Selective inhibition of NF-kappa B blocks osteoclastogenesis and prevents inflammatory bone destruction in vivo.

Bone destruction is a pathological hallmark of several chronic inflammatory diseases, including rheumatoid arthritis and periodontitis. Inflammation-induced bone loss of this sort results from elevated numbers of bone-resorbing osteoclasts. Gene targeting studies have shown that the transcription factor nuclear factor-kappa B (NF-kappa B) has a crucial role in osteoclast differentiation, and blocking NF-kappa B is a potential strategy for preventing inflammatory bone resorption. We tested this approach using a cell-permeable peptide inhibitor of the I kappa B-kinase complex, a crucial component of signal transduction pathways to NF-kappa B. The peptide inhibited RANKL-stimulated NF-kappa B activation and osteoclastogenesis both in vitro and in vivo. In addition, this peptide significantly reduced the severity of collagen-induced arthritis in mice by reducing levels of tumor necrosis factor-alpha and interleukin-1 beta, abrogating joint swelling and reducing destruction of bone and cartilage. Therefore, selective inhibition of NF-kappa B activation offers an effective therapeutic approach for inhibiting chronic inflammatory diseases involving bone resorption.

Subcutaneous injections of a TNF-alpha antagonistic peptide inhibit both inflammation and bone resorption in collagen-induced murine arthritis.

The cyclic peptide WP9QY (YCWSQYLCY), which was designed to mimic the most critical tumor necrosis factor (TNF) alpha recognition loop on type1 TNF receptor, antagonizes the effects of TNFalpha. In this study, we investigated the effects of WP9QY peptide on collagen-induced arthritis (CIA) mice to evaluate its effects on inflammatory bone destruction. DBA/1J mice were injected intradermally at the base of the tail with bovine type II collagen, emulsified in complete Freund's adjuvant on day 0 and 21. The three sets of WP9QY peptide injections (24 mg/kg x 8 times per day) were performed before the onset of paw swelling. Mice were sacrificed at day 38 and thereafter, the arthritis scores as well as radiographical and histological outcomes were assessed. WP9QY peptide inhibited CIA-induced increase in the arthritis score. Furthermore, histomorphometric analysis of the tibial epiphysis region revealed that WP9QY peptide inhibited the increase of synovial pannus infiltration and the decrease of bone volume, which were induced by the CIA. The WP9QY treatment prevented the inflammation as well as bone destruction of the joints in the CIA mice, suggesting that the administration of WP9QY peptide might be useful for developing a drug to prevent inflammatory bone destruction.

A tumor necrosis factor receptor loop peptide mimic inhibits bone destruction to the same extent as anti-tumor necrosis factor monoclonal antibody in murine collagen-induced arthritis.

OBJECTIVE: The cyclic peptide WP9QY (YCWSQYLCY) was designed to mimic the most critical tumor necrosis factor alpha (TNFalpha) recognition loop on TNF receptor I, and it prevents interactions of TNFalpha with its receptor. We undertook this study to compare the effects of the WP9QY peptide on collagen-induced arthritis (CIA) in mice with those of anti-TNFalpha monoclonal antibody. METHODS: CIA was induced by primary and secondary immunizations. Osmotic minipumps were implanted in the backs of all mice on the day of the booster injection (day 21), and vehicle, anti-TNF antibody (4 mg/kg/day), or WP9QY peptide (2 mg/kg/day or 4 mg/kg/day) was continuously infused until the mice were killed (day 40). Thereafter, clinical, radiographic, and histologic assessments were performed. RESULTS: WP9QY treatment inhibited CIA-induced increases in the arthritis score, but onset of disease was not delayed by the peptide. The inhibitory effect of WP9QY on inflammation was definitely weaker than that of anti-TNF antibody. Microfocal computed tomography analyses, however, revealed that WP9QY blocked CIA-induced bone destruction at the knee joints to the same extent as did anti-TNF antibody. In addition, WP9QY inhibited synovial pannus infiltration and reduced osteoclast number. Furthermore, inhibition of CIA-induced systemic bone loss by WP9QY was more apparent than that by anti-TNF antibody. CONCLUSION: The TNFalpha antagonist WP9QY would be a useful template for the development of small molecular inhibitors to prevent both inflammatory bone destruction and systemic bone loss in rheumatoid arthritis.