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Borgarelli C, Klingl YE, Escamilla-Ayala A, Munck S, Van Den Bosch L, De Borggraeve WM, Ismalaj E. Lighting Up the Plasma Membrane: Development and Applications of Fluorescent Ligands for Transmembrane Proteins. Chemistry 2021; 27:8605-8641. [PMID: 33733502 DOI: 10.1002/chem.202100296] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Indexed: 12/16/2022]
Abstract
Despite the fact that transmembrane proteins represent the main therapeutic targets for decades, complete and in-depth knowledge about their biochemical and pharmacological profiling is not fully available. In this regard, target-tailored small-molecule fluorescent ligands are a viable approach to fill in the missing pieces of the puzzle. Such tools, coupled with the ability of high-precision optical techniques to image with an unprecedented resolution at a single-molecule level, helped unraveling many of the conundrums related to plasma proteins' life-cycle and druggability. Herein, we review the recent progress made during the last two decades in fluorescent ligand design and potential applications in fluorescence microscopy of voltage-gated ion channels, ligand-gated ion channels and G-coupled protein receptors.
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Affiliation(s)
- Carlotta Borgarelli
- Department of Chemistry, Molecular Design and Synthesis, KU Leuven Campus Arenberg Celestijnenlaan 200F -, box 2404, 3001, Leuven, Belgium
| | - Yvonne E Klingl
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), KU Leuven Campus Gasthuisberg O&N5 -, box 602 Herestraat 49, 3000, Leuven, Belgium.,Laboratory of Neurobiology, VIB, Center for Brain &, Disease Research, VIB-KU Leuven Campus Gasthuisberg O&N5 -, box 602 Herestraat 49, 3000, Leuven, Belgium
| | - Abril Escamilla-Ayala
- Center for Brain & Disease Research, & VIB BioImaging Core, VIB-KU Leuven Campus Gasthuisberg O&N5 -, box 602 Herestraat 49, 3000, Leuven, Belgium.,Department of Neurosciences, Leuven Brain Institute, KU Leuven, Campus Gasthuisberg O&N5 - box 602 Herestraat 49, 3000, Leuven, Belgium
| | - Sebastian Munck
- Center for Brain & Disease Research, & VIB BioImaging Core, VIB-KU Leuven Campus Gasthuisberg O&N5 -, box 602 Herestraat 49, 3000, Leuven, Belgium.,Department of Neurosciences, Leuven Brain Institute, KU Leuven, Campus Gasthuisberg O&N5 - box 602 Herestraat 49, 3000, Leuven, Belgium
| | - Ludo Van Den Bosch
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), KU Leuven Campus Gasthuisberg O&N5 -, box 602 Herestraat 49, 3000, Leuven, Belgium.,Laboratory of Neurobiology, VIB, Center for Brain &, Disease Research, VIB-KU Leuven Campus Gasthuisberg O&N5 -, box 602 Herestraat 49, 3000, Leuven, Belgium
| | - Wim M De Borggraeve
- Department of Chemistry, Molecular Design and Synthesis, KU Leuven Campus Arenberg Celestijnenlaan 200F -, box 2404, 3001, Leuven, Belgium
| | - Ermal Ismalaj
- Department of Chemistry, Molecular Design and Synthesis, KU Leuven Campus Arenberg Celestijnenlaan 200F -, box 2404, 3001, Leuven, Belgium
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Jakobs D, Hage-Hülsmann A, Prenner L, Kolb C, Weiser D, Häberlein H. Downregulation of β1 -adrenergic receptors in rat C6 glioblastoma cells by hyperforin and hyperoside from St John's wort. ACTA ACUST UNITED AC 2013; 65:907-15. [PMID: 23647684 DOI: 10.1111/jphp.12050] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Accepted: 01/15/2013] [Indexed: 01/22/2023]
Abstract
OBJECTIVES While the use of St John's wort extracts as treatment for mild to moderate depression is well established the mode of action is still under investigation. Individual constituents of St John's wort extract were tested for possible effects on the β1 AR density and a subsequent change in downstream signalling in rat C6 glioblastoma cells. METHODS The effect of compounds from St John's wort extract on the downregulation of β1 -adrenergic receptor-GFP fusion proteins (β1 AR-green fluorescent protein (GFP)) of transfected rat C6 gliobastoma cells (C6-β1 AR-GFP) was investigated by means of confocal laser scanning microscopy (LSM). The influence on the lateral mobility of β1 AR-GFP in C6-β1 AR-GFP was investigated by fluorescence correlation spectroscopy. The formation of second messenger was determined by c-AMP-assay. KEY FINDINGS Confocal LSM revealed that pretreatment of cells with 1 μm of hyperforin and hyperoside for 6 days, respectively, led to an internalization of β1 AR-GFP under non-stimulating conditions. Observation by fluorescence correlation spectroscopy showed two diffusion time constants for control cells, with τdiff1 = 0.78 ± 0.18 ms and τdiff2 = 122.53 ± 69.41 ms, similarly distributed. Pretreatment with 1 μm hyperforin or 1 μm hyperoside for 3 days did not alter the τdiff values but decreased the fraction of τdiff1 whereas the fraction of τdiff2 increased significantly. An elevated level of β1 AR-GFP with hindered lateral mobility was in line with β1 AR-GFP internalization induced by hyperforin and hyperoside, respectively. A reduced β1 -adrenergic responsiveness was assumed for C6 gliobastoma cells after pretreatment for 6 days with 1 μm of both hyperforin and hyperoside, which was confirmed by decreased cAMP formation of about 10% and 5% under non-stimulating conditions. Decrease in cAMP formation by 23% for hyperforin and 15% for hyperoside was more pronounced after stimulation with 10 μm dobutamine for 30 min. CONCLUSIONS The treatment of C6 gliobastoma cells with hyperforin and hyperoside results in a reduced β1 AR density in the plasma membrane and a subsequent reduced downstream signalling.
