A DEFINIR
Atrial fibrillation; neonatal cardiomyocytes; miRNA; Anti-miR; mRNA; Mimic-miR; Hl-1.
Atrial Fibrillation (AF) is the most prevalent arrhythmia worldwide. The diagnosis is made by ECG, however the asymptomatology of many patients and the short duration of fibrillation hamper early detection, leading to late diagnoses. Transcriptomic analyzes show that miRNAs regulate mRNA gene expression and are potential targets for the diagnosis, prognosis and treatments of AF. In this perspective, in our previous studies it was possible to demonstrate that miR-133b and miR-328 are significantly expressed in individuals with acute AF, which prompted us to understand some regulatory mechanisms of these miRNAs in AF. Thus, the objective of this study was to investigate the regulatory role of miR-133b and miR-328 in gene expression of mRNA in Atrial Fibrillation using in vitro inhibition and mimic technologies and to reassess the circulating expression of these miRNAs in this disease in vivo. The in vitro study was carried out using a culture of neonatal cardiomyocytes as a model without AF in addition to atrial cardiomyocytes HL-1 as an already established model of AF. Troponin T staining, optical calcium mapping and electrophysiological records with whole-patch clamp were used to characterize HL-1 cells as a model of AF. The anti-miR and mimic-miR techniques of miRNAs were used to observe the regulation of miR-133b and miR-328 in the expression of mRNAs of Mhy6, Myoz2, Pln, Cacna1c, Kcne1 and Scn5a. Previous results demonstrate that Scn5a and Pln can be direct targets for miR-133b. In the in vivo study, we evaluated the circulating expression of miR-133b and miR-328 in plasma of patients with stable AF N = 42, with acute AF N = 4, and control subjects, N = 30, and previous results suggest that there is a tendency towards greater expression of miR-133b and patients with acute AF, compared to stable AF and controls. It is expected that upon completion of all analyzes there will be sufficient data to confirm the activity of miR-133b and miR-328 under the expression of the target mRNAs of this study, seeking to demonstrate some of the regulatory roles of these miRNAs in Atrial Fibrillation.