Primary cilia safeguard cortical neurons in neonatal mouse forebrain from environmental stress-induced dendritic degeneration

The developing brain is under the risk of exposure to a multitude of environmental stressors. While perinatal exposure to excessive levels of environmental stress is responsible for a wide spectrum of neurological and psychiatric conditions, the developing brain is equipped with intrinsic cell protection, the mechanisms of which remain unknown. Here we show, using neonatal mouse as a model system, that primary cilia, hair-like protrusions from the neuronal cell body, play an essential role in protecting immature neurons from the negative impacts of exposure to environmental stress. More specifically, we found that primary cilia prevent the degeneration of dendritic arbors upon exposure to alcohol and ketamine, two major cell stressors, by activating cilia-localized insulin-like growth factor 1 receptor and downstream Akt signaling. We also found that activation of this pathway inhibits Caspase-3 activation and caspase-mediated cleavage/fragmentation of cytoskeletal proteins in stress-exposed neurons. These results indicate that primary cilia play an integral role in mitigating adverse impacts of environmental stressors such as drugs on perinatal brain development.

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Rat Reactive Astrocyte Marker (IFAP-70/280KD) is Expressed in Rat Spinal Cord Motor Neurons Following Transection of Sciatic Nerve.

Microscopy and Microanalysis ◽

10.1017/s1431927600007686 ◽

1997 ◽

Vol 3 (S2) ◽

pp. 159-160

Author(s):

V. Kriho ◽

G.D. Pappas ◽

N. Lieska ◽

C.-M. Wu ◽

H.-Y. Yang

Keyword(s):

Motor Neurons ◽

Neuronal Cell ◽

Dynamic Structure ◽

Cytoskeletal Proteins ◽

Neuronal Cell Body ◽

Transport Systems ◽

Major Constituent ◽

Efficient Operation ◽

Associated Proteins ◽

The Subject

Following injury to peripheral nerves, processes involved in regeneration must be activated, restoring the original architecture and synaptic connections of the neuron. This is essential for the efficient operation of the sophisticated communications network of the nervous system. In order to accomplish these tasks, complex changes occur in gene expression. Regenerating neurons shift into a growth mode wherein large amounts of cytoskeletal proteins and other growth-associated proteins are produced. These materials, which are synthesized and produced in the neuronal cell body, are then transferred to the axon via axonal transport systems. Among the cytoskeletal and associated proteins upregulated following injury to the CNS are actin, tubulin and the intermediate filament-associated protein, IFAP-70/280kD. The latter is the subject of this investigation.Intermediate filaments (IF) are a major constituent of the cytoskeleton of most eukaryotic cells. The IF cytoskeleton is a highly dynamic structure that reorganizes continuously as the cell divides and changes shape in response to its environment.

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BDNF/TrkB mediates long-distance dendritic growth by activating CREB/PI3K-mTOR-dependent translation in neuronal cell bodies

10.1101/2020.08.22.262923 ◽

2020 ◽

Author(s):

G Moya-Alvarado ◽

F.C Bronfman

Keyword(s):

