Huh 7 cells

Anti‐LRP1 (1:5000) and LDLR antibodies (1:2000) were purchased from Abcam. Secondary antibodies (IRDye 680RD Goat anti‐Rabbit and IRDye 800CW Donkey anti‐Mouse, 1:10 000) and anti‐β‐actin antibody (1:5000) were purchased from LI‐COR Biosciences. For flow cytometry, polyclonal anti‐FVIII antibody (Enzyme Research Laboratories) was conjugated to Alexa Fluor 647 dye (Thermo Fisher Scientific). HepG2, Hep3B, and SK‐HEP1 cells were purchased from American Type Culture Collection (ATCC), and Huh‐7 cells were purchased from Sekisui XenoTech. Cells were cultured according to manufacturer's instructions. Cells were transfected with siRNAs purchased from Dharmacon using DharmaFECT. Protein lysates (40 μg) were prepared as described⁵⁵ from HepG2, Hep3B, Huh‐7, and SK‐HEP1 cells and separated on a 4%–12% NuPAGE Bis‐Tris Protein Gel (Thermo Fisher Scientific). Chameleon Duo Pre‐Stained Protein Ladder (LI‐COR) was used as control. For quantification of LRP1 and LDLR expression, immunoblot band intensities were determined by Image Studio Lite (LI‐COR Biosciences).⁵⁶

HEK 293T (CRL-3216) and Vero E6 cells (CRL-1586) were obtained from ATCC. The Huh7 cells are from Sekisui Xenotech (JCRB0403)—the US distributor for the Japanese Collection of Research Bioresources (JCRB) Cell Bank—which is supported by the Japanese National Institute of Biomedical Innovation. All cells were cultured at 37°C under 5% CO₂ in complete DMEM containing 10% FBS or 2% FBS during viral infection, 10 μ/ml penicillin, and 10 μg/ml streptomycin (GIBCO). DMEM, Opti-MEM, and 0.25% trypsin-EDTA were purchased from Thermo Fisher Scientific. FBS was purchased from R&D Systems.