Aging Cell

The dose-response of six months of controlled exercise was studied in 72 subjects aged 50 to 70 years, with 1-4 training sessions per week, focusing on DNA methylation-based aging. Epigenetic age reduction increased with exercise dose, with about 255 MET-hours aligning with a one-year decrease in Robust PhenoAge acceleration- a volume consistent with WHO physical activity guidelines. The finding that relative ventricular posterior wall thickness and muscular quotient change in tandem with Robust PhenoAge acceleration suggests that epigenetic clocks reflect genuine organ-level rejuvenation. The DNA methylation-based protein prediction identified TGF-aplha, TIMP1, and adrenomedullin as showing a dose-response relationship with exercise volume. The exercise intervention yielded systemic health benefits, improved some cardiac parameters measured by echocardiogram, increased HDL levels, lowered blood pressure, reduced android fat mass, and notably, enhanced physiological functions, including cognitive performance. The program increased the relative abundance of microbes supporting intestinal barrier integrity and decreased pro-inflammatory bacterial populations. Serum N-lactoyl-phenylalanine levels showed a downward trend after six months of exercise, while trimethylamine N-oxide levels rose in male participants. This single-arm exercise study identified a dose-response relationship between cumulative exercise dose and Robust PhenoAge or GrimAge acceleration, strengthening the evidence that the observed associations are attributable to exercise exposure rather than background factors or confounders. The results further support the idea that regular physical activity can influence biological age by improving cardiac structure and function, and indicate that PhenoAge and GrimAge effectively reflect age-related cardiac changes.

Microglial dysfunction is a hallmark of brain ageing linked to the accumulation of senescent microglial phenotypes that promote chronic neuroinflammation. Both genotoxic and metabolic stress have been implicated in microglial senescence; yet, whether distinct stressors shape senescence programs remain unclear. Here, we investigated the impact of chronic genotoxic and metabolic stress on senescence-associated phenotypes in the human microglia cell line HMC3. Cells were exposed to doxorubicin to induce sustained DNA damage or to chronic high-glucose conditions to model metabolic stress. Both stress paradigms induced characteristic senescence features including cellular and nuclear hypertrophy, increased senescence-associated {beta} galactosidase activity and reduced metabolic viability without significant cell loss. Both conditions activated the p53-p21 pathway and sustained DNA damage signalling, whereas metabolic stress additionally induced p16 expression and peripheral nuclear localisation of p21, suggesting divergence in senescence regulatory pathways. Mitochondrial alterations were evident under both conditions, Dox-induced stress was associated with downregulation of NRF2-TFAM signalling, whereas HG-induced stress induced NRF2-TFAM activation alongside increased KEAP1 expression, suggesting a constrained antioxidant response. This was accompanied by activation of mitochondrial and antioxidant stress responses that did not restore mitochondrial content. Furthermore, both stressors induced robust inflammatory activation, with genotoxic stress promoting a chemokine-rich senescence-associated secretory phenotype, while metabolic stress induced an interferon-associated inflammatory signature. Collectively, these findings demonstrated that chronic genotoxic and metabolic stress drive distinct yet overlapping senescence programs characterised by morphological changes, mitochondrial remodelling and persistent inflammatory activation. These stress-specific responses may differentially contribute to neurodegenerative processes and disease susceptibility.

Canine models are invaluable for translational geroscience, but widespread gonadectomy in companion dogs obscures natural sex-specific aging trajectories. Here, we characterize the age-associated hematologic and serum cytokine profiles of 80 intact laboratory Beagles spanning 1 to 11 years. Contrary to classical linear models of immunosenescence and inflammaging, we reveal that canine immune aging is highly dynamic and sexually dimorphic. While absolute leukocyte counts declined continuously, cytokine remodeling was sex-specific: intact males exhibited extensive age-dependent inflammatory restructuring, whereas females demonstrated restricted fluctuations. To establish baseline geroprotective signatures, we evaluated 24 young beagles following a 90-day intervention with rapamycin, canagliflozin, or dietary restriction. Rapamycin induced robust immune modulation, while canagliflozin prompted early, sex-biased weight loss and narrower cytokine responses. Together, our findings demonstrate that canine immune aging involves complex, sexually dimorphic remodeling. By utilizing an intact cohort to isolate natural dimorphic trajectories, we provide a crucial foundation for developing precision, sex-optimized geroprotectors.

