Senescence-associated Secretory Phenotype Research Articles

Transcriptomic markers of biological aging in breast cancer survivors: a longitudinal study.

The purpose of this study was to examine the impact of breast cancer therapy on biological aging as measured by expression of genes for cellular senescence (p16INK4a, SenMayo), DNA damage response, and proinflammatory senescence-associated secretory phenotype. This longitudinal, observational study evaluated women diagnosed with breast cancer (stage 0-III) prior to radiation therapy (RT) and/or chemotherapy (CT) and at repeated visits out to 2 years. Peripheral blood mononuclear cell gene expression was assessed using RNA sequencing on quality-verified RNA. Longitudinal data were analyzed using mixed linear models and a zero-inflated 2-part model. Women (mean age = 55.5 years) receiving CT with or without RT (n = 73) had higher odds (odds ratio = 2.97, 95% confidence interval = 1.52 to 5.8) of having detectable p16INK4a following treatment compared with RT (n = 76) or surgery alone (n = 37). The proportion of women expressing 16INK4a over the follow-up period increased in all treatment groups (P < .001), with no interaction by treatment. All groups also increased over time in DNA damage response (P < .001), SenMayo (P < .001), and senescence-associated secretory phenotype (P < .001). Groups differed in the pattern of increase over time with statistically significant quadratic time by group differences for CT with or without RT compared with RT alone for DNA damage response (P = .05), SenMayo (P = .006), and the senescence-associated secretory phenotype (P = .02). Results revealed activation of genes associated with biological aging in women with breast cancer from diagnosis through early survivorship, including DNA damage response, cell senescence, and the inflammatory secretome. Increases were evident across cancer treatments, although women receiving CT showed sustained increases, whereas RT exhibited slowing at later time points. Overall, findings suggest that women treated for breast cancer are aging within their immune cells.

Investigation into the significant role of dermal-epidermal interactions in skin ageing utilising a bioengineered skin construct.

Increased prevalence of skin ageing is a growing concern due to an ageing global population and has both sociological and psychological implications. The use of more clinically predictive in vitro methods for dermatological research is becoming commonplace due to initiatives and the cost of clinical testing. In this study, we utilise a well-defined and characterised bioengineered skin construct as a tool to investigate the cellular and molecular dynamics involved in skin ageing from a dermal perspective. Through incorporation of ageing fibroblasts into the dermal compartment we demonstrate the significant impact of dermal-epidermal crosstalk on the overlying epidermal epithelium. We characterise the paracrine nature of dermal-epidermal communication and the impact this has during skin ageing. Soluble factors, such as inflammatory cytokines released as a consequence of senescence associated secretory phenotype (SASP) from ageing fibroblasts, are known to play a pivotal role in skin ageing. Here, we demonstrate their effect on epidermal morphology and thickness, but not keratinocyte differentiation or tissue structure. Through a novel in vitro strategy utilising bioengineered tissue constructs, this study offers a unique reductionist approach to study epidermal and dermal compartments in isolation and tandem.

Morphological and Metabolic Features of Brain Aging in Rodents, Ruminants, Carnivores, and Non-Human Primates

Brain aging in mammals is characterized by morphological and functional changes in neural cells. Macroscopically, this process, leading to progressive cerebral volume loss and functional decline, includes memory and motor neuron deficits, as well as behavioral disorders. Morphologically, brain aging is associated with aged neurons and astrocytes, appearing enlarged and flattened, and expressing enhanced pH-dependent β-galactosidase activity. Multiple mechanisms are considered hallmarks of cellular senescence in vitro, including cell cycle arrest, increased lysosomal activity, telomere shortening, oxidative stress, and DNA damage. The most common markers for senescence identification were identified in (i) proteins implicated in cell cycle arrest, such as p16, p21, and p53, (ii) increased lysosomal mass, and (iii) increased reactive oxygen species (ROS) and senescence-associated secretory phenotype (SASP) expression. Finally, dysfunctional autophagy, a process occurring during aging, contributes to altering brain homeostasis. The brains of mammals can be studied at cellular and subcellular levels to elucidate the mechanisms on the basis of age-related and degenerative disorders. The aim of this review is to summarize and update the most recent knowledge about brain aging through a comparative approach, where similarities and differences in some mammalian species are considered.

