Lamivudine modulates the expression of neurological impairment-related genes and LINE-1 retrotransposons in brain tissues of a Down syndrome mouse model.

Elevated activity of retrotransposons is increasingly recognized to be implicated in a wide range of neurodegenerative and neurodevelopmental diseases, including Down syndrome (DS), which is the most common chromosomal condition causing intellectual disability globally. Previous research by our group has revealed that treatment with lamivudine, a reverse transcriptase inhibitor, improved neurobehavioral phenotypes and completely rescued hippocampal-dependent recognition memory in a DS mouse model, Ts65Dn. We hypothesized that retrotransposition rates would increase in the Ts65Dn mouse model, and lamivudine could block retrotransposons. We analyzed the differentially expressed long interspersed element-1 (LINE-1 or L1) mapping on MMU16 and 17, and showed for the first time that retrotransposition could be associated with Ts65Dn's pathology, as misregulation of L1 was found in brain tissues associated with trisomy. In the cerebral cortex, 6 out of 26 upregulated L1s in trisomic treated mice were located in the telomeric region of MMU16 near Ttc3, Kcnj6, and Dscam genes. In the hippocampus, one upregulated L1 element in trisomic treated mice was located near the Fgd4 gene on MMU16. Moreover, two downregulated L1s rescued after treatment with lamivudine were located in the intronic region of Nrxn1 (MMU17) and Snhg14 (MMU7), implicated in a variety of neurodegenerative disorders. To gain further insight into the mechanism of this improvement, we here analyzed the gene expression profile in the hippocampus and cerebral cortex of trisomic mice treated and no-treated with lamivudine compared to their wild-type littermates. We found that treatment with lamivudine rescued the expression of 24% of trisomic genes in the cortex (located on mouse chromosome (MMU) 16 and 17) and 15% in the hippocampus (located in the human chromosome 21 orthologous regions), with important DS candidate genes such as App and Ets2, rescued in both regions.

Senescence detection using reflected light.

Senescence is an important cellular program occurring in development, tissue repair, cancer, and aging. Increased senescence is also associated with disease states, including obesity and Type 2 diabetes (T2D). Characterizing and quantifying senescent cells at a single cell level has been challenging and particularly difficult in large primary cells, such as human adipocytes. In this study, we present a novel approach that utilizes reflected light for accurate senescence-associated beta-galactosidase (SABG) staining measurements, which can be integrated with immunofluorescence and is compatible with primary mature adipocytes from both human and mouse, as well as with differentiated 3T3-L1 cells. This technique provides a more comprehensive classification of a cell's senescent state by incorporating multiple criteria, including robust sample-specific pH controls. By leveraging the precision of confocal microscopy to detect X-gal crystals using reflected light, we achieved superior sensitivity over traditional brightfield techniques. This strategy allows for the capture of all X-gal precipitates in SABG-stained samples, revealing diverse X-gal staining patterns and improved detection sensitivity. Additionally, we demonstrate that reflected light outperforms western blot analysis for the detection and quantification of senescence in mature human adipocytes, as it offers a more accurate representation of SABG activity. This detection strategy enables a more thorough investigation of senescent cell characteristics and specifically a deeper look at the relationship between adipocyte senescence and obesity associated disorders, such as T2D.

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.

Effect of physical activity in lymphocytes senescence burden in COPD patients.

Chronic obstructive pulmonary disease (COPD) is regarded as an accelerated-age disease in which chronic inflammation, maladaptive immune responses and senescence cell burden coexist. Accordingly, cellular senescence has emerged as a potential mechanism involved in COPD pathophysiology. In this study, 25 stable COPD patients underwent a daily physical activity promotion program for six months. We reported that increase of physical activity was related to a reduction of the senescent cell burden in COPD patients' circulating lymphocytes. Senescent T-lymphocytes population, characterized by absence of surface expression of CD28, was reduced after physical activity intervention and the reduction was associated to the increase of physical activity level. In addition, the mRNA expression of cyclin-dependent kinases inhibitors, a hallmark of cell senescence, was reduced and, in accordance, the proliferative capacity of lymphocytes was improved post-intervention. Moreover, we observed an increase in functionality in T-cells from patients after intervention, including improved markers of activation, enhanced cytotoxicity and altered cytokines secretions in response to viral challenge. Lastly, physical activity intervention reduced the potential of lymphocytes' secretome to induce senescence in human primary fibroblasts. In conclusion, our study provides, for the first time, evidence of the potential of physical activity intervention in COPD patients to reduce the senescent burden in circulating immune cells.

