Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.506
Filtrar
1.
Int J Mol Sci ; 22(4)2021 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-33670490

RESUMO

The mitochondrial respiratory chain is the main site of reactive oxygen species (ROS) production in the cell. Although mitochondria possess a powerful antioxidant system, an excess of ROS cannot be completely neutralized and cumulative oxidative damage may lead to decreasing mitochondrial efficiency in energy production, as well as an increasing ROS excess, which is known to cause a critical imbalance in antioxidant/oxidant mechanisms and a "vicious circle" in mitochondrial injury. Due to insufficient energy production, chronic exposure to ROS overproduction consequently leads to the oxidative damage of life-important biomolecules, including nucleic acids, proteins, lipids, and amino acids, among others. Different forms of mitochondrial dysfunction (mitochondriopathies) may affect the brain, heart, peripheral nervous and endocrine systems, eyes, ears, gut, and kidney, among other organs. Consequently, mitochondriopathies have been proposed as an attractive diagnostic target to be investigated in any patient with unexplained progressive multisystem disorder. This review article highlights the pathomechanisms of mitochondriopathies, details advanced analytical tools, and suggests predictive approaches, targeted prevention and personalization of medical services as instrumental for the overall management of mitochondriopathy-related cascading pathologies.


Assuntos
Metabolismo Energético , Mitocôndrias/patologia , Doenças Mitocondriais/patologia , Estresse Oxidativo , Animais , Carcinogênese/patologia , Humanos , Mitocôndrias/metabolismo , Doenças Mitocondriais/diagnóstico , Doenças Mitocondriais/metabolismo , Doenças Neurodegenerativas/diagnóstico , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Medicina de Precisão , Espécies Reativas de Oxigênio/metabolismo
2.
Metabolism ; 117: 154723, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33549579

RESUMO

BACKGROUND: Obesity, characterized by excessive expansion of white adipose tissue (WAT), is associated with numerous metabolic complications. Conversely, brown adipose tissue (BAT) and beige fat are thermogenic tissues that protect mice against obesity and related metabolic disorders. We recently reported that deletion of miR-22 enhances energy expenditure and attenuates WAT expansion in response to a high-fat diet (HFD). However, the molecular mechanisms involved in these effects mediated by miR-22 loss are unclear. METHODS AND RESULTS: Here, we show that miR-22 expression is induced during white, beige, and brown adipocyte differentiation in vitro. Deletion of miR-22 reduced white adipocyte differentiation in vitro. Loss of miR-22 prevented HFD-induced expression of adipogenic/lipogenic markers and adipocyte hypertrophy in murine WAT. In addition, deletion of miR-22 protected mice against HFD-induced mitochondrial dysfunction in WAT and BAT. Loss of miR-22 induced WAT browning. Gain- and loss-of-function studies revealed that miR-22 did not affect brown adipogenesis in vitro. Interestingly, miR-22 KO mice fed a HFD displayed increased expression of genes involved in thermogenesis and adrenergic signaling in BAT when compared to WT mice fed the same diet. CONCLUSIONS: Collectively, our findings suggest that loss of miR-22 attenuates fat accumulation in response to a HFD by reducing white adipocyte differentiation and increasing BAT activity, reinforcing miR-22 as a potential therapeutic target for obesity-related disorders.


Assuntos
Tecido Adiposo Bege/metabolismo , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/metabolismo , Dieta Hiperlipídica/efeitos adversos , MicroRNAs/genética , Adipogenia/genética , Animais , Diferenciação Celular/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitocôndrias/metabolismo , Doenças Mitocondriais/genética , Doenças Mitocondriais/metabolismo , Obesidade/genética , Obesidade/metabolismo
3.
Int J Mol Sci ; 22(3)2021 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-33540894

RESUMO

Heart failure remains the most common cause of death in the industrialized world. In spite of new therapeutic interventions that are constantly being developed, it is still not possible to completely protect against heart failure development and progression. This shows how much more research is necessary to understand the underlying mechanisms of this process. In this review, we give a detailed overview of the contribution of impaired mitochondrial dynamics and energy homeostasis during heart failure progression. In particular, we focus on the regulation of fatty acid metabolism and the effects of fatty acid accumulation on mitochondrial structural and functional homeostasis.


