Characterization of the mitofusin 2 R94W mutation in a knock-in mouse model

Area of Science:

• Genetics and Molecular Biology
• Neuroscience
• Mitochondrial Biology

Background:

• Charcot-Marie-Tooth disease (CMT) is a group of peripheral axonopathies affecting 1 in 2,500 individuals.
• Mutations in mitofusin 2 (MFN2) are the most common cause of severe inherited peripheral axonal degeneration, accounting for ~90% of cases.
• Understanding MFN2's role in neurodegeneration and developing preclinical models are crucial for CMT research.

Purpose of the Study:

• To generate and characterize a Mfn2 knock-in mouse model expressing the R94W mutation found in CMT patients.
• To investigate the functional consequences of the Mfn2(R94W) mutation in a mammalian model.
• To provide a valuable resource for studying molecular pathways in MFN2-related neurodegenerative diseases.

Main Methods:

• Generation of Mfn2(R94W) knock-in mice.
• Behavioral testing (open-field test).
• Morphological and biochemical analyses (mitochondrial fragmentation, ATP levels).

Main Results:

• Homozygous Mfn2(R94W) mice exhibit premature death and significant mitochondrial dysfunction (fragmentation, reduced ATP).
• Heterozygous Mfn2(R94W) mice display histopathological changes and age-dependent behavioral abnormalities indicative of mild peripheral neuropathy.
• While behavioral deficits do not fully replicate human CMT severity, the model offers insights into MFN2 point mutation effects.

Conclusions:

• The Mfn2(R94W) mouse model effectively recapitulates key aspects of MFN2-related mitochondrial dysfunction and peripheral neuropathy.
• This model serves as a valuable tool for preclinical studies and investigating the molecular mechanisms underlying MFN2-associated CMT.
• Further research using this model can advance the development of therapeutic strategies for inherited axonal degenerations.