Ethanol activates the interleukin-6 promoter in a human bone marrow stromal cell line

Chronic ethanol consumption is associated with the development of osteoporosis. The pro-inflammatory cytokine interleukin-6 (IL-6) plays a role in the development of osteoporosis through stimulation of osteoclastic activity. We hypothesized that ethanol promotes osteoporosis, in part, by increasing IL-6 production in the bone microenvironment. Accordingly, we evaluated ethanol's effect on IL-6 production in the Saka human bone marrow stromal cell line and in the HOBIT human osteoblast-like cell line. We found that ethanol increased IL-6 protein levels in the culture supernatants from Saka, but not HOBIT, cells. In addition, we observed that ethanol increased steady-state IL-6 mRNA levels and activated an IL-6 promoter-driven reporter vector in Saka cells. We conclude that ethanol stimulates IL-6 expression in the Saka bone marrow stromal cell line by enhancing transcriptional activity of the IL-6 gene. Our findings support the contention that ethanol may contribute to the pathogenesis of osteoporosis, in part, by increasing IL-6 expression in the bone microenvironment.