scholarly journals Frizzled3 controls axonal development in distinct populations of cranial and spinal motor neurons

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Zhong L Hua ◽  
Philip M Smallwood ◽  
Jeremy Nathans
Keyword(s):  
Cell Death ◽  
Motor Neurons ◽  
Planar Cell Polarity ◽  
Motor Nerve ◽  
Normal Wave ◽  
Axon Growth ◽  
Axonal Growth ◽  
Cell Complexes ◽  
Developing Neurons

Disruption of the Frizzled3 (Fz3) gene leads to defects in axonal growth in the VIIth and XIIth cranial motor nerves, the phrenic nerve, and the dorsal motor nerve in fore- and hindlimbs. In Fz3−/− limbs, dorsal axons stall at a precise location in the nerve plexus, and, in contrast to the phenotypes of several other axon path-finding mutants, Fz3−/− dorsal axons do not reroute to other trajectories. Affected motor neurons undergo cell death 2 days prior to the normal wave of developmental cell death that coincides with innervation of muscle targets, providing in vivo evidence for the idea that developing neurons with long-range axons are programmed to die unless their axons arrive at intermediate targets on schedule. These experiments implicate planar cell polarity (PCP) signaling in motor axon growth and they highlight the question of how PCP proteins, which form cell–cell complexes in epithelia, function in the dynamic context of axonal growth.

scholarly journals Functional characterization of Neurofilament Light b splicing and misbalance in zebrafish

2020 ◽  
Author(s):  
DL Demy ◽  
ML Campanari ◽  
R Munoz-Ruiz ◽  
HD Durham ◽  
BJ Gentil ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Neuronal Development ◽  
Rna Binding ◽  
De Novo ◽  
Functional Characterization ◽  
Axon Growth ◽  
Motor Deficits ◽  
Neurofilament Light ◽  
Cytoplasmic Inclusions

AbstractNeurofilaments (NFs), a major cytoskeletal component of motor neurons, play a key role in their differentiation, establishment and maintenance of their morphology and mechanical strength. The de novo assembly of these neuronal intermediate filaments requires the presence of the neurofilament light subunit, NEFL, which expression is reduced in motor neurons in Amyotrophic Lateral Sclerosis (ALS). This study used zebrafish as a model to characterize the NEFL homologue neflb, which encodes two different isoforms via splicing of the primary transcript (neflbE4 and neflbE3). In vivo imaging showed that neflb is crucial for proper neuronal development, and that disrupting the balance between its two isoforms specifically affects NF assembly and motor axon growth, with resulting motor deficits. This equilibrium is also disrupted upon partial depletion of TDP-43, a RNA binding protein that is mislocalized into cytoplasmic inclusions in ALS. The study supports interaction of NEFL expression and splicing with TDP-43 in a common pathway, both biologically and pathogenetically.

THE P53 FAMILY MEMBER, P63, REGULATES NEURAL PRECURSOR CELL SURVIVAL DURING CORTICAL DEVELOPMENT

2008 ◽  
Vol 31 (4) ◽  
pp. 8
Author(s):  
Sagar Dugani ◽  
Annie Paquin ◽  
Masashi Fujitani ◽  
David R Kaplan ◽  
Freda D Miller
Keyword(s):  
Cell Death ◽  
Sympathetic Neurons ◽  
Cortical Development ◽  
Cre Recombinase ◽  
Cortical Plate ◽  
P53 Family ◽  
Knock Down ◽  
Developing Neurons

