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1.
J Neurol Neurosurg Psychiatry ; 92(3): 295-302, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33184094

RESUMO

OBJECTIVE: To establish a rigorous, expert-led, evidence-based approach to the evaluation of licensed drugs for repurposing and testing in clinical trials of people with progressive multiple sclerosis (MS). METHODS: We long-listed licensed drugs with evidence of human safety, blood-brain barrier penetrance and demonstrable efficacy in at least one animal model, or mechanistic target, agreed by a panel of experts and people with MS to be relevant to the pathogenesis of progression. We systematically reviewed the preclinical and clinical literature for each compound, condensed this into a database of summary documents and short-listed drugs by scoring each one of them. Drugs were evaluated for immediate use in a clinical trial, and our selection was scrutinised by a final independent expert review. RESULTS: From a short list of 55 treatments, we recommended four treatments for immediate testing in progressive MS: R-α-lipoic acid, metformin, the combination treatment of R-α-lipoic acid and metformin, and niacin. We also prioritised clemastine, lamotrigine, oxcarbazepine, nimodipine and flunarizine. CONCLUSIONS: We report a standardised approach for the identification of candidate drugs for repurposing in the treatment of progressive MS.


Assuntos
Reposicionamento de Medicamentos , Esclerose Múltipla Crônica Progressiva/tratamento farmacológico , Animais , Avaliação de Medicamentos , Humanos
2.
J Pathol ; 247(4): 422-434, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30565681

RESUMO

The overall survival for patients with primary glioblastoma is very poor. Glioblastoma contains a subpopulation of glioma stem cells (GSC) that are responsible for tumour initiation, treatment resistance and recurrence. PPARα is a transcription factor involved in the control of lipid, carbohydrate and amino acid metabolism. We have recently shown that PPARα gene and protein expression is increased in glioblastoma and has independent clinical prognostic significance in multivariate analyses. In this work, we report that PPARα is overexpressed in GSC compared to foetal neural stem cells. To investigate the role of PPARα in GSC, we knocked down its expression using lentiviral transduction with short hairpin RNA (shRNA). Transduced GSC were tagged with luciferase and stereotactically xenografted into the striatum of NOD-SCID mice. Bioluminescent and magnetic resonance imaging showed that knockdown (KD) of PPARα reduced the tumourigenicity of GSC in vivo. PPARα-expressing control GSC xenografts formed invasive histological phenocopies of human glioblastoma, whereas PPARα KD GSC xenografts failed to establish viable intracranial tumours. PPARα KD GSC showed significantly reduced proliferative capacity and clonogenic potential in vitro with an increase in cellular senescence. In addition, PPARα KD resulted in significant downregulation of the stem cell factors c-Myc, nestin and SOX2. This was accompanied by downregulation of the PPARα-target genes and key regulators of fatty acid oxygenation ACOX1 and CPT1A, with no compensatory increase in glycolytic flux. These data establish the aberrant overexpression of PPARα in GSC and demonstrate that this expression functions as an important regulator of tumourigenesis, linking self-renewal and the malignant phenotype in this aggressive cancer stem cell subpopulation. We conclude that targeting GSC PPARα expression may be a therapeutically beneficial strategy with translational potential as an adjuvant treatment. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.


Assuntos
Neoplasias Encefálicas/patologia , Glioblastoma/patologia , PPAR alfa/metabolismo , RNA Interferente Pequeno/farmacologia , Animais , Biomarcadores Tumorais/metabolismo , Transformação Celular Neoplásica , Regulação para Baixo , Feminino , Regulação Neoplásica da Expressão Gênica/fisiologia , Técnicas de Silenciamento de Genes/métodos , Humanos , Lentivirus , Camundongos Endogâmicos NOD , Camundongos SCID , Células-Tronco Neoplásicas/patologia , Fenótipo , Transdução de Sinais/fisiologia , Transplante Heterólogo , Células Tumorais Cultivadas
3.
Ann Neurol ; 83(4): 779-793, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29534309

RESUMO

OBJECTIVE: Friedreich's ataxia is an incurable inherited neurological disease caused by frataxin deficiency. Here, we report the neuroreparative effects of myeloablative allogeneic bone marrow transplantation in a humanized murine model of the disease. METHODS: Mice received a transplant of fluorescently tagged sex-mismatched bone marrow cells expressing wild-type frataxin and were assessed at monthly intervals using a range of behavioral motor performance tests. At 6 months post-transplant, mice were euthanized for protein and histological analysis. In an attempt to augment numbers of bone marrow-derived cells integrating within the nervous system and improve therapeutic efficacy, a subgroup of transplanted mice also received monthly subcutaneous infusions of the cytokines granulocyte-colony stimulating factor and stem cell factor. RESULTS: Transplantation caused improvements in several indicators of motor coordination and locomotor activity. Elevations in frataxin levels and antioxidant defenses were detected. Abrogation of disease pathology throughout the nervous system was apparent, together with extensive integration of bone marrow-derived cells in areas of nervous tissue injury that contributed genetic material to mature neurons, satellite-like cells, and myelinating Schwann cells by processes including cell fusion. Elevations in circulating bone marrow-derived cell numbers were detected after cytokine administration and were associated with increased frequencies of Purkinje cell fusion and bone marrow-derived dorsal root ganglion satellite-like cells. Further improvements in motor coordination and activity were evident. INTERPRETATION: Our data provide proof of concept of gene replacement therapy, via allogeneic bone marrow transplantation, that reverses neurological features of Friedreich's ataxia with the potential for rapid clinical translation. Ann Neurol 2018;83:779-793.


