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Macias-Contreras M, Granados JP, Hernandez DS. ION Thallos-HTL: a fluorescent thallium indicator that enables cell-selective and localizable thallium flux assays. Org Biomol Chem 2024; 22:4748-4756. [PMID: 38804097 DOI: 10.1039/d4ob00535j] [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] [Indexed: 05/29/2024]
Abstract
Ion channels are essential proteins for all organisms. Electrophysiology is a useful and commonly employed method to study ion channels, however there is a need for operationally simpler, cost-effective and higher throughput techniques to study ion channel functions in their native environments. Fluorescent ion indicators, such as Fluo-4 and Thallos, have been used for decades to study ion channel activity by measuring the flux of ions through channels of interest. In this work, we present ION Thallos-HTL, a thallium indicator that can be localized using HaloTag technology. This novel indicator enables specific labeling of cells and intracellular compartments in live cells and responds to changes in thallium concentration within these environments. We demonstrate the utility of ION Thallos-HTL by conducting a thallium flux assay using high-throughput instrumentation in a mixed cell population where some cells are expressing HaloTag and some are not.
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2
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Miyano K, Nonaka M, Sakamoto M, Murofushi M, Yoshida Y, Komura K, Ohbuchi K, Higami Y, Fujii H, Uezono Y. The Inhibition of TREK-1 K + Channels via Multiple Compounds Contained in the Six Kamikihito Components, Potentially Stimulating Oxytocin Neuron Pathways. Int J Mol Sci 2024; 25:4907. [PMID: 38732124 PMCID: PMC11084865 DOI: 10.3390/ijms25094907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 04/19/2024] [Accepted: 04/26/2024] [Indexed: 05/13/2024] Open
Abstract
Oxytocin, a significant pleiotropic neuropeptide, regulates psychological stress adaptation and social communication, as well as peripheral actions, such as uterine contraction and milk ejection. Recently, a Japanese Kampo medicine called Kamikihito (KKT) has been reported to stimulate oxytocin neurons to induce oxytocin secretion. Two-pore-domain potassium channels (K2P) regulate the resting potential of excitable cells, and their inhibition results in accelerated depolarization that elicits neuronal and endocrine cell activation. We assessed the effects of KKT and 14 of its components on a specific K2P, the potassium channel subfamily K member 2 (TREK-1), which is predominantly expressed in oxytocin neurons in the central nervous system (CNS). KKT inhibited the activity of TREK-1 induced via the channel activator ML335. Six of the 14 components of KKT inhibited TREK-1 activity. Additionally, we identified that 22 of the 41 compounds in the six components exhibited TREK-1 inhibitory effects. In summary, several compounds included in KKT partially activated oxytocin neurons by inhibiting TREK-1. The pharmacological effects of KKT, including antistress effects, may be partially mediated through the oxytocin pathway.
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Affiliation(s)
- Kanako Miyano
- Department of Pain Control Research, The Jikei University School of Medicine, Tokyo 105-8461, Japan; (K.M.); (M.N.); (M.S.); (M.M.); (K.K.)
- Department of Dentistry, National Cancer Center Hospital, Tokyo 104-0045, Japan
- Laboratory of Pharmacotherapeutics, Faculty of Pharmacy, Juntendo University, Chiba 279-0013, Japan
| | - Miki Nonaka
- Department of Pain Control Research, The Jikei University School of Medicine, Tokyo 105-8461, Japan; (K.M.); (M.N.); (M.S.); (M.M.); (K.K.)
| | - Masahiro Sakamoto
- Department of Pain Control Research, The Jikei University School of Medicine, Tokyo 105-8461, Japan; (K.M.); (M.N.); (M.S.); (M.M.); (K.K.)
| | - Mika Murofushi
- Department of Pain Control Research, The Jikei University School of Medicine, Tokyo 105-8461, Japan; (K.M.); (M.N.); (M.S.); (M.M.); (K.K.)
- Laboratory of Medicinal Chemistry, School of Pharmacy, Kitasato University, Tokyo 108-8641, Japan;
| | - Yuki Yoshida
- Laboratory of Molecular Pathology and Metabolic Disease, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Chiba 278-8510, Japan; (Y.Y.); (Y.H.)
| | - Kyoko Komura
- Department of Pain Control Research, The Jikei University School of Medicine, Tokyo 105-8461, Japan; (K.M.); (M.N.); (M.S.); (M.M.); (K.K.)
- Laboratory of Medicinal Chemistry, School of Pharmacy, Kitasato University, Tokyo 108-8641, Japan;
| | - Katsuya Ohbuchi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan;
| | - Yoshikazu Higami
- Laboratory of Molecular Pathology and Metabolic Disease, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Chiba 278-8510, Japan; (Y.Y.); (Y.H.)
| | - Hideaki Fujii
- Laboratory of Medicinal Chemistry, School of Pharmacy, Kitasato University, Tokyo 108-8641, Japan;
| | - Yasuhito Uezono
- Department of Pain Control Research, The Jikei University School of Medicine, Tokyo 105-8461, Japan; (K.M.); (M.N.); (M.S.); (M.M.); (K.K.)
- Supportive and Palliative Care Research Support Office, National Cancer Center Hospital East, Chiba 277-8577, Japan
- Department of Comprehensive Oncology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8523, Japan
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3
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Smith E, Dickson L, Pickford P, Rowland A, Shumate J, Perez K, Scampavia L, Hernandez D, Spicer TP. Protocol for kinetic mode potassium channel assays on common plate readers and microscopes. SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2024; 29:100148. [PMID: 38677875 DOI: 10.1016/j.slasd.2024.100148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 02/02/2024] [Accepted: 03/01/2024] [Indexed: 04/29/2024]
Abstract
Fluorescence-based potassium channel assays are typically run on expensive, hard to obtain, fluorescence imaging kinetic plate readers that are uncommon in most laboratories. Here we describe the use of the Brilliant Thallium Snapshot assay to conduct an endpoint potassium channel assay, so that it can be used across multiple plate reader platforms that are more common in many labs. These methods will allow users to identify modulators of potassium channels. For this work, we have taken a kinetic mode Molecular Devices FLIPR based protocol and adapted it to be utilized on endpoint plate readers, such as the BMG Labtech PHERAstar, to identify activators of GIRK channels in CHO cells. We demonstrate that both plate readers are functionally competent at generating excellent Z' values which makes them ideally suited to finding corollary hits from the Sigma LOPAC 1,280 screening collection. Importantly, this assay has also been validated using a high content reader, demonstrating the possibility of spatially resolving signals from individual cells within a mixed cell population. The compendium of these results shows the flexibility, accessibility and functionality of endpoint-compatible potassium channel assay readouts on more common plate readers.
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Affiliation(s)
- Emery Smith
- The Herbert Wertheim UF Scripps Institute for Biomedical Innovation and Technology, Department of Molecular Medicine, 130 Scripps Way #1A1, Jupiter, FL 33458, United States
| | - Louise Dickson
- Cerevance Ltd., 418 Cambridge Science Park Milton Rd, Milton, Cambridge CB4 0PZ, United Kingdom
| | - Philip Pickford
- Cerevance Ltd., 418 Cambridge Science Park Milton Rd, Milton, Cambridge CB4 0PZ, United Kingdom
| | - Anna Rowland
- Cerevance Ltd., 418 Cambridge Science Park Milton Rd, Milton, Cambridge CB4 0PZ, United Kingdom
| | - Justin Shumate
- The Herbert Wertheim UF Scripps Institute for Biomedical Innovation and Technology, Department of Molecular Medicine, 130 Scripps Way #1A1, Jupiter, FL 33458, United States
| | - Katherine Perez
- The Herbert Wertheim UF Scripps Institute for Biomedical Innovation and Technology, Department of Molecular Medicine, 130 Scripps Way #1A1, Jupiter, FL 33458, United States
| | - Louis Scampavia
- The Herbert Wertheim UF Scripps Institute for Biomedical Innovation and Technology, Department of Molecular Medicine, 130 Scripps Way #1A1, Jupiter, FL 33458, United States
| | | | - Timothy P Spicer
- The Herbert Wertheim UF Scripps Institute for Biomedical Innovation and Technology, Department of Molecular Medicine, 130 Scripps Way #1A1, Jupiter, FL 33458, United States.
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4
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Gilleran JA, Ashraf K, Delvillar M, Eck T, Fondekar R, Miller EB, Hutchinson A, Dong A, Seitova A, De Souza ML, Augeri D, Halabelian L, Siekierka J, Rotella DP, Gordon J, Childers WE, Grier MC, Staker BL, Roberge JY, Bhanot P. Structure-Activity Relationship of a Pyrrole Based Series of PfPKG Inhibitors as Anti-Malarials. J Med Chem 2024; 67:3467-3503. [PMID: 38372781 DOI: 10.1021/acs.jmedchem.3c01795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Controlling malaria requires new drugs against Plasmodium falciparum. The P. falciparum cGMP-dependent protein kinase (PfPKG) is a validated target whose inhibitors could block multiple steps of the parasite's life cycle. We defined the structure-activity relationship (SAR) of a pyrrole series for PfPKG inhibition. Key pharmacophores were modified to enable full exploration of chemical diversity and to gain knowledge about an ideal core scaffold. In vitro potency against recombinant PfPKG and human PKG were used to determine compound selectivity for the parasite enzyme. P. berghei sporozoites and P. falciparum asexual blood stages were used to assay multistage antiparasitic activity. Cellular specificity of compounds was evaluated using transgenic parasites expressing PfPKG carrying a substituted "gatekeeper" residue. The structure of PfPKG bound to an inhibitor was solved, and modeling using this structure together with computational tools was utilized to understand SAR and establish a rational strategy for subsequent lead optimization.
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Affiliation(s)
- John A Gilleran
- Rutgers Molecular Design and Synthesis Core, Office for Research, Rutgers University, 610 Taylor Road, Piscataway, New Jersey 08854, United States
| | - Kutub Ashraf
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, 225 Warren Street, Newark, New Jersey 07103, United States
| | - Melvin Delvillar
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, 225 Warren Street, Newark, New Jersey 07103, United States
| | - Tyler Eck
- Department of Chemistry and Biochemistry and Sokol Institute of Pharmaceutical Life Sciences, Montclair State University, Montclair, New Jersey 07043, United States
| | - Raheel Fondekar
- Rutgers Molecular Design and Synthesis Core, Office for Research, Rutgers University, 610 Taylor Road, Piscataway, New Jersey 08854, United States
- Rutgers School of Pharmacy, 160 Frelinghuysen Road, Piscataway, New Jersey 08854, United States
| | - Edward B Miller
- Schrödinger, Inc., 1540 Broadway, 24th Floor, New York, New York 10036, United States
| | - Ashley Hutchinson
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7, Canada
| | - Aiping Dong
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7, Canada
| | - Alma Seitova
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7, Canada
| | - Mariana Laureano De Souza
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, 225 Warren Street, Newark, New Jersey 07103, United States
| | - David Augeri
- Rutgers Molecular Design and Synthesis Core, Office for Research, Rutgers University, 610 Taylor Road, Piscataway, New Jersey 08854, United States
- Schrödinger, Inc., 1540 Broadway, 24th Floor, New York, New York 10036, United States
| | - Levon Halabelian
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - John Siekierka
- Department of Chemistry and Biochemistry and Sokol Institute of Pharmaceutical Life Sciences, Montclair State University, Montclair, New Jersey 07043, United States
| | - David P Rotella
- Department of Chemistry and Biochemistry and Sokol Institute of Pharmaceutical Life Sciences, Montclair State University, Montclair, New Jersey 07043, United States
| | - John Gordon
- Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia, Pennsylvania 19140, United States
| | - Wayne E Childers
- Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia, Pennsylvania 19140, United States
| | - Mark C Grier
- Rutgers Molecular Design and Synthesis Core, Office for Research, Rutgers University, 610 Taylor Road, Piscataway, New Jersey 08854, United States
| | - Bart L Staker
- Seattle Structural Genomics Center for Infectious Disease, Seattle, Washington 98109, United States
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington 98109, United States
| | - Jacques Y Roberge
- Rutgers Molecular Design and Synthesis Core, Office for Research, Rutgers University, 610 Taylor Road, Piscataway, New Jersey 08854, United States
| | - Purnima Bhanot
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, 225 Warren Street, Newark, New Jersey 07103, United States
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Gupta N, Waas B, Austin D, De Mazière AM, Kujala P, Stockwell AD, Li T, Yaspan BL, Klumperman J, Scales SJ. Apolipoprotein L1 (APOL1) renal risk variant-mediated podocyte cytotoxicity depends on African haplotype and surface expression. Sci Rep 2024; 14:3765. [PMID: 38355600 PMCID: PMC10866943 DOI: 10.1038/s41598-024-53298-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 01/30/2024] [Indexed: 02/16/2024] Open
Abstract
Homozygous Apolipoprotein L1 (APOL1) variants G1 and G2 cause APOL1-mediated kidney disease, purportedly acting as surface cation channels in podocytes. APOL1-G0 exhibits various single nucleotide polymorphisms, most commonly haplotype E150K, M228I and R255K ("KIK"; the Reference Sequence is "EMR"), whereas variants G1 and G2 are mostly found in a single "African" haplotype background ("EIK"). Several labs reported cytotoxicity with risk variants G1 and G2 in KIK or EIK background haplotypes, but used HEK-293 cells and did not verify equal surface expression. To see if haplotype matters in a more relevant cell type, we induced APOL1-G0, G1 and G2 EIK, KIK and EMR at comparable surface levels in immortalized podocytes. G1 and G2 risk variants (but not G0) caused dose-dependent podocyte death within 48h only in their native African EIK haplotype and correlated with K+ conductance (thallium FLIPR). We ruled out differences in localization and trafficking, except for possibly greater surface clustering of cytotoxic haplotypes. APOL1 surface expression was required, since Brefeldin A rescued cytotoxicity; and cytoplasmic isoforms vB3 and vC were not cytotoxic. Thus, APOL1-EIK risk variants kill podocytes in a dose and haplotype-dependent manner (as in HEK-293 cells), whereas unlike in HEK-293 cells the KIK risk variants did not.
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Affiliation(s)
- Nidhi Gupta
- Department of Discovery Immunology, Genentech, 1 DNA Way, South San Francisco, CA, 94080, USA
- Department of Molecular Biology, Genentech, 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Bridget Waas
- Department of Discovery Immunology, Genentech, 1 DNA Way, South San Francisco, CA, 94080, USA
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Daniel Austin
- Department of Biochemical and Cellular Pharmacology, Genentech, 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Ann M De Mazière
- Section of Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Pekka Kujala
- Section of Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Amy D Stockwell
- Department of Human Genetics, Genentech, 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Tianbo Li
- Department of Biochemical and Cellular Pharmacology, Genentech, 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Brian L Yaspan
- Department of Human Genetics, Genentech, 1 DNA Way, South San Francisco, CA, 94080, USA.
| | - Judith Klumperman
- Section of Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Suzie J Scales
- Department of Discovery Immunology, Genentech, 1 DNA Way, South San Francisco, CA, 94080, USA.
- Department of Molecular Biology, Genentech, 1 DNA Way, South San Francisco, CA, 94080, USA.
