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1.
Croat Med J ; 61(4): 354-365, 2020 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-32881434

RESUMO

AIM: To analyze axon morphology on rapid Golgi impregnated pyramidal neurons in the dorsolateral prefrontal cortex in schizophrenia. METHODS: Postmortem brain tissue from five subjects diagnosed with schizophrenia and five control subjects without neuropathological findings was processed with the rapid Golgi method. Layer III and layer V pyramidal neurons from Brodmann area 9 were chosen in each brain for reconstruction with Neurolucida software. The axons and cell bodies of 136 neurons from subjects with schizophrenia and of 165 neurons from control subjects were traced. The data obtained by quantitative analysis were compared between the schizophrenia and control group with the t test. RESULTS: Axon impregnation length was consistently greater in the schizophrenia group. The axon main trunk length was significantly greater in the schizophrenia than in the control group (93.7 ± 36.6 µm vs 49.8 ± 9.9 µm, P = 0.032). Furthermore, in the schizophrenia group more axons had visibly stained collaterals (14.7% vs 5.5%). CONCLUSION: Axon rapid Golgi impregnation stops at the beginning of the myelin sheath. The increased axonal staining in the schizophrenia group could, therefore, be explained by reduced axon myelination. Such a decrease in axon myelination is in line with both the disconnection hypothesis and the two-hit model of schizophrenia as a neurodevelopmental disease. Our results support that the cortical circuitry disorganization in schizophrenia might be caused by functional alterations of two major classes of principal neurons due to altered oligodendrocyte development.


Assuntos
Axônios/patologia , Córtex Pré-Frontal/patologia , Células Piramidais/patologia , Esquizofrenia/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Complexo de Golgi/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Coloração e Rotulagem/métodos
2.
Nat Commun ; 11(1): 4029, 2020 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-32788597

RESUMO

In autosomal dominant optic atrophy (ADOA), caused by mutations in the mitochondrial cristae biogenesis and fusion protein optic atrophy 1 (Opa1), retinal ganglion cell (RGC) dysfunction and visual loss occur by unknown mechanisms. Here, we show a role for autophagy in ADOA pathogenesis. In RGCs expressing mutated Opa1, active 5' AMP-activated protein kinase (AMPK) and its autophagy effector ULK1 accumulate at axonal hillocks. This AMPK activation triggers localized hillock autophagosome accumulation and mitophagy, ultimately resulting in reduced axonal mitochondrial content that is restored by genetic inhibition of AMPK and autophagy. In C. elegans, deletion of AMPK or of key autophagy and mitophagy genes normalizes the axonal mitochondrial content that is reduced upon mitochondrial dysfunction. In conditional, RGC specific Opa1-deficient mice, depletion of the essential autophagy gene Atg7 normalizes the excess autophagy and corrects the visual defects caused by Opa1 ablation. Thus, our data identify AMPK and autophagy as targetable components of ADOA pathogenesis.


Assuntos
Autofagia , Atrofia Óptica Autossômica Dominante/complicações , Transtornos da Visão/complicações , Adenilato Quinase/metabolismo , Animais , Autofagia/genética , Axônios/patologia , Caenorhabditis elegans/metabolismo , Modelos Animais de Doenças , Ativação Enzimática , GTP Fosfo-Hidrolases/genética , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitocôndrias/metabolismo , Mitofagia , Mutação/genética , Fosforilação , Células Ganglionares da Retina/patologia
3.
Proc Natl Acad Sci U S A ; 117(27): 15955-15966, 2020 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-32554499

RESUMO

Axon regeneration is regulated by a neuron-intrinsic transcriptional program that is suppressed during development but that can be reactivated following peripheral nerve injury. Here we identify Prom1, which encodes the stem cell marker prominin-1, as a regulator of the axon regeneration program. Prom1 expression is developmentally down-regulated, and the genetic deletion of Prom1 in mice inhibits axon regeneration in dorsal root ganglion (DRG) cultures and in the sciatic nerve, revealing the neuronal role of Prom1 in injury-induced regeneration. Elevating prominin-1 levels in cultured DRG neurons or in mice via adeno-associated virus-mediated gene delivery enhances axon regeneration in vitro and in vivo, allowing outgrowth on an inhibitory substrate. Prom1 overexpression induces the consistent down-regulation of cholesterol metabolism-associated genes and a reduction in cellular cholesterol levels in a Smad pathway-dependent manner, which promotes axonal regrowth. We find that prominin-1 interacts with the type I TGF-ß receptor ALK4, and that they synergistically induce phosphorylation of Smad2. These results suggest that Prom1 and cholesterol metabolism pathways are possible therapeutic targets for the promotion of neural recovery after injury.


