Aging hallmarks of the primate ovary revealed by spatiotemporal transcriptomics

Reduced DNMT1 expression associated with TP53 promoter hypomethylation mediate enhanced granulosa cell senescence during ovarian aging

BACKGROUND

The effects of granulose cell (GC) senescence on premature ovarian insufficiency/premature ovarian failure have been extensively examined, the association between GC senescence and ovarian aging remains to be clarified.

METHODS

Human and mouse GCs from young/control and old/advanced maternal age (AMA) groups were collected, and GC senescence was determined. The role of the DNMT1-p53 axis in GC senescence during ovarian aging was examined and validated in a KGN cell senescence model.

RESULTS

SA-beta-gal-positive GCs were significantly increased in the AMA group, accompanied by activation of the p53-p21 pathway, which was also found in GCs from aged mice and H2O2-induced senescent KGN cells. Pyrosequencing methylation analysis revealed that increased expression of p53 was associated with decreased average methylation levels of CpG sites (-1031, -1019, -1012 and -1008) within the P53 promoter CpG island in senescenct GCs and KGN cells. We further found that decreased DNA-methyltransferase 1 (DNMT1) expression was responsible for the reduced methylation levels of the CpG sites.

CONCLUSION

Decreased DNMT1 with hypomethylation of the CpG sites within the P53 promoter CpG island in GCs is involved in ovarian aging.

CKAP5 deficiency induces premature ovarian insufficiency

BACKGROUND

Premature ovarian insufficiency (POI) is characterized by ovarian dysfunction that develops from diminished ovarian reserve (DOR). The exact aetiology of POI remains poorly understood. This study aims to elucidate the role of CKAP5 in the regulation of ovarian function and fertility.

METHODS

Bulk RNA sequencing of granulosa cells was conducted in the control group and in the patients with DOR to screen for candidate genes, which were further validated by gene burden analysis in a next-generation sequencing cohort of POI and control individuals. Additionally, ovarian reserve was evaluated in heterozygous Ckap5 knockout mice, alongside the ovarian and oocyte single-cell transcriptome analysis. The regulatory mechanism of CKAP5 was studied through in vivo and in vitro experiments.

FINDINGS

CKAP5 was identified as a key hub gene associated with ovarian ageing. Heterozygous Ckap5 knockout mice exhibited a POI-like phenotype, characterized by a reduced primordial follicle pool and accelerated follicular atresia. CKAP5 promotes autophagy via ATG7 and simultaneously supports DNA damage repair through the ATM. Finally, a variant in CKAP5 (NM_0001008938.4, c.630 + 7_630 + 11delCAAAA) was identified in patients with POI, resulting in protein truncation and loss of function.

INTERPRETATION

CKAP5 deficiency induces premature ovarian insufficiency in both humans and mice.

FUNDING

The National Key R&D Program of China (2017YFC1001100), the National Natural Science Foundation of China (81501248, 81471453 and 81801295), the Health Research Project of Hunan Provincial Health Commission (W20243018), the Science and Technology Innovation Program of Hunan Province (2021RC3031), the National Natural Science Foundation of Hunan Province (2022JJ30066), the Scientific Research Program of Hunan Provincial Health Commission (202205033471 and 21B0058), the Open Research Fund of Hunan Provincial Key Laboratory of Regional Hereditary Birth Defects Prevention and Control (HPKL2023013).

Hallmarks of ovarian aging

Ovarian aging is considered to be the pacemaker of female aging, and is linked to various comorbidities such as osteoporosis, cardiovascular diseases, and cognitive decline. Many efforts have been made to determine the mechanisms underlying ovarian aging, but their potential to act as hallmarks to predict and intervene in this process currently remains unclear. In this review we propose nine hallmarks as common features of ovarian aging: genomic instability, telomere attrition, epigenetic alterations, impaired autophagy, cellular senescence, deregulated nutrient-sensing, mitochondrial dysfunction, oxidative stress, and chronic inflammation. Understanding the interaction between these hallmarks poses a significant challenge but may also pave the way to the identification of pharmaceutical targets that can attenuate ovarian aging.