Assuntos
Transplante de Medula Óssea/métodos , Ataxia de Friedreich/cirurgia , Animais , Peso Corporal/fisiologia , Citocinas/metabolismo , Modelos Animais de Doenças , Comportamento Exploratório/fisiologia , Ataxia de Friedreich/genética , Gânglios Espinais/patologia , Fator Estimulador de Colônias de Granulócitos/metabolismo , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Proteínas de Ligação ao Ferro/genética , Leucócitos Mononucleares/patologia , Camundongos , Camundongos Endogâmicos C57BL , Força Muscular/fisiologia , Mutação/genética , Proteínas do Tecido Nervoso/metabolismo , Neurônios/patologia , Frataxina
4.
JAMA ; 321(2): 175-187, 2019 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-30644981

RESUMO

Importance: Within 2 decades of onset, 80% of untreated patients with relapsing-remitting multiple sclerosis (MS) convert to a phase of irreversible disability accrual termed secondary progressive MS. The association between disease-modifying treatments (DMTs), and this conversion has rarely been studied and never using a validated definition. Objective: To determine the association between the use, the type of, and the timing of DMTs with the risk of conversion to secondary progressive MS diagnosed with a validated definition. Design, Setting, and Participants: Cohort study with prospective data from 68 neurology centers in 21 countries examining patients with relapsing-remitting MS commencing DMTs (or clinical monitoring) between 1988-2012 with minimum 4 years' follow-up. Exposures: The use, type, and timing of the following DMTs: interferon beta, glatiramer acetate, fingolimod, natalizumab, or alemtuzumab. After propensity-score matching, 1555 patients were included (last follow-up, February 14, 2017). Main Outcome and Measure: Conversion to objectively defined secondary progressive MS. Results: Of the 1555 patients, 1123 were female (mean baseline age, 35 years [SD, 10]). Patients initially treated with glatiramer acetate or interferon beta had a lower hazard of conversion to secondary progressive MS than matched untreated patients (HR, 0.71; 95% CI, 0.61-0.81; P < .001; 5-year absolute risk, 12% [49 of 407] vs 27% [58 of 213]; median follow-up, 7.6 years [IQR, 5.8-9.6]), as did fingolimod (HR, 0.37; 95% CI, 0.22-0.62; P < .001; 5-year absolute risk, 7% [6 of 85] vs 32% [56 of 174]; median follow-up, 4.5 years [IQR, 4.3-5.1]); natalizumab (HR, 0.61; 95% CI, 0.43-0.86; P = .005; 5-year absolute risk, 19% [16 of 82] vs 38% [62 of 164]; median follow-up, 4.9 years [IQR, 4.4-5.8]); and alemtuzumab (HR, 0.52; 95% CI, 0.32-0.85; P = .009; 5-year absolute risk, 10% [4 of 44] vs 25% [23 of 92]; median follow-up, 7.4 years [IQR, 6.0-8.6]). Initial treatment with fingolimod, alemtuzumab, or natalizumab was associated with a lower risk of conversion than initial treatment with glatiramer acetate or interferon beta (HR, 0.66; 95% CI, 0.44-0.99; P = .046); 5-year absolute risk, 7% [16 of 235] vs 12% [46 of 380]; median follow-up, 5.8 years [IQR, 4.7-8.0]). The probability of conversion was lower when glatiramer acetate or interferon beta was started within 5 years of disease onset vs later (HR, 0.77; 95% CI, 0.61-0.98; P = .03; 5-year absolute risk, 3% [4 of 120] vs 6% [2 of 38]; median follow-up, 13.4 years [IQR, 11-18.1]). When glatiramer acetate or interferon beta were escalated to fingolimod, alemtuzumab, or natalizumab within 5 years vs later, the HR was 0.76 (95% CI, 0.66-0.88; P < .001; 5-year absolute risk, 8% [25 of 307] vs 14% [46 of 331], median follow-up, 5.3 years [IQR], 4.6-6.1). Conclusions and Relevance: Among patients with relapsing-remitting MS, initial treatment with fingolimod, alemtuzumab, or natalizumab was associated with a lower risk of conversion to secondary progressive MS vs initial treatment with glatiramer acetate or interferon beta. These findings, considered along with these therapies' risks, may help inform decisions about DMT selection.


