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Camacho-Hernandez GA, Jahan K, Newman AH. Illuminating the monoamine transporters: Fluorescently labelled ligands to study dopamine, serotonin and norepinephrine transporters. Basic Clin Pharmacol Toxicol 2023; 133:473-484. [PMID: 36527444 PMCID: PMC11309735 DOI: 10.1111/bcpt.13827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022]
Abstract
Fluorescence microscopy has revolutionized the visualization of physiological processes in live-cell systems. With the recent innovations in super resolution microscopy, these events can be examined with high precision and accuracy. The development of fluorescently labelled small molecules has provided a significant advance in understanding the physiological relevance of targeted proteins that can now be visualized at the cellular level. One set of physiologically important target proteins are the monoamine transporters (MATs) that play an instrumental role in maintaining monoamine signalling homeostasis. Understanding the mechanisms underlying their regulation and dysregulation is fundamental to treating several neuropsychiatric conditions such as attention deficit hyperactivity disorder (ADHD), anxiety, depression and substance use disorders. Herein, we describe the rationale behind the small molecule design of fluorescently labelled ligands (FLL) either as MAT substrates or inhibitors as well as their applications to advance our understanding of this class of transporters in health and disease.
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Affiliation(s)
- Gisela Andrea Camacho-Hernandez
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institutes on Drug Abuse - Intramural Research Program, Baltimore, Maryland, USA
| | - Khorshada Jahan
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institutes on Drug Abuse - Intramural Research Program, Baltimore, Maryland, USA
| | - Amy Hauck Newman
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institutes on Drug Abuse - Intramural Research Program, Baltimore, Maryland, USA
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2
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Török G, Cserép GB, Telek A, Arany D, Váradi M, Homolya L, Kellermayer M, Kele P, Németh K. Large Stokes-shift bioorthogonal probes for STED, 2P-STED and multi-color STED nanoscopy. Methods Appl Fluoresc 2021; 9:015006. [PMID: 33427202 DOI: 10.1088/2050-6120/abb363] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Synthesis and multiple STED imaging applications of four, red-emitting (610-670 nm), tetrazine-functionalized fluorescent probes (CBRD = Chemical Biology Research group Dye 1-4) with large Stokes-shift is presented. Present studies revealed the super-resolution microscopy applicability of the probes as demonstrated through bioorthogonal labeling scheme of cytoskeletal proteins actin and keratin-19, and mitochondrial protein TOMM20. Furthermore, super-resolved images of insulin receptors in live-cell bioorthogonal labeling schemes through a genetically encoded cyclooctynylated non-canonical amino acid are also presented. The large Stokes-shifts and the wide spectral bands of the probes enabled the use of two common depletion lasers (660 nm and 775 nm). The probes were also found suitable for super-resolution microscopy in combination with two-photon excitation (2P-STED) resulting in improved spatial resolution. One of the dyes was also used together with two commercial dyes in the three-color STED imaging of intracellular structures.
