Oxidative Stress-induced Senescence Research Articles

High Ammonia Nitrogen-Induced Reproductive Toxicity in Goldfish (Carassius auratus) Mature Ovary

Ammonia nitrogen is one of the major pollutants in aquaculture. However, the mechanism of ammonia stress on ovarian development and follicular atresia is unknown. In this study, goldfish (Carassius auratus) were exposed to different ammonia concentrations, including 0 (control, C) and 50 mg/L (high, H) for 48 hr at 21 ± 0.5°C. Histology of the ovarian tissue sections revealed that the high ammonia concentrations inhibited the maturation of oocytes, and induced broken and wrinkled radiation bands, follicular membranes, and the accumulation of rod-shaped yolk particles. From the transcriptome data, a total of 1,405 differentially expressed genes (DEGs) were detected between H and C groups. Most DEGs were highly enriched in low-density lipoprotein particle-mediated signaling, oxidative stress-induced premature senescence, and ovarian steroidogenesis pathway. Furthermore, a total of 19 genes were selected and determined by quantitative real-time polymerase chain reaction (qRT-PCR). The changes in oxidative stress and antioxidant activity indicated the excessive accumulation of reactive oxygen species (ROS) in ovarian tissue. The ovarian apoptosis was induced in the H group. The downregulation of genes involved in the ovarian steroidogenesis pathway indicated that ammonia nitrogen stress prevented the synthesis of sexual hormones. These results suggest that high-concentration ammonia stress induces ovarian damage in goldfish, affecting its antioxidant function, leading to excessive ROS accumulation, ovarian apoptosis, and hindered steroid synthesis, adversely affecting reproductive performance.

Senescence of endothelial cells promotes phenotypic changes in adventitial fibroblasts: possible implications for vascular aging.

Aging is the most important risk factor for the development of cardiovascular diseases. Senescent cells release plethora of factors commonly known as the senescence-associated secretory phenotype, which can modulate the normal function of the vascular wall. It is currently not well understood if and how endothelial cell senescence can affect adventitial niche. The aim of this study was to characterize oxidative stress-induced endothelial cells senescence and identify their paracrine effects on the primary cell type of the adventitia, the fibroblasts. Human aortic endothelial cells (HAEC) were treated with hydrogen peroxide to induce premature senescence. Mass spectrometry analysis identified several proteomic changes in senescent HAEC with top upregulated secretory protein growth differentiation factor 15 (GDF-15). Treatment of the human adventitial fibroblast cell line (hAdv cells) with conditioned medium (CM) from senescent HAEC resulted in alterations in the proteome of hAdv cells identified in mass spectrometry analysis. Majority of differentially expressed proteins in hAdv cells treated with CM from senescent HAEC were involved in the uptake and metabolism of lipoproteins, mitophagy and ferroptosis. We next analyzed if some of these changes and pathways might be regulated by GDF-15. We found that recombinant GDF-15 affected some ferroptosis-related factors (e.g. ferritin) and decreased oxidative stress in the analyzed adventitial fibroblast cell line, but it had no effect on erastin-induced cell death. Contrary, silencing of GDF-15 in hAdv cells was protective against this ferroptotic stimuli. Our findings can be of importance for potential therapeutic strategies targeting cell senescence or ferroptosis to alleviate vascular diseases.

Albiflorin Inhibits Advanced Glycation End Products-Induced ROS and MMP-1 Expression in Gingival Fibroblasts.