Assuntos
Fatores Imunológicos/uso terapêutico , Esclerose Múltipla Recidivante-Remitente/tratamento farmacológico , Adulto , Alemtuzumab/uso terapêutico , Estudos de Coortes , Progressão da Doença , Feminino , Cloridrato de Fingolimode/uso terapêutico , Acetato de Glatiramer/uso terapêutico , Humanos , Imunossupressores/uso terapêutico , Interferon beta/uso terapêutico , Masculino , Natalizumab/uso terapêutico , Tempo para o Tratamento
5.
Ann Neurol ; 81(2): 212-226, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28009062

RESUMO

OBJECTIVES: Friedreich's ataxia is a devastating neurological disease currently lacking any proven treatment. We studied the neuroprotective effects of the cytokines, granulocyte-colony stimulating factor (G-CSF) and stem cell factor (SCF) in a humanized murine model of Friedreich's ataxia. METHODS: Mice received monthly subcutaneous infusions of cytokines while also being assessed at monthly time points using an extensive range of behavioral motor performance tests. After 6 months of treatment, neurophysiological evaluation of both sensory and motor nerve conduction was performed. Subsequently, mice were sacrificed for messenger RNA, protein, and histological analysis of the dorsal root ganglia, spinal cord, and cerebellum. RESULTS: Cytokine administration resulted in significant reversal of biochemical, neuropathological, neurophysiological, and behavioural deficits associated with Friedreich's ataxia. Both G-CSF and SCF had pronounced effects on frataxin levels (the primary molecular defect in the pathogenesis of the disease) and a regulators of frataxin expression. Sustained improvements in motor coordination and locomotor activity were observed, even after onset of neurological symptoms. Treatment also restored the duration of sensory nerve compound potentials. Improvements in peripheral nerve conduction positively correlated with cytokine-induced increases in frataxin expression, providing a link between increases in frataxin and neurophysiological function. Abrogation of disease-related pathology was also evident, with reductions in inflammation/gliosis and increased neural stem cell numbers in areas of tissue injury. INTERPRETATION: These experiments show that cytokines already clinically used in other conditions offer the prospect of a novel, rapidly translatable, disease-modifying, and neuroprotective treatment for Friedreich's ataxia. Ann Neurol 2017;81:212-226.


Assuntos
Comportamento Animal/efeitos dos fármacos , Ataxia de Friedreich/tratamento farmacológico , Fator Estimulador de Colônias de Granulócitos/farmacologia , Proteínas de Ligação ao Ferro/metabolismo , Condução Nervosa/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Nervos Periféricos/efeitos dos fármacos , Fator de Células-Tronco/farmacologia , Animais , Modelos Animais de Doenças , Ataxia de Friedreich/metabolismo , Ataxia de Friedreich/fisiopatologia , Fator Estimulador de Colônias de Granulócitos/administração & dosagem , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Fármacos Neuroprotetores/administração & dosagem , Fator de Células-Tronco/administração & dosagem , Frataxina
6.
Acta Neuropathol ; 135(6): 907-921, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29541917

RESUMO

Bone marrow-derived cells are known to infiltrate the adult brain and fuse with cerebellar Purkinje cells. Histological observations that such heterotypic cell fusion events are substantially more frequent following cerebellar injury suggest they could have a role in the protection of mature brain neurons. To date, the possibility that cell fusion can preserve or restore the structure and function of adult brain neurons has not been directly addressed; indeed, though frequently suggested, the possibility of benefit has always been rather speculative. Here we report, for the first time, that fusion of a bone marrow-derived cell with a neuron in vivo, in the mature brain, results in the formation of a spontaneously firing neuron. Notably, we also provide evidence supporting the concept that heterotypic cell fusion acts as a biological mechanism to repair pathological changes in Purkinje cell structure and electrophysiology. We induced chronic central nervous system inflammation in chimeric mice expressing bone marrow cells tagged with enhanced green fluorescent protein. Subsequent in-depth histological analysis revealed significant Purkinje cell injury. In addition, there was an increased incidence of cell fusion between bone marrow-derived cells and Purkinje cells, revealed as enhanced green fluorescent protein-expressing binucleate heterokaryons. These fused cells resembled healthy Purkinje cells in their morphology, soma size, ability to synthesize the neurotransmitter gamma-aminobutyric acid, and synaptic innervation from neighbouring cells. Extracellular recording of spontaneous firing ex vivo revealed a shift in the predominant mode of firing of non-fused Purkinje cells in the context of cerebellar inflammation. By contrast, the firing patterns of fused Purkinje cells were the same as in healthy control cerebellum, indicating that fusion of bone marrow-derived cells with Purkinje cells mitigated the effects of cell injury on electrical activity. Together, our histological and electrophysiological results provide novel fundamental insights into physiological processes by which nerve cells are protected in adult life.


