The Achilles' heel of senescent cells: from transcriptome to senolytic drugs

The functional role of cellular senescence during vascular calcification in chronic kidney disease

Vascular calcification (VC) has emerged as a key predictor of cardiovascular events in patients with chronic kidney disease (CKD). In recent years, an expanding body of research has put forth the concept of accelerated vascular aging among CKD patients, highlighting the significance of vascular cells senescence in the process of VC. Within the milieu of uremia, senescent vascular endothelial cells (VECs) release extracellular microvesicles (MV) that promote vascular smooth muscle cells (VSMCs) senescence, thereby triggering the subsequent osteogenic phenotypic switch and ultimately contributing to the VC process. In addition, senescent vascular progenitor or stem cells with diminished ability to differentiate into VECs and VSMCS, compromise the repair of vascular integrity, on the other hand, release a cascade of molecules associated with senescence, collectively known as the senescence-associated secretory phenotype (SASP), perpetuating the senescence phenomenon. Furthermore, SASP triggers the recruitment of monocytes and macrophages, as well as adjacent VECs and VSMCs into a pro-adhesive and pro-inflammatory senescent state. This pro-inflammatory microenvironment niche not only impacts the functionality of immune cells but also influences the differentiation of myeloid immune cells, thereby amplifying the reduced ability to effectively clear senescent cells of senescent macrophages, promoted calcification of VSMCs. The objective of this paper is to provide a comprehensive review of the contribution of vascular cell senescence to the emergence and advancement of VC. Gaining a comprehensive understanding of the involvement of cellular senescence within the vessel wall is pivotal, especially when it comes to its intersection with VC. This knowledge is essential for advancing groundbreaking anti-aging therapies, aiming to effectively mitigate cardiovascular diseases.

Aging and atrial fibrillation: A vicious circle

Atrial fibrillation (AF) is the commonest sustained cardiac arrhythmia observed in clinical practice. Its prevalence increases dramatically with advancing age. This review article discusses the recent advances in studies investigating the relationship between aging and AF and the possible underlying mechanisms.

The significance of caloric restriction mimetics as anti-aging drugs

Aging is an intricate process characterized by the gradual deterioration of the physiological integrity of a living organism. This unfortunate phenomenon inevitably leads to a decline in functionality and a heightened susceptibility to the ultimate fate of mortality. Therefore, it is of utmost importance to implement interventions that possess the capability to reverse or preempt age-related pathology. Caloric restriction mimetics (CRMs) refer to a class of molecules that have been observed to elicit advantageous outcomes on both health and longevity in various model organisms and human subjects. Notably, these compounds offer a promising alternative to the arduous task of adhering to a caloric restriction diet and mitigate the progression of the aging process and extend the duration of life in laboratory animals and human population. A plethora of molecular signals have been linked to the practice of caloric restriction, encompassing Insulin-like Growth Factor 1 (IGF1), Mammalian Target of Rapamycin (mTOR), the Adenosine Monophosphate-Activated Protein Kinase (AMPK) pathway, and Sirtuins, with particular emphasis on SIRT1. Therefore, this review will center its focus on several compounds that act as CRMs, highlighting their molecular targets, chemical structures, and mechanisms of action. Moreover, this review serves to underscore the significant relationship between post COVID-19 syndrome, antiaging, and importance of utilizing CRMs. This particular endeavor will serve as a comprehensive guide for medicinal chemists and other esteemed researchers, enabling them to meticulously conceive and cultivate novel molecular entities with the potential to function as efficacious antiaging pharmaceutical agents.

Pharmacological Targeting of Senescence with Senolytics as a New Therapeutic Strategy for Neurodegeneration

Cellular senescence is a state of permanent cell-cycle arrest. Early in life, senescence has a physiologic role in tumor suppression and wound healing. However, gradually, as these senescent cells accumulate over the lifespan of an organism, they contribute to inflammation and the progression of age-related diseases, including neurodegeneration. Targeting senescent cells using a class of drugs known as "senolytics" holds great promise for the management of Alzheimer's and Parkinson's disease. Already, several senolytic compounds have been shown to ameliorate cognitive deficits across several preclinical models of neurodegeneration. Most of these senolytics (e.g., dasatinib) are repurposed clinical or experimental anticancer drugs, which trigger apoptosis of senescent cells by interfering with pro-survival pathways. However, outside of their senolytic function, many first-generation senolytics also have other less appreciated neuroprotective effects, such as potent antioxidant and anti-inflammatory activity. In addition, some senolytic drugs may also have negative dose-limiting toxicities, including thrombocytopenia. In this review, we discuss the various biologic pathways targeted by the leading senolytic drugs, namely dasatinib, quercetin, fisetin, and navitoclax. We further evaluate the clinical transability of these compounds for neurodegeneration, assessing their adverse effects, pharmacokinetic properties, and chemical structure. SIGNIFICANCE STATEMENT: Currently, there are no effective disease-modifying treatments for the most prevalent neurodegenerative disorders, including Alzheimer's and Parkinson's disease. Some of the drugs currently available for treating these diseases are associated with unwanted side-effects and/or become less efficacious with time. Therefore, researchers have begun to explore new innovative treatments for these belligerent diseases, including senolytic drugs. These agents lead to the apoptosis of senescent cells thereby preventing their deleterious role in neurodegeneration.

Mitofusin 1 silencing decreases the senescent associated secretory phenotype, promotes immune cell recruitment and delays melanoma tumor growth after chemotherapy

Cellular senescence is a therapy endpoint in melanoma, and the senescence-associated secretory phenotype (SASP) can affect tumor growth and microenvironment, influencing treatment outcomes. Metabolic interventions can modulate the SASP, and mitochondrial energy metabolism supports resistance to therapy in melanoma. In a previous report we showed that senescence, induced by the DNA methylating agent temozolomide, increased the level of fusion proteins mitofusin 1 and 2 in melanoma, and silencing Mfn1 or Mfn2 expression reduced interleukin-6 secretion by senescent cells. Here we expanded these observations evaluating the secretome of senescent melanoma cells using shotgun proteomics, and explored the impact of silencing Mfn1 on the SASP. A significant increase in proteins reported to reduce the immune response towards the tumor was found in the media of senescent cells. The secretion of several of these immunomodulatory proteins was affected by Mfn1 silencing, among them was galectin-9. In agreement, tumors lacking mitofusin 1 responded better to treatment with the methylating agent dacarbazine, tumor size was reduced and a higher immune cell infiltration was detected in the tumor. Our results highlight mitochondrial dynamic proteins as potential pharmacological targets to modulate the SASP in the context of melanoma treatment.

Modulation of fracture healing by senescence-associated secretory phenotype (SASP): a narrative review of the current literature

The senescence-associated secretory phenotype (SASP) is a generic term for the secretion of cytokines, such as pro-inflammatory factors and proteases. It is a crucial feature of senescent cells. SASP factors induce tissue remodeling and immune cell recruitment. Previous studies have focused on the beneficial role of SASP during embryonic development, wound healing, tissue healing in general, immunoregulation properties, and cancer. However, some recent studies have identified several negative effects of SASP on fracture healing. Senolytics is a drug that selectively eliminates senescent cells. Senolytics can inhibit the function of senescent cells and SASP, which has been found to have positive effects on a variety of aging-related diseases. At the same time, recent data suggest that removing senescent cells may promote fracture healing. Here, we reviewed the latest research progress about SASP and illustrated the inflammatory response and the influence of SASP on fracture healing. This review aims to understand the role of SASP in fracture healing, aiming to provide an important clinical prevention and treatment strategy for fracture. Clinical trials of some senolytics agents are underway and are expected to clarify the effectiveness of their targeted therapy in the clinic in the future. Meanwhile, the adverse effects of this treatment method still need further study.

