1
|
Holt LM, Gyles TM, Parise EM, Minier-Toribio A, Rivera M, Markovic T, Yeh SY, Nestler EJ. Astrocytic CREB in nucleus accumbens promotes susceptibility to chronic stress. Biol Psychiatry 2024:S0006-3223(24)01626-3. [PMID: 39369762 DOI: 10.1016/j.biopsych.2024.09.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 09/18/2024] [Accepted: 09/25/2024] [Indexed: 10/08/2024]
Abstract
BACKGROUND Increasing evidence implicates astrocytes in stress and depression in both rodent models and human Major Depressive Disorder (MDD). Despite this, little is known about the transcriptional responses to stress of astrocytes within the nucleus accumbens (NAc), a key brain reward region, and their influence on behavioral outcomes. METHODS We used whole cell sorting, RNA-sequencing, and bioinformatic analyses to investigate the NAc astrocyte transcriptome in male mice in response to chronic social defeat stress (CSDS). Immunohistochemistry was used to determine stress-induced changes in astrocytic CREB within the NAc. Finally, astrocytic regulation of depression-like behavior was investigated using viral-mediated manipulation of CREB in combination with CSDS. RESULTS We found a robust transcriptional response in NAc astrocytes to CSDS in stressed mice, with changes seen in both stress-susceptible and stress-resilient animals. Bioinformatic analysis revealed CREB, a transcription factor widely studied in neurons, as one of the top-predicted upstream regulators of the NAc astrocyte transcriptome, with opposite activation states implicated in resilient vs. susceptible mice. This bioinformatic deduction was confirmed at the protein level with immunohistochemistry. Moreover, NAc astrocyte morphological complexity correlated with CREB activation and was reduced selectively in astrocytes of resilient mice. Viral overexpression of CREB selectively in NAc astrocytes promoted susceptibility to chronic stress. CONCLUSIONS Together, our data demonstrate that the astrocyte transcriptome responds robustly to CSDS and that transcriptional regulation in astrocytes contributes to depressive-like behaviors. A better understanding of transcriptional regulation in astrocytes may reveal unknown molecular mechanisms underlying neuropsychiatric disorders.
Collapse
Affiliation(s)
- Leanne M Holt
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Trevonn M Gyles
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Eric M Parise
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Angelica Minier-Toribio
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Matthew Rivera
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Tamara Markovic
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Szu-Ying Yeh
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Eric J Nestler
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA.
| |
Collapse
|
2
|
Zhou X, Zhao C, Xu H, Xu Y, Zhan L, Wang P, He J, Lu T, Gu Y, Yang Y, Xu C, Chen Y, Liu Y, Zeng Y, Tian F, Chen Q, Xie X, Liu J, Hu H, Li J, Zheng Y, Guo J, Gao Z. Pharmacological inhibition of Kir4.1 evokes rapid-onset antidepressant responses. Nat Chem Biol 2024; 20:857-866. [PMID: 38355723 DOI: 10.1038/s41589-024-01555-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 01/15/2024] [Indexed: 02/16/2024]
Abstract
Major depressive disorder, a prevalent and severe psychiatric condition, necessitates development of new and fast-acting antidepressants. Genetic suppression of astrocytic inwardly rectifying potassium channel 4.1 (Kir4.1) in the lateral habenula ameliorates depression-like phenotypes in mice. However, Kir4.1 remains an elusive drug target for depression. Here, we discovered a series of Kir4.1 inhibitors through high-throughput screening. Lys05, the most potent one thus far, effectively suppressed native Kir4.1 channels while displaying high selectivity against established targets for rapid-onset antidepressants. Cryogenic-electron microscopy structures combined with electrophysiological characterizations revealed Lys05 directly binds in the central cavity of Kir4.1. Notably, a single dose of Lys05 reversed the Kir4.1-driven depression-like phenotype and exerted rapid-onset (as early as 1 hour) antidepressant actions in multiple canonical depression rodent models with efficacy comparable to that of (S)-ketamine. Overall, we provided a proof of concept that Kir4.1 is a promising target for rapid-onset antidepressant effects.
Collapse
Affiliation(s)
- Xiaoyu Zhou
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- College of Pharmacy, University of Chinese Academy of Sciences, Beijing, China
| | - Cheng Zhao
- Department of Biophysics and Department of Neurology of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Haiyan Xu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, China
| | - Yixiang Xu
- State Key Laboratory of Bioreactor Engineering, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai, China
| | - Li Zhan
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Pei Wang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Jingyi He
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- School of Pharmacy, Henan University, Kaifeng, China
| | - Taotao Lu
- State Key Laboratory of Bioreactor Engineering, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai, China
| | - Yueling Gu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Yan Yang
- Liangzhu Laboratory, Zhejiang University School of Medicine, New Cornerstone Science Laboratory, Zhejiang University, Hangzhou, China
| | - Chanjuan Xu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Yiyang Chen
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Yuxuan Liu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Yue Zeng
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Fuyun Tian
- Zhongshan Institute for Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Zhongshan, China
| | - Qian Chen
- Department of Biophysics and Department of Neurology of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xin Xie
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Jianfeng Liu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Hailan Hu
- Liangzhu Laboratory, Zhejiang University School of Medicine, New Cornerstone Science Laboratory, Zhejiang University, Hangzhou, China
| | - Jian Li
- State Key Laboratory of Bioreactor Engineering, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai, China
| | - Yueming Zheng
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
| | - Jiangtao Guo
- Department of Biophysics and Department of Neurology of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
| | - Zhaobing Gao
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
- College of Pharmacy, University of Chinese Academy of Sciences, Beijing, China.
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, China.
- School of Pharmacy, Henan University, Kaifeng, China.
- Zhongshan Institute for Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Zhongshan, China.
| |
Collapse
|
3
|
Holt LM, Gyles TM, Parise EM, Minier-Toribio A, Markovic T, Rivera M, Yeh SY, Nestler EJ. Astrocytic CREB in nucleus accumbens promotes susceptibility to chronic stress. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.15.575728. [PMID: 38293227 PMCID: PMC10827054 DOI: 10.1101/2024.01.15.575728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Background Increasing evidence implicates astrocytes in stress and depression in both rodent models and human Major Depressive Disorder (MDD). Despite this, little is known about the transcriptional responses to stress of astrocytes within the nucleus accumbens (NAc), a key brain reward region, and their influence on behavioral outcomes. Methods We used whole cell sorting, RNA-sequencing, and bioinformatic analyses to investigate the NAc astrocyte transcriptome in male mice in response to chronic social defeat stress (CSDS). Immunohistochemistry was used to determine stress-induced changes in astrocytic CREB within the NAc. Finally, astrocytic regulation of depression-like behavior was investigated using viral-mediated manipulation of CREB in combination with CSDS. Results We found a robust transcriptional response in NAc astrocytes to CSDS in stressed mice, with changes seen in both stress-susceptible and stress-resilient animals. Bioinformatic analysis revealed CREB, a transcription factor widely studied in neurons, as one of the top-predicted upstream regulators of the NAc astrocyte transcriptome, with opposite activation states seen in resilient versus susceptible mice. This bioinformatic result was confirmed at the protein level with immunohistochemistry. Viral overexpression of CREB selectively in NAc astrocytes promoted susceptibility to chronic stress. Conclusions Together, our data demonstrate that the astrocyte transcriptome responds robustly to CSDS and, for the first time, that transcriptional regulation in astrocytes contributes to depressive-like behaviors. A better understanding of transcriptional regulation in astrocytes may reveal unknown molecular mechanisms underlying neuropsychiatric disorders.
Collapse
Affiliation(s)
- Leanne M. Holt
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Trevonn M Gyles
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Eric M. Parise
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Angelica Minier-Toribio
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Tamara Markovic
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Matthew Rivera
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Szu-Ying Yeh
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Eric J. Nestler
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| |
Collapse
|
4
|
Božić M, Pirnat S, Fink K, Potokar M, Kreft M, Zorec R, Stenovec M. Ketamine Reduces the Surface Density of the Astroglial Kir4.1 Channel and Inhibits Voltage-Activated Currents in a Manner Similar to the Action of Ba 2+ on K + Currents. Cells 2023; 12:1360. [PMID: 37408194 DOI: 10.3390/cells12101360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 05/04/2023] [Accepted: 05/05/2023] [Indexed: 07/07/2023] Open
Abstract
A single sub-anesthetic dose of ketamine evokes rapid and long-lasting beneficial effects in patients with a major depressive disorder. However, the mechanisms underlying this effect are unknown. It has been proposed that astrocyte dysregulation of extracellular K+ concentration ([K+]o) alters neuronal excitability, thus contributing to depression. We examined how ketamine affects inwardly rectifying K+ channel Kir4.1, the principal regulator of K+ buffering and neuronal excitability in the brain. Cultured rat cortical astrocytes were transfected with plasmid-encoding fluorescently tagged Kir4.1 (Kir4.1-EGFP) to monitor the mobility of Kir4.1-EGFP vesicles at rest and after ketamine treatment (2.5 or 25 µM). Short-term (30 min) ketamine treatment reduced the mobility of Kir4.1-EGFP vesicles compared with the vehicle-treated controls (p < 0.05). Astrocyte treatment (24 h) with dbcAMP (dibutyryl cyclic adenosine 5'-monophosphate, 1 mM) or [K+]o (15 mM), which increases intracellular cAMP, mimicked the ketamine-evoked reduction of mobility. Live cell immunolabelling and patch-clamp measurements in cultured mouse astrocytes revealed that short-term ketamine treatment reduced the surface density of Kir4.1 and inhibited voltage-activated currents similar to Ba2+ (300 µM), a Kir4.1 blocker. Thus, ketamine attenuates Kir4.1 vesicle mobility, likely via a cAMP-dependent mechanism, reduces Kir4.1 surface density, and inhibits voltage-activated currents similar to Ba2+, known to block Kir4.1 channels.
Collapse
Affiliation(s)
- Mićo Božić
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia
- Department of Medical Oncology, Institute of Oncology Ljubljana, Zaloška 2, 1000 Ljubljana, Slovenia
| | - Samo Pirnat
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia
- Celica Biomedical, Tehnološki Park 24, 1000 Ljubljana, Slovenia
| | - Katja Fink
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia
| | - Maja Potokar
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia
- Celica Biomedical, Tehnološki Park 24, 1000 Ljubljana, Slovenia
| | - Marko Kreft
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia
- Celica Biomedical, Tehnološki Park 24, 1000 Ljubljana, Slovenia
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia
- Celica Biomedical, Tehnološki Park 24, 1000 Ljubljana, Slovenia
| | - Matjaž Stenovec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia
- Celica Biomedical, Tehnološki Park 24, 1000 Ljubljana, Slovenia
| |
Collapse
|
5
|
Wang N, Zhou L, Shao CY, Wang XT, Zhang N, Ma J, Hu HL, Wang Y, Qiu M, Shen Y. Potassium channel K ir 4.1 regulates oligodendrocyte differentiation via intracellular pH regulation. Glia 2022; 70:2093-2107. [PMID: 35775976 DOI: 10.1002/glia.24240] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 06/06/2022] [Accepted: 06/24/2022] [Indexed: 11/10/2022]
Abstract
In humans, loss-of-function mutations of Kcnj10 in SeSAME/EAST syndrome, which encodes the inwardly rectifying K+ channel 4.1 (Kir 4.1), causes progressive neurological decline. Despite its rich expression in oligodendrocyte (OL) lineage cells and an emerging link with demyelinating disease, the function of Kir 4.1 in OLs is unclear. Here we show a novel role of Kir 4.1 in OL development. Kir 4.1 expression is markedly greater in OLs than in OL precursor cells (OPCs), and the down-regulation of Kir 4.1 impairs OL maturation by affecting OPC differentiation. Interestingly, Kir 4.1 regulates the intracellular pH of OPCs and OLs via the Na+ /H+ exchanger, which underlies impeded OPC differentiation by Kir 4.1 inhibition. Furthermore, Kir 4.1 regulates GSK3β and SOX10, two molecules critical to OPC development. Collectively, our work opens a new avenue to understanding the functions of Kir 4.1 and intracellular pH in OLs.
