Peptide developed that may slow Parkinson's disease

A new research suggests it may be possible to slow the progression of Parkinson's disease using a man-made peptide that stops the formation of faulty protein fibrils that kill the brain cells that produce dopamine.

Parkinson's is caused by the loss of dopamine cells in the brain.

Estimates suggest up to 10 million people worldwide are living with Parkinson's disease - a progressive neurological disorder caused by the loss of brain cells that release dopamine, a chemical that is important for conveying messages that control movement.

The main reason behind the death of dopamine-producing cells in patients with Parkinson's disease is thought to be a fault in a common cell protein called α-synuclein. 

When faulty, the protein forms the wrong shape and clumps into long toxic fibrils that stop the cells functioning properly.

As Parkinson's disease progresses, the symptoms - which include tremor, stiffness, slowness and impaired balance - gradually worsen and patients find it increasingly difficult to walk, talk and take care of themselves.

While one or two early-stage studies are showing promising results, there is currently no cure for Parkinson's disease, although there are drugs that can bring dramatic relief from symptoms.

Now, a new study - funded by Parkinson's UK and led by the University of Bath in the UK - shows how a peptide they designed may offer a way to slow the progression of Parkinson's disease.

A peptide is a chain of amino acids. A chain of several peptides is a protein.

In this study, the researchers found that their peptide sticks to misshapen α- synuclein and stops it stacking into the fibrils that kill off the dopamine cells.

The peptide matches a region of α-synuclein that is mutated in Parkinson's

To make their peptide - which comprises 10 amino acids - the team searched a library of peptides for candidates that match the region of α-synuclein that is mutated in patients with early-onset Parkinson's.

The research team at the Department of Biology & Biochemistry at Bath, explains how their peptide works:

"If you think of the misshapen α-synuclein proteins as Lego bricks which stack to form a tower; our peptide acts like a smooth brick that sticks to the α-synuclein and stops the tower from growing any bigger."

The researchers believe their study is the first to look at this part of α-synuclein as a potential drug target.

The researchers say their work is still in the early stages, but they are encouraged by the results they have achieved so far. They hope their study heralds a new approach to the treatment of Parkinson's disease.

The researchers now plan to test the peptide in mammal brain cells and then start the process of developing it into a drug that can be used in humans.

In their paper, the team notes that the technique may also apply to other neurodegenerative diseases like Alzheimer's disease, which also arises as a result of misshapen proteins clumping together in the brain.

References:

1.  Intracellular screening of a peptide library to derive a potent peptide inhibitor of α-synuclein aggregation, Harish Cheruvara, et al., J. Biol. Chem., doi:10.1074/jbc.M114.620484, published online 23 January 2015, abstract.
2.  Parkinson's UK news release, accessed 26 February 2015 via EurekAlert.