Activity-Dependent PSD Formation and Stabilization of Newly Formed Spines in Hippocampal Slice Cultures

Roo, Mathias De; Klauser, Paul; Méndez, Pablo; Poglia, Lorenzo; Michelet, Dominique

doi:10.1093/cercor/bhm041

Cited by 128 publications

(146 citation statements)

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“…Hippocampal organotypic slice cultures (400-μm thick) were prepared from postnatal 5-to 6-d-old C57BL/6 Fmr1 +/y or its Fmr1 −/y littermate mice by using a protocol approved by the Geneva veterinary office and maintained under culture conditions as described (52). Transfection was carried out at 7 DIV with a biolistic method (Helios Gene Gun; Bio-Rad) using gold beads coated with mRFP and either pAAV-EGFP-shRNA-Dgkκ, pAAV-EGFP-shRNA-scramble, pAAV-hSynapsin-EGFP, or pAAV-hSynapsin-Dgkκ.…”

Section: Aav Vector Constructionmentioning

confidence: 99%

“…Transfection was carried out at 7 DIV with a biolistic method (Helios Gene Gun; Bio-Rad) using gold beads coated with mRFP and either pAAV-EGFP-shRNA-Dgkκ, pAAV-EGFP-shRNA-scramble, pAAV-hSynapsin-EGFP, or pAAV-hSynapsin-Dgkκ. Repetitive confocal imaging was performed as described (52). Briefly, dendritic segments of CA1 transfected neurons (30-40 μm in length) were imaged from 12 to 15 DIV (at 0, 5, 24, 48, and 72 h) by using an Olympus Fluoview 300 system, and analysis of the Z-stacked images obtained was performed by using Osirix software.…”

Section: Aav Vector Constructionmentioning

confidence: 99%

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Fragile X Mental Retardation Protein (FMRP) controls diacylglycerol kinase activity in neurons

Tabet

Moutin

Becker

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

102

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Fragile X syndrome (FXS) is caused by the absence of the Fragile X Mental Retardation Protein (FMRP) in neurons. In the mouse, the lack of FMRP is associated with an excessive translation of hundreds of neuronal proteins, notably including postsynaptic proteins. This local protein synthesis deregulation is proposed to underlie the observed defects of glutamatergic synapse maturation and function and to affect preferentially the hundreds of mRNA species that were reported to bind to FMRP. How FMRP impacts synaptic protein translation and which mRNAs are most important for the pathology remain unclear. Here we show by cross-linking immunoprecipitation in cortical neurons that FMRP is mostly associated with one unique mRNA: diacylglycerol kinase kappa (Dgkκ), a master regulator that controls the switch between diacylglycerol and phosphatidic acid signaling pathways. The absence of FMRP in neurons abolishes group 1 metabotropic glutamate receptor-dependent DGK activity combined with a loss of Dgkκ expression. The reduction of Dgkκ in neurons is sufficient to cause dendritic spine abnormalities, synaptic plasticity alterations, and behavior disorders similar to those observed in the FXS mouse model. Overexpression of Dgkκ in neurons is able to rescue the dendritic spine defects of the Fragile X Mental Retardation 1 gene KO neurons. Together, these data suggest that Dgkκ deregulation contributes to FXS pathology and support a model where FMRP, by controlling the translation of Dgkκ, indirectly controls synaptic proteins translation and membrane properties by impacting lipid signaling in dendritic spine.F ragile X syndrome (FXS), the most common cause of inherited intellectual disability and autism, is due to the transcriptional inactivation of the Fragile X Mental Retardation 1 gene (FMR1) (1, 2). The FMR1 knockout (KO) mouse (Fmr1 −/y ) replicates phenotypes similar to human symptoms-including autistic-like behaviors, cognitive deficits, and hyperactivity-as well as abnormal dendritic spine morphology (3). FMR1 encodes Fragile X Mental Retardation Protein (FMRP), an RNA-binding protein associated to polyribosomes and involved in the translational control of mRNAs important for synaptic plasticity (4). Consistent with a posttranscriptional function, the absence of FMRP in Fmr1 −/y mouse causes abnormal signaling of group 1 metabotropic glutamate receptors (mGluRI), leading to several forms of abnormal synaptic plasticity that rely on protein translation (5, 6). Protein expression analyses confirmed a role of FMRP in neuronal translational control (7), but the extent of this control remains unclear. Although several studies focusing on individual mRNA targets (e.g., Fmr1, Map1b, Psd95, App, etc.) suggest specific control by FMRP (2), studies of global translation, including in vivo labeling in the Fmr1 −/y mouse (8), showed thousands of neuronal proteins deregulated in the absence of FMRP, pointing toward a general translational derepression. Studies seeking to identify the transcripts controlled by FMRP identified can...

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Section: Aav Vector Constructionmentioning

confidence: 99%

Section: Aav Vector Constructionmentioning

confidence: 99%

Fragile X Mental Retardation Protein (FMRP) controls diacylglycerol kinase activity in neurons

Tabet

Moutin

Becker

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

102

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“…In vivo imaging of individual spines for days to months has shown that adult spines are largely stable but a small subpopulation remains plastic (3, 7) and spine turnover is increased by novel experience (5,(8)(9)(10). Whereas most new spines are thin and withdraw rapidly, some enlarge and form stable synaptic contacts (2,3,7,(11)(12)(13)(14). In fact, the stabilization of a subset of new spines correlates with behavioral performance in several different tasks in multiple animal species (13,(15)(16)(17).…”

mentioning

confidence: 99%

“…Spines have been reported to incorporate AMPA receptors early in their development (13,27,28). Apart from additional roles in long-lasting synapses, AMPA receptor activity has been associated with the stabilization of immature spines, possibly, at least in part, via actin-dependent pathways (4,14,(29)(30)(31)(32)(33)(34)(35).In neurons, the O-GlcNAc pathway has emerged recently as critical for coupling cellular function to energy availability through nutrient-dependent flux via the hexosamine biosynthesis pathway (HBP), of which the OGT donor substrate uridine diphosphate (UDP)-GlcNAc is the end product (36-40). Unlike complex glycans present on the outside of cells and in the secretory pathway, O-GlcNAc is a highly dynamic sugar that is added and removed repeatedly over the lifespan of a single peptide chain.…”

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confidence: 99%

O-GlcNAc transferase regulates excitatory synapse maturity

Lagerlöf

Hart

Huganir

2017

Proc. Natl. Acad. Sci. U.S.A.

