Protective effect of sodium valproate on motor neurons in the spinal cord following sciatic nerve injury in rats

BACKGROUND: Sodium valproate (VPA) is used to be an effective anti-epileptic drug. VPA possesses the characteristics of penetrating rapidly through the blood-brain barrier (BBB) and increasing levels of Bcl-2 and growth cone-associated protein (GAP) 43 in spinal cord. OBJECTIVE: To observe the effect of VPA on Bcl-2 expression and motor neuronal apoptosis in spinal cord of rats following sciatic nerve transection. DESIGN: Randomized controlled experiment. SETTING: Department of Hand Surgery and Microsurgery, Wuhan Puai Hospital. MATERIALS: A total of 30 male healthy SD rats of clean grade and with the body mass of 180-220 g were provided by Experimental Animal Center of Medical College of Wuhan University. Sodium Valproate Tablets were purchases from Hengrui Pharmaceutical Factory, Jiangsu. METHODS: The experiment was performed in the Central Laboratory of Wuhan Puai Hospital and Medical College of Wuhan University from February to May 2006. Totally 30 rats were randomly divided into two groups: treatment group (n =15) and model group (n =15). Longitudinal incision along backside of right hind limbs of rats was made to expose sciatic nerves, which were sharply transected 1 cm distal to the inferior margin of piriform muscle after nerve liberation under operation microscope to establish sciatic nerve injury rat models. Sodium Valproate Tablets were pulverized and diluted into 50 g/L suspension with saline. On the day of operation, the rats in the treatment group received 6 mL/kg VPA suspension by gastric perfusion, once a day, whereas model group received 10 mL/kg saline by gastric perfusion, once a day. L4-6 spinal cords were obtained at days 1, 4, 7, 14 and 28 after operation, respectively. Terminal deoxyribonucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) technique and immunohistochemical method (SP method) were used to detect absorbance (A) of neurons with positive Bcl-2 expression. Apoptotic rate of cells (number of apoptotic cells/total number of cells×100%) was calculated. MAIN OUTCOME MEASURES: A value of neurons with positive Bcl-2 expression and apoptotic rate in spinal cord of rats in the two groups. RESULTS: A total of 30 SD rats were involved in the result analysis. ①expression of positive Bcl-2 neurons: A value of positive Bcl-2 neurons were 0.71±0.02, 0.86±0.04, 1.02±0.06 at days 4, 7 and 14, respectively after operation in the treatment group, which were obviously higher than those in the model group (0.62±0.03, 0.71±0.05, 0.89±0.04, t = 3.10-4.50, P < 0.05). ②apoptotic result of motor neurons: Apoptotic rate of motor neurons in spinal cord was (6.91±0.89)% and (15.12±2.34)% at days 7 and 14 in the treatment group, which was significantly lower than those in the model group [(9.45±1.61)%, (19.35±0.92)%, t = 2.39, 3.03. P < 0.05]. CONCLUSION: VPA can increase expression of Bcl-2 in spinal cord and reduce neuronal apoptosis in rats following sciatic nerve injury, and has protective effect on motor neuron in spinal cord of rats.

GDNF to the rescue:GDNF delivery effects on motor neurons and nerves,and muscle re-innervation after peripheral nerve injuries

