Longevity Papers

Autophagy maintains cellular homeostasis through lysosomal degradation of cytoplasmic components, yet how prolonged autophagy activation reshapes organelle architecture remains poorly understood. Here we identify a previously unrecognized form of endoplasmic reticulum (ER) remodeling induced by chronic mTOR inhibition. This process triggers the formation of autolamellasomes: multilamellar, ER-derived structures that mediate bulk ER degradation. Unlike canonical ER-phagy, autolamellosome biogenesis requires the core autophagy machinery but is independent of known ER-phagy receptors. Cryo-ET, CLEM, and in vitro reconstitution reveal that they arise from autophagy-dependent assembly and compaction of fragmented ER into concentric stacks, which are then engulfed by lysosomes. Autolamellasomes occur at low levels constitutively, but accumulate in senescent cells and HGPS fibroblasts, linking sustained mTOR suppression to aging and ER/lysosomal homeostasis. This work clarifies the origin of intra-lysosomal membrane whorls and introduces a cell-free system for studying autophagy-driven membrane remodeling, connecting nutrient sensing, lipid catabolism, and aging.

Measuring biological age typically requires invasive and costly procedures. To address this, the MoveIt! Age Score was developed: a simple, scalable, and interpretable aging clock that predicts biological age using only wearable-derived steps data. MoveIt! Age was trained on steps data from the United States National Health and Nutrition Examination Survey (NHANES), using chronological age, maximum step count, and step count variability to predict PhenoAge, a blood biochemistry biological age score. MoveIt! Age performance was evaluated in two independent cohorts: Mitochondria and Muscle Health in Elderly (MitoHealth; N = 55; healthy young adults or older adults from the Netherlands) and Restoring Health of Acutely Unwell Adults (RESORT; N = 145; geriatric rehabilitation inpatients from Australia). In RESORT, MoveIt! Age was assessed and compared to SenoClock-BloodAge and PhenoAge (hematological aging clocks). Delta age was the predicted biological age minus chronological age. In the NHANES testing dataset, MoveIt! Age demonstrated high predictive accuracy of chronological age (r = 0.97, RMSE = 5.4 years) and was more significantly associated with mortality than PhenoAge. In MitoHealth, delta MoveIt! Age showed differences between young adults and older adults who were normal, healthy, or health-impaired, with MoveIt! Age more significantly associated with muscle NAD

Alternative splicing is a key mechanism for transcriptomic diversity, but how isoforms map to specific cell types in bulk tissues remains unclear. We present Sciege, a multimodal method that integrates bulk short-read RNA-seq with single-cell and long-read data to estimate cell type-specific isoform distributions. Through simulations, we demonstrate that Sciege accurately estimates isoform abundances and identifies differentially abundant transcripts through statistical tests. Applied to seven tissues in GTEx and brain tissue in ROSMAP datasets, Sciege generates a first-to-date multi-tissue isoform atlas and reveals isoform changes linked to cell types, aging, and Alzheimer\'s disease. Validation with external cohorts and experimental data confirms our findings. Notably, we identify upregulation of the MAPT-010 isoform in AD inhibitory neurons, consistent with known methylation signatures. Our approach demonstrates the value of integrating RNA-seq data to study cell type-specific splicing and provides a foundation for further genetic and functional studies of alternative splicing across biological contexts.

Nicotinamide/nicotinic acid mononucleotide adenylyltransferase 2 (NMNAT2) is a crucial enzyme for synthesizing nicotinamide adenine dinucleotide (NAD) and plays a vital role in neuronal health. NMNAT2 mRNA levels correlate positively with cognitive function in older adults but decline after injuries or proteinopathies. In this study, we used chromosome conformation capture followed by high-throughput sequencing (4C-seq) to unbiasedly identify NMNAT2 regulatory regions throughout the human genome. Using various bioinformatics analyses with these genomic regions, referred to as interactomes, we identified NMNAT2-associated genes and putative transcription factors (TFs). NMNAT2 transcription increases in SH-SY5Y cells when they differentiate into a neuron-like state. Excitingly, our 4C-seq data revealed distinct sets of interactomes interacting with the NMNAT2 promoter in undifferentiated versus neuron-like SH-SY5Y cells. Using the Religious Orders Study and the Rush Memory and Aging Project (ROSMAP) snRNA-seq data, we showed that the expression levels of many NMNAT2-associated genes are significantly correlated with NMNAT2 transcription in human neurons. Our biological validation studies confirmed the requirement of two specific genomic regions and four TFs, including cyclic AMP-dependent transcription factor ATF4, cyclic AMP-dependent transcription factor ATF-6 alpha (ATF6), transcription factor SOX11, and heat shock factor protein 1 (HSF1), in NMNAT2 transcription. ATF4 has been identified as an injury-responsive TF, whereas HSF1 is modulated by protein stress. Together, our study identifies distinctive genomic loci containing NMNAT2 regulatory elements in undifferentiated versus neuron-like SH-SY5Y cells, NMNAT2-associated genes, and putative NMNAT2-TFs.

