scholarly journals Zinc Protects Oxidative Stress-Induced RPE Death by Reducing Mitochondrial Damage and Preventing Lysosome Rupture

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Dinusha Rajapakse ◽  
Tim Curtis ◽  
Mei Chen ◽  
Heping Xu
Keyword(s):  
Oxidative Stress ◽  
Zinc Deficiency ◽  
Cathepsin B ◽  
Zinc Supplementation ◽  
Culture Conditions ◽  
Ros Production ◽  
Rpe Cells ◽  
Serum Free ◽  
Normal Culture ◽  
Atp Production

Zinc deficiency is known to increase the risk of the development of age-related macular degeneration (AMD), although the underlying mechanism remains poorly defined. In this study, we investigated the effect of zinc on retinal pigment epithelium (RPE) survival and function under oxidative conditions. Zinc level was 5.4 μM in normal culture conditions (DMEM/F12 with 10% FCS) and 1.5 μM in serum-free medium (DMEM/F12). Under serum-free culture conditions, the treatment of RPE cells with oxidized photoreceptor outer segment (oxPOS) significantly increased intracellular ROS production, reduced ATP production, and promoted RPE death compared to oxPOS-treated RPE under normal culture condition. Serum deprivation also reduced RPE phagocytosis of oxPOS and exacerbated oxidative insult-induced cathepsin B release from lysosome, an indicator of lysosome rupture. The addition of zinc in the serum-free culture system dose dependently reduced ROS production, recovered ATP production, and reduced oxidative stress- (oxPOS- or 4-HNE) induced cell death. Zinc supplementation also reduced oxidative stress-mediated cathepsin B release in RPE cells. Our results suggest that zinc deficiency sensitizes RPE cells to oxidative damage, and zinc supplementation protects RPE cells from oxidative stress-induced death by improving mitochondrial function and preventing lysosome rupture.

scholarly journals Molecular Mechanisms of Zinc as a Pro-Antioxidant Mediator: Clinical Therapeutic Implications

Antioxidants ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 164 ◽  
Author(s):  
Ananda S. Prasad ◽  
Bin Bao
Keyword(s):  
Oxidative Stress ◽  
Immune Response ◽  
Human Health ◽  
Zinc Deficiency ◽  
Molecular Mechanisms ◽  
Zinc Supplementation ◽  
Experimental Studies ◽  
The Body ◽  
Ros Production ◽  
Stress Agent

The essentiality of zinc as a trace mineral in human health has been recognized for over five decades. Zinc deficiency, caused by diet, genetic defects, or diseases, can cause growth retardation, delayed sexual maturation, depressed immune response, and abnormal cognitive functions in humans. Zinc supplementation in zinc-deficient individuals can overcome or attenuate these abnormalities, suggesting zinc is an essential micro-nutrient in the body. A large number of in vitro and in vivo experimental studies indicate that zinc deficiency also causes apoptosis, cellular dysfunction, deoxyribonucleic acid (DNA) damage, and depressed immune response. Oxidative stress, due to the imbalance of reactive oxygen species (ROS) production and detoxification in the anti-oxidant defense system of the body, along with subsequent chronic inflammation, is believed to be associated with many chronic degenerative diseases such as diabetes, heart diseases, cancers, alcohol-related disease, macular degenerative disease, and neuro-pathogenesis. A large number of experimental studies including cell culture, animal, and human clinical studies have provided supportive evidence showing that zinc acts as an anti-oxidative stress agent by inhibition of oxidation of macro-molecules such as (DNA)/ribonucleic acid (RNA) and proteins as well as inhibition of inflammatory response, eventually resulting in the down-regulation of (ROS) production and the improvement of human health. In this article, we will discuss the molecular mechanisms of zinc as an anti-oxidative stress agent or mediator in the body. We will also discuss the applications of zinc supplementation as an anti-oxidative stress agent or mediator in human health and disease.

scholarly journals Oxidative Stress is the Principal Contributor to Inflammasome Activation in Retinal Pigment Epithelium Cells with Defunct Proteasomes and Autophagy

