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1.
Chloride channel activity is one of the critical factors responsible for cell apoptotic volume decrease (AVD). However, the roles of chloride channels in apoptosis have not been fully understood. In the current study, we assessed the role of chloride channels in hydrogen peroxide (H 2O 2)-induced apoptosis of pheochromocytoma cells (PC12). Extracellular application of H 2O 2 activated a chloride current and induced cell volume decrease in a few minutes. Incubation of cells with H 2O 2 elevated significantly the membrane permeability to the DNA dye Hoechst 33258 in 1 h and induced apoptosis of most PC12 cells tested in 24 h. The chloride channel blocker NPPB (5-nitro-2-(3-phenylpropylamino)-benzoate) prevented appearance of H 2O 2-induced high membrane permeability and cell shrinkage, suppressed H 2O 2-activated chloride currents and protected PC12 cells from apoptosis induced by H 2O 2. The results suggest that chloride channels may contribute to H 2O 2-induced apoptosis by ways of elevation of membrane permeability and AVD in PC12 cells. 相似文献
2.
Transient opening of the mitochondrial permeability transition pore plays a crucial role in hypoxic preconditioning-induced protection. Recently, the cyclophilin-D component of the mitochondrial permeability transition pore has been shown to interact with and regulate the F1F0-ATP synthase. However, the precise role of the F1F0-ATP synthase and the interaction between cyclophilin-D and F1F0-ATP synthase in the mitochondrial permeability transition pore and hypoxic preconditioning remain uncertain. Here we found that a 1-h hypoxic preconditioning delayed apoptosis and improved cell survival after stimulation with various apoptotic inducers including H 2O 2, ionomycin, and arachidonic acid in mitochondrial DNA T8993G mutation (NARP) osteosarcoma 143B cybrids, an F1F0-ATP synthase defect cell model. This hypoxic preconditioning protected NARP cybrid cells against focal laser irradiation-induced oxidative stress by suppressing reactive oxygen species formation and preventing the depletion of cardiolipin. Furthermore, the protective functions of transient opening of the mitochondrial permeability transition pore in both NARP cybrids and wild-type 143B cells can be augmented by hypoxic preconditioning. Disruption of the interaction between cyclophilin-D and F1F0-ATP synthase by cyclosporin A attenuated the mitochondrial protection induced by hypoxic preconditioning in both NARP cybrids and wild-type 143B cells. Our results demonstrate that the interaction between cyclophilin-D and F1F0-ATP synthase is important in the hypoxic preconditioning-induced cell protection. This finding improves our understanding of the mechanism of mitochondrial permeability transition pore opening in cells in response to hypoxic preconditioning, and will be helpful in further developing new pharmacological agents targeting hypoxia–reoxygenation injury and mitochondria-mediated cell death 相似文献
3.
RVF (Arg-Val-Phe), a peptide derived from wheat germ, shows antioxidant properties. Here, the neuroprotective efficacies of RVF were investigated in human neuroblastoma cells (SH-SY5Y) that were pretreated with RVF (150–250 μM, 4 h) and exposed to H 2O 2 (200 μM). RVF increased viable cell numbers by 37 % and reduced the release of lactate dehydrogenase. Pretreatment with RVF also inhibited H 2O 2-induced accumulation of reactive oxygen species and maintained the mitochondrial transmembrane potential as well as preventing intracellular Ca 2+ dysregulation during H 2O 2 exposure. Furthermore, pretreatment with RVF increased the Bcl-2/Bax ratio and blocked cleavage poly(ADP-ribose) polymerase by inhibiting caspase-3 activation, thus decreasing apoptosis. 相似文献
4.
