Longevity Papers

SIRT1, a sirtuin family member, has been extensively documented to be closely linked to aging and aging-related disease. Cellular senescence is a state of irreversible cell cycle arrest that functions as a key driver of aging. During cellular senescence, LINE-1 (L1) retrotransposable elements become transcriptionally activated and stimulate a type-I interferon (IFN-I) response. L1 activity has been strongly linked to aging and a variety of age-related disorders. However, whether SIRT1 influences cellular senescence through the transposable element L1 remains unknown. In this study, we discovered that SIRT1 significantly suppresses L1 retrotransposition. Under quiescent conditions, SIRT1 exhibits increased enrichment at the L1 5'-UTR region. This recruitment enhances its interaction with the heterochromatin-regulatory factors Lamin B1 and KAP1, subsequently elevating H3K9me3 levels. This repressive chromatin mark inhibits L1 transcription, thereby maintaining genomic stability and delaying cellular senescence. Consistent with these observations, SIRT1-deficient cell lines exhibited a marked reduction of the interaction of Lamin B1 and KAP1 and a reduced presence of these factors at the L1 5'-UTR. Consequently, the elevated L1 transcription resulting from SIRT1 deficiency activated the cGAS-STING pathway and ultimately triggered cellular senescence, an effect that was rescued by treatment with 3TC (a nucleoside reverse transcriptase inhibitor). In summary, our findings demonstrate that SIRT1 suppresses L1 retrotransposition by recruiting heterochromatin factors, thereby delaying cellular senescence and providing new insights with implications for delaying aging and mitigating age-related pathologies.

Ovarian aging precedes decline in many organs, but its mechanisms remain unclear. Here we show that aging oocytes accumulate cytoplasmic mitochondrial DNA (mtDNA) through increased mtDNA leakage, activating the cyclic GMP-AMP synthase (cGAS) pathway to produce cGAMP and trigger stimulator of interferon genes (STING) signaling. Notably, oocyte-derived cGAMP can pass through gap junctions to surrounding granulosa cells (GCs), activating STING signaling in GCs as well. To model age-associated mitochondrial dysfunction, we generated oocyte-specific Tfam-knockout mice, which recapitulated mtDNA leakage, STING pathway activation in both oocytes and GCs, inflammation and accelerated ovarian dysfunction. We also used Opa1 knockdown and Pink1 deletion oocytes as complementary mitochondrial stress models and observed mtDNA leakage and cGAS-STING activation in both settings. Notably, oocyte-specific Cgas deletion in Tfam mutants or pharmacological STING inhibition with H-151 ameliorated ovarian dysfunction. These findings establish oocyte mtDNA leakage as a causal driver of ovarian aging and nominate cGAS-STING signaling as a therapeutic target.

Dietary protein restriction (PR) is a well-recognized nutritional intervention that enhances metabolic health and extends lifespan. However, the mechanisms behind this phenomenon are not well understood. Here, using genetic loss-of-function models for fibroblast growth factor 21 (Fgf21) and its obligate co-receptor β-Klotho (Klb), we demonstrate that FGF21-KLB signalling in adipocytes is indispensable for the anti-senescence effects of PR. Specifically, adipocyte FGF21 signalling preserves mitochondrial integrity, maintains an anti-inflammatory milieu and sustains nicotinamide adenine dinucleotide (NAD

Aging is associated with immune dysregulation in the brain and is the greatest risk factor for many neurodegenerative diseases. Rejuvenation interventions can mediate beneficial effects. Microglia are major contributors to neurodegenerative disease progression; however, the molecular changes underlying brain aging and rejuvenation remain poorly understood at the single-cell level. We identified and benchmarked several reproducible microglial states and a core set of genes that drive microglial activation in the mouse brain. We investigated microglial heterogeneity and examined the impact of aging and parabiosis-mediated exposure to young and old blood on microglial subpopulations across four brain regions: the cerebellum, cortex, hippocampus, and striatum. We revealed region-specific differences in microglial composition and age-related changes. The cerebellum consistently emerged as the most responsive region, whereas the striatum showed minimal responsiveness to parabiosis interventions. These findings highlight regional vulnerability and inform microglia-targeted strategies to modulate brain aging.

