scholarly journals The Timing and Extent of Motor Neuron Vulnerability in ALS Correlates with Accumulation of Misfolded SOD1 Protein in the Cortex and in the Spinal Cord

Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 502
Author(s):  
Baris Genc ◽  
Oge Gozutok ◽  
Nuran Kocak ◽  
P. Hande Ozdinler
Keyword(s):  
Spinal Cord ◽  
Drug Discovery ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Selective Vulnerability ◽  
Motor Neuron Diseases ◽  
Neuron Populations ◽  
Misfolded Sod1 ◽  
Over Time

Understanding the cellular and molecular basis of selective vulnerability has been challenging, especially for motor neuron diseases. Developing drugs that improve the health of neurons that display selective vulnerability relies on in vivo cell-based models and quantitative readout measures that translate to patient outcome. We initially developed and characterized UCHL1-eGFP mice, in which motor neurons are labeled with eGFP that is stable and long-lasting. By crossing UCHL1-eGFP to amyotrophic lateral sclerosis (ALS) disease models, we generated ALS mouse models with fluorescently labeled motor neurons. Their examination over time began to reveal the cellular basis of selective vulnerability even within the related motor neuron pools. Accumulation of misfolded SOD1 protein both in the corticospinal and spinal motor neurons over time correlated with the timing and extent of degeneration. This further proved simultaneous degeneration of both upper and lower motor neurons, and the requirement to consider both upper and lower motor neuron populations in drug discovery efforts. Demonstration of the direct correlation between misfolded SOD1 accumulation and motor neuron degeneration in both cortex and spinal cord is important for building cell-based assays in vivo. Our report sets the stage for shifting focus from mice to diseased neurons for drug discovery efforts, especially for motor neuron diseases.

Lower Motor Neuron Disease with Accumulation of Neurofilaments in a Cat

1976 ◽  
Vol 13 (6) ◽  
pp. 428-435 ◽  
Author(s):  
M. Vandevelde ◽  
C. E. Greene ◽  
E. J. Hoff
Keyword(s):  
Spinal Cord ◽  
Motor Neuron ◽  
Motor Neuron Disease ◽  
Histological Examination ◽  
Muscle Atrophy ◽  
Motor Neurons ◽  
Nerve Cells ◽  
Lower Motor Neuron ◽  
Motor Neuron Diseases ◽  
Lower Motor Neuron Disease

A young cat had signs of tetraparesis that progressed to tetraplegia within a few weeks. Clinically, there was lower motor neuron disease with areflexia and muscle atrophy in all limbs. Degeneration of the motor neurons in the spinal cord was seen on histological examination. Ultrastructurally, the degeneration of nerve cells was characterized by abnormal proliferation of neurofilaments. These findings were compared to other motor neuron diseases and neurofibrillary accumulations in man and animals.

scholarly journals “Stretch-Growth” of Motor Axons in Custom Mechanobioreactors to Generate Long-Projecting Axonal and Axonal-Myocyte Constructs

2019 ◽  
Author(s):  
Kritika S. Katiyar ◽  
Laura A. Struzyna ◽  
Suradip Das ◽  
D. Kacy Cullen
Keyword(s):  
Spinal Cord ◽  
Nervous System ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Motor Axon ◽  
Central Feature ◽  
Motor Axons ◽  
Ganglion Neurons

AbstractThe central feature of peripheral motor axons is their remarkable lengths as they project from a motor neuron residing in the spinal cord to an often-distant target muscle. However, to date in vitro models have not replicated this central feature owing to challenges in generating motor axon tracts beyond a few millimeters in length. To address this, we have developed a novel combination of micro-tissue engineering and mechanically assisted growth techniques to create long-projecting centimeter-scale motor axon tracts. Here, primary motor neurons were isolated from the spinal cords of rats and induced to form engineered micro-spheres via forced aggregation in custom micro-wells. This three-dimensional micro-tissue yielded healthy motor neurons projecting dense, fasciculated axonal tracts. Within our custom-built mechanobioreactors, motor neuron culture conditions, neuronal/axonal architecture, and mechanical growth conditions were systematically optimized to generate parameters for robust and efficient “stretch-growth” of motor axons. We found that axons projecting from motor neuron aggregates were able to respond to axon displacement rates at least 10 times greater than that tolerated by axons projecting from dissociated motor neurons. The growth and structural characteristics of these stretch-grown motor axons were compared to benchmark stretch-grown axons from sensory dorsal root ganglion neurons, revealing similar axon densities yet increased motor axon fasciculation. Finally, motor axons were integrated with myocytes and then stretch-grown to create novel long-projecting axonal-myocyte constructs that better recreate characteristic dimensions of native nerve-muscle anatomy. This is the first demonstration of mechanical elongation of spinal cord motor axons and may have applications as anatomically inspired in vitro testbeds or as tissue engineered “living scaffolds” for targeted axon tract reconstruction following nervous system injury or disease.Significance StatementWe have developed novel axon tracts of unprecedented lengths spanning either two discrete populations of neurons or a population of neurons and skeletal myocytes. This is the first demonstration of “stretch-grown” motor axons that recapitulate the structure of spinal motor neurons in vivo by projecting long axons from a pool of motor neurons to distant targets, and may have applications as anatomically inspired in vitro test beds to study mechanisms of axon growth, development, and neuromuscular function in anatomically accurate axo-myo constructs; as well as serve as “living scaffolds” in vivo for targeted axon tract reconstruction following nervous system trauma.