Radiation-induced lung injury (RILI) is a dose-limiting toxicity of thoracic radiotherapy driven by mitochondrial damage-mediated oxidative stress, persistent DNA damage, and senescence, which together destabilize the alveolar-interstitial niche and promote fibrosis. Here, we identify Foenumoside B (FSB), a natural saponin from Lysimachia foenum-graecum, as a dual-action modulator that preserves mitochondrial quality and restores systemic redox homeostasis to attenuate RILI. In a murine total lung irradiation model (20 Gy), oral FSB (10 mg/kg/day) mitigated inflammation and fibrotic remodeling, improved pulmonary mechanics and arterial blood gases, and exhibited no overt hepatorenal toxicity. Mechanistically, FSB activated PINK1/Parkin-dependent mitophagy in alveolar epithelial cells. Pharmacologic autophagy blockade (3-MA) or PINK1 silencing abrogated these benefits, increasing mtROS, γH2AX foci, comet tail moments, and p16/p21 expression, and reducing cell viability, thereby confirming mitophagy as indispensable for FSB's cytoprotection. Molecular docking analysis demonstrates that FSB binds to the catalytic α1 and α2 subunits of AMPK, thereby significantly increasing the p-AMPK/AMPK ratio. Upon pharmacologic inhibition of AMPK, the FSB-mediated improvements in mitophagy, mitochondrial function, redox homeostasis, and tissue protection are markedly attenuated, indicating that FSB's biological effects rely on AMPK activation. FSB also restored Nrf2/HO-1 signaling and antioxidant capacity. Co-IP/ChIP showed AMPK directly associates with Nrf2, enhances its phosphorylation and ARE binding at the HO-1 promoter, and weakens Keap1-mediated degradation. Overall, FSB suppresses reactive oxygen species at their mitochondrial source and, through AMPK-driven mitophagy and Nrf2 activation, enhances endogenous antioxidant defenses, providing a translatable strategy to preserve alveolar architecture during radiotherapy.

The p38 mitogen-activated protein kinase has a well-characterized role in modulation of inflammatory processes throughout the body. In the central nervous system, p38 is primarily studied within neurons and microglia, most commonly in the context of neurological insult. The present study was designed to determine its function in astrocytes during non-pathological aging. We generated a conditional knockout model in which a tamoxifen-inducible Aldh1l1 promoter drives Cre recombinase expression in mice with exon 1 of the p38α gene flanked by loxP sites. Knockout of astrocyte p38α was achieved via tamoxifen administration in young sexually mature mice at 3-4 months old. Animals were subsequently aged to 21-24 months prior to performing electrophysiological, immunohistochemical, and biochemical analyses. We found that early loss of astrocyte p38α was associated with a reduction in hippocampal neuroinflammation and concomitant enhancement of synaptic strength in aged female mice. In subsequent experiments in younger animals, the knockout reduced peripheral GFAP levels and increased non-synaptic mitochondrial uncoupling. These findings indicate that astrocyte p38α has wide-ranging effects on brain metabolism, inflammation, and synaptic function during the course of normal aging, including release of GFAP from the central nervous system to the periphery. Follow-up studies exploring the role of astrocyte p38α in various age-associated neuropathological contexts are warranted.

Short tandem repeats (STRs) are highly abundant in the human genome and their age-related somatic instability is emerging as a pivotal pathomechanism in repeat expansion disorders. Nevertheless, currently no analysis tool exists for genome-wide profiling of STR somatic instability. Here, we present searchSTR, a novel computational framework that enables accurate STR genotyping and somatic instability quantification from both whole-genome and targeted sequencing data. Applying this approach, we analyzed STR variants from whole-genome sequencing data of the 1000 Genomes Project (n=3,202) and targeted deep-sequencing data of the population-based Rhineland Study (n=2,974). We provide a comprehensive multiancestry genome-wide reference panel of STR variants and their somatic instability, covering more than 1.4 million STRs across 26 populations. Remarkably, STR somatic instability at many loci was robustly associated with age, sex, brain morphology and markers of neurodegeneration. These findings reveal a crucial role for STR somatic instability as an age-dependent modifier of brain structure.

The repressor element 1-silencing transcription factor (REST), or neuron-restrictive silencer factor (NRSF), is crucial for gene regulation since it binds to chromatin and recruits chromatin-modifying enzymes. Acting as a regulatory hub, REST orchestrates neurogenesis, neuronal differentiation, and the preservation of neuronal identity by regulating a broad network of target genes across stem cells, non-neuronal cells, and neurons. These targets influence critical processes such as axonal growth, vesicular transport, neurotransmitter release, and ion conductance. An important feature of normal aging in cortical and hippocampal neurons is REST induction, where it contributes to extended longevity by repressing genes linked to neuronal excitability and stress vulnerability. However, REST's role in neurodegenerative diseases remains complex and context dependent. Variations in its expression and subcellular localization, including cytoplasmic translocation or loss, have been implicated in the pathology of disorders like Alzheimer's disease, Parkinson's disease, Huntington's disease, schizophrenia, and epilepsy. Given its broad regulatory functions, REST has emerged as an attractive therapeutic target. Strategies such as microRNA modulation, small molecule inhibitors, and complex-disrupting compounds have been explored, each offering unique opportunities and challenges. Understanding REST's molecular mechanisms and disease-specific functions is critical for identifying novel therapeutic interventions. This review provides a comprehensive analysis of REST's role in aging and neurodegeneration, highlighting its regulatory networks, disease relevance, and recent therapeutic strategies targeting REST, with an emphasis on their potential for clinical translation.