Peripheral nerve injuries commonly occur due to trauma,like a traffic accident.Peripheral nerves get severed,causing motor neuron death and potential muscle atrophy.The current golden standard to treat peripheral nerve lesions,especially lesions with large(≥3 cm)nerve gaps,is the use of a nerve autograft or reimplantation in cases where nerve root avulsions occur.If not tended early,degeneration of motor neurons and loss of axon regeneration can occur,leading to loss of function.Although surgical procedures exist,patients often do not fully recover,and quality of life deteriorates.Peripheral nerves have limited regeneration,and it is usually mediated by Schwann cells and neurotrophic factors,like glial cell line-derived neurotrophic factor,as seen in Wallerian degeneration.Glial cell line-derived neurotrophic factor is a neurotrophic factor known to promote motor neuron survival and neurite outgrowth.Glial cell line-derived neurotrophic factor is upregulated in different forms of nerve injuries like axotomy,sciatic nerve crush,and compression,thus creating great interest to explore this protein as a potential treatment for peripheral nerve injuries.Exogenous glial cell line-derived neurotrophic factor has shown positive effects in regeneration and functional recovery when applied in experimental models of peripheral nerve injuries.In this review,we discuss the mechanism of repair provided by Schwann cells and upregulation of glial cell line-derived neurotrophic factor,the latest findings on the effects of glial cell line-derived neurotrophic factor in different types of peripheral nerve injuries,delivery systems,and complementary treatments(electrical muscle stimulation and exercise).Understanding and overcoming the challenges of proper timing and glial cell line-derived neurotrophic factor delivery is paramount to creating novel treatments to tend to peripheral nerve injuries to improve patients'quality of life.

Effects of targeted muscle reinnervation on spinal cord motor neurons in rats following tibial nerve transection

Targeted muscle reinnervation(TMR)is a surgical procedure used to transfer residual peripheral nerves from amputated limbs to targeted muscles,which allows the target muscles to become sources of motor control information for function reconstruction.However,the effect of TMR on injured motor neurons is still unclear.In this study,we aimed to explore the effect of hind limb TMR surgery on injured motor neurons in the spinal cord of rats after tibial nerve transection.We found that the reduction in hind limb motor function and atrophy in mice caused by tibial nerve transection improved after TMR.TMR enhanced nerve regeneration by increasing the number of axons and myelin sheath thickness in the tibial nerve,increasing the number of anterior horn motor neurons,and increasing the number of choline acetyltransferase-positive cells and immunofluorescence intensity of synaptophysin in rat spinal cord.Our findings suggest that TMR may enable the reconnection of residual nerve fibers to target muscles,thus restoring hind limb motor function on the injured side.

Therapeutic opportunities and challenges of induced pluripotent stem cells-derived motor neurons for treatment of amyotrophic lateral sclerosis and motor neuron disease

Amyotrophic lateral sclerosis(ALS) and motor neuron diseases(MNDs) are progressive neurodegenerative diseases that affect nerve cells in the brain affecting upper and lower motor neurons(UMNs/LMNs), brain stem and spinal cord. The clinical phenotype is characterized by loss of motor neurons(MNs), muscular weakness and atrophy eventually leading to paralysis and death due to respiratory failure within 3–5 years after disease onset. No effective treatment or cure is currently available that halts or reverses ALS and MND except FDA approved drug riluzole that only modestly slows the progression of ALS in some patients. Recent advances in human derived induced pluripotent stem cells have made it possible for the first time to obtain substantial amounts of human cells to recapitulate in vitro "disease in dish" and test some of the underlying pathogenetic mechanisms involved in ALS and MNDs. In this review, I discussed the opportunities and challenges of induced pluropotent stem cells-derived motor neurons for treatment of ALS and MND patients with special emphasis on their implications in finding a cure for ALS and MNDs.

A tale of motor neurons and CD4＋ T cells： moving forward by looking back

Amyotrophic lateral sclerosis(ALS) is a fatal progressive disorder characterized by the selective degeneration of motor neurons(MN). The impact of peripheral immune status on disease progression and MN survival is becoming increasingly recognized in the ALS research field. In this review, we briefly discuss findings from mouse models of peripheral nerve injury and immunodeficiency to understand how the immune system regulates MN survival. We extend these observations to similar studies in the widely used superoxide dismutase 1(SOD1) mouse model of ALS. Last, we present future hypotheses to identify potential causative factors that lead to immune dysregulation in ALS. The lessons from preceding work in this area offer new exciting directions to bridge the gap in our current understanding of immune-mediated neuroprotection in ALS.

