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 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 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 Genetic Mutations and Mitochondrial Toxins Shed New Light on the Pathogenesis of Parkinson's Disease

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Shigeto Sato ◽  
Nobutaka Hattori
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Mitochondrial Dysfunction ◽  
Cultured Cells ◽  
Cellular Functions ◽  
Carbonyl Cyanide ◽  
Mitochondrial Toxins ◽  
Cellular Abnormalities ◽  
Mitochondrial Uncoupler

The cellular abnormalities in Parkinson's disease (PD) include mitochondrial dysfunction and oxidative damage, which are probably induced by both genetic predisposition and environmental factors. Mitochondrial dysfunction has long been implicated in the pathogenesis of PD. The recent discovery of genes associated with the etiology of familial PD has emphasized the role of mitochondrial dysfunction in PD. The discovery and increasing knowledge of the function of PINK1 and parkin, which are associated with the mitochondria, have also enhanced the understanding of cellular functions. The PINK1-parkin pathway is associated with quality control of the mitochondria, as determined in cultured cells treated with the mitochondrial uncoupler carbonyl cyanide m-chlorophenylhydrazone (CCCP), which causes mitochondrial depolarization. To date, the use of mitochondrial toxins, for example, 1-methyl-4-phynyl-tetrahydropyridine (MPTP) and CCCP, has contributed to our understanding of PD. We review how these toxins and familial PD gene products are associated with and have enhanced our understanding of the role of mitochondrial dysfunction in PD.

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.

Monitoring of mitochondrial membrane potential in isolated perfused rat heart

1984 ◽  
Vol 247 (4) ◽  
pp. H508-H516
Author(s):  
R. A. Kauppinen ◽  
I. E. Hassinen
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Optical Methods ◽  
Perfused Heart ◽  
Rat Hearts ◽  
Carbonyl Cyanide ◽  
Perfused Rat Hearts ◽  
Beating Rate ◽  
Isolated Perfused Rat Hearts

Optical methods were tested for measuring the membrane potential changes of mitochondria in isolated perfused rat hearts. Safranin was found to be rapidly taken up by the Langendorff-perfused heart, and after loading with the dye there was practically no washout of the stain during perfusion with Krebs-Ringer bicarbonate solution. Staining with safranin induced the appearance of an intense absorption band in the reflectance spectrum of the heart, but the absorbance spectrum changes were not useful for monitoring the mitochondrial membrane potential changes because of interference by endogenous hemoproteins. The fluorescence intensity, however, responded in a manner which indicated that its changes originated from dye attached to the mitochondria. A decrease of the fluorescence was found on energizing the mitochondria by decreasing the cellular energy consumption by arrest induced by 18 mM K+ or by decreasing the beating rate of an electrically paced heart from 5 Hz to the endogenous ventricular frequency of 1.5 Hz. In hearts arrested by Ca2+ depletion, 18 mM K+ did not affect the safranin fluorescence. This was taken to indicate that under these conditions the safranin fluorescence was not sensitive to the plasma membrane potential. The uncoupler carbonyl cyanide m-chlorophenylhydrazone induced an intense enhancement of safranin fluorescence in the perfused heart, demonstrating that the probe is sensitive to mitochondrial membrane potential.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

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