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IGFBP7 is a key component of the senescence-associated secretory phenotype (SASP) that induces senescence in healthy cells by modulating the insulin, IGF, and activin A pathways.

Senescent cells exert their effects through the release of various factors, collectively referred to as the senescence-associated secretory phenotype (SASP). The SASP can induce senescence in healthy cells (secondary senescence), modulate immune system function, reshape the extracellular matrix, and facilitate cancer progression.Among SASP components, certain factors act as key regulators in the induction of secondary senescence. In this study, we evaluated the role of IGFBP7, a crucial SASP component. Our results demonstrated that ROS-prostaglandin signaling is involved in the release of IGFBP7. Furthermore, neutralizing antibodies targeting IGFBP7 attenuated the SASP's pro-senescence activity. Cells incubated with IGFBP7 also entered a state of senescence.The senescence induced by IGFBP7 appears to be mediated through three primary pathways. First, IGFBP7 can bind to insulin, thereby inhibiting its anti-senescence and pro-growth effects. In addition to this inhibitory effect on the insulin pathway, IGFBP7 may enhance IGFII pro-senescence signaling by promoting its interaction with IGF2R while blocking IGF1R. These activities are dependent on ERK and AKT signaling pathways. Finally, IGFBP7 and Activin A, both of which can induce cellular senescence, appear to regulate and inhibit each other, suggesting a compensatory mechanism to prevent excessive senescence. Notably, our preliminary data indicate that IGFBP7, in addition to blocking Activin A, may interact with its receptors and induce senescence via SMAD pathways.Our findings highlight that IGFBP7, along with other members of the IGFBP family, plays a pivotal role in senescence-related signaling pathways. Therefore, IGFBP7 may serve as a potential target for anti-aging strategies aimed at reducing the burden of senescence on tissues and organs.

Insulin-Like Growth Factor Binding Proteins

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

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

Animals

DNA methylation as a driver of lung fibroblast senescence in COPD.

Cellular senescence is increasingly recognized as a hallmark of chronic obstructive pulmonary disease (COPD), with higher levels in lung fibroblasts from COPD patients. Upon senescence, both hypomethylation and hypermethylation have been described but not in COPD-derived fibroblasts yet. This study investigated whether altered DNA methylation can be a driver of fibroblast senescence in COPD. Genome-wide gene expression and DNA methylation data were generated from primary lung fibroblasts of 11 COPD stage IV patients and 10 matched controls. Gene expression of six well-known senescence genes was compared between COPD and control. COPD-associated senescence genes were correlated with their related CpG sites in an expression quantitative trait methylation (eQTM) analysis. Methylation levels of significant eQTMs were compared between COPD and control fibroblasts. A causal relationship between altered DNA methylation and senescence was validated in 5-Aza-2'-deoxycytidine (5-Aza-2'-dC)-treated primary lung fibroblasts. Gene expression of CDKN1A, CDKN2A, and CDKN2B was higher, while LMNB1 expression was lower in COPD-derived fibroblasts compared to controls. A total of 19 eQTMs were found for the COPD-associated senescence genes CDKN1A (9), CDKN2A (1), and LMNB1 (9). Among these, seven CpG sites (4 for CDKN1A and 3 for LMNB1) exhibited differential methylation between COPD and control. Treatment with 5-Aza-2'-dC led to global demethylation and increased senescence and, importantly, confirmed the association between senescence and hypomethylation of the COPD-associated CpG site cg04924375. Altered DNA methylation is linked to fibroblast senescence in COPD, and seven CpG sites are identified as potential epigenetic regulators of the senescence genes CDKN1A and LMNB1.NEW & NOTEWORTHY This study identifies DNA methylation as a mechanistic contributor to lung fibroblast senescence in chronic obstructive pulmonary disease (COPD). By integrating DNA methylation data with the transcriptomic data of senescence-related genes, we uncovered seven COPD-associated CpG sites linked to the senescence regulators CDKN1A and LMNB1. Pharmacological demethylation induces fibroblast senescence and is consistent with a functional role for hypomethylation at cg04924375, providing new insight into epigenetic regulation of cellular senescence in COPD lung fibroblasts.

