IFN-gamma AU-rich element removal promotes chronic IFN-gamma expression and autoimmunity in mice

J Autoimmun. 2014 Sep:53:33-45. doi: 10.1016/j.jaut.2014.02.003. Epub 2014 Feb 28.

Abstract

We generated a mouse model with a 162 nt AU-rich element (ARE) region deletion in the 3' untranslated region (3'UTR) of the interferon-gamma (IFN-γ) gene that results in chronic circulating serum IFN-γ levels. Mice homozygous for the ARE deletion (ARE-Del) (-/-) present both serologic and cellular abnormalities typical of patients with systemic lupus erythematosus (SLE). ARE-Del(-/-) mice display increased numbers of pDCs in bone marrow and spleen. Addition of IFN-γ to Flt3-ligand (Flt3L) treated in vitro bone marrow cultures results in a 2-fold increase in pDCs with concurrent increases in IRF8 expression. Marginal zone B (MZB) cells and marginal zone macrophages (MZMs) are absent in ARE-Del(-/-) mice. ARE-Del(+/-) mice retain both MZB cells and MZMs and develop no or mild autoimmunity. However, low dose clodronate treatment in ARE-Del(+/-) mice specifically eliminates MZMs and promotes anti-DNA antibody development and glomerulonephritis. Our findings demonstrate the consequences of a chronic IFN-γ milieu on B220(+) cell types and in particular the impact of MZB cell loss on MZM function in autoimmunity. Furthermore, similarities between disease states in ARE-Del(-/-) mice and SLE patients suggest that IFN-γ may not only be a product of SLE but may be critical for disease onset and progression.

Keywords: Autoimmunity; Glomerulonephritis; Interferon gamma; Systemic lupus erythematosus.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • AU Rich Elements / genetics*
  • Animals
  • Antibodies, Antinuclear / immunology
  • B-Lymphocytes / immunology
  • B-Lymphocytes / pathology
  • Base Sequence*
  • Gene Expression Regulation / genetics
  • Gene Expression Regulation / immunology
  • Humans
  • Interferon Regulatory Factors / genetics
  • Interferon Regulatory Factors / immunology
  • Interferon-gamma* / genetics
  • Interferon-gamma* / immunology
  • Lupus Nephritis / genetics
  • Lupus Nephritis / immunology*
  • Macrophages / immunology
  • Macrophages / pathology
  • Membrane Proteins / genetics
  • Membrane Proteins / immunology
  • Mice
  • Mice, Knockout
  • Sequence Deletion*

Substances

  • Antibodies, Antinuclear
  • Interferon Regulatory Factors
  • Membrane Proteins
  • flt3 ligand protein
  • interferon regulatory factor-8
  • Interferon-gamma