Aging Cell

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

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

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

Aging reduces skeletal muscle regenerative capacity, but how the aged environment impairs muscle stem cells (MuSCs) remains unclear. Skeletal muscle acts as a secretory organ, yet age-related changes in its secretome and impact on stem cells are poorly understood. We performed proteomic and lipidomic analyses of conditioned media from primary muscle cells of young (15-25 years) and aged (60-86 years) donors. We identified 127 age-dependent secreted proteins, revealing major remodeling. The lysosomal enzyme acid sphingomyelinase (ASM), which converts sphingomyelin into ceramide, was the most upregulated factor. Recombinant ASM reduced PAX7+ MuSCs in young cultures, showing extracellular ASM impairs stem cell maintenance. Lipidomics revealed disruption of the sphingomyelin-ceramide-S1P axis, with decreased sphingomyelin and S1P, a lipid promoting MuSC proliferation. Exogenous S1P restored the stem cell pool in aged cultures. These findings link secretome remodeling and sphingolipid metabolism to MuSC decline and identify ASM and S1P as targets

Aged skeletal muscle has decreased ability to rebound from physiological stressors such as disuse atrophy. We previously observed that older adults during recovery following muscle disuse were characterized by rapid skeletal muscle immune cell expansion, cellular senescence and collagen deposition, responses that were biased toward older women. Here we used single-nucleus RNA sequencing and complementary in vitro muscle primary cell experiments in young (YF; 22[plusmn]3y; n=8) and older females (OF; 66[plusmn]5y; n=9) to investigate age-mediated cellular function and intercellular communication during recovery from disuse atrophy. Compared with YF, OF exhibited a markedly greater transcriptional response at 7d-recovery (YF: 1,548 DEGs, OF: 7,999 DEGs), driven primarily by slow- (YF: 96 DEGs, OF: 984 DEGs) and fast-twitch myonuclei (YF: 194 DEGs, OF: 1,234 DEGs), satellite cells (YF: 548 DEGs, OF: 2,784 DEGs) and FAPs (YF: 326 DEGs, OF: 2,102 DEGs). Satellite cells from OF demonstrated collagen signatures including elevated THBS1 expression and enrichment of TGF-[beta] signaling. Concurrently, OF FAPs exhibited increased expression of fibroblast activation marker ADAMTS14. Furthermore, NicheNet analyses unmasked altered FAP-satellite cell communication in OF. Complementary In vitro experiments revealed that myogenic progenitor cells collected at 7d-recovery from OF (vs YF) donors displayed impaired myogenic differentiation and a cellular senescence-associated phenotype, while fibroblasts exhibited greater myofibroblast-like activation. Conditioned media derived from OF fibroblasts at 7d-recovery further increased cellular senescence and impaired myogenic potential (vs YF fibroblast conditioned media). Collectively, these findings suggest that recovery from disuse atrophy in older females is characterized by altered FAP-satellite cell communication and intrinsic function which may contribute to poor muscle remodeling.

Postmitotic neurons must preserve genome integrity for decades despite continuous oxidative, transcription-associated, and environmental DNA damage. Although recent studies have established ongoing repair-associated DNA synthesis in mature neurons, the polymerases that execute this synthesis remain incompletely defined. DNA polymerase kappa (POLK), a Y-family translesion synthesis polymerase, is highly expressed in neurons and undergoes an age-associated redistribution from the nucleus to the cytoplasm, suggesting that loss of nuclear POLK may compromise neuronal genome maintenance. Here, we investigated the consequences of POLK loss and augmentation in primary mouse cortical neurons and human induced pluripotent stem cell-derived forebrain neurons, including APOE e4/e4 backgrounds. Partial POLK depletion reduced neuronal arbor complexity, enlarged neuronal nuclei, increased LAMIN A/C and nuclear-envelope abnormalities, and induced a multidimensional senescence-like stress phenotype characterized by increased senescence-associated {beta}-galactosidase, p21, nuclear p38 MAPK, inflammatory signaling, lysosomal remodeling, and reduced mitochondrial-associated staining. POLK localized in proximity to EdU-labeled DNA in mature neurons, and POLK depletion reproducibly reduced EdU incorporation across independent human neuronal backgrounds and maturation stages. Exploratory nuclear POLK immunoprecipitation-mass spectrometry, together with proximity ligation assays, placed POLK near proteins involved in nucleotide excision repair, base-excision/single-strand break repair, DNA-end repair, checkpoint signaling, and specialized polymerase regulation, including PCNA-Ub and RAD18. POLK loss also produced Alzheimer disease-relevant cellular phenotypes. In wild-type neurons, POLK depletion increased 6E10 immunoreactivity and was accompanied by remodeling of APP/endosomal, lipid/cholesterol, and lysosomal pathways. In APOE e4/e4 neurons, POLK depletion increased cytoplasmic dsDNA and phospho-tau. Conversely, neuron-directed POLK augmentation increased EdU incorporation while reducing 53BP1 and {gamma}H2AX signals, p38 MAPK, cytoplasmic dsDNA, 6E10 immunoreactivity, and phospho-tau. Together, these findings identify POLK as a component of repair-associated DNA synthesis in mature neurons and support a model in which neuronal POLK availability contributes to genome maintenance, stress resilience, and vulnerability in aging and Alzheimer disease-relevant states.

