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Novel preventive effect of isorhamnetin on electrical and structural remodeling in atrial fibrillation. Clin Sci (Lond) 2022; 136:1831-1849. [DOI: 10.1042/cs20220319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 11/22/2022] [Accepted: 12/01/2022] [Indexed: 12/24/2022]
Abstract
Abstract
Isorhamnetin, a natural flavonoid, has strong antioxidant and antifibrotic effects, and a regulatory effect against Ca2+-handling. Atrial remodeling due to fibrosis and abnormal intracellular Ca2+ activities contributes to initiation and persistence of atrial fibrillation (AF). The present study investigated the effect of isorhamnetin on angiotensin II (AngII)-induced AF in mice. Wild-type male mice (C57BL/6J, 8 weeks old) were assigned to three groups: (1) control group, (2) AngII-treated group, and (3) AngII- and isorhamnetin-treated group. AngII (1000 ng/kg/min) and isorhamnetin (5 mg/kg) were administered continuously via an implantable osmotic pump for two weeks and intraperitoneally one week before initiating AngII administration, respectively. AF induction and electrophysiological studies, Ca2+ imaging with isolated atrial myocytes and HL-1 cells, and action potential duration (APD) measurements using atrial tissue and HL-1 cells were performed. AF-related molecule expression was assessed and histopathological examination was performed. Isorhamnetin decreased AF inducibility compared with the AngII group and restored AngII-induced atrial effective refractory period prolongation. Isorhamnetin eliminated abnormal diastolic intracellular Ca2+ activities induced by AngII. Isorhamnetin also abrogated AngII-induced APD prolongation and abnormal Ca2+ loading in HL-1 cells. Furthermore, isorhamnetin strongly attenuated AngII-induced left atrial enlargement and atrial fibrosis. AngII-induced elevated expression of AF-associated molecules, such as ox-CaMKII, p-RyR2, p-JNK, p-ERK, and TRPC3/6, was improved by isorhamnetin treatment. The findings of the present study suggest that isorhamnetin prevents AngII-induced AF vulnerability and arrhythmogenic atrial remodeling, highlighting its therapeutic potential as an anti-arrhythmogenic pharmaceutical or dietary supplement.
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Yang PC, Jafri MS. Ca 2+ signaling in T lymphocytes: the interplay of the endoplasmic reticulum, mitochondria, membrane potential, and CRAC channels on transcription factor activation. Heliyon 2020; 6:e03526. [PMID: 32181396 PMCID: PMC7063158 DOI: 10.1016/j.heliyon.2020.e03526] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 09/12/2018] [Accepted: 02/28/2020] [Indexed: 11/16/2022] Open
Abstract
T cell receptor stimulation initiates a cascade of reactions that cause an increase in intracellular calcium (Ca2+) concentration mediated through inositol 1,4,5-trisphosphate (IP3). To understand the basic mechanisms by which the immune response in T cells is activated, it is useful to understand the signaling pathways that contain important targets for drugs in a quantitative fashion. A computational model helps us to understand how the selected elements in the pathways interact with each other, and which component plays the crucial role in systems. We have developed a mathematical model to explore the mechanism for controlling transcription factor activity, which regulates gene expression, by the modulation of calcium signaling triggered during T cell activation. The model simulates the activation and modulation of Ca2+ release-activated Ca2+ (CRAC) channels by mitochondrial dynamics and depletion of endoplasmic reticulum (ER) store, and also includes membrane potential in T-cells. The model simulates the experimental finding that increases in Ca2+ current enhances the activation of transcription factors and the Ca2+ influx through CRAC is also essential for the NFAT and NFκB activation. The model also suggests that plasma membrane Ca2+-ATPase (PMCA) controls a majority of the extrusion of Ca2+ and modulates the activation of CRAC channels. Furthermore, the model simulations explain how the complex interaction of the endoplasmic reticulum, membrane potential, mitochondria, and ion channels such as CRAC channels control T cell activation.
