Oxidative Stress-induced Senescence Research Articles

Reduced sulfatide content in deferoxamine-induced senescent HepG2 cells.

Iron chelators, such as deferoxamine, exert an anticancer effect by altering the activity of biomolecules critical for regulation of the cell cycle, cell metabolism, and apoptotic processes. Thus, iron chelators are sometimes used in combination with radio- and/or chemotherapy in the treatment of cancer. The possibility that deferoxamine could induce a program of senescence similar to radio- and/or chemotherapy, fostering adaptation in the treatment of cancer cells, is not fully understood. Using established biochemical techniques, biomarkers linked to lipid composition, and coherent anti-Stokes Raman scattering microscopy, we demonstrated that hepatocellular carcinoma-derived HepG2 cells survive after deferoxamine treatment, acquiring phenotypic traits and representative hallmarks of senescent cells. The results support the view that deferoxamine acts in HepG2 cells to produce oxidative stress-induced senescence by triggering sequential mitochondrial and lysosomal dysfunction accompanied by autophagy blockade. We also focused on the lipidome of senescent cells after deferoxamine treatment. Using mass spectrometry, we found that the deferoxamine-induced senescent cells presented marked remodeling of the phosphoinositol, sulfatide, and cardiolipin profiles, which all play a central role in cell signaling cascades, intracellular membrane trafficking, and mitochondria functions. Detection of alterations in glycosphingolipid sulfate species suggested modifications in ceramide generation, and turnover is frequently described in cancer cell survival and resistance to chemotherapy. Blockade of ceramide generation may explain autophagic default, resistance to apoptosis, and the onset of senescence. DATA AVAILABILITY STATEMENT: All analyses relevant to the study were included in the article or uploaded as Supplementary Information.

Aerobic Exercise-Mimetic Effects of Resveratrol on the Prevention of Vascular Endothelial Senescence

PURPOSE: Regular exercise has been shown to have anti-aging effects on the vascular system by improving endothelial function and diminishing oxidative stress. However, adherence to an exercise regimen can be difficult for some individuals, particularly those with limited mobility. This study investigated the effects of resveratrol as an exercise mimetic for preventing and improving oxidative stressinduced senescence in vascular endothelial cells.METHODS: Cultured human umbilical vein endothelial cells were used to investigate the reversal effects of laminar shear stress and the protective effects of resveratrol on oxidative stress-induced premature senescence. Senescence was estimated using SA-β-gal staining and western blot analysis, whereas oxidative stress levels were evaluated using MitoSOX staining. Matrigel tube formation and scratch assays were also performed to assess endothelial angiogenic and migration functions.RESULTS: The study showed that laminar shear stress could partly normalize premature endothelial senescence. Resveratrol pretreatment attenuated reactive oxygen species production and prevented senescence in H2O2-induced premature aging. Additionally, resveratrol contributed to maintaining endothelial cells’ angiogenic and migratory functions.CONCLUSIONS: This study demonstrated that laminar shear stress can mitigate the effects of oxidative stress-induced premature senescence. Resveratrol may be a potential substitute for exercise to prevent age-related damage to the endothelium by increasing resistance to oxidative stress and improving endothelial function.

Angelica sinensis polysaccharides alleviate the oxidative burden on hematopoietic cells by restoring 5-fluorouracil-induced oxidative damage in perivascular mesenchymal progenitor cells

