Promotes Cell Senescence Research Articles

Insights Into the Role of Bmi-1 Deregulation in Promoting Stemness and Therapy Resistance in Glioblastoma: A Narrative Review.

Glioblastoma (GBM) is the most common primary brain tumor in adults and has a median survival of less than 15 months. Advancements in the field of epigenetics have expanded our understanding of cancer biology and helped explain the molecular heterogeneity of these tumors. B-cell-specific Moloney murine leukemia virus insertion site-1 (Bmi-1) is a member of the highly conserved polycomb group (PcG) protein family that acts as a transcriptional repressor of multiple genes, including those that determine cell proliferation and differentiation. We hereby aim to explore the specific involvement of Bmi-1 in glioma pathogenesis. A comprehensive narrative review was employed using "PubMed". Articles were screened for relevance specific keywords and medical subject headings (MeSH) terms related to the topic combined with Boolean operators (AND, OR). Keywords and MeSH terms included the following: "glioma", "polycomb repressive complex 1", and "Bmi1". In GBMs, several reports have shown that Bmi-1 is overexpressed and might serve as a prognostic biomarker. We find that Bmi-1 participates in regulating the gene expression and chromatin structure of several tumor suppressor genes or cell cycle inhibitors. Bmi-1 has a critical role in modulating the tumor microenvironment to support the plasticity of GBM stem cells.We explore Bmi-1's involvement in maintaining glioma stem cell (GSC) proliferation and senescence evasion upon regulating the chromatin structure of several tumor suppressor genes, cell cycle inhibitors, or stem cell genes in tumor cells. Additionally, we analyze Bmi-1's involvement in modulating the DNA repair machinery or activating anti-apoptotic pathways to confer therapy resistance. Importantly, our research discusses the importance of targeting Bmi-1 that could be a promising therapeutic target for GBM treatment. Bmi-1 activates and interacts with NF-κB to promote angiogenesis and invasion, regulates the INK4a-ARF locus, and interacts with various microRNAs to influence tumor progression and proliferation. In addition, Bmi-1 confers radioresistance and chemotherapy by promoting cell senescence evasion and DNA repair. Bmi-1 regulates self-renewal, proliferation, and differentiation of GBM cells, promoting stemness and therapy resistance. Targeting Bmi-1 could be a promising novel therapeutic strategy for GBM treatment.

Network pharmacology and molecular docking reveal the mechanism of action of Bergapten against non‑small cell lung cancer.

Non-small cell lung cancer (NSCLC) is a leading cause of cancer mortality worldwide, necessitating new treatment approaches with minimal side effects. In the present study, the potential of Bergapten (5-methoxypsoralen), a natural furanocoumarin compound, as a therapeutic agent against NSCLC was investigated by using network pharmacology, molecular docking and in vitro validation. Bergapten targets were identified using the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform and SwissTarget databases, whilst lung cancer-related targets were sourced from GeneCards and DisGeNET. Protein-protein interaction analysis and molecular docking were performed to identify key targets. The inhibitory effects of Bergapten on lung cancer cells were assessed using Cell Counting Kit-8 assays, wound healing assays, cell migration experiments, flow cytometry and western blotting. SC79 was used to verify the regulation of Bergapten on the PI3K/AKT pathway. Network pharmacology identified 51 targets, one signaling pathway and four Gene Ontology projects associated with the action of Bergapten against NSCLC. Key targets identified included glycogen synthase kinase-3β, Janus kinase 2, phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit α and protein tyrosine kinase 2. In vitro experiments demonstrated that Bergapten significantly inhibited cell viability, promoted apoptosis, induced cellular senescence and inhibited the PI3K/AKT signaling pathway in NSCLC cells. In conclusion, Bergapten exerts its anti-NSCLC effects through the PI3K/AKT pathway, promoting cell senescence and inhibiting inflammation. These findings suggest that Bergapten has potential as a therapeutic agent for NSCLC.

