Blocking key enzyme may reverse memory loss

CAMBRIDGE, Mass.— Massachusetts Institute of Technology (MIT) researchers say they have now shown that they can reverse memory loss in mice by interfering with the enzyme that forms the blockade. The enzyme, known as HDAC2, turns genes off by condensing them so tightly that they can’t be expressed.

For several years, scientists and pharmaceutical companies have been trying to develop drugs that block this enzyme, but most of these drugs also block other members of the HDAC family, which can lead to toxic side effects. The MIT team has now found a way to precisely target HDAC2, by blocking its interaction with a binding partner called Sp3.

“This is exciting because for the first time we have found a specific mechanism by which HDAC2 regulates synaptic gene expression,” says Li-Huei Tsai, director of MIT’s Picower Institute for Learning and Memory and the study’s senior author.

Blocking that mechanism could offer a new way to treat memory loss in Alzheimer’s patients. In this study, the researchers used a large protein fragment to interfere with HDAC2, but they plan to seek smaller molecules that would be easier to deploy as drugs.

The protein fragment that the researchers used to block the interaction in this study has about 90 amino acids, which would likely be too large to use as a drug, so the researchers hope to either identify a smaller segment that would still be effective, or find a chemical compound that would also disrupt the Sp3-HDAC2 interaction.

Tsai also hopes to further investigate some of the other genes that were found to correlate with HDAC2, in hopes of identifying other drug targets. She also plans to explore whether this approach could be useful in treating other disorders that involve elevated levels of HDAC2, such as post-traumatic stress disorder.