Context 5-Fluorouracil (5-FU)-injured stromal cells may cause chronic bone marrow suppression; however, the underlying mechanism remains unclear. Angelica sinensis polysaccharide (ASP), the main biologically active ingredient of the Chinese herb, Angelica sinensis (Oliv.) Diels (Apiaceae), may enrich the blood and promote antioxidation. Objective This study investigated the protective antioxidative effects of ASP on perivascular mesenchymal progenitors (PMPs) and their interactions with hematopoietic cells. Materials and methods PMPs were dissociated from C57BL/6 mouse femur and tibia and were subsequently divided into the control, ASP (0.1 g/L), 5-FU (0.025 g/L), and 5-FU + ASP (pre-treatment with 0.1 g/L ASP for 6 h, together with 0.025 g/L 5-FU) then cultured for 48 h. Hematopoietic cells were co-cultured on these feeder layers for 24 h. Cell proliferation, senescence, apoptosis, and oxidative indices were detected, along with stromal osteogenic and adipogenic differentiation potentials. Intercellular and intracellular signaling was analyzed by real-time quantitative reverse transcription polymerase chain reaction and Western blotting. Results ASP ameliorated the reactive oxygen species production/scavenge balance in PMPs; improved osteogenic differentiation; increased SCF, CXCL12, VLA-4/VCAM-1, ICAM-1/LFA1, and TPO/MPL, Ang-1/Tie-2 gene expression. Further, the ASP-treated feeder layer alleviated hematopoietic cells senescence (from 21.9 ± 1.47 to 12.1 ± 1.13); decreased P53, P21, p-GSK-3β, β-catenin and cyclin-D1 protein expression, and increased glycogen synthase kinase (GSK)-3β protein expression in co-cultured hematopoietic cells. Discussion and conclusions ASP delayed oxidative stress-induced premature senescence of 5-FU-treated feeder co-cultured hematopoietic cells via down-regulation of overactivated Wnt/β-catenin signaling. These findings provide a new strategy for alleviating myelosuppressive stress.

The lncRNA OIP5-AS1/miR-4500 axis targeting ARG2 modulates oxidative stress-induced premature senescence in endothelial cells: implications for vascular aging

ABSTRACT Background Endothelial senescence due to increased age or oxidative stress can cause endothelial dysfunction, which is strongly associated with the pathogenesis of cardiovascular diseases (CVDs). Research design and methods Hydrogen peroxide (H2O2) was used to induced human umbilical vein endothelial cells (HUVECs) senescence model. Cell senescence and cell proliferation were assessed by SA-β-gal staining and PCNA staining. Nitric oxide (NO) and reactive oxygen species (ROS) levels were detected by DAF-2 DA and DCFH-DA. Inflammatory indicators were quantified by qPCR. Meanwhile, western blot was used to examine the ARG2 protein. Finally, an aging mice model induced by H2O2 was established to confirm the role of OIP5-AS1/miR-4500/ARG2 in endothelial dysfunction in vivo. Results ARG2 was upregulated and miR-4500 was reduced in H2O2-induced HUVECs. MiR-4500 negatively regulates ARG2 expression, meanwhile ameliorating H2O2-induced ECs senescence and dysfunction. Targeted interactions among OIP5-AS1, miR-4500, and ARG2 were confirmed by dual-luciferase reporter assays. OIP5-AS1 as miR4500 sponge negatively mediates miR-4500 expression, and is upregulated upon H2O2 stimulation in HUVECs. OIP5-AS1 depletion shows the protective effects on H2O2-induced ECs senescence, dysfunction, and SASP. In vivo, a higher expression of OIP5-AS1 and ARG2 in the aortas of aged mice. Conclusions We disclosed a regulatory mechanism for OIP5-AS1/miR-4500/ARG2 in the regulation of oxidative stress-related ECs senescence and vascular aging.

S-sulfhydration of SIRT3 combats BMSC senescence and ameliorates osteoporosis via stabilizing heterochromatic and mitochondrial homeostasis

Senescence of bone marrow mesenchymal stem cells (BMSCs) is one of the leading causes of osteoporosis. SIRT3, an essential NAD-dependent histone deacetylase, is highly correlated with BMSC senescence-mediated bone degradation and mitochondrial/heterochromatic disturbance. S-sulfhydration of cysteine residues favorably enhances SIRT3 activity by forming persulfides. Nevertheless, the underlying molecular mechanism of SIRT3 S-sulfhydration on mitochondrial/heterochromatic homeostasis involved in BMSC senescence remains unknown. Here, we demonstrated that CBS and CSE, endogenous hydrogen sulfide synthases, are downregulated with BMSC senescence. Exogenous H2S donor NaHS-mediated SIRT3 augmentation rescued the senescent phenotypes of BMSCs. Conversely, SIRT3 deletion accelerated oxidative stress-induced BMSC senescence through mitochondrial dysfunction and the detachment of the heterochromatic protein H3K9me3 from the nuclear envelope protein Lamin B1. H2S-mediated SIRT3 S-sulfhydration modification rescued the disorganized heterochromatin and fragmented mitochondria induced by the S-sulfhydration inhibitor dithiothreitol, thus leading to elevated osteogenic capacity and preventing BMSC senescence. The antisenescence effect of S-sulfhydration modification on BMSCs was abolished when the CXXC sites of the SIRT3 zinc finger motif were mutated. In vivo, aged mice-derived BMSCs pretreated with NaHS were orthotopically transplanted to the ovariectomy-induced osteoporotic mice, and we proved that SIRT3 ameliorates bone loss by inhibiting BMSC senescence. Overall, our study for the first time indicates a novel role of SIRT3 S-sulfhydration in stabilizing heterochromatin and mitochondrial homeostasis in counteracting BMSC senescence, providing a potential target for the treatment of degenerative bone diseases.

