Fig. 1: Differential sensitivity to tBid-induced cyto c release and ∆ψm loss in primary hepatocytes and liver cancer cell lines.
A Representative time-lapse imaging of TMRE-loaded permeabilized HepG2 and primary rat and human hepatocytes before and 600 s after treatment with truncated Bid (tBid) (25 nM) (Upper panels). Plots (lower panels) show the mean TMRE fluorescence of the cell population in the imaging field. Chemical uncoupler, FCCP (5 µM), was added at the end of each run to fully depolarize the mitochondria. Experiments were repeated three times with similar results. B Representative immunoblots of permeabilized cell suspensions of equal cellular protein aliquots were treated with 25 nM tBid or with 600 μg/ml digitonin for 10 min. Cyto c release from the mitochondria assayed by rapidly separating membrane and cytosolic fractions (upper and lower panels, respectively). Experiments were repeated three times with similar results. C Representative time lapse recordings of ΔΨm in permeabilized cell suspensions by TMRE dequenching. HepG2 and PLC cells and primary human hepatocytes were treated with tBid at the indicated concentrations. Digitonin (600 μg/ml) was added to human hepatocytes as a positive control. Experiments were repeated three times with similar results. D Representative ΔΨm traces of isolated HepG2 mitochondria treated with varying concentrations of tBid measured by Rhod123 quenching (upper panel). Western blot shows the release of cyto c in the supernatant fraction following treatment (lower panel). Experiments were repeated three times with similar results. E Representative ΔΨm traces of isolated mitochondria from rat and mouse liver treated with tBid (25 nM) or oligomeric Bax (150 nM) and western blots of released cyto c from the same experiments. Experiments were repeated three times with similar results. Source data are provided in the Source Data file.