Assuntos
Células da Medula Óssea/fisiologia , Transplante de Medula Óssea , Encefalomielite Autoimune Experimental/fisiopatologia , Encefalomielite Autoimune Experimental/terapia , Células de Purkinje/fisiologia , Potenciais de Ação/fisiologia , Animais , Células da Medula Óssea/patologia , Fusão Celular , Quimera , Encefalomielite Autoimune Experimental/patologia , Feminino , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Inflamação/patologia , Inflamação/fisiopatologia , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Bainha de Mielina/patologia , Bainha de Mielina/fisiologia , Neuroproteção/fisiologia , Células de Purkinje/patologia , Técnicas de Cultura de Tecidos
7.
Cytotherapy ; 20(1): 21-28, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28917625

RESUMO

BACKGROUND: Clinical trials using ex vivo expansion of autologous mesenchymal stromal cells (MSCs) are in progress for several neurological diseases including multiple sclerosis (MS). Given that environment alters MSC function, we examined whether in vitro expansion, increasing donor age and progressive MS affect the neuroprotective properties of the MSC secretome. METHODS: Comparative analyses of neuronal survival in the presence of MSC-conditioned medium (MSCcm) isolated from control subjects (C-MSCcm) and those with MS (MS-MSCcm) were performed following (1) trophic factor withdrawal and (2) nitric oxide-induced neurotoxicity. RESULTS: Reduced neuronal survival following trophic factor withdrawal was seen in association with increasing expansion of MSCs in vitro and MSC donor age. Controlling for these factors, there was an independent, negative effect of progressive MS. In nitric oxide neurotoxicity, MSCcm-mediated neuroprotection was reduced when C-MSCcm was isolated from higher-passage MSCs and was negatively associated with increasing MSC passage number and donor age. Furthermore, the neuroprotective effect of MSCcm was lost when MSCs were isolated from patients with MS. DISCUSSION: Our findings have significant implications for MSC-based therapy in neurodegenerative conditions, particularly for autologous MSC therapy in MS. Impaired neuroprotection mediated by the MSC secretome in progressive MS may reflect reduced reparative potential of autologous MSC-based therapy in MS and it is likely that the causes must be addressed before the full potential of MSC-based therapy is realized. Additionally, we anticipate that understanding the mechanisms responsible will contribute new insights into MS pathogenesis and may also be of wider relevance to other neurodegenerative conditions.


Assuntos
Envelhecimento/patologia , Progressão da Doença , Células-Tronco Mesenquimais/metabolismo , Esclerose Múltipla/patologia , Esclerose Múltipla/terapia , Fármacos Neuroprotetores/metabolismo , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Meios de Cultivo Condicionados/farmacologia , Humanos , Pessoa de Meia-Idade , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Neuroproteção/efeitos dos fármacos , Óxido Nítrico/metabolismo
8.
Mult Scler ; 24(7): 919-931, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-28548004

RESUMO

BACKGROUND: Autologous bone-marrow-derived cells are currently employed in clinical studies of cell-based therapy in multiple sclerosis (MS) although the bone marrow microenvironment and marrow-derived cells isolated from patients with MS have not been extensively characterised. OBJECTIVES: To examine the bone marrow microenvironment and assess the proliferative potential of multipotent mesenchymal stromal cells (MSCs) in progressive MS. METHODS: Comparative phenotypic analysis of bone marrow and marrow-derived MSCs isolated from patients with progressive MS and control subjects was undertaken. RESULTS: In MS marrow, there was an interstitial infiltrate of inflammatory cells with lymphoid (predominantly T-cell) nodules although total cellularity was reduced. Controlling for age, MSCs isolated from patients with MS had reduced in vitro expansion potential as determined by population doubling time, colony-forming unit assay, and expression of ß-galactosidase. MS MSCs expressed reduced levels of Stro-1 and displayed accelerated shortening of telomere terminal restriction fragments (TRF) in vitro. CONCLUSION: Our results are consistent with reduced proliferative capacity and ex vivo premature ageing of bone-marrow-derived cells, particularly MSCs, in MS. They have significant implication for MSC-based therapies for MS and suggest that accelerated cellular ageing and senescence may contribute to the pathophysiology of progressive MS.


Assuntos
Proliferação de Células , Senescência Celular , Células-Tronco Mesenquimais/patologia , Esclerose Múltipla/patologia , Adulto , Proliferação de Células/fisiologia , Células Cultivadas , Senescência Celular/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nicho de Células-Tronco/fisiologia
9.
Pract Neurol ; 18(6): 472-476, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29848512

RESUMO

Given the intuitive potential of stem cell therapy and limitations of current treatment options for progressive multiple sclerosis (MS), it is not surprising that patients consider undertaking significant clinical and financial risks to access stem cell transplantation. However, while increasing evidence supports autologous haematopoietic stem cell transplantation (AHSCT) in aggressive relapsing-remitting MS, interventions employing haematopoietic or other stem cells should otherwise be considered experimental and recommended only in the context of a properly regulated clinical study. Understandably, most neurologists are unfamiliar with AHSCT procedures and the specific requirements for quality assurance and safety standards, as well as post-procedure precautions and follow-up. Consequently they may feel ill-equipped to advise patients. Here, we highlight important points for discussion in consultations with patients considering stem cell 'tourism' for MS.


