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BackgroundEpigenetic changes link medical, social, and environmental factors with cardiovascular and kidney disease and, more recently, with cancer. The mechanistic link between metabolic health and epigenetic changes is only starting to be investigated. In our in vitro and in vivo studies, we performed a broad analysis of the link between hyperinsulinemia and chromatin acetylation; our top "hit" was chromatin opening at H3K9ac.MethodsBuilding on our published preclinical studies, here, we performed a detailed analysis of the link between insulin resistance, chromatin acetylation, and inflammation using an initial test set of 28 women and validation sets of 245, 22, and 53 women.ResultsChIP-seq identified chromatin acetylation and opening at the genes coding for TNFα and IL6 in insulin-resistant women. Pathway analysis identified inflammatory response genes, NFκB/TNFα-signaling, reactome cytokine signaling, innate immunity, and senescence. Consistent with this finding, flow cytometry identified increased senescent circulating peripheral T-cells. DNA methylation analysis identified evidence of accelerated aging in insulin-resistant vs. metabolically healthy women.ConclusionsThis study shows that insulin-resistant women have increased chromatin acetylation/opening, inflammation, and, perhaps, accelerated aging. Given the role that inflammation plays in cancer initiation and progression, these studies provide a potential mechanistic link between insulin resistance and cancer.

Senescence is a state of indefinite cell-cycle arrest associated with aging, cancer, and age-related diseases. Here, we find that translational deregulation, together with a corresponding maladaptive integrated stress response (ISR), is a hallmark of senescence that desensitizes senescent cells to stress. We present evidence that senescent cells maintain high levels of eIF2α phosphorylation, typical of ISR activation, but translationally repress production of the stress response activating transcription factor 4 (ATF4) by ineffective bypass of the inhibitory upstream open reading frames (uORFs). Surprisingly, ATF4 translation remains inhibited even after acute proteotoxic and amino acid starvation stressors, resulting in a highly diminished stress response. We also find that stress augments the senescence-associated secretory phenotype with sustained remodeling of inflammatory factors expression that is suppressed by non-uORF carrying ATF4 mRNA expression. Our results thus show that senescent cells possess a unique response to stress, which entails an increase in their inflammatory profile. [Display omitted] • Senescent cells have basal levels of eIF2α phosphorylation without ATF4 expression • Senescence is accompanied by a global decrease in ribosome content • Reduced ribosome content suppresses the ability of stress to activate the ISR • Acute stress modulates the SASP up to days after the stress has been removed Payea et al. find that ribosome depletion associated with senescence suppresses the integrated stress response (ISR) and leads to transcriptional remodeling of the senescence secretome. Stress-induced secretory remodeling (SSR) lasts days after the initial stress is removed and is suppressed by reactivation of the ISR. [ABSTRACT FROM AUTHOR]

Upregulation of nuclear factor κB (NFκB) signaling is a hallmark of aging and a major cause of age‐related chronic inflammation. However, its effect on cellular senescence remains unclear. Here, we show that alteration of NFκB nuclear dynamics from oscillatory to sustained by depleting a negative feedback regulator of NFκB pathway, NFκB inhibitor alpha (IκBα), in the presence of tumor necrosis factor α (TNFα) promotes cellular senescence. Sustained NFκB activity enhanced inflammatory gene expression through increased NFκB‐DNA binding and slowed the cell cycle. IκBα protein was decreased under replicative or oxidative stress in vitro. Furthermore, a decrease in IκBα protein and an increase in DNA‐NFκB binding at the transcription start sites of age‐associated genes in aged mouse hearts suggested that nuclear NFκB dynamics may play a critical role in the progression of aging. Our study suggests that nuclear NFκB dynamics‐dependent epigenetic changes regulated over time in a living system, possibly through a decrease in IκBα, enhance the expression of inflammatory genes to advance the cells to a senescent state. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Senescence, caused by cell‐cycle arrest, is a hallmark of aging. Senescence has also been described in embryogenesis, wound healing, and acute injuries. Sepsis is characterized by a dysregulated host response to infection, leading to organ dysfunction and mortality. Most of the pathophysiology of human sepsis is recapitulated in the mouse model of polymicrobial sepsis, developed by cecal ligation and puncture (CLP). In this report, we demonstrate a rapid onset of cellular senescence in the liver of mice subjected to CLP‐induced sepsis, characterized by the upregulation of p21, p53, and other senescence markers, including SA‐βgal. Using RNAscope, confocal microscopy, and flow cytometry, we further confirm the emergence of p21‐expressing senescence phenotype in the liver 24 h after sepsis induction. Senescence was observed in several cell types in the liver, including hepatocytes, endothelial cells, and macrophages. We determined the landscape of senescence phenotype in murine sepsis by single‐cell sequencing, which further ascertained that this cell fate is not confined to any particular cell type but displays a heterogeneous distribution. Furthermore, we observed a significant reduction in mortality following sepsis when mice were treated with senolytics, a combination of dasatinib and quercetin, before the CLP surgery. Our experiments unequivocally demonstrated a rapid development of cellular senescence with sepsis and, for the first time, described the senescence landscape in the sepsis liver and the possible role of senescent cells in the worsening outcome following sepsis. [ABSTRACT FROM AUTHOR]

The integrated behaviour of multiple senescent cell types within a single human tissue leading to the development of malignancy is unclear. Patients with Familial Melanoma Syndrome (FMS) have heterozygous germline defects in the CDKN2A gene coding for the cyclin inhibitor p16INK4a. Melanocytes within skin biopsies from FMS patients express significantly less p16INK4a but express higher levels of the DNA‐damage protein 훾H2AX a than fibroblastic cells. However, patient fibroblasts also exhibit defects since senescent cells do not increase in the skin during ageing and fibroblasts isolated from the skin of patients have increased replicative capacity compared to control fibroblasts in vitro, culminating in abnormal nuclear morphology. Patient derived fibroblasts also secreted less SASP than control cells. Predisposition of FMS patients to melanoma may therefore result from integrated dysregulation of senescence in multiple cell types in vivo. The inherently greater levels of DNA damage and the overdependence of melanocytes on p16 for cell cycle inhibition after DNA damage makes them exquisitely susceptible to malignant transformation. This may be accentuated by senescence‐related defects in fibroblasts, in particular reduced SASP secretion that hinders recruitment of T cells in the steady state and thus reduces cutaneous immunosurveillance in vivo. [ABSTRACT FROM AUTHOR]

Multiple changes occur in hormonal regulation with aging and across various endocrine organs. These changes are associated with multiple age-related disorders and diseases. A better understanding of responsible underling biological mechanisms could help in the management of multiple endocrine disorders over and above hormone replacement therapy (HRT). Cellular senescence is involved in multiple biological aging processes and pathologies common in elderly individuals. Cellular senescence, which occurs in many older individuals but also across the lifespan in association with tissue damage, acute and chronic diseases, certain drugs, and genetic syndromes, may contribute to such endocrine disorders as osteoporosis, metabolic syndrome, and type 2 diabetes mellitus. Drugs that selectively induce senescent cell removal, "senolytics,", and drugs that attenuate the tissue-destructive secretory state of certain senescent cells, "senomorphics," appear to delay the onset of or alleviate multiple diseases, including but not limited to endocrine disorders such as diabetes, complications of obesity, age-related osteoporosis, and cancers as well as atherosclerosis, chronic kidney disease, neurodegenerative disorders, and many others. More than 30 clinical trials of senolytic and senomorphic agents have already been completed, are underway, or are planned for a variety of indications. Targeting senescent cells is a novel strategy that is distinct from conventional therapies such as HRT, and thus might address unmet medical needs and can potentially amplify effects of established endocrine drug regimens, perhaps allowing for dose decreases and reducing side effects. [ABSTRACT FROM AUTHOR]

