FIGURE 7.
Effects of SMS1 overexpression and palmitic acid on the synthesis of major lipid classes. HepG2-SMS1 and EV control cells were supplemented with [3H]palmitic acid at low (0.1 mm) or high (1.0 mm) concentration for 18 h. The specific labeling in each case was kept at 50 mCi/mmol. Lipids were extracted and separated by TLC as described under “Experimental Procedures.” Radioactivity from the individual bands was quantified by scintillation counting. A, SM; B, TG; C, phosphatidylcholine; D, phosphatidylethanolamine; E, phosphatidylserine; F, phosphatidic acid; G, DG. According to two-way analysis of variance, a strong statistically significant main effect of palmitate treatment was detected for all lipids. The main effects of SMS1 overexpression on TG, PC, and DG were also statistically significant. A statistically significant interaction effect was seen for SM and TG. Results of Bonferroni post-test analyses are shown (*, p < 0.05; **, p < 0.01; ***, p < 0.001). Results were confirmed in two independent experiments. Error bars, S.D.