Targeting cellular senescence with senotherapeutics: senolytics and senomorphics

Chrysophanol delays aging via insulin/IGF-1 signaling pathway

Aging is inevitable processes which play a significant role in the development of various diseases, including cardiovascular diseases, neurodegenerative disorders, and cancers. The extension of lifespan and the improvement of age-related diseases can potentially be achieved by targeting evolutionarily conserved pathways and mechanisms through pharmacological interventions. Chrysophanol (Chr), a naturally occurring anthraquinone compound primarily derived from rhubarb of the Polygonaceae family, exhibits a wide range of pharmacological activities, including anti-cancer, anti-inflammatory, and anti-bacterial effects. However, its role in regulating aging remains unclear. In this study, we discovered that Chr extends both lifespan and healthspan in Caenorhabditis elegans by activating the DAF-2/DAF-16 insulin signaling pathway. Furthermore, we observed that Chr promoted longevity in natural aging mice, doxorubicin-induced aging mice, and transgenic mice through the conserved Insulin/IGF-1 signaling pathway. Additionally, Chr also influenced senescence-associated secretory phenotypes (SASPs) and enhanced the expression of antioxidant genes, contributing to delayed aging. These findings highlight that Chr exerts anti-aging effects from C. elegans to mammals via the evolutionarily conserved Insulin/IGF-1 signaling pathway, positioning Chr as a promising candidate for the prevention and treatment of aging and age-related diseases.

Identification of Senomorphic miRNAs in Embryonic Progenitor and Adult Stem Cell-Derived Extracellular Vesicles

Extracellular vesicles (EVs) are secreted by most cell types, transmitting crucial signaling molecules like proteins, small RNAs, and DNA. We previously demonstrated that EVs from murine and human mesenchymal stem cells (MSCs) functioned as senomorphics to suppress markers of senescence and the inflammatory senescence-associated secretory phenotype (SASP) in cell culture and in aged mice. Here we demonstrate that EVs from additional types of human adult stem cells and embryonic progenitor cells have a senomorphic activity. Based on their miRNA profiles showing prevalence in stem cell EVs versus nonstem cell EVs and the number of age-related genes targeted, we identified eight miRNAs as potential senomorphic miRNAs. Analysis of these miRNAs by transfection into etoposide-induced senescent IMR90 human fibroblasts revealed that each of the miRNAs alone regulated specific senescence and SASP markers, but none had complete senomorphic activity. Evaluation of ~300 combinations of miRNAs for senotherapeutic activity identified a senomorphic cocktail of miR-181a-5p, miR-92a-3p, miR-21-5p, and miR-186-5p that markedly reduced the expression of p16INK4a, p21Cip1, IL-1β, and IL-6 and the percentage of SA-ß-gal-positive cells. Transcriptome analysis identified multiple pathways affected by the miRNA cocktail, including cellular senescence and inhibition of PCAF and HIPK2 in the p53 signaling pathway. Finally, treatment of aged mice with liposomes containing the four miRNA cocktail suppressed markers of senescence and inflammation in multiple tissues. These studies suggest that EVs derived from stem cells suppress senescence and inflammation, at least in part, through miRNAs and that a senomorphic miRNA cocktail could be used to target senescence and inflammation to extend health span.

H, Elsayed Ahmed R, Muralidharan P, Paulsamy P. SASP Modulation for Cellular Rejuvenation and Tissue Homeostasis: Therapeutic Strategies and Molecular Insights

Cellular senescence regulates aging, tissue maintenance, and disease progression through the Senescence-Associated Secretory Phenotype (SASP), a secretory profile of cytokines, chemokines, growth factors, and matrix-remodeling enzymes. While transient SASP aids wound healing, its chronic activation drives inflammation, fibrosis, and tumorigenesis. This review examines SASP's molecular regulation, dual roles in health and pathology, and therapeutic potential. The following two main strategies are explored: senescence clearance, which eliminates SASP-producing cells, and SASP modulation, which refines secretion to suppress inflammation while maintaining regenerative effects. Key pathways, including NF-κB, C/EBPβ, and cGAS-STING, are discussed alongside pharmacological, immunotherapeutic, gene-editing, and epigenetic interventions. SASP heterogeneity necessitates tissue-specific biomarkers for personalized therapies. Challenges include immune interactions, long-term safety, and ethical considerations. SASP modulation emerges as a promising strategy for aging, oncology, and tissue repair, with future advancements relying on multi-omics and AI-driven insights to optimize clinical outcomes.

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.

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.

ITGA1, the alpha 1 subunit of integrin receptor, is a novel marker of drug-resistant senescent melanoma cells in vitro

Chemotherapy-induced senescence may promote drug resistance and treatment failure. Precise detection and elimination of senescent cancer cells is considered as a novel promising anticancer strategy. However, data on senescence-associated skin cancer cell surface markers as potential therapeutic targets are limited. In the present study, we have established two models of drug-induced senescence in vitro using DNA damaging chemotherapeutics, namely etoposide (0.75-5 µM) and cisplatin (1.25-5 µM), and ten skin cancer cell lines, both melanoma (n = 8, A375, G-361, MM370, SH-4, SK-MEL-1, MeWo, MM127, RPMI-7951) and non-melanoma (n = 2, A431, MCC13), to investigate the levels of 97 cell surface markers. Initial gene expression analysis revealed the increasing tendency in the levels of seven transcripts (ITGA1, ITGA3, VAMP3, STX4, ARMCX3, ULBP2, and PLAUR) and five transcripts (ITGA1, ITGA3, STX4, ARMCX3, and PLAUR) in five etoposide and cisplatin-induced senescent melanoma cell lines, respectively, compared to corresponding proliferating cells. Elevated pools of integrin α1 (ITGA1) were confirmed at mRNA and protein levels in eight drug-induced senescent melanoma cell lines. Similar pattern of changes in integrin α1 levels was not observed in drug-induced senescent non-melanoma skin cancer cells. Analysis using clinical melanoma samples also showed that the levels of ITGA1 and ITGA3 were correlated with the presence of melanoma cells in a section. We document that integrin α1 can be considered as a novel marker of drug-induced senescent melanoma cells. Thus, we postulate that new integrin α1-based targeted therapies can be designed and tested against drug-induced senescent melanoma cells.

