Matrix proteins of basement membrane of intrahepatic bile ducts are degraded in congenital hepatic fibrosis and Caroli's disease

Abstract

Congenital hepatic fibrosis (CHF) and Caroli's disease are though to result from ductal plate malformation, and the basal laminar components play important roles in biliary differentiation during development. To clarify the involvement of basal laminar components in the ductal plate malformation, this study examined the immunohistochemical expression of laminin and type IV collagen in the livers of CHF and Caroli's disease. Using the polycystic kidney (PCK) rat, an animal model of Caroli's disease with CHF, in vivo and in vitro experiments were also performed. Immunostaining showed that basement membrane expression of laminin and type IV collagen around intrahepatic bile ducts was degraded in CHF, Caroli's disease, and the PCK rats. The degradation of laminin and type IV collagen around bile ducts was also observed in foci of cholangiocarcinoma in situ of Caroli's disease. In vitro, PCK cholangiocytes were found to overexpress plasminogen and a serine proteinase, the tissue-type plasminogen activator (tPA). When PCK cholangiocytes were cultured in Matrigel, the amounts of laminin and collagen in the gel were significantly reduced, and addition of alpha2-antiplasmin in the culture medium inhibited the degradation of laminin and collagen in Matrigel. These results suggest that biliary overexpression of plasminogen and tPA leads to the generation of excessive amounts of plasmin, and subsequent plasmin-dependent lysis of the extracellular matrix molecules may contribute to the biliary dysgenesis in CHF and Caroli's disease, including progressive cystic dilatation of the intrahepatic bile ducts in Caroli's disease. In addition, it is suggested that once cholangiocarcinoma in situ develops in the biliary epithelium of CHF and Caroli's disease, it tends to transform into invasive carcinoma, due to instability of the basement membrane of the bile ducts.

α1- and α5-containing Laminins Regulate the Development of Bile Ducts via β1 Integrin Signals

“…It was reported that laminin and type IV collagen, two major components of the basal lamina, were reduced or partly lost around bile ducts in congenital hepatic fibrosis and Caroli disease and in the PCK rat liver, an animal model of Caroli disease (30). Thus, the interactions between laminin and cholangiocytes may also be important for preventing the pathogenesis of fibrosis.…”

Biliary Infection May Exacerbate Biliary Cystogenesis Through the Induction of VEGF in Cholangiocytes of the Polycystic Kidney (PCK) Rat

“…These include increased cell proliferation and apoptosis, enhanced fluid secretion, abnormal cell-matrix interactions, and abnormal ciliary structure or function. [5][6][7][8][9] Although the clinical significance of cholangitis due to biliary infection is well recognized in Caroli's disease, the effect of biliary infection on disease pathogenesis and progression has not been studied previously.…”

Aberrant DNA methylation profile in cholangiocarcinoma

“…Briefly, in renal carcinoma and pancreatic carcinoma, dysregulated IL-10 and Decoy receptor 3 (DcR3) can suppress CⅡTA expression respectively in immune cells through epigenetic modifications on CⅡTA gene promoter [51][52] . Besides leukocytes, much research has also highlighted the pivotal roles of other stroma constituents in the progression of chronic cholangiopathies, encompassing fibroblasts, hepatic stellate cells (HSC), extracellular matrix (ECM), etc [53][54][55][56][57] . Recently stromal effect on parenchyma epithelial-to-mesenchymal transition (EMT) has also been noticed in cholangiopathies [54,[58][59][60] .…”