Longevity Papers

Immunoglobulin G (IgG) N-glycans have been identified as associated with aging; however, previous studies predominantly quantified changes based on the relative percentages of each glycan within the total glycan pool, neglecting the absolute concentration changes of individual glycans. Additionally, relative quantification can limit practical applications, as these often require absolute concentration measurements for consistent and interpretable biomarker values. In this study, we introduce a novel strategy for discovering aging-associated IgG glycans and establishing a prediction model based on their absolute concentration alteration. We employed a glycome quantification technology to identify the alteration in IgG glycan amount in natural aging and anti-aging (caloric restriction) models, discovering aging-related glycans. The glycomics analysis revealed key features: downregulation of bisected glycan GP3 (F(6)A2B) and upregulation of digalactosylated glycan GP8 (F(6)A2G2). These glycan changes showed significant fold changes from an early stage. Using external standards of these two glycans, we subsequently measured the absolute concentrations of them, allowing us to establish a predictive model, abGlycoAge, for biological aging. The abGlycoAge index suggested a younger state under caloric restriction, with an average age reduction of 3.9-14 weeks. Additionally, we performed RNA sequencing on splenic B cells of mice, suggesting Derl3, Smarcb1, Ankrd55, Tbkbp1 and Slc38a10 could contribute to the alteration of GP3 and GP8 in aging. This analysis enhances our understanding of glycan alterations, accounts for individual variability, and aids in designing effective anti-aging strategies. These findings highlight the crucial roles of the GP3 and GP8 as potential biomarkers for aging and health.

Impaired mitochondrial bioenergetics in macrophages can drive hyperinflammatory cytokine responses, but whether this may also be caused by inherited mtDNA mutations is unknown. Here, we address this question using a multi-omic approach that integrates super-resolution imaging and metabolic analyses to profile macrophages from a mouse model of mitochondrial disease arising from a heteroplasmic mutation (m.5019A>G) in the mitochondrial tRNA for alanine. These m.5019A>G macrophages exhibit defects in respiratory chain complexes and oxidative phosphorylation (OxPhos) due to decreased intra-mitochondrial translation. To adapt to this metabolic stress, mitochondrial fusion, reductive glutamine metabolism, and aerobic glycolysis are all increased. Upon inflammatory activation, type I interferon (IFN-I) release is enhanced, while the production of pro-inflammatory cytokines and oxylipins are restrained in m.5019A>G macrophages. Finally, an in vivo endotoxemia model using m.5019A>G mice reveal elevated IFN-I levels and sickness behaviour. In conclusion, our study identifies an unexpected imbalance in innate immune signalling in response to a pathogenic mtDNA mutation, with important implications for the progression of pathology in patients with mtDNA diseases.

Age-related diseases are often linked to chronic inflammation. Senescent cells secrete inflammatory cytokines, chemokines and matrix metalloproteinases, collectively referred to as the senescence-associated secretory phenotype (SASP). The current study discovered that aging leads to the accumulation of senescent tendon stem/progenitor cells (TSPCs) in tendon tissue, resulting in the development of a SASP. Conditioned medium from aged TSPCs induced cellular inflammation in young TSPCs. In addition, we found that Canopy homolog 2 (CNPY2) expression is reduced during tendon aging. CNPY2 deficiency causes TSPCs senescence and SASP. Our findings showed that the NF-κB signaling pathway is activated in CNPY2 knockdown TSPCs, pharmacological inhibition of NF-κB signaling pathway with BMS-345541 attenuated SASP of senescent TSPCs, which indicated that CNPY2 regulates TSPCs SASP might through NF-κB signaling pathway. Our findings suggested that CNPY2 plays an important role in TSPCs senescence and SASP, CNPY2 could be a promising target for age-related tendon disorders.

Maintaining homeostasis is essential for continued health, and the progressive decay of homeostatic processes is a hallmark of ageing. Daily environmental rhythms threaten homeostasis, and circadian clocks have evolved to execute physiological processes in a manner that anticipates, and thus mitigates, their effects on the organism. Clocks are active in almost all cell types; their rhythmicity and functional output are determined by a combination of tissue-intrinsic and systemic inputs. Numerous inputs for a specific tissue are produced by the activity of circadian clocks of other tissues or cell types, generating a form of crosstalk known as clock communication. In mammals, the central clock in the hypothalamus integrates signals from external light-dark cycles to align peripheral clocks elsewhere in the body. This regulation is complemented by a tissue-specific milieu of external, systemic and niche inputs that modulate and cooperate with the cellular circadian clock machinery of a tissue to tailor its functional output. These mechanisms of clock communication decay during ageing, and growing evidence suggests that this decline might drive ageing-related morbidities. Dietary, behavioural and pharmacological interventions may offer the possibility to overcome these changes and in turn improve healthspan.

