Neuroglobin

Contributed by: Michael Rafii, M.D., Ph.D - Director of the Memory Disorders Clinic at the University of California, San Diego.
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Neuroglobin is a protein that was first identified in 2000. It is a member of the globin family, similar to hemoglobin (which carries oxygen inside red blood cells) and myoglobin (which carries oxygen inside muscle cells). It is a highly conserved protein, meaning that it is a very important protein in all species, ranging from mice to humans. It is known to be activated by cerebral ischemia (decreased brain oxygen) and is known to protect neurons from such injury.

Despite its ability to bind to oxygen, like hemoglobin and myoglobin, neuroglobin is unlikely to function as an oxygen delivery system. Instead, it seems to be involved in scavenging reactive oxygen molecules (oxidants) generated in response to brain ischemia and injury. Many researchers believe antioxidants are beneficial in various neurodegenerative diseases.

Recent work had shown that neuroglobin decreases beta amyloid neurotoxicity in animal models of AD. Now, a paper from a group at Johns Hopkins (Zymanski et al, Neurobiology of Aging, 2009), shows that variations in the gene for the neuroglobin protein, may in fact increase one's risk of developing AD, by producing inefficient neuroglobin. This inefficient protein is unable to defend against the toxicity of beta amyloid.

More work will be needed to determine if neuroglobin can be affected in a positive way to reduce beta amyloid toxicity in AD patients.