Background Reduced muscle strength is associated with cognitive decline and Alzheimer's disease (AD), suggesting that skeletal-muscle aging and AD-related neurodegeneration may share biological mechanisms. Vascular dysfunction, immune activation, and extracellular-matrix remodeling have been implicated in both tissues, but the extent of shared cellular and molecular programs remains unclear. We investigated cross-tissue transcriptional programs in aging skeletal muscle and AD-related brain tissue and evaluated whether related signals are detectable in peripheral blood. Methods We analyzed independent, unpaired human transcriptomic datasets from skeletal muscle (23 donors), the SEA-AD middle temporal gyrus atlas (84 donors), and peripheral blood. Donor-aware models identified age-associated changes in muscle and transcriptomic changes across continuous pseudoprogression score (CPS) in brain. Cross-tissue comparisons focused on 30 brain donors within an early CPS window. Shared tissue-derived programs were assessed in peripheral blood mononuclear cells and independently tested in frailty bulk-blood and Alzheimer's Disease Neuroimaging Initiative (ADNI) whole-blood datasets. CellOracle simulations were used to prioritize candidate transcriptional regulators. Results Aging muscle showed increased inflammatory, extracellular-matrix, and stromal communication programs. During early AD-related brain progression, vascular and immune populations showed increasing inflammatory and matrix-associated activity together with shifts in intercellular communication. Cross-tissue analysis identified six concordantly enriched pathways comprising 109 leading-edge genes in endothelial populations and four pathways comprising 51 genes in myeloid populations. Related peripheral-blood signatures varied across cohorts and cell types. However, in independent frailty and ADNI mild cognitive impairment and AD datasets, 23 of 30 predefined tissue-derived pathway-subset tests showed significant positive enrichment after false-discovery-rate correction, whereas individual gene-level bulk-blood associations did not survive correction. CellOracle analyses prioritized ETS2 and BHLHE40 as exploratory endothelial regulators whose simulated perturbation consistently reduced selected shared program scores across tissues. Conclusions Aging skeletal muscle and AD-related brain tissue exhibit convergent endothelial and myeloid inflammatory programs, with related pathway-level signals detectable in peripheral blood. These cross-tissue programs and candidate endothelial regulators provide testable hypotheses for mechanisms linking systemic aging, muscle dysfunction, and AD-related neurodegeneration.

The ovary is one of the first organs to age, with declines in oocyte quantity and quality leading to infertility and loss of endocrine function. Why the ovary ages earlier than somatic tissues has remained enigmatic but may relate to its highly dynamic physiology and substantial demand for cellular debris clearance. Each ovulation forms a corpus luteum (CL), a transient endocrine structure which supports pregnancy but regresses in its absence. Because CLs have a short functional lifespan but prolonged structural regression, they represent a substantial source of ovarian debris. We hypothesized that post-ovulatory debris clearance becomes impaired with age and contributes to ovarian fibroinflammation. Using a CL-labeling system, we demonstrated that CLs from reproductively old mice show dysregulated regression, resulting in an accumulation of persistent CLs (pCLs) which appeared concurrently with ovarian multinucleated giant cells (MNGCs). Laser capture microdissection, RNA sequencing, and histological evaluation of CLs, pCLs, and MNGCs demonstrated that pCLs were focal hotspots of proinflammatory and debris-associated signatures enriched in lipids, extracellular matrix, and immune cells. Although pCLs retained luteal features, they were transcriptionally more similar to MNGCs than CLs. Consistent with this, an ex vivo CL model acquired MNGC-associated molecular features during extended culture, suggesting that pCLs may represent sites of MNGC formation. Culture of isolated follicles or ovarian stromal organoids with factors from MNGC-enriched explants induced compartment-specific fibroinflammatory responses. These findings provide novel mechanistic insight into ovarian aging, whereby post-ovulatory debris clearance is compromised with age, leading to pCL accumulation, MNGC formation, and a fibroinflammatory milieu.