Arteries are among the first tissues to exhibit age-related dysfunction, yet the metabolic mechanisms driving vascular senescence remain poorly understood. Here, analysis of human aortic transcriptomic data identified HCAR1, encoding the lactate receptor GPR81, as one of the genes most significantly downregulated with age. We therefore investigated whether age-associated loss of GPR81 contributes to cellular senescence within the vessel wall. Senescent human endothelial cells and vascular smooth muscle cells accumulated neutral and oxidized lipids and exhibited increased labile iron and ferroptosis. Silencing GPR81 in early-passage cells recapitulated this metabolic phenotype together with multiple hallmarks of cellular senescence. Moreover, endothelial-specific deletion of GPR81 in young mice was sufficient to induce senescent cell accumulation, impaired lipid homeostasis, endothelial dysfunction, and elastin disorganization. Conversely, pharmacological activation of GPR81 with the agonist CHBA restored fatty acid metabolism, promoted glycolytic reprogramming, and attenuated ferroptotic stress and senescence-associated phenotypes. In lamin A knock-in (LAKI) progeroid mice, CHBA reduced arterial lipid accumulation and cellular senescence, shifted vascular cell composition toward a youthful state, improved endothelial integrity, and restored extracellular matrix homeostasis. Together, these findings identify age-associated loss of GPR81 as a driver of vascular metabolic dysfunction and cellular senescence and establish pharmacological GPR81 activation as a promising therapeutic strategy for preserving vascular homeostasis and mitigating age-associated cardiovascular disease.

Tendons are commonly injured, not only in athletes, but also during normal everyday activities, particularly in older age. Tendons are rich in extracellular matrix proteins, many of which are turned over extremely slowly during an individuals lifetime. As a result, tight regulation of the extracellular matrix is essential for tendons to remain resilient to the mechanical load placed on them. However, tendons are prone to age-associated functional decline, characterised by chronic inflammation, accumulation of damaged collagen, and matrix remodelling. These degenerative changes often precede injury, wherein additional inflammation and fibrotic tissue deposition make treatment difficult and reinjury highly likely. Understanding and preventing the causes of tendon functional decline is therefore vital to improving quality of life in the ageing population. Using an equine model, here we show that tendon fibroblasts, or tenocytes, isolated from aged tendons exhibit markers of senescence when cultured in vitro. Further, we describe how senescence in tenocytes drives inflammation, hypercontractility, and dysregulation of tendon matrix components. By replicatively senescing tenocytes isolated from young tendons, we observed that senescent tenocytes instigated proinflammatory signalling, had impaired capacity in wound healing assays, increased contractility, and secreted factors that induced senescence in healthy tenocytes. Further, tenocyte senescence dysregulated matrix turnover both at the gene and protein level. Finally, we demonstrate how senotherapeutic treatment of senescent tenocytes can reduce expression of senescence markers and restore proliferative capacity. Our results uncover systemic links between tendon ageing and cellular senescence, and identify mechanisms and therapeutic strategies for age-associated tendon degeneration.

Aging disrupts neural function, but whether impaired noradrenergic control of brain metabolism contributes to functional decline remains unclear. Using genetically encoded fluorescent sensors we measured metabolic and signaling responses in neurons and glia of living Drosophila brains following stimulation with octopamine, the invertebrate analogue of noradrenaline. Aging was accompanied by neurodegeneration, reduced locomotion and enhanced oxidative whole-brain metabolism. Octopamine increased D-glucose uptake selectively in astrocytes and elevated L-lactate in both astrocytes and neurons, consistent with astrocytic glycolysis coupled to neuronal L-lactate uptake; monocarboxylate transporter inhibition caused selective astrocytic L-lactate accumulation. In aged animals octopamine-evoked metabolic responses in astrocytes and neural Ca2+ transients were markedly reduced. This impairment was associated with lower expression of adrenoceptor-like tyramine 1 receptor (Tyr1R). Selective Tyr1R overexpression in (nor)adrenergic-like Tdc2 neurons prolonged lifespan, restored Ca2+ signalling and improved locomotor performance. These findings identify Tyr1R-dependent Ca2+ signalling as an age-sensitive regulator of brain metabolism and motor function.

