effects on spinal deformities, vital organ functionality, cell senescence, and the survivability of zebrafish.

Effects of BXSMD on ESR1 and ESR2 expression in CSD female mice

ETHNIC PHARMACOLOGICAL RELEVANCE

Due to the rapid pace of modern society, chronic insomnia has become universal phenomenon. In China, Banxia Shumi Decoction (BXSMD) has been used in treating chronic insomnia for thousands of years, but its chemical composition and action mechanism are still unknown.

AIM OF THE STUDY

This study aims to explore the chemical composition of BXSMD and its effects on Estrogen receptor 1 (ESR1) and Estrogen receptor 2 (ESR2) in mice with chronic sleep deprivation (CSD).

MATERIALS AND METHODS

UHPLC-Q-Orbitrap-MS/MS was applied in determining the chemical composition of BXSMD. After 21-day sleep deprivation (SD) in platform water environment, CSD mice model was prepared. By conducting open field test, 24-h autonomic diurnal and nocturnal activity of mice in each group was detected. ELISA was employed to measure the contents of 5-HT, DA, NE, GABA, Glu, and MT. With RT-PCR, Western blot (WB), and immunohistochemistry (IHC), mRNA and protein expressions of ESR1 and ESR2 in the hypothalamus and hippocampus were tested.

RESULTS

BXSMD included ferulic acid, kaverol, daidzein, apigenin, berberine, adenosine, aesculin, vanillin, naringin, and glycine, which might constitute the material basis forthe improvement of chronic insomnia. With BXSMD, the total moving distance and the rest time in dark period of CSD mice were shortened, while its rest time in light period was increased. Besides, BXSMD enhanced the contents of 5-HT, GABA, and MT in CSD mice, and decreased the contents of Glu, NE, and DA. BXSMD elevated the mRNA of Esr1 and Esr2, and elevated the protein expressions of ESR1 and ESR2 in the hypothalamus and hippocampus of CSD mice.

CONCLUSIONS

BXSMD contains various chemical components for sleep-wake regulation, with the mechanism of stimulating estrogen signaling pathway by regulating the expressions of ESR1 and ESR2, ultimately realizing the regulation to sleep-wake disorder caused by CSD.

ErZhiTianGui Decoction alleviates age-related ovarian aging by regulating mitochondrial homeostasis and inhibiting ferroptosis

AIM

This study was designed to investigate the pharmacological effects and mechanisms of ErZhiTianGui Decoction (EZTG) for age-related ovarian aging in mice.

METHODS

This study used naturally aging mice as a model, and EZTG was used for intragastric administration. Ovarian pathological changes, as well as follicular reserve were assessed by hematoxylin and eosin staining, and serum hormone levels (anti-mullerian hormone, follicle-stimulating hormone), mitochondrial reactive oxygen species (ROS) and mitochondrial DNA (mtDNA) damage marker 8-hydroxy-2'-deoxyguanosine(8-OHdG), and lipid peroxidation markers glutathione(GSH) and malondialdehyde(MDA) were determined by enzyme-linked immunosorbent assay. Mitochondrial membrane potential (MMP) levels in ovaries were determined using flow cytometry. The levels of PINK1 and Parkin were observed using immunofluorescence staining. Mitochondrial-derived vesicles (MDVs) and mitochondrial morphology were observed using electron microscopy. Prussian blue staining was used to observe iron ion aggregation in ovarian tissue. The Iron assay kits detected total iron levels. Western blot was used to detect the expression of proteins related to mitochondrial and ferroptosis related genes.

RESULTS

After EZTG treatment, aged mice showed increased ovarian reserve, improved serum hormone levels, increased MMP, GSH levels, and decreased mitochondrial ROS, 8-OHdG, and MDA levels. Immunofluorescence staining showed decreased levels of PINK1 and Parkin, and the same trend was observed for the Western blot. Meanwhile, electron microscopy showed that EZTG improved the mitochondrial morphology in the ovaries of aged mice. EZTG also decreased the total iron and protein levels of Acyl-CoA synthetase long-chain family4 (ACSL4) and increased the protein level of glutathione peroxidase 4 (GPX4) in the ovaries of aged mice.

CONCLUSIONS

EZTG can maintain PINK1/Parkin-mediated mitochondrial homeostasis, reduce the lipid peroxidation caused by the accumulation of ROS, and inhibit the occurrence of ferroptosis and delaying ovarian aging. These findings suggest that EZTG may be a promising drug for treating age-related ovarian aging in females.

NADase CD38 is a key determinant of ovarian aging

The ovary ages earlier than most other tissues, yet the underlying mechanisms remain elusive. Here a comprehensive analysis of transcriptomic landscapes in different organs in young and middle-aged mice revealed that the ovaries showed earlier expression of age-associated genes, identifying increased NADase CD38 expression and decreased NAD+ levels in the ovary of middle-aged mice. Bulk and single-cell RNA sequencing revealed that CD38 deletion mitigated ovarian aging, preserving fertility and follicle reserve in aged mice by countering age-related gene expression changes and intercellular communication alterations. Mechanistically, the earlier onset of inflammation induced higher expression levels of CD38 and decreased NAD+ levels in the ovary, thereby accelerating ovarian aging. Consistently, pharmacological inhibition of CD38 enhanced fertility in middle-aged mice. Our findings revealed the mechanisms underlying the earlier aging of the ovary relative to other organs, providing a potential therapeutic target for ameliorating age-related female infertility.

New Concepts in the Manipulation of the Aging Process

This review explores the current concepts in aging and then goes on to describe a novel, ground-breaking technology which will change the way we think about and manage aging. The foundation of the review is based on the work carried out on the QiLaser activation of human Very Small Embryonic Like (hVSEL) pluripotent stem cells in autologous Platelet Rich Plasma (PRP), known as the Qigeneration Procedure. The application of this technology in anti-aging technology is discussed with an emphasis on epigenetic changes during aging focusing on DNA methylation.

Autologous non-invasively derived stem cells mitochondria transfer shows therapeutic advantages in human embryo quality rescue

BACKGROUND

The decline in the quantity and quality of mitochondria are closely associated with infertility, particularly in advanced maternal age. Transferring autologous mitochondria into the oocytes of infertile females represents an innovative and viable strategy for treating infertility, with no concerns regarding ethical considerations. As the donor cells of mitochondria, stem cells have biological advantages but research and evidence in this area are quite scarce.

METHODS

To screen out suitable human autologous ooplasmic mitochondrial donor cells, we performed comprehensive assessment of mitochondrial physiology, function and metabolic capacity on a varity of autologous adipose, marrow, and urine-derived mesenchymal stromal cells (ADSC, BMSC and USC) and ovarian germline granulosa cells (GC). Further, to explore the biosafety, effect and mechanism of stem cell-derived mitochondria transfer on human early embryo development, randomized in-vitro basic studies were performed in both of the young and aged oocytes from infertile females.

