MicroRNA sequencing from ventricles of Sham and TAC mice treated with antimiR-control and antimiR-34. Mus musculus

Expression of the miR-34 family (miR-34a, -34b, -34c) is elevated in settings of heart disease, and inhibition with antimiR-34a/antimiR-34 has emerged as a promising therapeutic strategy. Under chronic cardiac disease settings, targeting the entire miR-34 family is more effective than targeting miR-34a alone. The identification of transcription factor (TF)-miRNA regulatory networks has added complexity to understanding the therapeutic potential miRNA-based therapies. Here, we sought to determine whether antimiR-34 targets secondary miRNAs via TFs which could contribute to antimiR-34-mediated protection. Using miRNA-Seq we identified differentially regulated miRNAs in hearts from mice with cardiac pathology due to transverse aortic constriction (TAC), and these miRNAs were also regulated by antimiR-34. Two clusters of stress-responsive miRNAs were classified as “pathological” and “cardioprotective”. Using ChIPBase we identified 45 TF binding sites on the promoters of “pathological” and “cardioprotective” miRNAs, and 5 represented direct targets of miR-34, with the capacity to regulate other miRNAs. The expression of two “pathological” miRNAs (let-7e and miR-31) was independently experimentally validated in hearts from antimiR-34 treated TAC mice, and may explain why targeting the entire miR-34 family is more effective than targeting miR-34a alone. AntimiR-34 regulates the expression of other miRNAs and this has significant implications for drug development. Overall design: MicroRNA-seq profiles in ventricles of mice that develop cardiac hypertrophy induced by transverse aortic constriction (TAC) or sham-operated controls and treated with LNA-antimiR-34 or LNA-control. Four groups of samples were analyzed : Sham LNA-control (n=4), Sham LNA-antimiR-34 (n=3), TAC LNA-control (n=3) and TAC LNA-antimiR-34 (n=4)