Abstract 107: RNA Seq Transcriptome Analysis Reveals Genes and Pathways Involved in the Cardiac Protection of VCP Against Pressure Overload

Aims: We previously showed that the valosin containing protein (VCP), a member of ATPases associated protein, protects the heart against pressure overload induced cardiac hypertrophy and dysfunction in transgenic (TG) mice. The mechanisms remain unknown. We hypothesize that VCP regulated alteration in transcriptome contributes to its cardio-protection by targeting cardiac cell growth and survival. Methods and results: Cardiac-specific VCPTG mice and their litter-matched wild type (WT) mice were subjected to transverse aortic constriction (TAC) for 2 and 5 weeks and compared to the sham mice. By using echocardiography and hemodynamic analysis, cardiac hypertrophy and dysfunction were confirmed in 2 weeks- and 5 weeks- TAC models respectively in WT but not in VCPTG mice. Total RNA was extracted from left ventricular tissues and gene expression was determined by RNA-Seq transcriptome analysis. Upon 2 weeks TAC, 690 differentially expressed genes were identified between VCPTG and WT (Fold Change ≥ 1.5, P value ≤ 0.05). Among these genes, VCPTG TAC mice, compared to WT TAC mice, showed significant activation of the genes linked to transcriptional factors, Protein Kinase CGMP-Dependent Type I ( Prkg1 ) and Kruppel Like factor 15 ( Klf15 ), the known repressors of cardiac hypertrophy under stress. On the contrary, there is significant increase in cardiac hypertrophy associated genes in WT TAC mice, such as myosin light chain 7 ( Myl7 ), periostin ( Postn ) and tropomyosin beta chain ( Tpm2) , and in fetal gene natriuretic peptide A ( Nppa) , but these alterations were not observed in VCPTG TAC mice, which may contribute to repression of cardiac hypertrophy in VCPTG mice. In addition, pro-apoptosis genes, such as platelet factor 4 ( Pf4), Pleckstrin homology like domain A1 ( Phlda1 ) and Radical S-Adenosyl Methionine Domain Containing 2 ( Rsad2 ), are significantly downregulated continually in 2 weeks through 5 weeks TAC in VCPTG mice, but not in WT TAC, which may contribute to the protection of cell survival in VCPTG mice. Conclusion: Significant difference of gene regulation exists between VCPTG and WT in the heart under the pressure overload which may be the mechanism of VCP mediated cardiac protection.