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Sinha AS, Shibata S, Takamatsu Y, Akita T, Fukuda A, Mima T. Static Magnetic Field Stimulation Enhances Shunting Inhibition via a SLC26 Family Cl - Channel, Inducing Intrinsic Plasticity. J Neurosci 2024; 44:e1324222024. [PMID: 38302440 PMCID: PMC10904086 DOI: 10.1523/jneurosci.1324-22.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 01/09/2024] [Accepted: 01/13/2024] [Indexed: 02/03/2024] Open
Abstract
Magnetic fields are being used for detailed anatomical and functional examination of the human brain. In addition, evidence for their efficacy in treatment of brain dysfunctions is accumulating. Transcranial static magnetic field stimulation (tSMS) is a recently developed technique for noninvasively modifying brain functions. In tSMS, a strong and small magnet when placed over the skull can temporarily suppress brain functions. Its modulatory effects persist beyond the time of stimulation. However, the neurophysiological mechanisms underlying tSMS-induced plasticity remain unclear. Here, using acute motor cortical slice preparation obtained from male C57BL/6N mice, we show that tSMS alters the intrinsic electrical properties of neurons by altering the activity of chloride (Cl-) channels in neurons. Exposure of mouse pyramidal neurons to a static magnetic field (SMF) at a strength similar to human tSMS temporarily decreased their excitability and induced transient neuronal swelling. The effects of SMF were blocked by DIDS and GlyH-101, but not by NPPB, consistent with the pharmacological profile of SLC26A11, a transporter protein with Cl- channel activity. Whole-cell voltage-clamp recordings of the GlyH-101-sensitive Cl- current component showed significant enhancement of the component at both subthreshold and depolarized membrane potentials after SMF application, resulting in shunting inhibition and reduced repetitive action potential (AP) firing at the respective potentials. Thus, this study provides the first neurophysiological evidence for the inhibitory effect of tSMS on neuronal activity and advances our mechanistic understanding of noninvasive human neuromodulation.
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Affiliation(s)
- Adya Saran Sinha
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu-shi 431-3192, Shizuoka, Japan
| | - Sumiya Shibata
- Department of Physical Therapy, Niigata University of Health and Welfare, Niigata-shi 950-3198, Japan
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata-shi 950-3198, Japan
| | - Yasuyuki Takamatsu
- Department of Rehabilitation Science, Faculty of Health Sciences, Hokkaido University, Sapporo-shi 060-0812, Hokkaido, Japan
| | - Tenpei Akita
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu-shi 431-3192, Shizuoka, Japan
- Division of Health Science, Department of Basic Nursing, Hamamatsu University School of Medicine, Hamamatsu-shi 431-3192, Shizuoka, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu-shi 431-3192, Shizuoka, Japan
| | - Tatsuya Mima
- The Graduate School of Core Ethics and Frontier Sciences, Ritsumeikan University, Kyoto-shi 603-8577, Kyoto, Japan
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Niu L, Liu H, Li X, Wang L, Hua H, Cao Q, Xiang Q, Cai T, Zhu D. Design, synthesis, and biological evaluation of 2-(naphthalen-1-yloxy)-N-phenylacetamide derivatives as TRPM4 inhibitors for the treatment of prostate cancer. Bioorg Med Chem 2024; 98:117584. [PMID: 38168629 DOI: 10.1016/j.bmc.2023.117584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 12/11/2023] [Accepted: 12/26/2023] [Indexed: 01/05/2024]
Abstract
Transient receptor potential melastatin 4 (TRPM4) is considered to be a potential target for cancer and other human diseases. Herein, a series of 2-(naphthalen-1-yloxy)-N-phenylacetamide derivatives were designed and synthesized as new TRPM4 inhibitors, aiming to improve cellular potency. One of the most promising compounds, 7d (ZX08903), displayed promising antiproliferative activity against prostate cancer cell lines. 7d also suppressed colony formation and the expression of androgen receptor (AR) protein in prostate cancer cells. Furthermore, 7d can concentration-dependently induce cell apoptosis in prostate cancer cells. Collectively, these findings indicated that compound 7d may serve as a promising lead compound for further anticancer drug development.
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Affiliation(s)
- Le Niu
- Guoke Ningbo Life Science and Health Industry Research Institute, Ningbo No.2 Hospital, Ningbo, 315010, China; Department of Urology, the Second Affiliated Hospital of Nanjing Medical University, and Department of Medicinal Chemistry, School of Pharmacy, Nanjing Medical University, Nanjing, 211166, China
| | - Huina Liu
- Guoke Ningbo Life Science and Health Industry Research Institute, Ningbo No.2 Hospital, Ningbo, 315010, China
| | - Xiaomei Li
- Guoke Ningbo Life Science and Health Industry Research Institute, Ningbo No.2 Hospital, Ningbo, 315010, China
| | - Lin Wang
- Department of Urology, the Second Affiliated Hospital of Nanjing Medical University, and Department of Medicinal Chemistry, School of Pharmacy, Nanjing Medical University, Nanjing, 211166, China
| | - Hui Hua
- Guoke Ningbo Life Science and Health Industry Research Institute, Ningbo No.2 Hospital, Ningbo, 315010, China
| | - Qiaofeng Cao
- Department of Urology, the Second Affiliated Hospital of Nanjing Medical University, and Department of Medicinal Chemistry, School of Pharmacy, Nanjing Medical University, Nanjing, 211166, China
| | - Qiuping Xiang
- Guoke Ningbo Life Science and Health Industry Research Institute, Ningbo No.2 Hospital, Ningbo, 315010, China
| | - Ting Cai
- Guoke Ningbo Life Science and Health Industry Research Institute, Ningbo No.2 Hospital, Ningbo, 315010, China.
| | - Dongsheng Zhu
- Department of Urology, the Second Affiliated Hospital of Nanjing Medical University, and Department of Medicinal Chemistry, School of Pharmacy, Nanjing Medical University, Nanjing, 211166, China.
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Presence of TRPA1 Modifies CD4+/CD8+ T Lymphocyte Ratio and Activation. Pharmaceuticals (Basel) 2022; 15:ph15010057. [PMID: 35056114 PMCID: PMC8781558 DOI: 10.3390/ph15010057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 12/24/2021] [Accepted: 12/28/2021] [Indexed: 12/10/2022] Open
Abstract
Transient Receptor Potential Ankyrin 1 (TRPA1) has been reported to influence neuroinflammation and lymphocyte function. We analysed the immune phenotype and activation characteristics of TRPA1-deficient mice (knockout—KO) generated by targeted deletion of the pore-loop domain of the ion channel. We compared TRPA1 mRNA and protein expression in monocyte and lymphocyte subpopulations isolated from primary and secondary lymphatic organs of wild type (WT) and KO mice. qRT-PCR and flow cytometric studies indicated a higher level of TRPA1 in monocytes than in lymphocytes, but both were orders of magnitude lower than in sensory neurons. We found lower CD4+/CD8+ thymocyte ratios, diminished CD4/CD8 rates, and B cell numbers in the KO mice. Early activation marker CD69 was lower in CD4+ T cells of KO, while the level of CD8+/CD25+ cells was higher. In vitro TcR-mediated activation did not result in significant differences in CD69 level between WT and KO splenocytes, but lower cytokine (IL-1β, IL-6, TNF-α, IL-17A, IL-22, and RANTES) secretion was observed in KO splenocytes. Basal intracellular Ca2+ level and TcR-induced Ca2+ signal in T lymphocytes did not differ significantly, but interestingly, imiquimod-induced Ca2+ level in KO thymocytes was higher. Our results support the role of TRPA1 in the regulation of activation, cytokine production, and T and B lymphocytes composition in mice.
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Wang M, Sun Y, Li L, Wu P, Dkw O, Shi H. Calcium Channels: Noteworthy Regulators and Therapeutic Targets in Dermatological Diseases. Front Pharmacol 2021; 12:702264. [PMID: 34489697 PMCID: PMC8418299 DOI: 10.3389/fphar.2021.702264] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 08/02/2021] [Indexed: 02/05/2023] Open
Abstract
Dysfunctional skin barrier and impaired skin homeostasis may lead to or aggravate a series of dermatologic diseases. A large variety of biological events and bioactive molecules are involved in the process of skin wound healing and functional recovery. Calcium ions (Ca2+) released from intracellular stores as well as influx through plasma membrane are essential to skin function. Growing evidence suggests that calcium influx is mainly regulated by calcium-sensing receptors and channels, including voltage-gated, transient potential receptor, store-operated, and receptor-operated calcium channels, which not only maintain cellular Ca2+ homeostasis, but also participate in cell proliferation and skin cell homeostasis through Ca2+-sensitive proteins such as calmodulin (CaM). Furthermore, distinct types of Ca2+ channels not merely work separately, they may work concertedly to regulate cell function. In this review, we discussed different calcium-sensing receptors and channels, including voltage-gated, transient receptor potential, store-operated, and receptor-operated calcium channels, particularly focusing on their regulatory functions and inherent interactions as well as calcium channels-related reagents and drugs, which is expected to bridge basic research and clinical applications in dermatologic diseases.
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Affiliation(s)
- Min Wang
- Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, Institute of Stem Cell, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Yaoxiang Sun
- Department of Clinical Laboratory, The Affiliated Yixing Hospital of Jiangsu University, Yixing, China
| | - Linli Li
- Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, Institute of Stem Cell, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Peipei Wu
- Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, Institute of Stem Cell, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Ocansey Dkw
- Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, Institute of Stem Cell, School of Medicine, Jiangsu University, Zhenjiang, China.,Directorate of University Health Services, University of Cape Coast, Cape Coast, Ghana
| | - Hui Shi
- Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, Institute of Stem Cell, School of Medicine, Jiangsu University, Zhenjiang, China
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Huang YQ, Jin HF, Zhang H, Tang CS, Du JB. Interaction among Hydrogen Sulfide and Other Gasotransmitters in Mammalian Physiology and Pathophysiology. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1315:205-236. [PMID: 34302694 DOI: 10.1007/978-981-16-0991-6_9] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Hydrogen sulfide (H2S), nitric oxide (NO), carbon monoxide (CO), and sulfur dioxide (SO2) were previously considered as toxic gases, but now they are found to be members of mammalian gasotransmitters family. Both H2S and SO2 are endogenously produced in sulfur-containing amino acid metabolic pathway in vivo. The enzymes catalyzing the formation of H2S are mainly CBS, CSE, and 3-MST, and the key enzymes for SO2 production are AAT1 and AAT2. Endogenous NO is produced from L-arginine under catalysis of three isoforms of NOS (eNOS, iNOS, and nNOS). HO-mediated heme catabolism is the main source of endogenous CO. These four gasotransmitters play important physiological and pathophysiological roles in mammalian cardiovascular, nervous, gastrointestinal, respiratory, and immune systems. The similarity among these four gasotransmitters can be seen from the same and/or shared signals. With many studies on the biological effects of gasotransmitters on multiple systems, the interaction among H2S and other gasotransmitters has been gradually explored. H2S not only interacts with NO to form nitroxyl (HNO), but also regulates the HO/CO and AAT/SO2 pathways. Here, we review the biosynthesis and metabolism of the gasotransmitters in mammals, as well as the known complicated interactions among H2S and other gasotransmitters (NO, CO, and SO2) and their effects on various aspects of cardiovascular physiology and pathophysiology, such as vascular tension, angiogenesis, heart contractility, and cardiac protection.
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Affiliation(s)
- Ya-Qian Huang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Hong-Fang Jin
- Department of Pediatrics, Peking University First Hospital, Beijing, China.
| | - Heng Zhang
- Department of Endocrinology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Chao-Shu Tang
- Department of Physiology and Pathophysiology, Peking University Health Science Centre, Beijing, China
| | - Jun-Bao Du
- Department of Pediatrics, Peking University First Hospital, Beijing, China.
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More KN, Lee Y, Kim K, Suh Y, Son Y, Chang D. Effect of TRPV1 Antagonist SC0030, a Potent Painkiller, on RANKL‐mediated Osteoclast Differentiation Involved in Bone Resorption. B KOREAN CHEM SOC 2020. [DOI: 10.1002/bkcs.11992] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Kunal N. More
- College of Pharmacy and Research Institute of Life and Pharmaceutical SciencesSunchon National University Suncheon 57922 Republic of Korea
| | - Yong‐Jin Lee
- College of Pharmacy and Research Institute of Life and Pharmaceutical SciencesSunchon National University Suncheon 57922 Republic of Korea
| | - Kwang‐Jin Kim
- College of Pharmacy and Research Institute of Life and Pharmaceutical SciencesSunchon National University Suncheon 57922 Republic of Korea
| | - Young‐Ger Suh
- College of Pharmacy, CHA University Pochen‐si Gyenggi‐do 11160 Republic of Korea
| | - Young‐Jin Son
- College of Pharmacy and Research Institute of Life and Pharmaceutical SciencesSunchon National University Suncheon 57922 Republic of Korea
| | - Dong‐Jo Chang
- College of Pharmacy and Research Institute of Life and Pharmaceutical SciencesSunchon National University Suncheon 57922 Republic of Korea
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7
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Lv W, Wang X, Xu Q, Lu W. Mechanisms and Characteristics of Sulfonylureas and Glinides. Curr Top Med Chem 2020; 20:37-56. [PMID: 31884929 DOI: 10.2174/1568026620666191224141617] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 08/30/2019] [Accepted: 09/22/2019] [Indexed: 12/25/2022]
Abstract
BACKGROUND Type 2 diabetes mellitus is a complex progressive endocrine disease characterized by hyperglycemia and life-threatening complications. It is the most common disorder of pancreatic cell function that causes insulin deficiency. Sulfonylurea is a class of oral hypoglycemic drugs. Over the past half century, these drugs, together with the subsequent non-sulfonylureas (glinides), have been the main oral drugs for insulin secretion. OBJECTIVE Through in-depth study, the medical profession considers it as an important drug for improving blood sugar control. METHODS The mechanism, characteristics, efficacy and side effects of sulfonylureas and glinides were reviewed in detail. RESULTS Sulfonylureas and glinides not only stimulated the release of insulin from pancreatic cells, but also had many extrapanular hypoglycemic effect, such as reducing the clearance rate of insulin in liver, reducing the secretion of glucagon, and enhancing the sensitivity of peripheral tissues to insulin in type 2 diabetes mellitus. CONCLUSION Sulfonylureas and glinides are effective first-line drugs for the treatment of diabetes mellitus. Although they have the risk of hypoglycemia, weight gain and cardiovascular disease, their clinical practicability and safety can be guaranteed as long as they are reasonably used.