Endothelin-1 (ET-1) contributes to senescence and phenotypic changes in brain pericytes in diabetes-mimicking conditions.

Diabetes mediates endothelial dysfunction and increases the risk of Alzheimer's Disease & Related Dementias. Diabetes also dysregulates the ET system. ET-1-mediated constriction of brain microvascular pericytes (BMVPCs) has been shown to contribute to brain hypoperfusion. Cellular senescence, a process that arrests the proliferation of harmful cells, instigates phenotypical changes and proinflammatory responses in endothelial cells that impact their survival and function. Thus, we hypothesized that ET-1 mediates BMVPC senescence and phenotypical changes in diabetes-like conditions. Human BMVPCs were incubated in diabetes-like conditions with or without ET-1 (1 µmol/L) for 3 and 7 days. Hydrogen peroxide (100 µmol/L H2O2) was used as a positive control for senescence and to mimic ischemic conditions. Cells were stained for senescence-associated ß-galactosidase or processed for immunoblotting and quantitative real-time PCR analyses. In additional experiments, cells were stimulated with ET-1 in the presence or absence of ETA receptor antagonist BQ-123 (20 µmol/L) or ETB receptor antagonist BQ-788 (20 µmol/L). ET-1 stimulation increased ß-galactosidase accumulation which was prevented by BQ-123. ET-1 also increased traditional senescence marker p16 protein and pericyte-specific senescence markers, TGFB1i1, PP1CA, and IGFBP7. Furthermore, ET-1 stimulated contractile protein α-SMA and microglial marker ostepontin in high glucose suggesting a shift toward an ensheathing or microglia-like phenotype. In conclusion, ET-1 triggers senescence, alters ETA and ETB receptors, and causes phenotypical changes in BMVPCs under diabetes-like conditions. These in vitro findings need to be further studied in vivo to establish the role of ETA receptors in the progression of pericyte senescence and phenotypical changes in VCID.

Senotherapy preserves resilience in aging.

In aging societies, social and economic burdens of aging-related diseases are increasing significantly. Senotherapy, which targets aging by eliminating senescent cells (senolytics) or removing sources of chronic inflammation (senostatics), are proposed as novel strategies for aging-related diseases. Aged or frail people suffer a decline of tissue reserve capacity during aging. Resilience, which is much reduced in older people, is essential for recovery from diseases, stresses or crises. Impaired resilience is one of the reasons why aged people experience a gradual waning of their daily activity and an increase of multimorbidity. Calorie restriction results in senostatic alleviation of chronic inflammation, whereas senolytic drugs induce apoptosis of senescent cells, which exacerbate aging by excreting inflammatory factors. Thus, both senolytics and senostatics are expected to reduce sterile inflammation, originating from senescent cells. Geriatr Gerontol Int 2024; ••: ••-••.

Transcriptomic analyses of lung tissues reveal key genes associated with progression of systemic sclerosis-interstitial lung disease (SSc-ILD).

OBJECTIVE: Systemic sclerosis-interstitial lung disease (SSc-ILD) is the leading cause of death in SSc, affecting around 50 % of the patients. Lung tissue of patients with early-stage SSc-ILD is characterized by a predominant inflammatory response with inconspicuous fibrosis, which may progress to honeycombing fibrosis. Hence, a better understanding of the molecular mechanisms underpinning SSc-ILD pathogenesis is needed to improve treatment options and progression prediction. This transcriptomic study aims to reveal the differential gene expression between control (ctrl) lung tissue and inflammatory, prefibrotic and fibrotic lung tissue to capture progression of early to late phase SSc-ILD. METHODS: Twelve explanted lungs from patients with SSc-ILD were used to analyze gene expression from formalin-fixed paraffin-embedded lung tissues with varying stages of ILD (n = 18) and control lung tissue (n = 6). The SSc-ILD tissues were stratified into three ROIs: inflammatory, prefibrotic, and fibrotic using histological assessments to define a longitudinal simulation of early to late phases of SSc-ILD. The nanoString (nS) nCounter Human Fibrosis Panel was used to profile the transcriptome in the regions of interest. Validation of potential targetswas performed with immunohistochemistry in the same tissues that were used for transcriptome analysis. RESULTS: To validate our simulation model, we performed subgroup analysis that showed an incremental increase in pathway scores related to the severity of fibrosis. Ctrl vs SSc-ILD comparison demonstrated 24 differentially expressed genes, two of which had the most pronounced p-values. Cyclin-dependent kinase inhibitor (cdkn2c) was overexpressed (P = 0.00052) in SSc-ILD compared to ctrl, while expression of Pellino E3 ubiquitin-protein ligase 1 (peli1) showed lower expression (P = 0.0012). Additionally, in all four groups, cdkn2c and peli1 gene expression showed an incremental increase and decrease, respectively. Immunohistochemistry of cdkn2c showed consistent results with the nS analysis. CONCLUSION: More cdkn2c and less peli1 expression were associated with more advanced stages of SSc-ILD on histologic assessment. We report the potential of the cell cycle inhibitor and senescence marker, cdkn2c (p18) to be associated with fibrosis progression.

