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Mining the Potential of Label-Free Biosensors for Seven-Transmembrane Receptor Drug Discovery. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 115:123-42. [DOI: 10.1016/b978-0-12-394587-7.00003-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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102
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Jin J, Sison K, Li C, Tian R, Wnuk M, Sung HK, Jeansson M, Zhang C, Tucholska M, Jones N, Kerjaschki D, Shibuya M, Fantus IG, Nagy A, Gerber HP, Ferrara N, Pawson T, Quaggin SE. Soluble FLT1 binds lipid microdomains in podocytes to control cell morphology and glomerular barrier function. Cell 2012; 151:384-99. [PMID: 23063127 DOI: 10.1016/j.cell.2012.08.037] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2012] [Revised: 08/02/2012] [Accepted: 08/31/2012] [Indexed: 01/06/2023]
Abstract
Vascular endothelial growth factor and its receptors, FLK1/KDR and FLT1, are key regulators of angiogenesis. Unlike FLK1/KDR, the role of FLT1 has remained elusive. FLT1 is produced as soluble (sFLT1) and full-length isoforms. Here, we show that pericytes from multiple tissues produce sFLT1. To define the biologic role of sFLT1, we chose the glomerular microvasculature as a model system. Deletion of Flt1 from specialized glomerular pericytes, known as podocytes, causes reorganization of their cytoskeleton with massive proteinuria and kidney failure, characteristic features of nephrotic syndrome in humans. The kinase-deficient allele of Flt1 rescues this phenotype, demonstrating dispensability of the full-length isoform. Using cell imaging, proteomics, and lipidomics, we show that sFLT1 binds to the glycosphingolipid GM3 in lipid rafts on the surface of podocytes, promoting adhesion and rapid actin reorganization. sFLT1 also regulates pericyte function in vessels outside of the kidney. Our findings demonstrate an autocrine function for sFLT1 to control pericyte behavior.
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Affiliation(s)
- Jing Jin
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
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103
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Guo D, Mulder-Krieger T, IJzerman AP, Heitman LH. Functional efficacy of adenosine A₂A receptor agonists is positively correlated to their receptor residence time. Br J Pharmacol 2012; 166:1846-59. [PMID: 22324512 DOI: 10.1111/j.1476-5381.2012.01897.x] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND AND PURPOSE The adenosine A(2A) receptor belongs to the superfamily of GPCRs and is a promising therapeutic target. Traditionally, the discovery of novel agents for the A(2A) receptor has been guided by their affinity for the receptor. This parameter is determined under equilibrium conditions, largely ignoring the kinetic aspects of the ligand-receptor interaction. The aim of this study was to assess the binding kinetics of A(2A) receptor agonists and explore a possible relationship with their functional efficacy. EXPERIMENTAL APPROACH We set up, validated and optimized a kinetic radioligand binding assay (a so-called competition association assay) at the A(2A) receptor from which the binding kinetics of unlabelled ligands were determined. Subsequently, functional efficacies of A(2A) receptor agonists were determined in two different assays: a novel label-free impedance-based assay and a more traditional cAMP determination. KEY RESULTS A simplified competition association assay yielded an accurate determination of the association and dissociation rates of unlabelled A(2A) receptor ligands at their receptor. A correlation was observed between the receptor residence time of A(2A) receptor agonists and their intrinsic efficacies in both functional assays. The affinity of A(2A) receptor agonists was not correlated to their functional efficacy. CONCLUSIONS AND IMPLICATIONS This study indicates that the molecular basis of different agonist efficacies at the A(2A) receptor lies within their different residence times at this receptor.
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Affiliation(s)
- Dong Guo
- Division of Medicinal Chemistry, Leiden/Amsterdam Centre for Drug Research, Leiden University, Leiden, the Netherlands
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104
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Inflammatory effects of resistin on human smooth muscle cells: up-regulation of fractalkine and its receptor, CX3CR1 expression by TLR4 and Gi-protein pathways. Cell Tissue Res 2012; 351:161-74. [PMID: 23086480 DOI: 10.1007/s00441-012-1510-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 09/20/2012] [Indexed: 10/27/2022]
Abstract
In the atherosclerotic plaque, smooth muscle cells (SMC) acquire an inflammatory phenotype. Resistin and fractalkine (CX3CL1) are found in human atheroma and not in normal arteries. CX3CL1 and CX3CR1 are predominately associated with SMC. We have questioned whether resistin has a role in the expression of CX3CL1 and CX3CR1 in SMC thus contributing to the pro-inflammatory status of these cells. Cultured human aortic SMC were stimulated with 100 ng/ml resistin for 4, 6, 12, and 24 h, and then CX3CL1 and CX3CR1 expression was assessed by quantitative reverse transcription with the polymerase chain reaction and Western blot. We found that resistin up-regulated CX3CL1 and CX3CR1 in SMC and induced the phosphorylation of p38MAPK and STAT3. Inhibitors of p38MAPK, JAK-STAT, NF-kB, and AP-1 significantly reduced CX3CL1 and CX3CR1 expression. Knockdown of STAT1 and STAT3 with decoy oligodeoxinucleotides and the silencing of p65 and cjun with short interfering RNA decreased CX3CL1 and CX3CR1 expression. Anti-TLR4 antibody and pertussis toxin also reduced CX3CL1 and CX3CR1 protein expression. xCELLigence experiments revealed that resistin probably uses Gi-proteins for its effect on SMC. The CX3CL1 induced by resistin exhibited a chemotactic effect on monocyte transmigration. Thus, (1) resistin contributes to the pro-inflammatory state of SMC by the up-regulation of CX3CL1 and CX3CR1 expression via a mechanism involving NF-kB, AP-1, and STAT1/3 transcription factors, (2) resistin employs TLR4 and Gi-protein signaling for its effect on SMC, (3) CX3CL1 induced by resistin is functional in monocyte chemotaxis. The data reveal new mechanisms by which resistin promotes the inflammatory phenotype of SMC.
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105
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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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106
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Mechaly A, Levy H, Epstein E, Rosenfeld R, Marcus H, Ben-Arie E, Shafferman A, Ordentlich A, Mazor O. A novel mechanism for antibody-based anthrax toxin neutralization: inhibition of prepore-to-pore conversion. J Biol Chem 2012; 287:32665-73. [PMID: 22869370 DOI: 10.1074/jbc.m112.400473] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Protective antigen (PA), a key component of anthrax toxin, mediates the entry of lethal factor (LF) or edema factor (EF) through a membranal pore into target cells. We have previously reported the isolation and chimerization of cAb29, an anti-PA monoclonal antibody that effectively neutralizes anthrax toxin in an unknown mechanism. The aim of this study was to elucidate the neutralizing mechanism of this antibody in vitro and to test its ability to confer post-exposure protection against anthrax in vivo. By systematic evaluation of the steps taking place during the PA-based intoxication process, we found that cAb29 did not interfere with the initial steps of intoxication, namely its ability to bind to the anthrax receptor, the consecutive proteolytic cleavage to PA(63), oligomerization, prepore formation, or LF binding. However, the binding of cAb29 to the prepore prevented its pH-triggered transition to the transmembranal pore, thus preventing the last step of intoxication, i.e. the translocation of LF/EF into the cell. Epitope mapping, using a phage display peptide library, revealed that cAb29 binds the 2α(1) loop in domain 2 of PA, a loop that undergoes major conformational changes during pore formation. In vivo, we found that 100% of anthrax-infected rabbits survived when treated with cAb29 12 h after exposure. In conclusion, these experiments demonstrate that cAb29 exerts its potent neutralizing activity in a unique manner by blocking the prepore-to-pore conversion process.
