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J Allergy Clin Immunol. 2014 Jan;133(1):240-7.e1-3. doi: 10.1016/j.jaci.2013.05.018. Epub 2013 Jul 2.

Mice deficient in the St3gal3 gene product α2,3 sialyltransferase (ST3Gal-III) exhibit enhanced allergic eosinophilic airway inflammation.

Author information

1
Department of Medicine, Division of Allergy and Clinical Immunology, Johns Hopkins University School of Medicine, Baltimore, Md.
2
Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Md.
3
Department of Biochemistry, Emory University School of Medicine, Atlanta, Ga.
4
Department of Medicine, Division of Allergy and Clinical Immunology, Johns Hopkins University School of Medicine, Baltimore, Md. Electronic address: bbochner@jhmi.edu.

Abstract

BACKGROUND:

Sialic acid-binding immunoglobulin-like lectin (Siglec)-F is a proapoptotic receptor on mouse eosinophils, but little is known about its natural tissue ligand.

OBJECTIVE:

We previously reported that the St3gal3 gene product α2,3 sialyltransferase (ST3Gal-III) is required for constitutive Siglec-F lung ligand synthesis. We therefore hypothesized that attenuation of ST3Gal-III will decrease Siglec-F ligand levels and enhance allergic eosinophilic airway inflammation.

METHODS:

C57BL/6 wild-type mice and St3gal3 heterozygous or homozygous deficient (St3gal3(+/-) and St3gal3(-/-)) mice were used. Eosinophilic airway inflammation was induced through sensitization to ovalbumin (OVA) and repeated airway OVA challenge. Siglec-F human IgG1 fusion protein (Siglec-F-Fc) was used to detect Siglec-F ligands. Lung tissue and bronchoalveolar lavage fluid (BALF) were analyzed for inflammation, as well as various cytokines and chemokines. Serum was analyzed for allergen-specific immunoglobulin levels.

RESULTS:

Western blotting with Siglec-F-Fc detected approximately 500-kDa and approximately 200-kDa candidate Siglec-F ligands that were less abundant in St3gal3(+/-) lung extracts and nearly absent in St3gal3(-/-) lung extracts. After OVA sensitization and challenge, Siglec-F ligands were increased in wild-type mouse lungs but less so in St3gal3 mutants, whereas peribronchial and BALF eosinophil numbers were greater in the mutants, with the following rank order: St3gal3(-/-) ≥ St3gal3(+/-) > wild-type mice. Levels of various cytokines and chemokines in BALF were not significantly different among these 3 types of mice, although OVA-specific serum IgG1 levels were increased in St3gal3(-/-) mice.

CONCLUSIONS:

After OVA sensitization and challenge, St3gal3(+/-) and St3gal3(-/-) mice have more intense allergic eosinophilic airway inflammation and less sialylated Siglec-F ligands in their airways. One possible explanation for these findings is that levels of sialylated airway ligands for Siglec-F might be diminished in mice with attenuated levels of ST3Gal-III, resulting in a reduction in a natural proapoptotic pathway for controlling airway eosinophilia.

KEYWORDS:

6’-su-sLacNAc; 6′-Sulfated sialyl Lewis X; 6′-Sulfated sialyl N-acetyl-D-lactosamine; 6′-su-sLe(x); 6′-sulfated sialyl Lewis X; 6′-sulfated sialyl N-acetyl-D-lactosamine; BALF; Bronchoalveolar lavage fluid; Eosinophils; MBP; Major basic protein; OVA; Ovalbumin; ST3Gal-III; Sialic acid–binding immunoglobulin-like lectin; Siglec; Siglec-8 human IgG(1) Fc chimera; Siglec-8-Fc; Siglec-F; Siglec-F human IgG(1) Fc chimera; Siglec-F-Fc; St3gal3; St3gal3 gene product α2,3 sialyltransferase; WT; Wild-type; apoptosis; asthma; glycan ligands; lung

PMID:
23830412
PMCID:
PMC3874253
DOI:
10.1016/j.jaci.2013.05.018
[Indexed for MEDLINE]
Free PMC Article

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