EA.hy926 Cells and HUVECs Share Similar Senescence Phenotypes but Respond Differently to the Senolytic Drug ABT-263

An Antibody-directed and Immune Response Modifier-augmented Photothermal Therapy Strategy Relieves Aging via Rapid Immune Clearance of Senescent Cells

Cellular senescence is an irreversible and multifaceted process inducing tissue dysfunction and organismal aging, and thus the clearance of senescent cells can prevent or delay the onset of aging-related pathologies. Herein, we developed an augmented photothermal therapy strategy integrated with an antibody against β2-microglobulin (aB2MG) and an immune adjuvant imiquimod (R837) to effectively accelerate senescent cell apoptosis and clearance under a near-infrared light. With this strategy, the designed CroR@aB2MG enables the targeting of senescent cells and the application of photothermal therapy concomitantly, the initiation of immune clearance subsequently, and finally the realization of protective effects against senescence. Our results showed that the photo-induced heating effect caused senescent cells to quickly undergo apoptosis and the synchronous immune response accelerated the clearance of senescent cells in vitro and in vivo. Therefore, this photoactivated speedy clearing strategy may provide an efficient way for the treatment of senescence-related diseases by eliminating senescent cells with biomaterials.

Carbon Nanodots Inhibit Tumor Necrosis Factor-α-Induced Endothelial Inflammation through Scavenging Hydrogen Peroxide and Upregulating Antioxidant Gene Expression in EA.hy926 Endothelial Cells

Carbon nanodots (CNDs) are a new type of nanomaterial with a size of less than 10 nanometers and excellent biocompatibility, widely used in fields such as biological imaging, transmission, diagnosis, and drug delivery. However, its potential and mechanism to mediate endothelial inflammation have yet to be explored. Here, we report that the uptake of CNDs by EA.hy926 endothelial cells is both time and dose dependent. The concentration of CNDs used in this experiment was found to not affect cell viability. TNF-α is a known biomarker of vascular inflammation. Cells treated with CNDs for 24 h significantly inhibited TNF-α (0.5 ng/mL)-induced expression of intracellular adhesion molecule 1 (ICAM-1) and interleukin 8 (IL-8). ICAM-1 and IL-8 are two key molecules responsible for the activation and the firm adhesion of monocytes to activated endothelial cells for the initiation of atherosclerosis. ROS, such as hydrogen peroxide, play an important role in TNF-α-induced inflammation. Interestingly, we found that CNDs effectively scavenged H2O2 in a dose-dependent manner. CNDs treatment also increased the activity of the antioxidant enzyme NQO1 in EA.hy926 endothelial cells indicating the antioxidant properties of CNDs. These results suggest that the anti-inflammatory effects of CNDs may be due to the direct H2O2 scavenging properties of CNDs and the indirect upregulation of antioxidant enzyme NQO1 activity in endothelial cells. In conclusion, CND can inhibit TNF-α-induced endothelial inflammation, possibly due to its direct scavenging of H2O2 and the indirect upregulation of antioxidant enzyme NQO1 activity in endothelial cells.

Researching New Drug Combinations with Senolytic Activity Using Senescent Human Lung Fibroblasts MRC-5 Cell Line

Therapeutically targeting senescent cells seems to be an interesting perspective in treating chronic lung diseases, which are often associated with human aging. The combination of the drug dasatinib and the polyphenol quercetin is used in clinical trials as a senolytic, and the first results point to the relief of physical dysfunction in patients with idiopathic pulmonary fibrosis. In this work, we tested new combinations of drugs and polyphenols, looking for senolytic activity using human lung fibroblasts (MRC-5 cell line) with induced senescence. We researched drugs, such as azithromycin, rapamycin, metformin, FK-506, aspirin, and dasatinib combined with nine natural polyphenols, namely caffeic acid, chlorogenic acid, ellagic acid, ferulic acid, gallic acid, epicatechin, hesperidin, quercetin, and resveratrol. We found new effective senolytic combinations with dasatinib and ellagic acid and dasatinib and resveratrol. Both drug combinations increased apoptosis, reduced BCL-2 expression, and increased caspase activity in senescent MRC-5 cells. Ellagic acid senolytic activity was more potent than quercetin, and resveratrol counteracted inflammatory cytokine release during senolysis in vitro. In conclusion, dasatinib and ellagic acid and dasatinib and resveratrol present in vitro senolytic potential like that observed for the combination in clinical trials of dasatinib and quercetin, and maybe they could be future alternatives in the senotherapeutic field.

Size-Dependent Polymeric Nanoparticle Distribution in a Static versus Dynamic Microfluidic Blood Vessel Model: Implications for Nanoparticle-Based Drug Delivery

Nanoparticles (NPs) have been widely investigated in the nanomedicine field. One of the main challenges is to accurately predict the NP distribution and fate after administration. Microfluidic platforms acquired huge importance as tools to model the in vivo environment. In this study, we leveraged a microfluidic platform to produce FITC-labeled poly(lactide-co-glycolide)-block-poly(ethylene glycol) (PLGA-PEG) NPs with defined sizes of 30, 50, and 70 nm. The study aimed to compare the ability of NPs with differences of 20 nm in size to cross an endothelial barrier using static (Transwell inserts) and dynamic (microfluidic perfusion device) in vitro models. Our results evidence a size-dependent NP crossing in both models (30 > 50 > 70 nm) and highlight the bias deriving from the static model, which does not involve shear stresses. The permeation of each NP size was significantly higher in the static system than in the dynamic model at the earliest stages. However, it gradually decreased to levels comparable with those of the dynamic model. Overall, this work highlights clear differences in NP distribution over time in static versus dynamic conditions and distinct size-dependent patterns. These findings reinforce the need for accurate in vitro screening models that allow for more accurate predictions of in vivo performance.

