Project description:Acute rejection episodes trigger chronic renal allograft vasculopathy. Numerous leukocytes, predominantly monocytes, accumulate in graft blood vessels during reversible acute rejection preceding chronic rejection of rat kidneys. We speculate that they contribute to transplant vasculopathy and set out to characterize them. Allogeneic renal transplantation was performed in the Fischer 344 to Lewis rat strain combination, Lewis isografts served as controls. Leukocytes were harvested by intensive perfusion of graft blood vessels and subjected to flow cytometry, quantitative RT-PCR and genome-wide transcriptional profiling. Kidneys of LEW and F344 rats were transplanted in LEW rats. Five biological replicates were performed for both isogenic and allogenic transplantation. Transcriptomes of allogenics were compared to isogenics on 5 dual-color hybridizations.
Project description:Acute rejection episodes trigger chronic renal allograft vasculopathy. Numerous leukocytes, predominantly monocytes, accumulate in graft blood vessels during reversible acute rejection preceding chronic rejection of rat kidneys. We speculate that they contribute to transplant vasculopathy and set out to characterize them. Allogeneic renal transplantation was performed in the Fischer 344 to Lewis rat strain combination, Lewis isografts served as controls. Leukocytes were harvested by intensive perfusion of graft blood vessels and subjected to flow cytometry, quantitative RT-PCR and genome-wide transcriptional profiling.
Project description:Objective: Apolipoprotein E (Apo E) is a multifunctional protein, originally described in the context of lipoprotein metabolism and cardiovascular disease. More recently, anti-inflammatory functions of ApoE have been documented. ApoE was studied in the context of several inflammatory disorders, but its role in the pathogenesis of acute organ rejection is unknown. In this study, we test the hypothesis that ApoE attenuates acute renal allograft rejection. Materials and methods: The Dark Agouti (DA) to Lewis (Lew) and the Brown Norway (BN) to Lew rat strain combinations were used to investigate fatal acute rejection. In addition, Fischer 344 (F344) kidneys were transplanted to Lew rats to study reversible acute rejection. Isograft recipients and untreated Lew rats were used as controls. ApoE mRNA expression was quantified in intravascular leukocytes accumulating in the blood vessels of renal grafts and in graft tissue. Apo E protein levels were assessed in blood plasma. To test the protective potential of ApoE, recipients of BN kidneys were treated with ApoE-mimetic peptide. Results: Intravascular graft leukocytes and renal tissue obtained from animals undergoing reversible acute rejection expressed increased levels of ApoE mRNA, whereas during fatal rejection, ApoE expression remained unchanged in the BN to Lew rat strain combination or was significantly reduced when DA rats were used as donors of the kidney. On the protein level, no changes in ApoE were seen in plasma. However, we do not know if local leukocytic ApoE expression results in increased ApoE concentrations inside graft blood vessels. Peptide treatment of allograft recipients reversed fatal rejection and significantly improved animal survival. Conclusions: ApoE plays a protective role in acute organ rejection. Further studies are needed to understand the exact mechanism how ApoE reverses acute rejection. dual-color balanced dye-swap design with 4 biological replicates, hybridized on 4 arrays
Project description:Objective: Apolipoprotein E (Apo E) is a multifunctional protein, originally described in the context of lipoprotein metabolism and cardiovascular disease. More recently, anti-inflammatory functions of ApoE have been documented. ApoE was studied in the context of several inflammatory disorders, but its role in the pathogenesis of acute organ rejection is unknown. In this study, we test the hypothesis that ApoE attenuates acute renal allograft rejection. Materials and methods: The Dark Agouti (DA) to Lewis (Lew) and the Brown Norway (BN) to Lew rat strain combinations were used to investigate fatal acute rejection. In addition, Fischer 344 (F344) kidneys were transplanted to Lew rats to study reversible acute rejection. Isograft recipients and untreated Lew rats were used as controls. ApoE mRNA expression was quantified in intravascular leukocytes accumulating in the blood vessels of renal grafts and in graft tissue. Apo E protein levels were assessed in blood plasma. To test the protective potential of ApoE, recipients of BN kidneys were treated with ApoE-mimetic peptide. Results: Intravascular graft leukocytes and renal tissue obtained from animals undergoing reversible acute rejection expressed increased levels of ApoE mRNA, whereas during fatal rejection, ApoE expression remained unchanged in the BN to Lew rat strain combination or was significantly reduced when DA rats were used as donors of the kidney. On the protein level, no changes in ApoE were seen in plasma. However, we do not know if local leukocytic ApoE expression results in increased ApoE concentrations inside graft blood vessels. Peptide treatment of allograft recipients reversed fatal rejection and significantly improved animal survival. Conclusions: ApoE plays a protective role in acute organ rejection. Further studies are needed to understand the exact mechanism how ApoE reverses acute rejection.
