Protocols to detect senescence-associated beta-galactosidase (SA-betagal) activity, a biomarker of senescent cells in culture and in vivo. Nat Protoc. 2009;4:1798-1806. [PMID: 20010931 DOI: 10.1038/nprot.2009.191]

Targeting ATAD3A Phosphorylation Mediated by TBK1 Ameliorates Senescence-Associated Pathologies

Targeting cellular senescence, one of the hallmarks of aging and aging-related pathologies emerges as an effective strategy for anti-aging and cancer chemotherapy. Here, a switch from TBK1-OPTN axis to TBK1-ATAD3A axis to promote cellular senescence is shown. Mechanically, TBK1 protein is abnormally activated and localized to the mitochondria during senescence, which directly phosphorylates ATAD3A at Ser321. Phosphorylated ATAD3A is significantly elevated in cellular senescence as well as in physiological and pathological aging and is essential for suppressing Pink1-mediated mitophagy by facilitating Pink1 mitochondrial import. Inhibition of ATAD3A phosphorylation at Ser321 by either TBK1 deficiency or by a Ser321A mutation rescues the cellular senescence. A blocking peptide, TAT-PEP, specifically abrogating ATAD3A phosphorylation, results in elevated cell death by preventing doxorubicin-induced senescence, thus leading to enhanced tumor sensitivity to chemotherapy. TAT-PEP treatment also ameliorates various phenotypes associated with physiological aging. Collectively, these results reveal the TBK1-ATAD3A-Pink1 axis as a driving force in cellular senescence and suggest a potential mitochondrial target for anti-aging therapy.

Photothermal Nano-Immunotherapy Against Methicillin-Resistant Staphylococcus aureus (MRSA) Biofilm Infections

Methicillin-resistant Staphylococcus aureus (MRSA) biofilm infections are a prevalent type of biofilm-associated infection with a poor prognosis and antibiotic resistance. The senescence of immune cells in the immune microenvironment contributes to biofilm formation. In this study, Ti₃C₂ MXene-PVA nanosheets loaded with metformin (Met@TiC) are developed for the treatment of MRSA biofilm infections. Nanosheets utilize near-infrared light to induce photothermal effects and provide direct bactericidal activity against biofilm structures. Met, which is known for its anti-inflammatory and anti-senescence properties, modulates immune responses by revitalizing the function of senescent macrophages within the biofilm microenvironment, thereby enhancing their phagocytic and biofilm-eradicating capabilities. The efficacy of this nanoplatform both in vitro and in an MRSA biofilm infection mouse model, demonstrating its potential as a photothermal nanoimmunotherapy for combating MRSA biofilm infections is validated. In summary, the Met@TiC nanoplatform offers a significant alternative to clinical solutions for MRSA biofilm infections.

Natural Product-Derived Senotherapeutics: Extraction and Biological Evaluation Techniques

Selective targeting of senescent cells has been thus far considered a widespread preventive strategy, as well as a main or adjuvant therapy for age-associated diseases, fueling the research on the discovery of senotherapeutics (i.e., senolytic or senomorphic compounds). Given that until now no single senotherapeutic has been reported to exert a universal anti-senescence action due to the cell- /tissue-, and context-dependent specificity of such compounds, seeking novel selective senotherapeutics remains of great importance. In this chapter, a research strategy that could be followed to screen natural product collections for putative senotherapeutics with enhanced specificity and reduced toxicity is presented, from the extraction of the source material and the isolation and chemical characterization of the compounds of interest to their biological evaluation in vitro and in vivo.

The crosstalk between senescence, tumor, and immunity: molecular mechanism and therapeutic opportunities

Cellular senescence is characterized by a stable cell cycle arrest and a hypersecretory, proinflammatory phenotype in response to various stress stimuli. Traditionally, this state has been viewed as a tumor-suppressing mechanism that prevents the proliferation of damaged cells while activating the immune response for their clearance. However, senescence is increasingly recognized as a contributing factor to tumor progression. This dual role necessitates a careful evaluation of the beneficial and detrimental aspects of senescence within the tumor microenvironment (TME). Specifically, senescent cells display a unique senescence-associated secretory phenotype that releases a diverse array of soluble factors affecting the TME. Furthermore, the impact of senescence on tumor-immune interaction is complex and often underappreciated. Senescent immune cells create an immunosuppressive TME favoring tumor progression. In contrast, senescent tumor cells could promote a transition from immune evasion to clearance. Given these intricate dynamics, therapies targeting senescence hold promise for advancing antitumor strategies. This review aims to summarize the dual effects of senescence on tumor progression, explore its influence on tumor-immune interactions, and discuss potential therapeutic strategies, alongside challenges and future directions. Understanding how senescence regulates antitumor immunity, along with new therapeutic interventions, is essential for managing tumor cell senescence and remodeling the immune microenvironment.

Senolytics cocktail dasatinib and quercetin alleviate chondrocyte senescence and facet joint osteoarthritis in mice

BACKGROUND CONTEXT

Low back pain (LBP) is a pervasive issue, causing substantial economic burden and physical distress worldwide. Facet joint osteoarthritis (FJ OA) is believed to be a significant contributor to this problem. However, the precise role of chondrocyte senescence in FJ OA remains unclear, as does whether the clearance of chondrocyte senescence can alleviate the progression of FJ OA.

PURPOSE

The goal of this study was to understand the potential of Dasatinib (D) and Quercetin (Q) as a treatment to clear chondrocyte senescence during the progression of FJ OA.

STUDY DESIGN

We used a preclinical bipedal standing mice model with the administration of Dasatinib (D) (5 mg/kg) and Quercetin (Q) (50 mg/kg) after 10 weeks of bipedal standing.

MATERIALS AND METHODS

Human degenerative lumbar facet joint (LFJ) samples were obtained to investigate the relationship between chondrocyte cellular senescence and LFJ osteoarthritis (OA). Subsequently, we established an in vitro model of excessive mechanical stress on chondrocytes and an in vivo bipedal standing mice model to induce LFJ OA. IHC (immunohistochemistry) staining in vivo and SA-β-gal staining, qRT-PCR and Western blot analysis were applied to test the senolytic effect of the combination of Dasatinib (D) and Quercetin (Q). IHC staining and X-ray microscope were also performed to examine the contribution of D+Q to the anabolism in cartilage and subchondral bone recoupling. Immunofluorescence and Western blot analysis in vitro and IHC staining in vivo were conducted to assess the impact of D+Q on the regulation of the NF-κB pathway activation during chondrocyte senescence.

RESULTS

We observed that facet joint cartilage degeneration is associated with chondrocyte cellular senescence in both human and mouse degenerative samples. Following treatment with D+Q in vitro, cellular senescence was significantly reduced. Upon oral gavage administration of D+Q in the bipedal standing mice model, decreased cellular senescence and reversed chondrocyte anabolism were observed. Furthermore, administration of D+Q maintained subchondral bone remodeling homeostasis and potentially reversed the activation of the NF-κB pathway in chondrocytes of the lumbar facet joint.

CONCLUSIONS

In summary, our investigation unveiled a significant correlation between chondrocyte senescence and LFJOA. Treatment with the senolytic combination of D+Q in FJ OA yielded a notable reduction in chondrocyte senescence, along with a decrease in the release of SASP factors. Additionally, it facilitated the promotion of cartilage anabolism, maintenance of subchondral bone coupling, and amelioration of NF-κB pathway activation.

CLINICAL SIGNIFICANCE

Our outcomes revealed that D+Q, the renowned combination used for senolytic treatment, alleviate the progression of LFJ OA. The utilization of D+Q as a senolytic demonstrates a novel and promising alternative for LFJ OA treatment.

Studying Cellular Senescence Using the Model Organism Drosophila melanogaster

Cellular senescence, a complex biological process characterized by irreversible cell cycle arrest, contributes significantly to the development and progression of aging and of age-related diseases. Studying cellular senescence in vivo can be challenging due to the high heterogeneity and dynamic nature of senescent cells. Recently, Drosophila melanogaster has emerged as a powerful model organism for studying aging and cellular senescence due to its tractability and short lifespan, as well as due to the conservation of age-related genes and of key age-related pathways with mammals. Consequently, several research studies have utilized Drosophila to investigate the cellular mechanisms and pathways implicated in cellular senescence. Herein, we provide an overview of the assays that can be applied to study the different features of senescent cells in D. melanogaster tissues, highlighting the benefits of this model in aging research. We also emphasize the importance of selecting appropriate biomarkers for the identification of senescent cells, and the need for further understanding of the aging process including a more accurate identification and detection of senescent cells at the organismal level; a far more complex process as compared to single cells.

