- Paper Report
- Open Access
Mutated IKK2 inhibits endothelial cell activation
- Cheryl Smythe1
© Biomed Central Ltd 2001
- Received: 26 July 2001
- Accepted: 26 July 2001
- Published: 26 July 2001
The expression of many inflammatory genes in endothelial cells (ECs) is regulated by the transcription factor nuclear factor (NF)-?B. In unstimulated cells, NF-?B remains in the cytosol bound to the inhibitory protein, I?B. Upon stimulation, I?B is phosphorylated by the I?B kinases IKK1 and IKK2. This results in I?B degradation, and thereby allows NF-?B to translocate to the nucleus and induce gene expression. In this study, the authors have examined the role of IKK2 in mediating inflammation, coagulation and angiogenesis, and have discussed its potential as a therapeutic target.
Lipopolysaccharide-induced degradation of I?B was inhibited in human umbilical vein endothelial cells (HUVECs) that expressed dominant-negative IKK2 (dnIKK2). NF-?B was located in the cytosol of control cells and transclocated to the nucleus following stimulation with tumour necrosis factor (TNF). In contrast, NF-?B remained in the cytosol of dnIKK2-expressing cells following TNF stimulation. Induction of vascular cell adhesion molecule (VCAM)-1, interleukin (IL)-8 and E-selectin mRNA expression by IL-1 and TNF was dramatically reduced in dnIKK2 cells compared to controls. Similarly, at the protein level, VCAM-1, E-selectin and intracellular adhesion molecule-1 expression was not induced in the dnIKK2 cells. Reduced expression of adhesion molecules was reflected functionally in reduced adhesion of the dnIKK2-expressing cells to HL-60 cells. Procoagulant activity and angiogenesis were also inhibited in the dnIKK2 cells.
Recombinant adenovirus construction; transduction of HUVECs; immunofluorescence; northern and western blotting; electrophoretic mobility shift assay; ELISA; assays for cell adhesion, coagulation and tube formation
Soares MP, Muniappan A, Kaczmarek E, Koziak K, Wrighton CJ, Steinhauslin F, Ferran C, Winkler H, Bach FH, Anrather J: Adenovirus-mediated expression of a dominant negative mutant of p65/Rel A inhibits proinflammatory gene expression in endothelial cells without sensitizing to apoptosis.
Schmitz ML, Bacher S, Kracht M: I?B-independent control of NF-?B activity by modulatory phosphorylations.
Trends Biochem Sci 2001, 26:186-190.