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Ca 2+-Activated K + Channels and the Regulation of the Uteroplacental Circulation. Int J Mol Sci 2023; 24:ijms24021349. [PMID: 36674858 PMCID: PMC9867535 DOI: 10.3390/ijms24021349] [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: 12/14/2022] [Revised: 01/06/2023] [Accepted: 01/08/2023] [Indexed: 01/13/2023] Open
Abstract
Adequate uteroplacental blood supply is essential for the development and growth of the placenta and fetus during pregnancy. Aberrant uteroplacental perfusion is associated with pregnancy complications such as preeclampsia, fetal growth restriction (FGR), and gestational diabetes. The regulation of uteroplacental blood flow is thus vital to the well-being of the mother and fetus. Ca2+-activated K+ (KCa) channels of small, intermediate, and large conductance participate in setting and regulating the resting membrane potential of vascular smooth muscle cells (VSMCs) and endothelial cells (ECs) and play a critical role in controlling vascular tone and blood pressure. KCa channels are important mediators of estrogen/pregnancy-induced adaptive changes in the uteroplacental circulation. Activation of the channels hyperpolarizes uteroplacental VSMCs/ECs, leading to attenuated vascular tone, blunted vasopressor responses, and increased uteroplacental blood flow. However, the regulation of uteroplacental vascular function by KCa channels is compromised in pregnancy complications. This review intends to provide a comprehensive overview of roles of KCa channels in the regulation of the uteroplacental circulation under physiological and pathophysiological conditions.
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Jia X, Chen X, Gao C, Wang H, Yang C, Jiang LH, Fan Y. Functional cooperation between IK Ca and TRPC1 channels regulates serum-induced vascular smooth muscle cell proliferation via mediating Ca 2+ influx and ERK1/2 activation. Cell Prolif 2022; 56:e13385. [PMID: 36562293 PMCID: PMC10068941 DOI: 10.1111/cpr.13385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 12/06/2022] [Accepted: 12/08/2022] [Indexed: 12/24/2022] Open
Abstract
The increased proliferation of vascular smooth muscle cells (VSMCs) contributes to the pathogenesis of vascular diseases. The intermediate conductance calcium-activated potassium (IKCa ) channel plays a critical role in VSMC proliferation by raising the intracellular calcium concentration ([Ca2+ ]i ), but the underlying mechanism is still not unclear. Here we investigated the cooperation between IKCa and transient receptor potential canonical 1 (TRPC1) channels in mediating extracellular Ca2+ entry, which in turn activates downstream Ca2+ signalling in the regulation of VSMC proliferation using serum-induced cell proliferation model. Serum-induced cell proliferation was accompanied with up-regulation of IKCa expression and an increase in [Ca2+ ]i . Serum-induced cell proliferation and increase in [Ca2+ ]i were suppressed by IKCa inhibition with TRAM-34 or IKCa knockdown. Serum-induced cell proliferation was strongly reduced by the removal of extracellular Ca2+ with EGTA or intracellular Ca2+ with BAPTA-AM and, additionally, by TRPC1 knockdown. Moreover, the increase in [Ca2+ ]i induced by serum or by IKCa activation with 1-EBIO was attenuated by TRPC1 knockdown. Finally, serum induced ERK1/2 activation, which was attenuated by treatment with TRAM-34 or BAPTA-AM, as well as TRPC1 knockdown. Consistently, serum-induced cell proliferation was suppressed by ERK1/2 inhibition with PD98059. Taken together, these results suggest that the IKCa and TRPC1 channels cooperate in mediating Ca2+ influx that activates the ERK1/2 pathway to promote cell proliferation, thus providing new mechanistic insights into VSMC proliferation.
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Affiliation(s)
- Xiaoling Jia
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, China
| | - Xinlan Chen
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, China
| | - Chao Gao
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, China
| | - Haikun Wang
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, China
| | - Chengxi Yang
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, China
| | - Lin-Hua Jiang
- Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, and Department of Physiology and Pathophysiology, Xinxiang Medical University, Xinxiang, China.,A4245-Transplantation, Immunology and Inflammation, Faculty of Medicine, University of Tours, Tours, France.,School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Yubo Fan
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, China
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3
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Jia X, Yang Q, Gao C, Chen X, Li Y, Su H, Zheng Y, Zhang S, Wang Z, Wang H, Jiang LH, Sun Y, Fan Y. Stimulation of vascular smooth muscle cell proliferation by stiff matrix via the IK Ca channel-dependent Ca 2+ signaling. J Cell Physiol 2021; 236:6897-6906. [PMID: 33650160 DOI: 10.1002/jcp.30349] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 02/14/2021] [Accepted: 02/16/2021] [Indexed: 12/13/2022]
Abstract
Vascular stiffening, an early and common characteristic of cardiovascular diseases (CVDs), stimulates vascular smooth muscle cell (VSMC) proliferation which reciprocally accelerates the progression of CVDs. However, the mechanisms by which extracellular matrix stiffness accompanying vascular stiffening regulates VSMC proliferation remain largely unknown. In the present study, we examined the role of the intermediate-conductance Ca2+ -activated K+ (IKCa ) channel in the matrix stiffness regulation of VSMC proliferation by growing A7r5 cells on soft and stiff polydimethylsiloxane substrates with stiffness close to these of arteries under physiological and pathological conditions, respectively. Stiff substrates stimulated cell proliferation and upregulated the expression of the IKCa channel. Stiff substrate-induced cell proliferation was suppressed by pharmacological inhibition using TRAM34, an IKCa channel blocker, or genetic depletion of the IKCa channel. In addition, stiff substrate-induced cell proliferation was also suppressed by reducing extracellular Ca2+ concentration using EGTA or intracellular Ca2+ concentration using BAPTA-AM. Moreover, stiff substrate induced activation of extracellular signal-regulated kinases (ERKs), which was inhibited by treatment with TRAM34 or BAPTA-AM. Stiff substrate-induced cell proliferation was suppressed by treatment with PD98059, an ERK inhibitor. Taken together, these results show that substrates with pathologically relevant stiffness upregulate the IKCa channel expression to enhance intracellular Ca2+ signaling and subsequent activation of the ERK signal pathway to drive cell proliferation. These findings provide a novel mechanism by which vascular stiffening regulates VSMC function.
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Affiliation(s)
- Xiaoling Jia
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.,School of Engineering Medicine, Beihang University, No.37, Xueyuan Road, haidian district, Beijing, China.,School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Qingmao Yang
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.,School of Engineering Medicine, Beihang University, No.37, Xueyuan Road, haidian district, Beijing, China
| | - Chao Gao
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.,School of Engineering Medicine, Beihang University, No.37, Xueyuan Road, haidian district, Beijing, China
| | - Xinlan Chen
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.,School of Engineering Medicine, Beihang University, No.37, Xueyuan Road, haidian district, Beijing, China
| | - Yanan Li
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.,School of Engineering Medicine, Beihang University, No.37, Xueyuan Road, haidian district, Beijing, China
| | - Hao Su
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.,School of Engineering Medicine, Beihang University, No.37, Xueyuan Road, haidian district, Beijing, China
| | - Yufan Zheng
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.,School of Engineering Medicine, Beihang University, No.37, Xueyuan Road, haidian district, Beijing, China
| | - Shuwen Zhang
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.,School of Engineering Medicine, Beihang University, No.37, Xueyuan Road, haidian district, Beijing, China
| | - Ziyu Wang
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.,School of Engineering Medicine, Beihang University, No.37, Xueyuan Road, haidian district, Beijing, China
| | - Haikun Wang
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.,School of Engineering Medicine, Beihang University, No.37, Xueyuan Road, haidian district, Beijing, China
| | - Lin-Hua Jiang
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK.,Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province and Department of Physiology and Pathophysiology, Xinxiang Medical University, Xinxiang, China
| | - Yan Sun
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.,School of Engineering Medicine, Beihang University, No.37, Xueyuan Road, haidian district, Beijing, China
| | - Yubo Fan
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.,School of Engineering Medicine, Beihang University, No.37, Xueyuan Road, haidian district, Beijing, China
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Jia X, Su H, Chen X, Huang Y, Zheng Y, Ji P, Gao C, Gong X, Huang Y, Jiang LH, Fan Y. A critical role of the K Ca 3.1 channel in mechanical stretch-induced proliferation of rat bone marrow-derived mesenchymal stem cells. J Cell Mol Med 2020; 24:3739-3744. [PMID: 32065503 PMCID: PMC7131943 DOI: 10.1111/jcmm.15014] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 01/02/2020] [Accepted: 01/06/2020] [Indexed: 12/11/2022] Open
Abstract
Mechanical stimulation is an important factor regulating mesenchymal stem cell (MSC) functions such as proliferation. The Ca2+ -activated K+ channel, KCa 3.1, is critically engaged in MSC proliferation but its role in mechanical regulation of MSC proliferation remains unknown. Here, we examined the KCa 3.1 channel expression and its role in rat bone marrow-derived MSC (BMSC) proliferation in response to mechanical stretch. Application of mechanical stretch stimulated BMSC proliferation via promoting cell cycle progression. Such mechanical stimulation up-regulated the KCa 3.1 channel expression and pharmacological or genetic inhibition of the KCa 3.1 channel strongly suppressed stretch-induced increase in cell proliferation and cell cycle progression. These results support that the KCa 3.1 channel plays an important role in transducing mechanical forces to MSC proliferation. Our finding provides new mechanistic insights into how mechanical stimuli regulate MSC proliferation and also a viable bioengineering approach to improve MSC proliferation.