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Affiliation(s)
- György Török
- Chemical Biology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar tudósok krt. 2., H-1117 Budapest, Hungary. Department of Biophysics and Radiation Biology, Semmelweis University, Tűzoltó u. 37-47., H-1094 Budapest, Hungary. Laboratory of Molecular Cell Biology, Institute of Enzymology, Research Centre for Natural Sciences, Magyar tudósok krt. 2., H-1117 Budapest, Hungary
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3
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O’Hagan S, Kell DB. Structural Similarities between Some Common Fluorophores Used in Biology, Marketed Drugs, Endogenous Metabolites, and Natural Products. Mar Drugs 2020; 18:E582. [PMID: 33238416 PMCID: PMC7700180 DOI: 10.3390/md18110582] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 11/16/2020] [Accepted: 11/20/2020] [Indexed: 12/12/2022] Open
Abstract
It is known that at least some fluorophores can act as 'surrogate' substrates for solute carriers (SLCs) involved in pharmaceutical drug uptake, and this promiscuity is taken to reflect at least a certain structural similarity. As part of a comprehensive study seeking the 'natural' substrates of 'orphan' transporters that also serve to take up pharmaceutical drugs into cells, we have noted that many drugs bear structural similarities to natural products. A cursory inspection of common fluorophores indicates that they too are surprisingly 'drug-like', and they also enter at least some cells. Some are also known to be substrates of efflux transporters. Consequently, we sought to assess the structural similarity of common fluorophores to marketed drugs, endogenous mammalian metabolites, and natural products. We used a set of some 150 fluorophores along with standard fingerprinting methods and the Tanimoto similarity metric. Results: The great majority of fluorophores tested exhibited significant similarity (Tanimoto similarity > 0.75) to at least one drug, as judged via descriptor properties (especially their aromaticity, for identifiable reasons that we explain), by molecular fingerprints, by visual inspection, and via the "quantitative estimate of drug likeness" technique. It is concluded that this set of fluorophores does overlap with a significant part of both the drug space and natural products space. Consequently, fluorophores do indeed offer a much wider opportunity than had possibly been realised to be used as surrogate uptake molecules in the competitive or trans-stimulation assay of membrane transporter activities.
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Affiliation(s)
- Steve O’Hagan
- Department of Chemistry, The University of Manchester, Manchester M13 9PT, UK;
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess St, Manchester M1 7DN, UK
| | - Douglas B. Kell
- Department of Biochemistry and Systems Biology, Institute of Molecular, Integrative and Systems Biology, Biosciences Building, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK
- Novo Nordisk Foundation Centre for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, 2800 Kongens Lyngby, Denmark
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4
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Cao LL, Holmes AP, Marshall JM, Fabritz L, Brain KL. Dynamic monitoring of single-terminal norepinephrine transporter rate in the rodent cardiovascular system: A novel fluorescence imaging method. Auton Neurosci 2020; 223:102611. [PMID: 31901784 PMCID: PMC6977090 DOI: 10.1016/j.autneu.2019.102611] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/29/2019] [Accepted: 12/14/2019] [Indexed: 12/17/2022]
Abstract
Here, we validate the use of a novel fluorescent norepinephrine transporter (NET) substrate for dynamic measurements of transporter function in rodent cardiovascular tissue; this technique avoids the use of radiotracers and provides single-terminal resolution. Rodent (Wistar rats and C57BL/6 mice) hearts and mesenteric arteries (MA) were isolated, loaded with NET substrate Neurotransmitter Transporter Uptake Assay (NTUA) ex vivo and imaged with confocal microscopy. NTUA labelled noradrenergic nerve terminals in all four chambers of the heart and on the surface of MA. In all tissues, a temperature-dependent, stable linear increase in intra-terminal fluorescence upon NTUA exposure was observed; this was abolished by NET inhibitor desipramine (1 μM) and reversed by indirectly-acting sympathomimetic amine tyramine (10 μM). NET reuptake rates were similar across the mouse cardiac chambers. In both species, cardiac NET activity was significantly greater than in MA (by 62 ± 29% (mouse) and 21 ± 16% (rat)). We also show that mouse NET reuptake rate was twice as fast as that in the rat (for example, in the heart, by 94 ± 30%). Finally, NET reuptake rate in the mouse heart was attenuated with muscarinic agonist carbachol (10 μM) thus demonstrating the potential for parasympathetic regulation of norepinephrine clearance. Our data provide the first demonstration of monitoring intra-terminal NET function in rodent cardiovascular tissue. This straightforward method allows dynamic measurements of transporter rate in response to varying physiological conditions and drug treatments; this offers the potential to study new mechanisms of sympathetic dysfunction associated with cardiovascular disease.
