title: Effect of small interference RNA on the acetylcholine-sensitive potassium channel in H9c2 cells.
abstract: BACKGROUND
  The acetylcholine-sensitive potassium channel (IK(ACh)) expresses only in the atrium, not in the ventricle. The main component of the rat IK(ACh) channel is the Kir3.4 protein, and its encoding gene is the KCNJ5 gene. IK(ACh) inhibitors provide a promising treatment for atrial fibrillation without side effects on the ventricle. At present, however, there is no specific IK(ACh) inhibitor. Small interference RNA (siRNA) has the advantages of high specificity and high efficiency. Our aim is to use siRNA to inhibit the IK(ACh) channel on H9c2 cells derived from rat cardiomyocytes.
  
  
  METHODS
  Three pairs of siRNAs targeting the rat IK(ACh) channel were synthesized. H9c2 cells were divided into six groups: control, negative siRNA control, siRNA sequence 1, siRNA sequence 2, siRNA sequence 3, and amiodarone. The KCNJ5 gene and Kir3.4 protein were measured, and IK(ACh) currents were recorded by patch-clamp.
  
  
  RESULTS
  The negative siRNA control and siRNA sequence 1 had no inhibitory effects on the IK(ACh) channel. siRNA sequences 2 and 3 could cause a significant decrease in KCNJ5 gene expression, Kir3.4 protein, and IK(ACh) currents (p<0.05). Amiodarone could inhibit the IK(ACh) currents but had no effect on KCNJ5 gene expression and Kir3.4 protein.
  
  
  CONCLUSIONS
  siRNA could effectively inhibit the IK(ACh) channel and is a potential therapy for atrial fibrillation.
authors.affiliation: Department of Cardiology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province.
authors.forename: Fei
authors.initials: F
authors.lastname: He
authors.affiliation: Department of Cardiology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of Cardiology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province.
authors.forename: Ling
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Hematology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province, China hefeihn71@sina.com.
authors.forename: Rong
authors.initials: R
authors.lastname: Guo
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels / Q000378:metabolism*; D015640:Ion Channel Gating; D024661:Potassium Channels, Inwardly Rectifying / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000378:metabolism*; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D014162:Transfection
chemical_list: D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; C092387:Kcnj5 protein, rat; D024661:Potassium Channels, Inwardly Rectifying; D034741:RNA, Small Interfering; D000109:Acetylcholine
keywords: acetylcholine-sensitive potassium channel; atrial fibrillation; patch clamp; small interference RNA