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Experience-driven synaptic plasticity is believed to underlie adaptive behavior by rearranging the way neuronal circuits process information. We have previously discovered that O-GlcNAc transferase (OGT), an enzyme that modifies protein function by attaching β-N-acetylglucosamine (GlcNAc) to serine and threonine residues of intracellular proteins (O-GlcNAc), regulates food intake by modulating excitatory synaptic function in neurons in the hypothalamus. However, how OGT regulates excitatory synapse function is largely unknown. Here we demonstrate that OGT is enriched in the postsynaptic density of excitatory synapses. In the postsynaptic density, O-GlcNAcylation on multiple proteins increased upon neuronal stimulation. Knockout of the OGT gene decreased the synaptic expression of the AMPA receptor GluA2 and GluA3 subunits, but not the GluA1 subunit. The number of opposed excitatory presynaptic terminals was sharply reduced upon postsynaptic knockout of OGT. There were also fewer and less mature dendritic spines on OGT knockout neurons. These data identify OGT as a molecular mechanism that regulates synapse maturity.O-GlcNAc | OGT | excitatory synapses | AMPA receptors N euronal synapses, the cell-cell junctions over which neurons communicate, are formed and eliminated throughout life, and their turnover has for decades been associated with the way neuronal circuits adapt to environmental challenges to optimize behavior (1, 2). In both humans and animals, early development is characterized by massive generation of new synapses. About half of all synapses are then lost during adolescence (2, 3). Most mature excitatory synapses occur on dendritic protrusions called spines and essentially all spines contain an excitatory synapse (4-6). In vivo imaging of individual spines for days to months has shown that adult spines are largely stable but a small subpopulation remains plastic (3, 7) and spine turnover is increased by novel experience (5,(8)(9)(10). Whereas most new spines are thin and withdraw rapidly, some enlarge and form stable synaptic contacts (2,3,7,(11)(12)(13)(14). In fact, the stabilization of a subset of new spines correlates with behavioral performance in several different tasks in multiple animal species (13,(15)(16)(17). Rather than synapse formation or density, the selection of which spines are retained once formed has been suggested to match circuit architecture with behavior (18). Without affecting spine formation, deleting β-adducin, which regulates actin, perturbed the process by which nascent spines establish functional synapses and impaired long-term memory (19). Fragile X syndrome, a common form of mental retardation, exhibits a higher than normal density of spines but more of them exhibit an immature morphology and their turnover is not affected by sensory experience (9,20). Conversely, the protein Telencephalin arrests the maturation of spines and its removal enhances several forms of learning (13,21,22).Although many molecules have been identified that affect synapse number, it is unclear h...

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“…The scaffold protein PSD-95 is highly abundant at [15], and clusters very early at [16][17][18] excitatory synapses. Further, PSD-95 is more strongly associated with stable than transient spines [19], and is thought to accelerate synaptic maturation [3,[20][21][22] through coordinated regulation of postsynaptic AMPA-type glutamate receptors (GluARs) [23][24][25] and neuroligins [26,27]. Synaptic PSD-95 levels increase during development and with time in vitro [28,29], over a similar developmental window there is a reduction in synapse turnover [30], and knockdown of PSD-95 increases spine turnover [31].…”

Section: Introductionmentioning

confidence: 99%

PSD-95 promotes the stabilization of young synaptic contacts

Taft

Turrigiano

2014

Phil. Trans. R. Soc. B

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Maintaining a population of stable synaptic connections is probably of critical importance for the preservation of memories and functional circuitry, but the molecular dynamics that underlie synapse stabilization is poorly understood. Here, we use simultaneous time-lapse imaging of post synaptic density-95 (PSD-95) and Ca 2+ /calmodulin-dependent protein kinase II (CaMKII) to investigate the dynamics of protein composition at axodendritic (AD) contacts. Our data reveal that this composition is highly dynamic, with both proteins moving into and out of the same synapse independently, so that synapses cycle rapidly between states in which they are enriched for none, one or both proteins. We assessed how PSD-95 and CaMKII interact at stable and transient AD sites and found that both phospho-CaMKII and PSD-95 are present more often at stable than labile contacts. Finally, we found that synaptic contacts are more stable in older neurons, and this process can be mimicked in younger neurons by overexpression of PSD-95. Taken together, these data show that synaptic protein composition is highly variable over a time-scale of hours, and that PSD-95 is probably a key synaptic protein that promotes synapse stability.

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Activity-Dependent PSD Formation and Stabilization of Newly Formed Spines in Hippocampal Slice Cultures

Cited by 128 publications

References 47 publications

Fragile X Mental Retardation Protein (FMRP) controls diacylglycerol kinase activity in neurons

Fragile X Mental Retardation Protein (FMRP) controls diacylglycerol kinase activity in neurons

O-GlcNAc transferase regulates excitatory synapse maturity

PSD-95 promotes the stabilization of young synaptic contacts

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