Expression of Ext1, Ext2, and heparanase genes in brain of senescence-accelerated OXYS rats in early ontogenesis and during development of neurodegenerative changes.

Heparan sulfate (HS) and heparan sulfate proteoglycans (HSPG) play a significant role in brain development, and their structural and quantitative changes are revealed during aging and in neurodegenerative disorders. The mechanism of these changes is not clear, but is likely to be associated with alteration in the expression and/or activity of enzymes responsible for HSPG biosynthesis and degradation. The contents of mRNAs of the genes Ext1 and Ext2 encoding polymerization enzymes and of gene Hpse of heparanase degrading HS were determined in the brain of prematurely aging OXYS rats during early postnatal development and during appearance of signs of brain accelerated aging (at age of 1, 7, 14, 30, 60, and 420 days). Wistar rats of the same age were used as controls. Expression levels of the genes Ext1, Ext2, and Hpse in the brain of rats of both strains were maximal during the two first weeks of life, and the contents of mRNAs of all genes in the brain of newborn and 7-day-old OXYS rats were significantly higher than in Wistar rats. By the 14th day of life the differences leveled, but at the age of 30 days on the background of a decrease in the contents of mRNAs of Ext1, Ext2, and Hpse in OXYS rats they became more pronounced (three-, four-, and twofold, respectively). Differences between the strains were absent at the age of 60 days and 14 months, and expression of all the genes was significantly lower than in the newborn animals. A strong positive correlation was found between contents of mRNAs of all the studied genes, and this suggested that heparanase should be involved in HSPG metabolism together with Ext1 and Ext2. Based on these and earlier findings, we conclude that development of the OXYS rat brain occurs on the background of significant alterations in HSPG metabolism that precede the development of neurodegenerative manifestations recently detected by magnetic resonance imaging.

Brain proteoglycans in postnatal development and during behavior decline in senescence-accelerated OXYS rats.

Proteoglycans (PG) are involved in the brain development as well as in the pathogenesis of age-related neurodegenerative disorders but underlying mechanism remains poorly understood. We showed that senescence-accelerated OXYS rats are suitable model of age-related cerebral dysfunctions. Here the content and composition of PG in the postnatal development and during behavioral decline were examined in the brain of OXYS and Wistar(control) rats at the ages of 1, 7, 14 days and 1, 2 and 14 months. Thereafter behavior in open field (OF) and elevated plus maze (EPM) was investigated. Data confirmed the absence of differences in the performance in tasks between Wistar and OXYS rats at the age of 1 month and showed faster age-related anxiety-like behavior decline in OXYS rats. The distribution of PG and the extent of their sulfation undergo dramatic and rapid changes in the brain during postnatal development both in Wistar and OXYS rats. Significant differences in these parameters appeared in the period of development of behavioral decline in OXYS rats. In contrast, no interstrain differences were revealed in the content and composition of PG in 14-month-old rats when behavior deteriorations are already developed. The results suggest that behavioral deterioration in OXYS rats occurs against the background of altered composition, quantity and glycosaminoglycans (GAG) sulfation.

Age-related changes in proteoglycan composition in rat brain.

Brain proteoglycans play an important role in learning and memory processes and in the pathogenesis of neurodegenerative disease. Brain proteoglycans in Wistar rats and early aging OXYS rats at the age of 1, 2, and 14 months were compared. Proteoglycan content in OXYS rats aged 1 and 2 months is 2-fold lower than in Wistar. The content of proteoglycans 7-fold decreases in Wistar and OXYS rats with age at the expense of heparan sulfates and chondroitin sulfates and by the age of 14 months, the difference between the strains is leveled. These results indicate that cognitive and emotional disorders observed in OXYS rats by the age of 3 months develop against the background of significant changes in the content and composition of proteoglycans.

Expression of different proteoglycans in human breast tumors.

The composition of proteoglycans and their changes during malignant transformation are important factors influencing adhesive properties and mitotic activity of tumor cells. In this study, expression level of different proteoglycans (decorin, syndecan-1, lumican, glypican-1, and aggrecan) in tumors and normal human breast tissue was investigated. Multiplex RT-PCR data revealed different expression changes for different proteoglycans in human breast tumors--syndecan expression was activated compared to almost no expression in normal breast tissue, expression of decorin and lumican decreased 2-5- and 2-3-fold, respectively, and aggrecan transcription seems to be unaffected. A change of expression level of decorin correlated with expression of D-glucuronyl-C5-epimerase, a key enzyme responsible for the biosynthesis of idurone-containing glycosaminoglycans, possessing antimitotic activity. The results suggest that changes in decorin, lumican, and syndecan-1 expression in tumor tissue could induce a distortion of proteoglycan composition and mitotic activity of cells in human breast tumor.

