Fig. 3: ATP7B loss leads to elevated PrP expression in hepatic cells.
From: Prion protein promotes copper toxicity in Wilson disease
WT and ATP7B-KO HepG2 cells were treated with 0.5 mM CuCl2 for 24 h and then prepared for qRT-PCR (a) or Western blot (b, c) to assess PRNP/PrP expression levels. Graph in (a) shows that Cu treatment strongly stimulates PRNP expression in ATP7B-KO cells but now in parental WT cell line (Mean ± SD; two-way ANOVA; n = 3 experiments). Prnp/PrP expression was analyzed in the liver of Atp7b−/− mice and control Atp7b+/− mice by qRT-PCR (d), Western blot (e, f), or immuno-histochemistry (g). All three methods demonstrate elevated expression of PrP in the liver of Atp7b−/− mice (Mean ± SD; t-test; n = 4 animals for d, n = 3 animals for f). h Expression levels of PRNP in the healthy or WD-affected human liver tissue were extracted from transcriptomics data published by ref. 38. The graph shows higher expression of PRNP in the WD-affected human liver tissue (Mean ± SD; t-test; n = 4 experiments). i Scheme illustrating the impact of ATP7B loss on PrP expression. In normal liver tissue, ATP7B removes excess Cu from hepatocytes (blue arrow) thereby preventing Cu-dependent induction of PrP expression. Upon ATP7B loss in WD accumulating Cu stimulates PrP expression, which in turn favors further Cu uptake/accumulation (red arrows) leading again to higher PrP expression, thus generating a vicious circle. j Control and MTF1-silenced ATP7B-KO HepG2 were treated with 0.5 mM CuCl2 for 24 h and then prepared for qRT-PCR, which shows that Cu fails to activate PRNP expression in MTF1-silenced cells (Mean ± SD; two way ANOVA; n = 3 experiments). Scale bar: 90 µm (g).
