MICRORNAS AS ULTRAVIOLET IRRADIATION EFFECTS REGULATORS IN SKIN CELLS.

MicroRNAs belong to small non-coding RNA which regulate gene expression via mRNA degradation or translation inhibition. MicroRNAs are active modulators of gene expression in the skin caused by exogenous factors including ultraviolet irradiation. These effects are realized by targeting transcription factors and signaling systems components. Changes in microRNAs levels started to register in a few hours after exposure to ultraviolet irradiation, wich confirms the presence of an effective fast processes in the scin cells that modulate the functional status of microRNAs. The reported recently ability of microRNAs to be transported by exosomes may be related to systemic effects of ultraviolet irradiation that include the altered immune response and systemic inflammatory reaction. Understanding these processes is important because of the possibility of purposeful influence on the expression and activity of a microRNA that may have implications for diagnosis and therapy of photodermatosis and malignant skin tumors.

[The influence of diets on metabolic processes associated with sirtuin1].

Over the last decade the investigations of the sirtuin protein family have become one of the research priorities. It is connected with the fact that sirtuins play an important role as regulators of cell homeostasis in mammals. Sirtuins can regulate metabolism by the influence on some processes in CNS, liver, pancreas, musles, adipose tissue. It emphasizes the importance of sirtuins in the development of heart diseases, cancer, metabolic syndrome, neurodegenerative and some other diseases. Stress factors in particular calorie restriction alter sirtuins activity, that leads to some significant alterations of intracellular processes: activation of reparation processes, increase of DNA stability, elevation of metabolic rate and the lifespan of cells. In this review, we focus our attention on the influence of calorie restriction on metabolic alterations associated with regulatory role of sirtuin1. Sirtuin1 plays a leading role in regulation of cell homeostasis by controlling some important processes, such as gene transcription, cell differentiation, stress reaction, inflammation, apoptosis, circadian rhythms and life expectancy. We touch briefly on the connection between some alterations of diet and the development of stress reaction and inflammation. In the review the metabolic alterations in liver, pancreas, adipose tissue and central regulatory role of sirtuinl in hypothalamic-pituitary-adrenal axis connected with calorie restriction are discussed. Sirtuin1 can be a messenger of some effects of calorie restriction on organism, acting as a cell energy sensor. Thus, sirtuinl plays a central role in control and modulation of metabolic processes under alterations of diet. Having been one of the most important regulator of homeostasis, sirtuinl can be a key element of regulation. The influence on this element gives the opportunities of regulation of metabolism, calorie restriction effects and creation of new pathogenical methods of treatment.