Aging of the cells: Insight into cellular senescence and detection Methods

Transcriptome analysis of porcine oocytes during postovulatory aging

Decreased oocyte quality is a significant contributor to the decline in female fertility that accompanies aging in mammals. Oocytes rely on mRNA stores to support their survival and integrity during the protracted period of transcriptional dormancy as they await ovulation. However, the changes in mRNA levels and interactions that occur during porcine oocyte maturation and aging remain unclear. In this study, the mRNA expression profiles of porcine oocytes during the GV, MII, and aging (24 h after the MII stage) stages were explored by transcriptome sequencing to identify the key genes and pathways that affect oocyte maturation and postovulatory aging. The results showed that 10,929 genes were coexpressed in porcine oocytes during the GV stage, MII stage, and aging stage. In addition, 3037 genes were expressed only in the GV stage, 535 genes were expressed only in the MII stage, and 120 genes were expressed only in the aging stage. The correlation index between the GV and MII stages (0.535) was markedly lower than that between the MII and aging stages (0.942). A total of 3237 genes, which included 1408 upregulated and 1829 downregulated genes, were differentially expressed during porcine oocyte postovulatory aging (aging stage vs. MII stage). Key functional genes, including ATP2A1, ATP2A3, ATP2B2, NDUFS1, NDUFA2, NDUFAF3, SREBF1, CYP11A1, CYP3A29, GPx4, CCP110, STMN1, SPC25, Sirt2, SYCP3, Fascin1/2, PFN1, Cofilin, Tmod3, FLNA, LRKK2, CHEK1/2, DDB1/2, DDIT4L, and TONSL, and key molecular pathways, such as the calcium signaling pathway, MAPK signaling pathway, TGF-β signaling pathway, PI3K/Akt signaling pathway, FoxO signaling pathway, gap junctions, and thermogenesis, were found in abundance during porcine postovulatory aging. These genes are mainly involved in the regulation of many biological processes, such as oxidative stress, calcium homeostasis, mitochondrial function, and lipid peroxidation, during porcine oocyte postovulatory aging. These results contribute to a more in-depth understanding of the biological changes, key regulatory genes and related biological pathways that are involved in oocyte aging and provide a theoretical basis for improving the efficiency of porcine embryo production in vitro and in vivo.

Anti-aging effects of Lacticaseibacillus paracasei PS117 on cognitive and intestinal health in naturally-aged mice: A focus on senescence-related proteins and microbiota composition

The rising global aging population underscores the urgency of maintaining the health and well-being of the elderly while reducing the healthcare burden. Anti-aging probiotics have emerged as a promising strategy. This study identified a novel anti-senescence probiotic, Lacticaseibacillus paracasei PS117 (PS117). The effects of PS117 and heat-treated PS117 (HT-PS117) supplementation on cognitive function of naturally-aged male mice were investigated. It was found that PS117 supplementation improved the cognitive performance of aged mice in the Y-maze test. Furthermore, the level of senescence-related protein p16INK4a (p16) were reduced, while anti-senescence protein sirtuin 1 (Sirt1) were increased in the hippocampus. In addition, there was an overall improvement in the intestinal function. Distinct changes in the gut microbiota were also identified, suggesting a potential contribution to the beneficial effects of PS117 supplementation. In conclusion, these results suggest that PS117 supplements could improve cognitive and intestinal functions in naturally-aged mice, while HT-117 improves only intestinal function, possibly by improving the gut microbiota composition.

Strategies to make human skin models based on cellular senescence for ageing research

Human skin ageing is closely related to the ageing of the whole organism, and it's a continuous multisided process that is influenced not only by genetic and physiological factors but also by the cumulative impact of environmental factors. Currently, there is a scientific community need for developing skin models representing ageing processes to (i) enhance understanding on the mechanisms of ageing, (ii) discover new drugs for the treatment of age-related diseases, and (iii) develop effective dermo-cosmetics. Bioengineers worldwide are trying to reproduce skin ageing in the laboratory aiming to better comprehend and mitigate the senescence process. This review provides details on the main ageing molecular mechanisms and procedures to obtain in vitro aged skin models.

Mesenchymal stem cells-derived exosomes alleviate senescence of retinal pigment epithelial cells by activating PI3K/AKT-Nrf2 signaling pathway in early diabetic retinopathy

Diabetic retinopathy (DR) is a major cause of vision loss and blindness in adults. Cellular senescence was involved in the pathogenesis of early-stage DR and is positively correlated with progression. Thus, our study aimed at exploring the effect and potential mechanism of Mesenchymal stem cells-derived exosomes (MSCs-EXOs) on Retinal Pigment Epithelial (RPE) cells senescence at an early stage of DR in vivo and in vitro. ARPE-19 cells were incubated in high glucose (HG) medium mixed with MSCs-EXOs to observe the changes in cell viability. Senescence-associated β-galactosidase (SA-β-gal) staining, Western blot and qRT-PCR were used to assess the expression of senescence-related genes and antioxidant mediators. Quantitative Real-Time polymerase chain reaction (qRT-PCR), Optical coherence tomography (OCT) Hematoxylin and eosin (HE) staining and Electroretinogram (ERG) were respectively used to verify cellular senescence, the structure and function of the retina. Our findings demonstrated that MSCs-EXOs inhibited HG-induced senescence in ARPE-19 cells. Furthermore, MSCs-EXOs reduced HG-induced cell apoptosis and oxidative stress levels while promoting cell proliferation. Mechanistically, HG suppressed PI3K/AKT phosphorylation as well as nuclear factor erythroid 2-related factor 2 (Nrf2) expression along with its downstream target gene expression in ARPE-19 cells. However, MSCs-EXOs reversed these changes by alleviating cellular senescence while enhancing antioxidant activity. In line with our results in vitro, MSCs-EXOs significantly ameliorated hyperglycemia-induced senescence in DR mice by downregulating mRNA expression of P53, P21, P16, and SASP. Additionally, MSCs-EXOs improved the functional and structural integrity of the retina in DR mice. Our study revealed the protective effect of MSCs-EXOs on cellular senescence, offering new insights for the treatment of DR.

Metformin rejuvenates Nap1l2-impaired immunomodulation of bone marrow mesenchymal stem cells via metabolic reprogramming

Ageing and cell senescence of mesenchymal stem cells (MSCs) limited their immunomodulation properties and therapeutic application. We previously reported that nucleosome assembly protein 1-like 2 (Nap1l2) contributes to MSCs senescence and osteogenic differentiation. Here, we sought to evaluate whether Nap1l2 impairs the immunomodulatory properties of MSCs and find a way to rescue the deficient properties. We demonstrated that metformin could rescue the impaired migration properties and T cell regulation properties of OE-Nap1l2 BMSCs. Moreover, metformin could improve the impaired therapeutic efficacy of OE-Nap1l2 BMSCs in the treatment of colitis and experimental autoimmune encephalomyelitis in mice. Mechanistically, metformin was capable of upregulating the activation of AMPK, synthesis of l-arginine and expression of inducible nitric oxide synthase in OE-Nap1l2 BMSCs, leading to an increasing level of nitric oxide. This study indicated that Nap1l2 negatively regulated the immunomodulatory properties of BMSCs and that the impaired functions could be rescued by metformin pretreatment via metabolic reprogramming. This strategy might serve as a practical therapeutic option to rescue impaired MSCs functions for further application.

Biomarkers of Cellular Senescence and Aging: Current State-of-the-Art, Challenges and Future Perspectives

Population aging has increased the global prevalence of aging-related diseases, including cancer, sarcopenia, neurological disease, arthritis, and heart disease. Understanding aging, a fundamental biological process, has led to breakthroughs in several fields. Cellular senescence, evinced by flattened cell bodies, vacuole formation, and cytoplasmic granules, ubiquitously plays crucial roles in tissue remodeling, embryogenesis, and wound repair as well as in cancer therapy and aging. The lack of universal biomarkers for detecting and quantifying senescent cells, in vitro and in vivo, constitutes a major limitation. The applications and limitations of major senescence biomarkers, including senescence-associated β-galactosidase staining, telomere shortening, cell-cycle arrest, DNA methylation, and senescence-associated secreted phenotypes are discussed. Furthermore, explore senotherapeutic approaches for aging-associated diseases and cancer. In addition to the conventional biomarkers, this review highlighted the in vitro, in vivo, and disease models used for aging studies. Further, technologies from the current decade including multi-omics and computational methods used in the fields of senescence and aging are also discussed in this review. Understanding aging-associated biological processes by using cellular senescence biomarkers can enable therapeutic innovation and interventions to improve the quality of life of older adults.

