A Combined Drug Treatment That Reduces Mitochondrial Iron and Reactive Oxygen Levels Recovers Insulin Secretion in NAF-1-Deficient Pancreatic Cells
2Department of Surgery, School of Medicine, University of Missouri, USA
A homozygous mutation in the NAF-1 encoding gene CISD2 (of the NEET family of [2Fe-2S] proteins, causes the autosomal recessive disorder Wolfram Syndrome Type-2 (WFS-T2) that is manifested in a plethora of pathologies, particularly pancreatic β-cell dysfunction and ensuing death. Preliminary observations of iron accumulation and increased ROS formation in NAF-1-stably repressed INS-1E pancreatic cells (a model of WFS-T2) led us to explore the possible involvement of ferroptosis in the WFS-T2 phenotype. Firstly, we observed that NAF-1 repression led to impaired mitochondrial respiration, increased iron accumulation and increased ROS production that was reflected also in reduced glutathione levels and oxidative damage of the ER and mitochondria. The biochemical changes observed in WFS-T2 model cells were manifested functionally as reduced glucose-induced insulin secretion. To test ferroptosis potential role in the WFS-T2 phenotype, we used a combined iron-chelation + glutathione stimulator as joint tool to reverse the affected parameters, biochemical, structural and functional. We found that a combined treatment with the cell permeant iron chelator deferiprone and the glutathione precursor N-acetyl cysteine, promoted the structural repair of mitochondria and ER, decreased mitochondrial labile iron and ROS levels, and restored glucose-stimulated insulin secretion. Additionally, treatment with the ferroptosis inhibitor ferrostatin-1 decreased cellular ROS formation and improved cellular growth of NAF-1 repressed pancreatic cells. Our findings reveal that suppressed expression of NAF-1 is associated with the development of ferroptosis-like features in pancreatic cells, and that reducing the levels of mitochondrial iron and ROS levels could be used as a therapeutic avenue for WFS-T2 patients.