Project description:Although pig-to-nonhuman primate (NHP) corneal xenotransplantation has shown long-term graft survival, xenogeneic antigenrelated immune responses are still stronger than allogenic antigen-associated responses. Therefore, there is an unmet need to investigate major rejection pathways in corneal xenotransplantation, even with immunosuppression. This study aimed to identify biomarkers in aqueous humor for predicting rejection and to investigate rejection-related pathways in grafts from NHPs transplanted with porcine corneas following administration of steroids combined with tacrolimus/rituximab. NHPs who had received corneas from wild‐type (WT) or α‐1,3‐galactosyltransferase gene‐knockout (GTKO) pigs were divided into groups with or without rejection according to clinical examinations. Liquid chromatography-mass spectrometry (LC-MS) was used to analyze the proteomes of corneal tissues or aqueous humor. The biological functions of differentially expressed proteins (DEPs) were assessed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) for pathways and protein–protein interaction network analysis. Among the 66 DEPs in aqueous humor, complement proteins (C3, C5, and C9) and cholesterol metabolic proteins (APOA1 and APOA2) were related to xenogeneic rejection as biomarkers, and alternative pathways of the complement system seemed to be important in xenogeneic graft rejection. Among 416 DEPs of the cornea, NF‐κB1 and proteosomes (PSMD7, PSMA5, and PSMD3) seemed to be related with xenogeneic graft rejection. Additionally, oxidative phosphorylation and leukocyte activation‐related pathways are involved in rejection. Overall, our proteomic approach highlights the important role of NF‐κB1, proteosomes, oxidative phosphorylation, and leukocyte activation-related inflammation in the cornea, and the relevance of complement pathways of the aqueous humor as a predictive biomarker of xenogeneic rejection.
Project description:To ensure safety tolerance induction protocols are accompanied by conventional immunosuppressive drugs IS. But IS such as calcineurin inhibitors CNI can interfere with tolerance induction. We investigated the effect of an additional CNI treatment on anti-CD4 mAb-induced tolerance induction upon rat kidney transplantation. Additional CNI treatment induced deteriorated graft function and chronic rejection characterised by alloantibody production, intragraft plasma cells and C3d deposition. Microarray analysis revealed enhanced intragraft expression of the B cell chemokine CXCL13 upon additional CNI treatment. In contrast PNOC, a B cell-related gene highly expressed in operational tolerant kidney transplant recipients, was decreased in grafts of anti-CD4 mAb+CsA-treated recipients suggesting an altered balance of B regulatory genes. Transient B cell depletion or transfer of Tregs three weeks after transplantation could inhibit intragraft B cell accumulation, alloantibody production and ameliorate chronic rejection. These data represent unexpected findings and should be taken into consideration when designing new clinical trials. To safe the benefit of CNI in controlling memory T cell responses we need strategies for a therapeutic optimization. We show here that early B cell depletion or transfer of Tregs may be one approach to arrest B cell accumulation, activation and graft destruction. comparative analysis of different immunosuppressive regimens on renal allograft gene expression versus untreated allografts
Project description:Inducing graft acceptance without chronic immunosuppression remains an elusive goal in organ transplantation. Recent data demonstrate that non-self recognition by graft infiltrating macrophages initiates transplant rejection. Using an experimental transplantation mouse model, we isolated graft-infiltrating macrophages from two transplantation settings: untreated rejecting mice and treated with mTORi-HDL nanobiologics. We used microarrays to detail the global programme of gene expression underlying macrophage dependent organ transplant rejection and identified distinct classes of up-regulated genes during this process, which are down-regulated following tolerogenic treatment with mTORi-HDL nanobiologics.