Non-Canonical STING-PERK Pathway Modulation of Cellular Senescence and Therapeutic Response in Sepsis-Associated Acute Kidney Injury

Abstract-This study explored the role of the non-canonical STING-PERK signaling pathway in sepsis-associated acute kidney injury (SA-AKI). Gene expression data from the GEO database and serum STING protein levels in patients with SA-AKI were analyzed. An LPS-induced mouse model and an in vitro model using HK-2 cells were used to investigate the role of STING in SA-AKI. STING expression was suppressed using shRNA silencing technology and the STING inhibitor C176. Kidney function, inflammatory markers, apoptosis, and senescence were measured. The role of the STING-PERK pathway was investigated by silencing PERK in HK-2 cells and administering the PERK inhibitor GSK2606414. STING mRNA expression and serum STING protein levels were significantly higher in patients with SA-AKI. Suppressing STING expression improved kidney function, reduced inflammation, and inhibited apoptosis and senescence. Silencing PERK or administering GSK2606414 suppressed the inflammatory response, cell apoptosis, and senescence, suggesting that PERK is a downstream effector in the STING signaling pathway. The STING-PERK signaling pathway exacerbates cell senescence and apoptosis in SA-AKI. Inhibiting this pathway could provide potential therapeutic targets for SA-AKI treatment.

Nicotinamide N-Methyltransferase (NNMT): A New Hope for Treating Aging and Age-Related Conditions

The complex process of aging leads to a gradual deterioration in the function of cells, tissues, and the entire organism, thereby increasing the risk of disease and death. Nicotinamide N-methyltransferase (NNMT) has attracted attention as a potential target for combating aging and its related pathologies. Studies have shown that NNMT activity increases over time, which is closely associated with the onset and progression of age-related diseases. NNMT uses S-adenosylmethionine (SAM) as a methyl donor to facilitate the methylation of nicotinamide (NAM), converting NAM into S-adenosyl-L-homocysteine (SAH) and methylnicotinamide (MNA). This enzymatic action depletes NAM, a precursor of nicotinamide adenine dinucleotide (NAD+), and generates SAH, a precursor of homocysteine (Hcy). The reduction in the NAD+ levels and the increase in the Hcy levels are considered important factors in the aging process and age-related diseases. The efficacy of RNA interference (RNAi) therapies and small-molecule inhibitors targeting NNMT demonstrates the potential of NNMT as a therapeutic target. Despite these advances, the exact mechanisms by which NNMT influences aging and age-related diseases remain unclear, and there is a lack of clinical trials involving NNMT inhibitors and RNAi drugs. Therefore, more in-depth research is needed to elucidate the precise functions of NNMT in aging and promote the development of targeted pharmaceutical interventions. This paper aims to explore the specific role of NNMT in aging, and to evaluate its potential as a therapeutic target.

Targeting mitochondria for ovarian aging: new insights into mechanisms and therapeutic potential

Ovarian aging is a complex process characterized by a decline in oocyte quantity and quality, directly impacting fertility and overall well-being. Recent researches have identified mitochondria as pivotal players in the aging of ovaries, influencing various hallmarks and pathways governing this intricate process. In this review, we discuss the multifaceted role of mitochondria in determining ovarian fate, and outline the pivotal mechanisms through which mitochondria contribute to ovarian aging. Specifically, we emphasize the potential of targeting mitochondrial dysfunction through innovative therapeutic approaches, including antioxidants, metabolic improvement, biogenesis promotion, mitophagy enhancement, mitochondrial transfer, and traditional Chinese medicine. These strategies hold promise as effective means to mitigate age-related fertility decline and preserve ovarian health. Drawing insights from advanced researches in the field, this review provides a deeper understanding of the intricate interplay between mitochondrial function and ovarian aging, offering valuable perspectives for the development of novel therapeutic interventions aimed at preserving fertility and enhancing overall reproductive health.

Faulty Gap Filling in Nucleotide Excision Repair Leads to Double-Strand Break Formation in Senescent Cells

The change of repair efficiency of UV-induced pyrimidine dimers due to aging was examined in replicatively senesced fibroblasts. The fibroblasts with repeated passages showed the characteristics of cellular senescence, including irreversible cell cycle arrest, elevated β-galactosidase activity, and senescence-associated secretory phenotype. The incision efficiency of oligonucleotide containing UV lesions was similar regardless of cell doubling levels, but the gap filling process was impaired in replicatively senescent cells. The releases of xeroderma pigmentosum group G, proliferating cell nuclear antigen, and replication protein A from damaged sites were delayed, which might have disturbed the DNA polymerase progression. The persistent single-stranded DNA was likely converted to double-strand breaks, leading to ataxia telangiectasia-mutated phosphorylation and 53BP1 foci formation. Phosphorylated histone H2AX (γ-H2AX) induction mainly occurred in G1 phase in senescent cells, not in S phase such as in normal cells, indicating that replication stress-independent double-strand breaks might be formed. MRE11 having nuclease activity accumulated to damaged sites at early time point after UV irradiation but not released in senescent cells. The pharmacological studies using specific inhibitors for the nuclease activity suggested that MRE11 contributed to the enlargement of single-stranded DNA gap, facilitating the double-strand break formation.

Improvement in Epigenetic Aging Clock Induced by BioBran Containing Rice Kefiran in Relation to Various Biomarkers: A Pilot Study

Many lifestyle-related diseases such as cancer, dementia, myocardial infarction, and stroke are known to be caused by aging, and the WHO's ICD-11 (International Classification of Diseases, 11th edition) created the code "aging-related" in 2022. In other words, aging is irreversible but aging-related diseases are reversible, so taking measures to treat them is important for health longevity and preventing other diseases. Therefore, in this study, we used BioBran containing rice kefiran as an approach to improve aging. Rice kefiran has been reported to improve the intestinal microflora, regulate the intestines, and have anti-aging effects. BioBran has also been reported to have antioxidant effects and improve liver function, and human studies have shown that it affects the diversity of the intestinal microbiota. Quantitative measures of aging that correlate with disease risk are now available through the epigenetic clock test, which examines the entire gene sequence and determines biological age based on the methylation level. Horvath's Clock is the best known of many epigenetic clock tests and was published by Steve Horvath in 2013. In this study, we examine the effect of using Horvath's Clock to improve aging and report on the results, which show a certain effect.

Small extracellular vesicles from young plasma reverse age-related functional declines by improving mitochondrial energy metabolism

Recent investigations into heterochronic parabiosis have unveiled robust rejuvenating effects of young blood on aged tissues. However, the specific rejuvenating mechanisms remain incompletely elucidated. Here we demonstrate that small extracellular vesicles (sEVs) from the plasma of young mice counteract pre-existing aging at molecular, mitochondrial, cellular and physiological levels. Intravenous injection of young sEVs into aged mice extends their lifespan, mitigates senescent phenotypes and ameliorates age-associated functional declines in multiple tissues. Quantitative proteomic analyses identified substantial alterations in the proteomes of aged tissues after young sEV treatment, and these changes are closely associated with metabolic processes. Mechanistic investigations reveal that young sEVs stimulate PGC-1α expression in vitro and in vivo through their miRNA cargoes, thereby improving mitochondrial functions and mitigating mitochondrial deficits in aged tissues. Overall, this study demonstrates that young sEVs reverse degenerative changes and age-related dysfunction, at least in part, by stimulating PGC-1α expression and enhancing mitochondrial energy metabolism.

