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Seo CH, Cui HS, Kim JB. Altered K Ca3.1 expression following burn injury and the therapeutic potential of TRAM-34 in post-burn hypertrophic scar formation. Transl Res 2021; 236:133-146. [PMID: 33905948 DOI: 10.1016/j.trsl.2021.04.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 04/09/2021] [Accepted: 04/18/2021] [Indexed: 01/16/2023]
Abstract
Hypertrophic scars are the most common post-burn complications characterized by fibroblast proliferation and excessive extracellular matrix deposition. The intermediate-conductance Ca2+-activated K+ channel (KCa3.1) mediates fibroblast activation, resulting in several fibrotic diseases; however, this channel's role in the formation of post-burn hypertrophic skin scars remains unknown. Herein, we investigated the role of KCa3.1 and the therapeutic potential of TRAM-34, a selective inhibitor of KCa3.1, in hypertrophic skin scar formation following burn injury. Cytosolic Ca2+ levels, the expression of KCa3.1 and hypertrophic markers, and the proliferation of skin fibroblasts obtained directly from patients with third-degree burns who consequently developed post-burn hypertrophic scars were assessed. The anti-fibrotic effect of KCa3.1 inhibition by TRAM-34 was evaluated in vitro (fibroblasts) and in vivo (mouse burn models). Fibroblasts from burn wounds exhibited remarkably higher levels of cytosolic Ca2+ than normal cells. KCa3.1 expression was markedly higher in the membrane fraction but lower in the cytosolic fraction of burn wound fibroblasts than in normal cells. Selective inhibition of KCa3.1 by TRAM-34 markedly reduced not only the proliferation of burn wound fibroblasts but also the expression of hypertrophic markers in these cells. Anti-scarring molecular, histological, and visual effects of TRAM-34 were confirmed in murine burn models. Altered subcellular expression of KCa3.1 is a novel mechanism underlying the cellular response to burn injury. Our results suggest that selective inhibition of KCa3.1 by TRAM-34 has therapeutic potential against post-burn hypertrophic scar formation.
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Affiliation(s)
- Cheong Hoon Seo
- Department of Rehabilitation Medicine, Hangang Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea
| | - Hui Song Cui
- Burn Institute, Hangang Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea
| | - June-Bum Kim
- Department of Pediatrics, Hangang Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea.
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Increased Levels of ER Stress and Apoptosis in a Sheep Model for Pulmonary Fibrosis Are Alleviated by In Vivo Blockade of the KCa3.1 Ion Channel. Can Respir J 2021; 2021:6683195. [PMID: 33828632 PMCID: PMC8004363 DOI: 10.1155/2021/6683195] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 03/04/2021] [Accepted: 03/10/2021] [Indexed: 12/26/2022] Open
Abstract
Idiopathic pulmonary fibrosis (IPF) is a fatal interstitial lung disease, characterized by progressive damage to the lung tissues. Apoptosis and endoplasmic reticulum stress (ER stress) in type II alveolar epithelial cells (AECs) and lung macrophages have been linked with the development of IPF. Therefore, apoptosis- and ER stress-targeted therapies have drawn attention as potential avenues for treatment of IPF. The calcium-activated potassium ion channel KCa3.1 has been proposed as a potential therapeutic target for fibrotic diseases including IPF. While KCa3.1 is expressed in AECs and macrophages, its influence on ER stress and apoptosis during the disease process is unclear. We utilized a novel sheep model of pulmonary fibrosis to demonstrate that apoptosis and ER stress occur in type II AECs and macrophages in sheep with bleomycin-induced lung fibrosis. Apoptosis in type II AEC and macrophages was identified using the TUNEL method of tagging fragmented nuclear DNA, while ER stress was characterized by increased expression of GRP-78 ER chaperone proteins. We demonstrated that apoptosis and ER stress in type II AECs and macrophages increased significantly 2 weeks after the final bleomycin infusion and remained high for up to 7 weeks post-bleomycin injury. Senicapoc treatment significantly reduced the rates of ER stress in type II AECs and macrophages that were resident in bleomycin-infused lung segments. There were also significant reductions in the rates of apoptosis of type II AECs and macrophages in the lung segments of senicapoc-treated sheep. In vivo blockade of the KCa3.1 ion channel alleviates the ER stress and apoptosis in type II AECs and macrophages, and this effect potentially contributes to the anti-fibrotic effects of senicapoc.
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SK4 oncochannels regulate calcium entry and promote cell migration in KRAS-mutated colorectal cancer. Cell Calcium 2021; 96:102384. [PMID: 33676318 DOI: 10.1016/j.ceca.2021.102384] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 02/07/2021] [Accepted: 02/22/2021] [Indexed: 11/21/2022]
Abstract
BACKGROUND Colorectal cancer (CRC) metastases are the main cause of CRC mortality. Intracellular Ca2+ regulates cell migration and invasion, key factors for metastases. Ca2+ also activates Ca2+-dependent potassium channels which in turn affect Ca2+ driving force. We have previously reported that the expression of the Ca2+ activated potassium channel KCNN4 (SK4) is higher in CRC primary tumors compared to normal tissues. Here, we aimed to investigate the role of SK4 in the physiology of CRC. RESULTS SK4 protein expression is enhanced in CRC tissues compared to normal colon tissues, with a higher level of KCNN4 in CRC patients with KRAS mutations. At the cellular level, we found that SK4 regulates the membrane potential of HCT116 cells. We also found that its inhibition reduced store operated Ca2+ entry (SOCE) and constitutive Ca2+ entry (CCE), while reducing cell migration. We also found that the activity of SK4 is linked to resistance pathways such as KRAS mutation and the expression of NRF2 and HIF-1α. In addition, the pharmacological inhibition of SK4 reduced intracellular reactive oxygen species (ROS) production, NRF2 expression and HIF1α stabilization. CONCLUSION Our results suggest that SK4 contributes to colorectal cancer cell migration and invasion by modulating both Ca2+ entry and ROS regulation. Therefore, SK4 could be a potential target to reduce metastasis in KRAS-mutated CRC.
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Weisbrod D. Small and Intermediate Calcium Activated Potassium Channels in the Heart: Role and Strategies in the Treatment of Cardiovascular Diseases. Front Physiol 2020; 11:590534. [PMID: 33329039 PMCID: PMC7719780 DOI: 10.3389/fphys.2020.590534] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 10/02/2020] [Indexed: 12/11/2022] Open
Abstract
Calcium-activated potassium channels are a heterogeneous family of channels that, despite their different biophysical characteristics, structures, and pharmacological signatures, play a role of transducer between the ubiquitous intracellular calcium signaling and the electric variations of the membrane. Although this family of channels was extensively described in various excitable and non-excitable tissues, an increasing amount of evidences shows their functional role in the heart. This review aims to focus on the physiological role and the contribution of the small and intermediate calcium-activated potassium channels in cardiac pathologies.
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Catacuzzeno L, Sforna L, Esposito V, Limatola C, Franciolini F. Ion Channels in Glioma Malignancy. Rev Physiol Biochem Pharmacol 2020; 181:223-267. [DOI: 10.1007/112_2020_44] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Upregulation of Potassium Voltage-Gated Channel Subfamily J Member 2 Levels in the Lungs of Patients with Idiopathic Pulmonary Fibrosis. Can Respir J 2020; 2020:3406530. [PMID: 32184906 PMCID: PMC7061125 DOI: 10.1155/2020/3406530] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 01/23/2020] [Indexed: 01/23/2023] Open
Abstract
Background Fibroblast dysfunction is the main pathogenic mechanism underpinning idiopathic pulmonary fibrosis (IPF). Potassium voltage-gated channel subfamily J member 2 (KCNJ2) plays critical roles in the proliferation of myofibroblasts and in the development of cardiac fibrosis. Objectives This study aimed to evaluate the role of KCNJ2 in IPF. Methods KCNJ2 mRNA expression was measured using real-time PCR in fibroblasts from IPF patients and normal controls (NCs). Protein concentrations were measured by ELISA in bronchoalveolar lavage (BAL) fluid obtained from NCs (n = 30), IPF (n = 30), IPF (n = 30), IPF (n = 30), IPF (n = 30), IPF ( Results KCNJ2 mRNA expression was measured using real-time PCR in fibroblasts from IPF patients and normal controls (NCs). Protein concentrations were measured by ELISA in bronchoalveolar lavage (BAL) fluid obtained from NCs (n = 30), IPF (n = 30), IPF (p < 0.001). KCNJ2 protein levels in BAL fluid were significantly higher in IPF (6.587 [1.441–26.01] ng/mL) than in NCs (0.084 [0.00–0.260] ng/mL, p < 0.001). KCNJ2 protein levels in BAL fluid were significantly higher in IPF (6.587 [1.441–26.01] ng/mL) than in NCs (0.084 [0.00–0.260] ng/mL, p < 0.001). KCNJ2 protein levels in BAL fluid were significantly higher in IPF (6.587 [1.441–26.01] ng/mL) than in NCs (0.084 [0.00–0.260] ng/mL, p < 0.001). KCNJ2 protein levels in BAL fluid were significantly higher in IPF (6.587 [1.441–26.01] ng/mL) than in NCs (0.084 [0.00–0.260] ng/mL, p < 0.001). KCNJ2 protein levels in BAL fluid were significantly higher in IPF (6.587 [1.441–26.01] ng/mL) than in NCs (0.084 [0.00–0.260] ng/mL, Conclusion KCNJ2 may participate in the development of IPF, and its protein level may be a candidate diagnostic and therapeutic molecule for IPF.
