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Van NTH, Kim WK, Nam JH. Challenges in the Therapeutic Targeting of KCa Channels: From Basic Physiology to Clinical Applications. Int J Mol Sci 2024; 25:2965. [PMID: 38474212 PMCID: PMC10932353 DOI: 10.3390/ijms25052965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 01/23/2024] [Accepted: 01/25/2024] [Indexed: 03/14/2024] Open
Abstract
Calcium-activated potassium (KCa) channels are ubiquitously expressed throughout the body and are able to regulate membrane potential and intracellular calcium concentrations, thereby playing key roles in cellular physiology and signal transmission. Consequently, it is unsurprising that KCa channels have been implicated in various diseases, making them potential targets for pharmaceutical interventions. Over the past two decades, numerous studies have been conducted to develop KCa channel-targeting drugs, including those for disorders of the central and peripheral nervous, cardiovascular, and urinary systems and for cancer. In this review, we synthesize recent findings regarding the structure and activating mechanisms of KCa channels. We also discuss the role of KCa channel modulators in therapeutic medicine. Finally, we identify the major reasons behind the delay in bringing these modulators to the pharmaceutical market and propose new strategies to promote their application.
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Affiliation(s)
- Nhung Thi Hong Van
- Department of Physiology, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea;
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, Goyang 10326, Republic of Korea
| | - Woo Kyung Kim
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, Goyang 10326, Republic of Korea
- Department of Internal Medicine, Graduate School of Medicine, Dongguk University, Goyang 10326, Republic of Korea
| | - Joo Hyun Nam
- Department of Physiology, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea;
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, Goyang 10326, Republic of Korea
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Wang M, Li S, Liu H, Liu M, Zhang J, Wu Y, Xiao C, Huang H. Large-conductance Ca 2 +-activated K + channel β1-subunit maintains the contractile phenotype of vascular smooth muscle cells. Front Cardiovasc Med 2022; 9:1062695. [PMID: 36568562 PMCID: PMC9780463 DOI: 10.3389/fcvm.2022.1062695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 11/24/2022] [Indexed: 12/14/2022] Open
Abstract
Background Vascular smooth muscle cells (VSMCs) phenotype switching is very important during the pathogenesis and progression of vascular diseases. However, it is not well understood how normal VSMCs maintain the differentiated state. The large-conductance Ca2+-activated K+ (BKCa) channels are widely expressed in VSMCs and regulate vascular tone. Nevertheless, there is limited understanding of the role of the BKCa channel in modulation of the VSMC phenotype. Methods and results We assessed BKCa channel expression levels in normal and injured carotid arteries from rats of the balloon-injury model. A strong decrease of BKCa-β1 was seen in the injured carotid arteries, accompanied by a parallel decrease of the VSMC contractile markers. BKCa-β1 in primary rat aortic VSMCs was decreased with the increase of passage numbers and the stimulation of platelet-derived growth factor (PDGF)-BB. Conversely, transforming growth factor β upregulated BKCa-β1. Meanwhile, the BKCa-β1 level was positively associated with the levels of VSMC contractile proteins. Intravenous injection of PDGF-BB induced downregulation of BKCa-β1 expression in the carotid arteries. Knockdown of BKCa-β1 favored VSMC dedifferentiation, characterized by altered morphology, abnormal actin fiber organization, decreased contractile proteins expression and reduced contractile ability. Furthermore, the resultant VSMC dedifferentiated phenotype rendered increased proliferation, migration, enhanced inflammatory factors levels, and matrix metalloproteinases activity. Studies using primary cultured aortic VSMCs from human recapitulated key findings. Finally, protein level of BKCa-β1 was reduced in human atherosclerotic arteries. Conclusion BKCa-β1 is important in the maintenance of the contractile phenotype of VSMCs. As a novel endogenous defender that prevents pathological VSMC phenotype switching, BKCa-β1 may serve as a potential therapeutic target for treating vascular diseases including post-injury restenosis and atherosclerosis.
