Modulating Cell‐Surface Receptor Signaling and Ion Channel Functions by In Situ Glycan Editing

Abstract

Glycans anchored on cell-surface receptors are active modulators of receptor signaling. A strategy is presented that enforces transient changes to cell-surface glycosylation patterns to tune receptor signaling. This approach, termed in situ glycan editing, exploits recombinant glycosyltransferases to incorporate monosaccharides with linkage specificity onto receptors in situ. α2,3-linked sialic acid or α1,3-linked fucose added in situ suppresses signaling through epidermal growth factor receptor and fibroblast growth factor receptor. We also applied the same strategy to regulate the electrical signaling of a potassium ion channel–human ether-à-go-go-related gene channel. Compared to gene editing, no long-term perturbations are introduced to the treated cells. In situ glycan editing therefore offers a promising approach for studying the dynamic role of specific glycans in membrane receptor signaling and ion channel functions.

Finding the sweet spot: glycosylation mediated regulation of intestinal inflammation

“…Epithelial glycans in the intestine serve as ligands that induce host immune signaling and act as nutrients that regulate gut microbial composition 24 – 30 . Furthermore, recent studies have highlighted that human and murine small intestinal Paneth cells express specific N-Acetyllactosamine (Galβ1-4GlcNAc, LacNAc) glycans that control growth and differentiation of adjacent stem cells, a critical event for ongoing intestinal epithelial self-renewal 31 , 32 . Therefore, intestinal epithelial glycans play an essential role in integrating host, microbial, and environmental cues to maintain mucosal homeostasis.…”

Engineered Glycocalyx Regulates Stem Cell Proliferation in Murine Crypt Organoids

“…Following these pioneering studies, our laboratory developed a method for in situ fucosylation of cell-surface glycans that exploits the use of a recombinant Helicobacter pylori α1,3 fucosyltransferase (ɑ1,3 FucT) to transfer fucose or a fucose analogue from a GDP-Fucose donor onto type II N -acetyllactosamine (LacNAc) to generate the Lewis X (Le X ) trisaccharide (Figure 1A) (Zheng et al, 2011). This technique has been used to modify cell-surface glycosylation patterns (Jiang et al, 2017) or to introduce a tag via a fucose analogue that can be further derivatized for visualizing the labeled LacNAc-containing glycoconjugates (Jiang et al, 2014; Zheng et al, 2011). This approach has also been translated into a histological protocol to characterize glycosylation patterns in tissue sections; in this form, the method is termed Chemoenzymatic Histology of Membrane Polysaccharides (CHoMP) (Rouhanifard et al, 2014).…”

“…Here we apply this in situ glycan editing method (Jiang et al, 2017) to crypt organoids to study the impact of glycosylation on stem cell proliferation and differentiation in a complex, multicellular system. Using this approach, we uncovered a pattern of high LacNAc expression on the surface of Paneth cells.…”

For Wnt Signaling, Fucosylation of LRP6 Is a Bitter Pill

“…Recent efforts to chemoenzymatically remodel the glycocalyx, notably by using sialidases to remove sialic acid residues, have proven highly powerful and exhibit great translational potential (Xiao et al, 2016). The current study suggests a complementary approach, that glycan editing using a glycosyltransferase and its nucleotide sugar donor, rather than a glycosidase, may be therapeutically beneficial to downregulate pathogenic Wnt signaling (Jiang et al, 2018). Significant hurdles remain, including selective and concurrent delivery of both the macromolecular enzyme and its small-molecule substrate to the tissue of interest, as well as methods to ensure minimal effects on non-diseased tissues.…”