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Mann C, Kaistha B, Kacik M, Stiewe T, Hoyer J. Downregulation of miR-503 in Activated Kidney Fibroblasts Disinhibits KCNN4 in an in Vitro Model of Kidney Fibrosis. Kidney Blood Press Res 2019; 44:113-122. [DOI: 10.1159/000498875] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/05/2019] [Indexed: 11/19/2022] Open
Abstract
Background/Aims: Activated fibroblasts are key controllers of extracellular matrix turnover in kidney fibrosis, the pathophysiological end stage of chronic kidney disease. The proliferation of activated fibroblasts depends on the expression of the calcium-dependent potassium channel KCNN4. Expression of this ion channel is upregulated in fibrotic kidneys. Genetic and pharmacological blockade of KCNN4 inhibits fibrosis in vitro and in vivo. Methods: We studied the regulation of KCNN4 and possible involvement of miRNAs in an in-vitro fibrosis model using murine kidney fibroblasts. We tested fibroblast proliferation, channel function, channel expression and expression regulation after FGF-2 stimulation. Results: Proliferation was significantly increased by FGF-2, channel current and expression were almost doubled (+ 91% and +125%, respectively). MiRNA microarray identified upregulation of miRNA-503, which targets RAF1 and thereby controls KCNN4-expression via disinhibition of the Ras/Raf/MEK/ ERK-cascade. Conclusion: This data show a) a profound upregulation of KCNN4 in stimulated fibroblast and b) identifies miR-503 as a regulator of KCNN4 expression.
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Cancer-Associated Intermediate Conductance Ca 2+-Activated K⁺ Channel K Ca3.1. Cancers (Basel) 2019; 11:cancers11010109. [PMID: 30658505 PMCID: PMC6357066 DOI: 10.3390/cancers11010109] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 01/10/2019] [Accepted: 01/13/2019] [Indexed: 12/14/2022] Open
Abstract
Several tumor entities have been reported to overexpress KCa3.1 potassium channels due to epigenetic, transcriptional, or post-translational modifications. By modulating membrane potential, cell volume, or Ca2+ signaling, KCa3.1 has been proposed to exert pivotal oncogenic functions in tumorigenesis, malignant progression, metastasis, and therapy resistance. Moreover, KCa3.1 is expressed by tumor-promoting stroma cells such as fibroblasts and the tumor vasculature suggesting a role of KCa3.1 in the adaptation of the tumor microenvironment. Combined, this features KCa3.1 as a candidate target for innovative anti-cancer therapy. However, immune cells also express KCa3.1 thereby contributing to T cell activation. Thus, any strategy targeting KCa3.1 in anti-cancer therapy may also modulate anti-tumor immune activity and/or immunosuppression. The present review article highlights the potential of KCa3.1 as an anti-tumor target providing an overview of the current knowledge on its function in tumor pathogenesis with emphasis on vasculo- and angiogenesis as well as anti-cancer immune responses.
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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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Chen Y, Kuang D, Zhao X, Chen D, Wang X, Yang Q, Wan J, Zhu Y, Wang Y, Zhang S, Wang Y, Tang Q, Masuzawa M, Wang G, Duan Y. miR-497-5p inhibits cell proliferation and invasion by targeting KCa3.1 in angiosarcoma. Oncotarget 2018; 7:58148-58161. [PMID: 27531900 PMCID: PMC5295420 DOI: 10.18632/oncotarget.11252] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 07/26/2016] [Indexed: 11/25/2022] Open
Abstract
Angiosarcoma is a rare malignant mesenchymal tumor with poor prognosis. We aimed to identify malignancy-associated miRNAs and their target genes, and explore biological functions of miRNA and its target in angiosarcoma. By miRNA microarrays and reverse transcription polymerase chain reaction, we identified 1 up-regulated miRNA (miR-222-3p) and 3 down-regulated miRNAs (miR-497-5p, miR-378-3p and miR-483-5p) in human angiosarcomas compared with human capillary hemangiomas. The intermediate-conductance calcium activated potassium channel KCa3.1 was one of the putative target genes of miR-497-5p, and marked up-regulation of KCa3.1 was detected in angiosarcoma biopsy specimens by immunohistochemistry. The inverse correlation of miR-497-5p and KCa3.1 also was observed in the ISO-HAS angiosarcoma cell line at the mRNA and protein levels. The direct targeting of KCa3.1 by miR-497-5p was evidenced by reduced luciferase activity due to complementary binding of miR-497-5p to KCa3.1 mRNA 3′ untranslated region. For the functional role of miR-497-5p/KCa3.1 pair, we showed that application of TRAM-34, a specific KCa3.1 channel blocker, or transfection of ISO-HAS cells with KCa3.1 siRNA or miR-497-5p mimics inhibited cell proliferation, cell cycle progression, and invasion by down-regulating cell-cycle related proteins including cyclin D1, surviving and P53 and down-regulating matrix metallopeptidase 9. In an in vivo angiosarcoma xenograft model, TRAM-34 or miR-497-5p mimics both inhibited tumor growth. In conclusion, the tumor suppressor miR-497-5p down-regulates KCa3.1 expression and contributes to the inhibition of angiosarcoma malignancy development. The miR-497-5p or KCa3.1 might be potential new targets for angiosarcoma treatment.
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Affiliation(s)
- Yaobing Chen
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Dong Kuang
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xia Zhao
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Department of Pathology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Dong Chen
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xiaoyan Wang
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Qin Yang
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jie Wan
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yuanli Zhu
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yu Wang
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Shiying Zhang
- Department of Pathology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Ying Wang
- Department of Pathology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Qiang Tang
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Mikio Masuzawa
- Department of Regulation Biochemistry, Kitasato University School of Allied Health Sciences, Minamiku, Sagamihara Kanagawa, 252-0329, Japan
| | - Guoping Wang
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Department of Pathology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yaqi Duan
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Department of Pathology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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Tsui JH, Janebodin K, Ieronimakis N, Yama DMP, Yang HS, Chavanachat R, Hays AL, Lee H, Reyes M, Kim DH. Harnessing Sphingosine-1-Phosphate Signaling and Nanotopographical Cues To Regulate Skeletal Muscle Maturation and Vascularization. ACS NANO 2017; 11:11954-11968. [PMID: 29156133 PMCID: PMC6133580 DOI: 10.1021/acsnano.7b00186] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Despite possessing substantial regenerative capacity, skeletal muscle can suffer from loss of function due to catastrophic traumatic injury or degenerative disease. In such cases, engineered tissue grafts hold the potential to restore function and improve patient quality of life. Requirements for successful integration of engineered tissue grafts with the host musculature include cell alignment that mimics host tissue architecture and directional functionality, as well as vascularization to ensure tissue survival. Here, we have developed biomimetic nanopatterned poly(lactic-co-glycolic acid) substrates conjugated with sphingosine-1-phosphate (S1P), a potent angiogenic and myogenic factor, to enhance myoblast and endothelial maturation. Primary muscle cells cultured on these functionalized S1P nanopatterned substrates developed a highly aligned and elongated morphology and exhibited higher expression levels of myosin heavy chain, in addition to genes characteristic of mature skeletal muscle. We also found that S1P enhanced angiogenic potential in these cultures, as evidenced by elevated expression of endothelial-related genes. Computational analyses of live-cell videos showed a significantly improved functionality of tissues cultured on S1P-functionalized nanopatterns as indicated by greater myotube contraction displacements and velocities. In summary, our study demonstrates that biomimetic nanotopography and S1P can be combined to synergistically regulate the maturation and vascularization of engineered skeletal muscles.
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Affiliation(s)
- Jonathan H. Tsui
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Kajohnkiart Janebodin
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
- Department of Pathology, University of Washington, Seattle, Washington, USA
- Department of Anatomy, Faculty of Dentistry, Mahidol University, Bangkok, Thailand
| | - Nicholas Ieronimakis
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
- Department of Pathology, University of Washington, Seattle, Washington, USA
- Department of Clinical Investigation, Madigan Army Medical Center, Tacoma, Washington, USA
| | - David M. P. Yama
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Hee Seok Yang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
- Department of Nanobiomedical Science and BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, South Korea
| | | | - Aislinn L. Hays
- Department of Pathology, University of Washington, Seattle, Washington, USA
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Haeshin Lee
- Department of Chemistry and the Graduate School of Nanoscience and Technology, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Morayma Reyes
- Department of Pathology, University of Washington, Seattle, Washington, USA
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Deok-Ho Kim
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington, USA
- Center for Cardiovascular Biology, University of Washington, Seattle, Washington, USA
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KCa3.1 mediates dysfunction of tubular autophagy in diabetic kidneys via PI3k/Akt/mTOR signaling pathways. Sci Rep 2016; 6:23884. [PMID: 27029904 PMCID: PMC4814925 DOI: 10.1038/srep23884] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 02/16/2016] [Indexed: 02/06/2023] Open
Abstract
Autophagy is emerging as an important pathway in many diseases including diabetic nephropathy. It is acknowledged that oxidative stress plays a critical role in autophagy dysfunction and diabetic nephropathy, and KCa3.1 blockade ameliorates diabetic renal fibrosis through inhibiting TGF-β1 signaling pathway. To identify the role of KCa3.1 in dysfunctional tubular autophagy in diabetic nephropathy, human proximal tubular cells (HK2) transfected with scrambled or KCa3.1 siRNAs were exposed to TGF-β1 for 48 h, then autophagosome formation, the autophagy marker LC3, signaling molecules PI3K, Akt and mTOR, and oxidative stress marker nitrotyrosine were examined respectively. In vivo, LC3, nitrotyrosine and phosphorylated mTOR were examined in kidneys of diabetic KCa3.1+/+ and KCa3.1-/- mice. The results demonstrated that TGF-β1 increased the formation of autophagic vacuoles, LC3 expression, and phosphorylation of PI3K, Akt and mTOR in scrambled siRNA transfected HK2 cells compared to control cells, which was reversed in KCa3.1 siRNA transfected HK2 cells. In vivo, expression of LC3 and nitrotyrosine, and phosphorylation of mTOR were significantly increased in kidneys of diabetic KCa3.1+/+ mice compared to non-diabetic mice, which were attenuated in kidneys of diabetic KCa3.1-/- mice. These results suggest that KCa3.1 activation contributes to dysfunctional tubular autophagy in diabetic nephropathy through PI3K/Akt/mTOR signaling pathways.
