Abstract: Background: Hypertrophic cardiomyopathy (HCM) is the most common feline heart disease; its pathogenesis is largely unknown. MicroRNAs have been reported to play a role in human HCM pathogenesis. MicroRNA sequencing of feline HCM hearts was carried out, which identified known and novel microRNAs.
Objective: Evaluate novel microRNAs identified in hearts from cats with HCM.
Animals: 5 left ventricles (LV) and 5 left atria (LA) from cats with HCM (group 1), and 7 LV and 5 LA from healthy cats (group 2).
Methods: MicroRNAs from the LV and LA of group 1 and 2 were compared using miRDeep2. Novel microRNA sequences were evaluated to determine homologs (BLAST) and to assess their candidacy (RNAfold).
Results: Comparing the LV with the LA in each group identified 33 differentially expressed novel microRNAs in group 1 and 46 in group 2. 15 were found in both the HCM and healthy LV, indicating chamber specificity. 55 and 44 novel microRNAs were differently expressed comparing the LV and LA respectively from group 1 with group 2. 44 of the LV and 33 of the LA microRNAs were chamber specific. 11 microRNAs (7 down-regulated, 4 up-regulated) were similarly expressed in both the LV and LA, suggesting chamber-independent involvement in HCM. 30 microRNAs were homologs, 29 were orthologs, and for 29 microRNAs no species overlap was identified, indicating the discovery of microRNAs unreported so far.
Conclusions: This study identified HCM and cardiac-chamber specific novel microRNAs. Further investigations into their role in feline HCM pathogenesis is required.
Learning Objectives:
Define novel microRNAs.
Outline myocardial novel miRNAs found in health and feline hypertrophic cardiomyopathy.
Distinguish chamber specific novel miRNAs in the healthy and HCM feline heart.
