Potential usefulness of D2R reporter gene imaging by IBF as gene therapy monitoring for cerebellar neurodegenerative diseases

Abstract

We investigated a gene expression imaging method to examine the level of therapeutic gene expression in the cerebellum. Using a human immunodeficiency virus derived lentivial vector, we expressed the dopamine D2 receptor (D2R) as a reporter protein to mouse cerebellar Purkinje cells. Biodistribution and ex vivo autoradiography studies were performed by giving [125I]5-iodo-7-N-[(1-ethyl-2-pyrrolidinyl)methyl]carboxamide-2,3- dihydrobenzofuran ([125I]IBF) (1.85 MBq), as a radioactive D 2R ligand, to model mice expressing the D2R with an HA tag (HA-D2R) in the cerebellum. In this study, [125I]IBF was bound to the D2R expressed in the cerebellum of the model mice selectively. Immunostaining was performed to confirm the HA-D2R expression in the cerebellum of the model mice. A significant correlation (r=0.900, P<0.001) between areas that expressed HA-D2R by immunostaining and areas in which [125I]IBF accumulated by the ex vivo autoradiograms was found. These results indicated that radioiodinated IBF is useful as a reporter probe to detect D2R reporter gene expression, which can be used for monitoring therapeutic gene expression in the cerebellum. © 2009 ISCBFM All rights reserved.