Vol. 58, Issue 6, 1479-1489, December 2000

Protein Kinase C but not p44/42 Mitogen-Activated Protein Kinase, p38, or c-Jun NH₂-Terminal Kinase Is Required for Intercellular Adhesion Molecule-1 Expression Mediated by Interleukin-1: Involvement of Sequential Activation of Tyrosine Kinase, Nuclear Factor-B-Inducing Kinase, and IB Kinase 2

Ching-Chow Chen, Jun-Jie Chen, and Chian-Ying Chou

Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan

IL-1 induced an increase in ICAM-1 expression in human A549 epithelial cells and immunofluorescence staining confirmed this result. Tyrosine kinase inhibitors (genistein or tyrphostin 23) or phosphatidylcholine-specific phospholipase C inhibitor (D609) attenuated IL-1-induced ICAM-1 expression. IL-1 produced an increase in PKC activity and this effect was abolished by D609. PKC inhibitors (staurosporine, Ro 31-8220, calphostin C, or Go 6976) also inhibited IL-1-induced response. TPA, a PKC activator, stimulated ICAM-1 expression as well, this effect being inhibited by tyrosine kinase inhibitors. Treatment of cells with IL-1 resulted in stimulation of p44/42 MAPK, p38, and JNK. However, neither the mitogen activated protein kinase kinase inhibitor PD 98059 nor the p38 inhibitor SB 203580 affected IL-1-induced ICAM-1 expression. NF-B DNA-protein binding and ICAM-1 promoter activity were enhanced by IL-1 and these effects were inhibited by tyrphostin 23, but not by PD 98059 or SB 203580. TPA also stimulated NF-B DNA-protein binding and ICAM-1 promoter activity as well, these effects being inhibited by tyrosine kinase inhibitors. Dominant-negative PKC, NIK, or IKK2, but not IKK1 mutant, inhibited IL-1- or TPA-induced ICAM-1 promoter activity. IKK activity was stimulated by either IL-1 or TPA, and these effects were inhibited by Ro 31-8220 or tyrphostin 23. Taken together, IL-1 activates phosphatidylcholine-specific phospholipase C and induces activation of PKC and protein tyrosine kinase, resulting in the stimulation of NIK, IKK2, and NF-B in the ICAM-1 promoter, then initiation of ICAM-1 expression. However, activation of p44/42 MAPK, p38, and JNK is not involved.