The spatio-temporal dynamics of mitochondrial membrane potential during oocyte maturation

Rutin enhances mitochondrial function and improves the developmental potential of vitrified ovine GV-stage oocyte

Vitrification of oocyte has become an important component of assisted reproductive technology and has important implications for animal reproduction and the preservation of biodiversity. However, vitrification adversely affects mitochondrial function and oocyte developmental potential, mainly because of oxidative damage. Rutin is a highly effective antioxidant, but no information is available to the effect of rutin on the mitochondrial function and development in vitrified oocytes. Therefore, we studied the effects of rutin supplementation of vitrification solution on mitochondrial function and developmental competence of ovine germinal vesicle (GV) stage oocytes post vitrification. The results showed that supplementation of vitrification solution with 0.6 mM rutin significantly increased the cleavage rate (71.6 % vs. 59.3 %) and blastocyst rate (18.9 % vs. 6.8 %) compared to GV-stage oocytes in the vitrified group. Then, we analyzed the reactive oxygen species (ROS), glutathione (GSH), mitochondrial activity and membrane potential (ΔΨm), endoplasmic reticulum (ER) Ca2+, and annexin V (AV) of vitrified sheep GV-stage oocytes. Vitrified sheep oocytes exhibited increased levels of ROS and Ca2+, higher rate of AV-positive oocytes, and decreased mitochondrial activity, GSH and ΔΨm levels. However, rutin supplementation in vitrification solution decreased the levels of ROS, Ca2+ and AV-positive oocytes rate, and increased the GSH and ΔΨm levels in vitrified oocytes. Results revealed that rutin restored mitochondrial function, regulated Ca2+ homeostasis and decreased apoptosis potentially caused by mitophagy in oocytes. To understand the mechanism of rutin functions in vitrified GV-stage oocytes in sheep, we analyzed the transcriptome and found that rutin mediated oocytes development and mitochondrial function, mainly by affecting oxidative phosphorylation and the mitophagy pathways. In conclusion, supplementing with 0.6 mM rutin in vitrification solution significantly enhanced developmental potential through improving mitochondrial function and decreased apoptosis potentially caused by mitophagy after vitrification of ovine GV-stage oocytes.

PKD regulates mitophagy to prevent oxidative stress and mitochondrial dysfunction during mouse oocyte maturation

Mitochondria play dominant roles in various cellular processes such as energy production, apoptosis, calcium homeostasis, and oxidation-reduction balance. Maintaining mitochondrial quality through mitophagy is essential, especially as its impairment leads to the accumulation of dysfunctional mitochondria in aging oocytes. Our previous research revealed that PKD expression decreases in aging oocytes, and its inhibition negatively impacts oocyte quality. Given PKD's role in autophagy mechanisms, this study investigates whether PKD regulates mitophagy to maintain mitochondrial function and support oocyte maturation. When fully grown oocytes were treated with CID755673, a potent PKD inhibitor, we observed meiosis arrest at the metaphase I stage, along with decreased spindle stability. Our results demonstrate an association with mitochondrial dysfunction, including reduced ATP production and fluctuations in Ca2+ homeostasis, which ultimately lead to increased ROS accumulation, stimulating oxidative stress-induced apoptosis and DNA damage. Further research has revealed that these phenomena result from PKD inhibition, which affects the phosphorylation of ULK, thereby reducing autophagy levels. Additionally, PKD inhibition leads to decreased Parkin expression, which directly and negatively affects mitophagy. These defects result in the accumulation of damaged mitochondria in oocytes, which is the primary cause of mitochondrial dysfunction. Taken together, these findings suggest that PKD regulates mitophagy to support mitochondrial function and mouse oocyte maturation, offering insights into potential targets for improving oocyte quality and addressing mitochondrial-related diseases in aging females.

Melatonin mitigates PNMC-induced disruption of spindle assembly and mitochondrial function in mouse Oocytes

3-methyl-4-nitrophenol (PNMC), a degradation product of organophosphorus insecticides and a byproduct of fuel combustion, exerting endocrine-disrupting effects. However, its impact on the meiotic process of oocytes remains unclear. In the present study, we investigated the effects of PNMC on meiotic maturation of mouse oocytes in vitro and related mechanisms. Morphologically, PNMC-exposure affected germinal vesicle breakdown (GVBD) and polar body extrusion (PBE) in mouse oocytes. Proteomic analysis suggested that PNMC-exposure altered oocyte protein expression that are associated with cytoskeleton, mitochondrial function and oxidative stress. Further studies demonstrated that PNMC-exposure disrupted spindle assembly and chromosome alignment, caused sustained activation of spindle assembly checkpoint (SAC), and arrested meiosis in oocytes. Specifically, PNMC-exposure interfered with the function of microtubule organizing centers (MTOCs) by significantly reducing phosphorylated mitogen activated protein kinase (p-MAPK) expression and disrupting the localization of Pericentrin and p-Aurora A, leading to spindle assembly failure. Besides, PNMC-exposure also increased α-tubulin acetylation, decreased microtubule stability. Moreover, PNMC-exposure impaired mitochondrial function, evidenced by abnormal mitochondrial distribution, decreased mitochondrial membrane potential and ATP levels, release of Cytochrome C into the cytoplasm, and elevated ROS levels. As a result, exposure to PNMC caused DNA damage and early apoptosis in oocytes. Fortunately, melatonin was able to promote oocyte maturation by removing the excessive ROS and enhancing mitochondrial function. These results highlight the adverse effects of PNMC on meiotic maturation, and underscore the protective role of melatonin against PNMC-induced damage.

Rejuvenation of aged oocyte through exposure to young follicular microenvironment

Reproductive aging is a major cause of fertility decline, attributed to decreased oocyte quantity and developmental potential. A possible cause is aging of the surrounding follicular somatic cells that support oocyte growth and development by providing nutrients and regulatory factors. Here, by creating chimeric follicles, whereby an oocyte from one follicle was transplanted into and cultured within another follicle whose native oocyte was removed, we show that young oocytes cultured in aged follicles exhibited impeded meiotic maturation and developmental potential, whereas aged oocytes cultured within young follicles were significantly improved in rates of maturation, blastocyst formation and live birth after in vitro fertilization and embryo implantation. This rejuvenation of aged oocytes was associated with enhanced interaction with somatic cells, transcriptomic and metabolomic remodeling, improved mitochondrial function and higher fidelity of meiotic chromosome segregation. These findings provide the basis for a future follicular somatic cell-based therapy to treat female infertility.

ONC206 targeting ClpP induces mitochondrial dysfunction and protective autophagy in hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is the most common form of liver cancer, accounting for approximately 90 % of all cases. ONC201, a member of the imipridone drug family, has shown promising therapeutic potential and a good safety profile in both malignant pediatric central nervous system tumors (diffuse midline glioma [DMG]) and hematologic malignancies. ONC206 is a more potent analog of ONC201. However, the ONC206 potential and mechanism of action in HCC remain to be elucidated. We found that ONC206 hindered HCC growth by suppressing cell proliferation and inducing apoptosis. Moreover, ONC206 induced cytoprotective autophagy, and blocking autophagy enhanced the proapoptotic effect of ONC206. Additionally, ONC206 induced mitochondrial swelling, reduced the mitochondrial membrane potential (MMP), and led to the accumulation of mitochondrial ROS in HCC cells, ultimately resulting in mitochondrial dysfunction. The HCC patient samples exhibited notably elevated levels of caseinolytic protease proteolytic subunit (ClpP), which serves as a mediator of ONC206-induced mitochondrial dysfunction and the activation of protective autophagy. knockdown of ClpP reversed the cytotoxic effects of ONC206 on HCC cells. In summary, our results provide the first insight into the mechanism by which ONC206 exerts its anti-HCC effects and induces protective autophagy in HCC cells through ClpP.

Reproductive Ageing: Metabolic contribution to age-related chromosome missegregation in mammalian oocytes

In brief

Chromosome missegregation and declining energy metabolism are considered to be unrelated features of oocyte ageing that contribute to poor reproductive outcomes. Given the bioenergetic cost of chromosome segregation, we propose here that altered energy metabolism during ageing may be an underlying cause of age-related chromosome missegregation and aneuploidy.

