Scientists continue to make inroads into understanding the causes of neuro-developmental disorders like autism and schizophrenia. Researchers at the Salk Institute in California have discovered that cells in the brain called astrocytes initiate communication between two neurons and a disruption in this mechanism can lead to these disorders.
In a paper published in the journal Neuron, the research team details how astrocytes induce specific changes in between pairs of neurons across synapses– the small gap between neurons across which electrical signals flow – during brain formation.
Neurons make up about half the total number of cells in the bran. The other half includes various types of cells, the most abundant of which are astrocytes. It had previously been established that astrocytes secrete proteins that influence the development of neurons but they did not seem to have a role in communication between neurons.
Till a Salk scientist glypican 4 that somehow induced communication between nearby neurons. Astrocytes secrete glypican 4 and in the presence of this protein, neurons sending information partnered effectively with neurons receiving information via chemicals traveling across the synapse.
In the present study, the researchers conducted experiments by treating neuron cultures with two different types of astrocyte secreted proteins – glypican 4 and thrombospondin. They found that glypican 4 activated 49 genes while thrombospondin activated onlt three entirely different genes. This demonstrated that the two protins were involved in different different cellular pathways. It also indicated that glypican 4 is critical to making synapses active.
Further experiments showd that glypican 4 plays a role in increasing the numbers of chemical receptors on receiving neurons, making them more receptive to signals.
Here are the researchers talking about their findings.