Human biliary mucin binds to E-selectin: a possible role in modulation of inflammation

E-selectin, expressed on endothelial cells, mediates adhesion of leukocytes and tumor cells to endothelium. CA19-9 (sialyl-Lewis(a)) and sialyl-Lewis(x) are specific ligands for E-selectin. We have recently shown that mucin-rich culture media from human gallbladder epithelial cells contains CA19-9. In this study, we have tested whether human biliary mucin binds to E-selectin. The ability of mucins to inhibit the adhesion of HL-60 cells to immobilized E-selectin was taken as an index for E-selectin binding. Gallbladder bile, hepatic bile, and culture medium from human gallbladder epithelial cells completely inhibited the adhesion of HL-60 cells to E-selectin. The mucin-rich fractions of human bile exhibited strong inhibition, whereas mucin-free fractions had little effect. In contrast to human bile samples, CA19-9-free medium from cultured dog gallbladder epithelial cells failed to inhibit HL-60 binding. Furthermore, after CA19-9 immunoaffinity chromatography, which selectively extracted CA19-9 from bile, bile samples showed poor inhibition of HL-60 adhesion to immobilized E-selectin. A good correlation was observed between E-selectin binding and CA 19-9 concentrations in bile. Our results show that human bile has E-selectin binding activity that is mediated by the CA19-9 side chain of biliary mucin.     

The use of reconstructed human epidermis for skin absorption testing: Results of the validation study

A formal validation study was performed, in order to investigate whether the commercially-available reconstructed human epidermis (RHE) models, EPISKIN, EpiDerm and SkinEthic, are suitable for in vitro skin absorption testing. The skin types currently recommended in the OECD Test Guideline 428, namely, ex vivo human epidermis and pig skin, were used as references. Based on the promising outcome of the prevalidation study, the panel of test substances was enlarged to nine substances, covering a wider spectrum of physicochemical properties. The substances were tested under both infinite-dose and finite-dose conditions, in ten laboratories, under strictly controlled conditions. The data were subjected to independent statistical analyses. Intra-laboratory and inter-laboratory variability contributed almost equally to the total variability, which was in the same range as that in preceding studies. In general, permeation of the RHE models exceeded that of human epidermis and pig skin (the SkinEthic RHE was found to be the most permeable), yet the ranking of substance permeation through the three tested RHE models and the pig skin reflected the permeation through human epidermis. In addition, both infinite-dose and finite-dose experiments are feasible with RHE models. The RHE models did not show the expected significantly better reproducibility, as compared to excised skin, despite a tendency toward lower variability of the data. Importantly, however, the permeation data showed a sufficient correlation between all the preparations examined. Thus, the RHE models, EPISKIN, EpiDerm and SkinEthic, are appropriate alternatives to human and pig skin, for the in vitro assessment of the permeation and penetration of substances when applied as aqueous solutions.     

Profiling of a suramin-derived compound library at recombinant human P2Y receptors identifies NF272 as a competitive but non-selective P2Y2 receptor antagonist

Purinergic Signalling - Extracellular nucleotides mediate multiple physiological effects such as proliferation, differentiation, or induction of apoptosis through G protein–coupled P2Y...