Displaying publications 221 - 240 of 297 in total

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  1. Neuroprotection of α-synuclein under acute and chronic rotenone and maneb treatment is abolished by its familial Parkinson's disease mutations A30P, A53T and E46K
    Choong CJ, Say YH
    Neurotoxicology, 2011 Dec;32(6):857-63.
    PMID: 21658409 DOI: 10.1016/j.neuro.2011.05.012
    α-Synuclein (α-Syn) plays a crucial role in the pathophysiology of Parkinson's disease (PD). α-Syn has been extensively studied in many neuronal cell-based PD models but has yielded mixed results. The objective of this study was to re-evaluate the dual cytotoxic/protective roles of α-Syn in dopaminergic SH-SY5Y cells. Stable SH-SY5Y cells overexpressing wild type or familial α-Syn mutants (A30P, E46K and A53T) were subjected to acute and chronic rotenone and maneb treatment. Compared with untransfected SH-SY5Y cells, wild type α-Syn attenuated rotenone and maneb-induced cell death along with an attenuation of toxin-induced mitochondrial membrane potential changes and Reactive Oxygen Species level, whereas the mutant α-Syn constructs exacerbated environmental toxins-induced cytotoxicity. After chronic treatment, wild type α-Syn but not the mutant variants was found to rescue cells from subsequent acute hydrogen peroxide insult. These results suggest that the fundamental property of wild type α-Syn may be protective, and such property may be lost by its familial PD mutations.
    Matched MeSH terms: Hydrogen Peroxide/toxicity
  2. Fulltext Effect of experimental treatment on GAPDH mRNA expression as a housekeeping gene in human diploid fibroblasts
    Zainuddin A, Chua KH, Abdul Rahim N, Makpol S
    BMC Mol. Biol., 2010;11:59.
    PMID: 20707929 DOI: 10.1186/1471-2199-11-59
    Several genes have been used as housekeeping genes and choosing an appropriate reference gene is important for accurate quantitative RNA expression in real time RT-PCR technique. The expression levels of reference genes should remain constant between the cells of different tissues and under different experimental conditions. The purpose of this study was to determine the effect of different experimental treatments on the expression of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) mRNA so that the reliability of GAPDH as reference gene for quantitative real time RT-PCR in human diploid fibroblasts (HDFs) can be validated. HDFs in 4 different treatment groups viz; young (passage 4), senescent (passage 30), H2O2-induced oxidative stress and gamma-tocotrienol (GTT)-treated groups were harvested for total RNA extraction. Total RNA concentration and purity were determined prior to GAPDH mRNA quantification. Standard curve of GAPDH expression in serial diluted total RNA, melting curve analysis and agarose gel electrophoresis were used to determine the reliability of GAPDH as reference gene.
    Matched MeSH terms: Hydrogen Peroxide/pharmacology
  3. Adjunctive use of superoxidized solution in chest wall necrotizing soft tissue infection
    Tata MD, Kwan KC, Abdul-Razak MR, Paramalingam S, Yeen WC
    Ann Thorac Surg, 2009 May;87(5):1613-4.
    PMID: 19379926 DOI: 10.1016/j.athoracsur.2008.10.019
    A 39-year-old Indian man presented with necrotizing soft tissue infection of his right forearm and previously undiagnosed diabetes mellitus. The infection progressively worsened to involve his right lateral chest wall despite multiple debridements and systemic antibiotics. His right arm was eventually disarticulated along with wide debridement of the surrounding tissue. Aggressive wound debridement, mechanical scrubbing, and irrigation were then initiated every 8 hours. A superoxidized solution was later introduced as a wound irrigant and dressing agent. The large defect was suitable for split-thickness skin grafting after 16 days of a strict wound management routine with the superoxidized solution.
    Matched MeSH terms: Hydrogen Peroxide/therapeutic use*
  4. Heat treatment effects on the characteristics and sonocatalytic performance of TiO2 in the degradation of organic dyes in aqueous solution
    Abdullah AZ, Ling PY
    J Hazard Mater, 2010 Jan 15;173(1-3):159-67.
