Selective NADH communication from α-ketoglutarate dehydrogenase to mitochondrial transhydrogenase prevents reactive oxygen species formation under reducing conditions in the heart

Abstract In heart failure, a functional block of complex I of the respiratory chain provokes superoxide generation, which is transformed to H2O2 by dismutation. The Krebs cycle produces NADH, which delivers electrons to complex I, and NADPH for H2O2 elimination via isocitrate dehydrogenase and nicotinamide nucleotide transhydrogenase (NNT). At high NADH levels, α-ketoglutarate dehydrogenase (α-KGDH) is a major source of superoxide in skeletal muscle mitochondria with low NNT activity. Here, we analyzed how α-KGDH and NNT control H2O2 emission in cardiac mitochondria. In cardiac mitochondria from NNT-competent BL/6N mice, H2O2 emission is equally low with pyruvate/malate (P/M) or α-ketoglutarate (α-KG) as substrates. Complex I inhibition with rotenone increases H2O2 emission from P/M, but not α-KG respiring mitochondria, which is potentiated by depleting H2O2-eliminating capacity. Conversely, in NNT-deficient BL/6J mitochondria, H2O2 emission is higher with α-KG than with P/M as substrate, and further potentiated by complex I blockade. Prior depletion of H2O2-eliminating capacity increases H2O2 emission from P/M, but not α-KG respiring mitochondria. In cardiac myocytes, downregulation of α-KGDH activity impaired dynamic mitochondrial redox adaptation during workload transitions, without increasing H2O2 emission. In conclusion, NADH from α-KGDH selectively shuttles to NNT for NADPH formation rather than to complex I of the respiratory chain for ATP production. Therefore, α-KGDH plays a key role for H2O2 elimination, but is not a relevant source of superoxide in heart. In heart failure, α-KGDH/NNT-dependent NADPH formation ameliorates oxidative stress imposed by complex I blockade. Downregulation of α-KGDH may, therefore, predispose to oxidative stress in heart failure.

Download Full-text

A new insight into the molecular hydrogen effect on coenzyme Q and mitochondrial function of rats

Canadian Journal of Physiology and Pharmacology ◽

10.1139/cjpp-2019-0281 ◽

2020 ◽

Vol 98 (1) ◽

pp. 29-34 ◽

Cited By ~ 4

Author(s):

Anna Gvozdjáková ◽

Jarmila Kucharská ◽

Branislav Kura ◽

Ol’ga Vančová ◽

Zuzana Rausová ◽

...

Keyword(s):

Oxidative Stress ◽

Oxidative Phosphorylation ◽

Respiratory Chain ◽

Mitochondrial Function ◽

Complex I ◽

Molecular Hydrogen ◽

Coenzyme Q ◽

Complex Ii ◽

Atp Production ◽

Q Cycle

Mitochondria are the major source of cellular energy metabolism. In the cardiac cells, mitochondria produce by way of the oxidative phosphorylation more than 90% of the energy supply in the form of ATP, which is utilized in many ATP-dependent processes, like cycling of the contractile proteins or maintaining ion gradients. Reactive oxygen species (ROS) are by-products of cellular metabolism and their levels are controlled by intracellular antioxidant systems. Imbalance between ROS and the antioxidant defense leads to oxidative stress and oxidative changes to cellular biomolecules. Molecular hydrogen (H2) has been proved as beneficial in the prevention and therapy of various diseases including cardiovascular disorders. It selectively scavenges hydroxyl radical and peroxynitrite, reduces oxidative stress, and has anti-inflammatory and anti-apoptotic effects. The effect of H2 on the myocardial mitochondrial function and coenzyme Q levels is not well known. In this paper, we demonstrated that consumption of H2-rich water (HRW) resulted in stimulated rat cardiac mitochondrial electron respiratory chain function and increased levels of ATP production by Complex I and Complex II substrates. Similarly, coenzyme Q9 levels in the rat plasma, myocardial tissue, and mitochondria were increased and malondialdehyde level in plasma was reduced after HRW administration. Based on obtained data, we hypothesize a new metabolic pathway of the H2 effect in mitochondria on the Q-cycle and in mitochondrial respiratory chain function. The Q-cycle contains three coenzyme Q forms: coenzyme Q in oxidized form (ubiquinone), radical form (semiquinone), or reduced form (ubiquinol). H2 may be a donor of both electron and proton in the Q-cycle and thus we can suppose stimulation of coenzyme Q production. When ubiquinone is reduced to ubiquinol, lipid peroxidation is reduced. Increased CoQ9 concentration can stimulate electron transport from Complex I and Complex II to Complex III and increase ATP production via mitochondrial oxidative phosphorylation. Our results indicate that H2 may function to prevent/treat disease states with disrupted myocardial mitochondrial function.