Assuntos
Antígeno AC133/metabolismo , Axônios/metabolismo , Colesterol/metabolismo , Regeneração Nervosa/fisiologia , Transdução de Sinais , Células-Tronco/metabolismo , Antígeno AC133/genética , Receptores de Ativinas Tipo I , Animais , Axônios/patologia , Colesterol/genética , Regulação para Baixo , Gânglios Espinais/metabolismo , Deleção de Genes , Regulação da Expressão Gênica , Camundongos , Camundongos Knockout , Neurônios/metabolismo , Traumatismos dos Nervos Periféricos/metabolismo , Receptor do Fator de Crescimento Transformador beta Tipo I/metabolismo , Nervo Isquiático
4.
PLoS One ; 15(6): e0235110, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32584865

RESUMO

Programmed axonal degeneration, also known as Wallerian degeneration, occurs in immune-mediated central nervous system (CNS) inflammatory disorders such as multiple sclerosis and the animal model experimental allergic encephalomyelitis (EAE). Sterile alpha and TIR domain containing protein 1 (SARM1) functions to promote programmed axonal degeneration. To test the hypothesis that loss of SARM1 will reduce axonal degeneration in immune-mediated CNS inflammatory disorders, the course and pathology of EAE was compared in Sarm1 knockout mice and wild type littermates. The clinical course of EAE was similar in Sarm1 knockout and wild type. Analysis of EAE in mice expressing neuronal yellow fluorescent protein (YFP) showed significantly less axonal degeneration in Sarm1 knockout mice compared to wild type littermates at 14 days post-induction of EAE. At 21 days post-induction, however, difference in axonal degeneration was not significant. At 42 days post-induction, Sarm1 knockout mice were indistinguishable from wild type with respect to markers of axonal injury, and were similar with respect to axonal density in the lumbar cords. There was no significant change in peripheral immune activation or CNS inflammatory cell infiltration associated with EAE in Sarm1 knockout mice. In conclusion, Sarm1 deletion delayed axonal degeneration early in the course of CNS inflammation, but did not confer long-term protection from axonal degeneration in an animal model of immune-mediated CNS inflammation.


Assuntos
Proteínas do Domínio Armadillo , Axônios , Proteínas do Citoesqueleto , Encefalomielite Autoimune Experimental , Técnicas de Inativação de Genes , Medula Espinal , Animais , Proteínas do Domínio Armadillo/genética , Proteínas do Domínio Armadillo/metabolismo , Axônios/metabolismo , Axônios/patologia , Proteínas do Citoesqueleto/genética , Proteínas do Citoesqueleto/metabolismo , Encefalomielite Autoimune Experimental/genética , Encefalomielite Autoimune Experimental/metabolismo , Encefalomielite Autoimune Experimental/patologia , Encefalomielite Autoimune Experimental/prevenção & controle , Camundongos , Camundongos Knockout , Medula Espinal/metabolismo , Medula Espinal/patologia , Fatores de Tempo
5.
PLoS One ; 15(6): e0234519, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32530970

RESUMO

Axonal damage leads to the release of neurofilament light chain (NFL), which enters the CSF or blood. In this work, an assay kit for plasma NFL utilizing immunomagnetic reduction (IMR) was developed. Antibodies against NFL were immobilized on magnetic nanoparticles to develop an IMR NFL kit. The preclinical properties, such as the standard curve, limit of detection (LoD), and dynamic range, were characterized. Thirty-one normal controls (NC), fifty-two patients with Parkinson's disease (PD) or PD dementia (PDD) and thirty-one patients with Alzheimer's disease (AD) were enrolled in the study evaluating the plasma NFL assay using an IMR kit. T-tests and receiver operating characteristic (ROC) curve analysis were performed to investigate the capability for discrimination among the clinical groups according to plasma NFL levels. The LoD of the NFL assay using the IMR kit was found to be 0.18 fg/ml. The dynamic range of the NFL assay reached 1000 pg/ml. The NC group showed a plasma NFL level of 7.70 ± 4.00 pg/ml, which is significantly lower than that of the PD/PDD (15.85 ± 7.82 pg/ml, p < 0.001) and AD (19.24 ± 8.99 pg/ml, p < 0.001) groups. A significant difference in plasma NFL levels was determined between the PD and AD groups (p < 0.01). Through ROC curve analysis, the cut-off value of the plasma NFL concentration for differentiating NCs from dementia patients (AD and PD/PDD) was found to be 12.71 pg/ml, with a clinical sensitivity and specificity of 73.5% and 90.3%, respectively. The AUC was 0.868. Furthermore, the cut-off value of the plasma NFL concentration for discriminating AD from PD/PDD was found to be 18.02 pg/ml, with a clinical sensitivity and specificity of 61.3% and 65.4%, respectively. The AUC was 0.630. An ultrasensitive assay for measuring plasma NFL utilizing IMR technology was developed. Clear differences in plasma NFL concentrations were observed among NCs and PD and AD patients. These results imply that the determination of plasma NFL is promising not only for screening dementia but also for differential diagnosis.


