The discovery of a chemical capable of preventing neuronal death in conditions including Alzheimer’s Disease, Parkinson’s Disease and Huntingdon’s Disease, is being hailed as a ‘turning point’ in the fight against these conditions.
Alzheimer’s, Parkinson’s and Huntingdon’s are all neurodegenerative disorders, which means that they all involve the progressive death of cells in the brain. In Alzheimer’s, this cell death causes a characteristic loss of memory, while in Parkinson’s it is control of movement that is most affected. The cause is largely the same though – death of cells in the brain. It is the location of the cell loss that determines the symptoms.
This neurodegeneration usually occurs as a result of one of the body’s own defence systems backfiring. When viruses infect a cell, they cause it to pump out viral proteins that aid the spread of the virus. In order to prevent this, the cells are programmed to shut off protein production if an incorrect protein is created. This is undeniably beneficial when fighting viruses, but not so good if the cell malfunctions of its own accord by producing a broken (‘misfolded’) protein.
Proteins ‘fold’ after creation into a shape that defines them. Sometimes though, this folding goes awry and you end up something else: a ‘misfolded’ protein. These misfolded proteins bring about the same response a viral protein would, shutting down the cell that created it. Unfortunately, this serves to starve the cell of vital proteins integral to its function and survival, and eventually kills it. In neurodegenerative diseases, misfolded proteins hang around, starving cells around them and giving us the spreading cell death that is at the heart of Alzheimer’s.
Scientists have been working for decades in the hope of finding a way of interrupting this process, and now researchers based at the University of Leicester have discovered a chemical that appears to do just that.
The chemical in question works by inhibiting an enzyme known as PERK. This enzyme plays a part in the process of shutting down a cell in response to misfolded proteins. It has been found that by inhibiting it, we can prevent the response altogether, keeping cells alive long after they would otherwise have perished.
Clearly, this discovery is a great step forward. Perhaps the most exciting aspect of it all is that it seems to work on a wide range of neurodegenerative disorders, despite the fact that different proteins are misfolded in each one. Professor Roger Morris of King’s College London is quoted as saying “This finding, I suspect, will be judged by history as a turning point in the search for medicines to control and prevent Alzheimer’s disease,” but this is actually underplaying it a little; the potential of this chemical reaches far beyond Alzheimer’s.
That said, there is a long way to go before we have something we can give ourselves to stave off dementia. For a start, there were some significant side effects in the mice that were tested, not least that they developed diabetes as a result of action of the chemical in the pancreas. Any drug would have to only work on the brain to be considered for use. Additionally, a mouse brain is far less complex than one of ours; there is no guarantee that the same approach will work in humans. For now though, we can celebrate this major advance in medicine. As Professor Morris said, “The world won’t change tomorrow, but this is a landmark study.”