The DNA Damage Response as an Auxiliary Indicator of Senescence in Cancer: A User-Friendly Toolkit of Markers and Detection Methods

Senescence is a cellular stress response causing a stable exit from the cell cycle. Limitation of cell proliferation is accompanied by a variety of characteristic changes, including cellular and nuclear morphological alterations, chromatin rearrangements, metabolic reprogramming, nuclear envelope rupture, and an immunomodulatory secretome, termed senescence-associated secreted phenotype (SASP). Senescence is a robust mechanism of tissue homeostasis, with crucial roles in eliminating dysfunctional and/or premalignant cells, and tissue repair. Activation of oncogenes triggers senescence, which in turn arrests DNA-damaged cells. This type of response, known as oncogene-induced senescence (OIS) is a powerful barrier to oncogenesis. However, in specific contexts, senescent cells support tumor progression, mainly via their secretome-mediated activities. The dynamic, context-dependent and ambivalent nature of senescence challenges the identification, characterization, and specific targeting of senescent cells for disease management. Importantly, senescence is highly intertwined with DNA damage response and repair (DDR/R) machinery that safeguards genome integrity. DNA damage events are frequently prevalent, while DDR/R signaling pathways are active during cellular senescence. In this regard, it can serve as an auxiliary indicator for senescent cells. In this chapter, we emphasize DDR/R as a shared hallmark of cancer and senescence. We provide a wieldy toolkit of experimental methods for monitoring DDR-related senescence markers, and we demonstrate the potential of using natural language processing to extract additional DDR/R biomarkers tailored to specific cancer types. Our methodologies can facilitate a comprehensive study of senescence in aging and cancer.

Increased inflammation in older high-pressure glaucoma mice

Besides an elevated intraocular pressure (IOP), advanced age is one of the most crucial risk factors for developing glaucoma. βB1-Connective Tissue Growth Factor (βB1-CTGF) high-pressure glaucoma mice were used in this study to assess whether glaucoma mice display more inflammatory and aging processes than age-matched controls. Therefore, 20-month-old βB1-CTGF and corresponding wildtype (WT) controls were examined. After IOP measurements, retinas were processed for (immuno-)histological and quantitative real-time PCR analyses. A significantly higher IOP and diminished retinal ganglion cell numbers were noted in βB1-CTGF mice compared to WT. An enhanced macrogliosis as well as an increased number of microglia/macrophages and microglia was detected in retinas of old glaucoma mice. Interleukin (IL)-1β, IL-6, tumor necrosis factor-α, and transforming growth factor-β2 were upregulated, suggesting an ongoing inflammation. Moreover, βB1-CTGF retinas displayed an increased senescence-associated β-galactosidase staining accompanied by a downregulation of Lmnb1 (laminin-B1) mRNA levels. Our results provide a deeper insight into the association between inflammation and high-pressure glaucoma and thus might help to develop new therapy strategies.

PARP inhibition radiosensitizes BRCA1 wildtype and mutated breast cancer to proton therapy

Aggressive breast cancers often fail or acquire resistance to radiotherapy. To develop new strategies to improve the outcome of aggressive breast cancer patients, we studied how PARP inhibition radiosensitizes breast cancer models to proton therapy, which is a radiotherapy modality that generates more DNA damage in the tumor than standard radiotherapy using photons. Two human BRCA1-mutated breast cancer cell lines and their isogenic BRCA1-recovered pairs were treated with a PARP inhibitor and irradiated with photons or protons. Protons (9.9 and 3.85 keV/µm) induced higher cell kill independent of BRCA1 status. PARP inhibition amplified the cell kill effect to both photons and protons (9.9 and 3.85 keV/µm) independent of BRCA1 status. Numbers of γH2AX foci, micronuclei, and cGAS-positive micronuclei were significantly higher in BRCA1-mutated cells. Cell cycle distribution and stress-induced senescence were not affected by PARP inhibition in our cell lines. In vivo, the combination of protons (3.99 keV/µm) and PARP inhibition induced the greatest tumor growth delay and the highest survival. We found that PARP inhibition increases radiosensitization independent of BRCA1 status for both protons and photons. The combination of protons and PARP inhibition was the most effective in decreasing clonogenic cell survival, increasing DNA damage, and delaying tumor growth.

TRPC1 links calcium signaling to cellular senescence in the protection against posttraumatic osteoarthritis

Transient receptor potential channel 1 (TRPC1) is a widely expressed mechanosensitive ion channel located within the endoplasmic reticulum membrane, crucial for refilling depleted internal calcium stores during activation of calcium-dependent signaling pathways. Here, we have demonstrated that TRPC1 activity is protective within cartilage homeostasis in the prevention of cellular senescence-associated cartilage breakdown during mechanical and inflammatory challenge. We revealed that TRPC1 loss is associated with early stages of osteoarthritis (OA) and plays a nonredundant role in calcium signaling in chondrocytes. Trpc1-/- mice subjected to destabilization of the medial meniscus-induced OA developed a more severe OA phenotype than WT controls. During early OA development, Trpc1-/- mice displayed an increased chondrocyte survival rate; however, remaining cells displayed features of senescence including p16INK4a expression and decreased Sox9. RNA-Seq identified differentially expressed genes related to cell number, apoptosis, and extracellular matrix organization. Trpc1-/- chondrocytes exhibited accelerated dedifferentiation, while demonstrating an increased susceptibility to cellular senescence. Targeting the mechanism of TRPC1 activation may be a promising therapeutic strategy in OA prevention.

Immune aging and infectious diseases

ABSTRACT

The rise in global life expectancy has led to an increase in the older population, presenting significant challenges in managing infectious diseases. Aging affects the innate and adaptive immune systems, resulting in chronic low-grade inflammation (inflammaging) and immune function decline (immunosenescence). These changes would impair defense mechanisms, increase susceptibility to infections and reduce vaccine efficacy in older adults. Cellular senescence exacerbates these issues by releasing pro-inflammatory factors, further perpetuating chronic inflammation. Moreover, comorbidities, such as cardiovascular disease and diabetes, which are common in older adults, amplify immune dysfunction, while immunosuppressive medications further complicate responses to infections. This review explores the molecular and cellular mechanisms driving inflammaging and immunosenescence, focusing on genomic instability, telomere attrition, and mitochondrial dysfunction. Additionally, we discussed how aging-associated immune alterations influence responses to bacterial, viral, and parasitic infections and evaluated emerging antiaging strategies, aimed at mitigating these effects to improve health outcomes in the aging population.

Quercetin preserves mitochondria-endoplasmic reticulum contact sites improving mitochondrial dynamics in aged myocardial cells

Cardiomyocyte senescence plays a crucial role in the pathophysiology of age-related cardiovascular disease. Senescent cells with impaired contractility, mitochondrial dysfunction, and hypertrophic growth accumulate in the heart during aging, contributing to cardiac dysfunction and remodeling. Mitochondrial dynamics is altered in aging cells, leading to changes in their function and morphology. Such rearrangements can affect the spatially restricted region of the mitochondrial membrane that interacts with reticulum membrane fragments, termed mitochondria-endoplasmic reticulum (ER) contact sites (MERCs). Besides, oxidative stress associated with inefficient organelle turnover can drive cellular senescence. Therefore, in this study, we evaluated the possible association between the senolytic effect of the antioxidant quercetin (Q) and MERCs preservation in a D-galactose-induced cellular senescence model. We found that Q ameliorates the senescent phenotype of H9c2 cells in association with increased mitochondria-ER colocalization, reduced distance between both organelles, and lower ROS production. Moreover, regulation of fusion and fission processes was related with increased mitochondrial ATP production and enhanced transmembrane potential. Overall, our data provide evidence that the inhibitory effect of Q on cellular senescence is associated with preserved MERCs and improved mitochondrial function and morphology, which might contribute to the attenuation of cardiac dysfunction.

