Disturbance of the Epithelial-Mesenchymal Transition as a Cause of the Defective Development of Human Spontaneous Abortions with Abnormal Karyotype.

Genetic program regulating epithelial-mesenchymal transition is activated at the early stages of embryogenesis. Abnormal karyotype of the embryo disrupts the fundamental process of epithelial-mesenchymal transition, which is seen from incomplete morphological rearrangement and reduced migration capacity of cells, as well as low level of expression of epithelial-mesenchymal transition markers (fibronectin, collagen, and glycosaminoglycans). Disturbances of the epithelial-mesenchymal transition affect the proliferative potential of cells with aberrant karyotype, which contributes to the delay of embryonic development and correlates with the formation of abnormal phenotype in carriers of chromosomal abnormalities.

[Study of protein products of gene expression in cells with altered chromosome sets for genetic mapping]. / Izuchenie belkovykh produktov gennoi ékspressii v kletkakh s izmenennym naborom khromosom dlia geneticheskogo kartirovaniia.

Two-dimensional electrophoresis was used for analyzing proteins in hybrid cells that contained single human chromosomes (chromosome 5, chromosome 21, or chromosomes 5 and 21) against the background of the mouse genome. By comparing the protein patterns of hybrid and parent cells (about 1000 protein fractions for each kind of cell), five fractions among proteins of hybrid cells were supposedly identified as human proteins. The genes of two of them are probably located on chromosome 5, and those of other three, on chromosome 21. Moreover, analysis of proteins in fibroblasts of patients with the cri-du-chat syndrome (5p-) revealed a decrease in the content of two proteins, as compared with those in preparations of diploid fibroblasts. This fact was regarded as evidence that two corresponding genes are located on the short arm of chromosome 5. Methodological problems associated with the use of protein pattern analysis in cells with altered chromosome sets for the purposes of genetic mapping are discussed.

Synthesis of glycosaminoglycans in fibroblasts from abortuses with trisomy, triploidy, and from children with Down's syndrome.

A comparative study has been made of glycosaminoglycan (GAG) accumulation in human fibroblasts with trisomy 7 and triploidy from spontaneous abortuses, fibroblasts with triploidy from induced abortuses, fibroblasts from patients with Down's syndrome and diploid fibroblasts from age-matched controls. The study demonstrated that the incorporation of [3H] glucosamine into hyaluronic acid by fibroblasts with trisomy 7 and triploidy, established from spontaneous abortuses, and from two out of three induced abortuses with triploidy, was 2.6-5.3 times lower than control incorporation. One strain of fibroblasts from an induced abortus with triploidy (IMG-1062) did not show any differences in GAG production when compared with diploid fibroblasts. However, the strains from children with Down's syndrome revealed normal or even increased levels of hyaluronic acid production. The data support the contention that the decreased hyaluronic acid synthesis in fibroblasts with an abnormal karyotype is related to spontaneous abortion.

[Contribution of lysosomal enzymes into degradation of short- and long-lived proteins in human embryonal fibroblasts with abnormal chromosome complement]. / Issledovanie vklada lizosomal'nykh fermentov v degradatsiiu korotko- i dolgozhivushchikh belkov émbrional'nykh fibroblastov cheloveka s anomal'nym naborom khromosom.

Degradation of short- and long-life proteins was studied in human embryonal fibroblasts with normal karyotype, trisomy and triploidy. Degradation of both short- and long-life proteins by means of lysosomal enzymes was elevated in fibroblasts with anomalous karyotype at the logarithmic phase of growth as compared with normal state, when lysosomotropic agent NH4Cl was used. In transition to stationary phase of growth participation of the lysosomal system in degradation of long-life proteins was increased in fibroblasts with normal karyotype, whereas degradation of these proteins in aneuploid fibroblasts maintained at the level found during the logarithmic phase of growth. Lysosomal enzymes did not participate apparently in degradation of short-life proteins in fibroblasts with normal and anomalous karyotype at both phases of growth. The data obtained suggest that chromosomal disbalance was related to impaired regulation of protein degradation as well as to possible alteration in the ratio of cytosol and lysosomal proteolysis.

[The ratio of collagens type I and III in cultures of human fibroblasts with diploid and aberrant chromosome complement]. / Sootnoshenie kollagena tipov I i III v shtammakh fibroblastnykh kletok cheloveka s diploidnym i anomal'nym naborom khromosom.

The ratio of collagens I/III was studied in human diploid, trisomic and triploid fibroblast strains. The following material was used in experiments: 5 strains obtained from human spontaneous abortuses (trisomy 7, trisomy 9, triploidy), 6 diploid embryonic strains, 4 strains from patients with Down syndrome, 3 strains from healthy children, 4 strains from healthy adult donors and 3 strains from very old persons (81-107 years old). Various types of collagen were separated by means of electrophoresis. Distinct ontogenetic alterations were not observed in content of collagen III in diploid and aneuploid human cultivated fibroblasts. However, considerable alterations in the ratio of collagens I/III correlated with genetic pathologies only in the patients examined.