Assuntos
Transplante de Células-Tronco Hematopoéticas/métodos , Esclerose Múltipla/psicologia , Esclerose Múltipla/cirurgia , Neurologistas/psicologia , Humanos
10.
Histopathology ; 70(7): 1030-1043, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27926792

RESUMO

AIMS: PPARα agonists are in current clinical use as hypolipidaemic agents and show significant antineoplastic effects in human glioblastoma models. To date however, the expression of PPARα in large-scale glioblastoma datasets has not been examined. We aimed to investigate the expression of the transcription factor PPARα in primary glioblastoma, the relationship between PPARα expression and patients' clinicopathological features and other molecular markers associated with gliomagenesis. METHODS AND RESULTS: With protein immunoblotting techniques and reverse transcription quantitative real-time PCR, PPARα was found to be significantly overexpressed in glioblastoma compared with control brain tissue (P = 0.032 and P = 0.005). PPARA gene expression was found to be enriched in the classical glioblastoma subtype within The Cancer Genome Atlas (TCGA) dataset. Although not associated with overall survival when assessed by immunohistochemistry, cross-validation with the TCGA dataset and multivariate analyses identified PPARA gene expression as an independent prognostic marker for overall survival (P = 0.042). Finally, hierarchical clustering revealed novel, significant associations between high PPARA expression and a putative set of glioblastoma molecular mediators including EMX2, AQP4, and NTRK2. CONCLUSIONS: PPARα is overexpressed in primary glioblastoma and high PPARA expression functions as an independent prognostic marker in the glioblastoma TCGA dataset. Further studies are required to explore genetic associations with high PPARA expression and to analyse the predictive role of PPARα expression in glioblastoma models in response to PPARα agonists.


Assuntos
Biomarcadores Tumorais/análise , Neoplasias Encefálicas/patologia , Glioblastoma/patologia , PPAR alfa/biossíntese , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/mortalidade , Criança , Feminino , Glioblastoma/metabolismo , Glioblastoma/mortalidade , Humanos , Isocitrato Desidrogenase/genética , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , PPAR alfa/análise , Prognóstico , Modelos de Riscos Proporcionais
11.
Cerebellum ; 16(4): 840-851, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28456899

RESUMO

Friedreich's ataxia is an inherited neurological disorder characterised by mitochondrial dysfunction and increased susceptibility to oxidative stress. At present, no therapy has been shown to reduce disease progression. Strategies being trialled to treat Friedreich's ataxia include drugs that improve mitochondrial function and reduce oxidative injury. In addition, stem cells have been investigated as a potential therapeutic approach. We have used siRNA-induced knockdown of frataxin in SH-SY5Y cells as an in vitro cellular model for Friedreich's ataxia. Knockdown of frataxin protein expression to levels detected in patients with the disorder was achieved, leading to decreased cellular viability, increased susceptibility to hydrogen peroxide-induced oxidative stress, dysregulation of key anti-oxidant molecules and deficiencies in both cell proliferation and differentiation. Bone marrow stem cells are being investigated extensively as potential treatments for a wide range of neurological disorders, including Friedreich's ataxia. The potential neuroprotective effects of bone marrow-derived mesenchymal stem cells were therefore studied using our frataxin-deficient cell model. Soluble factors secreted by mesenchymal stem cells protected against cellular changes induced by frataxin deficiency, leading to restoration in frataxin levels and anti-oxidant defences, improved survival against oxidative stress and stimulated both cell proliferation and differentiation down the Schwann cell lineage. The demonstration that mesenchymal stem cell-derived factors can restore cellular homeostasis and function to frataxin-deficient cells further suggests that they may have potential therapeutic benefits for patients with Friedreich's ataxia.


Assuntos
Ataxia de Friedreich/metabolismo , Proteínas de Ligação ao Ferro/metabolismo , Células-Tronco Mesenquimais/metabolismo , Diferenciação Celular/fisiologia , Linhagem Celular Tumoral , Proliferação de Células/fisiologia , Sobrevivência Celular/fisiologia , Fêmur , Técnicas de Silenciamento de Genes , Homeostase/fisiologia , Humanos , Peróxido de Hidrogênio/metabolismo , Proteínas de Ligação ao Ferro/genética , Óxido Nítrico/metabolismo , Estresse Oxidativo/fisiologia , RNA Interferente Pequeno , Células de Schwann/metabolismo , Frataxina
12.
J Neurosci Res ; 93(6): 882-92, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25639260

RESUMO

Axonal injury is often characterized by axonal transport defects and abnormal accumulation of intra-axonal components. Nitric oxide (NO) has a key role in mediating inflammatory axonopathy in many neurodegenerative diseases, but little is known about how nitrosative/oxidative stress affects axonal transport or whether reductions in kinesin superfamily protein (KIF) expression correlate with axon pathology. KIFs are molecular motors that have a key role in axonal and dendritic transport, and impairment of these mechanisms has been associated with a number of neurological disorders. This study shows that rat cortical neurons exposed to NO display both a time-dependent decrease in KIF gene/protein expression and neurofilament phosphorylation in addition to a reduction in axonal length and neuronal survival. Because mesenchymal stem cells (MSCs) represent a promising therapeutic candidate for neuronal/axonal repair, this study analyzes the capacity of MSCs to protect neurons and axonal transport mechanisms from NO damage. Results show that coculture of MSCs with NO-exposed neurons results in the preservation of KIF expression, axonal length, and neuronal survival. Altogether, these results suggest a potential mechanism involved in the disruption of axonal transport and abnormal accumulation of proteins in axons during nitrosative insult. We hypothesize that impaired axonal transport contributes, per se, to progression of injury and provide further evidence of the therapeutic potential of MSCs for neurodegenerative disorders.


