Long-Term Suppression of c-Jun and nNOS Preserves Ultrastructural Features of Lower Motor Neurons and Forelimb Function after Brachial Plexus Roots Avulsion

Brachial plexus root avulsions cause debilitating upper limb paralysis. Short-term neuroprotective treatments have reported preservation of motor neurons and function in model animals while reports of long-term benefits of such treatments are scarce, especially the morphological sequelae. This morphological study investigated the long-term suppression of c-Jun- and neuronal nitric oxide synthase (nNOS) (neuroprotective treatments for one month) on the motor neuron survival, ultrastructural features of lower motor neurons, and forelimb function at six months after brachial plexus roots avulsion. Neuroprotective treatments reduced oxidative stress and preserved ventral horn motor neurons at the end of the 28-day treatment period relative to vehicle treated ones. Motor neuron sparing was associated with suppression of c-Jun, nNOS, and pro-apoptotic proteins Bim and caspases at this time point. Following 6 months of survival, neutral red staining revealed a significant loss of most of the motor neurons and ventral horn atrophy in the avulsed C6, 7, and 8 cervical segments among the vehicle-treated rats (n = 4). However, rats that received neuroprotective treatments c-Jun JNK inhibitor, SP600125 (n = 4) and a selective inhibitor of nNOS, 7-nitroindazole (n = 4), retained over half of their motor neurons in the ipsilateral avulsed side compared. Myelinated axons in the avulsed ventral horns of vehicle-treated rats were smaller but numerous compared to the intact contralateral ventral horns or neuroprotective-treated groups. In the neuroprotective treatment groups, there was the preservation of myelin thickness around large-caliber axons. Ultrastructural evaluation also confirmed the preservation of organelles including mitochondria and synapses in the two groups that received neuroprotective treatments compared with vehicle controls. Also, forelimb functional evaluation demonstrated that neuroprotective treatments improved functional abilities in the rats. In conclusion, neuroprotective treatments aimed at suppressing degenerative c-Jun and nNOS attenuated apoptosis, provided long-term preservation of motor neurons, their organelles, ventral horn size, and forelimb function.

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A Monolayer System for the Efficient Generation of Motor Neuron Progenitors and Functional Motor Neurons from Human Pluripotent Stem Cells

Cells ◽

10.3390/cells10051127 ◽

2021 ◽

Vol 10 (5) ◽

pp. 1127

Author(s):

Alessandro Cutarelli ◽

Vladimir A. Martínez-Rojas ◽

Alice Tata ◽

Ingrid Battistella ◽

Daniela Rossi ◽

...

Keyword(s):

Stem Cells ◽

Motor Neuron ◽

Motor Neurons ◽

Pluripotent Stem Cells ◽

Disease Modelling ◽

Disease Phenotypes ◽

In Vitro Systems ◽

Induced Pluripotent

Methods for the conversion of human induced pluripotent stem cells (hiPSCs) into motor neurons (MNs) have opened to the generation of patient-derived in vitro systems that can be exploited for MN disease modelling. However, the lack of simplified and consistent protocols and the fact that hiPSC-derived MNs are often functionally immature yet limit the opportunity to fully take advantage of this technology, especially in research aimed at revealing the disease phenotypes that are manifested in functionally mature cells. In this study, we present a robust, optimized monolayer procedure to rapidly convert hiPSCs into enriched populations of motor neuron progenitor cells (MNPCs) that can be further amplified to produce a large number of cells to cover many experimental needs. These MNPCs can be efficiently differentiated towards mature MNs exhibiting functional electrical and pharmacological neuronal properties. Finally, we report that MN cultures can be long-term maintained, thus offering the opportunity to study degenerative phenomena associated with pathologies involving MNs and their functional, networked activity. These results indicate that our optimized procedure enables the efficient and robust generation of large quantities of MNPCs and functional MNs, providing a valid tool for MNs disease modelling and for drug discovery applications.

