RARE DISEASE
Charcot-Marie-Tooth disease type 4C
Charcot-Marie-Tooth disease type 4C
Charcot-Marie-Tooth disease type 4C
Synonyms: CMT4C
Synonyms: CMT4C
Synonyms: CMT4C
Drug discovery
71
papers
On emerging therapies
Overview
Charcot-Marie-Tooth disease type 4C (CMT4C) is an autosomal recessive demyelinating neuropathy caused by SH3TC2 gene mutations. It typically presents in childhood with progressive scoliosis, distal limb weakness, sensory deficits, and variable cranial nerve involvement (e.g., facial paresis, hearing loss). Nerve conduction velocities are slowed (16–36 m/s), and skeletal deformities (e.g., pes cavus) are common. Disease progression varies, often necessitating mobility aids by adulthood [1][4][8][10].
Categories: rare genetic diseases, rare neurological diseases
Research Papers
71 drug discovery papers about Charcot-Marie-Tooth disease type 4C, with 1 first-in-class emerging drug candidate forecasted to outperform the average preclinical success rate. Recent publications:
71 drug discovery papers about Charcot-Marie-Tooth disease type 4C, with 1 first-in-class emerging drug candidate forecasted to outperform the average preclinical success rate. Recent publications:
categories:
Small molecules
small molecules
2024-03-14 | Gp78 regulates PMP22 and causes ER stress and autophagy in EV71-VP1-overexpressing mouse Schwann cells
Background: During Enterovirus type 71 (EV71) infection, the structural viral protein 1 (VP1) activates endoplasmic reticulum (ER) stress associated with peripheral myelin protein 22 (PMP22) accumulation and induces autophagy.However, the specific mechanism behind this process remains elusive.Methods: In this research, we used the VP1-overexpressing mouse Schwann cells (SCs) models co-transfected with a PMP22 silencing or Autocrine motility factor receptor (AMFR/gp78) overexpressing vector to explore the regulation of gp78 on PMP22 and its relationship with autophagy and apoptosis.Results: The activity of gp78 could be influenced by EV71-VP1, leading to a decrease in the ubiquitination and degradation of PMP22, resulting in PMP22 accumulation in ER.In VP1overexpressing mouse SCs, all three ER stress sensors, including pancreatic endoplasmic reticulum kinase (PERK), activating transcription factor 6 (ATF6) and inositol-requiring enzyme 1 (IRE1) and the related downstream signals (C/EBP-homologous protein (CHOP) and Caspase 12) were activated, as well as the ER-resident chaperone Glucoseregulated protein 78 (GRP78).In addition, VP1 upregulated the autophagy marker Microtubule-associated protein 1 light chain 3 beta (LC3B), while PMP22 silencing or gp78 overexpression reversed the phenomenon.Meanwhile, PMP22 silencing or gp78 overexpression increased proliferation of EV71-VP1-transfected mouse SCs.Conclusion:Gp78 could regulate PMP22 accumulation through ubiquitination degradation and cause ER stress and autophagy in EV71-VP1-overexpressing mouse SCs.Therefore, the gp78/PMP22/ER stress axis might emerge as a promising therapeutic target for myelin and neuronal damage induced by EV71 infection.
2023-11-16 | Schwann cell-specific ablation of Beclin 1 impairs peripheral myelination and leads to a progressive motor and sensory neuropathy
Abstract The core component of the class III phosphatidylinositol 3-kinase complex, Beclin 1, takes part in different protein networks, thus switching its role from inducing autophagy to regulating autophagosomal maturation and endosomal trafficking. While assessed in neurons, astrocytes and microglia, its role was far less investigated in myelinating glia, including Schwann cells (SCs), responsible for peripheral nerve myelination. Remarkably, the dysregulation in endosomal trafficking is emerging as a pathophysiological mechanism underlying peripheral neuropathies, such as demyelinating Charcot-Marie-Tooth diseases. By knocking out Beclin 1 in SCs we here generated a novel mouse model ( Becn1 cKO), developing a severe and progressive neuropathy, accompanied by involuntary tremors, body weight loss and premature death. Ultrastructural analysis revealed abated myelination and SCs displaying enlarged cytoplasm with progressive accumulation of intracellular vesicles. Transcriptomic and histological analysis from sciatic nerves of 10-day and 2-month-old mice revealed pro-mitotic gene deregulation and increased SCs proliferation at both stages with axonal loss and increased immune infiltration in adults, well reflecting the progressive motor and sensory functional impairment that characterizes Becn1 cKO mice, compared to controls. Our study establishes a further step in understanding key mechanisms in SC development and points to Beclin 1 and its regulated pathways as targets for demyelinating CMT forms.
2023-09-01 | Charcot Marie Tooth disease type 4C with overlap of chronic infammatory demyelinating polyneuropathy: a case report
Case presentation: Patient female, born of a cousin marriage with history of respiratory distress at birth requiring orotracheal intubation and was diagnosed with dysphagia requiring gastrostomy for 1 year. Presented neuropsychomotor developmental delay and at the age of 6 started with symptoms of paraesthesias and lower limbs cramps. At the age of 12, the patient presented muscle weakness and pain in the lower limbs with progressive worsening associated with frequent falls. The patient was referred to our service at the age of 13 years old. At clinical evaluation, the patient could easily stand up, initiate independent gait, with a wide-based gait and tendency to fall. She could stand without support for a short period of time. Presented Grade III muscle strength in lower limbs and grade IV in the upper limbs associated with hypotrophy in lower limbs and at reflex and sensitivity examinations presented hypoactive osteotendinous reflexes in upper limbs and absent in lower limbs with distally reduced sensitivity in the lower limbs. Electroneuromyography demonstrated severe peripheral sensorimotor demyelinating polyneuropathy and cerebrospinal fluid shown hiperproteynorraquia. During follow-up, the patient presented an unstable course of symptoms, with worsen of weakness especially in association with an infectious condition. Therefore, pulse therapy with steroids was chosen as a treatment, with expressive improvement of the clinical symptoms. PMP22 genetic test was performed, which ruled out Charcot Marie Tooth type 1A. An expansion of the genetic test was performed, which revealed CMT4C alteration with mutation in the SH3TC2 gene.
2023-07-21 | Amlexanox: Readthrough Induction and Nonsense-Mediated mRNA Decay Inhibition in a Charcot–Marie–Tooth Model of hiPSCs-Derived Neuronal Cells Harboring a Nonsense Mutation in GDAP1 Gene
Nonsense mutations are involved in multiple peripheral neuropathies. These mutations induce the presence of a premature termination codon (PTC) at the mRNA level. As a result, a dysfunctional or truncated protein is synthesized, or even absent linked to nonsense-mediated mRNA degradation (NMD) system activation. Readthrough molecules or NMD inhibitors could be innovative therapies in these hereditary neuropathies, particularly molecules harboring the dual activity as amlexanox. Charcot–Marie–Tooth (CMT) is the most common inherited pathology of the peripheral nervous system, affecting 1 in 2500 people worldwide. Nonsense mutations in the GDAP1 gene have been associated with a severe form of CMT, prompting us to investigate the effect of readthrough and NMD inhibitor molecules. Although not clearly defined, GDAP1 could be involved in mitochondrial functions, such as mitophagy. We focused on the homozygous c.581C>G (p.Ser194*) mutation inducing CMT2H using patient human induced pluripotent stem cell (hiPSC)-derived neuronal cells. Treatment during 20 h with 100 µM of amlexanox on this cell model stabilized GDAP1 mRNAs carrying UGA-PTC and induced a restoration of the mitochondrial morphology. These results highlight the potential of readthrough molecules associated to NMD inhibitors for the treatment of genetic alterations in CMT, opening the way for future investigations and a potential therapy.
