We integrated three transplant rejection microarray studies examining gene expression in samples from pediatric renal, adult renal, and adult heart transplants. We performed one study ourselves and retrieved two others from the NCBI Gene Expression Omnibus (GEO)(GSE4470 and GSE1563). We identified 45 genes that were upregulated in common in acute rejection. Half were involved in one immune-related pathway. Among ten proteins we tested by serum ELISA, three successfully distinguished acute rejection from stable transplants. These were CXCL9, PECAM1, and CD44, with areas under the receiver operating characteristic curves of 0.844, 0.802, and 0.738, respectively. Immunohistochemistry showed that the PECAM1 protein was increased in acute rejection in renal, liver and heart transplants versus normal tissues. Our results show that integrating publicly-available gene expression data sets is a fast, powerful, and cost-effective way to identify serum-detectable diagnostic biomarkers.
Integrative urinary peptidomics in renal transplantation identifies biomarkers for acute rejection.
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Molecular heterogeneity in acute renal allograft rejection identified by DNA microarray profiling.
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View Samples-catenin signaling is required for hair follicle development, but it is unknown whether it is sufficient to activate expression of hair follicle genes in embryonic skin. To address this we profiled gene expression in dermis from E15.5 KRT14-Cre Ctnnb1(Ex3)fl/+ embryos carrying an activating mutation in epithelial beta-catenin, and control littermate embryos.
Molecular heterogeneity in acute renal allograft rejection identified by DNA microarray profiling.
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View Samples-catenin signaling is required for hair follicle development, but it is unknown whether it is sufficient to activate expression of hair follicle genes in embryonic skin. To address this we profiled gene expression in skin dissected from E14.5 KRT14-Cre Ctnnb1(Ex3)fl/+ embryos carrying an activating mutation in epithelial beta-catenin, and control littermate embryos.
Molecular heterogeneity in acute renal allograft rejection identified by DNA microarray profiling.
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View Samples-catenin signaling is required for hair follicle development, but it is unknown whether it is sufficient to activate expression of hair follicle genes in embryonic skin. To address this we profiled gene expression in epidermis from E15.5 KRT14-Cre Ctnnb1(Ex3)fl/+ embryos carrying an activating mutation in epithelial beta-catenin, and control littermate embryos.
Molecular heterogeneity in acute renal allograft rejection identified by DNA microarray profiling.
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View SamplesCONTEXT Slowly progressive chronic tubulo-interstitial damage jeopardizes long-term renal allograft survival. Both immune and non-immune mechanisms are thought to contribute, but the most promising targets for timely intervention have not been identified. OBJECTIVE In the current study we seek to determine the driving force behind progressive histological damage of renal allografts, without the interference of donor pathology, delayed graft function and acute graft rejection. DESIGN We used microarrays to examine whole genome expression profiles in renal allograft protocol biopsies, and analyzed the correlation between gene expression and the histological appearance over time. The gene expression profiles in these protocol biopsies were then compared with gene expression of biopsies with acute T-cell mediated rejection. PATIENTS Human renal allograft biopsies (N=120) were included: 96 rejection-free protocol biopsies and 24 biopsies with T-cell mediated acute rejection. RESULTS In this highly cross-validated study, we demonstrate the significant association of established, ongoing and future chronic histological damage with regulation of adaptive immune gene expression (T-cell and B-cell transcript sets) and innate immune response gene expression (dendritic cell, NK-cell, mast cell and granulocyte transcripts). We demonstrate the ability of gene expression analysis to perform as a quantitative marker for ongoing inflammation with a wide dynamic range: from subtle subhistological inflammation prior to development of chronic damage, over moderate subclinical inflammation associated with chronic histological damage, to marked inflammation of Banff-grade acute T-cell mediated rejection. CONCLUSION Progressive chronic histological damage after kidney transplantation is associated with significant regulation of both innate and adaptive immune responses, months before the histological lesions appear. This study therefore corroborates the hypothesis that quantitative inflammation below the diagnostic threshold of classic T-cell or antibody-mediated rejection is associated with early subclinical stages of progressive renal allograft damage.
Progressive histological damage in renal allografts is associated with expression of innate and adaptive immunity genes.