RESULTS

Compared with other types of mesenchymal stromal cells, USC demonstrated a non-fused spherical mitochondrial morphology and low oxidative stress status which resembled the oocyte stage. Moreover, USC mitochondrial content, activity and function were all higher than other cell types and less affected by age, and it also exhibited a biphasic metabolic pattern similar to the pre-implantation stage of embryonic development. After the biosafety identification of the USC mitochondrial genome, early embryos after USC mitochondrial transfer showed improvements in mitochondrial content, activity, and cytoplasmic Ca2+ levels. Further, aging embryos also showed improvements in embryonic morphological indicators, euploidy rates, and oxidative stress status.

CONCLUSION

Autologous non-invasively derived USC mitochondria transfer may be an effective strategy to improve embryonic development and metabolism, especially in infertile females with advanced age or repeated pregnancy failure. It provides evidence and possibility for the autologous treatment of infertile females without invasive and ethical concerns.

Paxillin knockout in mouse granulosa cells increases fecundity†

Paxillin is an intracellular adaptor protein involved in focal adhesions, cell response to stress, steroid signaling, and apoptosis in reproductive tissues. To investigate the role of paxillin in granulosa cells, we created a granulosa-specific paxillin knockout mouse model using Cre recombinase driven by the Anti-Müllerian hormone receptor 2 gene promoter. Female granulosa-specific paxillin knockout mice demonstrated increased fertility in later reproductive age, resulting in higher number of offspring when bred continuously up to 26 weeks of age. This was not due to increased numbers of estrous cycles, ovulated oocytes per cycle, or pups per litter, but this was due to shorter time to pregnancy and increased number of litters in the granulosa-specific paxillin knockout mice. The number of ovarian follicles was not significantly affected by the knockout at 30 weeks of age. Granulosa-specific paxillin knockout mice had slightly altered estrous cycles but no difference in circulating reproductive hormone levels. Knockout of paxillin using clustered regularly interspaced short palindromic repeat-associated protein 9 (CRISPR-Cas9) in human granulosa-derived immortalized KGN cells did not affect cell proliferation or migration. However, in cultured primary mouse granulosa cells, paxillin knockout reduced cell death under basal culture conditions. We conclude that paxillin knockout in granulosa cells increases female fecundity in older reproductive age mice, possibly by reducing granulosa cell death. This study implicates paxillin and its signaling network as potential granulosa cell targets in the management of age-related subfertility.

Human ovarian aging is characterized by oxidative damage and mitochondrial dysfunction

STUDY QUESTION

Are human ovarian aging and the age-related female fertility decline caused by oxidative stress and mitochondrial dysfunction in oocytes?

SUMMARY ANSWER

We found oxidative damage in oocytes of advanced maternal age, even at the primordial follicle stage, and confirmed mitochondrial dysfunction in such oocytes, which likely resulted in the use of alternative energy sources.

WHAT IS KNOWN ALREADY

Signs of reactive oxygen species-induced damage and mitochondrial dysfunction have been observed in maturing follicles, and even in early stages of embryogenesis. However, although recent evidence indicates that also primordial follicles have metabolically active mitochondria, it is still often assumed that these follicles avoid oxidative phosphorylation to prevent oxidative damage in dictyate arrested oocytes. Data on the influence of ovarian aging on oocyte metabolism and mitochondrial function are still limited.

STUDY DESIGN, SIZE, DURATION

A set of 39 formalin-fixed and paraffin-embedded ovarian tissue biopsies were divided into different age groups and used for immunofluorescence analysis of oxidative phosphorylation activity and oxidative damage to proteins, lipids, and DNA. Additionally, 150 immature oocytes (90 germinal vesicle oocytes and 60 metaphase I oocytes) and 15 cumulus cell samples were divided into different age groups and used for targeted metabolomics and lipidomics analysis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Ovarian tissues used for immunofluorescence microscopy were collected through PALGA, the nationwide network, and registry of histo- and cytopathology in The Netherlands. Comprehensive metabolomics and lipidomics were performed by liquid-liquid extraction and full-scan mass spectrometry, using oocytes and cumulus cells of women undergoing ICSI treatment based on male or tubal factor infertility, or fertility preservation for non-medical reasons.

MAIN RESULTS AND THE ROLE OF CHANCE

Immunofluorescence imaging on human ovarian tissue indicated oxidative damage by protein and lipid (per)oxidation already at the primordial follicle stage. Metabolomics and lipidomics analysis of oocytes and cumulus cells in advanced maternal-age groups demonstrated a shift in the glutathione-to-oxiglutathione ratio and depletion of phospholipids. Age-related changes in polar metabolites suggested a decrease in mitochondrial function, as demonstrated by NAD+, purine, and pyrimidine depletion, while glycolysis substrates and glutamine accumulated, with age. Oocytes from women of advanced maternal age appeared to use alternative energy sources like glycolysis and the adenosine salvage pathway, and possibly ATP which showed increased production in cumulus cells.

LIMITATIONS, REASONS FOR CAUTION

The immature oocytes used in this study were all subjected to ovarian stimulation with high doses of follicle-stimulating hormones, which might have concealed some age-related differences.

WIDER IMPLICATIONS OF THE FINDINGS

Further studies on how to improve mitochondrial function, or lower oxidative damage, in oocytes from women of advanced maternal age, for instance by supplementation of NAD+ precursors to promote mitochondrial biogenesis, are warranted. In addition, supplementing the embryo medium of advanced maternal-age embryos with such compounds could be a treatment option worth exploring.

STUDY FUNDING/COMPETING INTEREST(S)

The study was funded by the Amsterdam UMC. The authors declare to have no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Human follicular fluid elicits select dose- and age-dependent effects on mouse oocytes and cumulus-oocyte complexes in a heterologous in vitro maturation assay

Follicular fluid (FF) is a primary microenvironment of the oocyte within an antral follicle. Although several studies have defined the composition of human FF in normal physiology and determined how it is altered in disease states, the direct impacts of human FF on the oocyte are not well understood. The difficulty of obtaining suitable numbers of human oocytes for research makes addressing such a question challenging. Therefore, we used a heterologous model in which we cultured mouse oocytes in human FF. To determine whether FF has dose-dependent effects on gamete quality, we performed in vitro maturation of denuded oocytes from reproductively young mice (6-12 weeks) in 10%, 50%, or 100% FF from participants of mid-reproductive age (32-36 years). FF impacted meiotic competence in a dose-dependent manner, with concentrations >10% inhibiting meiotic progression and resulting in spindle and chromosome alignment defects. We previously demonstrated that human FF acquires a fibro-inflammatory cytokine signature with age. Thus, to determine whether exposure to an aging FF microenvironment contributes to the age-dependent decrease in gamete quality, we matured denuded oocytes and cumulus-oocyte complexes (COCs) in FF from reproductively young (28-30 years) and old (40-42 years) participants. FF decreased meiotic progression of COCs, but not oocytes, from reproductively young and old (9-12 months) mice in an age-dependent manner. Moreover, FF had modest age-dependent impacts on mitochondrial aggregation in denuded oocytes and cumulus layer expansion dynamics in COCs, which may influence fertilization or early embryo development. Overall, these findings demonstrate that acute human FF exposure can impact select markers of mouse oocyte quality in both dose- and age-dependent manners.

