Project description:Proliferative glomerulonephritis is a severe condition often leading to kidney failure. There is a significant lack of effective treatment for these disorders. Here, following the identification of a somatic PIK3CA gain-of-function mutation in podocytes of a patient, we demonstrate using multiple genetically engineered mouse models, single-cell RNA sequencing and spatial transcriptomics the crucial role played by this pathway for proliferative glomerulonephritis development by promoting podocyte proliferation, dedifferentiation and inflammation. Additionally, we show that alpelisib, a PI3Kα inhibitor, improves glomerular lesions and kidney function in different mouse models of proliferative glomerulonephritis and lupus nephritis by targeting podocytes. Surprisingly, we determined that pharmacological inhibition of PI3Kα affects B and T lymphocyte population in lupus nephritis mouse models with decrease in the production of proinflammatory cytokines, autoantibodies and glomerular complement deposition, which are all characteristic features of PI3K delta (PI3Kδ) inhibition, the primary PI3K isoform expressed in lymphocytes. Importantly, PI3Kα inhibition does not impact lymphocyte function under normal conditions. These findings were then confirmed in human lymphocytes isolated from patients with active lupus nephritis. In conclusion, we demonstrate the major role played by PI3Kα in proliferative glomerulonephritis and show that in this condition, alpelisib acts on both podocytes and the immune system.
Project description:This SuperSeries is composed of the following subset Series: GSE32583: Expression data from lupus NZB/W, NZM2410, NZW/BXSB mouse kidneys prenephritic and nephritic. GSE32591: Expression data from human with lupus nephritis (LN) Refer to individual Series
Project description:Membranous lupus nephritis is a frequent cause of nephrotic syndrome in patients with systemic lupus erythematosus. Unlike phospholipase A2 receptor or thrombospondin type 1 domain containing 7A-associated membranous nephropathy, where known antibodies can be detected within sera by indirect immunofluorescence and/or enzyme-linked immunosorbent assay, it is not possible to monitor disease activity in membranous lupus nephritis where the target autoantigens are mostly unknown. Determination of the target autoantigen has diagnostic significance, informs prognosis, and allows for non-invasive monitoring of disease activity in serum. We utilized mass spectrometry for antigen discovery of laser capture microdissected glomeruli from formalin-fixed paraffin embedded tissue and tissue IgG immunoprecipitation studies from frozen kidney biopsy tissue. We identified neural cell adhesion molecule 1 (NCAM1) to be a target antigen in membranous lupus nephritis and within rare cases of primary membranous nephropathy. The prevalence of NCAM1-associated membranous neuropathy was 5.7% of cases of membranous lupus nephritis. NCAM1 co-localizes with IgG within glomerular immune deposits. Additionally, serum from NCAM1 patients showed reactivity to NCAM1 recombinant protein. The presence of anti-NCAM1 antibodies in sera could allow for non-invasive monitoring of the disease. We propose that NCAM1 is a target autoantigen in a subset of patients with membranous lupus nephritis. Future studies are needed to determine whether anti-NCAM1 antibody levels correlate with disease activity or response to therapy.
Project description:NZB/WF1 female mice spontaneously develop autoimmune lupus nephritis. Expression profiling of kidney tissue from (a) 12 week NZB/W F1 female mice defined as asymptomatic for lupus nephritis, (b) 36 and 42 week NZB/W F1 female mice defined as diseased/symptomatic for lupus nephritis and (c) 36 and 42 week NZB/W F1 female mice that are diseased/symptomatic for lupus nephritis and treated with Sirolimus was carried out. The goal of the study was to identify genes associated with lupus nephritis and modulated by Sirolimus, an inhibitor of mTOR. In addition, lupus nephritis genes resistant to Sirolimus therapy were also identfied This series of samples comprises of kidney tissue from (a) 12 week old NZB/W F1 female mice defined as asymptomatic for lupus nephritis (N=4), (b) 36 (N=3) and 42 week (N=3) old NZB/W F1 female mice defined as diseased/symptomatic for lupus nephritis and (c) 36 (N=3)and 42 (N=3) week old NZB/W F1 female mice that are asymptomatic for lupus nephritis on treatment with Sirolimus
Project description: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.
Project description:MicroRNAs (miRNA) have emerged as an important new class of modulators of gene expression. In this sudy we investigated miRNA that are differentially expressed in lupus nephritis. Microarray technology was used to investigate differentially expressed miRNA in PBMCs and EBV-transformed cell lines obtained from lupus nephritis patients and controls. TaqMan-based stem-loop real-time PCR was used for validation. Microarray analysis of miRNA expressed in African Americans (AA) derived lupus nephritis samples revealed 29 differentially expressed miRNA, of 850 tested. Microarray analysis of miRNA expressed in European American (EA) derived lupus nephritis samples revealed 50 differentially expressed miRNA, of 850 tested.
Project description:NZB/WF1 female mice spontaneously develop autoimmune lupus nephritis. Expression profiling of kidney tissue from (a) 12 week NZB/W F1 female mice defined as asymptomatic for lupus nephritis, (b) 36 and 42 week NZB/W F1 female mice defined as diseased/symptomatic for lupus nephritis and (c) 36 and 42 week NZB/W F1 female mice that are diseased/symptomatic for lupus nephritis and treated with Sirolimus was carried out. The goal of the study was to identify genes associated with lupus nephritis and modulated by Sirolimus, an inhibitor of mTOR. In addition, lupus nephritis genes resistant to Sirolimus therapy were also identfied
Project description:Lupus nephritis with pronounced signs of chronic kidney disease leads to significant changes in the heart. It is not yet clear whether these changes are caused by the chronic kidney disease or by the autoimmune disease. It is also unclear which factors are responsible for the cardiovascular changes. Therefore, the gene expression of mice with lupus nephritis (NZB_W) will be compared with healthy controls (NZW).
Project description:Lupus nephritis is a serious complication of systemic lupus erythematosus, mediated by IgG immune complex (IC) deposition in kidneys, with limited treatment options. Kidney macrophages are critical tissue sentinels that express IgG-binding Fcγ receptors (FcγRs), with previous studies identifying prenatally seeded resident macrophages as major IC responders. Using single-cell transcriptomic and spatial analyses in murine and human lupus nephritis, we sought to understand macrophage heterogeneity and subset-specific contributions in disease. In lupus nephritis, the cell fate trajectories of tissue-resident (TrMac) and monocyte-derived (MoMac) kidney macrophages were perturbed, with disease-associated transcriptional states indicating distinct pathogenic roles for TrMac and MoMac subsets. Lupus nephritis–associated MoMac subsets showed marked induction of FcγR response genes, avidly internalized circulating ICs, and presented IC-opsonized antigen. In contrast, lupus nephritis-associated TrMac subsets demonstrated limited IC uptake, but expressed monocyte chemoattractants, and their depletion attenuated monocyte recruitment to the kidney. TrMacs also produced B cell tissue niche factors, suggesting a role in supporting autoantibody-producing lymphoid aggregates. Extensive similarities were observed with human kidney macrophages, revealing cross-species transcriptional disruption in lupus nephritis. Overall, our study suggests a division of labor in the kidney macrophage response in lupus nephritis, with treatment implications — TrMacs orchestrate leukocyte recruitment while MoMacs take up and present IC antigen.