Human hallmarks of sarcopenia include muscle weakness and a blunted response to exercise. Nicotinamide N-methyltransferase inhibitors (NNMTis) increase strength and promote the regenerative capacity of aged muscle, thus offering a promising treatment for sarcopenia. Since human hallmarks of sarcopenia are recapitulated in aged (24-month-old) mice, we treated mice from 22 to 24 months of age with NNMTi, intensive exercise, or a combination of both, and compared skeletal muscle adaptations, including grip strength, longitudinal running capacity, plantarflexor peak torque, fatigue, and muscle mass, fiber type, cross-sectional area, and intramyocellular lipid (IMCL) content. Exhaustive proteome and metabolome analyses were completed to identify the molecular mechanisms underlying the measured changes in skeletal muscle pathophysiology.

Remarkably, NNMTi-treated aged sedentary mice showed ~ 40% greater grip strength than sedentary controls, while aged exercised mice only showed a 20% increase relative to controls. Importantly, the grip strength improvements resulting from NNMTi treatment and exercise were additive, with NNMTi-treated exercised mice developing a 60% increase in grip strength relative to sedentary controls. NNMTi treatment also promoted quantifiable improvements in IMCL content and, in combination with exercise, significantly increased gastrocnemius fiber cross-sectional area. Detailed skeletal muscle proteome and metabolome analyses revealed unique molecular mechanisms associated with NNMTi treatment and distinct molecular mechanisms and cellular processes arising from a combination of NNMTi and exercise relative to those given a single intervention.

These studies suggest that NNMTi-based drugs, either alone or combined with exercise, will be beneficial in treating sarcopenia and a wide range of age-related myopathies.

Cardiovascular and metabolic drugs are frequently repurposed due to their diverse molecular mechanism in many diseases. With various molecular mechanisms found in the aging process, cardiometabolic drugs possess the potential to delay aging. For instance, aspirin and statins are potentially beneficial for cancer, or the pleiotropic effect of metformin in cancer, cardiovascular disease, and dementia in diabetic patients. Of note, aspirin and metformin could extend the lifespan of rodents. Our systematic review primarily focused on animal studies, with additional consideration given to clinical trials and their protocols.

Dramatic growth in the variety of longevity medicines that are being identified from animal studies is not always successfully translated to clinical applications. Aspirin treatment failed to prevent mortality and morbidity in healthy older adult people and potentially increased the hemorrhagic risk in those people. In parallel, metformin could not prolong the lifespan in drosophila and rather increased the mortality in female mice. Moreover, the clinical trials of metformin, such as MILES (Metformin In Longevity Study), showed the enhancement of longevity-related gene expressions, but the valid molecular mechanisms by which metformin facilitates this activity remain unknown.

Analysis of 49 animal trials and 10 clinical trial registries show that various cardiovascular and metabolic drugs have the potential to target lifespan. Metformin, acarbose, and aspirin are the three most studied drugs in animal trials. Aspirin and acarbose are the promising ones, whereas metformin exhibits various results. In clinical trial registries, metformin, omega-3 fatty acid, acarbose, and atorvastatin are currently cardiometabolic drugs that are repurposed to target aging. Published clinical trial results show great potential for omega-3 and metformin in healthspan.

The present findings showed that a lower total cholesterol (TC) level was associated with elevated all-cause mortality risk in a population of oldest-old adults (aged ≥85 years). When TC level was used as a continuous variable, the mortality risk increased by 12% with each 1 mmol/L reduction in TC. This is consistent with findings from several previous studies, which demonstrated that a low TC level was a risk factor for all-cause mortality in older people. This could be explained by the increased risk of non-cardiovascular mortality (e.g., from cancers and infections). After identifying this inverse association, we further explored the lower limit of TC and found a continuous increment of all-cause mortality risks when TC levels fell below 3.40 mmol/L. This indicates that a TC level lower than 3.40 mmol/L is associated with higher mortality risk among oldest-old adults. To our knowledge, this is the first study to clarify the lower TC cutoff point in this population, and it has been suggested that lower TC levels are associated with frailty and chronic disease in seniors, which further increases mortality risk.

