[Preparation stimulating hair growth possibly acts by inhibiting hair follicle ageing experiments on mice and transcriptome analysis].

Preparation stimulating hair growth (PSHG) was studied on mice of various strains (Balb/c, CBA, C57BI/6, and outbred). It was shown that a long-term (44 months) application of PSHG does not reliably affect the appearance of young healthy mice but does induce increase in the hair follicle size. No adverse consequences of the PSHG application were observed. Naturally occurring propagating regenerative hair waves peculiar to mice were preserved. In older mice (more than 2 years) with signs of alopecia, application of PSHG caused an overgrowing of bald patches within two months. Transcriptome analysis of the PSHG effect performed in fibroblast cell culture showed that PSHG stimulates processes of tissue development and remodeling. These observations together with previous findings showing that PSHG stimulates autophagy and induces death of cells subjected to oxidative stress may suggest that the mechanism of the PSHG effect involves stimulation of regeneration of skin and its derivatives owing to more efficient elimination of senescent and damaged follicle cells.

[Stimulation of proliferation by carnosine: cellular and transcriptome approaches].

Concentration of endogenous dipeptide carnosine in human muscle tissue reaches tens of millimoles. For more than 100 years of research, a lot of data concerning carnosine functions were accumulated, among which anti-aging effects are regarded most important. Heire, effect of carnosine in cell cultures was studied. It has been found that apart from the known action--an increase of the Hayflick limit and morphological rejuvenation--carnosine stimulates cell division in colony-forming assays and in the course of transition of cells to the quiescent state. The analysis of the transcriptome showed that carnosine-induced changes are mainly related to positive regulation of the cell cycle at all levels, from the onset of the DNA synthesis to chromosome condensation. One can suppose that the revealed stimulation of the cell cycle account for the carnosine-induced rejuvenation processes and a high concentration ofcarnosine in muscle tissue is required for the muscle recovery (regeneration) after excess loads.

[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. During the investigation of the mechanisms of action of the preparation for hair growth stimulation it was discovered that this preparation does not stimulate proliferation of various human cells and does not increase the resistance of cells to stress. On the contrary the preparation becomes cytotoxic at the conditions of oxidative stress although on its own account it did not induce elevation of production of reactive oxygen species. Further investigations showed that the preparation increases transcriptional activity of p53 gene, increase autophagy level and induce weak adipogenic differentiation. The hypothesis of autophagic regeneration is discussed. As a result, the selective autophagic cell death of any senescent and damaged cells that undergoes oxidative stress triggers the regeneration process which can be increased by both the rejuvenation effect of increased autophagy and at the expense of nutrients released during the autophagy.

Comparative analysis of expression of human telomerase catalytic subunit at the transcription level in cell cultures of different origin.

The expression of human telomerase catalytic subunit in HL-60 and HT-1080 malignant transformed cells and telomerized fibroblasts was studied by quantitative PCR. It was found that the number of transcripts of human telomerase catalytic subunit per cell in telomerized fibroblasts could be hundreds of times higher than in HL-60 and HT-1080 cells. Telomerized fibroblast cultures are suggested as experimental systems for selection of basal compounds for creation of anticancer drug prototypes, the molecular target of which is human telomerase catalytic subunit. The effects of human telomerase catalytic subunit expression on the fibroblast proteome are analyzed.

[Enhanced control of proliferation in telomerized cells].

Clones of telomerized fibroblasts of adult human skin have earlier been obtained. It was shown that despite their fast growth in mass cultures, these cells poorly form colonies. Conditioned medium, antioxidants, and reduced partial oxygen pressure enhanced their colony formation, but not to the level characteristic of the initial cells. The conditioned medium of telomerized cells enhanced colony formation to a much greater extent than that of the initial cells. A study of proteome of the telomerized fibroblasts has revealed changes in the activities of tens of genes. A general trend consists in weakening and increased lability of the cytoskeleton and in activation of the mechanisms controlling protein degradation. However, these changes are not very pronounced. During the formation of immortal telomerized cells, selection takes place, which appears to determine changes in the expression of some genes. It was proposed that a decrease in the capacity of telomerized cells for colony formation is due to increased requirements of these cells to cell-cell contacts. The rate of cell growth reached that characteristic of mass cultures only in the largest colonies. In this respect, the telomerized fibroblasts resembled stem cells: they are capable of self-maintenance, but "escape" to differentiation in the absence of the corresponding microenvironment (niche), which is represented by other fibroblasts. Non-dividing cells in the test of colony formation should be regarded as differentiated cells, since they have no features of degradation, preserve their viability, actively move, grow, phagocytized debris, etc. It was also shown that telomerization did not prevent differentiation of myoblasts and human neural stem cells. Thus, the results obtained suggest the existence of normal mechanisms underlying the regulation of proliferation in the telomerized cells, which opens possibilities of their use in cell therapy, especially in the case of autotransplantation to senior people, when the cell proliferative potential is markedly reduced and accessibility of stem cells is significantly restricted.

[Telomerization as a method of obtaining immortal human cells preserving normal properties]. / Telomerizatsiia--sposob polycheniia immortal'nykh kletok cheloveka, sokhraniaiushchikh normal'nye svoistva.

Most human somatic cells have no telomerase activity. This leads to terminal underreplication of chromosomes and, hence, proliferative ageing of cells. We studied the consequences of introduction of the gene of the catalytic component of human telomerase hTERT in the normal fibroblasts of adult human skin. The expression of this gene led to the appearance of telomerase activity in the fibroblasts, elongation of telomeres (to the size characteristic of the embryonic cells), and immortalization. The cells retained their normal karyotype. The activity of ribosomal genes remained unchanged: the degree of their methylation, abundance, and transcriptional activity (two clones were studied). The cells did not undergo significant changes after transition over the Hayflick's limit, retained the constant rate of proliferation (one of the clones was followed to the level of 200 duplications of the population), and resembled, in appearance, young diploid human fibroblasts. The initial cells and cells transfected by an empty vector could pass through no more than 68 duplications, their proliferation slowed down and they acquired the morphology characteristic for the ageing cells. The telomerized cells retained the normal capacity of entering the proliferative rest as a result of serum starvation. Telomerization did not eliminate the contact inhibition of proliferation but led to an increased saturating density of cells, which reached the levels characteristic for the early embryonic cells. The long-term suppression of the telomerase function by azidothymidine led to a shortening of telomeres and significantly slowed down cell proliferation. The cells that did not divided for a long time were enlarged, preserved their viability, and resembled, in appearance, the ageing cells. In the test on heterokaryons (index of telomerase activity on the chromosomes inside the cell), the telomerized cells behaved as other immortal cells. All these data suggest that the telomerized cells preserved the normal mechanisms of regulation of cell proliferation.