Single Nucleus RNA Sequencing of Human Kidney Allografts with Cellular Rejection
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ABSTRACT: Kidney transplant recipients are currently treated with nonspecific immunosuppressants that cause severe systemic side effects. Current immunosuppressants were developed based on their effect on T-cell activation rather than the underlying mechanisms driving alloimmune responses. Thus, understanding the role of the intragraft microenvironment will help us identify more directed therapies with lower side effects. To understand the role of the alloimmune response and the intragraft microenvironment in cellular rejection progression, we conducted a Single nucleus RNA sequencing (snRNA-seq) on one human non-rejecting kidney allograft sample, one borderline sample, and T-cell mediated rejection (TCMR) sample (Banff IIa). We studied the differential gene expression and enriched pathways in different conditions, in addition to ligand-receptor (LR) interactions.Pathway analysis of T-cells in borderline sample showed enrichment for allograft rejection pathway, suggesting that the borderline sample reflects an early rejection. Hence, this allows for studying the early stages of cellular rejection. Moreover, we showed that focal adhesion (FA), IFNg pathways, and endomucin (EMCN) were significantly upregulated in endothelial cell clusters (ECs) of borderline compared to ECs TCMR. Furthermore, we found that pericytes in TCMR seem to favor endothelial permeability compared to borderline. Similarly, T-cells interaction with ECs in borderline differs from TCMR by involving DAMPS-TLRs interactions. Our data revealed novel roles of T-cells, ECs, and pericytes in cellular rejection progression, providing new clues on the pathophysiology of allograft rejection.
Project description:Acute rejection of human allografts has been viewed mostly through the lens of adaptive immunity, and the intragraft landscape of innate immunity genes has not been characterized in an unbiased fashion. We did RNA sequencing of 34 kidney allograft biopsy specimens from 34 adult recipients; 16 were categorized as Banff acute T-cell mediated rejection (TCMR) and 18 as normal. Computational analysis of intragraft mRNA transcriptome identified significantly higher abundance of mRNA for pattern recognition receptors in TCMR compared to normal biopsies, as well as increased expression of mRNAs for cytokines, chemokines, interferons, and caspases. Intragraft levels of calcineurin mRNA were higher in TCMR biopsies suggesting under immunosuppression compared to normal biopsies. Cell-type enrichment analysis revealed higher abundance of dendritic cells and macrophages in TCMR biopsies. Damage associated molecular patterns, the endogenous ligands for pattern recognition receptors, as well markers of DNA damage were higher in TCMR. mRNA expression patterns supported increased calcium flux and indices of endoplasmic, cellular oxidative, and mitochondrial stress were higher in TCMR. Expression of mRNAs in major metabolic pathways were decreased in TCMR. Our global and unbiased transcriptome profiling identified heightened expression of innate immune system genes during an episode of TCMR in human kidney allografts.
Project description:The enigmatic natural killer (NK) cells mediate spontaneous cell-mediated cytotoxicity and antibody-dependent cell-mediated cytotoxicity via cell surface Fc receptors. The dual functionality of NK cells may enable their participation in chronic active antibody-mediated rejection (CA-ABMR), wherein evidence for complement activation is inconsistent. We RNA sequenced 57 human kidney allograft biopsies to determine whether NK cell cytotoxicity pathway gene set enrichment is an attribute of CA-ABMR. Among the 15,910 intragraft-expressed genes, 60 were uniquely overexpressed in CA-ABMR compared to active antibody-mediated rejection (active-ABMR) or acute T cell-mediated rejection (TCMR), versus no rejection (NR) biopsies. Cell type annotation showed enrichment for T cells and NK cells, and molecular pathways related to T cells and NK cells in CA-ABMR versus active-ABMR biopsies. NK cell cytotoxicity gene set enrichment in CA-ABMR than in ABMR biopsies, but not in TCMR, was confirmed by gene set variation analysis. Cellular deconvolution analysis divulged a higher proportion of NK cells in CA-ABMR compared to active-ABMR, but not in TCMR; immunohistochemistry of 138 consecutive clinically indicated allograft biopsies validated a higher proportion of CD56+ NK cells in CA-ABMR. Principal component analysis of deconvolved immune cell transcriptomes separated CA-ABMR and TCMR from active-ABMR and NR biopsies. NK cell cytotoxicity pathway gene set was found to be enriched in rejection compared to no rejection biopsies in two publicly available kidney allograft microarray datasets. Altogether, CA-ABMR is exemplified by the overexpression of the NK cell pathway, and, surprisingly, compared to active-ABMR, is exemplified by key gene sets that are similar to TCMR.