The biomedical application of inorganic metal nanoparticles in aging and aging-associated diseases

Aging and aging-associated diseases (AAD), including neurodegenerative disease, cancer, cardiovascular diseases, and diabetes, are inevitable process. With the gradual improvement of life style, life expectancy is gradually extended. However, the extended lifespan has not reduced the incidence of disease, and most elderly people are in ill-health state in their later years. Hence, understanding aging and AAD are significant for reducing the burden of the elderly. Inorganic metal nanoparticles (IMNPs) predominantly include gold, silver, iron, zinc, titanium, thallium, platinum, cerium, copper NPs, which has been widely used to prevent and treat aging and AAD due to their superior properties (essential metal ions for human body, easily synthesis and modification, magnetism). Therefore, a systematic review of common morphological alternations of senescent cells, altered genes and signal pathways in aging and AAD, and biomedical applications of IMNPs in aging and AAD is crucial for the further research and development of IMNPs in aging and AAD. This review focus on the existing research on cellular senescence, aging and AAD, as well as the applications of IMNPs in aging and AAD in the past decade. This review aims to provide cutting-edge knowledge involved with aging and AAD, the application of IMNPs in aging and AAD to promote the biomedical application of IMNPs in aging and AAD.

Molecular mechanisms of aging and anti-aging strategies

Aging is a complex and multifaceted process involving a variety of interrelated molecular mechanisms and cellular systems. Phenotypically, the biological aging process is accompanied by a gradual loss of cellular function and the systemic deterioration of multiple tissues, resulting in susceptibility to aging-related diseases. Emerging evidence suggests that aging is closely associated with telomere attrition, DNA damage, mitochondrial dysfunction, loss of nicotinamide adenine dinucleotide levels, impaired macro-autophagy, stem cell exhaustion, inflammation, loss of protein balance, deregulated nutrient sensing, altered intercellular communication, and dysbiosis. These age-related changes may be alleviated by intervention strategies, such as calorie restriction, improved sleep quality, enhanced physical activity, and targeted longevity genes. In this review, we summarise the key historical progress in the exploration of important causes of aging and anti-aging strategies in recent decades, which provides a basis for further understanding of the reversibility of aging phenotypes, the application prospect of synthetic biotechnology in anti-aging therapy is also prospected.

Impact of telomere length and mitochondrial DNA copy number variants on survival of newborn cloned calves

An established technology to create cloned animals is through the use of somatic cell nuclear transfer (SCNT), in which reprogramming the somatic cell nucleus to a totipotent state by enucleated oocyte cytoplasm is a necessary process, including telomere length reprogramming. The limitation of this technology; however, is that the live birth rate of offspring produced through SCNT is significantly lower than that of IVF. Whether and how telomere length play a role in the development of cloned animals is not well understood. Only a few studies have evaluated this association in cloned mice, and fewer still in cloned cows. In this study, we investigated the difference in telomere length as well as the abundance of some selected molecules between newborn deceased cloned calves and normal cows of different ages either produced by SCNT or via natural conception, in order to evaluate the association between telomere length and abnormal development of cloned cows. The absolute telomere length and relative mitochondrial DNA (mtDNA) copy number were determined by real-time quantitative PCR (qPCR), telomere related gene abundance by reverse-transcription quantitative PCR (RT-qPCR), and senescence-associated β-galactosidase (SA-β-gal) expression by SA-β-gal staining. The results demonstrate that the newborn deceased SCNT calves had significantly shortened telomere lengths compared to newborn naturally conceived calves and newborn normal SCNT calves. Significantly lower mtDNA copy number, and significantly lower relative abundance of LMNB1 and TERT, higher relative abundance of CDKN1A, and aberrant SA-β-gal expression were observed in the newborn deceased SCNT calves, consistent with the change in telomere length. These results demonstrate that abnormal telomere shortening, lower mtDNA copy number and abnormal abundance of related genes were specific to newborn deceased SCNT calves, suggesting that abnormally short telomere length may be associated with abnormal development in the cloned calves.

Compliant substrates mitigate the senescence associated phenotype of stress induced mesenchymal stromal cells

Mesenchymal stromal cells (MSCs) are a promising cell population for musculoskeletal cell-based therapies due to their multipotent differentiation capacity and complex secretome. Cells from younger donors are mechanosensitive, evidenced by changes in cell morphology, adhesivity, and differentiation as a function of substrate stiffness in both two- and three-dimensional culture. However, MSCs from older individuals exhibit reduced differentiation potential and increased senescence, limiting their potential for autologous use. While substrate stiffness is known to modulate cell phenotype, the influence of the mechanical environment on senescent MSCs is poorly described. To address this question, we cultured irradiation induced premature senescent MSCs on polyacrylamide hydrogels and assessed expression of senescent markers, cell morphology, and secretion of inflammatory cytokines. Compared to cells on tissue culture plastic, senescent MSCs exhibited decreased markers of the senescence associated secretory phenotype (SASP) when cultured on 50 kPa gels, yet common markers of senescence (e.g., p21, CDKN2A, CDKN1A) were unaffected. These effects were muted in a physiologically relevant heterotypic mix of healthy and senescent MSCs. Conditioned media from senescent MSCs on compliant substrates increased osteoblast mineralization compared to conditioned media from cells on TCP. Mixed populations of senescent and healthy cells induced similar levels of osteoblast mineralization compared to healthy MSCs, further indicating an attenuation of the senescent phenotype in heterotypic populations. These data indicate that senescent MSCs exhibit a decrease in senescent phenotype when cultured on compliant substrates, which may be leveraged to improve autologous cell therapies for older donors.

Bazi Bushen alleviates reproductive aging in aged male mice

Bazi Bushen (BZBS), a traditional Chinese medicine (TCM), has demonstrated therapeutic efficacy in testicular dysfunction within D-galactose and NaNO2 mouse models. This study aimed to ascertain if BZBS could also mitigate the decline in testicular function associated with natural aging. Therefore, male aged mice were employed to evaluate the preventive effects of BZBS on male reproductive aging. This was achieved by assessing sex hormone production, testicular histomorphology, and spermatogenesis. Relative to the untreated aged control group, BZBS administration elevated the levels of sex hormones and spermatocyte populations and preserved normal testicular structure in aged mice. Notably, spermatogenesis was maintained. Further analyses, including malondialdehyde (MDA) assays and real-time PCR, indicated that BZBS diminished testicular oxidative stress and the inflammatory burden. Corroborating these findings, mice treated with BZBS exhibited reductions in the populations of senescent and apoptotic cells within the seminiferous tubules, suggesting alleviated cellular damage. In contrast, we observed that rapamycin, a drug known for its longevity benefits, induced excessive testicular apoptosis and did not decrease lipid peroxidation. Collectively, our results highlight BZBS's promising clinical potential in counteracting male reproductive aging, underlining its mechanisms of action.

The roles of stress-induced premature senescence and Akt/FoxO1 signaling in periapical lesions

OBJECTIVES

There is little knowledge about oxidative stress-induced senescence involvement in apical periodontitis. Here, we explored its molecular mechanism in periapical lesions.

METHODS

Ten cases of radicular cysts and five cases of periapical granulomas were randomly selected. Immunohistochemical analysis was performed to detect the expression and correlation between Senescence-associated factor polymerase I and transcript release factor (PTRF) and Akt/FoxO1 signaling. Human periodontal ligament cells (hPDLCs) pretreated with LY294002 were exposed to H2O2-induced oxidative stress conditions and then cell proliferation, senescence, apoptosis, and associated signaling were evaluated by EdU labeling, β-galactosidase assay, RT-qPCR, and western blot analysis, respectively.

RESULTS

Polymerase I and transcript release factor and Akt/FoxO1 signaling were more frequently expressed in the radicular cyst than in periapical granulomas. Notably, cells in radicular cysts showed Akt activation, FoxO1 phosphorylation, and cytoplasmic translocation. In vitro, prominent H2O2-induced senescence was observed in hPDLCs. LY294002, a PI3K inhibitor, attenuated the expression levels of senescence (Klotho, P16INK4), apoptosis (Bad, Fas), phosphorylated Akt, and phosphorylated FoxO1; however, did not affect cell proliferation.

