Fig. 3

Downregulation of KLF4 in old hBM-MSCs decreased hypoxia-induced apoptosis and increased cell survival. KLF4 was effectively inhibited in old hBM-MSCs by lentiviral vector (O-antiKLF4). Control vector-transduced old hBM-MSCs (O-c) served as control. Cells cultured for 72 h under hypoxia conditions. a Cell apoptosis assayed by TUNEL staining. Percentage of apoptotic cells (TUNEL⁺) quantified in O-c and O-antiKLF4 hBM-MSCs. b Cell survival evaluated in O-c and O-antiKLF4 hBM-MSCs. c Protein expression of MCL1 and PUMA evaluated by western blot analysis in O-c and O-antiKLF4 hBM-MSCs. d Ratio of Bax/BCL2 quantified in O-c and O-antiKLF4 hBM-MSCs. e Protein expression of cleaved caspase-3 and inhibitor of caspase-activated DNase (ICAD) assayed in O-c and O-antiKLF4 hBM-MSCs. f Caspase-3 activity measured in O-c and O-antiKLF4 hBM-MSCs. n = 6/group. Mean ± SD. *P < 0.05. DAPI 4′,6-diamidino-2-phenylindole, KLF4 Krüpple-like factor 4, TUNEL terminal deoxynucleotidyl transferase dUTP nick end labeling, RFU relative fluorescence units