Assuntos
Axônios/patologia , Sequestradores de Radicais Livres/toxicidade , Regulação da Expressão Gênica/efeitos dos fármacos , Cinesinas/metabolismo , Neurônios/efeitos dos fármacos , Óxido Nítrico/toxicidade , Análise de Variância , Animais , Antígenos CD/metabolismo , Axônios/efeitos dos fármacos , Células da Medula Óssea/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Córtex Cerebral/citologia , Técnicas de Cocultura , Embrião de Mamíferos , Humanos , Cinesinas/genética , Proteínas de Neurofilamentos/metabolismo , Ratos , Fatores de Tempo
13.
Lancet ; 382(9899): 1204-13, 2013 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-24095194

RESUMO

Multiple sclerosis is a major cause of neurological disability, and particularly occurs in young adults. It is characterised by conspicuous patches of damage throughout the brain and spinal cord, with loss of myelin and myelinating cells (oligodendrocytes), and damage to neurons and axons. Multiple sclerosis is incurable, but stem-cell therapy might offer valuable therapeutic potential. Efforts to develop stem-cell therapies for multiple sclerosis have been conventionally built on the principle of direct implantation of cells to replace oligodendrocytes, and therefore to regenerate myelin. Recent progress in understanding of disease processes in multiple sclerosis include observations that spontaneous myelin repair is far more widespread and successful than was previously believed, that loss of axons and neurons is more closely associated with progressive disability than is myelin loss, and that damage occurs diffusely throughout the CNS in grey and white matter, not just in discrete, isolated patches or lesions. These findings have introduced new and serious challenges that stem-cell therapy needs to overcome; the practical challenges to achieve cell replacement alone are difficult enough, but, to be useful, cell therapy for multiple sclerosis must achieve substantially more than the replacement of lost oligodendrocytes. However, parallel advances in understanding of the reparative properties of stem cells--including their distinct immunomodulatory and neuroprotective properties, interactions with resident or tissue-based stem cells, cell fusion, and neurotrophin elaboration--offer renewed hope for development of cell-based therapies. Additionally, these advances suggest avenues for translation of this approach not only for multiple sclerosis, but also for other common neurological and neurodegenerative diseases.


Assuntos
Esclerose Múltipla/terapia , Oligodendroglia/patologia , Transplante de Células-Tronco/métodos , Adulto , Axônios/fisiologia , Células da Medula Óssea/fisiologia , Transplante de Medula Óssea/métodos , Diferenciação Celular , Gliose/terapia , Humanos , Terapia de Imunossupressão/métodos , Transplante de Células-Tronco Mesenquimais/métodos , Esclerose Múltipla/patologia , Bainha de Mielina/fisiologia , Regeneração Nervosa/fisiologia
14.
Acta Neuropathol ; 128(5): 629-38, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24899142

RESUMO

Adult stem cell populations, notably those which reside in the bone marrow, have been shown to contribute to several neuronal cell types in the rodent and human brain. The observation that circulating bone marrow cells can migrate into the central nervous system and fuse with, in particular, cerebellar Purkinje cells has suggested, at least in part, a potential mechanism behind this process. Experimentally, the incidence of cell fusion in the brain is enhanced with age, radiation exposure, inflammation, chemotherapeutic drugs and even selective damage to the neurons themselves. The presence of cell fusion, shown by detection of increased bi-nucleated neurons, has also been described in a variety of human central nervous system diseases, including both multiple sclerosis and Alzheimer's disease. Accumulating evidence is therefore raising new questions into the biological significance of cell fusion, with the possibility that it represents an important means of cell-mediated neuroprotection or rescue of highly complex neurons that cannot be replaced in adult life. Here, we discuss the evidence behind this phenomenon in the rodent and human brain, with a focus on the subsequent research investigating the physiological mechanisms of cell fusion underlying this process. We also highlight how these studies offer new insights into endogenous neuronal repair, opening new exciting avenues for potential therapeutic interventions against neurodegeneration and brain injury.


Assuntos
Células-Tronco Adultas/fisiologia , Encéfalo/citologia , Fusão Celular , Neurônios/fisiologia , Animais , Encéfalo/fisiologia , Humanos
15.
Mult Scler ; 20(6): 651-9, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24067896

