Characterization of MIRCOM, IRSN’s new ion microbeam dedicated to targeted irradiation of living biological samples

Vianna, François; Gonon, Géraldine; Lalanne, Kévin; Adam‐Guillermin, Christelle; Bottollier-Depois, J.-F.; Daudin, L.; Dugué, Delphine; Moretto, Philippe; Petit, M.; Sérani, Laurent; Such, J.M.; Gressier, V.

doi:10.1016/j.nimb.2022.01.007

Cited by 7 publications

(11 citation statements)

References 59 publications

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“…All the cells targeted with the α-particle microbeam present rapid phosphorylation of H2AX after irradiation. This result confirms the high precision of targeting with the MIRCOM microbeam line [ 21 ]. In addition, even though we drew a pattern of 9 dots spaced of 1 μm with the MIRCOM microbeam, the targeted cells carried γH2AX staining in a continuous line, this reflected its well-known spreading on chromatin adjacent to DNA breaks [ 16 , 17 ].…”

Section: Discussionsupporting

confidence: 81%

“…We performed the irradiation of samples by using the microbeam of the MIRCOM (“Microfaisceau d’Ions pour la Radiobiologie aux échelles des Cellules et Organismes Multicellulaires”—ion microbeam for radiation biology at the cellular and multicellular scales) facility [ 21 ], operated by the Institut de Radioprotection et de Sûreté Nucléaire (IRSN) in Cadarache, France.…”

Section: Methodsmentioning

confidence: 99%

“…Downstream of the accelerator is the microbeam line itself. For more details, the whole beamline and the working principle of MIRCOM were detailed by Vianna et al [ 21 ]. Briefly, after collimation and focusing with four magnetic quadrupoles in a “Russian quadruplet” configuration, the microbeam is extracted in air through a 150 nm thick Si 3 N 4 extraction window (Silson Ltd., Southampton, UK) and goes through a 250 μm-thick residual layer of air before reaching the cell dish placed in a specific holder.…”

Section: Methodsmentioning

confidence: 99%

“…We irradiated cells with a mean number of ions, controlled by the definition of an opening time of the microbeam on each target, as described previously [ 21 ]. To monitor the beam and thus define this opening time, we used a PIPS detector (PD50-12-100AM, Mirion Technologies (Canberra) S.A.S., Montigny-Le-Bretonneux, France), located on the microscope objective wheel.…”

Section: Methodsmentioning

confidence: 99%

“…For this, we used mouse NIH-3T3 cells, a mammalian cellular model that is widely used for the study of DNA repair and the surrounding chromatin architecture dynamics [ 18 , 19 , 20 ]. We generated DNA damage in these cells with α-particle irradiation delivered by the MIRCOM microbeam facility (IRSN, Cadarache, France), which is dedicated to radiobiology experiments and which thanks to its micrometer precision targeting allows the exclusive irradiation of specific areas within cell nuclei [ 21 ]. Following irradiation with α-particles, we evaluated the recruitment kinetics of the KU70/80 heterodimer (KU), a DSB sensor in NHEJ and RAD51, the recombinase involved in the formation of the nucleoprotein filament that drives HR-mediated DSB repair.…”

Section: Introductionmentioning

confidence: 99%

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Differential Recruitment of DNA Repair Proteins KU70/80 and RAD51 upon Microbeam Irradiation with α-Particles

Bobyk

Vianna

Martinez

et al. 2022

Biology

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In addition to representing a significant part of the natural background radiation exposure, α-particles are thought to be a powerful tool for targeted radiotherapy treatments. Understanding the molecular mechanisms of recognition, signaling, and repair of α-particle-induced DNA damage is not only important in assessing the risk associated with human exposure, but can also potentially help in identifying ways of improving the efficacy of radiation treatment. α-particles (He2+ ions), as well as other types of ionizing radiation, and can cause a wide variety of DNA lesions, including DNA double-strand breaks (DSBs). In mammalian cells, DNA DSBs can be repaired by two major pathways: non-homologous end-joining (NHEJ) and homologous recombination (HR). Here, we investigated their dynamics in mouse NIH-3T3 cells through the recruitment of key proteins, such as the KU heterodimer for NHEJ and RAD51 for HR upon localized α-particle irradiation. To deliver α-particles, we used the MIRCOM microbeam, which allows targeting of subnuclear structures with submicron accuracy. Using mouse NIH-3T3 cells, we found that the KU heterodimer is recruited much earlier at DNA damage sites marked by H2AX phosphorylation than RAD51. We also observed that the difference in the response of the KU complex and RAD51 is not only in terms of time, but also in function of the chromatin nature. The use of a microbeam such as MIRCOM, represents a powerful tool to study more precisely the cellular response to ionizing irradiation in a spatiotemporal fashion at the molecular level.

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Section: Discussionsupporting

confidence: 81%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%