CONCLUSIONS

Our data indicated that senescence is present in clinical periapical lesions, and Akt/FoxO1 signaling is involved in the H2O2-induced cellular senescence, which could serve as a potential therapeutic target.

OPA1 mutation affects autophagy and triggers senescence in autosomal dominant optic atrophy plus fibroblasts

In several cases of mitochondrial diseases, the underlying genetic and bioenergetic causes of reduced oxidative phosphorylation (OxPhos) in mitochondrial dysfunction are well understood. However, there is still limited knowledge about the specific cellular outcomes and factors involved for each gene and mutation, which contributes to the lack of effective treatments for these disorders. This study focused on fibroblasts from a patient with Autosomal Dominant Optic Atrophy (ADOA) plus syndrome harboring a mutation in the Optic Atrophy 1 (OPA1) gene. By combining functional and transcriptomic approaches, we investigated the mitochondrial function and identified cellular phenotypes associated with the disease. Our findings revealed that fibroblasts with the OPA1 mutation exhibited a disrupted mitochondrial network and function, leading to altered mitochondrial dynamics and reduced autophagic response. Additionally, we observed a premature senescence phenotype in these cells, suggesting a previously unexplored role of the OPA1 gene in inducing senescence in ADOA plus patients. This study provides novel insights into the mechanisms underlying mitochondrial dysfunction in ADOA plus and highlights the potential importance of senescence in disease progression.

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.

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.

SIRT1-dependent PGC-1α deacetylation by SRT1720 rescues progression of atherosclerosis by enhancing mitochondrial function

Vascular smooth muscle cell (VSMC) senescence promotes atherosclerosis via lipid-mediated mitochondrial dysfunction and oxidative stress. However, the mechanisms of mitochondrial dysfunction and VSMC senescence in atherosclerosis have not been established. Here, we investigated the mechanisms whereby signaling pathways regulated by SRT1720 enhance or regulate mitochondrial functions in atherosclerotic VSMCs to suppress atherosclerosis. Initially, we examined the effect of SRT1720 on oleic acid (OA)-induced atherosclerosis. Atherosclerotic VSMCs exhibited elevated expressions of BODIPY and ADRP (adipose differentiation-related protein) and associated intracellular lipid droplet markers. In addition, the expression of collagen I was upregulated by OA, while the expressions of elastin and α-SMA were downregulated. mtDNA copy numbers, an ATP detection assay, transmission electron microscopy (TEM) imaging of mitochondria, mitochondria membrane potentials (assessed using JC-1 probe), and levels of mitochondrial oxidative phosphorylation (OXPHOS) were used to examine the effects of SRT1720 on OA-induced mitochondrial dysfunction. SRT1720 reduced mtDNA damage and accelerated mitochondria repair in VSMCs with OA-induced mitochondria dysfunction. In addition, mitochondrial reactive oxygen species (mtROS) levels were downregulated by SRT1720 in OA-treated VSMCs. Importantly, SRT1720 significantly increased SIRT1 and PGC-1α expression levels, but VSMCs senescence, inflammatory response, and atherosclerosis phenotypes were not recovered by treating cells with EX527 and SR-18292 before SRT1720. Mechanistically, the upregulations of SIRT1 and PGC-1α deacetylation by SRT1720 restored mitochondrial function, and consequently suppressed VSMC senescence and atherosclerosis-associated proteins and phenotypes. Collectively, this study indicates that SRT1720 can attenuate OA-induced atherosclerosis associated with VSMC senescence and mitochondrial dysfunction via SIRT1-mediated deacetylation of the PGC-1α pathway.

Involvement of retinoic acid‑inducible gene‑I in radiation‑induced senescence of human umbilical vein endothelial cells

In 2012, the threshold radiation dose (0.5 Gy) for cardiovascular and cerebrovascular diseases was revised, and this threshold dose may be exceeded during procedures involving radiation such as interventional radiology. Therefore, in addition to regulating radiation dose, it is necessary to develop strategies to prevent and mitigate the development of cardiovascular disease. Cellular senescence is irreversible arrest of cell proliferation. Although cellular senescence is one of the mechanisms for suppressing cancer, it also has adverse effects. For example, senescence of vascular endothelial cells is involved in development of vascular disorders. However, the mechanisms underlying induction of cellular senescence are not fully understood. Therefore, the present study explored the factors involved in the radiation-induced senescence in human umbilical vein endothelial cells (HUVECs). The present study reanalyzed the gene expression data of senescent normal human endothelial cells and fibroblast after irradiation (NCBI Gene Expression Omnibus accession no. GSE130727) and microarray data of HUVECs 24 h after irradiation (NCBI Gene Expression Omnibus accession no. GSE76484). Numerous genes related to viral infection and inflammation were upregulated in radiation-induced senescent cells. In addition, the gene group involved in the retinoic acid-inducible gene-I (RIG-I)-like receptor (RLR) signaling pathway, which plays an important role to induce anti-viral response, was altered in irradiated HUVECs. Therefore, to investigate the involvement of RIG-I and melanoma differentiation-associated gene 5 (MDA5), which are RLRs, in radiation-induced senescence of HUVECs, the protein expression of RIG-I and MDA5 and the activity of senescence-associated β-galactosidase (SA-β-gal), a representative senescence marker, were analyzed. Of note, knockdown of RIG-I in HUVECs significantly decreased radiation-increased proportion of cells with high SA-β-gal activity (i.e., senescent cells), whereas this phenomenon was not observed in MDA5-knockdown cells. Taken together, the present results suggested that RIG-I, but not MDA5, was associated with radiation-induced senescence in HUVECs.

The Molecular Mechanisms in Senescent Cells Induced by Natural Aging and Ionizing Radiation

This review discusses the relationship between cellular senescence and radiation exposure. Given the wide range of ionizing radiation sources encountered by people in professional and medical spheres, as well as the influence of natural background radiation, the question of the effect of radiation on biological processes, particularly on aging processes, remains highly relevant. The parallel relationship between natural and radiation-induced cellular senescence reveals the common aspects underlying these processes. Based on recent scientific data, the key points of the effects of ionizing radiation on cellular processes associated with aging, such as genome instability, mitochondrial dysfunction, altered expression of miRNAs, epigenetic profile, and manifestation of the senescence-associated secretory phenotype (SASP), are discussed. Unraveling the molecular mechanisms of cellular senescence can make a valuable contribution to the understanding of the molecular genetic basis of age-associated diseases in the context of environmental exposure.

The Role of Oxidative Stress in Tumorigenesis and Progression

Oxidative stress refers to the imbalance between the production of reactive oxygen species (ROS) and the endogenous antioxidant defense system. Its involvement in cell senescence, apoptosis, and series diseases has been demonstrated. Advances in carcinogenic research have revealed oxidative stress as a pivotal pathophysiological pathway in tumorigenesis and to be involved in lung cancer, glioma, hepatocellular carcinoma, leukemia, and so on. This review combs the effects of oxidative stress on tumorigenesis on each phase and cell fate determination, and three features are discussed. Oxidative stress takes part in the processes ranging from tumorigenesis to tumor death via series pathways and processes like mitochondrial stress, endoplasmic reticulum stress, and ferroptosis. It can affect cell fate by engaging in the complex relationships between senescence, death, and cancer. The influence of oxidative stress on tumorigenesis and progression is a multi-stage interlaced process that includes two aspects of promotion and inhibition, with mitochondria as the core of regulation. A deeper and more comprehensive understanding of the effects of oxidative stress on tumorigenesis is conducive to exploring more tumor therapies.