Background: p63, a member of the p53 family of proteins, is involved in the regulation of naturally-occurring apoptosis in sympathetic neurons of the peripheral nervous system. Since data from our laboratory indicated that p63 is also expressed in stem cells and neurons within the developing brain, we hypothesized that p63 is involved in regulating the genesis and survival of developing neurons. Methods: As cortical neurogenesis is initiated at embryonic day 12, we knocked-down p63 levels in isolated murine cortical precursors byusing shRNA against p63 or by transfecting floxed-p63 precursors with Cre recombinase. We performed similar studies in vivo using in uteroelectroporation to express either p63 shRNA or Cre recombinase to acutely knockdown or genetically ablate p63. We then performed immunofluorescence for known markers of apoptosis, cell-division, and differentiation to assess the level of cell death, proliferation and neurogenesis. Results: Knock-down of p63 in vitro resulted in a 2-foldincrease in the death of precursors and neurons, associated with blunted neurogenesis but unaltered precursor proliferation. Coincident knock-down of p63 family members, p53, but not p73, rescued the elevated death suggesting that p63 and p53 antagonize each other to promote survival. Similar results were observed in vivo, where knockdown of p63 caused cell death and a decrease in the proportionof neurons in the cortical plate. Conclusions: These experiments indicate that p63 is required forthe survival of neural precursors and newly-born neurons, and for normal cortical development. Ongoing work will explore the environmental cues that regulate p63 during neurogenesis.

scholarly journals Fructose-a double edged sword for cell death versus differentiation and long-term survival of NSC-34 motor neuron like cells in vitro

2021 ◽  
Author(s):  
Divya Lodha ◽  
Jamuna R. Subramaniam
Keyword(s):  
Cell Proliferation ◽  
Cell Death ◽  
Motor Neurons ◽  
Response Regulator ◽  
Nuclear Staining ◽  
Term Survival ◽  
High Fructose

Abstract In various neurological and neurodegenerative diseases (ND), motor neurons (MN) of the spinal cord are affected leading to movement impairments. The ND, Amyotrophic Lateral Sclerosis (ALS), is caused due to MN degeneration. ALS afflicts athletes and other major sports personalities, who generally consume fructose enriched sports drinks. Recently, we have reported that high fructose (F5%) impairs the metabolic activity in the NSC-34, MN cell line and reduces the healthspan of C. elegans. But how fructose impacts the MNs either in vitro or in vivo in the long term is not understood. Here we report, to our surprise, that high fructose (F5%) treatment of NSC-34 leads to differentiation of 1-2% of cells with progressive neurite extension. They could be maintained for 80 days in vitro with 5% CO2 and O2 at 18.8%. On the contrary, 5% fructose significantly reduced cell viability by ~85% and inhibited cell proliferation by Day10. Nuclear staining displayed multiple nuclei in the cells indicative of cytokinesis inhibition which led to the lack of cell proliferation. Further, F5% significantly increased ROS levels (^~34%), the potential cause for reduced viability. In addition, no induction of expression of the master oxidative stress response regulator, the transcription factor, nrf-2, or the downstream effector, sod1, was evident. Despite the adverse effects, in the absence of any, F5% is a potential strategy to maintain at least a small percentage of MNs for a long time, ~45 days in vitro, which also reinforces the Redox-Cell death versus cell survival conundrum.

scholarly journals The manipulation of spinal motor neuron axonal growth promotes spinal cord repair

2021 ◽  
Author(s):  
Feng Wang ◽  
Xinya Fu ◽  
Meiemei Li ◽  
Xingran Wang ◽  
Jile Xie ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Motor Neurons ◽  
Axonal Regeneration ◽  
Axonal Growth ◽  
Treatment Method ◽  
Spinal Motor Neurons ◽  
Spinal Motor ◽  
Cord Injury ◽  
Spinal Cord Repair

The loss of motor function in patients with spinal cord injury (SCI) is primarily due to the severing of the corticospinal tract (CST). Spinal motor neurons are located in the anterior horn of the spinal cord, and as the lower neurons of the CST, they control voluntary movement. Furthermore, its intrinsic axonal growth ability is significantly stronger than that of cerebral cortex pyramid neurons, which are the upper CST neurons. Therefore, we established an axonal regeneration model of spinal motor neurons to investigate the feasibility of repairing SCI by promoting axonal regeneration of spinal motor neurons. We demonstrated that conditionally knocking out pten in mature spinal motor neurons drastically enhanced axonal regeneration in vivo, and the regenerating axons of the spinal motor neurons re-established synapses with other cells in the damaged spinal cord. Thus, this strategy may serve as a novel and effective treatment method for SCI.