Proteoglycans and human breast cancer.

Comparative analysis of proteoglycans in the control and tumor tissue of human mammary gland revealed disorders in the biosynthesis of dermatan sulfate proteoglycans in tumor cells. Using the methods of reverse transcription-PCR and Western blotting for the analysis of decorin expression we showed that these disorders were paralleled by reduced expression of the core protein and changes in the structure of proteoglycan carbohydrate chains and could be a cause of malignant degeneration of mammary gland cells.

Glycosaminoglycans of the vertebral body growth plate in patients with idiopathic scoliosis.

The concentrations of keratan sulfates and unmodified keratan sulfates increased in the vertebral body growth plate in patients with idiopathic scoliosis. Sulfation and acetylation of total glycosaminoglycans decreased by 50 and 30%, respectively. These changes reflect the decrease in biological activity of molecules that modulate function of the growth plate.

Proteoglycan composition in cell nuclei of mouse hepatoma.

Cell nuclei of mouse hepatoma contain various proteoglycans (PG) which include heparan sulfate proteoglycan (HS-PG), dermatan sulfate proteoglycan (DS-PG), and chondroitin sulfate proteoglycan (CS AC-PG). The latter is not found in cell nuclei of normal mouse liver. Heparan sulfate (HS) and dermatan sulfate (DS) are the main constituents of carbohydrate chains of nuclear proteoglycans of tumor and normal cells, respectively. Changes in the composition of nuclear PG during malignant transformation are discussed considering the concept of their possible involvement in the regulation of cell mitotic activity.

[Nuclear proteoglycans from mouse liver cells: isolation and identification]. / Iadernye proteoglikany kletok pecheni myshei: vydelenie i identifikatsiia.

Proteoglycans (PG) have been isolated from mouse liver nuclei and identified. Nuclear PG are represented by various classes: i) PG containing dermatan sulfate (DS) chains; ii) PG containing heparan sulfate (HS) chains and, apparently, iii) mixed PG whose protein core contains both DS and HS chains.

[Comparative evaluation of the glycosaminoglycan composition in plasma membranes of normal and transformed mouse liver cells]. / Sravnitel'noe issledovanie sostava glikozaminoglikanov v plazmaticheskikh membranakh normal'nykh i transformirovannykh kletok pecheni myshei.

Using electrophoresis in agarose gel, a comparative study of composition of membrane-bound glycosaminoglycans (GAG) from normal mouse liver cells and from o-aminoazatoluene-induced mouse hepatoma cells was carried out. Differences in the composition and localization of GAG were revealed. The plasma membrane fraction of hepatoma cells contained no GAG; the bulk of GAG (approximately 98%) was localized in the plasma membrane free fraction. Within this fraction GAG contained no heparan sulfates with a high electrophoretic mobility that were detected in plasma membranes of normal liver cells. The possible involvement of proteoglycans bound to cell surface in transmembrane signal transfer is discussed.

[Antitumor effectiveness of chalone-like proteoglycans isolated from normal and tumor tissues]. / O protivoopukholevoi éffektivnosti keilonopodobnykh proteoglikanov, vydelennykh iz normal'nykh i opukholevykh tkanei.

Chalone-like proteoglycans (PG) have been isolated from 22a hepatoma, spontaneous adenocarcinoma of the mammary gland of C3H/He mice and from transplanted X-ray-induced lymphoma in C57Bl mice. It has been found that the biological activity of these PG was considerably weaker than that of PG taken from the liver, mammary gland and spleen of cattle. PG from 22a hepatoma produced a weaker tissue-specific antimitotic effect as against PG from the liver when acting on the liver cells of 6-day C57Bl mice, while the lymphoma PG under these conditions was ineffective. PG from the liver and mammary gland inhibited the growth of certain transplanted tumours in vitro. The lymphoma PG has stimulated the tumour growth.

