To analyze differentiation potential of porcine progenitor epithelial cells, cells were seeded in culture dishes pre-coated with collagen I. The cells were cultured in epithelial cell differentiation medium containing 50% epithelial growth media supplemented with bovine pituitary extract (70 mg/ml), human epidermal growth factor (5 ng/ml), insulin (5 mg/ml), and hydrocortisone (0.5 mg/ ml) (MEGM, Lonza, Walkersville, MD) and 50% MSC-CM medium. After 5 days of incubation at 37uC, cells were observed for morphology and cells grown on coverslips were examined for the expression of Aqua5 (marker for type I pneumocytes) and SPC (marker for type II pneumocytes) by using goat anti-human Aqua5 (Santa Cruz Biotechnology) and rabbit anti-human SPC (Millipore) primary antibodies by IFA as described above.