2022-03-23 | The autophagy inducer SMER28 attenuates microtubule dynamics mediating neuroprotection
Abstract SMER28 was originally identified in a screen for small-molecules that act as modulators of autophagy. SMER28 enhanced the clearance of autophagic substrates such as mutant huntingtin, an effect that was independent of rapamycin-induced autophagy. Thus, SMER 28 was established as a positive regulator of autophagy acting independently of the mTOR pathway, increasing autophagosome biosynthesis and attenuating mutant huntingtin-fragment toxicity in cellular- and fruit fly Huntington’s disease models, suggesting therapeutic potential. Despite a wealth of previous studies, molecular mechanisms mediating SMER28 activities and its direct targets have remained elusive. Here we analyzed the effects of SMER28 on cells and found that it not only induces autophagy, but also significantly stabilizes microtubules and decelerates microtubule dynamics. Moreover, we report that SMER28 displays neurotrophic and neuroprotective effects at the cellular level by inducing neurite outgrowth and by protecting from excitotoxin-induced axon degeneration. Finally, we compare the effects of SMER28 with other autophagy-inducing or microtubule-stabilizing drugs: Whereas SMER28 and rapamycin both induce autophagy, the latter does not stabilize microtubules, and whereas both SMER28 and epothilone B stabilize microtubules, epothilone does not provoke increased autophagy. Thus, the effect of SMER28 on cells in general and neurons in particular is based on its unique spectrum of bioactivities distinct from other known microtubule-stabilizing or autophagy-inducing drugs.
proteins
2024-11-15 | AAV1.tMCK.NT-3 gene therapy improves phenotype in Sh3tc2-/- mouse model of Charcot-Marie-Tooth Type 4C.
Charcot-Marie-Tooth Type 4C (CMT4C) is associated with mutations in the SH3 domain and tetratricopeptide repeats 2 (SH3TC2) gene, primarily expressed in Schwann cells (SCs). Neurotrophin-3 (NT-3) is an important autocrine factor for SC survival and differentiation, and it stimulates neurite outgrowth and myelination. In this study, scAAV1.tMCK.NT-3 was delivered intramuscularly to 4-week-old Sh3tc2-/- mice, a model for CMT4C, and treatment efficacy was assessed at 6-month post-gene delivery. Efficient transgene production was verified with the detection of NT-3 in serum from the treated cohort. NT-3 gene therapy improved functional and electrophysiological outcomes including rotarod, grip strength and nerve conduction velocity. Qualitative and quantitative histopathological studies showed that hypomyelination of peripheral nerves and denervated status of neuromuscular junctions at lumbrical muscles were also improved in the NT-3-treated mice. Morphometric analysis in mid-sciatic and tibial nerves showed treatment-induced distally prominent regenerative activity in the nerve and an increase in the estimated SC density. This indicates that SC proliferation and differentiation, including the promyelination stage, are normal in the Sh3tc2-/- mice, consistent with the previous findings that Sh3tc2 is not involved in the early stages of myelination. Moreover, in size distribution histograms, the number of myelinated axons within the 3- to 6-µm diameter range increased, suggesting that treatment resulted in continuous radial growth of regenerating axons over time. In conclusion, this study demonstrates the efficacy of AAV1.NT-3 gene therapy in the Sh3tc2-/- mouse model of CMT4C, the most common recessively inherited demyelinating CMT subtype.
2023-10-17 | Neurotrophin-3 promotes peripheral nerve regeneration by maintaining a repair state of Schwann cells after chronic denervation via the TrkC/ERK/c-Jun pathway
Maintaining the repair phenotype of denervated Schwann cells in the injured distal nerve is crucial for promoting peripheral nerve regeneration. However, when chronically denervated, the capacity of Schwann cells to support repair and regeneration deteriorates, leading to peripheral nerve regeneration and poor functional recovery. Herein, we investigated whether neurotrophin-3 (NT-3) could sustain the reparative phenotype of Schwann cells and promote peripheral nerve regeneration after chronic denervation and aimed to uncover its potential molecular mechanisms.Western blot was employed to investigate the relationship between the expression of c-Jun and the reparative phenotype of Schwann cells. The inducible expression of c-Jun by NT-3 was examined both in vitro and in vivo with western blot and immunofluorescence staining. A chronic denervation model was established to study the role of NT-3 in peripheral nerve regeneration. The number of regenerated distal axons, myelination of regenerated axons, reinnervation of neuromuscular junctions, and muscle fiber diameters of target muscles were used to evaluate peripheral nerve regeneration by immunofluorescence staining, transmission electron microscopy (TEM), and hematoxylin and eosin (H&E) staining. Adeno-associated virus (AAV) 2/9 carrying shRNA, small molecule inhibitors, and siRNA were employed to investigate whether NT-3 could signal through the TrkC/ERK pathway to maintain c-Jun expression and promote peripheral nerve regeneration after chronic denervation.After peripheral nerve injury, c-Jun expression progressively increased until week 5 and then began to decrease in the distal nerve following denervation. NT-3 upregulated the expression of c-Jun in denervated Schwann cells, both in vitro and in vivo. NT-3 promoted peripheral nerve regeneration after chronic denervation, mainly by upregulating or maintaining a high level of c-Jun rather than NT-3 itself. The TrkC receptor was consistently presented on denervated Schwann cells and served as NT-3 receptors following chronic denervation. NT-3 mainly upregulated c-Jun through the TrkC/ERK pathway.NT-3 promotes peripheral nerve regeneration by maintaining the repair phenotype of Schwann cells after chronic denervation via the TrkC/ERK/c-Jun pathway. It provides a potential target for the clinical treatment of peripheral nerve injury after chronic denervation.
2023-06-01 | Cytokine-Induced Neurogenesis in Charcot-Marie-Tooth neuropathy with Connexin 32 Gene Mutation
Charcot-Marie-Tooth (CMT) neuropathy is one of the most common neuromuscular disorders.Despite the identification of more than 100 causative genes, there are few therapeutic options.We present the case of a 66-year-old man carrying a CMT mutation in the connexin 32 gene with the APOE genotype ε4/ε3 that had exhibited symptoms of slowly progressive muscle weakness and atrophy in the hands and feet and recently developed memory impairment.The muscle weakness, motor dysfunction, and memory impairment symptoms were significantly improved by cytokine-induced neurogenesis combined with physical wave therapy using an arbitrary waveform generator (AWG).Here, we discuss the possible mechanistic basis of how this new treatment ameliorates the symptoms of CMT and propose a novel clinical treatment strategy for CMT.
