VAP spatially stabilizes dendritic mitochondria to locally support synaptic plasticity
Ontology highlight
ABSTRACT:
INSTRUMENT(S): maXis, LTQ Orbitrap Elite, Q Exactive
ORGANISM(S): Rattus Norvegicus (rat)
TISSUE(S): Brain
SUBMITTER: 
Julian Langer
LAB HEAD: Julian Langer
PROVIDER: PXD047226 | Pride | 2023-11-27
REPOSITORIES: Pride
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Project description:Excitatory synapses occur mainly on dendritic spines, and spine density is usually correlated with the strength of excitatory synaptic transmission. We report that Nr4a1, an activity-inducible gene encoding a nuclear receptor, regulates the density and distribution of dendritic spines in CA1 pyramidal neurons. Nr4a1 overexpression resulted in elimination of the majority of spines; however, postsynaptic densities were preserved on dendritic shafts, and the strength of excitatory synaptic transmission was unaffected, showing that excitatory synapses can be dissociated from spines. mRNA expression profiling studies suggest that Nr4a1-mediated transcriptional regulation of the actin cytoskeleton contributes to this effect. Under conditions of chronically elevated activity, when Nr4a1 was induced, Nr4a1 knockdown increased the density of spines and PSDs specifically at the distal ends of dendrites. Thus, Nr4a1 is a key component of an activity-induced transcriptional program that regulates the density and distribution of spines and synapses. After 10 days in culture, dissociated mouse hippocampal neurons in 6-well plates were infected with lentivirus expressing either Flag-Nr4a1 or GFP and incubated for 6 days to allow for transgene expression. Total RNA was then isolated using RNeasy Plus kit (QIAGEN). Samples passing an mRNA quality check proceeded to quantitative analysis on Agilent-026655 4x44 Mouse Microarrays.
2016-01-13 | E-GEOD-76805 | biostudies-arrayexpress
Project description:Excitatory synapses occur mainly on dendritic spines, and spine density is usually correlated with the strength of excitatory synaptic transmission. We report that Nr4a1, an activity-inducible gene encoding a nuclear receptor, regulates the density and distribution of dendritic spines in CA1 pyramidal neurons. Nr4a1 overexpression resulted in elimination of the majority of spines; however, postsynaptic densities were preserved on dendritic shafts, and the strength of excitatory synaptic transmission was unaffected, showing that excitatory synapses can be dissociated from spines. mRNA expression profiling studies suggest that Nr4a1-mediated transcriptional regulation of the actin cytoskeleton contributes to this effect. Under conditions of chronically elevated activity, when Nr4a1 was induced, Nr4a1 knockdown increased the density of spines and PSDs specifically at the distal ends of dendrites. Thus, Nr4a1 is a key component of an activity-induced transcriptional program that regulates the density and distribution of spines and synapses.
2016-01-13 | GSE76805 | GEO
Project description:FUS is a primarily nuclear RNA-binding protein with important roles in RNA processing and transport. FUS mutations disrupting its nuclear localization characterize a subset of amyotrophic lateral sclerosis (ALS-FUS) patients, through an unidentified pathological mechanism. FUS regulates nuclear RNA, but its role at the synapse is poorly understood. Here, we used super-resolution imaging to determine the physiological localization of extranuclear, neuronal FUS and found it predominantly near the vesicle reserve pool of presynaptic sites. Using CLIP-seq on synaptoneurosome preparations, we identified synaptic RNA targets of FUS that are associated with synapse organization and plasticity. Synaptic FUS was significantly increased in a knock-in mouse model of ALS-FUS, at presymptomatic stages. Despite apparently unaltered synaptic organization, RNA-seq of synaptoneurosomes highlighted age-dependent dysregulation of glutamatergic and GABAergic synapses. Our study indicates that FUS relocalization to the synapse in early stages of ALS-FUS results in synaptic impairment, potentially representing an initial trigger of neurodegeneration.