Green flash extraction optimization of Cynanchum wilfordii adventitious roots and evaluation of their cancer cell inhibition

Adventitious root (AR) cultures of Cynanchum wilfordii are rich in bioactive compounds, including C21 steroidal glycosides. However, research on C. wilfordii ARs has focused on their culture, with limited attention on other aspects, affecting their further application. To provide a basis for the efficient utilization of this precious resource, in this study, flash extraction, a novel green extraction approach, was employed to extract C. wilfordii ARs, and the extraction process was optimized by applying response surface methodology (RSM) to maximize the yield of C21 steroidal glycosides. The obtained C. wilfordii AR extract (CWARE) was used to evaluate cancer cell inhibition by assessing cell viability, migration, senescence, and apoptosis. Through the optimization extraction process, flash extraction conditions of 69% ethanol concentration, 66 s of extraction time, and a 33 mL/g of liquid-to-material ratio were identified as optimal, resulting in a C21 steroidal glycoside yield of 9.22%. In evaluating cancer cell inhibition, we found that CWARE significantly (p < 0.01) inhibited the viability of all tested human cancer cell lines, with the human non-small-cell lung cancer cell line A549 exhibiting the highest sensitivity, showing a half-maximal inhibitory concentration of 195.4 μg/mL. Furthermore, CWARE inhibited A549 cell migration, promoted cell senescence, and induced apoptosis via both intrinsic and extrinsic pathways. These findings suggest that the optimized flash extraction process is efficient for extracting C. wilfordii ARs and the extract has a promising ability to inhibit cancer cells. This study provides a strong foundation for the further development and utilization of C. wilfordii ARs.

Alterations in the transcriptome and microRNAs of adipose-derived mesenchymal stem cells from different sites in rats during aging.

Aging is an intricate and gradual process characterized by tissue and cellular dysfunction. Adipose-derived mesenchymal stem cells (ADMSCs) experience a functional decline as part of systemic aging. However, the alterations in ADMSCs across various anatomical sites throughout an individual's lifespan remain unclear. To shed light on these changes, we collected white adipose tissue and brown adipose tissue samples from the epididymis, perirenal, inguinal, and scapular regions of young, adult, and aged rats and subsequently isolated ADMSCs for RNA sequencing. As aging progressed, we observed a reduction in the number of ADMSCs at all anatomical sites. Marker genes of ADMSCs from different sites were identified. Aging triggered notable activation of inflammatory and immune responses while diminishing the ADMSC differentiation capacity and ability to maintain a normal tissue morphology. Furthermore, miR-195-5p and miR-497-3p, which promoted cell senescence and apoptosis while inhibiting proliferation and differentiation, were positively correlated with aging. These findings increase our understanding of ADMSC senescence and underscore the unique physiological changes and functions of ADMSCs across different anatomical sites during aging.NEW & NOTEWORTHY Dynamic changes in mRNAs and miRNAs of ADMSCs during aging are shown. As aging progressed, we observed a reduction in the number of ADMSCs at all anatomical sites. Aging leads to the activation of inflammatory and cellular dysfunction. miR-195-5p and miR-497-3p are positively correlated with aging, which promoted cell senescence and apoptosis while inhibiting proliferation and differentiation. ADMSCs associated with different anatomical sites have site-specific markers.

ARID1A recruits GATA2 to regulate the senescence of trophoblast cells under high-glucose condition