The progressive collapse of protein homeostasis is a defining feature of aging, yet upstream events deteriorating protein synthesis remain poorly defined. Zinc is an essential micronutrient and structural cofactor, but its role in the aging ribosomal proteome is poorly understood. Here, using Caenorhabditis elegans, we show that the whole-body zinc-to-sulfur ratio declines by ~90% between day 1 and day 13 of adulthood. Supplementing aged animals with a low dose of ZnCl2 (10 M) restored organismal zinc levels and improved healthspan, thermotolerance, and oxidative stress resistance, whereas higher doses were toxic. Quantitative proteomics revealed that structural constituents of the ribosome were the most enriched functional category altered by zinc, accompanied by robust induction of metallothionein MTL-1. Zinc-supplemented animals exhibited increased protein synthesis and a transient increase in ribosomal proteins, while 45S pre-rRNA levels remained unaffected, indicating that zinc acts on ribosome structure rather than biogenesis. Zinc supplementation coordinately reversed the age-associated decline of antioxidant, chaperone, proteasome, and energy-metabolism factors. Furthermore, zinc conferred protection in two proteotoxicity models, suppressing polyglutamine aggregation and delaying amyloid-beta-induced paralysis. Our findings establish that zinc preserves translational proteostasis, identifying late-life zinc supplementation as a translatable micronutrient intervention against age-related proteinopathies.

The ovary ages earlier than most other organs, but the molecular mechanisms that drive this decline remain unclear. To gain more insight into this process, we profiled ovaries from young and reproductively aged mice after synchronized ovulation and found that aging was marked by the accumulation of luteal cells with increased steroidogenic, antigen presentation and inflammatory gene expression. DNA methylation was globally preserved in aged ovaries but showed focal age-associated changes at gene regulatory regions. Protein profiling identified an increase in checkpoint kinase 2 (CHK2), a DNA damage response protein encoded by the CHEK2 gene associated with the timing of natural menopause in humans. CHK2 and DNA damage markers were increased in aged mice and human ovarian somatic cells. Transient CHK2 inhibition in aged mice increased the proportion of mature oocytes and blastocyst formation and reversed inflammatory signatures in granulosa cells. These findings identify defective luteal resolution and inflammation as features of ovarian aging and suggest that CHK2 induces a reversible age-associated inflammatory signature. Our results show that reproductive decline may remain pharmacologically modifiable during ovarian aging via regulation of the inflammatory response.

Menopause timing links reproductive lifespan with later life health, motivating investigation of its molecular and hematological correlates. We combined Generation Scotland analyses of women sampled at or after reported menopause (n = 1,444) and initially menstruating women followed for GP ascertained menopause onset (n = 1,725; 251 events) with bidirectional and multivariable Mendelian randomization. Higher age adjusted GrimAge V1, GrimAge V2 and DunedinPACE corresponded to 0.34 to 0.40 years earlier menopause per SD in the retrospective cohort at nominal P < 0.05. Prospective associations were nonsignificant, and cohort and primary bidirectional aging-related genetic associations did not survive multiple-testing correction. Genetically predicted later menopause was associated with higher neutrophil percentage and count and lower lymphocyte percentage in women; these associations and female vs. male contrasts survived correction. CRP conditional on menopause timing was associated with higher GrimAge and PhenoAge acceleration and shorter leukocyte telomere length after correction. None of 36 estimated inflammatory indirect effects reached P < 0.05. These findings highlight blood-cell composition as a prominent correlate of reproductive timing and identify selected methylation-aging signatures for further study. Together, they position reproductive hematological relationships as a specific avenue for understanding the connection between menopause and systemic aging.

