title: Expression mechanism of tryptophan hydroxylase 1 in mouse islets during pregnancy.
abstract: Serotonin signaling plays key roles in augmentation of pancreatic β-cell function during pregnancy. Increased expression of tryptophan hydroxylase 1 (Tph1), a rate-limiting enzyme for serotonin synthesis by lactogenic hormones, is involved in this phenomenon. To investigate its mechanisms, we here performed 5'-RACE and identified β-cell-specific transcription initiation sites for Tph1. Prolactin enhanced the expression of mRNA containing these exons; however, reporter gene plasmids containing the proximal 5'-flanking region of these exons did not show prolactin responsiveness in MIN6 cells. Prolactin-induced Tph1 expression was inhibited by a Jak2 inhibitor and was partially inhibited by an MEK1/2 or PI3K inhibitor. Therefore, we analyzed interferon γ-activated sequences (GAS) and found GAS-A about 9-kbp upstream of the transcription start site. The reporter gene plasmid containing the GAS-A region linked to a heterologous promoter showed increased promoter activity by prolactin, which was inhibited by the forced expression of a dominant-negative mutant form of Stat5A and a Jak2 inhibitor. Chromatin immunoprecipitation analysis showed that prolactin treatment augmented Stat5 binding to the GAS-A region in MIN6 cells, as well as in isolated mouse islets, and that Stat5 recognized the GAS-A region in pregnant mouse islets. In addition, the transactivation activity of Stat5 was enhanced by prolactin through the Erk and PI3K pathways in MIN6 cells. Finally, serotonin expression was attenuated in islets of β-cell-specific Stat5-deficient mice compared with that of control littermates during pregnancy. Our findings suggest that prolactin-induced Tph1 expression is mediated by the activation of Jak2/Stat5, Erk, and PI3K pathways in β cells.
authors.affiliation: Department of Metabolism and EndocrinologyCenter for Molecular DiabetologyCenter for Therapeutic Innovations in DiabetesJapan Science and Technology Agency-Core Research for Evolutionary Science and Technology ProgramJuntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, JapanGraduate School of Medical Science and EngineeringKorea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of KoreaDiabetes Therapeutics and Research CenterTokushima University, Tokushima 770-8503, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Iida
authors.affiliation: Department of Metabolism and EndocrinologyCenter for Molecular DiabetologyCenter for Therapeutic Innovations in DiabetesJapan Science and Technology Agency-Core Research for Evolutionary Science and Technology ProgramJuntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, JapanGraduate School of Medical Science and EngineeringKorea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of KoreaDiabetes Therapeutics and Research CenterTokushima University, Tokushima 770-8503, Japan take@juntendo.ac.jp.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ogihara
authors.affiliation: Department of Metabolism and EndocrinologyCenter for Molecular DiabetologyCenter for Therapeutic Innovations in DiabetesJapan Science and Technology Agency-Core Research for Evolutionary Science and Technology ProgramJuntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, JapanGraduate School of Medical Science and EngineeringKorea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of KoreaDiabetes Therapeutics and Research CenterTokushima University, Tokushima 770-8503, Japan.
authors.forename: Mun-kyeong
authors.initials: MK
authors.lastname: Min
authors.affiliation: Department of Metabolism and EndocrinologyCenter for Molecular DiabetologyCenter for Therapeutic Innovations in DiabetesJapan Science and Technology Agency-Core Research for Evolutionary Science and Technology ProgramJuntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, JapanGraduate School of Medical Science and EngineeringKorea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of KoreaDiabetes Therapeutics and Research CenterTokushima University, Tokushima 770-8503, Japan.
authors.forename: Akemi
authors.initials: A
authors.lastname: Hara
authors.affiliation: Department of Metabolism and EndocrinologyCenter for Molecular DiabetologyCenter for Therapeutic Innovations in DiabetesJapan Science and Technology Agency-Core Research for Evolutionary Science and Technology ProgramJuntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, JapanGraduate School of Medical Science and EngineeringKorea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of KoreaDiabetes Therapeutics and Research CenterTokushima University, Tokushima 770-8503, Japan.
