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Qi XY, Huang H, Ordog B, Luo X, Naud P, Sun Y, Wu CT, Dawson K, Tadevosyan A, Chen Y, Harada M, Dobrev D, Nattel S. Fibroblast Inward-Rectifier Potassium Current Upregulation in Profibrillatory Atrial Remodeling. Circ Res 2015; 116:836-45. [DOI: 10.1161/circresaha.116.305326] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Rationale:
Fibroblasts are involved in cardiac arrhythmogenesis and contribute to the atrial fibrillation substrate in congestive heart failure (CHF) by generating tissue fibrosis. Fibroblasts display robust ion currents, but their functional importance is poorly understood.
Objective:
To characterize atrial fibroblast inward-rectifier K
+
current (
I
K1
) remodeling in CHF and its effects on fibroblast properties.
Methods and Results:
Freshly isolated left atrial fibroblasts were obtained from controls and dogs with CHF (ventricular tachypacing). Patch clamp was used to record resting membrane potential (RMP) and
I
K1
. RMP was significantly increased by CHF (from −43.2±0.8 mV, control, to −55.5±0.9 mV). CHF upregulated
I
K1
(eg, at −90 mV from −1.1±0.2 to −2.7±0.5 pA/pF) and increased the expression of KCNJ2 mRNA (by 52%) and protein (by 80%). Ba
2+
(300 μmol/L) decreased the RMP and suppressed the RMP difference between controls and dogs with CHF. Store-operated Ca
2+
entry (Fura-2-acetoxymethyl ester) and fibroblast proliferation (flow cytometry) were enhanced by CHF. Lentivirus-mediated overexpression of KCNJ2 enhanced
I
K1
and hyperpolarized fibroblasts. Functional KCNJ2 suppression by lentivirus-mediated expression of a dominant negative KCNJ2 construct suppressed
I
K1
and depolarized RMP. Overexpression of KCNJ2 increased Ca
2+
entry and fibroblast proliferation, whereas the dominant negative KCNJ2 construct had opposite effects. Fibroblast hyperpolarization to mimic CHF effects on RMP enhanced the Ca
2+
entry. MicroRNA-26a, which targets KCNJ2, was downregulated in CHF fibroblasts. Knockdown of endogenous microRNA-26 to mimic CHF effects unregulated
I
K1
.
Conclusions:
CHF upregulates fibroblast KCNJ2 expression and currents, thereby hyperpolarizing RMP, increasing Ca
2+
entry, and enhancing atrial fibroblast proliferation. These effects are likely mediated by microRNA-26a downregulation. Remodeling-induced fibroblast KCNJ2 expression changes may play a role in atrial fibrillation promoting fibroblast remodeling and structural/arrhythmic consequences.
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Affiliation(s)
- Xiao-Yan Qi
- From the Research Center and Department of Medicine, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (X.-Y.Q., H.H., B.O., X.L., P.N., Y.S., C.-T.W., K.D., A.T., Y.C., M.H., S.N.); Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada (K.D., Y.C.); Department of Cardiology, Chang-Gung Memorial Hospital and University, Taoyuan, Taiwan, Republic of China (C.T.W., S.N.); Department of Cardiology, Fujita Health University School of Medicine,
| | - Hai Huang
- From the Research Center and Department of Medicine, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (X.-Y.Q., H.H., B.O., X.L., P.N., Y.S., C.-T.W., K.D., A.T., Y.C., M.H., S.N.); Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada (K.D., Y.C.); Department of Cardiology, Chang-Gung Memorial Hospital and University, Taoyuan, Taiwan, Republic of China (C.T.W., S.N.); Department of Cardiology, Fujita Health University School of Medicine,
| | - Balazs Ordog
- From the Research Center and Department of Medicine, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (X.-Y.Q., H.H., B.O., X.L., P.N., Y.S., C.-T.W., K.D., A.T., Y.C., M.H., S.N.); Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada (K.D., Y.C.); Department of Cardiology, Chang-Gung Memorial Hospital and University, Taoyuan, Taiwan, Republic of China (C.T.W., S.N.); Department of Cardiology, Fujita Health University School of Medicine,
| | - Xiaobin Luo
- From the Research Center and Department of Medicine, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (X.-Y.Q., H.H., B.O., X.L., P.N., Y.S., C.-T.W., K.D., A.T., Y.C., M.H., S.N.); Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada (K.D., Y.C.); Department of Cardiology, Chang-Gung Memorial Hospital and University, Taoyuan, Taiwan, Republic of China (C.T.W., S.N.); Department of Cardiology, Fujita Health University School of Medicine,