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Affiliation(s)
- Meili Wang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Shuanglei Li
- Division of Adult Cardiac Surgery, Department of Cardiology, The Sixth Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Hongshan Liu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Mingyuan Liu
- Department of Vascular Surgery, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Jin Zhang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Yang Wu
- Division of Adult Cardiac Surgery, Department of Cardiology, The Sixth Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Cangsong Xiao
- Division of Adult Cardiac Surgery, Department of Cardiology, The Sixth Medical Center, Chinese PLA General Hospital, Beijing, China,Cangsong Xiao,
| | - Haixia Huang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China,*Correspondence: Haixia Huang,
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Song A, Wang J, Tong Y, Fang J, Zhang Y, Zhang H, Ruan H, Wang K, Liu Y. BKCa channels regulate the immunomodulatory properties of WJ-MSCs by affecting the exosome protein profiles during the inflammatory response. Stem Cell Res Ther 2020; 11:440. [PMID: 33059770 PMCID: PMC7560248 DOI: 10.1186/s13287-020-01952-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 09/24/2020] [Indexed: 12/13/2022] Open
Abstract
Background Wharton’s jelly-derived mesenchymal stem cells (WJ-MSCs) from the human umbilical cord have been studied extensively due to their immunomodulatory functions. Large-conductance Ca2+-activated K+ (BKCa channels) channels are involved in many inflammatory responses, but their involvement in the anti-inflammatory activity of WJ-MSCs is unknown. The underlying molecular mechanism, through which BKCa channels mediate the immunomodulation of WJ-MSC, which may include changes in exosomes proteomics, has not yet been clarified. Methods Alizarin staining, Oil Red O staining, and flow cytometry were used to identify WJ-MSCs, which were isolated from human umbilical cord Wharton’s jelly. BKCa channels were detected in WJ-MSCs using western blotting, real-time polymerase chain reaction (real-time PCR), and electrophysiology, and cytokine expression was examined using real-time PCR and enzyme-linked immunosorbent assays (ELISAs). Exosomes were characterized using transmission electron microscopy and nanoparticle tracking analysis. Proteomics analysis was performed to explore exosomal proteomic profiles. Results The cells derived from human umbilical cord Wharton’s jelly were identified as MSCs. BKCa channels were detected in the isolated WJ-MSCs, and the expression of these channels increased after lipopolysaccharide (LPS) stimulation. BKCa channels blockade in LPS-treated WJ-MSCs induced apoptosis and decreased interleukin-6 (IL-6) expression. Furthermore, THP-1 cells (human monocytic cell line) stimulated with LPS/interferon gamma (IFN-γ) produced more anti-inflammatory cytokines after treatment with exosomes derived from BKCa channel-knockdown WJ-MSCs (si-exo). We also observed altered expression of mitochondrial ATP synthase alpha subunit (ATP5A1), filamin B, and other proteins in si-exo, which might increase the anti-inflammatory activity of macrophages. Conclusions Our study described the functional expression of BKCa channels in WJ-MSCs, and BKCa channels regulated the immunomodulatory properties of WJ-MSCs by affecting the exosomal protein profiles during the inflammatory response.
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Affiliation(s)
- Ahui Song
- Department of Nephrology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Road, Shanghai, People's Republic of China
| | - Jingjing Wang
- Department of Nephrology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Road, Shanghai, People's Republic of China
| | - Yan Tong
- Department of Nephrology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Road, Shanghai, People's Republic of China
| | - Junyan Fang
- Department of Nephrology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Road, Shanghai, People's Republic of China
| | - Yi Zhang
- Shanghai Applied Protein Technology Co., Ltd.,Research & Development Center, 58 Yuanmei Road, Shanghai, People's Republic of China
| | - Huiping Zhang
- Shanghai Applied Protein Technology Co., Ltd.,Research & Development Center, 58 Yuanmei Road, Shanghai, People's Republic of China
| | - Hongqiang Ruan
- Shanghai Applied Protein Technology Co., Ltd.,Research & Development Center, 58 Yuanmei Road, Shanghai, People's Republic of China
| | - Kai Wang
- The Clinical and Translational Research Center Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China
| | - Yingli Liu
- Department of Nephrology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Road, Shanghai, People's Republic of China.
