Обнаружен повышенный уровень нарушений эпигенетической регуляции экспрессии генов в трофобласте хориона спонтанных абортусов с трисомией 16. Среди гиперметилированных генов была значимо обогащена группа генов секретируемых белков, значительное количество генов кодировали рецепторы и транскрипционные факторы. Гиперметилирование выявленных генов является потенциальной причиной гибели эмбрионов с трисомией 16 на ранних стадиях развития. An increased level of abnormal epigenetic regulation of gene expression in the trophoblast of spontaneous miscarriages with trisomy 16 was found. Among the hypermethylated genes, the group of genes of secreted proteins was significantly enriched, and a significant number of genes encoded receptors and transcription factors. Hypermethylation of the identified genes is a potential cause of death of embryos with trisomy 16 in the early stages of development.

Проведен анализ выживаемости клеток, оценка уровня фокусов белков репарации ДНК и частоты радиационно-индуцированных микроядер в условиях дифференциальной экспрессии генов ADAMTS1, RBFOX2, THBS1 и WHSC1 в модельных системах in vitro и в лимфоцитах периферической крови человека. Полученные результаты указывают на потенциальную возможность использования уровня экспрессии данных генов для выявления индивидов с повышенной радиочувствительностью. In this study, we investigated the cell survival, the DNA repair foci level and the radiation-induced micronuclei frequency in the model systems in vitro and in the human peripheral blood lymphocytes with differential expression of ADAMTS1, RBFOX2, THBS1 and WHSC1 genes. The results indicate the potential opportunity of using these genes expression level to identify the individuals with increased radiosensitivity.

Митотическая нестабильность кольцевых хромосом может приводить к появлению клеточных клонов с различной генетической структурой. В качестве модели нестабильности кольцевых хромосом в митозе мы использовали фибробласты от пациентов с r(8), r(13), r(18) и r(22) и полученные из них индуцированные плюрипотентные стволовые клетки (ИПСК). Линии ИПСК с r(22) имели относительно стабильный кариотип на протяжении десятков (до 60) пассажей и сохраняли неизменную структуру кольцевой хромосомы. Кариотип линий ИПСК с r(8) и r(18) на ранних пассажах стабильный, планируется его изучение на поздних пассажах. Наибольшее разнообразие кариотипа выявлено в линиях ИПСК с r(13), в которых наблюдали различные перестройки и выраженную клеточную гетерогенность. Определение факторов, влияющих на митотическую стабильность кольцевых хромосом, может иметь значение для консультирования пациентов. Mitotic instability of ring chromosomes can lead to the appearance of cell clones with different genetic structure. IPSCs from fibroblasts of patients with r(8), r(13), r(18), and r(22) were used as a model of ring chromosomes mitotic behavior. Karyotypes of iPSC lines with r(8) and r(18) have so far been evaluated only in the early passages, lines with r(22) have maintained a relatively stable karyotype up to 60 passages. The occurrence of rearrangements and cellular heterogeneity was found characteristic for r(13) iPSCs. The determination of factors affecting the ring chromosomes mitotic stability would be beneficial for the patient’s prognosis.

Воздействие ионизирующего излучения вызывает значительные функциональные изменения в клетках человека, выражающиеся в активации различных сигнальных путей и транскрипционного ответа множества генов. Величина этих изменений вариабельна у разных индивидов, составляя феномен индивидуальной радиочувствительности. В обзоре рассматриваются известные маркеры индивидуальной радиочувствительности человека, начиная от цитогенетических, позволяющих непосредственно оценить эффективность репарации радиационно-индуцированных повреждений ДНК в клетках, до маркеров, выделенных на основании полногеномных и полнотранскриптомных исследований дифференциально экспрессирующихся генов, обусловливающих различные аспекты клеточного и организменного ответа на радиационное воздействие. Exposure to ionizing radiation causes significant functional changes in human cells which lead to activation of various signaling pathways and transcriptional response of many genes. The magnitude of these changes is variable for different individuals, making the phenomenon of individual radiosensitivity. In the review, markers of individual radiosensitivity are described ranging from cytogenetic markers for assessing the efficiency of DNA repair of radiation-induced damage in cells to genome- and transcriptome-wide approaches to identify differentially expressed genes that determine various aspects of response to radiation exposure.

