Fig. 4
NTCP protein modulation in D-UCMSCs. a Western blot analysis of sodium taurocholate cotransporting peptide (NTCP) protein expression in differentiated umbilical cord stem cells (D-UCMSCs): an NTCP 55 kDa band was detected in D-UCMSCs (n = 3). Ninety micrograms of total protein samples were loaded per lane. NTCP was detected by anti-NTCP primary antibody (kind gift from Prof. Bruno Stieger). Actin was used as the loading control. b ICG functional uptake and release assay. D-UCMSCs acquire both the ability to internalize (left panel) and to release ICG (right panel). Pictures were taken at 5 h and at 5 days post-treatment, respectively (magnification 200×) (n = 3). In contrast, naive UCMSCs are not able to either internalise nor release ICG as compared to D-UCMSCs (n = 3). c Taurocholate (TC) uptake assay with and without sodium. Uptake was measured in UCMSCs (n = 2) and D-UCMSCs (n = 3) using increasing concentrations of TC. UCMSCs do not uptake TC efficiently with and without sodium (left panel). D-UCMSCs increase TC uptake function with or without sodium ((Vmax = 1,460 km = 6.180). TC uptake under sodium conditions significantly increased at 1 μM (Vmax = 10,791) as compared to the sodium-free condition (Vmax = 821). Values are expressed as TC uptake (pmol/min/mg protein)