    PMID: 19740600 DOI: 10.1016/j.jhazmat.2009.08.060
    The ambient sonocatalytic degradation of congo red, methyl orange, and methylene blue by titanium dioxide (TiO(2)) catalyst at initial concentrations between 10 and 50mg/L, catalyst loadings between 1.0 and 3.0mg/L and hydrogen peroxide (H(2)O(2)) concentrations up to 600 mg/L is reported. A 20 kHz ultrasonic processor at 50 W was used to accelerate the reaction. The catalysts were exposed to heat treatments between 400 and 1000 degrees C for up to 4h to induce phase change. Sonocatalysts with small amount of rutile phase showed better sonocatalytic activity but excessive rutile phase should be avoided. TiO(2) heated to 800 degrees C for 2h showed the highest sonocatalytic activity and the degradation of dyes was influenced by their chemical structures, chemical phases and characteristics of the catalysts. Congo red exhibited the highest degradation rate, attributed to multiple labile azo bonds to cause highest reactivity with the free radicals generated. An initial concentration of 10mg/L, 1.5 g/L of catalyst loading and 450 ppm of H(2)O(2) gave the best congo red removal efficiency of above 80% in 180 min. Rate coefficients for the sonocatalytic process was successfully established and the reused catalyst showed an activity drop by merely 10%.
    Matched MeSH terms: Hydrogen Peroxide/chemistry
  5. Is vitamin E toxic to neuron cells?
    Then SM, Mazlan M, Mat Top G, Wan Ngah WZ
    Cell Mol Neurobiol, 2009 Jun;29(4):485-96.
    PMID: 19172392 DOI: 10.1007/s10571-008-9340-8
    Besides acting as potent free radical scavengers, tocopherols and tocotrienols have been known to have non-antioxidant properties such as the involvement of alpha-tocopherol (alphaT) in PKC pathway and the anti-cancer properties of gamma-tocotrienol (gammaT3). This study aims to elucidate whether protective effects shown by alphaT and gammaT3 in H(2)O(2)-induced neuron cultures have anti-apoptotic or pro-apoptotic tendency toward the initiation of neuronal apoptosis. H(2)O(2) is used to induce apoptosis in primary cerebellar neuron cultures which is attenuated by pretreatment of alphaT or gammaT3 at concentrations < or =10 microM. Similar to our previous work, gammaT3 was found to be neurotoxic at concentrations > or =100 microM, whereas alphaT showed no neurotoxicity. Cellular uptake of gammaT3 was higher than that of alphaT. Treating cells simultaneously with either gammaT3 or alphaT and with then H(2)O(2) led to higher expression of Bax and Bcl-2 than in neurons exposed to H(2)O(2) alone. Analysis of Bcl-2/Bax ratio as 'survival index' showed that both pretreatment of gammaT3 and alphaT followed by H(2)O(2) increase the 'survival index' of Bcl-2/Bax ratio compared to H(2)O(2)-treated cells, while treatment of gammaT3 alone decrease the ratio compared to unchanged Bcl2/Bax ratio of similar treatment with alphaT alone. Similar treatment of gammaT3 decreased p53 expression and activates p38 MAPK phosphorylation, whereas alphaT did not alter its expression compared to H(2)O(2)-treated cells. Treating neurons with only gammaT3 or alphaT increased the expression of Bax, Bcl-2, p53, and p38 MAPK compared to control with gammaT3 exerting stronger expression for proteins involved than alphaT. In conclusion, low doses of gammaT3 and alphaT confer neuroprotection to H(2)O(2)-treated neurons via their antioxidant mechanism but gammaT3 has stronger pro-apoptosis tendency than alphaT by activating molecules involved in the neuronal apoptotic pathway in the absence of H(2)O(2).
    Matched MeSH terms: Hydrogen Peroxide/pharmacology
  6. Chlorella vulgaris modulates hydrogen peroxide-induced DNA damage and telomere shortening of human fibroblasts derived from different aged individuals
    Makpol S, Yaacob N, Zainuddin A, Yusof YA, Ngah WZ
    Afr J Tradit Complement Altern Med, 2009 Jul 03;6(4):560-72.
    PMID: 20606778
    The objective of this study was to investigate the modulatory effect of Chlorella vulgaris on cultured fibroblast cells derived from young and old aged individuals focusing on DNA damage, telomere length and telomerase activity. Dose-response test of the algal extract on cells in both age groups revealed that optimum viability was observed at a concentration of 50 microg/ml. Results obtained showed that Chlorella vulgaris exhibited protective effects against H(2)O(2)-induced oxidative stress as shown by the reduction in damaged DNA caused by H(2)O(2) treatment (p<0.05) in Chlorella vulgaris pre- and post-treated groups (p<0.05). Pre-treatment of Chlorella vulgaris resulted in a significant decrease in DNA damage suggesting a bioprotective effect against free radical attacks. A decline in DNA damage was observed in post-treated cells which proves Chlorella vulgaris to present bioremediative properties. In cells induced with oxidative stress, telomere length decreased significantly coupled with a concomitant decline of telomerase activity (p<0.05). However, these reductions were prevented with prior and post treatment of Chlorella vulgaris. Therefore, we concluded that Chlorella vulgaris exhibited bioprotective effects especially in cells obtained from young donor but were more bioremediative for cells obtained from old donor as indicated by DNA damage, telomere shortening and reduction in telomerase activity.
