Dataset Information

Immunoprecipitation of Ribosome-Bound mRNAs from Astrocytic Perisynaptic Processes of the Mouse Hippocampus.

ABSTRACT: Translation of distally localized mRNAs is an evolutionary mechanism occurring in polarized cells. It has been observed in astrocytes, whose processes contact blood vessels and synapses. Here, we describe a protocol for the purification of the entire pool of ribosome-bound mRNAs in perisynaptic astrocytic processes (PAPs). Our procedure combines the preparation of synaptogliosomes with a refined translating ribosome affinity purification technique. This approach can be used in any brain region to probe the physiological relevance of local translation in PAPs. For complete details on the use and execution of this protocol, please refer to Mazaré et al. (2020).

SUBMITTER: Mazare N

PROVIDER: S-EPMC7757553 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Immunoprecipitation of Ribosome-Bound mRNAs from Astrocytic Perisynaptic Processes of the Mouse Hippocampus.

Mazaré Noémie N Oudart Marc M Cheung Giselle G Boulay Anne-Cécile AC Cohen-Salmon Martine M

STAR protocols 20201204 3

Translation of distally localized mRNAs is an evolutionary mechanism occurring in polarized cells. It has been observed in astrocytes, whose processes contact blood vessels and synapses. Here, we describe a protocol for the purification of the entire pool of ribosome-bound mRNAs in perisynaptic astrocytic processes (PAPs). Our procedure combines the preparation of synaptogliosomes with a refined translating ribosome affinity purification technique. This approach can be used in any brain region t ...[more]

PMID: 33377092

Similar Datasets

Project description:Local translation is a conserved molecular mechanism. It allows a cell with a complex shape to bypass somatic protein synthesis and transport, and thus to respond quickly to a local stimulus. Local translation also contributes to the establishment of molecular and functional polarity. In the brain, it has been extensively studied in neurons and has also been described more recently in astrocytes - a type of glial cell with specialized extensions that contact vessels and synapses. Here, we studied perisynaptic astrocytic processes (PAPs) in the dorsal hippocampus and showed that they contain RNAs, ribosomes, the endoplasmic reticulum-Golgi intermediate compartment, particles of the Golgi apparatus, and protein synthesis events. We used our recently refined polysome immunoprecipitation technique to characterize the pool of polysomal mRNAs in PAPs (which we refer to as the “PAPome”) from the dorsal hippocampus and compared it with the polysomal mRNAs found in the astrocyte as a whole. The polysomal transcripts that were enriched in the PAPome encoded mostly cytoplasmic proteins and defined an unexpected molecular repertoire with the most enriched transcripts coding for proteins involved in iron homeostasis, translation, cell cycle and cytoskeleton. Interestingly, among them Erz, Fth1, and Rplp1 were enriched in PAPs compared to perivascular astrocytic processes indicating that local translation differ at these two interfaces and may sustain distinct molecular properties. The PAP-enriched transcripts Flt1, Fth1, Ccnd2, Mdm2, Gnb2l1 and Eef1a1 code for proteins involved in memory and learning mechanisms. We therefore studied their local translation in the context of fear conditioning (i.e. behavior involving the dorsal hippocampus). We observed changes in the density and/or distribution of these mRNAs in astrocytes processes as well as a drop of their translation specifically in PAPs. Our results highlight unexpected molecular properties of hippocampal PAPs and suggest for the first time that local translation in this perisynaptic compartment is linked to fear-related memory.

Project description:The morphology of astrocytic processes determines their close structural association with synapses referred to as the 'tripartite synapse'. Concerted morphological plasticity processes at tripartite synapses are supposed to shape neuronal communication. Morphological changes in astrocytes as well as the motility of astrocytic processes require remodeling of the actin cytoskeleton. Among the regulators of fast timescale actin-based motility, the actin binding protein profilin 1 has recently been shown to control the activity-dependent outgrowth of astrocytic processes. Here, we demonstrate that cultured murine astrocytes in addition to the ubiquitous profilin 1 also express the neuronal isoform profilin 2a. To analyze the cellular function of both profilins in astrocytes, we took advantage of a shRNA mediated isoform-specific downregulation. Interestingly, consistent with earlier results in neurons, we found redundant as well as isoform-specific functions of both profilins in modulating cellular physiology. The knockdown of either profilin 1 or profilin 2a led to a significant decrease in cell spreading of astrocytes. In contrast, solely the knockdown of profilin 2a resulted in a significantly reduced morphological complexity of astrocytes in both dissociated and slice culture astrocytes. Moreover, both isoforms proved to be crucial for forskolin-induced astrocytic stellation. Furthermore, forskolin treatment resulted in isoform-specific changes in the phosphorylation level of profilin 1 and profilin 2a, leading to a PKA-dependent phosphorylation of profilin 2a. In addition, transwell assays revealed an involvement of both isoforms in the motility of astrocytic processes, while FRAP analysis displayed an isoform-specific role of profilin 1 in the regulation of actin dynamics in peripheral astrocytic processes. Taken together, we suggest profilin isoforms to be important modulators of astrocytic morphology and motility with overlapping as well as isoform-specific functions.

Dataset Information

Immunoprecipitation of Ribosome-Bound mRNAs from Astrocytic Perisynaptic Processes of the Mouse Hippocampus.

Publications

Immunoprecipitation of Ribosome-Bound mRNAs from Astrocytic Perisynaptic Processes of the Mouse Hippocampus.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets