Mass. General study finds protective gene variant promotes clearance of toxic amyloid beta protein from the brain
Massachusetts General Hospital (MGH) investigators have determined that one of the recently identified genes contributing to the risk of late-onset Alzheimer's disease regulates the clearance of the toxic amyloid beta (A-beta) protein that accumulates in the brains of patients with the disease. In their report receiving advance online publication in Neuron, the researchers describe a protective variant of the CD33 gene that promotes clearance of A-beta from the brain. They also show that reducing expression of CD33 in immune cells called microglia enhances their ability to clear away A-beta protein, raising the possibility that blocking CD33 activity could help the brain's immune system remove A-beta.
"Our findings show, for the first time, a "switch" that controls how fast microglial cells can clear A-beta protein from the brain as we age – CD33 is the key," says Rudolph Tanzi, PhD, director of the Genetics and Aging Unit in the MGH Department of Neurology and senior author of the Neuron paper. "If we can find a way of safely inactivating CD33 on microglia, we should be able to slow the accumulation of A-beta in aging brains and hopefully reduce risk for Alzheimer's disease."
In 2008, as part of the Alzheimer's Genome Project, Tanzi's team identified four novel genes containing variants that increased the risk of late-onset Alzheimer's, the most common form of the devastating neurological disorder. One of these was CD33. The protein was known to play a role in regulation of the innate immune system – the body's first line of defense against infection – but how it might function in the brain and possibly contribute to Alzheimer's risk was not known.
In the current study, the researchers first found that CD33 activity was significantly higher in microglia cells in brain samples from Alzh
Simonig, I doubt tackling CD33 alone would do the job, but as Tanzi has always said, they will find the genes and then drugs can be found to negate the effects of the bad genes. Last I heard he did not advocate trying to change the genes. If CD33 can increase clearance, for instance further down the track a drug targeting CD33 could be used as an adjuvant to make drugs like PBT2 more effective.
I imagine the antisense technology companies like ISIS and Idera will be more interested in that snippet right now with the ability in the works to intercept the RNA messenger from various genes to the cell.
15 years from now an effective CD33 RNA drug could show up in Prana's prodromal treatment space and erode some of Prana's $30B market cap:-)
His work is pertinent in general because he is a member of Prana's R & D advisory board as listed below. He has been a key speaker and proponent of the promise PBT2 holds in fighting neuro-degenerative diseases. His work could also lead Prana in their pursuit of other drugs or compounds, whether within our existing MPAC library or even in new directions.
Prana's scientific advisory board:
Dr. Jeffrey L.Cummings (Chairman) - Cleveland Clinic's Lou Ruvo Center for Brain Health
Dr. Craig W.Ritchie - Imperial College London
Dr. Steven D. Targum - Oxford Bioscience Partners **
Professor Jean-Marc Orgogozo - University of Bordeaux
Professor Rudolph Tanzi - Harvard Medical School, Massachusetts General Hospital
Professor Colin Masters - The University of Melbourne