Assuntos
Ácidos Graxos/metabolismo , Insuficiência Cardíaca/metabolismo , Mitocôndrias Cardíacas/metabolismo , Dinâmica Mitocondrial , Tecido Adiposo/metabolismo , Sinalização do Cálcio , Cardiomiopatias/metabolismo , Ceramidas/biossíntese , Ciclo do Ácido Cítrico , Progressão da Doença , Ácidos Graxos/efeitos adversos , Homeostase , Humanos , Corpos Cetônicos/metabolismo , Doenças Mitocondriais/metabolismo , Mitofagia , NAD/metabolismo , Pericárdio/metabolismo , Receptores Ativados por Proliferador de Peroxissomo/fisiologia , Proteínas Proto-Oncogênicas c-bcl-2/fisiologia , Espécies Reativas de Oxigênio/metabolismo
4.
Int J Mol Sci ; 22(2)2021 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-33435522

RESUMO

Mitochondria are ubiquitous intracellular organelles found in almost all eukaryotes and involved in various aspects of cellular life, with a primary role in energy production. The interest in this organelle has grown stronger with the discovery of their link to various pathologies, including cancer, aging and neurodegenerative diseases. Indeed, dysfunctional mitochondria cannot provide the required energy to tissues with a high-energy demand, such as heart, brain and muscles, leading to a large spectrum of clinical phenotypes. Mitochondrial defects are at the origin of a group of clinically heterogeneous pathologies, called mitochondrial diseases, with an incidence of 1 in 5000 live births. Primary mitochondrial diseases are associated with genetic mutations both in nuclear and mitochondrial DNA (mtDNA), affecting genes involved in every aspect of the organelle function. As a consequence, it is difficult to find a common cause for mitochondrial diseases and, subsequently, to offer a precise clinical definition of the pathology. Moreover, the complexity of this condition makes it challenging to identify possible therapies or drug targets.


Assuntos
DNA Mitocondrial/genética , Metabolismo Energético/genética , Mitocôndrias/genética , Doenças Mitocondriais/genética , Mutação , Animais , Humanos , Mitocôndrias/metabolismo , Doenças Mitocondriais/metabolismo , Proteínas Mitocondriais/química , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Modelos Moleculares , Conformação Proteica
5.
Int J Mol Sci ; 21(24)2020 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-33352696

RESUMO

COASY protein-associated neurodegeneration (CoPAN) is a rare but devastating genetic autosomal recessive disorder of inborn error of CoA metabolism, which shares with pantothenate kinase-associated neurodegeneration (PKAN) similar features, such as dystonia, parkinsonian traits, cognitive impairment, axonal neuropathy, and brain iron accumulation. These two disorders are part of the big group of neurodegenerations with brain iron accumulation (NBIA) for which no effective treatment is available at the moment. To date, the lack of a mammalian model, fully recapitulating the human disorder, has prevented the elucidation of pathogenesis and the development of therapeutic approaches. To gain new insights into the mechanisms linking CoA metabolism, iron dyshomeostasis, and neurodegeneration, we generated and characterized the first CoPAN disease mammalian model. Since CoA is a crucial metabolite, constitutive ablation of the Coasy gene is incompatible with life. On the contrary, a conditional neuronal-specific Coasy knock-out mouse model consistently developed a severe early onset neurological phenotype characterized by sensorimotor defects and dystonia-like movements, leading to premature death. For the first time, we highlighted defective brain iron homeostasis, elevation of iron, calcium, and magnesium, together with mitochondrial dysfunction. Surprisingly, total brain CoA levels were unchanged, and no signs of neurodegeneration were present.


