Saturday, January 8, 2022

The dynamin-related protein 1 is decreased and the mitochondrial network is altered in Friedreich’s ataxia cardiomyopathy

Bojjibabu Chidipi, Mariana Burgos Angulo, Syed Islamuddin Shah, Michelle Rieser, Ganim Ullah, Thomas V. McDonald, Sami F. Noujaim; The International Journal of Biochemistry & Cell Biology, Volume 143, 2022, 106137, doi:10.1016/j.biocel.2021.106137. 

 We found a significantly higher mitochondrial footprint, decreased mitochondrial fission protein dynamin-related protein, and mitochondrial fission rate over fusion with more giant mitochondrial clusters in human induced pluripotent stem cell derived cardiomyocytes from a patient with Friedreich ataxia hypertrophic cardiomyopathy, compared to an unaffected individual. We also found significantly depolarized mitochondrial membrane potential and higher reactive oxygen species levels in Friedreich ataxia human induced pluripotent stem cell cardiomyocytes. Our results show that frataxin's depletion may dampen the mitochondrial fission machinery by reducing dynamin-related protein1. The loss of mitochondrial fission might lead to elevated reactive oxygen species and depolarized mitochondrial membrane potential, which may cause oxidative damage in Friedreich ataxia hypertrophic cardiomyopathy. Further investigations are needed to identify the mechanism of downregulating dynamin-related protein1 due to the frataxin deficiency in Friedreich ataxia hypertrophic cardiomyopathy.