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Sun X, Lee HC, Lu T. Sorbs2 Deficiency and Vascular BK Channelopathy in Diabetes. Circ Res 2024; 134:858-871. [PMID: 38362769 PMCID: PMC10978258 DOI: 10.1161/circresaha.123.323538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 02/02/2024] [Indexed: 02/17/2024]
Abstract
BACKGROUND Vascular large conductance Ca2+-activated K+ (BK) channel, composed of the α-subunit (BK-α) and the β1-subunit (BK-β1), is a key determinant of coronary vasorelaxation and its function is impaired in diabetic vessels. However, our knowledge of diabetic BK channel dysregulation is incomplete. The Sorbs2 (Sorbin homology [SoHo] and Src homology 3 [SH3] domains-containing protein 2), is ubiquitously expressed in arteries, but its role in vascular pathophysiology is unknown. METHODS The role of Sorbs2 in regulating vascular BK channel activity was determined using patch-clamp recordings, molecular biological techniques, and in silico analysis. RESULTS Sorbs2 is not only a cytoskeletal protein but also an RNA-binding protein that binds to BK channel proteins and BK-α mRNA, regulating BK channel expression and function in coronary smooth muscle cells. Molecular biological studies reveal that the SH3 domain of Sorbs2 is necessary for Sorbs2 interaction with BK-α subunits, while both the SH3 and SoHo domains of Sorbs2 interact with BK-β1 subunits. Deletion of the SH3 or SoHo domains abolishes the Sorbs2 effect on the BK-α/BK-β1 channel current density. Additionally, Sorbs2 is a target gene of the Nrf2 (nuclear factor erythroid-2-related factor 2), which binds to the promoter of Sorbs2 and regulates Sorbs2 expression in coronary smooth muscle cells. In vivo studies demonstrate that Sorbs2 knockout mice at 4 months of age display a significant decrease in BK channel expression and function, accompanied by impaired BK channel Ca2+-sensitivity and BK channel-mediated vasodilation in coronary arteries, without altering their body weights and blood glucose levels. Importantly, Sorbs2 expression is significantly downregulated in the coronary arteries of db/db type 2 diabetic mice. CONCLUSIONS Sorbs2, a downstream target of Nrf2, plays an important role in regulating BK channel expression and function in vascular smooth muscle cells. Vascular Sorbs2 is downregulated in diabetes. Genetic knockout of Sorbs2 manifests coronary BK channelopathy and vasculopathy observed in diabetic mice, independent of obesity and glucotoxicity.
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Affiliation(s)
- Xiaojing Sun
- The Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN
| | - Hon-Chi Lee
- The Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN
| | - Tong Lu
- The Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN
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Li XY, Qian LL, Wu Y, Zhang YM, Dang SP, Liu XY, Tang X, Lu CY, Wang RX. Advanced glycation end products impair coronary artery BK channels via AMPK/Akt/FBXO32 signaling pathway. Diab Vasc Dis Res 2023; 20:14791641231197107. [PMID: 37592725 PMCID: PMC10439763 DOI: 10.1177/14791641231197107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 08/19/2023] Open
Abstract
Background: Advanced glycation end products (AGEs) impair vascular physiology in Diabetes mellitus (DM). However, the underlying mechanisms remain unclear. Vascular large conductance calcium-activated potassium (BK) channels play important roles in coronary arterial function.Purpose: Our study aimed to investigate the regulatory role of AGEs in BK channels.Research Design: Using gavage of vehicle (V, normal saline) or aminoguanidine (A) for 8 weeks, normal and diabetic rats were divided into four groups: C+V group, DM+V group, C+A group, and DM+A group.Study Sample: Coronary arteries from different groups of rats and human coronary smooth muscle cells were used in this study.Data Collection and Analysis: Data were presented as mean ± SEM (standard error of mean). Student's t-test was used to compare data between two groups. One-way ANOVA with post-hoc LSD analysis was used to compare data between multiple groups.Results: Compared to the C+V group, vascular contraction induced by iberiotoxin (IBTX), a BK channel inhibitor, was impaired, and BK channel densities decreased in the DM+V group. However, aminoguanidine administration reduced the impairment. Protein expression of BK-β1, phosphorylation of adenosine 5'-monophosphate-activated protein kinase (AMPK), and protein kinase B (PKB or Akt) were down-regulated, while F-box protein 32 (FBXO32) expression increased in the DM+V group and in high glucose (HG) cultured human coronary smooth muscle cells. Treatment with aminoguanidine in vitro and in vivo could reverse the above protein expression. The effect of aminoguanidine on the improvement of BK channel function by inhibiting the generation of AGEs was reversed by adding MK2206 (Akt inhibitor) or Compound C (AMPK inhibitor) in HG conditions in vitro.Conclusions: AGEs aggravate BK channel dysfunction via the AMPK/Akt/FBXO32 signaling pathway.
