bims-ginsta Biomed News
on Genome instability
Issue of 2025–06–15
eighteen papers selected by
Jinrong Hu, National University of Singapore



  1. Cell. 2025 Jun 05. pii: S0092-8674(25)00570-7. [Epub ahead of print]
      Mitochondrial abundance and genome are crucial for cellular function, with disruptions often associated with disease. However, methods to modulate these parameters for direct functional dissection remain limited. Here, we eliminate mitochondria from pluripotent stem cells (PSCs) by enforced mitophagy and show that PSCs survived for several days in culture without mitochondria. We then leverage enforced mitophagy to generate interspecies PSC fusions that harbor either human or non-human hominid (NHH) mitochondrial DNA (mtDNA). Comparative analyses indicate that human and NHH mtDNA are largely interchangeable in supporting pluripotency in these PSC fusions. However, species divergence between nuclear and mtDNA leads to subtle species-specific transcriptional and metabolic variations. By developing a transgenic enforced mitophagy approach, we further show that reducing mitochondrial abundance leads to delayed development in pre-implantation mouse embryos. Our study opens avenues for investigating the roles of mitochondria in development, disease, and interspecies biology.
    Keywords:  cell fusion; great apes; interspecies composite; interspecies hybrid; metabolism; mitochondria; mitophagy; mtDNA; pluripotent stem cells
    DOI:  https://doi.org/10.1016/j.cell.2025.05.020
  2. Nature. 2025 Jun 11.
      Although cell-fate specification is generally attributed to transcriptional regulation, emerging data also indicate a role for molecules linked with intermediary metabolism. For example, α-ketoglutarate (αKG), which fuels energy production and biosynthetic pathways in the tricarboxylic acid (TCA) cycle, is also a co-factor for chromatin-modifying enzymes1-3. Nevertheless, whether TCA-cycle metabolites regulate cell fate during tissue homeostasis and regeneration remains unclear. Here we show that TCA-cycle enzymes are expressed in the intestine in a heterogeneous manner, with components of the αKG dehydrogenase complex4-6 upregulated in the absorptive lineage and downregulated in the secretory lineage. Using genetically modified mouse models and organoids, we reveal that 2-oxoglutarate dehydrogenase (OGDH), the enzymatic subunit of the αKG dehydrogenase complex, has a dual, lineage-specific role. In the absorptive lineage, OGDH is upregulated by HNF4 transcription factors to maintain the bioenergetic and biosynthetic needs of enterocytes. In the secretory lineage, OGDH is downregulated through a process that, when modelled, increases the levels of αKG and stimulates the differentiation of secretory cells. Consistent with this, in mouse models of colitis with impaired differentiation and maturation of secretory cells, inhibition of OGDH or supplementation with αKG reversed these impairments and promoted tissue healing. Hence, OGDH dependency is lineage-specific, and its regulation helps to direct cell fate, offering insights for targeted therapies in regenerative medicine.
    DOI:  https://doi.org/10.1038/s41586-025-09097-6
  3. Nat Cardiovasc Res. 2025 Jun 10.
      Mechanisms of cell fate specification are central to developmental biology and regenerative medicine. ETV2 is a master regulator for the endothelial cell (EC) lineage specification. Here we study mechanisms by which ETV2 overexpression in human induced pluripotent stem-cell-derived mesodermal progenitors efficiently specifies ECs. We used CUT&RUN, scRNA-seq and scATAC-seq to characterize the molecular features of EC differentiation mediated by ETV2. We defined the scope of ETV2 pioneering activity and identified its direct downstream target genes. Induced ETV2 expression both directed specification of endothelial progenitors and suppressed acquisition of alternative fates. Functional screening and candidate validation revealed cofactors essential for efficient EC specification, including the transcriptional activator GABPA. Notably, the transcriptional repressor REST was also necessary for efficient EC specification. ETV2 recruited REST to repress non-EC lineage genes. Our study provides an unparalleled molecular analysis of EC specification at single-cell resolution and highlights the important role of pioneer factors to recruit repressors that suppress commitment to alternative lineages.
    DOI:  https://doi.org/10.1038/s44161-025-00660-y
  4. Adv Mater. 2025 Jun 09. e2500872
      Integrin α5β1 is crucial for cell attachment and migration in development and tissue regeneration, and α5β1 binding proteins can have considerable utility in regenerative medicine and next-generation therapeutics. We use computational protein design to create de novo α5β1-specific modulating miniprotein binders, called NeoNectins, that bind to and stabilize the open state of α5β1. When immobilized onto titanium surfaces and throughout 3D hydrogels, the NeoNectins outperform native fibronectin (FN) and RGD peptides in enhancing cell attachment and spreading, and NeoNectin-grafted titanium implants outperformed FN- and RGD-grafted implants in animal models in promoting tissue integration and bone growth. NeoNectins should be broadly applicable for tissue engineering and biomedicine.