Humans

Senescent fibroblasts drive CD8+ T cell dysfunction in colorectal cancer via CD36-mediated lipid transfer and peroxidation.

BACKGROUND: Functional exhaustion of tumor-infiltrating CD8+ T cells represents a hallmark of colorectal cancer (CRC) immunosuppression, though its mechanistic drivers remain elusive. Given the established correlation between CRC progression and stromal senescence characterized by pathological lipid accumulation and impaired immunity, we investigated whether and how senescent fibroblasts actively regulate CD8+ T cell dysfunction. METHODS: Single-cell RNA sequencing (scRNA-seq) analysis was conducted to unveil the diverse fibroblast populations and the significant lipid metabolism changes between senescent fibroblasts and non-senescent fibroblasts in human CRC specimens and adjacent normal mucosa. Machine-learning identified senescent fibroblasts with a distinct gene signature. Cell-cell communication analysis was used to evaluate the interactions between senescent fibroblasts and CD8+ T cells in colorectal cancer. Co-culture experiments were conducted among senescent fibroblasts, CD8+ T cells and patient-derived organoids of CRC (CRC-PDOs), with the results evaluated with high-content imaging and propidium iodide/Hoechst 33,342 staining. Flow cytometry, ELISA and lipid pulse-chase with BODIPY FL C16 were performed to detect the alterations of CD8+ T cell cytotoxic function and metabolic status. AOM/DSS-induced CRC mouse model was used to conduct in vivo validation to evaluate whether senolytics could suppress CRC progression. Patients from the Cancer Genome Atlas colorectal cancer cohort were stratified into CD36-high and CD36-low groups by median expression, and drug sensitivity for GDSC2 compounds was predicted computationally using the oncoPredict R package. RESULTS: ScRNA-seq demonstrated the specific cell population presence and divergence of senescent fibroblasts between neoplastic and histologically normal adjacent cell clusters in CRC. Random Forest was employed for cell senescence classification. Feature importance analysis identified five genes as key contributors to the model’s decision process. Cell-cell communication analysis revealed enhanced interactions between senescent fibroblasts and CD8+ T cells in CRC. Co-culture of senescent fibroblasts significantly impaired the cytotoxic functions of CD8+ T cells on CRC-PDOs, which was reflected by the declined proportions of granzyme B (GZMB) + and interferon gamma (IFNγ) + CD8+ T cells and enhanced viability of CRC-PDOs. Mechanistically, the co-culture with senescent fibroblasts promoted the lipid shuttling into CD8+ T cells to induce lipid peroxidation and downstream impairment of cytotoxicity. Furthermore, the inhibition of CD36, the specific scavenger receptor for lipid uptake of CD8+ T cells, effectively suppressed lipid transfer and peroxidation thereby preserving the effector functions of CD8+ T cells and ultimately promoting tumor apoptosis. Complementarily, in vivo senolytic treatment significantly suppressed CRC progression in AOM-DSS CRC mouse models. Top 12 therapeutic agents were identified significantly enhanced predicted efficacy in CD36-high tumors. CONCLUSIONS: Our study identified a substantial population of senescent fibroblasts in human CRC through single cell transcriptomics, machine-learning and clinical biopsies. These senescent fibroblasts impair CD8+ T cell-mediated killing of CRC-PDOs via CD36-dependent lipid transfer, suggesting senolytic targeting of stromal cells as a promising immunotherapeutic strategy for CRC.

Colorectal Neoplasms

Tissue specificity of senescent cell accumulation during physiologic and accelerated aging of mice.