Direct reprogramming of fibroblasts into induced cardiomyocytes (iCMs) offers a regenerative strategy for heart repair, but efficiency declines in adult and aged cells. Transcriptomic and epigenetic profiling identified cellular senescence as a major barrier limiting cardiac fibroblast (CF) plasticity and cardiogenic conversion. Postneonatal fibroblasts exhibited impaired activation of cardiac gene programs and persistent expression of fibrotic and inflammatory signatures. A loss-of-function screen identified Nr4a3 as a central repressor. Nr4a3 overexpression promoted senescence and suppressed iCM induction, whereas knockdown enhanced reprogramming in murine and human senescent CFs. Mechanistically, Nr4a3 depletion remodeled the chromatin landscape from a fibrotic and inflammatory state to a regenerative cardiac program. Blocking downstream Cxcl14 restored reprogramming in refractory fibroblasts. In vivo, Nr4a3 knockdown improved heart function following myocardial infarction. These findings established cellular senescence as a major barrier to cardiac reprogramming and identified Nr4a3 and its effectors as potential targets to enhance heart regeneration.

Cellular senescence, a hallmark of ageing, drives tissue dysfunction by promoting inflammation and fuelling disease. Yet, the dynamics of senescent cell accumulation across tissues and their cell type identity remain poorly understood. Here, we introduce the first, single-cell, protein-level approach, combining multiple senescence markers for the identification and quantification of senescent cells across multiple tissues in mice and in human PBMCs. Applying this method, we reveal widespread but heterogeneous changes in senescence marker expression across cell types and tissues. The cells we identify as senescent displayed transcriptomic senescence signatures, providing a direct molecular link between protein- and mRNA-level detection of senescence. Importantly, senescence accumulation was strongly coordinated within organs but showed little correlation across them, supporting the idea of a tissue specific progression of ageing. These findings refine our understanding of the tissue-specific dynamics of senescence accumulation with age, and provide a framework for evaluating diverse therapeutic interventions.

In demyelinating diseases like multiple sclerosis (MS), efficient remyelination is critical for functional recovery. Remyelination efficiency declines with age, and is linked to progressive disability. The gene regulatory network underlying remyelination, and how it is altered with aging, remains unclear. Here we present a comparative single-nucleus RNA and ATAC sequencing analysis of remyelination in young and aged mice. We identified gene modules dynamically expressed throughout oligodendrocyte differentiation, revealing age-dependent changes in key processes related to myelination. Multi-omic analysis allowed us to map the regulatory network driving efficient remyelination within oligodendrocyte lineage cells in young mice. We highlight key transcription factors in the network dysregulated with age, and we describe similar dysregulations in MS lesions. Modifying the expression of these transcription factors in primary oligodendrocyte progenitor cells impacts differentiation. These findings provide a foundational understanding of this regenerative process in the context of aging and in chronic demyelinating diseases.

Aging induces progressive changes that heighten the central nervous system's (CNS) vulnerability to neurological disorders. Emerging evidence suggests that nicotine, an alkaloid primarily derived from plants of the genus Nicotiana, may offer neuroprotective effects against aging. However, its role in maintaining mitochondrial homeostasis during aging remains unexplored. In this study, we demonstrated that nicotine improved recognition memory in aging rats. Additionally, it increased dopamine (DA) levels and upregulated PSD95 and synaptophysin expression in the hippocampus of aged rats. Notably, RNA sequencing (RNA-seq) analysis revealed that nicotine promoted mitochondrial homeostasis in the hippocampus. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that genes enriched in the nicotine-treated group were predominantly associated with axon guidance, cholinergic, GABAergic, and dopaminergic synapses. Similarly, Gene Ontology (GO) enrichment analysis highlighted the involvement of these genes in key biological processes, including learning, memory, and axon guidance. Moreover, nicotine reversed aging-associated gene expression patterns linked to mitochondrial function. Consistently, it upregulated peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and Parkin expression both in vivo and in vitro, while also enhancing mitochondrial respiratory capacity in SH-SY5Y cells. Collectively, our findings reveal that nicotine promotes hippocampal PGC-1α expression and mitophagy, thereby preserving mitochondrial homeostasis during aging. This study suggests a potential strategy for mitigating age-related memory decline.

Glaucoma is associated with ocular hypertension and lowering intraocular pressure is a key objective of glaucoma therapies. Recent studies have established a role for the Schlemm\'s canal endothelium in this pressure increase and have shown it to have a unique, lymphatic-like, hybrid phenotype. However, the role of these lymphatic phenotypes in the adult canal remains uncertain. Long-term functional studies have been limited by systemic importance of lymphatic genes and lack of Schlemm\'s canal-specific animal models. Here, we designed and validated a strategy using 4OH-tamoxifen-loaded nanocarriers to generate targeted, Schlemm\'s canal specific knockout mice lacking lymphatic phenotypes. Using this system, we selectively deleted Prox1, the master transcription factor governing lymphatic fate. Within four weeks, intraocular pressure significantly increased, and ocular hypertension was maintained for at least 24 weeks. Unlike lymphatic vessels, which degenerate following Prox1 deletion, Schlemm\'s canal reverted to a less functional vein-like phenotype with no change in size or morphology. These results highlight the utility of nanocarriers for tissue-specific genetic recombination and demonstrate that changes in lymphatic phenotypes alter intraocular pressure, providing new targets for glaucoma therapy. Moreover, as we found that PROX1 was downregulated with age in human Schlemm\'s canal, these canal-specific conditional Prox1 knockout mice are a valuable new adult-onset model of ocular hypertension that captures key features of age-related human disease.

