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Zhang HQ, Lin JL, Pan L, Mao L, Pang JL, Yuan Q, Li GY, Yi GS, Lin YB, Feng BL, Li YD, Wang Y, Jie LJ, Zhang YH. Enzastaurin cardiotoxicity: QT interval prolongation, negative inotropic responses and negative chronotropic action. Biochem Pharmacol 2023; 209:115443. [PMID: 36720353 DOI: 10.1016/j.bcp.2023.115443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 01/22/2023] [Accepted: 01/23/2023] [Indexed: 01/31/2023]
Abstract
Several clinical trials observed that enzastaurin prolonged QT interval in cancer patients. However, the mechanism of enzastaurin-induced QT interval prolongation is unclear. Therefore, this study aimed to assess the effect and mechanism of enzastaurin on QT interval and cardiac function. The Langendorff and Ion-Optix MyoCam systems were used to assess the effects of enzastaurin on QT interval, cardiac systolic function and intracellular Ca2+ transient in guinea pig hearts and ventricular myocytes. The effects of enzastaurin on the rapid delayed rectifier (IKr), the slow delayed rectifier K+ current (IKs), transient outward potassium current (Ito), action potentials, Ryanodine Receptor 2 (RyR2) and the sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2a (SERCA2a) expression and activity in HEK 293 cell system and primary cardiomyocytes were investigated using whole-cell recording technique and western blotting. We found that enzastaurin significantly prolonged QT interval in guinea pig hearts and increased the action potential duration (APD) in guinea pig cardiomyocytes in a dose-dependent manner. Enzastaurin potently inhibited IKr by binding to the human Ether-à-go-go-Related gene (hERG) channel in both open and closed states, and hERG mutant channels, including S636A, S631A, and F656V attenuated the inhibitory effect of enzastaurin. Enzastaurin also moderately decreased IKs. Additionally, enzastaurin also induced negative chronotropic action. Moreover, enzastaurin impaired cardiac systolic function and reduced intracellular Ca2+ transient via inhibition of RyR2 phosphorylation. Taken together, we found that enzastaurin prolongs QT, reduces heart rate and impairs cardiac systolic function. Therefore, we recommend that electrocardiogram (ECG) and cardiac function should be continuously monitored when enzastaurin is administered to cancer patients.
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Affiliation(s)
- He-Qiang Zhang
- Institute of Cardiovascular Diseases, Xiamen Cardiovascular Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Jia-le Lin
- Institute of Cardiovascular Diseases, Xiamen Cardiovascular Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Lei Pan
- Institute of Cardiovascular Diseases, Xiamen Cardiovascular Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Liang Mao
- Institute of Cardiovascular Diseases, Xiamen Cardiovascular Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China; Key Laboratory of Medical Electrophysiology, Southwest Medical University, Luzhou, Sichuan, China
| | - Jing-Long Pang
- Institute of Cardiovascular Diseases, Xiamen Cardiovascular Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Qian Yuan
- Institute of Cardiovascular Diseases, Xiamen Cardiovascular Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Gui-Yang Li
- Department of Cardiology, Xiamen Cardiovascular Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Gang-Si Yi
- Institute of Cardiovascular Diseases, Xiamen Cardiovascular Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Yang-Bin Lin
- Institute of Cardiovascular Diseases, Xiamen Cardiovascular Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Bao-Long Feng
- Institute of Cardiovascular Diseases, Xiamen Cardiovascular Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Yun-da Li
- Institute of Cardiovascular Diseases, Xiamen Cardiovascular Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Yan Wang
- Department of Cardiology, Xiamen Cardiovascular Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China.
| | - Ling-Jun Jie
- Institute of Cardiovascular Diseases, Xiamen Cardiovascular Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China; Department of Cardiology, Xiamen Cardiovascular Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China.
| | - Yan-Hui Zhang
- Institute of Cardiovascular Diseases, Xiamen Cardiovascular Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China.
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Foti F, De-Giorgio F, Vetrugno G, Basso C, Pilichou K. A de novo ryanodine receptor 2 gene variant in a case of sudden cardiac death. Int J Legal Med 2020; 134:619-23. [PMID: 31605164 DOI: 10.1007/s00414-019-02160-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 09/05/2019] [Indexed: 12/14/2022]
Abstract
A 34-year-old man, who was previously fit and healthy, died suddenly on exercise. A post-mortem exam performed by forensic pathologists and a toxicological screening were normal; therefore, the cause of death was suspected to be sudden arrhythmic death syndrome, prompting the need for a molecular autopsy. Screening for genetic variations underlying arrhythmogenic genes by next-generation sequencing highlighted a heterozygous single-nucleotide variant in the exon n. 94 of the ryanodine receptor type 2 gene. This gene, encoding the cardiac ryanodine receptor, is one of the main genetic variants of catecholaminergic polymorphic ventricular tachycardia, estimated to affect 1 in 10,000 individuals. It manifests with syncope, seizures, or sudden death due to exercise- or emotional stress-induced bidirectional or polymorphic ventricular tachycardia, usually in children and young adults with morphologically normal hearts and normal baseline electrocardiograms. Even if this de novo missense mutation has not yet been associated with catecholaminergic polymorphic ventricular tachycardia, it is likely to be a disease-causing variant which leads to a defective protein responsible for disturbed ion flow.