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Affiliation(s)
- Adva Mechaly
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness-Ziona 74100, Israel
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107
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Sun M, Fu H, Cheng H, Cao Q, Zhao Y, Mou X, Zhang X, Liu X, Ke Y. A dynamic real-time method for monitoring epithelial barrier function in vitro. Anal Biochem 2012; 425:96-103. [DOI: 10.1016/j.ab.2012.03.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 03/08/2012] [Accepted: 03/16/2012] [Indexed: 02/07/2023]
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108
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Zhang Y, Wang H, Wang L, Cheng J. Real-Time, Label-Free Monitoring of 3T3-L1 Preadipocyte Differentiation by a Bioelectrical Impedance Assay. ANAL LETT 2012. [DOI: 10.1080/00032719.2012.670791] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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109
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Microfabricated electrochemical cell-based biosensors for analysis of living cells in vitro. BIOSENSORS-BASEL 2012; 2:127-70. [PMID: 25585708 PMCID: PMC4263572 DOI: 10.3390/bios2020127] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 04/02/2012] [Accepted: 04/19/2012] [Indexed: 01/03/2023]
Abstract
Cellular biochemical parameters can be used to reveal the physiological and functional information of various cells. Due to demonstrated high accuracy and non-invasiveness, electrochemical detection methods have been used for cell-based investigation. When combined with improved biosensor design and advanced measurement systems, the on-line biochemical analysis of living cells in vitro has been applied for biological mechanism study, drug screening and even environmental monitoring. In recent decades, new types of miniaturized electrochemical biosensor are emerging with the development of microfabrication technology. This review aims to give an overview of the microfabricated electrochemical cell-based biosensors, such as microelectrode arrays (MEA), the electric cell-substrate impedance sensing (ECIS) technique, and the light addressable potentiometric sensor (LAPS). The details in their working principles, measurement systems, and applications in cell monitoring are covered. Driven by the need for high throughput and multi-parameter detection proposed by biomedicine, the development trends of electrochemical cell-based biosensors are also introduced, including newly developed integrated biosensors, and the application of nanotechnology and microfluidic technology.
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110
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Wilson JL, Taylor L, Polgar P. Endothelin-1 activation of ETB receptors leads to a reduced cellular proliferative rate and an increased cellular footprint. Exp Cell Res 2012; 318:1125-33. [PMID: 22504006 DOI: 10.1016/j.yexcr.2012.03.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 03/26/2012] [Accepted: 03/28/2012] [Indexed: 10/28/2022]
Abstract
Endothelin-1 (ET-1) is a vasoactive peptide which signals through two G-protein coupled receptors, endothelin receptor A (ETA) and B (ETB). We determined that ET-1 activation of its ETB receptor in stably cDNA transfected CHO cells leads to a 55% reduction in cell number by end-point cell counting and a 35% decrease in cell growth by a real-time cell-substrate impedance-based assay after 24h of cell growth. When CHO ETB cells were synchronized in the late G1 cell cycle phase, ET-1 delayed their S phase progression compared to control by 30% as determined by [(3)H]-thymidine incorporation. On the other hand, no such delay was observed during late G2/M to G1 transit when cells were treated with ET-1 after release from mitotic arrest. Using the cell-substrate impedance-based assay, we observed that ET-1 induces opposing morphological changes in CHO ETA and CHO ETB cells with ETB causing an increase in the cell footprint and ETA a decrease. Likewise, in pulmonary artery smooth muscle cells, which express both ETA and ETB receptors, ET-1 induces an ETA-dependent contraction and an ETB dependent dilation. These results are shedding light on a possible beneficial role for ETB in diseases involving ET-1 dysfunction such as pulmonary hypertension.
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Affiliation(s)
- Jamie L Wilson
- Department of Biochemistry, Boston University School of Medicine, 72 E. Concord Street, Boston, MA 02118, USA
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111
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Resolvin D1 receptor stereoselectivity and regulation of inflammation and proresolving microRNAs. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 180:2018-27. [PMID: 22449948 DOI: 10.1016/j.ajpath.2012.01.028] [Citation(s) in RCA: 199] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 01/18/2012] [Accepted: 01/24/2012] [Indexed: 01/17/2023]
Abstract
Resolution of acute inflammation is an active process that involves the biosynthesis of specialized proresolving lipid mediators. Among them, resolvin D1 (RvD1) actions are mediated by two G protein-coupled receptors (GPCRs), ALX/FPR2 and GPR32, that also regulate specific microRNAs (miRNAs) and their target genes in novel resolution circuits. We report the ligand selectivity of RvD1 activation of ALX/FPR2 and GPR32. In addition to RvD1, its aspirin-triggered epimer and RvD1 analogs each dose dependently and effectively activated ALX/FPR2 and GPR32 in GPCR-overexpressing β-arrestin systems using luminescence and electric cell-substrate impedance sensing. To corroborate these findings in vivo, neutrophil infiltration in self-limited peritonitis was reduced in human ALX/FPR2-overexpressing transgenic mice that was further limited to 50% by RvD1 treatment with as little as 10 ng of RvD1 per mouse. Analysis of miRNA expression revealed that RvD1 administration significantly up-regulated miR-208a and miR-219 in exudates isolated from ALX/FPR2 transgenic mice compared with littermates. Overexpression of miR-208a in human macrophages up-regulated IL-10. In comparison, in ALX/FPR2 knockout mice, RvD1 neither significantly reduced leukocyte infiltration in zymosan-induced peritonitis nor regulated miR-208a and IL-10 in these mice. Together, these results demonstrate the selectivity of RvD1 interactions with receptors ALX/FPR2 and GPR32. Moreover, they establish a new molecular circuit that is operative in the resolution of acute inflammation activated by the proresolving mediator RvD1 involving specific GPCRs and miRNAs.
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112
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Abdolahad M, Taghinejad M, Taghinejad H, Janmaleki M, Mohajerzadeh S. A vertically aligned carbon nanotube-based impedance sensing biosensor for rapid and high sensitive detection of cancer cells. LAB ON A CHIP 2012; 12:1183-1190. [PMID: 22294045 DOI: 10.1039/c2lc21028b] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A novel vertically aligned carbon nanotube based electrical cell impedance sensing biosensor (CNT-ECIS) was demonstrated for the first time as a more rapid, sensitive and specific device for the detection of cancer cells. This biosensor is based on the fast entrapment of cancer cells on vertically aligned carbon nanotube arrays and leads to mechanical and electrical interactions between CNT tips and entrapped cell membranes, changing the impedance of the biosensor. CNT-ECIS was fabricated through a photolithography process on Ni/SiO(2)/Si layers. Carbon nanotube arrays have been grown on 9 nm thick patterned Ni microelectrodes by DC-PECVD. SW48 colon cancer cells were passed over the surface of CNT covered electrodes to be specifically entrapped on elastic nanotube beams. CNT arrays act as both adhesive and conductive agents and impedance changes occurred as fast as 30 s (for whole entrapment and signaling processes). CNT-ECIS detected the cancer cells with the concentration as low as 4000 cells cm(-2) on its surface and a sensitivity of 1.7 × 10(-3)Ω cm(2). Time and cell efficiency factor (TEF and CEF) parameters were defined which describe the sensor's rapidness and resolution, respectively. TEF and CEF of CNT-ECIS were much higher than other cell based electrical biosensors which are compared in this paper.
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Affiliation(s)
- Mohammad Abdolahad
- Nano-Electronics and Thin Film Laboratory, School of Electrical and Computer Engineering, University of Tehran, Tehran, Iran
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113
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Watts AO, Scholten DJ, Heitman LH, Vischer HF, Leurs R. Label-free impedance responses of endogenous and synthetic chemokine receptor CXCR3 agonists correlate with Gi-protein pathway activation. Biochem Biophys Res Commun 2012; 419:412-8. [DOI: 10.1016/j.bbrc.2012.02.036] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 02/05/2012] [Indexed: 01/13/2023]
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114
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Abstract
G-protein-coupled receptors (GPCRs) mediate many important physiological functions and
are considered as one of the most successful therapeutic targets for a broad spectrum of
diseases. The design and implementation of high-throughput GPCR assays that allow the
cost-effective screening of large compound libraries to identify novel drug candidates are
critical in early drug discovery. Early functional GPCR assays depend primarily on the
measurement of G-protein-mediated 2nd messenger generation. Taking advantage of the
continuously deepening understanding of GPCR signal transduction, many
G-protein-independent pathways are utilized to detect the activity of GPCRs, and may
provide additional information on functional selectivity of candidate compounds. With the
combination of automated imaging systems and label-free detection systems, such assays are
now suitable for high-throughput screening (HTS). In this review, we summarize the most
widely used GPCR assays and recent advances in HTS technologies for GPCR drug
discovery.
