Fight Aging!

Later stages of Alzheimer's disease and other tauopathies are characterized by the aggregation of altered tau protein, and a toxic surrounding biochemistry that provokes inflammation and destroys neurons. So far little headway has been made towards therapies that can halt tau pathology, by clearing harmful tau or preventing its formation. Given the several decade span of intense effort devoted to the clearance of amyloid-β in the brain before success ultimately emerged, we might expect that much more remains to be accomplished in order to reach the same point for tau. Unfortunately, many discoveries in the neurodegenerative field are approaches that cannot be curative, and this is the case here. The peptide discussed can only reduce tau pathology in mouse models of tauopathy, not eliminate it.

Neurodegenerative disorders such as Alzheimer's disease (AD), Corticobasal Degeneration (CBD), and Progressive Supranuclear Palsy (PSP) are characterized by tau aggregation, neuroinflammation, and progressive cognitive decline. Although metabolic dysregulation and neuropeptide imbalance have been linked to these disorders, the functional consequences of this imbalance and its reversal remain poorly understood. Our previous work identified chromogranin A (CgA), the gene encoding a pro-hormone for several metabolic peptides, as a key regulator of tau pathology.

Here, we investigate Catestatin (CST), a CgA-derived peptide, for its role in modulating tauopathy. We report marked reductions in CST levels and an increase in Pancreastatin (PST) in the hippocampus and cortex of AD brains, as well as in the frontal cortex of CBD and the basal ganglia of PSP. CST-supplementation in cortical neuronal cultures and organotypic slice cultures (OTSC) reduced Tau phosphorylation and aggregation. In vivo, CST administration to PS19 tauopathy mice decreased pathological Tau species, attenuated gliosis, improved cognitive function, and reduced amyloid burden and neuroinflammation in 5xFAD mice.

Mechanistically, CST reduced epinephrine levels in PS19 and 5xFAD mice, suppressed Protein Kinase A hyperactivation in PS19 and OTSC, and revealed a link between CST deficiency, adrenergic stress signaling, tauopathy-mediated neurodegeneration, and the therapeutic potential of CST supplement.

Link: https://doi.org/10.1016/j.ymthe.2026.09.022

Researchers here provide an initial proof of concept demonstration of a novel foundation for replacing lost visual capacity in cases of retinal degeneration, without addressing the underlying pathology that causes loss of function in photoreceptor cells. Recall that direct stimulation of retinal cells by grid electrodes implanted in the retina has been used to produces a poor substitute for actual vision, but a substitute that allows blind people at least some capacity to navigate and even read. Here, researchers introduce light sensitive nanoparticles into the retina that can in principle provide the basis for a more refined artificial substitute for normal vision. Based on the results of the electrode grids, one would expect the result to be a view of the world painted in glowing shades of phosphenes at various intensities.

The possibility to electrically stimulate living tissue creates new opportunities for therapeutic applications. Interfaces between biology and nanomaterials open an array of possibilities for non-genetic modulation of bioelectric activity with subcellular spatiotemporal control. Nanoparticles (NPs) have shown to be able to build tight interfaces with both intra- and extracellular membranes. Importantly, light can trigger electrochemical or photothermal effects at the semiconductor NP/cellular interface acting as a leadless electrophysiological modulator.

Here, drawing inspiration from photosynthesis, we develop hollow-sphere graphitic carbon nitride nanoparticles (hg-C3N4 NPs) that can modulate biological activity from subcellular processes to whole-tissue function. The homogeneous hg-C3N4 NPs show responsiveness to light via both photoelectrochemical and photothermal mechanisms and can be spontaneously internalized with excellent cytocompatibility.

We demonstrate that hg-C3N4 nanoparticles can be safely delivered and elicit measurable cortical and behavioural light responses in a model of advanced retinal degeneration. The application of hg-C3N4 NPs to porcine retinal tissue ex vivo confirms their modulation capability to directly activate retinal ganglion cell activity under light-emitting diode photostimulation.

Link: https://doi.org/10.1038/s41551-026-01773-w

PD-L1 found on the surface of cells is a well known immune checkpoint protein. When it binds to the receptor PD-1 found on the surface of T cells and B cells, it acts to suppress immune activity. This is a necessary brake to avoid runaway immune reactions, but because it is also abused by cancer cells to shield them from the immune system, the cancer research community has given a great deal of attention to this and other forms of immune checkpoint. Checkpoint inhibitors such as antibodies for PD-L1 are a well established class of drug intended to enable the immune system to better attack cancerous cells.