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Affiliation(s)
- Wei Lv
- School of Materials Science and Engineering, Shanghai University, Shanghai, China.,Shanghai Huayi Resins Co., Ltd., Shanghai, China
| | - Xianqing Wang
- Charles Institute of Dermatology, University College Dublin, Dublin D04 V1W8, Ireland
| | - Qian Xu
- Charles Institute of Dermatology, University College Dublin, Dublin D04 V1W8, Ireland
| | - Wencong Lu
- School of Materials Science and Engineering, Shanghai University, Shanghai, China
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8
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Kushner J, Ferrer X, Marx SO. Roles and Regulation of Voltage-gated Calcium Channels in Arrhythmias. J Innov Card Rhythm Manag 2019; 10:3874-3880. [PMID: 32494407 PMCID: PMC7252866 DOI: 10.19102/icrm.2019.101006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 03/04/2019] [Indexed: 12/25/2022] Open
Abstract
Calcium flowing through voltage-dependent calcium channels into cardiomyocytes mediates excitation–contraction coupling, controls action-potential duration and automaticity in nodal cells, and regulates gene expression. Proper surface targeting and basal and hormonal regulation of calcium channels are vital for normal cardiac physiology. In this review, we discuss the roles of voltage-gated calcium channels in the heart and the mechanisms by which these channels are regulated by physiological signaling pathways in health and disease.
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Affiliation(s)
- Jared Kushner
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Xavier Ferrer
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Steven O Marx
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
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Inoue M, Harada K, Matsui M, Matsuoka H. Differences among muscarinic agonists in M 1 receptor-mediated nonselective cation channel activation and TASK1 channel inhibition in adrenal medullary cells. Eur J Pharmacol 2019; 843:104-112. [PMID: 30452911 DOI: 10.1016/j.ejphar.2018.11.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 11/15/2018] [Accepted: 11/15/2018] [Indexed: 10/27/2022]
Abstract
Muscarinic receptor stimulation induces depolarizing inward currents and catecholamine secretion in adrenal medullary (AM) cells from various mammals. In guinea-pig AM cells muscarine and oxotremorine at concentrations ≤ 1 μM produce activation of nonselective cation channels with a similar potency and efficacy, whereas muscarine at higher concentrations produces not only nonselective cation channel activation, but also TASK1 channel inhibition. In rat AM cells, the muscarinic M1 receptor is involved in TASK1 channel inhibition in response to muscarinic agonists, and the efficacy of oxotremorine is half that of muscarine. These pharmacological findings might indicate that different muscarinic receptor subtypes are responsible for the regulation of nonselective cation and TASK1 channel activities. The present study aimed to determine the muscarinic receptor subtypes involved in nonselective cation channel activation in guinea-pig and mouse AM cells. The inward current evoked by 1 μM muscarine was completely suppressed by 100 μM quinine, whereas 30 μM muscarine-induced inward currents were comprised of quinine-sensitive and -insensitive components. The electrophysiological and pharmacological properties of the muscarine-induced currents indicated that the quinine-sensitive and insensitive components are due to nonselective cation channel activation and TASK1 channel inhibition, respectively. Muscarine at 30 μM failed to induce any current in AM cells treated with muscarinic toxin 7 or genetically deleted of the M1 receptor. The KD value of VU0255035 against the muscarinic receptor mediating nonselective cation channel activation was 17.5 nM. These results indicate that the M1 receptor mediates nonselective cation channel activation as well as TASK1 channel inhibition.
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Affiliation(s)
- Masumi Inoue
- Department of Cell and Systems Physiology, University of Occupational and Environmental Health School of Medicine, Kitakyushu 807-8555, Japan.
| | - Keita Harada
- Department of Cell and Systems Physiology, University of Occupational and Environmental Health School of Medicine, Kitakyushu 807-8555, Japan
| | | | - Hidetada Matsuoka
- Department of Cell and Systems Physiology, University of Occupational and Environmental Health School of Medicine, Kitakyushu 807-8555, Japan
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Liu J, Hu G, Gong Y, Yu Q, He B, Li W, He Z, Hao W, He Z, Liu Y. Silencing of TRPM8 inhibits aggressive tumor phenotypes and enhances gemcitabine sensitivity in pancreatic cancer. Pancreatology 2018; 18:935-944. [PMID: 30316690 DOI: 10.1016/j.pan.2018.08.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 07/04/2018] [Accepted: 08/21/2018] [Indexed: 12/11/2022]
Abstract
The transient receptor potential TRPM8 ion channel is required for cellular proliferation in pancreatic epithelia and adenocarcinoma. To elucidate the mechanism that mediates the function of TRPM8, we examined its role in the proliferation and invasion of pancreatic cancer (PC) cells. TRPM8 expression increased in both the PC tissues and cell lines; a high TRPM8 expression was correlated with poorer prognosis in patients with PC. In PC cell lines, PACN-1 and BxPC-3, Ca2+ influxes could be evoked by TRPM8; the sensitivity of PC cells to gemcitabine was increased, while the proliferation and invasion of PC cells were suppressed after RNA interference-mediated silencing of TRPM8. The mechanism of TRPM8 in gemcitabine-based chemotherapy was then investigated. The expression and activity of multidrug resistance-associated proteins, P-gp, MRP-2, LRP, was significantly reduced in response to TRPM8 silence. Moreover, TRPM8 knockdown significantly increased hENT1 protein levels and the ratio of Bax/Bcl-2 while decreased the protein levels of RRM1. Thus, TRPM8 is required for PC cell proliferation and invasion and was closely related to the gemcitabine sensitivity of PC. The modulation of TRPM8 expression may help improve treatment response of PC by combining with traditional chemotherapy.
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Affiliation(s)
- JieFeng Liu
- Department of General Surgery, The Fourth Hospital of Changsha, Hunan Normal University, Changsha, 410006, People's Republic of China
| | - GuoHuang Hu
- Department of General Surgery, The Fourth Hospital of Changsha, Hunan Normal University, Changsha, 410006, People's Republic of China
| | - YuJing Gong
- Department of General Surgery, The Fourth Hospital of Changsha, Hunan Normal University, Changsha, 410006, People's Republic of China
| | - QianLe Yu
- Department of General Surgery, The Fourth Hospital of Changsha, Hunan Normal University, Changsha, 410006, People's Republic of China
| | - Bin He
- Department of General Surgery, The Fourth Hospital of Changsha, Hunan Normal University, Changsha, 410006, People's Republic of China
| | - WangHao Li
- Department of General Surgery, The Fourth Hospital of Changsha, Hunan Normal University, Changsha, 410006, People's Republic of China
| | - ZhiGuo He
- Department of General Surgery, The Fourth Hospital of Changsha, Hunan Normal University, Changsha, 410006, People's Republic of China
| | - WenJie Hao
- Department of General Surgery, The Fourth Hospital of Changsha, Hunan Normal University, Changsha, 410006, People's Republic of China
| | - ZiChao He
- Department of General Surgery, The Fourth Hospital of Changsha, Hunan Normal University, Changsha, 410006, People's Republic of China
| | - YiPing Liu
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, 410078, People's Republic of China.
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11
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Lee SR, Nilius B, Han J. Gaseous Signaling Molecules in Cardiovascular Function: From Mechanisms to Clinical Translation. Rev Physiol Biochem Pharmacol 2018; 174:81-156. [PMID: 29372329 DOI: 10.1007/112_2017_7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Carbon monoxide (CO), hydrogen sulfide (H2S), and nitric oxide (NO) constitute endogenous gaseous molecules produced by specific enzymes. These gases are chemically simple, but exert multiple effects and act through shared molecular targets to control both physiology and pathophysiology in the cardiovascular system (CVS). The gases act via direct and/or indirect interactions with each other in proteins such as heme-containing enzymes, the mitochondrial respiratory complex, and ion channels, among others. Studies of the major impacts of CO, H2S, and NO on the CVS have revealed their involvement in controlling blood pressure and in reducing cardiac reperfusion injuries, although their functional roles are not limited to these conditions. In this review, the basic aspects of CO, H2S, and NO, including their production and effects on enzymes, mitochondrial respiration and biogenesis, and ion channels are briefly addressed to provide insight into their biology with respect to the CVS. Finally, potential therapeutic applications of CO, H2S, and NO with the CVS are addressed, based on the use of exogenous donors and different types of delivery systems.
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Affiliation(s)
- Sung Ryul Lee
- Department of Convergence Biomedical Science, Cardiovascular and Metabolic Disease Center, College of Medicine, Inje University, Busan, Republic of Korea
| | - Bernd Nilius
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Jin Han
- National Research Laboratory for Mitochondrial Signaling, Department of Physiology, Department of Health Sciences and Technology, BK21 Plus Project Team, Cardiovascular and Metabolic Disease Center, Inje University, Busan, Republic of Korea.
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12
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Animal toxins for channelopathy treatment. Neuropharmacology 2017; 132:83-97. [PMID: 29080794 DOI: 10.1016/j.neuropharm.2017.10.031] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 10/09/2017] [Accepted: 10/24/2017] [Indexed: 12/18/2022]
Abstract
Ion channels are transmembrane proteins that allow passive flow of ions inside and/or outside of cells or cell organelles. Except mutations lead to nonfunctional protein production or abolished receptor entrance on the membrane surface an altered channel may have two principal conditions that can be corrected. The channel may conduct fewer ions through (loss-of-function mutations) or too many ions (gain-of-function mutations) compared to a normal channel. Toxins from animal venoms are specialised molecules that are generally oriented toward interactions with ion channels. This is a result of long coevolution between predators and their prey. On the molecular level, toxins activate or inhibit ion channels, so they are ideal molecules for restoring conductance in mutated channels. Another aspect of this long coevolution is that a broad variety of toxins have been fine tuned to recognize the channels of different species, keeping many amino acids substitution among sequences. Many peptide ligands with high selectivity to specific receptor subtypes have been isolated from animal venoms, some of which are absolutely non-toxic to humans and mammalians. It is expected that molecules that are selective to each known receptor can be found in animal venoms, but the pool of toxins currently does not override all receptors described as being involved in channelopathies. Modern investigating methods have enhanced the search process for selective ligands. One prominent method is a site-directed mutagenesis of existing toxins to change the selectivity or/and affinity to the selected receptor, which has shown positive results. This article is part of the Special Issue entitled 'Channelopathies.'
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Solé-Magdalena A, Martínez-Alonso M, Coronado CA, Junquera LM, Cobo J, Vega JA. Molecular basis of dental sensitivity: The odontoblasts are multisensory cells and express multifunctional ion channels. Ann Anat 2017; 215:20-29. [PMID: 28954208 DOI: 10.1016/j.aanat.2017.09.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 08/22/2017] [Accepted: 09/10/2017] [Indexed: 12/26/2022]
Abstract
Odontoblasts are the dental pulp cells responsible for the formation of dentin. In addition, accumulating data strongly suggest that they can also function as sensory cells that mediate the early steps of mechanical, thermic, and chemical dental sensitivity. This assumption is based on the expression of different families of ion channels involved in various modalities of sensitivity and the release of putative neurotransmitters in response to odontoblast stimulation which are able to act on pulp sensory nerve fibers. This review updates the current knowledge on the expression of transient-potential receptor ion channels and acid-sensing ion channels in odontoblasts, nerve fibers innervating them and trigeminal sensory neurons, as well as in pulp cells. Moreover, the innervation of the odontoblasts and the interrelationship been odontoblasts and nerve fibers mediated by neurotransmitters was also revisited. These data might provide the basis for novel therapeutic approaches for the treatment of dentin sensibility and/or dental pain.
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Affiliation(s)
- A Solé-Magdalena
- Departamento de Morfología y Biología Celular Universidad de Oviedo, Spain
| | - M Martínez-Alonso
- Departamento de Morfología y Biología Celular Universidad de Oviedo, Spain
| | - C A Coronado
- Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Temuco, Chile
| | - L M Junquera
- Departamento de Especialidades Médico-Quirúrgicas, Universidad de Oviedo, Spain; Servicio de Cirugía Maxilofacial, Hospital Universitario Central de Asturias, Oviedo, Spain
| | - J Cobo
- Departamento de Especialidades Médico-Quirúrgicas, Universidad de Oviedo, Spain; Instituto Asturiano de Odontología, Oviedo, Spain
| | - J A Vega
- Departamento de Morfología y Biología Celular Universidad de Oviedo, Spain; Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Temuco, Chile.