Collapse
Affiliation(s)
- Na Wang
- Department of Physiology and Department of Neurology of the First Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Liang Zhou
- Department of Physiology and Department of Neurology of the First Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Brain Science, Guizhou Institution of Higher Education, Zunyi Medical University, Zunyi, China
| | - Chong-Yu Shao
- Department of Physiology and Department of Neurology of the First Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Xin-Tai Wang
- Department of Physiology and Department of Neurology of the First Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Nan Zhang
- Key Laboratory of Cranial Cerebral Diseases, Department of Neurobiology of Basic Medical College, Ningxia Medical University, Yinchuan, China
| | - Jiao Ma
- Key Laboratory of Cranial Cerebral Diseases, Department of Neurobiology of Basic Medical College, Ningxia Medical University, Yinchuan, China
| | - Hai-Lan Hu
- Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou, China
| | - Yin Wang
- Key Laboratory of Cranial Cerebral Diseases, Department of Neurobiology of Basic Medical College, Ningxia Medical University, Yinchuan, China
| | - Mengsheng Qiu
- Institute of Life Sciences, Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Ying Shen
- Department of Physiology and Department of Neurology of the First Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| |
Collapse
|
6
|
Inhibitory Effectiveness in Delayed-Rectifier Potassium Current Caused by Vortioxetine, Known to Be a Novel Antidepressant. Biomedicines 2022; 10:biomedicines10061318. [PMID: 35740340 PMCID: PMC9220334 DOI: 10.3390/biomedicines10061318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/25/2022] [Accepted: 06/01/2022] [Indexed: 01/27/2023] Open
Abstract
Vortioxetine (VOR) is recognized to exert antidepressant actions. However, whether this drug modifies ionic currents in excitable cells remains unclear. The aim of this study was to explore the electrophysiological effects of VOR and other related compounds in pituitary GH3 cells and in Neuro-2a cells. VOR suppressed the delayed-rectifier K+ current (IK(DR)) in a concentration-, time-, and state-dependent manner. Effective IC50 values needed to inhibit peak and sustained IK(DR) were computed to be 31.2 and 8.5 μM, respectively, while the KD value estimated from minimal binding scheme was 7.9 μM. Cell exposure to serotonin (10 μM) alone failed to alter IK(DR), while fluoxetine (10 μM), a compound structurally similar to VOR, mildly suppressed current amplitude. In continued presence of VOR, neither further addition of propranolol nor risperidone reversed VOR-mediated inhibition of IK(DR). Increasing VOR concentration not only depressed IK(DR) conductance but also shifted toward the hyperpolarized potential. As the VOR concentration was raised, the recovery of IK(DR) block became slowed. The IK(DR) activated by a downsloping ramp was suppressed by its presence. The inhibition of IK(DR) by a train pulse was enhanced during exposure to VOR. In Neuro-2a cells, this drug decreased IK(DR). Overall, inhibitory effects of VOR on ionic currents might constitute another underlying mechanism of its actions.
Collapse
|
7
|
McClenahan SJ, Kent CN, Kharade SV, Isaeva E, Williams JC, Han C, Terker A, Gresham R, Lazarenko RM, Days EL, Romaine IM, Bauer JA, Boutaud O, Sulikowski GA, Harris R, Weaver CD, Staruschenko A, Lindsley CW, Denton JS. VU6036720: The First Potent and Selective In Vitro Inhibitor of Heteromeric Kir4.1/5.1 Inward Rectifier Potassium Channels. Mol Pharmacol 2022; 101:357-370. [PMID: 35246480 PMCID: PMC9092466 DOI: 10.1124/molpharm.121.000464] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 02/14/2022] [Indexed: 01/14/2023] Open
Abstract
Heteromeric Kir4.1/Kir5.1 (KCNJ10/KCNJ16) inward rectifier potassium (Kir) channels play key roles in the brain and kidney, but pharmacological tools for probing their physiology and therapeutic potential have not been developed. Here, we report the discovery, in a high-throughput screening of 80,475 compounds, of the moderately potent and selective inhibitor VU0493690, which we selected for characterization and chemical optimization. VU0493690 concentration-dependently inhibits Kir4.1/5.1 with an IC50 of 0.96 μM and exhibits at least 10-fold selectivity over Kir4.1 and ten other Kir channels. Multidimensional chemical optimization of VU0493690 led to the development of VU6036720, the most potent (IC50 = 0.24 μM) and selective (>40-fold over Kir4.1) Kir4.1/5.1 inhibitor reported to date. Cell-attached patch single-channel recordings revealed that VU6036720 inhibits Kir4.1/5.1 activity through a reduction of channel open-state probability and single-channel current amplitude. Elevating extracellular potassium ion by 20 mM shifted the IC50 6.8-fold, suggesting that VU6036720 is a pore blocker that binds in the ion-conduction pathway. Mutation of the "rectification controller" asparagine 161 to glutamate (N161E), which is equivalent to small-molecule binding sites in other Kir channels, led to a strong reduction of inhibition by VU6036720. Renal clearance studies in mice failed to show a diuretic response that would be consistent with inhibition of Kir4.1/5.1 in the renal tubule. Drug metabolism and pharmacokinetics profiling revealed that high VU6036720 clearance and plasma protein binding may prevent target engagement in vivo. In conclusion, VU6036720 represents the current state-of-the-art Kir4.1/5.1 inhibitor that should be useful for probing the functions of Kir4.1/5.1 in vitro and ex vivo. SIGNIFICANCE STATEMENT: Heteromeric inward rectifier potassium (Kir) channels comprising Kir4.1 and Kir5.1 subunits play important roles in renal and neural physiology and may represent inhibitory drug targets for hypertension and edema. Herein, we employ high-throughput compound library screening, patch clamp electrophysiology, and medicinal chemistry to develop and characterize the first potent and specific in vitro inhibitor of Kir4.1/5.1, VU6036720, which provides proof-of-concept that drug-like inhibitors of this channel may be developed.
Collapse
Affiliation(s)
- Samantha J McClenahan
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Caitlin N Kent
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Sujay V Kharade
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Elena Isaeva
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Jade C Williams
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Changho Han
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Andrew Terker
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Robert Gresham
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Roman M Lazarenko
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Emily L Days
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Ian M Romaine
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Joshua A Bauer
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Olivier Boutaud
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Gary A Sulikowski
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Raymond Harris
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - C David Weaver
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Alexander Staruschenko
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Craig W Lindsley
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Jerod S Denton
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| |
Collapse
|
8
|
Cathomas F, Holt LM, Parise EM, Liu J, Murrough JW, Casaccia P, Nestler EJ, Russo SJ. Beyond the neuron: Role of non-neuronal cells in stress disorders. Neuron 2022; 110:1116-1138. [PMID: 35182484 PMCID: PMC8989648 DOI: 10.1016/j.neuron.2022.01.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 12/15/2021] [Accepted: 01/24/2022] [Indexed: 12/11/2022]
Abstract
Stress disorders are leading causes of disease burden in the U.S. and worldwide, yet available therapies are fully effective in less than half of all individuals with these disorders. Although to date, much of the focus has been on neuron-intrinsic mechanisms, emerging evidence suggests that chronic stress can affect a wide range of cell types in the brain and periphery, which are linked to maladaptive behavioral outcomes. Here, we synthesize emerging literature and discuss mechanisms of how non-neuronal cells in limbic regions of brain interface at synapses, the neurovascular unit, and other sites of intercellular communication to mediate the deleterious, or adaptive (i.e., pro-resilient), effects of chronic stress in rodent models and in human stress-related disorders. We believe that such an approach may one day allow us to adopt a holistic "whole body" approach to stress disorder research, which could lead to more precise diagnostic tests and personalized treatment strategies. Stress is a major risk factor for many psychiatric disorders. Cathomas et al. review new insight into how non-neuronal cells mediate the deleterious effects, as well as the adaptive, protective effects, of stress in rodent models and human stress-related disorders.
Collapse
Affiliation(s)
- Flurin Cathomas
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Leanne M Holt
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Eric M Parise
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jia Liu
- Neuroscience Initiative, Advanced Science Research Center, Program in Biology and Biochemistry at The Graduate Center of The City University of New York, New York, NY, USA
| | - James W Murrough
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Patrizia Casaccia
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Neuroscience Initiative, Advanced Science Research Center, Program in Biology and Biochemistry at The Graduate Center of The City University of New York, New York, NY, USA
| | - Eric J Nestler
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Scott J Russo
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| |
Collapse
|
9
|
Isaeva E, Bohovyk R, Fedoriuk M, Shalygin A, Klemens CA, Zietara A, Levchenko V, Denton JS, Staruschenko A, Palygin O. Crosstalk between ENaC and basolateral K ir 4.1/K ir 5.1 channels in the cortical collecting duct. Br J Pharmacol 2021; 179:2953-2968. [PMID: 34904226 DOI: 10.1111/bph.15779] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 10/06/2021] [Accepted: 12/06/2021] [Indexed: 11/02/2022] Open
Abstract
BACKGROUND AND PURPOSE Inwardly rectifying K+ (Kir ) channels located on the basolateral membrane of epithelial cells of the distal nephron play a crucial role in K+ handling and blood pressure control, making these channels an attractive target for the treatment of hypertension. The purpose of the present study was to determine how the inhibition of basolateral Kir 4.1/Kir 5.1 heteromeric K+ channel affects epithelial sodium channel (ENaC)-mediated Na+ transport in the principal cells of cortical collecting duct (CCD). EXPERIMENTAL APPROACH The effect of fluoxetine, amitriptyline, and recently developed Kir inhibitor, VU0134992, on the activity of Kir 4.1, Kir 4.1/Kir 5.1, and ENaC were tested using electrophysiological approaches in Chinese hamster ovary (CHO) cells transfected with respective channel subunits, cultured polarized epithelial mCCDcl1 cells, and freshly isolated rat and human CCD tubules. To test the effect of pharmacological Kir 4.1/Kir 5.1 inhibition on electrolyte homeostasis in vivo and corresponding changes in distal tubule transport, Dahl salt-sensitive rats were injected with amitriptyline (15 mg kg-1 day-1 ) for three days. KEY RESULTS We found that inhibition of Kir 4.1/Kir 5.1, but not Kir 4.1 channel, depolarizes cell membrane, induces the elevation of intracellular Ca2+ concentration, and suppresses ENaC activity. Furthermore, we demonstrate that amitriptyline administration leads to a significant drop in plasma K+ level, triggering sodium excretion and diuresis. CONCLUSION AND IMPLICATIONS Present data uncovers a specific role of the Kir 4.1/Kir 5.1 channel in the modulation of ENaC activity and emphasizes the potential for using Kir 4.1/Kir 5.1 inhibitors to regulate electrolyte homeostasis and blood pressure.
Collapse
Affiliation(s)
- Elena Isaeva
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Cellular Membranology, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Ruslan Bohovyk
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Cellular Membranology, Bogomoletz Institute of Physiology, Kyiv, Ukraine.,Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - Mykhailo Fedoriuk
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Cellular Membranology, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Alexey Shalygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Institute of Cytology of the Russian Academy of Sciences, St. Petersburg, Russia
| | - Christine A Klemens
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - Adrian Zietara
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - Vladislav Levchenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - Jerod S Denton
- Department of Anesthesiology and Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alexander Staruschenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, USA.,Clement J. Zablocki VA Medical Center, Milwaukee, WI, USA.,Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, USA
| |
Collapse
|
10
|
Stenovec M, Li B, Verkhratsky A, Zorec R. Ketamine Action on Astrocytes Provides New Insights into Rapid Antidepressant Mechanisms. ADVANCES IN NEUROBIOLOGY 2021; 26:349-365. [PMID: 34888841 DOI: 10.1007/978-3-030-77375-5_14] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Ketamine, a non-competitive N-methyl-D-aspartate receptor (NMDAR) antagonist, exerts rapid, potent and long-lasting antidepressant effect already after a single administration of a low dose into depressed individuals. Apart from targeting neuronal NMDARs essential for synaptic transmission, ketamine also interacts with astrocytes, the principal homoeostatic cells of the central nervous system. The cellular mechanisms underlying astrocyte-based rapid antidepressant effect are incompletely understood. Here we overview recent data that describe ketamine-dependent changes in astrocyte cytosolic cAMP activity ([cAMP]i) and ketamine-induced modifications of stimulus-evoked Ca2+ signalling. The latter regulates exocytotic release of gliosignalling molecules and stabilizes the vesicle fusion pore in a narrow configuration that obstructs cargo discharge or vesicle membrane recycling. Ketamine also instigates rapid redistribution of cholesterol in the astrocyte plasmalemma that may alter flux of cholesterol to neurones, where it is required for changes in synaptic plasticity. Finally, ketamine attenuates mobility of vesicles carrying the inward rectifying potassium channel (Kir4.1) and reduces the surface density of Kir4.1 channels that control extracellular K+ concentration, which tunes the pattern of action potential firing in neurones of lateral habenula as demonstrated in a rat model of depression. Thus, diverse, but not mutually exclusive, mechanisms act synergistically to evoke changes in synaptic plasticity leading to sustained strengthening of excitatory synapses necessary for rapid antidepressant effect of ketamine.
Collapse
Affiliation(s)
- Matjaž Stenovec
- Celica BIOMEDICAL, Ljubljana, Slovenia.,Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Baoman Li
- Practical Teaching Centre, School of Forensic Medicine, China Medical University, Shenyang, China.,Department of Poison Analysis, School of Forensic Medicine, China Medical University, Shenyang, China
| | - Alexei Verkhratsky
- Celica BIOMEDICAL, Ljubljana, Slovenia.,Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.,Achucarro Center for Neuroscience, IKERBASQUE, Bilbao, Spain
| | - Robert Zorec
- Celica BIOMEDICAL, Ljubljana, Slovenia. .,Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
| |
Collapse
|
11
|
Della Vecchia S, Marchese M, Santorelli FM, Sicca F. Kir4.1 Dysfunction in the Pathophysiology of Depression: A Systematic Review. Cells 2021; 10:2628. [PMID: 34685608 PMCID: PMC8534194 DOI: 10.3390/cells10102628] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 09/28/2021] [Accepted: 09/28/2021] [Indexed: 12/17/2022] Open
Abstract
A serotonergic dysfunction has been largely postulated as the main cause of depression, mainly due to its effective response to drugs that increase the serotonergic tone, still currently the first therapeutic line in this mood disorder. However, other dysfunctional pathomechanisms are likely involved in the disorder, and this may in part explain why some individuals with depression are resistant to serotonergic therapies. Among these, emerging evidence suggests a role for the astrocytic inward rectifier potassium channel 4.1 (Kir4.1) as an important modulator of neuronal excitability and glutamate metabolism. To discuss the relationship between Kir4.1 dysfunction and depression, a systematic review was performed according to the PRISMA statement. Searches were conducted across PubMed, Scopus, and Web of Science by two independent reviewers. Twelve studies met the inclusion criteria, analyzing Kir4.1 relationships with depression, through in vitro, in vivo, and post-mortem investigations. Increasing, yet not conclusive, evidence suggests a potential pathogenic role for Kir4.1 upregulation in depression. However, the actual contribution in the diverse subtypes of the disorder and in the comorbid conditions, for example, the epilepsy-depression comorbidity, remain elusive. Further studies are needed to better define the clinical phenotype associated with Kir4.1 dysfunction in humans and the molecular mechanisms by which it contributes to depression and implications for future treatments.