Periodontitis is a common complication of diabetes, with advanced glycation end products (AGEs) playing a key role in its pathogenesis. Albiflorin, a monoterpene glycoside, has shown potential anti-inflammatory and antioxidant properties. This study aims to investigate the effects of albiflorin on AGEs-induced gingival fibroblasts and its underlying mechanisms. This study aimed to evaluate the role of albiflorin in mitigating ROS production, inflammation, and MMP-1 expression in AGEs-induced gingival fibroblasts. The viability of gingival fibroblasts treated with albiflorin and AGEs was assessed using CCK-8 assays. ROS levels were measured by DCF staining, and the expression of inflammatory markers and MMP-1 was evaluated by ELISA and qPCR. The involvement of the NF-κB and Nrf2 pathways was examined by immunoblotting. Albiflorin enhanced the viability of AGEs-induced gingival fibroblasts and reduced ROS production. It also decreased the expression of IL-6, IL-8, RAGE, and MMP-1, suggesting an anti- inflammatory effect. Mechanistically, albiflorin modulated the NF-κB and Nrf2 pathways in AGEs-induced gingival fibroblasts. Albiflorin exhibited protective effects against AGEs-induced oxidative stress and inflammation in gingival fibroblasts, highlighting its potential as a therapeutic agent for periodontitis in diabetic patients. The modulation of the NF-κB and Nrf2 pathways by albiflorin provides insight into its mechanism of action.

Accelerated Aging Induced by an Unhealthy High-Fat Diet: Initial Evidence for the Role of Nrf2 Deficiency and Impaired Stress Resilience in Cellular Senescence.

High-fat diets (HFDs) have pervaded modern dietary habits, characterized by their excessive saturated fat content and low nutritional value. Epidemiological studies have compellingly linked HFD consumption to obesity and the development of type 2 diabetes mellitus. Moreover, the synergistic interplay of HFD, obesity, and diabetes expedites the aging process and prematurely fosters age-related diseases. However, the underlying mechanisms driving these associations remain enigmatic. One of the most conspicuous hallmarks of aging is the accumulation of highly inflammatory senescent cells, with mounting evidence implicating increased cellular senescence in the pathogenesis of age-related diseases. Our hypothesis posits that HFD consumption amplifies senescence burden across multiple organs. To scrutinize this hypothesis, we subjected mice to a 6-month HFD regimen, assessing senescence biomarker expression in the liver, white adipose tissue, and the brain. Aging is intrinsically linked to impaired cellular stress resilience, driven by dysfunction in Nrf2-mediated cytoprotective pathways that safeguard cells against oxidative stress-induced senescence. To ascertain whether Nrf2-mediated pathways shield against senescence induction in response to HFD consumption, we explored senescence burden in a novel model of aging: Nrf2-deficient (Nrf2+/-) mice, emulating the aging phenotype. Our initial findings unveiled significant Nrf2 dysfunction in Nrf2+/- mice, mirroring aging-related alterations. HFD led to substantial obesity, hyperglycemia, and impaired insulin sensitivity in both Nrf2+/- and Nrf2+/+ mice. In control mice, HFD primarily heightened senescence burden in white adipose tissue, evidenced by increased Cdkn2a senescence biomarker expression. In Nrf2+/- mice, HFD elicited a significant surge in senescence burden across the liver, white adipose tissue, and the brain. We postulate that HFD-induced augmentation of senescence burden may be a pivotal contributor to accelerated organismal aging and the premature onset of age-related diseases.

Expression of Multicopy Tandem Recombinant Ginseng Hexapeptide in Bacillus subtilis and the Evaluation of Antiaging Activity.

Ginseng oligopeptides are naturally occurring small-molecule peptides extracted from ginseng that exhibit positive effects on health and longevity. However, the current industrial production of ginseng oligopeptides primarily relies on plant extraction and chemical synthesis. In this study, we proposed a novel genetic engineering approach to produce active ginseng peptides through multicopy tandem insertion (5 and 15 times). The recombinant ginseng peptides were successfully produced from engineered Bacillus subtilis with an increasing yield from 356.55 to 2900 mg/L as the repeats multiple. Additionally, an oxidative stress-induced aging model caused by H2O2 was established to evaluate whether the recombinant ginseng peptides, without enzymatic hydrolysis into individual peptides, also have positive effects on antiaging. The results demonstrated that all two kinds of recombinant ginseng peptides could also delay cellular aging through various mechanisms, such as inhibiting cell cycle arrest, suppressing the expression of pro-inflammatory factors, and enhancing cellular antioxidant capacity.

