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 with control hearts.


RESULTS
We used the Affymetrix Exon array to globally evaluate mRNA splicing in left ventricular myocardial RNA from controls (n=15) and patients with ischemic cardiomyopathy (n=15). We observed a broad and significant decrease in mRNA splicing efficiency in heart failure, which affected some introns to a greater extent than others. The profile of mRNA splicing separately clustered ischemic cardiomyopathy and control samples, suggesting distinct changes in mRNA splicing between groups. Reverse transcription-polymerase chain reaction validated 9 previously unreported alternative splicing events. Furthermore, we demonstrated that splicing of 4 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 ischemic cardiomyopathy and in dilated cardiomyopathy and aortic stenosis. In aortic stenosis 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 >98% accuracy.


CONCLUSIONS
Our data indicate that mRNA splicing is broadly altered in human heart disease and that patterns of aberrant RNA splicing accurately assign samples to control or disease classes.
Kong
Sek Won
SW
Department of Cardiology, Children's Hospital Boston, Mass, USA.
Hu
Yong Wu
YW
Ho
Joshua W K
JW
Ikeda
Sadakatsu
S
Polster
Sean
S
John
Ranjit
R
Hall
Jennifer L
JL
Bisping
Egbert
E
Pieske
Burkert
B
dos Remedios
Cristobal G
CG
Pu
William T
WT
D001024:Aortic Valve Stenosis / Q000235:genetics; D002311:Cardiomyopathy, Dilated / Q000235:genetics; D019295:Computational Biology; D003285:Contractile Proteins / Q000235:genetics; D005091:Exons; D064448:Filamins; D006333:Heart Failure / Q000235:genetics*; D006352:Heart Ventricles / Q000378:metabolism; D006801:Humans; D008840:Microfilament Proteins / Q000235:genetics*; D017202:Myocardial Ischemia / Q000235:genetics; D018995:Myosin Heavy Chains / Q000235:genetics; D012326:RNA Splicing; D012518:Sarcomeres / Q000235:genetics*; D019210:Troponin I / Q000235:genetics; D020107:Troponin T / Q000235:genetics
D003285:Contractile Proteins; C578661:FLNC protein, human; D064448:Filamins; D008840:Microfilament Proteins; C545568:TNNT2 protein, human; D019210:Troponin I; D020107:Troponin T; D018995:Myosin Heavy Chains