Can This Anti-Aging Drug Also Prevent Parkinsons Disease?

The FDA approved drug rapamycin has already been shown to have potent anti-aging properties, but new developments indicate it could fight Parkinson's disease too. 

There are genetic forms of Parkinson's, but the vast majority of diagnoses are thought to be caused by a complex interplay of genes and environment. Parkinson's can afflict the young, but it's overwhelmingly a disease of age. This means it's an important enemy to face down in the pursuit of healthy longevity. 

Research at the Buck Institute has now revealed that not only does rapamycin have anti-aging and anti-cancer properties, but that it may also have therapeutic benefits in Parkinson's victims. 

Familial, inherited forms of the disease arise from mutations in a protein called Parkin, encoded by the PARK2 gene in humans. These mutations hamper a cell's ability to clear out its garbage, which especially impacts on the lysosome. Lysosomes are effectively the cell's incinerator, destroying and recycling substances. In Parkinson's this failure is unique to dopaminergic neurons in a zone called the substantia nigra - where the body produces the neurotransmitter dopamine. Dopamine is involved in a huge amount of processes from pleasure to movement. 

Dysfunctional lysosomes outside the nucleus in a mouse model of Parkinson’s (left) You can see a dramatic reduction of these dysfunctional organelles following treatment with rapamycin (right) 

Credit: Almas Siddiqui, Buck Institute

A new preventative strategy

When researchers applied rapamycin to mice with the mutated Parkin protein, they found it prevented Parkinson's symptoms from arising. Rapamycin helps a process called autophagy, 'self-eating', in which the cell recycles and gets rid of damaged parts. The hope had initially been that the drug would help boost mutated Parkin's ability to label damaged proteins for removal, but it turned out rapamycin was boosting multiple processes involved with recycling, garbage clearance and particularly removing damaged mitochondria - which have also been linked to the disease. It even helped create fresh, new mitochondria.  

“This is a completely new, unrecognized, function for parkin. Our work shows that parkin plays a much broader role than was originally thought in getting rid of damaged mitochondria and proteins. It’s very exciting because it gives us new ways to look at potential therapeutics to boost cellular clean up.”

The results are exciting, but rapamycin itself is a powerful immuno-suppressant and has some fairly undesirable side effects. It may not represent a cure, but with further work, more specific derivatives and optimised dosages, it could be a big help. Current treatment for Parkinson's is woefully limited. Rapamycin is already FDA approved for other conditions, so it could speed up the pipeline a bit. 

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