bims-ovagas Biomed News
on Ovarian aging and cGAS
Issue of 2026–07–19
ten papers selected by
Haiyuan Mu, University of California Berkeley



  1. Hum Reprod Update. 2026 Jul 17. pii: dmag018. [Epub ahead of print]
       BACKGROUND: With growing interest in ART, fertility preservation, and postmenopausal health of women, reproductive medicine is increasingly focused on characterizing oocytes and ovarian tissue composition, as well as understanding the molecular mechanisms that guide ovarian function throughout its lifecycle. High-throughput omics technologies have enabled the characterization of different molecular layers, leading to substantial advances in our understanding of their complex dynamics. However, not all molecular aspects are studied equally, and studies examining the same modalities often show inconsistencies, underscoring the need for data standardization and highlighting the potential for using transformative artificial intelligence and machine-learning (AI/ML) methods for ovary studies.
    OBJECTIVE AND RATIONALE: This study aims to evaluate how multi-omic studies have advanced our understanding of the ovarian lifecycle from fetal development to postmenopause. We systematically reviewed published studies that have investigated molecular/omic layers, including the genome, methylome, transcriptome, and proteome throughout ovarian development and aging. Our analysis identified key molecular and cellular patterns, highlighted inconsistencies across studies and addressed gaps in data analysis, interpretation, and reproducibility to guide future research.
    SEARCH METHODS: We conducted a systematic literature search of Medline (PubMed), Embase (Ovid), and Web of Science Core Collection (Clarivate) using a combination of controlled and free text terms for human ovary, oogenesis, folliculogenesis, ovary development and (epi)genome, transcriptome, proteome, and multi-omic mechanisms to find relevant articles published before August 2025. To focus the scope of the current review, studies of domesticated and farm animals, rodents and other model organisms, non-human primates, as well as those examining various human ovarian pathologies were excluded.
    OUTCOMES: The search identified 23 546 studies for screening, of which 637 full-text studies were assessed for eligibility. Subsequently, we extracted data from 121 studies. Most studies analyzed the transcriptome of oocytes, granulosa cells, and ovarian tissue from reproductive-age individuals (n = 91), with fewer studies examining samples from individuals of advanced reproductive age (n = 45) and fetal (n = 16) samples. Transcriptome analyses were most common (n = 103, 85%), followed by proteome (n = 19, 16%) and epigenome (n = 14, 12%) studies. We found substantial variation in how studies defined and reported participants' groups as well as in their sequencing technologies and data analysis methods, with a lack of standardized reporting of background clinical information, data analysis methods, and pipeline details. The key findings underscore the prevailing consensus on genes defining major ovarian cell types and their roles throughout the ovarian lifespan, from prenatal development to postmenopausal transformation. This review highlighted the underrepresentation of certain patient groups, particularly prepubertal and peri-/postmenopausal individuals, among researched populations, due to obvious clinical and ethical reasons.
    WIDER IMPLICATIONS: This scoping review offers a comprehensive overview and benchmark of the current state of high-throughput omics-based research on ovarian cellular composition and molecular dynamics. To address these shortcomings, we propose general recommendations for multi-omics ovary studies and emphasize the necessity for more thorough multi-omic data integration by effectively applying novel AI/ML approaches. They can potentially improve the quality of multi-omics analyses at both single-cell and tissue levels despite limited sample sizes and enable integration of molecular profiling data with clinical and radiology datasets, enabling a more comprehensive understanding of ovarian biology. Such advancements can enhance reproducibility of research findings and guide future research to deepen our understanding of ovarian biology and ultimately support the development of medical technologies for better preserving fertility and alleviating infertility.
    REGISTRATION NUMBER: A protocol was published a priori on the Open Science Framework (https://osf.io/z38gb/).
    Keywords:  follicle development; genome; methylome; oocyte maturation; ovarian aging; ovarian development; ovarian multi-omics studies; postmenopause; proteome; transcriptome
    DOI:  https://doi.org/10.1093/humupd/dmag018
  2. Biol Reprod. 2026 Jul 16. pii: ioag149. [Epub ahead of print]
      Studies of ovarian health and aging rely on estimates of the ovarian reserve, i.e. the number of healthy ovarian follicles. We present a machine learning pipeline to classify preantral ovarian follicles in histology images from nonhuman primates. Ovarian tissue from 11 monkeys, were fixed, sectioned, stained, and imaged. A total of 7770 preantral follicles were manually annotated in 18 histology section images using a standardized protocol, with annotations reviewed by an expert. Using a transfer learning approach, we retrained a ResNet34 convolutional neural network to classify individual follicle images into six developmental stages. The model achieved high accuracy during training (>98%) and good performance on validation and test sets (75.3% and 72.4%, respectively), with most errors confined to adjacent stages, suggesting the network learned an implicit developmental ordering of follicles. All code, annotated datasets, and trained models are publicly available to support reuse and further exploration. Application of this model for determining follicle numbers will be useful in studies of primates, and perhaps humans. For example, it may be used for determining drug or environmental toxicant effects on follicle populations or for fertility preservation planning. Importantly, this model will facilitate the study of ovarian aging and follicle depletion in a translational animal model and for developing interventions to preserve ovarian reserve, extend fertility, and delay menopause in women.