Senescent cells promote breast cancer cells motility by secreting GM-CSF and bFGF that activate the JNK signaling pathway

BackgroundCellular senescence can be induced in mammalian tissues by multiple stimuli, including aging, oncogene activation and loss of tumor suppressor genes, and various types of stresses. While senescence is a tumor suppressing mechanism when induced within premalignant or malignant tumor cells, senescent cells can promote cancer development through increased secretion of growth factors, cytokines, chemokines, extracellular matrix, and degradative enzymes, collectively known as senescence-associated secretory phenotype (SASP). Previous studies indicated that senescent cells, through SASP factors, stimulate tumor cell invasion that is a critical step in cancer cell metastasis.MethodsIn the current study, we investigated the effect of senescent cells on the motility of breast cancer cells, which is another key step in cancer cell metastasis. We analyzed the motility of breast cancer cells co-cultured with senescent cells in vitro and metastasis of the breast cancer cells co-injected with senescent cells in orthotopic xenograft models. We also delineated the signaling pathway mediating the effect of senescent cells on cancer cell motility.ResultsOur results indicate that senescent cells stimulated the migration of breast cancer cells through secretion of GM-CSF and bFGF, which in turn induced activation of the JNK pathway in cancer cells. More importantly, senescent cells promoted breast cancer metastasis, with a minimum effect on the primary tumor growth, in orthotopic xenograft mouse models.ConclusionsThese results have revealed an additional mechanism by which senescent cells promote tumor cell metastasis and tumor progression, and will potentially lead to identification of novel targets for cancer therapies that suppress metastasis, the major cause of cancer mortality.

The senolytic agent ABT263 ameliorates osteoporosis caused by active vitamin D insufficiency through selective clearance of senescent skeletal cells

Background/ObjectiveActive vitamin D insufficiency accelerates the development of osteoporosis, with senescent bone cells and the senescence-associated secretory phenotype (SASP) playing crucial roles. This study aimed to investigate whether the senolytic agent ABT263 could correct osteoporosis caused by active vitamin D insufficiency by selectively clearing senescent cells. MethodsBone marrow mesenchymal stem cells (BM-MSCs) from young and aged mice were treated with ABT263 in vitro, and 1,25(OH)2D-insufficient (Cyp27b1+/−) mice were administered ABT263 in vivo. Cellular, molecular, imaging, and histopathological analyses were performed to compare treated cells and mice with control groups. ResultsABT263 induced apoptosis in senescent BM-MSCs by downregulating Bcl2 and upregulating Bax expression. It also induced apoptosis in senescent BM-MSCs from 1,25(OH)2D-insufficient mice. ABT263 administration corrected bone loss caused by 1,25(OH)2D insufficiency by increasing bone density, bone volume, trabecular number, trabecular thickness, and collagen synthesis. It also enhanced osteoblastic bone formation and reduced osteoclastic bone resorption in vivo. ABT263 treatment corrected the impaired osteogenic action of BM-MSCs by promoting their proliferation and osteogenic differentiation. Furthermore, it corrected oxidative stress and DNA damage caused by 1,25(OH)2D insufficiency by increasing SOD-2 and decreasing γ-H2A.X expression. Finally, ABT263 corrected bone cell senescence and SASP caused by 1,25(OH)2D insufficiency by reducing the expression of senescence and SASP-related genes and proteins. ConclusionABT263 can correct osteoporosis caused by active vitamin D insufficiency by selectively clearing senescent skeletal cells, reducing oxidative stress, DNA damage, and SASP, and promoting bone formation while inhibiting bone resorption. These findings provide new insights into the potential therapeutic application of senolytic agents in the treatment of osteoporosis associated with active vitamin D insufficiency. The translational potential of this articleThis study highlights the therapeutic potential of ABT263, a senolytic compound, in treating osteoporosis caused by active vitamin D insufficiency. By selectively eliminating senescent bone cells and their associated SASP, ABT263 intervention demonstrates the ability to restore bone homeostasis, prevent further bone loss, and promote bone formation. These findings contribute to the growing body of research supporting the use of senolytic therapies for the prevention and treatment of age-related bone disorders. The translational potential of this study lies in the development of novel therapeutic strategies targeting cellular senescence to combat osteoporosis, particularly in cases where vitamin D insufficiency is a contributing factor. Further clinical studies are warranted to validate the efficacy and safety of ABT263 and other senolytic agents in the treatment of osteoporosis in humans.