2018 ◽  
Vol 49 (1) ◽  
pp. 359-367 ◽  
Author(s):  
Niina Piippo ◽  
Eveliina Korhonen ◽  
Maria Hytti ◽  
Kati Kinnunen ◽  
Kai Kaarniranta ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nlrp3 Inflammasome ◽  
Cathepsin B ◽  
Retinal Pigment ◽  
Inflammasome Activation ◽  
Bafilomycin A1 ◽  
Potassium Efflux ◽  
Rpe Cells ◽  
Activation Mechanisms ◽  
And Oxidative Stress

Background/Aims: Previously, we demonstrated that blockade of the intracellular clearance systems in human retinal pigment epithelial (RPE) cells by MG-132 and bafilomycin A1 (BafA) induces NLRP3 inflammasome signaling. Here, we have explored the activation mechanisms behind this process. NLRP3 is an intracellular receptor detecting factors ranging from the endogenous alarmins and adenosine triphosphate (ATP) to ultraviolet radiation and solid particles. Due to the plethora of triggers, the activation of NLRP3 is often indirect and can be mediated through several alternative pathways. Potassium efflux, lysosomal rupture, and oxidative stress are currently the main mechanisms associated with many activators. Methods: NLRP3 inflammasomes were activated in human RPE cells by blocking proteasomes and autophagy using MG-132 and bafilomycin A1 (BafA), respectively. P2X7 inhibitor A740003, potassium chloride (KCl), and glyburide, or N-acetyl-L-cysteine (NAC), ammonium pyrrolidinedithiocarbamate (APDC), diphenyleneiodonium chloride (DPI), and mito-TEMPO were added to cell cultures in order to study the role of potassium efflux and oxidative stress, respectively. IL-1β was measured using the ELISA method. ATP levels and cathepsin B activity were examined using commercial kits, and ROS levels using the fluorescent dye 2´,7´-dichlorodihydrofluorescein diacetate (DCFDA). Results: Elevated extracellular potassium prevented the priming factor IL-1α from inducing the production of reactive oxygen species (ROS). It also prevented IL-1β release after exposure of primed cells to MG-132 and BafA. Inflammasome activation increased extracellular ATP levels, which did not appear to trigger significant potassium efflux. The activity of the lysosomal enzyme, cathepsin B, was reduced by MG-132 and BafA, suggesting that cathepsin B was not playing any role in this phenomenon. Instead, MG-132 triggered ROS production already 30 min after exposure, but treatment with antioxidants blocking NADPH oxidase and mitochondria-derived ROS significantly prevented IL-1β release after this activating signal. Conclusion: Our data suggest that oxidative stress strongly contributes to the NLRP3 inflammasome activation upon dysfunctional cellular clearance. Clarification of inflammasome activation mechanisms provides novel options for alleviating pathological inflammation present in aggregation diseases, such as age-related macular disease (AMD) and Alzheimer’s disease.

Beneficial Effect of Zinc Supplementation on Oxidative Stress, Cytokines, and NF-κB DNA Binding in Sickle Cell Disease Patients.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1203-1203 ◽  
Author(s):  
Bin Bao ◽  
Ananda Prasad ◽  
Frances W.J. Beck ◽  
Paul Swerdlow ◽  
Anupam Suneja
Keyword(s):  
Oxidative Stress ◽  
Placebo Group ◽  
Sickle Cell Disease ◽  
Dna Binding ◽  
Sickle Cell ◽  
Zinc Deficiency ◽  
Zinc Supplementation ◽  
P Value ◽  
Cell Disease ◽  
Tnf Α