Fluorogenic Labeling Probe for the Imaging of Endogenous β-Galactosidase Activity in Cancer and Senescent Cells

The sensitive detection of glycosidases in live cells is crucial to understanding their functional roles in disease progression. Here, we develop a fluorogenic labeling probe for β-galactosidase (β-Gal) based on a bright green-emitting fluorescent dye, fluorescein. Galactose was introduced to a fluoromethyl-substituted fluorescein derivative through a benzyl spacer, resulting in a quenched fluorescence due to spirocyclization of the dye. After removal of the galactosyl residue by β-Gal, an ∼210-fold enhanced green fluorescence (emission maximum at 524 nm) was detected, and the presence of other glycosidases and hydrolases did not produce false-positive signals. The probe was successfully used for imaging of the endogenous β-Gal activity in cancer and senescent cells, and the imaging results agree with the β-Gal expression level of the cells, as determined by Western blotting and polymerase chain reaction. Importantly, we demonstrated that upon hydrolysis of galactose, the fluoromethyl-substituted fluorescein derivative is covalently attached to adjacent proteins, both in solution and in live cells. This study offers a small-molecule probe for the sensitive monitoring of endogenous glycosidase activity.

Human Liver MSCs Retain Their Basic Cellular Properties in Chronically Inflamed Liver Tissue

Every 25th death worldwide is associated with liver pathology. The development of novel approaches to liver diseases therapy and protocols for maintaining the vital functions of patients on the liver transplant waiting list are urgently needed. Resident mesenchymal stem cells (MSCs) play a significant role in supporting liver tissue integrity and improve the liver condition after infusion. However, it remains unclear whether MSCs isolated from chronically inflamed livers are similar in their basic cellular properties to MSCs obtained from healthy livers. We applied a large array of tests to compare resident MSCs isolated from apparently normal liver tissue and from chronically inflamed livers of patients with fibrosis, cirrhosis, and viral hepatitis. Chronic inflammatory environment did not alter the major cellular characteristics of MSCs, including the expression of MSC markers, stem cell markers, adhesion molecules, and the hallmarks of senescence, as well as cell proliferation, migration, and secretome. Only the expression of some immune checkpoints and toll-like receptors was different. Evidently, MSCs with unchanged cellular properties are present in human liver even at late stages of inflammatory diseases. These cells can be isolated and used as starting material in the development of cell therapies of liver diseases.

Extraction, purification, structural identification, and anti-senescent activity of novel pearl peptides on human dermal fibroblasts

The purpose of the present study was to prepare novel anti-senescent peptides from pearls, characterize their primary sequence and secondary structure, and investigate their protective effects and molecular mechanisms towards D-galactose (D-gal)-induced senescence on human dermal fibroblasts (HDFs). Novel pearl peptides with a purity of 96.58 % and maximum yield of 3.29 % were obtained using ultrasonic-assisted acetic acid extraction strategy under the optimal extraction conditions (ultrasonic power 200 W, ultrasonic time 70 min, and the ratio of pearl powder to acetic acid 1:20). It is sequenced mainly as five novel anti-senescent peptides with molecular weight < 2000 Da, and consisted of β-sheet (43.2 %), random coil (32.1 %), β-turn (21.2 %) and α-helix (3.5 %) analyzed by LC-MS/MS, FT-IR and CD spectroscopy. Further anti-senescent experiments showed that pearl peptides can increase cell viability, restore DNA damage, and suppress the accumulation of ROS as well as senescence-associated-β-galactosidase (SA-β-gal). The molecular mechanism may be that pearl peptides down-regulate the gene and protein expressions of senescence-associated proteins p53, p21, and p16. Therefore, novel pearl peptides could be developed as functional foods or nutritional supplements for the prevention of skin aging.

Multifunctional Hydrogel Microneedle Patches Modulating Oxi-inflamm-aging for Diabetic Wound Healing

Oxidative stress, chronic inflammation, and immune senescence are important pathologic factors in diabetic wound nonhealing. This study loads taurine (Tau) into cerium dioxide (CeO2) to develop CeO2@Tau nanoparticles with excellent antioxidant, anti-inflammatory, and anti-aging properties. To enhance the drug penetration efficiency in wounds, CeO2@Tau is encapsulated in gelatin methacryloyl (GelMA) hydrogel to prepare CeO2@Tau@Hydrogel@Microneedle (CTH@MN) patch system. Microneedle technology achieves precise and efficient delivery of CeO2@Tau, ensuring their deep penetration into the wound tissue for optimal efficacy. Rigorous in vitro and in vivo tests have confirmed the satisfactory therapeutic effect of CTH@MN patch on diabetic wound healing. Mechanistically, CTH@MN attenuates oxidative damage and inflammatory responses in macrophages by inhibiting the ROS/NF-κB signaling pathway. Meanwhile, CTH@MN activated autophagy-mediated anti-aging activity, creating a favorable immune microenvironment for tissue repair. Notably, in a diabetic mouse wound model, the multifunctional CTH@MN patch significantly promotes wound healing by systematically regulating the oxidation-inflammation-aging (oxi-inflamm-aging) pathological axis. In conclusion, the in-depth exploration of the CTH@MN system in this study provides new strategies and perspectives for treating diabetic non-healing wounds.

Biomarkers for aging of blood - how transferable are they between mice and humans?

Aging significantly impacts the hematopoietic system, reducing its regenerative capacity and ability to restore homeostasis after stress. Mouse models have been invaluable in studying this process due to their shorter lifespan and the ability to explore genetic, treatment, and environmental influences on aging. However, not all aspects of aging are mirrored between species. This review compares three key aging biomarkers in the hematopoietic systems of mice and humans: myeloid bias, telomere attrition, and epigenetic clocks. Myeloid bias, marked by an increased fraction of myeloid cells and decreased lymphoid cells, is a significant aging marker in mice but is scarcely observed in humans after childhood. Conversely, telomere length is a robust aging biomarker in humans, whereas mice exhibit significantly different telomere dynamics, making telomere length less reliable in the murine system. Epigenetic clocks, based on DNA methylation changes at specific genomic regions, provide precise estimates of chronologic age in both mice and humans. Notably, age-associated regions in mice and humans occur at homologous genomic locations. Epigenetic clocks, depending on the epigenetic signatures used, also capture aspects of biological aging, offering powerful tools to assess genetic and environmental impacts on aging. Taken together, not all blood aging biomarkers are transferable between mice and humans. When using murine models to extrapolate human aging, it may be advantageous to focus on aging phenomena observed in both species. In conclusion, although mouse models offer significant insights, selecting appropriate biomarkers is crucial for translating findings to human aging.

Senescence-like Phenotype After Chronic Exposure to Isoproterenol in Primary Quiescent Immune Cells

Chronic stress is associated with a higher risk for carcinogenesis as well as age-related diseases and immune dysfunction. There is evidence showing that psychological stress can contribute to premature immunosenescence. Therefore, the question arose whether chronic exposure to catecholamine could drive immune cells into senescence. Peripheral blood mononuclear cells were isolated from whole blood. After repeated ex vivo treatment with isoproterenol, an epinephrine analog, well-established senescence biomarkers were assessed. We found (i) DNA double-strand break induction, (ii) telomere shortening, (iii) failure to proliferate, (iv) higher senescence-associated β-galactosidase activity, (v) decreases in caspases 3 and 7 activity, and (vi) strong upregulation of the proteoglycan versican accompanied by increased cellular adhesion suggesting the induction of a senescence-like phenotype. These results emphasize the complexity of the effect of isoproterenol on multiple cellular processes and provide insights into the molecular mechanisms of stress leading to immunosenescence.

Spatial transcriptomic landscape unveils immunoglobin-associated senescence as a hallmark of aging

To systematically characterize the loss of tissue integrity and organ dysfunction resulting from aging, we produced an in-depth spatial transcriptomic profile of nine tissues in male mice during aging. We showed that senescence-sensitive spots (SSSs) colocalized with elevated entropy in organizational structure and that the aggregation of immunoglobulin-expressing cells is a characteristic feature of the microenvironment surrounding SSSs. Immunoglobulin G (IgG) accumulated across the aged tissues in both male and female mice, and a similar phenomenon was observed in human tissues, suggesting the potential of the abnormal elevation of immunoglobulins as an evolutionarily conserved feature in aging. Furthermore, we observed that IgG could induce a pro-senescent state in macrophages and microglia, thereby exacerbating tissue aging, and that targeted reduction of IgG mitigated aging across various tissues in male mice. This study provides a high-resolution spatial depiction of aging and indicates the pivotal role of immunoglobulin-associated senescence during the aging process.