PCK2 inhibits lung adenocarcinoma tumor cell immune escape through oxidative stress-induced senescence as a potential therapeutic target.

Our research aimed to better understand how phosphoenolpyruvate carboxykinase 2 (PCK2) is linked to survival outcomes in lung cancer patients. We confirmed PCK2 expression and its association with the outcome of lung cancer patients using The Cancer Genome Atlas (TCGA) database. PCK2 and immune cell connections were investigated using data from the Tumor IMmune Estimation Resource (TIMER) and TCGA repositories. We used the CancerSEA database to examine the links between PCK2 expression and the efficiency of lung adenocarcinomas, and a T-distributed Stochastic Neighbor Embedding (T-SNE) map was constructed to show the expression profile of PCK2 in single cells in TCGA lung adenocarcinoma samples. The potential mechanism of action was finally investigated using Gene Set Enrichment Analysis (GSEA) enrichment analysis, Gene Ontology (GO) pathway enrichment analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. The expression of PCK was lower in lung adenocarcinoma tumor tissues than in paracancerous tissues. Patients with lung adenocarcinoma who expressed PCK2 at high levels fared better in overall survival (OS), disease-specific survival (DSS), and progression free interval (PFI). PCK2 was positively correlated with programmed cell death 1 (PDCD1) expression, and its mutation rate in lung adenocarcinoma was 0.53%. CancerSEA research revealed that in lung adenocarcinoma, PCK2 was negatively correlated with epithelial-mesenchymal transition (EMT) and hypoxia. Gene ontology and KEGG enrichment analysis revealed PCK2-coexpressed genes influenced the onset and progression of lung adenocarcinoma by modulating the activity of DNA-binding transcriptional activators, the specificity of RNA polymerase II, the interaction between neuroactive ligands and their receptors, and the cAMP signaling pathway. The prognosis for lung adenocarcinoma was shown to vary according to whether PCK2 was involved in the response to oxidative stress-induced senescence, gene silencing, cell cycle, and other biological processes. An increased expression of PCK2 may be employed as a novel prognostic biomarker in patients with lung adenocarcinoma and has been shown to increase OS, DSS, and PFI. Improving the prognosis of lung adenocarcinoma by interference with PCK2 may be possible since it induces senescence through the oxidative stress response and blocks the immune escape of tumor cells. These results point to a probable target anticancer treatment development in lung adenocarcinoma.

Interleukin-23 mediates the reduction of GADD45a expression to attenuate oxidative stress-induced cellular senescence in human fibroblasts

The interleukin-23 (IL-23) plays a key role in various inflammatory diseases, such as spondyloarthritis, by acting on target cells through the IL-23/IL-17 pathway. Recent studies have suggested that IL-23 can also directly affect fibroblasts. Senescent fibroblasts are implicated in many physiological and pathological processes, including those related to inflammatory diseases. However, it remains unclear whether IL-23 can influence fibroblast senescence and contribute to pathogenesis. In our study, we investigated the effects of IL-23 on oxidative stress-induced senescence in human fibroblasts, using the H2O2-induced senescence model, and found that IL-23 pre-treatment significantly attenuated senescence in these cells. RNA-seq and in vitro experiments indicate that IL-23 may act by regulating GADD45a expression and the p38/MAPK pathway. Furthermore, we confirmed that IL-23 inhibits oxidative stress-induced up-regulation of GADD45a expression and subsequent activation of the p38/MAPK pathway through GADD45a knockdown and overexpression experiments. Our study is the first to demonstrate that IL-23 can effectively suppress the senescence of fibroblasts induced by oxidative stress, by inhibiting the H2O2-triggered induction of GADD45a and subsequent activation of the p38/MAPK pathway. These findings have significant implications for understanding the role of IL-23 in immune-inflammatory diseases and may provide a new avenue for the diagnosis and treatment of these conditions.

