C19orf12 Deficiency Triggers Coordinated Alterations in Lipid Homeostasis, Autophagy, and Ferroptosis

Background The C19orf12 gene encodes a poorly characterized protein, and mutations in this gene cause the rare neurodegenerative disorder Mitochondrial Membrane Protein–Associated Neurodegeneration (MPAN). Previous studies have described diverse cellular phenotypes associated with C19orf12 deficiency, but each typically focused on a single aspect. Here, we systematically tracked multiple cellular phenotypes to elucidate how C19orf12 dysfunction disrupts cellular homeostasis. Methods A multimodal approach was employed to characterize the consequences of C19orf12 loss. Proteomics identified altered pathways, digital western blotting assessed autophagy and ferroptosis proteins, and lipidomics profiled global lipid changes. Confocal imaging tracked fatty acid trafficking, and Seahorse extracellular flux analysis evaluated β-oxidation and mitochondrial respiration. Results MPAN fibroblasts exhibit concurrent defects in autophagy, ferroptosis, and lipid metabolism. Autophagy is impaired at multiple stages (initiation, elongation, and termination) and cells are more susceptible to ferroptosis, with lipid alterations functionally linking the two processes. Lipid dysfunction is marked by elevated triacylglycerol levels and altered phospholipid composition, confirmed also in adipocyte cells. Fatty acid intracellular targeting to lipid droplets and mitochondria remains preserved, while fatty acid uptake and mobilization from lipid droplets are reduced and delayed. This leads to progressive lipid accumulation, which is inefficiently oxidized by mitochondria, further compromising energy metabolism. Conclusion Loss of C19orf12 uncouples fatty acid utilization from lipid droplet turnover, causing triacylglycerol accumulation and multi-stage autophagy impairment. These findings reveal a functional link between fatty acid metabolism and lipid droplet dynamics with ferroptosis and autophagy, highlighting lipid accumulation as a potential target for therapeutic intervention in MPAN, in addition to autophagy modulation.