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6
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Bazzone A, Barthmes M, George C, Brinkwirth N, Zerlotti R, Prinz V, Cole K, Friis S, Dickson A, Rice S, Lim J, Fern Toh M, Mohammadi M, Pau D, Stone DJ, Renger JJ, Fertig N. A Comparative Study on the Lysosomal Cation Channel TMEM175 Using Automated Whole-Cell Patch-Clamp, Lysosomal Patch-Clamp, and Solid Supported Membrane-Based Electrophysiology: Functional Characterization and High-Throughput Screening Assay Development. Int J Mol Sci 2023; 24:12788. [PMID: 37628970 PMCID: PMC10454728 DOI: 10.3390/ijms241612788] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 08/09/2023] [Accepted: 08/12/2023] [Indexed: 08/27/2023] Open
Abstract
The lysosomal cation channel TMEM175 is a Parkinson's disease-related protein and a promising drug target. Unlike whole-cell automated patch-clamp (APC), lysosomal patch-clamp (LPC) facilitates physiological conditions, but is not yet suitable for high-throughput screening (HTS) applications. Here, we apply solid supported membrane-based electrophysiology (SSME), which enables both direct access to lysosomes and high-throughput electrophysiological recordings. In SSME, ion translocation mediated by TMEM175 is stimulated using a concentration gradient at a resting potential of 0 mV. The concentration-dependent K+ response exhibited an I/c curve with two distinct slopes, indicating the existence of two conducting states. We measured H+ fluxes with a permeability ratio of PH/PK = 48,500, which matches literature findings from patch-clamp studies, validating the SSME approach. Additionally, TMEM175 displayed a high pH dependence. Decreasing cytosolic pH inhibited both K+ and H+ conductivity of TMEM175. Conversely, lysosomal pH and pH gradients did not have major effects on TMEM175. Finally, we developed HTS assays for drug screening and evaluated tool compounds (4-AP, Zn as inhibitors; DCPIB, arachidonic acid, SC-79 as enhancers) using SSME and APC. Additionally, we recorded EC50 data for eight blinded TMEM175 enhancers and compared the results across all three assay technologies, including LPC, discussing their advantages and disadvantages.
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Affiliation(s)
- Andre Bazzone
- Nanion Technologies, Ganghoferstr. 70a, 80339 Munich, Germany (V.P.); (S.F.)
| | - Maria Barthmes
- Nanion Technologies, Ganghoferstr. 70a, 80339 Munich, Germany (V.P.); (S.F.)
| | - Cecilia George
- Nanion Technologies, Ganghoferstr. 70a, 80339 Munich, Germany (V.P.); (S.F.)
| | - Nina Brinkwirth
- Nanion Technologies, Ganghoferstr. 70a, 80339 Munich, Germany (V.P.); (S.F.)
| | - Rocco Zerlotti
- Nanion Technologies, Ganghoferstr. 70a, 80339 Munich, Germany (V.P.); (S.F.)
- RIGeL-Regensburg International Graduate School of Life Sciences, University of Regensburg, 93053 Regensburg, Germany
| | - Valentin Prinz
- Nanion Technologies, Ganghoferstr. 70a, 80339 Munich, Germany (V.P.); (S.F.)
| | - Kim Cole
- Nanion Technologies, Ganghoferstr. 70a, 80339 Munich, Germany (V.P.); (S.F.)
| | - Søren Friis
- Nanion Technologies, Ganghoferstr. 70a, 80339 Munich, Germany (V.P.); (S.F.)
| | - Alexander Dickson
- SB Drug Discovery, West of Scotland Science Park, Glasgow G20 0XA, UK; (A.D.); (S.R.)
| | - Simon Rice
- SB Drug Discovery, West of Scotland Science Park, Glasgow G20 0XA, UK; (A.D.); (S.R.)
| | - Jongwon Lim
- Cerevel Therapeutics, 222 Jacobs St, Cambridge, MA 02141, USA; (J.L.); (M.F.T.); (D.J.S.); (J.J.R.)
| | - May Fern Toh
- Cerevel Therapeutics, 222 Jacobs St, Cambridge, MA 02141, USA; (J.L.); (M.F.T.); (D.J.S.); (J.J.R.)
| | | | - Davide Pau
- SB Drug Discovery, West of Scotland Science Park, Glasgow G20 0XA, UK; (A.D.); (S.R.)
| | - David J. Stone
- Cerevel Therapeutics, 222 Jacobs St, Cambridge, MA 02141, USA; (J.L.); (M.F.T.); (D.J.S.); (J.J.R.)
| | - John J. Renger
- Cerevel Therapeutics, 222 Jacobs St, Cambridge, MA 02141, USA; (J.L.); (M.F.T.); (D.J.S.); (J.J.R.)
| | - Niels Fertig
- Nanion Technologies, Ganghoferstr. 70a, 80339 Munich, Germany (V.P.); (S.F.)
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7
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Lysak DH, Grisi M, Marable K, Conley GM, Michal CA, Moxley-Paquette V, Wolff WW, Downey K, Kock FVC, Costa PM, Ronda K, Moraes TB, Steiner K, Colnago LA, Simpson AJ. Exploring the Potential of Broadband Complementary Metal Oxide Semiconductor Micro-Coil Nuclear Magnetic Resonance for Environmental Research. Molecules 2023; 28:5080. [PMID: 37446742 PMCID: PMC10343494 DOI: 10.3390/molecules28135080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 06/23/2023] [Accepted: 06/27/2023] [Indexed: 07/15/2023] Open
Abstract
With sensitivity being the Achilles' heel of nuclear magnetic resonance (NMR), the superior mass sensitivity offered by micro-coils can be an excellent choice for tiny, mass limited samples such as eggs and small organisms. Recently, complementary metal oxide semiconductor (CMOS)-based micro-coil transceivers have been reported and demonstrate excellent mass sensitivity. However, the ability of broadband CMOS micro-coils to study heteronuclei has yet to be investigated, and here their potential is explored within the lens of environmental research. Eleven nuclei including 7Li, 19F, 31P and, 205Tl were studied and detection limits in the low to mid picomole range were found for an extended experiment. Further, two environmentally relevant samples (a sprouting broccoli seed and a D. magna egg) were successfully studied using the CMOS micro-coil system. 13C NMR was used to help resolve broad signals in the 1H spectrum of the 13C enriched broccoli seed, and steady state free precession was used to improve the signal-to-noise ratio by a factor of six. 19F NMR was used to track fluorinated contaminants in a single D. magna egg, showing potential for studying egg-pollutant interactions. Overall, CMOS micro-coil NMR demonstrates significant promise in environmental research, especially when the future potential to scale to multiple coil arrays (greatly improving throughput) is considered.
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Affiliation(s)
- Daniel H. Lysak
- Environmental NMR Centre, University of Toronto, Toronto, ON M1C 1A4, Canada
| | - Marco Grisi
- Annaida Technologies, Innovation Park, 1015 Lausanne, Switzerland
| | - Kathryn Marable
- Annaida Technologies, Innovation Park, 1015 Lausanne, Switzerland
| | | | - Carl A. Michal
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | | | - William W. Wolff
- Environmental NMR Centre, University of Toronto, Toronto, ON M1C 1A4, Canada
| | - Katelyn Downey
- Environmental NMR Centre, University of Toronto, Toronto, ON M1C 1A4, Canada
| | - Flavio V. C. Kock
- Environmental NMR Centre, University of Toronto, Toronto, ON M1C 1A4, Canada
| | - Peter M. Costa
- Environmental NMR Centre, University of Toronto, Toronto, ON M1C 1A4, Canada
| | - Kiera Ronda
- Environmental NMR Centre, University of Toronto, Toronto, ON M1C 1A4, Canada
| | - Tiago B. Moraes
- Departamento Engenharia de Biossistemas, Universidade de São Paulo/ESALQ, Av. Páduas Dias, 11, Piracicaba 13418-900, SP, Brazil
| | - Katrina Steiner
- Environmental NMR Centre, University of Toronto, Toronto, ON M1C 1A4, Canada
| | - Luiz A. Colnago
- Embrapa Instrumentação, Rua XV de Novembro 1452, São Carlos 13560-970, SP, Brazil
| | - Andre J. Simpson
- Environmental NMR Centre, University of Toronto, Toronto, ON M1C 1A4, Canada
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8
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Schroeter CB, Nelke C, Schewe M, Spohler L, Herrmann AM, Müntefering T, Huntemann N, Kuzikov M, Gribbon P, Albrecht S, Bock S, Hundehege P, Neelsen LC, Baukrowitz T, Seebohm G, Wünsch B, Bittner S, Ruck T, Budde T, Meuth SG. Validation of TREK1 ion channel activators as an immunomodulatory and neuroprotective strategy in neuroinflammation. Biol Chem 2023; 404:355-375. [PMID: 36774650 DOI: 10.1515/hsz-2022-0266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 01/16/2023] [Indexed: 02/13/2023]
Abstract
Modulation of two-pore domain potassium (K2P) channels has emerged as a novel field of therapeutic strategies as they may regulate immune cell activation and metabolism, inflammatory signals, or barrier integrity. One of these ion channels is the TWIK-related potassium channel 1 (TREK1). In the current study, we report the identification and validation of new TREK1 activators. Firstly, we used a modified potassium ion channel assay to perform high-throughput-screening of new TREK1 activators. Dose-response studies helped to identify compounds with a high separation between effectiveness and toxicity. Inside-out patch-clamp measurements of Xenopus laevis oocytes expressing TREK1 were used for further validation of these activators regarding specificity and activity. These approaches yielded three substances, E1, B3 and A2 that robustly activate TREK1. Functionally, we demonstrated that these compounds reduce levels of adhesion molecules on primary human brain and muscle endothelial cells without affecting cell viability. Finally, we studied compound A2 via voltage-clamp recordings as this activator displayed the strongest effect on adhesion molecules. Interestingly, A2 lacked TREK1 activation in the tested neuronal cell type. Taken together, this study provides data on novel TREK1 activators that might be employed to pharmacologically modulate TREK1 activity.
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Affiliation(s)
- Christina B Schroeter
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Christopher Nelke
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Marcus Schewe
- Institute of Physiology, Christian-Albrechts University Kiel, Hermann-Rodewald-Straße 5, 24118 Kiel, Germany
| | - Lucas Spohler
- Department of Neurology with Institute for Translational Neurology, University Hospital Münster, Albert-Schweitzer-Campus 1, D-48149 Münster, Germany
| | - Alexander M Herrmann
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Thomas Müntefering
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Niklas Huntemann
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Maria Kuzikov
- Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Schnackenburgallee 114, D-22525 Hamburg, Germany
- Fraunhofer Cluster of Excellence for Immune mediated diseases (CIMD), Theodor-Stern-Kai 7, D-60596 Frankfurt, Germany
| | - Philip Gribbon
- Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Schnackenburgallee 114, D-22525 Hamburg, Germany
- Fraunhofer Cluster of Excellence for Immune mediated diseases (CIMD), Theodor-Stern-Kai 7, D-60596 Frankfurt, Germany
| | - Sarah Albrecht
- Department of Neurology with Institute for Translational Neurology, University Hospital Münster, Albert-Schweitzer-Campus 1, D-48149 Münster, Germany
| | - Stefanie Bock
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Petra Hundehege
- Department of Neurology with Institute for Translational Neurology, University Hospital Münster, Albert-Schweitzer-Campus 1, D-48149 Münster, Germany
| | - Lea Christine Neelsen
- Institute of Physiology, Christian-Albrechts University Kiel, Hermann-Rodewald-Straße 5, 24118 Kiel, Germany
| | - Thomas Baukrowitz
- Institute of Physiology, Christian-Albrechts University Kiel, Hermann-Rodewald-Straße 5, 24118 Kiel, Germany
| | - Guiscard Seebohm
- IfGH-Cellular Electrophysiology, Department of Cardiology and Angiology, University Hospital of Münster, Albert-Schweitzer-Campus 1, D-48149 Münster, Germany
| | - Bernhard Wünsch
- Institute for Pharmaceutical and Medicinal Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, D-48149 Münster, Germany
| | - Stefan Bittner
- Department of Neurology, University Medical Center Mainz, Langenbeckstraße 1, D-55131 Mainz, Germany
| | - Tobias Ruck
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Thomas Budde
- Institute of Physiology I, University of Münster, Robert-Koch-Straße 27A, D-48149 Münster, Germany
| | - Sven G Meuth
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany
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Egbuna O, Zimmerman B, Manos G, Fortier A, Chirieac MC, Dakin LA, Friedman DJ, Bramham K, Campbell K, Knebelmann B, Barisoni L, Falk RJ, Gipson DS, Lipkowitz MS, Ojo A, Bunnage ME, Pollak MR, Altshuler D, Chertow GM. Inaxaplin for Proteinuric Kidney Disease in Persons with Two APOL1 Variants. N Engl J Med 2023; 388:969-979. [PMID: 36920755 DOI: 10.1056/nejmoa2202396] [Citation(s) in RCA: 47] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
BACKGROUND Persons with toxic gain-of-function variants in the gene encoding apolipoprotein L1 (APOL1) are at greater risk for the development of rapidly progressive, proteinuric nephropathy. Despite the known genetic cause, therapies targeting proteinuric kidney disease in persons with two APOL1 variants (G1 or G2) are lacking. METHODS We used tetracycline-inducible APOL1 human embryonic kidney (HEK293) cells to assess the ability of a small-molecule compound, inaxaplin, to inhibit APOL1 channel function. An APOL1 G2-homologous transgenic mouse model of proteinuric kidney disease was used to assess inaxaplin treatment for proteinuria. We then conducted a single-group, open-label, phase 2a clinical study in which inaxaplin was administered to participants who had two APOL1 variants, biopsy-proven focal segmental glomerulosclerosis, and proteinuria (urinary protein-to-creatinine ratio of ≥0.7 to <10 [with protein and creatinine both measured in grams] and an estimated glomerular filtration rate of ≥27 ml per minute per 1.73 m2 of body-surface area). Participants received inaxaplin daily for 13 weeks (15 mg for 2 weeks and 45 mg for 11 weeks) along with standard care. The primary outcome was the percent change from the baseline urinary protein-to-creatinine ratio at week 13 in participants who had at least 80% adherence to inaxaplin therapy. Safety was also assessed. RESULTS In preclinical studies, inaxaplin selectively inhibited APOL1 channel function in vitro and reduced proteinuria in the mouse model. Sixteen participants were enrolled in the phase 2a study. Among the 13 participants who were treated with inaxaplin and met the adherence threshold, the mean change from the baseline urinary protein-to-creatinine ratio at week 13 was -47.6% (95% confidence interval, -60.0 to -31.3). In an analysis that included all the participants regardless of adherence to inaxaplin therapy, reductions similar to those in the primary analysis were observed in all but 1 participant. Adverse events were mild or moderate in severity; none led to study discontinuation. CONCLUSIONS Targeted inhibition of APOL1 channel function with inaxaplin reduced proteinuria in participants with two APOL1 variants and focal segmental glomerulosclerosis. (Funded by Vertex Pharmaceuticals; VX19-147-101 ClinicalTrials.gov number, NCT04340362.).
