Longevity Papers

The global demographic shift towards an aging population has amplified the public health challenge posed by immunosenescence, a progressive remodeling of the immune system that compromises host defenses. This age-related decline is characterized by a reduction in adaptive immunity, marked by a diminished pool of naïve T-cells and an increased susceptibility to infections and poor vaccine responses. Simultaneously, it is defined by a paradoxical state of chronic low-grade inflammation, or "inflammaging," which accelerates age-related pathologies. This review posits "immunopause" as a conceptual framework for a state of severe immune decline, a state often viewed as an inevitable consequence of aging. However, the evidence synthesized herein challenges this view by positioning physical exercise as a potent, non-pharmacological intervention capable of countering this process. The report systematically reviews the cellular, molecular, and systemic mechanisms through which exercise exerts its beneficial effects, including the rejuvenation of T-cell repertoires, the regulation of cytokine networks, and the modulation of multi-organ axes involving myokines and the gut microbiome. By improving the efficacy of existing immune cells and shifting the systemic inflammatory milieu, chronic physical activity promotes a more "youthful" and functional immune phenotype. This synthesis not only underscores exercise's potential to enhance vaccine efficacy and serve as an adjuvant therapy for age-related diseases but also argues for a paradigm shift: from viewing immune aging as an immutable process to recognizing it as a modifiable state. The report concludes that exercise provides a scientifically validated strategy to extend healthspan and prevent the pathological state of immunopause.

C-reactive protein (CRP) and growth differentiation factor 15 (GDF15) are important markers of inflammation associated with brain health. Compared to plasma, DNA methylation (DNAm) measures of CRP and GDF15 may provide stable epigenetic measures of chronic exposure to inflammation and could therefore be robustly predictive of inflammation-related brain aging and neurodegeneration. We leveraged a subsample of Baltimore Longitudinal Study of Aging (BLSA) participants with DNAm/plasma data and longitudinal neuroimaging/cognition data (n = 430-1100). We used a proteome-wide analysis to characterize the biology of DNAm CRP and GDF15, and latent growth curve models to explore the associations with longitudinal trajectories of 19 brain region volumes and five cognitive domains. Finally, we related DNAm/plasma CRP and GDF15 to dementia risk in two external cohorts. DNAm CRP and GDF15 showed a proteomic signature consistent with systemic immune activation. We identified several brain regions with significant associations between elevated DNAm CRP And GDF15 and (a) lower brain volume level (at age 75) and (b) greater rate of atrophy. Compared to plasma CRP, DNAm CRP was more strongly associated with brain volume, cognitive trajectories, and dementia risk. DNAm and plasma GDF15 were similarly associated with several total lobar, total lobar white matter, and AD-relevant region trajectories and dementia risk, but DNAm measures outperformed plasma measures in relation to cognitive trajectories. Epigenetic signatures of CRP and GDF15 reflect immune and inflammation-related pathway activation. These signatures, especially DNAm CRP, were associated with accelerated brain atrophy, cognitive decline, as well as long-term dementia risk.

Aging impairs tissue function and regenerative capacity across multiple organs. This study demonstrates that extracellular vesicles derived from human nasal mucosa (nmEVs) exert systemic antiaging effects in aged mice. Treatment with nmEVs improves cognitive performance and alters hippocampal aging signatures related to synaptic signaling and the regulation of neuroplasticity. In parallel, transcriptomic analysis of five major aging-sensitive organs reveals that nmEVs broadly ameliorate age-associated transcriptional changes, notably by restoring circadian rhythmicity and suppressing cellular senescence-related pathways. At the cellular level, nmEVs alleviate senescence phenotypes in aged human bone marrow mesenchymal stem cells, restore proliferation and osteogenic capacity, and reactivate core clock gene expression. These effects are accompanied by modulation of the p53 pathway, suggesting its involvement in nmEV-mediated rejuvenation. Importantly, lacking the need for cell isolation and ex vivo expansion, nmEVs offer a practical, age-independent source of extracellular vesicles with high clinical accessibility. Together, these findings support the translational potential of nmEVs as a multifaceted therapeutic candidate for systemic aging intervention.

The corpus callosum (CC), the brain's largest white matter commissure, undergoes significant age-related atrophy that varies across subregions. However, how network-specific callosal connections age and relate to cognitive performance remains poorly understood. We analyzed diffusion-weighted imaging data from 718 healthy adults (ages 36-100 years) from the Human Connectome Project-Aging dataset. Using a tract-to-region approach, we quantified CC tract density within seven canonical functional networks. Cubic polynomial models examined network-specific aging trajectories, while correlation and moderation analyses investigated relationships with cognitive and motor performance across age groups. Network-specific CC tract densities showed distinct aging patterns. Somatomotor and Default Mode networks exhibited highest baseline tract density but steepest age-related declines (β = -0.068 and -0.025, respectively, p < 0.001), while Visual and Limbic networks showed relative preservation. CC tract density showed small-to-medium associations with executive function, memory, and motor performance (r = -0.32 to 0.33). Critically, age moderated these brain-behavior relationships: associations were minimal in younger adults but became progressively stronger in older adults across cognitive domains. The CC follows network-specific aging trajectories, with high-order association networks showing accelerated decline while primary sensory networks remain preserved. Strengthening brain-behavior associations with advancing age suggest callosal integrity becomes increasingly critical for maintaining cognitive performance in later life.

Human dental pulp stem cells (hDPSCs) senescence impairs their proliferation and osteogenic differentiation, critical for dental stem cell therapy. This study evaluated the effects of Resveratrol on the senescence of hDPSCs to explore new therapeutic strategies. Metabolomic analysis identified age-related metabolic differences in dental pulp tissues, with enriched pathways linked to Resveratrol. In vitro, Resveratrol improved proliferation, delayed senescence, promoted osteogenic differentiation, and enhanced mitochondrial autophagy, function, and biogenesis in senescent hDPSCs, reducing mitochondrial damage and oxidative stress. Mechanistically, silencing PINK1 or PGC-1α reversed Resveratrol-mediated promotion of proliferation, osteogenesis, and senescence suppression. Blocking SIRT1 abrogated its effects on mitochondrial quality control. These findings highlight Resveratrol's potential to mitigate hDPSCs senescence via SIRT1-dependent mitochondrial regulation, offering insights for age-related dental regenerative therapies.

Loss of Fibronectin (FN) from the skeletal muscle stem cell (MuSC) niche represents a root cause of regenerative failure in aging. While FN has pleiotropic functions during healthy skeletal muscle regeneration, it remains unclear how aging affects its spatiotemporal specificity for MuSCs. Here, we demonstrate that activated MuSCs secrete an autoregulatory FN splice variant containing the EDB extra domain (EDB(+) FN), which is not expressed by accessory cells in the niche. EDB(+) FN splicing in MuSCs depends on serine/arginine-rich splicing factor 1 (Srsf1) whose promoter is controlled by Smad3. EDB(+) FN knockdown or downregulation in aging affects MuSC proliferation through aberrant integrin signaling and impairs skeletal muscle regeneration. During a defined regeneration interval in aged mice, Smad3 activation using transforming growth factor-beta 1 (TGFβ1) improves MuSC function and skeletal muscle repair by stimulating EDB(+) FN secretion. Altogether, we identify and characterize the TGFβ1-Smad3-Srsf1-EDB(+) FN pathway as a therapeutic target for age-associated regenerative failure.

