The Achilles' heel of senescent cells: from transcriptome to senolytic drugs

Targeting cIAP2 in a novel senolytic strategy prevents glioblastoma recurrence after radiotherapy

Glioblastomas (GBM) are routinely treated with high doses of ionizing radiation (IR), yet these tumors recur quickly, and the recurrent tumors are highly therapy resistant. Here, we report that IR-induced senescence of tumor cells counterintuitively spurs GBM recurrence, driven by the senescence-associated secretory phenotype (SASP). We find that irradiated GBM cell lines and patient derived xenograft (PDX) cultures senesce rapidly in a p21-dependent manner. Senescent glioma cells upregulate SASP genes and secrete a panoply of SASP factors, prominently interleukin IL-6, an activator of the JAK-STAT3 pathway. These SASP factors collectively activate the JAK-STAT3 and NF-κB pathways in non-senescent GBM cells, thereby promoting tumor cell proliferation and SASP spreading. Transcriptomic analyses of irradiated GBM cells and the TCGA database reveal that the cellular inhibitor of apoptosis protein 2 (cIAP2), encoded by the BIRC3 gene, is a potential survival factor for senescent glioma cells. Senescent GBM cells not only upregulate BIRC3 but also induce BIRC3 expression and promote radioresistance in non-senescent tumor cells. We find that second mitochondria-derived activator of caspases (SMAC) mimetics targeting cIAP2 act as novel senolytics that trigger apoptosis of senescent GBM cells with minimal toxicity towards normal brain cells. Finally, using both PDX and immunocompetent mouse models of GBM, we show that the SMAC mimetic birinapant, administered as an adjuvant after radiotherapy, can eliminate senescent GBM cells and prevent the emergence of recurrent tumors. Taken together, our results clearly indicate that significant improvement in GBM patient survival may become possible in the clinic by eliminating senescent cells arising after radiotherapy.

Aging immunity: unraveling the complex nexus of diet, gut microbiome, and immune function

Aging is associated with immune senescence and gut dysbiosis, both of which are heavily influenced by the diet. In this review, we summarize current knowledge regarding the impact of diets high in fiber, protein, or fat, as well as different dietary components (tryptophan, omega-3 fatty acids, and galacto-oligosaccharides) on the immune system and the gut microbiome in aging. Additionally, this review discusses how aging alters tryptophan metabolism, contributing to changes in immune function and the gut microbiome. Understanding the relationship between diet, the gut microbiome, and immune function in the context of aging is critical to formulate sound dietary recommendations for older individuals, and these personalized nutritional practices will ultimately improve the health and longevity of the elderly.

Insights into age-related osteoporosis from senescence-based preclinical models and human accelerated aging paradigms

Preclinical models of age-related osteoporosis have been developed based on the accumulation and clearance of senescent cells. The former include animal models based on telomere dysfunction and focal radiation; the latter based on genetic and pharmacological targeting (i.e., removal) of senescent cells. The weight of evidence using these models suggests that cellular senescence plays a key role in the pathophysiology of aging-onset bone loss with the senescence-associated secretory phenotype (SASP) mediating local and systemic deleterious effects on the skeleton. Mitochondrial dysfunction has also been implicated in senescence and age-related comorbidities, including osteoporosis, and knock-in mutations in the mtDNA polymerase gamma (Polg) gene in mice may recapitulate similar respiratory chain complex defects in aged individual with osteoporosis. This and other contributions to senile osteoporosis may also be identified by the careful evaluation of non-genetic paradigms of human accelerated aging. Premature aging syndromes, especially those with a prominent bone loss phenotype, include clinical scenarios of skeletal unloading, premature ovarian failure and survival from childhood cancers. These non-hereditary progeroid syndromes implicate the involvement of lineage switching to an adipogenic fate, inhibition of Wnt signaling, increased osteoclastogenesis and activation frequency of osteoclasts, as well as the substantial burden of senescent cell accumulation.

Tracing Cellular Senescence in Bone: Time-Dependent Changes in Osteocyte Cytoskeleton Mechanics and Morphology

Aging-related bone loss significantly impacts the growing elderly population globally, leading to debilitating conditions such as osteoporosis. Senescent osteocytes play a crucial role in the aging process of bone. This longitudinal study examines the impact of continuous local and paracrine exposure to senescence-associated secretory phenotype (SASP) factors on biophysical and biomolecular markers in osteocytes. Significant cytoskeletal stiffening in irradiated (IR) osteocytes are found, accompanied by expansion of F-actin areas and a decline in dendritic integrity. These changes, correlating with alterations in pro-inflammatory cytokine levels and osteocyte-specific gene expression, support the reliability of biophysical markers for identifying senescent osteocytes. Notably, local accumulation of SASP factors have a more pronounced impact on osteocyte biophysical properties than paracrine effects, suggesting that the interplay between local and paracrine exposure can substantially influence cellular aging. This study underscores the importance of osteocyte mechanical and morphological properties as biophysical markers of senescence, highlighting their time dependence and differential effects of local and paracrine SASP exposure. Collectively, the investigation into biophysical senescence markers offers unique and reliable functional hallmarks for the non-invasive identification of senescent osteocytes, providing insights that can inform therapeutic strategies to mitigate aging-related bone loss.

Deciphering the role of cytokines in aging: Biomarker potential and effective targeting

Aging is often characterized by chronic inflammation, immune system dysregulation, and cellular senescence with chronically elevated levels of pro-inflammatory cytokines. These small glycoproteins are mainly secreted by immune cells, mediating intercellular communication and immune system modulation through inflammatory signaling. Their pro- and anti-inflammatory effects make them a noteworthy research topic as well as a promising ally in combating inflammation and the aging process. Cytokines exert a synergistic role in aging and disease and may prove useful biomarkers of tissue-specific dysregulation, disease diagnosis and monitoring, presenting potential therapeutic options as anti-inflammatory and senolytic medications. In this review, we address the cellular and molecular mechanisms implicating cytokines in the aging process and related diseases, highlighting their biomarker potential. We focus on the current therapeutic strategies, including specific pharmaceutical agents, supplements, a balanced diet, and healthy habits such as exercise, stress management, and caloric restriction.