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115
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Seiffert JM, Baradez MO, Nischwitz V, Lekishvili T, Goenaga-Infante H, Marshall D. Dynamic monitoring of metal oxide nanoparticle toxicity by label free impedance sensing. Chem Res Toxicol 2012; 25:140-52. [PMID: 22054034 DOI: 10.1021/tx200355m] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The increased use of nanoparticles in industrial and medical products is driving the need for accurate, high throughput in vitro testing procedures to screen new particles for potential toxicity. While approaches using standard viability assays have been widely used, there have been increased reports of the interactions of nanoparticles with their soluble labels or optical readouts which raise concerns over the potential generation of false positive results. Here, we describe the use of an impedance spectroscopy approach to provide real-time reagent free detection of toxicity for a panel of metal oxide nanoparticles (ZnO, CuO, and TiO(2)). Using this approach, we show how impedance measurements can be used to track nanoparticle toxicity over time with comparable IC(50) values to those of standard assays (ZnO-55 μg/mL, CuO-28 μg/mL) as well as being used to identify a critical 6 h period following exposure during which the nanoparticles trigger rapid cellular responses. Through targeted analysis during this response period and the use of a novel image analysis approach, we show how the ZnO and CuO nanoparticles trigger the active export of intracellular glutathione via an increase in the activity of the ATP dependent MRP/1 efflux pumps. The loss of glutathione leads to increased production of reactive oxygen species which after 2.5 h triggers the cells to enter apoptosis resulting in a dose dependent cytotoxic response. This targeted testing strategy provides comprehensive information beyond that achieved with standard toxicity assays and indicates the potential for cell-nanoparticle interactions that could occur following in vivo exposure.
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Affiliation(s)
- Joanna M Seiffert
- LGC , Science and Technology Division, Queens Road, Teddington, Middlesex TW11 0LY, UK
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116
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Stallaert W, Dorn JF, van der Westhuizen E, Audet M, Bouvier M. Impedance responses reveal β₂-adrenergic receptor signaling pluridimensionality and allow classification of ligands with distinct signaling profiles. PLoS One 2012; 7:e29420. [PMID: 22242170 PMCID: PMC3252315 DOI: 10.1371/journal.pone.0029420] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Accepted: 11/28/2011] [Indexed: 01/14/2023] Open
Abstract
The discovery that drugs targeting a single G protein-coupled receptor (GPCR) can differentially modulate distinct subsets of the receptor signaling repertoire has created a challenge for drug discovery at these important therapeutic targets. Here, we demonstrate that a single label-free assay based on cellular impedance provides a real-time integration of multiple signaling events engaged upon GPCR activation. Stimulation of the β2-adrenergic receptor (β2AR) in living cells with the prototypical agonist isoproterenol generated a complex, multi-featured impedance response over time. Selective pharmacological inhibition of specific arms of the β2AR signaling network revealed the differential contribution of Gs-, Gi- and Gβγ-dependent signaling events, including activation of the canonical cAMP and ERK1/2 pathways, to specific components of the impedance response. Further dissection revealed the essential role of intracellular Ca2+ in the impedance response and led to the discovery of a novel β2AR-promoted Ca2+ mobilization event. Recognizing that impedance responses provide an integrative assessment of ligand activity, we screened a collection of β-adrenergic ligands to determine if differences in the signaling repertoire engaged by compounds would lead to distinct impedance signatures. An unsupervised clustering analysis of the impedance responses revealed the existence of 5 distinct compound classes, revealing a richer signaling texture than previously recognized for this receptor. Taken together, these data indicate that the pluridimensionality of GPCR signaling can be captured using integrative approaches to provide a comprehensive readout of drug activity.
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Affiliation(s)
- Wayne Stallaert
- Department of Biochemistry, Université de Montréal, Montréal, Quebec, Canada
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada
| | - Jonas F. Dorn
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada
| | - Emma van der Westhuizen
- Department of Biochemistry, Université de Montréal, Montréal, Quebec, Canada
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada
| | - Martin Audet
- Department of Biochemistry, Université de Montréal, Montréal, Quebec, Canada
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada
| | - Michel Bouvier
- Department of Biochemistry, Université de Montréal, Montréal, Quebec, Canada
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada
- * E-mail:
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117
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Abstract
INTRODUCTION The need to improve drug research and development productivity continues to drive innovation in pharmacological assays. Technologies that can leverage the advantages of both molecular and phenotypic assays would hold great promise for discovery of new medicines. AREAS COVERED This article briefly reviews current label-free platforms for cell-based assays and is primarily focused on fundamental aspects of these assays using dynamic mass redistribution technology as an example. The article also presents strategies for relating label-free profiles to molecular modes of actions of drugs. EXPERT OPINION Emerging evidence suggests that label-free cellular assays are phenotypic in nature, yet permit molecular mechanistic deconvolution. Together with unique competency in throughput, sensitivity and pathway coverages, label-free cellular assays allow users to screen drugs against endogenous receptors in native cells (including disease relevant primary cells) and determine the molecular modes of action of drug molecules. However, there are challenges for label-free in both basic research and drug discovery: the deconvolution of the cellular and molecular mechanisms for the biosensor signatures of receptor-drug interactions, new methodologies for data analysis and the development of new biosensor technologies. These challenges will need to be met for the wide adoption of these assays in drug discovery.
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Affiliation(s)
- Ye Fang
- Biochemical Technologies, Science and Technology Division, Corning, Inc. , Corning, NY 14831 , USA
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118
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Jonsson MKB, Wang QD, Becker B. Impedance-based detection of beating rhythm and proarrhythmic effects of compounds on stem cell-derived cardiomyocytes. Assay Drug Dev Technol 2011; 9:589-99. [PMID: 22085047 DOI: 10.1089/adt.2011.0396] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The xCELLigence real time cell analyzer Cardio system offers a new system for real-time cell analysis that measures impedance-based signals in a label-free noninvasive manner. The aim of this study was to test whether impedance readings are a useful tool to detect compound effects on beating frequency (beats per minute, bpm) and arrhythmias of human induced pluripotent stem cell- and a mouse embryonic stem cell-derived cardiomyocyte line (hiPSC-CM and mESC-CM, respectively). Baseline values for control wells were 45±3 and 179±6 bpm, respectively (n=6). Correspondingly, isoproterenol increased beating frequency by 77% and 71%, whereas carbachol decreased frequency by 11% and 100% (stopped in 5/6 mESC-CM wells). E-4031 decreased beating rate and caused arrhythmias in both cell types, however, more pronounced in the human iPSC-CMs. Amlodipine inhibited contractions in both models, and T-type calcium channel block strongly reduced beating rate and eventually stopped beating in mESC-CM but caused a smaller effect in hiPSC-CM. The results of this initial study show that, under the right conditions, the beating frequency of a monolayer of cells can be stably recorded over several days. Additionally, the system detects changes in beating frequency and amplitude caused by added reference compounds. This assay system has the potential to enable medium-throughput screening, but for implementation into routine daily work, extended validation, testing of additional batches of cardiomyocytes, and further assay optimization (e.g., frequency of media exchange, growth matrix, seeding density, age of cells after plating, and temperature control) will be needed.
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Affiliation(s)
- Malin K B Jonsson
- Department of Medical Physiology, Heart & Lungs Division, University Medical Center Utrecht, Utrecht, The Netherlands
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119
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Mou X, Wan S, Li Y, Zhang S, Sun M, Liu F, Fu H, Zhang X, Liu H, Cao Q, Ke Y, Xiang C. Phenotypic pattern-based assay for dynamically monitoring host cellular responses to Salmonella infections. PLoS One 2011; 6:e26544. [PMID: 22073171 PMCID: PMC3207827 DOI: 10.1371/journal.pone.0026544] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 09/28/2011] [Indexed: 12/12/2022] Open
Abstract
The interaction between mammalian host cells and bacteria is a dynamic process, and the underlying pathologic mechanisms are poorly characterized. Limited information describing the host-bacterial interaction is based mainly on studies using label-based endpoint assays that detect changes in cell behavior at a given time point, yielding incomplete information. In this paper, a novel, label-free, real-time cell-detection system based on electronic impedance sensor technology was adapted to dynamically monitor the entire process of intestinal epithelial cells response to Salmonella infection. Changes in cell morphology and attachment were quantitatively and continuously recorded following infection. The resulting impedance-based time-dependent cell response profiles (TCRPs) were compared to standard assays and showed good correlation and sensitivity. Biochemical assays further suggested that TCRPs were correlated with cytoskeleton-associated morphological dynamics, which can be largely attenuated by inhibitions of actin and microtubule polymerization. Collectively, our data indicate that cell-electrode impedance measurements not only provide a novel, real-time, label-free method for investigating bacterial infection but also help advance our understanding of host responses in a more physiological and continuous manner that is beyond the scope of current endpoint assays.
