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Yi M, Wei T, Wang Y, Lu Q, Chen G, Gao X, Geller HM, Chen H, Yu Z. The potassium channel KCa3.1 constitutes a pharmacological target for astrogliosis associated with ischemia stroke. J Neuroinflammation 2017; 14:203. [PMID: 29037241 PMCID: PMC5644250 DOI: 10.1186/s12974-017-0973-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 09/27/2017] [Indexed: 12/11/2022] Open
Abstract
Background Reactive astrogliosis is one of the significantly pathological features in ischemic stroke accompanied with changes in gene expression, morphology, and proliferation. KCa3.1 was involved in TGF-β-induced astrogliosis in vitro and also contributed to astrogliosis-mediated neuroinflammation in neurodegeneration disease. Methods Wild type mice and KCa3.1−/− mice were subjected to permanent middle cerebral artery occlusion (pMCAO) to evaluate the infarct areas by 2,3,5-triphenyltetrazolium hydrochloride staining and neurological deficit. KCa3.1 channels expression and cell localization in the brain of pMCAO mice model were measured by immunoblotting and immunostaining. Glia activation and neuron loss was measured by immunostaining. DiBAC4 (3) and Fluo-4AM were used to measure membrane potential and cytosolic Ca2+ level in oxygen-glucose deprivation induced reactive astrocytes in vitro. Results Immunohistochemistry on pMCAO mice infarcts showed strong upregulation of KCa3.1 immunoreactivity in reactive astrogliosis. KCa3.1−/− mice exhibited significantly smaller infarct areas on pMCAO and improved neurological deficit. Both activated gliosis and neuronal loss were attenuated in KCa3.1−/− pMCAO mice. In the primary cultured astrocytes, the expressions of KCa3.1 and TRPV4 were increased associated with upregulation of astrogliosis marker GFAP induced by oxygen-glucose deprivation. The activation of KCa3.1 hyperpolarized membrane potential and, by promoting the driving force for calcium, induced calcium entry through TRPV4, a cation channel of the transient receptor potential family. Double-labeled staining showed that KCa3.1 and TRPV4 channels co-localized in astrocytes. Blockade of KCa3.1 or TRPV4 inhibited the phenotype switch of reactive astrogliosis. Conclusions Our data suggested that KCa3.1 inhibition might represent a promising therapeutic strategy for ischemia stroke. Electronic supplementary material The online version of this article (10.1186/s12974-017-0973-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mengni Yi
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Tianjiao Wei
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Yanxia Wang
- Experimental Teaching Center of Basic Medicine, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200025, China
| | - Qin Lu
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Gaoxian Chen
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Xiaoling Gao
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Herbert M Geller
- Developmental Neurobiology Section, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Hongzhuan Chen
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
| | - Zhihua Yu
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
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Wegener J. Cell-Based Microarrays for In Vitro Toxicology. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2015; 8:335-358. [PMID: 26077916 DOI: 10.1146/annurev-anchem-071213-020051] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
DNA/RNA and protein microarrays have proven their outstanding bioanalytical performance throughout the past decades, given the unprecedented level of parallelization by which molecular recognition assays can be performed and analyzed. Cell microarrays (CMAs) make use of similar construction principles. They are applied to profile a given cell population with respect to the expression of specific molecular markers and also to measure functional cell responses to drugs and chemicals. This review focuses on the use of cell-based microarrays for assessing the cytotoxicity of drugs, toxins, or chemicals in general. It also summarizes CMA construction principles with respect to the cell types that are used for such microarrays, the readout parameters to assess toxicity, and the various formats that have been established and applied. The review ends with a critical comparison of CMAs and well-established microtiter plate (MTP) approaches.