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Zhao H, Xue Q, Li C, Wang Q, Han S, Zhou Y, Yang T, Xie Y, Fu H, Lu C, Meng F, Zhang M, Zhang Y, Wu X, Wu S, Zhuo M, Xu H. Upregulation of Beta4 subunit of BK Ca channels in the anterior cingulate cortex contributes to mechanical allodynia associated anxiety-like behaviors. Mol Brain 2020; 13:22. [PMID: 32070382 PMCID: PMC7029562 DOI: 10.1186/s13041-020-0555-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 01/19/2020] [Indexed: 12/02/2022] Open
Abstract
The anterior cingulate cortex (ACC) serves as a critical hub for the anxiety and pain perception. The large-conductance Ca2+-activated potassium channels, or BKCa channels, are ubiquitously expressed throughout the central nervous system including the cingulate cortex. However, what changes of cortical BKCa channels undergo in the ACC remains unknown in pain-related anxiety. In the present study, a significant upregulation of synaptic and non-synaptic BKCa channel accessory β4 subunits in the ACC was accompanied with pain-associated anxiety-like behaviors in the chronic compression of multiple dorsal root ganglia (mCCD) of the rat. NS1619, an opener of BKCa channels, significantly rescued the alteration of fAHP and AP duration of ACC pyramidal neurons in mCCD rats. The mRNA expression of BKCa β4 subunits was extremely upregulated in the ACC after mCCD with the increased amount of both synaptic and non-synaptic BKCa β4 subunit protein. Meanwhile, NS1619 reversed the enhanced AMPA receptor-mediated spontaneous excitatory postsynaptic current (sEPSC) frequency and the attenuated PPR of ACC neurons in mCCD rats. Local activation of BKCa channels in the ACC reversed mechanical allodynia and anxiety-like behaviors. These results suggest that the upregulation of postsynaptic and presynaptic BKCa β4 subunit may contribute to neuronal hyperexcitability and the enhanced synaptic transmission in the ACC in neuropathic pain state, and then may result in anxiety-like behavior induced by neuropathic pain.
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Affiliation(s)
- Huan Zhao
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China.,Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, China.,Department of Anesthesiology, Heze Municipal Hospital, Heze, 274031, Shandong, China
| | - Qian Xue
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Cong Li
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China.,Department of Anesthesiology, Heze Municipal Hospital, Heze, 274031, Shandong, China.,Shandong First Medcial University & Shandong Academy of Medical Sciences, Taian, 271000, Shandong, China
| | - Qingchuan Wang
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China.,Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, 710072, China
| | - Shichao Han
- Department of Burns and Cutaneous Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Yongsheng Zhou
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Tao Yang
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Yingli Xie
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Hao Fu
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Changbo Lu
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Fancheng Meng
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Ming Zhang
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Yan Zhang
- Department of Anesthesiology, Heze Municipal Hospital, Heze, 274031, Shandong, China
| | - Xianglong Wu
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, 710072, China
| | - Shengxi Wu
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Min Zhuo
- Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, China.,Department of Phsyiology, University of Toronto, Toronto, Canada
| | - Hui Xu
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China. .,Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, China.
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5
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Zhu YR, Jiang XX, Zheng Y, Xiong J, Wei D, Zhang DM. Cardiac function modulation depends on the A-kinase anchoring protein complex. J Cell Mol Med 2019; 23:7170-7179. [PMID: 31512389 PMCID: PMC6815827 DOI: 10.1111/jcmm.14659] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 06/27/2019] [Accepted: 08/06/2019] [Indexed: 12/26/2022] Open
Abstract
The A‐kinase anchoring proteins (AKAPs) are a group of structurally diverse proteins identified in various species and tissues. These proteins are able to anchor protein kinase and other signalling proteins to regulate cardiac function. Acting as a scaffold protein, AKAPs ensure specificity in signal transduction by enzymes close to their appropriate effectors and substrates. Over the decades, more than 70 different AKAPs have been discovered. Accumulative evidence indicates that AKAPs play crucial roles in the functional regulation of cardiac diseases, including cardiac hypertrophy, myofibre contractility dysfunction and arrhythmias. By anchoring different partner proteins (PKA, PKC, PKD and LTCCs), AKAPs take part in different regulatory pathways to function as regulators in the heart, and a damaged structure can influence the activities of these complexes. In this review, we highlight recent advances in AKAP‐associated protein complexes, focusing on local signalling events that are perturbed in cardiac diseases and their roles in interacting with ion channels and their regulatory molecules. These new findings suggest that AKAPs might have potential therapeutic value in patients with cardiac diseases, particularly malignant rhythm.
