Just like the genomes in the nuclei of our cells, these energy-generating structures have their own set of DNA, which is a proxy measure for mitochondrial function and has been associated with several aging-related diseases.
Our cells contain more than one set of DNA: one in our nucleus encodes most cellular processes and another in the energy-generating structure of the cell known as the mitochondria. Just like the DNA in the nuclei of every cell, the replication and integrity of mitochondrial DNA (mtDNA) is critical for cells to function and flourish and for us to fulfill a healthy and long life. But we have a lot to learn about the link between mtDNA and mitochondrial function in the context of aging and longevity. Doing so can enable us to bolster the activity of this crucial cell structure and integrity of its separate genetic hard drive for improving healthspan and lifespan.
Kang and colleagues from Kyushu University in Japan reported in the Journal of Biochemistry that nicotinamide mononucleotide (NMN) enhances mtDNA replication. The researchers, who wrote on behalf of the Japanese Biochemical Society, found that treating human kidney cells with NMN activated and increased the rate of mtDNA replication by increasing the number of building blocks of DNA (nucleotides) in mitochondria while decreasing their degradation products (nucleosides). These findings suggest a mechanism for how NMN benefits mitochondria, metabolism, and, ultimately, aging.