Mitigating Age-Related Ovarian Dysfunction with the Anti-Inflammatory Agent MIT-001

Ovarian aging is a major obstacle in assisted reproductive medicine because it leads to ovarian dysfunction in women of advanced age. Currently, there are no effective treatments to cure age-related ovarian dysfunction. In this study, we investigated the effect of MIT-001 on the function of aged ovaries. Young and old mice were utilized in this study. MIT-001 was intraperitoneally administered, and the number of follicles and oocytes was analyzed. Each group was then retrieved for RNA and protein isolation. Total RNA was subjected to mRNA next-generation sequencing. Protein extracts from ovarian lysates were used to evaluate various cytokine levels in the ovaries. MIT-001 enhanced follicles and the number of oocytes were compared with non-treated old mice. MIT-001 downregulated immune response-related transcripts and cytokines in the ovaries of old mice. MIT-001 modulates the immune complex responsible for generating inflammatory signals and has the potential to restore the function of old ovaries and improve female fertility.

Protective effect of onion peel extract on ageing mouse oocytes

Mammalian oocytes not fertilized immediately after ovulation can undergo ageing and a rapid decline in quality. The addition of antioxidants can be an efficient approach to delaying the oocyte ageing process. Onion peel extract (OPE) contains quercetin and other flavonoids with natural antioxidant activities. In this study, we investigated the effect of OPE on mouse oocyte ageing and its mechanism of action. The oocytes were aged in vitro in M16 medium for 16 h after adding OPE at different concentrations (0, 50, 100, 200, and 500 μg/ml). The addition of 100 μg/ml OPE reduced the oocyte fragmentation rate, decreased the reactive oxygen species (ROS) level, increased the glutathione (GSH) level, and improved the mitochondrial membrane potential compared with the control group. The addition of OPE also increased the expression of SOD1, CAT, and GPX3 genes, and the caspase-3 activity in OPE-treated aged oocytes was significantly lower than that in untreated aged oocytes and similar to that in fresh oocytes. These results indicated that OPE delayed mouse oocyte ageing by reducing oxidative stress and apoptosis and enhancing mitochondrial function.

Facilitation of Ovarian Response by Mechanical Force-Latest Insight on Fertility Improvement in Women with Poor Ovarian Response or Primary Ovarian Insufficiency

The decline in fertility in aging women, especially those with poor ovarian response (POR) or primary ovarian insufficiency (POI), is a major concern for modern IVF centers. Fertility treatments have traditionally relied on gonadotropin- and steroid-hormone-based IVF practices, but these methods have limitations, especially for women with aging ovaries. Researchers have been motivated to explore alternative approaches. Ovarian aging is a complicated process, and the deterioration of oocytes, follicular cells, the extracellular matrix (ECM), and the stromal compartment can all contribute to declining fertility. Adjunct interventions that involve the use of hormones, steroids, and cofactors and gamete engineering are two major research areas aimed to improve fertility in aging women. Additionally, mechanical procedures including the In Vitro Activation (IVA) procedure, which combines pharmacological activators and fragmentation of ovarian strips, and the Whole Ovary Laparoscopic Incision (WOLI) procedure that solely relies on mechanical manipulation in vivo have shown promising results in improving follicle growth and fertility in women with POR and POI. Advances in the use of mechanical procedures have brought exciting opportunities to improve fertility outcomes in aging women with POR or POI. While the lack of a comprehensive understanding of the molecular mechanisms that lead to fertility decline in aging women remains a major challenge for further improvement of mechanical-manipulation-based approaches, recent progress has provided a better view of how these procedures promote folliculogenesis in the fibrotic and avascular aging ovaries. In this review, we first provide a brief overview of the potential mechanisms that contribute to ovarian aging in POI and POR patients, followed by a discussion of measures that aim to improve ovarian folliculogenesis in aging women. At last, we discuss the likely mechanisms that contribute to the outcomes of IVA and WOLI procedures and potential future directions.

Aging and oocyte competence: A molecular cell perspective

Follicular microenvironment is paramount in the acquisition of oocyte competence, which is dependent on two interconnected and interdependent processes: nuclear and cytoplasmic maturation. Extensive research conducted in human and model systems has provided evidence that those processes are disturbed with female aging. In fact, advanced maternal age (AMA) is associated with a lower chance of pregnancy and live birth, explained by the age-related decline in oocyte quality/competence. This decline has largely been attributed to mitochondria, essential for oocyte maturation, fertilization, and embryo development; with mitochondrial dysfunction leading to oxidative stress, responsible for nuclear and mitochondrial damage, suboptimal intracellular energy levels, calcium disturbance, and meiotic spindle alterations, that may result in oocyte aneuploidy. Nuclear-related mechanisms that justify increased oocyte aneuploidy include deoxyribonucleic acid (DNA) damage, loss of chromosomal cohesion, spindle assembly checkpoint dysfunction, meiotic recombination errors, and telomere attrition. On the other hand, age-dependent cytoplasmic maturation failure is related to mitochondrial dysfunction, altered mitochondrial biogenesis, altered mitochondrial morphology, distribution, activity, and dynamics, dysmorphic smooth endoplasmic reticulum and calcium disturbance, and alterations in the cytoskeleton. Furthermore, reproductive somatic cells also experience the effects of aging, including mitochondrial dysfunction and DNA damage, compromising the crosstalk between granulosa/cumulus cells and oocytes, also affected by a loss of gap junctions. Old oocytes seem therefore to mature in an altered microenvironment, with changes in metabolites, ribonucleic acid (RNA), proteins, and lipids. Overall, understanding the mechanisms implicated in the loss of oocyte quality will allow the establishment of emerging biomarkers and potential therapeutic anti-aging strategies. This article is categorized under: Reproductive System Diseases > Molecular and Cellular Physiology.

SIRT6 reduces the symptoms of premature ovarian failure and alleviates oxidative stress and apoptosis in granulosa cells by degrading p66SHC via H3K9AC

CONTEXT

Substantial evidence suggests that ovarian oxidative stress can result in severe ovarian dysfunction.

OBJECTIVE

The purpose of this article is to investigate the potential of SIRT6 in alleviating premature ovarian failure (POF) by inhibiting oxidative stress.

METHODS

To mimic POF, mice were administered daily subcutaneous injections of d-galactose. The levels of E2, FSH, LH, AMH, and progesterone in serum were measured, along with changes in follicles and SIRT6 levels. Mice were treated with the SIRT6 agonist MDL-800, SIRT6 levels, follicles, and aforementioned hormones were reassessed. The effects of MDL-800 on oxidative stress and apoptosis were subsequently identified. Primary granulosa cells were isolated from mice, and the effects of H2O2 and MDL-800 on cell viability, oxidative stress, SIRT6 level, and apoptosis were evaluated. In addition, the regulation of SIRT6 on H3K9AC/p66SHC was verified by examining changes in protein levels, promoter activity, and the reversal effects of p66SHC overexpression.

