Parkinson’s disease is a neurodegenerative condition. It is caused by the loss of nerve cells in a region of the brain called the substantia nigra – it is not known yet what causes this exactly, but scientists speculate that it is a combination of genetic and environmental factors. The nerve cells are responsible for producing dopamine, which acts as a chemical messenger between the parts of the brain and nervous system dealing with body movements and coordination; so, the loss of these nerve cells leads to a decrease in dopamine levels, resulting in slow and abnormal movements. This is a slow process – the symptoms of Parkinson’s only start to develop after about 80% of the nerve cells in the substantia nigra have been lost. The main symptoms are:
- Tremor – shaking that begins in the hand/arm (usually when the limb is resting or relaxed)
- Slowness of movement (bradykinesia) – physical movements slow down, making everyday tasks much more difficult and also possibly resulting in a slow, shuffling walk
- Stiffness of muscle (rigidity) – muscle tension, which can make movement and facial expressions painful, as well as muscle cramps (dystonia)
Currently, the treatments for Parkinson’s are supportive therapy, medication and surgery in some cases; that is until scientists found a molecule that could stop and possibly even reverse the neural degeneration.
The development of Parkinson’s has been associated with certain toxic mechanisms that establish in the brain. One of the main mechanisms is the formation of aggregates, called ‘Lewy bodies’ – these disrupt the activity of nerve cells. They are made out of a protein called alpha-synuclein (it is still unclear how this protein is produced and the exact role it plays in the brain). However, it is understood that acting on this protein could put a stop to the neural damage.
A team of researchers from the Universitat Autònoma de Barcelona in Spain scanned and analysed the properties of over 14,000 potential molecules and eventually identified Synu-Clean D, which acts as an inhibitor for aggregation. They tested it in vitro (lit. in glass), to see if it would be effective in human cell cultures, and it was. The researchers then moved on to testing the molecule in vivo (lit. in the living) – in particular the Caenorhabditis elegans worm (C. elegans), which has a much simpler neuron circuitry than humans and also expresses alpha-synuclein in muscle and certain nerve cells such as dopaminergic neurons (which are key in synthesising dopamine). In this test, the scientists administered the molecule to the worms in food, and found that it stopped the protein from attaching; it added protection from neural degeneration and increased mobility as well.
The researchers hope that their findings will help to develop targeted treatments for Parkinson’s as well as other neurodegenerative conditions.
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