Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 39
Filtrar
1.
Vector Borne Zoonotic Dis ; 22(4): 209-216, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35446170

RESUMO

Odocoileus virginianus (white-tailed deer) is the primary host of adult Ixodes scapularis (deer tick). Most of the research into I. scapularis has been geographically restricted to the northeastern United States, with limited interest in Oklahoma until recently as the I. scapularis populations spread due to climate change. Ticks serve as a vector for pathogenic bacteria, protozoans, and viruses that pose a significant human health risk. To date, there has been limited research to determine what potential tick-borne pathogens are present in I. scapularis in central Oklahoma. Using a one-step multiplex real-time reverse transcription-PCR, I. scapularis collected from white-tailed deer was screened for Anaplasma phagocytophilum, Borrelia burgdorferi, Borrelia miyamotoi, Babesia microti, and deer tick virus (DTV). Ticks (n = 394) were pooled by gender and life stage into 117 samples. Three pooled samples were positive for B. miyamotoi and five pooled samples were positive for DTV. This represents a minimum infection rate of 0.8% and 1.2%, respectively. A. phagocytophilum, B. burgdorferi, and B. microti were not detected in any samples. This is the first report of B. miyamotoi and DTV detection in Oklahoma I. scapularis ticks. This demonstrates that I. scapularis pathogens are present in Oklahoma and that further surveillance of I. scapularis is warranted.


Assuntos
Borrelia burgdorferi , Borrelia , Cervos , Vírus da Encefalite Transmitidos por Carrapatos , Ixodes , Animais , Borrelia/genética , Vírus da Encefalite Transmitidos por Carrapatos/genética , Ixodes/microbiologia , Oklahoma/epidemiologia
2.
J Clin Med ; 7(2)2018 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-29461488

RESUMO

OBJECTIVES: Evidence of mitochondrial respiratory chain (MRC) dysfunction and oxidative stress has been implicated in the pathophysiology of multiple sclerosis (MS). However, at present, there is no reliable low invasive surrogate available to evaluate mitochondrial function in these patients. In view of the particular sensitivity of MRC complex IV to oxidative stress, the aim of this study was to assess blood mononuclear cell (BMNC) MRC complex IV activity in MS patients and compare these results to age matched controls and MS patients on ß-interferon treatment. METHODS: Spectrophotometric enzyme assay was employed to measure MRC complex IV activity in blood mononuclear cell obtained multiple sclerosis patients and aged matched controls. RESULTS: MRC Complex IV activity was found to be significantly decreased (p < 0.05) in MS patients (2.1 ± 0.8 k/nmol × 10-3; mean ± SD] when compared to the controls (7.2 ± 2.3 k/nmol × 10-3). Complex IV activity in MS patients on ß-interferon (4.9 ± 1.5 k/nmol × 10-3) was not found to be significantly different from that of the controls. CONCLUSIONS: This study has indicated evidence of peripheral MRC complex IV deficiency in MS patients and has highlighted the potential utility of BMNCs as a potential means to evaluate mitochondrial function in this disorder. Furthermore, the reported improvement of complex IV activity may provide novel insights into the mode(s) of action of ß-interferon.

3.
Mol Syndromol ; 5(3-4): 147-55, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25126047

RESUMO

Coenzyme Q10 (CoQ10) deficiency appears to have a particularly heterogeneous clinical presentation. However, there appear to be 5 recognisable clinical phenotypes: encephalomyopathy, severe infantile multisystemic disease, nephropathy, cerebellar ataxia, and isolated myopathy. However, although useful, clinical symptoms alone are insufficient for the definitive diagnosis of CoQ10 deficiency which relies upon biochemical assessment of tissue CoQ10 status. In this article, we review the biochemical methods used in the diagnosis of human CoQ10 deficiency and indicate the most appropriate tissues for this evaluation.

