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1.
Retinal degeneration diseases (RDDs) are common and devastating eye diseases characterized by the degeneration of photoreceptors, which are highly associated with oxidative stress. Previous studies reported that mitochondrial dysfunction is associated with various neurodegenerative diseases. However, the role of mitochondrial proteostasis mainly regulated by mitophagy and mitochondrial unfolded protein response (mtUPR) in RDDs is unclear. We hypothesized that the mitochondrial proteostasis is neuroprotective against oxidative injury in RDDs. In this study, the data from our hydrogen peroxide (H 2O 2)-treated mouse retinal cone cell line (661w) model of RDDs showed that nicotinamide riboside (NR)-activated mitophagy increased the expression of LC3B II and PINK1, and promoted the co-localization of LC3 and mitochondria, as well as PINK1 and Parkin in the H 2O 2-treated 661w cells. However, the NR-induced mitophagy was remarkably reversed by chloroquine (CQ) and cyclosporine A (CsA), mitophagic inhibitors. In addition, doxycycline (DOX), an inducer of mtUPR, up-regulated the expression of HSP60 and CHOP, the key proteins of mtUPR. Activation of both mitophagy and mtUPR increased the cell viability and reduced the level of apoptosis and oxidative damage in the H 2O 2-treated 661w cells. Furthermore, both mitophagy and mtUPR played a protective effect on mitochondria by increasing mitochondrial membrane potential and maintaining mitochondrial mass. By contrast, the inhibition of mitophagy by CQ or CsA reversed the beneficial effect of mitophagy in the H 2O 2-treated 661w cells. Together, our study suggests that the mitophagy and mtUPR pathways may serve as new therapeutic targets to delay the progression of RDDs through enhancing mitochondrial proteostasis.Subject terms: Cell death, Diseases 相似文献
3.
Kallistatin, a plasma protein, protects against vascular and organ injury. This study is aimed to investigate the role and mechanism of kallistatin in endothelial senescence. Kallistatin inhibited H 2O 2‐induced senescence in human endothelial cells, as indicated by reduced senescence‐associated‐β‐galactosidase activity, p16 INK4a and plasminogen activator inhibitor‐1 expression, and elevated telomerase activity. Kallistatin blocked H 2O 2‐induced superoxide formation, NADPH oxidase levels and VCAM‐1, ICAM‐1, IL‐6 and miR‐34a synthesis. Kallistatin reversed H 2O 2‐mediated inhibition of endothelial nitric oxide synthase (eNOS), SIRT1, catalase and superoxide dismutase (SOD)‐2 expression, and kallistatin alone stimulated the synthesis of these antioxidant enzymes. Moreover, kallistatin's anti‐senescence and anti‐oxidant effects were attributed to SIRT1‐mediated eNOS pathway. Kallistatin, via interaction with tyrosine kinase, up‐regulated Let‐7g, whereas Let‐7g inhibitor abolished kallistatin's effects on miR‐34a and SIRT1/eNOS synthesis, leading to inhibition of senescence, oxidative stress and inflammation. Furthermore, lung endothelial cells isolated from endothelium‐specific kallistatin knockout mice displayed marked reduction in mouse kallistatin levels. Kallistatin deficiency in mouse endothelial cells exacerbated senescence, oxidative stress and inflammation compared to wild‐type mouse endothelial cells, and H 2O 2 treatment further magnified these effects. Kallistatin deficiency caused marked reduction in Let‐7g, SIRT1, eNOS, catalase and SOD‐1 mRNA levels, and elevated miR‐34a synthesis in mouse endothelial cells. These findings indicate that endogenous kallistatin through novel mechanisms protects against endothelial senescence by modulating Let‐7g‐mediated miR‐34a‐SIRT1‐eNOS pathway. 相似文献
5.