2019-08-06 | Follistatin-based ligand trap ACE-083 induces localized hypertrophy of skeletal muscle with functional improvement in models of neuromuscular disease
Abstract Skeletal muscle is under inhibitory homeostatic regulation by multiple ligands of the transforming growth factor-β (TGFβ) superfamily. Follistatin is a secreted protein that promotes muscle growth and function by sequestering these ligands extracellularly. In the present study, we evaluated the potential of ACE-083 – a locally acting, follistatin-based fusion protein – as a novel therapeutic agent for focal or asymmetric myopathies. Characterization of ACE-083 in vitro revealed its high affinity for heparin and extracellular matrix while surface plasmon resonance and cell-based assays confirmed that ACE-083 binds and potently neutralizes myostatin, activin A, activin B and growth differentiation factor 11 (GDF11). Intramuscular administration of ACE-083 caused localized, dose-dependent hypertrophy of the injected muscle in wild-type mice and mouse models of Charcot-Marie-Tooth disease (CMT) and Duchenne muscular dystrophy, with no evidence of systemic muscle effects or endocrine perturbation. Importantly, ACE-083 also increased the force of isometric contraction in situ by the injected tibialis anterior muscle in wild-type mice and disease models and increased ankle dorsiflexion torque in CMT mice. Our results demonstrate the potential of ACE-083 as a therapeutic agent for patients with CMT, muscular dystrophy and other disorders with focal or asymmetric muscle atrophy or weakness.
2019-06-27 | Mitochondrial impairment activates the Wallerian pathway through depletion of NMNAT2 leading to SARM1-dependent axon degeneration
ABSTRACT Wallerian degeneration of physically injured axons involves a well-defined molecular pathway linking loss of axonal survival factor NMNAT2 to activation of pro-degenerative protein SARM1. Manipulating the pathway through these proteins led to the identification of non-axotomy insults causing axon degeneration by a Wallerian-like mechanism, including several involving mitochondrial impairment. Mitochondrial dysfunction is heavily implicated in Parkinson’s disease, Charcot-Marie-Tooth disease, hereditary spastic paraplegia and other axonal disorders. However, whether and how mitochondrial impairment activates Wallerian degeneration has remained unclear. Here, we show that disruption of mitochondrial membrane potential leads to axonal NMNAT2 depletion in mouse sympathetic neurons, increasing the substrate-to-product ratio (NMN/NAD) of this NAD-synthesising enzyme, a metabolic fingerprint of Wallerian degeneration. The mechanism appears to involve both impaired NMNAT2 synthesis and reduced axonal transport. Expression of WLD S and Sarm1 deletion both protect axons after mitochondrial uncoupling. Blocking the pathway also confers neuroprotection and increases the lifespan of flies with Pink1 loss-of-function mutation, which causes severe mitochondrial defects. These data indicate that mitochondrial impairment replicates all the major steps of Wallerian degeneration, placing it upstream of NMNAT2 loss, with the potential to contribute to axon pathology in mitochondrial disorders.
gene therapies
2026-05-13 | A dose-escalation and safety gene therapy study in a model of CMT4C neuropathy.
Charcot-Marie-Tooth disease type 4C is a demyelinating neuropathy caused by loss of function mutations in the SH3TC2 gene, that is highly expressed in myelinating Schwann cells. We generated and tested a clinical stage vector with a minimal human MPZ promoter driving expression of SH3TC2. Groups of 1-month old Sh3tc2-/- mice were treated with 3 different doses of AAV9-hMPZmini.SH3TC2.SV40pA or the formulation buffer by lumbar intrathecal injection. Outcomes were compared 8 weeks post injection by behavioral, electrophysiological, proteomics, morphological analysis and evaluation of tissue integrity and inflammatory responses. Vector biodistribution to the peripheral nerves and high rates of cell-specific therapeutic gene expression in Schwann cells resulted in significant therapeutic benefits in the CMT4C model. Treated mice showed improved motor performance in grip strength and motor nerve conduction velocities. Morphological analysis revealed significant improvement in g-ratios, myelin thickness and ratios of demyelinated fibers in lumbar roots and femoral nerves of treated mice. Proteomic profiles showed correction of muscle denervation associated pathobiochemical processes in treated mice. Not observed tissue toxicity or immune reactions in neural tissues or peripheral organs. This study provides proof of principle for dose-dependent effectiveness and safety of intrathecal AAV9-mediated gene replacement paving the way for clinical translation.
2026-01-13 | A dose-escalation and safety study of gene therapy for CMT4C neuropathy
Charcot-Marie-Tooth disease type 4C is a demyelinating neuropathy caused by loss of function mutations in the SH3TC2 gene, that is highly expressed in myelinating Schwann cells. We generated and tested a clinical stage vector with a minimal human MPZ promoter driving expression of SH3TC2 . Groups of 1-month old Sh3tc2 −/− mice were treated with 3 different doses of AAV9- hMPZmini.SH3TC2.SV40pA or the formulation buffer by lumbar intrathecal injection. Outcomes were compared 8 weeks post injection by behavioral, electrophysiological, proteomics, morphological analysis and evaluation of tissue integrity and inflammatory responses. Vector biodistribution to the peripheral nerves and high rates of cell-specific therapeutic gene expression in Schwann cells resulted in significant therapeutic benefits in the CMT4C model. Treated mice showed improved motor performance in grip strength, rotarod testing and motor nerve conduction velocities. Morphological analysis revealed significant improvement in g-ratios, myelin thickness and ratios of demyelinated fibers in lumbar roots and femoral nerves of treated mice. Proteomic profiles showed correction of muscle denervation associated pathobiochemical processes in treated mice. Not observed tissue toxicity or immune reactions in neural tissues or peripheral organs. This study provides proof of principle for dose-dependent effectiveness and safety of intrathecal AAV9-mediated gene replacement paving the way for clinical translation.
2025-08-01 | Nationwide Phenotypic and Genotypic Characterisation of 103 Patients With SH3TC2 Gene-Related Demyelinating Peripheral Neuropathy.
Autosomal recessive mutations in the SH3TC2 gene cause Charcot-Marie-Tooth type 4C (CMT4C) demyelinating peripheral neuropathy. In this nationwide observational retrospective study involving 27 French University Hospitals, we analyzed the clinical, electrophysiological, and genetic features of 103 patients from 89 families with homozygous and compound heterozygous SH3TC2 gene mutations identified between 2003 and 2023. Mean age was 42 years (2-80), and 49% of patients were female. Mean age at disease onset was 14 years (0-52), 60% of patients started the disease before age 10 years, and 24% after age 20 years. Patients presented with distal motor weakness (93% of cases), sensory loss (86%), foot deformities (83%), scoliosis (73%), proximal limb weakness (40%), cranial nerve involvement (48%), hearing loss (37%), scoliosis-related respiratory insufficiency (14%), and genitourinary disorders (6%). Half the patients (48%) walked independently before age 50 years, in contrast with only 13% after age 50 years. After age 50 years, 23% of patients were wheelchair-bound. Nerve conduction studies showed sensorimotor abnormalities within the demyelinating range in all cases. We identified 56 different pathogenic variants in the SH3TC2 gene, including 22 previously undescribed. Patients with two SH3TC2 gene truncating variants had more severe symptoms than patients with one or zero truncating variants. This study shows CMT4C is a severe childhood- and adult-onset demyelinating peripheral neuropathy often associated with scoliosis, hearing loss, and ambulation loss in a significant proportion of patients after age 50 years. Genotype-phenotype correlations suggest two truncating SH3TC2 gene variants cause a more severe phenotype.
2023-11-27 | AAV9-mediated SH3TC2 gene replacement therapy targeted to Schwann cells for the treatment of CMT4C.