4.
Brain ; 137(Pt 1): 44-56, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24253200

RESUMO

Childhood onset motor neuron diseases or neuronopathies are a clinically heterogeneous group of disorders. A particularly severe subgroup first described in 1894, and subsequently called Brown-Vialetto-Van Laere syndrome, is characterized by progressive pontobulbar palsy, sensorineural hearing loss and respiratory insufficiency. There has been no treatment for this progressive neurodegenerative disorder, which leads to respiratory failure and usually death during childhood. We recently reported the identification of SLC52A2, encoding riboflavin transporter RFVT2, as a new causative gene for Brown-Vialetto-Van Laere syndrome. We used both exome and Sanger sequencing to identify SLC52A2 mutations in patients presenting with cranial neuropathies and sensorimotor neuropathy with or without respiratory insufficiency. We undertook clinical, neurophysiological and biochemical characterization of patients with mutations in SLC52A2, functionally analysed the most prevalent mutations and initiated a regimen of high-dose oral riboflavin. We identified 18 patients from 13 families with compound heterozygous or homozygous mutations in SLC52A2. Affected individuals share a core phenotype of rapidly progressive axonal sensorimotor neuropathy (manifesting with sensory ataxia, severe weakness of the upper limbs and axial muscles with distinctly preserved strength of the lower limbs), hearing loss, optic atrophy and respiratory insufficiency. We demonstrate that SLC52A2 mutations cause reduced riboflavin uptake and reduced riboflavin transporter protein expression, and we report the response to high-dose oral riboflavin therapy in patients with SLC52A2 mutations, including significant and sustained clinical and biochemical improvements in two patients and preliminary clinical response data in 13 patients with associated biochemical improvements in 10 patients. The clinical and biochemical responses of this SLC52A2-specific cohort suggest that riboflavin supplementation can ameliorate the progression of this neurodegenerative condition, particularly when initiated soon after the onset of symptoms.


Assuntos
Paralisia Bulbar Progressiva/genética , Perda Auditiva Neurossensorial/genética , Mutação/genética , Receptores Acoplados a Proteínas G/genética , Adolescente , Encéfalo/patologia , Paralisia Bulbar Progressiva/tratamento farmacológico , Carnitina/análogos & derivados , Carnitina/sangue , Criança , Pré-Escolar , Exoma/genética , Feminino , Genótipo , Perda Auditiva Neurossensorial/tratamento farmacológico , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Análise em Microsséries , Doença dos Neurônios Motores/fisiopatologia , Exame Neurológico , Linhagem , RNA/biossíntese , RNA/genética , Riboflavina/uso terapêutico , Análise de Sequência de DNA , Nervo Sural/patologia , Vitaminas/uso terapêutico , Adulto Jovem
5.
J Neurol Neurosurg Psychiatry ; 85(5): 486-92, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24198383

RESUMO

OBJECTIVE: Charcot-Marie Tooth disease (CMT) forms a clinically and genetically heterogeneous group of disorders. Although a number of disease genes have been identified for CMT, the gene discovery for some complex form of CMT has lagged behind. The association of neuropathy and optic atrophy (also known as CMT type 6) has been described with autosomaldominant, recessive and X-linked modes of inheritance. Mutations in Mitofusin 2 have been found to cause dominant forms of CMT6. Phosphoribosylpyrophosphate synthetase-I mutations cause X-linked CMT6, but until now, mutations in the recessive forms of disease have never been identified. METHODS: We here describe a family with three affected individuals who inherited in an autosomal recessive fashion a childhood onset neuropathy and optic atrophy. Using homozygosity mapping in the family and exome sequencing in two affected individuals we identified a novel protein-truncating mutation in the C12orf65 gene, which encodes for a protein involved in mitochondrial translation. Using a variety of methods we investigated the possibility of mitochondrial impairment in the patients cell lines. RESULTS: We described a large consanguineous family with neuropathy and optic atrophy carrying a loss of function mutation in the C12orf65 gene. We report mitochondrial impairment in the patients cell lines, followed by multiple lines of evidence which include decrease of complex V activity and stability (blue native gel assay), decrease in mitochondrial respiration rate and reduction of mitochondrial membrane potential. CONCLUSIONS: This work describes a mutation in the C12orf65 gene that causes recessive form of CMT6 and confirms the role of mitochondrial dysfunction in this complex axonal neuropathy.


Assuntos
Neuropatia Hereditária Motora e Sensorial/complicações , Neuropatia Hereditária Motora e Sensorial/genética , Mutação/genética , Fatores de Terminação de Peptídeos/genética , Adolescente , Adulto , Criança , Estudos de Coortes , Feminino , GTP Fosfo-Hidrolases/genética , Genótipo , Neuropatia Hereditária Motora e Sensorial/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas Mitocondriais/genética , Linhagem , Polimorfismo de Nucleotídeo Único/genética , Ribose-Fosfato Pirofosfoquinase/genética , Adulto Jovem
6.
Neurochem Int ; 63(8): 750-5, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24140430