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Affiliation(s)
- Ogo Egbuna
- From Vertex Pharmaceuticals (O.E., B.Z., G.M., A.F., M.C.C., L.A.D., M.E.B., D.A.), and Beth Israel Deaconess Medical Center, Harvard Medical School (D.J.F., M.R.P.) - both in Boston; King's College London, London (K.B.); Icahn School of Medicine at Mount Sinai, New York (K.C.); Necker Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris (B.K.); Duke University, Durham (L.B.), and the University of North Carolina at Chapel Hill, Chapel Hill (R.J.F.) - both in North Carolina; the University of Michigan, Ann Arbor (D.S.G.); Georgetown University Hospital, Washington, DC (M.S.L.); University of Kansas School of Medicine, Kansas City (A.O.); and Stanford University School of Medicine, Palo Alto, CA (G.M.C.)
| | - Brandon Zimmerman
- From Vertex Pharmaceuticals (O.E., B.Z., G.M., A.F., M.C.C., L.A.D., M.E.B., D.A.), and Beth Israel Deaconess Medical Center, Harvard Medical School (D.J.F., M.R.P.) - both in Boston; King's College London, London (K.B.); Icahn School of Medicine at Mount Sinai, New York (K.C.); Necker Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris (B.K.); Duke University, Durham (L.B.), and the University of North Carolina at Chapel Hill, Chapel Hill (R.J.F.) - both in North Carolina; the University of Michigan, Ann Arbor (D.S.G.); Georgetown University Hospital, Washington, DC (M.S.L.); University of Kansas School of Medicine, Kansas City (A.O.); and Stanford University School of Medicine, Palo Alto, CA (G.M.C.)
| | - George Manos
- From Vertex Pharmaceuticals (O.E., B.Z., G.M., A.F., M.C.C., L.A.D., M.E.B., D.A.), and Beth Israel Deaconess Medical Center, Harvard Medical School (D.J.F., M.R.P.) - both in Boston; King's College London, London (K.B.); Icahn School of Medicine at Mount Sinai, New York (K.C.); Necker Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris (B.K.); Duke University, Durham (L.B.), and the University of North Carolina at Chapel Hill, Chapel Hill (R.J.F.) - both in North Carolina; the University of Michigan, Ann Arbor (D.S.G.); Georgetown University Hospital, Washington, DC (M.S.L.); University of Kansas School of Medicine, Kansas City (A.O.); and Stanford University School of Medicine, Palo Alto, CA (G.M.C.)
| | - Anne Fortier
- From Vertex Pharmaceuticals (O.E., B.Z., G.M., A.F., M.C.C., L.A.D., M.E.B., D.A.), and Beth Israel Deaconess Medical Center, Harvard Medical School (D.J.F., M.R.P.) - both in Boston; King's College London, London (K.B.); Icahn School of Medicine at Mount Sinai, New York (K.C.); Necker Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris (B.K.); Duke University, Durham (L.B.), and the University of North Carolina at Chapel Hill, Chapel Hill (R.J.F.) - both in North Carolina; the University of Michigan, Ann Arbor (D.S.G.); Georgetown University Hospital, Washington, DC (M.S.L.); University of Kansas School of Medicine, Kansas City (A.O.); and Stanford University School of Medicine, Palo Alto, CA (G.M.C.)
| | - Madalina C Chirieac
- From Vertex Pharmaceuticals (O.E., B.Z., G.M., A.F., M.C.C., L.A.D., M.E.B., D.A.), and Beth Israel Deaconess Medical Center, Harvard Medical School (D.J.F., M.R.P.) - both in Boston; King's College London, London (K.B.); Icahn School of Medicine at Mount Sinai, New York (K.C.); Necker Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris (B.K.); Duke University, Durham (L.B.), and the University of North Carolina at Chapel Hill, Chapel Hill (R.J.F.) - both in North Carolina; the University of Michigan, Ann Arbor (D.S.G.); Georgetown University Hospital, Washington, DC (M.S.L.); University of Kansas School of Medicine, Kansas City (A.O.); and Stanford University School of Medicine, Palo Alto, CA (G.M.C.)
| | - Leslie A Dakin
- From Vertex Pharmaceuticals (O.E., B.Z., G.M., A.F., M.C.C., L.A.D., M.E.B., D.A.), and Beth Israel Deaconess Medical Center, Harvard Medical School (D.J.F., M.R.P.) - both in Boston; King's College London, London (K.B.); Icahn School of Medicine at Mount Sinai, New York (K.C.); Necker Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris (B.K.); Duke University, Durham (L.B.), and the University of North Carolina at Chapel Hill, Chapel Hill (R.J.F.) - both in North Carolina; the University of Michigan, Ann Arbor (D.S.G.); Georgetown University Hospital, Washington, DC (M.S.L.); University of Kansas School of Medicine, Kansas City (A.O.); and Stanford University School of Medicine, Palo Alto, CA (G.M.C.)
| | - David J Friedman
- From Vertex Pharmaceuticals (O.E., B.Z., G.M., A.F., M.C.C., L.A.D., M.E.B., D.A.), and Beth Israel Deaconess Medical Center, Harvard Medical School (D.J.F., M.R.P.) - both in Boston; King's College London, London (K.B.); Icahn School of Medicine at Mount Sinai, New York (K.C.); Necker Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris (B.K.); Duke University, Durham (L.B.), and the University of North Carolina at Chapel Hill, Chapel Hill (R.J.F.) - both in North Carolina; the University of Michigan, Ann Arbor (D.S.G.); Georgetown University Hospital, Washington, DC (M.S.L.); University of Kansas School of Medicine, Kansas City (A.O.); and Stanford University School of Medicine, Palo Alto, CA (G.M.C.)
| | - Kate Bramham
- From Vertex Pharmaceuticals (O.E., B.Z., G.M., A.F., M.C.C., L.A.D., M.E.B., D.A.), and Beth Israel Deaconess Medical Center, Harvard Medical School (D.J.F., M.R.P.) - both in Boston; King's College London, London (K.B.); Icahn School of Medicine at Mount Sinai, New York (K.C.); Necker Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris (B.K.); Duke University, Durham (L.B.), and the University of North Carolina at Chapel Hill, Chapel Hill (R.J.F.) - both in North Carolina; the University of Michigan, Ann Arbor (D.S.G.); Georgetown University Hospital, Washington, DC (M.S.L.); University of Kansas School of Medicine, Kansas City (A.O.); and Stanford University School of Medicine, Palo Alto, CA (G.M.C.)
| | - Kirk Campbell
- From Vertex Pharmaceuticals (O.E., B.Z., G.M., A.F., M.C.C., L.A.D., M.E.B., D.A.), and Beth Israel Deaconess Medical Center, Harvard Medical School (D.J.F., M.R.P.) - both in Boston; King's College London, London (K.B.); Icahn School of Medicine at Mount Sinai, New York (K.C.); Necker Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris (B.K.); Duke University, Durham (L.B.), and the University of North Carolina at Chapel Hill, Chapel Hill (R.J.F.) - both in North Carolina; the University of Michigan, Ann Arbor (D.S.G.); Georgetown University Hospital, Washington, DC (M.S.L.); University of Kansas School of Medicine, Kansas City (A.O.); and Stanford University School of Medicine, Palo Alto, CA (G.M.C.)
| | - Bertrand Knebelmann
- From Vertex Pharmaceuticals (O.E., B.Z., G.M., A.F., M.C.C., L.A.D., M.E.B., D.A.), and Beth Israel Deaconess Medical Center, Harvard Medical School (D.J.F., M.R.P.) - both in Boston; King's College London, London (K.B.); Icahn School of Medicine at Mount Sinai, New York (K.C.); Necker Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris (B.K.); Duke University, Durham (L.B.), and the University of North Carolina at Chapel Hill, Chapel Hill (R.J.F.) - both in North Carolina; the University of Michigan, Ann Arbor (D.S.G.); Georgetown University Hospital, Washington, DC (M.S.L.); University of Kansas School of Medicine, Kansas City (A.O.); and Stanford University School of Medicine, Palo Alto, CA (G.M.C.)
| | - Laura Barisoni
- From Vertex Pharmaceuticals (O.E., B.Z., G.M., A.F., M.C.C., L.A.D., M.E.B., D.A.), and Beth Israel Deaconess Medical Center, Harvard Medical School (D.J.F., M.R.P.) - both in Boston; King's College London, London (K.B.); Icahn School of Medicine at Mount Sinai, New York (K.C.); Necker Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris (B.K.); Duke University, Durham (L.B.), and the University of North Carolina at Chapel Hill, Chapel Hill (R.J.F.) - both in North Carolina; the University of Michigan, Ann Arbor (D.S.G.); Georgetown University Hospital, Washington, DC (M.S.L.); University of Kansas School of Medicine, Kansas City (A.O.); and Stanford University School of Medicine, Palo Alto, CA (G.M.C.)
| | - Ronald J Falk
- From Vertex Pharmaceuticals (O.E., B.Z., G.M., A.F., M.C.C., L.A.D., M.E.B., D.A.), and Beth Israel Deaconess Medical Center, Harvard Medical School (D.J.F., M.R.P.) - both in Boston; King's College London, London (K.B.); Icahn School of Medicine at Mount Sinai, New York (K.C.); Necker Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris (B.K.); Duke University, Durham (L.B.), and the University of North Carolina at Chapel Hill, Chapel Hill (R.J.F.) - both in North Carolina; the University of Michigan, Ann Arbor (D.S.G.); Georgetown University Hospital, Washington, DC (M.S.L.); University of Kansas School of Medicine, Kansas City (A.O.); and Stanford University School of Medicine, Palo Alto, CA (G.M.C.)
| | - Debbie S Gipson
- From Vertex Pharmaceuticals (O.E., B.Z., G.M., A.F., M.C.C., L.A.D., M.E.B., D.A.), and Beth Israel Deaconess Medical Center, Harvard Medical School (D.J.F., M.R.P.) - both in Boston; King's College London, London (K.B.); Icahn School of Medicine at Mount Sinai, New York (K.C.); Necker Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris (B.K.); Duke University, Durham (L.B.), and the University of North Carolina at Chapel Hill, Chapel Hill (R.J.F.) - both in North Carolina; the University of Michigan, Ann Arbor (D.S.G.); Georgetown University Hospital, Washington, DC (M.S.L.); University of Kansas School of Medicine, Kansas City (A.O.); and Stanford University School of Medicine, Palo Alto, CA (G.M.C.)
| | - Michael S Lipkowitz
- From Vertex Pharmaceuticals (O.E., B.Z., G.M., A.F., M.C.C., L.A.D., M.E.B., D.A.), and Beth Israel Deaconess Medical Center, Harvard Medical School (D.J.F., M.R.P.) - both in Boston; King's College London, London (K.B.); Icahn School of Medicine at Mount Sinai, New York (K.C.); Necker Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris (B.K.); Duke University, Durham (L.B.), and the University of North Carolina at Chapel Hill, Chapel Hill (R.J.F.) - both in North Carolina; the University of Michigan, Ann Arbor (D.S.G.); Georgetown University Hospital, Washington, DC (M.S.L.); University of Kansas School of Medicine, Kansas City (A.O.); and Stanford University School of Medicine, Palo Alto, CA (G.M.C.)
| | - Akinlolu Ojo
- From Vertex Pharmaceuticals (O.E., B.Z., G.M., A.F., M.C.C., L.A.D., M.E.B., D.A.), and Beth Israel Deaconess Medical Center, Harvard Medical School (D.J.F., M.R.P.) - both in Boston; King's College London, London (K.B.); Icahn School of Medicine at Mount Sinai, New York (K.C.); Necker Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris (B.K.); Duke University, Durham (L.B.), and the University of North Carolina at Chapel Hill, Chapel Hill (R.J.F.) - both in North Carolina; the University of Michigan, Ann Arbor (D.S.G.); Georgetown University Hospital, Washington, DC (M.S.L.); University of Kansas School of Medicine, Kansas City (A.O.); and Stanford University School of Medicine, Palo Alto, CA (G.M.C.)
| | - Mark E Bunnage
- From Vertex Pharmaceuticals (O.E., B.Z., G.M., A.F., M.C.C., L.A.D., M.E.B., D.A.), and Beth Israel Deaconess Medical Center, Harvard Medical School (D.J.F., M.R.P.) - both in Boston; King's College London, London (K.B.); Icahn School of Medicine at Mount Sinai, New York (K.C.); Necker Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris (B.K.); Duke University, Durham (L.B.), and the University of North Carolina at Chapel Hill, Chapel Hill (R.J.F.) - both in North Carolina; the University of Michigan, Ann Arbor (D.S.G.); Georgetown University Hospital, Washington, DC (M.S.L.); University of Kansas School of Medicine, Kansas City (A.O.); and Stanford University School of Medicine, Palo Alto, CA (G.M.C.)
| | - Martin R Pollak
- From Vertex Pharmaceuticals (O.E., B.Z., G.M., A.F., M.C.C., L.A.D., M.E.B., D.A.), and Beth Israel Deaconess Medical Center, Harvard Medical School (D.J.F., M.R.P.) - both in Boston; King's College London, London (K.B.); Icahn School of Medicine at Mount Sinai, New York (K.C.); Necker Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris (B.K.); Duke University, Durham (L.B.), and the University of North Carolina at Chapel Hill, Chapel Hill (R.J.F.) - both in North Carolina; the University of Michigan, Ann Arbor (D.S.G.); Georgetown University Hospital, Washington, DC (M.S.L.); University of Kansas School of Medicine, Kansas City (A.O.); and Stanford University School of Medicine, Palo Alto, CA (G.M.C.)
| | - David Altshuler
- From Vertex Pharmaceuticals (O.E., B.Z., G.M., A.F., M.C.C., L.A.D., M.E.B., D.A.), and Beth Israel Deaconess Medical Center, Harvard Medical School (D.J.F., M.R.P.) - both in Boston; King's College London, London (K.B.); Icahn School of Medicine at Mount Sinai, New York (K.C.); Necker Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris (B.K.); Duke University, Durham (L.B.), and the University of North Carolina at Chapel Hill, Chapel Hill (R.J.F.) - both in North Carolina; the University of Michigan, Ann Arbor (D.S.G.); Georgetown University Hospital, Washington, DC (M.S.L.); University of Kansas School of Medicine, Kansas City (A.O.); and Stanford University School of Medicine, Palo Alto, CA (G.M.C.)
| | - Glenn M Chertow
- From Vertex Pharmaceuticals (O.E., B.Z., G.M., A.F., M.C.C., L.A.D., M.E.B., D.A.), and Beth Israel Deaconess Medical Center, Harvard Medical School (D.J.F., M.R.P.) - both in Boston; King's College London, London (K.B.); Icahn School of Medicine at Mount Sinai, New York (K.C.); Necker Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris (B.K.); Duke University, Durham (L.B.), and the University of North Carolina at Chapel Hill, Chapel Hill (R.J.F.) - both in North Carolina; the University of Michigan, Ann Arbor (D.S.G.); Georgetown University Hospital, Washington, DC (M.S.L.); University of Kansas School of Medicine, Kansas City (A.O.); and Stanford University School of Medicine, Palo Alto, CA (G.M.C.)
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10
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Bartz FM, Beirow K, Wurm K, Baecker D, Link A, Bednarski PJ. A graphite furnace-atomic absorption spectrometry-based rubidium efflux assay for screening activators of the K v 7.2/3 channel. Arch Pharm (Weinheim) 2023; 356:e2200585. [PMID: 36748851 DOI: 10.1002/ardp.202200585] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/21/2022] [Accepted: 01/18/2023] [Indexed: 02/08/2023]
Abstract
For the characterization of Kv 7.2/3 channel activators, several analytical methods are available that vary in effort and cost. In addition to the technically elaborate patch-clamp method, which serves as a reference method, there exist several medium to high-throughput screening methods including a rubidium efflux flame-atomic absorption spectrometry (F-AAS) assay and a commercial thallium uptake fluorescence-based assay. In this study, the general suitability of a graphite furnace atomic absorption spectrometry (GF-AAS)-based rubidium efflux assay as a screening method for Kv 7.2/3 channel activators was demonstrated. With flupirtine serving as a reference compound, 16 newly synthesizedcompounds and the known Kv 7.2/3 activator retigabine were first classified as either active or inactive by using the GF-AAS-based rubidium (Rb) efflux assay. Then, the results were compared with a thallium (Tl) uptake fluorescence-based fluorometric imaging plate reader (FLIPR) potassium assay. Overall, 16 of 17 compounds were classified by the GF-AAS-based assay in agreement with their channel-activating properties determined by the more expensive Tl uptake, fluorescence-based assay. Thus, the performance of the GF-AAS-based Rb assay for primary drug screening of Kv 7.2/3-activating compounds was clearly demonstrated, as documented by the calculated Z'-factor of the GF-AAS-based method. Moreover, method development included optimization of the coating of the microtiter plates and the washing procedure, which extended the range of this assay to poorly adherent cells such as the HEK293 cells used in this study.
