scholarly journals Cardiolipin promotes electron transport between ubiquinone and complex I to rescue PINK1 deficiency

2017 ◽  
Vol 216 (3) ◽  
pp. 695-708 ◽  
Author(s):  
Melissa Vos ◽  
Ann Geens ◽  
Claudia Böhm ◽  
Liesbeth Deaulmerie ◽  
Jef Swerts ◽  
...  
Keyword(s):  
Electron Transport ◽  
Complex I ◽  
Fatty Acid Synthase ◽  
Induced Pluripotent Stem Cell ◽  
Mitochondrial Inner Membrane ◽  
Mitochondrial Defects ◽  
Mouse Cells ◽  
Induced Pluripotent ◽  
Specific Lipid ◽  
Pharmacologic Inhibition

PINK1 is mutated in Parkinson’s disease (PD), and mutations cause mitochondrial defects that include inefficient electron transport between complex I and ubiquinone. Neurodegeneration is also connected to changes in lipid homeostasis, but how these are related to PINK1-induced mitochondrial dysfunction is unknown. Based on an unbiased genetic screen, we found that partial genetic and pharmacological inhibition of fatty acid synthase (FASN) suppresses toxicity induced by PINK1 deficiency in flies, mouse cells, patient-derived fibroblasts, and induced pluripotent stem cell–derived dopaminergic neurons. Lower FASN activity in PINK1 mutants decreases palmitate levels and increases the levels of cardiolipin (CL), a mitochondrial inner membrane–specific lipid. Direct supplementation of CL to isolated mitochondria not only rescues the PINK1-induced complex I defects but also rescues the inefficient electron transfer between complex I and ubiquinone in specific mutants. Our data indicate that genetic or pharmacologic inhibition of FASN to increase CL levels bypasses the enzymatic defects at complex I in a PD model.

scholarly journals Metabolic rescue ameliorates mitochondrial encephalo-cardiomyopathy in murine and human iPSC models of Leigh syndrome

2022 ◽  
Author(s):  
Jin-Young Yoon ◽  
Nastaran Daneshgar ◽  
Yi Chu ◽  
Biyi Chen ◽  
Marco Hefti ◽  
...  
Keyword(s):  
Diastolic Dysfunction ◽  
Complex I ◽  
Neuronal Apoptosis ◽  
Induced Pluripotent Stem Cell ◽  
Leigh Syndrome ◽  
Metabolic Derangement ◽  
Nicotinamide Riboside ◽  
Cardiac Sodium Channel ◽  
Induced Pluripotent ◽  
Human Ipsc

Mice with deletion of complex I subunit Ndufs4 develop mitochondrial encephalomyopathy resembling Leigh syndrome (LS). We report that LS mice also develop severe cardiac bradyarrhythmia and diastolic dysfunction. Human induced pluripotent stem cell-derived cardiomyocytes (iPS-CMs) with Ndufs4 deletion recapitulate LS cardiomyopathy. Mechanistically, we demonstrate a direct link between complex I deficiency, decreased intracellular NAD+/ NADH and bradyarrhythmia, mediated by hyperacetylation of the cardiac sodium channel NaV1.5, particularly at K1479 site. Neuronal apoptosis in the cerebellar and midbrain regions in LS mice was associated with hyperacetylation of p53 and activation of microglia. Targeted metabolomics revealed increases in several amino acids and citric acid cycle intermediates, likely due to impairment of NAD+-dependent dehydrogenases, and a substantial decrease in reduced Glutathione (GSH). Metabolic rescue by nicotinamide riboside (NR) supplementation increased intracellular NAD+/ NADH, restored metabolic derangement, reversed protein hyperacetylation through NAD+-dependent Sirtuin deacetylase, and ameliorated cardiomyopathic phenotypes, concomitant with improvement of NaV1.5 current and SERCA2a function measured by Ca2+-transients. NR also attenuated neuronal apoptosis and microglial activation in the LS brain and human iPS-derived neurons with Ndufs4 deletion. Our study reveals direct mechanistic explanations of the observed cardiac bradyarrhythmia, diastolic dysfunction and neuronal apoptosis in mouse and human iPSC models of LS.

scholarly journals Superoxide production by NADH:ubiquinone oxidoreductase (complex I) depends on the pH gradient across the mitochondrial inner membrane

2004 ◽  
Vol 382 (2) ◽  
pp. 511-517 ◽  
Author(s):  
Adrian J. LAMBERT ◽  
Martin D. BRAND
Keyword(s):  
Membrane Potential ◽  
Electron Transport ◽  
Complex I ◽  
Superoxide Production ◽  
Ph Gradient ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Protonmotive Force ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Reverse Electron Transport

The relationship between protonmotive force and superoxide production by mitochondria is poorly understood. To address this issue, the rate of superoxide production from complex I of rat skeletal muscle mitochondria incubated under a variety of conditions was assessed. By far, the largest rate of superoxide production was from mitochondria respiring on succinate; this rate was almost abolished by rotenone or piericidin, indicating that superoxide production from complex I is large under conditions of reverse electron transport. The high rate of superoxide production by complex I could also be abolished by uncoupler, confirming that superoxide production is sensitive to protonmotive force. It was inhibited by nigericin, suggesting that it is more dependent on the pH gradient across the mitochondrial inner membrane than on the membrane potential. These effects were examined in detail, leading to the conclusions that the effect of protonmotive force was mostly direct, and not indirect through changes in the redox state of the ubiquinone pool, and that the production of superoxide by complex I during reverse electron transport was at least 3-fold more sensitive to the pH gradient than to the membrane potential.

Use of 3D culture systems to generate human induced pluripotent stem cell-derived [beta]-cells in vitro

2018 ◽  
Author(s):  
Fantuzzi Federica ◽  
Toivonen Sanna ◽  
Schiavo Andrea Alex ◽  
Pachera Nathalie ◽  
Rajaei Bahareh ◽  
...  
Keyword(s):  
Stem Cell ◽  
Beta Cells ◽  
Pluripotent Stem Cell ◽  
3D Culture ◽  
Induced Pluripotent Stem Cell ◽  
Culture Systems ◽  
Induced Pluripotent

New Molecular Scaffolds for Fluorescent Voltage Indicators

2018 ◽  
Author(s):  
Steven Boggess ◽  
Shivaani Gandhi ◽  
Brian Siemons ◽  
Nathaniel Huebsch ◽  
Kevin Healy ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Action Potentials ◽  
Induced Pluripotent Stem Cell ◽  
Molecular Wire ◽  
Voltage Sensing ◽  
Design Synthesis ◽  
Cardiac Action ◽  
Action Potential Waveform ◽  
Induced Pluripotent ◽  
Voltage Sensing Domain

<div> <p>The ability to non-invasively monitor membrane potential dynamics in excitable cells like neurons and cardiomyocytes promises to revolutionize our understanding of the physiology and pathology of the brain and heart. Here, we report the design, synthesis, and application of a new class of fluorescent voltage indicator that makes use of a fluorene-based molecular wire as a voltage sensing domain to provide fast and sensitive measurements of membrane potential in both mammalian neurons and human-derived cardiomyocytes. We show that the best of the new probes, fluorene VoltageFluor 2 (fVF 2) readily reports on action potentials in mammalian neurons, detects perturbations to cardiac action potential waveform in human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes, shows a substantial decrease in phototoxicity compared to existing molecular wire-based indicators, and can monitor cardiac action potentials for extended periods of time. Together, our results demonstrate the generalizability of a molecular wire approach to voltage sensing and highlights the utility of fVF 2 for interrogating membrane potential dynamics.</p> </div>

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