Systemic aging fuels heart failure: Molecular mechanisms and therapeutic avenues

Systemic aging influences various physiological processes and contributes to structural and functional decline in cardiac tissue. These alterations include an increased incidence of left ventricular hypertrophy, a decline in left ventricular diastolic function, left atrial dilation, atrial fibrillation, myocardial fibrosis and cardiac amyloidosis, elevating susceptibility to chronic heart failure (HF) in the elderly. Age-related cardiac dysfunction stems from prolonged exposure to genomic, epigenetic, oxidative, autophagic, inflammatory and regenerative stresses, along with the accumulation of senescent cells. Concurrently, age-related structural and functional changes in the vascular system, attributed to endothelial dysfunction, arterial stiffness, impaired angiogenesis, oxidative stress and inflammation, impose additional strain on the heart. Dysregulated mechanosignalling and impaired nitric oxide signalling play critical roles in the age-related vascular dysfunction associated with HF. Metabolic aging drives intricate shifts in glucose and lipid metabolism, leading to insulin resistance, mitochondrial dysfunction and lipid accumulation within cardiomyocytes. These alterations contribute to cardiac hypertrophy, fibrosis and impaired contractility, ultimately propelling HF. Systemic low-grade chronic inflammation, in conjunction with the senescence-associated secretory phenotype, aggravates cardiac dysfunction with age by promoting immune cell infiltration into the myocardium, fostering HF. This is further exacerbated by age-related comorbidities like coronary artery disease (CAD), atherosclerosis, hypertension, obesity, diabetes and chronic kidney disease (CKD). CAD and atherosclerosis induce myocardial ischaemia and adverse remodelling, while hypertension contributes to cardiac hypertrophy and fibrosis. Obesity-associated insulin resistance, inflammation and dyslipidaemia create a profibrotic cardiac environment, whereas diabetes-related metabolic disturbances further impair cardiac function. CKD-related fluid overload, electrolyte imbalances and uraemic toxins exacerbate HF through systemic inflammation and neurohormonal renin-angiotensin-aldosterone system (RAAS) activation. Recognizing aging as a modifiable process has opened avenues to target systemic aging in HF through both lifestyle interventions and therapeutics. Exercise, known for its antioxidant effects, can partly reverse pathological cardiac remodelling in the elderly by countering processes linked to age-related chronic HF, such as mitochondrial dysfunction, inflammation, senescence and declining cardiomyocyte regeneration. Dietary interventions such as plant-based and ketogenic diets, caloric restriction and macronutrient supplementation are instrumental in maintaining energy balance, reducing adiposity and addressing micronutrient and macronutrient imbalances associated with age-related HF. Therapeutic advancements targeting systemic aging in HF are underway. Key approaches include senomorphics and senolytics to limit senescence, antioxidants targeting mitochondrial stress, anti-inflammatory drugs like interleukin (IL)-1β inhibitors, metabolic rejuvenators such as nicotinamide riboside, resveratrol and sirtuin (SIRT) activators and autophagy enhancers like metformin and sodium-glucose cotransporter 2 (SGLT2) inhibitors, all of which offer potential for preserving cardiac function and alleviating the age-related HF burden.

HRK downregulation and augmented BCL-xL binding to BAK confer apoptotic protection to therapy-induced senescent melanoma cells

Senescent cells are commonly detected in tumors after chemo and radiotherapy, leading to a characteristic cellular phenotype that resists apoptotic cell death. In this study, we used multiple melanoma cell lines, molecular markers, and therapies to investigate the key role of the BCL-2 family proteins in the survival of senescent cells. We first used BH3 profiling to assess changes in apoptotic priming upon senescence induction. Unexpectedly, not all cell types analyzed showed a decrease in apoptotic priming, BIM was downregulated, there was variability in BAX expression and BAK remained constant or increased. Therefore, there was not a clear pattern for pro-survival adaptation. Many studies have been devoted to find ways to eliminate senescent cells, leading to one of the most studied senolytic agents: navitoclax, a promiscuous BH3 mimetic that inhibits BCL-2, BCL-xL and BCL-W. While it is known that the BCL-2 family of proteins is commonly upregulated in senescent cells, the complexity of the apoptotic network has not been fully explored. Interestingly, we found distinct protein expression changes always leading to a BCL-xL mediated pro-survival adaptation, as assessed by BH3 profiling. When analyzing potential therapeutic strategies, we observed a stronger senolytic activity in these melanoma cell lines when specifically targeting BCL-xL using A-1331852, navitoclax or the PROTAC BCL-xL degrader DT2216. We found that the sensitizer protein HRK was systematically downregulated when senescence was induced, leading to an increased availability of BCL-xL. Furthermore, we identified that the main apoptotic inhibition was shaped by BCL-xL and BAK binding increase that prevented mitochondrial permeabilization and apoptosis. To our knowledge, this is the first time that the molecular basis for BCL-xL anti-apoptotic adaptation in senescence is described, paving the way for the development of new molecules that either prevent HRK downregulation or displace BCL-xL binding to BAK to be used as senolytics.

Senolytic treatment attenuates immune cell infiltration without improving IAV outcomes in aged mice

Aging is a major risk factor for poor outcomes following respiratory infections. In animal models, the most severe outcomes of respiratory infections in older hosts have been associated with an increased burden of senescent cells that accumulate over time with age and create a hyperinflammatory response. Although studies using coronavirus animal models have demonstrated that removal of senescent cells with senolytics, a class of drugs that selectively kills senescent cells, resulted in reduced lung damage and increased survival, little is known about the role that senescent cells play in the outcome of influenza A viral (IAV) infections in aged mice. Here, we tested if the aged mice survival or weight loss IAV infections could be improved using three different senolytic regimens. We found that neither dasatinib plus quercetin, fisetin, nor ABT-263 improved outcomes. Furthermore, both dasatanib plus quercetin and fisetin treatments further suppressed immune infiltration than aging alone. Additionally, our data show that the short-term senolytic agents do not reduce senescent markers in our aged mouse model. These findings suggest that acute senolytic treatments do not universally reverse aging related immune phenotype against all respiratory viral infections.

Effects of senotherapeutics on gut microbiome dysbiosis and intestinal inflammation in Crohn's disease: A pilot study

Inflammatory Bowel Disease (IBD) is characterized by chronic inflammation in the gastrointestinal tract, and is usually accompanied by dysbiosis in the gut microbiome, a factor that contributes to disease progression. Excessive production of reactive oxygen species (ROS) because of gut microbiome dysbiosis-one of the hallmark features of IBD-promotes chronic inflammation and facilitates the transformation of normal cells into senescent cells. Cellular senescence is associated with the development of various chronic and age-related diseases. We hypothesise that senolytic agents, specifically dasatinib (D) and quercetin (Q), could have a beneficial effect on both the gut microbiome and intestinal cells in IBD. The modulatory effects of a combination of D + Q was assessed in the M-SHIME model with faecal microbiota sourced from Crohn's disease patients. D + Q significantly modulated butyrate and lactate levels in the samples from specific patients. In addition, metabolomic analysis showed that D + Q positively impacted the abundance of anti-inflammatory bacteria while also significantly reducing the several species of pathogenic bacteria. Findings from a Caco-2 cell/THP1 co-culture model of IBD demonstrated that D + Q exerted strong immunomodulatory effects on the gut epithelium, evidenced by reduced NF-kB activity, and lower levels of the pro-inflammatory markers TNF-α, CXCL-10, and MCP-1. Furthermore, D + Q induced the secretion of anti-inflammatory cytokines, including IL-6 and IL-10. However, it should be noted that D + Q also led to the secretion of the pro-inflammatory cytokines IL-8. These findings suggest that D + Q could offer a novel therapeutic approach for advanced IBD management by modulating both the gut microbiome and inflammatory pathways. The results support the potential repurposing of senotherapeutic agents as a strategy for addressing the chronic inflammation central to IBD pathogenesis.

Dasatinib and Quercetin Limit Gingival Senescence, Inflammation, and Bone Loss

Cellular senescence has emerged as one of the central hallmarks of aging and drivers of chronic comorbidities, including periodontal diseases. Senescence can also occur in younger tissues and instigate metabolic alterations and dysfunction, culminating in accelerated aging and pathological consequences. Senotherapeutics, such as the combination of dasatinib and quercetin (DQ), are being increasingly used to improve the clinical outcomes of chronic disorders and promote a healthy life span through the reduction of senescent cell burden and senescence-associated secretory phenotype (SASP). Recent evidence suggests that senescent cells and SASP can contribute to the pathogenesis of periodontal diseases as well. In this study, we investigated the effect of DQ interventions on periodontal tissue health using preclinical models of aging. In vitro, DQ ameliorated biological signatures of senescence in human gingival keratinocytes upon persistent exposure to periodontal bacteria, Fusobacterium nucleatum, by modulating the levels of key senescence markers such as p16, SA-β-galactosidase, and lamin-B1 and inflammatory mediators associated with SASP including interleukin-8, matrix metalloproteinase (MMP)-1, and MMP-3. In vivo, the oral administration of DQ mitigated senescent cell burden and SASP in gingival tissues and reduced naturally progressing periodontal bone loss in aged mice. Collectively, our findings provide proof-of-concept evidence for translational studies and reveal that targeting gingival senescence and the senescence-associated secretome can be an effective strategy to improve periodontal health, particularly in vulnerable populations.