2021-03-05 | E-MTAB-10104 | biostudies-arrayexpress
Project description:Gene expression profiles of Ngn3-overexpressing cultured hippocampal neurons was compared to the profile of the corresponding control populations. (neurons expressing GFP). Neurogenin3, a proneural transcription factor controlled by Notch receptor, is involved in hippocampal neuron differentiation and synapses, but little is known about the molecular bases of Ngn3 activity in neurons. Microarray analysis indicated that overexpression of Ngn3 upregulated a number of genes related with cytoskeleton dynamics. One of then was Fmn1 whose protein is associated with actin and microtubule cytoskeleton. Overexpression of the isoform Fmn1-Ib in cultured hippocampal neurons induced an increase in the number of primary dendrites and in the number of glutamatergic synaptic inputs without affecting GABAergic synapses resulting in a modification in the balance between excitation and inhibition. The same changes were provoked by overexpression of Ngn3. In addition downregulation of Fmn1 by the use of Fmn1-siRNAs impaired such morphological and synaptic changes induced by Ngn3 overexpression in neurons. These results reveal a previously unknown involvement of Formin1 in dendritic and synaptic plasticity as a key protein in the Nng3 signaling pathway that contributes to understanding of molecular mechanisms of the neuronal differentiation. Cultured hippocampal neurons were transduced using Sindbis virus bearing myc-tagged Ngn3 or GFP as control. Cells were lysed and total RNA was extracted.Gene expression profiles were obtained for each sample and compared
2011-01-27 | E-GEOD-26911 | biostudies-arrayexpress
Project description:Synapses are the regions of the neuron that enable the transmission and propagation of action potentials on the cost of high energy consumption and elevated demand for mitochondrial ATP production. The rapid changes in local energetic requirements at dendritic spines implies the role of mitochondria in the maintenance of their homeostasis. We have employed quantitative mass spectrometry and in vitro stimulation of isolated mouse synaptoneurosomes to create a comprehensive view of local protein synthesis in neurons. Strikingly, the second most numerus group of proteins synthetized in the synapses represented ones imported into the mitochondria. The proteomic data were further supported by sequencing of mRNAs bound with actively translating polyribosomes. Our results show that an important pool of mitochondrial proteins is locally produced at the synapse indicting that mitochondrial biogenesis take place locally in order to maintain the pool of functional mitochondria in axons and dendrites. We further show that stimulation of synaptoneurosomes induce the local synthesis of mitochondrial proteins that are transported to the mitochondria and incorporated into the protein supercomplexes of respiratory chain. This contributes to mitochondrial biogenesis in neurons and a logical consequence of this fact would be a dysregulation of mitochondrial function in the conditions that deal with dysregulated synaptic translation, such as fragile X syndrome. Indeed, we have shown mitochondrial dysfunction in synapses of Fmr1 KO mice.
2020-04-14 | GSE122724 | GEO
Project description:Even though neuronal and cancer cells have quite different purposes in the body, there is growing evidence that metastatic cancer cells implement signaling mechanisms found in homeostasis of synaptic growth/plasticity. Recent studies have highlight some remarkable similarities in both form and function of these two unique cell type. The p140Cap adaptor protein is an example of a mo-lecular hub that controls cancer cell migration and invasion through regulating protein complexes at cellular adhesions. Moreover, p140Cap in neurons is likely very important for normal brain function-ing, as it works as scaffold in postsynaptic signal transmission complexes and regulates F-actin re-modelling, which results in neuron dendritic spines synaptic plasticity It recruits and regulates signaling molecules both in breast cancer cells and in healthy neuronal synapses.