RESUMO

BACKGROUND: Peroxisomes are organelles in eukaryotic cells with multiple functions including the detoxification of reactive oxygen species, plasmalogen synthesis and ß-oxidation of fatty acids. Recent evidence has implicated peroxisomal dysfunction in models of multiple sclerosis (MS) disease progression. OBJECTIVES: Our aims were to determine whether there are changes in peroxisomes in MS grey matter (GM) compared to control GM. METHODS: We analysed cases of MS and control GM immunocytochemically to assess peroxisomal membrane protein (PMP70) and neuronal proteins. We examined the expression of ABCD3 (the gene that encodes PMP70) in MS and control GM. Analyses of very long chain fatty acid (VLCFA) levels in GM were performed. RESULTS: PMP70 immunolabelling of neuronal somata was significantly lower in MS GM compared to control. Calibration of ABCD3 gene expression with reference to glyceraldehyde 3-phsophate dehydrogenase (GAPDH) revealed overall decreases in expression in MS compared to controls. Mean PMP70 counts in involved MS GM negatively correlated to disease duration. Elevations in C26:0 (hexacosanoic acid) were found in MS GM. CONCLUSIONS: Collectively, these observations provide evidence that there is an overall reduction in peroxisomal gene expression and peroxisomal proteins in GM neurons in MS. Changes in peroxisomal function may contribute to neuronal dysfunction and degeneration in MS.


Assuntos
Substância Cinzenta/patologia , Proteínas de Membrana/metabolismo , Esclerose Múltipla/patologia , Neurônios/patologia , Peroxissomos/patologia , Transportadores de Cassetes de Ligação de ATP/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Expressão Gênica/fisiologia , Substância Cinzenta/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Neurônios/metabolismo
16.
J Neurol Neurosurg Psychiatry ; 84(10): 1100-6, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23418213

RESUMO

Primary progressive multiple sclerosis (MS) has long been recognised as presenting great difficulties to our management of what is increasingly a treatable neurological disease. Here we review some basic and clinical aspects of primary progressive MS, and describe how the disorder in fact offers powerful insights and opportunities for better understanding multiple sclerosis, and from a practical perspective an invaluable clinical substrate for studying and treating progressive disability in MS. Difficult hurdles remain, however, and these too are reviewed.


Assuntos
Esclerose Múltipla Crônica Progressiva/terapia , Encéfalo/patologia , Diagnóstico Diferencial , Avaliação da Deficiência , Previsões , Humanos , Imageamento por Ressonância Magnética , Esclerose Múltipla Crônica Progressiva/diagnóstico , Esclerose Múltipla Crônica Progressiva/patologia , Esclerose Múltipla Recidivante-Remitente/diagnóstico , Esclerose Múltipla Recidivante-Remitente/patologia , Esclerose Múltipla Recidivante-Remitente/terapia , Fatores de Crescimento Neural/uso terapêutico , Valor Preditivo dos Testes , Prognóstico , Transplante de Células-Tronco
17.
Mult Scler ; 19(2): 153-61, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22723571

RESUMO

BACKGROUND: Axonal loss and grey matter neuronal injury are pathological processes that contribute to disease progression in multiple sclerosis (MS). Axon damage has been associated with changes in the phosphorylation state of neurofilaments and the presence of axonal spheroids. Perikaryal accumulation of abnormally phosphorylated neurofilament proteins has been reported in some neurodegenerative diseases. OBJECTIVES: The objective of this article is to determine whether abnormally phosphorylated neurofilament accumulates in neuronal perikarya in demyelinated MS cortex. METHODS: We used an antibody to hyperphosphorylated neurofilament-H (SMI-34) to assess the level and distribution of this antigen in paraffin sections of cerebral cortex from cases of neuropathologically confirmed MS and controls. We also examined the relationship of neurofilament phosphorylation to cortical demyelination. RESULTS: The number of SMI-34-positive neuronal somata was significantly higher in the MS cortex than the control cortex. As a proportion of the total number of neurons present (i.e. taking account of neuronal loss), the proportion of SMI-34-positive neurons was also significantly higher in the demyelinated and non-demyelinated MS cortex than the control cortex. CONCLUSIONS: MS is associated with the widespread accumulation of hyperphosphorylated neurofilament protein in neuronal somata, with the most marked accumulation in regions of cortical demyelination. This aberrant localisation of hyperphosphorylated neurofilament protein may contribute to neuronal dysfunction and degeneration in MS patients.


Assuntos
Córtex Cerebral/metabolismo , Esclerose Múltipla/metabolismo , Doenças Neurodegenerativas/patologia , Proteínas de Neurofilamentos/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Axônios/patologia , Western Blotting , Córtex Cerebral/patologia , Feminino , Humanos , Técnicas Imunoenzimáticas , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/patologia , Proteínas de Neurofilamentos/imunologia , Neurônios/patologia , Inclusão em Parafina , Fosforilação , Bancos de Tecidos
18.
Brain ; 135(Pt 10): 2962-72, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22975392