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14
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L-type calcium channels in exocytosis and endocytosis of chromaffin cells. Pflugers Arch 2017; 470:53-60. [DOI: 10.1007/s00424-017-2064-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 08/22/2017] [Accepted: 08/23/2017] [Indexed: 11/25/2022]
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15
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Hoyer D. 5-HT Receptor Nomenclature: Naming Names, Does It Matter? A Tribute to Maurice Rapport. ACS Chem Neurosci 2017; 8:908-919. [PMID: 28269984 DOI: 10.1021/acschemneuro.7b00011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The naming of 5-HT receptors has been challenging, especially in the early days when the concept of multiple receptors for a single neurotransmitter was considered to be unrealistic at best. Yet pharmacological (rank orders of potency in functional or biochemical settings) and transductional evidence (second messengers, electrophysiology) clearly indicated the existence of receptor families and subfamilies. The genetic revolution, with the cloning and study of recombinantly expressed receptors, and eventually the cloning of the human and other genomes have made such reservations obsolete. Further, the advances in structural biology, with the possibility to study ligand receptor complexes as crystals and/or using solution NMR have largely confirmed the complexity of the 5-HT receptor system: species differences, existence of multiple receptor active and inactive states, splice variants, editing variants, complexes with multiple interacting proteins and transduction bias. This is a short personal history on how advances in biochemistry, molecular biology, biophysics, imaging and medicinal chemistry, some lateral thinking, and a decent amount of collaborative spirit within the 5-HT receptor nomenclature committee and the 5-HT community at large have helped to better define the pharmacology of the 5-HT receptor family.
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Affiliation(s)
- Daniel Hoyer
- Department of Pharmacology and Therapeutics,
School of Biomedical Sciences, Faculty of Medicine, Dentistry and
Health Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia
- The Florey Institute of Neuroscience
and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, Victoria 3052, Australia
- Department of Molecular Medicine, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, California 92037, United States
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16
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Knutsen HK, Alexander J, Barregård L, Bignami M, Brüschweiler B, Ceccatelli S, Cottrill B, Dinovi M, Edler L, Grasl-Kraupp B, Hogstrand C, Hoogenboom LR, Nebbia CS, Oswald IP, Rose M, Roudot AC, Schwerdtle T, Vleminckx C, Vollmer G, Wallace H, Arnich N, Benford D, Botana L, Viviani B, Arcella D, Binaglia M, Horvath Z, Steinkellner H, van Manen M, Petersen A. Risks for public health related to the presence of tetrodotoxin (TTX) and TTX analogues in marine bivalves and gastropods. EFSA J 2017; 15:e04752. [PMID: 32625458 PMCID: PMC7010203 DOI: 10.2903/j.efsa.2017.4752] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Tetrodotoxin (TTX) and its analogues are produced by marine bacteria and have been detected in marine bivalves and gastropods from European waters. The European Commission asked EFSA for a scientific opinion on the risks to public health related to the presence of TTX and TTX analogues in marine bivalves and gastropods. The Panel on Contaminants in the Food Chain reviewed the available literature but did not find support for the minimum lethal dose for humans of 2 mg, mentioned in various reviews. Some human case reports describe serious effects at a dose of 0.2 mg, corresponding to 4 μg/kg body weight (bw). However, the uncertainties on the actual exposure in the studies preclude their use for derivation of an acute reference dose (ARfD). Instead, a group ARfD of 0.25 μg/kg bw, applying to TTX and its analogues, was derived based on a TTX dose of 25 μg/kg bw at which no apathy was observed in an acute oral study with mice, applying a standard uncertainty factor of 100. Estimated relative potencies for analogues are lower than that of TTX but are associated with a high degree of uncertainty. Based on the occurrence data submitted to EFSA and reported consumption days only, average and P95 exposures of 0.00-0.09 and 0.00-0.03 μg/kg bw, respectively, were calculated. Using a large portion size of 400 g bivalves and P95 occurrence levels of TTX, with exception of oysters, the exposure was below the group ARfD in all consumer groups. A concentration below 44 μg TTX equivalents/kg shellfish meat, based on a large portion size of 400 g, was considered not to result in adverse effects in humans. Liquid chromatography with tandem mass spectroscopy (LC-MS/MS) methods are the most suitable for identification and quantification of TTX and its analogues, with LOQs between 1 and 25 μg/kg.
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17
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Role of plasma membrane-associated AKAPs for the regulation of cardiac IK1 current by protein kinase A. Naunyn Schmiedebergs Arch Pharmacol 2017; 390:493-503. [DOI: 10.1007/s00210-017-1344-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 01/12/2017] [Indexed: 12/20/2022]
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18
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Alotaibi M, Kahlat K, Nedjadi T, Djouhri L. Effects of ZD7288, a hyperpolarization-activated cyclic nucleotide-gated (HCN) channel blocker, on term-pregnant rat uterine contractility in vitro. Theriogenology 2017; 90:141-146. [DOI: 10.1016/j.theriogenology.2016.11.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Revised: 11/22/2016] [Accepted: 11/24/2016] [Indexed: 12/01/2022]
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19
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Fluorescent protein-scorpion toxin chimera is a convenient molecular tool for studies of potassium channels. Sci Rep 2016; 6:33314. [PMID: 27650866 PMCID: PMC5030662 DOI: 10.1038/srep33314] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 08/24/2016] [Indexed: 12/20/2022] Open
Abstract
Ion channels play a central role in a host of physiological and pathological processes and are the second largest target for existing drugs. There is an increasing need for reliable tools to detect and visualize particular ion channels, but existing solutions suffer from a number of limitations such as high price, poor specificity, and complicated protocols. As an alternative, we produced recombinant chimeric constructs (FP-Tx) consisting of fluorescent proteins (FP) fused with potassium channel toxins from scorpion venom (Tx). In particular, we used two FP, eGFP and TagRFP, and two Tx, OSK1 and AgTx2, to create eGFP-OSK1 and RFP-AgTx2. We show that these chimeras largely retain the high affinity of natural toxins and display selectivity to particular ion channel subtypes. FP-Tx are displaced by other potassium channel blockers and can be used as an imaging tool in ion channel ligand screening setups. We believe FP-Tx chimeras represent a new efficient molecular tool for neurobiology.
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20
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Chen GL, Lei M, Zhou LP, Zeng B, Zou F. Borneol Is a TRPM8 Agonist that Increases Ocular Surface Wetness. PLoS One 2016; 11:e0158868. [PMID: 27448228 PMCID: PMC4957794 DOI: 10.1371/journal.pone.0158868] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 05/17/2016] [Indexed: 12/12/2022] Open
Abstract
Borneol is a compound widely used in ophthalmic preparations in China. Little is known about its exact role in treating eye diseases. Here we report that transient receptor potential melastatin 8 (TRPM8) channel is a pharmacological target of borneol and mediates its therapeutic effect in the eyes. Ca2+ measurement and electrophysiological recordings revealed that borneol activated TRPM8 channel in a temperature- and dose-dependent manner, which was similar to but less effective than the action of menthol, an established TRPM8 agonist. Borneol significantly increased tear production in guinea pigs without evoking nociceptive responses at 25°C, but failed to induce tear secretion at 35°C. In contrast, menthol evoked tearing response at both 25 and 35°C. TRPM8 channel blockers N-(3-Aminopropyl)-2-[(3-methylphenyl)methoxy]-N-(2-thienylmethyl)benzamide hydrochloride (AMTB) and N-(4-tert-butylphenyl)-4-(3-chloropyridin-2-yl)piperazine-1-carboxamide (BCTC) abolished borneol- and menthol-induced tear secretion. Borneol at micromolar concentrations did not affect the viability of human corneal epithelial cells. We conclude that borneol can activate the cold-sensing TRPM8 channel and modestly increase ocular surface wetness, which suggests it is an active compound in ophthalmic preparations and particularly useful in treating dry eye syndrome.
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Affiliation(s)
- Gui-Lan Chen
- Ministry of Education Key Laboratory of Bio-resources and Eco-environment, College of Life Sciences, Sichuan University, Chengdu, China
- Key Laboratory of Medical Electrophysiology, Ministry of Education, and Institute of Cardiovascular Research, Sichuan Medical University, Luzhou, China
| | - Ming Lei
- Key Laboratory of Medical Electrophysiology, Ministry of Education, and Institute of Cardiovascular Research, Sichuan Medical University, Luzhou, China
| | - Lu-Ping Zhou
- Key Laboratory of Medical Electrophysiology, Ministry of Education, and Institute of Cardiovascular Research, Sichuan Medical University, Luzhou, China
| | - Bo Zeng
- Key Laboratory of Medical Electrophysiology, Ministry of Education, and Institute of Cardiovascular Research, Sichuan Medical University, Luzhou, China
- * E-mail: (BZ); (FZ)
| | - Fangdong Zou
- Ministry of Education Key Laboratory of Bio-resources and Eco-environment, College of Life Sciences, Sichuan University, Chengdu, China
- * E-mail: (BZ); (FZ)
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21
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Wu YT, Yen SL, Li CF, Chan TC, Chen TJ, Lee SW, He HL, Chang IW, Hsing CH, Shiue YL. Overexpression of Transient Receptor Protein Cation Channel Subfamily A Member 1, Confers an Independent Prognostic Indicator in Nasopharyngeal Carcinoma. J Cancer 2016; 7:1181-8. [PMID: 27390592 PMCID: PMC4934025 DOI: 10.7150/jca.15326] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 04/26/2016] [Indexed: 12/20/2022] Open
Abstract
Background: Detection of oncogenes provides chances to understand tumor development and progression. Transient receptor protein cation channel subfamily A, member 1 (TRPA1) transcript was significantly upregulated in nasopharyngeal carcinoma (NPC) with a stepwise upregulation from low- to high-stage NPCs from a preliminary data analysis in the Gene Expression Omnibus database. The TRPA1 gene is a member of the TRP channel family, encoding integral membrane proteins that functions as cation channels. Loss of calcium homeostasis takes place in cancer cells. Methods: Immunostaining of TRPA1 was analyzed on 124 biopsies from NPC patients retrospectively. The H-score method was used to evaluate the immunoexpression of TRPA1. The correlations between H-score of TRPA1 protein level and clinicopathological factors, as well as the significances of TRPA1 protein level for disease-specific, distal-metastasis-free and local recurrence-free survivals were assessed. Results: These patients were characterized to be no initial metastasis and medicated with the traditional procedure. The TRPA1 score was found to be associated with clinicopathological parameters and patient survivals. Along with the guideline of 7th edition of the American Joint Committee on Cancer, we found that TRPA1 upregulation (50%) was associated with advanced primary tumor (P = 0.009) and overall clinical stage (P = 0.019). In univariate log-rank testing, primary tumor, nodal status, stage and TRPA1 protein level significantly contributed to worse disease-specific survival, distal metastasis-free survival and local recurrence-free survival. In multivariate analysis, high TRPA1 protein level and tumor stage emerged as independent prognostic indicators for inferior disease-specific survival (P = 0.014; P = 0.003), distal metastasis-free survival (P = 0.004; P = 0.034) and recurrence-free survival (P = 0.017; P = 0.015). Conclusions: The upregulation of TRPA1 protein level is frequently correlated to unfavorable prognosticators and gives rise to cancer progression in NPC patients.
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Affiliation(s)
- You-Ting Wu
- 1. Departments of Pathology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan;; 2. Department of Pathology, Chang Gung Memorial Hospital, Chia-Yi, Taiwan
| | - Shao-Lun Yen
- 1. Departments of Pathology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Chien-Feng Li
- 3. Department of Pathology, Chi-Mei Medical Center, Tainan, Taiwan;; 4. National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan;; 5. Department of Biotechnology, Southern Taiwan University of Science and Technology, Tainan, Taiwan;; 6. Institute of Clinical Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Ti-Chun Chan
- 3. Department of Pathology, Chi-Mei Medical Center, Tainan, Taiwan
| | - Tzu-Ju Chen
- 3. Department of Pathology, Chi-Mei Medical Center, Tainan, Taiwan
| | - Sung-Wei Lee
- 7. Department of Radiation Oncology, Chi-Mei Medical Center, Liouying, Tainan, Taiwan
| | - Hong-Lin He
- 8. Department of Pathology, E-DA Hospital, I-Shou University, Kaohsiung, Taiwan;; 9. Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - I-Wei Chang
- 8. Department of Pathology, E-DA Hospital, I-Shou University, Kaohsiung, Taiwan
| | - Chung-Hsi Hsing
- 10. Department of Anesthesiology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Yow-Ling Shiue
- 9. Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan;; 11. Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan;; 12. Doctoral degree program in Marine Biotechnology, National Sun Yat-sen University, Kaohsiung, Taiwan
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22
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Abstract
Approximately 80 genes in the human genome code for pore-forming subunits of potassium (K(+)) channels. Rare variants (mutations) in K(+) channel-encoding genes may cause heritable arrhythmia syndromes. Not all rare variants in K(+) channel-encoding genes are necessarily disease-causing mutations. Common variants in K(+) channel-encoding genes are increasingly recognized as modifiers of phenotype in heritable arrhythmia syndromes and in the general population. Although difficult, distinguishing pathogenic variants from benign variants is of utmost importance to avoid false designations of genetic variants as disease-causing mutations.