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Affiliation(s)
- Daniel Jakobs
- Institute of Biochemistry and Molecular Biology, Rheinische Friedrich-Wilhelm University, Bonn, Germany
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Caballero-George C, Sorkalla T, Jakobs D, Bolaños J, Raja H, Shearer C, Bermingham E, Häberlein H. Fluorescence correlation spectroscopy in drug discovery: study of Alexa532-endothelin 1 binding to the endothelin ETA receptor to describe the pharmacological profile of natural products. ScientificWorldJournal 2012; 2012:524169. [PMID: 22623909 PMCID: PMC3353486 DOI: 10.1100/2012/524169] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 12/12/2011] [Indexed: 11/17/2022] Open
Abstract
Fluorescence correlation spectroscopy and the newly synthesized Alexa532-ET1 were used to study the dynamics of the endothelin ETA receptor-ligand complex alone and under the influence of a semisynthetic selective antagonist and a fungal extract on living A10 cells. Dose-dependent increase of inositol phosphate production was seen for Alexa532-ET1, and its binding was reduced to 8% by the selective endothelin ETA antagonist BQ-123, confirming the specific binding of Alexa532-ET1 to the endothelin ETA receptor. Two different lateral mobilities of the receptor-ligand complexes within the cell membrane were found allowing the discrimination of different states for this complex. BQ-123 showed a strong binding affinity to the “inactive” receptor state characterized by the slow diffusion time constant. A similar effect was observed for the fungal extract, which completely displaced Alexa532-ET1 from its binding to the “inactive” receptor state. These findings suggest that both BQ-123 and the fungal extract act as inverse agonists.
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Affiliation(s)
- Catherina Caballero-George
- Department of Molecular Pharmacology and Pharmacognosy, Drug Discovery Center, Institute for Scientific Research and High Technology Services, Panama City, Panama.
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Chen J, Irudayaraj J. Fluorescence Lifetime Cross Correlation Spectroscopy Resolves EGFR and Antagonist Interaction in Live Cells. Anal Chem 2010; 82:6415-21. [PMID: 20586411 DOI: 10.1021/ac101236t] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jiji Chen
- Birck Nanotechnology & Bindley Bioscience Center, Department of Agricultural & Biological Engineering, Purdue University, West Lafayette, Indiana 47906
| | - Joseph Irudayaraj
- Birck Nanotechnology & Bindley Bioscience Center, Department of Agricultural & Biological Engineering, Purdue University, West Lafayette, Indiana 47906
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Salles JI, Bastos VH, Cunha M, Machado D, Cagy M, Furtado V, Basile LF, Piedade R, Ribeiro P. Efeitos neuromoduladores do bromazepam quando indivíduos são expostos a uma tarefa de aprendizagem motora: eletrencefalografia quantitativa (EEGq). ARQUIVOS DE NEURO-PSIQUIATRIA 2006; 64:112-7. [PMID: 16622565 DOI: 10.1590/s0004-282x2006000100023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Os efeitos sedativos do bromazepam no desempenho cognitivo têm sido amplamente investigados. Várias abordagens têm sido implementadas no intuito de avaliar a influência do bromazepam em sujeitos submetidos à tarefa motora. Neste contexto, o presente estudo objetiva avaliar as alterações eletrofisiológicas em sujeitos expostos à tarefa de datilografia e tratados com bromazepam (6 mg). Os dados do EEGq foram gravados simultaneamente à tarefa. Em particular, a potência relativa na banda delta (0,5-3,5 Hz) foi analizada. O tempo de execução e erros durante a tarefa foram considerados variáveis comportamentais. O grupo experimental (bromazepam 6 mg) demonstrou melhor desempenho e valores de potência relativa mais elevados que o grupo controle (placebo). Estes resultados sugerem que menor nível de ansiedade favorece o desempenho motor.