Cellular senescence is a primary driver of aging, where damaged or senescent cells (SnCs) continuously accumulate in the body, altering the local tissue environment and causing various pathologies in different organs or tissues, offering brand-new diagnostic and therapeutic possibilities for aging-related disease. This review begins by discussing the multiple molecular mechanisms of cellular senescence. We mainly focus on the therapeutic strategies and their clinical applications targeting cellular senescence, where senolytic and senomorphic drugs are currently two main categories of anti-aging therapies. Besides, nicotinamide adenine dinucleotide (NAD

Entropy, a measure of disorder and randomness, is an essential feature of thermodynamics, chemistry, and information theory, but there has been little study of entropy in human aging. Entropy arises from random molecular interactions or other forms of damage and will manifest at all levels of human biology. It should also progress in concert across many systems and increase the risk of numerous aging-related conditions. Illustrating these principles, research by Hong in this issue of Aging Cell applies Mahalanobis distance to quantify entropy in electrocardiograms showing that entropy in one system predicts aging-related outcomes-fracture and mortality-beyond the heart. Important issues for research on entropy and human aging include the best methods for quantifying entropy and whether the development of entropy can be slowed or reversed in humans.

Despite extensive research on life-extending interventions, rigorous statistical techniques to determine their impact on compression of morbidity (CoM) are rarely used. We present a case example of an analytical method for examining the effect of life-extending dietary interventions on CoM by comparing the rates of decline in vitality and survival toward the end of life. Using data from previous experimental studies in mice, we calculated the average rate of vitality decline by fitting exponential decay models to individual vitality trajectories and compared this rate with the rate of survival decline estimated from Cox proportional hazards model. The results showed that, surprisingly, the life-extending interventions failed to compress morbidity. Instead, the models suggested a potential expansion of morbidity with the interventions, particularly for chronic caloric restriction, as evidenced by a greater difference between the rates of vitality decline and survival decline in the intervention group than in the control group. The results further showed age-dependent effects, with interventions likely to demonstrate CoM at very old ages. These findings challenge the assumption that lifespan extension necessarily compresses morbidity, highlighting the need to consider lifespan, healthspan, and CoM as endpoints when evaluating anti-aging interventions. We do not claim that life-extending interventions categorically fail to achieve CoM; rather, we demonstrate how a rigorous statistical approach can be applied to test the CoM hypothesis. Our framework offers a valuable tool for future studies, and further refining this method will be crucial to determine under which circumstances lifespan extension leads to CoM. The potential to choose from multiple analyses of CoM calls for leadership in the geroscience community both to standardize the nomenclature so that different CoM analysis approaches can be communicated clearly and to establish a "default" CoM analysis for everyone to use in addition to their analyses of choice, thus facilitating comparisons and meta-analyses across studies.

While biological age scores have been shown to characterize aging by estimating chronological age based on physiological biomarkers, interactions between different age scores are largely unknown. To study this, large-scale multi-modal data are crucial. However, such data are scarce as population-based cohorts are generally restricted in sharing their data. Here, we employ federated learning to study the relationship between the two types of biological age scores: BrainAge based on brain MRI and MetaboAge based on metabolites. Using three large population-based cohorts, we trained a federated deep learning model to estimate BrainAge and compared its performance to models trained in a single cohort. The federated BrainAge model yielded significantly lower error for age prediction across the cohorts than locally trained models. Harmonizing the age interval between cohorts further improved BrainAge accuracy. Subsequently, we compared BrainAge and MetaboAge by performing association analysis and survival analysis for dementia and mortality prediction to further characterize both scores. The association analysis showed a weak association between BrainAge and MetaboAge, while the survival analysis indicated complementary predictive values for the mortality risk of the two scores. Federated learning has been shown to be a valuable technique for enabling the use of research cohorts that are restricted in data sharing. We conclude that BrainAge and MetaboAge act synergetically for the prediction of time to all-cause mortality, and both aging scores capture different aspects of the aging process.

Aging substantially increases susceptibility to sepsis, yet the underlying mechanisms of immune dysfunction in the elderly remain incompletely understood. Polymicrobial sepsis was induced in young and aged male mice via cecal ligation and puncture (CLP). Bone marrow from four groups (Y-Sham, n = 2; Y-CLP, n = 3; A-Sham, n = 2; A-CLP, n = 3) was analyzed by single-cell RNA sequencing and intercellular communication inferred via CellChat. Age-related immune changes were evaluated, and Transwell assays were used to assess myeloid cell migration. Aged septic mice showed worsened organ damage and systemic inflammation, with reduced adaptive (18.7% vs. 41.3%) and increased innate immunity (58.8% vs. 37.7%, A-CLP vs. Y-CLP). Neutrophil chemotaxis was impaired; monocytes and macrophages adopted a hyperinflammatory yet functionally exhausted phenotype; dendritic cells showed increased antigen presentation with diminished mobility; B cell maturation was disrupted with regression to earlier developmental stages; and T cells shifted toward stress-responsive and regulatory programs. We identified a cluster-specific expansion of HSCs in aged sepsis (39.8% vs. 31.2% in A-CLP vs. Y-CLP) with impaired Lgals9-Cd44-mediated intercellular communication. Myeloid cell migration was impaired in A-CLP but partially restored by Lgals9-Cd44 activation. This study presents a comprehensive single-cell map of bone marrow immune dysfunction in aged sepsis and identifies impaired HSC-myeloid communication as a critical mechanism driving immune failure. Therapeutically targeting the Lgals9-Cd44 axis may restore immune coordination in elderly sepsis, although its clinical feasibility and safety remain to be validated.