| | - Patrice Naud
- From the Research Center and Department of Medicine, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (X.-Y.Q., H.H., B.O., X.L., P.N., Y.S., C.-T.W., K.D., A.T., Y.C., M.H., S.N.); Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada (K.D., Y.C.); Department of Cardiology, Chang-Gung Memorial Hospital and University, Taoyuan, Taiwan, Republic of China (C.T.W., S.N.); Department of Cardiology, Fujita Health University School of Medicine,
| | - Yiguo Sun
- From the Research Center and Department of Medicine, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (X.-Y.Q., H.H., B.O., X.L., P.N., Y.S., C.-T.W., K.D., A.T., Y.C., M.H., S.N.); Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada (K.D., Y.C.); Department of Cardiology, Chang-Gung Memorial Hospital and University, Taoyuan, Taiwan, Republic of China (C.T.W., S.N.); Department of Cardiology, Fujita Health University School of Medicine,
| | - Chia-Tung Wu
- From the Research Center and Department of Medicine, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (X.-Y.Q., H.H., B.O., X.L., P.N., Y.S., C.-T.W., K.D., A.T., Y.C., M.H., S.N.); Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada (K.D., Y.C.); Department of Cardiology, Chang-Gung Memorial Hospital and University, Taoyuan, Taiwan, Republic of China (C.T.W., S.N.); Department of Cardiology, Fujita Health University School of Medicine,
| | - Kristin Dawson
- From the Research Center and Department of Medicine, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (X.-Y.Q., H.H., B.O., X.L., P.N., Y.S., C.-T.W., K.D., A.T., Y.C., M.H., S.N.); Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada (K.D., Y.C.); Department of Cardiology, Chang-Gung Memorial Hospital and University, Taoyuan, Taiwan, Republic of China (C.T.W., S.N.); Department of Cardiology, Fujita Health University School of Medicine,
| | - Artavazd Tadevosyan
- From the Research Center and Department of Medicine, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (X.-Y.Q., H.H., B.O., X.L., P.N., Y.S., C.-T.W., K.D., A.T., Y.C., M.H., S.N.); Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada (K.D., Y.C.); Department of Cardiology, Chang-Gung Memorial Hospital and University, Taoyuan, Taiwan, Republic of China (C.T.W., S.N.); Department of Cardiology, Fujita Health University School of Medicine,
| | - Yu Chen
- From the Research Center and Department of Medicine, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (X.-Y.Q., H.H., B.O., X.L., P.N., Y.S., C.-T.W., K.D., A.T., Y.C., M.H., S.N.); Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada (K.D., Y.C.); Department of Cardiology, Chang-Gung Memorial Hospital and University, Taoyuan, Taiwan, Republic of China (C.T.W., S.N.); Department of Cardiology, Fujita Health University School of Medicine,
| | - Masahide Harada
- From the Research Center and Department of Medicine, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (X.-Y.Q., H.H., B.O., X.L., P.N., Y.S., C.-T.W., K.D., A.T., Y.C., M.H., S.N.); Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada (K.D., Y.C.); Department of Cardiology, Chang-Gung Memorial Hospital and University, Taoyuan, Taiwan, Republic of China (C.T.W., S.N.); Department of Cardiology, Fujita Health University School of Medicine,
| | - Dobromir Dobrev
- From the Research Center and Department of Medicine, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (X.-Y.Q., H.H., B.O., X.L., P.N., Y.S., C.-T.W., K.D., A.T., Y.C., M.H., S.N.); Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada (K.D., Y.C.); Department of Cardiology, Chang-Gung Memorial Hospital and University, Taoyuan, Taiwan, Republic of China (C.T.W., S.N.); Department of Cardiology, Fujita Health University School of Medicine,
| | - Stanley Nattel
- From the Research Center and Department of Medicine, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (X.-Y.Q., H.H., B.O., X.L., P.N., Y.S., C.-T.W., K.D., A.T., Y.C., M.H., S.N.); Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada (K.D., Y.C.); Department of Cardiology, Chang-Gung Memorial Hospital and University, Taoyuan, Taiwan, Republic of China (C.T.W., S.N.); Department of Cardiology, Fujita Health University School of Medicine,
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