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Matching Mitochondrial DNA Haplotypes for Circumventing Tissue-Specific Segregation Bias
Jianxin Pan1, Li Wang2, Charles Lu3
1Reproductive Medicine Center, Zhongshan Hospital, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, China.
Iscience
|March 22, 2019
Summary
Matching mitochondrial DNA (mtDNA) haplotypes may prevent segregation issues in mitochondria replacement therapy. This study found that donor-recipient mtDNA matching could circumvent segregation, reducing unknown risks associated with therapy.
Area of Science:
- Genetics and Genomics
- Mitochondrial Biology
- Reproductive Medicine
Background:
- Mitochondria replacement therapy (MRT) aims to prevent transmission of mitochondrial diseases.
- Donor-recipient mitochondrial DNA (mtDNA) mismatch can lead to segregation, posing unknown risks.
- The impact of mtDNA haplotype matching on segregation in MRT is not well understood.
Purpose of the Study:
- To investigate whether matching mtDNA haplotypes ameliorates segregation in heteroplasmic individuals.
- To determine the relationship between donor mtDNA heteroplasmy levels and segregation severity.
- To assess the inheritance pattern of mtDNA segregation from embryonic development to adult tissues.
Main Methods:
- Generation of heteroplasmic mice with varying degrees of donor mtDNA heteroplasmy using three single nucleotide polymorphisms.
- Monitoring of mtDNA segregation severity in tissues and preimplantation embryos.
- Statistical analysis to evaluate selective replication of donor mtDNA and track its distribution over lifespan.
Main Results:
- Mitochondrial DNA segregation was observed in tissues with low-level donor mtDNA heteroplasmy, diminishing as heteroplasmy levels increased.
- Donor mtDNA distribution in embryonic blastomeres mirrored patterns observed in adult tissues.
- No selective replication of donor mtDNA was detected during the lifespan of heteroplasmic mice; uneven embryonic distribution led to tissue segregation.
Conclusions:
- The 'segregation' observed in tissues originates from uneven donor mtDNA distribution in early embryonic development.
- Increasing donor mtDNA heteroplasmy levels naturally lead to more even distribution, thereby reducing segregation.
- Donor-recipient mtDNA matching is suggested as a strategy to circumvent segregation issues in mitochondria replacement therapy.
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