Investigation of alpha-synuclein pathogenic mechanisms with human stem cells and neurons

Parkinson's disease (PD) is a progressive degenerative disorder of the brain. A mixture of environmental and genetic triggers are thought to cause the sporadic forms of this condition. A common link between all cases of PD is the unusual and damaging behaviour of a protein known as alpha-synuclein. This protein is present in neurons of all people, and is usually benign. However, in people with Parkinson's and some forms of dementia, alpha-synuclein takes on unusual shapes and becomes toxic to neurons, eventually killing them. A second unpleasant property of this protein is that it is thought to travel through the brain spreading disease. This behaviour may be similar to how prion protein from infected beef can spread from gut neurons into the spinal cord, and eventually into the brain causing severe neurological problems. We propose to use live human neurons to model the disease-causing behaviour of alpha-synuclein in the laboratory. We have recently published induced pluripotent stem cells (iPSCs) from a patient with 4 copies of the gene encoding alpha-synuclein, instead of the normal two copies. This patient and about half the members of her family get a severe, early-onset form of PD with dementia. The neurons made from PD iPSCs produce twice as much alpha-synuclein protein as control neurons from an unaffected 1st-degree relative of this patient. The PD and healthy neurons will be used in comparative studies to investigate any problems caused by over-production of alpha-synuclein. In parallel work, human embryonic stem cells (hESCs) were genetically modified to over-produce alpha-synuclein at a wide range from 2-fold to 6-fold above normal levels. Both iPSCs and hESCs will be used to investigate the unusual behaviour of alpha-synuclein including its neurotoxic properties. If reproducible, disease-causing behaviour is observed, these cells will be ideal for modeling PD and understanding how alpha-synuclein kills neurons. This system will be used for screening drugs that could stop the harmful behaviour of alpha-synuclein. Several pilot screens of a select number of compounds will be performed to determine the feasibility of this approach. Potent drugs that prevent the misfolding and pathological behaviour of alpha-synuclein will change the face of PD and dementia treatment by stopping or severely retarding the progression of the disease.

Parkinson's disease (PD) is a progressive neurodegenerative disorder with no known cure. A prevailing model of PD progression suggests that the small pre-synaptic protein alpha-Synuclein (aSyn) misfolds and forms aggregates the cause neuronal dysfunction and death. Futhermore, these misfolded aggregates are proposed to travel through the brain in a prion-like manner. The exact mechanism of how aSyn causes neuronal death is not known, but significant evidence suggests it directly compromises mitochondrial function. Neuroprotective compounds that prevent or reduce aSyn toxicity halt or slow the progression of PD. Using iPSC lines from a patient with alpha-synuclein triplication, and hESCs engineered to overexpress aSyn, I propose to establish a robust, semi-automated fluorescence-based system to read-out alpha-synuclein phenotypes.

Neuroscience and stem cell researchers: The work proposed in this project will investigate the pathogenic behaviour of a central protein at the root of Parkinson's. This will be looked at for the first time in authentic human Parkinson's neurons. The cell lines (iPSC and hESC) generated as part of this study will be of extreme interest to other academics wishing to studying this condition in the lab. All cell lines will be shared post-publication, and some cell lines will be shared pre-publication.

Local research community: There are several labs in the MRC CRM and the Centre for Neuroregeneration interested in using human pluripotent stem cells to model diseases. I have shared by iPSC and neural induction protocols with Prof Ian Wilmut and Prof Siddharthan Chandran, and will continue to share expertise with labs doing similar work.

Wider academic community: I will publish all findings in peer-reviewed journals in an open-access format, and make all protocols available through my website. I will also present my work an scientific conferences with a diverse audience, including the 3rd World Parkinson Congress. My work may influence the way scientists in other neurodegenerative fields, such as Alzheimer's, approach disease modelling and drug screening.

Junior Researchers: Over the course of the proposed grant, several undergraduate honours students and PhD students will be involved with several aspects. Most of the preliminary data in this proposal has been generated by PhD students.

Biotech/pharma industry: My major goal it to established a high-content screening platform to identify novel drugs or novel activities of known drugs. If the platform proves robust I would anticipate considerable interest from companies endeavouring to discover new treatments for intractable conditions, such as Parkinson's. Furthermore, companies such as Antoxis, that design drugs, but do not have the capability to screen them will also be keenly interested in collaborating.

General Public: My recent published work on Parkinson's iPSCs was covered by BBC news (on-line), The Scotsman, The Times, The Daily Telegraph, and most importantly, The Metro. I also participated in a 40-min discussion on the BBC World Service (www.bbc.co.uk/programmes/p00jnf02). I have also accepted an invitation to The Vatican to present my work at a "Responsible Stem Cell Research" conference in April 2012. They are very keen that am doing stem cell research without destroying embryos. There is a strong personal interest in my research by people with Parkinson's and their family and carers. I present my research to people with Parkinson's on a regular basis (~9 times in 2011 so far). I also host a special interest group of people with Parkinson's that are keenly interested in basic research. We have meet twice at the MRC CRM this year, with a third meeting scheduled in December, 2011. The main purpose of the group is to raise awareness of Parkinson's research and increase participation of patients in research studies and clinical trials.

Medicine: In the long-term my work may directly or indirectly lead to disease-modifying drugs for Parkinson's. This would have a very large impact on the way this condition is treated, and on the quality of life of people living with Parkinson's. The methodology used in this proposal may also be applicable to other neurodegenerative diseases that have misfolded proteins driving it. For example, Tau for Alzheimer's and TDP-43 for motor neurone disease