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Affiliation(s)
- Lily L Cao
- School of Biomedical Science, Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, B15 2TT, United Kingdom.
| | - Andrew P Holmes
- School of Biomedical Science, Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, B15 2TT, United Kingdom.
| | - Janice M Marshall
- School of Biomedical Science, Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, B15 2TT, United Kingdom.
| | - Larissa Fabritz
- Institute of Cardiovascular Science, College of Medical and Dental Sciences, University of Birmingham, B15 2TT, United Kingdom; Department of Cardiology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom.
| | - Keith L Brain
- School of Biomedical Science, Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, B15 2TT, United Kingdom.
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Imaging mitochondria and plasma membrane in live cells using solvatochromic styrylpyridines. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2019; 203:111732. [PMID: 31864089 DOI: 10.1016/j.jphotobiol.2019.111732] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/20/2019] [Accepted: 12/04/2019] [Indexed: 12/16/2022]
Abstract
Investigating the dynamics of different biomolecules in the cellular milieu through microscopic imaging has gained paramount importance in the last decade. Continuous developments in the field of microscopy are paralleled by the design and synthesis of fluorophores that target specific compartments within a cell. In this study, we have synthesized four fluorescent styrene derivatives, a neutral styrylpridine, three cationic styrylpyridinium probes with and without cholesterol tether, and investigated their absorption, emission, and cellular imaging properties. The fluorophores show solvatochromic emission attributed to intramolecular charge transfer from donor to acceptor with an emission range of 500-600 nm. The fluorescent cholesterol conjugate labels plasma membrane effectively while the fluorophores devoid of the cholesterol tether label mitochondria. Cholesterol conjugate also shows strong interaction with liposome membrane. Furthermore, the fluorophores alsotrack the mitochondria in live cells with high specificity. Cell viability assay showed overall non-toxic nature of the probes even at higher fluorophore concentrations. Through sidearm modifications, keeping the fluorescent core intact, we successfully targeted specific subcellular compartments of neuronal (N2a) and non-neuronal (HeLa) mammalian cell lines. This strategy of using a single molecular scaffold with subtle substitutions could be ideal in generating a variety of fluorophores targeting other subcellular compartments.
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Tang Y, Liu H, Zhang H, Li D, Su J, Zhang S, Zhou H, Li S, Wu J, Tian Y. A series of stilbazolium salts with A-π-A model and their third-order nonlinear optical response in the near-IR region. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017; 175:92-99. [PMID: 28024252 DOI: 10.1016/j.saa.2016.12.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Revised: 12/06/2016] [Accepted: 12/13/2016] [Indexed: 06/06/2023]
Abstract
A series of water-soluble stilbazolium salts with A-π-A (A: Acceptor) model have been synthesized and fully characterized. The results obtained from absorption spectra and TD-DFT computational studies show that there is a relative strong intramolecular charge transfer (ICT) transition from pyridine unit to pyridine cation of the stilbazolium salts. Furthermore, it is found that the three stilbazolium salts (T1, T2, T3) show the strong two-photon absorption (2PA) response in the near-infrared (IR) region by Z-scan technique using femtosecond laser. And the stilbazolium salt T3 shows the largest two-photon absorption cross-section and third-order nonlinear optical (NLO) coefficient χ(3) at 730nm, indicating the different terminal substituent group of the pyridinium plays a vital role in third-order NLO behavior.
