Magnetic bead-based proteome profiling using MALDI-TOF spectrometry in cardiac tissue from transgenic mice

Development of a transgenic animal model always is followed by extensive characterization steps. Here, we intended to test and optimize a fast screening method to get general findings about the differential protein composition in the heart of wild type (WT) and transgenic (TG) mice. Therefore, we developed a protocol for magnetic bead-based separation (MB) combined with Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDITOF MS) for protein profiling in plasma and cardiac tissue from TG and WT mice. We studied tissues from mice with cardiac specific overexpression of the catalytic subunit of PP2A, a model system for cardiac hypertrophy. EDTA-plasma or an extract of homogenized cardiac tissue (or skeletal muscle as control) were fractionated by hydrophobic interaction (MB-HIC C8) or weak cation exchange (MB-WCX) chromatography. MALDI-TOF MS spectra were generated in the mass range of m/z 1000-80000 using different matrices. The number of mass signals in the cardiac tissue extract was critically dependent on the use of the homogenization buffer, the residual blood contamination, and the surface modification of the magnetic beads. We noted different profiles in cardiac homogenates from WT compared to TG. As a control, the profile in skeletal muscle was not different between WT and TG. The results indicate that proteome profiling using MB-based sample preparation combined with MALDI-TOF MS is suitable for the proteome profiling in cardiac tissue of transgenic mice.