Assuntos
Peptídeos beta-Amiloides/sangue , Biomarcadores/sangue , Proteínas de Neurofilamentos/sangue , Proteínas tau/sangue , Doença de Alzheimer/sangue , Doença de Alzheimer/patologia , Axônios/metabolismo , Axônios/patologia , Disfunção Cognitiva/sangue , Disfunção Cognitiva/genética , Disfunção Cognitiva/patologia , Feminino , Humanos , Separação Imunomagnética , Filamentos Intermediários/genética , Filamentos Intermediários/patologia , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/sangue , Doença de Parkinson/genética , Doença de Parkinson/patologia
6.
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
7.
Neurology ; 95(9): e1144-e1152, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32586900

RESUMO

OBJECTIVE: To quantify the associations of peripapillary retinal nerve fiber layer (pRNFL) thickness and macular ganglion cell layer (mGCL) volume with cognitive functioning and to investigate how demographic and vascular health factors affect these associations in a population-based sample of adults. METHODS: The sample included the first 3,000 participants (age range 30-95 years) of the Rhineland Study (recruited from March 2016 to December 2018) who underwent spectral-domain optical coherence tomography and cognitive assessment at 1 of 2 identical study centers in Bonn, Germany. We used multiple linear regression models to examine the relationships between retinal layer measurements and cognitive functioning after adjustment for confounders, and we examined the moderating effects of demographic and vascular health factors. RESULTS: The analytical sample included 2,483 participants who were 54.3 years old (SD 13.8 years) on average. After full adjustment, each 1-SD decrease in mGCL volume was associated with a greater decrease in global function than that of pRNFL thickness (ß = -0.048 [95% confidence interval (CI) -0.077 to -0.018] vs ß = -0.021 [95% CI -0.049 to 0.007]). These relationships increased in strength with advancing age, were stronger in participants with hypertension, and were reversed in current smokers relative to nonsmokers. CONCLUSIONS: mGCL volume is more strongly related to adult cognitive functioning than pRNFL thickness, making it a better potential biomarker of neurodegeneration. Age and vascular health factors play important roles in determining the strength and direction of this association.


Assuntos
Axônios/patologia , Cognição , Função Executiva , Inteligência , Memória Episódica , Memória de Curto Prazo , Disco Óptico/patologia , Células Ganglionares da Retina/patologia , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Hipertensão , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Retina/diagnóstico por imagem , Retina/patologia , Risco , Fumar , Tomografia de Coerência Óptica
8.
J Virol ; 94(14)2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32404525

RESUMO

Mouse hepatitis virus (MHV) is a murine betacoronavirus (m-CoV) that causes a wide range of diseases in mice and rats, including hepatitis, enteritis, respiratory diseases, and encephalomyelitis in the central nervous system (CNS). MHV infection in mice provides an efficient cause-effect experimental model to understand the mechanisms of direct virus-induced neural-cell damage leading to demyelination and axonal loss, which are pathological features of multiple sclerosis (MS), the most common disabling neurological disease in young adults. Infiltration of T lymphocytes, activation of microglia, and their interplay are the primary pathophysiological events leading to disruption of the myelin sheath in MS. However, there is emerging evidence supporting gray matter involvement and degeneration in MS. The investigation of T cell function in the pathogenesis of deep gray matter damage is necessary. Here, we employed RSA59 (an isogenic recombinant strain of MHV-A59)-induced experimental neuroinflammation model to compare the disease in CD4-/- mice with that in CD4+/+ mice at days 5, 10, 15, and 30 postinfection (p.i.). Viral titer estimation, nucleocapsid gene amplification, and viral antinucleocapsid staining confirmed enhanced replication of the virions in the absence of functional CD4+ T cells in the brain. Histopathological analyses showed elevated susceptibility of CD4-/- mice to axonal degeneration in the CNS, with augmented progression of acute poliomyelitis and dorsal root ganglionic inflammation rarely observed in CD4+/+ mice. Depletion of CD4+ T cells showed unique pathological bulbar vacuolation in the brain parenchyma of infected mice with persistent CD11b+ microglia/macrophages in the inflamed regions on day 30 p.i. In summary, the current study suggests that CD4+ T cells are critical for controlling acute-stage poliomyelitis (gray matter inflammation), chronic axonal degeneration, and inflammatory demyelination due to loss of protective antiviral host immunity.IMPORTANCE The current trend in CNS disease biology is to attempt to understand the neural-cell-immune interaction to investigate the underlying mechanism of neuroinflammation, rather than focusing on peripheral immune activation. Most studies in MS are targeted toward understanding the involvement of CNS white matter. However, the importance of gray matter damage has become critical in understanding the long-term progressive neurological disorder. Our study highlights the importance of CD4+ T cells in safeguarding neurons against axonal blebbing and poliomyelitis from murine betacoronavirus-induced neuroinflammation. Current knowledge of the mechanisms that lead to gray matter damage in MS is limited, because the most widely used animal model, experimental autoimmune encephalomyelitis (EAE), does not present this aspect of the disease. Our results, therefore, add to the existing limited knowledge in the field. We also show that the microglia, though important for the initiation of neuroinflammation, cannot establish a protective host immune response without the help of CD4+ T cells.