Some researchers suggest that higher TC levels are associated with better nutritional and chronic health status in the oldest old population; thus, individuals with elevated TC levels are more likely to live longer. In the present study, we attempted to exclude the potential effect of dietary or physiological factors by including these variables in the model. In our study, self-reported diabetes, heart disease, and stroke were not significantly associated with all-cause mortality, and thus not included as covariates in the final multivariable models. The predictive value of traditional risk factors for mortality may diminish in the oldest old compared to younger populations, as supported by some previous studies.

As for dietary factors, fresh fruit consumption and fish consumption were protective factors in the multivariable model, whereas daily consumption of eggs and sugar were risk factors for all-cause mortality, which is consistent with previous findings. Adjustment for dietary behaviors and chronic health conditions did not alter the protective effect of TC on all-cause mortality, indicating that the association between TC and all-cause mortality is independent of nutritional status.

Although the biological pathways that link TC to mortality are poorly understood, several mechanisms may explain this inverse association. For example, blood lipids, which are an important component of cell membranes, may affect cell electrophysiology by modulating the distribution and function of some ion channels. Low TC levels may contribute to the pathogenesis of some common diseases in older people, such as atrial fibrillation. Another potential mechanism is that TC may regulate inflammatory markers such as C-reactive protein and attenuate the biological response to inflammation. Therefore, individuals with low TC levels may be more vulnerable to physiological disorders because of enhanced inflammation.

There is mounting unmet need to discover new clinical therapies for the prevention and treatment of calcification in the human circulatory system. This process of cardiovascular calcification is a significant factor in the more than 18 million lives claimed globally each year by heart disease. Stenosis of vasculature associated with blood flow restriction and heart valve calcification is a common health disorder in people of all ages, genders, and ethnic backgrounds, is associated with other comorbidities, and is the most prevalent form of heart disease in patients 65 and older. Yet beyond invasive valve implants, there are no viable alternative drug therapies or clinical treatment options available.

The evolutionary success of invertebrate and vertebrate organisms through geological time has relied on their ability to harness the precipitation of thermodynamically unstable amorphous calcium phosphate (ACP) before it spontaneously transforms into crystalline hydroxyapatite (HAP). While ACP calcification is fundamental to an organism's ability to precipitate essential hard parts such as bone and teeth, the capacity of ACP to morphologically shape-shift and atomically rearrange also results in various soft tissue pathologies.

Previous research on aortic valve calcification has primarily focused on cellular and molecular pathophysiology processes, including extracellular matrix biochemistry and biomechanics, but has not specifically targeted the etiological processes recorded by the calcification deposits themselves. This is because standard microscopy techniques for pathological screening include stains that dissolve ACP and/or transform ACP to HAP in tissue sections, while x-ray diffraction cannot resolve the short-range ordering of ACP. Since 1975, several comprehensive reviews refer to four basic research studies that have identified ACP as the primary agent of aortic valve and arterial calcification by combining electron diffraction, standard microscopy, and microprobe analyses with optical microscopy on unstained histological cryosections. Now, a half century later, rigorous examination specifically targeting the role of ACP in cardiovascular calcification remains to be completed.

Here, we use transdisciplinary geology, biology, and medicine approaches prove that leaflet calcification is driven by amorphous calcium phosphate (ACP), ACP at the threshold of transformation toward hydroxyapatite (HAP), and cholesterol biomineralization. A paragenetic sequence of events is observed that includes: (1) original formation of unaltered leaflet tissues: (2) individual and coalescing 100's nm- to 1 μm-scale ACP spherules and cholesterol crystals biomineralizing collagen fibers and smooth muscle cell myofilaments; (3) osteopontin coatings that stabilize ACP and collagen containment of nodules preventing exposure to the solution chemistry and water content of pumping blood, which combine to slow transformation to HAP; (4) mm-scale nodule growth via ACP spherule coalescence, diagenetic incorporation of altered collagen and aggregation with other ACP nodules; and (5) leaflet diastole and systole flexure causing nodules to twist, fold their encasing collagen fibers and increase stiffness. These in vivo mechanisms combine to slow leaflet calcification and establish previously unexplored hypotheses for testing novel drug therapies and clinical interventions.

