Stretch-sensitive down-regulation of the miR-144/451 cluster in vascular smooth muscle and its role in AMP-activated protein kinase signaling

PLoS One. 2013 May 21;8(5):e65135. doi: 10.1371/journal.pone.0065135. Print 2013.

Abstract

Vascular smooth muscle cells are constantly exposed to mechanical force by the blood pressure, which is thought to regulate smooth muscle growth, differentiation and contractile function. We have previously shown that the expression of microRNAs (miRNAs), small non-coding RNAs, is essential for regulation of smooth muscle phenotype including stretch-dependent contractile differentiation. In this study, we have investigated the effect of mechanical stretch on miRNA expression and the role of stretch-sensitive miRNAs for intracellular signaling in smooth muscle. MiRNA array analysis, comparing miRNA levels in stretched versus non-stretched portal veins, revealed a dramatic decrease in the miR-144/451 cluster level. Because this miRNA cluster is predicted to target AMPK pathway components, we next examined activation of this pathway. Diminished miR-144/451 expression was inversely correlated with increased phosphorylation of AMPKα at Thr172 in stretched portal vein. Similar to the effect of stretch, contractile differentiation could be induced in non-stretched portal veins by the AMPK activator, AICAR. Transfection with miR-144/451 mimics reduced the protein expression level of mediators in the AMPK pathway including MO25α, AMPK and ACC. This effect also decreased AICAR-induced activation of the AMPK signaling pathway. In conclusion, our results suggest that stretch-induced activation of AMPK in vascular smooth muscle is in part regulated by reduced levels of miR-144/451 and that this effect may play a role in promoting contractile differentiation of smooth muscle cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AMP-Activated Protein Kinases / metabolism*
  • Aminoimidazole Carboxamide / analogs & derivatives
  • Aminoimidazole Carboxamide / pharmacology
  • Animals
  • Aorta / drug effects
  • Aorta / metabolism
  • Base Sequence
  • Carotid Arteries / drug effects
  • Carotid Arteries / metabolism
  • Down-Regulation / drug effects
  • Down-Regulation / genetics*
  • Enzyme Activation / drug effects
  • Male
  • Mice
  • Mice, Inbred C57BL
  • MicroRNAs / genetics*
  • MicroRNAs / metabolism
  • Molecular Sequence Data
  • Muscle Contraction / drug effects
  • Muscle, Smooth, Vascular / cytology
  • Muscle, Smooth, Vascular / drug effects
  • Muscle, Smooth, Vascular / enzymology*
  • Myocytes, Smooth Muscle / drug effects
  • Myocytes, Smooth Muscle / enzymology
  • Phosphorylation / drug effects
  • Portal Vein / drug effects
  • Portal Vein / metabolism
  • Pressure
  • Ribonucleotides / pharmacology
  • Signal Transduction* / drug effects
  • Signal Transduction* / genetics
  • Stress, Mechanical*
  • Transfection

Substances

  • MIRN144 microRNA, mouse
  • MicroRNAs
  • Mirn451 microRNA, mouse
  • Ribonucleotides
  • Aminoimidazole Carboxamide
  • AMP-Activated Protein Kinases
  • AICA ribonucleotide

Grants and funding

This work has been supported by The Swedish Research Council, The Heart and Lung Foundation, The Greta and Johan Kock's Foundation, The Crafoord Foundation; The Royal Physiographic Society; The Åke Wiberg Foundation; The Tore Nilson Foundation; The Magnus Bergvall Foundation, The Lars Hierta Memorial Foundation, The Jeansson Foundation. KT is supported by the Marie Curie Initial Training Network Small Artery Remodelling (SmArt) from the European Union. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.