scholarly journals Exacerbated Responses to Oxidative Stress by an Na+Load in Isolated Nerve Terminals: the Role of ATP Depletion and Rise of [Ca2+]i

2000 ◽  
Vol 20 (6) ◽  
pp. 2094-2103 ◽  
Author(s):  
Christos Chinopoulos ◽  
Laszlo Tretter ◽  
Adrienn Rozsa ◽  
Vera Adam-Vizi
Keyword(s):  
Oxidative Stress ◽  
Atp Depletion ◽  
Nerve Terminals

Abstract 125: Perturbation of Mitochondrial Calcium Uniporter Promotes Cardiac Oxidative Stress and Autophagy During Heart Failure

2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Sudarsan Rajan ◽  
Santhanam Shanmughapriya ◽  
Dhanendra Tomar ◽  
Zhiwei Dong ◽  
Joseph Y Cheung ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Heart Failure ◽  
Mouse Model ◽  
Atp Depletion ◽  
Regulatory Role ◽  
Mitochondrial Calcium ◽  
Mitochondrial Bioenergetics ◽  
Complex Assembly ◽  
New Findings

Mitochondrial calcium ([Ca 2+ ] m ) is essential for cardiomyocyte viability, and aberration of [Ca 2+ ] m is known to elicit multiple cardiac stress conditions associated with ATP depletion, reactive oxygen species, and mitochondrial permeability transition pore opening, all of which can lead to metabolic stress and the loss of dysfunctional mitochondria by aberrant autophagy. Elucidating the regulatory role of m itochondrial c alcium u niporter (MCU)-mediated [Ca 2+ ] m in modulating cardiac mitochondrial bioenergetics and autophagy has high significance and clinical impact for many pathophysiological processes. [Ca 2+ ] m is exquisitely controlled by the inner mitochondrial membrane uniporter, transporters, regulators and exchangers including MCU, MCUR1, EMRE, MICU1, MICU2 and LETM1. Our recently published findings revealed that Mitochondrial Ca 2+ Uniporter Regulator 1 (MCUR1) serves as a scaffold factor for uniporter complex assembly. We found that deletion of MCUR1 impaired [Ca 2+ ] m uptake, mitochondrial Ca 2+ current ( I MCU ) and mitochondrial bioenergetics and is associated with increased autophagy. Our new findings indicate that the impairment of [Ca 2+ ] m uptake exacerbated autophagy following ischemia-reperfusion (I/R) injury. In support of our mouse model, human failing hearts show that MCUR1 protein levels are markedly decreased and autophagy markers are increased, demonstrating a crucial link between [Ca 2+ ] m uptake and autophagy during heart failure. Additionally, our results reveal that either oxidation or disruption of human MCU Cys-97 (in mouse Cys-96; gain-of-function MCU C96A mutant) produces a conformational change within the N terminal β-grasp fold of MCU which promotes higher-order MCU complex assembly and increased I MCU activity and mitochondrial ROS levels. The results of our studies using a novel cardiac-specific MCUR1-KO model and a constitutively active global MCU C96A KI mouse model (CRISPR-Cas9 genome edited) elucidate the regulatory role of [Ca 2+ ] m in cardiac bioenergetics and autophagy during oxidative stress and myocardial infarction. Thus, targeting assembly and the activity of MCU complex will offer a new potential therapeutic target in the treatment of cardiomyopathy and heart failure.

scholarly journals Oxidant-induced inhibition of the plasma membrane Ca2+-ATPase in pancreatic acinar cells: role of the mitochondria

2008 ◽  
Vol 295 (5) ◽  
pp. C1247-C1260 ◽  
Author(s):  
Erin M. Baggaley ◽  
Austin C. Elliott ◽  
Jason I. E. Bruce
Keyword(s):  
Oxidative Stress ◽  
Plasma Membrane ◽  
Cell Injury ◽  
Mitochondrial Permeability Transition ◽  
Acinar Cells ◽  
Atp Depletion ◽  
Pancreatic Acinar Cells ◽  
Spatiotemporal Pattern ◽  
Mitochondrial Depolarization

Impairment of the normal spatiotemporal pattern of intracellular Ca2+ ([Ca2+]i) signaling, and in particular, the transition to an irreversible “Ca2+ overload” response, has been implicated in various pathophysiological states. In some diseases, including pancreatitis, oxidative stress has been suggested to mediate this Ca2+ overload and the associated cell injury. We have previously demonstrated that oxidative stress with hydrogen peroxide (H2O2) evokes a Ca2+ overload response and inhibition of plasma membrane Ca2+-ATPase (PMCA) in rat pancreatic acinar cells (Bruce JI and Elliott AC. Am J Physiol Cell Physiol 293: C938–C950, 2007). The aim of the present study was to further examine this oxidant-impaired inhibition of the PMCA, focusing on the role of the mitochondria. Using a [Ca2+]i clearance assay in which mitochondrial Ca2+ uptake was blocked with Ru-360, H2O2 (50 μM–1 mM) markedly inhibited the PMCA activity. This H2O2-induced inhibition of the PMCA correlated with mitochondrial depolarization (assessed using tetramethylrhodamine methylester fluorescence) but could occur without significant ATP depletion (assessed using Magnesium Green fluorescence). The H2O2-induced PMCA inhibition was sensitive to the mitochondrial permeability transition pore (mPTP) inhibitors, cyclosporin-A and bongkrekic acid. These data suggest that oxidant-induced opening of the mPTP and mitochondrial depolarization may lead to an inhibition of the PMCA that is independent of mitochondrial Ca2+ handling and ATP depletion, and we speculate that this may involve the release of a mitochondrial factor. Such a phenomenon may be responsible for the Ca2+ overload response, and for the transition between apoptotic and necrotic cell death thought to be important in many disease states.

792: Role of Oxidative Stress in Tumorigenic Potential of Bladder Cancer Cells

2005 ◽  
Vol 173 (4S) ◽  
pp. 214-215 ◽  
Author(s):  
Daniel Cho ◽  
Xiao Fang Ha ◽  
J. Andre Melendez ◽  
Louis J. Giorgi ◽  
Badar M. Mian
Keyword(s):  
Oxidative Stress ◽  
Bladder Cancer ◽  
Cancer Cells ◽  
Tumorigenic Potential ◽  
Bladder Cancer Cells

Role of Kupffer cells in the ethanol-induced oxidative stress in the liver

10.2741/a455 ◽  
1999 ◽  
Vol 4 (4) ◽  
pp. d589-595 ◽  
Author(s):  
Abraham P Bautista
Keyword(s):  
Oxidative Stress ◽  
Kupffer Cells
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