Cellular senescence: a key therapeutic target in aging and diseases

Immunosenescence in skeletal muscle: The role-play in cancer cachexia chessboard

With the increase in life expectancy, age-related conditions and diseases have become a widespread and relevant social burden. Among these, immunosenescence and cancer cachexia play a significant often intertwined role. Immunosenescence is the progressive aging decline of both the innate and adaptive immune systems leading to increased infection susceptibility, poor vaccination efficacy, autoimmune disease, and malignancies. Cancer cachexia affects elderly patients with cancer causing severe weight loss, muscle wasting, inflammation, and reduced response to therapies. Whereas the connections between immunosenescence and cancer cachexia have been raising attention, the molecular mechanisms still need to be completely elucidated. This review aims at providing the current knowledge about the interplay between immunosenescence, skeletal muscle, and cancer cachexia, analyzing the molecular pathways known so far to be involved. Finally, we highlight potential therapeutic strategies suited for elderly population aimed to block immunosenescence and to preserve muscle mass in cachexia, also presenting the analysis of the current state-of-the-art of related clinical trials.

Physical training reduces cell senescence and associated insulin resistance in skeletal muscle

BACKGROUND

Cell senescence (CS) is a key aging process that leads to irreversible cell cycle arrest and an altered secretory phenotype. In skeletal muscle (SkM), the accumulation of senescent cells contributes to sarcopenia. Despite exercise being a known intervention for maintaining SkM function and metabolic health, its effects on CS remain poorly understood.

OBJECTIVES

This study aimed to investigate the impact of exercise on CS in human SkM by analyzing muscle biopsies from young, normal-weight individuals and middle-aged individuals with obesity, both before and after exercise intervention.

METHODS

Muscle biopsies were collected from both groups before and after an exercise intervention. CS markers, insulin sensitivity (measured with euglycemic clamp), and satellite cell markers were analyzed. Additionally, in vitro experiments were conducted to evaluate the effects of cellular senescence on human satellite cells, focusing on key regulatory genes and insulin signaling.

RESULTS

Individuals with obesity showed significantly elevated CS markers, along with reduced expression of GLUT4 and PAX7, indicating impaired insulin action and regenerative potential. Exercise improved insulin sensitivity, reduced CS markers, and activated satellite cell response in both groups. In vitro experiments revealed that senescence downregulated key regulatory genes in satellite cells and impaired insulin signaling by reducing the Insulin Receptor β-subunit.

CONCLUSIONS

These findings highlight the role of CS in regulating insulin sensitivity in SkM and underscore the therapeutic potential of exercise in mitigating age- and obesity-related muscle dysfunction. Targeting CS through exercise or senolytic agents could offer a promising strategy for improving metabolic health and combating sarcopenia, particularly in at-risk populations.

Inhibiting the Histone Demethylase Kdm4a Restrains Cardiac Fibrosis After Myocardial Infarction by Promoting Autophagy in Premature Senescent Fibroblasts

Premature senescent fibroblasts (PSFs) play an important role in regulating the fibrotic process after myocardial infarction (MI), but their effect on cardiac fibrosis remains unknown. Here, the investigation is aimed to determine whether PSFs contribute to cardiac fibrosis and the underlying mechanisms involved. It is observed that premature senescence of fibroblasts is strongly activated in the injured myocardium at 7 days after MI and identified that Kdm4a is located in PSFs by the analysis of scRNA-seq data and immunostaining staining. Moreover, fibroblast specific gain- and loss-of-function assays showed that Kdm4a promoted the premature senescence of fibroblasts and cardiac interstitial fibrosis, contributing to cardiac remodeling in the advanced stage after MI, without influencing early cardiac rupture. ChIP-seq and ChIP-PCR revealed that Kdm4a deficiency promoted autophagy in PSFs by reducing Trim44 expression through increased levels of the H3K9me3 modification in the Trim44 promoter region. Furthermore, a coculture system revealed that Kdm4a overexpression increased the accumulation of PSFs and the secretion of senescence-associated secretory phenotype (SASP) factors, subsequently inducing cardiac fibrosis, which could be reversed by Trim44 interference. Kdm4a induces the premature senescence of fibroblasts through Trim44-mediated autophagy and then facilitates interstitial fibrosis after MI, ultimately resulting in cardiac remodeling, but not affecting ventricular rupture.

Attenuation of Cellular Senescence and Improvement of Osteogenic Differentiation Capacity of Human Liver Stem Cells Using Specific Senomorphic and Senolytic Agents

Expansion of adult stem cells in culture increases the percent of senescent cells, reduces their differentiation capacity and limits their clinical use. Here, we investigated whether treatment with certain senotherapeutic drugs would reduce the accumulation of senescent cells during expansion of human liver stem cells (HLSCs) while maintaining their differentiation capacity. Our results demonstrate that chronic treatment with the senomorphic XJB-5-131 or the senolytics cocktail D + Q reduced the number of senescent cells and significantly reduced the expression of senescence-associated genes and several inflammatory SASP factors in later passage HLSCs. Additionally, treatment with XJB-5-131 and D + Q improved the capacity of HLSCs to undergo osteogenic differentiation following extensive in vitro expansion. Overall, our data demonstrate that treatment with XJB-5-13 or D + Q results in a reduction in the percentage of replication-induced senescent HLSCs and likely other types of adult stem cells and improve the potential therapeutic use of later passage human stem cells.

Current strategies for senescence treatment: Focused on theranostic performance of nanomaterials

Age-related diseases imposed heavy burdens to the healthcare systems globally, while cell senescence served as one fundamental molecular/cellular basis for these diseases. How to tackle the senescence-relevant problems is a hotspot for biomedical research. In this review article, the hallmarks and molecular pathways of cell senescence were firstly discussed, followed by the introduction of the current anti-senescence strategies, including senolytics and senomorphics. With suitable physical or chemical properties, multiple types of nanomaterials were used successfully in senescence therapeutics, as well as senescence detection. Based on the accumulating knowledges for senescence, the rules of how to use these nanoplatforms more efficiently against senescence were also summarized, including but not limited to surface modification, material-cargo interactions, factor responsiveness etc. The comparison of these "senescence-selective" nanoplatforms to other treatment options (prodrugs, ADCs, PROTACs, CART etc.) was also given. Learning from the past, nanotechnology can add more choice for treating age-related diseases, and provide more (diagnostic) information to further our understanding of senescence process.

Exercise alleviates osteoporosis by regulating the secretion of the Senescent Associated Secretory Phenotype

As the elderly population grows, the number of patients with metabolic bone diseases such as osteoporosis has increased sharply, posing a significant threat to public health and social economics. Although pharmacological therapies for osteoporosis demonstrate therapeutic benefits, their prolonged use is associated with varying degrees of adverse effects. As a non-pharmacological intervention, exercise is widely recognized for its cost-effectiveness, safety, and lack of toxic side effects, making it a recommended treatment for osteoporosis prevention and management. Previous studies have demonstrated that exercise can improve metabolic bone diseases by modulating the Senescent Associated Secretory Phenotype (SASP). However, the mechanisms through which exercise influences SASP remain unclear. Therefore, this review aims to summarize the effects of exercise on SASP and elucidate the specific mechanisms by which exercise regulates SASP to alleviate osteoporosis, providing a theoretical basis for osteoporosis through exercise and developing targeted therapies.

