Cellular senescence and the senescent secretory phenotype: therapeutic opportunities

Targeting brain-peripheral immune responses for secondary brain injury after ischemic and hemorrhagic stroke

The notion that the central nervous system is an immunologically immune-exempt organ has changed over the past two decades, with increasing evidence of strong links and interactions between the central nervous system and the peripheral immune system, both in the healthy state and after ischemic and hemorrhagic stroke. Although primary injury after stroke is certainly important, the limited therapeutic efficacy, poor neurological prognosis and high mortality have led researchers to realize that secondary injury and damage may also play important roles in influencing long-term neurological prognosis and mortality and that the neuroinflammatory process in secondary injury is one of the most important influences on disease progression. Here, we summarize the interactions of the central nervous system with the peripheral immune system after ischemic and hemorrhagic stroke, in particular, how the central nervous system activates and recruits peripheral immune components, and we review recent advances in corresponding therapeutic approaches and clinical studies, emphasizing the importance of the role of the peripheral immune system in ischemic and hemorrhagic stroke.

A new perspective on prostate cancer treatment: the interplay between cellular senescence and treatment resistance

The emergence of resistance to prostate cancer (PCa) treatment, particularly to androgen deprivation therapy (ADT), has posed a significant challenge in the field of PCa management. Among the therapeutic options for PCa, radiotherapy, chemotherapy, and hormone therapy are commonly used modalities. However, these therapeutic approaches, while inducing apoptosis in tumor cells, may also trigger stress-induced premature senescence (SIPS). Cellular senescence, an entropy-driven transition from an ordered to a disordered state, ultimately leading to cell growth arrest, exhibits a dual role in PCa treatment. On one hand, senescent tumor cells may withdraw from the cell cycle, thereby reducing tumor growth rate and exerting a positive effect on treatment. On the other hand, senescent tumor cells may secrete a plethora of cytokines, growth factors and proteases that can affect neighboring tumor cells, thereby exerting a negative impact on treatment. This review explores how radiotherapy, chemotherapy, and hormone therapy trigger SIPS and the nuanced impact of senescent tumor cells on PCa treatment. Additionally, we aim to identify novel therapeutic strategies to overcome resistance in PCa treatment, thereby enhancing patient outcomes.

Cellular senescence imaging and senolysis monitoring in cancer therapy based on a β-galactosidase-activated aggregation-induced emission luminogen

Cellular senescence is a permanent state of cell cycle arrest characterized by increased activity of senescence associated β-galactosidase (SA-β-gal). Notably, cancer cells have been also observed to exhibit the senescence response and are being considered for sequential treatment with pro-senescence therapy followed by senolytic therapy. However, there is currently no effective agent targeting β-galactosidase (β-Gal) for imaging cellular senescence and monitoring senolysis in cancer therapy. Aggregation-induced emission luminogen (AIEgen) demonstrates strong fluorescence, good photostability, and biocompatibility, making it a potential candidate for imaging cellular senescence and monitoring senolysis in cancer therapy when endowed with β-Gal-responsive capabilities. In this study, we introduced a β-Gal-activated AIEgen named QM-β-gal for cellular senescence imaging and senolysis monitoring in cancer therapy. QM-β-gal exhibited good amphiphilic properties and formed aggregates that emitted a fluorescence signal upon β-Gal activation. It showed high specificity towards the activity of β-Gal in lysosomes and successfully visualized DOX-induced senescent cancer cells with intense fluorescence both in vitro and in vivo. Encouragingly, QM-β-gal could image senescent cancer cells in vivo for over 14 days with excellent biocompatibility. Moreover, it allowed for the monitoring of senescent cancer cell clearance during senolytic therapy with ABT263. This investigation indicated the potential of the β-Gal-activated AIEgen, QM-β-gal, as an in vivo approach for imaging cellular senescence and monitoring senolysis in cancer therapy via highly specific and long-term fluorescence imaging. STATEMENT OF SIGNIFICANCE: This work reported a β-galactosidase-activated AIEgen called QM-β-gal, which effectively imaged DOX-induced senescent cancer cells both in vitro and in vivo. QM-β-gal specifically targeted the increased expression and activity of β-galactosidase in senescent cancer cells, localized within lysosomes. It was cleared rapidly before activation but maintained stability after activation in the DOX-induced senescent tumor. The AIEgen exhibited a remarkable long-term imaging capability for senescent cancer cells, lasting over 14 days and enabled monitoring of senescent cancer cell clearance through ABT263-induced apoptosis. This approach held promise for researchers seeking to achieve prolonged imaging of senescent cells in vivo.

Inactivation of a non-canonical gp130 signaling arm attenuates chronic systemic inflammation and multimorbidity induced by a high-fat diet

Interleukin-6 (IL-6) is a major pro-inflammatory cytokine for which the levels in plasma demonstrate a robust correlation with age and body mass index (BMI) as part of the senescence-associated secretory phenotype. IL-6 cytokines also play a crucial role in metabolic homeostasis and regenerative processes, primarily via the canonical STAT3 pathway. Thus, selective modulation of IL-6 signaling may offer a unique opportunity for therapeutic interventions. Recently, we discovered that a non-canonical signaling pathway downstream of tyrosine (Y) 814 within the intracellular domain of gp130, the IL-6 co-receptor, is responsible for the recruitment and activation of SRC family of kinases (SFK). Mice with constitutive genetic inactivation of gp130 Y814 (F814 mice) show accelerated resolution of inflammatory response and superior regenerative outcomes in skin wound healing and posttraumatic models of osteoarthritis. The current study was designed to explore if selective genetic or pharmacological inhibition of the non-canonical gp130-Y814/SFK signaling reduces systemic chronic inflammation and multimorbidity in a high-fat diet (HFD)-induced model of accelerated aging. F814 mice showed significantly reduced inflammatory response to HFD in adipose and liver tissue, with significantly reduced levels of systemic inflammation compared to wild type mice. F814 mice were also protected from HFD-induced bone loss and cartilage degeneration. Pharmacological inhibition of gp130-Y814/SFK in mice on HFD mirrored the effects observed in F814 mice on HFD; furthermore, this pharmacological treatment also demonstrated a marked increase in physical activity levels and protective effects against inflammation-associated suppression of neurogenesis in the brain tissue compared to the control group. These findings suggest that selective inhibition of SFK signaling downstream of gp130 receptor represents a promising strategy to alleviate systemic chronic inflammation. Increased degenerative changes and tissue senescence are inevitable in obese and aged organisms, but we demonstrated that the systemic response and inflammation-associated multi-morbidity can be therapeutically mitigated.

Healthcare on the brink: navigating the challenges of an aging society in the United States

The US healthcare system is at a crossroads. With an aging population requiring more care and a strained system facing workforce shortages, capacity issues, and fragmentation, innovative solutions and policy reforms are needed. This paper aims to spark dialogue and collaboration among healthcare stakeholders and inspire action to meet the needs of the aging population. Through a comprehensive analysis of the impact of an aging society, this work highlights the urgency of addressing this issue and the importance of restructuring the healthcare system to be more efficient, equitable, and responsive.

Underlying Mechanisms and Treatment of Cellular Senescence-Induced Biological Barrier Interruption and Related Diseases

Given its increasing prevalence, aging is of great concern to researchers worldwide. Cellular senescence is a physiological or pathological cellular state caused by aging and a prominent risk factor for the interruption of the integrity and functionality of human biological barriers. Health barriers play an important role in maintaining microenvironmental homeostasis within the body. The senescence of barrier cells leads to barrier dysfunction and age-related diseases. Cellular senescence has been reported to be a key target for the prevention of age-related barrier diseases, including Alzheimer's disease, Parkinson's disease, age-related macular degeneration, diabetic retinopathy, and preeclampsia. Drugs such as metformin, dasatinib, quercetin, BCL-2 inhibitors, and rapamycin have been shown to intervene in cellular senescence and age-related diseases. In this review, we conclude that cellular senescence is involved in age-related biological barrier impairment. We further outline the cellular pathways and mechanisms underlying barrier impairment caused by cellular senescence and describe age-related barrier diseases associated with senescent cells. Finally, we summarize the currently used anti-senescence pharmacological interventions and discuss their therapeutic potential for preventing age-related barrier diseases.

Senescence, regulators of alternative splicing and effects of trametinib treatment in progeroid syndromes

Progeroid syndromes such as Hutchinson Gilford Progeroid syndrome (HGPS), Werner syndrome (WS) and Cockayne syndrome (CS), result in severely reduced lifespans and premature ageing. Normal senescent cells show splicing factor dysregulation, which has not yet been investigated in syndromic senescent cells. We sought to investigate the senescence characteristics and splicing factor expression profiles of progeroid dermal fibroblasts. Natural cellular senescence can be reversed by application of the senomorphic drug, trametinib, so we also investigated its ability to reverse senescence characteristics in syndromic cells. We found that progeroid cultures had a higher senescence burden, but did not always have differences in levels of proliferation, DNA damage repair and apoptosis. Splicing factor gene expression appeared dysregulated across the three syndromes. 10 µM trametinib reduced senescent cell load and affected other aspects of the senescence phenotype (including splicing factor expression) in HGPS and Cockayne syndromes. Werner syndrome cells did not demonstrate changes in in senescence following treatment. Splicing factor dysregulation in progeroid cells provides further evidence to support this mechanism as a hallmark of cellular ageing and highlights the use of progeroid syndrome cells in the research of ageing and age-related disease. This study suggests that senomorphic drugs such as trametinib could be a useful adjunct to therapy for progeroid diseases.

