Heart Failure Associated Changes in RNA Splicing of Sarcomere Genes
Background—Alternative mRNA splicing is an important mechanism for regulation of gene expression. Altered mRNA splicing occurs in association with several types of cancer, and a small number of disease-associated changes in splicing have been reported in heart disease. However, genome-wide approaches have not been used to study splicing changes in heart disease. We hypothesized that mRNA splicing is different in diseased hearts compared to control hearts.
Methods and Results—We used the Affymetrix exon array to globally evaluate mRNA splicing in LV myocardial RNA from control (n=15) and ischemic cardiomyopathy (ICM) patients. We observed a broad and significant decrease in RNA splicing efficiency in heart failure, which affected some introns to a greater extent than others. The profile of mRNA splicing separately clustered ICM and control samples, suggesting distinct changes in RNA splicing between groups. RTPCR validated 9 previously unreported alternative splicing events. Furthermore, we demonstrated that splicing of four key sarcomere genes, cardiac troponin T (TNNT2), cardiac troponin I (TNNI3), myosin heavy chain 7 (MYH7), and filamin C gamma (FLNC), was significantly altered in ICM, as well as in dilated cardiomyopathy and aortic stenosis (AS). In AS samples, these differences preceded the onset of heart failure. Remarkably, the ratio of minor to major splice variants of TNNT2, MYH7, and FLNC classified independent test samples as control or disease with greater than 98% accuracy.
Conclusions—Our data indicate that RNA splicing is broadly altered in human heart disease, and that patterns of aberrant RNA splicing accurately assign samples to control or disease classes.
- Received August 26, 2009.
- Accepted January 6, 2010.
- Copyright © 2010, American Heart Association, Inc. All rights reserved. Unauthorized use prohibited