title: Visualization of glucagon secretion from pancreatic α cells by bioluminescence video microscopy: Identification of secretion sites in the intercellular contact regions.
abstract: We have firstly visualized glucagon secretion using a method of video-rate bioluminescence imaging. The fusion protein of proglucagon and Gaussia luciferase (PGCG-GLase) was used as a reporter to detect glucagon secretion and was efficiently expressed in mouse pancreatic α cells (αTC1.6) using a preferred human codon-optimized gene. In the culture medium of the cells expressing PGCG-GLase, luminescence activity determined with a luminometer was increased with low glucose stimulation and KCl-induced depolarization, as observed for glucagon secretion. From immunochemical analyses, PGCG-GLase stably expressed in clonal αTC1.6 cells was correctly processed and released by secretory granules. Luminescence signals of the secreted PGCG-GLase from the stable cells were visualized by video-rate bioluminescence microscopy. The video images showed an increase in glucagon secretion from clustered cells in response to stimulation by KCl. The secretory events were observed frequently at the intercellular contact regions. Thus, the localization and frequency of glucagon secretion might be regulated by cell-cell adhesion.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan; School of Pharmacy, Aichi Gakuin University, Nagoya 464-8650, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Yokawa
authors.affiliation: School of Dentistry, Aichi Gakuin University, Nagoya 464-8650, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Yokohama Research Center, JNC Corporation, Yokohama 236-8605, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Inouye
authors.affiliation: School of Pharmacy, Aichi Gakuin University, Nagoya 464-8650, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Inoh
authors.affiliation: Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Suzuki
authors.affiliation: School of Dentistry, Aichi Gakuin University, Nagoya 464-8650, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Kanamori
authors.affiliation: School of Pharmacy, Aichi Gakuin University, Nagoya 464-8650, Japan.
authors.forename: Tadahide
authors.initials: T
authors.lastname: Furuno
authors.affiliation: Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan. Electronic address: hirashim@phar.nagoya-cu.ac.jp.
authors.forename: Naohide
authors.initials: N
authors.lastname: Hirashima
mesh_terms: D000818:Animals; D060829:Arthropod Proteins / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D033342:Copepoda / Q000201:enzymology; D005934:Glucagon / Q000378:metabolism*; D050416:Glucagon-Secreting Cells / Q000187:drug effects / Q000378:metabolism*; D005947:Glucose / Q000494:pharmacology; D006801:Humans; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008163:Luminescent Measurements / Q000379:methods*; D051379:Mice; D018613:Microscopy, Confocal; D018715:Microscopy, Video / Q000379:methods*; D011189:Potassium Chloride / Q000494:pharmacology; D052336:Proglucagon / Q000235:genetics / Q000378:metabolism; D022142:Secretory Vesicles / Q000187:drug effects / Q000378:metabolism
chemical_list: D060829:Arthropod Proteins; D052336:Proglucagon; D011189:Potassium Chloride; D005934:Glucagon; D008156:Luciferases; D005947:Glucose
keywords: Bioluminescence imaging; Exocytosis; Gaussia luciferase; Glucagon; Pancreatic α cell; Secretion