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1.
PLoS One ; 15(12): e0244301, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33338083

RESUMO

Adhesion and scarring after neural surgery are detrimental to nerve regeneration and functional recovery. Amniotic membranes have been used in tissue repair due to their immunogenicity and richness in cytokines. In this study, an electrospun polycaprolactone (PCL)-amnion nanofibrous membrane was prepared for the treatment of sciatic nerve compression in a rat model. The effects of the PCL-amnion nanofibrous membrane on the prevention of adhesion formation and nerve regeneration were evaluated using electrophysiology and histological analyses. Compared with the medical chitosan hydrogel dressing, the PCL-amnion nanofibrous membrane significantly reduced peripheral nerve adhesion and promoted the rapid recovery of nerve conduction. Moreover, the immunohistochemical analysis identified more Schwann cells and less pro-inflammatory M1 macrophages in the PCL-amnion group. Western blot and RT-PCR results showed that the expression levels of type-Ⅰ and Ⅲ collagen in the PCL-treated rats were half of those in the control group after 12 weeks, while the expression level of nerve growth factor was approximately 3.5 times that found in the rats treated with medical chitosan hydrogel. In summary, electrospun PCL-amnion nanofibrous membranes can effectively reduce adhesion after neural surgery and promote nerve repair and regeneration. The long-term retention in vivo and sustained release of cytokines make PCL-amnion a promising biomaterial for clinical application.


Assuntos
Regeneração Nervosa/efeitos dos fármacos , Poliésteres/farmacologia , Aderências Teciduais/prevenção & controle , Âmnio/patologia , Animais , Materiais Biocompatíveis , Quitosana/farmacologia , Colágeno/farmacologia , Modelos Animais de Doenças , Hidrogéis/farmacologia , Masculino , Nanofibras/química , Ratos , Ratos Sprague-Dawley , Células de Schwann/patologia , Nervo Isquiático/patologia , Neuropatia Ciática/fisiopatologia , Aderências Teciduais/tratamento farmacológico , Engenharia Tecidual/métodos , Tecidos Suporte
3.
Nucleic Acids Res ; 48(16): 8959-8976, 2020 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-32672815

RESUMO

Schwann cells are the nerve ensheathing cells of the peripheral nervous system. Absence, loss and malfunction of Schwann cells or their myelin sheaths lead to peripheral neuropathies such as Charcot-Marie-Tooth disease in humans. During Schwann cell development and myelination chromatin is dramatically modified. However, impact and functional relevance of these modifications are poorly understood. Here, we analyzed histone H2B monoubiquitination as one such chromatin modification by conditionally deleting the Rnf40 subunit of the responsible E3 ligase in mice. Rnf40-deficient Schwann cells were arrested immediately before myelination or generated abnormally thin, unstable myelin, resulting in a peripheral neuropathy characterized by hypomyelination and progressive axonal degeneration. By combining sequencing techniques with functional studies we show that H2B monoubiquitination does not influence global gene expression patterns, but instead ensures selective high expression of myelin and lipid biosynthesis genes and proper repression of immaturity genes. This requires the specific recruitment of the Rnf40-containing E3 ligase by Egr2, the central transcriptional regulator of peripheral myelination, to its target genes. Our study identifies histone ubiquitination as essential for Schwann cell myelination and unravels new disease-relevant links between chromatin modifications and transcription factors in the underlying regulatory network.


Assuntos
Proteína 2 de Resposta de Crescimento Precoce/fisiologia , Neuropatia Hereditária Motora e Sensorial/metabolismo , Histonas/metabolismo , Sistema Nervoso Periférico/metabolismo , Células de Schwann/metabolismo , Animais , Linhagem Celular Tumoral , Células HEK293 , Humanos , Camundongos , Camundongos Transgênicos , Sistema Nervoso Periférico/patologia , Ratos , Células de Schwann/patologia , Ubiquitina-Proteína Ligases/genética , Ubiquitinação
4.
Life Sci ; 256: 117959, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32531375

RESUMO

Resveratrol has the ability to promote functional recovery after sciatic nerve crush injury (SNCI), though the mechanism through which this occurs in not fully understood. Resveratrol can promote autophagy, a key process in Wallerian degeneration; thus, we hypothesized that resveratrol could promote recovery from SNCI by promoting Schwann cell autophagy and acceleration of Wallerian degeneration. Motor function recovery was assessed by calculating Sciatic Function Indexes (SFIs) at days 7, 14, 21, 28 post SNCI. Autophagy and myelin clearance were assessed by microtubule-associated protein light chain 3B (LC3B) and myelin protein zero (MPZ) immunofluorescence and Western blot analysis on the fourth day after SNCI. The autophagy of Schwann cells following resveratrol administration was quantified by immunofluorescence in RSC96 cells. Immunofluorescence and Transmission electron microscopy (TEM) were also used in Resveratrol treated sciatic nerve four days post-SNCI to find LC3B positive areas and typical double membrane structures represent for autophagy. The SNCI+resveratrol (crush+Res) groups recovered faster than the SNCI+vehicles (crush+V) group. On day four, almost all of the myelin had regenerated in the crush+Res rats, while the crush+V group's myelin remained intact and the expression levels of LC3-II/I was the highest. On day 28 post-injury, both the control and crush+Res groups' myelin neurofibers reached peak numbers as did the thickness of the myelin sheath. Both in vitro and in vivo immunofluorescence showed that LC3B was colocalized with Schwann cells. This is the first study to observe that resveratrol can promote recovery from SCNI by accelerating the myelin clearance process by promoting autophagy of Schwann cells.