2019-09-25 | PXD008778 | Pride
Project description:Hippocampal synaptic plasticity is important for learning and memory formation. Homeostatic synaptic plasticity is a specific form of synaptic plasticity that is induced upon prolonged changes in neuronal activity to maintain network homeostasis. While astrocytes are important regulators of synaptic transmission and plasticity, it is largely unclear how they interact with neurons to regulate synaptic plasticity at the circuit level. Here, we show that neuronal activity blockade selectively increases the expression and secretion of IL-33 (interleukin-33) by astrocytes in the hippocampal cornu ammonis 1 (CA1) subregion. This IL-33 stimulates an increase in excitatory synapses and neurotransmission through the activation of neuronal IL-33 receptor complex and synaptic recruitment of the scaffold protein PSD-95. We found that acute administration of tetrodotoxin in hippocampal slices or inhibition of hippocampal CA1 excitatory neurons by optogenetic manipulation increases IL-33 expression in CA1 astrocytes. Furthermore, IL-33 administration in vivo promotes the formation of functional excitatory synapses in hippocampal CA1 neurons, whereas conditional knockout of IL-33 in CA1 astrocytes decreases the number of excitatory synapses therein. Importantly, blockade of IL-33 and its receptor signaling in vivo by intracerebroventricular administration of its decoy receptor inhibits homeostatic synaptic plasticity in CA1 pyramidal neurons and impairs spatial memory formation in mice. These results collectively reveal an important role of astrocytic IL-33 in mediating the negative-feedback signaling mechanism in homeostatic synaptic plasticity, providing insights into how astrocytes maintain hippocampal network homeostasis.
2020-12-14 | GSE161540 | GEO
Project description:This is an SBML version of the model described in: A kinetic model of dopamine- and calcium-dependent striatal synaptic plasticity.
Nakano T, Doi T, Yoshimoto J, Doya K. PLoS Comput Biol. 2010 Feb 12;6(2):e1000670. PMID: 20169176
; DOI: 10.1371/journal.pcbi.1000670
Abstract:
Corticostriatal synapse plasticity of medium spiny neurons is regulated by glutamate input from the cortex and dopamine input from the substantia nigra. While cortical stimulation alone results in long-term depression (LTD), the combination with dopamine switches LTD to long-term potentiation (LTP), which is known as dopamine-dependent plasticity. LTP is also induced by cortical stimulation in magnesium-free solution, which leads to massive calcium influx through NMDA-type receptors and is regarded as calcium-dependent plasticity. Signaling cascades in the corticostriatal spines are currently under investigation. However, because of the existence of multiple excitatory and inhibitory pathways with loops, the mechanisms regulating the two types of plasticity remain poorly understood. A signaling pathway model of spines that express D1-type dopamine receptors was constructed to analyze the dynamic mechanisms of dopamine- and calcium-dependent plasticity. The model incorporated all major signaling molecules, including dopamine- and cyclic AMP-regulated phosphoprotein with a molecular weight of 32 kDa (DARPP32), as well as AMPA receptor trafficking in the post-synaptic membrane. Simulations with dopamine and calcium inputs reproduced dopamine- and calcium-dependent plasticity. Further in silico experiments revealed that the positive feedback loop consisted of protein kinase A (PKA), protein phosphatase 2A (PP2A), and the phosphorylation site at threonine 75 of DARPP-32 (Thr75) served as the major switch for inducing LTD and LTP. Calcium input modulated this loop through the PP2B (phosphatase 2B)-CK1 (casein kinase 1)-Cdk5 (cyclin-dependent kinase 5)-Thr75 pathway and PP2A, whereas calcium and dopamine input activated the loop via PKA activation by cyclic AMP (cAMP). The positive feedback loop displayed robust bi-stable responses following changes in the reaction parameters. Increased basal dopamine levels disrupted this dopamine-dependent plasticity. The present model elucidated the mechanisms involved in bidirectional regulation of corticostriatal synapses and will allow for further exploration into causes and therapies for dysfunctions such as drug addiction.
The model was encoded from the supplemental material accompanying the article.
The stimuli used in the article are hard to implement in SBML, so right now the model does not reproduce the results given in the article. Originally created by libAntimony v1.4 (using libSBML 3.4.1)This model originates from BioModels Database: A Database of Annotated Published Models (http://www.ebi.ac.uk/biomodels/). It is copyright (c) 2005-2011 The BioModels.net Team.
To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication
for more information. In summary, you are entitled to use this encoded model in absolutely any manner you deem suitable, verbatim, or with modification, alone or embedded it in a larger context, redistribute it, commercially or not, in a restricted way or not..
To cite BioModels Database, please use: Li C, Donizelli M, Rodriguez N, Dharuri H, Endler L, Chelliah V, Li L, He E, Henry A, Stefan MI, Snoep JL, Hucka M, Le Novère N, Laibe C (2010) BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models. BMC Syst Biol., 4:92.