Aging, Cellular Senescence, and Glaucoma

Aging is one of the most serious risk factors for glaucoma, and according to age-standardized prevalence, glaucoma is the second leading cause of legal blindness worldwide. Cellular senescence is a hallmark of aging that is defined by a stable exit from the cell cycle in response to cellular damage and stress. The potential mechanisms underlying glaucomatous cellular senescence include oxidative stress, DNA damage, mitochondrial dysfunction, defective autophagy/mitophagy, and epigenetic modifications. These phenotypes interact and generate a sufficiently stable network to maintain the cell senescent state. Senescent trabecular meshwork (TM) cells, retinal ganglion cells (RGCs) and vascular endothelial cells reportedly accumulate with age and stress and may contribute to glaucoma pathologies. Therapies targeting the suppression or elimination of senescent cells have been found to ameliorate RGC death and improve vision in glaucoma models, suggesting the pivotal role of cellular senescence in the pathophysiology of glaucoma. In this review, we explore the biological links between aging and glaucoma, specifically delving into cellular senescence. Moreover, we summarize the current data on cellular senescence in key target cells associated with the development and clinical phenotypes of glaucoma. Finally, we discuss the therapeutic potential of targeting cellular senescence for the management of glaucoma.

Subcellular structure, heterogeneity, and plasticity of senescent cells

Cellular senescence is a state of permanent growth arrest. It can be triggered by telomere shortening (replicative senescence) or prematurely induced by stresses such as DNA damage, oncogene overactivation, loss of tumor suppressor genes, oxidative stress, tissue factors, and others. Advances in techniques and experimental designs have provided new evidence about the biology of senescent cells (SnCs) and their importance in human health and disease. This review aims to describe the main aspects of SnCs phenotype focusing on alterations in subcellular compartments like plasma membrane, cytoskeleton, organelles, and nuclei. We also discuss the heterogeneity, dynamics, and plasticity of SnCs' phenotype, including the SASP, and pro-survival mechanisms. We advance on the multiple layers of phenotypic heterogeneity of SnCs, such as the heterogeneity between inducers, tissues and within a population of SnCs, discussing the relevance of these aspects to human health and disease. We also raise the main challenges as well alternatives to overcome them. Ultimately, we present open questions and perspectives in understanding the phenotype of SnCs from the perspective of basic and applied questions.

Senescence marker p16INK4a expression in patients with multiple sclerosis

OBJECTIVES

Telomere attrition is associated with disability accumulation and brain atrophy in multiple sclerosis (MS). Downstream of telomere attrition is cellular senescence. We sought to determine differences in the cellular senescence marker p16INK4a expression between MS and healthy control participants and the association of p16INK4a expression with MS disability and treatment exposure.

METHODS

Patients meeting diagnostic criteria for MS and healthy controls were recruited for a cross-sectional pilot study. RNA was extracted from peripheral blood mononuclear cells (PBMCs) and p16INK4a expression levels were measured using qRT PCR. Spearman correlation coefficients and regression models were applied to compare expression levels to chronological age, assess case control differences, and determine associations with clinical outcome measures.

RESULTS

Fifty-two participants with MS (67 % female, ages 25-70) and 38 healthy controls (66 % female, ages 23-65) were included. p16INK4a levels were not linearly correlated with chronological age in MS (rhos = -0.01, p = 0.94) or control participants (rhos = 0.02, p = 0.92). Higher median p16INK4a levels were observed in the >50-year age group for MS (0.25, IQR 0.14-0.35) vs. controls (0.12, IQR 0.05-0.15) and in this age group B cell depletion therapy was associated with lower expression levels. p16INK4a expression was not associated with any of the measured MS disability outcomes.

DISCUSSION

Caution is needed with using p16INK4a expression level from PBMCs as an aging biomarker in MS participants, given lack of correlation with chronological age or large associations with clinical outcomes.

Emerging therapeutic targets in systemic sclerosis

Systemic sclerosis is an autoimmune connective tissue disease which is characterised by vascular perturbations, inflammation, and fibrosis. Although huge progress recently into the underlying molecular pathways that are perturbed in the disease, currently no therapy exists that targets the fibrosis element of the disease and consequently there is a huge unmet medical need. Emerging studies reveal new dimensions of complexity, and multiple aberrant pathways have been uncovered that have shed light on disturbed signalling in the disease, primarily in inflammatory pathways that can be targeted with repurposed drugs. Pre-clinical animal models using these inhibitors have yielded proof of concept for targeting these signalling systems and progressing to clinical trials. This review will examine the recent evidence of new perturbed pathways in SSc and how these can be targeted with new or repurposed drugs to target a currently intractable disease.

Accelerated Aging Induced by an Unhealthy High-Fat Diet: Initial Evidence for the Role of Nrf2 Deficiency and Impaired Stress Resilience in Cellular Senescence

High-fat diets (HFDs) have pervaded modern dietary habits, characterized by their excessive saturated fat content and low nutritional value. Epidemiological studies have compellingly linked HFD consumption to obesity and the development of type 2 diabetes mellitus. Moreover, the synergistic interplay of HFD, obesity, and diabetes expedites the aging process and prematurely fosters age-related diseases. However, the underlying mechanisms driving these associations remain enigmatic. One of the most conspicuous hallmarks of aging is the accumulation of highly inflammatory senescent cells, with mounting evidence implicating increased cellular senescence in the pathogenesis of age-related diseases. Our hypothesis posits that HFD consumption amplifies senescence burden across multiple organs. To scrutinize this hypothesis, we subjected mice to a 6-month HFD regimen, assessing senescence biomarker expression in the liver, white adipose tissue, and the brain. Aging is intrinsically linked to impaired cellular stress resilience, driven by dysfunction in Nrf2-mediated cytoprotective pathways that safeguard cells against oxidative stress-induced senescence. To ascertain whether Nrf2-mediated pathways shield against senescence induction in response to HFD consumption, we explored senescence burden in a novel model of aging: Nrf2-deficient (Nrf2+/-) mice, emulating the aging phenotype. Our initial findings unveiled significant Nrf2 dysfunction in Nrf2+/- mice, mirroring aging-related alterations. HFD led to substantial obesity, hyperglycemia, and impaired insulin sensitivity in both Nrf2+/- and Nrf2+/+ mice. In control mice, HFD primarily heightened senescence burden in white adipose tissue, evidenced by increased Cdkn2a senescence biomarker expression. In Nrf2+/- mice, HFD elicited a significant surge in senescence burden across the liver, white adipose tissue, and the brain. We postulate that HFD-induced augmentation of senescence burden may be a pivotal contributor to accelerated organismal aging and the premature onset of age-related diseases.

The Senescent Heart-"Age Doth Wither Its Infinite Variety"

Cardiovascular diseases are a leading cause of morbidity and mortality world-wide. While many factors like smoking, hypertension, diabetes, dyslipidaemia, a sedentary lifestyle, and genetic factors can predispose to cardiovascular diseases, the natural process of aging is by itself a major determinant of the risk. Cardiac aging is marked by a conglomerate of cellular and molecular changes, exacerbated by age-driven decline in cardiac regeneration capacity. Although the phenotypes of cardiac aging are well characterised, the underlying molecular mechanisms are far less explored. Recent advances unequivocally link cardiovascular aging to the dysregulation of critical signalling pathways in cardiac fibroblasts, which compromises the critical role of these cells in maintaining the structural and functional integrity of the myocardium. Clearly, the identification of cardiac fibroblast-specific factors and mechanisms that regulate cardiac fibroblast function in the senescent myocardium is of immense importance. In this regard, recent studies show that Discoidin domain receptor 2 (DDR2), a collagen-activated receptor tyrosine kinase predominantly located in cardiac fibroblasts, has an obligate role in cardiac fibroblast function and cardiovascular fibrosis. Incisive studies on the molecular basis of cardiovascular aging and dysregulated fibroblast function in the senescent heart would pave the way for effective strategies to mitigate cardiovascular diseases in a rapidly growing elderly population.

Pulmonary Fibrosis and Diabetes Mellitus: Two coins with the same face

Idiopathic pulmonary fibrosis (IPF) constitutes a long-term disease with a complex pathophysiology composed of multiple molecular actors that lead to the deposition of extracellular matrix, the loss of pulmonary function and ultimately the patient's death. Despite the approval of pirfenidone and nintedanib for the treatment of the disease, lung transplant is the only long-term solution to fully recover the respiratory capacity and gain quality of life. One of the risk factors for the development of IPF is the pre-existing condition of diabetes mellitus. Both, IPF and diabetes mellitus, share similar pathological damage mechanisms, including inflammation, endoplasmic reticulum stress, mitochondrial failure, oxidative stress, senescence and signaling from glycated proteins through receptors. In this critical review article, we provide information about this interrelationship, examining molecular mediators that play an essential role in both diseases and identify targets of interest for the development of potential drugs. We review the findings of clinical trials examining the progression of IPF and how novel molecules may be used to stop this process. The results highlight the importance of early detection and addressing multiple therapeutic targets simultaneously to achieve better therapeutic efficacy and potentially reverse lung fibrosis.

Sophocarpine alleviates intestinal fibrosis via inhibition of inflammation and fibroblast into myofibroblast transition by targeting the Sirt1/p65 signaling axis

In this study, we used alkaloids from Sophora flavescens to inhibit the SASP, leading to fibroblast-into-myofibroblast transition (FMT) to maintain intestinal mucosal homeostasis in vitro and in vivo. We used western blotting (WB) and immunofluorescence staining (IF) to assess whether five kinds of alkaloids inhibit the major inflammatory pathways and chose the most effective compound (sophocarpine; SPC) to ameliorate colorectal inflammation in a dextran sulfate sodium (DSS)-induced UC mouse model. IF, Immunohistochemistry staining (IHC), WB, disease activity index (DAI), and enzyme-linked immunosorbent assay (ELISA) were conducted to investigate the mechanism of action of this compound. Next, we detected the pharmacological activity of SPC on the senescence-associated secretory phenotypes (SASP) and FMT in interleukin 6 (IL-6)-induced senescence-like fibroblasts and discussed the mucosal protection ability of SPC on a fibroblast-epithelium/organoid coculture system and organ-on-chip system. Taken together, our results provide evidence that SPC alleviates the inflammatory response, improves intestinal fibrosis and maintains intestinal mucosal homeostasis in vivo. Meanwhile, SPC was able to prevent IL-6-induced SASP and FMT in fibroblasts, maintain the expression of TJ proteins, and inhibit inflammation and genomic stability of colonic mucosal epithelial cells by activating SIRT1 in vitro. In conclusion, SPC treatment attenuates intestinal fibrosis by regulating SIRT1/NF-κB p65 signaling, and it might be a promising therapeutic agent for inflammatory bowel disease.

Chk2 Modulates Bmi1-Deficiency-Induced Renal Aging and Fibrosis via Oxidative Stress, DNA Damage, and p53/TGFβ1-Induced Epithelial-Mesenchymal Transition

Renal aging may lead to fibrosis and dysfunction, yet underlying mechanisms remain unclear. We explored whether deficiency of the Polycomb protein Bmi1 causes renal aging via DNA damage response (DDR) activation, inducing renal tubular epithelial cell (RTEC) senescence and epithelial-mesenchymal transition (EMT). Bmi1 knockout mice exhibited oxidative stress, DDR activation, RTEC senescence, senescence-associated secretory phenotype (SASP), and age-related fibrosis in kidneys. Bmi1 deficiency impaired renal structure and function, increasing serum creatinine/urea, reducing creatinine clearance, and decreasing cortical thickness and glomerular number. However, knockout of the serine-threonine kinase Chk2 alleviated these aging phenotypes. Transcriptomics identified transforming growth factor beta 1 (TGFβ1) upregulation in Bmi1-deficient RTECs, but TGFβ1 was downregulated upon Chk2 knockout. The tumor suppressor protein p53 transcriptionally activated TGFβ1, promoting EMT in RTECs. Bmi1 knockout or oxidative stress (induced with H2O2) increased TGFβ1 expression, and EMT in RTECs and was partly reversed by p53 inhibition. Together, Bmi1 deficiency causes oxidative stress and DDR-mediated RTEC senescence/SASP, thus activating p53 and TGFβ1 to induce EMT and age-related fibrosis. However, blocking DDR (via Chk2 knockout) or p53 ameliorates these changes. Our study reveals mechanisms whereby Bmi1 preserves renal structure and function during aging by suppressing DDR and p53/TGFβ1-mediated EMT. These pathways represent potential targets for detecting and attenuating age-related renal decline.

Resolvin D1 suppresses macrophage senescence and splenic fibrosis in aged mice

Aging is associated with systemic, non-resolving inflammation and the accumulation of senescent cells. The resolution of inflammation (or inflammation-resolution) is in part mediated by the balance between specialized pro-resolving mediators (SPMs) and pro-inflammatory leukotrienes (LTs). Aged mice (i.e. 2 years of age) exhibit a significant decrease in the SPM:LT ratio in specific organs including the spleen, which suggests that this organ may exhibit heightened inflammation and may be particularly amenable to SPM therapy. Previous studies have shown that resolvin D1 (RvD1) is decreased in spleens of aged mice compared with young controls. Therefore, we asked whether treatment of RvD1 in aged mice would impact markers of cellular senescence in splenic macrophages, and downstream effects on splenic fibrosis, a hallmark of splenic aging. We found that in aged mice, both zymosan-elicited and splenic macrophages showed an increase in mRNA expression of inflammatory and eicosanoid biosynthesis genes and a dysregulation of genes involved in the cell cycle. Injections with RvD1 reversed these changes. Importantly, RvD1 also decreased splenic fibrosis, a hallmark of splenic aging. Our findings suggest that RvD1 treatment may limit several features of aging, including senescence and fibrosis in spleens from aged mice. Summary Aging is associated with systemic, low grade, non-resolving inflammation. The resolution of inflammation is in part mediated by the balance between specialized pro-resolving mediators (SPMs) and pro-inflammatory lipid mediators, like leukotrienes (LTs). A hallmark of aging is the accumulation of senescent cells that promote low grade inflammation by secreting pro-inflammatory cytokines and lipid mediators. Splenic macrophages contribute to systemic aging, and spleens of aged mice demonstrate decreased levels of the SPM called resolvin D1 (RvD1). Whether addition of RvD1 is protective in spleens of aged mice is unknown and is focus of this study. RvD1 treatment to aged mice led to decreased mRNA expression of markers of cellular senescence and inflammation in splenic macrophages compared with age-matched vehicle controls. Moreover, RvD1 decreased splenic fibrosis, which occurs due to persistent low-grade inflammation in aging. Promoting inflammation resolution with RvD1 thus limits macrophage senescence, pro-inflammatory signals and established splenic fibrosis in aging.

Essential oil from Fructus Alpiniae zerumbet ameliorates vascular endothelial cell senescence in diabetes by regulating PPAR-γ signalling: A 4D label-free quantitative proteomics and network pharmacology study

ETHNOPHARMACOLOGICAL RELEVANCE

Vascular endothelial cell senescence is associated with cardiovascular complications in diabetes. Essential oil from Fructus Alpiniae zerumbet (Pers.) B.L.Burtt & R.M.Sm. (EOFAZ) has potentially beneficial and promising diabetes-related vascular endothelial cell senescence-mitigating effects; however, the underlying molecular mechanisms remain unclear.

AIM OF THE STUDY

To investigate the molecular effects of EOFAZ on vascular endothelial cell senescence in diabetes.

MATERIALS AND METHODS

A diabetes mouse model was developed using a high-fat and high-glucose diet (HFD) combined with intraperitoneal injection of low-dose streptozotocin (STZ, 30 mg/kg) and oral treatment with EOFAZ. 4D label-free quantitative proteomics, network pharmacology, and molecular docking techniques were employed to explore the molecular mechanisms via which EOFAZ alleviates diabetes-related vascular endothelial cell senescence. A human aortic endothelial cells (HAECs) senescence model was developed using high palmitic acid and high glucose (PA/HG) concentrations in vitro. Western blotting, immunofluorescence, SA-β-galactosidase staining, cell cycle, reactive oxygen species (ROS), cell migration, and enzyme linked immunosorbent assays were performed to determine the protective role of EOFAZ against vascular endothelial cell senescence in diabetes. Moreover, the PPAR-γ agonist rosiglitazone, inhibitor GW9662, and siRNA were used to verify the underlying mechanism by which EOFAZ combats vascular endothelial cell senescence in diabetes.

RESULTS

EOFAZ treatment ameliorated abnormal lipid metabolism, vascular histopathological damage, and vascular endothelial aging in diabetic mice. Proteomics and network pharmacology analysis revealed that the differentially expressed proteins (DEPs) and drug-disease targets were associated with the peroxisome proliferator-activated receptor gamma (PPAR-γ) signalling pathway, a key player in vascular endothelial cell senescence. Molecular docking indicated that the small-molecule compounds in EOFAZ had a high affinity for the PPAR-γ protein. Western blotting and immunofluorescence analyses confirmed the significance of DEPs and the involvement of the PPAR-γ signalling pathway. In vitro, EOFAZ and rosiglitazone treatment reversed the effects of PA/HG on the number of senescent endothelial cells, expression of senescence-related proteins, the proportion of cells in the G0/G1 phase, ROS levels, cell migration rate, and expression of pro-inflammatory factors. The protective effects of EOFAZ against vascular endothelial cell senescence in diabetes were aborted following treatment with GW9662 or PPAR-γ siRNA.

CONCLUSIONS

EOFAZ ameliorates vascular endothelial cell senescence in diabetes by activating PPAR-γ signalling. The results of the present study highlight the potential beneficial and promising therapeutic effects of EOFAZ and provide a basis for its clinical application in diabetes-related vascular endothelial cell senescence.

Immunomodulatory Effects of Histone Variant H2A.J in Ionizing Radiation Dermatitis

PURPOSE

Histone variant H2A.J is associated with premature senescence after ionizing radiation (IR) and modulates senescence-associated secretory phenotype (SASP). Using constitutive H2A.J knock-out mice, the role of H2A.J was investigated in radiation dermatitis.

METHODS AND MATERIALS

H2A.J wild-type (WT) and knock-out (KO) mice were exposed to moderate or high IR doses (≤20 Gy, skinfold IR). Radiation-induced skin reactions were investigated up to 2 weeks post-IR at macroscopic and microscopic levels. H2A.J and other senescence markers, as well as DNA damage and proliferation markers, were studied by immunohistochemistry, immunofluorescence, and electron microscopy. After high-dose IR, protein-coding transcriptomes were analyzed by RNA sequencing, immune cell infiltration by flow cytometry, and gene expression by reverse transcription polymerase chain reaction in (non-) irradiated WT versus KO skin.

RESULTS

In WT skin, epidermal keratinocytes showed time- and dose-dependent H2A.J accumulation after IR exposure. Unexpectedly, stronger inflammatory reactions with increased epidermal thickness and progressive hair follicle loss were observed in irradiated KO versus WT skin. Clearly more radiation-induced senescence was observed in keratinocyte populations of KO skin after moderate and high doses, with hair follicle stem cells being particularly badly damaged, leading to follicle atrophy. After high-dose IR, transcriptomic analysis revealed enhanced senescence-associated signatures in irradiated KO skin, with intensified release of SASP factors. Flow cytometric analysis indicated increased immune cell infiltration in both WT and KO skin; however, specific chemokine-mediated signaling in irradiated KO skin led to more neutrophil recruitment, thereby aggravating radiation toxicities. Increased skin damage in irradiated KO skin led to hyperproliferation, abnormal differentiation, and cornification of keratinocytes, accompanied by increased upregulation of transcription-factor JunB.

CONCLUSIONS

Lack of radiation-induced H2A.J expression in keratinocytes is associated with increased senescence induction, modulation of SASP expression, and exacerbated inflammatory skin reactions. Hence, epigenetic H2A.J-mediated gene expression in response to IR regulates keratinocyte immune functions and plays an essential role in balancing the inflammatory response during radiation dermatitis.

Recent advances in senescence-associated secretory phenotype and osteoporosis

The worldwide elderly population is on the rise, and aging is a major osteoporosis risk factor. Senescent cells accumulation can have a detrimental effect the body as we age. The senescence-associated secretory phenotype (SASP), an essential cellular senescence hallmark, is an important mechanism connecting cellular senescence to osteoporosis. This review describes in detail the characteristics of SASPs and their regulatory agencies, and shed fresh light on how SASPs from different senescent cells contribute to osteoporosis development. Furthermore, we summarized various innovative therapy techniques that target SASPs to lower the burden of osteoporosis in the elderly and discussed the potential challenges of SASPs-based therapy for osteoporosis as a new clinical trial.

Reactive gliosis in traumatic brain injury: a comprehensive review

Traumatic brain injury (TBI) is one of the most common pathological conditions impacting the central nervous system (CNS). A neurological deficit associated with TBI results from a complex of pathogenetic mechanisms including glutamate excitotoxicity, inflammation, demyelination, programmed cell death, or the development of edema. The critical components contributing to CNS response, damage control, and regeneration after TBI are glial cells-in reaction to tissue damage, their activation, hypertrophy, and proliferation occur, followed by the formation of a glial scar. The glial scar creates a barrier in damaged tissue and helps protect the CNS in the acute phase post-injury. However, this process prevents complete tissue recovery in the late/chronic phase by producing permanent scarring, which significantly impacts brain function. Various glial cell types participate in the scar formation, but this process is mostly attributed to reactive astrocytes and microglia, which play important roles in several brain pathologies. Novel technologies including whole-genome transcriptomic and epigenomic analyses, and unbiased proteomics, show that both astrocytes and microglia represent groups of heterogenic cell subpopulations with different genomic and functional characteristics, that are responsible for their role in neurodegeneration, neuroprotection and regeneration. Depending on the representation of distinct glia subpopulations, the tissue damage as well as the regenerative processes or delayed neurodegeneration after TBI may thus differ in nearby or remote areas or in different brain structures. This review summarizes TBI as a complex process, where the resultant effect is severity-, region- and time-dependent and determined by the model of the CNS injury and the distance of the explored area from the lesion site. Here, we also discuss findings concerning intercellular signaling, long-term impacts of TBI and the possibilities of novel therapeutical approaches. We believe that a comprehensive study with an emphasis on glial cells, involved in tissue post-injury processes, may be helpful for further research of TBI and be the decisive factor when choosing a TBI model.

Targeting Cellular Senescence in Aging and Age-Related Diseases: Challenges, Considerations, and the Emerging Role of Senolytic and Senomorphic Therapies

Cellular senescence is characterized by the permanent arrest of cell proliferation and is a response to endogenous and exogenous stress. The continuous accumulation of senescent cells (SnCs) in the body leads to the development of aging and age-related diseases (such as neurodegenerative diseases, cancer, metabolic diseases, cardiovascular diseases, and osteoarthritis). In the face of the growing challenge of aging and age-related diseases, several compounds have received widespread attention for their potential to target SnCs. As a result, senolytics (compounds that selectively eliminate SnCs) and senomorphics (compounds that alter intercellular communication and modulate the behavior of SnCs) have become hot research topics in the field of anti-aging. In addition, strategies such as combination therapies and immune-based approaches have also made significant progress in the field of anti-aging therapy. In this article, we discuss the latest research on anti-aging targeting SnCs and gain a deeper understanding of the mechanism of action and impact of different anti-aging strategies on aging and age-related diseases, with the aim of providing more effective references and therapeutic ideas for clinical anti-aging treatment in the face of the ever-grave challenges of aging and age-related diseases.

Geroscience and pathology: a new frontier in understanding age-related diseases

Geroscience, a burgeoning discipline at the intersection of aging and disease, aims to unravel the intricate relationship between the aging process and pathogenesis of age-related diseases. This paper explores the pivotal role played by geroscience in reshaping our understanding of pathology, with a particular focus on age-related diseases. These diseases, spanning cardiovascular and cerebrovascular disorders, malignancies, and neurodegenerative conditions, significantly contribute to the morbidity and mortality of older individuals. We delve into the fundamental cellular and molecular mechanisms underpinning aging, including mitochondrial dysfunction and cellular senescence, and elucidate their profound implications for the pathogenesis of various age-related diseases. Emphasis is placed on the importance of assessing key biomarkers of aging and biological age within the realm of pathology. We also scrutinize the interplay between cellular senescence and cancer biology as a central area of focus, underscoring its paramount significance in contemporary pathological research. Moreover, we shed light on the integration of anti-aging interventions that target fundamental aging processes, such as senolytics, mitochondria-targeted treatments, and interventions that influence epigenetic regulation within the domain of pathology research. In conclusion, the integration of geroscience concepts into pathological research heralds a transformative paradigm shift in our understanding of disease pathogenesis and promises breakthroughs in disease prevention and treatment.

Exploring the effects of Dasatinib, Quercetin, and Fisetin on DNA methylation clocks: a longitudinal study on senolytic interventions

Senolytics, small molecules targeting cellular senescence, have emerged as potential therapeutics to enhance health span. However, their impact on epigenetic age remains unstudied. This study aimed to assess the effects of Dasatinib and Quercetin (DQ) senolytic treatment on DNA methylation (DNAm), epigenetic age, and immune cell subsets. In a Phase I pilot study, 19 participants received DQ for 6 months, with DNAm measured at baseline, 3 months, and 6 months. Significant increases in epigenetic age acceleration were observed in first-generation epigenetic clocks and mitotic clocks at 3 and 6 months, along with a notable decrease in telomere length. However, no significant differences were observed in second and third-generation clocks. Building upon these findings, a subsequent investigation evaluated the combination of DQ with Fisetin (DQF), a well-known antioxidant and antiaging senolytic molecule. After one year, 19 participants (including 10 from the initial study) received DQF for 6 months, with DNAm assessed at baseline and 6 months. Remarkably, the addition of Fisetin to the treatment resulted in non-significant increases in epigenetic age acceleration, suggesting a potential mitigating effect of Fisetin on the impact of DQ on epigenetic aging. Furthermore, our analyses unveiled notable differences in immune cell proportions between the DQ and DQF treatment groups, providing a biological basis for the divergent patterns observed in the evolution of epigenetic clocks. These findings warrant further research to validate and comprehensively understand the implications of these combined interventions.