[Composition and degree of sulfation of glycosaminoglycans from tissues of different animal species: heterogeneity and tissue specificity of heparan sulfates]. / Sostav i stepen' sul'fatirovaniia glikozaminoglikanov iz tkanei zhivotnykh raznykh vidov: geterogennost' i tkanevaia spetsifichnost' geparansul'fatov.

The composition and degree of sulfation of glycosaminoglycans (GAG) in proteoglycans from various animal tissues were studied. It was shown that sulfated GAG contain chondroitin sulfates AC and B as well as heparan sulfates. The bulk of GAG in the majority of tissues under study is represented by 2-3 types of heparan sulfate molecules differing in the degree of sulfation. According to the degree of sulfation heparan sulfates from all tissues studied can be classified into three groups. Homologous tissues of various animal species are characterized by a similar composition and the degree of sulfation The data obtained are discussed in terms of the feasible role of proteoheparan sulfates in specific cell-to-cell interactions.

[Comparative characteristics of the composition and degree of sulfation of glycosaminoglycans in resting and actively proliferating tissues]. / Sravnitel'naia kharakteristika sostava i stepeni sul'fatirovaniia glikozaminoglikanov pokoiashchikhsia a aktivno proliferiruiushchikh tkanei.

A comparative study of the composition and degree of sulfation of glycosaminoglycans (GAG) in proteoglycans isolated from normal animal tissues and from actively proliferating embryonic, tumour and regenerating tissues was carried out. Significant differences in the ratios of various types of sulfated GAG were revealed. The relative content of chondroitin sulfate AC in actively proliferating tissues was considerably increased. It was found that all types of sulfated GAG in actively proliferating tissues, with the exception of regenerating tissue, are characterized by a lower degree of sulfation as compared to GAG from resting tissues. The experimental results are discussed in terms of the role of proteoglycans in the organization of extracellular matrix and in control of cell proliferation.

[Proteoglycans of animal tissue and their effect on DNA synthesis]. / Proteoglikany zhivotnykh tkanei i ikh vliianie na sintez DNK.

A procedure for isolation of proteoglycans (PG) from rat liver and lung has been developed. The effect of PG on DNA and RNA synthesis in fragments of mouse embryo tissue was investigated. PG were shown to inhibit DNA synthesis. This effect was tissue-specific but species-nonspecific. Under the same conditions various glycosaminoglycans (chondroitin sulfates and heparin) had no effect on DNA synthesis. No effect of PG on RNA synthesis was observed. Possible mechanisms of PG effect are discussed.

[Comparison of the composition of proteoglycans isolated from intact and regenerating rat livers]. / Sravnenie sostava proteoglikanov, vydelennykh iz intaktnoi i regeneriruiushchei pecheni krysy.

Using electrophoresis on acetate-cellulose membranes, the composition of proteoglycans from intact and regenerating rat liver was compared within the first 24 hours after partial hepatectomy. It was found that proteoglycan preparations from intact and regenerating liver contain five fractions corresponding to proteoheparan sulfates I, II and III, proteochondroitin sulfate B and proteochondroitin sulfate AC. Two-phase reciprocal changes in the content of proteoheparan sulfates I and II took place during regeneration. On the 6th and 15th hours after partial hepatectomy, the proteoheparan sulfate I content was maximal, while that of proteoheparan sulfate II is minimal; the maximum content of proteoheparan sulfate II and the minimum content of proteoheparan sulfate I were observed on the 12th hour. Since the maxima of reciprocal changes in the proteoheparan sulfates I and II levels coincide with the activation of liver DNA transcription preceding DNA replication as well as with the relatively synchroneous outburst of mitotic activity, it was assumed that proteoheparan sulfates play a regulatory role in cell proliferation.

[Biological activity of chalone-like proteoglycans during ontogeny]. / Biologicheskaia aktivnost' keilonopodobnykh proteoglikanov v protsesse ontogeneza.

A chalone-like proteoglycan was isolated from the liver of 2 and 24 month old cattle and Wistar rats which inhibited mitoses in the liver cells of C57BL mice starting from 5-6 days after birth. The effect of this proteoglycan was tissue but not species specific. We failed to isolate this proteoglycan from the liver of newborn rats, thus suggesting that either this substance is not produced by the cells of newborn animals or is produced in insignificant quantities. The proteoglycan isolated from the liver of the old rats, unlike that from the liver of 2 month old rats, was not effective in the same doses and this suggests changes in its chemical composition.