RESUMO
Coenzyme Q10 (CoQ10) is an important cofactor and antioxidant for numerous cellular processes, and its deficiency has been linked to human disorders including mitochondrial disease, heart failure, Parkinson's disease, and hypertension. Unfortunately, treatment with exogenous CoQ10 is often ineffective, likely due to its extreme hydrophobicity and high molecular weight. Here, we show that less hydrophobic CoQ species with shorter isoprenoid tails can serve as viable substitutes for CoQ10 in human cells. We demonstrate that CoQ4 can perform multiple functions of CoQ10 in CoQ-deficient cells at markedly lower treatment concentrations, motivating further investigation of CoQ4 as a supplement for CoQ10 deficiencies. In addition, we describe the synthesis and evaluation of an initial set of compounds designed to target CoQ4 selectively to mitochondria using triphenylphosphonium. Our results indicate that select versions of these compounds can successfully be delivered to mitochondria in a cell model and be cleaved to produce CoQ4, laying the groundwork for further development.
Assuntos
Ataxia , Mitocôndrias , Doenças Mitocondriais , Debilidade Muscular , Ubiquinona , Humanos , Mitocôndrias/enzimologia , Doenças Mitocondriais/enzimologia , Doenças Mitocondriais/genética , Debilidade Muscular/enzimologia , Debilidade Muscular/genética , Ubiquinona/análogos & derivados , Ubiquinona/deficiência , Células Hep G2RESUMO
Coenzyme Q10 (CoQ10 ) plays a crucial role in mitochondria as an electron carrier within the mitochondrial respiratory chain (MRC) and is an essential antioxidant. Mutations in genes responsible for CoQ10 biosynthesis (COQ genes) cause primary CoQ10 deficiency, a rare and heterogeneous mitochondrial disorder with no clear genotype-phenotype association, mainly affecting tissues with high-energy demand including brain and skeletal muscle (SkM). Here, we report a four-year-old girl diagnosed with minor mental retardation and lethal rhabdomyolysis harboring a heterozygous mutation (c.483G > C (E161D)) in COQ4. The patient's fibroblasts showed a decrease in [CoQ10 ], CoQ10 biosynthesis, MRC activity affecting complexes I/II + III, and respiration defects. Bona fide induced pluripotent stem cell (iPSCs) lines carrying the COQ4 mutation (CQ4-iPSCs) were generated, characterized and genetically edited using the CRISPR-Cas9 system (CQ4ed -iPSCs). Extensive differentiation and metabolic assays of control-iPSCs, CQ4-iPSCs and CQ4ed -iPSCs demonstrated a genotype association, reproducing the disease phenotype. The COQ4 mutation in iPSC was associated with CoQ10 deficiency, metabolic dysfunction, and respiration defects. iPSC differentiation into SkM was compromised, and the resulting SkM also displayed respiration defects. Remarkably, iPSC differentiation in dopaminergic or motor neurons was unaffected. This study offers an unprecedented iPSC model recapitulating CoQ10 deficiency-associated functional and metabolic phenotypes caused by COQ4 mutation. Stem Cells 2017;35:1687-1703.
Assuntos
Ataxia/genética , Deficiência Intelectual/genética , Mitocôndrias/genética , Doenças Mitocondriais/genética , Proteínas Mitocondriais/genética , Debilidade Muscular/genética , Rabdomiólise/genética , Ubiquinona/análogos & derivados , Ubiquinona/deficiência , Ataxia/enzimologia , Ataxia/patologia , Sistemas CRISPR-Cas , Diferenciação Celular , Pré-Escolar , Neurônios Dopaminérgicos/citologia , Neurônios Dopaminérgicos/metabolismo , Complexo de Proteínas da Cadeia de Transporte de Elétrons/genética , Complexo de Proteínas da Cadeia de Transporte de Elétrons/metabolismo , Evolução Fatal , Feminino , Fibroblastos/metabolismo , Fibroblastos/patologia , Edição de Genes/métodos , Expressão Gênica , Genes Letais , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Pluripotentes Induzidas/patologia , Deficiência Intelectual/enzimologia , Deficiência Intelectual/patologia , Mitocôndrias/enzimologia , Mitocôndrias/patologia , Doenças Mitocondriais/enzimologia , Doenças Mitocondriais/patologia , Proteínas Mitocondriais/deficiência , Neurônios Motores/citologia , Neurônios Motores/metabolismo , Debilidade Muscular/enzimologia , Debilidade Muscular/patologia , Cultura Primária de Células , Rabdomiólise/enzimologia , Rabdomiólise/patologia , Ubiquinona/genéticaRESUMO
Objective: To study disease severity and response to therapy in a large cohort of patients with anti-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR)-associated myositis. Methods: Muscle strength, creatine kinase levels and treatments were assessed in anti-HMGCR-positive patients at each clinical visit. Univariate and multivariate analyses were used to analyse the influence of clinical characteristics on strength and the change in strength over time. Whole exome sequencing was performed in a subset of patients. Results: . Among 50 patients followed for ⩾2 years, only 22 (44%) reached full strength with immunosuppressive therapy; even among those with full strength, 55% continued to have CK levels in excess of 500 IU/l and only three could be tapered off immunosuppressive therapy. Both univariate and multivariate analysis showed that patients who were older at disease onset were stronger at all time points (P < 0.001) and improved faster (P < 0.008) than younger patients; a history of statin exposure was not independently associated with the improvement rate. Younger patients were more likely to have refractory disease (P = 0.02) than older patients. Among eight refractory patients with DNA available for testing, whole exome sequencing did not reveal pathogenic mutations in known dystrophy genes. The risk of cancer was not increased in anti-HMGCR myositis patients compared with the general population. Conclusions: Anti-HMGCR myositis is usually a chronic disease requiring long-term immunosuppression. Although younger patients had more severe disease and a worse prognosis than older patients, they did not have evidence of a known co-existing muscular dystrophy to explain their persistent, and sometimes progressive, muscle weakness.