    Matched MeSH terms: Hydrogen Peroxide/pharmacology*
  7. Enzyme-linked amperometric electrochemical genosensor assay for the detection of PCR amplicons on a streptavidin-treated screen-printed carbon electrode
    Yean CY, Kamarudin B, Ozkan DA, Yin LS, Lalitha P, Ismail A, et al.
    Anal Chem, 2008 Apr 15;80(8):2774-9.
    PMID: 18311943 DOI: 10.1021/ac702333x
    A general purpose enzyme-based amperometric electrochemical genosensor assay was developed wherein polymerase chain reaction (PCR) amplicons labeled with both biotin and fluorescein were detected with peroxidase-conjugated antifluorescein antibody on a screen-printed carbon electrode (SPCE). As a proof of principle, the response selectivity of the genosensor was evaluated using PCR amplicons derived from lolB gene of Vibrio cholerae. Factors affecting immobilization, hybridization, and nonspecific binding were optimized to maximize sensitivity and reduce assay time. On the basis of the background amperometry signals obtained from nonspecific organisms and positive signals obtained from known V. cholerae, a threshold point of 4.20 microA signal was determined as positive. Under the optimum conditions, the limit of detection (LOD) of the assay was 10 CFU/mL of V. cholerae. The overall precision of this assay was good, with the coefficient of variation (CV) being 3.7% using SPCE and intermittent pulse amperometry (IPA) as an electrochemical technique. The assay is sensitive, safe, and cost-effective when compared to conventional agarose gel electrophoresis, real-time PCR, and other enzyme-linked assays for the detection of PCR amplicons. Furthermore, the use of a hand-held portable reader makes it suitable for use in the field.
    Matched MeSH terms: Hydrogen Peroxide/chemistry
  8. Stacked films immobilization of MBTH in nafion/sol-gel silicate and horseradish peroxidase in chitosan for the determination of phenolic compounds
    Abdullah J, Ahmad M, Heng LY, Karuppiah N, Sidek H
    Anal Bioanal Chem, 2006 Nov;386(5):1285-92.
    PMID: 17031625
    The stacked-film immobilization of 3-methyl-2-benzothiazolinone hydrazone (MBTH) in hybrid nafion/sol-gel silicate film and horseradish peroxidase (HRP) in chitosan, performed in order to allow the determination of phenolic compounds, was investigated via an optical method. The stacked films were deposited onto a microscope glass slide by a spin-coating technique. The quinone or free radical product formed by the enzymatic reactions of phenolic compounds interacts with MBTH to form azo-dye products, which can be measured spectrophotometrically at a wavelength of 500 nm. The color intensity of the product was found to increase in proportion to the phenolic concentration after 5 min of exposure. The response of the biosensor was linear over concentration ranges of 0.025-0.500, 0.010-0.070 and 0.050-0.300 mM for guaiacol, resorcinol and o-cresol, respectively, and gave detection limits of 0.010, 0.005 and 0.012 mM. The sensor exhibited good sensitivity and stability for at least two months.
    Matched MeSH terms: Hydrogen Peroxide/chemistry
  9. Fulltext Prospective role of mitochondrial apoptotic pathway in mediating GMG-ITC to reduce cytotoxicity in H2O2-induced oxidative stress in differentiated SH-SY5Y cells
    Jaafaru MS, Nordin N, Rosli R, Shaari K, Bako HY, Noor NM, et al.
    Biomed Pharmacother, 2019 Nov;119:109445.