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Affiliation(s)
- Xiao-Yan Li
- Department of Cardiology, The Affiliated Wuxi People’s Hospital of Nanjing Medical University, Wuxi, China
| | - Ling-Ling Qian
- Department of Cardiology, The Affiliated Wuxi People’s Hospital of Nanjing Medical University, Wuxi, China
| | - Ying Wu
- Department of Cardiology, The Affiliated Wuxi People’s Hospital of Nanjing Medical University, Wuxi, China
| | - Yu-Min Zhang
- Department of Cardiology, The Affiliated Wuxi People’s Hospital of Nanjing Medical University, Wuxi, China
| | - Shi-Peng Dang
- Department of Cardiology, The Affiliated Wuxi People’s Hospital of Nanjing Medical University, Wuxi, China
| | - Xiao-Yu Liu
- Department of Cardiology, The Affiliated Wuxi People’s Hospital of Nanjing Medical University, Wuxi, China
| | - Xu Tang
- Department of Cardiology, The Affiliated Wuxi People’s Hospital of Nanjing Medical University, Wuxi, China
| | - Cun-yu Lu
- Department of Cardiology, The Affiliated Wuxi People’s Hospital of Nanjing Medical University, Wuxi, China
| | - Ru-Xing Wang
- Department of Cardiology, The Affiliated Wuxi People’s Hospital of Nanjing Medical University, Wuxi, China
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Lu T, Lee HC. Coronary Large Conductance Ca 2+-Activated K + Channel Dysfunction in Diabetes Mellitus. Front Physiol 2021; 12:750618. [PMID: 34744789 PMCID: PMC8567020 DOI: 10.3389/fphys.2021.750618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/14/2021] [Indexed: 11/24/2022] Open
Abstract
Diabetes mellitus (DM) is an independent risk of macrovascular and microvascular complications, while cardiovascular diseases remain a leading cause of death in both men and women with diabetes. Large conductance Ca2+-activated K+ (BK) channels are abundantly expressed in arteries and are the key ionic determinant of vascular tone and organ perfusion. It is well established that the downregulation of vascular BK channel function with reduced BK channel protein expression and altered intrinsic BK channel biophysical properties is associated with diabetic vasculopathy. Recent efforts also showed that diabetes-associated changes in signaling pathways and transcriptional factors contribute to the downregulation of BK channel expression. This manuscript will review our current understandings on the molecular, physiological, and biophysical mechanisms that underlie coronary BK channelopathy in diabetes mellitus.
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Affiliation(s)
- Tong Lu
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, United States
| | - Hon-Chi Lee
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, United States
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4
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Ding Y, Yang J, Chen P, Lu T, Jiao K, Tester DJ, Giudicessi JR, Jiang K, Ackerman MJ, Li Y, Wang DW, Lee H, Wang DW, Xu X. Knockout of SORBS2 Protein Disrupts the Structural Integrity of Intercalated Disc and Manifests Features of Arrhythmogenic Cardiomyopathy. J Am Heart Assoc 2020; 9:e017055. [PMID: 32808564 PMCID: PMC7660791 DOI: 10.1161/jaha.119.017055] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 07/13/2020] [Indexed: 12/21/2022]
Abstract
Background Sorbs2b (sorbin and SH3 domain-containing 2b) was recently identified as a cardiomyopathy gene from a zebrafish mutagenesis screen. However, cardiac functions of its mammalian ortholog remain elusive. Methods and Results We conducted a detailed expression and subcellular localization analysis of Sorbs2 ortholog in mice and a phenotypic characterization in Sorbs2 knockout mice. Sorbs2 is highly expressed in the mouse heart and encodes an adhesion junction/desmosome protein that is mainly localized to the intercalated disc. A mutation with near complete depletion of the Sorbs2 protein in mice results in phenotypes characteristic of human arrhythmogenic cardiomyopathy (ACM), including right ventricular dilation, right ventricular dysfunction, spontaneous ventricular tachycardia, and premature death. Sorbs2 is required to maintain the structural integrity of intercalated disc. Its absence resulted in profound cardiac electrical remodeling with impaired impulse conduction and action potential derangements. Targeted sequencing of human patients with ACM identified 2 rare splicing variants classified as likely pathogenic were in 2 unrelated individuals with ACM from a cohort of 59 patients with ACM. Conclusions The Sorbs2 knockout mouse manifests several key features reminiscent of human ACM. Although the candidacy of SORBS2 as a new ACM-susceptibility gene is supported by preliminary human genetics study, future validation in larger cohorts with ACM is needed.