Aging of the brain vasculature plays a key role in the development of neurovascular and neurodegenerative diseases, thereby contributing to cognitive impairment. Among other factors, DNA damage strongly promotes cellular aging, however, the role of genomic instability in brain endothelial cells (EC) and its potential effect on brain homeostasis is still largely unclear. We here investigated how endothelial aging impacts blood-brain barrier (BBB) function by using excision repair cross complementation group 1 (ERCC1)-deficient human brain ECs and an EC-specific Ercc1 knock out (EC-KO) mouse model. In vitro, ERCC1-deficient brain ECs displayed increased senescence-associated secretory phenotype expression, reduced BBB integrity, and higher sprouting capacities due to an underlying dysregulation of the Dll4-Notch pathway. In line, EC-KO mice showed more P21

Angiogenesis plays a pivotal role in ischemic cardiovascular disease, accompanied by epigenetic regulation during this process. Sirtuin 6 (SIRT6) has been implicated in the regulation of DNA repair, transcription and aging, with its deacetylase activity fully studied. However, the role of SIRT6 demyristoylase activity remains less clear, with even less attention given to its myristoylated substrates. In this study, we report that endothelial specific SIRT6 knockout attenuated angiogenesis in mice, while SIRT6 was observed to promote migration and tube formation in endothelial cell. Notably, we further determined that SIRT6 affects the intracellular VEGFA and global myristoylation level under hypoxia. Moreover, ALK14 (myristic acids analogue) treatment and SIRT6 knockdown results in a significant decrease in VEGFA secretion under hypoxia, implying the involvement of SIRT6 demyristoylase activity in angiogenesis. Mechanistically, CLICK IT assay verified that VEGFA is a myristoylated substrate of SIRT6. Further, overexpression of SIRT6 mutants (R65A, G60A and H133Y) results in profound differences in VEGFA secretion, indicating that SIRT6 promotes VEGFA secretion through demyristoylation but not deacetylation. Finally, overexpression of SIRT6 rescued the diminishment of endothelial migration, tube formation and sprouting caused by ALK14 treatment. Overall, our study demonstrates that SIRT6 regulates angiogenesis by demyristoylating VEGFA and increasing VEGFA secretion. Therefore, modulation of SIRT6 demyristoylase activity may represent a therapeutic strategy for ischemic cardiovascular disease.

Obesity and metabolic syndrome are major public health concerns linked to cognitive decline with aging. Prior work from our lab has demonstrated that short-term high fat diet (HFD) rapidly impairs memory function via a neuroinflammatory mechanism. However, the degree to which these rapid inflammatory changes are unique to the brain is unknown. Moreover, deviations in gut microbiome composition have been associated with obesity and cognitive impairment, but how diet and aging interact to impact the gut microbiome, or how rapidly these changes occur, is less clear. Thus, our study investigated the impact of HFD after two distinct consumption durations: 3 months (to model diet-induced obesity) or 3 days (to detect the rapid changes occurring with HFD) on memory function, anxiety-like behavior, central and peripheral inflammation, and gut microbiome profile in young and aged rats.

During aging, microglia, the resident macrophages of the brain, exhibit altered phenotypes and contribute to age-related neuroinflammation. While numerous hallmarks of age-related microglia have been elucidated, the progression from homeostasis to dysfunction during the aging process remains unresolved. To bridge this gap in knowledge, we undertook complementary cellular and molecular analyses of microglia in the mouse hippocampus across the adult lifespan and in the experimental aging model of heterochronic parabiosis. Single-cell RNA-Seq and pseudotime analysis revealed age-related transcriptional heterogeneity in hippocampal microglia and identified intermediate states of microglial aging that also emerge following heterochronic parabiosis. We tested the functionality of intermediate stress response states via TGFB1 and translational states using pharmacological approaches in vitro to reveal their modulation of the progression to an activated state. Furthermore, we utilized single-cell RNA-Seq in conjunction with in vivo adult microglia-specific Tgfb1 conditional genetic knockout mouse models, to demonstrate that microglia advancement through intermediate aging states drives transcriptional inflammatory activation and hippocampal-dependent cognitive decline.

Aging is a complex biological process influenced by various factors, including genetic and environmental influences. In this study, we present BayesAge 2.0, an upgraded version of our maximum likelihood algorithm designed for predicting transcriptomic age (tAge) from RNA-seq data. Building on the original BayesAge framework, which was developed for epigenetic age prediction, BayesAge 2.0 integrates a Poisson distribution to model count-based gene expression data and employs LOWESS smoothing to capture nonlinear gene-age relationships. BayesAge 2.0 provides significant improvements over traditional linear models, such as Elastic Net regression. Specifically, it addresses issues of age bias in predictions, with minimal age-associated bias observed in residuals. Its computational efficiency further distinguishes it from traditional models, as reference construction and cross-validation are completed more quickly compared to Elastic Net regression, which requires extensive hyperparameter tuning. Overall, BayesAge 2.0 represents a step forward in tAge prediction, offering a robust, accurate, and efficient tool for aging research and biomarker development.