RESUMO

Deficiency of 5-methyltetrahydrofolate (5-MTHF) in cerebrospinal fluid (CSF) is associated with a number of neurometabolic conditions including mitochondrial electron transport chain defects. Whilst failure of the active transport of 5-methyltetrahydrofolate (5-MTHF) into the CSF compartment has been proposed as a potential mechanism responsible for the 5-MTHF deficiency seen in mitochondrial disorders, it is becoming increasingly clear that other mechanisms are involved. Here, we have considered the role of oxidative stress as a contributing mechanism. Concerning, ascorbic acid (AA), we have established a CSF reference range (103-303µM) and demonstrated a significant positive correlation between 5-MTHF and AA. Furthermore, CSF itself was also shown to convey antioxidant properties towards 5-MTHF. However, this protection could be overcome by the introduction of a hydroxyl radical generating system. Using a neuronal model system, inhibition of mitochondrial complex I, by 58%, was associated with a 23% increase in superoxide generation and a significantly increased loss of 5-MTHF from the extracellular medium. Addition of AA (150µM) was able to prevent this increased 5-MTHF catabolism. We conclude that increased generation of reactive oxygen species and/or loss of CSF antioxidants are also factors to consider with regard to the development of a central 5-MTHF deficiency. Co-supplementation of AA together with appropriate folate replacement may be of therapeutic benefit.


Assuntos
Ácido Ascórbico/líquido cefalorraquidiano , Ácido Fólico/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Tetra-Hidrofolatos/líquido cefalorraquidiano , Adolescente , Adulto , Linhagem Celular Tumoral , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Mitocôndrias/metabolismo , Adulto Jovem
7.
JAMA Neurol ; 70(12): 1556-61, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24100867

RESUMO

IMPORTANCE: Isolated cytochrome-c oxidase (COX) deficiency is one of the most frequent respiratory chain defects seen in human mitochondrial disease. Typically, patients present with severe neonatal multisystem disease and have an early fatal outcome. We describe an adult patient with isolated COX deficiency associated with a relatively mild clinical phenotype comprising myopathy; demyelinating neuropathy; premature ovarian failure; short stature; hearing loss; pigmentary maculopathy; and renal tubular dysfunction. OBSERVATIONS: Whole-exome sequencing detected 1 known pathogenic and 1 novel COX10 mutation: c.1007A>T; p.Asp336Val, previously associated with fatal infantile COX deficiency, and c.1015C>T; p.Arg339Trp. Muscle COX holoenzyme and subassemblies were undetectable on immunoblots of blue-native gels, whereas denaturing gels and immunocytochemistry showed reduced core subunit MTCO1. Heme absorption spectra revealed low heme aa3 compatible with heme A:farnesyltransferase deficiency due to COX10 dysfunction. Both mutations demonstrated respiratory deficiency in yeast, confirming pathogenicity. A COX10 protein model was used to predict the structural consequences of the novel Arg339Trp and all previously reported substitutions. CONCLUSIONS AND RELEVANCE: These findings establish that COX10 mutations cause adult mitochondrial disease. Nuclear modifiers, epigenetic phenomenon, and/or environmental factors may influence the disease phenotype caused by reduced COX activity and contribute to the variable clinical severity related to COX10 dysfunction.


Assuntos
Alquil e Aril Transferases/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Proteínas de Membrana/genética , Doenças Mitocondriais/genética , Mutação/genética , Adulto , Feminino , Humanos , Estudos Longitudinais , Doenças Mitocondriais/patologia , Doenças Mitocondriais/fisiopatologia , Modelos Moleculares , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Músculo Esquelético/ultraestrutura , Nervo Sural/patologia , Nervo Sural/ultraestrutura , Leveduras/genética
8.
Biol Open ; 2(8): 761-70, 2013 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-23951401

RESUMO

Transcription factor Nrf2 and its repressor Keap1 regulate a network of cytoprotective genes involving more than 1% of the genome, their best known targets being drug-metabolizing and antioxidant genes. Here we demonstrate a novel role for this pathway in directly regulating mitochondrial bioenergetics in murine neurons and embryonic fibroblasts. Loss of Nrf2 leads to mitochondrial depolarisation, decreased ATP levels and impaired respiration, whereas genetic activation of Nrf2 increases the mitochondrial membrane potential and ATP levels, the rate of respiration and the efficiency of oxidative phosphorylation. We further show that Nrf2-deficient cells have increased production of ATP in glycolysis, which is then used by the F1Fo-ATPase for maintenance of the mitochondrial membrane potential. While the levels and in vitro activities of the respiratory complexes are unaffected by Nrf2 deletion, their activities in isolated mitochondria and intact live cells are substantially impaired. In addition, the rate of regeneration of NADH after inhibition of respiration is much slower in Nrf2-knockout cells than in their wild-type counterparts. Taken together, these results show that Nrf2 directly regulates cellular energy metabolism through modulating the availability of substrates for mitochondrial respiration. Our findings highlight the importance of efficient energy metabolism in Nrf2-mediated cytoprotection.

