scholarly journals Parkinson’s disease‒associated VPS35 mutant reduces mitochondrial membrane potential and impairs PINK1/Parkin-mediated mitophagy

2020 ◽  
Author(s):  
Kai Yu Ma ◽  
Michiel R Fokkens ◽  
Fulvio Reggiori ◽  
Muriel Mari ◽  
Dineke S Verbeek
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Steady State ◽  
Membrane Potential ◽  
Cell Surface ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Pathogenic Mechanism ◽  
Mitochondrial Potential

Abstract Background:Mitochondrial dysfunction plays a prominent role in the pathogenesis of Parkinson’s disease (PD), and several genes linked to familial PD, including PINK1 and PARK2, are directly involved in processes such as mitophagy that maintain mitochondrial health. The dominant p.D620N variant in VPS35 has also been associated to familial PD but has not been functionally connected to PINK1 and PARK2. Methods: To better mimic and study the patient situation, we used CRISPR-Cas9 to generate heterozygous human SH-SY5Y cells carrying the PD-associated D620N variant in VPS35. These cells were treated with the protonophore CCCP to induce PINK1/Parkin-mediated mitophagy, which was assessed using biochemical and microscopy approaches. Results:Mitochondria in VPS35-D620N cells exhibited reduced mitochondrial membrane potential and appeared to already be damaged at steady state. As a result, the mitochondria of these cells were desensitized to CCCP-induced collapse in mitochondrial potential, as they displayed altered fragmentation and were unable to accumulate PINK1 at their surface upon this insult. Consequently, Parkin recruitment to the cell surface was inhibited and initiation of PINK1/Parkin-dependent mitophagy is impaired. Conclusion:Our findings extend the pool of evidence that the p.D620N mutant VPS35 causes mitochondrial dysfunction and suggest a converging pathogenic mechanism between VPS35, PINK1 and Parkin in PD.

scholarly journals Parkinson’s disease–associated VPS35 mutant reduces mitochondrial membrane potential and impairs PINK1/Parkin-mediated mitophagy

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Kai Yu Ma ◽  
Michiel R. Fokkens ◽  
Fulvio Reggiori ◽  
Muriel Mari ◽  
Dineke S. Verbeek
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Membrane Potential ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Membrane Potential ◽  
Ubiquitin Ligase ◽  
Mitochondrial Membrane ◽  
Mitochondrial Potential ◽  
Carbonyl Cyanide ◽  
Vacuolar Protein

Abstract Background Mitochondrial dysfunction plays a prominent role in the pathogenesis of Parkinson’s disease (PD), and several genes linked to familial PD, including PINK1 (encoding PTEN-induced putative kinase 1 [PINK1]) and PARK2 (encoding the E3 ubiquitin ligase Parkin), are directly involved in processes such as mitophagy that maintain mitochondrial health. The dominant p.D620N variant of vacuolar protein sorting 35 ortholog (VPS35) gene is also associated with familial PD but has not been functionally connected to PINK1 and PARK2. Methods To better mimic and study the patient situation, we used CRISPR-Cas9 to generate heterozygous human SH-SY5Y cells carrying the PD-associated D620N variant of VPS35. These cells were treated with a protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) to induce the PINK1/Parkin-mediated mitophagy, which was assessed using biochemical and microscopy approaches. Results Mitochondria in the VPS35-D620N cells exhibited reduced mitochondrial membrane potential and appeared to already be damaged at steady state. As a result, the mitochondria of these cells were desensitized to the CCCP-induced collapse in mitochondrial potential, as they displayed altered fragmentation and were unable to accumulate PINK1 at their surface upon this insult. Consequently, Parkin recruitment to the cell surface was inhibited and initiation of the PINK1/Parkin-dependent mitophagy was impaired. Conclusion Our findings extend the pool of evidence that the p.D620N mutation of VPS35 causes mitochondrial dysfunction and suggest a converging pathogenic mechanism among VPS35, PINK1 and Parkin in PD.

scholarly journals Products of the Parkinson's-disease related glyoxalase DJ-1, D-lactate and glycolate, support mitochondrial membrane potential and neuronal survival

2014 ◽  
Author(s):  
Yusuke Toyoda ◽  
Cihan Erkut ◽  
Francisco Pan-Montojo ◽  
Sebastian Boland ◽  
Martin P. Stewart ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Dopaminergic Neurons ◽  
Mitochondrial Membrane ◽  
Mitochondrial Activity ◽  
Mitochondrial Potential ◽  
Environmental Toxin ◽  
Lactic Acids

Parkinson's disease is associated with mitochondrial decline in dopaminergic neurons of the substantia nigra. One of the genes, DJ- 1/PARK7, linked with the onset of Parkinson’s disease, belongs to a novel glyoxalase family and influences mitochondrial activity. It has been assumed that glyoxalases fulfill this task by detoxifying aggressive aldehyde by-products of metabolism. Here we show that supplying either D-lactate or glycolate, products of DJ-1, rescues the requirement for the enzyme in maintenance of mitochondrial potential. We further show that glycolic acid and D-lactic acid can elevate lowered mitochondrial membrane potential caused by silencing PINK-1, another Parkinson's related gene, as well as by paraquat, an environmental toxin known to be linked with Parkinson's disease. We propose that DJ-1 and consequently its products are components of a novel pathway that stabilizes mitochondria during cellular stress. We go on to show that survival of cultured mesencephalic dopaminergic neurons, defective in Parkinson's disease, is enhanced by glycolate and D-lactate. Because glycolic and D-lactic acids occur naturally, they are therefore a potential therapeutic route for treatment or prevention of Parkinson's disease.

scholarly journals Platelet mitochondrial membrane potential in Parkinson's disease

2014 ◽  
Vol 2 (1) ◽  
pp. 67-73 ◽  
Author(s):  
Paul M. A. Antony ◽  
Olga Boyd ◽  
Christophe Trefois ◽  
Wim Ammerlaan ◽  
Marek Ostaszewski ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane

scholarly journals Alpha-Tocotrienol Prevents Oxidative Stress-Mediated Post-Translational Cleavage of Bcl-xL in Primary Hippocampal Neurons

2019 ◽  
Vol 21 (1) ◽  
pp. 220 ◽  
Author(s):  
Han-A Park ◽  
Nelli Mnatsakanyan ◽  
Katheryn Broman ◽  
Abigail U. Davis ◽  
Jordan May ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Function ◽  
Hippocampal Neurons ◽  
Mitochondrial Membrane ◽  
Antioxidant Properties ◽  
B Cell Lymphoma ◽  
Atp Depletion ◽  
Primary Hippocampal Neurons

B-cell lymphoma-extra large (Bcl-xL) is an anti-apoptotic member of the Bcl2 family of proteins, which supports neurite outgrowth and neurotransmission by improving mitochondrial function. During excitotoxic stimulation, however, Bcl-xL undergoes post-translational cleavage to ∆N-Bcl-xL, and accumulation of ∆N-Bcl-xL causes mitochondrial dysfunction and neuronal death. In this study, we hypothesized that the generation of reactive oxygen species (ROS) during excitotoxicity leads to formation of ∆N-Bcl-xL. We further proposed that the application of an antioxidant with neuroprotective properties such as α-tocotrienol (TCT) will prevent ∆N-Bcl-xL-induced mitochondrial dysfunction via its antioxidant properties. Primary hippocampal neurons were treated with α-TCT, glutamate, or a combination of both. Glutamate challenge significantly increased cytosolic and mitochondrial ROS and ∆N-Bcl-xL levels. ∆N-Bcl-xL accumulation was accompanied by intracellular ATP depletion, loss of mitochondrial membrane potential, and cell death. α-TCT prevented loss of mitochondrial membrane potential in hippocampal neurons overexpressing ∆N-Bcl-xL, suggesting that ∆N-Bcl-xL caused the loss of mitochondrial function under excitotoxic conditions. Our data suggest that production of ROS is an important cause of ∆N-Bcl-xL formation and that preventing ROS production may be an effective strategy to prevent ∆N-Bcl-xL-mediated mitochondrial dysfunction and thus promote neuronal survival.

scholarly journals Energy transduction in intact synaptosomes. Influence of plasma-membrane depolarization on the respiration and membrane potential of internal mitochondria determined in situ

1980 ◽  
Vol 186 (1) ◽  
pp. 21-33 ◽  
Author(s):  
I D Scott ◽  
D G Nicholls
Keyword(s):  
Plasma Membrane ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Significant Proportion ◽  
Membrane Potentials ◽  
Simultaneous Estimation ◽  
Anaerobic Glycolysis ◽  
Mitochondrial Potential ◽  
Plasma Membrane Potential

