Cellular senescence in ageing: from mechanisms to therapeutic opportunities

Molecular classification of geriatric breast cancer displays distinct senescent subgroups of prognostic significance

Breast cancer in the elderly presents distinct biological characteristics and clinical treatment responses compared with cancer in younger patients. Comprehensive Geriatric Assessment is recommended for evaluating treatment efficacy in elderly cancer patients based on physiological classification. However, research on molecular classification in older cancer patients remains insufficient. In this study, we identified two subgroups with distinct senescent clusters among geriatric breast cancer patients through multi-omics analysis. Using various machine learning algorithms, we developed a comprehensive scoring model called "Sene_Signature," which more accurately distinguished elderly breast cancer patients compared with existing methods and better predicted their prognosis. The Sene_Signature was correlated with tumor immune cell infiltration, as supported by single-cell transcriptomics, RNA sequencing, and pathological data. Furthermore, we observed increased drug responsiveness in patients with a high Sene_Signature to treatments targeting the epidermal growth factor receptor and cell-cycle pathways. We also established a user-friendly web platform to assist investigators in assessing Sene_Signature scores and predicting treatment responses for elderly breast cancer patients. In conclusion, we developed a novel model for evaluating prognosis and therapeutic responses, providing a potential molecular classification that assists in the pre-treatment assessment of geriatric breast cancer.

Podocyte senescence: from molecular mechanisms to therapeutics

As an important component of the glomerular filtration membrane, the state of the podocytes is closely related to kidney function, they are also key cells involved in aging and play a central role in the damage caused by renal aging. Therefore, understanding the aging process of podocytes will allow us to understand their susceptibility to injury and identify targeted protective mechanisms. In fact, the process of physiological aging itself can induce podocyte senescence. Pathological stresses, such as oxidative stress, mitochondrial damage, secretion of senescence-associated secretory phenotype, reduced autophagy, oncogene activation, altered transcription factors, DNA damage response, and other factors, play a crucial role in inducing premature senescence and accelerating aging. Senescence-associated-β-galactosidase (SA-β-gal) is a marker of aging, and β-hydroxybutyric acid treatment can reduce SA-β-gal activity to alleviate cellular senescence and damage. In addition, CCAAT/enhancer-binding protein-α, transforming growth factor-β signaling, glycogen synthase kinase-3β, cycle-dependent kinase, programmed cell death protein 1, and plasminogen activator inhibitor-1 are closely related to aging. The absence or elevation of these factors can affect aging through different mechanisms. Podocyte injury is not an independent process, and injured podocytes interact with the surrounding epithelial cells or other kidney cells to mediate the injury or loss of podocytes. In this review, we discuss the manifestations, molecular mechanisms, biomarkers, and therapeutic drugs for podocyte senescence. We included elamipretide, lithium, calorie restriction, rapamycin; and emerging treatment strategies, such as gene and immune therapies. More importantly, we summarize how podocyte interact with other kidney cells.

Integrated-omics profiling unveils the disparities of host defense to ECM scaffolds during wound healing in aged individuals

Extracellular matrix (ECM) scaffold membranes have exhibited promising potential to better the outcomes of wound healing by creating a regenerative microenvironment around. However, when compared to the application in younger individuals, the performance of the same scaffold membrane in promoting re-epithelialization and collagen deposition was observed dissatisfying in aged mice. To comprehensively explore the mechanisms underlying this age-related disparity, we conducted the integrated analysis, combing single-cell RNA sequencing (scRNA-Seq) with spatial transcriptomics, and elucidated six functionally and spatially distinctive macrophage groups and lymphocytes surrounding the ECM scaffolds. Through intergroup comparative analysis and cell-cell communication, we characterized the dysfunction of Spp1+ macrophages in aged mice impeded the activation of the type Ⅱ immune response, thus inhibiting the repair ability of epidermal cells and fibroblasts around the ECM scaffolds. These findings contribute to a deeper understanding of biomaterial applications in varied physiological contexts, thereby paving the way for the development of precision-based biomaterials tailored specifically for aged individuals in future therapeutic strategies.

Unlocking mitochondrial dysfunction-associated senescence (MiDAS) with NAD+ - A Boolean model of mitochondrial dynamics and cell cycle control

The steady accumulation of senescent cells with aging creates tissue environments that aid cancer evolution. Aging cell states are highly heterogeneous. 'Deep senescent' cells rely on healthy mitochondria to fuel a strong proinflammatory secretome, including cytokines, growth and transforming signals. Yet, the physiological triggers of senescence such as reactive oxygen species (ROS) can also trigger mitochondrial dysfunction, and sufficient energy deficit to alter their secretome and cause chronic oxidative stress - a state termed Mitochondrial Dysfunction-Associated Senescence (MiDAS). Here, we offer a mechanistic hypothesis for the molecular processes leading to MiDAS, along with testable predictions. To do this we have built a Boolean regulatory network model that qualitatively captures key aspects of mitochondrial dynamics during cell cycle progression (hyper-fusion at the G1/S boundary, fission in mitosis), apoptosis (fission and dysfunction) and glucose starvation (reversible hyper-fusion), as well as MiDAS in response to SIRT3 knockdown or oxidative stress. Our model reaffirms the protective role of NAD+ and external pyruvate. We offer testable predictions about the growth factor- and glucose-dependence of MiDAS and its reversibility at different stages of reactive oxygen species (ROS)-induced senescence. Our model provides mechanistic insights into the distinct stages of DNA-damage induced senescence, the relationship between senescence and epithelial-to-mesenchymal transition in cancer and offers a foundation for building multiscale models of tissue aging.

An anti-senescence hydrogel with pH-responsive drug release for mitigating intervertebral disc degeneration and low back pain

Oxidative stress and aging lead to progressive senescence of nucleus pulposus (NP) cells, resulting in intervertebral disc (IVD) degeneration (IVDD). In some cases, degenerative IVD can further cause low back pain (LBP). Several studies have confirmed that delaying and rejuvenating the senescence of NP cells can attenuate IVDD. However, the relatively closed tissue structure of IVDs presents challenges for the local application of anti-senescence drugs. Here, we prepared an anti-senescence hydrogel by conjugating phenylboronic acid-modified gelatin methacryloyl (GP) with quercetin to alleviate IVDD by removing senescent NP cells. The hydrogel exhibited injectability, biodegradability, prominent biocompatibility and responsive release of quercetin under pathological conditions. In vitro experiments demonstrated that the hydrogel could reduce the expression of senescence markers and restore the metabolic balance in senescent NP cells. In vivo studies validated that a single injection of the hydrogel in situ could maintain IVD tissue structure and alleviate sensitivity to noxious mechanical force in the rat models, indicating a potential therapeutic approach for ameliorating IVDD and LBP. This approach helps prevent potential systemic toxicity associated with systemic administration and reduces the morbidity resulting from repeated injections of free drugs into the IVD, providing a new strategy for IVDD treatment.

IGF2BP3/NCBP1 complex inhibits renal tubular senescence through regulation of CDK6 mRNA stability

Renal aging and the subsequent rise in kidney-related diseases are attributed to senescence in renal tubular epithelial cells (RTECs). Our study revealed that the abnormal expression of insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3), a reader of RNA N6-methyladenosine, is critically involved in cisplatin-induced renal tubular senescence. In cisplatin-induced senescence of RTECs, the promoter activity and transcription of IGF2BP3 is markedly suppressed. It was due to the down regulation of MYC proto-oncogene (MYC), which regulates IGF2BP3 transcription by binding to the putative site at 1852-1863 of the IGF2BP3 promoter. Overexpression of IGF2BP3 ameliorated cisplatin-induced renal tubular senescence in vitro. Mechanistic studies revealed that IGF2BP3 inhibits cellular senescence in RTECs by enhancing cyclin-dependent kinase 6 (CDK6) mRNA stability and increasing its expression. The inhibition effect of IGF2BP3 on tubular senescence is partially reversed by the knockdown of CDK6. Further, IGF2BP3 recruits nuclear cap binding protein subunit 1 (NCBP1) and inhibits CDK6 mRNA decay, by recognizing m6A modification. Specifically, IGF2BP3 recognizes m6A motif "GGACU" at nucleotides 110-114 in the 5' untranslated region (UTR) field of CDK6 mRNA. The involvement of IGF2BP3/CDK6 in alleviating tubular senescence was confirmed in a cisplatin-induced acute kidney injury (AKI)-to-chronic kidney disease (CKD) model. Clinical data also suggests an age-related decrease in IGF2BP3 and CDK6 levels in renal tissue or serum samples from patients. These findings suggest that IGF2BP3/CDK6 may be a promising target in cisplatin-induced tubular senescence and renal failure.