Senolytics: charting a new course or enhancing existing anti-tumor therapies?

Cell senescence is a natural response within our organisms. Initially, it was considered an effective anti-tumor mechanism. However, it is now believed that while cell senescence initially acts as a robust barrier against tumor initiation, the subsequent accumulation of senescent cells can paradoxically promote cancer recurrence and cause damage to neighboring tissues. This intricate balance between cell proliferation and senescence plays a pivotal role in maintaining tissue homeostasis. Moreover, senescence cells secrete many bioactive molecules collectively termed the senescence-associated secretory phenotype (SASP), which can induce chronic inflammation, alter tissue architecture, and promote tumorigenesis through paracrine signaling. Among the myriads of compounds, senotherapeutic drugs have emerged as exceptionally promising candidates in anticancer treatment. Their ability to selectively target senescent cells while sparing healthy tissues represents a paradigm shift in therapeutic intervention, offering new avenues for personalized oncology medicine. Senolytics have introduced new therapeutic possibilities by enabling the targeted removal of senescent cells. As standalone agents, they can clear tumor cells in a senescent state and, when combined with chemo- or radiotherapy, eliminate residual senescent cancer cells after treatment. This dual approach allows for the intentional use of lower-dose therapies or the removal of unintended senescent cells post-treatment. Additionally, by targeting non-cancerous senescent cells, senolytics may help reduce tumor formation risk, limit recurrence, and slow disease progression. This article examines the mechanisms of cellular senescence, its role in cancer treatment, and the importance of senotherapy, with particular attention to the therapeutic potential of senolytic drugs.

Transcriptomic signatures and network-based methods uncover new senescent cell anti-apoptotic pathways and senolytics

Cellular senescence is an irreversible cell cycle arrest caused by various stressors that damage cells. Over time, senescent cells accumulate and contribute to the progression of multiple age-related degenerative diseases. It is believed that these cells accumulate partly due to their ability to evade programmed cell death through the development and activation of survival and antiapoptotic resistance mechanisms; however, many aspects of how these survival mechanisms develop and activate are still unknown. By analyzing transcriptomic signature profiles generated by the LINCS L1000 project and using network-based methods, we identified various genes that could represent new senescence-related survival mechanisms. Additionally, employing the same methodology, we identified over 600 molecules with potential senolytic activity. Experimental validation of our computational findings confirmed the senolytic activity of Fluorouracil, whose activity would be mediated by a multitarget mechanism, revealing that its targets AURKA, EGFR, IRS1, SMAD4, and KRAS are new senescent cell antiapoptotic pathways (SCAPs). The development of these pathways could depend on the stimulus that induces cellular senescence. The SCAP development and activation mechanisms proposed in this work offer new insights into how senescent cells survive. Identifying new antiapoptotic resistance targets and drugs with potential senolytic activity paves the way for developing new pharmacological therapies to eliminate senescent cells selectively.

Enhancing immunity during ageing by targeting interactions within the tissue environment

Immunity declines with age. This results in a higher risk of age-related diseases, diminished ability to respond to new infections and reduced response to vaccines. The causes of this immune dysfunction are cellular senescence, which occurs in both lymphoid and non-lymphoid tissue, and chronic, low-grade inflammation known as 'inflammageing'. In this Review article, we highlight how the processes of inflammation and senescence drive each other, leading to loss of immune function. To break this cycle, therapies are needed that target the interactions between the altered tissue environment and the immune system instead of targeting each component alone. We discuss the relative merits and drawbacks of therapies that are directed at eliminating senescent cells (senolytics) and those that inhibit inflammation (senomorphics) in the context of tissue niches. Furthermore, we discuss therapeutic strategies designed to directly boost immune cell function and improve immune surveillance in tissues.

Targeting senescent hepatocytes for treatment of metabolic dysfunction-associated steatotic liver disease and multi-organ dysfunction

Senescent hepatocytes accumulate in metabolic dysfunction-associated steatotic liver disease (MASLD) and are linked to worse clinical outcomes. However, their heterogeneity and lack of specific markers have made them difficult to target therapeutically. Here, we define a senescent hepatocyte gene signature (SHGS) using in vitro and in vivo models and show that it tracks with MASLD progression/regression across mouse models and large human cohorts. Single-nucleus RNA-sequencing and functional studies reveal that SHGS+ hepatocytes originate from p21+ cells, lose key liver functions and release factors that drive disease progression. One such factor, GDF15, increases in circulation alongside SHGS+ burden and disease progression. Through chemical screening, we identify senolytics that selectively eliminate SHGS+ hepatocytes and improve MASLD in male mice. Notably, SHGS enrichment also correlates with dysfunction in other organs. These findings establish SHGS+ hepatocytes as key drivers of MASLD and highlight a potential therapeutic strategy for targeting senescent cells in liver disease and beyond.

Recent Advances in Aging and Immunosenescence: Mechanisms and Therapeutic Strategies

Cellular senescence is an irreversible state of cell cycle arrest. Senescent cells (SCs) accumulate in the body with age and secrete harmful substances known as the senescence-associated secretory phenotype (SASP), causing chronic inflammation; at the same time, chronic inflammation leads to a decrease in immune system function, known as immunosenescence, which further accelerates the aging process. Cellular senescence and immunosenescence are closely related to a variety of chronic diseases, including cardiovascular diseases, metabolic disorders, autoimmune diseases, and neurodegenerative diseases. Studying the mechanisms of cellular senescence and immunosenescence and developing targeted interventions are crucial for improving the immune function and quality of life of elderly people. Here, we review a series of recent studies focusing on the molecular mechanisms of cellular senescence and immunosenescence, the regulation of aging by the immune system, and the latest advances in basic and clinical research on senolytics. We summarize the cellular and animal models related to aging research, as well as the mechanisms, strategies, and future directions of aging interventions from an immunological perspective, with the hope of laying the foundation for developing novel and practical anti-aging therapies.

Targeting senescence in Amyotrophic Lateral Sclerosis: senolytic treatment improves neuromuscular function and preserves cortical excitability in a TDP-43Q331K mouse model

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder marked by progressive motor neuron degeneration in the primary motor cortex (PMC) and spinal cord. Aging is a key factor in ALS onset and progression, with evidence suggesting that biological aging-a process involving cellular decline- far outpaces chronological aging in ALS. This promotes senescent cell accumulation-marked by irreversible cell-cycle arrest, impaired apoptosis, and chronic inflammation-disrupting tissue homeostasis and impairing neuronal support functions. Thus, targeting senescence presents a novel therapeutic strategy for ALS. Here, we investigated the senolytic combination Dasatinib and Quercetin (D&Q) in TDP-43Q331K ALS mice. D&Q improved neuromuscular function and reduced plasma neurofilament light chain, a biomarker of axonal damage. The most pronounced improvement was the improved cortical excitability, accompanied by reductions in senescence and TDP-43 in the PMC. These findings highlight the potential of senolytics to mitigate ALS-related dysfunction, supporting their viability as a therapeutic strategy.

