Local Cre-Mediated Gene Recombination in Vascular Smooth Muscle Cells in Mice

Abstract

Here we describe a means to conditionally modify genes at a predefined and localized region of the vasculature using a perivascular drug delivery device (PDD). A 4-hydroxytamoxifen (4-OHT)-eluting PDD was applied around the carotid or femoral artery of a mouse strain carrying both the tamoxifen-inducible and smooth muscle cell (SMC)-specific Cre-recombinase (SM-Cre-ER^T2) transgene and a stop-floxed β-galactosidase gene in the Rosa26 locus: the SM-CreER^T2(ki)/rosa26 mouse. A dose and time curve of 0–10% (w/w) 4-OHT and 0–14 days application of the PDD in SM-CreER^T2(ki)/rosa26 mice showed optimal gene recombination at 1% (w/w) 4-OHT loading at 7 days post application (carotid artery 2.4±1.8%; femoral artery 4.0±3.8% of SMCs). The unique 4-OHT-eluting PDD allowed us to achieve SMC-specific recombination in the same order of magnitude as compared to systemic tamoxifen administration. In addition, recombination was completely confined to the PDD-treated vessel wall segment. Thus, local application of a 4-OHT-eluting PDD results in vascular SMC-specific Cre-mediated recombination in SM-CreER^T2(ki)/rosa26 mice without affecting additional SMCs.