7581 Periodic Administration of Quercetin and Dasatinib Alleviates Skeletal Fragility in the INS2AKITA Mouse Model of Type 1 Diabetes

Abstract Disclosure: R. Dresner-Pollak: Consulting Fee; Self; Opko Biologics LTD.. Speaker; Self; Medison Pharma. N. Lishinsky: None. I. Gurt: None. J. Stokar: None. V. Temkin: None. P. Shivam: None. G. Zatarah: None. J. Milgram: None. R. Shahar: None. Skeletal fragility is a recognized complication of type 1 diabetes (T1D). The risk of hip and non-vertebral fractures is significantly higher in people living with T1D compared to age- and sex-matched non-diabetic controls and those living with type 2 diabetes (T2D). Hip fracture risk is up to six-fold higher in T1D patients; hip fractures occur 10-15 years earlier and the outcome is poorer compared to non-diabetics. Alterations in bone quality are considered major contributors to T1D-related skeletal fragility. As people with T1D live longer, there is a growing need to discover new therapeutics to reduce fracture risk. TID is associated with accelerated biological aging. Cellular senescence is a fundamental mechanism of aging. Senescent cells stop dividing, are resistant to apoptosis and acquire a distinct phenotype that includes secretome changes termed “senescence-associated secretory phenotype” (SASP). Clearing senescent cells with senolytics is recognized as a promising therapeutic approach for multiple conditions in mice and humans We explored the ability of senolytics dasatinib (D), a tyrosine kinase inhibitor, and quercetin (Q), a flavanol, present in fruit and vegetables, drug combination, to alleviate femur fragility in mice with T1D. Ins2Akita mice show a sexual dimorphic effect of the mutant Ins2 allele causing severe hyperglycemia in males. We treated Ins2Akita male and female mice and C57BL/6 wild type (WT) male mice with D + Q administered once monthly for four months beginning at age 3 months. 3-month-old Ins2Akita male mice had higher blood levels of the SASPs components HMGB1, PAI-1, MMP12, and increased gene expression of p53 and senescence effectors p16, p15 and SASPs Il1b, Mmp3, Mmp9, Mmp13, Serpineb2 at the femur diaphysis and in bone marrow mesenchymal stem cells, respectively compared to age-matched WT male mice. In vitro, exposure to glucose levels equivalent to those observed in blood in Ins2Akita male mice induced cellular senescence in IDG-SW3 osteocyte-like cells including a 4-5-fold increase in gene expression of p16INK4a, p21Cip[1], p53, double percentage of SA-β-gal+ cells and P21 protein level. Ingenuity pathway analysis of differentially expressed proteins revealed enrichment for the senescence pathway (Z=1.213; P=1.11E-05). D+Q administration did not affect bone microarchitecture at the spine (L2), distal femur metaphysis and diaphysis assessed by µCT. D+Q administration significantly increased femur resistance to fracture assessed by the 3-point-bending test by increasing whole femur work-to-fracture, the ultimate parameter of bone resistance to failure, and post-yield displacement, an index of matrix composition, organization, and bone quality in Ins2Akita males. No effect was observed in Ins2Akita females or WT male mice, indicating that the intervention is specific for T1D. Senolyitcs D+Q show promise in improving bone health in T1D. Presentation: 6/1/2024

