Progressive Paralysis Research Articles

Gut-Modulating Agents and Amyotrophic Lateral Sclerosis: Current Evidence and Future Perspectives.

Amyotrophic Lateral Sclerosis (ALS) is a highly fatal neurodegenerative disorder characterized by the progressive wasting and paralysis of voluntary muscle. Despite extensive research, the etiology of ALS remains elusive, and effective treatment options are limited. However, recent evidence implicates gut dysbiosis and gut-brain axis (GBA) dysfunction in ALS pathogenesis. Alterations to the composition and diversity of microbial communities within the gut flora have been consistently observed in ALS patients. These changes are often correlated with disease progression and patient outcome, suggesting that GBA modulation may have therapeutic potential. Indeed, targeting the gut microbiota has been shown to be neuroprotective in several animal models, alleviating motor symptoms and mitigating disease progression. However, the translation of these findings to human patients is challenging due to the complexity of ALS pathology and the varying diversity of gut microbiota. This review comprehensively summarizes the current literature on ALS-related gut dysbiosis, focusing on the implications of GBA dysfunction. It delineates three main mechanisms by which dysbiosis contributes to ALS pathology: compromised intestinal barrier integrity, metabolic dysfunction, and immune dysregulation. It also examines preclinical evidence on the therapeutic potential of gut-microbiota-modulating agents (categorized as prebiotics, probiotics, and postbiotics) in ALS.

Excitatory action of low frequency depolarizing GABA/glycine synaptic inputs is prevalent in prenatal spinal SOD1G93A motoneurons.

Amyotrophic lateral sclerosis (ALS) is a fatal adult-onsetneurodegenerative disease characterized by progressive motor neuron degeneration and muscle paralysis. Recent evidence suggests the dysfunction of inhibitory signalling in ALS motor neurons. We have shown that embryonic day (E)17.5spinal motoneurons (MNs) of the SOD1G93A mouse model of ALS exhibit an altered chloride homeostasis. At this prenatal stage, inhibition of spinal motoneurons (MNs) is mediated by depolarizing GABAergic/glycinergic postsynaptic potentials (dGPSPs). Here, using an ex vivo preparation and patch clamp recording from MNs with a chloride equilibrium set below spike threshold, we report that low input resistance (Rin ) E17.5 MNs from the SOD1G93A ALS mouse model do not correctly integrate dGPSPs evoked by electrical stimulations of GABA/glycine inputs at different frequencies. Indeed, firing activity of most wild-type (WT) MNs with low Rin was inhibited by incoming dGPSPs, whereas low Rin SOD1G93A MNs were excited or exhibited a dual response (excited by low frequency dGPSPs and inhibited by high frequency dGPSPs). Simulation highlighted the importance of the GABA/glycine input density and showed that pure excitation could be obtained in SOD-like MNs by moving GABA/glycine input away from the cell body to dendrites. This was in agreement with confocal imaging showing a lack of peri-somatic inhibitory terminals in SOD1G93A MNs compared to WT littermates. Putative fast ALS-vulnerable MNs with low Rin are therefore lacking functional inhibition at the near-term prenatal stage. KEY POINTS: We analysed the integration of GABAergic/glycinergic synaptic events by embryonic spinal motoneurons (MNs) in a mouse model of the amyotrophic lateral sclerosis (ALS) neurodegenerative disease. We found that GABAergic/glycinergic synaptic events do not properly inhibit ALS MNs with low input resistance, most probably corresponding to future vulnerable MNs. We used a neuron model to highlight the importance of the GABA/glycine terminal location and density in the integration of the GABAergic/glycinergic synaptic events. Confocal imaging showed a lack of GABA/glycine terminals on the cell body of ALS MNs. The present study suggests that putative ALS vulnerable MNs with low Rin lack functional inhibition at the near-term stage.

Dynamic Reconstruction Using Bilateral Lengthening Temporalis Myoplasty for Facial Palsies in Patients with Hereditary Skin Laxity.

Hereditary skin laxity is a rare condition, some cases of which are also referred to as cutis laxa, and those involving facial skin are considered a target for treatment by plastic surgery as patients present with an aged face, which can reduce their quality of life. In some of these patients, the facial nerve and muscles may be affected, and cause weakness of mimetic muscles. We performed one-stage bilateral lengthening temporalis myoplasty reanimation, followed by lower facial contouring with partial lower lip excision and hammock-shaped fascia grafting in two patients with hereditary facial skin laxity coexisting with facial palsy. The patient was a 63-year-old woman with hereditary gelsolin amyloidosis and a 64-year-old man who was diagnosed with oculopharyngeal muscular dystrophy. Postoperatively, a symmetrical facial contour was achieved in repose, and smiling with and without biting was possible. To our knowledge, there are no reports of dynamic smile reconstruction for facial weakness in patients with hereditary facial skin laxity. Although these patients may experience progressive loss of function of the trigeminal nerve and its innervating muscles, the static suspension effect of lengthening temporalis myoplasty can be expected to continue even if the temporal muscles lose their function in the future. We believe that, with careful patient selection, dynamic reconstruction is an option for progressive facial paralysis. In this article, we present the chronological history of two patients who underwent multiple plastic surgery procedures and discuss the importance of the role of plastic surgery in improving the quality of life under these conditions.

An optogenetic cell therapy to restore control of target muscles in an aggressive mouse model of amyotrophic lateral sclerosis

Breakdown of neuromuscular junctions (NMJs) is an early pathological hallmark of amyotrophic lateral sclerosis (ALS) that blocks neuromuscular transmission, leading to muscle weakness, paralysis and, ultimately, premature death. Currently, no therapies exist that can prevent progressive motor neuron degeneration, muscle denervation, or paralysis in ALS. Here, we report important advances in the development of an optogenetic, neural replacement strategy that can effectively restore innervation of severely affected skeletal muscles in the aggressive SOD1G93A mouse model of ALS, thus providing an interface to selectively control the function of targeted muscles using optical stimulation. We also identify a specific approach to confer complete survival of allogeneic replacement motor neurons. Furthermore, we demonstrate that an optical stimulation training paradigm can prevent atrophy of reinnervated muscle fibers and results in a tenfold increase in optically evoked contractile force. Together, these advances pave the way for an assistive therapy that could benefit all ALS patients.

An optogenetic cell therapy to restore control of target muscles in an aggressive mouse model of amyotrophic lateral sclerosis.

Breakdown of neuromuscular junctions (NMJs) is an early pathological hallmark of amyotrophic lateral sclerosis (ALS) that blocks neuromuscular transmission, leading to muscle weakness, paralysis and, ultimately, premature death. Currently, no therapies exist that can prevent progressive motor neuron degeneration, muscle denervation, or paralysis in ALS. Here, we report important advances in the development of an optogenetic, neural replacement strategy that can effectively restore innervation of severely affected skeletal muscles in the aggressive SOD1G93A mouse model of ALS, thus providing an interface to selectively control the function of targeted muscles using optical stimulation. We also identify a specific approach to confer complete survival of allogeneic replacement motor neurons. Furthermore, we demonstrate that an optical stimulation training paradigm can prevent atrophy of reinnervated muscle fibers and results in a tenfold increase in optically evoked contractile force. Together, these advances pave the way for an assistive therapy that could benefit all ALS patients.

Effect of Various Pathological Conditions on Nitric Oxide Level and L-Citrulline Uptake in Motor Neuron-Like (NSC-34) Cell Lines.

Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disorder that causes progressive paralysis. L-Citrulline is a non-essential neutral amino acid produced by L-arginine via nitric oxide synthase (NOS). According to previous studies, the pathogenesis of ALS entails glutamate toxicity, oxidative stress, protein misfolding, and neurofilament disruption. In addition, L-citrulline prevents neuronal cell death in brain ischemia; therefore, we investigated the change in the transport of L-citrulline under various pathological conditions in a cell line model of ALS. We examined the uptake of [14C]L-citrulline in wild-type (hSOD1wt/WT) and mutant NSC-34/ SOD1G93A (MT) cell lines. The cell viability was determined via MTT assay. A transport study was performed to determine the uptake of [14C]L-citrulline. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis was performed to determine the expression levels of rat large neutral amino acid transported 1 (rLAT1) in ALS cell lines. Nitric oxide (NO) assay was performed using Griess reagent. L-Citrulline had a restorative effect on glutamate induced cell death, and increased [14C]L-citrulline uptake and mRNA levels of the large neutral amino acid transporter (LAT1) in the glutamate-treated ALS disease model (MT). NO levels increased significantly when MT cells were pretreated with glutamate for 24 h and restored by co-treatment with L-citrulline. Co-treatment of MT cells with L-arginine, an NO donor, increased NO levels. NSC-34 cells exposed to high glucose conditions showed a significant increase in [14C]L-citrulline uptake and LAT1 mRNA expression levels, which were restored to normal levels upon co-treatment with unlabeled L-citrulline. In contrast, exposure of the MT cell line to tumor necrosis factor alpha, lipopolysaccharides, and hypertonic condition decreased the uptake significantly which was restored to the normal level by co-treating with unlabeled L-citrulline. L-Citrulline can restore NO levels and cellular uptake in ALS-affected cells with glutamate cytotoxicity, pro-inflammatory cytokines, or other pathological states, suggesting that L-citrulline supplementation in ALS may play a key role in providing neuroprotection.

AIDP BEFORE AND AFTER COVID-19 IN ALGERIA: SHORT COHORT STUDY

Acute inflammatory demyelinating polyradiculoneuropathy is an immune-mediated polyneuropathy (AIDP) that manifests in the form of an acute, ascending, areflexic, progressive and symmetrical paralysis. The primary infection usually from the respiratory or gastrointestinal tract and can be bacterial or viral, and during the pandemic SARS -COV2 and COVID-19 vaccine may also lead to it Life-threatening complications can occur as a result of Acute inflammatory demyelinating polyradiculoneuropathy Syndrome, such as: Severe Autonomic Cardiovascular Dysfunction and respiratory distress. We will report cases who were admitted to the ICU at Lamine Debaghine hospital between 2018 and 2023 presenting major complications and their evolution under ICU ward assistance. CATEGORY: Resuscitation and Anesthesia, Emergency Medicine KEYWORDS: Acute inflammatory demyelinating polyradiculoneuropathy syndrome, dysautonomia, ICU, AIDP, Guillain-Barre.

Progressive paralysis due to neurotoxin envenomation in male adolescent patient: A case report

Progressive paralysis due to neurotoxin envenomation in male adolescent patient: A case report

Multifocal thoracic intradural extramedullary anaplastic ependymoma: case report and review of the literature

BackgroundEpendymomas are neuroectodermal tumors that grow from the ependymal cells of the ventricles or the central canal of the spinal cord. When the ependymoma is anaplastic, extramedullary, intradural and multifocal, it is a very rare anatomical entity, same as case described by us.Case presentationA 44-year-old man had been admitted to our hospital for progressive paralysis of both legs over the past 5 weeks. Contrast-enhanced MRI showed intradural extramedullary tumor at T11 with cord compression and an other more little tumor at T6 level, also intradural and extramedullary. The largest lesion was completely removed by laminectomy. Histology documented an anaplastic ependymoma. Contrast-enhanced brain and spinal MRI showed the results of the previous surgery.ConclusionMultifocal intradural extramedullary anaplastic ependymomas are very rare entity. Surgery is the main treatment that can improve prognosis, while radiotherapy is useful, after surgery, in the treatment of residues, recurrences, anaplastic transformations, metastases and multifocal lesions.

