Fig. 2.

Characterization of unique 3D structures. (A) Representative bright-field image, schematic, and description for each class (prestructure, spheroid, and tubule) of organoid structures. Scale bars: 100 μm. (B) Bright-field images and corresponding immunofluorescence staining for E-cadherin (purple) in non-differentiated (E-cadherin negative; prestructures) and differentiated (E-cadherin positive; spheroids and tubules) structures. Scale bars: 50 μm. (C) Representative bright-field images of tubule development in the culture model. Tubules are often part of more complex 3D structures, including the globular, supportive prestructures. Scale bars: 25 μm. (D) Differentiated tubule structures demonstrate basolateral localization of Na⁺/K⁺-ATPase (green). Nuclei are stained with DAPI (blue). Scale bar: 50 μm. (E) Spheroids and tubules additionally demonstrate primary cilia, as indicated by acetyl-α-tubulin (red) puncta on the apical membrane. Basolateral Na⁺/K⁺-ATPase (green) and nuclear DAPI staining (blue) are also shown. Arrows indicate cilia, positively stained by acetyl-α-tubulin. Scale bars: 25 μm.