Assuntos
Doenças Autoimunes/enzimologia , Hidroximetilglutaril-CoA Redutases/imunologia , Miosite/enzimologia , Adolescente , Adulto , Assistência ao Convalescente , Idade de Início , Idoso , Idoso de 80 Anos ou mais , Autoanticorpos/metabolismo , Doenças Autoimunes/imunologia , Criança , Pré-Escolar , Creatina Quinase/metabolismo , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/efeitos adversos , Imunossupressores/efeitos adversos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Força Muscular/imunologia , Força Muscular/fisiologia , Debilidade Muscular/enzimologia , Debilidade Muscular/imunologia , Músculo Esquelético/enzimologia , Músculo Esquelético/imunologia , Miosite/imunologia , Miosite/terapia , Neoplasias/enzimologia , Neoplasias/imunologia , Prognóstico , Recuperação de Função Fisiológica/imunologia , Recuperação de Função Fisiológica/fisiologia , Estudos Retrospectivos , Fatores de Risco , Adulto JovemRESUMO
OBJECTIVE: To compare the changes in muscle enzyme between children with myocarditis and Duchene/Becker muscular dystrophy (DMD/BMD), and to seek the explanations for variation.â© METHODS: The retrospective analysis for 83 myocarditis children (myocarditis group) and 69 DMD/BMD children (DMD/BMD group), who were collected from Department of Pediatric of Shengjing Hospital affiliated to China Medical University since January 2008 to May 2015, was carried out. At the same time, 24 healthy children from the Department of Pediatric Development served as a control group. The examination indexes included creatine kinase (CK), creatine kinase-isoenzyme MB (CK-MB), creatine kinase isoenzyme MB mass (CK-MB mass), cardiac troponin I (cTnI) and high-sensitive-cTnT (hs-cTnT).â© RESULTS: 1) In the myocarditis group, the CK increased from 100 to 1 000 U/L, reached a peak after 5 days, which lasted for a week and then dropped to the normal; the CK-MB reached a peak after 5 to 7 days and dropped to the normal a month later; the CK-MB mass reached a peak on the first day and dropped to the normal after 3 weeks; the cTn reached to a peak after 5 days and dropped to the normal after about 17 days; hs-cTnT reached to a peak on the first day and dropped to the normal after about 19 days. 2) In the DMD/BMD group, the CK increased significantly and 27 cases had a CK value of more than 10 000 U/L. After the treatment for 1 to 2 weeks, their enzyme rose again after a slight drop. In terms of cTnI, 6 cases showed a moderate increase, 5 of them couldn't drop to the normal level until more than 3 weeks later; the hs-cTnT increased in the 45 cases, which lasted for more than 3 weeks in the 31 cases of them and showed a tendency of persisting increase.â© CONCLUSION: The cTnI and hs-cTnT rise significantly and possess wider observation window than CK and CK-MB mass in myocarditis children, with more sensitive and specific changes. The myocardial damage can occur before myasthenia and keep this trend for a long time in the DMD/BMD children. The trend of cTnI change in myocarditis children is similar to hs-cTnT, while hs-cTnT in DMD/BMD children is more sensitive than cTnI.
Assuntos
Creatina Quinase Forma MB/metabolismo , Creatina Quinase/metabolismo , Distrofia Muscular de Duchenne/enzimologia , Miocardite/enzimologia , Troponina I/metabolismo , Troponina T/metabolismo , Biomarcadores , Criança , China , Creatina Quinase/sangue , Creatina Quinase Forma MB/sangue , Feminino , Humanos , Masculino , Debilidade Muscular/enzimologia , Distrofia Muscular de Duchenne/terapia , Miocardite/terapia , Estudos Retrospectivos , Fatores de Tempo , Troponina I/sangue , Troponina T/sangueRESUMO
In recent years, the analytical determination of coenzyme Q10 (CoQ10) has gained importance in clinical diagnosis and in pharmaceutical quality control. CoQ10 is an important cofactor in the mitochondrial respiratory chain and a potent endogenous antioxidant. CoQ10 deficiency is often associated with numerous diseases and patients with these conditions may benefit from administration of supplements of CoQ10. In this regard, it has been observed that the best benefits are obtained when CoQ10 deficiency is diagnosed and treated early. Therefore, it is of great value to develop analytical methods for the detection and quantification of CoQ10 in this type of disease. The methods above mentioned should be simple enough to be used in routine clinical laboratories as well as in quality control of pharmaceutical formulations containing CoQ10. Here, we discuss the advantages and disadvantages of different methods of CoQ10 analysis.