Osteoporosis is a highly prevalent age-related disorder, and accumulating evidence suggests that it does not arise in isolation but is intrinsically linked to the aging process. Here, we employed integrative methods to systematically identify the relationship between aging and osteoporosis, and uncover the critical cell types and molecular regulators that mediate this association. Observational analysis of phenotypic data from UK Biobank and Mendelian Randomization analysis of summary-level statistics revealed that aging and osteoporosis are interrelated, acting as both causes and effects of each other. We identified macrophages as the key cell types mediating this association by integration of GWAS data with a comprehensively assembled single-cell transcriptomic atlas of bone remodeling. And the percentage of macrophages from bone marrow decreases with age. Additionally, shared genetic tools and weight co-expression network analysis were employed to uncover novel molecular regulators underlying this crosstalk. We identified TGFB1 and a novel gene, HNRNPUL1, as key regulators that influence macrophages differentiation and function. In conclusion, our study provides observational and genetic evidence for a bidirectional relationship between aging and osteoporosis and unveils a macrophage-centric mechanism regulated by TGFB1 and HNRNPUL1, offering new insights for age-related bone loss.

Ribosomal DNA (rDNA) is a highly repetitive and complex locus within the mammalian genome that exhibits substantial inter-individual variation in number of rDNA copies and epigenetic regulation. Nonetheless, our understanding of rDNA biology in skeletal muscle during periods of physiological stress is limited. Using publicly available whole genome and reduced representative bisulfite sequencing data sets, we identify a concurrent reduction in both the number of rDNA copies and the methylation profile of the rDNA in aged vs young mice, supported by large effect sizes and permutation testing, with significant reductions in methylation of the 18S coding unit in aged, compared to young controls (p = 0.024). We found a strong positive correlation between rDNA copy number and 18S methylation across both young and aged mice (p = 0.004; Spearman rho = 0.842). After analysing publicly available muscle (skeletal and cardiac) data sets following acute insult (endurance exercise, cancer cachexia, spinal cord injury), we do not observe a similarly coordinated epi-genetic modification in rDNA biology but uncover tissue and sex-specific differences in rDNA copy number or methylation status, in isolation. These findings suggest ageing as a unique physiological insult in which coordinated epi-genomic remodelling of the rDNA region appears, representing a previously underappreciated feature of the muscle ageing trajectory.

Cellular senescence has emerged as a key contributor to age-related skeletal deterioration; however, the defining characteristics of senescent osteoblasts remain incompletely understood, hindering efforts to identify the cellular mechanisms that drive age-associated bone loss and potential therapeutic targets. Here, we compared doxorubicin- and hydrogen peroxide-induced senescence and established a robust in vitro osteoblast model that enables the stable maintenance of stress-induced premature senescence. Doxorubicin-treated MC3T3-E1 cells exhibited persistent growth arrest, a pronounced senescence-associated secretory phenotype (SASP), and impaired osteogenic function accompanied by marked mitochondrial dysfunction, including reduced respiratory capacity and altered mitochondrial morphology. Transcriptomic comparison with aged murine bone revealed a partial overlap with in vivo aging-associated gene expression signatures, particularly among genes involved in extracellular matrix organization and skeletal development, supporting the physiological relevance of the model. Importantly, key features of senescence, including the senescence-associated mitochondrial phenotype and impaired osteogenic capacity, were recapitulated in primary human osteoblasts. Collectively, these findings establish a robust model of stress-induced osteoblast senescence and demonstrate that senescent osteoblasts exhibit mitochondrial dysfunction, impaired osteogenic capacity, and molecular features that resemble aspects of skeletal aging.