Abstract

Advanced reproductive age in women is a major cause of infertility, miscarriage and congenital abnormalities. This is principally caused by a decrease in oocyte quality and developmental competence with age. Oocyte ageing is characterised by an increase in chromosome missegregation and aneuploidy. However, the underlying mechanisms of age-related aneuploidy have not been fully elucidated and are still under active investigation. In addition to chromosome missegregation, oocyte ageing is also accompanied by metabolic dysfunction. In this review, we integrate old and new perspectives on oocyte ageing, chromosome segregation and metabolism in mammalian oocytes and make direct links between these processes. We consider age-related alterations to chromosome segregation machinery, including the loss of cohesion, microtubule stability and the integrity of the spindle assembly checkpoint. We focus on how metabolic dysfunction in the ageing oocyte disrupts chromosome segregation machinery to contribute to and exacerbate age-related aneuploidy. More specifically, we discuss how mitochondrial function, ATP production and the generation of free radicals are altered during ageing. We also explore recent developments in oocyte metabolic ageing, including altered redox reactions (NAD+ metabolism) and the interactions between oocytes and their somatic nurse cells. Throughout the review, we integrate the mechanisms by which changes in oocyte metabolism influence age-related chromosome missegregation.

Conditional loss of Brca1 in oocytes causes reduced litter size, ovarian reserve depletion and impaired oocyte in vitro maturation with advanced reproductive age in mice

BACKGROUND

An estimated 1 in 350 women carry germline BRCA1/2 mutations, which confer an increased risk of developing breast and ovarian cancer, and may also contribute to subfertility. All mature, sex steroid-producing ovarian follicles are drawn from the pool of non-renewable primordial follicles, termed the 'ovarian reserve'. The clinical implications of early ovarian reserve exhaustion extend beyond infertility, to include the long-term adverse health consequences of loss of endocrine function and premature menopause. We aimed to determine whether conditional loss of Brca1 in oocytes impacts ovarian follicle numbers, oocyte quality and fertility in mice with advancing maternal age. We also aimed to determine the utility of AMH as a marker of ovarian function, by assessing circulating AMH levels in mice and women with BRCA1/2 mutations, and correlating this with ovarian follicle counts.

METHODS

In this study, we addressed a longstanding question in the field regarding the functional consequences of BRCA1 inactivation in oocytes. To recapitulate loss of BRCA1 protein function in oocytes, we generated mice with conditional gene deletion of Brca1 in oocytes using Gdf9-Cre recombinase (WT: Brca1fl/flGdf9+/+; cKO: Brca1fl/flGdf9cre/+).

FINDINGS

While the length of the fertile lifespan was not altered between groups after a comprehensive breeding trial, conditional loss of Brca1 in oocytes led to reduced litter size in female mice. Brca1 cKO animals had a reduced ovarian reserve and oocyte maturation was impaired with advanced maternal age at postnatal day (PN)300, compared to WT animals. Serum anti-Müllerian hormone (AMH) concentrations (the gold-standard indirect marker of the ovarian reserve used in clinical practice) were not predictive of reduced primordial follicle number in Brca1 cKO mice versus WT. Furthermore, we found no correlation between follicle number or density and serum AMH concentrations in matched samples from a small cohort of premenopausal women with BRCA1/2 mutations.

INTERPRETATION

Together, our data demonstrate that BRCA1 is a key regulator of oocyte number and quality in females and suggest that caution should be used in relying on AMH as a reliable marker of the ovarian reserve in this context.

FUNDING

This work was made possible through Victorian State Government Operational Infrastructure Support and Australian Government NHMRC IRIISS. This work was supported by funding from the Australian Research Council (ALW - DE21010037 and KJH - FT190100265), as well as the National Breast Cancer Foundation (IIRS-22-092) awarded to ALW and KJH. LRA, YML, LT, EOKS and MG were supported by Australian Government Research Training Program Scholarships. LRA, YML and LT were also supported by a Monash Graduate Excellence Scholarship. YC, SG and XC were supported by Monash Biomedicine Discovery Institute PhD Scholarships. LRA was also supported by a Monash University ECPF24-6809920940 Fellowship. JMS was supported by NHMRC funding (2011299). MH was supported by an NHMRC Investigator Grant (1193838).

Deficiency of ValRS-m Causes Male Infertility in Drosophila melanogaster

Drosophila spermatogenesis involves the renewal of germline stem cells, meiosis of spermatocytes, and morphological transformation of spermatids into mature sperm. We previously demonstrated that Ocnus (ocn) plays an essential role in spermatogenesis. The ValRS-m (Valyl-tRNA synthetase, mitochondrial) gene was down-regulated in ocn RNAi testes. Here, we found that ValRS-m-knockdown induced complete sterility in male flies. The depletion of ValRS-m blocked mitochondrial behavior and ATP synthesis, thus inhibiting the transition from spermatogonia to spermatocytes, and eventually, inducing the accumulation of spermatogonia during spermatogenesis. To understand the intrinsic reason for this, we further conducted transcriptome-sequencing analysis for control and ValRS-m-knockdown testes. The differentially expressed genes (DEGs) between these two groups were selected with a fold change of ≥2 or ≤1/2. Compared with the control group, 4725 genes were down-regulated (dDEGs) and 2985 genes were up-regulated (uDEGs) in the ValRS-m RNAi group. The dDEGs were mainly concentrated in the glycolytic pathway and pyruvate metabolic pathway, and the uDEGs were primarily related to ribosomal biogenesis. A total of 28 DEGs associated with mitochondria and 6 meiosis-related genes were verified to be suppressed when ValRS-m was deficient. Overall, these results suggest that ValRS-m plays a wide and vital role in mitochondrial behavior and spermatogonia differentiation in Drosophila.

An aggregated mitochondrial distribution in preimplantation embryos disrupts nuclear morphology, function, and developmental potential

A dispersed cytoplasmic distribution of mitochondria is a hallmark of normal cellular organization. Here, we have utilized the expression of exogenous Trak2 in mouse oocytes and embryos to disrupt the dispersed distribution of mitochondria by driving them into a large cytoplasmic aggregate. Our findings reveal that aggregated mitochondria have minimal impact on asymmetric meiotic cell divisions of the oocyte. In contrast, aggregated mitochondria during the first mitotic division result in daughter cells with unequal sizes and increased micronuclei. Further, in two-cell embryos, microtubule-mediated centering properties of the mitochondrial aggregate prevent nuclear centration, distort nuclear shape, and inhibit DNA synthesis and the onset of embryonic transcription. These findings demonstrate the motor protein-mediated distribution of mitochondria throughout the cytoplasm is highly regulated and is an essential feature of cytoplasmic organization to ensure optimal cell function.

YiQi GuBen capsule alleviates OVA-induced asthma through improving mitochondrial dysfunction

Objective: This study aims to explore the effect of YiQi GuBen capsule on improving mitochondrial dysfunction in an animal model of asthma.Methods: The mice (n = 8) were divided into four groups including control (NC), ovalbumin (OVA), dexamethasone (OVA + DEX), and YiQi GuBen (OVA + YQGB) groups. Firstly, we established an OVA-induced mouse asthma model except for the NC group, which then were treated with dexamethasone and YiQi GuBen capsule. Subsequently, HE staining and Masson staining were used for pathological analysis of mice lung tissues. Next, we used transmission electron microscopy (TEM) to observe the effect of the Yiqi Guben capsule on the ultrastructure of mitochondria. Flow cytometry was used to analyze the ROS level, membrane potential, and the number of mitochondria in lung tissue. Moreover, we analyzed the copy number of mitochondrial DNA (mtDNA) and the expression levels of activator peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) and mitochondrial transcription factor A (TFAM).Results: The results of the pathological analysis showed that after treatment with the YiQi GuBen capsule, the lung tissue damage was significantly reduced. In addition, we observed that the ultrastructural damage of mitochondria was improved. Flow cytometry proved that after treatment with the YiQi GuBen capsule, the level of ROS in the mitochondria was effectively reduced, while the mitochondrial membrane potential decreased and the number increased significantly. Moreover, we found that the copy number of mtDNA was significantly increased and the expression levels of PGC-1α and TFAM were significantly upgraded.Conclusion: This study suggests YiQi GuBen capsule can effectively improve mitochondrial dysfunction in the OVA-induced mouse model.

Ex ovo omnia-why don't we know more about egg quality via imaging?

Determining egg quality is the foremost challenge in assisted reproductive technology (ART). Although extensive advances have been made in multiple areas of ART over the last 40 years, oocyte quality assessment tools have not much evolved beyond standard morphological observation. The oocyte not only delivers half of the nuclear genetic material and all of the mitochondrial DNA to an embryo but also provides complete developmental support during embryonic growth. Oocyte mitochondrial numbers far exceed those of any somatic cell, yet little work has been done to evaluate the mitochondrial bioenergetics of an oocyte. Current standard oocyte assessment in in vitro fertilization (IVF) centers include the observation of oocytes and their surrounding cell complex (cumulus cells) via stereomicroscope or inverted microscope, which is largely primitive. Additional oocyte assessments include polar body grading and polarized light meiotic spindle imaging. However, the evidence regarding the aforementioned methods of oocyte quality assessment and IVF outcomes is contradictory and non-reproducible. High-resolution microscopy techniques have also been implemented in animal and human models with promising outcomes. The current era of oocyte imaging continues to evolve with discoveries in artificial intelligence models of oocyte morphology selection albeit at a slow rate. In this review, the past, current, and future oocyte imaging techniques will be examined with the goal of drawing attention to the gap which limits our ability to assess oocytes in real time. The implications of improved oocyte imaging techniques on patients undergoing IVF will be discussed as well as the need to develop point of care oocyte assessment testing in IVF labs.