Metformin mitigates SASP secretion and LPS-triggered hyper-inflammation in Doxorubicin-induced senescent endothelial cells

Introduction: Doxorubicin (DOX), a chemotherapeutic drug, induces senescence and increases the secretion of senescence-associated secretory phenotype (SASP) in endothelial cells (ECs), which contributes to DOX-induced inflammaging. Metformin, an anti-diabetic drug, demonstrates senomorphic effects on different models of senescence. However, the effects of metformin on DOX-induced endothelial senescence have not been reported before. Senescent ECs exhibit a hyper-inflammatory response to lipopolysachharide (LPS). Therefore, in our current work, we identified the effects of metformin on DOX-induced endothelial senescence and LPS-induced hyper-inflammation in senescent ECs. Methods: ECs were treated with DOX ± metformin for 24 h followed by 72 h incubation without DOX to establish senescence. Effects of metformin on senescence markers expression, SA-β-gal activity, and SASP secretion were assessed. To delineate the molecular mechanisms, the effects of metformin on major signaling pathways were determined. The effect of LPS ± metformin was determined by stimulating both senescent and non-senescent ECs with LPS for an additional 24 h. Results: Metformin corrected DOX-induced upregulation of senescence markers and decreased the secretion of SASP factors and adhesion molecules. These effects were associated with a significant inhibition of the JNK and NF-κB pathway. A significant hyper-inflammatory response to LPS was observed in DOX-induced senescent ECs compared to non-senescent ECs. Metformin blunted LPS-induced upregulation of pro-inflammatory SASP factors. Conclusion: Our study demonstrates that metformin mitigates DOX-induced endothelial senescence phenotype and ameliorates the hyper-inflammatory response to LPS. These findings suggest that metformin may protect against DOX-induced vascular aging and endothelial dysfunction and ameliorate infection-induced hyper-inflammation in DOX-treated cancer survivors.

The Potential of Senescence as a Target for Developing Anticancer Therapy

Senescence occurs in response to various stimuli. Senescence has attracted attention because of its potential use in anticancer therapy as it plays a tumor-suppressive role. It also promotes tumorigeneses and therapeutic resistance. Since senescence can induce therapeutic resistance, targeting senescence may help to overcome therapeutic resistance. This review provides the mechanisms of senescence induction and the roles of the senescence-associated secretory phenotype (SASP) in various life processes, including therapeutic resistance and tumorigenesis. The SASP exerts pro-tumorigenic or antitumorigenic effects in a context-dependent manner. This review also discusses the roles of autophagy, histone deacetylases (HDACs), and microRNAs in senescence. Many reports have suggested that targeting HDACs or miRNAs could induce senescence, which, in turn, could enhance the effects of current anticancer drugs. This review presents the view that senescence induction is a powerful method of inhibiting cancer cell proliferation.

Inhibition of glutaminolysis restores mitochondrial function in senescent stem cells

Mitochondrial dysfunction, a hallmark of aging, has been associated with the onset of aging phenotypes and age-related diseases. Here, we report that impaired mitochondrial function is associated with increased glutamine catabolism in senescent human mesenchymal stem cells (MSCs) and myofibroblasts derived from patients suffering from Hutchinson-Gilford progeria syndrome. Increased glutaminase (GLS1) activity accompanied by loss of urea transporter SLC14A1 induces urea accumulation, mitochondrial dysfunction, and DNA damage. Conversely, blocking GLS1 activity restores mitochondrial function and leads to amelioration of aging hallmarks. Interestingly, GLS1 expression is regulated through the JNK pathway, as demonstrated by chemical and genetic inhibition. In agreement with our in vitro findings, tissues isolated from aged or progeria mice display increased urea accumulation and GLS1 activity, concomitant with declined mitochondrial function. Inhibition of glutaminolysis in progeria mice improves mitochondrial respiratory chain activity, suggesting that targeting glutaminolysis may be a promising strategy for restoring age-associated loss of mitochondrial function.

Anthracycline-induced cardiotoxicity and senescence

Cancer continues to place a heavy burden on healthcare systems around the world. Although cancer survivorship continues to improve, cardiotoxicity leading to cardiomyopathy and heart failure as a consequence of cancer therapy is rising, and yesterday's cancer survivors are fast becoming today's heart failure patients. Although the mechanisms driving cardiotoxicity are complex, cellular senescence is gaining attention as a major contributor to chemotherapy-induced cardiotoxicity and, therefore, may also represent a novel therapeutic target to prevent this disease. Cellular senescence is a well-recognized response to clinical doses of chemotherapies, including anthracyclines, and is defined by cell cycle exit, phenotypic alterations which include mitochondrial dysfunction, and the expression of the pro-senescent, pro-fibrotic, and pro-inflammatory senescence-associated phenotype. Senescence has an established involvement in promoting myocardial remodeling during aging, and studies have demonstrated that the elimination of senescence can attenuate the pathophysiology of several cardiovascular diseases. Most recently, pharmacology-mediated elimination of senescence, using a class of drugs termed senolytics, has been demonstrated to prevent myocardial dysfunction in preclinical models of chemotherapy-induced cardiotoxicity. In this review, we will discuss the evidence that anthracycline-induced senescence causes the long-term cardiotoxicity of anticancer chemotherapies, consider how the senescent phenotype may promote myocardial dysfunction, and examine the exciting possibility that targeting senescence may prove a therapeutic strategy to prevent or even reverse chemotherapy-induced cardiac dysfunction.