Biliary atresia is associated with polygenic susceptibility in ciliogenesis and planar polarity effector genes.

BACKGROUND & AIMS: Biliary atresia (BA) is poorly understood and leads to liver transplantation (LT), with the requirement for and associated risks of lifelong immunosuppression, in most children. We performed a genome-wide association study (GWAS) to determine the genetic basis of BA. METHODS: We performed a GWAS in 811 European BA cases treated with LT in US, Canadian and UK centers, and 4,654 genetically matched controls. Whole-genome sequencing of 100 cases evaluated synthetic association with rare variants. Functional studies included whole liver transcriptome analysis of 64 BA cases and perturbations in experimental models. RESULTS: A GWAS of common single nucleotide polymorphisms (SNPs), i.e. allele frequencies >1%, identified intronic SNPs rs6446628 in AFAP1 with genome-wide significance (p = 3.93E-8) and rs34599046 in TUSC3 at sub-threshold genome-wide significance (p = 1.34E-7), both supported by credible peaks of neighboring SNPs. Like other previously reported BA-associated genes, AFAP1 and TUSC3 are ciliogenesis and planar polarity effectors (CPLANE). In gene-set-based GWAS, BA was associated with 6,005 SNPs in 102 CPLANE genes (p = 5.84E-15). Compared with non-CPLANE genes, more CPLANE genes harbored rare variants (allele frequency <1%) that were assigned Human Phenotype Ontology terms related to hepatobiliary anomalies by predictive algorithms, 87% vs. 40%, p <0.0001. Rare variants were present in multiple genes distinct from those with BA-associated common variants in most BA cases. AFAP1 and TUSC3 knockdown blocked ciliogenesis in mouse tracheal cells. Inhibition of ciliogenesis caused biliary dysgenesis in zebrafish. AFAP1 and TUSC3 were expressed in fetal liver organoids, as well as fetal and BA livers, but not in normal or disease-control livers. Integrative analysis of BA-associated variants and liver transcripts revealed abnormal vasculogenesis and epithelial tube formation, explaining portal vein anomalies that co-exist with BA. CONCLUSIONS: BA is associated with polygenic susceptibility in CPLANE genes. Rare variants contribute to polygenic risk in vulnerable pathways via unique genes. IMPACT AND IMPLICATIONS: Liver transplantation is needed to cure most children born with biliary atresia, a poorly understood rare disease. Transplant immunosuppression increases the likelihood of life-threatening infections and cancers. To improve care by preventing this disease and its progression to transplantation, we examined its genetic basis. We find that this disease is associated with both common and rare mutations in highly specialized genes which maintain normal communication and movement of cells, and their organization into bile ducts and blood vessels during early development of the human embryo. Because defects in these genes also cause other birth defects, our findings could lead to preventive strategies to lower the incidence of biliary atresia and potentially other birth defects.

Synthesis of novel coumarin appended bis(formylpyrazole) derivatives: Studies on their antimicrobial and antioxidant activities.

A series of novel coumarin pyrazole hybrids of biological interest were synthesized from the hydrazones, carbazones and thiocarbazones via Vilsmeier Haack formylation reaction. These intermediates and formyl pyrazoles were evaluated for antimicrobial and antioxidant activities. Among the series, compounds 6g and 6h showed excellent antimicrobial activity against different bacterial and fungal strains and compounds 7g, 7h were found to be potent antioxidant agents in both DPPH and hydroxyl radical scavenging assays. Further, detailed quantitative structure-activity relationship (QSAR) analysis indicated the molecular parameters that contribute to increased potency of inhibition. The above findings would further encourage our understanding in employing coumarin pyrazole hybrids as potential antibiotic agents for treating infections caused by pathogenic microbes and fungi. Further, it also paves the way for exploration of these compounds as potential therapeutic agents to treat conditions arising because of excessive oxidative damage.

Allospecific CD154+ T cells identify rejection-prone recipients after pediatric small-bowel transplantation.

BACKGROUND: Up to 70% of children with small bowel transplantation (SBTx) experience acute cellular rejection (ACR). Allospecific CD154+ T cells predict liver ACR in children in a novel, 16-hour mixed leukocyte response (MLR) assay, but remain untested in SBTx. METHODS: The expression of CD154 was measured in 4 subsets-naive (N) and memory (M) CD154+ T-helper (Th) and T-cytotoxic (Tc) cells (ie, CD154+ ThN, CD154+ ThM, CD154+ TcN, and CD154+ TcM, respectively)-in the MLR of single blood samples obtained from 32 children with SBTx within 60 days of SBTx biopsy. Children showing ACR in these biopsies were termed Rejectors. The ratio of donor-induced to third-party-induced CD154+ T cells was called the immunoreactivity index (IR). We hypothesized that IR >1 denoted increased donor-specific alloreactivity and increased risk of rejection; in contrast, IR <1 implied decreased risk. CD154 expression was correlated with the expression of CTLA4, a negative T-cell costimulator that antagonizes and is inversely related to CD154 (n = 18). RESULTS: Rejectors showed significantly greater numbers of donor-specific CD154+ T-cell subsets. Logistic regression analysis and leave-one-out cross validation followed by receiver operating characteristic analysis showed that, among the 4 subsets, IR > or =1.23 for CD154+ TcM identified Rejectors with a sensitivity and specificity of 93% and 88%. Also, a significant negative correlation was observed between CD154 expression and CTLA4 expression in allospecific Tc (Spearman's rho = -0.616, P = .006) but not in Th. CONCLUSION: Allospecific CD154+ TcM identify rejection-prone children with SBTx.