Triphenyltin chloride exposure inhibits meiotic maturation of mouse oocytes by disrupting cytoskeleton assembly and cell cycle progression

Triphenyltin chloride (TPTCL) is widely used in various industrial and agricultural applications. This study aimed to elucidate the mechanisms underlying the toxicological effects of TPTCL on oocytes. The obtained findings revealed that TPTCL exposure reduced polar body extrusion (PBE) and induced meiotic arrest. Mechanistically, TPTCL disrupted meiotic spindle assembly and chromosome alignment. Further analysis indicated a significant decrease in p-MAPK expression, and disturbances in the localization of Pericentrin and p-Aurora A in TPTCL exposed oocytes, which suggesting impaired microtubule organizing center (MTOC)function. Moreover, TPTCL exposure enhance microtubule acetylation and microtubule instability. Therefore, the spindle assembly checkpoint (SAC) remained activated, and the activity of the anaphase-promoting complex (APC) was inhibited, thereby preventing oocytes from progressing into the entering anaphase I (AI) stage. TPTCL exposure also augmented the actin filaments in the cytoplasm. Notably, mitochondrial function appeared unaffected by TPTCL, as evidenced indicated by stable mitochondrial membrane potential and ATP content. Furthermore, TPTCL treatment altered H3K27me2, H3K27me3 and H3K9me3 levels, suggesting changes in epigenetic modifications in oocytes. Taken together, our results suggest that TPTCL disrupts cytoskeleton assembly, continuously activates SAC, inhibits APC activity, and blocks meiotic progression, ultimately impair oocyte maturation.

Intrauterine Infusion and Hysteroscopic Injection of Autologous Platelet-Rich Plasma for Patients with a Persistent Thin Endometrium: A Prospective Case-Control Study

Objectives: To evaluate the effect of intrauterine infusion and hysteroscopic injection of autologous platelet-rich plasma (PRP) in patients with a persistent thin endometrium (EM) undergoing euploid frozen embryo transfer (EFET) cycles. Methods: This prospective case-control study enrolled 116 infertile women with thin EM (<7 mm) who underwent hormone replacement therapy (HRT) for EFET. These women had experienced at least one previous unsuccessful EFET cycle, which either resulted in the cancellation of the cycle or failure of pregnancy. A total of 55 women received an intrauterine infusion of PRP before FET, 38 received a hysteroscopic injection of PRP, and 23 received standard HRT treatment without PRP (control group). Only euploid embryos were transferred in these cycles. The primary outcomes were the implantation rate (IR) and clinical pregnancy rate (CPR) after EFET. Results: After receiving intrauterine infusion and hysteroscopic injection of PRP, 78.2% and 55.3% of patients, respectively, showed an EM thickness exceeding 7 mm, followed by embryo transfer. The hysteroscopic injection group demonstrated significantly higher IR (52%), a higher trend of CPR (52%), and a higher live birth rate (38%) than the control group (18%, 22%, and 4%). Conclusions: Intrauterine infusion and hysteroscopic injection of autologous PRP may be effective methods to increase EM thickness in HRT cycles. According to our results, both methods could increase EM thickness, while hysteroscopic injection appeared to provide more significant assistance in increasing IR, CPR, and live birth rate after EFET in patients with persistent thin EM.

Spinning Disk Confocal Microscopy for Optimized and Quantified Live Imaging of 3D Mitochondrial Network

Mitochondria are the energy factories of a cell, and depending on the metabolic requirements, the mitochondrial morphology, quantity, and membrane potential in a cell change. These changes are frequently assessed using commercially available probes. In this study, we tested the suitability of three commercially available probes-namely 5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolo-carbocyanine iodide (JC-1), MitoTracker Red CMX Rox (CMXRos), and tetramethylrhodamine methyl ester (TMRM)-for assessing the mitochondrial quantity, morphology, and membrane potential in living human mesoangioblasts in 3D with confocal laser scanning microscope (CLSM) and scanning disk confocal microscope (SDCM). Using CLSM, JC-1, and CMXRos-but not TMRM-uncovered considerable background and variation. Using SDCM, the background signal only remained apparent for the JC-1 monomer. Repetitive imaging of CMXRos and JC-1-but not TMRM-demonstrated a 1.5-2-fold variation in signal intensity between cells using CLSM. The use of SDCM drastically reduced this variation. The slope of the relative signal intensity upon repetitive imaging using CLSM was lowest for TMRM (-0.03) and highest for CMXRos (0.16). Upon repetitive imaging using SDCM, the slope varied from 0 (CMXRos) to a maximum of -0.27 (JC-1 C1). Conclusively, our data show that TMRM staining outperformed JC-1 and CMXRos dyes in a (repetitive) 3D analysis of the entire mitochondrial quantity, morphology, and membrane potential in living cells.

Mitochondrial morphology, distribution and activity during oocyte development

Mitochondria have a crucial role in cellular function and exhibit remarkable plasticity, adjusting both their structure and activity to meet the changing energy demands of a cell. Oocytes, female germ cells that become eggs, undergo unique transformations: the extended dormancy period, followed by substantial increase in cell size and subsequent maturation involving the segregation of genetic material for the next generation, present distinct metabolic challenges necessitating varied mitochondrial adaptations. Recent findings in dormant oocytes challenged the established respiratory complex hierarchies and underscored the extent of mitochondrial plasticity in long-lived oocytes. In this review, we discuss mitochondrial adaptations observed during oocyte development across three vertebrate species (Xenopus, mouse, and human), emphasising current knowledge, acknowledging limitations, and outlining future research directions.

Mitochondrial Outer Membrane Translocase MoTom20 Modulates Mitochondrial Morphology and Is Important for Infectious Growth of the Rice Blast Fungus Magnaporthe oryzae

Mitochondria are highly dynamic organelles that constantly change their morphology to adapt to the cellular environment through fission and fusion, which is critical for a cell to maintain normal cellular functions. Despite the significance of this process in the development and pathogenicity of the rice blast fungus Magnaporthe oryzae, the underlying mechanism remains largely elusive. Here, we identified and characterized a mitochondrial outer membrane translocase, MoTom20, in M. oryzae. Targeted gene deletion revealed that MoTom20 plays an important role in vegetative growth, conidiogenesis, penetration, and infectious growth of M. oryzae. The growth rate, conidial production, appressorium turgor, and pathogenicity are decreased in the ΔMotom20 mutant compared with the wild-type and complemented strains. Further analysis revealed that MoTom20 localizes in mitochondrion and plays a key role in regulating mitochondrial fission and fusion balance, which is critical for infectious growth. Finally, we found that MoTom20 is involved in fatty-acid utilization, and its yeast homolog ScTom20 is able to rescue the defects of ΔMotom20 in mitochondrial morphology and pathogenicity. Overall, our data demonstrate that MoTom20 is a key regulator for mitochondrial morphology maintenance, which is important for infectious growth of the rice blast fungus M. oryzae. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Assessment of Mononuclear/Dinuclear copper acylhydrazone complexes for lung cancer treatment

Non-platinum metal-based complexes have good potential for cancer treatment. Here, we designed and synthesized five hydrazone copper(II) complexes, [Cu2(HL)2Cl2] 1A, [Cu2(HL)2(NO3)H2O]·NO3 2A, [Cu2(HL)2Br2] 3A, [Cu(L)pyridine] 1B and [Cu(HL)(pyridine)Br] 3B, and evaluated their anti-lung cancer activities. MTT experiments revealed that these copper(II) complexes exhibit higher anticancer activity than cisplatin. Mechanism studies revealed that complex 3A induced G1 phase cell cycle arrest, and induced cell apoptosis via reactive oxygen species (ROS)-mediated mitochondrial dysfunction. Scratch wound healing assay was also performed, revealing that complex 3A have good anti-cell migration activity. Hemolysis assays showed good blood biocompatibility of complex 3A. Furthermore, complex 3A can significantly inhibit the proliferation of A549 3D tumor spheroid. An in vivo anticancer study showed that complex 3A could delays the growth of A549 tumor xenografts with lower systemic toxicity. These results highlight the great possibility of developing highly active copper complexes as anti-lung cancer agents.