9.
Orphanet J Rare Dis ; 8: 96, 2013 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-23829769

RESUMO

BACKGROUND: SURF1 deficiency, a monogenic mitochondrial disorder, is the most frequent cause of cytochrome c oxidase (COX) deficient Leigh syndrome (LS). We report the first natural history study of SURF1 deficiency. METHODS: We conducted a multi-centre case notes review of 44 SURF1-deficient patients from ten different UK centres and two Australian centres. Survival data for LRPPRC-deficient LS and nuclear-encoded complex I-deficient LS patients were obtained from previous publications. The survival of SURF1-deficient patients was compared with these two groups using Kaplan-Meier survival analysis and logrank test. RESULTS: The majority of patients (32/44, 73%) presented in infancy (median 9.5 months). Frequent symptoms were poor weight gain (95%, median age 10 months), hypotonia (93%, median age 14 months), poor feeding/vomiting (89%, median age 10 months), developmental delay (88%, median age 14 months), developmental regression (71%, median age 19 months), movement disorder (52%, median age 24 months), oculomotor involvement (52%, median age 29 months) and central respiratory failure (78%, median age 31 months). Hypertrichosis (41%), optic atrophy (23%), encephalopathy (20%), seizures (14%) and cardiomyopathy (2%) were observed less frequently. CONCLUSIONS: SURF1-deficient patients have a homogeneous clinical and biochemical phenotype. Early recognition is essential to expedite diagnosis and enable prenatal diagnosis.


Assuntos
Doença de Leigh/metabolismo , Doença de Leigh/patologia , Proteínas de Membrana/deficiência , Proteínas Mitocondriais/deficiência , Adolescente , Adulto , Criança , Pré-Escolar , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Feminino , Humanos , Lactente , Recém-Nascido , Doença de Leigh/genética , Masculino , Adulto Jovem
10.
Hum Mol Genet ; 22(19): 3819-27, 2013 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-23727839

RESUMO

Coenzyme Q10 (CoQ10) is essential for the energy production of the cells and as an electron transporter in the mitochondrial respiratory chain. CoQ10 links the mitochondrial fatty acid ß-oxidation to the respiratory chain by accepting electrons from electron transfer flavoprotein-ubiquinone oxidoreductase (ETF-QO). Recently, it was shown that a group of patients with the riboflavin responsive form of multiple acyl-CoA dehydrogenation deficiency (RR-MADD) carrying inherited amino acid variations in ETF-QO also had secondary CoQ10 deficiency with beneficial effects of CoQ10 treatment, thus adding RR-MADD to an increasing number of diseases involving secondary CoQ10 deficiency. In this study, we show that moderately decreased CoQ10 levels in fibroblasts from six unrelated RR-MADD patients were associated with increased levels of mitochondrial reactive oxygen species (ROS). Treatment with CoQ10, but not with riboflavin, could normalize the CoQ10 level and decrease the level of ROS in the patient cells. Additionally, riboflavin-depleted control fibroblasts showed moderate CoQ10 deficiency, but not increased mitochondrial ROS, indicating that variant ETF-QO proteins and not CoQ10 deficiency are the causes of mitochondrial ROS production in the patient cells. Accordingly, the corresponding variant Rhodobacter sphaeroides ETF-QO proteins, when overexpressed in vitro, bind a CoQ10 pseudosubstrate, Q10Br, less tightly than the wild-type ETF-QO protein, suggesting that molecular oxygen can get access to the electrons in the misfolded ETF-QO protein, thereby generating superoxide and oxidative stress, which can be reversed by CoQ10 treatment.


Assuntos
Flavoproteínas Transferidoras de Elétrons/genética , Flavoproteínas Transferidoras de Elétrons/metabolismo , Fibroblastos/metabolismo , Proteínas Ferro-Enxofre/genética , Proteínas Ferro-Enxofre/metabolismo , Deficiência Múltipla de Acil Coenzima A Desidrogenase/metabolismo , Estresse Oxidativo , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/genética , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/metabolismo , Ubiquinona/análogos & derivados , Acil Coenzima A/metabolismo , Ataxia/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Células Cultivadas , Variação Genética , Humanos , Mitocôndrias/metabolismo , Doenças Mitocondriais/metabolismo , Deficiência Múltipla de Acil Coenzima A Desidrogenase/complicações , Deficiência Múltipla de Acil Coenzima A Desidrogenase/tratamento farmacológico , Debilidade Muscular/metabolismo , Oxirredução/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Rhodobacter sphaeroides/genética , Rhodobacter sphaeroides/metabolismo , Riboflavina/metabolismo , Riboflavina/farmacologia , Ubiquinona/deficiência , Ubiquinona/metabolismo , Ubiquinona/farmacologia , Ubiquinona/uso terapêutico
11.
Mitochondrion ; 13(4): 337-41, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23583954

