Fig. 1: ITGB1 heterodimerises with α-integrins in a cell type-dependent manner and mediates nHEV but not eHEV cell.

(A) Heat map showing log2-transformed expression levels of selected integrins in uninfected liver cell lines determined by mass-spectrometry-based proteomics (lower panel, n = 3). Protein levels not detected in at least two replicates were excluded (represented by an X). Cell lines were infected with density gradient-purified nHEV (MOI = 0.1 GE/cell) and infectivity was assessed by staining against HEV ORF2 protein and quantifying FFUs 5 days post-infection (upper panel). n = 9 replicates. (B) Western blot (WB) analysis of hepatoma cell lines and PHH lysates. (C) WB analysis of Huh-7 ITGA2 WT and KO cell lysates. (D) Huh-7 ITGA2 WT and KO cells were infected with nHEV (MOI = 0.1 GE/cell). Infectivity was assessed as in (A). n = 8 replicates. (E) Huh-7 cells were infected with nHEV (MOI = 0.1 GE/cell) in the presence of an integrin α2β1 inhibitor BTT3033 or DMSO. Infectivity was assessed as in (A). n = 9 replicates. (F) WB analysis of S10-3 ITGB1 WT and KO cell lysates. (G) S10-3 ITGB1 WT and KO cells were infected with nHEV (MOI = 0.1 GE/cell) or eHEV particles (MOI = 5 GE/cell). Infectivity was assessed as in (A). n = 6 replicates. (H) S10-3 ITGB1 WT and KO cells were electroporated with an HEV-Gaussia luciferase (GLuc) replicon and HEV replication was quantified by measuring GLuc activity in the supernatant during days 1 to 4 post-electroporation. n = 4 replicates. (I) and (J) S10-3 WT cells were infected with nHEV (MOI = 0.1 GE/cell, n = 6) or eHEV particles (MOI = 5 GE/cell, n = 4) in the presence of an RGD-containing peptide or a scrambled (SCR) control peptide. Infectivity was assessed as in (A). All replicates are from two (B, H, J) or three (A, C, D, E, F, G, I) independent experiments. Statistical analysis was performed by one-way (D, E, G) or two-way ANOVA (I, J). *: p < 0.05; ****: p < 0.0001; ns, non-significant.