Doxorubicin (Dox), an anthracycline antibiotic, is widely used in cancer treatment. Although its antitumor efficacy appears significant, its clinical use is greatly restricted by its induction of cardiotoxicity. Cardiac senescence drives the Dox‐induced cardiotoxicity, but whether diminishing these senescent cardiomyocytes could alleviate the cardiotoxicity remains unclear. Here, we assessed whether senescent cardiomyocytes have a senescence‐associated secretory phenotype (SASP) that affects healthy non‐senescent cardiomyocytes, rendering them senescent via the delivery of exosomes. Additionally, we explored whether targeting SASP senescent cardiomyocytes using a Bcl‐2 inhibitor could alleviate cardiotoxicity. Cardiac damage was induced in a mouse model of continuous Dox treatment in vivo, and cardiomyocytes in vitro. Immunofluorescence of the senescence markers of Cdkn2a, Cdkn1a and γ‐H2A.X was used to assess the SASP in the Dox‐treated heart. To explore the molecular mechanisms involved, the Bcl‐2 inhibitor ABT‐199 was employed to eliminate SASP senescent cardiomyocytes. We show that the cardiomyocytes acquire a SASP during Dox treatment. The senescent cardiomyocytes upregulated Bcl‐2, although treatment of mice with ABT‐199 selectively eliminated SASP senescent cardiomyocytes involved in Dox‐induced cardiotoxicity, thus leading to partial alleviation of Dox‐induced cardiotoxicity. Moreover, we concluded that SASP factors secreted by senescent cardiomyocytes induced by Dox renders otherwise healthy cardiomyocytes senescent through exosome delivery. Our findings suggest that SASP senescent cardiomyocytes are a significant component of the pathogenesis of Dox‐dependent cardiotoxicity and indicate that targeting the clearance of SASP senescent cardiomyocytes could be a new therapeutic approach for Dox‐induced cardiac injury. [ABSTRACT FROM AUTHOR]

Background: Pulmonary fibrosis (PF) is an aging-related progressive lung disorder. The aged lung undergoes functional and structural changes termed immunosenescence and inflammaging, which facilitate the occurrence of fibrosis. Interleukin-10 (IL-10) is a potent anti-inflammatory and immunoregulatory cytokine, yet it remains unclear how IL-10 deficiency-induced immunosenescence participates in the development of PF. Methods: Firstly we evaluated the susceptibility to fibrosis and IL-10 expression in aged mice. Then 13-month-old wild-type (WT) and IL-10 knockout (KO) mice were subjected to bleomycin(BLM) and analyzed senescence-related markers by PCR, western blot and immunohistochemistry staining of p16, p21, p53, as well as DHE and SA-β-gal staining. We further compared 18-month-old WT mice with 13-month-old IL-10KO mice to assess aging-associated cell senescence and inflamation infiltration in both lung and BALF. Moreover, proliferation and apoptosis of alveolar type 2 cells(AT2) were evaluated by FCM, immunofluorescence, TUNEL staining, and TEM analysis. Recombinant IL-10 (rIL-10) was also administered intratracheally to evaluate its therapeutic potential and related mechanism. For the in vitro experiments, 10-week-old naïve pramily lung fibroblasts(PLFs) were treated with the culture medium of 13-month PLFs derived from WT, IL-10KO, or IL-10KO + rIL-10 respectively, and examined the secretion of senescence-associated secretory phenotype (SASP) factors and related pathways. Results: The aged mice displayed increased susceptibility to fibrosis and decreased IL-10 expression. The 13-month-old IL-10KO mice exhibited significant exacerbation of cell senescence compared to their contemporary WT mice, and even more severe epithelial-mesenchymal transition (EMT) than that of 18 month WT mice. These IL-10 deficient mice showed heightened inflammatory responses and accelerated PF progression. Intratracheal administration of rIL-10 reduced lung CD45 + cell infiltration by 15%, including a 6% reduction in granulocytes and a 10% reduction in macrophages, and increased the proportion of AT2 cells by approximately 8%. Additionally, rIL-10 significantly decreased α-SMA and collagen deposition, and reduced the expression of senescence proteins p16 and p21 by 50% in these mice. In vitro analysis revealed that conditioned media from IL-10 deficient mice promoted SASP secretion and upregulated senescence genes in naïve lung fibroblasts, which was mitigated by rIL-10 treatment. Mechanistically, rIL-10 inhibited TGF-β-Smad2/3 and PTEN/PI3K/AKT/ERK pathways, thereby suppressing senescence and fibrosis-related proteins. Conclusions: IL-10 deficiency in aged mice leads to accelerated cell senescence and exacerbated fibrosis, with IL-10KO-PLFs displaying increased SASP secretion. Recombinant IL-10 treatment effectively mitigates these effects, suggesting its potential as a therapeutic target for PF. [ABSTRACT FROM AUTHOR]

Tumour cell senescence can be induced by various factors, including DNA damage, inflammatory signals, genetic toxins, ionising radiation and nutrient metabolism. The senescence‐associated secretory phenotype (SASP), secreted by senescent tumour cells, possesses the capacity to modulate various immune cells, including macrophages, T cells, natural killer cells and myeloid‐derived suppressor cells, as well as vascular endothelial cells and fibroblasts within the tumour microenvironment (TME), and this modulation can result in either the promotion or suppression of tumorigenesis and progression. Exploring the impact of SASP on the TME could identify potential therapeutic targets, yet limited studies have dissected its functions. In this review, we delve into the causes and mechanisms of tumour cell senescence. We then concentrate on the influence of SASP on the tumour immune microenvironment, angiogenesis, extracellular matrix and the reprogramming of cancer stem cells, along with their associated tumour outcomes. Last, we present a comprehensive overview of the diverse array of senotherapeutics, highlighting their prospective advantages and challenge for the treatment of cancer patients. Key points: Senescence‐associated secretory phenotype (SASP) secretion from senescent tumour cells significantly impacts cancer progression and biology.SASP is involved in regulating the remodelling of the tumour microenvironment, including immune microenvironment, vascular, extracellular matrix and cancer stem cells.Senotherapeutics, such as senolytic, senomorphic, nanotherapy and senolytic vaccines, hold promise for enhancing cancer treatment efficacy. [ABSTRACT FROM AUTHOR]

Simple Summary: The skin is the outermost barrier of the human body and consists of different layers and cell types. Several environmental and genetic factors can induce skin aging and age-related diseases. One of the main problems in skin aging is that senescent cells are accumulated and secrete factors, which can induce senescence in other tissues. Many researchers are trying to identify treatment modalities (known as senotherapies) to eliminate the senescent cells and reverse the aging process for chronic age-related diseases. The aim of this study is to address the mechanisms that induce senescence and the molecules with potential HAFi effects that are currently investigated for skin aging. Further studies should be conducted to elucidate all the effects of current senotherapies on the skin and other organs. Current data suggest that ongoing research projects in the field may lead to the discovery of new effective anti-senescence strategies in the skin. The skin is the layer of tissue that covers the largest part of the body in vertebrates, and its main function is to act as a protective barrier against external environmental factors, such as microorganisms, ultraviolet light and mechanical damage. Due to its important function, investigating the factors that lead to skin aging and age-related diseases, as well as understanding the biology of this process, is of high importance. Indeed, it has been reported that several external and internal stressors contribute to skin aging, similar to the aging of other tissues. Moreover, during aging, senescent cells accumulate in the skin and express senescence-associated factors, which act in a paracrine manner on neighboring healthy cells and tissues. In this review, we will present the factors that lead to skin aging and cellular senescence, as well as ways to study senescence in vitro and in vivo. We will further discuss the adverse effects of the accumulation of chronic senescent cells and therapeutic agents and tools to selectively target and eliminate them. [ABSTRACT FROM AUTHOR]

Objective(s): To study the anti-aging effect of (-)-α-bisabolol ((-)-α-bis) on the skin and preliminarily clarify its mechanism. Materials and Methods: Human skin fibroblasts (HSF) were induced senescence by D-Galactose. Senescence β-galactosidase staining was utilized to evaluate the senescence of HSF. TNF-α, IL6, IL-8, IL-1β, CCL-2, CCL-5, and MMP-9 in senescence-as-sociated secretory phenotype (SASP) were detected by RT-qPCR. Meanwhile, aged BALB/c mice were applied topically with 0.5% and 2%(-)-α-bis gel for 30 days continuously to evaluate anti-aging parameters on the skin such as surface measurement, the Trans Epidermal Water Loss (TEWL), and skin barrier index of dorsal skin. Then, HE staining, Masson staining, and IHC were applied to measure epidermal thickness, collagen fiber content in the dermis, and content of dermal collagen I, respectively. Last, SOD, MDA, and HYP contents of the back skin tissue of mice were also detected. Results: (-)-α-Bis reduced the expression of senescence-associated β-galactosidase (SA-β-gal) and expression levels of SASP in HSF cells stimulated by D-Gal (P<0.05). Mice aged 9 months were applied locally with (-)-α-bis gel to improve skin aging, the TEWL and skin barrier index of dorsal skin, and ameliorate the epidermal thickness and contents of dermal collagen fibers and collagen I (P<0.05). Furthermore, (-)-α-bis up-regulated the mRNA expression levels of elastin and collagen III effectively (P<0.05). Conclusion: (-)-α-Bis can delay the senescence of HSF cells by reducing the expression of SA-β-gal and SASP factors in vitro. Improved skin barrier function as well as SASP is responsible for the delay of skin aging in vivo. [ABSTRACT FROM AUTHOR]