Type 4C Charcot-Marie-Tooth (CMT4C) demyelinating neuropathy is caused by autosomal recessive SH3TC2 gene mutations. SH3TC2 is highly expressed in myelinating Schwann cells. CMT4C is a childhood-onset progressive disease without effective treatment. Here, we generated a gene therapy for CMT4C mediated by an adeno-associated viral 9 vector (AAV9) to deliver the human SH3TC2 gene in the Sh3tc2-/- mouse model of CMT4C. We used a minimal fragment of the myelin protein zero (Mpz) promoter (miniMpz), which was cloned and validated to achieve Schwann cell-targeted expression of SH3TC2. Following the demonstration of AAV9-miniMpz.SH3TC2myc vector efficacy to re-establish SH3TC2 expression in the peripheral nervous system, we performed an early as well as a delayed treatment trial in Sh3tc2-/- mice. We demonstrate both after early as well as following late treatment improvements in multiple motor performance tests and nerve conduction velocities. Moreover, treatment led to normalization of the organization of the nodes of Ranvier, which is typically deficient in CMT4C patients and Sh3tc2-/- mice, along with reduced ratios of demyelinated fibers, increased myelin thickness and reduced g-ratios at both time points of intervention. Taken together, our results provide a proof of concept for an effective and potentially translatable gene replacement therapy for CMT4C treatment.
2023-09-22 | Clinical trials in Charcot-Marie-Tooth disorders: a retrospective and preclinical assessment
This study aimed to evaluate the progression of clinical and preclinical trials in Charcot-Marie-Tooth (CMT) disorders.CMT has historically been managed symptomatically and with genetic counseling. The evolution of molecular and pathologic understanding holds a therapeutic promise in gene-targeted therapies.ClinicalTrials.gov from December 1999 to June 2022 was data extracted for CMT with preclinical animal gene therapy trials also reviewed by PubMed search.The number of active trials was 1 in 1999 and 286 in 2022. Academic settings accounted for 91% and pharmaceutical companies 9%. Of the pharmaceutical and academic trials, 38% and 28%, respectively, were controlled, randomized, and double-blinded. Thirty-two countries participated: the United States accounted for 26% (75/286). In total, 86% of the trials were classified as therapeutic: 50% procedural (21% wrist/elbow surgery; 22% shock wave and hydrodissection therapy), 23% investigational drugs, 15% devices, and 11% physical therapy. Sixty-seven therapeutic trials (49%) were designated phases 1-2 and 51% phases 3-4. The remaining 14% represent non-therapeutic trials: diagnostic testing (3%), functional outcomes (4%), natural history (4%), and standard of care (3%). One-hundred and three (36%) resulted in publications. Phase I human pharmaceutical trials are focusing on the safety of small molecule therapies (n = 8) and AAV and non-viral gene therapy (n = 3). Preclinical animal gene therapy studies include 11 different CMT forms including viral, CRISPR-Cas9, and nanoparticle delivery.Current CMT trials are exploring procedural and molecular therapeutic options with substantial participation of the pharmaceutical industry worldwide. Emerging drug therapies directed at molecular pathogenesis are being advanced in human clinical trials; however, the majority remain within animal investigations.
cell therapies
2025-02-13 | Addressing myelination disorders: Novel strategies using human 3D peripheral nerve model.
Peripheral myelination disorders encompass a variety of disorders that affect myelin sheaths in the peripheral nervous system. The Charcot-Marie-Tooth disease (CMT), the most common inherited peripheral neuropathy, is one of the most prevalent among them. CMT stems from a wide range of genetic causes that disrupt the nerve conduction, leading to progressive muscle weakness and atrophy, sensory loss, and motor function impairment. Historically, the study of these disorders has relied heavily on animal studies, owing to the challenges in accessing human cells. However, the advent of human induced pluripotent stem cell (hiPSC)-derived neuronal cells has addressed these limitations in the realm of peripheral myelination disorders. Despite this, obtaining myelin in these models remains an expensive, time-consuming, and material-intensive process. This study presents a novel, cost-effective method utilizing hiPSC-derived Schwann cells and motor neurons in a three-dimensional culture system. Our method successfully enabled the acquisition of myelin in a control clone within just four weeks, as confirmed by electron microscopy. Furthermore, the utility of these approaches was validated by studying CMT4C, also named AR-CMTde-SH3TC2, the most common recessive demyelinating form of CMT. This revealed defects in Schwann cell support to motor neuron neurite outgrowth and impaired myelination in disease-specific hiPSC-derived lines. This approach offers valuable insights into the pathogenesis of peripheral myelination disorders and provides a platform for testing potential therapeutic strategies.
2021-11-06 | Stem Cell Therapy Enhances Motor Activity of Triceps Surae Muscle in Mice with Hereditary Peripheral Neuropathy
Impaired motor and sensory functions are the main features of Charcot-Marie-Tooth disease. Mesenchymal stem cell (MSCs) therapy is one of the possible treatments for this disease. It was assumed that MSCs therapy can improve the contractile properties of the triceps surae (TS) muscles in mice with hereditary peripheral neuropathy. Murine adipose-derived mesenchymal stromal cells (AD-MSCs) were obtained for transplantation into TS muscles of FVB-C-Tg(GFPU)5Nagy/J mice. Three months after AD-MSCs transplantation, animals were subjected to electrophysiological investigations. Parameters of TS muscle tension after intermittent high frequency electrical sciatic nerve stimulations were analyzed. It was found that force of TS muscle tension contraction in animals after AD-MSCs treatment was two-time higher than in untreated mice. Normalized values of force muscle contraction in different phases of electrical stimulation were 0.3 ± 0.01 vs. 0.18 ± 0.01 and 0.26 ± 0.03 vs. 0.13 ± 0.03 for treated and untreated animals, respectively. It is assumed that the two-fold increase in TS muscle strength was caused by stem cell therapy. Apparently, AD-MSCs therapy can promote nerve regeneration and partial restoration of muscle function, and thus can be a potential therapeutic agent for the treatment of peripheral neuropathies.
2017-01-09 | Direct Conversion of Human Fibroblasts into Schwann Cells that Facilitate Regeneration of Injured Peripheral Nerve In Vivo
Abstract Schwann cells (SCs) play pivotal roles in the maintenance and regeneration of the peripheral nervous system. Although transplantation of SCs enhances repair of experimentally damaged peripheral and central nerve tissues, it is difficult to prepare a sufficient number of functional SCs for transplantation therapy without causing adverse events for the donor. Here, we generated functional SCs by somatic cell reprogramming procedures and demonstrated their capability to promote peripheral nerve regeneration. Normal human fibroblasts were phenotypically converted into SCs by transducing SOX10 and Krox20 genes followed by culturing for 10 days resulting in approximately 43% directly converted Schwann cells (dSCs). The dSCs expressed SC-specific proteins, secreted neurotrophic factors, and induced neuronal cells to extend neurites. The dSCs also displayed myelin-forming capability both in vitro and in vivo. Moreover, transplantation of the dSCs into the transected sciatic nerve in mice resulted in significantly accelerated regeneration of the nerve and in improved motor function at a level comparable to that with transplantation of the SCs obtained from a peripheral nerve. The dSCs induced by our procedure may be applicable for novel regeneration therapy for not only peripheral nerve injury but also for central nerve damage and for neurodegenerative disorders related to SC dysfunction.
other
2023-07-06 | Controllable mitochondrial aggregation and fusion by a programmable DNA binder
DNA nanodevices have been feasibly applied for various chemo-biological applications, but their functions as precise regulators of intracellular organelles are still limited. Here, we report a synthetic DNA binder that can artificially induce mitochondrial aggregation and fusion in living cells. The rationally designed DNA binder consists of a long DNA chain, which is grafted with multiple mitochondria-targeting modules. Our results indicated that the DNA binder-induced in situ self-assembly of mitochondria can be used to successfully repair ROS-stressed neuron cells. Meanwhile, this DNA binder design is highly programmable. Customized molecular switches can be easily implanted to further achieve stimuli-triggered mitochondrial aggregation and fusion inside living cells. We believe this new type of DNA regulator system will become a powerful chemo-biological tool for subcellular manipulation and precision therapy.
