Aim: to compare the repair process of DNA double-strand breaks in mammalian cells after acute versus prolonged exposure to X-ray irradiation with different dose rates. Material and methods. Studies were performed on primary human fibroblasts isolated from skin biopsies of healthy volunteers (women, 29 and 30 years). Cells were irradiated using an X-ray machine RUB RUST-M1 (JSC "Ruselectronics", Moscow, Russia) at 37°C temperature with a dose rate of 400 mGy/min (200 kV, 2*2.4 mA, a filter of 1.5mm AI) or 4 mGy/min (50 kV, 2*0.4 mA, a filter of 1.5 mm AI). Immuno-cytochemical protein staining was utilized for yH2AX and Rad51 foci analysis. Results. Phosphorylated histone H2AX (yH2AX) and the key protein of homologous recombination Rad51 foci formation and disappearance kinetics were investigated simultaneously in primary human dermal fibroblasts after acute and prolonged exposure to X-ray radiation at a same dose. It was shown that the relative yield of yH2AX foci per dose reduces with decrease in dose rate, while the relative yield of Rad51 foci conversely increases. Conclusion. Our findings suggest the fundamental differences in the ratio of non-homologous end joining and homologous recombination DNA repair in acute versus prolonged irradiated cells.
Ozerov I.V., Eremin P.S., Osipov A.N., Eremin I.I., Tsvetkova A.D., Guseva S.S., Ivanova K.Yu., Gavrilenko 0.I., Pustovalova M.V., Smetanina N.M., Grekhova A.K., Lazareva N.L., Pullin A.A., Maksimova О.A., Gordeev A.V., Bushmanov A.Yu., Kotenko K.V. Characteristics of changes in the number of yH2AX and Rad51 protein foci in human skin fibroblasts after prolonged exposure to low-dose rate X-ray radiation // Saratov Journal of Medical Scientific Research, Vol. 10, Issue 4, 2014, pp. 739-743

The influence of mechanical stress in fibroblasts membrane integrins on the content of free intracellular Ca2+ at native and depolymerized actin microfilaments of cytoskeleton
Grytsenko M. A., Kot K. V., Kot Yu. G., Altukhova L. V., Bulankina N. I., Persky Ye. E. The influence of mechanical stress in fibroblasts membrane integrins on the content of free intracellular Ca2+ at native and depolymerized actin microfilaments of cytoskeleton //Cell Technology Week 2013. Conference Proceedings. – Kyiv, May 14-17 2013. – Kyiv. – P. 41-42.

The impact of integrins oscillation on intracellular calcium in conditions of native actin microfilaments network and under depolymerization was studied on the model of α(2)β(1)-integrins forced cyclic fluctuations with the use of integrin-specific magnetic microparticles, that were exposed to magnetic field after being cell-attached. It proved that α(2)β(1)-integrins are involved in the response of fibroblasts to mechanical deformation, activating depot-dependent calcium efflux in cytoplasm. Cytoskeletal actin microfilaments are also involved in the response via these receptors, which integrity is essential for normal functioning of the depot-dependent mechanism of Ca2+ efflux in cytoplasm of deformable fibroblasts.
Kot E.V., Kot Yu.G., Grytsenko M.A., Altukhova L.V., Persky Ye.E. Relation between integrins forced oscillation, degree of actin cytoskeleton polymerization and content of free Ca2+ of fibroblasts // European Researcher. – 2013. – Vol. 40. – № 2 – 1. – Р. 226 – 232.