Now where were those keys?

This week sees the news of an important breakthrough in the study of degenerative brain diseases such as Alzheimer's and Parkinson's diseases.While it has been known that the diseases spread due to the spread of a distorted protein, (the tau protein for Alzheimer's ), outward from an area where memories are made and stored, the mechanism of spread was not clear. There were two possible mechanisms proposed for the spread. One, that the spread could take place from neuron to neuron, along neuronal pathways, and the other that there were neighbourhoods that were susceptible to the bad protein, and others that could resist it. It is now established that the spread takes place along neuronal pathways.

The experiments that establish this mechanism are ingenious, and involve genetically engineered mice that can create the human tau protein in a localised area called the entorhinal cortex. Cells in the entorhinal cortex of the mice started dying due to the tau protein. In due course, the disease spread to other areas via the neuronal network. Since other cells could not make the tau protein themselves, the only way the tau could show up in other areas was via transmission from nerve cell to nerve cell. It may then be possible to halt the diseases by preventing cell to cell transmission, e.g. by blocking the tau with an antibody. This might provide the key to the prevention of degenerative nerve diseases (and help find those elusive keys!).

This blog post is by Neelima Gupte and Sumathi Rao.