Project description:In transplantation, there is a critical need for non-invasive biomarker platforms for monitoring immunologic rejection. We hypothesized that transplanted tissues release donor specific exosomes into recipient circulation/ bodily fluids, and that the quantitation and profiling of their intra-exosomal cargoes would constitute a novel biomarker platform for monitoring rejection. We tested this hypothesis in a human into mouse xenogeneic islet transplant model, and validated the concept in clinical settings of islet and renal transplantation. In the xenogeneic model, islet transplant exosomes in recipient blood were quantified over long-term follow-up using anti-human leukocyte antigen (HLA) antibody that is only expressed on human islets (p=1.6x10-14). Transplant islet exosomes were purified using anti-HLA antibody conjugated beads and their cargoes contained bona fide islet endocrine hormone markers insulin, glucagon, and somatostatin. Rejection led to significant decrease in transplant islet exosome signal (p=4x10-15), along with distinct changes in its microRNA and proteomic profiles prior to appearance of hyperglycemia. In the clinical settings of islet (n=5) and renal (n=5) transplantation, donor exosomes with respective tissue specificity for islet β cells and renal epithelial cells were reliably characterized in recipient plasma over follow-up (up to 5 years; p=0.0001). Collectively, these findings demonstrate the biomarker potential of transplant exosome characterization for providing a non-invasive window into the conditional state of the transplant tissue.
Project description:In transplantation, there is a critical need for non-invasive biomarker platforms for monitoring immunologic rejection. We hypothesized that transplanted tissues release donor specific exosomes into recipient circulation/ bodily fluids, and that the quantitation and profiling of their intra-exosomal cargoes would constitute a novel biomarker platform for monitoring rejection. We tested this hypothesis in a human into mouse xenogeneic islet transplant model, and validated the concept in clinical settings of islet and renal transplantation. In the xenogeneic model, islet transplant exosomes in recipient blood were quantified over long-term follow-up using anti-human leukocyte antigen (HLA) antibody that is only expressed on human islets (p=1.6x10-14). Transplant islet exosomes were purified using anti-HLA antibody conjugated beads and their cargoes contained bona fide islet endocrine hormone markers insulin, glucagon, and somatostatin. Rejection led to significant decrease in transplant islet exosome signal (p=4x10-15), along with distinct changes in its microRNA and proteomic profiles prior to appearance of hyperglycemia. In the clinical settings of islet (n=5) and renal (n=5) transplantation, donor exosomes with respective tissue specificity for islet β cells and renal epithelial cells were reliably characterized in recipient plasma over follow-up (up to 5 years; p=0.0001). Collectively, these findings demonstrate the biomarker potential of transplant exosome characterization for providing a non-invasive window into the conditional state of the transplant tissue.
Project description:Short-term kidney transplant rejection rates have vastly improved. Unfortunately, the focus is still on clinical acute rejection, whereas patients with no graft dysfunction and subclinical rejection without protocol biopsies would be treated as having no ongoing injury. Molecular diagnostic tests to detect rejection are still reliant on the current gold standard, kidney histology. Our work is the first to examine molecular profiles in matched tissue and blood samples from a prevalent kidney transplant recipient population. We show molecular evidence, in blood and tissue, that subclinical rejection is a precursor of clinical rejection and that non-alloimmune injury to the graft can be distinguished from immune activation. Our work supports consideration of tissue molecular profiling for a comprehensive understanding of noninvasive diagnostics.
