Interleukin-1 and nitric oxide increase NADPH oxidase activity in human coronary artery smooth muscle cells

ABSTRACT

Cytokines, nitric oxide [NO] and reactive oxygen species [ROS] are well known for their pathogenic effects in development of cardiovascular diseases. Interleukin-1 [IL-1] is known to induce NO generation, however it is not well established if IL-1beta or NO regulate production of ROS, such as superoxide anion. Therefore, the main objective of this study was to evaluate the effect of IL-1beta or NO on enzyme activity of NADPH oxidase [NOX], a superoxide-generating system recently documented to participate in a variety of vascular functions. Human coronary artery smooth muscle cells [SMC] obtained from Clonetics were treated with IL-1 beta and NO donor, sodium nitroprusside [SNP], in culture. Nitrites accumulated in supernatants of SMC cultures were measured as an index of NO released following treatment with IL-1beta. NOX enzyme activity was assayed using cytochrome c as the electron acceptor. Treatment with IL-1beta resulted in a 3-fold increase in the production of NO by SMC. Both IL-1beta and SNP enhanced NOX activity, by 67 and 45%, respectively, following 24 h of treatment. This study suggests that NO or NO- generating cytokines might regulate the production of ROS in the cardiovascular system through modulation of superoxide-generating systems such as NOX