Patient‐Derived Neurons Exhibit α‐Synuclein Pathology and Previously Unrecognized Major Histocompatibility Complex Class I Elevation in Mitochondrial Membrane Protein–Associated Neurodegeneration

Mitochondrial membrane protein-associated neurodegeneration (MPAN) from the neurodegeneration with brain iron accumulation (NBIA) family is a rare neurodegenerative disease marked by α-synuclein aggregation, brain iron accumulation, and midbrain dopaminergic neuron degeneration. The mechanisms driving neuron vulnerability remain unclear. Our study aimed to develop a patient-derived disease model replicating key pathologies of patient brains. We generated induced pluripotent stem cell-derived midbrain dopaminergic neurons from MPAN patients and examined ultrastructural and biochemical markers of pathology. MPAN patient neurons displayed α-synuclein aggregation, axonal swellings, iron accumulation, and severe membrane destruction. In addition, levels of the major histocompatibility complex class I (MHC-I), linked to cellular stress and neurodegenerative processes, were elevated in patient neurons. Treatment with acetyl-leucine, a potentially neuroprotective compound, decreased MHC-I. This first patient-derived neuronal model of MPAN provides a useful tool for further research aimed at unraveling the complexities of this disease and developing potential therapeutic interventions.