Assuntos
Autofagia/efeitos dos fármacos , Lesões por Esmagamento/fisiopatologia , Compressão Nervosa , Recuperação de Função Fisiológica/efeitos dos fármacos , Resveratrol/farmacologia , Células de Schwann/patologia , Nervo Isquiático/patologia , Nervo Isquiático/fisiopatologia , Animais , Axônios/efeitos dos fármacos , Axônios/patologia , Lesões por Esmagamento/patologia , Masculino , Proteínas Associadas aos Microtúbulos/metabolismo , Atividade Motora/efeitos dos fármacos , Proteína P0 da Mielina/metabolismo , Bainha de Mielina/efeitos dos fármacos , Bainha de Mielina/metabolismo , Fibras Nervosas/efeitos dos fármacos , Fibras Nervosas/patologia , Regeneração Nervosa/efeitos dos fármacos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Células de Schwann/efeitos dos fármacos , Células de Schwann/metabolismo , Nervo Isquiático/efeitos dos fármacos
5.
J Neuropathol Exp Neurol ; 79(6): 647-651, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32388560

RESUMO

Localized hypertrophic neuropathy is a rare Schwann cell proliferation that usually affects single nerves from the extremities, and it is of unclear etiology in its pure form. RASopathies are a defined group of genetic diseases with overlapping clinical features, usually secondary to germline mutations in genes encoding either components or regulators of the RAS/MAPK pathway. Herein, we report an 11-year-old boy presenting with café au lait spots and right leg length discrepancy. A fascicular nerve biopsy of the tibial nerve demonstrated a Schwann cell proliferation with prominent onion-bulb formation, satisfying criteria for localized hypertrophic neuropathy. Molecular genetic analysis demonstrated identical KRAS mutations (c38_40dupGCG) in the peripheral nerve lesion and melanocytes from café au lait spots, but not in blood, supporting a diagnosis of a KRAS-mediated rasopathy with mosaicism. Immunohistochemical staining in the peripheral nerve lesion demonstrated strong pERK staining consistent with downstream MAPK pathway activation. This report suggests that at least a subset of localized hypertrophic neuropathies are bonafide, well-differentiated Schwann cell neoplasms developing through oncogenic RAS signaling, which provides new insights into the controversial entity historically known as localized hypertrophic neuropathy.


Assuntos
Doenças do Sistema Nervoso Periférico/patologia , Células de Schwann/patologia , Criança , Humanos , Hipertrofia/genética , Hipertrofia/patologia , Masculino , Mutação , Doenças do Sistema Nervoso Periférico/genética , Proteínas Proto-Oncogênicas p21(ras)/genética
6.
PLoS One ; 15(5): e0233623, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32469953

RESUMO

OBJECTIVES: To retrospectively determine the diagnostic ability of MRI in differentiating between intradural extramedullary spinal schwannomas and meningiomas. METHODS: A total of 199 patients with spinal intradural extramedullary tumors who underwent preoperative contrast-enhanced MRI between January 2012 and December 2018 were included in this study. Two radiologists independently analyzed the presence of cystic change, dural tail sign, and neural foraminal extension. Clinical and MRI features between the two groups were compared by univariable and multivariable analyses using logistic regression. Interobserver agreements were calculated using kappa statistics. RESULTS: Patients with schwannoma showed significantly higher frequency of cystic change (96% vs 24%, P < 0.001), neural foraminal extension (29% vs 3%, P = 0.001), and lumbar location (41% vs 5%, P = 0.008). Patients with meningioma showed significantly higher frequency of dural tail sign (64% vs 1%, P < 0.001), thoracic location (75% vs 31%, P = 0.007), older age (59.7 years vs 47.6 years, P < 0.001), higher female predominance (83% vs 50%, P < 0.001), and smaller size (19.8 cm vs 28.8 cm, P < 0.001). Multivariable analysis showed that cystic change (P < 0.001; odds ratio [OR], 0.02), dural tail sign (P < 0.001; OR, 36.23), age (P = 0.032; OR, 1.06), and lumbar location (P = 0.006; OR, 0.02) were independent factors. Interobserver agreements were almost perfect for all analyses. CONCLUSIONS: MRI features were useful in differentiating between intradural extramedullary schwannomas from meningiomas. The presence of cystic change and dural tail sign were independently significant discriminators.


