BACKGROUND: In IgA nephropathy (IgAN), circulating IgA1 molecules display an abnormal pattern of O-glycosylation. This abnormality may potentially contribute to mesangial IgA1 deposition, but this is unproven because the O-glycosylation of mesangial IgA1 has not been analyzed. METHODS: IgA1 was eluted from glomeruli isolated from the kidneys of three IgAN patients obtained after nephrectomy or at postmortem. Serum from these patients, other patients with IgAN, and controls was subjected to the same treatment as the glomerular eluates. The O-glycosylation of eluted and serum IgA1 was measured by lectin binding using an enzyme-linked immunosorbent assay-based system. RESULTS: In all three cases, the lectin binding of IgA1 eluted from the glomeruli of IgAN patients was markedly higher than that of the serum IgA1 of the same individual, and also all but one of a series of serum IgA1 samples from other patients and controls. CONCLUSIONS: The higher lectin binding of glomerular compared with serum IgA1 suggests that O-glycosylated IgA1 molecules abnormally and selectively deposit in the kidney. These results provide the first evidence that mesangial IgA1 is abnormally O-glycosylated, and support a direct role for abnormal IgA1 O-glycosylation in the mechanism of mesangial IgA deposition in IgAN.
BACKGROUND: In IgAnephropathy (IgAN), circulating IgA1 molecules display an abnormal pattern of O-glycosylation. This abnormality may potentially contribute to mesangial IgA1 deposition, but this is unproven because the O-glycosylation of mesangial IgA1 has not been analyzed. METHODS:IgA1 was eluted from glomeruli isolated from the kidneys of three IgANpatients obtained after nephrectomy or at postmortem. Serum from these patients, other patients with IgAN, and controls was subjected to the same treatment as the glomerular eluates. The O-glycosylation of eluted and serum IgA1 was measured by lectin binding using an enzyme-linked immunosorbent assay-based system. RESULTS: In all three cases, the lectin binding of IgA1 eluted from the glomeruli of IgANpatients was markedly higher than that of the serum IgA1 of the same individual, and also all but one of a series of serum IgA1 samples from other patients and controls. CONCLUSIONS: The higher lectin binding of glomerular compared with serum IgA1 suggests that O-glycosylated IgA1 molecules abnormally and selectively deposit in the kidney. These results provide the first evidence that mesangial IgA1 is abnormally O-glycosylated, and support a direct role for abnormal IgA1 O-glycosylation in the mechanism of mesangial IgA deposition in IgAN.
Authors: Michelle M Gomes; Hitoshi Suzuki; Monica T Brooks; Milan Tomana; Zina Moldoveanu; Jiri Mestecky; Bruce A Julian; Jan Novak; Andrew B Herr Journal: Biochemistry Date: 2010-07-13 Impact factor: 3.162
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Authors: Ali G Gharavi; Zina Moldoveanu; Robert J Wyatt; Catherine V Barker; Susan Y Woodford; Richard P Lifton; Jiri Mestecky; Jan Novak; Bruce A Julian Journal: J Am Soc Nephrol Date: 2008-02-13 Impact factor: 10.121
Authors: Francois Berthoux; Hitoshi Suzuki; Lise Thibaudin; Hiroyuki Yanagawa; Nicolas Maillard; Christophe Mariat; Yasuhiko Tomino; Bruce A Julian; Jan Novak Journal: J Am Soc Nephrol Date: 2012-08-16 Impact factor: 10.121