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1.
Toxicol Lett ; 320: 95-102, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31760062

RESUMO

Exposure to organic solvent in industry, including n-hexane is correlated with central-peripheral axonopathy, which is mediated by its active metabolite, 2,5-hexanedione (HD). However, the underlying mechanism is still largely unknown. Recently identified microRNAs (miRNAs) may play important roles in toxicant exposure and in the process of toxicant-induced neuropathys. To examine the role of miRNAs in HD-induced toxicity, neuropathic animal model was successfully built. miRNA microarray analysis revealed 105 differentially expressed miRNAs after HD exposure. Bioinformatics analysis showed that "Axon" and "Neurotrophin Signaling Pathway" was the top significant GO term and pathway, respectively. 7 miRNAs both related to "Axon" and "Neurotrophin Signaling Pathway" were screened out and further confirmed by Real-Time PCR. Correspondingly, the deregulation expression levels of proteins of four target genes (GSK3ß, Map3k1, BDNF and MAP1B) were further confirmed via western blot, verifying the results of gene target analysis. Taken together, our results showed that the axon-related miRNAs to be associated with MAP1B or neurotrophin signal pathways changed in nerve tissues following HD exposure. These miRNAs may play important roles in HD-induced neurotoxicity.


Assuntos
Axônios/efeitos dos fármacos , Hexanonas/toxicidade , MicroRNAs/metabolismo , Síndromes Neurotóxicas/etiologia , Nervo Isquiático/efeitos dos fármacos , Solventes/toxicidade , Medula Espinal/efeitos dos fármacos , Animais , Axônios/metabolismo , Fator Neurotrófico Derivado do Encéfalo/genética , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Bases de Dados Genéticas , Regulação da Expressão Gênica , Glicogênio Sintase Quinase 3 beta/genética , Glicogênio Sintase Quinase 3 beta/metabolismo , MAP Quinase Quinase Quinase 1/genética , MAP Quinase Quinase Quinase 1/metabolismo , Masculino , MicroRNAs/genética , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Síndromes Neurotóxicas/genética , Síndromes Neurotóxicas/metabolismo , Ratos Sprague-Dawley , Nervo Isquiático/metabolismo , Transdução de Sinais , Medula Espinal/metabolismo , Transcriptoma
2.
Muscle Nerve ; 60(5): 613-620, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31397908

RESUMO

INTRODUCTION: The objective of this study is to assess the efficacy of local tacrolimus (FK506) delivery to improve outcomes in the setting of nerve transection injury. METHODS: FK506 embedded poly(lactide-co-caprolactone) films capable of extended, localized release of FK506 were developed. FK506 rate of release testing and bioactivity assay was performed. Mouse sciatic nerve transection and direct repair model was used to evaluate the effect extended, local delivery of FK506 had on nerve regeneration outcomes. RESULTS: Linear release of FK506 was observed for 30 days and released FK506 matched control levels of neurite extension in the dorsal root ganglion assay. Groups treated with local FK506 had greater gastrocnemius muscle weight, foot electromyogram, and number of axons distal of the repair site than non-FK506 groups. DISCUSSION: Results of this study indicate that extended, localized delivery of FK506 to nerve injuries can improve nerve regeneration outcomes in a mouse sciatic nerve transection and repair.


Assuntos
Imunossupressores/farmacologia , Denervação Muscular , Músculo Esquelético/efeitos dos fármacos , Regeneração Nervosa/efeitos dos fármacos , Nervo Isquiático/lesões , Tacrolimo/farmacologia , Animais , Axônios/efeitos dos fármacos , Axônios/patologia , Preparações de Ação Retardada , Eletromiografia , Gânglios Espinais/efeitos dos fármacos , Imunossupressores/administração & dosagem , Camundongos , Músculo Esquelético/patologia , Neuritos/efeitos dos fármacos , Neuritos/patologia , Procedimentos Neurocirúrgicos , Tamanho do Órgão , Traumatismos dos Nervos Periféricos , Poliésteres , Nervo Isquiático/efeitos dos fármacos , Nervo Isquiático/patologia , Nervo Isquiático/cirurgia , Tacrolimo/administração & dosagem
3.
Nat Commun ; 10(1): 3530, 2019 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-31387998

RESUMO

Microtubules are a vital component of the cell's cytoskeleton and their organization is crucial for healthy cell functioning. The use of label-free SH imaging of microtubules remains limited, as sensitive detection is required and the true molecular origin and main determinants required to generate SH from microtubules are not fully understood. Using advanced correlative imaging techniques, we identified the determinants of the microtubule-dependent SH signal. Microtubule polarity, number and organization determine SH signal intensity in biological samples. At the molecular level, we show that the GTP-bound tubulin dimer conformation is fundamental for microtubules to generate detectable SH signals. We show that SH imaging can be used to study the effects of microtubule-targeting drugs and proteins and to detect changes in tubulin conformations during neuronal maturation. Our data provide a means to interpret and use SH imaging to monitor changes in the microtubule network in a label-free manner.


