In a paper published in Science, Glenn Dallérac’s team at the Institut des Neurosciences Paris-Saclay – NeuroPSI (CNRS/UPSaclay, Orsay), in collaboration with Nathalie Rouach’s team at the Centre Interdisciplinaire de Recherche en Biologie (Collège de France/CNRS/Inserm, Paris), shows a novel role for astrocytes in the brain plasticity that characterizes postnatal development.
Brain postnatal development is characterized by critical periods of experience-dependent remodeling. Termination of this period of intense plasticity is associated with settling of neuronal circuits, allowing for efficient information processing. Failure to end critical periods thus results in neurodevelopmental disorders. Yet, the cellular processes defining the timing of this developmental period remain unclear. The study of Glenn Dallérac and Nathalie Rouach shows that astrocytes control the closure of the critical period in the visual cortex. It uncovers a novel underlying pathway involving regulation of the extracellular matrix that allows interneurons maturation via an unconventional astroglial connexin signaling. Specifically, the timing of critical period closure is shown to be controlled by a marked developmental upregulation of the astroglial protein connexin 30 that inhibits expression of the matrix degrading enzyme MMP9 through the RhoA-GTPase signaling pathway. These results demonstrate that astrocytes not only influence activity and plasticity of single synapses, but are also key elements in the experience-dependent wiring of brain developing circuits.
Contact : Glenn Dallérac