Cortical Neurons ◽

Dendritic Growth ◽

Neuronal Cell ◽

Protein Translation ◽

Dendritic Arborization ◽

Neuronal Morphology ◽

Neuronal Cell Body ◽

Long Distance ◽

Bdnf Signaling

ABSTRACTBrain-Derived Neurotrophic Factor (BDNF) is broadly expressed in many circuits of the central nervous system (CNS). It binds TrkB and p75 to trigger different signaling pathways, including ERK1/2 and PI3K-mTOR, to induce dendritic growth and synaptic plasticity. When binding to BDNF, TrkB and p75 are endocytosed to signaling endosomes to continue signaling inside the cell. Whether BDNF/TrkB-p75 signaling endosomes in axons are regulating long-distance signaling in cell bodies to modify neuronal morphology is unknown. Here, we studied the functional role of BDNF signaling endosomes in long-distance regulation of dendritic growth using compartmentalized cultures of rat and mouse cortical neurons derived from p75exonIII knock-out or TrkBF616A knock-in mice. By applying BDNF to distal axons, we showed the capacity of axonal BDNF to increase dendritic arborization in cell bodies. This process depended on TrkB activity, but not p75 expression. In axons, BDNF/TrkB co-localized with Rab5 endosomes and increased active Rab5. Also, dynein was required for BDNF long-distance signaling, consistent with sorting and transport of signaling endosomes. Using neurons derived from TrkBF616A knock-in mice and the 1NM-PP1 inhibitor, we were able to demonstrate that TrkB receptors activated in the axons by BDNF, were required in the neuronal cell body to increase TrkB activity and phosphorylation of CREB. Also, we were able to visualize endosomes containing activated TrkB. PI3K activity was not required in the axons for dynein dependent BDNF responses. However, dendritic arborization induced by axonal BDNF signaling required both nuclear CREB and PI3K activation in cell bodies. Consistently, axonal BDNF increased protein translation in cell bodies and CREB and PI3K and mTOR activity were required for this process. Altogether, these results show that BDNF/TrkB signaling endosomes generated in axons allows long-distance control of dendritic growth coordinating both transcription and protein translation. Our results suggest a role of BDNF-TrkB signaling endosomes wiring circuits in the CNS.

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Rapidly transported organelles containing membrane and cytoskeletal components: their relation to axonal growth.

The Journal of Cell Biology ◽

10.1083/jcb.105.6.2827 ◽

1987 ◽

Vol 105 (6) ◽

pp. 2827-2835 ◽

Cited By ~ 64

Author(s):

P J Hollenbeck ◽

D Bray

Keyword(s):

Cell Body ◽

Growth Cone ◽

Neuronal Cell ◽

Axonal Growth ◽

Culture Conditions ◽

Cytoskeletal Proteins ◽

Neuronal Cell Body ◽

Neurofilament Protein ◽

Anterograde Transport ◽

Fourfold Increase

We have examined the movements, composition, and cellular origin of phase-dense varicosities in cultures of chick sympathetic and sensory neurons. These organelles are variable in diameter (typically between 0.2 and 2 microns) and undergo saltatory movements both towards and away from the neuronal cell body. Their mean velocities vary inversely with the size of the organelle and are greater in the retrograde than the anterograde direction. Organelles stain with the lipophilic dye 1, 1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanine and with antibodies to cytoskeletal components. In cultures double-stained with antibodies to alpha-tubulin and 70-kD neurofilament protein (NF-L), approximately 40% of the organelles stain for tubulin, 30% stain for NF-L, 10% stain for both tubulin and NF-L, and 40% show no staining with either antibody. The association of cytoskeletal proteins with the organelles shows that these proteins are able to move by a form of rapid axonal transport. Under most culture conditions the predominant direction of movement is towards the cell body, suggesting that the organelles are produced at or near the growth cone. Retrograde movements continue in culture medium lacking protein or high molecular mass components and increase under conditions in which the advance of the growth cone is arrested. There is a fourfold increase in the number of organelles moving retrogradely in neurites that encounter a substratum-associated barrier to elongation; retrograde movements increase similarly in cultures exposed to cytochalasin at levels known to block growth cone advance. No previously described organelle shows behavior coordinated with axonal growth in this way. We propose that the organelles contain membrane and cytoskeletal components that have been delivered to the growth cone, by slow or fast anterograde transport, in excess of the amounts required to synthesize more axon. In view of their rapid mobility and variable contents, we suggest that they be called "neuronal parcels."

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Fructose-1,6-biphosphate prevents excitotoxic neuronal cell death in the neonatal mouse brain

Developmental Brain Research ◽

10.1016/s0165-3806(02)00615-6 ◽

2003 ◽

Vol 140 (2) ◽

pp. 287-297 ◽

Cited By ~ 23

Author(s):

Marta Rogido ◽

Isabelle Husson ◽

Christine Bonnier ◽

Marie-Christine Lallemand ◽

Claude Mérienne ◽

...