Assuntos
Axônios/imunologia , Axônios/metabolismo , Antígenos CD4/deficiência , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/virologia , Vírus da Hepatite Murina/fisiologia , Poliomielite/etiologia , Animais , Axônios/patologia , Encéfalo/imunologia , Encéfalo/metabolismo , Encéfalo/patologia , Contagem de Linfócito CD4 , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Infecções por Coronavirus/patologia , Citocinas/metabolismo , Modelos Animais de Doenças , Suscetibilidade a Doenças/imunologia , Gânglios Espinais/imunologia , Gânglios Espinais/metabolismo , Gânglios Espinais/patologia , Imuno-Histoquímica , Mediadores da Inflamação/metabolismo , Camundongos
9.
Nat Commun ; 11(1): 2679, 2020 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-32471994

RESUMO

The cation channel transient receptor potential vanilloid 4 (TRPV4) is one of the few identified ion channels that can directly cause inherited neurodegeneration syndromes, but the molecular mechanisms are unknown. Here, we show that in vivo expression of a neuropathy-causing TRPV4 mutant (TRPV4R269C) causes dose-dependent neuronal dysfunction and axonal degeneration, which are rescued by genetic or pharmacological blockade of TRPV4 channel activity. TRPV4R269C triggers increased intracellular Ca2+ through a Ca2+/calmodulin-dependent protein kinase II (CaMKII)-mediated mechanism, and CaMKII inhibition prevents both increased intracellular Ca2+ and neurotoxicity in Drosophila and cultured primary mouse neurons. Importantly, TRPV4 activity impairs axonal mitochondrial transport, and TRPV4-mediated neurotoxicity is modulated by the Ca2+-binding mitochondrial GTPase Miro. Our data highlight an integral role for CaMKII in neuronal TRPV4-associated Ca2+ responses, the importance of tightly regulated Ca2+ dynamics for mitochondrial axonal transport, and the therapeutic promise of TRPV4 antagonists for patients with TRPV4-related neurodegenerative diseases.


Assuntos
Sinalização do Cálcio/fisiologia , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Drosophila melanogaster/metabolismo , Doenças Neurodegenerativas/genética , Canais de Cátion TRPV/genética , Animais , Animais Geneticamente Modificados , Axônios/patologia , Cálcio/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/antagonistas & inibidores , Células Cultivadas , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismo , Doenças Neurodegenerativas/patologia , Asas de Animais/crescimento & desenvolvimento
10.
Invest Ophthalmol Vis Sci ; 61(5): 51, 2020 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-32460313

RESUMO

Purpose: The purpose of this study was to determine if treatment with telmisartan, an angiotensin II type 1 receptor blocker (ARB), protects against retinal ganglion cell (RGC) degeneration in a mouse glaucoma model with induced elevation of intraocular pressure (IOP). Methods: IOP elevation was induced by injection of polystyrene microbeads into the anterior chamber of the right eye of 3-month-old C57BL/6J mice, with the left eye serving as contralateral control. Starting the day of microbead injection, mice were maintained on solid food pellets with or without incorporated telmisartan. IOP was measured by Tono Lab tonometry prior to and weekly after microbead injection. Twelve weeks postinjection, mice were euthanized to obtain optic nerves for analysis of RGC axons. The total numbers of optic nerve axons were determined manually and automatedly using AxonJ. Degenerating axons were counted manually. Results: IOP elevation induced by microbead injection was similar in magnitude and duration in vehicle and telmisartan-fed mice, although IOP was reduced 5.8% in uninjected mice treated with telmisartan (P = 0.0027). Axon loss determined by manual and automated methods was greater in vehicle compared to telmisartan-treated mice (manual: 9.5% vs. 1.8%, P = 0.044; automated: 14.2% vs. 2.9%, P = 0.0375). An increase in the percent of axons undergoing degeneration was observed in nerves from microbead-injected eyes that was greater in vehicle-treated compared to telmisartan-treated mice (49.0% vs. -0.58%, P = 0.0019). Conclusions: Elevation of IOP by microbead injection led to loss of RGC axons in vehicle-treated mice that was largely prevented by telmisartan treatment, suggesting a neuroprotective effect of telmisartan.


Assuntos
Bloqueadores do Receptor Tipo 1 de Angiotensina II/farmacologia , Bloqueadores do Receptor Tipo 1 de Angiotensina II/uso terapêutico , Axônios/efeitos dos fármacos , Axônios/patologia , Glaucoma/tratamento farmacológico , Glaucoma/patologia , Células Ganglionares da Retina/efeitos dos fármacos , Células Ganglionares da Retina/patologia , Telmisartan/farmacologia , Telmisartan/uso terapêutico , Animais , Modelos Animais de Doenças , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL
11.
Nature ; 581(7806): 77-82, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32376949

RESUMO

Grafts of spinal-cord-derived neural progenitor cells (NPCs) enable the robust regeneration of corticospinal axons and restore forelimb function after spinal cord injury1; however, the molecular mechanisms that underlie this regeneration are unknown. Here we perform translational profiling specifically of corticospinal tract (CST) motor neurons in mice, to identify their 'regenerative transcriptome' after spinal cord injury and NPC grafting. Notably, both injury alone and injury combined with NPC grafts elicit virtually identical early transcriptomic responses in host CST neurons. However, in mice with injury alone this regenerative transcriptome is downregulated after two weeks, whereas in NPC-grafted mice this transcriptome is sustained. The regenerative transcriptome represents a reversion to an embryonic transcriptional state of the CST neuron. The huntingtin gene (Htt) is a central hub in the regeneration transcriptome; deletion of Htt significantly attenuates regeneration, which shows that Htt has a key role in neural plasticity after injury.


Assuntos
Proliferação de Células/genética , Embrião de Mamíferos/citologia , Embrião de Mamíferos/metabolismo , Regeneração Nervosa/genética , Células-Tronco Neurais/citologia , Neurônios/metabolismo , Neurônios/patologia , Transcrição Genética , Animais , Axônios/patologia , Axônios/fisiologia , Modelos Animais de Doenças , Feminino , Perfilação da Expressão Gênica , Proteína Huntingtina/genética , Camundongos , Células-Tronco Neurais/transplante , Plasticidade Neuronal , Neurônios/citologia , Neurônios/transplante , Biossíntese de Proteínas , Tratos Piramidais/citologia , Tratos Piramidais/metabolismo , Tratos Piramidais/patologia , RNA-Seq , Traumatismos da Medula Espinal/genética , Traumatismos da Medula Espinal/patologia , Transcriptoma
12.
PLoS One ; 15(5): e0233700, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32469963

RESUMO

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive decline and amyloid-beta (Aß) depositions generated by the proteolysis of amyloid precursor protein (APP) in the brain. In APPNL-F mice, APP gene was humanized and contains two familial AD mutations, and APP-unlike other mouse models of AD-is driven by the endogenous mouse APP promoter. Similar to people without apparent cognitive dysfunction but with heavy Aß plaque load, we found no significant decline in the working memory of adult APPNL-F mice, but these mice showed decline in the expression of normal anxiety. Using immunohistochemistry and 3D block-face scanning electron microscopy, we found no changes in GABAA receptor positivity and size of somatic and dendritic synapses of hippocampal interneurons. We did not find alterations in the level of expression of perineuronal nets around parvalbumin (PV) interneurons or in the density of PV- or somatostatin-positive hippocampal interneurons. However, in contrast to other investigated cell types, PV interneuron axons were occasionally mildly dystrophic around Aß plaques, and the synapses of PV-positive axon initial segment (AIS)-targeting interneurons were significantly enlarged. Our results suggest that PV interneurons are highly resistant to amyloidosis in APPNL-F mice and amyloid-induced increase in hippocampal pyramidal cell excitability may be compensated by PV-positive AIS-targeting cells. Mechanisms that make PV neurons more resilient could therefore be exploited in the treatment of AD for mitigating Aß-related inflammatory effects on neurons.


Assuntos
Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Hipocampo/metabolismo , Interneurônios/metabolismo , Mutação , Rede Nervosa/metabolismo , Fragmentos de Peptídeos/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/genética , Animais , Axônios/metabolismo , Axônios/patologia , Hipocampo/patologia , Humanos , Interneurônios/patologia , Memória de Curto Prazo , Camundongos , Camundongos Transgênicos , Rede Nervosa/patologia , Fragmentos de Peptídeos/genética , Células Piramidais/metabolismo , Células Piramidais/patologia , Receptores de GABA-A/genética , Receptores de GABA-A/metabolismo
13.
PLoS One ; 15(4): e0231598, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32310954

RESUMO

The microstructure changes associated with degeneration of spinal axons in amyotrophic lateral sclerosis (ALS) may be reflected in altered water diffusion properties, potentially detectable with diffusion-weighted (DW) MRI. Prior work revealed the classical mono-exponential model fails to precisely depict decay in DW signal at high b-values. In this study, we aim to investigate signal decay behaviors at ultra-high b-values for non-invasive assessment of spinal cord alterations in the transgenic SOD1G93A mouse model of ALS. A multiexponential diffusion analysis using regularized non-negative least squares (rNNLS) algorithm was applied to a series of thirty DW MR images with b-values ranging from 0 to 858,022 s/mm2 on ex vivo spinal cords of transgenic SOD1G93A and age-matched control mice. We compared the distributions of measured diffusion coefficient fractions between the groups. The measured diffusion weighted signals in log-scale showed non-linear decay behaviors with increased b-values. Faster signal decays were observed with diffusion gradients applied parallel to the long axis of the spinal cord compared to when oriented in the transverse direction. Multiexponential analysis at the lumbar level in the spinal cord identified ten subintervals. A significant decrease of diffusion coefficient fractions was found in the ranges of [1.63×10-8,3.70×10-6] mm2/s (P = 0.0002) and of [6.01×10-6,4.20×10-5] mm2/s (P = 0.0388) in SOD1G93A mice. Anisotropic diffusion signals persisted at ultra-high b-value DWIs of the mouse spinal cord and multiexponential diffusion analysis offers the potential to evaluate microstructural alterations of ALS-affected spinal cord non-invasively.


Assuntos
Algoritmos , Esclerose Amiotrófica Lateral/diagnóstico por imagem , Axônios/patologia , Imagem de Difusão por Ressonância Magnética/métodos , Medula Espinal/diagnóstico por imagem , Esclerose Amiotrófica Lateral/genética , Esclerose Amiotrófica Lateral/patologia , Animais , Masculino , Camundongos , Medula Espinal/patologia , Superóxido Dismutase-1/genética
14.
J Integr Neurosci ; 19(1): 125-129, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-32259893