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Neonatal Death in Mice Lacking Cardiotrophin-like Cytokine is Associated with Multifocal Neuronal Hypoplasia

Veterinary Pathology ◽

10.1354/vp.08-vp-0239-b-bc ◽

2008 ◽

Vol 46 (3) ◽

pp. 514-519 ◽

Cited By ~ 18

Author(s):

X. Zou ◽

B. Bolon ◽

J. K. Pretorius ◽

C. Kurahara ◽

J. McCabe ◽

...

Keyword(s):

Motor Neuron ◽

Motor Neurons ◽

Ventral Horn ◽

Lumbar Spinal Cord ◽

Facial Nucleus ◽

In Ovo ◽

Neuron Survival ◽

Motor Neuron Survival ◽

Lumbar Spinal

Mice with null mutations of ciliary neurotrophic factor (Cntf) receptor alpha (Cntf-Rα), or cytokine-like factor 1 (Clf), one component of Cntf-II (a heterodimeric Cntf-Rα ligand), die as neonates from motor neuron loss affecting the facial nucleus and ventral horn of the lumbar spinal cord. Exposure to cardiotrophin-like cytokine (Clc), the other putative Cntf-II element, supports motor neuron survival in vitro and in ovo. Confirmation that Clc ablation induces an equivalent phenotype to Clf deletion would support a role for Clc in the functional Cntf-II complex. In this study, Clc knockout mice had decreased facial motility, did not suckle, died within 24 hours, and had 32% and 29% fewer motor neurons in the facial nucleus and lumbar ventral horn, respectively; thus, Clc is essential for motor neuron survival during development. The concordance of the Clc knockout phenotype with those of mice lacking Cntf-Rα or Clf bolsters the hypothesis that Clc participates in Cntf-II.

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Muscle and epidermal contributions of the structural protein β-spectrin promote hypergravity-induced motor neuron axon defects in C. elegans

Scientific Reports ◽

10.1038/s41598-020-78414-y ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Saraswathi S. Kalichamy ◽

Alfredo V. Alcantara ◽

Ban-Seok Kim ◽

Junsoo Park ◽

Kyoung-hye Yoon ◽

...

Keyword(s):

Extracellular Matrix ◽

Motor Neuron ◽

Motor Neurons ◽

High Gravity ◽

Axon Pathfinding ◽

Structural Protein ◽

Long Term Effects ◽

C Elegans ◽

Migration Pathways

AbstractBiology is adapted to Earth’s gravity force, and the long-term effects of varying gravity on the development of animals is unclear. Previously, we reported that high gravity, called hypergravity, increases defects in the development of motor neuron axons in the nematode Caenorhabditis elegans. Here, we show that a mutation in the unc-70 gene that encodes the cytoskeletal β-spectrin protein suppresses hypergravity-induced axon defects. UNC-70 expression is required in both muscle and epidermis to promote the axon defects in high gravity. We reveal that the location of axon defects is correlated to the size of the muscle cell that the axon traverses. We also show that mutations that compromise key proteins of hemidesmosomal structures suppress hypergravity-induced axon defects. These hemidesmosomal structures play a crucial role in coupling mechanical force between the muscle, epidermis and the external cuticle. We speculate a model in which the rigid organization of muscle, epidermal and cuticular layers under high gravity pressure compresses the narrow axon migration pathways in the extracellular matrix hindering proper axon pathfinding of motor neurons.

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Identification of 17 highly expressed genes within mouse lumbar spinal cord anterior horn region from an in-situ hybridization atlas of 3430 genes: implications for motor neuron disease

Neurology International ◽

10.4081/ni.2014.5367 ◽

2014 ◽

Vol 6 (2) ◽

Cited By ~ 8

Author(s):

Michael A. Meyer

Keyword(s):