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Affiliation(s)
- Yan-Rong Zhu
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Xiao-Xin Jiang
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Yaguo Zheng
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Jing Xiong
- Department of Pharmacology, Nanjing Medical University, Nanjing, China
| | - Dongping Wei
- Department of Oncology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Dai-Min Zhang
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
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6
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Kaßmann M, Szijártó IA, García‐Prieto CF, Fan G, Schleifenbaum J, Anistan Y, Tabeling C, Shi Y, le Noble F, Witzenrath M, Huang Y, Markó L, Nelson MT, Gollasch M. Role of Ryanodine Type 2 Receptors in Elementary Ca 2+ Signaling in Arteries and Vascular Adaptive Responses. J Am Heart Assoc 2019; 8:e010090. [PMID: 31030596 PMCID: PMC6512102 DOI: 10.1161/jaha.118.010090] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 02/07/2019] [Indexed: 12/29/2022]
Abstract
Background Hypertension is the major risk factor for cardiovascular disease, the most common cause of death worldwide. Resistance arteries are capable of adapting their diameter independently in response to pressure and flow-associated shear stress. Ryanodine receptors (RyRs) are major Ca2+-release channels in the sarcoplasmic reticulum membrane of myocytes that contribute to the regulation of contractility. Vascular smooth muscle cells exhibit 3 different RyR isoforms (RyR1, RyR2, and RyR3), but the impact of individual RyR isoforms on adaptive vascular responses is largely unknown. Herein, we generated tamoxifen-inducible smooth muscle cell-specific RyR2-deficient mice and tested the hypothesis that vascular smooth muscle cell RyR2s play a specific role in elementary Ca2+ signaling and adaptive vascular responses to vascular pressure and/or flow. Methods and Results Targeted deletion of the Ryr2 gene resulted in a complete loss of sarcoplasmic reticulum-mediated Ca2+-release events and associated Ca2+-activated, large-conductance K+ channel currents in peripheral arteries, leading to increased myogenic tone and systemic blood pressure. In the absence of RyR2, the pulmonary artery pressure response to sustained hypoxia was enhanced, but flow-dependent effects, including blood flow recovery in ischemic hind limbs, were unaffected. Conclusions Our results establish that RyR2-mediated Ca2+-release events in VSCM s specifically regulate myogenic tone (systemic circulation) and arterial adaptation in response to changes in pressure (hypoxic lung model), but not flow. They further suggest that vascular smooth muscle cell-expressed RyR2 deserves scrutiny as a therapeutic target for the treatment of vascular responses in hypertension and chronic vascular diseases.
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Affiliation(s)
- Mario Kaßmann
- Experimental and Clinical Research Centera joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular MedicineCharité–Universitätsmedizin BerlinBerlinGermany
- DZHK (German Centre for Cardiovascular Research), partner site BerlinBerlinGermany
| | - István András Szijártó
- Experimental and Clinical Research Centera joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular MedicineCharité–Universitätsmedizin BerlinBerlinGermany
| | - Concha F. García‐Prieto
- Experimental and Clinical Research Centera joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular MedicineCharité–Universitätsmedizin BerlinBerlinGermany
- Department of Pharmaceutical and Health SciencesFacultad de FarmaciaUniversidad CEU San PabloMadridSpain
| | - Gang Fan
- Experimental and Clinical Research Centera joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular MedicineCharité–Universitätsmedizin BerlinBerlinGermany
| | - Johanna Schleifenbaum
- Experimental and Clinical Research Centera joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular MedicineCharité–Universitätsmedizin BerlinBerlinGermany
| | - Yoland‐Marie Anistan
- Experimental and Clinical Research Centera joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular MedicineCharité–Universitätsmedizin BerlinBerlinGermany
| | - Christoph Tabeling
- Department of Infectious Diseases and Pulmonary MedicineCharité–Universitätsmedizin BerlinBerlinGermany
| | - Yu Shi
- Medical Clinic for Hematology, Oncology and Tumor ImmunologyCharité–Universitätsmedizin BerlinBerlinGermany
| | - Ferdinand le Noble
- Department of Cell and Developmental BiologyITG (Institute of Toxicology and Genetics)Karlsruhe Institute of TechnologyKarlsruheGermany
| | - Martin Witzenrath
- Department of Infectious Diseases and Pulmonary MedicineCharité–Universitätsmedizin BerlinBerlinGermany
| | - Yu Huang
- Institute of Vascular Medicine and School of Biomedical SciencesChinese University of Hong KongChina
| | - Lajos Markó