FOXOs and their roles in acute and chronic neurological disorders

The forkhead family of transcription factors of class O (FOXOs) consisting of four functionally related proteins, FOXO1, FOXO3, FOXO4, and FOXO6, are mammalian homologs of daf-16 in Caenorhabditis elegans and were previously identified as tumor suppressors, oxidative stress sensors, and cell survival modulators. Under normal physiological conditions, FOXO protein activities are negatively regulated by phosphorylation via the phosphoinositide 3-kinase (PI3K)-Akt pathway, a well-known cell survival pathway: Akt phosphorylates FOXOs to inactivate their transcriptional activity by relocalizing FOXOs from the nucleus to the cytoplasm for degradation. However, under oxidative stress or absent the cellular survival drive of growth factors, FOXO proteins translocate to the nucleus and upregulate a series of target genes, thereby promoting cell growth arrest and cell death and altering mitochondrial homeostasis. FOXO gene expression is also regulated by other transcriptional factors such as p53 or autoregulation by their activities and end products. Here we summarize the structure, posttranslational modifications, and translocation of FOXOs linking to their transcriptional control of cellular functions, survival, and death, emphasizing their role in regulating the cellular response to some acute insults and chronic neurological disorders. This review will conclude with a brief section on potential therapeutic interventions that can be used to modulate FOXOs' activities when treating acute and chronic neurological disorders.

ELN regulates cellular senescence: Emerging hypothesis for a non-canonical role

Elastic fibers are well-known extracellular matrix components that are essential for elastic properties and thus function of many tissues. Tropoelastin is encoded by the ELN gene which is the main component of the elastic fibers. Elastic fibers decrease with aging and this decrease is proposed to contribute to this process. Senescent cells, cells that stop to proliferate and that instruct their microenvironment, accumulate with aging and promote it. Until recently, whether ELN expression and function is linked to cellular senescence was unknown. Here we will comment and extend recent results supporting a function of the ELN gene in protecting cells from cellular senescence. We will also discuss hypotheses on mechanisms by which ELN could regulate cellular senescence, and especially a hypothesis that involves a non-canonical function of ELN regulating the mitochondrial respiratory chain activity, thereby controlling oxidative stress and cellular senescence. These findings provide critical insights into the molecular and cellular processes potentially underlying the phenotypes driven by ELN deletion in the context of aging.

The Role of Ginseng and Its Bioactive Compounds in Aging: Cells and Animal Studies

Aging is an inevitable process that is characterized by physiological deterioration and increased vulnerability to stressors. Therefore, the interest in hallmarks, mechanisms, and ways to delay or prevent aging has grown for decades. Natural plant products and their bioactive compounds have been studied as a promising strategy to overcome aging. Ginseng, a traditional herbal medicine, and its bioactive compound, the ginsenosides, have increasingly gained attention because of various pharmacological functions. This review introduces the species, useful parts, characteristics, and active components of ginseng. It primarily focuses on the bioconversion of ginsenosides through the unique steaming and drying process. More importantly, this review enumerates the antiaging mechanisms of ginseng, ginsenosides, and other bioactive compounds, highlighting their potential to extend the health span and mitigate age-related diseases based on twelve representative hallmarks of aging.

Cellular senescence offers distinct immunological vulnerabilities in cancer

Chronic damage following oncogene induction or cancer therapy can produce cellular senescence. Senescent cells not only exit the cell cycle but communicate damage signals to their environment that can trigger immune responses. Recent work has revealed that senescent tumor cells are highly immunogenic, leading to new ways to activate antitumor immunosurveillance and potentiate T cell-directed immunotherapies. However, other studies have determined that heterogeneous senescent stromal cell populations contribute to immunosuppression and tumor progression, sparking the development of senotherapeutics to target senescent cells that evade immune detection. We review current findings that provide deeper insights into the mechanisms contributing to the dichotomous role of senescence in immune modulation and how that can be leveraged for cancer immunotherapy.

Simvastatin ameliorates senescence-induced mitochondrial dysfunction in vascular smooth muscle cells

BACKGROUND AND AIMS

Senescence and mitochondrial dysfunction are two major indicators of aging. Mitochondria are potential drivers of aging phenotypes and dysfunctional mitochondria are associated with several age-related diseases. There is evidence that senescence induces changes in mitochondrial structure, dynamics, and function. Moreover, senescent vascular smooth muscle cells (VSMCs) are present in atherosclerotic plaques and contribute to their instability. The anti-atherosclerotic effects of simvastatin are well known, but recently other benefits, such as promoting mitochondrial quality and senostatic effects, have been hypothesized. We aimed to analyze simvastatin's senostatic effects in senescent VSMCs.

METHODS

We established and characterized mitochondrial dysfunction in doxorubicin-induced senescent VSMCs (doxorubicin) or VSMCs serially passaged to induce replicative senescence (old).

RESULTS

We observed in both senescent models few typical senescence markers such as altered cell morphology, cell cycle inhibitors, laminB1, an accumulation of dysfunctional mitochondria characterized by reduced mitochondrial membrane potential (MMP) and respiration, accumulation of reactive oxygen species (ROS), and an altered mitochondria morphology. Down-regulation of TFAM and TOM70 expression was observed only in old cells suggesting a reduction of mitochondrial biogenesis. Next, we investigated whether simvastatin could ameliorate age-associated phenotypes in senescent VSMCs. Simvastatin 0.1 μM reduces the senescence-associated secretory phenotype (SASP) and ROS production and improves mitochondrial respiration in doxorubicin and old VSMCs. Interestingly, the effects of simvastatin on mitochondrial respiration and SASP were replicated by using a siRNA for the hydroxy-methyl-glutaryl-coenzyme A (HMG-CoA) reductase, and abolished by adding mevalonic acid, suggesting that these effects are mediated through the inhibition of HMG-CoA reductase.

CONCLUSIONS

Our results suggest that simvastatin controls SASP and exerts potentially beneficial therapeutic effects by ameliorating senescence-induced mitochondrial dysfunction in senescent VSMCs.

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.

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.

Osalmid sensitizes clear cell renal cell carcinoma to navitoclax through a STAT3/BCL-XL pathway

Clear cell renal cell carcinoma (ccRCC) is a common and lethal urinary malignancy characterized by its resistance to apoptosis. Despite the emerging treatment options available for ccRCC, only a small proportion of patients achieve long-term survival benefits. Previous studies have demonstrated that inducing tumor cell senescence, followed by treatment using senolytics, represents a potential strategy for triggering tumor cell apoptosis. However, it remains unclear whether this strategy is suitable for the treatment of ccRCC. Using the whole-genome CRISPR screening database Dependency Map portal (DepMap), we identified ribonucleotide reductase family member 2 (RRM2), which catalyzes the conversion of ribonucleotides to deoxyribonucleotides (dNTPs), as an essential targetable gene for ccRCC. Herein, we report that the combination of the choleretic drug osalmid targeting RRM2 and the senolytic compound navitoclax targeting BCL-XL represents a novel therapeutic approach for ccRCC. Furthermore, we have validated this approach across a panel of human ccRCC cells with different genetic backgrounds and multiple preclinical models, including cell line-derived xenografts (CDX), patient-derived xenografts (PDX), and patient-derived organoids (PDO). Mechanistically, osalmid-mediated inhibition of dNTPs generation induces cellular senescence in ccRCC, concomitant with STAT3 activation and upregulation of BCL-XL, thus rendering these cells vulnerable to navitoclax, which targets the BCL-2 protein family.