In today's open access paper, researchers report on the results of delivering a PD-L1 antibody directly into the brains of Alzheimer's disease model mice. Past research has suggested that the more usual intravenous delivery outside the brain can help improve clearance of protein aggregates in the brain by immune cells, but the mechanism would have to be fairly indirect. The immune systems of body and brain are quite distinct from one another, separated by the blood-brain barrier, and in normal circumstances only small numbers of immune cells from the body can enter the brain. Would a more direct targeting of brain cells produce a larger effect?

While the authors of today's paper view checkpoint inhibition in terms of enabling greater clearance of protein aggregates by a more active population of immune cells, it seems plausible that clearance of senescent cells in the brain is equally important. Like cancerous cells, senescent cells in aged tissues have been found to employ immune checkpoint activation to preserve themselves from clearance by the immune system. Senescent cells are clearly detrimental to the aging brain, a major contribution to disruptive chronic inflammation. It is plausible that checkpoint inhibition could reduce the burden of senescent cells in an aging brain. Alas, the researchers here restrict themselves to measuring only some functional aspects of brain cell populations, so whether or not this is the case in the present study is unclear.

Targeting glial PD-1/PD-L1 restores microglial homeostasis and reduces neuronal hyperactivity in an Alzheimer's disease model

Immunotherapy targeting the immune checkpoint pathway, particularly the programmed cell death protein 1/programmed death-ligand 1 (PD-1/PD-L1) axis, has emerged as a promising strategy for treating Alzheimer's disease (AD). Previous studies have suggested that the systemic administration of anti-PD-L1 antibody reduces amyloid-β burden and improves cognitive outcomes in AD mouse models, primarily by activating peripheral immune responses and promoting the recruitment of monocyte-derived macrophages (MDMs) into the brain. However, these studies have primarily focused on peripheral immune cells.

Unlike the systemic approaches, our study emphasizes the direct modulation of PD-1/PD-L1 signaling within the brain and its implications for glial and neuronal functions. Microglia, the brain's intrinsic immune cells, are central to maintaining neuronal homeostasis; they monitor neuronal activities and modulate synaptic functions. In AD, microglia often exhibit a dysfunctional state characterized by impaired phagocytosis, reduced motility, and altered gene expression. Astrocytes also play a vital role in maintaining brain homeostasis by modulating neuronal activities, thereby regulating synaptic transmission and supporting microglial function. PD-L1 expressed on astrocytes has been implicated in neuroimmune interactions, but its specific role in AD has not been fully investigated.

Increased PD-1 and PD-L1 levels in microglia and astrocytes show features analogous to their sustained expression in exhausted peripheral immune cells during chronic infections and tumors, in which they help suppress heightened immune responses. In AD, such upregulation of PD-1/PD-L1 may contribute to glial dysfunction, with potential consequences for immune surveillance and neuronal modulation. Consequently, targeting glial PD-1/PD-L1 signaling directly within the brain could provide a promising strategy to restore glial and neuronal function.

In this study, we investigated the effects of direct intracortical anti-PD-L1 administration on microglial function, neuronal activity, and amyloid-β pathology in a 5xFAD mouse model using real-time in vivo two-photon microscopy. Seven days after the intracortical injection, the anti-PD-L1 treatment effectively rescued microglial process motility and restored spontaneous neuronal calcium activity, while reducing amyloid-β plaque burden and increasing plaque-associated microglia. Furthermore, astrocyte-specific PD-L1 knockdown showed effects similar to those resulting from the inhibition of the glial PD-1/PD-L1 pathway. Collectively, our findings suggest that brain-intrinsic glial PD-1/PD-L1 modulation reduces amyloid-β pathology along with restoring functional interactions among microglia, astrocytes, and neurons.

Researchers here provide a proof of concept for the use of Raman spectroscopy to non-invasively measure the burden of senescent cells in an imaged tissue. This works because Raman imaging can provide distinct signatures of different molecules via scattering of photons. Provided the field of imaging is sufficiently constrained, it is possible to produce results that measure differing abundances of specific molecules in different cells. Senescent cells exhibit a range of upregulated and downregulated proteins and other molecules, so in principle creating a system to assess the presence of senescent cells is just a matter of putting in the work to construct and validate a specific implementation.

Aging and tissue repair involve heterogeneous remodeling across transcriptional, biochemical, and cellular dimensions, yet prevailing definitions rely on isolated molecular markers that obscure how these states co-evolve. Here we present RamanOmics, a multimodal framework integrating label-free hyperspectral Raman imaging with single-nucleus RNA sequencing and spatial transcriptomics to link biochemical states with transcriptional programs at single-cell spatial resolution.