Purinergic signaling promotes premature senescence

Extracellular ATP activates P2 purinergic receptors. Whether purinergic signaling is functionally coupled to cellular senescence is largely unknown. We find that oxidative stress induced release of ATP and caused senescence in human lung fibroblasts. Inhibition of P2 receptors limited oxidative stress-induced senescence, while stimulation with exogenous ATP promoted premature senescence. Pharmacological inhibition of P2Y11 receptor (P2Y11R) inhibited premature senescence induced by either oxidative stress or ATP, while stimulation with a P2Y11R agonist was sufficient to induce cellular senescence. Our data show that both extracellular ATP and a P2Y11R agonist induced calcium (Ca++) release from the endoplasmic reticulum (ER) and that either inhibition of phospholipase C or intracellular Ca++ chelation impaired ATP-induced senescence. We also find that Ca++ that was released from the ER, following ATP-mediated activation of phospholipase C, entered mitochondria in a manner dependent on P2Y11R activation. Once in mitochondria, excessive Ca++ promoted the production of reactive oxygen species in a P2Y11R-dependent fashion, which drove development of premature senescence of lung fibroblasts. Finally, we show that conditioned medium derived from senescent lung fibroblasts, which were induced to senesce through the activation of ATP/P2Y11R-mediated signaling, promoted the proliferation of triple-negative breast cancer cells and their tumorigenic potential by secreting amphiregulin. Our study identifies the existence of a novel purinergic signaling pathway that links extracellular ATP to the development of a protumorigenic premature senescent phenotype in lung fibroblasts that is dependent on P2Y11R activation and ER-to-mitochondria calcium signaling.

Uptake of ox-LDL by binding to LRP6 mediates oxidative stress-induced BMSCs senescence promoting obesity-related bone loss

Obesity has long been thought to be a main cause of hyperlipidemia. As a systemic disease, the impact of obesity on organs, tissues and cells is almost entirely negative. However, the relationship between obesity and bone loss is highly controversial. On the one hand, obesity has long been thought to have a positive effect on bone due to increased mechanical loading on the skeleton, conducive to increasing bone mass to accommodate the extra weight. On the other hand, obesity-related metabolic oxidative modification of low-density lipoprotein (LDL) in vivo causes a gradual increase of oxidized LDL (ox-LDL) in the bone marrow microenvironment. We have reported that low-density lipoprotein receptor-related protein 6 (LRP6) acts as a receptor of ox-LDL and mediates the bone marrow stromal cells (BMSCs) uptake of ox-LDL. We detected elevated serum ox-LDL in obese mice. We found that ox-LDL uptake by LRP6 led to an increase of intracellular reactive oxygen species (ROS) in BMSCs, and N-acetyl-L-cysteine (NAC) alleviated the cellular senescence and impairment of osteogenesis induced by ox-LDL. Moreover, LRP6 is a co-receptor of Wnt signaling. We found that LRP6 preferentially binds to ox-LDL rather than dickkopf-related protein 1 (DKK1), both inhibiting Wnt signaling and promoting BMSCs senescence. Mesoderm development LRP chaperone (MESD) overexpression inhibits ox-LDL binding to LRP6, attenuating oxidative stress and BMSCs senescence, eventually rescuing bone phenotype.

Corosolic acid enhances oxidative stress-induced apoptosis and senescence in pancreatic cancer cells by inhibiting the JAK2/STAT3 pathway.

Pancreatic cancer (PC) is a fatal human malignancy with a poor prognosis. Corosolic acid (CRA) is a triterpenoid, has been reported to have inhibitory effects on tumor growth. However, the role of CRA on PC has not been explored. Here, we aimed to uncover the molecular mechanisms of CRA in PC progression. Cell viability, lactate dehydrogenase (LDH) release, cell apoptosis and senescence were detected by cell counting kit-8 (CCK-8), LDH, flow cytometry and senescence associated-β-galactosidase (SA-β-gal) assay. Levels of relevant proteins and oxidative stress (OS) markers were evaluated by Western blot and enzyme-linked immunosorbent assay (ELISA). A xenograft tumor model was established to explore the in vivo effects of CRA on PC. We found that CRA inhibited PC cell viability and promoted LDH release in a dose-dependent manner, but had no significant effect on human normal pancreatic ductal epithelial cells HPDE6C7. CRA increased OS-induced cell apoptosis and senescence in HAPC and SW1990 cells. And CRA decreased the levels of anti-apoptotic protein Bcl-2, and elevated the expression of pro-apoptotic protein Bax and senescence-associated proteins P21 and P53. Besides, CRA decreased tumor growth in xenograft models. Furthermore, CRA inactivated the Janus kinase-2 (JAK2)/Signal Transducer and Activator of Transcription 3 (STAT3) signaling pathway in HAPC and SW1990 cells. Functional experiments demonstrated that activation of the JAK2/STAT3 pathway by the JAK2 activator coumermycin A1 (C-A1) or the STAT3 activator colivelin (col) reduced the contribution effect of OS, apoptosis and senescence by CRA. Taken together, our findings indicated that CRA exerted anti-cancer effects in PC by inhibiting the JAK2/STAT3 pathway.

SRSF7 downregulation induces cellular senescence through generation of MDM2 variants.

Alternative splicing (AS) enables a pre-mRNA to generate different functional protein variants. The change in AS has been reported as an emerging contributor to cellular senescence and aging. However, it remains to be elucidated which senescent AS variants are generated in and regulate senescence. Here, we observed commonly down-regulated SRSF7 in senescent cells, using publicly available RNA-seq datasets of several in vitro senescence models. We further confirmed SRSF7 deregulation from our previous microarray datasets of time-series replicative senescence (RS) and oxidative stress-induced senescence (OSIS) of human diploid fibroblast (HDF). We validated the time-course changes of SRSF mRNA and protein levels, developing both RS and OSIS. SRSF knockdown in HDF was enough to induce senescence, accompanied by p53 protein stabilization and MDM2 variants formation. Interestingly, expression of MDM2 variants showed similar patterns of p53 expression in both RS and OSIS. Next, we identified MDM2-C as a key functional AS variant generated specifically by SRSF7 depletion. Finally, we validated that MDM2-C overexpression induced senescence of HDF. These results indicate that SRSF7 down-regulation plays a key role in p53-mediated senescence by regulating AS of MDM2, a key negative regulator of p53, implying its critical involvement in the entry into cell senescence.

Impaired neuron differentiation in GBA-associated Parkinson’s disease is linked to cell cycle defects in organoids

The mechanisms underlying Parkinson’s disease (PD) etiology are only partially understood despite intensive research conducted in the field. Recent evidence suggests that early neurodevelopmental defects might play a role in cellular susceptibility to neurodegeneration. To study the early developmental contribution of GBA mutations in PD we used patient-derived iPSCs carrying a heterozygous N370S mutation in the GBA gene. Patient-specific midbrain organoids displayed GBA-PD relevant phenotypes such as reduction of GCase activity, autophagy impairment, and mitochondrial dysfunction. Genome-scale metabolic (GEM) modeling predicted changes in lipid metabolism which were validated with lipidomics analysis, showing significant differences in the lipidome of GBA-PD. In addition, patient-specific midbrain organoids exhibited a decrease in the number and complexity of dopaminergic neurons. This was accompanied by an increase in the neural progenitor population showing signs of oxidative stress-induced damage and premature cellular senescence. These results provide insights into how GBA mutations may lead to neurodevelopmental defects thereby predisposing to PD pathology.