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Affiliation(s)
- Frieda-Marie Bartz
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| | - Kristin Beirow
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| | - Konrad Wurm
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| | - Daniel Baecker
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| | - Andreas Link
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| | - Patrick J Bednarski
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
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11
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Srinivasan SR. Targeting Circuit Abnormalities in Neurodegenerative Disease. Mol Pharmacol 2023; 103:38-44. [PMID: 36310030 DOI: 10.1124/molpharm.122.000563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 10/18/2022] [Accepted: 10/24/2022] [Indexed: 02/03/2023] Open
Abstract
Despite significant improvement in our ability to diagnose both common and rare neurodegenerative diseases and understand their underlying biologic mechanisms, there remains a disproportionate lack of effective treatments, reflecting the complexity of these disorders. Successfully advancing novel treatments for neurodegenerative disorders will require reconsideration of traditional approaches, which to date have focused largely on specific disease proteins or cells of origin. This article proposes reframing these diseases as conditions of dysfunctional circuitry as a complement to ongoing efforts. Specifically reviewed is how aberrant spiking is a common downstream mechanism in numerous neurodegenerative diseases, often driven by dysfunction in specific ion channels. Surgical modification of this electrical activity via deep brain stimulation is already an approved modality for many of these disorders. Therefore, restoring proper electrical activity by targeting these channels pharmacologically represents a viable strategy for intervention, not only for symptomatic management but also as a potential disease-modifying therapy. Such an approach is likely to be a promising route to treating these devastating disorders, either as monotherapy or in conjunction with current drugs. SIGNIFICANCE STATEMENT: Despite extensive research and improved understanding of the biology driving neurodegenerative disease, there has not been a concomitant increase in approved therapies. Accordingly, it is time to shift our perspective and recognize these diseases also as disorders of circuitry to further yield novel drug targets and new interventions. An approach focused on treating dysfunctional circuitry has the potential to reduce or reverse patient symptoms and potentially modify disease course.
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12
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Melnikov F, Anger LT, Hasselgren C. Toward Quantitative Models in Safety Assessment: A Case Study to Show Impact of Dose-Response Inference on hERG Inhibition Models. Int J Mol Sci 2022; 24:ijms24010635. [PMID: 36614078 PMCID: PMC9820331 DOI: 10.3390/ijms24010635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/23/2022] [Accepted: 12/24/2022] [Indexed: 12/31/2022] Open
Abstract
Due to challenges with historical data and the diversity of assay formats, in silico models for safety-related endpoints are often based on discretized data instead of the data on a natural continuous scale. Models for discretized endpoints have limitations in usage and interpretation that can impact compound design. Here, we present a consistent data inference approach, exemplified on two data sets of Ether-à-go-go-Related Gene (hERG) K+ inhibition data, for dose-response and screening experiments that are generally applicable for in vitro assays. hERG inhibition has been associated with severe cardiac effects and is one of the more prominent safety targets assessed in drug development, using a wide array of in vitro and in silico screening methods. In this study, the IC50 for hERG inhibition is estimated from diverse historical proprietary data. The IC50 derived from a two-point proprietary screening data set demonstrated high correlation (R = 0.98, MAE = 0.08) with IC50s derived from six-point dose-response curves. Similar IC50 estimation accuracy was obtained on a public thallium flux assay data set (R = 0.90, MAE = 0.2). The IC50 data were used to develop a robust quantitative model. The model's MAE (0.47) and R2 (0.46) were on par with literature statistics and approached assay reproducibility. Using a continuous model has high value for pharmaceutical projects, as it enables rank ordering of compounds and evaluation of compounds against project-specific inhibition thresholds. This data inference approach can be widely applicable to assays with quantitative readouts and has the potential to impact experimental design and improve model performance, interpretation, and acceptance across many standard safety endpoints.
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13
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Inhibition of SARS-CoV-2 Viral Channel Activity Using FDA-Approved Channel Modulators Independent of Variants. Biomolecules 2022; 12:biom12111673. [PMID: 36421688 PMCID: PMC9687591 DOI: 10.3390/biom12111673] [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: 10/04/2022] [Revised: 10/29/2022] [Accepted: 11/07/2022] [Indexed: 11/16/2022] Open
Abstract
Background: SARS-CoV-2 has undergone mutations, yielding clinically relevant variants. Hypothesis: We hypothesized that in SARS-CoV-2, two highly conserved Orf3a and E channels directly related to the virus replication were a target for the detection and inhibition of the viral replication, independent of the variant, using FDA-approved ion channel modulators. Methods: A combination of a fluorescence potassium ion assay with channel modulators was developed to detect SARS-CoV-2 Orf3a/E channel activity. Two FDA-approved drugs, amantadine (an antiviral) and amitriptyline (an antidepressant), which are ion channel blockers, were tested as to whether they inhibited Orf3a/E channel activity in isolated virus variants and in nasal swab samples from COVID-19 patients. The variants were confirmed by PCR sequencing. Results: In isolated SARS-CoV-2 Alpha, Beta, and Delta variants, the channel activity of Orf3a/E was detected and inhibited by emodin and gliclazide (IC50 = 0.42 mM). In the Delta swab samples, amitriptyline and amantadine inhibited the channel activity of viral proteins, with IC50 values of 0.73 mM and 1.11 mM, respectively. In the Omicron swab samples, amitriptyline inhibited the channel activity, with an IC50 of 0.76 mM. Conclusions: We developed an efficient method to screen FDA-approved ion channel modulators that could be repurposed to detect and inhibit SARS-CoV-2 viral replication, independent of variants.
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14
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Musella S, Carotenuto L, Iraci N, Baroli G, Ciaglia T, Nappi P, Basilicata MG, Salviati E, Barrese V, Vestuto V, Pignataro G, Pepe G, Sommella E, Di Sarno V, Manfra M, Campiglia P, Gomez-Monterrey I, Bertamino A, Taglialatela M, Ostacolo C, Miceli F. Beyond Retigabine: Design, Synthesis, and Pharmacological Characterization of a Potent and Chemically Stable Neuronal Kv7 Channel Activator with Anticonvulsant Activity. J Med Chem 2022; 65:11340-11364. [PMID: 35972998 PMCID: PMC9421656 DOI: 10.1021/acs.jmedchem.2c00911] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
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Neuronal Kv7 channels represent important pharmacological
targets
for hyperexcitability disorders including epilepsy. Retigabine is
the prototype Kv7 activator clinically approved for seizure treatment;
however, severe side effects associated with long-term use have led
to its market discontinuation. Building upon the recently described
cryoEM structure of Kv7.2 complexed with retigabine and on previous
structure–activity relationship studies, a small library of
retigabine analogues has been designed, synthesized, and characterized
for their Kv7 opening ability using both fluorescence- and electrophysiology-based
assays. Among all tested compounds, 60 emerged as a potent
and photochemically stable neuronal Kv7 channel activator. Compared
to retigabine, compound 60 displayed a higher brain/plasma
distribution ratio, a longer elimination half-life, and more potent
and effective anticonvulsant effects in an acute seizure model in
mice. Collectively, these data highlight compound 60 as
a promising lead compound for the development of novel Kv7 activators
for the treatment of hyperexcitability diseases.
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Affiliation(s)
- Simona Musella
- Department of Pharmacy, University of Salerno, Via G. Paolo II 132, Fisciano 84084, Salerno, Italy
| | - Lidia Carotenuto
- Department of Neuroscience, Reproductive Sciences and Dentistry, University Federico II of Naples, Via Pansini, 5, Naples 80131, Italy
| | - Nunzio Iraci
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences (CHIBIOFARAM), University of Messina, Viale Ferdinando Stagno d'Alcontres 31, Messina 98166, Italy
| | - Giulia Baroli
- Department of Neuroscience, Reproductive Sciences and Dentistry, University Federico II of Naples, Via Pansini, 5, Naples 80131, Italy
| | - Tania Ciaglia
- Department of Pharmacy, University of Salerno, Via G. Paolo II 132, Fisciano 84084, Salerno, Italy
| | - Piera Nappi
- Department of Neuroscience, Reproductive Sciences and Dentistry, University Federico II of Naples, Via Pansini, 5, Naples 80131, Italy
| | | | - Emanuela Salviati
- Department of Pharmacy, University of Salerno, Via G. Paolo II 132, Fisciano 84084, Salerno, Italy
| | - Vincenzo Barrese
- Department of Neuroscience, Reproductive Sciences and Dentistry, University Federico II of Naples, Via Pansini, 5, Naples 80131, Italy
| | - Vincenzo Vestuto
- Department of Pharmacy, University of Salerno, Via G. Paolo II 132, Fisciano 84084, Salerno, Italy
| | - Giuseppe Pignataro
- Department of Neuroscience, Reproductive Sciences and Dentistry, University Federico II of Naples, Via Pansini, 5, Naples 80131, Italy
| | - Giacomo Pepe
- Department of Pharmacy, University of Salerno, Via G. Paolo II 132, Fisciano 84084, Salerno, Italy
| | - Eduardo Sommella
- Department of Pharmacy, University of Salerno, Via G. Paolo II 132, Fisciano 84084, Salerno, Italy
| | - Veronica Di Sarno
- Department of Pharmacy, University of Salerno, Via G. Paolo II 132, Fisciano 84084, Salerno, Italy
| | - Michele Manfra
- Department of Science, University of Basilicata, Via dell'Ateneo Lucano 10, Potenza 85100, Italy
| | - Pietro Campiglia
- Department of Pharmacy, University of Salerno, Via G. Paolo II 132, Fisciano 84084, Salerno, Italy
| | - Isabel Gomez-Monterrey
- Department of Pharmacy, University Federico II of Naples, Via D. Montesano 49, Naples 80131, Italy
| | - Alessia Bertamino
- Department of Pharmacy, University of Salerno, Via G. Paolo II 132, Fisciano 84084, Salerno, Italy
| | - Maurizio Taglialatela
- Department of Neuroscience, Reproductive Sciences and Dentistry, University Federico II of Naples, Via Pansini, 5, Naples 80131, Italy
| | - Carmine Ostacolo
- Department of Pharmacy, University Federico II of Naples, Via D. Montesano 49, Naples 80131, Italy
| | - Francesco Miceli
- Department of Neuroscience, Reproductive Sciences and Dentistry, University Federico II of Naples, Via Pansini, 5, Naples 80131, Italy
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15
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Joshi P, Patel R, Kang SY, Serbinowski E, Lee MY. Establishment of ion channel and ABC transporter assays in 3D-cultured ReNcell VM on a 384-pillar plate for neurotoxicity potential. Toxicol In Vitro 2022; 82:105375. [PMID: 35550413 DOI: 10.1016/j.tiv.2022.105375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 04/05/2022] [Accepted: 05/03/2022] [Indexed: 10/18/2022]
Abstract
Neurotoxicity potential of compounds by inhibition of ion channels and efflux transporters has been studied traditionally using two-dimensionally (2D) cultured cell lines such as CHO and HEK-293 overexpressing the protein of interest. However, these approaches are time consuming and do not recapitulate the activity of ion channels and efflux transporters indigenously expressed in neural stem cells (NSCs) in vivo. To overcome these issues, we established ion channel and transporter assays on a 384-pillar plate with three-dimensionally (3D) cultured ReNcell VM and demonstrated high-throughput measurement of ion channel and transporter activity. RNA sequencing analysis identified major ion channels and efflux transporters expressed in ReNcell VM, followed by validating 3D ReNcell-based ion channel and transporter assays with model compounds. Major ion channel activities were measured by specifically inhibiting potassium channels Kv 7.2 with XE-991 and Kv 4.3 with fluoxetine, and a calcium channel with 2-APB. Activities of major efflux transporters, MDR1, MRP1, and BCRP, were assessed using their respective blockers, verapamil, probenecid, and novobiocin. From this study, we demonstrated that 3D-cultured ReNcell VM on the 384-pillar plate could be a good alternative to rapidly identify environmental chemicals and therapeutic compounds for their role in modulating the activity of ion channels and efflux transporters, potentially leading to neurotoxicity.
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Affiliation(s)
- Pranav Joshi
- Department of Chemical and Biomedical Engineering, Cleveland State University, Cleveland, OH, USA; Bioprinting Laboratories Inc, Denton, TX, USA
| | - Rushabh Patel
- Department of Chemical and Biomedical Engineering, Cleveland State University, Cleveland, OH, USA; College of Medicine and Life Sciences, University of Toledo, Toledo, OH, USA
| | - Soo-Yeon Kang
- Department of Chemical and Biomedical Engineering, Cleveland State University, Cleveland, OH, USA; Department of Biomedical Engineering, University of North Texas, Denton, TX, USA
| | - Emily Serbinowski
- Department of Chemical and Biomedical Engineering, Cleveland State University, Cleveland, OH, USA; College of Medicine and Life Sciences, University of Toledo, Toledo, OH, USA
| | - Moo-Yeal Lee
- Department of Chemical and Biomedical Engineering, Cleveland State University, Cleveland, OH, USA; Department of Biomedical Engineering, University of North Texas, Denton, TX, USA.
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16
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Srinivasan SR, Huang H, Chang WC, Nasburg JA, Nguyen HM, Strassmaier T, Wulff H, Shakkottai VG. Discovery of Novel Activators of Large-Conductance Calcium-Activated Potassium Channels for the Treatment of Cerebellar Ataxia. Mol Pharmacol 2022; 102:438-449. [PMID: 35489717 PMCID: PMC9341255 DOI: 10.1124/molpharm.121.000478] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 04/07/2022] [Indexed: 01/11/2023] Open
Abstract
Impaired cerebellar Purkinje neuron firing resulting from reduced expression of large-conductance calcium-activated potassium (BK) channels is a consistent feature in models of inherited neurodegenerative spinocerebellar ataxia (SCA). Restoring BK channel expression improves motor function and delays cerebellar degeneration, indicating that BK channels are an attractive therapeutic target. Current BK channel activators lack specificity and potency and are therefore poor templates for future drug development. We implemented an automated patch clamp platform for high-throughput drug discovery of BK channel activators using the Nanion SyncroPatch 384PE system. We screened over 15,000 compounds for their ability to increase BK channel current amplitude under conditions of lower intracellular calcium that is present in disease. We identified several novel BK channel activators that were then retested on the SyncroPatch 384PE to generate concentration-response curves (CRCs). Compounds with favorable CRCs were subsequently tested for their ability to improve irregular cerebellar Purkinje neuron spiking, characteristic of BK channel dysfunction in SCA1 mice. We identified a novel BK channel activator, 4-chloro-N-(5-chloro-2-cyanophenyl)-3-(trifluoromethyl)benzene-1-sulfonamide (herein renamed BK-20), that exhibited a more potent half-maximal activation of BK current (pAC50 = 4.64) than NS-1619 (pAC50 = 3.7) at a free internal calcium concentration of 270 nM in a heterologous expression system and improved spiking regularity in SCA1 Purkinje neurons. BK-20 had no activity on small-conductance calcium-activated potassium (SK)1-3 channels but interestingly was a potent blocker of the T-type calcium channel, Cav3.1 (IC50 = 1.05 μM). Our work describes both a novel compound for further drug development in disorders with irregular Purkinje spiking and a unique platform for drug discovery in degenerative ataxias. SIGNIFICANCE STATEMENT: Motor impairment associated with altered Purkinje cell spiking due to dysregulation of large-conductance calcium-activated potassium (BK) channel expression and function is a shared feature of disease in many degenerative ataxias. BK channel activators represent an outstanding therapeutic agent for ataxia. We have developed a high-throughput platform to screen for BK channel activators and identified a novel compound that can serve as a template for future drug development for the treatment of these disabling disorders.