Quantifying the mechanical response of the biological milieu (such as the cell's interior) and complex fluids (such as biomolecular condensates) would enable a better understanding of cellular differentiation and aging and accelerate drug discovery. Here we present time-shared optical tweezer microrheology to determine the frequency- and age-dependent viscoelastic properties of biological materials. Our approach involves splitting a single laser beam into two near-instantaneous time-shared optical traps to carry out simultaneous force and displacement measurements and quantify the mechanical properties ranging from millipascals to kilopascals across five decades of frequency. To create a practical and robust nanorheometer, we leverage both numerical and analytical models to analyse typical deviations from the ideal behaviour and offer solutions to account for these discrepancies. We demonstrate the versatility of the technique by measuring the liquid-solid phase transitions of MEC-2 stomatin and CPEB4 biomolecular condensates, and quantify the complex viscoelastic properties of intracellular compartments of zebrafish progenitor cells. In Caenorhabditis elegans, we uncover how mutations in the nuclear envelope proteins LMN-1 lamin A, EMR-1 emerin and LEM-2 LEMD2, which cause premature aging disorders in humans, soften the cytosol of intestinal cells during organismal age. We demonstrate that time-shared optical tweezer microrheology offers the rapid phenotyping of material properties inside cells and protein blends, which can be used for biomedical and drug-screening applications.

Ovarian function declines significantly as females enter middle-age, but the mechanisms underlying this decline remain unclear. Here, we utilize whole-organ imaging to observe a notable decrease in ovarian blood vessel (oBV) density and angiogenesis intensity of middle-aged mice. This leads to a diminished blood supply to the ovaries, resulting in inadequate development and maturation of ovarian follicles. Utilizing genetic-modified mouse models, we demonstrate that granulosa cell secreted VEGFA governs ovarian angiogenesis, but the physiological decline in oBV is not attributed to VEGFA insufficiency. Instead, through single-cell sequencing, we identify the aging of the ovarian vascular endothelium as the primary factor contributing to oBV decline. Consequently, the administration of salidroside, a natural compound that is functional to reverse oBV aging and promote ovarian angiogenesis, significantly enhances ovarian blood supply and improve fertility in older females. Our findings highlight that enhancing oBV function is a promising strategy to boost fertility in females.

Chronic low-grade inflammation observed in older adults, termed inflammaging, is a common feature underlying a multitude of aging-associated maladies including a decline in hematopoietic activity. However, whether suppression of inflammaging can preserve hematopoietic health span remains unclear, in part because of a lack of tools to measure inflammaging within hematopoietic stem cells (HSCs). Here, we identify thrombospondin-1 (Thbs1) as an essential regulator of inflammaging within HSCs. We describe a transcriptomics-based approach for measuring inflammaging within stem cells and demonstrate that deletion of

Aging is a complex and universal process marked by gradual functional declines at the cellular and tissue levels, often leading to a range of aging-related diseases such as diabetes, cardiovascular diseases, and cancer. Delaying the aging process can help prevent, slow down, and alleviate the severity of these various conditions, enhancing overall health and well-being. Alpha-glucosidase inhibitors (AGIs) are a class of widely used antidiabetic drugs that inhibit alpha-glucosidase in the small intestinal mucosa, delaying carbohydrate absorption and reducing postprandial hyperglycemia. Beyond their roles in diabetes treatment, AGIs have shown potential in extending lifespan and effectively treating aging-related diseases by modulating oxidative stress, gut microbiota, inflammatory responses, and nutrient-sensing pathways. This review summarizes recent advancements in the application of AGIs for preventing and treating aging and aging-related diseases, with a focus on their mechanisms and roles in these processes.

Methylnissolin-3-O-β-d-glucopyranoside (MNG) and methylnissolin (MN) are pterocarpan derivatives that are found in plants, such as Astragalus membranaceus. There are limited existing studies on the potential health benefits of MNG, and currently there is no evidence to suggest that MNG has any impact on skin-aging. Tumor necrosis factor-alpha (TNF-α) plays a significant role in skin aging by promoting chronic inflammation, damaging skin cells, and impairing the skin's natural repair mechanisms. Targeting TNF-α or its downstream signaling pathways may be a promising strategy for preventing or reversing skin-aging. We tested the effect of MNG and MN on skin-aging by inducing cell inflammation and oxidative stress with TNF-α in HDFs. MNG and MN significantly reduced the TNF-α-induced secretion of matrix metalloproteinase-1 (MMP-1). However, MNG has more beneficial compound for oral administration than MN in pharmacokinetics analysis. The mechanism underlying the anti-skin-aging effect of MNG is related to the suppression of TNF-α-induced reactive oxygen species (ROS) generation and mitogen-activated protein kinase (MAPKs) phosphorylation. Our results suggest that MNG is a potential candidate for preventing skin-aging induced by TNF-α.

