Biomedicines (Jun 2021)

miR-208b Reduces the Expression of Kcnj5 in a Cardiomyocyte Cell Line

  • Julia Hupfeld,
  • Maximilian Ernst,
  • Maria Knyrim,
  • Stephanie Binas,
  • Udo Kloeckner,
  • Sindy Rabe,
  • Katja Quarch,
  • Danny Misiak,
  • Matthew Fuszard,
  • Claudia Grossmann,
  • Michael Gekle,
  • Barbara Schreier

DOI
https://doi.org/10.3390/biomedicines9070719
Journal volume & issue
Vol. 9, no. 7
p. 719

Abstract

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MicroRNAs (miRs) contribute to different aspects of cardiovascular pathology, among them cardiac hypertrophy and atrial fibrillation. Cardiac miR expression was analyzed in a mouse model with structural and electrical remodeling. Next-generation sequencing revealed that miR-208b-3p was ~25-fold upregulated. Therefore, the aim of our study was to evaluate the impact of miR-208b on cardiac protein expression. First, an undirected approach comparing whole RNA sequencing data to miR-walk 2.0 miR-208b 3′-UTR targets revealed 58 potential targets of miR-208b being regulated. We were able to show that miR-208b mimics bind to the 3′ untranslated region (UTR) of voltage-gated calcium channel subunit alpha1 C and Kcnj5, two predicted targets of miR-208b. Additionally, we demonstrated that miR-208b mimics reduce GIRK1/4 channel-dependent thallium ion flux in HL-1 cells. In a second undirected approach we performed mass spectrometry to identify the potential targets of miR-208b. We identified 40 potential targets by comparison to miR-walk 2.0 3′-UTR, 5′-UTR and CDS targets. Among those targets, Rock2 and Ran were upregulated in Western blots of HL-1 cells by miR-208b mimics. In summary, miR-208b targets the mRNAs of proteins involved in the generation of cardiac excitation and propagation, as well as of proteins involved in RNA translocation (Ran) and cardiac hypertrophic response (Rock2).

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