Acute‐onset distal dominant neuropathy after severe acute respiratory syndrome coronavirus 2 vaccination in a male patient with recent dengue infection: A case report

AbstractObjectiveGuillain–Barré Syndrome (GBS) is an autoimmune degenerative disease commonly presenting with acute progressive sensorimotor paralysis, sometimes associated with dysautonomia, facial diplegia and severe respiratory distress. Gastroenteritis due to Campylobacter jejuni and respiratory infection secondary to Epstein–Barr virus usually precede GBS; however, vaccination or recent dengue infection as temporal causes are rarely reported.Case PresentationHere, we present a 20‐year‐old man, who complained of a 5‐day history of a progressively worsening tingling sensation isolated in the hands and feet, and unilateral Bell's palsy on the left side of his face, which occurred 2 weeks after his severe acute respiratory syndrome coronavirus 2 vaccination and 6 weeks from his recent hospitalization from Dengue fever. Except for the left complete unilateral facial paralysis, weakness in the intrinsic hands and feet muscles, and sensory ataxia, the rest of his physical examination was unremarkable. On work‐up, the findings of albuminocytological dissociation and distal sensorimotor demyelinating polyneuropathy in the nerve conduction study supported the diagnosis of GBS.ConclusionThe enhanced immune response from a recent dengue infection and severe acute respiratory syndrome coronavirus 2 vaccination might increase the risk of GBS. The predominantly distal GBS phenotype has rarely been reported in the literature, adding to the peculiarity of this case.

Progressive Lower Extremity Paralysis Caused by Intrathecal MTX-Induced Myelopathy Mimicking Guillain-Barre Syndrome: A Case Report.

Methotrexate (MTX) is commonly used in intrathecal chemotherapy for patients with acute lymphocytic leukemia (ALL) to prevent central nervous system (CNS) involvement. However, the use of MTX-based chemotherapy can lead to rare yet severe complications, such as MTX-induced myelopathy. Here, we report the case of MTX-induced myelopathy initially misdiagnosed as Guillain-Barre syndrome, leading to a delay in diagnosis and treatment. We present a case of a 39-year-old male with a history of B-cell acute lymphoblastic leukemia (B-ALL) who experienced bilateral foot paresthesia and progressive lower extremity weakness after intrathecal methotrexate (MTX) treatment. Initially, the patient was suspected as having Guillain-Barre syndrome (GBS) due to similar clinical features and nerve conduction studies. The patient received intravenous immunoglobulin (IVIG) treatment, but his condition worsened. T2-weighted images of the thoracic spinal cord revealed high signal intensity in both lateral and posterior columns, typically associated with subacute combined degeneration. However, elevated vitamin B12 levels ruled out SCD in this case. Based on the aforementioned findings, intrathecal methotrexate-induced myelopathy was diagnosed. This case highlights the diagnostic challenge posed by the similarity in clinical presentation between MTX-induced myelopathy and GBS. Differentiating between these conditions is critical for appropriate management. Prompt recognition and treatment with folate metabolism compounds may mitigate neurological sequelae.

Neuroprotective effect of biogenically synthesized ZnO nanoparticles against oxidative stress and β-amyloid toxicity in transgenic Caenorhabditis elegans.

Amyloid β (Aβ) plaque accumulation-mediated neuronal toxicity has been suggested to cause synaptic damage and consequent degeneration of brain cells in Alzheimer's disease (AD). With the increasing prerequisite of eco-friendly nanoparticles (NPs), research investigators are utilizing green approaches for the synthesis of zinc oxide (ZnO) NPs for pharmaceutical applications. In this present study, ZnO NPs were synthesized from Acanthus ilicifolius to assess the neuroprotective properties in the AD model of transgenic Caenorhabditis elegans strains CL2006 and CL4176 expressing Aβ aggregation. Our findings revealed that the therapeutic effect of green-synthesized ZnO NPs is associated with antioxidant activity. We also found that ZnO NPs significantly enhance the C. elegan's lifespan, locomotion, pharyngeal pumping, chemotaxis behavior also diminish the ROS deposition and intracellular productionMoreover, thioflavin T staining demonstrated that ZnO NPs substantially attenuated the Aβ deposition in the C. elegans strain as compared to untreated worms. With their antioxidant properties, the greenly synthesized ZnO NPs had a significant neuroprotective efficiency on Aβ-induced toxicity by reducing Aβ aggregation and specifically reducing the progression of paralysis in the C. elegans AD model. Our findings suggested that the biosynthesized ZnO NPs could be thought-provoking candidates for age-associated neurodegenerative disorders accompanied by oxidative stress.

