Imaging Cuprizone-Induced Mitochondrial Dysfunction

AbstractCuprizone is a copper chelator that induces mitochondrial dysfunction in myelin-producing oligodendrocytes and hepatic cells. Inhibition of oxidative phosphorylation has been proposed as a potential mechanism, but the exact relationship between shape changes and metabolic alterations is not well-understood. Here we explore how mitochondrial shape influences oxidative phosphorylation rates by performing simultaneous imaging and respiration measurements within intact cells. We observed that MO3.13 cells exposed to cuprizone undergo an initial increase in respiration followed by mitochondrial dysfunction and genetic dysregulation within 8 hours. Oxygen consumption was measured within 30 minutes of treatment and found to be elevated. This increase was followed by swelling of mitochondria over the first 8 hours, but preceded cell death by 24 hours. A transcriptomic analysis of early changes in cellular gene expression identified alterations within the electron transport chain, stress response pathways, and mitochondrial dynamics compared to control cells. These results suggest that pathological mitochondrial swelling is associated with increased oxygen consumption rates leading to transcriptional changes in respiratory complexes and ultimately mitochondrial failure.

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Impaired Mitochondrial Fusion and Oxidative Phosphorylation Triggered by High Glucose Is Mediated by Tom22 in Endothelial Cells

Oxidative Medicine and Cellular Longevity ◽

10.1155/2019/4508762 ◽

2019 ◽

Vol 2019 ◽

pp. 1-23 ◽

Cited By ~ 1

Author(s):

Yi Zeng ◽

Qi Pan ◽

Xiaoxia Wang ◽

Dongxiao Li ◽

Yajun Lin ◽

...

Keyword(s):

Endothelial Cells ◽

Oxidative Phosphorylation ◽

Mitochondrial Dysfunction ◽

High Glucose ◽

Mitochondrial Dynamics ◽

Umbilical Vein ◽

Vascular Complications ◽

Mitochondrial Fusion ◽

Mitochondrial Outer Membrane ◽

Atp Production

Much evidence demonstrates that mitochondrial dysfunction plays a crucial role in the pathogenesis of vascular complications of diabetes. However, the signaling pathways through which hyperglycemia leads to mitochondrial dysfunction of endothelial cells are not fully understood. Here, we treated human umbilical vein endothelial cells (HUVECs) with high glucose and examined the role of translocase of mitochondrial outer membrane (Tom) 22 on mitochondrial dynamics and cellular function. Impaired Tom22 expression and protein expression of oxidative phosphorylation (OXPHOS) as well as decreased mitochondrial fusion were observed in HUVECs treated with high glucose. The deletion of Tom22 resulted in reduced mitochondrial fusion and ATP production and increased apoptosis in HUVECs. The overexpression of Tom22 restored the balance of mitochondrial dynamics and OXPHOS disrupted by high glucose. Importantly, we found that Tom22 modulates mitochondrial dynamics and OXPHOS by interacting with mitofusin (Mfn) 1. Taken together, our findings demonstrate for the first time that Tom22 is a novel regulator of both mitochondrial dynamics and bioenergetic function and contributes to cell survival following high-glucose exposure.

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Alteration of Pseudomonas aeruginosa respiration by 4-(1-adamantyl)-phenol derivative

Biologija ◽

10.6001/biologija.v64i3.3828 ◽

2018 ◽

Vol 64 (3) ◽

Author(s):

Daria M. Dudikova ◽

Nina O. Vrynchanu ◽

Valentyna I. Nosar

Keyword(s):

