Molecular Mechanisms Underlying Urate-Induced Enhancement of Kv1.5 Channel Expression in HL-1 Atrial Myocytes

Nani Maharani; Ya Kuang Ting; Jidong Cheng; Akira Hasegawa; Yasutaka Kurata; Peili Li; Yuji Nakayama; Haruaki Ninomiya; Nobuhito Ikeda; Kumi Morikawa; Kazuhiro Yamamoto; Naomasa Makita; Takeshi Yamashita; Yasuaki Shirayoshi; Ichiro Hisatome

doi:10.1253/circj.CJ-15-0416

Molecular Cardiology

Molecular Mechanisms Underlying Urate-Induced Enhancement of Kv1.5 Channel Expression in HL-1 Atrial Myocytes

Nani Maharani, Ya Kuang Ting, Jidong Cheng, Akira Hasegawa, Yasutaka Kurata, Peili Li, Yuji Nakayama, Haruaki Ninomiya, Nobuhito Ikeda, Kumi Morikawa, Kazuhiro Yamamoto, Naomasa Makita, Takeshi Yamashita, Yasuaki Shirayoshi, Ichiro Hisatome

Author information

Nani Maharani
Division of Regenerative Medicine and Therapeutics, Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science
Department of Pharmacology and Therapeutics, Faculty of Medicine Diponegoro University
Ya Kuang Ting
Division of Regenerative Medicine and Therapeutics, Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science
Jidong Cheng
Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College
Akira Hasegawa
Division of Regenerative Medicine and Therapeutics, Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science
Yasutaka Kurata
Department of Physiology, Kanazawa Medical University
Peili Li
Division of Regenerative Medicine and Therapeutics, Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science
Yuji Nakayama
Division of Functional Genomics, Research Center for Bioscience and Technology, Tottori University Faculty of Medicine
Haruaki Ninomiya
Department of Biological Regulation, Tottori University Faculty of Medicine
Nobuhito Ikeda
Division of Regenerative Medicine and Therapeutics, Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science
Kumi Morikawa
Division of Regenerative Medicine and Therapeutics, Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science
Kazuhiro Yamamoto
Department of Molecular Medicine and Therapeutics, Tottori University Faculty of Medicine
Naomasa Makita
Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Science
Takeshi Yamashita
The Cardiovascular Institute
Yasuaki Shirayoshi
Division of Regenerative Medicine and Therapeutics, Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science
Ichiro Hisatome
Division of Regenerative Medicine and Therapeutics, Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science

Keywords: Atrial fibrillation, ERK, Kv1.5, Oxidative stress, Urate

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Supplementary material

2015 Volume 79 Issue 12 Pages 2659-2668

DOI https://doi.org/10.1253/circj.CJ-15-0416

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Abstract

Background:Hyperuricemia induces endothelial dysfunction, oxidative stress and inflammation, increasing cardiovascular morbidities. It also raises the incidence of atrial fibrillation; however, underlying mechanisms are unknown.Methods and Results:The effects of urate on expression of Kv1.5 in cultured mouse atrial myocytes (HL-1 cells) using reverse transcriptase-PCR, immunoblots, flow cytometry and patch-clamp experiments were studied. Treatment with urate at 7 mg/dl for 24 h increased the Kv1.5 protein level, enhanced ultra-rapid delayed-rectifier K⁺channel currents and shortened action potential duration in HL-1 cells. HL-1 cells expressed the influx uric acid transporter (UAT), URATv1, and the efflux UATs, ABCG2 and MRP4. An inhibitor against URATv1, benzbromarone, abolished the urate effects, whereas an inhibitor against ABCG2, KO143, augmented them. Flow cytometry showed that urate induced an increase in reactive oxygen species, which was abolished by the antioxidant, N-acetylcysteine (NAC), and the NADPH-oxidase inhibitor, apocynin. Both NAC and apocynin abolished the enhancing effects of urate on Kv1.5 expression. A urate-induced increase in the Kv1.5 proteins was accompanied by phosphorylation of extracellular signal-regulated kinase (ERK), and was abolished by an ERK inhibitor, PD98059. NAC abolished phosphorylation of ERK by urate.Conclusions:Intracellular urate taken up by UATs enhanced Kv1.5 protein expression and function in HL-1 atrial myocytes, which could be attributable to ERK phosphorylation and oxidative stress derived from nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase. (Circ J 2015; 79: 2659–2668)

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