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Affiliation(s)
- Xiaozhou Mou
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Institute of Molecular Pathology and Program in Molecular Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
- Molecular Diagnosis Division, Zhejiang-California International Nanosystems Institute (ZCNI), Hangzhou, China
| | - Shuying Wan
- Institute of Molecular Pathology and Program in Molecular Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Yifei Li
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shanshan Zhang
- Institute of Molecular Pathology and Program in Molecular Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Mingjiao Sun
- Institute of Molecular Pathology and Program in Molecular Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Fanglong Liu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Huiying Fu
- Institute of Molecular Pathology and Program in Molecular Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Xue Zhang
- Institute of Molecular Pathology and Program in Molecular Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Haiying Liu
- State Key Laboratory for Molecular Virology and Genetic Engineering, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Qian Cao
- Institute of Molecular Pathology and Program in Molecular Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Yuehai Ke
- Institute of Molecular Pathology and Program in Molecular Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
- * E-mail: (YK); (CX)
| | - Charlie Xiang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Molecular Diagnosis Division, Zhejiang-California International Nanosystems Institute (ZCNI), Hangzhou, China
- * E-mail: (YK); (CX)
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Meshki J, Douglas SD, Hu M, Leeman SE, Tuluc F. Substance P induces rapid and transient membrane blebbing in U373MG cells in a p21-activated kinase-dependent manner. PLoS One 2011; 6:e25332. [PMID: 21966499 PMCID: PMC3179504 DOI: 10.1371/journal.pone.0025332] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Accepted: 09/01/2011] [Indexed: 11/18/2022] Open
Abstract
U373MG astrocytoma cells endogenously express the full-length neurokinin 1 receptor (NK1R). Substance P (SP), the natural ligand for NK1R, triggers rapid and transient membrane blebbing and we report that these morphological changes have different dynamics and intracellular signaling as compared to the changes that we have previously described in HEK293-NK1R cells. In both cell lines, the SP-induced morphological changes are Gq-independent, and they require the Rho, Rho-associated coiled-coil kinase (ROCK) signaling pathway. Using confocal microscopy we have demonstrated that tubulin is phosphorylated subsequent to cell stimulation with SP and that tubulin accumulates inside the blebs. Colchicine, a tubulin polymerization inhibitor, blocked SP-induced blebbing in U373MG but not in HEK293-NK1R cells. Although p21-activated kinase (PAK) is expressed in both cell lines, SP induced rapid phosphorylation of PAK in U373MG, but failed to phosphorylate PAK in HEK293-NK1R cells. The cell-permeable Rho inhibitor C3 transferase inhibited SP-induced PAK phosphorylation, but the ROCK inhibitor Y27632 had no effect on PAK phosphorylation, suggesting that Rho activates PAK in a ROCK-independent manner. Our study demonstrates that SP triggers rapid changes in cell morphology mediated by distinct intracellular signaling mechanisms in U373MG versus HEK293-NK1R cells.
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Affiliation(s)
- John Meshki
- Division of Allergy and Immunology, The Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania, United States of America
| | - Steven D. Douglas
- Division of Allergy and Immunology, The Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania, United States of America
- Department of Pediatrics, University of Pennsylvania Medical School, Philadelphia, Pennsylvania, United States of America
| | - Mingyue Hu
- Division of Allergy and Immunology, The Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania, United States of America
| | - Susan E. Leeman
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Florin Tuluc
- Division of Allergy and Immunology, The Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania, United States of America
- Department of Pediatrics, University of Pennsylvania Medical School, Philadelphia, Pennsylvania, United States of America
- Flow Cytometry Core Laboratory, The Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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121
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Impedance measurement: A new method to detect ligand-biased receptor signaling. Biochem Biophys Res Commun 2011; 412:419-24. [DOI: 10.1016/j.bbrc.2011.07.087] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Accepted: 07/20/2011] [Indexed: 01/14/2023]
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122
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Steinbach SK, El-Mounayri O, DaCosta RS, Frontini MJ, Nong Z, Maeda A, Pickering JG, Miller FD, Husain M. Directed differentiation of skin-derived precursors into functional vascular smooth muscle cells. Arterioscler Thromb Vasc Biol 2011; 31:2938-48. [PMID: 21852558 DOI: 10.1161/atvbaha.111.232975] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVE The goal of this study was to characterize the factors and conditions required for smooth muscle cell (SMC)-directed differentiation of Sox2(+) multipotent rat and human skin-derived precursors (SKPs) and to define whether they represent a source of fully functional vascular SMCs for applications in vivo. METHODS AND RESULTS We found that rat SKPs can differentiate almost exclusively into SMCs by reducing serum concentrations to 0.5% to 2% and plating them at low density. Human SKPs derived from foreskin required the addition of transforming growth factor-β1 or -β3 to differentiate into SMCs, but they did so even in the absence of serum. SMC formation was confirmed by quantitative reverse transcription-polymerase chain reaction, immunocytochemistry, and fluorescence-activated cell sorting, with increased expression of smoothelin-B and little to no expression of telokin or smooth muscle γ-actin, together indicating that SKPs differentiated into vascular rather than visceral SMCs. Rat and human SKP-derived SMCs were able to contract in vitro and also wrap around and support new capillary and larger blood vessel formation in angiogenesis assays in vivo. CONCLUSIONS SKPs are Sox2(+) progenitors that represent an attainable autologous source of stem cells that can be easily differentiated into functional vascular SMCs in defined serum-free conditions without reprogramming. SKPs represent a clinically viable cell source for potential therapeutic applications in neovascularization.