Assuntos
Ubiquinona/análogos & derivados , Ataxia/diagnóstico , Ataxia/enzimologia , Cromatografia Líquida de Alta Pressão , Eletroforese Capilar , Humanos , Doenças Mitocondriais/diagnóstico , Doenças Mitocondriais/enzimologia , Debilidade Muscular/diagnóstico , Debilidade Muscular/enzimologia , Preparações Farmacêuticas/química , Espectrofotometria , Ubiquinona/análise , Ubiquinona/sangue , Ubiquinona/química , Ubiquinona/deficiência , Ubiquinona/isolamento & purificaçãoRESUMO
Respiratory dysfunction is prevalent in critically ill patients and can lead to adverse clinical outcomes, including respiratory failure and increased mortality. Respiratory muscles, which normally sustain respiration through inspiratory muscle contractions, become weakened during critical illness, and recent studies suggest that respiratory muscle weakness is related to systemic inflammation. Here, we investigate the pathophysiological role of the inflammatory JAK1/3 signaling pathway in diaphragm weakness in two distinct experimental models of critical illness. In the first experiment, mice received subcutaneous injections of PBS or C26 cancer cells and were fed chow formulated with or without the JAK1/3 inhibitor R548 for 26 days. Diaphragm specific force was significantly reduced in tumor-bearing mice receiving standard chow; however, treatment with the JAK1/3 inhibitor completely prevented diaphragm weakness. Diaphragm cross-sectional area was diminished by â¼25% in tumor-bearing mice but was similar to healthy mice in tumor-bearing animals treated with R548. In the second study, mice received sham surgery or coronary artery ligation, leading to myocardial infarction (MI), and were treated with R548 or vehicle 1 h postsurgery, and once daily for 3 days. Diaphragm specific force was comparable between sham surgery/vehicle, sham surgery/R548 and MI/R548 groups, but significantly decreased in the MI/vehicle group. Markers of oxidative damage and activated caspase-3, mechanisms previously identified to reduce muscle contractility, were not elevated in diaphragm extracts. These experiments implicate JAK1/3 signaling in cancer- and MI-mediated diaphragm weakness in mice, and provide a compelling case for further investigation.
Assuntos
Neoplasias do Colo/tratamento farmacológico , Diafragma/efeitos dos fármacos , Janus Quinase 1/antagonistas & inibidores , Janus Quinase 3/antagonistas & inibidores , Força Muscular/efeitos dos fármacos , Debilidade Muscular/prevenção & controle , Infarto do Miocárdio/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Transtornos Respiratórios/prevenção & controle , Animais , Caquexia/enzimologia , Caquexia/etiologia , Caquexia/fisiopatologia , Neoplasias do Colo/complicações , Neoplasias do Colo/enzimologia , Neoplasias do Colo/fisiopatologia , Diafragma/enzimologia , Diafragma/fisiopatologia , Modelos Animais de Doenças , Janus Quinase 1/metabolismo , Janus Quinase 3/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Contração Muscular/efeitos dos fármacos , Debilidade Muscular/enzimologia , Debilidade Muscular/etiologia , Debilidade Muscular/fisiopatologia , Infarto do Miocárdio/complicações , Infarto do Miocárdio/enzimologia , Infarto do Miocárdio/fisiopatologia , Respiração/efeitos dos fármacos , Transtornos Respiratórios/enzimologia , Transtornos Respiratórios/etiologia , Transtornos Respiratórios/fisiopatologia , Transdução de Sinais/efeitos dos fármacosRESUMO
Complex I deficiency causes Leigh syndrome, fatal infant lactic acidosis, and neonatal cardiomyopathy. Mutations in more than 100 nuclear DNA and mitochondrial DNA genes miscode for complex I subunits or assembly factors. ACAD9 is an acyl-CoA dehydrogenase with a novel function in assembly of complex I; biallelic mutations cause progressive encephalomyopathy, recurrent Reye syndrome, and fatal cardiomyopathy. We describe the first autopsy in fatal neonatal lethal lactic acidosis due to mutations in ACAD9 that reduced complex I activity. We identified mitochondrial hyperplasia in cardiac myocytes, diaphragm muscle, and liver and renal tubules in formalin-fixed, paraffin-embedded tissue using immunohistochemistry for mitochondrial antigens. Whole-exome sequencing revealed compound heterozygous variants in the ACAD9 gene: c.187G>T (p.E63*) and c.941T>C (p.L314P). The nonsense mutation causes late infantile lethality; the missense variant is novel. Autopsy-derived fibroblasts had reduced complex I activity (53% of control) with normal activity in complexes II to IV, similar to reported cases of ACAD9 deficiency.