    PMID: 31541852 DOI: 10.1016/j.biopha.2019.109445
    The antioxidant and neuroprotective activity of Glucomoringin isothiocyanate (GMG-ITC) have been reported in in vivo and in vitro models of neurodegenerative diseases. However, its neuroprotective role via mitochondrial-dependent pathway in a noxious environment remains unknown. The main objective of the present study was to unveil the mitochondrial apoptotic genes' profile and prospectively link with neuroprotective activity of GMG-ITC through its ROS scavenging. The results showed that pre-treatment of differentiated SH-SY5Y cells with 1.25 μg/mL purified isolated GMG-ITC, significantly reduced reactive oxygen species (ROS) production level, compared to H2O2 control group, as evidenced by flow cytometry-based evaluation of ROS generation. Presence of GMG-ITC prior to development of oxidative stress condition, downregulated the expression of cyt-c, p53, Apaf-1, Bax, CASP3, CASP8 and CASP9 genes with concurrent upregulation of Bcl-2 gene in mitochondrial apoptotic signalling pathway. Protein Multiplex revealed significant decreased in cyt-c, p53, Apaf-1, Bax, CASP8 and CASP9 due to GMG-ITC pre-treatment in oxidative stress condition. The present findings speculated that pre-treatment with GMG-ITC may alleviate oxidative stress condition in neuronal cells by reducing ROS production level and protect the cells against apoptosis via neurodegenerative disease potential pathways.
    Matched MeSH terms: Hydrogen Peroxide/toxicity*
  10. Proteomic analysis reveals that treatment with tocotrienols reverses the effect of H₂O₂ exposure on peroxiredoxin expression in human lymphocytes from young and old individuals
    Dahlan HM, Karsani SA, Rahman MA, Hamid NA, Top AG, Ngah WZ
    J Nutr Biochem, 2012 Jul;23(7):741-51.
    PMID: 21840697 DOI: 10.1016/j.jnutbio.2011.03.018
    Vitamin E has been suggested to modulate age-associated changes by altering the redox balance resulting in altered gene and/or protein expression. Here we have utilized proteomics to determine whether such regulation in protein expression occurs in human lymphocytes from two different age groups stressed with H₂O₂ and then treated with vitamin E in the form of tocotrienol-rich fraction (TRF). In this study, lymphocytes obtained from young (30-49 years old) and old (>50 years old) volunteers were first challenged with 1 mM H₂O₂. They were then treated by exposure to 50, 100 and 200 μg/ml TRF. Two-dimensional gel electrophoresis followed by MALDI-TOF/TOF (matrix-assisted laser desorption/ionization time-of-flight/time-of-flight) tandem mass spectrometry was then performed on whole-cell protein extracts to identify proteins that have changed in expression. A total of 24 proteins were found to be affected by H₂O₂ and/or TRF treatment. These included proteins that were related to metabolism, antioxidants, structural proteins, protein degradation and signal transduction. Of particular interest was the regulation of a number of proteins involved in stress response--peroxiredoxin-2, peroxiredoxin-3 and peroxiredoxin-6-all of which were shown to be down-regulated with H₂O₂ exposure. The effect was reversed following TRF treatment. The expression of peroxiredoxin-2 and peroxiredoxin-6 was confirmed by quantitative reverse transcriptase polymerase chain reaction. These results suggested that TRF directly influenced the expression dynamics of the peroxiredoxin-2, thus improving the cells ability to resist damage caused by oxidative stress.
    Matched MeSH terms: Hydrogen Peroxide/metabolism*
  11. Role of Bacopa monnieri in the temporal regulation of oxidative stress in clock mutant (cryb) of Drosophila melanogaster
    Subramanian P, Prasanna V, Jayapalan JJ, Abdul Rahman PS, Hashim OH
    J Insect Physiol, 2014 Jun;65:37-44.
    PMID: 24780191 DOI: 10.1016/j.jinsphys.2014.04.005
    Accruing evidences imply that circadian organization of biochemical, endocrinological, cellular and physiological processes contribute to wellness of organisms and in the development of pathologies such as malignancy, sleep and endocrine disorders. Oxidative stress is known to mediate a number of diseases and it is notable to comprehend the orchestration of circadian clock of a model organism of circadian biology, Drosophila melanogaster, under oxidative stress. We investigated the nexus between circadian clock and oxidative stress susceptibility by exposing D. melanogaster to hydrogen peroxide (H2O2) or rotenone; the reversibility of rhythms following exposure to Bacopa monnieri extract (ayurvedic medicine rich in antioxidants) was also investigated. Abolishment of 24h rhythms in physiological response (negative geotaxis), oxidative stress markers (protein carbonyl and thiobarbituric acid reactive substances) and antioxidants (superoxide dismutase, catalase, glutathione-S-transferase and reduced glutathione) were observed under oxidative stress. Furthermore, abolishment of per mRNA rhythm in H2O2 treated wild type flies and augmented susceptibility to oxidative stress in clock mutant (cry(b)) flies connotes the role of circadian clock in reactive oxygen species (ROS) homeostasis. Significant reversibility of rhythms was noted following B. monnieri treatment in wild type flies than cry(b) flies. Our experimental approach revealed a relationship involving oxidative stress and circadian clock in fruit fly and the utility of Drosophila model in screening putative antioxidative phytomedicines prior to their use in mammalian systems.
