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Hou X, Ouyang J, Tang L, Wu P, Deng X, Yan Q, Shi L, Fan S, Fan C, Guo C, Liao Q, Li Y, Xiong W, Li G, Zeng Z, Wang F. KCNK1 promotes proliferation and metastasis of breast cancer cells by activating lactate dehydrogenase A (LDHA) and up-regulating H3K18 lactylation. PLoS Biol 2024; 22:e3002666. [PMID: 38905316 PMCID: PMC11192366 DOI: 10.1371/journal.pbio.3002666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Accepted: 05/07/2024] [Indexed: 06/23/2024] Open
Abstract
Breast cancer is the most prevalent malignancy and the most significant contributor to mortality in female oncology patients. Potassium Two Pore Domain Channel Subfamily K Member 1 (KCNK1) is differentially expressed in a variety of tumors, but the mechanism of its function in breast cancer is unknown. In this study, we found for the first time that KCNK1 was significantly up-regulated in human breast cancer and was correlated with poor prognosis in breast cancer patients. KCNK1 promoted breast cancer proliferation, invasion, and metastasis in vitro and vivo. Further studies unexpectedly revealed that KCNK1 increased the glycolysis and lactate production in breast cancer cells by binding to and activating lactate dehydrogenase A (LDHA), which promoted histones lysine lactylation to induce the expression of a series of downstream genes and LDHA itself. Notably, increased expression of LDHA served as a vicious positive feedback to reduce tumor cell stiffness and adhesion, which eventually resulted in the proliferation, invasion, and metastasis of breast cancer. In conclusion, our results suggest that KCNK1 may serve as a potential breast cancer biomarker, and deeper insight into the cancer-promoting mechanism of KCNK1 may uncover a novel therapeutic target for breast cancer treatment.
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Affiliation(s)
- Xiangchan Hou
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan, China
| | - Jiawei Ouyang
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan, China
| | - Le Tang
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan, China
| | - Pan Wu
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan, China
| | - Xiangying Deng
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan, China
| | - Qijia Yan
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Lei Shi
- Department of Pathology, the Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Songqing Fan
- Department of Pathology, the Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Chunmei Fan
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan, China
| | - Can Guo
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan, China
| | - Qianjin Liao
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China
| | - Yong Li
- Department of Medicine, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas, United States of America
| | - Wei Xiong
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan, China
| | - Guiyuan Li
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan, China
| | - Zhaoyang Zeng
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan, China
| | - Fuyan Wang
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan, China
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2
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Lin G, Lin L, Lin H, Chen W, Chen L, Chen X, Chen S, Lin Q, Xu Y, Zeng Y. KCNK3 inhibits proliferation and glucose metabolism of lung adenocarcinoma via activation of AMPK-TXNIP pathway. Cell Death Dis 2022; 8:360. [PMID: 35963847 PMCID: PMC9376064 DOI: 10.1038/s41420-022-01152-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 07/21/2022] [Accepted: 07/27/2022] [Indexed: 11/09/2022]
Abstract
Non-small cell lung cancer (NSCLC) is a primary histological subtype of lung cancer with increased morbidity and mortality. K+ channels have been revealed to be involved in carcinogenesis in various malignant tumors. However, TWIK-related acid-sensitive potassium channel 1 (TASK-1, also called KCNK3), a genetic member of K2P channels, remains an enigma in lung adenocarcinoma (LUAD). Herein, we investigated the pathological process of KCNK3 in proliferation and glucose metabolism of LUAD. The expressions of KCNK3 in LUAD tissues and corresponding adjacent tissues were identified by RNA sequencing, quantitative real-time polymerase chain reaction, western blot, and immunohistochemistry. Gain and loss-of-function assays were performed to estimate the role of KCNK3 in proliferation and glucose metabolism of LUAD. Additionally, energy metabolites of LUAD cells were identified by targeted metabolomics analysis. The expressions of metabolic molecules and active biomarkers associated with AMPK-TXNIP signaling pathway were detected via western blot and immunofluorescence. KCNK3 was significantly downregulated in LUAD tissues and correlated with patients' poor prognosis. Overexpression of KCNK3 largely regulated the process of oncogenesis and glycometabolism in LUAD in vitro and in vivo. Mechanistic studies found that KCNK3-mediated differential metabolites were mainly enriched in AMPK signaling pathway. Furthermore, rescue experiments demonstrated that KCNK3 suppressed proliferation and glucose metabolism via activation of the AMPK-TXNIP pathway in LUAD cells. In summary, our research highlighted an emerging role of KCNK3 in the proliferative activity and glycometabolism of LUAD, suggesting that KCNK3 may be an optimal predictor for prognosis and a potential therapeutic target of LUAD.
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Affiliation(s)
- Guofu Lin
- Department of Pulmonary and Critical Care Medicine, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian province, 362000, China.,Respiratory Medicine Center of Fujian Province, Quanzhou, Fujian province, 362000, China.,The Second Clinical College, Fujian Medical University, Quanzhou, Fujian province, 362000, China
| | - Lanlan Lin
- Department of Pulmonary and Critical Care Medicine, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian province, 362000, China.,Respiratory Medicine Center of Fujian Province, Quanzhou, Fujian province, 362000, China.,The Second Clinical College, Fujian Medical University, Quanzhou, Fujian province, 362000, China
| | - Hai Lin
- Department of Pulmonary and Critical Care Medicine, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian province, 362000, China.,Respiratory Medicine Center of Fujian Province, Quanzhou, Fujian province, 362000, China.,The Second Clinical College, Fujian Medical University, Quanzhou, Fujian province, 362000, China
| | - Wenhan Chen
- Department of Pulmonary and Critical Care Medicine, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian province, 362000, China.,Respiratory Medicine Center of Fujian Province, Quanzhou, Fujian province, 362000, China.,The Second Clinical College, Fujian Medical University, Quanzhou, Fujian province, 362000, China
| | - Luyang Chen
- Department of Pulmonary and Critical Care Medicine, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian province, 362000, China.,Respiratory Medicine Center of Fujian Province, Quanzhou, Fujian province, 362000, China.,The Second Clinical College, Fujian Medical University, Quanzhou, Fujian province, 362000, China
| | - Xiaohui Chen
- Department of Pulmonary and Critical Care Medicine, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian province, 362000, China.,Respiratory Medicine Center of Fujian Province, Quanzhou, Fujian province, 362000, China.,The Second Clinical College, Fujian Medical University, Quanzhou, Fujian province, 362000, China
| | - Shaohua Chen
- Department of Pathology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian province, 362000, China
| | - Qinhui Lin
- Department of Pulmonary and Critical Care Medicine, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian province, 362000, China.,Respiratory Medicine Center of Fujian Province, Quanzhou, Fujian province, 362000, China
| | - Yuan Xu
- Department of Pulmonary and Critical Care Medicine, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian province, 362000, China. .,Respiratory Medicine Center of Fujian Province, Quanzhou, Fujian province, 362000, China. .,Clinical Research Unit, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian province, 362000, China.
| | - Yiming Zeng
- Department of Pulmonary and Critical Care Medicine, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian province, 362000, China. .,Respiratory Medicine Center of Fujian Province, Quanzhou, Fujian province, 362000, China. .,Clinical Research Unit, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian province, 362000, China.