Investigating the bidirectional interactions between senotherapeutic agents and human gut microbiota

Biological ageing is a time-dependent process that has implications for health and disease. Cellular senescence is a key driver in ageing and age-related diseases. Senotherapeutic agents have been shown to slow biological ageing by eliminating senescent mammalian cells. Given the increasing awareness of the gut microbiome in regulating human health, this study aimed to investigate the effects of senotherapeutic agents as pharmacological interventions on the human gut microbiota. In this study, the bidirectional effects of four senotherapeutic agents, quercetin, fisetin, dasatinib, and sirolimus, with the gut microbiota sourced from healthy human donors were investigated. The results revealed that quercetin was completely biotransformed by the gut microbiota within six hours, while dasatinib was the most stable of the four compounds. Additionally, metagenomic analysis confirmed that all four compounds increased the abundance of bacterial species associated with healthy ageing (e.g., Bacteroides fragilis, Bifidobacterium longum, and Veillonella parvula), and decreased the abundance of pathogenic bacteria primarily associated with age-related diseases (e.g., Enterococcus faecalis and Streptococcus spp.). The findings from this study provide a comprehensive understanding of the pharmacobiomics of senotherapeutic interventions, highlighting the potential of microbiome-targeted senolytics in promoting healthy ageing.

STAT3/TGFBI signaling promotes the temozolomide resistance of glioblastoma through upregulating glycolysis by inducing cellular senescence

Glioblastoma (GBM) is the most lethal type of brain tumor. Recent studies have indicated that cellular senescence-targeted therapy is a promising approach for cancer treatment. However, the underlying mechanisms remain to be clarified. In this study, 101 unique combinations of 10 machine learning algorithms were used to construct prognostic models based on cellular senescence-related genes (CSRGs). We developed the CSRG signature (CSRGS) using machine learning models that exhibited optimal performance. GBM samples were stratified into high- and low-CSRGS groups based on CSRGS scores. Patients in the high-CSRGS group exhibited a worse prognosis, higher immune infiltration, and increased sensitivity to immune checkpoint blockade therapy. Furthermore, senescence-related pathways were significantly correlated with glycolysis, indicating upregulated glycolytic metabolism in senescent GBM cells. We identified TGFBI as a key regulator that played vital roles in both glycolysis and cellular senescence in GBM. TGFBI was overexpressed in GBM samples compared to normal brain tissues, and its knockdown via shRNA inhibited cellular senescence, glycolysis, and temozolomide resistance. Chromatin immunoprecipitation (ChIP) and luciferase reporter assays confirmed that TGFBI is a direct STAT3 target and is required for the STAT3-induced promotion of cellular senescence, glycolysis, and drug resistance. The STAT3-TGFBI axis could be a potential target for senescence-targeted GBM therapy.

Unveiling the role of GATA4 in endothelial cell senescence and atherosclerosis development

BACKGROUND AND AIMS

Cellular senescence is intimately linked to atherosclerosis development and progression. However, the mechanism is not well known. GATA4 is a classical regulator in human fibroblast senescence. This study aimed to determine the role of GATA4 in endothelial cell (EC) senescence and atherosclerosis development and the mechanisms by which it acts.

METHODS

Senescence ECs were induced using H2O2 by isolating human primary umbilical vein ECs from umbilical veins. The level of GATA4 was examined in endothelial progenitor cells (EPCs), ECs of arterial tissue from older individuals (>65 years), and aged mice (>24 months). Adeno-associated virus with EC-selective Tie1 promoter, an EC-specific gene transduction system, was used to explore the role of GATA4 in EC senescence and atherosclerosis development in ApoE-/- mice. RT-qPCR, Western blot, ChIP-PCR, and ELISA were conducted to further explore the mechanism of GATA4 in EC senescence and atherosclerosis development.

RESULTS

GATA4 protein levels are elevated in EC senescence induced by H2O2 and EPCs in older individuals. Additionally, GATA4 protein levels are increased in the ECs of arterial tissue from older individuals and aged mice and are strongly correlated with the progression of atherosclerosis plaques. Knockdown of GATA4 decreased EC senescence, dysfunction, and monocyte adhesion. Mechanistically, we found that GATA4 activates NFκB2 transcription and induces senescence-associated secretory phenotype (SASP) expression (IL-6, IL-8, CXCL1, CXCL3, ICAM-1). In vivo experiments on ApoE-/- mice demonstrated that GATA4 overexpression in ECs contributes to higher SASP expression, vascular senescence, atherosclerotic plaque formation, and impaired cardiac function.

CONCLUSIONS

Taken together, our findings indicate that elevated EC GATA4 levels contribute to the progression of atherosclerosis through the GATA4-NFκB2-SASP pathway, suggesting potential therapeutic targets for atherosclerosis-related diseases.

Senescent brain cell types in Alzheimer's disease: Pathological mechanisms and therapeutic opportunities

Cellular senescence is a cell state triggered by programmed physiological processes or cellular stress responses. Stress-induced senescent cells often acquire pathogenic traits, including a toxic secretome and resistance to apoptosis. When pathogenic senescent cells form faster than they are cleared by the immune system, they accumulate in tissues throughout the body and contribute to age-related diseases, including neurodegeneration. This review highlights evidence of pathogenic senescent cells in the brain and their role in Alzheimer's disease (AD), the leading cause of dementia in older adults. We also discuss the progress and challenges of senotherapies, pharmacological strategies to clear senescent cells or mitigate their toxic effects, which hold promise as interventions for AD and related dementias (ADRD).

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.

Cellular senescence in tumor immune escape: Mechanisms, implications, and therapeutic potential

Cellular senescence, a hallmark of aging, has emerged as a captivating area of research in tumor immunology with profound implications for cancer prevention and treatment. In the tumor microenvironment, senescent cells exhibit a dual role, simultaneously hindering tumor development through collaboration with immune cells and evading immune cell attacks by upregulating immunoinhibitory proteins. However, the intricate immune escape mechanism of cellular senescence in the tumor microenvironment remains a subject of intense investigation. Chronic inflammation is exacerbated by cellular senescence through the upregulation of pro-inflammatory factors such as interleukin-1β, thereby augmenting the risk of tumorigenesis. Additionally, the interplay between autophagy and cellular senescence adds another layer of complexity. Autophagy, known to slow down the aging process by reducing p53/p21 levels, may be downregulated by cellular senescence. To harness the therapeutic potential of cellular senescence, targeting its immunological aspects has gained significant attention. Strategies such as immune checkpoint inhibitors and T-cell senescence inhibition are being explored in the context of cellular senescence immunotherapy. In this comprehensive review, we provide a compelling overview of the regulation of cellular senescence and delve into the influencing factors, including chronic inflammation, autophagy, and circadian rhythms, associated with senescence in the tumor microenvironment. We specifically focus on unraveling the enigmatic dual role of cellular senescence in tumor immune escape. By deciphering the intricate nature of cellular senescence in the tumor microenvironment, this review aims to advance our understanding and pave the way for leveraging senescence as a promising target for tumor immunotherapy applications.