Oxidative stress can induce neuronal apoptosis via the production of superoxide and hydroxyl radicals. This process is as a major pathogenic mechanism in neurodegenerative disorders. In this study, we aimed to clarify whether theaflavins protect PC12 cells from oxidative stress damage induced by H 2O 2. A cell model of PC12 cells undergoing oxidative stress was created by exposing cells to 200 μM H 2O 2 in the presence or absence of varying concentrations of theaflavins (5, 10, and 20 μM). Cell viability was monitored using the MTT assay and Hoechst 33258 staining, showing that 10 μM theaflavins enhanced cell survival following 200 μM H 2O 2 induced toxicity and increased cell viability by approximately 40?%. Additionally, we measured levels of intracellular reactive oxygen species (ROS) and antioxidant enzyme activity. This suggested that the neuroprotective effect of theaflavins against oxidative stress in PC12 cells is derived from suppression of oxidant enzyme activity. Furthermore, Western blot analyses indicated that theaflavins downregulated the ratio of pro-apoptosis/anti-apoptosis proteins Bax/Bcl-2. Theaflavins also downregulated the expression of caspase-3 compared with a H 2O 2-treated group that had not been treated with theaflavins. Interestingly, this is the first study to report that the four main components of theaflavins found in black tea can protect neural cells (PC12) from apoptosis induced by H 2O 2. These findings provide the foundations for a new field of using theaflavins or its source, black tea, in the treatment of neurodegenerative diseases caused by oxidative stress. 相似文献
6.
Oxidative stress mediates the cell damage in several ailments including neurodegenerative conditions. Ocimum sanctum is widely used in Indian ayurvedic medications to cure various ailments. The present study was carried out to investigate the antioxidant activity and neuroprotective effects of hydroalcoholic extract of O. sanctum (OSE) on hydrogen peroxide (H 2O 2)-induced oxidative challenge in SH-SY5Y human neuronal cells. The extract exhibited strong antioxidant activity against DPPH, 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) radical and hydroxyl radicals with IC 50 values of 395 ± 16.2, 241 ± 11.5 and 188.6 ± 12.2 μg/ml respectively, which could be due to high amount of polyphenols and flavonoids. The observed data demonstrates 41.5 % cell survival with 100 μM H 2O 2 challenge for 24 h, which was restored to 73 % by pre-treatment with OSE for 2 h. It also decreased the lactate dehydrogenase leakage and preserved the cellular morphology. Similarly OSE inhibited lipid peroxidation, DNA damage, reactive oxygen species generation and depolarization of mitochondrial membrane. The extract restored superoxide dismutase and catalase enzyme/protein levels and further downregulated HSP-70 over-expression. These findings suggest that OSE ameliorates H 2O 2 induced neuronal damage via its antioxidant defence mechanism and might be used to treat oxidative stress mediated neuronal disorders. 相似文献
8.
To verify the antioxidative role of SelW in oxidant-induced chicken splenic lymphocyte, in this report, the influence of selenite supplementation and SelW gene silence on H 2O 2-mediated cell viability and cell apoptosis in cultured splenic lymphocyte derived from spleen of chicken were examined. The cultured cells were treated with sodium selenite and H 2O 2, or knocked down SelW with small interfering RNAs (siRNAs). The lymphocytes were examined for cell viability, cell apoptosis and mRNA expression levels of SelW and apoptosis-related genes (Bcl-2, Bax, Bak-1, caspase-3 and p53). The results show that the mRNA expression of SelW were effectively increased after treatment with sodium selenite, and H 2O 2-induced cell apoptosis was significantly decreased and cell viability was significantly increased. 20 μM H 2O 2 was found to induce cell apoptosis and decrease cell viability, which was alleviated obviously when cells were pretreated with sodium selenite before exposure to 20 μM H 2O 2. Meanwhile, H 2O 2 induced a significantly up-regulation of the Bax/Bcl-2 ratio, Bax, Bak-1, caspase-3 and p53 and down-regulation of Bcl-2 ( P < 0.05). When lymphocytes were pretreated with Se before treated with H 2O 2, the Bax/Bcl-2 ratio and mRNA expression of those genes were significantly decreased, and Bcl-2 was increased ( P < 0.05). SelW siRNA-transfected cells were more sensitive to the oxidative stress induced by treatment of H 2O 2 than control cells. Silencing of the lymphocyte SelW gene decreased their cell viability, and increased their apoptosis rate and susceptibility to H 2O 2. Silencing of SelW significantly up-regulated the Bax/Bcl-2 ratio, Bax, Bak-1, caspase-3 and p53 and down-regulated Bcl-2 ( P < 0.05). The present study demonstrates that SelW plays an important role in protection of splenic lymphocyte of birds from oxidative stress. 相似文献
9.