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3
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Krivoruchko AY, Yatsyk OA, Skokova AV, Kanibolotskaya AA. Genetic Markers of Karachaevsky Sheep Identified by Genome-Wide Association Study. RUSS J GENET+ 2022. [DOI: 10.1134/s1022795422020090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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4
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Selective regulation of human TRAAK channels by biologically active phospholipids. Nat Chem Biol 2020; 17:89-95. [PMID: 32989299 PMCID: PMC7746637 DOI: 10.1038/s41589-020-00659-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 08/21/2020] [Indexed: 11/22/2022]
Abstract
TRAAK is an ion channel from the two-pore domain potassium (K2P) channel family with roles in maintaining the resting membrane potential and fast action potential conduction. Regulated by a wide range of physical and chemical stimuli, the affinity and selectivity of K2P4.1 towards lipids remains poorly understood. Here we show the two isoforms of K2P4.1 have distinct binding preferences for lipids dependent on acyl chain length and position on the glycerol backbone. Unexpectedly, the channel can also discriminate the fatty acid linkage at the sn-1 position. Of the 33 lipids interrogated using native mass spectrometry, phosphatidic acid (PA) had the lowest equilibrium dissociation constants for both isoforms of K2P4.1. Liposome potassium flux assays with K2P4.1 reconstituted in defined lipid environments show that those containing PA activate the channel in a dose-dependent fashion. Our results begin to define the molecular requirements for the specific binding of lipids to K2P4.1.
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5
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Vyas VK, Parikh P, Ramani J, Ghate M. Medicinal Chemistry of Potassium Channel Modulators: An Update of Recent Progress (2011-2017). Curr Med Chem 2019; 26:2062-2084. [PMID: 29714134 DOI: 10.2174/0929867325666180430152023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 12/22/2017] [Accepted: 04/25/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND Potassium (K+) channels participate in many physiological processes, cardiac function, cell proliferation, neuronal signaling, muscle contractility, immune function, hormone secretion, osmotic pressure, changes in gene expression, and are involved in critical biological functions, and in a variety of diseases. Potassium channels represent a large family of tetrameric membrane proteins. Potassium channels activation reduces excitability, whereas channel inhibition increases excitability. OBJECTIVE Small molecule K+ channel activators and inhibitors interact with voltage-gated, inward rectifying, and two-pore tandem potassium channels. Due to their involvement in biological functions, and in a variety of diseases, small molecules as potassium channel modulators have received great scientific attention. METHODS In this review, we have compiled the literature, patents and patent applications (2011 to 2017) related to different chemical classes of potassium channel openers and blockers as therapeutic agents for the treatment of various diseases. Many different chemical classes of selective small molecule have emerged as potassium channel modulators over the past years. CONCLUSION This review discussed the current understanding of medicinal chemistry research in the field of potassium channel modulators to update the key advances in this field.
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Affiliation(s)
- Vivek K Vyas
- Department of Pharmaceutical Chemistry, Institute of Pharmacy, Nirma University, Ahmedabad 382 481 Gujarat, India
| | - Palak Parikh
- Department of Pharmaceutical Chemistry, Institute of Pharmacy, Nirma University, Ahmedabad 382 481 Gujarat, India
| | - Jonali Ramani
- Department of Pharmaceutical Chemistry, Institute of Pharmacy, Nirma University, Ahmedabad 382 481 Gujarat, India
| | - Manjunath Ghate
- Department of Pharmaceutical Chemistry, Institute of Pharmacy, Nirma University, Ahmedabad 382 481 Gujarat, India
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6
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Altered expression and functional role of ion channels in leukemia: bench to bedside. Clin Transl Oncol 2019; 22:283-293. [PMID: 31280433 DOI: 10.1007/s12094-019-02147-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 05/26/2019] [Indexed: 12/21/2022]
Abstract
Leukemic cells' (LCs) survival, proliferation, activation, differentiation, and invasiveness/migration can be mediated through the function of cation and anion channels that are involved in volume regulation, polarization, cytoskeleton, and extracellular matrix reorganization. This study will review the expression of ion channels in LCs and their possible function in leukemia progression. We searched relevant literature by a PubMed (2002-2019) of English-language literature using the terms "ion channels", "leukemia", "proliferation", "differentiation", "apoptosis", and "migration". Altered expression and dysfunction of ion channels can have a strong impact on hematopoietic cell and LCs physiology and signaling, which contributes to the vital processes such as proliferation, differentiation, and apoptosis. Indeed, it can be stated that changing expression of ion channels can affect the onset and progression as well as clinical features and therapeutic responses of leukemia via inducing the maintenance of LCs. Since ion channels are membrane proteins, they can be easily accessible in LCs for understanding their influence on leukemia progression. On the other hand, ion channels can be new potential targets for chemotherapeutic agents, which may open a novel clinical and pharmaceutical field in leukemia therapy.
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7
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Şterbuleac D. Molecular determinants of chemical modulation of two-pore domain potassium channels. Chem Biol Drug Des 2019; 94:1596-1614. [PMID: 31124599 DOI: 10.1111/cbdd.13571] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/29/2019] [Accepted: 05/05/2019] [Indexed: 12/16/2022]
Abstract
The K+ ion channels comprising the two-pore domain (K2P) family have specific biophysical roles in generating the critical regulatory K+ current. Ion flow through K2P channels and, implicitly, channel regulation is mediated by diverse metabolic and physical inputs such as mechanical stimulation, interaction with lipids or endogenous regulators, intra- or extracellular pH, and phosphorylation, while their function can be finely tuned by chemical compounds. In the latter category, some drug-channel interactions can lead to side effects or have clinical action, while identifying novel chemical modulators of K2Ps is an area of intense research. Due to their cellular and therapeutic importance, much attention was turned to these channels in recent years and several experimental approaches have pinpointed the molecular determinants of K2P chemical modulation. Given their unique structural features and properties, chemical modulators act on K2P channels in multiple and diverse ways. In this review, the particularities of K2P modulation by chemical compounds, such as binding modality, affinity, or position, are identified, synthesized, and linked to structural and functional properties in order to refer to how activators and blockers modify channel function and vice versa, focusing on specificity related to protein structure (and its modification) and cross-linking information among different subfamilies.
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Affiliation(s)
- Daniel Şterbuleac
- Doctoral School of Biology, Faculty of Biology, "Alexandru Ioan Cuza" University of Iasi, Iasi, Romania
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8
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Prionisti I, Bühler LH, Walker PR, Jolivet RB. Harnessing Microglia and Macrophages for the Treatment of Glioblastoma. Front Pharmacol 2019; 10:506. [PMID: 31231208 PMCID: PMC6560150 DOI: 10.3389/fphar.2019.00506] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 04/23/2019] [Indexed: 12/13/2022] Open
Abstract
Glioblastoma multiforme (GBM) is the most malignant form of brain tumors, with a dismal prognosis. During the course of the disease, microglia and macrophages both infiltrate the tumor microenvironment and contribute considerably in glioma development. Thus, tumor-associated microglia and macrophages have recently emerged as potentially key therapeutic targets. Here, we review the physiology of microglia and their responses in brain cancer. We further discuss current treatment options for GBM using radiotherapy, and novel advances in our knowledge of microglia physiology, with emphasis on the recently discovered pathway that controls the baseline motility of microglia processes. We argue that the latter pathway is an interesting therapeutic avenue to pursue for the treatment of glioblastoma.
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Affiliation(s)
- Ioanna Prionisti
- Division of Digestive and Transplantation Surgery, Geneva University Hospitals, Geneva, Switzerland
- Lemanic Neuroscience Doctoral School, Geneva, Switzerland
| | - Léo H. Bühler
- Division of Digestive and Transplantation Surgery, Geneva University Hospitals, Geneva, Switzerland
| | - Paul R. Walker
- Center for Translational Research in Onco-Hematology, Division of Oncology, Geneva University Hospitals – University of Geneva, Geneva, Switzerland
| | - Renaud B. Jolivet
- Département de Physique Nucléaire et Corpusculaire (DPNC), University of Geneva, Geneva, Switzerland
- European Organization for Nuclear Research (CERN), Geneva, Switzerland
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9
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Brennecke JT, de Groot BL. Mechanism of Mechanosensitive Gating of the TREK-2 Potassium Channel. Biophys J 2019; 114:1336-1343. [PMID: 29590591 DOI: 10.1016/j.bpj.2018.01.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 01/04/2018] [Accepted: 01/29/2018] [Indexed: 02/06/2023] Open
Abstract
The mechanism of mechanosensitive gating of ion channels underlies many physiological processes, including the sensations of touch, hearing, and pain perception. TREK-2 is the best-studied mechanosensitive member of the two-pore domain potassium channel family. Apart from pressure sensing, it responds to a diverse range of stimuli. Two states, termed "up" and "down," are known from x-ray structural crystallographic studies and have been suggested to differ in conductance. However, the structural details of the gating behavior are largely unknown. In this work, we used molecular dynamics simulations to study the conductance of the states as well as the effect of mechanical membrane stretch on the channel. We find that the down state is less conductive than the up state. The introduction of membrane stretch in the simulations shifts the state of the channel toward an up configuration, independent of the starting configuration, and also increases its conductance. The correlation of the selectivity filter state and the conductance supports a model in which the selectivity filter gates by a carbonyl flip. This gate is stabilized by the pore helices. We suggest a modulation of these helices by an interface to the transmembrane helices. Membrane pressure changes the conformation of the transmembrane helices directly and consequently also influences the channel conductance.