Cellular senescence, one of the hallmarks of cancer, is characterized by cell cycle arrest and the loss of most normal cellular functions while acquiring a hypersecretory, proinflammatory phenotype. The function of senescent cells in cancer cells varies depending on the cellular conditions. Before the occurrence of cancer, senescent cells act as a barrier to prevent its development. But once cancer has occurred, senescent cells play a procancer role. However, few of the current studies have adequately explained the diversity of cellular senescence across cancers. Herein, we concluded the latest intrinsic mechanisms of cellular senescence in detail and emphasized the senescence‐associated secretory phenotype as a key contributor to heterogeneity of senescent cells in tumor. We also discussed five kinds of inducers of cellular senescence and the advancement of senolytics in cancer, which are drugs that tend to clear senescent cells. Finally, we summarized the various effects of senescent cells in different cancers and manifested that their functions may be diametrically opposed under different circumstances. In short, this paper contributes to the understanding of the diversity of cellular senescence in cancers and provides novel insight for tumor therapy. [ABSTRACT FROM AUTHOR]

Cellular aging is considered as one of the main factors implicated in female infertility. We evaluated the expression of senescence-associated secretory phenotype (SASP) markers and additional molecular factors in an in vitro model of cellular aging. We induced genotoxic stress (UVB/UVA ray irradiation) in primary human endometrial cells obtained from female subjects of young reproductive age (<35 years of age). We assessed the expression levels of IL-6, IL-8, IL-1α, MMP3, SIRT-1, SIRT-6, TERF-1, and CALR at the mRNA level by RT-qPCR and at the protein level by immunofluorescence and confocal microscopy in primary human endometrial cells upon induction of genotoxic stress and compared them to untreated cells. Statistically significant differences were found for the expression of SIRT-1, SIRT-6, and TERF, which were found to be decreased upon induction of cell senescence through genotoxic stress, while IL-6, IL-8, IL-1α, MMP3, and p16 were found to be increased in senescent cells. We propose that these molecules, in addition to SAS-linked factors, could represent novel markers, and eventually potential therapeutic targets, for the aging-associated dysfunction of the female reproductive system. [ABSTRACT FROM AUTHOR]

The aging of the world population is closely associated with an increased prevalence of musculoskeletal disorders, such as osteoporosis, sarcopenia, and osteoarthritis, due to common genetic, endocrine, and mechanical risk factors. These conditions are characterized by degeneration of bone, muscle, and cartilage tissue, resulting in an increased risk of fractures and reduced mobility. Importantly, a crucial role in the pathophysiology of these diseases has been proposed for cellular senescence, a state of irreversible cell cycle arrest induced by factors such as DNA damage, telomere shortening, and mitochondrial dysfunction. In addition, senescent cells secrete pro-inflammatory molecules, called senescence-associated secretory phenotype (SASP), which can alter tissue homeostasis and promote disease progression. Undoubtedly, targeting senescent cells and their secretory profiles could promote the development of integrated strategies, including regular exercise and a balanced diet or the use of senolytics and senomorphs, to improve the quality of life of the aging population. Therefore, our review aimed to highlight the role of cellular senescence in age-related musculoskeletal diseases, summarizing the main underlying mechanisms and potential anti-senescence strategies for the treatment of osteoporosis, sarcopenia, and osteoarthritis. [ABSTRACT FROM AUTHOR]

Breast and lung cancers are the leading causes of mortality and most frequently diagnosed cancers in women and men, respectively, worldwide. Although the antitumor activity of chalcones has been extensively studied, the molecular mechanisms of isoliquiritigenin analog 2', 4', 4-trihydroxychalcone (metochalcone; TEC) against carcinomas remain less well understood. In this study, we found that TEC inhibited cell proliferation of breast cancer BT549 cells and lung cancer A549 cells in a concentration-dependent manner. TEC induced cell cycle arrest in the S-phase, cell migration inhibition in vitro, and reduced tumor growth in vivo. Moreover, transcriptomic analysis revealed that TEC modulated the activity of the JAK2/STAT3 and P53 pathways. TEC triggered the senescence-associated secretory phenotype (SASP) by repressing the JAK2/STAT3 axis. The mechanism of metochalcone against breast cancer depended on the induction of SASP via deactivation of the JAK2/STAT3 pathway, highlighting the potential of chalcone in senescence-inducing therapy against carcinomas. [ABSTRACT FROM AUTHOR]

Abstract 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.

Background/Objective: Active 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. Methods: Bone 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. Results: ABT263 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. Conclusion: ABT263 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 article: This 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.

Abstract Background Pulmonary fibrosis (PF) is an aging-related progressive lung disorder. The aged lung undergoes functional and structural changes termed immunosenescence and inflammaging, which facilitate the occurrence of fibrosis. Interleukin-10 (IL-10) is a potent anti-inflammatory and immunoregulatory cytokine, yet it remains unclear how IL-10 deficiency-induced immunosenescence participates in the development of PF. Methods Firstly we evaluated the susceptibility to fibrosis and IL-10 expression in aged mice. Then 13-month-old wild-type (WT) and IL-10 knockout (KO) mice were subjected to bleomycin(BLM) and analyzed senescence-related markers by PCR, western blot and immunohistochemistry staining of p16, p21, p53, as well as DHE and SA-β-gal staining. We further compared 18-month-old WT mice with 13-month-old IL-10KO mice to assess aging-associated cell senescence and inflamation infiltration in both lung and BALF. Moreover, proliferation and apoptosis of alveolar type 2 cells(AT2) were evaluated by FCM, immunofluorescence, TUNEL staining, and TEM analysis. Recombinant IL-10 (rIL-10) was also administered intratracheally to evaluate its therapeutic potential and related mechanism. For the in vitro experiments, 10-week-old naïve pramily lung fibroblasts(PLFs) were treated with the culture medium of 13-month PLFs derived from WT, IL-10KO, or IL-10KO + rIL-10 respectively, and examined the secretion of senescence-associated secretory phenotype (SASP) factors and related pathways. Results The aged mice displayed increased susceptibility to fibrosis and decreased IL-10 expression. The 13-month-old IL-10KO mice exhibited significant exacerbation of cell senescence compared to their contemporary WT mice, and even more severe epithelial-mesenchymal transition (EMT) than that of 18 month WT mice. These IL-10 deficient mice showed heightened inflammatory responses and accelerated PF progression. Intratracheal administration of rIL-10 reduced lung CD45 + cell infiltration by 15%, including a 6% reduction in granulocytes and a 10% reduction in macrophages, and increased the proportion of AT2 cells by approximately 8%. Additionally, rIL-10 significantly decreased α-SMA and collagen deposition, and reduced the expression of senescence proteins p16 and p21 by 50% in these mice. In vitro analysis revealed that conditioned media from IL-10 deficient mice promoted SASP secretion and upregulated senescence genes in naïve lung fibroblasts, which was mitigated by rIL-10 treatment. Mechanistically, rIL-10 inhibited TGF-β-Smad2/3 and PTEN/PI3K/AKT/ERK pathways, thereby suppressing senescence and fibrosis-related proteins. Conclusions IL-10 deficiency in aged mice leads to accelerated cell senescence and exacerbated fibrosis, with IL-10KO-PLFs displaying increased SASP secretion. Recombinant IL-10 treatment effectively mitigates these effects, suggesting its potential as a therapeutic target for PF. Graphical Abstract

