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.

Role of oxidative stress in left ventricular remodeling and heart failure after myocardial infarction

1999 ◽  
Vol 5 (3) ◽  
pp. 79
Author(s):  
Shintaro Kinugawa ◽  
Hiroyuki Tsutsui ◽  
Tomomi Ide ◽  
Hideo Ustumi ◽  
Nobuhiro Suematsu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Myocardial Infarction ◽  
Heart Failure ◽  
Ventricular Remodeling ◽  
Left Ventricular Remodeling ◽  
Left Ventricular

scholarly journals Role of Oxidative Stress in Heart Failure: Insights from Gene Transfer Studies

Biomedicines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1645
Author(s):  
Bart De Geest ◽  
Mudit Mishra
Keyword(s):  
Oxidative Stress ◽  
Heart Failure ◽  
Gene Therapy ◽  
Steady State ◽  
Gene Transfer ◽  
Oxidative Modification ◽  
Heme Oxygenase 1 ◽  
Therapy Studies ◽  
Pathological Remodeling

Under physiological circumstances, there is an exquisite balance between reactive oxygen species (ROS) production and ROS degradation, resulting in low steady-state ROS levels. ROS participate in normal cellular function and in cellular homeostasis. Oxidative stress is the state of a transient or a persistent increase of steady-state ROS levels leading to disturbed signaling pathways and oxidative modification of cellular constituents. It is a key pathophysiological player in pathological hypertrophy, pathological remodeling, and the development and progression of heart failure. The heart is the metabolically most active organ and is characterized by the highest content of mitochondria of any tissue. Mitochondria are the main source of ROS in the myocardium. The causal role of oxidative stress in heart failure is highlighted by gene transfer studies of three primary antioxidant enzymes, thioredoxin, and heme oxygenase-1, and is further supported by gene therapy studies directed at correcting oxidative stress linked to metabolic risk factors. Moreover, gene transfer studies have demonstrated that redox-sensitive microRNAs constitute potential therapeutic targets for the treatment of heart failure. In conclusion, gene therapy studies have provided strong corroborative evidence for a key role of oxidative stress in pathological remodeling and in the development of heart failure.

Cardiomyopathy, oxidative stress and impaired contractility in a rheumatoid arthritis mouse model

Heart ◽  
2018 ◽  
Vol 104 (24) ◽  
pp. 2026-2034 ◽  
Author(s):  
Gianluigi Pironti ◽  
Alex Bersellini-Farinotti ◽  
Nilesh M Agalave ◽  
Katalin Sandor ◽  
Teresa Fernandez-Zafra ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Oxidative Stress ◽  
Heart Failure ◽  
Mouse Model ◽  
Posttranslational Modifications ◽  
Contractile Function ◽  
Joint Inflammation ◽  
Left Ventricular ◽  
Increased Risk ◽  
Fractional Shortening

ObjectivesPatients with rheumatoid arthritis (RA) display an increased risk of heart failure independent of traditional cardiovascular risk factors. To elucidate myocardial disease in RA, we have investigated molecular and cellular remodelling of the heart in an established mouse model of RA.MethodsThe collagen antibody-induced arthritis (CAIA) RA mouse model is characterised by joint inflammation and increased inflammatory markers in the serum. We used CAIA mice in the postinflammatory phase that resembles medically controlled RA or RA in remission. Hearts were collected for cardiomyocyte isolation, biochemistry and histology analysis.ResultsHearts from mice subjected to CAIA displayed hypertrophy (heart/body weight, mean±SD: 5.9±0.8vs 5.1±0.7 mg/g, p<0.05), fibrosis and reduced left ventricular fractional shortening compared with control. Cardiomyocytes from CAIA mice showed reduced cytosolic [Ca2+]i transient amplitudes (F/F0, mean±SD: 3.0±1.2vs 3.6±1.5, p<0.05) that was linked to reductions in sarcoplasmic reticulum (SR) Ca2+ store (F/F0, mean±SD: 3.5±1.3vs 4.4±1.3, p<0.01) measured with Ca2+ imaging. This was associated to lower fractional shortening in the cardiomyocytes from the CAIA mice (%FS, mean±SD: 3.4±2.2 vs 4.6%±2.3%, p<0.05). Ca2+ handling proteins displayed oxidation-dependent posttranslational modifications that together with an increase in superoxide dismutase expression indicate a cell environment with oxidative stress.ConclusionsThis study shows that inflammation during active RA has long-term consequences on molecular remodelling and contractile function of the heart, which further supports that rheumatology patients should be followed for development of heart failure.

The Regulatory Role of MiR-203 in Oxidative Stress induced Cell Injury Through the CBS/H2S Pathway

Nitric Oxide ◽  
2021 ◽  
Author(s):  
Qiuyan Zhang ◽  
Zhuqing Shen ◽  
Yaqi Shen ◽  
Muye Ma ◽  
Hao Jue ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Injury ◽  
Regulatory Role

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

Improving mitochondrial bioenergetics under ischemic conditions increases warm ischemia tolerance in the kidney

2015 ◽  
Vol 308 (1) ◽  
pp. F11-F21 ◽  
Author(s):  
Hazel H. Szeto ◽  
Shaoyi Liu ◽  
Yi Soong ◽  
Alexander V. Birk
Keyword(s):  
Acute Kidney Injury ◽  
Partial Nephrectomy ◽  
Interstitial Fibrosis ◽  
Kidney Injury ◽  
Warm Ischemia ◽  
Atp Depletion ◽  
Cell Swelling ◽  
Mitochondrial Bioenergetics ◽  
New Findings ◽  
Ischemia Tolerance

Ischemia time during partial nephrectomy is strongly associated with acute and chronic renal injury. ATP depletion during warm ischemia inhibits ATP-dependent processes, resulting in cell swelling, cytoskeletal breakdown, and cell death. The duration of ischemia tolerated by the kidney depends on the amount of ATP that can be produced with residual substrates and oxygen in the tissue to sustain cell function. We previously reported that the rat can tolerate 30-min ischemia quite well but 45-min ischemia results in acute kidney injury and progressive interstitial fibrosis. Here, we report that pretreatment with SS-20 30 min before warm ischemia in the rat increased ischemia tolerance from 30 to 45 min. Histological examination of kidney tissues revealed that SS-20 reduced cytoskeletal breakdown and cell swelling after 45-min ischemia. Electron microscopy showed that SS-20 reduced mitochondrial matrix swelling and preserved cristae membranes, suggesting that SS-20 enhanced mitochondrial ATP synthesis under ischemic conditions. Studies with isolated kidney mitochondria showed dramatic reduction in state 3 respiration and respiratory control ratio after 45-min ischemia, and this was significantly improved by SS-20 treatment. These results suggest that SS-20 increases efficiency of the electron transport chain and improves coupling of oxidative phosphorylation. SS-20 treatment after ischemia also significantly reduced interstitial fibrosis. These new findings reveal that enhancing mitochondrial bioenergetics may be an important target for improving ischemia tolerance, and SS-20 may serve well for minimizing acute kidney injury and chronic kidney disease following surgical procedures such as partial nephrectomy and transplantation.

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