Functional characterization of Schistosoma mansoni fucosyltransferases in Nicotiana benthamiana plants

Abstract

Helminth parasites secrete a wide variety of immunomodulatory proteins and lipids to dampen host immune responses. Many of these immunomodulatory compounds are modified with complex sugar structures (or glycans), which play an important role at the host–parasite interface. As an example, the human blood fluke Schistosoma mansoni produces highly fucosylated glycan structures on glycoproteins and glycolipids. Up to 20 different S. mansoni fucosyltransferase (SmFucT) genes can be found in genome databases, but thus far only one enzyme has been functionally characterized. To unravel the synthesis of highly fucosylated N-glycans by S. mansoni, we examined the ability of ten selected SmFucTs to modify N-glycans upon transient expression in Nicotiana benthamiana plants. All enzymes were localized in the plant Golgi apparatus, which allowed us to identify the SmFucTs involved in core fucosylation and the synthesis of complex antennary glycan motifs. This knowledge provides a starting point for investigations into the role of specific fucosylated glycan motifs of schistosomes in parasite-host interactions. The functionally characterized SmFucTs can also be applied to synthesize complex N-glycan structures on recombinant proteins to study their contribution to immunomodulation. Furthermore, this plant expression system will fuel the development of helminth glycoproteins for pharmaceutical applications or novel anti-helminth vaccines.

β-Hexosaminidases Along the Secretory Pathway of Nicotiana benthamiana Have Distinct Specificities Toward Engineered Helminth N-Glycans on Recombinant Glycoproteins

“…The ability of HEXO2B and HEXO3A to process non-endogenous glycans hints toward a role in defense against invading organisms that do have LDN-glycans. The interplay of pathogen/parasite-associated glycans with plant immunity is a fairly unexplored research area, which is in contrast to the strong focus on glycans in research regarding animal parasitic worms (Hokke and Yazdanbakhsh, 2005;Tundup et al, 2012). A role for HEXOs in plant defense responses is further supported by the chitinolytic activity of several plant HEXOs (Gutternigg et al, 2007;Strasser et al, 2007;Ryšlavá et al, 2014;Hyskova, 2015).…”

“…For example, typical mammalian glycan modifications that are shared with certain helminth N-glycans can be synthesized in N. benthamiana, such as core α1,6-fucosylation (Castilho et al, 2011a;Wilbers et al, 2016), additional branching (Castilho et al, 2011b), extension of antennae with β1,4-galactose, or Lewis X (Bakker et al, 2001;Rouwendal et al, 2009;Castilho et al, 2011a;Wilbers et al, 2017). In addition to humanized N-glycan engineering, several complex helminth glycan motifs, like LDN, LDN-F, and F-LDN-F, have previously been synthesized in N. benthamiana (Wilbers et al, 2017;van Noort et al, 2020). Finally, the availability of transgenic N. benthamiana plants that lack the typical plant sugar residues β1,2-xylose and/or core α1,3-fucose enable even greater flexibility of glyco-engineering strategies (Strasser et al, 2008;Jansing et al, 2019).…”

Contributions of the international plant science community to the fight against infectious diseases in humans—part 2: Affordable drugs in edible plants for endemic and re‐emerging diseases

“…Although N. benthamiana provides an efficient platform for the expression of glyco-engineered proteins, the diverse and complex glycan structures of helminths are poorly understood. Here, also plants can offer a helping hand, as shown by the functional characterization of 10 S. mansoni fucosyltransferases by transient expression in N. benthamiana, allowing the synthesis of the helminth glycan motif F-LDN-F (van Noort et al, 2020).…”

“…Here, also plants can offer a helping hand, as shown by the functional characterization of 10 S . mansoni fucosyltransferases by transient expression in N. benthamiana , allowing the synthesis of the helminth glycan motif F‐LDN‐F (van Noort et al ., 2020 ).…”

Schistosoma mansoni α-N-acetylgalactosaminidase (SmNAGAL) regulates coordinated parasite movement and egg production

“…Regardless of their significance in orchestrating these heterospecific, conspecific or developmental activities, the gene products responsible for schistosome glycoprotein and glycolipid anabolism and degradation are only slowly being characterised [16,17]. One such glycogene family, critical to glycosylation homeostasis in other eukaryotes, is the glycosyl hydrolases (or glycoside hydrolases, GH).…”