IntroductionPeripheral nerve ageing leads to profound proteomic remodelling, with shifts in metabolic and inflammatory signalling pathways resembling changes that occur during nerve degeneration and regeneration following injury. Moreover, aged nerves exhibit impaired degeneration and regeneration, contributing to age-related peripheral neuropathies that show sex-specific differences in prevalence. However, it remains unclear whether these alterations arise from intrinsic nerve changes or an altered systemic environment. Therefore, we investigated the impact of sex on age-related proteome changes and nerve-intrinsic proteomic responses in young and aged male and female nerves using an ex vivo degeneration model. MethodsMass spectrometry-based proteomics were performed on young and old nerves from male and female animals, as well as on contralateral nerves after seven days of ex vivo nerve degeneration. A comparative bioinformatic analysis was then used to identify changes during ageing and ex vivo nerve degeneration that were independent of sex, as well as changes that were sex-specific. ResultsEx vivo nerve degeneration induced extensive proteome remodelling in mouse sciatic nerves that was largely independent of age and sex. Principal component and clustering analyses clearly separated intact from degenerated nerves, while revealing only subtle age- and sex-related effects, with more pronounced ageing-associated changes in males. Approximately 20% of age-regulated proteins and 7-10% of degeneration-regulated proteins exhibited sex-specific expression patterns. Degeneration was characterised by increased abundance of lysosomal and repair-associated proteins alongside reduced myelin and axonal proteins, consistent with active tissue remodelling. In aged nerves, impaired protein clearance and partial pre-activation of degeneration-associated pathways suggested altered injury responses. Comparative analyses demonstrated positive correlations of protein abundance changes between ex vivo and in vivo degeneration datasets, although the temporal dynamics were altered in aged nerves. Pathway enrichment analyses identified coordinated regulation of metabolic, RNA-processing and vesicular transport pathways, while ageing was associated with enhanced immune signalling and reduced lipid metabolism. Sex-specific analyses revealed stronger inflammatory signatures in males, whereas females exhibited enrichment of metabolic pathways, including folate biosynthesis. ConclusionThese findings reveal distinct sex-specific molecular features of peripheral nerve ageing, characterised by enhanced inflammatory signalling in males and metabolic adaptations that may confer resilience in females. Our datasets provide a comprehensive molecular resource of sex-dependent changes in peripheral nerve ageing and nerve-intrinsic injury responses, offering a foundation for identifying therapeutic strategies to promote healthy peripheral nerve ageing. Plain English summaryAge-related peripheral neuropathies are common disorders that can cause pain, numbness, weakness and reduced mobility, affecting millions of people worldwide. They become more common from around the age of 50 and affect men and women differently. These conditions are thought to result from age-related changes in the structure and function of peripheral nerves, which reduce their ability to repair themselves after injury. In this study, we used advanced protein analysis (proteomics) to investigate how ageing affects peripheral nerves in male and female mice. We also used an ex vivo model, in which nerves are studied outside the body, to examine how age and sex influence the molecular changes that occur during nerve degeneration. We found that degeneration caused widespread changes in the proteins present in the sciatic nerve in both young and old mice. Most of these changes were similar in males and females, but some important differences emerged. Male nerves showed stronger signs of inflammation, whereas female nerves showed increased activity of metabolic pathways, including those involved in folate metabolism. Ageing nerves also appeared less able to remove damaged material and showed signs of activating degeneration-related processes even before injury. Overall, the ex vivo model reproduced many of the molecular changes seen after nerve injury in living animals, although it did not fully capture the inflammatory response, suggesting that signals from the rest of the body, including factors carried in the blood, also contribute to nerve degeneration. HighlightsO_LIEx vivo nerve degeneration caused major protein changes in young and old mouse sciatic nerves. C_LIO_LIMost degeneration-related protein changes were shared between males and females. C_LIO_LIAgeing altered the nerve proteome, with stronger ageing-related shifts in males. C_LIO_LIMale nerves showed stronger inflammatory and immune-related signatures. C_LIO_LIFemale nerves showed enrichment of metabolic pathways, including folate biosynthesis, and ex vivo degeneration did not fully reproduce the inflammatory response seen after injury in vivo. C_LI

Age-related decline in skeletal muscle function, often manifesting as slower gait speed, contributes significantly to frailty and loss of independence. To uncover the molecular basis of this decline, we investigated coordinated changes across the transcriptome, miRNome, and methylome in vastus lateralis muscle from female vervet monkeys (Chlorocebus aethiops sabaeus), contrasting middle-aged animals with normal gait speed versus older animals with declining gait speed. Through multi-omics integration, we identified a molecular signature that sharply distinguishes these two groups. This signature involves key regulatory molecules, including miR-181a-5p, miR-320b and miR-425 control of SYNCRIP, miR-193b-3p regulation of MCL1 and PLAU, as well as a multi-omic regulatory network governing ZNF274 and ANP32E gene expression, and altered levels of mRNAs such as VEZT. Functional annotation implicates miRNA signatures with inverse expression of their mRNA targets operating within systems of skeletal muscle biology, metabolism, and potential immune-inflammation mechanisms. Collectively, these findings reveal an interconnected network of epigenetic, post-transcriptional, and transcriptional alterations associated with impaired muscle function during aging. This molecular signature provides novel insights into potential mechanisms driving sarcopenia and highlights specific molecules as potential targets for interventions aimed at preserving muscle health.