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123
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Fu H, Fu W, Sun M, Shou Q, Zhai Y, Cheng H, Teng L, Mou X, Li Y, Wan S, Zhang S, Xu Q, Zhang X, Wang J, Zhu J, Wang X, Xu X, Lv G, Jin L, Guo W, Ke Y. Kinetic Cellular Phenotypic Profiling: Prediction, Identification, and Analysis of Bioactive Natural Products. Anal Chem 2011; 83:6518-26. [DOI: 10.1021/ac201670e] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Huiying Fu
- Program in Molecular Cell Biology, Department of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Wenqing Fu
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Mingjiao Sun
- Program in Molecular Cell Biology, Department of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Qiyang Shou
- Zhejiang University of Traditional Chinese Medicine, Hangzhou 310053, China
| | - Yunyan Zhai
- Program in Molecular Cell Biology, Department of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Hongqiang Cheng
- Program in Molecular Cell Biology, Department of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Li Teng
- Program in Molecular Cell Biology, Department of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Xiaozhou Mou
- Program in Molecular Cell Biology, Department of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Yanwei Li
- Program in Molecular Cell Biology, Department of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Shuying Wan
- Program in Molecular Cell Biology, Department of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Shanshan Zhang
- Program in Molecular Cell Biology, Department of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Qinqin Xu
- Program in Molecular Cell Biology, Department of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Xue Zhang
- Program in Molecular Cell Biology, Department of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Jiucun Wang
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Jenny Zhu
- ACEA Biosciences Incorporated, San Diego, California 92126, United States
| | - Xiaobo Wang
- ACEA Biosciences Incorporated, San Diego, California 92126, United States
| | - Xiao Xu
- ACEA Biosciences Incorporated, San Diego, California 92126, United States
| | - Guiyuan Lv
- Zhejiang University of Traditional Chinese Medicine, Hangzhou 310053, China
| | - Li Jin
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Wensheng Guo
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai 200433, China
- Center for Clinical Epidemiology and Biostatistics, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Yuehai Ke
- Program in Molecular Cell Biology, Department of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
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124
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Justice C, Brix A, Freimark D, Kraume M, Pfromm P, Eichenmueller B, Czermak P. Process control in cell culture technology using dielectric spectroscopy. Biotechnol Adv 2011; 29:391-401. [DOI: 10.1016/j.biotechadv.2011.03.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 03/04/2011] [Accepted: 03/06/2011] [Indexed: 10/18/2022]
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125
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Stallaert W, Christopoulos A, Bouvier M. Ligand functional selectivity and quantitative pharmacology at G protein-coupled receptors. Expert Opin Drug Discov 2011; 6:811-25. [DOI: 10.1517/17460441.2011.586691] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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126
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White GE, McNeill E, Christou I, Channon KM, Greaves DR. Site-directed mutagenesis of the CC chemokine binding protein 35K-Fc reveals residues essential for activity and mutations that increase the potency of CC chemokine blockade. Mol Pharmacol 2011; 80:328-36. [PMID: 21586597 DOI: 10.1124/mol.111.071985] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Chemokines of the CC class are key mediators of monocyte recruitment and macrophage differentiation and have a well documented role in many inflammatory diseases. Blockade of chemokine activity is therefore an attractive target for anti-inflammatory therapy. 35K (vCCI) is a high-affinity chemokine binding protein expressed by poxviruses, which binds all human and murine CC chemokines, preventing their interaction with chemokine receptors. We developed an Fc-fusion protein of 35K with a modified human IgG1 Fc domain and expressed this construct in human embryonic kidney 293T cells. Purified 35K-Fc is capable of inhibiting CC chemokine-induced calcium flux, chemotaxis, and β-arrestin recruitment in primary macrophages and transfected cells. To elucidate the residues involved in chemokine neutralization, we performed site-directed mutagenesis of six key amino acids in 35K and expressed the mutant Fc-fusion proteins in vitro. We screened the mutants for their ability to block chemokine-induced β-arrestin recruitment in transfected cells and to inhibit primary macrophage signaling in an electric cell substrate impedance sensing assay. Using a sterile model of acute inflammation, zymosan-induced peritonitis, we confirmed that wild-type 35K-Fc can reduce monocyte recruitment, whereas one mutant (R89A) showed a more pronounced blockade of monocyte influx and another mutant (E143K) showed total loss of function. We believe that 35K-Fc will be a useful tool for exploring the role of CC chemokines in chronic inflammatory pathologies, and we have identified a higher potency form of the molecule that may have potential therapeutic applications in chronic inflammatory disease.
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Affiliation(s)
- Gemma E White
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE
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127
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Atienzar FA, Tilmant K, Gerets HH, Toussaint G, Speeckaert S, Hanon E, Depelchin O, Dhalluin S. The use of real-time cell analyzer technology in drug discovery: defining optimal cell culture conditions and assay reproducibility with different adherent cellular models. ACTA ACUST UNITED AC 2011; 16:575-87. [PMID: 21518825 DOI: 10.1177/1087057111402825] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The use of impedance-based label-free technology applied to drug discovery is nowadays receiving more and more attention. Indeed, such a simple and noninvasive assay that interferes minimally with cell morphology and function allows one to perform kinetic measurements and to obtain information on proliferation, migration, cytotoxicity, and receptor-mediated signaling. The objective of the study was to further assess the usefulness of a real-time cell analyzer (RTCA) platform based on impedance in the context of quality control and data reproducibility. The data indicate that this technology is useful to determine the best coating and cellular density conditions for different adherent cellular models including hepatocytes, cardiomyocytes, fibroblasts, and hybrid neuroblastoma/neuronal cells. Based on 31 independent experiments, the reproducibility of cell index data generated from HepG2 cells exposed to DMSO and to Triton X-100 was satisfactory, with a coefficient of variation close to 10%. Cell index data were also well reproduced when cardiomyocytes and fibroblasts were exposed to 21 compounds three times (correlation >0.91, p < 0.0001). The data also show that a cell index decrease is not always associated with cytotoxicity effects and that there are some confounding factors that can affect the analysis. Finally, another drawback is that the correlation analysis between cellular impedance measurements and classical toxicity endpoints has been performed on a limited number of compounds. Overall, despite some limitations, the RTCA technology appears to be a powerful and reliable tool in drug discovery because of the reasonable throughput, rapid and efficient performance, technical optimization, and cell quality control.
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128
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Rakhilin S, Turner G, Katz M, Warden R, Irelan J, Abassi YA, Glass DJ. Electrical Impedance as a Novel Biomarker of Myotube Atrophy and Hypertrophy. ACTA ACUST UNITED AC 2011; 16:565-74. [DOI: 10.1177/1087057111401392] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Measuring myotube thickness is a physiological and unbiased approach for screening therapeutic compounds that prevent skeletal muscle atrophy or induce hypertrophy. However, an accurate cell thickness estimate is often quite challenging because of the extreme heterogeneity of the myotube cellular population and therefore the lack of a regular distribution of perturbed myotubes. Here the authors present a novel method to evaluate changes in myotube thickness via measuring cellular electrical impedance. They demonstrate that both qualitative and quantitative changes in electrical impedance as a function of cellular adhesion in real time correlate well with variation in myotube thickness caused by atrophy or hypertrophy agents. Conversely, pharmacologically blocking myotube hypertrophy prevents changes in electrical impedance. Thus, impedance can be used as a reliable and sensitive biomarker for myotube atrophy or hypertrophy. Application of this technique to drug screening might be beneficial in finding novel treatments preventing muscle atrophy and other diseases associated with any morphological change in cell shape.
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Affiliation(s)
- Sergey Rakhilin
- Novartis Institute for Biomedical Research, Cambridge, MA, USA
| | - Gordon Turner
- Novartis Institute for Biomedical Research, Cambridge, MA, USA
| | - Mark Katz
- Novartis Institute for Biomedical Research, Cambridge, MA, USA
| | - Robert Warden
- University of Pennsylvania, Bioengineering Department, Philadelphia, PA, USA
| | | | | | - David J. Glass
- Novartis Institute for Biomedical Research, Cambridge, MA, USA
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129
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Oh EH, Song HS, Park TH. Recent advances in electronic and bioelectronic noses and their biomedical applications. Enzyme Microb Technol 2011; 48:427-37. [PMID: 22113013 DOI: 10.1016/j.enzmictec.2011.04.003] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 04/01/2011] [Indexed: 01/28/2023]
Abstract
Significant effort has been made in the development of an artificial nose system for various applications. Advances in sensor technology have facilitated the development of high-performance electronic and bioelectronic noses. Numerous articles describe the advantages of artificial nose systems for biomedical applications. Recent advances in the development of electronic and bioelectronic noses and their biomedical applications are reviewed in this article.
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Affiliation(s)
- Eun Hae Oh
- Interdisciplinary Program of Bioengineering, Seoul National University, Seoul, Republic of Korea
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130
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Real-time monitoring of flavivirus induced cytopathogenesis using cell electric impedance technology. J Virol Methods 2011; 173:251-8. [PMID: 21349291 DOI: 10.1016/j.jviromet.2011.02.013] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2010] [Revised: 02/11/2011] [Accepted: 02/15/2011] [Indexed: 11/23/2022]
Abstract
A real-time cell analysis (RTCA) system based on cell-substrate electric impedance technology was used to monitor cytopathic effects (CPE) in Vero cell cultures infected with West Nile virus (WNV) and St. Louis encephalitis virus (SLEV) at infectious doses ranging from 10(1) to 10(6) plaque forming units (PFU) of virus. A kinetic parameter characterizing virus-induced CPE, CIT(50) or the time to 50% decrease in cell impedance, was inversely proportional to virus infectious dose. In WNV-infected cells, the onset and rate of CPE was earlier and faster than in SLEV-infected cells, which was consistent with viral cytolytic activity. A mathematical model simulating impedance-based CPE kinetic curves indicated that the replication rate of WNV was about 3 times faster than SLEV. The RTCA system also was used for quantifying the level of cell protection by specific neutralizing antibodies against WNV and SLEV. The onset of WNV or SLEV-induced CPE was delayed in the presence of specific anti-sera, and this delay in the CIT(50) was well correlated with the titer of the neutralizing antibody as measured independently by plaque reduction neutralization tests (PRNT). The RTCA system provided a high throughput and quantitative method for real-time monitoring viral growth in cell culture and its inhibition by neutralizing antibodies.