Assuntos
Microscopia Intravital/métodos , Microtúbulos/ultraestrutura , Imagem Molecular/métodos , Microscopia de Geração do Segundo Harmônico , Animais , Axônios/efeitos dos fármacos , Axônios/metabolismo , Células Cultivadas , Colchicina/farmacologia , Estudos de Viabilidade , Guanosina Trifosfato/metabolismo , Camundongos , Microscopia Eletrônica , Microtúbulos/efeitos dos fármacos , Microtúbulos/metabolismo , Neurogênese , Cultura Primária de Células , Tubulina (Proteína)/metabolismo , Tubulina (Proteína)/ultraestrutura
4.
Neurochem Res ; 44(9): 2215-2229, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31422522

RESUMO

The ability to regrow their axons after an injury is a hallmark of neurons in peripheral nervous system which distinguish them from central nervous system neurons. This ability is influenced by their intrinsic capacity to regrow and by the extracellular environment which needs to be supportive of regrowth. CXCL1 [Chemokine (C-X-C motif) Ligand 1] and CXCL2 [Chemokine (C-X-C motif) Ligand 2] are two low-molecular-weight chemokines which can influence neuronal proliferation, differentiation and neurogenesis, but which are also upregulated by injury or inflammation. In this study we investigated the effects of long-term incubation (24, 48 and 72 h) with different concentrations of CXCL1 (0.4, 4 or 40 nM) or CXCL2 (0.36, 3.6 or 36 nM) on the axon outgrowth of adult rat dorsal root ganglia neurons in culture. The results showed that both chemokines significantly inhibited the axon outgrowth, with large and medium NF200 (NeuroFilament 200) (+) dorsal root ganglia neurons affected quicker, compared to small IB4 (Isolectin B4) (+) dorsal root ganglia neurons which were affected after longer exposure. Blocking CXCR2 (C-X-C motif chemokine receptor 2) which mediates the effects of CXCL1 and CXCL2 prevented these effects, suggesting that CXCR2 may represent a new therapeutic target for promoting the axon outgrowth after a peripheral nerve injury.


Assuntos
Axônios/efeitos dos fármacos , Quimiocina CXCL1/farmacologia , Quimiocina CXCL2/farmacologia , Gânglios Espinais/citologia , Crescimento Neuronal/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Animais , Masculino , Ratos Wistar
5.
Biomed Res Int ; 2019: 9628065, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31467921

RESUMO

The reparative process following spinal cord injury (SCI) is extremely complicated. Cells in the microenvironment express multiple inhibitory factors that affect axonal regeneration over a prolonged period of time. The axon growth inhibitory factor glycogen synthase kinase-3 (GSK-3) is an important factor during these processes. TDZD-8 (4-benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione) is the most effective and specific non-ATP-competitive inhibitor of GSK-3. Here, we show that administering TDZD-8 after SCI was associated with significantly inhibited neuronal apoptosis, upregulated GAP-43 expression, increased density of cortical spinal tract fibers around areas of injury, and increased Basso, Beattie, and Bresnahan (BBB) scores in the lower limbs. These findings support the notion that GSK-3 inhibitors promote neuronal cell regeneration and lower limb functional recovery.


Assuntos
Quinase 3 da Glicogênio Sintase/antagonistas & inibidores , Regeneração Nervosa/efeitos dos fármacos , Traumatismos da Medula Espinal/tratamento farmacológico , Tiadiazóis/farmacologia , Animais , Apoptose/efeitos dos fármacos , Axônios/efeitos dos fármacos , Modelos Animais de Doenças , Proteína GAP-43/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Quinase 3 da Glicogênio Sintase/genética , Humanos , Atividade Motora/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Ratos , Recuperação de Função Fisiológica/efeitos dos fármacos , Medula Espinal/fisiopatologia , Traumatismos da Medula Espinal/fisiopatologia
6.
J Mater Sci Mater Med ; 30(7): 82, 2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-31273463

RESUMO

Axon regeneration and functional recovery after peripheral nerve injury remains a clinical challenge. Injury leads to axonal disintegration after which Schwann cells (SCs) and macrophages re-engage in the process of regeneration. At present, biomaterials are regarded as the most promising way to repair peripheral nerve damage. As a natural material, keratin has a wide range of sources and has good biocompatibility and biodegradability. Here, a keratin was extracted from human hair by reducing method and a keratin sponge with porous structure was obtained by further processing. The results suggested that keratin can promote cell adhesion, proliferation, migration as well as the secretion of neurotrophic factors by SCs and the regulation of the expression of macrophage inflammatory cytokines in vitro. We report for the first time that human hair keratin can promote the extension of axon in DRG neurons. The motor deficits caused by a sciatic nerve crush injury were alleviated by keratin sponge dressing in vivo. Thus, keratin has been identified as a valuable biomaterial that can enhance peripheral nerve regeneration.


