Positive radionuclide imaging of miRNA expression using RILES and the human sodium iodide symporter as reporter gene is feasible and supports a protective role of miRNA-23a in response to muscular atrophy

PLoS One. 2017 May 11;12(5):e0177492. doi: 10.1371/journal.pone.0177492. eCollection 2017.


MicroRNAs (miRNAs) are key players in many biological processes and are considered as an emerging class of pharmacology drugs for diagnosis and therapy. However to fully exploit the therapeutic potential of miRNAs, it is becoming crucial to monitor their expression pattern using medical imaging modalities. Recently, we developed a method called RILES, for RNAi-Inducible Luciferase Expression System that relies on an engineered regulatable expression system to switch-ON the expression of the luciferase gene when a miRNA of interest is expressed in cells. Here we investigated whether replacing the luciferase reporter gene with the human sodium iodide symporter (hNIS) reporter gene will be also suited to monitor the expression of miRNAs in a clinical setting context. We provide evidence that radionuclide imaging of miRNA expression using hNIS is feasible although it is not as robust as when the luciferase reporter gene is used. However, under appropriate conditions, we monitored the expression of several miRNAs in cells, in the liver and in the tibialis anterior muscle of mice undergoing muscular atrophy. We demonstrated that radiotracer accumulation in transfected cells correlated with the induction of hNIS and with the expression of miRNAs detected by real time PCR. We established the kinetic of miRNA-23a expression in mice and demonstrated that this miRNA follows a biphasic expression pattern characterized by a loss of expression at a late time point of muscular atrophy. At autopsy, we found an opposite expression pattern between miRNA-23a and one of the main transcriptional target of this miRNA, APAF-1, and as downstream target, Caspase 9. Our results report the first positive monitoring of endogenously expressed miRNAs in a nuclear medicine imaging context and support the development of additional work to establish the potential therapeutic value of miRNA-23 to prevent the damaging effects of muscular atrophy.

MeSH terms

  • Animals
  • Apoptotic Protease-Activating Factor 1 / metabolism
  • Blotting, Western
  • Caspase 9 / metabolism
  • Cell Membrane / metabolism
  • Feasibility Studies
  • Female
  • Gene Expression Regulation
  • Genes, Reporter*
  • HeLa Cells
  • Humans
  • Liver / metabolism
  • Luciferases / metabolism*
  • Luminescent Measurements
  • Mice, Inbred BALB C
  • MicroRNAs / genetics*
  • MicroRNAs / metabolism
  • Muscle, Skeletal / metabolism
  • Muscle, Skeletal / pathology
  • Muscular Atrophy / diagnostic imaging*
  • Muscular Atrophy / genetics*
  • Muscular Atrophy / pathology
  • RNA Interference*
  • Radionuclide Imaging / methods*
  • Symporters / metabolism*
  • Tomography, Emission-Computed, Single-Photon
  • Tomography, X-Ray Computed
  • Transfection


  • Apaf1 protein, mouse
  • Apoptotic Protease-Activating Factor 1
  • MicroRNAs
  • Mirn23b microRNA, mouse
  • Symporters
  • sodium-iodide symporter
  • Luciferases
  • Caspase 9

Grants and funding

This work was supported by the French National Cancer Institute (INCA, N°2014-168, MARENGO project). Viorel Simion is supported by a postdoctoral fellowship from the Marengo INCA funding.