In many countries, lifespan has been increasing faster than healthspan, leading to more years spent with late-life disease and highlighting the need for reliable biomarkers to measure biological aging and to plan personalized interventions to extend healthspan. We used data from the Berlin Aging Study II (BASE-II, 60-80 years of age at baseline, average follow-up 7.4 +/- 1.5 years, range 3.9-10.4, n=1,083) to compare 14 biomarkers of aging recently consented by an expert panel for the use as outcome measures in intervention studies: Insulin-like growth factor 1 (IGF-1), growth-differentiating factor-15 (DNA methylation derived, DNAmGDF15), high sensitivity C-reactive protein (CRP), interleukin-6 (IL 6), muscle mass, muscle strength, hand grip strength (HGS), Timed-Up-and-Go (TUG), gait speed, standing balance test, frailty index (FI), cognitive health, blood pressure, and epigenetic age (DunedinPACE). Cox proportional hazard regression analyses were performed to investigate the predictive role for all-cause mortality and to identify subgroups of the three most frequent causes of death observed in BASE-II. Results were adjusted for age, sex, lifestyle factors, and genetic ancestry. In adjusted models of all-cause mortality, HGS, IL 6, standing balance, cognitive health, and epigenetic age (DunedinPACE) significantly predicted mortality, with the epigenetic age (DunedinPACE) emerging as the strongest predictor. In contrast, CRP, Gait Speed, IGF-1, blood pressure, muscle mass, DNAmGDF15, FI and TUG were not associated with mortality. These results were corroborated in subgroup analyses stratified by cause of death. Feature selection identified a minimal biomarker set comprising muscle mass, standing balance, and epigenetic age (DunedinPACE) that predicted mortality with nearly the same discriminative accuracy (C-index = 0.63) as the full model including all biomarkers (C-index = 0.65).

Collagen supplementation has gained attention with increasing claims regarding its beneficial effects on healthy aging based on clinical observations and lifespan extension in pre-clinical models; however, how and which part of an ingested collagen promotes healthy longevity is unknown. Here, we identified the minimal required unit of ingested collagen, which consists of the proper ratio of three glycine to one proline to one hydroxyproline that was sufficient to increase the motility-healthspan and lifespan of C. elegans, as well as collagen homeostasis in human fibroblasts in vitro. Supplementation in 20-month-old mice improved grip strength and prevented age-related fat accumulation. In a clinical observational trial (ISRCTN93189645, 03.07.2025), oral supplementation in humans demonstrated improved skin features within three months and a reduction in biological age by 1.4 years (p = 0.04) within 6 months. Thus, a ratio of three amino acids elicits evolutionarily conserved health benefits from ingested collagens.

Objectives: Neurons coexpressing Agouti-related peptide (AgRP) and Neuropeptide Y (NPY) are an essential component of an interoceptive circuit regulating hunger and metabolism. Their activity is closely linked to metabolic state and their output is sensitive to diet-induced plasticity, which may influence the development of obesity and associated metabolic diseases. However, most studies use young male mice, even though obesity and its comorbidities are sensitive to both biological sex and aging, leaving a significant gap in our understanding of the role of these neurons in females and in older animals. Our goal was to begin to address this gap by investigating the effects of diet and age on AgRP/NPY neuronal activity in female mice in both early adulthood and midlife. Methods: Female transgenic NPY-GFP mice aged 8-32 weeks were fed either a standard control chow diet or a high-fat, high-sugar diet (HFD) for 8-24 weeks and brain slice patch clamp electrophysiology was used to measure the response of AgRP/NPY neurons. Results: We found that in young, lean female mice, the baseline firing rate of AgRP/NPY neurons is significantly elevated compared to age-matched males, thus the impact of HFD on the output of these neurons is blunted relative to control. However, in the baseline firing rate of neurons from lean middle-aged female mice is significantly lower, resulting in a greater relative impact of HFD on AgRP/NPY neuronal output, the development of neuronal leptin resistance, and significant weight gain. Conclusions: Both sex and age significantly impact the function and modulation of AgRP/NPY neurons, emphasizing the need to include these biological variables in experimental design.

The properties of functional brain networks are an important determinant of cognitive function in aging and dementia. Despite this, few studies have comprehensively examined demographic and biopsychosocial predictors of functional brain networks, and none have attempted to do so across the adult lifespan while accounting for collinearity among these predictors. The current study used data from 525 individuals between the ages of 35 and 100 years from the Human Connectome Project 2.0 Lifespan Release, which includes task-based functional neuroimaging, physical and emotional health, and demographic information. Two functional brain network properties previously identified as moderators of cognitive decline, entropy and modularity, were used as outcome metrics in four elastic net regression models that identified and ranked predictors of these metrics as well as their age-interaction terms. We identified biological sex, sleep duration, instrumental support, visual acuity, education, social isolation, diastolic blood pressure, and vigorous physical activity as the strongest and most consistent predictors of entropy and modularity beyond age. Importantly, these predictors differed from ranked correlational results, suggesting many predictors share large amounts of overlapping statistical variance. Additionally, we found that biological sex exhibited a significant moderation effect such that males demonstrated greater age-related decreases to network resilience with increasing age compared to females. In the current study, we ranked biopsychosocial health determinants of network properties in an adult lifespan sample. Given previous research implicating modularity and entropy as possible measures of cognitive reserve, these results may inform our understanding of resilience to cognitive decline in aging.

Obstructive sleep apnea (OSA) accelerates cardiovascular aging through intermittent hypoxia (IH). We exposed mice to 22 months of IH, modeling lifelong OSA. Compared to controls, IH mice exhibited higher mortality, elevated blood pressure, impaired systolic and diastolic function, vascular stiffening, reduced coronary reserve, and ECG abnormalities. These findings suggest that chronic IH significantly exacerbates cardiovascular decline with aging, underscoring the importance of early OSA diagnosis and intervention.