The stepwise movement of oxygen from the atmosphere to the mitochondria, the "oxygen cascade", is one of the most tightly regulated systems in physiology. Despite decades of mechanistic study, it has remained quite unexplored in Geroscience. This oversight should be reconsidered. In young organisms, hypoxic stress (whether environmental or tissue-specific) activates a complex adaptive response to preserve energetic stability via restraining anabolic pathways, optimizing mitochondrial performance, and reinforcing cellular quality control systems. With advancing age, angiostatic signaling increases, endothelial metabolism becomes dysregulated, and overall alveolar ventilation and pulmonary gas exchange (ventilation-perfusion matching and diffusion capacity) become less efficient. These changes promote microvascular rarefaction and low-grade but persistent mismatches between oxygen delivery and demand at the tissue level, ultimately destabilizing cellular function. In this review, we propose that the gradual erosion of oxygen homeostasis is not simply a byproduct of aging, but also a driver of molecular damage and functional decline. We examine the aging oxygen cascade through the framework of resilience biology, focusing on mechanisms such as mitochondrial electron leaks, oxidative stress amplification, iron dyshomeostasis, ferroptosis, and epigenetic remodeling. We also discuss interventions that alter oxygen availability, such as intermittent hypoxia, hyperbaric oxygen therapy, and hypoxic-hyperoxic training. These approaches demonstrate adaptive potential, but they also highlight the narrow margin between beneficial stress and injury. We propose "Oxygenaging" as a unifying framework in which aging associates with the progressive loss of equilibrium across the oxygen cascade, linking systemic oxygen transport to mitochondrial function, genomic stability, and cellular resilience.

The global prevalence of aging and age-related diseases has increased markedly in recent decades due to extended life expectancy and a growing aging population, posing substantial medical and social burdens. Multiple strategies, including metabolic modulation (e.g., physical exercise, calorie restriction, and calorie restriction mimetics), targeting inflammaging, senotherapy, parabiosis, stem cell-based therapies, and epigenetic rejuvenation, have shown promise in slowing aging and extending lifespan in preclinical models, with some demonstrating efficacy in clinical trials. This review summarizes the current status of leading anti-aging interventions, their clinical progress, and the underlying mechanisms, which include enhancing autophagy, clearing senescent cells and supporting mitochondrial function to reduce chronic inflammation. We propose that metabolic modulation, inflammaging control, and senotherapy constitute three interconnected pillars of contemporary anti-aging strategies.

Genotoxic stress induced by cancer therapies is increasingly recognized as a driver of accelerated aging in long-term cancer survivors, yet the mechanisms responsible for the emergence of age-related dysfunction months to years after treatment remain poorly understood. Here, we use sublethal whole-body irradiation as a model of systemic genotoxic stress to test whether senescent cells contribute to the progression of post-therapy age-related dysfunction and whether the benefits of senescent cell clearance depend on the timing of intervention. Using the INK-ATTAC mouse model, we selectively eliminated p16

Skeletal muscle is the main motor organ and plays a vital role in regulating systemic metabolism and aging. Exercise interventions can address many metabolic and degenerative diseases associated with aging, though alternative strategies may be needed when exercise is contraindicated, inaccessible or insufficient. Here we developed subcutaneous transplantation of differentiated autologous myocytes (myografts). Myografts exhibited mature, vascularized structures that self-contract continuously in mice. Myografts improve whole-body muscle mass and function, and metabolic and regenerative outcomes in aging and obese mouse models. In addition, myografts provide a stable source of virally transduced therapeutic proteins, such as parathyroid hormone and growth hormone, which may counteract bone or muscle loss without observed side effects. This approach opens a path for the application of cell and gene therapy in the treatment of diseases of aging.

Aging-associated inflammation is a driver of multiple age-associated diseases. Cyclic GMP-AMP synthase (cGAS) contributes to inflammaging by responding to endogenously-derived cytoplasmic DNA in aged cells. Although cGAS-knockout (KO) mice are viable, their aging has not been characterized. Unexpectedly, we found that cGAS KO mice exhibit an accelerated-aging phenotype, with induction of inflammation in multiple organs. cGAS KO mice display shortened median lifespan and increased frailty relative to wild-type mice. They show increased transcription of long interspersed nuclear element 1 (LINE1) retrotransposons, decreased DNA methylation on LINE1 elements and high levels of cytoplasmic LINE1 complementary DNA, which triggers inflammation, and this phenotype is recapitulated by cGAS knockdown in vitro. Furthermore, cells from cGAS KO mice show a smoothed H3K9me3 chromatin landscape and increased chromatin accessibility. In summary, our results show that cGAS functions to maintain heterochromatin organization in the nucleus, independent of its cytoplasmic role as a DNA sensor or its catalytic activity, with implications for geroprotective strategies targeting this pathway.

