Non-linear heterochronic scaling of neurogenesis for species-specific dosing of cortical excitatory subtypes
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PROVIDER: PRJNA1211631 | ENA |
REPOSITORIES: ENA
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Project description:All animals have specialized brain structures with a neuronal composition optimized for their survival and adaptation. The mammals share the laminar structure of the cerebral cortex, where a certain repertoire of excitatory neuron subtypes is arranged in specific tangential layers. However, the quantitative balance of subtypes is highly specialized in each species due to unknown developmental mechanisms. It is of particular interest to understand how the relatively conserved process of mammalian corticogenesis is modified in each species to achieve an optimized neuronal composition. Here, we show that fine-tuning the temporal progression of neurogenesis is the critical mechanism of the species-specific neuronal repertoire through our comparative study of mouse and rat cortical excitatory neurogenesis. Clonal tracing of individual progenitors revealed that rats produce more deep layer (DL) subtypes than mice, but both species produce essentially the same number of upper layer (UL) neurons. Such subtype-specific dosage optimization is mediated by the selective expansion of the early neurogenetic window for DL production in rats, as revealed by our neuronal birthdating and single cell transcriptomics. We found that the temporal neurogenetic status of the progenitors is encoded, at least in part, by Ccnd1 expression, as evidenced by the precocious UL production upon Ccnd1 knockdown in the rat mid-neurogenetic phase, when significant expression is maintained at levels comparable to the earlier phase in mice. Collectively, these results suggest that the closely related rodents, mouse and rat, construct their cortical structure with specific neuronal composition through the pinpointed specialization in developmental progression while maintaining the basic framework of the inside-out sequence of cortical excitatory neurogenesis. This study used mice and rats, the most common laboratory mammals with a close evolutionary relationship, to reveal the detailed molecular and cellular mechanisms behind the fine-tuning of cell composition in the cerebral cortex. Such a detailed comparison dissected the specialized and unchanged processes of corticogenesis during the evolutionary divergence of the two species. This further provides insights into the evolvability and developmental constraints of mammalian corticogenesis.
2025-01-21 | GSE287210 | GEO
Project description:Homeostatic synaptic plasticity (HSP) is a fundamental neuronal mechanism that allows networks to compensate for prolonged changes in activity by adjusting synaptic strength. This process is crucial for maintaining stable brain function and has been implicated in memory consolidation during sleep. While scaling of both excitatory and inhibitory synapses plays an important role during homeostatic synaptic plasticity, molecules coordinating both of these processes are unknown. In this study, we investigate the role of miR-218-5p as a regulator of inhibitory and excitatory synapses in the context of picrotoxin (PTX)-induced homeostatic synaptic downscaling (HSD) in rat hippocampal neurons. Using enrichment analysis of miRNA-binding sites in differentially expressed genes changing upon PTX-induced HSD, we bioinformatically predicted and experimentally validated increased miR-218-5p activity upon PTX-treatment in the process compartment. By monitoring synapse structure in vitro with confocal microscopy, we demonstrate that miR-218-5p exerts a dual effect in HSD: it prevents the downscaling of excitatory synapses and dendritic spines, while at the same time blocking inhibitory synapse upscaling. Furthermore, we identify the Neuroligin2 interacting molecule Mdga1 as a crucial target of miR-218-5p in the context of homeostatic upscaling of inhibitory synapses. By performing long-term electroencephalographic (EEG) recordings, we further revealed that local inhibition of miR-218-5p in the somatosensory cortex reduced local slow-wave activity (SWA) during non-rapid-eye-movement (NREM) sleep. In summary, this study uncovers miR-218-5p as a key player in coordinating inhibitory and excitatory synapses during homeostatic plasticity and sleep. Our findings contribute to a deeper understanding of how neural circuits maintain stability in the face of activity-induced perturbations, with potential implications for both physiological and pathological conditions.
2025-03-17 | GSE245158 | GEO
Project description:microRNA-218-5p Coordinates Scaling of Excitatory and Inhibitory Synapses during Homeostatic Synaptic Plasticity
| PRJNA1027270 | ENA
Project description:Homeostatic scaling is a global form of synaptic plasticity used by neurons to adjust overall synaptic weight and maintain neuronal firing rates while protecting information coding. While homeostatic scaling has been demonstrated in vitro, a clear physiological function of this plasticity type has not been defined. Sleep is an essential process that modifies synapses to support cognitive functions such as learning and memory. Evidence suggests that information coding during wake drives synapse strengthening which is offset by weakening of synapses during sleep .Here we use biochemical fractionation, proteomics and in vivo two-photon imaging to characterize wide-spread changes in synapse composition in mice through the wake/sleep cycle. We find that during the sleep phase, synapses are weakened through dephosphorylation and removal of synaptic AMPA-type glutamate receptors (AMPARs) driven by the immediate early gene Homer1a and signaling from group I metabotropic glutamate receptors (mGluR1/5), consistent with known mechanisms of homeostatic scaling-down in vitro. Further, we find that these changes are important in the consolidation of contextual memories. While Homer1a gene expression is driven by neuronal activity during wake, Homer1a protein targeting to synapses serves as an integrator of arousal and sleep need through signaling by the wake-promoting neuromodulator noradrenaline (NA) and sleep-promoting modulator adenosine. During sleep or periods of increased sleep need Homer1a enters synapses where it remodels mGluR1/5 signaling complexes to promote AMPAR removal. Thus, we have characterized widespread changes occurring at synapses through the wake/sleep cycle and demonstrated that known mechanisms of homeostatic scaling-down previously demonstrated only in vitro are active in the brain during sleep to remodel synapses, contributing to memory consolidation.