Exploring the link between dystrophic microglia and the spread of Alzheimer's neuropathology.

Genetics and other data modalities indicate that microglia play a critical role in Alzheimer's disease (AD) progression, but details of microglia's disease-driving influence are poorly understood. Microglial cells can be parsed into subtypes based on their histologic appearance. One microglia subtype, termed dystrophic microglia, is characterised structurally by fragmented processes and cytoplasmic decay, and their presence has been associated with ageing and neurodegeneration. Recent studies suggest that the interaction between tau proteins and amyloid-ß might induce dystrophic changes in microglia, potentially linking amyloid-ß and tau pathologies to their effects on these microglia. We developed a study of human brains to test the hypothesis that dystrophic microglia are involved in AD progression. We speculated that if their presence is unique to AD neuropathologic change (ADNC), they would be substantially more common in ADNC than in neurodegenerative diseases characterised by other proteinopathies, e.g., α-synuclein or TDP-43 pathology. Our analyses used histologically stained sections from five human brain regions of 64 individuals across six disease states, from healthy controls to advanced AD stages, including comparative conditions such as Lewy Body Disease (LBD) and limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC). Using stereological sampling and digital pathology, we assessed ramified, hypertrophic, and dystrophic microglia populations. We found a significant increase in dystrophic microglia in areas early affected by ADNC, suggesting a disease-specific role in neuropathology. Mediation analysis and structural equation modelling suggest dystrophic microglia may impact the regional spread of ADNC. In the mediation model, tau was found to be the initiating factor leading to the development of dystrophic microglia, which then was associated with the spread of amyloid-ß and tau. These results suggest that a loss of microglia's protective role could contribute to the spread of ADNC and indicate that further research into preserving microglial function may be warranted.

Crosstalk between the DNA damage response and cellular senescence drives aging and age-related diseases.

Cellular senescence is a crucial process of irreversible cell-cycle arrest, in which cells remain alive, but permanently unable to proliferate in response to distinct types of stressors. Accumulating evidence suggests that DNA damage builds over time and triggers DNA damage response signaling, leading to cellular senescence. Cellular senescence serves as a platform for the perpetuation of inflammatory responses and is central to numerous age-related diseases. Defects in DNA repair genes or senescence can cause premature aging disease. Therapeutic approaches limiting DNA damage or senescence contribute to a rescued phenotype of longevity and neuroprotection, thus suggesting a mechanistic interaction between DNA damage and senescence. Here, we offer a unique perspective on the crosstalk between the DNA damage response pathway and senescence as well as their contribution to age-related diseases. We further summarize recent progress on the mechanisms and therapeutics of senescence, address existing challenges, and offering new insights and future directions in the senescence field.

Curcumin analogue EF24 prevents alveolar epithelial cell senescence to ameliorate idiopathic pulmonary fibrosis via activation of PTEN.

