Skin-Homing Receptors on Effector Leukocytes Are Differentially Sensitive to Glyco-Metabolic Antagonism in Allergic Contact Dermatitis

Abstract

T cell recruitment into inflamed skin is dependent on skin-homing receptor binding to endothelial (E)- and platelet (P)-selectin. These T cell receptors, or E- and P-selectin ligands, can be targeted by the metabolic fluorosugar inhibitor, 4-F-GlcNAc, to blunt cutaneous inflammation. Compelling new data indicate that, in addition to T cells, NK cells are also recruited to inflamed skin in allergic contact hypersensitivity (CHS) contingent on E- and P-selectin-binding. Using a model of allergic CHS, we evaluated the identity and impact of NK cell E-selectin ligand(s) on inflammatory responses and examined the oral efficacy of 4-F-GlcNAc. We demonstrated that the predominant E-selectin ligands on NK cells are P-selectin glycoprotein ligand-1 and protease-resistant glycolipids. We showed that, unlike the induced E-selectin ligand expression on activated T cells upon exposure to Ag, ligand expression on NK cells was constitutive. CHS responses were significantly lowered by orally administered 4-F-GlcNAc treatment. Although E-selectin ligand on activated T cells was suppressed, ligand expression on NK cells was insensitive to 4-F-GlcNAc treatment. These findings indicate that downregulating effector T cell E- and P-selectin ligand expression directly correlates with anti-inflammatory efficacy and provides new insight on metabolic discrepancies of E-selectin ligand biosynthesis in effector leukocytes in vivo.

Metabolic Inhibition of Galectin-1-Binding Carbohydrates Accentuates Antitumor Immunity

“…4-F-GlcNAc has been shown to inhibit N-acetyllactosamine and Gal-1-binding determinant formation on membrane proteins expressed by T cells (Barthel et al, 2011) and on ovarian and colon cancer cells (Descheny et al, 2006; Dimitroff et al, 2003a; Dimitroff et al, 2003b; Gainers et al, 2007; Woynarowska et al, 1996; Woynarowska et al, 1994). Stability analysis of 4-F-GlcNAc in mouse plasma showed that the parent compound, fully acetylated 4-F-GlcNAc, exhibited a half life of ~2.3h, sufficient for uptake by relevant immune cells (Figure S1d).…”

“…To analyze the dependence of Gal-1-binding N-acetyllactosamines in Gal-1-mediated tumor immune evasion, we used a fluoro-glucosamine inhibitor of N-acetyllactosamine formation, 4-F-GlcNAc. This inhibitor prevents N-acetyllactosamine synthesis on N- and O-glycans in glyco-metabolically active immune cells and prevents consequent lectin-binding activity with relatively high specificity for Gal-1-binding determinants (Barthel et al, 2011; Descheny et al, 2006; Dimitroff et al, 2003a; Dimitroff et al, 2003b; Gainers et al, 2007; Woynarowska et al, 1996; Woynarowska et al, 1994). Importantly, in this report, we show that diminution of Gal-1 binding on activated T cells via 4-F-GlcNAc treatment can alleviate Gal-1-mediated T cell apoptotic activity.…”

“…Here, we show that limiting Gal-1-binding to N-acetyllactosamines on T cell membrane proteins with a well-characterized metabolic inhibitor of N-acetyllactosamines synthesis, 4-F-GlcNAc (Barthel et al, 2011; Descheny et al, 2006; Dimitroff et al, 2003b; Gainers et al, 2007; Woynarowska et al, 1996; Woynarowska et al, 1994), attenuated growth of B16 melanomas and EL-4 lymphomas through enhancement of anti-tumor immune responses. 4-F-GlcNAc treatment inhibited Gal-1-binding N-acetyllactosamine formation on effector T and NK cells, which prevented Gal-1-induced apoptosis and caused concomitant increases in melanoma-specific CTLs and IFN-γ levels.…”

Alpha 1,3 fucosyltransferases are master regulators of prostate cancer cell trafficking

“…PC-3 empty or FT cells stably expressing EGFP were injected into the left ventricle of Rag2/Janus kinase(Jak)-3 double null mice deficient in T, B, and NK cells (Fig. S4) (26,27), and analyzed over a 24 h period for PCa cell retention in BM, lungs. and spleen.…”

Fluorinated per-acetylated GalNAc metabolically alters glycan structures on leukocyte PSGL-1 and reduces cell binding to selectins

“…This molecule reduces selectin-mediated cutaneous lymphocyte-associated antigen (CLA ϩ ) T-cell adhesion in vitro, 28 and in in vivo models of skin inflammation. [29][30][31] Because O-linked glycans linked to PSGL-1 and other glycoproteins participate as important selectin ligands and because the attachment of GalNAc to serine/threonine residues on the peptide backbone is critical for the initiation of O-glycan assembly, we tested the hypothesis that modified monosaccharides based on GalNAc may be used to disrupt/alter the pattern of O-linked glycosylation. This can result in reduced selectin binding function.…”