Aging and Cancer-Inextricably Linked Across the Lifespan

Aging (as old man wind) alters the trajectory of cancer (dangerous seas) through changes in the immune system and metabolism (among many others), leading to altered cancer epidemiology, pathogenesis, and therapeutic responses, as represented by the research areas (boats)-artwork by Michael DeGregori.

Targeting IGF1-Induced Cellular Senescence to Rejuvenate Hair Follicle Aging

The insulin-like growth factor-1 (IGF-1) signaling pathway is known as a potent aging modifier, disruption of which consistently associates with lifespan extension across diverse species. Despite this established association, the mechanisms by which IGF-1 signaling modulates organ aging remain poorly understood. In this study, we assessed age-related changes in IGF-1 expression across multiple organs in mice and identified a more prominent increase in skin IGF-1 levels with aging-a phenomenon also observed in human skin. To explore the consequences of elevated IGF-1, we developed transgenic mice ectopically expressing human IGF-1 in the epidermis, driven by the bovine keratin 5 promoter (IGF-1 Tg). These mice exhibited premature aging of hair follicles, as evidenced by accelerated hair graying and loss. Single-cell RNA sequencing analyses of dorsal skin highlighted an upsurge in cellular senescence markers and the senescence-associated secretory phenotype (SASP) in hair follicle stem cells (HFSCs), alongside a decline in hair growth and HFSC exhaustion. Our findings indicate that excessive IGF-1 triggers HFSC senescence, thereby disrupting hair follicle homeostasis. Remarkably, interventions in IGF-1 signaling via downstream mechanisms-specifically blocking Ac-p53 activation via SIRT1 overexpression or senolytic treatment for senescent cell clearance, or reducing IGF-1 through dietary restriction-significantly reduced senescence markers, mitigated premature hair follicle aging phenotypes, and restored the stem cell pool. Our findings provide fundamental insights into the biological processes of hair aging and highlight the therapeutic promise of targeted interventions to rejuvenate aged HFSCs and promote hair follicle health.

Exploring TGF-β signaling in benign prostatic hyperplasia: from cellular senescence to fibrosis and therapeutic implications

As men get older, they often develop benign prostatic hyperplasia (BPH), an enlarged prostate that is not cancerous or dangerous. Although the etiology of BPH is unknown, increasing evidence indicates that the TGF-β signaling pathway might be a key player in its pathogenesis. TGF-β is a pleiotropic cytokine involved in proliferation, differentiation, and extracellular matrix re-modeling, which are all dysregulated in BPH. Cellular senescence is primarily initiated by TGF-β--induced, irreversible growth arrest and usually limits the prostate gland's hyperplastic growth. Moreover, senescent cells generate a Senescence-Associated Secretory Phenotype (SASP), which consists of numerous proinflammatory and profibrotic factors that can worsen disease ontogeny. In addition, TGF-β is among the most fibrogenic factors. At the same time, fibrosis involves a massive accumulation of extracellular matrix proteins, which can increase tissue stiffness and a loss of normal organ functions. TGF-β-mediated fibrosis in BPH changes the mechanical properties of the prostate and surrounding tissues to contribute to lower urinary tract symptoms. This review discusses the complicated molecular signaling of TGF-β underlying changes in cellular senescence and fibrosis during BPH concerning its therapeutic potential.

Exploring the Mechanisms of Testicular Aging: Advances in Biomarker Research

Aging biomarkers quantify aging progression and provide actionable targets for therapeutic interventions to mitigate age-related decline. This review synthesizes emerging evidence on testicular aging biomarkers, focusing on cellular senescence (Leydig, Sertoli, and endothelial cells), protein homeostasis disruption, mitochondrial dysfunction, germ stem cell depletion, sperm telomere length, epigenetic alterations, oxidative stress, inflammation, and gut microbiota dysbiosis. We propose that testicular aging serves as a critical nexus linking reproductive decline with systemic aging processes, with its pathological progression being quantifiable through specific biomarkers including the Leydig, Sertoli, and endothelial cells, INSL3, ribosomal protein RPL39L, sperm telomere length, relative telomere length mitochondrial translocator protein, and sialic acid. By bridging systemic aging paradigms with testis-specific mechanisms, we emphasize the urgency to identify organ-selective biomarkers for targeted interventions, advancing strategies to preserve male fertility and address population aging challenges.

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.

Takeda G protein-coupled receptor 5 (TGR5): an attractive therapeutic target for aging-related cardiovascular diseases

Aging is an independent risk factor for many chronic diseases, including cancer and cardiovascular, pulmonary, and neurodegenerative diseases. In recent years, the mechanisms of aging-related cardiovascular diseases (CVDs) have been studied intensively. Takeda G protein-coupled receptor 5 (TGR5) is a membrane receptor for bile acids that has been found to play an important role in various disease processes, such as inflammation, oxidative stress, and metabolic disorders, all of which contribute to aging-related CVDs. In this review, we summarise the role of TGR5 in aging-related CVDs and propose TGR5 as an attractive therapeutic target based on its mechanism of involvement, which may contribute to future drug target design.

GLSP mitigates vascular aging by promoting Sirt7-mediated Keap1 deacetylation and Keap1-Nrf2 dissociation

Background and Purpose: Vascular aging is a prior marker of human aging and a significant contributor to atherosclerosis and vascular calcification. However, there are limited pharmacological options available to mitigate vascular aging. Thus, understanding the mechanisms underlying vascular aging and age-related atherosclerosis and vascular calcification is crucial. This study investigates the targets of vascular aging and elucidates the role and mechanisms of Ganoderma lucidum spore powder (GLSP) in mitigating vascular aging and aging-associated atherosclerosis as well as vascular calcification. Methods: The anti-vascular aging effects of GLSP was determined in aged C57BL/6J mice and the targets of GLSP was identified through transcriptome sequencing. Additionally, the protective effects of GLSP on the aged vasculature were assessed by examining atherosclerosis in apoE-/- mice and vascular calcification in VD3 and nicotine-induced mice. In vitro, the protective effects of GLSP triterpenes against vascular aging and calcification was determined in vascular smooth muscle cells (VSMCs). Results: GLSP exerted anti-vascular aging effects by regulating the cell cycle and senescence-associated secretory phenotype (SASP), mitigating DNA damage, reducing oxidative stress, improving mitochondrial function and modulating metabolic levels. Furthermore, GLSP improved vascular aging-associated atherosclerosis and vascular calcification in vivo. Mechanistically, RNA sequencing revealed an upregulation of Sirt7 expression after GLSP treatment. Sirt7 inhibitor exacerbated VSMCs senescence and calcification in senescent VSMCs and abolished the anti-senescence and the inhibitory effect of GLSP triterpenes on VSMCs senescence and calcification. Innovatively, we found that Sirt7 interacted with Keap1 and facilitated Keap1 deacetylation, which promoted Keap1-Nrf2 dissociation and consequently enhanced Nrf2 nuclear translocation and activation. Conclusion: GLSP alleviates vascular aging by exerting antioxidant effects through the activation of the Sirt7-Nrf2 axis, providing a promising new strategy for delaying vascular aging, atherosclerosis and vascular calcification.

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.

