title: Myristic Acid Enhances Diacylglycerol Kinase δ-Dependent Glucose Uptake in Myotubes.
abstract: Decreased expression of diacylglycerol kinase (DGK) δ in skeletal muscles attenuates glucose uptake and is closely related to the pathogenesis of type 2 diabetes. Therefore, up-regulation of DGKδ expression is thought to protect and improve glucose homoeostasis in type 2 diabetes. We recently determined that myristic acid (14:0), but not palmitic (16:0) or stearic (18:0) acid, significantly increased DGKδ2 protein expression in mouse C2C12 myotubes. In the current study, we analyzed whether myristic acid indeed enhances glucose uptake in C2C12 myotubes. We observed that myristic acid caused ~1.4-fold increase in insulin-independent glucose uptake. However, palmitic and stearic acids failed to enhance glucose uptake. DGKδ-specific siRNA decreased myristic acid-dependent increase of glucose uptake. Moreover, overexpression of DGKδ2 enhanced glucose uptake in C2C12 cells in the absence of myristic acid treatment. Taken together, these results strongly suggest that myristic acid enhances basal glucose uptake in myotubes in a DGKδ2 expression-dependent manner.
authors.affiliation: Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Wada
authors.affiliation: Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan.
authors.forename: Shizuka
authors.initials: S
authors.lastname: Sakiyama
authors.affiliation: Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan.
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Sakai
authors.affiliation: Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan. sakane@faculty.chiba-u.jp.
authors.forename: Fumio
authors.initials: F
authors.lastname: Sakane
mesh_terms: D000818:Animals; D002460:Cell Line; D019852:Diacylglycerol Kinase / Q000235:genetics / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D005947:Glucose / Q000378:metabolism*; D051379:Mice; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000378:metabolism*; D019814:Myristic Acid / Q000494:pharmacology*; D019308:Palmitic Acid / Q000494:pharmacology; D013229:Stearic Acids / Q000494:pharmacology
chemical_list: D013229:Stearic Acids; D019814:Myristic Acid; D019308:Palmitic Acid; D019852:Diacylglycerol Kinase; D005947:Glucose
keywords: Diacylglycerol kinase; Expression regulation; Fatty acid; Glucose uptake; Myristic acid; Type 2 diabetes