Chronic interferon-stimulated gene transcription promotes oncogene-induced breast cancer

The MRE11 complex (comprising MRE11, RAD50, and NBS1) is integral to the maintenance of genome stability. We previously showed that a hypomorphic Mre11 mutant mouse strain (Mre11 ATLD1/ATLD1 ) was highly susceptible to oncogene-induced breast cancer. Here we used a mammary organoid system to examine which MRE11-dependent responses are tumor-suppressive. We found that Mre11 ATLD1/ATLD1 organoids exhibited an elevated interferon-stimulated gene (ISG) signature and sustained changes in chromatin accessibility. This Mre11 ATLD1/ATLD1 phenotype depended on DNA binding of a nuclear innate immune sensor, IFI205. Ablation of Ifi205 in Mre11 ATLD1/ATLD1 organoids restored baseline and oncogene-induced chromatin accessibility patterns to those observed in WT. Implantation of Mre11 ATLD1/ATLD1 organoids and activation of the oncogene led to aggressive metastatic breast cancer. This outcome was reversed in implanted Ifi205 -/- Mre11 ATLD1/ATLD1 organoids. These data reveal a connection between innate immune signaling and tumor development in the mammary epithelium. Given the abundance of aberrant DNA structures that arise in the context of genome instability syndromes, the data further suggest that cancer predisposition in those contexts may be partially attributable to chronic innate immune transcriptional programs.

The Combination of Sorafenib and PGV-1 Inhibits the Proliferation of Hepatocellular Carcinoma Through c-Myc Suppression in an Additive Manner: In Vitro Studies

Hepatocellular carcinoma (HCC) is one of the most aggressive types of liver cancer, and it is frequently associated with upregulated c-Myc expression. Sorafenib (Sor) is commonly used to treat HCC, but many patients experienced mild to severe side effects due to prolonged Sor treatment during therapy. It has been known that Pentagamavunone-1 (PGV-1) exhibits a remarkable antiproliferative effect on several cancer cells, yet limited studies have reported its cellular activities in HCC. The current study aims to evaluate the anticancer effects of Sor in combination with PGV-1 on the progression of HCC proliferation. c-Myc expressing cells, JHH-7 and Huh-7, were used for this study, then Sor and PGV-1 were tested for their effect on the cellular physiology phenomena including cytotoxicity combination assay and colony formation assay, cell cycle profile and reactive oxygen species (ROS) level by flow cytometry, senescence induction by beta-galactosidase (SA-β-gal) assay, and migration inhibition by wound healing assay. The c-Myc expression was evaluated through Western blot. PGV-1 was more effective than Sor at inhibiting cell growth, and it showed greater selectivity for HCC over fibroblast cells. The combination of Sor with PGV-1 exhibited synergistic-additive cytotoxicity with an irreversible effect in HCC cell lines. The combination induced senescence similarly with Sor alone in JHH-7 cells, while PGV-1 enhanced the cellular senescence when combined with Sor in Huh-7 cells. Furthermore, the combination increased ROS level in the same way as PGV-1 did in HCC. The combination with PGV-1 acted better than Sor alone to inhibit JHH-7 cell migration. In addition, the combination treatment led to the suppression of c-Myc, particularly in JHH-7 cells. Taken together, combining Sor with PGV-1 promotes better efficacy than Sor alone to inhibit HCC cell proliferation, and further evaluation of the efficacy and safety of adding PGV-1 to Sor in HCC therapy is worthwhile as a potential combination treatment option.

Decoding senescence of aging single cells at the nexus of biomaterials, microfluidics, and spatial omics

Aging has profound effects on the body, most notably an increase in the prevalence of several diseases. An important aging hallmark is the presence of senescent cells that no longer multiply nor die off properly. Another characteristic is an altered immune system that fails to properly self-surveil. In this multi-player aging process, cellular senescence induces a change in the secretory phenotype, known as senescence-associated secretory phenotype (SASP), of many cells with the intention of recruiting immune cells to accelerate the clearance of these damaged senescent cells. However, the SASP phenotype results in inducing secondary senescence of nearby cells, resulting in those cells becoming senescent, and improper immune activation resulting in a state of chronic inflammation, called inflammaging, in many diseases. Senescence in immune cells, termed immunosenescence, results in further dysregulation of the immune system. An interdisciplinary approach is needed to physiologically assess aging changes of the immune system at the cellular and tissue level. Thus, the intersection of biomaterials, microfluidics, and spatial omics has great potential to collectively model aging and immunosenescence. Each of these approaches mimics unique aspects of the body undergoes as a part of aging. This perspective highlights the key aspects of how biomaterials provide non-cellular cues to cell aging, microfluidics recapitulate flow-induced and multi-cellular dynamics, and spatial omics analyses dissect the coordination of several biomarkers of senescence as a function of cell interactions in distinct tissue environments. An overview of how senescence and immune dysregulation play a role in organ aging, cancer, wound healing, Alzheimer's, and osteoporosis is included. To illuminate the societal impact of aging, an increasing trend in anti-senescence and anti-aging interventions, including pharmacological interventions, medical procedures, and lifestyle changes is discussed, including further context of senescence.

Emerging insights in senescence: pathways from preclinical models to therapeutic innovations

Senescence is a crucial hallmark of ageing and a significant contributor to the pathology of age-related disorders. As committee members of the young International Cell Senescence Association (yICSA), we aim to synthesise recent advancements in the identification, characterisation, and therapeutic targeting of senescence for clinical translation. We explore novel molecular techniques that have enhanced our understanding of senescent cell heterogeneity and their roles in tissue regeneration and pathology. Additionally, we delve into in vivo models of senescence, both non-mammalian and mammalian, to highlight tools available for advancing the contextual understanding of in vivo senescence. Furthermore, we discuss innovative diagnostic tools and senotherapeutic approaches, emphasising their potential for clinical application. Future directions of senescence research are explored, underscoring the need for precise, context-specific senescence classification and the integration of advanced technologies such as machine learning, long-read sequencing, and multifunctional senoprobes and senolytics. The dual role of senescence in promoting tissue homoeostasis and contributing to chronic diseases highlights the complexity of targeting these cells for improved clinical outcomes.

Effect of senolytic drugs in young female mice chemically induced to estropause

AIMS

This study aimed to assess metabolic responses and senescent cell burden in young female mice induced to estropause and treated with senolytic drugs.

MAIN METHODS

Estropause was induced by 4-vinylcyclohexene diepoxide (VCD) injection in two-month-old mice. The senolytics dasatinib and quercetin (D + Q) or fisetin were given by oral gavage once a month from five to 11 months of age.

KEY FINDINGS

VCD-induced estropause led to increased body mass and reduced albumin concentrations compared to untreated cyclic mice, without affecting insulin sensitivity, lipid profile, liver enzymes, or total proteins. Estropause decreased catalase activity in adipose tissue but had no significant effect on other redox parameters in adipose and hepatic tissues. Fisetin treatment reduced ROS levels in the hepatic tissue of estropause mice. Estropause did not influence senescence-associated beta-galactosidase activity in adipose and hepatic tissues but increased senescent cell markers and fibrosis in ovaries. Senolytic treatment did not decrease ovarian cellular senescence induced by estropause.

SIGNIFICANCE

Overall, the findings suggest that estropause leads to minor metabolic changes in young females, and the senolytics D + Q and fisetin had no protective effects despite increased ovarian senescence.

Phytocosmetic potential of Blumea balsamifera oil in mitigating UV-induced photoaging: Evidence from cellular and mouse models

ETHNOPHARMACOLOGICAL RELEVANCE

Blumea balsamifera (L.) DC. (BB), the source of Blumea balsamifera oil (BBO), is an aromatic medicinal plant, renowned for its pharmacological properties and its traditional use in Southeast Asian countries such as China, Thailand, Vietnam, Malaysia, and the Philippines for centuries. Traditionally, BB has been used as a raw herbal medicine for treating various skin conditions like eczema, dermatitis, athlete's foot, and wound healing for skin injuries.

