TEMs for the qualitative assessment of mitophagy in LHON cells
Qualitative TEM mitophagy activity assessment on LHON 3460 fibroblasts (mito=mitochondria; AV=autophagy vacuoles; Arrow= autophagy vacuole membrane) (A). TEMs for the qualitative assessment of RGCs in human post-mortem retinas are represented in the following panels: (B) On the left, an axon hillock (bordered with red lines, left panel) of an RGC from an LHON 3460-affected patient can be observed with numerous mitochondria (M) at the entrance of its axon with its characteristic cytoskeletal elements. Mitochondria have been distinguished accordingly to the presence of mitochondrial cristae. On the right, an RGC from an LHON 11778 affected patient with a mitochondrion (inset, right panel) is surrounded by an isolation membrane (IM) in the process of forming an autophagosome vesicle documenting an early stage of mitophagy (right panel). (C) Post-mortem TEM images of RGCs of LHON-carrier 11778 characterized by prominent cytoplasmic vacuolization due to a high-level of compensatory mitobiogenesis. In the lower left panel, a red line marks the limits of the two RGCs present in the TEM image shown. On the right, higher magnification with relative inset of an RGC from an LHON 11778-carrier patient where it is possible to well distinguish the increased mitochondrial biogenesis of an LHON-carrier individual. Mitochondria (M) have been distinguished accordingly to the presence of mitochondrial cristae.