Objectives: To achieve a more beautiful and younger appearance, reducing wrinkles is a key concern. The process of wrinkle formation is complex and the development of truly effective cosmetic ingredients to reduce wrinkles remains a challenge. Recent studies have revealed a close relationship between wrinkles and skin thinning, suggesting that preventing skin thinning could also prevent wrinkle formation. In this study, we examined the role of extracellular adenosine triphosphate (eATP) in the progression of thinning, as eATP reportedly increases skin ageing factors, such as senescence‐associated secreted phenotype (SASP) factors in epidermal cells. We determined the effects of Mentha piperita leaf extract on suppressing eATP to reduce thinning and wrinkles. Methods: Adenosine triphosphate (ATP) levels were measured in normal human epidermal keratinocytes (NHEK) in the presence of M. piperita leaf extract. Dryness, high pH, and UVB radiation were used as extrinsic ageing factors. Intrinsic skin ageing was evaluated by comparing cells from adults (AD‐NHEK) and newborns (NB‐NHEK). A placebo‐controlled in vivo study was carried out with a formulation containing 1% M. piperita leaf extract. Results: The eATP levels were significantly higher in AD‐NHEK compared with that in NB‐NHEK cells. M. piperita leaf extract significantly decreased eATP levels in adult cells. Extrinsic ageing factors increased eATP levels in NHEK, whereas M. piperita leaf extract significantly suppressed eATP under all conditions. The active components of M. piperita leaf extract, luteolin glucuronide and rosmarinic acid, also decreased eATP. Moreover, compared with placebo lotion, M. piperita leaf extract‐formulated lotion markedly increased dermal thickness and reduced wrinkles associated with crow's feet and the neck area. Conclusion: We demonstrated for the first time that M. piperita leaf extract containing rosmarinic acid and luteolin‐7‐O‐glucuronide has the potential to reduce eATP release from epidermal keratinocytes. An increase in eATP was observed not only during inflammation but also during natural ageing. Furthermore, the in vivo experiment revealing that 1% M. piperita leaf extract‐containing lotion improved dermal thinning and wrinkles across multiple areas is attributed to the amelioration of dermal thinning. Thus, our data suggest the possibility of a novel cosmetic approach for reducing skin ageing by reducing eATP‐mediated dermal thinning. [ABSTRACT FROM AUTHOR]

Aging leads to a gradual decline in kidney function, making the kidneys increasingly vulnerable to various diseases. Oxidative stress, together with cellular senescence, has been established as paramount in promoting the aging process of the kidney. Oxidative stress, defined as an imbalance between ROS formation and antioxidant defense mechanisms, has been implicated in the kidney's cellular injury, inflammation, and premature senescence. Concurrently, the accumulation of SCs in the kidney also exacerbates oxidative stress via the secretion of pro-inflammatory and tissue-damaging factors as the senescence-associated secretory phenotype (SASP). Recently, SIRT1, a nicotinamide adenine dinucleotide (NAD)-dependent deacetylase, has been pivotal in combating oxidative stress and cellular senescence in the aging kidney. SIRT1 acts as a potential antioxidant molecule through myriad pathways that influence diverse transcription factors and enzymes essential in maintaining redox homeostasis. SIRT1 promotes longevity and renal health by modulating the acetylation of cell cycle and senescence pathways. This review covers the complex relationship between oxidative stress and cellular senescence in the aging kidney, emphasizing the protective role of SIRT1.

Abstract Cellular senescence (CS), a permanent and irreversible arrest of the cell cycle and proliferation leading to the degeneration of cellular structure and function, has been implicated in various key physiological and pathological processes, particularly in cancer. Initially, CS was recognized as a barrier to tumorigenesis, serving as an intrinsic defense mechanism to protect cells from malignant transformation. However, increasing evidence suggests that senescent cells can promote tumor progression to overt malignancy, primarily through a set of factors known as senescence-associated secretory phenotypes (SASPs), including chemokines, growth factors, cytokines, and stromal metalloproteinases. These factors significantly reshape the tumor microenvironment (TME), enabling tumors to evade immune destruction. Interestingly, some studies have also suggested that SASPs may impede tumor development by enhancing immunosurveillance. These opposing roles highlight the complexity and heterogeneity of CS and SASPs in diverse cancers. Consequently, there has been growing interest in pharmacological interventions targeting CS or SASPs in cancer therapy, such as senolytics and senomorphics, to either promote the clearance of senescent cells or mitigate the harmful effects of SASPs. In this review, we will interpret the concept of CS, delve into the role of SASPs in reshaping the TME, and summarize recent advances in anti-tumor strategies targeting CS or SASPs.

Tumor-associated macrophages (TAMs) are an important and most represented population of immune cells in the tumor microenvironment. To a great extent, TAMs can determine the direction of the antitumor immune response; they can either additionally stimulate it or on the contrary contribute to the formation of immunosuppressive microenvironment. At the same time, under the influence of tumor cells and antitumor therapy, many cells in the tumor microenvironment (TME) can develop a state of senescence. Over the last decade, the topic of senescence and the search for therapies aimed at removing senescent cells has gained popularity. In the search for new therapeutic strategies to treat cancer, senescent cells of the immune system in the tumor microenvironment have received special attention since the presence of senescent TAMs in tumors is associated with poor prognosis and poor response to therapy. Given the relevance of studying the role of senescent immune cells in TME (in particular tumor-associated macrophages), we performed a comparative analysis of experimental protocols to obtain tumor-associated macrophages in vitro to determine the most relevant approach. We tested two protocols for obtaining macrophages from mouse bone marrow: (1) by adding conditioned medium from the L929 mouse sarcoma cell line (LCCM) (LCCM-BMDM); and (2) by adding recombinant mouse M-CSF (M-CSF-BMDM). We showed that LCCM-BMDMs, compared to M-CSFBMDMs, have increased expression of the arginase enzyme (Arg1), which can inhibit the activity of anti-tumor cytotoxic lymphocytes by depleting arginine in the tumor microenvironment. LCCM-BMDMs also exhibited increased secretion of factors characteristic of the senescence-associated secretory phenotype (SASP): IL-6 and TNF. Both Arg1 and IL-6 and TNF are markers characteristic of senescence-associated macrophages. Thus, the use of LCCM to obtain primary macrophage culture limits further steps in creating a model of tumor-associated macrophages that reflects the specific characteristics of the macrophage phenotypic response for different tumor types aAnd also limits studies of senescence formation in tumor-associated macrophages in models of carcinogenesis other than sarcoma. We believe that differentiation of macrophages in the presence of M-CSF appears to be a more preferable protocol to study TAMs and senescent TAMs to test new therapeutic strategies.

Abstract Background We previously identified Il17RB, a member of the IL17 superfamily, as a candidate marker gene for endometrial aging. While IL17RB has been linked to inflammation and malignancies in several organ systems, its function in the endometrium has not been investigated and is thus poorly understood. In the present study, we performed a functional analysis of this receptor with the aim of determining the effects of its age-associated overexpression on the uterine environment. Methods We analyzed IL17RB-related signaling pathways and downstream gene expression in an immortalized human endometrial glandular epithelial cell line (“hEM”) forced to express the receptor via lentiviral transduction (“IL17RB-hEM”). We also prepared endometrial organoids from human endometrial tissue sourced from hysterectomy patients (“patient-derived EOs”) and exposed them to cytokines that are upregulated by IL17RB expression to investigate changes in organoid-forming capacity and senescence markers. We analyzed RNA-seq data (GEO accession number GSE132886) from our previous study to identify the signaling pathways associated with altered IL17RB expression. We also analyzed the effects of the JNK pathway on organoid-forming capacity. Results Stimulation with interleukin 17B enhanced the NF-κB pathway in IL17RB-hEM, resulting in significantly elevated expression of the genes encoding the senescence associated secretory phenotype (SASP) factors IL6, IL8, and IL1β. Of these cytokines, IL1β inhibited endometrial organoid growth. Bioinformatics analysis showed that the JNK signaling pathway was associated with age-related variation in IL17RB expression. When IL17RB-positive cells were cultured in the presence of IL17B, their organoid-forming capacity was slightly but non-significantly lower than in unexposed IL17RB-positive cells, but when IL17B was paired with a JNK inhibitor (SP600125), it was restored to control levels. Further, IL1β exposure significantly reduced organoid-forming capacity and increased p21 expression in endometrial organoids relative to non-exposure (control), but when IL1β was paired with SP600125, both indicators were restored to levels comparable to the control condition. Conclusions We have revealed an association between IL17RB, whose expression increases in the endometrial glandular epithelium with advancing age, and cellular senescence. Using human endometrial organoids as in vitro model, we found that IL1β inhibits cell proliferation and leads to endometrial senescence via the JNK pathway.