SYNGR4 and PLEKHB1 deregulation in motor neurons of amyotrophic lateral sclerosis models: potential contributions to pathobiology

Amyotrophic lateral sclerosis is the most common adult-onset neurodegenerative disease affecting motor neurons. Its defining feature is progressive loss of motor neuron function in the cortex, brainstem, and spinal cord, leading to paralysis and death. Despite major advances in identifying genes that can cause disease when mutated and model the disease in animals and cellular models, it still remains unclear why motor symptoms suddenly appear after a long pre-symptomatic phase of apparently normal function. One hypothesis is that age-related deregulation of specific proteins within key cell types, especially motor neurons themselves, initiates disease symptom appearance and may also drive progressive degeneration. Genome-wide in vivo cell-type-specific screening tools are enabling identification of candidates for such proteins. In this minireview, we first briefly discuss the methodology used in a recent study that applied a motor neuron-specific RNASeq screening approach to a standard model of TAR DNA-binding protein-43(TDP-43)-driven amyotrophic lateral sclerosis. A key finding of this study is that synaptogyrin-4 and pleckstrin homology domain-containing family B member 1 are also deregulated at the protein level within motor neurons of two unrelated mouse models of mutant TDP-43 driven amyotrophic lateral sclerosis. Guided by what is known about molecular and cellular functions of these proteins and their orthologs, we outline here specific hypotheses for how changes in their levels might potentially alter cellular physiology of motor neurons and detrimentally affect motor neuron function. Where possible, we also discuss how this information could potentially be used in a translational context to develop new therapeutic strategies for this currently incurable, devastating disease.

Chx10+V2a interneurons in spinal motor regulation and spinal cord injury

Chx10-expressing V2 a(Chx10+V2 a) spinal interneurons play a large role in the excitatory drive of motoneurons. Chemogenetic ablation studies have demonstrated the essential nature of Chx10+V2 a interneurons in the regulation of locomotor initiation, maintenance, alternation, speed, and rhythmicity. The role of Chx10+V2 a interneurons in locomotion and autonomic nervous system regulation is thought to be robust, but their precise role in spinal motor regulation and spinal cord injury have not been fully explored. The present paper reviews the origin, characteristics, and functional roles of Chx10+V2 a interneurons with an emphasis on their involvement in the pathogenesis of spinal cord injury. The diverse functional properties of these cells have only been substantiated by and are due in large part to their integration in a variety of diverse spinal circuits. Chx10+V2 a interneurons play an integral role in conferring locomotion, which integrates various corticospinal, mechanosensory, and interneuron pathways. Moreover, accumulating evidence suggests that Chx10+V2 a interneurons also play an important role in rhythmic patterning maintenance, leftright alternation of central pattern generation, and locomotor pattern generation in higher order mammals, likely conferring complex locomotion. Consequently, the latest research has focused on postinjury transplantation and noninvasive stimulation of Chx10+V2 a interneurons as a therapeutic strategy, particularly in spinal cord injury. Finally, we review the latest preclinical study advances in laboratory derivation and stimulation/transplantation of these cells as a strategy for the treatment of spinal cord injury. The evidence supports that the Chx10+V2 a interneurons act as a new therapeutic target for spinal cord injury. Future optimization strategies should focus on the viability, maturity, and functional integration of Chx10+V2 a interneurons transplanted in spinal cord injury foci.

Can Hybrid Synapse be Formed between Rat Spinal Motor Neurons and Major Pelvic Ganglion Neurons in vitro?

