Advancing Mitochondrial Disease Treatment with Base Editing

Researchers from UMC Utrecht in the Netherlands have made progress toward effective treatments for mitochondrial diseases by using a base editor to correct harmful mutations in mitochondrial DNA. Their findings, published in PLOS Biology, demonstrate the potential of this approach for people affected by rare genetic conditions.

Mitochondria, known as the cell’s powerhouses, possess their own distinct DNA. Mutations in this DNA can cause a variety of maternally inherited diseases, as well as contribute to cancer and aging-related disorders. Although CRISPR technology has enabled correction of mutations in nuclear DNA, it has not been effective for mitochondrial DNA due to its inability to cross the mitochondrial membrane.

In this study, the team utilized a specific base editor called DdCBE (double-stranded DNA deaminase toxin A-derived cytosine base editor). This tool enables targeted changes to a single DNA letter without cutting the DNA and is capable of editing mitochondrial DNA. The researchers demonstrated that they could both introduce and correct mitochondrial DNA mutations in various disease-related cell types in the laboratory. For example, they engineered liver cells with a mutation that disrupts energy production and successfully repaired a different mutation in skin cells from a patient with Gitelman-like syndrome, restoring important aspects of mitochondrial function.

To help advance their technique into clinical use, the researchers tested delivering the base editors as mRNA within lipid nanoparticles. This method proved more efficient and less toxic than previous approaches using DNA plasmids. The edits were highly specific, with minimal off-target effects in nuclear DNA and multiple edits detected in mitochondrial DNA.

According to the team, “The potential of mitochondrial base editing in disease modeling and potential therapeutic interventions makes it a promising avenue for future research and development in mitochondrial medicine.”