Brief annotation and scientific rationale:
The aim of the research is to study the molecular, genetic and organismal effects of ionizing radiation with different physical characteristics. The use of ionizing radiation of a wide range of linear energy transfer in radiobiological experiments allows obtaining unique information on the nature of the damage to the DNA structure of cells after irradiation, the mechanisms of the induction of gene and structural mutations in cells with different levels of genome organization, and the action of particle radiation on tumor during radiation therapy. Within the framework of the Theme, fundamental and applied problems of modern radiation biology will be addressed: the formation and repair of cluster DNA damage in normal and tumor cells following exposure to accelerated charged particles; the study of the radiosensitizing effect of the DNA repair modifier AraC in combination with various molecular biological complexes during irradiation of tumor cells and tissues; the study of the induction of gene and structural mutations in normal and tumor cells following exposure to charged particles; investigation of acute and long-term morphological and functional changes in the mammalian central nervous system following exposure to radiation with different physical characteristics.

When organizing radiobiological experiments with charged particle beams, it is extremely important to improve physico-dosimetric complexes, provide precision dosimetry, and conduct computer simulation of radiation-induced effects. In this regard, the urgent tasks are: the need for experimental modeling of the energy and spectral composition of cosmic and other types of ionizing radiation; the search for methods for non-destructive analysis of unique samples; and automated processing of biological experiment data. In the course of the research, it is planned to develop new setups and dosimetry systems for irradiating biological samples; introduce methods for non-destructive analysis of unique samples, develop and test systems for automated computer processing of biological data; formulate new mathematical models and computational approaches for radiobiology, bioinformatics and radiation medicine; and identify mechanisms and pathways of catalytic synthesis of prebiotic compounds under the action of radiation.

Expected results upon completion of the project:
To study clustered DNA DSB formation after exposure to accelerated charged particles of different energies in the nuclei of human skin fibroblasts, tumor cells, and neurons of different parts of the central nervous system of irradiated animals.

To study the repair kinetics of clustered DNA DSB in the post-irradiation period in the nuclei of human skin fibroblasts and radioresistant tumor cells.

To study mechanisms of the radiosensitizing effect of cytosine arabinoside in combination with various molecular biological complexes on normal and tumor cells after exposure to radiation with different LET.

To study quantitatively the survival of normal and tumor cells after radiation exposure in the presence of a combination of DNA repair modifiers.

To continue investigation of point and structural mutation induction in Saccharomyces cerevisiae yeast cells by radiation with different LET.

To study the influence of heterogeneity of cell population in haploid yeast on the radiation-induced mutagenesis; estimate mutagenesis in different phases of cell cycle.

To study the influence of respiratory impairment as the result of mitochondrial DNA damage on the sensitivity to the mutagenic effect of radiation.

To study the mechanism of radioresistance and its effect on radiation-induced mutagenesis in yeast mutants.

To continue the study of radiation-induced mutagenesis and to compare the yield of chromosomal aberrations in Chinese hamster cells at the highest and lowest mutagenesis levels depending on the time of expression and LET of accelerated ions.

To analyse structural disorders in the hprt gene and their projection on disorders in the chromosome machinery of cells.

To finalise the mFISH study of the biological effectiveness of proton beams.

To study the biological effectiveness of low-energy X-rays following in vitro irradiation of human blood lymphocytes using the mFISH method.

To evaluate the contribution of complex chromosome aberrations to the biological effectiveness of densely ionizing radiations following irradiation of human normal and tumour cells in vitro.

To study the induction and kinetics of chromatin break repair by premature chromatin condensation in normal and tumour human cells exposed to sparsely and densely ionizing radiation.

To continue the study of primary and late morphological and functional changes in the central nervous system of rats following exposure to ionizing radiation with different physical characteristics.

To conduct studies of pharmacological protection agents' action under ionizing radiation exposure.

To continue the investigation of the activation of microglial cells in cell culture and inflammatory markers in the brain of mice following exposure to ionizing radiation of different quality.

To investigate the possibility to modulate the activation of microglial cells in irradiated culture and neuroinflammation in the brain of irradiated mice by using inhibitors to the receptors of signalling pathways involved in these processes.

To study in vivo the radiosensitizing effect of cytosine arabinoside in combination with other molecular biological complexes on melanoma tumor growth in mice following the combined exposure to these agents and proton radiation.