Assuntos
Acidose Láctica/diagnóstico , Acidose/diagnóstico , Acil-CoA Desidrogenase/deficiência , Acil-CoA Desidrogenases/genética , Erros Inatos do Metabolismo dos Aminoácidos/diagnóstico , Cardiomiopatia Hipertrófica/diagnóstico , Códon sem Sentido , Diafragma/patologia , Complexo I de Transporte de Elétrons/deficiência , Túbulos Renais/patologia , Doença de Leigh/diagnóstico , Mitocôndrias Cardíacas/patologia , Mitocôndrias Hepáticas/patologia , Mitocôndrias Musculares/patologia , Doenças Mitocondriais/diagnóstico , Insuficiência de Múltiplos Órgãos/diagnóstico , Debilidade Muscular/diagnóstico , Acidose/enzimologia , Acidose/genética , Acidose/patologia , Acidose Láctica/enzimologia , Acidose Láctica/genética , Acidose Láctica/patologia , Acil-CoA Desidrogenase/genética , Acil-CoA Desidrogenases/deficiência , Erros Inatos do Metabolismo dos Aminoácidos/enzimologia , Erros Inatos do Metabolismo dos Aminoácidos/genética , Erros Inatos do Metabolismo dos Aminoácidos/patologia , Autopsia , Cardiomiopatia Hipertrófica/enzimologia , Cardiomiopatia Hipertrófica/genética , Cardiomiopatia Hipertrófica/patologia , Causas de Morte , Células Cultivadas , Análise Mutacional de DNA , DNA Mitocondrial/genética , Diafragma/enzimologia , Complexo I de Transporte de Elétrons/genética , Evolução Fatal , Fibroblastos/enzimologia , Fibroblastos/patologia , Predisposição Genética para Doença , Humanos , Hiperplasia , Imuno-Histoquímica , Recém-Nascido , Túbulos Renais/enzimologia , Doença de Leigh/enzimologia , Doença de Leigh/genética , Doença de Leigh/patologia , Masculino , Mitocôndrias Cardíacas/enzimologia , Mitocôndrias Hepáticas/enzimologia , Mitocôndrias Musculares/enzimologia , Doenças Mitocondriais/enzimologia , Doenças Mitocondriais/genética , Doenças Mitocondriais/patologia , Insuficiência de Múltiplos Órgãos/enzimologia , Insuficiência de Múltiplos Órgãos/genética , Insuficiência de Múltiplos Órgãos/patologia , Debilidade Muscular/enzimologia , Debilidade Muscular/genética , Debilidade Muscular/patologia , Fenótipo , TransfecçãoRESUMO
Calpain contributes to infection-induced diaphragm dysfunction but the upstream mechanism(s) responsible for calpain activation are poorly understood. It is known, however, that cytokines activate neutral sphingomyelinase (nSMase) and nSMase has downstream effects with the potential to increase calpain activity. We tested the hypothesis that infection-induced skeletal muscle calpain activation is a consequence of nSMase activation. We administered cytomix (20 ng/ml TNF-α, 50 U/ml IL-1ß, 100 U/ml IFN-γ, 10 µg/ml LPS) to C2C12 muscle cells to simulate the effects of infection in vitro and studied mice undergoing cecal ligation puncture (CLP) as an in vivo model of infection. In cell studies, we assessed sphingomyelinase activity, subcellular calcium levels, and calpain activity and determined the effects of inhibiting sphingomyelinase using chemical (GW4869) and genetic (siRNA to nSMase2 and nSMase3) techniques. We assessed diaphragm force and calpain activity and utilized GW4869 to inhibit sphingomyelinase in mice. Cytomix increased cytosolic and mitochondrial calcium levels in C2C12 cells (P < 0.001); addition of GW4869 blocked these increases (P < 0.001). Cytomix also activated calpain, increasing calpain activity (P < 0.02), and the calpain-mediated cleavage of procaspase 12 (P < 0.001). Procaspase 12 cleavage was attenuated by either GW4869 (P < 0.001), BAPTA-AM (P < 0.001), or siRNA to nSMase2 (P < 0.001) but was unaffected by siRNA to nSMase3. GW4869 prevented CLP-induced diaphragm calpain activation and diaphragm weakness in mice. These data suggest that nSMase2 activation is required for the development of infection-induced diaphragm calpain activation and muscle weakness. As a consequence, therapies that inhibit nSMase2 in patients may prevent infection-induced skeletal muscle dysfunction.