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Affiliation(s)
- Julian T Brennecke
- Department of Theoretical and Computational Biophysics, Computational Biomolecular Dynamics Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Bert L de Groot
- Department of Theoretical and Computational Biophysics, Computational Biomolecular Dynamics Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
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10
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Kawasaki K, Suzuki Y, Yamamura H, Imaizumi Y. Development of a Novel Cell-Based Assay System for High-Throughput Screening of Compounds Acting on Background Two-Pore Domain K + Channels. SLAS DISCOVERY 2019; 24:641-652. [PMID: 30802418 DOI: 10.1177/2472555219829745] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Two-pore domain K+ (K2P) channels are thought to be druggable targets. However, only a few agents specific for K2P channels have been identified, presumably due to the lack of an efficient screening system. To develop a new high-throughput screening (HTS) system targeting these channels, we have established a HEK293-based "test cell" expressing a mutated Na+ channel (Nav1.5) with markedly slowed inactivation, as well as a K+ channel (Kir2.1) that sets the membrane potential quite negative, close to K+ equilibrium potential. We found in this system that Kir2.1 block by 100 μM Ba2+ application consistently elicited a large depolarization like a long-lasting action potential. This maneuver resulted in cell death, presumably due to the sustained Na+ influx. When either the TWIK-related acid-sensitive K+ (TASK)-1 or TASK-3 channel was expressed in the test cells, Ba2+-induced cell death was markedly weakened. Stronger activation of TASK-1 by extracellular acidification further decreased the cell death. In contrast, the presence of K2P channel blockers enhanced cell death. IC50 values for TASK-1 and/or TASK-3 blockers acquired by measurements of relative cell viability were comparable to those obtained using patch-clamp recordings. Both blockers and openers of K2P channels can be accurately assessed with high efficiency and throughput by this novel HTS system.
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Affiliation(s)
- Keisuke Kawasaki
- 1 Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Yoshiaki Suzuki
- 1 Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Hisao Yamamura
- 1 Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Yuji Imaizumi
- 1 Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan.,2 Department of Research and Development, ChanneloSearch Technology Co., Ltd., Nagoya, Japan
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11
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Lamas JA, Fernández-Fernández D. Tandem pore TWIK-related potassium channels and neuroprotection. Neural Regen Res 2019; 14:1293-1308. [PMID: 30964046 PMCID: PMC6524494 DOI: 10.4103/1673-5374.253506] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
TWIK-related potassium channels (TREK) belong to a subfamily of the two-pore domain potassium channels family with three members, TREK1, TREK2 and TWIK-related arachidonic acid-activated potassium channels. The two-pore domain potassium channels is the last big family of channels being discovered, therefore it is not surprising that most of the information we know about TREK channels predominantly comes from the study of heterologously expressed channels. Notwithstanding, in this review we pay special attention to the limited amount of information available on native TREK-like channels and real neurons in relation to neuroprotection. Mainly we focus on the role of free fatty acids, lysophospholipids and other neuroprotective agents like riluzole in the modulation of TREK channels, emphasizing on how important this modulation may be for the development of new therapies against neuropathic pain, depression, schizophrenia, epilepsy, ischemia and cardiac complications.
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Affiliation(s)
- J Antonio Lamas
- Laboratory of Neuroscience, Biomedical Research Center (CINBIO), University of Vigo, Vigo, Galicia, Spain
| | - Diego Fernández-Fernández
- Laboratory of Neuroscience, Biomedical Research Center (CINBIO), University of Vigo, Vigo, Galicia, Spain
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12
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SUMOylation and calcium signalling: potential roles in the brain and beyond. Neuronal Signal 2017; 1:NS20160010. [PMID: 32714579 PMCID: PMC7373246 DOI: 10.1042/ns20160010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 07/10/2017] [Accepted: 07/11/2017] [Indexed: 12/23/2022] Open
Abstract
Small ubiquitin-like modifier (SUMO) conjugation (or SUMOylation) is a post-translational protein modification implicated in alterations to protein expression, localization and function. Despite a number of nuclear roles for SUMO being well characterized, this process has only started to be explored in relation to membrane proteins, such as ion channels. Calcium ion (Ca2+) signalling is crucial for the normal functioning of cells and is also involved in the pathophysiological mechanisms underlying relevant neurological and cardiovascular diseases. Intracellular Ca2+ levels are tightly regulated; at rest, most Ca2+ is retained in organelles, such as the sarcoplasmic reticulum, or in the extracellular space, whereas depolarization triggers a series of events leading to Ca2+ entry, followed by extrusion and reuptake. The mechanisms that maintain Ca2+ homoeostasis are candidates for modulation at the post-translational level. Here, we review the effects of protein SUMOylation, including Ca2+ channels, their proteome and other proteins associated with Ca2+ signalling, on vital cellular functions, such as neurotransmission within the central nervous system (CNS) and in additional systems, most prominently here, in the cardiac system.
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13
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Oakes V, Furini S, Pryde D, Domene C. Exploring the Dynamics of the TWIK-1 Channel. Biophys J 2017; 111:775-784. [PMID: 27558721 PMCID: PMC5002071 DOI: 10.1016/j.bpj.2016.07.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 05/13/2016] [Accepted: 07/11/2016] [Indexed: 01/02/2023] Open
Abstract
Potassium channels in the two-pore domain family (K2P) have various structural attributes that differ from those of other K(+) channels, including a dimeric assembly constituted of nonidentical domains and an expansive extracellular cap. Crystallization of the prototypical K2P channel, TWIK-1, finally revealed the structure of these characteristics in atomic detail, allowing computational studies to be undertaken. In this study, we performed molecular-dynamics simulations for a cumulative time of ∼1 μs to discern the mechanism of ion transport throughout TWIK-1. We observed the free passage of ions beneath the extracellular cap and identified multiple high-occupancy sites in close proximity to charged residues on the protein surface. Despite the overall topological similarity of the x-ray structure of the selectivity filter to other K(+) channels, the structure diverges significantly in molecular-dynamics simulations as a consequence of nonconserved residues in both pore domains contributing to the selectivity filter (T118 and L228). The behavior of such residues has been linked to channel inactivation and the phenomenon of dynamic selectivity, where TWIK-1 displays robust Na(+) inward flux in response to subphysiological K(+) concentrations.
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Affiliation(s)
- Victoria Oakes
- Department of Chemistry, King's College London, London, United Kingdom
| | - Simone Furini
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - David Pryde
- Worldwide Medicinal Chemistry, Pfizer Neuroscience and Pain Research Unit, Cambridge, United Kingdom
| | - Carmen Domene
- Department of Chemistry, King's College London, London, United Kingdom; Chemistry Research Laboratory, Mansfield Road, University of Oxford, Oxford, United Kingdom.
