Genetic Variants in Major Histocompatibility Complex-Linked Genes Associate With Pediatric Liver Transplant Rejection

American Journal of Transplantation

Higgs

et al. 2016

T-cell suppression prevents acute cellular rejection but causes life-threatening infections and malignancies. Previously, liver transplant (LTx) rejection in children was associated with the SNP rs9296068 upstream of the HLA-DOA gene. HLA-DOA inhibits B-cell presentation of antigen, a potentially novel anti-rejection drug target. Using archived samples from 122 Caucasian pediatric LTx (including 77 described previously), we now confirm the association between rs9296068 and LTx rejection (p=0.001, OR=2.55). Next-generation sequencing reveals that the putative transcription-factor-(CTCF)-binding SNP locus rs2395304, in linkage disequilibrium with rs9296068 (D’=0.578, r2=0.4), also associates with LTx rejection (p=0.008, OR=2.34). Further, LTx rejection is associated with enhanced B-cell presentation of donor antigen relative to HLA-non-identical antigen in a novel cell-based assay, and with a downregulated HLA-DOA gene in a subset of these children. In lymphoblastoid B-(Raji) cells, rs2395304 co-immunoprecipitates with CTCF, and CTCF knockdown with morpholino antisense oligonucleotides enhances alloantigen presentation and downregulates the HLA-DOA gene, reproducing observations made with HLA-DOA knockdown and clinical rejection. Alloantigen presentation is suppressed by inhibitors of methylation and histone deacetylation, reproducing observations made during resolution of rejection. Enhanced donor antigen presentation by B-cells and its epigenetic dysregulation via the HLA-DOA gene represent novel opportunities for surveillance and treatment of transplant rejection.

Section: Discussionmentioning

confidence: 90%

Section: Resultsmentioning

confidence: 99%

Enhanced B Cell Alloantigen Presentation and Its Epigenetic Dysregulation in Liver Transplant Rejection

American Journal of Transplantation

Higgs

et al. 2016

“…Using previously described methods, RNA was extracted from pre-perfusion liver allograft biopsies obtained at LTx from children with HBL53.…”

Section: Methodsmentioning

confidence: 99%

Loss of EGFR-ASAP1 signaling in metastatic and unresectable hepatoblastoma

Ranganathan

et al. 2016

Sci Rep

Self Cite

Hepatoblastoma (HBL), the most common childhood liver cancer is cured with surgical resection after chemotherapy or with liver transplantation if local invasion and multifocality preclude resection. However, variable survival rates of 60–80% and debilitating chemotherapy sequelae argue for more informed treatment selection, which is not possible by grading the Wnt-β-catenin over activity present in most HBL tumors. A hypothesis-generating whole transcriptome analysis shows that HBL tumors removed at transplantation are enriched most for cancer signaling pathways which depend predominantly on epidermal growth factor (EGF) signaling, and to a lesser extent, on aberrant Wnt-β-catenin signaling. We therefore evaluated whether EGFR, ASAP1, ERBB2 and ERBB4, which signal downstream after ligation of EGF, and which show aberrant expression in several other invasive cancers, would also predict HBL tumor invasiveness. Immunohistochemistry of HBL tumors (n = 60), which are histologically heterogeneous, shows that compared with well-differentiated fetal cells, less differentiated embryonal and undifferentiated small cells (SCU) progressively lose EGFR and ASAP1 expression. This trend is exaggerated in unresectable, locally invasive or metastatic tumors, in which embryonal tumor cells are EGFR-negative, while SCU cells are EGFR-negative and ASAP1-negative. Loss of EGFR-ASAP1 signaling characterizes undifferentiated and invasive HBL. EGFR-expressing HBL tumors present novel therapeutic targeting opportunities.

“…13 Quantitative real-time PCR replication was performed with TaqMan probes (Applied Biosystems). For analysis, the cycle threshold (Ct) value and the relative Ct method was used.…”

Section: Study Proceduresmentioning

confidence: 99%

“…After antigen retrieval with CC1 at 100°C for 32 minutes (Ventana Medical Systems, Tucson, AZ), slides were stained in batches on a Ventana immunostainer (DAKO M7050 at 1:100, Ventana CCI mild, 32 minutes at 32°C, iView 3,3=-diaminobenzidine detection) as described previously. 13 Primary antibodies were to CD163 (mouse monoclonal; Vector Laboratories, Burlingame, CA) a generic macrophage marker, CD14 (rabbit monoclonal; Vector Laboratories), and CCL5 (mouse monoclonal; Lifespan Biosciences, Seattle, WA). Peroxidase-labeled secondary antibodies were used as final stain.…”

Section: Tissue Immunohistochemistrymentioning

confidence: 99%

Increased Expression of Peripheral Blood Leukocyte Genes Implicate CD14+ Tissue Macrophages in Cellular Intestine Allograft Rejection

The American Journal of Pathology

Ranganathan

et al. 2011

Self Cite

Recurrent rejection shortens graft survival after intestinal transplantation (ITx) in children, most of whom also experience early acute cellular rejection (rejectors). To elucidate mechanisms common to early and recurrent rejection, we used a test cohort of 20 recipients to test the hypothesis that candidate peripheral blood leukocyte genes that trigger rejection episodes would be evident late after ITx during quiescent periods in genome-wide gene expression analysis and would achieve quantitative real-time PCR replication pre-ITx (another quiescent period) and in the early post-ITx period during first rejection episodes. Eight genes were significantly up-regulated among rejectors in the late post-ITx and pre-ITx periods, compared with nonrejectors: TBX21, CCL5, GNLY, SLAMF7, TGFBR3, NKG7, SYNE1, and GK5. Only