Demographic aging and extended working lives have prompted interest in the physiological changes that occur with age, particularly in the lumbar spine. Age-related declines in muscle quality and intervertebral disc alterations may reduce muscular endurance, strength, and postural stability, potentially increasing the risk of musculoskeletal injuries in older workers. As experienced workers play an important role in addressing labor shortages, understanding the impact of age-related physiological changes on the biomechanical properties of the lumbar spine is key to ensure safe and sustainable employment for aging individuals. This study aimed to compare the impact of daily work-related physical efforts on lumbar muscular endurance and fatigue, spine tissue properties, and postural stability between older and younger workers. A total of 40 participants, 20 in Group 1 (young workers: ≤50 years; mean age: 28.89 ± 7.23) and 20 in Group 2 (older workers: >50 years; mean age: 59.40 ± 5.29) were recruited. Measurements taken at the beginning and end of the workday included lumbar muscle endurance, maximal voluntary contraction, disc height and postural stability. Age groups were compared using repeated measures ANOVA across the two measurement times. No significant interaction between age and time of day was observed, indicating that, for similar workload, both age groups experienced similar changes. Despite age-related effects on maximal force production and postural stability, incorporating weight as a covariate revealed that these differences were partially explained by the weight discrepancy between older and younger workers. The study suggests that age may not be the primary determinant of the impact of a workday on older workers.

Aging is a complex and multifaceted process involving many epigenetic alterations. One key area of interest in aging research is the role of histone modifications, which can dynamically regulate gene expression. Here, we conducted a pan-tissue analysis of the dynamics of seven key histone modifications during human aging. Our histone-specific age prediction models showed surprisingly accurate performance, proving resilient to experimental and artificial noise. Simulation experiments for comparison with DNA methylation age predictors revealed competitive performance. Moreover, gene set enrichment analysis uncovered several critical developmental pathways for age prediction. Different from DNA methylation age predictors, genes known to be involved in aging biology are among the most important ones for the models. Last, we developed a pan-tissue pan-histone age predictor, suggesting that age-related epigenetic information is degenerated across the epigenome. This research highlights the power of histone marks as input for creating robust age predictors and opens avenues for understanding the role of epigenetic changes during aging.

ASXL1 is one of the three most frequently mutated genes in age-related clonal hematopoiesis (CH), with the others being DNMT3A and TET2. CH can progress to myeloid malignancies including chronic monomyelocytic leukemia (CMML), and is also strongly associated with inflammatory cardiovascular disease and all-cause mortality in humans. DNMT3A and TET2 regulate DNA methylation and demethylation pathways respectively, and DNMT3A and TET2 loss-of-function mutations in CH reduce DNA methylation in heterochromatin, allowing de-repression of silenced elements in heterochromatin. In contrast, the mechanisms that connect mutant ASXL1 and CH are not yet fully understood. CH/CMML-associated ASXL1 mutations encode C-terminally truncated proteins that enhance the deubiquitinase activity of the ASXL-BAP1 ''PR-DUB '' deubiquitinase complex, which removes mono-ubiquitin from H2AK119Ub. Here we show that ASXL1 mutant proteins interact with the EHMT1-EHMT2 methyltransferase complex, which generates H3K9me1 and me2, the latter a repressive modification in constitutive heterochromatin. Compared to cells from age-matched wildtype mice, we found that expanded myeloid cells from old (>18-month-old) Asxl1tm/+ mice, a heterozygous knock-in mouse model of CH, display genome-wide decreases of H3K9me2, H3K9me3 and H2AK119Ub as well as an associated increase in expression of transposable elements (TEs) and satellite repeats. Increased TE expression was also observed in monocytes from ASXL1-mutant CMML patients compared to monocytes from healthy control individuals. Our data suggest that mutant ASXL1 proteins compromise the integrity of both constitutive and facultative heterochromatin in an age-dependent manner, by reducing the levels of H3K9me2/3 and H2AK119Ub respectively. The resulting increase in TE expression can alter the expression of nearby genes and promote the expression of inflammation-associated and interferon-inducible genes (ISGs).

Chronological age is a cornerstone of medical decision-making but is limited because individuals age at different rates. We recently released an open-source deep learning model to assess biological age from chest radiograph images (CXR-Age), which predicts incident all-cause and cardiovascular mortality better than chronological age. Here, we compare CXR-Age to two established epigenetic aging clocks (First generation- Horvath Age; Second generation- DNAm PhenoAge), to test which is more strongly associated with measures of cardiopulmonary disease. Our cohort consisted of 2,097 participants from the Project Baseline Health Study (PBHS), a prospective cohort study of individuals from four US sites enriched for cardiovascular and cardiometabolic disease risk factors. We found that CXR-Age was most strongly associated with the presence of coronary calcium, cardiovascular risk factors, worsening pulmonary function, increased frailty, and abundance in plasma of two proteins implicated in neuroinflammation and aging. Associations with second generation epigenetic clocks were weaker for pulmonary function and for all outcomes in younger adults. No associations were found with first generation clocks. These results suggest that opportunistic screening using CXR-Age may help identify high risk individuals who could benefit from directed screening and prevention.

