Aging Cell最新文献

Alzheimer's disease (AD) is a neurodegenerative disease characterized by amyloid-beta plaques and neurofibrillary tau tangles in the brain, neuroinflammation, and cognitive impairment. The 3xTg-AD mouse is a commonly used model in AD studies. 3xTg-AD males display inconsistent pathology; therefore, most studies utilize females. An understanding of why sexual dimorphism exists in this model is lacking. In humans, low circulating choline levels are associated with elevated AD pathology, while higher choline intake reduces pathology in AD mouse models. Here, we sought to understand if blood choline levels are associated with the sex discrepancies observed in 3xTg-AD mice. Body weight and chow consumption were measured, and blood plasma samples were collected at 3, 6, 9, 12 months of age and at end-point in 3xTg-AD and NonTg mice. 3xTg-AD females and NonTg males consumed more chow and gained more body weight than other groups. Longitudinally, 3xTg-AD mice had lower plasma choline levels than NonTg mice, while levels declined with age in NonTg mice. Female 3xTg-AD mice had higher AD-like pathological burden than males, but males had higher mortality rates across the study. IntelliCage automated phenotyping revealed high water-seeking behavior in males. 3xTg-AD mice displayed higher impulsivity compared to NonTg mice. Males were better at spatial and attention tasks but perseverated during avoidance testing compared with females. These findings demonstrate a persistent reduction in circulating choline levels across the lifespan of 3xTg-AD mice despite adequate dietary intake. Given choline's roles in metabolism, inflammatory regulation, and neuronal function, chronically low circulating choline may contribute to the various dysfunctions observed in this model.

A key characteristic of senescent and ageing cells is a reduction in number and increase in size of nucleoli. Although a number of pathways have been suggested, the mechanisms underlying this altered nucleolar phenotype, and the downstream consequences, remain poorly understood. The PolI complex component, TIF-IA, has previously been implicated in regulating this characteristic nucleolar phenotype in response to stress. Here we explored the role of TIF-IA in senescence and ageing. We show that TIF-IA accumulation, particularly in the nucleus and nucleolus, is an early response to oncogene- and therapy-induced senescence (OIS and TIS) in vitro. Using multiple mouse models, we also demonstrate accumulation of TIF-IA in response to senescence induction and ageing in vivo. We demonstrate that TIF-IA accumulation is not required for cell cycle arrest but that in OIS and TIS, it is essential for phenotypic changes to nucleoli, the senescence-associated secretory phenotype (SASP) and establishment of stable senescence. We demonstrate that in proliferating cells, TIF-IA binds the cargo receptor, p62 (SQSTM1), and that accumulation in senescence occurs as a consequence of ATM activation, which disrupts this interaction. Finally, we show that TIF-IA accumulation causes an increase in reactive oxygen species (ROS) levels. Together, these results establish TIF-IA accumulation as a key regulator of the nucleolar phenotype and the SASP in senescence and uncover a novel, p62-dependent mechanism driving this process. These findings offer significant new insights into nucleolar size regulation in senescence and ageing, and suggest a potential relationship with the inflammatory phenotype.

Ovarian somatic cells are essential for reproductive function, but no existing ex vivo models recapitulate the cellular heterogeneity or interactions within this compartment. We engineered an ovarian somatic organoid model by culturing a stroma-enriched fraction of mouse ovaries in scaffold-free agarose micromolds. Self-organized ovarian somatic organoids maintained diverse cell populations, produced extracellular matrix, and secreted hormones. Organoids generated from reproductively old mice exhibited reduced aggregation and growth compared to young counterparts, as well as differences in cellular composition. Interestingly, matrix fibroblasts from old mice demonstrated upregulation of pathways associated with the actin cytoskeleton and downregulation of cell adhesion pathways, indicative of increased cellular stiffness that may impair organoid aggregation. Cellular morphology, which is regulated by the cytoskeleton, significantly changed with age and in response to actin modulation. Moreover, actin modulation altered organoid aggregation efficiency. Overall, ovarian somatic organoids have advanced knowledge of cellular contributions to ovarian aging.