Harnessing omics data for drug discovery and development in ovarian aging

BACKGROUND

Ovarian aging occurs earlier than the aging of many other organs and has a lasting impact on women's overall health and well-being. However, effective interventions to slow ovarian aging remain limited, primarily due to an incomplete understanding of the underlying molecular mechanisms and drug targets. Recent advances in omics data resources, combined with innovative computational tools, are offering deeper insight into the molecular complexities of ovarian aging, paving the way for new opportunities in drug discovery and development.

OBJECTIVE AND RATIONALE

This review aims to synthesize the expanding multi-omics data, spanning genome, transcriptome, proteome, metabolome, and microbiome, related to ovarian aging, from both tissue-level and single-cell perspectives. We will specially explore how the analysis of these emerging omics datasets can be leveraged to identify novel drug targets and guide therapeutic strategies for slowing and reversing ovarian aging.

SEARCH METHODS

We conducted a comprehensive literature search in the PubMed database using a range of relevant keywords: ovarian aging, age at natural menopause, premature ovarian insufficiency (POI), diminished ovarian reserve (DOR), genomics, transcriptomics, epigenomics, DNA methylation, RNA modification, histone modification, proteomics, metabolomics, lipidomics, microbiome, single-cell, genome-wide association studies (GWAS), whole-exome sequencing, phenome-wide association studies (PheWAS), Mendelian randomization (MR), epigenetic target, drug target, machine learning, artificial intelligence (AI), deep learning, and multi-omics. The search was restricted to English-language articles published up to September 2024.

OUTCOMES

Multi-omics studies have uncovered key mechanisms driving ovarian aging, including DNA damage and repair deficiencies, inflammatory and immune responses, mitochondrial dysfunction, and cell death. By integrating multi-omics data, researchers can identify critical regulatory factors and mechanisms across various biological levels, leading to the discovery of potential drug targets. Notable examples include genetic targets such as BRCA2 and TERT, epigenetic targets like Tet and FTO, metabolic targets such as sirtuins and CD38+, protein targets like BIN2 and PDGF-BB, and transcription factors such as FOXP1.

WIDER IMPLICATIONS

The advent of cutting-edge omics technologies, especially single-cell technologies and spatial transcriptomics, has provided valuable insights for guiding treatment decisions and has become a powerful tool in drug discovery aimed at mitigating or reversing ovarian aging. As technology advances, the integration of single-cell multi-omics data with AI models holds the potential to more accurately predict candidate drug targets. This convergence offers promising new avenues for personalized medicine and precision therapies, paving the way for tailored interventions in ovarian aging.

REGISTRATION NUMBER

Not applicable.

Evaluation and preservation of fertility in patients with hematologic malignancies

For patients with hematologic malignancies, novel therapeutic strategies offer the potential to achieve a complete clinical response and long-term survival. However, declining fertility has become a significant concern, impacting long-term quality of life. Conventional high-dose chemotherapy and radiotherapy are known to reduce fertility or cause sterility. Moreover, limited clinical data are available on the effects of newer therapies, such as targeted treatments and chimeric antigen receptor (CAR)-T cell therapy, on fertility. Additionally, there is no standard method for preserving fertility in these patients. Male patients can opt for sperm cryopreservation, whereas female patients may preserve fertility through embryo, oocyte, or ovarian tissue cryopreservation. However, preserving fertility in prepubescent patients remains particularly challenging. Therefore, hematologists must educate patients about the potential gonadal toxicity of cancer treatments and offer the most appropriate fertility preservation options.

