Abstract 11614: Neonatal Mouse Heart Transcriptome Maturation: What Factors Dictate Chamber Specificity?
Purpose: Distinct transcriptomes in the left ventricle (LV) versus the right ventricle (RV) dictate chamber specific pattern of postnatal heart maturation and may be significantly altered in response to perinatal stress leading to pathology, even mortality. However, transcriptome analysis has not been performed in perinatal stages among different cardiac chambers, and the role of alternative RNA splicing in heart maturation is unexplored. We aimed to achieve comprehensive profiling of LV vs. RV transcriptomes during perinatal maturation by using RNA-seq.
METHODS: Deep RNA-seq was performed on male neonatal mouse LV and RV at 3 time points of circulatory transition: P0, P3 and P7. Reads were mapped to the mouse Ensemble transcript sequence Release 64 (Bowtie), and then to mouse Genome (BLAT). Differentially expressed (DE) genes were defined as those with changes ≥ 2-fold between a pair of samples at a false discovery rate ≤ 5% for genes expressed at 3 RPKM in ≥ 1 sample. Genome-Wide difference in inclusion of individual exons was performed using MATS. Expression levels of genes and isoforms were validated using qRT-PCR
RESULTS: Principal component analysis suggested two sources of variation: The tissue effect and the stage effect. Altogether, 2116 genes DE genes and 1162 alternative splicing (AS) events were identified. Skipping exon accounted for 44% of AS events. Distinct genome-wide DE gene profiles and dynamic AS patterns of LV vs. RV during maturation were identified. Gene Ontology analysis revealed enrichment of cell cycle regulators, transcription factors, lipid metabolism and candidate splicing regulators. Interestingly, cell division processes and negative regulators of Wnt- pathway were overexpressed in RV compared to LV, while Wnt activity was elevated in LV and a novel RV enriched AS event in Wnt 11 was identified.
CONCLUSION: Differential expressed genes and AS events revealed potential novel molecular basis for chamber specificity in neonatal heart, including cell proliferation, bioenergetic regulation and Wnt signaling. Further characterization and experimental validation of neonatal heart transcriptome and putative splicing regulators of LV vs. RV maturation will likely lead to novel targets for chamber-specific therapies.
- © 2013 by American Heart Association, Inc.