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Ohya S, Kito H, Hatano N, Muraki K. Recent advances in therapeutic strategies that focus on the regulation of ion channel expression. Pharmacol Ther 2016; 160:11-43. [PMID: 26896566 DOI: 10.1016/j.pharmthera.2016.02.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A number of different ion channel types are involved in cell signaling networks, and homeostatic regulatory mechanisms contribute to the control of ion channel expression. Profiling of global gene expression using microarray technology has recently provided novel insights into the molecular mechanisms underlying the homeostatic and pathological control of ion channel expression. It has demonstrated that the dysregulation of ion channel expression is associated with the pathogenesis of neural, cardiovascular, and immune diseases as well as cancers. In addition to the transcriptional, translational, and post-translational regulation of ion channels, potentially important evidence on the mechanisms controlling ion channel expression has recently been accumulated. The regulation of alternative pre-mRNA splicing is therefore a novel therapeutic strategy for the treatment of dominant-negative splicing disorders. Epigenetic modification plays a key role in various pathological conditions through the regulation of pluripotency genes. Inhibitors of pre-mRNA splicing and histone deacetyalase/methyltransferase have potential as potent therapeutic drugs for cancers and autoimmune and inflammatory diseases. Moreover, membrane-anchoring proteins, lysosomal and proteasomal degradation-related molecules, auxiliary subunits, and pharmacological agents alter the protein folding, membrane trafficking, and post-translational modifications of ion channels, and are linked to expression-defect channelopathies. In this review, we focused on recent insights into the transcriptional, spliceosomal, epigenetic, and proteasomal regulation of ion channel expression: Ca(2+) channels (TRPC/TRPV/TRPM/TRPA/Orai), K(+) channels (voltage-gated, KV/Ca(2+)-activated, KCa/two-pore domain, K2P/inward-rectifier, Kir), and Ca(2+)-activated Cl(-) channels (TMEM16A/TMEM16B). Furthermore, this review highlights expression of these ion channels in expression-defect channelopathies.
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Affiliation(s)
- Susumu Ohya
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
| | - Hiroaki Kito
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
| | - Noriyuki Hatano
- Laboratory of Cellular Pharmacology, School of Pharmacy, Aichi-Gakuin University, Nagoya 464-8650, Japan
| | - Katsuhiko Muraki
- Laboratory of Cellular Pharmacology, School of Pharmacy, Aichi-Gakuin University, Nagoya 464-8650, Japan.
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A novel adipokine C1q/TNF-related protein 3 is expressed in developing skeletal muscle and controls myoblast proliferation and differentiation. Mol Cell Biochem 2015; 409:271-82. [DOI: 10.1007/s11010-015-2531-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 08/06/2015] [Indexed: 01/08/2023]
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Abstract
PURPOSE OF REVIEW Hypertension and hyperglycaemia are major risk factors that result in chronic kidney disease (CKD). Achievement of blood pressure goals, optimal control of blood glucose levels and the use of agents to block the renin-angiotensin-aldosterone system slow the progression of CKD. However, not all patients are benefited by these interventions and novel strategies to arrest or reverse the pathological processes inherent in CKD are needed. The therapeutic potential of targeting KCa3.1 in CKD will be discussed in this review. RECENT FINDINGS Blockade of KCa3.1 ameliorates activation of renal fibroblasts in diabetic mice by inhibiting the transforming growth factor-β1/small mothers against decapentaplegic pathway. A concomitant reduction in nuclear factor-κB activation in human proximal tubular cells under diabetic conditions has been observed. Advanced glycosylated endproducts induce both protein expression and current density of KCa3.1, which, in turn, mediates migration and proliferation of vascular smooth muscle cells via Ca²⁺-dependent signalling pathways. SUMMARY Studies have clearly demonstrated a causal role of chronic hyperglycaemia and hypertension in the development of CKD. However, a large proportion of patients develop end-stage kidney disease despite strict glycaemic control and the attainment of recommended blood pressure goals. Therefore, it is essential to identify and validate novel targets to reduce the development and progression of CKD. Recent findings demonstrate that genetic deletion or pharmacologic inhibition of KCa3.1 significantly reduces the development of diabetic nephropathy in animal models. However, the consequences of blockade of KCa3.1 in preventing and treating established diabetic nephropathy in humans warrants further study.
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Zhou XB, Feng YX, Sun Q, Lukowski R, Qiu Y, Spiger K, Li Z, Ruth P, Korth M, Skolnik EY, Borggrefe M, Dobrev D, Wieland T. Nucleoside diphosphate kinase B-activated intermediate conductance potassium channels are critical for neointima formation in mouse carotid arteries. Arterioscler Thromb Vasc Biol 2015; 35:1852-61. [PMID: 26088577 DOI: 10.1161/atvbaha.115.305881] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 05/29/2015] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Vascular smooth muscle cells (VSMC) proliferation is a hallmark of atherosclerosis and vascular restenosis. The intermediate conductance Ca(2+)-activated K(+) (SK4) channel is required for pathological VSMC proliferation. In T lymphocytes, nucleoside diphosphate kinase B (NDPKB) has been implicated in SK4 channel activation. We thus investigated the role of NDPKB in the regulation of SK4 currents (ISK4) in proliferating VSMC and neointima formation. APPROACH AND RESULTS Function and expression of SK4 channels in VSMC from injured mouse carotid arteries were assessed by patch-clamping and real-time polymerase chain reaction. ISK4 was detectable in VSMC from injured but not from uninjured arteries correlating with the occurrence of the proliferative phenotype. Direct application of NDPKB to the membrane of inside-out patches increased ISK4, whereas NDPKB did not alter currents in VSMC obtained from injured vessels of SK4-deficient mice. The NDPKB-induced increase in ISK4 was prevented by protein histidine phosphatase 1, but not an inactive protein histidine phosphatase 1 mutant indicating that ISK4 is regulated via histidine phosphorylation in proliferating VSMC; moreover, genetic NDPKB ablation reduced ISK4 by 50% suggesting a constitutive activation of ISK4 in proliferating VSMC. In line, neointima formation after wire injury of the carotid artery was substantially reduced in mice deficient in SK4 channels or NDPKB. CONCLUSIONS NDPKB to SK4 signaling is required for neointima formation. Constitutive activation of SK4 by NDPKB in proliferating VSMC suggests that targeting this interaction via, for example, activation of protein histidine phosphatase 1 may provide clinically meaningful effects in vasculoproliferative diseases such as atherosclerosis and post angioplasty restenosis.
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Affiliation(s)
- Xiao-Bo Zhou
- From the 1st Medical Clinic (X.B.-Z., M.B.), Institute of Experimental and Clinical Pharmacology and Toxicology (Y.-X.F., Y.Q., K.S., T.W.), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; Institute of Pharmacology, West German Heart and Vessel Centre, University Duisburg-Essen, Essen, Germany (Q.S., D.D.); Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany (R.L., P.R.); Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (M.K.); Department of Medicine (Z.L., E.Y.S.) and Department of Pharmacology (Z.L., E.Y.S.), Langone Medical Center, New York University; and DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg-Mannheim, Germany (M.B., T.W.)
| | - Yu-Xi Feng
- From the 1st Medical Clinic (X.B.-Z., M.B.), Institute of Experimental and Clinical Pharmacology and Toxicology (Y.-X.F., Y.Q., K.S., T.W.), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; Institute of Pharmacology, West German Heart and Vessel Centre, University Duisburg-Essen, Essen, Germany (Q.S., D.D.); Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany (R.L., P.R.); Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (M.K.); Department of Medicine (Z.L., E.Y.S.) and Department of Pharmacology (Z.L., E.Y.S.), Langone Medical Center, New York University; and DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg-Mannheim, Germany (M.B., T.W.)
| | - Qiang Sun
- From the 1st Medical Clinic (X.B.-Z., M.B.), Institute of Experimental and Clinical Pharmacology and Toxicology (Y.-X.F., Y.Q., K.S., T.W.), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; Institute of Pharmacology, West German Heart and Vessel Centre, University Duisburg-Essen, Essen, Germany (Q.S., D.D.); Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany (R.L., P.R.); Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (M.K.); Department of Medicine (Z.L., E.Y.S.) and Department of Pharmacology (Z.L., E.Y.S.), Langone Medical Center, New York University; and DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg-Mannheim, Germany (M.B., T.W.)
| | - Robert Lukowski
- From the 1st Medical Clinic (X.B.-Z., M.B.), Institute of Experimental and Clinical Pharmacology and Toxicology (Y.-X.F., Y.Q., K.S., T.W.), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; Institute of Pharmacology, West German Heart and Vessel Centre, University Duisburg-Essen, Essen, Germany (Q.S., D.D.); Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany (R.L., P.R.); Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (M.K.); Department of Medicine (Z.L., E.Y.S.) and Department of Pharmacology (Z.L., E.Y.S.), Langone Medical Center, New York University; and DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg-Mannheim, Germany (M.B., T.W.)