- Medical Clinic for Hematology, Oncology and Tumor ImmunologyCharité–Universitätsmedizin BerlinBerlinGermany
| | - Mark T. Nelson
- Department of PharmacologyCollege of MedicineThe University of VermontBurlingtonVT
| | - Maik Gollasch
- Experimental and Clinical Research Centera joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular MedicineCharité–Universitätsmedizin BerlinBerlinGermany
- DZHK (German Centre for Cardiovascular Research), partner site BerlinBerlinGermany
- Medical Clinic for Nephrology and Internal Intensive CareCharité–Universitätsmedizin BerlinBerlinGermany
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7
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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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8
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Genetic background dominates the susceptibility to ventricular arrhythmias in a murine model of β-adrenergic stimulation. Sci Rep 2018; 8:2312. [PMID: 29396505 PMCID: PMC5797149 DOI: 10.1038/s41598-018-20792-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 01/24/2018] [Indexed: 11/16/2022] Open
Abstract
In cardiovascular research, several mouse strains with differing genetic backgrounds are used to investigate mechanisms leading to and sustaining ventricular arrhythmias. The genetic background has been shown to affect the studied phenotype in other research fields. Surprisingly little is known about potential strain-specific susceptibilities towards ventricular arrhythmias in vivo. Here, we hypothesized that inter-strain differences reported in the responsiveness of the β-adrenergic pathway, which is relevant for the development of arrhythmias, translate into a strain-specific vulnerability. To test this hypothesis, we characterized responses to β-adrenergic blockade (metoprolol) and β-adrenergic stimulation (isoproterenol) in 4 mouse strains commonly employed in cardiovascular research (Balb/c, BS, C57Bl/6 and FVB) using telemetric ECG recordings. We report pronounced differences in the electrical vulnerability following isoproterenol: Balb/c mice developed the highest number and the most complex arrhythmias while BS mice were protected. Balb/c mice, therefore, seem to be the background of choice for experiments requiring the occurrence of arrhythmias while BS mice may give insight into electrical stability. Arrhythmias did not correlate with the basal β-adrenergic tone, with the response to β-adrenergic stimulation or with the absolute heart rates during β-adrenergic stimulation. Thus, genetic factors dominate the susceptibility to ventricular arrhythmias in this model of β-adrenergic stimulation.
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9
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Zaidman NA, Panoskaltsis-Mortari A, O'Grady SM. Large-conductance Ca 2+ -activated K + channel activation by apical P2Y receptor agonists requires hydrocortisone in differentiated airway epithelium. J Physiol 2017; 595:4631-4645. [PMID: 28481415 DOI: 10.1113/jp274200] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 05/02/2017] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Hydrocortisone (HC) is required for activation of large-conductance Ca2+ -activated K+ current (BK) by purinergic receptor agonists. HC reduces insertion of the stress-regulated exon (STREX) in the KCNMA1 gene, permitting protein kinase C (PKC)-dependent channel activation. Overlapping and unique purinergic signalling regions exist at the apical border of differentiated surface cells. BK channels localize in the cilia of surface cells. ABSTRACT In the present study we investigated the role of hydrocortisone (HC) on uridine-5'-triphosphate (UTP)-stimulated ion transport in differentiated, pseudostratified epithelia derived from normal human bronchial basal cells. The presence of a UTP-stimulated, paxilline-sensitive large-conductance Ca2+ -activated K+ (BK) current was demonstrated in control epithelia but was not stimulated in epithelia differentiated in the absence of HC (HC0). Addition of the BK channel opener NS11021 directly activated channels in control epithelia; however, under HC0 conditions, activation only occurred when UTP was added after NS11021. The PKC inhibitors GF109203x and Gö6983 blocked BK activation by UTP in control epithelia, suggesting that PKC-mediated phosphorylation plays a permissive role in purinoceptor-stimulated BK activation. Moreover, HC0 epithelia expressed significantly more KCNMA1 containing the stress-regulated exon (STREX), a splice-variant of the α-subunit that displays altered channel regulation by phosphorylation, compared to control epithelia. Furthermore, BK channels as well as purinergic receptors were shown to localize in unique and overlapping domains at the apical membrane of ciliated surface cells. These results establish a previously unrecognized role for glucocorticoids in regulation of BK channels in airway epithelial cells.