Targeting therapy-induced senescence as a novel strategy to combat chemotherapy-induced peripheral neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is a treatment-limiting adverse effect of anticancer therapy that complicates the lifestyle of many cancer survivors. There is currently no gold-standard for the assessment or management of CIPN. Subsequently, understanding the underlying mechanisms that lead to the development of CIPN is essential for finding better pharmacological therapy. Therapy-induced senescence (TIS) is a form of senescence that is triggered in malignant and non-malignant cells in response to the exposure to chemotherapy. Recent evidence has also suggested that TIS develops in the dorsal root ganglia of rodent models of CIPN. Interestingly, several components of the senescent phenotype are commensurate with the currently established primary processes implicated in the pathogenesis of CIPN including mitochondrial dysfunction, oxidative stress, and neuroinflammation. In this article, we review the literature that supports the hypothesis that TIS could serve as a holistic mechanism leading to CIPN, and we propose the potential for investigating senotherapeutics as means to mitigate CIPN in cancer survivors.

Eternal Youth: A Comprehensive Exploration of Gene, Cellular, and Pharmacological Anti-Aging Strategies

The improvement of human living conditions has led to an increase in average life expectancy, creating a new social and medical problem-aging, which diminishes the overall quality of human life. The aging process of the body begins with the activation of effector signaling pathways of aging in cells, resulting in the loss of their normal functions and deleterious effects on the microenvironment. This, in turn, leads to chronic inflammation and similar transformations in neighboring cells. The cumulative retention of these senescent cells over a prolonged period results in the deterioration of tissues and organs, ultimately leading to a reduced quality of life and an elevated risk of mortality. Among the most promising methods for addressing aging and age-related illnesses are pharmacological, genetic, and cellular therapies. Elevating the activity of aging-suppressing genes, employing specific groups of native and genetically modified cells, and utilizing senolytic medications may offer the potential to delay aging and age-related ailments over the long term. This review explores strategies and advancements in the field of anti-aging therapies currently under investigation, with a particular emphasis on gene therapy involving adeno-associated vectors and cell-based therapeutic approaches.

Biochemical and transcriptomic evaluation of a 3D lung organoid platform for pre-clinical testing of active substances targeting senescence

Chronic lung diseases such as chronic obstructive pulmonary disease and cystic fibrosis are incurable. Epithelial senescence, a state of dysfunctional cell cycle arrest, contributes to the progression of such diseases. Therefore, lung epithelial cells are a valuable target for therapeutic intervention. Here, we present a 3D airway lung organoid platform for the preclinical testing of active substances with regard to senescence, toxicity, and inflammation under standardized conditions in a 96 well format. Senescence was induced with doxorubicin and measured by activity of senescence associated galactosidase. Pharmaceutical compounds such as quercetin antagonized doxorubicin-induced senescence without compromising organoid integrity. Using single cell sequencing, we identified a subset of cells expressing senescence markers which was decreased by quercetin. Doxorubicin induced the expression of detoxification factors specifically in goblet cells independent of quercetin. In conclusion, our platform enables for the analysis of senescence-related processes and will allow the pre-selection of a wide range of compounds (e.g. natural products) in preclinical studies, thus reducing the need for animal testing.

Recent Advancement in Elimination Strategies and Potential Rejuvenation Targets of Senescence

Cellular senescence is a state of exiting the cell cycle, resisting apoptosis, and changing phenotype. Senescent cells (SCs) can be identified by large, distorted morphology and irreversible inability to replicate. In early development, senescence has beneficial roles like tissue patterning and wound healing, where SCs are cleared by the immune system. However, there is a steep rise in SC number as organisms age. The issue with SC accumulation stems from the loss of cellular function, alterations of the microenvironment, and secretions of pro-inflammatory molecules, consisting of cytokines, chemokines, matrix metalloproteinases (MMPs), interleukins, and extracellular matrix (ECM)-associated molecules. This secreted cocktail is referred to as the senescence-associated secretory phenotype (SASP), a hallmark of cellular senescence. The SASP promotes inflammation and displays a bystander effect where paracrine signaling turns proliferating cells into senescent states. To alleviate age-associated diseases, researchers have developed novel methods and techniques to selectively eliminate SCs in aged individuals. Although studies demonstrated that selectively killing SCs improves age-related disorders, there are drawbacks to SC removal. Considering favorable aspects of senescence in the body, this paper reviews recent advancements in elimination strategies and potential rejuvenation targets of senescence to bring researchers in the field up to date.

Model organism life extending therapeutics modulate diverse nodes in the drug-gene-microbe tripartite human longevity interactome

Advances in antiaging drug/lead discovery in animal models constitute a large body of literature on novel senotherapeutics and geroprotectives. However, with little direct evidence or mechanism of action in humans-these drugs are utilized as nutraceuticals or repurposed supplements without proper testing directions, appropriate biomarkers, or consistent in-vivo models. In this study, we take previously identified drug candidates that have significant evidence of prolonging lifespan and promoting healthy aging in model organisms, and simulate them in human metabolic interactome networks. Screening for drug-likeness, toxicity, and KEGG network correlation scores, we generated a library of 285 safe and bioavailable compounds. We interrogated this library to present computational modeling-derived estimations of a tripartite interaction map of animal geroprotective compounds in the human molecular interactome extracted from longevity, senescence, and dietary restriction-associated genes. Our findings reflect previous studies in aging-associated metabolic disorders, and predict 25 best-connected drug interactors including Resveratrol, EGCG, Metformin, Trichostatin A, Caffeic Acid and Quercetin as direct modulators of lifespan and healthspan-associated pathways. We further clustered these compounds and the functionally enriched subnetworks therewith to identify longevity-exclusive, senescence-exclusive, pseudo-omniregulators and omniregulators within the set of interactome hub genes. Additionally, serum markers for drug-interactions, and interactions with potentially geroprotective gut microbial species distinguish the current study and present a holistic depiction of optimum gut microbial alteration by candidate drugs. These findings provide a systems level model of animal life-extending therapeutics in human systems, and act as precursors for expediting the ongoing global effort to find effective antiaging pharmacological interventions.Communicated by Ramaswamy H. Sarma.

Immunosenescence and Inflamm-Aging: Clinical Interventions and the Potential for Reversal of Aging

Inflammation is often associated with the impairment of the ability to sustain the consequences of the physical, chemical, nutritional, and antigenic triggers of inflammation. The process of immunosenescence may only partially be explained by the senescence of cells, tissues, or the organism, and, hence, the hallmarks of immunosenescence may be markedly and differentially affected by the history of an individual's pathogenic encounter. Inflammation is a key component of immunosenescence, which itself is a direct consequence of aging. This review article highlights the therapeutic interventions for slowing the processes of inflamm-aging and immunosenescence and the possible reversal of aging and includes domains of immunomodulatory interventions, vaccination strategies, nutritional interventions, stem cell therapies, personalized medicine, microbiome interventions, and the positive effects of physical activity and exercise.

Editorial Commentary: Dasatinib With Quercetin Shows Promise in Decreasing Age-Related Senescence in the Rotator Cuff Tendon-Can It Work Elsewhere?

Cellular senescence is a fundamental mechanism seen in all age-related diseases. Human supraspinatus tendon and adjacent bursal specimens evaluated for cellular senescence by immunohistochemistry and gene expression show more senescent cells in older patients. This confirms the observation that older patients are more likely to have rotator cuff pathology, and older age is associated with lower rates of rotator cuff healing and more frequent tendon retears. Senolytic drugs can selectively eliminate senescent cells without a localized or systemic impact. Tendon and bursal specimens co-cultured and then incubated with dasatinib and quercetin for 48 hours show a significant decrease in senescent cells. This suggests that these drugs may slow biological aging in rotator cuff tendons and offer the possibility of a clinically effective treatment for the aging rotator cuff tendon. Moreover, this concept is promising for the development of future effective therapies addressing tissue senescence.