Spatiotemporal Distribution and Function of Mitochondria in Oocytes

Mitochondria are energy provider organelles in eukaryotic cells that contain their own specific genome. This review addresses structural and functional properties of mitochondria, focusing on recent discoveries about the changes in quality and number of mitochondria per cell during oocyte development. We highlight how oocyte mitochondria exhibit stage-specific morphology and characteristics at different stages of development, in sharp contrast to the elongated mitochondria present in somatic cells. We then evaluate the latest transcriptomic data to elucidate the complex functions of mitochondria during oocyte maturation and the impact of mitochondria on oocyte development. Finally, we describe the methodological progress of mitochondrial replacement therapy to rescue oocytes with developmental disorders or mitochondrial diseases, hoping to provide a guiding reference to future clinical applications.

KAT8 functions in redox homeostasis and mitochondrial dynamics during mouse oocyte meiosis progression

As a histone acetyltransferase, lysine acetyltransferase 8 (KAT8) participates in diverse biological processes. However, the effect of KAT8 on oocyte maturation in mice remains unclear. In this study, we found that mouse oocytes overexpressing Kat8-OE induced maturation failure manifested reduced rates of GVBD and first polar body emission. In addition, immunostaining results revealed that Kat8 overexpressing oocytes showed inappropriate mitochondrial distribution patterns, overproduction of reactive oxygen species (ROS), accumulation of phosphorylated γH2AX, hyperacetylation of α-tubulin, and severely disrupted spindle/chromosome organization. Moreover, we revealed that Kat8 overexpression induced a decline in SOD1 proteins and KAT8's interaction with SOD1 in mouse ovaries via immunoprecipitation. Western blotting data confirmed that Kat8-OE induced downregulation of SOD1 expression, which is a key factor for the decline of oocyte quality in advanced maternal age. Also, the injection of Myc-Sod1 cRNA could partially rescue maternal age-induced meiotic defects in oocytes. In conclusion, our data demonstrated that high level of KAT8 inhibited SOD1 activity, which in turn induced defects of mitochondrial dynamics, imbalance of redox homeostasis, and spindle/chromosome disorganization during mouse oocyte maturation.

Sirtuin 3-mediated deacetylation of superoxide dismutase 2 ameliorates sodium fluoride-induced mitochondrial dysfunction in porcine oocytes

Fluoride exerts detrimental effects on germ cells and increases the infertility rate in women. Nevertheless, the precise mechanisms behind the developmental abnormalities caused by fluoride in oocytes remain poorly comprehended. The current study, we established mitochondrial damage model in oocytes via 50 μg/mL sodium fluoride (NaF) supplementation. We then examined the effects of honokiol in preventing mitochondrial deficits caused by NaF and investigated the mechanisms through which honokiol protects oocytes. The findings investigated that NaF increased levels of mitochondrial reactive oxygen species (mtROS) and hindered mitochondrial function, as evidenced by the dissipation of mitochondrial membrane potential, abnormal expression of mitochondrial DNA copy numbers, and mtDNA harm in oocytes. mtROS scavenging using Mito-TEMPO alleviated oxidative damage in mitochondria and restored the oocyte developmental competence. Superoxide dismutase 2 (SOD2) acetylation was significantly increased, whereas sirtuin 3 (SIRT3) expression was decreased in NaF-treated oocytes. The addition of honokiol helped in the deacetylation of SOD2 at K122 through SIRT3, resulting in the removal of excessive mtROS and the recovery of mitochondrial function. Therefore, SIRT3/SOD2 pathway aids honokiol in mitigating fluoride-induced mitochondrial dysfunction. Overall, honokiol improved the mitochondrial harm caused by NaF by controlling mtROS and mitochondrial function, with the SIRT3/SOD2 pathway having an important function. These findings suggest honokiol as a potential therapeutic strategy for NaF-induced oocyte development and mitochondrial deficits.

SIRT3 Regulates Levels of Deacetylated SOD2 to Prevent Oxidative Stress and Mitochondrial Dysfunction During Oocyte Maturation in Pigs

Mammalian oocyte maturation relies on mitochondrial ATP production, but this can lead to damaging reactive oxygen species (ROS). SIRT3, a mitochondrial sirtuin, plays a critical role in regulating mitochondrial redox balance in mouse oocytes under stress; however, its specific roles in porcine oocytes remain unclear. In this study, we utilized the SIRT3 inhibitor 3-TYP to investigate SIRT3's importance in porcine oocyte maturation. Our findings revealed that SIRT3 is expressed in porcine oocytes and its inhibition leads to maturation failure. This was evident through reduced polar body extrusion, arrested cell cycle, as well as disrupted spindle organization and actin distribution. Furthermore, SIRT3 inhibition resulted in a decrease in mitochondrial DNA copy numbers, disruption of mitochondrial membrane potential, and reduced ATP levels, all indicating impaired mitochondrial function in porcine oocytes. Additionally, the primary source of damaged mitochondria was associated with decreased levels of deacetylated superoxide dismutase 2 (SOD2) after SIRT3 inhibition, which led to ROS accumulation and oxidative stress-induced apoptosis. Taken together, our results suggest that SIRT3 regulates the levels of deacetylated SOD2 to maintain redox balance and preserve mitochondrial function during porcine oocyte maturation, with potential implications for improving pig reproduction.

Wild-type S100A3 and S100A13 restore calcium homeostasis and mitigate mitochondrial dysregulation in pulmonary fibrosis patient-derived cells

Patients with digenic S100A3 and S100A13 mutations exhibited an atypical and progressive interstitial pulmonary fibrosis, with impaired intracellular calcium homeostasis and mitochondrial dysfunction. Here we provide direct evidence of a causative effect of the mutation on receptor mediated calcium signaling and calcium store responses in control cells transfected with mutant S100A3 and mutant S100A13. We demonstrate that the mutations lead to increased mitochondrial mass and hyperpolarization, both of which were reversed by transfecting patient-derived cells with the wild type S100A3 and S100A13, or extracellular treatment with the recombinant proteins. In addition, we demonstrate increased secretion of inflammatory mediators in patient-derived cells and in control cells transfected with the mutant-encoding constructs. These findings indicate that treatment of patients' cells with recombinant S100A3 and S100A13 proteins is sufficient to normalize most of cellular responses, and may therefore suggest the use of these recombinant proteins in the treatment of this devastating disease.

The impact of a maternal and offspring obesogenic diet on daughter's oocyte mitochondrial ultrastructure and bioenergetic responses. Insights from an outbred mouse model

Obesity affects oocyte mitochondrial functions and reduces oocyte quality and fertility. Obesity may also increase the risk of metabolic disorders in the offspring. Children are likely to follow their parents lifestyle and diet, which also contributes to the increased prevelance of obesity across generations. We hypothesise that the impact of obesogenic (OB) diet and obesity on oocyte mitochondrial functions is different in offspring born to obese mothers compared to those born to healthy mothers. To test this hypothesis, we fed a control (C, 10% fat, 7% sugar) or an OB diet (60% fat, 20% sugar) to female mice (for 7 weeks (w)) and then to their female offspring (for 7w after weaning) in a 2 × 2 factorial design (C » C, n = 35, C » OB, n = 35, OB » C n = 49 and OB » OB, n = 50). Unlike many other studies, we used an outbred Swiss mouse model to increase the human pathophysiological relevance. Offspring were sacrificed at 10w and their oocytes were collected. Offspring OB diet increased oocyte lipid droplet content, mitochondrial activity and reactive oxygen species (ROS) levels, altered mitochondrial ultrastructure and reduced oocyte pyruvate consumption. Mitochondrial DNA copy numbers and lactate production remained unaffected. Mitochondrial ultrastructure was the only factor where a significant interaction between maternal and offspring diet effect was detected. The maternal OB background resulted in a small but significant increase in offspring's oocyte mitochondrial ultrastructural abnormalities without altering mitochondrial inner membrane potential, active mitochondrial distribution, mitochondrial DNA copy numbers, or ROS production. This was associated with reduced mitochondrial complex III and V expression and reduced pyruvate consumption which may be compensatory mechanisms to control mitochondrial inner membrane potential and ROS levels. Therefore, in this Swiss outbred model, while offspring OB diet had the largest functional impact on oocyte mitochondrial features, the mitochondrial changes due to the maternal background appear to be adaptive and compensatory rather than dysfunctional.

pH-Responsive Upconversion Mesoporous Silica Nanospheres for Combined Multimodal Diagnostic Imaging and Targeted Photodynamic and Photothermal Cancer Therapy