    Keywords:  convolutional neural network (CNN); follicle stage; machine learning; non-human primate; ovarian follicle; whole-slide imaging segmentation
    DOI:  https://doi.org/10.1093/biolre/ioag149
  3. Aging Cell. 2026 Jul;25(7): e70623
      Premature ovarian insufficiency (POI) is a major driver of female reproductive aging, but its mechanisms and the spatial and structural patterns of reproductive aging remain poorly understood. This study, therefore, constructed a spatial transcriptomic atlas of POI mouse models to define the spatial and molecular features of granulosa senescence during disease progression. Spatial analysis revealed disrupted follicular structure and distinct granulosa subpopulations exhibiting blocked differentiation and senescence-associated gene signatures. Integrating multiple gene sets identified structural and functional mitochondrial impairment, excess fission, reduced fusion, mitochondrial membrane potential loss, insufficient ATP production, and reactive oxygen species accumulation as central features of granulosa senescence in POI. KEGG pathway enrichment implicated FOXO signaling in regulating mitochondrial dysfunction, and FOXO3 phosphorylation was significantly reduced in POI. In a triptolide-induced KGN cell POI model, pharmacological inhibition of aberrant FOXO3 activation partially restored mitochondrial morphology and function, whereas suppressing FOXO3 phosphorylation in normal KGN cells induced mitochondrial dysfunction. AAV-mediated FOXO3 overexpression in mouse granulosa cells recapitulated the senescent phenotype and mitochondrial dynamic imbalance, activating PINK1/PARKIN-mediated mitophagy signaling. Physiologically aged 10-month-old mouse ovaries showed identical hallmarks-reduced p-FOXO3, upregulated senescence markers, and disrupted mitochondrial dynamics-suggesting a conserved feature of ovarian functional decline. Together, these findings demonstrate that aberrant FOXO3 pathway activation disrupts mitochondrial dynamic homeostasis, driving granulosa senescence and ovarian failure in POI. By integrating spatial transcriptomics with functional and mechanistic analyzes, this study establishes a spatially resolved framework for understanding ovarian aging and identifies FOXO3-regulated mitochondrial pathways as potential diagnostic and therapeutic targets for POI.
    Keywords:  FOXO3; granulosa cells; mitochondria; premature ovarian insufficiency; spatial transcriptomics
    DOI:  https://doi.org/10.1111/acel.70623
  4. Reprod Fertil. 2026 Jul 08. pii: RAF-25-0158. [Epub ahead of print]
       ABSTRACT: The in vitro culture of immature follicles remains a challenge in reproductive biology, ART, and fertility preservation. This study investigated the impact of α-MEM and SAGE 1-Step media on mouse preantral follicle development and oocyte maturation using two-dimensional (2D) and suspension culture systems. Preantral follicles (∼130 µm) from 14-day-old NMRI mice were cultured for 13 days in either medium under 2D or suspension conditions. On day 13, hCG was added to induce meiotic resumption. We evaluated follicular growth, antrum formation, oocyte maturation, meiotic spindle organization, and expression of genes related to maturation (Bmp15, Gdf9), cumulus expansion (Has2, Ptgs2, Lhr, Adamts1), and apoptosis (Bax, Bcl2). Antral formation was higher in α-MEM in both culture systems (P > 0.05). However, SAGE 1-Step significantly improved oocyte maturation across both systems (P =0.01 in 2D vs. P=0.006 in suspension compared to α-MEM). Spindle staining demonstrated that suspension culture significantly increased the percentage of oocytes with normal meiotic spindle organization (P=0.002). Gene expression analysis revealed a significant upregulation of Adamts1 (P=0.008) and downregulation of Bax (P=0.01) in suspension culture. Furthermore, the apoptotic ratio of Bax/Bcl2 was significantly decreased in the suspension system (P=0.01). In conclusion, SAGE 1-Step medium significantly enhances oocyte maturation, while the suspension system superiorly preserves meiotic spindle architecture and reduces apoptosis. The combination of SAGE 1-Step and suspension culture provides an optimized microenvironment for producing high-quality oocytes.