Assuntos
Calpaína/metabolismo , Músculo Esquelético/enzimologia , Esfingomielina Fosfodiesterase/fisiologia , Compostos de Anilina/farmacologia , Animais , Compostos de Benzilideno/farmacologia , Linhagem Celular , Diafragma/enzimologia , Diafragma/fisiopatologia , Ativação Enzimática , Lipopolissacarídeos/farmacologia , Camundongos , Força Muscular , Debilidade Muscular/enzimologia , Debilidade Muscular/imunologia , Debilidade Muscular/microbiologia , Proteólise , Sepse/enzimologia , Sepse/fisiopatologiaRESUMO
BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a disease characterized by airflow limitation and inflammation. Meanwhile, COPD also is associated with metabolic disorders, such as skeletal muscle weakness. Strikingly, activation of AMP-activated protein kinase (AMPK) exerts critical roles in energy metabolism. However, it remains unclear whether and how the expression levels of AMPK are affected in the COPD model rats which may lead to the dysfunction of the skeletal muscle in these rats. METHODS: Here we developed a rat model of COPD, and we investigated the morphological changes of peripheral skeletal muscle and measured the levels of tumor necrosis factor -α (TNF-α) and AMPK in skeletal muscle by using approaches that include immunohistochemistry and polymerase chain reaction (PCR). RESULTS: We found that the expression levels of both AMPK mRNA and protein in skeletal muscles were significantly reduced in the COPD model rats, in comparison to those from the control rats, the COPD model rats that received treatments with AICAR and resveratrol, whereas the expression levels of TNF-α were elevated in COPD rats. CONCLUSION: Such findings indicate that AMPK may serve as a target for therapeutic intervention in the treatment of muscle weakness in COPD patients.
Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Debilidade Muscular/enzimologia , Músculo Esquelético/enzimologia , Doença Pulmonar Obstrutiva Crônica/enzimologia , Proteínas Quinases Ativadas por AMP/genética , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/farmacologia , Animais , Anti-Inflamatórios/farmacologia , Modelos Animais de Doenças , Regulação para Baixo , Regulação Enzimológica da Expressão Gênica , Masculino , Debilidade Muscular/tratamento farmacológico , Debilidade Muscular/genética , Debilidade Muscular/imunologia , Debilidade Muscular/patologia , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/imunologia , Músculo Esquelético/patologia , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Doença Pulmonar Obstrutiva Crônica/genética , Doença Pulmonar Obstrutiva Crônica/imunologia , Doença Pulmonar Obstrutiva Crônica/patologia , RNA Mensageiro/metabolismo , Ratos Wistar , Resveratrol , Ribonucleotídeos/farmacologia , Sirtuína 1/metabolismo , Estilbenos/farmacologia , Fatores de Tempo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Human COQ6 encodes a monooxygenase which is responsible for the C5-hydroxylation of the quinone ring of coenzyme Q (CoQ). Mutations in COQ6 cause primary CoQ deficiency, a condition responsive to oral CoQ10 supplementation. Treatment is however still problematic given the poor bioavailability of CoQ10. We employed S. cerevisiae lacking the orthologous gene to characterize the two different human COQ6 isoforms and the mutations found in patients. COQ6 isoform a can partially complement the defective yeast, while isoform b, which lacks part of the FAD-binding domain, is inactive but partially stable, and could have a regulatory/inhibitory function in CoQ10 biosynthesis. Most mutations identified in patients, including the frameshift Q461fs478X mutation, retain residual enzymatic activity, and all patients carry at least one hypomorphic allele, confirming that the complete block of CoQ biosynthesis is lethal. These mutants are also partially stable and allow the assembly of the CoQ biosynthetic complex. In fact treatment with two hydroxylated analogues of 4-hydroxybenzoic acid, namely, vanillic acid or 3-4-hydroxybenzoic acid, restored the respiratory growth of yeast Δcoq6 cells expressing the mutant huCOQ6-isoa proteins. These compounds, and particularly vanillic acid, could therefore represent an interesting therapeutic option for COQ6 patients.
Assuntos
Aminobenzoatos/farmacologia , Hidroxibenzoatos/farmacologia , Mutação , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/efeitos dos fármacos , Ubiquinona/genética , Ácido Vanílico/farmacologia , Sequência de Aminoácidos , Ataxia/tratamento farmacológico , Ataxia/enzimologia , Ataxia/genética , Expressão Gênica , Humanos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/enzimologia , Mitocôndrias/genética , Doenças Mitocondriais/tratamento farmacológico , Doenças Mitocondriais/enzimologia , Doenças Mitocondriais/genética , Modelos Moleculares , Dados de Sequência Molecular , Debilidade Muscular/tratamento farmacológico , Debilidade Muscular/enzimologia , Debilidade Muscular/genética , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Ubiquinona/análogos & derivados , Ubiquinona/química , Ubiquinona/deficiência , Ubiquinona/metabolismoAssuntos
Creatina Quinase/sangue , Força Muscular , Debilidade Muscular/diagnóstico , Distrofia Muscular do Cíngulo dos Membros/diagnóstico , Miosite de Corpos de Inclusão/diagnóstico , Músculo Quadríceps/fisiopatologia , Anoctaminas , Biomarcadores/sangue , Biópsia , Canais de Cloreto/genética , Análise Mutacional de DNA , Diagnóstico Diferencial , Predisposição Genética para Doença , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Debilidade Muscular/sangue , Debilidade Muscular/enzimologia , Debilidade Muscular/genética , Debilidade Muscular/fisiopatologia , Debilidade Muscular/terapia , Distrofia Muscular do Cíngulo dos Membros/sangue , Distrofia Muscular do Cíngulo dos Membros/enzimologia , Distrofia Muscular do Cíngulo dos Membros/genética , Distrofia Muscular do Cíngulo dos Membros/fisiopatologia , Distrofia Muscular do Cíngulo dos Membros/terapia , Mutação , Miosite de Corpos de Inclusão/terapia , Fenótipo , Valor Preditivo dos Testes , Músculo Quadríceps/enzimologia , Procedimentos Desnecessários , Regulação para CimaRESUMO
Glycogen storage diseases are important causes of myopathy and cardiomyopathy. We describe 10 patients from 8 families with childhood or juvenile onset of myopathy, 8 of whom also had rapidly progressive cardiomyopathy, requiring heart transplant in 4. The patients were homozygous or compound heterozygous for missense or truncating mutations in RBCK1, which encodes for a ubiquitin ligase, and had extensive polyglucosan accumulation in skeletal muscle and in the heart in cases of cardiomyopathy. We conclude that RBCK1 deficiency is a frequent cause of polyglucosan storage myopathy associated with progressive muscle weakness and cardiomyopathy.