Astroglial cells are important actors in the defense of brain against oxidative stress injuries. Glial cells synthesize and release the octadecaneuropeptide ODN, a diazepam-binding inhibitor (DBI)-related peptide, which acts through its metabotropic receptor to protect neurons and astrocytes from oxidative stress-induced apoptosis. The purpose of the present study is to examine the contribution of the endogenous ODN in the protection of astrocytes and neurons from moderate oxidative stress. The administration of H 2O 2 (50 μM, 6 h) induced a moderate oxidative stress in cultured astrocytes, i.e., an increase in reactive oxygen species, malondialdehyde, and carbonyl group levels, but it had no effect on astrocyte death. Mass spectrometry and QPCR analysis revealed that 50 μM H 2O 2 increased ODN release and DBI mRNA levels. The inhibition of ODN release or pharmacological blockage of the effects of ODN revealed that in these conditions, 50 μM H 2O 2 induced the death of astrocytes. The transfection of astrocytes with DBI siRNA increased the vulnerability of cells to moderate stress. Finally, the addition of 1 nM ODN to culture media reversed cell death observed in DBI-deficient astrocytes. The treatment of neurons with media from 50 μM H 2O 2-stressed astrocytes significantly reduced the neuronal death induced by H 2O 2; this effect is greatly attenuated by the administration of an ODN metabotropic receptor antagonist. Overall, these results indicate that astrocytes produce authentic ODN, notably in a moderate oxidative stress situation, and this glio- and neuro-protective agent may form part of the brain defense mechanisms against oxidative stress injury. 相似文献
10.
Diabetic cardiomyopathy has been shown to promote hypertrophy, leading to heart failure. Recent studies have reported a correlation between diabetic cardiomyopathy and oxidative stress, suggesting that the accumulation of advanced glycation end products (AGEs) induces the production of reactive oxygen species (ROS). In a clinical setting, AGEs have been shown to increase the risk of cardiovascular disease; however, the relationship between AGEs and cardiac hypertrophy remains unclear. This study sought to identify the role of AGEs in cardiac hypertrophy by treating H9c2 cells with glyceraldehyde-derived AGEs (200 μg/ml) or H 2O 2 (50 μM) for 96 h. Our results demonstrate that AGEs significantly increased protein levels and cell size. These effects were effectively blocked with PD98059 (10 μM; MEK/ERK inhibitor) pretreatment, suggesting that AGEs caused cell hypertrophy via the MEK/ERK pathway. We then treated cells with AGEs and H 2O 2 for 0–120 min and employed the Odyssey infrared imaging system to detect MEK/ERK phosphorylation. Our results show that AGEs up-regulated MEK/ERK phosphorylation. However, this effect was blocked by NAC (5 mM; ROS inhibitor), indicating that AGEs regulate MEK/ERK phosphorylation via ROS. Our findings suggest that glyceraldehyde-derived AGEs are closely related to cardiac hypertrophy and further identify a molecular mechanism underlying the promotion of diabetic cardiomyopathy by AGEs. 相似文献
11.