Abstract Zinc deficiency is common in adult sickle-cell disease (SCD) patients, due to continued hemolysis and hyperzincuria. Growth retardation, hypogonadism, and immune dysfunctions due to zinc deficiency have been described in SCD patients. Our studies show that zinc has not only anti-inflammatory functions, but is also an antioxidant. We have previously shown that zinc supplementation to adult SCD patients decreased the incidences of infection and hospital admissions. We hypothesize that zinc supplementation improves T-helper cell and vascular endothelial cell activation, and decreases oxidative stress and NF-κB activation in SCD patients. To test this hypothesis, we recruited 36 ambulatory SCD (homozygous) patients (ages 18–47 years, 11 males and 7 females in each group) and randomly divided these into 2 groups. One group (n=18) received 25 mg zinc as acetate orally thrice a day for 3 months. The other group (n=18) received placebo. All these patients were free of pain crisis for 3 months and were not receiving hydroxyurea. The results indicate that zinc supplemented group had decreased incidence of infection in comparison to the placebo group (Chi square analysis: p=0.017). After 3 months of zinc supplementation, the plasma zinc level increased. The anti-oxidant power increased and the plasma levels of NO, lipid peroxidation products (MDA+HAE), DNA oxidation product (8-OHdG), and sVCAM-1 decreased in the zinc supplemented group, compared to the placebo group (p<0.05), as shown in the Table. Parameter Group Pre Post p value Δp value p value: Paired T-test; Pre (baseline) vs Post (6 m of supplementation). Δp value: T-test of the differences (pre vs post) between placebo vs Zn group) Zn (μM) Placebo 88.8±9.9 89.3±8.5 0.893 0.0001 Zn Supp. 85.6±9.3 104.2±15.0 0.0005 MDA+HAE (μM) Placebo 1.62±0.31 1.75±0.27 0.923 0.004 Zn Supp. 1.60±0.24 1.28±0.24 0.009 NO (μM) Placebo 78.5±12.6 76.7±11.8 0.256 0.051 Zn Supp. 75.2±11.2 60.9±17.1 0.021 8-OHdG (ng/ml) Plecebo 0.75±0.23 0.79±0.35 0.427 0.036 Zn Supp. 0.81±0.25 0.63±0.21 0.093 Antioxidant power (u/ml) Placebo 6.89±1.65 6.61±1.50 0.278 0.002 Zn Supp. 7.36±7.2 10.52±2.33 0.001 sVCAM-1 (ng/ml) Placebo 1587±359 1495±454 0.263 0.008 Zn Supp. 1434±455 1251±353 0.023 Relative levels of TNF-α, IL-1β, VCAM-1 mRNAs by RT-PCR were reduced in LPS-stimulated MNC isolated from zinc supplemented group, compared to placebo. In vitro zinc addition to the MNC isolated from placebo decreased TNF-α and IL-1β mRNAs. Zinc supplementation decreased TNF-induced NF-κB DNA binding (a biomarker of oxidative stress) by EMSA in isolated MNC, compared to placebo. Zinc supplementation also increased the relative level of IL-2 mRNA in PHA-stimulated MNC, compared to placebo. Our results showed that zinc supplementation to SCD patients decreased incidence of infection, and decreased oxidative stress markers. The mRNAs of TNF-α, IL-1β, and sVCAM-1, as well as TNF-induced NF-κB activation were also decreased in the zinc-supplemented subjects, suggesting that zinc supplementation may be beneficial to in SCD patients.

Activation of aconitase in mouse fast-twitch skeletal muscle during contraction-mediated oxidative stress

2007 ◽  
Vol 293 (3) ◽  
pp. C1154-C1159 ◽  
Author(s):  
Shi-Jin Zhang ◽  
Marie E. Sandström ◽  
Johanna T. Lanner ◽  
Anders Thorell ◽  
Håkan Westerblad ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Skeletal Muscle ◽  
Tricarboxylic Acid Cycle ◽  
Thigh Muscle ◽  
Ros Production ◽  
Atp Production ◽  
Aconitase Activity ◽  
Oxidation Reduction ◽  
Edl Muscle ◽  
Fast Twitch