IntroductionGestational diabetes mellitus (GDM) is a common complication during pregnancy. The hyperglycemic stimulation of gestational diabetes inhibits the invasion of the placental trophoblast cells. Some studies have indicated that the senescence of trophoblast cells weakens their invasive capacity, while the mechanism of trophoblast cells senescence in GDM remain elusive. MethodsWe performed western blotting and Immunohistochemical staining to investigate AT-Rich Interaction Domain 1A (ARID1A) expression in GDM placental tissues. 5 mM and 30 mM glucose treated HTR-8/SVneo cells to simulate normal glucose (NG) stress and high glucose (HG) stress. Cell proliferation capacity was investigated by CCK8 assay and cell cycle assay. SA-β-gal was used to detect cellular senescence. Chip-seq characterized the binding site of ARID1A to CDKN1A. In conjunction with bioinformatics analysis, co-immunoprecipitation assays, Chip-qPCR and luciferase reporter assays were performed to prove ARID1A recruits GATA2 to CDKN1A. ResultsWe found that ARID1A has a higher expression levels in GDM placental tissues compared to the control. ARID1A overexpression suppressed cell proliferation, induced cell cycle arrest and promoted cell senescence. Conversely the inhibition of ARID1A significantly rescues HG induced senescence of trophoblast cells. To further characterize the mechanism by which ARID1A regulate the transcription of CDKN1A, co-immunoprecipitation assays, Chip-qPCR and luciferase reporter assay indicate that ARID1A recruits GATA2 to regulate the transcriptional activity of CDKN1A. DiscussionOur study uncovers a ARID1A mediated regulatory mechanism in GDM trophoblast cell senescence and suggests that targeting the placental ARID1A might provide new diagnostic and therapeutic strategies for GDM.

T-2 Toxin Induces Immunosenescence in RAW264.7 Macrophages by Activating the HIF-1α/cGAS-STING Pathway.

T-2 toxin induces cell immunotoxicity by triggering an intracellular hypoxic microenvironment and activates hypoxia-inducible factor-1α (HIF-1α), which exerts cellular protective effects. Mycotoxins can also induce senescence. The aging of immune function, termed "immunosenescence," is an important factor in the decline of biological immunity and accelerates senescence. However, the mechanism underlying T-2 toxin-induced immunosenescence remains unclear. This study aimed to elucidate the roles of HIF-1α and cGAS-STING signaling in this process and uncover the mechanisms through which T-2 toxin impacts cytoskeletal integrity and cellular senescence using a RAW264.7 macrophage model. The cells were treated with T-2 toxin (14 nM) for 1-24 h. We revealed that T-2 toxin-induced immunosenescence in RAW264.7 cells by activating the HIF-1α/cGAS-STING axis. The cGAS-STING pathway promotes cell senescence and apoptosis; however, we revealed that HIF-1α negatively regulated this pathway, thereby inhibiting cellular senescence and apoptosis. However, PARP 1 cleavage by caspase 3/9 inhibited DNA repair and accelerated the transition from senescence to apoptosis. At the late stages of T-2 toxin exposure (12 h), HIF-1α accelerated cellular senescence by disrupting the dynamic balance of cytoskeletal α-tubulin and F-actin and destabilizing the cytoskeletal structure. Our research demonstrates that T-2 toxin induces immunosenescence in RAW264.7 cells by activating the cGAS-STING pathway, with HIF-1α signaling serving as a negative regulator. This study provides a deeper understanding of T-2 toxin-induced immunosenescence.

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

BackgroundPremature ovarian insufficiency (POI) is a condition characterized by a substantial decline or loss of ovarian function in women before the age of 40. However, the pathogenesis of POI remains to be further elucidated, and specific targeted drugs which could delay or reverse ovarian reserve decline are urgently needed. Abnormal DNA damage repair (DDR) and cell senescence in granulosa cells are pathogenic mechanisms of POI. Ubiquitin-specific protease 14 (USP14) is a key enzyme that regulates the deubiquitylation of DDR-related proteins, but whether USP14 participates in the pathogenesis of POI remains unclear.MethodsWe measured USP14 mRNA expression in granulosa cells from biochemical POI (bPOI) patients. In KGN cells, we used IU1 and siRNA-USP14 to specifically inhibit USP14 and constructed a cell line stably overexpressing USP14 to examine its effects on DDR function and cellular senescence in granulosa cells. Next, we explored the therapeutic potential of IU1 in POI mouse models induced by D-galactose.ResultsUSP14 expression in the granulosa cells of bPOI patients was significantly upregulated. In KGN cells, IU1 treatment and siUSP14 transfection decreased etoposide-induced DNA damage levels, promoted DDR function, and inhibited cell senescence. USP14 overexpression increased DNA damage, impaired DDR function, and promoted cell senescence. Moreover, IU1 treatment and siUSP14 transfection increased nonhomologous end joining (NHEJ), upregulated RNF168, Ku70, and DDB1, and increased ubiquitinated DDB1 levels in KGN cells. Conversely, USP14 overexpression had the opposite effects. Intraperitoneal IU1 injection alleviated etoposide-induced DNA damage in granulosa cells, ameliorated the D-galactose-induced POI phenotype, promoted DDR, and inhibited cell senescence in ovarian granulosa cells in vivo.ConclusionsUpregulated USP14 in ovarian granulosa cells may play a role in POI pathogenesis, and targeting USP14 may be a potential POI treatment strategy. Our study provides new insights into the pathogenesis of POI and a novel POI treatment strategy.