RESUMO

Autosomal recessive cerebellar ataxias comprise many types of diseases. The most frequent autosomal recessive cerebellar ataxias are Friedreich ataxia, but other types are relatively rare. We encountered a consanguineous family with two cases of late-onset cerebellar ataxia with neuropathy. We performed whole-exome sequencing in one patient and confirmed by Sanger sequencing in other family members. Neurological examination revealed cerebellar ataxia, hand tremor, and neck dystonia, distal muscle wasting, and diminished tendon reflexes. The patients had no conjunctival telangiectasia or immunodeficiency. Blood examination revealed slightly elevated α-fetoprotein. Brain MRI demonstrated marked cerebellar atrophy and mild brainstem atrophy. The electrophysiologic study and nerve biopsy showed axonal neuropathy. Whole-exome sequencing revealed a novel homozygous missense variant (NM_000051.3: c.496G > C) in the ataxia-telangiectasia mutated gene. This homozygous variant was found in another patient, co-segregated within the family members-this variant results in aberrant splicing (skipping exon 5) on RT-PCR analysis. We identified the ataxia-telangiectasia mutated variant in an adult, late-onset autosomal recessive cerebellar ataxias family. We should consider ataxia-telangiectasia even in late-onset autosomal recessive cerebellar ataxias without telangiectasia or immunodeficiency.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/genética , Degenerações Espinocerebelares/genética , Degenerações Espinocerebelares/patologia , Adulto , Axônios/patologia , Encéfalo/patologia , Feminino , Humanos , Masculino , Mutação , Linhagem , Degenerações Espinocerebelares/fisiopatologia , Sequenciamento Completo do Exoma
15.
Toxicol Appl Pharmacol ; 393: 114955, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-32171569

RESUMO

Inorganic arsenic is among the major contaminants of groundwater in the world. Worldwide population-based studies demonstrate that chronic arsenic exposure is associated with poor cognitive performance among children and adults, while research in animal models confirms learning and memory deficits after arsenic exposure. The aim of this study was to investigate the long-term effects of environmentally relevant arsenic exposure in the myelination process of the prefrontal cortex (PFC) and corpus callosum (CC). A longitudinal study with repeated follow-up assessments was performed in male Wistar rats exposed to 3 ppm sodium arsenite in drinking water. Animals received the treatment from gestation until 2, 4, 6, or 12 months of postnatal age. The levels of myelin basic protein (MBP) were evaluated by immunohistochemistry/histology and immunoblotting from the PFC and CC. As plausible alterations associated with demyelination, we considered mitochondrial mass (VDAC) and two axonal damage markers: amyloid precursor protein (APP) level and phosphorylated neurofilaments. To analyze the microstructure of the CC in vivo, we acquired diffusion-weighted images at the same ages, from which we derived metrics using the tensor model. Significantly decreased levels of MBP were found in both regions together with significant increases of mitochondrial mass and slight axonal damage at 12 months in the PFC. Ultrastructural imaging demonstrated arsenic-associated decreases of white matter volume, water diffusion anisotropy, and increases in radial diffusivity. This study indicates that arsenic exposure is associated with a significant and persistent negative impact on microstructural features of white matter tracts.


Assuntos
Intoxicação por Arsênico/patologia , Doenças Desmielinizantes/patologia , Envelhecimento , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Intoxicação por Arsênico/diagnóstico por imagem , Arsenitos/toxicidade , Axônios/patologia , Corpo Caloso/patologia , Doenças Desmielinizantes/diagnóstico por imagem , Imagem de Tensor de Difusão , Água Potável , Imuno-Histoquímica , Masculino , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Proteína Básica da Mielina/metabolismo , Proteínas de Neurofilamentos/metabolismo , Córtex Pré-Frontal/patologia , Ratos , Ratos Wistar , Compostos de Sódio/toxicidade , Substância Branca/diagnóstico por imagem , Substância Branca/patologia
16.
Brain ; 143(3): 783-799, 2020 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-32185393

RESUMO

Frontotemporal dementia and amyotrophic lateral sclerosis are clinically and pathologically overlapping disorders with shared genetic causes. We previously identified a disease locus on chromosome 16p12.1-q12.2 with genome-wide significant linkage in a large European Australian family with autosomal dominant inheritance of frontotemporal dementia and amyotrophic lateral sclerosis and no mutation in known amyotrophic lateral sclerosis or dementia genes. Here we demonstrate the segregation of a novel missense variant in CYLD (c.2155A>G, p.M719V) within the linkage region as the genetic cause of disease in this family. Immunohistochemical analysis of brain tissue from two CYLD p.M719V mutation carriers showed widespread glial CYLD immunoreactivity. Primary mouse neurons transfected with CYLDM719V exhibited increased cytoplasmic localization of TDP-43 and shortened axons. CYLD encodes a lysine 63 deubiquitinase and CYLD cutaneous syndrome, a skin tumour disorder, is caused by mutations that lead to reduced deubiquitinase activity. In contrast with CYLD cutaneous syndrome-causative mutations, CYLDM719V exhibited significantly increased lysine 63 deubiquitinase activity relative to the wild-type enzyme (paired Wilcoxon signed-rank test P = 0.005). Overexpression of CYLDM719V in HEK293 cells led to more potent inhibition of the cell signalling molecule NF-κB and impairment of autophagosome fusion to lysosomes, a key process in autophagy. Although CYLD mutations appear to be rare, CYLD's interaction with at least three other proteins encoded by frontotemporal dementia and/or amyotrophic lateral sclerosis genes (TBK1, OPTN and SQSTM1) suggests that it may play a central role in the pathogenesis of these disorders. Mutations in several frontotemporal dementia and amyotrophic lateral sclerosis genes, including TBK1, OPTN and SQSTM1, result in a loss of autophagy function. We show here that increased CYLD activity also reduces autophagy function, highlighting the importance of autophagy regulation in the pathogenesis of frontotemporal dementia and amyotrophic lateral sclerosis.