Transplantation of neural-like cells is considered as a promising therapeutic strategy developed for neurodegenerative disease in particular for ischemic stroke. Since cell survival is a major concern following cell implantation, a number of studies have underlined the protective effects of preconditioning with hypoxia or hypoxia mimetic pharmacological agents such as deferoxamine (DFO), induced by activation of hypoxia inducible factor-1 (HIF-1) and its target genes. The present study has investigated the effects of DFO preconditioning on some factors involved in cell survival, angiogenesis, and neurogenesis of neural-like cells derived from human Wharton’s jelly mesenchymal stem cells (HWJ-MSCs) in presence of hydrogen peroxide (H 2O 2). HWJ-MSCs were differentiated toward neural-like cells for 14 days and neural cell markers were identified using immunocytochemistry. HWJ-MSC-derived neural-like cells were then treated with 100 µM DFO, as a known hypoxia mimetic agent for 48 h. mRNA and protein expression of HIF-1 target genes including brain-derived neurotrophic factors (BDNF) and vascular endothelial growth factor (VEGF) significantly increased using RT-PCR and Western blotting which were reversed by HIF-1α inhibitor, while, gene expression of Akt-1, Bcl-2, and Bax did not change significantly but pAkt-1 was up-regulated as compared to poor DFO group. However, addition of H 2O 2 to DFO-treated cells resulted in higher resistance to H 2O 2-induced cell death. Western blotting analysis also showed significant up-regulation of HIF-1α, BDNF, VEGF, and pAkt-1, and decrease of Bax/Bcl-2 ratio as compared to poor DFO. These results may suggest that DFO preconditioning of HWJ-MSC-derived neural-like cells improves their tolerance and therapeutic potential and might be considered as a valuable strategy to improve cell therapy. 相似文献
13.
Menadione (MD) is an effective cytotoxic drug able to produce intracellularly large amounts of superoxide anion. Quercetin (QC), a widely distributed bioflavonoid, can exert both antioxidant and pro-oxidant effects and is known to specifically inhibit cell proliferation and induce apoptosis in different cancer cell types. We have investigated the relation between delayed luminescence (DL) induced by UV-laser excitation and the effects of MD, hydrogen peroxide, and QC on apoptosis and cell cycle in human leukemia Jurkat T-cells. Treatments with 500 μM H 2O 2 and 250 μM MD for 20 min produced 66.0 ± 4.9 and 46.4 ± 8.6% apoptotic cell fractions, respectively. Long-term (24 h) pre-exposure to 5 μM, but not 0.5 μM QC enhanced apoptosis induced by MD, whereas short-term (1 h) pre-incubation with 10 μM QC offered 50% protection against H 2O 2-induced apoptosis, but potentiated apoptosis induced by MD. Since physiological levels of QC in the blood are normally less than 10 μM, these data can provide relevant information regarding the benefits of flavonoid-combined treatments of leukemia. All the three drugs exerted significant effects on DL. Our data are consistent with (1) the involvement of Complex I of the mitochondrial respiratory chain as an important source of delayed light emission on the 10 μs–10 ms scale, (2) the ability of superoxide anions to quench DL on the 100 μs–10 ms scale, probably via inhibition of reverse electron transfer at the Fe/S centers in Complex I, and (3) the relative insensitivity of DL to intracellular OH ? and H 2O 2 levels. 相似文献
15.
The present work was carried out to evaluate the antioxidant activity of hesperidin and to study its protective effect on H 2O 2 induced oxidative damage on pBR322 DNA and RBC cellular membrane. The in vitro assays were performed with different concentrations (2, 4, 6, 8, and 10 μg/ml, which were equivalent to 3.27, 6.55, 9.83, 13.10, and 16.38 μM) of hesperidin and the results clearly indicate that hesperidin at 10 μg/ml exhibited radical scavenging activity greater than that of standards like ascorbic acid and trolox. The protective effect of hesperidin on pBR322 DNA and RBC cellular membrane on treatment with different concentrations of H 2O 2 shows that hesperidin at 2.5 mM converts the open circular form (oc) of pBR322 DNA that is an indication of damage to super coiled (ccc) form and at 10 μg/ml it prevents membrane damage. Thus, our result proves hesperidin to be a valuable antioxidant that protects pBR322 DNA and RBC cellular membrane from free radical induced oxidative damage. 相似文献
16.