small molecules
2024-03-14 | Gp78 regulates PMP22 and causes ER stress and autophagy in EV71-VP1-overexpressing mouse Schwann cells
Background: During Enterovirus type 71 (EV71) infection, the structural viral protein 1 (VP1) activates endoplasmic reticulum (ER) stress associated with peripheral myelin protein 22 (PMP22) accumulation and induces autophagy.However, the specific mechanism behind this process remains elusive.Methods: In this research, we used the VP1-overexpressing mouse Schwann cells (SCs) models co-transfected with a PMP22 silencing or Autocrine motility factor receptor (AMFR/gp78) overexpressing vector to explore the regulation of gp78 on PMP22 and its relationship with autophagy and apoptosis.Results: The activity of gp78 could be influenced by EV71-VP1, leading to a decrease in the ubiquitination and degradation of PMP22, resulting in PMP22 accumulation in ER.In VP1overexpressing mouse SCs, all three ER stress sensors, including pancreatic endoplasmic reticulum kinase (PERK), activating transcription factor 6 (ATF6) and inositol-requiring enzyme 1 (IRE1) and the related downstream signals (C/EBP-homologous protein (CHOP) and Caspase 12) were activated, as well as the ER-resident chaperone Glucoseregulated protein 78 (GRP78).In addition, VP1 upregulated the autophagy marker Microtubule-associated protein 1 light chain 3 beta (LC3B), while PMP22 silencing or gp78 overexpression reversed the phenomenon.Meanwhile, PMP22 silencing or gp78 overexpression increased proliferation of EV71-VP1-transfected mouse SCs.Conclusion:Gp78 could regulate PMP22 accumulation through ubiquitination degradation and cause ER stress and autophagy in EV71-VP1-overexpressing mouse SCs.Therefore, the gp78/PMP22/ER stress axis might emerge as a promising therapeutic target for myelin and neuronal damage induced by EV71 infection.
2023-11-16 | Schwann cell-specific ablation of Beclin 1 impairs peripheral myelination and leads to a progressive motor and sensory neuropathy
Abstract The core component of the class III phosphatidylinositol 3-kinase complex, Beclin 1, takes part in different protein networks, thus switching its role from inducing autophagy to regulating autophagosomal maturation and endosomal trafficking. While assessed in neurons, astrocytes and microglia, its role was far less investigated in myelinating glia, including Schwann cells (SCs), responsible for peripheral nerve myelination. Remarkably, the dysregulation in endosomal trafficking is emerging as a pathophysiological mechanism underlying peripheral neuropathies, such as demyelinating Charcot-Marie-Tooth diseases. By knocking out Beclin 1 in SCs we here generated a novel mouse model ( Becn1 cKO), developing a severe and progressive neuropathy, accompanied by involuntary tremors, body weight loss and premature death. Ultrastructural analysis revealed abated myelination and SCs displaying enlarged cytoplasm with progressive accumulation of intracellular vesicles. Transcriptomic and histological analysis from sciatic nerves of 10-day and 2-month-old mice revealed pro-mitotic gene deregulation and increased SCs proliferation at both stages with axonal loss and increased immune infiltration in adults, well reflecting the progressive motor and sensory functional impairment that characterizes Becn1 cKO mice, compared to controls. Our study establishes a further step in understanding key mechanisms in SC development and points to Beclin 1 and its regulated pathways as targets for demyelinating CMT forms.
2023-09-01 | Charcot Marie Tooth disease type 4C with overlap of chronic infammatory demyelinating polyneuropathy: a case report
Case presentation: Patient female, born of a cousin marriage with history of respiratory distress at birth requiring orotracheal intubation and was diagnosed with dysphagia requiring gastrostomy for 1 year. Presented neuropsychomotor developmental delay and at the age of 6 started with symptoms of paraesthesias and lower limbs cramps. At the age of 12, the patient presented muscle weakness and pain in the lower limbs with progressive worsening associated with frequent falls. The patient was referred to our service at the age of 13 years old. At clinical evaluation, the patient could easily stand up, initiate independent gait, with a wide-based gait and tendency to fall. She could stand without support for a short period of time. Presented Grade III muscle strength in lower limbs and grade IV in the upper limbs associated with hypotrophy in lower limbs and at reflex and sensitivity examinations presented hypoactive osteotendinous reflexes in upper limbs and absent in lower limbs with distally reduced sensitivity in the lower limbs. Electroneuromyography demonstrated severe peripheral sensorimotor demyelinating polyneuropathy and cerebrospinal fluid shown hiperproteynorraquia. During follow-up, the patient presented an unstable course of symptoms, with worsen of weakness especially in association with an infectious condition. Therefore, pulse therapy with steroids was chosen as a treatment, with expressive improvement of the clinical symptoms. PMP22 genetic test was performed, which ruled out Charcot Marie Tooth type 1A. An expansion of the genetic test was performed, which revealed CMT4C alteration with mutation in the SH3TC2 gene.
2023-07-21 | Amlexanox: Readthrough Induction and Nonsense-Mediated mRNA Decay Inhibition in a Charcot–Marie–Tooth Model of hiPSCs-Derived Neuronal Cells Harboring a Nonsense Mutation in GDAP1 Gene
Nonsense mutations are involved in multiple peripheral neuropathies. These mutations induce the presence of a premature termination codon (PTC) at the mRNA level. As a result, a dysfunctional or truncated protein is synthesized, or even absent linked to nonsense-mediated mRNA degradation (NMD) system activation. Readthrough molecules or NMD inhibitors could be innovative therapies in these hereditary neuropathies, particularly molecules harboring the dual activity as amlexanox. Charcot–Marie–Tooth (CMT) is the most common inherited pathology of the peripheral nervous system, affecting 1 in 2500 people worldwide. Nonsense mutations in the GDAP1 gene have been associated with a severe form of CMT, prompting us to investigate the effect of readthrough and NMD inhibitor molecules. Although not clearly defined, GDAP1 could be involved in mitochondrial functions, such as mitophagy. We focused on the homozygous c.581C>G (p.Ser194*) mutation inducing CMT2H using patient human induced pluripotent stem cell (hiPSC)-derived neuronal cells. Treatment during 20 h with 100 µM of amlexanox on this cell model stabilized GDAP1 mRNAs carrying UGA-PTC and induced a restoration of the mitochondrial morphology. These results highlight the potential of readthrough molecules associated to NMD inhibitors for the treatment of genetic alterations in CMT, opening the way for future investigations and a potential therapy.