[Cyclic AMP and cyclic GMP level in cells of spontaneously aborted fetuses with trisomic and triploid karyotypes]. / Uroven' tsAMF i tsGMF v kletkakh spontannykh abortusov s trisomnym i triploidnym kariotipom.

Contents of intracellular cAMP and cGMP were studied in cultivated fibroblasts from 4 spontaneous abortuses with trisomy 7 and trisomy 9 as well as in 4 triploid cell strains. Six diploid cell strains from medical abortuses were used as controls. Distinct increase in cAMP content both calculated per I mg of cell protein or per a cell was found in trisomic strains, whereas the cAMP content increase in triploid strains was detected only per a cell. The data obtained suggest that functions of membrane complexes were impaired in the cells with anomalous karyotype.

[Kinetics of protein degradation in diploid and trisomic human fibroblasts]. / Kinetika raspada belkov v diploidnykh i trisomnykh fibroblastakh cheloveka.

The degradation rate of long-lived and short-lived proteins was determined in diploid fibroblasts and fibroblasts with trisomy 7 derived from human embryos. Two fractions of proteins were detected in the exponentially growing diploid fibroblasts with half-lives (T 1/2) 37 and 19 hours. The rate of protein degradation increases in diploid fibroblasts as they approach confluence and protein fractions with T 1/2 30, 18 and 12 hours appear. The rate of protein degradation in trisomic fibroblasts does not change for the long-lived and short-lived proteins and is the same in both exponential (T 1/2 31 and 14 hours) and stationary phase (T 1/2 33 and 17 hours). The relative amount of the short-lived proteins in trisomic fibroblasts in the stationary phase decreased as compared with the one in diploid fibroblasts. It is apparent that a mechanism of regulation of protein catabolism in trisomic fibroblasts is impaired.

[14C-procollagen secretion by human embryonal fibroblasts with diploid and trisomic chromosome complement]. / Sekretsiia 14C-prokollagena émbrional'nymi fibroblastami cheloveka s diploidnym i trisomnym naborom khromosom.

Secretion of procollagen was studied in human embryonal fibroblasts with diploid chromosomes as well as in fibroblasts obtained from fetuses after spontaneous abortion from patients with trisomy by chromosome 7. The rate of procollagen secretion was approximately similar in these cells; the protein was shown to accumulate in intracellular matrix of diploid fibroblasts, while it did not occur in the matrix of aneuploid fibroblasts. Content of polymeric tubulin was decreased in fibroblasts with trisomy as compared with diploid cells. Impairment of the intracellular matrix structure in the cells with trisomy appears to be responsible for deterioration of morphogenesis in human chromosome anomalies.

Collagen and fibronectin synthesis by trisomic and triploid fibroblasts from human spontaneous abortuses.

Collagen and fibronectin synthesis by trisomic and triploid fibroblasts derived from human spontaneous abortuses was studied. It was demonstrated that the level of fibronectin and collagen production in fibroblasts with trisomy 7, trisomy 9, and triploidy was reduced as compared with diploid cells. A correlation between this observation and an increased rate of intracellular 14C-procollagen degradation was also established for the anomalous strains. No difference in hydroxylation of 14C-proline residues in alpha 1(I) and alpha 2(I) collagen chains and no fluctuation in the collagen type (I): type III ratio was found in the strains with the abnormal karyotypes. It was concluded that differentiation of the abnormal fibroblasts was impaired. The data also favour the hypothesis that the deficiency of the fibroblasts in producing proteins may account for a variety of anatomic abnormalities of embryos.

[Characteristics of intracellular metabolism of procollagen and other proteins in human embryo fibroblasts in trisomy for chromosome 7]. / Osobennosti vnutrikletochnogo metabolizma prokollagena i drugikh belkov v fibroblastakh émbrionov cheloveka s trisomiei po khromosome 7.

A comparative study of the relative rates of intracellular total protein metabolism in diploid and aneuploid (with trisomy for chromosome 7) human embryo fibroblasts in the logarithmic and stationary growth phases was carried out. Using double labeling with [14C]proline (24 hrs) and [3H]proline (3 hrs), it was found that: the rates of intracellular protein metabolism during transition to the stationary phase of growth are increased in diploid cells and decreased in cells with trisomy for chromosome 7; the relative rate of protein metabolism in the logarithmic phase is higher in trisomic cells than in diploid ones. The intracellular degradation of procollagen in trisomic cells is increased approximately by 17% as compared to normal fibroblasts. Treatment of cell lysates with bacterial collagenase revealed the presence of procollagen incomplete degradation products in anomalous fibroblasts. The observed differences in the rates and mode of protein metabolism during transition of diploid and trisomic fibroblasts to the stationary phase of growth suggest that the odd autosome interferes with the normal coordinated activity of genes in chromosomes.