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Affiliation(s)
- Joachim Wegener
- Institute for Analytical Chemistry, University of Regensburg, D-93053 Regensburg, Germany;
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Martins SAM, Trabuco JRC, Monteiro GA, Chu V, Conde JP, Prazeres DMF. Towards the miniaturization of GPCR-based live-cell screening assays. Trends Biotechnol 2012; 30:566-74. [PMID: 22921755 DOI: 10.1016/j.tibtech.2012.07.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 07/23/2012] [Accepted: 07/24/2012] [Indexed: 01/13/2023]
Abstract
G protein-coupled receptors (GPCRs) play a key role in many physiological or disease-related processes and for this reason are favorite targets of the pharmaceutical industry. Although ~30% of marketed drugs target GPCRs, their potential remains largely untapped. The discovery of new leads calls for the screening of thousands of compounds with high-throughput cell-based assays. Although microtiter plate-based high-throughput screening platforms are well established, microarray and microfluidic technologies hold potential for miniaturization, automation, and biosensor integration that may well redefine the format of GPCR screening assays. This paper reviews the latest research efforts directed to bringing microarray and microfluidic technologies into the realm of GPCR-based, live-cell screening assays.
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Affiliation(s)
- Sofia A M Martins
- IBB-Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Department of Bioengineering, Instituto Superior Técnico, Technical University of Lisbon, 1049-001 Lisbon, Portugal
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Evenou F, Di Meglio JM, Ladoux B, Hersen P. Micro-patterned porous substrates for cell-based assays. LAB ON A CHIP 2012; 12:1717-22. [PMID: 22434338 DOI: 10.1039/c2lc20696j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In the search for new therapeutic chemicals, lab-on-a-chip systems have recently emerged as innovative and efficient tools for cell-based assays and high throughput screening. Here, we describe a novel, versatile and simple device for cell-based assays at the bench-top. We created spatial variations of porosity on the surface of a membrane filter by microcontact printing with a biocompatible polymer (PDMS). We called such systems Micro-Printed Membranes (μPM). Active compounds dispensed on the porous areas, where the membrane pores are not clogged by the polymer, can cross the membrane and reach cells growing on the opposite side. Only cells immediately below those porous areas could be stimulated by chemicals. We performed proof-of-principle experiments using Hoechst nuclear staining, calcein-AM cell viability assay and destabilization of the cytoskeleton organisation by cytochalasin B. Resulting fluorescent staining properly matched the drops positioning and no cross-contaminations were observed between adjacent tests. This well-less cell-based screening system is highly flexible by design and it enables multiple compounds to be tested on the same cell tissue. Only low sample volumes in the microlitre range are required. Moreover, chemicals can be delivered sequentially and removed at any time while cells can be monitored in real time. This allows the design of complex, sequential and combinatorial drug assays. μPMs appear as ideal systems for cell-based assays. We anticipate that this lab-on-chip device will be adapted for both manual and automated high content screening experiments.
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Affiliation(s)
- Fanny Evenou
- Matière et Systèmes Complexes, UMR 7057 CNRS & Université Paris Diderot, 75013 Paris, France
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Fernandes TG, Diogo MM, Clark DS, Dordick JS, Cabral JMS. High-throughput cellular microarray platforms: applications in drug discovery, toxicology and stem cell research. Trends Biotechnol 2009; 27:342-9. [PMID: 19398140 DOI: 10.1016/j.tibtech.2009.02.009] [Citation(s) in RCA: 216] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Revised: 02/13/2009] [Accepted: 02/18/2009] [Indexed: 02/08/2023]
Abstract
Cellular microarrays are powerful experimental tools for high-throughput screening of large numbers of test samples. Miniaturization increases assay throughput while reducing reagent consumption and the number of cells required, making these systems attractive for a wide range of assays in drug discovery, toxicology, stem cell research and potentially therapy. Here, we provide an overview of the emerging technologies that can be used to generate cellular microarrays, and we highlight recent significant advances in the field. This emerging and multidisciplinary approach offers new opportunities for the design and control of stem cells in tissue engineering and cellular therapies and promises to expedite drug discovery in the biotechnology and pharmaceutical industries.