High-content screening identifies ganoderic acid A as a senotherapeutic to prevent cellular senescence and extend healthspan in preclinical models

Accumulated senescent cells during the aging process are a key driver of functional decline and age-related disorders. Here, we identify ganoderic acid A (GAA) as a potent anti-senescent compound with low toxicity and favorable drug properties through high-content screening. GAA, a major natural component of Ganoderma lucidum, possesses broad-spectrum geroprotective activity across various species. In C. elegans, GAA treatment extends lifespan and healthspan as effectively as rapamycin. Administration of GAA also mitigates the accumulation of senescent cells and physiological decline in multiple organs of irradiation-stimulated premature aging mice, natural aged mice, and western diet-induced obese mice. Notably, GAA displays a capability to enhance physical function and adapts to conditional changes in metabolic demand as mice aged. Mechanistically, GAA directly binds to TCOF1 to maintain ribosome homeostasis and thereby alleviate cellular senescence. These findings suggest a feasible senotherapeutic strategy for protecting against cellular senescence and age-related pathologies.

Inhibition of the metalloprotease ADAM19 as a novel senomorphic strategy to ameliorate gut permeability and senescence markers by modulating senescence-associated secretory phenotype (SASP)

Accumulation of DNA damage can accelerate aging through cellular senescence. Previously, we established a Drosophila model to investigate the effects of radiation-induced DNA damage on the intestine. In this model, we examined irradiation-responsive senescence in the fly intestine. Through an unbiased genome-wide association study (GWAS) utilizing 156 strains from the Drosophila Genetic Reference Panel (DGRP), we identified meltrin (the drosophila orthologue of mammalian ADAM19) as a potential modulator of the senescence-associated secretory phenotype (SASP). Knockdown of meltrin resulted in reduced gut permeability, DNA damage, and expression of the senescence marker β-galactosidase (SA-β-gal) in the fly gut following irradiation. Additionally, inhibition of ADAM19 in mice using batimastat-94 reduced gut permeability and inflammation in the gut. Our findings extend to human primary fibroblasts, where ADAM19 knockdown or pharmacological inhibition decreased expression of specific SASP factors and SA-β-gal. Furthermore, proteomics analysis of the secretory factor of senescent cells revealed a significant decrease in SASP factors associated with the ADAM19 cleavage site. These data suggest that ADAM19 inhibition could represent a novel senomorphic strategy.

The Regulation of Cellular Senescence in Cancer

Cellular senescence is a stable state of cell cycle arrest caused by telomere shortening or various stresses. After senescence, cells cease dividing and exhibit many age-related characteristics. Unlike the halted proliferation of senescence cells, cancer cells are considered to have unlimited growth potential. When cells display senescence-related features, such as telomere loss or stem cell failure, they can inhibit tumor development. Therefore, inducing cells to enter a senescence state can serve as a barrier to tumor cell development. However, many recent studies have found that sustained senescence of tumor cells or normal cells under certain circumstances can exert environment-dependent effects of tumor promotion and inhibition by producing various cytokines. In this review, we first introduce the causes and characteristics of induced cellular senescence, analyze the senescence process of immune cells and cancer cells, and then discuss the dual regulatory role of cell senescence on tumor growth and senescence-induced therapies targeting cancer cells. Finally, we discuss the role of senescence in tumor progression and treatment opportunities, and propose further studies on cellular senescence and cancer therapy.

Stone L, Haglund L. Senolytic treatment for low back pain

Senescent cells (SnCs) accumulate because of aging and external cellular stress throughout the body. They adopt a senescence-associated secretory phenotype (SASP) and release inflammatory and degenerative factors that actively contribute to age-related diseases, such as low back pain (LBP). The senolytics, o-vanillin and RG-7112, remove SnCs in human intervertebral discs (IVDs) and reduce SASP release, but it is unknown whether they can treat LBP. sparc-/- mice, with LBP, were treated orally with o-vanillin and RG-7112 as single or combination treatments. Treatment reduced LBP and SASP factor release and removed SnCs from the IVD and spinal cord. Treatment also lowered degeneration scores in the IVDs, improved vertebral bone quality, and reduced the expression of pain markers in the spinal cord. Together, our data suggest RG-7112 and o-vanillin as potential disease-modifying drugs for LBP and other painful disorders linked to cell senescence.

The role of retinal pigment epithelial senescence and the potential of senotherapeutics in age-related macular degeneration

Age-related macular degeneration (AMD) is a leading cause of visual impairment in the aging population. Evidence showing the presence of cellular senescence in retinal pigment epithelium (RPE) of patients with AMD is growing. Senescent RPE play a pivotal role in its pathogenesis. The senescent RPE suffers from structural and functional alterations and disruption of the surrounding microenvironment due to the development of the senescence-associated secretory phenotype, which contributes to metabolic dysfunctions and inflammatory responses in the retina. Senotherapeutics, including senolytics, senomorphics and others, are novel treatments targeting senescent cells and are promising treatments for AMD. As senotherapeutic targets are being developed, it is promising that the burden of AMD could be decreased.

Small extracellular vesicles from young adipose-derived stem cells ameliorate age-related changes in the heart of old mice

BACKGROUND

Aging entails a progressive decline in physiological functions, elevating the risk of age-related diseases like heart failure or aortic stenosis. Stem cell therapies, especially those that use paracrine signaling, can potentially mitigate the adverse effects of aging.

OBJECTIVES

The objective is to explore the potential of small extracellular vesicles (sEVs) derived from young adipose-derived stem cells (ADSC-sEVs) in reversing structural, molecular, and functional changes associated with aging in the heart.

METHODS

Aged C57BL/6J mice were treated intravenously with ADSC-sEVs from young mice or PBS as controls. Young mice were included to identify specific age-associated changes. The impact of sEV treatment on cardiac function was assessed using transthoracic echocardiography and physical endurance tests. Histological and molecular analyses were conducted on heart tissue to evaluate structural changes and markers of senescence, inflammation, and oxidative stress. A comprehensive metabolomic analysis was also performed on heart tissues to identify changes in metabolic profiles associated with aging and treatment status.

RESULTS

The administration of ADSC-sEVs significantly improves several aging-associated cardiac parameters, including oxidative stress, inflammation, and cellular senescence reductions. We also report on the age-related reversal of myocardial structure and function changes, highlighted by decreased fibrosis and improved vascularization. Notably, echocardiographic assessments reveal that sEV treatments ameliorate diastolic dysfunction and left ventricle structural alterations typically associated with aging. Furthermore, the treatment shifts the heart metabolome towards a more youthful profile.

CONCLUSIONS

These results denote the potential of ADSC-sEVs as a novel, noninvasive therapeutic strategy for mitigating cardiac aging-associated functional decline.

Combating chronic kidney disease-associated cachexia: A literature review of recent therapeutic approaches

In 2008, the Society on Sarcopenia, Cachexia, and Wasting Disorders introduced a generic definition for all types of cachexia: "a complex metabolic syndrome associated with the underlying illness characterized by a loss of muscle, with or without fat loss". It is well-known that the presence of inflammatory burden in end-stage renal disease (ESRD) patients may lead to the evolution of cachexia. Since the etiology of cachexia in chronic kidney disease (CKD) is multifactorial, thus the successful treatment must involve several concomitant measures (nutritional interventions, appetite stimulants, and anti-inflammatory pharmacologic agents) to provide integrated effective therapeutic modalities to combat causative factors and alleviate the outcomes of patients. Given the high mortality rate associated with cachexia, developing new therapeutic modalities are prerequisite for ameliorating patients with CKD worldwide. The present review aims to discuss some therapeutic strategies and provide an update on advances in nutritional approaches to counteract cachexia.