On October 22nd, 2025, Brain Aging Symposium took place at Harvard Medical School bringing together leading researchers from academia and partner organizations to discuss recent advances in measuring and monitoring human brain aging trajectories, with a particular focus on Alzheimer's disease (AD). A central theme emerged: achieving “the right treatment for the right person and the right time” through precision medicine approaches. Key advances included the unprecedented validation of plasma-based biomarkers, particularly brain-derived p-Tau217 that can identify seeding AD pathology with remarkable specificity, making large-scale screening newly feasible. Integrating multi-level “omic” modalities, spanning genetic information, molecular biomarkers of nutrition, lipid and protein signatures, neuroimaging measures, cognitive assessments, and lifestyle factors, enhances disease risk modeling and trajectory prediction beyond the capacity of any single marker. Early findings highlight critical roles for nutritional and lipid metabolism, and myelin integrity in brain aging, with cell and sex-specific vulnerabilities identified in response to nutrition, social isolation, and metabolic stress. Computational approaches that combine single-cell genomics, epigenomics, and artificial intelligence have been shown to accelerate causal discovery and therapeutic development. However, significant challenges remain: current biomarkers explain only half the variance in cognitive decline, racial and ethnic differences in biomarker levels lack mechanistic understanding, and scalable tools for comprehensive brain aging assessment are needed. The symposium underscored that preventing AD will require intervening during the preclinical asymptomatic phase. These multimodal screening platforms, coupled with mechanistically driven therapeutics, reduction in modifiable risk factors, including nutrition, vascular health, and social determinants of health, could profoundly impact the field.

The senescent cell (SC) fate is linked to aging, multiple disorders and diseases, and physical dysfunction. Senolytics, agents that selectively eliminate 30%–70% of SCs, act by transiently disabling the senescent cell antiapoptotic pathways (SCAPs), which defend those SCs that are proapoptotic and pro-inflammatory from their own senescence-associated secretory phenotype (SASP). Consistent with this, a JAK/STAT inhibitor, Ruxolitinib, which attenuates the pro-inflammatory SASP of senescent human preadipocytes, caused them to become “senolytic-resistant”. Administering senolytics to obese mice selectively decreased the abundance of the subset of SCs that is pro-inflammatory. In cell cultures, the 30%–70% of human senescent preadipocytes or human umbilical vein endothelial cells (HUVECs) that are senolytic-resistant (to Dasatinib or Quercetin, respectively) had increased p16^INK4a, p21^CIP1, senescence-associated β-galactosidase (SAβgal), γH2AX, and proliferative arrest similarly to the total SC population (comprising senolytic-sensitive plus-resistant SCs). However, the SASP of senolytic-resistant SCs entailed less pro-inflammatory/apoptotic factor production, induced less inflammation in non-senescent cells, and was equivalent or richer in growth/fibrotic factors. Senolytic-resistant SCs released less mitochondrial DNA (mtDNA) and more highly expressed the anti-inflammatory immune evasion signal, glycoprotein non-melanoma-B (GPNMB). Transplanting senolytic-resistant SCs intraperitoneally into younger mice caused less physical dysfunction than transplanting the total SC population. Because Ruxolitinib attenuates SC release of proapoptotic SASP factors, while pathogen-associated molecular pattern factors (PAMPs) can amplify the release of these factors rapidly (acting as “senosensitizers”), senolytic-resistant and senolytic-sensitive SCs appear to be interconvertible.

There is increasing evidence that nutrient composition, even without lowering total calorie intake, can shape lifespan through mechanisms independent of mitochondrial regulation. Brandon and colleagues recently reported that a low-protein, high-carbohydrate (LPHC) diet enriched with non-digestible cellulose, extends lifespan in mice by shifting the liver proteome through altered RNA splicing, a response different from the mitochondrial improvements typically seen with caloric restriction. The authors' findings support the “energy-splicing resilience axis,” which proposes that changes in splicing help cells adapt to energetic and nutritional stress. We discuss how diet influences spliceosomal components such as SRSF1, linking nutrient sensing, AMPK signaling, and tissue-specific resilience pathways. We also consider the splicing paradox in aging, where beneficial isoforms increase despite a concomitant increase in splicing errors. Understanding how dietary and pharmacologic interventions modulate splicing may shed light on strategies to maintain homeostatic proteomes and support healthy longevity.

Against the backdrop of the global trend toward delayed childbearing, elucidating the mechanisms underlying uterine aging has emerged as a critical biomedical priority for addressing age-related implantation failure. Through unbiased global metabolomic profiling of peri-implantation uteri across different ages in mice, we identified nicotinamide adenine dinucleotide (NAD⁺) depletion as a hallmark metabolic feature of endometrial aging. Single-cell RNA sequencing further revealed an expansion of senescent stromal cell populations, which was accompanied by a decline in NAD⁺ levels. Supplementation with NAD⁺ precursors alleviated age-related stromal senescence and endometrial dysfunction, thereby restoring the uterus' implantation competence. Mechanically, we demonstrate that CD38 derived from myeloid serves as a principal driver of uterine NAD⁺ depletion; this process accelerates stromal senescence and impairs uterine receptivity. These findings establish CD38 as a central physiological integrator that links NAD⁺ metabolism to uterine function and highlight it as a promising target for rejuvenation strategies aimed at improving reproductive outcomes in women of advanced maternal age.