Photodynamic therapy (PDT) and photothermal therapy (PTT) have gained considerable attention as potential alternatives to conventional cancer treatments. However, these approaches remain limited by low solubility, poor stability, and inefficient targeting of many common photosensitizers (PSs) and photothermal agents (PTAs). To overcome the aforementioned limitations, we engineered biocompatible and biodegradable tumor-targeted upconversion nanospheres with imaging capabilities. The multifunctional nanospheres consist of a sodium yttrium fluoride core doped with lanthanides (ytterbium, erbium, and gadolinium) and the PTA bismuth selenide (NaYF4:Yb/Er/Gd,Bi2Se3) enveloped in a mesoporous silica shell that encapsulates a PS, chlorin e6 (Ce6), within its pores. NaYF4:Yb/Er converts deeply penetrating near-infrared (NIR) light to visible light, which excites Ce6 to generate cytotoxic reactive oxygen species (ROS), while Bi2Se3 efficiently converts absorbed NIR light to heat. Additionally, Gd enables magnetic resonance imaging of the nanospheres. The mesoporous silica shell is coated with DPPC/cholesterol/DSPE-PEG to retain the encapsulated Ce6 and prevent serum protein adsorption and macrophage recognition that hinder tumor targeting. Finally, the coat is conjugated to the acidity-triggered rational membrane (ATRAM) peptide, which promotes specific and efficient internalization into malignant cells in the mildly acidic microenvironment of tumors. The nanospheres facilitated tumor magnetic resonance and thermal and fluorescence imaging and exhibited potent NIR laser light-induced anticancer effects in vitro and in vivo via combined ROS production and localized hyperthermia, with negligible toxicity to healthy tissue, hence markedly extending survival. Our results demonstrate that the ATRAM-functionalized, lipid/PEG-coated upconversion mesoporous silica nanospheres (ALUMSNs) offer multimodal diagnostic imaging and targeted combinatorial cancer therapy.

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.

Maternal exposure to cetylpyridinium chloride impairs oogenesis by causing mitochondria disorder in neonates

Cetylpyridinium Chloride (CPC) is a common disinfectant with potential mitochondrial toxicity. However, the effects of CPC on female reproduction remains unclear. In the present study, pregnant mice were exposed to environmentally relevant doses of CPC for 3 days, the effects were evaluated in the female offspring. Maternal exposure to CPC caused loss of oocytes in neonatal ovaries. TEM analysis of neonatal ovaries showed CPC caused aberrant mitochondrial morphology including vacuolated and disorganized structure, reduced functional cristae. In addition, CPC decreased mitochondrial membrane potential in neonatal oocytes. Seahorse analysis showed that CPC hampered mitochondrial reserve, manifested as reduced spare respiratory capacity. Furthermore, CPC damaged mitochondrial function and impaired developmental competence of MII oocytes, suggesting a persisting impact into adulthood. In summary, this is the first known demonstration that maternal exposure to CPC caused mitochondrial disorders in neonatal ovaries and had long-term effects on fertility of the female offspring.

Coenzyme Q10 Stimulate Reproductive Vatality

Female infertility and pregnancy maintenance are associate with various factors, including quantity and quality of oocytes, genital inflammation, endometriosis, and other diseases. Women are even diagnosed as unexplained infertility or unexplained recurrent spontaneous abortion when failed to achieve pregnancy with current treatment, which are urgent clinical issues need to be addressed. Coenzyme Q10 (CoQ10) is a lipid-soluble electron carrier in the mitochondrial electron transport chain. It is not only essential for the mitochondria to produce energy, but also function as an antioxidant to maintain redox homeostasis in the body. Recently, the capacity of CoQ10 to reduce oxidative stress (OS), enhance mitochondrial activity, regulate gene expression and inhibit inflammatory responses, has been discovered as a novel adjuvant in male reproductive performance enhancing in both animal and human studies. Furthermore, CoQ10 is also proved to regulate immune balance, antioxidant, promote glucose and lipid metabolism. These properties will bring highlight for ovarian dysfunction reversing, ovulation ameliorating, oocyte maturation/fertilization promoting, and embryonic development optimizing. In this review, we systematically discuss the pleiotropic effects of CoQ10 in female reproductive disorders to investigate the mechanism and therapeutic potential to provide a reference in subsequent studies.

Nivalenol disrupts mitochondria functions during porcine oocyte meiotic maturation

Oocyte maturation is important for fertility in mammals, since the quality of oocytes directly affects fertilization, embryo attachment and survival. Nivalenol is widely present in nature as a common toxin that contaminates grain and feed, and it has been reported to cause acute toxicity, immunotoxicity, reproductive toxicity and carcinogenic effects. In this study, we explored the impact of nivalenol on the porcine oocyte maturation and its possible mechanisms. The extrusion of the first polar body was significantly inhibited after incubating oocytes with nivalenol. Meanwhile, nivalenol exposure led to the abnormal distribution of mitochondria, aberrant calcium concentration and the reduction of membrane potential caused a significant decrease in the capacity of mitochondria to generate ATP. In addition, nivalenol induced oxidative stress, and the level of ROS was significantly increased in the nivalenol-treated group, which was confirmed by the perturbation of oxidative stress-related genes. We found that nivalenol-treated oocytes showed positive Annexin-V and γH2A.X signals, indicating the occurrence of apoptosis and DNA damage. In all, our data suggest that nivalenol disrupted porcine oocyte maturation through its effects on mitochondria-related oxidative stress, apoptosis and DNA damage.

BPA interferes with granulosa cell development and oocyte meiosis in mouse preantral follicles

Bisphenol A (BPA) is an established environmental endocrine disruptor and can interfere with the development of female germ cells. However, the underlying mechanisms are still unclear. We investigated the effects of BPA on granulosa cell development and meiosis of oocytes using in vitro culture system of mouse preantral follicles. Preantral follicles from D14 mouse ovary were treated with 10 μg/mL BPA in vitro for 11 days. The adherent area of follicles was measured. On D11, cumulus cell expansion was observed. The meiosis recovery rate was calculated. Western blot detected P53, proliferating cell nuclear antigen (PCNA), estrogen receptor α (ERα), and cyclin B1. ELISA measured estrogen and progesterone levels. Immunofluorescence detected Cx37 on oocyte membrane. Gap junction communication was assessed. We found that BPA significantly promoted the expressions of PCNA and ERα in granulosa cells and the secretion of estrogen and progesterone by granulosa cells on D10 and significantly increased the attachment area of the follicles on D8 and D10. However, it reduced the expansion of cumulus cells, Cx37 expression, and the gap junction communication between cumulus cells and oocytes on D11. BPA promoted the recovery of oocytes from meiosis, interrupted the expression of cyclin B1 protein in arrested germinal vesicle breakdown (GVBD) oocytes, and reduced the in vitro maturation rate of oocytes. These GVBD oocytes were live without apoptosis or death. Conclusively, BPA disturbs the development of granulosa cells and the meiosis progression of oocytes by decreasing gap junction communication between oocytes and the granulosa cells as well as regulating cyclin B1 expression in GVBD oocytes.

Oxygen consumption rate to evaluate mitochondrial dysfunction and toxicity in cardiomyocytes

The increase in the types and complexity of diseases has led to significant advances in diagnostic techniques and the availability of effective therapies. Recent studies have focused on the role of mitochondrial dysfunction in the pathogenesis of cardiovascular diseases (CVDs). Mitochondria are important organelles in cells that generate energy. Besides the production of adenosine triphosphate (ATP), the energy currency of cells, mitochondria are also involved in thermogenesis, control of intracellular calcium ions (Ca2+), apoptosis, regulation of reactive oxygen species (ROS), and inflammation. Mitochondrial dysfunction has been implicated in several diseases including cancer, diabetes, some genetic diseases, and neurogenerative and metabolic diseases. Furthermore, the cardiomyocytes of the heart are rich in mitochondria due to the large energy requirement for optimal cardiac function. One of the main causes of cardiac tissue injuries is believed to be mitochondrial dysfunction, which occurs via complicated pathways which have not yet been completely elucidated. There are various types of mitochondrial dysfunction including mitochondrial morphological change, unbalanced levels of substances to maintain mitochondria, mitochondrial damage by drugs, and mitochondrial deletion and synthesis errors. Most of mitochondrial dysfunctions are linked with symptoms and diseases, thus we focus on parts of mitochondrial dysfunction about fission and fusion in cardiomyocytes, and ways to understand the mechanism of cardiomyocyte damage by detecting oxygen consumption levels in the mitochondria.

