FIG. 3.

GPR55 regulates lipid accumulation in human hepatocytes through pACC. (A) GPR55 mRNA in THLE2 hepatic cells treated with different doses of LPI (n = 6) (B) Protein levels of markers of lipid metabolism in cells following administration of 10 µM LPI for 6 hours (n = 6). (C) mRNA levels of GPR55 in THLE2 cells transfected with siGPR55 or siCTL for 48 hours (n = 3 per group). Oil Red O staining of THLE2 cells after silencing GPR55, treated with vehicle or LPI. Lipids were quantified and normalized to the total number of nuclei per field (n = 6). Protein levels of pAMPKα, pACC, and ACC were measured (n = 5‐6). (D) Oil Red O staining in THLE2 cells cultured in oleic acid (1 mM) after the down‐regulation of GPR55 (n = 6). (E) mRNA levels of ACCα in THLE2 cells transfected with siACCα or siCTL for 48 hours (n = 5‐6). Oil Red O staining of THLE2 cells after silencing ACCα, treated with vehicle or LPI (n = 6). GAPDH and HPRT were used to normalize protein and mRNA levels. Dividing lines indicate splicing in the same gel. Data are presented as mean ± SEM. Statistical differences are denoted by *P < 0.05, **P < 0.01, and ***P < 0.001. Abbreviations: ACC, acetyl–coenzyme A carboxylase; BSA, bovine serum albumin; CPT1a, carnitine palmitoyl transferase 1a; FAS, Fas cell‐surface death receptor; GAPDH, glyceraldehyde 3‐phosphate dehydrogenase; GPR55, G protein–coupled receptor 55; HPRT, hypoxanthine‐guanine phosphoribosyltransferase; LPI, l‐α‐lysophosphatidylinositol; LPL, lipoprotein lipase; pACC, phosphorylated ACC; pAMPKα, phosphorylated adenosine monophosphate–activated protein kinase α; siACCα, small interfering RNA ACCα; siCTL, small interfering RNA control; siGPR55, small interfering RNA GPR55.