Aging encompasses low-level inflammation and motor decline. Astrocytes are neuroregulatory glial cells that change in aging, particularly in the cerebellum, which is essential for movement coordination. Regulation and functionality of cerebellar astrocytes in aging is unknown. We show that antiviral type I Interferons (IFN-I) drive motor deficits and regional astrocyte aging. Transcriptomics reveal that cerebellar astrocytes, but not cortical, exhibit an antiviral state that intensifies with age, with increased expression of Stat1. Aged mice display motor deficits similar to humans that improve after peripheral IFN-I receptor neutralization, whereas astrocyte Stat1 induces motor deficits during chronic inflammation in adults. While strong systemic inflammation induces astrocyte antiviral state, in aging, chromatin de-repression of Stat1 and nucleotide sensors in cerebellar astrocytes amplifies local IFN-I signaling. We identify functional interaction between a classical immune pathway and astrocytes, representing an actionable strategy to preserve motor function in aging.

Healthspan, the disease-free period of life, has become a central focus in aging research. Cuscuta chinensis seed and Eucommia ulmoides bark extracts, two traditional Chinese medicine (TCM) remedies, have shown promising healthspan-extending effects in Caenorhabditis elegans. In this study, RNA-seq analysis of aged worms treated with these extracts revealed significant transcriptomic alterations. Gene ontology and KEGG pathway analyses indicated upregulation of genes involved in immune defense, lysosomal function, and protein homeostasis, which may underlie the shared phenotype of enhanced stress resistance and lifespan extension. Beyond these effects, C. chinensis further improved multiple health parameters. Consistent with its broad spectrum of phenotypes, C. chinensis induced extensive transcriptomic remodeling involving over 3000 differentially expressed genes. Modulating collagen-, unc-, and muscle-related genes may explain improved locomotion, while upregulation of mec genes could contribute to enhanced mechanosensation. Notably, far-3, encoding a fatty acid- and retinol-binding protein, was upregulated more than 150-fold, and RNA interference assays demonstrated that FAR-3 is necessary for C. chinensis-induced healthspan improvement. Furthermore, C. chinensis influenced genes linked to antagonistic pleiotropy and insulin-like signaling, suggesting a systemic, hormesis-driven reprogramming of aging processes. Together, these findings uncover both shared and distinct molecular mechanisms through which C. chinensis and E. ulmoides promote healthspan in C. elegans.

Telomerase, crucial for maintaining telomere integrity and genomic stability, is typically silenced in somatic cells with advancing age. In this study, we identify circHERC1 as a regulator of telomerase reverse transcriptase (TERT) transcription. Specifically, circHERC1 binds to the TERT promoter, facilitating the recruitment of RNA polymerase II and c-Fos, thereby activating TERT expression. Notably, circHERC1 expression exhibits a decline with age, which correlates with reduced telomerase activity. Restoration of circHERC1 expression enhances telomerase activity, promotes telomere elongation, and reverses aging-associated phenotypes. Furthermore, delivery of circHERC1 using adeno-associated virus vectors or extracellular vesicles effectively restores telomerase activity, preserves telomere integrity, and mitigates senescence. This intervention leads to improvements in cognitive function, physical performance, and a reduction in inflammation. These findings highlight the important role of circHERC1 in telomerase regulation and the aging process, positioning it as a potential therapeutic target for antiaging interventions.

Global population aging highlights frailty as a critical health concern, yet its genetic basis remains poorly understood. We employed Mendelian randomization (MR) and National Health and Nutrition Examination Survey (NHANES) to examine causal relationships between frailty index (FI) and 36 urological diseases, investigating shared genetic mechanisms. The FI was calculated using genome-wide association data, and bidirectional MR analysis with multiple statistical methods was applied to investigate causal links between FI and 36 urological diseases. Complementary observational analyses using NHANES and generalized summary MR validation were conducted, followed by genetic correlation assessments, genome annotation, and metabolomic explorations to identify mediating pathways. MR analysis identified a significant causal association between FI and renal tubule-interstitial disease, chronic kidney diseases (CKDs), diabetes with renal complications, renal failure, and acute kidney injury. Reverse MR analysis indicated a bidirectional causal relationship between FI and acute renal failure, as well as CKD and type 1 diabetic kidney disease. NHANES data confirmed FI as an independent risk factor for CKD and renal failure. Genetic linkage analyses identified strong regional correlations between FI and CKD/renal failure within the chromosome 6 locus (31,571,218-32,682,664). Genome-wide analyses uncovered 103 novel single-nucleotide polymorphism with pleiotropic effects on the frailty-urinary disease relationship. Mediation analyses implicated the complement pathway (C2), SLITRK1, and 4-methylhexanoylglutamine as putative mediators of FI effects on CKD and kidney failure. This study elucidates the bidirectional causal relationship between frailty and CKD, while identifying novel genetic variants and metabolic pathways. These findings provide a molecular basis for developing personalized therapeutic strategies targeting both frailty and urological disorders.

