Abstract 1474: Usefulness of Exon Array Analysis for Elucidation of Pathogenesis of Heart Failure - Alterations of Splicing Patterns in Murine Failing Hearts
Alternative splicing plays important roles in the pathogenesis of several diseases. However, the role of alternative splicing in the pathogenesis of heart failure remains unclear. The advent of exon array technique enables us to analyze not only the expression level in each gene, but also the expression level in each exon of the gene. In this study, we used exon expression arrays
to develop the splicing pattern profiling in heart failure and
to identify splicing variants responsible for heart failure.
C57/Bl6 mice underwent transverse aortic constriction for 8 weeks, increasing diastolic dimension, and lowering ejection fraction. We constructed exon expression profiling of failing hearts using Mouse Exon 1.0 ST Array. Among 161,159 probes consisting of 10,766 genes on Exon Array, expression levels of 3677 probes (2.28%) of 756 genes changed over 2-fold in failing hearts. We calculated a splicing index of these genes using AssistArray software to examine whether these genes were spliced or not. Among these 756 genes, we revealed 253 genes whose splicing index changed more than twice. These 253 genes were classified into 8 splicing patterns; cassette exon type (18.2%), alternative splice site type (28.0%), alternative promoter type (12.6%), and so on. Next, we investigated gene expression levels of these 253 genes. The gene expression level was altered in 140 genes (Group A; Cd44 and Fnl1), whereas the gene expression level of 113 genes (Group B; Igf1, Fgfr1, and Camk2a) was not changed. Because these 113 genes were not revealed by the conventional 3′ array, these genes might be novel targets for the elucidation of the pathogenesis of heart failure. We also found 112 genes (Group C; Nppa and Hbegf) whose gene expression was only changed. Finally, we checked the characteristics of each group using Ingenuity Pathway Analysis. We found many genes associated with fibrosis (Col2a1 and Tgfβ1) in Group B and genes related with metabolism (Gpx3 and Maob) in Group C. These results imply that splicing regulation and gene expression regulation are different roles in the pathogenesis of heart failure. The analysis of alternative splicing is important to elucidate the pathogenesis of heart failure. Exon Array is a powerful tool for assessing the novel targets for heart failure.