Pseudomonas Aeruginosa ◽

Oxygen Consumption ◽

Oxidative Phosphorylation ◽

Respiratory Chain ◽

Structural Integrity ◽

Respiratory Control ◽

Endogenous Respiration ◽

Phenol Derivative ◽

Succinate Oxidation ◽

Intact Cells

Derivatives of 4-(1-adamantyl)-phenol are a promising class of antimicrobials affecting the structural integrity and functions of the bacterial cell membrane. The functioning of Pseudomonas aeruginosa respiratory chain and related system of oxidative phosphorylation was investigated before and after treatment with a derivative of 4-(1-adamantyl)-phenol (compound KVM-97). Oxygen consumption was measured polarographically with a Clark-type oxygen electrode. KVM-97 was tested at 0.5× and 1.0× MIC (minimum inhibitory concentration). Specific substrates of the respiratory chain (either 3.0 mM glutamate with 2.0 mM malonate or 3.0 mM succinate with 5.0 μM rotenone) were used. All reactions were stimulated by addition of ADP (0.2 mmol). It was found that at tested concentrations, KVM-97 inhibited the endogenous respiration and substrate oxidation in P. aeruginosa cells. The inhibiting effect was dose-dependent and more pronounced with succinate oxidation rather than glutamate oxidation. The respiratory control index value (RCI) in compound-treated cells was in average 1.5 times lower compared to the intact cells. The decrease in the RCI was related to changing the oxygen uptake rates in state 3 and state 4, which indicate the uncoupling of respiration and oxidative phosphorylation. The data obtained showed that 4-(1-adamantyl)-phenol derivative inhibits oxygen consumption and has uncoupling effects in P. aeruginosa cells.

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Dysfunctional Mitochondrial Dynamic and Oxidative Phosphorylation Precedes Cardiac Dysfunction in R120G‐αB‐Crystallin‐Induced Desmin‐Related Cardiomyopathy

Journal of the American Heart Association ◽

10.1161/jaha.120.017195 ◽

2020 ◽

Vol 9 (23) ◽

Author(s):

Shafiul Alam ◽

Chowdhury S. Abdullah ◽

Richa Aishwarya ◽

Mahboob Morshed ◽

Sadia S. Nitu ◽

...

Keyword(s):

Oxidative Phosphorylation ◽

Pyruvate Dehydrogenase ◽

Cardiac Dysfunction ◽

Electron Transport Chain ◽

Mitochondrial Dynamics ◽

Pyruvate Dehydrogenase Complex ◽

Chain Complex ◽

Contractile Dysfunction ◽

Transport Chain ◽

Complex Activities

Background The mutated α‐B‐Crystallin (CryAB R120G ) mouse model of desmin‐related myopathy (DRM) shows an age‐dependent onset of pathologic cardiac remodeling and progression of heart failure. CryAB R120G expression in cardiomyocytes affects the mitochondrial spatial organization within the myofibrils, but the molecular perturbation within the mitochondria in the relation of the overall course of the proteotoxic disease remains unclear. Methods and Results CryAB R120G mice show an accumulation of electron‐dense aggregates and myofibrillar degeneration associated with the development of cardiac dysfunction. Though extensive studies demonstrated that these altered ultrastructural changes cause cardiac contractility impairment, the molecular mechanism of cardiomyocyte death remains elusive. Here, we explore early pathological processes within the mitochondria contributing to the contractile dysfunction and determine the pathogenic basis for the heart failure observed in the CryAB R120G mice. In the present study, we report that the CryAB R120G mice transgenic hearts undergo altered mitochondrial dynamics associated with increased level of dynamin‐related protein 1 and decreased level of optic atrophy type 1 as well as mitofusin 1 over the disease process. In association with these changes, an altered level of the components of mitochondrial oxidative phosphorylation and pyruvate dehydrogenase complex regulatory proteins occurs before the manifestation of pathologic adverse remodeling in the CryAB R120G hearts. Mitochondria isolated from CryAB R120G transgenic hearts without visible pathology show decreased electron transport chain complex activities and mitochondrial respiration. Taken together, we demonstrated the involvement of mitochondria in the pathologic remodeling and progression of DRM‐associated cellular dysfunction. Conclusions Mitochondrial dysfunction in the form of altered mitochondrial dynamics, oxidative phosphorylation and pyruvate dehydrogenase complex proteins level, abnormal electron transport chain complex activities, and mitochondrial respiration are evident on the CryAB R120G hearts before the onset of detectable pathologies and development of cardiac contractile dysfunction.

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Ischemic Preconditioning Preserves Mitochondrial Function after Global Cerebral Ischemia in Rat Hippocampus

Journal of Cerebral Blood Flow & Metabolism ◽

10.1097/00004647-200112000-00004 ◽

2001 ◽

Vol 21 (12) ◽

pp. 1401-1410 ◽

Cited By ~ 85

Author(s):

Kunjan R. Dave ◽

Isabel Saul ◽

Raul Busto ◽

Myron D. Ginsberg ◽

Thomas J. Sick ◽

...

