Figure 6. Physiological effects of bile salts on human serum and LPA receptor activation.

(a) Inhibition of lysoPLD activity is human serum supplemented by TUDCA, measured as released choline by LPC(18:1) hydrolysis. The error bars represent s.e.m. from three different samples. (b) Representative confocal images of untreated and TUDCA-treated HeLa cells transfected with GFP-LPA₁; the number of GFP-LPA₁-containing endosomes is lower in TUDCA-treated cells. Scale bar, 10 μm. (c) Quantification of LPA₁ internalization shows that TUDCA reduces the number of endosomes compared with untreated cells; error bars correspond to s.e.m. from 27 images in two independent experiments; ***P<0.001 according to Student's t-test.