A method is described, based on the differential accumulation of Rb+ and methyltriphenylphosphonium, for the simultaneous estimation of the membrane potentials across the plasma membrane of isolated nerve endings (synaptosomes), and across the inner membrane of mitochondria within the synaptosomal cytoplasm. These determinations, together with measurements of respiratory rates, and ATP and phosphocreatine concentrations, are used to define the bioenergetic behaviour of isolated synaptosomes under a variety of conditions. Under control conditions, in the presence of glucose, the plasma and mitochondrial membrane potentials are respectively 45 and 148mV. Addition of a proton translocator induces a 5-fold increase in respiration, and abolishes the mitochondrial membrane potential. The addition of rotenone to inhibit respiration does not affect the plasma membrane potential, and only lowers the mitochondrial membrane potential to 128mV. Evidence is presented that ATP synthesis by anaerobic glycolysis is sufficient under these conditions to maintain ATP-dependent processes, including the reversal of the mitochondrial ATP synthetase. Addition of oligomycin under non-respiring conditions leads to a complete collapse of the mitochondrial potential. Even under control conditions the plasma membrane (Na+ + K+)-dependent ATPase is responsible for a significant proportion of the synaptosomal ATP turnover. Veratridine greatly increases respiration, and depolarizes the plasma membrane, but only slightly lowers the mitochondrial membrane potential. High K+ and ouabain also lower the plasma membrane potential without decreasing the mitochondrial membrane potential. In non-respiring synaptosomes, anaerobic glycolysis is incapable of maintaining cytosolic ATP during the increased turnover induced by veratridine, and the mitochondrial membrane potential collapses. It is concluded that the internal mitochondria must be considered in any study of synaptosomal transport.

Exogenous L-carnitine a meliorated burn-induced cellular and mitochondrial injuries of hepatocytes via recovering CPT1 activity

2021 ◽  
Author(s):  
Pengtao Li ◽  
Zhengguo Xia ◽  
Weichang Kong ◽  
Qiong Wang ◽  
Ziyue Zhao ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Membrane Potential ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Membrane Potential ◽  
Differentially Expressed Genes ◽  
Liver Tissue ◽  
Mitochondrial Membrane ◽  
Cellular Fatty Acid ◽  
Burn Patients ◽  
Severe Burn

Abstract Background : Impaired liver fatty acid metabolism and persistent mitochondrial dysfunction are common phenomena and associated with liver failure. Decreased serum L-carnitine, a vitamin involved in fatty-acid and energy metabolisms, has been reported in severe burn patients. The current research aimed to study the effects and mechanism of L-carnitine on mitochondrial damage and other hepatocytic injuries. Methods : Serum carnitine and indicators for hepatocytic injuries including AST, ALT, LDH, TG and OCT in severe burn patients and healthy controls were analyzed. The burn model in rats was established by skin scalding, and the carnitine was administered to the rats. The indicators mentioned above in the serum, and oil red staining, TUNEL staining and TEM observation, mitochondrial membrane potential, and CPT1 activity as well as CPT1 expression of the liver tissue were examined. HepG2 cells, treated with the CPT1 inhibitor etomoxir, were supplied with/without carnitine for 24h. The indicators mentioned above were examined, and apoptotic cells were analyzed by flow cytometry. Transcriptom high throughput sequencing of the rat liver tissues was performed, and differentially expressed genes Fabp4, Acacb, Acsm5 and Pnpla3 were further determined by RT-qPCR. Results : Significantly decreased carnitine and increased AST, ALT, LDH and OCT in the serum were detected in the severe burn patients and the scalded rats. Accumulation of TG, obvious mitochondrial shrinking, altered mitochondrial membrane potential, decreased ketogenesis and declined CPT1 activity were found in the liver tissue of the scalded rats. Administration of carnitine recovered CPT1 activity and improved all the parameters for cellular, fatty acid metabolic and mitochondrial injuries. Inhibition of CPT1 activity with etomoxir in vitro induced similar hepatocytic injuries found in the burn patients and the scalded rats, and supplementation of carnitine restored CPT1 activity and ameliorated these injuries. Differentially expressed genes Fabp4, Acacb, Acsm5 and Pnpla3 in the liver tissue and in the etomoxir-treated hepatocytes were also restored by exogenous carnitine. Conclusion : Exogenous carnitine exerts its protective effect on severe burn-induced cellular, fatty-acid metabolic and mitochondrial dysfunction of the hepatocytes via restore of CPT1 activity.

