[Possible role of autophagy activation in the stimulation of regeneration].

Human cell senescence occurs unevenly and senescent cells in tissues frequently can disturb the function of neighbouring nonsenescent ones. Setting of tissues regeneration can have profound practical significance in medicine, especially in geriatrics. One of the approaches to solve the problem is selective elimination of senescent and damaged cells from the tissues that can be the first phase of the process.

Effect of 3D Cultivation Conditions on the Differentiation of Endodermal Cells.

Cellular therapy of endodermal organs is one of the most important issues in modern cellular biology and biotechnology. One of the most promising directions in this field is the study of the transdifferentiation abilities of cells within the same germ layer. A method for anin vitroinvestigation of the cell differentiation potential (the cell culture in a three-dimensional matrix) is described in this article.

[Differential and morphogenetic potential of rat dermal papilla cells].

Dermal papilla (DP) cells were isolated from rat vibrissae and put into a culture. The homogeneity of the obtained culture was confirmed using immunohistochemical staining with antibodies specific for this type of cell extracellular matrix protein (versican) and staining for alkaline phosphatase. It was demonstrated that the rat vibrissae DP cell culture participates in the development of hair follicles de novo.

[Self-synchronization of the protein synthesis rhythm in HaCaT cultures of human keratinocytes].

In cultures of human keratinocytes HaCaT contained in a serum-free medium on glass, a circahoralian rhythm of protein synthesis was found similar to the one in hepatocytes in vitro. The intensity of the synthesis was determined by the inclusion of 3H-leucine corrected for the pool of free marked leucine. Rhythm was studied in washed 1- or 2-day cultures after the change of the medium.

[Culture of human amniotic fluid stem cells in 3D collagen matrix].

Most of the researchers attribute amniotic fluid stem cells (AF SCs) to mesenchymal stem cells (MSCs). However, AF SCs express both mesenchymal and epithelial markers, which distinguishes them from postnatal MSCs. Cultivation in the three-dimensional matrix provides a different look at the nature of these cells.

[Cultivated human hair follicle cells are capable of integrating to skin structure in vivo].

In the present study, human keratinocytes and dermal papilla cells were labeled to investigate their behaviour after intradermal transplantation. Cells were transduced by lentiviral vectors that bore marker gene encoding green fluorescent protein (copGFP) or red fluorescent protein (DsRed). A portion of transgene expressing cells was evaluated by flow cytometry.

[Stem cell self-renewal: the role of asymmetric division].

Asymmetric division occurs widely in different groups of organisms from single-celled to insects, mammals, and plants. The operation of asymmetrical division may differ widely in different organisms. In multicellular organisms, asymmetrical division is one of the essential features of stem cell biology.

[Effect of growth factors on morphogenesis of human keratinocytes in vitro].

The effect of some growth factors on morphogenetic processes in the primary culture of human epidermal keratinocytes was studied in the model of formation of tubule-like structures in collagen gel. Culturing of keratinocytes in the presence of IGF and bFGF did not induce growth of tubule-like structures, whereas EGF, KGF, and HGF promoted the growth of three-dimensional epidermal outgrowths whose shape and size varied depending on the growth factor used.

[Comparison of fibroblasts-like cell differentiation capacities of human bone marrow, adipose tissue, hair papilla and dermal fibroblasts].

We compared the morphology and differentiation characteristics of the human cells from bone marrow, adipose tissue, hair papilla and skin dermis. All cell types showed fibroblastic morphology. Immunofluorescent analysis showed that adipose tissue derived stem cells (ADAS) and hair papilla cells (HPC) expressed CD105, CD49d and STRO-1, bone marrow mesenchymal stem cells (BMSC) were absent for CD49, dermal fibroblasts (DFb) expressed CD49 and STRO-1 at low level.

[SP phenotype of stem cells].