Pathological and Inflammatory Consequences of Aging

Aging is a complex, progressive, and irreversible biological process that entails numerous structural and functional changes in the organism. These changes affect all bodily systems, reducing their ability to respond and adapt to the environment. Chronic inflammation is one of the key factors driving the development of age-related diseases, ultimately causing a substantial decline in the functional abilities of older individuals. This persistent inflammatory state (commonly known as "inflammaging") is characterized by elevated levels of pro-inflammatory cytokines, an increase in oxidative stress, and a perturbation of immune homeostasis. Several factors, including cellular senescence, contribute to this inflammatory milieu, thereby amplifying conditions such as cardiovascular disease, neurodegeneration, and metabolic disorders. Exploring the mechanisms of chronic inflammation in aging is essential for developing targeted interventions aimed at promoting healthy aging. This review explains the strong connection between aging and chronic inflammation, highlighting potential therapeutic approaches like pharmacological treatments, dietary strategies, and lifestyle changes.

Cellular Senescence Is a Central Driver of Cognitive Disparities in Aging

Cognitive function in aging is heterogeneous: while some older individuals develop significant impairments and dementia, others remain resilient and retain cognitive function throughout their lifespan. The molecular mechanisms that underlie these divergent cognitive trajectories, however, remain largely unresolved. Here, we utilized a high-resolution home-cage-based cognitive testing paradigm to delineate mechanisms that contribute to age-related cognitive heterogeneity. We cognitively stratified aged C57Bl/6N male mice by cognitive performance into intact (resilient) or impaired subgroups based on young performance benchmarks. Cognitively impaired males exhibited marked reactive gliosis in the hippocampus, characterized by microglial activation, increased astrocyte arborization, and elevated transcriptional expression of reactivity markers. These changes were accompanied by increased markers of cellular senescence and the associated senescence-associated secretory phenotype (SASP) in impaired animals, including p16INK4a, SASP factors (e.g., Il-6, Il-1b, Mmp3), and SA-β-gal staining in the hippocampus. Notably, clearance of senescent cells using senolytic agents dasatinib and quercetin ameliorated the heterogeneity in cognitive performance observed with age and attenuated impairment-associated gliosis, senescence markers, and mitochondrial dysfunction. Aged female mice could not be stratified into subgroups yet showed increased neuroinflammation with age that was not resolved with senolytics. Collectively, our findings implicate cellular senescence as a central driver of sex-specific neuroinflammation that drives divergent cognitive trajectories in aging. Thus, we demonstrate that senolytic treatment is an effective therapeutic strategy to mitigate cognitive impairment by reducing neuroinflammation and associated metabolic disturbances.

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.

Exosomal dynamics: Bridging the gap between cellular senescence and cancer therapy

Cancer remains one of the most devastating diseases, severely affecting public health and contributing to economic instability. Researchers worldwide are dedicated to developing effective therapeutics to target cancer cells. One promising strategy involves inducing cellular senescence, a complex state in which cells exit the cell cycle. Senescence has profound effects on both physiological and pathological processes, influencing cellular systems through secreted factors that affect surrounding and distant cells. Among these factors are exosomes, small extracellular vesicles that play crucial roles in cellular communication, development, and defense, and can contribute to pathological conditions. Recently, there has been increasing interest in engineering exosomes as precise drug delivery vehicles, capable of targeting specific cells or intracellular components. Studies have emphasized the significant role of exosomes from senescent cells in cancer progression and therapy. Notably, chemotherapeutic agents can alter the tumor microenvironment, induce senescence, and trigger immune responses through exosome-mediated cargo transfer. This review explores the intricate relationship between cellular senescence, exosomes, and cancer, examining how different therapeutics can eliminate cancer cells or promote drug resistance. It also investigates the molecular mechanisms and signaling pathways driving these processes, highlighting current challenges and proposing future perspectives to uncover new therapeutic strategies for cancer treatment.

Multifunctional hydrogel targeting senescence to accelerate diabetic wound healing through promoting angiogenesis

Diabetic wound healing remains a significant clinical challenge because of hyperglycaemia-induced cellular senescence, impaired angiogenesis, and chronic inflammation. To address these issues, we developed a multifunctional hydrogel (GelMA/PNS/Alg@IGF-1) that integrates gelatine methacryloyl (GelMA), Panax notoginseng saponins (PNS), and sodium alginate microspheres encapsulating insulin-like growth factor-1 (IGF-1). This hydrogel was engineered to achieve gradient and sustained release of bioactive agents to target senescence and promote vascular repair. In vitro studies demonstrated that the hydrogel significantly reduced oxidative stress, suppressed senescence markers and senescence-associated secretory phenotypes, and restored endothelial cell function under high-glucose conditions by inhibiting NF-κB pathway activation. Transcriptomic analysis revealed the modulation of pathways linked to inflammation, apoptosis, and angiogenesis. This hydrogel accelerated diabetic wound closure in a rat model in vivo and enhanced collagen deposition, granulation tissue formation, and neovascularization. Furthermore, the hydrogel mitigated oxidative stress and cellular senescence and promoted tissue remodelling. The synergistic effects of PNS and IGF-1 within the hydrogel established a pro-regenerative microenvironment to address both pathological ageing and vascular dysfunction. These findings highlight GelMA/PNS/Alg@IGF-1 as a promising therapeutic platform for diabetic wound management, as this material offers dual anti-senescence and proangiogenic efficacy to overcome the complexities of chronic wound healing.

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.

p53 enhances DNA repair and suppresses cytoplasmic chromatin fragments and inflammation in senescent cells

Genomic instability and inflammation are distinct hallmarks of aging, but the connection between them is poorly understood. Here we report a mechanism directly linking genomic instability and inflammation in senescent cells through a mitochondria-regulated molecular circuit involving p53 and cytoplasmic chromatin fragments (CCF) that are enriched for DNA damage signaling marker γH2A.X. We show that p53 suppresses CCF accumulation and its downstream inflammatory phenotype. p53 activation suppresses CCF formation linked to enhanced DNA repair and genome integrity. Activation of p53 in aged mice by pharmacological inhibition of MDM2 reverses transcriptomic signatures of aging and age-associated accumulation of monocytes and macrophages in liver. Mitochondrial ablation in senescent cells suppresses CCF formation and activates p53 in an ATM-dependent manner, suggesting that mitochondria-dependent formation of γH2A.X + CCF dampens nuclear DNA damage signaling and p53 activity. These data provide evidence for a mitochondria-regulated p53 signaling circuit in senescent cells that controls DNA repair, genome integrity, and senescence- and age-associated inflammation, with relevance to therapeutic targeting of age-associated disease.

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.