Collapse
Affiliation(s)
- Stefania Della Vecchia
- Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, Calambrone, 56128 Pisa, Italy;
- Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy
| | - Maria Marchese
- Department of Molecular Medicine, IRCCS Stella Maris Foundation, Via dei Giacinti 2, 56128 Pisa, Italy;
| | - Filippo Maria Santorelli
- Department of Molecular Medicine, IRCCS Stella Maris Foundation, Via dei Giacinti 2, 56128 Pisa, Italy;
| | - Federico Sicca
- Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, Calambrone, 56128 Pisa, Italy;
- Child Neuropsychiatric Unit, USL Centro Toscana, 59100 Prato, Italy
| |
Collapse
|
12
|
Ohno Y, Kunisawa N, Shimizu S. Emerging Roles of Astrocyte Kir4.1 Channels in the Pathogenesis and Treatment of Brain Diseases. Int J Mol Sci 2021; 22:ijms221910236. [PMID: 34638578 PMCID: PMC8508600 DOI: 10.3390/ijms221910236] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/14/2021] [Accepted: 09/16/2021] [Indexed: 12/15/2022] Open
Abstract
Inwardly rectifying Kir4.1 channels in astrocytes mediate spatial potassium (K+) buffering, a clearance mechanism for excessive extracellular K+, in tripartite synapses. In addition to K+ homeostasis, astrocytic Kir4.1 channels also play an essential role in regulating extracellular glutamate levels via coupling with glutamate transporters. Moreover, Kir4.1 channels act as novel modulators of the expression of brain-derived neurotrophic factor (BDNF) in astrocytes. Specifically, inhibition of astrocytic Kir4.1 channels elevates extracellular K+ and glutamate levels at synapses and facilitates BDNF expression in astrocytes. These changes elevate neural excitability, which may facilitate synaptic plasticity and connectivity. In this article, we summarize the functions and pharmacological features of Kir4.1 channels in astrocytes and highlight the importance of these channels in the treatment of brain diseases. Although further validation in animal models and human patients is required, astrocytic Kir4.1 channel could potentially serve as a novel therapeutic target for the treatment of depressive disorders and epilepsy.
Collapse
|
13
|
Kir Channel Molecular Physiology, Pharmacology, and Therapeutic Implications. Handb Exp Pharmacol 2021; 267:277-356. [PMID: 34345939 DOI: 10.1007/164_2021_501] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
For the past two decades several scholarly reviews have appeared on the inwardly rectifying potassium (Kir) channels. We would like to highlight two efforts in particular, which have provided comprehensive reviews of the literature up to 2010 (Hibino et al., Physiol Rev 90(1):291-366, 2010; Stanfield et al., Rev Physiol Biochem Pharmacol 145:47-179, 2002). In the past decade, great insights into the 3-D atomic resolution structures of Kir channels have begun to provide the molecular basis for their functional properties. More recently, computational studies are beginning to close the time domain gap between in silico dynamic and patch-clamp functional studies. The pharmacology of these channels has also been expanding and the dynamic structural studies provide hope that we are heading toward successful structure-based drug design for this family of K+ channels. In the present review we focus on placing the physiology and pharmacology of this K+ channel family in the context of atomic resolution structures and in providing a glimpse of the promising future of therapeutic opportunities.
Collapse
|
14
|
Ketamine Alters Functional Plasticity of Astroglia: An Implication for Antidepressant Effect. Life (Basel) 2021; 11:life11060573. [PMID: 34204579 PMCID: PMC8234122 DOI: 10.3390/life11060573] [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: 05/31/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 12/28/2022] Open
Abstract
Ketamine, a non-competitive N–methyl–d–aspartate receptor (NMDAR) antagonist, exerts a rapid, potent and long-lasting antidepressant effect, although the cellular and molecular mechanisms of this action are yet to be clarified. In addition to targeting neuronal NMDARs fundamental for synaptic transmission, ketamine also affects the function of astrocytes, the key homeostatic cells of the central nervous system that contribute to pathophysiology of major depressive disorder. Here, I review studies revealing that (sub)anesthetic doses of ketamine elevate intracellular cAMP concentration ([cAMP]i) in astrocytes, attenuate stimulus-evoked astrocyte calcium signaling, which regulates exocytotic secretion of gliosignaling molecules, and stabilize the vesicle fusion pore in a narrow configuration, possibly hindering cargo discharge or vesicle recycling. Next, I discuss how ketamine affects astrocyte capacity to control extracellular K+ by reducing vesicular delivery of the inward rectifying potassium channel (Kir4.1) to the plasmalemma that reduces the surface density of Kir4.1. Modified astroglial K+ buffering impacts upon neuronal firing pattern as demonstrated in lateral habenula in a rat model of depression. Finally, I highlight the discovery that ketamine rapidly redistributes cholesterol in the astrocyte plasmalemma, which may alter the flux of cholesterol to neurons. This structural modification may further modulate a host of processes that synergistically contribute to ketamine’s rapid antidepressant action.
Collapse
|
15
|
Weaver CD, Denton JS. Next-generation inward rectifier potassium channel modulators: discovery and molecular pharmacology. Am J Physiol Cell Physiol 2021; 320:C1125-C1140. [PMID: 33826405 DOI: 10.1152/ajpcell.00548.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Inward rectifying potassium (Kir) channels play important roles in both excitable and nonexcitable cells of various organ systems and could represent valuable new drug targets for cardiovascular, metabolic, immune, and neurological diseases. In nonexcitable epithelial cells of the kidney tubule, for example, Kir1.1 (KCNJ1) and Kir4.1 (KCNJ10) are linked to sodium reabsorption in the thick ascending limb of Henle's loop and distal convoluted tubule, respectively, and have been explored as novel-mechanism diuretic targets for managing hypertension and edema. G protein-coupled Kir channels (Kir3) channels expressed in the central nervous system are critical effectors of numerous signal transduction pathways underlying analgesia, addiction, and respiratory-depressive effects of opioids. The historical dearth of pharmacological tool compounds for exploring the therapeutic potential of Kir channels has led to a molecular target-based approach using high-throughput screen (HTS) of small-molecule libraries and medicinal chemistry to develop "next-generation" Kir channel modulators that are both potent and specific for their targets. In this article, we review recent efforts focused specifically on discovery and improvement of target-selective molecular probes. The reader is introduced to fluorescence-based thallium flux assays that have enabled much of this work and then provided with an overview of progress made toward developing modulators of Kir1.1 (VU590, VU591), Kir2.x (ML133), Kir3.X (ML297, GAT1508, GiGA1, VU059331), Kir4.1 (VU0134992), and Kir7.1 (ML418). We discuss what is known about the small molecules' molecular mechanisms of action, in vitro and in vivo pharmacology, and then close with our view of what critical work remains to be done.
Collapse
Affiliation(s)
- C David Weaver
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee.,Department of Chemistry, Vanderbilt University, Nashville, Tennessee.,Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee
| | - Jerod S Denton
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee.,Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee.,Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee
| |
Collapse
|
16
|
Kinboshi M, Ikeda A, Ohno Y. Role of Astrocytic Inwardly Rectifying Potassium (Kir) 4.1 Channels in Epileptogenesis. Front Neurol 2020; 11:626658. [PMID: 33424762 PMCID: PMC7786246 DOI: 10.3389/fneur.2020.626658] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 12/08/2020] [Indexed: 12/25/2022] Open
Abstract
Astrocytes regulate potassium and glutamate homeostasis via inwardly rectifying potassium (Kir) 4.1 channels in synapses, maintaining normal neural excitability. Numerous studies have shown that dysfunction of astrocytic Kir4.1 channels is involved in epileptogenesis in humans and animal models of epilepsy. Specifically, Kir4.1 channel inhibition by KCNJ10 gene mutation or expressional down-regulation increases the extracellular levels of potassium ions and glutamate in synapses and causes hyperexcitation of neurons. Moreover, recent investigations demonstrated that inhibition of Kir4.1 channels facilitates the expression of brain-derived neurotrophic factor (BDNF), an important modulator of epileptogenesis, in astrocytes. In this review, we summarize the current understanding on the role of astrocytic Kir4.1 channels in epileptogenesis, with a focus on functional and expressional changes in Kir4.1 channels and their regulation of BDNF secretion. We also discuss the potential of Kir4.1 channels as a therapeutic target for the prevention of epilepsy.
Collapse
Affiliation(s)
- Masato Kinboshi
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan.,Department of Epilepsy, Movement Disorders and Physiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Akio Ikeda
- Department of Epilepsy, Movement Disorders and Physiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yukihiro Ohno
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
| |
Collapse
|
17
|
Smith KE, Murphy P, Jagger DJ. Divergent membrane properties of mouse cochlear glial cells around hearing onset. J Neurosci Res 2020; 99:679-698. [PMID: 33099767 DOI: 10.1002/jnr.24744] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 09/21/2020] [Accepted: 10/05/2020] [Indexed: 11/11/2022]
Abstract
Spiral ganglion neurons (SGNs) are the primary afferent neurons of the auditory system, and together with their attendant glia, form the auditory nerve. Within the cochlea, satellite glial cells (SGCs) encapsulate the cell body of SGNs, whereas Schwann cells (SCs) wrap their peripherally- and centrally-directed neurites. Despite their likely importance in auditory nerve function and homeostasis, the physiological properties of auditory glial cells have evaded description. Here, we characterized the voltage-activated membrane currents of glial cells from the mouse cochlea. We identified a prominent weak inwardly rectifying current in SGCs within cochlear slice preparations (postnatal day P5-P6), which was also present in presumptive SGCs within dissociated cultures prepared from the cochleae of hearing mice (P14-P15). Pharmacological block by Ba2+ and desipramine suggested that channels belonging to the Kir4 family mediated the weak inwardly rectifying current, and post hoc immunofluorescence implicated the involvement of Kir4.1 subunits. Additional electrophysiological profiles were identified for glial cells within dissociated cultures, suggesting that glial subtypes may have specific membrane properties to support distinct physiological roles. Immunofluorescence using fixed cochlear sections revealed that although Kir4.1 is restricted to SGCs after the onset of hearing, these channels are more widely distributed within the glial population earlier in postnatal development (i.e., within both SGCs and SCs). The decrease in Kir4.1 immunofluorescence during SC maturation was coincident with a reduction of Sox2 expression and advancing neurite myelination. The data suggest a diversification of glial properties occurs in preparation for sound-driven activity in the auditory nerve.
Collapse
Affiliation(s)
- Katie E Smith
- UCL Ear Institute, University College London, London, UK
| | - Phoebe Murphy
- UCL Ear Institute, University College London, London, UK
| | | |
Collapse
|
18
|
Effect of Nortriptyline on Spreading Depolarization. ARCHIVES OF NEUROSCIENCE 2020. [DOI: 10.5812/ans.102102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background: Spreading depolarization is associated with the extension of lesion size and complications in some important neurological diseases such as stroke, epilepsy, migraine, and traumatic brain injury. Objectives: This study aimed to reveal some molecular aspects of spreading depolarization and suggesting new therapeutic targets for its control by changing the function of different astrocytic and neuronal ion channels. Methods: The effects of nortriptyline on spreading depolarization in cortical and hippocampal tissues and on the electrophysiological properties of CA1 hippocampal pyramidal neurons were assessed by extra- and intracellular recording, following washing rat brain slices by the drug. Results: Nortriptyline made a significant increase in the amplitude of spreading depolarization in cortical and hippocampal tissues relative to control but did not change the duration significantly in each of the tissues. No significant difference was found in the effects of spreading depolarization on the electrophysiological properties of the CA1 pyramidal neurons between nortriptyline and control groups. Conclusions: The stimulating effect of nortriptyline on spreading depolarization is probably related to the augmentation of extracellular potassium collection in the cortex and hippocampus due to inhibition of astrocytic potassium scavenging function. This change can make more neurons prone to depolarization and increase the overall amplitude of spreading depolarization waves. Further studies should assess the effect of enhancing the clearance function of astrocyte-specific inwardly rectifying potassium channels, Kir4.1, or preventing other factors contributing to spreading depolarization on control of the process.