2022-03-23 | The autophagy inducer SMER28 attenuates microtubule dynamics mediating neuroprotection
Abstract SMER28 was originally identified in a screen for small-molecules that act as modulators of autophagy. SMER28 enhanced the clearance of autophagic substrates such as mutant huntingtin, an effect that was independent of rapamycin-induced autophagy. Thus, SMER 28 was established as a positive regulator of autophagy acting independently of the mTOR pathway, increasing autophagosome biosynthesis and attenuating mutant huntingtin-fragment toxicity in cellular- and fruit fly Huntington’s disease models, suggesting therapeutic potential. Despite a wealth of previous studies, molecular mechanisms mediating SMER28 activities and its direct targets have remained elusive. Here we analyzed the effects of SMER28 on cells and found that it not only induces autophagy, but also significantly stabilizes microtubules and decelerates microtubule dynamics. Moreover, we report that SMER28 displays neurotrophic and neuroprotective effects at the cellular level by inducing neurite outgrowth and by protecting from excitotoxin-induced axon degeneration. Finally, we compare the effects of SMER28 with other autophagy-inducing or microtubule-stabilizing drugs: Whereas SMER28 and rapamycin both induce autophagy, the latter does not stabilize microtubules, and whereas both SMER28 and epothilone B stabilize microtubules, epothilone does not provoke increased autophagy. Thus, the effect of SMER28 on cells in general and neurons in particular is based on its unique spectrum of bioactivities distinct from other known microtubule-stabilizing or autophagy-inducing drugs.
proteins
2024-11-15 | AAV1.tMCK.NT-3 gene therapy improves phenotype in Sh3tc2-/- mouse model of Charcot-Marie-Tooth Type 4C.
Charcot-Marie-Tooth Type 4C (CMT4C) is associated with mutations in the SH3 domain and tetratricopeptide repeats 2 (SH3TC2) gene, primarily expressed in Schwann cells (SCs). Neurotrophin-3 (NT-3) is an important autocrine factor for SC survival and differentiation, and it stimulates neurite outgrowth and myelination. In this study, scAAV1.tMCK.NT-3 was delivered intramuscularly to 4-week-old Sh3tc2-/- mice, a model for CMT4C, and treatment efficacy was assessed at 6-month post-gene delivery. Efficient transgene production was verified with the detection of NT-3 in serum from the treated cohort. NT-3 gene therapy improved functional and electrophysiological outcomes including rotarod, grip strength and nerve conduction velocity. Qualitative and quantitative histopathological studies showed that hypomyelination of peripheral nerves and denervated status of neuromuscular junctions at lumbrical muscles were also improved in the NT-3-treated mice. Morphometric analysis in mid-sciatic and tibial nerves showed treatment-induced distally prominent regenerative activity in the nerve and an increase in the estimated SC density. This indicates that SC proliferation and differentiation, including the promyelination stage, are normal in the Sh3tc2-/- mice, consistent with the previous findings that Sh3tc2 is not involved in the early stages of myelination. Moreover, in size distribution histograms, the number of myelinated axons within the 3- to 6-µm diameter range increased, suggesting that treatment resulted in continuous radial growth of regenerating axons over time. In conclusion, this study demonstrates the efficacy of AAV1.NT-3 gene therapy in the Sh3tc2-/- mouse model of CMT4C, the most common recessively inherited demyelinating CMT subtype.
2023-10-17 | Neurotrophin-3 promotes peripheral nerve regeneration by maintaining a repair state of Schwann cells after chronic denervation via the TrkC/ERK/c-Jun pathway
Maintaining the repair phenotype of denervated Schwann cells in the injured distal nerve is crucial for promoting peripheral nerve regeneration. However, when chronically denervated, the capacity of Schwann cells to support repair and regeneration deteriorates, leading to peripheral nerve regeneration and poor functional recovery. Herein, we investigated whether neurotrophin-3 (NT-3) could sustain the reparative phenotype of Schwann cells and promote peripheral nerve regeneration after chronic denervation and aimed to uncover its potential molecular mechanisms.Western blot was employed to investigate the relationship between the expression of c-Jun and the reparative phenotype of Schwann cells. The inducible expression of c-Jun by NT-3 was examined both in vitro and in vivo with western blot and immunofluorescence staining. A chronic denervation model was established to study the role of NT-3 in peripheral nerve regeneration. The number of regenerated distal axons, myelination of regenerated axons, reinnervation of neuromuscular junctions, and muscle fiber diameters of target muscles were used to evaluate peripheral nerve regeneration by immunofluorescence staining, transmission electron microscopy (TEM), and hematoxylin and eosin (H&E) staining. Adeno-associated virus (AAV) 2/9 carrying shRNA, small molecule inhibitors, and siRNA were employed to investigate whether NT-3 could signal through the TrkC/ERK pathway to maintain c-Jun expression and promote peripheral nerve regeneration after chronic denervation.After peripheral nerve injury, c-Jun expression progressively increased until week 5 and then began to decrease in the distal nerve following denervation. NT-3 upregulated the expression of c-Jun in denervated Schwann cells, both in vitro and in vivo. NT-3 promoted peripheral nerve regeneration after chronic denervation, mainly by upregulating or maintaining a high level of c-Jun rather than NT-3 itself. The TrkC receptor was consistently presented on denervated Schwann cells and served as NT-3 receptors following chronic denervation. NT-3 mainly upregulated c-Jun through the TrkC/ERK pathway.NT-3 promotes peripheral nerve regeneration by maintaining the repair phenotype of Schwann cells after chronic denervation via the TrkC/ERK/c-Jun pathway. It provides a potential target for the clinical treatment of peripheral nerve injury after chronic denervation.
2023-06-01 | Cytokine-Induced Neurogenesis in Charcot-Marie-Tooth neuropathy with Connexin 32 Gene Mutation
Charcot-Marie-Tooth (CMT) neuropathy is one of the most common neuromuscular disorders.Despite the identification of more than 100 causative genes, there are few therapeutic options.We present the case of a 66-year-old man carrying a CMT mutation in the connexin 32 gene with the APOE genotype ε4/ε3 that had exhibited symptoms of slowly progressive muscle weakness and atrophy in the hands and feet and recently developed memory impairment.The muscle weakness, motor dysfunction, and memory impairment symptoms were significantly improved by cytokine-induced neurogenesis combined with physical wave therapy using an arbitrary waveform generator (AWG).Here, we discuss the possible mechanistic basis of how this new treatment ameliorates the symptoms of CMT and propose a novel clinical treatment strategy for CMT.
2019-08-06 | Follistatin-based ligand trap ACE-083 induces localized hypertrophy of skeletal muscle with functional improvement in models of neuromuscular disease
Abstract Skeletal muscle is under inhibitory homeostatic regulation by multiple ligands of the transforming growth factor-β (TGFβ) superfamily. Follistatin is a secreted protein that promotes muscle growth and function by sequestering these ligands extracellularly. In the present study, we evaluated the potential of ACE-083 – a locally acting, follistatin-based fusion protein – as a novel therapeutic agent for focal or asymmetric myopathies. Characterization of ACE-083 in vitro revealed its high affinity for heparin and extracellular matrix while surface plasmon resonance and cell-based assays confirmed that ACE-083 binds and potently neutralizes myostatin, activin A, activin B and growth differentiation factor 11 (GDF11). Intramuscular administration of ACE-083 caused localized, dose-dependent hypertrophy of the injected muscle in wild-type mice and mouse models of Charcot-Marie-Tooth disease (CMT) and Duchenne muscular dystrophy, with no evidence of systemic muscle effects or endocrine perturbation. Importantly, ACE-083 also increased the force of isometric contraction in situ by the injected tibialis anterior muscle in wild-type mice and disease models and increased ankle dorsiflexion torque in CMT mice. Our results demonstrate the potential of ACE-083 as a therapeutic agent for patients with CMT, muscular dystrophy and other disorders with focal or asymmetric muscle atrophy or weakness.