Assuntos
Neoplasias Meníngeas/diagnóstico por imagem , Meningioma/diagnóstico por imagem , Neurilemoma/diagnóstico por imagem , Neoplasias da Coluna Vertebral/diagnóstico por imagem , Adulto , Idoso , Diagnóstico Diferencial , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Células de Schwann/patologia , Coluna Vertebral/diagnóstico por imagem , Coluna Vertebral/patologia
7.
Proc Natl Acad Sci U S A ; 117(16): 9032-9041, 2020 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-32253319

RESUMO

Lysosomal storage diseases (LSDs) are typically caused by a deficiency in a soluble acid hydrolase and are characterized by the accumulation of undegraded substrates in the lysosome. Determining the role of specific cell types in the pathogenesis of LSDs is a major challenge due to the secretion and subsequent uptake of lysosomal hydrolases by adjacent cells, often referred to as "cross-correction." Here we create and validate a conditional mouse model for cell-autonomous expression of galactocerebrosidase (GALC), the lysosomal enzyme deficient in Krabbe disease. We show that lysosomal membrane-tethered GALC (GALCLAMP1) retains enzyme activity, is able to cleave galactosylsphingosine, and is unable to cross-correct. Ubiquitous expression of GALCLAMP1 fully rescues the phenotype of the GALC-deficient mouse (Twitcher), and widespread deletion of GALCLAMP1 recapitulates the Twitcher phenotype. We demonstrate the utility of this model by deleting GALCLAMP1 specifically in myelinating Schwann cells in order to characterize the peripheral neuropathy seen in Krabbe disease.


Assuntos
Galactosilceramidase/metabolismo , Leucodistrofia de Células Globoides/patologia , Lisossomos/enzimologia , Proteínas Recombinantes de Fusão/metabolismo , Células de Schwann/patologia , Animais , Células Cultivadas , Modelos Animais de Doenças , Feminino , Fibroblastos , Galactosilceramidase/genética , Técnicas de Silenciamento de Genes , Humanos , Membranas Intracelulares/metabolismo , Leucodistrofia de Células Globoides/diagnóstico , Leucodistrofia de Células Globoides/genética , Glicoproteínas de Membrana Associadas ao Lisossomo/genética , Glicoproteínas de Membrana Associadas ao Lisossomo/metabolismo , Masculino , Camundongos , Camundongos Transgênicos , Cultura Primária de Células , Proteínas Recombinantes de Fusão/genética
8.
J Neuroimmunol ; 343: 577218, 2020 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-32251941

RESUMO

Data are sparse about mitochondrial damage in GBS and in its most frequently employed animal model, experimental autoimmune neuritis (EAN). We here characterized changes in mitochondrial content and morphology at different time points during EAN by use of ultrastructural imaging and immunofluorescent labelling. Histological examination revealed that demyelinated axons and their adjacent Schwann cells showed reduced mitochondrial content and remaining mitochondria appeared swollen with greater diameter in Schwann cells and unmyelinated axons. Our findings indicate that in EAN, particularly mitochondria in Schwann cells are damaged. Further studies are warranted to address whether these changes are amenable to novel, mitoprotective treatments.


Assuntos
Axônios/ultraestrutura , Mitocôndrias/ultraestrutura , Neurite Autoimune Experimental/patologia , Células de Schwann/ultraestrutura , Animais , Axônios/patologia , Feminino , Masculino , Microscopia Eletrônica de Transmissão , Mitocôndrias/patologia , Ratos , Ratos Endogâmicos Lew , Células de Schwann/patologia
9.
J Neuropathol Exp Neurol ; 79(4): 355-364, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32167544

RESUMO

Peripheral neuropathy is a common disorder with many possible etiologies including metabolic diseases, inflammatory conditions, infections, malignancy, inherited diseases, drugs, and toxins. In most instances, diagnosis and treatment plan can be established based on clinical presentation, family history, laboratory results, genetic testing, and electrophysiological studies. But in some situations, a peripheral nerve biopsy remains a valuable tool. This is especially true in patients with rapidly progressive disease, with atypical presentation or for whom other approaches fail to yield a definitive diagnosis. The pathologic examination starts with basic decisions about specimen triage. A few basic questions help to provide an initial framework for the assessment of a nerve biopsy-is the specimen adequate; are there inflammatory changes; are there vascular changes; is there amyloid; are there changes to axonal density and the Schwann cell-myelin-axon unit. In the appropriate context and with such an approach peripheral nerve biopsies can still represent a clinically helpful test.