RESUMO

A major conceptual consideration in both endogenous and therapeutic central nervous system repair is how damaged (or senescent) neurons, given their often enormously complex and extensive network of connections, can possibly be replaced. The recent observation of fusion of circulating bone marrow cells with, in particular, cerebellar Purkinje cells, as well as the subsequent formation of stable heterokaryons, offers a tantalizing potential solution to this difficulty. Here, we have explored Purkinje cell fusion and heterokaryon formation in the human brain and the influence of central nervous system inflammation. We analysed post-mortem cerebellum tissue from patients who had multiple sclerosis and from appropriate controls. Purkinje cells were analysed for heterokaryon formation using immunohistochemistry techniques and chromosome composition using fluorescence in situ hybridization. For the first time in humans we show a disease-related increase in Purkinje cell fusion and heterokaryon formation. We have shown that heterokaryon formation takes place in control subjects, and that the frequency of this event is considerably increased in patients with multiple sclerosis, the prototypical inflammatory brain disease, with ~0.4% of Purkinje cells being binucleate heterokaryons. No mononucleate polyploid Purkinje cell heterokaryons were found. The observation that heterokaryon formation in the cerebellum occurs as part of the central nervous system inflammatory reaction suggests a potential mechanism of neural repair. It also suggests an exciting new avenue for therapeutic intervention, as enhancement or manipulation of fusion events may have a therapeutic role in cellular protection in multiple sclerosis.


Assuntos
Fusão Celular , Cerebelo/patologia , Esclerose Múltipla/patologia , Células de Purkinje/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Núcleo Celular/genética , Núcleo Celular/patologia , Sistema Nervoso Central/patologia , Feminino , Humanos , Hibridização in Situ Fluorescente , Inflamação/genética , Inflamação/patologia , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/genética
19.
J Neuroinflammation ; 9: 63, 2012 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-22480361

RESUMO

BACKGROUND: Inflammation is known to play a pivotal role in mediating neuronal damage and axonal injury in a variety of neurodegenerative disorders. Among the range of inflammatory mediators, nitric oxide and hydrogen peroxide are potent neurotoxic agents. Recent evidence has suggested that oligodendrocyte peroxisomes may play an important role in protecting neurons from inflammatory damage. METHODS: To assess the influence of peroxisomal activation on nitric oxide mediated neurotoxicity, we investigated the effects of the peroxisomal proliferator activated receptor (PPAR) gamma agonist, pioglitazone in primary cortical neurons that were either exposed to a nitric oxide donor or co-cultured with activated microglia. RESULTS: Pioglitazone protected neurons and axons against both nitric-oxide donor-induced and microglia-derived nitric oxide-induced toxicity. Moreover, cortical neurons treated with this compound showed a significant increase in the protein and gene expression of PPAR-gamma, which was associated with a concomitant increase in the enzymatic activity of catalase. In addition, the protection of neurons and axons against hydrogen peroxide-induced toxicity afforded by pioglitazone appeared to be dependent on catalase. CONCLUSIONS: Collectively, these observations provide evidence that modulation of PPAR-gamma activity and peroxisomal function by pioglitazone attenuates both NO and hydrogen peroxide-mediated neuronal and axonal damage suggesting a new therapeutic approach to protect against neurodegenerative changes associated with neuroinflammation.


Assuntos
Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/patologia , Mediadores da Inflamação/antagonistas & inibidores , Fármacos Neuroprotetores/farmacologia , PPAR gama/agonistas , Peroxissomos/efeitos dos fármacos , Tiazolidinedionas/farmacologia , Animais , Animais Recém-Nascidos , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Córtex Cerebral/metabolismo , Técnicas de Cocultura , Mediadores da Inflamação/fisiologia , Microglia/efeitos dos fármacos , Microglia/metabolismo , Microglia/patologia , PPAR gama/metabolismo , Peroxissomos/patologia , Pioglitazona , Ratos
20.
Cerebellum ; 11(4): 861-71, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22826109

RESUMO

Friedreich's ataxia (FRDA) is a progressive neurodegenerative disorder which is, at present, incurable. Oxidative damage and inhibition of mitochondrial function are key determinants of cellular damage in FRDA, since there is greater sensitivity to oxidative stress in cells with frataxin deficiency. In addition, frataxin-deficient cells have an impaired ability to recruit antioxidant defences against endogenous oxidative stress. We have recently shown that factors derived from bone marrow-derived mesenchymal stem cells (MSCs) increase hydrogen peroxide scavenging enzymes and offer protection against hydrogen peroxide-mediated injury in cells derived from patients with FRDA. Here we extend these studies and have performed a series of experiments showing that expression of superoxide dismutase (1 and 2) enzymes is reduced in FRDA cells but can be restored by treatment with conditioned medium from human MSCs. Furthermore, we have demonstrated that exposure to factors secreted by MSCs increases resistance to nitric oxide-induced oxidative stress in FRDA fibroblasts through, at least in part, restoring the expression of the superoxide dismuting enzymes and via modulation of PI(3) kinase/Akt pathways. These findings suggest that MSCs secrete factors that improve the cellular homeostasis of cells derived from FRDA patients and provide suitable support for their enhanced survival. This study further suggests the potential therapeutic use of MSCs in patients with FRDA.


Assuntos
Ataxia de Friedreich/metabolismo , Proteínas de Ligação ao Ferro/metabolismo , Células-Tronco Mesenquimais/metabolismo , Células Cultivadas , Meios de Cultivo Condicionados , Fibroblastos/metabolismo , Humanos , Peróxido de Hidrogênio/metabolismo , Ferro/metabolismo , Células-Tronco Mesenquimais/citologia , Estresse Oxidativo/fisiologia , Frataxina
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