Human Milk Oligosaccharide 2'-fucosyllactose inhibits ligand binding to C-type lectin DC-SIGN but not to Langerin

Mukherjee, R.; Somovilla, V. J.; Chiodo, F.; Bruijns, S.; Pieters, R. J.; Garssen, J.; van Kooyk, Y.; BERGENHENEGOUWEN, J. v.; Kraneveld, A.

doi:10.1101/2022.07.27.501236

bioRxiv · 10.1101/2022.07.27.501236

Human Milk Oligosaccharide 2'-fucosyllactose inhibits ligand binding to C-type lectin DC-SIGN but not to Langerin

Mukherjee, R.·Somovilla, V. J.·Chiodo, F.·Bruijns, S.·Pieters, R. J.·Garssen, J.·van Kooyk, Y.·BERGENHENEGOUWEN, J. v.·Kraneveld, A.

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Abstract

Human milk oligosaccharides (HMOs) and its most abundant component, 2-Fucosyllactose (2-FL), are known to be immunomodulatory. Previously, it was shown that HMOs and 2-FL bind to the C-type lectin receptor DC-SIGN. Here we show, using a ligand-receptor competition assay, that a whole mixture of HMOs from pooled human milk (HMOS) and 2-FL inhibit the binding of the carbohydrate-binding receptor DC-SIGN to its prototypical ligands, fucose and the oligosaccharide Lewis-B, (Leb) in a dose-dependent way. Interestingly, such inhibition by HMOS and 2-FL was not detected for another C-type lectin, Langerin, evolutionary similar to DC-SIGN. The cell-ligand competition assay using DC-SIGN expressing cells confirmed that 2-FL inhibits the binding of DC-SIGN to Leb. Molecular dynamics (MD) simulations show that 2-FL exists in a preorganized bioactive conformation before binding to DC-SIGN and this conformation is retained after binding to DC-SIGN. Leb has more flexible conformations and utilizes two binding modes, which operate one at a time via its two fucoses to bind to DC-SIGN. 2-FL may have a reduced entropic penalty due to its preorganized state compared to Leb, and it has lower binding enthalpy, suggesting better binding to DC-SIGN. Thus, due to the better binding to DC-SIGN, 2-FL may replace Leb from its binding pocket in DC-SIGN. MD simulations also showed that 2-FL does not bind to Langerin. Our studies confirm 2-FL as a specific ligand for DC-SIGN and suggest that 2-FL can replace other DC-SIGN ligands from its binding pocket during ligand-receptor interactions in possible immunomodulatory processes.

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Mukherjee, R., Somovilla, V. J., Chiodo, F., Bruijns, S., Pieters, R. J., Garssen, J., van Kooyk, Y., BERGENHENEGOUWEN, J. v., Kraneveld, A.. 2022-07-27. Human Milk Oligosaccharide 2'-fucosyllactose inhibits ligand binding to C-type lectin DC-SIGN but not to Langerin. https://doi.org/10.1101/2022.07.27.501236

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