A Ruthenium(II) Complex Inhibits BRD4 for Synergistic Seno- and Chemo-Immunotherapy in Cisplatin-Resistant Tumor Cells

Drug resistance is a significant challenge for tumor therapy. Activating immunity is an effective method to combat drug-resistant tumors. Utilizing metallic chemotherapeutic agents to induce nonapoptotic programmed cell death is a practical approach to stimulate immunity. Besides, triggering tumor cell senescence, named senotherapy, is also an effective but often ignored method to induce immune responses. Despite some progress, reports on metallic immunotherapeutic stimuli are sparse and mainly delve into the level of organelle targeting, with vague drug-target mechanisms. Here, we report a Ru(II) complex (Ru2c) inhibits BRD4 with high affinity at a nanomolar constant. After encapsulation into biotin-DNA cage, Ru2c@biotin-DNA cage was demonstrated to kill drug-resistant cancer cells through a synergistic apoptosis-ferroptosis-senescence pathway, exhibiting 51-fold anticancer activity compared to the commercial inhibitor JQ-1. Ru2c effectively erased drug-resistant tumors and activated innate and acquired immunity in vivo. To the best of our knowledge, Ru2c is the first metal-based BRD4 inhibitor to achieve synergistic seno-immunotherapy and chemo-immunotherapy.

Apoptotic and senolytic effects of hERG/Eag1 channel blockers in combination with temozolomide in human glioblastoma cells

Temozolomide (TMZ) concomitant with radiotherapy is the first-line treatment for glioblastoma. However, treatment resistance is frequently observed in patients. Cellular senescence (CSEN) induced by TMZ has been proposed to be one underlying mechanism resulting in resting cells, causing inflammation and possibly recurrences if senescent cells re-enter the cell cycle after treatment. Inhibition of the K+ channels human ether-à-go-go type 1 (Eag1) and human ether-à-go-go-related gene (hERG) has shown promising effects in several tumor types including glioblastoma through growth inhibition and induction of apoptosis. In the present study, we analyzed the impact of hERG/Eag1 inhibition on apoptosis and CSEN on its own and in combination with TMZ in a panel of human glioblastoma cell lines and primary glioblastoma cells. hERG/Eag1 protein expression was determined by Western blotting and immunocytochemistry. Cytotoxicity of astemizole and terfenadine alone or in combination with TMZ was assessed by MTT assays. Apoptotic yields were determined by Annexin V/propidium iodide staining, and CSEN was quantified by determining SA-β-galactosidase levels through flow cytometry. We observed a similar protein expression of hERG and Eag1 in all glioblastoma cell lines and primary glioblastoma cells. Astemizole and terfenadine were cytotoxic in glioblastoma cells at low micromolar concentrations (5-10 µM range) through induction of apoptosis. In combination with TMZ, both drugs synergistically sensitized glioblastoma cells to TMZ-induced apoptosis. Moreover, astemizole reduced significantly the TMZ-induced CSEN level, indicating its impact on CSEN induction. Here, we show for the first time that blocking hERG/Eag1 channels in glioblastoma cells can relief TMZ-induced CSEN and synergistically ameliorates cytotoxicity through the induction of apoptosis.

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.

Immunosenescence in autoimmune diseases

Autoimmune diseases (AIDs) are a group of disorders in which the immune system mistakenly attacks the body's own tissues, characterized by the loss of tolerance to self-antigens and destruction of tissues. Aging is a natural process of physiological decline that also alters the immune system, a condition known as immunosenescence. During immunosenescence, the immune system undergoes various changes, including modifications and antigenicity of self-antigens, abnormalities in the quantity, phenotype, and function of lymphocytes and antibodies, as well as a narrowing of the B and T cell receptor repertoire, changes that may increase susceptibility to AIDs. Additionally, senescent immune cells and the senescence-associated secretory phenotype (SASP) contribute to target organ involvement in AIDs, exacerbating chronic inflammation and tissue damage. Mitochondrial dysfunction and metabolic imbalances in AIDs lead to the accumulation of senescent cells, which act as upstream drivers of immunosenescence. In this review, we summarize the bidirectional relationship between AIDs and immunosenescence, as well as its potential mechanisms. Therapeutic approaches targeting immunosenescence in AIDs remain at an early stage. Strategies aimed at resetting or reversing the aging immune system are expected to become a novel direction in the future.

The role of VEGF in vascular dementia: impact of aging and cellular senescence

Vascular Endothelial Growth Factor (VEGF) is a critical element in vascular dementia (VD) pathogenesis and therapeutic development while remaining strongly influenced by aging processes and cellular aging mechanisms. VEGF's multiple effects comprise neuroprotective functions, its role in vascular development, and its ability to regulate brain blood flow systems, all leading to cognitive preservation. The prefrontal cortex exhibits elevated VEGF gene levels, which directly matches the advancement of cognitive deficits in patients with Alzheimer's disease and VD. These patients exhibit higher VEGF levels in their CSF fluid, demonstrating that disease pathology includes multiple inseparable factors. Aging dramatically worsens VEGF regulation because endothelial dysfunction combines with chronic inflammation and oxidative stress to generate adverse vascular symptoms that include atherosclerosis and stroke. Cellular senescence convolutes these processes by causing damaging inflammatory reactions alongside impaired vascular healing abilities. The secretion of pro-inflammatory cytokines from senescent cells (SCs) disrupts VEGF signaling and produces harmful consequences for both vascular health and cognitive well-being. The neuroprotective properties of VEGF-A165a and VEGF-A165b variants demonstrate their ability to lessen β-amyloid and tau protein toxicity. The protective mechanisms of VEGF depend heavily on VEGF expression levels and receptor functionality, both of which decrease with aging. The combination of approaches that modulate VEGF signaling and SC accumulation shows potential for designing treatments against VD. People can sustain BBB functionality over a longer period through Mediterranean diet consumption together with aerobic exercise along with developing therapies, including senolytics and senomorphics, which delay neurodegenerative progression. Future investigative efforts must improve VEGF delivery methods while studying cellular senescence mechanisms and developing advanced methods to detect SC cells. A three-dimensional healthcare approach combining VEGF-targeted treatments with anti-ageing interventions and detailed diagnostic techniques shows the potential for effective VD management to achieve better patient results.

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.

