GPR52 accelerates fatty acid biosynthesis in a ligand-dependent manner in hepatocytes and in response to excessive fat intake in mice
Mitsuo Wada,
Kayo Yukawa,
Hiroyuki Ogasawara,
Koichi Suzawa,
Tatsuya Maekawa,
Yoshihisa Yamamoto,
Takeshi Ohta,
Eunyoung Lee,
Takashi Miki
Affiliations
Mitsuo Wada
Department of Medical Physiology, Chiba University, Graduate School of Medicine, Chiba 260-8670, Japan; Pharmaceutical Frontier Research Laboratories, Central Pharmaceutical Research Institute, Japan Tobacco Inc., Yokohama 236-0004, Japan
Kayo Yukawa
Pharmaceutical Frontier Research Laboratories, Central Pharmaceutical Research Institute, Japan Tobacco Inc., Yokohama 236-0004, Japan
Hiroyuki Ogasawara
Pharmaceutical Frontier Research Laboratories, Central Pharmaceutical Research Institute, Japan Tobacco Inc., Yokohama 236-0004, Japan
Koichi Suzawa
Central Pharmaceutical Research Institute, Japan Tobacco Inc., Takatsuki 569-1125, Japan
Tatsuya Maekawa
Central Pharmaceutical Research Institute, Japan Tobacco Inc., Takatsuki 569-1125, Japan
Yoshihisa Yamamoto
Pharmaceutical Frontier Research Laboratories, Central Pharmaceutical Research Institute, Japan Tobacco Inc., Yokohama 236-0004, Japan
Takeshi Ohta
Laboratory of Animal Physiology and Functional Anatomy, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
Eunyoung Lee
Department of Medical Physiology, Chiba University, Graduate School of Medicine, Chiba 260-8670, Japan
Takashi Miki
Department of Medical Physiology, Chiba University, Graduate School of Medicine, Chiba 260-8670, Japan; Corresponding author
Summary: Gpr52 is an orphan G-protein-coupled receptor of unknown physiological function. We found that Gpr52-deficient (Gpr52−/−) mice exhibit leanness associated with reduced liver weight, decreased hepatic de novo lipogenesis, and enhanced insulin sensitivity. Treatment of the hepatoma cell line HepG2 cells with c11, the synthetic GPR52 agonist, increased fatty acid biosynthesis, and GPR52 knockdown (KD) abolished the lipogenic action of c11. In addition, c11 induced the expressions of lipogenic enzymes (SCD1 and ELOVL6), whereas these inductions were attenuated by GPR52-KD. In contrast, cholesterol biosynthesis was not increased by c11, but its basal level was significantly suppressed by GPR52-KD. High-fat diet (HFD)-induced increase in hepatic expression of Pparg2 and its targets (Scd1 and Elovl6) was absent in Gpr52−/− mice with alleviated hepatosteatosis. Our present study showed that hepatic GPR52 promotes the biosynthesis of fatty acid and cholesterol in a ligand-dependent and a constitutive manner, respectively, and Gpr52 participates in HFD-induced fatty acid synthesis in liver.
