Protein clusters behind Parkinson’s finally seen

Researchers have directly seen and measured the protein clusters thought to spark Parkinson’s disease for the first time, marking a major milestone in understanding the condition.

These microscopic clusters, known as alpha-synuclein oligomers, have long been suspected as the starting point for Parkinson’s but had remained undetectable in human brain tissue until now.

A team from the University of Cambridge, UCL, the Francis Crick Institute and Polytechnique Montréal developed a powerful imaging approach that allows scientists to visualise, count and compare these protein clumps in human brain tissue.

One researcher described the breakthrough as “like being able to see stars in broad daylight”.

The findings could transform how scientists study Parkinson’s, offering insights into how it spreads through the brain and paving the way for earlier diagnosis and more targeted treatments.

Professor Sonia Gandhi from the Francis Crick Institute co-led the research.

Gandhi  said: “The only real way to understand what is happening in human disease is to study the human brain directly, but because of the brain’s sheer complexity, this is very challenging.

“We hope that breaking through this technological barrier will allow us to understand why, where and how protein clusters form and how this changes the brain environment and leads to disease.”

More than 166,000 people in the UK currently live with Parkinson’s disease, and the global total is expected to reach 25 million by 2050.

While existing drugs can ease symptoms such as tremors and stiffness, none can halt or slow the disease’s progression.

For over a century, doctors have identified Parkinson’s by the presence of large protein deposits known as Lewy bodies.

Yet researchers have long believed that smaller, early-stage oligomers – clusters of misfolded proteins just a few nanometres long – may actually cause the damage to brain cells.

Professor Steven Lee from Cambridge’s Yusuf Hamied Department of Chemistry, who co-led the research, said: “Lewy bodies are the hallmark of Parkinson’s, but they essentially tell you where the disease has been, not where it is right now.

“If we can observe Parkinson’s at its earliest stages, that would tell us a whole lot more about how the disease develops in the brain and how we might be able to treat it.”

To achieve this, the researchers created a method called ASA-PD (Advanced Sensing of Aggregates for Parkinson’s Disease).

This ultra-sensitive fluorescence microscopy technique can detect and analyse millions of oligomers in post-mortem brain samples.

Because the oligomers are so tiny, their signal is faint, but ASA-PD enhances that signal while reducing background noise, allowing scientists to clearly see individual alpha-synuclein clusters for the first time.

The researchers examined brain tissue from people with Parkinson’s and compared it to samples from healthy individuals of similar age.

They found that oligomers were present in both groups, but in those with Parkinson’s, the clusters were larger, brighter and far more numerous.

This difference suggests a strong connection between oligomer growth and disease progression.

The team also identified a unique subset of oligomers found only in Parkinson’s patients, which may represent the earliest detectable signs of the disease – possibly appearing years before symptoms emerge.

“This method doesn’t just give us a snapshot,” said professor Lucien Weiss from Polytechnique Montréal, who co-led the research.

“It offers a whole atlas of protein changes across the brain and similar technologies could be applied to other neurodegenerative diseases like Alzheimer’s and Huntington’s.

“Oligomers have been the needle in the haystack, but now that we know where those needles are, it could help us target specific cell types in certain regions of the brain.”