Stretch-induced damage in endothelial monolayers

Endothelial cells are constantly exposed to mechanical stimuli, of which mechanical stretch has shown various beneficial or deleterious effects depending on whether loads are within physiological or pathological levels, respectively. Vascular properties change with age, and on a cell-scale, senescence elicits changes in endothelial cell mechanical properties that together can impair its response to stretch. Here, high-rate uniaxial stretch experiments were performed to quantify and compare the stretch-induced damage of monolayers consisting of young, senescent, and aged endothelial populations. The aged and senescent phenotypes were more fragile to stretch-induced damage. Prominent damage was detected by immunofluorescence and scanning electron microscopy as intercellular and intracellular void formation. Damage increased proportionally to the applied level of deformation and, for the aged and senescent phenotype, induced significant detachment of cells at lower levels of stretch compared to the young counterpart. Based on the phenotypic difference in cell-substrate adhesion of senescent cells indicating more mature focal adhesions, a discrete network model of endothelial cells being stretched was developed. The model showed that the more affine deformation of senescent cells increased their intracellular energy, thus enhancing the tendency for cellular damage and impending detachment. Next to quantifying for the first-time critical levels of endothelial stretch, the present results indicate that young cells are more resilient to deformation and that the fragility of senescent cells may be associated with their stronger adhesion to the substrate.

Efferocytosis and Bone Dynamics

PURPOSE OF REVIEW

This review summarizes the recently published scientific evidence regarding the role of efferocytosis in bone dynamics and skeletal health.

RECENT FINDINGS

Several types of efferocytes have been identified within the skeleton, with macrophages being the most extensively studied. Efferocytosis is not merely a 'clean-up' process vital for maintaining skeletal homeostasis; it also plays a crucial role in promoting resolution pathways and orchestrating bone dynamics, such as osteoblast-osteoclast coupling during bone remodeling. Impaired efferocytosis has been associated with aging-related bone loss and various skeletal pathologies, including osteoporosis, osteoarthritis, rheumatoid arthritis, and metastatic bone diseases. Accordingly, emerging evidence suggests that targeting efferocytic mechanisms has the potential to alleviate these conditions. While efferocytosis remains underexplored in the skeleton, recent discoveries have shed light on its pivotal role in bone dynamics, with important implications for skeletal health and pathology. However, there are several knowledge gaps and persisting technical limitations that must be addressed to fully unveil the contributions of efferocytosis in bone.

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

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

From rest to repair: Safeguarding genomic integrity in quiescent cells

Quiescence is an important non-pathological state in which cells pause cell cycle progression temporarily, sometimes for decades, until they receive appropriate proliferative stimuli. Quiescent cells make up a significant proportion of the body, and maintaining genomic integrity during quiescence is crucial for tissue structure and function. While cells in quiescence are spared from DNA damage associated with DNA replication or mitosis, they are still exposed to various sources of endogenous DNA damage, including those induced by normal transcription and metabolism. As such, it is vital that cells retain their capacity to effectively repair lesions that may occur and return to the cell cycle without losing their cellular properties. Notably, while DNA repair pathways are often found to be downregulated in quiescent cells, emerging evidence suggests the presence of active or differentially regulated repair mechanisms. This review aims to provide a current understanding of DNA repair processes during quiescence in mammalian systems and sheds light on the potential pathological consequences of inefficient or inaccurate repair in quiescent cells.

Discovery of pyrimidine-2,4-diamine analogues as efficiency anticancer drug by targeting GTSE1

A series of pyrimidine-2,4-diamine analogues were designed and synthesized. Their anticancer activity and the underlying mechanism against colorectal cancer (CRC) HCT116 cells and non-small cell lung cancer (NSCLC) A549 cells were investigated. The results demonstrated that the active compound Y18 significantly inhibited cancer cell proliferation by inducing robust cell cycle arrest and cell senescence through the persistence of DNA damage. Additionally, Y18 exhibited significant inhibitory effects on the adhesion, migration and invasion of cancer cells in vitro. Mechanistically, Y18 achieved these anticancer activities by suppressing GTSE1 transcription and expression. Y18 also effectively inhibited tumor growth in vivo with minimal side effects. Furthermore, Y18 exhibited a suitable half-life and oral bioavailability (16.27%), with limited inhibitory activity on CYP isoforms. Taken together, these results suggested that Y18 could be a potential chemotherapeutic drug for cancer treatment, particularly in cases of GTSE1 overexpressed cancers.

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

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

Suppression of GATA3 promotes epithelial-mesenchymal transition and simultaneous cellular senescence in human extravillous trophoblasts

The regulatory mechanism of the transcription factor GATA3 in the differentiation and maturation process of extravillous trophoblasts (EVT) in early pregnancy placenta, as well as its relevance to the occurrence of pregnancy disorders, remains poorly understood. This study leveraged single-cell RNA sequencing data from placental organoid models and placental tissue to explore the dynamic changes in GATA3 expression during EVT maturation. The expression pattern exhibited an initial upregulation followed by subsequent downregulation, with aberrant GATA3 localization observed in cases of recurrent miscarriage (RM). By identifying global targets regulated by GATA3 in primary placental EVT cells, JEG3, and HTR8/SVneo cell lines, this study offered insights into its regulatory mechanisms across different EVT cell models. Shared regulatory targets among these cell types and activation of trophoblast cell marker genes emphasized the importance of GATA3 in EVT differentiation and maturation. Knockdown of GATA3 in JEG3 cells led to repression of GATA3-induced epithelial-mesenchymal transition (EMT), as evidenced by changes in marker gene expression levels and enhanced migration ability. Additionally, interference with GATA3 accelerated cellular senescence, as indicated by reduced proliferation rates and increased activity levels for senescence-associated β-galactosidase enzyme, along with elevated expression levels for senescence-associated genes. This study provides comprehensive insights into the dual role of GATA3 in regulating EMT and cellular senescence during EVT differentiation, shedding light on the dynamic changes in GATA3 expression in normal and pathological placental conditions.

TDP-43 ameliorates aging-related cartilage degradation through preventing chondrocyte senescence

Senescent chondrocytes or signaling mechanisms leading to senescence are promising new therapeutic approaches for ameliorating cartilage degradation. Herein, we show that the transactive response DNA/RNA-binding protein (TDP-43) regulates chondrocyte senescence and ameliorates cartilage degradation. First, a significant decrease in TDP-43 was observed in 16-month-old mice compared with younger mice. Immunohistochemistry (IHC) analysis of mouse articular cartilage showed that p21, p16, p53, and matrix metalloprotein-13 (MMP13) were increased, but laminB1 and Collagen type II alpha1 1 chain (Col2a1) were decreased in 16-month-old mice. Furthermore, TDP-43 levels were decreased in vivo following D-galactose (D-gal) induction. Therefore, we investigated the role of TDP-43 in the senescent chondrocytes. ATDC5 cells were induced to overexpress TDP-43. Western blot analysis showed increased expression of laminB1, Ki67, and PCNA but decreased expression of p21, p16, p53, and MMP13. Senescence-associated-β-galactosidase (SA-β-Gal) assay, γH2AX staining, and EdU were performed to assess changes in chondrocytes, showing weaker SA-β-Gal and γH2AX staining but stronger EdU and Alican Blue staining. However, TDP-43 deficiency had opposing effects, and similar to D-gal stimulation results. Taken together, our data verified that TDP-43 negatively correlated with senescence markers, positively correlated with cell proliferation markers, and could alleviate cartilage degradation induced by D-gal. This may be an essential mechanism of cellular senescence and cartilage degradation.