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Affiliation(s)
- Nathan A Zaidman
- Department of Integrative Biology and Physiology, University of Minnesota, 6-125 Jackson Hall, Minneapolis, MN, USA
| | - Angela Panoskaltsis-Mortari
- Department of Integrative Biology and Physiology, University of Minnesota, 6-125 Jackson Hall, Minneapolis, MN, USA.,Department of Pediatrics, University of Minnesota, 660E MCRB, Minneapolis, MN, USA
| | - Scott M O'Grady
- Department of Integrative Biology and Physiology, University of Minnesota, 6-125 Jackson Hall, Minneapolis, MN, USA.,Department of Animal Science, University of Minnesota, 480 Haecker Hall, St. Paul, Minneapolis, MN, USA
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10
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Hoshi T, Heinemann SH. Modulation of BK Channels by Small Endogenous Molecules and Pharmaceutical Channel Openers. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 128:193-237. [PMID: 27238265 DOI: 10.1016/bs.irn.2016.03.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Voltage- and Ca(2+)-activated K(+) channels of big conductance (BK channels) are abundantly found in various organs and their relevance for smooth muscle tone and neuronal signaling is well documented. Dysfunction of BK channels is implicated in an array of human diseases involving many organs including the nervous, pulmonary, cardiovascular, renal, and urinary systems. In humans a single gene (KCNMA1) encodes the pore-forming α subunit (Slo1) of BK channels, but the channel properties are variable because of alternative splicing, tissue- and subcellular-specific auxiliary subunits (β, γ), posttranslational modifications, and a multitude of endogenous signaling molecules directly affecting the channel function. Initiatives to develop drugs capable of activating BK channels (channel openers) therefore need to consider the tissue-specific variability of BK channel structure and the potential interference with endogenously produced regulatory factors. The atomic structural basis of BK channel function is only beginning to be revealed. However, building on detailed knowledge of BK channel function, including its single-channel characteristics, voltage- and Ca(2+) dependence of channel gating, and modulation by diffusible messengers, a multi-tier allosteric model of BK channel gating (Horrigan and Aldrich (HA) model) has become a valuable tool in studying modulation of the channel. Using the conceptual framework of the HA model, we here review the functional impact of endogenous modulatory factors and select small synthetic compounds that regulate BK channel activity. Furthermore, we devise experimental approaches for studying BK channel-drug interactions with the aim to classify BK-modulating substances according to their molecular mode of action.
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Affiliation(s)
- T Hoshi
- University of Pennsylvania, Philadelphia, PA, United States.
| | - S H Heinemann
- Friedrich Schiller University Jena & Jena University Hospital, Jena, Germany
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BK channel β1-subunit deficiency exacerbates vascular fibrosis and remodelling but does not promote hypertension in high-fat fed obesity in mice. J Hypertens 2016; 33:1611-23. [PMID: 26049174 DOI: 10.1097/hjh.0000000000000590] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Reduced expression or increased degradation of BK (large conductance Ca-activated K) channel β1-subunits has been associated with increased vascular tone and hypertension in some metabolic diseases. The contribution of BK channel function to control of blood pressure (BP), heart rate (HR) and vascular function/structure was determined in wild-type and BK channel β1-subunit knockout mice fed a high-fat or control diet. METHODS AND RESULTS After 24 weeks of high-fat diet, wild-type and BK β1-knockout mice were obese, diabetic, but normotensive. High-fat-BK β1-knockout mice had decreased HR, while high-fat-wild-type mice had increased HR compared with mice on the control diet. Ganglion blockade caused a greater fall in BP and HR in mice on a high-fat diet than in mice on the control diet. β1-adrenergic receptor blockade reduced BP and HR equally in all groups. α1-adrenergic receptor blockade decreased BP in high-fat-BK β1-knockout mice only. Echocardiographic evaluation revealed left ventricular hypertrophy in high-fat-BK β1-knockout mice. Although under anaesthesia, mice on a high-fat diet had higher absolute stroke volume and cardiac output, these measures were similar to control mice when adjusted for body weight. Mesenteric arteries from high-fat-BK β1-knockout mice had higher norepinephrine reactivity, greater wall thickness and collagen accumulation than high-fat-wild-type mesenteric arteries. Compared with control-wild-type mesenteric arteries, high-fat-wild-type mesenteric arteries had blunted contractile responses to a BK channel blocker, although BK α-subunit (protein) and β1-subunit (mRNA) expression were unchanged. CONCLUSION BK channel deficiency promotes increased sympathetic control of BP, and vascular dysfunction, remodelling and fibrosis, but does not cause hypertension in high-fat fed mice.
