Scientists Find that Lewy Bodies Spread from Cell to Cell

The main component of Lewy bodies is a protein called alpha-synuclein. An accumulation of alpha-synuclein is toxic to cells. Alpha-synuclein and Lewy bodies appear to spread through the brain as Lewy body disease and Parkinson's disease progress. Also, Lewy bodies seem to spread into healthy cells placed into the brains of people with Parkinson's disease. Scientists have now made some key findings about how alpha-synuclein spreads.

Researchers at the University of California, San Diego and Konkuk University in Seoul, South Korea, discovered that alpha-synuclein is transmitted from cell to cell. They first cultured neural precursor cells with neuronal cells expressing alpha-synuclein. After 24 to 48 hours, alpha-synuclein was found in the precursor cells, which suggested cell-to-cell transmission. They then discovered that alpha-synuclein is transmitted via endocytosis, the normal process by which cells absorb proteins. Blocking endocytosis resulted in less accumulation of alpha-synuclein. The researchers also found that a factor was the failure of the quality-control systems of cells, which would usually degrade and remove protein aggregates.

The researchers went on to study mice with Parkinson-like brains. They grafted healthy stem cells to the brain tissue. After four weeks, Lewy bodies were common in the grafted cells. Again, this supported the view that alpha-synuclein and Lewy bodies spread from cell to cell.

Hopefully, findings like these will help scientists discover ways to prevent cells from accumulating alpha-synuclein or to help the cells clear the alpha-synuclein out.

For more information, see the press release about this research. The research was published in the Proceedings of the National Academy of Sciences on August 4, 2009; see the abstract online.