Figure 5.
TGF-β signalling delays neurosphere growth and induces the apoptosis of neural stem/progenitor cells. The mean ± SD is shown. The p-value was determined using the Mann–Whitney U-test (A, C and D) and Student's t-test (B). Scale bars = 10 µm.
A. Absolute number of cells in neurosphere cultures in the presence of TGF-β1 (10 ng/ml) at each passage (†cultures stopped at the fourth passage) or in which TGF-β1 was removed after the first passage.
B. Neurosphere size 7 days following the addition of different concentrations of TGF-β1.
C. The phosphorylation of Smad3 following the addition of TGF-β1, and the reversal of this effect by blocking with an anti-TGF-β antibody or SB-505124. The histogram represents the quantifications of the western blots, with normalization to total Smad2/3. Source data is available for this figure in the Supporting Information.
D. Dying cells (permeable for propidium iodide) were quantified by FACS.
E,F. P-Smad3, p21waf and cyclin D1 were induced in neurospheres following TGF-β1 addition.
G,H. Cleaved caspase 3 staining and pyknotic nuclei revealed apoptotic cells in neurospheres that were treated for 24 h with TGF-β1.