Keyword(s):

Cell Death ◽

Mouse Brain ◽

Neuronal Cell Death ◽

Neuronal Cell ◽

Neonatal Mouse

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Abstract 3115: Low-Level Laser Therapy Protects Against OGD-induced Neurotoxicity Of Primary Cultured Mouse Cortical Neurons

Stroke ◽

10.1161/str.43.suppl_1.a3115 ◽

2012 ◽

Vol 43 (suppl_1) ◽

Author(s):

Zhanyang Yu ◽

Ning Liu ◽

Eng H Lo ◽

Thomas J McCarthy ◽

Xiaoying Wang

Keyword(s):

Laser Therapy ◽

Mitochondrial Function ◽

Cortical Neurons ◽

Neuronal Cell Death ◽

Neuronal Cell ◽

Low Level Laser Therapy ◽

Primary Neurons ◽

Novel Therapy ◽

Low Level ◽

Mtt Reduction

Background: Low level light (or laser) therapy (LLLT) has been studied and practiced for promoting wound healing, reducing pain, inflammation, and ischemic tissue damage. Recently, a series of experimental and clinical investigations have suggested that LLLT may be a novel therapy against hypoxic/ischemic brain damage. A clinical trial of LLLT therapy for ischemic stroke is now on going. However, the molecular mechanism of LLLT-conferred neuroprotection remains poorly defined. In this study, we tested our hypothesis that LLLT may attenuate impairments of mitochondrial function induced by hypoxic/ischemic insults in primary cultured mouse cortical neurons. Method: At day 9 of culture, primary neurons were subjected to 4 hr OGD followed by reoxygenation. One 810-nm LLLT treatment was applied for 2 minutes at 2 hr after reoxygenation. Neurotoxicity was measured after 20 hr after reoxygenation by LDH release assay. We also measured MTT reduction and mitochondria membrane potential (MMP) at 2 hr after LLLT treatment as markers of mitochondrial function. Results: The neurotoxicity study showed that 4 hr OGD plus 20 hr reoxygenation caused 33.8± 3.4% neuronal cell death, while LLLT treatment significantly reduced the neuronal death rate to 23.6± 2.9% (30.2% reduction, n=6, p smaller than 0.05). Mitochondrial functional assays showed OGD decreased MTT reduction to 75.9± 2.68%, but LLLT treatment significantly rescued MTT reduction to 87.6±4.55% (15.4% improvement, n=6, p smaller than 0.05). Furthermore, after OGD, MMP was reduced to 48.9±4.39%, while LLLT treatment significantly ameliorated this reduction to 89.6± 13.9% (83% improvement, n=4, p smaller than 0.05) compared to normoxic controls. Conclusion: The present study suggests that LLLT treatment is protective against OGD-induced neurotoxicity of primary neurons and that this protection may be conferred through preservation or rescue of mitochondrial function.

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Neurotransmission in neonatal rat cardiac ganglion in situ

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1990.259.4.h997 ◽

1990 ◽

Vol 259 (4) ◽

pp. H997-H1005 ◽

Cited By ~ 4

Author(s):

G. R. Seabrook ◽

L. A. Fieber ◽

D. J. Adams

Keyword(s):