    LAY SUMMARY: Growing immature egg outside the body, a process known as in vitro follicle culture, is a promising but challenging technique for preserving fertility. This study investigated novel approaches to improve this process, aiming to create healthier, more viable eggs for future use. The researchers found that using a specific medium, significantly improved egg development and maturation. Importantly, they found that culturing these immature eggs in suspension, where the follicles remained floating in the medium, rather than in a traditional two-dimensional system where follicles inevitably flatten and partially lose their three-dimensional structure, resulted in significantly better outcomes. Eggs grown in suspension showed more organized cellular structures and reduced cell death compared to those cultured on a flat surface. These fundings represent an important step toward reliably producing healthy, developmentally competent eggs outside the body, offering new hope for fertility preservation and assisted reproduction. Advancing fertility preservation: a specific medium suspension culture dramatically boosts immature oocyte quality in the lab.
    Keywords:   In vitro maturation (IVM); Culture media; Folliculogenesis; Mouse ovarian follicle; Oocyte maturation; Three-dimensional (3D) culture
    DOI:  https://doi.org/10.1530/RAF-25-0158
  5. J Immunol. 2026 Jul 10. pii: vkag153. [Epub ahead of print]215(7):
      The mammalian ovary is the dynamic end-organ of the hypothalamic-pituitary-ovarian axis. In this coordinated system, ovarian cells undergo continuous cycles of apoptosis, proliferation, and differentiation. These changes parallel fluctuations in ovarian hormones such as estradiol; however, the ovarian immune microenvironment during high- and low-estradiol states remains incompletely defined. We induced a high-estradiol state in the mouse ovary by gonadotropin stimulation. Single-cell RNA sequencing and flow cytometry of ovarian leukocytes revealed abundant mature NK cells, B1 and B2 cells, CD8+ T cells, CD4+ T cells, mature CD4-CD8- T cells, T regulatory cells, and distinct myeloid subsets, including Trem2+ and Apoe+ macrophages. In vivo labeling of circulating cells indicated that the vast majority of ovarian leukocytes were tissue resident. Following gonadotropin treatment, the frequency of NK cells doubled, whereas that of B1 cells was reduced by half. Consistently, flow cytometry demonstrated an increase in mature CD11b+ NK cells after gonadotropin treatment. Cell-cell communication analysis further showed that gonadotropin treatment increased signaling by myeloid cells at the expense of NK cells. Collectively, these findings reveal a diverse, resident immune landscape in the ovary that responds robustly to hormonal changes, with implications for immune regulation in ovarian physiology and in pathological states.
    Keywords:  estrogen; natural killer cells; ovary
    DOI:  https://doi.org/10.1093/jimmun/vkag153
  6. Genes Dev. 2026 Jul 17.
      The bipotential gonad is the precursor to the ovary and testis. In mice, gonad differentiation is initiated by commitment of presupporting cells into testicular Sertoli cells or ovarian granulosa cells. While Sry drives testis differentiation, upstream drivers of ovary fate are unclear. We identified binding sites for basic helix-loop-helix (bHLH) transcription factors (TFs) upstream of granulosa genes and sought to investigate whether bHLH TFs regulate granulosa specification. bHLH transcription factor 4 (TCF4) was expressed in presupporting cells before sex determination. As development progressed, TCF4 was maintained in granulosa cells but lost in Sertoli cells. In Tcf4 STOP/STOP mutant mice lacking the TCF4 DNA-binding domain, FOXL2 was reduced in granulosa cells and nuclear morphology was altered. Mutant ovaries failed to undergo morphological changes similar to wild-type littermates. Meanwhile, Tcf4 STOP/STOP mutant testes appeared normal. We found that TCF4 binds the Mediator complex to regulate expression of gonadal genes (Wt1, Nr2f2) and granulosa-enriched genes including Jun and Fos In ex vivo gonad culture, inhibition of JUN activation led to decreased Wnt4 expression. These results support the hypothesis that TCF4 regulates an underlying gonadal program that primes the gonad toward a female fate and is silenced in Sertoli cells downstream from Sry.
    Keywords:  TCF4; development; gonad
    DOI:  https://doi.org/10.1101/gad.353245.125
  7. Dev Cell. 2026 Jul 17. pii: S1534-5807(26)00239-X. [Epub ahead of print]
      Fertilization involves dynamic sperm-egg interactions, yet has been primarily studied in static samples. Here, we use high-resolution live imaging to capture fertilization from the moment of sperm binding in zona-intact mouse oocytes. We identify two phases of sperm remodeling: a static phase, during which sperm remain beneath the oocyte cortex as DNA decondensation and histone loading occur, and a mobile phase characterized by stereotyped sperm movement. Initial displacement away from the spindle is driven by cytoplasmic streaming, with manipulations in mouse indicating that sperm movement requires chromatin decondensation and oocyte polarization. Subsequently, polar body cytokinesis generates convergent cortical flows that draw sperm toward the emerging female pronucleus. Finally, we capture sperm-egg fusion in human oocytes and characterize post-fusion events including meiotic resumption and sperm movement, offering a live-imaging description of human fertilization dynamics. Together, these findings provide a continuous spatiotemporal framework for mammalian fertilization, extended by initial observations in human oocytes.