To evaluate the influence of the combined action of AraC and other molecular biological complexes on the survival of different normal and tumor cell lines  based on clonogenic survival  criterion upon X-ray and proton irradiation.

To study the kinetics of the formation and elimination of DNA damage in U87 glioblastoma and other radioresistant cell cultures after proton and X-ray exposure in the presence of AraC and other molecular biological complexes.

To study DNA DSB formation in different components of the central nervous system after in vivo irradiation with protons and X-rays in the presence of a combination of radiomodifiers.

Expected results of the project in the current year:
To continue the analysis of the formation and repair of clustered DNA double-strand breaks after exposure to accelerated charged particles and photon radiation in normal and tumor cells (human fibroblasts, U87 glioblastoma cells, and B16 murine melanoma cells) and in neurons of different parts of the central nervous system of animals.

To continue the analysis of the formation and structure of complex clustered DNA damage using immunocytochemical staining of the repair proteins γH2AX, 53BP1, OGG1, and XRCC1 in normal and tumor cells (human fibroblasts, U87 glioblastoma cells, and B16 murine melanoma cells) after exposure to accelerated charged particles and photon radiation.

To continue the selection of modifiers that increase the radiosensitivity of tumor cells in combination with cytosine arabinoside when exposed in vivo and in vitro to ionizing radiations with different physical characteristics.

To continue research on the radiosensitizing effect of cytosine arabinoside in various combinations with repair modifiers on the survival, formation, and elimination of DNA damage in normal and tumor cells.

To analyze chromosomal abnormalities in radiation-induced mutants and their descendants expressed in the region of the minimum HPRT mutagenesis level and in the long term after irradiation of V79 Chinese hamster cells with γ-rays and accelerated boron ions.

To continue studying the induction of structural changes in yeast cells by ionizing radiations with different LET.

To continue research on the effect of heterogeneity of the yeast cell population on sensitivity to the lethal and mutagenic action of UV and ionizing radiations.

To continue studying the effect of mitochondrial DNA damage on radiosensitivity and mutagenesis.

To continue metaphase and mFISH analysis of chromosomal aberrations induced in peripheral blood lymphocytes of Macaca mulatta monkeys by accelerated carbon ions.

Using the premature chromatin condensation method, to evaluate the induction of primary chromatin damage and the kinetics of its repair in human normal and tumor cells after exposure to photons, accelerated protons, and accelerated nitrogen ions.

To study the genetic stability of mouse neural stem cells in culture using the mFISH method, depending on their origin and duration of cultivation.

Using the mFISH method, to study the biological effectiveness of soft X-rays and the spectrum of chromosomal aberrations they induce.

To continue the study of impairments in long-term memory and learning ability of rats in the Morris test and T-maze test after whole-body irradiation.

To investigate long-term morphological changes in the central nervous system and small intestine of rats after whole-body proton irradiation.

To develop a method for assessing changes in the regenerative capacity of intestinal crypts when using radiomodifiers.

To continue studying behavioral reactions, electroencephalography signals, and morphological changes in rats after local X-ray exposure of the brain using the SARRP facility.

At the SARRP facility, to adapt the experimental B16 melanoma model in vivo and optimize the conformal radiation therapy parameters using radiomodifiers.

To assess the effectiveness of radioprotectors using small laboratory animal models.

To study the cytotoxicity, degree of accumulation, and localization in cells of protoporphyrin IX and a complex of protoporphyrin IX and gadolinium using cell lines of human breast carcinoma (Cal-51, MDA-468, and MDA-231) and colorectal cancer (HCT-116) and evaluate their survival when exposed to X-rays.

Bref annotation and scientific rationale:
A wide range of JINR's ionizing radiation sources, especially heavy ion beams of various energies, offer a unique opportunity to solve a number of fundamental problems of radiobiology and astrobiology, as well as practical problems related to space exploration and the development of radiation medicine.

Due to the high complexity and cost of performing biological experiments at accelerator complexes, it is of paramount importance to improve experimental methods, ensure dosimetry and radiation safety, and perform relevant computer simulations. The most pressing issues here are the need for experimental reproduction of the energy and spectral composition of cosmic and other types of ionizing radiation, the search for methods for non-destructive analysis of unique samples and automated processing of biological experiment data, as well as the high complexity and resource intensity of computer simulation of processes in living systems.

