Targeting brain stem centers of cardiovascular control using adenoviral vectors: impact of promoters on transgene expression.

Adenoviral vectors (AVV) are widely used as tools for exploring gene function in studies of the central autonomic control, but the cellular specificity of the promoters commonly used in these vectors has not been studied. We evaluated AVV with four "wide-spectrum" promoters, human cytomegalovirus promoter (HCMV), synapsin-1 promoter (Syn1), tubulin-alpha1 promoter (Talpha1), and neuron-specific enolase (NSE) for their ability to express enhanced green fluorescent protein (EGFP) within the dorsal vagal complex and the adjacent brain stem. They were compared with the PRSx8 promoter, specifically designed to target catecholaminergic neurons. AdHCMVEGFP, AdSyn1EGFP-WHE (woodchuck hepatitis enhancer element), AdTalpha1EGFP, and AdNSEEGFP were unable to drive expression of EGFP in dopamine beta-hydroxylase-immunoreactive neurons of the A2 cell group, although the adjacent dorsal vagal motonucleus and especially hypoglossal motoneurons did express high levels of EGFP. AdPRSx8EGFP efficiently drove EGFP expression in the A2 cell group but also in choline acetyltransferase-positive vagal motoneurons. However, catecholaminergic neurons could be selectively and efficiently transduced via a retrograde route by injecting the vector into their target areas. Thus AVV with "wide-spectrum" promoters have strikingly different activity in the diverse cellular populations within brain stem cardiovascular control centers. The PRSx8 promoter is a valuable tool for the study of the role of catecholaminergic neurons.