Despite recent evidence of the ability of systemic and organ-specific proteomic aging clocks to predict a large range of age-related diseases, their utility in cancer research remains largely underexplored. In this study, we evaluated the predictive ability of systemic and organ-specific proteomic aging clocks for (i) all-cause mortality, (ii) cancer-related mortality, and (iii) cancer incidence in a sample of Finnish twins (N = 401, mean age at baseline 62.3 years) with Olink proteomic data. Participants were followed for a mean of 10.6 years (SD +- 1.6), with estimates from four systemic and 18 organ-specific proteomic aging clocks calculated at baseline. Cox proportional hazards regression models adjusted for sex and age at baseline identified 15 proteomic aging clocks as significant predictors of all-cause mortality (Ncases = 28) after multiple testing correction (FDR < 0.05), with 11 remaining significant after lifestyle adjustment (Ncases = 27). For several clocks, effect sizes were large, with hazard ratios (HR) approximately doubling per one standard deviation (SD) increase in clock estimates. In predicting cancer-related deaths among participants without a prior cancer diagnosis at baseline (Ncases = 9), only the Immune clock showed a significant positive association after multiple testing correction in basic (HR = 2.94, 95% CI: 1.88-4.59) and lifestyle-adjusted models (HR = 3.31, 95% CI: 1.78-6.17). No associations with cancer incidence (Ncases = 34 basic, Ncases = 31 adjusted) survived multiple testing correction, although several nominal associations were observed. In conclusion, our findings suggest that proteomic aging clocks are strong predictors of all-cause and cancer-specific mortality, independent of lifestyle factors. Proteomic aging clocks may further serve as valuable tools for stratifying cancers by mortality risk.

Apigenin is an abundant, bioactive phytochemical with reported therapeutic potential and neuroprotective effects in a variety of age-related disease models. However, the extent to which apigenin may promote healthspan and protect against neurodegeneration-associated proteotoxicity has not been thoroughly investigated, and the biological processes/mechanisms that underlie its protective effects remain unclear. To determine if apigenin increases healthspan, we performed lifespan assays in conjunction with measures of aging-relevant physiological function in wild-type C. elegans. We found that chronic exposure to apigenin extended median lifespan and improved multiple readouts of healthspan, including pharyngeal pumping, locomotor activity, and age-related macromolecular damage accumulation. Additional analyses of transgenic reporter strains and transcriptomic profiling (RNA-seq) indicated that apigenin primarily modulated redox-sensitive stress signaling and pathways associated with cellular homeostasis in aging animals. Finally, in transgenic C. elegans strains expressing the pathological Alzheimer's disease-associated proteins amyloid-beta or tau, we found that apigenin had similar beneficial effects on lifespan, healthspan, and proteotoxicity-associated functional impairments. Together, our results support apigenin as a potential healthspan-promoting intervention that acts in part through reductions in oxidative stress-associated signaling, with beneficial effects that extend to models of Alzheimer's disease-associated proteotoxicity.

Purpose: The neural retina and retinal pigment epithelium/choroid (RPE/Cho) are metabolically coupled. Metabolic dysfunction of the RPE/Cho contributes to photoreceptor death in age-related macular degeneration (AMD). This study aimed to determine how aging, a major risk factor for AMD, alters the proteome and metabolic pathways in the retina and RPE/Cho. Methods: We performed quantitative proteomics on neural retina and RPE/Cho from young (8-week) and old (73-week) C57BL/6J mice. The differentially expressed proteins between old and young, as well as between the retina and RPE/Cho, were visualized using volcano plots and heatmaps, and functional analyses were assessed by Gene Ontology enrichment tools. Results: Aging altered the expression of 85 retinal proteins and 272 RPE/Cho, with 16 shared between tissues. In the aged retina, proteins associated with NADP(H) metabolism, neurodegeneration, and immunity were mostly upregulated, while proteins in lipid metabolism, transcription, and epigenetic regulation decreased. In the aged RPE/Cho, all 21 significantly altered lysosomal enzymes and transport proteins increased, together with complement components, and photoreceptor outer segment proteins. These changes accompanied increases in proteins associated with lipid metabolism and protection against lipid peroxidation, while several glutathione metabolism enzymes decreased. Seven shared proteins involved in lipid and NADP(H) metabolism, changed in opposite directions between retina and RPE/Cho. Comparison of the retinal and RPE/Cho proteomes identified 3073 differentially abundant proteins, of which 2452 maintained tissue-specific differences across both age groups, while approximately 17% showed age-dependent shifts in tissue enrichment. These shifts involved proteins associated with metabolism, extracellular matrix, visual function, lysosomal pathways, and innate immunity. Within the metabolic proteome, several glycolytic and fatty acid oxidation proteins showed greater relative enrichment in RPE/Cho with age, whereas glucose transporters and mitochondrial complexes shifted toward the retina. Conclusions: Overall, these findings show that aging differentially remodels the retina and RPE/Cho proteome, accompanied by altered metabolic specialization between the two tissues.

