Figure 1.
Correlation between BubR1 expression, the potential to differentiate, and senescence in adipose-derived mesenchymal stem cells. (A) hASCs were isolated from liposuction aspirates, cultured (passage 1), and propagated for 2-11 passages. Expression of p16INK4A as a senescence marker was determined using quantitative real-time PCR. Triplicate samples were normalized to GAPDH. (B) Protein extracts (100 µg) from each passage of ASCs were processed and immunoblotted with anti-BubR1, anti-SA-β-gal, and anti-actin antibodies. (C) Early (passage 1), middle (passage 5), and late (passage 9) ASCs were cultured in a control medium and an adipogenic medium. Passage 5 ASCs that showed the highest level of BubR1 in (B) formed the lipid droplets typical of the adipogenic phenotype. Passage 9 ASCs had lost their adipogenic potential, but significantly increased the proportion of SA-β-gal positive (blue-green) cells. (D) Differentiation into adipocytes was confirmed using Oil-Red-O staining, as described in Methods.