Inhibition of transglutaminase 2 inhibits ionizing radiation-induced cellular senescence in skin keratinocytes in vitro.

Senescent cells are typically characterized by a stable proliferation arrested in dividing cells accompanied with a senescence-associated secretory phenotype (SASP). Skin cellular senescence is the primary cause of skin aging, whereas the lack of identified skin senescence markers limits our understanding of the mechanisms involved in skin aging. Recent studies have revealed that intracellular calcium signaling has emerged as a key player in regulating cellular senescence and aging. However, the implication and roles of calcium signaling in skin keratinocyte senescence remain only partially understood. In this study, we developed a model for skin keratinocyte senescence using ionizing radiation (I/R) stimulation and found that the calcium-associated gene transglutaminase 2 (TGM2) was significantly induced compared with normal control. Interestingly, inhibition of TGM2 was found to delay skin keratinocyte senescence by suppressing I/R-promoted intracellular calcium signaling, accumulation of reactive oxygen species (ROS), DNA damage, as well as NF-κB-mediated SASP secretion. Taken together, our findings demonstrate that inhibition of TGM2 contributes to bypassing I/R-induced skin keratinocyte senescence and sheds light on novel strategies against skin stresses caused by I/R.

Therapy-Induced Cellular Senescence: Potentiating Tumor Elimination or Driving Cancer Resistance and Recurrence?

Cellular senescence has been increasingly recognized as a hallmark of cancer, reflecting its association with aging and inflammation, its role as a response to deregulated proliferation and oncogenic stress, and its induction by cancer therapies. While therapy-induced senescence (TIS) has been linked to resistance, recurrence, metastasis, and normal tissue toxicity, TIS also has the potential to enhance therapy response and stimulate anti-tumor immunity. In this review, we examine the Jekyll and Hyde nature of senescent cells (SnCs), focusing on how their persistence while expressing the senescence-associated secretory phenotype (SASP) modulates the tumor microenvironment through autocrine and paracrine mechanisms. Through the SASP, SnCs can mediate both resistance and response to cancer therapies. To fulfill the unmet potential of cancer immunotherapy, we consider how SnCs may influence tumor inflammation and serve as an antigen source to potentiate anti-tumor immune response. This new perspective suggests treatment approaches based on TIS to enhance immune checkpoint blockade. Finally, we describe strategies for mitigating the detrimental effects of senescence, such as modulating the SASP or targeting SnC persistence, which may enhance the overall benefits of cancer treatment.

Insulin Resistance in Women Correlates with Chromatin Histone Lysine Acetylation, Inflammatory Signaling, and Accelerated Aging.

BACKGROUND: Epigenetic 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. METHODS: Building 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. RESULTS: ChIP-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. CONCLUSIONS: This 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.

Therapy-Induced Senescence: Novel Approaches for Markers Identification.

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.

The emerging importance of lymphangiogenesis in aging and aging-associated diseases.

Lymphatic aging represented by cellular and functional changes, is involved in increased geriatric disorders, but the intersection between aging and lymphatic modulation is less clear. Lymphatic vessels play an essential role in maintaining tissue fluid homeostasis, regulating immune function, and promoting macromolecular transport. Lymphangiogenesis and lymphatic remodeling following cellular senescence and organ deterioration are crosslinked with the progression of some lymphatic-associated diseases, e.g., atherosclerosis, inflammation, lymphoedema, and cancer. Age-related detrimental tissue changes may occur in lymphatic vessels with diverse etiologies, and gradually shift towards chronic low-grade inflammation, so-called inflammaging, and lead to decreased immune response. The investigation of the relationship between advanced age and organ deterioration is becoming an area of rapidly increasing significance in lymphatic biology and medicine. Here we highlight the emerging importance of lymphangiogenesis and lymphatic remodeling in the regulation of aging-related pathological processes, which will help to find new avenues for effective intervention to promote healthy aging.

A Nanocapsule System Combats Aging by Inhibiting Age-Related Angiogenesis Deficiency and Glucolipid Metabolism Disorders.

