Whole genome cardiac gene expression profiling of transgenic mice with myocardium-specific expression of RKIP (PEBP1), kinase-inactive GRK2-K220R (ADRBK1-K220R), SCD1, and UCP1

The raf kinase inhibitor protein, RKIP, is up-regulated on cadiac biopsy specimens of heart failure patients. To investigate the in vivo role of an increased cardiac content of RKIP, we generated transgenic mice with myocardium-specific expression of RKIP (PEBP1; phosphatidylethanolamine binding protein 1) under control of the alpha-MHC promoter in B6 (C57BL/6J) background. Because RKIP is a dual-specific GRK2 and Raf kinase inhibitor, RKIP-transgenic mice were compared to transgenic mice with myocardium-specific expression of the GRK2 inhibitor, GRK2-K220R, which is a kinase-inactive GRK2 (ADRBK1) mutant with dominant-negative function. In frame of our studies, we found that RKIP-transgenic mice developed signs of heart failure and cardiotoxic lipid load at an age of 8 months. In contrast, transgenic expression of GRK2-K220R improved cardiac function and protected against chronic pressure overload-induced symptoms of heart failure. To identify genes related to cardiotoxic lipid load, we further determined the cardiac gene expression profile of Tg-SCD1 mice with mypcardium-specific expression of SCD1 (stearoyl-CoA desaturase-1) and Tg-UCP1 mice with heart-specific expression of UCP1 (uncoupling protein 1). Whole genome microarray gene expression profiling was performed of hearts from aged, 8-month-old Tg-RKIP mice, Tg-GRK2-K220R mice, Tg-SCD1 mice, and Tg-UCP1 mice. All transgenic mice had B6 background, and the control group consisted of age-matched non-transgenic B6 mice. Two biological replicates were made of each group, and total cardiac RNA of three mice was pooled for one gene chip.