Caloric Restriction and Telomere Preservation in TERT Knockout Adipocyte Progenitors Does Not Rescue Mice From Metabolic Dysfunction due to a TERT Function in Adipocyte Mitochondria

Inactivation of telomerase (TERT) in adipocyte progenitor cells (APC) expedites telomere attrition, and the onset of diabetes in mice fed high-fat diet (HFD), which promotes APC over-proliferation and replicative senescence. Here, we show that time-restricted feeding or caloric restriction in the postnatal development of mice subsequently subjected to HFD prevents telomere attrition but not glucose intolerance. This metabolic effect of dietary intervention was not observed for mice with TERT KO in endothelial or myeloid cells. To characterize the telomere-independent effects of TERT in the APC lineage, we analyzed mice with TERT knockout in mature adipocytes (AD-TERT-KO), which do not proliferate and avoid telomere attrition. Analysis of adipocytes from AD-TERT-KO mice indicated reliance on glycolysis and decreased mitochondrial oxidative metabolism. We show that AD-TERT-KO mice have reduced cold tolerance and metabolism abnormality indicating a defect in adaptive thermogenesis, characteristic of aging. Conversely, ectopic TERT expression in brown adipocytes-induced mitochondrial oxidation and thermogenic gene expression. We conclude that TERT plays an important non-canonical function in the mitochondria of adipocytes.

STING in cancer immunoediting: Modeling tumor-immune dynamics throughout cancer development

Cancer immunoediting is a dynamic process of tumor-immune system interaction that plays a critical role in cancer development and progression. Recent studies have highlighted the importance of innate signaling pathways possessed by both cancer cells and immune cells in this process. The STING molecule, a pivotal innate immune signaling molecule, mediates DNA-triggered immune responses in both cancer cells and immune cells, modulating the anti-tumor immune response and shaping the efficacy of immunotherapy. Emerging evidence has shown that the activation of STING signaling has dual opposing effects in cancer progression, simultaneously provoking and restricting anti-tumor immunity, and participating in every phase of cancer immunoediting, including immune elimination, equilibrium, and escape. In this review, we elucidate the roles of STING in the process of cancer immunoediting and discuss the dichotomous effects of STING agonists in the cancer immunotherapy response or resistance. A profound understanding of the sophisticated roles of STING signaling pathway in cancer immunoediting would potentially inspire the development of novel cancer therapeutic approaches and overcome the undesirable protumor effects of STING activation.

The Ercc1-/Δ mouse model of XFE progeroid syndrome undergoes accelerated retinal degeneration

Age-related macular degeneration (AMD) is a major cause of vision loss in older adults. AMD is caused by degeneration in the macula of the retina. The retina is the highest oxygen consuming tissue in our body and is prone to oxidative damage. DNA damage is one hallmark of aging implicated in loss of organ function. Genome instability has been associated with several disorders that result in premature vision loss. We hypothesized that endogenous DNA damage plays a causal role in age-related retinal changes. To address this, we used a genetic model of systemic depletion of expression of the DNA repair enzyme ERCC1-XPF. The neural retina and retinal pigment epithelium (RPE) from Ercc1-/Δ mice, which models a human progeroid syndrome, were compared to age-matched wild-type (WT) and old WT mice. By 3-months-of age, Ercc1-/Δ mice presented abnormal optokinetic and electroretinogram responses consistent with photoreceptor dysfunction and visual impairment. Ercc1-/Δ mice shared many ocular characteristics with old WT mice including morphological changes, elevated DNA damage markers (γ-H2AX and 53BP1), and increased cellular senescence in the neural retinal and RPE, as well as pathological angiogenesis. The RPE is essential for the metabolic health of photoreceptors. The RPE from Ercc1-/Δ mice displayed mitochondrial dysfunction causing a compensatory glycolytic shift, a characteristic feature of aging RPE. Hence, our study suggests spontaneous endogenous DNA damage promotes the hallmarks of age-related retinal degeneration.

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.

The role of oxidative stress-mediated fibro-adipogenic progenitor senescence in skeletal muscle regeneration and repair

BACKGROUND

Stem cells play a pivotal role in tissue regeneration and repair. Skeletal muscle comprises two main stem cells: muscle stem cells (MuSCs) and fibro-adipogenic progenitors (FAPs). FAPs are essential for maintaining the regenerative milieu of muscle tissue and modulating the activation of muscle satellite cells. However, during acute skeletal muscle injury, the alterations and mechanisms of action of FAPs remain unclear.

METHODS

we employed the GEO database for bioinformatics analysis of skeletal muscle injury. A skeletal muscle injury model was established through cardiotoxin (CTX, 10µM, 50µL) injection into the tibialis anterior (TA) of C57BL/6 mice. Three days post-injury, we extracted the TA, isolated FAPs (CD31-CD45-PDGFRα+Sca-1+), and assessed the senescence phenotype through SA-β-Gal staining and Western blot. Additionally, we established a co-culture system to evaluate the capacity of FAPs to facilitate MuSCs differentiation. Finally, we alleviated the senescent of FAPs through in vitro (100 µM melatonin, 5 days) and in vivo (20 mg/kg/day melatonin, 15 days) administration experiments, confirming melatonin's pivotal role in the regeneration and repair processes of skeletal muscle.

RESULTS

In single-cell RNA sequencing analysis, we discovered the upregulation of senescence-related pathways in FAPs following injury. Immunofluorescence staining revealed the co-localization of FAPs and senescent markers in injured muscles. We established the CTX injury model and observed a reduction in the number of FAPs post-injury, accompanied by the manifestation of a senescent phenotype. Melatonin treatment was found to attenuate the injury-induced senescence of FAPs. Further co-culture experiments revealed that melatonin facilitated the restoration of FAPs' capacity to promote myoblast differentiation. Through GO and KEGG analysis, we found that the administration of melatonin led to the upregulation of AMPK pathway in FAPs, a pathway associated with antioxidant stress response. Finally, drug administration experiments corroborated that melatonin enhances skeletal muscle regeneration and repair by alleviating FAP senescence in vivo.

CONCLUSION

In this study, we first found FAPs underwent senescence and redox homeostasis imbalance after injury. Next, we utilized melatonin to enhance FAPs regenerative and repair capabilities by activating AMPK signaling pathway. Taken together, this work provides a novel theoretical foundation for treating skeletal muscle injury.

Delta Opioid Peptide [d-Ala2, d-Leu5]-Enkephalin Improves Physical and Cognitive Function and Increases Lifespan in Aged Female Mice

In this study, we explored the potential application of [d-Ala2, d-Leu5]-enkephalin (DADLE) in anti-ageing field in response to the trend of increasing global population ageing. We aimed to reveal experimentally whether DADLE can positively affect the lifespan and health of aged mammals through its unique anti-inflammatory or metabolic mechanisms. Forty-two female C57/BL6J mice aged 18 months were intraperitoneally injected with DADLE or normal saline for 2 months. Cognitive and motor functions were assessed using a water maze and treadmill stress test, respectively. The expressions of P16INK4A, Lamin B1 and sirtuin 1 were observed in the hippocampus and heart. The level of pro-inflammatory cytokines in the serum was measured by enzyme-linked immunosorbent assay. The telomere length of the mice was determined using the polymerase chain reaction method. Transcriptome analysis of 6-month-old female C57BL/6 J mice brains and hearts was assessed for body weight effects. Supplementation of exogenous DADLE to aged mice has demonstrated significant benefits, including improved motor function, enhanced cognitive performance and significantly extended lifespan. DADLE treatment resulted in a substantial increase in anti-ageing markers and a corresponding decrease in pro-ageing markers in the heart and brain of these mice. DADLE attenuated age-related inflammation, as evidenced by reductions in serum pro-inflammatory cytokines and inflammatory cell infiltration in tissues. Furthermore, DADLE supplementation significantly prolonged relative telomere length in aged female mice, suggesting a potential mechanism for its anti-ageing effects. Transcriptome analysis revealed that immune response and cellular signalling pathways are intricately involved in the protective effects of DADLE in aged mice, providing further insights into its mechanism of action. Inflammatory reaction may be improved by DADLE by regulating the infiltration of inflammatory cells in the liver and kidney and regulating the cognitive function of the brain and the ageing of the heart in mice.

