title: Prevention of Reg I-induced β-cell apoptosis by IL-6/dexamethasone through activation of HGF gene regulation.
abstract: Reg (regenerating gene) product, Reg protein, is induced in pancreatic β-cells and acts as autocrine/paracrine growth factor for regeneration via the cell surface Reg receptor. However, high concentrations of Reg I protein induced β-cell apoptosis. In the present study, we found that hepatocyte growth factor (HGF) attenuated the β-cell apoptosis induced by the high concentrations of Reg I protein and that the combined stimulation of interleukin-6 (IL-6) and dexamethasone (Dx) induced the accumulation of HGF mRNA as well as Reg I mRNA in β-cells. The accumulation of the HGF mRNA was caused by the activation of the HGF promoter. Deletion analysis revealed that the region of -96 to -92 of the HGF gene was responsible for the promoter activation by IL-6+Dx. The promoters contain a consensus transcription factor binding sequence for signal transducer and activator of transcription (STAT). Site-directed mutations of STAT-binding motif in the region markedly attenuated the HGF promoter activity. Chromatin immunoprecipitation assay showed that STAT3 is located at the active HGF promoter in response to IL-6+Dx stimulation. These results strongly suggest that the combined stimulation of IL-6 and glucocorticoids induces the activation of both Reg and HGF genes and that the anti-apoptotic effects of HGF against the Reg I-induced apoptosis may help β-cell regeneration by Reg I protein.
authors: Department of Advanced Biological Sciences for Regeneration (Kotobiken Medical Laboratories), Tohoku University Graduate School of Medicine, Sendai 980-8575, Miyagi, Japan; Department of Surgery, Tohoku University Graduate School of Medicine, Sendai 980-8575, Miyagi, Japan.
authors: Kei
authors: K
authors: Nakagawa
authors: Department of Advanced Biological Sciences for Regeneration (Kotobiken Medical Laboratories), Tohoku University Graduate School of Medicine, Sendai 980-8575, Miyagi, Japan; Department of Biochemistry, Nara Medical University, Kashihara 634-8521, Nara, Japan. Electronic address: shintksw@naramed-u.ac.jp.
authors: Shin
authors: S
authors: Takasawa
authors: Department of Advanced Biological Sciences for Regeneration (Kotobiken Medical Laboratories), Tohoku University Graduate School of Medicine, Sendai 980-8575, Miyagi, Japan; Department of Medical Biochemistry, Iwate Medical University, School of Pharmacy, Yahaba 920-0293, Iwate, Japan.
authors: Koji
authors: K
authors: Nata
authors: Department of Biochemistry, Nara Medical University, Kashihara 634-8521, Nara, Japan.
authors: Akiyo
authors: A
authors: Yamauchi
authors: Department of Biochemistry, Nara Medical University, Kashihara 634-8521, Nara, Japan.
authors: Asako
authors: A
authors: Itaya-Hironaka
authors: Department of Biochemistry, Nara Medical University, Kashihara 634-8521, Nara, Japan.
authors: Hiroyo
authors: H
authors: Ota
authors: Department of Biochemistry, Nara Medical University, Kashihara 634-8521, Nara, Japan.
authors: Kiyomi
authors: K
authors: Yoshimoto
authors: Department of Biochemistry, Nara Medical University, Kashihara 634-8521, Nara, Japan.
authors: Sumiyo
authors: S
authors: Sakuramoto-Tsuchida
authors: Department of Biochemistry, Nara Medical University, Kashihara 634-8521, Nara, Japan.
authors: Tomoko
authors: T
authors: Miyaoka
authors: Department of Biochemistry, Nara Medical University, Kashihara 634-8521, Nara, Japan.
authors: Maiko
authors: M
authors: Takeda
authors: Department of Surgery, Tohoku University Graduate School of Medicine, Sendai 980-8575, Miyagi, Japan.
authors: Michiaki
authors: M
authors: Unno
authors: Department of Advanced Biological Sciences for Regeneration (Kotobiken Medical Laboratories), Tohoku University Graduate School of Medicine, Sendai 980-8575, Miyagi, Japan; Tohoku University, Sendai 980-8577, Miyagi, Japan.
authors: Hiroshi
authors: H
authors: Okamoto
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001483:Base Sequence; D019610:Cytoprotection / Q000187:drug effects; D003907:Dexamethasone / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D017228:Hepatocyte Growth Factor / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D050417:Insulin-Secreting Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D015850:Interleukin-6 / Q000494:pharmacology*; D051847:Lithostathine / Q000378:metabolism* / Q000494:pharmacology; D008297:Male; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D050796:STAT3 Transcription Factor / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D015850:Interleukin-6; D051847:Lithostathine; D012333:RNA, Messenger; C497616:Reg1a protein, rat; D050796:STAT3 Transcription Factor; D017228:Hepatocyte Growth Factor; D003907:Dexamethasone
keywords: 3-aminobenzamide; 3AB; 4[-3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate; ChIP; Chromatin immunoprecipitation; Dx; FCS; GAPDH; GATA; Glucocorticoids; HGF; HGF gene; HSF-2; IL-6; NA; NOD mouse; Nrf-2; PARP; Pancreatic β cell; RT-PCR; Reg; Reg protein; STAT; Transcriptional control; WST-1; dexamethasone; fetal calf serum; glyceraldehyde-3-phosphate dehydrogenase; heart shock factor 2; hepatocyte growth factor; interleukin-6; nicotinamide; non-obese diabetic mouse; nuclear respiratory factor 2; poly(ADP-ribose) polymerase; regenerating gene; reverse transcription polymerase chain reaction; signal transducer and activator of transcription; transcription factor