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Affiliation(s)
- Yonghe Ding
- Department of Biochemistry and Molecular BiologyMayo ClinicRochesterMN
- Department of Cardiovascular MedicineMayo ClinicRochesterMN
| | - Jingchun Yang
- Department of Biochemistry and Molecular BiologyMayo ClinicRochesterMN
- Department of Cardiovascular MedicineMayo ClinicRochesterMN
| | - Peng Chen
- Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic DisordersDivision of CardiologyDepartments of Internal Medicine and Genetic Diagnosis CenterTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Tong Lu
- Department of Cardiovascular MedicineMayo ClinicRochesterMN
| | - Kunli Jiao
- Department of Biochemistry and Molecular BiologyMayo ClinicRochesterMN
- Department of Cardiovascular MedicineMayo ClinicRochesterMN
- Division of CardiologyXinhua HospitalShanghai Jiaotong UniversityShanghaiChina
| | | | | | - Kai Jiang
- Division of Nephrology and HypertensionMayo ClinicRochesterMN
| | - Michael J. Ackerman
- Department of Cardiovascular Medicine (Division of Heart Rhythm Services)Mayo ClinicRochesterMN
- Pediatric and Adolescent Medicine (Division of Pediatric Cardiology)Mayo ClinicRochesterMN
- Molecular Pharmacology and Experimental Therapeutics (Windland Smith Rice Sudden Death Genomics Laboratory)Mayo ClinicRochesterMN
| | - Yigang Li
- Division of CardiologyXinhua HospitalShanghai Jiaotong UniversityShanghaiChina
| | - Dao Wu Wang
- State Key Laboratory of Reproductive MedicineClinical Center of Reproductive Medicine and Department of CardiologyFirst Affiliated Hospital of Nanjing Medical UniversityNanjingChina
| | - HoN‐chi Lee
- Department of Cardiovascular MedicineMayo ClinicRochesterMN
| | - Dao Wen Wang
- Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic DisordersDivision of CardiologyDepartments of Internal Medicine and Genetic Diagnosis CenterTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Xiaolei Xu
- Department of Biochemistry and Molecular BiologyMayo ClinicRochesterMN
- Department of Cardiovascular MedicineMayo ClinicRochesterMN
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Glucose fluctuations promote vascular BK channels dysfunction via PKCα/NF-κB/MuRF1 signaling. J Mol Cell Cardiol 2020; 145:14-24. [PMID: 32511969 DOI: 10.1016/j.yjmcc.2020.05.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 05/27/2020] [Accepted: 05/31/2020] [Indexed: 01/01/2023]
Abstract
Glucose fluctuations may contribute to large conductance calcium activated potassium (BK) channel dysfunction. However, the underlying mechanisms remain elusive. The aim of this study was to investigate the molecular mechanisms involved in BK channel dysfunction as a result of glucose fluctuations. A rat diabetic model was established through the injection of streptozotocin. Glucose fluctuations in diabetic rats were induced via consumption and starvation. Rat coronary arteries were isolated and coronary vascular tensions were measured after three weeks. Rat coronary artery smooth muscle cells were isolated and whole-cell BK channel currents were recorded using a patch clamp technique. Human coronary artery smooth muscle cells in vitro were used to explore the underlying mechanisms. After incubation with iberiotoxin (IBTX), the Δ tensions (% Max) of rat coronary arteries in the controlled diabetes mellitus (C-DM), the uncontrolled DM (U-DM) and the DM with glucose fluctuation (GF-DM) groups were found to be 84.46 ± 5.75, 61.89 ± 10.20 and 14.77 ± 5.90, respectively (P < .05), while the current densities of the BK channels in the three groups were 43.09 ± 4.35 pA/pF, 34.23 ± 6.07 pA/pF and 17.87 ± 4.33 pA/pF, respectively (P < .05). The Δ tensions (% Max) of rat coronary arteries after applying IBTX in the GF-DM rats injected with 0.9% sodium chloride (NaCl) (GF-DM + NaCl) and the GF-DM rats injected with N-acetyl-L-cysteine (NAC) (GF-DM + NAC) groups were found to be 8.86 ± 1.09 and 48.90 ± 10.85, respectively (P < .05). Excessive oxidative stress and the activation of protein kinase C (PKC) α and nuclear factor (NF)-κB induced by glucose fluctuations promoted the decrease of BK-β1 expression, while the inhibition of reactive oxygen species (ROS), PKCα, NF-κB and muscle ring finger protein 1 (MuRF1) reversed this effect. Glucose fluctuations aggravate BK channel dysfunction via the ROS overproduction and the PKCα/NF-κB/MuRF1 signaling pathway.