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Affiliation(s)
- José Inácio Salles
- Laboratório de Mapeamento Cerebral e Integração Sensório-Motora, Instituto de Psiquiatria, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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Machado D, Bastos VH, Cunha M, Furtado V, Cagy M, Piedade R, Ribeiro P. Efeitos do Bromazepam observados pela eletroencefalografia quantitativa (EEGq) durante a prática de datilografia. ARQUIVOS DE NEURO-PSIQUIATRIA 2005; 63:452-8. [PMID: 16059597 DOI: 10.1590/s0004-282x2005000300016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A eficiência com que uma informação é transmitida dentro da circuitaria neural pode ser alterada por neuromoduladores. O uso do Bromazepam nos transtornos de ansiedade se deve a sua propriedade ansiolítica. Porém, os efeitos deste benzodiazepínico na aprendizagem motora não são plenamente conhecidos. O objetivo deste estudo foi analisar alterações neuropsicológicas, comportamentais e eletrofisiológicas decorrentes da administração de Bromazepam (6 mg) durante o aprendizado de uma tarefa motora. A amostra consistiu de 26 sujeitos saudáveis, de ambos os sexos, entre 19 e 36 anos. Os grupos controle (placebo) e experimental (Bromazepam 6 mg) foram submetidos ao aprendizado de datilografia, em desenho duplo-cego randomizado. Os resultados não revelaram diferenças nas variáveis neuropsicológicas e comportamentais entre os grupos. Testes estatísticos demonstraram interação entre condição e momento e um efeito principal para setor, ou seja, uma diminuição da potência relativa no hemisfério direito. Esta diminuição de potência sugere uma especialização da circuitaria neural no hemisfério contralateral ao dedo utilizado no pressionamento da tecla. Tal diminuição é independente do uso da droga.
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Affiliation(s)
- Dionis Machado
- Laboratório de Mapeamento Cerebral e Integração Sensório-Motora, Instituto de Psiquiatria, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil
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Abouzied MM, El-Tahir HM, Prenner L, Häberlein H, Gieselmann V, Franken S. Hepatoma-derived growth factor. Significance of amino acid residues 81-100 in cell surface interaction and proliferative activity. J Biol Chem 2005; 280:10945-54. [PMID: 15655245 DOI: 10.1074/jbc.m414652200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hepatoma-derived growth factor (HDGF) has proliferative, angiogenic, and neurotrophic activity. It plays a putative role in the development and progression of cancer. When expressed in cells, the mitogenic activity of HDGF depends on its nuclear localization, but it also stimulates proliferation when added to the cell culture medium. A cell surface receptor for HDGF has not been identified so far. We investigated the interaction of various purified recombinant HDGF fusion proteins with the cell surface of NIH 3T3 fibroblasts. We showed that binding of a HDGF-beta-galactosidase fusion protein to the cell surface of NIH 3T3 fibroblasts was saturable, occurred with high affinity (K(D) = 14 nm), and had a proliferative effect. We identified a peptide comprising amino acid residues 81-100 within the amino-terminal part of HDGF that bound to the cell surface of NIH 3T3 cells with saturation and affinity values similar to those of HDGF. When added to primary human fibroblasts, this peptide stimulated proliferation. Substitution of a single amino acid (K96A) within this peptide was sufficient to abolish its binding to the cell surface and its proliferative activity. In contrast, when expressed transiently in NIH 3T3 cells, a HDGF-beta-galactosidase fusion protein in which amino acid residues 81-100 were deleted still had proliferative activity, whereas a fusion protein containing only the 81-100 peptide did not. Our results suggest the existence of a plasma membrane-located HDGF receptor for which signaling depends on amino acid residues 81-100 of HDGF. This region differs from the one that has been recently identified to be essential for mitogenic activity depending on the nuclear localization of HDGF. Thus, HDGF exerts its proliferative activity via two different pathways.
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Affiliation(s)
- Mekky M Abouzied
- Institut für Physiologische Chemie, Rheinische Friedrich-Wilhelms Universität, Nussallee 11, 53115 Bonn, Germany
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