Senescent cells accumulate with age in vertebrates and promote aging largely through their senescence-associated secretory phenotype (SASP). Many types of stress induce senescence, including genotoxic stress. ERCC1-XPF is a DNA repair endonuclease required for multiple DNA repair mechanisms that protect the nuclear genome. Humans or mice with reduced expression of this enzyme age rapidly due to increased levels of spontaneous, genotoxic stress. Here, we asked whether this corresponds to an increased level of senescent cells. p16Ink4a and p21Cip1 mRNA were increased ~15-fold in peripheral lymphocytes from 4- to 5-month-old Ercc1-/∆ and 2.5-year-old wild-type (WT) mice, suggesting that these animals exhibit a similar biological age. p16Ink4a and p21Cip1 mRNA were elevated in 10 of 13 tissues analyzed from 4- to 5-month-old Ercc1-/∆ mice, indicating where endogenous DNA damage drives senescence in vivo. Aged WT mice had similar increases of p16Ink4a and p21Cip1 mRNA in the same 10 tissues as the mutant mice. Senescence-associated β-galactosidase activity and p21Cip1 protein also were increased in tissues of the progeroid and aged mice, while Lamin B1 mRNA and protein levels were diminished. In Ercc1-/Δ mice with a p16Ink4a luciferase reporter, bioluminescence rose steadily with age, particularly in lung, thymus, and pancreas. These data illustrate where senescence occurs with natural and accelerated aging in mice and the relative extent of senescence among tissues. Interestingly, senescence was greater in male mice until the end of life. The similarities between Ercc1-/∆ and aged WT mice support the conclusion that the DNA repair-deficient mice accurately model the age-related accumulation of senescent cells, albeit six-times faster.

Aging

Methylation histology reveals the molecular mechanism by which red light-mediated DNA methylation delays leaf senescence in pak choi (Brassica rapa subsp. chinensis).

Leaf senescence is a key factor affecting the postharvest quality and shelf life of vegetables. The specific mechanisms by which light environment and DNA methylation mediate leaf senescence remain unclear. This study explored the molecular mechanism by which red light (RL) LED delays leaf senescence through DNA methylation in pak choi (Brassica rapa subsp. chinensis). In this study, RL treatment significantly suppressed leaf senescence in pak choi during postharvest storage and downregulated the expression of senescence-associated genes (SAGs). Experiments with methylation inhibitors confirmed its association with DNA methylation. Furthermore, whole-genome bisulfite sequencing revealed that during storage-induced senescence, pak choi exhibited significantly reduced methylation levels across its genome, particularly in promoter regions, and RL treatment reversed this effect. Furthermore, virus-induced gene silencing and overexpression experiments confirmed the central role of the demethylase BrDML3 (BraA01g004250.3.5C) in this process. Subsequently, a transcription factor under its regulation, BrNAC55 (BraA05g032630.3.5C), was identified and shown to promote leaf senescence by activating downstream SAGs (BrSGR1, BrPPH, BrSAUR36) to promote leaf senescence. In addition, this study found that BrNAC55 can also form a feedback loop with BrDML3, continuously amplifying leaf senescence. This study elucidates the mechanism by which RL-mediated DNA methylation delays leaf senescence, providing a foundation for postharvest preservation technologies.

DNA Methylation

p21-senescent cells drive pancreatic islet dysfunction through targetable paracrine signaling in type 2 diabetes.

Cellular senescence is an irreversible stress response, which leads to loss of cellular function and remodeling of the cellular secretory profile. In humans, pancreatic β cells undergo cellular senescence during the progression to type 2 diabetes (T2D). However, the mechanism linking β cell senescence to islet dysfunction remains unknown, and thus the therapeutic potential of targeting senescent cells in T2D is not established. Herein, we identified a subpopulation of senescent β cells expressing p21, which emerged early in the progression of T2D in humans and mice. Spatial transcriptomics and proteomics analyses confirmed senescence and loss of cellular identity in this subpopulation in humans. Functional analysis revealed lack of glucose responsiveness, high basal insulin secretion, and transcription of senescence-associated secretory phenotype (SASP) factors. SASP factors from p21+ β cells induced secondary senescence in neighboring cells, characterized by dysfunction and loss of identity. JAK inhibitors counteracted the induction of secondary senescence and restored β cell function in islets from humans with T2D and in mice fed a high-fat diet. These findings reveal the critical role of p21+ β cells in T2D pathogenesis and the therapeutic potential of targeting this pathophysiological process.