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6
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Qian LL, Liu XY, Yu ZM, Wang RX. BK Channel Dysfunction in Diabetic Coronary Artery: Role of the E3 Ubiquitin Ligases. Front Physiol 2020; 11:453. [PMID: 32547406 PMCID: PMC7274077 DOI: 10.3389/fphys.2020.00453] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 04/09/2020] [Indexed: 01/11/2023] Open
Abstract
Diabetic coronary arterial disease is a leading cause of morbidity and mortality in diabetic patients. The impaired function of large-conductance calcium-activated potassium channels (BK channels) is involved in diabetic coronary arterial disease. Many studies have indicated that the reduced BK channel expression in diabetic coronary artery is attributed to ubiquitin-mediated protein degradation by the ubiquitin-proteasome system. This review focuses on the influence and the mechanisms of BK channel regulation by E3 ubiquitin ligases in diabetic coronary arterial disease. Thus, BK channels regulated by E3 ubiquitin ligase may play a pivotal role in the coronary pathogenesis of diabetic mellitus and, as such, is a potentially attractive target for therapeutic intervention.
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Affiliation(s)
| | | | | | - Ru-xing Wang
- Department of Cardiology, Wuxi People’s Hospital Affiliated to Nanjing Medical University, Wuxi, China
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7
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Sun X, Qian LL, Li Y, Pfiefer TM, Wang XL, Lee HC, Lu T. Regulation of KCNMA1 transcription by Nrf2 in coronary arterial smooth muscle cells. J Mol Cell Cardiol 2020; 140:68-76. [PMID: 32147517 DOI: 10.1016/j.yjmcc.2020.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 02/21/2020] [Accepted: 03/03/2020] [Indexed: 02/08/2023]
Abstract
The large conductance Ca2+-activated K+ (BK) channels, composed of the pore-forming α subunits (BK-α, encoded by KCNMA1 gene) and the regulatory β1 subunits (BK-β1, encoded by KCNMB1 gene), play a unique role in the regulation of coronary vascular tone and myocardial perfusion by linking intracellular Ca2+ homeostasis with excitation-contraction coupling in coronary arterial smooth muscle cells (SMCs). The nuclear factor erythroid 2-related factor 2 (Nrf2) belongs to a member of basic leucine zipper transcription factor family that regulates the expression of antioxidant and detoxification enzymes by binding to the antioxidant response elements (AREs) of these target genes. We have previously reported that vascular BK-β1 protein expression was tightly regulated by Nrf2. However, the molecular mechanism underlying the regulation of BK channel expression by Nrf2, particularly at transcription level, is unknown. In this study, we hypothesized that KCNMA1 and KCNMB1 are the target genes of Nrf2 transcriptional regulation. We found that BK channel protein expression and current density were diminished in freshly isolated coronary arterial SMCs of Nrf2 knockout (KO) mice. However, BK-α mRNA expression was reduced, but not that of BK-β1 mRNA expression, in the arteries of Nrf2 KO mice. Promoter-Nrf2 luciferase reporter assay confirmed that Nrf2 binds to the ARE of KCNMA1 promoter, but not that of KCNMB1. Adenoviral expression and pharmacological activation of Nrf2 increased BK-α and BK-β1 protein levels and enhanced BK channel activity in coronary arterial SMCs. Hence, our results indicate that Nrf2 is a key determinant of BK channel expression and function in vascular SMCs. Nrf2 facilitates BK-α expression through a direct increase in gene transcription, whereas that on BK-β1 is through a different mechanism.
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Affiliation(s)
- Xiaojing Sun
- The Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester 55905, MN, USA
| | - Ling-Ling Qian
- The Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester 55905, MN, USA; The Department of Cardiology, Wuxi People's Hospital Affiliated to Nanjing Medical University, 299 Qingyang Road, Wuxi 214023, Jiangsu Province, PR China
| | - Yong Li
- The Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester 55905, MN, USA; The Department of Cardiology, the Affiliated Wujin Hospital of Jiangsu University, Changzhou 213017, Jiangsu Province, PR China
| | - Teresa M Pfiefer
- The Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester 55905, MN, USA
| | - Xiao-Li Wang
- The Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester 55905, MN, USA
| | - Hon-Chi Lee
- The Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester 55905, MN, USA
| | - Tong Lu
- The Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester 55905, MN, USA.
