Divergence of tight and adherens junction factors in alveolar epithelium in pulmonary fibrosis

Expression of Tight Junction Components in Hepatocyte-Like Cells Differentiated from Human Embryonic Stem Cells

“…Claudin-5 is usually expressed in endothelial cells [22], but also present in fibrolamellar carcinoma of the liver, in contrast to ordinary hepatocellular carcinoma and cholangiocarcinoma, which lack claudin-5 expression [27,38]. Our findings that claudin-5 is detected during differentiation from HUES9 is consistent with the observation that certain tumors of epithelial origin deriving from different stages of differentiation express claudin-5 [43]. A significant increase in the expression of claudin-7 was observed in hepatocellular carcinoma (HCC) versus nontumorous tissues [30].…”

“…To date the cell contacts and different components of hepatocytes [24,25,27,64]. These TJ components are associated with both cell polarity and permeability [24,25,43]. The combination and mixing ratios of claudin isoforms determine the paracellular permeability in TJs [31,32].…”

“…In contrast to hepatocellular carcinoma (HCC) [7,39], overexpression of claudin-4 has been observed in cholangiocarcinoma [29], in colon cancer [40], in pancreatic ductal carcinoma [41] and in several other malignancies [37,42,43]. Claudin-7 is a prognostic factor for HCC [30].…”

Studies on cell junctions in an ex vivo human lung infection model

“…The reports about claudin-2 expression in the lung are controversial. Claudin-2 is expressed in lung-derived cell lines and mouse lungs [290,291], whereas some studies stated the absence of claudin-2 in the alveolar compartment of normal human lung tissue [282,283]. In this study the positive staining for claudin-2 in the alveolar epithelium and vascular endothelium was found to be of weak extent.…”

“…Only in primary human bronchiolar epithelial cells or cell lines a continuous band-like structure of ZO-1 as well as occludin was shown [280,281]. In this study, the images are maximum [282,283]. To this date bronchiolar epithelial expression of claudin-18 was only found in mice or detected on mRNA level in human lung [206,284].…”