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Affiliation(s)
- Ahmad S Amin
- Department of Clinical and Experimental Cardiology, Heart Centre, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Arthur A M Wilde
- Department of Clinical and Experimental Cardiology, Heart Centre, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands; King Abdulaziz University, Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, PO Box 80200, Jeddah 21589, Kingdom of Saudi Arabia.
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23
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McGovern AE, Robusto J, Rakoczy J, Simmons DG, Phipps S, Mazzone SB. The effect of hyperpolarization-activated cyclic nucleotide-gated ion channel inhibitors on the vagal control of guinea pig airway smooth muscle tone. Br J Pharmacol 2016; 171:3633-50. [PMID: 24762027 DOI: 10.1111/bph.12745] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 02/10/2014] [Accepted: 02/14/2014] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND PURPOSE Subtypes of the hyperpolarization-activated cyclic nucleotide-gated (HCN) family of cation channels are widely expressed on nerves and smooth muscle cells in many organ systems, where they serve to regulate membrane excitability. Here we have assessed whether HCN channel inhibitors alter the function of airway smooth muscle or the neurons that regulate airway smooth muscle tone. EXPERIMENTAL APPROACH The effects of the HCN channel inhibitors ZD7288, zatebradine and Cs(+) were assessed on agonist and nerve stimulation-evoked changes in guinea pig airway smooth muscle tone using tracheal strips in vitro, an innervated tracheal tube preparation ex vivo or in anaesthetized mechanically ventilated guinea pigs in vivo. HCN channel expression in airway nerves was assessed using immunohistochemistry, PCR and in situ hybridization. KEY RESULTS HCN channel inhibition did not alter airway smooth muscle reactivity in vitro to exogenously administered smooth muscle spasmogens, but significantly potentiated smooth muscle contraction evoked by the sensory nerve stimulant capsaicin and electrical field stimulation of parasympathetic cholinergic postganglionic neurons. Sensory nerve hyperresponsiveness was also evident in in vivo following HCN channel blockade. Cs(+) , but not ZD7288, potentiated preganglionic nerve-dependent airway contractions and over time induced autorhythmic preganglionic nerve activity, which was not mimicked by inhibitors of potassium channels. HCN channel expression was most evident in vagal sensory ganglia and airway nerve fibres. CONCLUSIONS AND IMPLICATIONS HCN channel inhibitors had a previously unrecognized effect on the neural regulation of airway smooth muscle tone, which may have implications for some patients receiving HCN channel inhibitors for therapeutic purposes.
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Affiliation(s)
- Alice E McGovern
- School of Biomedical Sciences, University of Queensland, St Lucia, Qld, Australia
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24
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Wu MM, Lou J, Song BL, Gong YF, Li YC, Yu CJ, Wang QS, Ma TX, Ma K, Hartzell HC, Duan DD, Zhao D, Zhang ZR. Hypoxia augments the calcium-activated chloride current carried by anoctamin-1 in cardiac vascular endothelial cells of neonatal mice. Br J Pharmacol 2016; 171:3680-92. [PMID: 24758567 PMCID: PMC4128065 DOI: 10.1111/bph.12730] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 04/01/2014] [Accepted: 04/06/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE The molecular identity of calcium-activated chloride channels (CaCCs) in vascular endothelial cells remains unknown. This study sought to identify whether anoctamin-1 (Ano1, also known as TMEM16A) functions as a CaCC and whether hypoxia alters the biophysical properties of Ano1 in mouse cardiac vascular endothelial cells (CVECs). EXPERIMENTAL APPROACH Western blot, quantitative real-time PCR, confocal imaging analysis and patch-clamp analysis combined with pharmacological approaches were used to determine whether Ano1 was expressed and functioned as CaCC in CVECs. KEY RESULTS Ano1 was expressed in CVECs. The biophysical properties of the current generated in the CVECs, including the Ca2+ and voltage dependence, outward rectification, anion selectivity and the pharmacological profile, are similar to those described for CaCCs. The density of ICl(Ca) detected in CVECs was significantly inhibited by T16Ainh-A01, an Ano1 inhibitor, and a pore-targeting, specific anti-Ano1 antibody, and was markedly decreased in Ano1 gene knockdown CVECs. The density of ICl(Ca) was significantly potentiated in CVECs exposed to hypoxia, and this hypoxia-induced increase in the density of ICl(Ca) was inhibited by T16Ainh-A01 or anti-Ano1 antibody. Hypoxia also increased the current density of ICl(Ca) in Ano1 gene knockdown CVECs. CONCLUSIONS AND IMPLICATIONS Ano1 formed CaCC in CVECs of neonatal mice. Hypoxia enhances Ano1-mediated ICl(Ca) density via increasing its expression, altering the ratio of its splicing variants, sensitivity to membrane voltage and to Ca2+. Ano1 may play a role in the pathophysiological processes during ischaemia in heart, and therefore, Ano1 might be a potential therapeutic target to prevent ischaemic damage.
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Affiliation(s)
- Ming-Ming Wu
- Departments of Clinical Pharmacy and Cardiology, Institute of Clinical Pharmacy, The 2nd Affiliated Hospital, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin Medical University, Harbin, China
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25
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Melis N, Tauc M, Cougnon M, Bendahhou S, Giuliano S, Rubera I, Duranton C. Revisiting CFTR inhibition: a comparative study of CFTRinh -172 and GlyH-101 inhibitors. Br J Pharmacol 2016; 171:3716-27. [PMID: 24758416 PMCID: PMC4128068 DOI: 10.1111/bph.12726] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 04/04/2014] [Accepted: 04/10/2014] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND AND PURPOSE For decades, inhibitors of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel have been used as tools to investigate the role and function of CFTR conductance in cystic fibrosis research. In the early 2000s, two new and potent inhibitors of CFTR, CFTRinh-172 and GlyH-101, were described and are now widely used to inhibit specifically CFTR. However, despite some evidence, the effects of both drugs on other types of Cl−-conductance have been overlooked. In this context, we explore the specificity and the cellular toxicity of both inhibitors in CFTR-expressing and non–CFTR-expressing cells. EXPERIMENTAL APPROACH Using patch-clamp technique, we tested the effects of CFTRinh-172 and GlyH-101 inhibitors on three distinct types of Cl− currents: the CFTR-like conductance, the volume-sensitive outwardly rectifying Cl− conductance (VSORC) and finally the Ca2+-dependent Cl− conductance (CaCC). We also explored the effect of both inhibitors on cell viability using live/dead and cell proliferation assays in two different cell lines. KEY RESULTS We confirmed that these two compounds were potent inhibitors of the CFTR-mediated Cl− conductance. However,GlyH-101 also inhibited the VSORC conductance and the CaCC at concentrations used to inhibit CFTR. The CFTRinh-172 did not affect the CaCC but did inhibit the VSORC, at concentrations higher than 5 µM. Neither inhibitor (20 µM; 24 h exposure) affected cell viability, but both were cytotoxic at higher concentrations. CONCLUSIONS AND IMPLICATIONS Both inhibitors affected Cl− conductances apart from CFTR. Our results provided insights into their use in mouse models.
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Affiliation(s)
- N Melis
- University of Nice-Sophia Antipolis, LP2M CNRS-UMR7370, Faculté de médecine, Nice, France
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Abstract
This review attempts to give a concise and up-to-date overview on the role of potassium channels in epilepsies. Their role can be defined from a genetic perspective, focusing on variants and de novo mutations identified in genetic studies or animal models with targeted, specific mutations in genes coding for a member of the large potassium channel family. In these genetic studies, a demonstrated functional link to hyperexcitability often remains elusive. However, their role can also be defined from a functional perspective, based on dynamic, aggravating, or adaptive transcriptional and posttranslational alterations. In these cases, it often remains elusive whether the alteration is causal or merely incidental. With ∼80 potassium channel types, of which ∼10% are known to be associated with epilepsies (in humans) or a seizure phenotype (in animals), if genetically mutated, a comprehensive review is a challenging endeavor. This goal may seem all the more ambitious once the data on posttranslational alterations, found both in human tissue from epilepsy patients and in chronic or acute animal models, are included. We therefore summarize the literature, and expand only on key findings, particularly regarding functional alterations found in patient brain tissue and chronic animal models.
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Affiliation(s)
- Rüdiger Köhling
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock 18057, Germany
| | - Jakob Wolfart
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock 18057, Germany
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27
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Rogawski MA, Löscher W, Rho JM. Mechanisms of Action of Antiseizure Drugs and the Ketogenic Diet. Cold Spring Harb Perspect Med 2016; 6:a022780. [PMID: 26801895 PMCID: PMC4852797 DOI: 10.1101/cshperspect.a022780] [Citation(s) in RCA: 173] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Antiseizure drugs (ASDs), also termed antiepileptic drugs, are the main form of symptomatic treatment for people with epilepsy, but not all patients become free of seizures. The ketogenic diet is one treatment option for drug-resistant patients. Both types of therapy exert their clinical effects through interactions with one or more of a diverse set of molecular targets in the brain. ASDs act by modulation of voltage-gated ion channels, including sodium, calcium, and potassium channels; by enhancement of γ-aminobutyric acid (GABA)-mediated inhibition through effects on GABAA receptors, the GABA transporter 1 (GAT1) GABA uptake transporter, or GABA transaminase; through interactions with elements of the synaptic release machinery, including synaptic vesicle 2A (SV2A) and α2δ; or by blockade of ionotropic glutamate receptors, including α-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA) receptors. The ketogenic diet leads to increases in circulating ketones, which may contribute to the efficacy in treating pharmacoresistant seizures. Production in the brain of inhibitory mediators, such as adenosine, or ion channel modulators, such as polyunsaturated fatty acids, may also play a role. Metabolic effects, including diversion from glycolysis, are a further postulated mechanism. For some ASDs and the ketogenic diet, effects on multiple targets may contribute to activity. Better understanding of the ketogenic diet will inform the development of improved drug therapies to treat refractory seizures.
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Affiliation(s)
- Michael A Rogawski
- Department of Neurology, University of California, Davis, Sacramento, California 95817
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany
| | - Jong M Rho
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada Department of Physiology and Pharmacology, University of Calgary, Alberta, Canada
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Cascio MG, Zamberletti E, Marini P, Parolaro D, Pertwee RG. The phytocannabinoid, Δ⁹-tetrahydrocannabivarin, can act through 5-HT₁A receptors to produce antipsychotic effects. Br J Pharmacol 2016; 172:1305-18. [PMID: 25363799 DOI: 10.1111/bph.13000] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 10/22/2014] [Accepted: 10/28/2014] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND AND PURPOSE This study aimed to address the questions of whether Δ(9)-tetrahydrocannabivarin (THCV) can (i) enhance activation of 5-HT1 A receptors in vitro and (ii) induce any apparent 5-HT₁A receptor-mediated antipsychotic effects in vivo. EXPERIMENTAL APPROACH In vitro studies investigated the effect of THCV on targeting by 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) of 5-HT₁A receptors in membranes obtained from rat brainstem or human 5-HT₁A CHO cells, using [(35)S]-GTPγS and 8-[(3)H]-OH-DPAT binding assays. In vivo studies investigated whether THCV induces signs of 5-HT₁A receptor-mediated antipsychotic effects in rats. KEY RESULTS THCV (i) potently, albeit partially, displaced 8-[(3) H]-OH-DPAT from specific binding sites in rat brainstem membranes; (ii) at 100 nM, significantly enhanced 8-OH-DPAT-induced activation of receptors in these membranes; (iii) produced concentration-related increases in 8-[(3)H]-OH-DPAT binding to specific sites in membranes of human 5-HT₁A receptor-transfected CHO cells; and (iv) at 100 nM, significantly enhanced 8-OH-DPAT-induced activation of these human 5-HT₁A receptors. In phencyclidine-treated rats, THCV, like clozapine (i) reduced stereotyped behaviour; (ii) decreased time spent immobile in the forced swim test; and (iii) normalized hyperlocomotor activity, social behaviour and cognitive performance. Some of these effects were counteracted by the 5-HT₁A receptor antagonist, WAY100635, or could be reproduced by the CB₁ antagonist, AM251. CONCLUSIONS AND IMPLICATIONS Our findings suggest that THCV can enhance 5-HT₁A receptor activation, and that some of its apparent antipsychotic effects may depend on this enhancement. We conclude that THCV has therapeutic potential for ameliorating some of the negative, cognitive and positive symptoms of schizophrenia.