12489 Senolytics Dasatinib And Quercetin Alleviate Type 1 Diabetes-Related Cardiac Fibrosis In Male Akita Ins-/+Mice

Abstract Disclosure: N. Kadoumi: None. G. Zatarah: None. J. Stokar: None. P. Shivam: None. I. Gurt: None. R. Dresner-Pollak: None. People living with type 1 diabetes (T1D) have a markedly shorter life expectancy compared to non-diabetic age- and sex-matched controls primarily due to cardiovascular disease. Diabetic cardiomyopathy is characterized by structural and functional alterations that occur independently of hypertension or coronary artery leading to congestive heart failure. The pathogenesis of diabetic cardiomyopathy involves endothelial cell dysfunction, microangiopathy, mitochondrial dysfunction, and oxidative stress, resulting in inflammation, extensive remodeling, cardiomyocyte hypertrophy, interstitial fibrosis, and apoptosis. T1D is associated with accelerated aging. Cellular senescence is a hallmark of aging, it is characterized by cell cycle arrest, distinct morphological alterations and the release of molecules referred to as the senescence-associated secretory phenotype (SASP). Senescent cardiomyocytes secrete SASPs that promote activation of fibroblasts, hypertrophy of cardiac muscle cells, and dysfunction of cardiac endothelial cells. An increase in cardiac cellular senescence was demonstrated in mouse models of T1D. Senolytics are compounds that clear senescent cells. Senolytics were shown to improve multiple outcomes in age-associated conditions in mice and humans.We investigated the effects of senolytics Dasatinib (D) and Quercetin (Q) on cardiac fibrosis in the AKITA Ins-/+ mouse model of T1D.We first assessed if there is increased collagen type1 expression in the heart ventricles and perivascular in 3-month-old in AKITA Ins-/+ vs. WT male mice using Immunofluorescence. Increased perivascular and interstitial expression of collagen 1 was found in AKITA Ins-/+ compared to WT age-and sex-matched mice (0.0811±0.008177 µm2 vs. 0.0533± 0.007960 µm2 ,P=0.0476), (105.7±10.29 µm2 vs. 54.85±14.61 µm2, P=0.0476), respectively. Next, 3-month-old AKITA Ins-/+wmale mice were randomly assigned to treatment with Dasatinib (5 mg/kg) and Quercetin (50 mg/kg) or vehicle administered once monthly by oral gavage for a total of four months (n=20, 10 in each group). Heart samples were analyzed for gene expression, collagen 1 protein by western blotting and Immunofluorescence and analyzed using QuPath 0.5.0 Software. Interstitial and perivascular fibrosis was separately assessed in the right and left ventricles. Treatment with D+Q resulted in a 2-fold decrease in COL1A1 gene and Collagen 1 protein expression by RT-PCR and western blot analysis (P= 0.011 and 0.042, respectively) in AKITA Ins-/+ mice. Immunostaining analysis revealed reduced Collagen 1 deposition in both the left and right ventricles (105.7±10.29 µm2 vs. 43.53±16.31 µm2, P=0.0571), as well as in the perivascular area (0.0811±0.008177 µm2 vs. 0.052±0.006163 µm2, P=0.1143). Treatment with senolytics D+Q reduces the expression of Collagen I, a key factor in myocardial fibrosis, in adult male AKITA Ins-/+ mice. Presentation: 6/3/2024

RNA Sequencing Analysis of Monocytes Exposed to Airway Fluid From Children With Pediatric Acute Respiratory Distress Syndrome.

Monocytes are plastic cells that assume different polarization states that can either promote inflammation or tissue repair and inflammation resolution. Polarized monocytes are partially defined by their transcriptional profiles that are influenced by environmental stimuli. The airway monocyte response in pediatric acute respiratory distress syndrome (PARDS) is undefined. To identify differentially expressed genes and networks using a novel transcriptomic reporter assay with donor monocytes exposed to the airway fluid of intubated children with and at-risk for PARDS. To determine differences in gene expression at two time points using the donor monocyte assay exposed to airway fluid from intubated children with PARDS obtained 48-96 hours following initial tracheal aspirate sampling. In vitro pilot study carried out using airway fluid supernatant. Academic 40-bed PICU. Fifty-seven children: 44 children with PARDS and 13 children at-risk for PARDS. None. We performed bulk RNA sequencing using a transcriptomic reporter assay of monocytes exposed to airway fluid from intubated children to discover gene networks differentiating PARDS from at-risk for PARDS and those differentiating mild/moderate from severe PARDS. We also report differences in gene expression in children with PARDS 48-96 hours following initial tracheal aspirate sampling. We found that interleukin (IL)-10, IL-4, and IL-13, cytokine/chemokine signaling, and the senescence-associated secretory phenotype are upregulated in monocytes exposed to airway fluid from intubated children with PARDS compared with those at-risk for PARDS. Signaling by NOTCH, histone deacetylation/acetylation, DNA methylation, chromatin modifications (B-WICH complex), and RNA polymerase I transcription and its associated regulatory apparatus were upregulated in children with PARDS 48-96 hours following initial tracheal aspirate sampling. We identified gene networks important to the PARDS airway immune response using bulk RNA sequencing from a monocyte reporter assay that exposed monocytes to airway fluid from intubated children with and at-risk for PARDS. Mechanistic investigations are needed to validate our findings.

The Neolignan Honokiol and Its Synthetic Derivative Honokiol Hexafluoro Reduce Neuroinflammation and Cellular Senescence in Microglia Cells