Abstract Background The progression of Parkinson’s disease (PD) is related to ageing. The accumulation of nuclear alpha-synuclein (α-syn) may accelerate the occurrence of neurodegenerative diseases, but its role in PD remains poorly understood. Methods In the present study, α-syn expression was specifically targeted to the nucleus by constructing an adeno-associated virus (AAV) vector in which a nuclear localization sequence (NLS) was added to the α-syn coding sequence. Virus-mediated gene transfer, behavioural tests, RNA-Seq, immunohistochemistry, western blotting, and quantitative real-time PCR were then performed. Results In vivo experiments using a mouse model showed that nuclear α-syn increased the severity of the PD-like phenotype, including the loss of dopaminergic neurons concomitant with motor impairment and the formation of α-syn inclusions. These nuclear inclusions contained α-syn species of high molecular weights and induced strong transcriptional dysregulation, especially induced high expression of p21 and senescence-associated secretory phenotype (SASP)-related genes. In addition, the transcriptional alterations induced by nuclear α-syn were associated with gliosis, inflammation, oxidative and DNA damage, and lysosomal dysfunction, and they eventually accelerated neuronal loss and neurodegeneration. Conclusions Our results suggest that nuclear α-syn plays a crucial role in PD pathogenesis.

Cellular senescence (CS), a permanent and irreversible arrest of the cell cycle and proliferation leading to the degeneration of cellular structure and function, has been implicated in various key physiological and pathological processes, particularly in cancer. Initially, CS was recognized as a barrier to tumorigenesis, serving as an intrinsic defense mechanism to protect cells from malignant transformation. However, increasing evidence suggests that senescent cells can promote tumor progression to overt malignancy, primarily through a set of factors known as senescence-associated secretory phenotypes (SASPs), including chemokines, growth factors, cytokines, and stromal metalloproteinases. These factors significantly reshape the tumor microenvironment (TME), enabling tumors to evade immune destruction. Interestingly, some studies have also suggested that SASPs may impede tumor development by enhancing immunosurveillance. These opposing roles highlight the complexity and heterogeneity of CS and SASPs in diverse cancers. Consequently, there has been growing interest in pharmacological interventions targeting CS or SASPs in cancer therapy, such as senolytics and senomorphics, to either promote the clearance of senescent cells or mitigate the harmful effects of SASPs. In this review, we will interpret the concept of CS, delve into the role of SASPs in reshaping the TME, and summarize recent advances in anti-tumor strategies targeting CS or SASPs. [ABSTRACT FROM AUTHOR]

Drug delivery systems (DDSs) enable the controlled release of drugs in the body. DDSs have attracted increasing attention for the treatment of various disorders, including cancer, inflammatory diseases, and age-related diseases. With recent advancements in our understanding of the molecular mechanisms of aging, new target molecules and drug delivery carriers for age-related diseases have been reported. In this review, we will summarize the recent research on DDSs for age-related diseases and identify DDS strategies in the treatment of age-related diseases. [ABSTRACT FROM AUTHOR]

Currently, there is a growing focus on aging and age-related diseases. The processes of aging are based on cell senescence, which results in changes in intercellular communications and pathological alterations in tissues. In the present study, we investigate the influence of senescent mesenchymal stem cells (MSCs) on endothelial cells (ECs). In order to induce senescence in MSCs, we employed a method of stress-induced senescence utilizing mitomycin C (MmC). Subsequent experiments involved the interaction of ECs with MSCs in a coculture or the treatment of ECs with the secretome of senescent MSCs. After 48 h, we assessed the EC state. Our findings revealed that direct interaction led to a decrease in EC proliferation and migratory activity of the coculture. Furthermore, there was an increase in the activity of the lysosomal compartment, as well as an upregulation of the genes P21, IL6, IL8, ITGA1, and ITGB1. Treatment of ECs with the "senescent" secretome resulted in less pronounced effects, although a decrease in proliferation and an increase in ICAM-1 expression were observed. The maintenance of high levels of typical "senescent" cytokines and growth factors after 48 h suggests that the addition of the "senescent" secretome may have a prolonged effect on the cells. It is noteworthy that in samples treated with the "senescent" secretome, the level of PDGF-AA was higher, which may explain some of the pro-regenerative effects of senescent cells. Therefore, the detected changes may underlie both the negative and positive effects of senescence. The findings provide insight into the effects of cell senescence in vitro, where many of the organism's regulatory mechanisms are absent. [ABSTRACT FROM AUTHOR]

Cellular senescence contributes to inflammatory kidney disease via the secretion of inflammatory and profibrotic factors. Protease‐activating receptor 2 (PAR2) is a key regulator of inflammation in kidney diseases. However, the relationship between PAR2 and cellular senescence in kidney disease has not yet been described. In this study, we found that PAR2‐mediated metabolic changes in renal tubular epithelial cells induced cellular senescence and increased inflammatory responses. Using an aging and renal injury model, PAR2 expression was shown to be associated with cellular senescence. Under in vitro conditions in NRK52E cells, PAR2 activation induces tubular epithelial cell senescence and senescent cells showed defective fatty acid oxidation (FAO). Cpt1α inhibition showed similar senescent phenotype in the cells, implicating the important role of defective FAO in senescence. Finally, we subjected mice lacking PAR2 to aging and renal injury. PAR2‐deficient kidneys are protected from adenine‐ and cisplatin‐induced renal fibrosis and injury, respectively, by reducing senescence and inflammation. Moreover, kidneys lacking PAR2 exhibited reduced numbers of senescent cells and inflammation during aging. These findings offer fresh insights into the mechanisms underlying renal senescence and indicate that targeting PAR2 or FAO may be a promising therapeutic approach for managing kidney injury. [ABSTRACT FROM AUTHOR]

Senescent cells accumulate in various organs with ageing, and its accumulation induces chronic inflammation and age-related physiological dysfunctions. Several remodelling of intracellular environments have been identified in senescent cells, including enlargement of cell/nuclear size and intracellular acidification. Although these alterations of intracellular environments were reported to be involved in the unique characteristics of senescent cells, the contribution of intracellular acidification to senescence-associated cellular phenotypes is poorly understood. Here, we identified that the upregulation of TXNIP and its paralog ARRDC4 as a hallmark of intracellular acidification in addition to KGA-type GLS1. These genes were also upregulated in response to senescence-associated intracellular acidification. Neutralization of the intracellular acidic environment ameliorated not only senescence-related upregulation of TXNIP , ARRDC4 and KGA but also inflammation-related genes, possibly through suppression of PDK-dependent anaerobic glycolysis. Furthermore, we found that expression of the intracellular acidification-induced genes, TXNIP and ARRDC4 , correlated with inflammatory gene expression in heterogeneous senescent cell population in vitro and even in vivo , implying that the contribution of intracellular pH to senescence-associated cellular features, such as SASP. [ABSTRACT FROM AUTHOR]

Therapy-induced senescence (TIS) represents a major cellular response to anticancer treatments. Both malignant and non-malignant cells in the tumor microenvironment undergo TIS and may be harmful for cancer patients since TIS cells develop a senescence-associated secretory phenotype (SASP) that can sustain tumor growth. The SASP also modulates anti-tumor immunity, although the immune populations involved and the final results appear to be context-dependent. In addition, senescent cancer cells are able to evade senescence growth arrest and to resume proliferation, likely contributing to relapse. So, research data suggest that TIS induction negatively affects therapy outcomes in cancer patients. In line with this, new interventions aimed at the removal of senescent cells or the reprogramming of their SASP, called senotherapy, have become attractive therapeutic options. To date, the lack of reliable, cost-effective, and easy-to-use TIS biomarkers hinders the application of recent anti-senescence therapeutic approaches in the clinic. Hence, the identification of biomarkers for the detection of TIS tumor cells and TIS non-neoplastic cells is a high priority in cancer research. In this review article, we describe the current knowledge about TIS, outline critical gaps in our knowledge, and address recent advances and novel approaches for the discovery of TIS biomarkers. [ABSTRACT FROM AUTHOR]

Background: Senescence is a cellular aging-related process triggered by different stresses and characterized by the secretion of various inflammatory factors referred to as senescence-associated secretory phenotype (SASP), some of which are produced by the NLRP3 inflammasome. Here, we present evidence that the NLRP1 inflammasome is a DNA damage sensor and a key mediator of senescence. Methods: Senescence was induced in fibroblasts in vitro and in mice. Cellular senescence was assessed by Western blot analysis of several proteins, including p16, p21, p53, and SASP factors, released in the culture media or serum. Inflammasome components, including NLRP1, NLRP3 and GSDMD were knocked out or silenced using siRNAs. Results: In vitro and in vivo results suggest that the NLRP1 inflammasome promotes senescence by regulating the expression of p16, p21, p53, and SASP factors in a Gasdermin D (GSDMD)-dependent manner. Mechanistically, the NLRP1 inflammasome is activated in response to genomic damage detected by the cytosolic DNA sensor cGMP-AMP (cGAMP) synthase (cGAS). Conclusion: Our findings show that NLRP1 is a cGAS-dependent DNA damage sensor during senescence and a mediator of SASP release through GSDMD. This study advances the knowledge on the biology of the NLRP1 inflammasome and highlights this pathway as a potential pharmcological target to modulate senescence. [ABSTRACT FROM AUTHOR]

