G-quadruplex-mediated reduction of a pathogenic mitochondrial heteroplasmy

Authors

Mansur M. Naeem, Institute of Medical Science.
Rathena Maheshan, Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada.
Sheila R. Costford, Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada.
Azizia Wahedi, Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada.
Marko Trajkovski, National Institute of Chemistry, Slovenian NMR Center, Ljubljana, Slovenia.
Janez Plavec, National Institute of Chemistry, Slovenian NMR Center, Ljubljana, Slovenia.
Liliya A. Yatsunyk, Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore PA, USA.
Grzegorz L. Ciesielski, Department of Chemistry, Auburn University at Montgomery, Montgomery, AL, USA.
Brett A. Kaufman, Center for Metabolism and Mitochondrial Medicine, Division of Cardiology, Vascular Medicine Institute, Department of Medicine, University of Pittsburgh Medical School, Pittsburgh, PA, USA.
Neal Sondheimer, Institute of Medical Science.

Document Type

Article

Publication Date

10-1-2019

Subject Area

Berberine (chemistry); Berberine Alkaloids (chemistry, pharmacology); Cells, Cultured; DNA Polymerase gamma (metabolism); DNA, Mitochondrial (chemistry, drug effects, genetics); Fibroblasts (cytology, drug effects); G-Quadruplexes (drug effects); Genetic Variation; Humans; Leigh Disease (genetics, metabolism)

Abstract

Disease-associated variants in mitochondrial DNA (mtDNA) are frequently heteroplasmic, a state of co-existence with the wild-type genome. Because heteroplasmy correlates with the severity and penetrance of disease, improvement in the ratio between these genomes in favor of the wild-type, known as heteroplasmy shifting, is potentially therapeutic. We evaluated known pathogenic mtDNA variants and identified those with the potential for allele-specific differences in the formation of non-Watson-Crick G-quadruplex (GQ) structures. We found that the Leigh syndrome (LS)-associated m.10191C variant promotes GQ formation within local sequence in vitro. Interaction of this sequence with a small molecule GQ-binding agent, berberine hydrochloride, further increased GQ stability. The GQ formed at m.10191C differentially impeded the processivity of the mitochondrial DNA polymerase gamma (Pol γ) in vitro, providing a potential means to favor replication of the wild-type allele. We tested the potential for shifting heteroplasmy through the cyclical application of two different mitochondria-targeted GQ binding compounds in primary fibroblasts from patients with m.10191T>C heteroplasmy. Treatment induced alternating mtDNA depletion and repopulation and was effective in shifting heteroplasmy towards the non-pathogenic allele. Similar treatment of pathogenic heteroplasmies that do not affect GQ formation did not induce heteroplasmy shift. Following treatment, heteroplasmic m.10191T>C cells had persistent improvements and heteroplasmy and a corresponding increase in maximal mitochondrial oxygen consumption. This study demonstrates the potential for using small-molecule GQ-binding agents to induce genetic and functional improvements in m.10191T>C heteroplasmy.

Publication Title

Human molecular genetics

Volume

28

Issue

19

First Page

3163

Last Page

3174

Digital Object Identifier (DOI)

10.1093/hmg/ddz153

PubMed ID

31261379

E-ISSN

1460-2083

Language

eng

Citation Information

Naeem, Mansur M.; Maheshan, Rathena; Costford, Sheila R.; Wahedi, Azizia; Trajkovski, Marko; Plavec, Janez; Yatsunyk, Liliya A.; Ciesielski, Grzegorz L.; Kaufman, Brett A.; and Sondheimer, Neal, "G-quadruplex-mediated reduction of a pathogenic mitochondrial heteroplasmy" (2019). UNF Faculty Research and Scholarship. 3284.
https://digitalcommons.unf.edu/unf_faculty_publications/3284