Defective palmitoylation of transferrin receptor triggers iron overload in Friedreich ataxia fibroblasts

Blood. 2021 Apr 15;137(15):2090-2102. doi: 10.1182/blood.2020006987.

Abstract

Friedreich ataxia (FRDA) is a frequent autosomal recessive disease caused by a GAA repeat expansion in the FXN gene encoding frataxin, a mitochondrial protein involved in iron-sulfur cluster (ISC) biogenesis. Resulting frataxin deficiency affects ISC-containing proteins and causes iron to accumulate in the brain and heart of FRDA patients. Here we report on abnormal cellular iron homeostasis in FRDA fibroblasts inducing a massive iron overload in cytosol and mitochondria. We observe membrane transferrin receptor 1 (TfR1) accumulation, increased TfR1 endocytosis, and delayed Tf recycling, ascribing this to impaired TfR1 palmitoylation. Frataxin deficiency is shown to reduce coenzyme A (CoA) availability for TfR1 palmitoylation. Finally, we demonstrate that artesunate, CoA, and dichloroacetate improve TfR1 palmitoylation and decrease iron overload, paving the road for evidence-based therapeutic strategies at the actionable level of TfR1 palmitoylation in FRDA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, CD / metabolism*
  • Cells, Cultured
  • Fibroblasts / metabolism
  • Fibroblasts / pathology*
  • Friedreich Ataxia / complications
  • Friedreich Ataxia / metabolism*
  • Friedreich Ataxia / pathology
  • Humans
  • Iron / metabolism
  • Iron Overload / etiology
  • Iron Overload / metabolism*
  • Iron Overload / pathology
  • Lipoylation
  • Mitochondria / metabolism
  • Mitochondria / pathology
  • Receptors, Transferrin / metabolism*

Substances

  • Antigens, CD
  • CD71 antigen
  • Receptors, Transferrin
  • Iron