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Affiliation(s)
- Xiaoling Jia
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.,Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University, Beijing, China.,School of Biomedical Science, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Hao Su
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Xinlan Chen
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Yangbi Huang
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Yufan Zheng
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Pei Ji
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Chao Gao
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Xianghui Gong
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Yan Huang
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Lin-Hua Jiang
- School of Biomedical Science, Faculty of Biological Sciences, University of Leeds, Leeds, UK.,Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, China
| | - Yubo Fan
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.,Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University, Beijing, China.,Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, National Research Center for Rehabilitation Technical Aids, Beijing, China
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Roach KM, Bradding P. Ca 2+ signalling in fibroblasts and the therapeutic potential of K Ca3.1 channel blockers in fibrotic diseases. Br J Pharmacol 2020; 177:1003-1024. [PMID: 31758702 DOI: 10.1111/bph.14939] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 10/23/2019] [Accepted: 11/13/2019] [Indexed: 12/13/2022] Open
Abstract
The role of Ca2+ signalling in fibroblasts is of great interest in fibrosis-related diseases. Intracellular free Ca2+ ([Ca2+ ]i ) is a ubiquitous secondary messenger, regulating a number of cellular functions such as secretion, metabolism, differentiation, proliferation and contraction. The intermediate conductance Ca2+ -activated K+ channel KCa 3.1 is pivotal in Ca2+ signalling and plays a central role in fibroblast processes including cell activation, migration and proliferation through the regulation of cell membrane potential. Evidence from a number of approaches demonstrates that KCa 3.1 plays an important role in the development of many fibrotic diseases, including idiopathic pulmonary, renal tubulointerstitial fibrosis and cardiovascular disease. The KCa 3.1 selective blocker senicapoc was well tolerated in clinical trials for sickle cell disease, raising the possibility of rapid translation to the clinic for people suffering from pathological fibrosis. This review after analysing all the data, concludes that targeting KCa 3.1 should be a high priority for human fibrotic disease.
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Affiliation(s)
- Katy M Roach
- Institute for Lung Health, Department of Respiratory Sciences, University of Leicester, Leicester, UK
| | - Peter Bradding
- Institute for Lung Health, Department of Respiratory Sciences, University of Leicester, Leicester, UK
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6
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Critical regulation of atherosclerosis by the KCa3.1 channel and the retargeting of this therapeutic target in in-stent neoatherosclerosis. J Mol Med (Berl) 2019; 97:1219-1229. [DOI: 10.1007/s00109-019-01814-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 05/07/2019] [Accepted: 06/18/2019] [Indexed: 01/09/2023]
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López-López JR, Cidad P, Pérez-García MT. Kv channels and vascular smooth muscle cell proliferation. Microcirculation 2018; 25. [PMID: 29110368 DOI: 10.1111/micc.12427] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 10/30/2017] [Indexed: 12/12/2022]
Abstract
Kv channels are present in virtually all VSMCs and strongly influence contractile responses. However, they are also instrumental in the proliferative, migratory, and secretory functions of synthetic, dedifferentiated VSMCs upon PM. In fact, Kv channels not only contribute to all these processes but also are active players in the phenotypic switch itself. This review is focused on the role(s) of Kv channels in VSMC proliferation, which is one of the best characterized functions of dedifferentiated VSMCs. VSMC proliferation is a complex process requiring specific Kv channels at specific time and locations. Their identification is further complicated by their large diversity and the differences in expression across vascular beds. Of interest, both conserved changes in some Kv channels and vascular bed-specific regulation of others seem to coexist and participate in VSMC proliferation through complementary mechanisms. Such a system will add flexibility to the process while providing the required robustness to preserve this fundamental cellular response.
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Affiliation(s)
- José R López-López
- Departamento de Bioquímica y Biología Molecular y Fisiología e Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid y Consejo Superior de Investigaciones Científicas (CSIC), Valladolid, Spain
| | - Pilar Cidad
- Departamento de Bioquímica y Biología Molecular y Fisiología e Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid y Consejo Superior de Investigaciones Científicas (CSIC), Valladolid, Spain
| | - M Teresa Pérez-García
- Departamento de Bioquímica y Biología Molecular y Fisiología e Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid y Consejo Superior de Investigaciones Científicas (CSIC), Valladolid, Spain
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Anumanthan G, Gupta S, Fink MK, Hesemann NP, Bowles DK, McDaniel LM, Muhammad M, Mohan RR. KCa3.1 ion channel: A novel therapeutic target for corneal fibrosis. PLoS One 2018; 13:e0192145. [PMID: 29554088 PMCID: PMC5858751 DOI: 10.1371/journal.pone.0192145] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 01/17/2018] [Indexed: 12/16/2022] Open
Abstract
Vision impairment from corneal fibrosis is a common consequence of irregular corneal wound healing after injury. Intermediate-conductance calmodulin/calcium-activated K+ channels 3.1 (KCa3.1) play an important role in cell cycle progression and cellular proliferation. Proliferation and differentiation of corneal fibroblasts to myofibroblasts can lead to corneal fibrosis after injury. KCa3.1 has been shown in many non-ocular tissues to promote fibrosis, but its role in corneal fibrosis is still unknown. In this study, we characterized the expression KCa3.1 in the human cornea and its role in corneal wound healing in vivo using a KCa3.1 knockout (KCa3.1-/-) mouse model. Additionally, we tested the hypothesis that blockade of KCa3.1 by a selective KCa3.1 inhibitor, TRAM-34, could augment a novel interventional approach for controlling corneal fibrosis in our established in vitro model of corneal fibrosis. The expression of KCa3.1 gene and protein was analyzed in human and murine corneas. Primary human corneal fibroblast (HCF) cultures were used to examine the potential of TRAM-34 in treating corneal fibrosis by measuring levels of pro-fibrotic genes, proteins, and cellular migration using real-time quantitative qPCR, Western blotting, and scratch assay, respectively. Cytotoxicity of TRAM-34 was tested with trypan blue assay, and pro-fibrotic marker expression was tested in KCa3.1-/-. Expression of KCa3.1 mRNA and protein was detected in all three layers of the human cornea. The KCa3.1-/- mice demonstrated significantly reduced corneal fibrosis and expression of pro-fibrotic marker genes such as collagen I and α-smooth muscle actin (α-SMA), suggesting that KCa3.1 plays an important role corneal wound healing in vivo. Pharmacological treatment with TRAM-34 significantly attenuated corneal fibrosis in vitro, as demonstrated in HCFs by the inhibition TGFβ-mediated transcription of pro-fibrotic collagen I mRNA and α-SMA mRNA and protein expression (p<0.001). No evidence of cytotoxicity was observed. Our study suggests that KCa3.1 regulates corneal wound healing and that blockade of KCa3.1 by TRAM-34 offers a potential therapeutic strategy for developing therapies to cure corneal fibrosis in vivo.
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Affiliation(s)
- Govindaraj Anumanthan
- Harry S. Truman Memorial Veteran Hospital, Columbia, Missouri, United States of America
- Veterinary Medicine and Surgery, University of Missouri, Columbia, Missouri, United States of America
| | - Suneel Gupta
- Harry S. Truman Memorial Veteran Hospital, Columbia, Missouri, United States of America
- Veterinary Medicine and Surgery, University of Missouri, Columbia, Missouri, United States of America
| | - Michael K. Fink
- Harry S. Truman Memorial Veteran Hospital, Columbia, Missouri, United States of America
- Veterinary Medicine and Surgery, University of Missouri, Columbia, Missouri, United States of America
| | - Nathan P. Hesemann
- Harry S. Truman Memorial Veteran Hospital, Columbia, Missouri, United States of America
- Mason Eye Institute, University of Missouri School of Medicine, Columbia, Missouri, United States of America
| | - Douglas K. Bowles
- Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States of America
| | - Lindsey M. McDaniel
- Harry S. Truman Memorial Veteran Hospital, Columbia, Missouri, United States of America
- Mason Eye Institute, University of Missouri School of Medicine, Columbia, Missouri, United States of America
| | - Maaz Muhammad
- Veterinary Medicine and Surgery, University of Missouri, Columbia, Missouri, United States of America
| | - Rajiv R. Mohan
- Harry S. Truman Memorial Veteran Hospital, Columbia, Missouri, United States of America
- Veterinary Medicine and Surgery, University of Missouri, Columbia, Missouri, United States of America
- Mason Eye Institute, University of Missouri School of Medicine, Columbia, Missouri, United States of America
- Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States of America
- * E-mail:
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Liu L, Zhan P, Nie D, Fan L, Lin H, Gao L, Mao X. Intermediate-Conductance-Ca2-Activated K Channel IKCa1 Is Upregulated and Promotes Cell Proliferation in Cervical Cancer. Med Sci Monit Basic Res 2017; 23:45-57. [PMID: 28280257 PMCID: PMC5358865 DOI: 10.12659/msmbr.901462] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 12/20/2016] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Accumulating data point to intermediate-conductance calcium-activated potassium channel (IKCa1) as a key player in controlling cell cycle progression and proliferation of human cancer cells. However, the role that IKCa1 plays in the growth of human cervical cancer cells is largely unexplored. MATERIAL AND METHODS In this study, Western blot analysis, immunohistochemical staining, and RT-PCR were first used for IKCa1protein and gene expression assays in cervical cancer tissues and HeLa cells. Then, IKCa1 channel blocker and siRNA were employed to inhibit the functionality of IKCa1 and downregulate gene expression in HeLa cells, respectively. After these treatments, we examined the level of cell proliferation by MTT method and measured IKCa1 currents by conventional whole-cell patch clamp technique. Cell apoptosis was assessed using the Annexin V-FITC/Propidium Iodide (PI) double-staining apoptosis detection kit. RESULTS We demonstrated that IKCa1 mRNA and protein are preferentially expressed in cervical cancer tissues and HeLa cells. We also showed that the IKCa1 channel blocker, clotrimazole, and IKCa1 channel siRNA can be used to suppress cervical cancer cell proliferation and decrease IKCa1 channel current. IKCa1 downregulation by specific siRNAs induced a significant increase in the proportion of apoptotic cells in HeLa cells. CONCLUSIONS IKCa1 is overexpressed in cervical cancer tissues, and IKCa1 upregulation in cervical cancer cell linea enhances cell proliferation, partly by reducing the proportion of apoptotic cells.