Assuntos
Biópsia/métodos , Doenças do Sistema Nervoso Periférico/diagnóstico , Doenças do Sistema Nervoso Periférico/patologia , Amiloidose/diagnóstico , Amiloidose/patologia , Axônios/ultraestrutura , Humanos , Neuropatologia , Células de Schwann/patologia , Vasculite/diagnóstico , Vasculite/patologia
10.
Life Sci ; 248: 117459, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32092332

RESUMO

Diabetic peripheral neuropathy (DPN) is a common complication of diabetes mellitus that affects approximately half of patients with diabetes. Current treatment regimens cannot treat DPN effectively. Schwann cells (SCs) are very sensitive to glucose concentration and insulin, and closely associated with the occurrence and development of type 1 diabetic mellitus (T1DM) and DPN. Apoptosis of SCs is induced by hyperglycemia and is involved in the pathogenesis of DPN. This review considers the pathological processes of SCs apoptosis under high glucose, which include the following: oxidative stress, inflammatory reactions, endoplasmic reticulum stress, autophagy, nitrification and signaling pathways (PI3K/AKT, ERK, PERK/Nrf2, and Wnt/ß-catenin). The clarification of mechanisms underlying SCs apoptosis induced by high glucose will help us to understand and identify more effective strategies for the treatment of T1DM DPN.


Assuntos
Apoptose/efeitos dos fármacos , Neuropatias Diabéticas/genética , Glucose/farmacologia , Hiperglicemia/genética , Células de Schwann/efeitos dos fármacos , Animais , Apoptose/genética , Autofagia/efeitos dos fármacos , Autofagia/genética , Neuropatias Diabéticas/complicações , Neuropatias Diabéticas/metabolismo , Neuropatias Diabéticas/patologia , Estresse do Retículo Endoplasmático/efeitos dos fármacos , MAP Quinases Reguladas por Sinal Extracelular/genética , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Regulação da Expressão Gênica , Glucose/metabolismo , Humanos , Hiperglicemia/complicações , Hiperglicemia/metabolismo , Hiperglicemia/patologia , Insulina/metabolismo , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Células de Schwann/metabolismo , Células de Schwann/patologia , Transdução de Sinais , beta Catenina/genética , beta Catenina/metabolismo
11.
Infect Immun ; 88(4)2020 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-31964742

RESUMO

Neisseria meningitidis, a common cause of sepsis and bacterial meningitis, infects the meninges and central nervous system (CNS), primarily via paracellular traversal across the blood-brain barrier (BBB) or blood-cerebrospinal fluid barrier. N. meningitidis is often present asymptomatically in the nasopharynx, and the nerves extending between the nasal cavity and the brain constitute an alternative route by which the meningococci may reach the CNS. To date, the cellular mechanisms involved in nerve infection are not fully understood. Peripheral nerve glial cells are phagocytic and are capable of eliminating microorganisms, but some pathogens may be able to overcome this protection mechanism and instead infect the glia, causing cell death or pathology. Here, we show that N. meningitidis readily infects trigeminal Schwann cells (the glial cells of the trigeminal nerve) in vitro in both two-dimensional and three-dimensional cell cultures. Infection of trigeminal Schwann cells may be one mechanism by which N. meningitidis is able to invade the CNS. Infection of the cells led to multinucleation and the appearance of atypical nuclei, with the presence of horseshoe nuclei and the budding of nuclei increasing over time. Using sequential window acquisition of all theoretical mass spectra (SWATH-MS) proteomics followed by bioinformatics pathway analysis, we showed that N. meningitidis induced protein alterations in the glia that were associated with altered intercellular signaling, cell-cell interactions, and cellular movement. The analysis also suggested that the alterations in protein levels were consistent with changes occurring in cancer. Thus, infection of the trigeminal nerve by N. meningitidis may have ongoing adverse effects on the biology of Schwann cells, which may lead to pathology.


Assuntos
Interações Hospedeiro-Patógeno , Neisseria meningitidis/crescimento & desenvolvimento , Neisseria meningitidis/patogenicidade , Células de Schwann/microbiologia , Células de Schwann/patologia , Nervo Trigêmeo/citologia , Animais , Células Cultivadas , Camundongos Transgênicos , Proteoma/análise , Proteômica
12.
Phytomedicine ; 67: 153166, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31955133