Culture dependent and independent approaches reveal the role of specific bacteria in human skin aging

AbstractSkin aging is a dynamic process involving a spectrum of phenotypic changes, making it an attractive model for studying microbiome‐phenotype interactions. Therefore, 822 facial microbial samples and 14 skin phenotypes from corresponding areas were assessed in a Chinese cohort. Porphyrins and the chronological age exhibited the most significant microbial variability. We further profiled the dynamics of the skin microbiome associated with age and aging phenotypes. Using a multiple linear regression model, we predicted premature/delayed aging‐related microbial species, mainly Moraxella osloensis and Cutibacterium acnes. We also validated the biological functions of the host‐microbe interactions in vitro. Moraxella osloensis isolated from healthy skin regulates collagen metabolism and extracellular matrix assembly, and promotes cell senescence in human keratinocytes and fibroblasts, making it potentially applicable in the development of antiaging interventions.

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

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

Effect and mechanism of curcumin on colon cancer cell senescence through early growth response 1 (EGR1).

The expression level of early growth response 1 (EGR1) is elevated in colon cancer (CC) tissues and is closely associated with poor prognosis in colorectal cancer. However, the role of EGR1 as a transcription factor (TF) influencing cell senescence in the progression of CC remains largely unexplored. This study aims to investigate the impact of curcumin on colorectal cancer cell senescence by modulating EGR1. Genes associated with cell senescence were obtained from a public database, and ChIP-X predicted TFs were utilized. The R2 database was employed to examine the relationship between gene expression and survival. CC cell lines were transfected with plasmids to achieve stable expression. Stable transfected cell lines were screened, and changes in RNA and protein expression were assessed using real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) and Western blot (WB) analysis. Senescence levels were measured by SA-β-Gal staining. Cell proliferation and invasion capabilities were evaluated through soft agar and Matrigel invasion assays. Molecular docking was used to predict the interaction between curcumin and EGR1. Gene activity changes were detected using a dual luciferase reporter gene assay. The results indicated that EGR1 was overexpressed in CC tissues and correlated with poor prognosis. As a TF, EGR1 negatively regulated the expression of telomerase reverse transcriptase (TERT) and sirtuin 6 (SIRT6) genes associated with cell senescence. Knocking down EGR1 increased the rate of cell senescence and inhibited cell proliferation and invasion. Curcumin inhibited the transcriptional activity of EGR1, thereby promoting cell senescence and inhibiting tumor progression. In conclusion, curcumin hampers the activity of TF EGR1, affecting the transcription and translation of target genes TERT and SIRT6, thus promoting cell senescence and inhibiting CC cell proliferation. These findings provide potential insights for targeted therapy of CC.

Association between metal exposures and periodontitis among U.S. adults: the potential mediating role of biological aging

BackgroundThis study aimed to investigate the associations between metal exposures and periodontitis among U.S. adults, as well as the mediated effect of biological aging.MethodsUsing data from the National Health and Nutrition Examination Survey (NHANES) 2009–2014, we explored the single and mixed impacts of metal exposures on periodontitis through adjusted weighted logistic regression, robust Poisson regression, restricted cubic spline regression, and Bayesian kernel machine regression models. This study included 2,393 participants, with 46.9% experiencing periodontitis. Concentrations of nine urinary metals, including barium (Ba), cadmium (Cd), cobalt (Co), cesium (Cs), molybdenum (Mo), lead (Pb), thallium (Tl), tungsten (Tu), and uranium (Ur), were measured using inductively coupled plasma-mass spectrometry. In addition, we analyzed the association between metals and periodontitis, stratified by age, body mass index, gender, and smoking status. Mediation models were also applied to investigate the mediated effects of biological aging between metal exposures and periodontitis.ResultsWeighted logistic and robust Poisson regression identified positive associations between Cd, Pb and periodontitis (P < 0.05). BKMR analyses indicated that mixed metal exposures were significantly associated with periodontitis, particularly among smokers, second-hand smokers, and males, with Cd, Pb, Tl, and Ba contributing the most. Furthermore, subgroup analyses observed a modifying effect on the associations between urinary Cd, Pb and periodontitis in stratified gender and BMI subgroups in robust Poisson regression. Phenotype age was found to mediate the association between metals and periodontitis.ConclusionsThis study identified significant positive associations between metal exposures and periodontitis in the U.S. adults. In addition, the association between metal exposures and periodontitis could vary in different gender, BMI and smoking subgroups. These associations were likely partly mediated by biological aging, suggesting that metals may potentially increase the risk of periodontitis by promoting cell senescence and overall aging of the body.Graphical

Identification of vilazodone as a novel plasminogen activator inhibitor to overcome Alzheimer's disease through virtual screening, molecular dynamics simulation, and biological evaluation.

Urokinase-type plasminogen activator (PLAU), a member of the S1 serine peptidase family in Clan PA, plays a crucial role in the conversion of plasminogen into active plasmin. However, the precise role of PLAU in the central nervous system remains incompletely elucidated, particularly, in relation to Alzheimer's disease (AD). In this study, we successfully identified that PLAU could promote cell senescence in neurons, indicating it as a potential target for ADtreatment through a systematic approach, which included both bioinformatics analysis and experimental verification. Subsequently, a structure-based virtual screening approach was employed to identify a potential PLAU inhibitor from theFood and Drug Administration-approved drug database. After analyzing docking scores and thoroughly examining the receptor-ligand complex interaction modes, vilazodone emerges as a highly promising PLAU inhibitor. Additionally, molecular docking and molecular dynamics simulations were performed to generate a complex structure between the relatively stable inhibitor vilazodone and PLAU. Of note, vilazodone exhibited superior cytotoxicity against senescent cells, showing a senolytic activity through targeting PLAU and ultimately producing an anti-AD effect. These findings suggest that targeting PLAU could represent a promising therapeutic strategy for AD. Furthermore, investigating the inhibitory potential and structural modifications based on vilazodone may provide valuable insights for future drug development targeting PLAU in AD disorders.

YAP upregulates AMPKα1 to induce cancer cell senescence

Yes-associated protein (YAP)—a major effector protein of the Hippo pathway— regulates cell proliferation, differentiation, apoptosis, and senescence. Amp-activated protein kinase (AMPK) is a key sensor that monitors cellular nutrient supply and energy status. Although YAP and AMPK are considered to regulate cellular senescence, it is still unclear whether AMPK is involved in YAP-regulated cellular senescence. Here, we found that YAP promoted AMPKα1 aggregation and localization around mitochondria by co-transfecting CFP-YAP and YFP-AMPKα1 plasmids. Subsequent live cell fluorescence resonance energy transfer (FRET) assay did not exhibit direct interaction between YAP and AMPKα1. FRET, Co-immunoprecipitation, and western blot experiments revealed that YAP directly bound to TEAD, enhancing the expression of AMPKα1 and p-AMPKα. Treatment with verteporfin inhibited YAP’s binding to TEAD and reversed the elevated expression of AMPKα1 in the cells overexpressing CFP-YAP. Verteporfin also reduced the proportion of AMPKα1 puncta in the cells co-expressing CFP-YAP and YFP-AMPKα1. In addition, the AMPKα1 puncta were demonstrated to inhibit cell viability, autophagy, and proliferation, and ultimately promote cell senescence. In conclusion, YAP binds to TEAD to upregulate AMPKα1 and promotes the formation of AMPKα1 puncta around mitochondria under the condition of co-expression of CFP-YAP and YFP-AMPKα1, in which AMPKα1 puncta lead to cellular senescence.