Oxymatrine Improves Oxidative Stress-Induced Senescence in HT22 Cells and Mice via the Activation of AMP-Activated Protein Kinase.

The accumulation of oxidative stress is one of the important factors causing cellular senescence. Oxymatrine (OM) is a natural quinolizidine alkaloid compound known for its antioxidant effects. This study aimed to investigate the anti-senescence potential of OM through oxidative stress-induced in vitro and in vivo models. By treating 600 μM of H2O2 to the HT22 mouse hippocampal neuronal cell line and by administering 150 mg/kg D-galactose to mice, we generated oxidative stress-induced senescence models. After providing 1, 2, and 4 μg/mL of OM to the HT22 mouse cell line and by administering 50 mg/kg OM to mice, we evaluated the enhancing effects. We evaluated different senescence markers, AMPK activity, and autophagy, along with DCFH-DA detection reaction and behavioral tests. In HT22 cells, OM showed a protective effect. OM, by reducing ROS and increasing p-AMPK expression, could potentially reduce oxidative stress-induced senescence. In the D-Gal-induced senescence mouse model, both the brain and heart tissues recovered AMPK activity, resulting in reduced levels of senescence. In neural tissue, to assess neurological recovery, including anxiety symptoms and exploration, we used a behavioral test. We also found that OM decreased the expression level of receptors for advanced glycation end products (RAGE). In heart tissue, we could observe the restoration of AMPK activity, which also increased the activity of autophagy. The results of our study suggest that OM ameliorates oxidative stress-induced senescence through its antioxidant action by restoring AMPK activity.

Resistance training up-regulates Smyd1 expression and inhibits oxidative stress and endoplasmic reticulum stress in the heart of middle-aged mice

Persistent oxidative stress and endoplasmic reticulum (ER) stress are the primary mechanisms of age-related cardiovascular diseases. Although exercise training is viewed as an effective anti-aging approach, further exploration is needed to identify the mechanisms and functional targets. In this study, the impact of resistance training (RT) on the expression of Smyd1, the levels of reactive oxygen species (ROS) and the expression of ER stress-related protein in the hearts of mice of different ages were assessed. In addition, the role of Smyd1 in the aging-induced oxidative stress and ER stress were evaluated in d-galactose (D-gal)-treated H9C2 cells. We demonstrated that RT in middle age increased the expression of Smyd1 and restricted heart aging-induced ER stress. Overexpression of Smyd1 restrained oxidative stress and ER stress in D-gal-treated H9C2 cells, while the inhibition of Nrf2 and Smyd1 escalated ER stress. These findings demonstrate that Smyd1 has significant impact in regulating age-related ER stress. RT in middle age can up-regulates Smyd1 expression and inhibits oxidative stress and ER stress in the heart.

Colchicine prevents oxidative stress-induced endothelial cell senescence via blocking NF-κB and MAPKs: implications in vascular diseases

BackgroundSmoking, alcohol abuse, and hypertension are – among others, potential risk factors for cardiovascular diseases. These risk factors generate oxidative stress and cause oxidative stress-induced DNA damage, resulting in cellular senescence and senescence-associated secretory phenotype (SASP). The SASP factors in feed-forward response exacerbate inflammation and cause tissue remodeling, resulting in atherosclerotic plaque formation and rupture.ResultsColchicine inhibited ROS generation and mitigated oxidative stress-induced DNA damage. It dampened oxidative stress-induced endothelial cell senescence and improved the expression of DNA repair protein KU80 and aging marker Lamin B1. The drug attenuated the expression of senescence marker P21 at mRNA and protein levels. The pathway analysis showed that colchicine inhibited NF-κB and MAPKs pathways and subdued mTOR activation. Colchicine also attenuated mRNA expression of interleukin (IL)-1β, IL-6, IL-8, MCP-1, ICAM-1, and E-selectin. Furthermore, colchicine reduced the mRNA and protein expression of matrix metalloproteinase (MMP-2).ConclusionIn summary, colchicine blocked oxidative stress-induced senescence and SASP by inhibiting the activation of NF-κB and MAPKs pathways.Graphical

