Changes in Electrophysiological Features of Rats’ Working Atrial Myocardium after Its Lipotransfection with MicroRNAs miR-1-3p, miR-153-3p, or miR-133a-3p

Abstract

MicroRNA is a small, single-stranded nucleotide sequence, which can regulate gene expression at the posttranscriptional level. To date, it is known that some microRNAs play an important role in physiology and pathophysiology of the cardio-vascular system. The effects of lipotransfection with microRNAs, such as miR-1-3p, miR-153-3p, or miR-133-3p, on the electrophysiological indices of the myocardium tissue were studied here for the first time. With the use of the standard microelectrode technique, action potentials (AP) in isolated perfused samples of the rat atrial tissue were recorded after their treatment with a transfection mixture of a liposome forming reagent and miR-1-3p, miR-153-3p, or miR-133-3p. It is demonstrated that the treatment of the myocardial tissue with a transfection agent results in the prolongation of the repolarization phase of AP. It was found that miR-1-3p and miR-153-3p did not affect the pattern of AP within 6 h after the treatment of tissue samples. However, miR133a-3p evoked a statistically significant increase in the AP duration under 90% repolarization. The duration was maximum 4 h after the transfection. Search and analysis of possible targets for miR133a-3p using bioinformatic methods were performed and it was assumed that this microRNA can interact with mRNA of some protein phosphatases. Suppression of protein phosphatases’ expression in cardiomyocytes may underlie the increased AP duration during the application of miR133a-3p found in the present study due to the effect on the proteins of calcium turnover.