    Matched MeSH terms: Hydrogen Peroxide/metabolism
  12. The influence of hydrogen peroxide on the growth, development and quality of wax apple (Syzygium samarangense, [Blume] Merrill & L.M. Perry var. jambu madu) fruits
    Khandaker MM, Boyce AN, Osman N
    Plant Physiol Biochem, 2012 Apr;53:101-10.
    PMID: 22349652 DOI: 10.1016/j.plaphy.2012.01.016
    The present study represents the first report of the effect of hydrogen peroxide (H(2)O(2)) on the growth, development and quality of the wax apple fruit, a widely cultivated fruit tree in South East Asia. The wax apple trees were spray treated with 0, 5, 20 and 50 mM H(2)O(2) under field conditions. Photosynthetic rates, stomatal conductance, transpiration, chlorophyll and dry matter content of the leaves and total soluble solids and total sugar content of the fruits of wax apple (Syzygium samarangense, var. jambu madu) were significantly increased after treatment with 5 mM H(2)O(2). The application of 20 mM H(2)O(2) significantly reduced bud drop and enhanced fruit growth, resulting in larger fruit size, increased fruit set, fruit number, fruit biomass and yield compared to the control. In addition, the endogenous level of H(2)O(2) in wax apple leaves increased significantly with H(2)O(2) treatments. With regard to fruit quality, 20 mM H(2)O(2) treatment increased the K(+), anthocyanin and carotene contents of the fruits by 65%, 67%, and 41%, respectively. In addition, higher flavonoid, phenol and soluble protein content, sucrose phosphate synthase (SPS), phenylalanine ammonia lyase (PAL) and antioxidant activities were recorded in the treated fruits. There was a positive correlation between peel colour (hue) and TSS, between net photosynthesis and SPS activity and between phenol and flavonoid content with antioxidant activity in H(2)O(2)-treated fruits. It is concluded that spraying with 5 and 20 mM H(2)O(2) once a week produced better fruit growth, maximising the yield and quality of wax apple fruits under field conditions.
    Matched MeSH terms: Hydrogen Peroxide/pharmacology*
  13. Upregulation of catalase and downregulation of glutathione peroxidase activity in the kidney precede the development of hypertension in pre-hypertensive SHR
    Sundaram A, Siew Keah L, Sirajudeen KN, Singh HJ
    Hypertens Res, 2013 Mar;36(3):213-8.
    PMID: 23096233 DOI: 10.1038/hr.2012.163
    Although oxidative stress has been implicated in the pathogenesis of hypertension in spontaneously hypertensive rats (SHRs), there is little information on the levels of primary antioxidant enzymes status (AOEs) in pre-hypertensive SHR. This study therefore determined the activities of primary AOEs and their mRNA levels, levels of hydrogen peroxide (H2O2), malondialdehyde (MDA) and total antioxidant status (TAS) in whole kidneys of SHR and age-matched Wistar-Kyoto (WKY) rats aged between 2 and 16 weeks. Compared with age-matched WKY rats, catalase (CAT) activity was significantly higher from the age of 2 weeks (P<0.001) and glutathione peroxide (GPx) activity was lower from the age of 3 weeks (P<0.001) in SHR. CAT mRNA levels were significantly higher in SHR aged 2, 4, 6 and 12 weeks. GPx mRNA levels were significantly lower in SHR at 8 and 12 weeks. Superoxide dismutase activity or its mRNA levels were not different between the two strains. H2O2 levels were significantly lower in SHR from the age of 8 weeks (P<0.01). TAS was significantly higher in SHR from the age of 3 weeks (P<0.05). MDA levels were only significantly higher at 16 weeks of age in the SHR (P<0.05). The data suggest that altered renal CAT and GPx mRNA expression and activity precede the development of hypertension in SHR. The raised CAT activity perhaps contributes to the higher TAS and lower H2O2 levels in SHR. In view of these findings, the precise role of oxidative stress in the pathogenesis of hypertension in SHR needs to be investigated further.
    Matched MeSH terms: Hydrogen Peroxide/metabolism
  14. Comparative assessment of urinary oxidative indices in breast and colorectal cancer patients
    Chandramathi S, Suresh K, Anita ZB, Kuppusamy UR
    J Cancer Res Clin Oncol, 2009 Feb;135(2):319-23.
