Objective/Rationale:
A key event in the development of pathological changes in the nervous system of Parkinson’s disease patients is aggregation of a small synaptic protein: alpha-synuclein. Certain soluble products of alpha-synuclein aggregation can cause cell dysfunction and death. However, neurons are able to reduce the load of these toxic species by further aggregating them and dumping into less harmful inclusions. Unfortunately, in the adult brain this might lead to depletion of normal, functional alpha-synuclein; compromised synaptic transmission; and consequent health complications. Studies of this aspect of alpha-synuclein pathology were so far restrained by the absence of an adequate in vivo model. In this project we are going to fill this gap.
Project Description:
Recently we have engineered pre-clinical models with certain elements surrounding the gene encoding alpha-synuclein. In the presence of an active form of the enzyme ER-Cre, all genetic information between these elements gets eliminated. Thereby the cells are depleted of alpha-synuclein. In this project we will validate an experimental system for such inactivation of alpha-syniuclein in neurons at any desired time. For this we will breed pre-clinical models expressing ER-Cre only in neurons. We will then inject the models with tamoxifen, a drug that activates ER-Cre, and check the efficiency and specificity of alpha-synuclein depletion. Furthermore, we will gather preliminary data on the effect of adult onset alpha-synuclein dysfunction on physiology.
Relevance to Diagnosis/Treatment of Parkinson’s Disease:
As a major player in pathogenesis of Parkinson’s disease, alpha-synuclein is a promising therapeutic target. A commonly considered approach for developing new therapeutic interventions is to reduce alpha-synuclein production in the nervous system of patients. However, there is a serious concern that this might exuberate synaptic dysfunction along with the most devastating symptoms of the disease. Our experimental model will be invaluable for resolving this problem and choosing a safe way to combat pathology caused by alpha-synuclein dysfunction.
Anticipated Outcome:
Studies of the role of alpha-synuclein in the development of pathology in the brain of Parkinson’s disease patients would benefit from using a pre-clinical model in which the alpha-synuclein production gene can be inactivated at any time and in a specific group of neurons. We will produce this useful model and will use it in our studies but even more importantly, will make it available for other researchers.
This project was supported with a 2014 supplemental grant to characterize the pre-clinical model.
Final Outcome
The project’s goal was to create a new model of alpha-synuclein deficiency that could be further used for studying important aspects of Parkinson’s disease pathology. While generating this new model, we have encountered certain problems aroused from the side effect of our manipulations on the alpha-synuclein gene function. Despite these challenges the ultimate goal has been successfully achieved. Additional experiments were carried out to fully validate the model, i.e. to prove that in future experiments researchers will confidently attain alpha-synuclein depletion following induction of targeted rearrangement within the gene. In conclusion, a new model is now ready for further studies in our laboratory and for depositing to a biorepository, which shall assure unrestricted access for other researchers interested in using this model.