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Affiliation(s)
- Yiwen Tang
- Department of Chemistry, Key Laboratory of Functional Inorganic Material Chemistry of Anhui Province, Anhui University, Hefei 230039, PR China
| | - Hui Liu
- Department of Chemistry, Key Laboratory of Functional Inorganic Material Chemistry of Anhui Province, Anhui University, Hefei 230039, PR China
| | - Hui Zhang
- Department of Chemistry, Key Laboratory of Functional Inorganic Material Chemistry of Anhui Province, Anhui University, Hefei 230039, PR China
| | - Dandan Li
- Department of Chemistry, Key Laboratory of Functional Inorganic Material Chemistry of Anhui Province, Anhui University, Hefei 230039, PR China
| | - Jian Su
- Department of Chemistry, Key Laboratory of Functional Inorganic Material Chemistry of Anhui Province, Anhui University, Hefei 230039, PR China
| | - Shengyi Zhang
- Department of Chemistry, Key Laboratory of Functional Inorganic Material Chemistry of Anhui Province, Anhui University, Hefei 230039, PR China
| | - Hongping Zhou
- Department of Chemistry, Key Laboratory of Functional Inorganic Material Chemistry of Anhui Province, Anhui University, Hefei 230039, PR China
| | - Shengli Li
- Department of Chemistry, Key Laboratory of Functional Inorganic Material Chemistry of Anhui Province, Anhui University, Hefei 230039, PR China
| | - Jieying Wu
- Department of Chemistry, Key Laboratory of Functional Inorganic Material Chemistry of Anhui Province, Anhui University, Hefei 230039, PR China.
| | - Yupeng Tian
- Department of Chemistry, Key Laboratory of Functional Inorganic Material Chemistry of Anhui Province, Anhui University, Hefei 230039, PR China.
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7
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Wilson JN, Liu W, Brown AS, Landgraf R. Binding-induced, turn-on fluorescence of the EGFR/ERBB kinase inhibitor, lapatinib. Org Biomol Chem 2015; 13:5006-11. [PMID: 25820099 DOI: 10.1039/c5ob00239g] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
We report the photophysical properties, binding-induced turn-on emission, and fluorescence imaging of the cellular uptake and distribution of lapatinib, an EGFR/ERBB inhibitor. Lapatinib, a type II, i.e. inactive state, inhibitor that targets the ATP binding pocket of the EGFR family of receptor tyrosine kinases. DFT calculations predict that the 6-furanylquinazoline core of lapatinib should exhibit an excited state with charge transfer character and an S0 to S1 transition energy of 3.4 eV. Absorption confirms an optical transition in the near UV to violet, while fluorescence spectroscopy shows that photoemission is highly sensitive to solvent polarity. The hydrophobicity of lapatinib leads to fluorescent aggregates in solution, however, binding to the lipid-carrier protein, BSA or to the kinase domain of ERBB2, produces spectroscopically distinct photoemission. Confocal fluorescence microscopy imaging of lapatinib uptake in ERBB2-overexpressing MCF7 and BT474 cells reveals pools of intracellular inhibitor with emission profiles consistent with aggregated lapatinib.
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Affiliation(s)
- James N Wilson
- Department of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33124, USA.
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Ayala-Lopez N, Jackson WF, Burnett R, Wilson JN, Thompson JM, Watts SW. Organic cation transporter 3 contributes to norepinephrine uptake into perivascular adipose tissue. Am J Physiol Heart Circ Physiol 2015; 309:H1904-14. [PMID: 26432838 PMCID: PMC4698381 DOI: 10.1152/ajpheart.00308.2015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 09/30/2015] [Indexed: 12/23/2022]
Abstract
Perivascular adipose tissue (PVAT) reduces vasoconstriction to norepinephrine (NE). A mechanism by which PVAT could function to reduce vascular contraction is by decreasing the amount of NE to which the vessel is exposed. PVATs from male Sprague-Dawley rats were used to test the hypothesis that PVAT has a NE uptake mechanism. NE was detected by HPLC in mesenteric PVAT and isolated adipocytes. Uptake of NE (10 μM) in mesenteric PVAT was reduced by the NE transporter (NET) inhibitor nisoxetine (1 μM, 73.68 ± 7.62%, all values reported as percentages of vehicle), the 5-hydroxytryptamine transporter (SERT) inhibitor citalopram (100 nM) with the organic cation transporter 3 (OCT3) inhibitor corticosterone (100 μM, 56.18 ± 5.21%), and the NET inhibitor desipramine (10 μM) with corticosterone (100 μM, 61.18 ± 6.82%). Aortic PVAT NE uptake was reduced by corticosterone (100 μM, 53.01 ± 10.96%). Confocal imaging of mesenteric PVAT stained with 4-[4-(dimethylamino)-styrl]-N-methylpyridinium iodide (ASP(+)), a fluorescent substrate of cationic transporters, detected ASP(+) uptake into adipocytes. ASP(+) (2 μM) uptake was reduced by citalopram (100 nM, 66.68 ± 6.43%), corticosterone (100 μM, 43.49 ± 10.17%), nisoxetine (100 nM, 84.12 ± 4.24%), citalopram with corticosterone (100 nM and 100 μM, respectively, 35.75 ± 4.21%), and desipramine with corticosterone (10 and 100 μM, respectively, 50.47 ± 5.78%). NET protein was not detected in mesenteric PVAT adipocytes. Expression of Slc22a3 (OCT3 gene) mRNA and protein in PVAT adipocytes was detected by RT-PCR and immunocytochemistry, respectively. These end points support the presence of a transporter-mediated NE uptake system within PVAT with a potential mediator being OCT3.