    PMID: 18758816 DOI: 10.1007/s00432-008-0462-7
    PURPOSE: This study aimed to use non-invasive methods to assess and compare the levels of oxidative indices and non-enzymatic antioxidants in breast and colorectal cancer (CRC) patients. Various studies have reported on lipid peroxidation, hydrogen peroxide (H(2)O(2)) and ferric-reducing antioxidant power (FRAP) levels in the serum of cancer patients but this is the first report that highlights the significance of urinary-advanced oxidative protein product (AOPP) in cancer patients.
    METHODS: The levels of advanced oxidative protein product (AOPP), hydrogen peroxide (H(2)O(2)), malondialdehyde (MDA) which is a marker for lipid peroxidation and ferric-reducing antioxidant power (FRAP) were measured in urine samples of breast (n = 101) and colorectal cancer (n = 49) patients attending the Oncology Clinic, University Malaya Medical Centre, Kuala Lumpur and were compared with 95 age-matched healthy individuals.
    RESULTS: AOPP, H(2)O(2) and MDA levels in the urine were significantly higher in the CRC patients compared to the control subjects and breast cancer patients. In breast cancer patients, only AOPP level was elevated. FRAP level did not differ between breast and colorectal cancer patients but the levels were significantly lower compared to control subjects.
    CONCLUSION: Urinary oxidative indices such as AOPP, H(2)O(2), and MDA as well as FRAP could serve as useful non-invasive oxidative stress markers in colorectal cancer but only AOPP serves as a useful urinary oxidative biomarker in breast cancer.
    Study site: Oncology clinic, University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia
    Matched MeSH terms: Hydrogen Peroxide/urine*
  15. Molecular mechanism of cell death induced by king cobra (Ophiophagus hannah) venom l-amino acid oxidase
    Fung SY, Lee ML, Tan NH
    Toxicon, 2015 Mar;96:38-45.
    PMID: 25615711 DOI: 10.1016/j.toxicon.2015.01.012
    Snake venom LAAOs have been reported to exhibit a wide range of pharmacological activities, including cytotoxic, edema-inducing, platelet aggregation-inducing/platelet aggregation-inhibiting, bactericidal and antiviral activities. A heat-stable form of l-amino acid oxidase isolated from king cobra (Ophiophagus hannah) venom (OH-LAAO) has been shown to exhibit very potent cytotoxicity against human tumorigenic cells but not in their non-tumorigenic counterparts, and the cytotoxicity was due to the apoptosis-inducing effect of the enzyme. In this work, the molecular mechanism of cell death induced by OH-LAAO was investigated. The enzyme exerts its apoptosis-inducing effect presumably via both intrinsic and extrinsic pathways as suggested by the increase in caspase-8 and -9 activities. Oligonucleotide microarray analysis showed that the expression of a total of 178 genes was significantly altered as a result of oxidative stress induced by the hydrogen peroxide generated by the enzyme. Of the 178 genes, at least 27 genes are involved in apoptosis and cell death. These alterations of gene expression was presumably caused by the direct cytotoxic effect of H2O2 generated during the enzymatic reaction, as well as the non-specific oxidative modifications of signaling molecules that eventually lead to apoptosis and cell death. The very substantial up-regulation of cytochrome P450 genes may also contribute to the potent cytotoxic action of OH-LAAO by producing excessive reactive oxygen species (ROS). In conclusion, the potent apoptosis inducing activity of OH-LAAO was likely due to the direct cytotoxic effect of H2O2 generated during the enzymatic reaction, as well as the non-specific oxidation of signalling molecules.
    Matched MeSH terms: Hydrogen Peroxide/metabolism*
  16. Fulltext Impaired redox environment modulates cardiogenic and ion-channel gene expression in cardiac-resident and non-resident mesenchymal stem cells
    Subramani B, Subbannagounder S, Ramanathanpullai C, Palanivel S, Ramasamy R
    Exp Biol Med (Maywood), 2017 03;242(6):645-656.