Insufficient angiogenic stimulation and dysregulated glycolipid metabolism in senescent vascular endothelial cells (VECs) constitute crucial features of vascular aging. Concomitantly, the generation of excess senescence-associated secretory phenotype (SASP) and active immune-inflammatory responses propagates within injured vessels, tissues, and organs. Until now, targeted therapies that efficiently rectify phenotypic abnormalities in senescent VECs have still been lacking. Here, we constructed a Pd/hCeO2-BMS309403@platelet membrane (PCBP) nanoheterostructured capsule system loaded with fatty acid-binding protein 4 (FABP4) inhibitors and modified with platelet membranes and investigated its therapeutic role in aged mice. PCBP showed significant maintenance in aged organs and demonstrated excellent biocompatibility. Through cyclic tail vein administration, PCBP extended the lifespan and steadily ameliorated abnormal phenotypes in aged mice, including SASP production, immune and inflammatory status, and age-related metabolic disorders. In senescent ECs, PCBP mediated the activation of vascular endothelial growth factor (VEGF) signaling and glycolysis and inhibition of FABP4 by inducing the synthesis of hypoxia-inducible factor-1α, thereby reawakening neovascularization and restoring glycolipid metabolic homeostasis. In conclusion, the PCBP nanocapsule system provides a promising avenue for interventions against aging-induced dysfunction.

Construction and validation of a SASP-related prognostic signature in patients with acute myeloid leukaemia.

Acute myeloid leukaemia (AML) is a common and highly aggressive haematological malignancy in adults. Senescence-associated secretory phenotype (SASP) plays important roles in tumorigenesis and progression of tumour. However, the prognostic value of SASP in patients with AML has not been clarified. The present study aims to explore the prognostic value of SASP and develop a prognostic risk signature for AML. The RNA-sequencing data was collected from the TCGA, GTEx and TARGET databases. Subsequently, differentially expressed gene analysis, univariate Cox regression and LASSO regression were applied to identified prognostic SASP-related genes and construct a prognostic risk-scoring model. The risk score of each patient were calculated and patients were divided into high- or low-risk groups by the median risk score. This novel prognostic signature included 11 genes: G6PD, CDK4, RPS6KA1, UBC, H2BC12, KIR2DL4, HSF1, IFIT3, PIM1, RUNX3 and TRIM21. The patients with AML in the high-risk group had shorter OS, demonstrating that the risk score acted as a prognostic predictor, which was validated in the TAGET-AML dataset. Univariate and multivariate analysis revealed the risk score was an independent prognostic factor in patients with AML. Furthermore, the present study revealed that the risk score was associated with immune landscape, immune checkpoint gene expression and chemotherapeutic efficacy. In the present study, we constructed and validated a unique SASP-related prognostic model to assess therapeutic effect and prognosis in patients with AML, which might contribute to understanding the role of SASP in AML and guiding the treatment for AML.

The dual role of cellular senescence in human tumor progression and therapy.

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.

Metformin suppresses esophageal cancer progression through the radiation­induced cellular senescence of cancer­associated fibroblasts.

Senescent cells are known to secrete proteins, including inflammatory cytokines and damage­associated molecular patterns. This phenomenon is known as the senescence­associated secretory phenotype (SASP). SASP in cancer stromal fibroblasts is involved in cancer growth and progression. Conversely, metformin, an antidiabetic drug, has been reported to inhibit SASP induction by inhibiting the activation of NF­κB, a regulator of SASP. To date, at least to the best of our knowledge, there have been no reports regarding cellular senescence in fibroblasts and tumor progression via the SASP­mediated paracrine pathway. The present study thus aimed to elucidate the induction mechanisms of SASP in radiation­induced fibroblasts and to determine its effects on cancer progression via the paracrine pathway. Furthermore, the present study aimed to determine whether controlling SASP using metformin suppresses cancer progression. A well­differentiated esophageal cancer cell line established by the authors' department and fibroblasts isolated and cultured from the non­cancerous esophageal mucosa of resected esophageal cancer cases were used for the experiments. Fibroblasts were irradiated with 8 Gy radiation, and the changes in the expression of the senescence markers, SA­ß­gal, p21, p16 and NF­κB were evaluated using immunofluorescent staining and western blot analysis in the presence or absence of metformin treatment. The culture supernatants of irradiated fibroblasts treated with metformin and those treated without metformin were collected and added to the cancer cells to evaluate their proliferative, invasive and migratory abilities. Vimentin and E­cadherin expression levels were also evaluated using immunofluorescent staining and western blot analysis. The expression levels of p16, p21 and NF­κB in irradiated fibroblasts were attenuated by treatment with metformin. Supernatants collected from irradiated fibroblasts exhibited the proliferative activity of esophageal cancer cells, and the promotion of migratory and invasion abilities, which may be due to epithelial­mesenchymal transition and changes in cell morphology. These reactions were confirmed to be suppressed by the addition of the supernatant of cultured fibroblasts pre­treated with metformin. On the whole, the present study demonstrates that fibroblasts in the cancer stroma may be involved in tumor progression through cellular senescence.

