Figure 6.

Ultrastructural imaging of OE shows damaged mitochondria in dendritic knobs of hAPP-expressing OSNs. A, Schematic of OE depicting the superficial sustentacular support cells lining the apical surface with OSN dendritic knobs protruding between them into the lumen. Electron micrographs corresponding to the OE apical region (red boxed region in schematic) with tetO-hAPP control (middle) showing three support cells, two with distinct nuclei (shaded green), and portions of four OSN dendritic knobs (shaded blue) protruding into the lumen among the fragmented cilia, while an OMP-hAPP mutant (bottom) shows disrupted support cell organization (green nucleus) and very few OSN dendritic knobs (one shaded blue). B, Comparison of an OSN dendritic knob from tetO-hAPP control (top panels) and OMP-hAPP mutant (bottom panels) reveals a clear alteration in the mitochondrial morphology of OMP-hAPP animals, which appear dark with indistinct features compared with the healthy appearance of mitochondria in the control animals showing clear cisternae. The panels on the right correspond to the boxed regions on the left panels. Arrowheads point to mitochondria. Scale bars: A, 2 µm; B, 500 nm.