Single \u03b1-particle irradiation permits real-time visualization of RNF8 accumulation at DNA damaged sites

Giovanna Muggiolu,Philippe Barberet,Gérard Claverie,Christine Mer-Calfati,Samuel Saada,Marina Simon,Hervé Seznec,Guillaume Devès,Guillaume Berthet,Michal Pomorski

doi:10.1038/srep41764

Abstract

As well as being a significant source of environmental radiation exposure, α-particles are increasingly considered for use in targeted radiation therapy. A better understanding of α-particle induced damage at the DNA scale can be achieved by following their tracks in real-time in targeted living cells. Focused α-particle microbeams can facilitate this but, due to their low energy (up to a few MeV) and limited range, α-particles detection, delivery, and follow-up observations of radiation-induced damage remain difficult. In this study, we developed a thin Boron-doped Nano-Crystalline Diamond membrane that allows reliable single α-particles detection and single cell irradiation with negligible beam scattering. The radiation-induced responses of single 3 MeV α-particles delivered with focused microbeam are visualized in situ over thirty minutes after irradiation by the accumulation of the GFP-tagged RNF8 protein at DNA damaged sites.

Highlights

Every day humans are exposed to ionizing radiation from natural, industrial and medical sources
Membrane was measured using the experimental set-up depicted on Fig. 1a. It provides a simultaneous measurement of the electrons emitted from the Boron-doped Nano-Crystalline Diamond film (BNCD) surface and of the energy of the particles transmitted through the membrane
We report here the development and validation of an experimental approach that permits, for the first time, the observation of early cellular responses at single α-particle induced DNA damages

Summary

Introduction

Every day humans are exposed to ionizing radiation from natural, industrial and medical sources. Understanding cellular responses to complex DNA damages induced by α-particles is of particular importance and requires specific tools that allow the selective irradiation of single cells and follow-up observations of induced damage via dedicated biological markers (DNA damage signalling, DNA repair protein,..) This can be achieved by exposing living cells to radioactive sources alongside immuno-detection[8] or fluorescence live cell imaging[9]. Modern end-stations, equipped with fluorescence time-lapse imaging, provide the opportunity to visualize and quantify in real-time the early radiation-induced cellular response Using these techniques, studies of DNA damage and repair kinetics[22,23,24], DNA double strand breaks diffusion characteristics[25], and calcium alteration due to heavy-ions[26] have been www.nature.com/scientificreports/. All the detectors mentioned previously are usually a few micrometres thick and cannot be used to detect relatively low energy ions, such as MeV Helium ions delivered by conventional electrostatic accelerators

Methods

Results

Conclusion