Pharmacological regulation of the insulin receptor signaling pathway mimics insulin action in cells transduced with viral vectors

Hum Gene Ther. 2004 Nov;15(11):1101-8. doi: 10.1089/hum.2004.15.1101.

Abstract

Diabetes mellitus derives from either insulin deficiency (type I) or resistance (type II). Homozygous mutations in the insulin receptor (IR) gene cause the rare leprechaunism and Rabson-Mendenhall syndromes, severe forms of hyperinsulinemic insulin resistance for which no therapy is currently available. Systems have been developed that allow protein-protein interactions to be brought under the control of small-molecule dimerizer drugs. As a potential tool to rescue glucose homeostasis at will in both insulin and insulin receptor deficiencies, we developed a recombinant chimeric insulin receptor (LFv2IRE) that can be homodimerized and activated by the small-molecule dimerizer AP20187. In HepG2 cells transduced with adeno-associated viral (AAV) vectors encoding LFv2IRE, AP20187 induces LFv2IRE homodimerization and transphosphorylation minutes after drug administration, resulting in the phosphorylation of a canonical substrate of the insulin receptor tyrosine kinase, IRS-1. AP20187 activation of LFv2IRE is dependent on the dose of drug and the amount of chimeric receptor expressed in AAV-transduced cells. Finally, AP20187-dependent activation of LFv2IRE results in insulin-like effects, such as induction of glycogen synthase activity and cellular proliferation. In vivo LFv2IRE transduction of insulin target tissues followed by AP20187 dosing may represent a therapeutic strategy to be tested in animal models of insulin resistance due to insulin receptor deficiency or of type I diabetes. This system may also represent a useful tool to dissect in vivo the independent contribution of insulin target tissues to hormone action.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • Cell Line
  • Cell Line, Tumor
  • Cell Proliferation
  • Dependovirus / genetics
  • Diabetes Mellitus, Type 1 / metabolism
  • Dimerization
  • Dose-Response Relationship, Drug
  • Fibroblasts / metabolism
  • Gene Transfer Techniques
  • Genetic Vectors*
  • Glycogen Synthase / metabolism
  • Homozygote
  • Humans
  • Immunoprecipitation
  • Insulin / metabolism*
  • Insulin Receptor Substrate Proteins
  • Insulin Resistance
  • Mutation
  • Phosphoproteins / metabolism
  • Phosphorylation
  • Protein Structure, Tertiary
  • Receptor, Insulin / metabolism*
  • Signal Transduction*
  • Tacrolimus / analogs & derivatives*
  • Tacrolimus / pharmacology
  • Time Factors
  • Tyrosine / metabolism

Substances

  • AP20187
  • IRS1 protein, human
  • Insulin
  • Insulin Receptor Substrate Proteins
  • Phosphoproteins
  • Tyrosine
  • Glycogen Synthase
  • Receptor, Insulin
  • Tacrolimus