| | - Yi Qiu
- From the 1st Medical Clinic (X.B.-Z., M.B.), Institute of Experimental and Clinical Pharmacology and Toxicology (Y.-X.F., Y.Q., K.S., T.W.), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; Institute of Pharmacology, West German Heart and Vessel Centre, University Duisburg-Essen, Essen, Germany (Q.S., D.D.); Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany (R.L., P.R.); Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (M.K.); Department of Medicine (Z.L., E.Y.S.) and Department of Pharmacology (Z.L., E.Y.S.), Langone Medical Center, New York University; and DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg-Mannheim, Germany (M.B., T.W.)
| | - Katharina Spiger
- From the 1st Medical Clinic (X.B.-Z., M.B.), Institute of Experimental and Clinical Pharmacology and Toxicology (Y.-X.F., Y.Q., K.S., T.W.), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; Institute of Pharmacology, West German Heart and Vessel Centre, University Duisburg-Essen, Essen, Germany (Q.S., D.D.); Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany (R.L., P.R.); Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (M.K.); Department of Medicine (Z.L., E.Y.S.) and Department of Pharmacology (Z.L., E.Y.S.), Langone Medical Center, New York University; and DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg-Mannheim, Germany (M.B., T.W.)
| | - Zhai Li
- From the 1st Medical Clinic (X.B.-Z., M.B.), Institute of Experimental and Clinical Pharmacology and Toxicology (Y.-X.F., Y.Q., K.S., T.W.), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; Institute of Pharmacology, West German Heart and Vessel Centre, University Duisburg-Essen, Essen, Germany (Q.S., D.D.); Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany (R.L., P.R.); Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (M.K.); Department of Medicine (Z.L., E.Y.S.) and Department of Pharmacology (Z.L., E.Y.S.), Langone Medical Center, New York University; and DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg-Mannheim, Germany (M.B., T.W.)
| | - Peter Ruth
- From the 1st Medical Clinic (X.B.-Z., M.B.), Institute of Experimental and Clinical Pharmacology and Toxicology (Y.-X.F., Y.Q., K.S., T.W.), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; Institute of Pharmacology, West German Heart and Vessel Centre, University Duisburg-Essen, Essen, Germany (Q.S., D.D.); Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany (R.L., P.R.); Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (M.K.); Department of Medicine (Z.L., E.Y.S.) and Department of Pharmacology (Z.L., E.Y.S.), Langone Medical Center, New York University; and DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg-Mannheim, Germany (M.B., T.W.)
| | - Michael Korth
- From the 1st Medical Clinic (X.B.-Z., M.B.), Institute of Experimental and Clinical Pharmacology and Toxicology (Y.-X.F., Y.Q., K.S., T.W.), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; Institute of Pharmacology, West German Heart and Vessel Centre, University Duisburg-Essen, Essen, Germany (Q.S., D.D.); Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany (R.L., P.R.); Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (M.K.); Department of Medicine (Z.L., E.Y.S.) and Department of Pharmacology (Z.L., E.Y.S.), Langone Medical Center, New York University; and DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg-Mannheim, Germany (M.B., T.W.)
| | - Edward Y Skolnik
- From the 1st Medical Clinic (X.B.-Z., M.B.), Institute of Experimental and Clinical Pharmacology and Toxicology (Y.-X.F., Y.Q., K.S., T.W.), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; Institute of Pharmacology, West German Heart and Vessel Centre, University Duisburg-Essen, Essen, Germany (Q.S., D.D.); Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany (R.L., P.R.); Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (M.K.); Department of Medicine (Z.L., E.Y.S.) and Department of Pharmacology (Z.L., E.Y.S.), Langone Medical Center, New York University; and DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg-Mannheim, Germany (M.B., T.W.)
| | - Martin Borggrefe
- From the 1st Medical Clinic (X.B.-Z., M.B.), Institute of Experimental and Clinical Pharmacology and Toxicology (Y.-X.F., Y.Q., K.S., T.W.), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; Institute of Pharmacology, West German Heart and Vessel Centre, University Duisburg-Essen, Essen, Germany (Q.S., D.D.); Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany (R.L., P.R.); Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (M.K.); Department of Medicine (Z.L., E.Y.S.) and Department of Pharmacology (Z.L., E.Y.S.), Langone Medical Center, New York University; and DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg-Mannheim, Germany (M.B., T.W.)
| | - Dobromir Dobrev
- From the 1st Medical Clinic (X.B.-Z., M.B.), Institute of Experimental and Clinical Pharmacology and Toxicology (Y.-X.F., Y.Q., K.S., T.W.), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; Institute of Pharmacology, West German Heart and Vessel Centre, University Duisburg-Essen, Essen, Germany (Q.S., D.D.); Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany (R.L., P.R.); Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (M.K.); Department of Medicine (Z.L., E.Y.S.) and Department of Pharmacology (Z.L., E.Y.S.), Langone Medical Center, New York University; and DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg-Mannheim, Germany (M.B., T.W.)
| | - Thomas Wieland
- From the 1st Medical Clinic (X.B.-Z., M.B.), Institute of Experimental and Clinical Pharmacology and Toxicology (Y.-X.F., Y.Q., K.S., T.W.), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; Institute of Pharmacology, West German Heart and Vessel Centre, University Duisburg-Essen, Essen, Germany (Q.S., D.D.); Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany (R.L., P.R.); Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (M.K.); Department of Medicine (Z.L., E.Y.S.) and Department of Pharmacology (Z.L., E.Y.S.), Langone Medical Center, New York University; and DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg-Mannheim, Germany (M.B., T.W.).
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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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18
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Abstract
There is an urgent need to identify novel interventions for mitigating the progression of diabetic nephropathy. Diabetic nephropathy is characterized by progressive renal fibrosis, in which tubulointerstitial fibrosis has been shown to be the final common pathway of all forms of chronic progressive renal disease, including diabetic nephropathy. Therefore targeting the possible mechanisms that drive this process may provide novel therapeutics which allow the prevention and potentially retardation of the functional decline in diabetic nephropathy. Recently, the Ca2+-activated K+ channel KCa3.1 (KCa3.1) has been suggested as a potential therapeutic target for nephropathy, based on its ability to regulate Ca2+ entry into cells and modulate Ca2+-signalling processes. In the present review, we focus on the physiological role of KCa3.1 in those cells involved in the tubulointerstitial fibrosis, including proximal tubular cells, fibroblasts, inflammatory cells (T-cells and macrophages) and endothelial cells. Collectively these studies support further investigation into KCa3.1 as a therapeutic target in diabetic nephropathy.
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Chubinskiy-Nadezhdin VI, Negulyaev YA, Morachevskaya EA. Functional coupling of ion channels in cellular mechanotransduction. Biochem Biophys Res Commun 2014; 451:421-4. [DOI: 10.1016/j.bbrc.2014.07.131] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Accepted: 07/30/2014] [Indexed: 10/24/2022]
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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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The Ca²⁺-activated K⁺ channel KCa3.1 as a potential new target for the prevention of allograft vasculopathy. PLoS One 2013; 8:e81006. [PMID: 24312257 PMCID: PMC3843675 DOI: 10.1371/journal.pone.0081006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 10/09/2013] [Indexed: 12/13/2022] Open
Abstract
Allograft vasculopathy (AV) remains one of the major challenges to the long-term functioning of solid organ transplants. Although its exact pathogenesis remains unclear, AV is characterized by both fibromuscular proliferation and infiltration of CD4+ memory T cells. We here tested whether two experimental immunosuppressants targeting K+ channels might be useful for preventing AV. PAP-1 inhibits the voltage-gated Kv1.3 channel, which is overexpressed on CCR7− memory T cells and we therefore hypothesize that it should suppress the memory T cell component of AV. Based on its previous efficacy in restenosis and kidney fibrosis we expected that the KCa3.1 blocker TRAM-34 would primarily affect smooth muscle and fibroblast proliferation and thus reduce intimal hyperplasia. Using immunohistochemistry we demonstrated the presence of Kv1.3 on infiltrating T cells and of KCa3.1 on lymphocytes as well as on proliferating neointimal smooth muscle cells in human vasculopathy samples and in a rat aorta transplant model developing chronic AV. Treatment of PVG rats receiving orthotopically transplanted aortas from ACI rats with TRAM-34 dose-dependently reduced aortic luminal occlusion, intimal hyperplasia, mononuclear cell infiltration and collagen deposition 120 days after transplantation. The Kv1.3 blocker PAP-1 in contrast did not reduce intima hyperplasia despite drastically reducing plasma IFN-γ levels and inhibiting lymphocyte infiltration. Our findings suggest that KCa3.1 channels play an important role in the pathogenesis of chronic AV and constitute an attractive target for the prevention of arteriopathy.
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Endothelial small-conductance and intermediate-conductance KCa channels: an update on their pharmacology and usefulness as cardiovascular targets. J Cardiovasc Pharmacol 2013; 61:102-12. [PMID: 23107876 DOI: 10.1097/fjc.0b013e318279ba20] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Most cardiovascular researchers are familiar with intermediate-conductance KCa3.1 and small-conductance KCa2.3 channels because of their contribution to endothelium-derived hyperpolarization. However, to immunologists and neuroscientists, these channels are primarily known for their role in lymphocyte activation and neuronal excitability. KCa3.1 is involved in the proliferation and migration of T cells, B cells, mast cells, macrophages, fibroblasts, and dedifferentiated vascular smooth muscle cells and is, therefore, being pursued as a potential target for use in asthma, immunosuppression, and fibroproliferative disorders. In contrast, the 3 KCa2 channels (KCa2.1, KCa2.2, and KCa2.3) contribute to the neuronal medium afterhyperpolarization and, depending on the type of neuron, are involved in determining firing rates and frequencies or in regulating bursting. KCa2 activators are accordingly being studied as potential therapeutics for ataxia and epilepsy, whereas KCa2 channel inhibitors like apamin have long been known to improve learning and memory in rodents. Given this background, we review the recent discoveries of novel KCa3.1 and KCa2.3 modulators and critically assess the potential of KCa activators for the treatment of diabetes and cardiovascular diseases by improving endothelium-derived hyperpolarizations.