BACKGROUND: Treating Idiopathic pulmonary fibrosis (IPF) remains challenging owing to its relentless progression, grim prognosis, and the scarcity of effective treatment options. Emerging evidence strongly supports the critical role of accelerated senescence in alveolar epithelial cells (AECs) in driving the progression of IPF. Consequently, targeting senescent AECs emerges as a promising therapeutic strategy for IPF. PURPOSE: Curcumin analogue EF24 is a derivative of curcumin and shows heightened bioactivity encompassing anti-inflammatory, anti-tumor and anti-aging properties. The objective of this study was to elucidate the therapeutic potential and underlying molecular mechanisms of EF24 in the treatment of IPF. METHODS: A549 and ATII cells were induced to become senescent using bleomycin. Senescence markers were examined using different methods including senescence-associated ß-galactosidase (SA-ß-gal) staining, western blotting, and q-PCR. Mice were intratracheally administrated with bleomycin to induce pulmonary fibrosis. This was validated by micro-computed tomography (CT), masson trichrome staining, and transmission electron microscope (TEM). The role and underlying mechanisms of EF24 in IPF were determined in vitro and in vivo by evaluating the expressions of PTEN, AKT/mTOR/NF-κB signaling pathway, and mitophagy using western blotting or flow cytometry. RESULTS: We identified that the curcumin analogue EF24 was the most promising candidate among 12 compounds against IPF. EF24 treatment significantly reduced senescence biomarkers in bleomycin-induced senescent AECs, including SA-ß-Gal, PAI-1, P21, and the senescence-associated secretory phenotype (SASP). EF24 also effectively inhibited fibroblast activation which was induced by senescent AECs or TGF-ß. We revealed that PTEN activation was integral for EF24 to inhibit AECs senescence by suppressing the AKT/mTOR/NF-κB signaling pathway. Additionally, EF24 improved mitochondrial dysfunction through induction of mitophagy. Furthermore, EF24 administration significantly reduced the senescent phenotype induced by bleomycin in the lung tissues of mice. Notably, EF24 mitigates fibrosis and promotes overall health benefits in both the acute and chronic phases of IPF, suggesting its therapeutic potential in IPF treatment. CONCLUSION: These findings collectively highlight EF24 as a new and effective therapeutic agent against IPF by inhibiting senescence in AECs.

Radix rehmanniae praeparata extracts ameliorate hepatic ischemia-reperfusion injury by reversing LRP1-NOTCH1-C/EBPß 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/EBPß pathways. Additionally, the specific inhibition of NOTCH1 by siRNA synergistically enhanced the hepatoprotective effect of RRPGLY. The ChIP-qPCR results further showed that C/EBPß was enriched at the promoter of a representative SASP, Il-1ß, 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.

TRAP1 drives smooth muscle cell senescence and promotes atherosclerosis via HDAC3-primed histone H4 lysine 12 lactylation.

BACKGROUND AND AIMS: Vascular smooth muscle cell (VSMC) senescence is crucial for the development of atherosclerosis, characterized by metabolic abnormalities. Tumour necrosis factor receptor-associated protein 1 (TRAP1), a metabolic regulator associated with ageing, might be implicated in atherosclerosis. As the role of TRAP1 in atherosclerosis remains elusive, this study aimed to examine the function of TRAP1 in VSMC senescence and atherosclerosis. METHODS: TRAP1 expression was measured in the aortic tissues of patients and mice with atherosclerosis using western blot and RT-qPCR. Senescent VSMC models were established by oncogenic Ras, and cellular senescence was evaluated by measuring senescence-associated ß-galactosidase expression and other senescence markers. Chromatin immunoprecipitation (ChIP) analysis was performed to explore the potential role of TRAP1 in atherosclerosis. RESULTS: VSMC-specific TRAP1 deficiency mitigated VSMC senescence and atherosclerosis via metabolic reprogramming. Mechanistically, TRAP1 significantly increased aerobic glycolysis, leading to elevated lactate production. Accumulated lactate promoted histone H4 lysine 12 lactylation (H4K12la) by down-regulating the unique histone lysine delactylase HDAC3. H4K12la was enriched in the senescence-associated secretory phenotype (SASP) promoter, activating SASP transcription and exacerbating VSMC senescence. In VSMC-specific Trap1 knockout ApoeKO mice (ApoeKOTrap1SMCKO), the plaque area, senescence markers, H4K12la, and SASP were reduced. Additionally, pharmacological inhibition and proteolysis-targeting chimera (PROTAC)-mediated TRAP1 degradation effectively attenuated atherosclerosis in vivo. CONCLUSIONS: This study reveals a novel mechanism by which mitonuclear communication orchestrates gene expression in VSMC senescence and atherosclerosis. TRAP1-mediated metabolic reprogramming increases lactate-dependent H4K12la via HDAC3, promoting SASP expression and offering a new therapeutic direction for VSMC senescence and atherosclerosis.

