ADENOVIRUS-MEDIATED TRANSFER OF A MODIFIED HUMAN PROINSULIN GENE REVERSES HYPERGLYCEMIA IN DIABETIC MICE

The human proinsulin cDNA was introduced into a replication-defective adenovirus and was found to confer proinsulin expression to a hepatocy te (H4-II-E) cell line upon infection. A second virus was constructed in which the dibasic prohormone convertase recognition sequence was mu tated to a tetrabasic furin cleavage site. Cells infected with this vi rus synthesized both proinsulin and mature insulin. Gel filtration chr omatography, competition of insulin binding, and activation of the ins ulin receptor kinase activity demonstrated that this mature insulin wa s functionally identical to that of authentic processed insulin. Injec tion of these viral constructs into the external jugular vein of mice resulted in insulin gene expression in the liver. Expression from the mutated proinsulin virus dramatically improved the glycemic state of d iabetic mice. However, the effects of the viral infection were transie nt, being maximal at similar to 5-7 days and returning to steady-state levels by 14-21 days. These data demonstrate that somatic cell insuli n gene delivery by the use of recombinant adenovirus can be used to tr ansiently reverse the diabetic state in mice.