Assuntos
Cabelo/química , Queratinas Específicas do Cabelo/farmacologia , Regeneração Nervosa/efeitos dos fármacos , Nervos Periféricos/efeitos dos fármacos , Nervo Isquiático/lesões , Animais , Axônios/efeitos dos fármacos , Materiais Biocompatíveis , Adesão Celular , Linhagem Celular , Movimento Celular , Proliferação de Células , Citocinas/metabolismo , Humanos , Inflamação , Macrófagos/efeitos dos fármacos , Masculino , Camundongos , Neurônios/metabolismo , Células RAW 264.7 , Ratos , Ratos Sprague-Dawley , Células de Schwann/efeitos dos fármacos , Cicatrização
7.
Turk Neurosurg ; 29(5): 743-749, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31353438

RESUMO

AIM: To investigate the effects of systemic application of Theranekron on peripheral nerve healing after compression type peripheral nerve injury. MATERIAL AND METHODS: Twenty-one female Wistar albino rats were randomly divided into 3 groups (n=7): Control (C), injury (I), and Theranekron (T). The right sciatic nerves of rats in the I and T groups were compressed via an aneurysm clip for 5 minutes and 0.3 ml Theranekron D6 was applied via subcutaneous administration once a week in the T group for a total period of four weeks. Nerve conduction velocity and proximal and distal latency of the rats were measured at the end of day 30. The right sciatic nerves of the rats were then removed and myelin damage grading, axon counting, fibrosis assessment, caspase-3, and NF-kB immunochemical staining were performed. The data were analysed statistically and a p value of less than 0.05 was considered to be significant. RESULTS: Axonal degeneration, vacuolization and myelin destruction were found to be markedly greater in group T. Fibrosis and caspase-3 immunoreactivity were less intense in group T. There was a statistically significant difference in the electrophysiological results of groups I and T. However, there were no statistically significant differences in axon number and NF-kB immunochemical evaluation of groups I and T. CONCLUSION: The findings of this study show that Theranekron decreases axonal and myelin damage after sciatic nerve injury and that this neuroprotective effect of Theranekron can be attributed to its anti-inflammatory effect on pro-inflammatory cytokine levels.


Assuntos
Regeneração Nervosa/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Traumatismos dos Nervos Periféricos , Venenos de Aranha/farmacologia , Animais , Anti-Inflamatórios/farmacologia , Axônios/efeitos dos fármacos , Feminino , Extratos Vegetais/farmacologia , Ratos , Ratos Wistar , Nervo Isquiático/lesões
8.
Neurochem Res ; 44(8): 1964-1976, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31218567

RESUMO

Schwann cells are essential glial cells in the peripheral nervous system (PNS), and dysfunction of Schwann cells can induce various peripheral neurodegenerative diseases. Oxidative stress has been implicated as a causative factor in degenerative nerve diseases; however, there no effective molecules are available to inhibit nerve degeneration in peripheral neurodegenerative diseases. Ethyl pyruvate (EP) is a candidate regulator of oxidative stress, targeting Schwann cells during peripheral nerve degeneration. Here, we investigated the effects of EP on axonal degradation, demyelination, transcriptional regulation, and macrophage recruitment during Wallerian degeneration of the sciatic nerve, ex vivo and in vivo. EP prevented the expression of neuronal nitric oxide synthase (NOS1), but not that of inducible nitric oxide synthase (NOS2), during Wallerian degeneration. These results suggest that effect of EP on Schwann cells may protect against peripheral nerve degeneration through its NOS1-specific regulation.


Assuntos
Inibidores Enzimáticos/uso terapêutico , Fármacos Neuroprotetores/uso terapêutico , Óxido Nítrico Sintase Tipo I/antagonistas & inibidores , Piruvatos/uso terapêutico , Células de Schwann/efeitos dos fármacos , Degeneração Walleriana/prevenção & controle , Animais , Axônios/efeitos dos fármacos , Doenças Desmielinizantes/patologia , Doenças Desmielinizantes/prevenção & controle , Macrófagos/efeitos dos fármacos , Masculino , Camundongos Endogâmicos C57BL , Bainha de Mielina/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-jun/metabolismo , Nervo Isquiático/efeitos dos fármacos , Nervo Isquiático/patologia , Degeneração Walleriana/patologia
9.
Psychopharmacology (Berl) ; 236(9): 2761-2771, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31165206

RESUMO

RATIONALE: As the hub of memory and space, hippocampus is very sensitive to a wide variety of injuries and is one of the earliest brain structures to develop neurodegenerative changes in AD. Previous research has showed a protective effect of potassium 2-(l-hydroxypentyl)-benzoate (PHPB) on cognitive deficits in animal models of AD. However, it is unclear whether this protective effect is associated with hippocampal alterations. OBJECTIVES: The present study was conducted to evaluate the protective effect of PHPB on hippocampal neurodegenerative changes in middle-aged APP/PS1 mice. METHODS: Ten-month-old male APP/PS1 transgenic mice and age-matched wild-type mice were randomly divided into three groups. PHPB-treated APP/PS1 group received 30 mg/kg PHPB by oral gavage once daily for 12 weeks. Wild-type group and APP/PS1 group received the same volume of water alone. Twelve weeks later, mice (13-month-old) were tested for in vivo 1H-MRS examination and then sacrificed for subsequent biochemical and pathological examinations using transmission electron microscopy, Golgi staining, immunohistochemistry, and western blotting. RESULTS: We found that PHPB treatment significantly improved the micromorphology of hippocampal neurons and subcellular organelles, ameliorated synapse loss and presynaptic axonal dystrophy, increased hippocampal dendritic spine density and dendritic complexity, enhanced the expression of hippocampal synapse-associated proteins, and improved hippocampal metabolism in middle-aged APP/PS1 mice. CONCLUSIONS: Our study showed for the first time the protective effect of PHPB on hippocampal neurons, synapses, and dystrophic axons in APP/PS1 mice, which to some extent revealed the possible mechanism for its ability to improve cognition in animal models of AD.


