Activation of NF-κB in human osteoblasts by stimulators of bone resorption

Several bone resorptive stimuli affect osteoclasts indirectly by modulating the production and release of osteoblastic factors. Using electrophoretic mobility shift assays, we found that not only tumour necrosis factor-alpha (TNF-alpha) but also interleukin-1 beta and parathyroid hormone (PTH) caused dose and time-related increases in nuclear factor kappa-B (NF-kappa B)-DNA binding in Saos-2 human osteoblastic (hOB) cells. Activation of NF-kappa B by TNF-alpha was reproduced in primary hOBs. Tn contrast, consistent with their previously reported lack of response to steroid hormones, Saos-2 cells did not respond to 1,25-dihydroxyvitamin D-3. We suggest that NF-kappa B activation in osteoblastic cells constitutes an important pathway in osteoblast-mediated resorptive signalling. (C) 1999 Federation of European Biochemical Societies.