[Structural changes in human brain tissue during prenatal alcoholization at different stages of intrauterine development]. / Strukturnye izmeneniya v tkani golovnogo mozga cheloveka pri prenatal'noi alkogolizatsii na raznykh srokakh vnutriutrobnogo razvitiya.

OBJECTIVE: To assess the degree of influence of intrauterine alcoholization on the formation of various structural components of the brain of human embryos. MATERIAL AND METHODS: Twenty-six samples of embryonic material from 8 to 11 weeks of intrauterine development were studied. The material was divided into four subgroups in accordance with the gestational age (Control 1 - 8-9 weeks of gestation and Control 2 - 10-11 weeks of gestation) and the history of the mother (presence or absence of the diagnosis «Alcoholism stage I-II¼ in the anamnesis). Morphometry was subjected to semi-thin sections stained by Nissl. The diameter and area of each individual tissue element (neuroblasts, glioblasts, vessels of the microvasculature, as well as the determination of the specific area (the ratio of the total area of the studied structure to the area of the entire section) and the calculation of the average number of these structures per unit area of the section, were determined. The AxioVision 4.8 program (Carl Zeiss, Germany) was used for analysis, and the Mann-Whitney test was used for statistical analysis of differences between the samples (significant differences, p<0.05). RESULTS: An insufficient increase in the area of vessels of the microvasculature was revealed in combination with a compensatory increase in their number per unit area of the section in the Alcohol groups compared with intact groups (48.5 µm2 vs 83.3 µm2, p<0.05). When comparing the sizes of glioblasts in the Control and Alcohol subgroups at different stages of development, a lag in the sizes of cellular structures in the Alcohol groups at the initial stages was revealed (average area 21.3 µm2 vs 32.1 µm2; 12.9 µm2 vs 13.3 µm2). When comparing data on later periods, no significant differences were found, only an increase in the specific number of cells in subgroup Alcohol 2 was noted (p<0.05). In neuroblasts, there was also a decrease in cell size with an increase in gestational age both among the Control and among the Alcohol subgroups. However, the cell sizes in Alcohol 2 exceeded those in Control 2 and their number was smaller (p<0.05). CONCLUSION: Alcohol leads to changes in the size and number of neuroblasts, glioblasts and vessels of the microvasculature and, as a result, to a disproportionate development of the entire brain tissue. The changes progress with an increase in the development period.

Expression of the NUP153 and YWHAB genes from their canonical promoters and alternative promoters of the LINE-1 retrotransposon in the placenta of the first trimester of pregnancy.

The placenta has a unique hypomethylated genome. Due to this feature of the placenta, there is a potential possibility of using regulatory elements derived from retroviruses and retrotransposons, which are suppressed by DNA methylation in the adult body. In addition, there is an abnormal increase in the level of methylation of the LINE-1 retrotransposon in the chorionic trophoblast in spontaneous abortions with both normal karyotype and aneuploidy on different chromosomes, which may be associated with impaired gene transcription using LINE-1 regulatory elements. To date, 988 genes that can be expressed from alternative LINE-1 promoters have been identified. Using the STRING tool, genes (NUP153 and YWHAB) were selected, the products of which have significant functional relationships with proteins highly expressed in the placenta and involved in trophoblast differentiation. This study aimed to analyze the expression of the NUP153 and YWHAB genes, highly active in the placenta, from canonical and alternative LINE-1 promoters in the germinal part of the placenta of spontaneous and induced abortions. Gene expression analysis was performed using real-time PCR in chorionic villi and extraembryonic mesoderm of induced abortions (n = 10), adult lymphocytes (n = 10), spontaneous abortions with normal karyotype (n = 10), and with the most frequent aneuploidies in the first trimester of pregnancy (trisomy 16 (n = 8) and monosomy X (n = 6)). The LINE-1 methylation index was assessed in the chorionic villi of spontaneous abortions using targeted bisulfite massive parallel sequencing. The level of expression of both genes from canonical promoters was higher in blood lymphocytes than in placental tissues (p < 0.05). However, the expression level of the NUP153 gene from the alternative LINE-1 promoter was 17 times higher in chorionic villi and 23 times higher in extraembryonic mesoderm than in lymphocytes (p < 0.05). The expression level of NUP153 and YWHAB from canonical promoters was higher in the group of spontaneous abortions with monosomy X compared to all other groups (p <0.05). The LINE-1 methylation index negatively correlated with the level of gene expression from both canonical (NUP153 - R = -0.59, YWHAB - R = -0.52, p < 0.05) and alternative LINE-1 promoters (NUP153 - R = -0.46, YWHAB - R = -0.66, p < 0.05). Thus, the observed increase in the LINE-1 methylation index in the placenta of spontaneous abortions is associated with the level of expression of the NUP153 and YWHAB genes not only from alternative but also from canonical promoters, which can subsequently lead to negative consequences for normal embryogenesis.