Aconitase is a mitochondrial enzyme that converts citrate to isocitrate in the tricarboxylic acid cycle and is inactivated by reactive oxygen species (ROS). We investigated the effect of exercise/contraction, which is associated with elevated ROS production, on aconitase activity in skeletal muscle. Humans cycled at 75% of maximal workload, followed by six 60-s bouts at 125% of maximum workload. Biopsies were taken from the thigh muscle at rest and after the submaximal and supramaximal workloads. Isolated mouse extensor digitorum longus (EDL; fast twitch) and soleus (slow twitch) muscles were stimulated to perform repeated contractions for 10 min. Muscles were analyzed for enzyme activities and glutathione status. Exercise did not affect aconitase activity in human muscle despite increased oxidative stress, as judged by elevated levels of oxidized glutathione. Similarly, repeated contractions did not alter aconitase activity in soleus muscle. In contrast, repeated contractions significantly increased aconitase activity in EDL muscle by ∼50%, despite increased ROS production. This increase was not associated with a change in the amount of immunoreactive aconitase (Western blot) but was markedly inhibited by cyclosporin A, an inhibitor of the protein phosphatase calcineurin. Immunoprecipitation experiments demonstrated that aconitase was phosphorylated on serine residues. Aconitase in cell-free extracts was inactivated by the addition of the ROS hydrogen peroxide. In conclusion, the results suggest that aconitase activity can be regulated by at least two mechanisms: oxidation/reduction and phosphorylation/dephosphorylation. During contraction, a ROS-mediated inactivation of aconitase can be overcome, possibly by dephosphorylation of the enzyme. The dual-control system may be important in maintaining aerobic ATP production during muscle contraction.

scholarly journals The Charcot Marie Tooth Disease Mutation R94Q in MFN2 Decreases ATP Production but Increases Mitochondrial Respiration under Conditions of Mild Oxidative Stress

2019 ◽  
Author(s):  
Christina Wolf ◽  
Rahel Zimmermann ◽  
Osamah Thaher ◽  
Diones Bueno ◽  
Verena Wüllner ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Quality Control ◽  
Mitochondrial Respiration ◽  
Culture Conditions ◽  
Mitochondrial Quality Control ◽  
Mitofusin 2 ◽  
Charcot Marie Tooth ◽  
Atp Production ◽  
Charcot Marie Tooth Disease ◽  
Tooth Disease

Charcot-Marie-Tooth disease is a hereditary polyneuropathy caused by mutations in Mitofusin-2 (MFN2), a GTPase in the outer mitochondrial membrane involved in the regulation of mitochondrial fusion and bioenergetics. Autosomal-dominant inheritance of a R94Q mutation in MFN2 causes the axonal subtype 2A2A which is characterized by early onset and progressive atrophy of distal muscles caused by motoneuronal degeneration. Here, we studied mitochondrial shape, respiration, cytosolic and mitochondrial ATP content as well as mitochondrial quality control in MFN2-deficient fibroblasts stably expressing wildtype or R94Q MFN2. Under normal culture conditions, R94Q cells had slightly more fragmented mitochondria but similar mitochondrial oxygen consumption, membrane potential and ATP production. Mild oxidative stress procured by 100 µM hydrogen peroxide applied 24 h before analysis, however, significantly increased respiration but decreased mitochondrial ATP production only in R94Q cells. This was accompanied by increased glucose uptake and an upregulation of hexokinase 1 and pyruvate kinase M2 suggesting increased pyruvate shuttling into mitochondria. As these changes coincided with decreased levels of PINK1/Parkin-mediated mitophagy in R94Q cells, we conclude that the disease-causing R94Q mutation in MFN2 causes uncoupling of mitochondrial respiration from ATP production by a less efficient mitochondrial quality control.

scholarly journals Resvega Alleviates Hydroquinone-Induced Oxidative Stress in ARPE-19 Cells

2020 ◽  
Vol 21 (6) ◽  
pp. 2066 ◽  
Author(s):  
Niina Bhattarai ◽  
Eveliina Korhonen ◽  
Maija Toppila ◽  
Ali Koskela ◽  
Kai Kaarniranta ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Viability ◽  
Cigarette Smoke ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Enzyme Linked Immunosorbent Assay ◽  
Ros Production ◽  
Rpe Cells ◽  
Age Related ◽  
Dichlorofluorescin Diacetate

