Fig. 4.

Baseline SOCS1 expression decreases as iPSCs differentiate to HLCs that display ISGylation.

(A) Direct comparison of protein expression for ISG15, ISGylation, UBE1L, UBE2L6, pSTAT1, STAT1, SOCS1, OCT4, ALB and β-actin in iPSCs and HLCs. Cells were treated with 1,000 U/ml of IFNα for 24 h. (B) qPCR data for SOCS1 mRNA basal level expression in iPSCs, DEs, HBs and HLCs (left panel) and in iPSCs and HLCs with and without 8 h of IFNα treatment (right panel). (C) qPCR data for mRNA expression of ISG15, UBE1L, UBE2L6 and STAT1 in iPSCs and HLCs 8 h post IFNα treatment. Data from repeated experiments in triplicate were averaged and are expressed as mean and standard deviation values (error bar) presented with an unpaired Student’s t test with Welch’s correction used to determine the p values. A p value <0.05 was considered significant. ∗p <0.05, ∗∗p <0.001, ∗∗∗p <0.0001, n.s., non-significant. (D) Protein expression for ISG15, ISGylation, UBE1L, UBE2L6, SOCS1, pSTAT1, STAT1, β-actin and ALB following 72 h of transfection of 1 μg control or SOCS1 expression plasmid (P=plasmid) with 1,000 U/ml of IFNα for 24 h. (E) qPCR data for mRNA expression of ISG15, SOCS1, UBE1L, UBE2L6 and STAT1 with corresponding conditions as found in panel D. Data from repeated experiments in triplicate were averaged and are expressed as mean and standard deviation values (error bar) presented with an unpaired Student’s t test with Welch’s correction used to determine the p values. A p value <0.05 was considered significant. ∗p <0.05, ∗∗p <0.001, ∗∗∗p <0.0001, n.s., non-significant.