Multidifferentiation potential of suspension-derived cells. (A) In addition to bone nodule formation detected by UV-fluorescence excitation of tetracycline-labeled cultures (week 1 SCF plus IL-3 suspension-derived cells cultured in CFU-O conditions shown here), (B) cells containing fat globules formed under adipogenic culture conditions (× 64). (C) RT-PCR confirmed that adipogenic cultures expressed PPAR-γ. (D) Typical cells that grew in a CFU-F assay that were initiated with cells removed from SSCs of the SCF plus IL-3 treatment group after 1 week (× 32.1). CFU-F cultures were stained with α-naphthyl acetate esterase followed by a counterstain with hematoxylin solution at 2 weeks. (E) The typical cells from CFU-F assays that were initiated with suspension-derived cells cultured in the presence of SCF plus IL-3 plus 20 ng/mL PDGF-BB (×32.1). (F) At 7, 14, and 21 days of suspension culture, test populations were removed from each suspension culture and plated in CFU-M assays; at termination (day 21), the cultures were stained with Giemsa to visualize the colonies generated. (G) Extent of desmin staining within individual cells comprising the fibroblastic colonies observed in panel F (× 20). (H) Graphic display of the fold expansion in CFU-Ms. A statistically significant difference (P < .05) in CFU-M expansion achieved in the different cytokine treatment groups on day 21 was observed. Each bar represents the mean ± SD (n = 3). (I) RT-PCR confirmed that CFU-M cultures expressed MyoD1 after 21 days. GAPDH indicates glyceraldehyde phosphate dehydrogenase.