Figure 4. Bile acids induce PA production.

(A) HepG2 cells were treated with 1 nM GW4064 and R59949 from 24 h to 72 h and PA levels were quantified by ELISA. (B) Lysates from wild-type (wt) and DGKθ-knockdown (DGKq^kd) cells were harvested and analysed using SDS/PAGE and Western blotting using anti-DGKθ (top) and anti-GAPDH (bottom) antibodies. DGKθ mRNA expression was quantified in wild-type and DGKθ-knockdown HepG2 cells by qRT-PCR (quantitative reverse transcription–PCR). Data are shown as fold change in DGKθ mRNA expression and normalized to β-actin mRNA expression. (C) Wild-type and DGKθ-knockdown cells were treated with 1 nM GW4064 and the cellular amount of PA was measured and normalized to the protein concentration. (D) HepG2 cells and DGKθ-knockdown HepG2 cells were treated with 1 nM GW4064 for 72 h. Cellular DAG levels were measured by ELISA kit. The graph shows the means ± S.E.M. for three separate experiments, each performed in triplicate. *P < 0.05 indicate a statistically significant difference from the untreated wild-type control group. Human hepatocytes from donor 4 were cultured on to six-well plates and incubated with 1 nM GW4064 for 72 h. Cellular PA (E) and DAG (F) concentration were quantified by PA assay and DAG assay respectively. *P < 0.05, a statistically significant difference from the untreated control group.