Douglas G. Walker, Ph.D.
Sun Health Research Institute
Sun City, Arizona

2006 Investigator-Initiated Research Grant

Inflammation may be a significant cause of damage occurring in the brain of people with Alzheimer's disease. However, nerve cells have specialized mechanisms intended to provide some protection against inflammation. One of these mechanisms is the protein CD200, which is found on the surface of many nerve cells.

CD200 is recognized by the CD200 receptor, a "docking site" found on the surface of immune system cells that promote inflammation. Binding of CD200 to its receptor can reduce the signals leading to inflammation, thereby preventing damage to healthy nerve cells.

Douglas Walker, Ph.D., and colleagues have found that nerve cells from the brains of persons with Alzheimer's disease, as well as other brain diseases, have reduced levels of CD200. This alteration could make nerve cells in these patients more vulnerable to attack during inflammatory events. This phenom-enon may explain the observation that Alzheimer-diseased brain tissue often appears to be in a state of constant inflammation.

The researchers plan to continue their studies of the CD200 signaling system in cell cultures to understand further how it regulates inflammation. They are planning to test in cell cultures the idea that increasing the expression of CD200 can reduce the inflammatory response in brain tissue.