Lactate dehydrogenase supports lactate oxidation in mitochondria isolated from different mouse tissues

• Published in: Redox biology 2020-01, Vol.28, p.101339-101339, Article 101339
• Main Authors: Young, Adrian, Oldford, Catherine, Mailloux, Ryan J.
• Format: Article
• Language: English
• Subjects: Animals; Cell Respiration; L-Lactate Dehydrogenase - metabolism; Lactic Acid - metabolism; Mice; Mitochondria - metabolism; Mitochondria, Liver - metabolism; Mitochondria, Muscle - metabolism; Models, Biological; Organ Specificity; Oxidation-Reduction; Short Communication
• ISSN: 2213-2317; 2213-2317
• DOI: 10.1016/j.redox.2019.101339

Research over the past seventy years has established that mitochondrial-l-lactate dehydrogenase (m-L-LDH) is vital for mitochondrial bioenergetics. However, in recent report, Fulghum et al. concluded that lactate is a poor fuel for mitochondrial respiration [1]. In the present study, we have followed up on these findings and conducted an independent investigation to determine if lactate can support mitochondrial bioenergetics. We demonstrate herein that lactate can fuel the bioenergetics of heart, muscle, and liver mitochondria. Lactate was just as effective as pyruvate at stimulating mitochondrial coupling efficiency. Inclusion of LDH (sodium oxamate or GSK 2837808A) and pyruvate dehydrogenase (PDH; CPI-613) inhibitors abolished respiration in mitochondria energized with lactate. Lactate also fueled mitochondrial ROS generation and was just as effective as pyruvate at stimulating H2O2 production. Additionally, lactate-induced ROS production was inhibited by both LDH and PDH inhibitors. Enzyme activity measurements conducted on permeabilized mitochondria revealed that LDH is localized in mitochondria. In aggregate, we can conclude that mitochondrial LDH fuels bioenergetics in several tissues by oxidizing lactate. [Display omitted] •Lactate can fuel mitochondrial respiration.•Lactate serves as a substrate for H2O2 production.•Mitochondria contain LDH.