Osteocytes are long-lived cells that play a central role in bone homeostasis, yet age-related changes in their functional states remain poorly understood, particularly because skeletal aging involves multiple processes beyond cellular senescence. We generated an osteocyte-specific MepeCre mouse line and combined osteocyte ablation in young and middle-aged mice with skeletal phenotyping, single-cell transcriptomics, and senolytic treatment. MepeCre-driven recombination was largely confined to osteocytes, with minimal off-target activity. Osteocyte ablation increased bone mass at both ages, indicating that osteocytes constrain bone accrual as part of their role in skeletal homeostasis. However, the accompanying remodeling changes differed with age: enhanced osteoblast activity predominated in young mice, whereas reduced osteoclast-mediated bone resorption predominated in middle-aged mice. Single-cell transcriptomics revealed distinct osteocyte subpopulations whose relative abundance shifted with age, from a predominantly matrix-enriched state in young mice to an expanded aging-transitional state in middle-aged mice. Although this state showed partial enrichment of senescence-associated transcriptional signatures, senolytic treatment failed to recapitulate the increase in bone mass induced by osteocyte ablation. Osteocyte therefore regulate bone mass through age-dependent mechanisms that coincide with shifts in osteocyte-state composition. These changes emerge by middle age and may contribute to early remodeling imbalance before overt cellular senescence during skeletal aging. Graphical AbstractGraphical summary of the findings of this study. AA, amino acids; NA, nucleic acid; UA, uric acid; TCA, tricarboxylic acid.

The female reproductive system is one of the first major organ systems to show signs of age-related decline, and menopause is associated with increased risk of several diseases, including osteoporosis and cardiovascular disease. Menstrual fluid contains a mixture of blood and endometrial tissue and is a noninvasive biological sample type that has immense potential for diagnostics related to female reproductive aging. However, existing epigenetic aging clocks show limited performance in hormone-dependent tissues such as the endometrium. At Xella Health, we collected menstrual fluid (MF) samples, from a diverse patient cohort (n=66) and quantified genome-wide 5mC methylation levels. We then developed a novel, deep learning-based epigenetic aging clock that is optimized for performance in menstrual fluid and endometrial tissue. Our model, the Xella Clock, outperforms other widely used epigenetic aging clocks at predicting chronological age from MF data and on endometrial tissue. The model is a useful tool for advancing the study of female reproductive aging and can be used to examine associations between endometrial age acceleration and clinical factors.

Muscle ageing is characterized by evolutionarily conserved subcellular alterations across diverse organisms. In Caenorhabditis elegans, the decline in sarcomeric gene expression is among the earliest detectable ageing-associated changes, emerging at the onset of adulthood. To identify causal regulators of muscle ageing in an unbiased manner, we developed a genetic screening strategy that enables visual monitoring of muscle ageing at both cellular and organismal scales. Using this approach, we identified a mutation that delays the age-associated loss of sarcomeric transcripts. Unexpectedly, the mutation maps to the troponin I gene unc-27, which encodes a conserved regulator of muscle contraction not previously implicated in gene regulation. The mutation alters a single amino acid within a predicted nuclear localization signal (NLS). We found that multiple NLS motifs mediate the active transport of UNC-27 into muscle nuclei from early adulthood onward. Disruption of UNC-27 nuclear localization preserves sarcomeric gene expression during ageing and delays early hallmarks of muscle decline, including proteostatic imbalance and mitochondrial fragmentation. Transcriptomic analyses further revealed that nuclear UNC-27 selectively regulates the expression of genes encoding structural components of the muscle apparatus in adult animals. These results support the existence of a homeostatic sarcomere surveillance pathway, in which a structural protein unexpectedly acquires a transcriptional regulatory role in response to age-associated physiological state. The conservation of NLS motifs in mammalian UNC-27 orthologues suggests that this mechanism may be evolutionarily conserved, with potential relevance to human muscle physiology and disease.