Involvement of regulated cell deaths in aging and age-related pathologies

Aging is a pathophysiological process that causes a gradual and permanent reduction in all biological system functions. The phenomenon is caused by the accumulation of endogenous and exogenous damage as a result of several stressors, resulting in significantly increased risks of various age-related diseases such as neurodegenerative diseases, cardiovascular diseases, metabolic diseases, musculoskeletal diseases, and immune system diseases. In addition, aging appears to be connected with mis-regulation of programmed cell death (PCD), which is required for regular cell turnover in many tissues sustained by cell division. According to the recent nomenclature, PCDs are physiological forms of regulated cell death (RCD) useful for normal tissue development and turnover. To some extent, some cell types are connected with a decrease in RCD throughout aging, whereas others are related with an increase in RCD. Perhaps the widespread decline in RCD markers with age is due to a slowdown of the normal rate of homeostatic cell turnover in various adult tissues. As a result, proper RCD regulation requires a careful balance of many pro-RCD and anti-RCD components, which may render cell death signaling pathways more sensitive to maladaptive signals during aging. Current research, on the other hand, tries to further dive into the pathophysiology of aging in order to develop therapies that improve health and longevity. In this scenario, RCD handling might be a helpful strategy for human health since it could reduce the occurrence and development of age-related disorders, promoting healthy aging and lifespan. In this review we propose a general overview of the most recent RCD mechanisms and their connection with the pathophysiology of aging in order to promote targeted therapeutic strategies.

MiR-145-5p overexpression rejuvenates aged adipose stem cells and accelerates wound healing

Adipose-derived stem cells (ADSCs) have been widely applied in translational and regenerative medicine. During aging, there is a recognized functional decline in ADSCs, which compromises their therapeutic effectiveness. Currently, the mechanisms of aging-induced stem cell dysfunction remain unclear, hence there is a need to elucidate these mechanisms and propose strategies for reversing this functional impairment. In this study, we found that ADSCs isolated from old donors (O-ADSCs) presented inferior phenotypes and decreased miR-145-5p levels compared to those from young donors (Y-ADSCs). To interrogate the role of miR-145-5p in ADSCs, gain- and loss-of-function assays were performed. The results indicated that miR-145-5p overexpression in O-ADSCs promoted cellular proliferation and migration, while reducing cell senescence. Further study demonstrated that miR-145-5p could regulate ADSCs function by targeting bone morphogenetic protein binding endothelial cell precursor-derived regulator (BMPER), which is a crucial modulator in angiogenesis. Moreover, in vivo experiments showed that miR-145-5p-overexpressing O-ADSCs accelerated wound healing by promoting wound re-epithelialization and angiogenesis. Collectively, this study indicates that miR-145-5p works as a positive regulator for optimizing O-ADSCs function, and may be a novel therapeutic target for restoring aging-associated impairments in stem cell function.

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.

Effect of Selected Antioxidants on the In Vitro Aging of Human Fibroblasts

The modification of the replicative lifespan (RLS) of fibroblasts is of interest both from a knowledge point of view and for the attenuation of skin aging. The effect of six antioxidants at a concentration of 1 μM on the replicative lifespan of human dermal fibroblasts was studied. The nitroxide 4-hydroxy-TEMPO (TEMPOL), ergothioneine, and Trolox extended the replicative lifespan (RLS) (40 ± 1 population doublings (PD)) by 7 ± 2, 4 ± 1, and 3 ± 1 PD and lowered the expression of p21 at late passages. Coumaric acid, curcumin and resveratrol did not affect the RLS . The level of reactive oxygen species (ROS) was decreased or not affected by the antioxidants although TEMPOL and coumaric acid decreased the level of glutathione. Only ergothioneine and resveratrol decreased the level of protein carbonylation. The antioxidants that could prolong the RLS elevated the mitochondrial membrane potential. Protecting the activity of mitochondria seems to be important for maintaining the replicative capacity of fibroblasts.

Unlocking longevity: the role of telomeres and its targeting interventions

Average life expectancy has been steadily increasing in developed countries worldwide. These demographic changes are associated with an ever-growing social and economic strain to healthcare systems as well as society. The aging process typically manifests as a decline in physiological and cognitive functions, accompanied by a rise in chronic diseases. Consequently, strategies that both mitigate age-related diseases and promote healthy aging are urgently needed. Telomere attrition, characterized by the shortening of telomeres with each cell division, paradoxically serves as both a protective mechanism and a contributor to tissue degeneration and age-related ailments. Based on the essential role of telomere biology in aging, research efforts aim to develop approaches designed to counteract telomere attrition, aiming to delay or reduce age-related diseases. In this review, telomere biology and its role in aging and age-related diseases is summarized along with recent approaches to interfere with telomere shortening aiming at well- and healthy-aging as well as longevity. As aging research enters a new era, this review emphasizes telomere-targeting therapeutics, including telomerase activators and tankyrase inhibitors, while also exploring the effects of antioxidative and anti-inflammatory agents, along with indirectly related approaches like statins.

Prolonged Supplementation of Ozonated Sunflower Oil Bestows an Antiaging Effect, Improves Blood Lipid Profile and Spinal Deformities, and Protects Vital Organs of Zebrafish (Danio rerio) against Age-Related Degeneration: Two-Years Consumption Study

Ozonated sunflower oil (OSO) is renowned for its diverse therapeutic benefits. Nonetheless, the consequences of extended dietary intake of OSO have yet to be thoroughly investigated. Herein, the effect of 2-year dietary supplementation of OSO was examined on the survivability, obesity, skeletal deformities, swimming behavior, and liver, kidney, ovary, and testis function of zebrafish. Results showed that the zebrafish feed supplemented with 20% (wt/wt) OSO for 2 years emerged with higher survivability and body weight management compared to sunflower oil (SO) and normal diet (ND)-supplemented zebrafish. Radio imaging (X-ray)-based analysis revealed 2.6° and 15.2° lower spinal curvature in the OSO-supplemented groups than in the SO and ND-supplemented groups; consistently, OSO-supplemented zebrafish showed better swimming behavior. The histology analysis of the liver revealed the least fatty liver change and interleukin (IL)-6 generation in the OSO-supplemented group. Additionally, a significantly lower level of reactive oxygen species (ROS), apoptotic, and senescent cells were observed in the liver of the OSO-supplemented zebrafish. Also, no adverse effect on the kidney, testis, and ovary morphology was detected during 2 years of OSO consumption. Moreover, lower senescence with diminished ROS and apoptosis was noticed in the kidney and ovary in response to OSO consumption. The OSO supplementation was found to be effective in countering age-associated dyslipidemia by alleviating total cholesterol (TC), triglycerides (TG), low-density lipoproteins (LDL-C) and elevating high-density lipoproteins (HDL-C)/TC levels. Conclusively, prolonged OSO consumption showed no adverse effect on the morphology and functionality of vital organs; in fact, OSO supplementation displayed a protective effect against age-associated detrimental effects on spinal deformities, vital organ functionality, cell senescence, and the survivability of zebrafish.

Design strategies and biological applications of β-galactosidase fluorescent sensor in ovarian cancer research and beyond

Beta-galactosidase (β-galactosidase), a lysosomal hydrolytic enzyme, plays a critical role in the catalytic hydrolysis of glycosidic bonds, leading to the conversion of lactose into galactose. This hydrolytic enzyme is used as a biomarker in various applications, including enzyme-linked immunosorbent assays (ELISAs), gene expression studies, tuberculosis classification, and in situ hybridization. β-Galactosidase abnormalities are linked to various diseases, such as ganglioside deposition, primary ovarian cancer, and cell senescence. Thus, effective detection of β-galactosidase activity may aid disease diagnoses and treatment. Activatable optical probes with high sensitivity, specificity, and spatiotemporal resolution imaging capabilities have become powerful tools for visualization and real time tracking in vivo in the past decade. This manuscript reviews the sensing mechanism, molecular design strategies, and advances of fluorescence probes in the biological application of β-galactosidase, particularly in the field of ovarian cancer research. Current challenges in tracking β-galactosidase and future directions are also discussed.