Neuronal Cell ◽

Nerve Fibers ◽

Heart Beat ◽

Neonatal Rat ◽

Neuronal Cell Body ◽

High Frequency Stimulation ◽

Excitatory Postsynaptic Potential ◽

Cardiac Ganglion ◽

Cardiac Ganglia

The intrinsic cardiac ganglia of the neonatal rat heart in situ were studied using electrophysiological and histochemical techniques. The vagal branches innervating the atrial myocardium and cardiac ganglia were identified and individual ganglion cells visualized using Hoffman modulation contrast optics. Histochemical studies revealed the presence of acetylcholinesterase activity associated with neuronal cell bodies and fibers, catecholamine-containing, small intensely fluorescent cells, and cell bodies and nerve fibers immunoreactive for vasoactive intestinal polypeptide. Intracellular recordings from the "principal" cells of the rat cardiac ganglion in situ revealed a fast excitatory postsynaptic potential (EPSP) evoked after electrical stimulation of the vagus nerve, which was inhibited by the nicotinic receptor antagonist, mecamylamine. No spontaneously firing neurons were found, although infrequent (less than 2 min-1) spontaneous miniature EPSPs were observed in most neurons. The quantal content of neurally evoked responses was between 10 and 30 quanta, and the presence of multiple EPSPs in some cells suggested polyneuronal innervation. The neurally evoked EPSP amplitude was dependent on the rate of nerve stimulation, decreasing with increasing frequency of stimulation. Neurons exhibited a sustained depolarization during high frequency stimulation (greater than 1 Hz), and in approximately 15% of the cells a slow depolarization lasting 1-3 min was observed after a train of stimuli. The presence of catecholamine- and neuropeptide-containing neuronal cell body fibers in neonatal rat cardiac ganglia in situ, along with neurally evoked postsynaptic responses resistant to cholinergic ganglionic blockers, suggests a role for noncholinergic transmission in the regulation of the mammalian heart beat.

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Separation of a process from the neuronal cell body using a thin aluminum foil separator

Brain Research Protocols ◽

10.1016/s1385-299x(98)00014-2 ◽

1998 ◽

Vol 2 (4) ◽

pp. 352-356 ◽

Cited By ~ 1

Author(s):

Kosuke Noda ◽

Keita Jimbo ◽

Kazuo Suzuki ◽

Kentaro Yoda

Keyword(s):

Cell Body ◽

Neuronal Cell ◽

Aluminum Foil ◽

Neuronal Cell Body ◽

Thin Aluminum ◽

Thin Aluminum Foil

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Differences in splicing defects between the grey and white matter in myotonic dystrophy type 1

10.1101/819433 ◽

2019 ◽

Author(s):

Masamitsu Nishi ◽

Takashi Kimura ◽

Mitsuru Furuta ◽

Koichi Suenaga ◽

Tsuyoshi Matsumura ◽

...

Keyword(s):

White Matter ◽

Myotonic Dystrophy ◽

Cell Body ◽

Neuronal Cell ◽

Neuronal Cell Body ◽

Myotonic Dystrophy Type 1 ◽

Myotonic Dystrophy Type ◽

And Control ◽

The Brain

AbstractMyotonic dystrophy type 1 (DM1) is a multi-system disorder caused by CTG repeats in the myotonic dystrophy protein kinase (DMPK) gene. This leads to sequestration of the splicing factor, muscleblind-like 2 (MBNL2), and aberrant splicing, mainly in the central nervous system. We investigated the splicing patterns of MBNL1/2 and genes controlled by MBNL2 in several regions of the brain and between the grey matter (GM) and white matter (WM) in DM1 patients using RT-PCR. Compared with the control, the percentage of spliced-in parameter (PSI) for most of the examined exons were significantly altered in most of the brain regions of DM1 patients, except for the cerebellum. The splicing of many genes was differently regulated between the GM and WM in both DM1 and control. The level of change in PSI between DM1 and control was higher in the GM than in the WM. The differences in alternative splicing between the GM and WM may be related to the effect of DM1 on the WM of the brain. We hypothesize that in DM1, aberrantly spliced isoforms in the neuronal cell body of the GM may not be transported to the axon. This might affect the WM as a consequence of Wallerian degeneration secondary to cell body damage. Our findings may have implications for analysis of the pathological mechanisms and exploring potential therapeutic targets.

