title: Multimodality imaging of β-cells in mouse models of type 1 and 2 diabetes.
abstract: OBJECTIVE
  β-Cells that express an imaging reporter have provided powerful tools for studying β-cell development, islet transplantation, and β-cell autoimmunity. To further expedite diabetes research, we generated transgenic C57BL/6 "MIP-TF" mice that have a mouse insulin promoter (MIP) driving the expression of a trifusion (TF) protein of three imaging reporters (luciferase/enhanced green fluorescent protein/HSV1-sr39 thymidine kinase) in their β-cells. This should enable the noninvasive imaging of β-cells by charge-coupled device (CCD) and micro-positron emission tomography (PET), as well as the identification of β-cells at the cellular level by fluorescent microscopy.
  
  
  METHODS
  MIP-TF mouse β-cells were multimodality imaged in models of type 1 and type 2 diabetes.
  
  
  RESULTS
  MIP-TF mouse β-cells were readily identified in pancreatic tissue sections using fluorescent microscopy. We show that MIP-TF β-cells can be noninvasively imaged using microPET. There was a correlation between CCD and microPET signals from the pancreas region of individual mice. After low-dose streptozotocin administration to induce type 1 diabetes, we observed a progressive reduction in bioluminescence from the pancreas region before the appearance of hyperglycemia. Although there have been reports of hyperglycemia inducing proinsulin expression in extrapancreatic tissues, we did not observe bioluminescent signals from extrapancreatic tissues of diabetic MIP-TF mice. Because MIP-TF mouse β-cells express a viral thymidine kinase, ganciclovir treatment induced hyperglycemia, providing a new experimental model of type 1 diabetes. Mice fed a high-fat diet to model early type 2 diabetes displayed a progressive increase in their pancreatic bioluminescent signals, which were positively correlated with area under the curve-intraperitoneal glucose tolerance test (AUC-IPGTT).
  
  
  CONCLUSIONS
  MIP-TF mice provide a new tool for monitoring β-cells from the single cell level to noninvasive assessments of β-cells in models of type 1 diabetes and type 2 diabetes.
authors: Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, California, USA.
authors: Jing
authors: J
authors: Yong
authors: Julia
authors: J
authors: Rasooly
authors: Hoa
authors: H
authors: Dang
authors: Yuxin
authors: Y
authors: Lu
authors: Blake
authors: B
authors: Middleton
authors: Zesong
authors: Z
authors: Zhang
authors: Larry
authors: L
authors: Hon
authors: Mohammad
authors: M
authors: Namavari
authors: David B
authors: DB
authors: Stout
authors: Mark A
authors: MA
authors: Atkinson
authors: Jide
authors: J
authors: Tian
authors: Sanjiv Sam
authors: SS
authors: Gambhir
authors: Daniel L
authors: DL
authors: Kaufman
mesh_terms: D000818:Animals; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism* / Q000473:pathology*; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism* / Q000473:pathology*; D005434:Flow Cytometry; D005951:Glucose Tolerance Test; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D007328:Insulin / Q000235:genetics; D050417:Insulin-Secreting Cells / Q000378:metabolism* / Q000473:pathology*; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D049268:Positron-Emission Tomography; D011401:Promoter Regions, Genetic / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013937:Thymidine Kinase / Q000235:genetics / Q000378:metabolism
chemical_list: D007328:Insulin; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D008156:Luciferases; D013937:Thymidine Kinase