Age related changes in circulating exosomes are implicated in cerebrovascular aging and the pathogenesis of Alzheimers disease (AD). Neurovascular dysfunction and blood brain barrier (BBB) breakdown are recognized as early events in AD, often preceding amyloid{beta} deposition. Primary human brain micro endothelial cells (HBMECs) from a 38 year-old male were treated with exosomes from young (18 to 25 years) and old (65 to 72 years) donors. Whole transcriptomic RNA sequencing analysis identified 5,432 differentially expressed genes, which were organized into five transcriptional clusters. Two principal clusters demonstrated reciprocal patterns: 1) exosomes derived from serum of older adult donors (65 to 72 years) downregulated genes essential for mitochondrial function (e.g., oxidative phosphorylation) and protein synthesis (e.g., ribosomal biogenesis) and 2) upregulating genes linked to inflammation, junctional remodeling, and proliferative signaling. Crucially, subsequent treatment with exosomes derived from serum of young adult donors (18 to 25 years) reversed these detrimental transcriptomic profiles via restoration of the expression of mitochondrial and ribosomal machinery toward baseline and suppressed the inflammatory and maladaptive proliferative signaling induced by exosomes derived from serum of older adult donors. These findings demonstrate that exosomes derived from serum of young adult donors can counteract detrimental signals of aging at the transcriptional level, reinforcing the cellular architecture underlying BBB integrity. This supports the therapeutic potential of using exosomes derived from serum of young adult donors to reverse endothelial aging and interrupt the early neurovascular dysfunction that contributes to the progression of AD.

Spinal degenerative diseases in elderly patients often require spinal fusion, but outcomes are limited by an aging microenvironment and stem cell dysfunction or depletion. In this study, we developed a bone morphogenetic protein-2 (BMP-2)/sulfated chitosan (SCS)/calcium phosphate cement (CPC) composite scaffold to enhance spinal fusion in aged mice. BMP-2/SCS significantly improved spinal fusion success rates (83.3 %) compared to BMP-2 alone (16.7 %) and high-dose BMP-2 (50 %). The BMP-2/SCS group promoted robust new bone formation and H-type vessel development, facilitating vascular-bone coupling in the fusion region. Mechanistically, SCS suppressed BMP-2-induced osteoclast overactivation and reduced MMP-9 secretion, leading to vertebral skeletal stem cell (vSSC) rejuvenation. Rejuvenated vSSCs primarily differentiated into the osteogenic bone/cartilage lineage while stromal lineage differentiation was suppressed. In contrast, co-administration of BMP-2 and alendronate sodium abolished BMP-2-mediated increases in vSSC numbers, vSSC rejuvenation, and bone integration, highlighting the indispensable role of osteoclast activity in BMP-2-induced bone regeneration. Collectively, this study demonstrates that BMP-2/SCS scaffolds effectively reverse age-related deficiencies by creating a rejuvenated bone microenvironment, promoting vascular-bone coupling, and enhancing osteogenesis, offering a promising strategy to improve spinal fusion outcomes in elderly patients.

Vitamin C has been long recognized as an important nutrient for skeletal biology, historically attributed to its role in collagen synthesis and connective tissue integrity. Recent studies, however, reveal vitamin C as a critical epigenetic regulator of cellular differentiation. As a required cofactor for α-ketoglutarate-dependent dioxygenases, vitamin C controls the enzymatic activity of a broad array of histone and DNA demethylases, thereby modulating chromatin accessibility and driving cell-specific gene expression. This review provides a novel, integrated perspective that directly links vitamin C's epigenetic functions to osteogenesis and skeletal health, highlighting experimental evidence that redefines its role beyond collagen maturation and antioxidant defense, and elucidating its sex-dimorphic effects. Importantly, inadequate vitamin C status remains widespread across diverse socioeconomic groups even in Western countries, with low vitamin C intake associated to higher risk of osteoporosis and fractures in the elderly. Viewed through the dual lenses of epigenetic-mechanistic function and clinical relevance, vitamin C emerges as a central epigenetic determinant of skeletal health and a safe, low-cost, and scalable adjuvant to complement current bone therapies. Integrating nutrient epidemiology, clinical data and epigenetic-mechanistic insights may enable targeted interventions to enhance skeletal resilience, particularly in vulnerable populations.

Decades of publicly available molecular studies have generated millions of samples testing diverse interventions, yet these datasets were rarely analyzed for their effects on aging. Aging clocks now enable biological age estimation and life outcome prediction from molecular data, creating an opportunity to systematically mine this untapped resource. We developed ClockBase Agent (www.clockbase.org), a publicly accessible platform that reanalyzes millions of human and mouse methylation and RNA-seq samples by integrating them with over 40 aging clock predictions. ClockBase Agent employs specialized AI agents that autonomously generate aging-focused hypotheses, evaluate intervention effects on biological age, conduct literature reviews, and produce scientific reports across all datasets. Reanalyzing 43,602 intervention-control comparisons through multiple aging biomarkers revealed thousands of age-modifying effects missed by original investigators, including over 500 interventions that significantly reduce biological age (e.g., ouabain, KMO inhibitor, fenofibrate, and NF1 knockout). Large-scale systematic analysis reveals fundamental patterns: significantly more interventions accelerate rather than decelerate aging, disease states predominantly accelerate biological age, and loss-of-function genetic approaches systematically outperform gain-of-function strategies in decelerating aging. As validation, we show that identified interventions converge on canonical longevity pathways and with strong concordance to independent lifespan databases. We further experimentally validated ouabain, a top-scoring AI-identified candidate, demonstrating reduced frailty progression, decreased neuroinflammation, and improved cardiac function in aged mice. ClockBase Agent establishes a paradigm where specialized AI agents systematically reanalyze all prior research to identify age-modifying interventions autonomously, transforming how we extract biological insights from existing data to advance human healthspan and longevity.

Aging may be conceptualized as a wound that fails to heal, characterized by persistent, unresolved inflammation. Building on Ogrodnik's "unhealed wound" model, this Perspective extends the Exposure-Related Malnutrition (ERM) framework to propose a bioenergetic interpretation of aging. ERM links chronic stress adaptation, nutrient misallocation, and mitochondrial insufficiency to sustained bioenergetic debt that impedes the transition from catabolic containment to anabolic repair. Across tissues, this energetic shortfall manifests as metabolic inflexibility, lipid-droplet accumulation, and a continuum of adaptive mitochondrial dysfunction that remains reversible until the threshold of senescence-the terminal stage of unresolved adaptation. Recognizing bioenergetic availability as the principal determinant of regenerative success reframes mitochondrial dysfunction and senescence not as primary causes of aging but as downstream consequences of chronic energetic exhaustion. Within this continuum, aging reflects a progressive loss of rhythmic catabolic-anabolic cycling that supports metabolic adaptation. Transient metabolic stress normally induces hormetic activation followed by anabolic recovery, but when this oscillation fails, adaptive hormesis gives way to maladaptive exhaustion. Aging thus emerges from the erosion of bioenergetic rhythm-a transition from recovery with renewal to endurance without repair.