Immunosenescence promotes cancer development: from mechanisms to treatment strategies

The body's innate immune system plays a pivotal role in identifying and eliminating cancer cells. However, as the immune system ages, its functionality can deteriorate, becoming dysfunctional, inefficient, or even inactive-a condition referred to as immunosenescence. This decline significantly increases the risk of malignancies. While the pro-cancer effects of T-cell aging have been widely explored, there remains a notable gap in the literature regarding the impact of aging on innate immune cells, such as macrophages and neutrophils. This review seeks to address this gap, with emphasis on these cell types. Furthermore, although certain cancer immunotherapies, including immune checkpoint inhibitors (ICIs), have demonstrated efficacy across a broad spectrum of cancers, elderly patients are less likely to derive clinical benefit from these treatments. In some cases, they may even experience immune-related adverse events (irAEs). While senolytic strategies have shown promise in exerting anti-cancer effects, their adverse reactions and potential off-target effects present significant challenges. This review aims to elucidate the pro-cancer effects of immunosenescence, its implications for the efficacy and safety of ICIs, and potential anti-aging treatment strategies. In addition, optimizing anti-aging therapies to minimize adverse reactions and enhance therapeutic outcomes remains a critical focus for future research endeavors.

Senescent-like microglia limit remyelination through the senescence associated secretory phenotype

The capacity to regenerate myelin in the central nervous system diminishes with age. This decline is particularly evident in multiple sclerosis (MS), a chronic demyelinating disease. Whether cellular senescence, a hallmark of aging, contributes to remyelination impairment remains unknown. Here, we show that senescent cells accumulate within demyelinated lesions after injury, and treatments with senolytics enhances remyelination in young and middle-aged mice but not aged mice. In young mice, we observe the upregulation of senescence-associated transcripts, primarily in microglia and macrophages, after demyelination, followed by a reduction during remyelination. However, in aged mice, senescence-associated factors persist within lesions, correlating with inefficient remyelination. Proteomic analysis of the senescence-associated secretory phenotype (SASP) reveals elevated levels of CCL11/Eotaxin-1 in lesions of aged mice, which is found to inhibit oligodendrocyte maturation. These results suggest therapeutic targeting of SASP components, such as CCL11, may improve remyelination in aging and MS.

Circadian rhythm, hypoxia, and cellular senescence: From molecular mechanisms to targeted strategies

Cellular senescence precipitates a decline in physiological activities and metabolic functions, often accompanied by heightened inflammatory responses, diminished immune function, and impaired tissue and organ performance. Despite extensive research, the mechanisms underpinning cellular senescence remain incompletely elucidated. Emerging evidence implicates circadian rhythm and hypoxia as pivotal factors in cellular senescence. Circadian proteins are central to the molecular mechanism governing circadian rhythm, which regulates homeostasis throughout the body. These proteins mediate responses to hypoxic stress and influence the progression of cellular senescence, with protein Brain and muscle arnt-like 1 (BMAL1 or Arntl) playing a prominent role. Hypoxia-inducible factor-1α (HIF-1α), a key regulator of oxygen homeostasis within the cellular microenvironment, orchestrates the transcription of genes involved in various physiological processes. HIF-1α not only impacts normal circadian rhythm functions but also can induce or inhibit cellular senescence. Notably, HIF-1α may aberrantly interact with BMAL1, forming the HIF-1α-BMAL1 heterodimer, which can instigate multiple physiological dysfunctions. This heterodimer is hypothesized to modulate cellular senescence by affecting the molecular mechanism of circadian rhythm and hypoxia signaling pathways. In this review, we elucidate the intricate relationships among circadian rhythm, hypoxia, and cellular senescence. We synthesize diverse evidence to discuss their underlying mechanisms and identify novel therapeutic targets to address cellular senescence. Additionally, we discuss current challenges and suggest potential directions for future research. This work aims to deepen our understanding of the interplay between circadian rhythm, hypoxia, and cellular senescence, ultimately facilitating the development of therapeutic strategies for aging and related diseases.

Targeting senescent cells for the treatment of age-associated diseases

Cellular senescence, which entails cellular dysfunction and inflammatory factor release-the senescence-associated secretory phenotype (SASP)-is a key contributor to multiple disorders, diseases and the geriatric syndromes. Targeting senescent cells using senolytics has emerged as a promising therapeutic strategy for these conditions. Among senolytics, the combination of dasatinib and quercetin (D + Q) was the earliest and one of the most successful so far. D + Q delays, prevents, alleviates or treats multiple senescence-associated diseases and disorders with improvements in healthspan across various pre-clinical models. While early senolytic therapies have demonstrated promise, ongoing research is crucial to refine them and address such challenges as off-target effects. Recent advances in senolytics include new drugs and therapies that target senescent cells more effectively. The identification of senescence-associated antigens-cell surface molecules on senescent cells-pointed to another promising means for developing novel therapies and identifying biomarkers of senescent cell abundance.

Cellular senescence in the cancer microenvironment

In this ageing society, the number of patients suffering from age-related diseases, including cancer, is increasing. Cellular senescence is a cell fate that involves permanent cell cycle arrest. Accumulated senescent cells in tissues over time present senescence-associated secretory phenotype (SASP) and make the inflammatory context, disturbing the tumour microenvironment. In particular, the effect of senescent cancer-associated fibroblasts on cancer progression has recently come under the spotlight. Although scientific evidence on the impact of cellular senescence on cancer is emerging, the association between cellular senescence and cancer is heterogeneous and the comprehensive mechanism is still not revealed. Recently, a therapy targeting senescent cells, senotherapeutics, has been reported to be effective against cancer in preclinical research and even clinical trials. With further research, the development of senotherapeutics as a novel cancer therapy is expected.

Sex, senescence, senolytics, and cognition

This review focuses on sexual dimorphism in cellular senescence and senolytic treatment in relation to brain health and age-related cognitive decline. The stressors of aging, DNA damage, inflammation, and oxidative stress induce cell senescence, a hallmark of aging. Senescent cells change their function and molecular profile and are primed to release pro-inflammatory cytokines. The functional changes include the activation of cell signals to prevent cell death. The release of pro-inflammatory cytokines from peripheral senescent cells during middle age induces senescence of neighbor cells and heightens the level of systemic inflammation, contributing to neuroinflammation. In response to neuroinflammation and oxidative stress, some neurons alter their physiology, decreasing neuronal excitability and synaptic transmission. Senescent neurophysiology is protective against cell death due to excitotoxicity, at the expense of a loss of normal cell function, contributing to age-related cognitive decline. The level of peripheral cell senescence and systemic inflammation may underlie sexual dimorphism in the prevalence, symptoms, and pathogenesis of age-related diseases, including neurodegenerative diseases. Sex differences have been observed for senescence of astrocytes, microglia, and peripheral cells, including those involved in innate and adaptive immune responses. Interventions that remove senescent cells, such as senolytic drugs, can reduce or ameliorate some of the aging-related loss of function. Similarities and differences in senolytic responses of males and females depend on the system examined, the treatment regimen, the level of senescent cell burden, and the age when treatment is initiated. Estrogen impacts several of these factors and influences the transcription of genes promoting growth, proliferation, and cell survival programs in a manner opposite that of senolytic drugs. In addition, estrogen has anti-aging effects that are independent of cell senescence, including rapidly modifying senescent neurophysiology. Thus, it is important to recognize that, in addition to sex differences in cell senescence, there are other sexually dimorphic mechanisms that contribute to the aging process. The results indicate that senolytics interact with fundamental biology, including sex hormones.