authors.forename: Yeong Gi
authors.initials: YG
authors.lastname: Kim
authors.affiliation: Department of Metabolism and EndocrinologyCenter for Molecular DiabetologyCenter for Therapeutic Innovations in DiabetesJapan Science and Technology Agency-Core Research for Evolutionary Science and Technology ProgramJuntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, JapanGraduate School of Medical Science and EngineeringKorea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of KoreaDiabetes Therapeutics and Research CenterTokushima University, Tokushima 770-8503, Japan.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Fujimaki
authors.affiliation: Department of Metabolism and EndocrinologyCenter for Molecular DiabetologyCenter for Therapeutic Innovations in DiabetesJapan Science and Technology Agency-Core Research for Evolutionary Science and Technology ProgramJuntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, JapanGraduate School of Medical Science and EngineeringKorea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of KoreaDiabetes Therapeutics and Research CenterTokushima University, Tokushima 770-8503, Japan.
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Tamaki
authors.affiliation: Department of Metabolism and EndocrinologyCenter for Molecular DiabetologyCenter for Therapeutic Innovations in DiabetesJapan Science and Technology Agency-Core Research for Evolutionary Science and Technology ProgramJuntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, JapanGraduate School of Medical Science and EngineeringKorea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of KoreaDiabetes Therapeutics and Research CenterTokushima University, Tokushima 770-8503, Japan Department of Metabolism and EndocrinologyCenter for Molecular DiabetologyCenter for Therapeutic Innovations in DiabetesJapan Science and Technology Agency-Core Research for Evolutionary Science and Technology ProgramJuntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, JapanGraduate School of Medical Science and EngineeringKorea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of KoreaDiabetes Therapeutics and Research CenterTokushima University, Tokushima 770-8503, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Fujitani
authors.affiliation: Department of Metabolism and EndocrinologyCenter for Molecular DiabetologyCenter for Therapeutic Innovations in DiabetesJapan Science and Technology Agency-Core Research for Evolutionary Science and Technology ProgramJuntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, JapanGraduate School of Medical Science and EngineeringKorea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of KoreaDiabetes Therapeutics and Research CenterTokushima University, Tokushima 770-8503, Japan.
authors.forename: Hail
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Metabolism and EndocrinologyCenter for Molecular DiabetologyCenter for Therapeutic Innovations in DiabetesJapan Science and Technology Agency-Core Research for Evolutionary Science and Technology ProgramJuntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, JapanGraduate School of Medical Science and EngineeringKorea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of KoreaDiabetes Therapeutics and Research CenterTokushima University, Tokushima 770-8503, Japan Department of Metabolism and EndocrinologyCenter for Molecular DiabetologyCenter for Therapeutic Innovations in DiabetesJapan Science and Technology Agency-Core Research for Evolutionary Science and Technology ProgramJuntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, JapanGraduate School of Medical Science and EngineeringKorea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of KoreaDiabetes Therapeutics and Research CenterTokushima University, Tokushima 770-8503, Japan Department of Metabolism and EndocrinologyCenter for Molecular DiabetologyCenter for Therapeutic Innovations in DiabetesJapan Science and Technology Agency-Core Research for Evolutionary Science and Technology ProgramJuntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, JapanGraduate School of Medical Science and EngineeringKorea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of KoreaDiabetes Therapeutics and Research CenterTokushima University, Tokushima 770-8503, Japan.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Watada
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D005091:Exons / Q000235:genetics; D005260:Female; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D053614:Janus Kinase 2 / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000235:genetics; D051379:Mice; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D011247:Pregnancy; D011388:Prolactin / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D050799:STAT5 Transcription Factor / Q000235:genetics / Q000378:metabolism; D012701:Serotonin / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D024363:Transcription Initiation Site / Q000502:physiology; D014158:Transcription, Genetic / Q000235:genetics; D014365:Tryptophan Hydroxylase / Q000235:genetics* / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D050799:STAT5 Transcription Factor; C494093:Stat5a protein, mouse; D015534:Trans-Activators; D012701:Serotonin; D011388:Prolactin; C487801:Tph1 protein, mouse; D014365:Tryptophan Hydroxylase; D019869:Phosphatidylinositol 3-Kinases; C507926:Jak2 protein, mouse; D053614:Janus Kinase 2
keywords: Erk; MIN6 cell; PI3-kinase; Stat; Tph1; islet; pregnancy; prolactin; serotonin; β cell