Molecular Mobility of Polyrotaxane Surfaces Alleviates Oxidative Stress-Induced Senescence in Mesenchymal Stem Cells.

Polyrotaxane is a supramolecular assembly consisting of multiple cyclic molecules threaded by a linear polymer. One of the unique properties of polyrotaxane is molecular mobility, cyclic molecules moving along the linear polymer. Molecular mobility of polyrotaxane surfaces affects cell spreading, differentiation, and other cell-related aspects through changing subcellular localization of yes-associated proteins (YAPs). Subcellular YAP localization is also related to cell senescence derived from oxidative stress, which is known to cause cancer, diabetes, and heart disease. Herein, the effects of polyrotaxane surface molecular mobility on subcellular YAP localization and cell senescence following H2 O2 -induced oxidative stress are evaluated in human mesenchymal stem cells (HMSCs) cultured on polyrotaxane surfaces with different molecular mobilities. Oxidative stress promotes cytoplasmic YAP localization in HMSCs on high-mobility polyrotaxane surfaces; however, low-mobility polyrotaxane surfaces more effectively maintain nuclear YAP localization, exhibiting lower senescence-associated β-galactosidase activity and senescence-related gene expression and DNA damage than that seen with the high-mobility surfaces. These results suggest that the molecular mobility of polyrotaxane surfaces regulates subcellular YAP localization, thereby protecting HMSCs from oxidative stress-induced cell senescence. Applying the molecular mobility of polyrotaxane surfaces to implantable scaffolds can provide insights into the prevention and treatment of diseases caused by oxidative stress.

Rejuvenation of tendon stem/progenitor cells for functional tendon regeneration through platelet-derived exosomes loaded with recombinant Yap1.

The regenerative capabilities including self-renewal, migration and differentiation potentials shift from the embryonic phase to the mature period of endogenous tendon stem/progenitor cells (TSPCs) characterize restricted functions and disabilities following tendon injuries. Recent studies have shown that tendon regeneration and repair rely on multiple specific transcription factors to maintain TSPCs characteristics and functions. Here, we demonstrate Yap, a Hippo pathway downstream effector, is associated with TSPCs phenotype and regenerative potentials through gene expression analysis of tendon development and repair process. Exosomes have been proven an efficient transport platform for drug delivery. In this study, purified exosomes derived from donor platelets are loaded with recombinant Yap1 protein (PLT-Exo-Yap1) via electroporation to promote the stemness and differentiation potentials of TSPCs in vitro. Programmed TSPCs with Yap1 import maintain stemness and functions after long-term passage in vitro. The increased oxidative stress levels of TSPCs are related to the phenotype changes in duplicative senescent processes. The results show that treatment with PLT-Exo-Yap1 significantly protects TSPCs against oxidative stressor-induced stemness loss and senescence-associated secretory phenotype (SASP) through the NF-κB signaling pathway. In addition, we fabricate an Exos-Yap1-functioned GelMA hydrogel with a parallel-aligned substrate structure to enhance TSPCs adhesion, promote cell stemness and force regenerative cells toward the tendon lineage for in vitro and in vivo tendon regeneration. The application of Exos-Yap1 functioned implant assists new tendon-like tissue formation with good mechanical properties and locomotor functions in a full-cut Achilles tendon defect model. Thus, PLT-Exo-Yap1-functionalized GelMA promotes the rejuvenation of TSPCs to facilitate functional tendon regeneration. STATEMENT OF SIGNIFICANCE: This is the first study to explore that the hippo pathway downstream effector Yap is involved in tendon aging and repair processes, and is associated with the regenerative capabilities of TSPCs. In this syudy, Platelet-derived exosomes (PLT-Exos) act as an appropriate carrier platform for the delivery of recombinant Yap1 into TSPCs to regulate Yap activity. Effective Yap1 delivery inhibit oxidative stress-induced senescence associated phenotype of TSPCs by blocking ROS-mediated NF-κb signaling pathway activation. This study emphasizes that combined application of biomimetic scaffolds and Yap1 loaded PLT-Exos can provide structural support and promote rejuvenation of resident cells to assist functional regeneration for Achilles tendon defect, and has the prospect of clinical setting.