In Saccharomyces cerevisiae, the diffusion rate of hydrogen peroxide (H 2O 2) through the plasma membrane decreases during adaptation to H 2O 2 by means of a mechanism that is still unknown. Here, evidence is presented that during adaptation to H 2O 2 the anisotropy of the plasma membrane increases. Adaptation to H 2O 2 was studied at several times (15min up to 90min) by applying the steady-state H 2O 2 delivery model. For wild-type cells, the steady-state fluorescence anisotropy increased after 30min, or 60min, when using 2-(9-anthroyloxy) stearic acid (2-AS), or diphenylhexatriene (DPH) membrane probe, respectively. Moreover, a 40% decrease in plasma membrane permeability to H 2O 2 was observed at 15min with a concomitant two-fold increase in catalase activity. Disruption of the ergosterol pathway, by knocking out either ERG3 or ERG6, prevents the changes in anisotropy during H 2O 2 adaptation. H 2O 2 diffusion through the plasma membrane in S. cerevisiae cells is not mediated by aquaporins since the H 2O 2 permeability constant is not altered in the presence of the aquaporin inhibitor mercuric chloride. Altogether, these results indicate that the regulation of the plasma membrane permeability towards H 2O 2 is mediated by modulation of the biophysical properties of the plasma membrane. 相似文献
17.
Abscisic acid (ABA), a widely known phytohormone involved in the plant response to abiotic stress, plays a vital role in mitigating Cd2+ toxicity in herbaceous species. However, the role of ABA in ameliorating Cd2+ toxicity in woody species is largely unknown. In the present study, we investigated ABA restriction on Cd2+ uptake and the relevance to Cd2+ stress alleviation in Cd2+-hypersensitive Populus euphratica. ABA (5 μM) markedly improved cell viability and growth but reduced membrane permeability in CdCl2 (100 μM)-stressed P. euphratica cells. Moreover, ABA significantly increased the activity of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX), contributing to the scavenging of Cd2+-elicited H2O2 within P. euphratica cells during the period of CdCl2 exposure (100 μM, 24–72 h). ABA alleviation of Cd2+ toxicity was mainly the result of ABA restriction of Cd2+ uptake under Cd2+ stress. Steady-state and transient flux recordings showed that ABA inhibited Cd2+ entry into Cd2+-shocked (100 μM, 30 min) and short-term-stressed P. euphratica cells (100 μM, 24–72 h). Non-invasive micro-test technique data showed that H2O2 (3 mM) stimulated the Cd2+-elicited Cd2+ influx but that the plasma membrane (PM) Ca2+ channel inhibitor LaCl3 blocked it, suggesting that the Cd2+ influx was through PM Ca2+-permeable channels. These results suggested that ABA up-regulated antioxidant enzyme activity in Cd2+-stressed P. euphratica and that these enzymes scavenged the Cd2+-elicited H2O2 within cells. The entry of Cd2+ through the H2O2-mediated Ca2+-permeable channels was subsequently restricted; thus, Cd2+ buildup and toxicity were reduced in the Cd2+-hypersensitive species, P. euphratica. 相似文献
18.