Mentha piperita leaf extract suppresses the release of ATP from epidermal keratinocytes and reduces dermal thinning as well as wrinkle formation.

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.

OBJECTIFS: Pour obtenir une apparence plus belle et plus jeune, réduire les rides est une préoccupation clé. Le processus de formation des rides est complexe et le développement d'ingrédients cosmétiques réellement efficaces pour réduire les rides reste un défi. Des études récentes ont révélé une relation étroite entre les rides et l'amincissement de la peau, suggérant que la prévention de l'amincissement de la peau pourrait également prévenir la formation de rides. Dans cette étude, nous avons examiné le rôle de l'adénosine triphosphate extracellulaire (eATP) dans la progression de l'amincissement, car l'eATP augmente apparemment les facteurs de vieillissement de la peau, tels que les facteurs du phénotype sécrétoire associé à la sénescence (SASP) dans les cellules épidermiques. Nous avons déterminé les effets de l'extrait de feuille de Mentha piperita sur la suppression de l'eATP pour réduire l'amincissement et les rides. MÉTHODES: Les niveaux d'adénosine triphosphate (ATP) ont été mesurés dans les kératinocytes épidermiques humains normaux (NHEK) en présence d'extrait de feuille de M. piperita. La sécheresse, le pH élevé et les radiations UVB ont été utilisés comme facteurs de vieillissement extrinsèque. Le vieillissement intrinsèque de la peau a été évalué en comparant les cellules des adultes (AD­NHEK) et des nouveau­nés (NB­NHEK). Une étude in vivo contrôlée par placebo a été réalisée avec une formulation contenant 1% d'extrait de feuille de M. piperita. RÉSULTATS: Les niveaux d'eATP étaient significativement plus élevés dans les AD­NHEK comparés à ceux des cellules NB­NHEK. L'extrait de feuille de M. piperita a significativement diminué les niveaux d'eATP dans les cellules adultes. Les facteurs de vieillissement extrinsèque ont augmenté les niveaux d'eATP dans les NHEK, tandis que l'extrait de feuille de M. piperita a significativement supprimé l'eATP dans toutes les conditions. Les composants actifs de l'extrait de feuille de M. piperita, la lutéoline glucuronide et l'acide rosmarinique, ont également diminué l'eATP. De plus, comparée à la lotion placebo, la lotion formulée avec de l'extrait de feuille de M. piperita a considérablement augmenté l'épaisseur dermique et réduit les rides associées aux pattes d'oie et à la région du cou. CONCLUSION: Nous avons démontré pour la première fois que l'extrait de feuille de M. piperita contenant de l'acide rosmarinique et de la lutéoline­7­O­glucuronide a le potentiel de réduire la libération d'eATP des kératinocytes épidermiques. Une augmentation de l'eATP a été observée non seulement pendant l'inflammation mais aussi pendant le vieillissement naturel. En outre, l'expérience in vivo révélant que la lotion contenant 1% d'extrait de feuille de M. piperita a amélioré l'amincissement dermique et les rides sur plusieurs zones est attribuée à l'amélioration de l'amincissement dermique. Ainsi, nos données suggèrent la possibilité d'une nouvelle approche cosmétique pour réduire le vieillissement de la peau en réduisant l'amincissement dermique médié par l'eATP.

Exploring the role of cellular senescence in cancer prognosis across multiple tumor types.

