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Astrocyte-encoded positional cues maintain sensorimotor circuit integrity

ABSTRACT: Astrocytes, the most abundant cells in the central nervous system, promote synapse formation and help refine neural connectivity. Although they are allocated to spatially distinct regional domains during development, it is unknown whether region-restricted astrocytes are functionally heterogeneous. Here we show that postnatal spinal cord astrocytes express several region-specific genes, and that ventral astrocyte-encoded Semaphorin3a (Sema3a) is required for proper motor neuron and sensory neuron circuit organization. Loss of astrocyte-encoded Sema3a led to dysregulated α−motor neuron axon initial segment orientation, markedly abnormal synaptic inputs, and selective death of α−but not of adjacent γ−motor neurons. Additionally, a subset of TrkA+ sensory afferents projected to ectopic ventral positions. These findings demonstrate that stable maintenance of a positional cue by developing astrocytes influences multiple aspects of sensorimotor circuit formation. More generally, they suggest that regional astrocyte heterogeneity may help to coordinate postnatal neural circuit refinement.

ORGANISM(S): Mus musculus

PROVIDER: GSE55054 | GEO | 2014/05/02

SECONDARY ACCESSION(S): PRJNA238347

REPOSITORIES: GEO

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Astrocyte-encoded positional cues maintain sensorimotor circuit integrity

Project description:Astrocytes, the most abundant cells in the central nervous system, promote synapse formation and help refine neural connectivity. Although they are allocated to spatially distinct regional domains during development, it is unknown whether region-restricted astrocytes are functionally heterogeneous. Here we show that postnatal spinal cord astrocytes express several region-specific genes, and that ventral astrocyte-encoded Semaphorin3a (Sema3a) is required for proper motor neuron and sensory neuron circuit organization. Loss of astrocyte-encoded Sema3a led to dysregulated α−motor neuron axon initial segment orientation, markedly abnormal synaptic inputs, and selective death of α−but not of adjacent γ−motor neurons. Additionally, a subset of TrkA+ sensory afferents projected to ectopic ventral positions. These findings demonstrate that stable maintenance of a positional cue by developing astrocytes influences multiple aspects of sensorimotor circuit formation. More generally, they suggest that regional astrocyte heterogeneity may help to coordinate postnatal neural circuit refinement. 12 total samples consisting of three biological replicates each of flow sorted postnatal day 7 dorsal spinal cord astrocytes, ventral spinal cord astrocytes, dorsal SC non astrocytes, and ventral SC non astrocytes

2014-05-02 | E-GEOD-55054 | biostudies-arrayexpress

Astrocyte allocation during brain development is controlled by Tcf4-mediated fate restriction

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2018-05-01 | GSE111148 | GEO

FUS-ALS hiPSC-derived astrocytes impair human motor units through both gain-of-toxicity and loss-of-support mechanisms

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2023-01-19 | GSE196219 | GEO

Perturbations of the proteome in primary astrocytes from the hSOD1(G93A) ALS mouse model

Project description:Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease whose pathophysiology is largely unknown. Despite motor neuron death is recognized as the key event in ALS, astrocytes dysfunctionalities and neuroinflammation were demonstrated to accompany and probably even drive motor neuron loss. Nevertheless, the mechanisms priming astrocyte failure and hyperactivation are still obscure. In this work, altered pathways in ALS astrocytes were unveiled by investigating the proteomic profile of primary spinal-cord astrocytes derived from transgenic ALS mouse model overexpressing the human (h)SOD1(G93A) protein, in comparison with the transgenic counterpart expressing hSOD1(WT) protein. In this research, we showed that hSOD1(G93A) astrocytes present a profound alterations in the expression of proteins involved in proteostasis and glutathione metabolism.

2022-02-17 | PXD026576 | Pride

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Project description:Traumatic axonal injury (TAI) in the brainstem carries a particularly poor prognosis. Although the role of neuroinflammation in this process is incompletely characterized, astrogliosis has been shown to coincide with TAI. Moreover, astrogliotic forebrain astrocytes were recently shown to confer a toxic effect on neurons. We sought to assess if ventral brainstem- or rostroventral spinal astrocytes exert similar effects on motor neurons in vitro. We derived brainstem/rostroventral spinal astrocyte-like cells (ES-astrocytes) and motor neurons using directed differentiation of embryonic stem cells (ES). ES-astrocyte identity was assessed using RNA-sequencing, immunocytochemistry, and comparison with primary subventricular zone-astrocytes. We activated the ES-astrocytes using the neurotoxicity-eliciting cytokines interleukin- (IL-) 1α and tumor necrosis factor-(TNF-)α. In co-cultures with reactive ES-astrocytes and motor neurons, we demonstrated neurotoxic ES-astrocyte activity, similarly to what has previously been shown for other central nervous system (CNS) regions. When exposed to IL-1β and IL-6, two neuroinflammatory cytokines found in the cerebrospinal fluid and serum proteome following severe traumatic brain injury (TBI), ES-astrocytes exerted similar effects on motor neurons. This demonstrates that ventral brainstem and rostroventral spinal cord astrocytes can exert neurotoxic effects in vitro. This highlights the importance of neuroinflammation as a secondary injury mechanism following neurotrauma, and presents a possible treatment avenue to improve neuronal survival in particularly vulnerable CNS regions following TAI.

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2019-05-07 | GSE130763 | GEO

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