Role of insulin-like growth factor 1 (IGF1) in the regulation of mitochondrial bioenergetics in zebrafish oocytes: lessons from in vivo and in vitro investigations

Optimal mitochondrial functioning is indispensable for acquiring oocyte competence and meiotic maturation, whilst mitochondrial dysfunction may lead to diminished reproductive potential and impaired fertility. The role of the intra-ovarian IGF system in ovarian follicular dynamics has been implicated earlier. Although several studies have demonstrated the role of the IGF axis in facilitating mitochondrial function over a multitude of cell lines, its role in oocyte energy metabolism remains largely unexplored. Here using zebrafish, the relative importance of IGF1 in modulating oocyte mitochondrial bioenergetics has been investigated. A dramatic increase in ovarian lhcgr and igf1 expression accompanied heightened ATP levels and mitochondrial polarization in full-grown (FG) oocytes resuming meiotic maturation and ovulation in vivo. Concomitant with elevated igf1 expression and IGF1R phosphorylation, hCG (LH analog) stimulation of FG follicles in vitro prompted a sharp increase in NRF-1 and ATP levels, suggesting a positive influence of gonadotropin action on igf1 expression vis-à-vis oocyte bioenergetics. While recombinant IGF1 administration enhanced mitochondrial function, IGF1R immunodepletion or priming with PI3K inhibitor wortmannin could abrogate NRF-1 immunoreactivity, expression of respiratory chain subunits, ΔΨ_M, and ATP content. Mechanistically, activation of PI3K/Akt signaling in IGF1-treated follicles corroborated well with the rapid phosphorylation of GSK3β at Ser9 (inactive) followed by PGC-1β accumulation. While selective inhibition of GSK3β promoted PGC-1β, Akt inhibition could abrogate IGF1-induced p-GSK3β (Ser9) and PGC-1β immunoreactive protein indicating Akt-mediated GSK3β inactivation and PGC-1β stabilization. The IGF1-depleted follicles showed elevated superoxide anions, subdued steroidogenic potential, and attenuated G2-M1 transition. In summary, this study highlights the importance of IGF1 signaling in oocyte bioenergetics prior to resumption of meiosis.

Effects of meiotic stage-specific oocyte vitrification on mouse oocyte quality and developmental competence

Introduction

Acquisition of germinal vesicle (GV) stage oocytes for fertility preservation (FP) offers several benefits over in vivo matured oocyte cryopreservation following ovarian stimulation, particularly for cancer patients necessitating immediate treatment. Two FP approaches for GV oocytes are available: vitrification before in vitro maturation (IVM) at the GV stage (GV-VI) or post-IVM at the metaphase II (MII) stage (MII-VI). The optimal method remains to be determined.

Methods

In this study, mouse oocytes were collected without hormonal stimulation and vitrified either at the GV stage or the MII stage following IVM; non-vitrified in vitro matured MII oocytes served as the control (CON). The oocyte quality and developmental competence were assessed to obtain a better method for immediate FP.

Results

No significant differences in IVM and survival rates were observed among the three groups. Nevertheless, GV-VI oocytes exhibited inferior quality, including abnormal spindle arrangement, mitochondrial dysfunction, and early apoptosis, compared to MII-VI and CON oocytes. Oocyte vitrification at the GV stage impacted maternal mRNA degradation during IVM. In addition, the GV-VI group demonstrated significantly lower embryonic developmental competence relative to the MII-VI group. RNA sequencing of 2-cell stage embryos revealed abnormal minor zygotic genome activation in the GV-VI group.

Conclusion

Vitrification at the GV stage compromised oocyte quality and reduced developmental competence. Consequently, compared to the GV stage, oocyte vitrification at the MII stage after IVM is more suitable for patients who require immediate FP.

pH-responsive upconversion mesoporous silica nanospheres for combined multimodal diagnostic imaging and targeted photodynamic and photothermal cancer therapy

Photodynamic therapy (PDT) and photothermal therapy (PTT) have garnered considerable interest as non-invasive cancer treatment modalities. However, these approaches remain limited by low solubility, poor stability and inefficient targeting of many common photosensitizers (PSs) and photothermal agents (PTAs). To overcome these limitations, we have designed biocompatible and biodegradable tumor-targeted upconversion nanospheres with imaging capabilities. The multifunctional nanospheres consist of a sodium yttrium fluoride core doped with lanthanides (ytterbium, erbium and gadolinium) and bismuth selenide (NaYF 4 :Yb/Er/Gd,Bi 2 Se 3 ) within a mesoporous silica shell that encapsulates a PS, Chlorin e6 (Ce6), in its pores. NaYF 4 :Yb/Er converts deeply penetrating near-infrared (NIR) light to visible light, which excites the Ce6 to generate cytotoxic reactive oxygen species (ROS), while the PTA Bi 2 Se 3 efficiently converts absorbed NIR light to heat. Additionally, Gd enables magnetic resonance imaging (MRI) of the nanospheres. The mesoporous silica shell is coated with lipid/polyethylene glycol (DPPC/cholesterol/DSPE-PEG) to ensure retention of the encapsulated Ce6 and minimize interactions with serum proteins and macrophages that impede tumor targeting. Finally, the coat is functionalized with the acidity-triggered rational membrane (ATRAM) peptide, which promotes specific and efficient internalization into cancer cells within the mildly acidic tumor microenvironment. Following uptake by cancer cells in vitro , NIR laser irradiation of the nanospheres caused substantial cytotoxicity due to ROS production and hyperthermia. The nanospheres facilitated tumor MRI and thermal imaging, and exhibited potent NIR laser light-induced antitumor effects in vivo via combined PDT and PTT, with no observable toxicity to healthy tissue, thereby substantially prolonging survival. Our results demonstrate that the ATRAM-functionalized, lipid/PEG-coated upconversion mesoporous silica nanospheres (ALUMSNs) offer multimodal diagnostic imaging and targeted combinatorial cancer therapy.

In Vitro Evaluation Reveals Effect and Mechanism of Artemether against Toxoplasma gondii

Due to the limited effectiveness of existing drugs for the treatment of toxoplasmosis, there is a dire need for the discovery of new therapeutic options. Artemether is an important drug for malaria and several studies have indicated that it also exhibits anti-T. gondii activity. However, its specific effect and mechanisms are still not clear. To elucidate its specific role and potential mechanism, we first evaluated its cytotoxicity and anti-Toxoplasma effect on human foreskin fibroblast cells, and then analyzed its inhibitory activity during T. gondii invasion and intracellular proliferation. Finally, we examined its effect on mitochondrial membrane potential and reactive oxygen species (ROS) in T. gondii. The CC50 value of artemether was found to be 866.4 μM, and IC50 was 9.035 μM. It exhibited anti-T. gondii activity and inhibited the growth of T. gondii in a dose-dependent manner. We also found that the inhibition occurred primarily in intracellular proliferation, achieved by reducing the mitochondrial membrane integrity of T. gondii and stimulating ROS production. These findings suggest that the mechanism of artemether against T. gondii is related to a change in the mitochondrial membrane and the increase in ROS production, which may provide a theoretical basis for optimizing artemether derivatives and further improving their anti-Toxoplasma efficacy.

Intermittent fasting reverses the declining quality of aged oocytes

Decreased oocyte quality and compromised embryo development are particularly prevalent in older females, but the aging-related cellular processes and effective ameliorative approaches have not been fully characterized. Intermittent fasting (IF) can help improve health and extend lifespan; nevertheless, how it regulates reproductive aging and its mechanisms remain unclear. We used naturally aged mice to investigate the role of IF in reproduction and found that just one month of every-other-day fasting was sufficient to improve oocyte quality. IF not only increased antral follicle numbers and ovulation but also enhanced oocyte meiotic competence and embryonic development by improving both nuclear and cytoplasmic maturation in maternally aged oocytes. The beneficial effects of IF manifested as alleviation of spindle structure abnormalities and chromosome segregation errors and maintenance of the correct cytoplasmic organelle reorganization. Moreover, single-cell transcriptome analysis showed that the positive impact of IF on aged oocytes was mediated by restoration of the nicotinamide adenine dinucleotide (NAD+)/Sirt1-mediated antioxidant defense system, which eliminated excessive accumulated ROS to suppress DNA damage and apoptosis. Collectively, these findings suggest that IF is a feasible approach to protect oocytes against advanced maternal age-related oxidation damage and to improve the reproductive outcomes of aged females.

Adverse PFAS effects on mouse oocyte in vitro maturation are associated with carbon-chain length and inclusion of a sulfonate group

OBJECTIVES

Per- and polyfluoroalkyl substances (PFAS) are man-made chemicals that are widely used in various products. PFAS are characterized by their fluorinated carbon chains that make them hard to degrade and bioaccumulate in human and animals. Toxicological studies have shown PFAS toxic effects: cytotoxicity, immunotoxicity, neurotoxicity, and reproductive toxicity. However, it is still unclear how the structures of PFAS, such as carbon-chain length and functional groups, determine their reproductive toxicity.

