Heterogeneous requirement of IκB kinase 2 for inflammatory cytokine and matrix metalloproteinase production in rheumatoid arthritis: Implications for therapy

Abstract

Objective. To investigate the potential role of I B kinase 1 (IKK-1) and IKK-2 in the regulation of nuclear factor B (NF-B) activation and the expression of tumor necrosis factor ␣ (TNF␣), as well as interleukin-1␤ (IL-1␤), IL-6, IL-8, vascular endothelial growth factor (VEGF), and matrix metalloproteinases (MMPs), in rheumatoid arthritis (RA).Methods. Recombinant adenoviruses expressing ␤-galactosidase, dominant-negative IKK-1 and IKK-2, or I B␣ were used to infect ex vivo RA synovial membrane cultures and synovial fibroblasts obtained from patients with RA undergoing joint replacement surgery, or human dermal fibroblasts, human umbilical vein endothelialcells(HUVECs),andmonocyte-derivedmacrophages from healthy volunteers. Then, their effect on the spontaneous or stimulus-induced release of inflammatory cytokines, VEGF, and MMPs from RA synovial membrane cells was examined.Results. IKK-2 was not required for lipopolysaccharide (LPS)-induced NF-B activation or TNF␣, IL-6, or IL-8 production in macrophages, but was essential for this process in response to CD40 ligand,

Canonical pathway of nuclear factor κB activation selectively regulates proinflammatory and prothrombotic responses in human atherosclerosis

“…However, reduced NF-B activity in macrophages increased atherosclerotic lesion size (14). Because the involvement of NF-B in the regulation of gene expression is cell type-, stimulus-, and diseasespecific (17,20,21,24), we decided to investigate the involvement of NF-B activation in the regulation of proinflammatory and prothrombotic factors directly in human atherosclerosis disease tissue, the most physiologically relevant system in terms of the human disease.…”

“…In human macrophages, expression of IL-10 has been shown to be NF-B-independent (32), whereas in mouse macrophages, IL-10 has been shown to require NF-B (14,34). Moreover, in contrast to mouse cells, in human macrophages, IKK-2 blockade did not inhibit lipopolysaccharide-induced proinflammatory cytokine production but was able to reduce CD40L-induced cytokine production (17). Furthermore, atherosclerotic lesions in humans and animal models differ in a number of features, which may also contribute to differences between our study and the results from LDL-R Ϫ͞Ϫ mice.…”

“…Adenovirus encoding GFP was from Quantum Biotech (Quebec, Canada). Adenoviruses encoding IB␣ (AdIB␣) and dominant-negative IKK-2 (AdIKK-2dn) were provided by R. De Martin (University of Vienna, Vienna) (16,17). Adenovirus encoding dominant-negative IKK-1 (AdIKK-1dn) was from M. Karin (University of California, San Diego).…”

“…For the supershift assays, nuclear proteins were incubated with antibodies specific for known NF-B components (p50, RelB, c-Rel, p65, and p52; Santa Cruz Biotechnology) before ␥-32 P-labeled NF-B oligonucleotide was added as described (19). All viruses have been used previously in human primary cells, and successful expression was demonstrated (17,18,20,21).…”

BAFF synthesis by rheumatoid synoviocytes is positively controlled by α5β1 integrin stimulation and is negatively regulated by tumor necrosis factor α and toll‐like receptor ligands

“…Bacterial products known as pathogen-associated molecular patterns (PAMPs), such as lipopolysaccharide (LPS) or peptidoglycan, are known to activate FLS by interacting with cellular pattern-recognition receptors (PRRs) present on these cells (15,16). A large number of PRRs, such as Toll-like receptor 2 (TLR-2), TLR-4, and TLR-9, as well as numerous integrins are expressed by FLS, and their expression is increased in response to inflammatory stimuli (16,17).…”