Platycodin D2 enhances P21/CyclinA2-mediated senescence of HCC cells by regulating NIX-induced mitophagy

BackgroundHepatocellular carcinoma (HCC) cells usually show strong resistance to chemotherapy, which not only reduces the efficacy of chemotherapy but also increases the side effects. Regulation of autophagy plays an important role in tumor treatment. Cell senescence is also an important anti-cancer mechanism, which has become an important target for tumor treatment. Therefore, it is of great clinical significance to find anti-HCC drugs that act through this new mechanism. Platycodin D2 (PD2) is a new saponin compound extracted from the traditional Chinese medicine Platycodon grandiflorum.PurposeOur study aimed to explore the effects of PD2 on HCC and identify the underlying mechanisms.MethodsFirst, the CCK8 assay was used to detect the inhibitory effect of PD2 on HCC cells. Then, different pathways of programmed cell death and cell cycle regulators were measured. In addition, we assessed the effects of PD2 on the autophagy and senescence of HCC cells by flow cytometry, immunofluorescence staining, and Western blotting. Finally, we studied the in vivo effect of PD2 on HCC cells by using a mouse tumor-bearing model.ResultsStudies have shown that PD2 has a good anti-tumor effect, but the specific molecular mechanism has not been clarified. In this study, we found that PD2 has no obvious toxic effect on normal hepatocytes, but it can significantly inhibit the proliferation of HCC cells, induce mitochondrial dysfunction, enhance autophagy and cell senescence, upregulate NIX and P21, and downregulate CyclinA2. Gene silencing and overexpression indicated that PD2 induced mitophagy in HCC cells through NIX, thereby activating the P21/CyclinA2 pathway and promoting cell senescence.ConclusionsThese results indicate that PD2 induces HCC cell death through autophagy and aging. Our findings provide a new strategy for treating HCC.Graphical

AS1041, a novel derivative of marine natural compound Aspergiolide A, induces senescence of leukemia cells via oxidative stress-induced DNA damage and BCR-ABL degradation

Chronic myelogenous leukemia (CML) is characterized by the constitutive activation of BCR-ABL tyrosine kinase. Imatinib was approved for CML therapy, however, BCR-ABL-dependent drug resistance, especially BCR-ABL-T315I mutation, restricts its clinical application. In this study, we reported anthraquinone lactone AS1041, a synthesized derivative of marine natural compound Aspergiolide A, showed anti-leukemia effect in vitro and in vivo by promoting cell senescence. Mechanistic study revealed the pro-senescence effect of AS1041 was dependent on oxidative stress-induced DNA damage, and the resultant activation of P53/P21 and P16INK4a/Rb. Also, AS1041 promoted ubiquitin proteasome system (UPS)-mediated BCR-ABL degradation, which also contributed to AS1041-induced senescence. In vivo, AS1041-induced senescence promoted tumor growth inhibition. In summary, the in vitro and in vivo antitumor effect of AS1041 suggests it can serve as a pro-senescence agent for alternative antileukemia therapy and imatinib-resistant cancer therapy by enhancing cellular oxidative stress and BCR-ABL degradation.

Phytic acid improves osteogenesis and inhibits the senescence of human bone marrow mesenchymal stem cells under high-glucose conditions via the ERK pathway