Aggregation of amyloidogenic proteins is linked to age-related diseases. The presence of interfaces can affect their aggregation mechanism, often speeding up aggregation. α-Synuclein (αSyn) can adsorb to biomolecular condensates, leading to heterogenous nucleation and faster aggregation. Understanding the mechanism underlying localization of amyloidogenic proteins at condensate interfaces is crucial for developing strategies to prevent or reverse their binding. We show that αSyn localization to the surface of peptide-based heterotypic condensates is an adsorption process governed by the protein's condensate-amphiphilic nature, and the condensate surface charge. Adsorption occurs reversibly in multiple layers and plateaus at micromolar concentrations. Based on these findings, we rationally design three strategies to modulate αSyn accumulation: (i) addition of biomolecules that decrease the condensate ζ-potential, such as NTPs and RNA, (ii) competitive adsorption of proteins targeting the condensate interface, such as G3BP1, DDX4-YFP, EGFP-NPM1, Hsp70, Hsc70, and (iii) preferential adsorption of αSyn to membranes. Removing αSyn from the condensate interface slows aggregation, highlighting potential cellular control over protein adsorption and implications for therapeutic strategies.

Diabetic kidney disease (DKD) progression involves intricate interactions among senescence, oxidative stress, inflammation, and fibrosis. This study systematically investigates the regulatory role and molecular mechanisms of NUAK1 in DKD pathogenesis. Bioinformatics analysis of Gene Expression Omnibus data sets identified NUAK1 as a differentially expressed gene, validated in human kidney proximal tubule epithelial (HK-2) cells, high-fat diet and streptozotocin-induced DKD mice, d-galactose-induced senescent mice, and human peripheral blood mononuclear cells. Functional studies demonstrated that NUAK1 inhibition via siRNA knockdown, pharmacological inhibitors, or kidney tubule-targeted adeno-associated virus serotype carrying shRNA against NUAK1 delivery attenuated reactive oxygen species-tumor protein 53 (ROS/P53) axis-mediated renal tubular senescence, oxidative stress, inflammation, and fibrosis in vitro and in vivo. Mechanistically, chromatin immunoprecipitation quantitative PCR revealed that transcription factor ETS1 directly binds to the NUAK1 promoter, driving its transcriptional activation in DKD. Furthermore, molecular docking and dynamics simulations identified Asiatic acid (AA) as a potent NUAK1 inhibitor, with a stable binding affinity. AA suppressed NUAK1 expression and downstream pathological processes, ameliorating renal injury in DKD models. These findings elucidate the role and regulatory mechanisms of NUAK1 in modulating ROS/P53 axis-driven tubular senescence and oxidative stress, providing a theoretical basis for structure optimization in drug development targeting NUAK1.

Testosterone insufficiency disrupts spermatogenesis and expedites male aging. Autophagy facilitates testosterone synthesis. However, a molecular reduction mechanism of autophagy-related protein 4 homolog B (ATG4B) has not been established. Herein, we reveal that peroxiredoxin 1 (PRDX1) is clinically associated with male fertility disorders. Adult mutant mice with Leydig cell (LC)-specific deletion of the Prdx1 gene exhibit premature testicular aging and infertility. A series of in vivo and in vitro experiments, in combination with multi-omics analyses, demonstrate that PRDX1 inactivation impairs lipophagy and testosterone synthesis in LCs. Mechanistically, Cys52 and Cys173 in PRDX1 specifically target the redox-site Cys78 in ATG4B to preserve the delipidating activity of Cys74 in ATG4B, thereby promoting autophagic flux. Furthermore, PRDX1 dysfunction exacerbates testicular and systematic aging in aged mice, which can be alleviated by a 2-cysteine mimic, ebselen. Collectively, our findings demonstrate that PRDX1 promotes lipophagy and testosterone synthesis by regulating ATG4B. Our findings also propose the potential application of ebselen in the prevention and treatment of aging-related disorders, including late-onset hypogonadism.

The lack of safe, durable therapeutics that act against both biological aging and Alzheimer's disease is an unmet clinical need. To bridge this gap, we devised an artificial intelligence (AI)-enabled approach that pairs rapid compound triage with mechanistic target deconvolution. Our AI-driven screening highlighted melatonin (MLT) as a promising candidate. Serum profiling of 161 human individuals confirmed an age-related fall in circulating MLT level, while subsequent in vivo and in vitro experiments showed that MLT rescues cognition, suppresses neuroinflammation, and alleviates senescence phenotypes. Proteolysis targeting chimera (PROTAC)-guided chemoproteomic deconvolution next pinpointed the histone acetyltransferase p300 as MLT's target. Integrated Cleavage Under Targets and Tagmentation, single-cell RNA sequencing, and spatial transcriptomics revealed that MLT-bound p300 cooperates with specificity protein 1 (SP1) at a brain and muscle ARNT-like protein 1 super-enhancer, elevating histone H3 lysine-27 acetylation and reengaging a circadian-epigenetic program that links redox resilience to neuroprotection. By combining AI-driven discovery with PROTAC-based target mapping and super-enhancer-centric mechanistic resolution, our study identifies MLT as a dual-action candidate and sets out a reproducible "AI-to-clinic" paradigm for multitarget drug innovation in aging-related neurodegeneration.

Commensal microbiota plays crucial roles in maintaining tissue homeostasis, yet its impact on cellular ageing and inflammaging across diverse cell types remains poorly understood. Here we present a comprehensive single-cell epigenomic and transcriptomic atlas of various tissues from mice aged under specific pathogen-free (SPF) or germ-free conditions, revealing context-dependent effects of microbiota on cellular ageing. Microbiota conferred beneficial effects in young mice but accelerated various ageing features in old, such as age-related AP-1 pathway upregulation, senescence and transcriptomic alterations, likely due to age-associated dysbiosis. Strikingly, inflammatory signatures persisted across cell types in aged germ-free mouse tissues, establishing sterile inflammation as an intrinsic feature of ageing. Age-associated B cells expanded equally under germ-free conditions and (SPF) conditions, raising the possibility that they function as intrinsic, microbiota-independent drivers of inflammageing and potential therapeutic targets. The atlas provides a resource for distinguishing intrinsic ageing features from those modulated by the microbiota, illuminating mechanisms of cellular ageing and potential anti-ageing interventions.

Healthy aging alone can lead to cognitive decline, decreased brain size, protein aggregation, accumulation of senescent cells and neuroinflammation. Furthermore, age is the primary risk factor for several neurodegenerative disorders such as Parkinson's and Alzheimer's disease. Age-related neuroinflammation, as known as inflammaging, is thought to restrict brain plasticity. Perineuronal nets (PNNs), specialized extracellular matrix structures surrounding fast-spiking parvalbumin (PV) interneurons, regulate plasticity and protect neurons from oxidative stress. Given the known impact of inflammaging on neural circuits, this study examines age-associated changes in PNN homeostasis, glial activation, and neuroinflammation in two brain regions relevant to age-related neurodegenerative diseases.

