Mannosylcalix[n]arenes as multivalent ligands for DC-SIGN.

Area of Science:

• Biochemistry
• Immunology
• Materials Science

Background:

• DC-SIGN (dendritic cell-specific intercellular contact-dependent adhesion molecule) is a C-type lectin receptor on dendritic cells crucial for immune response initiation.
• Human Immunodeficiency Virus (HIV) utilizes DC-SIGN's affinity for mannose-containing structures on its gp120 envelope protein to facilitate viral entry and T-cell infection.
• DC-SIGN functions as a tetramer, with clustered tetramers on the cell surface amplifying carbohydrate recognition, making it a significant target for antiviral strategies.

Purpose of the Study:

• To synthesize novel mannosylated calix[n]arene derivatives as potential multivalent inhibitors of DC-SIGN.
• To evaluate the inhibitory activity of these calixarenes against the binding of DC-SIGN to a mannosylated model of HIV gp120.
• To assess the potential of calixarene scaffolds for developing effective DC-SIGN-targeted antiviral therapies.

Main Methods:

• Synthesis of four mannosylated calix[n]arene compounds (1a-d).
• Surface Plasmon Resonance (SPR) competition assays were employed to measure the inhibition of DC-SIGN binding to mannosylated Bovine Serum Albumin (BSA).
• Calculation of IC50 values and relative potency (normalized for the number of mannose units) to quantify inhibitory efficacy.

Main Results:

• Mannosylated calix[n]arenes demonstrated inhibitory activity against DC-SIGN binding in the micromolar (μM) range.
• Compound 1a exhibited a moderate multivalent effect, with a relative potency (rp/n) of approximately 4 compared to monovalent methyl α-mannoside.
• The results suggest that calixarene scaffolds can effectively present multiple ligand units for DC-SIGN interaction.

Conclusions:

• Calix[n]arenes represent a promising scaffold for the development of multivalent inhibitors targeting DC-SIGN.
• The observed inhibitory activity supports the potential of these compounds in strategies aimed at blocking HIV entry mediated by DC-SIGN.
• Further development of calixarene-based inhibitors could lead to novel therapeutic approaches against HIV infection.