Tsetse salivary glycoproteins are modified with paucimannosidic N-glycans, are recognised by C-type lectins and bind to trypanosomes

Kozak, R. P.; Mondragon-Shem, K.; Williams, C.; Rose, C.; Perally, S.; Caljon, G.; van den abbeele, J.; Wongtrakul-Kish, K.; Gardner, R.; Spencer, D.; Lehane, M. J.; Acosta-Serrano, A.

doi:10.1101/2020.06.25.172007

bioRxiv · 10.1101/2020.06.25.172007

Tsetse salivary glycoproteins are modified with paucimannosidic N-glycans, are recognised by C-type lectins and bind to trypanosomes

Kozak, R. P.·Mondragon-Shem, K.·Williams, C.·Rose, C.·Perally, S.·Caljon, G.·van den abbeele, J.·Wongtrakul-Kish, K.·Gardner, R.·Spencer, D.·Lehane, M. J.·Acosta-Serrano, A.

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Abstract

African sleeping sickness is caused by Trypanosoma brucei, a parasite transmitted by the bite of a tsetse fly. Trypanosome infection induces a severe transcriptional downregulation of tsetse genes encoding for salivary proteins, which reduces its anti-hemostatic and anti-clotting properties. To better understand trypanosome transmission and the possible role of glycans in insect bloodfeeding, we characterized the N-glycome of tsetse saliva glycoproteins. Tsetse salivary N-glycans were enzymatically released, tagged with either 2-aminobenzamide (2-AB) or procainamide, and analyzed by HILIC-UHPLC-FLR coupled online with positive-ion ESI-LC-MS/MS. We found that the N-glycan profiles of T. brucei-infected and naive tsetse salivary glycoproteins are almost identical, consisting mainly (>50%) of highly processed Man3GlcNAc2 in addition to several other paucimannose, high mannose, and few hybrid-type glycans. In overlay assays, these sugars were differentially recognized by the C-type lectins mannose receptor and DC-SIGN. We also show that salivary glycoproteins bind strongly to the surface of transmissible metacyclic trypanosomes. We suggest that although the repertoire of tsetse salivary N-glycans does not change during a trypanosome infection, the interactions with mannosylated glycoproteins may influence parasite transmission into the vertebrate host.

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Kozak, R. P., Mondragon-Shem, K., Williams, C., Rose, C., Perally, S., Caljon, G., van den abbeele, J., Wongtrakul-Kish, K., Gardner, R., Spencer, D., Lehane, M. J., Acosta-Serrano, A.. 2020-06-27. Tsetse salivary glycoproteins are modified with paucimannosidic N-glycans, are recognised by C-type lectins and bind to trypanosomes. https://doi.org/10.1101/2020.06.25.172007

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