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8
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Lu T, Chai Q, Jiao G, Wang XL, Sun X, Furuseth JD, Stulak JM, Daly RC, Greason KL, Cha YM, Lee HC. Downregulation of BK channel function and protein expression in coronary arteriolar smooth muscle cells of type 2 diabetic patients. Cardiovasc Res 2020; 115:145-153. [PMID: 29850792 DOI: 10.1093/cvr/cvy137] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 05/22/2018] [Indexed: 12/20/2022] Open
Abstract
Aims Type 2 diabetes (T2D) is strongly associated with cardiovascular morbidity and mortality in patients. Vascular large conductance Ca2+-activated potassium (BK) channels, composed of four pore-forming α subunits (BK-α), and four regulatory β1 subunits (BK-β1), are densely expressed in coronary arterial smooth muscle cells (SMCs) and play an important role in regulating vascular tone and myocardial perfusion. However, the role of BK channels in coronary microvascular dysfunction of human subjects with diabetes is unclear. In this study, we examined BK channel function and protein expression, and BK channel-mediated vasodilation in freshly isolated coronary arterioles from T2D patients. Methods and results Atrial tissues were obtained from 16 patients with T2D and 25 matched non-diabetic subjects during cardiopulmonary bypass procedure. Microvessel videomicroscopy and immunoblot analysis were performed in freshly dissected coronary arterioles and inside-out single BK channel currents was recorded in enzymatically isolated coronary arteriolar SMCs. We found that BK channel sensitivity to physiological Ca2+ concentration and voltage was downregulated in the coronary arteriolar SMCs of diabetic patients, compared with non-diabetic controls. BK channel kinetics analysis revealed that there was significant shortening of the mean open time and prolongation of the mean closed time in diabetic patients, resulting in a remarkable reduction of the channel open probability. Functional studies showed that BK channel activation by dehydrosoyasaponin-1 was diminished and that BK channel-mediated vasodilation in response to shear stress was impaired in diabetic coronary arterioles. Immunoblot experiments confirmed that the protein expressions of BK-α and BK-β1 subunits were significantly downregulated, but the ratio of BK-α/BK-β1 was unchanged in the coronary arterioles of T2D patients. Conclusions Our results demonstrated for the first time that BK channel function and BK channel-mediated vasodilation were abnormal in the coronary microvasculature of diabetic patients, due to decreased protein expression and altered intrinsic properties of BK channels.
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Affiliation(s)
- Tong Lu
- Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW., Rochester, Minnesota, USA
| | - Qiang Chai
- Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW., Rochester, Minnesota, USA.,Department of Physiology, Institute of Basic Medicine, Shandong Academy of Medical Sciences, 89 Jingshi Road, Jinan, Shandong, PR China
| | - Guoqing Jiao
- Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW., Rochester, Minnesota, USA.,Department of Cardiovascular Surgery, Wuxi People's Hospital Affiliated to Nanjing Medical University, 299 Qingyang Road, Wuxi, Jiangsu, PR China
| | - Xiao-Li Wang
- Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW., Rochester, Minnesota, USA
| | - Xiaojing Sun
- Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW., Rochester, Minnesota, USA
| | - Jonathan D Furuseth
- Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW., Rochester, Minnesota, USA
| | - John M Stulak
- Department of Cardiovascular Surgery, Mayo Clinic, 200 First Street, SW., Rochester, Minnesota, USA
| | - Richard C Daly
- Department of Cardiovascular Surgery, Mayo Clinic, 200 First Street, SW., Rochester, Minnesota, USA
| | - Kevin L Greason
- Department of Cardiovascular Surgery, Mayo Clinic, 200 First Street, SW., Rochester, Minnesota, USA
| | - Yong-Mei Cha
- Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW., Rochester, Minnesota, USA
| | - Hon-Chi Lee
- Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW., Rochester, Minnesota, USA
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Chen K, Sun Y, Diao Y, Zhang T, Dong W. Hydrogen-rich solution attenuates myocardial injury caused by cardiopulmonary bypass in rats via the Janus-activated kinase 2/signal transducer and activator of transcription 3 signaling pathway. Oncol Lett 2018; 16:167-178. [PMID: 29928398 PMCID: PMC6006345 DOI: 10.3892/ol.2018.8639] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 03/14/2018] [Indexed: 12/18/2022] Open
Abstract