Potential Clinical Implications of Senotherapies for Cardiovascular Disease

Aging is a major risk factor for cardiovascular diseases (CVDs) and accumulating evidence indicates that biological aging has a significant effect on the onset and progression of CVDs. In recent years, therapies targeting senescent cells (senotherapies), particularly senolytics that selectively eliminate senescent cells, have been developed and show promise for treating geriatric syndromes and age-associated diseases, including CVDs. In 2 pilot studies published in 2019 the senolytic combination, dasatinib plus quercetin, improved physical function in patients with idiopathic pulmonary fibrosis and eliminated senescent cells from adipose tissue in patients with diabetic kidney disease. More than 30 clinical trials using senolytics are currently underway or planned. In preclinical CVD models, senolytics appear to improve heart failure, ischemic heart disease, valvular heart disease, atherosclerosis, aortic aneurysm, vascular dysfunction, dialysis arteriovenous fistula patency, and pre-eclampsia. Because senotherapies are completely different strategies from existing treatment paradigms, they might alleviate diseases for which there are no current effective treatments or they could be used in addition to current therapies to enhance efficacy. Moreover, senotherapies might delay, prevent, alleviate or treat multiple diseases in the elderly and reduce polypharmacy, because senotherapies target fundamental aging mechanisms. We comprehensively summarize the preclinical evidence about senotherapies for CVDs and discuss future prospects for their clinical application.

Vascular Regenerative Cell Deficiencies in South Asian Adults

BACKGROUND

South Asian individuals shoulder a disproportionate burden of cardiometabolic diseases.

OBJECTIVES

The purpose of this study was to determine if vascular regenerative cell content varies significantly between South Asian and White European people.

METHODS

Between January 2022 and January 2023, 60 South Asian and 60 White European adults with either documented cardiovascular disease or established diabetes with ≥1 other cardiovascular risk factor were prospectively enrolled. Vascular regenerative cell content in venous blood was enumerated using a flow cytometry assay that is based on high aldehyde dehydrogenase (ALDHhi) activity and cell surface marker phenotyping. The primary outcome was the difference in frequency of circulating ALDHhi progenitor cells, monocytes, and granulocytes between the 2 groups.

RESULTS

Compared with White European participants, those of South Asian ethnicity were younger (69 ± 10 years vs 66 ± 9 years; P < 0.05), had lower weight (88 ± 19 kg vs 75 ± 13 kg; P < 0.001), and exhibited a greater prevalence of type 2 diabetes (62% vs 92%). South Asian individuals had markedly lower circulating frequencies of pro-angiogenic ALDHhiSSClowCD133+ progenitor cells (P < 0.001) and ALDHhiSSCmidCD14+CD163+ monocytes with vessel-reparative capacity (P < 0.001), as well as proportionally more ALDHhi progenitor cells with high reactive oxygen species content (P < 0.05). After correction for sex, age, body mass index, and glycated hemoglobin, South Asian ethnicity was independently associated with lower ALDHhiSSClowCD133+ cell count.

CONCLUSIONS

South Asian people with cardiometabolic disease had less vascular regenerative and reparative cells suggesting compromised vessel repair capabilities that may contribute to the excess vascular risk in this population. (The Role of South Asian vs European Origins on Circulating Regenerative Cell Exhaustion [ORIGINS-RCE]; NCT05253521).

Therapy-Induced Senescence Contributes to the Efficacy of Abemaciclib in Patients with Dedifferentiated Liposarcoma

PURPOSE

We conducted research on CDK4/6 inhibitors (CDK4/6i) simultaneously in the preclinical and clinical spaces to gain a deeper understanding of how senescence influences tumor growth in humans.

PATIENTS AND METHODS

We coordinated a first-in-kind phase II clinical trial of the CDK4/6i abemaciclib for patients with progressive dedifferentiated liposarcoma (DDLS) with cellular studies interrogating the molecular basis of geroconversion.

RESULTS

Thirty patients with progressing DDLS enrolled and were treated with 200 mg of abemaciclib twice daily. The median progression-free survival was 33 weeks at the time of the data lock, with 23 of 30 progression-free at 12 weeks (76.7%, two-sided 95% CI, 57.7%-90.1%). No new safety signals were identified. Concurrent preclinical work in liposarcoma cell lines identified ANGPTL4 as a necessary late regulator of geroconversion, the pathway from reversible cell-cycle exit to a stably arrested inflammation-provoking senescent cell. Using this insight, we were able to identify patients in which abemaciclib induced tumor cell senescence. Senescence correlated with increased leukocyte infiltration, primarily CD4-positive cells, within a month of therapy. However, those individuals with both senescence and increased TILs were also more likely to acquire resistance later in therapy. These suggest that combining senolytics with abemaciclib in a subset of patients may improve the duration of response.

CONCLUSIONS

Abemaciclib was well tolerated and showed promising activity in DDLS. The discovery of ANGPTL4 as a late regulator of geroconversion helped to define how CDK4/6i-induced cellular senescence modulates the immune tumor microenvironment and contributes to both positive and negative clinical outcomes. See related commentary by Weiss et al., p. 649.

Association between Gut Microbiota and Biological Aging: A Two-Sample Mendelian Randomization Study

Recent observational studies revealed an association between gut microbiota and aging, but whether gut microbiota are causally associated with the aging process remains unknown. We used a two-sample Mendelian randomization approach to investigate the causal association between gut microbiota and biological age acceleration using the largest available gut microbiota GWAS summary data from the MiBioGen consortium and GWAS data on biological age acceleration. We further conducted sensitivity analysis using MR-PRESSO, MR-Egger regression, Cochran Q test, and reverse MR analysis. Streptococcus (IVW, β = 0.16, p = 0.0001) was causally associated with Bioage acceleration. Eubacterium (rectale group) (IVW, β = 0.20, p = 0.0190), Sellimonas (IVW, β = 0.06, p = 0.019), and Lachnospira (IVW, β = -0.18, p = 0.01) were suggestive of causal associations with Bioage acceleration, with the latter being protective. Actinomyces (IVW, β = 0.26, p = 0.0083), Butyricimonas (IVW, β = 0.21, p = 0.0184), and Lachnospiraceae (FCS020 group) (IVW, β = 0.24, p = 0.0194) were suggestive of causal associations with Phenoage acceleration. This Mendelian randomization study found that Streptococcus was causally associated with Bioage acceleration. Further randomized controlled trials are needed to investigate its role in the aging process.

Magnesium and the Hallmarks of Aging

Magnesium is an essential ion in the human body that regulates numerous physiological and pathological processes. Magnesium deficiency is very common in old age. Age-related chronic diseases and the aging process itself are frequently associated with low-grade chronic inflammation, called 'inflammaging'. Because chronic magnesium insufficiency has been linked to excessive generation of inflammatory markers and free radicals, inducing a chronic inflammatory state, we formerly hypothesized that magnesium inadequacy may be considered among the intermediaries helping us explain the link between inflammaging and aging-associated diseases. We show in this review evidence of the relationship of magnesium with all the hallmarks of aging (genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication, disabled autophagy, dysbiosis, and chronic inflammation), which may positively affect the human healthspan. It is feasible to hypothesize that maintaining an optimal balance of magnesium during one's life course may turn out to be a safe and economical strategy contributing to the promotion of healthy aging. Future well-designed studies are necessary to further explore this hypothesis.

Osteochondroprogenitor cells and neutrophils expressing p21 and senescence markers modulate fracture repair

Cells expressing features of senescence, including upregulation of p21 and p16, appear transiently following tissue injury, yet the properties of these cells or how they contrast with age-induced senescent cells remains unclear. Here, we used skeletal injury as a model and identified the rapid appearance following fracture of p21+ cells expressing senescence markers, mainly as osteochondroprogenitors (OCHs) and neutrophils. Targeted genetic clearance of p21+ cells suppressed senescence-associated signatures within the fracture callus and accelerated fracture healing. By contrast, p21+ cell clearance did not alter bone loss due to aging; conversely, p16+ cell clearance, known to alleviate skeletal aging, did not affect fracture healing. Following fracture, p21+ neutrophils were enriched in signaling pathways known to induce paracrine stromal senescence, while p21+ OCHs were highly enriched in senescence-associated secretory phenotype factors known to impair bone formation. Further analysis revealed an injury-specific stem cell-like OCH subset that was p21+ and highly inflammatory, with a similar inflammatory mesenchymal population (fibro-adipogenic progenitors) evident following muscle injury. Thus, intercommunicating senescent-like neutrophils and mesenchymal progenitor cells are key regulators of tissue repair in bone and potentially across tissues. Moreover, our findings establish contextual roles of p21+ vs p16+ senescent/senescent-like cells that may be leveraged for therapeutic opportunities.

