Engineered beta-cells secreting dipeptidyl peptidase IV-resistant glucagon-like peptide-1 show enhanced glucose-responsiveness
2005 (English)In: Life Sciences, ISSN 0024-3205, E-ISSN 1879-0631, Vol. 76, no 11, 1239-1248 p.Article in journal (Refereed) Published
Type 2 diabetes is a polygenic disorder characterized by increased insulin resistance, and impaired insulin secretion leading to abnormalities of glucose and lipid metabolism. Reduced responsiveness of the beta-cells to glucose is a critical feature of this syndrome. Glucagon-like peptide 1, a product of the pro-glucagon gene makes beta-cells competent and has many other anti-diabetic properties. We speculated whether GLP-1-based gene therapy could be an approach for treatment of type 2 diabetes. We started with a clone of rat insulinoma cells (S4 cells), which showed reduced responsiveness to glucose in terms of insulin secretion. We transfected these cells with a plasmid encoding a mutated form of GLP-1 (GLP-1-Gly8), which is resistant to the degrading enzyme dipeptidyl-peptidase IV. Activity of secreted GLP-1-Gly8 was assayed using Chinese hamster lung fibroblasts (CHL) cells that expressed cloned GLP-1 receptor and that were transfected with CRE-Luc. Stable cell lines (Glipsulin cells) obtained by this means produced and stored immunoreactive GLP-1-Gly8. In addition to insulin, the Glipsulin cells secreted the GLP-1-Gly8. The secreted GLP-1-Gly8 was active as evidenced by the ability of the conditioned media to elevate cAMP levels in CHL cells expressing GLP-1 receptors. Glipsulin cells responded to glucose with a 6.8 fold increase in insulin secretion compared to a 2.2 fold increase in the control cells. Our results demonstrate that prolonged exposure to GLP-1-Gly8 secreted by increases glucose-responsiveness of these cells. We speculate that engineering GLP-1-Gly8 secretion by beta-cells is a potential gene therapeutic strategy to treat diabetes.
Place, publisher, year, edition, pages
2005. Vol. 76, no 11, 1239-1248 p.
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:uu:diva-132140DOI: 10.1016/j.lfs.2004.08.021PubMedID: 15642594OAI: oai:DiVA.org:uu-132140DiVA: diva2:357054