Mitochondrial dysfunctions in leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL)

PLoS One. 2019 Oct 31;14(10):e0224173. doi: 10.1371/journal.pone.0224173. eCollection 2019.

Abstract

Several inherited human diseases have been linked to mitochondrial aminoacyl-tRNA synthetases (mtARSs). Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) is a leukodystrophy caused by mutations in the DARS2 gene which encodes mitochondrial aspartyl-tRNA synthetase. As mitochondrial ARSs are key components of the mitochondrial translation apparatus, we investigated the effects of DARS2 mutations on mitochondrial functions and mitochondrial morphology in an LBSL patient. In fibroblasts from the patient with LBSL, biosynthesis of respiratory chain complex proteins encoded by mitochondrial DNA was decreased, while those encoded by nuclear DNA were not. Cellular oxygen consumption rates and respiratory control ratio were decreased in the LBSL patient; in addition, fragmentation of mitochondria was increased, while their tubular elongation and interconnectivity were decreased. Taken together, these findings suggest that DARS2 mutations impair translations of mitochondrial DNA-encoded respiratory chain complex proteins, consequently causing dysfunction of cellular respiration and impediment of mitochondrial dynamics, which highlights the role of mtARSs in the maintenance of normal mitochondrial bioenergetics and dynamics.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aspartate-tRNA Ligase / deficiency*
  • Aspartate-tRNA Ligase / genetics
  • Base Sequence
  • Fibroblasts / pathology
  • Humans
  • Leukoencephalopathies / genetics
  • Leukoencephalopathies / pathology*
  • Mitochondria / pathology*
  • Mitochondrial Diseases / genetics
  • Mitochondrial Diseases / pathology*
  • Mutation

Substances

  • Aspartate-tRNA Ligase
  • DARS2 protein, human

Supplementary concepts

  • Leukoencephalopathy with Brainstem and Spinal Cord Involvement and Lactate Elevation

Grant support

This research was funded by Chang Gung Memorial Hospital, grant number CMRPG8E0291, CMRPG8E0292, CMRPG8E0293, CORPG8F1021, CORPG8F1022, CMRPG8H0191 and Ministry of Science and Technology, Taiwan, grant number MOST 106-2314-B-182A-057-MY3, 105-2314-B-182A-010. The aforementioned funding sources had no involvement in study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the article for publication.