Radix rehmanniae praeparata extracts ameliorate hepatic ischemia-reperfusion injury by reversing LRP1-NOTCH1-C/EBPβ axis-mediated senescence fate of LSECs

BACKGROUND

Hepatic ischemia-reperfusion injury (HIRI) is commonly observed in cases of extensive hepatic resection and involves complex mechanisms. Cell senescence has been recognized as a factor in liver injury including HIRI, where it presents as a pro-inflammatory phenotype called senescence-associated secretory phenotype (SASP). Radix Rehmanniae Praeparata (RRP) is a commonly utilized traditional Chinese medicine known for its hepatoprotective, anti-aging and antioxidant qualities. Despite its recognized benefits, the specific mechanisms by which RRP may impede the progression of HIRI through the regulation of cell senescence and the identification of the most potent anti-aging extracts from RRP remain unclear.

MATERIALS AND METHODS

Here, we first applied different chemical analysis methods to identify the RRP aqueous extract (RRPAE) and active fractions of RRP. Next, we constructed a surgically established mouse model and a hypoxia-reoxygenation (HR)-stimulated liver sinusoidal endothelial cells (LSECs) model to explore the underlying mechanism of RRP against HIRI through transcriptomics and multiple molecular biology experiments.

RESULTS

After identifying active ingredients in RRP, we observed that RRP and its factions effectively restored LSECs fenestration and improved inflammation, cellular swelling and vascular continuity in the hepatic sinusoidal region during HIRI. Transcriptomic results revealed that RRP might reverse HIRI-induced senescence through the NOTCH signaling pathway and cell categorization further showed that the senescent cell population in HIRI liver was primarily LSECs rather than other cell types. Different RRPAE, especially RRP glucoside (RRPGLY), improved LSECs senescence and suppressed the expression of pro-inflammatory SASP genes either induced by HR insult or NOTCH1 activator, which was accompanied with the inhibition of LRP1-NOTCH1-C/EBPβ pathways. Additionally, the specific inhibition of NOTCH1 by siRNA synergistically enhanced the hepatoprotective effect of RRPGLY. The ChIP-qPCR results further showed that C/EBPβ was enriched at the promoter of a representative SASP, Il-1β, in hypoxic LSECs but was significantly inhibited by RRPGLY.

CONCLUSION

Our study not only clarified the potential mechanism of RRP active extractions in alleviating HIRI, but also highlighted RRPGLY was the main component of RRP that exerted anti-aging and anti-HIRI effects, providing a fresh perspective on the use of RRP to improve HIRI.

Identification of immunosenescence of unconventional T cells in hepatocellular carcinoma

Accumulation of senescent cells is a recognized feature in hepatocellular carcinoma (HCC), but their specific types and prognostic implications remain under investigation. This study aimed to delineate senescent cell types and their senescent patterns in HCC using publicly available bulk and single-cell mRNA sequencing data. Through gene expression and gene set enrichment analysis, we identified distinct senescent patterns within HCC samples. Notably, unconventional T cells, specifically natural killer T cells and γδT cells, were found to be the predominant senescent cell types. These cells exhibited enriched pathways related to DNA damage, senescence and the negative regulation of lymphocyte activation. Furthermore, we observed upregulation of the mTOR signaling pathway, which correlated positively with the expression of senescence-associated genes. This suggests a potential regulatory role for mTOR in the senescence of HCC. Strikingly, patients with elevated expression of senescence markers, including p16INK4A, p21, and GLB1, demonstrated significantly reduced overall survival rates. Our findings indicate that immunosenescence in unconventional T cells may play a role in HCC progression. The potential therapeutic implications of targeting the mTOR pathway or eliminating senescent unconventional T cells warrant further exploration to improve HCC patient outcomes.

The N-acetylglucosaminyltransferase Radical Fringe contributes to defects in JAG1-dependent turnover and signaling of NOTCH3 CADASIL mutants

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a genetic vascular dementia characterized by age-related degeneration of vascular mural cells and accumulation of a NOTCH3 mutant protein. NOTCH3 functions as a signaling receptor, activating downstream gene expression in response to ligands like JAG1 and DLL4, which regulate the development and survival of mural cells. This signal transduction process is thought to be connected with NOTCH3 endocytic degradation. However, the specific cellular circumstances that modulate turnover and signaling efficacy of NOTCH3 mutant protein remain largely unknown. Here, we found elevated NOTCH3 and Radical fringe (RFNG) expression in senescent human pericyte cells. We then investigated impacts of RFNG on glycosylation, degradation, and signal activity of three NOTCH3 CADASIL mutants (R90C, R141C, and C185R) in EGF-like repeat-2, 3, and 4, respectively. LC-MS/MS analysis showed that RFNG modified NOTCH3 WT and C185R to different degrees. Additionally, coculture experiments demonstrated that RFNG significantly promoted JAG1-dependent degradation of NOTCH3 WT but not that of R141C and C185R mutants. Furthermore, RFNG exhibited a greater inhibitory effect on JAG1-mediated activity of NOTCH3 R141C and C185R compared to that of NOTCH3 WT and R90C. In summary, our findings suggest that NOTCH3 R141C and C185R mutant proteins are relatively susceptible to accumulation and signaling impairment under cellular conditions of RFNG and JAG1 coexistence.

The Aging Immune System: A Critical Attack on Ischemic Stroke

Ischemic stroke caused by cerebrovascular embolism is an age-related disease with high rates of disability and mortality. Although the mechanisms of immune and inflammatory development after stroke have been of great interest, most studies have neglected the critical and unavoidable factor of age. As the global aging trend intensifies, the number of stroke patients is constantly increasing, emphasizing the urgency of finding effective measures to address the needs of elderly stroke patients. The concept of "immunosenescence" appears to explain the worse stroke outcomes in older individuals. Immune remodeling due to aging involves dynamic changes at all levels of the immune system, and the overall consequences of central (brain-resident) and peripheral (non-brain-resident) immune cells in stroke vary according to the age of the individual. Lastly, the review outlines recent strategies aimed at immunosenescence to improve stroke prognosis.

Targeting Senescent Cells in Atherosclerosis: Pathways to Novel Therapies

Targeting senescent cells has recently emerged as a promising strategy for treating age-related diseases, such as atherosclerosis, which significantly contributes to global cardiovascular morbidity and mortality. This review elucidates the role of senescent cells in the development of atherosclerosis, including persistently damaging DNA, inducing oxidative stress and secreting pro-inflammatory factors known as the senescence-associated secretory phenotype. Therapeutic approaches targeting senescent cells to mitigate atherosclerosis are summarized in this review, which include the development of senotherapeutics and immunotherapies. These therapies are designed to either remove these cells or suppress their deleterious effects. These emerging therapies hold potential to decelerate or even alleviate the progression of AS, paving the way for new avenues in cardiovascular research and treatment.

Effect of Semaglutide on Physical Function, Body Composition, and Biomarkers of Aging in Older Adults With Overweight and Insulin Resistance: Protocol for an Open-Labeled Randomized Controlled Trial

BACKGROUND

Older adults with type 2 diabetes mellitus (T2DM) or prediabetes are at increased risk of adverse changes in body composition, physical function, and aging-related biomarkers compared to those with normal glucose tolerance. Semaglutide is a glucagon-like peptide 1 receptor agonist that has been approved for T2DM and chronic weight management. Although semaglutide is effective for weight loss and T2DM management, its effects on lean body mass, physical function, and biomarkers of aging are understudied in older adults.

OBJECTIVE

This study aims to compare the effects of lifestyle counseling with and that without semaglutide on body composition, physical function, and biomarkers of aging in older adults.

METHODS

This is an open-label randomized controlled trial. A total of 20 adults (aged 65 years and older) with elevated BMI (27-40 kg/m2) and prediabetes or well-controlled T2DM (hemoglobin A1c 5.7%-7.5%) are recruited, stratified by sex, and randomized 1:1 to one of 2 groups (semaglutide plus lifestyle counseling vs lifestyle counseling alone) and followed up for 5 months. Those in the semaglutide group are titrated to 1 mg weekly, as tolerated, for 12 weeks. Lifestyle counseling is given by registered dietitians and based on the Diabetes Prevention Program Lifestyle Change Program. Our primary outcomes include changes in lean mass, physical function, and biomarkers of aging. Body composition is measured by dual-energy x-ray absorptiometry and includes total fat mass and lean mass. Physical function is measured by 6-minute walk distance, grip strength, and short physical performance battery. Biomarkers of aging are measured in blood, skeletal muscle, and abdominal adipose tissue to include C-reactive protein, interleukin-6, tumor necrosis factors α, and β galactosidase staining.

