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Selective NADH communication from α-ketoglutarate dehydrogenase to mitochondrial transhydrogenase prevents reactive oxygen species formation under reducing conditions in the heart
In heart failure, a functional block of complex I of the respiratory chain provokes superoxide generation, which is transformed to H(2)O(2) by dismutation. The Krebs cycle produces NADH, which delivers electrons to complex I, and NADPH for H(2)O(2) elimination via isocitrate dehydrogenase and nicoti...
Autores principales: | , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Springer Berlin Heidelberg
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7399685/ https://www.ncbi.nlm.nih.gov/pubmed/32748289 http://dx.doi.org/10.1007/s00395-020-0815-1 |
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author | Wagner, Michael Bertero, Edoardo Nickel, Alexander Kohlhaas, Michael Gibson, Gary E. Heggermont, Ward Heymans, Stephane Maack, Christoph |
author_facet | Wagner, Michael Bertero, Edoardo Nickel, Alexander Kohlhaas, Michael Gibson, Gary E. Heggermont, Ward Heymans, Stephane Maack, Christoph |
author_sort | Wagner, Michael |
collection | PubMed |
description | In heart failure, a functional block of complex I of the respiratory chain provokes superoxide generation, which is transformed to H(2)O(2) by dismutation. The Krebs cycle produces NADH, which delivers electrons to complex I, and NADPH for H(2)O(2) elimination via isocitrate dehydrogenase and nicotinamide nucleotide transhydrogenase (NNT). At high NADH levels, α-ketoglutarate dehydrogenase (α-KGDH) is a major source of superoxide in skeletal muscle mitochondria with low NNT activity. Here, we analyzed how α-KGDH and NNT control H(2)O(2) emission in cardiac mitochondria. In cardiac mitochondria from NNT-competent BL/6N mice, H(2)O(2) emission is equally low with pyruvate/malate (P/M) or α-ketoglutarate (α-KG) as substrates. Complex I inhibition with rotenone increases H(2)O(2) emission from P/M, but not α-KG respiring mitochondria, which is potentiated by depleting H(2)O(2)-eliminating capacity. Conversely, in NNT-deficient BL/6J mitochondria, H(2)O(2) emission is higher with α-KG than with P/M as substrate, and further potentiated by complex I blockade. Prior depletion of H(2)O(2)-eliminating capacity increases H(2)O(2) emission from P/M, but not α-KG respiring mitochondria. In cardiac myocytes, downregulation of α-KGDH activity impaired dynamic mitochondrial redox adaptation during workload transitions, without increasing H(2)O(2) emission. In conclusion, NADH from α-KGDH selectively shuttles to NNT for NADPH formation rather than to complex I of the respiratory chain for ATP production. Therefore, α-KGDH plays a key role for H(2)O(2) elimination, but is not a relevant source of superoxide in heart. In heart failure, α-KGDH/NNT-dependent NADPH formation ameliorates oxidative stress imposed by complex I blockade. Downregulation of α-KGDH may, therefore, predispose to oxidative stress in heart failure. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s00395-020-0815-1) contains supplementary material, which is available to authorized users. |
format | Online Article Text |
id | pubmed-7399685 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | Springer Berlin Heidelberg |
record_format | MEDLINE/PubMed |
spelling | pubmed-73996852020-08-13 Selective NADH communication from α-ketoglutarate dehydrogenase to mitochondrial transhydrogenase prevents reactive oxygen species formation under reducing conditions in the heart Wagner, Michael Bertero, Edoardo Nickel, Alexander Kohlhaas, Michael Gibson, Gary E. Heggermont, Ward Heymans, Stephane Maack, Christoph Basic Res Cardiol Original Contribution In heart failure, a functional block of complex I of the respiratory chain provokes superoxide generation, which is transformed to H(2)O(2) by dismutation. The Krebs cycle produces NADH, which delivers electrons to complex I, and NADPH for H(2)O(2) elimination via isocitrate dehydrogenase and nicotinamide nucleotide transhydrogenase (NNT). At high NADH levels, α-ketoglutarate dehydrogenase (α-KGDH) is a major source of superoxide in skeletal muscle mitochondria with low NNT activity. Here, we analyzed how α-KGDH and NNT control H(2)O(2) emission in cardiac mitochondria. In cardiac mitochondria from NNT-competent BL/6N mice, H(2)O(2) emission is equally low with pyruvate/malate (P/M) or α-ketoglutarate (α-KG) as substrates. Complex I inhibition with rotenone increases H(2)O(2) emission from P/M, but not α-KG respiring mitochondria, which is potentiated by depleting H(2)O(2)-eliminating capacity. Conversely, in NNT-deficient BL/6J mitochondria, H(2)O(2) emission is higher with α-KG than with P/M as substrate, and further potentiated by complex I blockade. Prior depletion of H(2)O(2)-eliminating capacity increases H(2)O(2) emission from P/M, but not α-KG respiring mitochondria. In cardiac myocytes, downregulation of α-KGDH activity impaired dynamic mitochondrial redox adaptation during workload transitions, without increasing H(2)O(2) emission. In conclusion, NADH from α-KGDH selectively shuttles to NNT for NADPH formation rather than to complex I of the respiratory chain for ATP production. Therefore, α-KGDH plays a key role for H(2)O(2) elimination, but is not a relevant source of superoxide in heart. In heart failure, α-KGDH/NNT-dependent NADPH formation ameliorates oxidative stress imposed by complex I blockade. Downregulation of α-KGDH may, therefore, predispose to oxidative stress in heart failure. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s00395-020-0815-1) contains supplementary material, which is available to authorized users. Springer Berlin Heidelberg 2020-08-03 2020 /pmc/articles/PMC7399685/ /pubmed/32748289 http://dx.doi.org/10.1007/s00395-020-0815-1 Text en © The Author(s) 2020 Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. |
spellingShingle | Original Contribution Wagner, Michael Bertero, Edoardo Nickel, Alexander Kohlhaas, Michael Gibson, Gary E. Heggermont, Ward Heymans, Stephane Maack, Christoph Selective NADH communication from α-ketoglutarate dehydrogenase to mitochondrial transhydrogenase prevents reactive oxygen species formation under reducing conditions in the heart |
title | Selective NADH communication from α-ketoglutarate dehydrogenase to mitochondrial transhydrogenase prevents reactive oxygen species formation under reducing conditions in the heart |
title_full | Selective NADH communication from α-ketoglutarate dehydrogenase to mitochondrial transhydrogenase prevents reactive oxygen species formation under reducing conditions in the heart |
title_fullStr | Selective NADH communication from α-ketoglutarate dehydrogenase to mitochondrial transhydrogenase prevents reactive oxygen species formation under reducing conditions in the heart |
title_full_unstemmed | Selective NADH communication from α-ketoglutarate dehydrogenase to mitochondrial transhydrogenase prevents reactive oxygen species formation under reducing conditions in the heart |
title_short | Selective NADH communication from α-ketoglutarate dehydrogenase to mitochondrial transhydrogenase prevents reactive oxygen species formation under reducing conditions in the heart |
title_sort | selective nadh communication from α-ketoglutarate dehydrogenase to mitochondrial transhydrogenase prevents reactive oxygen species formation under reducing conditions in the heart |
topic | Original Contribution |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7399685/ https://www.ncbi.nlm.nih.gov/pubmed/32748289 http://dx.doi.org/10.1007/s00395-020-0815-1 |
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