Immunologic landscape of human hepatic hemangiomas and epithelioid hemangioendotheliomas

BACKGROUND

The missing requirement for resection for the majority of hepatic hemangiomas (HH) and tissue scarcity for rare diseases such as hepatic epithelioid hemangioendotheliomas (HEHE) complicate the characterization of the spatial immunovascular niche of these benign and malignant vascular neoplastic diseases.

METHODS

Two tissue cohorts containing 98 HHs and 13 HEHEs were used to study entity-specific and disease stage-specific endothelial cell (EC) phenotype and immune cell abundance. Using semiquantitative assessment, annotation-based cell classifiers, digital cell detection on whole slides, and tissue microarrays, we quantified 23 immunologic and vascular niche-associated markers and correlated this with clinicopathologic data.

RESULTS

Both HH and HEHE ECs were characterized by a CD31high, CD34high, FVIII-related antigenhigh expression phenotype with entity-specific expression differences of sinusoidal EC markers Stabilin1, Stabilin2, CD32, and Lymphatic Vessel Endothelial Hyaluronan Receptor 1 (LYVE-1). Cell detection identified an HH margin-prevailing immunologic response dominated by Myeloperoxidase+ (MPO+) macrophages, CD3+ and CD8+ T cell subsets, and B cells (CD20+, CD79A+). In HEHE, increased CD68+ and CD20+ cell demarcation of lesion margins was observed, while CD3+ and CD8+ T cells were equally detectable both marginally and intralesionally. Stage-specific pairwise correlation analysis of HH and HEHE revealed disease entity-specific immunologic infiltration patterns as seen by high CD117+ cell numbers in HH, while HEHE samples showed increased CD3+ T cell infiltration.

CONCLUSIONS

ECs in HH and HEHE share a continuous EC expression phenotype, while the expression of sinusoidal EC markers is more highly retained in HEHE. These phenotypic differences are associated with a unique and disease-specific immunovascular landscape.

A Need for Refined Senescence Biomarkers and Measures of Senolytics in the Brain

Cellular senescence contributes to Alzheimer's disease (AD) pathogenesis. Treatments that remove senescent cells, senolytics, improve brain outcomes in AD mice with amyloid-β or tau deposition. 3xTgAD mice develop both AD neuropathologies; however, Ng et al. report low p16INK4a-associated senescence in the brain. Senolytic treatment by genetic removal; dasatinib with quercetin (D+Q), which enter the brain; and ABT-263 with limited brain penetrance all reduced AD neuropathology. Refined measures of senescence and brain exposure would help clarify the benefits of senolytics despite low p16INK4a-associated senescence and potential limited brain penetrance.

Delaying Brain Aging or Decreasing Tau Levels as Strategies to Prevent Alzheimer's Disease: In Memoriam of Mark A. Smith

Aging is the main risk for neurodegenerative disorders like Alzheimer's disease. In this short review, I will comment on how delaying brain aging through the addition of Yamanaka Factors or small compounds that bind to the folate receptor alpha, which promote the expression of the Yamanaka Factors or by the decrease tau levels in brain cells from older subjects could serve as strategies to prevent Alzheimer's disease.

The biological mechanism and emerging therapeutic interventions of liver aging

Research on liver aging has become prominent and has attracted considerable interest in uncovering the mechanism and therapeutic targets of aging to expand lifespan. In addition, multi-omics studies are widely used to perform further mechanistic investigations on liver aging. In this review, we illustrate the changes that occur with aging in the liver, present the current models of liver aging, and emphasize existing multi-omics studies on liver aging. We integrated the multi-omics data of enrolled studies and reanalyzed them to identify key pathways and targets of liver aging. The results indicated that C-X-C motif chemokine ligand 9 (Cxcl9) was a regulator of liver aging. In addition, we provide a flowchart for liver aging research using multi-omics analysis and molecular experiments to help researchers conduct further research. Finally, we present emerging therapeutic treatments that prolong lifespan. In summary, using cells and animal models of liver aging, we can apply a multi-omics approach to find key metabolic pathways and target genes to mitigate the adverse effects of liver aging.

Senescent adipocytes and type 2 diabetes - current knowledge and perspective concepts

Among civilization diseases, the number of individuals suffering from type 2 diabetes (T2DM) is expected to increase to more than a billion in less than 20 years, which is associated with, e.g., populational aging, poor diet, sedentary lifestyle, genetic predispositions, and immunological factors. T2DM affects many organs and is characterized by insulin resistance, high glucose levels, and adipocyte dysfunction, which are related to senescence. Although this type of cellular aging has beneficial biological functions, it can also act unfavorable since senescent adipocytes resist apoptosis, enhance cytokine secretion, downregulate cell identity genes, and acquire the senescence-associated secretory phenotype that renders a more oxidative environment. Opposing T2DM is possible via a wide variety of senotherapies, including senolytics and senomorphics; nevertheless, further research is advised to expand therapeutic possibilities and benefits. Consequences that ought to be deeply researched include secretory phenotype, chronic inflammation, increasing insulin resistance, as well as impairment of adipogenesis and functioning of adipocyte cells. Herein, despite reviewing T2DM and fat tissue senescence, we summarized the latest adipocyte-related anti-diabetes solutions and suggested further research directions.

Human Rotator Cuff Tears Reveal an Age-Dependent Increase in Markers of Cellular Senescence and Selective Removal of Senescent Cells With Dasatinib + Quercetin Increases Genetic Expression of COL1A1 In Vitro

PURPOSE

To quantify cellular senescence in supraspinatus tendon and subacromial bursa of humans with rotator cuff tears and to investigate the in vitro efficacy of the senolytic dasatinib + quercetin (D+Q) to eliminate senescent cells and alter tenogenic differentiation.

METHODS

Tissue was harvested from 41 patients (mean age, 62 years) undergoing arthroscopic rotator cuff repairs. In part 1 (n = 35), senescence was quantified using immunohistochemistry and gene expression for senescent cell markers (p16 and p21) and the senescence-associated secretory phenotype (SASP) (interleukin [IL] 6, IL-8, matrix metalloproteinase [MMP] 3, monocyte chemoattractant protein [MCP] 1). Senescence was compared between patients <60 and ≥60 years old. In part 2 (n = 6) , an in vitro model of rotator cuff tears was treated with D+Q or control. D+Q, a chemotherapeutic and plant flavanol, respectively, kill senescent cells. Gene expression analysis assessed the ability of D+Q to kill senescent cells and alter markers of tenogenic differentiation.

RESULTS

Part 1 revealed an age-dependent significant increase in the relative expression of p21, IL-6, and IL-8 in tendon and p21, p16, IL-6, IL-8, and MMP-3 in bursa (P < .05). A significant increase was seen in immunohistochemical staining of bursa p21 (P = .028). In part 2, D+Q significantly decreased expression of p21, IL-6, and IL-8 in tendon and p21 and IL-8 in bursa (P < .05). Enzyme-linked immunosorbent assay analysis showed decreased release of the SASP (IL-6, MMP-3, MCP-1; P = .002, P = .024, P < .001, respectively). Tendon (P = .022) and bursa (P = .027) treated with D+Q increased the expression of COL1A1.

CONCLUSIONS

While there was an age-dependent increase in markers of cellular senescence, this relationship was not consistently seen across all markers and tissues. Dasatinib + quercetin had moderate efficacy in decreasing senescence in these tissues and increasing COL1A1 expression.