Background: Cellular senescence is a common biological process with a well-established link to cancer. However, the impact of cellular senescence on tumor progression remains unclear. To investigate this relationship, we utilized transcriptomic data from a senescence gene set to explore the connection between senescence and cancer prognosis. Methods: We developed the senescence score by the Least Absolute Shrinkage and Selection Operator (LASSO) Cox model. We obtained transcriptomic information of the senescence gene set from The Cancer Genome Atlas (TCGA) program. Additionally, we created a nomogram that integrates these senescence scores with clinical characteristics, providing a more comprehensive tool for prognosis evaluation. Results: We calculated the senescence score based on the expression level of 42 senescence-related genes. We established the nomogram based on the senescence score and clinical characteristics. The senescence score showed a positive correlation with epithelial-to-mesenchymal transition, cell cycle, and glycolysis, and a negative correlation with autophagy. Furthermore, we carried out Gene Ontology (GO) analysis to explore the signaling pathways and biological process in different senescence score groups. Conclusions: The senescence score, a novel tool constructed in this study, shows promise in predicting survival outcomes across various cancer types. These findings not only highlight the complex interplay between senescence and cancer but also indicate that cellular senescence might serve as a biomarker for tumor prognosis.

Long-term culture of patient-derived mammary organoids in non-biogenic electrospun scaffolds for identifying metalloprotein and motor protein activities in aging and senescence.

We recently identified TMEM230 as a master regulator of the endomembrane system of cells. TMEM230 expression is necessary for promoting motor protein dependent intracellular trafficking of metalloproteins for cellular energy production in mitochondria. TMEM230 is also required for transport and secretion of metalloproteinases for autophagy and phagosome dependent clearance of misfolded proteins, defective RNAs and damaged cells, activities that decline with aging. This suggests that aberrant levels of TMEM230 may contribute to aging and regain of proper levels may have therapeutic applications. The components of the endomembrane system include the Golgi complex, other membrane bound organelles, and secreted vesicles and factors. Secreted cellular components modulate immune response and tissue regeneration in aging. Upregulation of intracellular packaging, trafficking and secretion of endosome components while necessary for tissue homeostasis and normal wound healing, also promote secretion of pro-inflammatory and pro-senescence factors. We recently determined that TMEM230 is co-regulated with trafficked cargo of the endomembrane system, including lysosome factors such as RNASET2. Normal tissue regeneration (in aging), repair (following injury) and aberrant destructive tissue remodeling (in cancer or autoimmunity) likely are regulated by TMEM230 activities of the endomembrane system, mitochondria and autophagosomes. The role of TMEM230 in aging is supported by its ability to regulate the pro-inflammatory secretome and senescence-associated secretory phenotype in tissue cells of patients with advanced age and chronic disease. Identifying secreted factors regulated by TMEM230 in young patients and patients of advanced age will facilitate identification of aging associated targets that aberrantly promote, inhibit or reverse aging. Ex situ culture of patient derived cells for identifying secreted factors in tissue regeneration and aging provides opportunities in developing therapeutic and personalized medicine strategies. Identification and validation of human secreted factors in tissue regeneration requires long-term stabile scaffold culture conditions that are different from those previously reported for cell lines used as cell models for aging. We describe a 3 dimensional (3D) platform utilizing non-biogenic and non-labile poly ε-caprolactone scaffolds that supports maintenance of long-term continuous cultures of human stem cells, in vitro generated 3D organoids and patient derived tissue. Combined with animal component free culture media, non-biogenic scaffolds are suitable for proteomic and glycobiological analyses to identify human factors in aging. Applications of electrospun nanofiber technologies in 3D cell culture allow for ex situ screening and the development of patient personalized therapeutic strategies and predicting their effectiveness in mitigating or promoting aging.

Achilles' spear: A new therapeutic target for age-related diseases.

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.

(-)-α-Bisabolol inhibits D-Gal-induced HSF cellular senescence in vitro and prevents skin aging in vivo by reducing SASP.

Objectives: 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 ß-galactosidase staining was utilized to evaluate the senescence of HSF. TNF-α, IL-6, IL-8, IL-1ß, 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 ß-galactosidase (SA-ß-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-ß-gal and SASP factors in vitro. Improved skin barrier function as well as SASP is responsible for the delay of skin aging in vivo.

Methods to Investigate the Secretome of Senescent Cells.

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.

Endometrial senescence is mediated by interleukin 17 receptor B signaling.