AIM OF THE STUDY

This research aimed to explore the inhibitory effects of BBO on skin aging using two models: in vitro analysis with human dermal fibroblasts (HDF) under UVB-induced stress, and in vivo studies on UVA-induced dorsal skin aging in mice. The study sought to uncover the mechanisms behind BBO's anti-aging effects, specifically, its impact on cellular and tissue responses to UV-induced skin aging.

MATERIALS AND METHODS

We applied doses of 10-20 μL/mL of BBO to HDF cells that had been exposed to UVB radiation to simulate skin aging. We measured cell viability, and levels of reactive oxygen species (ROS), SA-β-gal, pro-inflammatory cytokines, and matrix metalloproteinases (MMPs). In addition, we investigated the involvement of mitogen-activated protein kinases (MAPKs) and nuclear factor kappa B (NF-κB) signaling pathways in mediating the anti-aging effects of BBO. Histopathological and biochemical analyses were conducted in a mouse model to examine the effects of BBO on UV-induced photoaging.

RESULTS

UV exposure accelerated aging, and caused cellular damage and inflammatory responses through ROS-mediated pathways. In HDF cells, BBO treatment countered the UVB-induced senescence, and the recovery of cell viability was correlated to notable reductions in SA-β-gal, ROS, pro-inflammatory cytokines, and MMPs. Mechanistically, the anti-aging effect of BBO was associated with the downregulation of the JNK/NF-κB signaling pathways. In the in vivo mouse model, BBO exhibited protective capabilities against UV-induced photoaging, which were manifested by the enhanced antioxidant enzyme activities and tissue remodeling.

CONCLUSIONS

BBO effectively protects fibroblasts from UV-induced photoaging through the JNK/NF-κB pathway. Recovery from photoaging involves an increase in dermal fibroblasts, alleviation of inflammation, accelerated synthesis of antioxidant enzymes, and slowed degradation of ECM proteins. Overall, BBO enhances the skin's defensive capabilities against oxidative stress, underscoring its potential as a therapeutic agent for oxidative stress-related skin aging.

Nordihydroguaiaretic acid microparticles are effective in the treatment of osteoarthritis

Several disease-modifying osteoarthritis (OA) drugs have emerged, but none have been approved for clinical use due to their systemic side effects, short half-life, and rapid clearance from the joints. Nordihydroguaiaretic acid (NDGA), a reactive oxygen species (ROS) scavenger and autophagy inducer, could be a potential treatment for OA. In this report, we show for the first time that sustained delivery of NDGA through polymeric microparticles maintains therapeutic concentrations of drug in the joint and ameliorates post-traumatic OA (PTOA) in a mouse model. In vitro treatment of oxidatively stressed primary chondrocytes from OA patients using NDGA-loaded poly(lactic-co-glycolic acid) (PLGA) microparticles (NDGA-MP) inhibited 15-lipoxygenase, induced autophagy, prevented chondrosenescence, and sustained matrix production. In vivo intra-articular delivery of NDGA-MP was non-toxic and had prolonged retention time (up to 35 days) in murine knee joints. Intra-articular therapy using NDGA-MP effectively reduced cartilage damage and reduced pain in the surgery-induced PTOA mouse model. Our studies open new avenues to modulate the immune environment and treat post-traumatic OA using ROS quenchers and autophagy inducers.

Role of astrocytes in Alzheimer's disease pathogenesis and the impact of exercise-induced remodeling

Alzheimer's disease (AD) is a prevalent and debilitating brain disorder that worsens progressively with age, characterized by cognitive decline and memory impairment. The accumulation of amyloid-beta (Aβ) leading to amyloid plaques and hyperphosphorylation of Tau, resulting in intracellular neurofibrillary tangles (NFTs), are primary pathological features of AD. Despite significant research investment and effort, therapies targeting Aβ and NFTs have proven limited in efficacy for treating or slowing AD progression. Consequently, there is a growing interest in non-invasive therapeutic strategies for AD prevention. Exercise, a low-cost and non-invasive intervention, has demonstrated promising neuroprotective potential in AD prevention. Astrocytes, among the most abundant glial cells in the brain, play essential roles in various physiological processes and are implicated in AD initiation and progression. Exercise delays pathological progression and mitigates cognitive dysfunction in AD by modulating astrocyte morphological and phenotypic changes and fostering crosstalk with other glial cells. This review aims to consolidate the current understanding of how exercise influences astrocyte dynamics in AD, with a focus on elucidating the molecular and cellular mechanisms underlying astrocyte remodeling. The review begins with an overview of the neuropathological changes observed in AD, followed by an examination of astrocyte dysfunction as a feature of the disease. Lastly, the review explores the potential therapeutic implications of exercise-induced astrocyte remodeling in the context of AD.

DNA repair and anti-cancer mechanisms in the long-lived bowhead whale

At over 200 years, the maximum lifespan of the bowhead whale exceeds that of all other mammals. The bowhead is also the second-largest animal on Earth, reaching over 80,000 kg1. Despite its very large number of cells and long lifespan, the bowhead is not highly cancer-prone, an incongruity termed Peto's Paradox2. This phenomenon has been explained by the evolution of additional tumor suppressor genes in other larger animals, supported by research on elephants demonstrating expansion of the p53 gene3-5. Here we show that bowhead whale fibroblasts undergo oncogenic transformation after disruption of fewer tumor suppressors than required for human fibroblasts. However, analysis of DNA repair revealed that bowhead cells repair double strand breaks (DSBs) and mismatches with uniquely high efficiency and accuracy compared to other mammals. The protein CIRBP, implicated in protection from genotoxic stress, was present in very high abundance in the bowhead whale relative to other mammals. We show that CIRBP and its downstream protein RPA2, also present at high levels in bowhead cells, increase the efficiency and fidelity of DNA repair in human cells. These results indicate that rather than possessing additional tumor suppressor genes as barriers to oncogenesis, the bowhead whale relies on more accurate and efficient DNA repair to preserve genome integrity. This strategy which does not eliminate damaged cells but repairs them may be critical for the long and cancer-free lifespan of the bowhead whale.

Cellular Senescence in Diffuse Gliomas: From Physiopathology to Possible Treatments

Cellular senescence in gliomas is a complex process that is induced by aging and replication, ionizing radiation, oncogenic stress, and the use of temozolomide. However, the escape routes that gliomas must evade senescence and achieve cellular immortality are much more complex, in which the expression of telomerase and the alternative lengthening of telomeres, as well as the mutation of some proto-oncogenes or tumor suppressor genes, are involved. In gliomas, these molecular mechanisms related to cellular senescence can have a tumor-suppressing or promoting effect and are directly involved in tumor recurrence and progression. From these cellular mechanisms related to cellular senescence, it is possible to generate targeted senostatic and senolytic therapies that improve the response to currently available treatments and improve survival rates. This review aims to summarize the mechanisms of induction and evasion of cellular senescence in gliomas, as well as review possible treatments with therapies targeting pathways related to cellular senescence.

A Single-Cell Metabolic Profiling Characterizes Human Aging via SlipChip-SERS

Metabolic dysregulation is a key driver of cellular senescence, contributing to the progression of systemic aging. The heterogeneity of senescent cells and their metabolic shifts are complex and unexplored. A microfluidic SlipChip integrated with surface-enhanced Raman spectroscopy (SERS), termed SlipChip-SERS, is developed for single-cell metabolism analysis. This SlipChip-SERS enables compartmentalization of single cells, parallel delivery of saponin and nanoparticles to release intracellular metabolites and to realize SERS detection with simple slipping operations. Analysis of different cancer cell lines using SlipChip-SERS demonstrated its capability for sensitive and multiplexed metabolic profiling of individual cells. When applied to human primary fibroblasts of different ages, it identified 12 differential metabolites, with spermine validated as a potent inducer of cellular senescence. Prolonged exposure to spermine can induce a classic senescence phenotype, such as increased senescence-associated β-glactosidase activity, elevated expression of senescence-related genes and reduced LMNB1 levels. Additionally, the senescence-inducing capacity of spermine in HUVECs and WRL-68 cells is confirmed, and exogenous spermine treatment increased the accumulation and release of H2O2. Overall, a novel SlipChip-SERS system is developed for single-cell metabolic analysis, revealing spermine as a potential inducer of senescence across multiple cell types, which may offer new strategies for addressing ageing and ageing-related diseases.