The word "secretome" was first used to describe the proteins that cells secrete under different circumstances; however, recent studies have proven the existence of other molecules such as RNA and chemical compounds in the secretome. The study of secretome has significance for the diagnosis and treatment of disease as it provides insight into cellular functions, including immune responses, development, and homeostasis. By halting cell division, cellular senescence plays a role in both cancer defense and aging by secreting substances known as senescence-associated secretory phenotypes (SASP). A variety of techniques could be used to analyze the secretome: protein-based approaches like mass spectrometry and protein microarrays, nucleic acid-based methods like RNA sequencing, microarrays, and in silico prediction. Each method offers unique advantages and limitations in characterizing secreted molecules. Top-down and bottom-up strategies for thorough secretome analysis are became possible by mass spectrometry. Understanding cellular function, disease causes, and proper treatment targets is aided by these methodologies. Their approaches, benefits, and drawbacks will all be discussed in this review. [ABSTRACT FROM AUTHOR]

The influence of chronic diseases on various facets of macrophage cellular senescence is poorly understood. This study evaluated the impact of chronic hyperglycemia on the induction of cellular senescence and subsequent immunosurveillance functions in RAW264.7 macrophages. Macrophages were cultured under normal glucose (NG; 5 mM), high glucose (HG; 20 mM), and very high glucose (VHG; 40 mM) conditions and assessed for markers of cellular senescence. Hyperglycemia induced strong upregulation of SA-β-gal activity, and loss of PCNA and Lamin B1 gene expression while markers of cell cycle arrest generally decreased. Non-significant changes in SASP-related proteins were observed while ROS levels slightly decreased and mitochondrial membrane potential increased. Protein concentration on the exosome membrane surface and their stability appeared to increase under hyperglycemic conditions. However, when macrophages were exposed to the secretory media (SM) of senescent preadipocytes, a dramatic increase in the levels of all inflammatory proteins was recorded especially in the VHG group that was also accompanied by upregulation of NF-κB and NLRP3 gene expression. SM treatment to hyperglycemic macrophages activated the TLR-2/Myd88 pathway but decreased the expression of scavenger receptors RAGE, CD36, and Olr-1 while CD44 and CXCL16 expression increased. On exposure to LPS, a strong upregulation in NO, ROS, and inflammatory cytokines was observed. Together, these results suggest that primary markers of cellular senescence are aberrantly expressed under chronic hyperglycemic conditions in macrophages with no significant SASP activation. Nonetheless, hyperglycemia strongly deregulates macrophage functions leading to impaired immunosurveillance of senescent cells and aggravation of inflamm-aging. This work provides novel insights into how hyperglycemia-induced dysfunctions can impact the potency of macrophages to manage senescent cell burden in aging tissues. [ABSTRACT FROM AUTHOR]

Background: We previously identified Il17RB, a member of the IL17 superfamily, as a candidate marker gene for endometrial aging. While IL17RB has been linked to inflammation and malignancies in several organ systems, its function in the endometrium has not been investigated and is thus poorly understood. In the present study, we performed a functional analysis of this receptor with the aim of determining the effects of its age-associated overexpression on the uterine environment. Methods: We analyzed IL17RB-related signaling pathways and downstream gene expression in an immortalized human endometrial glandular epithelial cell line ("hEM") forced to express the receptor via lentiviral transduction ("IL17RB-hEM"). We also prepared endometrial organoids from human endometrial tissue sourced from hysterectomy patients ("patient-derived EOs") and exposed them to cytokines that are upregulated by IL17RB expression to investigate changes in organoid-forming capacity and senescence markers. We analyzed RNA-seq data (GEO accession number GSE132886) from our previous study to identify the signaling pathways associated with altered IL17RB expression. We also analyzed the effects of the JNK pathway on organoid-forming capacity. Results: Stimulation with interleukin 17B enhanced the NF-κB pathway in IL17RB-hEM, resulting in significantly elevated expression of the genes encoding the senescence associated secretory phenotype (SASP) factors IL6, IL8, and IL1β. Of these cytokines, IL1β inhibited endometrial organoid growth. Bioinformatics analysis showed that the JNK signaling pathway was associated with age-related variation in IL17RB expression. When IL17RB-positive cells were cultured in the presence of IL17B, their organoid-forming capacity was slightly but non-significantly lower than in unexposed IL17RB-positive cells, but when IL17B was paired with a JNK inhibitor (SP600125), it was restored to control levels. Further, IL1β exposure significantly reduced organoid-forming capacity and increased p21 expression in endometrial organoids relative to non-exposure (control), but when IL1β was paired with SP600125, both indicators were restored to levels comparable to the control condition. Conclusions: We have revealed an association between IL17RB, whose expression increases in the endometrial glandular epithelium with advancing age, and cellular senescence. Using human endometrial organoids as in vitro model, we found that IL1β inhibits cell proliferation and leads to endometrial senescence via the JNK pathway. [ABSTRACT FROM AUTHOR]

This narrative review explores the pathophysiology of obesity, cellular senescence, and exosome release. When exposed to excessive nutrients, adipocytes develop mitochondrial dysfunction and generate reactive oxygen species with DNA damage. This triggers adipocyte hypertrophy and hypoxia, inhibition of adiponectin secretion and adipogenesis, increased endoplasmic reticulum stress and maladaptive unfolded protein response, metaflammation, and polarization of macrophages. Such feed-forward cycles are not resolved by antioxidant systems, heat shock response pathways, or DNA repair mechanisms, resulting in transmissible cellular senescence via autocrine, paracrine, and endocrine signaling. Senescence can thus affect preadipocytes, mature adipocytes, tissue macrophages and lymphocytes, hepatocytes, vascular endothelium, pancreatic β cells, myocytes, hypothalamic nuclei, and renal podocytes. The senescence-associated secretory phenotype is closely related to visceral adipose tissue expansion and metaflammation; inhibition of SIRT-1, adiponectin, and autophagy; and increased release of exosomes, exosomal micro-RNAs, pro-inflammatory adipokines, and saturated free fatty acids. The resulting hypernefemia, insulin resistance, and diminished fatty acid β-oxidation lead to lipotoxicity and progressive obesity, metabolic syndrome, and physical and cognitive functional decline. Weight cycling is related to continuing immunosenescence and exposure to palmitate. Cellular senescence, exosome release, and the transmissible senescence-associated secretory phenotype contribute to obesity and metabolic syndrome. Targeted therapies have interrelated and synergistic effects on cellular senescence, obesity, and premature aging. [ABSTRACT FROM AUTHOR]

Introduction: The tumor microenvironment gained attraction over the last decades as stromal cells significantly impact on tumor development, progression and metastasis, and immune evasion as well as on cancer therapy resistance. We previously reported that lung-resident mesenchymal stem cells (MSCs) were mobilized and activated in non-small cell lung cancer (NSCLC) progression and could even mediate radiation resistance in co-cultured NSCLC cells. Methods: We investigated how MSCs were affected by NSCLC cells in combination with cancer (radiation) therapy in indirect co-cultures using tumor-conditioned medium and Transwells or direct three-dimensional NSCLC-MSC spheroid co-cultures in order to unravel the resistancemediating action of tumor-associated MSCs. Results: Although no obvious phenotypic and functional alterations in MSCs following NSCLC co-culture could be observed, MSC senescence was induced following co-applied radiotherapy (RT). Global gene expression profiling, in combination with gene set enrichment analysis upon treatment, was used to confirm the senescent phenotype of irradiated MSC and to reveal relevant senescence-associated secretory phenotype (SASP) factors that could meditate NSCLC RT resistance. We identified senescent tumor-associated MSC-derived serine proteinase inhibitor (serpin) E1/PAI1 as potential SASP factor mediating NSCLC progression and RT resistance. Discussion: Specified intra-tumor-stroma interactions and cell type-specific pro-tumorigenic functions could not only improve lung cancer classification but could even be used for a more precise profiling of individual patients, finally paving an additional way for the discovery of potential drug targets for NSCLC patients. [ABSTRACT FROM AUTHOR]