Pitts-Hoppkins Syndrome Post Severe Exacerbation of Asthma: About a Case: 3-Year-Old Child

In some children recovering from an acute asthma attack, flaccid paralysis similar to poliomyelitis has been observed [1-3]. This condition, first discovered in Australia in 1974, is known as Hopkins Syndrome (HS) [4]. No specific virus was identified in these patients, who were usually correctly vaccinated against poliomyelitis [5]. This disorder primarily affects cells in the anterior horn of the spinal cord. It is characterized by a rapid progression of paralysis usually affecting one limb, leaving the child with severe and permanent weakness. Sensation is usually preserved, and Cerebrospinal Fluid (CSF) analysis often shows a slight increase in white blood cells and a slight increase in protein [6-8]. Magnetic Resonance Imaging (MRI) alterations in the anterior horn have been documented [9]. Some children show signs of an underlying immune deficiency [10]. We report the case of a 3-year-old boy who presented with an episode of Hopkins syndrome.

NRF2 signaling cascade in amyotrophic lateral sclerosis: bridging the gap between promise and reality.

Amyotrophic lateral sclerosis is a very disabling disease due to the degeneration of motor neurons. Symptoms include muscle weakness and atrophy, spasticity, and progressive paralysis. Currently, there is no treatment to reverse damage to motor neurons and cure amyotrophic lateral sclerosis. The only two treatments actually approved, riluzole and edaravone, have shown mitigated beneficial effects. The difficulty to find a cure lies in the complexity and multifaceted pattern of amyotrophic lateral sclerosis pathogenesis. Among mechanisms, abnormal RNA metabolism, nucleocytoplasmic transport defects, accumulation of unfolded protein, and mitochondrial dysfunction would in fine induce oxidative damage and vice versa. A potent therapeutic strategy will be to find molecules that break this vicious circle. Sharpening the nuclear factor erythroid-2 related factor 2 signaling may fulfill this objective since nuclear factor erythroid-2 related factor 2 has a multitarget profile controlling antioxidant defense, mitochondrial functioning, and inflammation. We here discuss the interest of developing nuclear factor erythroid-2 related factor 2-based therapy in regard to the pathophysiological mechanisms and we provide a general overview of the attempted clinical assays in amyotrophic lateral sclerosis.

AFB1 induced free radicals cause encephalopathy in goat kids via intrinsic pathway of apoptosis: pathological and immunohistochemical confirmation of non-hepatic neuroaflatoxicosis.

Aflatoxins, particularly AFB1, are the most common feed contaminants worldwide, causing significant economic losses to the livestock sector. The current paper describes an outbreak of aflatoxicosis in a herd of 160 male young goat kids (3-4 months), of which 68 young kids succumbed over a period of 25 days after showing neurological signs of abnormal gait, progressive paralysis and head pressing. The haematobiochemical investigation showed reduced haemoglobin, leucocyte count, PCV level, increased levels of AST, ALT, glucose, BUN, creatinine and reduced level of total protein. Grossly, kids had pale mucous membranes, pale and swollen liver; right apical lobe consolidation, and petechiation of the synovial membrane of the hock joints. The microscopic changes were characterized by multifocal hemorrhages, status spongiosus/ vacuolation, vasculitis, focal to diffuse gliosis, satellitosis, and ischemic apoptotic neurons in different parts of the brain and spinal cord. These changes corresponded well with strong immunoreactivity for AFB1 in neurons, glia cells (oligodendrocytes, astrocytes, and ependymal cells) in various anatomical sites of the brain. The higher values of LPO and reduced levels of antioxidant enzymes (Catalase, SOD, GSH) with strong immunoreactivity of 8-OHdG in the brain indicating high level of oxidative stress. Further, the higher immunosignaling of caspase-3 and caspase-9 in the brain points towards the association with intrinsic pathway of apoptosis. The toxicological analysis of feed samples detected high amounts of AFB1 (0.38ppm). These findings suggest that AFB1 in younger goat kids has more of neurotoxic effect mediated through caspase dependent intrinsic pathway.