Retinal pigment epithelial (RPE) cells maintain homeostasis at the retina and they are under continuous oxidative stress. Cigarette smoke is a prominent environmental risk factor for age-related macular degeneration (AMD), which further increases the oxidant load in retinal tissues. In this study, we measured oxidative stress and inflammatory markers upon cigarette smoke-derived hydroquinone exposure on human ARPE-19 cells. In addition, we studied the effects of commercial Resvega product on hydroquinone-induced oxidative stress. Previously, it was observed that Resvega induces autophagy during impaired protein clearance in ARPE-19 cells, for which it has the potential to alleviate pro-inflammatory pathways. Cell viability was determined while using the lactate dehydrogenase (LDH) and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, and the cytokine levels were measured using the enzyme-linked immunosorbent assay (ELISA). Reactive oxygen species (ROS) production were measured using the 2′,7′-dichlorofluorescin diacetate (H2DCFDA) probe. Hydroquinone compromised the cell viability and increased ROS production in ARPE-19 cells. Resvega significantly improved cell viability upon hydroquinone exposure and reduced the release of interleukin (IL)-8 and monocytic chemoattractant protein (MCP)-1 from RPE cells. Resvega, N-acetyl-cysteine (NAC) and aminopyrrolidine-2,4-dicarboxylic acid (APDC) alleviated hydroquinone-induced ROS production in RPE cells. Collectively, our results indicate that hydroquinone induces cytotoxicity and increases oxidative stress through NADPH oxidase activity in RPE cells, and resveratrol-containing Resvega products prevent those adverse effects.

scholarly journals Protective Role ofPsoralea corylifoliaL. Seed Extract against Hepatic Mitochondrial Dysfunction Induced by Oxidative Stress or Aging

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Eunhui Seo ◽  
Yoon Sin Oh ◽  
Donghee Kim ◽  
Mi-Young Lee ◽  
Sungwook Chae ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Function ◽  
Hepg2 Cells ◽  
Peroxisome Proliferator ◽  
Ros Production ◽  
Protective Effects ◽  
Peroxisome Proliferator Activated Receptor ◽  
Atp Production ◽  
Genome Damage

The accumulation of oxidative damage and mitochondrial dysfunction is an important factor that contributes to aging. ThePsoralea corylifoliaseeds (PCS), commonly known as “Boh-Gol-Zhee” in Korea, have been used traditionally as a medicinal remedy. We investigated whether an extract of PCS has protective effects on oxidative stress and mitochondrial function in hepatocytes. The PCS extract showed an antisenescence effect on human diploid fibroblasts as evidenced by a decreased expression ofp16INK4amRNA and senescence-associatedβ-galactosidase staining. PCS extract treatment reduced H2O2-induced reactive oxygen species (ROS) production in HepG2 cells, inhibited ROS production in hepatocytes of aged mice, and increased superoxide dismutase activity. In H2O2-treated HepG2 cells, PCS extract treatment recovered ATP production. PCS extract treatment recovered the oxygen consumption rate and inhibited reduction of mitochondrial membrane potential induced by oxidative stress, suggesting improvement of mitochondrial function. In addition, PCS extract treatment recovered peroxisome proliferator-activated receptorγcoactivator 1αand carnitine palmitoyltransferase 1 mRNA and protein expression, and inhibited mitochondrial genome damage. Treatment with the major component of PCS extract, bakuchiol, also recovered mitochondrial dysfunction. On the basis of these results, we conclude that PCS extract inhibits ROS production and mitochondrial dysfunction induced by oxidative stress in hepatocytes.

scholarly journals The Charcot–Marie Tooth Disease Mutation R94Q in MFN2 Decreases ATP Production but Increases Mitochondrial Respiration under Conditions of Mild Oxidative Stress