    Keywords:  ICSI; IVF; chromatin remodeling; cortical flow; cytoplasmic streaming; fertilization; live imaging; oocyte; sperm; zygote
    DOI:  https://doi.org/10.1016/j.devcel.2026.06.015
  8. J Assist Reprod Genet. 2026 Jul 17.
      N6-methyladenosine (m6A), the dominant internal RNA modification in eukaryotic mRNA, plays an important regulatory role in female reproductive physiology and associated pathologies. This review systematically outlines the precise regulatory mechanisms exerted by m6A writers, erasers, and readers in core processes including germ cell development, early embryogenesis, and hormone signaling. We further elaborate on how aberrant m6A modifications contribute to the pathogenesis of various female reproductive disorders, such as gynecological cancer, polycystic ovary syndrome, and preeclampsia. In addition, we conducted a rigorous assessment of the therapeutic and diagnostic potential targeting the m6A mechanism. By synthesizing mechanistic insights from both neoplastic and non-neoplastic diseases, this review provides a comprehensive framework for understanding the epitranscriptomic governance of female reproductive health and proposes new directions for future research and clinical translation.
    Keywords:  Epigenetic modification; Female reproductive development; Female reproductive diseases; M6A detection technology; N6-methyladenosine (m6a); Treatment strategy
    DOI:  https://doi.org/10.1007/s10815-026-03953-8
  9. Nat Commun. 2026 Jul 17.
      During pregnancy mammals increase their food intake to accommodate the elevated metabolic demands associated with fetal growth and development. However, the molecular and neural circuit mechanisms mediating increased feeding during pregnancy are largely unknown. Here, we demonstrate that arcuate nucleus agouti-related peptide (AgRP) neurons are activated and pro-opiomelanocortin (POMC) neurons are inhibited during pregnancy in mice. These changes are acutely required for promoting hyperphagia during pregnancy as chemogenetic inhibition of AgRP neurons or activation of POMC neurons both reduced the feeding of pregnant mice to non-pregnant levels. Finally, we utilized single cell resolution spatial transcriptomics in the arcuate nucleus of non-pregnant and pregnant mice to characterize pregnancy-induced changes in the transcriptomic state of arcuate nucleus neurons, including significant changes in many neurons controlling energy homeostasis, including AgRP and POMC neurons. Together, these findings outline a circuit mechanism regulating increased feeding during pregnancy, providing important mechanistic insights related to conditions at the intersection of reproduction and metabolism.
    DOI:  https://doi.org/10.1038/s41467-026-75650-0
  10. bioRxiv. 2026 Jul 06. pii: 2026.07.03.736379. [Epub ahead of print]
      The maternal-to-zygotic transition (MZT) requires coordinated clearance and deadenylation of maternally deposited mRNAs, yet the underlying molecular mechanisms remain poorly understood. N6-methyladenosine (m 6 A) has emerged as a key regulator of maternal mRNA fate, but prior studies have relied on population-averaged short-read methods that cannot resolve modification state, poly(A) tail length, or isoform identity on the same molecule. Here, we employ nanopore direct RNA sequencing on zebrafish embryos across MZT to resolve the interplay between m 6 A deposition, mRNA clearance, and poly(A) tail length dynamics at single-molecule resolution. We find that 78% of expressed maternal genes harbor m 6 A-modified isoforms, significantly exceeding prior bulk estimates. Within-isoform comparisons demonstrate that m 6 A promotes mRNA decay, with CDS m 6 A contributing more to maternal mRNA clearance than 3'-UTR m 6 A. The positional context of m 6 A alone is sufficient to determine the temporal regulation of poly(A) tail lengths. CDS m 6 A constitutively suppresses tail length throughout MZT, while 3'-UTR m 6 A acquires shortening activity only after zygotic genome activation (ZGA). Transcriptomic analysis of ythdf2 knockout embryos reveals two unrecognized roles. Ythdf2 stabilizes m 6 A-marked maternal transcripts to set stoichiometry at MZT onset, and is also responsible for maintaining global poly(A) tail homeostasis prior to ZGA through an m 6 A-independent mechanism. Together, these findings define the single-molecule logic by which m 6 A modifications shape transcript fate during vertebrate MZT.
    DOI:  https://doi.org/10.64898/2026.07.03.736379