Expression data from human with lupus nephritis (LN)

Nephritis (LN) is a serious manifestation of SLE. Therapeutic studies in mouse LN models do not always predict outcomes of human therapeutic trials, raising concerns about the human relevance of these models. In this study we used an unbiased transcriptional network approach to define similarities and differences between three lupus models and human LN. Affymetrix-based expression profiles were analyzed using Genomatix Bibliosphere software and transcriptional networks were compared using the Tool for Approximate LargE graph matching (TALE). The 20 network hubs (nodes) shared between all three models and human LN reflect key pathologic processes, namely immune cell infiltration/activation, macrophage/dendritic cell activation, endothelial cell activation/injury and tissue remodeling/fibrosis. Each model also shares unique features with human LN. Pathway analysis of the TALE nodes highlighted macrophage/DC activation as a cross-species shared feature. To distinguish which genes and activation pathways might derive from mononuclear phagocytes in the human kidneys the gene expression profile of isolated NZB/W renal mononuclear cells was compared with human LN kidney profiles. Network analysis of the shared signature highlighted NFkappaB1 and PPARgamma as major hubs in the tubulointerstitial and glomerular networks respectively. Key nodes in the renal macrophage inflammatory response form the basis for further mechanistic and therapeutic studies. We used microarrays to analyze the transcriptome of microdissected renal biopsies from patients with lupus nephritis (LN) RNA from glomeruli and tubulointerstitial compartments was extracted and processed for hybridization on Affymetrix microarrays.