Project description:Lupus nephritis (LN) is characterized by immune-complex deposition in kidney glomeruli and has been classified according to histological features, but has not been characterized on a molecular level. This study aimed to characterize the relationship between histological and molecular phenotypes in LN. Renal compartmental mRNA expression was measured in 54 kidney biopsy specimens from patients with LN and correlated to histological phenotypes. The top identified transcripts were compared to a separate longitudinal cohort of 36 patients with paired kidney biopsies obtained at the time of flare and at follow up. Unsupervised clustering based on mRNA abundance resulted in clear separation by renal compartment, but did not demonstrate a relationship with LN class based on the International Society of Nephrology/Renal Pathology Society (ISN/RPS) classification, or the NIH activity and chronicity indices. A strong interferon gene signature was observed in both cohorts. FN1, SPP1, and LGALS-3 correlated with disease activity in both cohorts. The relationship between mRNA expression and ISN/RPS classification is modest. However, correlation of mRNA expression with individual histologic lesions identifies transcripts that change with resolution of disease flare, and provide insights into the molecular pathways potentially responsible for pathologic kidney lesions. Combining molecular and pathologic kidney biopsy phenotype may hold promise to better classify disease and identify actionable treatment targets.
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: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: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: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.
Project description:Genome-wide alternative splice analysis of RNA from lupus and its severe form lupus nephritis We aimed to explore the genome-wide peripheral blood transcriptome of lupus (SLE) and its severe form lupus nephritis (LN) cases compared to healthy subjects (HC) using high density Affymetrix Human Exon1.0.ST arrays. Analysis revealed 15 splice variants that are differentially expressed between SLE/HC and 99 variants between LN/HC (pâ¤0.05,SI>orâ¤0.5,Benjamin Hochberg-False discovery rate correction). Comparison between LN/SLE revealed 7 variants that are differentially expressed with pâ¤0.05,SI>0.5,Benjamin Hochberg-FDR correction. Pathway analysis of differentially spliced genes revealed 11 significant pathways in SLE and 12 in LN (p<0.05). Analysis of peripheral blood transcriptome revealed signature causative genes that are alternatively spliced, signifying their clinical relevance in the pathophysiology of disease. The extent of differential splicing was found to be higher in LN than in SLE, signifying the need for further in-depth research in the same domain. Present study is the first to reveal the significance of alternative variants in susceptibility to SLE and LN. We analyzed blood from 11 female subjects (5 lupus, 3 lupus nephritis and 3 healthy control) using the Affymetrix Human Exon 1.0 ST platform. Array data was processed by Alt Analyze and Genespring software. No techinical replicates were performed. One of the outiler sample (HC2) was excluded from further analysis.
Project description:GeneSet variation analysis was performed on microarrays to study the transcriptome of microdissected renal biopsies from lupus nephritis patients.
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.