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131
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Sin YY, Edwards HV, Li X, Day JP, Christian F, Dunlop AJ, Adams DR, Zaccolo M, Houslay MD, Baillie GS. Disruption of the cyclic AMP phosphodiesterase-4 (PDE4)-HSP20 complex attenuates the β-agonist induced hypertrophic response in cardiac myocytes. J Mol Cell Cardiol 2011; 50:872-83. [PMID: 21334344 DOI: 10.1016/j.yjmcc.2011.02.006] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Revised: 02/10/2011] [Accepted: 02/10/2011] [Indexed: 01/06/2023]
Abstract
The small heat shock protein HSP20 is known to be cardioprotective during times of stress and the mechanism underlying its protective abilities depends on its phosphorylation on Ser16 by PKA (protein kinase A). Although the external stimuli that trigger Ser16 phosphorylation have been well studied, the events that modulate spatial and temporal control of this modification remain to be clarified. Here, we report that inhibition of cAMP phosphodiesterase-4 (PDE4) induces the phosphorylation of HSP20 in resting cardiac myocytes and augments its phosphorylation by PKA following β-adrenergic stimulation. Moreover, using peptide array technology, in vitro binding studies, co-immunoprecipitation techniques and immunocytochemistry, we show that HSP20 binds directly to PDE4 within a region of the conserved catalytic domain. We also show that FRET-based, genetically-encoded cAMP reporters anchored to HSP20 exhibit a larger response to PDE4 inhibition compared to free cytosolic cAMP reporters, suggesting that the interaction with PDE4 is crucial in modulating the highly localised pool of cAMP to which HSP20 is exposed. Using information gleaned from peptide array analyses, we developed a cell-permeable peptide that serves to inhibit the interaction of PDE4 with HSP20. Disruption of the HSP20-PDE4 complex, using this peptide, suffices to induce phosphorylation of HSP20 by PKA and to protect against the hypertrophic response measured in neonatal cardiac myocytes following chronic β-adrenergic stimulation.
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Affiliation(s)
- Y Y Sin
- Molecular Pharmacology Group, Wolfson Link and Davidson Buildings, Institute for Psychology and Neurosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, UK
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132
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Irelan JT, Wu MJ, Morgan J, Ke N, Xi B, Wang X, Xu X, Abassi YA. Rapid and quantitative assessment of cell quality, identity, and functionality for cell-based assays using real-time cellular analysis. ACTA ACUST UNITED AC 2011; 16:313-22. [PMID: 21310850 DOI: 10.1177/1087057110397359] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Strict quality control of cells is required for the standardization and interpretation of results in all areas of cell-based research, especially in drug discovery. Real-time cellular analysis using electrical impedance as a readout offers a rapid and highly reproducible method for quality control as it provides a quantitative measure of overall cell morphology and growth. In a case study, the authors demonstrate that samples of a single cell line obtained from several different labs show clear differences in their impedance profiles when compared with the corresponding standard cell line. A number of kinetic parameters were derived from the impedance profiles and used to quantify the differences among these cell lines. Our findings indicate that this methodology can detect cell line differences including mix-ups or contaminations, genetic alterations, and potential epigenetic changes occurring during passaging, all of which can occur in the time scale of a screening campaign. Finally, we provide evidence that these impedance profile differences can be predictive of different outcomes in cell-based functional assays for the effects of small molecules on otherwise seemingly identical cell lines.
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133
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Beltramo M, Brusa R, Mancini I, Scandroglio P. Detecting constitutive activity and protean agonism at cannabinoid-2 receptor. Methods Enzymol 2011; 484:31-51. [PMID: 21036225 DOI: 10.1016/b978-0-12-381298-8.00002-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
Since the cannabinoid system is involved in regulating several physiological functions such as locomotor activity, cognition, nociception, food intake, and inflammatory reaction, it has been the subject of intense study. Research on the pharmacology of this system has enormously progressed in the last 20years. One intriguing aspect that emerged from this research is that cannabinoid receptors (CBs) express a high level of constitutive activity. Investigation on this particular aspect of receptor pharmacology has largely focused on CB1, the CB subtype highly expressed in several brain regions. More recently, research on constitutive activity on the other CB subtype, CB2, was stimulated by the increasing interest on its potential as target for the treatment of various pathologies (e.g., pain and inflammation). There are several possible implications of constitutive activity on the therapeutic action of both agonists and antagonists, and consequently, it is important to have valuable methods to study this aspect of CB2 pharmacology. In the present chapter, we describe three methods to study constitutive activity at CB2: two classical methods relying on the detection of changes in cAMP level and GTPγS binding and a new one based on cell impedance measurement. In addition, we also included a section on detection of protean agonism, which is an interesting pharmacological phenomenon strictly linked to constitutive activity.
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Denelavas A, Weibel F, Prummer M, Imbach A, Clerc RG, Apfel CM, Hertel C. Real-time cellular impedance measurements detect Ca(2+) channel-dependent oscillations of morphology in human H295R adrenoma cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:754-62. [PMID: 21262275 DOI: 10.1016/j.bbamcr.2011.01.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 12/07/2010] [Accepted: 01/13/2011] [Indexed: 01/15/2023]
Abstract
Endocrine cells, such as H295R have been widely used to study secretion of steroid and other hormones. Exocytosis-dependent hormone release is accompanied by an increase in plasma membrane surface area and a decrease in vesicle content. Recovery of vesicles and decrease in plasma membrane area is achieved by endocytotic processes. These changes in the extent of the surface area lead to morphological changes which can be determined by label-free real-time impedance measurements. Exo- and endocytosis have been described to be triggered by activation of L-type Ca(2+) channels. The present study demonstrates that activation of L-type calcium channels induces prolonged oscillating changes in cellular impedance. The data support the hypothesis that a tight regulation of the intracellular Ca(2+) concentration is a prerequisite for the observed cellular impedance oscillations. Furthermore evidence is presented for a mechanism in which the oscillations depend on a Ca(2+)-triggered calmodulin-dependent cascade involving myosin light chain kinase, nonmuscle myosin II and ultimately actin polymerization, a known determinant for cell shape changes and exocytosis in secretory cells. The described assay provides a method to determine continuously prolonged changes in cellular morphology such as exo/endocytosis cycles. This article is part of a Special Issue entitled: 11th European Symposium on Calcium.
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Affiliation(s)
- Athanasios Denelavas
- Metabolic Diseases, F. Hoffmann-La Roche Ltd., Pharma Research and Early Development, Basel, Switzerland
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135
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Ding L, Ju H. Biofunctionalization of nanoparticles for cytosensing and cell surface carbohydrate assay. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c1jm13700j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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136
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Abstract
Label-free biosensors offer integrated, kinetic and multi-parametric measures of receptor biology and ligand pharmacology in whole cells. Being highly sensitive and pathway-unbiased, label-free receptor assays can be used to probe the systems cell biology including pleiotropic signaling of receptors, and to characterize the functional selectivity and phenotypic pharmacology of ligand molecules. These assays provide a new dimension for elucidating receptor biology and for facilitating drug discovery.
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Affiliation(s)
- Ye Fang
- Biochemical Technologies, Science and Technology Division, Corning Inc., Sullivan Park, Corning, NY 14831, Tele: 607-9747203, Fax: 919-9745957
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137
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Monitoring of Cellular Dynamics with Electrochemical Detection Techniques. MODERN ASPECTS OF ELECTROCHEMISTRY 2011. [DOI: 10.1007/978-1-4614-0347-0_1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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138
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Abstract
Label-free biosensors for studying cell biology have finally come of age. Recent developments have advanced the biosensors from low throughput and high maintenance research tools to high throughput and low maintenance screening platforms. In parallel, the biosensors have evolved from an analytical tool solely for molecular interaction analysis to powerful platforms for studying cell biology at the whole cell level. This paper presents historical development, detection principles, and applications in cell biology of label-free biosensors. Future perspectives are also discussed.
