Why don’t brain cells in Parkinson brains communicate better? A team of researchers in Aukland, New Zealand, have been working on that question for the last five years and have found some clues that may help both Parkinson’s and Alzheimer’s.
As new stem cells, immature cells, emerge in the brain, they need to grow into neurons and find their proper place in the brain and begin communicating with other neurons. In order to reach their destination, through a complex and tight inter cellular matrix, they become coated with a slippery substance, polysialic-acid-neutral cell adhesion molecule. This slippery substance reduces the friction so they can migrate and saves cell energy, but once the cell has found the right location, in order to be secured in position, the substance must be removed. Removal of the polysialic acid substance is also necessary for the dendrites (neural appendages) to connect with other neurons and begin to communicate. This process has been well known for many years, but what controls the process has been a mystery.
What happens to the slippery molecules when the cell no longer needs it? This team spent years trying many growth processes under various conditions before finding a clue. Actually, they found two clues. First, they learned that cells internalize the polysialic molecule dependent on cues received from collagen in the extra cellular matrix and gaseous molecules of nitrc oxide.
Then they found that if there is insulin in the matrix, the cell cannot absorb the slippery molecules. Parkinson’s and Alzheimer’s brains are less sensitive to insulin, so insulin is blocking the removal of the polysialic acid causing the cell to be unable to connect or communicate properly with other cells.
Dr. Maurice Curtis was the director of the study, and the experiments were done at the Centre for Brain Research laboratories in Aukland, New Zealand. Other researchers on the team were Dr. Hector Monzo, Distinqguished Professor Richard Fauli, Dr. Thomas Park, Dr. Birger Dieriks, Diedre Jansson and Professor Mike Dragunow. They have now begun testing new drug compounds to target the removal of polysialic acid from cells in hopes of improving the migration and connectivity of new stem cells in the brain.
Insulin and IGF1 modulate turnover of polysialylated neuronal cell adhesion molecule (PSA-NCAM) in a process involving specific extracellular matrix components
Hector J. Monzo1,2, Thomas I. H. Park1,3,Victor Birger Dieriks1,2, Deidre Jansson1,3,Richard L. M. Faull1,2, Mike Dragunow1,3,Maurice A. Curtis1,2,*
DOI: 10.1111/jnc.12363 Article Accepted for Publication