Collapse
|
19
|
Smith KE, Whitcroft K, Law S, Andrews P, Choi D, Jagger DJ. Olfactory ensheathing cells from the nasal mucosa and olfactory bulb have distinct membrane properties. J Neurosci Res 2019; 98:888-901. [PMID: 31797433 DOI: 10.1002/jnr.24566] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/14/2019] [Accepted: 11/14/2019] [Indexed: 12/15/2022]
Abstract
Transplantation of olfactory ensheathing cells (OECs) is a potential therapy for the regeneration of damaged neurons. While they maintain tissue homeostasis in the olfactory mucosa (OM) and olfactory bulb (OB), their regenerative properties also support the normal sense of smell by enabling continual turnover and axonal regrowth of olfactory sensory neurons (OSNs). However, the molecular physiology of OECs is not fully understood, especially that of OECs from the mucosa. Here, we carried out whole-cell patch-clamp recordings from individual OECs cultured from the OM and OB of the adult rat, and from the human OM. A subset of OECs from the rat OM cultured 1-3 days in vitro had large weakly rectifying K+ currents, which were sensitive to Ba2+ and desipramine, blockers of Kir4-family channels. Kir4.1 immunofluorescence was detectable in cultured OM cells colabeled for the OEC marker S100, and in S100-labeled cells found adjacent to OSN axons in mucosal sections. OECs cultured from rat OB had distinct properties though, displaying strongly rectifying inward currents at hyperpolarized membrane potentials and strongly rectifying outward currents at depolarized potentials. Kir4.1 immunofluorescence was not evident in OECs adjacent to axons of OSNs in the OB. A subset of human OECs cultured from the OM of adults had membrane properties comparable to those of the rat OM that is dominated by Ba2+ -sensitive weak inwardly rectifying currents. The membrane properties of peripheral OECs are different to those of central OECs, suggesting they may play distinct roles during olfaction.
Collapse
Affiliation(s)
- Katie E Smith
- UCL Ear Institute, University College London, London, UK
| | - Katherine Whitcroft
- UCL Ear Institute, University College London, London, UK.,Royal National Throat Nose & Ear Hospital, London, UK
| | - Stuart Law
- Institute of Neurology, University College London, London, UK
| | - Peter Andrews
- UCL Ear Institute, University College London, London, UK.,Royal National Throat Nose & Ear Hospital, London, UK
| | - David Choi
- Institute of Neurology, University College London, London, UK
| | | |
Collapse
|
20
|
Xiong Z, Zhang K, Ren Q, Chang L, Chen J, Hashimoto K. Increased expression of inwardly rectifying Kir4.1 channel in the parietal cortex from patients with major depressive disorder. J Affect Disord 2019; 245:265-269. [PMID: 30419525 DOI: 10.1016/j.jad.2018.11.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 09/22/2018] [Accepted: 11/03/2018] [Indexed: 12/25/2022]
Abstract
BACKGROUND The inwardly rectifying K+ channel subtype Kir4.1 has been well studied in the astrocyte within brain; however, the precise role of this protein in psychiatric disorders is unknown. Kir4.1 is also known to interact with GABAB receptors which may be implicated in psychiatric disorders. Here we studied whether expression of Kir4.1 and GABAB receptors was altered in the postmortem brain samples (parietal cortex and cerebellum) from patients with major psychiatric disorders. METHODS Protein expression of Kir4.1 and GABAB receptors in the parietal cortex and cerebellum from control, major depressive disorder (MDD), schizophrenia (SZ), and bipolar disorder (BD) groups was measured. RESULTS Levels of Kir4.1 in the parietal cortex from MDD group, but not SZ and BD groups, were significantly higher than the control group. Furthermore, levels of GABAB receptor subunit 1 in the parietal cortex from MDD group and SZ group, but not BD group, were also significantly higher than the control group. Interestingly, there was a positive correlation between Kir4.1 protein and GABAB receptor subunit 1 in the parietal cortex from control group, but not MDD group. LIMITATIONS The small number in each group may limit our interpretation. Only two brain regions were analyzed. CONCLUSIONS Abnormalities in the interaction of Kir4.1 and GABAB receptor in the parietal cortex might play a role in the pathophysiology of MDD.
Collapse
Affiliation(s)
- Zhongwei Xiong
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, Chiba 260-8670, Japan; Department of Neurosurgery, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan 430071, PR China
| | - Kai Zhang
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, Chiba 260-8670, Japan
| | - Qian Ren
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, Chiba 260-8670, Japan
| | - Lijia Chang
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, Chiba 260-8670, Japan
| | - Jincao Chen
- Department of Neurosurgery, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan 430071, PR China
| | - Kenji Hashimoto
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, Chiba 260-8670, Japan.
| |
Collapse
|
21
|
Ohno Y, Kinboshi M, Shimizu S. Inwardly Rectifying Potassium Channel Kir4.1 as a Novel Modulator of BDNF Expression in Astrocytes. Int J Mol Sci 2018; 19:ijms19113313. [PMID: 30356026 PMCID: PMC6274740 DOI: 10.3390/ijms19113313] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 10/19/2018] [Accepted: 10/22/2018] [Indexed: 12/02/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) is a key molecule essential for neural plasticity and development, and is implicated in the pathophysiology of various central nervous system (CNS) disorders. It is now documented that BDNF is synthesized not only in neurons, but also in astrocytes which actively regulate neuronal activities by forming tripartite synapses. Inwardly rectifying potassium (Kir) channel subunit Kir4.1, which is specifically expressed in astrocytes, constructs Kir4.1 and Kir4.1/5.1 channels, and mediates the spatial potassium (K+) buffering action of astrocytes. Recent evidence illustrates that Kir4.1 channels play important roles in bringing about the actions of antidepressant drugs and modulating BDNF expression in astrocytes. Although the precise mechanisms remain to be clarified, it seems likely that inhibition (down-regulation or blockade) of astrocytic Kir4.1 channels attenuates K+ buffering, increases neuronal excitability by elevating extracellular K+ and glutamate, and facilitates BDNF expression. Conversely, activation (up-regulation or opening) of Kir4.1 channels reduces neuronal excitability by lowering extracellular K+ and glutamate, and attenuates BDNF expression. Particularly, the former pathophysiological alterations seem to be important in epileptogenesis and pain sensitization, and the latter in the pathogenesis of depressive disorders. In this article, we review the functions of Kir4.1 channels, with a focus on their regulation of spatial K+ buffering and BDNF expression in astrocytes, and discuss the role of the astrocytic Kir4.1-BDNF system in modulating CNS disorders.
Collapse
Affiliation(s)
- Yukihiro Ohno
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.
| | - Masato Kinboshi
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.
| | - Saki Shimizu
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.
| |
Collapse
|
22
|
Kharade SV, Kurata H, Bender AM, Blobaum AL, Figueroa EE, Duran A, Kramer M, Days E, Vinson P, Flores D, Satlin LM, Meiler J, Weaver CD, Lindsley CW, Hopkins CR, Denton JS. Discovery, Characterization, and Effects on Renal Fluid and Electrolyte Excretion of the Kir4.1 Potassium Channel Pore Blocker, VU0134992. Mol Pharmacol 2018; 94:926-937. [PMID: 29895592 DOI: 10.1124/mol.118.112359] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 05/30/2018] [Indexed: 12/28/2022] Open
Abstract
The inward rectifier potassium (Kir) channel Kir4.1 (KCNJ10) carries out important physiologic roles in epithelial cells of the kidney, astrocytes in the central nervous system, and stria vascularis of the inner ear. Loss-of-function mutations in KCNJ10 lead to EAST/SeSAME syndrome, which is characterized by epilepsy, ataxia, renal salt wasting, and sensorineural deafness. Although genetic approaches have been indispensable for establishing the importance of Kir4.1 in the normal function of these tissues, the availability of pharmacological tools for acutely manipulating the activity of Kir4.1 in genetically normal animals has been lacking. We therefore carried out a high-throughput screen of 76,575 compounds from the Vanderbilt Institute of Chemical Biology library for small-molecule modulators of Kir4.1. The most potent inhibitor identified was 2-(2-bromo-4-isopropylphenoxy)-N-(2,2,6,6-tetramethylpiperidin-4-yl)acetamide (VU0134992). In whole-cell patch-clamp electrophysiology experiments, VU0134992 inhibits Kir4.1 with an IC50 value of 0.97 µM and is 9-fold selective for homomeric Kir4.1 over Kir4.1/5.1 concatemeric channels (IC50 = 9 µM) at -120 mV. In thallium (Tl+) flux assays, VU0134992 is greater than 30-fold selective for Kir4.1 over Kir1.1, Kir2.1, and Kir2.2; is weakly active toward Kir2.3, Kir6.2/SUR1, and Kir7.1; and is equally active toward Kir3.1/3.2, Kir3.1/3.4, and Kir4.2. This potency and selectivity profile is superior to Kir4.1 inhibitors amitriptyline, nortriptyline, and fluoxetine. Medicinal chemistry identified components of VU0134992 that are critical for inhibiting Kir4.1. Patch-clamp electrophysiology, molecular modeling, and site-directed mutagenesis identified pore-lining glutamate 158 and isoleucine 159 as critical residues for block of the channel. VU0134992 displayed a large free unbound fraction (fu) in rat plasma (fu = 0.213). Consistent with the known role of Kir4.1 in renal function, oral dosing of VU0134992 led to a dose-dependent diuresis, natriuresis, and kaliuresis in rats. Thus, VU0134992 represents the first in vivo active tool compound for probing the therapeutic potential of Kir4.1 as a novel diuretic target for the treatment of hypertension.
Collapse
Affiliation(s)
- Sujay V Kharade
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee (S.V.K., M.K., J.S.D.); Center for Neuroscience Drug Discovery and the Vanderbilt Specialized Chemistry Center for Accelerated Probe Development (H.K., A.M.B., A.L.B., C.W.L., C.R.H.), Departments of Pharmacology (H.K., A.M.B., E.E.F., J.M., C.D.W., C.W.L., J.S.D.) and Chemistry (A.D., J.M., C.D.W., C.W.L.), High-Throughput Screening Center (E.D., P.V.), and Institute of Chemical Biology (C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York (D.F., L.M.S.); and Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska (C.R.H.)
| | - Haruto Kurata
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee (S.V.K., M.K., J.S.D.); Center for Neuroscience Drug Discovery and the Vanderbilt Specialized Chemistry Center for Accelerated Probe Development (H.K., A.M.B., A.L.B., C.W.L., C.R.H.), Departments of Pharmacology (H.K., A.M.B., E.E.F., J.M., C.D.W., C.W.L., J.S.D.) and Chemistry (A.D., J.M., C.D.W., C.W.L.), High-Throughput Screening Center (E.D., P.V.), and Institute of Chemical Biology (C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York (D.F., L.M.S.); and Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska (C.R.H.)
| | - Aaron M Bender
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee (S.V.K., M.K., J.S.D.); Center for Neuroscience Drug Discovery and the Vanderbilt Specialized Chemistry Center for Accelerated Probe Development (H.K., A.M.B., A.L.B., C.W.L., C.R.H.), Departments of Pharmacology (H.K., A.M.B., E.E.F., J.M., C.D.W., C.W.L., J.S.D.) and Chemistry (A.D., J.M., C.D.W., C.W.L.), High-Throughput Screening Center (E.D., P.V.), and Institute of Chemical Biology (C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York (D.F., L.M.S.); and Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska (C.R.H.)
| | - Anna L Blobaum
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee (S.V.K., M.K., J.S.D.); Center for Neuroscience Drug Discovery and the Vanderbilt Specialized Chemistry Center for Accelerated Probe Development (H.K., A.M.B., A.L.B., C.W.L., C.R.H.), Departments of Pharmacology (H.K., A.M.B., E.E.F., J.M., C.D.W., C.W.L., J.S.D.) and Chemistry (A.D., J.M., C.D.W., C.W.L.), High-Throughput Screening Center (E.D., P.V.), and Institute of Chemical Biology (C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York (D.F., L.M.S.); and Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska (C.R.H.)
| | - Eric E Figueroa
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee (S.V.K., M.K., J.S.D.); Center for Neuroscience Drug Discovery and the Vanderbilt Specialized Chemistry Center for Accelerated Probe Development (H.K., A.M.B., A.L.B., C.W.L., C.R.H.), Departments of Pharmacology (H.K., A.M.B., E.E.F., J.M., C.D.W., C.W.L., J.S.D.) and Chemistry (A.D., J.M., C.D.W., C.W.L.), High-Throughput Screening Center (E.D., P.V.), and Institute of Chemical Biology (C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York (D.F., L.M.S.); and Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska (C.R.H.)
| | - Amanda Duran
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee (S.V.K., M.K., J.S.D.); Center for Neuroscience Drug Discovery and the Vanderbilt Specialized Chemistry Center for Accelerated Probe Development (H.K., A.M.B., A.L.B., C.W.L., C.R.H.), Departments of Pharmacology (H.K., A.M.B., E.E.F., J.M., C.D.W., C.W.L., J.S.D.) and Chemistry (A.D., J.M., C.D.W., C.W.L.), High-Throughput Screening Center (E.D., P.V.), and Institute of Chemical Biology (C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York (D.F., L.M.S.); and Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska (C.R.H.)