CLINICAL RELEVANCE

This study reveals that cellular senescence may be a therapeutic target to alter the biological aging of rotator cuffs and identifies D+Q as a potential therapy.

A Review on the Efficacy of Plant-derived Bio-active Compounds Curcumin and Aged Garlic Extract in Modulating Cancer and Age-related Diseases

Aging is a process characterized by accumulating degenerative changes resulting in the death of an organism. Aging is mediated by various pathways that are directly linked to the individual's lifespan and are shunted for many age-related diseases. Many strategies for alleviating age-related diseases have been studied, which can target cells and molecules. Modern drugs such as Metformin, Rapamycin, and other drugs are used to reduce the effects of age-related diseases. Despite their beneficial activity, they possess some side effects which can limit their applications, mainly in older adults. Natural phytochemicals which have anti-aging activities have been studied by many researchers from a broader aspect and suggested that plant-based compounds can be a possible, direct, and practical way to treat age-related diseases which has enormous anti-aging activity. Also, studies indicated that the synergistic action of phytochemicals might enhance the biological effect rather than the individual or summative effects of natural compounds. Curcumin has an antioxidant property and is an effective scavenger of reactive oxygen species. Curcumin also has a beneficial role in many age-related diseases like diabetes, cardiovascular disease, neurological disorder, and cancer. Aged garlic extracts are also another bioactive component that has high antioxidant properties. Many studies demonstrated aged garlic extract, which has high antioxidant properties, could play a significant role in anti-aging and age-related diseases. The synergistic effect of these compounds can decrease the requirement of doses of a single drug, thus reducing its side effects caused by increased concentration of the single drug.

Senescence Targeting Methods Impact Alzheimer's Disease Features in 3xTg Mice

Background

Cellular senescence has been associated with neurodegenerative disease and clearance of senescent cells using genetic or pharmaceutical strategies (senolytics) has demonstrated beneficial effects in mouse models investigating individual disease etiologies of Alzheimer's disease (AD). However, it has remained unclear if senescent cell clearance in a mouse model exhibiting both plaque and tau pathologies modifies the disease state (3xTg).

Objective

To investigate the effects of senescent cell clearance in the 3xTg mouse model.

Methods

3xTg mice were treated with senolytics (ABT263 (navitoclax; NAVI), a combination of dasatinib and quercetin (D+Q)), or subjected to transgene-mediated removal of p16-expressing cells (via INK-ATTAC).

Results

Senolytic treatments consistently reduced microgliosis and ameliorated both amyloid and tau pathology in 3xTg mice. Using RNA sequencing, we found evidence that synaptic dysfunction and neuroinflammation were attenuated with treatment. These beneficial effects were not observed with short-term senolytic treatment in mice with more advanced disease.

Conclusions

Overall, our results further corroborate the beneficial effects senescent cell clearance could have on AD and highlight the importance of early intervention for the treatment of this debilitating disease.

Targeting accelerated pulmonary ageing to treat chronic obstructive pulmonary disease-induced neuropathological comorbidities

Chronic obstructive pulmonary disease (COPD) is a major incurable health burden, ranking as the third leading cause of death worldwide, mainly driven by cigarette smoking. COPD is characterised by persistent airway inflammation, lung function decline and premature ageing with the presence of pulmonary senescent cells. This review proposes that cellular senescence, a state of stable cell cycle arrest linked to ageing, induced by inflammation and oxidative stress in COPD, extends beyond the lungs and affects the systemic circulation. This pulmonary senescent profile will reach other organs via extracellular vesicles contributing to brain inflammation and damage, and increasing the risk of neurological comorbidities, such as stroke, cerebral small vessel disease and Alzheimer's disease. The review explores the role of cellular senescence in COPD-associated brain conditions and investigates the relationship between cellular senescence and circadian rhythm in COPD. Additionally, it discusses potential therapies, including senomorphic and senolytic treatments, as novel strategies to halt or improve the progression of COPD.

Rutin is a potent senomorphic agent to target senescent cells and can improve chemotherapeutic efficacy

Aging is a major risk factor for most chronic disorders, for which cellular senescence is one of the central hallmarks. Senescent cells develop the pro-inflammatory senescence-associated secretory phenotype (SASP), which significantly contributes to organismal aging and age-related disorders. Development of senotherapeutics, an emerging class of therapeutic agents to target senescent cells, allows to effectively delay aging and alleviate chronic pathologies. Here we report preliminary outputs from screening of a natural medicinal agent (NMA) library for senotherapeutic candidates and validated several agents with prominent potential as senomorphics. Rutin, a phytochemical constituent found in a number of plants, showed remarkable capacity in targeting senescent cells by dampening expression of the full spectrum SASP. Further analysis indicated that rutin restrains the acute stress-associated phenotype (ASAP) by specifically interfering with the interactions of ATM with HIF1α, a master regulator of cellular and systemic homeostasis activated during senescence, and of ATM with TRAF6, part of a key signaling axis supporting the ASAP development toward the SASP. Conditioned media produced by senescent stromal cells enhanced the malignant phenotypes of prostate cancer cells, including in vitro proliferation, migration, invasion, and more importantly, chemoresistance, while rutin remarkably downregulated these gain-of-functions. Although classic chemotherapy reduced tumor progression, the treatment outcome was substantially improved upon combination of a chemotherapeutic agent with rutin. Our study provides a proof of concept for rutin as an emerging natural senomorphic agent, and presents an effective therapeutic avenue for alleviating age-related pathologies including cancer.

Therapeutic Potential and Clinical Effectiveness of Quercetin: A Dietary Supplement

Fruits and vegetables (like apples, citrus, grapes, onions, parsley, etc.) are the primary dietary sources of quercetin. In addition, isolated quercetin is also available on the market as a dietary supplement with a daily dose of up to 1000 mg/d. The objective of the present study is to explore the therapeutic potential and clinical efficacy of quercetin as a dietary supplement. The present paper highlights the safety parameters and clinical trial studies with several targets reviewed from the data available on PubMed, Science Direct, ClinicalTrails. gov, and from many reputed foundations. The results of the studies prove the unique position of quercetin in the treatment of various disorders and the possibility of using phytochemicals such as quercetin for an efficient cure. As evidenced by the numerous published reports on human interventions, it has been concluded that quercetin intake significantly improves disease conditions with minimal adverse effects.

The Plastic Interplay between Lung Regeneration Phenomena and Fibrotic Evolution: Current Challenges and Novel Therapeutic Perspectives

Interstitial lung diseases (ILDs) are a heterogeneous group of pulmonary disorders characterized by variable degrees of inflammation, interstitial thickening, and fibrosis leading to distortion of the pulmonary architecture and gas exchange impairment. Among them, idiopathic pulmonary fibrosis (IPF) displays the worst prognosis. The only therapeutic options consist of the two antifibrotic drugs, pirfenidone and nintedanib, which limit fibrosis progression but do not reverse the lung damage. The shift of the pathogenetic paradigm from inflammatory disease to epithelium-derived disease has definitively established the primary role of type II alveolar cells, which lose their epithelial phenotype and acquire a mesenchymal phenotype with production of collagen and extracellular matrix (EMC) deposition. Some predisposing environmental and genetic factors (e.g., smoke, pollution, gastroesophageal reflux, variants of telomere and surfactant genes) leading to accelerated senescence set a pro-fibrogentic microenvironment and contribute to the loss of regenerative properties of type II epithelial cells in response to pathogenic noxae. This review provides a complete overview of the different pathogenetic mechanisms leading to the development of IPF. Then, we summarize the currently approved therapies and the main clinical trials ongoing. Finally, we explore the potentialities offered by agents not only interfering with the processes of fibrosis but also restoring the physiological properties of alveolar regeneration, with a particular focus on potentialities and concerns about cell therapies based on mesenchymal stem cells (MSCs), whose anti-inflammatory and immunomodulant properties have been exploited in other fibrotic diseases, such as graft versus host disease (GVHD) and COVID-19-related ARDS.