scholarly journals Functional Characterization of Neurofilament Light Splicing and Misbalance in Zebrafish

Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1238
Author(s):  
Doris Lou Demy ◽  
Maria Letizia Campanari ◽  
Raphael Munoz-Ruiz ◽  
Heather D. Durham ◽  
Benoit J. Gentil ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Rna Binding ◽  
De Novo ◽  
Binding Protein ◽  
Functional Characterization ◽  
Axon Growth ◽  
Motor Deficits ◽  
Neurofilament Light ◽  
Cytoplasmic Inclusions

Neurofilaments (NFs), a major cytoskeletal component of motor neurons, play a key role in the differentiation, establishment and maintenance of their morphology and mechanical strength. The de novo assembly of these neuronal intermediate filaments requires the presence of the neurofilament light subunit (NEFL), whose expression is reduced in motor neurons in amyotrophic lateral sclerosis (ALS). This study used zebrafish as a model to characterize the NEFL homologue neflb, which encodes two different isoforms via a splicing of the primary transcript (neflbE4 and neflbE3). In vivo imaging showed that neflb is crucial for proper neuronal development, and that disrupting the balance between its two isoforms specifically affects the NF assembly and motor axon growth, with resultant motor deficits. This equilibrium is also disrupted upon the partial depletion of TDP-43 (TAR DNA-binding protein 43), an RNA-binding protein encoded by the gene TARDBP that is mislocalized into cytoplasmic inclusions in ALS. The study supports the interaction of the NEFL expression and splicing with TDP-43 in a common pathway, both biologically and pathogenetically.

scholarly journals A motor neuron disease–associated mutation in p150Glued perturbs dynactin function and induces protein aggregation

2006 ◽  
Vol 172 (5) ◽  
pp. 733-745 ◽  
Author(s):  
Jennifer R. Levy ◽  
Charlotte J. Sumner ◽  
Juliane P. Caviston ◽  
Mariko K. Tokito ◽  
Srikanth Ranganathan ◽  
...  
Keyword(s):  
Cell Death ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Mitotic Spindle ◽  
Cytoplasmic Dynein ◽  
Aggregate Formation ◽  
Microtubule Motor ◽  
Delayed Recovery

The microtubule motor cytoplasmic dynein and its activator dynactin drive vesicular transport and mitotic spindle organization. Dynactin is ubiquitously expressed in eukaryotes, but a G59S mutation in the p150Glued subunit of dynactin results in the specific degeneration of motor neurons. This mutation in the conserved cytoskeleton-associated protein, glycine-rich (CAP-Gly) domain lowers the affinity of p150Glued for microtubules and EB1. Cell lines from patients are morphologically normal but show delayed recovery after nocodazole treatment, consistent with a subtle disruption of dynein/dynactin function. The G59S mutation disrupts the folding of the CAP-Gly domain, resulting in aggregation of the p150Glued protein both in vitro and in vivo, which is accompanied by an increase in cell death in a motor neuron cell line. Overexpression of the chaperone Hsp70 inhibits aggregate formation and prevents cell death. These data support a model in which a point mutation in p150Glued causes both loss of dynein/dynactin function and gain of toxic function, which together lead to motor neuron cell death.

scholarly journals Transport and Secretion of the Wnt3 Ligand by Motor Neuron-like Cells and Developing Motor Neurons

Biomolecules ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1898
Author(s):  
Cristina Pinto ◽  
Viviana Pérez ◽  
Jessica Mella ◽  
Miguel Albistur ◽  
Teresa Caprile ◽  
...  
Keyword(s):  
Motor Neuron ◽  
Motor Neurons ◽  
Nerve Terminal ◽  
Motor Nerve ◽  
Motor Nerve Terminal ◽  
In Ovo ◽  
Wnt Ligands ◽  
Postsynaptic Differentiation