RESUMO

We evaluated coenzyme Q10 (CoQ) levels in patients studied under suspicion of mitochondrial DNA depletion syndromes (MDS) (n=39). CoQ levels were quantified by HPLC, and the percentage of mtDNA depletion by quantitative real-time PCR. A high percentage of MDS patients presented with CoQ deficiency as compared to other mitochondrial patients (Mann-Whitney-U test: p=0.001). Our findings suggest that MDS are frequently associated with CoQ deficiency, as a possible secondary consequence of disease pathophysiology. Assessment of muscle CoQ status seems advisable in MDS patients since the possibility of CoQ supplementation may then be considered as a candidate therapy.


Assuntos
Ataxia/epidemiologia , Erros Inatos do Metabolismo/complicações , Doenças Mitocondriais/complicações , Doenças Mitocondriais/epidemiologia , Miopatias Mitocondriais/complicações , Debilidade Muscular/epidemiologia , Doenças Musculares/complicações , Ubiquinona/deficiência , Adolescente , Ataxia/diagnóstico , Criança , Pré-Escolar , Cromatografia Líquida de Alta Pressão , DNA Mitocondrial/análise , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Doenças Mitocondriais/diagnóstico , Debilidade Muscular/diagnóstico , Reação em Cadeia da Polimerase em Tempo Real , Ubiquinona/análogos & derivados , Ubiquinona/análise , Adulto Jovem
12.
Rapid Commun Mass Spectrom ; 27(9): 924-30, 2013 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-23592193

RESUMO

RATIONALE: Neurological dysfunction is common in primary coenzyme Q10 (2,3-dimethoxy, 5-methyl, 6-polyisoprene parabenzoquinone; CoQ10 ; ubiquinone) deficiencies, the most readily treatable subgroup of mitochondrial disorders. Therapeutic benefit from CoQ10 supplementation has also been noted in other neurodegenerative diseases. CoQ10 can be measured by high-performance liquid chromatography (HPLC) in plasma, muscle or leucocytes; however, there is no reliable method to quantify CoQ10 in cerebrospinal fluid (CSF). Additionally, many methods use CoQ9 , an endogenous ubiquinone in humans, as an internal standard. METHODS: Deuterated CoQ10 (d6 -CoQ10 ) was synthesised by a novel, simple, method. Total CoQ10 was measured by liquid chromatography/tandem mass spectrometry (LC/MS/MS) using d6 -CoQ10 as internal standard and 5 mM methylamine as an ion-pairing reagent. Chromatography was performed using a Hypsersil GOLD C4 column (150 × 3 mm, 3 µm). RESULTS: CoQ10 levels were linear over a concentration range of 0-200 nM (R(2) = 0.9995). The lower limit of detection was 2 nM. The inter-assay coefficient of variation (CV) was 3.6% (10 nM) and 4.3% (20 nM), and intra-assay CV 3.4% (10 nM) and 3.6% (20 nM). Reference ranges were established for CoQ10 in CSF (5.7-8.7 nM; n = 17), fibroblasts (57.0-121.6 pmol/mg; n = 50) and muscle (187.3-430.1 pmol/mg; n = 15). CONCLUSIONS: Use of d6 -CoQ10 internal standard has enabled the development of a sensitive LC/MS/MS method to accurately determine total CoQ10 levels. Clinical applications of CSF CoQ10 determination include identification of patients with cerebral CoQ10 deficiency, and monitoring CSF CoQ10 levels following supplementation.