| | - Meghan Kramer
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee (S.V.K., M.K., J.S.D.); Center for Neuroscience Drug Discovery and the Vanderbilt Specialized Chemistry Center for Accelerated Probe Development (H.K., A.M.B., A.L.B., C.W.L., C.R.H.), Departments of Pharmacology (H.K., A.M.B., E.E.F., J.M., C.D.W., C.W.L., J.S.D.) and Chemistry (A.D., J.M., C.D.W., C.W.L.), High-Throughput Screening Center (E.D., P.V.), and Institute of Chemical Biology (C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York (D.F., L.M.S.); and Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska (C.R.H.)
| | - Emily Days
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee (S.V.K., M.K., J.S.D.); Center for Neuroscience Drug Discovery and the Vanderbilt Specialized Chemistry Center for Accelerated Probe Development (H.K., A.M.B., A.L.B., C.W.L., C.R.H.), Departments of Pharmacology (H.K., A.M.B., E.E.F., J.M., C.D.W., C.W.L., J.S.D.) and Chemistry (A.D., J.M., C.D.W., C.W.L.), High-Throughput Screening Center (E.D., P.V.), and Institute of Chemical Biology (C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York (D.F., L.M.S.); and Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska (C.R.H.)
| | - Paige Vinson
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee (S.V.K., M.K., J.S.D.); Center for Neuroscience Drug Discovery and the Vanderbilt Specialized Chemistry Center for Accelerated Probe Development (H.K., A.M.B., A.L.B., C.W.L., C.R.H.), Departments of Pharmacology (H.K., A.M.B., E.E.F., J.M., C.D.W., C.W.L., J.S.D.) and Chemistry (A.D., J.M., C.D.W., C.W.L.), High-Throughput Screening Center (E.D., P.V.), and Institute of Chemical Biology (C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York (D.F., L.M.S.); and Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska (C.R.H.)
| | - Daniel Flores
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee (S.V.K., M.K., J.S.D.); Center for Neuroscience Drug Discovery and the Vanderbilt Specialized Chemistry Center for Accelerated Probe Development (H.K., A.M.B., A.L.B., C.W.L., C.R.H.), Departments of Pharmacology (H.K., A.M.B., E.E.F., J.M., C.D.W., C.W.L., J.S.D.) and Chemistry (A.D., J.M., C.D.W., C.W.L.), High-Throughput Screening Center (E.D., P.V.), and Institute of Chemical Biology (C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York (D.F., L.M.S.); and Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska (C.R.H.)
| | - Lisa M Satlin
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee (S.V.K., M.K., J.S.D.); Center for Neuroscience Drug Discovery and the Vanderbilt Specialized Chemistry Center for Accelerated Probe Development (H.K., A.M.B., A.L.B., C.W.L., C.R.H.), Departments of Pharmacology (H.K., A.M.B., E.E.F., J.M., C.D.W., C.W.L., J.S.D.) and Chemistry (A.D., J.M., C.D.W., C.W.L.), High-Throughput Screening Center (E.D., P.V.), and Institute of Chemical Biology (C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York (D.F., L.M.S.); and Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska (C.R.H.)
| | - Jens Meiler
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee (S.V.K., M.K., J.S.D.); Center for Neuroscience Drug Discovery and the Vanderbilt Specialized Chemistry Center for Accelerated Probe Development (H.K., A.M.B., A.L.B., C.W.L., C.R.H.), Departments of Pharmacology (H.K., A.M.B., E.E.F., J.M., C.D.W., C.W.L., J.S.D.) and Chemistry (A.D., J.M., C.D.W., C.W.L.), High-Throughput Screening Center (E.D., P.V.), and Institute of Chemical Biology (C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York (D.F., L.M.S.); and Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska (C.R.H.)
| | - C David Weaver
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee (S.V.K., M.K., J.S.D.); Center for Neuroscience Drug Discovery and the Vanderbilt Specialized Chemistry Center for Accelerated Probe Development (H.K., A.M.B., A.L.B., C.W.L., C.R.H.), Departments of Pharmacology (H.K., A.M.B., E.E.F., J.M., C.D.W., C.W.L., J.S.D.) and Chemistry (A.D., J.M., C.D.W., C.W.L.), High-Throughput Screening Center (E.D., P.V.), and Institute of Chemical Biology (C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York (D.F., L.M.S.); and Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska (C.R.H.)
| | - Craig W Lindsley
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee (S.V.K., M.K., J.S.D.); Center for Neuroscience Drug Discovery and the Vanderbilt Specialized Chemistry Center for Accelerated Probe Development (H.K., A.M.B., A.L.B., C.W.L., C.R.H.), Departments of Pharmacology (H.K., A.M.B., E.E.F., J.M., C.D.W., C.W.L., J.S.D.) and Chemistry (A.D., J.M., C.D.W., C.W.L.), High-Throughput Screening Center (E.D., P.V.), and Institute of Chemical Biology (C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York (D.F., L.M.S.); and Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska (C.R.H.)
| | - Corey R Hopkins
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee (S.V.K., M.K., J.S.D.); Center for Neuroscience Drug Discovery and the Vanderbilt Specialized Chemistry Center for Accelerated Probe Development (H.K., A.M.B., A.L.B., C.W.L., C.R.H.), Departments of Pharmacology (H.K., A.M.B., E.E.F., J.M., C.D.W., C.W.L., J.S.D.) and Chemistry (A.D., J.M., C.D.W., C.W.L.), High-Throughput Screening Center (E.D., P.V.), and Institute of Chemical Biology (C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York (D.F., L.M.S.); and Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska (C.R.H.)
| | - Jerod S Denton
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee (S.V.K., M.K., J.S.D.); Center for Neuroscience Drug Discovery and the Vanderbilt Specialized Chemistry Center for Accelerated Probe Development (H.K., A.M.B., A.L.B., C.W.L., C.R.H.), Departments of Pharmacology (H.K., A.M.B., E.E.F., J.M., C.D.W., C.W.L., J.S.D.) and Chemistry (A.D., J.M., C.D.W., C.W.L.), High-Throughput Screening Center (E.D., P.V.), and Institute of Chemical Biology (C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York (D.F., L.M.S.); and Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska (C.R.H.)
| |
Collapse
|
23
|
Kinoshita M, Hirayama Y, Fujishita K, Shibata K, Shinozaki Y, Shigetomi E, Takeda A, Le HPN, Hayashi H, Hiasa M, Moriyama Y, Ikenaka K, Tanaka KF, Koizumi S. Anti-Depressant Fluoxetine Reveals its Therapeutic Effect Via Astrocytes. EBioMedicine 2018; 32:72-83. [PMID: 29887330 PMCID: PMC6020856 DOI: 10.1016/j.ebiom.2018.05.036] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 05/17/2018] [Accepted: 05/30/2018] [Indexed: 01/08/2023] Open
Abstract
Although psychotropic drugs act on neurons and glial cells, how glia respond, and whether glial responses are involved in therapeutic effects are poorly understood. Here, we show that fluoxetine (FLX), an anti-depressant, mediates its anti-depressive effect by increasing the gliotransmission of ATP. FLX increased ATP exocytosis via vesicular nucleotide transporter (VNUT). FLX-induced anti-depressive behavior was decreased in astrocyte-selective VNUT-knockout mice or when VNUT was deleted in mice, but it was increased when astrocyte-selective VNUT was overexpressed in mice. This suggests that VNUT-dependent astrocytic ATP exocytosis has a critical role in the therapeutic effect of FLX. Released ATP and its metabolite adenosine act on P2Y11 and adenosine A2b receptors expressed by astrocytes, causing an increase in brain-derived neurotrophic factor in astrocytes. These findings suggest that in addition to neurons, FLX acts on astrocytes and mediates its therapeutic effects by increasing ATP gliotransmission. Anti-depressant FLX acts on astrocytes and increases VNUT-dependent ATP exocytosis. Such astrocytic responses are responsible for the FLX-induced therapeutic effects. Astrocytic ATP and its metabolite adenosine increase BDNF in astrocytes, and reveal the therapeutic effects.
Kinoshita et al. demonstrated that astrocytes are a therapeutic target of the antidepressant, fluoxetine (FLX). They found that FLX stimulates VNUT-dependent ATP release from astrocytes leading to a BDNF-mediated anti-depressive effect. This study demonstrated the astrocytic regulation of this anti-depressive effect, which complements the previously described conventional mechanism of FLX. Because the involvement of astrocytes in the pathogenesis of depression is of current interest, this new insight into the role of astrocytes in anti-depressive effects should support the establishment of novel therapeutic strategies for depression.
Collapse
Affiliation(s)
- Manao Kinoshita
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi 409-3898, Japan
| | - Yuri Hirayama
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi 409-3898, Japan
| | - Kayoko Fujishita
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi 409-3898, Japan
| | - Keisuke Shibata
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi 409-3898, Japan
| | - Youichi Shinozaki
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi 409-3898, Japan
| | - Eiji Shigetomi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi 409-3898, Japan
| | - Akiko Takeda
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi 409-3898, Japan
| | - Ha Pham Ngoc Le
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi 409-3898, Japan
| | - Hideaki Hayashi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi 409-3898, Japan
| | - Miki Hiasa
- Department of Membrane Biochemistry, Okayama University, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Yoshinori Moriyama
- Department of Membrane Biochemistry, Okayama University, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan; Department of Biochemistry, Matsumoto Dental University, Shiojiri 399-0781, Japan
| | - Kazuhiro Ikenaka
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki 444-8585, Japan
| | - Kenji F Tanaka
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi 409-3898, Japan.
| |
Collapse
|
24
|
Ohno Y. Astrocytic Kir4.1 potassium channels as a novel therapeutic target for epilepsy and mood disorders. Neural Regen Res 2018; 13:651-652. [PMID: 29722316 PMCID: PMC5950674 DOI: 10.4103/1673-5374.230355] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Affiliation(s)
- Yukihiro Ohno
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Osaka, Japan
| |
Collapse
|
25
|
Kinboshi M, Mukai T, Nagao Y, Matsuba Y, Tsuji Y, Tanaka S, Tokudome K, Shimizu S, Ito H, Ikeda A, Inanobe A, Kurachi Y, Inoue S, Ohno Y. Inhibition of Inwardly Rectifying Potassium (Kir) 4.1 Channels Facilitates Brain-Derived Neurotrophic Factor (BDNF) Expression in Astrocytes. Front Mol Neurosci 2017; 10:408. [PMID: 29358904 PMCID: PMC5768989 DOI: 10.3389/fnmol.2017.00408] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 11/24/2017] [Indexed: 11/16/2022] Open
Abstract
Inwardly rectifying potassium (Kir) 4.1 channels in astrocytes regulate neuronal excitability by mediating spatial potassium buffering. Although dysfunction of astrocytic Kir4.1 channels is implicated in the development of epileptic seizures, the functional mechanisms of Kir4.1 channels in modulating epileptogenesis remain unknown. We herein evaluated the effects of Kir4.1 inhibition (blockade and knockdown) on expression of brain-derived neurotrophic factor (BDNF), a key modulator of epileptogenesis, in the primary cultures of mouse astrocytes. For blockade of Kir4.1 channels, we tested several antidepressant agents which reportedly bound to and blocked Kir4.1 channels in a subunit-specific manner. Treatment of astrocytes with fluoxetine enhanced BDNF mRNA expression in a concentration-dependent manner and increased the BDNF protein level. Other antidepressants (e.g., sertraline and imipramine) also increased the expression of BDNF mRNA with relative potencies similar to those for inhibition of Kir4.1 channels. In addition, suppression of Kir4.1 expression by the transfection of small interfering RNA (siRNA) targeting Kir4.1 significantly increased the mRNA and protein levels of BDNF. The BDNF induction by Kir4.1 siRNA transfection was suppressed by the MEK1/2 inhibitor U0126, but not by the p38 MAPK inhibitor SB202190 or the JNK inhibitor SP600125. The present results demonstrated that inhibition of Kir4.1 channels facilitates BDNF expression in astrocytes primarily by activating the Ras/Raf/MEK/ERK pathway, which may be linked to the development of epilepsy and other neuropsychiatric disorders.