FBLN5 was Regulated by PRDM9, and Promoted Senescence and Osteogenic Differentiation of Human Periodontal Ligament Stem Cells

OBJECTIVES

Periodontal ligament stem cells (PDLSCs) are ideal seed cells for periodontal tissue regeneration. Our previous studies have indicated that the histone methyltransferase PRDM9 plays an important role in human periodontal ligament stem cells (hPDLSCs). Whether FBLN5, which is a downstream gene of PRDM9, also has a potential impact on hPDLSCs is still unclear.

METHODS

Senescence was assessed using β-galactosidase and Enzyme-linked immunosorbent assay (ELISA). Osteogenic differentiation potential of hPDLSCs was measured through Alkaline phosphatase (ALP) activity assay and Alizarin red detection, while gene expression levels were evaluated using western blot and RT-qPCR analysis.

RESULTS

FBLN5 overexpression promoted the osteogenic differentiation and senescence of hPDLSCs. FBLN5 knockdown inhibited the osteogenic differentiation and senescence of hPDLSCs. Knockdown of PRDM9 decreased the expression of FBLN5 in hPDLSCs and inhibited senescence of hPDLSCs. Additionally, both FBLN5 and PRDM9 promoted the expression of phosphorylated p38 MAPK, Erk1/2 and JNK. The p38 MAPK pathway inhibitor SB203580 and the Erk1/2 pathway inhibitor PD98059 have the same effects on inhibiting the osteogenic differentiation and senescence of hPDLSCs. The JNK pathway inhibitor SP600125 reduced the senescence of hPDLSCs.

CONCLUSION

FBLN5 promoted senescence and osteogenic differentiation of hPDLSCs via activation of the MAPK signaling pathway. FBLN5 was positively targeted by PRDM9, which also activated the MAPK signaling pathway.

Modulation of the HIF-1α-NCOA4-FTH1 Signaling Axis Regulating Ferroptosis-induced Hepatic Stellate Cell Senescence to Explore the Anti-hepatic Fibrosis Mechanism of Curcumol

INTRODUCTION

Senescence of activated hepatic stellate cells (HSC) reduces extracellular matrix expression to reverse liver fibrosis. Ferroptosis is closely related to cellular senescence, but its regulatory mechanisms need to be further investigated. The iron ions weakly bound to ferritin in the cell are called labile iron pool (LIP), and together with ferritin, they maintain cellular iron homeostasis and regulate the cell's sensitivity to ferroptosis.

METHODS

We used lipopolysaccharide (LPS) to construct a pathological model group and divided the hepatic stellate cells into a blank group, a model group, and a curcumol 12.5 mg/L group, a curcumol 25 mg/L group, and a curcumol 50 mg/L group. HIF-1α-NCOA4- FTH1 signalling axis, ferroptosis and cellular senescence were detected by various cellular molecular biology experiments.

RESULT

We found that curcumol could induce hepatic stellate cell senescence by promoting iron death in hepatic stellate cells. Curcumol induced massive deposition of iron ions in hepatic stellate cells by activating the HIF-1α-NCOA4-FTH1 signalling axis, which further led to iron overload and lipid peroxidation-induced ferroptosis. Interestingly, our knockdown of HIF-1α rescued curcumol-induced LIP and iron deposition in hepatic stellate cells, suggesting that HIF-1α is a key target of curcumol in regulating iron metabolism and ferroptosis. We were able to rescue curcumol-induced hepatic stellate cell senescence when we reduced LIP and iron ion deposition using iron chelators.

CONCLUSION

Overall, curcumol induces ferroptosis and cellular senescence by increasing HIF-1α expression and increasing NCOA4 interaction with FTH1, leading to massive deposition of LIP and iron ions, which may be the molecular biological mechanism of its anti-liver fibrosis.

Counteracting diabetes-induced adipose tissue derived-stromal cell senescence

Adipose tissue stromal cells (ADSCs) are prone to functional decline and senescence during metabolic disturbances. In diabetes mellitus (DM), the pathogenic microenvironment induces oxidative stress causing ADSCs to senesce. The senescence associated secretory phenotype (SASP) in turn drives disease progression. The pathogenesis of DM is thus both a cause and consequence of senescence. Therapeutically preventing the onset of senescence in ADSCs may play a significant role in preventing disease progression and directly impact the onset of comorbidities. The purpose of this study was to establish an in vitro model that mimic the DM micro-environment to use as a screening tool to assess the therapeutic efficacy of preventative and restorative agents. Exposing ADSCs ( Collapse

Key Words

• Advanced glycation end products
• Hyperglycemia
• TNFα
• β-galactosidase

Collapse

MESH Headings Collapse

Grants Collapse

Affiliation(s)

Saiuree Govender Experimental Medicine Research Group, Department of Medicine, Faculty of Medicine & Health Sciences, Stellenbosch University, Cape Town, South Africa
Maria Jacoba Kruger Experimental Medicine Research Group, Department of Medicine, Faculty of Medicine & Health Sciences, Stellenbosch University, Cape Town, South Africa
Mari van de Vyver Experimental Medicine Research Group, Department of Medicine, Faculty of Medicine & Health Sciences, Stellenbosch University, Cape Town, South Africa.

Collapse

Proteomic signature profiling in the cortex of dairy cattle unravels the physiology of brain aging

Introduction

Aging is a physiological process occurring in all living organisms. It is characterized by a progressive deterioration of the physiological and cognitive functions of the organism, accompanied by a gradual impairment of mechanisms involved in the regulation of tissue and organ homeostasis, thus exacerbating the risk of developing pathologies, including cancer and neurodegenerative disorders.

Methods

In the present work, for the first time, the influence of aging has been investigated in the brain cortex of the Podolica cattle breed, through LC-MS/MS-based differential proteomics and the bioinformatic analysis approach (data are available via ProteomeXchange with identifier PXD044108), with the aim of identifying potential aging or longevity markers, also associated with a specific lifestyle.

Results and discussion

We found a significant down-regulation of proteins involved in cellular respiration, dendric spine development, synaptic vesicle transport, and myelination. On the other hand, together with a reduction of the neurofilament light chain, we observed an up-regulation of both GFAP and vimentin in the aged samples. In conclusion, our data pave the way for a better understanding of molecular mechanisms underlying brain aging in grazing cattle, which could allow strategies to be developed that are aimed at improving animal welfare and husbandry practices of dairy cattle from intensive livestock.

Cellular microenvironment: a key for tuning mesenchymal stem cell senescence

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

Construction and evaluation of a novel prognostic risk model of aging-related genes in bladder cancer

Background

Bladder cancer (BLCA) is the most common malignancy of the urinary system. Muscle-invasive bladder cancer (MIBC), which constitutes approximately 25% of all BLCA cases, is characterized by frequent recurrence and early onset of metastasis. Bladder cancer most commonly occurs in elderly patients and is significantly associated with aging. However, the prognostic value of age-related genes in BLCA, especially in MIBC, remains unclear.

Materials and methods

Training and testing sets were obtained from The Cancer Genome Atlas BLCA project. Differentially expressed genes between BLCA and normal samples intersected with human aging-related genes. Univariate Cox regression and least absolute shrinkage and selection operator regression analyses were used to identify prognostic aging-related signatures, followed by the construction of a risk score model and nomogram. Kaplan-Meier and receiver operating characteristic analyses were conducted to assess the predictive power. An independent BLCA cohort of 165 samples was included for external validation. The CIBERSORT algorithm was used to explore the characteristics of the immune microenvironment.

Results

Seven genes (IGF1, NGF, GCLM, PYCR1, EFEMP1, APOC3, and IFNB1) were identified by Cox and least absolute shrinkage and selection operator analyses. After combining the gene signature with the clinical parameters of patients with BLCA, a risk-prognosis model and nomogram were constructed and validated with the testing set. Bladder cancer cases with high 7-gene signature scores (high-risk group) and low scores (low-risk group) showed distinct prognoses. Furthermore, 7 types of immune cells were significantly altered between the low- and high-risk groups.

Conclusions

Collectively, our data provide a 7-gene signature that serves as a potential biomarker for BLCA, especially MIBC. Moreover, this 7-gene signature highlights the role of the tumor immune microenvironment in prognosis and thus might be related to the response to anti-programmed cell death protein 1-based immunotherapy.

Zbp1 gene: a modulator of multiple aging hallmarks as potential therapeutic target for age-related diseases

The Zbp1 gene has recently emerged as a potential therapeutic target for age-related diseases. Multiple studies have reported that Zbp1 plays a key role in regulating several aging hallmarks, including cellular senescence, chronic inflammation, DNA damage response, and mitochondrial dysfunction. Regarding cellular senescence, Zbp1 appears to regulate the onset and progression of senescence by controlling the expression of key markers such as p16INK4a and p21CIP1/WAF1. Similarly, evidence suggests that Zbp1 plays a role in regulating inflammation by promoting the production of pro-inflammatory cytokines, such as IL-6 and IL-1β, through activation of the NLRP3 inflammasome. Furthermore, Zbp1 seems to be involved in the DNA damage response, coordinating the cellular response to DNA damage by regulating the expression of genes such as p53 and ATM. Additionally, Zbp1 appears to regulate mitochondrial function, which is crucial for energy production and cellular homeostasis. Given the involvement of Zbp1 in multiple aging hallmarks, targeting this gene represents a potential strategy to prevent or treat age-related diseases. For example, inhibiting Zbp1 activity could be a promising approach to reduce cellular senescence and chronic inflammation, two critical hallmarks of aging associated with various age-related diseases. Similarly, modulating Zbp1 expression or activity could also improve DNA damage response and mitochondrial function, thus delaying or preventing the development of age-related diseases. Overall, the Zbp1 gene appears to be a promising therapeutic target for age-related diseases. In the current review, we have discussed the molecular mechanisms underlying the involvement of Zbp1 in aging hallmarks and proposed to develop effective strategies to target this gene for therapeutic purposes.

Renal function in very old critically ill patients

PURPOSE OF REVIEW

Current demographic change leads to higher number of elderly patients admitted to an ICU. Among other organs also the kidneys show age-related changes, which are associated with a decline in various aspects of renal function. The purpose of this review is to provide an overview of structural and functional changes in elderly and also to specifically address the increased risk of acute kidney injury (AKI) in this population.

RECENT FINDINGS

Ageing in the kidneys is affected by many different factors, such as low grade chronic inflammation, called inflammageing, and various comorbidities. Nevertheless, a decrease of glomerular filtration rate (GFR) occurs independent of the presence of comorbidities and a steady decline of GFR has been reported in both healthy men and women. Pharmacodynamic of many drugs is altered by these changes. Additionally the rate of diuretic resistance appears to be increased. The cause of AKI occurrence in older age is, multifactorial and includes preventable triggers (hypovolemia, hypotension, nephrotoxins) as well as changes associated with aging.

SUMMARY

Age-related alterations of the kidneys were found at microscopic and macroscopic levels of the cell. These changes lead to a reduced renal reserve and subsequently to an increased vulnerability of aged kidneys when an additional stressor is added. Age is an independent risk factor for developing AKI. Physicians should take into account the altered renal function in elderly patients and take renal protective measures at an early stage.

The Protective Effect of Lithium Against Rotenone may be Evolutionarily Conserved: Evidence from Eisenia fetida, a Primitive Animal with a Ganglionic Brain

Chronic exposure to stress is a non-adaptive situation that is associated with mitochondrial dysfunction and the accumulation of reactive oxygen species (ROS), especially superoxide anion (SA). This accumulation of ROS produces damage-associated molecular patterns (DAMPs), which activate chronic inflammatory states and behavioral changes found in several mood disorders. In a previous study, we observed that an imbalance of SA triggered by rotenone (Ro) exposure caused evolutionarily conserved oxi-inflammatory disturbances and behavioral changes in Eisenia fetida earthworms. These results supported our hypothesis that SA imbalance triggered by Ro exposure could be attenuated by lithium carbonate (LC), which has anti-inflammatory properties. The initial protocol exposed earthworms to Ro (30 nM) and four different LC concentrations. LC at a concentration of 12.85 mg/L decreased SA and nitric oxide (NO) levels and was chosen to perform complementary assays: (1) neuromuscular damage evaluated by optical and scanning electron microscopy (SEM), (2) innate immune inefficiency by analysis of Eisenia spp. extracellular neutrophil traps (eNETs), and (3) behavioral changes. Gene expression was also evaluated involving mitochondrial (COII, ND1), inflammatory (EaTLR, AMP), and neuronal transmission (nAchR α5). LC attenuated the high melanized deposits in the circular musculature, fiber disarrangement, destruction of secretory glands, immune inefficiency, and impulsive behavior pattern triggered by Ro exposure. However, the effects of LC and Ro on gene expression were more heterogeneous. In summary, SA imbalance, potentially associated with mitochondrial dysfunction, appears to be an evolutionary component triggering oxidative, inflammatory, and behavioral changes observed in psychiatric disorders that are inhibited by LC exposure.

Therapy-induced senescence as a component of tumor biology: Evidence from clinical cancer

Therapy-Induced Senescence (TIS) is an established response to anticancer therapy in a variety of cancer models. Ample evidence has characterized the triggers, hallmarks, and functional outcomes of TIS in preclinical studies; however, limited evidence delineates TIS in clinical cancer (human tumor samples). We examined the literature that investigated the induction of TIS in samples derived from human cancers and highlighted the major findings that suggested that TIS represents a main constituent of tumor biology. The most frequently utilized approach to identify TIS in human cancers was to investigate the protein expression of senescence-associated markers (such as cyclins, cyclin-dependent kinase inhibitors, Ki67, DNA damage repair response markers, DEC1, and DcR1) via immunohistochemical techniques using formalin-fixed paraffin-embedded (FFPE) tissue samples and/or testing the upregulation of Senescence-Associated β-galactosidase (SA-β-gal) in frozen sections of unfixed tumor samples. Collectively, and in studies where the extent of TIS was determined, TIS was detected in 31-66% of tumors exposed to various forms of chemotherapy. Moreover, TIS was not only limited to both malignant and non-malignant components of tumoral tissue but was also identified in samples of normal (non-transformed) tissue upon chemo- or radiotherapy exposure. Nevertheless, the available evidence continues to be limited and requires a more rigorous assessment of in vivo senescence based on novel approaches and more reliable molecular signatures. The accurate assessment of TIS will be beneficial for determining its relevant contribution to the overall outcome of cancer therapy and the potential translatability of senotherapeutics.

Exposure to Polystyrene Nanoplastics Led to Learning and Memory Deficits in Zebrafish by Inducing Oxidative Damage and Aggravating Brain Aging

Nanoplastics (NPs) may pass through the blood-brain barrier, giving rise to serious concerns about their potential toxicity to the brain. In this study, the effects of NPs exposure on learning and memory, the primary cognitive functions of the brain, are assessed in zebrafish with classic T-maze exploration tasks. Additionally, to reveal potential affecting mechanisms, the impacts of NPs exposure on brain aging, oxidative damage, energy provision, and the cell cycle are evaluated. The results demonstrate that NP-exposed zebrafish takes significantly longer for their first entry and spends markedly less time in the reward zone in the T-maze task, indicating the occurrence of learning and memory deficits. Moreover, higher levels of aging markers (β-galactosidase and lipofuscin) are detected in the brains of NP-exposed fish. Along with the accumulation of reactive free radicals, NP-exposed zebrafish suffer significant levels of brain oxidative damage. Furthermore, lower levels of Adenosine triphosphate (ATP) and cyclin-dependent kinase 2 and higher levels of p53 are observed in the brains of NP-exposed zebrafish, suggesting that NPs exposure also results in a shortage of energy supply and an arrestment of the cell cycle. These findings suggest that NPs exposure may pose a severe threat to brain health, which deserves closer attention.