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Affiliation(s)
- Ye Fang
- Biochemical Technologies, Science and Technology Division, Corning Inc., Corning, NY 14831, USA
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139
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β-Arrestin 1 inhibits the GTPase-activating protein function of ARHGAP21, promoting activation of RhoA following angiotensin II type 1A receptor stimulation. Mol Cell Biol 2010; 31:1066-75. [PMID: 21173159 DOI: 10.1128/mcb.00883-10] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Activation of the small GTPase RhoA following angiotensin II stimulation is known to result in actin reorganization and stress fiber formation. Full activation of RhoA, by angiotensin II, depends on the scaffolding protein β-arrestin 1, although the mechanism behind its involvement remains elusive. Here we uncover a novel partner and function for β-arrestin 1, namely, in binding to ARHGAP21 (also known as ARHGAP10), a known effector of RhoA activity, whose GTPase-activating protein (GAP) function it inhibits. Using yeast two-hybrid screening, a peptide array, in vitro binding studies, truncation analyses, and coimmunoprecipitation techniques, we show that β-arrestin 1 binds directly to ARHGAP21 in a region that transects the RhoA effector GAP domain. Moreover, we show that the level of a complex containing β-arrestin 1 and ARHGAP21 is dynamically increased following angiotensin stimulation and that the kinetics of this interaction modulates the temporal activation of RhoA. Using information gleaned from a peptide array, we developed a cell-permeant peptide that serves to inhibit the interaction of these proteins. Using this peptide, we demonstrate that disruption of the β-arrestin 1/ARHGAP21 complex results in a more active ARHGAP21, leading to less-efficient signaling via the angiotensin II type 1A receptor and, thereby, attenuation of stimulated stress fiber formation.
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140
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Label-free screening assays: a strategy for finding better drug candidates. Future Med Chem 2010; 2:1703-16. [DOI: 10.4155/fmc.10.246] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The last 10 years have seen advances in automation and high-throughput biochemistry in the drug-discovery arena. However, these advances have not led to improvements in drug-discovery success. Drug programs must find new ways to identify superior compounds. Advances in label-free assay technologies may provide advantages needed for improved drug discovery. In this article, we will discuss high-throughput MS, a technology that allows screening with native substrates and with targets inaccessible to standard assay formats. We will then discuss cell-based label-free biosensors, focusing on the increased information content available when using these platforms. We will conclude with speculation on the future and ways to obtain relevant biological information early in development to ensure the best compounds are promoted to medicinal chemistry campaigns.
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141
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Ona T, Shibata J. Advanced dynamic monitoring of cellular status using label-free and non-invasive cell-based sensing technology for the prediction of anticancer drug efficacy. Anal Bioanal Chem 2010; 398:2505-33. [DOI: 10.1007/s00216-010-4223-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Revised: 08/24/2010] [Accepted: 09/13/2010] [Indexed: 12/26/2022]
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142
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Witkowski PT, Schuenadel L, Wiethaus J, Bourquain DR, Kurth A, Nitsche A. Cellular impedance measurement as a new tool for poxvirus titration, antibody neutralization testing and evaluation of antiviral substances. Biochem Biophys Res Commun 2010; 401:37-41. [PMID: 20828538 DOI: 10.1016/j.bbrc.2010.09.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 09/02/2010] [Indexed: 10/19/2022]
Abstract
Impedance-based biosensing known as real-time cell electronic sensing (RT-CES) belongs to an emerging technology for analyzing the status of cells in vitro. In the present study protocols were developed for an RT-CES-based system (xCELLigence™, Roche Applied Science, ACEA Biosciences Inc.) to supplement conventional techniques in pox virology. First, proliferation of cells susceptible to orthopoxviruses was monitored. For virus titration cells were infected with vaccinia virus and cell status, represented by the dimensionless impedance-based cell index (CI), was monitored. A virus-dose dependent decrease in electrical impedance could be shown. Calculation of calibration curves at a suitable CI covering a dynamic range of 4 log enabled the quantification of virus titers in unknown samples. Similarly, antiviral effects could be determined as shown for anti-poxviral agents ST-246 and Cidofovir. Published values for the in vitro concentration that inhibited virus replication by 50% (IC₅₀) could be confirmed while cytotoxicity in effective concentrations was excluded in long-term incubation experiments. Finally, an RT-CES-based virus neutralization test was established. Various poxvirus-specific antibodies were examined for their neutralizing activity and a calculation mode for the neutralizing antibody titer was introduced. In summary, the presented RT-CES-based methods outmatch end-point assays by observing the cell population throughout the entire experiment while workload and time to result are reduced.
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Affiliation(s)
- Peter T Witkowski
- Robert Koch-Institut, Zentrum für Biologische Sicherheit 1, Nordufer 20, 13353 Berlin, Germany
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143
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Scandroglio P, Brusa R, Lozza G, Mancini I, Petrò R, Reggiani A, Beltramo M. Evaluation of cannabinoid receptor 2 and metabotropic glutamate receptor 1 functional responses using a cell impedance-based technology. ACTA ACUST UNITED AC 2010; 15:1238-47. [PMID: 20811068 DOI: 10.1177/1087057110375615] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Recently, new technologies based on biosensors and called label free have been developed. These technologies eliminate the need for using markers and dyes. The authors applied one of these technologies, based on measurement of cell impedance variation, to study the pharmacological profiles of ligands for the cannabinoid receptor 2 (CB2), a Gi-coupled receptor, and for the metabopotropic glutamate receptor 1 (mGluR1), a Gq-coupled receptor. Reference agonists and antagonists/inverse agonists for the 2 receptors were applied to recombinant cell lines and impedance monitored over time. Agonists (JWH133 and CP55940 for CB2; quisqualate, glutamate, 1S-3R-ACPD, and S-3,5-DHPG for mGluR1) triggered a variation of impedance consistent in both potency and efficacy with data obtained using classical assays measuring cAMP or Ca(2+) levels. This effect was not present in the parental nontransfected cell line, confirming specific receptor-mediated response. Application of antagonists (AM630 for CB2; YM298198, SCH1014222, J&J16259685, and CPCCOEt for mGluR1) reduced agonist-induced impedance changes. The only exception was the mGluR1 antagonist BAY367620 that, while active in the Ca(2+) assay, was inactive in the impedance assay. Overall, these results confirm the possibility of using cell impedance-based technology to study the pharmacological profile of ligands acting at G-protein-coupled receptors coupled to different downstream signaling pathways.
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144
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Assessment of Clostridium difficile infections by quantitative detection of tcdB toxin by use of a real-time cell analysis system. J Clin Microbiol 2010; 48:4129-34. [PMID: 20720023 DOI: 10.1128/jcm.01104-10] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
We explored the use of a real-time cell analysis (RTCA) system for the assessment of Clostridium difficile toxins in human stool specimens by monitoring the dynamic responses of the HS27 cells to tcdB toxins. The C. difficile toxin caused cytotoxic effects on the cells, which resulted in a dose-dependent and time-dependent decrease in cell impedance. The RTCA assay possessed an analytical sensitivity of 0.2 ng/ml for C. difficile toxin B with no cross-reactions with other enterotoxins, nontoxigenic C. difficile, or other Clostridum species. Clinical validation was performed on 300 consecutively collected stool specimens from patients with suspected C. difficile infection (CDI). Each stool specimen was tested in parallel by a real-time PCR assay (PCR), a dual glutamate dehydrogenase and toxin A/B enzyme immunoassay (EIA), and the RTCA assay. In comparison to a reference standard in a combination of the three assays, the RTCA had a specificity of 99.6% and a sensitivity of 87.5% (28 of 32), which was higher than the EIA result (P = 0.005) but lower than the PCR result (P = 0.057). In addition, the RTCA assay allowed for quantification of toxin protein concentration in a given specimen. Among RTCA-positive specimens collected prior to treatment with metronidazole and/or vancomycin, a significant correlation between toxin protein concentrations and clinical CDI severities was observed (R(2) = 0.732, P = 0.0004). Toxin concentrations after treatment (0.89 ng/ml) were significantly lower than those prior to the treatment (15.68 ng/ml, Wilcoxon P = 0.01). The study demonstrates that the RTCA assay provides a functional tool for the potential assessment of C. difficile infections.