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14
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Schwingshackl A. The role of stretch-activated ion channels in acute respiratory distress syndrome: finally a new target? Am J Physiol Lung Cell Mol Physiol 2016; 311:L639-52. [PMID: 27521425 DOI: 10.1152/ajplung.00458.2015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 08/05/2016] [Indexed: 02/06/2023] Open
Abstract
Mechanical ventilation (MV) and oxygen therapy (hyperoxia; HO) comprise the cornerstones of life-saving interventions for patients with acute respiratory distress syndrome (ARDS). Unfortunately, the side effects of MV and HO include exacerbation of lung injury by barotrauma, volutrauma, and propagation of lung inflammation. Despite significant improvements in ventilator technologies and a heightened awareness of oxygen toxicity, besides low tidal volume ventilation few if any medical interventions have improved ARDS outcomes over the past two decades. We are lacking a comprehensive understanding of mechanotransduction processes in the healthy lung and know little about the interactions between simultaneously activated stretch-, HO-, and cytokine-induced signaling cascades in ARDS. Nevertheless, as we are unraveling these mechanisms we are gathering increasing evidence for the importance of stretch-activated ion channels (SACs) in the activation of lung-resident and inflammatory cells. In addition to the discovery of new SAC families in the lung, e.g., two-pore domain potassium channels, we are increasingly assigning mechanosensing properties to already known Na(+), Ca(2+), K(+), and Cl(-) channels. Better insights into the mechanotransduction mechanisms of SACs will improve our understanding of the pathways leading to ventilator-induced lung injury and lead to much needed novel therapeutic approaches against ARDS by specifically targeting SACs. This review 1) summarizes the reasons why the time has come to seriously consider SACs as new therapeutic targets against ARDS, 2) critically analyzes the physiological and experimental factors that currently limit our knowledge about SACs, and 3) outlines the most important questions future research studies need to address.
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15
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Abstract
Potassium ion (K(+)) channels play an important role in the modulation of calcium ion (Ca(2+)) signaling via control of the membrane potential. In T-lymphocytes, the voltage-gated K(+) channel, KV1.3, and the intermediate-conductance Ca(2+)-activated K(+) channel, KCa3.1, predominantly contribute to K(+) conductance, and are responsible for cell proliferation, differentiation, apoptosis and infiltration. Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, afflicts more than 0.1% of the population worldwide. In the chemically-induced IBD model mouse, an increase in KCa3.1 activity was observed in mesenteric lymph node CD4(+) T-lymphocytes, concomitant with an upregulation of KCa3.1 and a positive KCa3.1 regulator, NDPK-B. Pharmacological blockade of the KCa3.1 K(+) channel by TRAM-34 and/or ICA17043 elicited 1) a significant decrease in IBD severity, as assessed by diarrhea, visible fecal blood, inflammation and crypt damage of the colon; and 2) restoration of the expression levels of KCa3.1 and Th1 cytokines in CD4(+) T-lymphocytes in the IBD model. Recent studies have indicated the impact of K2P5.1 upregulation in T lymphocytes on the pathogenesis of autoimmune diseases such as rheumatoid arthritis and multiple sclerosis. The K2P5.1 K(+) channel is therefore highlighted as a potent therapeutic target in managing the pathogenesis of autoimmune diseases. Alternatively, pre-mRNA splicing of ion channels is associated with the development and progression of various diseases, including autoimmune diseases. Therefore, mRNA-splicing mechanisms underlying the transcriptional regulation of K2P5.1 K(+) channels may be a new strategic therapeutic target for autoimmune and inflammatory diseases.
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Affiliation(s)
- Susumu Ohya
- Department of Pharmacology, Kyoto Pharmaceutical University
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16
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Nakakura S, Matsui M, Sato A, Ishii M, Endo K, Muragishi S, Murase M, Kito H, Niguma H, Kurokawa N, Fujii M, Araki M, Araki K, Ohya S. Pathophysiological significance of the two-pore domain K(+) channel K2P5.1 in splenic CD4(+)CD25(-) T cell subset from a chemically-induced murine inflammatory bowel disease model. Front Physiol 2015; 6:299. [PMID: 26578971 PMCID: PMC4621418 DOI: 10.3389/fphys.2015.00299] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 10/09/2015] [Indexed: 01/17/2023] Open
Abstract
The alkaline pH-activated, two-pore domain K(+) channel K2P5.1 (also known as TASK2/KCNK5) plays an important role in maintaining the resting membrane potential, and contributes to the control of Ca(2+) signaling in several types of cells. Recent studies highlighted the potential role of the K2P5.1 K(+) channel in the pathogenesis of autoimmune diseases such as rheumatoid arthritis and multiple sclerosis. The aim of the present study was to elucidate the pathological significance of the K2P5.1 K(+) channel in inflammatory bowel disease (IBD). The degrees of colitis, colonic epithelial damage, and colonic inflammation were quantified in the dextran sulfate sodium-induced mouse IBD model by macroscopic and histological scoring systems. The expression and functional activity of K2P5.1 in splenic CD4(+) T cells were measured using real-time PCR, Western blot, and fluorescence imaging assays. A significant increase was observed in the expression of K2P5.1 in the splenic CD4(+) T cells of the IBD model. Concomitant with this increase, the hyperpolarization response induced by extracellular alkaline pH was significantly larger in the IBD model with the corresponding intracellular Ca(2+) rises. The expression of K2P5.1 was higher in CD4(+)CD25(-) T cells than in CD4(+)CD25(+) regulatory T cells. The knockout of K2P5.1 in mice significantly suppressed the disease responses implicated in the IBD model. Alternations in intracellular Ca(2+) signaling following the dysregulated expression of K2P5.1 were associated with the disease pathogenesis of IBD. The results of the present study suggest that the K2P5.1 K(+) channel in CD4(+)CD25(-) T cell subset is a potential therapeutic target and biomarker for IBD.
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Affiliation(s)
- Sawa Nakakura
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Miki Matsui
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Aya Sato
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Mizuki Ishii
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Kyoko Endo
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Sayaka Muragishi
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Miki Murase
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Hiroaki Kito
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Hiroki Niguma
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Natsumi Kurokawa
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Masanori Fujii
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
| | - Masatake Araki
- Institute of Resource Development and Analysis, Kumamoto University Kumamoto, Japan
| | - Kimi Araki
- Institute of Resource Development and Analysis, Kumamoto University Kumamoto, Japan
| | - Susumu Ohya
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University Kyoto, Japan
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17
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Endo K, Kurokawa N, Kito H, Nakakura S, Fujii M, Ohya S. Molecular identification of the dominant-negative, splicing isoform of the two-pore domain K(+) channel K(2P)5.1 in lymphoid cells and enhancement of its expression by splicing inhibition. Biochem Pharmacol 2015; 98:440-52. [PMID: 26475531 DOI: 10.1016/j.bcp.2015.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 10/01/2015] [Indexed: 12/20/2022]
Abstract
The two-pore domain background K(+) channel K2P5.1 is expected as a possible therapeutic target for autoimmune and inflammatory disorders and cancers because it plays an important role in maintaining the resting membrane potential and regulation of Ca(2+) signaling in T lymphocytes and cancer cells. However, the lack of selective K2P5.1 blockers has led to difficulties conducting experimental studies on this K(+) channel. We identified a novel splicing isoform of K2P5.1, K2P5.1B from the mammalian spleen, which lacked the N-terminus of full-length K2P5.1A. A co-immunoprecipitation assay using mice spleen lysates revealed an interaction between K2P5.1A and K2P5.1B in the cytoplasmic C-terminal domain. In a heterologous HEK293 expression system, K2P5.1B inhibited the trafficking of K2P5.1A to the plasma membrane. The alkaline pHe-induced hyperpolarizing response was significantly suppressed in K2P5.1B-transfected human leukemia K562 cells. Enhancement in cell proliferation by the overexpression of K2P5.1A in K562 was significantly prevented by the transfection of K2P5.1B. The spliceosome inhibitor pladienolide B significantly enhanced the relative expression of K2P5.1B in K562, resulting in decreases in the activity of K2P5.1A. K2P5.1B suppresses the function of the K2P5.1 K(+) channel in a dominant-negative manner, suggesting that the mRNA splicing mechanisms underlying the transcriptional regulation of K2P5.1B may be a new therapeutic strategy for autoimmune and inflammatory disorders and cancers.