RESULTS

MDL-800 mitigated hormone fluctuations, reduced follicle depletion in ovarian tissue, and attenuated oxidative stress and apoptosis in mice. In vitro experiments demonstrated that MDL-800 enhanced the resilience of primary granulosa cells against H2O2, as evidenced by increased cell viability and reduced oxidative stress and apoptosis. Furthermore, SIRT6 was found to decrease H3K9AC and p66SHC levels, as well as attenuate p66SHC promoter activity. The protective effects of MDL-800 on cells were reversed upon p66SHC overexpression.

CONCLUSION

In summary, this study highlights that activation of SIRT6 can alleviate POF and reduce oxidative stress by degrading H3K9AC and suppressing p66Shc levels in granulosa cells.

Insulin-like growth factor 1 promotes the gonadal development of Pampus argenteus by regulating energy metabolism†

Insulin-like growth factor 1 (Igf1) is known to promote ovarian maturation by interacting with other hormones. However, the limited research on the role of Igf1 in the energy metabolism supply of gonads has hindered further exploration. To explore the role of Igf1 in gonadal development of silver pomfret, we analyzed the expression levels and the localization of igf1 mRNA and protein during testicular and ovarian development of silver pomfret. The results of the study showed upregulation of Igf1 in the critical period of vitellogenesis and sperm meiosis, which was found to be mainly expressed in the somatic cells of the gonads. Upon adding E2 and Igf1 to cultured gonadal tissues, the expression of energy-related genes was significantly increased, along with the E2-enhanced effect of Igf1 in the testis. Importantly, stimulation of both ovaries and testes with E2 and Igf1 led to a remarkable increase in the expression of vitellogenesis and meiosis-related genes. Therefore, we conclude that Igf1 promotes vitellogenesis and sperm meiosis by regulating gonadal energy production. Moreover, the expression of Igf1 in gonads is significantly regulated by E2. These findings provide new insights for the research of Igf1 in fish breeding, thus allowing the regulation of energy metabolism between growth and reproduction for successful reproductive outcomes.

Near-infrared fluorophore IR-61 delays postovulatory aging of mouse oocytes through suppressing oxidative stress mediated by mitochondrial protection

Postovulatory aging can trigger deterioration of oocyte quality and subsequent embryonic development, and thus reduce the success rates of assisted reproductive technology (ART). The molecular mechanisms underlying postovulatory aging, and preventative strategies, remain to be explored. The near-infrared fluorophore IR-61, a novel heptamethine cyanine dye, has the potential for mitochondrial targeting and cell protection. In this study, we found that IR-61 accumulated in oocyte mitochondria and reduced the postovulatory aging-induced decline in mitochondrial function, including mitochondrial distribution, membrane potential, mtDNA number, ATP levels, and mitochondrial ultrastructure. In addition, IR-61 rescued postovulatory aging-caused oocyte fragmentation, defects in spindle structure, and embryonic developmental potential. RNA sequencing analysis indicated that the postovulatory aging-induced oxidative stress pathway might be inhibited by IR-61. We then confirmed that IR-61 decreased the levels of reactive oxygen species and MitoSOX, and increased GSH content in aged oocytes. Collectively, the results indicate that IR-61 may prevent postovulatory aging by rescuing oocyte quality, promoting successful rate in ART procedure.

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

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

Near-infrared fluorophore IR-61 improves the quality of oocytes in aged mice via mitochondrial protection

Maternal aging is associated with a decline in oocyte quality, which leads to the decreased fertility. Therefore, developing approaches to reduce aging-induced deterioration of oocyte quality in older women is important. Near-infrared cell protector-61 (IR-61), a novel heptamethine cyanine dye, has the potential for antioxidant effects. In this study, we found that IR-61 can accumulate in the ovaries and improved ovarian function of naturally aged mice; it also increased the oocyte maturation rate and quality by maintaining the integrity of the spindle/chromosomal structure and reducing the aneuploidy rate. In addition, the embryonic developmental competence of aged oocytes was improved. Finally, RNA-sequencing analysis indicated that IR-61 might perform the beneficial effects on aged oocytes by regulating mitochondrial function, this was confirmed by immunofluorescence analysis of mitochondrial distribution and reactive oxygen species. Taken together, our findings demonstrate that IR-61 supplementation in vivo can increase oocyte quality and protect oocytes from aging-induced mitochondrial dysfunction, and thus could improve the fertility of older women and efficiency of assisted reproductive technology.

Brown adipose tissue-derived exosomes delay fertility decline in aging mice

Introduction

Ovarian aging has steadily grown to be a significant health issue for women as a result of the increase in average life expectancy and the postponement of reproductive age. One of the important pathological foundations of ovarian aging is formed by mitochondrial dysfunction, which causes decreases in follicle quantity and oocyte quality. In recent years, brown adipose tissue (BAT) transplantation has been proven as an effective treatment for aging-related diseases, such as ovarian aging. However, BAT transplantation is an invasive operation with long-term risks. Therefore, we need to find an alternative strategy.

Methods

We injected BAT-derived exosomes into eight-month-old C57BL/6 female mice. The fertility was detected by the estrous cycle and mating test. The changes of ovary and oocyte were measured by ovarian volume, organ coefficient, follicle counting, and oocyte maturation rate. ROS level, mitochondrial membrane potential and ATP level were measured to analyze the mitochondrial function of oocytes. The changes in metabolism were explored by cold stimulation test, body weight and blood sugar. The possible molecular mechanism was further investigated by RNA sequencing.

Results

In terms of fertility, the estrous cycle of aging mice after BAT-derived exosome intervention was more regular, and the number of progenies and litters was increased. At the tissue level, the ovaries in the BAT-exosome group were larger, and the number of primordial follicles, secondary follicles, antral follicles and total follicles increased. At the cellular level, BAT-derived exosomes improved the maturation of oocytes in vivo and in vitro, increased the mitochondrial membrane potential and ATP levels of oocytes, and decreased ROS levels. Besides, BAT-derived exosomes ameliorated the metabolism and viability of aging mice. Furthermore, mRNA sequencing showed that BAT exosomes altered the expression levels of genes related to metabolism and the quality of oocytes.

Conclusion

BAT-derived exosomes enhanced mitochondrial function, promoted follicle survival, improved fertility, and extended ovarian lifespan in aging mice.