    Keywords:  RGD; biomaterial; de novo protein design; hydrogel; integrin α5β1; regenerative medicine; titanium
    DOI:  https://doi.org/10.1002/adma.202500872
  5. Dev Cell. 2025 May 31. pii: S1534-5807(25)00320-X. [Epub ahead of print]
      Cell proliferation, which underlies tissue growth and homeostasis, requires high levels of metabolites such as deoxynucleotides (dNTPs). The dNTP pool is known to be tightly and cell-autonomously regulated via de novo synthesis and salvage pathways. In this study, we demonstrate that nucleotides can also be provided to cells non-autonomously by surrounding cells within a tissue. Using Drosophila epithelial tissues as models, we find that adult intestinal stem cells (ISCs) are highly sensitive to nucleotide depletion, whereas wing progenitor cells are not. Wing progenitor cells share nucleotides through gap junction connections, allowing buffering of replication stress induced by nucleotide pool depletion. Adult ISCs, however, lack gap junctions and cannot receive dNTPs from neighbors. Collectively, our data suggest that gap-junction-dependent sharing between cells can contribute to dNTP pool homeostasis in vivo. We propose that inherent differences in cellular gap junction permeability can influence sensitivity to fluctuations in intracellular dNTP levels.
    Keywords:  gap junctions; nucleotide homeostasis; replication stress; stem cells; tissue homeostasis
    DOI:  https://doi.org/10.1016/j.devcel.2025.05.009
  6. Trends Biochem Sci. 2025 Jun 11. pii: S0968-0004(25)00108-2. [Epub ahead of print]
      Cellular dormancy is characterized by a prolonged, reversible cell cycle arrest and absence of growth. Dormancy allows organisms to endure unfavorable environmental conditions and to maintain long-lived quiescent progenitor cells essential for tissue homeostasis and reproduction. Protein homeostasis (proteostasis) is central to the maintenance of intracellular integrity in all cell types, particularly in long-lived, non-dividing cells. Here we review adaptations to support proteostasis in dormant cells and highlight common themes of cellular dormancy across organisms, from yeast to adult quiescent stem cells. We also feature vertebrate oocytes as an emerging model of proteostasis during dormancy. Together, these comparisons reveal common and unique strategies to sustain proteostasis during dormancy, offering insights into how cells preserve function and viability over long quiescence periods.
    Keywords:  mTOR; protein aggregates; protein degradation; quiescence; ribosome biogenesis; translation
    DOI:  https://doi.org/10.1016/j.tibs.2025.05.004
  7. Curr Opin Genet Dev. 2025 Jun 06. pii: S0959-437X(25)00059-0. [Epub ahead of print]93 102367
      mRNA translation is rapidly upregulated after injury to supply proteins required for tissue regeneration. Augmented protein synthesis during regeneration has long been associated with increases in ribosome biogenesis and mTORC1 activity. Emerging evidence highlights the roles of multiple signaling pathways, RNA-binding proteins, and RNA modifications in tissue repair. Here, we review recent research on the molecular mechanisms underlying translational control in response to tissue damage. The findings underscore the importance of mRNA translation in regeneration and its potential therapeutic applications in tissue repair.
    DOI:  https://doi.org/10.1016/j.gde.2025.102367
  8. bioRxiv. 2025 May 28. pii: 2025.05.23.655122. [Epub ahead of print]
      1.The maintenance of centromere identity is essential for the proper segregation of chromosomes during cell division. Centromere identity is epigenetically specified by centromeric histone H3 variant CENP-A, and its retention during DNA replication is facilitated by HJURP chaperone. Replication stress disrupts replication fork progression and can negatively influence the interactions between histone chaperone network necessary for retention and deposition of parental and new histones, respectively. In this study we investigate the role of replication stress response on centromere inheritance. We define changes in centromere-associated proteins that govern stability of centromeric and canonical nucleosomes through proximity labeling coupled with affinity purification mass spectrometry. We identified that under replication stress, CENP-A-containing chromatin strongly enriches for SWI/SNF chromatin remodeling proteins ATRX. We show that depletion of ATRX and its associated histone H3.3 chaperone DAXX results in the loss CENP-A retention in S-phase and loss persists into the subsequent cell cycle. Altogether our findings provide insight into how replication stress negatively influences centromeric chromatin instability and delineates a function of DAXX-ATRX complex in maintaining centromere inheritance during DNA replication.
