The marine factor 3,5-dihydroxy-4-methoxybenzyl alcohol prevents TNF-α-mediated impairment of mineralization in mouse osteoblastic MC3T3-E1 cells: Impact of macrophage activation.

ABSTRACT

The phenolic antioxidant 3,5-dihydroxy-4-methoxybenzyl alcohol (DHMBA), found in the Pacific oyster Crassostrea gigas, is a superior peroxyl radical scavenger compared to other materials, including Trolox. DHMBA may play an important role in the prevention of health disorders. This study elucidates whether DHMBA prevents the impairment of mineralization of mouse osteoblastic MC3T3-E1 cells under inflammatory conditions by using mouse macrophage RAW264.7 cells in vitro. Culturing with DHMBA (1-100 µM) did not affect the proliferation and death of MC3T3-E1 cells. DHMBA stimulated osteoblastic mineralization. DHMBA blocked the decrease in mineralization of MC3T3-E1 cells caused by culture with the inflammatory cytokine TNF-α. DHMBA inhibited the production of TNF-α by stimulation with lipopolysaccharide (LPS) in RAW264.7 cells. The growth of MC3T3-E1 cells was suppressed by coculture with macrophages under LPS stimulation through the crosstalk of both cells. Interestingly, the growth of MC3T3-E1 cells was suppressed by culturing with the conditioned medium obtained by culturing macrophages with LPS. The effect of the conditioned medium was blocked by the presence of DHMBA or Bay 11-7082, an inhibitor of the TNF-α pathway. The blocking effect of DHMBA was not further enhanced in the presence of Bay 11-7082. Mechanistically, DHMBA was found to decrease the levels of NF-κB p65 and the activity of NF-κB reporter expression in MC3T3-E1 cells. DHMBA was shown to prevent the impairment of osteoblastic mineralization via TNF-α signaling involved in macrophage activation in the bone marrow microenvironment. This study may provide a novel strategy for the therapy of osteoblastic impairment.