Tetrahydroxystilbene Glucoside Attenuates Oxidative Stress-Induced Aging by Regulating Oxidation Resistance and Inflammation in Larval Zebrafish.

Population aging is a global problem worldwide, and the discovery of antiaging drugs and knowledge of their potential molecular mechanisms are research hotspots in biomedical field. Tetrahydroxystilbene glucoside (TSG) is a natural component isolated from Heshouwu (Polygonum multiflorum Thunb.). It has been widely used to treat various chronic diseases for its remarkable biological activities. In this study, we successfully established aging larval zebrafish by exposing larvae to 2 mM hydrogen peroxide (H2O2). Using this aging model, we assessed the antiaging effect of TSG with different concentrations (25-100 μg/mL). After being treated with H2O2, zebrafish showed the obvious aging-associated phenotypes characterized by higher senescence-associated β-galactosidase activity, significantly downregulated expression of sirtuin 1 (sirt1) and telomerase reverse transcriptase (tert), and upregulated serpine1 mRNA level compared to the control group. TSG pretreatment delayed the aging process of oxidative stress-induced zebrafish, indicative of the reduced positive rate of senescence-associated β-galactosidase, improved swimming velocity, and stimulus-response capacity. Further studies proved that TSG could suppress reactive oxygen species production and enhance the activity of antioxidant enzymes superoxide dismutase and catalase. TSG also inhibited the H2O2-induced expressions of inflammation-related genes il-1β, il-6, cxcl-c1c, and il-8 in aging zebrafish, but it did not affect apoptosis-related genes (bcl-2, bax, and caspase-3) of aging zebrafish. In conclusion, TSG can protect against aging by regulating the antioxidative genes and enzyme activity, as well as inflammation in larval zebrafish, providing insight into the application of TSG for clinical treatment of aging or aging-related diseases.

The Extracellular Matrix Vitalizer RATM Increased Skin Elasticity by Modulating Mitochondrial Function in Aged Animal Skin

Oxidative stress-induced cellular senescence and mitochondrial dysfunction result in skin aging by increasing ECM levels-degrading proteins such as MMPs, and decreasing collagen synthesis. MMPs also destroy the basement membrane, which is involved in skin elasticity. The extracellular matrix vitalizer RATM (RA) contains various antioxidants and sodium hyaluronate, which lead to skin rejuvenation. We evaluated whether RA decreases oxidative stress and mitochondrial dysfunction, eventually increasing skin elasticity in aged animals. Oxidative stress was assessed by assaying NADPH oxidase activity, which is involved in ROS generation, and the expression of SOD, which removes ROS. NADPH oxidase activity was increased in aged skin and decreased by RA injection. SOD expression was decreased in aged skin and increased by RA injection. Damage to mitochondrial DNA and mitochondrial fusion markers was increased in aged skin and decreased by RA. The levels of mitochondrial biogenesis markers and fission markers were decreased in aged skin and increased by RA. The levels of NF-κB/AP-1 and MMP1/2/3/9 were increased in aged skin and decreased by RA. The levels of TGF-β, CTGF, and collagen I/III were decreased in aged skin and increased by RA. The expression of laminin and nidogen and basement membrane density were decreased in aged skin and increased by RA. RA increased collagen fiber accumulation and elasticity in aged skin. In conclusion, RA improves skin rejuvenation by decreasing oxidative stress and mitochondrial dysfunction in aged skin.

Dopamine D1 receptor activation ameliorates ox-LDL-induced endothelial cell senescence via CREB/Nrf2 pathway