Hyperglycaemia causes impairment of osteogenic differentiation and accelerates stem cell senescence, resulting in weakened osteogenesis and disordered bone metabolism. Phytic acid (PA) is an antioxidant that is reportedly beneficial to bone homeostasis. The present study aims to clarify how PA affects the osteogenic capacity and cellular senescence of bone marrow mesenchymal stem cells (BMSCs) exposed to high-glucose environments, as well as the potential molecular mechanisms. Our results indicate that osteogenic differentiation in BMSCs cultivated in high-glucose conditions is enhanced by PA, as evidenced by increased alkaline phosphatase activity and staining, Alizarin Red S staining, osteogenic marker in in vitro studies, and increased osteogenesis in animal experiments. PA also prevented high-glucose-induced senescence of BMSCs, as evidenced by the repression of reactive oxygen species production, senescence-associated β-galactosidase staining, and P21 and P53 expression. Furthermore, it was found that PA rescued the high-glucose-inhibited expression of phosphorylated extracellular regulated protein kinases (p-ERK). The inhibition of ERK pathway by the specific inhibitor PD98059 blocked the PA-enhanced osteogenesis of BMSCs and promoted cell senescence. Our results revealed that PA enhances osteogenic differentiation and inhibits BMSC senescence in a high-glucose environment. In addition, the activation of the ERK pathway seems to mediate the beneficial effects of PA. The findings provide novel insights that could facilitate bone regeneration in patients with diabetes.

HPF1 regulates tendon stem/progenitor cell senescence and tendon repair via PARP1-mediated poly-ADP ribosylation of HuR.

Tendon stem/progenitor cells (TSPCs) play a vital role in tendon repair, regeneration and homeostasis. However, the specific mechanism of TSPCs aging is still unclear. This study aims to explore the role and molecular mechanism of HPF1 in the aging of TSPCs. Young and aged TSPCs (Y-TSPCs and A-TSPCs) were acquired from 3 to 4 and 24-26-month-old Sprague-Dawley male rats, TSPCs (Y-TSPCs and A-TSPCs) were subjected to senescence-associated β-galactosidase (SA-β-Gal))staining and telomerase activity detection, p16, p21, Scx, Tnmd, Col1, Col3HPF1 and PAPR1 expression levels were detected by Western blot or Reverse Transcription-quantitative Polymerase Chain Reaction (RT-qPCR), Reciprocal co-immunoprecipitation (co-IP) was used to explore the interaction between HPF1 and PARP1. Ribonucleoprotein immunoprecipitation (RNP-IP) was used to analyze the binding of HuR to the senescence marker gene mRNAs, IP was used to perform HPF1 to the PARylation of HuR, and the half-life of p16 and p21 were detected. Finally, we established an in vivo model, and the tendon tissue was used to perform hematoxylin and eosin (HE) and masson's trichrome staining, as well as the immunohistochemical analysis of Col I and TNMD. Compared with Y-TSPCs, A-TSPCs had significantly enhanced cell senescence and significantly reduced tendon differentiation ability, and significantly increased the expression of HPF1 and PARP1. In addition, HPF1 and PARP1 interacted and coordinated the senescence and differentiation of TSPCs, HPF1 could also regulate the expression of p21 and p21, the interaction of p16 or p21 with HuR, and the poly-ADP ribosylation of PARP1 to HuR. HPF1 overexpression and siHuR co-transfection significantly reduced the half-life of p16 and p21, and HPF1 and PARP1 regulated the mRNA levels of p16 and p21 through HuR. Finally, in vivo experiments have shown that HPF1 or PARP1 overexpression could both inhibit the ability of tendon differentiation and promote cell senescence. HPF1 promoted the senescence of TSPCs and inhibits the tendon differentiation of TSPCs through PARP1-mediated poly-ADP ribosylation of HuR.

USP13 regulates cell senescence through mediating MDM2 stability

AimsLung aging results in altered lung function, reduced lung remodeling and regenerative capacity, and increased susceptibility to acute and chronic lung diseases. The molecular and physiological underlying mechanisms of lung aging remain unclear. Mounting evidence suggests that deubiquitinating enzymes (DUBs) play a critical role in tissue aging and diseases through regulation of cellular signaling pathways. Here we investigate the role of Ubiquitin-Specific Protease 13 (USP13) in cell senescence and lung aging and its underlying mechanisms. Main methodsProtein levels of USP13 and MDM2 in lung tissues from aged and young mice were compared. Gene silencing and overexpression of USP13 in human cell lines were performed. MDM2 levels were examined by Quantitative Real-Time PCR and Western blotting analysis. The cell senescence levels of human cells were checked by the β-galactosidase staining. Key findingsLung tissues from aged mice showed higher levels of USP13 compared to younger mice. We found a negative correlation between USP13 and MDM2 expression in lung tissues of aged mice. The increased protein levels of MDM2 were detected in lung tissues of USP13 deficient mice. Furthermore, overexpression of USP13 promoted cell senescence. Knockdown of USP13 increased MDM2 levels in lung cells, while overexpression of USP13 reduced it. The degradation of MDM2 caused by USP13 was prevented by the proteasome inhibitor MG132. Furthermore, we showed that USP13 targeted and reduced K63-linked polyubiquitination of MDM2. These results demonstrate that USP13 is involved in the aging signaling pathway in lungs through regulation of MDM2.