Cells ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1289 ◽  
Author(s):  
Christina Wolf ◽  
Rahel Zimmermann ◽  
Osamah Thaher ◽  
Diones Bueno ◽  
Verena Wüllner ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Quality Control ◽  
Culture Conditions ◽  
Mitochondrial Quality Control ◽  
Mitochondrial Oxygen Consumption ◽  
Mitofusin 2 ◽  
Charcot Marie Tooth ◽  
Atp Production ◽  
Charcot Marie Tooth Disease ◽  
Tooth Disease

Charcot–Marie tooth disease is a hereditary polyneuropathy caused by mutations in Mitofusin-2 (MFN2), a GTPase in the outer mitochondrial membrane involved in the regulation of mitochondrial fusion and bioenergetics. Autosomal-dominant inheritance of a R94Q mutation in MFN2 causes the axonal subtype 2A2A which is characterized by early onset and progressive atrophy of distal muscles caused by motoneuronal degeneration. Here, we studied mitochondrial shape, respiration, cytosolic, and mitochondrial ATP content as well as mitochondrial quality control in MFN2-deficient fibroblasts stably expressing wildtype or R94Q MFN2. Under normal culture conditions, R94Q cells had slightly more fragmented mitochondria but a similar mitochondrial oxygen consumption, membrane potential, and ATP production as wildtype cells. However, when inducing mild oxidative stress 24 h before analysis using 100 µM hydrogen peroxide, R94Q cells exhibited significantly increased respiration but decreased mitochondrial ATP production. This was accompanied by increased glucose uptake and an up-regulation of hexokinase 1 and pyruvate kinase M2, suggesting increased pyruvate shuttling into mitochondria. Interestingly, these changes coincided with decreased levels of PINK1/Parkin-mediated mitophagy in R94Q cells. We conclude that mitochondria harboring the disease-causing R94Q mutation in MFN2 are more susceptible to oxidative stress, which causes uncoupling of respiration and ATP production possibly by a less efficient mitochondrial quality control.

scholarly journals The Charcot Marie Tooth Disease Mutation R94Q in MFN2 Decreases ATP Production but Increases Mitochondrial Respiration under Conditions of Mild Oxidative Stress

2019 ◽  
Author(s):  
Christina Wolf ◽  
Rahel Zimmermann ◽  
Osamah Thaher ◽  
Diones Bueno ◽  
Verena Wüllner ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Quality Control ◽  
Mitochondrial Respiration ◽  
Culture Conditions ◽  
Mitochondrial Quality Control ◽  
Mitofusin 2 ◽  
Charcot Marie Tooth ◽  
Atp Production ◽  
Charcot Marie Tooth Disease ◽  
Tooth Disease

Charcot-Marie-Tooth disease is a hereditary polyneuropathy caused by mutations in Mitofusin-2 (MFN2), a GTPase in the outer mitochondrial membrane involved in the regulation of mitochondrial fusion and bioenergetics. Autosomal-dominant inheritance of a R94Q mutation in MFN2 causes the axonal subtype 2A2A which is characterized by early onset and progressive atrophy of distal muscles caused by motoneuronal degeneration. Here, we studied mitochondrial shape, respiration, cytosolic and mitochondrial ATP content as well as mitochondrial quality control in MFN2-deficient fibroblasts stably expressing wildtype or R94Q MFN2. Under normal culture conditions, R94Q cells had slightly more fragmented mitochondria but a similar mitochondrial oxygen consumption, membrane potential and ATP production as wildtype cells. However, when inducing mild oxidative stress 24 h before analysis using 100 µM hydrogen peroxide, R94Q cells exhibited significantly increased respiration but decreased mitochondrial ATP production. This was accompanied by increased glucose uptake and an upregulation of hexokinase 1 and pyruvate kinase M2 suggesting increased pyruvate shuttling into mitochondria. As these changes coincided with decreased levels of PINK1/Parkin-mediated mitophagy in R94Q cells, we conclude that the disease-causing R94Q mutation in MFN2 causes uncoupling of mitochondrial respiration from ATP production by a less efficient mitochondrial quality control triggered by oxidative stress.

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