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 IL1ß. Of these cytokines, IL1ß 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, IL1ß exposure significantly reduced organoid-forming capacity and increased p21 expression in endometrial organoids relative to non-exposure (control), but when IL1ß 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 IL1ß inhibits cell proliferation and leads to endometrial senescence via the JNK pathway.

FOXO4-DRI improves spermatogenesis in aged mice through reducing senescence-associated secretory phenotype secretion from Leydig cells.

Male ageing is always accompanied by decreased fertility. The forkhead O (FOXO) transcription factor FOXO4 is reported to be highly expressed in senescent cells. Upon activation, it binds p53 in the nucleus, preventing senescent cell apoptosis and maintaining senescent cells in situ. Leydig cells play key roles in assisting spermatogenesis. Leydig cell senescence leads to deterioration of the microenvironment of the testes and impairs spermatogenesis. In this study, we observed that FOXO4-DRI, a specific FOXO4- p53 binding blocker, induced apoptosis in senescent Leydig cells, reduced the secretion of certain Senescence-Associated Secretory Phenotype and improved the proliferation of cocultured GC-1 SPG cells. In naturally aged mice, FOXO4-DRI-treated aged mice exhibited increased sperm quality and improved spermatogenesis.

Cellular Senescence and Extracellular Vesicles in the Pathogenesis and Treatment of Obesity-A Narrative Review.

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 ß 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 ß-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.

Chronic inflammation with microglia senescence at basal forebrain: impact on cholinergic deficit in Alzheimer's brain haemodynamics.

Cholinergic innervation in the brain is involved in modulating neurovascular function including cerebral blood flow haemodynamics in response to neuronal activity. Cholinergic deficit is associated with pathophysiology in Alzheimer's disease, albeit the aetiology remains to be clarified. In the current study, neocortex cerebral blood flow response to acetylcholine was evaluated by Laser-Doppler Flowmetry (LDF) in 3xTgAD Alzheimer's disease model) and wild-type mice of two age groups. The peak of cerebral blood flow to acetylcholine (i.v.) from baseline levels (% ΔrCBF) was higher in young 3xTgAD versus in wild-type mice (48.35; 95% CI:27.03-69.67 versus 22.70; CI:15.5-29.91, P < 0.05); this was reversed in old 3xTgAD mice (21.44; CI:2.52-40.35 versus 23.25; CI:23.25-39). Choline acetyltransferase protein was reduced in neocortex, while cerebrovascular reactivity to acetylcholine was preserved in young 3×TgAD mice. This suggests endogenous acetylcholine deficit and possible cholinergic denervation from selected cholinergic nuclei within the basal forebrain. The early deposition of tauopathy moieties (mutant hTau and pTau181) and its coincidence in cholinergic cell clusters (occasionaly), were observed at the basal forebrain of 3xTgAD mice including substantia innominate, nucleus Basalis of Meynert and nucleus of horizontal limb diagonal band of Broca. A prominent feature was microglia interacting tauopathy and demonstrated a variety of morphology changes particularly when located in proximity to tauopathy. The microglia ramified phenotype was reduced as evaluated by the ramification index and Fractal analysis. Increased microglia senescence, identified as SASP (senescence-associated secretory phenotype), was colocalization with p16Ink4ɑ, a marker of irreversible cell-cycle arrest in old 3xTgAD versus wild-type mice (P = 0.001). The p16Ink4ɑ was also observed in neuronal cells bearing tauopathy within the basal forebrain of 3xTgAD mice. TNF-ɑ, the pro-inflammatory cytokine elevated persistently in microglia (Pearson's correlation coefficient = 0.62) and the loss of cholinergic cells in vulnerable basal forebrain environment, was indicated by image analysis in 3xTgAD mice, which linked to the cholinergic deficits in neocortex rCBF haemodynamics. Our study revealed the early change of CBF haemodynamics to acetylcholine in 3xTgAD model. As a major effector of brain innate immune activation, microglia SASP with age-related disease progression is indicative of immune cell senescence, which contributes to chronic inflammation and cholinergic deficits at the basal forebrain. Targeting neuroinflammation and senescence may mitigate cholinergic pathophysiology in Alzheimer's disease.

Mitochondrial Quality Control Processes at the Crossroads of Cell Death and Survival: Mechanisms and Signaling Pathways.

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.