Assuntos
Fibroblastos/química , Músculo Esquelético/química , Espectrometria de Massas em Tandem/métodos , Ubiquinona/análogos & derivados , Adolescente , Adulto , Células Cultivadas , Criança , Pré-Escolar , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida de Alta Pressão/normas , Deutério/análise , Feminino , Humanos , Lactente , Limite de Detecção , Masculino , Pessoa de Meia-Idade , Oxirredução , Padrões de Referência , Espectrometria de Massas em Tandem/normas , Ubiquinona/análise , Ubiquinona/líquido cefalorraquidiano , Adulto Jovem
13.
Toxicol Mech Methods ; 23(6): 459-63, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23464834

RESUMO

Elevated plasma homocysteine (Hcy) has been detected in patients with various neurodegenerative conditions. Studies on neurones and cerebral tissue have revealed that hyperhomocystinaemia may inhibit mitochondrial electron transport chain (ETC) enzyme activity resulting in neuronal morbidity. As astrocytes convey a protective and supportive role towards neurones, we postulated that Hcy-induced astrocytic ETC inhibition may contribute to neurological dysfunction. In order to investigate this hypothesis, we established a cellular model of hyperhomocystinaemia using primary rat astrocytes. Which were incubated were incubated with 200 µM, 500 µM Hcy and the Hcy metabolite, thiolactone (10 µM). Following 96 h of incubation with 200 µM and 500 µM Hcy, an approximate two-fold (1.11 nmol/mg) and three-fold (1.45 nmol/mg) increase in mitochondrial levels of Hcy, respectively, were detected compared to control levels (0.54 nmol/mg). However, on exposure to Hcy (200 or 500 µM) and Hcy-thiolactone (10 µM), the activities of astrocytic ETC complex I, II-III and IV were found to be comparable to control levels. In addition, the extracellular lactate:pyruvate ratio and the intracellular glutathione status of primary rat astrocytes were not significantly different between Hcy (200 or 500 µM) treated and controls. In conclusion, the results of this study suggest that Hcy induced impairment of astrocytic ETC function may not contribute to the pathophysiology of hyperhomocystinaemia.


Assuntos
Astrócitos/efeitos dos fármacos , Complexo de Proteínas da Cadeia de Transporte de Elétrons/metabolismo , Homocisteína/toxicidade , Hiper-Homocisteinemia/metabolismo , Mitocôndrias/efeitos dos fármacos , Modelos Biológicos , Animais , Animais Recém-Nascidos , Astrócitos/metabolismo , Células Cultivadas , Relação Dose-Resposta a Droga , Glutationa/metabolismo , Homocisteína/metabolismo , Mitocôndrias/metabolismo , Cultura Primária de Células , Ratos , Ratos Sprague-Dawley , Fatores de Tempo
14.
FASEB J ; 27(1): 379-90, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23024373

RESUMO

Low birth weight and accelerated postnatal growth lead to increased risk of cardiovascular disease. We reported previously that rats exposed to a low-protein diet in utero and postnatal catch-up growth (recuperated) develop metabolic dysfunction and have reduced life span. Here we explored the hypothesis that cardiac oxidative and nitrosative stress leading to DNA damage and accelerated cellular aging could contribute to these phenotypes. Recuperated animals had a low birth weight (P<0.001) but caught up in weight to controls during lactation. At weaning, recuperated cardiac tissue had increased (P<0.05) protein nitrotyrosination and DNA single-stranded breaks. This condition was preceded by increased expression of DNA damage repair molecules 8-oxoguanine-DNA-glycosylase-1, nei-endonuclease-VIII-like, X-ray-repair-complementing-defective-repair-1, and Nthl endonuclease III-like-1 on d 3. These differences were maintained on d 22 and became more pronounced in the case of 8-oxoguanine-DNA-glycosylase-1 and nei-endonuclease-VIII-like. This was accompanied by increases in xanthine oxidase (P<0.001) and NADPH oxidase (P<0.05), major sources of reactive oxygen species (ROS). The detrimental effects of increased ROS in recuperated offspring may be exaggerated at 22 d by reductions (P<0.001) in the antioxidant enzymes peroxiredoxin-3 and CuZn-superoxide-dismutase. We conclude that poor fetal nutrition followed by accelerated postnatal growth results in increased cardiac nitrosative and oxidative-stress and DNA damage, which could contribute to age-associated disease risk.


Assuntos
Dano ao DNA , Reparo do DNA , Crescimento , Desnutrição/metabolismo , Miocárdio/metabolismo , Nitrosação , Estresse Oxidativo , Animais , Sequência de Bases , Peso Corporal , Primers do DNA , DNA Mitocondrial/genética , Feminino , Perfilação da Expressão Gênica , Desnutrição/genética , Tamanho do Órgão , Gravidez , Ratos , Ratos Wistar , Telômero
15.
Neurochem Int ; 62(5): 684-94, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23261515