Promotion of NAD+ recycling by the hypoxia-induced shift in the lactate dehydrogenase isozyme profile reduces the senescence of human bone marrow-derived endothelial progenitor cells

Expansion of bone marrow-derived endothelial progenitor cells (EPCs) in vitro to obtain required cell numbers for therapeutic applications faces the challenge of growing cell senescence under the traditional normoxic culture condition. We previously found that 1% O2 hypoxic culture condition is favorable for reducing senescence of EPCs, but the mechanisms underlying the favorability are still unclear. Here, we found that, compared with normoxia, hypoxia induced a shift in lactate dehydrogenase (LDH) isozyme profile, which manifested as decreased LDH2 and LDH1 and increased LDH5, LDH4 and total LDHs. Moreover, under hypoxia, EPCs presented higher LDH activity, which could promote the conversion of pyruvate to lactate, as well as a higher level of NAD+, Bcl2 interacting protein 3 (BNIP3) expression and mitophagy. Additionally, under hypoxia, knock-down of the LDHA subunit increased the LDH2 and LDH1 levels and knock-down of the LDHB subunit increased the LDH5 level, while the simultaneous knock-down of LDHA and LDHB reduced total LDHs and NAD+ level. Inhibition of NAD+ recycling reduced BNIP3 expression and mitophagy and promoted cell senescence. Taken together, these data demonstrated that 1% O2 hypoxia induces a shift in the LDH isozyme profile, promotes NAD+ recycling, increases BNIP3 expression and mitophagy, and reduces EPC senescence. Our findings contribute to a better understanding of the connection between hypoxic culture conditions and the senescence of bone marrow-derived EPCs and provide a novel strategy to improve in vitro expansion of EPCs.

Hydroxysafflor yellow A protects against thioacetamide-induced liver fibrosis in rats via suppressing proinflammatory/fibrogenic mediators and promoting hepatic stellate cell senescence and apoptosis

Objective: To evaluate the effect of hydroxysafflor yellow A (HSYA) on thioacetamide-induced liver fibrosis. Methods: Thioacetamide was administered to rats intraperitoneally in doses of 200 mg/kg twice a week for 12 weeks. Thioacetamide-intoxicated rats were given silymarin (50 mg/kg) or HSYA (5 mg/kg) orally every day for 8 weeks. Liver enzymes, fibrosis markers, histological changes as well as immunohistochemistry of TNF-α, IL-6, p21, α-SMA, and caspase-3 were examined. The effect of HSYA on HSC-T6 activation/proliferation and apoptosis was also determined in vitro. Results: HSYA decreased liver enzymes, TNF-α, IL-6, and p21 expressions, hepatic PDGF-B, TIMP-1, TGF-β1, and hydroxyproline levels, as well as fibrosis score (S2 vs. S4) compared to the thioacetamide group. HSYA also downregulated α-SMA while increasing caspase-3 expression. Surprisingly, at 500 μg/mL, HSYA had only a slightly suppressive effect on HSC proliferation, with a 9.5% reduction. However, it significantly reduced TGF-β1, inhibited α-SMA expression, induced caspase-3 expression, and promoted cell senescence. Conclusions: HSYA may be a potential therapeutic agent for delaying and reversing the progression of liver fibrosis. More research on HSYA at higher doses and for a longer period is warranted.