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Affiliation(s)
- Pei-Chi Yang
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA, 95616, USA.,Krasnow Institute for Advanced Study and School of Systems Biology, George Mason University, Fairfax, VA, 22030, USA
| | - M Saleet Jafri
- Krasnow Institute for Advanced Study and School of Systems Biology, George Mason University, Fairfax, VA, 22030, USA.,Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, 20201, USA
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Kao YH, Chung CC, Cheng WL, Lkhagva B, Chen YJ. Pitx2c inhibition increases atrial fibroblast activity: Implications in atrial arrhythmogenesis. Eur J Clin Invest 2019; 49:e13160. [PMID: 31378929 DOI: 10.1111/eci.13160] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 07/31/2019] [Indexed: 12/22/2022]
Abstract
BACKGROUND A Pitx2c deficiency increases the risk of atrial fibrillation (AF). Atrial structural remodelling with fibrosis blocks electrical conduction and leads to arrhythmogenesis. A Pitx2c deficiency enhances profibrotic transforming growth factor (TGF)-β expression and calcium dysregulation, suggesting that Pitx2c may play a role in atrial fibrosis. The purposes of this study were to evaluate whether a Pitx2c deficiency modulates cardiac fibroblast activity and study the underlying mechanisms. MATERIALS AND METHODS A migration assay, proliferation analysis, Western blot analysis and calcium fluorescence imaging were conducted in Pitx2c-knockdown human atrial fibroblasts (HAFs) using short hairpin (sh)RNA or small interfering (si)RNA. RESULTS Compared to control HAFs, Pitx2c-knockdown HAFs had a greater migration but a similar proliferative ability. Pitx2c-knockdown HAFs had a higher calcium influx with enhanced phosphorylation of calmodulin kinase II (CaMKII), α-smooth muscle actin and matrix metalloproteinase-2. In the presence of a CaMKII inhibitor (KN-93, 0.5 μmol/L), control and Pitx2c-knockdown HAFs exhibited similar migratory abilities. CONCLUSION These findings suggest that downregulation of Pitx2c may regulate atrial fibrosis through modulating calcium homeostasis, which may contribute to its role in anti-atrial fibrosis, and Pitx2c downregulation may change the atrial electrophysiology and AF occurrence through modulating fibroblast activity.
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Affiliation(s)
- Yu-Hsun Kao
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Department of Medical Research, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Cheng-Chih Chung
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Division of Cardiovascular Medicine, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Wan-Li Cheng
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Baigalmaa Lkhagva
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Yi-Jen Chen
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Division of Cardiovascular Medicine, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
- Cardiovascular Research Center, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
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Moghtadaei M, Polina I, Rose RA. Electrophysiological effects of natriuretic peptides in the heart are mediated by multiple receptor subtypes. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 120:37-49. [DOI: 10.1016/j.pbiomolbio.2015.12.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 11/25/2015] [Accepted: 12/02/2015] [Indexed: 12/13/2022]
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Liu H, Yang L, Chen KH, Sun HY, Jin MW, Xiao GS, Wang Y, Li GR. SKF-96365 blocks human ether-à-go-go-related gene potassium channels stably expressed in HEK 293 cells. Pharmacol Res 2015; 104:61-9. [PMID: 26689773 DOI: 10.1016/j.phrs.2015.12.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 11/19/2015] [Accepted: 12/07/2015] [Indexed: 11/18/2022]
Abstract
SKF-96365 is a TRPC channel antagonist commonly used to characterize the potential functions of TRPC channels in different systems, which was recently reported to induce QTc prolongation on ECG by inhibiting TRPC channels. The present study investigates whether the blockade of cardiac repolarization currents would be involved in the increase of QTc interval. Cardiac repolarization currents were recorded in HEK 293 cells stably expressing human ether-à-go-go-related gene potassium (hERG or hKv11.1) channels, hKCNQ1/hKCNE1 channels (IKs) or hKir2.1 channels and cardiac action potentials were recorded in guinea pig ventricular myocytes using a whole-cell patch technique. The potential effect of SKF-96365 on QT interval was evaluated in ex vivo guinea pig hearts. It was found that SKF-96365 inhibited hERG current in a concentration-dependent manner (IC50, 3.4μM). The hERG mutants S631A in the pore helix and F656V of the S6 region reduced the inhibitory sensitivity with IC50s of 27.4μM and 11.0μM, suggesting a channel pore blocker. In addition, this compound inhibited IKs and hKir2.1currents with IC50s of 10.8 and 8.7μM. SKF-96365 (10μM) significantly prolonged ventricular APD90 in guinea pig ventricular myocytes and QTc interval in ex vivo guinea pig hearts. These results indicate that the TRPC channel antagonist SKF-96365 exerts blocking effects on hERG, IKs, and hKir2.1 channels. Prolongation of ventricular APD and QT interval is related to the inhibition of multiple repolarization potassium currents, especially hERG channels.
