Damaged Neural Connections Repaired with Nanoparticles
A protein produced by specific cells in the brain has been shown to repair damaged brain networks. This discovery could allow a genetically engineered treatment for neurogenerative disorders such as Alzheimer’s.
A key hallmark of neurogenerative diseases is the decay of the connections between neurons in the brain. If these connections could be restored it is hoped that normal brain function can resume. Researchers have suspected that the specialised brain cells astrocytes may play a role in maintaining neural networks. Astrocytes direct new cells, regulate chemical signalling and process by-products of brain metabolism.
Astrocytes also produce a glutamate transporter protein, which is lost from the cells affected by a neurogenerative disease. Scientists genetically engineered mice to produce less neuron connections to stimulate the effects of a neurogenerative disease. They then identified the specific astrocyte cells that were still able to produce glutamate transporter proteins.
It was found that the astrocytes still able to produce glutamate transporter proteins also expressed much higher levels of a protein called norrin. When normal mouse brains were treated with norrin they grew new neural connections, whilst the mice with the gene coding for norrin silenced had much fewer neural connections.
The researchers then attached norrin proteins to nanoparticles and guide DNA for the astrocytes still able to produce glutamate transporter proteins. When the nanoparticles were injected into the brains that had their gene coding for norrin silenced new neural connections grew.
Further research is needed to identify the affect on norrin in animals with neurogenerative diseases. If successful, there could be an opportunity to cure these diseases by genetically engineering brain cells to produce norrin.