title: Enhanced gene transfer to pancreatic islets using glucagon-like peptide-1.
abstract: OBJECTIVE
  The efficient transfer of genes into intact islets is difficult since islets exist as clusters of differentiated cells with little replication potential. Cell proliferation in response to growth factors is known to be accompanied by loosening of cell-to-cell contacts and increasing paracellular permeability. In this study, we investigated whether gene delivery into intact islet cells was facilitated by modulating β-cell proliferation.
  
  
  METHODS
  Isolated rat islets were pretreated with glucagon-like peptide (GLP)-1 or human growth hormone for 24 hours, or with 300 mg/dL of glucose for 48 hours before transduction with a suboptimal dose of recombinant adenoviral vector expressing green fluorescent protein (GFP) and β-galactosidase (multiplicity of infection of 25). Transduction efficiency was assessed by measuring β-galactosidase activity and GFP expression using enzyme-linked immunosorbent assay, flow cytometry, and fluorescence microscopy. The numbers of 7-aminoactinomycin D-positive dead cells and 5-ethynyl-2-deoxyuridine (EdU)-positive proliferating cells were also monitored using flow cytometry and fluorescence microscopy.
  
  
  RESULTS
  The transduction efficiency of rat islet cells by a suboptimal dose of viral vector was significantly improved by GLP-1 pretreatment, accompanied by enhanced cell viability and cell proliferation. An increased GFP expression in islet cells after GLP-1 pretreatment was observed among the increased numbers of EdU-positive proliferating cells.
  
  
  CONCLUSIONS
  Pretreatment of rat islets with GLP-1 enhanced the transduction efficiency of an adenoviral vector, reducing viral dose burden while improving islet cell viability. From a therapeutic standpoint, genetic modification of pancreatic islets combined with GLP-1 pretreatment may be a promising option for ex vivo gene therapy prior to islet transplantation.
authors.affiliation: Department of Internal Medicine, Hallym University College of Medicine, Chuncheon, Korea.
authors.forename: B W
authors.initials: BW
authors.lastname: Lee
authors.forename: M-H
authors.initials: MH
authors.lastname: Kim
authors.forename: H Y
authors.initials: HY
authors.lastname: Chae
authors.forename: H J
authors.initials: HJ
authors.lastname: Hwang
authors.forename: D
authors.initials: D
authors.lastname: Kang
authors.forename: S H
authors.initials: SH
authors.lastname: Ihm
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D005822:Genetic Vectors; D052216:Glucagon-Like Peptide 1 / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D019382:Human Growth Hormone / Q000494:pharmacology; D007515:Islets of Langerhans / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008856:Microscopy, Fluorescence; D051381:Rats; D017207:Rats, Sprague-Dawley; D046509:Tissue Culture Techniques; D014161:Transduction, Genetic; D014162:Transfection; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D019382:Human Growth Hormone; D049452:Green Fluorescent Proteins; D052216:Glucagon-Like Peptide 1; D001616:beta-Galactosidase; D005947:Glucose