Assuntos
Doença de Depósito de Glicogênio/enzimologia , Doença de Depósito de Glicogênio/genética , Doenças Musculares/enzimologia , Doenças Musculares/genética , Doenças do Sistema Nervoso/enzimologia , Doenças do Sistema Nervoso/genética , Fatores de Transcrição/deficiência , Ubiquitina/genética , Adolescente , Adulto , Cardiomiopatias/enzimologia , Cardiomiopatias/etiologia , Cardiomiopatias/genética , Feminino , Genoma Humano , Doença de Depósito de Glicogênio/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Debilidade Muscular/enzimologia , Debilidade Muscular/etiologia , Debilidade Muscular/genética , Doenças Musculares/etiologia , Mutação de Sentido Incorreto/genética , Doenças do Sistema Nervoso/complicações , Ubiquitina-Proteína Ligases , Adulto JovemRESUMO
INTRODUCTION: Neurological disorders with low tissue coenzyme Q10 (CoQ10) levels are important to identify, as they may be treatable. METHODS: We evaluated retrospectively clinical, laboratory, and muscle histochemistry and oxidative enzyme characteristics in 49 children with suspected mitochondrial disorders. We compared 18 with CoQ10 deficiency in muscle to 31 with normal CoQ10 values. RESULTS: Muscle from CoQ10-deficient patients averaged 5.5-fold more frequent type 2C muscle fibers than controls (P < 0.0001). A type 2C fiber frequency of ≥ 5% had 89% sensitivity and 84% specificity for CoQ10 deficiency in this cohort. No biopsy showed active myopathy. There were no differences between groups in frequencies of mitochondrial myopathologic, clinical, or laboratory features. Multiple abnormalities in muscle oxidative enzyme activities were more frequent in CoQ10-deficient patients than in controls. CONCLUSIONS: When a childhood mitochondrial disorder is suspected, an increased frequency of type 2C fibers in morphologically normal muscle suggests CoQ10 deficiency.
Assuntos
Doenças Mitocondriais/enzimologia , Fibras Musculares de Contração Rápida/enzimologia , Ubiquinona/análogos & derivados , Anormalidades Múltiplas/diagnóstico , Anormalidades Múltiplas/enzimologia , Anormalidades Múltiplas/patologia , Ataxia/diagnóstico , Ataxia/enzimologia , Ataxia/patologia , Criança , Pré-Escolar , Feminino , Humanos , Incidência , Lactente , Masculino , Doenças Mitocondriais/diagnóstico , Doenças Mitocondriais/patologia , Fibras Musculares de Contração Rápida/citologia , Fibras Musculares de Contração Rápida/patologia , Debilidade Muscular/diagnóstico , Debilidade Muscular/enzimologia , Debilidade Muscular/patologia , Músculo Quadríceps/enzimologia , Músculo Quadríceps/patologia , Estudos Retrospectivos , Sensibilidade e Especificidade , Ubiquinona/biossíntese , Ubiquinona/deficiênciaRESUMO
Taurine (TAU) has a lot of the biological, physiological, and pharmocological functions including anti-inflammatory and anti-oxidative stress. Although previous studies have appreciated the effectiveness of branched-chain amino acids (BCAA) on the delayed-onset muscle soreness (DOMS), consistent finding has not still convinced. The aim of this study was to examine the additional effect of TAU with BCAA on the DOMS and muscle damages after eccentric exercise. Thirty-six untrained male volunteers were equally divided into four groups, and ingested a combination with 2.0 g TAU (or placebo) and 3.2 g BCAA (or placebo), thrice a day, 2 weeks prior to and 4 days after elbow flexion eccentric exercise. Following the period after eccentric exercise, the physiological and blood biochemical markers for DOMS and muscle damage showed improvement in the combination of TAU and BCAA supplementation rather than in the single or placebo supplementations. In conclusion, additional supplement of TAU with BCAA would be a useful way to attenuate DOMS and muscle damages induced by high-intensity exercise.
