MGH News (February 28, 2020): Case of Resistance to Autosomal Dominant Alzheimer’s Disease Suggests New Direction for Treatment

A new study at Massachusetts General Hospital reveals more information about how to prevent neuroinflammation, a response to the buildup of amyloid plaques that promote Alzheimer’s disease (AD).

Rudolph E. Tanzi, PhD, director of the Genetics and Aging Research Unit at Mass General, Ana Griciuc, PhD, neuroscientist, and colleagues sought to learn more about “crosstalk” between genes and how genetic relationships can contribute to the onset of AD.

Tanzi’s lab previously discovered the first gene associated with neuroinflammation in AD, known as CD33. In 2013, Dr. Tanzi and colleagues reported that CD33 influences the activity of microglia, sparking neuroinflammation by turning microglia from housekeepers to neuron killers.

Now Dr. Tanzi, Dr. Griciuc and colleagues have identified another gene—TREM2—which balances the influence of CD33 on microglia by shutting down microglia’s capacity to promote neuroinflammation. To study the relationship between the two genes and what occurs when one or both genes are silenced, the team studied laboratory mice specifically bred to have brain changes and behavior consistent with AD.

In AD mice that had their CD33 genes turned off, levels of amyloid plaque were reduced, and mice performed better on tests of learning and memory. When both CD33 and TREM2 were silenced, however, the mice did not show any brain or behavior benefits. Mice with only TREM2 silenced showed the same outcome. Dr. Tanzi says this tells us that TREM2 is working downstream of CD33 to control neuroinflammation.

The results of the study indicate that CD33 and TREM2 are very promising drug targets for reducing the brain nerve cell death that is caused by neuroinflammation.…