Adenovirus-mediated gene delivery to hypothalamic magnocellular neurons inmice

Vasopressin is synthesized by magnocellular neurons in supraoptic (SON) and paraventricular (PVN) hypothalamic nuclei and released by their axon termi nals in the neurohypophysis (NI-I). With its actions as an antidiuretic hor mone and vasoactive agent, vasopressin plays a pivotal role in the control of body fluids and cardiovascular homeostasis, Because of its well-defined neurobiology and functional importance, the SON/PVN-NH system is ideal to e stablish methods for gene transfer of genetic material into specific pathwa ys in the mouse central nervous system. In these studies, we compared the e fficiency of transferring the gene lacZ, encoding for beta-galactosidase (b eta-gal), versus a gene encoding for green fluorescent protein by using rep lication-deficient adenovirus (Ad) vectors in adult mice. Transfection with viral concentrations up to 2 X 10(7) plaque-forming units per coverslip of NH, PVN, and SON in dissociated, cultured cells caused efficient transfect ion without cytotoxicity. However, over an extended period of time, higher levels (50% to 75% of the cells) of beta-gal expression were detected in co mparison with green fluorescent protein (5% to 50% of the cells). With the use of a stereotaxic approach, the pituitary glands of mice were injected w ith Ad (4 x 10(6) plaque-forming units). In material from these animals, we were able to visualize the expression of the beta-gal gene in the NH and i n magnocellular neurons of both the PVN and SON. The results of these exper iments indicate that Ad-Rous sarcoma virus promoter-beta-gal is taken up by nerve terminals at the injection site (NI-I) and retrogradely transported to the soma of the neurons projecting to the NH. We conclude that the appli cation of these experimental approaches will provide powerful tools for phy siological studies and potential approaches to deliver therapeutic genes to treat diseases.