Assuntos
Precursor de Proteína beta-Amiloide/metabolismo , Axônios/metabolismo , Hipocampo/metabolismo , Fármacos Neuroprotetores/administração & dosagem , Presenilina-1/metabolismo , Sinapses/metabolismo , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Precursor de Proteína beta-Amiloide/genética , Animais , Axônios/efeitos dos fármacos , Axônios/patologia , Benzoatos/administração & dosagem , Cognição/efeitos dos fármacos , Cognição/fisiologia , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Masculino , Memória/efeitos dos fármacos , Camundongos , Camundongos Transgênicos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Pentanóis/administração & dosagem , Potássio/administração & dosagem , Presenilina-1/genética , Distribuição Aleatória , Sinapses/genética , Sinapses/patologia , Resultado do Tratamento
10.
Environ Health Perspect ; 127(6): 67003, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31166131

RESUMO

BACKGROUND: The pyrethroid deltamethrin (DM) is broadly used for insect control. Although DM hyperexcites neuronal networks by delaying inactivation of axonal voltage-dependent [Formula: see text] channels, this mechanism is unlikely to mediate neurotoxicity at lower exposure levels during critical perinatal periods in mammals. OBJECTIVES: We aimed to identify mechanisms by which acute and subchronic DM altered axonal and dendritic growth, patterns of synchronous [Formula: see text] oscillations (SCOs), and electrical spike activity (ESA) functions critical to neuronal network formation. METHODS: Measurements of SCOs using [Formula: see text] imaging, ESA using microelectrode array (MEA) technology, and dendritic complexity using Sholl analysis were performed in primary murine cortical neurons from wild-type (WT) and/or ryanodine receptor 1 ([Formula: see text]) mice between 5 and 14 d in vitro (DIV). [Formula: see text] binding analysis and a single-channel voltage clamp were utilized to measure engagement of RyRs as a direct target of DM. RESULTS: Neuronal networks responded to DM ([Formula: see text]) as early as 5 DIV, reducing SCO amplitude and depressing ESA and burst frequencies by 60-70%. DM ([Formula: see text]) enhanced axonal growth in a nonmonotonic manner. [Formula: see text] enhanced dendritic complexity. DM stabilized channel open states of RyR1, RyR2, and cortical preparations expressing all three isoforms. DM ([Formula: see text]) altered gating kinetics of RyR1 channels, increasing mean open time, decreasing mean closed time, and thereby enhancing overall open probability. SCO patterns from cortical networks expressing [Formula: see text] were more responsive to DM than WT. [Formula: see text] neurons showed inherently longer axonal lengths than WT neurons and maintained less length-promoting responses to nanomolar DM. CONCLUSIONS: Our findings suggested that RyRs were sensitive molecular targets of DM with functional consequences likely relevant for mediating abnormal neuronal network connectivity in vitro. https://doi.org/10.1289/EHP4583.


Assuntos
Neurônios/efeitos dos fármacos , Nitrilos/toxicidade , Piretrinas/toxicidade , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Animais , Axônios/efeitos dos fármacos , Cálcio/metabolismo , Células Cultivadas , Feminino , Inseticidas/toxicidade , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Plasticidade Neuronal/efeitos dos fármacos , Canal de Liberação de Cálcio do Receptor de Rianodina/genética
11.
J Pharmacol Toxicol Methods ; 98: 106585, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31112751

RESUMO

RAR-related orphan receptor-γt (RORγt) directs differentiation of proinflammatory T helper 17 cells and is a potential therapeutic target for chronic autoimmune and inflammatory diseases including multiple sclerosis. In this study, zebrafish at days post fertilization treated with ethidium bromide (EB) at a concentration of 75 µM for 72 h were determined as the optimum conditions for the demyelination model development. Zebrafish motility was recorded automatically using a video-track motion detector and quantitative myelin assay was measured by FluoroMyelin staining. A well-known remyelination agent thyroxine (T4) was tested to confirm whether EB-induced motility and myelin damage could be rescued. Two RORγt lead inhibitors GSK805 and SR1001 were assessed for their therapeutic effects on remyelination, axon regeneration, motor neuron promotion and anti-inflammation. T4 significantly improved EB-induced motility dysfunction and myelin damage and promoted myelin basic protein (MBP) regeneration in the demyelinated zebrafish. GSK805 and SR1001 enhanced remyelination in a dose-dependent manner and promoted MBP regeneration. Both GSK805 and SR1001 markedly recovered EB-induced axon and motor neuron damage, and exhibited significantly inhibitory effects of neutrophil infiltration and macrophage recruitment. These results indicate that EB treatment can induce zebrafish demyelination; and the zebrafish demyelination model in combination with quantitative motility and myelin assays is a predictive, reproducible and relatively high throughput screening for rapidly in vivo identification of remyelination compounds and RORγt inhibitors.