    PMID: 28092181 DOI: 10.1177/1535370216688568
    Redox homeostasis plays a crucial role in the regulation of self-renewal and differentiation of stem cells. However, the behavioral actions of mesenchymal stem cells in redox imbalance state remain elusive. In the present study, the effect of redox imbalance that was induced by either hydrogen peroxide (H2O2) or ascorbic acid on human cardiac-resident (hC-MSCs) and non-resident (umbilical cord) mesenchymal stem cells (hUC-MSCs) was evaluated. Both cells were sensitive and responsive when exposed to either H2O2 or ascorbic acid at a concentration of 400 µmol/L. Ascorbic acid pre-treated cells remarkably ameliorated the reactive oxygen species level when treated with H2O2. The endogenous antioxidative enzyme gene (Sod1, Sod2, TRXR1 and Gpx1) expressions were escalated in both MSCs in response to reactive oxygen species elevation. In contrast, ascorbic acid pre-treated hUC-MSCs attenuated considerable anti-oxidative gene (TRXR1 and Gpx1) expressions, but not the hC-MSCs. Similarly, the cardiogenic gene (Nkx 2.5, Gata4, Mlc2a and β-MHC) and ion-channel gene ( IKDR, IKCa, Ito and INa.TTX) expressions were significantly increased in both MSCs on the oxidative state. On the contrary, reduced environment could not alter the ion-channel gene expression and negatively regulated the cardiogenic gene expressions except for troponin-1 in both cells. In conclusion, redox imbalance potently alters the cardiac-resident and non-resident MSCs stemness, cardiogenic, and ion-channel gene expressions. In comparison with cardiac-resident MSC, non-resident umbilical cord-MSC has great potential to tolerate the redox imbalance and positively respond to cardiac regeneration. Impact statement Human mesenchymal stem cells (h-MSCs) are highly promising candidates for tissue repair in cardiovascular diseases. However, the retention of cells in the infarcted area has been a major challenge due to its poor viability and/or low survival rate after transplantation. The regenerative potential of mesenchymal stem cells (MSCs) repudiate and enter into premature senescence via oxidative stress. Thus, various strategies have been attempted to improve the MSC survival in 'toxic' conditions. Similarly, we investigated the response of cardiac resident MSC (hC-MSCs) and non-resident MSCs against the oxidative stress induced by H2O2. Supplementation of ascorbic acid (AA) into MSCs culture profoundly rescued the stem cells from oxidative stress induced by H2O2. Our data showed that the pre-treatment of AA is able to inhibit the cell death and thus preserving the viability and differentiation potential of MSCs.
    Matched MeSH terms: Hydrogen Peroxide/pharmacology
  17. Fulltext Pleurotus giganteus (Berk. Karun & Hyde), the giant oyster mushroom inhibits NO production in LPS/H2O2 stimulated RAW 264.7 cells via STAT 3 and COX-2 pathways
    Baskaran A, Chua KH, Sabaratnam V, Ravishankar Ram M, Kuppusamy UR
    BMC Complement Altern Med, 2017 Jan 13;17(1):40.
    PMID: 28086773 DOI: 10.1186/s12906-016-1546-6
    Pleurotus giganteus (Berk. Karunarathna and K.D. Hyde), has been used as a culinary mushroom and is known to have medicinal properties but its potential as an anti-inflammatory agent to mitigate inflammation triggered diseases is untapped. In this study, the molecular mechanism underlying the protective effect of ethanol extract of P. giganteus (EPG) against lipopolysaccharide (LPS) and combination of LPS and hydrogen peroxide (H2O2)-induced inflammation on RAW 264.7 macrophages was investigated.
    Matched MeSH terms: Hydrogen Peroxide/toxicity
  18. Lutein improves cell viability and reduces Alu RNA accumulation in hydrogen peroxide challenged retinal pigment epithelial cells
    Chong YS, Mai CW, Leong CO, Wong LC
    Cutan Ocul Toxicol, 2018 Mar;37(1):52-60.
    PMID: 28554225 DOI: 10.1080/15569527.2017.1335748
    PURPOSE: Dysfunction of the microRNA (miRNA)-processing enzyme DICER1 and Alu RNA accumulation are linked to the pathogenesis of age-related macular degeneration (AMD). This study determined the optimal dose of lutein (LUT) and zeaxanthin (ZEA) to protect human retinal pigment epithelium (RPE) cells against hydrogen peroxide (H2O2). The effect of the optimal dose of LUT and ZEA as DICER1 and Alu RNA modulators in cultured human RPE cells challenged with H2O2 was investigated.

    MATERIALS AND METHODS: ARPE-19 cells were pre-treated with LUT, ZEA, or both for 24 h before 200 μM H2O2 challenge. Cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. DICER1 and Alu RNA were quantified by western blotting and real-time polymerase chain reaction, respectively.

    RESULTS: H2O2 increased cell Alu RNA expression and decreased cell viability of ARPE-19, but had no significant impact on the DICER1 protein level. LUT, alone and in combination with ZEA pre-treatment, prior to H2O2 challenge significantly improved cell viability of ARPE-19 and reduced the level of Alu RNA compared to the negative control.

