(20 ng/mL; PeproTech) for 5 days in 5% oxygen/5% CO2, yielding immature HLCs; and (4) HCM Hepatocyte Culture Medium (Lonza) without EGF and supplemented with recombinant human oncostatin M (20 ng/mL; R&D Systems) for 5 days in ambient oxygen/5% CO2, yielding mature HLCs. A subset of HLC samples were assessed with DAPI and immunofluorescence with an HNF-4α antibody (Santa Cruz Biotechnology). RNA-seq data (see below) confirmed the expression of hepatocyte-specific genes in the HLC samples. ApoB, triglyceride, and albumin secreted into the media by HLCs were measured with the Human apoB ELISAPRO kit (Mabtech), Infinity Triglycerides Reagent (Thermo Fisher Scientific), and Human Albumin ELISA Quantitation Set (Bethyl Laboratories) according to the manufacturers’ instructions.