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Frede J, Fraser SP, Oskay-Özcelik G, Hong Y, Ioana Braicu E, Sehouli J, Gabra H, Djamgoz MB. Ovarian cancer: Ion channel and aquaporin expression as novel targets of clinical potential. Eur J Cancer 2013; 49:2331-44. [DOI: 10.1016/j.ejca.2013.03.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Revised: 01/29/2013] [Accepted: 03/10/2013] [Indexed: 01/11/2023]
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Takai J, Santu A, Zheng H, Koh SD, Ohta M, Filimban LM, Lemaître V, Teraoka R, Jo H, Miura H. Laminar shear stress upregulates endothelial Ca²⁺-activated K⁺ channels KCa2.3 and KCa3.1 via a Ca²⁺/calmodulin-dependent protein kinase kinase/Akt/p300 cascade. Am J Physiol Heart Circ Physiol 2013; 305:H484-93. [PMID: 23792675 DOI: 10.1152/ajpheart.00642.2012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In endothelial cells (ECs), Ca²⁺-activated K⁺ channels KCa2.3 and KCa3.1 play a crucial role in the regulation of arterial tone via producing NO and endothelium-derived hyperpolarizing factors. Since a rise in intracellular Ca²⁺ levels and activation of p300 histone acetyltransferase are early EC responses to laminar shear stress (LS) for the transcriptional activation of genes, we examined the role of Ca²⁺/calmodulin-dependent kinase kinase (CaMKK), the most upstream element of a Ca²⁺/calmodulin-kinase cascade, and p300 in LS-dependent regulation of KCa2.3 and KCa3.1 in ECs. Exposure to LS (15 dyn/cm²) for 24 h markedly increased KCa2.3 and KCa3.1 mRNA expression in cultured human coronary artery ECs (3.2 ± 0.4 and 45 ± 10 fold increase, respectively; P < 0.05 vs. static condition; n = 8-30), whereas oscillatory shear (OS; ± 5 dyn/cm² × 1 Hz) moderately increased KCa3.1 but did not affect KCa2.3. Expression of KCa2.1 and KCa2.2 was suppressed under both LS and OS conditions, whereas KCa1.1 was slightly elevated in LS and unchanged in OS. Inhibition of CaMKK attenuated LS-induced increases in the expression and channel activity of KCa2.3 and KCa3.1, and in phosphorylation of Akt (Ser473) and p300 (Ser1834). Inhibition of Akt abolished the upregulation of these channels by diminishing p300 phosphorylation. Consistently, disruption of the interaction of p300 with transcription factors eliminated the induction of these channels. Thus a CaMKK/Akt/p300 cascade plays an important role in LS-dependent induction of KCa2.3 and KCa3.1 expression, thereby regulating EC function and adaptation to hemodynamic changes.
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Affiliation(s)
- Jun Takai
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
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Yang H, Li X, Ma J, Lv X, Zhao S, Lang W, Zhang Y. Blockade of the intermediate-conductance Ca(2+)-activated K+ channel inhibits the angiogenesis induced by epidermal growth factor in the treatment of corneal alkali burn. Exp Eye Res 2013; 110:76-87. [PMID: 23482085 DOI: 10.1016/j.exer.2013.02.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 02/17/2013] [Accepted: 02/21/2013] [Indexed: 12/29/2022]
Abstract
Epidermal growth factor (EGF) is used to treat alkali-burned corneas. However, EGF-induced corneal angiogenesis, which is currently untreatable, is a side effect of this therapy. We therefore explored the role of the intermediate-conductance Ca(2+)-activated K(+) channel (KCa3.1) in EGF-induced angiogenesis and tested whether KCa3.1 blockade can suppress EGF-induced corneal angiogenesis. The proliferation, migration and tube formation of HUVECs (human umbilical vein endothelial cells) in response to EGF, the MEK inhibitor PD98059 and the KCa3.1 inhibitor TRAM-34 were analyzed in vitro via MTT, cell counting, scratch and tube formation assays. The protein and mRNA levels of KCa3.1, phosphorylated-ERK (P-ERK), total-ERK (T-ERK), cyclin-dependent kinase 4 (CDK4), vimentin and MMP-2 were assessed via western blotting and RT-PCR. KCa3.1 and vimentin expression were also detected through immunofluorescence staining. Flow cytometry was performed to examine the cell cycle. Further, an in vivo murine alkali-burned cornea model was developed and treated with EGF and TRAM-34 eye drops to analyze the effect of these treatments on corneal healing and angiogenesis. The corneas were also analyzed by histological staining. The in vitro results showed that EGF induces the upregulation of KCa3.1 and P-ERK in HUVECs and that this upregulation is suppressed by PD98059. EGF stimulates proliferation, migration and tube formation in HUVECs, and this effect can be suppressed by TRAM-34. TRAM-34 also arrests HUVECs in the G1 phase of the cell cycle and downregulates CDK4, vimentin and MMP-2 in these cells. The in vivo results indicated that TRAM-34 suppresses EGF-induced corneal angiogenesis without affecting EGF-induced corneal wound healing. In summary, the upregulation of KCa3.1 may be crucial for EGF-induced angiogenesis through the MAPK/ERK signaling pathway. Thus, KCa3.1 may be a potential target for the treatment of EGF-induced corneal angiogenesis.
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Affiliation(s)
- Huike Yang
- Department of Anatomy, Harbin Medical University, Harbin 150081, China
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Yang XW, Liu JW, Zhang RC, Yin Q, Shen WZ, Yi JL. Inhibitory effects of blockage of intermediate conductance Ca(2+)-activated K (+) channels on proliferation of hepatocellular carcinoma cells. ACTA ACUST UNITED AC 2013; 33:86-89. [PMID: 23392713 DOI: 10.1007/s11596-013-1076-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Indexed: 01/22/2023]
Abstract
The roles of intermediate conductance Ca(2+)-activated K(+) channel (IKCa1) in the pathogenesis of hepatocellular carcinoma (HCC) were investigated. Immunohistochemistry and Western blotting were used to detect the expression of IKCa1 protein in 50 HCC and 20 para-carcinoma tissue samples. Real-time PCR was used to detect the transcription level of IKCa1 mRNA in 13 HCC and 11 para-carcinoma tissue samples. The MTT assay was used to measure the function of IKCa1 in human HCC cell line HepG2 in vitro. TRAM-34, a specific blocker of IKCa1, was used to intervene with the function of IKCa1. As compared with para-carcinoma tissue, an over-expression of IKCa1 protein was detected in HCC tissue samples (P<0.05). The mRNA expression level of IKCa1 in HCC tissues was 2.17 times higher than that in para-carcinoma tissues. The proliferation of HepG2 cells was suppressed by TRAM-34 (0.5, 1.0, 2.0 and 4.0 μmol/L) in vitro (P<0.05). Our results suggested that IKCa1 may play a role in the proliferation of human HCC, and IKCa1 blockers may represent a potential therapeutic strategy for HCC.
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Affiliation(s)
- Xiao-Wei Yang
- Department of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Jin-Wen Liu
- Department of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
| | - Ru-Chao Zhang
- Department of General Surgery, Yichang Central People's Hospital, the First College of Clinical Medical Science, China Three Gorges University, Yichang, 443003, China
| | - Qian Yin
- Department of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Wen-Zhuang Shen
- Department of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Ji-Lin Yi
- Department of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
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Absi MF, Edwards G, Weston AH. Expression and function of calcium-activated potassium channels following in-stent restenosis in a porcine coronary artery model. J Adv Res 2012. [DOI: 10.1016/j.jare.2011.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Wulff H, Castle NA. Therapeutic potential of KCa3.1 blockers: recent advances and promising trends. Expert Rev Clin Pharmacol 2012; 3:385-96. [PMID: 22111618 DOI: 10.1586/ecp.10.11] [Citation(s) in RCA: 144] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The Ca(2+)-activated K(+) channel K(Ca)3.1 regulates membrane potential and calcium signaling in erythrocytes, activated T and B cells, macrophages, microglia, vascular endothelium, epithelia, and proliferating vascular smooth muscle cells and fibroblasts. K(Ca)3.1 has therefore been suggested as a potential therapeutic target for diseases such as sickle cell anemia, asthma, coronary restenosis after angioplasty, atherosclerosis, kidney fibrosis and autoimmunity, where activation and excessive proliferation of one or more of these cell types is involved in the pathology. This article will review the physiology and pharmacology of K(Ca)3.1 and critically examine the available preclinical and clinical data validating K(Ca)3.1 as a therapeutic target.
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The KCa3.1 blocker TRAM-34 reduces infarction and neurological deficit in a rat model of ischemia/reperfusion stroke. J Cereb Blood Flow Metab 2011; 31:2363-74. [PMID: 21750563 PMCID: PMC3323185 DOI: 10.1038/jcbfm.2011.101] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Microglia and brain infiltrating macrophages significantly contribute to the secondary inflammatory damage in the wake of ischemic stroke. Here, we investigated whether inhibition of KCa3.1 (IKCa1/KCNN4), a calcium-activated K(+) channel that is involved in microglia and macrophage activation and expression of which increases on microglia in the infarcted area, has beneficial effects in a rat model of ischemic stroke. Using an HPLC/MS assay, we first confirmed that our small molecule KCa3.1 blocker TRAM-34 effectively penetrates into the brain and achieves micromolar plasma and brain concentrations after intraperitoneal injection. Then, we subjected male Wistar rats to 90 minutes of middle cerebral artery occlusion (MCAO) and administered either vehicle or TRAM-34 (10 or 40 mg/kg intraperitoneally twice daily) for 7 days starting 12 hours after reperfusion. Both compound doses reduced infarct area by ≈ 50% as determined by hematoxylin & eosin staining on day 7 and the higher dose also significantly improved neurological deficit. We further observed a significant reduction in ED1(+)-activated microglia and TUNEL-positive neurons as well as increases in NeuN(+) neurons in the infarcted hemisphere. Our findings suggest that KCa3.1 blockade constitutes an attractive approach for the treatment of ischemic stroke because it is still effective when initiated 12 hours after the insult.
