Unravelling the molecular basis of novel leukodystrophies

Project Summary

Approximately half of patients with leukodystrophies, or genetic disorders of central nervous system myelin, do not have an identified genetic defect. HGS of patients with infantile onset diffuse leukoencephalopathy and brainstem signal abnormalities revealed  mutation of DARS as the molecular culprit of this disease. 

DARS encodes a cytoplasmic aspartyl-tRNA synthetase commonly thought to charge its cognate tRNA with aspartate during protein biosynthesis, though pathogenesis in this and other aminoacyl tRNA synthetase (ARS) disorders may be related to as yet unknown functions in catabolism. We propose to explore the DARS related leukoencephalopathy phenotype, while clarifying its mechanisms and avenues for potential therapeutics. 

DARS mutated patient iPSC cells of different lineages (neuronal, glial and oligodendrocytes) will be screened for viability, morphology, activation induced calcium handling, and profiled by RNA-seq to examine the genome-wide effects of DARS mutations. This project will further involve the development of robust assays to quantify myelination of target cells and various strategies to improve oligodendrocyte function in DARS patients. Controls will be non-mutated cells, isogenic parental lines and CRISPR-based genome corrected DARS iPSC and iPSC with engineered DARS mutations. We anticipate that this work will provide a robust framework for understanding the etiology of DARS-associated Hereditary  Spastic Paraplegia and the role of DARS in myelination and brain function.