Development Of A Transgenic Rat Expressing The Human Chymase Gene To Study Human Cardiovascular Disease

Objectives: To improve the development of therapies better able to suppress intracrine Ang II actions, experimental models with human chymase and angiotensinogen genes are needed. Methods: To create the human chymase rat model, the human chymase 1 gene with Myc-DDK tag was subcloned into a superactive Sleeping Beauty transposon (SB 100X). After Sanger sequencing validation of the inserted human chymase 1 gene, the plasmid, together with the transposase, was injected with the plasmid containing the chymase (CMA1) gene and mRNA of the transposase into the pronucleus of one cell SD embryos and transferred into pseudopregnant SD females. From the first rounds of injections, 17 pups were born with 9 positive transgenic founders (CAG-CMA1 transgene). Five lines were established by backcrossing. Results: Several of the founders had unusual traits including curly and patchy fur, curly tail tips, reduced body weight, and some exhibited a spinning phenotype. Pups from two of the lines after backcrossing (lines B and D) continued to have small body size and trichosis. Transgenic positive CMA1 pups from all five backcrossed lines express hCMA1 via RT PCR. Preliminary data suggests that CMA1 positive transgenic rats have an increase in white blood cell count compared to transgenic negative littermates. Conclusion: This new humanized rat model expressing human CMA1 [SD-Tg (CAG-CMA1)Mcwi] when combined in on-going studies with transgenic rats expressing the human angiotensinogen gene will become a choice model for the development of therapies that are highly effective in blocking angiotensin II tissue hyperactivity.