RESUMO

Dopamine is produced first by hydroxylalation of l-tyrosine to l-dihydroxyphenylalanine (l-dopa) and subsequently by the decarboxylation of l-dopa to dopamine catalysed by the enzymes tyrosine hydroxylase and aromatic l-amino acid decarboxylase (AADC) respectively. Reduced glutathione (GSH) acts as a major cellular antioxidant. We have investigated the role of dopamine in the control of GSH homeostasis in brain cells. The SH-SY5Y human neuroblastoma cell line was found to increase intracellular GSH levels in response to 50µM dopamine treatment. Similarly the 1321N1 human astrocytoma cell line was found to increase GSH release in response to 50µM dopamine. The same concentration of l-dopa was also found to increase intracellular GSH in SH-SY5Y cells, however when AADC was inhibited this affect was abolished. Furthermore 1321N1 cells which were found to have almost undetectable levels of AADC activity did not increase GSH release in response to 50µM l-dopa. These results suggest that at these concentrations dopamine has the potential to act as a signal for the upregulation of GSH synthesis within neuronal-like cells and for the increased trafficking of GSH from astrocytes to neurons. This effect could potentially relate to the activation of antioxidant response elements leading to the induction of phase II detoxifying enzymes including those involved in GSH synthesis and release. The inability of l-dopa to produce a similar effect when AADC was inhibited or when AADC activity was absent indicates that these effects are relatively specific to dopamine. Additionally dopamine but not l-dopa treatment led in an increase in complex I activity of the respiratory chain in SH-SY5Y cells which may be related to the effect of dopamine on GSH levels.


Assuntos
Encéfalo/efeitos dos fármacos , Dopamina/farmacologia , Glutationa/metabolismo , Levodopa/farmacologia , Doença de Parkinson/metabolismo , Descarboxilases de Aminoácido-L-Aromático/metabolismo , Encéfalo/citologia , Encéfalo/enzimologia , Encéfalo/metabolismo , Linhagem Celular Tumoral , Humanos , Neurônios/efeitos dos fármacos , Neurônios/enzimologia , Neurônios/metabolismo , Doença de Parkinson/enzimologia
16.
Neurology ; 79(11): 1145-54, 2012 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-22933740

RESUMO

OBJECTIVE: Charcot-Marie-Tooth (CMT) disease is the most common inherited neuromuscular disorder, affecting 1 in 2,500 individuals. Mitochondrial DNA (mtDNA) mutations are not generally considered within the differential diagnosis of patients with uncomplicated inherited neuropathy, despite the essential requirement of ATP for axonal function. We identified the mtDNA mutation m.9185T>C in MT-ATP6, encoding the ATP6 subunit of the mitochondrial ATP synthase (OXPHOS complex V), at homoplasmic levels in a family with mitochondrial disease in whom a severe motor axonal neuropathy was a striking feature. This led us to hypothesize that mutations in the 2 mtDNA complex V subunit encoding genes, MT-ATP6 and MT-ATP8, might be an unrecognized cause of isolated axonal CMT and distal hereditary motor neuropathy (dHMN). METHODS: A total of 442 probands with CMT type 2 (CMT2) (270) and dHMN (172) were screened for MT-ATP6/8 mutations after exclusion of mutations in known CMT2/dHMN genes. Mutation load was quantified using restriction endonuclease analysis. Blue-native gel electrophoresis (BN-PAGE) was performed to analyze the effects of m.9185T>C on complex V structure and function. RESULTS: Three further probands with CMT2 harbored the m.9185T>C mutation. Some relatives had been classified as having dHMN. Patients could be separated into 4 groups according to their mutant m.9185T>C levels. BN-PAGE demonstrated both impaired assembly and reduced activity of the complex V holoenzyme. CONCLUSIONS: We have shown that m.9185T>C in MT-ATP6 causes CMT2 in 1.1% of genetically undefined cases. This has important implications for diagnosis and genetic counseling. Recognition that mutations in MT-ATP6 cause CMT2 enhances current understanding of the pathogenic basis of axonal neuropathy.


Assuntos
Doença de Charcot-Marie-Tooth/genética , DNA Mitocondrial , ATPases Mitocondriais Próton-Translocadoras/genética , Mutação , Adolescente , Adulto , Idoso de 80 Anos ou mais , Doença de Charcot-Marie-Tooth/fisiopatologia , Criança , Feminino , Genótipo , Neuropatia Hereditária Motora e Sensorial/genética , Neuropatia Hereditária Motora e Sensorial/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem
17.
Cell Metab ; 15(3): 361-71, 2012 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-22405071