Spinal Cord ◽

Motor Neuron ◽

Motor Neuron Disease ◽

Motor Neurons ◽

Ventral Horn ◽

Janus Kinase ◽

Anterior Horn ◽

Lumbar Spinal Cord ◽

Spinal Motor ◽

Lumbar Spinal

In an effort to find possible new gene candidates involved in the causation of amyotrophic lateral sclerosis (ALS), a prior version of the on-line brain gene expression atlas GENSAT was extensively searched for selectively intense expression within spinal motor neurons. Using autoradiographic data of in-situ hybridization from 3430 genes, a search for selectively intense activity was made for the anterior horn region of murine lumbar spinal cord sectioned in the axial plane. Of 3430 genes, a group of 17 genes was found to be highly expressed within the anterior horn suggesting localization to its primary cellular constituent, the alpha spinal motor neuron. For some genes, an inter-relationship to ALS was already known, such as for heavy, medium, and light neurofilaments, and peripherin. Other genes identified include: Gamma Synuclein, GDNF, SEMA3A, Extended Synaptotagmin-like protein 1, LYNX1, HSPA12a, Cadherin 22, PRKACA, TPPP3 as well as Choline Acetyltransferase, Janus Kinase 1, and the Motor Neuron and Pancreas Homeobox 1. Based on this study, Fibroblast Growth Factor 1 was found to have a particularly selective and intense localization pattern to the ventral horn and may be a good target for development of motor neuron disease therapies; further research is needed.

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Isolation of Mature Spinal Motor Neurons and Single-cell Analysis Using the Comet Assay of Early Low-level DNA Damage Induced In Vitro and In Vivo

Journal of Histochemistry & Cytochemistry ◽

10.1177/002215540104900804 ◽

2001 ◽

Vol 49 (8) ◽

pp. 957-972 ◽

Cited By ~ 12

Author(s):

Zhiping Liu ◽

Lee J. Martin

Keyword(s):

Dna Damage ◽

Comet Assay ◽

Motor Neuron ◽

Single Cell ◽

Motor Neurons ◽

Ventral Horn ◽

Motor Neuron Degeneration ◽

Spinal Motor Neurons

We developed an isolation technique for motor neurons from adult rat spinal cord. Spinal cord enlargements were discretely microdissected into ventral horn tissue columns that were trypsin-digested and subjected to differential low-speed centrifugation to fractionate ventral horn cell types. A fraction enriched in α-motor neurons was isolated. Motor neuron enrichment was verified by immunofluorescence for choline acetyltransferase and prelabeling axon projections to skeletal muscle. Adult motor neurons were isolated from naïve rats and were exposed to oxidative agents or were isolated from rats with sciatic nerve lesions (avulsions). We tested the hypothesis, using single-cell gel electrophoresis (comet assay), that hydrogen peroxide, nitric oxide, and peroxynitrite exposure in vitro and axotomy in vivo induce DNA damage in adult motor neurons early during their degeneration. This study contributes three important developments in the study of motor neurons. It demonstrates that mature spinal motor neurons can be isolated and used for in vitro models of motor neuron degeneration. It shows that adult motor neurons can be isolated from in vivo models of motor neuron degeneration and evaluated on a single-cell basis. This study also demonstrates that the comet assay is a feasible method for measuring DNA damage in individual motor neurons. Using these methods, we conclude that motor neurons undergoing oxidative stress from reactive oxygen species and axotomy accumulate DNA damage early in their degeneration. (J Histochem Cytochem 49:957–972, 2001)

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Three-Dimensional Mapping of Retrograde Multi-Labeled Motor Neuron Columns in the Spinal Cord

Photonics ◽

10.3390/photonics8050145 ◽

2021 ◽

Vol 8 (5) ◽

pp. 145

Author(s):

Jianyi Xu ◽

Xiaofeng Yin ◽

Yisong Qi ◽

Bo Chen ◽

Yusha Li ◽

...

Keyword(s):

Spinal Cord ◽

Peripheral Nerve ◽

Motor Neuron ◽

Brachial Plexus ◽

Motor Neurons ◽

3D Visualization ◽

Three Dimensional ◽

Optical Clearing ◽

Retrograde Labeling ◽

Functional Relationships

The quantification and distribution characteristics of spinal motor neurons play important roles in the study of spinal cord and peripheral nerve injury and repair. In most research, the sole retrograde labeling of each nerve or muscle could not simultaneously obtain the distributions of different motor neuron subpopulations. Therefore, it did not allow mapping of spatial relationships of different motor neuron columns for disclosing the functional relationship of different nerve branches. Here, we combined the multiple retrograde labeling, optical clearing, and imaging for three-dimensional (3D) visualization of motor neurons of multiple brachial plexus branches. After screening fluorescent tracers by the labeling feasibility of motor neurons and fluorescence compatibility with optical clearing, we performed mapping and quantification of the motor neurons of ulnar, median, and radial nerves in the spinal cord, then disclosed the relative spatial distribution among different neuronal subpopulations. This work will provide valuable mapping data for the understanding of the functional relationships among brachial plexus branches, hopefully facilitating the study of regeneration of axons and remodeling of motor neurons in peripheral nerve repair.