Existing proteomic aging clocks have been derived from the overall population, with little consideration of extended models tailored to individuals with different glycemic status. We aimed to quantify glycemic status-dependent proteomic signatures of aging and developed proteomic aging scores (ProAS) for health risk prediction. A total of 2923 plasma proteins were measured using Olink in 46,047 UK Biobank participants, including 37,353 with normoglycemia, 5977 with prediabetes, and 2717 with diabetes. Using a three-step screening approach, we identified 11, 23, and 21 representative protein biomarkers associated with all-cause mortality among individuals with normoglycemia, prediabetes, and diabetes, respectively. Three proteins (GDF15, EDA2R, and WFDC2) were shared across all groups, with GDF15 emerging as the top-ranked important protein in normoglycemia and prediabetes and WFDC2 in diabetes. The protein-based ProAS according to glycemic status showed significant associations with diverse health outcomes. Adding the ProAS in the models improved the predictive accuracy of mortality and incident diseases beyond conventional risk factors, but the performance progressively diminished as glycemic status deteriorated. In addition, 72, 51, and 36 out of 102 modifiable factors spanning seven categories were identified as determinants for ProRS in normoglycemia, prediabetes, and diabetes, respectively. Our findings extend the current proteomic clocks by revealing glycemic status-specific aging patterns and their ability to predict age-related outcomes, potentially refining risk stratification and targeted interventions for healthy aging.

The physical coupling between the nucleus and the cytoskeleton is essential for the mechanobiological adaptation of cells to mechanical cues presented by the surrounding extracellular matrix (ECM). Although aging is known to influence both cellular and ECM mechanical properties, it remains poorly understood how cellular senescence, a hallmark of aging, affects cellular mechano-adaptation. Here, we use substrate stiffness as a mechano-modulatory cue across three distinct models of senescence and demonstrate that senescent fibroblasts are limited in their capacity to integrate mechanical signals of increasing stiffness. The senescent nucleus undergoes progressive actin-mediated deformation and flattening as substrate stiffness increases, until a mechanical threshold is reached that provokes a decoupling of the nucleus from the cytoskeleton. This mechanical disengagement of the nucleus on stiff substrates is accompanied by a loss of cytoskeletal organization, abnormal focal adhesion (FA) maturation, and nuclear softening. We further suggest that the loss of nuclear compression is linked to changes in the nuclear localization of the key mechanosensitive transcriptional regulator Yes-associated protein (YAP). Our findings reveal a fundamental biophysical limitation in the mechano-adaptive response of senescent cells to high-stiffness environments, conditions typically associated with advanced tissue maturation and pathological scarring, which may underlie altered nuclear mechanotransduction and contribute to their specific role in both physiological and pathological contexts.

Ovarian aging is a fundamental process in female reproductive biology with broad implications for overall health and aging. As global populations age, understanding its mechanisms and systemic effects has gained urgent clinical relevance. The ovary, beyond its reproductive role, is increasingly recognized as a regulator of systemic aging due to the widespread presence of estrogen receptors. Declining ovarian function accelerates not only reproductive senescence but also contributes to age-related disorders including osteoporosis, neurodegenerative diseases, and cardiovascular conditions. However, research on ovarian aging remains fragmented, lacking integrative analysis. This review synthesizes recent advances in the cellular and molecular mechanisms underpinning ovarian aging, such as genomic instability, metabolic and oxidative stress, and microenvironmental alterations. It further discusses how ovarian decline influences systemic aging pathways and disease susceptibility and evaluates emerging therapeutic strategies such as antioxidant interventions, stem cell therapy, and ovarian tissue transplantation. By providing a comprehensive overview of ovarian aging from mechanisms to interventions, this review aims to bridge existing knowledge gaps and inspire future research toward improving women's healthspan and quality of life.

Aging constitutes the largest risk factor for melanoma progression. While a contribution of factors secreted from senescent skin fibroblasts to the progression of melanoma has been proposed, the nature of such factors and subsequent underlying mechanisms remains elusive. Here we show that the chemokine GCP-2 is excessively released by senescent fibroblasts in vitro and the skin of old melanoma patients. GCP-2 regulates, via phosphorylation of the transcription factor CREB at serine 133, defense-, cell cycle control-, and glycolysis-enhancing genes in melanoma cell lines. GCP-2 promotes oncogenic properties in vitro and in vivo in murine melanoma models. Inhibition of CREB phosphorylation in melanoma cells represses glycolytic target genes and induces a switch from glycolysis to oxidative phosphorylation that translates into a significant decline in tumor size in vivo in murine melanoma models. This study identifies a senescent fibroblast to chemokine to CREB to metabolic axis that drives melanoma progression. Targeting this axis may hold promise for novel therapeutic approaches in difficult-to-treat melanoma in older adults.

In young animals, oligodendrocyte progenitor cells (OPCs) undergo robust differentiation, progressing through stages to become pre-myelinating oligodendrocytes (Pre-OL) and ultimately myelinating oligodendrocytes (OLs). However, OPCs from aged animals have reduced differentiation ability. This disrupts myelin maintenance in the central nervous system (CNS), leading to a lack of remyelination following demyelinating injury and impaired adaptive myelination as a mechanism of learning. To uncover novel factors essential for restoring resilience in aged OPCs, we employed a data-driven approach involving the development of a computational pipeline, gSWITCH (accessible at: https://altoslabs.shinyapps.io/gSWITCH/), that allows for capture of precise dynamic gene expression patterns to pinpoint potential \'switch\' genes during lineage progression. Using gSWITCH to identify potential switch genes crucial for OPCs, we conducted a comparative analysis of gene expression in OPCs isolated from young and aged animals. This revealed a group of transcription factors with decreased expression in aged OPCs. Further analysis of transcription factor binding site enrichment in OPC switches highlighted Bcl11a, a zinc finger transcription factor that could potentially serve as a master regulator of many switch genes. Ectopic overexpression of Bcl11a in aged OPCs did not enhance their proliferation; however, it significantly enhanced their differentiation into OLs. Overexpression of Bcl11a in aged mice, followed by demyelination injury in spinal cord white matter, significantly increased the differentiation of OPCs into OLs within the injury region compared to control aged mice. Furthermore, we found that Bcl11a is absent in invertebrates and has undergone pervasive purifying selection throughout vertebrate evolution, constraining its amino-acid sequence by eliminating deleterious mutations. Our study shows that reversing the age-related decline of this evolutionarily conserved factor in aged OPCs restores their impaired capacity for differentiation.