Design principles of gene circuits for longevity

Aging is a dynamic process that is driven by cellular damage and disruption of homeostatic gene regulatory networks (GRNs). Traditional studies often focus on individual genes, but understanding their interplay is key to unraveling the mechanisms of aging. This review explores the gene circuits that influence longevity and highlights the role of feedback loops in maintaining cellular balance. The SIR2-HAP circuit in yeast serves as a model to explore how mutual inhibition between pathways influences aging trajectories and how engineering stable fixed points or oscillations within these circuits can extend lifespan. Feedback loops crucial for maintaining homeostasis are also reviewed, and we highlight how their destabilization accelerates aging. By leveraging systems and synthetic biology, strategies are proposed that may stabilize these loops within single cells, thereby enhancing their resilience to aging-related damage.

The Common Hallmarks and Interconnected Pathways of Aging, Circadian Rhythms, and Cancer: Implications for Therapeutic Strategies

The intricate relationship between cancer, circadian rhythms, and aging is increasingly recognized as a critical factor in understanding the mechanisms underlying tumorigenesis and cancer progression. Aging is a well-established primary risk factor for cancer, while disruptions in circadian rhythms are intricately associated with the tumorigenesis and progression of various tumors. Moreover, aging itself disrupts circadian rhythms, leading to physiological changes that may accelerate cancer development. Despite these connections, the specific interplay between these processes and their collective impact on cancer remains inadequately explored in the literature. In this review, we systematically explore the physiological mechanisms of circadian rhythms and their influence on cancer development. We discuss how core circadian genes impact tumor risk and prognosis, highlighting the shared hallmarks of cancer and aging such as genomic instability, cellular senescence, and chronic inflammation. Furthermore, we examine the interplay between circadian rhythms and aging, focusing on how this crosstalk contributes to tumorigenesis, tumor proliferation, and apoptosis, as well as the impact on cellular metabolism and genomic stability. By elucidating the common pathways linking aging, circadian rhythms, and cancer, this review provides new insights into the pathophysiology of cancer and identifies potential therapeutic strategies. We propose that targeting the circadian regulation of cancer hallmarks could pave the way for novel treatments, including chronotherapy and antiaging interventions, which may offer important benefits in the clinical management of cancer.

Exploring Lymph Node Stroma Ageing: Immune Implications and Future Directions

Ageing is an inevitable biological process that impacts the immune system, leading to immunosenescence and inflammaging, which contribute to increased susceptibility to infections, autoimmune diseases and cancers in individuals over the age of 65. This review focuses on the ageing of lymph node stromal cells (LNSCs), which are crucial for maintaining lymph node (LN) structure and function. Age-related changes in LNs, such as fibrosis and lipomatosis, disrupt the LN architecture and reduce immune cell recruitment and function, impairing immune responses to infections and vaccinations. The review discusses the structural and functional decline of various LNSC subsets, including fibroblastic reticular cells (FRCs), lymphatic endothelial cells (LECs) and blood endothelial cells (BECs), highlighting their roles in immune cell activation and homeostasis. Potential strategies to restore aged LNSC function, such as enhancing LNSC activation during vaccination and using senotherapeutics, are explored. Outstanding questions regarding the mechanisms of LNSC ageing and how ageing of the LN stroma might impact autoimmune disorders are also addressed. This review aims to stimulate further research into the characterisation of aged LNSCs and the development of therapeutic interventions to improve immune function in the older adults.

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.

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.

Senescent lung fibroblasts in idiopathic pulmonary fibrosis facilitate non-small cell lung cancer progression by secreting exosomal MMP1

Lung cancer is a fatal complication of idiopathic pulmonary fibrosis (IPF) with a poor prognosis. Current treatments are insufficient in improving the prognosis of lung cancer patients with comorbid idiopathic pulmonary fibrosis (IPF-LC). Senescent fibroblasts, as stromal cells in the tumor microenvironment, influence tumor progression via exosomes. With evidence that fibroblast senescence is an important mechanism of IPF, we investigated the impact of senescent IPF lung fibroblast (diseased human lung fibroblasts, DHLF)-derived exosomes on non-small cell lung cancer (NSCLC). We found DHLF expressed significant senescence markers, and promoted NSCLC proliferation, invasion, and epithelial-mesenchymal transition. Specifically, senescent DHLF showed strong secretion of exosomes, and these exosomes enhanced the proliferation and colony-forming ability of cancer cells. Proteomic analysis showed DHLF-derived exosomes exhibited upregulated senescence-associated secretory phenotype (SASP) factors, notably MMP1, which activates the surface receptor PAR1. Knocking down MMP1 or using PAR1 inhibitors reduced the tumor-promoting effects of DHLF-derived exosomes in vivo and in vitro. Mechanistically, MMP1 acted by activating the PI3K-AKT-mTOR pathway. In conclusion, our results suggest that exosomal MMP1 derived from senescent IPF fibroblasts promotes NSCLC proliferation and colony formation by targeting PAR1 and activating the PI3K-AKT-mTOR pathway. These findings provide a novel therapeutic approach for patients with IPF-LC.

Is It Possible to Regenerate the Underactive Detrusor? Part 1. Molecular and Stem Cell Therapies Targeting the Urinary Bladder and Neural Axis - ICI-RS 2024

INTRODUCTION

Detrusor muscle weakness is commonly noted on urodynamics in patients with refractory voiding difficulty. No approved therapies have been proven to augment the strength of a detrusor voiding contraction.

METHODS

This subject was discussed by a think-tank at the International Consultation on Incontinence- Research Society (ICI-RS) meeting held in Bristol, June 2024. The discussions of the think-tank are being published in two parts. This first part discusses molecular and stem cell therapies targeting the urinary bladder and the neural axis.

RESULTS

Senescence of the urothelium and extracellular ATP acting through P2X3 receptors might be important in detrusor underactivity. Several molecules such as parasympathomimetics, acotiamide, ASP8302, neurokinin-2 agonists have been explored but none has shown unequivocal clinical benefit. Different stem cell therapy approaches have been used, chiefly in neurogenic dysfunction, with some studies showing benefit. Molecular targets for the neural axis have included TRPV-4, Bombesin, and serotoninergic receptors and TAC-302 which induces neurite growth.

CONCLUSIONS

Several options are currently being pursued in the search for an elusive molecular or stem cell option for enhancing the power of the detrusor muscle. These encompass a wide range of approaches that target each aspect of the contraction mechanism including the urothelium of bladder and urethra, myocyte, and neural pathways. While none of these have shown unequivocal clinical utility, some appear promising. Lessons from other fields of medicine might prove instructive.

CLINICAL TRIAL REGISTRATION

Not necessary. Not a clinical trial.

