Mitochondrial genome editing reveals the impact of complex I heteroplasmic variants on human neurogenesis
- 1Department of General Pediatrics, Neonatology and Pediatric Cardiology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf
Abstract
Mitochondrial DNA (mtDNA) variants, whether maternally inherited or acquired somatically during aging, can be particularly detrimental to cells that rely on mitochondrial metabolism such as neurons. The functional consequences of mtDNA variants are thought to depend on their heteroplasmy, defined as the proportion of mtDNA molecules carrying that variant. However, investigating the specific effects of heteroplasmic mtDNA variants on human neuronal function has been challenging. Studies using patient-derived cells cannot conclusively attribute observed phenotypes to a single mtDNA variant, while conventional genome editing approaches are not applicable to mtDNA. Here, we use DddA-derived cytosine base editor (DdCBE) to introduce pathogenic heteroplasmic mtDNA variants into Neurogenin 2 (NGN2)-inducible human induced pluripotent stem cells (iPSCs). We focus on two variants in the genes MT-ND1 and MT-ND5 belonging to complex I (CI), the largest component of the mitochondrial respiratory chain and a frequent contributor to human disease, including the incurable neurodevelopmental disorder Leigh syndrome. mtDNA-edited iPSC lines exhibit low off-target editing and maintain similar heteroplasmy following subclonal isolation and differentiation into NGN2-induced neurons (iNs). Although the CI variants do not substantially affect mitochondrial energy metabolism in undifferentiated iPSCs, they reduce mitochondrial membrane potential in iNs where they drive a transcriptional reprogramming indicative of impaired neuronal commitment. These findings suggest that heteroplasmic CI variants are sufficient to disrupt neural fate specification even at relatively low heteroplasmy. More broadly, mtDNA editing in human iPSCs provides a powerful platform to investigate how mitochondrial fitness and heteroplasmy influence development and disease.
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BibTeX
@misc{tolle2026mitochondrial,
title = {{Mitochondrial genome editing reveals the impact of complex I heteroplasmic variants on human neurogenesis}},
author = {I. Tolle and C. Fiorini and J. Dobner and A. Zink and A. P. Pasti and V. Balmaceda and F. Tschuschke and D. Herebian and E. Mayatepek and E. Bottani and P. Lisowski and V. Carelli and A. Rossi and A. Prigione},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.28.762518},
url = {https://www.biorxiv.org/content/10.64898/2026.10.28.762518v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Mitochondrial genome editing reveals the impact of complex I heteroplasmic variants on human neurogenesis
AU - I. Tolle
AU - C. Fiorini
AU - J. Dobner
AU - A. Zink
AU - A. P. Pasti
AU - V. Balmaceda
AU - F. Tschuschke
AU - D. Herebian
AU - E. Mayatepek
AU - E. Bottani
AU - P. Lisowski
AU - V. Carelli
AU - A. Rossi
AU - A. Prigione
PY - 2026
DA - 2026/10/28
PB - bioRxiv
DO - 10.64898/2026.10.28.762518
UR - https://www.biorxiv.org/content/10.64898/2026.10.28.762518v1
AB - Mitochondrial DNA (mtDNA) variants, whether maternally inherited or acquired somatically during aging, can be particularly detrimental to cells that rely on mitochondrial metabolism such as neurons. The functional consequences of mtDNA variants are thought to depend on their heteroplasmy, defined as the proportion of mtDNA molecules carrying that variant. However, investigating the specific effects of heteroplasmic mtDNA variants on human neuronal function has been challenging. Studies using patient-derived cells cannot conclusively attribute observed phenotypes to a single mtDNA variant, while conventional genome editing approaches are not applicable to mtDNA. Here, we use DddA-derived cytosine base editor (DdCBE) to introduce pathogenic heteroplasmic mtDNA variants into Neurogenin 2 (NGN2)-inducible human induced pluripotent stem cells (iPSCs). We focus on two variants in the genes MT-ND1 and MT-ND5 belonging to complex I (CI), the largest component of the mitochondrial respiratory chain and a frequent contributor to human disease, including the incurable neurodevelopmental disorder Leigh syndrome. mtDNA-edited iPSC lines exhibit low off-target editing and maintain similar heteroplasmy following subclonal isolation and differentiation into NGN2-induced neurons (iNs). Although the CI variants do not substantially affect mitochondrial energy metabolism in undifferentiated iPSCs, they reduce mitochondrial membrane potential in iNs where they drive a transcriptional reprogramming indicative of impaired neuronal commitment. These findings suggest that heteroplasmic CI variants are sufficient to disrupt neural fate specification even at relatively low heteroplasmy. More broadly, mtDNA editing in human iPSCs provides a powerful platform to investigate how mitochondrial fitness and heteroplasmy influence development and disease.
ER -