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Affiliation(s)
| | | | | | | | | | | | - Xiguang Mao
- Corresponding Authors: Xiguang Mao, e-mail: ; Lanyang Gao, e-mail:
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Köhler R, Oliván-Viguera A, Wulff H. Endothelial Small- and Intermediate-Conductance K Channels and Endothelium-Dependent Hyperpolarization as Drug Targets in Cardiovascular Disease. ADVANCES IN PHARMACOLOGY 2016; 77:65-104. [DOI: 10.1016/bs.apha.2016.04.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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11
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Rabjerg M, Oliván-Viguera A, Hansen LK, Jensen L, Sevelsted-Møller L, Walter S, Jensen BL, Marcussen N, Köhler R. High expression of KCa3.1 in patients with clear cell renal carcinoma predicts high metastatic risk and poor survival. PLoS One 2015; 10:e0122992. [PMID: 25848765 PMCID: PMC4388734 DOI: 10.1371/journal.pone.0122992] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 02/26/2015] [Indexed: 01/08/2023] Open
Abstract
Background Ca2+-activated K+ channels have been implicated in cancer cell growth, metastasis, and tumor angiogenesis. Here we hypothesized that high mRNA and protein expression of the intermediate-conductance Ca2+-activated K+ channel, KCa3.1, is a molecular marker of clear cell Renal Cell Carcinoma (ccRCC) and metastatic potential and survival. Methodology/Principal Findings We analyzed channel expression by qRT-PCR, immunohistochemistry, and patch-clamp in ccRCC and benign oncocytoma specimens, in primary ccRCC and oncocytoma cell lines, as well as in two ccRCC cell lines (Caki-1 and Caki-2). CcRCC specimens contained 12-fold higher mRNA levels of KCa3.1 than oncocytoma specimens. The large-conductance channel, KCa1.1, was 3-fold more highly expressed in ccRCC than in oncocytoma. KCa3.1 mRNA expression in ccRCC was 2-fold higher than in the healthy cortex of the same kidney. Disease specific survival trended towards reduction in the subgroup of high-KCa3.1-expressing tumors (p<0.08 vs. low-KCa3.1-expressing tumors). Progression-free survival (time to metastasis/recurrence) was reduced significantly in the subgroup of high-KCa3.1-expressing tumors (p<0.02, vs. low-KCa3.1-expressing tumors). Immunohistochemistry revealed high protein expression of KCa3.1 in tumor vessels of ccRCC and oncocytoma and in a subset of ccRCC cells. Oncocytoma cells were devoid of KCa3.1 protein. In a primary ccRCC cell line and Caki-1/2-ccRCC cells, we found KCa3.1-protein as well as TRAM-34-sensitive KCa3.1-currents in a subset of cells. Furthermore, Caki-1/2-ccRCC cells displayed functional Paxilline-sensitive KCa1.1 currents. Neither KCa3.1 nor KCa1.1 were found in a primary oncocytoma cell line. Yet KCa-blockers, like TRAM-34 (KCa3.1) and Paxilline (KCa1.1), had no appreciable effects on Caki-1 proliferation in-vitro. Conclusions/Significance Our study demonstrated expression of KCa3.1 in ccRCC but not in benign oncocytoma. Moreover, high KCa3.1-mRNA expression levels were indicative of low disease specific survival of ccRCC patients, short progression-free survival, and a high metastatic potential. Therefore, KCa3.1 is of prognostic value in ccRCC.
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Affiliation(s)
- Maj Rabjerg
- Department of Pathology, Odense University Hospital, DK-5000 Odense C, Denmark
- * E-mail:
| | | | - Lars Koch Hansen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, DK-5000 Odense C, Denmark
| | - Line Jensen
- Department of Pathology, Odense University Hospital, DK-5000 Odense C, Denmark
| | - Linda Sevelsted-Møller
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, DK-5000 Odense C, Denmark
| | - Steen Walter
- Department of Urology, Odense University Hospital, DK-5000 Odense C, Denmark
| | - Boye L. Jensen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, DK-5000 Odense C, Denmark
| | - Niels Marcussen
- Department of Pathology, Odense University Hospital, DK-5000 Odense C, Denmark
| | - Ralf Köhler
- Aragon Institute of Health Sciences I+CS/IIS, 50009 Zaragoza, Spain
- Fundación Agencia Aragonesa para la Investigación y Desarrollo (ARAID), 50009 Zaragoza, Spain
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12
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Intermediate conductance, Ca2+-activated K+ channels: a novel target for chronic renal diseases. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s11515-014-1339-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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13
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Kacik M, Oliván-Viguera A, Köhler R. Modulation of K(Ca)3.1 channels by eicosanoids, omega-3 fatty acids, and molecular determinants. PLoS One 2014; 9:e112081. [PMID: 25372486 PMCID: PMC4221270 DOI: 10.1371/journal.pone.0112081] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 10/12/2014] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Cytochrome P450- and ω-hydrolase products (epoxyeicosatrienoic acids (EETs), hydroxyeicosatetraeonic acid (20-HETE)), natural omega-3 fatty acids (ω3), and pentacyclic triterpenes have been proposed to contribute to a wide range of vaso-protective and anti-fibrotic/anti-cancer signaling pathways including the modulation of membrane ion channels. Here we studied the modulation of intermediate-conductance Ca(2+)/calmodulin-regulated K(+) channels (K(Ca)3.1) by EETs, 20-HETE, ω3, and pentacyclic triterpenes and the structural requirements of these fatty acids to exert channel blockade. METHODOLOGY/PRINCIPAL FINDINGS We studied modulation of cloned human hK(Ca)3.1 and the mutant hK(Ca)3.1(V275A) in HEK-293 cells, of rK(Ca)3.1 in aortic endothelial cells, and of mK(Ca)3.1 in 3T3-fibroblasts by inside-out and whole-cell patch-clamp experiments, respectively. In inside-out patches, Ca(2+)-activated hK(Ca)3.1 were inhibited by the ω3, DHA and α-LA, and the ω6, AA, in the lower µmolar range and with similar potencies. 5,6-EET, 8,9-EET, 5,6-DiHETE, and saturated arachidic acid, had no appreciable effects. In contrast, 14,15-EET, its stable derivative, 14,15-EEZE, and 20-HETE produced channel inhibition. 11,12-EET displayed less inhibitory activity. The K(Ca)3.1(V275A) mutant channel was insensitive to any of the blocking EETs. Non-blocking 5,6-EET antagonized the inhibition caused by AA and augmented cloned hK(Ca)3.1 and rK(Ca)3.1 whole-cell currents. Pentacyclic triterpenes did not modulate K(Ca)3.1 currents. CONCLUSIONS/SIGNIFICANCE Inhibition of K(Ca)3.1 by EETs (14,15-EET), 20-HETE, and ω3 critically depended on the presence of electron double bonds and hydrophobicity within the 10 carbons preceding the carboxyl-head of the molecules. From the physiological perspective, metabolism of AA to non-blocking 5,6,- and 8,9-EET may cause AA-de-blockade and contribute to cellular signal transduction processes influenced by these fatty acids.