Age-related decline in spermatogenic activity accompanied with endothelial cell senescence in male mice

Male fertility decreases with aging, with spermatogenic decline being one of its causes. Altered testis environment is suggested as a cause of the phenotype; however, the associated mechanisms remain unclear. Herein, we investigated the age-related changes in testicular somatic cells on spermatogenic activity. The number and proliferation of spermatogonia significantly reduced with aging in mice. Interestingly, senescence-associated β-galactosidase-positive cells appeared in testicular endothelial cell (EC) populations, but not in germ cell populations, with aging. Transcriptome analysis of ECs indicated that senescence occurred in the ECs of aged mice. Furthermore, the support capacity of ECs for spermatogonial proliferation significantly decreased with aging; however, the senolytic-induced removal of senescent cells from aged ECs restored their supporting capacity to a comparable level as that of young ECs. Our results suggest that the accumulation of senescent ECs in the testis is a potential factor contributing to the age-related decline in spermatogenic activity.

Lipophilic Statins Eliminate Senescent Endothelial Cells by inducing Anoikis-Related Cell Death

Pre-clinical studies from the recent past have indicated that senescent cells can negatively affect health and contribute to premature aging. Targeted eradication of these cells has been shown to improve the health of aged experimental animals, leading to a clinical interest in finding compounds that selectively eliminate senescent cells while sparing non-senescent ones. In our study, we identified a senolytic capacity of statins, which are lipid-lowering drugs prescribed to patients at high risk of cardiovascular events. Using two different models of senescence in human vascular endothelial cells (HUVECs), we found that statins preferentially eliminated senescent cells, while leaving non-senescent cells unharmed. We observed that the senolytic effect of statins could be negated with the co-administration of mevalonic acid and that statins induced cell detachment leading to anoikis-like apoptosis, as evidenced by real-time visualization of caspase-3/7 activation. Our findings suggest that statins possess a senolytic property, possibly also contributing to their described beneficial cardiovascular effects. Further studies are needed to explore the potential of short-term, high-dose statin treatment as a candidate senolytic therapy.

The stromal microenvironment and ovarian aging: mechanisms and therapeutic opportunities

For decades, most studies of ovarian aging have focused on its functional units, known as follicles, which include oocytes and granulosa cells. However, in the ovarian stroma, there are a variety of somatic components that bridge the gap between general aging and ovarian senescence. Physiologically, general cell types, microvascular structures, extracellular matrix, and intercellular molecules affect folliculogenesis and corpus luteum physiology alongside the ovarian cycle. As a result of damage caused by age-related metabolite accumulation and external insults, the microenvironment of stromal cells is progressively remodeled, thus inevitably perturbing ovarian physiology. With the established platforms for follicle cryopreservation and in vitro maturation and the development of organoid research, it is desirable to develop strategies to improve the microenvironment of the follicle by targeting the perifollicular environment. In this review, we summarize the role of stromal components in ovarian aging, describing their age-related alterations and associated effects. Moreover, we list some potential techniques that may mitigate ovarian aging based on their effect on the stromal microenvironment.

Flavonoids Regulate Redox-Responsive Transcription Factors in Glioblastoma and Microglia

The tumor microenvironment (TME) has emerged as a valuable therapeutic target in glioblastoma (GBM), as it promotes tumorigenesis via an increased production of reactive oxygen species (ROS). Immune cells such as microglia accumulate near the tumor and its hypoxic core, fostering tumor proliferation and angiogenesis. In this study, we explored the therapeutic potential of natural polyphenols with antioxidant and anti-inflammatory properties. Notably, flavonoids, including fisetin and quercetin, can protect non-cancerous cells while eliminating transformed cells (2D cultures and 3D tumoroids). We tested the hypothesis that fisetin and quercetin are modulators of redox-responsive transcription factors, for which subcellular location plays a critical role. To investigate the sites of interaction between natural compounds and stress-responsive transcription factors, we combined molecular docking with experimental methods employing proximity ligation assays. Our findings reveal that fisetin decreased cytosolic acetylated high mobility group box 1 (acHMGB1) and increased transcription factor EB (TFEB) abundance in microglia but not in GBM. Moreover, our results suggest that the most powerful modulator of the Nrf2-KEAP1 complex is fisetin. This finding is in line with molecular modeling and calculated binding properties between fisetin and Nrf2-KEAP1, which indicated more sites of interactions and stronger binding affinities than quercetin.

The Role of Cellular Senescence in Cyclophosphamide-Induced Primary Ovarian Insufficiency

Young female cancer patients can develop chemotherapy-induced primary ovarian insufficiency (POI). Cyclophosphamide (Cy) is one of the most widely used chemotherapies and has the highest risk of damaging the ovaries. Recent studies elucidated the pivotal roles of cellular senescence, which is characterized by permanent cell growth arrest, in the pathologies of various diseases. Moreover, several promising senolytics, including dasatinib and quercetin (DQ), which remove senescent cells, are being developed. In the present study, we investigated whether cellular senescence is involved in Cy-induced POI and whether DQ treatment rescues Cy-induced ovarian damage. Expression of the cellular senescence markers p16, p21, p53, and γH2AX was upregulated in granulosa cells of POI mice and in human granulosa cells treated with Cy, which was abrogated by DQ treatment. The administration of Cy decreased the numbers of primordial and primary follicles, with a concomitant increase in the ratio of growing to dormant follicles, which was partially rescued by DQ. Moreover, DQ treatment significantly improved the response to ovulation induction and fertility in POI mice by extending reproductive life. Thus, cellular senescence plays critical roles in Cy-induced POI, and targeting senescent cells with senolytics, such as DQ, might be a promising strategy to protect against Cy-induced ovarian damage.

Cellular microenvironment: a key for tuning mesenchymal stem cell senescence

Mesenchymal stem cells (MSCs) possess the ability to self-renew and differentiate into multiple cell types, making them highly suitable for use as seed cells in tissue engineering. These can be derived from various sources and have been found to play crucial roles in several physiological processes, such as tissue repair, immune regulation, and intercellular communication. However, the limited capacity for cell proliferation and the secretion of senescence-associated secreted phenotypes (SASPs) pose challenges for the clinical application of MSCs. In this review, we provide a comprehensive summary of the senescence characteristics of MSCs and examine the different features of cellular microenvironments studied thus far. Additionally, we discuss the mechanisms by which cellular microenvironments regulate the senescence process of MSCs, offering insights into preserving their functionality and enhancing their effectiveness.

Cellular senescence and frailty: a comprehensive insight into the causal links

Senescent cells may have a prominent role in driving inflammation and frailty. The impact of cellular senescence on frailty varies depending on the assessment tool used, as it is influenced by the criteria or items predominantly affected by senescent cells and the varying weights assigned to these items across different health domains. To address this challenge, we undertook a thorough review of all available studies involving gain- or loss-of-function experiments as well as interventions targeting senescent cells, focusing our attention on those studies that examined outcomes based on the individual frailty phenotype criteria or specific items used to calculate two humans (35 and 70 items) and one mouse (31 items) frailty indexes. Based on the calculation of a simple "evidence score," we found that the burden of senescent cells related to musculoskeletal and cerebral health has the strongest causal link to frailty. We deem that insight into these mechanisms may not only contribute to clarifying the role of cellular senescence in frailty but could additionally provide multiple therapeutic opportunities to help the future development of a desirable personalized therapy in these extremely heterogeneous patients.