Keyword(s):

Oxygen Consumption ◽

Cerebral Ischemia ◽

Oxidative Phosphorylation ◽

Ischemic Preconditioning ◽

Global Cerebral Ischemia ◽

Mitochondrial Oxidative Phosphorylation ◽

Ischemic Insult ◽

Bilateral Carotid ◽

Consumption Rates ◽

Induction Of Tolerance

Ischemic tolerance in brain develops when sublethal ischemic insults occur before “lethal” cerebral ischemia. Two windows for the induction of tolerance by ischemic preconditioning (IPC) have been proposed: one that occurs within 1 hour after IPC, and another that occurs 1 or 2 days after IPC. The authors tested the hypotheses that IPC would reduce or prevent ischemia-induced mitochondrial dysfunction. IPC and ischemia were produced by bilateral carotid occlusions and systemic hypotension (50 mm Hg) for 2 and 10 minutes, respectively. Nonsynaptosomal mitochondria were harvested 24 hours after the 10-minute “test” ischemic insult. No significant changes were observed in the oxygen consumption rates and activities for hippocampal mitochondrial complexes I to IV between the IPC and sham groups. Twenty-four hours of reperfusion after 10 minutes of global ischemia (without IPC) promoted significant decreases in the oxygen consumption rates in presence of substrates for complexes I and II compared with the IPC and sham groups. These data suggest that IPC protects the integrity of mitochondrial oxidative phosphorylation after cerebral ischemia.

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Oxygen consumption and metabolite concentrations during transitions between different work intensities in heart

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00004.2006 ◽

2006 ◽

Vol 291 (3) ◽

pp. H1466-H1474 ◽

Cited By ~ 14

Author(s):

Bernard Korzeniewski

Keyword(s):

Oxygen Consumption ◽

Steady State ◽

Oxidative Phosphorylation ◽

Activation Mechanism ◽

General Idea ◽

Experimental Systems ◽

In Silico Studies ◽

Metabolite Concentrations ◽

Consumption Rates ◽

Parallel Activation

Steady-state metabolite (ADP, ATP, Pi, PCr, and NADH) concentrations usually differ little between different workloads with significantly different oxygen consumption rates in the heart. However, during transitions between steady states, metabolite concentrations may in some cases change transiently, exhibiting a significant overshoot or undershoot, whereas in other cases they approach near-exponentially new steady-state values. Oxygen consumption rate usually reaches the new steady-state value very quickly (within a few seconds). The present in silico studies, performed using a previously developed computer model of oxidative phosphorylation in the heart, demonstrate that such a behavior of the oxidative phosphorylation system can be reproduced only under the assumption that ATP usage, substrate dehydrogenation, and (particular steps of) oxidative phosphorylation are directly activated to a similar extend by some cytosolic factor/mechanism during transition from low work to high work (the so-called parallel-activation mechanism). Computer simulations show that some differences observed between different experimental systems can be explained by a slightly different balance of the activation of particular components of the system and/or by a delay in time of the activation/inactivation of substrate dehydrogenation and oxidative phosphorylation during low-to-high and high-to-low work transitions. Thus the presented theoretical approach offers a general idea that is able to unify, at least semiquantitatively, different experimental data available in the literature.

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Energy Metabolism Disturbances in Cell Models of PARK2 CNV Carriers with ADHD

Journal of Clinical Medicine ◽

10.3390/jcm9124092 ◽

2020 ◽

Vol 9 (12) ◽

pp. 4092

Author(s):

Viola Stella Palladino ◽

Andreas G. Chiocchetti ◽

Lukas Frank ◽

Denise Haslinger ◽

Rhiannon McNeill ◽

...

Keyword(s):