2019-06-27 | Mitochondrial impairment activates the Wallerian pathway through depletion of NMNAT2 leading to SARM1-dependent axon degeneration
ABSTRACT Wallerian degeneration of physically injured axons involves a well-defined molecular pathway linking loss of axonal survival factor NMNAT2 to activation of pro-degenerative protein SARM1. Manipulating the pathway through these proteins led to the identification of non-axotomy insults causing axon degeneration by a Wallerian-like mechanism, including several involving mitochondrial impairment. Mitochondrial dysfunction is heavily implicated in Parkinson’s disease, Charcot-Marie-Tooth disease, hereditary spastic paraplegia and other axonal disorders. However, whether and how mitochondrial impairment activates Wallerian degeneration has remained unclear. Here, we show that disruption of mitochondrial membrane potential leads to axonal NMNAT2 depletion in mouse sympathetic neurons, increasing the substrate-to-product ratio (NMN/NAD) of this NAD-synthesising enzyme, a metabolic fingerprint of Wallerian degeneration. The mechanism appears to involve both impaired NMNAT2 synthesis and reduced axonal transport. Expression of WLD S and Sarm1 deletion both protect axons after mitochondrial uncoupling. Blocking the pathway also confers neuroprotection and increases the lifespan of flies with Pink1 loss-of-function mutation, which causes severe mitochondrial defects. These data indicate that mitochondrial impairment replicates all the major steps of Wallerian degeneration, placing it upstream of NMNAT2 loss, with the potential to contribute to axon pathology in mitochondrial disorders.
gene therapies
2026-05-13 | A dose-escalation and safety gene therapy study in a model of CMT4C neuropathy.
Charcot-Marie-Tooth disease type 4C is a demyelinating neuropathy caused by loss of function mutations in the SH3TC2 gene, that is highly expressed in myelinating Schwann cells. We generated and tested a clinical stage vector with a minimal human MPZ promoter driving expression of SH3TC2. Groups of 1-month old Sh3tc2-/- mice were treated with 3 different doses of AAV9-hMPZmini.SH3TC2.SV40pA or the formulation buffer by lumbar intrathecal injection. Outcomes were compared 8 weeks post injection by behavioral, electrophysiological, proteomics, morphological analysis and evaluation of tissue integrity and inflammatory responses. Vector biodistribution to the peripheral nerves and high rates of cell-specific therapeutic gene expression in Schwann cells resulted in significant therapeutic benefits in the CMT4C model. Treated mice showed improved motor performance in grip strength and motor nerve conduction velocities. Morphological analysis revealed significant improvement in g-ratios, myelin thickness and ratios of demyelinated fibers in lumbar roots and femoral nerves of treated mice. Proteomic profiles showed correction of muscle denervation associated pathobiochemical processes in treated mice. Not observed tissue toxicity or immune reactions in neural tissues or peripheral organs. This study provides proof of principle for dose-dependent effectiveness and safety of intrathecal AAV9-mediated gene replacement paving the way for clinical translation.
2026-01-13 | A dose-escalation and safety study of gene therapy for CMT4C neuropathy
Charcot-Marie-Tooth disease type 4C is a demyelinating neuropathy caused by loss of function mutations in the SH3TC2 gene, that is highly expressed in myelinating Schwann cells. We generated and tested a clinical stage vector with a minimal human MPZ promoter driving expression of SH3TC2 . Groups of 1-month old Sh3tc2 −/− mice were treated with 3 different doses of AAV9- hMPZmini.SH3TC2.SV40pA or the formulation buffer by lumbar intrathecal injection. Outcomes were compared 8 weeks post injection by behavioral, electrophysiological, proteomics, morphological analysis and evaluation of tissue integrity and inflammatory responses. Vector biodistribution to the peripheral nerves and high rates of cell-specific therapeutic gene expression in Schwann cells resulted in significant therapeutic benefits in the CMT4C model. Treated mice showed improved motor performance in grip strength, rotarod testing and motor nerve conduction velocities. Morphological analysis revealed significant improvement in g-ratios, myelin thickness and ratios of demyelinated fibers in lumbar roots and femoral nerves of treated mice. Proteomic profiles showed correction of muscle denervation associated pathobiochemical processes in treated mice. Not observed tissue toxicity or immune reactions in neural tissues or peripheral organs. This study provides proof of principle for dose-dependent effectiveness and safety of intrathecal AAV9-mediated gene replacement paving the way for clinical translation.
2025-08-01 | Nationwide Phenotypic and Genotypic Characterisation of 103 Patients With SH3TC2 Gene-Related Demyelinating Peripheral Neuropathy.
Autosomal recessive mutations in the SH3TC2 gene cause Charcot-Marie-Tooth type 4C (CMT4C) demyelinating peripheral neuropathy. In this nationwide observational retrospective study involving 27 French University Hospitals, we analyzed the clinical, electrophysiological, and genetic features of 103 patients from 89 families with homozygous and compound heterozygous SH3TC2 gene mutations identified between 2003 and 2023. Mean age was 42 years (2-80), and 49% of patients were female. Mean age at disease onset was 14 years (0-52), 60% of patients started the disease before age 10 years, and 24% after age 20 years. Patients presented with distal motor weakness (93% of cases), sensory loss (86%), foot deformities (83%), scoliosis (73%), proximal limb weakness (40%), cranial nerve involvement (48%), hearing loss (37%), scoliosis-related respiratory insufficiency (14%), and genitourinary disorders (6%). Half the patients (48%) walked independently before age 50 years, in contrast with only 13% after age 50 years. After age 50 years, 23% of patients were wheelchair-bound. Nerve conduction studies showed sensorimotor abnormalities within the demyelinating range in all cases. We identified 56 different pathogenic variants in the SH3TC2 gene, including 22 previously undescribed. Patients with two SH3TC2 gene truncating variants had more severe symptoms than patients with one or zero truncating variants. This study shows CMT4C is a severe childhood- and adult-onset demyelinating peripheral neuropathy often associated with scoliosis, hearing loss, and ambulation loss in a significant proportion of patients after age 50 years. Genotype-phenotype correlations suggest two truncating SH3TC2 gene variants cause a more severe phenotype.
2023-11-27 | AAV9-mediated SH3TC2 gene replacement therapy targeted to Schwann cells for the treatment of CMT4C.
Type 4C Charcot-Marie-Tooth (CMT4C) demyelinating neuropathy is caused by autosomal recessive SH3TC2 gene mutations. SH3TC2 is highly expressed in myelinating Schwann cells. CMT4C is a childhood-onset progressive disease without effective treatment. Here, we generated a gene therapy for CMT4C mediated by an adeno-associated viral 9 vector (AAV9) to deliver the human SH3TC2 gene in the Sh3tc2-/- mouse model of CMT4C. We used a minimal fragment of the myelin protein zero (Mpz) promoter (miniMpz), which was cloned and validated to achieve Schwann cell-targeted expression of SH3TC2. Following the demonstration of AAV9-miniMpz.SH3TC2myc vector efficacy to re-establish SH3TC2 expression in the peripheral nervous system, we performed an early as well as a delayed treatment trial in Sh3tc2-/- mice. We demonstrate both after early as well as following late treatment improvements in multiple motor performance tests and nerve conduction velocities. Moreover, treatment led to normalization of the organization of the nodes of Ranvier, which is typically deficient in CMT4C patients and Sh3tc2-/- mice, along with reduced ratios of demyelinated fibers, increased myelin thickness and reduced g-ratios at both time points of intervention. Taken together, our results provide a proof of concept for an effective and potentially translatable gene replacement therapy for CMT4C treatment.