Pharmacological modulation of vascular ageing: A review from VascAgeNet

Vascular ageing, characterized by structural and functional changes in blood vessels of which arterial stiffness and endothelial dysfunction are key components, is associated with increased risk of cardiovascular and other age-related diseases. As the global population continues to age, understanding the underlying mechanisms and developing effective therapeutic interventions to mitigate vascular ageing becomes crucial for improving cardiovascular health outcomes. Therefore, this review provides an overview of the current knowledge on pharmacological modulation of vascular ageing, highlighting key strategies and promising therapeutic targets. Several molecular pathways have been identified as central players in vascular ageing, including oxidative stress and inflammation, the renin-angiotensin-aldosterone system, cellular senescence, macroautophagy, extracellular matrix remodelling, calcification, and gasotransmitter-related signalling. Pharmacological and dietary interventions targeting these pathways have shown potential in ameliorating age-related vascular changes. Nevertheless, the development and application of drugs targeting vascular ageing is complicated by various inherent challenges and limitations, such as certain preclinical methodological considerations, interactions with exercise training and sex/gender-related differences, which should be taken into account. Overall, pharmacological modulation of endothelial dysfunction and arterial stiffness as hallmarks of vascular ageing, holds great promise for improving cardiovascular health in the ageing population. Nonetheless, further research is needed to fully elucidate the underlying mechanisms and optimize the efficacy and safety of these interventions for clinical translation.

Status of Research on Sestrin2 and Prospects for its Application in Therapeutic Strategies Targeting Myocardial Aging

Cardiac aging is accompanied by changes in the heart at the cellular and molecular levels, leading to alterations in cardiac structure and function. Given today's increasingly aging population, the decline in cardiac function caused by cardiac aging has a significant impact on quality of life. Antiaging therapies to slow the aging process and attenuate changes in cardiac structure and function have become an important research topic. Treatment with drugs, including metformin, spermidine, rapamycin, resveratrol, astaxanthin, Huolisu oral liquid, and sulforaphane, has been demonstrated be effective in delaying cardiac aging by stimulating autophagy, delaying ventricular remodeling, and reducing oxidative stress and the inflammatory response. Furthermore, caloric restriction has been shown to play an important role in delaying aging of the heart. Many studies in cardiac aging and cardiac aging-related models have demonstrated that Sestrin2 has antioxidant and anti-inflammatory effects, stimulates autophagy, delays aging, regulates mitochondrial function, and inhibits myocardial remodeling by regulation of relevant signaling pathways. Therefore, Sestrin2 is likely to become an important target for antimyocardial aging therapy.

What matters in aging is signaling for responsiveness

Biological responsiveness refers to the capacity of living organisms to adapt to changes in both their internal and external environments through physiological and behavioral mechanisms. One of the prominent aspects of aging is the decline in this responsiveness, which can lead to a deterioration in the processes required for maintenance, survival, and growth. The vital link between physiological responsiveness and the essential life processes lies within the signaling systems. To devise effective strategies for controlling the aging process, a comprehensive reevaluation of this connecting loop is imperative. This review aims to explore the impact of aging on signaling systems responsible for responsiveness and introduce a novel perspective on intervening in the aging process by restoring the compromised responsiveness. These innovative mechanistic approaches for modulating altered responsiveness hold the potential to illuminate the development of action plans aimed at controlling the aging process and treating age-related disorders.

Immunosenescence and macrophages: From basics to therapeutics

Ageing decreases the function of the immune system and increases susceptibility to some chronic, infectious, and autoimmune diseases. Senescence cells, which produce senescence-associated secretory phenotypes (SASPs), can activate the innate and adaptive immune responses. Macrophages are among the most abundant innate immune cell types in senescent microenvironments. Senescence-associated macrophages, recruited by SASPs, play a vital role in establishing the essential microenvironments for maintaining tissue homeostasis. However, it's important to note that these senescence-associated macrophages can also influence senescent processes, either by enhancing or impeding the functions of tissue-resident senescent cells. In this discussion, we describe the potential targets of immunosenescence and shed light on the probable mechanisms by which macrophages influence cellular senescence. Furthermore, we analyze their dual function in both clearing senescent cells and modulating age-related diseases. This multifaceted influence operates through processes including heightened inflammation, phagocytosis, efferocytosis, and autophagy. Given the potential off-target effects and immune evasion mechanisms associated with traditional anti-ageing strategies (senolytics and senomorphics), 'resetting' immune system tolerance or targeting senescence-related macrophage functions (i.e., phagocytotic capacity and immunosurveillance) will inform treatment of age-related diseases. Therefore, we review recent advances in the use of macrophage therapeutics to treat ageing and age-associated disorders, and outline the key gaps in this field.

Tissue Engineering of JAK Inhibitor-Loaded Hierarchically Biomimetic Nanostructural Scaffold Targeting Cellular Senescence for Aged Bone Defect Repair and Bone Remolding

Cell senescence or apoptosis contributes to self-failure and functional loss in specialized cells, leading to incapacity of the body to repair specific damages. Senescent bone marrow mesenchymal stem cells (BMSCs) lose their proliferative abilities and secrete senescence-associated secretory phenotype (SASP), hindering their participation in bone defect repair. Hence, the effective suppression of cell senescence is crucial to restore the self-repair capacity of body to treat bone defects. Since the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway is associated with SASP secretion, herein, a new strategy is proposed to inhibit this pathway to suppress SASP secretion and enhance osteoblast activity based on a novel hierarchically biomimetic nanostructural electrospun scaffold with JAK inhibitors (JAKi, Ruxolitinib) loaded. As validated by in vitro and in vivo experiments, the JAKi loaded scaffold reduces SASP expression effectively and alleviates senescent cell burden, creating a pro-regeneration microenvironment that enhances osteoblast function and mineralization activity as well as rejuvenating the bone repair capacity. These findings offer insights into the regulatory role of cellular senescence in bone aging and provide a new and effective strategy to treat age-related bone defects by delivery of JAKi to locally aging bone defect sites.

Current and investigational medications for the treatment of sarcopenia

Sarcopenia, defined as the loss of muscle mass and function, is a widely prevalent and severe condition in older adults. Since 2016, it is recognized as a disease. Strength exercise training and nutritional support are the frontline treatment of sarcopenia, with no drug currently approved for this indication. However, new therapeutic options are emerging. In this review, we evidenced that only very few trials have focused on sarcopenia/sarcopenic patients. Most drug trials were performed in different clinical older populations (e.g., men with hypogonadism, post-menopausal women at risk for osteoporosis), and their efficacy were tested separately on the components of sarcopenia (muscle mass, muscle strength and physical performances). Results from trials testing the effects of Testosterone, Selective Androgen Receptor Modulators (SARMs), Estrogen, Dehydroepiandrosterone (DHEA), Insulin-like Growth Factor-1 (IGF-1), Growth Hormone (GH), GH Secretagogue (GHS), drug targeting Myostatin and Activin receptor pathway, Vitamin D, Angiotensin Converting Enzyme inhibitors (ACEi) and Angiotensin Receptor Blockers (ARBs), or β-blockers, were compiled. Although some drugs have been effective in improving muscle mass and/or strength, this was not translated into clinically relevant improvements on physical performance. Finally, some promising molecules investigated in on-going clinical trials and in pre-clinical phase were summarized, including apelin and irisin.