The major signalling mechanisms that regulate lifespan across species include ERK, STK11 (also known as LKB1), AMPK, mTORC1, and IGF1-insulin modules. These pathways are collectively perturbed in old age to activate hallmarks of ageing, which include mitochondrial dysfunction, inflammation, and cellular senescence. In aged organisms, the AMPK-mTORC1 axis is uniquely important for metabolic health, with notable effects in adipose tissue, and therapeutic inhibition of mTOR extends lifespan in mice.

The importance of chronic sterile inflammation for ageing pathologies is increasingly recognized and inflammation itself is a central hallmark of ageing. In simplified terms, ageing is associated with a dysfunctional adaptive immune system that is characterized by immunosenescence and thymic involution along with inappropriate activation of innate immune genes such as IL-6, The pro-inflammatory signalling factors NF-κB and JAK-STAT3 are specifically implicated in ageing and JAK inhibitors can alleviate age-related dysfunction.

We proposed that IL-11, a pro-inflammatory and pro-fibrotic member of the IL-6 family, may promote age-associated pathologies and reduce lifespan. This premise was founded on studies showing that IL-11 can activate ERK-mTORC1 and/or JAK-STAT3, the observation that IL-11 is upregulated in older people, and the fact that IL-11 is increasingly recognized to have a role in senescence, a hallmark of ageing. Here, using a range of genetic and pharmacological approaches, we tested the hypothesis that IL-11 signalling has a negative effect on healthspan and lifespan in mice.

Deletion of Il11 or Il11ra1 protects against metabolic decline, multi-morbidity, and frailty in old age. Administration of anti-IL-11 antibodies to 75-week-old mice for 25 weeks improves metabolism and muscle function, and reduces ageing biomarkers and frailty across sexes. In lifespan studies, genetic deletion of Il11 extended the lives of mice of both sexes, by 24.9% on average. Treatment with anti-IL-11 from 75 weeks of age until death extends the median lifespan of male mice by 22.5% and of female mice by 25%.

Together, these results demonstrate a role for the pro-inflammatory factor IL-11 in mammalian healthspan and lifespan. We suggest that anti-IL-11 therapy, which is currently in early-stage clinical trials for fibrotic lung disease, may provide a translational opportunity to determine the effects of IL-11 inhibition on ageing pathologies in older people.

Recent studies show that human organs age at different rates similar to what has been reported in animals, which suggests a need for organ-specific measures of biological age. Previously developed organ age estimates include those developed from clinical metrics of organ function (glomerular filtration rate, blood pressure, etc), clinical blood chemistry, brain MRI scans, immune cell DNA methylation profiles, and the levels of organ-specific proteins in blood plasma. Many questions regarding the reproducibility and utility of organ age estimates remain. For example, it is unclear the extent to which organ age estimates are stable across cohorts and longitudinal sampling, are sensitive to organ-specific diseases and modifiable lifestyle choices, and whether they predict mortality independent of each other and established aging biomarkers. Furthermore, it is unclear which organs are key to longevity in humans.

Organ-derived plasma protein signatures derived from aptamer protein arrays track organ-specific aging, disease, and mortality in humans, but the robustness and clinical utility of these models and their biological underpinnings remain unknown. Here, we estimate biological age of 11 organs from 44,526 individuals in the UK Biobank using an antibody-based proteomics platform to model disease and mortality risk. Organ age estimates are associated with future onset of heart failure (heart age HR=1.83), chronic obstructive pulmonary disease (lung age HR=1.39), type II diabetes (kidney age HR=1.58), and Alzheimer's disease (brain age HR=1.81) and sensitive to lifestyle factors such as smoking and exercise, hormone replacement therapy, or supplements.

Remarkably, the accrual of aged organs progressively increases mortality risk while a youthful brain and immune system are uniquely associated with disease-free longevity. These findings support the use of plasma proteins for monitoring organ health and the efficacy of drugs targeting organ aging disease.

Restraining or slowing ageing hallmarks at the cellular level have been proposed as a route to increased organismal lifespan and healthspan. Consequently, there is great interest in anti-ageing drug discovery. However, this currently requires laborious and lengthy longevity analysis. Here, we present a novel screening readout for the expedited discovery of compounds that restrain ageing of cell populations in vitro and enable extension of in vivo lifespan.