Frailty reflects declining physiological reserve across multiple organ systems with aging, yet the underlying biological mechanisms contributing to frailty remain poorly understood. We tested whether somatic mutations in the blood were associated with incident frailty and faster progression in 730,088 participants from UK Biobank, All of Us, BioVU and the Womens Health Initiative. We found that clonal hematopoiesis of indeterminate potential (CHIP) and autosomal mosaic chromosomal alterations showed strong associations with frailty, whereas mosaic loss of chromosome X or Y did not. Findings were consistent across survey-based, directly measured and clinically assessed frailty, as well as healthspan phenotypes. A Tet2 mouse model demonstrated multisystem frailty-like functional decline and T-cell remodeling. In humans, T-cell activation-related proteins directly mediated the association between clonal hematopoiesis and frailty. Collectively, these findings support a model in which clonal hematopoiesis accelerates biological aging through immunosenescence.

Maintenance of neuronal function during aging requires metabolic adaptation, yet how metabolite-sensitive chromatin regulators contribute to this process remains unclear. YEATS-domain proteins, including ENL and AF9, recognize histone acylation marks and are positioned at the interface between cellular metabolism and transcriptional regulation. We previously showed that pan-neuronal suppression of dENL/AF9, the single Drosophila orthologue of mammalian ENL and AF9, extends lifespan, preserves healthspan, and enhances oxidative-stress resistance. Here, we used multi-omics and biochemical analyses to define the molecular state associated with neuronal dENL/AF9 suppression. Transcriptomic profiling revealed a markedly stronger response in aged than young male fly heads, with prominent enrichment of fatty-acid degradation and several intermediary metabolic pathways in the aged dataset. Guided by this age-related transcriptional response, we focused subsequent profiling on aged heads, where independent molecular layers converged on a distinct metabolic and energetic signature. Lipidomics identified reduced abundance of multiple triglyceride-related and fatty acid derivatives, while metabolomics revealed changes in central-carbon/TCA-, nicotinamide-, and purine-associated features. Proteomics implicated mitochondrial and ATP-associated processes, accompanied by increased ATP abundance and a higher NAD/NADH ratio. Matched lipidome-metabolome integration further identified citrate as a cross-omics feature inversely associated with altered triglyceride and ceramide species, linking central-carbon and lipid-associated components of the molecular signature. Together, these findings identify a stronger transcriptional response to neuronal dENL/AF9 suppression in aged flies and a distinct metabolic and energetic molecular signature in aged fly heads, providing candidate molecular correlates of the previously established longevity phenotype and a framework for studies of neuronal aging biology.

Fibro-adipogenic progenitors (FAPs) have emerged as central regulators of the skeletal muscle homeostasis and the muscle microenvironment. However, the role of FAPs in the context of exercise-induced muscle hypertrophy remains largely unexplored. Here, we utilized six weeks of blood flow restricted resistance exercise (BFRRE) to study cellular adaptations within the muscle microenvironment accompanying muscle hypertrophy in healthy older individuals. Using flow cytometry, we characterized global changes of key cell populations within the skeletal muscle microenvironment, including FAPs, muscle stem cells (MuSCs), and immune cells. BFRRE induced significant enlargement of both FAPs and MuSCs, consistent with cellular adaptation to exercise. Notably, exercise shifted the FAP pool toward an increased predominance of the CD90high FAP phenotype, without altering total FAP abundance. In addition to matrix and collagen-related genes, transcriptional analysis of genes associated with secretory proteins revealed enrichment of promyogenic factors in CD90high versus CD90low FAPs. Conditioned media experiments of freshly isolated FAPs demonstrated that CD90high FAPs promote myotube growth in vitro compared to CD90low counterparts, suggesting that this phenotypic shift may facilitate muscle hypertrophy. In parallel, BFRRE increased the proportion of pro-inflammatory (CD11c+) macrophages within the skeletal muscle niche, highlighting a dynamic immune response during adaptation. Finally, we show identified possible link between pro-inflammatory macrophages and FAPs, as TNF markedly reduced the proliferation of human primary FAPs ex vivo, suggesting that macrophage-derived signals may attenuate excessive FAP expansion during tissue remodelling. Together, these findings provide new insight into how the remodelling of the cellular niche may support muscle hypertrophy in response to exercise. The coordinated expansion and phenotypic remodeling of FAP and immune cell populations may represent an important mechanism through which exercise supports hypertrophy in older individuals.

