Unprecedented Thiacalixarene Fucoclusters as Strong Inhibitors of Ebola cis-Cell Infection and HCMV-gB Glycoprotein/DC-SIGN C-type Lectin Interaction

Abstract

Glycan-protein interactions control numerous biological events from cell-cell recognition and signaling to pathogen host cell attachment for infections. To infect cells, some viruses bind to immune cells thanks to DC-SIGN (dendritic cell [DC]-specific ICAM3-grabbing non-integrin) C-type lectin expressed on dendritic and macrophage cell membrane, via their envelope protein. Prevention of this infectious interaction is a serious therapeutic option. Here, we describe the synthesis of first water-soluble tetravalent fucocluster pseudopeptide-based thiacalixarene 1,3-alternate as viral antigen mimics designed for the inhibition of DC-SIGN, to prevent viral particle uptake. Their preparation exploits straightforward convergent strategies involving one pot Ugi four-component (Ugi-4CR) and azido-alkyne click chemistry reactions as key steps. Surface plasmon resonance showed strong inhibition of DC-SIGN interaction properties by tetravalent ligands designed with high relative potencies and β avidity factors. All ligands block DC-SIGN active sites at nanomolar IC 50 preventing cis-cell infection by Ebola viral particles pseudotyped with EBOV glycoprotein (Zaïre species of Ebola virus) on Jurkat cells that express DC-SIGN. In addition, we observed strong inhibition of DC-SIGN/human cytomegalovirus (HCMV)-gB recombinant glycoprotein interaction. This finding opens the way to the simple development of new models of water-soluble glycocluster-based thia-calixarene with wide-range antimicrobial activities.

Development of C-type lectin-oriented surfaces for high avidity glycoconjugates: towards mimicking multivalent interactions on the cell surface

“…The architectural organization of thiacalixarene displaying 4 carbohydrate-based ligands (Figure 8) is considered as potent inhibitors of DC-SIGN in the case of Ebola infection assays. (13) The IC50 values (Table 2), extracted from a SPR inhibition assay, showed a valuable relative affinity for DC-SIGN (IC50 values from 17 to 26.5 µM) with only 4 fucose-derivative ligands. However, no significant difference is observed between two different topologies of calixarenes (compound 5 (Thiacalix) and 7 (Calix)).…”

“…However, for compounds with an affinity below to 10 µM (case of glycoclusters) and able to display higher level of multivalency, the affinity determination should be exclusively determined by direct interaction over an oriented DC-SIGN S-ECD surface. Indeed, displaying 4 fucoses, these compounds have probably access to the same level of multivalency when DC-SIGN is in solution (13) and onto the surface. On the contrary, compounds with scaffolds 3 and 4, with 16 ligands, fully benefit from the surface avidity effect.…”

Development of c-type lectin oriented surfaces for high avidity glycoconjugates: towards mimicking multivalent interactions on the cell surface

“…(2)(3)(4) These findings have placed DC-SIGN as an important therapeutic target and many efforts are being invested to develop DC-SIGN antagonists. (5)(6)(7)(8)(9)(10)(11)(12)(13) DC-SIGN is a tetrameric C-type lectin receptor (CLR) with specificity to D-mannose-and L-fucose-containing oligosaccharides that bind the C-terminal carbohydrate recognition domain (CRD) in a Ca2+-dependent manner. (1,14) Although the intrinsic affinity of a single CRD for a monosaccharide is low (KD in mM range), the global DC-SIGN/multivalent carbohydrates interaction affinity is markedly amplified (KD from µM to pM) through the avidity phenomenon.…”

Multivalent and Multifunctional Calixarenes in Bionanotechnology

“…However, experiments with Langerin were not performed because, unfortunately, only a weak binding to DC-SIGN was observed without any particular difference among the mannosylated calixarenes. Very recently, Fieschi et al [64] explored the possibility to block the infection by Ebola virus targeting DC-SIGN receptor with a calix [4]arene bearing four units of L-fucose. Interestingly, this cluster exhibits an IC 50 of 218 nM, resulting a stronger inhibitor than dendrimers with higher densities of mannose units.…”