Frontiers in Cardiovascular Medicine (Mar 2020)

Cardiomyocyte Specific Deletion of ADAR1 Causes Severe Cardiac Dysfunction and Increased Lethality

  • Hamid el Azzouzi,
  • Hamid el Azzouzi,
  • Andreia P. Vilaça,
  • Dries A. M. Feyen,
  • Willemijn M. Gommans,
  • Roel A. de Weger,
  • Pieter A. F. Doevendans,
  • Pieter A. F. Doevendans,
  • Pieter A. F. Doevendans,
  • Joost P. G. Sluijter,
  • Joost P. G. Sluijter,
  • Joost P. G. Sluijter

DOI
https://doi.org/10.3389/fcvm.2020.00030
Journal volume & issue
Vol. 7

Abstract

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Background: Adenosine deaminase acting on RNA 1 (ADAR1) is a double-stranded RNA-editing enzyme that is involved in several functions including the deamination of adenosine to inosine, RNA interference (RNAi) mechanisms and microRNA (miRNA) processing, rendering ADAR1 essential for life.Methods and Results: To investigate whether maintenance of ADAR1 expression is required for normal myocardial homeostasis, we bypassed the early embryonic lethality of ADAR1-null mice through the use of a tamoxifen-inducible Cre recombinase under the control of the cardiac-specific α-myosin heavy chain promoter (αMHC). Targeted ADAR1 deletion in adult mice caused a significant increase in lethality accompanied by severe ventricular remodeling and quick and spontaneous cardiac dysfunction, induction of stress markers and overall reduced expression of miRNAs. Administration of a selective inhibitor of the unfolded protein response (UPR) stress significantly blunted the deleterious effects and improved cardiac function thereby prolonging animal survival. In vitro restoring miR-199a-5p levels in cardiomyocytes lacking ADAR1 diminished UPR activation and concomitant apoptosis.Conclusions: Our findings demonstrate an essential role for ADAR1 in cardiomyocyte survival and maintenance of cardiac function through a mechanism that integrates ADAR1 dependent miRNA processing and the suppression of UPR stress.

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