Figure 1.

The conditional reprogramming culture (CRC) method enhances preservation of nasal airway basal progenitor cells. (A) Phase-contrast microscopy of nasal epithelial cells grown using the bronchial epithelial growth media (BEGM) and CRC techniques reveals “scattered” and “colony” growth patterns, respectively. Black arrows indicate individual cells (A) or the colony edge (B). Red arrows in A indicate feeder cells. Scale bars: 200 μm. Values represent the mean (±SEM). (B) Frequency of cytokeratin-5– and -14–expressing passage (P) 2 cells recovered from BEGM and CRCs. Representative of studies done in three donors. (C) The surface phenotype of P2 cells recovered from BEGM cultures or CRCs was determined by flow cytometry. Bivariate FACS plots of cells stained for the tetraspanin (CD151) and tissue factor or α6 integrin (CD49f). Representative of three to four donors. (D) Quantification of cell subtype frequency as determined by flow cytometry (n = 3–4 donors). Values represent the mean (±SEM). (E) The cell cycle distribution of P2 nasal cells recovered from CRC or BEGM cultures was determined by saponin/propidium iodide staining and flow cytometry. G1, gap 1; G2M, gap 2 mitosis; S, DNA synthesis (n = 3–4 donors). Values represent the mean (±SEM). (F) The effect of culture technique on clone-forming cell frequency (CFCF). Nasal brushings were cultured at P2 using the CRC or BEGM method. At P3, cells were cultured in the same medium or switched to the alternative medium. CFCF was determined by limiting dilution analysis. Values represent the mean (±SEM). Representative of studies done in three donors.