Hypoxia Rescues Frataxin Loss by Restoring Iron Sulfur Cluster Biogenesis.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31031004.
- Also identified by DOI 10.1016/j.cell.2019.03.045 and PMC identifier 6911770.
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Abstract
Friedreich's ataxia (FRDA) is a devastating, multisystemic disorder caused by recessive mutations in the mitochondrial protein frataxin (FXN). FXN participates in the biosynthesis of Fe-S clusters and is considered to be essential for viability. Here we report that when grown in 1% ambient O<sub>2</sub>, FXN null yeast, human cells, and nematodes are fully viable. In human cells, hypoxia restores steady-state levels of Fe-S clusters and normalizes ATF4, NRF2, and IRP2 signaling events associated with FRDA. Cellular studies and in vitro reconstitution indicate that hypoxia acts through HIF-independent mechanisms that increase bioavailable iron as well as directly activate Fe-S synthesis. In a mouse model of FRDA, breathing 11% O<sub>2</sub> attenuates the progression of ataxia, whereas breathing 55% O<sub>2</sub> hastens it. Our work identifies oxygen as a key environmental variable in the pathogenesis associated with FXN depletion, with important mechanistic and therapeutic implications.
Medical subject headings
- Hypoxia
- Iron-Binding Proteins
- Iron-Sulfur Proteins