Semi-vioxanthin isolated from marine-derived fungus regulates tumor necrosis factor-alpha, cluster of differentiation (CD) 80, CD86, and major histocompatibility complex class II expression in RAW264.7 cells via nuclear factor-kappaB and mitogen-activated protein kinase signaling pathways.

Semi-vioxanthin isolated from marine-derived fungus was assessed for immunoregulatory activity in mouse RAW264.7 macrophages. In the present study, the facilitative effects of semi-vioxanthin on tumor necrosis factor-alpha (TNF-alpha) and its mRNA expression and on expression of the co-stimulatory molecules, cluster of differentiation (CD) 80, CD86 and major histocompatibility complex class II (MHC II), as well as the molecular mechanism underlying the immunologic enhancement properties of semi-vioxanthin were studied. Our results clearly indicated that semi-vioxanthin treatment resulted in the degradation of IkappaB alpha, which led to the activation and nuclear translocation of the p65 subunit of nuclear factor-kappaB (NF-kappaB), as determined by immunoblotting, immunofluorescence and electrophoretic mobility shift assays (EMSA). Moreover, TNF-alpha production was prevented by NF-kappaB and mitogen-activated protein kinase (MAPK) inhibitors. Inhibition of NF-kappaB and extracellular signal regulated kinases (ERK1/2) activity by specific inhibitors blunted the effect of semi-vioxanthin on the up-regulation of CD80, CD86 and MHCII expression, but neither p38 MAPK nor c-Jun N-terminal kinase (JNK) inhibitor had this effect. Thus, we demonstrate that semi-vioxanthin regulates TNF-alpha production through NF-kappaB and MAPK signaling pathways. Activation of NF-kappaB and ERK1/2 were necessary for CD80, CD86 and MHCII expression induced by semi-vioxanthin. These data suggest that semi-vioxanthin has immunoregulatory effects.