Assuntos
Coenzima A Ligases/fisiologia , Hemocromatose/patologia , Ferro/metabolismo , Doenças Mitocondriais/patologia , Transtornos Motores/patologia , Neurodegeneração Associada a Pantotenato-Quinase/complicações , Sinapsinas/fisiologia , Animais , Coenzima A/metabolismo , Feminino , Hemocromatose/etiologia , Homeostase , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitocôndrias/genética , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Doenças Mitocondriais/etiologia , Doenças Mitocondriais/metabolismo , Transtornos Motores/etiologia , Transtornos Motores/metabolismo
7.
J Steroid Biochem Mol Biol ; 202: 105730, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32682944

RESUMO

Deficiency in Sphingosine-1-phosphate lyase (S1P lyase) is associated with a multi-systemic disorder incorporating primary adrenal insufficiency (PAI), steroid resistant nephrotic syndrome and neurological dysfunction. Accumulation of sphingolipid intermediates, as seen with loss of function mutations in SGPL1, has been implicated in mitochondrial dysregulation, including alterations in mitochondrial membrane potentials and initiation of mitochondrial apoptosis. For the first time, we investigate the impact of S1P lyase deficiency on mitochondrial morphology and function using patient-derived human dermal fibroblasts and CRISPR engineered SGPL1-knockout HeLa cells. Reduced cortisol output in response to progesterone stimulation was observed in two patient dermal fibroblast cell lines. Mass spectrometric analysis of patient dermal fibroblasts revealed significantly elevated levels of sphingosine-1-phosphate, sphingosine, ceramide species and sphingomyelin when compared to control. Total mitochondrial volume was reduced in both S1P lyase deficient patient and HeLa cell lines. Mitochondrial dynamics and parameters of oxidative phosphorylation were altered when compared to matched controls, though differentially across the cell lines. Mitochondrial dysfunction may represent a major event in the pathogenesis of this disease, associated with severity of phenotype.


Assuntos
Insuficiência Adrenal/metabolismo , Aldeído Liases/deficiência , Mitocôndrias/metabolismo , Doenças Mitocondriais/metabolismo , Insuficiência Adrenal/genética , Aldeído Liases/genética , Respiração Celular , Células Cultivadas , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Humanos , Hidrocortisona/metabolismo , Doenças Mitocondriais/genética , Fosfoproteínas/genética , Progesterona/farmacologia , Pele/citologia
8.
Nat Commun ; 11(1): 2714, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32483148

RESUMO

Electron transport chain (ETC) defects occurring from mitochondrial disease mutations compromise ATP synthesis and render cells vulnerable to nutrient and oxidative stress conditions. This bioenergetic failure is thought to underlie pathologies associated with mitochondrial diseases. However, the precise metabolic processes resulting from a defective mitochondrial ETC that compromise cell viability under stress conditions are not entirely understood. We design a whole genome gain-of-function CRISPR activation screen using human mitochondrial disease complex I (CI) mutant cells to identify genes whose increased function rescue glucose restriction-induced cell death. The top hit of the screen is the cytosolic Malic Enzyme (ME1), that is sufficient to enable survival and proliferation of CI mutant cells under nutrient stress conditions. Unexpectedly, this metabolic rescue is independent of increased ATP synthesis through glycolysis or oxidative phosphorylation, but dependent on ME1-produced NADPH and glutathione (GSH). Survival upon nutrient stress or pentose phosphate pathway (PPP) inhibition depends on compensatory NADPH production through the mitochondrial one-carbon metabolism that is severely compromised in CI mutant cells. Importantly, this defective CI-dependent decrease in mitochondrial NADPH production pathway or genetic ablation of SHMT2 causes strong increases in inflammatory cytokine signatures associated with redox dependent induction of ASK1 and activation of stress kinases p38 and JNK. These studies find that a major defect of CI deficiencies is decreased mitochondrial one-carbon NADPH production that is associated with increased inflammation and cell death.


