Altering Central Nervous System Physiology with a Defective Herpes Simplex Virus Vector Expressing the Glucose Transporter Gene

Because of their postmitotic nature, neurons are difficult subjects for gene transfer. To circumvent this, we have used a defective herpes simplex virus vector to overexpress the rat brain glucose transporter (GT) gene under the control of the human cytomegalovirus ie1 promoter. This vector, designated vIE1GT, was propagated using a herpes simplex virus type 1 temperature-sensitive mutant, ts756, GT expressed from vIE1GT was readily immunoprecipitated from membrane fractions of vIE1GT-infected Vero cells. By using indirect double immunofluorescence techniques, vIE1GT was shown to be capable of enhancing GT expression in cultured hippocampal neurons and glia. Glucose transport in such vIE1GT-infected cultures was increased ≈ 2-fold relative to controls. The efficacy of this system in vivo was then tested by microinjection of vIE1GT into adult rat hippocampus. When examined 2 days later, GT expression from vIE1GT was demonstrated in hippocampal neurons by in situ hybridization; a small but significant increase in glucose transport was detected in tissue immediately surrounding the injection site by 2-deoxy[14C]glucose uptake and autoradiography. Such injections did not cause marked cytopathology. Thus, this approach can be used to alter central nervous system physiology in vitro and in vivo.