Background: The progression of Parkinson's disease (PD) is related to ageing. The accumulation of nuclear alpha-synuclein (α-syn) may accelerate the occurrence of neurodegenerative diseases, but its role in PD remains poorly understood. Methods: In the present study, α-syn expression was specifically targeted to the nucleus by constructing an adeno-associated virus (AAV) vector in which a nuclear localization sequence (NLS) was added to the α-syn coding sequence. Virus-mediated gene transfer, behavioural tests, RNA-Seq, immunohistochemistry, western blotting, and quantitative real-time PCR were then performed. Results: In vivo experiments using a mouse model showed that nuclear α-syn increased the severity of the PD-like phenotype, including the loss of dopaminergic neurons concomitant with motor impairment and the formation of α-syn inclusions. These nuclear inclusions contained α-syn species of high molecular weights and induced strong transcriptional dysregulation, especially induced high expression of p21 and senescence-associated secretory phenotype (SASP)-related genes. In addition, the transcriptional alterations induced by nuclear α-syn were associated with gliosis, inflammation, oxidative and DNA damage, and lysosomal dysfunction, and they eventually accelerated neuronal loss and neurodegeneration. Conclusions: Our results suggest that nuclear α-syn plays a crucial role in PD pathogenesis. [ABSTRACT FROM AUTHOR]

The problem of human exposure to ionizing radiation has attracted increasing attention in various scientific fields. Recently, a substantial amount of data has been collected on the age-related risks associated with radiation exposure, which has enabled researchers to uncover the relationship between ionizing radiation and cellular senescence. This has led to the search for cellular targets of radiation, with mitochondria being one of the identified targets. Ionizing radiation causes mitochondrial dysfunction and the emergence of a characteristic age-related phenotype in cells, including increased ROS production, SASP development, changes in the epigenetic profile, and genomic instability. Mitochondrial dysfunction is often underestimated as a crucial hallmark of cellular senescence, and its underlying mechanisms are extensive and complex. In particular, mitochondrial miRNAs (mitomiRs) that regulate mitochondrial gene expression, and consequently, the function and dynamics of the organelles themselves, are of particular interest. Considering that mitomiRs are highly sensitive to even minor disturbances arising from irradiation, resulting in significant changes in their expression, they may serve as promising biomarkers of radiation exposure. In this review, we examine the evidence supporting the key role of mitomiRs in radiation-induced cellular senescence and integrate the latest knowledge on the underlying molecular mechanisms of this interaction. [ABSTRACT FROM AUTHOR]

The role of the senescence‐associated secretory phenotype (SASP) in the development of age‐related diseases is significant, and its control promises to have a tremendous positive impact on health. A recent study has identified a new mechanism for SASP regulation, titled miMOMP. Failure to regulate SASP would dramatically increase the risk of various age‐related health problems. Nonetheless, we have not completely comprehended how to modulate SASP. In this commentary, we summarise the specific mechanisms by which miMOMP regulates SASP and outline possible future research directions. Moreover, potential risks and obstacles to the clinical translation of miMOMP are also presented. [ABSTRACT FROM AUTHOR]

Aim Ohmic heating (OH) (i.e. heating by electric field) more effectively kills bacterial spores than traditional wet heating, yet its mechanism remains poorly understood. This study investigates the accelerated spore inactivation mechanism using genetically modified spores. Methods and results We investigated the effects of OH and conventional heating (CH) on various genetically modified strains of Bacillus subtilis : isogenic PS533 (wild type_1), PS578 [lacking spores' α/β-type small acid-soluble proteins (SASP)], PS2318 (lacking recA , encoding a DNA repair protein), isogenic PS4461 (wild type_2), and PS4462 (having the 2Duf protein in spores, which increases spore wet heat resistance and decreases spore inner membrane fluidity). Removal of SASP brought the inactivation profiles of OH and CH closer, suggesting the interaction of these proteins with the field. However, the reemergence of a difference between CH and OH killing for SASP-deficient spores at the highest tested field strength suggested there is also interaction of the field with another spore core component. Additionally, RecA-deficient spores yielded results like those with the wild-type spores for CH, while the OH resistance of this mutant increased at the lower tested temperatures, implying that RecA or DNA are a possible additional target for the electric field. Addition of the 2Duf protein markedly increased spore resistance both to CH and OH, although some acceleration of killing was observed with OH at 50 V/cm. Conclusions In summary, both membrane fluidity and interaction of the spore core proteins with electric field are key factors in enhanced spore killing with electric field-heat combinations. [ABSTRACT FROM AUTHOR]

Biological aging results from an accumulation of damage in the face of reduced resilience. One major driver of aging is cell senescence, a state in which cells remain viable but lose their proliferative capacity, undergo metabolic alterations, and become resistant to apoptosis. This is accompanied by complex cellular changes that enable the development of a senescence-associated secretory phenotype (SASP). Mitochondria, organelles involved in energy provision and activities essential for regulating cell survival and death, are negatively impacted by aging. The age-associated decline in mitochondrial function is also accompanied by the development of chronic low-grade sterile inflammation. The latter shares some features and mediators with the SASP. Indeed, the unloading of damage-associated molecular patterns (DAMPs) at the extracellular level can trigger sterile inflammatory responses and mitochondria can contribute to the generation of DAMPs with pro-inflammatory properties. The extrusion of mitochondrial DNA (mtDNA) via mitochondrial outer membrane permeabilization under an apoptotic stress triggers senescence programs. Additional pathways can contribute to sterile inflammation. For instance, pyroptosis is a caspase-dependent inducer of systemic inflammation, which is also elicited by mtDNA release and contributes to aging. Herein, we overview the molecular mechanisms that may link mitochondrial dyshomeostasis, pyroptosis, sterile inflammation, and senescence and discuss how these contribute to aging and could be exploited as molecular targets for alleviating the cell damage burden and achieving healthy longevity. [ABSTRACT FROM AUTHOR]

Cellular senescence is a state of durable cell arrest that has been identified both in vitro and in vivo. It is associated with profound changes in gene expression and a specific secretory profile that includes pro‐inflammatory cytokines, growth factors and matrix‐remodelling enzymes, referred to as the senescence‐associated secretory phenotype (SASP). In cancer, senescence can have anti‐ or pro‐tumour effects. On one hand, it can inhibit tumour progression in a cell autonomous manner. On the other hand, senescence can also promote tumour initiation, progression, metastatic dissemination and resistance to therapy in a paracrine manner. Therefore, despite efforts to target senescence as a potential strategy to inhibit tumour growth, senescent cancer and microenvironmental cells can eventually lead to uncontrolled proliferation and aggressive tumour phenotypes. This can happen either through overcoming senescence growth arrest or through SASP‐mediated effects in adjacent tumour cells. This review will discuss how senescence affects the tumour microenvironment, including extracellular matrix remodelling, the immune system and the vascular compartment, to promote tumourigenesis, metastasis and resistance to DNA‐damaging therapies. It will also discuss current approaches used in the field to target senescence: senolytics, improving the immune clearance of senescent cells and targeting the SASP. [ABSTRACT FROM AUTHOR]

Senescent cells have a profound impact on the surrounding microenvironment through the secretion of numerous bioactive molecules and inflammatory factors. The induction of therapy-induced senescence by anticancer drugs is known, but how senescent tumor cells influence the tumor immune landscape, particularly neutrophil activity, is still unclear. In this study, we investigate the induction of cellular senescence in breast cancer cells and the subsequent immunomodulatory effects on neutrophils using the CDK4/6 inhibitor palbociclib, which is approved for the treatment of breast cancer and is under intense investigation for additional malignancies. Our research demonstrates that palbociclib induces a reversible form of senescence endowed with an inflammatory secretome capable of recruiting and activating neutrophils, in part through the action of interleukin-8 and acute-phase serum amyloid A1. The activation of neutrophils is accompanied by the release of neutrophil extracellular trap and the phagocytic removal of senescent tumor cells. These findings may be relevant for the success of cancer therapy as neutrophils, and neutrophil-driven inflammation can differently affect tumor progression. Our results reveal that neutrophils, as already demonstrated for macrophages and natural killer cells, can be recruited and engaged by senescent tumor cells to participate in their clearance. Understanding the interplay between senescent cells and neutrophils may lead to innovative strategies to cope with chronic or tumor-associated inflammation. [ABSTRACT FROM AUTHOR]

