The Effect Of MiR-103a-3p On Ikr Encoded By HERC Gene

Background and Objective : Long QT Syndrome(LQTS)is clinically characterized by sudden onset of syncope,ventricular tachycardia or sudden death,while electrocardiogram can detect QT interval prolongation and T wave abnormalities.In clinical work,aLQTS is more common and dangerous.It is closely related to the pathogenesis of TdP and is potentially fatal.It is one of the important causes of sudden cardiac death in hospital.Studies have shown that the rapid activation of activating component of delayed rectifier potassium current(IKr)encoded by hERG(huarm ether-a-Go-Go related gene,hERG)plays a key role in the normal action potential repolarization process.,most closely related to QT interval extension and Tdp.In the early stage,the bioinformatics comparison was used to screen out hERG-related miRNAs,and in the HEK-293 cells,cardiomyocytes H9C2 and neonatal rat cardiomyocytes,miRNA was verified by Western Blot,PCR and laser confocal experiments.miRNA-103a-1 down-regulates the expression of the hERG gene,thereby affecting the Ikr current.This experiment aims to verify the correlation between miR-103 a and IKr in cardiomyocytes at the electrophysiological level,and further explore the relationship between the two,providing a new entry point for drug treatment of long QT syndrome.Materials and Methods: Cultured cardiomyocytes H9c2.The miR-103a-3p agomir,miR-103a-3p agomir NC,miR-103a-3p antagomir,miR-103a-3p antagomir NC were divided into four groups by transient transfection technique,and H9C2 was transfected in each culture dish.Wait24~48 hours of transfection,whole cell patch clamp technique was used to detect the magnitude of Ikr current in each group of cells.Results :(1)After rno-miR-103-3p agomir NC and rno-miR-103-3p agomir were transfected into H9C2,the whole-cell patch clamp technique detected Ikr current amplitudes of31.42±2.763 pA and 12.94±0.6864 pA,respectively.The current amplitude is reduced by 58.8%(n=6,p<0.05);(2)After rno-miR-103-3p atagomir NC and rno-miR-103-3p atagomir were transfected into H9C2,the whole-cell patch clamp technique detected Ikr current amplitudes of55.48±3.143 pA and 94.11±3.279 pA,respectively.Current amplitude increased by 69.6%(n=6,p<0.05)。Conclusion: The results of this experiment lead to the following conclusions:(1)hERG gene is the target gene of miR-103a-3p;(2)miR-103a-3p can attenuate the Ikr current of hERG gene,while AMO-103a-3p can silence This effect of miR-103a-3p.Therefore,the results of this experiment can better clarify the electrophysiological pathway of miRNA-103a-3p targeting hERGand regulating Ikr current,thus providing some ideas for drug therapy and gene therapy of aLQTs.These experimental conclusions need to be further validated in animal models or animal cells as well as in clinical studies.