    DOI:  https://doi.org/10.1101/2025.05.23.655122
  9. Trends Cell Biol. 2025 Jun 09. pii: S0962-8924(25)00111-4. [Epub ahead of print]
      Concomitant progress in the fields of microfluidics, microscale molecular biology, next-generation sequencing, and analytical methods for whole transcriptomic datasets has transformed our ability to understand complex cellular state changes at the single-cell level. New cell types have been discovered and cell transition states and intermediate phenotypes have been characterized across diverse developmental and disease contexts. More recently, integrating transcriptomic and epigenomic data has dramatically extended our understanding of transcriptional regulons and gene regulatory networks (GRNs) that determine gene expression and individual cellular phenotypes. Applied to cardiac biology, combined transcriptomic and epigenomic profiling has allowed the characterization of the developmental trajectories and molecular mechanisms that give rise to the diverse cell lineages of the adult heart and contribute to the pathogenesis of genetic diseases. In this review, we present the latest methodological innovations, discuss the computational strategies for multiomic data integration, and highlight how these advances are reshaping our undestanding of heart development and disease mechanisms.
    Keywords:  cardiovascular; cell state; congenital heart disease; coronary artery disease; epigenomics; single cell; transcriptomics
    DOI:  https://doi.org/10.1016/j.tcb.2025.05.001
  10. Circulation. 2025 Jun 10. 151(23): 1667-1685
       BACKGROUND: Cardiac hypertrophy, as an important pathological change, contributes to heart failure. Recent studies indicate that the mitochondria-associated endoplasmic reticulum membranes (MAMs) play key roles in this pathological process. However, the molecular mechanism remains unclear. This study aims to elucidate the effects and mechanisms of MAM-resident FMO2 (flavin-containing monooxygenase 2) in cardiac hypertrophy and heart failure.
    METHODS: We performed bulk RNA-sequencing analysis using heart tissue from patients with cardiac hypertrophy and carried out MAM-targeted mass spectrometry analysis using heart tissue from a mouse model of pathological cardiac hypertrophy. In vitro cell culture using neonatal rat cardiomyocytes was used to study how MAMs formation affected cardiomyocyte functions. By generating different genetic mouse models combined with using adeno-associated virus 9 under the cardiac troponin T promoter techniques, we further investigated and confirmed the effects of MAM structure changes on cardiac hypertrophy.
    RESULTS: We detected an unexpected component of MAMs structure, which was the FMO2, an endoplasmic reticulum-resident protein. FMO2 levels decreased during pathological cardiac hypertrophy. The deletion and overexpression of FMO2 can either worsen or prevent the pathological heart failure progression in vivo, respectively. Our data further demonstrated that FMO2 localizes to MAM structure, where it binds to inositol 1,4,5-trisphosphate type 2 receptor (IP3R2) as a component of the IP3R2-Grp75 (glucose-regulated protein 75)-VDAC1 (voltage-dependent anion channel protein 1) complex, maintaining endoplasmic reticulum-mitochondria contact and regulating mitochondrial Ca2+ signaling for bioenergetics. Last, we showed that a synthetic peptide-enhancing endoplasmic reticulum-mitochondria contact promoted Ca2+ transfer and prevented pathological cardiac hypertrophy.
    CONCLUSIONS: Our findings reveal a key role of FMO2 in myocardial hypertrophy and that FMO2 plays a pivotal role in maintaining MAM structure and function, which may represent a novel mechanism and therapeutic target for cardiac hypertrophy and heart failure.
    Keywords:  hypertrophy; mitochondria; mitochondria associated membranes
    DOI:  https://doi.org/10.1161/CIRCULATIONAHA.124.072661
  11. Cell Rep. 2025 Jun 10. pii: S2211-1247(25)00587-X. [Epub ahead of print]44(6): 115816
      We report a multi-omics study in a human cell line with mutations in three subunits of origin-recognition complex (ORC). Although the ORC subunits should bind DNA as part of a common six-subunit ORC, there are thousands of sites in the genome where one subunit binds but not another. DNA-bound ORC2 compacts chromatin and attracts repressive histone marks to focal areas of the genome, but ORC2 also activates chromatin at many sites and protects the genes from repressive marks. These epigenetic changes regulate hundreds of genes, including some epigenetic regulators, adding an indirect mechanism by which ORC2 regulates epigenetics without local binding. DNA-bound ORC2 also prevents the acquisition of CTCF at focal sites in the genome to regulate chromatin loops and indirectly affect epigenetics. Thus, individual ORC subunits may bind to DNA to act as epigenetic and chromosome structure regulators independent of the role of the six-subunit ORC in DNA replication.
