Tumour necrosis factor‐α‐induced ICAM‐1 expression in human vascular endothelial and lung epithelial cells: modulation by tyrosine kinase inhibitors

Abstract

Tumour necrosis factor‐α (TNFα) increases the expression of the adhesion molecule intercellular adhesion molecule‐1 (ICAM‐1) on cultured endothelial and epithelial cells and modulation of this may be important in controlling inflammation. Activation of tyrosine kinase(s) is known to be involved in the signal transduction pathways of many cytokines. In this study we have investigated the effects of the tyrosine kinase inhibitors, ST638, tyrphostin AG 1288 and genistein, on TNFα‐induced ICAM‐1 expression in human alveolar epithelial (A549) and vascular endothelial (EAhy926) cell lines and also normal human lung microvascular endothelial cells (HLMVEC). ICAM‐1 expression on cultured cells was determined by a sensitive enzyme‐linked immunosorbant assay (ELISA). Endothelial or epithelial monolayers were exposed to increasing doses of TNF‐α (0.01–10 ng ml−1), in the presence or absence of either ST638 (3–100 μm), AG 1288 (3–100 μm) or genistein (100 μm) and ICAM‐1 expression was measured at 4 and 24 h. Control experiments examined the effect of ST638 on phorbol 12‐myristate 13‐acetate (PMA, 20 ng ml−1, 4 h)‐stimulated ICAM‐1 and compared it to that of a specific protein kinase C inhibitor, Ro31‐8220 (10 μm). Also, functional consequences of changes in ICAM‐1 expression were assessed by measuring adhesion of 111In‐labelled human neutrophils to EAhy926 endothelial and A549 epithelial monolayers treated with TNFα, in the presence or absence of ST638. ST638 caused a concentration‐dependent reduction in TNFα‐ (0.1–10 ng ml−1‐induced ICAM‐1 on EAhy926 endothelial (at 4 h) and A549 epithelial monolayers (at 4 and 24 h). In contrast, ST638 caused a concentration‐dependent increase in TNFα‐ (0.1–10 ng ml−1‐induced ICAM‐1 on EAhy926 endothelial cells at 24 h. Similar effects were seen with AG 1288 or genistein. ST638 (100 μm) significantly (P < 0.01) inhibited ICAM‐1 expression on HLMVEC endothelial cells induced by 0.01 ng ml−1 TNFα at 4 or 24 h or 0.1 ng ml−1 at 4 h, but increased ICAM‐1 expression induced by 0.1 ng ml−1 TNFα at 24 h. ST638 did not significantly change the expression of PMA‐stimulated ICAM‐1 on either A549 epithelial, EAhy926 or HLMVEC endothelial cells. However, PMA‐induced ICAM‐1 expression was inhibited by Ro31‐8220. Also, treatment of epithelial or endothelial monolayers with TNFα and ST638 altered adhesion of human neutrophils to A549 epithelial or EAhy926 endothelial cells in a manner that corresponded to the alteration in ICAM‐1 expression. These results show that tyrosine kinase inhibitors alter TNFα‐induced ICAM‐1 expression, but that the cell type, concentration of TNFα and time of exposure to this cytokine determine whether expression is decreased or increased by the inhibitor. An increased understanding of the signal transduction pathway(s) involved in TNFα‐induced ICAM‐1 expression on lung epithelial and vascular endothelial cells may be of potential therapeutic value in the treatment of inflammatory disease.

Biomimetic channel modeling local vascular dynamics of pro-inflammatory endothelial changes

“…TNF-a induced increase in endothelial ICAM-1 expression has been well established. 47 A study on their spatial regulation based on localized cytokine treatment is novel and has been detailed in the section on ICAM-1 and F-actin distribution along the channel length. From our particle probe binding based analysis of surface ICAM-1 expression, FSS exposed endothelial cells ( Figure 5(b-ii)) are found to have around two times higher ICAM-1 expression compared to static case ( Figure 5(b-iii)).…”

Caveolae Participate in Tumor Necrosis Factor Receptor 1 Signaling and Internalization in a Human Endothelial Cell Line

“…27,28 To assess the caveolar system in EA.hy926, we initially used transmission electron microscopy. We observed dense clusters of caveolae close to and in some cases communicating with the cell surface, similar to those displayed by ECs in situ ( Figure 1A).…”

Monocyte Migration Through the Alveolar Epithelial Barrier: Adhesion Molecule Mechanisms and Impact of Chemokines

“…ICAM-1 is expressed on type I and type II pneumocytes (19 -22) and is up-regulated in the presence of proinflammatory cytokines (23,24). Other candidates for epithelial-monocyte interaction are the integrin-associated protein CD47 located at the basolateral surface of epithelial cells, which was shown to play an important role in the migratory process of neutrophils through intestinal epithelial cells (25), and the VLA-4 ligand VCAM-1, which has been detected on bronchial (17) and renal epithelium (26,27).…”