Assuntos
Aminoácidos de Cadeia Ramificada/uso terapêutico , Exercício Físico , Comportamento Alimentar , Debilidade Muscular/tratamento farmacológico , Músculo Esquelético/patologia , Taurina/uso terapêutico , Aminoácidos de Cadeia Ramificada/administração & dosagem , Aminoácidos de Cadeia Ramificada/farmacologia , Área Sob a Curva , Biomarcadores/sangue , Comportamento Alimentar/efeitos dos fármacos , Humanos , L-Lactato Desidrogenase/sangue , Masculino , Debilidade Muscular/sangue , Debilidade Muscular/enzimologia , Músculo Esquelético/efeitos dos fármacos , Medição da Dor , Taurina/administração & dosagem , Taurina/farmacologia , Adulto JovemRESUMO
Disorders of coenzyme Q(10) (CoQ(10)) biosynthesis represent the most treatable subgroup of mitochondrial diseases. Neurological involvement is frequently observed in CoQ(10) deficiency, typically presenting as cerebellar ataxia and/or seizures. The aetiology of the neurological presentation of CoQ(10) deficiency has yet to be fully elucidated and therefore in order to investigate these phenomena we have established a neuronal cell model of CoQ(10) deficiency by treatment of neuronal SH-SY5Y cell line with para-aminobenzoic acid (PABA). PABA is a competitive inhibitor of the CoQ(10) biosynthetic pathway enzyme, COQ2. PABA treatment (1 mM) resulted in a 54 % decrease (46 % residual CoQ(10)) decrease in neuronal CoQ(10) status (p < 0.01). Reduction of neuronal CoQ(10) status was accompanied by a progressive decrease in mitochondrial respiratory chain enzyme activities, with a 67.5 % decrease in cellular ATP production at 46 % residual CoQ(10). Mitochondrial oxidative stress increased four-fold at 77 % and 46 % residual CoQ(10). A 40 % increase in mitochondrial membrane potential was detected at 46 % residual CoQ(10) with depolarisation following oligomycin treatment suggesting a reversal of complex V activity. This neuronal cell model provides insights into the effects of CoQ(10) deficiency on neuronal mitochondrial function and oxidative stress, and will be an important tool to evaluate candidate therapies for neurological conditions associated with CoQ(10) deficiency.
Assuntos
Ataxia/metabolismo , Mitocôndrias/metabolismo , Doenças Mitocondriais/metabolismo , ATPases Mitocondriais Próton-Translocadoras/metabolismo , Debilidade Muscular/metabolismo , Estresse Oxidativo/fisiologia , Ubiquinona/análogos & derivados , Ácido 4-Aminobenzoico/farmacologia , Trifosfato de Adenosina/metabolismo , Ataxia/enzimologia , Linhagem Celular Tumoral , Ataxia Cerebelar/metabolismo , Ataxia Cerebelar/fisiopatologia , DNA Mitocondrial/genética , Transporte de Elétrons , Metabolismo Energético/efeitos dos fármacos , Metabolismo Energético/fisiologia , Humanos , Potencial da Membrana Mitocondrial/fisiologia , Mitocôndrias/enzimologia , Doenças Mitocondriais/enzimologia , Membranas Mitocondriais/metabolismo , Membranas Mitocondriais/fisiologia , Debilidade Muscular/enzimologia , Ubiquinona/deficiência , Ubiquinona/metabolismoRESUMO
INTRODUCTION: Phosphoglycerate mutase deficiency (PGAM) is a rare metabolic myopathy that results in terminal block in glycogenolysis. Clinically, patients with PGAM deficiency are asymptomatic, except when they engage in brief, strenuous efforts, which may trigger myalgias, cramps, muscle necrosis, and myoglobinuria. An unusual pathologic feature of PGAM deficiency is the association with tubular aggregates. METHODS: We report an African-American patient from Panama with partial deficiency of PGAM who presented with asymptomatic elevation of creatine kinase levels and tubular aggregates on muscle biopsy. RESULTS: Muscle biopsies showed subsarcolemmal and sarcolemmal tubular aggregates in type 2 fibers. Muscle PGAM enzymatic activity was decreased and gene sequencing revealed a heterozygous mutation in codon 78 of exon 1 of the PGAM2 gene, which is located on the short arm of chromosome 7. CONCLUSIONS: PGAM deficiency has been reported in 14 patients, 9 of whom were of African-American ethnicity, and in 5 (36%) tubular aggregates were seen on muscle biopsy. Contrary to previously reported cases, our patient was initially asymptomatic. This further expands the PGAM deficiency phenotype.
