3 IL-17A inhibits osteoclast differentiation of RANKL-stimulated RAW264.7 cells by suppressing JNK phosphorylation and c-Fos expression

Abstract

Interleukin-17A (IL-17A) is produced by leukocytes such as Th17 cells, γδT cells, and natural killer cells. IL-17A stimulates osteoclastic bone resorption via osteoblasts by inducing the expression of the receptor activator of NF-κB ligand (RANKL). However, little is known about the direct effects of IL-17A on the osteoclast precursors. We examined the role of IL-17A on osteoclast differentiation of RAW264.7 cells. We confirmed that IL-17A and SP600125 directly inhibit differentiation of osteoclasts, which was stimulated by RANKL. We found that IL-17A reduced JNK phosphorylation and c-Fos expression, which were enhanced by RANKL stimulation. These results suggest that JNK and c-Fos are involved in the inhibition of differentiation by IL-17A stimulation.