Infrared transmission spectra of molecules adsorbed on silver island films evaporated on CaF2 have been investigated. The spectra are remarkably simple compared with those of the molecules in the solid state (KBr pellets). Only the vibrational modes which give dipole changes perpendicular to the metal surface are infrared active. In addition, their intensities are about 200 times larger than those of the free molecule. These results can be fully accounted for if the electric field which excites the surface molecule is perpendicular to the local surface of the metal islands and is stronger than the incident electric field. The origin of the absorption enhancement and the surface selection rule is discussed theoretically by using a classical electromagnetic model.

Mps One Binder Kinase Activator (MOB)1A/1B are core components of the Hippo pathway that coactivate large tumor suppressor homolog (LATS) kinases. Mob1a/1b double deficiency in mouse liver (LMob1DKO) results in hyperplasia of oval cells and immature cholangiocytes accompanied by inflammatory cell infiltration and fibrosis. More than half of mutant mice die within 3 wk of birth. All survivors eventually develop liver cancers, particularly combined hepatocellular and cholangiocarcinomas (cHC-CCs) and intrahepatic cholangiocellular carcinomas (ICCs), and die by age 60 wk. Because this phenotype is the most severe among mutant mice lacking a Hippo signaling component, MOB1A/1B constitute the critical hub of Hippo signaling in mammalian liver. LMob1DKO liver cells show hyperproliferation, increased cell saturation density, hepatocyte dedifferentiation, enhanced epithelial–mesenchymal transition and cell migration, and elevated transforming growth factor beta(TGF-β)2/3 production. These changes are strongly dependent on Yes-Associated Protein-1 (Yap1) and partially dependent on PDZ-binding motif (Taz) and Tgfbr2, but independent of connective tissue growth factor (Ctgf). In human liver cancers, YAP1 activation is frequent in cHC-CCs and ICCs and correlates with SMAD family member 2 activation. Drug screening revealed that antiparasitic macrocyclic lactones inhibit YAP1 activation in vitro and in vivo. Targeting YAP1/TAZ with these drugs in combination with inhibition of the TGF-β pathway may be effective treatment for cHC-CCs and ICCs.

These results demonstrate that gene transfer into the liver via rapid tail vein injection can easily be achieved in the rat, which is more than 10 times larger than the mouse, and has significant value for gene function analysis in rats.

A surface-enhanced Infrared reflection spectroscopy has been developed for the characterization of thin organic films on low reflective substrates. The substrates we studied were BaF2, Ge, microscope slide glass, and poly(acrylonltrlle-butadlenestyrene) resin. The sensitivity of the reflection Infrared spectroscopy at these surfaces Is remarkably Improved by evaporating very thin silver films on the sample surfaces. The same results were obtained also by casting thin organic films on metal-coated substrates. The Improvement of the spectral sensitivity Is due to the enhancement of the Incident Infrared field at the metal surfaces. We show that this technique Is promising as a surface analytical tool for semiconductors and Insulators. The optimum optical condHIons to obtain the spectra are discussed experimentally and theoretically.

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Significance The precise roles of E-cadherin in the liver and liver carcinogenesis are still unknown. Here we show that mice lacking E-cadherin in the liver develop spontaneous periportal inflammation via an impaired intrahepatic biliary network, as well as periductal fibrosis, which resembles primary sclerosing cholangitis. Inducible gene knockout studies identified E-cadherin loss in biliary epithelial cells as a causal factor of cholangitis induction, and dysregulated E-cadherin expression was also seen in patients with primary sclerosing cholangitis. E-cadherin loss also significantly accelerates genetically and chemically engineered liver cancer through epithelial–mesenchymal transition, up-regulation of stem cell markers, and ERK activation. Thus, E-cadherin plays critical roles in maintaining homeostasis and suppressing carcinogenesis in the liver.

The carcinogenic mechanism of extrahepatic cholangiocarcinoma (ECC) is unclear, due at least in part to the lack of an appropriate mouse model. Because human studies have reported frequent genetic alterations in the Ras-and TGFβ/SMAD-signaling pathways in ECC, mice with tamoxifen-inducible, duct-cell-specific Kras activation and a TGFβ receptor type 2 (TGFβR2) deletion were first generated by crossing LSL-Kras G12D , Tgfbr2 flox/flox , and K19 CreERT mice (KT-K19 CreERT ). However, KT-K19 CreERT mice showed only mild hyperplasia of biliary epithelial cells (BECs) in the extrahepatic bile duct (EHBD) and died within 7 wk, probably a result of lung adenocarcinomas. Next, to analyze the additional effect of E-cadherin loss, KT-K19 CreERT mice were crossed with CDH1 flox/flox mice (KTC-K19 CreERT ). Surprisingly, KTC-K19 CreERT mice exhibited a markedly thickened EHBD wall accompanied by a swollen gallbladder within 4 wk after tamoxifen administration. Histologically, invasive periductal infiltrating-type ECC with lymphatic metastasis was observed. Time-course analysis of EHBD revealed that recombined BECs lining the bile duct lumen detached due to E-cadherin loss, whereas recombined cells could survive in the peribiliary glands (PBGs), which are considered a BEC stem-cell niche. Detached dying BECs released high levels of IL-33, as determined by microarray analysis using biliary organoids, and stimulated inflammation and a regenerative response by PBGs, leading eventually to ECC development. Cell lineage tracing suggested PBGs as the cellular origin of ECC. IL-33 cooperated with Kras and TGFβR2 mutations in the development of ECC, and anti-IL-33 treatment suppressed ECC development significantly. Thus, this mouse model provided insight into the carcinogenic mechanisms, cellular origin, and potential therapeutic targets of ECC.extrahepatic cholangiocarcinoma | IL-33 | organoid | ILC2 | amphiregulin

We investigated the mechanism of phenotypic plasticity of hepatocytes in a three-dimensional organoid culture system, in which hepatocytic spheroids were embedded within a collagen gel matrix. Hepatocytes expressed several bile duct markers including cytokeratin (CK) 19 soon after culture and underwent branching morphogenesis within the matrix in the presence of insulin and epidermal growth factor. Cultured hepatocytes did not express Delta-like, a specific marker for oval cells and hepatoblasts. Furthermore, hepatocytes isolated from c-kit mutant rats (Ws/Ws), which are defective in proliferation of oval cells, showed essentially the same phenotypic changes as those isolated from control rats. The bile duct-like differentiation of hepatocytes was associated with increased expression of Jagged1, Jagged2, Notch1, and several Notch target genes. CK19 expression and branching morphogenesis were inhibited by dexamethasone, a mitogen-activated protein kinase kinase 1 (MEK1) inhibitor (PD98059), and a phosphatidyl inositol 3-kinase inhibitor (LY294002). After being cultured for more than 3 weeks within the gels, hepatocytes transformed into ductular structures surrounded by basement membranes. Our results suggest that hepatocytes might have the potential to transdifferentiate into bile duct-like cells without acquiring a stem-like phenotype and that this is mediated through specific protein tyrosine phosphorylation pathways.