Project description:Cellular rejection after heart transplantation imparts significant morbidity and mortality. Current immunosuppressive strategies are imperfect, target recipient T-cells, and have adverse effects. The innate immune response plays an essential role in the recruitment and activation of T-cells. Targeting the donor innate immune response would represent the earliest interventional opportunity within the immune response cascade. There is limited knowledge regarding donor immune cell types and functions in the setting of cardiac transplantation and no current therapeutics exist for targeting these cell populations. Distinct populations of donor and recipient macrophages co-exist within the transplanted heart. Donor CCR2+ macrophages are key mediators of allograft rejection and deletion of MYD88 signaling in donor macrophages is sufficient to suppress rejection and extend allograft survival. This highlights the therapeutic potential of donor heart-based interventions.
Project description:Acute rejection in cardiac transplant patients is still a contributing factor to limited survival of the implanted heart. Currently there are no biomarkers in clinical use that can predict, at the time of transplantation, the likelihood of post-transplantation acute rejection, which would be of great importance for personalizing immunosuppressive treatment. Within the Biomarkers in Transplantation initiative, the predictive biomarker discovery focused on data and samples collected before or during transplantation such as: clinical variables, genes and proteins from the recipient, and genes from the donor. Based on this study, the best predictive biomarker panel contains genes from the recipient whole blood and from donor endomyocardial tissue and has an estimated area under the curve of 0.90. This biomarker panel provides clinically relevant prediction power and may help personalize immunosuppressive treatment and frequency of rejection monitoring.
Project description:Increased levels of donor-derived cell-free DNA (dd-cfDNA) in recipient plasma have been associated with acute cellular rejection (ACR) after heart transplantation. DNA sequence differences have been used to distinguish between donor and recipient cfDNA but epigenetic differences could also potentially identify dd-cfDNA. This study aimed to assess the feasibility of using ventricle-specific methylation patterns in human cfDNA as an alternative biomarker for ACR in cardiac transplantation.
Project description:Renal dendritic cells play key roles in renal homeostasis and during kidney allograft rejection. Microarray analysis aims to evaluate whether dendritic cells modulate their gene expression profile in relation to their distribution in the different renal compartments (with varying biophysical characteristics), under homeostatic conditions and during acute renal allograft rejection (3 days post-transplantation). Renal dendritic cells from homeostatic (healthy) kidneys and donor/host dendritic cells from renal allografts (3 days post-kidney transplantation) were isolated from cortex and medulla, through fluorescence-activated cell sorting (FACS). Total RNA was isolated from FACS-sorted cells and amplified. The cDNA product was fragmented, biotin-labeled and hybridized on Affimetrix arrays.
Project description:Solid organ transplantation in the mouse is a powerful research tool that has provided a pathway to find important mechanistic insights into the regulation of allograft injury, allograft immunopathology, and transplant rejection/tolerance, and that has unique advantages over transplantation in larger species, due to the well characterization of mouse genome and availability of genetically modified animals. However, setup of mouse liver, heart and kidney transplantation is a technically demanding surgical procedure, especially the orthotopic liver transplantation in mouse. Here, we performed Microwell-based single cell RNA-seq of three mouse organ transplantation models (liver, heart and kidney). Comparison of lymphocytes, parenchyma cells and peripheral blood mononuclear cells in liver, heart and kidney revealed distinct immune microenvironment at acute rejection and tolerance state respectively. Single-cell transcriptome analysis of mouse allograft without immunosuppressive drugs provided rich resources to help understand functioning solid-organ transplantation in human.
Project description:To determine the circRNA expression profile in hepar tissues of 12h after brain death donor liver transplantation and matched non-brain death donor liver transplantation, we uesed circRNA microArray analysis form Arraystar to examine the expression of circRNAs and circRNAs in hepar tissues of 12h after brain death donor liver transplantation and matched non-brain death donor liver transplantation.
Project description:Acute cellular rejection occurs frequently during the first few weeks following liver transplantation. During this period its molecular phenotype is confounded by pro-inflammatory events elicited by surgery, ischemia-reperfusion injury and early post-transplant complications. To unambiguously define the molecular profile associated with rejection we collected sequential biological specimens from liver transplant patients at least 3 years after transplantation who developed rejection while enrolled in trials of intentional immunosuppression withdrawal Transcriptomic RISET 2.0 chips were employed using portal blood vein from 37 liver trasplant patients.Two timepoints were selected: before immunosupressive weaning and rejection time point.
Project description:To illustrate the functional heterogeneity of T cells in the heart allograft rejection,we established the murine heterotopic heart transplantation model and isolated CD45 positive cells from cardiac grafts and spleens for single cell transcriptome and TCR sequencing.