Download Full-text

Photobiomodulation and Oxidative Stress: 980 nm Diode Laser Light Regulates Mitochondrial Activity and Reactive Oxygen Species Production

Oxidative Medicine and Cellular Longevity ◽

10.1155/2021/6626286 ◽

2021 ◽

Vol 2021 ◽

pp. 1-11 ◽

Cited By ~ 2

Author(s):

Andrea Amaroli ◽

Claudio Pasquale ◽

Angelina Zekiy ◽

Anatoliy Utyuzh ◽

Stefano Benedicenti ◽

...

Keyword(s):

Oxidative Stress ◽

Reactive Oxygen Species ◽

Oxygen Consumption ◽

Respiratory Chain ◽

Laser Light ◽

Krebs Cycle ◽

Mitochondrial Activity ◽

Oxygen Species ◽

Atp Production ◽

And Oxidative Stress

Photobiomodulation with 808 nm laser light electively stimulates Complexes III and IV of the mitochondrial respiratory chain, while Complexes I and II are not affected. At the wavelength of 1064 nm, Complexes I, III, and IV are excited, while Complex II and some mitochondrial matrix enzymes seem to be not receptive to photons at that wavelength. Complex IV was also activated by 633 nm. The mechanism of action of wavelengths in the range 900–1000 nm on mitochondria is less understood or not described. Oxidative stress from reactive oxygen species (ROS) generated by mitochondrial activity is an inescapable consequence of aerobic metabolism. The antioxidant enzyme system for ROS scavenging can keep them under control. However, alterations in mitochondrial activity can cause an increment of ROS production. ROS and ATP can play a role in cell death, cell proliferation, and cell cycle arrest. In our work, bovine liver isolated mitochondria were irradiated for 60 sec, in continuous wave mode with 980 nm and powers from 0.1 to 1.4 W (0.1 W increment at every step) to generate energies from 6 to 84 J, fluences from 7.7 to 107.7 J/cm2, power densities from 0.13 to 1.79 W/cm2, and spot size 0.78 cm2. The control was equal to 0 W. The activity of the mitochondria’s complexes, Krebs cycle enzymes, ATP production, oxygen consumption, generation of ROS, and oxidative stress were detected. Lower powers (0.1–0.2 W) showed an inhibitory effect; those that were intermediate (0.3–0.7 W) did not display an effect, and the higher powers (0.8–1.1 W) induced an increment of ATP synthesis. Increasing the power (1.2–1.4 W) recovered the ATP production to the control level. The interaction occurred on Complexes III and IV, as well as ATP production and oxygen consumption. Results showed that 0.1 W uncoupled the respiratory chain and induced higher oxidative stress and drastic inhibition of ATP production. Conversely, 0.8 W kept mitochondria coupled and induced an increase of ATP production by increments of Complex III and IV activities. An augmentation of oxidative stress was also observed, probably as a consequence of the increased oxygen consumption and mitochondrial isolation experimental conditions. No effect was observed using 0.5 W, and no effect was observed on the enzymes of the Krebs cycle.