Microglia-mediated neuroinflammation has been linked to neurodegenerative disorders. Inflammation and aging contribute to microglial senescence. Microglial senescence promotes the development of neurodegenerative disorders, including Alzheimer’s disease (AD). In this study, we investigated the anti-neuroinflammatory and anti-senescence activity of Honokiol (HNK), a polyphenolic neolignane from Magnolia officinalis Rehder &amp; E.H Wilson, in comparison with its synthetic analogue Honokiol Hexafluoro (CH). HNK reduced the pro-inflammatory cell morphology of LPS-stimulated BV2 microglia cells and increased the expression of the anti-inflammatory cytokine IL-10 with an efficacy comparable to CH. HNK and CH were also able to attenuate the alterations in cell morphology associated with cellular senescence in BV2 cells intermittently stimulated with LPS and significantly reduce the activity and expression of the senescence marker ß-galactosidase and the expression of p21 and pERK1/2. The treatments reduced the expression of senescence-associated secretory phenotype (SASP) factors IL-1ß and NF-kB, decreased ROS production, and abolished H2AX over phosphorylation (γ-H2AX) and acetylated H3 overexpression. Senescent microglia cells showed an increased expression of the Notch ligand Jagged1 that was reduced by HNK and CH with a comparable efficacy to the Notch inhibitor DAPT. Overall, our data illustrate a protective activity of HNK and CH on neuroinflammation and cellular senescence in microglia cells involving a Notch-signaling-mediated mechanism and suggesting a potential therapeutic contribution in aging-related neurodegenerative diseases.

The Punicalagin Compound Mitigates Bronchial Epithelial Cell Senescence Induced by Cigarette Smoke Extract through the PAR2/mTOR Pathway.

Tobacco smoke is an important inducer of airway epithelial cell aging. Punicalagin(PCG) is a natural anti-aging compound. The effect of PCG on tobacco smoke-induced airway epithelial cell senescence is unknown. Our study investigated whether PCG can treat the human bronchial epithelial cell line (BEAS-2B) aging by inhibiting the protease-activated receptor 2 (PAR2)/m- TOR pathway. Bioinformatics techniques were used to analyze the potential biological functions of PAR2. Molecular dynamics evaluated the binding ability of PCG and PAR2. The CCK8 assay was used to detect the cytotoxicity of CSE and PCG. The activity of the PAR2/mTOR pathway and the expression of the characteristic aging markers p16, p21, and SIRT1 are detected by qRT-PCR and Western blotting. Cell senescence was observed by Senescence-associated β-galactosidase (SA-β-gal) staining. The senescence-associated secretory phenotype (SASP): concentrations of interleukin IL-6, IL-8, and TNF- α were detected by ELISA. The GSE57148 bioinformatics analysis dataset showed that PAR2 regulates lung senescence through the mTOR signaling pathway. Molecular dynamics results found that PCG and PAR2 had a strong and stable binding force. CSE induces BEAS-2B cell senescence and activates the PAR2/mTOR pathway. Inhibition of PAR2 mitigated the senescence changes. In addition, PCG's pretreatment can significantly alleviate CSE-induced BEAS-2B cell senescence while inhibiting the PAR2/mTOR pathway. PCG has a therapeutic effect on the senescence of airway epithelial cells.

A new model and precious tool to study molecular mechanisms of macrophage aging.

The accumulation of senescent cells, characterized by a senescence-associated secretory phenotype (SASP), contributes to chronic inflammation and age-related diseases (ARD). During aging, macrophages can adopt a senescent-like phenotype and an altered function, which promotes senescent cell accumulation. In the context of aging and ARD, controlling the resolution of the inflammatory response and preventing chronic inflammation, especially by targeting macrophages, must be a priority. Aging being a dynamic process, we developed a model of in vitro murine peritoneal macrophage aging. Our results show that macrophages cultured for 7 or 14 days exhibit a senescence-like phenotype: proliferation decrease, the levels of cyclin-dependent kinase inhibitors p16INK4A and p21CIP1 and of pro-inflammatory SASP components (MCP-1, IL-6, IL-1β, TNF-α, and MMP-9) increase, phagocytosis capacity decline and glycolytic activity is induced. In our model, chronic treatment with CB3, a thioredoxin-1 mimetic anti-inflammatory peptide, completely prevents p21CIP1 increase and enables day 14 macrophages to maintain proliferative activity.We describe a new model of macrophage aging with a senescence-like phenotype associated with inflammatory, metabolic and functional perturbations. This model is a valuable tool for characterizing macrophage aging mechanisms and developing innovative strategies with promising therapeutical purpose in limiting inflammaging and ARD.