    Keywords:  CP: Genomics; CP: Molecular biology; CTCF; DNA replication; Hi-C; ORC; epigenetics; gene regulation; genomics; higher-order chromatin organization; histone modifications; origin-recognition complex
    DOI:  https://doi.org/10.1016/j.celrep.2025.115816
  12. Elife. 2025 Jun 13. pii: RP100497. [Epub ahead of print]13
      Breast carcinoma amplified sequence 2 (BCAS2), a core component of the hPrP19 complex, plays crucial roles in various physiological and pathological processes. However, whether BCAS2 has functions other than being a key RNA-splicing regulator within the nucleus remains unknown. Here, we show that BCAS2 is essential for primitive hematopoiesis in zebrafish and mouse embryos. The activation of Wnt/β-catenin signaling, which is required for hematopoietic progenitor differentiation, is significantly decreased upon depletion of bcas2 in zebrafish embryos and mouse embryonic fibroblasts. Interestingly, BCAS2 deficiency has no obvious impact on the splicing efficiency of β-catenin pre-mRNA, while significantly attenuating β-catenin nuclear accumulation. Moreover, we find that BCAS2 directly binds to β-catenin via its coiled-coil domains, thereby sequestering β-catenin within the nucleus. Thus, our results uncover a previously unknown function of BCAS2 in promoting Wnt signaling by enhancing β-catenin nuclear retention during primitive hematopoiesis.
    Keywords:  BCAS2; Wnt/β-catenin; coiled-coil domain; developmental biology; mouse; nuclear retention; primitive hematopoiesis; zebrafish
    DOI:  https://doi.org/10.7554/eLife.100497
  13. Nat Commun. 2025 Jun 06. 16(1): 5266
      Post-translational modifications (PTMs) regulate protein homeostasis, but how aging impacts PTMs remains unclear. Here, we used mass spectrometry to reveal changes in hundreds of protein ubiquitylation, acetylation, and phosphorylation sites in the mouse aging brain. We show that aging has a major impact on protein ubiquitylation. 29% of the quantified ubiquitylation sites were affected independently of protein abundance, indicating altered PTM stoichiometry. Using iPSC-derived neurons, we estimated that 35% of ubiquitylation changes observed in the aged brain can be attributed to reduced proteasome activity. Finally, we tested whether protein ubiquitylation in the brain can be influenced by dietary intervention. We found that one cycle of dietary restriction and re-feeding modifies the brain ubiquitylome, rescuing some but exacerbating other ubiquitylation changes observed in old brains. Our findings reveal an age-dependent ubiquitylation signature modifiable by dietary intervention, providing insights into mechanisms of protein homeostasis impairment and highlighting potential biomarkers of brain aging.
    DOI:  https://doi.org/10.1038/s41467-025-60542-6
  14. Sci Adv. 2025 Jun 13. 11(24): eadu4523
      Adult neural stem cells exist on a continuum from deep to shallow quiescence that changes in response to injury or aging; however, the transcription factors controlling these stepwise transitions have not been identified. Single-cell transcriptomic analyses of mice with loss of function or increased levels of the essential activation factor Ascl1 reveal that Ascl1 promotes the activation of hippocampal neural stem cells by driving these cells out of deep quiescence, despite its low protein expression in this state. Subsequently, during the transition from deep to shallow quiescence, Ascl1 induces the expression of Mycn, which drives progression through shallow quiescent states toward a proliferating state. Together, these results define the required sequence of transcription factors during hippocampal neural stem cell activation and establish a combinatorial code for classifying these cells into deep and shallow quiescence.
    DOI:  https://doi.org/10.1126/sciadv.adu4523
  15. bioRxiv. 2025 Jun 07. pii: 2025.06.07.658391. [Epub ahead of print]
      A Wnt activity gradient is essential for the formation of the anterior-posterior (AP) axis in all vertebrates. The relationship between the dynamics of Wnt signaling and specification of AP coordinates is difficult to study in mammalian embryos due to the inaccessibility of developing embryos and the difficulty of live imaging. Here, we developed an in vitro model of human neuroectoderm patterning, where the anterior-posterior axis self-organizes along the radius of a micropatterned human pluripotent stem cell colony. We used this system to study the quantitative relationship between Wnt signaling in space and time and the resulting AP patterns. We found that rather than a smoothly varying gradient along the axis, signaling is elevated in midbrain compared to either surrounding region. The timing, rather than the amplitude or duration, of the Wnt response played the most important role in setting axial coordinates. These results establish a simple system for studying the patterning of the human nervous system and elucidate how cells interpret Wnt dynamics to determine their position along the AP axis.