Animals

Cardiomyocyte-Specific Plakophilin-2 Loss Is Sufficient to Induce Aging and Senescence of Nonmyocytes: Relevance to Arrhythmogenic Cardiomyopathy.

BACKGROUND: Pathogenic variants in PKP2 are the most common cause of familial arrhythmogenic right ventricular cardiomyopathy. This study tests whether plakophilin-2 (PKP2) deficiency only in cardiomyocytes is sufficient to provoke premature aging and proinflammatory senescence in nonmyocyte, cardiac resident cells. METHODS: We studied mice with cardiomyocyte-specific, tamoxifen-activated loss of PKP2 (cardiomyocyte-specific conditional knockout of plakophilin-2) using conventional and multiplex imaging, cytokine arrays, epigenetic clocks, spatial transcriptomics, expansion and structured illumination microscopy, and correlative data analysis. We examined nonmyocytes and cardiomyocytes for premature aging and senescence. RESULTS: We observed senescence-associated heterochromatin foci in nonmyocytes, predominantly in cells positive for α-smooth muscle actin staining. Cytokines in media of nonmyocyte cells were consistent with senescence-associated secretory phenotype. Epigenetic clocks identified premature aging. Multiplex immunohistochemistry showed nonmyocyte cells in niches, intermingled with cardiomyocytes. Spatial transcriptomics showed overrepresentation of senescence-associated secretory phenotype-related transcripts, predominantly in myocyte-rich areas of the left ventricle. Senescence-associated heterochromatin foci and increased epigenetic age were not found in cardiomyocytes from cardiomyocyte-specific conditional knockout of plakophilin-2 hearts, although we observed structural features associated with premature aging. Cross-reference analysis showed correlation between the cardiomyocyte-specific conditional knockout of plakophilin-2 cardiac proteome and that of mice 5 or 6 times their chronological age, as well as transcriptional signatures of neurodegenerative diseases. CONCLUSIONS: Loss of PKP2 expression only in adult cardiac myocytes is sufficient to induce proinflammatory senescence in nonmyocytes, and overall premature cardiac aging. This is the first study to intersect cellular senescence and premature aging with desmosomal arrhythmogenic cardiomyopathies. We speculate that cell-agnostic molecular signatures, biomarkers, and pharmacology of senescence and of neurodegenerative diseases may be relevant to diagnose or treat PKP2 arrhythmogenic right ventricular cardiomyopathy.

Animals

The impacts of chronic infections on shaping cellular senescence.

Cellular senescence is a fundamental biological process characterized by stable cell cycle arrest, genomic instability, and the acquisition of a proinflammatory secretory phenotype. While senescence is traditionally associated with aging, growing evidence reveals that chronic infections such as viral, bacterial, and protozoan parasites can serve as powerful inducers of senescence, contributing to premature aging and long-term tissue damage. This review explores the diverse mechanisms by which persistent pathogens trigger or sustain senescence in host cells. We highlight how these chronic infections manipulate host DNA repair, mitochondrial dynamics, telomere maintenance, oxidative stress, and immune function to promote senescence and immunosenescence. Emerging findings also reveal how pathogens hijack the host cellular machinery to induce senescence across various tissue types. In many cases, senescence not only enables pathogen persistence but also drives pathological outcomes such as fibrosis, neurodegeneration, cardiomyopathy, and immune exhaustion. Collectively, this emerging evidence highlights a unifying strategy among diverse pathogens: the exploitation of cellular senescence to support chronic infection and promote disease. Understanding how infectious agents drive senescence offers new insights into age-related pathologies and highlights potential therapeutic targets, such as senolytic and senomorphic agents, to mitigate the long-term impacts of chronic infections.