Senescence in Alveolar Epithelial Type II Cells Promotes Acute Lung Injury and Impairs Regeneration.

Mortality of acute lung injury (ALI) increases with age. Alveolar epithelial type 2 cells (AEII) are the progenitor cells of the alveolar epithelium and crucial for repair after injury. We hypothesize that telomere dysfunction-mediated AEII senescence impairs regeneration and promotes the development of ALI. To discriminate between the impact of old age and AEII senescence in ALI, young (3 months) and old (18 months) Sftpc-Ai9 mice and young Sftpc-Ai9-Trf1 mice with inducible Trf1 knockout-mediated senescence in AEII were treated with 1 µg lipopolysaccharide (LPS)/g BW (n=9-11). Control mice received saline (n=7). Mice were sacrificed 4 or 7 days later. Lung mechanics, pulmonary inflammation and proteomes were analyzed and parenchymal injury, AEII proliferation and AEI differentiation rate were quantified using stereology. Old mice showed 55% mortality by day 4, whereas all young mice survived. Pulmonary inflammation was most severe in old mice, followed by Sftpc-Ai9-Trf1 mice. Young Sftpc-Ai9 mice recovered almost completely by day 7, while Sftpc-Ai9-Trf1 mice still showed mild signs of injury. An expansion of AEII was only measured in young Sftpc-Ai9 mice at day 7. Aging and telomere dysfunction-mediated senescence had no impact on AEI differentiation rate in controls, but the reduced number of AEII in Sftpc-Ai9-Trf1 mice also affected de-novo differentiation after injury. In conclusion, telomere dysfunction-mediated AEII senescence promoted parenchymal inflammation in ALI, but did not enhance mortality like old age. While Differentiation rate remained functional with old age and AEII senescence, AEII proliferative capacity was impaired in ALI, affecting the regenerative ability.

Metformin suppresses esophageal cancer progression through the radiation­induced cellular senescence of cancer­associated fibroblasts.

Senescent cells are known to secrete proteins, including inflammatory cytokines and damage­associated molecular patterns. This phenomenon is known as the senescence­associated secretory phenotype (SASP). SASP in cancer stromal fibroblasts is involved in cancer growth and progression. Conversely, metformin, an antidiabetic drug, has been reported to inhibit SASP induction by inhibiting the activation of NF­κB, a regulator of SASP. To date, at least to the best of our knowledge, there have been no reports regarding cellular senescence in fibroblasts and tumor progression via the SASP­mediated paracrine pathway. The present study thus aimed to elucidate the induction mechanisms of SASP in radiation­induced fibroblasts and to determine its effects on cancer progression via the paracrine pathway. Furthermore, the present study aimed to determine whether controlling SASP using metformin suppresses cancer progression. A well­differentiated esophageal cancer cell line established by the authors' department and fibroblasts isolated and cultured from the non­cancerous esophageal mucosa of resected esophageal cancer cases were used for the experiments. Fibroblasts were irradiated with 8 Gy radiation, and the changes in the expression of the senescence markers, SA­ß­gal, p21, p16 and NF­κB were evaluated using immunofluorescent staining and western blot analysis in the presence or absence of metformin treatment. The culture supernatants of irradiated fibroblasts treated with metformin and those treated without metformin were collected and added to the cancer cells to evaluate their proliferative, invasive and migratory abilities. Vimentin and E­cadherin expression levels were also evaluated using immunofluorescent staining and western blot analysis. The expression levels of p16, p21 and NF­κB in irradiated fibroblasts were attenuated by treatment with metformin. Supernatants collected from irradiated fibroblasts exhibited the proliferative activity of esophageal cancer cells, and the promotion of migratory and invasion abilities, which may be due to epithelial­mesenchymal transition and changes in cell morphology. These reactions were confirmed to be suppressed by the addition of the supernatant of cultured fibroblasts pre­treated with metformin. On the whole, the present study demonstrates that fibroblasts in the cancer stroma may be involved in tumor progression through cellular senescence.

Rapamycin Attenuates H2O2-Induced Oxidative Stress-Related Senescence in Human Skin Fibroblasts.