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Affiliation(s)
- Maria Grazia Cascio
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
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29
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Hind WH, England TJ, O'Sullivan SE. Cannabidiol protects an in vitro model of the blood-brain barrier from oxygen-glucose deprivation via PPARγ and 5-HT1A receptors. Br J Pharmacol 2016; 173:815-25. [PMID: 26497782 DOI: 10.1111/bph.13368] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 10/08/2015] [Accepted: 10/13/2015] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND AND PURPOSE In vivo and in vitro studies have demonstrated a protective effect of cannabidiol (CBD) in reducing infarct size in stroke models and against epithelial barrier damage in numerous disease models. We aimed to investigate whether CBD also affects blood-brain barrier (BBB) permeability following ischaemia. EXPERIMENTAL APPROACH Human brain microvascular endothelial cell (HBMEC) and human astrocyte co-cultures modelled the BBB. Ischaemia was modelled by oxygen-glucose deprivation (OGD) and permeability was measured by transepithelial electrical resistance. KEY RESULTS CBD (10 μM) prevented the increase in permeability caused by 4 h OGD. CBD was most effective when administered before the OGD, but protective effects were observed up to 2 h into reperfusion. This protective effect was inhibited by a PPARγ antagonist and partly reduced by a 5-HT1A receptor antagonist, but was unaffected by antagonists of cannabinoid CB1 or CB2 receptors, TRPV1 channels or adenosine A2A receptors. CBD also reduced cell damage, as measured by LDH release and by markers of cellular adhesion, such as the adhesion molecule VCAM-1. In HBMEC monocultures, CBD decreased VCAM-1 and increased VEGF levels, effects which were inhibited by PPARγ antagonism. CONCLUSIONS AND IMPLICATIONS These data suggest that preventing permeability changes at the BBB could represent an as yet unrecognized mechanism of CBD-induced neuroprotection in ischaemic stroke, a mechanism mediated by activation of PPARγ and 5-HT1A receptors.
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Affiliation(s)
- William H Hind
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby, UK
| | - Timothy J England
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby, UK
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30
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Hofer MJ, Campbell IL. Immunoinflammatory diseases of the central nervous system - the tale of two cytokines. Br J Pharmacol 2016; 173:716-28. [PMID: 25917268 PMCID: PMC4742300 DOI: 10.1111/bph.13175] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 04/15/2015] [Accepted: 04/22/2015] [Indexed: 12/23/2022] Open
Abstract
Cytokines are potent mediators of cellular communication that have crucial roles in the regulation of innate and adaptive immunoinflammatory responses. Clear evidence has emerged in recent years that the dysregulated production of cytokines may in itself be causative in the pathogenesis of certain immunoinflammatory disorders. Here we review current evidence for the involvement of two different cytokines, IFN-α and IL-6, as principal mediators of specific immunoinflammatory disorders of the CNS. IFN-α belongs to the type I IFN family and is causally linked to the development of inflammatory encephalopathy exemplified by the genetic disorder, Aicardi-Goutières syndrome. IL-6 belongs to the gp130 family of cytokines and is causally linked to a number of immunoinflammatory disorders of the CNS including neuromyelitis optica, idiopathic transverse myelitis and genetically linked autoinflammatory neurological disease. In addition to clinical evidence, experimental studies, particularly in genetically engineered mouse models with astrocyte-targeted, CNS-restricted production of IFN-α or IL-6 replicate many of the cardinal neuropathological features of these human cytokine-linked immunoinflammatory neurological disorders giving crucial evidence for a direct causative role of these cytokines and providing further rationale for the therapeutic targeting of these cytokines in neurological diseases where indicated.
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Affiliation(s)
- M J Hofer
- School of Molecular Bioscience, University of Sydney, Sydney, Australia
| | - I L Campbell
- School of Molecular Bioscience, University of Sydney, Sydney, Australia
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31
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Ta CM, Adomaviciene A, Rorsman NJG, Garnett H, Tammaro P. Mechanism of allosteric activation of TMEM16A/ANO1 channels by a commonly used chloride channel blocker. Br J Pharmacol 2016; 173:511-28. [PMID: 26562072 PMCID: PMC4728427 DOI: 10.1111/bph.13381] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 09/15/2015] [Accepted: 10/29/2015] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND AND PURPOSE Calcium-activated chloride channels (CaCCs) play varied physiological roles and constitute potential therapeutic targets for conditions such as asthma and hypertension. TMEM16A encodes a CaCC. CaCC pharmacology is restricted to compounds with relatively low potency and poorly defined selectivity. Anthracene-9-carboxylic acid (A9C), an inhibitor of various chloride channel types, exhibits complex effects on native CaCCs and cloned TMEM16A channels providing both activation and inhibition. The mechanisms underlying these effects are not fully defined. EXPERIMENTAL APPROACH Patch-clamp electrophysiology in conjunction with concentration jump experiments was employed to define the mode of interaction of A9C with TMEM16A channels. KEY RESULTS In the presence of high intracellular Ca(2+) , A9C inhibited TMEM16A currents in a voltage-dependent manner by entering the channel from the outside. A9C activation, revealed in the presence of submaximal intracellular Ca(2+) concentrations, was also voltage-dependent. The electric distance of A9C inhibiting and activating binding site was ~0.6 in each case. Inhibition occurred according to an open-channel block mechanism. Activation was due to a dramatic leftward shift in the steady-state activation curve and slowed deactivation kinetics. Extracellular A9C competed with extracellular Cl(-) , suggesting that A9C binds deep in the channel's pore to exert both inhibiting and activating effects. CONCLUSIONS AND IMPLICATIONS A9C is an open TMEM16A channel blocker and gating modifier. These effects require A9C to bind to a region within the pore that is accessible from the extracellular side of the membrane. These data will aid the future drug design of compounds that selectively activate or inhibit TMEM16A channels.
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Affiliation(s)
- Chau M Ta
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Aiste Adomaviciene
- Department of Pharmacology, University of Oxford, Oxford, UK.,Faculty of Life Sciences, The University of Manchester, Manchester, UK
| | - Nils J G Rorsman
- Department of Pharmacology, University of Oxford, Oxford, UK.,OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford, UK
| | - Hannah Garnett
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Paolo Tammaro
- Department of Pharmacology, University of Oxford, Oxford, UK.,OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford, UK
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Ma MM, Lin CX, Liu CZ, Gao M, Sun L, Tang YB, Zhou JG, Wang GL, Guan YY. Threonine532 phosphorylation in ClC-3 channels is required for angiotensin II-induced Cl(-) current and migration in cultured vascular smooth muscle cells. Br J Pharmacol 2016; 173:529-44. [PMID: 26562480 DOI: 10.1111/bph.13385] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 10/11/2015] [Accepted: 10/25/2015] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE Angiotensin II (AngII) induces migration and growth of vascular smooth muscle cell (VSMC), which is responsible for vascular remodelling in some cardiovascular diseases. Ang II also activates a Cl(-) current, but the underlying mechanism is not clear. EXPERIMENTAL APPROACH The A10 cell line and primary cultures of VSMC from control, ClC-3 channel null mice and WT mice made hypertensive with AngII infusions were used. Techniques employed included whole-cell patch clamp, co-immunoprecipitation, site-specific mutagenesis and Western blotting, KEY RESULTS In VSMC, AngII induced Cl(-) currents was carried by the chloride ion channel ClC-3. This current was absent in VSMC from ClC-3 channel null mice. The AngII-induced Cl(-) current involved interactions between ClC-3 channels and Rho-kinase 2 (ROCK2), shown by N- or C-terminal truncation of ClC-3 protein, ROCK2 siRNA and co-immunoprecipitation assays. Phosphorylation of ClC-3 channels at Thr(532) by ROCK2 was critical for AngII-induced Cl(-) current and VSMC migration. The ClC-3 T532D mutant (mutation of Thr(532) to aspartate), mimicking phosphorylated ClC-3 protein, significantly potentiated AngII-induced Cl(-) current and VSMC migration, while ClC-3 T532A (mutation of Thr(532) to alanine) had the opposite effects. AngII-induced cell migration was markedly decreased in VSMC from ClC-3 channel null mice that was insensitive to Y27632, an inhibitor of ROCK2. In addition, AngII-induced cerebrovascular remodelling was decreased in ClC-3 null mice, possibly by the ROCK2 pathway. CONCLUSIONS AND IMPLICATIONS ClC-3 protein phosphorylation at Thr(532) by ROCK2 is required for AngII-induced Cl(-) current and VSMC migration that are involved in AngII-induced vascular remodelling in hypertension.
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Affiliation(s)
- Ming-Ming Ma
- Department of Pharmacology, Cardiac and Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Cai-Xia Lin
- Department of Pharmacology, Cardiac and Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Can-Zhao Liu
- Department of Pharmacology, Cardiac and Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Min Gao
- Department of Pharmacology, Cardiac and Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Lu Sun
- Department of Pharmacology, Cardiac and Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Yong-Bo Tang
- Department of Pharmacology, Cardiac and Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Jia-Guo Zhou
- Department of Pharmacology, Cardiac and Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Guan-Lei Wang
- Department of Pharmacology, Cardiac and Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Yong-Yuan Guan
- Department of Pharmacology, Cardiac and Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
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Champeroux P, Le Guennec JY, Jude S, Laigot C, Maurin A, Sola ML, Fowler JSL, Richard S, Thireau J. The high frequency relationship: implications for torsadogenic hERG blockers. Br J Pharmacol 2016; 173:601-12. [PMID: 26589499 DOI: 10.1111/bph.13391] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 11/11/2015] [Accepted: 11/17/2015] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Ventricular arrhythmias induced by human ether-a-go-go related gene (hERG; Kv 11.1 channel) blockers are a consequence of alterations in ventricular repolarisation in association with high-frequency (HF) oscillations, which act as a primary trigger; the autonomic nervous system plays a modulatory role. In the present study, we investigated the role of β1 -adrenoceptors in the HF relationship between magnitude of heart rate and QT interval changes within discrete 10 s intervals (sorted into 5 bpm heart rate increments) and its implications for torsadogenic hERG blockers. EXPERIMENTAL APPROACH The HF relationship was studied under conditions of autonomic blockade with atenolol (β1 -adrenoceptor blocker) in the absence or presence of five hERG blockers in beagle dogs. In total, the effects of 14 hERG blockers on the HF relationship were investigated. KEY RESULTS All the torsadogenic hERG blockers tested caused a vertical shift in the HF relationship, while hERG blockers associated with a low risk of Torsades de Pointes did not cause any vertical shift. Atenolol completely prevented the effects four torsadogenic agents (quinidine, thioridazine, risperidone and terfenadine) on the HF relationship, but only partially reduced those of dofetilide, leading to the characterization of two types of torsadogenic agent. CONCLUSIONS AND IMPLICATIONS Analysis of the vertical shift in the HF relationship demonstrated that signs of transient sympathetic activation during HF oscillations in the presence of torsadogenic hERG blockers are mediated by β1 -adrenoceptors. We suggest the HF relationship as a new biomarker for assessing Torsades de pointes liability, with potential implications in both preclinical studies and the clinic.
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Affiliation(s)
- P Champeroux
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - J Y Le Guennec
- Laboratoire PHYMEDEXP, Physiologie et Médecine Expérimentale, Cœur et Muscles, INSERM U1046, CNRS UMR 9214, Université de Montpellier, CHU Arnaud de Villeneuve, 371 Avenue du doyen G. Giraud, 34295, Montpellier cedex 05, France
| | - S Jude
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - C Laigot
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - A Maurin
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - M L Sola
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - J S L Fowler
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - S Richard
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - J Thireau
- Laboratoire PHYMEDEXP, Physiologie et Médecine Expérimentale, Cœur et Muscles, INSERM U1046, CNRS UMR 9214, Université de Montpellier, CHU Arnaud de Villeneuve, 371 Avenue du doyen G. Giraud, 34295, Montpellier cedex 05, France
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Matthes E, Goepp J, Carlile GW, Luo Y, Dejgaard K, Billet A, Robert R, Thomas DY, Hanrahan JW. Low free drug concentration prevents inhibition of F508del CFTR functional expression by the potentiator VX-770 (ivacaftor). Br J Pharmacol 2016; 173:459-70. [PMID: 26492939 DOI: 10.1111/bph.13365] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 07/22/2015] [Accepted: 10/12/2015] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND AND PURPOSE The most common cystic fibrosis (CF) mutation F508del inhibits the gating and surface expression of CFTR, a plasma membrane anion channel. Optimal pharmacotherapies will probably require both a 'potentiator' to increase channel open probability and a 'corrector' that improves folding and trafficking of the mutant protein and its stability at the cell surface. Interaction between CF drugs has been reported but remains poorly understood. EXPERIMENTAL APPROACH CF bronchial epithelial cells were exposed to the corrector VX-809 (lumacaftor) and potentiator VX-770 (ivacaftor) individually or in combination. Functional expression of CFTR was assayed as the forskolin-stimulated short-circuit current (Isc ) across airway epithelial monolayers expressing F508del CFTR. KEY RESULTS The potentiated Isc response during forskolin stimulation was increased sixfold after pretreatment with VX-809 alone and reached ~11% that measured across non-CF monolayers. VX-770 (100 nM) and genistein (50 μM) caused similar levels of potentiation, which were not additive and were abolished by the CFTR inhibitor CFTRinh -172. The unbound fraction of VX-770 in plasma was 0.13 ± 0.04%, which together with previous measurements in patients given 250 mg p.o. twice daily, suggests a peak free plasma concentration of 1.5-8.5 nM. Chronic exposure to high VX-770 concentrations (>1 μM) inhibited functional correction by VX-809 but not in the presence of physiological protein levels (20-40 mg·mL(-1) ). Chronic exposure to a low concentration of VX-770 (100 nM) together with VX-809 (1 μM) also did not reduce the forskolin-stimulated Isc , relative to cells chronically exposed to VX-809 alone, provided it was assayed acutely using the same, clinically relevant concentration of potentiator. CONCLUSIONS AND IMPLICATIONS Chronic exposure to clinically relevant concentrations of VX-770 did not reduce F508del CFTR function. Therapeutic benefit of VX-770 + VX-809 (Orkambi) is probably limited by the efficacy of VX-809 rather than by inhibition by VX-770.