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Affiliation(s)
- Michael Kacik
- Faculty of Medicine, Philipps-University Marburg & Medical Center I, Clemenshospital/University Hospital of University Münster, 48153 Münster, Germany
| | | | - Ralf Köhler
- Aragon Institute of Health Sciences I+CS/IIS, 50009 Zaragoza, Spain
- Fundación Agencia Aragonesa para la Investigación y Desarrollo (ARAID), 50018 Zaragoza, Spain
- * E-mail:
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14
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Cidad P, Miguel-Velado E, Ruiz-McDavitt C, Alonso E, Jiménez-Pérez L, Asuaje A, Carmona Y, García-Arribas D, López J, Marroquín Y, Fernández M, Roqué M, Pérez-García MT, López-López JR. Kv1.3 channels modulate human vascular smooth muscle cells proliferation independently of mTOR signaling pathway. Pflugers Arch 2014; 467:1711-22. [PMID: 25208915 DOI: 10.1007/s00424-014-1607-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 08/07/2014] [Accepted: 09/01/2014] [Indexed: 01/25/2023]
Abstract
Phenotypic modulation (PM) of vascular smooth muscle cells (VSMCs) is central to the process of intimal hyperplasia which constitutes a common pathological lesion in occlusive vascular diseases. Changes in the functional expression of Kv1.5 and Kv1.3 currents upon PM in mice VSMCs have been found to contribute to cell migration and proliferation. Using human VSMCs from vessels in which unwanted remodeling is a relevant clinical complication, we explored the contribution of the Kv1.5 to Kv1.3 switch to PM. Changes in the expression and the functional contribution of Kv1.3 and Kv1.5 channels were studied in contractile and proliferating VSMCs obtained from human donors. Both a Kv1.5 to Kv1.3 switch upon PM and an anti-proliferative effect of Kv1.3 blockers on PDGF-induced proliferation were observed in all vascular beds studied. When investigating the signaling pathways modulated by the blockade of Kv1.3 channels, we found that anti-proliferative effects of Kv1.3 blockers on human coronary artery VSMCs were occluded by selective inhibition of MEK/ERK and PLCγ signaling pathways, but were unaffected upon blockade of PI3K/mTOR pathway. The temporal course of the anti-proliferative effects of Kv1.3 blockers indicates that they have a role in the late signaling events essential for the mitogenic response to growth factors. These findings establish the involvement of Kv1.3 channels in the PM of human VSMCs. Moreover, as current therapies to prevent restenosis rely on mTOR blockers, our results provide the basis for the development of novel, more specific therapies.
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Affiliation(s)
- Pilar Cidad
- Departamento de Bioquímica y Biología Molecular y Fisiología e Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid y CSIC, Edificio IBGM, c/ Sanz y Forés s/n, 47003, Valladolid, Spain
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15
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Gole HKA, Tharp DL, Bowles DK. Upregulation of intermediate-conductance Ca2+-activated K+ channels (KCNN4) in porcine coronary smooth muscle requires NADPH oxidase 5 (NOX5). PLoS One 2014; 9:e105337. [PMID: 25144362 PMCID: PMC4140784 DOI: 10.1371/journal.pone.0105337] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Accepted: 07/23/2014] [Indexed: 02/07/2023] Open
Abstract
Aims NADPH oxidase (NOX) is the primary source of reactive oxygen species (ROS) in vascular smooth muscle cells (SMC) and is proposed to play a key role in redox signaling involved in the pathogenesis of cardiovascular disease. Growth factors and cytokines stimulate coronary SMC (CSMC) phenotypic modulation, proliferation, and migration during atherosclerotic plaque development and restenosis. We previously demonstrated that increased expression and activity of intermediate-conductance Ca2+-activated K+ channels (KCNN4) is necessary for CSMC phenotypic modulation and progression of stenotic lesions. Therefore, the purpose of this study was to determine whether NOX is required for KCNN4 upregulation induced by mitogenic growth factors. Methods and Results Dihydroethidium micro-fluorography in porcine CSMCs demonstrated that basic fibroblast growth factor (bFGF) increased superoxide production, which was blocked by the NOX inhibitor apocynin (Apo). Apo also blocked bFGF-induced increases in KCNN4 mRNA levels in both right coronary artery sections and CSMCs. Similarly, immunohistochemistry and whole cell voltage clamp showed bFGF-induced increases in CSMC KCNN4 protein expression and channel activity were abolished by Apo. Treatment with Apo also inhibited bFGF-induced increases in activator protein-1 promoter activity, as measured by luciferase activity assay. qRT-PCR demonstrated porcine coronary smooth muscle expression of NOX1, NOX2, NOX4, and NOX5 isoforms. Knockdown of NOX5 alone prevented both bFGF-induced upregulation of KCNN4 mRNA and CSMC migration. Conclusions Our findings provide novel evidence that NOX5-derived ROS increase functional expression of KCNN4 through activator protein-1, providing another potential link between NOX, CSMC phenotypic modulation, and atherosclerosis.
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Affiliation(s)
- Hope K. A. Gole
- Department of Biomedical Sciences, University of Missouri Columbia, Columbia, Missouri, United States of America
| | - Darla L. Tharp
- Department of Biomedical Sciences, University of Missouri Columbia, Columbia, Missouri, United States of America
| | - Douglas K. Bowles
- Department of Biomedical Sciences, University of Missouri Columbia, Columbia, Missouri, United States of America
- Dalton Cardiovascular Research Center, University of Missouri Columbia, Columbia, Missouri, United States of America
- Medical Pharmacology and Physiology, University of Missouri Columbia, Columbia, Missouri, United States of America
- * E-mail:
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Ferreira R, Lively S, Schlichter LC. IL-4 type 1 receptor signaling up-regulates KCNN4 expression, and increases the KCa3.1 current and its contribution to migration of alternative-activated microglia. Front Cell Neurosci 2014; 8:183. [PMID: 25071444 PMCID: PMC4077126 DOI: 10.3389/fncel.2014.00183] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 06/14/2014] [Indexed: 01/05/2023] Open
Abstract
The Ca2+-activated K+ channel, KCa3.1 (KCNN4/IK1/SK4), contributes to “classical,” pro-inflammatory activation of microglia, and KCa3.1 blockers have improved the outcome in several rodent models of CNS damage. For instance, blocking KCa3.1 with TRAM-34 rescued retinal ganglion neurons after optic nerve damage in vivo and, reduced p38 MAP kinase activation, production of reactive oxygen and nitrogen species, and neurotoxicity by microglia in vitro. In pursuing the therapeutic potential of KCa3.1 blockers, it is crucial to assess KCa3.1 contributions to other microglial functions and activation states, especially the IL-4-induced “alternative” activation state that can counteract pro-inflammatory states. We recently found that IL-4 increases microglia migration – a crucial function in the healthy and damaged CNS – and that KCa3.1 contributes to P2Y2 receptor-stimulated migration. Here, we discovered that KCa3.1 is greatly increased in alternative-activated rat microglia and then contributes to an enhanced migratory capacity. IL-4 up-regulated KCNN4 mRNA (by 6 h) and greatly increased the KCa3.1 current by 1 day, and this required de novo protein synthesis. The increase in current was sustained for at least 6 days. IL-4 increased microglial migration and this was reversed by blocking KCa3.1 with TRAM-34. A panel of inhibitors of signal-transduction mediators was used to analyze contributions of IL-4-related signaling pathways. Induction of KCNN4 mRNA and KCa3.1 current was mediated specifically through IL-4 binding to the type I receptor and, surprisingly, it required JAK3, Ras/MEK/ERK signaling and the transcription factor, activator protein-1, rather than JAK2, STAT6, or phosphatidylinositol 3-kinase.The same receptor subtype and pathway were required for the enhanced KCa3.1-dependent migration. In providing the first direct signaling link between an IL-4 receptor, expression and roles of an ion channel, this study also highlights the potential importance of KCa3.1 in alternative-activated microglia.
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Affiliation(s)
- Roger Ferreira
- Genes and Development Division, Toronto Western Research Institute, University Health Network Toronto, ON, Canada ; Department of Physiology, University of Toronto Toronto, ON, Canada
| | - Starlee Lively
- Genes and Development Division, Toronto Western Research Institute, University Health Network Toronto, ON, Canada
| | - Lyanne C Schlichter
- Genes and Development Division, Toronto Western Research Institute, University Health Network Toronto, ON, Canada ; Department of Physiology, University of Toronto Toronto, ON, Canada
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17
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Fu RG, Zhang T, Wang L, Du Y, Jia LN, Hou JJ, Yao GL, Liu XD, Zhang L, Chen L, Gui BS, Xue RL. Inhibition of the K+ channel K(Ca)3.1 reduces TGF-β1-induced premature senescence, myofibroblast phenotype transition and proliferation of mesangial cells. PLoS One 2014; 9:e87410. [PMID: 24489911 PMCID: PMC3905019 DOI: 10.1371/journal.pone.0087410] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 12/25/2013] [Indexed: 01/15/2023] Open
Abstract
Objective KCa3.1 channel participates in many important cellular functions. This study planned to investigate the potential involvement of KCa3.1 channel in premature senescence, myofibroblast phenotype transition and proliferation of mesangial cells. Methods & Materials Rat mesangial cells were cultured together with TGF-β1 (2 ng/ml) and TGF-β1 (2 ng/ml) + TRAM-34 (16 nM) separately for specified times from 0 min to 60 min. The cells without treatment served as controls. The location of KCa3.1 channels in mesangial cells was determined with Confocal laser microscope, the cell cycle of mesangial cells was assessed with flow cytometry, the protein and mRNA expression of KCa3.1, α-smooth muscle actin (α-SMA) and fibroblast-specific protein-1 (FSP-1) were detected with Western blot and RT-PCR. One-way analysis of variance (ANOVA) and Student-Newman-Keuls-q test (SNK-q) were used to do statistical analysis. Statistical significance was considered at P<0.05. Results Kca3.1 channels were located in the cell membranes and/or in the cytoplasm of mesangial cells. The percentage of cells in G0-G1 phase and the expression of Kca3.1, α-SMA and FSP-1 were elevated under the induction of TGF-β1 when compared to the control and decreased under the induction of TGF-β1+TRAM-34 when compared to the TGF-β1 induced (P<0.05 or P<0.01). Conclusion Targeted disruption of KCa3.1 inhibits TGF-β1-induced premature aging, myofibroblast-like phenotype transdifferentiation and proliferation of mesangial cells.