Project description:CD4 T and B cells are considered pivotal in driving immune responses in the context of allograft rejection. However, CD4 T and B cell transcriptional profiles according to type of allograft rejection is poorly characterized. We used scRNAseq to profile blood CD4 T and B cells in antibody-mediated rejection (ABMR), T cell mediated rejection (TCMR) and patients without rejection (STABLE).
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.
Project description:Banff 2019 update of kidney allograft pathology excluded isolated tubulitis without interstitial inflammation (ISO-T) from category of borderline (suspicious) for acute T cell-mediated rejection due to its proposed benign clinical outcome. However, molecular assessment of ISO-T has not been explored yet. ISO-T or interstitial inflammation with tubulitis (I+T) were diagnosed in indication biopsies within first 14 postoperative days. Molecular patterns of ISO-T was compared to I+T either by using RNA sequencing (n=16) or by Molecular Microscope Diagnostic System (MMDx, n=51). In ISO-T group, RNA sequencing showed lower expression of genes related to interferon-y (p=1.5 *10-16), cytokine signaling (p=2.1 *10-20) and inflammatory response (p=1.0*10-13) than in I+T groups. Increased transcripts in I+T group had significant overlap with previously described pathogenesis-based transcript sets associated with T cell-mediated rejection (TCMR), cytotoxic and effector T cell transcripts. In ISO-T, MMDx classified biopsies as no-rejection in 25/32 (78%) while in I+T in 12/19 (63%). ISO-T had significantly lower MMDx scores for interstitial inflammation (p=0.014), tubulitis (p=0.035) and TCMR (p=0.016) compared to I+T. Less inflammatory molecular signals of isolated tubulitis suggest its benign phenotype also on molecular level.
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. A disease state experiment design type is where the state of some disease such as infection, pathology, syndrome, etc is studied. Keywords: disease_state_design
Project description:Intimal arteritis is known to be a negative prognostic factor for kidney allograft survival. Although Banff classification assesses isolated v-lesion (IV) as a T-cell mediated rejection, its origin and significance remain unclear. To help resolve if IV truly represents acute rejection, molecular study was performed. Transcriptome of early IV, T cell-mediated vascular rejection (TCMRV) and nonrejection histologic findings was compared using microarrays (Illumina Human HT-12 v4 Expression BeadChips). The enrichment of deregulated genes was analysed using DAVID. Differential gene expression analysis identified 310 genes to be deregulated in TCMRV compared to IV. Gene enrichment analysis categorized deregulated genes to be associated with immune and inflammatory response. Principal component and unsupervised hierarchical cluster analysis revealed clear distinction of TCMRV samples but showed similarity of IV with control group. RT-qPCR validation on external sample set (n=20) confirmed upregulation of genes involved in immune response in TCMRV compared to IV. Based on stepwise logistic regression SLA2 gene represented the strongest group classifier [OR 0.106 (95 % CI 0.01- 0.774), p=0.03] with ROC AUC 0.906 [95% CI (0.769-1.0), p=0.003)]. IV reveals weak immunologic signature compared to TCMRV but shows similarity with non-rejection findings. Early IV in a DSA- and C4d- negative patients may feature non-rejection origin and reflect injury distinct from alloimmune response. Study calls for reassessment of current Banff histopathology criteria which considers an intimal arteritis to be TCMR irrespective of TI and supports use of molecular diagnostics as a part of integrative approach.