Oxidative stress plays a significant role in exacerbation of asthma. The role of vitamin D in oxidative stress and asthma exacerbation remains unclear. We aimed to determine the relationship between vitamin D status and oxidative stress in asthma exacerbation. Severe asthma exacerbation patients with 25-hydroxyvitamin D3-deficiency (V-D deficiency) or 25-hydroxyvitamin D-sufficiency (V-D sufficiency) were enrolled. Severe asthma exacerbation with V-D-deficiency showed lower forced expiratory volume in one second (FEV1) compared to that with V-D-sufficiency. V-D-deficiency intensified ROS release and DNA damage and increased TNF-α, OGG1 and NFκB expression and NFκB phosphorylation in severe asthma exacerbation. Supplemental vitamin D3 significantly increased the rates of FEV1 change and decreased ROS and DNA damage in V-D-deficiency. Vitamin D3 inhibited LPS-induced ROS and DNA damage and were associated with a decline in TNF-α and NFκB in epithelial cells. H 2O 2 reduces nuclear translocation of glucocorticoid receptors in airway epithelial cell lines. V-D pretreatment enhanced the dexamethasone-induced nuclear translocation of glucocorticoid receptors in airway epithelial cell lines and monocytes from 25-hydroxyvitamin D3-deficiency asthma patients. These findings indicate that V-D deficiency aggravates oxidative stress and DNA damage, suggesting a possible mechanism for corticosteroid resistance in severe asthma exacerbation. 相似文献
6.
The mechanisms of sensing and signalling of heat and oxidative stresses are not well understood. The central question of this
paper is whether in plant cells oxidative stress, in particular H 2O 2, is required for heat stress- and heat shock factor (HSF)-dependent expression of genes. Heat stress increases intracellular
accumulation of H 2O 2 in Arabidopsis cell culture. The accumulation was greatly diminished using ascorbate as a scavenger or respectively diphenyleneiodonium
chloride (DPI) as an inhibitor of reactive oxygen species production. The mRNA of heat shock protein (HSP) genes, exemplified
by Hsp17.6, Hsp18.2, and the two cytosolic ascorbate peroxidase genes Apx1, Apx2, reached similar levels by moderate heat stress (37°C) or by treatment with H 2O 2, butylperoxide and diamide at room temperature. The heat-induced expression levels were significantly reduced in the presence
of ascorbate or DPI indicating that H 2O 2 is an essential component in the heat stress signalling pathway. Rapid (15 min) formation of heat shock promoter element
(HSE) protein-binding complex of high molecular weight in extracts of heat-stressed or H 2O 2-treated cells and the inability to form this complex after ascorbate treatment suggests that oxidative stress affects gene
expression via HSF activation and conversely, that H 2O 2 is involved in HSF activation during the early phase of heat stress. The heat stress induction of a high mobility HSE-binding
complex, characteristic for later phase of heat shock response, was blocked by ascorbate and DPI. H 2O 2 was unable to induce this complex suggesting that H 2O 2 is involved only in the early stages of HSF activation. Significant induction of the genes tested after diamid treatment
and moderate expression of the sHSP genes in the presence of 50 mM ascorbate at 37°C occurred without activation of HSF, indicating
that other mechanisms may be involved in stress signalling.
Electronic Supplementary Material Supplementary material is available for this article at http//dx.doi.org/10.1007/s11103-006-0045-4
Roman A. Volkov and Irina I. Panchuk contributed equally 相似文献
7.
It has been reported that selenoprotein W (SelW) mRNA is highly expressed in the developing central nerve system of rats,
and its expression is maintained until the early postnatal stage. We here found that SelW protein significantly increased
in mouse brains of postnatal day 8 and 20 relative to embryonic day 15. This was accompanied by increased expression of SOD1
and SOD2. When the expression of SelW in primary cultured cells derived from embryonic cerebral cortex was knocked down with
small interfering RNAs (siRNAs), SelW siRNA-transfected neuronal cells were more sensitive to the oxidative stress induced
by treatment of H 2O 2 than control cells. TUNEL assays revealed that H 2O 2-induced apoptotic cell death occurred at a higher frequency in the siRNA-transfected cells than in the control cells. Taken
together, our findings suggest that SelW plays an important role in protection of neurons from oxidative stress during neuronal
development. 相似文献
11.