Oxygen Consumption ◽

Energy Metabolism ◽

Mitochondrial Dynamics ◽

Control Cell ◽

Copy Number Variants ◽

Atp Production ◽

Cellular Models ◽

Gene And Protein Expression ◽

Consumption Rates ◽

Cellular Phenotypes

The main goal of the present study was the identification of cellular phenotypes in attention-deficit-/hyperactivity disorder (ADHD) patient-derived cellular models from carriers of rare copy number variants (CNVs) in the PARK2 locus that have been previously associated with ADHD. Human-derived fibroblasts (HDF) were cultured and human-induced pluripotent stem cells (hiPSC) were reprogrammed and differentiated into dopaminergic neuronal cells (mDANs). A series of assays in baseline condition and in different stress paradigms (nutrient deprivation, carbonyl cyanide m-chlorophenyl hydrazine (CCCP)) focusing on mitochondrial function and energy metabolism (ATP production, basal oxygen consumption rates, reactive oxygen species (ROS) abundance) were performed and changes in mitochondrial network morphology evaluated. We found changes in PARK2 CNV deletion and duplication carriers with ADHD in PARK2 gene and protein expression, ATP production and basal oxygen consumption rates compared to healthy and ADHD wildtype control cell lines, partly differing between HDF and mDANs and to some extent enhanced in stress paradigms. The generation of ROS was not influenced by the genotype. Our preliminary work suggests an energy impairment in HDF and mDAN cells of PARK2 CNV deletion and duplication carriers with ADHD. The energy impairment could be associated with the role of PARK2 dysregulation in mitochondrial dynamics.

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Simultaneous evaluation of substrate-dependent oxygen consumption rates and mitochondrial membrane potential by TMRM and safranin in cortical mitochondria

Bioscience Reports ◽

10.1042/bsr20150244 ◽

2016 ◽

Vol 36 (1) ◽

Cited By ~ 15

Author(s):

Subir Roy Chowdhury ◽

Jelena Djordjevic ◽

Benedict C. Albensi ◽

Paul Fernyhough

Keyword(s):

Oxygen Consumption ◽

Membrane Potential ◽

Mitochondrial Dysfunction ◽

Mitochondrial Membrane Potential ◽

Mitochondrial Membrane ◽

Mitochondrial Bioenergetics ◽

Respiration Rates ◽

Pathological Conditions ◽

Simultaneous Evaluation ◽

Consumption Rates

Simultaneous evaluation of two mitochondrial bioenergetics parameters, respiration rates and mitochondrial membrane potential (mtMP) can be useful to determine the mitochondrial dysfunction under various pathological conditions including neurodegenerative diseases and diabetes.

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Bioenergetics During Calvarial Osteoblast Differentiation Reflect Strain Differences in Bone Mass

Endocrinology ◽

10.1210/en.2013-1974 ◽

2014 ◽

Vol 155 (5) ◽

pp. 1589-1595 ◽

Cited By ~ 60

Author(s):

Anyonya R. Guntur ◽

Phuong T. Le ◽

Charles R. Farber ◽

Clifford J. Rosen

Keyword(s):

Oxygen Consumption ◽

Bone Formation ◽

Oxidative Phosphorylation ◽

Bone Mass ◽

Osteoblast Differentiation ◽

Strain Differences ◽

Cellular Respiration ◽

Extracellular Acidification ◽

F1 Hybrid ◽

Consumption Rates

Osteoblastogenesis is the process by which mesenchymal stem cells differentiate into osteoblasts that synthesize collagen and mineralize matrix. The pace and magnitude of this process are determined by multiple genetic and environmental factors. Two inbred strains of mice, C3H/HeJ and C57BL/6J, exhibit differences in peak bone mass and bone formation. Although all the heritable factors that differ between these strains have not been elucidated, a recent F1 hybrid expression panel (C3H × B6) revealed major genotypic differences in osteoblastic genes related to cellular respiration and oxidative phosphorylation. Thus, we hypothesized that the metabolic rate of energy utilization by osteoblasts differed by strain and would ultimately contribute to differences in bone formation. In order to study the bioenergetic profile of osteoblasts, we measured oxygen consumption rates (OCR) and extracellular acidification rates (ECAR) first in a preosteoblastic cell line MC3T3-E1C4 and subsequently in primary calvarial osteoblasts from C3H and B6 mice at days 7, 14, and 21 of differentiation. During osteoblast differentiation in media containing ascorbic acid and β-glycerophosphate, all 3 cell types increased their oxygen consumption and extracellular acidification rates compared with the same cells grown in regular media. These increases are sustained throughout differentiation. Importantly, C3H calvarial osteoblasts had greater oxygen consumption rates than B6 consistent with their in vivo phenotype of higher bone formation. Interestingly, osteoblasts utilized both oxidative phosphorylation and glycolysis during the differentiation process although mature osteoblasts were more dependent on glycolysis at the 21-day time point than oxidative phosphorylation. Thus, determinants of oxygen consumption reflect strain differences in bone mass and provide the first evidence that during collagen synthesis osteoblasts use both glycolysis and oxidative phosphorylation to synthesize and mineralize matrix.

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