Single-cell transcriptomic atlas of the human testis across the reproductive lifespan

Testicular aging is associated with declining reproductive health, but the molecular mechanisms are unclear. Here we generate a dataset of 214,369 single-cell transcriptomes from testicular cells of 35 individuals aged 21-69, offering a resource for studying testicular aging and physiology. Machine learning analysis reveals a stronger aging response in somatic cells compared to germ cells. Two waves of aging-related changes are identified: the first in peritubular cells of donors in their 30s, marked by increased basement membrane thickness, indicating a priming state for aging. In their 50s, testicular cells exhibit functional changes, including altered steroid metabolism in Leydig cells and immune responses in macrophages. Further analyses reveal the impact of body mass index on spermatogenic capacity as age progresses, particularly after age 45. Altogether, our findings illuminate molecular alterations during testis aging and their relationship with body mass index, providing a foundation for future research and offering potential diagnostic markers and therapeutic targets.

Non-human primate: the new frontier model of female reproductive engineering

Reproductive engineering encompasses a range of advanced tissue engineering techniques aimed at addressing infertility that is non-curable with current assisted reproductive technology (ART). The use of animal models has been crucial for these advancements, with a notable preference for non-human primates (NHPs) given their genetic, anatomical, and physiological similarities to humans. Therefore, NHPs are invaluable for studying reproductive engineering. Thus, in reproductive studies, NHPs bridge the anatomical and physiological gaps between rodent models and humans. Their shared features with humans, such as menstrual cycles, placentation, and hormonal regulation, allow for more accurate modeling of reproductive physiology and pathology. These traits make NHPs indispensable in the exploration of reproductive engineering, including infertility treatments, genetic engineering, and uterine transplantation. Reproductive engineering is a transformative field that addresses infertility and enhances reproductive health. By leveraging the unique traits of NHPs, researchers can deepen their understanding of reproductive processes and refine ART techniques for human use. Advances in genetic engineering have enabled the creation of transgenic NHP models, which have been used to modify genes to investigate roles for various purposes, and the process, as mentioned earlier, is closely related to the ART technique, including fertility, embryogenesis, and pregnancy. Therefore, the relation to reproductive studies and the necessity of the NHP model are prerequisites for reproductive engineering. The engineering of NHPs is critically related to integrating ethical practices and exploring complementary methodologies. This review overviews the types of NHP frequently used and studies using NHP for reproductive engineering. These studies may suggest a broader way to use NHP for reproductive engineering.

Exploring the heterogeneous targets of metabolic aging at single-cell resolution

Our limited understanding of metabolic aging poses major challenges to comprehending the diverse cellular alterations that contribute to age-related decline, and to devising targeted interventions. This review provides insights into the heterogeneous nature of cellular metabolism during aging and its response to interventions, with a specific focus on cellular heterogeneity and its implications. By synthesizing recent findings using single-cell approaches, we explored the vulnerabilities of distinct cell types and key metabolic pathways. Delving into the cell type-specific alterations underlying the efficacy of systemic interventions, we also discuss the complexity of integrating single-cell data and advocate for leveraging computational tools and artificial intelligence to harness the full potential of these data, develop effective strategies against metabolic aging, and promote healthy aging.

Zuogui pills ameliorate chemotherapy-induced ovarian aging by improving stemness, regulating cell cycle and reducing apoptosis of oogonial stem cells via the Notch1/Nrf2 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Zuogui Pills (ZGP) is a classic traditional Chinese herbal formula originating from the Ming Dynasty. It has been widely used in the treatment of kidney deficiency-related diseases, including ovarian aging.

AIM OF THE STUDY

To investigate the effects and potential mechanisms of ZGP on ovarian aging induced by the chemotherapeutic agent cyclophosphamide (CTX), as well as its impact on the therapeutic target, oogonial stem cells (OSCs), involving the Notch1/nuclear factor erythroid 2-related factor 2 (Nrf2) pathway.