TNFSF14+ natural killer cells prevent spontaneous abortion by restricting leucine-mediated decidual stromal cell senescence

In preparation for a potential pregnancy, the endometrium of the uterus changes into a temporary structure called the decidua. Senescent decidual stromal cells (DSCs) are enriched in the decidua during decidualization, but the underlying mechanisms of this process remain unclear. Here, we performed single-cell RNA transcriptomics on ESCs and DSCs and found that cell senescence during decidualization is accompanied by increased levels of the branched-chain amino acid (BCAA) transporter SLC3A2. Depletion of leucine, one of the branched-chain amino acids, from cultured media decreased senescence, while high leucine diet resulted in increased senescence and high rates of embryo loss in mice. BCAAs induced senescence in DSCs via the p38 MAPK pathway. In contrast, TNFSF14+ decidual natural killer (dNK) cells were found to inhibit DSC senescence by interacting with its ligand TNFRSF14. As in mice fed high-leucine diets, both mice with NK cell depletion and Tnfrsf14-deficient mice with excessive uterine senescence experienced adverse pregnancy outcomes. Further, we found excessive uterine senescence, SLC3A2-mediated BCAA intake, and insufficient TNFRSF14 expression in the decidua of patients with recurrent spontaneous abortion. In summary, this study suggests that dNK cells maintain senescence homeostasis of DSCs via TNFSF14/TNFRSF14, providing a potential therapeutic strategy to prevent DSC senescence-associated spontaneous abortion.

A defective splicing machinery promotes senescence through MDM4 alternative splicing

Defects in the splicing machinery are implicated in various diseases, including cancer. We observed a general reduction in the expression of spliceosome components and splicing regulators in human cell lines undergoing replicative, stress-induced, and telomere uncapping-induced senescence. Supporting the view that defective splicing contributes to senescence, splicing inhibitors herboxidiene, and pladienolide B induced senescence in normal and cancer cell lines. Furthermore, depleting individual spliceosome components also promoted senescence. All senescence types were associated with an alternative splicing transition from the MDM4-FL variant to MDM4-S. The MDM4 splicing shift was reproduced when splicing was inhibited, and spliceosome components were depleted. While decreasing the level of endogenous MDM4 promoted senescence and cell survival independently of the MDM4-S expression status, cell survival was also improved by increasing MDM4-S. Overall, our work establishes that splicing defects modulate the alternative splicing of MDM4 to promote senescence and cell survival.

Radiation-induced morphea of the breast - characterization and treatment of fibroblast dysfunction with repurposed mesalazine

Radiation-induced morphea (RIM) is a rare complication of radiotherapy presenting as inflammatory fibrosis, most commonly reported in breast cancer patients. As underlying disease mechanisms are not well understood, targeted therapies are lacking. Since fibroblasts are the key mediators of all fibroproliferative diseases, this study aimed to characterize patient-derived fibroblasts to identify therapeutic targets. We studied primary human control and RIM-fibroblasts on a functional and molecular basis, analyzed peripheral blood and tissue samples and conducted, based on our findings, a treatment attempt in one patient. In RIM, we identified a distinct myofibroblast phenotype reflected by increased alpha-smooth-muscle-actin (αSMA) expression, reduced proliferation and migration rates, and overexpression of osteopontin (OPN). Our RNA sequencing identified aberrant Myc activation as a potential disease driver in RIM fibroblasts, similar to previous findings in systemic sclerosis. Treatment with the anti-inflammatory drug mesalazine reversed the myofibroblast phenotype by targeting Myc. Based on these findings, a patient with RIM was successfully treated with mesalazine, resulting in reduced inflammation and pain and tissue softening, while serum OPN was halved. The present study provides a comprehensive characterization of RIM fibroblasts, suggests a disease-driving role for Myc, demonstrates promising antifibrotic effects of mesalazine and proposes OPN as a biomarker for RIM.

Loss of myosin light chain kinase induces the cellular senescence associated secretory phenotype to promote breast epithelial cell migration

Overexpression or activation of oncogenes or loss of tumor-suppressor genes can induce cellular senescence as a defense mechanism against tumor development, thereby maintaining cellular homeostasis. However, cancer cells can circumvent this senescent state and continue to spread. Myosin light chain kinase (MLCK) is downregulated in many breast cancers. Here we report that downregulation of MLCK in normal breast epithelial cells induces a senescence-associated secretory phenotype and stimulates migration. The reduction of MLCK results in increased p21Cip1 expression, dependent on p53 and the AKT-mammalian target of rapamycin pathway. Subsequently, p21Cip1 promotes the secretion of soluble ICAM-1, IL-1α, IL-6 and IL-8, thereby enhancing collective cell migration in a non-cell-autonomous manner. These findings provide new mechanistic insights into the role of MLCK in cellular senescence and cancer progression.

Activatable fluorescent probes for atherosclerosis theranostics

The onset of atherosclerosis (AS) is insidious, and early stage patients have atypical clinical symptoms. After being diagnosed in late stage, it is often prone to sudden and fatal cardiovascular events. Therefore, it is highly desirable to develop precise and efficient diagnosis and therapy strategies of AS. Benefiting from high signal-to-noise ratio, low detection limit, high specificity and sensitivity, a series of activatable fluorescent probes based on atherosclerotic microenvironment have emerged for identification and treatment of AS. In this review, we focus on the atherosclerotic microenvironment and briefly summarize the correlation between the structural transformation and fluorescence signal changes of mono-/double-activatable fluorescent probes upon biomarkers stimulation. Moreover, their cutting-edge progress for AS theranostics is described. Finally, the outlook for activatable theranostic probes based on atherosclerotic microenvironment is discussed to aim at promoting innovative research in imaging-guided precise AS therapy.

Sex-dependent effects in the aged melanoma tumor microenvironment influence invasion and resistance to targeted therapy

There is documented sex disparity in cutaneous melanoma incidence and mortality, increasing disproportionately with age and in the male sex. However, the underlying mechanisms remain unclear. While biological sex differences and inherent immune response variability have been assessed in tumor cells, the role of the tumor-surrounding microenvironment, contextually in aging, has been overlooked. Here, we show that skin fibroblasts undergo age-mediated, sex-dependent changes in their proliferation, senescence, ROS levels, and stress response. We find that aged male fibroblasts selectively drive an invasive, therapy-resistant phenotype in melanoma cells and promote metastasis in aged male mice by increasing AXL expression. Intrinsic aging in male fibroblasts mediated by EZH2 decline increases BMP2 secretion, which in turn drives the slower-cycling, highly invasive, and therapy-resistant melanoma cell phenotype, characteristic of the aged male TME. Inhibition of BMP2 activity blocks the emergence of invasive phenotypes and sensitizes melanoma cells to BRAF/MEK inhibition.

A Two-Photon-Active Zr-Based Metal-Organic Framework-Based Orthogonal Nanoprobe for Recognition of Cellular Senescence

A luminescent nanoprobe capable of orthogonal sensing of two independent events is highly significant for unbiased disease-related detection such as the detection of senescent cells. Moreover, it is invaluable that the nanoprobe possesses a two-photon excitable characteristic that is highly suitable for imaging living cells and tissues. Herein, we present a two-photon-excitable multiluminescent orthogonal-sensing nanoprobe (OS nanoprobe) capable of detecting both pH elevation and β-galactosidase (β-gal) overexpression in senescent cells. In the design, Zr-based dual-emissive metal-organic frameworks prepared from two mixed amino linkers, referred to as NH2-MU, were used as the component for the ratiometric sensing of pH; additionally, fluorogenic resorufin-β-d-galactopyranoside, linked to the NH2-MU framework, enables β-gal detection. In the OS nanoprobe, the signals for pH and β-gal sensing remain independent while maintaining high colocalization. The two-photon excitable organic linkers of NH2-MU impart the OS nanoprobe with a bioimaging capability, allowing for the differentiation of senescent human foreskin fibroblast (HFF) cells from younger HFF cells or LacZ positive cells with the 800 nm laser excitation. This study marks the first instance of achieving the multiplexed orthogonal fluorescent sensing of cellular senescence using a two-photon excitation strategy, suggesting the potential of using versatile metal-organic framework (MOFs)-based fluorophores to realize the orthogonal multiplexing of disease-related biomarkers through multiphoton excitation.