Connective tissue growth factor (CTGF) induces extracellular matrix (ECM) synthesis and contractility in human trabecular meshwork (HTM) cells. Both processes are involved in the pathogenesis of primary open‐angle glaucoma. To date, little is known about regulation and function of CTGF expression in the trabecular meshwork (TM). Therefore, we analysed the effects of different aqueous humour proteins and stressors on CTGF expression in HTM cells. HTM cells from three different donors were treated with endothelin‐1, insulin‐like growth factor (IGF)‐1, angiotensin‐II, H 2O 2 and heat shock and were analysed by immunohistochemistry, real‐time RT‐PCR and Western blotting. Viability after H 2O 2 treatment was measured in CTGF silenced HTM‐N cells and their controls. Latrunculin A reduced expression of CTGF by about 50% compared to untreated HTM cells, whereas endothelin‐1, IGF‐1, angiotensin‐II, heat shock and oxidative stress led to a significant increase. Silencing of CTGF resulted in a delayed expression of αB‐crystallin and in reduced cell viability in comparison to the controls after oxidative stress. Conversely, CTGF treatment led to a higher cell viability rate after H 2O 2 treatment. CTGF expression is induced by factors that have been linked to glaucoma. An increased level of CTGF appears to protect TM cells against damage induced by stress. The beneficial effect of CTGF for viability of TM cells is likely associated with the effects on increased ECM synthesis and higher contractility of the TM, thereby contributing to reduced aqueous humour outflow facility causing increased intraocular pressure. 相似文献
13.
Reactive oxygen species and oxidative stress are associated with neuronal cell death in many neurodegenerative conditions. However, the exact molecular mechanisms triggered by oxidative stress in neurodegeneration are still unclear. This study used the B65 rat neuroblastoma cell line as a model to study the molecular events that occur after H 2O 2 treatment. Treatment of B65 cells with H 2O 2 rapidly up-regulated the DNA damage pathway involved in double-strand breakage. Subsequently, proteins involved in p53 regulation, such as sirtuin 1 and STAT1, were modified. In addition, H 2O 2 treatment altered the pattern of cell cycle protein expression. Specifically, a decrease was found in the expression of cyclin D1, cdk4 and surprisingly the levels of cyclin A and the retinoblastoma protein phosphorylated at ser780 were increased. Furthermore, this study shows that pre-treatment of B65 cells with 50 µM trolox confers almost total protection against apoptotic cell death and restores the cell cycle. Likewise, the increase in retinoblastoma phosphorylation was attenuated by KU-55993, a selective ATM inhibitor, and also by trolox. These observations indicate that DNA damage and oxidative stress are responsible for cell cycle regulation. In summary, this study describes the molecular mechanisms involved in cell cycle alterations induced by oxidative stress in B65 cells. These findings highlight the relevance of ATM in the regulation of cell cycle after oxidative stress. 相似文献
14.
During the progression of osteoarthritis, dysregulation of extracellular matrix (ECM) anabolism, abnormal generation of reactive oxygen species, and proteolytic enzymes have been shown to accelerate the degradation process of cartilage. The purpose of the current study was to investigate the functional role of bromodomain‐containing protein 4 (BRD4) in hydrogen peroxide (H 2O 2)–stimulated chondrocyte injury and delineate the underlying molecular mechanisms. We observed that the expression BRD4 was markedly elevated in rat chondrocytes after H 2O 2 stimulation. Additionally, inhibition of BRD4 using small interfering RNA or JQ1 (a selective potent chemical inhibitor) led to repression of H 2O 2‐induced oxidative stress, as revealed by a decrease in the reactive oxygen species production accompanied by a decreased malondialdehyde content, along with increased activities of antioxidant markers superoxide dismutase, catalase, and glutathione peroxidase on exposure of chondrocytes to H 2O 2. Meanwhile, depletion of BRD4 led to repress the oxidative stress–induced apoptosis of chondrocytes triggered by H 2O 2 accompanied by an increase in the expression of anti‐apoptotic Bcl‐2 and a decrease in the expression of pro‐apoptotic Bax and caspase 3 as well as attenuated caspase 3 activity. Moreover, knockdown of BRD4 or treatment with JQ1 markedly attenuated ECM deposition, reflected in a marked upregulation of proteoglycans collagen type II and aggrecan as well as downregulation of ECM–degrading enzymes matrix metalloproteinase 13 and A disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS‐5). More importantly, inhibition of BRD4‐activated NF‐E2–related factor 2 (Nrf2)–heme oxygenase‐1 signaling. Mechanistically, the protective effect of BRD4 inhibition on H 2O 2‐stimulated apoptosis and cartilage matrix degeneration was markedly abrogated by Nrf2 depletion. Altogether, we concluded that the protective effect of BRD4 inhibition against oxidative stress–mediated apoptosis and cartilage matrix degeneration occurred through Nrf2–heme oxygenase‐1 signaling, implying that BRD4 inhibition may be a more effective therapeutic strategy against osteoarthritis. 相似文献
15.
