Figure 3: 3D complexity of the lateral and basal cytoplasmic membranes of human corneal endothelial cells (CECs).

(A) Labeling of calnexin in the endoplasmic reticulum (central cornea from a 48 years old patient with stromal lattice dystrophy) or labeling of the intermediate filament vimentin (central cornea from a 16 years old patient with keratoconus), highlight the lateral expansions of the cytoplasm, which create cell interdigitation. ZO-1 and myosin IIa were used to identify the apical surface. (B) The transmembraneous N-cadherin highlighted the opposing surfaces of CECs, showing maximal expansions of cytoplasmic membrane in contact with Descemet’s membrane, in contrast to the regular hexagonal shape of the apical surface. Cell contours were manually drawn (in yellow) to measure the cell perimeter (central cornea from a 16 years old patient with keratoconus). (C) Double-labeling of COX IV (mitochondrial network) and CD166 (lateral membranes) revealed the complexity of lateral membranes that delimited intercellular segmented spaces beginning immediately beneath the apical surface (central cornea from a 65 years old patient with stromal lattice dystrophy). The labeling of NCAM, expressed exclusively in the lateral membranes, showed, at 3 different levels, the increasing tortuosity of the membrane expansions toward Descemet’s membrane (central cornea from a 36 years old patient with keratoconus. All patients of this panel had a normal corneal endothelium).