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Affiliation(s)
- Rong-Guo Fu
- Department of Nephrology, Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi Province, P.R. China
| | - Tao Zhang
- School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi Province, P.R. China
| | - Li Wang
- Department of Nephrology, Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi Province, P.R. China
| | - Yan Du
- Department of Nephrology, Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi Province, P.R. China
| | - Li-Ning Jia
- Department of Nephrology, Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi Province, P.R. China
| | - Jing-Jing Hou
- School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi Province, P.R. China
| | - Gang-Lian Yao
- Department of Nephrology, Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi Province, P.R. China
| | - Xiao-Dan Liu
- Cadre's ward, Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, P.R. China
| | - Lei Zhang
- Medical Laboratory, Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, P.R. China
| | - Ling Chen
- Department of Oncology, First Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi Province, P.R. China
| | - Bao-Song Gui
- Department of Nephrology, Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi Province, P.R. China
- * E-mail: (RLX); (BSG)
| | - Rong-Liang Xue
- Department of Anesthesia, Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi Province, P.R. China
- * E-mail: (RLX); (BSG)
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18
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Bi D, Toyama K, Lemaître V, Takai J, Fan F, Jenkins DP, Wulff H, Gutterman DD, Park F, Miura H. The intermediate conductance calcium-activated potassium channel KCa3.1 regulates vascular smooth muscle cell proliferation via controlling calcium-dependent signaling. J Biol Chem 2013; 288:15843-53. [PMID: 23609438 PMCID: PMC3668741 DOI: 10.1074/jbc.m112.427187] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 04/12/2013] [Indexed: 01/14/2023] Open
Abstract
The intermediate conductance calcium-activated potassium channel KCa3.1 contributes to a variety of cell activation processes in pathologies such as inflammation, carcinogenesis, and vascular remodeling. We examined the electrophysiological and transcriptional mechanisms by which KCa3.1 regulates vascular smooth muscle cell (VSMC) proliferation. Platelet-derived growth factor-BB (PDGF)-induced proliferation of human coronary artery VSMCs was attenuated by lowering intracellular Ca(2+) concentration ([Ca(2+)]i) and was enhanced by elevating [Ca(2+)]i. KCa3.1 blockade or knockdown inhibited proliferation by suppressing the rise in [Ca(2+)]i and attenuating the expression of phosphorylated cAMP-response element-binding protein (CREB), c-Fos, and neuron-derived orphan receptor-1 (NOR-1). This antiproliferative effect was abolished by elevating [Ca(2+)]i. KCa3.1 overexpression induced VSMC proliferation, and potentiated PDGF-induced proliferation, by inducing CREB phosphorylation, c-Fos, and NOR-1. Pharmacological stimulation of KCa3.1 unexpectedly suppressed proliferation by abolishing the expression and activity of KCa3.1 and PDGF β-receptors and inhibiting the rise in [Ca(2+)]i. The stimulation also attenuated the levels of phosphorylated CREB, c-Fos, and cyclin expression. After KCa3.1 blockade, the characteristic round shape of VSMCs expressing high l-caldesmon and low calponin-1 (dedifferentiation state) was maintained, whereas KCa3.1 stimulation induced a spindle-shaped cellular appearance, with low l-caldesmon and high calponin-1. In conclusion, KCa3.1 plays an important role in VSMC proliferation via controlling Ca(2+)-dependent signaling pathways, and its modulation may therefore constitute a new therapeutic target for cell proliferative diseases such as atherosclerosis.
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Affiliation(s)
- Dan Bi
- From the Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada 89557
| | - Kazuyoshi Toyama
- the Department of Medicine and Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, and
| | - Vincent Lemaître
- From the Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada 89557
| | - Jun Takai
- From the Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada 89557
| | - Fan Fan
- the Department of Medicine and Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, and
| | - David P. Jenkins
- the Department of Pharmacology, University of California, Davis, California 95616
| | - Heike Wulff
- the Department of Pharmacology, University of California, Davis, California 95616
| | - David D. Gutterman
- the Department of Medicine and Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, and
| | - Frank Park
- the Department of Medicine and Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, and
| | - Hiroto Miura
- From the Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada 89557
- the Department of Medicine and Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, and
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Wang LP, Wang Y, Zhao LM, Li GR, Deng XL. Angiotensin II upregulates K(Ca)3.1 channels and stimulates cell proliferation in rat cardiac fibroblasts. Biochem Pharmacol 2013; 85:1486-94. [PMID: 23500546 DOI: 10.1016/j.bcp.2013.02.032] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 02/20/2013] [Accepted: 02/27/2013] [Indexed: 12/01/2022]
Abstract
The proliferation of cardiac fibroblasts is implicated in the pathogenesis of myocardial remodeling and fibrosis. Intermediate-conductance calcium-activated K⁺ channels (K(Ca)3.1 channels) have important roles in cell proliferation. However, it is unknown whether angiotensin II (Ang II), a potent profibrotic molecule, would regulate K(Ca)3.1 channels in cardiac fibroblasts and participate in cell proliferation. In the present study, we investigated whether K(Ca)3.1 channels were regulated by Ang II, and how the channel activity mediated cell proliferation in cultured adult rat cardiac fibroblasts using electrophysiology and biochemical approaches. It was found that mRNA, protein, and current density of K(Ca)3.1 channels were greatly enhanced in cultured cardiac fibroblasts treated with 1 μM Ang II, and the effects were countered by the angiotensin type 1 receptor (AT₁R) blocker losartan, the p38-MAPK inhibitor SB203580, the ERK1/2 inhibitor PD98059, and the PI3K/Akt inhibitor LY294002. Ang II stimulated cell proliferation and the effect was antagonized by the K(Ca)3.1 blocker TRAM-34 and siRNA targeting K(Ca)3.1. In addition, Ang II-induced increase of K(Ca)3.1 expression was attenuated by transfection of activator protein-1 (AP-1) decoy oligodeoxynucleotides. These results demonstrate for the first time that Ang II stimulates cell proliferation mediated by upregulating K(Ca)3.1 channels via interacting with the AT₁R and activating AP-1 complex through ERK1/2, p38-MAPK and PI3K/Akt signaling pathways in cultured adult rat cardiac fibroblasts.
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Affiliation(s)
- Li-Ping Wang
- Department of Physiology and Pathophysiology, School of Medicine, Xi'an Jiaotong University, 76 West Yanta Road, Xi'an, 710061 Shaanxi, China
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20
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Zhao LM, Su XL, Wang Y, Li GR, Deng XL. KCa3.1 channels mediate the increase of cell migration and proliferation by advanced glycation endproducts in cultured rat vascular smooth muscle cells. J Transl Med 2013; 93:159-67. [PMID: 23212096 DOI: 10.1038/labinvest.2012.163] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The mechanisms underlying the involvement of advanced glycation endproducts (AGEs) in diabetic atherosclerosis are not fully understood. The present study was designed to investigate whether intermediate-conductance Ca(2+)-activated K(+) channels (K(Ca)3.1 channels) are involved in migration and proliferation induced by AGEs in cultured rat vascular smooth muscle cells (VSMCs) using approaches of whole-cell patch voltage-clamp, cell proliferation and migration assay, and western blot analysis. It was found that the current density and protein level of K(Ca)3.1 channels were enhanced in cells incubated with AGE-BSA (bovine serum albumin), and the effects were reversed by co-incubation of AGE-BSA with anti-RAGE (anti-receptors of AGEs) antibody. The ERK1/2 inhibitors PD98059 and U0126, the P38-MAPK inhibitors SB203580 and SB202190, or the PI3K inhibitors LY294002 and wortmannin countered the K(Ca)3.1 channel expression by AGE-BSA. In addition, AGE-BAS increased cell migration and proliferation, and the effects were fully reversed with anti-RAGE antibody, the K(Ca)3.1 channel blocker TRAM-34, or K(Ca)3.1 small interfering RNA. These results demonstrate for the first time that AGEs-induced increase of migration and proliferation is related to the upregulation of K(Ca)3.1 channels in rat VMSCs, and the intracellular signals ERK1/2, P38-MAPK and PI3K are involved in the regulation of K(Ca)3.1 channel expression.
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Affiliation(s)
- Li-Mei Zhao
- Department of Physiology and Pathophysiology, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi, China
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Insulin-mediated upregulation of KCa3.1 channels promotes cell migration and proliferation in rat vascular smooth muscle. J Mol Cell Cardiol 2011; 51:51-7. [DOI: 10.1016/j.yjmcc.2011.03.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 03/07/2011] [Accepted: 03/26/2011] [Indexed: 12/29/2022]
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22
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Chang H, Ma YG, Wang YY, Song Z, Li Q, Yang N, Zhao HZ, Feng HZ, Chang YM, Ma J, Yu ZB, Xie MJ. High glucose alters apoptosis and proliferation in HEK293 cells by inhibition of cloned BK Ca channel. J Cell Physiol 2011; 226:1660-75. [PMID: 21413024 DOI: 10.1002/jcp.22497] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
It has been reported that diabetic vascular dysfunction is associated with impaired function of large conductance Ca(2+) -activated K(+) (BK(Ca) ) channels. However, it is unclear whether impaired BK(Ca) channel directly participates in regulating diabetic vascular remodeling by altering cell growth in response to hyperglycemia. In the present study, we investigated the specific role of BK(Ca) channel in controlling apoptosis and proliferation under high glucose concentration (25 mM). The cDNA encoding the α+β1 subunit of BK(Ca) channel, hSloα+β1, was transiently transfected into human embryonic kidney 293 (HEK293) cells. Cloned BK(Ca) currents were recorded by both whole-cell and cell-attached patch clamp techniques. Cell apoptosis was assessed with immunocytochemistry and analysis of fragmented DNA by agarose gel electrophoresis. Cell proliferation was investigated by flow cytometry assays, MTT test, and immunocytochemistry. In addition, the expression of anti-apoptotic protein Bcl-2, intracellular Ca(2+) , and mitochondrial membrane potential (Δψm) were also examined to investigate the possible mechanisms. Our results indicate that inhibition of cloned BK(Ca) channels might be responsible for hyperglycemia-altered apoptosis and proliferation in HEK-hSloα+β1 cells. However, activation of BK(Ca) channel by NS1619 or Tamoxifen significantly induced apoptosis and suppressed proliferation in HEK-hSloα+β1 cells under hyperglycemia condition. When rat cerebral smooth muscle cells were cultured in hyperglycemia, similar findings were observed. Moreover, the possible mechanisms underlying the activation of BK(Ca) channel were associated with decreased expression of Bcl-2, elevation of intracellular Ca(2+) , and a concomitant depolarization of Δψm in HEK-hSloα+β1 cells. In conclusion, cloned BK(Ca) channel directly regulated apoptosis and proliferation of HEK293 cell under hyperglycemia condition.