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Cãibra Muscular/patologia , Debilidade Muscular/patologia , Músculo Esquelético/patologia , Fosfoglicerato Mutase/deficiência , Adulto , Humanos , Masculino , Cãibra Muscular/enzimologia , Cãibra Muscular/genética , Debilidade Muscular/enzimologia , Debilidade Muscular/genética , Músculo Esquelético/enzimologia , Fosfoglicerato Mutase/genética , Fosfoglicerato Mutase/metabolismoRESUMO
Despite advanced diagnostic procedures in muscle disorders, creatine kinase (CK) activity is still one of the parameters most often investigated in serum. It is used mainly in neuromyology, and helps to differentiate between myogenic and neurogenic processes. Furthermore, it is applied to monitor the course of the disease and treatment results. Occasionally, marked elevated CK activity requires detailed diagnostic work-up, including electrophysiological, histopathological and genetic studies. In some cases, it enables the final diagnosis to be established. However, there is still a group of patients with so-called idiopathic hyper-CKemia and with no evidence of neuromuscular disorder. As little is known about potentially asymptomatic hyper-CK-emia, these patients should be carefully monitored.
Assuntos
Creatina Quinase/sangue , Músculo Esquelético/enzimologia , Doenças Neuromusculares/diagnóstico , Doenças Neuromusculares/enzimologia , Diagnóstico Diferencial , Humanos , Anamnese , Debilidade Muscular/diagnóstico , Debilidade Muscular/enzimologia , Dor/diagnóstico , Dor/enzimologiaRESUMO
Diabetic neuropathy is associated with functional and morphological changes of the neuromuscular junction (NMJ) associated with muscle weakness. This study examines the effect of type 1 diabetes on NMJ function. Swiss Webster mice were made diabetic with three interdaily ip injections of streptozotocin (STZ). Mice were severely hyperglycemic within 7 days after the STZ treatment began. Whereas performance of mice on a rotating rod remained normal, the twitch tension response of the isolated extensor digitorum longus to nerve stimulation was reduced significantly at 4 wk after the onset of STZ-induced hyperglycemia. This mechanical alteration was associated with increased amplitude and prolonged duration of miniature end-plate currents (mEPCs). Prolongation of mEPCs was not due to expression of the embryonic acetylcholine receptor but to reduced muscle expression of acetylcholine esterase (AChE). Greater sensitivity of mEPC decay time to the selective butyrylcholinesterase (BChE) inhibitor PEC suggests that muscle attempts to compensate for reduced AChE levels by increasing expression of BChE. These alterations of AChE are attributed to STZ-induced hyperglycemia since similar mEPC prolongation and reduced AChE expression were found for db/db mice. The reduction of muscle end-plate AChE activity early during the onset of STZ-induced hyperglycemia may contribute to endplate pathology and subsequent muscle weakness during diabetes.
Assuntos
Acetilcolinesterase/deficiência , Diabetes Mellitus Experimental/enzimologia , Diabetes Mellitus Tipo 1/enzimologia , Neuropatias Diabéticas/enzimologia , Doenças da Junção Neuromuscular/enzimologia , Acetilcolinesterase/biossíntese , Animais , Butirilcolinesterase/biossíntese , Inibidores da Colinesterase/farmacologia , Neuropatias Diabéticas/fisiopatologia , Proteínas Ligadas por GPI/biossíntese , Proteínas Ligadas por GPI/deficiência , Hiperglicemia/enzimologia , Hiperglicemia/fisiopatologia , Masculino , Camundongos , Placa Motora/enzimologia , Placa Motora/fisiopatologia , Debilidade Muscular/enzimologia , Debilidade Muscular/fisiopatologia , Doenças da Junção Neuromuscular/fisiopatologia , Fisostigmina/análogos & derivados , Fisostigmina/farmacologiaRESUMO
Pyruvate dehydrogenase kinase 4 (PDK4) mRNA has been reported as an up-regulated gene in the heart and skeletal muscle of carnitine-deficient juvenile visceral steatosis (JVS) mice under fed conditions. PDK4 plays an important role in the inhibition of glucose oxidation via the phosphorylation of pyruvate dehydrogenase complex (PDC). This study evaluated the meaning of increased PDK4 mRNA in glucose metabolism by investigating PDK4 protein levels, PDC activity and glucose uptake by the heart and skeletal muscle of JVS mice. PDK4 protein levels in the heart and skeletal muscle of fed JVS mice were increased in accordance with mRNA levels, and protein was enriched in the mitochondria. PDK4 protein was co-fractionated with PDC in sucrose density gradient centrifugation, like PDK2 protein; however, the activities of the pyruvate dehydrogenase complex (PDC) active form in the heart and skeletal muscle of fed JVS mice were similar to those in fed control mice. Fed JVS mice showed significantly higher glucose uptake in the heart and similar uptake in the skeletal muscle compared with fed control mice. Thus, in carnitine deficiency under fed conditions, glucose was preferentially utilized in the heart as an energy source despite increased PDK4 protein levels in the mitochondria. The preferred glucose utilization may be involved in developing cardiac hypertrophy from carnitine deficiency in fatty acid oxidation abnormality.