RESUMO

BACKGROUND: Peripheral nerve injury can produce chronic and ultimately neuropathic pain. The chronic constriction injury (CCI) model has provided a deeper understanding of nociception and chronic pain. Loganin is a well-known herbal medicine with glucose-lowering action and neuroprotective activity. PURPOSE: This study investigated the molecular mechanisms by which loganin reduced CCI-induced neuropathic pain. METHODS: Sprague-Dawley rats were randomly divided into four groups: sham, sham+loganin, CCI and CCI+loganin. Loganin (1 or 5 mg/kg/day) was injected intraperitoneally once daily for 14 days, starting the day after CCI. For behavioral testing, mechanical and thermal responses were assessed before surgery and on d1, d3, d7 and d14 after surgery. Sciatic nerves (SNs) were collected to measure proinflammatory cytokines. Proximal and distal SNs were collected separately for Western blotting and immunofluorescence studies. RESULTS: Thermal hyperalgesia and mechanical allodynia were reduced in the loganin-treated group as compared to the CCI group. Loganin (5 mg/kg/day) prevented CCI from inducing proinflammatory cytokines (TNF-α, IL-1ß), inflammatory proteins (TNF-α, IL-1ß, pNFκB, pIκB/IκB, iNOS) and receptor (TNFR1, IL-1R), adaptor protein (TRAF2) of TNF-α, and Schwann cell demyelination and axonal damage. Loganin also blocked IκB phosphorylation (p-IκB). Double immunofluorescent staining further demonstrated that pNFκB/pIκB protein was reduced by loganin in Schwann cells on d7 after CCI. In the distal stumps of injured SN, Schwann cell demyelination was correlated with pain behaviors in CCI rats. CONCLUSION: Our findings indicate that loganin improves CCI-induced neuroinflammation and pain behavior by downregulating TNF-α/IL-1ß-dependent NF-κB activation.


Assuntos
Analgésicos não Entorpecentes/farmacologia , Iridoides/farmacologia , NF-kappa B/metabolismo , Neuralgia/tratamento farmacológico , Células de Schwann/efeitos dos fármacos , Animais , Dor Crônica/tratamento farmacológico , Dor Crônica/metabolismo , Dor Crônica/patologia , Constrição , Citocinas/metabolismo , Hiperalgesia/tratamento farmacológico , Hiperalgesia/metabolismo , Hiperalgesia/patologia , Interleucina-1beta/metabolismo , Masculino , Neuralgia/metabolismo , Neuralgia/patologia , Ratos Sprague-Dawley , Células de Schwann/metabolismo , Células de Schwann/patologia , Nervo Isquiático/efeitos dos fármacos , Nervo Isquiático/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
13.
Anat Sci Int ; 95(2): 230-239, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31848974

RESUMO

Peripheral neurodegenerative processes are essential for regenerating damaged peripheral nerves mechanically or genetically. Abnormal neurodegenerative processes induce peripheral neurodegenerative diseases via irreversible nerve damage. Carvacrol, a major component in Origanum vulgare, possesses various effects on organisms, such as antibiotic, anti-inflammatory and cytoprotective effects; although transient receptor potential (TRP) ankyrin 1 (TRPA1), TRP canonical 1 (TRPC1), TRP melastatin M7 (TRPM7), and TRP vanilloid 3 (TRPV3) are carvacrol-regulated TRPs, however, effect of carvacrol on the peripheral neurodegenerative process, and its underlying mechanism, remain unclear. Here, we investigated the specificity of carvacrol for TRPM7 in Schwann cells and the regulatory effect of carvacrol on TRPM7-dependent neurodegenerative processes. To construct peripheral nerve degeneration model, we used with a sciatic explant culture and sciatic nerve axotomy. Ex vivo, in vivo sciatic nerves were treated with carvacrol following an assessment of demyelination (ovoid fragmentation) and axonal degradation using morphometric indices. In these models, carvacrol effectively suppressed the morphometric indices, such as stripe, ovoid, myelin, and neurofilament indices during peripheral nerve degeneration. We found that carvacrol significantly inhibited upregulation of TRPM7 in Schwann cells. In this study, our results suggest that carvacrol effectively protects against the peripheral neurodegenerative process via TRPM7-dependent regulation in Schwann cells. Thus, pharmacological use of carvacrol could be helpful to protect against neurodegeneration that occurs with aging and peripheral neurodegenerative diseases, prophylactically.


Assuntos
Cimenos/farmacologia , Cimenos/uso terapêutico , Doenças Desmielinizantes/genética , Doenças Desmielinizantes/prevenção & controle , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/prevenção & controle , Fitoterapia , Proteínas Serina-Treonina Quinases/metabolismo , Células de Schwann/metabolismo , Canais de Cátion TRPM/metabolismo , Células Cultivadas , Cimenos/isolamento & purificação , Humanos , Origanum/química , Células de Schwann/patologia , Nervo Isquiático , Regulação para Cima/efeitos dos fármacos
14.
Cell Prolif ; 53(1): e12730, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31746040

