A protein hiding inside brain cells once dismissed as mere "support staff" may hold a key to understanding why memories slip away in diseases like Alzheimer's — and how they might be restored.
Scientists at Baylor College of Medicine in Houston discovered that astrocytes, star-shaped cells that surround neurons like a protective cloud, directly control brain circuits that lock in memories during sleep. Their findings, published in the journal Neuron, suggest these overlooked cells do far more than just keep neurons running smoothly.
"Astrocytes have been implicated in learning and memory and in sleep regulation," said Dr. Benjamin Deneen, a professor at Baylor who led the research. "In the current study, we investigated how their roles in sleep facilitate the storage of memories."
The team zeroed in on a protein called NFIX, which is present in more than 80% of astrocytes across the adult mouse brain. When they disabled the gene that produces NFIX, something striking happened: astrocytes in one specific brain region called the thalamic reticular nucleus, or TRN, became smaller and less branched. These cells lost their complex, tree-like shapes and fewer connections to neighboring neurons.
The consequences went beyond cell shape. The mice with altered astrocytes still slept normally, but their brains produced unusual electrical patterns during sleep. More importantly, they struggled with memory tests — they performed poorly on tasks measuring working memory, object recognition and spatial navigation.
The researchers then traced exactly how this happened. They found that NFIX controls two molecular pathways involving GABA, a chemical astrocytes use to communicate with neurons. One pathway relies on a protein called MAOB to build GABA, while another uses P2RX7 to release it. Without NFIX, both proteins dropped in level, so astrocytes produced and released less GABA. This weakened a form of neuronal brake called tonic inhibition that keeps brain cells firing within a healthy range.
Here's the hopeful part: when the scientists restored either MAOB or P2RX7 in the modified astrocytes, both normal brain signaling and memory performance partially recovered. The mice got some of their memory function back.
"These findings provide evidence that astrocytes are much more than support cells for neurons — they also seem to directly regulate brain function," Dr. Deneen said.
The research may eventually help people with epilepsy, Alzheimer's disease and other conditions that involve memory problems. Because the study pinpointed specific proteins and pathways, scientists now have concrete targets to explore for new treatments.