Assuntos
Doenças Desmielinizantes/tratamento farmacológico , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/antagonistas & inibidores , Remielinização/efeitos dos fármacos , Peixe-Zebra/fisiologia , Animais , Animais Geneticamente Modificados , Axônios/efeitos dos fármacos , Modelos Animais de Doenças , Etídio/farmacologia , Proteína Básica da Mielina , Bainha de Mielina/efeitos dos fármacos , Regeneração Nervosa/efeitos dos fármacos
12.
Neurochem Res ; 44(7): 1726-1735, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31087207

RESUMO

Tacrolimus, a calcineurin (CaN) inhibitor, has been used for treatment of refractory allergic ocular disease, although its role in optic nerve degeneration remains to be elucidated. In this study, we investigated whether tacrolimus modulates tumor necrosis factor (TNF)-mediated axonal degeneration and whether it alters nuclear factor of activated T cells (NFATc), a downstream effector of CaN signaling. Immunoblot analysis showed no significant difference in CaNAα protein levels in optic nerve on day 3, 7, or 14 after TNF injection compared with PBS injection. However, a significant increase in NFATc1 protein level was observed in optic nerve 7 days after TNF injection. This increase was negated by simultaneous administration of tacrolimus. Administration of tacrolimus alone did not change the NFATc1 protein level in comparison to that observed after PBS injection. A significant increase in TNF protein level was observed in optic nerve 14 days after TNF injection and this increase was prevented by tacrolimus. Immunohistochemical analysis showed the immunoreactivity of NFATc1 to be increased in optic nerve after TNF injection. This increased immunoreactivity was colocalized with glial fibrillary acidic protein and was suppressed by tacrolimus. Treatment of tacrolimus significantly ameliorated the TNF-mediated axonal loss. These results suggest that tacrolimus is neuroprotective against axon loss in TNF-induced optic neuropathy and that the effect arises from suppression of the CaN/NFATc1 pathway.


Assuntos
Axônios/efeitos dos fármacos , Degeneração Neural/prevenção & controle , Fármacos Neuroprotetores/uso terapêutico , Doenças do Nervo Óptico/prevenção & controle , Tacrolimo/uso terapêutico , Fatores de Transcrição/antagonistas & inibidores , Animais , Axônios/patologia , Inibidores de Calcineurina/uso terapêutico , Masculino , Degeneração Neural/induzido quimicamente , Degeneração Neural/patologia , Nervo Óptico/patologia , Doenças do Nervo Óptico/induzido quimicamente , Doenças do Nervo Óptico/patologia , Ratos Wistar , Transdução de Sinais/efeitos dos fármacos , Fator de Necrose Tumoral alfa/metabolismo
13.
Chem Biol Interact ; 308: 70-79, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31100276

RESUMO

Tri-ortho-cresyl phosphate (TOCP) is a typical organophosphorus compound that can cause organophosphate-induced delayed neuropathy (OPIDN), which is pathologically characterized by axonal degeneration. Nowadays, mitochondrial dysfunction is regarded as a potential mechanism contributing to OPIDN progress. Mitophagy, a selective type of autophagy, is required to segregate damaged mitochondria from healthy mitochondrial networks and deliver them to lysosome for degradation. This research was designed to investigate the role of mitophagy in axon degeneration following TOCP administration in an in vitro model. Differentiated neuro2a (N2a) cells were divided into four groups and treated with 0, 5, 10, and 20 µM TOCP for 24 h, respectively. The critical proteins in PINK1-Parkin-dependent mitophagy including LC3, P62, PINK1, Parkin, mitochondrial proteins, and autophagic receptors were detected by immunoblotting and immunofluorescence. After TOCP treatment, increased level of ROS in N2a cells revealed a significant mitochondria damage. Meanwhile, it was observed that much more PINK1, Parkin, and LC3-II were translocated to the mitochondria. Furthermore, immunofluorescence analysis demonstrated that the co-localization of Parkin and LC3 was significantly increased. These results suggested that PINK1-Parkin dependent mitophagy pathway in N2a cells was activated by TOCP treatment. In addition, P62, a major autophagic receptor, was markedly accumulated on the mitochondria, which indicated that P62 might play a critical role in facilitating mitophagy under TOCP-induced axonal degeneration. Taken together, our results suggest that TOCP exposure resulted in the activation of PINK1-Parkin-dependent mitophagy in N2a cells. Mitophagy may act as a positively reactive mode in eliminating dysfunctional mitochondria and therefore protect neurons against TOCP neurotoxicity.