RESUMO

OBJECTIVES: In peripheral neuropathy, the underlying mechanisms of nerve and muscle degeneration include chronic inflammation and oxidative stress in fibrotic tissues. (-)-Epigallocatechin gallate (EGCG) is a major, active component in green tea and may scavenge free radical oxygen and attenuate inflammation. Conservative treatments such as steroid injection only deal with early, asymptomatic, peripheral neuropathy. In contrast, neurolysis and nerve conduit implantation work effectively for treating advanced stages. MATERIALS AND METHODS: An EGCG-loaded polycaprolactone (PCL) porous scaffold was fabricated using an integrated moulding method. We evaluated proliferative, oxidative and inflammatory activity of rat Schwann cells (RSCs) and rat skeletal muscle cells (RSMCs) cultured on different scaffolds in vitro. In a rat radiation injury model, we assessed the morphological, electrophysiological and functional performance of regenerated sciatic nerves and gastrocnemius muscles, as well as oxidative stress and inflammation state. RESULTS: RSCs and RSMCs exhibited higher proliferative, anti-oxidant and anti-inflammatory states in an EGCG/PCL scaffold. In vivo studies showed improved nerve and muscle recovery in the EGCG/PCL group, with increased nerve myelination and muscle fibre proliferation and reduced macrophage infiltration, lipid peroxidation, inflammation and oxidative stress indicators. CONCLUSIONS: The EGCG-modified PCL porous nerve scaffold alleviates cellular oxidative stress and repairs peripheral nerve and muscle structure in rats. It attenuates oxidative stress and inflammation in vivo and may provide further insights into peripheral nerve repair in the future.


Assuntos
Catequina/análogos & derivados , Regeneração Nervosa/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Estresse Oxidativo , Doenças do Sistema Nervoso Periférico/tratamento farmacológico , Poliésteres , Lesões Experimentais por Radiação/tratamento farmacológico , Células de Schwann/metabolismo , Nervo Isquiático/fisiologia , Tecidos Suporte/química , Animais , Catequina/química , Catequina/farmacologia , Linhagem Celular , Músculo Esquelético/inervação , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Doenças do Sistema Nervoso Periférico/metabolismo , Doenças do Sistema Nervoso Periférico/patologia , Poliésteres/química , Poliésteres/farmacologia , Porosidade , Lesões Experimentais por Radiação/metabolismo , Lesões Experimentais por Radiação/patologia , Ratos , Células de Schwann/patologia , Nervo Isquiático/lesões , Nervo Isquiático/patologia
15.
Nucleic Acids Res ; 48(1): 130-140, 2020 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-31713617

RESUMO

Charcot-Marie-Tooth 1A (CMT1A) is the most common inherited neuropathy without a known therapy, which is caused by a 1.4 Mb duplication on human chromosome 17, which includes the gene encoding the peripheral myelin protein of 22 kDa (PMP22). Overexpressed PMP22 protein from its gene duplication is thought to cause demyelination and subsequently axonal degeneration in the peripheral nervous system (PNS). Here, we targeted TATA-box of human PMP22 promoter to normalize overexpressed PMP22 level in C22 mice, a mouse model of CMT1A harboring multiple copies of human PMP22. Direct local intraneural delivery of CRISPR/Cas9 designed to target TATA-box of PMP22 before the onset of disease, downregulates gene expression of PMP22 and preserves both myelin and axons. Notably, the same approach was effective in partial rescue of demyelination even after the onset of disease. Collectively, our data present a proof-of-concept that CRISPR/Cas9-mediated targeting of TATA-box can be utilized to treat CMT1A.


Assuntos
Doença de Charcot-Marie-Tooth/terapia , Terapia de Alvo Molecular/métodos , Proteínas da Mielina/genética , Bainha de Mielina/metabolismo , Células de Schwann/metabolismo , TATA Box , Animais , Axônios , Sistemas CRISPR-Cas , Doença de Charcot-Marie-Tooth/genética , Doença de Charcot-Marie-Tooth/metabolismo , Doença de Charcot-Marie-Tooth/patologia , Duplicação Cromossômica , Cromossomos Humanos Par 17 , Modelos Animais de Doenças , Edição de Genes/métodos , Humanos , Injeções , Camundongos , Proteínas da Mielina/metabolismo , Bainha de Mielina/patologia , Cultura Primária de Células , Regiões Promotoras Genéticas , Células de Schwann/patologia , Nervo Isquiático/metabolismo , Nervo Isquiático/patologia
16.
Neurosci Res ; 150: 29-36, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30731109