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Affiliation(s)
- Hui Liu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Departments of Physiology and Medicine, Li Ka Shing Faculty of Medicine, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Lei Yang
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Departments of Physiology and Medicine, Li Ka Shing Faculty of Medicine, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Kui-Hao Chen
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Departments of Physiology and Medicine, Li Ka Shing Faculty of Medicine, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Hai-Ying Sun
- Departments of Physiology and Medicine, Li Ka Shing Faculty of Medicine, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Man-Wen Jin
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Guo-Sheng Xiao
- Xiamen Cardiovascular Hospital, Medical College of Xiamen University, Xiamen, China
| | - Yan Wang
- Xiamen Cardiovascular Hospital, Medical College of Xiamen University, Xiamen, China.
| | - Gui-Rong Li
- Departments of Physiology and Medicine, Li Ka Shing Faculty of Medicine, University of Hong Kong, Pokfulam, Hong Kong, China; Xiamen Cardiovascular Hospital, Medical College of Xiamen University, Xiamen, China.
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Teng G, Svystonyuk D, Mewhort HEM, Turnbull JD, Belke DD, Duff HJ, Fedak PWM. Tetrandrine reverses human cardiac myofibroblast activation and myocardial fibrosis. Am J Physiol Heart Circ Physiol 2015; 308:H1564-74. [PMID: 25862829 DOI: 10.1152/ajpheart.00126.2015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 04/03/2015] [Indexed: 11/22/2022]
Abstract
Tetrandrine (TTD) is a calcium channel blocker with documented antifibrotic actions. In this study, for the first time, we identified that TTD can directly prevent in vitro human cardiac myofibroblast activation and limit in vivo myocardial fibrosis. In vitro, cardiac myofibroblasts from human atrial biopsies (N = 10) were seeded in three-dimensional collagen matrices. Cell-collagen constructs were exposed to transforming growth factor-β1 (10 ng/ml), with or without TTD (1 and 5 μM) for 48 h. Collagen gel contraction, myofibroblast activation (α-smooth muscle actin expression), expression of profibrotic mRNAs, and rate of collagen protein synthesis were compared. TTD decreased collagen gel contraction (79.7 ± 1.3 vs 60.1 ± 8.9%, P < 0.01), α-smooth muscle actin expression (flow cytometry), collagen synthesis ([(3)H]proline incorporation), and collagen mRNA expression. Cell viability was similar between groups (annexin positive cells: 1.7 vs. 1.4%). TTD inhibited collagen gel contraction in the presence of T-type and L-type calcium channel blockers, and the intracellular calcium chelator BAPTA-AM (15 μM), suggesting that the observed effects are not mediated by calcium homeostasis. In vivo, Dahl salt-sensitive hypertensive rats were treated with variable doses of TTD (by intraperitoneal injection over 4 wk) and compared with untreated controls (N = 12). Systemic blood pressure was monitored by tail cuff. Myocardial fibrosis and left ventricular compliance were assessed by histology and passive pressure-volume analysis. Myocardial fibrosis was attenuated compared with untreated controls (%collagen area: 9.4 ± 7.3 vs 2.1 ± 1.0%, P < 0.01). Left ventricular compliance was preserved. In conclusion, TTD reverses human cardiac myofibroblast activation and myocardial fibrosis, independent of calcium channel blockade.
