Critical Role of Kupffer Cell CD89 Expression in Experimental IgA Nephropathy

PLoS One. 2016 Jul 20;11(7):e0159426. doi: 10.1371/journal.pone.0159426. eCollection 2016.

Abstract

Although IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide, its etiology remains only partly understood. It is clear that the pathogenesis of IgAN involves the formation of macromolecular IgA1 complexes and increased levels of serum IgA1 and IgA1-immune complexes(IC), due to defective IgA1 clearance. Previous studies suggest that the blood and tissue myeloid cell-expressed IgA Fc receptor (FcαR/CD89) mediates IgA-IC clearance and its dysfunction, via decreased activity or excessive levels of soluble FcαR/sCD89 induces IgAN. Such a mechanism requires robust stimulation of IgAN levels via forced expression of CD89. In the absence of unequivocal evidence supporting such a mechanism to date, we attempted to test the extent of CD89-evoked IgAN by generating a transgenic mouse strain expressing human CD89 under the control of murine CD14 promotor. No deposition of IgA-CD89 complexes or glomerulonephritis was detected, however. Further studies showed that elimination of murine IgA was mediated by Kupffer cells. In patients, however, CD89/IgA complexes were detected, and injection of patient IgA induced IgAN-like features in CD89 Tg mice. In transgenic mice, IgAN pathogenesis involves impaired clearance of abnormal IgA via CD89, primarily by the Kupffer cells. Conditional IgAN progression in CD89 transgenic mice thus reveals important aspects of IgAN pathogenesis.

MeSH terms

  • Animals
  • Antigens, CD / blood*
  • Antigens, CD / immunology
  • Disease Models, Animal
  • Female
  • Gene Expression Regulation
  • Glomerulonephritis, IGA / blood
  • Glomerulonephritis, IGA / genetics*
  • Glomerulonephritis, IGA / physiopathology
  • Humans
  • Immunoglobulin A / blood*
  • Immunoglobulin A / immunology
  • Kupffer Cells / metabolism
  • Kupffer Cells / pathology
  • Male
  • Mice
  • Mice, Transgenic
  • Receptors, Fc / blood*
  • Receptors, Fc / immunology

Substances

  • Antigens, CD
  • Fc(alpha) receptor
  • Immunoglobulin A
  • Receptors, Fc

Grant support

This work was supported by the National Basic Research Program of China (973 Program 2015CB553706), the National Natural Science Foundation of China (NSFC 31470896 and NSFC 81402399), and Shanghai Science & Technology Pillar Program 12431901000).