Inhibiting Glutaminase Exerts Opposite Effects on Ovariectomy-Induced and Age-Related Reductions in Murine Bone Mass

Recent studies have provided links between glutamine metabolism and bone remodeling, but little is known about its role in primary osteoporosis progression. We aimed to determine the effects of inhibiting glutaminase (GLS) on two types of primary osteoporosis and elucidate the related metabolism. To address this issue, age-related and ovariectomy (OVX)-induced bone loss mouse models were used to study the in vivo effects of CB-839, a potent and selective GLS inhibitor, on bone mass and bone turnover. We also studied the metabolic profile changes related with aging and GLS inhibition in primary bone marrow stromal cells (BMSC) and that related with OVX and GLS inhibition in primary bone marrow-derived monocytes (BMM). Besides, we studied the possible metabolic processes mediating GLS blockade effects during aging-impaired osteogenic differentiation and RANKL-induced osteoclast differentiation respectively via in vitro rescue experiments. We found that inhibiting GLS via CB-839 prevented OVX-induced bone loss while aggravated age-related bone loss. Further investigations showed that effects of CB-839 treatment on bone mass were associated with alterations of bone turnover. Moreover, CB-839 treatment altered metabolic profile in different orientations between BMSC of aged mice and BMM of ovariectomized mice. In addition, rescue experiments revealed that different metabolic processes mediated glutaminase blockade effects between aging-impaired osteogenic differentiation and RANKL-induced osteoclast differentiation. Taken together, our data demonstrated the different outcomes caused by CB-839 treatment between two types of osteoporosis in mice, which were tightly connected to the suppressive effects on both aging-impaired osteoblastogenesis and OVX-enhanced osteoclastogenesis mediated by different metabolic processes downstream of glutaminolysis.

Heat shock response during the resolution of inflammation and its progressive suppression in chronic-degenerative inflammatory diseases

The heat shock response (HSR) is a crucial biochemical pathway that orchestrates the resolution of inflammation, primarily under proteotoxic stress conditions. This process hinges on the upregulation of heat shock proteins (HSPs) and other chaperones, notably the 70 kDa family of heat shock proteins, under the command of the heat shock transcription factor-1. However, in the context of chronic degenerative disorders characterized by persistent low-grade inflammation (such as insulin resistance, obesity, type 2 diabetes, nonalcoholic fatty liver disease, and cardiovascular diseases) a gradual suppression of the HSR does occur. This work delves into the mechanisms behind this phenomenon. It explores how the Western diet and sedentary lifestyle, culminating in the endoplasmic reticulum stress within adipose tissue cells, trigger a cascade of events. This cascade includes the unfolded protein response and activation of the NOD-like receptor pyrin domain-containing protein-3 inflammasome, leading to the emergence of the senescence-associated secretory phenotype and the propagation of inflammation throughout the body. Notably, the activation of the NOD-like receptor pyrin domain-containing protein-3 inflammasome not only fuels inflammation but also sabotages the HSR by degrading human antigen R, a crucial mRNA-binding protein responsible for maintaining heat shock transcription factor-1 mRNA expression and stability on heat shock gene promoters. This paper underscores the imperative need to comprehend how chronic inflammation stifles the HSR and the clinical significance of evaluating the HSR using cost-effective and accessible tools. Such understanding is pivotal in the development of innovative strategies aimed at the prevention and treatment of these chronic inflammatory ailments, which continue to take a heavy toll on global health and well-being.

2'-O-ribose methylation levels of ribosomal RNA distinguish different types of growth arrest in human dermal fibroblasts

The 2'-O-methylation (2'-O-Me) of ribosomal RNA (rRNA) shows plasticity that is potentially associated with cell phenotypes. We used RiboMeth-seq profiling to reveal growth arrest-specific 2'-O-Me patterns in primary human dermal fibroblasts from three different donors. We exposed cells to hydrogen peroxide to induce cellular senescence and to high cell densities to promote quiescence by contact inhibition. We compared both modes of cell cycle arrest to proliferating cells and could indeed distinguish these conditions by their overall 2'-O-Me patterns. Methylation levels at a small fraction of sites showed plasticity and correlated with the expression of specific small nucleolar RNAs (snoRNAs) but not with expression of fibrillarin. Moreover, we observed subtle senescence-associated alterations in ribosome biogenesis. Knockdown of the snoRNA SNORD87, which acts as a guide for modification of a hypermethylated position in non-proliferating cells, was sufficient to boost cell proliferation. Conversely, depletion of SNORD88A, SNORD88B and SNORD88C, which act as guides for modification of a hypomethylated site, caused decreased proliferation without affecting global protein synthesis or apoptosis. Taken together, our findings provide evidence that rRNA modifications can be used to distinguish and potentially influence specific growth phenotypes of primary cells.

Past and Future Directions for Research on Cellular Senescence

Cellular senescence was initially described in the early 1960s by Hayflick and Moorehead. They noted sustained cell-cycle arrest after repeated subculturing of human primary cells. Over half a century later, cellular senescence has become recognized as one of the fundamental pillars of aging. Developing senotherapeutics, interventions that selectively eliminate or target senescent cells, has emerged as a key focus in health research. In this article, we note major milestones in cellular senescence research, discuss current challenges, and point to future directions for this rapidly growing field.

Biomimetic Therapeutics for Bone Regeneration: A Perspective on Antiaging Strategies

Advances in modern medicine and the significant reduction in infant mortality have steadily increased the population's lifespan. As more and more people in the world grow older, incidence of chronic, noncommunicable disease is anticipated to drastically increase. Recent studies have shown that improving the health of the aging population is anticipated to provide the most cost-effective and impactful improvement in quality of life during aging-driven disease. In bone, aging is tightly linked to increased risk of fracture, and markedly decreased regenerative potential, deeming it critical to develop therapeutics to improve aging-driven bone regeneration. Biomimetics offer a cost-effective method in regenerative therapeutics for bone, where there are numerous innovations improving outcomes in young models, but adapting biomimetics to aged models is still a challenge. Chronic inflammation, accumulation of reactive oxygen species, and cellular senescence are among three of the more unique challenges facing aging-induced defect repair. This review dissects many of the innovative biomimetic approaches research groups have taken to tackle these challenges, and discusses the further uncertainties that need to be addressed to push the field further. Through these research innovations, it can be noted that biomimetic therapeutics hold great potential for the future of aging-complicated defect repair.

Clinical and Treatment Considerations for the Pediatric and Aging Patients with Multiple Sclerosis

Chronologic aging is associated with multiple pathologic and immunologic changes that impact the clinical course of multiple sclerosis (MS). Clinical phenotypes evolve across the lifespan, from a highly inflammatory course in the very young to a predominantly neurodegenerative phenotype in older patients. Thus, unique clinical considerations arise for the diagnosis and management of the two age extremes of pediatric and geriatric MS populations. This review covers epidemiology, diagnosis, and treatment strategies for these populations with nuanced discussions on therapeutic approaches to effectively care for patients living with MS at critical transition points during their lifespan.

Mapping cellular senescence networks in human diabetic foot ulcers

Cellular senescence, a cell fate defined by irreversible cell cycle arrest, has been observed to contribute to chronic age-related conditions including non-healing wounds, such as diabetic foot ulcers. However, the role of cellular senescence in the pathogenesis of diabetic foot ulcers remains unclear. To examine the contribution of senescent phenotypes to these chronic wounds, differential gene and network analyses were performed on publicly available bulk RNA sequencing of whole skin biopsies of wound edge diabetic foot ulcers and uninvolved diabetic foot skin. Wald tests with Benjamini-Hochberg correction were used to evaluate differential gene expression. Results showed that cellular senescence markers, CDKN1A, CXCL8, IGFBP2, IL1A, MMP10, SERPINE1, and TGFA, were upregulated, while TP53 was downregulated in diabetic foot ulcers compared to uninvolved diabetic foot skin. NetDecoder was then used to identify and compare context-specific protein-protein interaction networks using known cellular senescence markers as pathway sources. The diabetic foot ulcer protein-protein interaction network demonstrated significant perturbations with decreased inhibitory interactions and increased senescence markers compared to uninvolved diabetic foot skin. Indeed, TP53 (p53) and CDKN1A (p21) appeared to be key regulators in diabetic foot ulcer formation. These findings suggest that cellular senescence is an important mediator of diabetic foot ulcer pathogenesis.