scholarly journals An Inherited Lower Motor Neuron Disease of Pigs: Clinical Signs in Two Litters and Pathology of an Affected Pig

1994 ◽  
Vol 6 (1) ◽  
pp. 62-71 ◽  
Author(s):  
Donal O'Toole ◽  
James Ingram ◽  
Val Welch ◽  
Katie Bardsley ◽  
Tom Haven ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Clinical Signs ◽  
Spinal Nerve ◽  
Neuronal System ◽  
Motor Neuron Diseases ◽  
System Degeneration ◽  
Progressive Neurodegeneration ◽  
Gross Lesions

A chronic progressive neurodegeneration, called hereditary porcine neuronal system degeneration (HPNSD), was recognized in a swine herd in Devon, England. Adult pigs that were presumed carriers of the dominantly inherited trait for HPNSD were transferred from England, where a breeding colony was maintained for 9 years, to the Wyoming State Veterinary Laboratory (WSVL) for study. Two litters of affected piglets were born to 2 carrier sows at the WSVL. Clinical signs of muscular tremors, paresis, or ataxia developed at 12–59 days of age in 4 of 6 liveborn pigs. Three other pigs were stillborn. In the 4 affected livebom pigs, clinical signs progressed and included symmetrical (3 pigs) or asymmetrical (1 pig) posterior paresis, bilateral knuckling of metatarsal-phalangeal or carpal joints, poor exercise tolerance, and in 1 pig, marked hind limb hypermetria. A 34-kg gilt exhibiting clinical signs of muscular tremors and posterior paresis and clinical signs for 22 days was euthanized and examined postmortem at 83 days of age. Apart from decubitus ulcers, gross lesions were absent. Microscopically, perikaryal vacuolation and osmiophilic lipid droplets were observed in atrophic alpha motor neurons in the spinal cord. There was axonal (Wallerian) degeneration in sulcomarginal and dorsal spinocerebellar tracts. Axonal degeneration also involved ventral but not dorsal spinal nerve roots, and was present in eight peripheral nerves sampled for histopathology. Changes in skeletal muscles were consistent with denervation atrophy and were most pronounced in M. tibialis cranialis of the 6 muscles sampled. Immunohistochemical staining of spinal cord for phosphorylated and nonphosphorylated neurofilaments did not reveal abnormal patterns, unlike some well-characterized inherited motor neuron diseases in other species.

scholarly journals AAV2/9-mediated overexpression of MIF inhibits SOD1 misfolding, delays disease onset, and extends survival in mouse models of ALS

2019 ◽  
Vol 116 (29) ◽  
pp. 14755-14760 ◽  
Author(s):  
Marcel F. Leyton-Jaimes ◽  
Joy Kahn ◽  
Adrian Israelson
Keyword(s):  
Spinal Cord ◽  
Motor Neurons ◽  
Therapeutic Potential ◽  
Disease Onset ◽  
Mutant Sod1 ◽  
Protein Levels ◽  
Specific Accumulation ◽  
Intracellular Organelles ◽  
Misfolded Sod1