Identification and validation of hub genes and pathways associated with mitochondrial dysfunction in hypertrophy of ligamentum flavum

Background: Lumbar spinal stenosis which can lead to irreversible neurologic damage and functional disability, is characterized by hypertrophy of ligamentum flavum (HLF). Recent studies have indicated that mitochondrial dysfunction may contribute to the development of HLF. However, the underlying mechanism is still unclear. Methods: The dataset GSE113212 was obtained from the Gene Expression Omnibus database, and the differentially expressed genes were identified. The intersection of DEGs and mitochondrial dysfunction-related genes were identified as mitochondrial dysfunction-related DEGs. Gene Ontology analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and Gene Set Enrichment Analysis were performed. Protein-protein interaction network was constructed, and miRNAs and transcriptional factors of the hub genes were predicted via the miRNet database. Small molecule drugs targeted to these hub genes were predicted via PubChem. Immune infiltration analysis was performed to evaluate the infiltration level of immune cells and their correlation with the hub genes. In final, we measured the mitochondrial function and oxidative stress in vitro and verified the expression of hub genes by qPCR experiments. Results: In total, 43 genes were identified as MDRDEGs. These genes were mainly involved in cellular oxidation, catabolic processes, and the integrity of mitochondrial structure and function. The top hub genes were screened, including LONP1, TK2, SCO2, DBT, TFAM, MFN2. The most significant enriched pathways include cytokine-cytokine receptor interaction, focal adhesion, etc. Besides, SP1, PPARGC1A, YY1, MYC, PPARG, and STAT1 were predicted transcriptional factors of these hub genes. Additionally, increased immune infiltration was demonstrated in HLF, with a close correlation between hub genes and immune cells found. The mitochondrial dysfunction and the expression of hub genes were validated by evaluation of mitochondrial DNA, oxidative stress markers and quantitative real-time PCR. Conclusion: This study applied the integrative bioinformatics analysis and revealed the mitochondrial dysfunction-related key genes, regulatory pathways, TFs, miRNAs, and small molecules underlying the development of HLF, which improved the understanding of molecular mechanisms and the development of novel therapeutic targets for HLF.

The impact of epigenetic landscape on ovarian cells in infertile older women undergoing IVF procedures

The constant decline in fertility and older reproductive age is the major cause of low clinical pregnancy rates in industrialised countries. Epigenetic mechanisms impact on proper embryonic development in women undergoing in vitro fertilisation (IVF) protocols. Here, we describe the main epigenetic modifications that may influence female reproduction and could affect IVF success.

Biomarkers of aging

Aging biomarkers are a combination of biological parameters to (i) assess age-related changes, (ii) track the physiological aging process, and (iii) predict the transition into a pathological status. Although a broad spectrum of aging biomarkers has been developed, their potential uses and limitations remain poorly characterized. An immediate goal of biomarkers is to help us answer the following three fundamental questions in aging research: How old are we? Why do we get old? And how can we age slower? This review aims to address this need. Here, we summarize our current knowledge of biomarkers developed for cellular, organ, and organismal levels of aging, comprising six pillars: physiological characteristics, medical imaging, histological features, cellular alterations, molecular changes, and secretory factors. To fulfill all these requisites, we propose that aging biomarkers should qualify for being specific, systemic, and clinically relevant.

Lycopene attenuates D-galactose-induced cognitive decline by enhancing mitochondrial function and improving insulin signalling in the brains of female CD-1 mice

The incidence of neurodegenerative diseases is severely increasing with ageing. Lycopene (LYC), a carotenoid pigment, has been reported to have antioxidant, anti-inflammatory and neuroprotective properties. In the present study, we aimed to investigate the ameliorative effect of LYC on D-galactose (D-gal) induced cognitive defects and the underlying mechanisms. Forty-five female CD-1 mice (two months old) were separated into three groups to be fed with either a normal diet or a LYC diet (0.03%, w/w, mixed into normal diet). Meanwhile, the mice were treated by intraperitoneal injection of normal saline or D-gal 150 mg/kg/day for 8 weeks. The behavioural test results indicated that LYC alleviated D-gal induced cognitive impairments. LYC ameliorated brain ageing by decreasing the number of SA-β-gal- stained neurons, downregulating the protein expression of the cellular senescence associated genes P19/P21/P53, increasing the activities of the antioxidant enzymes GSH and SOD, downregulating the level of ROS, inhibiting the activation of MAPKs signalling and downregulating the levels of the inflammatory cytokines IL-1β and TNFɑ in mouse brains. LYC ameliorated synaptic dysfunction by increasing the expression of the neurotrophic factor BDNF and synaptic proteins. Moreover, LYC attenuated D-gal-induced mitochondrial morphological damage, and promoted the expression of mitochondrial functional proteins. LYC also promoted insulin signal transduction in mouse brains through the regulation of IRS-1/AKT/GSK3β signalling.

Mechanisms of ovarian aging in women: a review

Ovarian aging is a natural and physiological aging process characterized by loss of quantity and quality of oocyte or follicular pool. As it is generally accepted that women are born with a finite follicle pool that will go through constant decline without renewing, which, together with decreased oocyte quality, makes a severe situation for women who is of advanced age but desperate for a healthy baby. The aim of our review was to investigate mechanisms leading to ovarian aging by discussing both extra- and intra- ovarian factors and to identify genetic characteristics of ovarian aging. The mechanisms were identified as both extra-ovarian alternation of hypothalamic-pituitary-ovarian axis and intra-ovarian alternation of ovary itself, including telomere, mitochondria, oxidative stress, DNA damage, protein homeostasis, aneuploidy, apoptosis and autophagy. Moreover, here we reviewed related Genome-wide association studies (GWAS studies) from 2009 to 2021 and next generation sequencing (NGS) studies of primary ovarian insufficiency (POI) in order to describe genetic characteristics of ovarian aging. It is reasonable to wish more reliable anti-aging interventions for ovarian aging as the exploration of mechanisms and genetics being progressing.

The ginsenoside Rh2 protects porcine oocytes against aging and oxidative stress by regulating SIRT1 expression and mitochondrial activity

Post-ovulatory aging, a major problem faced by oocytes cultured in vitro, causes oxidative damage and mitochondrial dysfunction in oocytes. The ginsenoside Rh2 is one of the main monomeric components of ginseng, but its effects on porcine oocytes are unknown. In the present study, in vitro aging (IVA) and accelerated induction of aging using H₂O₂ resulted in DNA damage and an increased incidence of abnormal spindle formation in porcine oocytes. Rh2 supplementation increased the antioxidant capacity, reduced the occurrence of early apoptosis, and improved the development of in vitro fertilized blastocysts. It also rescued the abnormal aggregation of mitochondria and the decrease of the mitochondrial membrane potential under mitochondrial dysfunction. Meanwhile, Rh2 enhanced mRNA expression of the anti-aging and mitochondrial biogenesis-related genes silent information regulator of transcription 1 (SIRT1) and peroxisome proliferator-activated receptor coactivator 1-α (PGC-1α), and the antioxidant gene superoxide dismutase 1 (SOD1). The protection of porcine oocytes against aging and oxidative stress by Rh2 was confirmed using the SIRT1-specific inhibitor EX-527. Our results reveal that Rh2 upregulates SIRT1/PGC-1α to enhance mitochondrial function in porcine oocytes and improve their quality. Our study indicates that Rh2 can be used to prevent mitochondrial dysfunction in oocytes.

H3K4 Methylation Promotes Expression of Mitochondrial Dynamics Regulators to Ensure Oocyte Quality in Mice

Significantly decreased H3K4 methylation in oocytes from aged mice indicates the important roles of H3K4 methylation in female reproduction. However, how H3K4 methylation regulates oocyte development remains largely unexplored. In this study, it is demonstrated that oocyte-specific expression of dominant negative mutant H3.3-K4M led to a decrease of the level of H3K4 methylation in mouse oocytes, resulting in reduced transcriptional activity and increased DNA methylation in oocytes, disturbed oocyte developmental potency, and fertility of female mice. The impaired expression of genes regulating mitochondrial functions in H3.3-K4M oocytes, accompanied by mitochondrial abnormalities, is further noticed. Moreover, early embryos from H3.3-K4M oocytes show developmental arrest and reduced zygotic genome activation. Collectively, these results show that H3K4 methylation in oocytes is critical to orchestrating gene expression profile, driving the oocyte developmental program, and ensuring oocyte quality. This study also improves understanding of how histone modifications regulate organelle dynamics in oocytes.