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Affiliation(s)
- Tiago G Fernandes
- Institute for Biotechnology and Bioengineering (IBB), Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
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Li J, Zhang T, Ge J, Yin Y, Zhong W. Fluorescence Signal Amplification by Cation Exchange in Ionic Nanocrystals. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200805710] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Li J, Zhang T, Ge J, Yin Y, Zhong W. Fluorescence Signal Amplification by Cation Exchange in Ionic Nanocrystals. Angew Chem Int Ed Engl 2009; 48:1588-91. [DOI: 10.1002/anie.200805710] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Gilchrist A. A perspective on more effective GPCR-targeted drug discovery efforts. Expert Opin Drug Discov 2008; 3:375-89. [DOI: 10.1517/17460441.3.4.375] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Underhill GH, Bhatia SN. High-throughput analysis of signals regulating stem cell fate and function. Curr Opin Chem Biol 2007; 11:357-66. [PMID: 17656147 PMCID: PMC2824500 DOI: 10.1016/j.cbpa.2007.05.036] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Accepted: 05/29/2007] [Indexed: 11/26/2022]
Abstract
Stem cells exhibit promise in numerous areas of regenerative medicine. Their fate and function are governed by a combination of intrinsic determinants and signals from the local microenvironment, or niche. An understanding of the mechanisms underlying both embryonic and adult stem cell functions has been greatly enhanced by the recent development of several high-throughput technologies: microfabricated platforms, including cellular microarrays, to investigate the combinatorial effects of microenvironmental stimuli and large-scale screens utilizing small molecules and short interfering RNAs to identify crucial genetic and signaling elements. Furthermore, the integration of these systems with other versatile platforms, such as microfluidics and lentiviral microarrays, will continue to enable the detailed elucidation of stem cell processes, and thus, greatly contribute to the development of stem cell based therapies.
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Affiliation(s)
- Gregory H. Underhill
- Harvard–M.I.T. Division of Health Sciences and Technology / Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Ave., E19-502D, Cambridge, MA, USA
| | - Sangeeta N. Bhatia
- Harvard–M.I.T. Division of Health Sciences and Technology / Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Ave., E19-502D, Cambridge, MA, USA
- Division of Medicine, Brigham and Women’s Hospital, Boston, MA, USA
- Corresponding author. Tel.: +1 617 324-0221; Fax: +1 617 324-0740;
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Affiliation(s)
- Daniel P Walsh
- Department of Chemistry, New York University, New York, New York 10003, USA
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Ma H, Horiuchi KY. Chemical microarray: a new tool for drug screening and discovery. Drug Discov Today 2007; 11:661-8. [PMID: 16793536 PMCID: PMC2577215 DOI: 10.1016/j.drudis.2006.05.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Revised: 04/07/2006] [Accepted: 05/10/2006] [Indexed: 11/30/2022]
Abstract
HTS with microtiter plates has been the major tool used in the pharmaceutical industry to explore chemical diversity space and to identify active compounds and pharmacophores for specific biological targets. However, HTS faces a daunting challenge regarding the fast-growing numbers of drug targets arising from genomic and proteomic research, and large chemical libraries generated from high-throughput synthesis. There is an urgent need to find new ways to profile the activity of large numbers of chemicals against hundreds of biological targets in a fast, low-cost fashion. Chemical microarray can rise to this challenge because it has the capability of identifying and evaluating small molecules as potential therapeutic reagents. During the past few years, chemical microarray technology, with different surface chemistries and activation strategies, has generated many successes in the evaluation of chemical–protein interactions, enzyme activity inhibition, target identification, signal pathway elucidation and cell-based functional analysis. The success of chemical microarray technology will provide unprecedented possibilities and capabilities for parallel functional analysis of tremendous amounts of chemical compounds.
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Affiliation(s)
- Haiching Ma
- Reaction Biology Corporation, One Great Valley Parkway, Suite 8, Malvern, PA 19355, USA.
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Nicholson RL, Welch M, Ladlow M, Spring DR. Small-molecule screening: advances in microarraying and cell-imaging technologies. ACS Chem Biol 2007; 2:24-30. [PMID: 17243780 DOI: 10.1021/cb600321j] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cell-permeable small molecules can be used to modulate protein function selectively, rapidly, reversibly, and conditionally with temporal and quantitative control in biological systems. The identification of these chemical probes can require the screening of large numbers of small molecules. With the advent of new technologies, small-molecule high-throughput screening is widely available. This Review focuses on the emerging technologies of microarray screening platforms and high-content screening formats.