Project description:This study aimed to evaluate the diagnostic utility of urinary exosomal microRNAs (miRNAs) in subclinical rejection following kidney transplantation by comparing miRNA expression profiles in urinary exosomes between patients with no evidence of rejection and patients with subclinical T-cell-mediated rejection (sc-TCMR), as confirmed by protocol kidney biopsies performed 3 months after transplantation. To elucidate these differences, a comprehensive miRNA expression analysis was conducted using microarray profiling. Consequently, 38 urinary exosomal miRNAs were detected, among which three were upregulated and five were downregulated in patients with sc-TCMR. To further evaluate the diagnostic value of these miRNAs, quantitative real-time PCR analysis was performed using urinary exosomes collected at the time of protocol biopsy from 70 kidney transplant recipients. This analysis confirmed that miR-5100 and miR-7975 were differentially expressed in patients with sc-TCMR at the time of the 12-month protocol biopsy. Importantly, miR-7975 demonstrated the ability to distinguish among three groups—no evidence of rejection, borderline changes, and sc-TCMR—with high diagnostic accuracy, as indicated by an area under the receiver operating characteristic curve of 0.825. In vitro, exposure of proximal tubular epithelial cells to transforming growth factor-beta 1 resulted in a reduction in miR-7975 expression within urinary exosomes, implicating these cells as a potential source of exosomal miR-7975. Collectively, these findings suggest that urinary exosomal miR-7975 may serve as a promising noninvasive biomarker for diagnosimg and monitoring sc-TCMR, offering valuable insights for future research and clinical applications.
Project description:Background. The lack of noninvasive biomarkers of rejection remains a challenge in the accurate monitoring of deeply buried nerve allografts and precludes optimization of therapeutic intervention. This study aimed to establish the expression profile of circulating microRNAs (miRNAs) during nerve allotransplantation with or without immunosuppression. Methods. Balb/c mice were randomized into 3 experimental groups, that is, (1) untreated isograft (Balb/c → Balb/c), (2) untreated allograft (C57BL/6 → Balb/c), and (3) allograft (C57BL/6 → Balb/c) with FK506 immunosuppression. A 1-cm Balb/c or C57BL/6 donor sciatic nerve graft was transplanted into sciatic nerve gaps created in recipient mice. At 1, 3, 7, 10, and 14 d after nerve transplantation, nerve grafts, whole blood, and sera were obtained for miRNA expression analysis with an miRNA array and subsequent validation with quantitative PCR.
Project description:Background. The lack of noninvasive biomarkers of rejection remains a challenge in the accurate monitoring of deeply buried nerve allografts and precludes optimization of therapeutic intervention. This study aimed to establish the expression profile of circulating microRNAs (miRNAs) during nerve allotransplantation with or without immunosuppression. Methods. Balb/c mice were randomized into 3 experimental groups, that is, (1) untreated isograft (Balb/c → Balb/c), (2) untreated allograft (C57BL/6 → Balb/c), and (3) allograft (C57BL/6 → Balb/c) with FK506 immunosuppression. A 1-cm Balb/c or C57BL/6 donor sciatic nerve graft was transplanted into sciatic nerve gaps created in recipient mice. At 1, 3, 7, 10, and 14 d after nerve transplantation, nerve grafts, whole blood, and sera were obtained for miRNA expression analysis with an miRNA array and subsequent validation with quantitative PCR.
Project description:Liver transplantation is the only lifesaving therapy for patients with irreversible liver failure, and 30% of the recipients experience acute rejection in the first 12 months following transplantation. Acute rejection is diagnosed by core needle biopsy and noninvasive methods for predicting acute rejection could improve clinical care. MicroRNAs (miRNAs) are emerging as biomarkers of clinically significant events. We investigated whether circulating extracellular miRNA profiles in sera matched to liver allograft biopsies predict human liver allograft status. Small RNA sequencing and TaqMan low-density array analysis of RNA from biopsy matched sera identified that liver specific miR-122, and miRs -885, -210, -194, 193b, -192, -148a, -34a and -22 distinguish patients with acute rejection biopsies from those with biopsies without rejection features (false discovery rate of <0.15). We measured absolute levels of these informative 9 miRNAs using quantitative real-time PCR assays. Receiver-operating-characteristic (ROC) curve analysis of circulating levels of miRNA levels validated that all 9 miRNAs discriminate patients with acute rejection in their biopsies from those without rejection in their biopsies (P <0.01 to P<0.0001). A parsimonious diagnostic signature of miR-122 and miR-194 was diagnostic of acute rejection with a sensitivity of 79% (95% confidence interval [CI], 49% to 95%) and a specificity of 88% (95% CI, 64% to 99%) (area under the curve, 0.91; 95% CI, 0.81 to 1.00; P<0.001 by ROC curve analysis). Our findings suggest that a molecular signature of miR-122 and miR-194 in serum offers a noninvasive means of diagnosing acute rejection including mild forms in human liver allografts.