Aging-Related Ovarian Failure and Infertility: Melatonin to the Rescue

Aging has a major detrimental effect on the optimal function of the ovary with changes in this organ preceding the age-related deterioration in other tissues, with the middle-aged shutdown leading to infertility. Reduced fertility and consequent inability to conceive by women in present-day societies who choose to have children later in life leads to increased frustration. Melatonin is known to have anti-aging properties related to its antioxidant and anti-inflammatory actions. Its higher follicular fluid levels relative to blood concentrations and its likely synthesis in the oocyte, granulosa, and luteal cells suggest that it is optimally positioned to interfere with age-associated deterioration of the ovary. Additionally, the end of the female reproductive span coincides with a significant reduction in endogenous melatonin levels. Thus, the aims are to review the literature indicating melatonin production in mitochondria of oocytes, granulosa cells, and luteal cells, identify the multiple processes underlying changes in the ovary, especially late in the cessation of the reproductive life span, summarize the physiological and molecular actions of melatonin in the maintenance of normal ovaries and in the aging ovaries, and integrate the acquired information into an explanation for considering melatonin in the treatment of age-related infertility. Use of supplemental melatonin may help preserve fertility later in life and alleviate frustration in women delaying childbearing age, reduce the necessity of in vitro fertilization–embryo transfer (IVF-ET) procedures, and help solve the progressively increasing problem of non-aging-related infertility in women throughout their reproductive life span. While additional research is needed to fully understand the effects of melatonin supplementation on potentially enhancing fertility, studies published to date suggest it may be a promising option for those struggling with infertility.

mtUPR Modulation as a Therapeutic Target for Primary and Secondary Mitochondrial Diseases

Mitochondrial dysfunction is a key pathological event in many diseases. Its role in energy production, calcium homeostasis, apoptosis regulation, and reactive oxygen species (ROS) balance render mitochondria essential for cell survival and fitness. However, there are no effective treatments for most primary and secondary mitochondrial diseases to this day. Therefore, new therapeutic approaches, such as the modulation of the mitochondrial unfolded protein response (mtUPR), are being explored. mtUPRs englobe several compensatory processes related to proteostasis and antioxidant system mechanisms. mtUPR activation, through an overcompensation for mild intracellular stress, promotes cell homeostasis and improves lifespan and disease alterations in biological models of mitochondrial dysfunction in age-related diseases, cardiopathies, metabolic disorders, and primary mitochondrial diseases. Although mtUPR activation is a promising therapeutic option for many pathological conditions, its activation could promote tumor progression in cancer patients, and its overactivation could lead to non-desired side effects, such as the increased heteroplasmy of mitochondrial DNA mutations. In this review, we present the most recent data about mtUPR modulation as a therapeutic approach, its role in diseases, and its potential negative consequences in specific pathological situations.

Single-cell RNA-sequencing of retrieved human oocytes and eggs in clinical practice and for human ovarian cell atlasing

With the advancement of single-cell separation techniques and high-throughput sequencing platforms, single-cell RNA-sequencing (scRNA-seq) has emerged as a vital technology for understanding tissue and organ systems at cellular resolution. Through transcriptional analysis, it is possible to characterize unique or rare cell types, interpret their interactions, and reveal novel functional states or shifts in developmental stages. As such, this technology is uniquely suited for studying the cells within the human ovary. The ovary is a cellularly heterogeneous organ that houses follicles, the reproductive and endocrine unit that consists of an oocyte surrounded by hormone-producing support cells, as well as many other cell populations constituting stroma, vasculature, lymphatic, and immune components. Here we review studies that have utilized scRNA-seq technology to analyze cells from healthy human ovaries and discuss the single-cell isolation techniques used. We identified two overarching applications for scRNA-seq in the human ovary. The first applies this technology to investigate transcriptional differences in oocytes/eggs from patients undergoing in vitro fertilization treatments to ultimately improve clinical outcomes. The second utilizes scRNA-seq for the pursuit of creating a comprehensive single-cell atlas of the human ovary. The knowledge gained from these studies underscores the importance of scRNA-seq technologies in unlocking a new biological understanding of the human ovary.

Stem Cell-Based Therapeutic Strategies for Premature Ovarian Insufficiency and Infertility: A Focus on Aging

Reproductive aging is on the rise globally and inseparable from the entire aging process. An extreme form of reproductive aging is premature ovarian insufficiency (POI), which to date has mostly been of idiopathic etiology, thus hampering further clinical applications and associated with enormous socioeconomic and personal costs. In the field of reproduction, the important functional role of inflammation-induced ovarian deterioration and therapeutic strategies to prevent ovarian aging and increase its function are current research hotspots. This review discusses the general pathophysiology and relative causes of POI and comprehensively describes the association between the aging features of POI and infertility. Next, various preclinical studies of stem cell therapies with potential for POI treatment and their molecular mechanisms are described, with particular emphasis on the use of human induced pluripotent stem cell (hiPSC) technology in the current scenario. Finally, the progress made in the development of hiPSC technology as a POI research tool for engineering more mature and functional organoids suitable as an alternative therapy to restore infertility provides new insights into therapeutic vulnerability, and perspectives on this exciting research on stem cells and the derived exosomes towards more effective POI diagnosis and treatment are also discussed.

Construction of a mitochondrial dysfunction related signature of diagnosed model to obstructive sleep apnea

Background: The molecular mechanisms underlying obstructive sleep apnea (OSA) and its comorbidities may involve mitochondrial dysfunction. However, very little is known about the relationships between mitochondrial dysfunction-related genes and OSA. Methods: Mitochondrial dysfunction-related differentially expressed genes (DEGs) between OSA and control adipose tissue samples were identified using data from the Gene Expression Omnibus database and information on mitochondrial dysfunction-related genes from the GeneCards database. A mitochondrial dysfunction-related signature of diagnostic model was established using least absolute shrinkage and selection operator Cox regression and then verified. Additionally, consensus clustering algorithms were used to conduct an unsupervised cluster analysis. A protein-protein interaction network of the DEGs between the mitochondrial dysfunction-related clusters was constructed using STRING database and the hub genes were identified. Functional analyses, including Gene Ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, gene set enrichment analysis (GSEA), and gene set variation analysis (GSVA), were conducted to explore the mechanisms involved in mitochondrial dysfunction in OSA. Immune cell infiltration analyses were conducted using CIBERSORT and single-sample GSEA (ssGSEA). Results: we established mitochondrial dysfunction related four-gene signature of diagnostic model consisted of NPR3, PDIA3, SLPI, ERAP2, and which could easily distinguish between OSA patients and controls. In addition, based on mitochondrial dysfunction-related gene expression, we identified two clusters among all the samples and three clusters among the OSA samples. A total of 10 hub genes were selected from the PPI network of DEGs between the two mitochondrial dysfunction-related clusters. There were correlations between the 10 hub genes and the 4 diagnostic genes. Enrichment analyses suggested that autophagy, inflammation pathways, and immune pathways are crucial in mitochondrial dysfunction in OSA. Plasma cells and M0 and M1 macrophages were significantly different between the OSA and control samples, while several immune cell types, especially T cells (γ/δ T cells, natural killer T cells, regulatory T cells, and type 17 T helper cells), were significantly different among mitochondrial dysfunction-related clusters of OSA samples. Conclusion: A novel mitochondrial dysfunction-related four-gen signature of diagnostic model was built. The genes are potential biomarkers for OSA and may play important roles in the development of OSA complications.

