This project aims to demonstrate the use of a new in vitro technique which avoids the use of animals to screen a library of drugs approved for a range of diseases to test whether they might also be effective treatments for Parkinson's disease.
Parkinson's disease is a neurodegenerative disease, without cure, which affects one person in every 500. Current treatments can only relieve symptoms, and do not stop the disease progressing. The aggregation of a protein called alpha synuclein is thought to have a role in the development of Parkinson's disease, so a way of testing which drugs can prevent this aggregation could lead to the development of more efficacious treatments.
Research details and methods
Drug libraries containing compounds already approved for use in other disease areas will be screened for their action against alpha synuclein using an alpha synuclein protein misfolding cyclic amplification system, published by Herva in 2014.
The use of libraries of approved drugs means that all of the safety studies that require animal testing have already been done. After selecting the drugs that inhibit alpha synuclein aggregation, their efficacy and biological relevance will be assessed using existing and new cellular and mouse models of Parkinson's disease.
This project will improve the knowledge about the mechanisms of alpha synuclein aggregation and accumulation in Parkinson's disease. It could produce results that could translate into disease modifying therapies slowing down or even stopping the progression of Parkinson's disease with minimal animal use.
Parkinson's disease is a brain disorder characterised by aggregated alpha synuclein (a-syn) inside intraneuronal inclusions known as Lewy bodies.
We studied if protein misfolding cyclic amplification (PMCA), used to replicate prion protein aggregates could be used to grow a-syn aggregates. Briefly, proteins are subjected to cycles of sonication and incubation and fibril formation is monitored by increased Thioflavin T fluorescence.
Our electron microscopy, circular dichroism and native gels results indicate that stable a-syn fibrils were formed. We also tested the a-syn anti-aggregation activity of several drugs and the results suggest that the a-syn PMCA is robust system for anti-aggregating drug screening. So we propose to use previously approved drugs, with animal testing already done, to repurpose into the treatment for Parkinson disease using the a-syn PMCA.
The proposal has two aims: first, drug screening by high throughput a-syn PMCA: We propose to screen a library from previously FDA approved drugs with high chemical and pharmacological diversity and other with compounds marketed in Europe and/or Asia but not yet in the USA. A cut off of 50% inhibition in the HTS a-syn PMCA will be set up to prioritize the study of the drugs with higher potential. Other prioritization will be done based on the EC50, route of administration and side effects to reduce suffering in mice models. Second, study of the hits biological relevance in cell and mice models of Parkinson's disease. We plan to use PC12 cells overexpressing human alpha synuclein to study the presence or absence of insoluble alpha synuclein in the cells after transducing them with fibrils and in the presence of the hit drugs. We also want to use the A53T mice model that has widespread a-syn aggregation in the brain. The drug effect will be tested, before and simultaneously to the clinical symptoms appearance. With this time points we hope to stop the progression of the disease and reduce animal suffering.
Herva, ME et al. (2014) Anti-amyloid compounds inhibit alpha-synuclein aggregation induced by Protein Misfolding Cyclic Amplification (PMCA). J Biol Chem. doi:10.1074/jbc.M113.542340