Endothelial cell senescence is involved in endothelial dysfunction and aging-related vascular diseases. The D1-like dopamine receptor (DR1), a number of G-protein-coupled receptors, is currently under consideration as a potential therapeutic target for the prevention of atherosclerosis. However, the role of DR1 in regulating ox-LDL-stimulated endothelial cell senescence remains unknown. Here, we found that the elevated Prx hyperoxidation and reactive oxygen species (ROS) levels in ox-LDL-treated Human umbilical vein endothelial cells (HUVECs) were observed, suppressed by DR1 agonist SKF38393. Increased proportion of senescence-associated β-galactosidase (SA-β-gal) positive staining cells and activated p16/p21/p53 pathway in ox-LDL-treated HUVECs were significantly abolished by DR1 activation. In addition, SKF38393 increased the phosphorylation of cAMP response element-binding protein (CREB) at serine-133, nuclear accumulation of nuclear factor erythroid 2-related factor 2 (Nrf2) and expression of HO-1 in HUVECs. In contrast, adding H-89, a PKA inhibitor, diminished the effects of DR1 activation. Further studies performed with DR1 siRNA confirmed that DR1 was involved in CREB/Nrf2 pathway. Taken together, DR1 activation reduces ROS production and cell senescence by upregulating CREB/Nrf2 antioxidant signaling in ox-LDL-induced endothelial cells. Thus, DR1 could be a potential molecular target to counteract oxidative stress-induced cellular senescence.

Oxidative stress impairs the Nur77-Sirt1 axis resulting in a decline in organism homeostasis during aging.

Sirt1 is an NAD+ -dependent deacetylase that protects against premature aging and cell senescence. Aging accompanied by oxidative stress leads to a decrease in Sirt1 levels and activity, but the regulatory mechanism that connects these events remains unclear. Here, we reported that Nur77, which shares similar biological pathways with Sirt1, was also decreased with age in multiple organs. Our in vivo and in vitro results revealed that Nur77 and Sirt1 decreased during aging and oxidative stress-induced cell senescence. Deletion of Nr4a1 shortened the lifespan and accelerated the aging process in multiple mouse tissues. Overexpression of Nr4a1 protected the Sirt1 protein from proteasomal degradation through negative transcriptional regulation of the E3 ligase MDM2. Our results showed that Nur77 deficiency markedly aggravated aging-related nephropathy and elucidated a key role for Nur77 in the stabilization of Sirt1 homeostasis during renal aging. We proposed a model wherein a reduction of Nur77 in response to oxidative stress promotes Sirt1 protein degradation through MDM2, which triggers cell senescence. This creates additional oxidative stress and provides positive feedback for premature aging by further decreasing Nur77 expression. Our findings reveal the mechanism by which oxidative stress reduces Sirt1 expression during aging and offers an attractive therapeutic strategy for targeting aging and homeostasis in organisms.

β-Cryptoxanthin Maintains Mitochondrial Function by Promoting NRF2 Nuclear Translocation to Inhibit Oxidative Stress-Induced Senescence in HK-2 Cells.

The mechanisms of acute kidney injury and chronic kidney disease remain incompletely revealed, and drug development is a pressing clinical challenge. Oxidative stress-induced cellular senescence and mitochondrial damage are important biological events in a variety of kidney diseases. As a type of carotenoid, β-Cryptoxanthin (BCX) has various biological functions, which means it is a potential therapeutic candidate for the treatment of kidney disease. However, the role of BCX in the kidney is unclear, and the effect of BCX on oxidative stress and cellular senescence in renal cells is also unknown. Therefore, we conducted a series of studies on human renal tubular epithelial (HK-2) cells in vitro. In the present study, we investigated the effect of BCX pretreatment on H2O2-induced oxidative stress and cellular senescence and explored the potential mechanism of BCX action. The results showed that BCX attenuated H2O2-induced oxidative stress and cellular senescence in HK-2 cells. Moreover, BCX promoted NRF2 nuclear expression, maintained mitochondrial function, and reduced mitochondrial damage in HK-2 cells. In addition, silencing NRF2 altered the protective effect of BCX on mitochondria and significantly reversed the anti-oxidative stress and anti-senescence effects of BCX in HK-2 cells. We concluded that BCX maintained mitochondrial function by promoting NRF2 nuclear translocation to inhibit oxidative stress-induced senescence in HK-2 cells. In light of these findings, the application of BCX might be a promising strategy for the prevention and treatment of kidney diseases.

Possible Mechanisms of Oxidative Stress-Induced Skin Cellular Senescence, Inflammation, and Cancer and the Therapeutic Potential of Plant Polyphenols.