Project description:The study comprises various components: We aim to screen out different gene expression profile in acute rejection on the kidney. We aim to screen out different gene expression profile in acute tubular necrosis on the kidney. We aim to screen out different gene expression profile in borderline change on the kidney. We aim to screen out different gene expression profile in non-rejection on the kidney. We aim to screen out different gene expression profile in presumed rejection on the kidney. We aim to screen out different gene expression profile in renal recipients with stable function. Results from the various study components can help to diagnose renal allograft dysfunction with different causes by distinct gene expression profile. Keywords: acute rejection, acute tubular necrosis, borderline change, non-rejection, presumed rejection, renal recipients with stable function,
Project description:Most kidney transplant patients who undergo biopsies are classified as having no rejection based on consensus thresholds. However, we hypothesized that because these patients have normal adaptive immune systems, T cell-mediated rejection (TCMR) and antibody-mediated rejection (ABMR) may exist as subthreshold activity in some transplants currently classified as no rejection. Subthreshold molecular TCMR and/or ABMR activity molecular activity was detectable as elevated classifier scores in many biopsies classified as no rejection, with ABMR activity in many TCMR biopsies and TCMR activity in many ABMR biopsies. In biopsies classified as no rejection histologically and molecularly, molecular TCMR classifier scores correlated with increases in histologic TCMR features and molecular injury, lower eGFR, and higher risk of graft loss, and molecular ABMR activity correlated with increased glomerulitis and donor-specific antibody. No rejection biopsies with high subthreshold TCMR or ABMR activity had a higher probability of having TCMR or ABMR respectively diagnosed in a future biopsy. We conclude that many kidney transplant recipients have unrecognized subthreshold TCMR or ABMR activity, with significant implications for future problems.
Project description:Polyoma virus nephropathy (PVAN) is a common cause of kidney allograft dysfunction and loss. Microscopic descriptions of PVAN are very similar to T-cell mediated rejection (TCMR) and have unclear underlying molecular mechanisms. To identify PVAN-specific gene expression, we analyzed 162 kidney biopsies with and without PVAN for global gene expression. Unsupervised hierarchical clustering analysis of all 162 biopsies revealed high similarity between PVAN and TCMR gene expression. Increasing the stringency for the specificity (p <0.001 and >2-fold expression) between PVAN and TCMR, 158 and 252 unique PVAN and TCMR injury-specific probesets were observed, respectively. While TCMR-specific probeset were overwhelmingly involved in immune response costimulation (CTLA4, CD28, CD86) and TCR (NFATC2, LCP2) signaling, PVAN-specific probesets were mainly related to viral replication process (IFITM1, LTF, NOSIP, RARRES3), RNA polymerase assembly (POLR2l, TAF10, RPS15) and pathogen recognition receptors (C1QA, C3, CFD). A principal component analysis using these genes further confirmed the most optimal separation between the 3 different clinical phenotypes. Validation of 4 PVAN-specific probesets (RPS15, CFD, LTF, and NOSIP) by QPCR and further confirmation by IHC of 2 PVAN-specific proteins with anti-viral function (LTF and IFITM1) was done, showing significantly higher expression within interstitial cellular infiltrates and in tubuli in PVAN specimens as compared to TCMR and NL kidney biopsies. In conclusion, even though PVAN and TCMR kidney allografts share great similarities on gene perturbation, particular PVAN-specific transcripts were identified with well-known anti-viral properties that provide tools for discerning PVAN and AR as well as attractive targets for rational drug design. A total of 168 kidney biopsies from kidney transplant patients were used. The kidney biopsies included renal biopsies from PVAN (n=10), T cell mediated cellular rejection (n=26), patients with IFTA (n=59), patients with stable grafts (STA) (n=73). This dataset is part of the TransQST collection.