» Articles » PMID: 39095059

O-glycosylation of IgA1 and the Pathogenesis of an Autoimmune Disease IgA Nephropathy

Overview
Journal Glycobiology
Date 2024 Aug 2
PMID 39095059
Authors
Affiliations
Soon will be listed here.
Abstract

IgA nephropathy is a kidney disease characterized by deposition of immune complexes containing abnormally O-glycosylated IgA1 in the glomeruli. Specifically, some O-glycans are missing galactose that is normally β1,3-linked to N-acetylgalactosamine of the core 1 glycans. These galactose-deficient IgA1 glycoforms are produced by IgA1-secreting cells due to a dysregulated expression and activity of several glycosyltransferases. Galactose-deficient IgA1 in the circulation of patients with IgA nephropathy is bound by IgG autoantibodies and the resultant immune complexes can contain additional proteins, such as complement C3. These complexes, if not removed from the circulation, can enter the glomerular mesangium, activate the resident mesangial cells, and induce glomerular injury. In this review, we briefly summarize clinical and pathological features of IgA nephropathy, review normal and aberrant IgA1 O-glycosylation pathways, and discuss the origins and potential significance of natural anti-glycan antibodies, namely those recognizing N-acetylgalactosamine. We also discuss the features of autoantibodies specific for galactose-deficient IgA1 and the characteristics of pathogenic immune complexes containing IgA1 and IgG. In IgA nephropathy, kidneys are injured by IgA1-containing immune complexes as innocent bystanders. Most patients with IgA nephropathy progress to kidney failure and require dialysis or transplantation. Moreover, most patients after transplantation experience a recurrent disease. Thus, a better understanding of the pathogenetic mechanisms is needed to develop new disease-specific treatments.

References
1.
Novak J, Vu H, Novak L, Julian B, Mestecky J, Tomana M . Interactions of human mesangial cells with IgA and IgA-containing immune complexes. Kidney Int. 2002; 62(2):465-75. DOI: 10.1046/j.1523-1755.2002.00477.x. View

2.
Gerken T, Jamison O, Perrine C, Collette J, Moinova H, Ravi L . Emerging paradigms for the initiation of mucin-type protein O-glycosylation by the polypeptide GalNAc transferase family of glycosyltransferases. J Biol Chem. 2011; 286(16):14493-507. PMC: 3077648. DOI: 10.1074/jbc.M111.218701. View

3.
Fiskesund R, Steen J, Amara K, Murray F, Szwajda A, Liu A . Naturally occurring human phosphorylcholine antibodies are predominantly products of affinity-matured B cells in the adult. J Immunol. 2014; 192(10):4551-9. DOI: 10.4049/jimmunol.1303035. View

4.
Green C . The ABO, Lewis and related blood group antigens; a review of structure and biosynthesis. FEMS Microbiol Immunol. 1989; 1(6-7):321-30. DOI: 10.1111/j.1574-6968.1989.tb02417.x. View

5.
Storr S, Royle L, Chapman C, Abd Hamid U, Robertson J, Murray A . The O-linked glycosylation of secretory/shed MUC1 from an advanced breast cancer patient's serum. Glycobiology. 2008; 18(6):456-62. DOI: 10.1093/glycob/cwn022. View