Efficient inhibition of O-glycan biosynthesis using the hexosamine analog Ac5GalNTGc. Issue 5 (20th May 2021)

• Record Type: Journal Article
• Authors: Wang, Shuen-Shiuan; Solar, Virginia del; Yu, Xinheng; Antonopoulos, Aristotelis; Friedman, Alan E.; Agarwal, Kavita; Garg, Monika; Ahmed, Syed Meheboob; Addhya, Ahana; Nasirikenari, Mehrab; Lau, Joseph T.; Dell, Anne; Haslam, Stuart M.; Sampathkumar, Srinivasa-Gopalan; Neelamegham, Sriram
• Is Part Of: Cell chemical biology. Volume 28:Issue 5(2021)
• Page Start: 699
• Page End: 710.e5
• Publication Date: 2021-05-20
• Subjects: glycosylation -- O-glycan -- mucin -- inhibitor -- neutrophil -- cell adhesion -- small molecule -- inflammation -- sialyl-Lewis X -- selectin; Biochemistry -- Periodicals; 572.05
• DOI: 10.1016/j.chembiol.2021.01.017
• Languages: English
• ISSNs: 2451-9456

Abstract

Summary: There is a critical need to develop small-molecule inhibitors of mucin-type O -linked glycosylation. The best-known reagent currently is benzyl-GalNAc, but it is effective only at millimolar concentrations. This article demonstrates that Ac5 GalNTGc, a peracetylated C-2 sulfhydryl-substituted GalNAc, fulfills this unmet need. When added to cultured leukocytes, breast cells, and prostate cells, Ac5 GalNTGc increased cell-surface VVA binding by ∼10-fold, indicating truncation of O-glycan biosynthesis. Cytometry, mass spectrometry, and western blot analysis of HL-60 promyelocytes demonstrated that 50–80 μM Ac5 GalNTGc prevented elaboration of 30%–60% of the O-glycans beyond the Tn-antigen (GalNAcα1-Ser/Thr) stage. The effect of the compound on N-glycans and glycosphingolipids was small. Glycan inhibition induced by Ac5 GalNTGc resulted in 50%–80% reduction in leukocyte sialyl-Lewis X expression and L-/P-selectin-mediated rolling under flow conditions. Ac5 GalNTGc was pharmacologically active in mouse. It reduced neutrophil infiltration to sites of inflammation by ∼60%. Overall, Ac5 GalNTGc may find diverse applications as a potent inhibitor of O-glycosylation. Graphical abstract: Highlights: We describe a potent inhibitor of mucin-type O-linked glycosylation, Ac5 GalNTGc Ac5 GalNTGc (50–80 μM) blocks core 1 O-glycan extension in diverse cell types Ac5 GalNTGc reduces leukocyte selectin binding function ex vivo under fluid shear It is pharmacologically active, reducing leukocyte homing to sites of inflammation Abstract : Chemical inhibitors to block O-linked glycosylation are currently lacking. Wang et al. show that Ac5 GalNTGc fills this gap. This reagent blocks O-glycan biosynthesis at the GalNAcα-Ser/Thr stage, preventing sialyl-Lewis X formation on selectin ligands. It is pharmacologically active in mouse inflammation models. Ac5 GalNTGc will be valuable for studies of O-glycan/mucin biology.