Digital measures of respiratory and upper limb function in spinal muscular atrophy: design, feasibility, reliability, and preliminary validity of a smartphone sensor-based assessment suite

Spinal muscular atrophy (SMA) is characterized by progressive muscle weakness and paralysis. Motor function is monitored in the clinical setting using assessments including the 32-item Motor Function Measure (MFM-32), but changes in disease severity between clinical visits may be missed. Digital health technologies may assist evaluation of disease severity by bridging gaps between clinical visits. We developed a smartphone sensor-based assessment suite, comprising nine tasks, to assess motor and muscle function in people with SMA. We used data from the risdiplam phase 2 JEWELFISH trial to assess the test–retest reliability and convergent validity of each task. In the first 6 weeks, 116 eligible participants completed assessments on a median of 6.3 days per week. Eight of the nine tasks demonstrated good or excellent test–retest reliability (intraclass correlation coefficients >0.75 and >0.9, respectively). Seven tasks showed a significant association (P < 0.05) with related clinical measures of motor function (individual items from the MFM-32 or Revised Upper Limb Module scales) and seven showed significant association (P < 0.05) with disease severity measured using the MFM-32 total score. This cross-sectional study supports the feasibility, reliability, and validity of using smartphone-based digital assessments to measure function in people living with SMA.

Registry of Patients with Spinal Muscular Atrophy in a Tertiary Care Unit in Egypt

Background Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease characterized by degeneration of alpha motor neurons in the spinal cord, resulting in progressive proximal muscle weakness and paralysis. Objectives To register patients with SMA who are diagnosed clinically and genetically (typical and atypical forms) in a tertiary care unit in Egypt. Patient and methods 80 Patients with SMA who are diagnosed clinically and genetically at Neuromuscular Unit of Ain Shams University Hospital were registered. Demographical data and genetics of the patients were collected and analyzed. The patients were assessed for skeletal deformities, cardiac evaluation by echo and pulmonary evaluation by PFTs (for patients above 5 years old) and functional assessment by motor scales according to age and type of each patient was done. Results SMA was more common in males with predominance of type II and median age of 4.5 years old, a considerable number of cases had positive history of consanguinity and similar cases in family, 98.8% of cases had the typical form of SMA with homozygous deletion of SMN1 gene with variable SMN2 copy number according to type. 32.5% of cases had skeletal deformities in the form of scoliosis with or without kyphosis, extremities contractures and chest cave deformities. 4 cases had restrictive pattern due to scoliosis cardiac abnormalities were detected in 3 cases of type I. 31 cases were assessed by CHOP INTEND and 49 cases were assessed by HFMSE giving a good tool for assessing disease progress and role of physiotherapy. Severe chest infection and respiratory failure was the cause of death of 3 cases of type I during the period of study. Conclusion registry of SMA patients will lead to a better understanding of the natural history of SMA and the influence of drug treatment. This is crucial to improve the care of SMA patients.

Guillain-Barré Syndrome Complicated by Posterior Reversible Encephalopathy Syndrome and Reversible Cerebral Vasoconstriction Syndrome.

