Deoxyhypusine synthase mutations alter the post-translational modification of eukaryotic initiation factor 5A...

Area of Science:

• Genetics and Molecular Biology
• Neuroscience
• Rare Diseases

Background:

• Deoxyhypusine synthase (DHPS) deficiency is a rare genetic disorder.
• DHPS enzyme is crucial for activating eukaryotic initiation factor 5A (eIF5A) in mRNA translation.
• Mutations in DHPS are linked to neurodevelopmental issues like intellectual disability and seizures.

Purpose of the Study:

• To investigate the molecular mechanisms by which DHPS mutations impact neurodevelopment.
• To understand the functional consequences of DHPS variants on eIF5A modification and mRNA translation.

Main Methods:

• Generated patient-derived lymphoblast cell lines with DHPS variants.
• Created a mouse model with brain-specific Dhps deletion.
• Analyzed DHPS protein levels, enzyme activity, and eIF5A post-translational modifications (acetylation and hypusination).
• Assessed impact on mRNA translation and protein expression in neuronal development.

Main Results:

• Human DHPS variants reduce DHPS protein abundance and impair enzyme function.
• DHPS variants alter eIF5A modification, increasing nuclear eIF5A-acetylation and decreasing cytoplasmic eIF5A-hypusination.
• Loss of brain Dhps in mice impairs eIF5A-hypusination-dependent mRNA translation.
• Altered protein expression affecting neuronal development and function was observed in the mouse model.

Conclusions:

• DHPS deficiency disrupts neuronal function through impaired eIF5A-dependent mRNA translation.
• This study provides critical insights into the molecular basis of DHPS deficiency and its impact on neurodevelopment.
• Findings offer a foundation for developing therapeutic strategies for this rare genetic disease.