The Marine Factor 3,5-dihydroxy-4-methoxybenzyl Alcohol Suppresses Cell Growth, Inflammatory Cytokine Production, and NF-κB Signaling-enhanced Osteoclastogenesis in In Vitro Mouse Macrophages RAW264.7 Cells

Abstract

Background and objective: The novel marine factor 3,5-dihydroxy-4-methoxybenzyl alcohol (DHMBA) was originally identified in the Pacific oyster Crassostrea Gigas. DHMBA has been shown to prevent oxidative stress by scavenging radicals and enhance the production of antioxidant proteins. However, the pharmacologic role of DHMBA has been poorly understood. Inflammation is implicated in the pathogenesis of many diseases. Inflammatory cytokines are produced in macrophages with stimulation of lipopolysaccharide (LPS) and are used as biomarkers that cause diverse disease conditions. Therefore, this study has been undertaken to elucidate whether DHMBA expresses anti-inflammatory effects in in vitro mouse macrophage RAW264.7 cells. Methods: Mouse macrophage RAW264.7 cells were cultured in a medium containing 10% fetal bovine serum (FBS) with or without DHMBA (1-1000 µM). Results: Culturing with DHMBA (1-1000 µM) suppressed the growth and stimulated the death of RAW264.7 cells in vitro, leading to a decrease in cell number. Treatment with DHMBA reduced the levels of Ras, PI3K, Akt, MAPK, phospho-MAPK, and mTOR, which are signalling factors to promote cell proliferation, and it raised the levels of p53, p21, Rb, and regucalcin, which are cell growth suppressors. DHMBA treatment elevated caspase-3 and cleaved caspase-3 levels. Interestingly, DHMBA treatment repressed the production of inflammatory cytokines, including tumor necrosis factor-α, interleukin-6, interleukin-1β, or prostaglandin E2, which were enhanced by LPS stimulation. Notably, the levels of NF-κB p65 increased by LPS treatment, and this augmentation was repressed by DHMBA treatment. Moreover, LPS treatment stimulated osteoclastogenesis of RAW264.7 cells. This stimulation was blocked by DHMBA treatment, and this effect was not caused by the presence of an NF-κB signalling inhibitor. Conclusion: DHMBA was found to potentially suppress the activity of inflammatory macrophages in vitro, suggesting its therapeutic usefulness in inflammatory conditions.