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Affiliation(s)
- Guoqi Teng
- Department of Cardiac Sciences, University of Calgary, Libin Cardiovascular Institute of Alberta, Calgary, Alberta, Canada
| | - Daniyil Svystonyuk
- Department of Cardiac Sciences, University of Calgary, Libin Cardiovascular Institute of Alberta, Calgary, Alberta, Canada
| | - Holly E M Mewhort
- Department of Cardiac Sciences, University of Calgary, Libin Cardiovascular Institute of Alberta, Calgary, Alberta, Canada
| | - Jeannine D Turnbull
- Department of Cardiac Sciences, University of Calgary, Libin Cardiovascular Institute of Alberta, Calgary, Alberta, Canada
| | - Darrell D Belke
- Department of Cardiac Sciences, University of Calgary, Libin Cardiovascular Institute of Alberta, Calgary, Alberta, Canada
| | - Henry J Duff
- Department of Cardiac Sciences, University of Calgary, Libin Cardiovascular Institute of Alberta, Calgary, Alberta, Canada
| | - Paul W M Fedak
- Department of Cardiac Sciences, University of Calgary, Libin Cardiovascular Institute of Alberta, Calgary, Alberta, Canada
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Chen KH, Liu H, Yang L, Jin MW, Li GR. SKF-96365 strongly inhibits voltage-gated sodium current in rat ventricular myocytes. Pflugers Arch 2014; 467:1227-36. [PMID: 25017106 DOI: 10.1007/s00424-014-1565-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 06/19/2014] [Accepted: 06/23/2014] [Indexed: 12/11/2022]
Abstract
SKF-96365 (1-(beta-[3-(4-methoxy-phenyl) propoxy]-4-methoxyphenethyl)-1H-imidazole hydrochloride) is a general TRPC channel antagonist commonly used to characterize the potential functions of TRPC channels in cardiovascular system. Recent reports showed that SKF-96365 induced a reduction in cardiac conduction. The present study investigates whether the reduced cardiac conduction caused by SKF-96365 is related to the blockade of voltage-gated sodium current (I Na) in rat ventricular myocytes using the whole-cell patch voltage-clamp technique. It was found that SKF-96365 inhibited I Na in rat ventricular myocytes in a concentration-dependent manner. The compound (1 μM) negatively shifted the potential of I Na availability by 9.5 mV, increased the closed-state inactivation of I Na, and slowed the recovery of I Na from inactivation. The inhibition of cardiac I Na by SKF-96365 was use-dependent and frequency-dependent, and the IC₅₀ was decreased from 1.36 μM at 0.5 Hz to 1.03, 0.81, 0.61, 0.56 μM at 1, 2, 5, 10 Hz, respectively. However, the selective TRPC3 antagonist Pyr3 decreased cardiac I Na by 8.5% at 10 μM with a weak use and frequency dependence. These results demonstrate that the TRPC channel antagonist SKF-96365 strongly blocks cardiac I Na in use-dependent and frequency-dependent manners. Caution should be taken for interpreting the alteration of cardiac electrical activity when SKF-96365 is used in native cells as a TRPC antagonist.
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Affiliation(s)
- Kui-Hao Chen
- Department of Physiology, Li Ka Shing Faculty of Medicine, University of Hong Kong, Laboratory Block, 21 Sassoon Road, Pokfulam, Hong Kong, China
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