Collapse
Affiliation(s)
- Masato Kinboshi
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Osaka, Japan.,Department of Neurology, Wakayama Medical University, Wakayama, Japan.,Department of Epilepsy, Movement Disorders and Physiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takahiro Mukai
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Osaka, Japan
| | - Yuki Nagao
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Osaka, Japan
| | - Yusuke Matsuba
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Osaka, Japan
| | - Yoshimi Tsuji
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Osaka, Japan
| | - Shiho Tanaka
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Osaka, Japan
| | - Kentaro Tokudome
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Osaka, Japan.,Department of Molecular and Cellular Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Saki Shimizu
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Osaka, Japan
| | - Hidefumi Ito
- Department of Neurology, Wakayama Medical University, Wakayama, Japan
| | - Akio Ikeda
- Department of Epilepsy, Movement Disorders and Physiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Atsushi Inanobe
- Department of Molecular and Cellular Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Yoshihisa Kurachi
- Department of Molecular and Cellular Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Seiji Inoue
- Education and Research Center for Fundamental Pharmaceutical Sciences, Osaka University of Pharmaceutical Sciences, Osaka, Japan
| | - Yukihiro Ohno
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Osaka, Japan
| |
Collapse
|
26
|
Tomilin VN, Zaika O, Subramanya AR, Pochynyuk O. Dietary K + and Cl - independently regulate basolateral conductance in principal and intercalated cells of the collecting duct. Pflugers Arch 2017; 470:339-353. [PMID: 29134279 DOI: 10.1007/s00424-017-2084-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 10/17/2017] [Accepted: 10/24/2017] [Indexed: 02/07/2023]
Abstract
The renal collecting duct contains two distinct cell types, principal and intercalated cells, expressing potassium Kir4.1/5.1 (KCNJ10/16) and chloride ClC-K2 (ClC-Kb in humans) channels on their basolateral membrane, respectively. Both channels are thought to play important roles in controlling systemic water-electrolyte balance and blood pressure. However, little is known about mechanisms regulating activity of Kir4.1/5.1 and ClC-K2/b. Here, we employed patch clamp analysis at the single channel and whole cell levels in freshly isolated mouse collecting ducts to investigate regulation of Kir4.1/5.1 and ClC-K2/b by dietary K+ and Cl- intake. Treatment of mice with high K+ and high Cl- diet (6% K+, 5% Cl-) for 1 week significantly increased basolateral K+-selective current, single channel Kir4.1/5.1 activity and induced hyperpolarization of basolateral membrane potential in principal cells when compared to values in mice on a regular diet (0.9% K+, 0.5% Cl-). In contrast, basolateral Cl--selective current and single channel ClC-K2/b activity was markedly decreased in intercalated cells under this condition. Substitution of dietary K+ to Na+ in the presence of high Cl- exerted a similar inhibiting action of ClC-K2/b suggesting that the channel is sensitive to variations in dietary Cl- per se. Cl--sensitive with-no-lysine kinase (WNK) cascade has been recently proposed to orchestrate electrolyte transport in the distal tubule during variations of dietary K+. However, co-expression of WNK1 or its major downstream effector Ste20-related proline-alanine-rich kinase (SPAK) had no effect on ClC-Kb over-expressed in Chinese hamster ovary (CHO) cells. Treatment of mice with high K+ diet without concomitant elevations in dietary Cl- (6% K+, 0.5% Cl-) elicited a comparable increase in basolateral K+-selective current, single channel Kir4.1/5.1 activity in principal cells, but had no significant effect on ClC-K2/b activity in intercalated cells. Furthermore, stimulation of aldosterone signaling by Deoxycorticosterone acetate (DOCA) recapitulated the stimulatory actions of high K+ intake on Kir4.1/5.1 channels in principal cells but was ineffective to alter ClC-K2/b activity and basolateral Cl- conductance in intercalated cells. In summary, we report that variations of dietary K+ and Cl- independently regulate basolateral potassium and chloride conductance in principal and intercalated cells. We propose that such discrete mechanism might contribute to fine-tuning of urinary excretion of electrolytes depending on dietary intake.
Collapse
Affiliation(s)
- Viktor N Tomilin
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, 6431 Fannin, Houston, TX, 77030, USA
| | - Oleg Zaika
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, 6431 Fannin, Houston, TX, 77030, USA
| | - Arohan R Subramanya
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
| | - Oleh Pochynyuk
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, 6431 Fannin, Houston, TX, 77030, USA.
| |
Collapse
|
27
|
Aréchiga-Figueroa IA, Marmolejo-Murillo LG, Cui M, Delgado-Ramírez M, van der Heyden MAG, Sánchez-Chapula JA, Rodríguez-Menchaca AA. High-potency block of Kir4.1 channels by pentamidine: Molecular basis. Eur J Pharmacol 2017; 815:56-63. [PMID: 28993158 DOI: 10.1016/j.ejphar.2017.10.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Revised: 10/03/2017] [Accepted: 10/05/2017] [Indexed: 02/06/2023]
Abstract
Inward rectifier potassium (Kir) channels are expressed in almost all mammalian tissues and contribute to a wide range of physiological processes. Kir4.1 channel expression is found in the brain, inner ear, eye, and kidney. Loss-of-function mutations in the pore-forming Kir4.1 subunit cause an autosomal recessive disorder characterized by epilepsy, ataxia, sensorineural deafness and tubulopathy (SeSAME/EST syndrome). Despite its importance in physiological and pathological conditions, pharmacological research of Kir4.1 is limited. Here, we characterized the effect of pentamidine on Kir4.1 channels using electrophysiology, mutagenesis and computational methods. Pentamidine potently inhibited Kir4.1 channels when applied to the cytoplasmic side under inside-out patch clamp configuration (IC50 = 97nM). The block was voltage dependent. Molecular modeling predicted the binding of pentamidine to the transmembrane pore region of Kir4.1 at aminoacids T127, T128 and E158. Mutation of each of these residues reduced the potency of pentamidine to block Kir4.1 channels. A pentamidine analog (PA-6) inhibited Kir4.1 with similar potency (IC50 = 132nM). Overall, this study shows that pentamidine blocks Kir4.1 channels interacting with threonine and glutamate residues in the transmembrane pore region. These results can be useful to design novel compounds with major potency and specificity over Kir4.1 channels.
Collapse
Affiliation(s)
- Iván A Aréchiga-Figueroa
- CONACYT, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP, Mexico
| | | | - Meng Cui
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, USA
| | - Mayra Delgado-Ramírez
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, SLP, Mexico
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - José A Sánchez-Chapula
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Col, Mexico
| | - Aldo A Rodríguez-Menchaca
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, SLP, Mexico.
| |
Collapse
|
28
|
Inhibition of Kir4.1 potassium channels by quinacrine. Brain Res 2017; 1663:87-94. [PMID: 28288868 DOI: 10.1016/j.brainres.2017.03.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 02/24/2017] [Accepted: 03/07/2017] [Indexed: 12/27/2022]
Abstract
Inwardly rectifying potassium (Kir) channels are expressed in many cell types and contribute to a wide range of physiological processes. Particularly, Kir4.1 channels are involved in the astroglial spatial potassium buffering. In this work, we examined the effects of the cationic amphiphilic drug quinacrine on Kir4.1 channels heterologously expressed in HEK293 cells, employing the patch clamp technique. Quinacrine inhibited the currents of Kir4.1 channels in a concentration and voltage dependent manner. In inside-out patches, quinacrine inhibited Kir4.1 channels with an IC50 value of 1.8±0.3μM and with extremely slow blocking and unblocking kinetics. Molecular modeling combined with mutagenesis studies suggested that quinacrine blocks Kir4.1 by plugging the central cavity of the channels, stabilized by the residues E158 and T128. Overall, this study shows that quinacrine blocks Kir4.1 channels, which would be expected to impact the potassium transport in several tissues.
Collapse
|
29
|
Shin SE, Li H, Kim HS, Kim HW, Seo MS, Ha KS, Han ET, Hong SH, Firth AL, Choi IW, Bae YM, Park WS. Nortriptyline, a tricyclic antidepressant, inhibits voltage-dependent K + channels in coronary arterial smooth muscle cells. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2017; 21:225-232. [PMID: 28280416 PMCID: PMC5343056 DOI: 10.4196/kjpp.2017.21.2.225] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 12/07/2016] [Accepted: 12/07/2016] [Indexed: 11/30/2022]
Abstract
We demonstrated the effect of nortriptyline, a tricyclic antidepressant drug and serotonin reuptake inhibitor, on voltage-dependent K+ (Kv) channels in freshly isolated rabbit coronary arterial smooth muscle cells using a whole-cell patch clamp technique. Nortriptyline inhibited Kv currents in a concentration-dependent manner, with an apparent IC50 value of 2.86±0.52 µM and a Hill coefficient of 0.77±0.1. Although application of nortriptyline did not change the activation curve, nortriptyline shifted the inactivation current toward a more negative potential. Application of train pulses (1 or 2 Hz) did not change the nortriptyline-induced Kv channel inhibition, suggesting that the effects of nortiprtyline were not use-dependent. Preincubation with the Kv1.5 and Kv2.1/2.2 inhibitors, DPO-1 and guangxitoxin did not affect nortriptyline inhibition of Kv channels. From these results, we concluded that nortriptyline inhibited Kv channels in a concentration-dependent and state-independent manner independently of serotonin reuptake.
Collapse
Affiliation(s)
- Sung Eun Shin
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon 24341, Korea
| | - Hongliang Li
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon 24341, Korea
| | - Han Sol Kim
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon 24341, Korea
| | - Hye Won Kim
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon 24341, Korea
| | - Mi Seon Seo
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon 24341, Korea
| | - Kwon-Soo Ha
- Department of Molecular and Cellular Biochemistry, Kangwon National University School of Medicine, Chuncheon 24341, Korea
| | - Eun-Taek Han
- Department of Medical Environmental Biology and Tropical Medicine, Kangwon National University School of Medicine, Chuncheon 24341, Korea
| | - Seok-Ho Hong
- Department of Internal Medicine, Kangwon National University School of Medicine, Chuncheon 24341, Korea
| | - Amy L Firth
- Department of Pulmonary, Critical Care and Sleep Medicine, University of Southern California, Keck School of Medicine, Los Angeles, CA90033, USA
| | - Il-Whan Choi
- Department of Microbiology, Inje University College of Medicine, Busan 48516, Korea
| | - Young Min Bae
- Department of Physiology, Konkuk University School of Medicine, Chungju 27478, Korea
| | - Won Sun Park
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon 24341, Korea
| |
Collapse
|
30
|
Chloroquine blocks the Kir4.1 channels by an open-pore blocking mechanism. Eur J Pharmacol 2017; 800:40-47. [PMID: 28216048 DOI: 10.1016/j.ejphar.2017.02.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 02/03/2017] [Accepted: 02/15/2017] [Indexed: 11/23/2022]
Abstract
Kir4.1 channels have been implicated in various physiological processes, mainly in the K+ homeostasis of the central nervous system and in the control of glial function and neuronal excitability. Even though, pharmacological research of these channels is very limited. Chloroquine (CQ) is an amino quinolone derivative known to inhibit Kir2.1 and Kir6.2 channels with different action mechanism and binding site. Here, we employed patch-clamp methods, mutagenesis analysis, and molecular modeling to characterize the molecular pharmacology of Kir4.1 inhibition by CQ. We found that this drug inhibits Kir4.1 channels heterologously expressed in HEK-293 cells. CQ produced a fast-onset voltage-dependent pore-blocking effect on these channels. In inside-out patches, CQ showed notable higher potency (IC50 ≈0.5μM at +50mV) and faster onset of block when compared to whole-cell configuration (IC50 ≈7μM at +60mV). Also, CQ showed a voltage-dependent unblock with repolarization. These results suggest that the drug directly blocks Kir4.1 channels by a pore-plugging mechanism. Moreover, we found that two residues (Thr128 and Glu158), facing the central cavity and located within the transmembrane pore, are particularly important structural determinants of CQ block. This evidence was similar to what was previously reported with Kir6.2, but distinct from the interaction site (cytoplasmic pore) CQ-Kir2.1. Thus, our findings highlight the diversity of interaction sites and mechanisms that underlie amino quinolone inhibition of Kir channels.
Collapse
|
31
|
Palygin O, Pochynyuk O, Staruschenko A. Role and mechanisms of regulation of the basolateral K ir 4.1/K ir 5.1K + channels in the distal tubules. Acta Physiol (Oxf) 2017; 219:260-273. [PMID: 27129733 PMCID: PMC5086442 DOI: 10.1111/apha.12703] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 01/28/2016] [Accepted: 04/28/2016] [Indexed: 12/11/2022]
Abstract
Epithelial K+ channels are essential for maintaining electrolyte and fluid homeostasis in the kidney. It is recognized that basolateral inward-rectifying K+ (Kir ) channels play an important role in the control of resting membrane potential and transepithelial voltage, thereby modulating water and electrolyte transport in the distal part of nephron and collecting duct. Monomeric Kir 4.1 (encoded by Kcnj10 gene) and heteromeric Kir 4.1/Kir 5.1 (Kir 4.1 together with Kir 5.1 (Kcnj16)) channels are abundantly expressed at the basolateral membranes of the distal convoluted tubule and the cortical collecting duct cells. Loss-of-function mutations in KCNJ10 cause EAST/SeSAME tubulopathy in humans associated with salt wasting, hypomagnesaemia, metabolic alkalosis and hypokalaemia. In contrast, mice lacking Kir 5.1 have severe renal phenotype that, apart from hypokalaemia, is the opposite of the phenotype seen in EAST/SeSAME syndrome. Experimental advances using genetic animal models provided critical insights into the physiological role of these channels in electrolyte homeostasis and the control of kidney function. Here, we discuss current knowledge about K+ channels at the basolateral membrane of the distal tubules with specific focus on the homomeric Kir 4.1 and heteromeric Kir 4.1/Kir 5.1 channels. Recently identified molecular mechanisms regulating expression and activity of these channels, such as cell acidification, dopamine, insulin and insulin-like growth factor-1, Src family protein tyrosine kinases, as well as the role of these channels in NCC-mediated transport in the distal convoluted tubules, are also described.