Assuntos
Esclerose Amiotrófica Lateral/genética , Enzima Desubiquitinante CYLD/genética , Enzima Desubiquitinante CYLD/fisiologia , Demência Frontotemporal/genética , Predisposição Genética para Doença/genética , Esclerose Amiotrófica Lateral/metabolismo , Animais , Autofagossomos/metabolismo , Autofagossomos/fisiologia , Axônios/patologia , Encéfalo/metabolismo , Proteínas de Ligação a DNA , Enzima Desubiquitinante CYLD/metabolismo , Enzimas Desubiquitinantes/metabolismo , Demência Frontotemporal/metabolismo , Camundongos , Mutação de Sentido Incorreto/genética , NF-kappa B/antagonistas & inibidores , Cultura Primária de Células , Transfecção
17.
Invest Ophthalmol Vis Sci ; 61(3): 11, 2020 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-32176262

RESUMO

Purpose: To define remodeling of photoreceptor synaptic terminals and second-order retinal neurons in canine X-linked progressive retinal atrophy 1 caused by a five-nucleotide deletion in the RPGR exon ORF15. Methods: Retinas of normal and mutant dogs were used for gene expression, Western blot, and immunohistochemistry. Cell-specific markers were used to examine disease-dependent retinal remodeling. Results: In mutant retinas, a number of rod axon terminals retract into the outer nuclear layer. This neuritic atrophy preceded significant loss of rods and was evident early in disease. Rod bipolar and horizontal cell processes were found to extend into the outer nuclear layer, where they seemed to form contacts with the spherules of rod photoreceptors. No ectopic rewiring was observed. Because cytoskeletal reorganization was previously shown to underlie photoreceptor axon retraction, we examined normal and mutant retinas for expression of axon guidance receptors ROBO1 and ROBO2, which are known to regulate actin cytoskeleton dynamics. We found that the overall expression of both ROBO1 and ROBO2 is retained at the same level in premature and fully developed normal retinas. However, analysis of predisease and early disease retinas identified markedly decreased levels of ROBO1 in rod spherules compared with controls. In contrast, no differences in ROBO1 signals were noted in cone pedicles in normal and mutant retinas, where ROBO1 levels remained similarly low. Conclusions: Depletion of ROBO1 in rod synaptic terminals correlates with the remodeling of axonal and dendritic processes in the outer retina of dogs with X-linked progressive retinal atrophy 1 and may play a role in the retraction of rod axons.


Assuntos
Doenças do Cão/metabolismo , Doenças Genéticas Ligadas ao Cromossomo X/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Terminações Pré-Sinápticas/metabolismo , Receptores Imunológicos/metabolismo , Degeneração Retiniana/metabolismo , Animais , Orientação de Axônios/fisiologia , Axônios/patologia , Doenças do Cão/genética , Doenças do Cão/patologia , Cães , Proteínas do Olho/genética , Proteínas do Olho/metabolismo , Doenças Genéticas Ligadas ao Cromossomo X/genética , Doenças Genéticas Ligadas ao Cromossomo X/patologia , Doenças Genéticas Ligadas ao Cromossomo X/veterinária , Microscopia Confocal , Proteínas do Tecido Nervoso/deficiência , Plasticidade Neuronal/fisiologia , Terminações Pré-Sinápticas/patologia , Receptores Imunológicos/deficiência , Retina/metabolismo , Degeneração Retiniana/genética , Degeneração Retiniana/patologia , Degeneração Retiniana/veterinária , Neurônios Retinianos/metabolismo , Neurônios Retinianos/patologia , Células Fotorreceptoras Retinianas Bastonetes/metabolismo , Células Fotorreceptoras Retinianas Bastonetes/patologia
18.
PLoS One ; 15(3): e0230080, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32155215

