The Charcot–Marie Tooth Disease Mutation R94Q in MFN2 Decreases ATP Production but Increases Mitochondrial Respiration under Conditions of Mild Oxidative Stress
Charcot−Marie tooth disease is a hereditary polyneuropathy caused by mutations in Mitofusin-2 (MFN2), a GTPase in the outer mitochondrial membrane involved in the regulation of mitochondrial fusion and bioenergetics. Autosomal-dominant inheritance of a R94Q mutation in MFN2 causes the axon...
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MDPI AG
2019-10-01
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| author | Christina Wolf Rahel Zimmermann Osamah Thaher Diones Bueno Verena Wüllner Michael K.E. Schäfer Philipp Albrecht Axel Methner |
| author_facet | Christina Wolf Rahel Zimmermann Osamah Thaher Diones Bueno Verena Wüllner Michael K.E. Schäfer Philipp Albrecht Axel Methner |
| author_sort | Christina Wolf |
| collection | DOAJ |
| description | Charcot−Marie tooth disease is a hereditary polyneuropathy caused by mutations in Mitofusin-2 (MFN2), a GTPase in the outer mitochondrial membrane involved in the regulation of mitochondrial fusion and bioenergetics. Autosomal-dominant inheritance of a R94Q mutation in MFN2 causes the axonal subtype 2A2A which is characterized by early onset and progressive atrophy of distal muscles caused by motoneuronal degeneration. Here, we studied mitochondrial shape, respiration, cytosolic, and mitochondrial ATP content as well as mitochondrial quality control in MFN2-deficient fibroblasts stably expressing wildtype or R94Q MFN2. Under normal culture conditions, R94Q cells had slightly more fragmented mitochondria but a similar mitochondrial oxygen consumption, membrane potential, and ATP production as wildtype cells. However, when inducing mild oxidative stress 24 h before analysis using 100 µM hydrogen peroxide, R94Q cells exhibited significantly increased respiration but decreased mitochondrial ATP production. This was accompanied by increased glucose uptake and an up-regulation of hexokinase 1 and pyruvate kinase M2, suggesting increased pyruvate shuttling into mitochondria. Interestingly, these changes coincided with decreased levels of PINK1/Parkin-mediated mitophagy in R94Q cells. We conclude that mitochondria harboring the disease-causing R94Q mutation in MFN2 are more susceptible to oxidative stress, which causes uncoupling of respiration and ATP production possibly by a less efficient mitochondrial quality control. |
| first_indexed | 2024-03-12T09:20:20Z |
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| issn | 2073-4409 |
| language | English |
| last_indexed | 2024-03-12T09:20:20Z |
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| spelling | doaj.art-94d43432897b444986c8665715e6fe262023-09-02T14:32:22ZengMDPI AGCells2073-44092019-10-01810128910.3390/cells8101289cells8101289The Charcot–Marie Tooth Disease Mutation R94Q in MFN2 Decreases ATP Production but Increases Mitochondrial Respiration under Conditions of Mild Oxidative StressChristina Wolf0Rahel Zimmermann1Osamah Thaher2Diones Bueno3Verena Wüllner4Michael K.E. Schäfer5Philipp Albrecht6Axel Methner7Institute of Molecular Medicine, University Medical Center, Johannes Gutenberg-Universität Mainz, 55131 Mainz, GermanyInstitute of Molecular Medicine, University Medical Center, Johannes Gutenberg-Universität Mainz, 55131 Mainz, GermanyInstitute of Molecular Medicine, University Medical Center, Johannes Gutenberg-Universität Mainz, 55131 Mainz, GermanyInstitute of Molecular Medicine, University Medical Center, Johannes Gutenberg-Universität Mainz, 55131 Mainz, GermanyInstitute of Molecular Medicine, University Medical Center, Johannes Gutenberg-Universität Mainz, 55131 Mainz, GermanyDepartment of Anesthesiology, Research Center for Immunotherapy (FZI), Focus Program Translational Neurosciences (FTN), University Medical Center, Johannes Gutenberg-Universität Mainz, 55116 Mainz, GermanyDepartment of Neurology, University Hospital Düsseldorf, 40210 Düsseldorf, GermanyInstitute of Molecular Medicine, University Medical Center, Johannes Gutenberg-Universität Mainz, 55131 Mainz, GermanyCharcot−Marie tooth disease is a hereditary polyneuropathy caused by mutations in Mitofusin-2 (MFN2), a GTPase in the outer mitochondrial membrane involved in the regulation of mitochondrial fusion and bioenergetics. Autosomal-dominant inheritance of a R94Q mutation in MFN2 causes the axonal subtype 2A2A which is characterized by early onset and progressive atrophy of distal muscles caused by motoneuronal degeneration. Here, we studied mitochondrial shape, respiration, cytosolic, and mitochondrial ATP content as well as mitochondrial quality control in MFN2-deficient fibroblasts stably expressing wildtype or R94Q MFN2. Under normal culture conditions, R94Q cells had slightly more fragmented mitochondria but a similar mitochondrial oxygen consumption, membrane potential, and ATP production as wildtype cells. However, when inducing mild oxidative stress 24 h before analysis using 100 µM hydrogen peroxide, R94Q cells exhibited significantly increased respiration but decreased mitochondrial ATP production. This was accompanied by increased glucose uptake and an up-regulation of hexokinase 1 and pyruvate kinase M2, suggesting increased pyruvate shuttling into mitochondria. Interestingly, these changes coincided with decreased levels of PINK1/Parkin-mediated mitophagy in R94Q cells. We conclude that mitochondria harboring the disease-causing R94Q mutation in MFN2 are more susceptible to oxidative stress, which causes uncoupling of respiration and ATP production possibly by a less efficient mitochondrial quality control.https://www.mdpi.com/2073-4409/8/10/1289oxidative stressmfn2mitochondriafusion/fission |
| spellingShingle | Christina Wolf Rahel Zimmermann Osamah Thaher Diones Bueno Verena Wüllner Michael K.E. Schäfer Philipp Albrecht Axel Methner The Charcot–Marie Tooth Disease Mutation R94Q in MFN2 Decreases ATP Production but Increases Mitochondrial Respiration under Conditions of Mild Oxidative Stress Cells oxidative stress mfn2 mitochondria fusion/fission |
| title | The Charcot–Marie Tooth Disease Mutation R94Q in MFN2 Decreases ATP Production but Increases Mitochondrial Respiration under Conditions of Mild Oxidative Stress |
| title_full | The Charcot–Marie Tooth Disease Mutation R94Q in MFN2 Decreases ATP Production but Increases Mitochondrial Respiration under Conditions of Mild Oxidative Stress |
| title_fullStr | The Charcot–Marie Tooth Disease Mutation R94Q in MFN2 Decreases ATP Production but Increases Mitochondrial Respiration under Conditions of Mild Oxidative Stress |
| title_full_unstemmed | The Charcot–Marie Tooth Disease Mutation R94Q in MFN2 Decreases ATP Production but Increases Mitochondrial Respiration under Conditions of Mild Oxidative Stress |
| title_short | The Charcot–Marie Tooth Disease Mutation R94Q in MFN2 Decreases ATP Production but Increases Mitochondrial Respiration under Conditions of Mild Oxidative Stress |
| title_sort | charcot marie tooth disease mutation r94q in mfn2 decreases atp production but increases mitochondrial respiration under conditions of mild oxidative stress |
| topic | oxidative stress mfn2 mitochondria fusion/fission |
| url | https://www.mdpi.com/2073-4409/8/10/1289 |
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