Sirt3 deficiency accelerates ovarian senescence without affecting spermatogenesis in aging mice

Sirtuin-3 (SIRT3), the main deacetylase in the mitochondria, maintains cellular energy metabolism and redox balance by deacetylating mitochondrial proteins in a NAD⁺-dependent manner. Growing evidence indicates that decreased Sirt3 expression is involved in various age-related maladies. However, the role of Sirt3 in ovarian and testicular senescence remains unclear. In this study, we observed that sirt3 expression showed age-dependent decreases in the ovary but not the testis. We generated Sirt3 null mice via CRISPR/Cas9-mediated genome editing. We observed that Sirt3 deletion accelerated ovarian aging, as shown by a decrease in offspring sizes, the follicle reserve and oocytes markers (Bmp15 and Gdf9) as well as increased expression of aging and inflammation-related genes (p16, p21, Il-1α, and Il-1β). Sirt3 deficiency led to an accumulation of superoxide and disruption of spindle assembly accompanied by mitochondrial dysfunction (uneven mitochondria distribution, decreased mitochondrial potential as well as reduced mitochondrial DNA content) in aging oocytes. Meanwhile, in ovaries of Sirt3 null mice, the impaired mitochondrial functions were shown by decreases in mitochondrial respiratory complexes, along with lower levels of mitochondrial fusion (OPA1, MFN2) and fission (DRP1, FIS1) proteins. er levels of mitochondrial fusion (OPA1, MFN2) and fission (DRP1, FIS1) proteins. Interestingly, Sirt3^-/- male mice exhibited no changes on the testicular histology, serum testosterone levels, germ-cell proliferation, and differentiation of spermatogonia. Meiotic prophase I spermatocytes were also normal. Levels of superoxide, mitochondrial potential as well as expression of mitochondrially-encoded genes were unaltered in Sirt3^-/- testes. Collectively, the results indicated that SIRT3 plays a critical role in maintaining the ovarian follicle reserve and oocyte quality in aging mice, suggesting its important role in controlling ovarian senescence.

Age-related changes in Folliculogenesis and potential modifiers to improve fertility outcomes - A narrative review

Reproductive aging is characterized by a decline in oocyte quantity and quality, which is directly associated with a decline in reproductive potential, as well as poorer reproductive success and obstetrical outcomes. As women delay childbearing, understanding the mechanisms of ovarian aging and follicular depletion have become increasingly more relevant. Age-related meiotic errors in oocytes are well established. In addition, it is also important to understand how intraovarian regulators change with aging and how certain treatments can mitigate the impact of aging. Individual studies have demonstrated that reproductive pathways involving antimullerian hormone (AMH), vascular endothelial growth factor (VEGF), neurotropins, insulin-like growth factor 1 (IGF1), and mitochondrial function are pivotal for healthy oocyte and cumulus cell development and are altered with increasing age. We provide a comprehensive review of these individual studies and explain how these factors change in oocytes, cumulus cells, and follicular fluid. We also summarize how modifiers of folliculogenesis, such as vitamin D, coenzyme Q, and dehydroepiandrosterone (DHEA) may be used to potentially overcome age-related changes and enhance fertility outcomes of aged follicles, as evidenced by human and rodent studies.

Tiron Has Negative Effects on Osteogenic Differentiation via Mitochondrial Dysfunction in Human Periosteum-Derived Cells

Tiron is a potent antioxidant that counters the pathological effects of reactive oxygen species (ROS) production due to oxidative stress in various cell types. We examined the effects of tiron on mitochondrial function and osteoblastic differentiation in human periosteum-derived cells (hPDCs). Tiron increased mitochondrial activity and decreased senescence-associated β-galactosidase activity in hPDCs; however, it had a detrimental effect on osteoblastic differentiation by reducing alkaline phosphatase (ALP) activity and alizarin red-positive mineralization, regardless of H₂O₂ treatment. Osteoblast-differentiating hPDCs displayed increased ROS production compared with non-differentiating hPDCs, and treatment with tiron reduced ROS production in the differentiating cells. Antioxidants decreased the rates of oxygen consumption and ATP production, which are increased in hPDCs during osteoblastic differentiation. In addition, treatment with tiron reduced the levels of most mitochondrial proteins, which are increased in hPDCs during culture in osteogenic induction medium. These results suggest that tiron exerts negative effects on the osteoblastic differentiation of hPDCs by causing mitochondrial dysfunction.

The role of oxidative stress in ovarian aging: a review

Ovarian aging refers to the process by which ovarian function declines until eventual failure. The pathogenesis of ovarian aging is complex and diverse; oxidative stress (OS) is considered to be a key factor. This review focuses on the fact that OS status accelerates the ovarian aging process by promoting apoptosis, inflammation, mitochondrial damage, telomere shortening and biomacromolecular damage. Current evidence suggests that aging, smoking, high-sugar diets, pressure, superovulation, chemotherapeutic agents and industrial pollutants can be factors that accelerate ovarian aging by exacerbating OS status. In addition, we review the role of nuclear factor E2-related factor 2 (Nrf2), Sirtuin (Sirt), mitogen-activated protein kinase (MAPK), protein kinase B (AKT), Forkhead box O (FoxO) and Klotho signaling pathways during the process of ovarian aging. We also explore the role of antioxidant therapies such as melatonin, vitamins, stem cell therapies, antioxidant monomers and Traditional Chinese Medicine (TCM), and investigate the roles of these supplements with respect to the reduction of OS and the improvement of ovarian function. This review provides a rationale for antioxidant therapy to improve ovarian aging.

Biomaterials and advanced technologies for the evaluation and treatment of ovarian aging

Ovarian aging is characterized by a progressive decline in ovarian function. With the increase in life expectancy worldwide, ovarian aging has gradually become a key health problem among women. Over the years, various strategies have been developed to preserve fertility in women, while there are currently no clinical treatments to delay ovarian aging. Recently, advances in biomaterials and technologies, such as three-dimensional (3D) printing and microfluidics for the encapsulation of follicles and nanoparticles as delivery systems for drugs, have shown potential to be translational strategies for ovarian aging. This review introduces the research progress on the mechanisms underlying ovarian aging, and summarizes the current state of biomaterials in the evaluation and treatment of ovarian aging, including safety, potential applications, future directions and difficulties in translation.