RESUMO

Human bone marrow-derived mesenchymal stem/stromal cells (hMSCs) have shown potential in facilitating recovery from spinal cord injury (SCI) through communicating with microglia/macrophages (MG/MΦ). We here focused on chemokines as a candidate for the communication. Selected MG/MΦ-related chemokines were determined gene expression after SCI and further focused CCL2/CCR2 and CCL5/CCR5 to estimate role of the chemokines by hMSCs. Male C57/BL6 mice were subjected to spinal cord transection. Gene expression was assayed in the spinal cords following SCI for selected MG/MΦ-related chemokines and their receptors. hMSCs (5×105 cells) were then transplanted into parenchyma of the spinal cord, and the expressions of the Ccl2/Ccr2 and Ccl5/Ccr5 axes, inflammation, MG/MΦ-polarization, and axonal regeneration were evaluated to measure the influence of the hMSCs. Finally, mouse CCL5 was injected into the spinal cords. Acute increases in gene expression after SCI were observed for most chemokines, including Ccl2; chronic increases were observed for Ccl5. CCL2+-cells merged with NeuN+-neurons. CCR2+ immunoreactivity was principally observed in Ly-6G+/iNOS+-granulocytes on postoperative day (pod) 1, and CCL5+ and CCR5+ immunoreactivity overlapped with NeuN+-neurons and F4/80+-MG/MΦ on pod 14. The hMSC transplantation enhanced Ccl2 and Ccl5 and improved locomotor activity. The hMSC implantation did not alter the number of Ly-6G+/CCR2+ but decreased Il1, Elane, and Mpo on pod 3. Conversely, hMSC transplantation increased expression of Zc3h12a (encodes MCP-1-induced protein) on pod 14. Moreover, hMSC increased the Aif1, and two alternatively activated macrophage (AAM)-related genes, Arg1 and Chil3 (Ym1), as well as axonal regenerative markers, Dpysl2 and Gap43. Gene expression indicative of AAM polarization and axonal regeneration were partially recovered by CCL5 injection. These results suggest that hMSC implantation increases Ccl2 and Ccl5, improves locomotor activity, enhances MG/MΦ polarization to AAM, and increases the gene expression of axonal regenerative markers. These functions of hMSCs might be partially mediated by the CCL2/CCR2 and CCL5/CCR5 axes.


Assuntos
Axônios/patologia , Quimiocina CCL2/farmacologia , Quimiocina CCL5/farmacologia , Transplante de Células-Tronco Mesenquimais , Traumatismos da Medula Espinal/terapia , Animais , Axônios/efeitos dos fármacos , Quimiocina CCL2/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Masculino , Camundongos Endogâmicos C57BL , Receptores CCR2/metabolismo , Traumatismos da Medula Espinal/metabolismo , Traumatismos da Medula Espinal/patologia
19.
Neuron ; 106(4): 589-606.e6, 2020 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-32169171

RESUMO

ACOX1 (acyl-CoA oxidase 1) encodes the first and rate-limiting enzyme of the very-long-chain fatty acid (VLCFA) ß-oxidation pathway in peroxisomes and leads to H2O2 production. Unexpectedly, Drosophila (d) ACOX1 is mostly expressed and required in glia, and loss of ACOX1 leads to developmental delay, pupal death, reduced lifespan, impaired synaptic transmission, and glial and axonal loss. Patients who carry a previously unidentified, de novo, dominant variant in ACOX1 (p.N237S) also exhibit glial loss. However, this mutation causes increased levels of ACOX1 protein and function resulting in elevated levels of reactive oxygen species in glia in flies and murine Schwann cells. ACOX1 (p.N237S) patients exhibit a severe loss of Schwann cells and neurons. However, treatment of flies and primary Schwann cells with an antioxidant suppressed the p.N237S-induced neurodegeneration. In summary, both loss and gain of ACOX1 lead to glial and neuronal loss, but different mechanisms are at play and require different treatments.


Assuntos
Acil-CoA Oxidase/genética , Axônios/enzimologia , Degeneração Neural/genética , Neuroglia/enzimologia , Animais , Axônios/patologia , Drosophila , Humanos , Camundongos , Mutação , Degeneração Neural/enzimologia , Neuroglia/patologia , Ratos
20.
RNA ; 26(5): 595-612, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32051223

RESUMO

Axonal protein synthesis has been shown to play a role in developmental and regenerative growth, as well as in the maintenance of the axoplasm in a steady state. Recent studies have begun to identify the mRNAs localized in axons, which could be translated locally under different conditions. Despite that by now hundreds or thousands of mRNAs have been shown to be localized into the axonal compartment of cultured neurons in vitro, knowledge of which mRNAs are localized in mature myelinated axons is quite limited. With the purpose of characterizing the transcriptome of mature myelinated motor axons of peripheral nervous systems, we modified the axon microdissection method devised by Koenig, enabling the isolation of the axoplasm RNA to perform RNA-seq analysis. The transcriptome analysis indicates that the number of RNAs detected in mature axons is lower in comparison with in vitro data, depleted of glial markers, and enriched in neuronal markers. The mature myelinated axons are enriched for mRNAs related to cytoskeleton, translation, and oxidative phosphorylation. Moreover, it was possible to define core genes present in axons when comparing our data with transcriptomic data of axons grown in different conditions. This work provides evidence that axon microdissection is a valuable method to obtain genome-wide data from mature and myelinated axons of the peripheral nervous system, and could be especially useful for the study of axonal involvement in neurodegenerative pathologies of motor neurons such as amyotrophic lateral sclerosis (ALS) and spinal muscular atrophies (SMA).


Assuntos
Esclerose Amiotrófica Lateral/genética , Neurônios Motores/metabolismo , Atrofia Muscular Espinal/genética , RNA/genética , Esclerose Amiotrófica Lateral/metabolismo , Animais , Axônios/metabolismo , Axônios/patologia , Diferenciação Celular/genética , Perfilação da Expressão Gênica , Humanos , Microdissecção , Atrofia Muscular Espinal/metabolismo , Atrofia Muscular Espinal/patologia , Sistema Nervoso Periférico/metabolismo , Sistema Nervoso Periférico/patologia , RNA Mensageiro/genética , RNA-Seq , Transcriptoma/genética
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