A food-grade and senescent cell-targeted fisetin delivery system based on whey protein isolate-galactooligosaccharides Maillard conjugate

Cellular senescence is the results of aging and age-related diseases, and the development of anti-aging methods may improve health and extend longevity. The natural flavonol fisetin has been shown to antagonize senescence in vitro and increases longevity in vivo, but has poor water solubility and limited bioavailability. In this study, a food-grade and senescent cell-targeted delivery system for fisetin was developed based on whey protein isolate-galactooligosaccharides (WPI-GOS) Maillard conjugate, which could recognize senescence associated β-galactosidase in senescent cells. The fisetin nanoparticles possessed a high encapsulation efficiency, excellent dispersibility in water, good storage stability and well biocompatibility. Moreover, they could effectively accumulate and retain in senescent cells with excellent senescent cell-targeting efficacy, and inhibit the oxidative stress-induced cellular senescence in vitro. Thus, this novel nanoparticle system based on WPI-GOS Maillard conjugate showed promise to deliver hydrophobic bioactive ingredients like fisetin to senescent cells to improve their bioavailability and anti-senescence effect.

Evaluation of efficacy of Silybum marianum flower extract on the mitigating hair loss in vitro and in vivo.

Natural components that can exert a wide range of anti-hair loss activity with fewer side effects are in high demand. The objective of this study was to investigate the anti-hair loss potential of Silybum marianum flower extract (SMFE) in vitro and in vivo. The effect of SMFE on dermal papilla cells was evaluated by measuring cell proliferation and VEGF production in hair follicle dermal papilla cells (HFDPCs). In addition, to confirm the effect of SMFE on dermal papilla senescence, SA-β-gal staining and senescence associated secretory phenotype (SASP) production such as IL-6 was observed in both replicative and hydrogen peroxide (H2 O2 )-induced senescence models. In a clinical study, hair growth was determined by reconstitution analysis after shaving the hair of the clinical subject's scalp and hair area. SMFE increased the proliferation and VEGF production of HFDPCs. It also suppressed cellular senescence of HFDPCs and IL-6 production in replicative senescence and oxidative stress-induced senescence models. The hair density and total hair count at 16 and 24 weeks after using hair shampoo containing SMFE were significantly increased compared with those of the placebo group. SMFE has the potential to be used as a natural ingredient for alleviating hair loss.

Quercetin ameliorates oxidative stress-induced senescence in rat nucleus pulposus-derived mesenchymal stem cells via the miR-34a-5p/SIRT1 axis.

Intervertebral disc degeneration (IDD) is a main contributor to low back pain. Oxidative stress, which is highly associated with the progression of IDD, increases senescence of nucleus pulposus-derived mesenchymal stem cells (NPMSCs) and weakens the differentiation ability of NPMSCs in degenerated intervertebral discs (IVDs). Quercetin (Que) has been demonstrated to reduce oxidative stress in diverse degenerative diseases. To investigate the role of Que in oxidative stress-induced NPMSC damage and to elucidate the underlying mechanism. In vitro, NPMSCs were isolated from rat tails. Senescence-associated β-galactosidase (SA-β-Gal) staining, cell cycle, reactive oxygen species (ROS), real-time quantitative polymerase chain reaction (RT-qPCR), immunofluorescence, and western blot analyses were used to evaluated the protective effects of Que. Meanwhile the relationship between miR-34a-5p and Sirtuins 1 (SIRT1) was evaluated by dual-luciferase reporter assay. To explore whether Que modulates tert-butyl hydroperoxide (TBHP)-induced senescence of NPMSCs via the miR-34a-5p/SIRT1 pathway, we used adenovirus vectors to overexpress and downregulate the expression of miR-34a-5p and used SIRT1 siRNA to knockdown SIRT1 expression. In vivo, a puncture-induced rat IDD model was constructed, and X rays and histological analysis were used to assess whether Que could alleviate IDD in vivo. We found that TBHP can cause NPMSCs senescence changes, such as reduced cell proliferation ability, increased SA-β-Gal activity, cell cycle arrest, the accumulation of ROS, and increased expression of senescence-related proteins. While abovementioned senescence indicators were significantly alleviated by Que treatment. Que decreased the expression levels of senescence-related proteins (p16, p21, and p53) and senescence-associated secreted phenotype (SASP), including IL-1β, IL-6, and MMP-13, and it increased the expression of SIRT1. In addition, the protective effects of Que on cell senescence were partially reversed by miR-34a-5p overexpression and SIRT1 knockdown. In vivo, X-ray, and histological analyses indicated that Que alleviated IDD in a puncture-induced rat model. In summary, the present study provides evidence that Que reduces oxidative stress-induced senescence of NPMSCs via the miR-34a/SIRT1 signaling pathway, suggesting that Que may be a potential agent for the treatment of IDD.

