The Effect of 4-hydroxy-2-nonenal Modification on Alpha-synuclein Toxicity

Objective/Rationale:
Alpha-synuclein is a protein that is normally produced in the human brain. Compelling evidence suggests that alpha-synuclein can acquire a toxic feature that kills dopamine secreting nerve cells in perhaps most people with Parkinson’s disease. Using fruit flies as
an animal model, we have identified a chemical modification of alpha-synuclein that we hypothesize is responsible for converting it to a toxic form. To explore this hypothesis we will test whether preventing this modification influences alpha-synuclein toxicity.

Project Description:
In previous work, we have found that producing alpha-synuclein protein in the fruit fly brain kills some of the dopamine-secreting nerve cells-the very same type that die in people with Parkinson’s disease. More recently, we have found that the chemical, 4- hydroxy-2-nonenal (HNE), can form stable bonds with alpha-synuclein and that this modification occurs shortly before nerve cells begin to die in our fly model, suggesting that HNE converts alpha-synuclein to a toxic entity. To test this hypothesis, we must first identify where HNE binds to alpha-synuclein. We will do this by breaking HNE-modified alpha-synuclein into small fragments and looking at which of the fragments contain the HNE-modification using a technique called mass spectrometry. We will then create altered versions of alpha-synuclein that cannot be modified by HNE, introduce them into flies and test whether they are no longer toxic.

Relevance to Diagnosis/Treatment of Parkinson’s Disease:
While alpha-synuclein is thought to play a pathogenic role in perhaps most people with Parkinson’s disease, it is unclear how alpha-synuclein becomes toxic. We hypothesize that HNE binds to alpha-synuclein and converts it to a toxic entity. If our hypothesis is correct, our work could lead to the development of pharmacological agents that prevent HNE formation (several of which already exist), and thus prevent or delay the onset of Parkinson’s disease.

Anticipated Outcome:
We expect to learn whether the modification of alpha-synuclein by HNE converts alpha-synuclein into a toxic entity that causes Parkinson’s disease. If this model is correct, our findings would further suggest that differences in HNE metabolism may distinguish people that develop Parkinson’s disease from those that do.