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Lam J, Wulff H. The Lymphocyte Potassium Channels Kv1.3 and KCa3.1 as Targets for Immunosuppression. Drug Dev Res 2011; 72:573-584. [PMID: 22241939 PMCID: PMC3253536 DOI: 10.1002/ddr.20467] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The voltage-gated Kv1.3 and the calcium-activated KCa3.1 potassium channel modulate many calcium-dependent cellular processes in immune cells, including T-cell activation and proliferation, and have therefore been proposed as novel therapeutic targets for immunomodulation. Kv1.3 is highly expressed in CCR7(-) effector memory T cells and is emerging as a target for T-cell mediated diseases like multiple sclerosis, rheumatoid arthritis, type-1 diabetes mellitus, allergic contact dermatitis, and psoriasis. KCa3.1 in contrast is expressed in CCR7(+) naïve and central memory T cells, as well as in mast cells, macrophages, dedifferentiated vascular smooth muscle cells, fibroblasts, vascular endothelium, and airway epithelium. Given this expression pattern, KCa3.1 is a potential therapeutic target for conditions ranging from inflammatory bowel disease, multiple sclerosis, arthritis, and asthma to cardiovascular diseases like atherosclerosis and post-angioplasty restenosis. Results from animal studies have been supportive of the therapeutic potential of both Kv1.3 and KCa3.1 blockers and have also not shown any toxicities associated with pharmacological Kv1.3 and KCa3.1 blockade. To date, two compounds targeting Kv1.3 are in preclinical development but, so far, no Kv1.3 blocker has advanced into clinical trials. KCa3.1 blockers, on the other hand, have been evaluated in clinical trials for sickle cell anemia and exercise-induced asthma, but have so far not shown efficacy. However, the trial results support KCa3.1 as a safe therapeutic target, and will hopefully help enable clinical trials for other medical conditions that might benefit from KCa3.1 blockade.
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Affiliation(s)
- Jenny Lam
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA
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31
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The myogenic kinome: protein kinases critical to mammalian skeletal myogenesis. Skelet Muscle 2011; 1:29. [PMID: 21902831 PMCID: PMC3180440 DOI: 10.1186/2044-5040-1-29] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 09/08/2011] [Indexed: 12/13/2022] Open
Abstract
Myogenesis is a complex and tightly regulated process, the end result of which is the formation of a multinucleated myofibre with contractile capability. Typically, this process is described as being regulated by a coordinated transcriptional hierarchy. However, like any cellular process, myogenesis is also controlled by members of the protein kinase family, which transmit and execute signals initiated by promyogenic stimuli. In this review, we describe the various kinases involved in mammalian skeletal myogenesis: which step of myogenesis a particular kinase regulates, how it is activated (if known) and what its downstream effects are. We present a scheme of protein kinase activity, similar to that which exists for the myogenic transcription factors, to better clarify the complex signalling that underlies muscle development.
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Waschk DEJ, Fabian A, Budde T, Schwab A. Dual-color quantum dot detection of a heterotetrameric potassium channel (hKCa3.1). Am J Physiol Cell Physiol 2011; 300:C843-9. [PMID: 21228320 DOI: 10.1152/ajpcell.00053.2010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Potassium channels play a key role in establishing the cell membrane potential and are expressed ubiquitously. Today, more than 70 mammalian K(+) channel genes are known. The diversity of K(+) channels is further increased by the fact that different K(+) channel family members may assemble to form heterotetramers. We present a method based on fluorescence microscopy to determine the subunit composition of a tetrameric K(+) channel. We generated artificial "heteromers" of the K(+) channel hK(Ca)3.1 by coexpressing two differently tagged hK(Ca)3.1 constructs containing either an extracellular hemagglutinin (HA) or an intracellular V5 epitope. hK(Ca)3.1 channel subunits were detected in the plasma membrane of MDCK-F cells or HEK293 cells by labeling the extra- and intracellular epitopes with differently colored quantum dots (QDs). As previously shown for the extracellular part of hK(Ca)3.1 channels, its intracellular domain can also bind only one QD label at a time. When both channel subunits were coexpressed, 27.5 ± 1.8% and 24.9 ± 2.1% were homotetramers consisting of HA- and V5-tagged subunits, respectively. 47.6 ± 3.2% of the channels were heteromeric and composed of both subunits. The frequency distribution of HA- and V5-tagged homo- and heteromeric hK(Ca)3.1 channels is reminiscent of the binomial distribution (a + b)(2) = a(2) + 2ab + b(2). Along these lines, our findings are consistent with the notion that hK(Ca)3.1 channels are assembled from two homomeric dimers and not randomly from four independent subunits. We anticipate that our technique will be applicable to other heteromeric membrane proteins, too.
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Reduced expression of SK3 and IK1 channel proteins in the cavernous tissue of diabetic rats. Asian J Androl 2010; 12:599-604. [PMID: 20364152 DOI: 10.1038/aja.2009.97] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The small (SK3) and intermediate (IK1) conductance calcium-activated potassium channels could have key roles in the endothelium-dependent hyperpolarization factor pathway, which is believed to contribute to normal penile erection function. We aimed to investigate the expression of SK3 and IK1 in diabetic rodents. The experimental diabetes model was induced in 8-week-old male Sprague-Dawley rats (250-300 g) by a single administration of streptozotocin. Both the diabetes mellitus group (DM group, n = 20) and the control group (NDM group, n = 10) were injected with a low dose of apomorphine to allow for the measurement and comparison of the corresponding penile erections. The mRNA and protein expression levels of SK3 and IK1 were measured by reverse transcription polymerase chain reaction and western blot, respectively. Erectile function was significantly decreased in the DM group compared with control group (P < 0.05). The mRNA and protein expression levels of SK3 and IK1 were reduced in the cavernous tissue of diabetic rats compared with the control group (P < 0.05). Diabetes inhibits mRNA and protein expression of both SK3 and IK1 in the cavernous tissue of diabetic rats. This could play a key role in the development of erectile dysfunction in diabetic rats.
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34
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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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Aziz A, Miyake T, Engleka KA, Epstein JA, McDermott JC. Menin expression modulates mesenchymal cell commitment to the myogenic and osteogenic lineages. Dev Biol 2009; 332:116-30. [PMID: 19464283 DOI: 10.1016/j.ydbio.2009.05.555] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Revised: 05/09/2009] [Accepted: 05/15/2009] [Indexed: 10/20/2022]
Abstract
Menin plays an established role in the differentiation of mesenchymal cells to the osteogenic lineage. Conversely, whether Menin influences the commitment of mesenschymal cells to the myogenic lineage, despite expression in the developing somite was previously unclear. We observed that Menin is down-regulated in C2C12 and C3H10T1/2 mesenchymal cells when muscle differentiation is induced. Moreover, maintenance of Menin expression by constitutive ectopic expression inhibited muscle cell differentiation. Reduction of Menin expression by siRNA technology results in precocious muscle differentiation and concomitantly attenuates BMP-2 induced osteogenesis. Reduced Menin expression antagonizes BMP-2 and TGF-beta1 mediated inhibition of myogenesis. Furthermore, Menin was found to directly interact with and potentiate the transactivation properties of Smad3 in response to TGF-beta1. Finally in concert with these observations, tissue-specific inactivation of Men1 in Pax3-expressing somite precursor cells leads to a patterning defect of rib formation and increased muscle mass in the intercostal region. These data invoke a pivotal role for Menin in the competence of mesenchymal cells to respond to TGF-beta1 and BMP-2 signals. Thus, by modulating cytokine responsiveness Menin functions to alter the balance of multipotent mesenchymal cell commitment to the osteogenic or myogenic lineages.
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Affiliation(s)
- Arif Aziz
- Department of Biology, 327 Farquharson, LSB, York University, Toronto, M3J 1P3 Ontario, Canada
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36
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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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37
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Nardi A, Demnitz J, Garcia ML, Polosa R. Potassium channels as drug targets for therapeutic intervention in respiratory diseases. Expert Opin Ther Pat 2008. [DOI: 10.1517/13543770802553798] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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38
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McDaneld TG, Spurlock DM. Ankyrin repeat and suppressor of cytokine signaling (SOCS) box-containing protein (ASB) 15 alters differentiation of mouse C2C12 myoblasts and phosphorylation of mitogen-activated protein kinase and Akt1. J Anim Sci 2008; 86:2897-902. [DOI: 10.2527/jas.2008-1076] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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39
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Perez-Zoghbi JF, Karner C, Ito S, Shepherd M, Alrashdan Y, Sanderson MJ. Ion channel regulation of intracellular calcium and airway smooth muscle function. Pulm Pharmacol Ther 2008; 22:388-97. [PMID: 19007899 DOI: 10.1016/j.pupt.2008.09.006] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Revised: 09/03/2008] [Accepted: 09/28/2008] [Indexed: 12/11/2022]
Abstract
Airway hyper-responsiveness associated with asthma is mediated by airway smooth muscle cells (SMCs) and has a complicated etiology involving increases in cell contraction and proliferation and the secretion of inflammatory mediators. Although these pathological changes are diverse, a common feature associated with their regulation is a change in intracellular Ca(2+) concentration ([Ca(2+)](i)). Because the [Ca(2+)](i) itself is a function of the activity and expression of a variety of ion channels, in both the plasma membrane and sarcoplasmic reticulum of the SMC, the modification of this ion channel activity may predispose airway SMCs to hyper-responsiveness. Our objective is to review how ion channels determine the [Ca(2+)](i) and influence the function of airway SMCs and emphasize the potential of ion channels as sites for therapeutic approaches to asthma.