Assuntos
/efeitos dos fármacos , Proteínas Quinases/metabolismo , Tritolil Fosfatos/farmacologia , Ubiquitina-Proteína Ligases/metabolismo , Animais , Axônios/efeitos dos fármacos , Axônios/metabolismo , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Camundongos , Proteínas Associadas aos Microtúbulos/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Proteína Sequestossoma-1/metabolismo
14.
PLoS One ; 14(5): e0209733, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31048836

RESUMO

We have previously shown that a single application of the growth factors ciliary neurotrophic factor (CNTF) or fibroblast growth factor 2 (FGF-2) to the crushed optic nerve of the frog, Rana pipiens, increases the numbers and elongation rate of regenerating retinal ganglion cell axons. Here we investigate the effects of these factors on the numbers and types of macrophages that invade the regeneration zone. In control PBS-treated nerves, many macrophages are present 100 µm distal to the crush site at 1 week after injury; their numbers halve by 2 weeks. A single application of CNTF at the time of injury triples the numbers of macrophages at 1 week, with this increase compared to control being maintained at 2 weeks. Application of FGF-2 is equally effective at 1 week, but the macrophage numbers have fallen to control levels at 2 weeks. Immunostaining with a pan-macrophage marker, ED1, and a marker for M2-like macrophages, Arg-1, showed that the proportion of the putative M2 phenotype remained at approximately 80% with all treatments. Electron microscopy of the macrophages at 1 week shows strong phagocytic activity with all treatments, with many vacuoles containing axon fragments and membrane debris. At 2 weeks with PBS or FGF-2 treatment the remaining macrophages are less phagocytically active, containing mainly lipid inclusions. With CNTF treatment, at 2 weeks many of the more numerous macrophages are still phagocytosing axonal debris, although they also contain lipid inclusions. We conclude that the increase in macrophage influx seen after growth factor application is beneficial for the regenerating axons, probably due to more extensive removal of degenerating distal axons, but also perhaps to secretion of growth-promoting substances.


Assuntos
Fator Neurotrófico Ciliar/farmacologia , Fator Neurotrófico Ciliar/uso terapêutico , Fator 2 de Crescimento de Fibroblastos/farmacologia , Fator 2 de Crescimento de Fibroblastos/uso terapêutico , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Traumatismos do Nervo Óptico/tratamento farmacológico , Traumatismos do Nervo Óptico/metabolismo , Animais , Axônios/efeitos dos fármacos , Axônios/metabolismo , Axônios/ultraestrutura , Imuno-Histoquímica , Microscopia Eletrônica , Rana pipiens , Vacúolos/efeitos dos fármacos , Vacúolos/metabolismo , Vacúolos/ultraestrutura
15.
Anat Sci Int ; 94(4): 285-294, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30949912

RESUMO

Oxidative stress contributes to the progression of neurodegenerative diseases of the central and peripheral nervous systems, including Alzheimer's disease, Parkinson's disease, stroke, and diabetic neuropathy. Despite the greater capability of peripheral nerves to regenerate compared with those in the brain or spinal cord, chronic oxidative stress leads to irreversible neurodegeneration in peripheral nerves. Thus, many efforts have been made to defend against irreversible peripheral nerve degeneration and oxidative stress. Numerous phytochemicals have been revealed as antioxidants which neutralize free radicals and reduce peripheral neurocellular damage. Among them, polyphenols alleviate neurodegeneration by interacting with reactive oxygen species. Apigenin is a polyphenol found in plant-derived foods, including parsley, thyme, celery, and chamomile tea. Apigenin has been reported to exert antioxidative effects by scavenging free radicals. In particular, apigenin has a neuroprotective effect against oxidative stress in neurological disorders, such as cerebral ischemia. However, to date, no studies have shown an association of the inhibitory effect of apigenin with peripheral nerve degeneration. In this work, we showed that apigenin has a neuroprotective effect against peripheral nerve degeneration according to four key phenotypes: axonal degradation, myelin fragmentation, trans-dedifferentiation, and proliferation of Schwann cells via Krox20- and extracellular signal-regulated kinase-independent processes. Thus, apigenin could be a good candidate to treat peripheral neurodegenerative diseases.


Assuntos
Apigenina/farmacologia , Depuradores de Radicais Livres/farmacologia , Doenças Neurodegenerativas/tratamento farmacológico , Fármacos Neuroprotetores/farmacologia , Doenças do Sistema Nervoso Periférico/tratamento farmacológico , Animais , Apigenina/uso terapêutico , Axônios/efeitos dos fármacos , Axônios/patologia , Desdiferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Proteína 2 de Resposta de Crescimento Precoce/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Depuradores de Radicais Livres/uso terapêutico , Humanos , Masculino , Camundongos , Doenças Neurodegenerativas/patologia , Fármacos Neuroprotetores/uso terapêutico , Estresse Oxidativo/efeitos dos fármacos , Doenças do Sistema Nervoso Periférico/patologia , Espécies Reativas de Oxigênio/metabolismo , Células de Schwann/efeitos dos fármacos , Células de Schwann/patologia , Nervo Isquiático/patologia
16.
J Mol Histol ; 50(3): 263-271, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31016544