Fisetin as a Senotherapeutic Agent: Evidence and Perspectives for Age-Related Diseases

Fisetin, a flavonoid naturally occurring in plants, fruits, and vegetables, has recently gained attention for its potential role as a senotherapeutic agent for the treatment of age-related chronic diseases. Senotherapeutics target senescent cells, which accumulate with age and disease, in both circulating immune cell populations and solid organs and tissues. Senescent cells contribute to development of many chronic diseases, primarily by eliciting systemic chronic inflammation through their senescence-associated secretory phenotype. Here, we explore whether fisetin as a senotherapeutic can eliminate senescent cells, and thereby alleviate chronic diseases, by examining current evidence from in vitro studies and animal models that investigate fisetin’s impact on age-related diseases, as well as from phase I/II trials in various patient populations. We discuss the application of fisetin in humans, including challenges and future directions. Our review of available data suggests that targeting senescent cells with fisetin offers a promising strategy for managing multiple chronic diseases, potentially transforming future healthcare for older and multimorbid patients. However, further studies are needed to establish the safety, pharmacokinetics, and efficacy of fisetin as a senotherapeutic, identify relevant and reliable outcome measures in human trials, optimize dosing, and better understand the possible limitations of fisetin as a senotherapeutic agent.

In vitro treatment with Metformin significantly reduces senescent B cells present in the adipose tissue of people with obesity

BackgroundOur previous work has shown that senescent B cells accumulate in the human adipose tissue (AT) from people with obesity, where they express transcripts for markers associated with the senescence-associated secretory phenotype (SASP) and secrete multiple inflammatory mediators. These functions of AT-derived B cells are metabolically supported. ObjectiveTo show that Metformin (MET), a widely used hypo-glycemic and anti-diabetic drug, is able at least in vitro to decrease frequencies, secretory profile and metabolic requirements of senescent B cells isolated from the AT from people with obesity. MethodsWe recruited adult females with obesity (n=8, age 40±2 years, BMI range 33-42) undergoing breast reduction surgery, who donated their discarded subcutaneous AT. B cells from stromal vascular fractions (SVFs) isolated after collagenase digestion of the AT were evaluated after in vitro incubation with MET (1 mMx106 B cells) or with medium for the following measures. Expression of trascripts for SASP-associated markers (p16INK4a and p21CIP1/WAF1) measured by qPCR; secretion of inflammatory cytokines (TNF-α, IL-6, IFN-γ and IL-17A) measured by a Cytometric Bead Array); metabolic characteristics as identified by a glycolytic test and Seahorse technology, as well as by the expression of transcripts for glucose transporters and metabolic enzymes involved in glucose metabolic pathways, measured by qPCR. To examine differences between MET-treated versus untreated groups, paired Student’s t tests (two-tailed) were employed. ResultsMET in vitro was able to reduce frequencies and numbers of senescent B cells, as identified by staining with β-galactosidase, as well as the secretion of inflammatory cytokines, the expression of transcripts for SASP and metabolic markers that support intrinsic B cell inflammation. ConclusionsOur results provide evidence to support the beneficial effects of MET in reducing AT-related inflammation through its effects on senescent B cells.

METTL3-regulated m6A modification of lncRNA E230001N04Rik is involved in myofibroblast differentiation in arsenic-induced pulmonary fibrosis through promoting senescence of lung epithelial cells

Arsenic is a toxic agent that causes respiratory damage. Long non-coding RNAs (lncRNAs) are non-coding transcripts that adsorb specific miRNAs and regulate biological processes of human diseases. N6-Methyladenosine (m6A) is an internal modification of RNAs. However, there are few reports about lncRNAs and m6A modifications as co-regulators of pulmonary fibrosis. For 6 months, C57BL/6 mice were given water containing 0, 10, or 20 ppm arsenite. meRIP-seq and lncRNA-seq analyses showed that the m6A levels of the lncRNA E230001N04Rik were higher, and the levels of E230001N04Rik itself were lower in the high-dose arsenite group than in the controls. Murine lung epithelial 12 (MLE12) cells, exposed to 8μM arsenite for 8 passages, had elevated METTL3 and miR-20b-3p and low E230001N04Rik. Arsenite induced cellular senescence, as demonstrated by secretion of factors related to the senescence-associated secretory phenotype (SASP). Arsenite-treated MLE12 cells co-cultured with primary lung fibroblasts (PLFs) caused myofibroblast differentiation. These data show that METTL3 reduces E230001N04Rik expression via controlling its m6A levels, which regulate miR-20b-3p and mediate the senescence of alveolar epithelial cells (AECs). Thereby, E230001N04Rik is involved in the arsenite-induced myofibroblast differentiation and in pulmonary fibrosis. These observations provide a prospective mechanism for chronic pulmonary disease caused by arsenite.

