Longevity Papers

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.

The potential of senescent cell clearance to extend healthspan and delay the onset of age-related diseases has driven the development of innovative senotherapeutics. Thus, niosome-based gene therapy has emerged as a promising strategy to overcome the off-target limitations of first-generation senolytics, senomorphics, and senoreverts. In the present study, we investigated two new niosome formulations for genetically modifying primary umbilical cord stroma senescent MSCs (UC-MSCs) in a Palbociclib-induced senescent model, using non-senescent UC-MSCs as a control. These niosomes were formulated by fixing the cationic lipid composition (1,2-di-O-octadecenyl-3 trimethylammonium propane, DOTMA, D) and varying the non-ionic surfactants (polysorbate 20, P20, or polysorbate 80, P80) and the helper lipids (chloroquine, CQ, or cholesterol, CH) (DP20CQ and DP80CH, respectively) at two mole ratios (1:2:1 and 1:2:2 for DP20CQ; 1:2:2 and 1:2:4 for DP80CH). Results on transfection revealed that the DP20CQ formulations outperformed those with DP80CH in both UC-MSCs phenotypes from four different donors. Notably, DP20CQ niosomes prepared at 10/1 and 15/1 DOTMA/DNA ratios achieved the highest transgene expression levels in senescent UC-MSCs, surpassing even the commercial reagent Lipofectamine. Further, DP20CQ formulations exhibited adequate physicochemical properties for transfection and promoted a marked endosomal escape, particularly at the DOTMA/DNA ratio 10/1, without compromising cell viability. These findings underscore the value of niosomes as robust gene delivery vehicles for senescent cells in therapeutic antiaging strategies.

Aging drives molecular changes that impair cellular and tissue function. Lipids are central to membrane structure, signaling and energy storage, yet their remodeling during aging remains unclear. Here, using cross-species, multi-tissue lipidomics, we identify elongation of lipid acyl chains as a conserved hallmark of aging across mice, Caenorhabditis elegans, Drosophila and humans. Similar lengthening occurs during the progression of human heart disease, whereas dietary restriction shortens cardiac lipids in mice. Integrated analyses reveal that aging is characterized by a shift toward longer lipids accompanied by depletion of shorter species, indicating ratiometric remodeling. Following this, we identify the lipid remodeler Plb1 as a regulator of this process, with expression correlating with lifespan in mice and genetic analyses supporting a causal role in human frailty. In C. elegans, Plb1 knockdown reverses lipid elongation and extends lifespan in a lipid-length-dependent manner. Together, these findings establish lipid chain length remodeling as a conserved, actionable hallmark of aging.

Cellular senescence contributes to age-associated tissue dysfunction through persistent growth arrest, metabolic remodeling, and altered communication with immune and stromal cells. Senolytic therapies preferentially eliminate susceptible senescent cells, while senomorphic therapies modulate harmful senescence-associated activities. Nanoparticle engineering can improve the delivery of these agents through cargo protection, surface functionalization, and controlled release. Surface ligands can promote cellular uptake, and components responsive to lysosomal β-galactosidase, acidic pH, reactive oxygen species, or protease activity can regulate cargo release. The selectivity of these mechanisms depends on biological features that vary among senescent populations and also occur in other cellular states. This review examines how material composition and physicochemical properties influence target recognition, intracellular transport, therapeutic activity, and safety. Representative platforms are evaluated across fibrotic, musculoskeletal, metabolic, oncologic, and neurodegenerative disease models, with particular attention to mitochondrial delivery, immune-mediated clearance, nucleic-acid modulation, and microbiome interactions. Preclinical findings are considered alongside human senotherapy studies, which have primarily evaluated small-molecule drug regimens and yielded preliminary or mixed outcomes. Clinical development requires reproducible manufacturing, pharmacokinetic characterization of both carrier and cargo, and assessment of immunotoxicity and delayed organ injury in older hosts. Progress depends on matching a defined pathological cell population to an appropriate delivery strategy and demonstrating an advantage in therapeutic index or sustained functional outcomes against relevant comparators, including clinically feasible non-nanoparticle treatments where available.

