Fig. 2

Morphological manifestations of mouse ABSCs during culture. A Brightfield images showing the cell morphology of P0, P1, and P2 airway epithelial cells derived from diced tracheal tissue or cell suspensions produced by dispase and trypsin digestion co-cultured with pre-seeded MMC-treated NIH/3T3 cells in MPAEC culture medium containing Y-27632. White dotted lines indicate the well-defined stem cell-like clones, while blue dotted lines indicate that cells in the clones were undergoing differentiation. B Well-defined stem cell-like clones were observed in P0 during culture with 3T3-CM, MEF-CM, or RbEF-CM containing Y-27632. In the P1, when cultured with 3T3-CM, cells in the clones kept a typical cobblestone shape and expanded with minimal cell–cell contact, while in MEF-CM and RbEF-CM culture, some cells in the clones began to differentiate. White dotted lines indicate the well-defined stem cell-like clones, while blue dotted lines indicate that cells in the clones were undergoing differentiation. C In the P5, well-defined stem cell-like clones were maintained only in the 3T3-CM containing Y-27632 culture system, whereas when cultured with MEF-CM or RbEF-CM, cells within the clones began to undergo differentiation