As the greatest defense organ of the body, the skin is exposed to endogenous and external stressors that produce reactive oxygen species (ROS). When the antioxidant system of the body fails to eliminate ROS, oxidative stress is initiated, which results in skin cellular senescence, inflammation, and cancer. Two main possible mechanisms underlie oxidative stress-induced skin cellular senescence, inflammation, and cancer. One mechanism is that ROS directly degrade biological macromolecules, including proteins, DNA, and lipids, that are essential for cell metabolism, survival, and genetics. Another one is that ROS mediate signaling pathways, such as MAPK, JAK/STAT, PI3K/AKT/mTOR, NF-κB, Nrf2, and SIRT1/FOXO, affecting cytokine release and enzyme expression. As natural antioxidants, plant polyphenols are safe and exhibit a therapeutic potential. We here discuss in detail the therapeutic potential of selected polyphenolic compounds and outline relevant molecular targets. Polyphenols selected here for study according to their structural classification include curcumin, catechins, resveratrol, quercetin, ellagic acid, and procyanidins. Finally, the latest delivery of plant polyphenols to the skin (taking curcumin as an example) and the current status of clinical research are summarized, providing a theoretical foundation for future clinical research and the generation of new pharmaceuticals and cosmetics.

Nupr1 deficiency downregulates HtrA1, enhances SMAD1 signaling, and suppresses age-related bone loss in male mice.

Nuclear protein 1 (NUPR1) is a stress-induced protein activated by various stresses, such as inflammation and oxidative stress. We previously reported that Nupr1 deficiency increased bone volume by enhancing bone formation in 11-week-old mice. Analysis of differentially expressed genes between wild-type (WT) and Nupr1-knockout (Nupr1-KO) osteocytes revealed that high temperature requirement A 1 (HTRA1), a serine protease implicated in osteogenesis and transforming growth factor-βsignaling was markedly downregulated in Nupr1-KO osteocytes. Nupr1 deficiency also markedly reduced HtrA1 expression, but enhanced SMAD1 signaling in in vitro-cultured primary osteoblasts. In contrast, Nupr1 overexpression enhanced HtrA1 expression in osteoblasts, suggesting that Nupr1 regulates HtrA1 expression, thereby suppressing osteoblastogenesis. Since HtrA1 is also involved in cellular senescence and age-related diseases, we analyzed aging-related bone loss in Nupr1-KO mice. Significant spine trabecular bone loss was noted in WT male and female mice during 6-19 months of age, whereas aging-related trabecular bone loss was attenuated, especially in Nupr1-KO male mice. Moreover, cellular senescence-related markers were upregulated in the osteocytes of 6-19-month-old WT male mice but markedly downregulated in the osteocytes of 19-month-old Nupr1-KO male mice. Oxidative stress-induced cellular senescence stimulated Nupr1 and HtrA1 expression in in vitro-cultured primary osteoblasts, and Nupr1 overexpression enhanced p16ink4a expression in osteoblasts. Finally, NUPR1 expression in osteocytes isolated from the bones of patients with osteoarthritis was correlated with age. Collectively, these results indicate that Nupr1 regulates HtrA1-mediated osteoblast differentiation and senescence. Our findings unveil a novel Nupr1/HtrA1 axis, which may play pivotal roles in bone formation and age-related bone loss.

Cocoa Polyphenol Extract Inhibits Cellular Senescence via Modulation of SIRT1 and SIRT3 in Auditory Cells.

Cocoa, rich in polyphenols, has been reported to provide many health benefits due to its antioxidant properties. In this study, we investigated the effect of Cocoa polyphenols extract (CPE) against oxidative stress-induced cellular senescence using a hydrogen peroxide (H2O2)-induced cellular senescence model in three auditory cells lines derived from the auditory organ of a transgenic mouse: House Ear Institute-Organ of Corti 1 (HEI-OC1), Organ of Corti-3 (OC-k3), and Stria Vascularis (SV-k1) cells. Our results showed that CPE attenuated senescent phenotypes, including senescence-associated β-galactosidase expression, cell proliferation, alterations of morphology, oxidative DNA damage, mitochondrial dysfunction by inhibiting mitochondrial reactive oxygen species (mtROS) generation, and related molecules expressions such as forkhead box O3 (FOXO3) and p53. In addition, we determined that CPE induces expression of sirtuin 1 (SIRT1) and sirtuin 3 (SIRT3), and it has a protective role against cellular senescence by upregulation of SIRT1 and SIRT3. These data indicate that CPE protects against senescence through SIRT1, SIRT3, FOXO3, and p53 in auditory cells. In conclusion, these results suggest that Cocoa has therapeutic potential against age-related hearing loss (ARHL).