Gerotherapeutics: aging mechanism-based pharmaceutical and behavioral interventions to reduce cancer racial and ethnic disparities

The central premise of this article is that a portion of the established relationships between social determinants of health and racial and ethnic disparities in cancer morbidity and mortality is mediated through differences in rates of biological aging processes. We further posit that using knowledge about aging could enable discovery and testing of new mechanism-based pharmaceutical and behavioral interventions ("gerotherapeutics") to differentially improve the health of cancer survivors from minority populations and reduce cancer disparities. These hypotheses are based on evidence that lifelong differences in adverse social determinants of health contribute to disparities in rates of biological aging ("social determinants of aging"), with individuals from minoritized groups experiencing accelerated aging (ie, a steeper slope or trajectory of biological aging over time relative to chronological age) more often than individuals from nonminoritized groups. Acceleration of biological aging can increase the risk, age of onset, aggressiveness, and stage of many adult cancers. There are also documented negative feedback loops whereby the cellular damage caused by cancer and its therapies act as drivers of additional biological aging. Together, these dynamic intersectional forces can contribute to differences in cancer outcomes between survivors from minoritized vs nonminoritized populations. We highlight key targetable biological aging mechanisms with potential applications to reducing cancer disparities and discuss methodological considerations for preclinical and clinical testing of the impact of gerotherapeutics on cancer outcomes in minoritized populations. Ultimately, the promise of reducing cancer disparities will require broad societal policy changes that address the structural causes of accelerated biological aging and ensure equitable access to all new cancer control paradigms.

From Molecular Therapies to Lysosomal Transplantation and Targeted Drug Strategies: Present Applications, Limitations, and Future Prospects of Lysosomal Medications

Lysosomes are essential intracellular organelles involved in plentiful cellular processes such as cell signaling, metabolism, growth, apoptosis, autophagy, protein processing, and maintaining cellular homeostasis. Their dysfunction is linked to various diseases, including lysosomal storage disorders, inflammation, cancer, cardiovascular diseases, neurodegenerative conditions, and aging. This review focuses on current and emerging therapies for lysosomal diseases (LDs), including small medicines, enzyme replacement therapy (ERT), gene therapy, transplantation, and lysosomal drug targeting (LDT). This study was conducted through databases like PubMed, Google Scholar, Science Direct, and other research engines. To treat LDs, medicines target the lysosomal membrane, acidification processes, cathepsins, calcium signaling, mTOR, and autophagy. Moreover, small-molecule therapies using chaperones, macro-therapies like ERT, gene therapy, and gene editing technologies are used as therapy for LDs. Additionally, endosymbiotic therapy, artificial lysosomes, and lysosomal transplantation are promising options for LD management. LDT enhances the therapeutic outcomes in LDs. Extracellular vesicles and mannose-6-phosphate-tagged nanocarriers display promising approaches for improving LDT. This study concluded that lysosomes play a crucial role in the pathophysiology of numerous diseases. Thus, restoring lysosomal function is essential for treating a wide range of conditions. Despite endosymbiotic therapy, artificial lysosomes, lysosomal transplantation, and LDT offering significant potential for LD control, there are ample challenges regarding safety and ethical implications.

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.

How perceived risk of recurrence strengthens health management awareness in stroke patients: the chain mediating role of risk fear and health literacy

Background

Prior research has found that perceived risk in stroke patients motivates health behaviors in visitors. However, the role that perceived risk of recurrence in stroke patients plays in reinforcing health management awareness during the motivation phase is unclear.

Objective

This study explores this issue by examining the effects of risk fear and health literacy on health management awareness due to perceived risk of recurrence in stroke patients.

Methods

We validated the effect of perceived risk of recurrence on health management awareness and its internal mechanism by constructing a structural equation model and including 763 stroke patients, extending the relevant literature and application of the Healthy Behavior Procedural Approach (HAPA) model.

Result

The results suggest that perceived risk of recurrence in stroke patients can effectively reinforce and improve health management awareness, with risk fear and health literacy having a chain-mediated role in this group relationship.

Conclusion

This study reveals the differential effects of perceived risk of recurrence, risk fear, and health literacy in stroke patients on health management awareness at the individual level, providing valuable guidance for healthcare practitioners and families to improve patients' health outcomes and health well-being.

The role of cellular senescence in endothelial dysfunction and vascular remodelling in arteriovenous fistula maturation

Haemodialysis (HD) is often required for patients with end-stage renal disease. Arteriovenous fistulas (AVFs), a surgical procedure connecting an artery to a vein, are the preferred vascular access for HD due to their durability and lower complication rates. The aim of AVFs is to promote vein remodelling to accommodate increased blood flow needed for dialysis. However, many AVFs fail to mature properly, making them unsuitable for dialysis. Successful maturation requires remodelling, resulting in an increased luminal diameter and thickened walls to support the increased blood flow. After AVF creation, haemodynamic changes due to increased blood flow on the venous side of the AVF initiate a cascade of events that, when successful, lead to the proper maturation of the AVF, making it suitable for cannulation. In this process, endothelial cells play a crucial role since they are in direct contact with the frictional forces exerted by the blood, known as shear stress. Patients requiring HD often have other conditions that increase the burden of senescent cells, such as ageing, diabetes and hypertension. These senescent cells are characterized by irreversible growth arrest and the secretion of pro-inflammatory and pro-thrombotic factors, collectively known as the senescence-associated secretory phenotype (SASP). This accumulation can impair vascular function by promoting inflammation, reducing vasodilatation, and increasing thrombosis risk, thus hindering proper AVF maturation and function. This review explores the contribution of senescent endothelial cells to AVF maturation and explores potential therapeutic strategies to alleviate the effects of senescent cell accumulation, aiming to improve AVF maturation rates.

Cooperation between inhibitory immune checkpoints of senescent cells with immunosuppressive network to promote immunosenescence and the aging process

The accumulation of senescent cells within tissues promotes the aging process by remodelling the functions of the immune system. For many years, it has been known that senescent cells secrete pro-inflammatory cytokines and chemokines, a phenotype called the senescence-associated secretory phenotype (SASP). Chemokines and colony-stimulating factors stimulate myelopoiesis and recruit myeloid cells into aging tissues. Interestingly, recent studies have demonstrated that senescent cells are not only secretory but they also express an increased level of ligand proteins for many inhibitory immune checkpoint receptors. These ligands represent "don't eat me" markers in senescent cells and moreover, they are able to induce an exhaustion of many immune cells, such as surveying natural killer (NK) cells, cytotoxic CD8+ T cells, and macrophages. The programmed cell death protein-1 (PD-1) and its ligand PD-L1 represent the best known inhibitory immune checkpoint pathway. Importantly, the activation of inhibitory checkpoint receptors, e.g., in chronic inflammatory states, can also induce certain immune cells to differentiate toward their immunosuppressive phenotype. This can be observed in myeloid derived suppressor cells (MDSC), tissue regulatory T cells (Treg), and M2 macrophages. Conversely, these immunosuppressive cells stimulate in senescent cells the expression of many ligand proteins for inhibitory checkpoint receptors. Paradoxically, senescent cells not only promote the pro-inflammatory state but they maintain it at a low-grade level by expressing ligands for inhibitory immune checkpoint receptors. Thus, the cooperation between senescent cells and immunosuppressive cells enhances the senescence state of immune cells, i.e., immune senescence/exhaustion, and cellular senescence within tissues via bystander effects.