Project description:The data set contains 67 array (lymphochip cDNA array), published in N Engl J Med 2003 Jul 10;349(2):125-38. PMID: 12853585. TITLE: Molecular heterogeneity in acute renal allograft rejection identified by DNA microarray profiling. BACKGROUND: The causes and clinical course of acute rejection vary, and it is not possible to predict graft outcome reliably on the basis of available clinical, pathological, and genetic markers. We hypothesized that previously unrecognized molecular heterogeneity might underlie some of the variability in the clinical course of acute renal allograft rejection and in its response to treatment. METHODS: We used DNA microarrays in a systematic study of gene-expression patterns in biopsy samples from normal and dysfunctional renal allografts. A combination of exploratory and supervised bioinformatic methods was used to analyze these profiles. : We found consistent differences among the gene-expression patterns associated with acute rejection, nephrotoxic effects of drugs, chronic allograft nephropathy, and normal kidneys. The gene-expression patterns associated with acute rejection suggested at least three possible distinct subtypes of acute rejection that, although indistinguishable by light microscopy, were marked by differences in immune activation and cellular proliferation. Since the gene-expression patterns pointed to substantial variation in the composition of immune infiltrates, we used immunohistochemical staining to define these subtypes further. This analysis revealed a striking association between dense CD20+ B-cell infiltrates and both clinical glucocorticoid resistance (P=0.01) and graft loss (P<0.001). CONCLUSIONS: Systematic analysis of gene-expression patterns provides a window on the biology and pathogenesis of renal allograft rejection. Biopsy samples from patients with acute rejection that are indistinguishable on conventional histologic analysis reveal extensive differences in gene expression, which are associated with differences in immunologic and cellular features and clinical course. The presence of dense clusters of B cells in a biopsy sample was strongly associated with severe graft rejection, suggesting a pivotal role of infiltrating B cells in acute rejection. A disease state experiment design type is where the state of some disease such as infection, pathology, syndrome, etc is studied. Disease State: normal vs disease Keywords: disease_state_design Using regression correlation
Project description:To ensure safety tolerance induction protocols are accompanied by conventional immunosuppressive drugs IS. But IS such as calcineurin inhibitors CNI can interfere with tolerance induction. We investigated the effect of an additional CNI treatment on anti-CD4 mAb-induced tolerance induction upon rat kidney transplantation. Additional CNI treatment induced deteriorated graft function and chronic rejection characterised by alloantibody production, intragraft plasma cells and C3d deposition. Microarray analysis revealed enhanced intragraft expression of the B cell chemokine CXCL13 upon additional CNI treatment. In contrast PNOC, a B cell-related gene highly expressed in operational tolerant kidney transplant recipients, was decreased in grafts of anti-CD4 mAb+CsA-treated recipients suggesting an altered balance of B regulatory genes. Transient B cell depletion or transfer of Tregs three weeks after transplantation could inhibit intragraft B cell accumulation, alloantibody production and ameliorate chronic rejection. These data represent unexpected findings and should be taken into consideration when designing new clinical trials. To safe the benefit of CNI in controlling memory T cell responses we need strategies for a therapeutic optimization. We show here that early B cell depletion or transfer of Tregs may be one approach to arrest B cell accumulation, activation and graft destruction.
Project description:Previous studies of rejection-associated transcript expression in heart transplant biopsies identified not only rejection but a group of early biopsies with injury but no rejection. The present analysis used an expanded population of biopsies to explore parenchymal injury in all biopsies, with or without rejection, and its relationship to function, and outcome. Archetypal analysis defined five injury clusters: no-injury (N=376); mild (N=526); moderate (N=110); severe (N=87); and late (N=221). The late group, 62% of which had no rejection, had molecular characteristics associated with atrophy-fibrosis, depressed LVEF, and increased graft loss independent of rejection status. In random forest analysis, low LVEF was more strongly associated with injury scores than with rejection scores. Three-year graft failure was best predicted using a combination of injury and rejection scores. In heart transplant biopsies, injury-related molecular scores correlate with dysfunction and risk of failure and identify an important new group of late heart transplants, many with no rejection, that have impaired function and a high risk of graft loss. (ClinicalTrials.gov #NCT02670408).