Affiliation:
1. Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
2. Department of Pathology and Oncology, Juntendo University School of Medicine, Tokyo 113-8412, Japan
Abstract
Abstract
Mitochondrial DNA (mtDNA) replication is tightly regulated and necessary for cellular homeostasis; however, its relationship with mitochondrial metabolism remains unclear. Advances in metabolomics integrated with the rapid isolation of mitochondria will allow for remarkable progress in analyzing mitochondrial metabolism. Here, we propose a novel methodology for mitochondria-targeted metabolomics, which employs a quick isolation procedure using a hemolytic toxin from Streptococcus pyogenes streptolysin O (SLO). SLO isolation of mitochondria from cultured HEK293 cells is time- and labor-saving for simultaneous multi-sample processing and has been applied to various other cell lines in this study. Furthermore, our method can detect the time-dependent reduction in mitochondrial ATP in response to a glycolytic inhibitor 2-deoxyglucose, indicating the suitability to prepare metabolite analysis–competent mitochondria. Using this methodology, we searched for specific mitochondrial metabolites associated with mtDNA replication activation, and nucleotides and NAD+ were identified to be prominently altered. Most notably, treatment of β-nicotinamide mononucleotide (β-NMN), a precursor of NAD+, to HEK293 cells activated and improved the rate of mtDNA replication by increasing nucleotides in mitochondria and decreasing their degradation products: nucleosides. Our results suggest that β-NMN metabolism plays a role in supporting mtDNA replication by maintaining the nucleotide pool balance in the mitochondria.
Publisher
Oxford University Press (OUP)
Subject
Molecular Biology,Biochemistry,General Medicine
Cited by
4 articles.
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