The vertebrate neuromuscular junction (NMJ) is formed by a presynaptic motor nerve terminal and a postsynaptic muscle specialization. Cumulative evidence reveals that Wnt ligands secreted by the nerve terminal control crucial steps of NMJ synaptogenesis. For instance, the Wnt3 ligand is expressed by motor neurons at the time of NMJ formation and induces postsynaptic differentiation in recently formed muscle fibers. However, the behavior of presynaptic-derived Wnt ligands at the vertebrate NMJ has not been deeply analyzed. Here, we conducted overexpression experiments to study the expression, distribution, secretion, and function of Wnt3 by transfection of the motor neuron-like NSC-34 cell line and by in ovo electroporation of chick motor neurons. Our findings reveal that Wnt3 is transported along motor axons in vivo following a vesicular-like pattern and reaches the NMJ area. In vitro, we found that endogenous Wnt3 expression increases as the differentiation of NSC-34 cells proceeds. Although NSC-34 cells overexpressing Wnt3 do not modify their morphological differentiation towards a neuronal phenotype, they effectively induce acetylcholine receptor clustering on co-cultured myotubes. These findings support the notion that presynaptic Wnt3 is transported and secreted by motor neurons to induce postsynaptic differentiation in nascent NMJs.

Axonal Growth Abnormalities Underlying Ocular Cranial Nerve Disorders

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Mary C. Whitman
Keyword(s):  
Axon Guidance ◽  
Motor Neurons ◽  
Motor Nerve ◽  
Axon Growth ◽  
Annual Review ◽  
Publication Date ◽  
Causative Gene ◽  
Axon Targeting ◽  
Vision Science ◽  
Motor Nerves

Abnormalities in cranial motor nerve development cause paralytic strabismus syndromes, collectively referred to as congenital cranial dysinnervation disorders, in which patients cannot fully move their eyes. These disorders can arise through one of two mechanisms: ( a) defective motor neuron specification, usually by loss of a transcription factor necessary for brainstem patterning, or ( b) axon growth and guidance abnormalities of the oculomotor, trochlear, and abducens nerves. This review focuses on our current understanding of axon guidance mechanisms in the cranial motor nerves and how disease-causing mutations disrupt axon targeting. Abnormalities of axon growth and guidance are often limited to a single nerve or subdivision, even when the causative gene is ubiquitously expressed. Additionally, when one nerve is absent, its normal target muscles attract other motor neurons. Study of these disorders highlights the complexities of axon guidance and how each population of neurons uses a unique but overlapping set of axon guidance pathways. Expected final online publication date for the Annual Review of Vision Science, Volume 7 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals MP Resulting in Autophagic Cell Death of Microglia through Zinc Changes against Spinal Cord Injury

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Dingding Li ◽  
Guannan Wang ◽  
Donghe Han ◽  
Jing Bi ◽  
Chenyuan Li ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Cell Death ◽  
Motor Neurons ◽  
Neuroprotective Effect ◽  
Pulse Therapy ◽  
Autophagic Cell Death ◽  
Cord Injury

Methylprednisolone pulse therapy (MPPT), as a public recognized therapy of spinal cord injury (SCI), is doubted recently, and the exact mechanism of MP on SCI is unclear. This study sought to investigate the exact effect of MP on SCI. We examined the effect of MP in a model of SCI in vivo and an LPS induced model in vitro. We found that administration of MP produced an increase in the Basso, Beattie, and Bresnahan scores and motor neurons counts of injured rats. Besides the number of activated microglia was apparently reduced by MP in vivo, and Beclin-1 dependent autophagic cell death of microglia was induced by MP in LPS induced model. At the same time, MP increases cellular zinc concentration and level of ZIP8, and TPEN could revert effect of MP on autophagic cell death of microglia. Finally, we have found that MP could inhibit NF-κβin LPS induced model. These results show that the MP could result in autophagic cell death of microglia, which mainly depends on increasing cellular labile zinc, and may be associated with inhibition of NF-κβ, and that MP can produce neuroprotective effect in SCI.

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