Single-cell and spatial detection of senescent cells using DeepScence

Accurately identifying senescent cells is essential for studying their spatial and molecular features. We developed DeepScence, a method based on deep neural networks, to identify senescent cells in single-cell and spatial transcriptomics data. DeepScence is based on CoreScence, a senescence-associated gene set we curated that incorporates information from multiple published gene sets. We demonstrate that DeepScence can accurately identify senescent cells in single-cell gene expression data collected both in vitro and in vivo, as well as in spatial transcriptomics data generated by different platforms, substantially outperforming existing methods.

BMP2 and BMP7 cooperate with H3.3K27M to promote quiescence and invasiveness in pediatric diffuse midline gliomas

Pediatric diffuse midline gliomas (pDMG) are an aggressive type of childhood cancer with a fatal outcome. Their major epigenetic determinism has become clear, notably with the identification of K27M mutations in histone H3. However, the synergistic oncogenic mechanisms that induce and maintain tumor cell phenotype have yet to be deciphered. In 20 to 30% of cases, these tumors have an altered BMP signaling pathway with an oncogenic mutation on the BMP type I receptor ALK2, encoded by ACVR1. However, the potential impact of the BMP pathway in tumors non-mutated for ACVR1 is less clear. By integrating bulk, single-cell, and spatial transcriptomic data, we show here that the BMP signaling pathway is activated at similar levels between ACVR1 wild-type and mutant tumors and identify BMP2 and BMP7 as putative activators of the pathway in a specific subpopulation of cells. By using both pediatric isogenic glioma lines genetically modified to overexpress H3.3K27M and patients-derived DIPG cell lines, we demonstrate that BMP2/7 synergizes with H3.3K27M to induce a transcriptomic rewiring associated with a quiescent but invasive cell state. These data suggest a generic oncogenic role for the BMP pathway in gliomagenesis of pDMG and pave the way for specific targeting of downstream effectors mediating the K27M/BMP crosstalk.

Inhibition of mTOR prevents glucotoxicity-mediated increase of SA-beta-gal, p16INK4a, and insulin hypersecretion, without restoring electrical features of mouse pancreatic islets

An over-activation of the mechanistic target of rapamycin (mTOR) pathway promotes senescence and age-related diseases like type 2 diabetes. Besides, the regenerative potential of pancreatic islets deteriorates with aging. Nevertheless, the role of mTOR on senescence promoted by metabolic stress in islet cells as well as its relevance for electrophysiological aspects is not yet known. Here, we investigated whether parameters suggested to be indicative for senescence are induced in vitro in mouse islet cells by glucotoxicity and if mTOR inhibition plays a protective role against this. Islet cells exhibit a significant increase (~ 76%) in senescence-associated beta-galactosidase (SA-beta-gal) activity after exposure to glucotoxicity for 72 h. Glucotoxicity does not markedly influence p16INK4a protein within 72 h, but p16INK4a levels increase significantly after a 7-days incubation period. mTOR inhibition with a low rapamycin concentration (1 nM) entirely prevents the glucotoxicity-mediated increase of SA-beta-gal and p16INK4a. At the functional level, reactive oxygen species, calcium homeostasis, and electrical activity are disturbed by glucotoxicity, and rapamycin fails to prevent this. In contrast, rapamycin significantly attenuates the insulin hypersecretion promoted by glucotoxicity by modifying the mRNA levels of Vamp2 and Snap25 genes, related to insulin exocytosis. Our data indicate an influence of glucotoxicity on pancreatic islet-cell senescence and a reduction of the senescence markers by mTOR inhibition, which is relevant to preserve the regenerative potential of the islets. Decreasing the influence of mTOR on islet cells exposed to glucotoxicity attenuates insulin hypersecretion, but is not sufficient to prevent electrophysiological disturbances, indicating the involvement of mTOR-independent mechanisms.

Melatonin-loaded bioactive microspheres accelerate aged bone regeneration by formation of tunneling nanotubes to enhance mitochondrial transfer

The repair of bone defects in the elderly individuals is significantly delayed due to cellular senescence and dysfunction, which presents a challenge in clinical settings. Furthermore, there are limited effective methods available to promote bone repair in older individuals. Herein, melatonin-loaded mesoporous bioactive glasses microspheres (MTBG) were successfully prepared based on their mesoporous properties. The repair of bone defects in aged rats was significantly accelerated by enhancing mitochondrial function through the sustained release of melatonin and bioactive ions. MTBG effectively rejuvenated senescent bone marrow mesenchymal stem cells (BMSCs) by scavenging excessive reactive oxygen species (ROS), stabilizing the mitochondrial membrane potential (ΔΨm), and increasing ATP synthesis. Analysis of the underlying mechanism revealed that the formation of tunneling nanotubes (TNTs) facilitated the intercellular transfer of mitochondria, thereby resulting in the recovery of mitochondrial function. This study provides critical insights into the design of new biomaterials for the elderly individuals and the biological mechanism involved in aged bone regeneration.

The SASP factor IL-6 sustains cell-autonomous senescent cells via a cGAS-STING-NFκB intracrine senescent noncanonical pathway

Senescent cells produce a Senescence-Associated Secretory Phenotype (SASP) that involves factors with diverse and sometimes contradictory activities. One key SASP factor, interleukin-6 (IL-6), has the potential to amplify cellular senescence in the SASP-producing cells in an autocrine action, while simultaneously inducing proliferation in the neighboring cells. The underlying mechanisms for the contrasting actions remain unclear. We found that the senescence action does not involve IL-6 secretion nor the interaction with the receptor expressed in the membrane but is amplified through an intracrine mechanism. IL-6 sustains intracrine senescence interacting with the intracellular IL-6 receptor located in anterograde traffic specialized structures, with cytosolic DNA, cGAS-STING, and NFκB activation. This pathway triggered by intracellular IL-6 significantly contributes to cell-autonomous induction of senescence and impacts in tumor growth control. Inactivation of IL-6 in somatotrophic senescent cells transforms them into strongly tumorigenic in NOD/SCID mice, while re-expression of IL-6 restores senescence control of tumor growth. The intracrine senescent IL-6 pathway is further evidenced in three human cellular models of therapy-induced senescence. The compartmentalization of the intracellular signaling, in contrast to the paracrine tumorigenic action, provides a pathway for IL-6 to sustain cell-autonomous senescent cells, driving the SASP, and opens new avenues for clinical consideration to senescence-based therapies.

iPLA2β loss leads to age-related cognitive decline and neuroinflammation by disrupting neuronal mitophagy

BACKGROUND

During brain aging, disturbances in neuronal phospholipid metabolism result in impaired cognitive function and dysregulation of neurological processes. Mutations in iPLA2β are associated with neurodegenerative conditions that significantly impact brain phospholipids. iPLA2β deficiency exacerbates mitochondrial dysfunction and abnormal mitochondrial accumulation. We hypothesized that iPLA2β contributes to age-related cognitive decline by disrupting neuronal mitophagy.

METHODOLOGY

We used aged wild-type (WT) mice and iPLA2β-/- mice as natural aging models to assess cognitive performance, iPLA2β expression in the cortex, levels of chemokines and inflammatory cytokines, and mitochondrial dysfunction, with a specific focus on mitophagy and the mitochondrial phospholipid profile. To further elucidate the role of iPLA2β, we employed adeno-associated virus (AAV)-mediated iPLA2β overexpression in aged mice and re-evaluated these parameters.

RESULTS

Our findings revealed a significant reduction in iPLA2β levels in the prefrontal cortex of aged brains. Notably, iPLA2β-deficient mice exhibited impaired learning and memory. Loss of iPLA2β in the PFC of aged mice led to increased levels of chemokines and inflammatory cytokines. This damage was associated with altered mitochondrial morphology, reduced ATP levels due to dysregulation of the parkin-independent mitophagy pathway, and changes in the mitochondrial phospholipid profile. AAV-mediated overexpression of iPLA2β alleviated age-related parkin-independent mitophagy pathway dysregulation in primary neurons and the PFC of aged mice, reduced inflammation, and improved cognitive function.