2005-01-01 | MODEL1101170000 | BioModels
Project description:Many forms of synaptic plasticity are critically dependent upon production of cGMP to trigger activity-dependent increases in synaptic size and strength. Phosphodiesterase 9A (PDE9A) is a high affinity, cGMP-specific phosphodiesterase with widespread distribution in the central nervous system. Inhibition of PDE9A results in significant accumulation of cGMP in brain tissue and cerebrospinal fluid (CSF) of rodents, and increases CSF cGMP in human volunteers. We hypothesized that chronic exposure to a PDE9A inhibitor, and the associated elevations in brain cGMP could provide a therapeutic benefit to vulnerable synapses chronically exposed to Aβ in transgenic mice over-expressing human mutant amyloid precursor protein (Tg2576 mice). A total of N=20 animals per group of 4 month old Tg2576 mice and non-transgenic littermates (WT) were implanted with Alzet osmotic minipumps to deliver vehicle or the PDE9A inhibitor PF-04447943. Neurobehavioral outcomes were measured as conditioned fear response after 28 days of treatment and subsequently brains were harvested for measurement of Aβ, gene expression profiling or synaptic density as assessed by Golgi staining of dendrites. Dendritic spine density on apical dendrites of CA1 neurons exhibited a small but significant deficit in the density of dendritic spines in vehicle treated Tg2576 mice as compared to WT mice. This deficit was ameliorated by 30 days of exposure to PF-04447943. No significant drug effect was observed in WT mice. No significant effects of drug treatment were observed on Aβ levels in Tg2576 mice. Behavioral analysis of Tg2576 mice showed deficits in fear conditioning as early as 2 months old, and therefore were considered unlikely to be due to the accumulation of oligomeric Aβ. These deficits were not affected by drug treatment. Transcriptional profiles of Tg2576 mice treated with drug compared to vehicle showed evidence of regulation of pathways related to synaptic plasticity and remodeling of the dendritic cytoskeleton, consistent with stabilization of vulnerable spine structure. These data supports the hypothesis that PDE9A inhibition can stabilize vulnerable synapses early in the Alzheimer’s disease process. 4-month old Tg2576 mice and non-transgenic (WT) littermates were implanted with minipumps to deliver vehicle or the PDE9A-inhibitor, PF-04447943, for 28 days. At the end of the study, hippocampus and frontal cortex were dissected from n=8 mice per group, RNA was isolated, and hybridized to Affymetrix 430 2.0 mouse whole genome microarray.
2012-03-09 | E-GEOD-36237 | biostudies-arrayexpress
Project description:The nervous system plays an increasingly appreciated role in the regulation of cancer. In gliomas, neuronal activity drives tumor progression through paracrine signaling factors such as neuroligin-3 and brain-derived neurotrophic factor (BDNF), and also through electrophysiologically functional neuron-to-glioma synapses mediated by AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptors. The consequent glioma cell membrane depolarization drives tumor proliferation. In the healthy brain, activity-regulated secretion of BDNF promotes adaptive plasticity of synaptic connectivity and strength. Here, we show that malignant synapses exhibit similar plasticity regulated by BDNF. Signaling through the receptor TrkB (tropomyosin receptor kinase B), BDNF promotes AMPA receptor trafficking to the glioma cell membrane, resulting in increased amplitude of glutamate-evoked currents in the malignant cells. This potentiation of malignant synaptic strength shares mechanistic features with synaptic plasticity that contributes to memory and learning in the healthy brain. BDNF-TrkB signaling also regulates the number of neuron-to-glioma synapses. Abrogation of activity-regulated BDNF secretion from the brain microenvironment or loss of TrkB in human glioma cells robustly inhibits tumor progression. Blocking TrkB genetically or pharmacologically abrogates these effects of BDNF on glioma synapses and substantially prolongs survival in xenograft models of pediatric glioblastoma and diffuse intrinsic pontine glioma (DIPG). Taken together, these findings indicate that BDNF-TrkB signaling promotes malignant synaptic plasticity and augments tumor progression.
2023-03-01 | GSE222481 | GEO