Abstract 39: Cyp4a1 Transgenic Rats Generated Using Sleeping Beauty Transposon System Restores the Impaired Myogenic Responses in the Afferent Arteriole of Dahl S Rats

We have reported that the production of 20-HETE is reduced in the renal vasculature of Dahl S rats and that myogenic and TGF responses of afferent arteries (Af-Art) are impaired in Dahl S rats. In this study we generated CYP4A1 transgenic rats in the Dahl S inbred strain background utilizing the enhanced Sleeping Beauty (SB100X) transposon system to determine if upregulation of 20-HETE production can restore vascular reactivity and oppose the development of renal injury. Fertilized eggs collected from female Dahl S rats were microinjected with a transposon vector harboring the rat CYP4A1 cDNA under the control of the ubiquitous CAG promoter along with SB100X transposase mRNA to produce transgenic founders. Heterozygous founders were backcrossed to Dahl S rats, transgene insertion sites were identified by Ligation Mediated PCR and sequencing, and the progeny were brother-sister mated to derive homozygous transgenic lines. The expression of CYP4A protein was significantly elevated and the production of 20-HETE was 3-fold higher in the renal outer medullary tissue of CYP4A1 transgenic (n=17) compared to Dahl S rats (n=17). 20-HETE production was 10-fold higher in renal microvessels of CYP4A1 transgenic animals than Dahl S rats. (0.2±0.3, n=22 versus 1.9±0.1 pmol/mg/min, n=14). The luminal diameter of the Af-Art decreased significantly from 15.9 ± 0.6 to 14.1 ± 0.5 μm in CYP4A1 transgenic rats (n=5) when the perfusion pressure was increased from 60 to 120 mmHg, whereas it remained unaltered in Dahl S rats (from 19.4 ± 2.3 to 20.6 ± 5.6 μm, n=22). These studies further support the view that a deficiency in the formation of 20-HETE in the renal microcirculation contributes to the marked susceptibility of Dahl S rats to develop of hypertension and diabetic induced renal injury, and the new CYP4A1 transposon transgenic rat model may be useful for determining the mechanisms involved.