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Affiliation(s)
- Sharan R Srinivasan
- Brigham and Women's Hospital, Department of Neurology, Boston, Massachusetts (S.R.S.); University of Texas Southwestern Medical Center, Department of Neurology, Dallas, Texas (H.H., V.G.S.); University of Michigan, Department of Neurology, Ann Arbor, Michigan (S.R.S., W.-C.C.); University of California, Davis, Department of Pharmacology, Davis, California (J.A.N., H.M.N., H.W.); and Nanion Technologies, Munich, Germany (T.S.)
| | - Haoran Huang
- Brigham and Women's Hospital, Department of Neurology, Boston, Massachusetts (S.R.S.); University of Texas Southwestern Medical Center, Department of Neurology, Dallas, Texas (H.H., V.G.S.); University of Michigan, Department of Neurology, Ann Arbor, Michigan (S.R.S., W.-C.C.); University of California, Davis, Department of Pharmacology, Davis, California (J.A.N., H.M.N., H.W.); and Nanion Technologies, Munich, Germany (T.S.)
| | - Wei-Chih Chang
- Brigham and Women's Hospital, Department of Neurology, Boston, Massachusetts (S.R.S.); University of Texas Southwestern Medical Center, Department of Neurology, Dallas, Texas (H.H., V.G.S.); University of Michigan, Department of Neurology, Ann Arbor, Michigan (S.R.S., W.-C.C.); University of California, Davis, Department of Pharmacology, Davis, California (J.A.N., H.M.N., H.W.); and Nanion Technologies, Munich, Germany (T.S.)
| | - Joshua A Nasburg
- Brigham and Women's Hospital, Department of Neurology, Boston, Massachusetts (S.R.S.); University of Texas Southwestern Medical Center, Department of Neurology, Dallas, Texas (H.H., V.G.S.); University of Michigan, Department of Neurology, Ann Arbor, Michigan (S.R.S., W.-C.C.); University of California, Davis, Department of Pharmacology, Davis, California (J.A.N., H.M.N., H.W.); and Nanion Technologies, Munich, Germany (T.S.)
| | - Hai M Nguyen
- Brigham and Women's Hospital, Department of Neurology, Boston, Massachusetts (S.R.S.); University of Texas Southwestern Medical Center, Department of Neurology, Dallas, Texas (H.H., V.G.S.); University of Michigan, Department of Neurology, Ann Arbor, Michigan (S.R.S., W.-C.C.); University of California, Davis, Department of Pharmacology, Davis, California (J.A.N., H.M.N., H.W.); and Nanion Technologies, Munich, Germany (T.S.)
| | - Tim Strassmaier
- Brigham and Women's Hospital, Department of Neurology, Boston, Massachusetts (S.R.S.); University of Texas Southwestern Medical Center, Department of Neurology, Dallas, Texas (H.H., V.G.S.); University of Michigan, Department of Neurology, Ann Arbor, Michigan (S.R.S., W.-C.C.); University of California, Davis, Department of Pharmacology, Davis, California (J.A.N., H.M.N., H.W.); and Nanion Technologies, Munich, Germany (T.S.)
| | - Heike Wulff
- Brigham and Women's Hospital, Department of Neurology, Boston, Massachusetts (S.R.S.); University of Texas Southwestern Medical Center, Department of Neurology, Dallas, Texas (H.H., V.G.S.); University of Michigan, Department of Neurology, Ann Arbor, Michigan (S.R.S., W.-C.C.); University of California, Davis, Department of Pharmacology, Davis, California (J.A.N., H.M.N., H.W.); and Nanion Technologies, Munich, Germany (T.S.)
| | - Vikram G Shakkottai
- Brigham and Women's Hospital, Department of Neurology, Boston, Massachusetts (S.R.S.); University of Texas Southwestern Medical Center, Department of Neurology, Dallas, Texas (H.H., V.G.S.); University of Michigan, Department of Neurology, Ann Arbor, Michigan (S.R.S., W.-C.C.); University of California, Davis, Department of Pharmacology, Davis, California (J.A.N., H.M.N., H.W.); and Nanion Technologies, Munich, Germany (T.S.)
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17
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Prael III FJ, Kim K, Du Y, Spitznagel BD, Sulikowski GA, Delpire E, Weaver CD. Discovery of Small Molecule KCC2 Potentiators Which Attenuate In Vitro Seizure-Like Activity in Cultured Neurons. Front Cell Dev Biol 2022; 10:912812. [PMID: 35813195 PMCID: PMC9263442 DOI: 10.3389/fcell.2022.912812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 06/02/2022] [Indexed: 01/14/2023] Open
Abstract
KCC2 is a K+-Cl- cotransporter that is expressed in neurons throughout the central nervous system. Deficits in KCC2 activity have been implicated in a variety of neurological disorders, including epilepsy, chronic pain, autism spectrum disorders, and Rett syndrome. Therefore, it has been hypothesized that pharmacological potentiation of KCC2 activity could provide a treatment for these disorders. To evaluate the therapeutic potential of pharmacological KCC2 potentiation, drug-like, selective KCC2 potentiators are required. Unfortunately, the lack of such tools has greatly hampered the investigation of the KCC2 potentiation hypothesis. Herein, we describe the discovery and characterization of a new class of small-molecule KCC2 potentiator. This newly discovered class exhibits KCC2-dependent activity and a unique mechanistic profile relative to previously reported small molecules. Furthermore, we demonstrate that KCC2 potentiation by this new class of KCC2 potentiator attenuates seizure-like activity in neuronal-glial co-cultures. Together, our results provide evidence that pharmacological KCC2 potentiation, by itself, is sufficient to attenuate neuronal excitability in an in vitro model that is sensitive to anti-epileptic drugs. Our findings and chemical tools are important for evaluating the promise of KCC2 as a therapeutic target and could lay a foundation for the development of KCC2-directed therapeutics for multiple neurological disorders.
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Affiliation(s)
- Francis J. Prael III
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States,Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, United States
| | - Kwangho Kim
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, United States,Department of Chemistry, Vanderbilt University, Nashville, TN, United States
| | - Yu Du
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States
| | | | - Gary A. Sulikowski
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States,Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, United States,Department of Chemistry, Vanderbilt University, Nashville, TN, United States
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - C. David Weaver
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States,Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, United States,Department of Chemistry, Vanderbilt University, Nashville, TN, United States,*Correspondence: C. David Weaver,
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18
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Egly CL, Blackwell DJ, Schmeckpeper J, Delisle BP, Weaver CD, Knollmann BC. A High-Throughput Screening Assay to Identify Drugs that Can Treat Long QT Syndrome Caused by Trafficking-Deficient K V11.1 (hERG) Variants. Mol Pharmacol 2022; 101:236-245. [PMID: 35125346 PMCID: PMC9638947 DOI: 10.1124/molpharm.121.000421] [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: 10/04/2021] [Accepted: 01/01/2022] [Indexed: 11/22/2022] Open
Abstract
Loss-of-function (LOF) variants in the KV11.1 potassium channel cause long QT syndrome (LQTS). Most variants disrupt intracellular channel transport (trafficking) to the cell membrane. Since some channel inhibitors improve trafficking of KV11.1 variants, a high-throughput screening (HTS) assay to detect trafficking enhancement would be valuable to the identification of drug candidates. The thallium (Tl+) flux assay technique, widely used for drug screening, was optimized using human embryonic kidney (HEK-293) cells expressing a trafficking-deficient KV11.1 variant in 384-well plates. Assay quality was assessed using Z prime (Z') scores comparing vehicle to E-4031, a drug that increases KV11.1 membrane trafficking. The optimized assay was validated by immunoblot, electrophysiology experiments, and a pilot drug screen. The combination of: 1) truncating the trafficking-deficient variant KV11.1-G601S (KV11.1-G601S-G965*X) with the addition of 2) KV11.1 channel activator (VU0405601) and 3) cesium (Cs+) to the Tl+ flux assay buffer resulted in an outstanding Z' of 0.83. To validate the optimized trafficking assay, we carried out a pilot screen that identified three drugs (ibutilide, azaperone, and azelastine) that increase KV11.1 trafficking. The new assay exhibited 100% sensitivity and specificity. Immunoblot and voltage-clamp experiments confirmed that all three drugs identified by the new assay improved membrane trafficking of two additional LQTS KV11.1 variants. We report two new ways to increase target-specific activity in trafficking assays-genetic modification and channel activation-that yielded a novel HTS assay for identifying drugs that improve membrane expression of pathogenic KV11.1 variants. SIGNIFICANCE STATEMENT: This manuscript reports the development of a high-throughput assay (thallium flux) to identify drugs that can increase function in KV11.1 variants that are trafficking-deficient. Two key aspects that improved the resolving power of the assay and could be transferable to other ion channel trafficking-related assays include genetic modification and channel activation.
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Affiliation(s)
- Christian L Egly
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee (C.L.E., D.J.B., J.S., B.C.K.); Department of Physiology, University of Kentucky, Lexington, Kentucky (B.P.D.); and Department of Pharmacology, Vanderbilt University, Nashville, Tennessee (C.D.W.)
| | - Daniel J Blackwell
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee (C.L.E., D.J.B., J.S., B.C.K.); Department of Physiology, University of Kentucky, Lexington, Kentucky (B.P.D.); and Department of Pharmacology, Vanderbilt University, Nashville, Tennessee (C.D.W.)
| | - Jeffrey Schmeckpeper
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee (C.L.E., D.J.B., J.S., B.C.K.); Department of Physiology, University of Kentucky, Lexington, Kentucky (B.P.D.); and Department of Pharmacology, Vanderbilt University, Nashville, Tennessee (C.D.W.)
| | - Brian P Delisle
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee (C.L.E., D.J.B., J.S., B.C.K.); Department of Physiology, University of Kentucky, Lexington, Kentucky (B.P.D.); and Department of Pharmacology, Vanderbilt University, Nashville, Tennessee (C.D.W.)
| | - C David Weaver
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee (C.L.E., D.J.B., J.S., B.C.K.); Department of Physiology, University of Kentucky, Lexington, Kentucky (B.P.D.); and Department of Pharmacology, Vanderbilt University, Nashville, Tennessee (C.D.W.)
| | - Björn C Knollmann
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee (C.L.E., D.J.B., J.S., B.C.K.); Department of Physiology, University of Kentucky, Lexington, Kentucky (B.P.D.); and Department of Pharmacology, Vanderbilt University, Nashville, Tennessee (C.D.W.)
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19
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Tsentsevitsky AN, Khaziev EF, Kovyazina IV, Petrov AM. GIRK channel as a versatile regulator of neurotransmitter release via L-type Ca 2+ channel-dependent mechanism in the neuromuscular junction. Neuropharmacology 2022; 209:109021. [PMID: 35245509 DOI: 10.1016/j.neuropharm.2022.109021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 02/14/2022] [Accepted: 02/25/2022] [Indexed: 01/04/2023]
Abstract
G protein-gated inwardly rectifying potassium (GIRK) channels are one of the main regulators of neuronal excitability. Activation of GIRK channels in the CNS usually leads to postsynaptic inhibition. However, the function of GIRK channels in the presynaptic processes, notably neurotransmitter release form motor nerve terminals, is yet to be comprehensively understood. Here, using electrophysiological and fluorescent approaches, the role of GIRK channels in neurotransmitter release from frog motor nerve terminals was studied. We found that the inhibition of GIRK channels with nanomolar tertiapin-Q synchronized exocytosis events with action potential but suppressed spontaneous and evoked neurotransmitter release, as well as Ca2+ transient and membrane permeability for K+. The action of GIRK channel inhibition on evoked neurotransmission was prevented by selective antagonist of voltage-gated Ca2+ channels of L-type. Furthermore, the effects of muscarinic acetylcholine receptor activation on neurotransmitter release, Ca2+ transient and K+ channel activity were markedly modulated by inhibition of GIRK channels. Thus, at the motor nerve terminals GIRK channels can regulate timing of neurotransmitter release and be a positive modulator of synaptic vesicle exocytosis acting partially via L-type Ca2+ channels. In addition, GIRK channels are key players in a feedback control of neurotransmitter release by muscarinic acetylcholine receptors.
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Affiliation(s)
- Andrei N Tsentsevitsky
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC "Kazan Scientific Center of RAS", P.o. Box 30, 420111, Kazan, Russia
| | - Eduard F Khaziev
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC "Kazan Scientific Center of RAS", P.o. Box 30, 420111, Kazan, Russia
| | - Irina V Kovyazina
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC "Kazan Scientific Center of RAS", P.o. Box 30, 420111, Kazan, Russia; Kazan State Medical University, Butlerov St., 49, 420008, Kazan, Russia.
| | - Alexey M Petrov
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC "Kazan Scientific Center of RAS", P.o. Box 30, 420111, Kazan, Russia; Kazan State Medical University, Butlerov St., 49, 420008, Kazan, Russia
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20
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Role of Skin Stretch on Local Vascular Permeability in Murine and Cell Culture Models. Plast Reconstr Surg Glob Open 2022; 10:e4084. [PMID: 35186636 PMCID: PMC8849308 DOI: 10.1097/gox.0000000000004084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 11/29/2021] [Indexed: 01/15/2023]
Abstract
Excessive mechanical forces, particularly skin stretch, have been implicated in pathological cutaneous scarring. We hypothesize that this reflects, in part, stretch-induced vessel leakage that provokes prolonged wound/scar inflammation. However, this has never been observed directly. Here, a mouse model was used to examine the effect of skin flap stretching on vascular permeability. An in vitro model with pseudocapillaries grown in a stretchable chamber was also used to determine the effect of stretching on endothelial cell morphology and ion channel activity.
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21
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Methods of Measuring Mitochondrial Potassium Channels: A Critical Assessment. Int J Mol Sci 2022; 23:ijms23031210. [PMID: 35163132 PMCID: PMC8835872 DOI: 10.3390/ijms23031210] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 12/22/2022] Open
Abstract
In this paper, the techniques used to study the function of mitochondrial potassium channels are critically reviewed. The majority of these techniques have been known for many years as a result of research on plasma membrane ion channels. Hence, in this review, we focus on the critical evaluation of techniques used in the studies of mitochondrial potassium channels, describing their advantages and limitations. Functional analysis of mitochondrial potassium channels in comparison to that of plasmalemmal channels presents additional experimental challenges. The reliability of functional studies of mitochondrial potassium channels is often affected by the need to isolate mitochondria and by functional properties of mitochondria such as respiration, metabolic activity, swelling capacity, or high electrical potential. Three types of techniques are critically evaluated: electrophysiological techniques, potassium flux measurements, and biochemical techniques related to potassium flux measurements. Finally, new possible approaches to the study of the function of mitochondrial potassium channels are presented. We hope that this review will assist researchers in selecting reliable methods for studying, e.g., the effects of drugs on mitochondrial potassium channel function. Additionally, this review should aid in the critical evaluation of the results reported in various articles on mitochondrial potassium channels.
