title: CD36- and GPR120-mediated Ca²⁺ signaling in human taste bud cells mediates differential responses to fatty acids and is altered in obese mice.
abstract: OBJECTIVE
  It is important to increase our understanding of gustatory detection of dietary fat and its contribution to fat preference. We studied the roles of the fat taste receptors CD36 and GPR120 and their interactions via Ca(2+) signaling in fungiform taste bud cells (TBC).
  
  
  METHODS
  We measured Ca(2+) signaling in human TBC, transfected with small interfering RNAs against messenger RNAs encoding CD36 and GPR120 (or control small interfering RNAs). We also studied Ca(2+) signaling in TBC from CD36(-/-) mice and from wild-type lean and obese mice. Additional studies were conducted with mouse enteroendocrine cell line STC-1 that express GPR120 and stably transfected with human CD36. We measured release of serotonin and glucagon-like peptide-1 from human and mice TBC in response to CD36 and GPR120 activation.
  
  
  RESULTS
  High concentrations of linoleic acid induced Ca(2+) signaling via CD36 and GPR120 in human and mice TBC, as well as in STC-1 cells, and low concentrations induced Ca(2+) signaling via only CD36. Incubation of human and mice fungiform TBC with lineoleic acid down-regulated CD36 and up-regulated GPR120 in membrane lipid rafts. Obese mice had decreased spontaneous preference for fat. Fungiform TBC from obese mice had reduced Ca(2+) and serotonin responses, but increased release of glucagon-like peptide-1, along with reduced levels of CD36 and increased levels of GPR120 in lipid rafts.
  
  
  CONCLUSIONS
  CD36 and GPR120 have nonoverlapping roles in TBC signaling during orogustatory perception of dietary lipids; these are differentially regulated by obesity.
authors.affiliation: Monell Chemical Senses Center, Philadelphia, Pennsylvania.
authors.forename: Mehmet Hakan
authors.initials: MH
authors.lastname: Ozdener
authors.affiliation: UMR U866 INSERM, Dijon, France.
authors.forename: Selvakumar
authors.initials: S
authors.lastname: Subramaniam
authors.affiliation: Center for Human Nutrition and Department of Cell Biology and Physiology, Washington University, St Louis, Missouri.
authors.forename: Sinju
authors.initials: S
authors.lastname: Sundaresan
authors.affiliation: Academy of Science, Brno, Czech Republic.
authors.forename: Omar
authors.initials: O
authors.lastname: Sery
authors.affiliation: Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Hashimoto
authors.affiliation: Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Asakawa
authors.affiliation: UMR U866 INSERM, Dijon, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Besnard
authors.affiliation: Center for Human Nutrition and Department of Cell Biology and Physiology, Washington University, St Louis, Missouri.
authors.forename: Nada A
authors.initials: NA
authors.lastname: Abumrad
authors.affiliation: UMR U866 INSERM, Dijon, France. Electronic address: Naim.Khan@u-bourgogne.fr.
authors.forename: Naim Akhtar
authors.initials: NA
authors.lastname: Khan
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D018955:CD36 Antigens / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D020013:Calcium Signaling; D002460:Cell Line; D059305:Diet, High-Fat; D004195:Disease Models, Animal; D005518:Food Preferences; D052216:Glucagon-Like Peptide 1 / Q000378:metabolism; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D019787:Linoleic Acid / Q000378:metabolism*; D021962:Membrane Microdomains / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009765:Obesity / Q000235:genetics / Q000378:metabolism* / Q000523:psychology; D034622:RNA Interference; D043562:Receptors, G-Protein-Coupled / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism; D013649:Taste; D013650:Taste Buds / Q000378:metabolism*; D055697:Taste Perception; D014162:Transfection
chemical_list: D018955:CD36 Antigens; C519853:FFAR4 protein, human; C498007:FFAR4 protein, mouse; D043562:Receptors, G-Protein-Coupled; D012701:Serotonin; D015544:Inositol 1,4,5-Trisphosphate; D052216:Glucagon-Like Peptide 1; D019787:Linoleic Acid
keywords: GLP-1; Linoleic Acid; Lipids; Serotonin