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Affiliation(s)
- Elizabeth Matthes
- Department of Physiology, McGill University, Montréal, QC, Canada.,CF Translational Research Centre, McGill University, Montréal, QC, Canada
| | - Julie Goepp
- Department of Physiology, McGill University, Montréal, QC, Canada.,CF Translational Research Centre, McGill University, Montréal, QC, Canada
| | - Graeme W Carlile
- CF Translational Research Centre, McGill University, Montréal, QC, Canada.,Department of Biochemistry, McGill University, Montréal, QC, Canada
| | - Yishan Luo
- Department of Physiology, McGill University, Montréal, QC, Canada.,CF Translational Research Centre, McGill University, Montréal, QC, Canada
| | - Kurt Dejgaard
- Department of Biochemistry, McGill University, Montréal, QC, Canada
| | - Arnaud Billet
- Department of Physiology, McGill University, Montréal, QC, Canada.,CF Translational Research Centre, McGill University, Montréal, QC, Canada
| | - Renaud Robert
- Department of Physiology, McGill University, Montréal, QC, Canada.,CF Translational Research Centre, McGill University, Montréal, QC, Canada
| | - David Y Thomas
- CF Translational Research Centre, McGill University, Montréal, QC, Canada.,Department of Biochemistry, McGill University, Montréal, QC, Canada
| | - John W Hanrahan
- Department of Physiology, McGill University, Montréal, QC, Canada.,CF Translational Research Centre, McGill University, Montréal, QC, Canada.,Research Institute of the McGill University Health Centre, Montréal, QC, Canada
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35
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Naylor J, Minard A, Gaunt HJ, Amer MS, Wilson LA, Migliore M, Cheung SY, Rubaiy HN, Blythe NM, Musialowski KE, Ludlow MJ, Evans WD, Green BL, Yang H, You Y, Li J, Fishwick CWG, Muraki K, Beech DJ, Bon RS. Natural and synthetic flavonoid modulation of TRPC5 channels. Br J Pharmacol 2016; 173:562-74. [PMID: 26565375 PMCID: PMC4728423 DOI: 10.1111/bph.13387] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 10/14/2015] [Accepted: 10/20/2015] [Indexed: 11/28/2022] Open
Abstract
Background and Purpose The TRPC5 proteins assemble to create calcium‐permeable, non‐selective, cationic channels. We sought novel modulators of these channels through studies of natural products. Experimental Approach Intracellular calcium measurements and patch clamp recordings were made from cell lines. Compounds were generated by synthetic chemistry. Key Results Through a screen of natural products used in traditional Chinese medicines, the flavonol galangin was identified as an inhibitor of lanthanide‐evoked calcium entry in TRPC5 overexpressing HEK 293 cells (IC50 0.45 μM). Galangin also inhibited lanthanide‐evoked TRPC5‐mediated current in whole‐cell and outside‐out patch recordings. In differentiated 3T3‐L1 cells, it inhibited constitutive and lanthanide‐evoked calcium entry through endogenous TRPC5‐containing channels. The related natural flavonols, kaempferol and quercetin were less potent inhibitors of TRPC5. Myricetin and luteolin lacked effect, and apigenin was a stimulator. Based on structure–activity relationship studies with natural and synthetic flavonols, we designed 3,5,7‐trihydroxy‐2‐(2‐bromophenyl)‐4H‐chromen‐4‐one (AM12), which inhibited lanthanide‐evoked TRPC5 activity with an IC50 of 0.28 μM. AM12 also inhibited TRPC5 activity evoked by the agonist (−)‐Englerin A and was effective in excised outside‐out membrane patches, suggesting a relatively direct effect. It inhibited TRPC4 channels similarly, but its inhibitory effect on TRPC1–TRPC5 heteromeric channels was weaker. Conclusions and Implications The data suggest that galangin (a natural product from the ginger family) is a TRPC5 inhibitor and that other natural and synthetic flavonoids contain antagonist or agonist capabilities at TRPC5 and closely related channels depending on the substitution patterns of both the chromone core and the phenyl ring.
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Affiliation(s)
| | - Aisling Minard
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK
| | - Hannah J Gaunt
- School of Medicine, University of Leeds, Leeds, LS2 9JT, UK
| | - Mohamed S Amer
- School of Medicine, University of Leeds, Leeds, LS2 9JT, UK.,Clinical Physiology Department, Faculty of Medicine, Menoufiya University, Shibin Al Kawm, Egypt
| | | | - Marco Migliore
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK
| | - Sin Y Cheung
- School of Medicine, University of Leeds, Leeds, LS2 9JT, UK
| | | | | | | | | | - William D Evans
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK
| | - Ben L Green
- School of Medicine, University of Leeds, Leeds, LS2 9JT, UK
| | - Hongjun Yang
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yun You
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Jing Li
- School of Medicine, University of Leeds, Leeds, LS2 9JT, UK
| | | | - Katsuhiko Muraki
- School of Pharmacy, Aichi-Gakuin University, Nagoya, 464-8650, Japan
| | - David J Beech
- School of Medicine, University of Leeds, Leeds, LS2 9JT, UK
| | - Robin S Bon
- School of Medicine, University of Leeds, Leeds, LS2 9JT, UK.,School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK
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Bos EM, van Goor H, Joles JA, Whiteman M, Leuvenink HGD. Hydrogen sulfide: physiological properties and therapeutic potential in ischaemia. Br J Pharmacol 2016; 172:1479-93. [PMID: 25091411 DOI: 10.1111/bph.12869] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Revised: 06/19/2014] [Accepted: 07/27/2014] [Indexed: 12/19/2022] Open
Abstract
Hydrogen sulfide (H2 S) has become a molecule of high interest in recent years, and it is now recognized as the third gasotransmitter in addition to nitric oxide and carbon monoxide. In this review, we discuss the recent literature on the physiology of endogenous and exogenous H2 S, focusing upon the protective effects of hydrogen sulfide in models of hypoxia and ischaemia.
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Affiliation(s)
- Eelke M Bos
- Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; Department of Surgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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37
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Snijder PM, Frenay AR, de Boer RA, Pasch A, Hillebrands JL, Leuvenink HGD, van Goor H. Exogenous administration of thiosulfate, a donor of hydrogen sulfide, attenuates angiotensin II-induced hypertensive heart disease in rats. Br J Pharmacol 2016; 172:1494-504. [PMID: 24962324 DOI: 10.1111/bph.12825] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 06/09/2014] [Accepted: 06/15/2014] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND AND PURPOSE Hypertension is an important mediator of cardiac damage and remodelling. Hydrogen sulfide (H2S) is an endogenously produced gasotransmitter with cardioprotective properties. However, it is not yet in clinical use. We, therefore, investigated the protective effects of sodium thiosulfate (STS), a clinically applicable H2 S donor substance, in angiotensin II (Ang II)-induced hypertensive cardiac disease in rats. EXPERIMENTAL APPROACH Male Sprague Dawley rats were infused with Ang II (435 ng kg min(-1)) or saline (control) for 3 weeks via s.c. placed osmotic minipumps. During these 3 weeks, rats received i.p. injections of either STS, NaHS or vehicle (0.9% NaCl). KEY RESULTS Compared with controls, Ang II infusion caused an increase in systolic and diastolic BP with associated cardiac damage as evidenced by cardiac hypertrophy, an increase in atrial natriuretic peptide (ANP) mRNA, cardiac fibrosis and increased oxidative stress. Treatment with NaHS and STS prevented the development of hypertension and the increase in ANP mRNA levels. Furthermore, the degree of cardiac hypertrophy, the extent of histological fibrosis in combination with the expression of profibrotic genes and the levels of oxidative stress were all significantly decreased. CONCLUSIONS AND IMPLICATIONS Ang II-induced hypertensive cardiac disease can be attenuated by treatment with STS and NaHS. Although BP regulation is the most plausible mechanism of cardiac protection, the antifibrotic and antioxidant properties of released sulfide may also contribute to their effects. Our data show that H2 S might be a valuable addition to the already existing antihypertensive and cardioprotective therapies.
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Affiliation(s)
- P M Snijder
- Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Department of Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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38
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Currò D. The Modulation of Potassium Channels in the Smooth Muscle as a Therapeutic Strategy for Disorders of the Gastrointestinal Tract. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2016; 104:263-305. [PMID: 27038377 DOI: 10.1016/bs.apcsb.2015.12.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Alterations of smooth muscle contractility contribute to the pathophysiology of important functional gastrointestinal disorders (FGIDs) such as functional dyspepsia and irritable bowel syndrome. Consequently, drugs that decrease smooth muscle contractility are effective treatments for these diseases. Smooth muscle contraction is mainly triggered by Ca(2+) influx through voltage-dependent channels located in the plasma membrane. Thus, the modulation of the membrane potential results in the regulation of Ca(2+) influx and cytosolic levels. K(+) channels play fundamental roles in these processes. The open probability of K(+) channels increases in response to various stimuli, including membrane depolarization (voltage-gated K(+) [K(V)] channels) and the increase in cytosolic Ca(2+) levels (Ca(2+)-dependent K(+) [K(Ca)] channels). K(+) channel activation is mostly associated with outward K(+) currents that hyperpolarize the membrane and reduce cell excitability and contractility. In addition, some K(+) channels are open at the resting membrane potential values of the smooth muscle cells in some gut segments and contribute to set the resting membrane potential itself. The closure of these channels induces membrane depolarization and smooth muscle contraction. K(V)1.2, 1.5, 2.2, 4.3, 7.4 and 11.1, K(Ca)1.1 and 2.3, and inwardly rectifying type 6K(+) (K(ir)6) channels play the most important functional roles in the gastrointestinal smooth muscle. Activators of all these channels may theoretically relax the gastrointestinal smooth muscle and could therefore be promising new therapeutic options for FGID. The challenge of future drug research and development in this area will be to synthesize molecules selective for the channel assemblies expressed in the gastrointestinal smooth muscle.
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Affiliation(s)
- Diego Currò
- Institute of Pharmacology, School of Medicine, Catholic University of the Sacred Heart, Rome, Italy.
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39
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Wilder CDE, Masoud R, Yazar D, O'Brien BA, Eykyn TR, Curtis MJ. Contractile function assessment by intraventricular balloon alters the ability of regional ischaemia to evoke ventricular fibrillation. Br J Pharmacol 2016; 173:39-52. [PMID: 26377788 PMCID: PMC4813384 DOI: 10.1111/bph.13332] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 09/04/2015] [Accepted: 09/10/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND AND PURPOSE In drug research using the rat Langendorff heart preparation, it is possible to study left ventricular (LV) contractility using an intraventricular balloon (IVB), and arrhythmogenesis during coronary ligation-induced regional ischaemia. Assessing both concurrently would halve animal requirements. We aimed to test the validity of this approach. EXPERIMENTAL APPROACH The electrocardiogram (ECG) and LV function (IVB) were recorded during regional ischaemia of different extents in a randomized and blinded study. KEY RESULTS IVB-induced proarrhythmia was anticipated, but in hearts with an ischaemic zone (IZ) made deliberately small, an inflated IVB reduced ischaemia-induced ventricular fibrillation (VF) incidence as a trend. Repeating studies in hearts with large IZs revealed the effect to be significant. There were no changes in QT interval or other variables that might explain the effect. Insertion of an IVB that was minimally inflated had no effect on any variable compared with 'no IVB' controls. The antiarrhythmic effect of verapamil (a positive control drug) was unaffected by IVB inflation. Removal of an inflated (but not a non-inflated) IVB caused a release of lactate commensurate with reperfusion of an endocardial/subendocardial layer of IVB-induced ischaemia. This was confirmed by intracellular (31) phosphorus ((31) P) nuclear magnetic resonance (NMR) spectroscopy. CONCLUSIONS AND IMPLICATIONS IVB inflation does not inhibit VF suppression by a standard drug, but it has profound antiarrhythmic effects of its own, likely to be due to inflation-induced localized ischaemia. This means rhythm and contractility cannot be assessed concurrently by this approach, with implications for drug discovery and safety assessment.