Specimen part, Time
View SamplesPolyoma virus nephropathy (PVAN) is a common cause of kidney allograft dysfunction and loss. Microscopic descriptions of PVAN are very similar to T-cell mediated rejection (TCMR) and have unclear underlying molecular mechanisms. To identify PVAN-specific gene expression, we analyzed 162 kidney biopsies with and without PVAN for global gene expression. Unsupervised hierarchical clustering analysis of all 162 biopsies revealed high similarity between PVAN and TCMR gene expression. Increasing the stringency for the specificity (p <0.001 and >2-fold expression) between PVAN and TCMR, 158 and 252 unique PVAN and TCMR injury-specific probesets were observed, respectively. While TCMR-specific probeset were overwhelmingly involved in immune response costimulation (CTLA4, CD28, CD86) and TCR (NFATC2, LCP2) signaling, PVAN-specific probesets were mainly related to viral replication process (IFITM1, LTF, NOSIP, RARRES3), RNA polymerase assembly (POLR2l, TAF10, RPS15) and pathogen recognition receptors (C1QA, C3, CFD). A principal component analysis using these genes further confirmed the most optimal separation between the 3 different clinical phenotypes. Validation of 4 PVAN-specific probesets (RPS15, CFD, LTF, and NOSIP) by QPCR and further confirmation by IHC of 2 PVAN-specific proteins with anti-viral function (LTF and IFITM1) was done, showing significantly higher expression within interstitial cellular infiltrates and in tubuli in PVAN specimens as compared to TCMR and NL kidney biopsies. In conclusion, even though PVAN and TCMR kidney allografts share great similarities on gene perturbation, particular PVAN-specific transcripts were identified with well-known anti-viral properties that provide tools for discerning PVAN and AR as well as attractive targets for rational drug design.
Intragraft Antiviral-Specific Gene Expression as a Distinctive Transcriptional Signature for Studies in Polyomavirus-Associated Nephropathy.
Specimen part, Disease
View SamplesBiologic markers of immune tolerance may facilitate tailoring of immune suppression duration after allogeneic hematopoietic cell transplantation (HCT). In a cross-sectional study, peripheral blood samples were obtained from tolerant (n=15, median 38.5 months post-HCT) and non-tolerant (n=17, median 39.5 post-HCT) HCT recipients and healthy control subjects (n=10) for analysis of immune cell subsets and differential gene expression. There were no significant differences in immune subsets across groups. We identified 281 probe sets unique to the tolerant (TOL) group and 122 for non-tolerant (non-TOL). These were enriched for process networks including NK cell cytotoxicity, antigen presentation, lymphocyte proliferation, and cell cycle and apoptosis. Differential gene expression was enriched for CD56, CD66, and CD14 human lineage-specific gene expression. Differential expression of 20 probe sets between groups was sufficient to develop a classifier with > 90% accuracy, correctly classifying 14/15 TOL cases and 15/17 non-TOL cases. These data suggest that differential gene expression can be utilized to accurately classify tolerant patients following HCT. Prospective investigation of immune tolerance biologic markers is warranted.
Tolerance associated gene expression following allogeneic hematopoietic cell transplantation.
Specimen part, Subject
View SamplesThe biopsy samples obtained at implantation segregated in 2 distinct groups according to donor origin, with a cluster of 319 unique identified genes higher expressed in DD compared to LD kidneys, and 329 genes lower expressed (false discovery rate <5%). Using pathway analysis software a significant local renal overrepresentation of complement genes in DD implantation biopsies was identified. Complement gene expression in DD kidneys related both to donor death and cold ischemia duration, and was associated with a slower onset of renal allograft function. In post-transplantation protocol biopsies, there was a continued overexpression of complement genes, regardless of donor source. The local renal complement gene expression variability in post-transplantation biopsies correlated with renal graft function.
Expression of complement components differs between kidney allografts from living and deceased donors.
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View SamplesTissues are often made up of multiple cell-types. Blood, for example, contains many different cell-types, each with its own functional attributes and molecular signature. In humans, because of its accessibility and immune functionality, blood cells have been used as a source for RNA-based biomarkers for many diseases. Yet, the proportions of any given cell-type in the blood can vary markedly, even between normal individuals. This results in a significant loss of sensitivity in gene expression studies of blood cells and great difficulty in identifying the cellular source of any perturbations. Ideally, one would like to perform differential expression analysis between patient groups for each of the cell-types within a tissue but this is impractical and prohibitively expensive.
Cell type-specific gene expression differences in complex tissues.
Specimen part
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