Download Full-text

Alpha-ketoglutarate dehydrogenase: a target and generator of oxidative stress

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2005.1764 ◽

2005 ◽

Vol 360 (1464) ◽

pp. 2335-2345 ◽

Cited By ~ 220

Author(s):

Laszlo Tretter ◽

Vera Adam-Vizi

Keyword(s):

Oxidative Stress ◽

Respiratory Chain ◽

Metabolic Flux ◽

Krebs Cycle ◽

Oxygen Species ◽

Catalytic Function ◽

Alpha Ketoglutarate Dehydrogenase ◽

Nadh Generation ◽

Metabolic Deficiency ◽

Ketoglutarate Dehydrogenase

Alpha-ketoglutarate dehydrogenase (α-KGDH) is a highly regulated enzyme, which could determine the metabolic flux through the Krebs cycle. It catalyses the conversion of α-ketoglutarate to succinyl-CoA and produces NADH directly providing electrons for the respiratory chain. α-KGDH is sensitive to reactive oxygen species (ROS) and inhibition of this enzyme could be critical in the metabolic deficiency induced by oxidative stress. Aconitase in the Krebs cycle is more vulnerable than α-KGDH to ROS but as long as α-KGDH is functional NADH generation in the Krebs cycle is maintained. NADH supply to the respiratory chain is limited only when α-KGDH is also inhibited by ROS. In addition being a key target, α-KGDH is able to generate ROS during its catalytic function, which is regulated by the NADH/NAD + ratio. The pathological relevance of these two features of α-KGDH is discussed in this review, particularly in relation to neurodegeneration, as an impaired function of this enzyme has been found to be characteristic for several neurodegenerative diseases.

Download Full-text

Comparison study of biogenic stimulators influence on reactive oxygen species formation by blood phagocytes in patients with heart failure in vitro

CARDIOVASCULAR THERAPY AND PREVENTION ◽

10.15829/1728-8800-2014-5-58-63 ◽

2014 ◽

pp. 58-63

Author(s):

E. I. Astashkin ◽

◽

M. P. Kruglova ◽

M. G. Glezer ◽

N. S. Orekhova ◽

...

Keyword(s):

Heart Failure ◽

Reactive Oxygen Species ◽

Reactive Oxygen ◽

Oxygen Species ◽

Comparison Study ◽

Reactive Oxygen Species Formation ◽

Species Formation ◽

Patients With Heart Failure

Download Full-text

Type I toxin-dependent generation of superoxide affects the persister life cycle of Escherichia coli

Scientific Reports ◽

10.1038/s41598-019-50668-1 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 4

Author(s):

Daniel Edelmann ◽

Bork A. Berghoff

Keyword(s):

Oxidative Stress ◽

Escherichia Coli ◽

Life Cycle ◽

Type I ◽

Oxygen Species ◽

Reactive Oxygen Species Formation ◽

Species Formation ◽

Genes Encoding ◽

Oxidative Challenge ◽

Detailed Work

Abstract Induction of growth stasis by bacterial toxins from chromosomal toxin-antitoxin systems is suspected to favor formation of multidrug-tolerant cells, named persisters. Recurrent infections are often attributed to resuscitation and regrowth of persisters upon termination of antibiotic therapy. Several lines of evidence point to oxidative stress as a crucial factor during the persister life cycle. Here, we demonstrate that the membrane-depolarizing type I toxins TisB, DinQ, and HokB have the potential to provoke reactive oxygen species formation in Escherichia coli. More detailed work with TisB revealed that mainly superoxide is formed, leading to activation of the SoxRS regulon. Deletion of the genes encoding the cytoplasmic superoxide dismutases SodA and SodB caused both a decline in TisB-dependent persisters and a delay in persister recovery upon termination of antibiotic treatment. We hypothesize that expression of depolarizing toxins during the persister formation process inflicts an oxidative challenge. The ability to counteract oxidative stress might determine whether cells will survive and how much time they need to recover from dormancy.

Download Full-text

Polyamine stimulation perturbs intracellular Ca2+ homeostasis and decreases viability of breast cancer BT474 cells

Zeitschrift für Naturforschung C ◽

10.1515/znc-2019-0119 ◽

2020 ◽

Vol 75 (3-4) ◽

pp. 65-73

Author(s):

Louis W.C. Chow ◽

Kar-Lok Wong ◽

Lian-Ru Shiao ◽

King-Chuen Wu ◽

Yuk-Man Leung

Keyword(s):

