title: Mice deficient in the St3gal3 gene product α2,3 sialyltransferase (ST3Gal-III) exhibit enhanced allergic eosinophilic airway inflammation.
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.
authors.affiliation: Department of Medicine, Division of Allergy and Clinical Immunology, Johns Hopkins University School of Medicine, Baltimore, Md.
authors.forename: Takumi
authors.initials: T
authors.lastname: Kiwamoto
authors.affiliation: Department of Medicine, Division of Allergy and Clinical Immunology, Johns Hopkins University School of Medicine, Baltimore, Md.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Brummet
authors.affiliation: Department of Medicine, Division of Allergy and Clinical Immunology, Johns Hopkins University School of Medicine, Baltimore, Md.
authors.forename: Fan
authors.initials: F
authors.lastname: Wu
authors.affiliation: Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Md.
authors.forename: Mary G
authors.initials: MG
authors.lastname: Motari
authors.affiliation: Department of Biochemistry, Emory University School of Medicine, Atlanta, Ga.
authors.forename: David F
authors.initials: DF
authors.lastname: Smith
authors.affiliation: Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Md.
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Schnaar
authors.affiliation: Department of Medicine, Division of Allergy and Clinical Immunology, Johns Hopkins University School of Medicine, Baltimore, Md.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Department of Medicine, Division of Allergy and Clinical Immunology, Johns Hopkins University School of Medicine, Baltimore, Md. Electronic address: bbochner@jhmi.edu.
authors.forename: Bruce S
authors.initials: BS
authors.lastname: Bochner
mesh_terms: D000818:Animals; D015214:Antigens, Differentiation, Myelomonocytic / Q000235:genetics / Q000378:metabolism*; D017209:Apoptosis / Q000235:genetics; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D016207:Cytokines / Q000276:immunology; D004804:Eosinophils / Q000276:immunology*; D007114:Immunization; D007074:Immunoglobulin G / Q000097:blood; D008168:Lung / Q000276:immunology / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010047:Ovalbumin / Q000276:immunology; D011014:Pneumonia / Q000235:genetics / Q000276:immunology*; D063265:Sialic Acid Binding Immunoglobulin-like Lectins; D012799:Sialyltransferases / Q000235:genetics*; D000094663:beta-Galactoside alpha-2,3-Sialyltransferase
chemical_list: D015214:Antigens, Differentiation, Myelomonocytic; D016207:Cytokines; D007074:Immunoglobulin G; D063265:Sialic Acid Binding Immunoglobulin-like Lectins; C443130:Siglecf protein, mouse; D010047:Ovalbumin; D012799:Sialyltransferases; D000094663:beta-Galactoside alpha-2,3-Sialyltransferase
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