iron-sulfur assembly mitochondria briefs

Frataxin-deficient autonomic neurons fire five-fold more spikes, raise mitochondrial ROS, and de-repress MEG3

Lees, Zhang, Dottori, Napierala and colleagues show that hyperexcitability is a cell-autonomous property of human Friedreich ataxia autonomic neurons, not only a downstream consequence of dying heart or gut tissue. Frataxin is the mitochondrial iron-delivery protein for iron-sulfur cluster assembly. The cultures keep low FXN mRNA and protein, raise mitochondrial reactive oxygen species, shift from networked to tubular mitochondria, and die more. The authors do not report cluster nuclearity, so the bioinorganic frame is frataxin loss and mitochondrial oxidant load, not a measured [2Fe-2S] or [4Fe-4S] occupancy.