Fig. 1

PNPT1 silencing does not induce dsRNA accumulation and a type I IFN response in EndoC-βH1 cells. EndoC-βH1 cells were transfected with a siRNA control (siQ: white bars) and two different siRNAs targeting PNPT1 (siP#1: grey bars and siP#2: blue bars) and cells were maintained in culture during 48 h. As a positive control for gene expression, in some experiments cells were treated with IFNα (2000 U/ml) for 24 h (red bars), and as a positive control for dsRNA staining, cells were infected with CVB5 (MOI 5). a Protein expression was measured by western blotting and representative images of 2–9 independent experiments are shown. Densitometry results are shown for PNPT1 (b), pSTAT1 (e), pSTAT2 (f), STAT1 (g) and STAT2 (h). d dsRNA accumulation (red) and the presence of the viral capside protein VP1 (green) for CVB5-infected cells was analyzed by immunocytochemistry. Representative images of 2 (siPNPT1#1) or 3 (siPNPT1#2) independent experiments and images of 1 experiment with CVB5 infection are shown (magnification 40×). mRNA expression of PNPT1 (c), MDA5 (i), HLA-ABC (j), MX1 (k) and CHOP (l) were analyzed by RT-qPCR and normalized by β-actin and then by the value of siQ considered as 1. Results are mean ± SEM of 3–9 independent experiments. *p < 0.05, **p < 0.01 and ***p < 0.001 vs siQ, Student t test