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Affiliation(s)
- Nadia Ayala-Lopez
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - Robert Burnett
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - James N Wilson
- Department of Chemistry, University of Miami, Coral Gables, Florida
| | - Janice M Thompson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - Stephanie W Watts
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
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9
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Pitter DRG, Brown AS, Baker JD, Wilson JN. One probe, two-channel imaging of nuclear and cytosolic compartments with orange and red emissive dyes. Org Biomol Chem 2015; 13:9477-84. [PMID: 26257246 DOI: 10.1039/c5ob01428j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Several new DNA-targeting probes that exhibit binding-induced 'turn on' fluorescence are presented. Two of the dyes, orange emissive 1, (E)-4-(4(-4-methylpiperazin-1-yl)phenyl)6-(4-(4-methylpi-perazin-1-yl)styryl)pyrimidin-2-ol), and red emissive 2, (E)-4-(4(-4-methyl-piperazin-1-yl)-phenyl)6-(4-(4-methylpiperazin-1-yl)styryl)-1,3-propanedionato-κO,κO']difluoroborane), are brightly fluorescent when bound to DNA, but are virtually non-fluorescent in aqueous solutions. Confocal fluorescence microscopy of live BT474, MCF7 and HEK293 cells demonstrates that both probes are cell permeable and rapidly accumulated intracellularly into cell nuclei and the cytosol. Taking advantage of their environmental sensitivity, these two pools of fluorophores are readily resolved into separate channels, and thus, a single dye allows two-color imaging of the nuclear and cytosolic compartments.
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Affiliation(s)
- Demar R G Pitter
- Department of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, FL 33146, USA.
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Agnihotri H, Vasu AK, Palakollu V, Kanvah S. Neutral and cationic pyridylbutadienes: solvatochromism and fluorescence response with sodium cholate. Photochem Photobiol Sci 2015; 14:2159-67. [DOI: 10.1039/c5pp00179j] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Characteristic ICT emission in solvents and enhanced emission intensity in presence of sodium cholate.
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Affiliation(s)
- Harsha Agnihotri
- Department of Chemistry
- Indian Institute of Technology Gandhinagar
- Ahmedabad 382 424
- India
| | - Anuji K. Vasu
- Department of Chemistry
- Indian Institute of Technology Gandhinagar
- Ahmedabad 382 424
- India
| | | | - Sriram Kanvah
- Department of Chemistry
- Indian Institute of Technology Gandhinagar
- Ahmedabad 382 424
- India
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Bojtár M, Szakács Z, Hessz D, Kubinyi M, Bitter I. Optical spectroscopic studies on the complexation of stilbazolium dyes with a water soluble pillar[5]arene. RSC Adv 2015. [DOI: 10.1039/c4ra14809f] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The host–guest interactions of carboxylato-pillar[5]arene (WPA5) and three stilbazolium dyes were studied by optical spectroscopy. A fluorescence indicator displacement based on WPA5 was shown to detect paraquat in aqueous solution.