Ppan is essential for preimplantation development in mice†

PETER PAN (PPAN), located to nucleoli and mitochondria, is a member of the Brix domain protein family, involved in rRNA processing through its rRNA binding motif and mitochondrial apoptosis by protecting mitochondria structure and suppressing basal autophagic flux. Ppan is important for cell proliferation and viability, and mutation of Ppan in Drosophila caused larval lethality and oogenesis failure. Yet, its role in mammalian reproduction remains unclear. In this study, we explored the function of Ppan in oocyte maturation and early embryogenesis using conditional knockout mouse model. Deficiency of maternal Ppan significantly downregulated the expression level of 5.8S rRNA, 18S rRNA, and 28S rRNA, though it had no effect on oocyte maturation or preimplantation embryo development. However, depletion of both maternal and zygotic Ppan blocked embryonic development at morula stage. Similar phenotype was obtained when only zygotic Ppan was depleted. We further identified no DNA binding activity of PPAN in mouse embryonic stem cells, and depletion of Ppan had minimum impact on transcriptome but decreased expression of 5.8S rRNA, 18S rRNA, and 28S rRNA nevertheless. Our findings demonstrate that Ppan is indispensable for early embryogenesis in mice.

Epitalon protects against post-ovulatory aging-related damage of mouse oocytes in vitro

The developmental potential of oocytes decreases with time after ovulation in vivo or in vitro. Epitalon is a synthetic short peptide made of four amino acids (alanine, glutamic acid, aspartic acid, and glycine), based on a natural peptide called epithalamion extracted from the pineal gland. It is a potent antioxidant, comparable to melatonin, that may confer longevity benefits. The current study aims to test the protective effects of Epitalon on the quality of post-ovulatory aging oocytes. Epitalon at 0.1mM was added to the culture medium, and the quality of oocytes was evaluated at 6h, 12h, and 24h of culture. We found that 0.1mM Epitalon reduced intracellular reactive oxygen species. Epitalon treatment significantly decreased frequency of spindle defects and abnormal distribution of cortical granules during aging for 12h and 24h, while increased mitochondrial membrane potential and DNA copy number of mitochondria, thus decreasing apoptosis of oocytes by 24h of in vitro aging. Our results suggest that Epitalon can delay the aging process of oocytes in vitro via modulating mitochondrial activity and ROS levels.

Procyanidin B2 Protects Aged Oocytes Against Meiotic Defects Through Cortical Tension Modulation

Defects in meiotic process are the main factors responsible for the decreased developmental competence in aged oocytes. Our recent research indicated that natural antioxidant procyanidin B2 (PCB2) promoted maturation progress in oocytes from diabetic mice. However, the effect of PCB2 on aging-induced chromosome abnormalities and the underlying mechanism have not been explored. Here, we found that PCB2 recovered aging-caused developmental arrest during meiotic maturation, germinal vesicle breakdown (GVBD) rate was significantly higher in aged oocytes treated with PCB2 (P < 0.05). Furthermore, we discovered that cortical mechanics were altered during aging process, cortical tension-related proteins were aberrantly expressed in aged oocytes (P < 0.001). PCB2 supplementation efficaciously antagonized aging-induced decreased cortical tension (P < 0.001). Moreover, PCB2 restored spindle morphology (P < 0.01), maintained proper chromosome alignment (P < 0.05), and dramatically reduced reactive oxygen species (ROS) level (P < 0.05) in aged oocytes. Collectively, our results reveal that PCB2 supplementation is a feasible approach to protect oocytes from reproductive aging, contributing to the improvement of oocytes quality.

Ovarian reserve parameters and IVF outcomes in 510 women with poor ovarian response (POR) treated with intraovarian injection of autologous platelet rich plasma (PRP)

The aim of the current study was to characterize ovarian reserve parameters and IVF outcomes in women with a history of poor ovarian response (POR) treated with intraovarian injection of autologous platelet rich plasma (PRP). Reproductive age women (N=510; age range 30-45yo) diagnosed with POR based on Poseidon criteria were included in the study. PRP treatment resulted in higher AFC, higher serum AMH, lower serum FSH, and a higher number of mature oocytes and cleavage and blastocyst stage embryos. After PRP injection, 22 women (4.3%) conceived spontaneously, 14 (2.7%) were lost to follow up, and 474 (92.9%) attempted IVF. Among women who attempted IVF, 312 (65.8%) generated embryos and underwent embryo transfer, 83 (17.5%) achieved a pregnancy, and 54 (11.4%) achieved sustained implantation/live birth (SI/LB). In total, of the 510 women with POR and mean age of 40.3, PRP resulted in improvement of ovarian reserve parameters, a pregnancy rate of 20.5% and SI/LB rate of 12.9%. Our findings suggest that PRP treatment may be considered in women with POR. For wider clinical application, its clinical efficacy will need to be demonstrated in prospective randomized clinical trials.

Therapeutic options for premature ovarian insufficiency: an updated review

Primary ovarian insufficiency (POI) is a rare gynecological condition. This disease causes menstrual disturbances, infertility, and various health problems. Historically, hormone replacement therapy is the first-line treatment for this disorder. Women diagnosed with POI are left with limited therapeutic options. In order to remedy this situation, a new generation of therapeutic approaches, such as in vitro activation, mitochondrial activation technique, stem cell and exosomes therapy, biomaterials strategies, and platelet-rich plasma intra-ovarian infusion, is being developed. However, these emerging therapies are yet in the experimental stage and require precise design components to accelerate their conversion into clinical treatments. Thus, each medical practitioner bears responsibility for selecting suitable therapies for individual patients. In this article, we provide a timely analysis of the therapeutic strategies that are available for POI patients and discuss the prospects of POI therapy.

A combination containing natural extracts of clove, Sophora flower bud, and yam improves fertility in aged female mice via multiple mechanisms

INTRODUCTION

With society development, the age at which women choose to have children has been gradually delayed. To improve the reduced fertility in women at advanced maternal age, we developed a combination containing natural extracts from clove, Sophora flower bud and Chinese yam with a mass ratio 15:6:10 and named it as DACHAO.

METHODS AND RESULTS

We then gavage DACHAO at a dose of 310 mg/kg BW to female mice at 10 month of age and investigated its effects on ovarian functions. Using MitoTracker probes, ROS, and JC-1 staining, we found that DACHAO treatment improved mitochondria functions in oocytes from aged mice. We also observed increased blastocyst formation when mature oocytes from control and DACHAO treated mice were for IVF and in vitro embryo culture. Cell counting and TUNEL assay further revealed increased cell numbers and decreased apoptosis in blastocysts of DACHAO group. After control or DACHAO treated mice being mated with fertile male mice, fertility test revealed a greater first litter size in the DACHAO group. Further studies demonstrated that DACHAO treatment could alleviate the retarded ovarian function in aged mice via changes in serum hormone levels, over-expression of antioxidant factors, under-expression of inflammation-related factors, and reduced apoptosis in the ovaries.

DISCUSSION

Thus, the new combination DACHAO will be a good choice in clinic to improve ovarian functions for women at advanced maternal age.