Glycomics Studies on Nematodes Elucidate Conserved Functional Epitopes and Biosynthetic Pathways

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Nematodes constitute a large number of different species on earth and some are disease‐causing parasites of mammals. Glycoproteins synthesised by nematodes are decorated with a different set of glycan structures as compared to the ones produced by mammals. During the course of parasite‐host interactions, nematode glycans could trigger or modulate host immune responses. To better understand the conserved N‐glycosylation machinery in nematodes, we use the free‐living Caenorhabditis elegans as a model; double/triple mutants were generated to investigate the function of genes which are involved in N‐glycan biosynthesis. N‐glycans of C. elegans as well as parasitic nematodes were released, either enzymatically or chemically, fluorescently labelled and analysed in a great detail using off‐line HPLC‐MALDI‐TOF‐MS in combination with exo‐glycosidases and chemical treatments. Furthermore, a number of fucosyltransferases (FUTs), hexosaminidases and N‐acetylglucosyltransferases were cloned and recombinantly expressed so that their enzymatic activities were studied in vitro by glycan remodelling. A range of conserved functional epitopes on N‐glycans were characterised in C. elegans wild‐type and mutant strains and were also identified in parasitic species, such as Oesophagostomum dentatum and Haemonchus contortus; this includes different types of Gal‐Fuc modifications of the chitobiose core and phosphorylcholine substitution on the N‐acetylhexosamine residues of the antennae. The functions of three core‐modifying FUTs were elucidated by in vitro and glycomic analyses. Moreover, the rice PNGase A or hydrazine released more N‐glycans with complex core modifications, which are not observed before using traditional PNGase F and almond PNGase A. These data expand our knowledge on nematode N‐glycosylation, particularly the plasticity in producing rare structures when a biosynthetic pathway is disturbed. Identification of nematode‐specific glyco‐epitopes would facilitate the design of novel strategies for diagnosing parasitic infections and aid engineering of glyco‐vaccines in the future.Support or Funding InformationThe Austrian Fonds zur Förderung der wissenschaftlichen Forschung (FWF; grants P30021 to S.Y., P21946 and P25058 to K.P. and P23922 and P29466 to I.B.H.W.)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.