T-cell receptor (TCR) diversity is crucial for adaptive immunity, yet baseline characterizations in pediatric populations remain sparse. We sequenced the TCRβ chain of 325 healthy Chinese children aged 0-18, categorized into six age groups. We also analyzed cellular composition and TCRβ associations using flow cytometry in 81 of these samples. Our results indicate a decrease in TCRβ diversity with age, characterized by an increase in high-frequency clonotypes and notable changes in CDR3 length and V(D)J gene usage. These changes are influenced by early life vaccinations and antigen exposures. Additionally, we found a significant association between reduced TCRβ diversity and a decrease in CD4

Frailty is a common geriatric syndrome associated with poor clinical outcomes. Effectiveness of lifestyle intervention programmes among frail older people has been examined earlier, but effects of interventions on prevention of frailty have been rarely studied. The aim of this study was to investigate to what extent the multidomain lifestyle intervention in the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) affected changes in frailty status among older men and women at risk of cognitive disorders.

Endothelial dysfunction, characterized by a decline in endothelial physiological functions, is a significant aspect of cardiovascular aging, contributing notably to arterial stiffness, atherosclerosis, and hypertension. Transient receptor potential channel V4 (TRPV4), a key member of Ca

Introduction The increasing aging population raises significant concerns about the ability of individuals to age healthily, avoiding chronic diseases and maintaining cognitive and physical functions. However, the pathways through which SDOH factors are associated with healthy aging remain unclear. Methods This retrospective cohort study used the registered tier data from the All of Us Research Program (AoURP) registered tier dataset v7. Eligible study participants are those aged 50 and older who have responded to any of the SDOH survey questions with available EHR data. Three different algorithms were trained (logistic regression [LR], multi-layer perceptron [MLP], and extreme gradient boosting [XGBoost]). The outcome is healthy aging, which is measured by a composite score of the status for 1) comorbidities, 2) cognitive conditions, and 3) mobility function. We evaluate the model performance by area under the receiver operating characteristic curve (AUROC) and assess the fairness of best-performed model through predictive parity. Feature importance is analyzed using SHapley Additive exPlanations (SHAP) values. Results: Our study included 99,935 participants aged 50 and above, and the mean (SD) age was 74 (9.3), with 55,294 (55.3%) females, 67,457 (67.5%) Whites, 11,109 (11.1%) Hispanic ethnicity, and 44,109 (44.1%) are classified as healthy aging. Most of the individuals lived in their own house (64%), were married (51%), obtained college or advanced degrees (74%), and had Medicare (56.2%). The best predictive model was XGBoost with random oversampler, with a performance of AUROC [95% CI]: 0.793 [0.788-0.796], F1 score: 0.697 [0.692-0.701], recall: 0.739 [0.732-0.748], precision: 0.659 [0.655-0.663], and accuracy: 0.716 [0.712-0.720], and the XGBoost model achieved predictive parity by similar positive and negative predictive values across race and sex groups (0.86-1.06). In feature importance analysis, health insurance type is ranked as the most predictive feature, followed by employment status, substance use, and health insurance coverage (yes/no). Conclusion In this cohort study, XGBoost model accurately predicted individuals achieving healthy aging, outperforming LR and MLP. Our findings underscore the significant role of health insurance in contributing to healthy aging.

Cellular senescence plays a significant role in tissue aging. Senescent cells, which resist apoptosis while remaining metabolically active, generate endogenous DNA-damaging agents, primarily reactive oxygen species. Efficient DNA repair is therefore crucial in these cells, especially when they undergo senescence escape, resuming DNA replication and cellular proliferation. To investigate whether senescent cell transcriptomes reflect adequate DNA repair capacity, we conducted a comprehensive meta-analysis of 60 transcriptomic datasets comparing senescent to proliferating cells. Our analysis revealed a striking downregulation of genes encoding essential components across DNA repair pathways in senescent cells. This includes pathways active in different cell cycle phases such as nucleotide excision repair, base excision repair, nonhomologous end joining and homologous recombination repair of double-strand breaks, mismatch repair and interstrand crosslink repair. The downregulation observed suggests a significant accumulation of DNA lesions. Experimental monitoring of DNA repair readouts in cells that underwent radiation-induced senescence supported this conclusion. This phenomenon was consistent across various senescence triggers and was also observed in primary cell lines from aging individuals. These findings highlight the potential of senescent cells as 'ticking bombs' in aging-related diseases and tumors recurring following therapy-induced senescence.