Bacterial infection

Pharmacologic activation of Δ133p53α reduces cellular senescence in progeria patients-derived cells.

BACKGROUND: Patients with Hutchinson-Gilford progeria syndrome (HGPS) show accelerated aging phenotypes and have shortened lifespan, with implications in physiological aging processes as well. While therapeutic approaches targeting the disease-causing abnormal protein, progerin, have been developed, further efforts to explore mechanistically distinct and complementary strategies are still critical to better treatment regimens. We previously showed that lentiviral vector-driven expression of Δ133p53α, a natural inhibitory isoform of p53, rescued HGPS patients-derived fibroblasts from early entry into cellular senescence, which is a downstream event of progerin-induced DNA damage. We also performed a quantitative high-throughput screen (qHTS) of approved drug and investigational agent libraries, leading to the identification of celastrol and AZD1981 as compounds that upregulate Δ133p53α protein levels. METHODS: To investigate whether celastrol and ADZ1981 upregulate endogenous Δ133p53α in HGPS-derived fibroblasts and reduce their senescence-associated phenotypes, we performed western blot assays (Δ133p53α, progerin, and p21WAF1, which mediates p53-induced senescence and is inhibited by Δ133p53α), senescence-associated β-galactosidase (SA-β-gal) staining, enzyme-linked immunosorbent assay (IL-6, which is a proinflammatory cytokine secreted from senescent cells), and qRT-PCR assays (p21WAF1 and IL-6). RESULTS: Treatment with celastrol (0.1 μM for 24 h) or AZD1981 (10 μM for 24 h) reproducibly increased Δ133p53α expression and decreased p21WAF1 expression in two strains of fibroblasts derived from HGPS patients. These compounds reduced the percentage of SA-β-gal-positive senescent cells and the secretion of IL-6 into culture medium in both of these fibroblast strains, irrespective of their different basal levels of senescence and IL-6 secretion. These compounds had no effect on the level of progerin. CONCLUSION: Celastrol and ADZ1981 upregulate endogenous Δ133p53α and, reproducing the effects of its vector-driven expression, inhibit cellular senescence and IL-6 secretion in HGPS-derived fibroblasts. Their progerin-independent action suggests that they may synergize with currently available progerin-targeting therapies. This study also warrants further investigation of these compounds for potential applications in other diseases and conditions in which Δ133p53α-regulated senescence plays a role.

Hutchinson-Gilford progeria syndrome

Quantitative proteomics reveals coordinated changes in the proteome during replicative senescence.

Cellular senescence is a state of irreversible cell cycle arrest triggered by telomere erosion, persistent DNA damage or chronic stress. The accumulation of senescent cells disrupts tissue function and contributes to aging and disease. Here, we employ mass spectrometry-based proteomics to systematically interrogate dynamic proteome changes at multiple levels during the progression of replicative cellular senescence. We demonstrate that proteome changes during senescence occur in a coordinated manner, characterized by widespread protein depletion on chromatin. Moreover, components of the cytoplasmic translation machinery are depleted, while mitochondrial proteins display increased insolubility. Autophagic and proteasome activity is compromised in senescent cells along with remodeling of ubiquitin linkages and depletion of ubiquitin E3 ligases. Comparison of the senescent proteome with different pathophysiological cellular states reveals a distinctive senescent signature shaped by changes in the proteostasis network. Collectively, we provide a resource for the exploration of temporally resolved changes in the senescent proteome.

Cellular Senescence

Chromosomal and extrachromosomal control of senescence in the ascomycete Podospora anserina.

