(CTN News) – It has been discovered that the mutated proteins that are a hallmark of Parkinson’s disease spread and aggregate in the brain as a result of the disease.
As a result of the discovery, there may be a way of halting the progression of the disease, and it may also prove useful in tackling other neurodegenerative diseases caused by protein aggregation in the future.
The protein alpha-synuclein was discovered more than 20 years ago to play a critical role in the development of Parkinson’s disease (PD). In the presence of toxic, mutated alpha-synuclein, Lewy bodies are thought to form, resulting in progressive neuronal death.
In addition to Alzheimer’s disease, alpha-synuclein is also associated with Lewy body dementia, the second most common form of dementia following Alzheimer’s disease.
Research has established an association between neurodegenerative disorders and the aggregation and spread of proteins such as alpha-synuclein.
What remains unclear, however, is what occurs first: aggregation or spread. Researchers at the Toyko Medical and Dental University have provided answers to these questions in a new study.
Kyota Fujita, the study’s lead author, explained that most experiments have so far used fibrils, which are the clumps formed when monomeric alpha-synuclein aggregates.
Fibrils are transmitted from neurons to neurons, but it remains unclear whether monomers behave similarly.
The researchers injected mutated alpha-synuclein with green fluorescent protein into mice’s brains in order to determine how monomers and fibrils of alpha-synuclein move around the brain. Because any cell can contribute to the spread of alpha-synuclein, viral particles were used to enable its synthesis in the cells surrounding the injection site.
The researchers noticed fluorescence in remote brain regions two weeks after injection, indicating the monomeric mutated alpha-synuclein was spreading.
Fluorescent proteins were found in the glymphatic system, a unique arrangement of channels that eliminate proteins and metabolites from the central nervous system, and were taken up by neurons. A year later, they found that the monomers had clumped together into fibrils.
Hitoshi Okazawa, the study’s corresponding author, said alpha-synuclein fibrils formed after monomers propagated. “Specifically, we found alpha-synuclein monomer in the glymphatic system and remote regions as early as two weeks after injection, while alpha-synuclein fibrils were observed 12 months after injection! ”
The researchers noted that the amount of alpha-synuclein aggregation and the time it took to form varied andnot proportional to the distance from the injection site.
They say the study provides an improved understanding oftravels through the brain and may be used to target its spread early in PD development,
And, they say, the findings could be generalized to other proteins that cause neurodegenerative diseases.