title: Functional Analysis of Novel Candidate Regulators of Insulin Secretion in the MIN6 Mouse Pancreatic β Cell Line.
abstract: Elucidating the regulation of glucose-stimulated insulin secretion (GSIS) in pancreatic β cells is important for understanding and treating diabetes. The pancreatic β cell line, MIN6, retains GSIS but gradually loses it in long-term culture. The MIN6 subclone, MIN6c4, exhibits well-regulated GSIS even after prolonged culture. We previously used DNA microarray analysis to compare gene expression in the parental MIN6 cells and MIN6c4 cells and identified several differentially regulated genes that may be involved in maintaining GSIS. Here we investigated the potential roles of six of these genes in GSIS: Tmem59l (Transmembrane protein 59 like), Scgn (Secretagogin), Gucy2c (Guanylate cyclase 2c), Slc29a4 (Solute carrier family 29, member 4), Cdhr1 (Cadherin-related family member 1), and Celsr2 (Cadherin EGF LAG seven-pass G-type receptor 2). These genes were knocked down in MIN6c4 cells using lentivirus vectors expressing gene-specific short hairpin RNAs (shRNAs), and the effects of the knockdown on insulin expression and secretion were analyzed. Suppression of Tmem59l, Scgn, and Gucy2c expression resulted in significantly decreased glucose- and/or KCl-stimulated insulin secretion from MIN6c4 cells, while the suppression of Slc29a4 expression resulted in increased insulin secretion. Tmem59l overexpression rescued the phenotype of the Tmem59l knockdown MIN6c4 cells, and immunostaining analysis indicated that the TMEM59L protein colocalized with insulin and GM130, a Golgi complex marker, in MIN6 cells. Collectively, our findings suggested that the proteins encoded by Tmem59l, Scgn, Gucy2c, and Slc29a4 play important roles in regulating GSIS. Detailed studies of these proteins and their functions are expected to provide new insights into the molecular mechanisms involved in insulin secretion.
authors.affiliation: Department of Stem Cell Regulation Research, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Kobayashi
authors.affiliation: Department of Nutrition and Food Sciences, Mukogawa Women's University, 6-46 Ikebiraki-cho, Nishinomiya, Hyogo, 663-8558, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Yamato
authors.affiliation: Department of Stem Cell Regulation Research, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Tanabe
authors.affiliation: Department of Stem Cell Regulation Research, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Fumi
authors.initials: F
authors.lastname: Tashiro
authors.affiliation: Department of Stem Cell Regulation Research, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Satsuki
authors.initials: S
authors.lastname: Miyazaki
authors.affiliation: Department of Stem Cell Regulation Research, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Miyazaki
mesh_terms: D000818:Animals; D015153:Blotting, Western; D015820:Cadherins / Q000502:physiology; D002460:Cell Line; D005260:Female; D005455:Fluorescent Antibody Technique; D055785:Gene Knockdown Techniques; D005809:Genes, Regulator / Q000502:physiology; D005947:Glucose / Q000502:physiology; D007328:Insulin / Q000378:metabolism* / Q000502:physiology; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000378:metabolism* / Q000502:physiology; D008565:Membrane Proteins / Q000502:physiology; D026901:Membrane Transport Proteins / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D000074261:Receptors, Enterotoxin; D050705:Receptors, Guanylate Cyclase-Coupled / Q000502:physiology; D018000:Receptors, Peptide / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D064046:Secretagogins / Q000502:physiology
chemical_list: D015820:Cadherins; C498478:Celsr2 protein, mouse; D007328:Insulin; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D018000:Receptors, Peptide; C576557:SCGN protein, mouse; D064046:Secretagogins; C000609623:Tmem59l protein, mouse; C513828:Slc29a4 protein, mouse; C000613655:Gucy2c protein, mouse; D000074261:Receptors, Enterotoxin; D050705:Receptors, Guanylate Cyclase-Coupled; D005947:Glucose