We monitored DNA methylation changes accompanying long-term passaging of adult primary human cells in culture. This enabled us to develop, test, and validate the CellPopAge Clock, an epigenetic clock with underlying algorithm, unique among existing epigenetic clocks for its design to detect anti-ageing compounds in vitro. Additionally, we measured markers of senescence and performed longevity experiments in vivo in Drosophila, to further validate our approach to discover novel anti-ageing compounds.

We find that the CellPopAge Clock can detect decelerated passage-based ageing of human primary cells treated with rapamycin or trametinib, well-established longevity drugs. We then utilise the CellPopAge Clock as a screening tool for the identification of compounds which decelerate ageing of cell populations, uncovering novel anti-ageing drugs, torin2 and dactolisib (BEZ-235). We demonstrate that delayed epigenetic ageing in human primary cells treated with anti-ageing compounds is accompanied by a reduction in senescence and ageing biomarkers. Finally, we extend our screening platform in vivo by taking advantage of a specially formulated holidic medium for increased drug bioavailability in Drosophila. We show that the novel anti-ageing drugs, torin2 and dactolisib (BEZ-235), increase longevity in vivo.

A mechanistic connection between aging and development is largely unexplored. Through profiling age-related chromatin and transcriptional changes across 22 murine cell types, analyzed alongside previous mouse and human organismal maturation datasets, we uncovered a transcription factor binding site (TFBS) signature common to both processes. Early-life candidate cis-regulatory elements (cCREs), progressively losing accessibility during maturation and aging, are enriched for cell-type identity TFBSs. Conversely, cCREs gaining accessibility throughout life have a lower abundance of cell identity TFBSs but elevated activator protein 1 (AP-1) levels.

We implicate transcription factor (TF) redistribution toward these AP-1 TFBS-rich cCREs, in synergy with mild downregulation of cell identity TFs, as driving early-life cCRE accessibility loss and altering developmental and metabolic gene expression. Such remodeling can be triggered by elevating AP-1 or depleting repressive H3K27me3. We propose that AP-1-linked chromatin opening drives organismal maturation by disrupting cell identity TFBS-rich cCREs, thereby reprogramming transcriptome and cell function, a mechanism hijacked in aging through ongoing chromatin opening.

Trained immunity is characterized by epigenetic and metabolic reprogramming in response to specific stimuli. This rewiring can result in increased cytokine and effector responses to pathogenic challenges, providing nonspecific protection against disease. It may also improve immune responses to established immunotherapeutics and vaccines. Despite its promise for next-generation therapeutic design, most current understanding and experimentation is conducted with complex and heterogeneous biologically derived molecules, such as β-glucan or the Bacillus Calmette-Guérin (BCG) vaccine. This limited collection of training compounds also limits the study of the genes most involved in training responses as each molecule has both training and nontraining effects.

Small molecules with tunable pharmacokinetics and delivery modalities would both assist in the study of trained immunity and its future applications. To identify small molecule inducers of trained immunity, we screened a library of 2,000 drugs and drug-like compounds. Identification of well-defined compounds can improve our understanding of innate immune memory and broaden the scope of its clinical applications. We identified over two dozen small molecules in several chemical classes that induce a training phenotype in the absence of initial immune activation - a current limitation of reported inducers of training. A surprising result was the identification of glucocorticoids, traditionally considered immunosuppressive, providing an unprecedented link between glucocorticoids and trained innate immunity. We chose seven of these top candidates to characterize and establish training activity in vivo. In this work, we expand the number of compounds known to induce trained immunity, creating alternative avenues for studying and applying innate immune training.

Senescent retinal pigment epithelium (RPE) was linked to the onset of age-related macular degeneration (AMD), with senolytic agents assessed as potential treatments for AMD. A fact that has been seldom considered among the plethora of processes that are affected and, in turn, effected by cellular senescence (an adaptive cell response to stressors effected by an inflammatory secretome) is that of intercellular communication. In the case of the RPE, its functional and anatomical ties to the choroid are as much, if not more so, functionally relevant as those with the neuroretina.

A study applying a combined approach using bulk RNAseq, scRNAseq, and microarray RPE transcriptomics was able to draw substantial inferential data pertaining to intercellular communication between the RPE and the choroid. Intercellular communications between RPE cells and stromal elements involved in aging and senescence pertained notably to VEGF, BMP- and tenascin-mediated pathways, i.e., these pathways scored higher when mediating interactions between senescent cell populations. Consistently, AMD-derived patient samples scored higher overall in terms of senescence, and bulk RNAseq data showed a positive correlation in score increase with age.