[Various characteristics of the structure and synthesis of procollagens produced by cultured skin fibroblasts from patients with Danlos-Ehlers syndrome type I]. / Nekotorye kharakteristiki struktury i sinteza prokollagenov, produtsiruemykh kul'turami fibroblastov kozhi bol'nykh s sintromom Elersa-Danlo I tipa.

The electrophoretic mobilities of the collagen and procollagen type I and III chains synthesized by the fibroblasts isolated from patients with type I Ehlers-Danlos syndrome as well as a set of peptides obtained by splitting of pro alpha 1(I) and pro alpha 2(I) type I procollagens by cyanbromide are not different from the normal ones. The fact demonstrates the absence of long insertions or deletions, or the sufficient defects in intracellular chain modifications. The changes were also nor registered for the ratio of type I and III collagens from the digested by pepsin preparations of protein accumulating in the culture media of the cultured skin fibroblasts from patients. The studied strains of cultured fibroblasts from patients suffering the Ehlers-Danlos syndrome have the trend to increased accumulation of partially processed chains of proc alpha 1(I) and proc alpha 2(I) type I procollagen and to the increased ratio of pro alpha 1(I) to pro alpha 2(I).

[Detection of homozygotes and heterozygote carriers of GM2-gangliosidosis]. / Vyiavlenie gomozigot i geterozigotnykh nositelei GM2-gangliozidozov.

11 patients with Tay-Sachs disease (TSD) and 4 patients with Sandhoff disease were identified using the methods of heat inactivation of hexosaminidase at 50 degrees C (3 and 4 hours) and electrofocusing on PAG-plates in the pH range 3.5-9.5. Ion exchange chromatography on DEAE cellulose DE-52 proved to be reliable for identification of heterozygotes in cases when the proband was not available. The incidence of TSD gene was estimated in 2 population samples--from the cities of Gomel and Kostroma. It was about 0.004 in the Gomel sample. No heterozygotes were detected in Kostroma.

[Comparative characteristics of protein-synthesizing apparatus of diploid and aneuploid human embryo fibroblasts]. / Sravnitel'naia kharakteristika beloksinteziruiushchego apparata diploidnykh i aneuploidnykh fibroblastov émbrionov cheloveka.

The time of average polypeptide chain synthesis (tc), distribution of synthesized polypeptides according to their molecular masses, the ratio of translating and nontranslating ribosomes and polyribosomes of different size have been analyzed for diploid and aneuploid strains of fibroblasts. The magnitude of tc as well as the size of polypeptide chains synthesized were found to be similar for both kinds of fibroblasts. The relative cellular content of the translating ribosomes has been shown to decrease during the transition of cells from both strains to the stationary growth phase. The relative content of heavy polyribosomes is lower in aneuploid cells as compared with that in diploid cells. The process of translation in aneuploid fibroblasts is concluded to have no essential deviations from normal.

[Changes in fibronectin biosynthesis in human embryonal fibroblasts with trisomy for chromosomes 7 and 9]. / Izmenenie biosinteza fibronektina v émbrional'nykh chelovecheskikh fibroblastakh s trisomiei po khromosomam 7 i 9.

Biosynthesis of fibronectin in 2 strains of aneuploid human fibroblasts with trisomy by chromosomes 7 and 9 was about 2-fold decreased as compared with normal diploid fibroblasts. The most distinct decrease of the fibronectin biosynthesis was observed at the logarithmic phase of the cell culture growth. The cells with anomalous karyotype exhibited also the decreased rate of secretion of the impulse labelled fibronectin. The decrease in the rate of fibronectin and collagen production (main proteins of intercellular substance) in fibroblasts with the chromosomes anomalies might be responsible for irreversible impairments of the embryo development, resulting in spontaneous abortion.

Disturbances in collagen synthesis in trisomic cells from spontaneously aborted embryos.

Collagen synthesis in cells with trisomy 7 and 9 derived from human spontaneous abortuses was found to be lower (5.06% and 5.53% respectively) than in the control diploid cells (8.80%). The ratio of collagen types (I/III) in trisomic strains did not differ from the control data while the amount of the degraded procollagen in trisomic cells was increased.

[Absence of a gene dose effect for collagen type I and III in fibroblasts with trisomy of chromosome 7 from a spontaneously aborted human fetus]. / Otsutstvie éffekta dozy gena dlia kollagena tipa I i tipa III v fibroblastnykh kletkakh s trisomiei po khromosome 7, poluchennykh iz spontannogo abortusa cheloveka.

Collagen production was studied in human embryonal fibroblasts. Synthesis of collagen in the cells with trisomy 7 was decreased 2-fold as compared with diploid cells in spite of 50% increase of the collagen genes localized on the chromosome 7. Diploid and aneuploid cells synthesized collagens of the I and III types at similar weight ratios. At the same time, an increase in synthesis of type I collagen trimer was found in culture of cells with anomalous caryotype. A decrease of collagen production in cells with anomalous caryotype appears to be one of the reasons responsible for spontaneous abortion.