Aging of skeletal muscle is traditionally defined by progressive loss of mass and strength; however, the early events that precede these outcomes remain poorly characterized. Here, longitudinal analyses revealed that impaired glucose tolerance arises at 12 months of age in Wistar rats, before detectable changes in body composition, circulating damage markers, or muscle mass. Structural loss was preceded by functional decline and structural disorganization between 15 and 18 months. Animals exhibited marked reductions in strength, mobility, and motor coordination, accompanied by extensive remodeling of muscle architecture, including a shift toward glycolytic fiber composition, extracellular matrix expansion, reduced capillarization, and increased structural heterogeneity. Early supplementation with n-3 polyunsaturated fatty acids, initiated at midlife, significantly improved glucose tolerance, reduced adiposity, and enhanced neuromuscular performance without increasing muscle mass. These functional benefits were paralleled by reduced markers of muscle damage and attenuation of histopathological alterations, indicating preservation of tissue organization rather than hypertrophic effects. Notably, a substantial fraction of these benefits persisted after cessation of supplementation, with animals displaying sustained metabolic and structural advantages at 18 months compared to age-matched controls. Collectively, these findings support a model in which skeletal muscle aging is driven by early loss of functional and structural efficiency rather than mass decline, and demonstrate that transient nutritional intervention can durably reprogram the trajectory of muscle aging. These results highlight a critical window of intervention and position n-3 supplementation as a strategy to induce persistent resilience against age-related functional deterioration. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=126 SRC="FIGDIR/small/742308v1_ufig1.gif" ALT="Figure 1"> View larger version (41K): org.highwire.dtl.DTLVardef@1f7ad39org.highwire.dtl.DTLVardef@18d8058org.highwire.dtl.DTLVardef@e552d4org.highwire.dtl.DTLVardef@1a0ee31_HPS_FORMAT_FIGEXP M_FIG C_FIG

Neurodegenerative diseases, including Alzheimer's disease (AD), are strongly associated with aging. However, the molecular mechanisms underlying pathological brain aging remain incompletely understood. In this study, we used a mouse model of telomere attrition, a major driver of cellular senescence, to perform an unbiased analysis of how telomere-driven senescence affects cellular physiology and contributes to processes relevant to neurodegenerative conditions. After validating the presence of senescence hallmarks in telomerase-deficient brains, we characterized their transcriptomic and proteomic profiles. Mitochondrial function and associated energy metabolism emerged as the major dysregulated pathways, driven predominantly by proteomic rather than transcriptomic changes. Functional biochemical analyses on isolated brain mitochondria demonstrated impaired electron transport chain (ETC) complex activity and reduced energetic status, despite preserved ETC complex integrity and mitochondrial content. Further analyses in senescent primary neurons indicated an accumulation of dysfunctional mitochondria, characterized by increased reactive oxygen species (ROS) production and reduced ATP levels, although basal cellular respiration was maintained. At the tissue level, these alterations were associated with moderate reductions in neuronal density in the subiculum and cortical layer V, indicating region-specific vulnerability rather than widespread neurodegeneration. We propose that a major consequence of telomere dysfunction associated with pathological brain aging is the downregulation of mitochondrial activity, which contributes to the selective vulnerability of specific brain regions. These findings highlight mitochondrial pathways as attractive targets for interventions aimed at preserving brain health during aging.

Aging is associated with proteome remodelling and progressive accumulation of insoluble proteins. Identifying age-enriched proteins that undergo aggregation and evaluating compounds capable of modulating their behaviour may provide insights into interventions that promote healthy aging. Here, we report a proteome-guided strategy to identify age-associated aggregation-prone proteins and evaluate phytochemicals targeting conserved proteins in Caenorhabditis elegans. We identified proteins whose abundance increased more than four-fold in aged worms compared with young worms, many of which also accumulated in the age-associated insoluble proteome, and subsequently identified their human orthologs for comparative analysis. Based on biological relevance, structural conservation, and availability of high-confidence structural models, glutamine-fructose-6-phosphate aminotransferase-2 (GFAT-2) was selected for molecular docking. Screening of fifteen phytochemicals against C. elegans GFAT-2 and its human ortholog GFPT1 identified quercetin as the strongest predicted binder, exhibiting conserved interactions with both proteins. However, treatment of worms with quercetin did not significantly alter global protein insolubility during aging. This may reflect its ability to modulate inappropriate protein-protein interactions without substantially affecting the overall aggregation burden. These findings underscore the need for experimental validation of favourable in silico docking predictions. More broadly, this study provides a proteome-guided framework for prioritizing age-associated aggregation-prone proteins as candidate therapeutic targets for preserving proteostasis during aging.

