عنوان

Directional Shift in Mitochondrial Heteroplasmy

Number

TL54477

.Language of Text, Soundtrack etc

انگلیسی

Title Proper

Directional Shift in Mitochondrial Heteroplasmy

General Material Designation

[Thesis]

First Statement of Responsibility

Mohammad Naeem, Mansur

Subsequent Statement of Responsibility

Sondheimer, Neal

Name of Publisher, Distributor, etc.

University of Toronto (Canada)

Date of Publication, Distribution, etc.

2020

Text of Note

188 p.

Dissertation or thesis details and type of degree

Ph.D.

Body granting the degree

University of Toronto (Canada)

Text preceding or following the note

2020

Text of Note

Diseases due to mitochondrial DNA (mtDNA) mutations are lethal and few therapeutic options are available. Because these mutations often exist in a state of heteroplasmy, the coexistence of wild-type and mutated mtDNA, strategies that can alter this ratio in favor of wild-type mtDNA ("heteroplasmy shifting") may be therapeutically useful. We found that the Leigh syndrome (LS)-associated m.10191C variant promotes G-Quadruplex (GQ) formation within local sequence in vitro. The GQ formed at m.10191C differentially impeded the processivity of the mitochondrial DNA polymerase gamma (POLG) in vitro, providing a potential means to favor replication of the wild-type allele. Treatment of patient fibroblasts with GQBA induced alternating mtDNA depletion and repopulation and was effective in shifting heteroplasmy towards the non-pathogenic allele. Following treatment, heteroplasmic m.10191T>C cells had increased in maximal mitochondrial oxygen consumption. We developed a high-throughput assay to screen 23,000 GQBA for preferential binding to m.10191C allele with minimal off-target effects and two compounds were identified with favourable characteristics. We observed that mitochondria in patient cells harbouring pathogenic heteroplasmic mtDNA mutation are hyperfused compared to controls. Fragmenting mitochondria by knock down of fusion genes led to shift in mitochondrial heteroplasmy. This study demonstrates the potential for using small-molecule GQ-binding agents to induce genetic and functional shift in m.10191T>C mutation and mitochondrial fragmentation may have synergistic effects.

Subject Term

Genetics

Subject Term

Molecular biology

Subject Term

Neurosciences

Mohammad Naeem, Mansur

Sondheimer, Neal

University of Toronto (Canada)

Electronic name

p

[Thesis]

276903

a

Y