The emergence of SARS-CoV-2 has posed significant threats to global health, particularly for the older population. Similarly, common human coronaviruses, such as HCoV-229E, which typically cause mild cold-like symptoms, can lead to severe diseases, underscoring the need to understand virus-host interactions and identify host factors contributing to viral pathogenesis and disease progression. In this study, we perform a genome-wide CRISPR knockout screen using HCoV-229E and identify UHRF1 as a potent restriction factor. Mechanistically, UHRF1 suppresses HCoV-229E infection by downregulating the expression of its cell entry receptor, APN, through promoter hypermethylation. Focused CRISPR activation screens of UHRF1-downregulated genes confirm the critical role of APN in HCoV-229E infection and identify additional genes (e.g., SIGLEC1, PLAC8, and heparan sulfate biosynthesis genes) contributing to the restrictive functions of UHRF1. Transcriptomic and single-cell RNA sequencing analysis reveal that UHRF1 expression decreases with age, negatively correlating with increased APN expression. This age-related decline in UHRF1 is validated in primary alveolar macrophages from elderly individuals, which exhibit heightened susceptibility to HCoV-229E compared to those from younger individuals. Our findings highlight UHRF1 as a key age-related host defense factor against coronavirus and provide insights into the epigenetic regulation of viral entry receptors.

A systematic investigation of aging patterns across virtually all major tissues in nonhuman primates, our evolutionarily closest relatives, can provide valuable insights into tissue aging in humans, which is still elusive largely due to the difficulty in sampling. Here, we generated and analyzed multi-omics data, including transcriptome, proteome and metabolome, from 30 tissues of 17 female rhesus macaques (Macaca mulatta) aged 3-27 years. We found that certain molecular features, such as increased inflammation, are consistent across tissues and align with findings in mice and humans. We further revealed that tissue aging in macaques is asynchronous and can be classified into two distinct types, with one type exhibiting more pronounced aging degree, likely associated with decreased mRNA translation efficiency, and predominantly contributing to whole-body aging. This work provides a comprehensive molecular landscape of aging in nonhuman primate tissues and links translation efficiency to tissue-specific aging.

The short-lived and rapidly aging African turquoise killifish, Nothobranchius furzeri GRZ is a unique model to study vertebrate aging. Current genomic and full-length transcriptomic sequencing lacks full gene annotations, resulting in poor mapping in bulk and single-cell transcriptomic studies. In our efforts to reannotate the transcriptome of the killifish telencephalon, we combined long-read (Smrt-Isoseq) and short-read transcriptome sequencing approaches. A total of 17,008 full-length isoforms, including 6763 novel ones were obtained (51 bp to 7,500 bp). The killifish telencephalon comprises 25% multi-exon genes, while over 50% are mono-exon genes. We discovered novel non-coding and coding sequences in both young and aged telencephali. We integrated long-read and RNA-seq data to construct a comprehensive transcriptome and profiled expression dynamics across the aging telencephalon. Our gene models demonstrate greater detail and accuracy than Ensembl, with more precise polyA locations. Alternative splicing analysis revealed 29 events altered with aging, which involved changes in ribosome function, gap junction and mRNA surveillance pathways. These generated resources pave the way for future functional genomic studies in this biogerontology model.

Background: Defective cardiac relaxation (diastolic dysfunction) is common in heart failure, especially with diabetes, obesity, hypertension, and ageing, and is linked to increased mortality. No effective therapy specifically targets this dysfunction. Phosphorylation of troponin I by cAMP-dependent protein kinase A (PKA) promotes relaxation, but global PKA activation affects numerous downstream targets. Here we investigated whether selective enhancement of troponin I phosphorylation could improve relaxation without widespread PKA activation. Methods: To investigate cAMP signalling with subcellular resolution we used real-time detection of cAMP levels and FRET based genetically encoded reporters targeted to specific locations combined with biochemical and genetic approaches. We applied peptide array technology to study protein-protein interaction surfaces and develop a protein-protein interaction disruptor peptide. The impact of such peptide on cardiac myocyte function was investigated in vitro, using both mouse and human primary cardiac myocytes and biochemical approaches, real-time imaging, work-loop analysis. In vivo analysis involved echocardiography and hemodynamics measurements. Results: We discovered that the cAMP-hydrolysing enzyme PDE4D9 binds troponin I and locally degrades cAMP within a nanometre-scale domain, thereby selectively regulating troponin I phosphorylation. The association of PDE4D9 with troponin I is markedly increased in cardiac disease in rodents and humans. A peptide displacing PDE4D9 from troponin I selectively elevates troponin I phosphorylation, enhances cardiomyocyte relaxation, and prevents diastolic dysfunction in a mouse heart failure model. Conclusions: Our findings define a first-in-class, mechanism-based therapeutic approach to a major, unmet contributor to heart failure.

Elucidating the impact of aging on the structure and function of neurons is key to understanding the mechanisms underlying synaptic dysfunction and ensuing susceptibility to age-related cognitive decline. The role of structural alterations in the lateral prefrontal cortex (LPFC) has been extensively addressed. In addition, numerous studies point to the importance of inflammation and the increase of oxidative stress during aging, with mitochondria as one of the key cellular organelles involved. Here, we used 3D high-resolution serial block-face scanning electron microscopy to visualize the ultrastructure of synapses on pyramidal neurons in area 46 of the LPFC in rhesus monkeys at different stages across their adult lifespan. Our results revealed a general loss of synapses with age, mainly driven by the loss of asymmetric axospinous synapses. We observed a larger bouton volume but not larger spine or postsynaptic density (PSD) surface in the aged group compared to all other groups, along with a weaker correlation between spine and synaptic size. Additionally, we found morphological changes in mitochondria in the aged compared to middle-aged and young monkeys. Altogether, our data show ultrastructural changes that suggest an improper synaptic scaling and possible mitochondrial dysfunction that might take place after middle-age. We studied the impact of curcumin as a long-term dietary supplement and found that it ameliorated some of these age-related changes at middle-age by preserving the spine and PSD morphology and their size relationship, and also mitochondrial morphology, which might allow for maintaining synaptic function during aging, resulting in a delayed cognitive decline.

Background: Interventions supporting medical care and enhancing quality of life in neurodegenerative or age-related cognitive decline are strongly needed. Electroencephalographic (EEG) neurofeedback can enable users to modulate their brain activity through real-time feedback. However, evidence for its clinical effectiveness remains inconclusive, partly due to limited personalization and insufficient task relevance in existing protocols. Objective: We tested whether personalized EEG neurofeedback supervised by deep neural networks (DNNs) can enhance cognitive performance in older adults. Methods: Fifty-seven healthy adults aged 41 to 64 (31 women), including a sham-feedback control group, completed a personalized neurofeedback protocol with DNNs fine-tuned to individual EEG patterns. The procedure included pre- and post-training assessments using a transitive reasoning task, three diagnostic sessions to adapt the DNN to each participant, and 10 neurofeedback sessions based on a gamified delayed-match-to-sample paradigm. Results: The training group showed robust gains across all three variants of the reasoning task (each p < .01), whereas the sham group improved only on the easiest variant. Groups did not differ at pretest; however, at posttest the training group outperformed the sham group on all task conditions (each p < .03), showing also a larger neural effort (lower alpha band power) and increased beta and gamma band connectivity (higher phase lag index). Conclusion: Personalized, task-oriented neurofeedback guided by individually fine-tuned DNNs can produce cognitive enhancement after relatively few sessions. The proposed Task-Pretrained, Subject-Finetuned Neurofeedback (TPSF-NF) framework is scalable to other cognitive domains in future research.

