Copper Transport Protein Antioxidant-1 Promotes Inflammatory Neovascularization via Chaperone and Transcription Factor Function

The challenge in scientific investigation is twofold. One must figure out first what is going on, and then, perhaps more importantly, how it is happening. Answering these two questions provides valuable insight into how certain phenomena occur, and this can help in learning about new fields and advancing the overall knowledge about a certain topic. In human biology, for example, it is well-known that Copper (Cu) plays a very important role in a number of processes, and that the levels in which it exists in the body can affect a wide range of conditions. For example, it plays a key role in physiological repair processes such as wound healing and angiogenesis. However, it is also known to play a role in tumor growth and inflammatory diseases such as atherosclerosis. Additionally, Cu cells have been shown to induce neovascularization and increased concentrations can be found in angiogenic tissue. Cu chelators have been shown to treat Wilson disease, as well as inhibit tumor growth and angiogenic responses. Cu chelation has also demonstrated effectiveness in the treatment of solid tumors, resulting in the diseases' stabilization. However, while all of these processes and reactions are attributed to Cu in some way, little is known about the molecular mechanisms that make these happen. Researchers know the "what," but they don't yet know the "how."

This was the focus of the study conducted by Chen et al. from the University of Illinois Departments of Medicine. Specifically, they wanted to know the role of Cu transport protein Antioxidant-1 (Atox1) in ischemia-induced neovascularization, a processes dependent on angiogenesis/arteriogenesis, inflammation, and reactive oxygen species (ROS). To perform this study, Chen's research team needed to measure a variety of different factors, including lysyl oxidase (LOX) activity, largely because this has a role in increasing or decreasing angiogenesis through the regulation of the extracellular matrix. To measure LOX activity, the research team used the Amplite Fluorimetric Lysyl Oxidase Assay Kit. By using a proprietary LOX substrate that releases hydrogen peroxide upon LOX oxidation, this kit offers a sensitive fluorescent assay to measure LOX activity. The hydrogen peroxide released is detected using Amplite's HRP substrate, which allows for the detection of sub ng/ml LOX, making it much more sensitive than other fluorometric assays for this enzyme activity.

In the end, Chen's team found that Atox 1 plays an essential role in inflammatory neovascularization to help recruit inflammatory cells which secrete TNFα and VEGF via the p47phox/ROS-NFkB-ICAM-1/VCAM-1 pathway. This understanding of the role of Atox1 will help lay out a path for new therapeutic strategies for inflammation-dependent ischemic cardiovascular diseases. Part of the reason this research group was able to better understand the role Cu plays in these biological processes was through their measurement of LOX activity. Because they used the Amplite Fluorimetric Lysyl Oxidase Assay Kit, they were able to accurately measure LOX activity and therefore verify the relationship between Atox1, Cu and the extracellular matrix. These researchers made a big step forward in understanding the "how" so that the field as a whole can continue to advance.

References

---

1. Chen, Gin-Fu, et al. "Copper transport protein antioxidant-1 promotes inflammatory neovascularization via chaperone and transcription factor function." Scientific reports 5 (2015): srep14780.