RESUMO

Oxidative stress with mitochondrial defects has a central role in the development and deterioration of Multiple sclerosis (MS). According to new findings of the effects of metformin on mitochondrial function, has attracted a lot of attention. Furthermore, it is suggested that metformin exerts its beneficial influence through AMP-activated protein kinase (AMPK) pathway. In the current study, we investigated the possible protective effects of metformin on oxidative stress and mitochondrial function by activating the AMPK pathway in the cuprizone-induced demyelination. Mice were fed with cuprizone for 6 weeks. Animals simultaneously received metformin. After sacrificing animals, myelinations, and gliosis, changes in transcription factor and biochemical analysis were assessed. Transmission electron microscopy and luxol fast blue staining revealed that the myelinated axons within corpus callosum of cuprizone-induced demyelination animals increased after administration of metformin. Metformin also upregulated the expression of mitochondrial biogenesis genes. Furthermore, the biochemical analysis demonstrated that metformin ameliorated the oxidative stress induced by cuprizone. Immunohistochemistry analysis showed that astrogliosis and microgliosis were decreased after metformin administration while it enhanced the number of oligodendrocytes. Our data implicated that metformin exerts its therapeutic effects on MS by AMPK signaling improved mitochondrial homeostasis and protected oligodendrocytes.


Assuntos
Metformina/administração & dosagem , Mitocôndrias/efeitos dos fármacos , Esclerose Múltipla/tratamento farmacológico , Proteínas Quinases/genética , Animais , Axônios/efeitos dos fármacos , Axônios/patologia , Cuprizona/toxicidade , Doenças Desmielinizantes/induzido quimicamente , Doenças Desmielinizantes/tratamento farmacológico , Doenças Desmielinizantes/patologia , Modelos Animais de Doenças , Hemostasia/efeitos dos fármacos , Hemostasia/genética , Humanos , Camundongos , Mitocôndrias/genética , Esclerose Múltipla/induzido quimicamente , Esclerose Múltipla/patologia , Oligodendroglia/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos
17.
Phys Rev E ; 99(2-1): 022408, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30934335

RESUMO

Geometrical cues play an essential role in neuronal growth. Here, we quantify axonal growth on surfaces with controlled geometries and report a general stochastic approach that quantitatively describes the motion of growth cones. We show that axons display a strong directional alignment on micropatterned surfaces when the periodicity of the patterns matches the dimension of the growth cone. The growth cone dynamics on surfaces with uniform geometry is described by a linear Langevin equation with both deterministic and stochastic contributions. In contrast, axonal growth on surfaces with periodic patterns is characterized by a system of two generalized Langevin equations with both linear and quadratic velocity dependence and stochastic noise. We combine experimental data with theoretical analysis to measure the key parameters of the growth cone motion: angular distributions, correlation functions, diffusion coefficients, characteristics speeds, and damping coefficients. We demonstrate that axonal dynamics displays a crossover from an Ornstein-Uhlenbeck process to a nonlinear stochastic regime when the geometrical periodicity of the pattern approaches the linear dimension of the growth cone. Growth alignment is determined by surface geometry, which is fully quantified by the deterministic part of the Langevin equation. These results provide insight into the role of curvature sensing proteins and their interactions with geometrical cues.


Assuntos
Neurônios/citologia , Animais , Axônios/efeitos dos fármacos , Axônios/metabolismo , Proliferação de Células/efeitos dos fármacos , Dimetilpolisiloxanos/farmacologia , Modelos Neurológicos , Neurônios/efeitos dos fármacos , Nylons/farmacologia , Ratos
18.
Mol Neurobiol ; 56(10): 7144-7158, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30989631

RESUMO

Current strategies to enhance regeneration of peripheral neurons involve broad activation of sensory, autonomic, and motor axons. Peripheral neuron regeneration is limited in persons with damage or disease of peripheral axons. Here, we provide evidence that subtoxic activation of TRPV1 channels in sensory neurons is associated with activation of growth and subtle changes in skin reinnervation. We identify a bidirectional, dose-related impact of capsaicin, a TRPV1 agonist, on sensory neurons and their axons with rises in their outgrowth plasticity at low doses and toxic neurodegeneration at high doses. Moreover, its impact on growth added to that of preconditioning. Neither outcome was observed in TRPV1 null neurons. We confirmed that low dose activation was associated with rises in neuronal calcium, as well as rises in TRPV1 mRNA transcripts. In mice with a sciatic nerve crush followed by a single application of capsaicin directly to the injury site, there was no impact on motor or myelinated axon recovery but there was evidence of better recovery of thermal sensation toward baseline with hyperalgesia. Moreover, skin reinnervation by epidermal axons approached contralateral levels. TRPV1 null mice displayed loss of thermal sensation during later recovery. In sensory axons innervating the pinna of the ear, local capsaicin rendered early axon loss followed by later hyperinnervation. Taken together, TRPV1 activation alters the regenerative behavior of adult neurons and their axons both in vitro and during epidermal reinnervation in vivo. The findings identify a selective manipulation that augments cutaneous innervation by thermosensitive axons.