The purpose of this study is to determine whether synapses can be formed between spinal motor neurons(SMNs)and major pelvic ganglion(MPG)neurons of a rat in vitro.The green fluorescent protein(GFP)-labelled MPG cells were cultured together with SMNs in a specific medium.The synaptic-like contacts established between SMNs and MPG neurons were studied in co-cultures using morphologic and immunocytochemistry approaches.Phase-contrast observation of co-cultures showed apparent SMNs-MPG neurons contacts as early as three or four days in vitro.We demonstrate some evidence of synaptic contacts between SMNs and MPG neurons in vitro by immunostaining with antibody directed against postsynaptic density protein 95(PSD-95).We describe the development process of a defined SMNs-MPG neurons co-culture system.The results suggest that the hybrid synapse formation that may occur between SMNs and MPG neurons in vitro played an essential role in the mechanisms of a regenerated bladder with an artificial somatic-autonomic reflex arc.

Whole-Brain Monosynaptic Inputs to Hypoglossal Motor Neurons in Mice

Hypoglossal motor neurons(HMNs) innervate tongue muscles and play key roles in a variety of physiological functions,including swallowing,mastication,suckling,vocalization,and respiration.Dysfunction of HMNs is associated with several diseases,such as obstructive sleep apnea(OSA) and sudden infant death syndrome.OS A is a serious breathing disorder associated with the activity of HMNs during different sleep-wake states.Identifying the neural mechanisms by which the statedependent activities of HMNs are controlled may be helpful in providing a theoretical basis for effective therapy for OSA.However,the presynaptic partners governing the activity of HMNs remain to be elucidated.In the present study,we used a cell-type-specific retrograde tracing system based on a modified rabies virus along with a Cre/loxP gene-expression strategy to map the whole-brain monosynaptic inputs to HMNs in mice.We identified 53 nuclei targeting HMNs from six brain regions:the amygdala,hypothalamus,midbrain,pons,medulla,and cerebellum.We discovered that GAB Aergic neurons in the central amygdaloid nucleus,as well as calretinin neurons in the parasubthalamic nucleus,sent monosynaptic projections to HMNs.In addition,HMNs received direct inputs from several regions associated with respiration,such as the preBotzinger complex,parabrachial nucleus,nucleus of the solitary tract,and hypothalamus.Some regions engaged in sleep-wake regulation(the parafacial zone,parabrachial nucleus,ventral medulla,sublaterodorsal tegmental nucleus,dorsal raphe nucleus,periaqueductal gray,and hypothalamus) also provided primary inputs to HMNs.These results contribute to further elucidating the neural circuits underlying disorders caused by the dysfunction of HMNs.

Induced pluripotent stem cell-derived motor neurons from amyotrophic lateral sclerosis(ALS)patients carrying different superoxide dismutase 1 mutations recapitulate pathological features of ALS

Background:Investigations of the pathogenic mechanisms in motor neurons(MNs)derived from amyotrophic lateral sclerosis(ALS)disease-specific induced pluripotent stem(iPS)cell lines could improve understanding of the issues affecting MNs.Therefore,in this study we explored mutant superoxide dismutase 1(SOD1)protein expression in MNs derived from the iPS cell lines of ALS patients carrying different SOD1 mutations.Methods:We generated induced pluripotent stem cell(iPSC)lines from two familial ALS(FALS)patients withSOD1-V14M andSOD1-C111Y mutations,and then differentiated them into MNs.We investigated levels of the SOD1 protein in iPSCs and MNs,the intracellular Ca2+levels in MNs,and the lactate dehydrogenase(LDH)activity in the process of differentiation into the MNs derived from the controls and ALS patients’iPSCs.Results:The iPSCs from the two FALS patients were capable of differentiation into MNs carrying different SOD1 mutations and differentially expressed MN markers.We detected high SOD1 protein expression and high intracellular calcium levels in both the MN and iPSCs that were derived from the twoSOD1 mutant patients.However,at no time did we observe stronger LDH activity in the patient lines compared with the control lines.Conclusions:MNs derived from patient-specific iPSC lines can recapitulate key aspects of ALS pathogenesis,providing a cell-based disease model to further elucidate disease pathogenesis and explore gene repair coupled with cell-replacement therapy.Incremental mutant expressions of SOD1 in MNs may have disrupted MN function,either causing or contributing to the intracellular calcium disturbances,which could lead to the occurrence and development of the disease.