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22
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Yu HG, Sizemore G, Smoot K, Perrotta P. Detecting SARS-CoV-2 Orf3a and E ion channel activity in COVID-19 blood samples. J Clin Transl Sci 2021; 5:e196. [PMID: 34873451 PMCID: PMC8632412 DOI: 10.1017/cts.2021.856] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 09/02/2021] [Accepted: 09/06/2021] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND SARS-CoV-2 has been found in the heart of COVID-19 patients. It is unclear how the virus passes from the upper respiratory tract to the myocardium. We hypothesized that SARS-CoV-2 is present in the blood of COVID-19 infected patients, spreading to other organs such as heart. METHODS We targeted two viroporins, Orf3a and E, in SARS-CoV-2. Orf3a and E form non-voltage-gated ion channels. A combined fluorescence potassium ion assay with three channel modulators (4-aminopyridine, emodin-Orf3a channel blocker, and gliclazide-E channel blocker) was developed to detect SARS-CoV-2 Orf3a/E channel activity. In blood samples, we subtracted the fluorescence signals in the absence and presence of emodin/gliclazide to detect Orf3a and E channel activity. RESULTS In lentivirus-spiked samples, we detected significant channel activity of Orf3a/E based on increase in fluorescence induced by 4-aminopyridine, and this increase in fluorescence was inhibited by emodin and gliclazide. In 18 antigen/PCR-positive samples, our test results found 15 are positive, demonstrating 83.3% concordance. In 24 antigen/PCR-negative samples, our test results found 21 are negative, showing 87.5% concordance. CONCLUSIONS We developed a cell-free test that can detect Orf3a/E channel activity of SARS-CoV-2 in blood samples from COVID-19-infected individuals, confirming a hypothesis that the virus spreads to the heart via blood circulation.
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Affiliation(s)
- Han-Gang Yu
- Department of Physiology and Pharmacology, School of Medicine, West Virginia University, Morgantown, WV, USA
| | | | - Katy Smoot
- Department of Pathology, Anatomy and Laboratory Medicine, School of Medicine, West Virginia University, Morgantown, WV, USA
| | - Peter Perrotta
- Department of Pathology, Anatomy and Laboratory Medicine, School of Medicine, West Virginia University, Morgantown, WV, USA
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23
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Dvorak V, Wiedmer T, Ingles-Prieto A, Altermatt P, Batoulis H, Bärenz F, Bender E, Digles D, Dürrenberger F, Heitman LH, IJzerman AP, Kell DB, Kickinger S, Körzö D, Leippe P, Licher T, Manolova V, Rizzetto R, Sassone F, Scarabottolo L, Schlessinger A, Schneider V, Sijben HJ, Steck AL, Sundström H, Tremolada S, Wilhelm M, Wright Muelas M, Zindel D, Steppan CM, Superti-Furga G. An Overview of Cell-Based Assay Platforms for the Solute Carrier Family of Transporters. Front Pharmacol 2021; 12:722889. [PMID: 34447313 PMCID: PMC8383457 DOI: 10.3389/fphar.2021.722889] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 07/19/2021] [Indexed: 12/12/2022] Open
Abstract
The solute carrier (SLC) superfamily represents the biggest family of transporters with important roles in health and disease. Despite being attractive and druggable targets, the majority of SLCs remains understudied. One major hurdle in research on SLCs is the lack of tools, such as cell-based assays to investigate their biological role and for drug discovery. Another challenge is the disperse and anecdotal information on assay strategies that are suitable for SLCs. This review provides a comprehensive overview of state-of-the-art cellular assay technologies for SLC research and discusses relevant SLC characteristics enabling the choice of an optimal assay technology. The Innovative Medicines Initiative consortium RESOLUTE intends to accelerate research on SLCs by providing the scientific community with high-quality reagents, assay technologies and data sets, and to ultimately unlock SLCs for drug discovery.
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Affiliation(s)
- Vojtech Dvorak
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Tabea Wiedmer
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Alvaro Ingles-Prieto
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | | | - Helena Batoulis
- Drug Discovery Sciences–Lead Discovery, Bayer Pharmaceuticals, Wuppertal, Germany
| | - Felix Bärenz
- Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany
| | - Eckhard Bender
- Drug Discovery Sciences–Lead Discovery, Bayer Pharmaceuticals, Wuppertal, Germany
| | - Daniela Digles
- Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | | | - Laura H. Heitman
- Division of Drug Discovery and Safety, LACDR, Leiden University, Leiden, Netherlands
| | - Adriaan P. IJzerman
- Division of Drug Discovery and Safety, LACDR, Leiden University, Leiden, Netherlands
| | - Douglas B. Kell
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
- Novo Nordisk Foundation Centre for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Stefanie Kickinger
- Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | - Daniel Körzö
- Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | - Philipp Leippe
- Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Thomas Licher
- Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany
| | | | | | | | | | - Avner Schlessinger
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Vanessa Schneider
- Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | - Hubert J. Sijben
- Division of Drug Discovery and Safety, LACDR, Leiden University, Leiden, Netherlands
| | | | | | | | | | - Marina Wright Muelas
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Diana Zindel
- Drug Discovery Sciences–Lead Discovery, Bayer Pharmaceuticals, Wuppertal, Germany
| | - Claire M. Steppan
- Pfizer Worldwide Research, Development and Medical, Groton, MA, United States
| | - Giulio Superti-Furga
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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24
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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.
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25
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Rácz A, Bajusz D, Miranda-Quintana RA, Héberger K. Machine learning models for classification tasks related to drug safety. Mol Divers 2021; 25:1409-1424. [PMID: 34110577 PMCID: PMC8342376 DOI: 10.1007/s11030-021-10239-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/27/2021] [Indexed: 12/23/2022]
Abstract
In this review, we outline the current trends in the field of machine learning-driven classification studies related to ADME (absorption, distribution, metabolism and excretion) and toxicity endpoints from the past six years (2015-2021). The study focuses only on classification models with large datasets (i.e. more than a thousand compounds). A comprehensive literature search and meta-analysis was carried out for nine different targets: hERG-mediated cardiotoxicity, blood-brain barrier penetration, permeability glycoprotein (P-gp) substrate/inhibitor, cytochrome P450 enzyme family, acute oral toxicity, mutagenicity, carcinogenicity, respiratory toxicity and irritation/corrosion. The comparison of the best classification models was targeted to reveal the differences between machine learning algorithms and modeling types, endpoint-specific performances, dataset sizes and the different validation protocols. Based on the evaluation of the data, we can say that tree-based algorithms are (still) dominating the field, with consensus modeling being an increasing trend in drug safety predictions. Although one can already find classification models with great performances to hERG-mediated cardiotoxicity and the isoenzymes of the cytochrome P450 enzyme family, these targets are still central to ADMET-related research efforts.
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Affiliation(s)
- Anita Rácz
- Plasma Chemistry Research Group, Research Centre for Natural Sciences, Magyar tudósok krt. 2, Budapest, 1117, Hungary.
| | - Dávid Bajusz
- Medicinal Chemistry Research Group, Research Centre for Natural Sciences, Magyar tudósok krt. 2, Budapest, 1117, Hungary
| | | | - Károly Héberger
- Plasma Chemistry Research Group, Research Centre for Natural Sciences, Magyar tudósok krt. 2, Budapest, 1117, Hungary.
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26
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Loza-Huerta A, Milo E, Picones A, Hernández-Cruz A, Luis E. Thallium-sensitive fluorescent assay reveals loperamide as a new inhibitor of the potassium channel Kv10.1. Pharmacol Rep 2021; 73:1744-1753. [PMID: 34213738 DOI: 10.1007/s43440-021-00304-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 06/21/2021] [Accepted: 06/23/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND Ion channels have been proposed as therapeutic targets for different types of malignancies. One of the most studied ion channels in cancer is the voltage-gated potassium channel ether-à-go-go 1 or Kv10.1. Various studies have shown that Kv10.1 expression induces the proliferation of several cancer cell lines and in vivo tumor models, while blocking or silencing inhibits proliferation. Kv10.1 is a promising target for drug discovery modulators that could be used in cancer treatment. This work aimed to screen for new Kv10.1 channel modulators using a thallium influx-based assay. METHODS Pharmacological effects of small molecules on Kv10.1 channel activity were studied using a thallium-based fluorescent assay and patch-clamp electrophysiological recordings, both performed in HEK293 stably expressing the human Kv10.1 potassium channel. RESULTS In thallium-sensitive fluorescent assays, we found that the small molecules loperamide and amitriptyline exert a potent inhibition on the activity of the oncogenic potassium channel Kv10.1. These results were confirmed by electrophysiological recordings, which showed that loperamide and amitriptyline decreased the amplitude of Kv10.1 currents in a dose-dependent manner. Both drugs could be promising tools for further studies. CONCLUSIONS Thallium-sensitive fluorescent assay represents a reliable methodological tool for the primary screening of different molecules with potential activity on Kv10.1 channels or other K+ channels.
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Affiliation(s)
- Arlet Loza-Huerta
- Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n, C.U. 04510, Mexico City, Mexico
| | - Edgar Milo
- Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n, C.U. 04510, Mexico City, Mexico
| | - Arturo Picones
- Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n, C.U. 04510, Mexico City, Mexico
| | - Arturo Hernández-Cruz
- Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n, C.U. 04510, Mexico City, Mexico.,Departamento de Neurociencia Cognitiva, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n, C.U. 04510, Mexico City, Mexico
| | - Enoch Luis
- Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n, C.U. 04510, Mexico City, Mexico. .,Cátedras CONACYT - Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n, C.U. 04510, Mexico City, Mexico.
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27
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Mathie A, Veale EL, Golluscio A, Holden RG, Walsh Y. Pharmacological Approaches to Studying Potassium Channels. Handb Exp Pharmacol 2021; 267:83-111. [PMID: 34195873 DOI: 10.1007/164_2021_502] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this review, we consider the pharmacology of potassium channels from the perspective of these channels as therapeutic targets. Firstly, we describe the three main families of potassium channels in humans and disease states where they are implicated. Secondly, we describe the existing therapeutic agents which act on potassium channels and outline why these channels represent an under-exploited therapeutic target with potential for future drug development. Thirdly, we consider the evidence desired in order to embark on a drug discovery programme targeting a particular potassium channel. We have chosen two "case studies": activators of the two-pore domain potassium (K2P) channel TREK-2 (K2P10.1), for the treatment of pain and inhibitors of the voltage-gated potassium channel KV1.3, for use in autoimmune diseases such as multiple sclerosis. We describe the evidence base to suggest why these are viable therapeutic targets. Finally, we detail the main technical approaches available to characterise the pharmacology of potassium channels and identify novel regulatory compounds. We draw particular attention to the Comprehensive in vitro Proarrhythmia Assay initiative (CiPA, https://cipaproject.org ) project for cardiac safety, as an example of what might be both desirable and possible in the future, for ion channel regulator discovery projects.
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Affiliation(s)
- Alistair Mathie
- Medway School of Pharmacy, University of Kent, Kent, UK. .,Medway School of Pharmacy, University of Greenwich, London, UK. .,School of Engineering, Arts, Science and Technology, University of Suffolk, Ipswich, UK.
| | - Emma L Veale
- Medway School of Pharmacy, University of Kent, Kent, UK.,Medway School of Pharmacy, University of Greenwich, London, UK
| | - Alessia Golluscio
- Medway School of Pharmacy, University of Kent, Kent, UK.,Medway School of Pharmacy, University of Greenwich, London, UK
| | - Robyn G Holden
- Medway School of Pharmacy, University of Kent, Kent, UK.,Medway School of Pharmacy, University of Greenwich, London, UK
| | - Yvonne Walsh
- Medway School of Pharmacy, University of Kent, Kent, UK.,Medway School of Pharmacy, University of Greenwich, London, UK
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28
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Kim K, Christov PP, Romaine I, Tian J, Jana S, Lamers AP, Dutter BF, Scaggs T, Jeon K, Guttentag B, Weaver CD, Lindsley CW, Waterson AG, Sulikowski GA. Ten-Year Retrospective of the Vanderbilt Institute of Chemical Biology Chemical Synthesis Core. ACS Chem Biol 2021; 16:787-793. [PMID: 33877812 DOI: 10.1021/acschembio.0c00818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Chemical synthesis has been described as a central science. Its practice provides access to the chemical structures of known and/or designed function. In particular, human health is greatly impacted by synthesis that enables advancements in both basic science discoveries in chemical biology as well as translational research that can lead to new therapeutics. To support the chemical synthesis needs of investigators across campus, the Vanderbilt Institute of Chemical Biology established a chemical synthesis core as part of its foundation in 2008. Provided in this Review are examples of synthetic products, known and designed, produced in the core over the past 10 years.
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Affiliation(s)
- Kwangho Kim
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Plamen P. Christov
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Ian Romaine
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Jianhua Tian
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Somnath Jana
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Alexander P. Lamers
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Brendan F. Dutter
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Toya Scaggs
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Kyouk Jeon
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Benjamin Guttentag
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - C. David Weaver
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Craig W. Lindsley
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee 37232, United States
- Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Alex G. Waterson
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Gary A. Sulikowski
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
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29
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Therapeutic Antibodies Targeting Potassium Ion Channels. Handb Exp Pharmacol 2021; 267:507-545. [PMID: 33963460 DOI: 10.1007/164_2021_464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Monoclonal antibodies combine specificity and high affinity binding with excellent pharmacokinetic properties and are rapidly being developed for a wide range of drug targets including clinically important potassium ion channels. Nonetheless, while therapeutic antibodies come with great promise, K+ channels represent particularly difficult targets for biologics development for a variety of reasons that include their dynamic structures and relatively small extracellular loops, their high degree of sequence conservation (leading to immune tolerance), and their generally low-level expression in vivo. The process is made all the more difficult when large numbers of antibody candidates must be screened for a given target, or when lead candidates fail to cross-react with orthologous channels in animal disease models due to their highly selective binding properties. While the number of antibodies targeting potassium channels in preclinical or clinical development is still modest, significant advances in the areas of protein expression and antibody screening are converging to open the field to an avalanche of new drugs. Here, the opportunities and constraints associated with the discovery of antibodies against K+ channels are discussed, with an emphasis on novel technologies that are opening the field to exciting new possibilities for biologics development.
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30
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Su S, Sun J, Wang Y, Xu Y. Cardiac hERG K + Channel as Safety and Pharmacological Target. Handb Exp Pharmacol 2021; 267:139-166. [PMID: 33829343 DOI: 10.1007/164_2021_455] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The human ether-á-go-go related gene (hERG, KCNH2) encodes the pore-forming subunit of the potassium channel responsible for a fast component of the cardiac delayed rectifier potassium current (IKr). Outward IKr is an important determinant of cardiac action potential (AP) repolarization and effectively controls the duration of the QT interval in humans. Dysfunction of hERG channel can cause severe ventricular arrhythmias and thus modulators of the channel, including hERG inhibitors and activators, continue to attract intense pharmacological interest. Certain inhibitors of hERG channel prolong the action potential duration (APD) and effective refractory period (ERP) to suppress premature ventricular contraction and are used as class III antiarrhythmic agents. However, a reduction of the hERG/IKr current has been recognized as a predominant mechanism responsible for the drug-induced delayed repolarization known as acquired long QT syndromes (LQTS), which is linked to an increased risk for "torsades de pointes" (TdP) ventricular arrhythmias and sudden cardiac death. Many drugs of different classes and structures have been identified to carry TdP risk. Hence, assessing hERG/IKr blockade of new drug candidates is mandatory in the drug development process according to the regulatory agencies. In contrast, several hERG channel activators have been shown to enhance IKr and shorten the APD and thus might have potential antiarrhythmic effects against pathological LQTS. However, these activators may also be proarrhythmic due to excessive shortening of APD and the ERP.
