Mitochondrial Dynamics and Bioenergetics in iPSC-Derived Neurons with Familial Alzheimer’s Disease Mutations

Summary Mitochondrial (MT) dysfunction is a hallmark of Alzheimer’s Disease (AD), but the specific defects across forms of AD are unknown. We measured multiple parameters of MT dynamics and function, and neurite degeneration, in iPSC-derived human neurons possessing natural and engineered mutations in PS1, PS2, and APP genes. Mutations in all three genes altered MT function measured by basal, ATP-linked, and maximal oxygen consumption rate; and spare respiratory capacity, with PS1/PS2 alleles being more severe than APP mutations. Electron flow through Complexes I-IV was decreased in PS1/PS2 mutations but; in contrast, APP alleles had only modest impairments of CI and CII. We measured aspects of MT dynamics including fragmentation, and neurite degeneration, both of which were dramatic in PS1/PS2 alleles, but essentially absent in APP alleles. The marked differences in MT pathology may occur from the distinct ways APP is processed into Aβ and may correlate with the disease severity.