Assuntos
Axônios/metabolismo , Ativação do Canal Iônico , Células Receptoras Sensoriais/metabolismo , Canais de Cátion TRPV/metabolismo , Animais , Axônios/efeitos dos fármacos , Cálcio/metabolismo , Sinalização do Cálcio/efeitos dos fármacos , Capsaicina/farmacologia , Citosol/metabolismo , Epiderme/efeitos dos fármacos , Epiderme/inervação , Ativação do Canal Iônico/efeitos dos fármacos , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurônios Motores/efeitos dos fármacos , Neurônios Motores/metabolismo , Regeneração Nervosa/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos Sprague-Dawley , Remielinização/efeitos dos fármacos , Células Receptoras Sensoriais/efeitos dos fármacos , Temperatura Ambiente
19.
Nat Neurosci ; 22(5): 700-708, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31011227

RESUMO

Williams syndrome (WS), caused by a heterozygous microdeletion on chromosome 7q11.23, is a neurodevelopmental disorder characterized by hypersociability and neurocognitive abnormalities. Of the deleted genes, general transcription factor IIi (Gtf2i) has been linked to hypersociability in WS, although the underlying mechanisms are poorly understood. We show that selective deletion of Gtf2i in the excitatory neurons of the forebrain caused neuroanatomical defects, fine motor deficits, increased sociability and anxiety. Unexpectedly, 70% of the genes with significantly decreased messenger RNA levels in the mutant mouse cortex are involved in myelination, and mutant mice had reduced mature oligodendrocyte cell numbers, reduced myelin thickness and impaired axonal conductivity. Restoring myelination properties with clemastine or increasing axonal conductivity rescued the behavioral deficits. The frontal cortex from patients with WS similarly showed reduced myelin thickness, mature oligodendrocyte cell numbers and mRNA levels of myelination-related genes. Our study provides molecular and cellular evidence for myelination deficits in WS linked to neuronal deletion of Gtf2i.


Assuntos
Comportamento Animal , Bainha de Mielina/metabolismo , Neurônios/metabolismo , Prosencéfalo/metabolismo , Remielinização/efeitos dos fármacos , Fatores de Transcrição TFII/genética , Síndrome de Williams/genética , Animais , Axônios/efeitos dos fármacos , Clemastina/administração & dosagem , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Destreza Motora , Bainha de Mielina/ultraestrutura , Comportamento Social , Transcriptoma
20.
Mol Pain ; 15: 1744806919838191, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30813850

RESUMO

The formation of neuromas involves expansion of the cellular components of peripheral nerves. The onset of these disorganized tumors involves activation of sensory nerves and neuroinflammation. Particularly problematic in neuroma is arborization of axons leading to extreme, neuropathic pain. The most common sites for neuroma are the ends of transected nerves following injury; however, this rodent model does not reliably result in neuroma formation. In this study, we established a rodent model of neuroma in which the sciatic nerve was loosely ligated with two chromic gut sutures. This model formed neuromas reliably (∼95%), presumably through activation of the neural inflammatory cascade. Resulting neuromas had a disorganized structure and a significant number of replicating cells. Quantification of changes in perineurial and Schwann cells showed a significant increase in these populations. Immunohistochemical analysis showed the presence of ß-tubulin 3 in the rapidly expanding nerve and a decrease in neurofilament heavy chain compared to the normal nerve, suggesting the axons forming a disorganized structure. Measurement of the permeability of the blood-nerve barrier shows that it opened almost immediately and remained open as long as 10 days. Studies using an antagonist of the ß3-adrenergic receptor (L-748,337) or cromolyn showed a significant reduction in tumor size and cell expansion as determined by flow cytometry, with an improvement in the animal's gait detected using a Catwalk system. Previous studies in our laboratory have shown that heterotopic ossification is also a result of the activation of neuroinflammation. Since heterotopic ossification and neuroma often occur together in amputees, they were induced in the same limbs of the study animals. More heterotopic bone was formed in animals with neuromas as compared to those without. These data collectively suggest that perturbation of early neuroinflammation with compounds such as L-748,337 and cromolyn may reduce formation of neuromas.


Assuntos
Neuroma/tratamento farmacológico , Neuroma/metabolismo , Nervo Isquiático/efeitos dos fármacos , Agonistas de Receptores Adrenérgicos beta 3/uso terapêutico , Animais , Axônios/efeitos dos fármacos , Axônios/metabolismo , Proteína Morfogenética Óssea 2/genética , Proteína Morfogenética Óssea 2/metabolismo , Linhagem Celular , Citometria de Fluxo , Imuno-Histoquímica , Camundongos , Ratos , Receptores Adrenérgicos beta 3/metabolismo , Células de Schwann/efeitos dos fármacos , Células de Schwann/metabolismo , Nervo Isquiático/metabolismo , Tubulina (Proteína)/metabolismo
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