Nitric oxide (NO) is a stress factor or a signal molecule involved in various plant physiological and developmental processes. In the present study, the generation of reactive oxygen species and the metabolism of proline due to different sodium nitroprusside (SNP, an NO donor) concentrations were investigated in callus from halophyte Nitraria tangutorum Bobr. Treatment with SNP led to significant increases of hydrogen peroxide (H 2O 2) content and cell viability but notable reductions in hydrogen radical level and lipid peroxidation degree, and superoxide onion (O 2 ?) content also enhanced in 100 μM SNP-treated calli. Using a chemical inhibitor for plasma membrane (PM) NADPH oxidase diphenylene iodonium (DPI), we found low O 2 ? generation in untreated and 25 μM SNP-treated calli, whereas in those treated with 100 μM SNP O 2 ? level exhibited a very little alteration, comparable to the absence of DPI. These suggest a high activity of PM NADPH oxidase in untreated calli. H 2O 2 scavenging enzymes (catalase, peroxidase [POD] and ascorbate peroxidase) and H 2O 2 forming enzymes (superoxide dismutase [SOD], cell wall-POD and diamine oxidase [DAO]) stimulated significantly in calli treated with different SNP concentrations while glutathione reductase activity decreased. In addition, a reduction in proline content was observed in SNP-treated calli. Moreover, different SNP concentrations stimulated proline dehydrogenase (PDH) and ornithine δ-aminotransferase but inhibited r-glutamyl kinase (GK). In conclusion, our results suggest that the increasing H 2O 2 generation was associated with the stimulation of SOD, cell wall-POD and DAO, and that the reduction of proline content might be the consequence of increased PDH activity and decreased GK activity in N. tangutorum Bobr. calli under SNP treatment. 相似文献
19.
It has been widely suggested that selenium (Se) deficiency play an important role in the pathophysiology of epilepsy. It has been reported that Se provides protection against the neuronal damage in patients and animals with epilepsy by restoring the antioxidant defense mechanism. The neuroprotective effects of topiramate (TPM) have been reported in several studies but the putative mechanism of action remains elusive. We investigated effects of Se and TPM in neuronal PC12 cell by evaluating Ca 2+ mobilization, lipid peroxidation and antioxidant levels. PC12 cells were divided into eight groups namely control, TPM, Se, H 2O 2, TPM + H 2O 2, Se + H 2O 2, Se + TPM and Se + TPM + H 2O 2. The toxic doses and times of H 2O 2, TPM and Se were determined by cell viability assay which is used to evaluate cell viability. Cells were incubated with 0.01 mM TPM for 5 h and 500 nM Se for 10 h. Then, the cells were exposed to 0.1 mM H 2O 2 for 10 h before analysis. The cells in all groups except control, TPM and Se were exposed to H 2O 2 for 15 min before analysis. Cytosolic Ca 2+ release and lipid peroxidation levels were higher in H 2O 2 group than in control, Se and TPM combination groups although their levels were decreased by incubation of Se and TPM combination. However, there is no difference on Ca 2+ release in TPM group. Glutathione peroxidase activity, reduced glutathione and vitamin C levels in the cells were lower in H 2O 2 group than in control, Se and TPM groups although their values were higher in the cells incubated with Se and TPM groups than in H 2O 2 groups. In conclusion, these results indicate that Se induced protective effects on oxidative stress in PC12 cells by modulating cytosolic Ca 2+ influx and antioxidant levels. TPM modulated also lipid peroxidation and glutathione and vitamin C concentrations in the cell system. 相似文献
20.
Oxidative stress and miRNAs have been confirmed to play an important role in neurological diseases. The study aimed to explore the underlying effect and mechanisms of miR-146a in H 2O 2-induced injury of PC12 cells. Here, PC12 cells were stimulated with 200 μM of H 2O 2 to construct oxidative injury model. Cell injury was evaluated on the basis of the changes in cell viability, migration, invasion, apoptosis, and DNA damage. Results revealed that miR-146a expression was up-regulated in H 2O 2-induced PC12 cells. Functional analysis showed that down-regulation of miR-146a alleviated H 2O 2-induced cytotoxicity in PC12 cells. Dual-luciferase reporter and western blot assay verified that MCL1 was a direct target gene of miR-146a. Moreover, anti-miR-146a-mediated suppression on cell cytotoxicity was abated following MCL1 knockdown in H 2O 2-induced PC12 cells. Furthermore, MCL1 activated JAK/STAT signaling pathway and MCL1 overexpression attenuated H 2O 2-induced cytotoxicity in PC12 cells by JAK/STAT signaling pathway. In conclusion, this study suggested that suppression of miR-146a abated H 2O 2-induced cytotoxicity in PC12 cells via regulating MCL1/JAK/STAT pathway. 相似文献
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