How does Parkinson's spread in the brain?

A new study led by researchers at Will Cornell School of Medicine shows that protein α-synuclein aggregates spread
through the brains of Parkinson's disease patients through a process of cellular waste ejection.

In this process, known as lysosomal exocytosis, neurons expel protein waste that
cannot be broken down and recycled.

"Our findings also suggest that lysosomal exocytosis may be a general mechanism for processing neuronal aggregation and anti-degrading proteins in normal, healthy environments and neurodegenerative diseases," said the study's senior author, Dr.

Parkinson's is a disease characterized by neurons dying in the brain in a typical way, often lasting for decades
.

An important finding in Parkinson's research over the past few decades is that the death of neurons in the disease occurs
with the spread of abnormal aggregation in the brain of a neuronal protein, α-synuclein, α-synuclein.

In the study, Dr.

Lysosomes contain enzymes that can break down proteins and other molecular wastes into building blocks, essentially digesting and recycling them
.

The researchers also showed in further experiments that by reducing lysosomal exocytosis, they could reduce the apparent concentration
of diffusible aggregates.

"We don't know yet, but if neurons keep these aggregates in the lysosome, even in the long run, they might be in a better
situation," he said.

Dr.

The team is currently continuing to study the role of lysosomes in Alzheimer's
disease.

Ying Xue Xie, Nima N.