title: TRPM5 is critical for linoleic acid-induced CCK secretion from the enteroendocrine cell line, STC-1.
abstract: Fatty acid-induced stimulation of enteroendocrine cells leads to release of the hormones such as cholecystokinin (CCK) that contribute to satiety. Recently, the fatty acid activated G protein-coupled receptor GPR120 has been shown to mediate long-chain unsaturated free fatty acid-induced CCK release from the enteroendocrine cell line, STC-1, yet the downstream signaling pathway remains unclear. Here we show that linoleic acid (LA) elicits membrane depolarization and an intracellular calcium rise in STC-1 cells and that these responses are significantly reduced when activity of G proteins or phospholipase C is blocked. LA leads to activation of monovalent cation-specific transient receptor potential channel type M5 (TRPM5) in STC-1 cells. LA-induced TRPM5 currents are significantly reduced when expression of TRPM5 or GPR120 is reduced using RNA interference. Furthermore, the LA-induced rise in intracellular calcium and CCK secretion is greatly diminished when expression of TRPM5 channels is reduced using RNA interference, consistent with a role of TRPM5 in LA-induced CCK secretion in STC-1 cells.
authors: Department of Biology, Utah State University, Logan, Utah 84322, USA.
authors: Bhavik P
authors: BP
authors: Shah
authors: Pin
authors: P
authors: Liu
authors: Tian
authors: T
authors: Yu
authors: Dane R
authors: DR
authors: Hansen
authors: Timothy A
authors: TA
authors: Gilbertson
mesh_terms: D000818:Animals; D002118:Calcium / Q000037:antagonists & inhibitors / Q000378:metabolism; D045744:Cell Line, Tumor; D016764:Cell Polarity / Q000235:genetics / Q000502:physiology; D002766:Cholecystokinin / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015536:Down-Regulation / Q000235:genetics; D019858:Enteroendocrine Cells / Q000187:drug effects / Q000378:metabolism*; D019787:Linoleic Acid / Q000037:antagonists & inhibitors / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D051379:Mice; D008822:Mice, Transgenic; D034622:RNA Interference / Q000502:physiology; D050053:TRPM Cation Channels / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D015854:Up-Regulation / Q000235:genetics
chemical_list: D050053:TRPM Cation Channels; C498617:Trpm5 protein, mouse; D002766:Cholecystokinin; D019787:Linoleic Acid; D002118:Calcium