METHODS AND RESULTS

By using a mouse-oocyte-in-vitro-maturation (IVM) system, we found the toxicity of two major categories of PFAS, perfluoroalkyl carboxylic acid (PFCA) and perfluoroalkyl sulfonic acid (PFSA), is elevated with increasing carbon-chain length and the inclusion of the sulfonate group. Specifically, at 600 μM, perfluorohexanesulfonic acid (PFHxS) and perfluorooctanesulfonic acid (PFOS) reduced the rates of both germinal-vesicle breakdown (GVBD) and polar-body extrusion (PBE) as well as enlarged polar bodies. However, the shorter PFSA, perfluorobutanesulfonic acid (PFBS), and all PFCA did not show similar adverse cytotoxicity. Further, we found that 600 μM PFHxS and PFOS exposure induced excess reactive oxygen species (ROS) and decreased mitochondrial membrane potential (MMP). Cytoskeleton analysis revealed that PFHxS and PFOS exposure induced chromosome misalignment, abnormal F-actin organization, elongated spindle formation, and symmetric division in the treated oocytes. These meiotic defects compromised oocyte developmental competence after parthenogenetic activation.

CONCLUSIONS

Our study provides new information on the structure-toxicity relationship of PFAS.

Effect of bovine oocyte vitrification with EGTA and post-warming recovery with resveratrol on meiotic spindle, mitochondrial function, reactive oxygen species, and developmental competence

The present study aimed to determine the effects of the addition of EGTA to vitrification solutions and a post-warming recovery period supplemented with 1 μM resveratrol on meiotic spindle integrity, mitochondrial activity, ATP content, reactive oxygen species (ROS) levels, and developmental potential of partially denuded, vitrified-warmed bovine oocytes. Results of microtubule distribution and chromosomal arrangement indicated that resveratrol supplementation, irrespective to EGTA addition, reduced the incidence of abnormal meiotic spindles to similar levels of the control group. Mitochondrial membrane potential was similar in all groups, but ATP content was negatively affected by the vitrification-warming procedure and failed to recover after 4 h of post-warming culture. Resveratrol caused the reduction of ROS to lower levels of the control group, and showed the lowest ROS levels when combined with EGTA treatment. Oocytes in all vitrification groups presented lower developmental potential when compared to fresh oocytes. However, oocytes that underwent vitrification supplemented with EGTA and post-warming culture along with resveratrol showed higher developmental competence compared with vitrified-warmed oocytes not supplemented with resveratrol. The results of our study indicate that submitting vitrified-warmed, partially denuded bovine oocytes to a post-warming recovery period supplemented with 1 μM resveratrol improves vitrification outcomes. However, the benefits of EGTA on vitrification and warming of bovine oocytes need to be further investigated.

Investigation of He's Yang Chao recipe against oxidative stress-related mitophagy and pyroptosis to improve ovarian function

BACKGROUND

Primary ovarian insufficiency (POI) is a common gynecological disease with serious ramifications including low pregnancy rate and low estrogen symptoms. Traditional Chinese medicine is regarded as an effective treatment for POI. However, the therapeutic mechanism of it is unclear.

METHODS

In this study, a mouse model of primary ovarian insufficiency was established by intraperitoneal injection of cyclophosphamide (CTX) and He's Yang Chao Recipe (HSYC) concentrate was used for intragastric administration. Serum hormone levels (Anti-Müllerian Hormone, Estradiol, Progesterone, Luteinizing Hormone and Follicle Stimulating Hormone) and Oxidative Stress (OS) related products, superoxide dismutase (SOD), GSH-Px, and malondialdehyde (MDA) were measured by enzyme-linked immunosorbent assay. Pathological changes in ovarian tissue were evaluated by hematoxylin and eosin staining, and flow cytometry was used to determine reactive oxygen species content and mitochondrial membrane potential levels in granulosa cells. Mitochondrial distribution and morphology were investigated using immunofluorescence staining. The level of mitophagy was evaluated by LC3 immunofluorescence staining and autophagosome counts using electron microscopy. Western blotting and qPCR were used to detect the expression of proteins and genes related to mitophagy and the NLRP3 inflammasome.

RESULTS

After HSYC treatment, the ovarian damage was milder than in the CTX group. Compared with the CTX group; SOD, GSH-Px, and the total antioxidant capacity were significantly increased, while MDA and ROS were decreased in the HSYC treatment groups. Furthermore, mitochondrial distribution and membrane potential levels were improved after HSYC treatment compared to the CTX group. After the HSYC treatment, the LC3 fluorescent intensity and autophagosome counts were decreased. Similarly, mitophagy related markers PINK1, Parkin, LC3, and Beclin1 were decreased, while p62 was significantly increased, compared with the CTX groups. The mRNA and protein expression of NLRP3 inflammasome, NLRP3, caspase-1, GSDMD, IL-18, and IL-1β were significantly decreased in the HSYC treatment groups.

CONCLUSION

This is the first study in molecular mechanisms underlying HSYC against granulosa cell injury in POI. HSYC protects ovaries from CTX-induced ovarian damage and oxidative stress. HSYC enhanced ovarian function in mice with primary ovarian insufficiency by inhibiting PINK1-Parkin mitophagy and NLRP3 inflammasome activation.

3-MCPD exposure enhances ovarian fibrosis and reduces oocyte quality in mice

3-monochloro-1,2-propanediol (3-MCPD) is a food contaminant believed to be harmful to human health. Previous studies showed that 3-MCPD exerts toxic effects in multiple tissues, but whether 3-MCPD affects female reproductive function remained unknown. Here, using mouse gastric lavage models, we report that 3-MCPD exposure for four weeks affected body growth, decreased the ovary/body weight ratio, and increased atretic follicle numbers. Expression levels of follicular development-related factors decreased. Further studies found that ovaries from 3-MCPD exposed mice had activated the Transforming Growth Factor-β (TGF-β) signaling pathway and promoted ovarian fibrosis. Increased TNF-α, IL-1 and NF-κB expression also indicated the occurrence of ovarian inflammation. Exposure to 3-MCPD stimulated the caspase pathway and enhanced granulosa cell apoptosis. Consistent with disrupted ovarian homeostasis, 3-MCPD exposure interfered with mitochondrial function, generated more reactive oxygen species, increased ferrous ion and lipid peroxidation levels, and resulted in decreased oocyte development potential. Collectively, these findings indicated that 3-MCPD exposure induced ovarian inflammation and fibrosis, and caused disorders of mitochondrial function and ferrous ion homeostasis in oocytes, which consequently disturbed follicle maturation and reduced oocyte quality.

The significance of bioelectricity on all levels of organization of an organism. Part 1: From the subcellular level to cells

Bioelectricity plays an essential role in the structural and functional organization of biological organisms. In this first article of our three-part series, we summarize the importance of bioelectricity for the basic structural level of biological organization, i.e. from the subcellular level (charges, ion channels, molecules and cell organelles) to cells.

Oocyte aging in comparison to stem cells in mice

To maintain homeostasis, many tissues contain stem cells that can self-renew and differentiate. Based on these functions, stem cells can reconstitute the tissue even after injury. In reproductive organs, testes have spermatogonial stem cells that generate sperm in men throughout their lifetime. However, in the ovary, oocytes enter meiosis at the embryonic stage and maintain sustainable oogenesis in the absence of stem cells. After birth, oocytes are maintained in a dormant state in the primordial follicle, which is the most premature follicle in the ovary, and some are activated to form mature oocytes. Thus, regulation of dormancy and activation of primordial follicles is critical for a sustainable ovulatory cycle and is directly related to the female reproductive cycle. However, oocyte storage is insufficient to maintain a lifelong ovulation cycle. Therefore, the ovary is one of the earliest organs to be involved in aging. Although stem cells are capable of proliferation, they typically exhibit slow cycling or dormancy. Therefore, there are some supposed similarities with oocytes in primordial follicles, not only in their steady state but also during aging. This review aims to summarise the sustainability of oogenesis and aging phenotypes compared to tissue stem cells. Finally, it focuses on the recent breakthroughs in vitro culture and discusses future prospects.

Quercetin protects mouse oocytes against chromium-induced damage in vitro and in vivo

BACKGROUND

Chromium (Cr) is a naturally-occurring element that is used in various fields of industry. Humans may be exposed to hexavalent chromium [Cr(VI)], which is one of the stable valence states of the chromium through contaminated soil, air, and water. Exposure to Cr(VI) through contaminated drinking water, soil and air causes various cancers and also fertility problems in animals and humans. Quercetin (QCT), a common flavonoid compound, has numerous biological effects as an antioxidant and free radical scavenger, but its function and mechanisms in reproductive processes in various species remain unclear. This study aims to determine the chromium effects on mice oocyte quality and the ameliorative effect of QCT in both in vitro and in vivo experimental models.

