Molecular Characteristics of Choledochal Cysts in Children: Transcriptome Sequencing

Current status of the biliary tract malformation

The choledochal cyst (CC) can be better termed as biliary tract malformation because of the close association of embryology and etiology in the causation of CC. Contrary to Babbitt's postulation of reflux, damage and dilatation, reflux was not demonstrable as the causative factor in all varieties of CC. High pressure in the biliary system, otherwise termed ductal hypertension, is put forth as an alternative to explain the evolution of CC. The forme fruste type, which does not find a place in the standard classification, typifies the ductal hypertension hypothesis. Hence a closer, in-depth review would be able to highlight this apt terminology of biliary tract malformation.

LncRNA-mRNA coexpression analysis reveals distinct pathogenic mechanisms for subtypes of congenital biliary dilatation

BACKGROUND/PURPOSE

Congenital biliary dilatation (CBD) is a bile duct malformation often associated with pancreaticobiliary maljunction. Different subtypes of CBD have been noted for clinical differences, but their pathogenic mechanisms are unclear.

METHODS

To elucidate the genetic basis of CBD, we performed lncRNA and mRNA sequencing and bioinformatic analysis on 18 cystic and 18 fusiform CBD samples.

RESULTS

We identified differentially expressed mRNAs and lncRNAs between the two types of CBD, and constructed coexpression modules that correlated with clinical characteristics of CBD using weighted gene coexpression network analysis. We found that the brown module was the highest positive correlation with fusiform CBD (R = 0.67, p = 7.9e-6) and contained the most genes. We then built a lncRNA-mRNA coexpression network to identify potential target genes of lncRNAs in CBD, and a protein-protein interaction network to investigate the hub genes from the target genes and the brown module. Finally, we performed enrichment analyses and found differences between cystic and fusiform CBD in hepatobiliary system development, liver and pancreas development involving hub genes ONECUT1 and HNF1B that could be regulated by corresponding lncRNAs.

CONCLUSION

Our study suggests that lncRNAs may modulate pancreaticobiliary duct development differently in cystic and fusiform CBD, providing new insights for etiology studies and clinical treatment.

Pathogenesis of Choledochal Cyst: Insights from Genomics and Transcriptomics

Choledochal cysts (CC) is characterized by extra- and/or intra-hepatic b\ile duct dilations. There are two main theories, “pancreaticobiliary maljunction” and “congenital stenosis of bile ducts” proposed for the pathogenesis of CC. Although family cases or CC associated with other anomalies have been reported, the molecular pathogenesis of CC is still poorly understood. Recent advances in transcriptomics and genomics analysis platforms have unveiled key expression signatures/genes/signaling pathways in the pathogenesis of human diseases including CC. This review summarizes insights from genomics and transcriptomics studies into the pathogenesis of CC, with the aim to improve (i) our understanding of its underlying complex pathomechanisms, and (ii) clinical management of different subtypes of CC, in particular their associated hepatic fibrotic change and their risk of malignancy transformation.

Molecular Mechanisms Linking Risk Factors to Cholangiocarcinoma Development

The poor prognosis of cholangiocarcinoma in humans is related to several factors, such as (i) the heterogeneity of the disease, (ii) the late onset of symptoms and (iii) the limited comprehension of the carcinogenic pathways determining neoplastic changes, which all limit the pursuit of appropriate treatment. Several risk factors have been recognized, including different infective, immune-mediated, and dysmorphogenic disorders of the biliary tree. In this review, we report the details of possible mechanisms that lead a specific premalignant pathological condition to become cholangiocarcinoma. For instance, during liver fluke infection, factors secreted from the worms may play a major role in pathogenesis. In primary sclerosing cholangitis, deregulation of histamine and bile-acid signaling may determine important changes in cellular pathways. The study of these molecular events may also shed some light on the pathogenesis of sporadic (unrelated to risk factors) forms of cholangiocarcinoma, which represent the majority (nearly 75%) of cases.