INTERLEUKIN-1-BETA INDUCES TISSUE-SPECIFIC AND CELL-TYPE-SPECIFIC EXPRESSION OF ADHESION MOLECULES IN-VIVO

We examined the tissue distribution of adhesion molecule gene expressi on in mice treated intravenously with interleukin (IL)-1 beta. E-selec tin mRNA expression was selectively induced in the heart by IL-1 beta, but only slight or no induction was observed in other organs. On the other hand, intercellular adhesion molecule-1 mRNA expression was indu cible in all organs examined, although it showed the strongest inducti on in the lung and the weakest responses in the brain and skin. Vascul ar cell adhesion molecule-1 mRNA was also inducible in all organs with the exception of the skin, but it was induced most markedly in the lu ng and the heart. The accessibility of IL-1 beta to the heart was less than that to other organs except the brain. Similar tissue-specific i nduction of these mRNAs was also seen when tumor necrosis factor (TNF) -alpha or lipopolysaccharide was substituted for IL-1 beta. Analysis o f E-selectin mRNA expression in the heart by in situ hybridization ind icated that expression was most prominent in microvascular endothelial cells and some other stromal cells, but this transcript was not seen in the lung. Although intercellular adhesion molecule-1 ruRNA expressi on was restricted to the endothelium lining the capillaries and small arteries in the heart, its distribution in the lung covered not only t he endothelium but also the cells composing the alveolar septa. In con trast, vascular cell adhesion molecule-1 mRNA expression was most prom inent in endothelial cells of larger vessels in both the heart and the lung. Our results demonstrate that expression of adhesion molecules i s tissue- and cell type-specific and that endothelial cells differenti ally express adhesion molecules depending on the size of the blood ves sels.