Understanding cellular senescence: pathways involved, therapeutics and longevity aiding

A normal somatic cell undergoes cycles of finite cellular divisions. The presence of surveillance checkpoints arrests cell division in response to stress inducers: oxidative stress from excess free radicals, oncogene-induced abnormalities, genotoxic stress, and telomere attrition. When facing such stress when undergoing these damages, there is a brief pause in the cell cycle to enable repair mechanisms. Also, the nature of stress determines whether the cell goes for repair or permanent arrest. As the cells experience transient or permanent stress, they subsequently choose the quiescence or senescence stage, respectively. Quiescence is an essential stage that allows the arrested/damaged cells to go through appropriate repair mechanisms and then revert to the mainstream cell cycle. However, senescent cells are irreversible and accumulate with age, resulting in inflammation and various age-related disorders. In this review, we focus on senescence-associated pathways and therapeutics understanding cellular senescence as a cascade that leads to aging, while discussing the recent details on the molecular pathways involved in regulating senescence and the benefits of therapeutic strategies against accumulated senescent cells and their secretions.

Functional Role of Taurine in Aging and Cardiovascular Health: An Updated Overview

Taurine, a naturally occurring sulfur-containing amino acid, has attracted significant attention in recent years due to its potential health benefits. Found in various foods and often used in energy drinks and supplements, taurine has been studied extensively to understand its impact on human physiology. Determining its exact functional roles represents a complex and multifaceted topic. We provide an overview of the scientific literature and present an analysis of the effects of taurine on various aspects of human health, focusing on aging and cardiovascular pathophysiology, but also including athletic performance, metabolic regulation, and neurological function. Additionally, our report summarizes the current recommendations for taurine intake and addresses potential safety concerns. Evidence from both human and animal studies indicates that taurine may have beneficial cardiovascular effects, including blood pressure regulation, improved cardiac fitness, and enhanced vascular health. Its mechanisms of action and antioxidant properties make it also an intriguing candidate for potential anti-aging strategies.

Quantitative biochemical phenotypic heterogeneity of senescent macrophage at a single cell level by Synchrotron Radiation Fourier Transform Infrared Microspectroscopy

Macrophage senescence plays an important role in pathophysiological process of age-related diseases such as atherosclerosis, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, and lung cancer. After macrophage senescence, the biochemical phenotypes related to biological functions showed great heterogeneity. However, the biochemical phenotype and phenotypic heterogeneity of senescent macrophage has not been fully understood. Exploring the phenotype of biochemical substances in senescent macrophage will be helpful for understanding the function of senescent macrophage and finding out the potential mechanism between immune macrophage senescence and age-related diseases. In this study, we employed SR-FTIR microspectroscopy to detect the biochemical phenotype and phenotypic heterogeneity of single macrophage. The whole infrared spectra of senescent macrophages shifted, indicating biochemical substance changes within senescent macrophages. PCA and intercellular Euclidean distance statistical analysis based on specific spectra regions revealed dynamic changes of lipids and proteins during macrophage senescence. This proved that SR-FTIR microspectroscopy is an effective tool to detect the single cell biochemical phenotype transformation and phenotypic heterogeneity during macrophage senescence. It is of great significance to provide an evaluation method or clue for the study of cellular functions related to intracellular biochemical substances.

Contribution of viral and bacterial infections to senescence and immunosenescence

Cellular senescence is a key biological process characterized by irreversible cell cycle arrest. The accumulation of senescent cells creates a pro-inflammatory environment that can negatively affect tissue functions and may promote the development of aging-related diseases. Typical biomarkers related to senescence include senescence-associated β-galactosidase activity, histone H2A.X phosphorylation at serine139 (γH2A.X), and senescence-associated heterochromatin foci (SAHF) with heterochromatin protein 1γ (HP-1γ protein) Moreover, immune cells undergoing senescence, which is known as immunosenescence, can affect innate and adaptative immune functions and may elicit detrimental effects over the host's susceptibility to infectious diseases. Although associations between senescence and pathogens have been reported, clear links between both, and the related molecular mechanisms involved remain to be determined. Furthermore, it remains to be determined whether infections effectively induce senescence, the impact of senescence and immunosenescence over infections, or if both events coincidently share common molecular markers, such as γH2A.X and p53. Here, we review and discuss the most recent reports that describe cellular hallmarks and biomarkers related to senescence in immune and non-immune cells in the context of infections, seeking to better understand their relationships. Related literature was searched in Pubmed and Google Scholar databases with search terms related to the sections and subsections of this review.

Oxidative stress in intervertebral disc degeneration: Molecular mechanisms, pathogenesis and treatment

Low back pain (LBP) is a leading cause of labour loss and disability worldwide, and it also imposes a severe economic burden on patients and society. Among symptomatic LBP, approximately 40% is caused by intervertebral disc degeneration (IDD). IDD is the pathological basis of many spinal degenerative diseases such as disc herniation and spinal stenosis. Currently, the therapeutic approaches for IDD mainly include conservative treatment and surgical treatment, neither of which can solve the problem from the root by terminating the degenerative process of the intervertebral disc (IVD). Therefore, further exploring the pathogenic mechanisms of IDD and adopting targeted therapeutic strategies is one of the current research hotspots. Among the complex pathophysiological processes and pathogenic mechanisms of IDD, oxidative stress is considered as the main pathogenic factor. The delicate balance between reactive oxygen species (ROS) and antioxidants is essential for maintaining the normal function and survival of IVD cells. Excessive ROS levels can cause damage to macromolecules such as nucleic acids, lipids, and proteins of cells, affect normal cellular activities and functions, and ultimately lead to cell senescence or death. This review discusses the potential role of oxidative stress in IDD to further understand the pathophysiological processes and pathogenic mechanisms of IDD and provides potential therapeutic strategies for the treatment of IDD.

Evaluation of the Effectiveness of an Innovative Polycomponent Formulation on Adult and Aged Human Dermal Fibroblasts

Skin aging is a dynamic process that determines structural alterations in ECM and reduction in dermal fibroblasts. The recent availability on the market of an innovative polycomponent formulation (KARISMA Rh Collagen® FACE, K) containing noncrosslinked high-molecular-weight hyaluronic acid (HMW-HA), a human recombinant polypeptide of collagen-1 alpha chain, and carboxymethyl cellulose (CMC), attracted our scientific interest in evaluating its biomolecular effects on human dermal adult and aged fibroblasts. After treatment with increasing K concentrations, cell proliferation, collagen I, prolyl 4-hydroxylase (P4HA1), an essential protein in collagen biosynthesis, and α-SMA levels were assessed. The fibroblast contractility, TGF-β1 levels, and oxidative stress markers were also evaluated. K formulation exposure led to a significant and dose-dependent increase in the proliferation and migration of adult fibroblasts. Of note, the K exposure counteracted the H2O2-induced aging by promoting cell proliferation, reducing β-galactosidase activity, and neutralizing the aging-associated oxidative damage. Moreover, an increase in collagen I, P4HA1, α-SMA, TGF-β1 levels, and improved contractility of adult and aged fibroblasts were observed after treatment. Overall, our results show evidence that the K treatment is efficacious in improving biological functions in adult fibroblasts and suppressing the biomolecular events associated with H2O2-induced cellular aging, thus supporting the regenerative and bio-revitalizing action of the K formulation helpful in preventing or treating skin aging.

Molecularly Targeted Fluorescent Sensors for Visualizing and Tracking Cellular Senescence

Specific identification and monitoring of senescent cells are essential for the in-depth understanding and regulation of senescence-related life processes and diseases. Fluorescent sensors providing real-time and in situ information with spatiotemporal resolution are unparalleled tools and have contributed greatly to this field. This review focuses on the recent progress in fluorescent sensors for molecularly targeted imaging and real-time tracking of cellular senescence. The molecular design, sensing mechanisms, and biological activities of the sensors are discussed. The sensors are categorized by the types of markers and targeting ligands. Accordingly, their molecular recognition and fluorescent performance towards senescence biomarkers are summarized. Finally, the perspective and challenges in this field are discussed, which are expected to assist future design of next-generation sensors for monitoring cellular senescence.