RESULTS

The study was funded in December 2021 with a projected data collection period from spring 2023 through summer 2024.

CONCLUSIONS

Despite the elevated risk of adverse changes in body composition, physical function, and biomarkers of aging among older adults with glucose intolerance and elevated adiposity, the benefits and risks of commonly prescribed antihyperglycemic or weight loss medications such as semaglutide are understudied. This study aims to fill this knowledge gap to inform clinicians about the potential for additional clinically meaningful, nonglycemic effects of semaglutide.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05786521; https://clinicaltrials.gov/study/NCT05786521.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/62667.

Discovering common pathogenetic processes between periodontitis and Alzheimer's disease by bioinformatics and system biology approach

BACKGROUND

There is increasing evidence that inflammation plays a key role in the pathophysiology of periodontitis (PT) and Alzheimer's disease (AD), but the roles of inflammation in linking PT and AD are not clear. Our aim is to analyze the potential molecular mechanisms between these two diseases using bioinformatics and systems biology approaches.

METHODS

To elucidate the link between PT and AD, we selected shared genes (SGs) with gene-disease-association scores of ≥ 0.1 from the Disease Gene Network (DisGeNET) database, followed by extracting the hub genes. Based on these genes, we constructed gene ontology (GO) enrichment analysis, pathway enrichment analysis, protein-protein interaction (PPI) networks, transcription factors (TFs)-gene networks, microRNAs (miRNAs)-gene regulatory networks, and gene-disease association analyses. Finally, the Drug Signatures database (DSigDB) was utilized to predict candidate molecular drugs related to hub genes.

RESULTS

A total of 21 common SGs between PT and AD were obtained. Cell cytokine activity, inflammatory response, and extracellular membrane were the most important enriched items in GO analysis. Interleukin-10 Signaling, LTF Danger Signal Response Pathway, and RAGE Pathway were identified as important shared pathways. IL6, IL10, IL1B, TNF, IFNG, CXCL8, CCL2, MMP9, TLR4 were identified as hub genes. Both shared pathways and hub genes are closely related to endoplasmic reticulum (ER) stress and mitochondrial dysfunction. Importantly, glutathione, simvastatin, and dexamethasone were identified as important candidate drugs for the treatment of PT and AD.

CONCLUSIONS

There is a close link between PT and AD pathogenesis, which may involve in the inflammation, ER and mitochondrial function.

Targeting Cell Senescence and Senolytics: Novel Interventions for Age-Related Endocrine Dysfunction

Multiple changes occur in hormonal regulation with aging and across various endocrine organs. These changes are associated with multiple age-related disorders and diseases. A better understanding of responsible underling biological mechanisms could help in the management of multiple endocrine disorders over and above hormone replacement therapy (HRT). Cellular senescence is involved in multiple biological aging processes and pathologies common in elderly individuals. Cellular senescence, which occurs in many older individuals but also across the lifespan in association with tissue damage, acute and chronic diseases, certain drugs, and genetic syndromes, may contribute to such endocrine disorders as osteoporosis, metabolic syndrome, and type 2 diabetes mellitus. Drugs that selectively induce senescent cell removal, "senolytics,", and drugs that attenuate the tissue-destructive secretory state of certain senescent cells, "senomorphics," appear to delay the onset of or alleviate multiple diseases, including but not limited to endocrine disorders such as diabetes, complications of obesity, age-related osteoporosis, and cancers as well as atherosclerosis, chronic kidney disease, neurodegenerative disorders, and many others. More than 30 clinical trials of senolytic and senomorphic agents have already been completed, are underway, or are planned for a variety of indications. Targeting senescent cells is a novel strategy that is distinct from conventional therapies such as HRT, and thus might address unmet medical needs and can potentially amplify effects of established endocrine drug regimens, perhaps allowing for dose decreases and reducing side effects.

IL-17A exacerbates corpus cavernosum fibrosis and neurogenic erectile dysfunction by inducing CSMC senescence via the mTORC2-ACACA pathway

BACKGROUND

Neurogenic erectile dysfunction, characterized by neurological repair disorders and progressive corpus cavernosum fibrosis (CCF), is an unbearable disease with limited treatment success. IL-17A exhibits a complex role in tissue remodelling. Nevertheless, the precise role and underlying mechanisms of IL-17A in CCF under denervation remain unclear.

METHODS

PCR array was employed to identified differentially expressed genes between neurogenic ED and normal rats. IL-17A expression and its main target cells were analyzed using Western blotting, immunofluorescence and immunohistochemistry. The phenotypic regulation of IL-17A on corpus cavernosum smooth muscle cells (CSMCs) was evaluated by cell cycle experiments and SA-β-Gal staining. The mechanism of IL-17A was elucidated using non-target metabolomics and siRNA technique. Finally, IL-17A antagonist and ABT-263 (an inhibitor of B-cell lymphoma 2/w/xL) were utilized to enhance the therapeutic effect in a rat model of neurogenic ED.

RESULTS

IL-17A emerged as the most significantly upregulated gene in the corpus cavernosum of model rats. It augmented the senescence transformation and fibrotic response of CSMCs, and exhibited a strong correlation with CCF. Mechanistically, IL-17A facilitated CCF by activating the mTORC2-ACACA signalling pathway, upregulating of CSMCs lipid synthesis and senescence transition, and increasing the secretion of fibro-matrix proteins. In vivo, the blockade of IL-17A-senescence signalling improved erectile function and alleviated CCF in neurogenic ED.

CONCLUSIONS

IL-17A assumes a pivotal role in denervated CCF by activating the mTORC2-ACACA signalling pathway, presenting itself as a potential therapeutic target for effectively overcoming CCF and erection rehabilitation in neurogenic ED.

USP14 inhibition promotes DNA damage repair and represses ovarian granulosa cell senescence in premature ovarian insufficiency

BACKGROUND

Premature ovarian insufficiency (POI) is a condition characterized by a substantial decline or loss of ovarian function in women before the age of 40. However, the pathogenesis of POI remains to be further elucidated, and specific targeted drugs which could delay or reverse ovarian reserve decline are urgently needed. Abnormal DNA damage repair (DDR) and cell senescence in granulosa cells are pathogenic mechanisms of POI. Ubiquitin-specific protease 14 (USP14) is a key enzyme that regulates the deubiquitylation of DDR-related proteins, but whether USP14 participates in the pathogenesis of POI remains unclear.

METHODS

We measured USP14 mRNA expression in granulosa cells from biochemical POI (bPOI) patients. In KGN cells, we used IU1 and siRNA-USP14 to specifically inhibit USP14 and constructed a cell line stably overexpressing USP14 to examine its effects on DDR function and cellular senescence in granulosa cells. Next, we explored the therapeutic potential of IU1 in POI mouse models induced by D-galactose.

RESULTS

USP14 expression in the granulosa cells of bPOI patients was significantly upregulated. In KGN cells, IU1 treatment and siUSP14 transfection decreased etoposide-induced DNA damage levels, promoted DDR function, and inhibited cell senescence. USP14 overexpression increased DNA damage, impaired DDR function, and promoted cell senescence. Moreover, IU1 treatment and siUSP14 transfection increased nonhomologous end joining (NHEJ), upregulated RNF168, Ku70, and DDB1, and increased ubiquitinated DDB1 levels in KGN cells. Conversely, USP14 overexpression had the opposite effects. Intraperitoneal IU1 injection alleviated etoposide-induced DNA damage in granulosa cells, ameliorated the D-galactose-induced POI phenotype, promoted DDR, and inhibited cell senescence in ovarian granulosa cells in vivo.

CONCLUSIONS

Upregulated USP14 in ovarian granulosa cells may play a role in POI pathogenesis, and targeting USP14 may be a potential POI treatment strategy. Our study provides new insights into the pathogenesis of POI and a novel POI treatment strategy.

SIRT6 alleviates senescence induced by Porphyromonas gingivalis in human gingival fibroblasts

OBJECTIVE

Bidirectional influences between senescence and inflammation are newly discovered. This study aimed to clarify the roles and mechanism of Porphyromonas gingivalis (P. gingivalis) in exacerbating senescence in human gingival fibroblasts (HGFs).

