MΦ of mice from the major inbred models of systemic lupus erythematosus (SLE) have an identical defect affecting the activity of the cytoskeletal regulator and G-protein Rho. This abnormality is triggered by apo cells. Strikingly, SLE-prone MΦ show normal Rho activity when cultured in the absence of apo cells. We used gene arrays to identify adhesion-related gene products that are abnormally expressed by MΦ from prediseased 4–6-week-old SLE-prone MRL mice in the presence of serum lipids mimicking apo cells (SL-Apo). MΦ of MRL mice differentially expressed 42 adhesion-related genes in the presence of SL-Apo. Of these, 32 were expressed normally in the absence of SL-Apo. As adhesive interactions play a major role in lymphocyte activation, the detected apo cell-dependent abnormality could predispose to the development of autoimmunity. Indeed, several recent genetic studies support a role for adhesion-related genes in the pathogenesis of chronic autoimmunity.
Keywords: Cytoskeleton, SLE, rodent, autoimmunity, gene array