title: Bioluminescence imaging of β cells and intrahepatic insulin gene activity under normal and pathological conditions.
abstract: In diabetes research, bioluminescence imaging (BLI) has been applied in studies of β-cell impairment, development, and islet transplantation. To develop a mouse model that enables noninvasive imaging of β cells, we generated a bacterial artificial chromosome (BAC) transgenic mouse in which a mouse 200-kbp genomic fragment comprising the insulin I gene drives luciferase expression (Ins1-luc BAC transgenic mouse). BLI of mice was performed using the IVIS Spectrum system after intraperitoneal injection of luciferin, and the bioluminescence signal from the pancreatic region analyzed. When compared with MIP-Luc-VU mice [FVB/N-Tg(Ins1-luc)VUPwrs/J] expressing luciferase under the control of the 9.2-kbp mouse insulin I promoter (MIP), the bioluminescence emission from Ins1-luc BAC transgenic mice was enhanced approximately 4-fold. Streptozotocin-treated Ins1-luc BAC transgenic mice developed severe diabetes concomitant with a sharp decline in the BLI signal intensity in the pancreas. Conversely, mice fed a high-fat diet for 8 weeks showed an increase in the signal, reflecting a decrease or increase in the β-cell mass. Although the bioluminescence intensity of the islets correlated well with the number of isolated islets in vitro, the intensity obtained from a living mouse in vivo did not necessarily reflect an absolute quantification of the β-cell mass under pathological conditions. On the other hand, adenovirus-mediated gene transduction of β-cell-related transcription factors in Ins1-luc BAC transgenic mice generated luminescence from the hepatic region for more than 1 week. These results demonstrate that BLI in Ins1-luc BAC transgenic mice provides a noninvasive method of imaging islet β cells and extrapancreatic activity of the insulin gene in the liver under normal and pathological conditions.
authors.affiliation: Department of Anatomy and Embryology, Faculty of Medicine, University of Tsukuba, Tennodai, Tsukuba, Ibaraki, Japan.
authors.forename: Tokio
authors.initials: T
authors.lastname: Katsumata
authors.forename: Hisashi
authors.initials: H
authors.lastname: Oishi
authors.forename: Yukari
authors.initials: Y
authors.lastname: Sekiguchi
authors.forename: Haruka
authors.initials: H
authors.lastname: Nagasaki
authors.forename: Dhouha
authors.initials: D
authors.lastname: Daassi
authors.forename: Pei-Han
authors.initials: PH
authors.lastname: Tai
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Ema
authors.forename: Takashi
authors.initials: T
authors.lastname: Kudo
authors.forename: Satoru
authors.initials: S
authors.lastname: Takahashi
mesh_terms: D000818:Animals; D058948:Cell Tracking; D059305:Diet, High-Fat; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D023061:Gene Order; D018390:Gene Targeting; D018014:Gene Transfer Techniques; D007328:Insulin / Q000235:genetics* / Q000378:metabolism*; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008163:Luminescent Measurements / Q000379:methods; D051379:Mice; D008822:Mice, Transgenic; D057054:Molecular Imaging / Q000379:methods; D009928:Organ Specificity / Q000235:genetics; D013311:Streptozocin / Q000494:pharmacology
chemical_list: D007328:Insulin; D013311:Streptozocin; D008156:Luciferases