Caution when looking at cell recycling in Parkinson’s

Researchers at the Oxford Parkinson’s Disease Centre have shown that cell recycling in Parkinson’s may play a more complex role than previously thought. These new results have been published in the journal of Cell Reports

Researchers at the Oxford Parkinson’s Disease Centre have shown that cell recycling in Parkinson’s may play a more complex role than previously thought. These new results have been published in the journal of Cell Reports.

What is cell recycling? 

Cells, including brain cells, recycle old and damaged proteins to help them remain healthy and functional. It is also thought that cell recycling is a way that cells can get rid of toxic proteins, such as alpha-synuclein, that can build up and cause problems in Parkinson’s. It has been shown that this recycling system may not be functioning properly in the condition. 

For these reasons, increasing cell recycling is one method for the development of new treatments for Parkinson’s - there is a cell recycling enhancer, nilotinib, in clinical trials for Parkinson’s

What does the new study say?

The researchers used a mouse model of Parkinson’s to look at how stopping normal recycling affected the dopamine-producing brain cells and symptoms associated with Parkinson’s. The researchers also wanted to test whether inhibiting cell recycling helped slow the accumulation of toxic alpha-synuclein. 

The team confirmed what has been seen before, that impairing cell recycling led to increased brain cell death. This supports the idea that boosting cell recycling could be protective in Parkinson’s.

However, they showed that cell recycling doesn’t impact the levels of toxic alpha-synuclein in brain cells. Suggesting more research is needed to look at how toxic proteins in Parkinson’s could be cleared from cells. 

The results also showed that, despite the fact that stopping cell recycling led to increased cell death, there was a boost in dopamine signalling which led to improved symptoms. 

So, although boosting cell recycling may be beneficial in the long term to help protect brain cells in Parkinson’s this might actually make symptoms worse by affecting dopamine signalling. The team highlighted that this should be considered in the design and interpretation of results from clinical trials, which typically rely on monitoring and measuring motor symptoms as an indicator for whether a trial is successful or not. 

Dr Katherine Fletcher, Research Communications Officer at Parkinson's UK, said: 

“This study helps us to understand more about what’s happening in brain cells in Parkinson’s and how this impacts symptoms. 

“It is essential that clinical trials are designed and assessed in the best way to ensure potential treatments for Parkinson’s don’t slip through the net. Better treatments and a cure for Parkinson’s are desperately needed for the 145,000 people living in the UK with the condition. This study highlights that care needs to be taken when measuring the success of clinical trials.” 

 

Read more about cell recycling

Read our blog to find out more about clinical trials that are looking to boost cell recycling in Parkinson's.