Neurodegeneration in brain with iron accumulation (NBIA) defines a group of rare hereditary diseases with prominent features of iron deposition and related neuronal loss in the nervous system. Although significant progress in the genetic studies uncovered the essential role of mitochondrial dysfunction in the pathogenesis of NBIA, the underlying mechanism of mitochondrial abnormality and metal dysregulation in NBIA remains elusive. In this regard, we focused on the mitochondrial membrane proteins associated iron accumulation (MPAN) that was caused by genetic mutations in C19orf12, a protein with unknown function. In the pilot study, we analyzed human biopsy of an MPAN case, mouse brain tissue and human neuroblastoma M17 cell lines with C19orf12 knock-out (KO) to explore the role of C19orf12 in the mitochondria of MPAN and also in the normal mitochondria. Indeed, our preliminary data of imaging investigation on brain biopsy of MPAN conditions suggested mitochondria are impaired in the surviving neurons, which underscored the mitochondrial dysfunction in MPAN. The exploration of C19orf12 in vivo showed the mitochondrial localization and protein expression of C19orf12 in mouse brain tissues. Importantly, we found that C19orf12 is associated with mitochondrial complex IV of the electron transfer chain in vivo. In vitro study of C19orf12, mitochondrial respiration analysis of C19orf12 KO M17 cells showed impaired mitochondrial oxygen consumption in vitro. Furthermore, trace metal analysis showed both iron and copper dysregulation in the mitochondria of C19orf12 KO cells. Taken together, this exciting data demonstrated that the critical role of C19orf12 in mitochondrial function and metal regulation in the physiological condition and the likely related disturbance of C19orf12 during the pathogenesis of MPAN. Therefore, the further study to explore the mechanism of metal regulation in MPAN and how C19orf12 mutants impair mitochondrial function is warranted. The current application will shed light on the novel mechanism of C19orf12 that is linking mitochondrial dysfunction and metal dysregulation in the MPAN pathology.
Mitochondrial dysfunction plays a central role in the pathogenesis of neurodegeneration in brain with iron accumulation (NBIA), although the detailed mechanism is still elusive. In the application, we focus on Ch19orf12 which is the genetic cause of subset of NBIA and propose novel mechanism linking mitochondrial impairment and metal dysregulation in the pathogenesis of NBIA.
