Deoxyhypusine synthase mutations alter the post-translational modification of eukaryotic initiation factor 5A resulting in impaired human and mouse neural homeostasis

Leah R. Padgett, Mollie R. Shinkle, Spencer Rosario, Tracy Murray Stewart, Jackson R. Foley, Robert A. Casero, Myung Hee Park, Wendy K. Chung, Teresa L. Mastracci

Research output: Contribution to journalArticlepeer-review

Abstract

DHPS deficiency is a rare genetic disease caused by biallelic hypomorphic variants in the Deoxyhypusine synthase (DHPS) gene. The DHPS enzyme functions in mRNA translation by catalyzing the post-translational modification, and therefore activation, of eukaryotic initiation factor 5A (eIF5A). The observed clinical outcomes associated with human mutations in DHPS include developmental delay, intellectual disability, and seizures. Therefore, to increase our understanding of this rare disease, it is critical to determine the mechanisms by which mutations in DHPS alter neurodevelopment. In this study, we have generated patient-derived lymphoblast cell lines and demonstrated that human DHPS variants alter DHPS protein abundance and impair enzyme function. Moreover, we observe a shift in the abundance of the post-translationally modified forms of eIF5A; specifically, an increase in the nuclear localized acetylated form (eIF5AAcK47) and concomitant decrease in the cytoplasmic localized hypusinated form (eIF5AHYP). Generation and characterization of a mouse model with a genetic deletion of Dhps in the brain at birth shows that loss of hypusine biosynthesis impacts neuronal function due to impaired eIF5AHYP-dependent mRNA translation; this translation defect results in altered expression of proteins required for proper neuronal development and function. This study reveals new insight into the biological consequences and molecular impact of human DHPS deficiency and provides valuable information toward the goal of developing treatment strategies for this rare disease.

Original languageEnglish (US)
Article number100206
JournalHuman Genetics and Genomics Advances
Volume4
Issue number3
DOIs
StatePublished - Jul 13 2023

Keywords

  • DHPS
  • DHPS deficiency
  • eIF5A
  • hypusination
  • hypusine
  • mRNA translation
  • neurodevelopment
  • rare disease

ASJC Scopus subject areas

  • Genetics(clinical)
  • Molecular Medicine

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