IL-6 Induction by TNFα and IL-1β in an Osteoblast-Like Cell Line

Stress cytokines tumor necrosis factor α, interleukin-1 β and interleukin-6 modulate the activity of a variety of cell types including osteoblasts, and are involved in the pathogenesis of several rheumatic diseases associated with systemic bone loss. We have studied the expression of interleukin-6 induced by interleukin-1 β and tumor necrosis factor α in the osteoblast-like cell line MG-63, derived from a human osteosarcoma. We have observed marked differences in the regulation of interleukin-6 gene expression by tumor necrosis factor α or interleukin-1 β, at the level of mRNA steady state and stability and cytokine secretion. In addition, N-acetyl cysteine, a scavenger of reactive oxygen species, inhibits activation of NF-κB and induction of interleukin-6 by tumor necrosis factor α, being ineffective on interleukin-1 β activity. These data illustrate the action of stress cytokines on a cell line widely used in in vitro studies as a reliable model of osteoblast response to cytokines involved in bone resorbing diseases, an important issue for developing new strategies for treatments of bone diseases.