The active form of vitamin D, 1,25-dihydroxycholecalciferol (1,25(OH)2D3), was reported to improve vascular function in patients with diabetes, yet the underlying mechanisms remain to be fully elucidated. Monoamine oxidase (MAO), a mitochondrial enzyme, with two isoforms (A and B) that generates hydrogen peroxide (H2O2) as by-product, has been recently reported to contribute to the pathogenesis of endothelial dysfunction in diabetes. The present study assessed the interaction between vitamin D and MAO in the vascular wall in the setting of type 1 experimental diabetes. To this aim, diabetes was induced in male Wistar rats via a single injection of streptozotocin (STZ, 50 mg/kg, IP) and 1 month later thoracic aortas were harvested and used for organ bath studies and H2O2 measurements. MAO expression was assessed by immunohistochemistry and RT-PCR. Endothelial function was evaluated in isolated aortic rings in the absence vs. presence of 1,25(OH)2D3 (100 nM, 24 h incubation). In diabetic animals, we found a significant reduction in the endothelial-dependent relaxation to acetylcholine and an increased expression of the MAO-A isoform, respectively. Vitamin D significantly improved vascular function, mitigated oxidative stress and decreased MAO-A expression in diabetic vascular preparations. In conclusion, MAO-A is induced in diabetic aortas and vitamin D can improve diabetes-induced endothelial dysfunction by modulating the MAO-A expression. 相似文献
16.
Parkinson’s disease (PD) is a neurodegenerative disorder characterized by a progressive loss of dopaminergic neurons in the substantia nigra (SN). The present study was designed to examine the therapeutic effect of hydrogen sulfide (H 2S, a novel biological gas) on PD. The endogenous H 2S level was markedly reduced in the SN in a 6‐hydroxydopamine (6‐OHDA)‐induced PD rat model. Systemic administration of NaHS (an H 2S donor) dramatically reversed the progression of movement dysfunction, loss of tyrosine‐hydroxylase positive neurons in the SN and the elevated malondialdehyde level in injured striatum in the 6‐OHDA‐induced PD model. H 2S specifically inhibited 6‐OHDA evoked NADPH oxidase activation and oxygen consumption. Similarly, administration of NaHS also prevented the development of PD induced by rotenone. NaHS treatment inhibited microglial activation in the SN and accumulation of pro‐inflammatory factors (e.g. TNF‐α and nitric oxide) in the striatum via NF‐κB pathway. Moreover, significantly less neurotoxicity was found in neurons treated with the conditioned medium from microglia incubated with both NaHS and rotenone compared to that with rotenone only, suggesting that the therapeutic effect of NaHS was, at least partially, secondary to its suppression of microglial activation. In summary, we demonstrate for the first time that H 2S may serve as a neuroprotectant to treat and prevent neurotoxin‐induced neurodegeneration via multiple mechanisms including anti‐oxidative stress, anti‐inflammation and metabolic inhibition and therefore has potential therapeutic value for treatment of PD. 相似文献
18.