Biological age (BA) and its residual relative to chronological age are popularly used to quantify individual aging. Although these residuals independently predict age-related health outcomes, conventional BA measures often lack robustness in heterogeneous populations, and their residuals are not directly derivable in clinical practice. To address these limitations, we introduce the Gompertz law-based residual (GOLD-R) framework, a method designed to directly estimate BA residuals and optimized for cross-sectional data. We demonstrated the applicability and robustness of GOLD-R across multiple data types and populations. First, training on DNA methylation data from the EWAS Data Hub, the framework outperformed established epigenetic clocks in predicting mortality in a pan-cancer dataset. Then, applied to UK Biobank proteomics data, GOLD-R generated organismal and organ-specific aging measures that proved more robust than conventional age-prediction approaches in forecasting incident diseases and mortality. Finally, extending the analysis to clinical biomarkers using the NHANES and HRS, we found that GOLD-R residuals, derived from clinical biomarkers, surpassed those from both epigenetic and phenotypic clocks in performance. In summary, our findings establish GOLD-R as a robust algorithm for biological age estimation, providing a practical tool for both research and clinical applications.

Circulating non-cellular factors, such as plasma proteins, contribute to various features of aging. To determine the impacts of endogenous circulating factors on human age-related bioenergetic decline, we treated primary human fibroblasts with serum samples representing the adult life-course. Our results demonstrate that the maximal mitochondrial bioenergetic capacity of fibroblasts treated with serum is negatively correlated with the chronological and epigenetic age of the serum donor. Using targeted proteomics, we identified plasma proteins associated with the bioenergetic effects of serum. We then utilized elastic net, a linear regression modeling technique, to derive a novel proteomic signature of age-related mitochondrial differences. MitoAge is a 25-protein signature of age-related mitochondrial health that predicts the systemic bioenergetic effects of circulating factors and is related to differences in physical function across human aging. Signatures that report on cellular hallmarks of aging, such as mitochondrial function, represent a new generation of mechanistically-informed biomarkers of biological aging.

Microbiota-derived metabolites have emerged as key regulators of longevity. The metabolic activity of the gut microbiota, influenced by dietary components and ingested chemical compounds, profoundly impacts host fitness. While the benefits of dietary prebiotics are well-known, chemically targeting the gut microbiota to enhance host fitness remains largely unexplored. Here, we report a novel chemical approach to induce a pro-longevity bacterial metabolite in the host gut. We discovered that wild-type Escherichia coli strains overproduce colanic acids (CAs) when exposed to a low dose of cephaloridine, leading to an increased life span in the host organism Caenorhabditis elegans. In the mouse gut, oral administration of low-dose cephaloridine induced transcription of the capsular polysaccharide synthesis (cps) operon responsible for CA biosynthesis in commensal E. coli at 37 °C, and attenuated age-related metabolic changes. We also found that low-dose cephaloridine overcomes the temperature-dependent inhibition of CA biosynthesis and promotes its induction through a mechanism mediated by the membrane-bound histidine kinase ZraS, independently of cephaloridine's known antibiotic properties. Our work lays a foundation for microbiota-based therapeutics through chemical modulation of bacterial metabolism and highlights the promising potential of leveraging bacteria-targeting drugs in promoting host longevity.

Early-life psychosocial stress is increasingly recognized as a contributor to accelerated biological aging and health disparities, yet its impact during young adulthood remains underexplored. Existing studies often focus on one or two dimensions of stress exposure and rely on retrospective assessments. Utilizing data from a longitudinal cohort initiated in 1989, we aim to examine the impact of early life psychosocial stress on accelerated aging in young adulthood, as well as its potential contribution to health disparities between Black and White Americans. Participants included 470 individuals (223 Black and 247 White Americans) with DNA samples collected at age > 20 years. Psychosocial stress exposures in the first 20 years of life were assessed prospectively using validated instruments across individual, family, and neighborhood domains. DunedinPACE, a novel biomarker of the pace of aging, was calculated from DNA methylation data generated from peripheral blood using the Illumina 450K array. The joint effect of early life psychosocial factors on DunedinPACE and the relative importance of each stressor were estimated using the Weighted Quantile Sum (WQS) approach. Mediation analysis was conducted to evaluate the contribution of early life stress to racial disparities in aging.

Gut microbes play a crucial role in modulating host lifespan. However, the microbial factors that influence host longevity and their mechanisms of action remain poorly understood. Using the expression of Caenorhabditis elegans FAT-7, a stearoyl-CoA 9-desaturase, as a proxy for lifespan modulation, we conduct a genome-wide bacterial mutant screen and identify 26 Escherichia coli mutants that enhance host lifespan. Transcriptomic and biochemical analyses reveal that these mutant diets induce oxidative stress and activate the mitochondrial unfolded protein response (UPRmt). Antioxidant supplementation abolishes lifespan extension, confirming that oxidative stress drives these effects. The extension of lifespan requires the oxidative stress response regulators SKN-1, SEK-1, and HLH-30. Mechanistically, these effects are linked to reduced iron availability, as iron supplementation restores FAT-7 expression, suppresses UPRmt activation, and abolishes lifespan extension. Iron chelation mimics the pro-longevity effects of the mutant diets, highlighting dietary iron as a key modulator of aging. Our findings reveal a bacterial-host metabolic axis that links oxidative stress, iron homeostasis, and longevity in C. elegans.