Repression of YEATS2 induces cellular senescence in hepatocellular carcinoma and inhibits tumor growth

Hepatocellular carcinoma (HCC) stands as the third leading cause of cancer-related fatalities globally. In this study, we observed a significant increase in the expression level of the YEATS2 gene in HCC patients, and it is negatively correlated with the patients' survival rate. While we have previously identified the association between YEATS2 and the survival of pancreatic cancer cells, the regulatory mechanisms and significance in HCC are still to be fully elucidated. Our study shows that knockdown (KD) of YEATS2 expression leads to DNA damage, which in turn results in an upregulation of γ-H2A.X expression and activation of the canonical senescence-related pathway p53/p21Cip1. Moreover, our transcriptomic analysis reveals that YEATS2 KD cells can enhance the expression of p21Cip1 via the c-Myc/miR-93-5p pathway, consequently fostering the senescence of HCC cells. The initiation of cellular senescence through dual-channel activation suggests that YEATS2 plays a pivotal regulatory role in the process of cell proliferation. Ultimately, our in vivo research utilizing a nude mouse tumor model revealed a notable decrease in both tumor volume and weight after the suppression of YEATS2 expression. This phenomenon is likely attributable to the attenuation of proliferative cell activity, coupled with a concurrent augmentation in the population of natural killer (NK) cells. In summary, our research results have supplemented the understanding of the regulatory mechanisms of HCC cell proliferation and indicated that targeting YEATS2 may potentially inhibit liver tumor growth.

Age-related bone diseases: Role of inflammaging

Bone aging is characterized by an imbalance in the physiological and pathological processes of osteogenesis, osteoclastogenesis, adipogenesis, and chondrogenesis, resulting in exacerbated bone loss and the development of age-related bone diseases, including osteoporosis, osteoarthritis, rheumatoid arthritis, and periodontitis. Inflammaging, a novel concept in the field of aging research, pertains to the persistent and gradual escalation of pro-inflammatory reactions during the aging process. This phenomenon is distinguished by its low intensity, systemic nature, absence of symptoms, and potential for management. The mechanisms by which inflammaging contribute to age-related chronic diseases, particularly in the context of age-related bone diseases, remain unclear. The precise manner in which systemic inflammation induces bone aging and consequently contributes to the development of age-related bone diseases has yet to be fully elucidated. This article primarily examines the mechanisms underlying inflammaging and its association with age-related bone diseases, to elucidate the potential mechanisms of inflammaging in age-related bone diseases and offer insights for developing preventive and therapeutic strategies for such conditions.

The relationship between self-perceived fatigue, muscle endurance, and circulating markers of inflammation in participants of the Copenhagen aging and Midlife Biobank (CAMB)

BACKGROUND

Fatigue, low muscle endurance, muscle weakness and low-grade inflammation are strongly related to frailty at higher age. When signs of self-perceived fatigue and low muscle endurance are interrelated with low-grade inflammation at midlife, they might be used as early markers for frailty. This study investigated whether the interrelationships among self-perceived fatigue, muscle endurance and inflammation can be observed at midlife.

METHODS

A total of 965 participants of the Copenhagen Aging and Midlife Biobank (aged 52 ± 4 years, 536 males, 426 females) were assessed for self-perceived fatigue (20-item multidimensional fatigue inventory), muscle endurance (grip work), circulating markers of inflammation (hsCRP, IL-6, IL-10, TNF-alpha and IFN-γ), daily physical activity (PAS-2), body composition (%body fat assessed by bio-impedance) and self-reported health status. Participants were categorised (correcting for age and gender) according to high fatigue and/or low muscle endurance, differences in inflammatory profile between fatigue categories were assessed by ANCOVA (corrected for PAS-2, %body fat and presence of inflammatory conditions).

RESULTS

Overall, muscle endurance, fatigue and inflammatory markers were significantly interrelated. Higher levels of hsCRP (p < 0.001), IL-6 (p < 0.001), IL-10 (p = 0.035) and TNF-alpha (p = 0.028) were observed in participants presenting both low muscle endurance and high fatigue. IFN-γ was highest in those with high fatigue but normal muscle endurance (p = 0.015).

CONCLUSIONS

Middle-aged participants with higher fatigue in combination with low muscle endurance show higher levels of inflammation, independently from physical activity, body fat and inflammatory pathology. The underlying mechanisms should be identified and future studies should also investigate whether these individuals show early signs of reduced physiological reserve capacity, which in later life come to full expression by means of frailty.

Bioinformatics reveals the pathophysiological relationship between diabetic nephropathy and periodontitis in the context of aging

Diabetic nephropathy (DN) is one of the most common microvascular complications of diabetes mellitus. Periodontitis (PD) is a microbially-induced chronic inflammatory disease that is thought to have a bidirectional relationship with diabetes mellitus. DN and PD are recognized as models associated with accelerated aging. This study is divided into two parts, the first of which explores the bidirectional causal relationship through Mendelian randomization (MR). The second part aims to investigate the relationship between PD and DN in terms of potential crosstalk genes, aging-related genes, biological pathways, and processes using bioinformatic methods. MR analysis showed no evidence to support a causal relationship between DN and PD (P = 0.34) or PD and DN (P = 0.77). Using the GEO database, we screened 83 crosstalk genes overlapping in two diseases. Twelve paired genes identified by Pearson correlation and the four hub genes in the key cluster were jointly evaluated as key crosstalk-aging genes. Using support vector machine recursive feature elimination (SVM-RFE) and maximal clique centrality (MCC) algorithms, feature selection established five genes as the key crosstalk-aging genes. Based on five key genes, an ANN diagnostic model with reliable diagnosis of two diseases was developed. Gene enrichment analysis indicates that AGE-RAGE pathway signaling, the complement system, and multiple immune inflammatory pathways may be involved in common features of both diseases. Immune infiltration analysis reveals that most immune cells are differentially expressed in PD and DN, with dendritic cells and T cells assuming vital roles in both diseases. Overall, although there is no causal link, CSF1R, CXCL6, VCAM1, JUN and IL1B may be potential crosstalk-aging genes linking PD and DN. The common pathways and markers explored in this study could contribute to a deeper understanding of the common pathogenesis of both diseases in the context of aging and provide a theoretical basis for future research.

Identification of Senescence-Associated Biomarkers in Diabetic Glomerulopathy Using Integrated Bioinformatics Analysis

Background

Cellular senescence is thought to play a significant role in the onset and development of diabetic nephropathy. The goal of this study was to explore potential biomarkers associated with diabetic glomerulopathy from the perspective of senescence.

Methods

Datasets about human glomerular biopsy samples related to diabetic nephropathy were systematically obtained from the Gene Expression Omnibus database. Hub senescence-associated genes were investigated by differential gene analysis and Least Absolute Shrinkage and Selection Operator analysis. Cluster analysis was employed to identify senescence molecular subtypes. A single-cell dataset was used to validate the above findings and further evaluate the senescence environment. The relationship between these genes and the glomerular filtration rate was explored based on the Nephroseq database. These gene expressions have also been explored in various kidney diseases.

Results

Twelve representative senescence-associated genes (VEGFA, IQGAP2, JUN, PLAT, ETS2, ANG, MMP14, VEGFC, SERPINE2, CXCR2, PTGES, and EGF) were finally identified. Biological changes in immune inflammatory response, cell cycle regulation, metabolic regulation, and immune microenvironment have been observed across different molecular subtypes. The above results were also validated based on single-cell analysis. Additionally, we also identified several significantly altered cell communication pathways, including COLLAGEN, PTN, LAMININ, SPP1, and VEGF. Finally, almost all these genes could well predict the occurrence of diabetic glomerulopathy based on receiver operating characteristic analysis and are associated with the glomerular filtration rate. These genes are differently expressed in various kidney diseases.

Conclusion

The present study identified potential senescence-associated biomarkers and further explored the heterogeneity of diabetic glomerulopathy that might provide new insights into the diagnosis, assessment, management, and personalized treatment of DN.

Role of maraviroc and/or rapamycin in the liver of IL10 KO mice with frailty syndrome

Cellular senescence and low-grade inflammation favor the acceleration of aging. The liver is an essential metabolic organ because changes related to its function are related to age-related diseases. The objective of this study was to evaluate the effects of maraviroc (MVC) and/or rapamycin (RAPA) on liver tissue in an experimental model of frailty syndrome in mice, since MVC and RAPA are two molecules able to decrease CCR5 expression, which is overexpressed in patients with frailty. Methods: Eighty male homozygous IL10KO mice were randomly assigned to one of 4 groups (n = 20): i) IL10KO group; ii) MVC group, iii) RAPA group, and iv) MVC-RAPA group. Liver samples were analyzed. Gene expression quantification and western blotting were also performed. The proinflammatory cytokines IL-6 and IL-18 were decreased in MVC and MVC/RAPA groups, IL-12 was decreased in RAPA and MVC/RAPA groups and TNF-α was decreased in all therapeutic groups. P21 was decreased in RAPA and MVC/RAPA groups, Galactosidase beta-1, was also significantly reduced in all therapeutic groups, as were NF-kB1, NF-kB2 and STAT3. In all groups, mTOR and CCL5 were significantly reduced. CCR5 expression was decreased in the MVC and MVC/RAPA groups. Conclusion: MVC and RAPA may protect against some factors involved in liver aging. More studies will be necessary to verify their clinical applications.