Aim: To develop a faster and easier in vivo method to screen compounds for anti‐oxidant activity using a microbial system. Methods and Results: Bacterial redox sensor‐based assay systems were applied. The activities of SoxR and OxyR, the bacterial redox sensors, were monitored to probe the intracellular redox status through two reporter strains, Escherichia coli soxSp‐ lacZ and oxySp‐ lacZ fusions, which specifically respond to paraquat, a superoxide generator, and H 2O 2, respectively, with practically no cross reactivity. For the test screening, 27 natural compounds including phenolics and flavonoids that are putatively considered anti‐oxidant nutritional supplements were collected and assayed for their capability to alleviate oxidative stress in these bacterial systems. Among them, rutin, kaempferol and quercetin had significant anti‐H 2O 2 activity, and betaine, glycyrrhizic acid and baicalin had weak anti‐superoxide activity. While rutin, kaempferol and quercetin significantly reduced the H 2O 2 stress at low concentrations, betaine, glycyrrhizic acid and baicalin required higher concentration for their anti‐superoxide effects. In vitro, only quercetin protected DNA in a metal‐catalysed oxidation system, suggesting that the other compounds might indirectly exert their anti‐oxidant activities through other biological functions. Finally, quercetin, rutin and kaempferol significantly restored the viability of a superoxide dismutase mutant that has limited viability because of defective defence against oxidative stress. Conclusion: These bacterial systems could provide a more efficient method for measuring the activity of compounds affecting cellular oxidative stress and viability. Significance and Impact of the Study: The demand for anti‐oxidant and anti‐ageing activities is increasing in one of the fastest growing segments of the functional food market, but the screening for these activities is currently very laborious, expensive and time consuming. This study suggests a basis for a high throughput screening method for these activities. 相似文献
19.
Oxidative stress is a major cause of cellular injury in a variety of human diseases including neurodegenerative disorders. Thus, removal of excessive reactive oxygen species (ROS) or suppression of ROS generation may be effective in preventing oxidative stress‐induced cell death. This study was designed to investigate the effect of icariside II (ICS II), a novel phosphodiesterase 5 inhibitor, on hydrogen peroxide (H 2O 2)‐induced death of highly differentiated rat neuronal PC12 cells, and to further examine the underlying mechanisms. We found that ICS II pre‐treatment significantly abrogated H 2O 2‐induced PC12 cell death as demonstrated by the increase of the number of metabolically active cells and decrease of intracellular lactate dehydrogenase (LDH) release. Furthermore, ICS II inhibited H 2O 2‐induced cell death through attenuating intracellular ROS production, mitochondrial impairment, and activating glycogen synthase kinase‐3β (GSK‐3β) as demonstrated by reduced intracellular and mitochondrial ROS levels, restored mitochondrial membrane potential (MMP), decreased p‐tyr216‐GSK‐3β level and increased p‐ser9‐GSK‐3β level respectively. The GSK‐3β inhibitor SB216763 abrogated H 2O 2‐induced cell death. Moreover, ICS II significantly inhibited H 2O 2‐induced autophagy by the reducing autophagosomes number and the LC3‐II/LC3‐I ratio, down‐regulating Beclin‐1 expression, and up‐regulating p62/SQSTM1 and HSP60 expression. The autophagy inhibitor 3‐methyl adenine (3‐MA) blocked H 2O 2‐induced cell death. Altogether, this study demonstrated that ICS II may alleviate oxidative stress‐induced autophagy in PC12 cells, and the underlying mechanisms are related to its antioxidant activity functioning via ROS/GSK‐3β/mitochondrial signalling pathways. 相似文献
20.
Oxidative stress has an important role in neurodegenerative diseases and cerebral ischemic injury. It is reported that d-β-hydroxybutyrate (DβHB), the major component of ketone bodies, is neuroprotective in recent studies. Therefore, in the present work the neuroprotective effects of DβHB on H 2O 2-induced apoptosis mediated by oxidative stress was investigated. PC12 cells were exposed to H 2O 2 with different concentrations of H 2O 2 for different times after DβHB pretreatment. MTT assay, apoptotic rates, intracellular reactive oxygen species (ROS) level, GSH content, mitochondrial membrane potential (MMP) and caspase-3 activity were determined. The results showed that DβHB inhibited the decrease of cell viability induced by H 2O 2 in PC12 cells. DβHB decreased the apoptotic rates induced by H 2O 2. The changes of intracellular ROS, GSH, MMP and caspase-3 activity due to H 2O 2 exposure were partially reversed in PC12 cells. So DβHB inhibited the apoptosis of PC12 cells induced by H 2O 2 via inhibiting oxidative stress. 相似文献
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