Preliminary Data on the Senolytic Effects of Agrimonia pilosa Ledeb. Extract Containing Agrimols for Immunosenescence in Middle-Aged Humans: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Comparison Study

OBJECTIVES

To assess the effects of agrimol-containing Agrimonia pilosa Ledeb. extract (APE) for senescent immune cell removal in middle-aged Japanese adults with immunosenescence.

DESIGN AND SETTING

A randomized, double-blind, placebo-controlled, parallel-group study was conducted in Japan between June 2023 and April 2024.

PARTICIPANTS

110 individuals aged 40-59, selected based on CD8+ T cells with highly-expressing-senescence-associated-β-galactosidase (SA-βGal).

INTERVENTION

Participants were randomly assigned to receive 50 mg APE containing 0.2 mg of agrimols or a placebo for eight consecutive weeks.

MEASUREMENTS

The primary endpoint was the change in the proportion of CD8+ T cells with high SA-βGal expression at 8 weeks of intake from the baseline. The secondary endpoints included the proportion of CD4+ T cells with high SA-βGal expression, CD4+ and CD8+ T cell subsets, and the ratio of various immune cells.

RESULTS

Of the 635 subjects screened, 110 with immunosenescence were included in this study. In total, 55 participants in the placebo group and 53 in the APE group completed the intervention. There were no statistically significant changes in either the primary or secondary endpoints due to APE intake. In the male population, the proportion of CD8+ T cells with high SA-βGal expression was reduced by APE intake (p = 0.044). Furthermore, the proportion of naïve CD8+ T cells increased and the number of effector memory CD8+ T cells decreased with the consumption of APE.

CONCLUSIONS

APE was suggested to reduce senescent immune cells, indicating its potential as a candidate senolytic agent for humans; however, the results of this study are preliminary data, and further research on APE is needed (clinical trial registration: UMIN000051574).

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.

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.

Targeting senescence to prevent diabetic kidney disease: Exploring molecular mechanisms and potential therapeutic targets for disease management

BACKGROUND/AIMS

As a microvascular complication, diabetic kidney disease is the leading cause of chronic kidney disease and end-stage renal disease worldwide. While the underlying pathophysiology driving transition of diabetic kidney disease to renal failure is yet to be fully understood, recent studies suggest that cellular senescence is central in disease development and progression. Consequently, understanding the molecular mechanisms which initiate and drive senescence in response to the diabetic milieu is crucial in developing targeted therapies that halt progression of renal disease.

METHODS

To understand the mechanistic pathways underpinning cellular senescence in the context of diabetic kidney disease, we reviewed the literature using PubMed for English language articles that contained key words related to senescence, inflammation, fibrosis, senescence-associated secretory phenotype (SASP), autophagy, and diabetes.

RESULTS

Aberrant accumulation of metabolically active senescent cells is a notable event in the progression of diabetic kidney disease. Through autocrine- and paracrine-mediated mechanisms, resident senescent cells potentiate inflammation and fibrosis through increased expression and secretion of pro-inflammatory cytokines, chemoattractants, recruitment of immune cells, myofibroblast activation, and extracellular matrix remodelling. Compounds that eliminate senescent cells and/or target the SASP - including senolytic and senomorphics drugs - demonstrate promising results in reducing the senescent cell burden and associated pro-inflammatory effect.

CONCLUSIONS

Here we evidence the link between senescence and diabetic kidney disease and highlight underlying molecular mechanisms and potential therapeutic targets that could be exploited to delay disease progression and improve outcomes for individuals with the disease. Trials are now required to translate their therapeutic potential to a clinical setting.

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.

Exploration of the mechanism and therapy of ovarian aging by targeting cellular senescence

The ovary is a crucial gonadal organ that supports female reproductive and endocrine functions. Ovarian aging can result in decreased fertility and dysfunction across multiple organs. Research has demonstrated that cellular senescence in various cell types within the ovary can trigger a decline in ovarian function through distinct stress responses, resulting in ovarian aging. This review explores how cellular senescence may contribute to ovarian aging and reproductive failure. Additionally, we discuss the factors that cause ovarian cellular senescence, including the accumulation of advanced glycation end products, oxidative stress, mitochondrial dysfunction, DNA damage, telomere shortening, and exposure to chemotherapy. Furthermore, we discuss senescence in six distinct cell types, including oocytes, granulosa cells, ovarian theca cells, immune cells, ovarian surface epithelium, and ovarian endothelial cells, inside the ovary and explore their contribution to the accelerated ovarian aging. Lastly, we describe potential senotherapeutics for the treatment of ovarian aging and offer novel strategies for ovarian longevity.

Role of chemokines in aging and age-related diseases

Chemokines (chemotactic cytokines) play essential roles in developmental process, immune cell trafficking, inflammation, immunity, angiogenesis, cellular homeostasis, aging, neurodegeneration, and tumorigenesis. Chemokines also modulate response to immunotherapy, and consequently influence the therapeutic outcome. The mechanisms underlying these processes are accomplished by interaction of chemokines with their cognate cell surface G protein-coupled receptors (GPCRs) and subsequent cellular signaling pathways. Chemokines play crucial role in influencing aging process and age-related diseases across various tissues and organs, primarily through inflammatory responses (inflammaging), recruitment of macrophages, and orchestrated trafficking of other immune cells. Chemokines are categorized in four distinct groups based on the position and number of the N-terminal cysteine residues; namely, the CC, CXC, CX3C, and (X)C. They mediate inflammatory responses, and thereby considerably impact aging process across multiple organ-systems. Therefore, understanding the underlying mechanisms mediated by chemokines may be of crucial importance in delaying and/or modulating the aging process and preventing age-related diseases. In this review, we highlight recent progress accomplished towards understanding the role of chemokines and their cellular signaling pathways involved in aging and age-relaed diseases of various organs. Moreover, we explore potential therapeutic strategies involving anti-chemokines and chemokine receptor antagonists aimed at reducing aging and mitigating age-related diseases. One of the modern methods in this direction involves use of chemokine receptor antagonists and anti-chemokines, which suppress the pro-inflammatory response, thereby helping in resolution of inflammation. Considering the wide-spectrum of functional involvements of chemokines in aging and associated diseases, several clinical trials are being conducted to develop therapeutic approaches using anti-chemokine and chemokine receptor antagonists to improve life span and promote healthy aging.

