Interleukin-17 promotes the production of underglycosylated IgA1 in DAKIKI cells

Ren Fail. 2018 Nov;40(1):60-67. doi: 10.1080/0886022X.2017.1419972.

Abstract

Background: Interleukin 17 (IL-17) plays an important role in the pathogenesis of autoimmune diseases and might be associated with IgA nephropathy (IgAN). This study aimed to investigate the effect of IL-17 on autoimmune pathogenesis in IgA nephropathy.

Methods: DAKIKI cells were cultured and stimulated with IL-17 to perform dose-dependent and time-dependent experiments. Cell proliferation was examined by cell counting and the Cell Counting Kit-8 (CCK-8) assay. The IgA concentration and the degree of galactosylation in the supernatant were tested using ELISA and a helix aspersa (HAA) lectin binding assay, respectively. To study the mechanism of O-glycosylation, cells were stimulated with IL-17, lipopolysaccharide (LPS) or 5-azacytidine (5-AZA) + IL-17 for 48 h, and the levels of C1GALT1 and its molecular chaperone Cosmc were measured by western blot and real-time PCR.

Results: The cell counting and CCK-8 results suggested that B lymphocyte proliferation increased significantly with increased IL-17 concentration. IL-17 affected the quantity of IgA1 and its glycosylation status. HAA revealed that IL-17 promoted IgA1 underglycosylation. Mechanistically, the expression of C1GALT1 and Cosmc was significantly lower in cells stimulated by IL-17 or LPS than in the 5-AZA + IL-17 or the control group.

Conclusions: Our results suggested that IL-17 stimulates B lymphocyte to promote B-cell proliferation, which leads to increased IgA1 production in vitro accompanied by underglycosylation of IgA1. The molecular mechanism for the IgA1 underglycosylation induced by IL-17 was similar to that of LPS; however, 5-AZA inhibited IgA1 underglycosylation. IL-17 might participate in IgAN pathogenesis by influencing the production and glycosylation of IgA1 in B-cells.

Keywords: C1GALT1; Cosmc; IgA nephropathy; IgA1; Interleukin 17; underglycosylation.

MeSH terms

  • Azacitidine / pharmacology
  • B-Lymphocytes / immunology
  • B-Lymphocytes / physiology*
  • Cell Count
  • Cell Line, Tumor
  • Cell Proliferation
  • Enzyme-Linked Immunosorbent Assay
  • Galactosyltransferases / metabolism*
  • Glomerulonephritis, IGA / immunology*
  • Glycosylation
  • Humans
  • Immunoglobulin A / immunology
  • Immunoglobulin A / metabolism*
  • Interleukin-17 / immunology
  • Interleukin-17 / metabolism*
  • Lipopolysaccharides / pharmacology
  • Molecular Chaperones / metabolism
  • Up-Regulation

Substances

  • C1GALT1C1 protein, human
  • Immunoglobulin A
  • Interleukin-17
  • Lipopolysaccharides
  • Molecular Chaperones
  • C1GALT1 protein, human
  • Galactosyltransferases
  • Azacitidine

Grants and funding

This work was supported by grants from the National Natural Science Foundation of China [81170667], the Youth Science and Technology Support Program of Sichuan Province [2011JDT0014], funding from Sichuan Medical University and funding from the Affiliated Hospital of Sichuan Medical University.