MATERIALS AND METHODS

This study utilized High-Performance Liquid Chromatography (HPLC) to analyze the active components of Zuogui Pills (ZGP). In vivo experiments involved the establishment of an ovarian aging model in female rats through intraperitoneal injection of CTX, followed by an 8-week treatment with ZGP and dehydroepiandrosterone (DHEA). The Notch pathway inhibitor DAPT was administered via intraperitoneal injection, followed by ZGP intervention to validate its therapeutic effects. Transcriptomic sequencing was used to analyze the differential genes before and after ZGP treatment of CTX-induced ovarian aging, and KEGG and GO analyses were applied to assess the changes in relevant signaling pathways and biological processes. In vitro experiments included the extraction, separation, and purification of ovarian germ stem cells, followed by transfection with a Notch1 overexpression plasmid. The CTX active component 4-Hydroxycyclophosphamide (4HC) was used for model intervention, and ZGP, DHEA-containing serum, and DAPT were applied to intervene with the oogonial stem cells. The effects of CTX modeling, the therapeutic efficacy of ZGP, and the general condition of the rats were observed. H&E staining was employed to assess ovarian morphology and follicle counting at various stages. Serum hormone levels were measured using ELISA, while qPCR, Western blot, flow cytometry, immunofluorescence, and IHC were utilized to analyze the expression of the Notch1/Nrf2 pathway, cell cycle proteins, and stemness-related indicators. Flow cytometry, TUNEL fluorescence, and CCK8 assays were conducted to evaluate changes in cell cycle composition, apoptosis, and proliferation. Finally, ChIP-qPCR was employed to validate the transcriptional regulation of the target gene NFE2L2 by Notch1.

RESULTS

ZGP improved serum sex hormones in ovarian aging rats, enhanced ovarian index, and optimized ovarian and uterine morphology, as well as follicle quantity composition. After transcriptome sequencing, KEGG analysis enriched the Notch signaling pathway and cell cycle, while GO analysis highlighted enrichment in the Notch pathway and stem cell population maintenance. Various experiments validated that ZGP significantly improved the expression of cell cycle-related proteins Cyclin D1 (CCND1), Cyclin E1 (CCNE1), cyclin-dependent kinase inhibitor 1a (CDKN1A), stemness markers Mouse Vasa Homolog (MVH), Octamer-binding Transcription Factor 4 (Oct4), Fragilis, 5-Bromo-2'-deoxyuridine (BrdU), as well as Notch1 and Nrf2 in aging ovarian tissues and OSCs. Additionally, ZGP promoted the proliferation of 4HC-damaged OSCs, optimized OSCs cell cycle composition, reduced G0/G1 phase arrest, and decreased early and late apoptosis. ZGP could reverse the detrimental effects on stemness and cell cycle of OSCs caused by blocking the Notch pathway. Furthermore, ZGP may activate the regulation of its target gene NFE2L2 by upregulating Notch1 expression in OSCs, thereby exerting therapeutic effects.

CONCLUSION

ZGP protects ovarian function in CTX-induced ovarian aging rats by regulating the Notch1/Nrf2 pathway. It restores serum sex hormone levels, maintains normal follicle development, promotes the proliferation of aged OSCs, optimizes the cell cycle, reduces apoptosis, and preserves stemness, thereby alleviating ovarian aging.

Perspectives on biomarkers of reproductive aging for fertility and beyond

Reproductive aging, spanning an age-related functional decline in the female and male reproductive systems, compromises fertility and leads to a range of health complications. In this Perspective, we first introduce a comprehensive framework for biomarkers applicable in clinical settings and discuss the existing repertoire of biomarkers used in practice. These encompass functional, imaging-based and biofluid-based biomarkers, all of which reflect the physiological characteristics of reproductive aging and help to determine the reproductive biological age. Next, we delve into the molecular alterations associated with aging in the reproductive system, highlighting the gap between these changes and their potential as biomarkers. Finally, to enhance the precision and practicality of assessing reproductive aging, we suggest adopting cutting-edge technologies for identifying new biomarkers and conducting thorough validations in population studies before clinical applications. These advancements will foster improved comprehension, prognosis and treatment of subfertility, thereby increasing chances of preserving reproductive health and resilience in populations of advanced age.

Spatial transcriptomic landscape unveils immunoglobin-associated senescence as a hallmark of aging

To systematically characterize the loss of tissue integrity and organ dysfunction resulting from aging, we produced an in-depth spatial transcriptomic profile of nine tissues in male mice during aging. We showed that senescence-sensitive spots (SSSs) colocalized with elevated entropy in organizational structure and that the aggregation of immunoglobulin-expressing cells is a characteristic feature of the microenvironment surrounding SSSs. Immunoglobulin G (IgG) accumulated across the aged tissues in both male and female mice, and a similar phenomenon was observed in human tissues, suggesting the potential of the abnormal elevation of immunoglobulins as an evolutionarily conserved feature in aging. Furthermore, we observed that IgG could induce a pro-senescent state in macrophages and microglia, thereby exacerbating tissue aging, and that targeted reduction of IgG mitigated aging across various tissues in male mice. This study provides a high-resolution spatial depiction of aging and indicates the pivotal role of immunoglobulin-associated senescence during the aging process.

Trehalose Alleviates D-Galactose-Induced Aging-Related Granulosa Cell Death in Ovaries

Ovarian dysfunction caused by aging restricts female reproductive capacity and is accompanied by oxidative stress and impaired autophagy. Recent studies have shown that trehalose (Tre) can activate autophagy and have antioxidant effects. However, whether Tre can be used to attenuate ovarian aging remains unclear. Therefore, the anti-aging effects of Tre on the ovary were explored both in vivo and in vitro. D-galactose (D-gal) was administered i.p. daily (200 mg/kg body weight) for 8 weeks to establish the mouse ovarian aging model (n = 10). We found that Tre significantly reversed ovarian weight loss and reduced the number of TUNEL-positive granulosa cells caused by D-gal in mouse ovaries. Tre elevated the protein expression levels of LC3-II, Parkin, PINK1, Beclin1, and LAMP2 in ovaries. Mitochondrial-related proteins TOM20 and COX IV expression levels were increased by Tre administration. In vitro studies further supported these findings, showing that Tre treatment significantly reduced the number of SA-β-gal and PI-positive cells, and decreased ROS levels in cultured granulosa cells. Thus, Tre alleviates ovarian aging by activating mitophagy and reducing oxidative stress, suggesting its potential as an anti-aging agent for ovarian health.

Metformin decelerates aging clock in male monkeys

In a rigorous 40-month study, we evaluated the geroprotective effects of metformin on adult male cynomolgus monkeys, addressing a gap in primate aging research. The study encompassed a comprehensive suite of physiological, imaging, histological, and molecular evaluations, substantiating metformin's influence on delaying age-related phenotypes at the organismal level. Specifically, we leveraged pan-tissue transcriptomics, DNA methylomics, plasma proteomics, and metabolomics to develop innovative monkey aging clocks and applied these to gauge metformin's effects on aging. The results highlighted a significant slowing of aging indicators, notably a roughly 6-year regression in brain aging. Metformin exerts a substantial neuroprotective effect, preserving brain structure and enhancing cognitive ability. The geroprotective effects on primate neurons were partially mediated by the activation of Nrf2, a transcription factor with anti-oxidative capabilities. Our research pioneers the systemic reduction of multi-dimensional biological age in primates through metformin, paving the way for advancing pharmaceutical strategies against human aging.

CRISPR screening uncovers nucleolar RPL22 as a heterochromatin destabilizer and senescence driver

Dysfunction of the ribosome manifests during cellular senescence and contributes to tissue aging, functional decline, and development of aging-related disorders in ways that have remained enigmatic. Here, we conducted a comprehensive CRISPR-based loss-of-function (LOF) screen of ribosome-associated genes (RAGs) in human mesenchymal progenitor cells (hMPCs). Through this approach, we identified ribosomal protein L22 (RPL22) as the foremost RAG whose deficiency mitigates the effects of cellular senescence. Consequently, absence of RPL22 delays hMPCs from becoming senescent, while an excess of RPL22 accelerates the senescence process. Mechanistically, we found in senescent hMPCs, RPL22 accumulates within the nucleolus. This accumulation triggers a cascade of events, including heterochromatin decompaction with concomitant degradation of key heterochromatin proteins, specifically heterochromatin protein 1γ (HP1γ) and heterochromatin protein KRAB-associated protein 1 (KAP1). Subsequently, RPL22-dependent breakdown of heterochromatin stimulates the transcription of ribosomal RNAs (rRNAs), triggering cellular senescence. In summary, our findings unveil a novel role for nucleolar RPL22 as a destabilizer of heterochromatin and a driver of cellular senescence, shedding new light on the intricate mechanisms underlying the aging process.