In Podospora anserina senescence leading to cellular death occurs regularly after prolonged vegetative propagation. However, the life span of this ascomycete may be extended by various means: 1. Mutations in a least 8 morphogenetic genes belonging to 4 linkage groups postpone drastically or even prevent in certain pairwise combinations (e.g. i viv) the onset of senescence. 2. Inhibitors of mt DNA and of mitochondrial protein synthesis show a life prolonging effect when added in low concentrations to the growth medium. 3. A similar effect was found when mycelia were fed exclusively on non repressive carbon sources. Whereas the anti-aging effect of specific mutated genes is rather permanent, the life prolonging action of the inhibitors and carbon sources is restricted and temporary. These substances have no long lasting effect, since after their removal from the medium aging proceeds. Physiological experiments have further shown the existence of three phases in the life span of Podospora anserina. During the juvenile phase aging is prevented by all of these compounds; during the presenescent phase aging is prevented by inhibitors of mt DNA only, and during the senescent phase aging is irreversible. Senescence may be induced in juvenile protoplasts by DNA extracted from senescent mycelia. This, together with the well known fact that senescence is extrachromosomically inherited, points to extrachromosomal DNA as the causative agent of senescence. This kind of DNA may be connected with or perhaps located in the mitochondria. Collectively, the data are consistent in showing that the syndrome of senescence in Podospora anserina is controlled by a chromosomal-extrachromosomal interaction. In this system, extrachromosomal DNA, perhaps a mt DNA, is identical with the infectious principle initiating the decay of the cell, and nuclear genes supervise its expression.

Aging

USP22 alleviates oxidative stress-induced BMSCs senescence by stabilizing SPI1 protein.

BACKGROUND: Therapeutic efficacy of bone marrow mesenchymal stem cell (BMSC) transplantation is often compromised by cellular senescence and diminished osteogenic potential induced by oxidative stress. Nevertheless, the underlying molecular mechanisms remain poorly understood. This study explores the role of ubiquitin-specific peptidase 22 (USP22) in regulating oxidative stress-induced BMSCs senescence. METHODS: BMSCs were exposed to H2O2 to mimics oxidative stress conditions. An ovariectomy‑induced osteoporotic rat model was established. Cell viability was assessed by CCK8 assay. ROS level and NAD+ level were measured by the DHE probe and kit, respectively. SA-β-gal staining was employed to detect cellular senescence. Mineralization was determined using ARS staining. Protein-DNA interactions (SPI1-NAMPT promoter) were examined through ChIP and luciferase reporter assays. Co-IP and ubiquitination assays were performed to validate USP22-SPI1 binding and post-translational modifications. RESULTS: SPI1 expression declined in H2O2-treated BMSCs and osteoporotic rat model, and its overexpression rescued H2O2-induced BMSCs senescence and osteogenic differentiation impairment. Mechanistically, SPI1 mediated protection on oxidative stress-induced BMSCs senescence by transcriptionally activating NAMPT expression and elevating NAD+ level. In addition, USP22 stabilized SPI1 protein through deubiquitination modification. As expected, USP22 overexpression alleviated oxidative stress-induced BMSCs senescence and osteogenic differentiation impairment, while these effects were reversed by SPI1 knockdown. CONCLUSION: USP22 mitigated oxidative stress-induced BMSCs senescence and preserved osteogenic capacity by promoting NAMPT transcription through deubiquitinating and stabilizing SPI1 protein.

Oxidative Stress

TGA6 directly activates ABF2 and ABF3 to promote leaf senescence in Arabidopsis thaliana.

Leaf senescence is a tightly regulated developmental process governed by a complex transcriptional network. Although the TGACG motif-binding (TGA) family of basic leucine zipper (bZIP) transcription factors are well-characterized regulators of plant defense responses, their roles in leaf senescence remain poorly understood. Here, we report that overexpression of TGA6 in Arabidopsis thaliana promotes early leaf senescence. Independent TGA6-overexpressing lines displayed premature leaf yellowing and significantly lower chlorophyll levels than wild-type (WT) plants under both normal growth and dark-induced senescence conditions. At the molecular level, RT-qPCR analysis revealed significant upregulation of canonical senescence marker genes, including NYC1, PAO, SAG12, SAG13, SGR1, and SGR2, in the TGA6-OE lines relative to WT plants. Furthermore, we found that the transcript levels of ABA-responsive element binding factor 2 (ABF2) and ABF3, which act upstream of these senescence markers, were significantly elevated in the TGA6-OE lines. Dual-luciferase reporter assays and electrophoretic mobility shift assay demonstrated that TGA6 directly binds to the TGACG motifs within the promoters of ABF2 and ABF3 to activate their transcription. Collectively, these findings demonstrate that TGA6 functions as a positive regulator of leaf senescence.

