Malé molekuly RNA a jejich význam v imunitní odpovědi organismu.

Micro RNAs (miRNAs) are a group of short, approximately 22nt long, single-stranded, endogenous and evolutionarily conserved non-coding RNAs. These molecules postranscriptionally regulate the expression of structural genes. By a mechanism termed RNA interference (RNAi) they modulate stability and translational efficiency of target messenger RNAs and thus the intracellular protein levels.MiRNAs can be found in various species, they make up 1-2% of eukaryotic genomes, and regulate expression of about one-third of protein-coding genes. MiRNAs participate in regulation of key biological processes (cell growth, differentiation, proliferation, and apoptosis). Recent findings highlight the crucial importance of miRNAs in development, homeostasis and function of innate and adaptive immunity. Deregulation of miRNA expression is involved in pathogenesis of malignancies, heart diseases, neurodegenerative and inflammatory autoimmune disorders and infections. In systemic autoimmune diseases, miRNAs play a key role in the regulation of major pathogenic molecules (TNFα), central signaling pathways (IFN type I) and critical immunoregulatory cells (regulatory T cells). MiRNA molecules have a considerable potential as a new class of therapeutic targets and diagnostic biomarkers. This article gives a brief overview of miRNA molecules, their role in the immune response and their relation to systemic autoimmune diseases. [ABSTRACT FROM AUTHOR]