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Affiliation(s)
- Jose F Perez-Zoghbi
- Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
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40
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Sweetman D, Goljanek K, Rathjen T, Oustanina S, Braun T, Dalmay T, Münsterberg A. Specific requirements of MRFs for the expression of muscle specific microRNAs, miR-1, miR-206 and miR-133. Dev Biol 2008; 321:491-9. [PMID: 18619954 DOI: 10.1016/j.ydbio.2008.06.019] [Citation(s) in RCA: 215] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 06/11/2008] [Accepted: 06/12/2008] [Indexed: 01/11/2023]
Abstract
The expression of three microRNAs, miR-1, miR-206 and miR-133 is restricted to skeletal myoblasts and cardiac tissue during embryo development and muscle cell differentiation, which suggests a regulation by muscle regulatory factors (MRFs). Here we show that inhibition of C2C12 muscle cell differentiation by FGFs, which interferes with the activity of MRFs, suppressed the expression of miR-1, miR-206 and miR-133. To further investigate the role of myogenic regulators (MRFs), Myf5, MyoD, Myogenin and MRF4 in the regulation of muscle specific microRNAs we performed gain and loss-of-function experiments in vivo, in chicken and mouse embryos. We found that directed expression of MRFs in the neural tube of chicken embryos induced ectopic expression of miR-1 and miR-206. Conversely, the lack of Myf5 but not of MyoD resulted in a loss of miR-1 and miR-206 expression. Taken together our results demonstrate differential requirements of distinct MRFs for the induction of microRNA gene expression during skeletal myogenesis.
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Affiliation(s)
- Dylan Sweetman
- School of Biological Sciences, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK.
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41
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Wulff H, Zhorov BS. K+ channel modulators for the treatment of neurological disorders and autoimmune diseases. Chem Rev 2008; 108:1744-73. [PMID: 18476673 PMCID: PMC2714671 DOI: 10.1021/cr078234p] [Citation(s) in RCA: 168] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Heike Wulff
- Department of Pharmacology, University of California, Davis, California 95616, USA.
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42
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Activation of cell migration with fibroblast growth factor-2 requires calcium-sensitive potassium channels. Pflugers Arch 2008; 456:813-23. [DOI: 10.1007/s00424-008-0452-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Accepted: 01/11/2008] [Indexed: 01/25/2023]
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43
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McFarlane C, Hennebry A, Thomas M, Plummer E, Ling N, Sharma M, Kambadur R. Myostatin signals through Pax7 to regulate satellite cell self-renewal. Exp Cell Res 2007; 314:317-29. [PMID: 17949710 DOI: 10.1016/j.yexcr.2007.09.012] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 09/12/2007] [Accepted: 09/15/2007] [Indexed: 11/30/2022]
Abstract
Myostatin, a Transforming Growth Factor-beta (TGF-beta) super-family member, has previously been shown to negatively regulate satellite cell activation and self-renewal. However, to date the mechanism behind Myostatin function in satellite cell biology is not known. Here we show that Myostatin signals via a Pax7-dependent mechanism to regulate satellite cell self-renewal. While excess Myostatin inhibited Pax7 expression via ERK1/2 signaling, an increase in Pax7 expression was observed following both genetic inactivation and functional antagonism of Myostatin. As a result, we show that either blocking or inactivating Myostatin enhances the partitioning of the fusion-incompetent self-renewed satellite cell lineage (high Pax7 expression, low MyoD expression) from the pool of actively proliferating myogenic precursor cells. Consistent with this result, over-expression of Pax7 in C2C12 myogenic cells resulted in increased self-renewal through a mechanism which slowed both myogenic proliferation and differentiation. Taken together, these results suggest that increased expression of Pax7 promotes satellite cell self-renewal, and furthermore Myostatin may control the process of satellite cell self-renewal through regulation of Pax7. Thus we speculate that, in addition to the intrinsic factors (such as Pax7), extrinsic factors both positive and negative in nature, will play a major role in determining the stemness of skeletal muscle satellite cells.
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Affiliation(s)
- Craig McFarlane
- AgResearch, Functional Muscle Genomics, Hamilton, New Zealand
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Wang ZH, Shen B, Yao HL, Jia YC, Ren J, Feng YJ, Wang YZ. Blockage of intermediate-conductance-Ca(2+) -activated K(+) channels inhibits progression of human endometrial cancer. Oncogene 2007; 26:5107-14. [PMID: 17310992 DOI: 10.1038/sj.onc.1210308] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Potassium (K(+)) channels have been implicated in proliferation of some tumor cells. However, whether K(+) channels are important to the pathogenesis of endometrial cancer (EC) remains unknown. In the present study, we report that intermediate-conductance Ca(2+)-activated K(+) (IKCa1) channels play a critical role in the development of EC. The expression of IKCa1 at both mRNA and protein levels in EC tissues was greatly increased than that in atypical hyperplasia and normal tissues. Treatment of EC cells with clotrimazole and TRAM-34, two agents known to inhibit IKCa1 channels, suppressed the proliferation of EC cells and blocked EC cell cycle at G(0)/G(1) phase. Similarly, downregulation of IKCa1 by siRNA against IKCa1 inhibited EC cell proliferation and arrested its cell cycle at G(0)/G(1) phase. A clotrimazole-sensitive K(+) current was induced in EC cells in response to the increased Ca(2+). The current density induced by Ca(2+) was greatly reduced by clotrimazole, TRAM-34, charybdotoxin or downregulation of IKCa1 by the siRNA against IKCa1. Furthermore, TRAM-34 and clotrimazole slowed the formation in nude mice of tumor generated by injection of EC cells. Our results suggest that increased activity of IKCa1 channel is necessary for the development of EC.
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Affiliation(s)
- Z H Wang
- The Obstetrics and Gynecology Hospital of Medical Center of Fudan University, Shanghai, China
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45
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Abstract
Cardiac function is determined by the dynamic interaction of various cell types and the extracellular matrix that composes the heart. This interaction varies with the stage of development and the degree and duration of mechanical, chemical, and electrical signals between the various cell types and the ECM. Understanding how these complex signals interact at the molecular, cellular, and organ levels is critical to understanding the function of the heart under a variety of physiological and pathophysiological conditions. Quantitative approaches, both in vivo and in vitro, are essential to understand the dynamic interaction of mechanical, chemical, and electrical stimuli that govern cardiac function. The fibroblast can thus be a friend in normal function or a foe in pathophysiological conditions.
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Affiliation(s)
- Troy A Baudino
- Department of Cell and Developmental Biology and Anatomy, School of Medicine, University of South Carolina, Columbia, SC 29208, USA
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Fioretti B, Castigli E, Micheli MR, Bova R, Sciaccaluga M, Harper A, Franciolini F, Catacuzzeno L. Expression and modulation of the intermediate- conductance Ca2+-activated K+ channel in glioblastoma GL-15 cells. Cell Physiol Biochem 2006; 18:47-56. [PMID: 16914889 DOI: 10.1159/000095135] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We report here the expression and properties of the intermediate-conductance Ca(2+)-activated K(+) (IK(Ca)) channel in the GL-15 human glioblastoma cell line. Macroscopic IK(Ca) currents on GL-15 cells displayed a mean amplitude of 7.2+/-0.8 pA/pF at 0 mV, at day 1 after plating. The current was inhibited by clotrimazole (CTL, IC(50)=257 nM), TRAM-34 (IC(50)=55 nM), and charybdotoxin (CTX, IC(50)=10.3 nM). RT-PCR analysis demonstrated the expression of mRNA encoding the IK(Ca) channel in GL-15 cells. Unitary currents recorded using the inside-out configuration had a conductance of 25 pS, a K(D) for Ca(2+) of 188 nM at -100 mV, and no voltage dependence. We tested whether the IKCa channel expression in GL-15 cells could be the result of an increased ERK activity. Inhibition of the ERK pathway with the MEK antagonist PD98059 (25 muM, for 5 days) virtually suppressed the IK(Ca) current in GL-15 cells. PD98059 treatment also increased the length of cellular processes and up-regulated the astrocytic differentiative marker GFAP. A significant reduction of the IKCa current amplitude was also observed with time in culture, with mean currents of 7.17+/-0.75 pA/pF at 1-2 days, and 3.11+/-1.35 pA/pF at 5-6 days after plating. This time-dependent downregulation of the IK(Ca) current was not accompanied by changes in the ERK activity, as assessed by immunoblot analysis. Semiquantitative RT-PCR analysis demonstrated a ~35% reduction of the IK(Ca) channel mRNA resulting from ERK inhibition and a approximately 50% reduction with time in culture.
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Affiliation(s)
- Bernard Fioretti
- Dipartimento di Biologia Cellulare e Ambientale, Universita' di Perugia, CEMIN, Centro di Eccellenza "Materiali Innovativi Nanostrutturati", Universita' di Perugia, Italy.