These findings potentially support employing anti-aging therapies such as senolytic pharmacologic compounds to prevent or ameliorate progression to AMD, as well as underscore the necessity of more rigorous investigation into the interplay of senescence and cell-to-cell communication.

The cellular stress response is regulated at the transcriptional, translational, and post-translational levels by a family of heat shock transcription factors (HSFs) that are expressed and maintained in an inactive state under non-stress conditions. HSFs, essential for all organisms to survive to acute or chronic stress, are also important for normal development and lifespan-enhancing pathways, and the repertoire of HSF targets has thus expanded well beyond the heat shock genes.

Post-translational regulation of HSFs is emerging to integrate the metabolic state of the cell with stress biology, whereby controlling fundamental aspects of the health of the proteome and aging. In addition to this, the KEAP1/Nrf2/ARE pathway is the basis of the cellular defense. Induction of this pathway has been shown to be protective against various stress conditions. On the other side, under conditions of Nrf2 deficiency with failure to upregulate this pathway, increased sensitization and accelerated disease pathogenesis have been demonstrated.

Transcription factor Nrf2, under basal conditions, is continuously targeted for ubiquitination and proteasomal degradation by KEAP1, a protein acting as a repressor. It is well defined now that many inducers of the Nrf2 pathway chemically modify specific cysteine residues within KEAP1, leading to the loss of its ability to target Nrf2 for degradation. Subsequently, Nrf2 levels accumulate and hence activate transcription of NRF2-dependent genes which encode a large network of cytoprotective proteins, including those that are involved in the metabolism and transport of a wide array of endobiotics and xenobiotics, proteins that have antioxidant functions, as well as those that participate in the synthesis, utilization, and regeneration of glutathione and NAD(P).

Several phytochemicals act through the activation of transcription factor Nrf2. Under basal conditions, these protective systems do not operate at maximum capacity but can be induced to higher activity levels by redox-active compounds, such as hormetic nutrients, thus reducing the risks of developing malignancies and multiple chronic diseases.

The autoimmune disease systemic lupus erythematosus - known as lupus - affects more than 1.5 million people in the US. It can result in life-threatening damage to multiple organs including the kidneys, brain, and heart. The causes of this disease have long been unclear. Existing treatments often fail to control the disease and have unintended side effects of reducing the immune system's ability to fight infections. But now researchers have discovered a molecular defect that promotes the pathologic immune response in lupus and show that reversing this defect may potentially reverse the disease.

The scientists report a new pathway that drives disease in lupus. There are disease-associated changes in multiple molecules in the blood of patients with lupus. Ultimately, these changes lead to insufficient activation of a pathway controlled by the aryl hydrocarbon receptor (AHR), which regulates cells' response to environmental pollutants, bacteria, or metabolites, a substance created when the body breaks down food, drugs, chemicals or its own tissue. Insufficient activation of AHR results in too many immune cells that promote the production of disease-causing autoantibodies.

To show this discovery can be leveraged for treatments, the investigators returned the AHR-activating molecules to blood samples from lupus patients. This seemed to reprogram these lupus-causing cells into a type of cell that may promote wound healing from the damage caused by this autoimmune disease. "We found that if we either activate the AHR pathway with small molecule activators or limit the pathologically excessive interferon in the blood, we can reduce the number of these disease-causing cells. If these effects are durable, this may be a potential cure."

Induction of parathyroid hormone (PTH) signaling using the PTH-derived peptide - teriparatide, has demonstrated strong bone-promoting effects in patients with osteoporosis. These effects are mediated by osteogenesis, the process of bone formation involving the differentiation and maturation of bone-forming cells called osteoblasts. However, PTH induction is also associated with the differentiation of macrophages into osteoclasts, which are specialized cells responsible for bone resorption. Although, bone remodeling by osteoblasts and osteoclasts is crucial for maintaining skeletal health, PTH-induced osteoclast differentiation can decrease treatment efficacy in patients with osteoporosis. However, precise molecular mechanisms underlying the dual action of PTH signaling in bone remodeling are not well understood.