METHODS

For the in vitro experiment, oocytes were collected and divided into the control, sham, QCT-treated, Cr(VI) (potassium dichromate), and treatment [Cr(VI)+QCT] groups. Collected oocytes were cultured in maturation medium with or without 10 µM quercetin and 10 µM Cr(VI) for 14 h based on the defined experimental design. For the in vivo experiment, the mice were randomly divided into the control, sham, QCT-treated, Cr(VI), and Cr(VI) + QCT groups. Control and sham mice received regular drinking water and diet. Cr(VI) group received Cr(VI) (50 ppm in drinking water) and Cr(VI) + QCT group received 50 ppm Cr(VI) with QCT (20 mg/kg body wt, through i.p) for a period of 21 days and then oocytes were collected and cultured for 14 h for in vitro maturation. For both experiments, at the end of the culture period, we examined the ameliorative effect of QCT on oocyte maturation, spindle formation, ROS production, mitochondrial function, and apoptosis.

RESULTS

Our in vitro and in vivo results showed that Cr(VI) disrupt the oocyte maturation and spindle formation (P < 0.001). Furthermore, we found that exposure to Cr(VI) significantly increased ROS levels and decreased mitochondrial membrane potential (P < 0.001). In addition, exposure to Cr(VI) induced early apoptosis and downregulated the Bcl-2 mRNA expression and upregulated the Caspase-3 and Bax mRNAs expression (P < 0.01). Finally, quercetin significantly restored the detrimental effects of Cr(VI).

CONCLUSION

The results indicated that quercetin protects the oocytes against Cr(VI) toxicity through the suppression of oxidative stress and apoptosis. The conclusions drawn from our study's findings suggest that quercetin might be useful agent for oocyte maturation in case of possible exposure to toxic substances such as chromium.

Mammalian oocytes store mRNAs in a mitochondria-associated membraneless compartment

Full-grown oocytes are transcriptionally silent and must stably maintain the messenger RNAs (mRNAs) needed for oocyte meiotic maturation and early embryonic development. However, where and how mammalian oocytes store maternal mRNAs is unclear. Here, we report that mammalian oocytes accumulate mRNAs in a mitochondria-associated ribonucleoprotein domain (MARDO). MARDO assembly around mitochondria was promoted by the RNA-binding protein ZAR1 and directed by an increase in mitochondrial membrane potential during oocyte growth. MARDO foci coalesced into hydrogel-like matrices that clustered mitochondria. Maternal mRNAs stored in the MARDO were translationally repressed. Loss of ZAR1 disrupted the MARDO, dispersed mitochondria, and caused a premature loss of MARDO-localized mRNAs. Thus, a mitochondria-associated membraneless compartment controls mitochondrial distribution and regulates maternal mRNA storage, translation, and decay to ensure fertility in mammals.

Miro1 depletion disrupts spatial distribution of mitochondria and leads to oocyte maturation defects

Mitochondria are dynamic organelles that undergo regulated microtubule- and actin-mediated trafficking to meet local energy and metabolic needs. Mitochondrial trafficking may be particularly critical in large cells such as eggs and early embryos where spindle formation and polar body extrusion occur in specific regions of the cytoplasm. To investigate the role of mitochondrial distribution in oocytes we have targeted the mitochondrial membrane protein, MIRO1, which couples mitochondria to the motor protein-TRAK complex. Oocyte-specific deletion of MIRO1 leads to the formation of large aggregates of mitochondria in perinuclear and cortical compartments. Mitochondria remain capable of long-range trafficking during maturation, indicating redundancy in the mechanisms coupling mitochondria to motor proteins. Polar body extrusion in the absence of MIRO1 was reduced by approximately 20%. In MIRO1-deleted zygotes, mitochondria showed increased accumulation around the pronuclei but this did not affect mitochondrial distribution to daughter blastomeres. In vitro development of parthenogenetic embryos was also reduced, although no differences were found in the fertility of oocyte-specific Miro1 KO mice. These findings demonstrate MIRO1 acts as a mitochondrial adaptor, setting mitochondrial distribution in oocytes and early embryos, and disrupting this process compromises in vitro oocyte maturation and embryo development.

Glyphosate decreases bovine oocyte quality by inducing oxidative stress and apoptosis

Glyphosate is a universal herbicide with genital toxicity, but the effect of glyphosate on oocytes has not been reported. This study aimed to evaluate the effect of glyphosate (0, 10, 20, 50 and 100 mM) on bovine oocyte in vitro maturation. We showed that 50 mM glyphosate adversely affects the development of bovine oocytes. Exposure of oocytes to 50 mM glyphosate caused an abnormal reduction in oxidative (redox) levels compared with that in the control group, with a significantly higher reactive oxide species level (P < 0.05) and significantly lower glutathione (GSH) expression (P < 0.05). Additionally, the mRNA levels of antioxidant genes (SOD1, SOD2, SIRT2, SIRT3) and the mitochondrial membrane potential (MMP) were significantly reduced (P < 0.05). Furthermore, treatment with 50 mM glyphosate-induced apoptosis, and the mRNA levels of the apoptotic genes Caspase-3 and Caspase-4 were significantly higher than those in the control group (P < 0.05); however, the mRNA level of BAX was significantly higher than that in the control group (P < 0.01). Additionally, the mRNA levels of the anti-apoptotic genes Survivin and BCL-XL were significantly lower than those in the control group (P < 0.05), and oocyte quality was adversely affected. Together, our results confirmed that glyphosate impairs the quality of oocytes by promoting abnormal oocyte redox levels and apoptosis.

Depletion of oocyte dynamin-related protein 1 shows maternal-effect abnormalities in embryonic development

Eggs contain about 200,000 mitochondria that generate adenosine triphosphate and metabolites essential for oocyte development. Mitochondria also integrate metabolism and transcription via metabolites that regulate epigenetic modifiers, but there is no direct evidence linking oocyte mitochondrial function to the maternal epigenome and subsequent embryo development. Here, we have disrupted oocyte mitochondrial function via deletion of the mitochondrial fission factor Drp1. Fission-deficient oocytes exhibit a high frequency of failure in peri- and postimplantation development. This is associated with altered mitochondrial function, changes in the oocyte transcriptome and proteome, altered subcortical maternal complex, and a decrease in oocyte DNA methylation and H3K27me3. Transplanting pronuclei of fertilized Drp1 knockout oocytes to normal ooplasm fails to rescue embryonic lethality. We conclude that mitochondrial function plays a role in establishing the maternal epigenome, with serious consequences for embryo development.

A Novel Fluorescent Dye Extracted from Buddleja officinalis for Labeling Mitochondria after Fixation

Mitochondria are versatile organelles and function by communicating with cellular ecosystems. The fluorescent colocalization analysis after fixation is a highly intuitive method to understand the role of mitochondria. However, there are few fluorescent dyes available for mitochondrial staining after fixation. In this study, a novel fluorescent dye (BO-dye), extracted from Buddleja officinalis, was applied for mitochondrial staining in fixed immortalized human oral keratinocytes. The BO-dye (excitation: 414 nm, emission: 677 nm) is a small fluorescent molecular dye, which can cross the cytomembrane without permeabilization. We assume that the BO-dye could aggregate and bind to the mitochondria stably. BO-dye exhibited a mega-Stokes shift (>250 nm), which is an important feature that could reduce self-quenching and enhance the signal-to-noise ratio. Analysis of photophysical properties revealed that the BO-dye is temperature and pH insensitive, and it exhibits superior photostability. These results indicate that BO-dye can be considered an alternative fluorescent dye for labeling mitochondria after fixation.

Oxidative stress induces meiotic defects of oocytes in a mouse psoriasis model

Psoriasis, an immune-mediated inflammatory disease, is associated with poor pregnancy outcomes. Emerging evidence indicates that these defects are likely attributed to compromised oocyte competence. Nevertheless, little is known about the underlying associated mechanisms between psoriasis and poor oocyte quality. In this study, we construct an imiquimod-induced chronic psoriasis-like mouse model to review the effects of psoriasis on oocyte quality. We discover that oocytes from psoriasis-like mice display spindle/chromosome disorganization, kinetochore-microtubule mis-attachment, and aneuploidy. Importantly, our results show that melatonin supplement in vitro and in vivo not only increases the rate of matured oocytes but also significantly attenuates oxidative stress and meiotic defects by restoring mitochondrial function in oocytes from psoriasis-like mice. Altogether, our data uncover the adverse effects of psoriasis symptoms on oocytes, and melatonin supplement ameliorates oxidative stress and meiotic defects of oocytes from psoriatic mice.