Arabidopsis

Multiomics analysis reveals that senescent CXCL16+ macrophages promote lung adenocarcinoma progression through TGF-β signalling.

BACKGROUND: Lung adenocarcinoma (LUAD) is the most common histological subtype of lung cancer and remains a leading cause of cancer-related mortality worldwide. Although, immunotherapy has become a cornerstone of first-line treatment, only 20-30% of patients achieve a durable clinical benefit, largely because of the complexity and heterogeneity of the tumour immune microenvironment. Emerging evidence indicates that cellular senescence, particularly within immune cells, contributes to tumour progression by impairing antitumour immunity; however, its mechanistic role in LUAD remains incompletely understood. METHODS: We performed an integrative multiomics analysis incorporating genome-wide association studies (GWASs), bulk RNA sequencing, single-cell RNA sequencing, and spatial transcriptomics to characterize immune heterogeneity in LUAD. Cellular senescence was validated by performing staining for senescence-associated β-galactosidase and the canonical markers p16 and p21. SHAP analysis was applied to evaluate the contribution of CXCL16+ macrophages. Functional roles were assessed using coculture assays, in vitro and in vivo tumour models, orthotopic tumour implantation, and multiplex immunofluorescence staining of clinical specimens. RESULTS: A summary data-based on Mendelian randomization analysis integrating GWAS and TCGA data identified CXCL16 as a senescence-associated gene that is causally linked to the LUAD risk. Single-cell RNA sequencing revealed that CXCL16 is predominantly expressed in macrophages, and the pseudotime analysis together with β-galactosidase staining confirmed its association with macrophage senescence. Spatial transcriptomics and immunofluorescence staining showed the marked enrichment of CXCL16+ macrophages in LUAD tissues. The cell-cell communication analysis further revealed a strong association between the number of CXCL16+ macrophages and the activation of the TGF-β signalling pathway within the tumour microenvironment. Functionally, CXCL16+ macrophages promoted LUAD progression via TGF-β signalling, as validated in vitro and in subcutaneous and orthotopic tumour models. Molecular dynamics simulations additionally suggested that LUAD patients with high levels of CXCL16+ macrophage infiltration may exhibit increased sensitivity to bosutinib. CONCLUSIONS: CXCL16 promotes macrophage senescence, and senescent CXCL16+ macrophages drive LUAD progression through TGF-β signalling. These findings identify CXCL16+ macrophages as a biologically and therapeutically relevant immune cell population, highlighting a potential target for precision intervention in LUAD.

Humans

Small extracellular vesicles reflect senescence progression in human bone marrow-derived mesenchymal stem cells during hollow fiber bioreactor culture.

Prolonged three-dimensional culture exposes stem cells to sustain microenvironmental and mechanical stresses that can promote aging- and senescence-associated phenotypic alterations. This study examined how long-term expansion of human bone marrow-derived mesenchymal stem cells (BMSCs) in a hollow fiber bioreactor (HFB) influences cellular senescence and the molecular composition of secreted small extracellular vesicles (sEVs). During extended HFB culture, BMSCs exhibited progressive morphological flattening and cytoskeletal disorganization, accompanied by increased senescence-associated β-galactosidase activity and immunophenotypic remodeling characterized by reduced fluorescence intensity and spatial redistribution of canonical MSC markers, consistent with a stress-adapted, early senescence-associated cellular state. In parallel, sEVs were collected longitudinally over 40 days and characterized by nanoparticle tracking analysis, immunoblotting, and quantitative proteomics. While vesicle size, marker expression, and yield remained stable throughout culture, proteomic profiling revealed pronounced, phase-dependent remodeling of sEV cargo, including coordinated alterations in oxidative stress-related processes, lysosomal and extracellular matrix-associated pathways, and relative depletion of cytoskeletal and translational components. Notably, these vesicular signatures closely mirrored senescence-associated changes observed at the cellular level. The strong correspondence between cellular phenotypes and sEV proteomic profiles establishes vesicle analysis as a convergent and noninvasive readout of BMSC aging, enabling sensitive monitoring of senescence progression while reducing reliance on parallel, labor-intensive cellular assays. Collectively, these findings indicate that prolonged HFB culture promotes a controlled, stress-associated senescence program in BMSCs and position sEV proteomic profiling as a robust approach for assessing stem cell aging dynamics during long-term three-dimensional bioreactor culture.

