CellFy: a cell-based fragment screen against C-type lectins

Item Type:	Article
Title:	CellFy: a cell-based fragment screen against C-type lectins
Creators Name:	Schulze, J. and Baukmann, H. and Wawrzinek, R. and Fuchsberger, F. and Specker, E. and Aretz, J. and Nazaré, M. and Rademacher, C.
Abstract:	Fragment-based drug discovery is a powerful complement to conventional high-throughput screening, especially for difficult targets. Screening low molecular weight fragments usually requires highly sensitive biophysical methods due to the generally low affinity of the identified ligands. Here, we de-veloped a cell-based fragment screening assay (cellFy) that allows sensitive identification of fragment hits in a physiologically more relevant environment in contrast to isolated target screenings in solution. For this a fluorescently labelled multivalent reporter was employed, enabling direct measurement of displacement by low molecular weight fragments without requiring enzymatic reactions or receptor activation. We applied this technique to identify hits against two challenging targets of the C-type lectin receptor (CLR) family: Dendritic Cell-Specific Intercellular adhesion molecule-3-Grabbing Non-integrin (DC-SIGN) and Langerin. Both receptors are involved in pathogen recognition and initiation of an immune response, which renders them attractive targets for immune modulation. Due to their shallow and hydrophilic primary binding site, hit identification for CLRs is challenging and drug-like ligands for CLRs are sparse. Screening of a fragment library followed by hit validation identified several promising candidates for further fragment evolution for DC-SIGN. Additionally, a multiplexed assay format was developed for simultaneous screening against multiple CLRs allowing a selectivity counterscreening. Overall, this sensitive cell-based fragment screening assay provides a powerful tool for rapid identification of bioactive fragments, even for difficult targets.
Keywords:	C-Type Lectins, CD Antigens, Cell Adhesion Molecules, Cell Line, Cell Surface Receptors, Dextrans, Drug Discovery, Flow Cytometry, Ligands, Mannose-Binding Lectins, Molecular Structure, Preclinical Drug Evaluation, Protein Binding, Small Molecule Libraries, Structure-Activity Relationship, Surface Antigens
Source:	ACS Chemical Biology
ISSN:	1554-8929
Publisher:	American Chemical Society
Volume:	13
Number:	12
Page Range:	3229-3235
Date:	December 2018
Official Publication:	https://doi.org/10.1021/acschembio.8b00875
PubMed:	View item in PubMed

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