Primary oocytes with cellular senescence features are involved in ovarian aging in mice

In mammalian females, quiescent primordial follicles serve as the ovarian reserve and sustain normal ovarian function and egg production via folliculogenesis. The loss of primordial follicles causes ovarian aging. Cellular senescence, characterized by cell cycle arrest and production of the senescence-associated secretory phenotype (SASP), is associated with tissue aging. In the present study, we report that some quiescent primary oocytes in primordial follicles become senescent in adult mouse ovaries. The senescent primary oocytes share senescence markers characterized in senescent somatic cells. The senescent primary oocytes were observed in young adult mouse ovaries, remained at approximately 15% of the total primary oocytes during ovarian aging from 6 months to 12 months, and accumulated in aged ovaries. Administration of a senolytic drug ABT263 to 3-month-old mice reduced the percentage of senescent primary oocytes and the transcription of the SASP cytokines in the ovary. In addition, led to increased numbers of primordial and total follicles and a higher rate of oocyte maturation and female fertility. Our study provides experimental evidence that primary oocytes, a germline cell type that is arrested in meiosis, become senescent in adult mouse ovaries and that senescent cell clearance reduced primordial follicle loss and mitigated ovarian aging phenotypes.

Crosstalk between proximal tubular epithelial cells and other interstitial cells in tubulointerstitial fibrosis after renal injury

The energy needs of tubular epithelial components, especially proximal tubular epithelial cells (PTECs), are high and they heavily depend on aerobic metabolism. As a result, they are particularly vulnerable to various injuries caused by factors such as ischemia, proteinuria, toxins, and elevated glucose levels. Initial metabolic and phenotypic changes in PTECs after injury are likely an attempt at survival and repair. Nevertheless, in cases of recurrent or prolonged injury, PTECs have the potential to undergo a transition to a secretory state, leading to the generation and discharge of diverse bioactive substances, including transforming growth factor-β, Wnt ligands, hepatocyte growth factor, interleukin (IL)-1β, lactic acid, exosomes, and extracellular vesicles. By promoting fibroblast activation, macrophage recruitment, and endothelial cell loss, these bioactive compounds stimulate communication between epithelial cells and other interstitial cells, ultimately worsening renal damage. This review provides a summary of the latest findings on bioactive compounds that facilitate the communication between these cellular categories, ultimately leading to the advancement of tubulointerstitial fibrosis (TIF).

Pulmonary decellularized extracellular matrix (dECM) modified polyethylene terephthalate three-dimensional cell carriers regulate the proliferation and paracrine activity of mesenchymal stem cells

Introduction: Mesenchymal stem cells (MSCs) possess a high degree of self-renewal capacity and in vitro multi-lineage differentiation potential. Decellularized materials have garnered considerable attention due to their elevated biocompatibility, reduced immunogenicity, excellent biodegradability, and the ability to partially mimic the in vivo microenvironment conducive to cell growth. To address the issue of mesenchymal stem cells losing their stem cell characteristics during two-dimensional (2D) cultivation, this study established three-dimensional cell carriers modified with lung decellularized extracellular matrix and assessed its impact on the life activities of mesenchymal stem cells. Methods: This study employed PET as a substrate material, grafting with polydopamine (PDA), and constructing a decellularized extracellular matrix (dECM) coating on its surface, thus creating the PET/PDA/dECM three-dimensional (3D) composite carrier. Subsequently, material characterization of the cellular carriers was conducted, followed by co-culturing with human umbilical cord mesenchymal stem cells in vitro, aiming to investigate the material's impact on the proliferation and paracrine activity of mesenchymal stem cells. Results and Discussion: Material characterization demonstrated successful grafting of PDA and dECM materials, and it had complete hydrophilicity, high porosity, and excellent mechanical properties. The material was rich in various ECM proteins (collagen I, collagen IV , laminin, fibronectin, elastin), indicating good biocompatibility. In long-term in vitro cultivation (14 days) experiments, the PET/PDA/dECM three-dimensional composite carrier significantly enhanced adhesion and proliferation of human umbilical cord-derived mesenchymal stem cells (HUCMSCs), with a proliferation rate 1.9 times higher than that of cells cultured on tissue culture polystyrene (TCPS) at day 14. Furthermore, it effectively maintained the stem cell characteristics, expressing specific antigens for HUCMSCs. Through qPCR, Western blot, and ELISA experiments, the composite carrier markedly promoted the expression and secretion of key cell factors in HUCMSCs. These results demonstrate that the PET/PDA/dECM composite carrier holds great potential for scaling up MSCs' long-term in vitro cultivation and the production of paracrine factors.

Diverse Response to Local Pharmacological Blockade of Sirt1 Cleavage in Age-Induced versus Trauma-Induced Osteoarthritis Female Mice

Objective: Previous studies have shown that the cleavage of Sirt1 contributes to the development of osteoarthritis (OA). In fact, OA was effectively abrogated by the intra-articular (IA) administration of two compounds, one blocking Sirt1 cleavage (CA074me) and the other activating Sirt1 (SRT1720), using a post-traumatically induced model (PTOA) in young female mice. In this study, we attempted to understand if this local treatment is effective in preventing age-associated OA (AOA) progression and symptoms. Design: A group of 17-month-old female C57BL/6J mice were IA administered with CA074me and/or SRT1720 or their combination. Joint histopathological analysis and bone histomorphometry were carried out, with an assessment of knee mechanical hyperalgesia. A serum analysis for NT/CT Sirt1 was carried out along with immunohistochemistry for articular cartilage to detect p16INK4A or γH2A.X. Similarly, meniscal cartilage was monitored for Lef1 and Col1a1 deposition. The data were compared for young female mice subjected to post-traumatic OA (PTOA). Results: Similar to PTOA, combination-treated AOA exhibited improved knee hyperalgesia, yet structural improvements were undetected, corresponding to unchanged NT/CT Sirt1 serum levels. Both AOA and PTOA exhibited unchanged staining for nuclear p16INK4A or γH2A.X and lacked a correlation with OA severity. Contrarily to PTOA, the combination treatment with AOA did not exhibit a local reduction in the Lef1 and Col1 targets. Conclusions: When targeting Sirt1 cleavage, the PTOA and AOA models exhibited a similar pain response to the combination treatment; however, they displayed diverse structural outcomes for joint-related damage, related to Lef1-dependent signaling. Interestingly, nuclear p16INK4A was unaffected in both models, regardless of the treatment's effectiveness. Finally, these findings highlight the variations in the responses between two highly researched OA preclinical models, reflecting OA pathophysiology heterogeneity and variations in gender-related drug-response mechanisms.

Nutrition, Immunity and Aging: Current Scenario and Future Perspectives in Neurodegenerative Diseases

Aging is a gradual decline of physiological function and tissue homeostasis and, in many instances, is related to increased (neuro)-degeneration, together with inflammation, becoming one of the most important risks for developing neurodegenerative diseases. Certain individual nutrients or foods in combination may counteract aging and associated neurodegenerative diseases by promoting a balance between the pro- and anti-inflammatory responses. Thus, nutrition could represent a powerful modulator of this fine balance, other than a modifiable risk factor to contrast inflammaging. This narrative review explores from a broad perspective the impact of nutrition on the hallmarks of aging and inflammation in Alzheimer's disease (AD), Parkinson's disease (PD) and Amyotrophic Lateral Sclerosis Syndrome (ALS), starting from nutrients up to single foods and complex dietary patterns.

Geroscience-Centric Perspective for Geriatric Psychiatry: Integrating Aging Biology With Geriatric Mental Health Research

The geroscience hypothesis asserts that physiological aging is caused by a small number of biological pathways. Despite the explosion of geroscience research over the past couple of decades, the research on how serious mental illnesses (SMI) affects the biological aging processes is still in its infancy. In this review, we aim to provide a critical appraisal of the emerging literature focusing on how we measure biological aging systematically, and in the brain and how SMIs affect biological aging measures in older adults. We will also review recent developments in the field of cellular senescence and potential targets for interventions for SMIs in older adults, based on the geroscience hypothesis.

Telomeres as hotspots for innate immunity and inflammation

Aging is marked by the gradual accumulation of deleterious changes that disrupt organ function, creating an altered physiological state that is permissive for the onset of prevalent human diseases. While the exact mechanisms governing aging remain a subject of ongoing research, there are several cellular and molecular hallmarks that contribute to this biological process. This review focuses on two factors, namely telomere dysfunction and inflammation, which have emerged as crucial contributors to the aging process. We aim to discuss the mechanistic connections between these two distinct hallmarks and provide compelling evidence highlighting the loss of telomere protection as a driver of pro-inflammatory states associated with aging. By reevaluating the interplay between telomeres, innate immunity, and inflammation, we present novel perspectives on the etiology of aging and its associated diseases.