miRNA-34a reduces neointima formation through inhibiting smooth muscle cell proliferation and migration

J Mol Cell Cardiol. 2015 Dec;89(Pt A):75-86. doi: 10.1016/j.yjmcc.2015.10.017. Epub 2015 Oct 19.

Abstract

Aims: We have recently reported that microRNA-34a (miR-34a) regulates vascular smooth muscle cell (VSMC) differentiation from stem cells in vitro and in vivo. However, little is known about the functional involvements of miR-34a in VSMC functions and vessel injury-induced neointima formation. In the current study, we aimed to establish the causal role of miR-34a and its target genes in VSMC proliferation, migration and neointima lesion formation.

Methods and results: Various pathological stimuli regulate miR-34a expression in VSMCs through a transcriptional mechanism, and the P53 binding site is required for miR-34a gene regulation by these stimuli. miR-34a over-expression in serum-starved VSMCs significantly inhibited VSMC proliferation and migration, while knockdown of miR-34a dramatically promoted VSMC proliferation and migration, respectively. Notch homolog 1 (Notch1), a well-reported regulator in VSMC functions and arterial remodeling, was predicted as one of the top targets of miR-34a by using several computational miRNA target prediction tools, and was negatively regulated by miR-34a in VSMCs. Luciferase assay showed miR-34a substantially repressed wild type Notch1-3'-UTR-luciferase activity in VSMCs, but not mutant Notch1-3'-UTR-luciferease reporter, confirming the Notch1 is the functional target of miR-34a in VSMCs. Data from co-transfection experiments also revealed that miR-34a inhibited VSMC proliferation and migration through modulating Notch gene expression levels. Importantly, the expression level of miR-34a was significantly down-regulated in injured arteries, and miR-34a perivascular over-expression significantly reduced Notch1 expression levels, decreased VSMC proliferation, and inhibited neointima formation in wire-injured femoral arteries.

Conclusion: Our data have demonstrated that miR-34a is an important regulator in VSMC functions and neointima hyperplasia, suggesting its potential therapeutic application for vascular diseases.

Keywords: Cell migration; Cell proliferation; MiRNA-34a; MicroRNAs; Neointima; Notch1; Post-angioplasty restenosis; Vascular smooth muscle cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis
  • Base Sequence
  • Cell Movement* / genetics
  • Cell Proliferation
  • Femoral Artery / injuries
  • Femoral Artery / pathology
  • Gene Expression Regulation
  • Mice, Inbred C57BL
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • Molecular Sequence Data
  • Muscle, Smooth, Vascular / pathology
  • Myocytes, Smooth Muscle / pathology*
  • Neointima / genetics*
  • Neointima / pathology*
  • Phenotype
  • Receptors, Notch / metabolism
  • Transcription, Genetic
  • Tumor Suppressor Protein p53 / metabolism

Substances

  • MIRN34a microRNA, mouse
  • MicroRNAs
  • Receptors, Notch
  • Tumor Suppressor Protein p53