    CONCLUSIONS: These results support the use of LUT alone, and in combination with ZEA, in AMD prevention and treatment. This study is also the first to report LUT modulating effects on Alu RNA.

    Matched MeSH terms: Hydrogen Peroxide/toxicity*
  19. Fulltext Oxidative stress-induced chromosome breaks within the ABL gene: a model for chromosome rearrangement in nasopharyngeal carcinoma
    Tan SN, Sim SP, Khoo AS
    Hum Genomics, 2018 06 18;12(1):29.
    PMID: 29914565 DOI: 10.1186/s40246-018-0160-8
    BACKGROUND: The mechanism underlying chromosome rearrangement in nasopharyngeal carcinoma (NPC) remains elusive. It is known that most of the aetiological factors of NPC trigger oxidative stress. Oxidative stress is a potent apoptotic inducer. During apoptosis, chromatin cleavage and DNA fragmentation occur. However, cells may undergo DNA repair and survive apoptosis. Non-homologous end joining (NHEJ) pathway has been known as the primary DNA repair system in human cells. The NHEJ process may repair DNA ends without any homology, although region of microhomology (a few nucleotides) is usually utilised by this DNA repair system. Cells that evade apoptosis via erroneous DNA repair may carry chromosomal aberration. Apoptotic nuclease was found to be associated with nuclear matrix during apoptosis. Matrix association region/scaffold attachment region (MAR/SAR) is the binding site of the chromosomal DNA loop structure to the nuclear matrix. When apoptotic nuclease is associated with nuclear matrix during apoptosis, it potentially cleaves at MAR/SAR. Cells that survive apoptosis via compromised DNA repair may carry chromosome rearrangement contributing to NPC tumourigenesis. The Abelson murine leukaemia (ABL) gene at 9q34 was targeted in this study as 9q34 is a common region of loss in NPC. This study aimed to identify the chromosome breakages and/or rearrangements in the ABL gene in cells undergoing oxidative stress-induced apoptosis.

    RESULTS: In the present study, in silico prediction of MAR/SAR was performed in the ABL gene. More than 80% of the predicted MAR/SAR sites are closely associated with previously reported patient breakpoint cluster regions (BCR). By using inverse polymerase chain reaction (IPCR), we demonstrated that hydrogen peroxide (H2O2)-induced apoptosis in normal nasopharyngeal epithelial and NPC cells led to chromosomal breakages within the ABL BCR that contains a MAR/SAR. Intriguingly, we detected two translocations in H2O2-treated cells. Region of microhomology was found at the translocation junctions. This observation is consistent with the operation of microhomology-mediated NHEJ.

    CONCLUSIONS: Our findings suggested that oxidative stress-induced apoptosis may participate in chromosome rearrangements of NPC. A revised model for oxidative stress-induced apoptosis mediating chromosome rearrangement in NPC is proposed.

    Matched MeSH terms: Hydrogen Peroxide/chemistry
  20. Attenuation of oxidative stress induced mitochondrial dysfunction and cytotoxicity in fibroblast cells by sulfated polysaccharide from Padina gymnospora
    Vasantharaja R, Stanley Abraham L, Gopinath V, Hariharan D, Smita KM
    Int J Biol Macromol, 2019 Mar 01;124:50-59.
    PMID: 30445094 DOI: 10.1016/j.ijbiomac.2018.11.104
    In this present study, isolation, characterization and protective effect of sulfated polysaccharide (SP) isolated from the brown algae Padina gymnospora was investigated. SP was isolated and characterized through FT-IR, 1H NMR, TGA, GC-MS and CHN analysis. The molecular weight of SP was found to be 16 kDa. The isolated SP contains 29.4 ± 0.35% of sulfate, 27 ± 0.11% of fucose, 0.05 ± 0.12% of protein, respectively. Furthermore, SP exhibits its excellent radical scavenging effects were evaluated by DPPH, ABTS radical scavenging and reducing power assays. Moreover, pretreatment with SP significantly mitigates H2O2 induced cytotoxicity in L-929 cells in a dose dependent manner. Furthermore, SP pretreatment ameliorates oxidative stress induced apoptosis and DNA damage, alleviates the generation of intracellular reactive oxygen species (ROS) and restores mitochondrial membrane potential (MMP) in L-929 cells through its antioxidant potential. Together, these results suggest that SP can be exploited as a natural antioxidant in the food and pharmaceutical industries.
    Matched MeSH terms: Hydrogen Peroxide/chemistry
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