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Affiliation(s)
- Kyoko Endo
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
| | - Natsumi Kurokawa
- 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.
| | - Sawa Nakakura
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
| | - Masanori Fujii
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
| | - Susumu Ohya
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
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18
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Renigunta V, Schlichthörl G, Daut J. Much more than a leak: structure and function of K₂p-channels. Pflugers Arch 2015; 467:867-94. [PMID: 25791628 DOI: 10.1007/s00424-015-1703-7] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 03/09/2015] [Indexed: 11/27/2022]
Abstract
Over the last decade, we have seen an enormous increase in the number of experimental studies on two-pore-domain potassium channels (K2P-channels). The collection of reviews and original articles compiled for this special issue of Pflügers Archiv aims to give an up-to-date summary of what is known about the physiology and pathophysiology of K2P-channels. This introductory overview briefly describes the structure of K2P-channels and their function in different organs. Its main aim is to provide some background information for the 19 reviews and original articles of this special issue of Pflügers Archiv. It is not intended to be a comprehensive review; instead, this introductory overview focuses on some unresolved questions and controversial issues, such as: Do K2P-channels display voltage-dependent gating? Do K2P-channels contribute to the generation of action potentials? What is the functional role of alternative translation initiation? Do K2P-channels have one or two or more gates? We come to the conclusion that we are just beginning to understand the extremely complex regulation of these fascinating channels, which are often inadequately described as 'leak channels'.
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Affiliation(s)
- Vijay Renigunta
- Institute of Physiology and Pathophysiology, Marburg University, 35037, Marburg, Germany
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19
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Placing ion channels into a signaling network of T cells: from maturing thymocytes to healthy T lymphocytes or leukemic T lymphoblasts. BIOMED RESEARCH INTERNATIONAL 2015; 2015:750203. [PMID: 25866806 PMCID: PMC4383400 DOI: 10.1155/2015/750203] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 09/19/2014] [Indexed: 12/20/2022]
Abstract
T leukemogenesis is a multistep process, where the genetic errors during T cell maturation cause the healthy progenitor to convert into the leukemic precursor that lost its ability to differentiate but possesses high potential for proliferation, self-renewal, and migration. A new misdirecting "leukemogenic" signaling network appears, composed by three types of participants which are encoded by (1) genes implicated in determined stages of T cell development but deregulated by translocations or mutations, (2) genes which normally do not participate in T cell development but are upregulated, and (3) nondifferentially expressed genes which become highly interconnected with genes expressed differentially. It appears that each of three groups may contain genes coding ion channels. In T cells, ion channels are implicated in regulation of cell cycle progression, differentiation, activation, migration, and cell death. In the present review we are going to reveal a relationship between different genetic defects, which drive the T cell neoplasias, with calcium signaling and ion channels. We suggest that changes in regulation of various ion channels in different types of the T leukemias may provide the intracellular ion microenvironment favorable to maintain self-renewal capacity, arrest differentiation, induce proliferation, and enhance motility.
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20
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Dong YY, Pike ACW, Mackenzie A, McClenaghan C, Aryal P, Dong L, Quigley A, Grieben M, Goubin S, Mukhopadhyay S, Ruda GF, Clausen MV, Cao L, Brennan PE, Burgess-Brown NA, Sansom MSP, Tucker SJ, Carpenter EP. K2P channel gating mechanisms revealed by structures of TREK-2 and a complex with Prozac. Science 2015; 347:1256-9. [PMID: 25766236 DOI: 10.1126/science.1261512] [Citation(s) in RCA: 212] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
TREK-2 (KCNK10/K2P10), a two-pore domain potassium (K2P) channel, is gated by multiple stimuli such as stretch, fatty acids, and pH and by several drugs. However, the mechanisms that control channel gating are unclear. Here we present crystal structures of the human TREK-2 channel (up to 3.4 angstrom resolution) in two conformations and in complex with norfluoxetine, the active metabolite of fluoxetine (Prozac) and a state-dependent blocker of TREK channels. Norfluoxetine binds within intramembrane fenestrations found in only one of these two conformations. Channel activation by arachidonic acid and mechanical stretch involves conversion between these states through movement of the pore-lining helices. These results provide an explanation for TREK channel mechanosensitivity, regulation by diverse stimuli, and possible off-target effects of the serotonin reuptake inhibitor Prozac.
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Affiliation(s)
- Yin Yao Dong
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK
| | - Ashley C W Pike
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK
| | - Alexandra Mackenzie
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK. Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Conor McClenaghan
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK. OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford OX1 3PN, UK
| | - Prafulla Aryal
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK. OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford OX1 3PN, UK. Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Liang Dong
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK
| | - Andrew Quigley
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK
| | - Mariana Grieben
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK
| | - Solenne Goubin
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK
| | | | - Gian Filippo Ruda
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK. Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK
| | - Michael V Clausen
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Lishuang Cao
- Pfizer Neusentis, Granta Park, Cambridge CB21 6GS, UK
| | - Paul E Brennan
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK. Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK
| | | | - Mark S P Sansom
- OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford OX1 3PN, UK. Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Stephen J Tucker
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK. OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford OX1 3PN, UK.
| | - Elisabeth P Carpenter
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK. OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford OX1 3PN, UK.
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21
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Feliciangeli S, Chatelain FC, Bichet D, Lesage F. The family of K2P channels: salient structural and functional properties. J Physiol 2015; 593:2587-603. [PMID: 25530075 DOI: 10.1113/jphysiol.2014.287268] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 12/10/2014] [Indexed: 12/11/2022] Open
Abstract
Potassium channels participate in many biological functions, from ion homeostasis to generation and modulation of the electrical membrane potential. They are involved in a large variety of diseases. In the human genome, 15 genes code for K(+) channels with two pore domains (K2P ). These channels form dimers of pore-forming subunits that produce background conductances finely regulated by a range of natural and chemical effectors, including signalling lipids, temperature, pressure, pH, antidepressants and volatile anaesthetics. Since the cloning of TWIK1, the prototypical member of this family, a lot of work has been carried out on their structure and biology. These studies are still in progress, but data gathered so far show that K2P channels are central players in many processes, including ion homeostasis, hormone secretion, cell development and excitability. A growing number of studies underline their implication in physiopathological mechanisms, such as vascular and pulmonary hypertension, cardiac arrhythmias, nociception, neuroprotection and depression. This review gives a synthetic view of the most noticeable features of these channels.
