Unknown,Transcriptomics,Genomics,Proteomics

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A common rejection module for acute rejection in multiple organs identifies novel therapeutics.

ABSTRACT: Using meta-analysis of eight independent transplant datasets (236 graft biopsy samples) from four organs, we identified a common rejection module (CRM) consisting of 11 genes that were significantly overexpressed in acute rejection (AR) across all transplanted organs. The CRM genes could diagnose AR with high specificity and sensitivity in three additional independent cohorts (794 samples). In another two independent cohorts (151 renal transplant biopsies), the CRM genes correlated with the extent of graft injury and predicted future injury to a graft using protocol biopsies. Inferred drug mechanisms from the literature suggested that two FDA-approved drugs (atorvastatin and dasatinib), approved for non-transplant indications, could regulate specific CRM genes and reduce the number of graft infiltrating cells during acute rejection. We treated mice with HLA-mismatched murine cardiac transplant with atorvastatin and dasatinib and showed reduction of the CRM genes, significant reduction of graft infiltrating cells, and extended graft survival. We further validated the beneficial effect of atorvastatina on graft survival by retrospective analysis of electronic medical records of a single-center cohort of 2,515 renal transplant patients. In conclusion, we identified a CRM in transplantation that provides new opportunities for diagnosis, drug repositioning and rational drug design. The eight transplant data sets used for discovery include GSE4315, GSE2596, GSE4470, GSE9377, GSE1563, GSE9493, GSE13440, GSE6095. The two additional independent cohorts of 151 transplant biopsies are GSE25902 and GSE1563. Not all samples from all studies were used. Only the samples marked as either AR or STA in each data set were used for analysis. The 101 samples in this study were used as case-control experiment between acute rejection (AR) and stable (STA) in renal transplant. The samples in this series are one of the three independent validation cohorts. The other two cohorts are described in GSE21374 and GSE36059

ORGANISM(S): Homo sapiens

SUBMITTER: Purvesh Khatri

PROVIDER: E-GEOD-50058 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:This study corresponds to a re-analysis and meta-analysis of the five transcriptomic studies related to spontaneous tolerance to renal allograft in human. It examines the transcriptome of peripheral blood samples from six distinct clinical groups: healthy volunteers (HV); tolerant patients (TOL); stable patients on minimal immunosuppression (MIS) or maintained on classical immunosuppressive therapy (STA); patients showing either signs of chronic rejection (CR) or acute rejection (AR). The initial studies are the following: -Study 1 from Braud C. et al. (J Cell Biochem., 2008) published under GEO accession number GSE47755 and comprising 250 unique samples (8 HV; 21 TOL; 190 STA; 31 CR). -Study 2 from Brouard S. et al. (Proc Natl Acad Sci U S A., 2007) published under GEO accession number GSE47683 and comprising 67 unique samples (8 HV; 12 TOL; 10 MIS; 12 STA; 11 CR; 14 AR). - Study 3 from Lozano JJ. et al. (Am J Transplant., 2011) published under GEO accession number GSE22707 and comprising 42 unique samples (6 HV; 12 TOL; 12 STA; 12 CR). - Study 4 from Newell KA. et al. (J Clin Invest., 2010) published under GEO accession number GSE22229 and comprising 58 unique samples (12 HV; 19 TOL; 27 STA). - Study 5 from Sagoo P. et al. (J Clin Invest. 2010) published under GEO accession number GSE14655 and comprising two distinct cohorts of patients. The IOT (“Indices of Tolerance”) cohort (5a) corresponds to a European group of patients and totalizes 74 unique samples (8 HV; 10 TOL; 11 MIS; 36 STA; 9 CR). The ITN (“Immune Tolerance in Transplantation”) cohort (5b) corresponds to an American group of patients and totalizes 105 unique samples (20 HV; 22 TOL; 11 MIS; 34 STA; 18 CR). The final data matrix corresponds to the combination of the data from the five independent studies and examines the expression of 1846 meta-genes (MG) across 596 unique blood samples. The 1846 meta-genes correspond to the genes being measured across the five datasets and form a virtual microarray platform (TOL-HUMAN-G1846). The 596 examined samples can be divided into 62 HV, 96 TOL, 32 MIS, 311 STA, 81 CR, and 14 AR.