BACKGROUND: Oxidative stress plays an important role in the skin aging process. Rapamycin has been shown to have anti-aging effects, but its role in oxidative senescence of skin cells remains unclear. The aim of this study was to explore the effect of rapamycin on oxidative stress-induced skin cell senescence and to illustrate the mechanism. METHODS: Primary human skin fibroblasts (HSFs) were extracted and a model of H2O2-induced oxidative senescence was constructed, and the effects of rapamycin on their value-added and migratory capacities were detected by CCK-8 and scratch assays. SA-ß-gal was utilized to detect senescence, oxidatively closely related factors were also assessed. Gene and protein expressions of senescence, oxidative, and autophagy were detected by western blotting and quantitative-PCR. The data were analyzed by one-way analysis of variance. RESULTS: Rapamycin (0.1 nmol/L for 48 h) promoted the proliferative and migration of H2O2-treated HSFs (p < 0.05), decreased senescent phenotypes SA-ß-gal staining and the expression of P53, and MMP-1 proteins, and increased the expression level of COL1A-1 (p < 0.001). Rapamycin also enhanced the activities of SOD and HO-1, and effectively removed intracellular ROS, MDA levels (p < 0.05), in addition, autophagy-related proteins and genes were significantly elevated after rapamycin pretreatment (p < 0.001). Rapamycin upregulated the autophagy pathway to exert its protective effects. CONCLUSION: Our findings indicate that rapamycin shields HSFs from H2O2-induced oxidative damage, the mechanism is related to the reduction of intracellular peroxidation and upregulation of autophagy pathway. Therefore, rapamycin has the potential to be useful in the investigation and prevention of signs of aging and oxidative stress.

Characteristics and mechanisms of T-cell senescence: A potential target for cancer immunotherapy.

Immunosenescence, the aging of the immune system, leads to functional deficiencies, particularly in T cells, which undergo significant changes. While numerous studies have investigated age-related T-cell phenotypes in healthy aging, senescent T cells have also been observed in younger populations during pathological conditions like cancer. This review summarizes the recent advancements in age-associated alterations and markers of T cells, mechanisms, and the relationship between senescent T cells and the tumor microenvironment. We also discuss potential strategies for targeting senescent T cells to prevent age-related diseases and enhance tumor immunotherapy efficacy.

Defective autophagy of pericytes enhances radiation-induced senescence promoting radiation brain injury.

BACKGROUND: Radiation-induced brain injury (RBI) represents a major challenge for cancer patients undergoing cranial radiotherapy. However, the molecular mechanisms and therapeutic strategies of RBI remain inconclusive. With the continuous exploration of the mechanisms of RBI, an increasing number of studies have implicated cerebrovascular dysfunction as a key factor in RBI-related cognitive impairment. As pericytes are a component of the neurovascular unit, there is still a lack of understanding in current research about the specific role and function of pericytes in RBI. METHODS: We constructed a mouse model of RBI-associated cognitive dysfunction in vivo and an in vitro radiation-induced pericyte model to explore the effects of senescent pericytes on the blood-brain barrier and normal CNS cells, even glioma cells. To further clarify the effects of pericyte autophagy on senescence, molecular mechanisms were explored at the animal and cellular levels. Finally, we validated the clearance of pericyte senescence by using senolytic drug and all-trans retinoic acid to investigate the role of radiation-induced pericyte senescence. RESULTS: Our findings indicated that radiation-induced pericyte senescence plays a key role in blood-brain barrier dysfunction, leading to RBI and subsequent cognitive decline. Strikingly, pericyte senescence also contributes to the growth and invasion of glioma cells. We further demonstrate that defective autophagy in pericytes is a vital regulatory mechanism for pericyte senescence. Moreover, autophagy activated by rapamycin can reverse pericyte senescence. Notably, the elimination of senescent cells by senolytic drugs significantly mitigated radiation-induced cognitive dysfunction. DISSCUSSION: Our results demonstrated that pericyte senescence may be a promising therapeutic target for RBI and glioma progression.

Integrative Proteomics-Metabolomics of In Vitro Degeneration of Cardiovascular Cell Lines.