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145
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Xiao L, Hu Z, Zhang W, Wu C, Yu H, Wang P. Evaluation of doxorubicin toxicity on cardiomyocytes using a dual functional extracellular biochip. Biosens Bioelectron 2010; 26:1493-9. [PMID: 20732805 DOI: 10.1016/j.bios.2010.07.093] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Revised: 07/16/2010] [Accepted: 07/23/2010] [Indexed: 11/20/2022]
Abstract
Nowadays, cardiotoxicity induced by clinical drugs presents a high prevalence and has aroused great attention onto the effective and reliable drug evaluation before clinical treatment. Doxorubicin (Adriamycin), as a type of anthracycline chemotherapy agent for cancer treatment, was restricted in the clinical use because of its cardiotoxicity. In the present work, a dual functional biochip ExCell integrated with microelectrode arrays and interdigitated electrodes was designed to study the electrophysiological function and physical state of cardiomyocytes under the treatment of doxorubicin. Extracellular field potentials and cell-substrate impedance were measured to respectively express these two functions simultaneously in the same culture. The result detected by ExCell presented a portrait of cardiotoxicity induced by doxorubicin. The amplitude of extracellular field potentials decreased to 93%, 82% and 50% at 50 min treatment of doxorubicin with concentrations of 20 μM, 100 μM and 200 μM, respectively. Successively, beating rate decrease, beat-to-beat variation and Ca(2+) flux manifested severe abnormality. The cell-substrate impedance declined continuously in the depressing process of electrophysiological function and cell death was induced in high concentration treatment. All these result indicate that the biochip ExCell has the potential to be a fast-response and subtle tool for high-throughput drug evaluation assays.
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Affiliation(s)
- Lidan Xiao
- Biosensor National Special Lab, Department of Biomedical Engineering, Zhejiang University, Hangzhou 310027, PR China
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146
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Fisher GW, Adler SA, Fuhrman MH, Waggoner AS, Bruchez MP, Jarvik JW. Detection and quantification of beta2AR internalization in living cells using FAP-based biosensor technology. ACTA ACUST UNITED AC 2010; 15:703-9. [PMID: 20488980 DOI: 10.1177/1087057110370892] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Ligand-dependent receptor internalization is a feature of numerous signaling systems. In this article, the authors describe a new kind of live-cell biosensor of receptor internalization that takes advantage of fluorogen-activating protein (FAP) technology. Recombinant genes that express the human beta2 adrenergic receptor (beta2AR) with FAP domains at their extracellular N-termini were transduced into mammalian cells. Exposure of the cells to membrane-impermeant fluorogens led to a strong fluorescent signal from the cell surface. Agonist-dependent translocation of the receptor from the surface to the cell interior was readily observed and quantified by fluorescence microscopy or flow cytometry in a homogeneous format without wash or separation steps. The approach described here is generalizable to other receptors and cell surface proteins and is adaptable to a variety of fluorescence-based high-throughput screening platforms.
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Affiliation(s)
- Gregory W Fisher
- Technology Center for Networks and Pathways, Molecular Biosensor and Imaging Center, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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147
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Stamer WD, Piwnica D, Jolas T, Carling RW, Cornell CL, Fliri H, Martos J, Pettit SN, Wang JW, Woodward DF. Cellular basis for bimatoprost effects on human conventional outflow. Invest Ophthalmol Vis Sci 2010; 51:5176-81. [PMID: 20435598 DOI: 10.1167/iovs.09-4955] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Bimatoprost is a widely used ocular hypotensive agent to treat glaucoma. It lowers intraocular pressure in humans by increasing both pressure-independent (uveoscleral) and pressure-dependent (conventional) aqueous humor outflow. The present study specifically examines bimatoprost effects on the cells that populate human outflow tissues. METHODS The authors tested for prostamide receptor activation in primary cultures of human trabecular meshwork (TM), Schlemm's canal (SC), and ciliary smooth muscle (CSM) cells using cellular dielectric spectroscopy (CDS). RESULTS The authors observed that bimatoprost produced an immediate and concentration-dependent increase in cell monolayer impedance for TM, SC, and CSM cells with EC(50) values of 4.3, 1.2, and 1.7 nM, respectively; corresponding to decreased cell contractility. Notably, in TM, SC, and CSM cells, bimatoprost was approximately equipotent to the selective FP receptor agonists fluprostenol and 17-phenyl PGF(2α). Bimatoprost effects were insensitive to cholera toxin and pertussis toxin but were abolished by phorbol 12-myristate 13-acetate pretreatment, suggesting Gq-involvement in cell signaling. The effects of bimatoprost on TM and SC cells were inhibited by the prostamide receptor antagonist AGN211334, with IC(50) values of 1.2 and 3.3 μM, respectively. Interestingly, AGN211334 behaved as an apparent inverse agonist in CDS assays involving TM cells but as a neutral prostamide antagonist with SC cells. CONCLUSIONS Taken together, results suggest that bimatoprost specifically activates receptors in both cell types of the human conventional outflow pathway to modify intraocular pressure. However, only TM cell monolayers appear to have autocrine, or agonist-independent, receptor signaling that is sensitive to a prostamide receptor antagonist.
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Affiliation(s)
- W Daniel Stamer
- Department of Ophthalmology and Vision Science, The University of Arizona, Tucson, Arizona 85711, USA.
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148
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Kenakin T, Miller LJ. Seven transmembrane receptors as shapeshifting proteins: the impact of allosteric modulation and functional selectivity on new drug discovery. Pharmacol Rev 2010; 62:265-304. [PMID: 20392808 DOI: 10.1124/pr.108.000992] [Citation(s) in RCA: 458] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
It is useful to consider seven transmembrane receptors (7TMRs) as disordered proteins able to allosterically respond to a number of binding partners. Considering 7TMRs as allosteric systems, affinity and efficacy can be thought of in terms of energy flow between a modulator, conduit (the receptor protein), and a number of guests. These guests can be other molecules, receptors, membrane-bound proteins, or signaling proteins in the cytosol. These vectorial flows of energy can yield standard canonical guest allostery (allosteric modification of drug effect), effects along the plane of the cell membrane (receptor oligomerization), or effects directed into the cytosol (differential signaling as functional selectivity). This review discusses these apparently diverse pharmacological effects in terms of molecular dynamics and protein ensemble theory, which tends to unify 7TMR behavior toward cells. Special consideration will be given to functional selectivity (biased agonism and biased antagonism) in terms of mechanism of action and potential therapeutic application. The explosion of technology that has enabled observation of diverse 7TMR behavior has also shown how drugs can have multiple (pluridimensional) efficacies and how this can cause paradoxical drug classification and nomenclatures.
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Affiliation(s)
- Terry Kenakin
- GlaxoSmithKline, 5 Moore Drive, Mailtstop V-287, Research Triangle Park, NC 27709, USA.
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Peters MF, Vaillancourt F, Heroux M, Valiquette M, Scott CW. Comparing Label-Free Biosensors for Pharmacological Screening With Cell-Based Functional Assays. Assay Drug Dev Technol 2010; 8:219-27. [DOI: 10.1089/adt.2009.0232] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Affiliation(s)
- Matthew F. Peters
- Lead Generation Department, AstraZeneca Pharmaceuticals LP, Wilmington, Delaware
| | | | - Madeleine Heroux
- In Vitro Biology & DMPK, AstraZeneca, R&D Montreal, Montreal, Quebec, Canada
| | - Manon Valiquette
- In Vitro Biology & DMPK, AstraZeneca, R&D Montreal, Montreal, Quebec, Canada
| | - Clay W. Scott
- Lead Generation Department, AstraZeneca Pharmaceuticals LP, Wilmington, Delaware
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Compound Collection Enhancement and Paradigms for High-Throughput Screening — an Update. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2010. [DOI: 10.1016/s0065-7743(10)45025-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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