Project description:Rationale: Interstitial fibrosis and tubular atrophy (IFTA) is found in ~25% of 1-year biopsies post-transplant(1, 2). It correlates with decreased graft survival when histological evidence of inflammation is present¬.(3-5) Identifying the etiology of IFTA is important because longterm graft survival has not changed as expected given improved therapies and a dramatically reduced incidence of acute rejection.(6-8) Methods: Gene expression profiles of 234 samples were obtained with matching clinical and outcome data (7 transplant centers). 81 IFTA samples were divided into subphenotypes by the degree of inflammation on histology: IFTA with acute rejection (AR), IFTA with inflammation and IFTA without inflammation. Samples with AR (n=54) and normally functioning transplants (TX; n=99) were used in comparisons. Conclusions: Gene expression profiling of all IFTA phenotypes were strongly enriched for cAR gene dysregulation pathways, including IFTA samples without histological evidence of inflammation. Thus, by molecular profiling we demonstrate that most IFTA samples have ongoing immune-mediated injury or chronic rejection that is more sensitively detected by gene expression profiling. We also found that the relative expression of AR-affiliated genes correlated with future graft loss in IFTA samples without inflammation. We conclude that undetected and/or undertreated immune rejection is leading to IFTA and graft failure. RNA was extracted from biopsy samples using the RNEasy kit (Qiagen), biotinylated cRNA prepared using Ambion MessageAmp Biotin II and hybridized to Affymetrix HG U133 Plus PM peg arrays (http://affymetrix.com/index.affx). Probe intensity data were log2–transformed and normalized using a custom-designed frozen Robust Multichip Average (fRMA). Low-variance and low signal probes were filtered according to industry standards, resulting in a filtered gene list with 17,564 transcripts. This dataset is part of the TransQST collection.

Project description:Background: Studies recently support that non-HLA antigens could be additional targets of injury in organ transplant recipients, and MICA was associated with an increased risk of graft loss. Methods: A ProtoArray platform was used to study 37 serum samples from 22 unique patients (15 renal recipients and 7 healthy controls). Thirty paired pre- and post-transplant serum samples were analyzed for detection of de novo post-transplant antibody responses in the 15 patients (10 acute rejection (AR), 5 Stable). Probes on ProtoArray and cDNA platforms (GSE: 3931) were re-annotated and compartment specific gene lists were analyzed using the integrated genomics method. Normal and transplant kidney IHC were performed for MICA antigen localization. Results: Mean MICA-Ab (antibody) signal intensity was significantly higher in transplant patients compared with healthy controls and de novo MICA-Ab were detected in 73% transplant patients. The mean post-transplant signal intensity of MICA-Ab was the highest in C4d+AR. Detection of MICA-Ab responses did not correlate with time post-transplantation, but significantly correlated with decline in graft function over the subsequent year. Integrative genomics predicted localization of the MICA antigen to the glomerulus. IHC confirmed cytoplasmic MICA staining solely in glomerular podocytes in normal kidney. In the transplant kidney, infiltrating mononuclear lymphocytes (T, B and NK) in AR had additional MICA staining. Conclusions: MICA can be highly detected regardless of graft dysfunction or AR. The intensity signal of the MICA antibody correlates with subsequent decline in graft function. The MICA antigen localizes to the glomerulus and infiltrating mononuclear cells in AR. Pre- and post-transplant serum antibodies were profiled for each patient, using the Invitrogen ProtoArrayÂ® Human Protein Microarray v3.0 platform (Invitrogen, Carlsbad, CA). This platform contains 5,056 non-redundant human proteins expressed in a baculovirus system, purified from insect cells and printed in duplicate onto a nitrocellulose-coated glass slide. Each protein is spotted twice on each array, to measure the quality of the signal intensity. Details for experiment processing and analysis follow the previous publication from our group (13). Prospector software was used to retrieve the expression based on immune response profiling of the .gal files.

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A common rejection module for acute rejection in multiple organs identifies novel therapeutics.

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