Applied to young and old mouse lung and skin, RamanOmics reveals tissue-specific programs: lung senescent cells are enriched for extracellular matrix remodeling and transforming growth factor-β signaling, whereas skin senescence is dominated by epidermal differentiation genes (Krt10, Lor, and Sbsn). Across tissues, we identified a conserved lipid-linked Raman signature marking p21+ senescent cells and developed a machine learning-derived, multimodal barcode enabling nondestructive senescence identification in situ. In a mouse wound-healing model, RamanOmics reveals reactivation of epidermal differentiation genes (Krt10, Lor and Sbsn) in senescent cells, alongside increased lipid-associated Raman signatures.

Taken together, RamanOmics provides a tissue-agnostic framework for scalable, multimodal profiling of cellular states.

Link: https://doi.org/10.1038/s43587-026-01219-7

One of the more interesting new concepts in aging research is that repeated activation of the DNA damage response may cause epigenetic changes in the management of nuclear DNA structure that are characteristic of aging. It neatly explains how stochastic DNA damage to unused DNA sequences can possible contribute to aging. It also frames partial epigenetic reprogramming as a true rejuvenation therapy, one of the reasons why there is a great deal of funding for that line of work. Is it actually the case, however? The mechanistic evidence to date is suggestive, but as usual the question is less whether the mechanism exists and more whether it provides a meaningful contribution to degenerative aging. Maybe those epigenetic changes are largely the result of other processes, for example. Here, a researcher discusses the evidence to date, and proposes tests that one might consider running in order to provide a better set of answers regarding the contribution of the DNA damage response to aging than presently exist.

Aging is multi-causal, yet its molecular hallmarks may converge on a few upstream integrating nodes. We advance the hypothesis that chronic, largely mutation-independent overactivation of the DNA damage response (DDR) is one such node, dysregulating the cell's intact guardian pathways - the tumor-suppressor networks and their negative regulators - to induce senescence, deplete stem-cell pools, and drive inflammaging. Unlike cancer, where mutations inactivate these guardians, aging more often reflects functional dysregulation of wild-type pathways, either chronically overactivated (p53, p16INK4a) or epigenetically silenced (SIRT1, FOXO3, NRF2, Klotho). That the very programs guarding against cancer can, when chronically engaged, come to drive aging we term the guardian paradox.

We organize 16 candidate axes - which we term the aging axis - across three evidence tiers, mapped onto the hallmarks of aging, outlining for each a conceptual diagnostic signature and an illustrative restoration strategy, with all numeric biomarker bands and vector details as non-clinical placeholders. We set this DDR-integrator hypothesis against mitochondria-, proteostasis-, and reprogramming-first models and pre-specify longitudinal, mediation, and head-to-head tests that could support, demote, or refute it. No integrated human interventional data yet exist; we therefore present a falsifiable research agenda, not a therapeutic protocol.

Link: https://doi.org/10.18632/aging.206416

Type 1 conventional dendritic cells are a subclass of dendritic cell known to be an important component of the immune response to pathogens and cancerous cells, particularly focused on stimulating the activity of cytotoxic T cells. The cancer research community, as is often the case when it comes to specific components of the immune system, has led the way in generating a better understanding of these cells, and so much of the present literature is focused on their role in cancer. Generally speaking, patients with more type 1 conventional dendritic cells tends to exhibit better outcomes, because the cancer will be more aggressively attacked by the immune system. Unfortunately, the population of type 1 conventional dendritic cells declines with age.

Today's open access paper assembles existing data to provide a coherent viewpoint on the interconnected mechanisms leading to the age-related loss of type 1 conventional dendritic cells, and proposes a readily available solution, albeit one involving cell therapy. A number of interventions assessed by the cancer research community have been shown to somewhat restore dendritic cell function, but none of them are sufficient because they each only address once small part of the overall cause of the loss of type 1 conventional dendritic cells. The authors of today's paper propose that an existing approach to the ex vivo production of type 1 conventional dendritic cells for anti-cancer cell therapy will solve the problem by providing cells that were not exposed to the specific changes in an aged biochemistry that form the root cause of the issue.

A proposed convergent molecular chain linking senescence, cancer, and chronic infection to a correctable failure of dendritic cell instruction

Three convergent phenomena in biomedical research have lacked a unified mechanistic explanation: the dendritic cell dysfunction of aging, the immune evasion of cancer, and the tolerogenic bias of chronic infection. In each setting, the specific cell responsible for instructing effector immunity, the type 1 conventional dendritic cell (cDC1), is numerically depleted, functionally silent, or both, leading to loss of its bioactive IL-12p70 output.

