Proteomic analysis of Rac1 transgenic mice displaying dilated cardiomyopathy reveals an increase in creatine kinase M-chain protein abundance.

Here, we demonstrate the application of the proteomic approach to the study of a transgenic mouse model of heart failure and provide an example of a disease-associated protein alteration that can be observed using this approach. Specifically, we applied the proteomic approach to the analysis of a mouse model of dilated cardiomyopathy in which the small GTPase, Rac1, was constitutively expressed specifically in the myocardium. We utilized the methods of two-dimensional gel electrophoresis (2-DE) for protein separation, silver-staining for protein visualization and mass spectrometry (MALDI-TOF and MS/MS) for protein spot identification. Computer-generated composite images were created which represent a normalized average of four 2-DE gel images derived from analysis of either Rac1 transgenic (n = 4) or non-transgenic (n = 4) mice. Analysis of composite images derived from NTG and Rac1 experimental groups revealed numerous statistically significant differences in mean protein spot intensities. Here, we report a statistically significant increase, of approximately 1.6-fold, in the mean protein spot intensity for creatine kinase M-chain in the composite image of Rac1 transgenic mice compared to control. This protein alteration may be consistent with an end-stage heart failure phenotype in which maximal myocardial reserve is employed to sustain survival.