Porphyra haitanensis proteins (PHP) are natural proteins with various nutritional and biological values. This study was to analyze the composition, stability, and antioxidant activity of PHP before and after simulation gastrointestinal digestion (SGD). Caenorhabditis elegans was used as the model to investigate the functional activity and potential mechanisms of action of the PHP digestion products (PHPDP). The results showed that PHP contained 16 amino acids and exhibited high thermal stability (up to 80 °C), but dimerization or fragmentation occurred in environments with pH 3 and pH 11. After digestion, PHP released 212 bioactive peptides, which significantly enhanced its antioxidant activity and improved the resistance of C. elegans to heat, oxidative, and ultraviolet stress. Furthermore, PHPDP improved oxidative stress in C. elegans and extended its lifespan by increasing antioxidant enzyme activity and reducing malondialdehyde, lipofuscin, and reactive oxygen species levels. The mechanism of action of PHPDP likely involved regulating the insulin signaling pathway through daf-2/daf-16 and modulating the expression of oxidative stress regulators skn-1 and sod-3, thereby enhancing the organism's stress resistance and extending lifespan. This study demonstrated that P. haitanensis could serve as a reliable protein source in daily life and provided a reference for its development and application as a functional food ingredient.

Age-dependent sensory impairment, memory loss, and cognitive decline are generally attributed to neuron loss, synaptic dysfunction, and decreased neuronal activities over time. Concurrently, increased neuronal activity is reported in humans and other organisms during aging. However, it is unclear whether neuronal hyperactivity is the cause of cognitive impairment or a compensatory mechanism of circuit dysfunction. The roundworm

Sarcopenia and reduced muscle quality index have garnered special attention due to their prevalence among older individuals and the adverse effects they generate. Early detection of these geriatric pathologies holds significant potential, enabling the implementation of interventions that may slow or reverse their progression, thereby improving the individual's overall health and quality of life. In this context, artificial intelligence opens up new opportunities to identify the key identifying factors of these pathologies, thus facilitating earlier intervention and personalized treatment approaches.

A wave of studies has recently emphasized the influence of sex chromosomes on both lifespan and actuarial senescence patterns across vertebrates and invertebrates. Basically, the heterogametic sex (XY males in XX/XY systems or ZW females in ZW/ZZ systems) typically displays a lower lifespan and a steeper rate of actuarial senescence than the homogametic sex. However, whether these effects extend to the senescence patterns of other phenotypic traits or physiological functions is yet to be determined. Here, we investigated whether sex chromosomes modulate reproductive senescence using females from the African pygmy mouse (

The mechanisms underlying the impact of probiotic supplementation on health remain largely elusive. While previous studies primarily focus on the discovery of novel bioactive bacteria and alterations in the microbiome environment to explain potential probiotic effects, our research delves into the role of living Lactiplantibacillus (formerly known as Lactobacillus) and their conditioned media, highlighting that only the former, not dead bacteria, enhance the healthspan of Caenorhabditis elegans (C. elegans). To elucidate the underlying mechanisms, we conduct transcriptomic profiling through RNA-seq analysis in C. elegans exposed to GTB1, a strain of Lactiplantibacillus plantarum or 3-phenyllactic acid (PLA), mimicking the presence of key candidate metabolites of GTB1 and evaluating healthspan. Our findings reveal that PLA treatment significantly extends the healthspan of C. elegans by promoting energy metabolism and stress resilience in a SKN-1/ATFS-1-dependent manner. Moreover, PLA-mediated longevity is associated with a novel age-related parameter, the Healthy Aging Index (HAI), introduced in this study, which comprises healthspan-related factors such as motility, oxygen consumption rate (OCR), and ATP levels. Extending the relevance of our work to humans, we observe an inverse correlation between blood PLA levels and physical performance in patients with sarcopenia, when compared to age-matched non-sarcopenic controls. Our investigation thus sheds light on the pivotal role of the metabolite PLA in probiotics-mediated enhancement of organismal healthspan, and also hints at its potential involvement in age-associated sarcopenia. These findings warrant further investigation to delineate PLA's role in mitigating age-related declines in healthspan and resilience to external stressors.

Neuronal aging and neurodegenerative diseases are accompanied by proteostasis collapse, while cellular factors that trigger it are not identified. Impaired mitochondrial transport in the axon is another feature of aging and neurodegenerative diseases. Using Drosophila, we found that genetic depletion of axonal mitochondria causes dysregulation of protein degradation. Axons with mitochondrial depletion showed abnormal protein accumulation and autophagic defects. Lowering neuronal ATP levels by blocking glycolysis did not reduce autophagy, suggesting that autophagic defects are associated with mitochondrial distribution. We found that eIF2beta was increased by the depletion of axonal mitochondria via proteome analysis. Phosphorylation of eIF2alpha, another subunit of eIF2, was lowered, and global translation was suppressed. Neuronal overexpression of eIF2beta phenocopied the autophagic defects and neuronal dysfunctions, and lowering eIF2beta expression rescued those perturbations caused by depletion of axonal mitochondria. These results indicate the mitochondria-eIF2beta axis maintains proteostasis in the axon, of which disruption may underly the onset and progression of age-related neurodegenerative diseases.