The liver is organized into tightly regulated zones with distinct metabolic functions but zonation erodes with age. Cellular senescence contributes to aging and liver diseases, however, its impact on aging biology is ill-defined. As part of The Cellular Senescence Network Consortium, we used multiple spatial transcriptomics approaches (GeoMx, Visium, CosMx) with snRNA-seq to profile senescence signatures, zonation markers, and metabolic pathways in livers from wild-type (WT) mice of multiple ages. We observed a loss of canonical zone signatures in aged mouse livers characterized by "expansion" of midlobular (zone 2) marker gene expression, accompanied by diminished expression of zone 3 marker genes by middle-age (18 months), indicative of loss of cell identity. Multiple analytic approaches identified distinct age-, zone- and sex-specific senescence signatures, which were significantly associated with zonation markers changes. This was recapitulated in Ercc1 mutant models of accelerated senescence, supporting a causal role of senescent cells in liver aging. A "no-zone" hepatocyte-like cluster expanded with age and with the strongest Senescence-Associated Secretory Phenotype (SASP) profile. Gene expression profiles from senescent hepatocytes implicate decreased WNT signaling and increased BMP as contributing to age-related loss of zonation. Together, these data elucidate the role of senescent cells in driving aging biology in non-diseased liver through disruption of cell:cell signaling and the loss of metabolic and cell identity gene expression necessary for hepatocyte function.

Muscle function depends on the ability of myofibrils to withstand and repair mechanical damage, yet how adult muscles remodel damaged myofibrils remains poorly understood. Here, we establish a Drosophila model that allows the induction and longitudinal visualization of extensive myofibril damage and recovery in intact adult femur muscles. Sustained muscle depolarization caused extensive disruption of myofibrillar organization, with severe damage characterized by near-complete loss of Z-disc structures. Remarkably, myofibril architecture and muscle function were largely restored within days, revealing a substantial capacity for myofibril reconstruction in adult femur muscles. We identified two distinct states of myofibril damage, mild and severe, with mild damage appearing before severe damage during aging, suggesting a progressive process of myofibril deterioration and repair failure. We further show that filamins mechanosignaling is required for efficient myofibril remodeling. Following damage, wild-type filamin redistributes from the Z-disc and accumulates outside the myofibrils, whereas constitutively open filamin remains Z-disc-associated and constitutively closed filamin redistributes but results in increased damage and impaired recovery. These findings suggest that effective repair requires dynamic transitions between filamin conformational states and that filamin redistribution is an active component of the damage response rather than simply a consequence of muscle injury. During aging, filamin progressively redistributes from the Z-disc and muscle damage accumulates, with severe damage increasing after the appearance of mild damage. Together, our findings reveal a previously unappreciated capacity of adult muscle to reassemble damaged myofibrils and identify filamin mechanosignaling as a key component of this repair process, providing a framework for understanding how defective mechanosensing may contribute to age-related muscle decline and muscle disease.

Aging progressively challenges neuronal proteostasis, redox homeostasis, and metabolism, yet the molecular changes that precede functional decline remain poorly understood. Endoplasmic reticulum oxidoreductin 1 (ERO1), a key regulator of oxidative protein folding, links endoplasmic reticulum (ER) proteostasis with cellular redox balance and is elevated in aging and neurodegenerative contexts. Here, we investigated how neuronal ERO1L elevation reshapes cellular homeostasis before overt dysfunction in Drosophila melanogaster. Endogenous ERO1L expression increased with age, and neuronal ERO1L elevation shortened lifespan and caused progressive locomotor decline. This effect was strongly cell-type dependent, as ERO1L elevation in glia, muscle, or fat body did not produce a comparable survival phenotype. At day 5 post-eclosion, locomotor performance remained preserved and major brain reactive-oxygen-species (ROS) accumulation was not yet detectable, defining a pre-symptomatic stage. Multi-omic profiling at this stage revealed selective remodelling of ER proteostasis, redox defence, and mitochondrial-energy pathways, together with changes in central-carbon, nitrogen, and purine metabolism. In contrast to these broadly adaptive responses, chromatin- and RNA-homeostasis-associated proteins were selectively reduced, accompanied by decreased HP1, dFmr1, and Piwi expression and increased transposable-element transcripts. Thus, neuronal ERO1L elevation establishes a pre-symptomatic state in which proteostatic and metabolic adaptation coexists with early vulnerability of nuclear and RNA-homeostasis pathways, preceding overt oxidative stress and behavioural decline. These findings provide an in vivo framework to investigate how age-associated ERO1L elevation may progressively reduce neuronal resilience during brain aging.