Telomerase RNA (TERC) is subject to various modifications, yet the implications of these modifications for telomerase biology remain largely unexplored. In this study, we conducted a comprehensive mapping of N6-Methyladenosine (m6A) modifications within TERC RNA and elucidated their regulatory role in telomerase function. Our findings demonstrate that TERC undergoes methylation at adenosine residues A111 and A435 by METTL3. A deficiency in TERC m6A, which is also linked to various human telomerase disease-related mutations and deletions, significantly reduces telomerase activity and telomere length by disrupting the association between TERC and TERT. Mechanistically, YTHDC1 was identified as a scaffold facilitating the interaction between TERT and TERC, binding to TERT while recognizing m6A sites on TERC. Knockdown of YTHDC1 significantly diminished the interaction between TERT and TERC, thereby reducing telomerase activity and phenocopying the deficiency of METTL3. Furthermore, reconstituting wild-type YTHDC1 rescued telomere attrition, proliferation defects, and senescence in YTHDC1-knockdown alveolar epithelial cells, whereas truncated YTHDC1 (which retains m6A recognition but lacks TERT-binding capacity) failed to restore these phenotypes. Collectively, our work establishes m6A modification of TERC as a central regulator of telomerase function and reveals YTHDC1's scaffolding role in TERT-TERC assembly, shedding new light on the regulation of telomerase and related diseases.

Clinical evidence supports the anti-photoaging efficacy of 5-aminolevulinic acid photodynamic therapy (ALA-PDT), yet its mechanism remains elusive. Paradoxically, ALA-PDT generates reactive oxygen species (ROS), a key mediator of ultraviolet radiation (UVR)-induced photoaging, raising questions about its rejuvenating effects. Here, we employed a multi-omics approach to clarify this paradox. A UVR-induced hairless mouse model of photoaging was treated with ALA-PDT, followed by transcriptomic, proteomic, and metabolomic profiling of skin biopsies. In vitro, fibroblast senescence was induced by UV irradiation to evaluate ALA-PDT's protective effects. Mitochondrial function and citrate (CA) levels were assessed pre- and post-treatment. ALA-PDT significantly ameliorated photoaging phenotypes in mice, with multi-omics data revealing sustained improvements in epidermal structure, extracellular matrix integrity, and immune responses. Key mechanistic findings included ALA-PDT-induced mitohormesis and tricarboxylic acid cycle reprogramming, notably reduced intracellular CA. In vitro, low-dose ALA-PDT downregulated senescence markers and CA content in UV-stressed fibroblasts, concomitant with upregulated mitohormesis markers. These effects were abrogated by inhibiting mitochondrial ROS, suggesting ROS-dependent mitohormetic signaling. Collectively, our data demonstrate that low-dose ALA-PDT alleviates photoaging by mitigating cellular senescence via mitohormesis-mediated CA reduction, offering a novel metabolic intervention strategy for age-related skin disorders.

Aging is an inevitable consequence for all organisms. According to the mitochondrial free radical theory of aging (MFRTA), reactive oxygen species (ROS), which are predominantly generated in mitochondria, are assumed to play a key role. Calorie restriction (CR) delays aging by improving mitochondrial function; however, the molecular mechanisms underlying the effects of ROS and CR on mitochondria remain poorly understood. Oxidative protein modifications in mitochondrial proteins from the heart and cerebrum of young (6.5 months) and old (27 months) rats were quantified and the effects of short-term and lifelong CR interventions were investigated. Mass spectrometry was leveraged to achieve an unbiased and comprehensive analysis of various types of oxidative postranslational modifications (oxPTMs). Contrary to the MFRTA, aging did not cause significant increases in mitochondrial protein oxidation in the heart and cerebrum. CR markedly diminished the overall level of oxPTMs in the heart, particularly in transmembrane proteins. Similarly, the level of oxidative modification of transmembrane proteins in cerebrum was reduced by CR, whereas it perplexingly increased in mitochondrial proteins. The absolute level of oxidized mitochondrial protein was always higher in the heart than in the cerebrum under all conditions. Carbonylation, a prevalent marker of protein oxidation and aging, increased in the heart with age and was notably reduced by CR. However, this trend was not consistent in cerebrum or for some other types of oxPTMs. Therefore, protein oxidation in the heart and cerebrum exhibits distinct responses to chronological aging and dietary interventions, with the latter exerting a stronger influence.