CELL-ADHESION MOLECULES IN LIVER-FUNCTION AND PATTERN-FORMATION

In epithelia, adhesive interactions participate in specific histogenet ic events and also instate a morphological polarization that is linked to the vectorial functioning of the epithelium. Cell polarity is a re curring event in differentiation, first observed in the preimplantatio n embryo and then during organogenesis, whereas in oncogenesis a break down of polarity may occur. We review here recent work on adhesive int eractions in the liver parenchyma. We focus on the effect of cell-biom atrix interactions on hepatocyte function and polarization, on the int egration of adhesive cell-cell and cell-matrix interactions, and on th e correlation between structural differentiation and adhesion during h epatic development, regeneration, and oncogenesis. Although highlighti ng morphological differences between the liver and other epithelia, we stress that adhesion-mediated effects such as substratum regulation o f differentiation, feedback control of matrix synthesis, and integrati on of intercellular and cell-matrix interactions, shown to transpire i n the liver, most probably occur in other parenchymal tissues too.