The gut microbiome profoundly influences host aging, yet the specific microbes and mechanisms governing divergent aging trajectories remain elusive. In this study, we delineated enterotype-specific gut microbial remodeling during aging and developed a microbiome-based aging clock (MicroAge) to track biological aging trajectories. We identified Bifidobacterium pseudocatenulatum (B. pseudocatenulatum) as a candidate geroprotective species consistently depleted during aging across both sexes and multiple Chinese cohorts. In naturally aged mice, oral B. pseudocatenulatum monotherapy rescued intestinal homeostasis, mitigated multiorgan inflammaging, enhanced cognitive-motor performance and extended healthspan. Mechanistically, we characterized 5-aminovaleric acid betaine (5-AVAB) as a key B. pseudocatenulatum-derived metabolite whose levels decline physiologically in aging humans. 5-AVAB supplementation partially recapitulated a broad spectrum of the systemic benefits observed with B. pseudocatenulatum treatment, including improved cognitive and motor function and suppressed multiorgan inflammaging. Our findings identify the B. pseudocatenulatum-5-AVAB axis as a promising target for microbiome-based interventions to promote healthy aging.

The accumulation of mitochondrial DNA (mtDNA) mutations is a primary driver of mitochondrial dysfunction, which is intrinsically linked to aging and various pathologies. POLG, the catalytic subunit of DNA polymerase gamma, is essential for mtDNA replication; notably, a deficiency in its proofreading function precipitates the accumulation of mtDNA mutations. In this study, by combining prime editing with somatic cell nuclear transfer technology, we successfully generated a mitochondrial mutator pig model expressing proofreading-deficient POLG. These pigs exhibited elevated somatic mtDNA mutation loads and recapitulated key premature aging phenotypes, including weight loss, rough hair coat, anemia, structural alterations in the skin and testicular interstitium, increased apoptosis, and the up-regulation of senescence-associated markers, culminating in shortened life span. Given the physiological and metabolic similarities between pigs and humans, this mitochondrial mutator pig model represents an ideal preclinical tool for dissecting the mechanistic role of mtDNA mutations in aging and age-related pathologies and for accelerating the translation of therapeutic strategies.

Reductive stress refers to a pathological shift toward a more reduced state in one or more defined redox couples, including NAD+/NADH, NADP+/NADPH, and GSSG/GSH, within specific cellular or subcellular compartments. Low-molecular-weight (LMW) thiols, including cysteine, cysteamine, glutathione, homocysteine, and hydrogen sulfide, contribute to cellular redox buffering, thiol-disulfide exchange, and redox-dependent metabolic regulation. Under chronic activation of antioxidant enzymatic systems, expansion of the reduced thiol pool may shift redox homeostasis toward a hyperreduced state, suppress physiological ROS-dependent signaling, and impair protein thiol-disulfide regulation. This review examines the cellular and molecular mechanisms of reductive stress within the neurovascular unit, the functional complex comprising microcapillary endothelial cells, pericytes, astrocytes, and neurons that maintains blood-brain barrier integrity and metabolic coupling. A reductive imbalance disrupts physiological redox signaling, impairs mitochondrial function, induces endoplasmic reticulum stress and the unfolded protein response (UPR), dysregulates ion channels and calcium homeostasis, promotes DNA damage, and activates cellular senescence programs and inflammasomes. Critically, reductive stress is not isolated but forms an integrated pathological network with oxidative, nitrosative, and glycation stresses, creating a self-sustaining cycle of mitochondrial dysfunction, macromolecular damage, and chronic neuroinflammation. Particular attention is given to compartment-specific redox regulation by mitochondrial glutathione and the peroxiredoxin/thioredoxin system, the dual role of ROS as physiological second messengers and mediators of secondary oxidative injury, and the links between hyperreduction, cellular senescence, AGE/RAGE signaling, and BBB dysfunction. We emphasize that reliable identification of reductive stress requires the simultaneous, compartment-resolved assessment of several redox couples and their functional consequences. This review also summarizes experimental approaches for modeling and detecting reductive stress and discusses emerging therapeutic strategies, including xenotopic enzymes, genetically encoded metabolic tools, and NAD+ modulation, aimed at restoring redox homeostasis and slowing neurodegeneration and aging.