Assuntos
Complexo I de Transporte de Elétrons/metabolismo , Inflamação/metabolismo , Doenças Mitocondriais/metabolismo , Mutação , NADP/metabolismo , Animais , Morte Celular/genética , Linhagem Celular , Sobrevivência Celular/genética , Complexo I de Transporte de Elétrons/genética , Metabolismo Energético/genética , Glicólise/genética , Humanos , Inflamação/genética , Malato Desidrogenase/genética , Malato Desidrogenase/metabolismo , Camundongos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Doenças Mitocondriais/genética , Fosforilação Oxidativa , Via de Pentose Fosfato/genética
9.
Curr Diab Rep ; 20(6): 20, 2020 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-32306181

RESUMO

PURPOSE OF REVIEW: Impairments in mitochondrial function in patients with insulin resistance and type 2 diabetes have been disputed for decades. This review aims to briefly summarize the current knowledge on mitochondrial dysfunction in metabolic tissues and to particularly focus on addressing a new perspective of mitochondrial dysfunction, the altered capacity of mitochondria to communicate with other organelles within insulin-resistant tissues. RECENT FINDINGS: Organelle interactions are temporally and spatially formed connections essential for normal cell function. Recent studies have shown that mitochondria interact with various cellular organelles, such as the endoplasmic reticulum, lysosomes and lipid droplets, forming inter-organelle junctions. We will discuss the current knowledge on alterations in these mitochondria-organelle interactions in insulin resistance and diabetes, with a focus on changes in mitochondria-lipid droplet communication as a major player in ectopic lipid accumulation, lipotoxicity and insulin resistance.


Assuntos
Comunicação Celular/fisiologia , Diabetes Mellitus Tipo 2/fisiopatologia , Resistência à Insulina/fisiologia , Mitocôndrias/fisiologia , Doenças Mitocondriais/fisiopatologia , Organelas/fisiologia , Membrana Celular/metabolismo , Membrana Celular/fisiologia , Diabetes Mellitus Tipo 2/metabolismo , Retículo Endoplasmático/metabolismo , Retículo Endoplasmático/fisiologia , Complexo de Golgi/metabolismo , Complexo de Golgi/fisiologia , Humanos , Gotículas Lipídicas/metabolismo , Gotículas Lipídicas/fisiologia , Lisossomos/metabolismo , Lisossomos/fisiologia , Mitocôndrias/metabolismo , Doenças Mitocondriais/metabolismo , Organelas/metabolismo , Sobrepeso/metabolismo , Sobrepeso/fisiopatologia , Peroxissomos/metabolismo , Peroxissomos/fisiologia
10.
Metabolism ; 107: 154227, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32275974

RESUMO

OBJECTIVE: L5, a highly electronegative subtype of low-density lipoprotein (LDL), is likely associated with the development of atherosclerosis and cardiovascular diseases. Normal LDL is composed mainly of apolipoprotein (Apo) B, but L5 has additional proteins such as ApoE. We previously demonstrated that L5 induces endothelial cell senescence by increasing mitochondrial reactive oxygen species. In the present study, we examined the effect of L5 on mitochondrial function in cardiomyocytes. METHODS: We used the Seahorse XF24 extracellular flux analyzer to examine the effect of L5 and its components on mitochondrial energy production. The effects of L5 on mitochondrial morphology were examined by immunofluorescence using MitoTracker Green FM and the corresponding probes in H9c2 cardiomyoblasts. Mitochondrial permeability was assessed by using a calcium-induced swelling assay with a voltage-dependent anion-selective channel (VDAC) inhibitor to determine VDAC-dependence both in vitro and in vivo. L5 without ApoE, referred to as △L5, was used to clarify the role of ApoE in L5-induced mitochondrial dysfunction. RESULTS: L5 not only significantly decreased basal (P < 0.05) and maximal respiration (P < 0.01) but also reduced spare respiratory capacity (P < 0.01) in H9c2 cells. Additionally, L5 caused phosphorylation of Drp1 and mitochondrial fission. Recombinant ApoE mimicked the mitochondrial effects of L5, but △L5 did not cause similar effects. After entering cells, ApoE on L5 colocalized with mitochondrial VDAC and caused mitochondria swelling both in vitro and in vivo. This effect was also seen with recombinant ApoE but not △L5. CONCLUSIONS: ApoE may play an important role in electronegative LDL-induced mitochondrial dysfunction through the opening of the mitochondrial permeability transition pore via the interaction of ApoE and VDAC.


