Identification of ventricle-specific methylation patterns in cell-free DNA and correlation with myocardial apoptosis and acute cellular rejection after heart transplantation
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ABSTRACT: 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: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:Analyzing the kenetics of alveolar macrophage turnover after human lung transplantation and identifying protein and transcriptional differences between donor and recipient-derived alveolar macrophages
Project description:The histological evaluation of liver via biopsy remains as the standard for the diagnosis of both acute cellular rejection (ACR) and recurrent hepatitis C (RHC) after liver transplantation. Nevertheless, it is often difficult to diagnose ACR in HCV-positive recipients because of common co-existing and overlapping morphological changes with RHC. The aim of the study was to identify potential target genes for ACR in recipients with RHC. We analyzed 22 liver biopsy samples obtained from 21 HCV-positive recipients. The clinicopathological diagnoses for the biopsies were ACR-predominant with superimposed RHC in 9 samples (ACR group) and RHC with no ACR (non-ACR group) in the remaining. We compared the transcriptional alterations between the two groups with oligonucleotide microarray and selected 2206 genes which were significantly modulated in ACR. Subsequently we analyzed the regulatory networks in ACR using Ingenuity Pathway Analysis, and focused on 5 genes (IFNAR1, IL-12RB2, NFATC3, BMP2, and CASP8) from the core network as the target genes for ACR. In conclusion, our results demonstrated that novel transcriptome patterns of ACR and concurrent RHC were present and distinct from recipients with only RHC, suggesting that gene expression profiling may have a role in the diagnosis of ACR in recipients with hepatitis C. Keywords: Gene identification in ACR with recurrent HCV infection
Project description:The histological evaluation of liver via biopsy remains as the standard for the diagnosis of both acute cellular rejection (ACR) and recurrent hepatitis C (RHC) after liver transplantation. Nevertheless, it is often difficult to diagnose ACR in HCV-positive recipients because of common co-existing and overlapping morphological changes with RHC. The aim of the study was to identify potential target genes for ACR in recipients with RHC. We analyzed 22 liver biopsy samples obtained from 21 HCV-positive recipients. The clinicopathological diagnoses for the biopsies were ACR-predominant with superimposed RHC in 9 samples (ACR group) and RHC with no ACR (non-ACR group) in the remaining. We compared the transcriptional alterations between the two groups with oligonucleotide microarray and selected 2206 genes which were significantly modulated in ACR. Subsequently we analyzed the regulatory networks in ACR using Ingenuity Pathway Analysis, and focused on 5 genes (IFNAR1, IL-12RB2, NFATC3, BMP2, and CASP8) from the core network as the target genes for ACR. In conclusion, our results demonstrated that novel transcriptome patterns of ACR and concurrent RHC were present and distinct from recipients with only RHC, suggesting that gene expression profiling may have a role in the diagnosis of ACR in recipients with hepatitis C. Keywords: Gene identification in ACR with recurrent HCV infection Of 22 liver biopsy samples, 9 represented the clinicopathological diagnoses for ACR-predominant with superimposed RHC (ACR group) and 13 represented the clinicopathological diagnoses for RHC with no ACR (non-ACR group) .
Project description:Chronic rejection after organ transplantation manifests as immunosuppressant-resistant graft vascular remodeling and fibrosis, which remains the dominant driver of mortality after the first year of heart transplantation. Single-cell RNAseq analysis of MHCII-mismatched heart transplants developing chronic rejection identified graft IL-33 as a stimulator of tissue repair pathways in infiltrating myeloid cells and regulatory T cells (Tregs). Using IL-33-deficient donor mice, it was revealed that graft fibroblast-derived IL-33 potently induced Amphiregulin (Areg) expression by recipient Treg. Areg is an epidermal growth factor secreted by multiple immune cells to shape immunomodulation and tissue repair. In particular, Areg is proposed to play a major role in Treg-mediated muscle, epithelium, and nerve repair. Assessing recipient mice with Treg-specific deletion of Areg demonstrated that this pathway surprisingly contributes to chronic rejection. Specifically, heart transplants from recipients with Areg-deficient Tregs exhibited less vasculopathy and vessel-associated fibrotic niches infiltrated by recipient T cells. Mechanistically, we show that Areg does not impact Treg suppressive function, but that IL-33 mediated Treg-secretion of Areg increases fibroblast proliferation and migration. In total, these studies identify how a dysregulated repair response involving interactions between IL-33+ fibroblasts in the allograft and recipient Treg contributes to the progression of chronic rejection.
Project description:Graft vascular disease (GVD) is a major problem limiting the long-term survival of grafts. To determine the underlying mechanisms of GVD during chronic phase, we performed murine abdominal aorta transplantation. Donor aortas from C57Bl/6 (H-2b) mice were transplanted into C57Bl/6 (H-2b) mice, and we call this group isograft (ISO). Donor aortas from BALB/c (H-2d) mice were transplanted into C57Bl/6 (H-2b) mice, and we call this group allograft (ALLO). In brief, donor abdominal aortas were isolated and the branch vessels were ligated, while the recipient vessels were cut from the midsection using microscopic scissors. The recipient and donor vessels were anastomosed with a cuff suture. 4 weeks after aorta transplantation, the mice were sacrificed for transcriptomic sequencing and analyzing of the aortic grafts.
Project description:Background. Plasma donor-derived cell-free DNA (dd-cfDNA) is used to screen for rejection in heart transplants. We launched the Trifecta-Heart (ClinicalTrials.gov #NCT04707872), an investigator-initiated, prospective trial, to examine the correlations between genome-wide molecular changes in endomyocardial biopsies (EMBs) and plasma dd-cfDNA. The present report analyzes the correlation of plasma dd-cfDNA with the gene expression in EMBs from 4 vanguard centers and compared these correlations with those in 604 kidney transplant biopsies in the Trifecta-Kidney study (ClinicalTrials.gov #NCT04239703). Results. Top transcripts correlating with dd-cfDNA were related to genes increased in rejection such as IFNG-inducible genes (e.g., HLA-DMA), but also with genes induced by injury and expressed in macrophages (e.g., SERPINA1, HMOX1). In gene enrichment analysis, the top dd-cfDNA-correlated genes reflected inflammation and rejection pathways. Dd-cfDNA correlations with rejection genes in EMB were similar to those seen in kidney transplant biopsies, with somewhat stronger correlations for TCMR genes in hearts and ABMR genes in kidneys. However, the correlations with parenchymal injury-induced genes and macrophage genes were much stronger in hearts. Conclusions: In heart transplants in the Trifecta-Heart study, dd-cfDNA correlates significantly with molecular rejection but also with injury and macrophage infiltration, reflecting the proinflammatory properties of injured cardiomyocytes. The relationship supports the utility of dd-cfDNA in the clinical management of heart transplant recipients.
Project description:In order to study the changes of liver protein level in mice with acute cardiac rejection, we established a mouse model of ectopic heart transplantation. According to the matching relationship between recipient and donor, they were divided into the following two groups: allograft group (ALLO), BALB/ C hearts were transplanted into C57BL/6J recipients with complete mismatch of major histocompatibility complex; In the syngeneic transplantation group (ISO), C57BL/6J hearts were transplanted into MHC-matched C57BL/6J recipients. On day 6 after mouse heart transplantation, livers were obtained from recipient mice in the allograft group (n = 3) and from recipient mice in the syngeneic (ISO) group (n = 3). A series of techniques such as protein extraction, enzyme digestion, TMT labeling, HPLC classification, liquid chromatography-mass spectrometry tandem analysis, database search and bioinformation analysis were used to study the quantitative proteome of samples.
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.