Bone loss and metabolic dysregulation often coexist in older adults, yet the relationship between age-related changes in bone cell metabolism and bone-forming activity remains unclear. By modeling both conditions in aged mice and using in vivo stable-isotope tracing, we demonstrated that age-related decline in bone formation was coupled with an intrinsic impairment of glycolysis within bone tissue. Impaired glycolysis was associated with reduced protein levels of key glycolysis enzymes, and transcriptomics analyses revealed compensatory upregulation of glycolysis genes in aged bone. Metabolic intervention through long-term caloric restriction prevented age-related trabecular bone loss. Furthermore, osteoblast-specific genetic enhancement of glycolysis, via overexpression of HIF1 or the rate-limiting enzyme PFKFB3, significantly improved osteoblast function and increased bone mass in aged mice. Together, the study identifies glycolytic decline as a cell-autonomous driver of osteoblast deficiency and provides proof of principle that reactivating glycolysis can promote bone accrual in aging.

Individuals with Down syndrome (DS) exhibit accelerated biological aging and unique patterns in disease prevalence. However, empirical characterizations of relative risk and age at onset of disease in this population are not common. Here we aimed to quantify the difference in risk and timing of age-related conditions between individuals with DS when compared to typically developing (TD) matched controls. We used semiparametric Cox proportional hazards models and Restricted Mean Event-Free Age (RMEA) to estimate differences in risk and approximate average age at onset of cataracts, cognitive decline, death, menopause, and osteoporosis. Individuals with DS were at higher risk of all age-related conditions or events and experienced these events at younger ages, excluding menopause. We observed a 24.5-fold higher risk of cognitive decline in individuals with DS (p<0.001), and between a 2- and 4-fold higher risk of the other age-related events or conditions (p<0.01). Cognitive decline and death occurred more than 14 years earlier in individuals with DS and were more likely to co-occur (p<0.001) compared to in TD individuals. These findings have important implications for tailored screening and prevention efforts in aging individuals with DS, as this population experiences a distinct cadence of age-related events.

Aging is associated with impaired skin wound healing, but the molecular mechanisms underlying this decline remain incompletely understood. In particular, how aging affects the temporal regulation of mechanosensitive signaling during tissue repair is poorly understood. In this study, we investigated age-associated changes in cutaneous wound healing, with a focus on Yes-associated protein (YAP)-associated mechanosensitive responses, and examined whether ICE mice, an inducible model of epigenetic aging, reproduce age-associated impairment in wound repair. Splinted full-thickness excisional wounds were generated in young and naturally aged mice, and wound closure, gene expression, and active YAP were evaluated over time. Aged mice exhibited delayed wound closure, particularly during the mid-to-late phases of repair. Expression of the fibrosis-related genes Tgfb1, Col1a1, and Col3a1, and the YAP-associated genes Ctgf, Cyr61, and Arhgap18 did not differ significantly between young and aged wounds at the examined time points. In contrast, Ankrd1 was selectively elevated in aged wounds at postoperative day 14. Active YAP immunofluorescence showed age-associated differences in staining patterns during wound healing, indicating altered regulation of mechanosensitive signaling with aging. Furthermore, ICE mice exhibited delayed wound closure compared with Cre control mice, reproducing a major functional feature observed in naturally aged mice. These findings suggest that age-associated impairment of wound healing is characterized not by uniform activation or suppression of YAP-related signaling, but by altered temporal regulation of mechanosensitive responses together with selective Ankrd1 elevation. ICE mice could provide a useful experimental model for investigating age-associated defects in cutaneous wound healing.