Motor neuron-specific RhoA knockout delays degeneration and promotes regeneration of dendrites in spinal ventral horn after brachial plexus injury

Dendrites play irreplaceable roles in the nerve conduction pathway and are vulnerable to various insults.Peripheral axotomy of motor neurons results in the retraction of dendritic arbors,and the dendritic arbor can be re-expanded when reinnervation is allowed.RhoA is a target that regulates the cytoskeleton and promotes neuronal survival and axon regeneration.However,the role of RhoA in dendrite degeneration and regeneration is unknown.In this study,we explored the potential role of RhoA in dendrites.A line of motor neuronal conditional knockout mice was developed by crossbreeding HB9~(Cre+)mice with RhoA~(flox/flox)mice.We established two models for assaying dendrite degeneration and regeneration,in which the brachial plexus was transection or crush injured,respectively.We found that at 28 days after brachial plexus transection,the density,complexity,and structural integrity of dendrites in the ventral horn of the spinal cord of RhoA conditional knockout mice were slightly decreased compared with that in Cre mice.Dendrites underwent degeneration at 7 and 14 days after brachial plexus transection and recovered at 28–56 days.The density,complexity,and structural integrity of dendrites in the ventral horn of the spinal cord of RhoA conditional knockout mice recovered compared with results in Cre mice.These findings suggest that RhoA knockout in motor neurons attenuates dendrite degeneration and promotes dendrite regeneration after peripheral nerve injury.

Eph receptor A4 regulates motor neuron ferroptosis in spinal cord ischemia/reperfusion injury in rats

Previous studies have shown that the receptor tyrosine kinase Eph receptor A4(EphA4) is abundantly expressed in the nervous system. The EphA4 signaling pathway plays an important role in regulating motor neuron ferroptosis in motor neuron disease. To investigate whether EphA4 signaling is involved in ferroptosis in spinal cord ischemia/reperfusion injury, in this study we established a rat model of spinal cord ischemia/reperfusion injury by clamping the left carotid artery and the left subclavian artery. We found that spinal cord ischemia/reperfusion injury increased EphA4 expression in the neurons of anterior horn, markedly worsened ferroptosis-related indicators, substantially increased the number of mitochondria exhibiting features consistent with ferroptosis, promoted deterioration of motor nerve function, increased the permeability of the blood-spinal cord barrier, and increased the rate of motor neuron death. Inhibition of EphA4 largely rescued these effects. However, intrathecal administration of the ferroptosis inducer Erastin counteracted the beneficial effects conferred by treatment with the EphA4 inhibitor. Mass spectrometry and a PubMed search were performed to identify proteins that interact with EphA4, with the most notable being Beclin1 and Erk1/2. Our results showed that inhibition of EphA4 expression reduced binding to Beclin1, markedly reduced p-Beclin1, and reduced Beclin1-XCT complex formation. Inhibition of EphA4 also reduced binding to p-Erk1/2 and markedly decreased the expression of c-Myc, transferrin receptor 1, and p-Erk1/2. Additionally, we observed co-localization of EphA4 and p-Beclin1 and of EphA4 and p-ERK1/2 in neurons in the anterior horn. In conclusion, EphA4 participates in regulating ferroptosis of spinal motor neurons in the anterior horn in spinal cord ischemia/reperfusion injury by promoting formation of the Beclin1-XCT complex and activating the Erk1/2/c-Myc/transferrin receptor 1 axis.