The cDC1 is defined at the lineage level by its dependence on the transcription factor IRF8, which is required for cDC1 specification, survival, and the capacity to produce IL-12p70. The IRF8 locus is regulated by a BATF3-dependent enhancer architecture that has been shown to operate as a bistable switch with no stable intermediate state: a committed cDC1 is either IRF8-high and surveillance-competent or IRF8-low and tolerogenic. The switch does not sit between these states. This architectural property is central to understanding why partial interventions have produced only partial results.

We propose that aging, cancer, and chronic infection converge on a single molecular chain that forces this switch into the off position. The chain has four steps, each of which is individually established in the published literature. Senescence-associated secretory phenotype (SASP) cytokines activate STAT3 in hematopoietic progenitors; STAT3 recruits DNMT1 and EZH2 to the IRF8 locus; dual DNA methylation and histone methylation installs a bistable silencing state with no stable intermediate; IL-12 transcription and cDC1 instruction collapse.

Any correction that leaves the upstream SASP intact and attempts to unlock IRF8 in situ must overcome both DNA methylation and H3K27me3 on a bistable locus whose low-affinity enhancer architecture is biased toward the off state. Pharmacological attempts to do this, DNMT inhibitors, EZH2 inhibitors, JAK/STAT3 inhibitors, IL-6 blockade, have produced partial restoration of dendritic-cell function in preclinical settings but not durable correction. The logic of the chain explains why: each of these interventions targets a single node while the remaining nodes continue to reinforce silencing.

An alternative approach bypasses the architecture rather than unlocking it. A cDC1 manufactured ex vivo in a STAT3-free environment, with IFN-γ priming and TLR3 engagement, is never exposed to the sustained STAT3 signal required for DNMT and EZH2 recruitment. Its IRF8 locus is not methylated because the conditions that drive methylation are absent from the bioreactor. The α-type-1 polarized dendritic cell (α-DC1) protocol developed in the early 2000s produces precisely such a cell. The α-DC1 protocol has been evaluated clinically, most directly in recurrent malignant glioma, within a broader body of dendritic-cell vaccine trials in melanoma and other solid tumors. The clinical data in these trials are consistent with the framework. Interpreted within the framework presented here, the α-DC1 functions as a replacement instructor for a cell population whose native equivalents have been silenced.

Suppression of cancer is a necessary component of species longevity, and finding out how exactly cancer incidence is in some cases dramatically reduced is one of the primary goals for the field of comparative biology. Here, researchers survey known cancer-associated sequences across the genomes of long-lived and short-lived species, and see that sequences are more conserved in long-lived species. Patterns of epigenetic modifications to the genome at these locations also exhibit differences in long-lived species. Thus one component of reduced cancer risk in these species involves specific sequence differences in oncogenes and related genes, and different expression of oncogenes in circumstances relevant to induction of cancer.

Recently, accumulated evidence has shown that longer-lived species, such as naked mole rats, elephants, and some bat species display enhanced resistance to cancer. In this study, we identify genomic sites in 58 mammalian species that are homologous to human cancer-associated regions and compare their evolutionary dynamics to those of cancer-unrelated sites. By contrasting mutation rates in longer-lived versus shorter-lived species, we evaluate whether evolutionary constraint at these loci correlates with lifespan or body size. Because epigenetic modifications are intimately linked to oncogenesis, and synonymous changes can affect tumorigenesis by perturbing m6A deposition, we also examine the distribution of 5mC and m6A marks at cancer-associated versus unrelated sites across the two lifespan groups.

While overall evolutionary rates at cancer-associated loci do not differ significantly between long-lived and short-lived species, cancer-associated sites show greater evolutionary conservation relative to non-cancer sites within long-lived mammals but not within short-lived mammals. Furthermore, long-lived species exhibit a pronounced enrichment of m6A at cancer-associated loci (based on m6A modification sites derived exclusively from male samples) despite lower global m6A levels. Notably, tumor suppressor genes in long-lived mammals harbor proportionally more m6A-modified transcripts, suggesting a potential association between messenger RNA methylation and post-transcriptional regulation at cancer-relevant loci. Together, these results suggest that enhanced sequence conservation at cancer loci, coupled with targeted mRNA modification, may be part of a multilayered molecular strategy that reduces cancer risk in long-lived mammals.

Link: https://doi.org/10.1038/s41467-026-76479-3

Here find a small slice of programmed aging consideration focused on some of the changes in cognitive function that take place in later life. The researchers argue that a shift in focus to integration of information, characterized by a loss of precision in episodic memory, is adaptive and selected for in older individuals. It is an interesting point of view, though given the tools the research community has today it would be challenging to determine whether any specific age-related alteration in neural circuitry and cognitive function in the brain is adaptive change versus change that is a response to damage and loss of function.