ISG15–USP18 Dysregulation by Oxidative Stress Promotes IFN-γ Secretion from CD8+ T Cells in Vitiligo

Excessive oxidative stress is thought to play pathologic roles in cellular senescence and autoimmune disorders by inducing inflammation and breaking down immune tolerance. In this study, we sought to identify the factors linking oxidative stress to autoimmunity and cellular senescence in vitiligo, where elevated oxidative stress plays an important role. RNA sequencing analysis of hydrogen peroxide-treated melanocytes revealed upregulation of ISG15. The upregulation of ISG15 was observed in vitiligo skin tissues as well as in the blood of patients with vitiligo, whereas USP18 downregulation was observed in vitiligo melanocytes and vitiligo skin tissues. Oxidative stress induced hypermethylation of the USP18 promoter region in keratinocytes and melanocytes, and USP18 promoter hypermethylation was also confirmed in vitiligo skin tissues. Our results indicate that USP18 promoter hypermethylation caused by oxidative stress increases ISG15 expression in keratinocytes and melanocytes along with senescence changes, leading CD8+ T cells to produce IFN-γ, the main pathogenic cytokine in vitiligo. Therefore, the ISG15-USP18 network may be important in oxidative stress-induced autoimmunity and cellular senescence in vitiligo pathogenesis.

Anti-aging formula protects skin from oxidative stress-induced senescence through the inhibition of CXCR2 expression

Ethnopharmacological relevanceThe skin is affected by endogenous and exogenous factors, which are the intuitive consequence expression of aging. Aging not only affects the aesthetics of the skin but also causes the decline of skin functions, leading to many skin diseases and even skin cancer. Anti-aging formula (AAF) has various biological effects such as antioxidants, regulation of intestinal flora metabolism, anti-aging, and memory improvement. However, it is not clarified whether it could be anti-aging of the skin and the anti-aging mechanism. Aim of the studyThis study aimed to investigate whether AAF could prevent skin from oxidative stress-induced senescence and explore the underlying molecular mechanisms. Materials and methodsA mouse skin oxidative stress aging model was established based on ultraviolet (UV) irradiation, and parameters such as skin water content, melanogenesis, wrinkle production, pathological changes, and aging marker proteins were measured to elucidate whether AAF has an anti-aging effect on the skin. Subsequently, transcriptome sequencing (RNA-Seq) was used to identify target genes. An in vitro cellular senescence model was established to assess the role of AAF against cellular oxidative stress senescence by detecting senescence-related markers, while the specific mechanism of action of AAF in delaying skin senescence was elucidated by silencing or overexpression of targets. ResultsIn vivo experiments demonstrated that AAF significantly increased skin water content, reduced skin sensitivity and melanin content, slowed wrinkles, improved UV-induced epidermal thickening, increased collagen fiber content, improved elastic fiber morphology, and reduced the expression of senescence proteins P21 and P16 in skin tissues. The RNA-Seq results identified chemokine receptor 2 (CXCR2) as one of the potential targets for delaying skin senescence. In vitro experiments showed that AAF markedly improved the aging phenotype, and knockdown or overexpression experiments verified the essential role of CXCR2 in the skin senescence process. Mechanistic studies suggested that AAF inhibited the P38/P53 pathway by reducing CXCR2 expression, which improved the aging phenotype, reduced oxidative damage, and ultimately delayed cellular senescence. ConclusionThe results reveal that AAF protects skin from oxidative stress-induced senescence by regulating the expression of critical target CXCR2, reducing P38 protein phosphorylation, and inhibiting P53 pathway activation. These discoveries implicate the potential of AAF in the protection of skin aging disease.

