Figure 3.

HLCs express low levels of TLR3 but can respond to viral ligand stimulation. (a) Comparison of baseline TLR3 mRNA expression in PHH, P106-iPSCs, and P106 HLCs on d20. Gene-expression was determined by qPCR, normalised to b2m, and compared to PRR gene-expression in PHHs. iPSCs expressed high levels of TLR3 mRNA, while levels in HLCs were lower compared with PHHs (N = 3). (b) P106-HLCs mount strong innate immune responses upon activation of TLR3 by polyI:C stimulation. PolyI:C stimulation induced type I and III IFN expression in a time-dependent manner, as determined by qPCR, and IFNs further induced ISG-expression (ISG15, Mx1) (N = 3). (c) Expression of CXCL10 protein upon stimulation with polyI:C. As determined by ELISA 24 h after stimulation, polyI:C induced the expression CXCL10 protein, although this was not significant (N = 3). (d) Effect of innate immune activation on hepatocytes metabolic activity. Cells were treated with polyI:C for 16 h before CYP-activity and plasma protein production was measured and compared to unstimulated cells. The generation of an inflammatory environment induced downregulation of AFP, ALB, and CYP1A2, while innate immune responses were activated (N = 3). Results are shown as mean +/− SEM. *p < 0.05, and ***p < 0.001. PHH = primary human hepatocytes, TLR3 = Toll-like receptor 3, HLCs = hepatocyte like cells. S = stimulation, IFN = interferon, ISG = Interferon stimulated genes, CXCL10 = C-X-C motif chemokine 10, AFP = alfa fetoprotein, ALB = albumin, CYP = cytochrome P450.