Fifty-hertz magnetic fields induce DNA damage through activating mPTP associated mitochondrial permeability transition in senescent human fetal lung fibroblasts

With the rapid development and using of electromagnetic technology, artificial electromagnetic fields (EMFs) have become an emerging environmental factor in our daily life. Extremely-low-frequency (ELF) magnetic fields (MFs), generally generated by power lines and various electric equipment, is one of the most common EMFs in the environment which were concerned for the potential impact on human health. Base on limited evidence, ELF-MFs have been classified as possible carcinogen to human by International Agency for Research on Cancer (IARC), but the mechanisms have not been fully elucidated. Senescent cells are a group of special cells, characterized by cell cycle arrest, senescence-associated secretory phenotype (SASP), accumulation of macromolecular damage, and metabolic disturbance, play important role in fetal development, tissue aging, and even carcinogenesis. Thus, EMFs may promote carcinogenesis by affecting senescent cells, however, there are few studies. In this study, we found that exposure to 50 Hz MFs at 1.0 mT for 24 h could induce significant DNA damage in senescent but not non-senescent human fetal lung fibroblast suggested that senescent cells are more sensitive to 50 Hz MFs on DNA damage, and further results revealed that reactive oxygen species (ROS) generation mediated by mitochondrial permeability transition pore (mPTP) activation play critical role in this process. Our results indicated that cellular senescence can lead to cell sensitivity to the DNA damage effect of 50 Hz MFs, however, whether this play important role in mediating the carcinogenesis of EMFs await further study.

Methylmalonic acid at the serum level in the elderly contributes to cell growth via mitochondrial dysfunction in colorectal cancer cell spheroids

Methylmalonic acid (MMA) is a small molecule produced during the metabolism of propionate and branched-chain amino acids. Recently, it has been reported that the blood concentration of MMA increases with age and promotes lung cancer metastasis. However, little is known regarding its effects on cancers other than lung cancer. In the present study, we examined the effects of MMA on colorectal cancer cell spheroids. We found that MMA promoted the proliferation of colorectal cancer spheroids at physiological concentrations that can be exhibited by the elderly and induced mitochondrial reactive oxygen species generation, which in turn affected the promotion of cell growth. MMA treatment also induces a metabolic shift in the glycolytic system. These results suggest that MMA may promote cancer cell proliferation by decreasing mitochondrial function, inducing a metabolic shift, and provide new insights into the effects of aging on cancer.

The intersection of aging and estrogen in osteoarthritis

Osteoarthritis (OA) is a chronic joint disease characterized by cartilage degradation, inflammation, and pain. While multiple factors contribute to OA development, age and sex are primary risk factors, particularly affecting postmenopausal women. The dramatic increase in OA risk after menopause suggests estrogen deficiency accelerates disease progression. This review explores the molecular mechanisms connecting aging and estrogen deficiency in OA development, focusing on key genes and pathways identified through RNA sequencing.

Sauchinone Ameliorates Senescence Through Reducing Mitochondrial ROS Production

One of the major causes of senescence is oxidative stress caused by ROS, which is mainly generated from dysfunctional mitochondria. Strategies to limit mitochondrial ROS production are considered important for reversing senescence, but effective approaches to reduce them have not yet been developed. In this study, we screened the secondary metabolites that plants produce under oxidative stress and discovered sauchinone as a potential candidate. Sauchinone induced mitochondrial function recovery, enabling efficient electron transport within the electron transport chain (ETC). This led to a decrease in ROS production, a byproduct of inefficient electron transport. The reduction in ROS by sauchinone rejuvenated senescence-associated phenotypes. To understand the underlying mechanism by which sauchinone rejuvenates senescence, we carried out RNA sequencing and found VAMP8 as a key gene. VAMP8 was downregulated by sauchinone. Knockdown of VAMP8 decreased mitochondrial ROS levels and subsequently rejuvenated mitochondrial function, which was similar to the effect of sauchinone. Taken together, these studies revealed a novel mechanism by which sauchinone reduces mitochondrial ROS production by regulating mitochondrial function and VAMP8 expression. Our results open a new avenue for aging research to control senescence by regulating mitochondrial ROS production.

Mitochondrial Mutation Leads to Cardiomyocyte Hypertrophy by Disruption of Mitochondria-Associated ER Membrane

m.3243A>G is the most common pathogenic mtDNA mutation. High energy-demanding organs, such as heart, are usually involved in mitochondria diseases. However, whether and how m.3243A>G affects cardiomyocytes remain unknown. We have established patient-specific iPSCs carrying m.3243A>G and induced cardiac differentiation. Cardiomyocytes with high m.3243A>G burden exhibited hypertrophic phenotype. This point mutation is localised in MT-TL1 encoding tRNALeu (UUR). m.3243A>G altered tRNALeu (UUR) conformation and decreased its stability. mtDNA is essential for mitochondrial function. Mitochondria dysfunction occurred and tended to become round. Its interaction with ER, mitochondria-associated ER membrane (MAM), was disrupted with decreased contact number and length. MAM is a central hub for calcium trafficking. Disrupted MAM disturbed calcium homeostasis, which may be the direct and leading cause of cardiomyocyte hypertrophy, as MAM enforcement reversed this pathological state. Considering the threshold effect of mitochondrial disease, mito-TALENs were introduced to eliminate mutant mitochondria and release mutation load. Mutation reduction partially reversed the cellular behaviour and made it approach to that of control one. These findings reveal the pathogenesis underlying m.3243A>G from perspective of organelle interaction, rather than organelle. Beyond mitochondria quality control, its proper interaction with other organelles, such as ER, matters for mitochondria disease. This study may provide inspiration for mitochondria disease intervention.

Breast cancer: pathogenesis and treatments

Breast cancer, characterized by unique epidemiological patterns and significant heterogeneity, remains one of the leading causes of malignancy-related deaths in women. The increasingly nuanced molecular subtypes of breast cancer have enhanced the comprehension and precision treatment of this disease. The mechanisms of tumorigenesis and progression of breast cancer have been central to scientific research, with investigations spanning various perspectives such as tumor stemness, intra-tumoral microbiota, and circadian rhythms. Technological advancements, particularly those integrated with artificial intelligence, have significantly improved the accuracy of breast cancer detection and diagnosis. The emergence of novel therapeutic concepts and drugs represents a paradigm shift towards personalized medicine. Evidence suggests that optimal diagnosis and treatment models tailored to individual patient risk and expected subtypes are crucial, supporting the era of precision oncology for breast cancer. Despite the rapid advancements in oncology and the increasing emphasis on the clinical precision treatment of breast cancer, a comprehensive update and summary of the panoramic knowledge related to this disease are needed. In this review, we provide a thorough overview of the global status of breast cancer, including its epidemiology, risk factors, pathophysiology, and molecular subtyping. Additionally, we elaborate on the latest research into mechanisms contributing to breast cancer progression, emerging treatment strategies, and long-term patient management. This review offers valuable insights into the latest advancements in Breast Cancer Research, thereby facilitating future progress in both basic research and clinical application.