Guillain-Barré syndrome is an immune-mediated inflammatory polyneuritis characterised by rapidly progressive flaccid paralysis. Guillain-Barré syndrome may present with posterior reversible encephalopathy syndrome or reversible cerebral vasoconstriction syndrome in rare cases. A woman in her 60s with a history of follicular lymphoma presented with a one-week history of difficulty walking and thunderclap headaches. The patient was diagnosed with Guillain-Barré syndrome based on neurological examination, cerebrospinal fluid analysis and nerve conduction findings. Further diagnosis of posterior reversible encephalopathy and reversible cerebral vasoconstriction syndromes was based on imaging findings and headache history. The patient was treated with intravenous immunoglobulin and amlodipine, and symptoms improved. We reviewed the literature on Guillain-Barré syndrome associated with posterior reversible encephalopathy and/or reversible cerebral vasoconstriction syndrome. The underlying pathophysiology may involve dysautonomia resulting in unstable blood pressure, and hyponatraemia causing endothelial dysfunction. The SNOOP mnemonic highlights the 'red flags'. This SNOOP mnemonic suggests the possibility of secondary headaches that require imaging studies. In this case, the patient exhibited three SNOOP symptoms: S (history of malignancy: follicular lymphoma), O (sudden-onset headache) and O (over 50 years old). This case highlights the importance of considering coexisting central neurological disorders in patients with Guillain-Barré syndrome. Guillain-Barré syndrome (GBS) alone rarely causes headaches; therefore, when GBS patients complain of severe headaches, especially when the headache is associated with 'red flags', other complications and differential diagnosis should be considered.Posterior reversible encephalopathy syndrome (PRES) and reversible cerebral vasoconstriction syndrome (RCVS) can be triggered by GBS.Hyponatraemia, age over 50 years and female gender may be risk factors for developing PRES and RCVS in GBS patients.

An impaired splicing program underlies differentiation defects in hSOD1G93A neural progenitor cells.

Amyotrophic lateral sclerosis (ALS) is an adult devastating neurodegenerative disease characterized by the loss of upper and lower motor neurons (MNs), resulting in progressive paralysis and death. Genetic animal models of ALS have highlighted dysregulation of synaptic structure and function as a pathogenic feature of ALS-onset and progression. Alternative pre-mRNA splicing (AS), which allows expansion of the coding power of genomes by generating multiple transcript isoforms from each gene, is widely associated with synapse formation and functional specification. Deciphering the link between aberrant splicing regulation and pathogenic features of ALS could pave the ground for novel therapeutic opportunities. Herein, we found that neural progenitor cells (NPCs) derived from the hSOD1G93A mouse model of ALS displayed increased proliferation and propensity to differentiate into neurons. In parallel, hSOD1G93A NPCs showed impaired splicing patterns in synaptic genes, which could contribute to the observed phenotype. Remarkably, master splicing regulators of the switch from stemness to neural differentiation are de-regulated in hSOD1G93A NPCs, thus impacting the differentiation program. Our data indicate that hSOD1G93A mutation impacts on neurogenesis by increasing the NPC pool in the developing mouse cortex and affecting their intrinsic properties, through the establishment of a specific splicing program.

Unwinding the role of Wnt signaling cascade and molecular triggers of motor neuron degeneration in amyotrophic lateral sclerosis (ALS)

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative condition, triggered by various factors causing the degeneration of upper and lower motor neurons, resulting in progressive muscle wasting, paralysis, and death. Multiple in vivo and in vitro models have been established to unravel the molecular events leading to the deterioration of motor neurons in ALS. The canonical and non-canonical Wnt signaling pathway has been implicated to play a crucial role in the progression of neurodegenerative disorders. This review discusses the role of Wnt signaling in the reported causes of ALS such as oxidative stress, mitochondrial dysfunction, autophagy, and apoptosis. Mutations in ALS-associated genes such as SOD1, C9orf72, TDP43, FUS, and OPTN cause an imbalance in neuronal integrity and homeostasis leading to motor neuron demise. Wnt signaling is also observed to play a crucial role in the muscle sparing of oculomotor neurons. The non-canonical Wnt/Ca2+ pathway which regulates intrinsic electrophysiological properties and mobilizes calcium ions to maintain neuronal integrity has been found to be altered in the stem cell-derived ALS model. Thus, the interplay of dysregulated canonical and non-canonical Wnt pathways in multiple motor neuron disease models has shown that Wnt contributes to disease progression indicating it to be utilized as a potential target for ALS.