Trans-Mitochondrial Cybrid Generation from mtDNA Patient Platelets: An Efficient Protocol Optimizing Colony Selection...

Area of Science:

• Mitochondrial biology
• Genetics
• Cell biology

Background:

• Trans-mitochondrial cybrid cell line generation is the gold standard for assessing mitochondrial DNA (mtDNA) variant pathogenicity.
• Traditional cybrid generation methods are inefficient and time-consuming.
• There is a need for improved protocols to study mtDNA variants, especially those affecting the electron transport chain.

Purpose of the Study:

• To describe a highly efficient protocol for generating trans-mitochondrial cybrid cell lines.
• To demonstrate the utility of this protocol for studying mtDNA variants of unknown significance.
• To assess the pathogenicity of a specific MT-ND1 variant using the generated cybrid lines.

Main Methods:

• Fusion of human platelets with mtDNA-depleted osteosarcoma 143B (Rho0) cells.
• Utilizing colony selection techniques to improve yield and reduce generation time.
• Generating cybrid cell lines with varying heteroplasmy levels for an MT-ND1 variant (m.3985G>A).
• Assessing mitochondrial respiration via high-resolution respirometry.

Main Results:

• The described protocol significantly enhances the efficiency and yield of cybrid cell line generation.
• Colony selection techniques expedite the isolation of high-level heteroplasmy mtDNA mutant cybrid lines.
• Cybrid mutants with high-level heteroplasmy for MT-ND1 m.3985G>A exhibited impaired Complex I-dependent respiration.
• This functional impairment suggests the m.3985G>A variant is likely pathogenic.

Conclusions:

• The developed protocol offers a more efficient and effective method for generating trans-mitochondrial cybrid cell lines.
• This improved methodology facilitates the study of mtDNA variant pathogenicity, particularly for variants affecting mitochondrial respiration.
• The study provides evidence that the MT-ND1 m.3985G>A variant is likely pathogenic, impacting mitochondrial function.