MitoTALEN reduces mutant mtDNA load and restores tRNAAla levels in a mouse model of heteroplasmic mtDNA mutation


Mutations in the mitochondrial DNA (mtDNA) are responsible for several metabolic disorders, commonly involving muscle and the central nervous system1. Because of the critical role of mtDNA in oxidative phosphorylation, the majority of pathogenic mtDNA mutations are heteroplasmic, co-existing with wild-type molecules1. Using a mouse model with a heteroplasmic mtDNA mutation2, we tested whether mitochondrial-targeted TALENs (mitoTALENs)3,4 could reduce the mutant mtDNA load in muscle and heart. AAV9-mitoTALEN was administered via intramuscular, intravenous, and intraperitoneal injections. Muscle and heart were efficiently transduced and showed a robust reduction in mutant mtDNA, which was stable over time. The molecular defect, namely a decrease in transfer RNAAla levels, was restored by the treatment. These results showed that mitoTALENs, when expressed in affected tissues, could revert disease-related phenotypes in mice.

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Fig. 1: Development of a mitoTALEN for the mouse mutant m.5024C>T mtDNA.
Fig. 2: AAV9-MitoTALEN is expressed in skeletal muscle and shifts mtDNA heteroplasmy in a predicted manner.
Fig. 3: AAV9-mitoTALENs induce a significant and persistent shift in mtDNA heteroplasmy in heart and skeletal muscle after systemic injection.

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All the data contained in this manuscript is available to investigators.

Change history

  • 05 October 2018

    In the version of this article originally published, there was an error in Fig. 1a. The m.5024C>T mutation, shown as a green T, was displaced by one base. The error has been corrected in the print, HTML and PDF versions of this article.


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This work was supported primarily by the National Institutes of Health Grant 5R01EY010804, with additional support from 1R01AG036871 and 1R01NS079965 (NIH) and the Muscular Dystrophy Association (CTM). We also acknowledge support from The JDM Fund for Mitochondrial Research and the Biscardi family. N.N. is supported by an American Heart Association predoctoral fellowship (16PRE30480009). We are grateful to the University of Miami Flow Cytometry core facility (SCCC) for expert assistance.

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S.R.B. was involved with the concept, design and execution of the cell and mouse experiments, and wrote and revised the manuscript. J.H.K.K. characterized the mouse model and the tRNA alanine northern experiments. C.V.P. produced and characterized the cell lines with high levels of the m.5024C>T mtDNA mutation. N.N. performed the experiments with mouse and the detection of mtDNA deletions. M.M. performed the tRNA alanine northern experiments. M.P. prepared the positive controls for mtDNA deletions. S.L.W. was involved with the concept, troubleshooting and recombinant virus administration. N.-G.L. characterized the mouse model. J.B.S. characterized the mouse model and the tRNA alanine northern experiments. C.T.M. was involved with the concept and design, and also wrote and revised the manuscript. All authors read and edited the manuscript.

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Correspondence to Sandra R. Bacman or Carlos T. Moraes.

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Bacman, S.R., Kauppila, J.H.K., Pereira, C.V. et al. MitoTALEN reduces mutant mtDNA load and restores tRNAAla levels in a mouse model of heteroplasmic mtDNA mutation. Nat Med 24, 1696–1700 (2018).

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