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Karlin A. Membrane potential and Ca2+ concentration dependence on pressure and vasoactive agents in arterial smooth muscle: A model. ACTA ACUST UNITED AC 2016; 146:79-96. [PMID: 26123196 PMCID: PMC4485026 DOI: 10.1085/jgp.201511380] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A mathematical model incorporating junctional and stretch-activated microdomains and 37 protein components describes the myogenic response in arterial smooth muscle cells. Arterial smooth muscle (SM) cells respond autonomously to changes in intravascular pressure, adjusting tension to maintain vessel diameter. The values of membrane potential (Vm) and sarcoplasmic Ca2+ concentration (Cain) within minutes of a change in pressure are the results of two opposing pathways, both of which use Ca2+ as a signal. This works because the two Ca2+-signaling pathways are confined to distinct microdomains in which the Ca2+ concentrations needed to activate key channels are transiently higher than Cain. A mathematical model of an isolated arterial SM cell is presented that incorporates the two types of microdomains. The first type consists of junctions between cisternae of the peripheral sarcoplasmic reticulum (SR), containing ryanodine receptors (RyRs), and the sarcolemma, containing voltage- and Ca2+-activated K+ (BK) channels. These junctional microdomains promote hyperpolarization, reduced Cain, and relaxation. The second type is postulated to form around stretch-activated nonspecific cation channels and neighboring Ca2+-activated Cl− channels, and promotes the opposite (depolarization, increased Cain, and contraction). The model includes three additional compartments: the sarcoplasm, the central SR lumen, and the peripheral SR lumen. It incorporates 37 protein components. In addition to pressure, the model accommodates inputs of α- and β-adrenergic agonists, ATP, 11,12-epoxyeicosatrienoic acid, and nitric oxide (NO). The parameters of the equations were adjusted to obtain a close fit to reported Vm and Cain as functions of pressure, which have been determined in cerebral arteries. The simulations were insensitive to ±10% changes in most of the parameters. The model also simulated the effects of inhibiting RyR, BK, or voltage-activated Ca2+ channels on Vm and Cain. Deletion of BK β1 subunits is known to increase arterial–SM tension. In the model, deletion of β1 raised Cain at all pressures, and these increases were reversed by NO.
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Affiliation(s)
- Arthur Karlin
- Department of Biochemistry and Molecular Biophysics, Department of Physiology and Cellular Biophysics, and Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY 10032
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Larsen CK, Jensen IS, Sorensen MV, de Bruijn PI, Bleich M, Praetorius HA, Leipziger J. Hyperaldosteronism after decreased renal K+ excretion in KCNMB2 knockout mice. Am J Physiol Renal Physiol 2016; 310:F1035-46. [PMID: 26962098 DOI: 10.1152/ajprenal.00010.2016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 03/08/2016] [Indexed: 11/22/2022] Open
Abstract
The kidney is the primary organ ensuring K(+) homeostasis. K(+) is secreted into the urine in the distal tubule by two mechanisms: by the renal outer medullary K(+) channel (Kir1.1) and by the Ca(2+)-activated K(+) channel (KCa1.1). Here, we report a novel knockout mouse of the β2-subunit of the KCa1.1 channel (KCNMB2), which displays hyperaldosteronism after decreased renal K(+) excretion. KCNMB2(-/-) mice displayed hyperaldosteronism, normal plasma K(+) concentration, and produced dilute urine with decreased K(+) concentration. The normokalemia indicated that hyperaldosteronism did not result from primary aldosteronism. Activation of the renin-angiotensin-aldosterone system was also ruled out as renal renin mRNA expression was reduced in KCNMB2(-/-) mice. Renal K(+) excretion rates were similar in the two genotypes; however, KCNMB2(-/-) mice required elevated plasma aldosterone to achieve K(+) balance. Blockade of the mineralocorticoid receptor with eplerenone triggered mild hyperkalemia and unmasked reduced renal K(+) excretion in KCNMB2(-/-) mice. Knockout mice for the α-subunit of the KCa1.1 channel (KCNMA1(-/-) mice) have hyperaldosteronism, are hypertensive, and lack flow-induced K(+) secretion. KCNMB2(-/-) mice share the phenotypic traits of normokalemia and hyperaldosteronism with KCNMA1(-/-) mice but were normotensive and displayed intact flow-induced K(+) secretion. Despite elevated plasma aldosterone, KNCMB2(-/-) mice did not display salt-sensitive hypertension and were able to decrease plasma aldosterone on a high-Na(+) diet, although plasma aldosterone remained elevated in KCNMB2(-/-) mice. In summary, KCNMB2(-/-) mice have a reduced ability to excrete K(+) into the urine but achieve K(+) balance through an aldosterone-mediated, β2-independent mechanism. The phenotype of KCNMB2 mice was similar but milder than the phenotype of KCNMA1(-/-) mice.