2023-09-22 | Clinical trials in Charcot-Marie-Tooth disorders: a retrospective and preclinical assessment
This study aimed to evaluate the progression of clinical and preclinical trials in Charcot-Marie-Tooth (CMT) disorders.CMT has historically been managed symptomatically and with genetic counseling. The evolution of molecular and pathologic understanding holds a therapeutic promise in gene-targeted therapies.ClinicalTrials.gov from December 1999 to June 2022 was data extracted for CMT with preclinical animal gene therapy trials also reviewed by PubMed search.The number of active trials was 1 in 1999 and 286 in 2022. Academic settings accounted for 91% and pharmaceutical companies 9%. Of the pharmaceutical and academic trials, 38% and 28%, respectively, were controlled, randomized, and double-blinded. Thirty-two countries participated: the United States accounted for 26% (75/286). In total, 86% of the trials were classified as therapeutic: 50% procedural (21% wrist/elbow surgery; 22% shock wave and hydrodissection therapy), 23% investigational drugs, 15% devices, and 11% physical therapy. Sixty-seven therapeutic trials (49%) were designated phases 1-2 and 51% phases 3-4. The remaining 14% represent non-therapeutic trials: diagnostic testing (3%), functional outcomes (4%), natural history (4%), and standard of care (3%). One-hundred and three (36%) resulted in publications. Phase I human pharmaceutical trials are focusing on the safety of small molecule therapies (n = 8) and AAV and non-viral gene therapy (n = 3). Preclinical animal gene therapy studies include 11 different CMT forms including viral, CRISPR-Cas9, and nanoparticle delivery.Current CMT trials are exploring procedural and molecular therapeutic options with substantial participation of the pharmaceutical industry worldwide. Emerging drug therapies directed at molecular pathogenesis are being advanced in human clinical trials; however, the majority remain within animal investigations.
cell therapies
2025-02-13 | Addressing myelination disorders: Novel strategies using human 3D peripheral nerve model.
Peripheral myelination disorders encompass a variety of disorders that affect myelin sheaths in the peripheral nervous system. The Charcot-Marie-Tooth disease (CMT), the most common inherited peripheral neuropathy, is one of the most prevalent among them. CMT stems from a wide range of genetic causes that disrupt the nerve conduction, leading to progressive muscle weakness and atrophy, sensory loss, and motor function impairment. Historically, the study of these disorders has relied heavily on animal studies, owing to the challenges in accessing human cells. However, the advent of human induced pluripotent stem cell (hiPSC)-derived neuronal cells has addressed these limitations in the realm of peripheral myelination disorders. Despite this, obtaining myelin in these models remains an expensive, time-consuming, and material-intensive process. This study presents a novel, cost-effective method utilizing hiPSC-derived Schwann cells and motor neurons in a three-dimensional culture system. Our method successfully enabled the acquisition of myelin in a control clone within just four weeks, as confirmed by electron microscopy. Furthermore, the utility of these approaches was validated by studying CMT4C, also named AR-CMTde-SH3TC2, the most common recessive demyelinating form of CMT. This revealed defects in Schwann cell support to motor neuron neurite outgrowth and impaired myelination in disease-specific hiPSC-derived lines. This approach offers valuable insights into the pathogenesis of peripheral myelination disorders and provides a platform for testing potential therapeutic strategies.
2021-11-06 | Stem Cell Therapy Enhances Motor Activity of Triceps Surae Muscle in Mice with Hereditary Peripheral Neuropathy
Impaired motor and sensory functions are the main features of Charcot-Marie-Tooth disease. Mesenchymal stem cell (MSCs) therapy is one of the possible treatments for this disease. It was assumed that MSCs therapy can improve the contractile properties of the triceps surae (TS) muscles in mice with hereditary peripheral neuropathy. Murine adipose-derived mesenchymal stromal cells (AD-MSCs) were obtained for transplantation into TS muscles of FVB-C-Tg(GFPU)5Nagy/J mice. Three months after AD-MSCs transplantation, animals were subjected to electrophysiological investigations. Parameters of TS muscle tension after intermittent high frequency electrical sciatic nerve stimulations were analyzed. It was found that force of TS muscle tension contraction in animals after AD-MSCs treatment was two-time higher than in untreated mice. Normalized values of force muscle contraction in different phases of electrical stimulation were 0.3 ± 0.01 vs. 0.18 ± 0.01 and 0.26 ± 0.03 vs. 0.13 ± 0.03 for treated and untreated animals, respectively. It is assumed that the two-fold increase in TS muscle strength was caused by stem cell therapy. Apparently, AD-MSCs therapy can promote nerve regeneration and partial restoration of muscle function, and thus can be a potential therapeutic agent for the treatment of peripheral neuropathies.
2017-01-09 | Direct Conversion of Human Fibroblasts into Schwann Cells that Facilitate Regeneration of Injured Peripheral Nerve In Vivo
Abstract Schwann cells (SCs) play pivotal roles in the maintenance and regeneration of the peripheral nervous system. Although transplantation of SCs enhances repair of experimentally damaged peripheral and central nerve tissues, it is difficult to prepare a sufficient number of functional SCs for transplantation therapy without causing adverse events for the donor. Here, we generated functional SCs by somatic cell reprogramming procedures and demonstrated their capability to promote peripheral nerve regeneration. Normal human fibroblasts were phenotypically converted into SCs by transducing SOX10 and Krox20 genes followed by culturing for 10 days resulting in approximately 43% directly converted Schwann cells (dSCs). The dSCs expressed SC-specific proteins, secreted neurotrophic factors, and induced neuronal cells to extend neurites. The dSCs also displayed myelin-forming capability both in vitro and in vivo. Moreover, transplantation of the dSCs into the transected sciatic nerve in mice resulted in significantly accelerated regeneration of the nerve and in improved motor function at a level comparable to that with transplantation of the SCs obtained from a peripheral nerve. The dSCs induced by our procedure may be applicable for novel regeneration therapy for not only peripheral nerve injury but also for central nerve damage and for neurodegenerative disorders related to SC dysfunction.
other
2023-07-06 | Controllable mitochondrial aggregation and fusion by a programmable DNA binder
DNA nanodevices have been feasibly applied for various chemo-biological applications, but their functions as precise regulators of intracellular organelles are still limited. Here, we report a synthetic DNA binder that can artificially induce mitochondrial aggregation and fusion in living cells. The rationally designed DNA binder consists of a long DNA chain, which is grafted with multiple mitochondria-targeting modules. Our results indicated that the DNA binder-induced in situ self-assembly of mitochondria can be used to successfully repair ROS-stressed neuron cells. Meanwhile, this DNA binder design is highly programmable. Customized molecular switches can be easily implanted to further achieve stimuli-triggered mitochondrial aggregation and fusion inside living cells. We believe this new type of DNA regulator system will become a powerful chemo-biological tool for subcellular manipulation and precision therapy.
Access all drug discovery papers and probability of success in trials forecasts:
Access all drug discovery papers and probability of success in trials forecasts:
Drug Discovery Landscape
0 orphan drug designations.
0 orphan drug designations.
Let's accelerate rare disease drug discovery
Let's accelerate drug discovery
Get access to Explority AI’s forecasts to outperform average preclinical success rates. Whether you’re expanding your R&D pipeline, evaluating a partnership, or simply have a question — we’d love to hear from you.