Nanodevice-Mediated Immune Cell Recruitment: Targeting Senescent Cells via MMP-3-Responsive CXCL12-Coated Nanoparticles

Senescent cells are involved in age-related disorders in different organs and are therapeutic targets for fibrotic and chronic pathologies. Immune-modulating agents, able to enhance senescent cell detection and elimination by endogenous immune cells, have emerged as pharmacological strategies. We report herein a nanoparticle for immune cell-mediated senolytic therapy designed to recruit immune cells in response to specific enzymatic matrix metalloproteinase-3 (MMP-3) activity in the senescence-associated secretory phenotype. For this, mesoporous silica nanoparticles (MSNs) are coated with a peptide substrate of the metalloproteinase MMP-3, and the peptide is decorated with chemokine CXCL12 that enhances immune cell recruitment (NPs@CXCL12). Controlled release studies confirmed the progressive and specific release of CXCL12 in the presence of MMP-3. The ability of immune cell recruitment in response to a senescent microenvironment (senescent WI-38 fibroblasts) is confirmed by Transwell migration assays with green fluorescent Jurkat T-cells, showing NPs@CXCL12 has an enhanced chemotaxis effect toward senescent cells compared to free CXCL12 (2-fold). Moreover, the cytotoxic capacity of human primary natural killer (NK) cells over senescent WI-38 is also confirmed, and their migration trajectories in response to NPs@CXCL12 or free CXCL12 are monitored by using a microfluidic device. Results confirm the ability of NPs@CXCL12 to generate a chemotactic gradient able to attract NK cells. When compared with free CXCL12, the NPs@CXCL12 system showed a reduction of up to 15.56% in the population of NK cells migrating toward free CXCL12 under competitive conditions. This study demonstrates the potential of designing nanoparticles to recruit immune cells under specific responses to eliminate senescent cells. Results confirm that NPs@CXCL12 can effectively establish a chemotactic gradient to attract NK cells.

The Potential of Polyphenols in Modulating the Cellular Senescence Process: Implications and Mechanism of Action

Background: Cellular senescence is a biological process with a dual role in organismal health. While transient senescence supports tissue repair and acts as a tumor-suppressive mechanism, the chronic accumulation of senescent cells contributes to aging and the progression of age-related diseases. Senotherapeutics, including senolytics, which selectively eliminate senescent cells, and senomorphics, which modulate the senescence-associated secretory phenotype (SASP), have emerged as promising strategies for managing age-related pathologies. Among these, polyphenols, a diverse group of plant-derived bioactive compounds, have gained attention for their potential to modulate cellular senescence. Methods: This review synthesizes evidence from in vitro, in vivo, and clinical studies on the senolytic and senomorphic activities of bioactive polyphenols, including resveratrol, kaempferol, apigenin, and fisetin. The analysis focuses on their molecular mechanisms of action and their impact on fundamental aging-related pathways. Results: Polyphenols exhibit therapeutic versatility by activating SIRT1, inhibiting NF-κB, and modulating autophagy. These compounds demonstrate a dual role, promoting the survival of healthy cells while inducing apoptosis in senescent cells. Preclinical evidence indicates their capacity to reduce SASP-associated inflammation, restore tissue homeostasis, and attenuate cellular senescence in various models of aging. Conclusions: Polyphenols represent a promising class of senotherapeutics for mitigating age-related diseases and promoting healthy lifespan extension. Further research should focus on clinical validation and the long-term effects of these compounds, paving the way for their development as therapeutic agents in geriatric medicine.

Substrate stiffness dictates unique doxorubicin-induced senescence-associated secretory phenotypes and transcriptomic signatures in human pulmonary fibroblasts

Cells are subjected to dynamic mechanical environments which impart forces and induce cellular responses. In age-related conditions like pulmonary fibrosis, there is both an increase in tissue stiffness and an accumulation of senescent cells. While senescent cells produce a senescence-associated secretory phenotype (SASP), the impact of physical stimuli on both cellular senescence and the SASP is not well understood. Here, we show that mechanical tension, modeled using cell culture substrate rigidity, influences senescent cell markers like SA-β-gal and secretory phenotypes. Comparing human primary pulmonary fibroblasts (IMR-90) cultured on physiological (2 kPa), fibrotic (50 kPa), and plastic (approximately 3 GPa) substrates, followed by senescence induction using doxorubicin, we identified unique high-stiffness-driven secretory protein profiles using mass spectrometry and transcriptomic signatures, both showing an enrichment in collagen proteins. Consistently, clusters of p21 + cells are seen in fibrotic regions of bleomycin induced pulmonary fibrosis in mice. Computational meta-analysis of single-cell RNA sequencing datasets from human interstitial lung disease confirmed these stiffness SASP genes are highly expressed in disease fibroblasts and strongly correlate with mechanotransduction and senescence-related pathways. Thus, mechanical forces shape cell senescence and their secretory phenotypes.

The Fifth Annual Symposium of the Midwest Aging Consortium

As the healthcare burden caused by an increasingly aging population rapidly rises, a pressing need exists for innovative geroscience research that can elucidate aging mechanisms and precipitate the development of therapeutic interventions to support healthy aging. The Fifth Annual Midwest Aging Consortium Aging Research symposium, held from April 28 to 30, 2024, was hosted by The Ohio State University in Columbus, Ohio, and featured presentations from investigators across the Midwestern United States. This report summarizes the research presented at the symposium, whose topics included cellular senescence and the aging brain, metabolism and metabolic interventions, nutrition, redox mechanisms and biomarkers, and stress mechanisms. Abstract presentations and short talks highlighted early-stage and young investigators, whereas 2 keynote presentations anchored the symposium. Overall, this symposium showed the robustness of aging research in the Midwest and underscored the advantages of a collaborative approach to geroscience research.

Comparative evaluation of cellular senescence in naturally aged and stress-induced murine macrophages for identifying optimum senescent macrophage study systems

BACKGROUND

The role and relevance of macrophages both as causes and therapeutics of cellular senescence is rapidly emerging. However, current knowledge regarding the extent and depth of senescence in macrophages in vivo is limited and controversial. Further, acute models of stress-induced senescence in transformed/cancerous macrophage cell lines are being used although their efficacy and relevance are not characterized.

