Vascular-derived reactive oxygen species for homeostasis and diseases.

Numerous basic and clinical studies have clearly identified that reactive oxygen species (ROS, i.e., H(2)O(2), O(2)(-), and ()OH) has a major role in the development of cardiovascular diseases. However, we still have no strong therapeutic strategy for clinical benefits of antioxidant administration. One potential reason for those could be a crucial role of ROS for intracellular signaling pathways that is important for vascular functions in a very low concentration. ROS contributes to the physiology and pathology of vasculature, but precise molecular regulations remain elusive. The mechanism how excessive ROS (oxidative stress) deteriorate vascular function and promote vascular diseases has not been clearly elucidated. Cyclophilin A (CyPA) has been studied as a multifunctional protein that is upregulated in a variety of inflammatory conditions, such as rheumatoid arthritis, autoimmune disease, and cancer. CyPA has been classified as an immunophilins and has a variety of intracellular functions including intracellular signaling, protein trafficking, and the regulating other proteins. Besides intracellular functions, we revealed that CyPA is a secreted molecule that has a pathological role in the cardiovascular system. CyPA has emerged as a potential biomarker and mediator of cardiovascular disease.