Mutations in superoxide dismutase (SOD1) cause amyotrophic lateral sclerosis (ALS), a neurodegenerative disease characterized by the loss of upper and lower motor neurons. Transgenic mice that overexpress mutant SOD1 develop paralysis and accumulate misfolded SOD1 onto the cytoplasmic faces of intracellular organelles, including mitochondria and endoplasmic reticulum (ER). Recently, macrophage migration inhibitory factor (MIF) was shown to directly inhibit mutant SOD1 misfolding and binding to intracellular membranes. In addition, complete elimination of endogenous MIF accelerated disease onset and late disease progression, as well as shortened the lifespan of mutant SOD1 mice with higher amounts of misfolded SOD1 detected within the spinal cord. Based on these findings, we used adeno-associated viral (AAV) vectors to overexpress MIF in the spinal cord of mutant SOD1G93A and loxSOD1G37R mice. Our data show that MIF mRNA and protein levels were increased in the spinal cords of AAV2/9-MIF–injected mice. Furthermore, mutant SOD1G93A and loxSOD1G37R mice injected with AAV2/9-MIF demonstrated a significant delay in disease onset and prolonged survival compared with their AAV2/9-GFP–injected or noninjected littermates. Moreover, these mice accumulated reduced amounts of misfolded SOD1 in their spinal cords, with no observed effect on glial overactivation as a result of MIF up-regulation. Our findings indicate that MIF plays a significant role in SOD1 folding and misfolding mechanisms and strengthen the hypothesis that MIF acts as a chaperone for misfolded SOD1 in vivo and may have further implications regarding the therapeutic potential role of up-regulation of MIF in modulating the specific accumulation of misfolded SOD1.

scholarly journals Motor Neuron Diseases and Neuroprotective Peptides: A Closer Look to Neurons

2021 ◽  
Vol 13 ◽  
Author(s):  
Emanuela Zuccaro ◽  
Diana Piol ◽  
Manuela Basso ◽  
Maria Pennuto
Keyword(s):  
Motor Neuron ◽  
Motor Neurons ◽  
Muscular Atrophy ◽  
Selective Vulnerability ◽  
Therapeutic Interventions ◽  
Motor Neuron Diseases ◽  
Somatomedin C ◽  
Beneficial Effects ◽  
Pituitary Adenylate Cyclase ◽  
Lateral Sclerosis

Motor neurons (MNs) are specialized neurons responsible for muscle contraction that specifically degenerate in motor neuron diseases (MNDs), such as amyotrophic lateral sclerosis (ALS), spinal and bulbar muscular atrophy (SBMA), and spinal muscular atrophy (SMA). Distinct classes of MNs degenerate at different rates in disease, with a particular class named fast-fatigable MNs (FF-MNs) degenerating first. The etiology behind the selective vulnerability of FF-MNs is still largely under investigation. Among the different strategies to target MNs, the administration of protective neuropeptides is one of the potential therapeutic interventions. Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide with beneficial effects in many neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, and more recently SBMA. Another neuropeptide that has a neurotrophic effect on MNs is insulin-like growth factor 1 (IGF-1), also known as somatomedin C. These two peptides are implicated in the activation of neuroprotective pathways exploitable in the amelioration of pathological outcomes related to MNDs.

scholarly journals LanCL1 promotes motor neuron survival and extends the lifespan of amyotrophic lateral sclerosis mice

2019 ◽  
Vol 27 (4) ◽  
pp. 1369-1382 ◽  
Author(s):  
Honglin Tan ◽  
Mina Chen ◽  
Dejiang Pang ◽  
Xiaoqiang Xia ◽  
Chongyangzi Du ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Neuronal Survival ◽  
Disease Onset ◽  
Alternative Mechanism ◽  
Specific Expression ◽  
Motor Neuron Survival ◽  
Lateral Sclerosis

Abstract Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive loss of motor neurons. Improving neuronal survival in ALS remains a significant challenge. Previously, we identified Lanthionine synthetase C-like protein 1 (LanCL1) as a neuronal antioxidant defense gene, the genetic deletion of which causes apoptotic neurodegeneration in the brain. Here, we report in vivo data using the transgenic SOD1G93A mouse model of ALS indicating that CNS-specific expression of LanCL1 transgene extends lifespan, delays disease onset, decelerates symptomatic progression, and improves motor performance of SOD1G93A mice. Conversely, CNS-specific deletion of LanCL1 leads to neurodegenerative phenotypes, including motor neuron loss, neuroinflammation, and oxidative damage. Analysis reveals that LanCL1 is a positive regulator of AKT activity, and LanCL1 overexpression restores the impaired AKT activity in ALS model mice. These findings indicate that LanCL1 regulates neuronal survival through an alternative mechanism, and suggest a new therapeutic target in ALS.

scholarly journals Targeted axonal import (TAxI) peptide delivers functional proteins into spinal cord motor neurons after peripheral administration

2016 ◽  
Vol 113 (9) ◽  
pp. 2514-2519 ◽  
Author(s):  
Drew L. Sellers ◽  
Jamie M. Bergen ◽  
Russell N. Johnson ◽  
Heidi Back ◽  
John M. Ravits ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Motor Neurons ◽  
Unmet Need ◽  
Nerve Roots ◽  
Biologic Drugs ◽  
Administration Routes ◽  
Macromolecular Drugs ◽  
The Central Nervous System ◽  
Clinical Potential

