Study Rationale:
Filamentous aggregates of the protein alpha-synuclein underlie several neurodegenerative diseases, called synucleinopathies. Parkinson’s disease (PD) is the most common synucleinopathy. Over the past five years, we have solved cryo-EM structures of alpha-synuclein filaments from the brains of individuals with various synucleinopathies. We now propose to solve the structures of alpha-synuclein filaments from the brains of individuals with additional synucleinopathies, to determine the molecular identities of the non-proteinaceous densities that are associated with filaments and to develop methods to make filaments with these structures from recombinants protein. Neither the reported structures of pre-formed fibrils, nor those of filaments amplified from brain, are the same as those of alpha-synuclein filaments from the human brain.
Hypothesis:
What are the structures of alpha-synuclein filaments from human brains and how can one reproduce them in experimental systems?
Study Design:
This project is centered around structure determination of alpha-synuclein filaments from the human brain using cryo-EM. We will determine the structures of alpha-synuclein filaments from the brains of individuals with several synucleinopathies, similar to what we have done over the past five years. We will use immunoprecipitation, mass spectrometry and cryo-EM to identify the molecular nature of the non-proteinaceous densities present in the filament structures from the human brain. Finally, we propose to develop methods to make filaments with some of the human brain structures from recombinant protein.
Impact on Diagnosis/Treatment of Parkinson’s disease:
The assembly of alpha-synuclein into filaments is central to PD. To understand the mechanisms of filament formation, it is essential to develop methods to make filaments with the same structures as those from the human brain using recombinant protein. This is necessary for the development of mechanism-based therapeutics and better diagnostics.
Next Steps for Development:
To use recombinant alpha-synuclein filaments of known structure for the screening of compounds that prevent filament formation and/or block filament growth. To use these filaments for the docking of compounds in order to develop new PET ligands.