Autophagy dysfunction and senescence are established drivers of aging, but their potential interaction remains poorly understood. Here we show that age-related decline of chaperone-mediated autophagy (CMA), a pathway for selective lysosomal protein degradation, changes senescent cell properties and impairs their immune clearance. CMA-deficient cells undergo senescence but acquire proteomic, metabolic and secretory features resembling those in aged senescent cells. Their senescence-associated secretory phenotype exhibits enhanced pro-senescence effects on neighboring cells and inhibits macrophage CMA, which impairs their ability to engulf senescent cells. Accordingly, blockage of CMA specifically in macrophages increases senescent cell accumulation in mice and delays senescence resolution during wound healing. Conversely, pharmacological CMA activation reduces senescent cell burden in aged mice and disease severity in a pulmonary fibrosis mouse model. Our findings identify CMA decline as a driver of senescent cell persistence and highlight CMA upregulation as a promising strategy to promote senescence resolution in aged organisms.

Population aging drives a parallel increase in muscle atrophy and cognitive decline, two major causes of disability in older adults. Mitochondrial dysfunction and chronic inflammation are core drivers of aging, with pyroptosis serving as a critical link between them. However, conventional single‑technique approaches capture only fragmented, static information and fail to bridge molecular events with whole‑organism phenotypes. This review introduces a unique integrative perspective that weaves established multimodal technologies ranging from molecular interaction analysis and absolute quantification to cellular metabolic and electrophysiological recordings, tissue clearing and laser microdissection, and finally to in vivo imaging and body composition analysis into a coherent, cross‑scale chain of evidence. By applying this paradigm to the mitochondria‑pyroptosis axis, we reveal how oxidative mitochondrial DNA enhances NLRP3 binding, how aged cells exhibit metabolic vulnerability and electrophysiological susceptibility, how pyroptotic hotspots form with spatial heterogeneity in tissues, and how pyroptosis signals quantitatively correlate with the decline in muscle mass and cognitive function. The core contribution of this review is the methodological framework of multimodal integration that enables causal tracing from molecular triggers to functional outcomes. This paradigm offers a transferable strategy for dissecting complex aging mechanisms and provides a theoretical foundation for targeting the mitochondria‑pyroptosis axis in precision anti‑aging interventions.

Cellular senescence, a key feature of ageing, involves irreversible cell cycle arrest and the secretion of pro-inflammatory senescence-associated secretory phenotype (SASP) factors, which contribute to tissue degeneration and age-related diseases. Targeting senescent cells with senolytics, senomorphics and anti-ageing therapies marks a major shift in translational geroscience, with the potential to delay or reverse age-related conditions. A systematic review and narrative synthesis was conducted in accordance with PRISMA 2020 guidelines. Eligible human clinical studies evaluating pharmacological interventions targeting cellular senescence were included, comprising randomized and nonrandomized clinical trials and pilot studies reporting clinical, functional or senescence-associated outcomes. Data on study characteristics, interventions, efficacy, safety and senescence-associated biomarkers were extracted and synthesized qualitatively. Six completed clinical studies were included in the evidence synthesis, with one additional ongoing clinical trial identified separately. Senolytic interventions, particularly dasatinib plus quercetin, showed preliminary improvements in selected functional outcomes and reductions in senescence-associated biomarkers, while senomorphic and mTOR-targeting interventions demonstrated effects on selected tissue and immune-related outcomes. Reported adverse events were generally mild or manageable, but small sample sizes and short follow-up limited assessment of uncommon and long-term safety risks. Current evidence suggests that pharmacological targeting of cellular senescence is feasible and may produce measurable biological and functional effects in humans, but evidence remains insufficient to establish clinical efficacy or long-term safety. Senolytic and senomorphic strategies should therefore be considered investigational rather than established therapies. Larger, adequately powered randomized trials with standardized senescence biomarkers, clinically meaningful outcomes, longer follow-up and systematic safety assessment are needed.

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.

DE-SWAN is a commonly used method to study how large ensembles of omics biomarkers change across the life course. It has been used to demonstrate apparent repeated accelerations and decelerations of aging rates across the life course, including 2-3 peaks of aging-related changes. This result contradicts what is expected based on the demography of aging and known biological mechanisms. Here, we use simulations to study the robustness of DE-SWAN to the age distribution of the study sample and to choice of window size. We show that under many realistic scenarios, DE-SWAN is highly sensitive to factors unrelated to the underlying rates of change in aging biology. This calls into question the results of previous analyses that have attributed DE-SWAN peaks to acceleration and deceleration of aging. We conclude that the method is unreliable for studying rates of change across the life course under most circumstances.