Author response image 1.

(A) Alveolosphere assay. Aged L-MSCs were co-cultured with aged AEC2s in the presence of FGF-10 (100 ng/ml). The alveolospheres were imaged by brightfield microscopy after 12 days of co-culture, and comparative outcomes are shown here (scale bar = 500 μm) (B) Alveolospheres in each well were counted. Alveolosphere size (volumes) were determined for each of the 2 co-culture groups. Nested scatterplot showing Mean ± SEM of all the alveolospheres counted in each well for each group (n = 2 mice; **p < 0.01; unpaired T-test). Data were natural log transformed before T-test.