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:Translational characterization of hepatic miR-301a as a biomarker for acute rejection in experimental and clinical liver transplantation
Project description:Compromised renal function after renal allograft transplantation often results in anemia in the recipient. Molecular mechanisms leading to anemia during acute rejection are not fully understood; inadequate erythropoietin production and iron deficiency have been reported to be the main contributors. To increase our understanding of the molecular events underlying anemia in acute rejection, we analyzed the gene expression profiles of peripheral blood lymphocytes (PBL) from four pediatric renal allograft recipients with acute rejection and concurrent anemia, using DNA microarrays containing 9000 human cDNA clones (representing 7469 unique genes). In these anemic rejecting patients, an 'erythropoiesis cluster' of 11 down-regulated genes was identified, involved in hemoglobin transcription and synthesis, iron and folate binding and transport. Additionally, some alloimmune response genes were simultaneously down-regulated. An independent data set of 36 PBL samples, some with acute rejection and some with concurrence of acute rejection and anemia, were analyzed to support a possible association between acute rejection and anemia. In conclusion, analysis using DNA microarrays has identified a cluster of genes related to hemoglobin synthesis and/or erythropoeisis that was altered in kidneys with renal allograft rejection compared with normal kidneys. The possible relationship between alterations in the expression of this cluster, reduced renal function, the alloimmune process itself, and other influences on the renal transplant awaits further analysis.