- Poly-(amidoamine) dendrimers with a precisely core positioned sulforhodamine B molecule for comparative biological tracing and profiling
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We report on a simple robust procedure for synthesis of generation-4 poly-(amidoamine) (PAMAM) dendrimers with a precisely core positioned single sulforhodamine B molecule. The labelled dendrimers exhibited high fluorescent quantum yields where the absorbance and fluorescence spectrum of the fluorophore was not affected by pH and temperature. Since the stoichiometry of the fluorophore to the dendrimer is 1:1, we were able to directly compare uptake kinetics, the mode of uptake, trafficking and safety of dendrimers of different end-terminal functionality (carboxylated vs. pyrrolidonated) by two phenotypically different human endothelial cell types (the human brain capillary endothelial cell line hCMEC/D3 and human umbilical vein endothelial cells), and without interference of the fluorophore in uptake processes. The results demonstrate comparable uptake kinetics and a predominantly clathrin-mediated endocytotic mechanism, irrespective of dendrimer end-terminal functionality, where the majority of dendrimers are directed to the endo-lysosomal compartments in both cell types. A minor fraction of dendrimers, however, localize to endoplasmic reticulum and the Golgi apparatus, presumably through the recycling endosomes. In contrast to amino-terminated PAMAM dendrimers, we confirm safety of carboxylic acid- and pyrrolidone-terminated PAMAM dendrimers through determination of cell membrane integrity and comprehensive respiratory profiling (measurements of mitochondrial oxidative phosphorylation and determination of its coupling efficiency). Our dendrimer core-labelling approach could provide a new conceptual basis for improved understanding of dendrimer performance within biological settings.
- Wu, Lin-Ping,Ficker, Mario,Mejls?e, S?ren L.,Hall, Arnaldur,Paolucci, Valentina,Christensen, J?rn B.,Trohopoulos, Panagiotis N.,Moghimi, Seyed M.
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- Chemical Targeting of Voltage Sensitive Dyes to Specific Cells and Molecules in the Brain
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Voltage sensitive fluorescent dyes (VSDs) are important tools for probing signal transduction in neurons and other excitable cells. The impact of these highly lipophilic sensors has, however, been limited due to the lack of cell-specific targeting methods in brain tissue or living animals. We address this key challenge by introducing a nongenetic molecular platform for cell- and molecule-specific targeting of synthetic VSDs in the brain. We employ a dextran polymer particle to overcome the inherent lipophilicity of VSDs by dynamic encapsulation and high-affinity ligands to target the construct to specific neuronal cells utilizing only native components of the neurotransmission machinery at physiological expression levels. Dichloropane, a monoamine transporter ligand, enables targeting of dense dopaminergic axons in the mouse striatum and sparse noradrenergic axons in the mouse cortex in acute brain slices. PFQX in conjunction with ligand-directed acyl imidazole chemistry enables covalent labeling of AMPA-type glutamate receptors in the same brain regions. Probe variants bearing either a classical electrochromic ANEP dye or state-of-the-art VoltageFluor-type dye respond to membrane potential changes in a similar manner to the parent dyes, as shown by whole-cell patch recording. We demonstrate the feasibility of optical voltage recording with our probes in brain tissue with one-photon and two-photon fluorescence microscopy and define the signal limits of optical voltage imaging with synthetic sensors under a low photon budget determined by the native expression levels of the target proteins. This work demonstrates the feasibility of a chemical targeting approach and expands the possibilities of cell-specific imaging and pharmacology.
- Fiala, Tomas,Wang, Jihang,Dunn, Matthew,?ebej, Peter,Choi, Se Joon,Nwadibia, Ekeoma C.,Fialova, Eva,Martinez, Diana M.,Cheetham, Claire E.,Fogle, Keri J.,Palladino, Michael J.,Freyberg, Zachary,Sulzer, David,Sames, Dalibor
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supporting information
p. 9285 - 9301
(2020/06/04)
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- α-Synuclein Dimers as Potent Inhibitors of Fibrillization
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Aggregation of the neuronal protein α-synuclein into amyloid fibrils plays a central role in the development of Parkinson's disease. Growth of fibrils can be suppressed by blocking fibril ends from their interaction with monomeric proteins. In this work, we constructed inhibitors that bind to the ends of α-synuclein amyloid fibrils with very high affinity. They are based on synthetic α-synuclein dimers and interact with fibrils via two monomeric subunits adopting conformation that efficiently blocks fibril elongation. By tuning the charge of dimers, we further enhanced the binding affinity and prepared a construct that inhibits fibril elongation at nanomolar concentration (IC50 ≈ 20 nM). To the best of our knowledge, it is the most efficient inhibitor of α-synuclein fibrillization.
- Kyriukha, Yevhenii A.,Afitska, Kseniia,Kurochka, Andrii S.,Sachan, Shubhra,Galkin, Maksym,Yushchenko, Dmytro A.,Shvadchak, Volodymyr V.
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- Novel xanthene based dyes, colored photosensitive resin composition including the same and color filter manufactured by using this
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The present invention relates to a xanthene-based dye, a colored photosensitive resin composition including the same, and a color filter manufactured by using a colored photosensitive resin. The xanthene-based dye of the present invention is excellent in heat resistance, color characteristics, molar absorptivity, and compatibility with pigments, and thus can produce color filters excellent in brightness, color sharpness, and durability.COPYRIGHT KIPO 2018
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Paragraph 0091-0092
(2018/05/03)
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- Selective fluorescent nonpeptidic antagonists for vasopressin V2 GPCR: Application to ligand screening and oligomerization assays.
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A series of fluorescent benzazepine ligands for the arginine-vasopressin V2 receptor (AVP V2R) was synthesized using "Click" chemistry. Their in vitro pharmacological profile at AVP V2R, V1aR, V1bR, and oxytocin receptor was measured by binding assay and functional studies. Compound 9p, labeled with Lissamine Rhodamine B using novel solid-phase organic tagging (SPOrT) resin, exhibited a high affinity for V2R (4.0 nM), an excellent selectivity toward V2R and antagonist properties. By changing the nature of the dye, DY647 and Lumi4-Tb probes 44 and 47 still display a high affinity for V2R (5.6 and 5.8 nM, respectively). These antagonists constitute the first high-affinity selective nonpeptidic fluorescent ligands for V 2R. They enabled the development of V2R time-resolved FRET-based assay readily amenable to high-throughput screening. Taking advantage of their selectivity, these compounds were also successfully involved in the study of V1aR-V2R dimerization on cell surface.
- Loison, Stéphanie,Cottet, Martin,Orcel, Hélène,Adihou, Hélène,Rahmeh, Rita,Lamarque, Laurent,Trinquet, Eric,Kellenberger, Esther,Hibert, Marcel,Durroux, Thierry,Mouillac, Bernard,Bonnet, Dominique
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supporting information
p. 8588 - 8602
(2013/01/15)
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- Scalable synthesis of lissamine rhodamine B sulfonyl chloride and incorporation of xanthene derivatives onto polymer supports
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A scalable synthetic route to lissamine rhodamine B sulfonyl chloride has been developed and a series of monomeric derivatives of this xanthene dye have been synthesized. Their subsequent incorporation into polymer supports has been accomplished and led to improved thermal stability for the conjugates as compared to the free dye. Georg Thieme Verlag Stuttgart.
- Yang, Hua,Vasudevan, Sundar,Oriakhi, Christopher O.,Shields, Jay,Carter, Rich G.
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p. 957 - 961
(2008/12/21)
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