APP and Alzheimer disease: The relative expression level of the Mfn gene in AD model flies (elav-Gal4C155/+;+/+;UAS-Aβ42E693G/+ and elav-Gal4C155/+;+/+;UAS-APP.C99-UAS-MAPT/+) was significantly decreased to 1.7- and 0.7-fold, respectively (Fig. 6H), while overexpression of Miro in AD model flies (elav-Gal4C155/+;UAS-Miro/+;UAS-Aβ42E693G/+ and elav-Gal4C155/+;UAS-Miro/+;UAS-APP.C99-UAS-MAPT/+) showed significantly increased mitochondrial average length to 5.2- and 4.8-fold, respectively (Fig. 6H).