title: Comprehensive Profiling of GPCR Expression in Ghrelin-Producing Cells.
abstract: To determine the comprehensive G protein-coupled receptor (GPCR) expression profile in ghrelin-producing cells and to elucidate the role of GPCR-mediated signaling in the regulation of ghrelin secretion, we determined GPCR expression profiles by RNA sequencing in the ghrelin-producing cell line MGN3-1 and analyzed the effects of ligands for highly expressed receptors on intracellular signaling and ghrelin secretion. Expression of selected GPCRs was confirmed in fluorescence-activated cell-sorted fluorescently tagged ghrelin-producing cells from ghrelin-promoter CreERT2/Rosa-CAG-LSL-ZsGreen1 mice. Expression levels of GPCRs previously suggested to regulate ghrelin secretion including adrenergic-β1 receptor, GPR81, oxytocin receptor, GPR120, and somatostatin receptor 2 were high in MGN3-1 cells. Consistent with previous reports, isoproterenol and oxytocin stimulated the Gs and Gq pathways, respectively, whereas lactate, palmitate, and somatostatin stimulated the Gi pathway, confirming the reliability of current assays. Among other highly expressed GPCRs, prostaglandin E receptor 4 agonist prostaglandin E2 significantly stimulated the Gs pathway and ghrelin secretion. Muscarine, the canonical agonist of cholinergic receptor muscarinic 4, stimulated both the Gq and Gi pathways. Although muscarine treatment alone did not affect ghrelin secretion, it did suppress forskolin-induced ghrelin secretion, suggesting that the cholinergic pathway may play a role in counterbalancing the stimulation of ghrelin by Gs (eg, by adrenaline). In addition, GPR142 ligand tryptophan stimulated ghrelin secretion. In conclusion, we determined the comprehensive expression profile of GPCRs in ghrelin-producing cells and identified two novel ghrelin regulators, prostaglandin E2 and tryptophan. These results will lead to a greater understanding of the physiology of ghrelin and facilitate the development of ghrelin-modulating drugs.
authors.affiliation: Medical Innovation Center (H.I., K.D., M.B., T.K., C.S., K.H., K.K., K.N.) and Departments of Diabetes, Endocrinology, and Nutrition (H.K.) and Human Health Sciences (K.H.), Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan; National Cerebral and Cardiovascular Center Research Institute (H.H., K.K.), Osaka 565-8565; Japan; and The First Department of Medicine (H.A., T.A.), Wakayama Medical University, Wakayama 641-8509, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Koyama
authors.affiliation: Medical Innovation Center (H.I., K.D., M.B., T.K., C.S., K.H., K.K., K.N.) and Departments of Diabetes, Endocrinology, and Nutrition (H.K.) and Human Health Sciences (K.H.), Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan; National Cerebral and Cardiovascular Center Research Institute (H.H., K.K.), Osaka 565-8565; Japan; and The First Department of Medicine (H.A., T.A.), Wakayama Medical University, Wakayama 641-8509, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iwakura
authors.affiliation: Medical Innovation Center (H.I., K.D., M.B., T.K., C.S., K.H., K.K., K.N.) and Departments of Diabetes, Endocrinology, and Nutrition (H.K.) and Human Health Sciences (K.H.), Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan; National Cerebral and Cardiovascular Center Research Institute (H.H., K.K.), Osaka 565-8565; Japan; and The First Department of Medicine (H.A., T.A.), Wakayama Medical University, Wakayama 641-8509, Japan.
authors.forename: Katsuko
authors.initials: K
authors.lastname: Dote
authors.affiliation: Medical Innovation Center (H.I., K.D., M.B., T.K., C.S., K.H., K.K., K.N.) and Departments of Diabetes, Endocrinology, and Nutrition (H.K.) and Human Health Sciences (K.H.), Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan; National Cerebral and Cardiovascular Center Research Institute (H.H., K.K.), Osaka 565-8565; Japan; and The First Department of Medicine (H.A., T.A.), Wakayama Medical University, Wakayama 641-8509, Japan.
authors.forename: Mika
authors.initials: M
authors.lastname: Bando
authors.affiliation: Medical Innovation Center (H.I., K.D., M.B., T.K., C.S., K.H., K.K., K.N.) and Departments of Diabetes, Endocrinology, and Nutrition (H.K.) and Human Health Sciences (K.H.), Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan; National Cerebral and Cardiovascular Center Research Institute (H.H., K.K.), Osaka 565-8565; Japan; and The First Department of Medicine (H.A., T.A.), Wakayama Medical University, Wakayama 641-8509, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hosoda
authors.affiliation: Medical Innovation Center (H.I., K.D., M.B., T.K., C.S., K.H., K.K., K.N.) and Departments of Diabetes, Endocrinology, and Nutrition (H.K.) and Human Health Sciences (K.H.), Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan; National Cerebral and Cardiovascular Center Research Institute (H.H., K.K.), Osaka 565-8565; Japan; and The First Department of Medicine (H.A., T.A.), Wakayama Medical University, Wakayama 641-8509, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ariyasu
authors.affiliation: Medical Innovation Center (H.I., K.D., M.B., T.K., C.S., K.H., K.K., K.N.) and Departments of Diabetes, Endocrinology, and Nutrition (H.K.) and Human Health Sciences (K.H.), Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan; National Cerebral and Cardiovascular Center Research Institute (H.H., K.K.), Osaka 565-8565; Japan; and The First Department of Medicine (H.A., T.A.), Wakayama Medical University, Wakayama 641-8509, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Kusakabe
authors.affiliation: Medical Innovation Center (H.I., K.D., M.B., T.K., C.S., K.H., K.K., K.N.) and Departments of Diabetes, Endocrinology, and Nutrition (H.K.) and Human Health Sciences (K.H.), Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan; National Cerebral and Cardiovascular Center Research Institute (H.H., K.K.), Osaka 565-8565; Japan; and The First Department of Medicine (H.A., T.A.), Wakayama Medical University, Wakayama 641-8509, Japan.
authors.forename: Choel
authors.initials: C
authors.lastname: Son
authors.affiliation: Medical Innovation Center (H.I., K.D., M.B., T.K., C.S., K.H., K.K., K.N.) and Departments of Diabetes, Endocrinology, and Nutrition (H.K.) and Human Health Sciences (K.H.), Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan; National Cerebral and Cardiovascular Center Research Institute (H.H., K.K.), Osaka 565-8565; Japan; and The First Department of Medicine (H.A., T.A.), Wakayama Medical University, Wakayama 641-8509, Japan.
authors.forename: Kiminori
authors.initials: K
authors.lastname: Hosoda
authors.affiliation: Medical Innovation Center (H.I., K.D., M.B., T.K., C.S., K.H., K.K., K.N.) and Departments of Diabetes, Endocrinology, and Nutrition (H.K.) and Human Health Sciences (K.H.), Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan; National Cerebral and Cardiovascular Center Research Institute (H.H., K.K.), Osaka 565-8565; Japan; and The First Department of Medicine (H.A., T.A.), Wakayama Medical University, Wakayama 641-8509, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Akamizu
authors.affiliation: Medical Innovation Center (H.I., K.D., M.B., T.K., C.S., K.H., K.K., K.N.) and Departments of Diabetes, Endocrinology, and Nutrition (H.K.) and Human Health Sciences (K.H.), Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan; National Cerebral and Cardiovascular Center Research Institute (H.H., K.K.), Osaka 565-8565; Japan; and The First Department of Medicine (H.A., T.A.), Wakayama Medical University, Wakayama 641-8509, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kangawa
authors.affiliation: Medical Innovation Center (H.I., K.D., M.B., T.K., C.S., K.H., K.K., K.N.) and Departments of Diabetes, Endocrinology, and Nutrition (H.K.) and Human Health Sciences (K.H.), Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan; National Cerebral and Cardiovascular Center Research Institute (H.H., K.K.), Osaka 565-8565; Japan; and The First Department of Medicine (H.A., T.A.), Wakayama Medical University, Wakayama 641-8509, Japan.
authors.forename: Kazuwa
authors.initials: K
authors.lastname: Nakao
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D045744:Cell Line, Tumor; D005576:Colforsin / Q000494:pharmacology; D015232:Dinoprostone / Q000494:pharmacology; D005753:Gastric Mucosa / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D020869:Gene Expression Profiling; D054439:Ghrelin / Q000187:drug effects / Q000378:metabolism*; D006728:Hormones / Q000494:pharmacology; D007150:Immunohistochemistry; D007545:Isoproterenol / Q000494:pharmacology; D019344:Lactic Acid / Q000494:pharmacology; D051379:Mice; D008822:Mice, Transgenic; D009116:Muscarine / Q000494:pharmacology; D018721:Muscarinic Agonists / Q000494:pharmacology; D010120:Oxytocics / Q000494:pharmacology; D010121:Oxytocin / Q000494:pharmacology; D010168:Palmitates / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism*; D043588:Receptor, Muscarinic M4 / Q000819:agonists; D018342:Receptors, Adrenergic, beta-1 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D018045:Receptors, Oxytocin / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D058309:Receptors, Prostaglandin E, EP4 Subtype / Q000819:agonists; D017481:Receptors, Somatostatin / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D017423:Sequence Analysis, RNA; D013004:Somatostatin / Q000494:pharmacology; D014364:Tryptophan / Q000494:pharmacology
chemical_list: D000318:Adrenergic beta-Agonists; C498007:FFAR4 protein, mouse; D054439:Ghrelin; C529424:Hcar1 protein, mouse; D006728:Hormones; D018721:Muscarinic Agonists; C576074:OXTR protein, mouse; D010120:Oxytocics; D010168:Palmitates; D012333:RNA, Messenger; D043588:Receptor, Muscarinic M4; D018342:Receptors, Adrenergic, beta-1; D043562:Receptors, G-Protein-Coupled; D018045:Receptors, Oxytocin; D058309:Receptors, Prostaglandin E, EP4 Subtype; D017481:Receptors, Somatostatin; C570769:somatostatin receptor 2, mouse; D005576:Colforsin; D019344:Lactic Acid; D010121:Oxytocin; D013004:Somatostatin; D009116:Muscarine; D014364:Tryptophan; D015232:Dinoprostone; D007545:Isoproterenol