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Affiliation(s)
- Hui Chang
- Department of Aerospace Physiology, Key Laboratory of Aerospace Medicine of Ministry of Education, Fourth Military Medical University, Xi'an, Shaanxi Province, China
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Cheong A, Li J, Sukumar P, Kumar B, Zeng F, Riches K, Munsch C, Wood IC, Porter KE, Beech DJ. Potent suppression of vascular smooth muscle cell migration and human neointimal hyperplasia by KV1.3 channel blockers. Cardiovasc Res 2010; 89:282-9. [PMID: 20884640 PMCID: PMC3020133 DOI: 10.1093/cvr/cvq305] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIM The aim of the study was to determine the potential for K(V)1 potassium channel blockers as inhibitors of human neoinitimal hyperplasia. METHODS AND RESULTS Blood vessels were obtained from patients or mice and studied in culture. Reverse transcriptase-polymerase chain reaction and immunocytochemistry were used to detect gene expression. Whole-cell patch-clamp, intracellular calcium measurement, cell migration assays, and organ culture were used to assess channel function. K(V)1.3 was unique among the K(V)1 channels in showing preserved and up-regulated expression when the vascular smooth muscle cells switched to the proliferating phenotype. There was strong expression in neointimal formations. Voltage-dependent potassium current in proliferating cells was sensitive to three different blockers of K(V)1.3 channels. Calcium entry was also inhibited. All three blockers reduced vascular smooth muscle cell migration and the effects were non-additive. One of the blockers (margatoxin) was highly potent, suppressing cell migration with an IC(50) of 85 pM. Two of the blockers were tested in organ-cultured human vein samples and both inhibited neointimal hyperplasia. CONCLUSION K(V)1.3 potassium channels are functional in proliferating mouse and human vascular smooth muscle cells and have positive effects on cell migration. Blockers of the channels may be useful as inhibitors of neointimal hyperplasia and other unwanted vascular remodelling events.
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Affiliation(s)
- Alex Cheong
- Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds LS2 9JT, UK
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Calcium-activated potassium channels BK and IK1 are functionally expressed in human gliomas but do not regulate cell proliferation. PLoS One 2010; 5:e12304. [PMID: 20808839 PMCID: PMC2924897 DOI: 10.1371/journal.pone.0012304] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Accepted: 07/25/2010] [Indexed: 01/15/2023] Open
Abstract
Gliomas are morbid brain tumors that are extremely resistant to available chemotherapy and radiology treatments. Some studies have suggested that calcium-activated potassium channels contribute to the high proliferative potential of tumor cells, including gliomas. However, other publications demonstrated no role for these channels or even assigned them antitumorogenic properties. In this work we characterized the expression and functional contribution to proliferation of Ca2+-activated K+ channels in human glioblastoma cells. Quantitative RT-PCR detected transcripts for the big conductance (BK), intermediate conductance (IK1), and small conductance (SK2) K+ channels in two glioblastoma-derived cell lines and a surgical sample of glioblastoma multiforme. Functional expression of BK and IK1 in U251 and U87 glioma cell lines and primary glioma cultures was verified using whole-cell electrophysiological recordings. Inhibitors of BK (paxilline and penitrem A) and IK1 channels (clotrimazole and TRAM-34) reduced U251 and U87 proliferation in an additive fashion, while the selective blocker of SK channels UCL1848 had no effect. However, the antiproliferative properties of BK and IK1 inhibitors were seen at concentrations that were higher than those necessary to inhibit channel activity. To verify specificity of pharmacological agents, we downregulated BK and IK1 channels in U251 cells using gene-specific siRNAs. Although siRNA knockdowns caused strong reductions in the BK and IK1 current densities, neither single nor double gene silencing significantly affected rates of proliferation. Taken together, these results suggest that Ca2+-activated K+ channels do not play a critical role in proliferation of glioma cells and that the effects of pharmacological inhibitors occur through their off-target actions.
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Pritchard TJ, Bowman PS, Jefferson A, Tosun M, Lynch RM, Paul RJ. Na(+)-K(+)-ATPase and Ca(2+) clearance proteins in smooth muscle: a functional unit. Am J Physiol Heart Circ Physiol 2010; 299:H548-56. [PMID: 20543086 DOI: 10.1152/ajpheart.00527.2009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The Na(+)-K(+)-ATPase (NKA) can affect intracellular Ca(2+) concentration regulation via coupling to the Na(+)-Ca(2+) exchanger and may be important in myogenic tone. We previously reported that in mice carrying a transgene for the NKA alpha(2)-isoform in smooth muscle (alpha(2sm+)), the alpha(2)-isoform protein as well as the alpha(1)-isoform (not contained in the transgene) increased to similar degrees (2-7-fold). Aortas from alpha(2sm+) mice relaxed faster from a KCl-induced contraction, hypothesized to be related to more rapid Ca(2+) clearance. To elucidate the mechanisms underlying this faster relaxation, we therefore measured the expression and distribution of proteins involved in Ca(2+) clearance. Na(+)-Ca(2+) exchanger, sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA), and plasma membrane Ca(2+)-ATPase (PMCA) proteins were all elevated up to approximately fivefold, whereas actin, myosin light chain, and calponin proteins were not changed in smooth muscle from alpha(2sm+) mice. Interestingly, the corresponding Ca(2+) clearance mRNA levels were unchanged. Immunocytochemical data indicate that the Ca(2+) clearance proteins are distributed similarly in wild-type and alpha(2sm+) aorta cells. In studies measuring relaxation half-times from a KCl-induced contraction in the presence of pharmacological inhibitors of SERCA and PMCA, we estimated that together these proteins were responsible for approximately 60-70% of relaxation in aorta. Moreover, the percent contribution of SERCA and PMCA to relaxation rates in alpha(2sm+) aorta was not significantly different from that in wild-type aorta. The coordinate expressions of NKA and Ca(2+) clearance proteins without change in the relative contributions of each individual protein to smooth muscle function suggest that NKA may be but one component of a larger functional Ca(2+) clearance system.
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Affiliation(s)
- Tracy J Pritchard
- Molecular and Cellular Physiology, Univ. of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267-0576, USA
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Köhler R, Kaistha BP, Wulff H. Vascular KCa-channels as therapeutic targets in hypertension and restenosis disease. Expert Opin Ther Targets 2010; 14:143-55. [PMID: 20055714 DOI: 10.1517/14728220903540257] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
IMPORTANCE OF THE FIELD Cardiovascular disease is a leading cause of death in modern societies. Hyperpolarizing Ca(2+)-activated K(+) channels (K(Ca)) are important membrane proteins in the control of arterial tone and pathological vascular remodelling and thus could serve as new drug targets. AREAS COVERED IN THIS REVIEW We summarize recent advances in the field of vascular K(Ca) and their roles in cardiovascular pathologies such as hypertension and restenosis disease and draw attention to novel small-molecule channel modulators and their possible therapeutic utility. This review focuses on literature from the last four to five years. WHAT THE READER WILL GAIN Pharmacological opening of endothelial KCa3.1/KCa2.3 channels stimulates endothelium-derived-hyperpolarizing-factor-mediated arteriolar dilation and lowers blood pressure. Inhibition of smooth muscle KCa3.1 channels has beneficial effects in restenosis disease and atherosclerosis. We consider the therapeutic potential of KCa3.1/KCa2.3 openers as novel endothelium-specific antihypertensive drugs as well as of KCa3.1-blockers for the treatment of pathological vascular remodelling and discuss advantages and disadvantages of the pharmacotherapeutic approaches. TAKE HOME MESSAGE Pharmacological manipulation of vascular K(Ca) channels by novel small-molecule modulators offers new venues for alternative treatments of hypertension, restenosis and atherosclerosis. Additional efforts are required to optimize these compounds and to validate them as cardiovascular-protective drugs.
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Affiliation(s)
- Ralf Köhler
- Institute of Medical Biology, Depatrment of Physiology, SDU, J.B. Winsløwsvej 21 3., 5000 Odense C, Denmark.