Age is the primary risk factor for neurodegenerative diseases, which are characterized by cell-type-specific vulnerability. Yet brain-aging mechanisms remain unclear given the complex, interacting age-associated pathways across diverse neural cell types. Here, we dissect cell type- cell state-specific aging gene regulatory programs and their contribution to cellular vulnerability by leveraging epigenomics, AI methodology, and natural lifespan diversity across placental mammals. Applying the TACIT method, we associated lifespans of 240 placental mammals to the predicted open chromatin levels of over 3 million orthologous loci across 18 cortical cell types. We identified thousands of lifespan-associated open chromatin regions, enriched near genes associated with hallmarks of aging, which stratified greatly by cell type. For example, regions near mitochondrial genes showed differential selective pressure in long-lived species in energetically-demanding layer V ET neurons, while regions near inflammatory response genes were under selective pressure in glial populations. We next asked whether regions linked to vulnerable or resilient neurons in the human brain were under differential selective pressure in longer lived species. Using an adaptive representation learning approach, we decompose intrinsic aging programs from systemic effects in the prefrontal cortex and define an aging signature predictive of cell-type-specific vulnerability. In Alzheimer's disease, this intrinsic aging signature more strongly predicts vulnerability than systemic effects. Active regions in vulnerable neurons showed lower predicted activity in species with longer lifespans, suggesting selective pressure to down-regulate the vulnerability-associated networks. Overall, our findings argue against a single master regulator of aging, instead implicating different hallmarks across different cell types.

Homozygous pathogenic variants in Ig-like domain of LMNA cause severe segmental progeroid syndromes. Unlike typical HGPS, it remains elusive how these pathogenic variants cause segmental progeroid syndromes. We here reported that affected individuals with LMNAR527C/R527C pathogenic variant developed an atypical segmental progeroid syndrome characterized by autoimmune features. Mesenchymal stem cells (MSCs) derived from these affected individuals exhibited significant inflammation and cellular senescence. In mice, LmnaR527C/R527C pathogenic variant triggered chronic interferon signaling, exacerbated aging-related pathologies, and even induced thymic lymphomas following ionizing radiation. In addition, this pathogenic variant increased susceptibility to inflammation induced by a high-fat diet or LCMV infection. R527C pathogenic variant disrupted the interaction between Lamin A and DNA-binding proteins, causing abnormal protein aggregation and hyperactivation of the cGAS-STING. Importantly, blocking DNA sensing pathways suppressed inflammation, rescued senescence in affected individual-derived MSCs, and alleviated premature aging in LmnaR527C/R527C mice. These findings establish a homozygous LMNA pathogenic variant as a key driver of inflammation-driven segmental progeroid syndrome and highlight DNA sensing pathways as promising therapeutic targets.

Aging of hematopoietic stem cells (HSCs) impairs hematopoietic regeneration and differentiation, contributing to immune aging, systemic inflammation, and reduced lifespan. Strategies to rejuvenate aged HSCs and restore immune homeostasis remain limited. Here, we identify ferroptotic stress as a key contributor to HSC aging. Mechanistically, increased sphingosine metabolism elevates sphingosine-1-phosphate (S1P), which suppresses HDAC activity and enhances H3K9 acetylation to upregulate lysophosphatidylcholine acyltransferase 2 (Lpcat2), thereby promoting the accumulation of pro-ferroptotic phospholipids in aged HSCs. Genetic or pharmacological inhibition of sphingosine kinase 2 (Sphk2) reduces S1P levels, suppresses Lpcat2 expression, and attenuates ferroptotic stress in aged mouse and human HSCs. Notably, Sphk2 inhibition improves HSC function, restores immune homeostasis, and modestly extends lifespan in aged mice. Together, these findings identify an S1P-HDAC-Lpcat2 pathway linking epigenetic and lipid remodeling to ferroptotic stress and highlight sphingosine metabolism as a therapeutic target for HSC aging.