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Reports From the Field: “Vini Ansanm” Come Together for Inclusive Community Music Development in Port-au-Prince, Haiti

The Oxford Handbook of Social Media and Music Learning ◽

10.1093/oxfordhb/9780190660772.013.17 ◽

2020 ◽

pp. 273-289

Author(s):

Donald DeVito ◽

Gertrude Bien-Aime ◽

Hannah Ehrli ◽

Jamie Schumacher

Keyword(s):

Social Media ◽

Inclusive Education ◽

Children With Disabilities ◽

Small Population ◽

Significant Loss ◽

Community Music ◽

Music Learning ◽

Loss Of Life

Haiti has experienced a series of catastrophic natural disasters in recent decades, resulting in significant loss of life and long-term damage to infrastructure. One critical outcome of these disasters is that there are approximately 400,000 orphans in the small population of just over 10 million. Throughout Haiti, children with disabilities are often considered cursed, and thus are rejected by the community in which they live. Haitian children with disabilities need creative and educational activities that will help them grow, develop, enjoy their lives, and become accepted members of the community. This chapter on the Haitian Center for Inclusive Education presents a case study of social media engagement and music learning, with an emphasis on social justice that has contributed to sustainable efforts.

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Global transcriptome profile of the developmental principles of in vitro iPSC-to-motor neuron differentiation

BMC Molecular and Cell Biology ◽

10.1186/s12860-021-00343-z ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Emilia Solomon ◽

Katie Davis-Anderson ◽

Blake Hovde ◽

Sofiya Micheva-Viteva ◽

Jennifer Foster Harris ◽

...

Keyword(s):

Stem Cells ◽

Neural Stem Cells ◽

Motor Neuron ◽

Motor Neurons ◽

Acetylcholine Receptors ◽

Gene Networks ◽

Spinal Cord Injuries ◽

Regulatory Gene ◽

Transcriptome Profile

Abstract Background Human induced pluripotent stem cells (iPSC) have opened new avenues for regenerative medicine. Consequently, iPSC-derived motor neurons have emerged as potentially viable therapies for spinal cord injuries and neurodegenerative disorders including Amyotrophic Lateral Sclerosis. However, direct clinical application of iPSC bears in itself the risk of tumorigenesis and other unforeseeable genetic or epigenetic abnormalities. Results Employing RNA-seq technology, we identified and characterized gene regulatory networks triggered by in vitro chemical reprogramming of iPSC into cells with the molecular features of motor neurons (MNs) whose function in vivo is to innervate effector organs. We present meta-transcriptome signatures of 5 cell types: iPSCs, neural stem cells, motor neuron progenitors, early motor neurons, and mature motor neurons. In strict response to the chemical stimuli, along the MN differentiation axis we observed temporal downregulation of tumor growth factor-β signaling pathway and consistent activation of sonic hedgehog, Wnt/β-catenin, and Notch signaling. Together with gene networks defining neuronal differentiation (neurogenin 2, microtubule-associated protein 2, Pax6, and neuropilin-1), we observed steady accumulation of motor neuron-specific regulatory genes, including Islet-1 and homeobox protein HB9. Interestingly, transcriptome profiling of the differentiation process showed that Ca2+ signaling through cAMP and LPC was downregulated during the conversion of the iPSC to neural stem cells and key regulatory gene activity of the pathway remained inhibited until later stages of motor neuron formation. Pathways shaping the neuronal development and function were well-represented in the early motor neuron cells including, neuroactive ligand-receptor interactions, axon guidance, and the cholinergic synapse formation. A notable hallmark of our in vitro motor neuron maturation in monoculture was the activation of genes encoding G-coupled muscarinic acetylcholine receptors and downregulation of the ionotropic nicotinic acetylcholine receptors expression. We observed the formation of functional neuronal networks as spontaneous oscillations in the extracellular action potentials recorded on multi-electrode array chip after 20 days of differentiation. Conclusions Detailed transcriptome profile of each developmental step from iPSC to motor neuron driven by chemical induction provides the guidelines to novel therapeutic approaches in the re-construction efforts of muscle innervation.