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Affiliation(s)
- Sylvain Feliciangeli
- LabEx ICST, Institut de Pharmacologie Moléculaire et Cellulaire, CNRS and Université de Nice-Sophia Antipolis, 660 Route des Lucioles, 06560, Valbonne, France
| | - Frank C Chatelain
- LabEx ICST, Institut de Pharmacologie Moléculaire et Cellulaire, CNRS and Université de Nice-Sophia Antipolis, 660 Route des Lucioles, 06560, Valbonne, France
| | - Delphine Bichet
- LabEx ICST, Institut de Pharmacologie Moléculaire et Cellulaire, CNRS and Université de Nice-Sophia Antipolis, 660 Route des Lucioles, 06560, Valbonne, France
| | - Florian Lesage
- LabEx ICST, Institut de Pharmacologie Moléculaire et Cellulaire, CNRS and Université de Nice-Sophia Antipolis, 660 Route des Lucioles, 06560, Valbonne, France
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22
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Bayliss DA, Barhanin J, Gestreau C, Guyenet PG. The role of pH-sensitive TASK channels in central respiratory chemoreception. Pflugers Arch 2014; 467:917-29. [PMID: 25346157 DOI: 10.1007/s00424-014-1633-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/08/2014] [Accepted: 10/12/2014] [Indexed: 01/16/2023]
Abstract
A number of the subunits within the family of K2P background K(+) channels are sensitive to changes in extracellular pH in the physiological range, making them likely candidates to mediate various pH-dependent processes. Based on expression patterns within several brainstem neuronal cell groups that are believed to function in CO2/H(+) regulation of breathing, three TASK subunits-TASK-1, TASK-2, and TASK-3-were specifically hypothesized to contribute to this central respiratory chemoreflex. For the acid-sensitive TASK-1 and TASK-3 channels, despite widespread expression at multiple levels within the brainstem respiratory control system (including presumptive chemoreceptor populations), experiments in knockout mice provided no evidence for their involvement in CO2 regulation of breathing. By contrast, the alkaline-activated TASK-2 channel has a more restricted brainstem distribution and was localized to the Phox2b-expressing chemoreceptor neurons of the retrotrapezoid nucleus (RTN). Remarkably, in a Phox2b(27Ala/+) mouse genetic model of congenital central hypoventilation syndrome (CCHS) that is characterized by reduced central respiratory chemosensitivity, selective ablation of Phox2b-expressing RTN neurons was accompanied by a corresponding loss of TASK-2 expression. Furthermore, genetic deletion of TASK-2 blunted RTN neuronal pH sensitivity in vitro, reduced alkaline-induced respiratory network inhibition in situ and diminished the ventilatory response to CO2/H(+) in vivo. Notably, a subpopulation of RTN neurons from TASK-2(-/-) mice retained their pH sensitivity, at least in part due to a residual pH-sensitive background K(+) current, suggesting that other mechanisms (and perhaps other K2P channels) for RTN neuronal pH sensitivity are yet to be identified.
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Affiliation(s)
- Douglas A Bayliss
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22908-0735, USA,
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23
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Aryal P, Abd-Wahab F, Bucci G, Sansom MSP, Tucker SJ. A hydrophobic barrier deep within the inner pore of the TWIK-1 K2P potassium channel. Nat Commun 2014; 5:4377. [PMID: 25001086 PMCID: PMC4102122 DOI: 10.1038/ncomms5377] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 06/11/2014] [Indexed: 12/27/2022] Open
Abstract
Recent X-ray crystal structures of the two-pore domain (K2P) family of potassium channels have revealed a unique structural architecture at the point where the cytoplasmic bundle-crossing gate is found in most other tetrameric K(+) channels. However, despite the apparently open nature of the inner pore in the TWIK-1 (K2P1/KCNK1) crystal structure, the reasons underlying its low levels of functional activity remain unclear. In this study, we use a combination of molecular dynamics simulations and functional validation to demonstrate that TWIK-1 possesses a hydrophobic barrier deep within the inner pore, and that stochastic dewetting of this hydrophobic constriction acts as a major barrier to ion conduction. These results not only provide an important insight into the mechanisms which control TWIK-1 channel activity, but also have important implications for our understanding of how ion permeation may be controlled in similar ion channels and pores.
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Affiliation(s)
- Prafulla Aryal
- 1] Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK [2] Department of Biochemistry, University of Oxford, Oxford OX1 3QX, UK [3] OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford OX1 3PT, UK
| | - Firdaus Abd-Wahab
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Giovanna Bucci
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Mark S P Sansom
- 1] Department of Biochemistry, University of Oxford, Oxford OX1 3QX, UK [2] OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford OX1 3PT, UK
| | - Stephen J Tucker
- 1] Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK [2] OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford OX1 3PT, UK
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24
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Potent and selective inhibitors of the TASK-1 potassium channel through chemical optimization of a bis-amide scaffold. Bioorg Med Chem Lett 2014; 24:3968-73. [PMID: 25017033 DOI: 10.1016/j.bmcl.2014.06.032] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 06/09/2014] [Accepted: 06/11/2014] [Indexed: 01/10/2023]
Abstract
TASK-1 is a two-pore domain potassium channel that is important to modulating cell excitability, most notably in the context of neuronal pathways. In order to leverage TASK-1 for therapeutic benefit, its physiological role needs better characterization; however, designing selective inhibitors that avoid the closely related TASK-3 channel has been challenging. In this study, a series of bis-amide derived compounds were found to demonstrate improved TASK-1 selectivity over TASK-3 compared to reported inhibitors. Optimization of a marginally selective hit led to analog 35 which displays a TASK-1 IC50=16 nM with 62-fold selectivity over TASK-3 in an orthogonal electrophysiology assay.
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25
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Tian C, Zhu R, Zhu L, Qiu T, Cao Z, Kang T. Potassium Channels: Structures, Diseases, and Modulators. Chem Biol Drug Des 2013; 83:1-26. [DOI: 10.1111/cbdd.12237] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Chuan Tian
- School of Life Sciences and Technology; Tongji University; Shanghai 200092 China
- School of Pharmacy; Liaoning University of Traditional Chinese Medicine; Dalian Liaoning 116600 China
| | - Ruixin Zhu
- School of Life Sciences and Technology; Tongji University; Shanghai 200092 China
| | - Lixin Zhu
- Department of Pediatrics; Digestive Diseases and Nutrition Center; The State University of New York at Buffalo; Buffalo NY 14226 USA
| | - Tianyi Qiu
- School of Life Sciences and Technology; Tongji University; Shanghai 200092 China
| | - Zhiwei Cao
- School of Life Sciences and Technology; Tongji University; Shanghai 200092 China
| | - Tingguo Kang
- School of Pharmacy; Liaoning University of Traditional Chinese Medicine; Dalian Liaoning 116600 China
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26
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Park KS, Han MH, Jang HK, Kim KA, Cha EJ, Kim WJ, Choi YH, Kim Y. The TREK2 Channel Is Involved in the Proliferation of 253J Cell, a Human Bladder Carcinoma Cell. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2013; 17:511-6. [PMID: 24381500 PMCID: PMC3874438 DOI: 10.4196/kjpp.2013.17.6.511] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 11/11/2013] [Accepted: 11/19/2013] [Indexed: 11/17/2022]
Abstract
Bladder cancer is the seventh most common cancer in men that smoke, and the incidence of disease increases with age. The mechanism of occurrence has not yet been established. Potassium channels have been linked with cell proliferation. Some two-pore domain K+ channels (K2P), such as TASK3 and TREK1, have recently been shown to be overexpressed in cancer cells. Here we focused on the relationship between cell growth and the mechanosensitive K2P channel, TREK2, in the human bladder cancer cell line, 253J. We confirmed that TREK2 was expressed in bladder cancer cell lines by Western blot and quantitative real-time PCR. Using the patch-clamp technique, the mechanosensitive TREK2 channel was recorded in the presence of symmetrical 150 mM KCl solutions. In 253J cells, the TREK2 channel was activated by polyunsaturated fatty acids, intracellular acidosis at -60 mV and mechanical stretch at -40 mV or 40 mV. Furthermore, small interfering RNA (siRNA)-mediated TREK2 knockdown resulted in a slight depolarization from -19.9 mV±0.8 (n=116) to -8.5 mV±1.4 (n=74) and decreased proliferation of 253J cells, compared to negative control siRNA. 253J cells treated with TREK2 siRNA showed a significant increase in the expression of cell cycle boundary proteins p21 and p53 and also a remarkable decrease in protein expression of cyclins D1 and D3. Taken together, the TREK2 channel is present in bladder cancer cell lines and may, at least in part, contribute to cell cycle-dependent growth.
