Chemokines and Chemokine Receptors as Novel Therapeutic Targets in Rheumatoid Arthritis (RA): Inhibitory Effects of Traditional Chinese Medicinal Components

Chemokines belong to a large family of inflammatory cytokines responsible for migration and accumulation of leukocytes at inflammatory sites. Over the past decade, accumulating evidence indicated a crucial role for chemokines and chemokine receptors in the pathophysiology of rheumatoid arthritis (RA). RA is a chronic autoimmune disease in which the synovial tissue is heavily infiltrated by leukocytes. Chemokines play an important role in the infiltration, localization, retention of infiltrating leukocytes and generation of ectopic germinal centers in the inflamed synovium. Recent evidence also suggests that identification of inhibitors directly targeting chemokines or their receptors may provide a novel therapeutic strategy in RA. Traditional Chinese medicinals (TCMs) have a long history in the treatment of inflammatory joint disease. The basis for the clinical benefits of TCM remains largely unclear. Our studies have led to the identification of numerous novel chemokine/ chemokine receptor inhibitors present in anti-inflammatory TCMs. All of these inhibitors were previously reported by other researchers to have anti-arthritic effect, which may be attributable, at least in part, to their inhibitory effect on chemokine and/or chemokine receptor. Therefore, identification of agents capable of targeting chemokine/ chemokine receptor interactions has suggested a mechanism of action for several TCM components and provided a means of identifying additional anti-RA TCM. Thus, this approach may lead to the discovery of new inhibitors of chemokines or chemokine receptors that can be used to treat diseases associated with inappropriately overactive chemokine mediated inflammatory reactions.