Olfactory bulb astrocytes mediate sensory circuit processing through Sox9 in the mouse brain

Area of Science:

• Neuroscience
• Astrocyte Biology
• Sensory Processing

Background:

• While transcription factor roles in astrocyte development are known, their function in adult brain circuits and behavior is less understood.
• Astrocytes influence synaptic plasticity, but their role in maintaining sensory circuit architecture and function in adults requires further investigation.

Purpose of the Study:

• To investigate the role of the transcription factor Sox9 in adult olfactory bulb (OB) astrocytes.
• To determine how astrocyte-specific Sox9 deletion impacts sensory processing, neuronal function, and gene expression in the OB.

Main Methods:

• Astrocyte-specific deletion of Sox9 in adult mouse OB using genetic models.
• Assessment of olfactory behavior (odor detection and discrimination).
• Electrophysiological recordings of OB neurons and RNA-sequencing of OB astrocytes.

Main Results:

• Loss of astrocytic Sox9 led to anatomical and functional changes in OB astrocytes.
• Mice with astrocyte-specific Sox9 deletion exhibited decreased odor detection and discrimination abilities.
• Aberrant neuronal sensory response maps and impaired electrophysiological properties of mitral and tufted neurons were observed.
• RNA-sequencing revealed widespread gene expression changes, including reduced GLT-1 expression and altered glutamate transport.

Conclusions:

• Astrocytes are essential for physiological sensory processing in the adult brain.
• Astrocytic Sox9 is identified as a key transcriptional regulator of mature astrocyte function in the mouse OB.
• Sox9 regulates astrocyte-mediated glutamate transport, impacting neuronal function and sensory perception.