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Affiliation(s)
- Kyung-Sun Park
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Min Ho Han
- Department of Biochemistry, Dongeui University College of Oriental Medicine, Busan 614-714, Korea. ; Personalized Tumor Engineering Research Center, College of Medicine, Chungbuk National University, Cheongju 361-763, Korea
| | - Hee Kyung Jang
- Department of Physiology, College of Medicine, Chungbuk National University, Cheongju 361-763, Korea. ; Personalized Tumor Engineering Research Center, College of Medicine, Chungbuk National University, Cheongju 361-763, Korea
| | - Kyung-A Kim
- Department of Biomedical Engineering, College of Medicine, Chungbuk National University, Cheongju 361-763, Korea. ; Personalized Tumor Engineering Research Center, College of Medicine, Chungbuk National University, Cheongju 361-763, Korea
| | - Eun-Jong Cha
- Department of Urology, College of Medicine, Chungbuk National University, Cheongju 361-763, Korea. ; Personalized Tumor Engineering Research Center, College of Medicine, Chungbuk National University, Cheongju 361-763, Korea
| | - Wun-Jae Kim
- Department of Urology, College of Medicine, Chungbuk National University, Cheongju 361-763, Korea. ; Personalized Tumor Engineering Research Center, College of Medicine, Chungbuk National University, Cheongju 361-763, Korea
| | - Yung Hyun Choi
- Department of Biochemistry, Dongeui University College of Oriental Medicine, Busan 614-714, Korea. ; Personalized Tumor Engineering Research Center, College of Medicine, Chungbuk National University, Cheongju 361-763, Korea
| | - Yangmi Kim
- Department of Physiology, College of Medicine, Chungbuk National University, Cheongju 361-763, Korea. ; Personalized Tumor Engineering Research Center, College of Medicine, Chungbuk National University, Cheongju 361-763, Korea
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27
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Bagriantsev SN, Ang KH, Gallardo-Godoy A, Clark KA, Arkin MR, Renslo AR, Minor DL. A high-throughput functional screen identifies small molecule regulators of temperature- and mechano-sensitive K2P channels. ACS Chem Biol 2013; 8:1841-51. [PMID: 23738709 PMCID: PMC3747594 DOI: 10.1021/cb400289x] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
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K2P (KCNK) potassium channels
generate “leak”
potassium currents that strongly influence cellular excitability and
contribute to pain, somatosensation, anesthesia, and mood. Despite
their physiological importance, K2Ps lack specific pharmacology.
Addressing this issue has been complicated by the challenges that
the leak nature of K2P currents poses for electrophysiology-based
high-throughput screening strategies. Here, we present a yeast-based
high-throughput screening assay that avoids this problem. Using a
simple growth-based functional readout, we screened a library of 106,281
small molecules and identified two new inhibitors and three new activators
of the mammalian K2P channel K2P2.1 (KCNK2, TREK-1). By combining biophysical, structure–activity,
and mechanistic analysis, we developed a dihydroacridine analogue,
ML67-33, that acts as a low micromolar, selective activator of temperature-
and mechano-sensitive K2P channels. Biophysical studies
show that ML67-33 reversibly increases channel currents by activating
the extracellular selectivity filter-based C-type gate that forms
the core gating apparatus on which a variety of diverse modulatory
inputs converge. The new K2P modulators presented here,
together with the yeast-based assay, should enable both mechanistic
and physiological studies of K2P activity and facilitate
the discovery and development of other K2P small molecule
modulators.
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Affiliation(s)
| | | | | | | | | | | | - Daniel L. Minor
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
94720, United States
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Minieri L, Pivonkova H, Caprini M, Harantova L, Anderova M, Ferroni S. The inhibitor of volume-regulated anion channels DCPIB activates TREK potassium channels in cultured astrocytes. Br J Pharmacol 2013; 168:1240-54. [PMID: 23072356 DOI: 10.1111/bph.12011] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 09/10/2012] [Accepted: 09/28/2012] [Indexed: 10/27/2022] Open
Abstract
BACKGROUND AND PURPOSE The ethacrynic acid derivative, 4-(2-butyl-6,7-dichlor-2-cyclopentylindan-1-on-5-yl) oxobutyric acid (DCPIB) is considered to be a specific and potent inhibitor of volume-regulated anion channels (VRACs). In the CNS, DCPIB was shown to be neuroprotective through mechanisms principally associated to its action on VRACs. We hypothesized that DCPIB could also regulate the activity of other astroglial channels involved in cell volume homeostasis. EXPERIMENTAL APPROACH Experiments were performed in rat cortical astrocytes in primary culture and in hippocampal astrocytes in situ. The effect of DCPIB was evaluated by patch-clamp electrophysiology and immunocytochemical techniques. Results were verified by comparative analysis with recombinant channels expressed in COS-7 cells. KEY RESULTS In cultured astrocytes, DCPIB promoted the activation of a K(+) conductance mediated by two-pore-domain K(+) (K(2P) ) channels. The DCPIB effect occluded that of arachidonic acid, which activates K(2P) channels K(2P) 2.1 (TREK-1) and K(2P) 10.1 (TREK-2) in cultured astrocytes. Immunocytochemical analysis suggests that cultured astrocytes express K(2P) 2.1 and K(2P) 10.1 proteins. Moreover, DCPIB opened recombinant K(2P) 2.1 and K(2P) 10.1 expressed in heterologous system. In brain slices, DCPIB did not augment the large background K(+) conductance in hippocampal astrocytes, but caused an increment in basal K(+) current of neurons. CONCLUSION AND IMPLICATIONS Our results indicate that the neuroprotective effect of DCPIB could be due, at least in part, to activation of TREK channels. DCPIB could be used as template to build new pharmacological tools able to increase background K(+) conductance in astroglia and neuronal cells.
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Affiliation(s)
- L Minieri
- Department of Human and General Physiology, University of Bologna, Bologna, Italy
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29
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Silveirinha V, Stephens GJ, Cimarosti H. Molecular targets underlying SUMO-mediated neuroprotection in brain ischemia. J Neurochem 2013; 127:580-91. [PMID: 23786482 DOI: 10.1111/jnc.12347] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 06/14/2013] [Accepted: 06/17/2013] [Indexed: 01/11/2023]
Abstract
SUMOylation (small ubiquitin-like modifier conjugation) is an important post-translational modification which is becoming increasingly implicated in the altered protein dynamics associated with brain ischemia. The function of SUMOylation in cells undergoing ischemic stress and the identity of small ubiquitin-like modifier (SUMO) targets remain in most cases unknown. However, the emerging consensus is that SUMOylation of certain proteins might be part of an endogenous neuroprotective response. This review brings together the current understanding of the underlying mechanisms and downstream effects of SUMOylation in brain ischemia, including processes such as autophagy, mitophagy and oxidative stress. We focus on recent advances and controversies regarding key central nervous system proteins, including those associated with the nucleus, cytoplasm and plasma membrane, such as glucose transporters (GLUT1, GLUT4), excitatory amino acid transporter 2 glutamate transporters, K+ channels (K2P1, Kv1.5, Kv2.1), GluK2 kainate receptors, mGluR8 glutamate receptors and CB1 cannabinoid receptors, which are reported to be SUMO-modified. A discussion of the roles of these molecular targets for SUMOylation could play following an ischemic event, particularly with respect to their potential neuroprotective impact in brain ischemia, is proposed.
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Affiliation(s)
- Vasco Silveirinha
- School of Pharmacy, Hopkins Building, University of Reading, Whiteknights, Reading, UK
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30
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Abstract
Dipeptidyl Peptidase-like Protein 6 (DPP6) is widely expressed in the brain where it co-assembles with Kv4 channels and KChIP auxiliary subunits to regulate the amplitude and functional properties of the somatodendritic A-current, ISA. Here we show that in cerebellar granule (CG) cells DPP6 also regulates resting membrane potential and input resistance by increasing the amplitude of the IK(SO) resting membrane current. Pharmacological analysis shows that DPP6 acts through the control of a channel with properties matching the K2P channel TASK-3. Heterologous expression and co-immunoprecipitation shows that DPP6 co-expression with TASK-3 results in the formation of a protein complex that enhances resting membrane potassium conductance. The co-regulation of resting and voltage-gated channels by DPP6 produces coordinate shifts in resting membrane potential and A-current gating that optimize the sensitivity of ISA inactivation gating to subthreshold fluctuations in resting membrane potential.
