Rheumatoid arthritis (RA) is a chronic inflammatory disease that causes symmetric polyarthritis and joint destruction. Considerable work in the pathogenesis of RA has implicated multiple signaling pathways that regulate the production of pro-inflammatory mediators. NF-kB, in particular, plays a key role, and IkB kinase- 2 (IKK2) is an attractive therapeutic target. However, blockade of this kinase poses major safety concerns. As a result, we have focused on a recently described alternate pathway that activates innate immune responses and NF-kB. The IKK-related kinases, inducible IKK (IKKi) and TANK-binding kinase 1 (TBK1) were as originally identified as NF-kB activating kinases that phosphorylated IkB. It is now clear, however, that this represents only one of several substrates for IKKi. For instance, IKKi phosphorylates interferon regulatory factor 3 (IRF) and coordinates its activation with NF-kB after Toll-like receptor (TLR) ligation. IKKi might also serve to link the NF-kB and CCAAT enhancer binding protein (C/EBP) pathways in LPS stimulated cells. Our preliminary data indicate that IKKi can activate c-Jun and enhance MMP expression in cultured synoviocytes. We hypothesize that IKKi activates both innate and adaptive immunity in RA and represents a novel approach to blocking pathogenic transcription factor activation implicated in synovial inflammation. We propose to assess the role of IKKi in synovial inflammation by first determining the signal transduction pathways activated by IKKi in synoviocytes. We will then determine the function and regulation of IKKi in synovial tissue and synoviocytes from RA patients. Finally, we will determine the role of IKKi in animal models by studying a passive K/BxN model of arthritis in IKKi knockout and wild type mice as well as a collagen-induced arthritis model in IKKi knockout mice crossbred on the DBA/1 background. These experiments will allow an assessment of the potential of IKKi as a therapeutic target in RA. Rheumatoid arthritis (RA) causes joint destruction and significant disability in many patients, affecting up to 1% of the adult population worldwide. Studies of the intracellular pathways activated in RA might lead to prevention and development of novel therapies for this chronic, debilitating disease. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Clinical Investigator Award (CIA) (K08)
Project #
5K08AR052800-02
Application #
7274876
Study Section
Arthritis and Musculoskeletal and Skin Diseases Special Grants Review Committee (AMS)
Program Officer
Mancini, Marie
Project Start
2006-08-10
Project End
2011-07-31
Budget Start
2007-08-01
Budget End
2008-07-31
Support Year
2
Fiscal Year
2007
Total Cost
$120,071
Indirect Cost
Name
University of California San Diego
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
804355790
City
La Jolla
State
CA
Country
United States
Zip Code
92093