Figure 3. Cldn10-positive cells with cuboidal to oval shape line the alveolar epithelium in IPF lungs.

Resin-embedded lung sections from patients with IPF were labeled for Cldn10 using immunogold labeling method. Arrows in (B, C, F & H) denote Cldn10 signals. (A) Alveolar epithelium with mild fibrosis is lined by a monolayer of metaplastic epithelial cells with cuboidal to oval shape (Asterisks). (B) Cldn10 expression (arrows) are located in close proximity to the tight junction (TJ) between the two adjacent cells. Note that the the Cldn10 signals shown belong to the epithelial cell circled by arrowheads in (A). (C) Cldn10 expression (arrows) are located in the cytoplasm (Cyto) and nucleus (Nuc). Additional photomicrographs showing the spatial association of this cell with the subjacent fibroblast are presented in Supplemental Figure S3F, G & H. (D, E, F) Cldn10 expression (tiny black dots in areas circled by dashed lines in (E) and arrows in (F) are located near the lateral membrane (the boundary between the two adjacent epithelial cells is designated by arrowheads in (E & F). The Cldn10 signals are not located near to the tight junction (TJ in E). Note there is a deposition of collagen bundles in the subjacent interstitium of the Cldn10-positive epithelial cell (D). (G, H) Alveolar epithelium lined by a cuboidal cell with nuclear expression of Cldn10. (G) Dot-dashed and dashed line are respectively drawn slightly outside the nucleolus and cytoplasmic membrane of the cuboidal cell. Note that the cell displays large nucleus-to-cytoplasm (N/C) ratio and huge nucleolus. (H) Magnified view of the boxed region in (G) displays nuclear expression of Cldn10. Original magnifications: x2,000 (A); x100,000 (B, C); x15,000 (D); x60,000 (E); x120,000 (F); x12,000