Interleukin-17A induces cathepsin K and MMP-9 expression in osteoclasts via celecoxib-blocked prostaglandin E2 in osteoblasts

• Published in: Biochimie 2011-02, Vol.93 (2), p.296-305
• Main Authors: Zhang, Fan, Tanaka, Hideki, Kawato, Takayuki, Kitami, Satoshi, Nakai, Kumiko, Motohashi, Masafumi, Suzuki, Naoto, Wang, Chun-Ling, Ochiai, Kuniyasu, Isokawa, Keitaro, Maeno, Masao
• Format: Article
• Language: English
• Subjects: 3T3 Cells; Acid Phosphatase - metabolism; Animals; Bone Resorption - metabolism; Carbonic Anhydrase II - genetics; Carbonic Anhydrase II - metabolism; Cathepsin K - genetics; Cathepsin K - metabolism; Celecoxib; Cell Differentiation - drug effects; Cyclooxygenase 2 - deficiency; Cyclooxygenase 2 - genetics; Cyclooxygenase 2 - metabolism; Cyclooxygenase 2 Inhibitors - pharmacology; Dinoprostone - biosynthesis; Gene Expression Regulation, Enzymologic - drug effects; Gene Silencing; Interleukin-17 - pharmacology; Isoenzymes - metabolism; Matrix Metalloproteinase 9 - genetics; Matrix Metalloproteinase 9 - metabolism; Mice; Osteoblasts - drug effects; Osteoblasts - metabolism; Osteoclasts - cytology; Osteoclasts - drug effects; Osteoclasts - metabolism; Pyrazoles - pharmacology; RANK Ligand - metabolism; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA, Small Interfering - genetics; Sulfonamides - pharmacology; Tartrate-Resistant Acid Phosphatase
• ISSN: 0300-9084; 1638-6183
• DOI: 10.1016/j.biochi.2010.10.001

Interleukin-17 (IL-17) is a cytokine secreted primarily by T(H)-17 cells that can stimulate the development of osteoclasts (osteoclastogenesis) in the presence of osteoblasts. IL-17, through osteoblasts, has indirect effects on the expression of bone resorption-related enzymes in osteoclasts, which have not been well clarified. Here, using MC3T3-E1 cells and RAW264.7 cells as osteoblasts and osteoclast precursors, we aimed to clarify these effects of IL-17A. MC3T3-E1 cells were cultured in the presence or absence of IL-17A for 72 h and the conditioned media collected (in the presence of soluble receptor activator of NF-кB ligand) and used to culture RAW264.7 cells. To assess osteoclast differentiation, adherent cells were fixed and stained for tartrate-resistant acid phosphatase (TRAP). Our analyses demonstrated that the number of TRAP-positive multinucleated cells increases after 3 days of culture in conditioned medium from IL-17A-treated cells compared to untreated controls. In addition, we observed that the levels of cathepsin K and MMP-9 increase in the conditioned medium from IL-17A-treated cells, whereas CA II expression levels remain unaffected. PGE(2) production from MC3T3-E1 cells increased in the presence of IL-17A. Celecoxib, a specific inhibitor of cyclooxygenase-2 (COX-2), blocked both the IL-17A-stimulated increase in TRAP-positive multinucleated cells and the expression of cathepsin K and MMP-9. Furthermore, when MC3T3-E1 cells were transformed with small interfering RNA to silence COX-2 expression before IL-17A treatment, the resulting conditioned medium was less effective at inducing cathepsin K and MMP-9 expression in RAW264.7 cells. These results suggest that IL-17A induces the differentiation and function of osteoclasts via celecoxib-blocked prostaglandin, mainly PGE(2), in osteoblasts.