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Affiliation(s)
- Márton Bojtár
- Department of Organic Chemistry and Technology
- Budapest University of Technology and Economics
- 1521 Budapest
- Hungary
| | - Zoltán Szakács
- Department of Physical Chemistry and Materials Science
- Budapest University of Technology and Economics
- 1521 Budapest
- Hungary
| | - Dóra Hessz
- Institute of Materials and Environmental Chemistry
- Research Centre for Natural Sciences
- Hungarian Academy of Sciences
- 1519 Budapest
- Hungary
| | - Miklós Kubinyi
- Department of Physical Chemistry and Materials Science
- Budapest University of Technology and Economics
- 1521 Budapest
- Hungary
- Institute of Materials and Environmental Chemistry
| | - István Bitter
- Department of Organic Chemistry and Technology
- Budapest University of Technology and Economics
- 1521 Budapest
- Hungary
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12
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Wilson JN, Ladefoged LK, Babinchak WM, Schiøtt B. Binding-induced fluorescence of serotonin transporter ligands: A spectroscopic and structural study of 4-(4-(dimethylamino)phenyl)-1-methylpyridinium (APP(+)) and APP(+) analogues. ACS Chem Neurosci 2014; 5:296-304. [PMID: 24460204 DOI: 10.1021/cn400230x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The binding-induced fluorescence of 4-(4-(dimethylamino)-phenyl)-1-methylpyridinium (APP(+)) and two new serotonin transporter (SERT)-binding fluorescent analogues, 1-butyl-4-[4-(1-dimethylamino)phenyl]-pyridinium bromide (BPP(+)) and 1-methyl-4-[4-(1-piperidinyl)phenyl]-pyridinium (PPP(+)), has been investigated. Optical spectroscopy reveals that these probes are highly sensitive to their chemical microenvironment, responding to variations in polarity with changes in transition energies and responding to changes in viscosity or rotational freedom with emission enhancements. Molecular docking calculations reveal that the probes are able to access the nonpolar and conformationally restrictive binding pocket of SERT. As a result, the probes exhibit previously not identified binding-induced turn-on emission that is spectroscopically distinct from dyes that have accumulated intracellularly. Thus, binding and transport dynamics of SERT ligands can be resolved both spatially and spectroscopically.
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Affiliation(s)
- James N. Wilson
- Department of Chemistry, University of Miami, Coral Gables, Florida 33124, United States
| | - Lucy Kate Ladefoged
- inSPIN
and iNANO Centers, Department of Chemistry, Aarhus University, 8000 Aarhus C, Denmark
| | - W. Michael Babinchak
- Department of Chemistry, University of Miami, Coral Gables, Florida 33124, United States
| | - Birgit Schiøtt
- inSPIN
and iNANO Centers, Department of Chemistry, Aarhus University, 8000 Aarhus C, Denmark
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Pitter DRG, Wigenius J, Brown AS, Baker JD, Westerlund F, Wilson JN. Turn-on, fluorescent nuclear stains with live cell compatibility. Org Lett 2013; 15:1330-3. [PMID: 23461418 DOI: 10.1021/ol400268t] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
DNA-binding, green and yellow fluorescent probes with excellent brightness and high on/off ratios are reported. The probes are membrane permeable, live-cell compatible, and optimally matched to 405 nm and 514 nm laser lines, making them attractive alternatives to UV-excited and blue emissive Hoechst 33342 and DAPI nuclear stains. Their electronic structure was investigated by optical spectroscopy supported by TD-DFT calculations. DNA binding is accompanied by 27- to 75-fold emission enhancements, and linear dichroism demonstrates that one dye is a groove binder while the other intercalates into DNA.
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Affiliation(s)
- Demar R G Pitter
- Department of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146, USA
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