DESIGN

Subgingival plaque and gingivae were collected from twenty-four periodontitis patients and eighteen periodontally healthy subjects. Quantities of P. gingivalis in subgingival plaque were explored using real-time PCR and the expressions of p53, p21 and SIRT6 in gingivae were detected by IHC. Moreover, senescence in HGFs was induced by P. gingivalis lipopolysaccharide (LPS) and the expressions of senescence-related β-galactosidase (SA-β-gal), p53, p21 and senescence-associated secretory phenotype (IL-6 and IL-8) with or without treatment by SIRT6 activator UBCS039 were explored by IHC, western blot and ELISA, respectively. In addition, the levels of SIRT6, Nrf2, HO-1 and reactive oxygen species (ROS) were examined by western blot and flow cytometry.

RESULTS

Quantities of P. gingivalis in subgingival plaque and semi-quantitative scores of p53 and p21 in gingivae of periodontitis patients were increased compared with healthy controls (p < 0.05), while SIRT6 score in periodontitis patients was decreased (p < 0.001). Quantities of P. gingivalis were positively correlated with p53 and p21 scores (0.6 < r < 0.9, p < 0.01), and negatively correlated with SIRT6 score (-0.9 < r<-0.6, p < 0.01). Moreover, P. gingivalis LPS increased the levels of SA-β-gal, p53, p21, IL-6, IL-8 and ROS and decreased the levels of SIRT6, Nrf2 and HO-1 in HGFs, which was rescued by UBCS039 (p < 0.05).

CONCLUSIONS

P. gingivalis LPS could induce senescence of HGFs, which could be reversed by SIRT6 via Nrf2-HO-1 signaling pathway.

Impaired degradation of PLCG1 by chaperone-mediated autophagy promotes cellular senescence and intervertebral disc degeneration

Defects in chaperone-mediated autophagy (CMA) are associated with cellular senescence, but the mechanism remains poorly understood. Here, we found that CMA inhibition induced cellular senescence in a calcium-dependent manner and identified its role in TNF-induced senescence of nucleus pulposus cells (NPC) and intervertebral disc degeneration. Based on structural and functional proteomic screens, PLCG1 (phospholipase C gamma 1) was predicted as a potential substrate for CMA deficiency to affect calcium homeostasis. We further confirmed that PLCG1 was a key mediator of CMA in the regulation of intracellular calcium flux. Aberrant accumulation of PLCG1 caused by CMA blockage resulted in calcium overload, thereby inducing NPC senescence. Immunoassays on human specimens showed that reduced LAMP2A, the rate-limiting protein of CMA, or increased PLCG1 was associated with disc senescence, and the TNF-induced disc degeneration in rats was inhibited by overexpression of Lamp2a or knockdown of Plcg1. Because CMA dysregulation, calcium overload, and cellular senescence are common features of disc degeneration and other age-related degenerative diseases, the discovery of actionable molecular targets that can link these perturbations may have therapeutic value.Abbreviation: ATRA: all-trans-retinoic acid; BrdU: bromodeoxyuridine; CDKN1A/p21: cyclin dependent kinase inhibitor 1A; CDKN2A/p16-INK4A: cyclin dependent kinase inhibitor 2A; CMA: chaperone-mediated autophagy; DHI: disc height index; ER: endoplasmic reticulum; IP: immunoprecipitation; IP3: inositol 1,4,5-trisphosphate; ITPR/IP3R: inositol 1,4,5-trisphosphate receptor; IVD: intervertebral disc; IVDD: intervertebral disc degeneration; KD: knockdown; KO: knockout; Leu: leupeptin; MRI: magnetic resonance imaging; MS: mass spectrometry; N/L: NH4Cl and leupeptin; NP: nucleus pulposus; NPC: nucleus pulposus cells; PI: protease inhibitors; PLC: phospholipase C; PLCG1: phospholipase C gamma 1; ROS: reactive oxygen species; RT-qPCR: real-time quantitative reverse transcription PCR; SA-GLB1/β-gal: senescence-associated galactosidase beta 1; SASP: senescence-associated secretory phenotype; STV: starvation; TMT: tandem mass tag; TNF: tumor necrosis factor; TP53: tumor protein p53; UPS: ubiquitin-proteasome system.

Co-Delivery of Valsartan and Metformin from a Thermosensitive Hydrogel-Nanoparticle System Promotes Collagen Production in Proliferating and Senescent Primary Human Dermal Fibroblasts

Aging negatively impacts skin health, notably through the senescent cell phenotype, which reduces collagen production and leads to thinner, more fragile skin prone to injuries and chronic wounds. We designed a drug delivery system that addresses these age-related issues using a hybrid hydrogel-nanoparticle system that utilizes a poly(δ-valerolactone-co-lactide)-b-poly(ethylene-glycol)-b-poly(δ-valerolactone-co-lactide) (PVLA-PEG-PVLA) hydrogel. This hydrogel allows for the local, extended release of therapeutics targeting both proliferating and senescent cells. The PVLA-PEG-PVLA hydrogel entrapped valsartan, and metformin-loaded liposomes functionalized with a fibronectin-mimetic peptide, PR_b. Metformin acts as a senomorphic, reversing aspects of cellular senescence, and valsartan, an angiotensin receptor blocker, promotes collagen production. This combination treatment partially reversed the senescent phenotype and improved collagen production in senescent dermal fibroblasts from both young and old adults. Our codelivery hydrogel-nanoparticle system offers a promising treatment for improving age-related dermal pathologies.

Preexisting senescent fibroblasts in the aged bladder create a tumor-permissive niche through CXCL12 secretion

Aging is a major risk factor for cancer, but the precise mechanism by which aging promotes carcinogenesis remains largely unknown. Here, using genetically modified mouse models, we show that p16high senescent (p16h-sn) fibroblasts accumulate with age, constitute inflammatory cancer-associated fibroblasts (CAFs) and promote tumor growth in bladder cancer models. Single-cell RNA sequencing of fibroblasts from aged mice revealed higher expression of the C-X-C motif chemokine 12 gene (Cxcl12) in p16h-sn fibroblasts than in p16low fibroblasts. Elimination of p16h-sn cells or inhibition of CXCL12 signaling notebly suppressed bladder tumor growth in vivo. We identified high expression levels of SMOC2, GUCY1A1 (GUCY1A3), CXCL12, CRISPLD2, GAS1 and LUM as a signature of p16h-sn CAFs in humans and mice, which was associated with age and poor prognosis in patients with advanced and nonadvanced bladder cancer. Here we show that p16h-sn fibroblasts in the aged bladder create a cancer-permissive niche and promote tumor growth by secreting CXCL12.

Pirfenidone inhibits CCL2-mediated Treg chemotaxis induced by palbociclib and fulvestrant in HR+/HER2- breast cancer

In human epidermal growth factor receptor 2-negative (HR+/HER2-) breast cancer, the most prevalent subtype, the pathological complete response (pCR) rate after neoadjuvant chemotherapy is less than 18 %, and the survival of patients with advanced-stage disease is approximately 34 %, highlighting the critical demand for more potent therapies. Recent research has underscored the substantial therapeutic benefits of the combination of CDK4/6 inhibitors and fulvestrant (Ful) in managing HR+/HER2- breast cancer. These therapeutics not only curtail tumor proliferation but also alter the tumor immune microenvironment, suggesting novel avenues for immunotherapy for this breast cancer subtype. Flow cytometry, PCR, WB, and RNA-seq experiments revealed that the combination of the CDK4/6 inhibitor palbociclib (Pal) with Ful upregulated CCL2 in tumor cells by inducing the SASP and activating the MAPK signaling pathway. CCL2 attracts Tregs to the tumor microenvironment, where it exerts an immunosuppressive effect. By administering the CCL2 inhibitor pirfenidone, we inhibited these effects and enhanced the antitumor efficacy of Pal + Ful. Our research revealed an immunosuppressive effect of CDK4/6 inhibitors and fulvestrant and suggested that CCL2 inhibitors may be a viable approach for treating patients with advanced HR+/HER2- breast cancer.

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

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

A p21-ATD mouse model for monitoring and eliminating senescent cells and its application in liver regeneration post injury

Cellular senescence associates with pathological aging and tissue dysfunctions. Studies utilizing mouse models for cell lineage tracings have emphasized the importance of senescence heterogeneity in different organs and cell types. Here, we constructed a p21- (Akaluc - tdTomato - Diphtheria Toxin Receptor [DTR]) (ATD) mouse model to specifically study the undefined mechanism for p21-expressing senescent cells in the aged and liver injury animals. The successful expressions of these genes enabled in vitro flow cytometric sorting, in vivo tracing, and elimination of p21-expressing senescent cells. During the natural aging process, p21-expressing cells were found in various tissues of p21-ATD mice. Eliminating p21-expressing cells in the aged p21-ATD mice recovered their multiple biological functions. p21-ATD/Fah-/- mice, bred from p21-ATD mice and fumarylacetoacetate hydrolase (Fah)-/- mice of liver injury, showed that the majority of their senescent hepatocytes were the phenotype of p21+ rather than p16+. Furthermore, eliminating the p21-expressing hepatocytes significantly promoted the engraftment of grafted hepatocytes and facilitated liver repopulation, resulting in significant recovery from liver injury. Our p21-ATD mouse model serves as an optimal model for studying the pattern and function of p21-expressing senescent cells under the physical and pathological conditions during aging.

10-hydroxy-2-decenoic acid prevents osteoarthritis by targeting aspartyl β hydroxylase and inhibiting chondrocyte senescence in male mice preclinically

Osteoarthritis is a degenerative joint disease with joint pain as the main symptom, caused by fibrosis and loss of articular cartilage. Due to the complexity and heterogeneity of osteoarthritis, there is a lack of effective individualized disease-modifying osteoarthritis drugs in clinical practice. Chondrocyte senescence is reported to participate in occurrence and progression of osteoarthritis. Here we show that small molecule 10-hydroxy-2-decenoic acid suppresses cartilage degeneration and relieves pain in the chondrocytes, cartilage explants from osteoarthritis patients, surgery-induced medial meniscus destabilization or naturally aged male mice. We further confirm that 10-hydroxy-2-decenoic acid exerts a protective effect by targeting the glycosylation site in the Asp_Arg_Hydrox domain of aspartyl β-hydroxylase. Mechanistically, 10-hydroxy-2-decenoic acid alleviate cellular senescence through the ERK/p53/p21 and GSK3β/p16 pathways in the chondrocytes. Our study uncovers that 10-hydroxy-2-decenoic acid modulate cartilage metabolism by targeting aspartyl β-hydroxylase to inhibit chondrocyte senescence in osteoarthritis. 10-hydroxy-2-decenoic acid may be a promising therapeutic drug against osteoarthritis.

Structural characterization, anti-aging activity and mechanisms investigation in vivo of a polysaccharide from Anthriscus sylvestris

Anthriscus sylvestris (L.) Hoffm has a long history of use for anti-aging, although the anti-aging properties of its decoction ingredients have been seldom explored. This study marks the first detailed examination of the in vivo anti-aging activity of A. sylvestris roots polysaccharide (AP). Structural analyses revealed that AP is a neutral heteropolysaccharide with an average molecular weight (Mw) of 34.17 kDa, comprising glucose, xylose, galactose, mannose, and arabinose, with a backbone primarily of 1,4-α-D-Glc and minor branching at 1,4,6-α-D-Man. Its advanced structure is characterized by stable triple-helical chains and nanoscale agglomerated spherical particles. Using a D-gal-induced aging mouse model, further investigation showed that AP boosts the activity of various antioxidant enzymes via the Nrf2/HO-1/NQO1 signaling pathway. Aging-related immune decline was also mitigated by an increase in lymphocyte production in thymus. Moreover, AP reduced inflammation and downregulated aging genes p53 and p21 in hippocampus and liver tissues, enhanced the cholinergic system, and improved liver functions and lipid metabolism. The collective impact of these mechanisms underscores the robust anti-aging properties of AP. These findings highlight the anti-aging and immunomodulatory potential of A. sylvestris polysaccharide, broadening the understanding of its active components.

Supplementation with l-arginine and nitrates vs age and individual physiological reactivity

Ageing is a natural ontogenetic phenomenon that entails a decrease in the adaptive capacity of the organism, as a result of which the body becomes less adaptable to stressful conditions. Nitrate and nitrite enter the body from exogenous sources and from nitrification of ammonia nitrogen by intestinal microorganisms. This review considers the mechanisms of action of l-arginine, a known inducer of nitric oxide (NO) biosynthesis, and nitrates as supplements in the processes of ageing and aggravated stress states, in which mechanisms of individual physiological reactivity play an important role. This approach can be used as an element of individual therapy or prevention of premature ageing processes depending on the different levels of initial reactivity of the functional systems. A search was performed of the PubMed, Scopus, and Google Scholar databases (n = 181 articles) and the author's own research (n = 4) up to May 5, 2023. The review presents analyses of data on targeted treatment of NO generation by supplementation with l-arginine or nitrates, which is a promising means for prevention of hypoxic conditions frequently accompanying pathological processes in an ageing organism. The review clarifies the role of the individual state of physiological reactivity, using the example of individuals with a high predominance of cholinergic regulatory mechanisms who already have a significant reserve of adaptive capacity. In studies of the predominance of adrenergic influences, a poorly trained organism as well as an elderly organism correspond to low resistance, which is an additional factor of damage at increased energy expenditure.

CONCLUSION

It is suggested that the role of NO synthesis from supplementation of dietary nitrates and nitrites increases with age rather than from oxygen-dependent biosynthetic reactions from l-arginine supplementation.

DXA-based appendicular composition measures in healthy aging Caucasian Greek women: a cross-sectional study

As the global population of older persons increases, age-related medical conditions will have a greater impact on public health. DXA-derived bone and soft tissue metrics are associated with adverse clinical events in aging persons. This study aims to investigate the regional body composition of the appendices by whole-body DXA scans, and the age-related relationships between measures of bone and soft tissue in healthy Caucasian females of a Greek origin residing in the Mediterranean area. Body composition of the legs and the arms was analyzed, and lean mass (LM) and fat mass (FM) metrics were calculated in 330 women aged 20-85 years, using DXA. Peak bone mineral density (BMD) of the legs and arms was achieved between ages 20-30 and 41-50 years, respectively. The overall BMD reduction with age was for the legs 43% and the arms 32.2% (p < 0.001). Peak %LM of the legs and the arms was achieved between ages 20-30. The overall reduction of %LM with age was for the legs 22.5% (p < 0.001) and arms 6.6% (p < 0.05). Peak %FM of the legs and arms was attained between ages 31-40 and 61-70, respectively. The overall %FM reduction with age was for the legs and arms 7.5% and 1.9% (p > 0.05). In appendicular sites, Greek women reach peak values of bone mass in the legs first, in early adulthood. Bone loss predominates in the legs as women age. Also, with advancing age Greek women show preferential significant decreases of %LM and %FM in the legs as opposed to the arms. Although variation in appendicular bone and soft tissue metrics is present, the implications of variable biological crosstalks among the tissue components as women age may ultimately lay the foundation for future clinical trials aimed at healthy aging.

Senescence-associated microvascular endothelial dysfunction: A focus on the blood-brain and blood-retinal barriers

The blood-brain barrier (BBB) and blood-retinal barrier (BRB) constitute critical physiochemical interfaces, precisely orchestrating the bidirectional communication between the brain/retina and blood. Increased permeability or leakage of these barriers has been demonstrably linked to age-related vascular and parenchymal damage. While it has been suggested that the gradual aging process may coincide with disruptions in these barriers, this phenomenon is significantly exacerbated in individuals with age-related neurodegenerative disorders (ARND). This review focuses on the microvascular endothelium, a key constituent of BBB and BRB, highlighting the impact of endothelial senescence on barrier dysfunction and exploring recent discoveries regarding core pathways implicated in its breakdown. Subsequently, we address the "vascular senescence hypothesis" for ARND, with a particular emphasis on Alzheimer's disease and age-related macular degeneration, centered on endothelial senescence. Finally, we discuss potential senotherapeutic strategies targeting barrier dysfunction.