Functional diversity of senescent cells in driving ageing phenotypes and facilitating tissue regeneration

As the global population continues to age, understanding the complex role of cellular senescence and its implications in healthy lifespans has gained increasing prominence. Cellular senescence is defined as the irreversible cessation of cell proliferation, accompanied by the secretion of a range of pro-inflammatory factors, collectively termed the senescence-associated secretory phenotype (SASP), in response to various cellular stresses. While the accumulation of senescent cells has been strongly implicated in the ageing process and the pathogenesis of age-related diseases owing to their pro-inflammatory properties, recent research has also highlighted their essential roles in processes such as tumour suppression, tissue development and repair. This review provides a comprehensive examination of the dual nature of senescent cells, evaluating their deleterious contributions to chronic inflammation, tissue dysfunction and disease, as well as their beneficial roles in maintaining physiological homeostasis. Additionally, we explored the therapeutic potential of senolytic agents designed to selectively eliminate detrimental senescent cells while considering the delicate balance between transient and beneficial senescence and the persistence of pathological senescence. A deeper understanding of these dynamics is critical to develop novel interventions aimed at mitigating age-related dysfunctions and enhancing healthy life expectancies.

The Role of Glial Cell Senescence in Alzheimer's Disease

Glial cell senescence, characterized by the irreversible arrest of cell division and a pro-inflammatory secretory phenotype, has emerged as a critical player in the pathogenesis of Alzheimer's disease (ad). While much attention has been devoted to the role of neurons in ad, growing evidence suggests that glial cells, including astrocytes, microglia, and oligodendrocytes, contribute significantly to disease progression through senescence. In this review, we explore the molecular mechanisms underlying glial cell senescence in ad, focusing on the cellular signaling pathways, including DNA damage response and the accumulation of senescence-associated secretory phenotypes (SASP). We also examine how senescent glial cells exacerbate neuroinflammation, disrupt synaptic function, and promote neuronal death in ad. Moreover, we discuss emerging therapeutic strategies aimed at targeting glial cell senescence to mitigate the neurodegenerative processes in ad. By providing a comprehensive overview of current research on glial cell senescence in Alzheimer's disease, this review highlights its potential as a novel therapeutic target in the fight against ad.

News from the old: Aging features in the intracardiac, musculoskeletal, and enteric nervous systems

Aging strongly affects the peripheral nervous system (PNS), triggering alterations that vary depending on the innervated tissue. The most frequent alteration in peripheral nerve aging is reduced nerve fiber and glial density which can lead to abnormal nerve functionality. Interestingly, the activation of a destructive phenotype takes place in macrophages across the PNS while a reduced number of neuronal bodies is a unique feature of some enteric ganglia. Single cell/nucleus RNA-sequencing has unveiled a striking complexity of cell populations in the peripheral nerves, and these refined cell type annotations could facilitate a better understanding of PNS aging. While the effects of senescence on individual PNS cell types requires further characterization, the use of senolytics appears to improve general PNS function in models of aging. Here, we review the current understanding of age-related changes of the intracardiac, musculoskeletal, and enteric nervous system sub-sections of the PNS, highlighting their commonalities and differences.

A BCL-xL/BCL-2 PROTAC effectively clears senescent cells in the liver and reduces MASH-driven hepatocellular carcinoma in mice

Accumulation of senescent cells (SnCs) plays a causative role in many age-related diseases and has also been implicated in the pathogenesis and progression of metabolic dysfunction-associated steatotic liver disease (MASLD). Senolytics that can selectively kill SnCs have the potential to be developed as therapeutics for these diseases. Here we report the finding that 753b, a dual BCL-xL/BCL-2 proteolysis-targeting chimera (PROTAC), acts as a potent and liver-tropic senolytic. We found that treatment with 753b selectively reduced SnCs in the liver in aged mice and STAM mice in part due to its sequestration in the liver. Moreover, 753b treatment could effectively reduce the progression of MASLD and the development of hepatocellular carcinoma (HCC) in STAM mice even after the mice developed substantial metabolic dysfunction-associated steatohepatitis (MASH) and hepatic fibrosis. These findings suggest that BCL-xL/BCL-2 PROTACs have the potential to be developed as therapeutics for MASLD to reduce MASH-driven HCC.

Targeting treatment resistance in cervical cancer: A new avenue for senolytic therapies

Cervical cancer poses a significant global health challenge, particularly impacting women in economically developing nations. This disparity stems from a combination of factors, including inadequate screening infrastructure and resource limitations. However, the foremost contributor is the widespread lack of awareness and limited accessibility to Human Papillomavirus (HPV) vaccination, which is a key preventative measure against cervical cancer development. Despite advancements in cervical cancer prevention, treatment resistance remains a major hurdle in achieving improved patient outcomes. Cellular senescence, specifically the senescence-associated secretory phenotype (SASP) and its bidirectional relationship with the immune system, has been implicated in resistance to conventional cervical cancer chemotherapy treatments. The exact mechanisms by which this state of growth arrest and the associated changes in immune regulation contribute to cervical cancer progression and the associated drug resistance are not entirely understood. This underscores the necessity for innovative strategies to address the prevalence of treatment-resistant cervical cancer, with one promising avenue being the utilisation of senolytics. Senolytics are agents that have promising efficacy in clearing senescent cells from tumour tissues, however neither the utilisation of senolytics for addressing senescence-induced treatment resistance nor the potential integration of immunotherapy as senolytic agents in cervical cancer treatment has been explored to date. This review provides a concise overview of the mechanisms underlying senescence induction and the pivotal role of the immune system in this process. Additionally, it explores various senolytic approaches that hold significant potential for advancing cervical cancer research.

New Horizons in Myotonic Dystrophy Type 1: Cellular Senescence as a Therapeutic Target

Myotonic dystrophy type 1 (DM1) is considered a progeroid disease (i.e., causing premature aging). This hypervariable disease affects multiple systems, such as the musculoskeletal, central nervous, gastrointestinal, and others. Despite advances in understanding the underlying pathogenic mechanism of DM1, numerous gaps persist in our understanding, hindering elucidation of the heterogeneity and severity of its symptoms. Accumulating evidence indicates that the toxic intracellular RNA accumulation associated with DM1 triggers cellular senescence. These cells are in a state of irreversible cell cycle arrest and secrete a cocktail of cytokines, referred to as a senescence-associated secretory phenotype (SASP), that can have harmful effects on neighboring cells and more broadly. We hypothesize that cellular senescence contributes to the pathophysiology of DM1, and clearance of senescent cells is a promising therapeutic approach for DM1. We will discuss the therapeutic potential of different senotherapeutic drugs, especially senolytics that eliminate senescent cells, and senomorphics that reduce SASP expression.

The efferocytosis process in aging: Supporting evidence, mechanisms, and therapeutic prospects for age-related diseases

BACKGROUND

Aging is characterized by an ongoing struggle between the buildup of damage caused by a combination of external and internal factors. Aging has different effects on phagocytes, including impaired efferocytosis. A deficiency in efferocytosis can cause chronic inflammation, aging, and several other clinical disorders.

AIM OF REVIEW

Our review underscores the possible feasibility and extensive scope of employing dual targets in various age-related diseases to reduce the occurrence and progression of age-related diseases, ultimately fostering healthy aging and increasing lifespan. Key scientific concepts of review Hence, the concurrent implementation of strategies aimed at augmenting efferocytic mechanisms and anti-aging treatments has the potential to serve as a potent intervention for extending the duration of a healthy lifespan. In this review, we comprehensively discuss the concept and physiological effects of efferocytosis. Subsequently, we investigated the association between efferocytosis and the hallmarks of aging. Finally, we discuss growing evidence regarding therapeutic interventions for age-related disorders, focusing on the physiological processes of aging and efferocytosis.