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Cell type resolved co-expression networks of core clock genes in brain development

10.1101/2020.12.30.424790 ◽

2021 ◽

Author(s):

Surbhi Sharma ◽

Asgar Hussain Ansari ◽

Soundhar Ramasamy

Keyword(s):

Circadian Clock ◽

Single Cell ◽

Radial Glia ◽

Clock Genes ◽

Neuronal Cell ◽

Cell Types ◽

Developing Brain ◽

Knock Out

AbstractThe circadian clock regulates vital cellular processes by adjusting the physiology of the organism to daily changes in the environment. Rhythmic transcription of core Clock Genes (CGs) and their targets regulate these processes at the cellular level. Circadian clock disruption has been observed in people with neurodegenerative disorders like Alzheimer’s and Parkinson’s. Also, ablation of CGs during development has been shown to affect neurogenesis in both in vivo and in vitro models. Previous studies on the function of CGs in the brain have used knock-out models of a few CGs. However, a complete catalog of CGs in different cell types of the developing brain is not available and it is also tedious to obtain. Recent advancements in single-cell RNA sequencing (scRNA-seq) has revealed novel cell types and elusive dynamic cell states of the developing brain. In this study by using publicly available single-cell transcriptome datasets we systematically explored CGs-coexpressing networks (CGs-CNs) during embryonic and adult neurogenesis. Our meta-analysis reveals CGs-CNs in human embryonic radial glia, neurons and also in lesser studied non-neuronal cell types of the developing brain.

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6B4 proteoglycan/phosphacan is a repulsive substratum but promotes morphological differentiation of cortical neurons

Development ◽

10.1242/dev.122.2.647 ◽

1996 ◽

Vol 122 (2) ◽

pp. 647-658

Author(s):

N. Maeda ◽

M. Noda

Keyword(s):

Cell Adhesion ◽

Neurite Outgrowth ◽

Cortical Neurons ◽

Tyrosine Phosphatase ◽

Neuronal Cell ◽

Morphological Differentiation ◽

Cell Types ◽

Thalamic Neurons ◽

Neurite Extension ◽

The Brain

6B4 proteoglycan/phosphacan is one of the major phosphate-buffered saline-soluble chondroitin sulfate proteoglycans of the brain. Recently, this molecule has been demonstrated to be an extracellular variant of the proteoglycan-type protein tyrosine phosphatase, PTPzeta (RPTPbeta). The influence of the 6B4 proteoglycan, adsorbed onto the substratum, on cell adhesion and neurite outgrowth was studied using dissociated neurons from the cerebral cortex and thalamus. 6B4 proteoglycan adsorbed onto plastic tissue culture dishes did not support neuronal cell adhesion, but rather exerted repulsive effects on cortical and thalamic neurons. When neurons were densely seeded on patterned substrata consisting of a grid-like structure of alternating poly-L-lysine and 6B4 proteoglycan-coated poly-L-lysine domains, they were concentrated on the poly-L-lysine domains. However, 6B4 proteoglycan did not retard the differentiation of neurons but rather promoted neurite outgrowth and development of the dendrites of cortical neurons, when neurons were sparsely seeded on poly-L-lysine-conditioned coverslips continuously coated with 6B4 proteoglycan. This effect of 6B4 proteoglycan on the neurite extension of cortical neurons was apparent even on coverslips co-coated with fibronectin or tenascin. By contrast, the neurite extension of thalamic neurons was not modified by 6B4 proteoglycan. Chondroitinase ABC or keratanase digestion of 6B4 proteoglycan did not affect its neurite outgrowth promoting activity, but a polyclonal antibody against 6B4 proteoglycan completely suppressed this activity, suggesting that a protein moiety is responsible for the activity. 6B4 proteoglycan transiently promoted tyrosine phosphorylation of an 85x10(3) Mr protein in the cortical neurons, which correlated with the induction of neurite outgrowth. These results suggest that 6B4 proteoglycan/phosphacan modulates morphogenesis and differentiation of neurons dependent on its spatiotemporal distribution and the cell types in the brain.

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