Offspring of older breeders frequently show reduced longevity, which has been linked to shorter offspring telomere length. It is currently unknown whether such telomere reduction persists beyond a single generation, as would be the case if germline transmission is involved. In a within-grandmother, multi-generational study using zebra finches, we show that the shorter telomeres observed in F1 offspring of older mothers are still present in the F2 generation even when the breeding age of their F1 mothers is young. The effect was substantial: 43% shorter telomeres in grandoffspring from the 'grandmother old at breeding' line compared with those from the 'grandmother young at breeding' line. Shorter telomeres at fledging in this species are associated with a reduction in lifespan. Our data demonstrate the need to look beyond a single generation to explain inter-individual variation in ageing rates and thereby variation in optimal allocation of age-specific reproductive effort.

Telomere attrition is a hallmark of biological aging, contributing to cellular replicative senescence. However, few studies have examined the determinants of telomere attrition in vivo in humans. Mitochondrial Health Index (MHI), a composite marker integrating mitochondrial energy-transformation capacity and content, may be one important mediator of telomere attrition, as it could impact telomerase activity, a direct regulator of telomere maintenance. In this observational longitudinal study, we examined in peripheral blood mononuclear cells (PBMCs), whether MHI predicted changes in telomerase activity over a 9-month period, thus impacting telomere maintenance over this same period of time. We secondarily examined the role of chronic stress, by comparing these relationships in mothers of children with an autism spectrum disorder (caregivers) vs. mothers of a neurotypical child (controls). Here we show that both chronic stress exposure and lower MHI independently predicted decreases in telomerase activity over the subsequent 9 months. Finally, changes in telomere length were directly related with changes in telomerase activity, and indirectly with MHI and chronic stress, as revealed by a path analysis. These results highlight the potential role of chronic stress and MHI as drivers of telomere attrition in human PBMCs, through an impairment of both energy-transformation capacity and telomerase production.

Hypoxia triggers blood-brain barrier disruption and a strong microglial activation response around leaky cerebral blood vessels. These events are greatly amplified in aged mice which is translationally relevant because aged patients are far more likely to suffer hypoxic events from heart or lung disease, and because of the pathogenic role of blood-brain barrier breakdown in vascular dementia. Importantly, it is currently unclear if disrupted cerebral blood vessels spontaneously repair and if they do, whether surrounding microglia deactivates. In this study, we addressed these questions by exposing aged (20 months old) mice to chronic mild hypoxia (8% O

Age-related macular degeneration (AMD) is the leading cause of vision loss among the elderly individuals. Retinal pigment epithelium (RPE) ferroptosis is a significant pathogenetic component in AMD. This study aims to elucidate the role and mechanisms of fatty acid desaturase 1 (FADS1) in ferroptosis as well as AMD progression.

Impaired muscle mitochondrial oxidative capacity is associated with future cognitive impairment, and higher levels of PET and blood biomarkers of Alzheimer's disease and neurodegeneration. Here, we examine its associations with up to over a decade-long changes in brain atrophy and microstructure. Higher in vivo skeletal muscle oxidative capacity via MR spectroscopy (post-exercise recovery rate, k

Sarcopenia is an age-related disease that is characterized by a decline in muscle mass and function with significant epidemiological and clinical implications. In recent years, gut microbiota has gained attention as an important regulatory factor in human health. To the best of our knowledge, this is the first study to introduce the definition and epidemiological background of sarcopenia and analyze the potential impact of the gut microbiota on muscle metabolism and growth, including aspects such as gut microbiota metabolites, muscle protein synthesis and energy metabolism. Additionally, this article summarizes the current research progress in gut microbiota interventions for the treatment of sarcopenia, such as probiotics, prebiotics and fecal microbiota transplantation and discusses future research directions and potential therapeutic strategies.

The mammalian heart contains cardiac stem cells throughout life, but it has not been possible to harness or stimulate these cells to repair damaged myocardium in vivo. Assuming physiological relevance of these cells, which have evolved and have been maintained throughout mammalian evolution, we hypothesize that cardiac stem cells may contribute to cardiomyogenesis in an unorthodox manner. Since the intermediate filament protein desmin and the matricellular Secreted Protein Acidic and Rich in Cysteine (SPARC) promote cardiomyogenic differentiation during embryogenesis in a cell-autonomous and paracrine manner, respectively, we focus on their genes and employ mouse embryonic and cardiac stem cell lines as in vitro models to ask whether desmin and SPARC cooperatively influence cardiomyogenesis in cardiac stem and progenitor cells. We show that desmin also promotes cardiomyogenesis in a non-cell autonomous manner by increasing the expression and secretion of SPARC in differentiating embryonic stem cells. SPARC is also secreted by cardiac stem cells where it promotes cardiomyogenesis in an autocrine and concentration-dependent manner by upregulating the expression of myocardial transcription factors and its elicitor desmin. Desmin and SPARC interact genetically, forming a positive feedback loop and secreted autocrine and paracrine SPARC negatively affects sparc mRNA expression. Paracrine SPARC rescues cardiomyogenic desmin-haploinsufficiency in cardiac stem cells in a glycosylation-dependent manner, increases desmin expression, the phosphorylation of Smad2 and induces the expression of gata4, nkx2.5 and mef2C. Demonstration that desmin-induced autocrine secretion of SPARC in cardiac stem cells promotes cardiomyogenesis raises the possibility that a physiological function of cardiac stem cells in the adult and aging heart may be the gland-like secretion of factors such as SPARC that modulate age-related and adverse environmental influences and thereby contribute to cardiac homeostasis throughout life.