NAD+ deficiency and mitochondrial dysfunction in granulosa cells of women with polycystic ovary syndrome‡

2021 ◽  
Author(s):  
Yujiao Wang ◽  
Qingling Yang ◽  
Huan Wang ◽  
Jing Zhu ◽  
Luping Cong ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Polycystic Ovary Syndrome ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Membrane Potential ◽  
Granulosa Cells ◽  
Mitochondrial Membrane ◽  
Polycystic Ovary ◽  
Tumor Cell Line ◽  
Ovary Syndrome ◽  
Atp Generation

Abstract Polycystic ovary syndrome (PCOS) is a prevalent heterogeneous endocrine disorder characterized by ovulation dysfunction, androgen excess, ovarian polycystic changes, insulin resistance, and infertility. Although underlying mechanisms for PCOS are still unknown, inflammation and mitochondrial dysfunction in granulosa cells (GCs) of PCOS patients have been reported. Here, we found that Nicotinamide Adenine Dinucleotide (NAD+) levels in GCs of PCOS patients was significantly decreased when compared with controls. Also, we found that higher expression of inflammation factors, increased reactive oxygen species (ROS) accumulation, lower adenosine triphosphate (ATP) generation, and decreased mitochondrial membrane potential, as well as abnormal mitochondrial dynamics in GCs of PCOS patients. In addition, the NAD+ levels were decreased after activation of inflammation in human granulosa-like tumor cell line (KGN) treated by Lipopolysaccharide (LPS). However, supplementation of nicotinamide riboside (NR), a NAD+ precursor, could largely restore the NAD+ content, reduce ROS levels and improve mitochondrial function demonstrated by increased mitochondrial membrane potential and ATP generation in LPS-treated KGN cells. Our data suggested that inflammation decreased NAD+ levels in GCs of PCOS patients, while supplementation of NR could restore NAD+ levels and alleviated mitochondrial dysfunction in GCs of PCOS patients.

scholarly journals Mitochondrial dysfunction in antiphospholipid syndrome: implications in the pathogenesis of the disease and effects of coenzyme Q10 treatment

Blood ◽  
2012 ◽  
Vol 119 (24) ◽  
pp. 5859-5870 ◽  
Author(s):  
Carlos Perez-Sanchez ◽  
Patricia Ruiz-Limon ◽  
Maria Angeles Aguirre ◽  
Maria Laura Bertolaccini ◽  
Munther A. Khamashta ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Membrane Potential ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Membrane Potential ◽  
Antiphospholipid Syndrome ◽  
Coenzyme Q10 ◽  
Mitochondrial Membrane ◽  
Antiphospholipid Antibody ◽  
Antibody Treatment

Abstract The exact mechanisms underlying the role of oxidative stress in the pathogenesis and the prothrombotic or proinflammatory status of antiphospholipid syndrome (APS) remain unknown. Here, we investigate the role of oxidative stress and mitochondrial dysfunction in the proatherothrombotic status of APS patients induced by IgG-antiphospholipid antibodies and the beneficial effects of supplementing cells with coenzyme Q10 (CoQ10). A significant increase in relevant prothrombotic and inflammatory parameters in 43 APS patients was found compared with 38 healthy donors. Increased peroxide production, nuclear abundance of Nrf2, antioxidant enzymatic activity, decreased intracellular glutathione, and altered mitochondrial membrane potential were found in monocytes and neutrophils from APS patients. Accelerated atherosclerosis in APS patients was found associated with their inflammatory or oxidative status. CoQ10 preincubation of healthy monocytes before IgG-antiphospholipid antibody treatment decreased oxidative stress, the percentage of cells with altered mitochondrial membrane potential, and the induced expression of tissue factor, VEGF, and Flt1. In addition, CoQ10 significantly improved the ultrastructural preservation of mitochondria and prevented IgG-APS–induced fission mediated by Drp-1 and Fis-1 proteins. In conclusion, the oxidative perturbation in APS patient leukocytes, which is directly related to an inflammatory and pro-atherothrombotic status, relies on alterations in mitochondrial dynamics and metabolism that may be prevented, reverted, or both by treatment with CoQ10.

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