Researchers conducted a series of experiments to identify druggable target genes downstream of PTH signaling in osteoblasts. The researchers treated cultured mouse osteoblast cells and mice with teriparatide. They then assessed gene expression changes induced by PTH in both the cultured cells and bone cells isolated from the femurs of the treated animals, using advanced RNA-sequencing analysis. Among several upregulated genes, they identified a novel PTH-induced gene - 'Gprc5a', encoding an orphan G protein-coupled receptor, which has been previously explored as a therapeutic target. However, its precise role in osteoblast differentiation had not been fully understood.

The researchers examined the effect of Gprc5a downregulation on osteoblast proliferation and differentiation. Notably, while PTH induction alone did not affect cell proliferation, Gprc5a knockdown resulted in an increase in the expression of cell-cycle-related genes and osteoblast differentiation markers. These findings suggest that Gprc5a suppresses osteoblast proliferation and differentiation. Diving deeper into the molecular mechanisms underlying the effects of Gprc5a, in PTH-induced osteogenesis, the researchers identified Activin receptor-like kinase 3 (ALK3), a bone morphogenetic protein (BMP) signaling pathway receptor, as an interacting partner of Gprc5a. Overexpression of Gprc5a led to suppression of BMP signaling.

Overall, these findings reveal that Gprc5a, a novel inducible target gene of PTH, negatively regulates osteoblast proliferation and differentiation by partially suppressing BMP signaling. Gprc5a can thus, be pursued as a novel therapeutic target while devising treatments against osteoporosis.

The female reproductive system is one of the first to age in humans, resulting in infertility and endocrine disruptions. The aging ovary assumes a fibro-inflammatory milieu which negatively impacts gamete quantity and quality as well as ovulation. Here we tested whether the systemic delivery of anti-inflammatory (Etanercept) or anti-fibrotic (Pirfenidone) drugs attenuates ovarian aging in mice. We first evaluated the ability of these drugs to decrease the expression of fibro-inflammatory genes in primary ovarian stromal cells. Whereas Etanercept did not block Tnf expression in ovarian stromal cells, Pirfenidone significantly reduced Col1a1 expression.

We then tested Pirfenidone in vivo where the drug was delivered systemically via mini-osmotic pumps for 6-weeks. Pirfenidone mitigated the age-dependent increase in ovarian fibrosis without impacting overall health parameters. Ovarian function was improved in Pirfenidone-treated mice as evidenced by increased follicle and corpora lutea number, AMH levels, and improved estrous cyclicity. Transcriptomic analysis revealed that Pirfenidone treatment resulted in an upregulation of reproductive function-related genes at 8.5 months and a downregulation of inflammatory genes at 12 months of age. These findings demonstrate that reducing the fibroinflammatory ovarian microenvironment improves ovarian function, thereby supporting modulating the ovarian environment as a therapeutic avenue to extend reproductive longevity.

Nicotinamide adenine dinucleotide (NAD) is essential for many enzymatic reactions, including those involved in energy metabolism, DNA repair, and the activity of sirtuins, a family of defensive deacylases. During aging, levels of NAD+ can decrease by up to 50% in some tissues, the repletion of which provides a range of health benefits in both mice and humans. Whether or not the NAD+ precursor nicotinamide mononucleotide (NMN) extends lifespan in mammals is not known. Here we investigate the effect of long-term administration of NMN on the health, cancer burden, frailty and lifespan of male and female mice.

Without increasing tumor counts or severity in any tissue, NMN treatment of males and females increased activity, maintained more youthful gene expression patterns, and reduced overall frailty. Reduced frailty with NMN treatment was associated with increases in levels of Anerotruncus colihominis, a gut bacterium associated with lower inflammation in mice and increased longevity in humans. NMN slowed the accumulation of adipose tissue later in life and improved metabolic health in male but not female mice, while in females but not males, NMN increased median lifespan by 8.5%, possible due to sex-specific effects of NMN on NAD+ metabolism.

Together, this data shows that chronic NMN treatment delays frailty, alters the microbiome, improves male metabolic health, and increases female mouse lifespan, without increasing cancer burden. These results highlight the potential of NAD+ boosters for treating age-related conditions and the importance of using both sexes for interventional lifespan studies.