Prevailing theories of cognitive aging depict late life as a period of compensatory decline - an effort to preserve performance despite progressive neural deterioration. We propose instead that aging represents a continuation of development: a genetically conserved, adaptive reorganization of memory systems that parallels the brain's earlier-life transitions. Drawing on convergent molecular, network, behavioral, and comparative evidence, we argue that the well-documented decline in episodic-memory precision reflects a deliberate recalibration of plasticity from hippocampal to cortical circuits, favoring semantic integration and schematic stability over rapid encoding of novel details.

This shift, we suggest, is not a workaround for loss but an evolved optimization suited to the cognitive ecology of late life, when accumulated knowledge, social insight, and intergenerational teaching become primary adaptive functions. The resulting semantic mode of cognition supports narrative coherence, emotional regulation, and wisdom, distinguishing normal aging from pathological derailments such as Alzheimer's disease. We outline testable predictions across longitudinal, neuroimaging, and computational domains and reinterpret constructs like cognitive reserve as expressions of this developmental reallocation. By reframing aging as purposeful maturation rather than compensation, the adaptive-aging hypothesis positions late-life cognition as a distinct, evolutionarily honed phase of human development.

Link: https://doi.org/10.1177/17456916261469175

It is well understood in the aging research community that the lack of a useful, consensus measure of biological age or pace of biological aging is a considerable hindrance to progress. If researchers could quickly measure the pace of aging or the state of aging in a robust way, then discovery and optimization of interventions would proceed a great deal more rapidly. At present, too many suboptimal lines of research are maintained despite the likely lack of effectiveness at the end of the day, and the discovery of new approaches to slow aging and extend life is a slow and expensive process; even in mice, life span studies take years to run.

There are a great many age-related changes in health, biochemistry, and physical function that can be measured, and many of those have their advocates. The "just measure grip strength and get on with it already" faction is a sizable one. Various aging clocks produce decent correlations with age-related mortality and morbidity. And so forth. But the challenge with all of the existing options is that we have no idea as whether then can be trusted to accurately reflect the effects of any new class of intervention. Maybe they will overstate the outcome. Maybe they will understate it. The only way to find out is to calibrate assays against interventions in long-running and expensive studies. And so development remains stuck in the slow lane.

In today's open access paper, researchers propose one possible way forward to an incrementally better situation. The idea is to look through the existing high quality studies of slowed aging in mice conducted by the Interventions Testing Program, and find common biochemical and metabolic measures that appear in mice exhibiting slowed aging. This seems relevant to the classes of therapy that slow aging by provoking cellular stress responses, repair and maintenance and defense activities that improve cell function: calorie restriction, calorie restriction mimetics, and the like. It seems tough to argue that metrics uncovered via these studies could then be applied to completely different approaches to therapy that do not touch on these shared stress response systems, such as senolytics or stem cell therapies, however.

Aging rate indicators and the search for anti-aging drugs

Evidence that drugs, diets, and single-gene mutations can slow aging and extend the healthy lifespan of mammals has begun to convert biogerontology from an observational science into one based on interventions that could provide people with additional years of healthy, productive life. However, the research and development of anti-aging drugs is hampered by the lack of instantaneous and continuous measures of the rate of aging itself. This article presents recent work on anti-aging drugs that are effective in mice, provides evidence for candidate "aging rate indicators" (ARIs), and outlines a roadmap for translating these into clinical research to slow aging in humans.

Thus far, 14 agents or combinations have significantly increased the lifespan of mice in studies conducted under the Interventions Testing Program (ITP) of the National Institute on Aging, often when initiated in late adulthood. Recent evidence suggests that many, perhaps all, interventions that slow aging in mice induce common, shared changes in physiological status and molecular pathways. We have proposed 12 such mechanisms as candidate ARIs, i.e., measurable outcomes that reflect a slow-aging state and that could discriminate between normal mice (and perhaps humans) and those exposed to effective anti-aging interventions - thereby accelerating research.

Research priorities now include testing the robustness of these ARIs, extending them to include plasma constituents, elucidating the mechanisms through which diverse interventions alter them, uncovering the links between the ARIs and late-life diseases, and extending research to dogs, non-human primates, and humans. The growing recognition of the legitimacy and promise of evidence-based interventions resulting from aging biology should elevate this field to a level of urgency and respect comparable to that of current research on individual age-related conditions.

Researchers have started on the long process of transferring promising genes from long-lived species into short-lived species, one by one, with each such transfer as a test of how important that specific difference is to the progression of aging and species longevity. Differences in the presence of hyaluronan in the extracellular matrix are thought to improve the health and resilience of long-lived naked-mole rats, and so researchers generated a mouse lineage that manufactures naked mole rat hyaluronan. The result is improved healthspan, and so now researchers are beginning to assess this novel lineage of mice more deeply. Here, for example, researchers show that this alteration to hyaluronan doesn't have any effect on age-related hearing loss.

