title: Establishment of a gastric cell-based assay system for exploring inhibitors of octanoylated ghrelin production.
abstract: Ghrelin, a gastric hormone, is a growth hormone-releasing peptide. Its serine-3 acylation with octanoic acid is essential for its orexigenic activity, and therefore, inhibition of the acylation of ghrelin may help in decreasing appetite and preventing obesity. This study aimed to establish a human gastric cell-based assay system to evaluate candidate inhibitors of octanoylated ghrelin production. In human gastric carcinoma AGS cells, obligatory factors for the posttranslational modification of ghrelin, such as certain prohormone convertases responsible for processing of proghrelin to the mature ghrelin and the enzyme-catalyzing acyl-modification of ghrelin, were well expressed, but ghrelin was expressed at low levels. Accordingly, we transfected a ghrelin-expressing vector into AGS cells and isolated a stable ghrelin-expressing cell line (AGS-GHRL8). AGS-GHRL8 cells secreted octanoylated ghrelin in accordance with the concentrations of octanoic acid in the culture medium. Given that ingested heptanoic acid is used for the acyl-modification of ghrelin, we evaluated whether heptanoic acid inhibits production of octanoylated ghrelin in AGS-GHRL8 cells. Butyric acid was used as a control. Indeed, heptanoic acid predictably decreased the secretion of octanoylated ghrelin, whereas butyric acid did not. The AGS-GHRL8 line established in this study will facilitate the screening of inhibitors of octanoylated ghrelin production.
authors.affiliation: 1Department of Pharmaceutical Health Care Sciences, Faculty of Pharmaceutical Sciences, Nagasaki International University, Huis Ten Bosch Sasebo, Nagasaki, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Oiso
authors.forename: Miyuki
authors.initials: M
authors.lastname: Nobe
authors.forename: Yuhei
authors.initials: Y
authors.lastname: Yamaguchi
authors.forename: Shigeru
authors.initials: S
authors.lastname: Umemoto
authors.forename: Kazuo
authors.initials: K
authors.lastname: Nakamura
authors.forename: Hiroko
authors.initials: H
authors.lastname: Kariyazono
mesh_terms: D000215:Acylation; D001681:Biological Assay; D020148:Butyric Acid / Q000494:pharmacology; D002210:Caprylates / Q000378:metabolism* / Q000494:pharmacology; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D005822:Genetic Vectors; D054439:Ghrelin / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006538:Heptanoic Acids / Q000494:pharmacology*; D006801:Humans; D014162:Transfection
chemical_list: D002210:Caprylates; D054439:Ghrelin; D006538:Heptanoic Acids; D020148:Butyric Acid; C031492:octanoic acid
keywords: AGS cells; butyric acid; des-acyl ghrelin; heptanoic acid; octanoylated ghrelin