RESUMO

After sciatic nerve injury, Schwann cells in the distal segments of injury site undergo apoptosis and meanwhile proliferation. Although apoptosis-induced proliferation (AiP) has been characterized in various models, whether the proliferation of Schwann cells in the distal segments is triggered by apoptosis remains unelucidated. In this study, we used small interfering RNA to knock down the expression of TNFR1 and TNFR2 in primarily cultured Schwann cells, respectively and observed its effects on apoptosis and proliferation. The downregulation of TNFR1 or TNFR2 resulted in a remarkable decrease of cell viability and dramatically increased the apoptosis of Schwann cells. In contrast, the cell apoptosis induced by the knockdown of TNFR2, but not TNFR1, promoted the Schwann cell proliferation. Together, these observations indicated that Schwann cells can undergo AiP, and TNFR2 knockdown triggers the process. Additionally, we established the sciatic nerve injury model on TNF-α knock-out (KO) mice, and found that the Schwann cells of KO mice occurred significantly less apoptosis and proliferation than that of wild-type mice in the distal segments, which indicated TNF-α and its receptors were essential in the massive apoptosis and the apoptosis-induced proliferation of Schwann cells after sciatic nerve injury. The finding of AiP in Schwann cells may be beneficial to develop new approaches to promote axon regeneration and thereby improve the functional recovery after peripheral nerve injury.


Assuntos
Receptores Tipo II do Fator de Necrose Tumoral/genética , Receptores Tipo II do Fator de Necrose Tumoral/metabolismo , Células de Schwann/citologia , Células de Schwann/metabolismo , Animais , Apoptose/fisiologia , Axônios/metabolismo , Proliferação de Células/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Regeneração Nervosa/fisiologia , Traumatismos dos Nervos Periféricos/metabolismo , Cultura Primária de Células , Ratos , Ratos Sprague-Dawley , Células de Schwann/patologia , Nervo Isquiático/metabolismo , Fator de Necrose Tumoral alfa/deficiência , Fator de Necrose Tumoral alfa/metabolismo
17.
Diagn Cytopathol ; 48(3): 228-233, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31743600

RESUMO

Pseudoglandular schwannoma (PGS) is a rare morphological variant of benign schwannoma. PGS is quite distinct from the somewhat better characterized glandular schwannoma variant. PGS is characterized by the presence of gland-like structures lined with pseudocolumnar or cuboidal-like neoplastic Schwann cells lining variably sized cystic space cells. Herein, we describe a rare case of PGS in a 17-year-old adolescent boy with a neck mass 8.5 cm in diameter present for 2 years with a recent increase in size. Fine-needle aspiration (FNA) demonstrated abundant rhabdoid-like cuboidal cells, plasmacytoid cells, binucleation, clusters of round to oval cells with scant cytoplasm, and a lack of stromal cells with spindle or oval nuclei. These findings were challenging and were reminiscent of alveolar rhabdomyosarcoma on FNA. Magnetic resonance imaging was also suggestive of malignancy. However, the histologic picture and the immunohistochemical analysis of the resected mass were consisted with PGS. The numerous rhabdoid-like cuboidal neoplastic Schwann cells with a plasmacytoid appearance, paving cystic spaces, and the lack of blunt-ended proliferating stromal cells on smears mimicked alveolar rhabdomyosarcoma on FNA. To our knowledge, cytological features of PGS have not been previously reported. This is the first published report of an unusual PGS case located in the neck region causing a diagnostic dilemma on cytology.


Assuntos
Neoplasias de Cabeça e Pescoço , Neurilemoma , Rabdomiossarcoma Alveolar , Células de Schwann , Adolescente , Biópsia por Agulha Fina , Diagnóstico Diferencial , Neoplasias de Cabeça e Pescoço/diagnóstico , Neoplasias de Cabeça e Pescoço/metabolismo , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Masculino , Neurilemoma/diagnóstico , Neurilemoma/metabolismo , Neurilemoma/patologia , Rabdomiossarcoma Alveolar/diagnóstico , Rabdomiossarcoma Alveolar/metabolismo , Rabdomiossarcoma Alveolar/patologia , Células de Schwann/metabolismo , Células de Schwann/patologia
18.
Cell Mol Life Sci ; 77(9): 1847-1858, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31375869

RESUMO

Devil facial tumour disease (DFTD) comprises two genetically distinct transmissible cancers (DFT1 and DFT2) endangering the survival of the Tasmanian devil (Sarcophilus harrisii) in the wild. DFT1 first arose from a cell of the Schwann cell lineage; however, the tissue-of-origin of the recently discovered DFT2 cancer is unknown. In this study, we compared the transcriptome and proteome of DFT2 tumours to DFT1 and normal Tasmanian devil tissues to determine the tissue-of-origin of the DFT2 cancer. Our findings demonstrate that DFT2 expresses a range of Schwann cell markers and exhibits expression patterns consistent with a similar origin to the DFT1 cancer. Furthermore, DFT2 cells express genes associated with the repair response to peripheral nerve damage. These findings suggest that devils may be predisposed to transmissible cancers of Schwann cell origin. The combined effect of factors such as frequent nerve damage from biting, Schwann cell plasticity and low genetic diversity may allow these cancers to develop on rare occasions. The emergence of two independent transmissible cancers from the same tissue in the Tasmanian devil presents an unprecedented opportunity to gain insight into cancer development, evolution and immune evasion in mammalian species.