Targeted apoptosis of senescent cells by valproic acid alleviates therapy-induced cellular senescence and lung aging

BackgroundAccumulation of senescent cells in tissues and their downstream effect programs have emerged as key drivers of aging and age-associated pathologies. Recent progresses in senotherapeutics indicated that either selectively killing senescent cells with senolytics or suppressing the senescence-associated secretory phenotype (SASP) secretion using senomorphics contributes to extending of the healthy lifespan and alleviating numerous age-related disorders in mice. PurposeHowever, the potential side-effects and long-term cytotoxicity of the above novel compounds have not yet been determined. Therefore, it seems to be more efficient to explore new senotherapeutical functions from approved drugs. MethodsThe effects of valproic acid (VPA), a derivative of valine, in cellular senescence were evaluated by senescence-associated β galactosidase (SA-β-Gal) staining, flow cytometry and western blot (WB). The cell viability was tested using CCK-8 kits. Cell apoptosis was detected by Annexin V-EGFP/PI apoptosis detection kit. Cell autophagy was checked using GFP-RFP-LC3 ratiometric plasmid. The roles of VPA in lung aging were investigated by in vivo experiments using H&E and Masson staining, WB, as well as electronic microscope strategies. ResultsHere we identified VPA was able to induce an over-accumulation of reactive oxygen species (ROS) (>1.5 times increasing) and apoptosis (>2 times increasing) of senescent cells. Mechanistically, VPA activated the phospholipid modifying enzyme membrane-bound O-acyltransferase domain-containing protein 1 (MBOAT1), which was repressed during senescence, then promoted mitochondrial autophagy and apoptosis. In addition, VPA was also found to alleviate therapy induced abnormal mitochondria and lung aging phenotype (>1.5 times decreasing of lung fibrosis markers and >2.5 times increasing of naïve/memory CD4+ or CD8+ cells) in vivo. ConclusionTaken together, our study demonstrated that VPA was able to selectively killing senescent cells both in vitro and in vivo, and thus shedding light on new functions and novel potential application of VPA in anti-aging and anti-age-associated diseases.

RNA m6A methylation regulatory mechanism of resveratrol in premature senescence cells

AbstractResveratrol, a natural compound found in various plants, is known for its anti‐inflammatory, antioxidant, and senescence‐delaying properties. RNA N6‐methyladenosine (m6A) methylation plays a crucial role in oxidative stress and premature cellular senescence processes and is closely associated with age‐related disorders. However, the anti‐premature senescence via RNA m6A methylation mechanism of resveratrol is still not fully understood. In this study, based on premature senescence model of human embryonic lung fibroblasts (HEFs) induced by hydrogen peroxide (H2O2), a widely accepted model of premature senescence caused by oxidative stress, we explored the anti‐aging regulatory effects of resveratrol at the RNA m6A methylation level. Our data suggested that resveratrol significantly delayed premature senescence by increasing cell viability, reducing SA‐β‐gal blue staining rate, ROS levels, and senescence‐associated secretory phenotypes (SASP) expression in HEFs. Meanwhile, resveratrol increased the whole RNA methyltransferases activity and the overall m6A level during senescence. Furthermore, three genes CCND2, E2F1, and GADD45B have been identified as the main ones regulating premature by resveratrol. Specifically, it decreased E2F1, GADD45B RNA m6A methylation level, and increased CCND2 level in premature cells. Our study provided new clues for exploring the mechanism and application of resveratrol in the field of premature aging.

Therapeutic targeting of senescent cells in the CNS.

Senescent cells accumulate throughout the body with advanced age, diseases and chronic conditions. They negatively impact health and function of multiple systems, including the central nervous system (CNS). Therapies that target senescent cells, broadly referred to as senotherapeutics, recently emerged as potentially important treatment strategies for the CNS. Promising therapeutic approaches involve clearing senescent cells by disarming their pro-survival pathways with 'senolytics'; or dampening their toxic senescence-associated secretory phenotype (SASP) using 'senomorphics'. Following the pioneering discovery of first-generation senolytics dasatinib and quercetin, dozens of additional therapies have been identified, and several promising targets are under investigation. Although potentially transformative, senotherapies are still in early stages and require thorough testing to ensure reliable target engagement, specificity, safety and efficacy. The limited brain penetrance and potential toxic side effects of CNS-acting senotherapeutics pose challenges for drug development and translation to the clinic. This Review assesses the potential impact of senotherapeutics for neurological conditions by summarizing preclinical evidence, innovative methods for target and biomarker identification, academic and industry drug development pipelines and progress in clinical trials.

Systemic comparison of molecular characteristics in different skin fibroblast senescent models.

