Lectin-mediated protocell crosslinking to mimic cell-cell junctions and adhesion

Sarah Villringer,Winfried Römer,Taras Sych,Christina Manner,Anne Imberty,Josef Madl

doi:10.1038/s41598-018-20230-6

Abstract

Cell adhesion is a crucial feature of all multicellular organisms, as it allows cells to organise themselves into tissues to carry out specific functions. Here, we present a mimetic approach that uses multivalent lectins with opposing binding sites to crosslink glycan-functionalised giant unilamellar vesicles. The crosslinking process drives the progression from contact puncta into elongated protocellular junctions, which form the vesicles into polygonal clusters resembling tissues. Due to their carbohydrate specificity, different lectins can be engaged in parallel with both natural and synthetic glycoconjugates to generate complex interfaces with distinct lectin domains. In addition, the formation of protocellular junctions can be combined with adhesion to a functionalised support by other ligand-receptor interactions to render increased stability against fluid flow. Furthermore, we consider that adhesion is a complex process of attraction and repulsion by doping the vesicles with a PEG-modified lipid, and demonstrate a dose-dependent decrease of lectin binding and formation of protocellular junctions. We suggest that the engineering of prototissues through lectin-glycan interactions is an important step towards synthetic minimal tissues and in designing artificial systems to reconstruct the fundamental functions of biology.

Highlights

Synthetic biology combines the expertise from diverse disciplines and comes with different visions[1,2]
Selective lectin-glycan interactions induce protocell crosslinking, which results in the formation of prototissues with protocellular junctions
When a lectin with opposing binding sites such as LecA diffuses into the contact area of two adjacent vesicles, the free binding sites that are potentially oriented away from the first membrane can bind to Gb3 molecules of the second giant unilamellar vesicles (GUVs)

Summary

Introduction

Synthetic biology combines the expertise from diverse disciplines and comes with different visions[1,2]. Several studies used GUVs to further analyse the receptor binding of e.g. a glycolipid bearing sialyl LewisX (SLeX) to its ligand E-selectin immobilised on planar surfaces or in solution, to investigate the biophysics of cell adhesion (reviewed by Fenz & Sengupta[19]). Those interactions have not been used to construct larger vesicle networks. The latter generates the important interplay of specific interaction and unspecific repulsion which both contribute to the complex process of cell adhesion and interaction

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