ABSTRACT: Lung allograft rejection results in the accumulation of low molecular weight hyaluronic acid (LMW-HA), which further propagates inflammation and tissue injury. We have previously shown that therapeutic lymphangiogenesis in a murine model of lung allograft rejection reduced tissue LMW-HA and was associated with improved transplant outcomes. Herein we investigated the use of 4-Methylumbelliferone (4-MU), a known inhibitor of HA synthesis, to alleviate acute allograft rejection in a murine model of lung transplantation. We found that treating mice with 4-MU from day 20-30 post-transplant was sufficient to significantly improve outcomes, characterized by a reduction in T-cell mediated lung inflammation, LMW-HA content and improved pathology scores. In vitro, 4-MU directly attenuated activation, proliferation, and differentiation of naïve CD4+ T-cells into Th1 cells. As 4-MU has already been demonstrated to be safe for human use, we believe examining 4-MU for the treatment of acute lung allograft rejection may be of clinical significance.
Project description:Hyaluronan (HA) is the major glycosaminoglycan in the extracellular matrix involved in the pathogenesis of asthma and other chronic inflammatory diseases. During inflammation there is an increased breakdown of HA, resulting in the local and systemic accumulation of low molecular weight (LMW) HA. Eicosanoids, derived from cytosolic phospholipase A2 group IVA activation, are potent lipid mediators also attributed to acute and chronic inflammation. We investigated the effect of LMW HA on lipidomic profile and global gene expression in PBMCs of patients with mild-to-moderate and severe asthma. We found that LMW HA increased production of 68 unique lipid species, among which PGE2, PGA2, PGD2, PGF2a, 15-HETE, TxB2, 11,12-EET, 14,15 EET, 13-HOTrE(y) and 16 (17) EpDPE were significantly upregulated in severe asthmatics. We also performed a systematic genome-wide expression analysis of LMW HA signaling, confirming its highly immunostimulatory potential. However, in severe asthmatics the LMW HA-induced global gene expression profile showed a comprehensive impairment in interferon signaling, cell apoptosis and cell movement, leading to diminished antiviral responses. Likewise, LMW HA-induced production of IL12 p40, CXCL10, CXCL11 and CCL8was markedly reduced in severe asthmatics. Our findings suggest a previously unforeseen link between extracellular matrix, global lipid production and antiviral responses in the pathogenesis of severe asthma. We used microarray to perform a systematic genome-wide expression analysis of LMW HA effect in peripheral blood mononuclear cells in control subjects, mild-to moderate asthma and severe asthma patients
Project description:In this study, we evaluated transcriptional responses in circulating leukocytes to assess for biomarkers of adverse outcomes in transplant patients after transplantation from a HCV-infected donor. We enrolled renal transplant recipients with and without HCV and performed RNA sequencing on serial samples. CMV DNAemia and allograft rejection outcomes were measured. Regularized logistic regression was utilized to develop gene expression classifiers predictive of clinical outcomes.
Project description:Improved understanding of lung transplant disease states is essential because failure rates are high, often due to chronic lung allograft dysfunction. However, histologic assessment of lung transplant transbronchial biopsies (TBBs) is difficult and often uninterpretable even with 10 pieces. All 242 single-piece TBBs produced reliable transcript measurements. Paired TBB pieces available from 12 patients showed significant similarity but also showed some sampling variance. Alveolar content, as estimated by surfactant transcript expression, was a source of sampling variance. To offset sampling variation, for analysis we selected 152 single-piece TBBs with high surfactant transcripts. Unsupervised archetypal analysis identified four idealized phenotypes (archetypes) and scored biopsies for their similarity to each: normal, T cell-mediated rejection (TCMR; T cell transcripts), antibody-mediated rejection (ABMR)-like (endothelial transcripts), and injury (macrophage transcripts). Molecular TCMR correlated with histologic TCMR. The relationship of molecular scores to histologic ABMR could not be assessed because of the paucity of ABMR in this population. Molecular assessment of single-piece TBBs can be used to classify lung transplant biopsies and correlated with rejection histology. Two or three pieces for each TBB will probably be needed to offset sampling variance.
Project description:Acute cellular rejection is common after lung transplantation and is associated with an increased risk of early chronic rejection. We present combined single cell RNA and T cell receptor sequencing on recipient derived T cells obtained from the bronchoalveolar lavage of three lung transplant recipients with acute cellular rejection and compare them with T cells obtained from the same three patients after clinical treatment of rejection with high-dose, systemic glucocorticoids. At the time of acute cellular rejection, we find an oligoclonal expansion of cytotoxic CD8+ T cells, that all persist as tissue resident memory T cells following successful treatment. Persisting CD8+ allograft-resident T cells have reduced gene expression for cytotoxic mediators following therapy with glucocorticoids. This clonal expansion is discordant with circulating T cell clonal expansion at the time of rejection, suggesting in-situ expansion. These findings pose a potential biological mechanism linking acute cellular rejection to chronic allograft damage.