COPI vesicle formation and N-myristoylation are targetable vulnerabilities of senescent cells

Drugs that selectively kill senescent cells (senolytics) improve the outcomes of cancer, fibrosis and age-related diseases. Despite their potential, our knowledge of the molecular pathways that affect the survival of senescent cells is limited. To discover senolytic targets, we performed RNAi screens and identified coatomer complex I (COPI) vesicle formation as a liability of senescent cells. Genetic or pharmacological inhibition of COPI results in Golgi dispersal, dysfunctional autophagy, and unfolded protein response-dependent apoptosis of senescent cells, and knockdown of COPI subunits improves the outcomes of cancer and fibrosis in mouse models. Drugs targeting COPI have poor pharmacological properties, but we find that N-myristoyltransferase inhibitors (NMTi) phenocopy COPI inhibition and are potent senolytics. NMTi selectively eliminated senescent cells and improved outcomes in models of cancer and non-alcoholic steatohepatitis. Our results suggest that senescent cells rely on a hyperactive secretory apparatus and that inhibiting trafficking kills senescent cells with the potential to treat various senescence-associated diseases.

Resilience, aging, and response to radiation exposure (RARRE) in nonhuman primates: a resource review

The Wake Forest nonhuman primate (NHP) Radiation Late Effects Cohort (RLEC) is a unique and irreplaceable population of aging NHP radiation survivors which serves the nation's need to understand the late effects of radiation exposure. Over the past 16 years, Wake Forest has evaluated > 250 previously irradiated rhesus macaques (Macaca mulatta) that were exposed to single total body irradiation (IR) doses of 1.14-8.5 Gy or to partial body exposures of up to 10 Gy (5% bone marrow sparing) or 10.75 Gy (whole thorax). Though primarily used to examine IR effects on disease-specific processes or to develop radiation countermeasures, this resource provides insights on resilience across physiologic systems and its relationship with biological aging. Exposure to IR has well documented deleterious effects on health, but the late effects of IR are highly variable. Some animals exhibit multimorbidity and accumulated health deficits, whereas others remain relatively resilient years after exposure to total body IR. This provides an opportunity to evaluate biological aging at the nexus of resilient/vulnerable responses to a stressor. Consideration of inter-individual differences in response to this stressor can inform individualized strategies to manage late effects of radiation exposure, and provide insight into mechanisms underlying systemic resilience and aging. The utility of this cohort for age-related research questions was summarized at the 2022 Trans-NIH Geroscience Interest Group's Workshop on Animal Models for Geroscience. We present a brief review of radiation injury and its relationship to aging and resilience in NHPs with a focus on the RLEC.

Targeting the redox system for cardiovascular regeneration in aging

Cardiovascular aging presents a formidable challenge, as the aging process can lead to reduced cardiac function and heightened susceptibility to cardiovascular diseases. Consequently, there is an escalating, unmet medical need for innovative and effective cardiovascular regeneration strategies aimed at restoring and rejuvenating aging cardiovascular tissues. Altered redox homeostasis and the accumulation of oxidative damage play a pivotal role in detrimental changes to stem cell function and cellular senescence, hampering regenerative capacity in aged cardiovascular system. A mounting body of evidence underscores the significance of targeting redox machinery to restore stem cell self-renewal and enhance their differentiation potential into youthful cardiovascular lineages. Hence, the redox machinery holds promise as a target for optimizing cardiovascular regenerative therapies. In this context, we delve into the current understanding of redox homeostasis in regulating stem cell function and reprogramming processes that impact the regenerative potential of the cardiovascular system. Furthermore, we offer insights into the recent translational and clinical implications of redox-targeting compounds aimed at enhancing current regenerative therapies for aging cardiovascular tissues.

An untapped window of opportunity for glioma: targeting therapy-induced senescence prior to recurrence

High-grade gliomas are primary brain tumors that are incredibly refractory long-term to surgery and chemoradiation, with no proven durable salvage therapies for patients that have failed conventional treatments. Post-treatment, the latent glioma and its microenvironment are characterized by a senescent-like state of mitotic arrest and a senescence-associated secretory phenotype (SASP) induced by prior chemoradiation. Although senescence was once thought to be irreversible, recent evidence has demonstrated that cells may escape this state and re-enter the cell cycle, contributing to tumor recurrence. Moreover, senescent tumor cells could spur the growth of their non-senescent counterparts, thereby accelerating recurrence. In this review, we highlight emerging evidence supporting the use of senolytic agents to ablate latent, senescent-like cells that could contribute to tumor recurrence. We also discuss how senescent cell clearance can decrease the SASP within the tumor microenvironment thereby reducing tumor aggressiveness at recurrence. Finally, senolytics could improve the long-term sequelae of prior therapy on cognition and bone marrow function. We critically review the senolytic drugs currently under preclinical and clinical investigation and the potential challenges that may be associated with deploying senolytics against latent glioma. In conclusion, senescence in glioma and the microenvironment are critical and potential targets for delaying or preventing tumor recurrence and improving patient functional outcomes through senotherapeutics.

Cellular senescence in brain aging and cognitive decline

Cellular senescence is a biological aging hallmark that plays a key role in the development of neurodegenerative diseases. Clinical trials are currently underway to evaluate the effectiveness of senotherapies for these diseases. However, the impact of senescence on brain aging and cognitive decline in the absence of neurodegeneration remains uncertain. Moreover, patient populations like cancer survivors, traumatic brain injury survivors, obese individuals, obstructive sleep apnea patients, and chronic kidney disease patients can suffer age-related brain changes like cognitive decline prematurely, suggesting that they may suffer accelerated senescence in the brain. Understanding the role of senescence in neurocognitive deficits linked to these conditions is crucial, especially considering the rapidly evolving field of senotherapeutics. Such treatments could help alleviate early brain aging in these patients, significantly reducing patient morbidity and healthcare costs. This review provides a translational perspective on how cellular senescence plays a role in brain aging and age-related cognitive decline. We also discuss important caveats surrounding mainstream senotherapies like senolytics and senomorphics, and present emerging evidence of hyperbaric oxygen therapy and immune-directed therapies as viable modalities for reducing senescent cell burden.

High-Level Secretion of Pregnancy Zone Protein Is a Novel Biomarker of DNA Damage-Induced Senescence and Promotes Spontaneous Senescence

Identification of unique and specific biomarkers to better detect and quantify senescent cells remains challenging. By a global proteomic profiling of senescent human skin BJ fibroblasts induced by ionizing radiation (IR), the cellular level of pregnancy zone protein (PZP), a presumable pan-protease inhibitor never been linked to cellular senescence before, was found to be decreased by more than 10-fold, while the level of PZP in the conditioned medium was increased concomitantly. This observation was confirmed in a variety of senescent cells induced by IR or DNA-damaging drugs, indicating that high-level secretion of PZP is a novel senescence-associated secretory phenotype. RT-PCR examination verified that the transcription of the PZP gene is enhanced in various cells at senescence or upregulated following DNA damage treatment in a p53-independent manner. Moreover, pretreatment with late pregnancy serum containing a high level of PZP led to inhibition of doxorubicin-induced senescence in A549 cells, and depletion of PZP in the pregnancy serum could enhance such inhibition. Finally, the addition of immuno-precipitated PZP complexes into tissue culture attenuated the growth of A549 cells and promoted the spontaneous senescence. Therefore, we revealed that high-level secretion of PZP is a novel and unique feature associated with DNA damage-induced senescence, and secreted PZP is a positive regulator of cellular senescence, particularly during the late stage of gestation.

Relationship between an ageing measure and chronic obstructive pulmonary disease, lung function: a cross-sectional study of NHANES, 2007-2010

OBJECTIVES

Chronic obstructive pulmonary disease (COPD) is a disease associated with ageing. However, actual age does not accurately reflect the degree of biological ageing. Phenotypic age (PhenoAge) is a new indicator of biological ageing, and phenotypic age minus actual age is known as phenotypic age acceleration (PhenoAgeAccel). This research aimed to analyse the relationship between PhenoAgeAccel and lung function and COPD.

