Abstract 211: Myocardial Hypertrophy and Circulating RNAs
While increased left ventricular mass (LVM) is strongly associated with incident heart failure (HF), events during transition from increased LVM to HF remain unclear. Extracellular non-coding RNAs (ex-RNAs) have been implicated in cardiac hypertrophy, though whether these ex-RNAs reflect important pathways in HF in humans is underexplored. In >2,000 individuals with concomitant M-mode echocardiography and ex-RNA measurements in the Framingham Heart Study, we found that lower circulating concentrations of three ex-RNAs—miR-20a-5p, miR-106b-5p, miR-17-5p—were associated with (1) greater LVM (+ one other pre-clinical phenotype, e.g., left atrial dimension or LVEDV) and (2) greater incident HF risk over a median follow-up 7.7 years ( Fig. A ). These 3 miRNAs were members of a tight cluster, regulating 883 mRNAs in common, associated with “hypertension” (OMIM) and biological process relevant to HF, including TGF-β signaling. We observed an increase in myocardial expression of these miRNAs during different phases of hypertrophy/HF development ( Fig. C, D ). Using gain and loss of function in vitro , our preliminary results suggest up-regulation of cardiomyocyte miR-106b expression abrogates expression of pathologic hypertrophy markers (ANP and BNP) during phenylephrine treatment, consistent with in silico results suggesting broad connections between miR-106b targets and natriuretic peptide signaling ( Fig. B, E-F ). These results provide translational evidence that circulating miRNAs associated with hypertrophy in patients may be protective in the transition from hypertrophy to HF at the molecular level.