Canine adenovirus (CAV-2) vectors induce an innate immune response and the modulation of cell cycle genes in dopaminergic differentiated human midbrain neuronal precursors

CAV-2 vectors circumvent the ubiquitous human anti-human Adenovirus (hAd) memory immune response, are capable of long term neuron-specific expression (>1year in rat brains), do not induce the maturation of dendritic cells and have been proposed for the treatment of neurodegenerative diseases. In the prospect of clinical applications to brain diseases in humans, we investigated the toxicogenomic profile of helper-dependent (HD) CAV-2 vectors in human midbrain precursors differentiated into dopaminergic neurons. We transduced the cultures with HD CAV-2 and, for comparison, with third generation SIN lentiviral vectors (LV) and HD hAd. We evaluated gene modulation by Affymetrix gene chip at 2h and 5 days post transduction. Our analyses of the chip-contained 47,000 transcripts showed that, at the moi of 1000 genomes per cell, HD CAV-2 exhibited a specific modulation profile. It induced genes belonging to the cell cycle, DNA recombination and repair pathways, including p53, RAD51, BIRC5, FANCD2 and MAD2L1. It also up regulated genes involved in the immune response and in inflammation, including TL3 and 4, HAS3 and CD44, and genes involved in neuron projection morphogenesis. HD hAd was less efficient in transduction than HD CAV-2 and its effect on the trascriptome was milder. However, at 2h, it did have an impact on neuron remodeling and trafficking genes. LV transduced very efficiently, had a strong effect on the trascriptome, which overlapped with that of HD CAV-2 for TLR activation, and diverged in specific aspects of the immune and DNA repair gene groups. Single gene and pathway modulation data emerged from our analysis constitute useful information for toxicity prediction, vector comparison and evolution and virus-host interaction studies.