Aging negatively affects the appearance and texture of the skin owing to the accumulation of senescent fibroblasts within the dermis. Senescent cells undergo abnormal remodeling of collagen and the extracellular matrix through an inflammatory histolytic senescence-associated secretory phenotype (SASP). Therefore, suppression of SASP in senescent cells is essential for the development of effective skin anti-aging therapies. Ectonucleotide pyrophosphatase/phosphodiesterase family member 5 (ENPP5), an extracellular signaling molecule, has been implicated in vascular aging and apoptosis; however, its role in SASP remains unclear. Therefore, this study aimed to investigate the role of ENPP5 in SASP and skin aging using molecular techniques. We investigated the effects of siRNA-mediated ENPP5 knockdown, human recombinant ENPP5 (rENPP5) treatment, and lentiviral overexpression of ENPP5 on SASP and aging in human skin fibroblasts. Additionally, we investigated the effect of siRNA-mediated ENPP5 knockdown on the skin of C57BL/6 mice. We found that ENPP5 was significantly expressed in replication-aged and otherwise DNA-damaged human skin fibroblasts and that treatment with human rENPP5 and lentiviral overexpression of ENPP5 promoted SASP and senescence. By contrast, siRNA-mediated knockdown of ENPP5 suppressed SASP and the expression of skin aging-related factors. Additionally, ENPP5 knockdown in mouse skin ameliorated the age-related reduction of subcutaneous adipose tissue, the panniculus carnosus muscle layer, and thinning of collagen fibers. Conclusively, these findings suggest that age-related changes may be prevented through the regulation of ENPP5 expression to suppress SASP in aging cells, contributing to the development of anti-aging treatments for the skin. [ABSTRACT FROM AUTHOR]

Of the factors studied in individual ageing, the accumulation of senescent cells has been considered as an essential cause of organ degeneration to eventually initiate age-related diseases. Cellular senescence is attributed to the accumulation of damage for an inducement in the activation of cell cycle inhibitory pathways, resulting the cell permanently withdraw from the cell proliferation cycle. Further, senescent cells will activate the inflammatory factor secretion pathway to promote the development of various age-related diseases. Senolytics, a small molecule compound, can delay disease development and extend mammalian lifespan. The evidence from multiple trials shows that the targeted killing of senescent cells has a significant clinical application for the treatment of age-related diseases. In addition, senolytics are also significant for the development of ageing research in solid organ transplantation, which can fully develop the potential of elderly organs and reduce the age gap between demand and supply. We conclude that the main characteristics of cellular senescence, the anti-ageing drug senolytics in the treatment of chronic diseases and organ transplantation, and the latest clinical progress of related researches in order to provide a theoretical basis for the prevention and treatment of ageing and related diseases. [ABSTRACT FROM AUTHOR]

Aging is a universal physiological phenomenon, and chronic age-related diseases have become one of the leading causes of human mortality, accounting for nearly half of all deaths. Studies have shown that reducing the incidence of these diseases can not only extend lifespan but also promote healthy aging. In recent years, the potential role of non-histone high-mobility group proteins (HMGs) in the regulation of aging and lifespan has attracted widespread attention. HMGs play critical roles in cellular senescence and associated diseases through various pathways, encompassing multi-layered mechanisms involving protein interactions, molecular regulation, and chromatin dynamics. This review provides a comprehensive analysis of the interactions between HMG family proteins and senescence-associated secretory phenotype (SASP), chromatin structure, and histone modifications, offering a deeper exploration of the pivotal functions and impacts of HMGs in the aging process. Furthermore, we summarize recent findings on the contributions of HMG proteins to aging and age-related diseases. HMG proteins not only regulate senescence-associated inflammation through modulating the SASP but also influence genomic stability and cell fate decisions via interactions with chromatin and histones. Targeting HMG proteins holds great potential in delaying the progression of aging and its associated diseases. This review aims to provide a systematic overview of HMG proteins’ roles in aging and to lay a solid foundation for future anti-aging drug development and therapeutic strategies. With the advancing understanding of the mechanisms by which HMGs regulate aging, developing therapeutic interventions targeting HMGs may emerge as a promising approach to extending lifespan and enhancing healthspan.

BackgroundRecent studies have shown that the high salt diet (HSD) is linked to increased dermal pro-inflammatory status and reduced extracellular matrix (ECM) expression in inflamed skin of mice. Decreased ECM content is a known aging phenotype of the skin, and alterations in ECM composition and organization significantly contribute to skin aging. This study aimed to determine whether a high salt diet accelerates skin aging and to identify the time point at which this effect becomes apparent.MethodsWistar rats were randomly divided into normal diet and high salt diet groups and fed continuously for 8 weeks. Skin samples were collected at weeks 7 and week 8. Skin pathological sections were evaluated and levels of cell cycle inhibitors, senescence-associated secretory phenotype (SASP), oxidative stress and vascular regulatory factors (VRFs) were examined. Correlation analyses were performed to reveal the effect of a high salt diet as an extrinsic factor on skin aging and to analyse the correlation between a high salt diet and intrinsic aging and blood flow status.ResultsAt week 8, HSD rats exhibited thickened epidermis, thinned dermis, and atrophied hair follicles. The expression of cell cycle inhibitors and oxidative stress levels were significantly elevated in the skin of HSD rats at both week 7 and week 8. At week 7, some SASPs, including TGF-β and PAI-1, were elevated, but others (IL-1, IL-6, IL-8, NO) were not significantly changed. By week 8, inflammatory molecules (IL-1, IL-6, TGF-β), chemokines (IL-8), proteases (PAI-1), and non-protein molecules (NO) were significantly increased. Notably, despite elevated PAI-1 levels suggesting possible blood hypercoagulation, the ET-1/NO ratio was reduced in the HSD group at week 8.ConclusionThe data suggest that a high salt diet causes skin aging by week 8. The effect of a high salt diet on skin aging is related to the level of oxidative stress and the expression of cell cycle inhibitors. Additionally, a potential protective mechanism may be at play, as evidenced by the reduced ET-1/NO ratio, which could help counteract the hypercoagulable state and support nutrient delivery to aging skin.

Targeting senescence has emerged as a promising strategy for liver cancer treatment. However, the lack of a safe agent capable of inducing complete senescence and being combined with senolytics poses a limitation. Here, we screened a natural product library and identified tryptanthrin (TRYP) as a potent inducer of cellular senescence in liver cancer cells both in vitro and in vivo. Mechanistically, Glutathione S-transferase P1 (GSTP1), a key regulator for redox homeostasis, was identified as a target protein for TRYP-induced senescence. TRYP directly bound to GSTP1 and inhibited its enzymatic activity, mediating reactive oxygen species (ROS) accumulation, followed by DNA damage response (DDR), consequently contributing to initiating primary senescence. Furthermore, TRYP triggered DNA damage-dependent activation of NF-κB pathway, which evoked senescence-associated secretory phenotype (SASP), thereby leading to senescence reinforcement. Importantly, TRYP exposed the vulnerability of tumor cells and sensitized senescent cells to apoptosis induced by senolytic agent ABT263, a Bcl2 inhibitor. Taken together, our findings reveal that TRYP induces cellular senescence via GSTP1/ROS/DDR/NF-κB/SASP axis, providing a novel potential application in synergizing with senolytic therapy in liver cancer.

Abstract Tumour cell senescence can be induced by various factors, including DNA damage, inflammatory signals, genetic toxins, ionising radiation and nutrient metabolism. The senescence‐associated secretory phenotype (SASP), secreted by senescent tumour cells, possesses the capacity to modulate various immune cells, including macrophages, T cells, natural killer cells and myeloid‐derived suppressor cells, as well as vascular endothelial cells and fibroblasts within the tumour microenvironment (TME), and this modulation can result in either the promotion or suppression of tumorigenesis and progression. Exploring the impact of SASP on the TME could identify potential therapeutic targets, yet limited studies have dissected its functions. In this review, we delve into the causes and mechanisms of tumour cell senescence. We then concentrate on the influence of SASP on the tumour immune microenvironment, angiogenesis, extracellular matrix and the reprogramming of cancer stem cells, along with their associated tumour outcomes. Last, we present a comprehensive overview of the diverse array of senotherapeutics, highlighting their prospective advantages and challenge for the treatment of cancer patients. Key points Senescence‐associated secretory phenotype (SASP) secretion from senescent tumour cells significantly impacts cancer progression and biology. SASP is involved in regulating the remodelling of the tumour microenvironment, including immune microenvironment, vascular, extracellular matrix and cancer stem cells. Senotherapeutics, such as senolytic, senomorphic, nanotherapy and senolytic vaccines, hold promise for enhancing cancer treatment efficacy.