Senescent human skin primary fibroblast (FB) models have been established for studying aging-related, proliferative, and inflammatory skin diseases. The aim of this study was to compare the transcriptome characteristics of human primary dermal FBs from children and the elderly with four senescence models. Human skin primary FBs were obtained from healthy children (FB-C) and elderly donors (FB-E). Senescence models were generated by ultraviolet B irradiation (FB-UVB), D-galactose stimulation (FB-D-gal), atazanavir treatment (FB-ATV), and replication exhaustion induction (FB-P30). Flow cytometry, immunofluorescence staining, real-time quantitative polymerase chain reaction, co-culturing with immune cells, and bulk RNA sequencing were used for systematic comparisons of the models. In comparison with FB-C, FB-E showed elevated expression of senescence-related genes related to the skin barrier and extracellular matrix, proinflammatory factors, chemokines, oxidative stress, and complement factors. In comparison with FB-E, FB-UVB and FB-ATV showed higher levels of senescence and expression of the genes related to the senescence-associated secretory phenotype (SASP), and their shaped immune microenvironment highly facilitated the activation of downstream immune cells, including T cells, macrophages, and natural killer cells. FB-P30 was most similar to FB-E in terms of general transcriptome features, such as FB migration and proliferation, and aging-related characteristics. FB-D-gal showed the lowest expression levels of senescence-related genes. In comparisons with the single-cell RNA sequencing results, FB-E showed almost complete simulation of the transcriptional spectrum of FBs in elderly patients with atopic dermatitis, followed by FB-P30 and FB-UVB. FB-E and FB-P30showed higher similarity with the FBs in keloids. Each senescent FB model exhibited different characteristics. In addition to showing upregulated expression of natural senescence features, FB-UVB and FB-ATV showed high expression levels of senescence-related genes, including those involved in the SASP, and FB-P30showed the greatest similarity with FB-E. However, D-galactose-stimulated FBs did not clearly present aging characteristics.

MiR-96-5p expression is sufficient to induce and maintain the senescent cell fate in the absence of stress

Senescence is a cell fate driven by different types of stress that results in exit from the cell cycle and expression of an inflammatory senescence-associated secretory phenotype (SASP). Here, we demonstrate that stable overexpression of miR-96-5p was sufficient to induce cellular senescence in the absence of genotoxic stress, inducing expression of certain markers of early senescence including SASP factors while repressing markers of deep senescence including LINE-1 and type 1 interferons. Stable miR-96-5p overexpression led to genome-wide changes in heterochromatin followed by epigenetic activation of p16Ink4a, p21Cip1, and SASP expression, induction of a marker of DNA damage, and induction of a transcriptional signature similar to other senescent lung and endothelial cell types. Expression of miR-96-5p significantly increased following senescence induction in culture cells and with aging in tissues from naturally aged and Ercc1-/Δ progeroid mice. Mechanistically, miR-96-5p directly suppressed expression of SIN3B and SIN3 corepressor complex constituents KDM5A and MORF4L2, and siRNA-mediated knockdown of these transcriptional regulators recapitulated the senescent phenotype. In addition, pharmacologic inhibition of the SIN3 complex suppressed senescence and SASP markers. These results clearly demonstrate that a single microRNA is sufficient to drive early senescence in the absence of genotoxic stress through targeting epigenetic and transcriptional regulators, identifying novel targets for the development of senotherapeutics.

The potential of flavonoids to mitigate cellular senescence in cardiovascular disease.

Aging is one of the most significant factors affecting cardiovascular health, with cellular senescence being a central hallmark. Senescent cells (SCs) secrete a specific set of signaling molecules known as the senescence-associated secretory phenotype (SASP). The SASP has a remarkable impact on age-associated diseases, particularly cardiovascular diseases (CVD). Targeting SCs through anti-aging therapies represents a novel strategy to effectively retard senescence and attenuate disease progression. Accumulating evidence demonstrates that the flavonoids, widely presented in fruits and vegetables worldwide, can delay or treat CVD via selectively eliminating SCs (senolytics) and modulating SASPs (senomorphics). Nevertheless, only sporadic research has illustrated the application of flavonoids in targeting SCs for CVD, which requires further exploration. This review recapitulates the hallmarks and key molecular mechanisms involved in cellular senescence, then summarizes senescence of different types of cardiac cells and describes the mechanisms by which cellular senescence affects CVD development. The discussion culminates with the potential use of flavonoids via exerting their biological effects on cellular senescence to reduce CVD incidence. This summary will provide valuable insights for cardiovascular drug design, development and clinical applications leveraging flavonoids.