OPA1 and Alzheimer disease: Similarly, the present study detected the diminished mitochondrial biogenesis related protein levels (PGC-1α, NRF-1, and TFAM), the reduced mitochondrial content (CS activity and mtDNA copy number), as well as increased mitochondrial fission protein levels (Drp1) and reduced mitochondrial fusion protein levels (Mfn1 and OPA1) in the hippocampus of APP/PS1 mice, showing attenuated mitochondrial biogenesis and imbalanced mitochondrial dynamics (increased mitochondrial fission over mitochondrial fusion) in this kind of AD animal model.