Deapioplatycodin D promotes cell senescence induced by P21 through the mediation of incomplete mitophagy via BNIP3L

Deapioplatycodin D (DPD) is a triterpenoid saponin extracted from the root of Platycodon grandiflorum, which is a common source of medicine and food. Platycodon grandiflorum saponins have anti-inflammatory, antioxidative, antitumor, and immunity-promoting effects. However, the effect of DPD on hepatocellular carcinoma (HCC) cells has not been reported. The purpose of this study was to explore the cytotoxic effects and molecular mechanisms of DPD on HCC cells. Our study revealed that DPD significantly inhibits the proliferation of HCC, as demonstrated by the CCK-8 assay, and then we analyzed the inhibitory effects and pathways of DPD on HCC cells by Western blot and immunofluorescence assay, and found that DPD could increase the changes of autophagy-related protein levels, but had no significant effect on the expression of apoptosis-related proteins, and induced cell senescence. Then, transcriptomics analysis revealed that differential genes were significantly enriched in cell senescence and autophagy pathways and significant expression of mitochondrial autophagy-related gene BNIP3L and senescence-related gene P21. Subsequently, autophagy and cell senescence were analyzed using gene silencing, and it was found that DPD caused mitochondrial damage and promoted reactive oxygen species production, leading to the inhibition of autophagic fluxes and mitophagy via BNIP3L, and that DPD also mediated cell senescence via P21. Here, we found that autophagy promoted cell senescence, resulting in the inhibition of HCC cell proliferation. Similar results were obtained in the tumor-bearing model in vivo. In conclusion, DPD induces incomplete mitophagy and cell senescence in HCC cells, thereby inhibiting HCC cell proliferation. DPD is a potential new strategy for treating HCC.

Pathological mechanisms of kidney disease in ageing

The kidney is a metabolically active organ that requires energy to drive processes such as tubular reabsorption and secretion, and shows a decline in function with advancing age. Various molecular mechanisms, including genomic instability, telomere attrition, inflammation, autophagy, mitochondrial function, and changes to the sirtuin and Klotho signalling pathways, are recognized regulators of individual lifespan and pivotal factors that govern kidney ageing. Thus, mechanisms that contribute to ageing not only dictate renal outcomes but also exert a substantial influence over life expectancy. Conversely, kidney dysfunction, in the context of chronic kidney disease (CKD), precipitates an expedited ageing trajectory in individuals, leading to premature ageing and a disconnect between biological and chronological age. As CKD advances, age-related manifestations such as frailty become increasingly conspicuous. Hence, the pursuit of healthy ageing necessitates not only the management of age-related complications but also a comprehensive understanding of the processes and markers that underlie systemic ageing. Here, we examine the hallmarks of ageing, focusing on the mechanisms by which they affect kidney health and contribute to premature organ ageing. We also review diagnostic methodologies and interventions for premature ageing, with special consideration given to the potential of emerging therapeutic avenues to target age-related kidney diseases.

ROS-mediated lysosomal membrane permeabilization and autophagy inhibition regulate bleomycin-induced cellular senescence

Bleomycin exhibits effective chemotherapeutic activity against multiple types of tumors, and also induces various side effects, such as pulmonary fibrosis and neuronal defects, which limit the clinical application of this drug. Macroautophagy/autophagy has been recently reported to be involved in the functions of bleomycin, and yet the mechanisms of their crosstalk remain insufficiently understood. Here, we demonstrated that reactive oxygen species (ROS) produced during bleomycin activation hampered autophagy flux by inducing lysosomal membrane permeabilization (LMP) and obstructing lysosomal degradation. Exhaustion of ROS with N-acetylcysteine relieved LMP and autophagy defects. Notably, we observed that LMP and autophagy blockage preceded the emergence of cellular senescence during bleomycin treatment. In addition, promoting or inhibiting autophagy-lysosome degradation alleviated or exacerbated the phenotypes of senescence, respectively. This suggests the alternation of autophagy activity is more a regulatory mechanism than a consequence of bleomycin-induced cellular senescence. Taken together, we reveal a specific role of bleomycin-induced ROS in mediating defects of autophagic degradation and further regulating cellular senescence in vitro and in vivo. Our findings, conversely, indicate the autophagy-lysosome degradation pathway as a target for modulating the functions of bleomycin. These provide a new perspective for optimizing bleomycin as a clinically applicable chemotherapeutics devoid of severe side-effects.Abbreviations: AT2 cells: type II alveolar epithelial cells; ATG7: autophagy related 7; bEnd.3: mouse brain microvascular endothelial cells; BNIP3L: BCL2/adenovirus E1B interacting protein 3-like; CCL2: C-C motif chemokine ligand 2; CDKN1A: cyclin dependent kinase inhibitor 1A; CDKN2A: cyclin dependent kinase inhibitor 2A; FTH1: ferritin heavy polypeptide 1; γ-H2AX: phosphorylated H2A.X variant histone; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; HUVEC: human umbilical vein endothelial cells; HT22: hippocampal neuronal cell lines; Il: interleukin; LAMP: lysosomal-associated membrane protein; LMP: lysosome membrane permeabilization; MTORC1: mechanistic target of rapamycin kinase complex 1; NAC: N-acetylcysteine; NCOA4: nuclear receptor coactivator 4; PI3K: phosphoinositide 3-kinase; ROS: reactive oxygen species; RPS6KB/S6K: ribosomal protein S6 kinase; SA-GLB1/β-gal: senescence-associated galactosidase, beta 1; SAHF: senescence-associated heterochromatic foci; SASP: senescence-associated secretory phenotype; SEC62: SEC62 homolog, preprotein translocation; SEP: superecliptic pHluorin; SQSTM1/p62: sequestosome 1; TFEB: transcription factor EB.

Unlocking the role of herbal cosmeceutical in anti-ageing and skin ageing associated diseases

The process of skin ageing is a natural biological phenomenon characterised by the emergence of wrinkles, age spots, sagging skin, and dryness over time. The increasing significance of skin in physical attractiveness has heightened skincare concerns. Anti-ageing cosmetics play a pivotal role in nurturing the skin, enhancing its quality, and promoting overall health. Today, cosmetics have evolved beyond mere aesthetics and are now integral to individual wellness. The contemporary quest for perpetual youth has intensified, prompting a deeper exploration into the skin ageing process. This comprehensive exploration delves into various elements involved in skin ageing, encompassing cells such as stem and endothelial cells, blood vessels, soft tissues, and signalling pathways. The molecular basis of skin ageing, including biochemical factors like reactive oxygen species, damaged DNA, free radicals, ions, and proteins (mRNA), is scrutinised alongside relevant animal models. The article critically analyzes the outcomes of utilising herbal components, emphasising their advantageous anti-ageing properties. The factors contributing to skin ageing, mechanistic perspectives, management approaches involving herbal cosmeceutical, and associated complications (especially cardiovascular diseases, Parkinson's, Alzheimer's, etc.) are succinctly addressed. In addition, the manuscript further summarises the recent patented innovations and toxicity of the herbal cosmeceuticals for anti-ageing and ageing associated disorders. Despite progress, further research is imperative to unlock the full potential of herbal components as anti-ageing agents.

The association of circulating bioenergetic metabolites with healthy human aging

Aging is an inevitable and gradual decline in several biological functions. Mitochondrial dysfunction is one of the most important hallmarks of aging. In this context, alterations in metabolites associated with mitochondrial dysfunction may serve as a significant biomarker. This study aimed to investigate the existence of a relationship between the key metabolites involved in bioenergetics metabolism and aging. 53 volunteers ranged 20-85 years participated in the study. We tested the association between different tricarboxylic acid (TCA) cycle metabolites, fatty acid metabolism, and amino acid metabolism with age, sex, body composition, and proxy markers of aging such as walking speed, grip strength and chair test. We found that lactic acid negatively correlated with age while several fatty acid metabolites, such as azelaic, sebacic, and linoleic acids, showed positive correlations with age (p < 0.05). Sex-specific trends, such as glycerol, and dodecanoic acid, were also observed for certain metabolites. Furthermore, citric acid levels were found to have a significant association with physical function and body composition measures. Participants with higher citric acid levels displayed improved performance in physical tests and favorable body composition indices. Additionally, fumaric acid and adipic acid showed positive correlations with fat-free body mass, while sebacic acid was negatively associated with measures of fat mass. These findings underscore the importance of understanding the role of circulating bioenergetics metabolites with age, sex variations, and their potential implications in body composition and physical performance.