RESUMO

The citric acid cycle (CAC) metabolite fumarate has been proposed to be cardioprotective; however, its mechanisms of action remain to be determined. To augment cardiac fumarate levels and to assess fumarate's cardioprotective properties, we generated fumarate hydratase (Fh1) cardiac knockout (KO) mice. These fumarate-replete hearts were robustly protected from ischemia-reperfusion injury (I/R). To compensate for the loss of Fh1 activity, KO hearts maintain ATP levels in part by channeling amino acids into the CAC. In addition, by stabilizing the transcriptional regulator Nrf2, Fh1 KO hearts upregulate protective antioxidant response element genes. Supporting the importance of the latter mechanism, clinically relevant doses of dimethylfumarate upregulated Nrf2 and its target genes, hence protecting control hearts, but failed to similarly protect Nrf2-KO hearts in an in vivo model of myocardial infarction. We propose that clinically established fumarate derivatives activate the Nrf2 pathway and are readily testable cytoprotective agents.


Assuntos
Antioxidantes/metabolismo , Fumaratos/uso terapêutico , Fator 2 Relacionado a NF-E2/metabolismo , Animais , Fumarato de Dimetilo , Fumarato Hidratase/deficiência , Fumarato Hidratase/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Modelos Biológicos , Infarto do Miocárdio/genética , Infarto do Miocárdio/prevenção & controle , Fator 2 Relacionado a NF-E2/genética , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
18.
PLoS One ; 6(8): e23182, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21858020

RESUMO

BACKGROUND: Patients with epilepsy often suffer from other important conditions. The existence of such co-morbidities is frequently not recognized and their relationship with epilepsy usually remains unexplained. METHODOLOGY/PRINCIPAL FINDINGS: We describe three patients with common, sporadic, non-syndromic epilepsies in whom large genomic microdeletions were found during a study of genetic susceptibility to epilepsy. We performed detailed gene-driven clinical investigations in each patient. Disruption of the function of genes in the deleted regions can explain co-morbidities in these patients. CONCLUSIONS/SIGNIFICANCE: Co-morbidities in patients with epilepsy can be part of a genomic abnormality even in the absence of (known) congenital malformations or intellectual disabilities. Gene-driven phenotype examination can also reveal clinically significant unsuspected condition.


Assuntos
Deleção Cromossômica , Transtornos Cromossômicos/genética , Epilepsia/genética , Estudos de Associação Genética , Anormalidades Múltiplas/genética , Anormalidades Múltiplas/patologia , Adulto , Transtornos Cromossômicos/epidemiologia , Transtornos Cromossômicos/patologia , Cromossomos Humanos Par 12/genética , Cromossomos Humanos Par 17/genética , Cromossomos Humanos Par 3/genética , Comorbidade , Epilepsia/epidemiologia , Epilepsia/patologia , Feminino , Deleção de Genes , Predisposição Genética para Doença/genética , Humanos , Masculino
19.
J Pediatr ; 158(3): 458-62, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20884007

RESUMO

OBJECTIVE: To investigate whether statin therapy affects coenzyme Q10 (CoQ10) status in children with heterozygous familial hypercholesterolemia (FH). STUDY DESIGN: Samples were obtained at baseline (treatment naïve) and after dose titration with rosuvastatin, aiming for a low-density lipoprotein cholesterol level of 110 mg/dL. Twenty-nine patients were treated with 5, 10, or 20 mg of rosuvastatin for a mean period of 29 weeks. RESULTS: We found a significant (32%) decrease in peripheral blood mononuclear cell (PBMC) CoQ10 level (P = .02), but no change in PBMC adenosine triphosphate synthesis (P = .60). Uncorrected plasma CoQ10 values were decreased significantly, by 45% (P < .01). In contrast, ratios of plasma CoQ10/total cholesterol and CoQ10/low-density lipoprotein cholesterol remained equal during treatment. CONCLUSIONS: In children with FH, rosuvastatin causes a significant decrease in cellular PBMC CoQ10 status but does not affect mitochondrial adenosine triphosphate synthesis in children with FH. Further studies should address whether (rare) side effects of statin therapy could be explained by a deterioration in CoQ10 status.


Assuntos
Trifosfato de Adenosina/biossíntese , Fluorbenzenos/farmacologia , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Hiperlipoproteinemia Tipo II/tratamento farmacológico , Pirimidinas/farmacologia , Sulfonamidas/farmacologia , Ubiquinona/análogos & derivados , Adolescente , Criança , Colesterol/sangue , Relação Dose-Resposta a Droga , Humanos , Leucócitos Mononucleares/metabolismo , Mitocôndrias/metabolismo , Países Baixos , Rosuvastatina Cálcica , Ubiquinona/sangue , Ubiquinona/efeitos dos fármacos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...