This project is aimed at solving a complex of the above problems arising in radiobiological and astrobiological research. In the course of its implementation, it is planned to develop new stations for irradiation and dosimetry systems; introduce methods for non-destructive analysis of unique samples; develop and test systems for automated computer processing of biological data; formulate new mathematical models and computational approaches for radiobiology, bioinformatics, and radiation medicine; and identify mechanisms and pathways of the catalytic synthesis of prebiotic compounds under radiation exposure.

Expected results upon completion of the project:
Provision of dosimetry and irradiation of biological samples at JINR accelerators.

Upgrade and commissioning of the Genome-3 facility.

Development of a multimodal tomography system for small laboratory animals.

Equipping a room for radiobiological experiments using radionuclides.

Creation of a prototype space radiation simulator.

Development and testing of instruments for neutron dosimetry and spectrometry.

Development of an information system for working with experimental data in the form of two-dimensional images, computed tomography data, and video recordings.

Development of protocols for labeling two-dimensional images and video materials, formation of a labeled database.

Testing the implemented analysis algorithms; development and registration of software designed for automated data processing.

Development of mathematical models of the formation and repair of various types of DNA damage and models of the formation of mutations and chromosomal aberrations.

Molecular dynamics modeling of structural and functional disorders in mutant and oxidized forms of proteins.

Development of mathematical models of radiation-induced death of tumor cells and prediction of tumor growth for promising radiation therapy methods.

Theoretical evaluation of radiation-induced disorders of the CNS on the basis of mathematical models of brain neural networks, taking into account damage to synaptic receptors, oxidative stress, and impaired neurogenesis and gliogenesis.

Study of possible pathways of, and conditions for, the formation of prebiotic compounds by irradiation of cosmic matter or terrestrial rocks in combination with the simplest organic molecules.

Search for, and structural analysis of, microfossils and organic compounds in various meteorites by nuclear physics methods.

Expected results of the project in the current year:
To develop a mathematical model of the formation and repair kinetics of clustered DNA damage induced by accelerated heavy charged particles of different energies, taking into account the cell cycle phase, in mammalian normal and tumor cells.

To develop a mathematical model of the dynamics of the tumor cell population after ionizing radiation exposure in the presence of DNA synthesis inhibitors.

To develop mathematical models of oxidative damage to cell membranes and organelles induced by ionizing radiation.

To develop mathematical models of the survival and population dynamics of stem cells in normal and tumor tissues after exposure to ionizing radiations with different physical characteristics.

To develop a mathematical model of chromosomal aberration induction in mammalian and human cells by ionizing radiations with different characteristics.

Using molecular dynamics methods, to study the accumulation in cell structures and the stability of molecules of promising radiomodifiers, contrast agents, and drugs for neutron capture therapy.

To apply computer vision algorithms to biological data processing in histology and behavioral experiments.

To update and put into practice guidelines for organizing and conducting radiobiological experiments using LRB irradiation facilities.

To continue the development of software systems to improve computational methods for determining the physical characteristics of the radiation field and precision dosimetry for LRB radiobiological experiments.

To continue improving X-ray tomography techniques and planning conformal irradiation of small laboratory animals, taking into account minimizing the negative impact on organs at the SARRP facility.

To ensure the operability of the existing Genom-2M facility; to carry out the assembly, installation, and testing of the Genom-3 facility at applied beams of the U400M cyclotron.

To take part in the modeling and study of radiation fields during the operation of applied research stations (ISKRA and SIMBO) in the Measurement Hall of the NICA complex, at the MSC-230 accelerator, and at the IREN facility as part of working groups (the Laboratory of High Energy Physics, Laboratory of Nuclear Problems, Laboratory of Neutron Physics, and Radiation Safety Department).

To continue calculations and creation of a new neutron dosimeter based on helium and boron counters of a wide energy range.

To investigate the processes of fossilization of microorganisms.

To conduct experiments on the synthesis of prebiotic compounds from formamide under irradiation with accelerated charged particles in the presence of the substance of terrestrial minerals and meteorites.

To conduct an experiment on the synthesis of prebiotic compounds in space (participation in the BION program).

Collaboration