Approximately one in three adults aged 65-74 years reports hearing difficulty, including age-related hearing loss (AHL, presbycusis). The C57BL/6 mouse is widely used in preclinical AHL research because it develops AHL relatively early. Calorie restriction (CR) attenuates AHL and improves healthspan and longevity in this strain. A recently developed transgenic C57BL/6 mouse expressing naked mole-rat hyaluronan synthase 2 (nmrHas2), which produces very high molecular mass hyaluronan (vHMM-HA), also exhibits improved healthspan, reduced inflammaging, and increased longevity. Therefore, we evaluated nmrHas2 mice for evidence of alleviated AHL.

The goal of this experiment was to determine whether ubiquitous expression of the nmrHas2 transgene, including within the cochleae, attenuated AHL. Our results indicate that a genetic intervention that had previously been shown to improve healthspan, reduce inflammaging, and increase longevity in C57BL/6 mice did not attenuate AHL, i.e., these outcomes were decoupled in nmrHas2 mice, which contrasts with outcomes following CR. This points to differences in the mechanisms of action of these two interventions, at least within the cochleae.

Link: https://doi.org/10.3389/fragi.2026.1936677

Many approaches to modestly slow aging in short-lived species involve a mild mitochondrial dysfunction that that somewhat increases the level of reactive oxygen species generated in the course of producing adenosine triphosphate (ATP) to power the cell. Reactive oxygen species react with and damage molecular machinery throughout the cell, damage that needs to be repaired. The cell reacts with an increase in repair and maintenance activities that address oxidative damage and other forms of damage, producing a net benefit to function. Here, researchers investigate one portion of how this response is regulated, looking at the metabolism of nematode worms.

The reactive oxygen species superoxide is generated by mitochondria during the process of producing energy. While superoxide can cause oxidative damage to the cell, we and others have shown that a mild increase in mitochondrial superoxide extends longevity in multiple model organisms. To elucidate the molecular mechanisms involved, we identified transcriptional changes in mitochondrial superoxide dismutase deletion mutants (sod-2 worms) using RNA sequencing. sod-2 mutants exhibit a number of changes in nuclear gene expression resulting from elevated mitochondrial superoxide suggesting that mitochondria-to-nucleus signaling is contributing to their longevity.

Gene ontology enrichment analysis demonstrated that genes involved in innate immunity and cuticle formation are significantly upregulated in sod-2 worms. To identify kinases involved in this lifespan-extending pathway, we completed a targeted RNA interference screen to examine the contribution of selected kinases to sod-2 longevity. From this screen, we found 25 kinases which are required for the long lifespan of sod-2 mutants including mak-2, which has a role in a kinase signaling pathway involved in axon regeneration. Disruption of mak-2 specifically reduces sod-2 lifespan but not wild-type longevity and also decreases resistance to multiple exogenous stressors. In examining other genes that act with mak-2 in established signaling pathways, we identified a SEK-3/PMK-3/MAK-2/CEBP-1 signaling pathway that is specifically required for sod-2 longevity but not wild-type lifespan.

Combined these results suggest a novel role for kinases with established roles in axon regeneration in promoting longevity through a mitochondria-to-nucleus signaling pathway.

Link: https://doi.org/10.1016/j.redox.2026.104385

The cGAS protein is a sensor for mislocalized DNA in the cell cytoplasm, and responds by triggering STING, a regulator of the inflammatory response to damage and dysfunction. The cGAS-STING interaction produces some fraction of the maladaptive chronic inflammation characteristic of aging, as, among other reasons, mitochondrial dysfunction tends to spill mitochondrial DNA fragments into the cell cytoplasm. Nothing in the cell has only one purpose, however, and cGAS is also involved in the regulation of the DNA damage response in the cell nucleus. It is known to inhibit homologous recombination of double strand breaks, for example.

An examination of cGAS in different species suggests that different variants can aid or hinder late life health via their actions in either the DNA repair context or the chronic inflammation context. Introducing naked mole rat cGAS into mice improves DNA repair and reduces the impact of aging, and a rare lineage of humans exhibits a variant form of cGAS that reduces cGAS-STING activation, and thus late life inflammation.

cGAS does serve a useful purpose, despite producing a maladaptive contribution to degenerative aging. This is demonstrated in today's open access paper, in which disabling cGAS entirely in killifish does not extend life. Benefits are provided by removing its maladaptive activity, and harms are caused by removing its helpful activity. This is characteristic of interventions in the regulation of inflammation: chronic inflammation is harmful, but the normal short term inflammatory response serves a necessary purpose in tissue maintenance, and both run through the same regulatory pathways, making it challenging to intervene in a selective way.

