Development of mouse fibroblast cell line expressing human tau protein and evaluation of tau-dependent cytotoxity

A cell model has been developed to study the fundamental mechanisms of pathogenesis of Alzheimer’s disease (AD). The model is based on the 3T3-4R-tau cell line, clone 47, derived from the parental cell line NIH-3T3 (mouse fibroblasts) permanently expressing the human tau (4R) protein. Stable expression of the tau protein was confirmed by immunofluorescence assay (IFA) and characterized by Western blotting with monoclonal antibodies. Cytotoxicity of different forms of tau protein was estimated in the Transwell two-chamber coculture system involving 3T3-4R-tau cells and primary mouse hippocampal neurons. The data on the toxic effect of human tau protein expressed by 3T3 cells on the primary mouse neurons may be an indirect evidence of a similar scenario of pathological process development in human brain. The 3T3-4R-tau cell line makes it possible to simulate the conditions in human brain during AD and other neurodegenerative diseases more exactly than other cell models and can be used for the directed search of drugs inhibiting neurodegenerative processes.     

Carbohydrate Accumulation in Siberian Spruce Needles of Various Ages

The content of mono- and oligosaccharides, hemicelluloses, and water-soluble polysaccharides was studied in Siberian spruce (Picea obovata Ledeb.) needles of various ages. Accumulation of carbohydrates during the growth period and the ratio of their individual fractions were determined by the proportions between the growth rate and assimilate export in developing needles. Throughout the growth period, the content of monosaccharides in needles of all ages was much higher than that of oligosaccharides. Unlike the period of active growth, the dormancy period was characterized by a wider diversity of oligosaccharides and their rather high content. Hemicelluloses that accumulated during the previous growth season and water-soluble polysaccharides of 2- and 3-year-old needles were involved into metabolism at the time of active growth of current-year needles. Analysis of carbohydrate accumulation in 1- to 9-year-old needles showed that the monosaccharide concentration was higher in needles of the first two years. The content of hemicelluloses A and B and water-soluble polysaccharides was higher in older needles. During the growth period, the assimilates of 2- and 3-year-old needles were partly used for the formation of young needles. The increase in relative content of polysaccharides during needle senescence reflects the involvement of photosynthetic products into the secondary pool of carbon metabolites.     

Immunological approach to structural-functional mapping of the membrane receptors

In order to study the structural and functional specificity of different fragments of extracellular domains of the membrane receptors, their immunological blockade and analysis of changes in brain function in health and disease were carried out. Effects of the immunization against unstructured fragments of the neurotrophin receptor (p75 NTR) containing binding sites for a nerve growth factor, amyloid-beta, and proneurotrophin were studied. It was shown that immunization of NMRI mice with synthetic peptides with amino-acid residue sequences corresponding to the p75 NTR fragments 86–93 and 146–153 exerted an adverse effect both on the morpho-functional state of the cortical and hippocampal neurons and on the spatial memory of animals. In contrast, the immunization by the p75 NTR synthetic fragment 167–176 was accompanied by an improvement of these characteristics. The results of the structural-functional mapping of the extracellular domain in neuronal membrane receptors in vivo were in line with the published data of the X-ray analysis. The immunological approach developed in this work provides insight into the peculiarities of the receptor functioning in the course of the Alzheimer’s type neurodegeneration process and favors the development of effective immunological ways for selective therapy of the Alzheimer’s disease.