Deficiency of a transcriptional regulator, inhibitor of differentiation 3, induces glomerulonephritis in apolipoprotein E-deficient mice: A model linking hyperlipidemia and renal disease

The clinical association between hyperlipidemia and renal disease is well established, yet hyperlipidemia as a cause for renal disease is rare. Apolipoprotein Edeficient (ApoE ^-/-) mice develop hyperlipidemia and are a model for atherosclerosis. Introducing deficiency of inhibitor of differentiation 3 (Id3) in ApoE ^-/- mice further exacerbates atherosclerosis. ID3 is a transcription regulator expressed in multiple cell types. Id3 ^-/- mice develop antibodies to self-antigens and salivary gland autoimmunity. This study was undertaken to investigate a link between hyperlipidemia, autoimmunity, and renal disease. ApoE ^-/-, Id3 ^-/-, and ApoE ^-/-Id3 ^-/- double-knockout (DKO) mice were studied at different ages for renal pathological features and function. Serum samples were analyzed for the presence of autoantibodies. At 16 weeks, DKO mice developed mesangioproliferative glomerulonephritis (GN), leading to severe proteinuria. GN was associated with glomerular deposition of lipids and immune complexes and with macrophage infiltration. DKO mice had high levels of circulating autoantibodies. Although ApoE ^-/- mice had glomerular lipid deposits and Id3 ^-/- mice had circulating autoantibodies, neither group of age-matched single-knockout mice developed GN. These data provide support for the hypothesis that induction of renal disease in hyperlipidemia is dictated by additional factors. Our study shows that some of these factors are regulated by ID3. Thus, ID3 is a novel risk factor linking cardiovascular and renal disease.