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

Cytokines, nitric oxide (NO) and reactive oxygen species (ROS) are well known for their pathogenic effects in development of cardiovascular diseases. Interleukin-1beta (IL-1beta) 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-1beta 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.