Tissue-specific targeting of lentiviral vectors using neuronal or astrocytic promoters and various pseudotyping

Tissue targeting is of major interest to study the contribution of cellular subpopulations in neurodegenerative diseases and to develop safe and efficient protocols for gene therapy. In this study, we evaluated various promoters and VSV or Mokola pseudotyping. Tetracycline-regulated lentiviral vectors expressing the green fluorescent protein (GFP) reporter gene were produced. Neuronal promoters of prion (PrP), synapsin I (SYN), neuron-specific enolase (NSE), glutamic acid decarboxylase of 67 kDa (GAD), dopaminergic receptor 1 (D1R), glutamate receptor 1 (GluR1), preprotachykinin 1 (TAC1), enkephalin (ENK), homeobox dlx5/6 (dlx5/6-CMVmin) were compared with the ubiquitous phosphoglycerate kinase (PGK) promoter. Astrocytic promoters of glial fibrillary acidic protein (GFA2, GFA-ABC1D) and glutamine synthetase (GS) were studied in parallel to the excitatory amino acid transporter 1 (EAAT1) promoter. Stereotaxic injection of the vectors was done into the striatum and hippocampus, two structures implicated in Huntington's and Alzheimer's diseases, respectively. Tissue-specificity and transgene expression levels were analyzed by measuring the total GFP intensity and the number of infected cells. Preliminary results indicate that GAD, dlx5/6-CMVmin, PrP and PGK promoters lead to high transduction efficiency and strong neuronal expression whereas SYN, NSE, D1R, GluR1, TAC1 and ENK lead to a weaker expression. Evaluation of astrocytic promoters is underway and data will be presented.