Chromosome Segregation-1-like Gene Participates in Ferroptosis in Human Ovarian Granulosa Cells via Nucleocytoplasmic Transport

Premature ovarian insufficiency (POI) is defined as the depletion of ovarian function before the age of 40 years. The global prevalence of POI is 3.5%. To date, genetic factors account for 23.5% of the etiology of POI. Herein, a previously uncharacterized pathogenic homozygous variant of the chromosome segregation-1-like gene (CSE1L) was identified in POI patients via targeted panel sequencing. It is reported that dysregulated iron metabolism is involved in many reproductive endocrine disorders; however, its precise role in POI remains obscure. In this study, we identified CSE1L as a potential candidate gene that plays an important role in maintaining iron homeostasis. Deficiency of CSE1L led to ferroptosis in human granulosa cells, which was confirmed by transmission electron microscopy. Mechanistically, coimmunoprecipitation identified the direct interaction between CSE1L and FoxO1. Inhibition of CSE1L led to the excessive accumulation of FoxO1 in the nucleus via nucleocytoplasmic transport. Then, FoxO1 bound to the promoter region of NCOA4 and promoted its transcription, which was verified by a chromatin immunoprecipitation assay. Moreover, inhibition of CSE1L in cumulus cell monolayer could impede oocyte maturation, which might be associated with oxidative stress. Consequently, our study first revealed that CSE1L participated in ferroptosis in human ovarian granulosa cells via nucleocytoplasmic transportation, which might be helpful in revealing the molecular mechanism of CSE1L in the development of POI. Importantly, these findings might provide new insights into the application of ferroptosis inhibitors in the treatment of POI.

Targeting aging and age-related diseases with vaccines

Aging is a major risk factor for numerous chronic diseases. Vaccination offers a promising strategy to combat these age-related diseases by targeting specific antigens and inducing immune responses. Here, we provide a comprehensive overview of recent advances in vaccine-based interventions targeting these diseases, including Alzheimer's disease, type II diabetes, hypertension, abdominal aortic aneurysm, atherosclerosis, osteoarthritis, fibrosis and cancer, summarizing current approaches for identifying disease-associated antigens and inducing immune responses against these targets. Further, we reflect on the recent development of vaccines targeting senescent cells, as a strategy for more broadly targeting underlying causes of aging and associated pathologies. In addition to highlighting recent progress in these areas, we discuss important next steps to advance the therapeutic potential of these vaccines, including improving and robustly demonstrating efficacy in human clinical trials, as well as rigorously evaluating the safety and long-term effects of these vaccine strategies.

Multiomics insights into the female reproductive aging

The human female reproductive lifespan significantly diminishes with age, leading to decreased fertility, reduced fertility quality and endocrine function disorders. While many aspects of aging in general have been extensively documented, the precise mechanisms governing programmed aging in the female reproductive system remain elusive. Recent advancements in omics technologies and computational capabilities have facilitated the emergence of multiomics deep phenotyping. Through the application and refinement of various high-throughput omics methods, a substantial volume of omics data has been generated, deepening our comprehension of the pathogenesis and molecular underpinnings of reproductive aging. This review highlights current and emerging multiomics approaches for investigating female reproductive aging, encompassing genomics, epigenomics, transcriptomics, proteomics, metabolomics, and microbiomics. We elucidate their influence on fundamental cell biology and translational research in the context of reproductive aging, address the limitations and current challenges associated with multiomics studies, and offer a glimpse into future prospects.