A significant unmet need in treating neurodegenerative disease is effective methods for delivery of biologic drugs, such as peptides, proteins, or nucleic acids into the central nervous system (CNS). To date, there are no operative technologies for the delivery of macromolecular drugs to the CNS via peripheral administration routes. Using an in vivo phage-display screen, we identify a peptide, targeted axonal import (TAxI), that enriched recombinant bacteriophage accumulation and delivered protein cargo into spinal cord motor neurons after intramuscular injection. In animals with transected peripheral nerve roots, TAxI delivery into motor neurons after peripheral administration was inhibited, suggesting a retrograde axonal transport mechanism for delivery into the CNS. Notably, TAxI-Cre recombinase fusion proteins induced selective recombination and tdTomato-reporter expression in motor neurons after intramuscular injections. Furthermore, TAxI peptide was shown to label motor neurons in the human tissue. The demonstration of a nonviral-mediated delivery of functional proteins into the spinal cord establishes the clinical potential of this technology for minimally invasive administration of CNS-targeted therapeutics.

Motor Neuron Diseases

2014 ◽  
Author(s):  
Elena Ratti ◽  
Merit E. Cudkowicz ◽  
James D Berry
Keyword(s):  
Motor Neuron ◽  
Motor Neurons ◽  
Viral Infections ◽  
Inflammatory Responses ◽  
Muscular Atrophy ◽  
Experimental Therapy ◽  
Rapid Progression ◽  
Motor Neuron Diseases ◽  
Efficacy Outcome ◽  
Single Disease Entity

The motor neuron diseases (MNDs) are a family of diseases commonly categorized by their propensity to affect upper or lower motor neurons and by their mode of inheritance. The chapter provides some content on infectious MNDs caused by viral infections affecting the motor neurons in the anterior horn of the spinal cord. However, the chapter devotes most of its attention to the inherited and sporadically occurring MNDs. The majority of research into adult MND focuses on amyotrophic lateral sclerosis (ALS) due to its high prevalence, rapid progression, and phenotypical similarities between its inherited form and its sporadic form. As our knowledge of genetic mechanisms underlying ALS pathology has grown, common themes have emerged. These include abnormalities in RNA biology, axonal transport, protein folding, and inflammatory responses. These themes currently drive much of the direction in ALS experimental therapy development. It is clear that MND is complex and involves several different molecular pathways. Given this complexity, ALS might not be a single disease entity, and if this is the case, treatment approaches may need to be targeted to specific pathologies rather than all ALS patients on a broad scale. Chapter content is enhanced by tables outlining the types of MNDs, criteria for supporting a diagnosis, first-line workup, the genes associated with ALS, ALS efficacy outcome measures, symptom management of ALS, and spinal muscular atrophy classification. Mechanisms of ALS are illustrated, and clinical photographs demonstrate symptoms. This chapter contains 252 references. 

The control of rostrocaudal pattern in the developing spinal cord: specification of motor neuron subtype identity is initiated by signals from paraxial mesoderm

Development ◽  
1998 ◽  
Vol 125 (6) ◽  
pp. 969-982 ◽  
Author(s):  
M. Ensini ◽  
T.N. Tsuchida ◽  
H.G. Belting ◽  
T.M. Jessell
Keyword(s):  
Spinal Cord ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Neural Tube ◽  
Motor Behavior ◽  
Neural Tube Closure ◽  
Paraxial Mesoderm ◽  
Homeodomain Protein ◽  
Mesodermal Cell ◽  
Developing Spinal Cord

The generation of distinct classes of motor neurons is an early step in the control of vertebrate motor behavior. To study the interactions that control the generation of motor neuron subclasses in the developing avian spinal cord we performed in vivo grafting studies in which either the neural tube or flanking mesoderm were displaced between thoracic and brachial levels. The positional identity of neural tube cells and motor neuron subtype identity was assessed by Hox and LIM homeodomain protein expression. Our results show that the rostrocaudal identity of neural cells is plastic at the time of neural tube closure and is sensitive to positionally restricted signals from the paraxial mesoderm. Such paraxial mesodermal signals appear to control the rostrocaudal identity of neural tube cells and the columnar subtype identity of motor neurons. These results suggest that the generation of motor neuron subtypes in the developing spinal cord involves the integration of distinct rostrocaudal and dorsoventral patterning signals that derive, respectively, from paraxial and axial mesodermal cell groups.

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