Loss of killifish cGAS attenuates age-related signatures but does not affect organismal life span

A major source of inflammaging stems from chronic activation of the nucleic acid-sensing innate immune pathway cGAS/STING. Cytosolic DNA fragments arising from DNA damage, mitochondrial dysfunction, or infection bind cGAS to stimulate production of 2'3'-cGAMP (cGAMP). Subsequently, cGAMP activates STING, triggering the type I interferon response and inflammatory cytokine production. While this pathway is important for host defense, its chronic stimulation promotes age-related pathology. The cGAS-STING pathway also plays a central role in cellular senescence. Cytosolic DNA in these cells is detected by cGAS, triggering the senescence-associated secretory phenotype (SASP), whose persistence fosters chronic inflammation. Hence, limiting cGAS/STING pathway activity may improve late-life health.

Despite its importance in age-related disease, the effect of cGAS/STING on lifespan itself remains unknown. Here, we elucidated the role of cGAS in the short-lived African turquoise killifish Nothobranchius furzeri, a vertebrate model of aging. In this work, we used CRISPR-engineering to knock out killifish cGAS to examine its impact on senescence and aging. We hypothesized that cGAS loss would improve health and extend life. Although cGAS deficiency reduced senescence markers, attenuated age-related transcriptional changes, and maintained higher proliferative capacity with age, lifespan was unchanged, indicating that cGAS is not limiting for organismal longevity.

Researchers here take a very broad tour of the established literature on the comparative biology of aging in long lived species of all sorts, picking from those that can live more than 250 years, whether plant or animal, and comparing reported differences in biochemistry both between species and between individuals of the same species. It seems just as interesting to ask which mechanisms are important in individual variation in pace of aging in a long-lived species as to ask why the species is long-lived in the first place. The usual challenges exist, in that one can identify differences in biochemistry that seem reasonably likely to contribute to differences in longevity, but establishing the relative importance of each contribution is near impossible without some form of intervention that sabotages or enhances one mechanism in isolation of all of the others.

Certain molecular processes shape the lifespan of each species and each individual. Deciphering these processes, which underlie the diversity in lifespan across and within species can help us better understand how they evolved and why. Such knowledge may inform the design of effective strategies towards increasing human and other species' healthspan and lifespan. Here, we consider 101 species that live past 250 years, including the longest-living beings on Earth. Among these species, 90 are plants and only 11 are animals. Some barely reach an age of 250 years, while others live for up to 80,000 years. Few, such as the freshwater planarian and the Turritopsis dohrnii jellyfish, are considered potentially immortal. None of these species are mammals; indeed, no known mammal lives for over 250 years.

We surveyed the genetic, transcriptional, proteomic, metabolomic, regeneration-, stress-, and cancer-related components of intraspecific and interspecific lifespan variation, across these species. We examined whether the mechanisms regulating intraspecific lifespan variation across these species are the same or different from mechanisms regulating interspecific lifespan variation. We identified several similarities: both types of variation include mechanisms related to DNA maintenance, stemness, and stress management. Such mechanisms are also typical of early developmental stages and germ cells. Nonetheless, caution should be exercised when attempting to draw robust conclusions based on available data, given the lack of in-depth molecular studies on the healthspan and lifespan across thousands of individuals and species, the methodological variation across published studies, and our partial understanding of the interplay between physiology and the environment across species.

Link: https://doi.org/10.18632/aging.206419

Rationing of sugar in the United Kingdom in the years immediately following the Second World War forms a natural experiment in the long term effects of changes in human nutrition that can be explored in great detail given the establishment of the UK Biobank. Researchers here show that lower sugar intake in early life correlates with improved later life health, reduced biological age measures, and reduced mortality. A number of other natural experiments around the time of the Second World War have been used to explore the effects of calorie restriction in early life, but this particular episode of rationing is a way to separate lower sugar intake from overall calorie restriction; it is interesting to see positive results.

Excessive intake of free or added sugars is strongly linked to childhood dental caries and is also associated with higher risks of incident obesity, type 2 diabetes (T2D), cardiovascular disease (CVD), obesity-related cancers, and dementia in adulthood. Britain's post-World War II sugar rationing provides a unique natural experiment. Unlike famine, rationing constrained access to added sugars without broad caloric deprivation, offering a rare opportunity to isolate the long-term impact of early-life sugar reduction to determine the impact on a variety of ageing-related outcomes.