Pathological mechanisms of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis refers to a neurodegenerative disease involving the motor system,the cause of which remains unexplained despite several years of research.Thus,the journey to understanding or treating amyotrophic lateral sclerosis is still a long one.According to current research,amyotrophic lateral sclerosis is likely not due to a single factor but rather to a combination of mechanisms mediated by complex interactions between molecular and genetic pathways.The progression of the disease involves multiple cellular processes and the interaction between different complex mechanisms makes it difficult to identify the causative factors of amyotrophic lateral sclerosis.Here,we review the most common amyotrophic lateral sclerosis-associated pathogenic genes and the pathways involved in amyotrophic lateral sclerosis,as well as summarize currently proposed potential mechanisms responsible for amyotrophic lateral sclerosis disease and their evidence for involvement in amyotrophic lateral sclerosis.In addition,we discuss current emerging strategies for the treatment of amyotrophic lateral sclerosis.Studying the emergence of these new therapies may help to further our understanding of the pathogenic mechanisms of the disease.

Alexa Fluor 488-conjugated cholera toxin subunit B optimally labels neurons 3-7 days after injection into the rat gastrocnemius muscle

Neural tract tracing is used to study neural pathways and evaluate neuronal regeneration following nerve injuries.However,it is not always clear which tracer should be used to yield optimal results.In this study,we examined the use of Alexa Fluor 488-conjugated cholera toxin subunit B(AF488-CTB).This was injected into the gastrocnemius muscle of rats,and it was found that motor,sensory,and sympathetic neurons were labeled in the spinal ventral horn,dorsal root ganglia,and sympathetic chain,respectively.Similar results were obtained when we injected AF594-CTB into the tibialis anterior muscle.The morphology and number of neurons were evaluated at different time points following the AF488-CTB injection.It was found that labeled motor and sensory neurons could be observed 12 hours post-injection.The intensity was found to increase over time,and the morphology appeared clear and complete 3-7 days post-injection,with clearly distinguishable motor neuron axons and dendrites.However,14 days after the injection,the quality of the images decreased and the neurons appeared blurred and incomplete.Nissl and immunohistochemical staining showed that the AF488-CTB-labeled neurons retained normal neurochemical and morphological features,and the surrounding microglia were also found to be unaltered.Overall,these results imply that the cholera toxin subunit B,whether unconjugated or conjugated with Alexa Fluor,is effective for retrograde tracing in muscular tissues and that it would also be suitable for evaluating the regeneration or degeneration of injured nerves.

Suicide transport blockade of motor neuron survival generates a focal graded injury and functional deficit

We describe a pre-clinical spinal cord motor neuron injury model that is minimal invasive, reproducible, focal and easily applied to small rodents.Retrograde axonal transport of a pro-apoptotic phosphatidylinosotol 3'-kinase inhibitor, wortmannin, via the sciatic nerve results in loss of ipsilateral lumbar motor neurons proportional to the level of drug administered.Motor neuron loss was detected by choline acetyltransferase(ChAT) immunostaining and with a transgenic thy1-eGFP marker.The short half-life of wortmannin generates minimal wound spread, and wortmannin does not affect axon transport, as determined by co-injection of a pseudorabies virus tracer.Using quantitative transcript analysis, we found that ChAT transcripts significantly decreased at 14 days post-delivery of 1 μg wortmannin, relative to sham controls, and remained low after 90 days.Smaller effects were observed with 200 ng and 100 ng wortmannin.Wortmannin also generated a transient and significant increase in astrocyte Gfap transcripts after 14 days with a return to control levels at 90 days.Treated mice had hind limb spasticity and a forced motor function defect that was quantified using a water exit test.Controls rapidly exit a shallow water tray, and wortmannin treated animals were up to 12-fold slower, a phenotype that persisted for at least 3 months.Thus the focal delivery of wortmannin to motor neurons generates a reproducible and scalable injury that can facilitate quantitative studies on neural regeneration and repair.The efficacy of sciatic nerve suicide transport can also explain neurotoxin-mediated selective loss of motor neurons in diseases such as amyotrophic lateral sclerosis.All procedures were performed at Rutgers under established Institutional Animal Care and Use protocols(eIACUC_TR201800022, approved on March 20, 2018).