The incidence of complications and mortality following open-heart surgery with cardiopulmonary bypass (CPB) is associated with the severity of the myocardial injury that occurs during surgery. Hydrogen-rich solution (HRS) may prevent antioxidant stress and inhibit apoptosis and inflammation. The present study was designed to investigate the effects of HRS on CPB-induced myocardial injury, and to investigate its potential regulation of the Janus-activated kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway. The HRS treatment resulted in the significant upregulation of malonyl dialdehyde (MDA) and myeloperoxidase (MPO), whilesuperoxide dismutase (SOD) levels were significantly downregulated, compared with the Sham group (P<0.05). Additionally, HRS treatment improved myocardial injury, and decreased the expression levels of cardiac troponins, heart-type fatty acid binding protein, interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, MDA and MPO, and increased SOD release in CPB rats (P<0.05). Additionally, in the CPB group without the HRS treatment, the expression levels of B-cell lymphoma (Bcl)-2, JAK2, phospho-JAK2 (p-JAK2), STAT3 and phospho-STAT3 (p-STAT3) were significantly decreased, and Bax was significantly increased, compared with the Sham group (P<0.05). By contrast, compared with the CPB group, the expression levels of B-cell lymphoma 2 (Bcl-2), JAK2, phosphorylated (p)-JAK2, STAT3 and p-STAT3 in the HRS group were significantly increased, and Bcl-2-associated X protein expression was significantly decreased (P<0.05). In JAK2 knockdown experiments using siRNA, HRS treatment following hypoxia/reoxygenation also significantly increased the viability of myocardial cells, decreased the rate of myocardial cell apoptosis, elevated the levels of SOD and suppressed the release of MDA and lactate dehydrogenase in the control siRNA and CPB groups (P<0.05). Furthermore, JAK2 siRNA attenuated these protective effects of HRS (P<0.05 vs. control siRNA, HRS and CPB groups). Additionally, the results demonstrated that the HRS treatment significantly increased the expression levels of p-JAK2, p-STAT3 and Bcl-2 in myocardial cells following hypoxia and decreased Bax expression in the control siRNA and CPB groups (P<0.05). In addition, JAK2 siRNA was determined to attenuate these effects of HRS (P<0.05 vs. control siRNA, HRS and CPB groups). Taken together, these results indicated that HRS may alleviate CPB-induced myocardial injury, inhibit myocardial cell apoptosis and protect myocardial cells through regulation of the JAK2/STAT3 signaling pathway.
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Affiliation(s)
- Keyan Chen
- Department of Laboratory Animal Science, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Yingjie Sun
- Department of Anesthesiology, General Hospital of Shenyang Military Area Command, Shenyang, Liaoning 110016, P.R. China
| | - Yugang Diao
- Department of Anesthesiology, General Hospital of Shenyang Military Area Command, Shenyang, Liaoning 110016, P.R. China
| | - Tiezheng Zhang
- Department of Anesthesiology, General Hospital of Shenyang Military Area Command, Shenyang, Liaoning 110016, P.R. China
| | - Wanwei Dong
- Department of Laboratory Animal Science, China Medical University, Shenyang, Liaoning 110122, P.R. China
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10
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Zhu Y, Ye P, Chen SL, Zhang DM. Functional regulation of large conductance Ca 2+-activated K + channels in vascular diseases. Metabolism 2018; 83:75-80. [PMID: 29373813 DOI: 10.1016/j.metabol.2018.01.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Revised: 01/03/2018] [Accepted: 01/18/2018] [Indexed: 12/17/2022]
Abstract
The large conductance Ca2+-activated potassium channels, the BK channels, is widely expressed in various tissues and activated in a Ca2+- and voltage-dependent manner. The activation of BK channels hyperpolarizes vascular smooth muscle cell membrane potential, resulting in vasodilation. Under pathophysiological conditions, such as diabetes mellitus and hypertension, impaired BK channel function exacerbates vascular vasodilation and leads to organ ischemia. The vascular BK channel is composed of 4 pore-forming subunits, BK-α together with 4 auxiliary subunits: β1 subunits (BK-β1) or γ1 subunits (BK-γ1). Recent studies have shown that down-regulation of the BK β1 subunit in diabetes mellitus induced vascular dysfunction; however, the molecular mechanism of these vascular diseases is not well understood. In this review, we summarize the potential mechanisms regarding BK channelopathy and the potential therapeutic targets of BK channels for vascular diseases.
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Affiliation(s)
- Yanrong Zhu
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu 210006, China
| | - Peng Ye
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu 210006, China
| | - Shao-Liang Chen
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu 210006, China
| | - Dai-Min Zhang
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu 210006, China.