Insulin/insulin growth factor signaling is a conserved pathway that regulates lifespan. Yet, long-lived loss-of-function mutants often produce insulin-resistance, slow growth, and impair reproduction. Recently, a gain-of-function mutation in the kinase insert domain (KID) of the Drosophila insulin/IGF receptor was seen to dominantly extend lifespan without impairing insulin-sensitivity, growth and reproduction. This substitution occurs within residues conserved in mammalian insulin receptor (IR) and insulin growth factor-1 receptor (IGF-1R). We produced two knock-in mouse strains that carry the homologous KID Arg/Cys substitution in murine IR or IGF-1R, and we replicated these genotypes in human cells. Cells with heterodimer receptors of IR or IGF-1R induce receptor phosphorylation and phospho-Akt when stimulated with insulin or IGF. Heterodimer receptors of IR fully induce pERK but ERK was less phosphorylated in cells with IGF-1R heterodimers. Adults with a single KID allele (producing heterodimer receptors) have normal growth and glucose regulation. At four months, these mice variably display hormonal markers that associate with successful aging counteraction, including elevated adiponectin, FGF21, and reduced leptin and IGF-1. Livers of IGF-1R females show decreased transcriptome-based biological age, which may point toward delayed aging and warrants an actual lifespan experiment. These data suggest that KID mutants may slow mammalian aging while they avoid the complications of insulin resistance.

Aging leads to quantitative and qualitative changes in platelet (Plt) production, with increased risk for thrombosis and other adverse cardiovascular events. Recent reports showed that aging promotes the emergence of non-canonical (nc) megakaryocyte progenitors (MkPs) directly from hematopoietic stem cells (HSCs), leading to the production of hyperactive Plts. The higher engraftment potential of ncMkPs compared to both young and old canonical (c)MkPs, contrasts with the functional decline of old HSCs. Emerging reports suggest that mitochondrial function critically regulates lineage commitment and cellular functionality, but how mitochondrial activity affects aging megakaryopoiesis is unknown. Here, we demonstrate that aged MkPs sustain unique mitochondrial activity, characterized by higher mitochondrial membrane potential, higher ATP content, and lower ROS levels compared to their younger counterparts. This contrasts with the dysfunctional mitochondrial state observed in old HSCs, suggesting lineage-specific organelle adaptations upon aging. Notably, we observed that the elevated mitochondrial capacity in aged MkPs is driven selectively by the age-specific ncMkPs. Paradoxically, in vivo pharmacological enhancement of mitochondrial activity in old mice reduced in situ Plt production, but increased Plt reconstitution by transplanted HSCs. These discoveries link uniquely regulated mitochondrial capacity to the intrinsic properties of age-specific MkPs, raising the possibility of therapeutic targeting to prevent aging-induced megakaryopoiesis.

Aging is a complex biological process marked by progressive physiological decline and increased disease vulnerability. Single-cell RNA sequencing offers unprecedented resolution for studying aging, yet isolating aging-related signatures remains challenging because gene expression is primarily shaped by other factors such as cell type, tissue, and sex. We present ACE (Aging Cell Embeddings), an explainable deep generative framework that disentangles aging-related gene expression changes from background biological variation. ACE employs two latent representations: one capturing aging-related signatures and another representing non-aging-related variation in the data. Through explainable AI, ACE identifies key genes and pathways associated with aging amid dominant non-aging-related variations. Applied to large-scale mouse, fly, and human datasets, ACE uncovers aging signatures both within specific tissue-cell-type contexts and across all tissues and cell types, enabling accurate prediction of biological age. Moreover, ACE identifies aging genes conserved across species, highlighting its ability to reveal shared biological mechanisms of aging. Experimental RNAi knockdowns in C. elegans validate ACE\'s findings, confirming its ability to prioritize novel aging genes affecting lifespan. ACE reveals key pathways involved in proteostasis, immune regulation, and extracellular matrix remodeling, and identifies Uba52 through the cross-species model as an important aging gene, whose knockdown in C. elegans significantly shortens lifespan. By providing interpretable and generalizable aging embeddings, ACE establishes a foundation for cross-species single-cell aging studies and translational geroscience.

The exopolysaccharide SREP-1, purified from the fermentation broth of Stropharia rugosoannulata, exhibited antiaging potential. As aging significantly alters gut structure and function, protective effect of SREP-1 was investigated using a d-galactose-induced aging mouse model. SREP-1 administration reversed D-galactose-induced body weight loss and colon damage, as evidenced by improved histopathology. SREP-1 mitigated weight loss and colon damage, enhanced the activities of antioxidants (SOD, GSH-Px, and CAT), and reduced the level of MDA. It decreased proinflammatory cytokines (TNF-α, IL-1β, and IL-6) and elevated IL-10 in colon tissue, while boosting serum immunoglobulins (IgG and IgM). Crucially, these effects were abolished by antibiotic pretreatment, highlighting the role of gut microbiota in SREP-1 bioactivity. This role was further confirmed through fecal microbiota transplantation (FMT) and fecal supernatant transplantation (FST) experiments. Based on 16S rRNA sequencing, SREP-1 restored gut microbial diversity, increased beneficial genera (e.g., Faecalibacterium, Akkermansia, Lactobacillus, and Bacteroides), and decreased harmful bacteria (e.g., Escherichia-Shigella and Collinsella). Furthermore, short-chain fatty acids (SCFAs) levels were elevated in the SREP-1 group, which might regulate GPCRs/NF-κB/Nrf2 signaling pathways and exert biological activity. This study revealed the potential of SREP-1 to alleviate aging-related intestinal dysfunction and underscored the crucial role of gut microbiota in mediating these effects.