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Affiliation(s)
| | - Radwa Masoud
- Cardiovascular
DivisionKing's College LondonLondonUK
| | - Duygu Yazar
- Cardiovascular
DivisionKing's College LondonLondonUK
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Abdulkareem ZA, Gee JMW, Cox CD, Wann KT. Knockdown of the small conductance Ca(2+) -activated K(+) channels is potently cytotoxic in breast cancer cell lines. Br J Pharmacol 2016; 173:177-90. [PMID: 26454020 PMCID: PMC4737296 DOI: 10.1111/bph.13357] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 08/27/2015] [Accepted: 09/24/2015] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND AND PURPOSE Small conductance calcium-activated potassium (KCa 2.x) channels have a widely accepted canonical function in regulating cellular excitability. In this study, we address a potential non-canonical function of KCa 2.x channels in breast cancer cell survival, using in vitro models. EXPERIMENTAL APPROACH The expression of all KCa 2.x channel isoforms was initially probed using RT-PCR, Western blotting and microarray analysis in five widely studied breast cancer cell lines. In order to assess the effect of pharmacological blockade and siRNA-mediated knockdown of KCa 2.x channels on these cell lines, we utilized MTS proliferation assays and also followed the corresponding expression of apoptotic markers. KEY RESULTS All of the breast cancer cell lines, regardless of their lineage or endocrine responsiveness, were highly sensitive to KCa 2.x channel blockade. UCL1684 caused cytotoxicity, with LD50 values in the low nanomolar range, in all cell lines. The role of KCa 2.x channels was confirmed using pharmacological inhibition and siRNA-mediated knockdown. This reduced cell viability and also reduced expression of Bcl-2 but increased expression of active caspase-7 and caspase-9. Complementary to these results, a variety of cell lines can be protected from apoptosis induced by staurosporine using the KCa 2.x channel activator CyPPA. CONCLUSIONS AND IMPLICATIONS In addition to a well-established role for KCa 2.x channels in migration, blockade of these channels was potently cytotoxic in breast cancer cell lines, pointing to modulation of KCa 2.x channels as a potential therapeutic approach to breast cancer.
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Affiliation(s)
| | - Julia MW Gee
- School of Pharmacy and Pharmaceutical SciencesCardiff UniversityCardiffCF10 3NBUK
| | - Charles D Cox
- Victor Chang Cardiac Research InstituteDarlinghurstNSW2010Australia
| | - Kenneth T Wann
- School of Pharmacy and Pharmaceutical SciencesCardiff UniversityCardiffCF10 3NBUK
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Redmond WJ, Cawston EE, Grimsey NL, Stuart J, Edington AR, Glass M, Connor M. Identification of N-arachidonoyl dopamine as a highly biased ligand at cannabinoid CB1 receptors. Br J Pharmacol 2016; 173:115-27. [PMID: 26398720 PMCID: PMC4813372 DOI: 10.1111/bph.13341] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Revised: 09/13/2015] [Accepted: 09/17/2015] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE N-arachidonyl dopamine (NADA) has been identified as a putative endocannabinoid, but there is little information about which signalling pathways it activates. The purpose of this study was to identify the signalling pathways activated by NADA in vitro. EXPERIMENTAL APPROACH Human or rat cannabinoid CB1 receptors were expressed in AtT20, CHO or HEK 293 cells. NADA displacement of radiolabelled cannabinoids, and CB1 receptor mediated activation of K channels or ERK phosphorylation, release of intracellular calcium ([Ca]i ) and modulation of adenylyl cyclase were measured in addition to NADA effects on CB1 receptor trafficking. KEY RESULTS At concentrations up to 30 μM, NADA failed to activate any signalling pathways via CB1 receptors, with the exception of mobilization of [Ca]i . The elevations of [Ca]i were insensitive to pertussis toxin, and reduced or abolished by blockers of Gq /11 -dependent processes including U73122, thapsigargin and a peptide antagonist of Gq /11 activation. Prolonged NADA incubation produced modest loss of cell surface CB1 receptors. The prototypical cannabinoid agonist CP55940 signalled as expected in all assays. CONCLUSIONS AND IMPLICATIONS NADA is an ineffective agonist at most canonical cannabinoid receptor signalling pathways, but did promote mobilization of [Ca]i via Gq -dependent processes and some CB1 receptor trafficking. This signalling profile is distinct from that of any known cannabinoid, and suggests that NADA may have a unique spectrum of effects in vivo. Our results also indicate that it may be possible to identify highly biased CB1 receptor ligands displaying a subset of the pharmacological or therapeutic effects usually attributed to CB1 ligands.
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Affiliation(s)
- William J. Redmond
- Department of Biomedical Sciences, Faculty of Medicine and Health SciencesMacquarie UniversityNSW2109Australia
| | - Erin E. Cawston
- Department of Pharmacology and Clinical Pharmacology, and Centre for Brain ResearchUniversity of AucklandAucklandNew Zealand
| | - Natasha L. Grimsey
- Department of Pharmacology and Clinical Pharmacology, and Centre for Brain ResearchUniversity of AucklandAucklandNew Zealand
| | - Jordyn Stuart
- Department of Biomedical Sciences, Faculty of Medicine and Health SciencesMacquarie UniversityNSW2109Australia
| | - Amelia R. Edington
- Department of Biomedical Sciences, Faculty of Medicine and Health SciencesMacquarie UniversityNSW2109Australia
| | - Michelle Glass
- Department of Pharmacology and Clinical Pharmacology, and Centre for Brain ResearchUniversity of AucklandAucklandNew Zealand
| | - Mark Connor
- Department of Biomedical Sciences, Faculty of Medicine and Health SciencesMacquarie UniversityNSW2109Australia
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Saponara S, Durante M, Spiga O, Mugnai P, Sgaragli G, Huong TT, Khanh PN, Son NT, Cuong NM, Fusi F. Functional, electrophysiological and molecular docking analysis of the modulation of Cav 1.2 channels in rat vascular myocytes by murrayafoline A. Br J Pharmacol 2015; 173:292-304. [PMID: 26493241 DOI: 10.1111/bph.13369] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 10/01/2015] [Accepted: 10/10/2015] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND AND PURPOSE The carbazole alkaloid murrayafoline A (MuA) enhances contractility and the Ca(2+) currents carried by the Cav 1.2 channels [ICa1.2 ] of rat cardiomyocytes. As only few drugs stimulate ICa1.2 , this study was designed to analyse the effects of MuA on vascular Cav 1.2 channels. EXPERIMENTAL APPROACH Vascular activity was assessed on rat aorta rings mounted in organ baths. Cav 1.2 Ba(2+) current [IBa1.2 ] was recorded in single rat aorta and tail artery myocytes by the patch-clamp technique. Docking at a 3D model of the rat, α1c central pore subunit of the Cav 1.2 channel was simulated in silico. KEY RESULTS In rat aorta rings MuA, at concentrations ≤14.2 μM, increased 30 mM K(+) -induced tone and shifted the concentration-response curve to K(+) to the left. Conversely, at concentrations >14.2 μM, it relaxed high K(+) depolarized rings and antagonized Bay K 8644-induced contraction. In single myocytes, MuA stimulated IBa1.2 in a concentration-dependent, bell-shaped manner; stimulation was stable, incompletely reversible upon drug washout and accompanied by a leftward shift of the voltage-dependent activation curve. MuA docked at the α1C subunit central pore differently from nifedipine and Bay K 8644, although apparently interacting with the same amino acids of the pocket. Neither Bay K 8644-induced stimulation nor nifedipine-induced block of IBa1.2 was modified by MuA. CONCLUSIONS AND IMPLICATIONS Murrayafoline A is a naturally occurring vasoactive agent able to modulate Cav 1.2 channels and dock at the α1C subunit central pore in a manner that differed from that of dihydropyridines.
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Affiliation(s)
- S Saponara
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, Siena, Italy
| | - M Durante
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, Siena, Italy
| | - O Spiga
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Siena, Italy
| | - P Mugnai
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, Siena, Italy
| | - G Sgaragli
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, Siena, Italy
| | - T T Huong
- Institute of Natural Products Chemistry, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - P N Khanh
- Institute of Natural Products Chemistry, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - N T Son
- Institute of Natural Products Chemistry, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - N M Cuong
- Institute of Natural Products Chemistry, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - F Fusi
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, Siena, Italy
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43
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Meng G, Ma Y, Xie L, Ferro A, Ji Y. Emerging role of hydrogen sulfide in hypertension and related cardiovascular diseases. Br J Pharmacol 2015; 172:5501-11. [PMID: 25204754 PMCID: PMC4667855 DOI: 10.1111/bph.12900] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Revised: 08/18/2014] [Accepted: 08/28/2014] [Indexed: 12/31/2022] Open
Abstract
Hydrogen sulfide (H2 S) has traditionally been viewed as a highly toxic gas; however, recent studies have implicated H2 S as a third member of the gasotransmitter family, exhibiting properties similar to NO and carbon monoxide. Accumulating evidence has suggested that H2 S influences a wide range of physiological and pathological processes, among which blood vessel relaxation, cardioprotection and atherosclerosis have been particularly studied. In the cardiovascular system, H2 S production is predominantly catalyzed by cystathionine γ-lyase (CSE). Decreased endogenous H2 S levels have been found in hypertensive patients and animals, and CSE(-/-) mice develop hypertension with age, suggesting that a deficiency in H2 S contributes importantly to BP regulation. H2 S supplementation attenuates hypertension in different hypertensive animal models. The mechanism by which H2 S was originally proposed to attenuate hypertension was by virtue of its action on vascular tone, which may be related to effects on different ion channels. Both H2 S and NO cause vasodilatation and there is cross-talk between these two molecules to regulate BP. Suppression of oxidative stress may also contribute to antihypertensive effects of H2 S. This review also summarizes the state of research on H2 S and hypertension in China. A better understanding of the role of H2 S in hypertension and related cardiovascular diseases will allow novel strategies to be devised for their treatment.
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Affiliation(s)
- Guoliang Meng
- Key Laboratory of Cardiovascular Disease and Molecular Intervention, State Key Laboratory of Reproductive Medicine, Atherosclerosis Research CentreNanjing Medical UniversityNanjingChina
| | - Yan Ma
- Key Laboratory of Cardiovascular Disease and Molecular Intervention, State Key Laboratory of Reproductive Medicine, Atherosclerosis Research CentreNanjing Medical UniversityNanjingChina
| | - Liping Xie
- Key Laboratory of Cardiovascular Disease and Molecular Intervention, State Key Laboratory of Reproductive Medicine, Atherosclerosis Research CentreNanjing Medical UniversityNanjingChina
| | - Albert Ferro
- Department of Clinical PharmacologyCardiovascular DivisionSchool of MedicineKing's College LondonLondonUK
| | - Yong Ji
- Key Laboratory of Cardiovascular Disease and Molecular Intervention, State Key Laboratory of Reproductive Medicine, Atherosclerosis Research CentreNanjing Medical UniversityNanjingChina
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Abstract
This article is part of a themed section on Chinese Innovation in Cardiovascular Drug Discovery. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-23
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Affiliation(s)
- Xin Wang
- Faculty of Life SciencesThe University of ManchesterManchesterUK
| | - Yong Ji
- Atherosclerosis Research CentreNanjing Medical UniversityNanjingChina
| | - Baofeng Yang
- Department of PharmacologyHarbin Medical UniversityHarbinChina
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45
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Kargl J, Andersen L, Hasenöhrl C, Feuersinger D, Stančić A, Fauland A, Magnes C, El-Heliebi A, Lax S, Uranitsch S, Haybaeck J, Heinemann A, Schicho R. GPR55 promotes migration and adhesion of colon cancer cells indicating a role in metastasis. Br J Pharmacol 2015; 173:142-54. [PMID: 26436760 DOI: 10.1111/bph.13345] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 08/31/2015] [Accepted: 09/24/2015] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND AND PURPOSE Tumour cell migration and adhesion constitute essential features of metastasis. G-protein coupled receptor 55 (GPR55), a lysophospholipid receptor, has been shown to play an important role in carcinogenesis. Here, we investigated the involvement of GPR55 in migration and metastasis of colon cancer cells. EXPERIMENTAL APPROACH Adhesion and migration assays using the highly metastatic colon cancer cell line HCT116 and an in vivo assay of liver metastasis were performed. The GPR55 antagonist CID16020046, cannabidiol, a putative GPR55 antagonist and GPR55 siRNA were used to block GPR55 activity in HCT116 colon cancer cells. KEY RESULTS HCT116 cells showed a significant decrease in adhesion to endothelial cells and in migration after blockade with CID16020046 or cannabidiol. The inhibitory effects of CID16020046 or cannabidiol were averted by GPR55 siRNA knock down in cancer cells. The integrity of endothelial cell monolayers was increased after pretreatment of HCT116 cells with the antagonists or after GPR55 siRNA knockdown while pretreatment with lysophosphatidylinositol (LPI), the endogenous ligand of GPR55, decreased integrity of the monolayers. LPI also induced migration in GPR55 overexpressing HCT116 cells that was blocked by GPR55 antagonists. In a mouse model of metastasis, the arrest of HCT116 cancer cells in the liver was reduced after treatment with CID16020046 or cannabidiol. Increased levels of LPI (18:0) were found in colon cancer patients when compared with healthy individuals. CONCLUSIONS AND IMPLICATIONS GPR55 is involved in the migratory behaviour of colon carcinoma cells and may serve as a pharmacological target for the prevention of metastasis. © 2015 The British Pharmacological Society.
