Astroglial ER-mitochondria calcium transfer mediates endocannabinoid-dependent synaptic integration

Area of Science:

• Neuroscience
• Cell Biology
• Astrocyte Biology

Background:

• Astroglial calcium signaling is crucial for synaptic transmission and plasticity.
• Mitochondria-endoplasmic reticulum contacts (MERCs) influence calcium dynamics but their role in astrocytes is unknown.

Purpose of the Study:

• To investigate the role of astrocyte mitochondrial-associated type-1 cannabinoid (mtCB1) receptors in MERCs and brain function.
• To explore the impact of mtCB1 receptor activation on astroglial calcium signaling and synaptic integration.

Main Methods:

• Activation of mtCB1 receptors in astrocytes.
• Studying calcium transfer from endoplasmic reticulum to mitochondria via the mitochondrial calcium uniporter (MCU).
• Electrophysiological recordings in hippocampal slices.

Main Results:

• mtCB1 receptor activation promotes calcium transfer to mitochondria through MCU.
• mtCB1-dependent mitochondrial calcium uptake regulates astrocyte cytosolic calcium dynamics.
• Blocking mtCB1 receptors or MCU in astrocytes impairs lateral synaptic potentiation.

Conclusions:

• Astrocyte mtCB1 receptors at MERCs regulate intracellular calcium signaling.
• Endocannabinoid signaling via mtCB1 receptors modulates astroglial control of synaptic integration and brain network function.