Abstract Background and Aims Obesity shortens life expectancy, yet its prognostic value in older adults remains unclear due to the obesity paradox and limitations of body mass index (BMI) in capturing visceral fat. We compared eight obesity indices and lifelong weight changes for mortality prediction and tested whether epigenetic age acceleration (EAA) mediates these associations in a US cohort. Methods In 2,222 NHANES (1999 to 2002) adults aged 50 years or order, we calculated BMI, waist circumference, waist to height ratio, weight adjusted waist index (WWI), body roundness index, relative fat mass, conicity index (CI), and 10 year/long term weight change. EAA was derived from five clocks (Horvath, Hannum, PhenoAge, GrimAge, GrimAge2). Cox regression, restricted cubic splines, and bootstrap mediation assessed hazard ratios (HRs), dose response curves, and indirect effects. Results WWI and CI outperformed other indices. Highest quartiles raised all cause mortality by 91% (HR 1.91, 95% CI 1.36 to 2.68) and 56% (HR 1.56, 95% CI 1.17 to 2.08), respectively. Each SD increase in WWI/CI was associated with higher GrimAge and GrimAge2 acceleration. Conversely, 10 year and long term weight gain reduced mortality risk. Additionally, EAA was lowest with stable or mildly increased weight. Mediation analysis confirmed that EAA significantly mediates the association of both WWI/CI with mortality risk, as well as the protective effect of weight stability. Conclusions Novel obesity indices (WWI, CI) are superior mortality predictors in older adults. Epigenetic ageing partly explains both the hazard of central adiposity and the survival benefit of weight homeostasis, supporting age-stratified obesity metrics and weight-stability targets. Keywords: Obesity, Biological aging, Epigenetic age, Apigenetic age acceleration, Death

Premature ovarian insufficiency (POI) is a complex reproductive disorder with a strong genetic component. The known POI causative genes currently account for only a small fraction of cases. In this study, we conducted whole-exome sequencing and identified a rare heterozygous missense variant in DNA helicase B (HELB) (c.349G>T, p.Asp117Tyr) in a Chinese family with POI and early menopause. To investigate the pathogenicity of this variant, a knockin mouse model carrying a heterozygous missense Helb variant (Helb+/D112Y) homologous to the human HELB c.349G>T was constructed. The Helb-mutated female mice exhibited reduced litter sizes and prolonged interlitter intervals compared with wild-type mice after reaching 10 months of age, leading to a shortened reproductive lifespan. Consistently, aged Helb+/D112Y females showed decreased ovarian weight and accelerated follicle depletion. Transcriptomic analysis of the ovaries from Helb-mutated mice revealed dysregulated expression of genes associated with impaired ovarian function and ovarian aging. Collectively, these findings in both humans and mice suggest that HELB is involved in maintaining ovarian function and regulating reproductive aging, highlighting the importance of HELB in female reproductive health.

The colonic epithelium is a key interface between the gut microbiota and the host. How microbiota-derived signals influence epithelial cell identity and function remains incompletely understood. Here, we used single-cell transcriptomics, antibiotic-mediated microbiota depletion, germ-free mice and colonization experiments in mice to uncover cell-type-specific responses to microbiota changes, highlighting changes in the cell composition and functional diversities in enterocytes. Our analysis demonstrates that the microbiota control the absorptive profile of the colon epithelial cells and reveals non-canonical inter-crypt goblet cells as microbiota-responsive constituents that combine absorptive and secretory features and whose abundance is regulated by the gut microbiota. We found that their number is suppressed through the short-chain fatty acid butyrate and its receptor GPR109A. Analysis in mouse and humans indicates that the expansion of this hybrid population increases with age and that this expansion is driven by microbiome changes. Our work reveals a previously unrecognized level of epithelial plasticity driven by microbial triggers and highlights butyrate, acting as a signaling molecule that shapes the colon micro-anatomy.

Stress granules are biomolecular condensates that form in response to environmental stress and disassemble once normal conditions are restored. However, when disassembly fails, stress granules can persist and solidify. While stress granule solidification has been well documented, the cellular mechanisms underlying the transition from reversible to persistent stress granules remain unclear. Persistent stress granules can seed the formation of pathological aggregates, such as TDP-43 in amyotrophic lateral sclerosis. Although amyloid-{beta} and tau aggregates are hallmarks of Alzheimer\'s disease, a subset of patients also develop TDP-43 deposits, suggesting a possible role for stress granule solidification in Alzheimer\'s disease progression. Despite theoretical models explaining why persistence and ensuing solidification occurs, strong in vivo evidence is lacking. Here we show that competition for limited chaperone resources drive stress granule persistence. In the presence of TDP-43 aggregates or yeast amyloid proteins called prions, stress granule disassembly is slowed or halted disassembly. Using yeast prions as a model, we show that the addition of chaperones, specifically the AAA+ ATPase molecular chaperone, Hsp104, resulted in resumption of stress granule disassembly. Our results demonstrate that the competition for shared resources, such as molecular chaperones, can limit stress granule disassembly. We suspect that the presence of pathological aggregates results in resource competition within the aging brain, contributing to the persistence of stress granules and their subsequent solidification and aggregation.