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Mahlke N, Dittmann S, Schulze-Bahr E, Ritz-Timme S, Hartung B. Sudden unexpected cardiac death and postmortem identification of a novel RYR2 gene mutation. Int J Legal Med 2019; 133:1835-8. [PMID: 31289932 DOI: 10.1007/s00414-019-02117-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 06/25/2019] [Indexed: 12/11/2022]
Abstract
A 13-year-old female was found lifeless at home. The autopsy and consecutive histological and toxicological examinations showed blood-rich and edematous lungs and foamy bloody content in the airways. No morphologic pathological findings were seen, especially no bleeding sources. Toxicological findings were unremarkable. The specific cause of death remained unclear. Due to reported losses of consciousness, a moleculargenetic postmortem testing was performed. A so far undescribed mutation in the cardiac ryanodine receptor gene RyR2 was detected. This mutation is suitable to explain the case history as well as the morphological findings. The cardiac ryanodine receptor gene RyR2 encodes the ryanodine receptor type 2, an ion channel in the cardiomyocytes. The ion channel regulates the influx of calcium ions and thus influences myocardial activity. Mutations in this channel may result in the catecholaminergic polymorphic ventricular tachycardia (CPVT), a cardiac arrhythmia that can lead to syncope and sudden cardiac death. This case demonstrates the usefulness and need of molecular autopsy, in particular to identify and treat possibly affected family members.
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Okuda S, Sufu-Shimizu Y, Kato T, Fukuda M, Nishimura S, Oda T, Kobayashi S, Yamamoto T, Morimoto S, Yano M. CaMKII-mediated phosphorylation of RyR2 plays a crucial role in aberrant Ca 2+ release as an arrhythmogenic substrate in cardiac troponin T-related familial hypertrophic cardiomyopathy. Biochem Biophys Res Commun 2018; 496:1250-1256. [PMID: 29402414 DOI: 10.1016/j.bbrc.2018.01.181] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 01/30/2018] [Indexed: 02/05/2023]
Abstract
AIMS Cardiac Troponin T (TnT) mutation-linked familial hypertrophic cardiomyopathy (FHC) is known to cause sudden cardiac death at a young age. Here, we investigated the role of the Ca2+ release channel of the cardiac sarcoplasmic reticulum (SR), ryanodine receptor (RyR2), in the pathogenic mechanism of lethal arrhythmia in FHC-related TnT-mutated transgenic mice (TG; TnT-delta160E). METHODS AND RESULTS In TG cardiomyocytes, the Ca2+ spark frequency (SpF) was much higher than that in non-TG cardiomyocytes. These differences were more pronounced in the presence of isoproterenol (ISO; 10 nM). This increase in SpF was largely reversed by a CaMKII inhibitor (KN-93), but not by a protein kinase A inhibitor (H89). CaMKII phosphorylation at Ser2814 in RyR2 was increased significantly in TG. Spontaneous Ca2+ transients (sCaTs) after cessation of a 1-5 Hz pacing, frequently observed in ISO-treated TG cardiomyocytes, were also attenuated by KN-93, but not by H89. The RyR2 stabilizer dantrolene attenuated Ca2+ sparks and sCaTs in ISO-treated TG cardiomyocytes, indicating that the mutation-linked aberrant Ca2+ release is mediated by destabilized RyR2. CONCLUSIONS In FHC-linked TnT-mutated hearts, RyR2 is susceptible to CaMKII-mediated phosphorylation, presumably because of a mutation-linked increase in diastolic [Ca2+]i, causing aberrant Ca2+ release leading to lethal arrhythmia.