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Long X, Tharp DL, Georger MA, Slivano OJ, Lee MY, Wamhoff BR, Bowles DK, Miano JM. The smooth muscle cell-restricted KCNMB1 ion channel subunit is a direct transcriptional target of serum response factor and myocardin. J Biol Chem 2009; 284:33671-82. [PMID: 19801679 DOI: 10.1074/jbc.m109.050419] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Large conductance calcium-activated potassium (MaxiK) channels play a pivotal role in maintaining normal arterial tone by regulating the excitation-contraction coupling process. MaxiK channels comprise alpha and beta subunits encoded by Kcnma and the cell-restricted Kcnmb genes, respectively. Although the functionality of MaxiK channel subunits has been well studied, the molecular regulation of their transcription and modulation in smooth muscle cells (SMCs) is incomplete. Using several model systems, we demonstrate down-regulation of Kcnmb1 mRNA upon SMC phenotypic modulation in vitro and in vivo. As part of a broad effort to define all functional CArG elements in the genome (i.e. the CArGome), we discovered two conserved CArG boxes located in the proximal promoter and first intron of the human KCNMB1 gene. Gel shift and chromatin immunoprecipitation assays confirmed serum response factor (SRF) binding to both CArG elements. A luciferase assay showed myocardin (MYOCD)-mediated transactivation of the KCNMB1 promoter in a CArG element-dependent manner. In vivo analysis of the human KCNMB1 promoter disclosed activity in embryonic heart and aortic SMCs; mutation of both conserved CArG elements completely abolished in vivo promoter activity. Forced expression of MYOCD increased Kcnmb1 expression in a variety of rodent and human non-SMC lines with no effect on expression of the Kcnma1 subunit. Conversely, knockdown of Srf resulted in decreases of endogenous Kcnmb1. Functional studies demonstrated MYOCD-induced, iberiotoxin-sensitive potassium currents in porcine coronary SMCs. These results reveal the first ion channel subunit as a direct target of SRF-MYOCD transactivation, providing further insight into the role of MYOCD as a master regulator of the SMC contractile phenotype.
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Affiliation(s)
- Xiaochun Long
- Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
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Pantaleo A, De Franceschi L, Ferru E, Vono R, Turrini F. Current knowledge about the functional roles of phosphorylative changes of membrane proteins in normal and diseased red cells. J Proteomics 2009; 73:445-55. [PMID: 19758581 DOI: 10.1016/j.jprot.2009.08.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Revised: 07/17/2009] [Accepted: 08/27/2009] [Indexed: 12/20/2022]
Abstract
With the advent of proteomic techniques the number of known post-translational modifications (PTMs) affecting red cell membrane proteins is rapidly growing but the understanding of their role under physiological and pathological conditions is incompletely established. The wide range of hereditary diseases affecting different red cell membrane functions and the membrane modifications induced by malaria parasite intracellular growth represent a unique opportunity to study PTMs in response to variable cellular stresses. In the present review, some of the major areas of interest in red cell membrane research have been considered as modifications of erythrocyte deformability and maintenance of the surface area, membrane transport alterations, and removal of diseased and senescent red cells. In all mentioned research areas the functional roles of PTMs are prevalently restricted to the phosphorylative changes of the more abundant membrane proteins. The insufficient information about the PTMs occurring in a large majority of the red membrane proteins and the general lack of mass spectrometry data evidence the need of new comprehensive, proteomic approaches to improve the understanding of the red cell membrane physiology.
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Affiliation(s)
- Antonella Pantaleo
- Department of Genetics, Biology and Biochemistry, University of Turin, via Santena 5 bis, 10126 Turin, Italy.
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Renal fibrosis is attenuated by targeted disruption of KCa3.1 potassium channels. Proc Natl Acad Sci U S A 2009; 106:14518-23. [PMID: 19706538 DOI: 10.1073/pnas.0903458106] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Proliferation of interstitial fibroblasts is a hallmark of progressive renal fibrosis commonly resulting in chronic kidney failure. The intermediate-conductance Ca(2+)-activated K(+) channel (K(Ca)3.1) has been proposed to promote mitogenesis in several cell types and contribute to disease states characterized by excessive proliferation. Here, we hypothesized that K(Ca)3.1 activity is pivotal for renal fibroblast proliferation and that deficiency or pharmacological blockade of K(Ca)3.1 suppresses development of renal fibrosis. We found that mitogenic stimulation up-regulated K(Ca)3.1 in murine renal fibroblasts via a MEK-dependent mechanism and that selective blockade of K(Ca)3.1 functions potently inhibited fibroblast proliferation by G(0)/G(1) arrest. Renal fibrosis induced by unilateral ureteral obstruction (UUO) in mice was paralleled by a robust up-regulation of K(Ca)3.1 in affected kidneys. Mice lacking K(Ca)3.1 (K(Ca)3.1(-/-)) showed a significant reduction in fibrotic marker expression, chronic tubulointerstitial damage, collagen deposition and alphaSMA(+) cells in kidneys after UUO, whereas functional renal parenchyma was better preserved. Pharmacological treatment with the selective K(Ca)3.1 blocker TRAM-34 similarly attenuated progression of UUO-induced renal fibrosis in wild-type mice and rats. In conclusion, our data demonstrate that K(Ca)3.1 is involved in renal fibroblast proliferation and fibrogenesis and suggest that K(Ca)3.1 may represent a therapeutic target for the treatment of fibrotic kidney disease.
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Yang XP, Pei ZH, Ren J. MAKING UP OR BREAKING UP: THE TORTUOUS ROLE OF PLATELET-DERIVED GROWTH FACTOR IN VASCULAR AGEING. Clin Exp Pharmacol Physiol 2009; 36:739-47. [DOI: 10.1111/j.1440-1681.2009.05182.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Thompson J, Begenisich T. Mechanistic details of BK channel inhibition by the intermediate conductance, Ca2+-activated K channel. Channels (Austin) 2009; 3:194-204. [PMID: 19574736 DOI: 10.4161/chan.3.3.9043] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Salivary gland acinar cells have two types of Ca(2+)-activated K channels required for fluid secretion: the intermediate conductance (IK1) channel and the large conductance (BK) channel. Activation of IK1 inhibits BK channels including in small, cell-free, excised membrane patches. As a first step toward understanding the mechanism underlying this interaction, we examined its voltage sensitivity. We found that the IK1-induced inhibition of BK channels was only weakly voltage dependent and not accompanied by alteration in BK gating kinetics. These actions of IK1 on BK channels are not consistent with a mechanism whereby activation of IK1 causes a shift of the BK channel's voltage dependence as occurs for many BK modulatory processes. In a search for other clues about the interaction mechanism, we noted that the N-terminus of the IK1 channel shares some chemical features with the N-terminal regions of two BK subunits known to inhibit BK activity by blocking the cytoplasmic end of the BK pore. Thus, we tested the idea that the N-terminus of IK1 channels may act similarly. We found that a peptide derived from the N-terminal region of the IK1 protein blocked BK channels. Significantly, we also found that the activation of IK1 channels competed with block by the N-terminus peptide. Thus, the activation of IK1 channels inhibits BK channels by a mechanism that involves block of the cytoplasmic pore, not an alteration in the voltage dependence of BK gating. The mediator of this cytoplasmic pore block may be the IK1 N-terminus.
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Affiliation(s)
- Jill Thompson
- Department of Pharmacology and Physiology and the Center for Oral Biology, University of Rochester Medical Center, Rochester, NY 14642, USA
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De Marchi U, Sassi N, Fioretti B, Catacuzzeno L, Cereghetti GM, Szabò I, Zoratti M. Intermediate conductance Ca2+-activated potassium channel (KCa3.1) in the inner mitochondrial membrane of human colon cancer cells. Cell Calcium 2009; 45:509-16. [PMID: 19406468 DOI: 10.1016/j.ceca.2009.03.014] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 03/13/2009] [Accepted: 03/23/2009] [Indexed: 11/28/2022]
Abstract
Patch-clamping mitoplasts isolated from human colon carcinoma 116 cells has allowed the identification and characterization of the intermediate conductance Ca(2+)-activated K(+)-selective channel K(Ca)3.1, previously studied only in the plasma membrane of various cell types. Its identity has been established by its biophysical and pharmacological properties. Its localisation in the inner membrane of mitochondria is indicated by Western blots of subcellular fractions, by recording of its activity in mitochondria made fluorescent by a mitochondria-targeted fluorescent protein and by the co-presence of channels considered to be markers of the inner membrane. Moderate increases of mitochondrial matrix [Ca(2+)] will cause mtK(Ca)3.1 opening, thus linking inner membrane K(+) permeability and transmembrane potential to Ca(2+) signalling.