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31
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Saito K, Moore R, Negishi M. Nuclear receptor CAR specifically activates the two-pore K+ channel Kcnk1 gene in male mouse livers, which attenuates phenobarbital-induced hepatic hyperplasia. Toxicol Sci 2013; 132:151-61. [PMID: 23291559 DOI: 10.1093/toxsci/kfs338] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
KCNK1, a member of the family of two-pore K(+) ion channels, is specifically induced in the livers of male mice after phenobarbital treatment. Here, we have determined the molecular mechanism of this male-specific activation of the Kcnk1 gene and characterized KCNK1 as a phenobarbital-inducible antihyperplasia factor. Upon activation by phenobarbital, nuclear receptor CAR binds the 97-bp response element (-2441/-2345) within the Kcnk1 promoter. This binding is observed in the livers of male mice, but not in the livers of female mice and requires the pituitary gland, because hypophysectomy abrogates it. Hyperplasia further progressed in the livers of Kcnk1 ( -/- ) male mice compared with those of Kcnk1 ( +/+ ) males after phenobarbital treatment. Thus, KCNK1 suppresses phenobarbital-induced hyperplasia. These results indicate that phenobarbital treatment induces KCNK1 to elicit a male-specific and growth-suppressing signal. Thus, KCNK1 and Kcnk1 ( -/- ) mice provide an experimental tool for further investigation into the molecular mechanism of CAR-mediated promotion of the development of hepatocellular carcinoma in mice.
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Affiliation(s)
- Kosuke Saito
- National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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32
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Ion Channels. Mol Pharmacol 2012. [DOI: 10.1002/9781118451908.ch4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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33
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Mao J. Current challenges in translational pain research. Trends Pharmacol Sci 2012; 33:568-73. [PMID: 22959652 PMCID: PMC3482290 DOI: 10.1016/j.tips.2012.08.001] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Revised: 08/08/2012] [Accepted: 08/13/2012] [Indexed: 12/31/2022]
Abstract
The current gap between basic science research and the development of new analgesics presents a serious challenge for the future of pain medicine. This challenge is particularly difficult in the search for better treatment for comorbid chronic pain conditions because: (i) animal 'pain' models do not simulate multidimensional clinical pain conditions; (ii) animal behavioral testing does not assess subjective pain experience; (iii) preclinical data provide little assurance regarding the direction of new analgesic development; and (iv) clinical trials routinely use over-sanitized study populations and fail to capture the multidisciplinary consequences of comorbid chronic pain. Therefore, a paradigm shift in translational pain research is necessary to transform the current strategy from focusing on molecular switches of nociception to studying pain as a system-based integral response that includes psychosocial comorbidities. Several key issues of translational pain research are discussed in this review.
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Affiliation(s)
- Jianren Mao
- MGH Center for Translational Pain Research, Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
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34
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Functional analysis of missense variants in the TRESK (KCNK18) K channel. Sci Rep 2012; 2:237. [PMID: 22355750 PMCID: PMC3266952 DOI: 10.1038/srep00237] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 12/23/2011] [Indexed: 01/13/2023] Open
Abstract
A loss of function mutation in the TRESK K2P potassium channel (KCNK18), has recently been linked with typical familial migraine with aura. We now report the functional characterisation of additional TRESK channel missense variants identified in unrelated patients. Several variants either had no apparent functional effect, or they caused a reduction in channel activity. However, the C110R variant was found to cause a complete loss of TRESK function, yet is present in both sporadic migraine and control cohorts, and no variation in KCNK18 copy number was found. Thus despite the previously identified association between loss of TRESK channel activity and migraine in a large multigenerational pedigree, this finding indicates that a single non-functional TRESK variant is not alone sufficient to cause typical migraine and highlights the genetic complexity of this disorder.
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35
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Leak K⁺ channel mRNAs in dorsal root ganglia: relation to inflammation and spontaneous pain behaviour. Mol Cell Neurosci 2012; 49:375-86. [PMID: 22273507 PMCID: PMC3334831 DOI: 10.1016/j.mcn.2012.01.002] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 01/02/2012] [Accepted: 01/04/2012] [Indexed: 02/05/2023] Open
Abstract
Two pore domain potassium (K2P) channels (KCNKx.x) cause K + leak currents and are major contributors to resting membrane potential. Their roles in dorsal root ganglion (DRG) neurons normally, and in pathological pain models, are poorly understood. Therefore, we examined mRNA levels for 10 K2P channels in L4 and L5 rat DRGs normally, and 1 day and 4 days after unilateral cutaneous inflammation, induced by intradermal complete Freund's adjuvant (CFA) injections. Spontaneous foot lifting (SFL) duration (spontaneous pain behaviour) was measured in 1 day and 4 day rats < 1 h before DRG harvest. mRNA levels for KCNK channels and Kv1.4 relative to GAPDH (n = 4–6 rats/group) were determined with real-time RT-PCR. This study is the first to demonstrate expression of THIK1, THIK2 and TWIK2 mRNA in DRGs. Abundance in normal DRGs was, in descending order:
Kv1.4 > TRESK(KCNK18) > TRAAK(KCNK4) > TREK2(KCNK10) = TWIK2(KCNK6) > TREK1 (KCNK2) = THIK2(KCNK12) > TASK1(KCNK3) > TASK2(KCNK5) > THIK1(KCNK13) = TASK3(KCNK9).
During inflammation, the main differences from normal in DRG mRNA levels were bilateral, suggesting systemic regulation, although some channels showed evidence of ipsilateral modulation. By 1 day, bilateral K2P mRNA levels had decreased (THIK1) or increased (TASK1, THIK2) but by 4 days they were consistently decreased (TASK2, TASK3) or tended to decrease (excluding TRAAK). The decreased TASK2 mRNA was mirrored by decreased protein (TASK2-immunoreactivity) at 4 days. Ipsilateral mRNA levels at 4 days compared with 1 day were lower (TRESK, TASK1, TASK3, TASK2 and THIK2) or higher (THIK1). Ipsilateral SFL duration during inflammation was positively correlated with ipsilateral TASK1 and TASK3 mRNAs, and contralateral TASK1, TRESK and TASK2 mRNAs. Thus changes in K2P mRNA levels occurred during inflammation and for 4 K2P channels were associated with spontaneous pain behaviour (SFL). K2P channels and their altered expression are therefore associated with inflammation-induced pain.
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Ma XY, Yu JM, Zhang SZ, Liu XY, Wu BH, Wei XL, Yan JQ, Sun HL, Yan HT, Zheng JQ. External Ba2+ block of the two-pore domain potassium channel TREK-1 defines conformational transition in its selectivity filter. J Biol Chem 2011; 286:39813-22. [PMID: 21965685 DOI: 10.1074/jbc.m111.264788] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
TREK-1 is a member of the two-pore domain potassium channel family that is known as a leak channel and plays a key role in many physiological and pathological processes. The conformational transition of the selectivity filter is considered as an effective strategy for potassium channels to control the course of potassium efflux. It is well known that TREK-1 is regulated by a large volume of extracellular and intracellular signals. However, until now, little was known about the selectivity filter gating mechanism of the channel. In this research, it was found that Ba(2+) blocked the TREK-1 channel in a concentration- and time-dependent manner. A mutagenesis analysis showed that overlapped binding of Ba(2+) at the assumed K(+) binding site 4 (S4) within the selectivity filter was responsible for the inhibitory effects on TREK-1. Then, Ba(2+) was used as a probe to explore the conformational transition in the selectivity filter of the channel. It was confirmed that collapsed conformations were induced by extracellular K(+)-free and acidification at the selectivity filters, leading to nonconductive to permeable ions. Further detailed characterization demonstrated that the two conformations presented different properties. Additionally, the N-terminal truncated isoform (ΔN41), a product derived from alternative translation initiation, was identified as a constitutively nonconductive variant. Together, these results illustrate the important role of selectivity filter gating in the regulation of TREK-1 by the extracellular K(+) and proton.
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Affiliation(s)
- Xiao-Yun Ma
- Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China
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