Collapse
Affiliation(s)
- Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Oleh Pochynyuk
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | | |
Collapse
|
32
|
Rodríguez-Menchaca AA, Aréchiga-Figueroa IA, Sánchez-Chapula JA. The molecular basis of chloroethylclonidine block of inward rectifier (Kir2.1 and Kir4.1) K + channels. Pharmacol Rep 2016; 68:383-9. [DOI: 10.1016/j.pharep.2015.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 09/28/2015] [Accepted: 10/12/2015] [Indexed: 10/22/2022]
|
33
|
Zaika O, Palygin O, Tomilin V, Mamenko M, Staruschenko A, Pochynyuk O. Insulin and IGF-1 activate Kir4.1/5.1 channels in cortical collecting duct principal cells to control basolateral membrane voltage. Am J Physiol Renal Physiol 2016; 310:F311-21. [PMID: 26632606 PMCID: PMC4839479 DOI: 10.1152/ajprenal.00436.2015] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 11/30/2015] [Indexed: 01/12/2023] Open
Abstract
Potassium Kir4.1/5.1 channels are abundantly expressed at the basolateral membrane of principal cells in the cortical collecting duct (CCD), where they are thought to modulate transport rates by controlling transepithelial voltage. Insulin and insulin-like growth factor-1 (IGF-1) stimulate apically localized epithelial sodium channels (ENaC) to augment sodium reabsorption in the CCD. However, little is known about their actions on potassium channels localized at the basolateral membrane. In this study, we implemented patch-clamp analysis in freshly isolated murine CCD to assess the effect of these hormones on Kir4.1/5.1 at both single channel and cellular levels. We demonstrated that K(+)-selective conductance via Kir4.1/5.1 is the major contributor to the macroscopic current recorded from the basolateral side in principal cells. Acute treatment with 10 μM amiloride (ENaC blocker), 100 nM tertiapin-Q (TPNQ; ROMK inhibitor), and 100 μM ouabain (Na(+)-K(+)-ATPase blocker) failed to produce a measurable effect on the macroscopic current. In contrast, Kir4.1 inhibitor nortriptyline (100 μM), but not fluoxetine (100 μM), virtually abolished whole cell K(+)-selective conductance. Insulin (100 nM) markedly increased the open probability of Kir4.1/5.1 and nortriptyline-sensitive whole cell current, leading to significant hyperpolarization of the basolateral membrane. Inhibition of the phosphatidylinositol 3-kinase cascade with LY294002 (20 μM) abolished action of insulin on Kir4.1/5.1. IGF-1 had similar stimulatory actions on Kir4.1/5.1-mediated conductance only when applied at a higher (500 nM) concentration and was ineffective at 100 nM. We concluded that both insulin and, to a lesser extent, IGF-1 activate Kir4.1/5.1 channel activity and open probability to hyperpolarize the basolateral membrane, thereby facilitating Na(+) reabsorption in the CCD.
Collapse
Affiliation(s)
- Oleg Zaika
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas
| | - Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin; and
| | - Viktor Tomilin
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas; Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russian Federation
| | - Mykola Mamenko
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas
| | | | - Oleh Pochynyuk
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas;
| |
Collapse
|
34
|
Pilmore E, Hamilton KL. The Role of MicroRNAs in the Regulation of K(+) Channels in Epithelial Tissue. Front Physiol 2015; 6:352. [PMID: 26648872 PMCID: PMC4664832 DOI: 10.3389/fphys.2015.00352] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 11/09/2015] [Indexed: 12/27/2022] Open
Abstract
Our understanding of the modulation of proteins has shifted in direction with the discovery of microRNAs (miRs) over twenty years ago. MiRs are now in the “limelight” as these non-coding pieces of RNA (generally ~22 nucleotides long) result in altered translation and function of proteins. Indeed, miRs are now reported to be potential biomarkers of disease. Epithelial K+ channels play many roles in electrolyte and fluid homeostasis of the human body and have been suggested to be therapeutic targets of disease. Interestingly, the role of miRs in modulating K+ channels of epithelial tissues is only emerging now. This minireview focuses on recent novel findings into the role of miRs in the regulation of K+ channels of epithelia.
Collapse
Affiliation(s)
- Elliot Pilmore
- Department of Physiology, Otago School of Medical Sciences, University of Otago Dunedin, New Zealand
| | - Kirk L Hamilton
- Department of Physiology, Otago School of Medical Sciences, University of Otago Dunedin, New Zealand
| |
Collapse
|
35
|
Abstract
Astrocytes represent a highly heterogeneous population of neural cells primarily responsible for the homeostasis of the CNS. Astrocytes express multiple receptors for neurotransmitters, including the serotonin 5-HT2B receptors and interact with neurones at the synapse. Astroglia contribute to neurological diseases through homeostatic response, neuroprotection and reactivity. In major depression, astrocytes show signs of degeneration and are decreased in numbers, which may lead to a misbalance in neurotransmission and aberrant synaptic connectivity. In this review, we summarize astroglia-specific effects of major antidepressants and outline future strategies for astroglia-specific therapy in neuropsychiatric disorders.
Collapse
Affiliation(s)
- Liang Peng
- a 1 Laboratory of Metabolic Brain Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, No. 92 Beier Road, Heping District, Shenyang, PR China
| | | | - Li Gu
- a 1 Laboratory of Metabolic Brain Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, No. 92 Beier Road, Heping District, Shenyang, PR China
| | - Baoman Li
- a 1 Laboratory of Metabolic Brain Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, No. 92 Beier Road, Heping District, Shenyang, PR China
| |
Collapse
|
36
|
Wu SN, Huang YM, Kao CA, Chen BS, Lo YC. Investigations on contribution of glial inwardly-rectifying K(+) current to membrane potential and ion flux: an experimental and theoretical study. Kaohsiung J Med Sci 2014; 31:9-17. [PMID: 25600915 DOI: 10.1016/j.kjms.2014.10.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 07/01/2014] [Accepted: 08/20/2014] [Indexed: 01/29/2023] Open
Abstract
The inwardly rectifying K(+) current [IK(IR)] allows large inward K(+) currents at potentials negative to K(+) equilibrium potential (EK) and it becomes small outward K(+) currents at those positive to EK. How changes of such currents enriched in glial cells can influence the functions of glial cell, neurons, or both is not clearly defined, although mutations of Kir4.1 channels have been demonstrated to cause serious neurological disorders. In this study, we identified the presence of IK(IR) in human glioma cells (U373 and U87 cells). The amplitude of IK(IR) in U373 cells was subject to inhibition by amitriptyline, arecoline, or BaCl2. The activity of inwardly rectifying K(+) channels was also clearly detected, and single-channel conductance of these channels was calculated to be around 23 pS. Moreover, based on a simulation model derived from neuron-glial interaction mediated by ion flux, we further found out that incorporation of glial IK(IR) conductance into the model can significantly contribute to regulation of extracellular K(+) concentrations and glial resting potential, particularly during high-frequency stimulation. Glial cells and neurons can mutually modulate their expression of ion channels through K(+) ions released into the extracellular space. It is thus anticipated that glial IK(IR) may be a potential target utilized to influence the activity of neuronal and glial cells as well as their interaction.
Collapse
Affiliation(s)
- Sheng-Nan Wu
- Department of Physiology, National Cheng Kung University Medical College, Tainan City, Taiwan; Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan City, Taiwan.
| | - Yan-Ming Huang
- Department of Physiology, National Cheng Kung University Medical College, Tainan City, Taiwan
| | - Ching-An Kao
- Department of Physiology, National Cheng Kung University Medical College, Tainan City, Taiwan
| | - Bing-Shuo Chen
- Department of Anaesthesiology, Chi-Mei Medical Center, Tainan City, Taiwan
| | - Yi-Ching Lo
- Department of Pharmacology, Kaohsiung Medical University, Kaohsiung City, Taiwan
| |
Collapse
|
37
|
Caldarone BJ, Zachariou V, King SL. Rodent models of treatment-resistant depression. Eur J Pharmacol 2014; 753:51-65. [PMID: 25460020 DOI: 10.1016/j.ejphar.2014.10.063] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 09/16/2014] [Accepted: 10/09/2014] [Indexed: 01/06/2023]
Abstract
Major depression is a prevalent and debilitating disorder and a substantial proportion of patients fail to reach remission following standard antidepressant pharmacological treatment. Limited efficacy with currently available antidepressant drugs highlights the need to develop more effective medications for treatment- resistant patients and emphasizes the importance of developing better preclinical models that focus on treatment- resistant populations. This review discusses methods to adapt and refine rodent behavioral models that are predictive of antidepressant efficacy to identify populations that show reduced responsiveness or are resistant to traditional antidepressants. Methods include separating antidepressant responders from non-responders, administering treatments that render animals resistant to traditional pharmacological treatments, and identifying genetic models that show antidepressant resistance. This review also examines pharmacological and non-pharmacological treatments regimes that have been effective in refractory patients and how some of these approaches have been used to validate animal models of treatment-resistant depression. The goals in developing rodent models of treatment-resistant depression are to understand the neurobiological mechanisms involved in antidepressant resistance and to develop valid models to test novel therapies that would be effective in patients that do not respond to traditional monoaminergic antidepressants.
Collapse
Affiliation(s)
- Barbara J Caldarone
- Department of Neurology, Brigham and Women's Hospital and NeuroBehavior Laboratory, Harvard NeuroDiscovery Center, 77 Avenue Louis Pasteur, Boston, MA 02115, USA.
| | - Venetia Zachariou
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, 1425 Madison Ave, New York, NY 10029, USA
| | - Sarah L King
- School of Psychology, University of Sussex, Brighton, East Sussex, UK
| |
Collapse
|
38
|
Cheung So E, Lo YC, Chen LT, Kao CA, Wu SN. High effectiveness of triptolide, an active diterpenoid triepoxide, in suppressing Kir-channel currents from human glioma cells. Eur J Pharmacol 2014; 738:332-41. [DOI: 10.1016/j.ejphar.2014.05.059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 05/23/2014] [Accepted: 05/23/2014] [Indexed: 11/17/2022]
|
39
|
Astrocyte Kir4.1 ion channel deficits contribute to neuronal dysfunction in Huntington's disease model mice. Nat Neurosci 2014; 17:694-703. [PMID: 24686787 PMCID: PMC4064471 DOI: 10.1038/nn.3691] [Citation(s) in RCA: 420] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 03/06/2014] [Indexed: 12/12/2022]
Abstract
Huntington's disease (HD) is characterized by striatal medium spiny neuron (MSN) dysfunction, but the underlying mechanisms remain unclear. We explored roles for astrocytes, which display mutant huntingtin in HD patients and mouse models. We found that symptom onset in R6/2 and Q175 HD mouse models is not associated with classical astrogliosis, but is associated with decreased Kir4.1 K+ channel functional expression, leading to elevated in vivo levels of striatal extracellular K+, which increased MSN excitability in vitro. Viral delivery of Kir4.1 channels to striatal astrocytes restored Kir4.1 function, normalized extracellular K+, recovered aspects of MSN dysfunction, prolonged survival and attenuated some motor phenotypes in R6/2 mice. These findings indicate that components of altered MSN excitability in HD may be caused by heretofore unknown disturbances of astrocyte–mediated K+ homeostasis, revealing astrocytes and Kir4.1 channels as novel therapeutic targets.
Collapse
|
40
|
Expressional Analysis of Inwardly Rectifying Kir4.1 Channels in Groggy Rats, a Rat Model of Absence Seizures. ARCHIVES OF NEUROSCIENCE 2014. [DOI: 10.5812/archneurosci.18651] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
41
|
Swale DR, Kharade SV, Denton JS. Cardiac and renal inward rectifier potassium channel pharmacology: emerging tools for integrative physiology and therapeutics. Curr Opin Pharmacol 2013; 15:7-15. [PMID: 24721648 DOI: 10.1016/j.coph.2013.11.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 11/05/2013] [Indexed: 01/01/2023]
Abstract
Inward rectifier potassium (Kir) channels play fundamental roles in cardiac and renal function and may represent unexploited drug targets for cardiovascular diseases. However, the limited pharmacology of Kir channels has slowed progress toward exploring their integrative physiology and therapeutic potential. Here, we review recent progress toward developing the small-molecule pharmacology for Kir2.x, Kir4.1, and Kir7.1 and discuss common mechanistic themes that may help guide future Kir channel-directed drug discovery efforts.
Collapse
Affiliation(s)
- Daniel R Swale
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN 37232, United States
| | - Sujay V Kharade
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN 37232, United States
| | - Jerod S Denton
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN 37232, United States; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, United States; Institute of Chemical Biology, Vanderbilt University Medical Center, Nashville, TN 37232, United States; Institute for Global Health, Vanderbilt University Medical Center, Nashville, TN 37232, United States.
| |
Collapse
|
42
|
Denton JS, Pao AC, Maduke M. Novel diuretic targets. Am J Physiol Renal Physiol 2013; 305:F931-42. [PMID: 23863472 PMCID: PMC3798746 DOI: 10.1152/ajprenal.00230.2013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 07/12/2013] [Indexed: 01/11/2023] Open
Abstract
As the molecular revolution continues to inform a deeper understanding of disease mechanisms and pathways, there exist unprecedented opportunities for translating discoveries at the bench into novel therapies for improving human health. Despite the availability of several different classes of antihypertensive medications, only about half of the 67 million Americans with hypertension manage their blood pressure appropriately. A broader selection of structurally diverse antihypertensive drugs acting through different mechanisms would provide clinicians with greater flexibility in developing effective treatment regimens for an increasingly diverse and aging patient population. An emerging body of physiological, genetic, and pharmacological evidence has implicated several renal ion-transport proteins, or regulators thereof, as novel, yet clinically unexploited, diuretic targets. These include the renal outer medullary potassium channel, ROMK (Kir1.1), Kir4.1/5.1 potassium channels, ClC-Ka/b chloride channels, UTA/B urea transporters, the chloride/bicarbonate exchanger pendrin, and the STE20/SPS1-related proline/alanine-rich kinase (SPAK). The molecular pharmacology of these putative targets is poorly developed or lacking altogether; however, recent efforts by a few academic and pharmaceutical laboratories have begun to lessen this critical barrier. Here, we review the evidence in support of the aforementioned proteins as novel diuretic targets and highlight examples where progress toward developing small-molecule pharmacology has been made.