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Severino P, D'Amato A, Netti L, Pucci M, De Marchis M, Palmirotta R, Volterrani M, Mancone M, Fedele F. Diabetes Mellitus and Ischemic Heart Disease: The Role of Ion Channels. Int J Mol Sci 2018. [PMID: 29534462 PMCID: PMC5877663 DOI: 10.3390/ijms19030802] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Diabetes mellitus is one the strongest risk factors for cardiovascular disease and, in particular, for ischemic heart disease (IHD). The pathophysiology of myocardial ischemia in diabetic patients is complex and not fully understood: some diabetic patients have mainly coronary stenosis obstructing blood flow to the myocardium; others present with coronary microvascular disease with an absence of plaques in the epicardial vessels. Ion channels acting in the cross-talk between the myocardial energy state and coronary blood flow may play a role in the pathophysiology of IHD in diabetic patients. In particular, some genetic variants for ATP-dependent potassium channels seem to be involved in the determinism of IHD.
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Affiliation(s)
- Paolo Severino
- Department of Cardiovascular, Respiratory, Nephrology, Anesthesiology and Geriatric Sciences, Sapienza University of Rome, 00161 Rome, Italy.
| | - Andrea D'Amato
- Department of Cardiovascular, Respiratory, Nephrology, Anesthesiology and Geriatric Sciences, Sapienza University of Rome, 00161 Rome, Italy.
| | - Lucrezia Netti
- Department of Cardiovascular, Respiratory, Nephrology, Anesthesiology and Geriatric Sciences, Sapienza University of Rome, 00161 Rome, Italy.
| | - Mariateresa Pucci
- Department of Cardiovascular, Respiratory, Nephrology, Anesthesiology and Geriatric Sciences, Sapienza University of Rome, 00161 Rome, Italy.
| | - Marialaura De Marchis
- Department of Cardiovascular, Respiratory, Nephrology, Anesthesiology and Geriatric Sciences, Sapienza University of Rome, 00161 Rome, Italy.
| | - Raffaele Palmirotta
- Department of Biomedical Sciences and Clinical Oncology Oncogenomic Research Center, 'Aldo Moro' University of Bari, 70124 Bari, Italy.
| | - Maurizio Volterrani
- Department of Cardiac Rehabilitation, IRCCS San Raffaele, 00163 Rome, Italy.
| | - Massimo Mancone
- Department of Cardiovascular, Respiratory, Nephrology, Anesthesiology and Geriatric Sciences, Sapienza University of Rome, 00161 Rome, Italy.
| | - Francesco Fedele
- Department of Cardiovascular, Respiratory, Nephrology, Anesthesiology and Geriatric Sciences, Sapienza University of Rome, 00161 Rome, Italy.
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Lu T, Sun X, Li Y, Chai Q, Wang XL, Lee HC. Role of Nrf2 Signaling in the Regulation of Vascular BK Channel β1 Subunit Expression and BK Channel Function in High-Fat Diet-Induced Diabetic Mice. Diabetes 2017; 66:2681-2690. [PMID: 28465407 PMCID: PMC5606315 DOI: 10.2337/db17-0181] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 04/17/2017] [Indexed: 01/13/2023]
Abstract
The large conductance Ca2+-activated K+ (BK) channel β1-subunit (BK-β1) is a key modulator of BK channel electrophysiology and the downregulation of BK-β1 protein expression in vascular smooth muscle cells (SMCs) underlies diabetic vascular dysfunction. In this study, we hypothesized that the nuclear factor erythroid-2-related factor 2 (Nrf2) signaling pathway plays a significant role in the regulation of coronary BK channel function and vasodilation in high-fat diet (HFD)-induced obese/diabetic mice. We found that the protein expressions of BK-β1 and Nrf2 were markedly downregulated, whereas those of the nuclear factor-κB (NF-κB) and the muscle ring finger protein 1 (MuRF1 [a ubiquitin E3 ligase for BK-β1]) were significantly upregulated in HFD mouse arteries. Adenoviral expression of Nrf2 suppressed the protein expressions of NF-κB and MuRF1 but enhanced BK-β1 mRNA and protein expressions in cultured coronary SMCs. Knockdown of Nrf2 resulted in reciprocal changes of these proteins. Patch-clamp studies showed that coronary BK-β1-mediated channel activation was diminished in HFD mice. Importantly, the activation of Nrf2 by dimethyl fumarate significantly reduced the body weight and blood glucose levels of HFD mice, enhanced BK-β1 transcription, and attenuated MuRF1-dependent BK-β1 protein degradation, which in turn restored coronary BK channel function and BK channel-mediated coronary vasodilation in HFD mice. Hence, Nrf2 is a novel regulator of BK channel function with therapeutic implications in diabetic vasculopathy.