The paper analyzes wide range of studies which used the ability of stem cells to exclude vital dyes Rhodamin 123 and Hoechst 33342 as a marker. Data suggest that this marker reflects phenotypical differences between stem cells fractions but is not a characteristic of sternness.

[Specific features of satellite cells and myoblasts at different stages of rat postnatal development].

A cell culture consisting mainly of satellite cells and mononuclear myoblasts was derived from femoral muscles of infant (aged 3-7 days) and adult rats. Satellite cells identified by expression of the specific marker Pax7 accounted for approximately 80% of the isolated cell fraction. Mononuclear myoblasts represented by proliferating and postmitotic cell pools were identified immunocytochemically by the expression of markers Ki67 and desmin.

[Maintenance of genetic information in stem cells].

The available data on DNA cosegregation in some stem cells are reviewed. Cairns was the first to assume cosegregation of template DNA strands for adult stem cells; i.e.

[Epithelial tissue reconstruction using cell technologies].

The issue of the cellular basis of epithelial tissue engineering, concerning the skin first of all, is discussed. Principles of cultivating human epidermal keratinocytes and formation of living tissue equivalents for grafting to damaged tissues and organs are described. The article presents data on the restoration of damaged tissues after tissue equivalent grafting.

[Polarization and asymmetric division of stem cells].

Asymmetric cell division observed in many groups of organisms has similar mechanisms suggesting conservatism of the process. Asymmetric division of stem cells that reside in their niches is aimed to regulation of cell proliferation and genome stability maintenance. But stem cells may also divide symmetrically depending on situation.

[Expression and function of p63 gene in epithelial cells].

The presented data indicate that the p63 gene is required for the commitment of epidermal stem cells in embryonic development. At the same time, p63 underlies many functions involved in the self-renewal of stem cells in the adult epidermis. Its expression provides for keratinocyte adhesion, inhibits apoptosis, and maintains the integrity of the epidermal tissue.

[Stem cell niches].

The nature of the stem cell niche and its interaction with stem cells is one of fundamental problems in the biology of stem cells. Stem cell niches are formed during ontogeny. A niche can remain vacant and exist independently of stem cells; however, stem cell self-renewal cannot be maintained for long periods outside of the niche except for particular conditions, e.

[Population structure of in vitro cultured keratinocytes].

Analysis of behavior of isolated epidermal keratinocytes demonstrated two dominant processes within the first two days of cultivation: formation of cell aggregates and their adhesion to the substrate. Keratinocyte spreading increased in the attached aggregates, where densely packed and well spread cells could be recognized in the aggregate center and periphery, respectively. Cell spreading and proliferation was observed in the following days.

[Structural-functional units of epidermis].

The available data suggest that epidermis is organized in discrete structural and functional units (SFUs) reproduced both in vivo and in vitro. SFUs are formed in a culture of epidermal keratinocytes by self-organization of the forming cellular elements. SFUs are capable of self-sustaining and form a niche for the stem cells.

[Fibroblasts stimulate epithelialization of collagen gel].

We studied the influence of human embryonic fibroblasts on epithelialisation of collagen gel. Introduction of the fibroblasts into the gel stimulates proliferation of keratinocytes plated on the gel surface. The presence of fibroblasts in the gel also affects the pattern of keratinocyte migration on the gel and induces pronounced polarization of the migrating colonies.

[Simulation of the migration process of human epidermal keratinocytes over three-dimensional collagen gel].

We developed a novel model for studying migration of keratinocyte colonies over 3D collagen gel. It was shown that keratinocytes previously cultured on plastic and then seeded on the surface of collagen gel proliferate more actively than the primary cells. The gel density could significantly affect the morphology and migration of keratinocyte colonies.

[Production of recombinant human keratinocyte growth factor in Escherichia coli cells].

Here we describe the synthesis of the gene encoding human keratinocyte growth factor (hKGF) and the construction of vectors for cytoplasmic production of hKGF in Escherichia coli cells. The level of recombinant protein expression was 1-1.5% of the total cell protein.