Motor neuron replacement therapy for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is a motor neuron degenerative disease that is also known as Lou Gehrig’s disease in the United States,Charcot’s disease in France,and motor neuron disease in the UK.The loss of motor neurons causes muscle wasting,paralysis,and eventually death,which is commonly related to respiratory failure,within 3-5 years after onset of the disease.Although there are a limited number of drugs approved for amyotrophic lateral sclerosis,they have had little success at treating the associated symptoms,and they cannot reverse the course of motor neuron degeneration.Thus,there is still a lack of effective treatment for this debilitating neurodegenerative disorder.Stem cell therapy for amyotrophic lateral sclerosis is a very attractive strategy for both basic and clinical researchers,particularly as transplanted stem cells and stem cell-derived neural progenitor/precursor cells can protect endogenous motor neurons and directly replace the lost or dying motor neurons.Stem cell therapies may also be able to re-establish the motor control of voluntary muscles.Here,we review the recent progress in the use of neural stem cells and neural progenitor cells for the treatment of amyotrophic lateral sclerosis.We focus on MN progenitor cells derived from fetal central nervous system tissue,embryonic stem cells,and induced pluripotent stem cells.In our recent studies,we found that transplanted human induced pluripotent stem cell-derived motor neuron progenitors survive well,differentiate into motor neurons,and extend axons into the host white matter,not only in the rostrocaudal direction,but also along motor axon tracts towards the ventral roots in the immunodeficient rat spinal cord.Furthermore,the significant motor axonal extension after neural progenitor cell transplantation in amyotrophic lateral sclerosis models demonstrates that motor neuron replacement therapy could be a promising therapeutic strategy for amyotrophic lateral sclerosis,particularly as a variety of stem cell derivatives,including induced pluripotent stem cells,are being considered for clinical trials for various diseases.

Efficient and rapid conversion of human astrocytes and ALS mouse model spinal cord astrocytes into motor neuron-like cells by defined small molecules

Background: Motor neuron degeneration or loss in the spinal cord is the characteristic phenotype of motor neuron diseases or spinal cord injuries. Being proliferative and located near neurons, astrocytes are considered ideal cell sources for regenerating neurons.Methods: We selected and tested different combinations of the small molecules for inducing the conversion of human and mouse astrocytes into neurons. Microscopic imaging and immunocytochemistry analyses were used to characterize the morphology and phenotype of the induced neurons while RT-q PCR was utilized to analyze changes in gene expression. In addition, whole-cell patch-clamp recordings were measured to examine the electrophysiological properties of induced neurons.Results: The results showed that human astrocytes could be rapidly and efficiently converted into motor neuronlike cells by treatment with defined small molecules, with a yield of over 85% motor neuron-like cells attained. The induced motor neuron-like cells expressed the pan-neuronal markers TUJ1, MAP2, Neu N, and Synapsin 1 and motor neuron markers HB9, ISL1, CHAT, and VACh T. During the conversion process, the cells did not pass through a proliferative neural progenitor cell intermediate. The induced motor neurons were functional, showing the electrophysiological properties of neurons. The same chemical cocktail could induce spinal cord astrocytes from an amyotrophic lateral sclerosis mouse model carrying a SOD1 mutation to become motor neuron-like cells that exhibited a decrease in cell survival and an increase in oxidative stress compared to that observed in wild-type MNs derived from healthy mice. Moreover, the chemical induction reduced oxidative stress in the mutant astrocytes.Conclusions: The results of the present study demonstrated the feasibility of chemically converting human and mouse astrocytes into motor neuron-like cells that are useful for neurodegenerative disease modeling and regenerative medicine.