CONCLUSIONS

Our study suggests that age-related iPLA2β loss in the PFC leads to cognitive decline through the disruption of mitophagy. These findings highlight the potential of targeting iPLA2β to ameliorate age-related neurocognitive disorders.

Human Multi-Lineage Liver Organoid Model Reveals Impairment of CYP3A4 Expression upon Repeated Exposure to Graphene Oxide

Three-dimensional hepatic cell cultures can provide an important advancement in the toxicity assessment of nanomaterials with respect to 2D models. Here, we describe liver organoids (LOs) obtained by assembling multiple cell lineages in a fixed ratio 1:1:0.2. These are upcyte® human hepatocytes, UHHs, upcyte® liver sinusoidal endothelial cells, LSECs, and human bone marrow-derived mesenchymal stromal cells, hbmMSCs. The structural and functional analyses indicated that LOs reached size stability upon ca. 10 days of cultivation (organoid maturation), showing a surface area of approximately 10 mm2 and the hepatic cellular lineages, UHHs and LSECs, arranged to form both primitive biliary networks and sinusoid structures, alike in vivo. LOs did not show signs of cellular apoptosis, senescence, or alteration of hepatocellular functions (e.g., dis-regulation of CYP3A4 or aberrant production of Albumin) for the entire culture period (19 days since organoid maturation). After that, LOs were repeatedly exposed for 19 days to a single or repeated dose of graphene oxide (GO: 2-40 µg/mL). We observed that the treatment did not induce any macroscopic signs of tissue damage, apoptosis activation, and alteration of cell viability. However, in the repeated dose regimen, we observed a down-regulation of CYP3A4 gene expression. Notably, these findings are in line with recent in vivo data, which report a similar impact on CYP3A4 when mice were repeatedly exposed to GO. Taken together, these findings warn of the potential detrimental effects of GO in real-life exposure (e.g., occupational scenario), where its progressive accumulation is likely expected. More in general, this study highlights that LOs formed by many cell lineages can enable repeated exposure regimens (suitable to mimic accumulation); thus, they can be suitably considered alternative or complementary in vitro systems to animal models.

Versatile and Efficient Protein Association Through Chemically Modified Sphingomyelin Nanosystems (SNs) for Enhanced Delivery

Proteins are biological macromolecules well known to regulate many cellular signaling mechanisms. For instance, they are very appealing for their application as therapeutic agents, presenting high specificity and activity. Nonetheless, they suffer from unfolding, instability and low bioavailability making their administration through systemic and other routes very tough. To overcome these drawbacks, drug delivery systems and nanotechnology have arisen to deliver biomolecules in a sustained manner while, at the same time, increasing dose availability, protecting the cargo without compromising proteins' bioactivity, and enhancing intracellular delivery. In this work, we proposed the optimization of sphingomyelin nanosystems (SNs) for the delivery of a wide collection of proteins (ranging from 10-500 kDa and pI) using diverse chemical association strategies. We have further characterized SNs by varied analytical methodologies. We have also carried out in vitro experiments to validate the potential of the developed formulations. As the final goal, we aim to obtain evidence of the potential use of SNs for the development of protein therapeutics.

Effector memory-type regulatory T cells display phenotypic and functional instability

Regulatory T cells (Treg cells) hold promise for sustainable therapy of immune disorders. Recent advancements in chimeric antigen receptor development and genome editing aim to enhance the specificity and function of Treg cells. However, impurities and functional instability pose challenges for the development of safe gene-edited Treg cell products. Here, we examined different Treg cell subsets regarding their fate, epigenomic stability, transcriptomes, T cell receptor repertoires, and function ex vivo and after manufacturing. Each Treg cell subset displayed distinct features, including lineage stability, epigenomics, surface markers, T cell receptor diversity, and transcriptomics. Earlier-differentiated memory Treg cell populations, including a hitherto unidentified naïve-like memory Treg cell subset, outperformed late-differentiated effector memory-like Treg cells in regulatory function, proliferative capacity, and epigenomic stability. High yields of stable, functional Treg cell products could be achieved by depleting the small effector memory-like Treg cell subset before manufacturing. Considering Treg cell subset composition appears critical to maintain lineage stability in the final cell product.

Histone chaperone HIRA, promyelocytic leukemia protein, and p62/SQSTM1 coordinate to regulate inflammation during cell senescence

Cellular senescence, a stress-induced stable proliferation arrest associated with an inflammatory senescence-associated secretory phenotype (SASP), is a cause of aging. In senescent cells, cytoplasmic chromatin fragments (CCFs) activate SASP via the anti-viral cGAS/STING pathway. Promyelocytic leukemia (PML) protein organizes PML nuclear bodies (NBs), which are also involved in senescence and anti-viral immunity. The HIRA histone H3.3 chaperone localizes to PML NBs in senescent cells. Here, we show that HIRA and PML are essential for SASP expression, tightly linked to HIRA's localization to PML NBs. Inactivation of HIRA does not directly block expression of nuclear factor κB (NF-κB) target genes. Instead, an H3.3-independent HIRA function activates SASP through a CCF-cGAS-STING-TBK1-NF-κB pathway. HIRA physically interacts with p62/SQSTM1, an autophagy regulator and negative SASP regulator. HIRA and p62 co-localize in PML NBs, linked to their antagonistic regulation of SASP, with PML NBs controlling their spatial configuration. These results outline a role for HIRA and PML in the regulation of SASP.

A nutrigeroscience approach: Dietary macronutrients and cellular senescence

Cellular senescence, a process in which a cell exits the cell cycle in response to stressors, is one of the hallmarks of aging. Senescence and the senescence-associated secretory phenotype (SASP)-a heterogeneous set of secreted factors that disrupt tissue homeostasis and promote the accumulation of senescent cells-reprogram metabolism and can lead to metabolic dysfunction. Dietary interventions have long been studied as methods to combat age-associated metabolic dysfunction, promote health, and increase lifespan. A growing body of literature suggests that senescence is responsive to diet, both to calories and specific dietary macronutrients, and that the metabolic benefits of dietary interventions may arise in part through reducing senescence. Here, we review what is currently known about dietary macronutrients' effect on senescence and the SASP, the nutrient-responsive molecular mechanisms that may mediate these effects, and the potential for these findings to inform the development of a nutrigeroscience approach to healthy aging.

Brief guide to senescence assays using cultured mammalian cells

Cellular senescence is a crucial biological process associated with organismal aging and many chronic diseases. Here, we present a brief guide to mammalian senescence assays, including the measurement of cell cycle arrest, change in cellular morphology, senescence-associated β-galactosidase (SA-β-gal) staining, and the expression of senescence-associated secretory phenotype (SASP). This work will be useful for biologists with minimum expertise in cellular senescence assays.

Long-term demyelination and aging-associated changes in mice corpus callosum; evidence for the role of accelerated aging in remyelination failure in a mouse model of multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory and demyelinating disorder affecting the central nervous system. Evidence suggests that age-related neurodegeneration contributes to disability progression during the chronic stages of MS. Aging is characterized by decreased regeneration potential and impaired myelin repair in the brain. It is hypothesized that accelerated cellular aging contributes to the functional decline associated with neurodegenerative diseases. We assessed the impact of aging on myelin content in the corpus callosum (CC) and compared aging with the long-term demyelination (LTD) consequents induced by 12 weeks of feeding with a cuprizone (CPZ) diet. Initially, evaluating myelin content in 2-, 6-, and 18-month-old mice revealed a reduction in myelin content, particularly at 18 months. Myelin thickness was decreased and the g-ratio increased in aged mice. Although a lower myelin content and higher g-ratio were observed in LTD model mice, compared to the normally aged mice, both aging and LTD exhibited relatively similar myelin ultrastructure. Our findings provide evidence that LTD exhibits the hallmarks of aging such as elevated expression of senescence-associated genes, mitochondrial dysfunction, and high level of oxidative stress as observed following normal aging. We also investigated the senescence-associated β-galactosidase activity in O4+ late oligodendrocyte progenitor cells (OPCs). The senescent O4+/β-galactosidase+ cells were elevated in the CPZ diet. Our data showed that the myelin degeneration in CC occurs throughout the lifespan, and LTD induced by CPZ accelerates the aging process which may explain the impairment of myelin repair in patients with progressive MS.