Long-term cell culture is an important biological approach but is also characterized by degeneration in cellular morphology, proliferation rate, and function. To explore this phenomenon in a systematic way, we conducted an integrative proteomics-metabolomics measurement of two cardiovascular cell lines of AC16 and HUVECs. The 18th culturing passages, i.e., G18, showed as the turning points by cell metabolism profiles, in which the metabolomic changes demonstrated the dysfunction of energy, amino acid, and ribonucleotide metabolism metabolic pathways. Although active protein networks showed mitochondria abundance AC16 and oxidative/nitrative sensitive HUVECs indicated the different degeneration patterns, the G18 and G30 proteomics evidenced the senescence by processes of signal transduction, signaling by interleukins, programmed cell death, cellular responses to stimuli, cell cycle, mRNA splicing, and translation. Some crucial proteins (RPS8, HNRNPR, SOD2, LMNB1, PSMA1, DECR1, GOT2, OGDH, PNP, CBS, ATIC, and IMPDH2) and metabolites (L-glutamic acid, guanine, citric acid, guanosine, guanosine diphosphate, glucose 6-phosphate, and adenosine) that contributed to the dysregulation of cellular homeostasis are identified by using the integrative proteomic-metabolomic analysis, which highlighted the increased cellular instability. These findings illuminate some vital molecular processes when culturing serial passages, which contribute holistic viewpoints of in vitro biology with emphasis on the replicative senescence of cardiovascular cells.

Artificial mitochondrial transplantation (AMT) reverses aging of mesenchymal stromal cells and improves their immunomodulatory properties in LPS-induced synoviocytes inflammation.

Nowadays, regenerative medicine techniques are usually based on the application of mesenchymal stromal cells (MSCs) for the repair or restoration of injured damaged tissues. However, the effectiveness of autologous therapy is limited as therapeutic potential of MSCs declines due to patient's age, health condition and prolonged in vitro cultivation as a result of decreased growth rate. For that reason, there is an urgent need to develop strategies enabling the in vitro rejuvenation of MSCs prior transplantation in order to enhance their in vivo therapeutic efficiency. In presented study, we attempted to mimic the naturally occurring mitochondrial transfer (MT) between neighbouring cells and verify whether artificial MT (AMT) could reverse MSCs aging and improve their biological properties. For that reason, mitochondria were isolated from healthy donor equine adipose-derived stromal cells (ASCs) and transferred into metabolically impaired recipient ASCs derived from equine metabolic syndrome (EMS) affected horses, which were subsequently subjected to various analytical methods in order to verify the cellular and molecular outcomes of the applied AMT. Mitochondria recipient cells were characterized by decreased apoptosis, senescence and endoplasmic reticulum stress while insulin sensitivity was enhanced. Furthermore, we observed increased mitochondrial fragmentation and associated PARKIN protein accumulation, which indicates on the elimination of dysfunctional organelles via mitophagy. AMT further promoted physioxia and regulated autophagy fluxes. Additionally, rejuvenated ASCs displayed an improved anti-inflammatory activity toward LPS-stimulated synoviocytes. The presented findings highlight AMT as a promising alternative and effective method for MSCs rejuvenation, for potential application in autologous therapies in which MSCs properties are being strongly deteriorated due to patients' condition.

Para-Hydroxycinnamic Acid Mitigates Senescence and Inflammaging in Human Skin Models.

Para-hydroxycinnamic acid (pHCA) is one of the most abundant naturally occurring hydroxycinnamic acids, a class of chemistries known for their antioxidant properties. In this study, we evaluated the impact of pHCA on different parameters of skin aging in in vitro skin models after H2O2 and UV exposure. These parameters include keratinocyte senescence and differentiation, inflammation, and energy metabolism, as well as the underlying molecular mechanisms. Here we demonstrate that pHCA prevents oxidative stress-induced premature senescence of human primary keratinocytes in both 2D and 3D skin models, while improving clonogenicity in 2D. As aging is linked to inflammation, referred to as inflammaging, we analyzed the release of IL-6, IL-8, and PGE2, known to be associated with senescence. All of them were downregulated by pHCA in both normal and oxidative stress conditions. Mechanistically, DNA damage induced by oxidative stress is prevented by pHCA, while pHCA also exerts a positive effect on the mitochondrial and glycolytic functions under stress. Altogether, these results highlight the protective effects of pHCA against inflammaging, and importantly, help to elucidate its potential mechanisms of action.