Local Translation in Perisynaptic Astrocytic Processes Is Specific and Changes after Fear Conditioning
Noémie Mazaré1, Marc Oudart1, Julien Moulard2
1Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France; Doctoral School No. 158, Pierre and Marie Curie University, 75005 Paris, France.
Cell Reports
|August 27, 2020
Summary
Astrocytes in the brain perform local translation, a process vital for rapid cellular responses. This study reveals specific RNA molecules in astrocyte processes at synapses, crucial for memory and learning.
Area of Science:
- Neuroscience
- Molecular Biology
- Cell Biology
Background:
- Local translation allows cells to rapidly respond to stimuli.
- Astrocyte processes, particularly perisynaptic astrocytic processes (PAPs), are known to contact synapses and blood vessels.
- The specific mRNA content and regulatory mechanisms of local translation in astrocytes remain largely unexplored.
Purpose of the Study:
- To investigate the presence and characteristics of local translation machinery in hippocampal PAPs.
- To identify the specific pool of ribosome-bound mRNAs localized in PAPs and compare it to whole astrocytes.
- To explore the role of astrocyte local translation in neuronal plasticity, such as memory and learning.
Main Methods:
- Utilized a refined immunoprecipitation technique to isolate and identify ribosome-bound mRNAs in PAPs.
- Compared the transcriptome of PAPs with that of the whole astrocyte.
- Analyzed changes in RNA distribution and ribosome-bound status following fear conditioning.
Main Results:
- Confirmed the presence of translation machinery within PAPs.
- Identified a distinct subset of mRNAs specifically enriched in PAPs at the synaptic interface.
- Discovered that these PAP-enriched transcripts encode proteins involved in iron homeostasis, translation, cell cycle, and cytoskeleton regulation.
- Observed significant alterations in RNA distribution and ribosome binding in PAPs after fear conditioning.
Conclusions:
- Astrocyte perisynaptic processes contain a specific and polarized pool of translation machinery.
- This localized translation machinery is dynamically regulated and plays a role in adaptive cellular responses, including those related to memory and learning.
- These findings highlight astrocytes as key players in synaptic function and plasticity through local translational control.