Tendon degeneration is common, and its risk increases with age both in humans and horses. Tendon regeneration and healing is limited due to inherent low cell density and vascularisation, and current treatments are insufficient as indicated by scar tissue formation and a high re-injury rate. The tendon vasculature plays a crucial role in tendon homeostasis, regeneration and healing, making it a potential therapeutic target. However, the effect of ageing on the tendon microvasculature is poorly understood. Here, we provide the first comprehensive characterisation of the tendon microvasculature. We employed high-resolution 3D imaging techniques, using micro-computed tomography (μCT) and confocal microscopy, to investigate age-related alterations in the vasculature within the equine superficial digital flexor tendon (SDFT), a functional equivalent of the human Achilles tendon. μCT analysis revealed a well-developed vascular network within the interfascicular matrix (IFM) and demonstrated significant age-associated reductions in vascular volume (70%), vessel diameter (30%) and density (74%). 3D immunolabelling showed significant reductions in MYH11- (96%) and desmin-positive (78%) volumes; however, there was a pronounced age-associated increase in von Willebrand factor (VWF)-positive volume (220%), which was accompanied by a significantly higher (249%) pericyte density. Taken together, these results indicate a loss of larger blood vessels in the IFM but an increase in small vessel formation, suggesting that neo-angiogenesis is induced in aged tendon alongside a loss of vascular homeostasis. These insights enhance our understanding of tendon ageing and may contribute to developing new therapeutic approaches for improving tendon health and repair in older individuals.

Aging not only significantly reduces the quality of life for the elderly but also poses multifaceted challenges to society. Its progression involves the synergistic interaction of multidimensional, multipathway molecular mechanisms, including mitochondrial dysfunction, oxidative stress accumulation, chronic inflammation, and genomic damage. Quercetagetin (QG), as a natural flavanol monomer, exhibits significant potential in anti-aging due to its simultaneous targeting of key aging pathways such as oxidative stress and chronic inflammation. We first evaluated QG's safety profile, finding that 0.02 mg/ml QG did not adversely affect motility, feeding, growth, and reproductive capacity in Caenorhabditis elegans (C. elegans). At this concentration, in vivo experiments using wild-type C. elegans confirmed QG's ability to extend lifespan and enhance oxidative stress resistance. The antioxidant and anti-aging effects of QG were further validated using the daf-16 mutant C. elegans DR26. Subsequently, observation of QG's impact on C. elegans mitochondrial morphology revealed significant reductions in area/perimeter and mitochondria coverage ratio following treatment. This indicates that QG treatment shifts the mitochondrial network from fusion toward fission and reduces overall mitochondrial content. QG can also improve age-related dopaminergic, 5-hydroxytryptaminergic and cholinergic neuron degeneration. Mass spectrometry metabolome analysis revealed that QG significantly affected citrate cycle and glycerophospholipid metabolism. Collectively, QG extends C. elegans lifespan by regulating redox homeostasis, DAF-16/FOXO pathways, mitochondrial homeostasis and metabolic reprogramming. This multi-target regulatory capacity positions QG as an ideal candidate molecule for anti-aging drug development.

Somatic mutation is now recognized as a cause of multiple human diseases other than cancer. Osteoarthritis (OA), a highly prevalent age-related disease, has been associated with increased chromosomal abnormalities in articular cartilage. Here we characterize the somatic mutational landscape of chondrocytes during normal aging and in affected cartilage of patients with OA. We used single-cell whole-genome sequencing to analyze single-nucleotide variants (SNVs) and small insertions and deletions (InDels) in 100 chondrocytes isolated from the cartilage of hip femoral heads of 17 research participants aged 26-90 years, including 9 patients with OA and 8 non-OA donors. Both SNVs and InDels accumulate with age in chondrocytes with a clock-like mutational signature. Surprisingly, the age-related accumulation rate in OA chondrocytes is lower than that in non-OA control chondrocytes. Differences in mutational signatures and Gene Ontology term enrichment were found between OA and non-OA control samples. In this study, to understand the role of somatic mutation in the pathogenesis of OA, we characterized somatic SNV and InDel mutations. With further progress in analytical approaches, structural variations in the chondrocyte genome are also expected to provide valuable information.

Arterial aging, marked by progressive vascular stiffening, is a contributor to cardiovascular disease. Photoplethysmography (PPG) waveforms offer an easily accessible signal of arterial function, enabling scalable assessment of arterial age at the population level. Here, we present a multimodal deep learning framework integrating raw PPG waveforms with hemodynamic features from UK Biobank participants to construct an arterial aging clock. From this model, we derived ArtAgeGap, an age-independent residual biomarker of arterial aging, which correlated with established measures of vascular stiffening, such as pulse pressure (r=0.60). ArtAgeGap was significantly elevated in individuals with a history of cardiovascular disease, and associated with diabetes (+0.93 years, 95%CI: 0.64-1.21) and hyperlipidemia (+0.49, [0.36-0.61]). In 96,615 participants followed for a median of 13 years, higher ArtAgeGap values predicted incident hypertension, major adverse cardiovascular events, and cardiovascular and all-cause mortality (hazard ratios per +1 year: 1.01-1.06), on top of chronological age. A genome-wide association study in 114,098 individuals identified 60 independent loci associated with ArtAgeGap, including variants previously associated with blood pressure (e.g. NPR3), arterial stiffness (CLCN6), aortic diameter (SLC24A3), and atherosclerosis (HDAC9), as well as 34 novel loci enriched for arterial tissue expression. Integrative analyses with transcriptomic data from human arteries prioritized 28 genes, such as RSG19 and ULK4, whose genetically proxied expression was associated with ArtAgeGap. Single-cell transcriptomic data from arterial tissue revealed strong enrichment of these genes in fibroblasts, implicating fibrotic remodeling mechanisms in arterial aging. Rare variant burden testing further implicated damaging variants in COL21A1, LMNA, TP53BP2, RXRB, and FLOT2, also converging to mechanisms related to extracellular matrix organization and fibrosis regulation. Lastly, Mendelian randomization analysis identified ArtAgeGap as an intermediate biomarker in-between vascular risk factors and outcomes, with central adiposity, higher blood pressure, and type 2 diabetes increasing ArtAgeGap, and higher ArtAgeGap elevating the risks of coronary heart disease and stroke. Together, these findings establish ArtAgeGap as a scalable PPG-based biomarker of arterial aging and provide mechanistic insights into potential therapeutic strategies to mitigate arterial aging.