Breast Cancer ◽

Oxidative Stress ◽

Er Stress ◽

Cyclopiazonic Acid ◽

Oxygen Species ◽

Reactive Oxygen Species Formation ◽

Cytotoxic Effects ◽

Store Depletion ◽

Species Formation ◽

Cancer Cell Survival

AbstractIntracellular polyamines such as spermine and spermidine are essential to cell growth in normal and especially in cancer cells. However, whether extracellular polyamines affect cancer cell survival is unknown. We therefore examined the actions of extracellular polyamines on breast cancer BT474 cells. Our data showed that spermine, spermidine, and putrescine decreased cell viability by apoptosis. These polyamines also elicited Ca2+ signals, but the latter were unlikely triggered via Ca2+-sensing receptor (CaSR) as BT474 cells have been demonstrated previously to lack CaSR expression. Spermine-elicited Ca2+ response composed of both Ca2+ release and Ca2+ influx. Spermine caused a complete discharge of the cyclopiazonic acid (CPA)-sensitive Ca2+ pool and, expectedly, endoplasmic reticulum (ER) stress. The Ca2+ influx pore opened by spermine was Mn2+-impermeable, distinct from the CPA-triggered store-operated Ca2+ channel, which was Mn2+-permeable. Spermine cytotoxic effects were not due to oxidative stress, as spermine did not trigger reactive oxygen species formation. Our results therefore suggest that spermine acted on a putative polyamine receptor in BT474 cells, causing cytotoxicity by Ca2+ overload, Ca2+ store depletion, and ER stress.

Download Full-text

Kallistatin attenuates endothelial apoptosis through inhibition of oxidative stress and activation of Akt-eNOS signaling

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00591.2010 ◽

2010 ◽

Vol 299 (5) ◽

pp. H1419-H1427 ◽

Cited By ~ 49

Author(s):

Bo Shen ◽

Lin Gao ◽

Yi-Te Hsu ◽

Grant Bledsoe ◽

Makato Hagiwara ◽

...

Keyword(s):

Oxidative Stress ◽

Reactive Oxygen Species ◽

Endothelial Cells ◽

Endothelial Cell ◽

Oxygen Species ◽

Phosphatidylinositol 3 Kinase ◽

Reactive Oxygen Species Formation ◽

Endothelial Apoptosis ◽

Species Formation ◽

Tnf Α

Kallistatin is a regulator of vascular homeostasis capable of controlling a wide spectrum of biological actions in the cardiovascular and renal systems. We previously reported that kallistatin inhibited intracellular reactive oxygen species formation in cultured cardiac and renal cells. The present study was aimed to investigate the role and mechanisms of kallistatin in protection against oxidative stress-induced vascular injury and endothelial cell apoptosis. We found that kallistatin gene delivery significantly attenuated aortic superoxide formation and glomerular capillary loss in hypertensive DOCA-salt rats. In cultured endothelial cells, kallistatin suppressed TNF-α-induced cellular apoptosis, and the effect was blocked by the pharmacological inhibition of phosphatidylinositol 3-kinase and nitric oxide synthase (NOS) and by the knockdown of endothelial NOS (eNOS) expression. The transduction of endothelial cells with adenovirus expressing dominant-negative Akt abolished the protective effect of kallistatin on endothelial apoptosis and caspase activity. In addition, kallistatin inhibited TNF-α-induced reactive oxygen species formation and NADPH oxidase activity, and these effects were attenuated by phosphatidylinositol 3-kinase and NOS inhibition. Kallistatin also prevented the induction of Bim protein and mRNA expression by oxidative stress. Moreover, the downregulation of forkhead box O 1 (FOXO1) and Bim expression suppressed TNF-α-mediated endothelial cell death. Furthermore, the antiapoptotic actions of kallistatin were accompanied by Akt-mediated FOXO1 and eNOS phosphorylation, as well as increased NOS activity. These findings indicate a novel role of kallistatin in the protection against vascular injury and oxidative stress-induced endothelial apoptosis via the activation of Akt-dependent eNOS signaling.

Download Full-text

Olfactomedin 4 Is Essential for Superoxide Production and Sensitizes Oxidative Stress-Induced Apoptosis in Neutrophils.

Blood ◽

10.1182/blood.v114.22.1356.1356 ◽

2009 ◽

Vol 114 (22) ◽

pp. 1356-1356

Author(s):

Wenli Liu ◽

Yueqin Liu ◽

Ruihong Wang ◽

Cuiling Li ◽

Chuxia Deng ◽

...