Mesenchymal Stem Cells

Direct targeting of ORAI1 by ginsenoside Rg3 modulates calcium signaling and senescence-associated AMPK-NRF2 activation.

BACKGROUND: 20(S)-ginsenoside Rg3 (Rg3(S)), a major saponin derived from red ginseng, exhibits diverse biological activities, including antioxidant and anti-senescence effects. However, the direct molecular targets through which Rg3(S) regulates calcium signaling and its role at membrane contact sites during cellular senescence remain largely unknown. METHODS: Plasma membrane (PM)-endoplasmic reticulum (ER) contacts and related protein interactions were analyzed using proximity ligation assays and co-immunoprecipitation. Direct binding of Rg3(S) to ORAI1 was validated using cellular thermal shift assays and microscale thermophoresis. Molecular docking simulations followed by site-directed mutagenesis were used to define critical binding residues. Cytosolic calcium levels and cellular senescence were assessed using calcium imaging and senescence-associated β-galactosidase staining. RESULTS: Rg3(S) increased cytosolic calcium levels independently of ER calcium depletion and was accompanied by a reduction in PM-ER contacts. Rg3(S) directly bound to ORAI1 in a dose-dependent manner, identifying ORAI1 as a previously unrecognized molecular target of ginsenoside Rg3. Molecular docking revealed LYS204 and ILE229 within the extracellular loop of ORAI1 as key residues maintaining this interaction. Mutation of these residues abolished Rg3(S)-induced calcium influx, leading to impaired activation of the AMPK-NRF2 pathway and attenuation of the anti-senescence effect of Rg3(S). CONCLUSION: These findings identify ORAI1 as a key molecular mediator of ginsenoside Rg3(S)-induced calcium signaling linked to cellular senescence. By modulating PM-ER contact sites and cytosolic calcium dynamics, Rg3(S) attenuates senescence, providing new mechanistic insight into the anti-aging potential of ginseng-derived compounds beyond autophagy-centered pathways.

Calcium signaling

A Reporter Platform to Study Therapy-Induced Senescence in Live Cancer Cells.

Senescence is a durable state of cell cycle arrest that can be induced by various stressors, including DNA damage caused by chemotherapeutic agents or ionizing radiation. In the context of cancer, therapy-induced senescence (TIS) plays a dual role: while it effectively halts tumor cell proliferation, TIS also carries the risk of promoting tumor relapse through the senescence-associated secretory phenotype (SASP). Beyond its direct impact on tumor cells, cancer therapies leading to TIS often induce short- and long-term side effects that significantly affect the quality of life for patients. However, the lack of universal biomarkers for TIS hinders a comprehensive understanding of its characteristics and its role in cancer therapies. A lamin-based senescence reporter platform is developed to reliably detect and sort live senescent cancer cells. This versatile tool supports live-cell imaging, enabling real-time tracking of senescence induction and escape to investigate heterogeneity in treatment response. Additionally, it allows high-content screening and marker integration, for example incorporating IL6 as SASP marker. It is therefore a valuable tool for fundamental research addressing new questions in the field of TIS as well as for drug discovery, including the development of novel senolytics.

Humans