    DOI:  https://doi.org/10.1101/2025.06.07.658391
  16. bioRxiv. 2025 Jun 02. pii: 2024.06.14.599122. [Epub ahead of print]
      Diploid human cells contain two non-identical genomes, and differences in their regulation underlie human development and disease. We present Fiber-seq Inferred Regulatory Elements (FIRE) and show that FIRE provides a more comprehensive and quantitative snapshot of the accessible chromatin landscape across the 6 Gbp diploid human genome, overcoming previously known and unknown biases afflicting our existing regulatory element catalog. FIRE provides a comprehensive genome-wide map of haplotype-selective chromatin accessibility (HSCA), exposing novel imprinted elements that lack underlying parent-of-origin CpG methylation differences, common and rare genetic variants that disrupt gene regulatory patterns, gene regulatory modules that enable genes to escape X chromosome inactivation, and autosomal mitotically stable somatic epimutations. We find that the human leukocyte antigen (HLA) locus harbors the most HSCA in immune cells, and we resolve the specific transcription factor (TF) binding events disrupted by disease-associated variants within the HLA locus. Finally, we demonstrate that the regulatory landscape of a cell is littered with autosomal somatic epimutations that are propagated by clonal expansions to create mitotically stable and non-genetically deterministic chromatin alterations.
    DOI:  https://doi.org/10.1101/2024.06.14.599122
  17. Nature. 2025 Jun 11.
      Despite the success of fructose as a low-cost food additive, epidemiological evidence suggests that high fructose consumption during pregnancy or adolescence is associated with disrupted neurodevelopment1-3. An essential step in appropriate mammalian neurodevelopment is the phagocytic elimination of newly formed neurons by microglia, the resident professional phagocyte of the central nervous system4. Whether high fructose consumption in early life affects microglial phagocytosis and whether this directly affects neurodevelopment remains unknown. Here we show that offspring born to female mice fed a high-fructose diet and neonates exposed to high fructose exhibit decreased phagocytic activity in vivo. Notably, deletion of the high-affinity fructose transporter GLUT5 (also known as SLC2A5) in neonatal microglia completely reversed microglia phagocytic dysfunction, suggesting that high fructose directly affects neonatal development by suppressing microglial phagocytosis. Mechanistically, we found that high-fructose treatment of mouse and human microglia suppresses phagocytosis capacity, which is rescued in GLUT5-deficient microglia. Additionally, we found that high fructose drives significant GLUT5-dependent fructose uptake and catabolism to fructose 6-phosphate, rewiring microglial metabolism towards a hypo-phagocytic state in part by enforcing mitochondrial localization of the enzyme hexokinase 2. Mice exposed to high fructose as neonates develop anxiety-like behaviour as adolescents-an effect that is rescued in GLUT5-deficient mice. Our findings provide a mechanistic explanation for the epidemiological observation that high-fructose exposure during early life is associated with increased prevalence of adolescent anxiety disorders.
    DOI:  https://doi.org/10.1038/s41586-025-09098-5
  18. Dev Cell. 2025 May 30. pii: S1534-5807(25)00319-3. [Epub ahead of print]
      Mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) integrates diverse growth signals to regulate cell and tissue growth. How the molecular mechanisms regulating mTORC1 signaling-established through biochemical and cell biological studies-function under physiological states in specific mammalian tissues is undefined. Here, we characterize a genetic mouse model lacking the five phosphorylation sites on the tuberous sclerosis complex 2 (TSC2) protein through which the growth factor-stimulated protein kinase AKT can activate mTORC1 signaling in cell culture models. These phospho-mutant mice (TSC2-5A) are developmentally normal but exhibit reduced body weight and the weight of specific organs, such as the brain and skeletal muscle, associated with cell-intrinsic decreases in growth factor-stimulated mTORC1 signaling. The TSC2-5A mice demonstrate that TSC2 phosphorylation is a primary mechanism of mTORC1 regulation in response to exogenous signals in some, but not all, tissues and provide a genetic tool to study the physiological regulation of mTORC1.
    Keywords:  PI3K; RHEB; feeding; insulin; lean mass; lysosome; microcephaly; myotubes; neurons; phosphoinositide 3-kinase
    DOI:  https://doi.org/10.1016/j.devcel.2025.05.008