IL-17A suppresses the expression of bone resorption-related proteinases and osteoclast differentiation via IL-17RA or IL-17RC receptors in RAW264.7 cells

• Published in: Biochimie 2010-04, Vol.92 (4), p.398-404
• Main Authors: Kitami, Satoshi, Tanaka, Hideki, Kawato, Takayuki, Tanabe, Natsuko, Katono-Tani, Tomoko, Zhang, Fan, Suzuki, Naoto, Yonehara, Yoshiyuki, Maeno, Masao
• Format: Article
• Language: English
• Subjects: Acid Phosphatase - metabolism; Animals; Bone Resorption - genetics; Carbonic anhydrase II; Carbonic Anhydrase II - biosynthesis; Cathepsin K; Cathepsin K - biosynthesis; Cell Differentiation - drug effects; Cell Line; Gene Expression - drug effects; Interleukin-17; Interleukin-17 - genetics; Interleukin-17 - physiology; Isoenzymes - metabolism; Matrix Metalloproteinase 9 - biosynthesis; Matrix metalloproteinase-9; Mice; Osteoclast precursors; Osteoclasts - cytology; Osteoclasts - physiology; Receptor Activator of Nuclear Factor-kappa B - biosynthesis; Receptor, Macrophage Colony-Stimulating Factor - biosynthesis; Receptors, Interleukin-17 - biosynthesis; Receptors, Interleukin-17 - physiology; RNA, Messenger - metabolism; Tartrate-Resistant Acid Phosphatase
• ISSN: 0300-9084; 1638-6183
• DOI: 10.1016/j.biochi.2009.12.011

Interleukin-17 (IL-17) is produced exclusively by activated T cells and neutrophils, and stimulates osteoclastic bone resorption via osteoblasts by inducing the expression of “receptor activator of NF-κB (RANK) ligand” (RANKL). However, the direct effects of IL-17 on the differentiation of osteoclast precursors into osteoclasts and on the function of osteoclasts have not been clarified. Therefore, we examined the effects of IL-17A on the differentiation of osteoclast precursors using RAW264.7 cells and also on the expression of carbonic anhydrase II (CA II), cathepsin K, matrix metalloproteinases-9 (MMP-9), RANK, c-fms, and IL-17 receptors in these cells. The cells were cultured with or without 0.1, 1.0, 10 or 50 ng/mL IL-17 in the presence of soluble RANKL for up to 10 days. The CA II, cathepsin K, and MMP-9 mRNA and protein expression levels were examined using real-time PCR and Western blotting, respectively. The mRNA expression levels of RANK, c-fms, and IL-17 receptors were monitored by real-time PCR. Osteoclast differentiation was estimated using tartrate-resistant acid phosphatase (TRAP) staining of the cells. TRAP-positive cells were observed after day 5 of culture, and the number of cells decreased in the presence of 10 and 50 ng/mL IL-17A at days 5 and 7. In the presence of IL-17A, the expressions of cathepsin K, MMP-9 and c-fms decreased markedly on days 5 and/or 7 of culture, whereas the expression of CA II and IL-17 receptor (type A) increased remarkably at days 3 and 7, respectively. The expression of RANK and IL-17 receptor (type C) was not affected by the addition of IL-17A. These results suggest that the differentiation of osteoclast precursors into osteoclasts is suppressed at high concentrations of IL-17A. Furthermore, IL-17A suppresses the hydrolysis of matrix proteins during bone resorption by decreasing the production of cathepsin K and MMP-9 in osteoclasts.