2017-02-13 | PXD004537 | Pride
Project description:Synaptic scaling is a form of homeostatic plasticity which allows neurons to reduce their action potential firing rate in response to chronic alterations in neural activity. Synaptic scaling requires profound changes in gene expression, but the relative contribution of local and cell-wide mechanisms to synaptic scaling is controversial. Here we performed a comprehensive multi-omics characterization of the somatic and process compartments of primary rat hippocampal neurons during synaptic scaling. Thereby, we uncovered highly compartment-specific and correlated changes in the neuronal transcriptome and proteome. Specifically, we identified highly compartment-specific downregulation of crucial regulators of neuronal excitability and excitatory synapse structure. Motif analysis further suggests an important role for trans-acting post-transcriptional regulators, including RNA-binding proteins and microRNAs, in the local regulation of the corresponding mRNAs. Altogether, our study indicates that compartmentalized gene expression changes are widespread in synaptic scaling and might co-exist with neuron-wide mechanism to allow synaptic computation and homeostasis.
2021-07-06 | GSE155540 | GEO
Project description:A clinical study evaluating the dosing of an oral HDACi panobinostat in patient infected with HIV-1. Dosing was 20 mg orally, 3 times weekly, every other week for a total of 8 weeks. Gene expression was evaluated in whole PBMCs at baseline (Visit 2), after 3 doses (Visit 4), 4 weeks after dosing (Visit 12) and 6 months after dosing (Visit 13) using the Affymetrix HTA 2.0 gene expression chip
2018-01-30 | GSE109792 | GEO
Project description:This SuperSeries is composed of the following subset Series: GSE24770: Heterochronic Evolution Reveals Modular Timing Changes in Budding Yeast Transcriptomes (Mutation Accumulation Lines) GSE24771: Heterochronic Evolution Reveals Modular Timing Changes in Budding Yeast Transcriptomes (Natural Strain Timecourse) Refer to individual Series
2010-10-19 | E-GEOD-24772 | biostudies-arrayexpress
Project description:Neuronal networks are subject to fluctuations in both the magnitude and frequency of inputs, requiring plasticity mechanisms to stabilize network activity. Homeostatic synaptic scaling is a form of synaptic plasticity that adjusts the strength of neuronal connections up or down in response to large changes in input. Although homeostatic plasticity requires changes in gene expression, there is only limited data describing the molecular changes associated with homeostatic scaling, focusing mostly on the expression mechanisms involving glutamate receptors. The fact that neuronal networks can be scaled up (in response to reduced activity) or down (in response to enhanced activity) provides a unique opportunity to examine the molecular and proteomic response to opposite ends of the phenotypic spectrum of synaptic plasticity. Here we first demonstrate that homeostatic scaling required protein synthesis. We then examined the plasticity-induced changes in the newly-synthesized neuronal proteome of neurons to identify the landscape of proteomic changes that contribute to opposing forms of homeostatic plasticity. Cultured rat hippocampal neurons (21 DIV) underwent homeostatic upscaling or downscaling (treatments with TTX and Bicucculine, respectively). We used BONCAT (BioOrthogonal Non-Canonical Amino acid Tagging) to metabolically label, capture and identify newly-synthesized proteins, detecting and analysing 5940 newly-synthesized proteins using liquid chromatography-coupled tandem mass spectrometry and label-free quantitation. Neither up- or down-scaling produced changes in the number of different proteins translated. Rather, our findings indicate that synaptic up- and down-scaling elicit opposing translational regulation of several molecular pathways, producing targeted adjustments in the neuronal proteome. We detected ~ 300 differentially regulated proteins involved in neurite outgrowth, reorganization of nerve terminals, axon guidance and targeting, neurotransmitter transport, filopodia assembly, excitatory synapses and glutamate receptor complexes. These proteins include well-characterized mediators of synaptic plasticity, e.g. the ionotropic glutamate receptor complex that is down-regulated during down-scaling and coordinately upregulated during upscaling. We also identified differentially regulated proteins that in addition to their regulation in homeostatic plasticity, are also associated with multiple diseases and disorders, including intellectual disability, schizophrenia, epilepsy, and Parkinson’s disease.
2016-12-22 | PXD004889 | Pride
Project description:NPTX2, Homeostatic Scaling, and Schizophrenia
| PRJNA633132 | ENA
Project description:Gene Expression during Panobinostat Dosing
| PRJNA432059 | ENA