title: Pharmacological regulation of the insulin receptor signaling pathway mimics insulin action in cells transduced with viral vectors.
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.
authors.affiliation: Telethon Institute of Genetics and Medicine (TIGEM), 80131 Naples, Italy.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Cotugno
authors.forename: Roy
authors.initials: R
authors.lastname: Pollock
authors.forename: Pietro
authors.initials: P
authors.lastname: Formisano
authors.forename: Katja
authors.initials: K
authors.lastname: Linher
authors.forename: Francesco
authors.initials: F
authors.lastname: Beguinot
authors.forename: Alberto
authors.initials: A
authors.lastname: Auricchio
mesh_terms: D015153:Blotting, Western; D002460:Cell Line; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D000229:Dependovirus / Q000235:genetics; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism; D019281:Dimerization; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000378:metabolism; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D006006:Glycogen Synthase / Q000378:metabolism; D006720:Homozygote; D006801:Humans; D047468:Immunoprecipitation; D007328:Insulin / Q000378:metabolism*; D055504:Insulin Receptor Substrate Proteins; D007333:Insulin Resistance; D009154:Mutation; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D011972:Receptor, Insulin / Q000378:metabolism*; D015398:Signal Transduction; D016559:Tacrolimus / Q000031:analogs & derivatives* / Q000494:pharmacology; D013997:Time Factors; D014443:Tyrosine / Q000378:metabolism
chemical_list: C463061:AP20187; C526292:IRS1 protein, human; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; D010750:Phosphoproteins; D014443:Tyrosine; D006006:Glycogen Synthase; D011972:Receptor, Insulin; D016559:Tacrolimus