NF-kappaB as a potential therapeutic target in osteoarthritis and rheumatoid arthritis.

The family of nuclear factor-kappaB (NF-kappaB) transcription factors is intimately involved in the regulation of expression of numerous genes in the setting of the inflammatory response. Since inflammatory processes play a fundamental role in the damage of articular tissues, many in vitro and in vivo studies have examined the contribution of components of the NF-kappaB signaling pathways to the pathogenesis of various rheumatic diseases, in particular, of osteoarthritis (OA) and rheumatoid arthritis (RA). Inflammation, cartilage degradation, cell proliferation, angiogenesis and pannus formation are processes in which the role of NF-kappaB is prominent. Consequently, large efforts have been devoted to the study of the pharmacologic modulation of the NF-kappaB pathways. These studies have employed currently available therapeutic agents including non-steroidal anti-inflammatory drugs, corticosteroids, nutraceuticals and disease-modifying anti-rheumatic drugs, as well as novel small molecule inhibitors targeted to specific proteins of the NF-kappaB pathways. In addition, promising strategies such as improved antisense DNA therapy and RNA interference have been examined with encouraging results. However, since NF-kappaB also plays a crucial beneficial role in normal physiology and technical problems for effective gene therapy still remain, further research will be needed before NF-kappaB-aimed strategies become an effective therapy for joint diseases, such as OA and RA.