Aging, cellular senescence and Parkinson's disease

Parkinson's disease (PD) is the most common neurodegenerative movement disorder, affecting 1-2% of people over age 65. The risk of developing PD dramatically increases with advanced age, indicating that aging is likely a driving factor in PD neuropathogenesis. Several age-associated biological changes are also hallmarks of PD neuropathology, including mitochondrial dysfunction, oxidative stress, and neuroinflammation. Accumulation of senescent cells is an important feature of aging that contributes to age-related diseases. How age-related cellular senescence affects brain health and whether this phenomenon contributes to neuropathogenesis in PD is not yet fully understood. In this review, we highlight hallmarks of aging, including mitochondrial dysfunction, loss of proteostasis, genomic instability and telomere attrition in relation to well established PD neuropathological pathways. We then discuss the hallmarks of cellular senescence in the context of neuroscience and review studies that directly examine cellular senescence in PD. Studying senescence in PD presents challenges and holds promise for advancing our understanding of disease mechanisms, which could contribute to the development of effective disease-modifying therapeutics. Targeting senescent cells or modulating the senescence-associated secretory phenotype (SASP) in PD requires a comprehensive understanding of the complex relationship between PD pathogenesis and cellular senescence.

Senescence as a molecular target in skin aging and disease

Skin aging represents a multifactorial process influenced by both intrinsic and extrinsic factors, collectively known as the skin exposome. Cellular senescence, characterized by stable cell cycle arrest and secretion of pro-inflammatory molecules, has been implicated as a key driver of physiological and pathological skin aging. Increasing evidence points towards the role of senescence in a variety of dermatological diseases, where the accumulation of senescent cells in the epidermis and dermis exacerbates disease progression. Emerging therapeutic strategies such as senolytics and senomorphics offer promising avenues to target senescent cells and mitigate their deleterious effects, providing potential treatments for both skin aging and senescence-associated skin diseases. This review explores the molecular mechanisms of cellular senescence and its role in promoting age-related skin changes and pathologies, while compiling the observed effects of senotherapeutics in the skin and discussing the translational relevance.

Advances in biomarkers and diagnostic significance of organ aging

A complete understanding of aging is a critical first step in treating age-related diseases and postponing aging dysfunction in the context of an aging global population. Aging in organisms is driven by related molecular alterations that gradually occur in many organs. There has previously been a wealth of knowledge of how cells behave as they age, but when aging is investigated as a disease, the discovery and selection of aging biomarkers and how to diagnose the aging of the organism are crucial. Here, we provide a summary of the state of the field and suggest future potential routes for research on organ senescence markers. We reviewed research on biomarkers of risk of aging from the perspective of organ aging and summarized the biomarkers currently used on three scales. We emphasize that the combination of traditional markers with emerging multifaceted biomarkers may be a better way to diagnose age-related diseases.

Telomere Length of Cardiomyocytes in Wistar Rat Treated with Doxorubicin: In Vivo Experimental Study

The effect of doxorubicin on the relative telomere length of cardiomyocytes in Wistar rats was studied. Doxorubicin (2 mg/kg body weight) was injected into the caudal vein once a week for 4 weeks, the control group was injected with 0.9% NaCl solution in an equivalent volume. The serum concentrations of proinflammatory cytokines (MCP-1 and TNFα), oxidative stress marker 8-hydroxydeoxyguanosine (8-OHdG), and telomerase reverse transcriptase (TERT) were measured. In rats treated with doxorubicin, the relative length of cardiomyocyte telomeres and serum levels of 8-OHdG were higher than the in control. Thus, molecular effects of subchronic low-dose doxorubicin exposure in rats were revealed: telomeric regions of cardiomyocyte DNA were lengthened, and the level of oxidative stress marker increased.

A galactose-tethered tetraphenylethene prodrug mediated apoptosis of senescent cells for osteoporosis treatment

Osteoporosis and bone injury healing in elderly patients are major medical challenges, often exacerbated by the accumulation of senescent cells. Herein, we show that TPE-Gal, which contains a tetraphenylethene unit and a galactose moiety, offers a promising molecular therapy designed to light up and eliminate senescent cells through a hydrolysis reaction catalyzed by β-galactosidase, an enzyme overexpressed in senescent cells. The reaction produces TPE-OH, which, in turn, increases reactive oxygen species levels within the senescent cells, leading to noninflammatory apoptosis of senescent cells. This targeted clearance mechanism helps to alleviate osteoporosis symptoms and promotes bone injury healing. Moreover, apoptotic vesicles, which are generated during the process, are partly phagocytosed by macrophages, mimicking physiological metabolic processes. This study opens new avenues for addressing bone health issues through the designed bioclearance of senescent cells, aligning with the body's natural pathways for maintaining homeostasis.

Roadmap for alleviating the manifestations of ageing in the cardiovascular system

Ageing of the cardiovascular system is associated with frailty and various life-threatening diseases. As global populations grow older, age-related conditions increasingly determine healthspan and lifespan. The circulatory system not only supplies nutrients and oxygen to all tissues of the human body and removes by-products but also builds the largest interorgan communication network, thereby serving as a gatekeeper for healthy ageing. Therefore, elucidating organ-specific and cell-specific ageing mechanisms that compromise circulatory system functions could have the potential to prevent or ameliorate age-related cardiovascular diseases. In support of this concept, emerging evidence suggests that targeting the circulatory system might restore organ function. In this Roadmap, we delve into the organ-specific and cell-specific mechanisms that underlie ageing-related changes in the cardiovascular system. We raise unanswered questions regarding the optimal design of clinical trials, in which markers of biological ageing in humans could be assessed. We provide guidance for the development of gerotherapeutics, which will rely on the technological progress of the diagnostic toolbox to measure residual risk in elderly individuals. A major challenge in the quest to discover interventions that delay age-related conditions in humans is to identify molecular switches that can delay the onset of ageing changes. To overcome this roadblock, future clinical trials need to provide evidence that gerotherapeutics directly affect one or several hallmarks of ageing in such a manner as to delay, prevent, alleviate or treat age-associated dysfunction and diseases.

Exploring the link between fat-soluble vitamins and aging-associated immune system status: a literature review

The importance of vitamin D for a well-functioning immune system is becoming increasingly evident. Nevertheless, the other fat-soluble vitamins A, E and K also seem to play a central role regarding the adequate function of immune cells and to counteract excessive immune reactions and inflammatory processes. However, recognizing hidden hunger, particularly micronutrient deficiencies in vulnerable groups like the elderly, is crucial because older adults often lack sufficient micronutrients for various reasons. This review summarizes the latest findings on the immune modulating functions of fat-soluble vitamins in a physiological and pathophysiological context, provides a graphical comparison of the Recommended Daily Allowances between Deutschland, Austria, Confoederatio Helvetica (D-A-CH; eng. GSA, Germany, Switzerland, Austria), Deutsche Gesellschaft für Ernährung (DGE; eng. German Nutrition Society) and National Institutes of Health (NIH) across all age groups and, in particular, addresses the question regarding the benefits of supplementation of the respective micronutrients for the aging population of industrialized nations to strengthen the immune system. The following review highlights the importance of fat-soluble vitamins A, D, E and K which play critical roles in maintaining immune system function and, in some cases, in preventing excessive immune activation. Therefore, a better understanding of the relevance of adequate blood levels and consequently potential supplementation strategies may contribute to the prevention and management of infectious diseases as well as better overall health of the elderly.