Glibenclamide targets MDH2 to relieve aging phenotypes through metabolism-regulated epigenetic modification

Mitochondrial metabolism-regulated epigenetic modification is a driving force of aging and a promising target for therapeutic intervention. Mitochondrial malate dehydrogenase (MDH2), an enzyme in the TCA cycle, was identified as an anti-aging target through activity-based protein profiling in present study. The expression level of MDH2 was positively correlated with the cellular senescence in Mdh2 knockdown or overexpression fibroblasts. Glibenclamide (Gli), a classic anti-glycemic drug, was found to inhibit the activity of MDH2 and relieve fibroblast senescence in an MDH2-dependent manner. The anti-aging effects of Gli were also further validated in vivo, as it extended the lifespan and reduced the frailty index of naturally aged mice. Liver specific Mdh2 knockdown eliminated Gli's beneficial effects in naturally aged mice, reducing p16INK4a expression and hepatic fibrosis. Mechanistically, MDH2 inhibition or knockdown disrupted central carbon metabolism, then enhanced the methionine cycle flux, and subsequently promoted histone methylation. Notably, the tri-methylation of H3K27, identified as a crucial methylation site in reversing cellular senescence, was significantly elevated in hepatic tissues of naturally aged mice with Mdh2 knockdown. Taken together, these findings reveal that MDH2 inhibition or knockdown delays the aging process through metabolic-epigenetic regulation. Our research not only identified MDH2 as a potential therapeutic target and Gli as a lead compound for anti-aging drug development, but also shed light on the intricate interplay of metabolism and epigenetic modifications in aging.

Cell enlargement modulated by GATA4 and YAP instructs the senescence-associated secretory phenotype

Dynamic changes in cell size are associated with development and pathological conditions, including aging. Although cell enlargement is a prominent morphological feature of cellular senescence, its functional implications are unknown; moreover, how senescent cells maintain their enlargement state is less understood. Here we show that an extensive remodeling of actin cytoskeleton is necessary for establishing senescence-associated cell enlargement and pro-inflammatory senescence-associated secretory phenotype (SASP). This remodeling is attributed to a balancing act between the SASP regulator GATA4 and the mechanosensor YAP on the expression of the Rho family of GTPase RHOU. Genetic or pharmacological interventions that reduce cell enlargement attenuate SASP with minimal effect on senescence growth arrest. Mechanistically, actin cytoskeleton remodeling couples cell enlargement to the nuclear localization of GATA4 and NF-κB via the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex. RhoU protein accumulates in mouse adipose tissue under senescence-inducing conditions. Furthermore, RHOU expression correlates with SASP expression in adipose tissue during human aging. Thus, our study highlights an unexpected instructive role of cell enlargement in modulating the SASP and reveals a mechanical branch in the senescence regulatory network.

Rejuvenation of Bone Marrow Mesenchymal Stem Cells: Mechanisms and Their Application in Senile Osteoporosis Treatment

Bone marrow mesenchymal stromal cells (BM-MSCs) are multipotent cells present in bone marrow; they play a crucial role in the process of bone formation. Cellular senescence is defined as a stable state of cell cycle arrest that impairs the functioning of cells. Research has shown that aging triggers a state of senescence in BM-MSCs, leading to a reduced capacity for osteogenic differentiation and the accumulation of senescent cells, which can accelerate the onset of various diseases. Therefore, it is essential to explore mechanisms and strategies for the rejuvenation of senescent BM-MSCs. Senile osteoporosis (SOP) is a metabolic bone disease characterized by reduced bone formation. The senescence of BM-MSCs is considered one of the most important factors in the occurrence and development of SOP. Therefore, the rejuvenation of BM-MSCs for the treatment of SOP represents a promising strategy. This work provides a summary of the functional alterations observed in senescent BM-MSCs and a systematic review of the mechanisms that facilitate the rejuvenation of senescent BM-MSCs. Additionally, we analyze the progress in and the limitations associated with the application of rejuvenated senescent BM-MSCs to treat SOP, with the aim of providing new insights for the prevention and treatment of SOP.

The Mechanism of Acupuncture Regulating Autophagy: Progress and Prospect

Autophagy plays a crucial role in the physiopathological mechanisms of diseases by regulating cellular functions and maintaining cellular homeostasis, which has garnered extensive attention from researchers worldwide. The holistic regulation and bidirectional regulation effects of acupuncture can modulate cellular autophagy, promoting or restoring the homeostasis of the body's internal environment to achieve therapeutic outcomes. This paper systematically reviews the research progress on the use of acupuncture for treating various diseases via the autophagy pathway, summarizes signal pathways related to acupuncture regulating autophagy, and analyzes the deficiencies present in the existing research. The review results indicate that the mechanism of action of acupuncture on autophagy dysfunction is reflected in the changes in LC3, Beclin1, p53, and autophagy-associated (ATG) protein expression, and regulates signaling pathways and key proteins or genes. The regulatory effect of acupuncture on autophagy capacity is bidirectional: it inhibits the abnormal activation of autophagy to prevent exacerbation of injury and reduce apoptosis, while also activating or enhancing autophagy to promote the elimination of inflammation and reduce oxidative stress. Further analysis suggests that the mechanisms of acupuncture regulating autophagy are insufficiently explored. Future research should prioritize the development of more appropriate animal models, analyzing the accuracy of relevant pathways and the specificity of indicators, exploring the synergistic effects among targets and signaling pathways, clarifying the regulatory mechanisms of acupuncture at various stages of autophagy, and evaluating the efficacy of acupuncture in autophagy modulating. This paper offers valuable insights into the regulation of autophagy by acupuncture.

Antioxidant Senotherapy by Natural Compounds: A Beneficial Partner in Cancer Treatment

Aging is a general biological process inherent in all living organisms. It is characterized by progressive cellular dysfunction. For many years, aging has been widely recognized as a highly effective mechanism for suppressing the progression of malignant neoplasms. However, in recent years, increasing evidence suggests a "double-edged" role of aging in cancer development. According to these data, aging is not only a tumor suppressor that leads to cell cycle arrest in neoplastic cells, but also a cancer promoter that ensures a chronic proinflammatory and immunosuppressive microenvironment. In this regard, in our review, we discuss recent data on the destructive role of senescent cells in the pathogenesis of cancer. We also identify for the first time correlations between the modulation of the senescence-associated secretory phenotype and the antitumor effects of naturally occurring molecules.