Project description:The Australian Chronic Allograft Dysfunction (AUSCAD) study is an ongoing single centre cohort study at Westmead hospital in Australia. In this section of the study, we aimed to identify biomarkers for allograft rejection in kidney transplant recipients, 3-months after their transplant. Our study recruited 123 patients, each having protocol renal allograft biopsies taken 3-months post transplantation.
Project description:BACKGROUND: Assessment of gene expression in peripheral blood may provide a noninvasive screening test for allograft rejection. We hypothesized that changes in peripheral blood expression profiles would correlate with biopsy-proven rejection and would resolve after treatment of rejection episodes. METHODS AND RESULTS: We performed a case-control study nested within a cohort of 189 cardiac transplant patients who had blood samples obtained during endomyocardial biopsy (EMB). Using Affymetrix HU133A microarrays, we analyzed whole-blood expression profiles from 3 groups: (1) control samples with negative EMB (n=7); (2) samples obtained during rejection (at least International Society for Heart and Lung Transplantation grade 3A; n=7); and (3) samples obtained after rejection, after treatment and normalization of the EMB (n=7). We identified 91 transcripts differentially expressed in rejection compared with control (false discovery rate <0.10). In postrejection samples, 98% of transcripts returned toward control levels, displaying an intermediate expression profile for patients with treated rejection (P<0.0001). Cluster analysis of the 40 transcripts with >25% change in expression levels during rejection demonstrated good discrimination between control and rejection samples and verified the intermediate expression profile of postrejection samples. Quantitative real-time polymerase chain reaction confirmed significant differential expression for the predictive markers CFLAR and SOD2 (UniGene ID No. 355724 and No. 384944). CONCLUSIONS: These data demonstrate that peripheral blood expression profiles correlate with biopsy-proven allograft rejection. Intermediate expression profiles of treated rejection suggest persistent immune activation despite normalization of the EMB. If validated in larger studies, expression profiling may prove to be a more sensitive screening test for allograft rejection than EMB. Experiment Overall Design: Case- control study with three groups. Patients with rejection (r1-r7), follow-up samples after treatment of rejection (post1-7), and controls with no rejection (con1-7)
Project description:Gene expression data was analyzed to map with urine proteomics data gene expression data from kidney biopsies from kidney transplant patients with and without acute rejection, chronic allograft nephropathy and BK virus nephritis was used to study gene expression changes during acute rejection, chronic allograft nephropathy and bk virus nephropathy. Samples labeled STA16, STA22, STA14, and STA18 were included in the CAN vs no-CAN analysis as no-CAN samples as they also qualified as non-CAN samples.
Project description:Histological features of acute rejection can be detected in surveillance biopsies despite stable graft function and can negatively impact graft outcomes. However, routine surveillance biopsies for detection of subclinical rejection are not generally performed due to potential risks and costs associated with repeated biopsies. Noninvasive biomarkers are required to facilitate early detection of acute rejection and borderline changes. We examined the impact of histological abnormalities at 3-month in surveillance biopsies on graft outcomes in kidney transplant recipients from the prospective Genomics of Chronic Allograft Rejection (GoCAR) study. We then performed RNA sequencing on whole blood collected at the time of biopsy in 88 patients (22 vs. 66) to identify transcripts associated with histological abnormalities. Subjects with subclinical ACR or borderline ACR at 3 month (ACR-3) had higher risk of subsequent clinical acute rejection at 12 and 24 month (P < 0.05), more rapid functional decline (P < 0.05) and a decreased graft survival in adjusted cox analysis (P < 0.01) than patients with no abnormalities on 3-month biopsy. We then identified a 17-gene signature in peripheral blood that accurately diagnosed ACR-3.
Project description:Abstract: Immunological memory specific to previously encountered antigens is a cardinal feature of adaptive lymphoid cells. It is not known however whether innate myeloid cells retain memory of prior antigenic stimulation and respond to it more vigorously upon a second encounter. Here, we show that murine monocytes and macrophages acquire memory specific to MHC-I antigens and identify paired immunoglobulin-like receptors-A (PIR-A) as the MHC-I receptors necessary for the memory response. We demonstrate that deleting PIR-A in the recipient or blocking PIR-A binding to donor MHC-I molecules blocks memory and attenuates kidney and heart allograft rejection. Thus, innate myeloid cells acquire alloantigen-specific memory that can be targeted to improve transplant outcomes. Data purpose: Targeting monocyte and macrophage receptors that detect MHC antigens blocks innate immune memory and attenuates transplant rejection