Exposure to sugar rationing during the first 1,000 days of life is associated with a 9% lower incidence of hallmark-related disease, with a hazard ratio of 0.91, and a 19% lower risk of all-cause mortality. Mediation analysis indicates that the survival association is statistically mediated, by approximately 60%, through differences in incident hallmark-related disease. Rationed individuals show 1.0-1.2-year younger biological ages across multiple clocks and lower organ ages, particularly in the lung, heart, and liver. Proteomic profiling identifies 47 altered proteins, with enrichment of adenosine monophosphate-activated protein kinase (AMPK) and longevity pathways and suppression of mechanistic target of rapamycin (mTOR) signaling.

Link: https://doi.org/10.1038/s41467-026-76257-1

A range of gene therapies are presently available in the medical tourism community of clinics outside the US and Europe, largely originating with a small number of companies such as BioViva Sciences and Triple Helix Science. These gene therapies tend to involve intramuscular (targeting muscle) or intranasal (targeting the brain) delivery of a modern adeno-associated virus (AAV) vector, such as AAV8 or AAV9. While AAV therapies have exhibited a concerning risk of life-threatening immune response when injected systemically at high doses, lower doses used in conjunction with local delivery appear to be relatively safe. The genes delivered by these gene therapies include follistatin for muscle growth, VEGF for vascular growth, and some well-known genes hoped to improve the state of the aging body and brain such as telomerase, SIRT1, and so forth. One can argue that perhaps the largest body of direct and practical experience in the implementation of gene therapies is now this community, outside the regulated medical community, and publishing relatively little of the data on what works that they have accumulated.

So it is interesting to see the Triple Helix folk here reporting on their experience in the use of grip strength as a biomarker of aging to assess the results of gene therapies intended to improve function. One of the largest challenges in the matter of measuring aging is the uncertainty over whether any given biomarker that appears to work well in normal aging will then continue to work well when a patient receives some form of regenerative or anti-aging therapy. The best way to stress test a biomarker is to gather data on how it actually performs given a range of different types of regenerative or anti-aging therapy. Until recent years, the range of available interventions known to reliably affect aging has been quite narrow, essentially diet and exercise and first generation stem cell therapies, with newcomers like senolytics and mTOR inhibitors starting be used widely enough for data to emerge. Now, AAV gene therapies can provide a dozen or more very different effects to assess.

Grip strength as a systems biomarker of aging: neuromuscular junction constraints and biomarker decoupling in gene therapy

Grip strength occupies a privileged position among biomarkers of biological aging. Meta-analyses encompassing hundreds of thousands of participants consistently demonstrate that grip strength predicts all-cause mortality with effect sizes comparable to established risk factors such as systolic blood pressure. This predictive relationship persists across age groups, ethnicities, and disease states, extending beyond mortality to encompass cognitive decline, disability onset, hospitalization risk and quality of life measures. Yet the mechanistic basis for this remarkable predictive breadth remains incompletely understood. The dominant interpretation treats grip strength as a convenient proxy for overall muscle mass or general frailty. We argue this view is incomplete and increasingly problematic. When grip strength remains predictive after statistical adjustment for lean mass - while lean mass alone loses significance - something beyond simple muscularity must be at work.

This interpretive challenge becomes urgent as longevity medicine enters a new era. Longevity gene therapies are being explored in early translational and compassionate-use settings and include follistatin for muscle enhancement, klotho for multi-system protection, FOXO3 for stress resistance, hTERT for telomere extension, SIRT1 for metabolic regulation, PGC-1α for mitochondrial biogenesis, VEGF for vascular function, and FGF21 for metabolic health. These therapies represent a fundamental shift from observational aging assessment to interventional aging modification.

The central question this article addresses is: How should clinicians interpret grip strength changes in patients receiving longevity gene therapies? We propose that grip strength predicts mortality because it integrates information from multiple aging systems. We highlight the neuromuscular junction (NMJ) as a particularly critical and often-overlooked rate-limiting factor, noting that age-related strength loss (∼2.5-4% annually) outpaces mass loss (∼0.6-1% annually) by two-to fivefold - a disparity attributable in large part to NMJ deterioration. Critically, we argue that follistatin's anabolic efficacy is contingent on intact NMJ integrity, with denervated muscle fibers exhibiting a blunted net anabolic response despite elevated follistatin expression - creating a therapeutic paradox wherein mass gains can occur without proportional functional improvement. We provide a conceptual analysis of how each therapy may influence grip strength, predict decoupling risk based on the breadth of systems affected, outline plausible timing windows for intervention, and propose a heuristic framework for clinical interpretation.