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Affiliation(s)
- J Kargl
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - L Andersen
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - C Hasenöhrl
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - D Feuersinger
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - A Stančić
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - A Fauland
- HEALTH - Institute for Biomedicine and Health Sciences, Joanneum Research Forschungsgesellschaft m.b.H., Graz, Austria
| | - C Magnes
- HEALTH - Institute for Biomedicine and Health Sciences, Joanneum Research Forschungsgesellschaft m.b.H., Graz, Austria
| | - A El-Heliebi
- Institute of Cell Biology, Histology and Embryology, Medical University of Graz, Graz, Austria.,Biobank Graz, Medical University of Graz, Graz, Austria
| | - S Lax
- Department of Pathology, General Hospital Graz West, Graz, Austria
| | - S Uranitsch
- Department of Surgery, St John of God Hospital Graz, Graz, Austria
| | - J Haybaeck
- Institute of Pathology, Medical University of Graz, Graz, Austria
| | - A Heinemann
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - R Schicho
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
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46
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Todd SM, Arnold JC. Neural correlates of interactions between cannabidiol and Δ(9) -tetrahydrocannabinol in mice: implications for medical cannabis. Br J Pharmacol 2015; 173:53-65. [PMID: 26377899 DOI: 10.1111/bph.13333] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 09/01/2015] [Accepted: 09/06/2015] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND AND PURPOSE It has been proposed that medicinal strains of cannabis and therapeutic preparations would be safer with a more balanced concentration ratio of Δ(9) -tetrahydrocannabinol (THC) to cannabidiol (CBD), as CBD reduces the adverse psychotropic effects of THC. However, our understanding of CBD and THC interactions is limited and the brain circuitry mediating interactions between CBD and THC are unknown. The aim of this study was to investigate whether CBD modulated the functional effects and c-Fos expression induced by THC, using a 1:1 dose ratio that approximates therapeutic strains of cannabis and nabiximols. EXPERIMENTAL APPROACH Male C57BL/6 mice were treated with vehicle, CBD, THC or a combination of CBD and THC (10 mg·kg(-1) i.p. for both cannabinoids) to examine effects on locomotor activity, anxiety-related behaviour, body temperature and brain c-Fos expression (a marker of neuronal activation). KEY RESULTS CBD potentiated THC-induced locomotor suppression but reduced the hypothermic and anxiogenic effects of THC. CBD alone had no effect on these measures. THC increased brain activation as measured by c-Fos expression in 11 of the 35 brain regions studied. CBD co-administration suppressed THC-induced c-Fos expression in six of these brain regions. This effect was most pronounced in the medial preoptic nucleus and lateral periaqueductal gray. Treatment with CBD alone diminished c-Fos expression only in the central nucleus of the amygdala compared with vehicle. CONCLUSIONS AND IMPLICATIONS These data confirm that CBD modulated the pharmacological actions of THC and provide new information regarding brain regions involved in the interaction between CBD and THC.
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Affiliation(s)
- S M Todd
- Brain and Mind Centre, University of Sydney, Sydney, Australia.,Discipline of Pharmacology, School of Medical Science, University of Sydney, Sydney, Australia
| | - J C Arnold
- Brain and Mind Centre, University of Sydney, Sydney, Australia.,Discipline of Pharmacology, School of Medical Science, University of Sydney, Sydney, Australia
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Sengmany K, Gregory KJ. Metabotropic glutamate receptor subtype 5: molecular pharmacology, allosteric modulation and stimulus bias. Br J Pharmacol 2015; 173:3001-17. [PMID: 26276909 DOI: 10.1111/bph.13281] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 06/30/2015] [Accepted: 07/26/2015] [Indexed: 12/12/2022] Open
Abstract
The metabotropic glutamate receptor subtype 5 (mGlu5 ) is a family C GPCR that has been implicated in various neuronal processes and, consequently, in several CNS disorders. Over the past few decades, GPCR-based drug discovery, including that for mGlu5 receptors, has turned considerable attention to targeting allosteric binding sites. Modulation of endogenous agonists by allosteric ligands offers the advantages of spatial and temporal fine-tuning of receptor activity, increased selectivity and reduced adverse effects with the potential to elicit improved clinical outcomes. Further, with greater appreciation of the multifaceted nature of the transduction of mGlu5 receptor signalling, it is increasingly apparent that drug discovery must take into consideration unique receptor conformations and the potential for stimulus-bias. This novel paradigm proposes that different ligands may differentially modulate distinct signalling pathways arising from the same receptor. We review our current understanding of the complexities of mGlu5 receptor signalling and regulation, and how these relate to allosteric ligands. Ultimately, a deeper appreciation of these relationships will provide the foundation for targeted drug design of compounds with increased selectivity, not only for the desired receptor but also for the desired signalling outcome from the receptor. Linked Articles This article is part of a themed section on Molecular Pharmacology of G Protein-Coupled Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v173.20/issuetoc.
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Affiliation(s)
- K Sengmany
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, VIC, Australia
| | - K J Gregory
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, VIC, Australia.
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Miyazaki-Komine K, Takai Y, Huang P, Kusano-Arai O, Iwanari H, Misu T, Koda K, Mitomo K, Sakihama T, Toyama Y, Fujihara K, Hamakubo T, Yasui M, Abe Y. High avidity chimeric monoclonal antibodies against the extracellular domains of human aquaporin-4 competing with the neuromyelitis optica autoantibody, NMO-IgG. Br J Pharmacol 2015; 173:103-14. [PMID: 26398585 DOI: 10.1111/bph.13340] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 09/15/2015] [Accepted: 09/18/2015] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Most of the cases of neuromyelitis optica (NMO) are characterized by the presence of an autoantibody, NMO-IgG, which recognizes the extracellular domains of the water channel, aquaporin-4. Binding of NMO-IgG to aquaporin-4 expressed in end-feet of astrocytes leads to complement-dependent disruption of astrocytes followed by demyelination. One therapeutic option for NMO is to prevent the binding of NMO-IgG to aquaporin-4, using high-avidity, non-pathogenic-chimeric, monoclonal antibodies to this water channel. We describe here the development of such antibodies. EXPERIMENTAL APPROACH cDNAs encoding variable regions of heavy and light chains of monoclonal antibodies against the extracellular domains of human aquaporin-4 were cloned from hybridoma total RNA and fused to those encoding constant regions of human IgG1 and Igκ respectively. Then mammalian expression vectors were constructed to establish stable cell lines secreting mature chimeric antibodies. KEY RESULTS Original monoclonal antibodies showed high avidity binding to human aquaporin-4, as determined by ELISA. Live imaging using Alexa-Fluor-555-labelled antibodies revealed that the antibody D15107 more rapidly bound to cells expressing human aquaporin-4 than others and strongly enhanced endocytosis of this water channel, while D12092 also bound rapidly to human aquaporin-4 but enhanced endocytosis to a lesser degree. Chimeric D15107 prevented complement-dependent cytotoxicity induced by NMO-IgG from patient sera in vitro. CONCLUSIONS AND IMPLICATIONS We have established non-pathogenic, high-avidity, chimeric antibodies against the extracellular domains of human aquaporin-4, which provide a novel therapeutic option for preventing the progress and recurrence of NMO/NMO spectrum disorders.
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Affiliation(s)
- Kaori Miyazaki-Komine
- Department of Pharmacology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.,Department of Orthopaedic Surgery, School of Medicine, Keio University, Tokyo, Japan
| | - Yoshiki Takai
- Department of Neurology, Tohoku University School of Medicine, 1-1 Seiryomachi, Aoba-ku, Sendai, 980-8574, Japan
| | - Ping Huang
- Department of Pharmacology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Osamu Kusano-Arai
- Quantitative Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8904, Japan.,Institute of Immunology Co., Ltd., 1-1-10 Koraku, Bunkyo-ku, Tokyo, 112-0004, Japan
| | - Hiroko Iwanari
- Quantitative Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8904, Japan
| | - Tatsuro Misu
- Department of Multiple Sclerosis Therapeutics, Tohoku University Graduate School of Medicine, 1-1 Seiryomachi, Aoba-ku, Sendai, 980-8574, Japan
| | - Katsushi Koda
- Research and Development Division, Perseus Proteomics Inc., 4-7-6 Komaba, Meguro-ku, Tokyo, 153-0041, Japan
| | - Katsuyuki Mitomo
- Research and Development Division, Perseus Proteomics Inc., 4-7-6 Komaba, Meguro-ku, Tokyo, 153-0041, Japan
| | - Toshiko Sakihama
- Quantitative Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8904, Japan
| | - Yoshiaki Toyama
- Department of Orthopaedic Surgery, School of Medicine, Keio University, Tokyo, Japan
| | - Kazuo Fujihara
- Department of Multiple Sclerosis Therapeutics, Tohoku University Graduate School of Medicine, 1-1 Seiryomachi, Aoba-ku, Sendai, 980-8574, Japan
| | - Takao Hamakubo
- Quantitative Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8904, Japan
| | - Masato Yasui
- Department of Pharmacology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.,Keio Advanced Research Center for Water Biology and Medicine, Keio University, Tokyo, Japan
| | - Yoichiro Abe
- Department of Pharmacology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.,Keio Advanced Research Center for Water Biology and Medicine, Keio University, Tokyo, Japan
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49
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McPartland JM, Duncan M, Di Marzo V, Pertwee RG. Are cannabidiol and Δ(9) -tetrahydrocannabivarin negative modulators of the endocannabinoid system? A systematic review. Br J Pharmacol 2015; 172:737-53. [PMID: 25257544 DOI: 10.1111/bph.12944] [Citation(s) in RCA: 352] [Impact Index Per Article: 39.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 09/12/2014] [Accepted: 09/16/2014] [Indexed: 12/12/2022] Open
Abstract
Based upon evidence that the therapeutic properties of Cannabis preparations are not solely dependent upon the presence of Δ(9) -tetrahydrocannabinol (THC), pharmacological studies have been recently carried out with other plant cannabinoids (phytocannabinoids), particularly cannabidiol (CBD) and Δ(9) -tetrahydrocannabivarin (THCV). Results from some of these studies have fostered the view that CBD and THCV modulate the effects of THC via direct blockade of cannabinoid CB1 receptors, thus behaving like first-generation CB1 receptor inverse agonists, such as rimonabant. Here, we review in vitro and ex vivo mechanistic studies of CBD and THCV, and synthesize data from these studies in a meta-analysis. Synthesized data regarding mechanisms are then used to interpret results from recent pre-clinical animal studies and clinical trials. The evidence indicates that CBD and THCV are not rimonabant-like in their action and thus appear very unlikely to produce unwanted CNS effects. They exhibit markedly disparate pharmacological profiles particularly at CB1 receptors: CBD is a very low-affinity CB1 ligand that can nevertheless affect CB1 receptor activity in vivo in an indirect manner, while THCV is a high-affinity CB1 receptor ligand and potent antagonist in vitro and yet only occasionally produces effects in vivo resulting from CB1 receptor antagonism. THCV has also high affinity for CB2 receptors and signals as a partial agonist, differing from both CBD and rimonabant. These cannabinoids illustrate how in vitro mechanistic studies do not always predict in vivo pharmacology and underlie the necessity of testing compounds in vivo before drawing any conclusion on their functional activity at a given target.
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Affiliation(s)
- John M McPartland
- Division of Molecular Biology, GW Pharmaceuticals, Salisbury, Wiltshire, UK
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Bai J, Ding W, Kojima A, Seto T, Matsuura H. Putative binding sites for arachidonic acid on the human cardiac Kv 1.5 channel. Br J Pharmacol 2015; 172:5281-92. [PMID: 26292661 PMCID: PMC5341216 DOI: 10.1111/bph.13314] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 08/01/2015] [Accepted: 08/18/2015] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND AND PURPOSE In human heart, the Kv 1.5 channel contributes to repolarization of atrial action potentials. This study examined the electrophysiological and molecular mechanisms underlying arachidonic acid (AA)-induced inhibition of the human Kv 1.5 (hKv 1.5) channel. EXPERIMENTAL APPROACH Site-directed mutagenesis was conducted to mutate amino acids that reside within the pore domain of the hKv 1.5 channel. Whole-cell patch-clamp method was used to record membrane currents through wild type and mutant hKv 1.5 channels heterologously expressed in CHO cells. Computer docking simulation was conducted to predict the putative binding site(s) of AA in an open-state model of the Kv 1.5 channel. KEY RESULTS The hKv 1.5 current was minimally affected at the onset of depolarization but was progressively reduced during depolarization by the presence of AA, suggesting that AA acts as an open-channel blocker. AA itself affected the channel at extracellular sites independently of its metabolites and signalling pathways. The blocking effect of AA was attenuated at pH 8.0 but not at pH 6.4. The blocking action of AA developed rather rapidly by co-expression of Kv β1.3. The AA-induced block was significantly attenuated in H463C, T480A, R487V, I502A, I508A, V512A and V516A, but not in T462C, A501V and L510A mutants of the hKv 1.5 channel. Docking simulation predicted that H463, T480, R487, I508, V512 and V516 are potentially accessible for interaction with AA. CONCLUSIONS AND IMPLICATIONS AA itself interacts with multiple amino acids located in the pore domain of the hKv 1.5 channel. These findings may provide useful information for future development of selective blockers of hKv 1.5 channels.
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Affiliation(s)
- Jia‐Yu Bai
- Department of PhysiologyShiga University of Medical ScienceOtsuJapan
| | - Wei‐Guang Ding
- Department of PhysiologyShiga University of Medical ScienceOtsuJapan
| | - Akiko Kojima
- Department of AnesthesiologyShiga University of Medical ScienceOtsuJapan
| | - Tomoyoshi Seto
- Department of AnesthesiologyShiga University of Medical ScienceOtsuJapan
| | - Hiroshi Matsuura
- Department of PhysiologyShiga University of Medical ScienceOtsuJapan
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