Figure 3

In vitro hepatocyte lipid accumulation is induced by BMP signaling and is prevented by BMP inhibition. Treatment of HepG2 cells (grown in media containing 1.2 mM oleic acid (OA)) for 24 h with increasing concentrations of LDN-193189 had reduced intracellular lipid content compared to vehicle-treated cells as assessed by measurement of Oil-Red-O staining normalized to total protein content (A, 10 replicates per group). Similarly, HepG2 cells (grown in media containing OA) treated with BMP2 (20 ng/ml) had increased intracellular lipid content and this induction was reversed by co-treatment with LDN-193189 (B, six replicates per group). Treatment of HepG2 cells with OA for 4 h or 24 h, compared to control cells treated for the same durations with bovine serum albumin (BSA) induced mRNA expression of ID1 (inhibitor of DNA binding 1) in HepG2 cells (C, six replicates per group). Similarly, incubation of HepG2 cells with OA also induced DGAT2 (diacylglycerol O-acyltransferase 2) expression at 4 h and 24 h (D, six replicates per group). ID1 and DGAT2 expression were both inhibited by treatment with LDN-193189 in HepG2 cells (E, six replicates per group). Comparisons were performed using the 1-way ANOVA with Sidak’s multiple comparison testing for (A,B) and two-tailed Student’s t test for (C–E).