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Affiliation(s)
- Rebecca L Nicholson
- Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, United Kingdom
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Moreland RB. In vitro models: research in physiology and pharmacology of the lower urinary tract. Br J Pharmacol 2006; 147 Suppl 2:S56-61. [PMID: 16465184 PMCID: PMC1751497 DOI: 10.1038/sj.bjp.0706505] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The physiology and pharmacology of the lower urinary tract has advanced based, in part, due to the in vitro assays that have facilitated this exploration. Such assays have led to the development of novel and selective molecules that have been used to characterize different receptor and enzyme systems in the larger context of in vivo pharmacology. These assays can be classified by sites of action of drugs into the following categories: receptors, effector enzymes and enzymes that terminate the responses. In this review, representative assays are presented based on our experience in male erectile dysfunction.
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MESH Headings
- Animals
- Binding, Competitive
- Cells, Cultured
- Drug Evaluation, Preclinical/methods
- Enzyme-Linked Immunosorbent Assay
- Erectile Dysfunction/drug therapy
- Erectile Dysfunction/metabolism
- Erectile Dysfunction/physiopathology
- Humans
- Ion Channels/metabolism
- Ligands
- Male
- Muscle Contraction/drug effects
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Penis/blood supply
- Penis/drug effects
- Penis/metabolism
- Radioimmunoassay
- Radioligand Assay
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Signal Transduction/drug effects
- Transfection
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Affiliation(s)
- Robert B Moreland
- Neuroscience Research, Global Pharmaceutical Research and Discovery, Department R4PM, Abbott Laboratories, Abbott Park, IL 60064-6123, USA.
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Moreland RB, Patel M, Hsieh GC, Wetter JM, Marsh K, Brioni JD. A-412997 is a selective dopamine D4 receptor agonist in rats. Pharmacol Biochem Behav 2005; 82:140-7. [PMID: 16153699 DOI: 10.1016/j.pbb.2005.08.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2005] [Revised: 07/15/2005] [Accepted: 08/08/2005] [Indexed: 11/18/2022]
Abstract
A-412997 (2-(3',4',5',6'-tetrahydro-2'H-[2,4'] bipyridinyl-1'-yl)-N-m-tolyl-acetamide) is a highly selective dopamine D4 receptor agonist that binds with high affinity to rat dopamine D4 and human dopamine D4.4 receptors (Ki=12.1 and 7.9 nM, respectively). In contrast to the dopamine D4 receptor agonists PD168077 and CP226269, A-412997 showed a better selectivity profile and no affinity <1000 nM for other dopamine receptors or any other proteins in a panel of seventy different receptors and channels. In functional assays using calcium flux, A-412997 was a potent full agonist at rat dopamine D4 receptors (28.4 nM, intrinsic activity=0.83) and did not activate rat dopamine D2L receptors, unlike CP226269. Dopamine D4 receptor selective agonists have been shown to induce penile erection in rats by central mechanisms. A-412997 induces penile erection in a conscious rat model (effective dose=0.1 micromol/kg, s.c.) with comparable efficacy as the nonselective D2-like agonist, apomorphine. When dosed systemically, A-412997 crossed the blood brain barrier rapidly and achieved significantly higher levels than PD168077. A-412997 is a highly selective dopamine D4 receptor agonist and a useful tool to understand the role of dopamine D4 receptors in rat models of central nervous system processes and disease.
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Affiliation(s)
- Robert B Moreland
- Neuroscience Research, Global Pharmaceutical Research and Development, AP9A Room 219, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, Illinois, 60064-6123, USA.
