Circulating CSF-1 Promotes Monocyte and Macrophage Phenotypes that Enhance Lupus Nephritis
Macrophages mediate kidney disease and are prominent in a mouse model (MRL- Fas lpr ) of lupus nephritis. Colony stimulating factor-1 (CSF-1) is the primary growth factor for macrophages, and CSF-1 deficiency protects MRL- Fas lpr mice from kidney disease and systemic illness. Whether this renoprotection derives from a reduction of macrophages and whether systemic CSF-1, as opposed to intrarenal CSF-1, promotes macrophage-dependent lupus nephritis remain unclear. Here, we found that increasing systemic CSF-1 hastened the onset of lupus nephritis in MRL- Fas lpr mice. Using mutant MRL- Fas lpr strains that express high, moderate, or no systemic CSF-1, we detected a much higher tempo of kidne…
Targeting transcription factor Stat4 uncovers a role for interleukin-18 in the pathogenesis of severe lupus nephritis in mice
Polymorphisms in the transcription factor Stat4 gene have been implicated as risk factors for systemic lupus erythematosus. Although some polymorphisms have a strong association with autoantibodies and nephritis, their impact on pathophysiology is still unknown. To explore this further we used signal transducers and activators of transcription 4 (Stat4) knockout MRL/MpJ-Fas(lpr)/Fas(lpr) (MRL-Fas(lpr)) mice and found that they did not differ in survival or renal function from Stat4-intact MRL-Fas(lpr) mice. Circulating interleukin (IL)-18 levels, however, were elevated in Stat4-deficient compared to Stat4-intact mice, suggesting that this interleukin might contribute to the progression of l…