Potential application of microRNA in disease diagnostics and treatment

miRNA su kratke (18-28 nukleotida), evolucijski visokoočuvane, nekodirajuće RNA molekule koje imaju specifičnu ulogu u regulaciji genske ekspresije. Geni za miRNA se nalaze na kromosomima u jezgri, i na temelju smještaja u genomu dijele se na intergenske i intragenske. Smatra se da je oko 30% protein-kodirajućih gena regulirano pomoću miRNA. Zrela miRNA nastaje djelovanjem brojnih enzima kroz nekoliko koraka, a djeluje u kompleksu koji se naziva miRISC. miRNA se veže na temelju komplementarnosti slijeda „seed“ na 3'-UTR ciljne mRNA, što dovodi do inhibicije translacije ili razgradnje mRNA. Razvijene su brojne metode za izolaciju, detekciju i kvantifikaciju miRNA. Ekspresija miRNA je vrlo precizno regulirana i dinamična u prostoru i vremenu. AntimiRNA i miRNA mimetici su terapeutici temeljeni na miRNA kojima je cilj redukcija ili zamjena miRNA. Cirkulirajuće miRNA su miRNA koje se nalaze u tjelesnim tekućinama i zbog svoje izvanredne stabilnosti mogu se koristiti kao biomarkeri u dijagnostici i prognostici. Promijenjena ekspresija miRNA prisutna je kod svih vrsta tumora. Čimbenici okoliša kojima je plod izložen tijekom unutarmateričnog razvoja uzrokuju promjene u ekspresijskim profilima miRNA koje mogu rezultirati različitim zdravstvenim ishodima kasnije u životu.miRNAs are small (18-28 nt), highly conserved, non-coding RNAs which play specific role in the regulation of gene expression. miRNA genes are located on chromosomes in nucleus, and on the basis of genomic arrangement, they can be classified as intergenic and intragenic. It is estimated that about 30% of protein-coding genes are miRNA-controlled. Mature miRNA is generated by the action of many enzymes through several steps, and acts in complex named miRISC. miRNA binds by its seed sequence to the complementary 3'-UTR of its target mRNA, which results in mRNA degradation or inhibition of translation. Many methods for miRNA isolation, detection and quantification are developed. miRNA expression is highly regulated and dynamic process. AntimiRNAs and miRNAs mimics are sintetic therapeutics based on miRNA with aim to reduce or replace miRNA, respectively. Circulating miRNAs are miRNAs with remarkable stability, which are located in body fluids and can be used as biomarkers for diagnostic and prognostic purposes. Aberrant expressions of miRNAs have been found in all types of tumors. Environmental factors which influence fetus during in-utero development induce changes in miRNA expression profiles which can lead to different health outcomes that manifest later in life