TETRALEC, Artificial Tetrameric Lectins: A Tool to Screen Ligand and Pathogen Interactions.

Silvia Achilli,Christine Ebel,Sabine Mayer-Lambertz,Michel Thépaut,João T Monteiro,Franck Fieschi,Niels-Christian Reichardt,Sonia Serna,Aline Le Roy,Corinne Vivès,Bernd Lepenies

doi:10.3390/ijms21155290

Abstract

C-type lectin receptor (CLR)/carbohydrate recognition occurs through low affinity interactions. Nature compensates that weakness by multivalent display of the lectin carbohydrate recognition domain (CRD) at the cell surface. Mimicking these low affinity interactions in vitro is essential to better understand CLR/glycan interactions. Here, we present a strategy to create a generic construct with a tetrameric presentation of the CRD for any CLR, termed TETRALEC. We applied our strategy to a naturally occurring tetrameric CRD, DC-SIGNR, and compared the TETRALEC ligand binding capacity by synthetic N- and O-glycans microarray using three different DC-SIGNR constructs i) its natural tetrameric counterpart, ii) the monomeric CRD and iii) a dimeric Fc-CRD fusion. DC-SIGNR TETRALEC construct showed a similar binding profile to that of its natural tetrameric counterpart. However, differences observed in recognition of low affinity ligands underlined the importance of the CRD spatial arrangement. Moreover, we further extended the applications of DC-SIGNR TETRALEC to evaluate CLR/pathogens interactions. This construct was able to recognize heat-killed Candida albicans by flow cytometry and confocal microscopy, a so far unreported specificity of DC-SIGNR. In summary, the newly developed DC-SIGNR TETRALEC tool proved to be useful to unravel novel CLR/glycan interactions, an approach which could be applied to other CLRs.

Highlights

Glycans play critical roles in many biological processes ranging from the maintenance of cell or tissue structure, molecular signal transduction, to cell recognition
C-type lectin receptors (CLRs) are carbohydrate-binding proteins that are involved in the recognition and the uptake of altered-self and non-self glycans through their Ca2+ dependent carbohydrate recognition domain (CRD) [3]
The strategy proposed enables the irreversible functionalization of CLR CRD N-terminus with a biotin moiety and thereafter, by coupling to a NeutrAvidin molecule the generation of artificial tetrameric CLRs

Summary

Introduction

Glycans play critical roles in many biological processes ranging from the maintenance of cell or tissue structure, molecular signal transduction, to cell recognition. Many cell-cell interactions are carbohydrate driven [1] Detection of pathogens such as viruses, fungi and bacteria is mediated by the recognition of glycans expressed on the microorganism surface. The human immune system possesses pattern recognition receptors (PRRs), expressed on dendritic cells, which are able to recognize molecular motifs and activate immunity [2]. Amongst those receptors, C-type lectin receptors (CLRs) are carbohydrate-binding proteins that are involved in the recognition and the uptake of altered-self and non-self glycans through their Ca2+ dependent carbohydrate recognition domain (CRD) [3]. The crucial roles of CLRs in the balance of immunity make CLR-glycan interactions attractive for pharmaceutical interventions [4]

Methods

Findings

Discussion

Conclusion