Assuntos
Biomarcadores Tumorais/metabolismo , Neoplasias Faciais/veterinária , Marsupiais/fisiologia , Proteoma/análise , Células de Schwann/patologia , Transcriptoma , Animais , Biomarcadores Tumorais/genética , Neoplasias Faciais/genética , Neoplasias Faciais/metabolismo , Neoplasias Faciais/patologia , Humanos , Células de Schwann/metabolismo
19.
J Biol Chem ; 295(29): 9948-9958, 2020 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-33685622

RESUMO

Neurofibromatosis type 1 (NF1) is a common cancer predisposition syndrome caused by mutations in the NF1 tumor suppressor gene. NF1 encodes neurofibromin, a GTPase-activating protein for RAS proto-oncogene GTPase (RAS). Plexiform neurofibromas are a hallmark of NF1 and result from loss of heterozygosity of NF1 in Schwann cells, leading to constitutively activated p21RAS. Given the inability to target p21RAS directly, here we performed an shRNA library screen of all human kinases and Rho-GTPases in a patient-derived NF1-/- Schwann cell line to identify novel therapeutic targets to disrupt PN formation and progression. Rho family members, including Rac family small GTPase 1 (RAC1), were identified as candidates. Corroborating these findings, we observed that shRNA-mediated knockdown of RAC1 reduces cell proliferation and phosphorylation of extracellular signal-regulated kinase (ERK) in NF1-/- Schwann cells. Genetically engineered Nf1flox/flox;PostnCre+ mice, which develop multiple PNs, also exhibited increased RAC1-GTP and phospho-ERK levels compared with Nf1flox/flox;PostnCre- littermates. Notably, mice in which both Nf1 and Rac1 loci were disrupted (Nf1flox/floxRac1flox/flox;PostnCre+) were completely free of tumors and had normal phospho-ERK activity compared with Nf1flox/flox;PostnCre+ mice. We conclude that the RAC1-GTPase is a key downstream node of RAS and that genetic disruption of the Rac1 allele completely prevents PN tumor formation in vivo in mice.


Assuntos
Deleção de Genes , Neurofibroma Plexiforme/prevenção & controle , Neurofibromatoses/fisiopatologia , Neurofibromina 1/metabolismo , RNA Interferente Pequeno/genética , Células de Schwann/metabolismo , Proteínas rac1 de Ligação ao GTP/antagonistas & inibidores , Animais , Proliferação de Células , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Ensaios de Triagem em Larga Escala , Humanos , Camundongos , Neurofibroma Plexiforme/genética , Neurofibroma Plexiforme/patologia , Neurofibromina 1/genética , Fosforilação , Células de Schwann/patologia , Proteínas rac1 de Ligação ao GTP/genética
20.
Mol Brain ; 12(1): 101, 2019 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-31791378

RESUMO

Schwann cells experience de-differentiation, proliferation, migration, re-differentiation and myelination, and participate in the repair and regeneration of injured peripheral nerves. Our previous sequencing analysis suggested that the gene expression level of matrix metalloproteinase 7 (MMP7), a Schwann cell-secreted proteolytic enzyme, was robustly elevated in rat sciatic nerve segments after nerve injury. However, the biological roles of MMP7 are poorly understood. Here, we exposed primary cultured Schwann cells with MMP7 recombinant protein and transfected siRNA against MMP7 into Schwann cells to examine the effect of exogenous and endogenous MMP7. Meanwhile, the effects of MMP7 in nerve regeneration after sciatic nerve crush in vivo were observed. Furthermore, RNA sequencing and bioinformatic analysis of Schwann cells were conducted to show the molecular mechanism behind the phenomenon. In vitro studies showed that MMP7 significantly elevated the migration rate of Schwann cells but did not affect the proliferation rate of Schwann cells. In vivo studies demonstrated that increased level of MMP7 contributed to Schwann cell migration and myelin sheaths formation after peripheral nerve injury. MMP7-mediated genetic changes were revealed by sequencing and bioinformatic analysis. Taken together, our current study demonstrated the promoting effect of MMP7 on Schwann cell migration and peripheral nerve regeneration, benefited the understanding of cellular and molecular mechanisms underlying peripheral nerve injury, and thus might facilitate the treatment of peripheral nerve regeneration in clinic.


Assuntos
Movimento Celular , Metaloproteinase 7 da Matriz/metabolismo , Bainha de Mielina/metabolismo , Células de Schwann/enzimologia , Células de Schwann/patologia , Nervo Isquiático/lesões , Nervo Isquiático/patologia , Animais , Axônios/metabolismo , Proliferação de Células , Regulação da Expressão Gênica , Masculino , Bainha de Mielina/ultraestrutura , Ratos Sprague-Dawley , Células de Schwann/ultraestrutura , Nervo Isquiático/ultraestrutura
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