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47
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Pietrangelo T, Fioretti B, Mancinelli R, Catacuzzeno L, Franciolini F, Fanò G, Fulle S. Extracellular guanosine-5'-triphosphate modulates myogenesis via intermediate Ca(2+)-activated K+ currents in C2C12 mouse cells. J Physiol 2006; 572:721-33. [PMID: 16455689 PMCID: PMC1780011 DOI: 10.1113/jphysiol.2005.102194] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
In this study we investigated the role of extracellular 5'-guanosine-triphosphate (GTP) on early phases of skeletal muscle differentiation using the widely used C2C12 mouse cells as a myogenic model. We show that extracellular GTP binding to specific sites activates a metabotropic cascade that leads to a transient intracellular Ca2+ mobilization, consequent activation of the intermediate Ca(2+)-activated K+ channels (IK(Ca)), and hyperpolarization of the plasma membrane. We further show that in differentiating C2C12 myoblasts GTP induces a proliferative boost, and increases the number of cells positive for the myosin heavy chain (MyHC) proteins. These effects were shown to be mediated by the IK(Ca) channel-dependent hyperpolarization, as evidenced by their disappearance when myoblasts were incubated with the IK(Ca) channel inhibitor charybdotoxin. These data give new insights into nucleotide purinergic signalling pathways, and address the role of the GTP-dependent IK(Ca) channel activation and hyperpolarization in myogenesis.
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Affiliation(s)
- Tiziana Pietrangelo
- Dipartimento Scienze del Farmaco, Istituto Interuniversitario di Miologia, Ce.S.I. Centro di Scienze dell'Invecchiamento 'University G. d'Annunzio' Foundation, via dei Vestini, I-66013 Chieti, Italy.
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48
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Si H, Grgic I, Heyken WT, Maier T, Hoyer J, Reusch HP, Köhler R. Mitogenic modulation of Ca2+ -activated K+ channels in proliferating A7r5 vascular smooth muscle cells. Br J Pharmacol 2006; 148:909-17. [PMID: 16770324 PMCID: PMC1751930 DOI: 10.1038/sj.bjp.0706793] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Modulation of Ca(2+)-activated K(+) channels (K(Ca)) has been implicated in the control of proliferation in vascular smooth muscle cells (VSMC) and other cell types. In the present study, we investigated the underlying signal transduction mechanisms leading to mitogen-induced alterations in the expression pattern of intermediate-conductance K(Ca) in VSMC. Regulation of expression of IK(Ca)/rK(Ca)3.1 and BK(Ca)/rK(Ca)1.1 in A7r5 cells, a cell line derived from rat aortic VSMC, was investigated by patch-clamp technique, quantitative RT-PCR, immunoblotting procedures, and siRNA strategy.PDGF stimulation for 2 and 48 h induced an 11- and 3.5-fold increase in rK(Ca)3.1 transcript levels resulting in a four- and seven-fold increase in IK(Ca) currents after 4 and 48 h, respectively. Upregulation of rK(Ca)3.1 transcript levels and channel function required phosphorylation of extracellular signal-regulated kinases (ERK1/2) and Ca(2+) mobilization, but not activation of p38-MAP kinase, c-Jun NH(2)-terminal kinase, protein kinase C, calcium-calmodulin kinase II and Src kinases. In contrast to rK(Ca)3.1, mRNA expression and functions of BK(Ca)/rK(Ca)1.1 were decreased by half following mitogenic stimulation. Downregulation of rK(Ca)1.1 did not require ERK1/2 phosphorylation or Ca(2+) mobilization. In an in vitro-proliferation assay, knockdown of rK(Ca)3.1 expression by siRNA completely abolished functional IK(Ca) channels and mitogenesis. Mitogen-induced upregulation of rK(Ca)3.1 expression is mediated via activation of the Raf/MEK- and ERK-signaling cascade in a Ca(2+)-dependent manner. Upregulation of rK(Ca)3.1 promotes VSMC proliferation and may thus represent a pharmacological target in cardiovascular disease states characterized by abnormal cell proliferation.
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MESH Headings
- Blotting, Western
- Calcium Signaling/drug effects
- Cell Line
- Cell Proliferation
- Extracellular Signal-Regulated MAP Kinases/physiology
- Gene Silencing/physiology
- Humans
- Mitogens/pharmacology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Patch-Clamp Techniques
- Phosphorylation
- Platelet-Derived Growth Factor/genetics
- Potassium Channels, Calcium-Activated/drug effects
- Potassium Channels, Calcium-Activated/genetics
- Proto-Oncogene Proteins c-raf/physiology
- RNA/biosynthesis
- RNA/isolation & purification
- RNA, Small Interfering/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction/genetics
- Signal Transduction/physiology
- Up-Regulation/drug effects
- p38 Mitogen-Activated Protein Kinases/metabolism
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Affiliation(s)
- Han Si
- Department of Internal Medicine-Nephrology, Philipps-Universität, Marburg 35033, Germany
| | - Ivica Grgic
- Department of Internal Medicine-Nephrology, Philipps-Universität, Marburg 35033, Germany
| | - Willm-Thomas Heyken
- Department of Internal Medicine-Nephrology, Philipps-Universität, Marburg 35033, Germany
| | - Tanja Maier
- Department of Internal Medicine-Nephrology, Philipps-Universität, Marburg 35033, Germany
| | - Joachim Hoyer
- Department of Internal Medicine-Nephrology, Philipps-Universität, Marburg 35033, Germany
| | - Hans-Peter Reusch
- Department of Clinical Pharmacology, Ruhr-Universität Bochum, Bochum 44801, Germany
| | - Ralf Köhler
- Department of Internal Medicine-Nephrology, Philipps-Universität, Marburg 35033, Germany
- Author for correspondence:
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Yang W, Chen Y, Zhang Y, Wang X, Yang N, Zhu D. Extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase pathway is involved in myostatin-regulated differentiation repression. Cancer Res 2006; 66:1320-6. [PMID: 16452185 DOI: 10.1158/0008-5472.can-05-3060] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The cytokines of transforming growth factor beta (TGF-beta) and its superfamily members are potent regulators of tumorigenesis and multiple cellular events. Myostatin is a member of TGF-beta superfamily and plays a negative role in the control of cell proliferation and differentiation. We now show that myostatin rapidly activated the extracellular signal-regulated kinase 1/2 (Erk1/2) cascade in C2C12 myoblasts. A more remarkable Erk1/2 activation stimulated by myostatin was observed in differentiating cells than proliferating cells. The results also showed that Ras was the upstream regulator and participated in myostatin-induced Erk1/2 activation because the expression of a dominant-negative Ras prevented myostatin-mediated inhibition of Erk1/2 activation and proliferation. Importantly, the myostatin-suppressed myotube fusion and differentiation marker gene expression were attenuated by blockade of Erk1/2 mitogen-activated protein kinase (MAPK) pathway through pretreatment with MAPK/Erk kinase 1 (MEK1) inhibitor PD98059, indicating that myostatin-stimulated activation of Erk1/2 negatively regulates myogenic differentiation. Activin receptor type IIb (ActRIIb) was previously suggested as the only type II membrane receptor triggering myostatin signaling. In this study, by using synthesized small interfering RNAs and dominant-negative ActRIIb, we show that myostatin failed to stimulate Erk1/2 phosphorylation and could not inhibit myoblast differentiation in ActRIIb-knockdown C2C12 cells, indicating that ActRIIb was required for myostatin-stimulated differentiation suppression. Altogether, our findings in this report provide the first evidence to reveal functional role of the Erk1/2 MAPK pathway in myostatin action as a negative regulator of muscle cell growth.
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Affiliation(s)
- Wei Yang
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, 5 Dong Dan San Tiao, Beijing 100-005, P.R. China
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Chilton L, Ohya S, Freed D, George E, Drobic V, Shibukawa Y, Maccannell KA, Imaizumi Y, Clark RB, Dixon IMC, Giles WR. K+ currents regulate the resting membrane potential, proliferation, and contractile responses in ventricular fibroblasts and myofibroblasts. Am J Physiol Heart Circ Physiol 2005; 288:H2931-9. [PMID: 15653752 DOI: 10.1152/ajpheart.01220.2004] [Citation(s) in RCA: 156] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Despite the important roles played by ventricular fibroblasts and myofibroblasts in the formation and maintenance of the extracellular matrix, neither the ionic basis for membrane potential nor the effect of modulating membrane potential on function has been analyzed in detail. In this study, whole cell patch-clamp experiments were done using ventricular fibroblasts and myofibroblasts. Time- and voltage-dependent outward K+ currents were recorded at depolarized potentials, and an inwardly rectifying K+ (Kir) current was recorded near the resting membrane potential (RMP) and at more hyperpolarized potentials. The apparent reversal potential of Kir currents shifted to more positive potentials as the external K+ concentration ([K+]o) was raised, and this Kir current was blocked by 100–300 μM Ba2+. RT-PCR measurements showed that mRNA for Kir2.1 was expressed. Accordingly, we conclude that Kir current is a primary determinant of RMP in both fibroblasts and myofibroblasts. Changes in [K+]o influenced fibroblast membrane potential as well as proliferation and contractile functions. Recordings made with a voltage-sensitive dye, DiBAC3(4), showed that 1.5 mM [K+]o resulted in a hyperpolarization, whereas 20 mM [K+]o produced a depolarization. Low [K+]o (1.5 mM) enhanced myofibroblast number relative to control (5.4 mM [K+]o). In contrast, 20 mM [K+]o resulted in a significant reduction in myofibroblast number. In separate assays, 20 mM [K+]o significantly enhanced contraction of collagen I gels seeded with myofibroblasts compared with control mechanical activity in 5.4 mM [K+]o. In combination, these results show that ventricular fibroblasts and myofibroblasts express a variety of K+ channel α-subunits and demonstrate that Kir current can modulate RMP and alter essential physiological functions.
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Affiliation(s)
- L Chilton
- Dept. of Bioengineering, Univ. of California-San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0412, USA
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