METHODS AND RESULTS

The present study sought to address these aspects by first comparing prevalent senescence in naturally aged murine peritoneal macrophages, and then assessing the effects of two different stressors (LPS and H2O2) in inducing premature senescence in young peritoneal macrophages. Next, RAW264.7 cell line was exposed to respective stressors and their efficiency in recapitulating the effects of natural senescence markers was characterized. We observed strong upregulation of primary markers of senescence such as SA-β-gal activity, p53, p21, p16Inka4a, Rb, ATM, and Lamin B1in naturally aged mice along with increased SASP proteins (IL-6/TNF-α/MCP-1) and redox stress (ROS and NO). Aged macrophages also demonstrated severely reduced phagocytosis. Exposure to both LPS and H2O2 in young macrophages invoked the expression of all primary markers of senescence although SASP protein expression was exaggerated in LPS stimulation. Similarly, ROS and NO expression increased while phagocytosis decreased. Stimulation of RAW264.7 cells generally revealed a similar trend although the depth of all measured parameters was ostensibly stronger in young peritoneal macrophages. Among the two stressors, LPS stimulation appeared to be relatively more potent.

CONCLUSION

Overall, this study emphasizes that LPS exposure to young peritoneal macrophages more strongly recapitulates in vivo cellular senescence in macrophages.

Combination of rapamycin and adipose-derived mesenchymal stromal cells enhances therapeutic potential for osteoarthritis

BACKGROUND

The regenerative potential of mesenchymal stromal/stem cells (MSCs) has been extensively studied in clinical trials in the past decade. However, despite the promising regenerative properties documented in preclinical studies, for instance in osteoarthritis (OA), the therapeutic translation of these results in patients has not been fully conclusive. One factor contributing to this therapeutic barrier could be the presence of senescent cells in OA joints.

METHODS

This study evaluated a novel approach to OA treatment by combining adipose tissue-derived MSCs (AD-MSCs) with rapamycin, a clinically approved immunosuppressive drug with anti-senescence properties. First, rapamycin effects on senescence and fibrosis markers were investigated in freshly isolated OA chondrocytes by immunostaining. Next, the in vitro differentiation capacities of AD-MSCs, their regulatory immune functions on activated immune cells and their regenerative effects on OA chondrocyte signature were assessed in the presence of rapamycin.

RESULTS

In OA chondrocytes, rapamycin reduced the senescence marker p15INK4B and the fibrosis marker COL1A1 without affecting the expression of the master chondrogenic markers SOX9 and COL2. Rapamycin also enhanced AD-MSC differentiation into chondrocytes and reduced their differentiation into adipocytes. In addition, rapamycin improved AD-MSC immunoregulatory functions by promoting the expression of immunosuppressive factors, such as IDO1, PTGS2 and also CD274 (encoding PD-L1). Finally, RNA sequencing analysis showed that in the presence of rapamycin, AD-MSCs displayed improved chondroprotective regenerative effects on co-cultured OA chondrocytes.

CONCLUSIONS

Our findings suggest that the rapamycin and AD-MSC combination enhances the therapeutic efficacy of these cells in senescence-driven degenerative diseases such as OA, notably by improving their anti-fibrotic and anti-inflammatory properties.

Design of a Magnetic Nanoplatform Based on CD26 Targeting and HSP90 Inhibition for Apoptosis and Ferroptosis-Mediated Elimination of Senescent Cells

The accumulation of senescent cells, a hallmark of aging and age-related diseases, is also considered as a side effect of anticancer therapies, promoting drug resistance and leading to treatment failure. The use of senolytics, selective inducers of cell death in senescent cells, is a promising pharmacological antiaging and anticancer approach. However, more studies are needed to overcome the limitations of first-generation senolytics by the design of targeted senolytics and nanosenolytics and the validation of their usefulness in biological systems. In the present study, we have designed a nanoplatform composed of iron oxide nanoparticles functionalized with an antibody against a cell surface marker of senescent cells (CD26), and loaded with the senolytic drug HSP90 inhibitor 17-DMAG (MNP@CD26@17D). We have documented its action against oxidative stress-induced senescent human fibroblasts, WI-38 and BJ cells, and anticancer drug-induced senescent cutaneous squamous cell carcinoma A431 cells, demonstrating for the first time that CD26 is a valid marker of senescence in cancer cells. A dual response to MNP@CD26@17D stimulation in senescent cells was revealed, namely, apoptosis-based early response (2 h treatment) and ferroptosis-based late response (24 h treatment). MNP@CD26@17D-mediated ferroptosis might be executed by ferritinophagy as judged by elevated levels of the ferritinophagy marker NCOA4 and a decreased pool of ferritin. As 24 h treatment with MNP@CD26@17D did not induce hemolysis in human erythrocytes in vitro, this newly designed nanoplatform could be considered as an optimal multifunctional tool to target and eliminate senescent cells of skin origin, overcoming their apoptosis resistance.

Phosphoproteomic analysis reveals the mechanisms of human umbilical cord mesenchymal stem cell-derived exosomes attenuate renal aging

Aging is a critical biological process, with particularly notable impacts on the kidneys. Exosomes derived from human umbilical cord mesenchymal stem cells (hUC-MSCs) are capable of transferring various bioactive molecules, which exhibit beneficial therapeutic effects on kidney diseases. This study demonstrates that exosomes derived from hUC-MSCs ameliorate cellular senescence in the kidneys of naturally aging mice. These exosomes reduce the protein expression of senescence markers and senescence-associated secretory phenotypes (SASP) leading to fewer DNA damage foci and increased expression of the proliferation indicator Ki67. During the aging process, many proteins undergo phosphorylation modifications. We utilized data-independent acquisition (DIA) phosphoproteomics to study kidneys of naturally aging mice and those treated with hUC-MSC-derived exosomes. We observed elevated phosphorylation levels of the differentially phosphorylated proteins, Lamin A/C, at Ser390 and Ser392 sites, which were subsequently verified by western blotting. Overall, this study provides a new molecular characterization of hUC-MSC-derived exosomes in mitigating cellular senescence in the kidneys. SIGNIFICANCE: DIA phosphoproteomics was employed to investigate phosphorylated proteins in the kidney tissues of naturally aging mice with hUCMSC-exos treated. The results demonstrated that the DIA technique detected a higher abundance of phosphorylated proteins. We identified 24 significantly differentially phosphorylated proteins, and found that the phosphorylation of specific Lamin A/C sites is crucial for preventing cellular senescence. This study will help to better reveal the related phosphorylated proteins involved in hUCMSC-exos intervention in the kidneys of naturally aging mice, providing a foundation for future research on specific phosphorylation sites of proteins as potential therapeutic targets for renal aging-related diseases.