title: Anti-inflammatory IgG production requires functional P1 promoter in β-galactoside α2,6-sialyltransferase 1 (ST6Gal-1) gene.
abstract: The anti-inflammatory properties associated with intravenous immunoglobulin therapy require the sialic acid modification of the N-glycan of the Fc domain of IgG. Sialylation of the Fc fragment is mediated by β-galactoside α2,6-sialyltransferase 1 (ST6Gal-1), acting on the Gal(β4)GlcNAc terminal structure of the biantennary N-glycans on the Fc domain. However, little is known regarding the in vivo regulation of Fc sialylation and its role in the progression of inflammatory processes. Here, we report that decreased Fc sialylation of circulatory IgG accompanies the acute phase response elicited by turpentine exposure or upon acute exposure to either nontypeable Haemophilus influenzae or ovalbumin. However, Fc sialylation was increased 3-fold from the base line upon transition to chronic inflammation by repeated exposure to challenge. The P1 promoter of the ST6Gal-1 gene is critical for Fc sialylation, but P1 does not drive ST6Gal-1 expression in B cells. The Siat1ΔP1 mouse, with a dysfunctional P1 promoter, was unable to produce sialylated Fc in the systemic circulation, despite the presence of Gal(β4)GlcNAc termini on the Fc glycans. The major contribution of P1 action is to synthesize ST6Gal-1 enzymes that are deposited into the systemic circulation. The data strongly indicate that this pool of extracellular ST6Gal-1 in the blood impacts the sialylation of IgG Fc and that defective Fc sialylation is likely a major contributing mechanism for the proinflammatory tendencies previously noted in Siat1ΔP1 animals.
authors.affiliation: Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, New York 14263, USA.
authors.forename: Mark B
authors.initials: MB
authors.lastname: Jones
authors.forename: Mehrab
authors.initials: M
authors.lastname: Nasirikenari
authors.forename: Amit A
authors.initials: AA
authors.lastname: Lugade
authors.forename: Yasmin
authors.initials: Y
authors.lastname: Thanavala
authors.forename: Joseph T Y
authors.initials: JT
authors.lastname: Lau
mesh_terms: D000210:Acute-Phase Reaction / Q000139:chemically induced / Q000276:immunology / Q000378:metabolism; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000276:immunology / Q000378:metabolism*; D015153:Blotting, Western; D004195:Disease Models, Animal; D015971:Gene Expression Regulation, Enzymologic; D006192:Haemophilus Infections / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D006193:Haemophilus influenzae / Q000276:immunology; D007141:Immunoglobulin Fc Fragments / Q000276:immunology / Q000378:metabolism; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019158:N-Acetylneuraminic Acid / Q000378:metabolism; D010047:Ovalbumin / Q000276:immunology; D011014:Pneumonia / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D011134:Polysaccharides / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012799:Sialyltransferases / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014425:Turpentine; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase
chemical_list: D000893:Anti-Inflammatory Agents; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D011134:Polysaccharides; D010047:Ovalbumin; D012799:Sialyltransferases; D019158:N-Acetylneuraminic Acid; D014425:Turpentine; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase