The effect of ethanol and N-nitrosodimethylamine on the iNOS-dependent NO production in human neutrophils. Role of NF-κB.

1. The objective of study was to determine the influence of ethanol and/or N-nitrosodimethyloamine (NDMA) on the inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production by human neutrophils and determination of the role of NF-κB in this process. 2. Isolated polymorphonuclear leukocytes (PMNs) derived from 15 human volunteers were incubated in the presence of ethanol and/or NDMA. Expression of the tested proteins were evaluated using the Western blot method. Total NO metabolites was assayed in the cell cultures by Griess reaction. 3. In neutrophils exposed to ethanol or NDMA was observed an increased NF-κB-dependent NO production mediated by iNOS with the contribution of MAP kinases: p38 and JNK. An inhibiting effect of NF-κB signaling pathway on the MAP kinases was observed, which are involved in the iNOS-dependent NO production. By the simultaneous effect, ethanol and NDMA caused stronger generation of NO by neutrophils without the contribution of iNOS. Inhibition of NF-κB in cells simultaneously exposed to the xenobiotics caused a decreased expression of MAP kinases. 4. Individual and simultaneous effect of ethanol and NDMA may cause disorders in the response of immune system. However, the joint effect of the tested substances results in uncontrolled interactions, leading to cascading disorders of signal transduction.