By James Deng

Astrocytes are star-shaped cells that constitute around one fifth of all cells in the human brain. Each astrocyte ensheaths thousands of neuron-to-neuron contacts (synapses), and this proximity enables astrocytes to closely tailor the synaptic environment both in health and disease. Emerging work has shown astrocytes not only to promote brain homeostasis, but also to release specific factors at distinct timepoints to guide development, maturation, and breakdown of synapses.

Most research in Fragile X syndrome has focused on changes in neurons, but astrocytes have increasingly been shown to play a role. Growing typically developing neurons with the factors released from Fragile X astrocytes leads the neurons to display alterations similar to findings in Fragile X patients. Recently, we found a pathway — the bone morphogenetic protein (BMP) signaling pathway — that is activated in Fragile X astrocytes and is responsible for many of the changes in astrocyte-released factors specific to Fragile X.

This project aims to target the BMP pathway in astrocytes: We will ask whether deactivating this pathway can improve multiple characteristics of Fragile X mice. Using methods including genetics, viruses, and drugs, we will dissect this pathway and characterize its significance to Fragile X. We will also determine which specific astrocyte released factors are changed in Fragile X, so as to generate leads for potential therapeutic targets.