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Affiliation(s)
- Shi Su
- Department of Pharmacology, Hebei Medical University, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei, China
| | - Jinglei Sun
- Department of Pharmacology, Hebei Medical University, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei, China
| | - Yi Wang
- Department of Pharmacology, Hebei Medical University, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei, China
| | - Yanfang Xu
- Department of Pharmacology, Hebei Medical University, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei, China.
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31
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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.
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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
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32
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Delpire E. Advances in the development of novel compounds targeting cation-chloride cotransporter physiology. Am J Physiol Cell Physiol 2021; 320:C324-C340. [PMID: 33356948 PMCID: PMC8294628 DOI: 10.1152/ajpcell.00566.2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 12/16/2020] [Accepted: 12/17/2020] [Indexed: 01/05/2023]
Abstract
For about half a century, the pharmacology of electroneutral cation-chloride cotransporters has been dominated by a few drugs that are widely used in clinical medicine. Because these diuretic drugs are so good at what they do, there has been little incentive in expanding their pharmacology. The increasing realization that cation-chloride cotransporters are involved in many other key physiological processes and the knowledge that different tissues express homologous proteins with matching transport functions have rekindled interest in drug discovery. This review summarizes the methods available to assess the function of these transporters and describe the multiple efforts that have made to identify new compounds. We describe multiple screens targeting KCC2 function and one screen designed to find compounds that discriminate between NKCC1 and NKCC2. Two of the KCC2 screens identified new inhibitors that are 3-4 orders of magnitude more potent than furosemide. Additional screens identified compounds that purportedly increase cell surface expression of the cotransporter, as well as several FDA-approved drugs that increase KCC2 transcription and expression. The technical details of each screen biased them toward specific processes in the life cycle of the transporter, making these efforts independent and complementary. In addition, each drug discovery effort contributes to our understanding of the biology of the cotransporters.
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Affiliation(s)
- Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee
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33
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Song L, Barrett DG, Cox KL, Efanov AM, Syed SK, Tomandl D, Willard FS. A High-Throughput Assay for the Pancreatic Islet Beta-Cell Potassium Channel: Use in the Pharmacological Characterization of Insulin Secretagogues Identified from Phenotypic Screening. Assay Drug Dev Technol 2020; 19:27-37. [PMID: 33164547 DOI: 10.1089/adt.2020.1011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Phenotypic screening is a neoclassical approach for drug discovery. We conducted phenotypic screening for insulin secretion enhancing agents using INS-1E insulinoma cells as a model system for pancreatic beta-cells. A principal regulator of insulin secretion in beta-cells is the metabolically regulated potassium channel Kir6.2/SUR1 complex. To characterize hit compounds, we developed an assay to quantify endogenous potassium channel activity in INS-1E cells. We quantified ligand-regulated potassium channel activity in INS-1E cells using fluorescence imaging and thallium flux. Potassium channel activity was metabolically regulated and coupled to insulin secretion. The pharmacology of channel opening agents (diazoxide) and closing agents (sulfonylureas) was used to validate the applicability of the assay. A precise high-throughput assay was enabled, and phenotypic screening hits were triaged to enable a higher likelihood of discovering chemical matter with novel and useful mechanisms of action.
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Affiliation(s)
- Luyan Song
- Quantitative Biology, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - David G Barrett
- Discovery Chemistry, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - Karen L Cox
- Quantitative Biology, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - Alexander M Efanov
- Diabetes and Complications Therapeutic Area, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - Samreen K Syed
- Diabetes and Complications Therapeutic Area, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - Dirk Tomandl
- Discovery Informatics, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - Francis S Willard
- Quantitative Biology, Lilly Research Laboratories, Indianapolis, Indiana, USA
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34
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Stoveken HM, Zucca S, Masuho I, Grill B, Martemyanov KA. The orphan receptor GPR139 signals via G q/11 to oppose opioid effects. J Biol Chem 2020; 295:10822-10830. [PMID: 32576659 DOI: 10.1074/jbc.ac120.014770] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 06/22/2020] [Indexed: 12/13/2022] Open
Abstract
The interplay between G protein-coupled receptors (GPCRs) is critical for controlling neuronal activity that shapes neuromodulatory outcomes. Recent evidence indicates that the orphan receptor GPR139 influences opioid modulation of key brain circuits by opposing the actions of the µ-opioid receptor (MOR). However, the function of GPR139 and its signaling mechanisms are poorly understood. In this study, we report that GPR139 activates multiple heterotrimeric G proteins, including members of the Gq/11 and Gi/o families. Using a panel of reporter assays in reconstituted HEK293T/17 cells, we found that GPR139 functions via the Gq/11 pathway and thereby distinctly regulates cellular effector systems, including stimulation of cAMP production and inhibition of G protein inward rectifying potassium (GIRK) channels. Electrophysiological recordings from medial habenular neurons revealed that GPR139 signaling via Gq/11 is necessary and sufficient for counteracting MOR-mediated inhibition of neuronal firing. These results uncover a mechanistic interplay between GPCRs involved in controlling opioidergic neuromodulation in the brain.
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Affiliation(s)
- Hannah M Stoveken
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, USA
| | - Stefano Zucca
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, USA
| | - Ikuo Masuho
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, USA
| | - Brock Grill
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, USA
| | - Kirill A Martemyanov
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, USA
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35
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Walsh KB. Screening Technologies for Inward Rectifier Potassium Channels: Discovery of New Blockers and Activators. SLAS DISCOVERY 2020; 25:420-433. [PMID: 32292089 DOI: 10.1177/2472555220905558] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
K+ channels play a critical role in maintaining the normal electrical activity of excitable cells by setting the cell resting membrane potential and by determining the shape and duration of the action potential. In nonexcitable cells, K+ channels establish electrochemical gradients necessary for maintaining salt and volume homeostasis of body fluids. Inward rectifier K+ (Kir) channels typically conduct larger inward currents than outward currents, resulting in an inwardly rectifying current versus voltage relationship. This property of inward rectification results from the voltage-dependent block of the channels by intracellular polyvalent cations and makes these channels uniquely designed for maintaining the resting potential near the K+ equilibrium potential (EK). The Kir family of channels consist of seven subfamilies of channels (Kir1.x through Kir7.x) that include the classic inward rectifier (Kir2.x) channel, the G-protein-gated inward rectifier K+ (GIRK) (Kir3.x), and the adenosine triphosphate (ATP)-sensitive (KATP) (Kir 6.x) channels as well as the renal Kir1.1 (ROMK), Kir4.1, and Kir7.1 channels. These channels not only function to regulate electrical/electrolyte transport activity, but also serve as effector molecules for G-protein-coupled receptors (GPCRs) and as molecular sensors for cell metabolism. Of significance, Kir channels represent promising pharmacological targets for treating a number of clinical conditions, including cardiac arrhythmias, anxiety, chronic pain, and hypertension. This review provides a brief background on the structure, function, and pharmacology of Kir channels and then focuses on describing and evaluating current high-throughput screening (HTS) technologies, such as membrane potential-sensitive fluorescent dye assays, ion flux measurements, and automated patch clamp systems used for Kir channel drug discovery.
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Affiliation(s)
- Kenneth B Walsh
- Department of Pharmacology, Physiology & Neuroscience, School of Medicine, University of South Carolina, Columbia, SC, USA
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36
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Korotkov SM, Nesterov VP, Belostotskaya GB, Brailovskaya IV, Novozhilov AV, Sobol CV. Influence of Tl(+) on the Ca(2+) and Na(+) movement across rat neonatal cardiomyocytes and rat heart mitochondria membranes. UKRAINIAN BIOCHEMICAL JOURNAL 2020. [DOI: 10.15407/ubj92.01.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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37
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High-Throughput Fluorescence Assays for Ion Channels and GPCRs. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:27-72. [DOI: 10.1007/978-3-030-12457-1_3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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38
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Fischer RA, Risner ML, Roux AL, Wareham LK, Sappington RM. Impairment of Membrane Repolarization Accompanies Axon Transport Deficits in Glaucoma. Front Neurosci 2019; 13:1139. [PMID: 31736686 PMCID: PMC6838637 DOI: 10.3389/fnins.2019.01139] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 10/09/2019] [Indexed: 12/12/2022] Open
Abstract
Glaucoma is a leading cause of blindness worldwide, resulting from degeneration of retinal ganglion cells (RGCs), which form the optic nerve. In glaucoma, axon transport deficits appear to precede structural degeneration of RGC axons. The period of time between the onset of axon transport deficits and the structural degeneration of RGC axons may represent a therapeutic window for the prevention of irreversible vision loss. However, it is unclear how deficits in axon transport relate to the electrophysiological capacity of RGCs to produce and maintain firing frequencies that encode visual stimuli. Here, we examined the electrophysiological signature of individual RGCs in glaucomatous retina with respect to axon transport facility. Utilizing the Microbead Occlusion Model of murine ocular hypertension, we performed electrophysiological recordings of RGCs with and without deficits in anterograde axon transport. We found that RGCs with deficits in axon transport have a reduced ability to maintain spiking frequency that arises from elongation of the repolarization phase of the action potential. This repolarization phenotype arises from reduced cation flux and K+ dyshomeostasis that accompanies pressure-induced decreases in Na/K-ATPase expression and activity. In vitro studies with purified RGCs indicate that elevated pressure induces early internalization of Na/K-ATPase that, when reversed, stabilizes cation flux and prevents K+ dyshomeostasis. Furthermore, pharmacological inhibition of the Na/K-ATPase is sufficient to replicate pressure-induced cation influx and repolarization phase phenotypes in healthy RGCs. These studies suggest that deficits in axon transport also likely reflect impaired electrophysiological function of RGCs. Our findings further identify a failure to maintain electrochemical gradients and cation dyshomeostasis as an early phenotype of glaucomatous pathology in RGCs that may have significant bearing on efforts to restore RGC health in diseased retina.
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Affiliation(s)
- Rachel A Fischer
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States
| | - Michael L Risner
- Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, United States.,Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Abigail L Roux
- Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Lauren K Wareham
- Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Rebecca M Sappington
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States.,Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, United States.,Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN, United States
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39
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Porter JD, Vivas O, Weaver CD, Alsafran A, DiMilo E, Arnold LA, Dickson EJ, Dockendorff C. An anthrone-based Kv7.2/7.3 channel blocker with improved properties for the investigation of psychiatric and neurodegenerative disorders. Bioorg Med Chem Lett 2019; 29:126681. [PMID: 31668424 DOI: 10.1016/j.bmcl.2019.126681] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 09/09/2019] [Indexed: 12/22/2022]
Abstract
A set of novel Kv7.2/7.3 (KCNQ2/3) channel blockers was synthesized to address several liabilities of the known compounds XE991 (metabolic instability and CYP inhibition) and the clinical compound DMP 543 (acid instability, insolubility, and lipophilicity). Using the anthrone scaffold of the prior channel blockers, alternative heteroarylmethyl substituents were installed via enolate alkylation reactions. Incorporation of a pyridazine and a fluorinated pyridine gave an analog (compound 18, JDP-107) with a promising combination of potency (IC50 = 0.16 μM in a Kv7.2 thallium flux assay), efficacy in a Kv7.2/7.3 patch clamp assay, and drug-like properties.
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Affiliation(s)
- Jacob D Porter
- Department of Chemistry, Marquette University, P.O. Box 1881, Milwaukee, WI 53201-1881, USA
| | - Oscar Vivas
- Department of Physiology & Membrane Biology, University of California, 1 Shields Avenue, Davis, CA 95616, USA
| | - C David Weaver
- Departments of Pharmacology and Chemistry, Vanderbilt University, Vanderbilt Institute of Chemical Biology, Nashville, TN 37232, USA
| | - Abdulmohsen Alsafran
- Department of Chemistry, Marquette University, P.O. Box 1881, Milwaukee, WI 53201-1881, USA
| | - Elliot DiMilo
- Department of Chemistry and Biochemistry, Milwaukee Institute for Drug Discovery, University of Wisconsin, Milwaukee, WI 53211, USA
| | - Leggy A Arnold
- Department of Chemistry and Biochemistry, Milwaukee Institute for Drug Discovery, University of Wisconsin, Milwaukee, WI 53211, USA
| | - Eamonn J Dickson
- Department of Physiology & Membrane Biology, University of California, 1 Shields Avenue, Davis, CA 95616, USA
| | - Chris Dockendorff
- Department of Chemistry, Marquette University, P.O. Box 1881, Milwaukee, WI 53201-1881, USA.
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40
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Korotkov SM, Nesterov VP, Sobol KV. The Effects of Thallium on the Spontaneous Contraction of the Heart Muscle and the Energetic Processes in Cardiomyocyte Mitochondria. Biophysics (Nagoya-shi) 2019. [DOI: 10.1134/s0006350919050117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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41
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Fischer RA, Roux AL, Wareham LK, Sappington RM. Pressure-dependent modulation of inward-rectifying K + channels: implications for cation homeostasis and K + dynamics in glaucoma. Am J Physiol Cell Physiol 2019; 317:C375-C389. [PMID: 31166711 DOI: 10.1152/ajpcell.00444.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Glaucoma is the leading cause of blindness worldwide, resulting from degeneration of retinal ganglion cells (RGCs), which form the optic nerve. Prior to structural degeneration, RGCs exhibit physiological deficits. Müller glia provide homeostatic regulation of ions that supports RGC physiology through a process called K+ siphoning. Recent studies suggest that several retinal conditions, including glaucoma, involve changes in the expression of K+ channels in Müller glia. To clarify whether glaucoma-related stressors directly alter expression and function of K+ channels in Müller glia, we examined changes in the expression of inwardly rectifying K+ (Kir) channels and two-pore domain (K2P) channels in response to elevated intraocular pressure (IOP) in vivo and in vitro in primary cultures of Müller glia exposed to elevated hydrostatic pressure. We then measured outcomes of cell health, cation homeostasis, and cation flux in Müller glia cultures. Transcriptome analysis in a murine model of microbead-induced glaucoma revealed pressure-dependent downregulation of Kir and K2P channels in vivo. Changes in the expression and localization of Kir and K2P channels in response to elevated pressure were also found in Müller glia in vitro. Finally, we found that elevated pressure compromises the plasma membrane of Müller glia and induces cation dyshomeostasis that involves changes in ion flux through cation channels. Pressure-induced changes in cation flux precede both cation dyshomeostasis and membrane compromise. Our findings have implications for Müller glia responses to pressure-related conditions, i.e., glaucoma, and identify cation dyshomeostasis as a potential contributor to electrophysiological impairment observed in RGCs of glaucomatous retina.