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Affiliation(s)
- Tong Lu
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN
| | - Xiaojing Sun
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN
| | - Yong Li
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN
- Department of Cardiology, The Affiliated Wujin Hospital of Jiangsu University, Changzhou, Jiangsu, People's Republic of China
| | - Qiang Chai
- Department of Physiology, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan, Shandong, People's Republic of China
| | - Xiao-Li Wang
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN
| | - Hon-Chi Lee
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN
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13
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Zhang ZY, Qian LL, Wang RX. Molecular Mechanisms Underlying Renin-Angiotensin-Aldosterone System Mediated Regulation of BK Channels. Front Physiol 2017; 8:698. [PMID: 28955251 PMCID: PMC5601423 DOI: 10.3389/fphys.2017.00698] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 08/30/2017] [Indexed: 12/21/2022] Open
Abstract
Large-conductance calcium-activated potassium channels (BK channels) belong to a family of Ca2+-sensitive voltage-dependent potassium channels and play a vital role in various physiological activities in the human body. The renin-angiotensin-aldosterone system is acknowledged as being vital in the body's hormone system and plays a fundamental role in the maintenance of water and electrolyte balance and blood pressure regulation. There is growing evidence that the renin-angiotensin-aldosterone system has profound influences on the expression and bioactivity of BK channels. In this review, we focus on the molecular mechanisms underlying the regulation of BK channels mediated by the renin-angiotensin-aldosterone system and its potential as a target for clinical drugs.
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Affiliation(s)
- Zhen-Ye Zhang
- Department of Cardiology, Wuxi People's Hospital Affiliated to Nanjing Medical UniversityWuxi, China
| | - Ling-Ling Qian
- Department of Cardiology, Wuxi People's Hospital Affiliated to Nanjing Medical UniversityWuxi, China
| | - Ru-Xing Wang
- Department of Cardiology, Wuxi People's Hospital Affiliated to Nanjing Medical UniversityWuxi, China
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14
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Li Y, Wang XL, Sun X, Chai Q, Li J, Thompson B, Shen WK, Lu T, Lee HC. Regulation of vascular large-conductance calcium-activated potassium channels by Nrf2 signalling. Diab Vasc Dis Res 2017; 14:353-362. [PMID: 28429615 DOI: 10.1177/1479164117703903] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
BK channels are major ionic determinants of vasodilation. BK channel function is impaired in diabetic vessels due to accelerated proteolysis of its beta-1 (BK-β1) subunits in response to increased oxidative stress. The nuclear factor E2-related factor-2 (Nrf2) signalling pathway has emerged as a master regulator of cellular redox status, and we hypothesized that it plays a central role in regulating BK channel function in diabetic vessels. We found that Nrf2 expression was markedly reduced in db/db diabetic mouse aortas, and this was associated with significant downregulation of BK-β1. In addition, the muscle ring finger protein 1 (MuRF1), a known E-3 ligase targeting BK-β1 ubiquitination and proteasomal degradation, was significantly augmented. These findings were reproduced by knockdown of Nrf2 by siRNA in cultured human coronary artery smooth muscle cells. In contrast, adenoviral transfer of Nrf2 gene in these cells downregulated MuRF1 and upregulated BK-β1 expression. Activation of Nrf2 by dimethyl fumarate preserved BK-β1 expression and protected BK channel and vascular function in db/db coronary arteries. These results indicate that expression of BK-β1 is closely regulated by Nrf2 and vascular BK channel function can be restored by Nrf2 activation. Nrf2 should be considered a novel therapeutic target in the treatment of diabetic vasculopathy.
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Affiliation(s)
- Yong Li
- 1 Department of Cardiology, Affiliated Wujin Hospital of Jiangsu University, Changzhou, China
- 2 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Xiao-Li Wang
- 2 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Xiaojing Sun
- 2 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Qiang Chai
- 2 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
- 3 Department of Physiology, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan, P.R. China
| | - Jingchao Li
- 2 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
- 4 Department of Emergency Medicine, Henan Provincial People's Hospital, Affiliated Hospital of Zhengzhou University, Zhengzhou, P.R. China
| | - Benjamin Thompson
- 2 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Win-Kuang Shen
- 5 Department of Cardiovascular Medicine, Mayo Clinic, Scottsdale, AZ, USA
| | - Tong Lu
- 2 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Hon-Chi Lee
- 2 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
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