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15
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Moreland RB, Nakane M, Donnelly-Roberts DL, Miller LN, Chang R, Uchic ME, Terranova MA, Gubbins EJ, Helfrich RJ, Namovic MT, El-Kouhen OF, Masters JN, Brioni JD. Comparative pharmacology of human dopamine D(2)-like receptor stable cell lines coupled to calcium flux through Galpha(qo5). Biochem Pharmacol 2004; 68:761-72. [PMID: 15276084 DOI: 10.1016/j.bcp.2004.05.019] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2003] [Accepted: 05/11/2004] [Indexed: 11/23/2022]
Abstract
The goal of this study was to develop a new approach to study the pharmacology of the dopamine D(4) receptor that could be used in comparative studies with dopamine D(2) and D(3) receptors. Stable HEK-293 cell lines co-expressing recombinant human D(2L), D(3) or D(4) receptors along with Galpha(qo5) cDNA were prepared. Dopamine induced a robust, transient calcium signal in these cell lines with EC(50)s for D(2L), D(3) and D(4) of 18.0, 11.9 and 2.2 nM, respectively. Reported D(4)-selective agonists CP226269 and PD168077 were potent, partial D(4) agonists exhibiting 31-1700-fold selectivity for D(4) over D(3) or D(2). Non-selective D(2)-like agonists apomorphine and quinpirole showed full efficacy but did not discriminate across the three receptors. D(3)-selective agonists 7-hydroxy-DPAT and PD128907 were potent but non-selective D(2)-like agonists. The reported D(3) partial agonist BP-897 exhibited minimal agonist activity at D(3) but was a potent D(3) antagonist and a partial D(4) agonist. Other D(2)-like antagonists, haloperidol, clozapine, and domperidone showed concentration-dependent inhibition of dopamine responses at all three receptors with K(i) ranging from 0.05 to 48.3 nM. The D(3) selective antagonist S33084 and D(4)-selective antagonist L-745870 were highly selective for D(3) and D(4) receptors with K(b) of 0.7 and 0.1 nM, respectively. Stable co-expression of D(2)-like receptors with chimeric Galpha(qo5) proteins in HEK-293 cells is an efficient method to study receptor activation in a common cellular background and an efficient method for direct comparison of ligand affinity and efficacy across human D(2L), D(3) and D(4) receptors.
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Affiliation(s)
- Robert B Moreland
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, IL 60064, USA.
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Abstract
This review describes recent developments in the evolutionary process of microarrayed compound screening (microARCS to become a robust and efficient ultra-high-throughput screening technology. Improvements in compound spotting (including new quality-control methods), gel casting and imaging, together with software capable of automatic analysis and deconvolution of images, have helped to streamline the screening process. A variety of screening projects using cell-based and non-cell-based approaches have been successfully concluded using microARCS. Comparison of hits derived from standard microtitre-plate-based screening and from microARCS reveals excellent overlap. Furthermore, there seems to be no bias towards finding compounds within a particular range of logP values, even though compounds are solubilized from a dry state during the course of the assay.
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Affiliation(s)
- Michael Hoever
- Discovery Partners International AG, Gewerbestrasse 16, CH-4123 Allschwil, Switzerland.
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Stewart AO, Cowart MD, Moreland RB, Latshaw SP, Matulenko MA, Bhatia PA, Wang X, Daanen JF, Nelson SL, Terranova MA, Namovic MT, Donnelly-Roberts DL, Miller LN, Nakane M, Sullivan JP, Brioni JD. Dopamine D4 Ligands and Models of Receptor Activation: 2-(4-Pyridin-2-ylpiperazin-1-ylmethyl)-1H-benzimidazole and Related Heteroarylmethylarylpiperazines Exhibit a Substituent Effect Responsible for Additional Efficacy Tuning. J Med Chem 2004; 47:2348-55. [PMID: 15084133 DOI: 10.1021/jm0305669] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of subtype selective dopamine D(4) receptor ligands from the hetroarylmethylphenylpiperazine class have been discovered that exhibit a remarkable structure-activity relationship (SAR), revealing a substituent effect in which regiosubstitution on the terminal arylpiperazine ring can modulate functional or intrinsic activity. Other structure-dependent efficacy studies in the dopamine D(4) field have suggested a critical interaction of the heteroarylmethyl moiety with specific protein microdomains in controlling intrinsic activity. Our studies indicate that for some binding orientations, the phenylpiperazine moiety also plays a key role in determining efficacy. These data also implicate a kinetic or efficiency term, contained within measured functional affinities for agonists, which support a sequential binding and conformational stabilization model for receptor activation. The structural similarity between partial agonist and antagonist, within this subset of ligands, and lack of bioisosterism for this substituent effect are key phenomena for these hypotheses.
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Affiliation(s)
- Andrew O Stewart
- Department R4ND, Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, Illinois 60064-6115, USA.
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