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Affiliation(s)
- Casper K Larsen
- Department of Biomedicine, Physiology, and Health, Aarhus University, Aarhus, Denmark
| | - Iben S Jensen
- Department of Biomedicine, Physiology, and Health, Aarhus University, Aarhus, Denmark
| | - Mads V Sorensen
- Department of Biomedicine, Physiology, and Health, Aarhus University, Aarhus, Denmark; Aarhus Institute for Advanced Studies, Aarhus University, Aarhus, Denmark; and
| | - Pauline I de Bruijn
- Department of Biomedicine, Physiology, and Health, Aarhus University, Aarhus, Denmark
| | - Markus Bleich
- Institute of Physiology, Christian-Albrechts-University, Kiel, Germany
| | - Helle A Praetorius
- Department of Biomedicine, Physiology, and Health, Aarhus University, Aarhus, Denmark
| | - Jens Leipziger
- Department of Biomedicine, Physiology, and Health, Aarhus University, Aarhus, Denmark;
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Pratt CP, He J, Wang Y, Barth AL, Bruchez MP. Fluorogenic Green-Inside Red-Outside (GIRO) Labeling Approach Reveals Adenylyl Cyclase-Dependent Control of BKα Surface Expression. Bioconjug Chem 2015; 26:1963-71. [PMID: 26301573 PMCID: PMC4576318 DOI: 10.1021/acs.bioconjchem.5b00409] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
The
regulation of surface levels of protein is critical for proper
cell function and influences properties including cell adhesion, ion
channel contributions to current flux, and the sensitivity of surface
receptors to ligands. Here we demonstrate a two-color labeling system
in live cells using a single fluorogen activating peptide (FAP) based
fusion tag, which enables the rapid and simultaneous quantification
of surface and internal proteins. In the nervous system, BK channels
can regulate neural excitability and neurotransmitter release, and
the surface trafficking of BK channels can be modulated by signaling
cascades and assembly with accessory proteins. Using this labeling
approach, we examine the dynamics of BK channel surface expression
in HEK293 cells. Surface pools of the pore-forming BKα subunit
were stable, exhibiting a plasma membrane half-life of >10 h. Long-term
activation of adenylyl cyclase by forskolin reduced BKα surface
levels by 30%, an effect that could not be attributed to increased
bulk endocytosis of plasma membrane proteins. This labeling approach
is compatible with microscopic imaging and flow cytometry, providing
a solid platform for examining protein trafficking in living cells.
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Affiliation(s)
- Christopher P Pratt
- Department of Biological Sciences, ‡Department of Chemistry, §Molecular Biosensor and Imaging Center, and #Center for the Neural Basis of Cognition, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Jianjun He
- Department of Biological Sciences, ‡Department of Chemistry, §Molecular Biosensor and Imaging Center, and #Center for the Neural Basis of Cognition, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Yi Wang
- Department of Biological Sciences, ‡Department of Chemistry, §Molecular Biosensor and Imaging Center, and #Center for the Neural Basis of Cognition, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Alison L Barth
- Department of Biological Sciences, ‡Department of Chemistry, §Molecular Biosensor and Imaging Center, and #Center for the Neural Basis of Cognition, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Marcel P Bruchez
- Department of Biological Sciences, ‡Department of Chemistry, §Molecular Biosensor and Imaging Center, and #Center for the Neural Basis of Cognition, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
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15
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Penton D, Czogalla J, Loffing J. Dietary potassium and the renal control of salt balance and blood pressure. Pflugers Arch 2015; 467:513-30. [PMID: 25559844 DOI: 10.1007/s00424-014-1673-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 12/10/2014] [Accepted: 12/11/2014] [Indexed: 01/09/2023]
Abstract
Dietary potassium (K(+)) intake has antihypertensive effects, prevents strokes, and improves cardiovascular outcomes. The underlying mechanism for these beneficial effects of high K(+) diets may include vasodilation, enhanced urine flow, reduced renal renin release, and negative sodium (Na(+)) balance. Indeed, several studies demonstrate that dietary K(+) intake induces renal Na(+) loss despite elevated plasma aldosterone. This review briefly highlights the epidemiological and experimental evidences for the effects of dietary K(+) on arterial blood pressure. It discusses the pivotal role of the renal distal tubule for the regulation of urinary K(+) and Na(+) excretion and blood pressure and highlights that it depends on the coordinated interaction of different nephron portions, epithelial cell types, and various ion channels, transporters, and ATPases. Moreover, we discuss the relevance of aldosterone and aldosterone-independent factors in mediating the effects of an altered K(+) intake on renal K(+) and Na(+) handling. Particular focus is given to findings suggesting that an aldosterone-independent downregulation of the thiazide-sensitive NaCl cotransporter significantly contributes to the natriuretic and antihypertensive effect of a K(+)-rich diet. Last but not least, we refer to the complex signaling pathways enabling the kidney to adapt its function to the homeostatic needs in response to an altered K(+) intake. Future work will have to further address the underlying cellular and molecular mechanism and to elucidate, among others, how an altered dietary K(+) intake is sensed and how this signal is transmitted to the different epithelial cells lining the distal tubule.
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Affiliation(s)
- David Penton
- Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
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