DESIGN

A cross-sectional study.

PARTICIPANTS

Data for the study were obtained from the National Health and Nutrition Examination Survey (NHANES) 2007-2010. We defined people with forced expiratory volume in 1 s/forced vital capacity <0.70 after inhaled bronchodilators as COPD and the rest of the population as non-COPD. Adults aged 40 years or older were enrolled in the study.

PRIMARY AND SECONDARY OUTCOME MEASURES

Linear and logistic regression were used to investigate the relationship between PhenoAgeAccel, lung function and COPD. Subgroup analysis was performed by gender, age, ethnicity and smoking index COPD. In addition, we analysed the relationship between the smoking index, respiratory symptoms and PhenoAgeAccel. Multiple models were used to reduce confounding bias.

RESULTS

5397 participants were included in our study, of which 1042 had COPD. Compared with PhenoAgeAccel Quartile1, Quartile 4 had a 52% higher probability of COPD; elevated PhenoAgeAccel was also significantly associated with reduced lung function. Further subgroup analysis showed that high levels of PhenoAgeAccel had a more significant effect on lung function in COPD, older adults and whites (P for interaction <0.05). Respiratory symptoms and a high smoking index were related to higher indicators of ageing.

CONCLUSIONS

Our study found that accelerated ageing is associated with the development of COPD and impaired lung function. Smoking cessation and anti-ageing therapy have potential significance in COPD.

Frentizole derivatives with mTOR inhibiting and senomorphic properties

Frentizole is immunosuppressive drug with low acute toxicity and lifespan-prolonging effect. Recently, frentizole´s potential to disrupt toxic amyloid β (Aβ) - Aβ-binding alcohol dehydrogenase (ABAD) interaction in mitochondria in Alzheimer´s brains has been revealed. Another broadly studied drug with anti-aging and immunosuppressive properties is an mTOR inhibitor - rapamycin. Since we do not yet precisely know what is behind the lifespan-prolonging effect of rapamycin and frentizole, whether it is the ability to inhibit the mTOR signaling pathway, reduction in mitochondrial toxicity, immunosuppressive effect, or a combination of all of them, we have decided within our previous work to dock the entire in-house library of almost 240 Aβ-ABAD modulators into the FKBP-rapamycin-binding (FRB) domain of mTOR in order to interlink mTOR-centric and mitochondrial free radical-centric theories of aging and thus to increase the chances of success. Based on the results of the docking study, molecular dynamic simulation and MM-PBSA calculations, we have selected nine frentizole-like compounds (1 - 9). Subsequently, we have determined their real physical-chemical properties (logP, logD, pKa and solubility in water and buffer), cytotoxic/cytostatic, mTOR inhibitory, and in vitro anti-senescence (senolytic and senomorphic) effects. Finally, the three best candidates (4, 8, and 9) have been forwarded for in vivo safety studies to assess their acute toxicity and pharmacokinetic properties. Based on obtained results, only compound 4 demonstrated the best results within in vitro testing, the ability to cross the blood-brain barrier and the lowest acute toxicity (LD50 in male mice 559 mg/kg; LD50 in female mice 575 mg/kg).

Identification and functional analysis of senescent cells in the cardiovascular system using omics approaches

Cardiovascular disease (CVD) is a leading cause of morbidity and mortality worldwide, and senescent cells have emerged as key contributors to its pathogenesis. Senescent cells exhibit cell cycle arrest and secrete a range of proinflammatory factors, termed the senescence-associated secretory phenotype (SASP), which promotes tissue dysfunction and exacerbates CVD progression. Omics technologies, specifically transcriptomics and proteomics, offer powerful tools to uncover and define the molecular signatures of senescent cells in cardiovascular tissue. By analyzing the comprehensive molecular profiles of senescent cells, omics approaches can identify specific genetic alterations, gene expression patterns, protein abundances, and metabolite levels associated with senescence in CVD. These omics-based discoveries provide insights into the mechanisms underlying senescence-induced cardiovascular damage, facilitating the development of novel diagnostic biomarkers and therapeutic targets. Furthermore, integration of multiple omics data sets enables a systems-level understanding of senescence in CVD, paving the way for precision medicine approaches to prevent or treat cardiovascular aging and its associated complications.

A novel BRD4 degrader, ARV-825, attenuates lung fibrosis through senolysis and antifibrotic effect

BACKGROUND

Recent studies suggest that cellular senescence is related to the pathogenesis of idiopathic pulmonary fibrosis. However, cellular senescence has yet to be targeted therapeutically in clinical practice. ARV825, a recently developed BRD4 degrader, has been reported as a novel senolytic drug. Conversely, it has also been reported that BRD4 regulates the pro-fibrotic gene expression of fibroblasts. Therefore, this study focuses on the senolytic and anti-fibrotic effects of ARV825 and evaluated these effects on lung fibrosis.

METHODS

Lung fibroblasts were induced to senescence through serial passage. The expression of senescence markers and pro-fibrotic markers were determined through quantitative PCR or immunoblot analysis. Lung fibrosis was induced in mice through intratracheal administration of bleomycin. Mice treated with ARV825 underwent histological analysis of lung fibrosis using the Ashcroft score. Total lung collagen was quantified through a hydroxyproline assay. Respiratory mechanics analysis was performed using the flexiVent system.

RESULTS

For senescent cells, ARV825 induced the expression of an apoptosis marker while reducing the expression of BRD4 and senescence markers. On the other hand, for early passage pre-senescent cells, ARV825 reduced the expression of collagen type 1 and α-smooth muscle actin. In an experimental mouse model of lung fibrosis, ARV825 attenuated lung fibrosis and improved lung function. Immunohistochemical staining revealed a significant decrease in the number of senescent alveolar type 2 cells in lung tissue due to ARV825 treatment.

CONCLUSIONS

These results suggest that ARV825 may impact the progressive and irreversible course of fibrotic lung diseases.

Idiopathic pulmonary fibrosis: Addressing the current and future therapeutic advances along with the role of Sotatercept in the management of pulmonary hypertension

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive and debilitating lung disease characterized by irreversible scarring of the lungs. The cause of IPF is unknown, but it is thought to involve a combination of genetic and environmental factors. There is no cure for IPF, and treatment is focused on slowing disease progression and relieving symptoms.

AIMS

We aimed in this review to investigate and provide the latest insights into IPF management modalities, including the potential of Saracatinibas a substitute for current IPF drugs. We also investigated the therapeutic potential of Sotatercept in addressing pulmonary hypertension associated with IPF.

MATERIALS AND METHODS

We conducted a comprehensive literature review of relevant studies on IPF management. We searched electronic databases, including PubMed, Scopus, Embase, and Web of science.

RESULTS

The two Food and Drug Administration-approved drugs for IPF, Pirfenidone, and Nintedanib, have been pivotal in slowing disease progression, yet experimental evidence suggests that Saracatinib surpasses their efficacy. Preclinical trials investigating the potential of Saracatinib, a tyrosine kinase inhibitor, have shown to be more effective than current IPF drugs in slowing disease progression in preclinical studies. Also, Sotatercept,a fusion protein, has been shown to reduce pulmonary vascular resistance and improve exercise tolerance in patients with PH associated with IPF in clinical trials.

CONCLUSIONS

The advancements discussed in this review hold the promise of improving the quality of life for IPF patients and enhancing our understanding of this condition. There remains a need for further research to confirm the efficacy and safety of new IPF treatments and to develop more effective strategies for managing exacerbations.