Parkinson’s disease (PD) researchers have done much to characterize the malfunctioning form of the protein alpha-synuclein in its disease progression. However, less is known about the normal function of this protein in a healthy context. Research from the University of Cambridge now offers clues as to how it might behave in a healthy brain, hinting at new avenues for treatment.
Alfonso De Simone and Christopher Dobson published the results in the journal Nature.
Biologists refer to PD as a “protein misfolding disease" because the protein structures required for normal function are altered, triggering disease. Much work has been done on the protein alpha-synuclein, a hallmark protein to go awry in PD, yet its mechanism isn’t known.
“We needed to know what alpha-synuclein actually does in order to identify the right strategies to target it as a therapeutic approach to Parkinson's,” said De Simone in a statement.
The researchers relied on a lab-based approach to characterize the same synaptic vesicles as those found in the human brain. They exposed these to different mutated (and healthy) versions of alpha-synuclein and using nuclear magnetic resonance spectroscopy watched where the protein localized to in this process.
Vesicles are tiny carriers of neurotransmitters essential for the relaying of information across the synapse in the brain. They found that alpha-synuclein regulated the release of vesicles across the synapse, and by holding vesicles back they can control whether signals are carried to the recipient neuron.
"It is a sort of shepherding effect by alpha-synuclein that occurs away from the synapse itself, and controls the number of synaptic vesicles used in each transmission," said Giuliana Fusco, a graduate student who performed these sets of experiments.
In patients with early onset PD arising from a genetic mutation, alpha-synuclein malfunctions and the normal synaptic release of vesicles is altered. The hallmark of an alpha-synuclein excess in these patients could be reflected in their symptoms due to this mechanism.
"At this stage we can only really speculate about the wider implications of these findings and more research is needed to test some of those ideas," De Simone concluded in the release. "Nevertheless, this does seem to explain a large body of biochemical data in Parkinson's research."