Oversecretion of CCL3 by Irradiation-Induced Senescent Osteocytes Mediates Bone Homeostasis Imbalance

Various stressors such as ionizing radiation (IR), chemotherapeutic agents, oxidative stress, and inflammatory responses can trigger the stress-induced premature senescence (SIPS) of cells in the bone microenvironment, including osteocytes. However, little is known about the mechanisms underlying the senescent cellular regulation of the differentiation potential and bone homeostasis. Here, we report a secretory change in senescent osteocytes activated by IR, its subsequent impact on osteogenic and osteoclastic differentiation, and the inflammatory cascade response. It was observed that osteocytes exhibited altered biological function, persistent and incomplete DNA damage repair, and characteristic senescence phenotypes after exposure to IR in vitro. Meanwhile, a concomitant increase in the CC chemokine ligand 3 (CCL3), a key component of the senescence-associated secretory phenotype (SASP), was observed in the IR-induced senescent osteocytes, which could further downregulate the osteogenic differentiation and enhance the osteoclastic differentiation in cell supernatant co-culture experiments. Notably, the enhancement of the PI3K/Akt/NF-κB signaling pathway in IR-induced senescent osteocytes appears to be an essential driver of the imbalance between the osteogenic and osteoclastic differentiation potentials. Taken together, these data suggest a novel role of CCL3 in IR-induced bone homeostatic imbalance through SASP cascade secretion, mediated by the PI3K/Akt/NF-κB signaling pathway.

The transcription factor STAT3 and aging: an intermediate medium

Aging is a physiological/pathological process accompanied by progressive impairment of cellular function, leading to a variety of aging-related diseases. STAT3 is one of the core regulatory factors of aging. It is involved in body metabolism, development and senescence, cell apoptosis and so on. During the aging process, the changes of growth factors and cytokines will cause the activation of STAT3 to varying degrees, regulate the inflammatory pathways related to aging, regulate body inflammation, mitochondrial function, cell aging and autophagy to regulate and influence the aging process. Drugs targeting STAT3 can treat senescence related diseases. This review summarizes the role of STAT3 signaling factors in the pathogenesis of aging, including mitochondrial function, cellular senescence, autophagy, and chronic inflammation mediated by inflammatory pathways. Finally, the key regulatory role of STAT3 in senescence related diseases is emphasized. In summary, we reveal that drug development and clinical application targeting STAT3 is one of the key points in delaying aging and treating aging-related diseases in the future.

Exosomal miR-302b rejuvenates aging mice by reversing the proliferative arrest of senescent cells

Cellular senescence, a hallmark of aging, involves a stable exit from the cell cycle. Senescent cells (SnCs) are closely associated with aging and aging-related disorders, making them potential targets for anti-aging interventions. In this study, we demonstrated that human embryonic stem cell-derived exosomes (hESC-Exos) reversed senescence by restoring the proliferative capacity of SnCs in vitro. In aging mice, hESC-Exos treatment remodeled the proliferative landscape of SnCs, leading to rejuvenation, as evidenced by extended lifespan, improved physical performance, and reduced aging markers. Ago2 Clip-seq analysis identified miR-302b enriched in hESC-Exos that specifically targeted the cell cycle inhibitors Cdkn1a and Ccng2. Furthermore, miR-302b treatment reversed the proliferative arrest of SnCs in vivo, resulting in rejuvenation without safety concerns over a 24-month observation period. These findings demonstrate that exosomal miR-302b has the potential to reverse cellular senescence, offering a promising approach to mitigate senescence-related pathologies and aging.

Senolytic Treatment Alleviates Corneal Allograft Rejection Through Upregulation of Angiotensin-Converting Enzyme 2 (ACE2)

Purpose

Allograft rejection remains a major cause of failure in high-risk corneal transplants, but the underlying mechanisms are not fully understood. This study aimed to investigate the contribution of transplantation stress-induced cellular senescence to corneal allograft rejection and to elucidate the associated molecular mechanisms.

Methods

Age-matched murine corneal transplantation models were established. Cellular senescence was evaluated using senescence-associated β-galactosidase (SA-β-Gal) staining, western blot, and immunofluorescence staining. The role of cellular senescence in corneal allograft rejection was analyzed using p16 knockout mice and adoptive transfer experiments. Senolytic treatment with ABT-263 was administered intraperitoneally to evaluate its effects on corneal allograft rejection. RNA sequencing and pharmacological approaches were employed to identify the underlying mechanisms.

Results

Surgical injury induced a senescence-like phenotype in both donor corneas and recipient corneal beds, characterized by an increased accumulation of SA-β-Gal-positive cells in the corneal endothelium and stroma and elevated expression of senescence markers p16 and p21. Using genetic and adoptive transfer models, transplantation stress-induced senescence was shown to exacerbate corneal allograft rejection. Importantly, clearance of senescent cells by ABT-263 significantly suppressed ocular alloresponses and immune rejection. Mechanistically, RNA sequencing and loss-of-function experiments demonstrated that the anti-rejection effects of senolytic treatment were closely dependent on angiotensin-converting enzyme 2 (ACE2).

Conclusions

These findings highlight transplantation stress-induced senescence as a pivotal pathogenic factor in corneal allograft rejection. Senolytic therapy emerges as a potential novel strategy to mitigate transplant rejection and improve corneal allograft survival.

Sonic hedgehog restrains the ubiquitin-dependent degradation of SP1 to inhibit neuronal/glial senescence associated phenotypes in chemotherapy-induced peripheral neuropathy via the TRIM25-CXCL13 axis

INTRODUCTION

Chemotherapy-induced peripheral neuropathy (CIPN) is a common complication that affects an increasing number of cancer survivors. However, the current treatment options for CIPN are limited. Paclitaxel (PTX) is a widely used chemotherapeutic drug that induces senescence in cancer cells. While previous studies have demonstrated that Sonic hedgehog (Shh) can counteract cellular dysfunction during aging, its role in CIPN remains unknown.

OBJECTIVES

Herein, the aim of this study was to investigate whether Shh activation could inhibits neuronal/glial senescence and alleviates CIPN.

METHODS

We treated ND7/23 neuronal cells and RSC96 Schwann cells with two selective Shh activators (purmorphamine [PUR] and smoothened agonist [SAG]) in the presence of PTX. Additionally, we utilized a CIPN mouse model induced by PTX injection. To assess cellular senescence, we performed a senescence-associated β-galactosidase (SA-β-gal) assay, measured reactive oxygen species (ROS) levels, and examined the expression of P16, P21, and γH2AX. To understand the underlying mechanisms, we conducted ubiquitin assays, LC-MS/MS, H&E staining, and assessed protein expression through Western blotting and immunofluorescence staining.

RESULTS

In vitro, we observed that Shh activation significantly alleviated the senescence-related decline in multiple functions included SA-β-gal activity, expression of P16 and P21, cell viability, and ROS accumulation in DRG sensory neurons and Schwann cells after PTX exposure. Furthermore, our in vivo experiments demonstrated that Shh activation significantly reduced axonal degeneration, demyelination, and improved nerve conduction. Mechanistically, we discovered that PTX reduced the protein level of SP1, which was ubiquitinated by the E3 ligase TRIM25 at the lysine 694 (K694), leading to increased CXCL13 expression, and we found that Shh activation inhibited PTX-induced neuronal/glial senescence and CIPN through the TRIM25-SP1-CXCL13 axis.

CONCLUSION

These findings provide evidence for the role of PTX-induced senescence in DRG sensory neurons and Schwann cells, suggesting that Shh could be a potential therapeutic target for CIPN.