Cerebellar pathology in motor neuron disease:neuroplasticity and neurodegeneration

Amyotrophic lateral sclerosis is a relentlessly progressive multi-system condition.The clinical picture is dominated by upper and lower motor neuron degeneration,but extra-motor pathology is increasingly recognized,including cerebellar pathology.Post-mortem and neuroimaging studies primarily focus on the chara cterization of supratentorial disease,des pite emerging evidence of cerebellar degeneration in amyotrophic lateral sclerosis.Cardinal clinical features of amyotrophic lateral sclerosis,such as dysarthria,dysphagia,cognitive and behavioral deficits,saccade abnormalities,gait impairment,respiratory weakness and pseudobulbar affect are likely to be exacerbated by co-existing cerebellar pathology.This review summarizes in vivo and post mortem evidence for cerebellar degeneration in amyotrophic lateral scle rosis.Structural imaging studies consistently capture cerebellar grey matter volume reductions,diffusivity studies readily detect both intra-cerebellar and cerebellar peduncle white matter alte rations and functional imaging studies commonly report increased functional connectivity with supratentorial regions.Increased functional connectivity is commonly interpreted as evidence of neuro plasticity representing compensatory processes despite the lack of post-mortem validation.There is a scarcity of post-mortem studies focusing on cerebellar alte rations,but these detect pTDP-43 in cerebellar nuclei.Ce rebellar pathology is an overloo ked facet of neurodegeneration in amyotrophic lateral sclerosis despite its contribution to a multitude of clinical symptoms,wides p read connectivity to spinal and supratentorial regions and putative role in compensating for the degeneration of primary motor regions.

Lower and upper motor neuron involvement and their impact on disease prognosis in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is a fatal neurodegenerative disease characterized by progressive muscle wasting,breathing and swallowing difficulties resulting in patient’s death in two to five years after disease onset.In amyotrophic lateral sclerosis,both upper and lower motor neurons of the corticospinal tracts are involved in the process of neurodegeneration,accounting for great clinical heterogeneity of the disease.Clinical phenotype has great impact on the pattern and rate of amyotrophic lateral sclerosis progression and overall survival prognosis.Creating more homogenous patient groups in order to study the effects of drug agents on specific manifestations of the disease is a challenging issue in amyotrophic lateral sclerosis clinical trials.Since amyotrophic lateral sclerosis has low incidence rates,conduction of multicenter trials requires certain standardized approaches to disease diagnosis and staging.This review focuses on the current approaches in amyotrophic lateral sclerosis classification and staging system based on clinical examination and additional instrumental methods,highlighting the role of upper and lower motor neuron involvement in different phenotypes of the disease.We demonstrate that both clinical and instrumental findings can be useful in evaluating severity of upper motor neuron and lower motor neuron involvement and predicting the following course of the disease.Addressing disease heterogeneity in amyotrophic lateral sclerosis clinical trials could lead to study designs that will assess drug efficacy in specific patient groups,based on the disease pathophysiology and spatiotemporal pattern.Although clinical evaluation can be a sufficient screening method for dividing amyotrophic lateral sclerosis patients into clinical subgroups,we provide proof that instrumental studies could provide valuable insights in the disease pathology.

Catheter-related infections caused by Mycobacterium abscessus in a patient with motor neurone disease:A case report

BACKGROUND Mycobacterium abscessus(M.abscessus)is a rapidly growing mycobacterium and ubiquitous in the environment,which infrequently causes disease in humans.However,it can cause cutaneous or respiratory infections among immunocompromised hosts.Due to the resistance to most antibiotics,the pathogen is formidable and difficult-to-treat.CASE SUMMARY Here,we present a case of catheter-related M.abscessus infections in a patient with motor neurone disease.Catheter and peripheral blood cultures of the patient showed positive results during Gram staining and acid-fast staining.The alarm time of catheter blood culture was 10.6 h earlier than that of peripheral blood.After removal of the peripherally inserted central catheter,secretion and catheter blood culture were positive.M.abscessus was identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry and 16S rDNA sequencing.CONCLUSION For catheter-related M.abscessus infection,rapid diagnosis and timely and adequate antimicrobial therapy are crucial.