Down syndrome, caused by an extra copy of Chromosome 21, causes lifelong problems. One of the most common phenotypes among people with Down syndrome is premature aging, including early tissue decline, neurodegeneration, and shortened life span. Yet the reasons for premature systemic aging are a mystery and difficult to study in humans. Here we show that chromosome amplification in wild yeast also produces premature aging and shortens life span. Chromosome duplication disrupts nutrient-induced cell-cycle arrest, entry into quiescence, and cellular health during chronological aging, across genetic background and independent of which chromosome is amplified. Using a genomic screen, we discovered that these defects are due in part to aneuploidy-induced dysfunction in Ribosome Quality Control (RQC). We show that aneuploids entering quiescence display aberrant ribosome profiles, accumulate RQC intermediates, and harbor an increased load of protein aggregates compared to euploid cells. Although they maintain proteasome activity, aneuploids also show signs of ubiquitin dysregulation and sequestration into foci. Remarkably, inducing ribosome stalling in euploids produces similar aging phenotypes, while up-regulating limiting RQC subunits or poly-ubiquitin alleviates many of the aneuploid defects. We propose that the increased translational load caused by having too many mRNAs accelerates a decline in translational fidelity, contributing to premature aging.

Cognitive impairment is a frequent outcome of chronic viral infections linked to premature aging, including HIV. The mechanisms underlying this decline remain poorly understood. Here, we identify pro-inflammatory glycan degradation, characterized by loss of sialic acid and galactose, alterations that are hallmarks of premature aging, as key contributors to HIV-associated cognitive impairment (HIV-CI). In two independent cohorts of people living with HIV, these degradative changes were enriched in individuals with cognitive impairment, particularly females, and correlated with worse cognitive performance. In both a humanized mouse model of HIV and Eco-HIV, a complementary model that allows behavioral testing, pharmacological inhibition of glycan degradation with sialidase inhibitors prevented virally induced inflammation, immune activation, accelerated aging, and memory deficits. These findings implicate glycan degradation as a contributor to inflammation and cognitive impairment in HIV and highlight glycan-preserving therapies as a promising strategy to mitigate inflammation, premature aging, and cognitive decline during viral infections.

Stroke, caused by interrupted brain blood supply, predominantly affects the elderly. Epidemiological data indicate that over 70% of ischemic strokes occur in individuals aged 65 and above, and older patients are more likely to experience worse functional recovery and higher mortality rates. Most models use young animals, limiting clinical relevance for aged patients. Studying aged animals is more clinically applicable, especially since older patients often experience severe strokes. We selected a permanent middle cerebral artery occlusion (pMCAO) model to reflect strokes where reperfusion therapy is not achieved. A significant proportion of stroke patients (particularly older individuals) do not receive or benefit from thrombolysis/thrombectomy, leaving them with permanent arterial occlusion. In our aged mice model, pMCAO provides a stringent test of neuroprotective efficacy under conditions of sustained ischemia, which can illuminate melatonin's potential benefits in severe, unmanaged stroke. Melatonin, a potent antioxidant, has been shown to reduce infarction volume and improve neurobehavioral and electrophysiological recovery in ischemic stroke models. In this study, our objective was to assess the neuroprotective and neuroplasticity effects of melatonin as reflected by dendritic spine density and arborization in middle-aged mice (12-13 months old), a relevant model for aging-related stroke pathology. In this study, "middle-aged" refers to 12-13-month-old ICR mice, equivalent to approximately 40-50 human years. Twelve-month old male ICR mice subjected to pMCAO were treated with melatonin (5 mg/kg) or a vehicle before undergoing surgery. Neurobehavioral performance was assessed 24 h post-surgery, and brain tissues were collected for Golgi-Cox staining to assess stroke-induced neuronal dendritic damage and neuroplasticity. Melatonin treatment notably decreased infarct volume and neuronal degeneration, while enhancing neuron survival, increasing dendritic spine density, and promoting functional neuroplasticity in ischemic regions and promoting better neurobehavioral recovery compared to the vehicle controls (P < 0.05). In addition to evaluating infarct volume and synaptic plasticity, we assessed lipofuscin accumulation as a histological marker of neuronal aging and oxidative stress. Melatonin treatment reduced lipofuscin deposits, suggesting a potential role in attenuating age-related neurodegeneration. The administration of melatonin also resulted in a significant increase in dendritic spine density (P < 0.05) within the second- and third-order basilar dendrites of pyramidal neurons in layers II-III and III-IV of the penumbra, as well as in layer V-VI of both the ipsilateral (ischemic) and contralateral (nonischemic) cortex, when compared to vehicle controls (P < 0.05). In addition, melatonin treatment enhanced dendritic arborization in pyramidal neurons within layers II-III and III-IV of the ipsilateral cortex (P < 0.05). Furthermore, melatonin upregulation brain-derived neurotrophic factor (BDNF), growth-associated protein 43 (GAP-43) and synaptosomal-associated protein 25 (SNAP-25) expression post-insults. In this study, melatonin showed significant neuroprotective effects after ischemic stroke and enhanced neuroplasticity in middle-aged mice, suggesting its potential application in aging-related stroke therapy.

Aging profoundly impacts bone homeostasis and regeneration, yet the cellular and molecular mechanisms underlying periosteal aging remain poorly understood. Using single-cell RNA sequencing, we profiled the periosteum of 3-, 9-, and 18-month-old mice, which revealed age-related shifts in progenitor, neutrophil, and macrophage subpopulations. Aging reduced mesenchymal cell populations and impaired osteogenic potential, may contribute to periosteal homeostasis. Periosteal progenitor subsets exhibited distinct aging trajectories: Dpt⁺ fibrous-layer cells undergoing early senescence, while Postn⁺ progenitors showed osteogenic decline. Aging also shifted immune profiles, increasing inflammatory Cd38

Intestinal function and white adipose tissue (WAT) function deteriorate with age, but whether and how their deterioration is intertwined remains unknown. Increased gut permeability, microbiota dysbiosis, and aberrant immune microenvironment are the hallmarks of intestinal dysfunctions in aging. Here, we show that subcutaneous WAT dysfunction triggered aging-like intestinal dysfunctions in mouse models. Removal of inguinal subcutaneous WAT (iWAT) increased intestinal permeability and inflammation and altered gut microbiota composition as well as susceptibility to pathogen infection in mouse models. These intestinal dysfunctions were accompanied by a reduction of immunoglobulin A-producing (IgA-producing) cells and IgA biosynthesis in the lamina propria of the small intestine. Retinoic acid (RA) is a key cargo within iWAT-derived extracellular vesicles (iWAT-EVs), which, at least in part, elicits IgA class-switching and production in the small intestine and maintains microbiota homeostasis. RA content in iWAT-EVs and intestinal IgA biosynthesis are reduced during aging in mice. Replenishment of "young" iWAT-EVs rejuvenates intestinal IgA production machinery and shifts microbiota composition of aged mice to a "youth" status, which alleviates leaky gut via RA. In conclusion, our findings suggest that iWAT-EVs with RA orchestrate IgA-mediated gut microbiota homeostasis by acting on intestinal B cells, thereby maintaining intestinal health during aging.