Collapse
Affiliation(s)
- Jerod S Denton
- T4208 Medical Center North, 1161 21st Ave. South, Nashville, TN 37232.
| | | | | |
Collapse
|
43
|
Membrane channels as integrators of G-protein-mediated signaling. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:521-31. [PMID: 24028827 DOI: 10.1016/j.bbamem.2013.08.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 08/14/2013] [Accepted: 08/21/2013] [Indexed: 01/03/2023]
Abstract
A variety of extracellular stimuli regulate cellular responses via membrane receptors. A well-known group of seven-transmembrane domain-containing proteins referred to as G protein-coupled receptors, directly couple with the intracellular GTP-binding proteins (G proteins) across cell membranes and trigger various cellular responses by regulating the activity of several enzymes as well as ion channels. Many specific populations of ion channels are directly controlled by G proteins; however, indirect modulation of some channels by G protein-dependent phosphorylation events and lipid metabolism is also observed. G protein-mediated diverse modifications affect the ion channel activities and spatio-temporally regulate membrane potentials as well as of intracellular Ca(2+) concentrations in both excitatory and non-excitatory cells. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé.
Collapse
|
44
|
Nagao Y, Harada Y, Mukai T, Shimizu S, Okuda A, Fujimoto M, Ono A, Sakagami Y, Ohno Y. Expressional analysis of the astrocytic Kir4.1 channel in a pilocarpine-induced temporal lobe epilepsy model. Front Cell Neurosci 2013; 7:104. [PMID: 23922547 PMCID: PMC3734973 DOI: 10.3389/fncel.2013.00104] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 06/16/2013] [Indexed: 11/23/2022] Open
Abstract
The inwardly rectifying potassium (Kir) channel Kir4.1 in brain astrocytes mediates spatial K+ buffering and regulates neural activities. Recent studies have shown that loss-of-function mutations in the human gene KCNJ10 encoding Kir4.1 cause epileptic seizures, suggesting a close relationship between the Kir4.1 channel function and epileptogenesis. Here, we performed expressional analysis of Kir4.1 in a pilocarpine-induced rat model of temporal lobe epilepsy (TLE) to explore the role of Kir4.1 channels in modifying TLE epileptogenesis. Treatment of rats with pilocarpine (350 mg/kg, i.p.) induced acute status epilepticus, which subsequently caused spontaneous seizures 7–8 weeks after the pilocarpine treatment. Western blot analysis revealed that TLE rats (interictal condition) showed significantly higher levels of Kir4.1 than the control animals in the cerebral cortex, striatum, and hypothalamus. However, the expression of other Kir subunits, Kir5.1 and Kir2.1, remained unaltered. Immunohistochemical analysis illustrated that Kir4.1-immunoreactivity-positive astrocytes in the pilocarpine-induced TLE model were markedly increased in most of the brain regions examined, concomitant with an increase in the number of glial fibrillary acidic protein (GFAP)-positive astrocytes. In addition, Kir4.1 expression ratios relative to the number of astrocytes (Kir4.1-positive cells/GFAP-positive cells) were region-specifically elevated in the amygdala (i.e., medial and cortical amygdaloid nuclei) and sensory cortex. The present study demonstrated for the first time that the expression of astrocytic Kir4.1 channels was elevated in a pilocarpine-induced TLE model, especially in the amygdala, suggesting that astrocytic Kir4.1 channels play a role in modifying TLE epileptogenesis, possibly by acting as an inhibitory compensatory mechanism.
Collapse
Affiliation(s)
- Yuki Nagao
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences Osaka, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Harada Y, Nagao Y, Shimizu S, Serikawa T, Terada R, Fujimoto M, Okuda A, Mukai T, Sasa M, Kurachi Y, Ohno Y. Expressional analysis of inwardly rectifying Kir4.1 channels in Noda epileptic rat (NER). Brain Res 2013; 1517:141-9. [PMID: 23603404 DOI: 10.1016/j.brainres.2013.04.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 03/31/2013] [Accepted: 04/09/2013] [Indexed: 11/30/2022]
Abstract
The inwardly rectifying potassium channel subunit Kir4.1 is expressed in brain astrocytes and involved in spatial K(+) buffering, regulating neural activity. To explore the pathophysiological alterations of Kir4.1 channels in epileptic disorders, we analyzed interictal expressional levels of Kir4.1 in the Noda epileptic rat (NER), a hereditary animal model for generalized tonic-clonic (GTC) seizures. Western blot analysis showed that Kir4.1 expression in NERs was significantly reduced in the occipito-temporal cortical region and thalamus. However, the expression of Kir5.1, another Kir subunit mediating spatial K(+) buffering, remained unaltered in any brain regions examined. Immunohistochemical analysis revealed that Kir4.1 was primarily expressed in glial fibrillary acidic protein (GFAP)-positive astrocytes (somata) and foot processes clustered around neurons proved with anti-neuronal nuclear antigen (NeuN) antibody. In NERs, Kir4.1 expression in astrocytic processes was region-selectively diminished in the amygdaloid nuclei (i.e., medial amygdaloid nucleus and basomedial amygdaloid nucleus) while Kir4.1 expression in astrocytic somata was unchanged. Furthermore, the amygdala regions with reduced Kir4.1 expression showed a marked elevation of Fos protein expression following GTC seizures. The present results suggest that reduced activity of astrocytic Kir4.1 channels in the amygdala is involved in limbic hyperexcitability in NERs.
Collapse
Affiliation(s)
- Yuya Harada
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, Osaka 569-1094, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Abstract
Oligodendrocyte precursor cells (OPCs) are the major source of myelinating oligodendrocytes during development. These progenitors are highly abundant at birth and persist in the adult where they are distributed throughout the brain. The large abundance of OPCs after completion of myelination challenges their unique role as progenitors in the healthy adult brain. Here we show that adult OPCs of the barrel cortex sense fine extracellular K(+) increases generated by neuronal activity, a property commonly assigned to differentiated astrocytes rather than to progenitors. Biophysical, pharmacological, and single-cell RT-PCR analyses demonstrate that this ability of OPCs establishes itself progressively through the postnatal upregulation of Kir4.1 K(+) channels. In animals with advanced cortical myelination, extracellular stimulation of layer V axons induces slow K(+) currents in OPCs, which amplitude correlates with presynaptic action potential rate. Moreover, using paired recordings, we demonstrate that the discharge of a single neuron can be detected by nearby adult OPCs, indicating that these cells are strategically located to detect local changes in extracellular K(+) concentration during physiological neuronal activity. These results identify a novel unitary neuron-OPC connection, which transmission does not rely on neurotransmitter release and appears late in development. Beyond their abundance in the mature brain, the postnatal emergence of a physiological response of OPCs to neuronal network activity supports the view that in the adult these cells are not progenitors only.
Collapse
|
47
|
Czéh B, Di Benedetto B. Antidepressants act directly on astrocytes: evidences and functional consequences. Eur Neuropsychopharmacol 2013; 23:171-85. [PMID: 22609317 DOI: 10.1016/j.euroneuro.2012.04.017] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 04/27/2012] [Indexed: 11/24/2022]
Abstract
Post-mortem histopathological studies report on reduced glial cell numbers in various frontolimbic areas of depressed patients implying that glial loss together with abnormal functioning could contribute to the pathophysiology of mood disorders. Astrocytes are regarded as the most abundant cell type in the brain and known for their housekeeping functions, but as recent developments suggest, they are also dynamic regulators of synaptogenesis, synaptic strength and stability and they control adult hippocampal neurogenesis. The primary aim of this review was to summarize the abundant experimental evidences demonstrating that antidepressant therapies have profound effect on astrocytes. Antidepressants modify astroglial physiology, morphology and by affecting gliogenesis they probably even regulate glial cell numbers. Antidepressants affect intracellular signaling pathways and gene expression of astrocytes, as well as the expression of receptors and the release of various trophic factors. We also assess the potential functional consequences of these changes on glutamate and glucose homeostasis and on synaptic communication between the neurons. We propose here a hypothesis that antidepressant treatment not only affects neurons, but also activates astrocytes, triggering them to carry out specific functions that result in the reactivation of cortical plasticity and can lead to the readjustment of abnormal neuronal networks. We argue here that these astrocyte specific changes are likely to contribute to the therapeutic effectiveness of the currently available antidepressant treatments and the better understanding of these cellular and molecular processes could help us to identify novel targets for the development of antidepressant drugs.
Collapse
Affiliation(s)
- Boldizsár Czéh
- Max-Planck-Institute of Psychiatry, 80804 Munich, Germany.
| | | |
Collapse
|
48
|
Small-molecule modulators of inward rectifier K+ channels: recent advances and future possibilities. Future Med Chem 2011; 2:757-74. [PMID: 20543968 DOI: 10.4155/fmc.10.179] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Inward rectifier potassium (Kir) channels have been postulated as therapeutic targets for several common disorders including hypertension, cardiac arrhythmias and pain. With few exceptions, however, the small-molecule pharmacology of this family is limited to nonselective cardiovascular and neurologic drugs with off-target activity toward inward rectifiers. Consequently, the actual therapeutic potential and 'drugability' of most Kir channels has not yet been determined experimentally. The purpose of this review is to provide a comprehensive summary of publicly disclosed Kir channel small-molecule modulators and highlight recent targeted drug-discovery efforts toward Kir1.1 and Kir2.1. The review concludes with a brief speculation on how the field of Kir channel pharmacology will develop over the coming years and a discussion of the increasingly important role academic laboratories will play in this progress.
Collapse
|
49
|
Wenker IC, Kréneisz O, Nishiyama A, Mulkey DK. Astrocytes in the retrotrapezoid nucleus sense H+ by inhibition of a Kir4.1-Kir5.1-like current and may contribute to chemoreception by a purinergic mechanism. J Neurophysiol 2010; 104:3042-52. [PMID: 20926613 PMCID: PMC3007661 DOI: 10.1152/jn.00544.2010] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Accepted: 09/29/2010] [Indexed: 11/22/2022] Open
Abstract
Central chemoreception is the mechanism by which CO(2)/pH sensors regulate breathing in response to tissue pH changes. There is compelling evidence that pH-sensitive neurons in the retrotrapezoid nucleus (RTN) are important chemoreceptors. Evidence also indicates that CO(2)/H(+)-evoked adenosine 5'-triphosphate (ATP) release in the RTN, from pH-sensitive astrocytes, contributes to chemoreception. However, mechanism(s) by which RTN astrocytes sense pH is unknown and their contribution to chemoreception remains controversial. Here, we use the brain slice preparation and a combination of patch-clamp electrophysiology and immunohistochemistry to confirm that RTN astrocytes are pH sensitive and to determine mechanisms by which they sense pH. We show that pH-sensitive RTN glia are immunoreactive for aldehyde dehydrogenase 1L1, a marker of astrocytes. In HEPES buffer the pH-sensitive current expressed by RTN astrocytes reversed near E(K(+)) (the equilibrium potential for K(+)) and was inhibited by Ba(2+) and desipramine (blocker of Kir4.1-containing channels), characteristics most consistent with heteromeric Kir4.1-Kir5.1 channels. In bicarbonate buffer, the sodium/bicarbonate cotransporter also contributed to the CO(2)/H(+)-sensitive current in RTN astrocytes. To test the hypothesis that RTN astrocytes contribute to chemoreception by a purinergic mechanism, we used fluorocitrate to selectively depolarize astrocytes while measuring neuronal activity. We found that fluorocitrate increased baseline activity and pH sensitivity of RTN neurons by a P2-receptor-dependent mechanism, suggesting that astrocytes may release ATP to activate RTN chemoreceptors. We also found in bicarbonate but not HEPES buffer that P2-receptor antagonists decreased CO(2) sensitivity of RTN neurons. We conclude that RTN astrocytes sense CO(2)/H(+) in part by inhibition of a Kir4.1-Kir5.1-like current and may provide an excitatory purinergic drive to pH-sensitive neurons.
Collapse
Affiliation(s)
- Ian C Wenker
- University of Connecticut, Department of Physiology and Neurobiology, 75 N. Eagleville Rd., Storrs, CT 06269, USA
| | | | | | | |
Collapse
|
50
|
Pan CC, Shaw CF, Huang JK, Kuo CC, Kuo DH, Shieh P, Lu T, Chen WC, Ho CM, Jan CR. Effect of nortriptyline on cytosolic Ca2+ regulation and viability in PC3 human prostate cancer cells. Drug Dev Res 2010. [DOI: 10.1002/ddr.20377] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|