Lunatic Fringe-GFP Marks Lamina-Specific Astrocytes That Regulate Sensory Processing

Area of Science:

• Neuroscience
• Glial Cell Biology
• Spinal Cord Research

Background:

• Astrocytes, the most abundant glial cells in the central nervous system (CNS), are crucial for neuronal function.
• Astrocytes exhibit heterogeneity, but distinct subpopulations and their specific roles remain poorly understood.
• Identifying specific astrocyte markers and tools to access them is essential for understanding their functional diversity.

Purpose of the Study:

• To identify and characterize a specific astrocyte subpopulation in the dorsal spinal cord.
• To investigate the functional role of this identified astrocyte subpopulation in sensory processing.

Main Methods:

• Utilized the Lunatic Fringe-GFP (Lfng-GFP) reporter mouse line to specifically label astrocyte populations in laminae III and IV of the dorsal spinal cord.
• Performed transcriptional profiling of Lfng-GFP+ astrocytes to identify unique molecular signatures.
• Employed CRE-DOG viral tools to ablate Lfng-GFP+ astrocytes and assess the impact on neuronal activity and sensory function.

Main Results:

• The Lfng-GFP reporter specifically labeled astrocyte populations in laminae III and IV of the dorsal spinal cord.
• Transcriptional profiling revealed unique molecular profiles for Lfng-GFP+ astrocytes, enriched in Notch and Wnt pathway components.
• Ablation of Lfng-GFP+ astrocytes led to decreased neuronal activity in laminae III and IV and impaired light touch mechanosensation.
• Ablation also resulted in reduced glutamatergic synapses in the affected spinal cord regions.

Conclusions:

• Lfng-GFP+ astrocytes represent a distinct, anatomically localized subpopulation in the dorsal spinal cord.
• These astrocytes play a direct role in supporting neuronal function and sensory responses, particularly light touch.
• The findings highlight the importance of astrocyte heterogeneity in CNS function and provide a tool for further investigation.