Keyword(s):

Oxidative Stress ◽

Membrane Potential ◽

Mitochondrial Membrane Potential ◽

Respiratory Chain ◽

Complex I ◽

Mitochondrial Membrane ◽

Mitochondrial Respiratory Chain ◽

H2o2 Production ◽

Induced Apoptosis ◽

Mitochondrial Respiratory

Abstract Abstract 1356 Poster Board I-378 Introduction Olfactomedin 4 (OLFM4), also called hGC-1, GW112 and pDP4, was first identified and specifically expressed in hematopoietic myeloid cells. OLFM4 expression in myeloid cells is regulated by transcription factors, PU1 and NF-κB. It has significant homology in its C-terminal domain with other olfactomedin-related proteins. OLFM4 encodes a 510 amino acid N-linked glycoprotein. The exact biological function of OLFM4, especially in neutrophils, is currently undefined. To characterize the in vivo function of OLFM4, we generated OLFM4 deficient mice (OLFM4-/-) and investigated its potential role in neutrophil functioins. Results 1) In this study, we showed that OLFM4 is a secreted glycoprotein and is also localized in the mitochondria, cytoplasm and cell membrane fractions of neutrophils. We demonstrated that OLFM4 interacts with GRIM-19 (Genes associated with Retinoid-IFN-induced Mortality-19), an apoptosis related protein, in the neutrophil mitochondria using co-immuoprecipitation assay. GRIM-19 is a subunit of complex I of mitochondrial respiratory chain and is essential for maintenance of mitochondrial membrane potential. Our result suggests that OLFM4 appears to be a novel component of complex I of mitochondrial respiratory chain and may be involved in regulation of mitochondrial membrane potential. 2) Mice heterozygous (OLFM4+/-) and homozygous (OLFM4-/-) for the null mutation in OLFM4 appeared to have normal development, fertility, and viability relative to wild-type (WT) mice. Whole blood analysis, differential leukocyte counts, blood chemistry and bone marrow smears were normal in OLFM4-/- mice, suggesting that OLFM4 is not essential for normal development and hematopoiesis in mice. 3) In response to LPS, fMLP and E.coli bacteria challenge, neutrophils from OLFM4-/- mice showed significantly reduced superoxide (O2−) and hydrogen peroxide (H2O2) production compared with WT mice. These results suggest that OLFM4 is an essential component to mediate O2− and H2O2 production in the neutrophil mitochondria under inflammation stimuli. 4) Exogenous H2O2 induced neutrophil apoptosis in a time and dose dependent manner in WT mice, but this induction of apoptosis was significantly reduced in OLFM4-/- mice. This result suggests that OLFM4 sensitizes and mediates H2O2-induced apoptosis in neutrophils. 5) Furthermore, we demonstrated that H2O2-stimulated mitochondrial membrane permeability reduction and caspase-3 and caspase-9 activation were inhibited in the neutrophils of OLFM4-/- mice. This result confirmed our hypothesis that OLFM4 may be involved in maintenance of mitochondrial membrane potential and suggests that OLFM4 may have opposite role as GRIM-19. 6) Moreover, Bax association with mitochondria and the cytoplasmic translocation of Omi/HtrA2 and Smac/DIABLO in response to H2O2 were inhibited in the neutrophils of OLFM4-/- mice. Conclusion Our results suggest: 1) OLFM4 has multiple subcellular localizations including mitochondria, cytoplasm, and cell membrane in neutrophils. The interaction of OLFM4 with GRIM-19 in the mitochondria suggests that OLFM4 is novel component of complex I of mitochondrial respiratory chain in the mitochondria of neutrophils, 2) OLFM4 is a novel mitochondrial molecule that is essential for O2− and H2O2 production in the neutrophils in the presence of inflammation stimuli, 3) Loss of OLFM4 in neutrophils does not trigger spontaneous apoptosis. However, OLFM4 sensitizes oxidative stress-induced apoptosis in mouse neutrophils. OLFM4 is involved in the regulation of mitochondria membrane potential and sensitizes cytoplasmic translocation of Omi/HtrA2 and Smac/DIABLO and caspases-3 and caspase-9 mediated apoptosis in the presence of oxidative stress. Disclosures No relevant conflicts of interest to declare.

Download Full-text