Inhibition of Klf10 Attenuates Oxidative Stress-Induced Senescence of Chondrocytes via Modulating Mitophagy.

Osteoarthritis (OA) is the most prevalent degenerative joint disease in the elderly. Accumulation of evidence has suggested that chondrocyte senescence plays a significant role in OA development. Here, we show that Krüppel-like factor 10 (Klf10), also named TGFβ inducible early gene-1 (TIEG1), is involved in the pathology of chondrocyte senescence. Knocking down the Klf10 in chondrocytes attenuated the tert-butyl hydroperoxide (TBHP)-induced senescence, inhibited generation of reactive oxygen species (ROS), and maintained mitochondrial homeostasis by activating mitophagy. These findings suggested that knocking down Klf10 inhibited senescence-related changes in chondrocytes and improved cartilage homeostasis, indicating that Klf10 may be a therapeutic target for protecting cartilage against OA.

Comparative assessment of Cucurbita moschata seed polypeptides toward the protection of human skin cells against oxidative stress-induced aging.

Skin aging has attracted much attention among the current aging population of society. The seeds of Cucurbita moschata possess a variety of potential biological activities as a healthy diet. However, limited information is available on the skin-antiaging properties of C. moschata seed protein and its hydrolysate. Herein, we developed a novel strategy for protecting human skin cells against oxidative stress-induced aging by C. moschata seed polypeptides. C. moschata seed polypeptides (CSPs) with different molecular weight distributions were successfully prepared by controlling the protease hydrolysis time. The proportions of < 1,000 Da polypeptides of P-1, P-2, and P-3 were 0.11, 20.26, and 92.72%, respectively. P-3 contained the highest proportion of polypeptides of size < 1,000 Da, which was observed to promote human skin fibroblast (HSF) growth by MTT assay, cell cycle, and morphology. P-3 has an efficient repair effect on the H2O2-induced aging of HSF cells. To explain this phenomenon, cell lifespan, intracellular ROS level, superoxide dismutase (SOD) activity, and glutathione (GSH) content were investigated to reveal the interactions between P-3 and antiaging. With the increase in P-3 concentration, the ROS level significantly decreased, and the SOD activity and GSH content significantly increased in H2O2-induced HSF cells. These findings indicated that CSPs have the potential to inhibit skin aging, which could be advantageous in the health industry for providing personal care.

PS-BPB01-9: OMEGA-3 FATTY ACIDS ATTENUATE OXIDATIVE STRESS-INDUCED DNA DAMAGE THROUGH NRF-2 IN VASCULAR ENDOTHELIAL CELLS

Objective: Impaired vasodilation is one of the characterizations of hypertension. The effects of the omega-3 fatty acids on blood pressure and vascular function have been examined in many randomized controlled trials. In this study, we investigated the effects of omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), on DNA damage, which has crucial effects on vascular endothelial cell function. Design and method: We examined the effects of EPA and DHA on H2O2-induced DNA damage response in human aortic endothelial cells (HAECs). DNA double-strand breaks (DSBs) were detected by immunofluorescence staining of the phosphorylated form of the histone H2AX (gamma-H2AX). Results: EPA and DHA significantly reduced accumulation of DSBs and phosphorylation of ATM, a serine/threonine kinase recruited and activated upon DSBs, in HAECs. Since EPA and DHA attenuated DNA damage without enhancement of DNA repair response, the effects of EPA and DHA on oxidative stress, a DNA damage inducer, were examined. CM-H2DCFDA measurement showed that EPA and DHA significantly reduced intracellular reactive oxygen species. In addition, mRNA levels of antioxidant molecules, such as heme oxygenase-1 and thioredoxin reductase 1, were significantly elevated by EPA and DHA. Silencing the gene encoding nuclear factor erythroid 2-related factor 2 (Nrf2) abrogated these increases. Furthermore, EPA and DHA reduced H2O2-induced senescence-associated beta-galactosidase activity, which was revoked by Nrf2 silencing. Conclusions: Our results suggest that EPA and DHA attenuate oxidative stress-induced DNA damage and cell senescence in vascular endothelial cells partly via antioxidant response mediated by Nrf-2. Therefore EPA and DHA may play a role in the prevention of impairment in vasodilation by their genome-protective properties.