How aging affects axon regeneration and synaptic repair in the brain is poorly understood. To study age-related changes in neural circuits, we developed a model of axonal injury in the aged (> 2 years) mouse somatosensory cortex. By directly tracking fluorescently labelled injured axons by multiphoton imaging, we find that while axon degeneration in the aged brain is comparable to the young adult brain, axon regeneration is impaired. We further examine changes in the most common type of cortical synapses, En Passant Boutons (EPBs), and observe a transient and significant increase in the number and size of boutons 6 hours post-lesion. Using a computational model of a recurrent neural network, we examined the functional consequences of these synaptic increases on memory, comparing results to models of the young adult brain. The results suggest that increased synaptic dynamics might enable partial recovery from injury via synaptic re-wiring in the aged brain.

Anemarrhena asphodeloides Bge. (AAB), a traditional medicinal herb, has a long history of delaying the aging process. Yet, the anti-aging effects of its polysaccharides have not been thoroughly investigated. This study marks the first exploration of the anti-aging activity of Anemarrhena asphodeloides Bge. polysaccharides (AABP). The MW of AABP-1a was determined to be 210.062 kDa, with a composition consisting predominantly of glucose and mannose in a molar ratio of approximately 4:1. The backbone of AABP-1a was mainly composed of →4)-2Ac-β-Man(1→ and →4)-β-Glc(1→ and a small amount of branched →4,6)-β-Glc(1→ and →3,4)-β-Glc(1→, the branching part was composed of →6)-β-Glc(1→ and t-α-Glc(1→. AABP-1a has antioxidant capacity and can improve cell cycle arrest mediated by senescence markers such as p53, p21, p16 and SASP, and reduce the accumulation of damaged DNA. In addition, it could reduce the activity of SA-β-Gal in zebrafish, prolong the lifespan of C. elegans and reduce the expression of lipofuscin. This study found a glucomannan and demonstrated its anti-aging activity in various aging models. These results provide a theoretical basis for further study of the anti-aging effect of AAB.

Fasting-mimicking diets (FMDs) have shown to result in various health benefits, including body weight reduction, body fat reduction, decreased blood pressure and longevity promoting effects through enhanced ketogenesis and reduced glycolysis. The direct impact of FMDs on metabolite fluctuations, however, remains elusive. Here, we explore the effects of FMDs on the human salivary metabolic profiles and weight in a single-arm case study. Specifically, we present a bio-energetic framework to estimate fat loss as a component of the sustained weight loss, the effects on metabolite quantities involved in energetic reprogramming and the effects on the abundance of metabolites originating from the gut microbiome. These findings highlight the importance of metabolic health tracking to further our understanding of the effects of fasting, personalized nutrition and effective preventive health measures.

Precise control of stem cell activity is critical to maintain homeostasis and regenerative capacity of adult tissues and limit proliferative syndromes. Hence, stem cell-specific complex regulatory networks exist to exquisitely maintain gene expression and adapt it to tissue demand, controlling self-renewal, fate commitment and differentiation of developing and adults cell lineages. One of the essential and conserved regulatory components that fine-tune gene expression are microRNAs, which post-transcriptionally regulate stability and translation of messengers. microRNAs have been identified as critical stem cell regulators across stem cell populations and organisms. Here, we report the profiling of microRNAs expressed in stem cells and their immediate daughter cells in the Drosophila adult intestine. Our analysis identifies over 60 miRs that can be reliably detected in these sorted progenitor cells; a few of these have been reported to control fly intestinal stem cells, but most have yet to be investigated in the adult intestinal lineage. To validate the relevance of our unbiased analysis, we chose to characterize the phenotypes associated with genetic manipulations of two of these microRNAs, miR-31a and miR-34, which are conserved in other organisms, but whose function has not been investigated in the Drosophila midgut. We found that miR-31a acts as anti-proliferation factor and is important for the re-entry of ISC into quiescence after tissue damage. Additionally, we demonstrate that miR-34 is essential for ISC proliferation, but its over-expression also prevents proliferation, highlighting the complexity of miR-mediated control of stem cell function. Altogether, our work establishes a new critical resource to investigate the detailed mechanisms that control stem cell proliferation and intestinal differentiation under homeostatic conditions, in response to tissue damage, or during epithelial transformation and aging