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Lipidomics study of plasma from patients suggest that ALS and PLS are part of a continuum of motor neuron disorders

Scientific Reports ◽

10.1038/s41598-021-92112-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Estela Area-Gomez ◽

D. Larrea ◽

T. Yun ◽

Y. Xu ◽

J. Hupf ◽

...

Keyword(s):

Motor Neuron ◽

Motor Neurons ◽

Cell Structure ◽

Disease Onset ◽

Point Of View ◽

Motor Dysfunction ◽

Cellular Processes ◽

Progressive Muscle Weakness ◽

Human Pathology ◽

Lateral Sclerosis

AbstractMotor neuron disorders (MND) include a group of pathologies that affect upper and/or lower motor neurons. Among them, amyotrophic lateral sclerosis (ALS) is characterized by progressive muscle weakness, with fatal outcomes only in a few years after diagnosis. On the other hand, primary lateral sclerosis (PLS), a more benign form of MND that only affects upper motor neurons, results in life-long progressive motor dysfunction. Although the outcomes are quite different, ALS and PLS present with similar symptoms at disease onset, to the degree that both disorders could be considered part of a continuum. These similarities and the lack of reliable biomarkers often result in delays in accurate diagnosis and/or treatment. In the nervous system, lipids exert a wide variety of functions, including roles in cell structure, synaptic transmission, and multiple metabolic processes. Thus, the study of the absolute and relative concentrations of a subset of lipids in human pathology can shed light into these cellular processes and unravel alterations in one or more pathways. In here, we report the lipid composition of longitudinal plasma samples from ALS and PLS patients initially, and after 2 years following enrollment in a clinical study. Our analysis revealed common aspects of these pathologies suggesting that, from the lipidomics point of view, PLS and ALS behave as part of a continuum of motor neuron disorders.

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Poor Corticospinal Motor Neuron Health Is Associated with Increased Symptom Severity in the Acute Phase Following Repetitive Mild TBI and Predicts Early ALS Onset in Genetically Predisposed Rodents

Brain Sciences ◽

10.3390/brainsci11020160 ◽

2021 ◽

Vol 11 (2) ◽

pp. 160

Author(s):

Mor R. Alkaslasi ◽

Noell E. Cho ◽

Navpreet K. Dhillon ◽

Oksana Shelest ◽

Patricia S. Haro-Lopez ◽

...

Keyword(s):

Risk Factor ◽

Motor Neuron ◽

Motor Neurons ◽

Disease Onset ◽

Poor Health ◽

Disease Symptoms ◽

Established Risk Factor ◽

Early Injury ◽

Corticospinal Motor Neurons ◽

Lateral Sclerosis

Traumatic brain injury (TBI) is a well-established risk factor for several neurodegenerative disorders including Alzheimer’s disease and Parkinson’s disease, however, a link between TBI and amyotrophic lateral sclerosis (ALS) has not been clearly elucidated. Using the SOD1G93A rat model known to recapitulate the human ALS condition, we found that exposure to mild, repetitive TBI lead ALS rats to experience earlier disease onset and shortened survival relative to their sham counterparts. Importantly, increased severity of early injury symptoms prior to the onset of ALS disease symptoms was linked to poor health of corticospinal motor neurons and predicted worsened outcome later in life. Whereas ALS rats with only mild behavioral injury deficits exhibited no observable changes in corticospinal motor neuron health and did not present with early onset or shortened survival, those with more severe injury-related deficits exhibited alterations in corticospinal motor neuron health and presented with significantly earlier onset and shortened lifespan. While these studies do not imply that TBI causes ALS, we provide experimental evidence that head injury is a risk factor for earlier disease onset in a genetically predisposed ALS population and is associated with poor health of corticospinal motor neurons.

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