Mass Cytometry as a Tool for Investigating Senescence in Multiple Model Systems.

Cellular senescence is a durable cell cycle arrest as a result of the finite proliferative capacity of cells. Senescence responds to both intrinsic and extrinsic cellular stresses, such as aging, mitochondrial dysfunction, irradiation, and chemotherapy. Here, we report on the use of mass cytometry (MC) to analyze multiple model systems and demonstrate MC as a platform for senescence analysis at the single-cell level. We demonstrate changes to p16 expression, cell cycling fraction, and histone tail modifications in several established senescent model systems and using isolated human T cells. In bone marrow mesenchymal stromal cells (BMSCs), we show increased p16 expression with subsequent passage as well as a reduction in cycling cells and open chromatin marks. In WI-38 cells, we demonstrate increased p16 expression with both culture-induced senescence and oxidative stress-induced senescence (OSIS). We also use Wanderlust, a trajectory analysis tool, to demonstrate how p16 expression changes with histone tail modifications and cell cycle proteins. Finally, we demonstrate that repetitive stimulation of human T cells with CD3/CD28 beads induces an exhausted phenotype with increased p16 expression. This p16-expressing population exhibited higher expression of exhaustion markers such as EOMES and TOX. This work demonstrates that MC is a useful platform for studying senescence at a single-cell protein level, and is capable of measuring multiple markers of senescence at once with high confidence, thereby improving our understanding of senescent pathways.

A Novel Role of Hyaluronic Acid and Proteoglycan Link Protein 1 (HAPLN1) in Delaying Vascular Endothelial Cell Senescence.

Cardiovascular diseases (CVDs) are the most common cardiovascular system disorders. Cellular senescence is a key mechanism associated with dysfunction of aged vascular endothelium. Hyaluronic acid and proteoglycan link protein 1 (HAPLN1) has been known to non-covalently link hyaluronic acid (HA) and proteoglycans (PGs), and forms and stabilizes HAPLN1-containing aggregates as a major component of extracellular matrix. Our previous study showed that serum levels of HAPLN1 decrease with aging. Here, we found that the HAPLN1 gene expression was reduced in senescent human umbilical vein endothelial cells (HUVECs). Moreover, a recombinant human HAPLN1 (rhHAPLN1) decreased the activity of senescence-associated β-gal and inhibited the production of senescence-associated secretory phenotypes, including IL-1β, CCL2, and IL-6. rhHAPLN1 also down-regulated IL-17A levels, which is known to play a key role in vascular endothelial senescence. In addition, rhHAPLN1 protected senescent HUVECs from oxidative stress by reducing cellular reactive oxygen species levels, thus promoting the function and survival of HUVECs and leading to cellular proliferation, migration, and angiogenesis. We also found that rhHAPLN1 not only increases the sirtuin 1 (SIRT1) levels, but also reduces the cellular senescence markers levels, such as p53, p21, and p16. Taken together, our data indicate that rhHAPLN1 delays or inhibits the endothelial senescence induced by various aging factors, such as replicative, IL-17A, and oxidative stress-induced senescence, thus suggesting that rhHAPLN1 may be a promising therapeutic for CVD and atherosclerosis.