Cellular Senescence in Health, Disease, and Lens Aging

Background: Cellular senescence is a state of irreversible cell cycle arrest that serves as a critical regulator of tissue homeostasis, aging, and disease. While transient senescence contributes to development, wound healing, and tumor suppression, chronic senescence drives inflammation, tissue dysfunction, and age-related pathologies, including cataracts. Lens epithelial cells (LECs), essential for maintaining lens transparency, are particularly vulnerable to oxidative stress-induced senescence, which accelerates lens aging and cataract formation. This review examines the dual role of senescence in LEC function and its implications for age-related cataractogenesis, alongside emerging senotherapeutic interventions. Methods: This review synthesizes findings on the molecular mechanisms of senescence, focusing on oxidative stress, mitochondrial dysfunction, and the senescence-associated secretory phenotype (SASP). It explores evidence linking LEC senescence to cataract formation, highlighting key studies on stress responses, DNA damage, and antioxidant defense. Recent advances in senotherapeutics, including senolytics and senomorphics, are analyzed for their potential to mitigate LEC senescence and delay cataract progression. Conclusions: LEC senescence is driven by oxidative damage, mitochondrial dysfunction, and impaired redox homeostasis. These factors activate senescence path-ways, including p53/p21 and p16/Rb, resulting in cell cycle arrest and SASP-mediated inflammation. The accumulation of senescent LECs reduces regenerative capacity, disrupts lens homeostasis, and contributes to cataractogenesis. Emerging senotherapeutics, such as dasatinib, quercetin, and metformin, show promise in reducing the senescent cell burden and modulating the SASP to preserve lens transparency.

Regulatory Network Inference of Induced Senescent Midbrain Cell Types Reveals Cell Type-Specific Senescence-Associated Transcriptional Regulators

Cellular senescence of brain cell types has become an increasingly important perspective for both aging and neurodegeneration, specifically in the context of Parkinson's Disease (PD). The characterization of classical hallmarks of senescence is a widely debated topic, whereby the context in which a senescence phenotype is being investigated, such as the cell type, the inducing stressor, and/or the model system, is an extremely important aspect to consider when defining a senescent cell. Here, we describe a cell type-specific profile of senescence through the investigation of various canonical senescence markers in five human midbrain cell lines using chronic 5-Bromodeoxyuridine (BrdU) treatment as a model of DNA damage-induced senescence. We used principal component analysis (PCA) and subsequent regulatory network inference to define both unique and common senescence profiles in the cell types investigated, as well as revealed senescence-associated transcriptional regulators (SATRs). Functional characterization of one of the identified regulators, transcription factor AP4 (TFAP4), further highlights the cell type-specificity of the expression of the various senescence hallmarks. Our data indicates that SATRs modulate cell type-specific profiles of induced senescence in key midbrain cell types that play an important role in the context of aging and PD.

Senescent cells as a target for anti-aging interventions: From senolytics to immune therapies

Aging and age-related diseases are major drivers of multimorbidity and mortality worldwide. Cellular senescence is a hallmark of aging. The accumulation of senescent cells is causally associated with pathogenesis of various age-associated disorders. Due to their promise for alleviating age-related disorders and extending healthspan, therapeutic strategies targeting senescent cells (senotherapies) as a means to combat aging have received much attention over the past decade. Among the conventionally used approaches, one is the usage of small-molecule compounds to specifically exhibit cytotoxicity toward senescent cells or inhibit deleterious effects of the senescence-associated secretory phenotype (SASP). Alternatively, there are immunotherapies directed at surface antigens specifically upregulated in senescent cells (seno-antigens), including chimeric antigen receptor (CAR) therapies and senolytic vaccines. This review gives an update of the current status in the discovery and development of senolytic therapies, and their translational progress from preclinical to clinical trials. We highlight the current challenges faced by senotherapeutic development in the context of senescence heterogeneity, with the aim of offering novel perspectives for future anti-aging interventions aimed at enhancing healthy longevity.

The immunosenescence clock: A new method for evaluating biological age and predicting mortality risk

Precisely assessing an individual's immune age is critical for developing targeted aging interventions. Although traditional methods for evaluating biological age, such as the use of cellular senescence markers and physiological indicators, have been widely applied, these methods inherently struggle to capture the full complexity of biological aging. We propose the concept of an 'immunosenescence clock' that evaluates immune system changes on the basis of changes in immune cell abundance and omics data (including transcriptome and proteome data), providing a complementary indicator for understanding age-related physiological transformations. Rather than claiming to definitively measure biological age, this approach can be divided into a biological age prediction clock and a mortality prediction clock. The main function of the biological age prediction clock is to reflect the physiological state through the transcriptome data of peripheral blood mononuclear cells (PBMCs), whereas the mortality prediction clock emphasizes the ability to identify people at high risk of mortality and disease. We hereby present nearly all of the immunosenescence clocks developed to date, as well as their functional differences. Critically, we explicitly acknowledge that no single diagnostic test can exhaustively capture the intricate changes associated with biological aging. Furthermore, as these biological functions are based on the acceleration or delay of immunosenescence, we also summarize the factors that accelerate immunosenescence and the methods for delaying it. A deep understanding of the regulatory mechanisms of immunosenescence can help establish more accurate immune-age models, providing support for personalized longevity interventions and improving quality of life in old age.

IL-23R is a senescence-linked circulating and tissue biomarker of aging

Cellular senescence is an aging mechanism characterized by cell cycle arrest and a senescence-associated secretory phenotype (SASP). Preclinical studies demonstrate that senolytic drugs, which target survival pathways in senescent cells, can counteract age-associated conditions that span several organs. The comparative efficacy of distinct senolytic drugs for modifying aging and senescence biomarkers in vivo has not been demonstrated. Here, we established aging- and senescence-related plasma proteins and tissue transcripts that changed in old versus young female and male mice. We investigated responsivity to acute treatment with venetoclax, navitoclax, fisetin or luteolin versus transgenic senescent cell clearance in aged p16-InkAttac mice. We discovered that age-dependent changes in plasma proteins, including IL-23R, CCL5 and CA13, were reversed by senotherapeutics, which corresponded to expression differences in tissues, particularly in the kidney. In plasma from humans across the lifespan, IL-23R increased with age. Our results reveal circulating factors as candidate mediators of senescence-associated interorgan signal transduction and translationally impactful biomarkers of systemic senescent cell burden.

Immune therapeutic strategies for the senescent tumor microenvironment

Senescent cells can either to promote immunosuppressive tumor microenvironment or facilitate immune surveillance. Despite the revolutionary impact of cancer immunotherapy, durable responses in solid tumors, particularly in advanced stages, remain limited. Recent studies have shed light on the influence of senescent status within the tumor microenvironment (TME) on therapy resistance and major efforts are needed to overcome these challenges. This review summarizes recent advancements in targeting cellular senescence, with a particular focus on immunomodulatory approaches on the hallmarks of cellular senescence.

The senotherapeutic potential of phytochemicals for age-related intestinal disease

During the last few decades, life expectancy has increased worldwide along with the prevalence of several age-related diseases. Among aging pathways, cellular senescence and chronic inflammation (or "inflammaging") appear to be connected to gut homeostasis and dysbiosis of the microbiome. Cellular senescence is a state of essentially irreversible cell cycle arrest that occurs in response to stress. Although senescent cells (SC) remain metabolically active, they do not proliferate and can secrete inflammatory and other factors comprising the senescence-associated secretory phenotype (SASP). Accumulation of SCs has been linked to onset of several age-related diseases, in the brain, bones, the gastrointestinal tract, and other organs and tissues. The gut microbiome undergoes substantial changes with aging and is tightly interconnected with either successful (healthy) aging or disease. Senotherapeutic drugs are compounds that can clear senescent cells or modulate the release of SASP factors and hence attenuate the impact of the senescence-associated pro-inflammatory state. Phytochemicals, phenolic compounds and terpenes, which have antioxidant and anti-inflammatory activities, could also be senotherapeutic given their ability to act upon senescence-linked cellular pathways. The aim of this review is to dissect links among the gut microbiome, cellular senescence, inflammaging, and disease, as well as to explore phytochemicals as potential senotherapeutics, focusing on their interactions with gut microbiota. Coordinated targeting of these inter-related processes might unveil new strategies for promoting healthy aging.