Mycotoxin fumonisin B1 stimulates nitric oxide production in a murine macrophage cell line

Fumonisin B1 (FB1), a mycotoxin, is a common fungal contaminant of corn and corn products. This sphingolipid-like compound causes a variety of animal diseases and is a suspected human carcinogen. Cellular targets of FB1 include hepatocytes and renal and immune cells. The effects of FB1 on nitric oxide (NO) production induced by lipopolysaccharide (LPS) were investigated in the present study by using a murine macrophage cell line as a model system. Stimulation of NO production was observed for increasing concentrations of FB1 (1, 10, and 100 microM) and either 0.005 or 0.01 microgram/ml LPS. Although with an increasing dose of FB1 the total protein content decreased for the stimulated and the unstimulated cells, the NO production remained elevated for the stimulated cells. It can be hypothesized that the potentiation of the LPS-dependent NO production by FB1 treatment could be due to direct interaction between FB1 and NO synthases and LPS receptors or to a disrupted sphingolipid metabolism.