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Affiliation(s)
- Umberto De Marchi
- Department of Biomedical Sciences, University of Padova, Padova, Italy
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Grgic I, Kaistha BP, Hoyer J, Köhler R. Endothelial Ca+-activated K+ channels in normal and impaired EDHF-dilator responses--relevance to cardiovascular pathologies and drug discovery. Br J Pharmacol 2009; 157:509-26. [PMID: 19302590 DOI: 10.1111/j.1476-5381.2009.00132.x] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The arterial endothelium critically contributes to blood pressure control by releasing vasodilating autacoids such as nitric oxide, prostacyclin and a third factor or pathway termed 'endothelium-derived hyperpolarizing factor' (EDHF). The nature of EDHF and EDHF-signalling pathways is not fully understood yet. However, endothelial hyperpolarization mediated by the Ca(2+)-activated K(+) channels (K(Ca)) has been suggested to play a critical role in initializing EDHF-dilator responses in conduit and resistance-sized arteries of many species including humans. Endothelial K(Ca) currents are mediated by the two K(Ca) subtypes, intermediate-conductance K(Ca) (KCa3.1) (also known as, a.k.a. IK(Ca)) and small-conductance K(Ca) type 3 (KCa2.3) (a.k.a. SK(Ca)). In this review, we summarize current knowledge about endothelial KCa3.1 and KCa2.3 channels, their molecular and pharmacological properties and their specific roles in endothelial function and, particularly, in the EDHF-dilator response. In addition we focus on recent experimental evidences derived from KCa3.1- and/or KCa2.3-deficient mice that exhibit severe defects in EDHF signalling and elevated blood pressures, thus highlighting the importance of the KCa3.1/KCa2.3-EDHF-dilator system for blood pressure control. Moreover, we outline differential and overlapping roles of KCa3.1 and KCa2.3 for EDHF signalling as well as for nitric oxide synthesis and discuss recent evidence for a heterogeneous (sub) cellular distribution of KCa3.1 (at endothelial projections towards the smooth muscle) and KCa2.3 (at inter-endothelial borders and caveolae), which may explain their distinct roles for endothelial function. Finally, we summarize the interrelations of altered KCa3.1/KCa2.3 and EDHF system impairments with cardiovascular disease states such as hypertension, diabetes, dyslipidemia and atherosclerosis and discuss the therapeutic potential of KCa3.1/KCa2.3 openers as novel types of blood pressure-lowering drugs.
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Affiliation(s)
- Ivica Grgic
- Department of Internal Medicine-Nephrology, Philipps-University, Marburg, Germany
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Intermediate-conductance Ca2+-activated K+ channels (IKCa1) regulate human prostate cancer cell proliferation through a close control of calcium entry. Oncogene 2009; 28:1792-806. [DOI: 10.1038/onc.2009.25] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Romanenko VG, Roser KS, Melvin JE, Begenisich T. The role of cell cholesterol and the cytoskeleton in the interaction between IK1 and maxi-K channels. Am J Physiol Cell Physiol 2009; 296:C878-88. [PMID: 19176762 DOI: 10.1152/ajpcell.00438.2008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Recently, we demonstrated a novel interaction between large-conductance (maxi-K or K(Ca)1.1) and intermediate-conductance (IK1 or K(Ca)3.1) Ca(2+)-activated K channels: activation of IK1 channels causes the inhibition of maxi-K activity (Thompson J and Begenisich T. J Gen Physiol 127: 159-169, 2006). Here we show that the interaction between these two channels can be regulated by the membrane cholesterol level in parotid acinar cells. Depletion of cholesterol using methyl-beta-cyclodextrin weakened, while cholesterol enrichment increased, the ability of IK1 activation to inhibit maxi-K channels. Cholesterol's stereoisomer, epicholesterol, was unable to substitute for cholesterol in the interaction between the two K channels, suggesting a specific cholesterol-protein interaction. This suggestion was strengthened by the results of experiments in which cholesterol was replaced by coprostanol and epicoprostanol. These two sterols have nearly identical effects on membrane physical properties and cholesterol-rich microdomain stability, but had very different effects on the IK1/maxi-K interaction. In addition, the IK1/maxi-K interaction was unaltered in cells lacking caveolin, the protein essential for formation and stability of caveolae. Finally, disruption of the actin cytoskeleton restored the IK1-induced maxi-K inhibition that was lost with cell cholesterol depletion, demonstrating the importance of an intact cytoskeleton for the cholesterol-dependent regulation of the IK1/maxi-K interaction.
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Affiliation(s)
- Victor G Romanenko
- Dept. of Pharmacology, Box 711, Univ. of Rochester Medical Center, Rochester, NY 14642, USA
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De Franceschi L, Biondani A, Carta F, Turrini F, Laudanna C, Deana R, Brunati AM, Turretta L, Iolascon A, Perrotta S, Elson A, Bulato C, Brugnara C. PTPepsilon has a critical role in signaling transduction pathways and phosphoprotein network topology in red cells. Proteomics 2008; 8:4695-708. [PMID: 18924107 PMCID: PMC3008556 DOI: 10.1002/pmic.200700596] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Indexed: 12/31/2022]
Abstract
Protein tyrosine phosphatases (PTPs) are crucial components of cellular signal transduction pathways. Here, we report that red blood cells (RBCs) from mice lacking PTPepsilon (Ptpre(-/-)) exhibit (i) abnormal morphology; (ii) increased Ca(2+)-activated-K(+) channel activity, which was partially blocked by the Src family kinases (SFKs) inhibitor PP1; and (iii) market perturbation of the RBC membrane tyrosine (Tyr-) phosphoproteome, indicating an alteration of RBC signal transduction pathways. Using the signaling network computational analysis of the Tyr-phosphoproteomic data, we identified seven topological clusters. We studied cluster 1 containing Fyn, SFK, and Syk another tyrosine kinase. In Ptpre(-/-)mouse RBCs, the activity of Fyn was increased while Syk kinase activity was decreased compared to wild-type RBCs, validating the network computational analysis, and indicating a novel signaling pathway, which involves Fyn and Syk in regulation of red cell morphology.
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Affiliation(s)
- Lucia De Franceschi
- Department of Clinical and Experimental Medicine, Section of Internal Medicine, University of Verona, Verona, Italy.
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Lounsbury KM. Preventing stenosis by local inhibition of KCa3.1: a finger on the phenotypic switch. Arterioscler Thromb Vasc Biol 2008; 28:1036-8. [PMID: 18495973 DOI: 10.1161/atvbaha.108.164988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Ion channel switching and activation in smooth-muscle cells of occlusive vascular diseases. Biochem Soc Trans 2008; 35:890-4. [PMID: 17956239 DOI: 10.1042/bst0350890] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Blood vessels are essential for animal life, allowing flow of oxygen and nutrients to tissues and removal of waste products. Consequently, inappropriate remodelling of blood vessels, resulting in occlusion, can lead to disabling or catastrophic events: heart attacks, strokes and claudication. An important cell type of remodelling is the VSMC (vascular smooth-muscle cell), a fascinating cell that contributes significantly to occlusive vascular diseases by virtue of its ability to 'modulate' to a cell that no longer contracts and arranges radially in the medial layer of the vessel wall but migrates, invades, proliferates and adopts phenotypes of other cells. An intriguing aspect of modulation is switching to different ion transport systems. Initial events include loss of the Ca(V)1.2 (L-type voltage-gated calcium) channel and gain of the K(Ca)3.1 (IKCa) potassium channel, which putatively occur to enable membrane hyperpolarization that increases rather than decreases a type of calcium entry coupled with cell cycle activity, cell proliferation and cell migration. This type of calcium entry is related to store- and receptor-operated calcium entry phenomena, which, in VSMCs, are contributed to by TRPC [TRP (transient receptor potential) canonical] channel subunits. Instead of being voltage-gated, these channels are chemically gated - importantly, by key phospholipid factors of vascular development and disease. This brief review focuses on the hypothesis that the transition to a modulated cell may require a switch from predominantly voltage- to predominantly lipid-sensing ion channels.
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Brueggemann LI, Moran CJ, Barakat JA, Yeh JZ, Cribbs LL, Byron KL. Vasopressin stimulates action potential firing by protein kinase C-dependent inhibition of KCNQ5 in A7r5 rat aortic smooth muscle cells. Am J Physiol Heart Circ Physiol 2006; 292:H1352-63. [PMID: 17071736 PMCID: PMC2577603 DOI: 10.1152/ajpheart.00065.2006] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
[Arg(8)]-vasopressin (AVP), at low concentrations (10-500 pM), stimulates oscillations in intracellular Ca(2+) concentration (Ca(2+) spikes) in A7r5 rat aortic smooth muscle cells. Our previous studies provided biochemical evidence that protein kinase C (PKC) activation and phosphorylation of voltage-sensitive K(+) (K(v)) channels are crucial steps in this process. In the present study, K(v) currents (I(Kv)) and membrane potential were measured using patch clamp techniques. Treatment of A7r5 cells with 100 pM AVP resulted in significant inhibition of I(Kv). This effect was associated with gradual membrane depolarization, increased membrane resistance, and action potential (AP) generation in the same cells. The AVP-sensitive I(Kv) was resistant to 4-aminopyridine, iberiotoxin, and glibenclamide but was fully inhibited by the selective KCNQ channel blockers linopirdine (10 microM) and XE-991 (10 microM) and enhanced by the KCNQ channel activator flupirtine (10 microM). BaCl(2) (100 microM) or linopirdine (5 microM) mimicked the effects of AVP on K(+) currents, AP generation, and Ca(2+) spiking. Expression of KCNQ5 was detected by RT-PCR in A7r5 cells and freshly isolated rat aortic smooth muscle. RNA interference directed toward KCNQ5 reduced KCNQ5 protein expression and resulted in a significant decrease in I(Kv) in A7r5 cells. I(Kv) was also inhibited in response to the PKC activator 4beta-phorbol 12-myristate 13-acetate (10 nM), and the inhibition of I(Kv) by AVP was prevented by the PKC inhibitor calphostin C (250 nM). These results suggest that the stimulation of Ca(2+) spiking by physiological concentrations of AVP involves PKC-dependent inhibition of KCNQ5 channels and increased AP firing in A7r5 cells.
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