SMALL NON-CODING RNA: BIOLOGICAL FUNCTIONS AND BIOMEDICAL APPLICATION

Abstract

Small non-coding RNAs (sncRNA) are short RNA molecules that are involved in gene expression, posttranscriptional modifications and cell immunity regulation. The most studied and the most interesting for the medical application classes are small interfering RNA (siRNA), microRNA (miRNA) and piwi-interacting RNA (piRNA). SncRNAs have a wide range of functions. Primary function of siRNA and miRNA is silencing of gene expression by binding or/and degradation of messenger RNA. PiRNA also have this function but its principal function is control of genome stability on the basis of blocking the activity of transposons. Many diseases, such as cancer, diabetes, neurological, and cardiovascular diseases are accompanied by distortion of sncRNA expression. Abnormal sncRNA expression profile can be used as a hallmark to determine certain type of cancer. In all types of cancer were discovered deviations in the sncRNA pool. From the medical point of view sncRNA can be used as disease marker or as a component of gene therapeutic drugs. In the case of markers usage sncRNAs deserve attention as universal and relatively stable samples. But frequently sncRNAs differ just by few nucleotides, which can create difficulties in their distinguishing. In the frame of gene therapy sncRNAs are able to silence theoretically any gene expression. As sncRNA affects mRNA but not DNA it allows avoiding accidental changes in the genome. In this case delivery systems for RNAs are highly needed, because sncRNAs are unable to penetrate the cell membrane and can be degraded by blood enzymes. Despite of existing problems, sncRNAs are promising compounds for the diagnosis and therapy of wide range of diseases.