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Affiliation(s)
- Rachel A Fischer
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Abigail L Roux
- Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Lauren K Wareham
- Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Rebecca M Sappington
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee.,Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee.,Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee
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42
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Bock C, Surur AS, Beirow K, Kindermann MK, Schulig L, Bodtke A, Bednarski PJ, Link A. Sulfide Analogues of Flupirtine and Retigabine with Nanomolar K V 7.2/K V 7.3 Channel Opening Activity. ChemMedChem 2019; 14:952-964. [PMID: 30861620 DOI: 10.1002/cmdc.201900112] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Indexed: 12/18/2022]
Abstract
The potassium channel openers flupirtine and retigabine have proven to be valuable analgesics or antiepileptics. Their recent withdrawal due to occasional hepatotoxicity and tissue discoloration, respectively, leaves a therapeutic niche unfilled. Metabolic oxidation of both drugs gives rise to the formation of electrophilic quinones. These elusive, highly reactive metabolites may induce liver injury in the case of flupirtine and blue tissue discoloration after prolonged intake of retigabine. We examined which structural features can be altered to avoid the detrimental oxidation of the aromatic ring and shift oxidation toward the formation of more benign metabolites. Structure-activity relationship studies were performed to evaluate the KV 7.2/3 channel opening activity of 45 derivatives. Sulfide analogues were identified that are devoid of the risk of quinone formation, but possess potent KV 7.2/3 opening activity. For example, flupirtine analogue 3-(3,5-difluorophenyl)-N-(6-(isobutylthio)-2-(pyrrolidin-1-yl)pyridin-3-yl)propanamide (48) has 100-fold enhanced activity (EC50 =1.4 nm), a vastly improved toxicity/activity ratio, and the same efficacy as retigabine in vitro.
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Affiliation(s)
- Christian Bock
- Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 17, 17489, Greifswald, Germany
| | - Abdrrahman S Surur
- Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 17, 17489, Greifswald, Germany
| | - Kristin Beirow
- Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 17, 17489, Greifswald, Germany
| | - Markus K Kindermann
- Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 17, 17489, Greifswald, Germany
| | - Lukas Schulig
- Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 17, 17489, Greifswald, Germany
| | - Anja Bodtke
- Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 17, 17489, Greifswald, Germany
| | - Patrick J Bednarski
- Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 17, 17489, Greifswald, Germany
| | - Andreas Link
- Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 17, 17489, Greifswald, Germany
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43
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Dutter BF, Ender A, Sulikowski GA, Weaver CD. Rhodol-based thallium sensors for cellular imaging of potassium channel activity. Org Biomol Chem 2019; 16:5575-5579. [PMID: 30051127 DOI: 10.1039/c8ob01098f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Thallium (Tl+) flux assays enable imaging of potassium (K+) channel activity in cells and tissues by exploiting the permeability of K+ channels to Tl+ coupled with a fluorescent Tl+ sensitive dye. Common Tl+ sensing dyes utilize fluorescein as the fluorophore though fluorescein exhibits certain undesirable properties in these assays including short excitation wavelengths and pH sensitivity. To overcome these drawbacks, the replacement of fluorescein with rhodols was investigated. A library of 13 rhodol-based Tl+ sensors was synthesized and their properties and performance in Tl+ flux assays evaluated. The dimethyl rhodol Tl+ sensor emerged as the best of the series and performed comparably to fluorescein-based sensors while demonstrating greater pH tolerance in the physiological range and excitation and emission spectra 30 nm red-shifted from fluorescein.
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Affiliation(s)
- Brendan F Dutter
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA.
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44
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Bock C, Beirow K, Surur AS, Schulig L, Bodtke A, Bednarski PJ, Link A. Synthesis and potassium K V7 channel opening activity of thioether analogues of the analgesic flupirtine. Org Biomol Chem 2019; 16:8695-8699. [PMID: 30403254 DOI: 10.1039/c8ob02530d] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Flupirtine, an opener of neuronal voltage gated potassium channels (KV7.2/3), has been used as a therapeutic alternative for pain treatment in patients refractory to NSAIDs and opioids. Because flupirtine is associated with rare but fatal drug-induced liver injury that may result from the formation of toxic metabolites upon metabolic oxidation, we synthesized novel derivatives with the goal of identifying equally active and ultimately safer KV7.2/3 channel openers. Four thioether analogues were designed to lack a nitrogen atom that would be a prerequisite for the formation of toxic para-quinone diimines, and form sulfoxide and sulfone metabolites instead. KV7.2/3 channel opening activity and hepatotoxicity data of twelve novel flupirtine analogues, four thioethers and their respective sulfoxide and sulfone metabolites are reported.
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Affiliation(s)
- Christian Bock
- Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 17, 17487 Greifswald, Germany.
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45
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Kozek KA, Du Y, Sharma S, Prael FJ, Spitznagel BD, Kharade SV, Denton JS, Hopkins CR, Weaver CD. Discovery and Characterization of VU0529331, a Synthetic Small-Molecule Activator of Homomeric G Protein-Gated, Inwardly Rectifying, Potassium (GIRK) Channels. ACS Chem Neurosci 2019; 10:358-370. [PMID: 30136838 PMCID: PMC6528656 DOI: 10.1021/acschemneuro.8b00287] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
G protein-gated, inwardly rectifying, potassium (GIRK) channels are important regulators of cellular excitability throughout the body. GIRK channels are heterotetrameric and homotetrameric combinations of the Kir3.1-4 (GIRK1-4) subunits. Different subunit combinations are expressed throughout the central nervous system (CNS) and the periphery, and most of these combinations contain a GIRK1 subunit. For example, the predominance of GIRK channels in the CNS are composed of GIRK1 and GIRK2 subunits, while the GIRK channels in cardiac atrial myocytes are made up mostly of GIRK1 and GIRK4 subunits. Although the vast majority of GIRK channels contain a GIRK1 subunit, discrete populations of cells that express non-GIRK1-containing GIRK (non-GIRK1/X) channels do exist. For instance, dopaminergic neurons in the ventral tegmental area of the brain, associated with addiction and reward, do not express the GIRK1 subunit. Targeting these non-GIRK1/X channels with subunit-selective pharmacological probes could lead to important insights into how GIRK channels are involved in reward and addiction. Such insights may, in turn, reveal therapeutic opportunities for the treatment or prevention of addiction. Previously, our laboratory discovered small molecules that can specifically modulate the activity of GIRK1-containing GIRK channels. However, efforts to generate compounds active on non-GIRK1/X channels from these scaffolds have been unsuccessful. Recently, ivermectin was shown to modulate non-GIRK1/X channels, and historically, ivermectin is known to modulate a wide variety of neuronal channels and receptors. Further, ivermectin is a complex natural product, which makes it a challenging starting point for development of more selective, effective, and potent compounds. Thus, while ivermectin provides proof-of-concept as a non-GIRK1/X channel activator, it is of limited utility. Therefore, we sought to discover a synthetic small molecule that would serve as a starting point for the development of non-GIRK1/X channel modulators. To accomplish this, we used a high-throughput thallium flux assay to screen a 100 000-compound library in search of activators of homomeric GIRK2 channels. Using this approach, we discovered VU0529331, the first synthetic small molecule reported to activate non-GIRK1/X channels, to our knowledge. This discovery represents the first step toward developing potent and selective non-GIRK1/X channel probes. Such molecules will help elucidate the role of GIRK channels in addiction, potentially establishing a foundation for future development of therapies utilizing targeted GIRK channel modulation.
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Affiliation(s)
- Krystian A. Kozek
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
- vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, USA
- vanderbilt Medical Scientist Training Program, Vanderbilt University, Nashville, Tennessee, USA
| | - Yu Du
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
- vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Swagat Sharma
- Department of Pharmaceutical Sciences, Center for Drug Discovery, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Francis J. Prael
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
- vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Brittany D. Spitznagel
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
- vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Sujay V. Kharade
- Department of Anesthesiology, Vanderbilt University, Nashville, Tennessee, USA
| | - Jerod S. Denton
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
- Department of Anesthesiology, Vanderbilt University, Nashville, Tennessee, USA
| | - Corey R. Hopkins
- Department of Pharmaceutical Sciences, Center for Drug Discovery, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - C. David Weaver
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
- vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, USA
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46
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Colley CS, England E, Linley JE, Wilkinson TCI. Screening Strategies for the Discovery of Ion Channel Monoclonal Antibodies. ACTA ACUST UNITED AC 2018; 82:e44. [DOI: 10.1002/cpph.44] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Caroline S. Colley
- Antibody Discovery and Protein Engineering, MedImmune; Cambridge United Kingdom
| | - Elizabeth England
- Antibody Discovery and Protein Engineering, MedImmune; Cambridge United Kingdom
| | - John E. Linley
- Neuroscience, IMED Biotech Unit, AstraZeneca; Cambridge United Kingdom
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47
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Fischer RA, Zhang Y, Risner ML, Li D, Xu Y, Sappington RM. Impact of Graphene on the Efficacy of Neuron Culture Substrates. Adv Healthc Mater 2018; 7:e1701290. [PMID: 29943431 PMCID: PMC6105445 DOI: 10.1002/adhm.201701290] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 04/11/2018] [Indexed: 01/09/2023]
Abstract
How graphene influences the behavior of living cells or tissues remains a critical issue for its application in biomedical studies, despite the general acceptance that graphene is biocompatible. While direct contact between cells and graphene is not a requirement for all biomedical applications, it is often mandatory for biosensing. Therefore, it is important to clarify whether graphene impedes the ability of cells to interact with biological elements in their environment. Here, a systematic study is reported to determine whether applying graphene on top of matrix substrates masks interactions between these substrates and retinal ganglion cells (RGCs). Six different platforms are tested for primary RGC cultures with three platforms comprised of matrix substrates compatible with these neurons, and another three having a layer of graphene placed on top of the matrix substrates. The results demonstrate that graphene does not impede interactions between RGCs and underlying substrate matrix, such that their positive or negative effects on neuron viability and vitality are retained. However, direct contact between RGCs and graphene reduces the number, but increases basal activity, of functional cation channels. The data indicate that, when proper baselines are established, graphene is a promising biosensing material for in vitro applications in neuroscience.
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Affiliation(s)
- Rachel A. Fischer
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Department of Pharmacology, Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN 37235, USA
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN 37235, USA
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235, USA
- Department of Physics and Astronomy and Department of Electrical, Engineering and Computer Science, Vanderbilt University, Nashville, TN 37235, USA
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Department of Pharmacology, Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN 37235, USA
| | - Yuchen Zhang
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Department of Pharmacology, Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN 37235, USA
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN 37235, USA
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235, USA
- Department of Physics and Astronomy and Department of Electrical, Engineering and Computer Science, Vanderbilt University, Nashville, TN 37235, USA
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Department of Pharmacology, Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN 37235, USA
| | - Michael L. Risner
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Department of Pharmacology, Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN 37235, USA
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN 37235, USA
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235, USA
- Department of Physics and Astronomy and Department of Electrical, Engineering and Computer Science, Vanderbilt University, Nashville, TN 37235, USA
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Department of Pharmacology, Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN 37235, USA
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48
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Discovery of Beclabuvir: A Potent Allosteric Inhibitor of the Hepatitis C Virus Polymerase. HCV: THE JOURNEY FROM DISCOVERY TO A CURE 2018; 31. [PMCID: PMC7123187 DOI: 10.1007/7355_2018_38] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The discovery of beclabuvir occurred through an iterative series of structure-activity relationship studies directed at the optimization of a novel class of indolobenzazepines. Within this research, a strategic decision to abandon a highly potent but physiochemically problematic series in favor of one of lower molecular weight and potency was key in the realization of the program’s objectives. Subsequent cycles of analog design incorporating progressive conformational constraints successfully addressed off-target liabilities and identified compounds with improved physiochemical profiles. Ultimately, a class of alkyl-bridged piperazine carboxamides was found to be of particular interest, and from this series, beclabuvir was identified as having superior antiviral, safety, and pharmacokinetic properties. The clinical evaluation of beclabuvir in combination with both the NS5A replication complex inhibitor daclatasvir and the NS3 protease inhibitor asunaprevir in a single, fixed-dose formulation (Ximency) resulted in the approval by the Japanese Pharmaceutical and Food Safety Bureau for its use in the treatment of patients infected with genotype 1 HCV.
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Gill S, Gill R, Wen Y, Enderle T, Roth D, Liang D. A High-Throughput Screening Assay for NKCC1 Cotransporter Using Nonradioactive Rubidium Flux Technology. Assay Drug Dev Technol 2018. [PMID: 28631939 DOI: 10.1089/adt.2017.787] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A high-throughput screening (HTS) assay was developed for cotransporter, NKCC1, which is a potential target for the treatment of diverse disorders. This nonradioactive rubidium flux assay coupled with ion channel reader series provides a working screen for this target expressed in human embryonic kidney (HEK) cell line. An eightfold window of detection was achieved with the optimized assay. This new functional assay offered a robust working model for NKCC1 in determining reliable and concordant rank orders of the test compounds supporting its sensitivity and specificity. The robustness of manual assay indicated by Z' of 0.9 qualified its amenability to automation. The Z' of 0.7 was displayed by automated assay employed in high-throughput screening of compound libraries against this target. Being electrically neutral, the NKCC1 screening is difficult to achieve by both manual and automated electrophysiological techniques. These techniques, although considered gold standard, suffer from their inherent problems of being too slow to be in high-throughput format and with high running costs. In addition to being a functional assay for NKCC1, it is nontoxic as compared with thallium flux assay, which is prone to generate high number of false-positive/false-negative rates because of its innate fluorescence issues.
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Affiliation(s)
| | | | - Yang Wen
- 2 Roche Innovation Center Basel , Hoffmann-La Roche, Basel, Switzerland
| | - Thilo Enderle
- 2 Roche Innovation Center Basel , Hoffmann-La Roche, Basel, Switzerland
| | - Doris Roth
- 2 Roche Innovation Center Basel , Hoffmann-La Roche, Basel, Switzerland
| | - Dong Liang
- 1 Aurora Biomed Inc. , Vancouver, Canada
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Philippaert K, Kerselaers S, Voets T, Vennekens R. A Thallium-Based Screening Procedure to Identify Molecules That Modulate the Activity of Ca2+-Activated Monovalent Cation-Selective Channels. SLAS DISCOVERY 2018; 23:341-352. [DOI: 10.1177/2472555217748932] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
TRPM5 functions as a calcium-activated monovalent cation-selective ion channel and is expressed in a variety of cell types. Dysfunction of this type of channel has been recently implied in cardiac arrhythmias, diabetes, and other pathologies. Therefore, a growing interest has emerged to develop the pharmacology of these ion channels. We optimized a screening assay based on the thallium flux through the TRPM5 channel and a fluorescent thallium dye as a probe for channel activity. We show that this assay is capable of identifying molecules that inhibit or potentiate calcium-activated monovalent cation-selective ion channels.
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Affiliation(s)
- Koenraad Philippaert
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KULeuven, Leuven, Vlaams Brabant, Belgium
- TRP Research Platform Leuven (TRPLe), KULeuven, Leuven, Belgium
- VIB Center for Brain & Disease Research, Leuven, Belgium
| | - Sara Kerselaers
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KULeuven, Leuven, Vlaams Brabant, Belgium
- TRP Research Platform Leuven (TRPLe), KULeuven, Leuven, Belgium
- VIB Center for Brain & Disease Research, Leuven, Belgium
| | - Thomas Voets
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KULeuven, Leuven, Vlaams Brabant, Belgium
- TRP Research Platform Leuven (TRPLe), KULeuven, Leuven, Belgium
- VIB Center for Brain & Disease Research, Leuven, Belgium
| | - Rudi Vennekens
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KULeuven, Leuven, Vlaams Brabant, Belgium
- TRP Research Platform Leuven (TRPLe), KULeuven, Leuven, Belgium
- VIB Center for Brain & Disease Research, Leuven, Belgium
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