Multiomics approach to identify novel biomarkers for dilated cardiomyopathy: Proteome and transcriptome analyses of 4C30 dilated cardiomyopathy mouse model.

Dilated cardiomyopathy (DCM) is an intractable disease, without any radical treatment option other than cardiac transplantation. Additionally, biomarkers to determine progressive staging are not yet available. Irrespective of the diversity of causative gene mutations, the phenotype of DCM is rather common. Therefore, it is plausible to determine DCM staging in terms of variations in protein and mRNA levels. In this study, we performed proteome and transcriptome analysis of the left ventricle of 4C30 DCM model mice showing mild and severe phenotypes at 12 and 24 weeks (wk) after birth, respectively. Proteomic analyses results showed 109 proteins that increased and 133 others that decreased among 1874 detected proteins. We selected biomarker candidates by confirming consistent alterations in protein levels at 12 and 24 wk, and mRNA levels at 12 wk, and narrowed these down based on the requirement that they should be detectable in blood. Finally, we selected six biomarker candidates based on sustained or augmented alteration at 24 wk and confirmed their definite alterations in the left ventricle by quantitative polymerase chain reaction, western blot analysis, and multiple reaction monitoring (MRM). To assess the validity of this strategy, we measured plasma concentrations of the six candidates by MRM method and identified two proteins (FTL1 and GRP78) that demonstrated significant elevation in the 4C30 mice plasma. Taken together, a multiomics strategy comparing tissue expression levels of proteins and mRNAs between diseased and control groups, with appropriate confirmation, is a promising approach for the discovery of new biomarkers. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 491-502, 2016.