The sex ratio in the first trimester of pregnancy shifts toward males due to increased elimination of female embryos. One reason for this phenomenon may be disruption of X chromosome inactivation. In this paper, we have analyzed the nature of the X chromosome inactivation in extraembryonic tissues of induced and spontaneous abortuses with 46,XX karyotype. Both equiprobable and asymmetric inactivation have been found in chorionic cytotrophoblast from spontaneous and induced abortuses. In the extraembryonic mesoderm of the control group of embryos, only equiprobable inactivation has been found, whereas this parameter was shifted in 15% of spontaneous abortions. The highest incidence of the selective inactivation of one of the parent homologues was found in the group with a lack of development of embryos and embryos from women with recurrent miscarriages. One of the reasons for the observed results can be compartmentalization of cells in the blastocyst leading to the nonrandom redistribution of cells and the predominance in the inner mass of cells with an active X chromosome with aberrations incompatible with normal embryonic development.

Effects of ionizing radiation registered in cells after low dose irradiation are still poorly understood. A pulsed mode of irradiation is even more problematic in terms of predicting the radiation-induced response in cells. Thus, the aim of this paper was to study and analyze the effects of dose and frequency of pulsed X-rays on the frequency of radiation-induced DNA double-strand breaks and their repair kinetics in human peripheral blood lymphocytes in vitro. Analysis of radiation-induced gammaH2AX and 53BP1 repair foci was used to assess the DNA damage in these cells. The dose-response curve of radiation-induced foci of both proteins has shown deviations from linearity to a higher effect in the 12-32 mGy dose range and a lower effect at 72 mGy. The dose-response curve was linear at doses higher than 100 mGy. The number of radiation-induced gammaH2AX and 53BP1 foci depended on the frequency of X-ray pulses: the highest effect was registered at 13 pulses per second. Moreover, slower repair kinetics was observed for those foci induced by very low doses with a nonlinear dose-response relationship.

Assessment of genetic risks related to effects of ionizing radiation on the human body remains a topical problem in medical genetics. Along with numerous data about the influence of radiation on chromosomes of man and model organisms, there are some facts suggesting possible aneugenic effect in addition to the well-known clastogenic influence generally recognized as a marker for biological dosimetry. The interest in genetic risks of aneuploidy is in the first place due to its gross mutagenic potential. Simultaneous changes in a large number of gene copies are regarded as an important contributing factor of malignant cell transformation and tumour growth. The role of aneuploidy in aging and multifactorial diseases is discussed and some data suggesting aneugenic effect of ionizing radiation are presented. The potential significance of aneuploidy for risk assessment of mutagenic factors is considered.

The analysis of plutonium production factors has been carried out by using two methodical approaches: assessment of chromosomal aberrations level in routine and G-banded metaphases and molecular-cytogenetic investigation of aneugenic/clastogenic damages in cytokinesis-block binuclear lymphocytes by FISH with centromere specific DNA probes. The obtaining data point out for the first time about both aneugenic and clastogenic influences of incorporated 239Pu with activity range from 0.37 to 6.95 kBq. Correlation analysis of chromosome aberrations with cytome abnormalities allowed finding significant connection between number parameters of metaphase and interphase approaches. The results of this study support the suggestion that aberrant chromosomes are involved preferable in aneugenic events. The FISH technique in binucleated cytokinesis-blocked lymphocytes allows extending of detecting spectrum of chromosome damages and glance of aneugenic mechanisms. Correlations between metaphase and interphase-FISH results point out a high sensitivity of FISH cytome assay, which could be used as an independent test for detection both clastogenic and aneugenic environment influences.