Cellular senescence in metastatic prostate cancer: A therapeutic opportunity or challenge (Review)

The treatment of patients with metastatic prostate cancer (PCa) is considered to be a long‑standing challenge. Conventional treatments for metastatic PCa, such as radical prostatectomy, radiotherapy and androgen receptor‑targeted therapy, induce senescence of PCa cells to a certain extent. While senescent cells can impede tumor growth through the restriction of cell proliferation and increasing immune clearance, the senescent microenvironment may concurrently stimulate the secretion of a senescence‑associated secretory phenotype and diminish immune cell function, which promotes PCa recurrence and metastasis. Resistance to established therapies is the primary obstacle in treating metastatic PCa as it can lead to progression towards an incurable state of disease. Therefore, understanding the molecular mechanisms that underly the progression of PCa is crucial for the development of novel therapeutic approaches. The present study reviews the phenomenon of treatment‑induced senescence in PCa, the dual role of senescence in PCa treatments and the mechanisms through which senescence promotes PCa metastasis. Furthermore, the present review discusses potential therapeutic strategies to target the aforementioned processes with the aim of providing insights into the evolving therapeutic landscape for the treatment of metastatic PCa.

A Senomorphlytic Three-Drug Combination Discovered in Salsola collina for Delaying Aging Phenotypes and Extending Healthspan

The pursuit of pharmacological interventions in aging aims focuses on maximizing safety and efficacy, prompting an exploration of natural products endowed with inherent medicinal properties. Subsequently, this work establishes a unique library of plant extracts sourced from Yunnan Province, China. Screening of this herbal library herein revealed that Salsola collina (JM10001) notably enhances both lifespan and healthspan in C. elegans. Further analysis via network pharmacology indicates that the p53 signaling pathway plays a crucial role in mediating the anti-aging effects of JM10001. Additionally, this work identifies that a composition, designated as JM10101 and comprising three chemical constituents of JM10001, preserves the original lifespan-extending activity in C. elegans. Both JM10001 and JM10101 mitigate aging symptoms in senescence-accelerated mice treated with doxorubicin and in naturally aged mice. Notably, JM10101 exhibits a more sophisticated senomorphlytic role encompassing both senomorphic and senolytic functions than JM10001 in the modulation of senescent cells, offering a promising strategy for the discovery of combination drugs in the rational development of anti-aging therapies.

Targeting senescence-associated secretory phenotypes to remodel the tumour microenvironment and modulate tumour outcomes

Tumour cell senescence can be induced by various factors, including DNA damage, inflammatory signals, genetic toxins, ionising radiation and nutrient metabolism. The senescence-associated secretory phenotype (SASP), secreted by senescent tumour cells, possesses the capacity to modulate various immune cells, including macrophages, T cells, natural killer cells and myeloid-derived suppressor cells, as well as vascular endothelial cells and fibroblasts within the tumour microenvironment (TME), and this modulation can result in either the promotion or suppression of tumorigenesis and progression. Exploring the impact of SASP on the TME could identify potential therapeutic targets, yet limited studies have dissected its functions. In this review, we delve into the causes and mechanisms of tumour cell senescence. We then concentrate on the influence of SASP on the tumour immune microenvironment, angiogenesis, extracellular matrix and the reprogramming of cancer stem cells, along with their associated tumour outcomes. Last, we present a comprehensive overview of the diverse array of senotherapeutics, highlighting their prospective advantages and challenge for the treatment of cancer patients. KEY POINTS: Senescence-associated secretory phenotype (SASP) secretion from senescent tumour cells significantly impacts cancer progression and biology. SASP is involved in regulating the remodelling of the tumour microenvironment, including immune microenvironment, vascular, extracellular matrix and cancer stem cells. Senotherapeutics, such as senolytic, senomorphic, nanotherapy and senolytic vaccines, hold promise for enhancing cancer treatment efficacy.

PQBP3 prevents senescence by suppressing PSME3-mediated proteasomal Lamin B1 degradation

Senescence of nondividing neurons remains an immature concept, with especially the regulatory molecular mechanisms of senescence-like phenotypes and the role of proteins associated with neurodegenerative diseases in triggering neuronal senescence remaining poorly explored. In this study, we reveal that the nucleolar polyglutamine binding protein 3 (PQBP3; also termed NOL7), which has been linked to polyQ neurodegenerative diseases, regulates senescence as a gatekeeper of cytoplasmic DNA leakage. PQBP3 directly binds PSME3 (proteasome activator complex subunit 3), a subunit of the 11S proteasome regulator complex, decreasing PSME3 interaction with Lamin B1 and thereby preventing Lamin B1 degradation and senescence. Depletion of endogenous PQBP3 causes nuclear membrane instability and release of genomic DNA from the nucleus to the cytosol. Among multiple tested polyQ proteins, ataxin-1 (ATXN1) partially sequesters PQBP3 to inclusion bodies, reducing nucleolar PQBP3 levels. Consistently, knock-in mice expressing mutant Atxn1 exhibit decreased nuclear PQBP3 and a senescence phenotype in Purkinje cells of the cerebellum. Collectively, these results suggest homologous roles of the nucleolar protein PQBP3 in cellular senescence and neurodegeneration.

Cytosolic DNA initiates a vicious circle of aging-related endothelial inflammation and mitochondrial dysfunction via STING: the inhibitory effect of Cilostazol

Endothelial senescence, aging-related inflammation, and mitochondrial dysfunction are prominent features of vascular aging and contribute to the development of aging-associated vascular disease. Accumulating evidence indicates that DNA damage occurs in aging vascular cells, especially in endothelial cells (ECs). However, the mechanism of EC senescence has not been completely elucidated, and so far, there is no specific drug in the clinic to treat EC senescence and vascular aging. Here we show that various aging stimuli induce nuclear DNA and mitochondrial damage in ECs, thus facilitating the release of cytoplasmic free DNA (cfDNA), which activates the DNA-sensing adapter protein STING. STING activation led to a senescence-associated secretory phenotype (SASP), thereby releasing pro-aging cytokines and cfDNA to further exacerbate mitochondrial damage and EC senescence, thus forming a vicious circle, all of which can be suppressed by STING knockdown or inhibition. Using next-generation RNA sequencing, we demonstrate that STING activation stimulates, whereas STING inhibition disrupts pathways associated with cell senescence and SASP. In vivo studies unravel that endothelial-specific Sting deficiency alleviates aging-related endothelial inflammation and mitochondrial dysfunction and prevents the development of atherosclerosis in mice. By screening FDA-approved vasoprotective drugs, we identified Cilostazol as a new STING inhibitor that attenuates aging-related endothelial inflammation both in vitro and in vivo. We demonstrated that Cilostazol significantly inhibited STING translocation from the ER to the Golgi apparatus during STING activation by targeting S162 and S243 residues of STING. These results disclose the deleterious effects of a cfDNA-STING-SASP-cfDNA vicious circle on EC senescence and atherogenesis and suggest that the STING pathway is a promising therapeutic target for vascular aging-related diseases. A proposed model illustrates the central role of STING in mediating a vicious circle of cfDNA-STING-SASP-cfDNA to aggravate age-related endothelial inflammation and mitochondrial damage.

Integrative analysis of the transcriptome and metabolome reveals the importance of hepatokine FGF21 in liver aging

Aging is a contributor to liver disease. Hence, the concept of liver aging has become prominent and has attracted considerable interest, but its underlying mechanism remains poorly understood. In our study, the internal mechanism of liver aging was explored via multi-omics analysis and molecular experiments to support future targeted therapy. An aged rat liver model was established with d-galactose, and two other senescent hepatocyte models were established by treating HepG2 cells with d-galactose and H2O2. We then performed transcriptomic and metabolomic assays of the aged liver model and transcriptome analyses of the senescent hepatocyte models. In livers, genes related to peroxisomes, fatty acid elongation, and fatty acid degradation exhibited down-regulated expression with aging, and the hepatokine Fgf21 expression was positively correlated with the down-regulation of these genes. In senescent hepatocytes, similar to the results found in aged livers, FGF21 expression was also decreased. Moreover, the expressions of cell cycle-related genes were significantly down-regulated, and the down-regulated gene E2F8 was the key cell cycle-regulating transcription factor. We then validated that FGF21 overexpression can protect against liver aging and that FGF21 can attenuate the declines in the antioxidant and regenerative capacities in the aging liver. We successfully validated the results from cellular and animal experiments using human liver and blood samples. Our study indicated that FGF21 is an important target for inhibiting liver aging and suggested that pharmacological prevention of the reduction in FGF21 expression due to aging may be used to treat liver aging-related diseases.