title: Pinolenic Acid Downregulates Lipid Anabolic Pathway in HepG2 Cells.
abstract: Pine nut oil (PNO) was reported to reduce lipid accumulation in the liver. However, the specific effect of pinolenic acid (18:3, all-cis-Δ5,9,12), a unique component of PNO, on lipid metabolism has not been studied. We hypothesized that pinolenic acid downregulates the lipid anabolic pathway in HepG2 cells. HepG2 cells were incubated in serum-free medium supplemented with 50 μM bovine serum albumin (BSA), palmitic acid, oleic acid, γ-linolenic acid, pinolenic acid, eicosapentaenoic acid (EPA), or α-linolenic acid for 24 h. Lipid accumulation was determined by Oil Red O (ORO) staining. The mRNA levels of genes related to fatty acid biosynthesis (SREBP1c, FAS, SCD1, and ACC1), fatty acid oxidation (ACC2, PPARα, CPT1A, and ACADL), cholesterol synthesis (SREBP2 and HMGCR), and lipoprotein uptake (LDLr) and of genes that may be involved in the downregulation of the lipogenic pathway (ACSL3, ACSL4, and ACSL5) were determined by qPCR. LDLR protein levels were measured by Western blot analysis. The mRNA levels of SREBP1c, FAS, and SCD1 were significantly downregulated by pinolenic acid treatment compared to BSA control (53, 54, and 38 % lower, respectively). In addition, the mRNA levels of HMGCR, ACSL3, and LDLr were significantly lower (30, 30, and 43 % lower, respectively), and ACSL4 tended to be lower in the pinolenic acid group (20 % lower, P = 0.082) relative to the control group. In conclusion, pinolenic acid downregulated the lipid anabolic pathway in HepG2 cells by reducing expression of genes related to lipid synthesis, lipoprotein uptake, and the regulation of the lipogenic pathway.
authors.affiliation: Department of Food and Nutrition, College of Human Ecology, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea.
authors.forename: Ah Ron
authors.initials: AR
authors.lastname: Lee
authors.affiliation: Department of Food and Nutrition, College of Human Ecology, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea. snhan@snu.ac.kr.|Research Institute of Human Ecology, College of Human Ecology, Seoul National University, Seoul, Korea. snhan@snu.ac.kr.
authors.forename: Sung Nim
authors.initials: SN
authors.lastname: Han
mesh_terms: D053898:Biosynthetic Pathways / Q000187:drug effects*; D015536:Down-Regulation; D005786:Gene Expression Regulation / Q000187:drug effects; D056945:Hep G2 Cells; D006801:Humans; D008042:Linolenic Acids / Q000494:pharmacology*; D050356:Lipid Metabolism / Q000187:drug effects*; D008074:Lipoproteins / Q000378:metabolism*; D011973:Receptors, LDL / Q000235:genetics; D013230:Stearoyl-CoA Desaturase / Q000235:genetics; D051780:Sterol Regulatory Element Binding Protein 1 / Q000235:genetics; D019014:fas Receptor / Q000235:genetics
chemical_list: C491901:FAS protein, human; C573412:LDLR protein, human; D008042:Linolenic Acids; D008074:Lipoproteins; D011973:Receptors, LDL; C497387:SREBF1 protein, human; D051780:Sterol Regulatory Element Binding Protein 1; D019014:fas Receptor; C034302:5,9,12-octadecatrienoic acid; C523776:SCD1 protein, human; D013230:Stearoyl-CoA Desaturase
keywords: HepG2; Lipid metabolism; Pinolenic acid