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Affiliation(s)
- Shinichi Okuda
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan.
| | - Yoko Sufu-Shimizu
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan
| | - Takayoshi Kato
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan
| | - Masakazu Fukuda
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan
| | - Shigehiko Nishimura
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan
| | - Tetsuro Oda
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan
| | - Shigeki Kobayashi
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan
| | - Takeshi Yamamoto
- Department of Clinical Laboratory Science, Faculty of Health Sciences, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan
| | - Sachio Morimoto
- Department of Health Sciences Fukuoka, International University of Health and Welfare, 131-7 Enokizu, Okawa, Fukuoka 831-8501, Japan
| | - Masafumi Yano
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan
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Wang Q, Wang W, Wang G, Rodney GG, Wehrens XH. Crosstalk between RyR2 oxidation and phosphorylation contributes to cardiac dysfunction in mice with Duchenne muscular dystrophy. J Mol Cell Cardiol 2015; 89:177-84. [PMID: 26555638 DOI: 10.1016/j.yjmcc.2015.11.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 10/28/2015] [Accepted: 11/05/2015] [Indexed: 12/24/2022]
Abstract
BACKGROUND Patients with Duchenne muscular dystrophy (DMD) are at risk of developing cardiomyopathy and cardiac arrhythmias. Studies in a mouse model of DMD revealed that enhanced sarcoplasmic reticulum (SR) Ca(2+) leak contributes to the pathogenesis of cardiac dysfunction. In view of recent data suggesting the involvement of altered phosphorylation and oxidation of the cardiac ryanodine receptor (RyR2)/Ca(2+) release channel, we hypothesized that inhibition of RyR2 phosphorylation in a mouse model of DMD can prevent SR Ca(2+) leak by reducing RyR2 oxidation. METHODS AND RESULTS Confocal Ca(2+) imaging and single RyR2 channel recordings revealed that both inhibition of S2808 or S2814 phosphorylation, and inhibition of oxidation could normalize RyR2 activity in mdx mice. Moreover, Western blotting revealed that genetic inhibition of RyR2 phosphorylation at S2808 or S2814 reduced RyR2 oxidation. Production of reactive oxygen species (ROS) in myocytes from mdx mice was reduced by both inhibition of RyR2 phosphorylation or the ROS scavenger 2-mercaptopropionyl glycine (MPG). Finally, it was shown that ROS production in mdx mice is proportional to the activity of RyR2-mediated SR Ca(2+) leak, and likely generated by Nox2. CONCLUSIONS Increased ROS production in the hearts of mdx mice drives the progression of cardiac dysfunction. Inhibition of RyR2 phosphorylation can suppress SR Ca(2+) leak in mdx mouse hearts in part by reducing RyR2 oxidation.
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Chiang DY, Li N, Wang Q, Alsina KM, Quick AP, Reynolds JO, Wang G, Skapura D, Voigt N, Dobrev D, Wehrens XHT. Impaired local regulation of ryanodine receptor type 2 by protein phosphatase 1 promotes atrial fibrillation. Cardiovasc Res 2014; 103:178-87. [PMID: 24812280 DOI: 10.1093/cvr/cvu123] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
AIMS Altered Ca(2+) handling in atrial fibrillation (AF) has been associated with dysregulated protein phosphatase 1 (PP1) and subcellular heterogeneities in protein phosphorylation, but the underlying mechanisms remain unclear. This is due to a lack of investigation into the local, rather than global, regulation of PP1 on different subcellular targets such as ryanodine receptor type 2 (RyR2), especially in AF. METHODS AND RESULTS We tested the hypothesis that impaired local regulation of PP1 causes RyR2 hyperphosphorylation thereby promoting AF susceptibility. To specifically disrupt PP1's local regulation of RyR2, we used the spinophilin knockout (Sp(-/-)) mice (Mus musculus) since PP1 is targeted to RyR2 via spinophilin. Without spinophilin, the interaction between PP1 and RyR2 was reduced by 64%, while RyR2 phosphorylation was increased by 43% at serine (S)2814 but unchanged at S2808. Lipid bilayer experiments revealed that single RyR2 channels isolated from Sp(-/-) hearts had an increased open probability. Likewise, Ca(2+) spark frequency normalized to sarcoplasmic reticulum Ca(2+) content was also enhanced in Sp(-/-) atrial myocytes, but normalized by Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) inhibitors KN-93 and AIP and also by genetic inhibition of RyR2 S2814 phosphorylation. Finally, Sp(-/-) mice exhibited increased atrial ectopy and susceptibility to pacing-induced AF, both of which were also prevented by the RyR2 S2814A mutation. CONCLUSION PP1 regulates RyR2 locally by counteracting CaMKII phosphorylation of RyR2. Decreased local PP1 regulation of RyR2 contributes to RyR2 hyperactivity and promotes AF susceptibility. This represents a novel mechanism for subcellular modulation of calcium channels and may represent a potential drug target of AF.
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Affiliation(s)
- David Y Chiang
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Na Li
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Qiongling Wang
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Katherina M Alsina
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Ann P Quick
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Julia O Reynolds
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Guoliang Wang
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
| | - Darlene Skapura
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Niels Voigt
- Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - Dobromir Dobrev
- Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA Department of Medicine (Cardiology), Baylor College of Medicine, Houston, TX, USA
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