Assuntos
Apolipoproteínas E/metabolismo , Lipoproteínas LDL/farmacologia , Doenças Mitocondriais/induzido quimicamente , Doenças Mitocondriais/metabolismo , Miócitos Cardíacos/metabolismo , Animais , Linhagem Celular , Metabolismo Energético/efeitos dos fármacos , Humanos , Técnicas In Vitro , Lipoproteínas LDL/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Membranas Mitocondriais/metabolismo , Dilatação Mitocondrial/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Consumo de Oxigênio/efeitos dos fármacos , Espécies Reativas de Oxigênio
11.
Biomed Res Int ; 2020: 1568209, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32083123

RESUMO

Enhancement of mitochondrial physiological function prevents sepsis-induced dysfunction. The present study aimed to elucidate the mechanism by which hydrogen (H2) affects mitochondrial function in a wild-type (WT) and homozygous nuclear factor erythroid 2-related factor 2 (Nrf2) knockout (KO, Nrf2-/-) murine model of sepsis. In myocardial tissues with severe sepsis, H2 gas treatment reduced mitochondrial dysfunction, whereas zinc protoporphyrin (ZnPPIX) negated these beneficial effects. H2 treatment upregulated the protein expression of mitofusin-2 (Mfn2), peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α), and protein heme oxygenase-1 (HO-1) in WT mice with severe sepsis but not in their Nrf2-/- counterparts, and this upregulation was inhibited in the presence of ZnPPIX. In conclusion, the mechanism by which H2 limits organ damage in mice with severe sepsis involves HO-1, whereas the mechanism that limits severe sepsis-related mitochondrial dysfunction involves both HO-1 and Nrf2.


Assuntos
Hidrogênio/farmacologia , Mitocôndrias Cardíacas/efeitos dos fármacos , Substâncias Protetoras/farmacologia , Sepse/tratamento farmacológico , Animais , Modelos Animais de Doenças , Heme Oxigenase-1/metabolismo , Masculino , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Knockout , Mitocôndrias Cardíacas/metabolismo , Doenças Mitocondriais/tratamento farmacológico , Doenças Mitocondriais/metabolismo , Miocárdio/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Protoporfirinas/farmacologia , Sepse/metabolismo , Regulação para Cima/efeitos dos fármacos
12.
Int J Mol Sci ; 21(3)2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-32033205

RESUMO

Triple negative breast cancer (TNBC) is the most aggressive cancer in women, and despite improved treatments, it remains a major cause of morbidity and mortality. We and others have demonstrated that different hybrid compounds targeting PARP/MAPK or other pathways to inhibit cancer progression may lead to promising therapeutic results. We introduced fluorine to alter the physical properties of the compounds. TSC-3C was one of the generated compounds. Upon treatment with TSC-3C, MDA-MB-231 cell proliferation, invasion, and migration were inhibited. TSC-3C induced MDA-MB-231 cell mitochondrial dysfunction and apoptosis, which may be caused by reducing the level of phosphorylated p44/42 MAPK (ERK1/2) and increasing the level of p-JNK. The present study may help to elucidate the role of the MAPK pathway in the development of breast cancer and may promote further research on halogenated heterocyclic compounds for the treatment of breast cancer.


Assuntos
Apoptose/efeitos dos fármacos , Flúor/farmacologia , Hidrazonas/farmacologia , Doenças Mitocondriais/induzido quimicamente , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Transdução de Sinais/efeitos dos fármacos , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Feminino , Compostos Heterocíclicos/farmacologia , Humanos , Doenças Mitocondriais/metabolismo , Fosforilação/efeitos dos fármacos , Neoplasias de Mama Triplo Negativas/metabolismo
13.
J Neurosci ; 40(9): 1975-1986, 2020 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-32005765

RESUMO

Mitochondrial dysfunction is critically involved in Parkinson's disease, characterized by loss of dopaminergic neurons (DaNs) in the substantia nigra (SNc), whereas DaNs in the neighboring ventral tegmental area (VTA) are much less affected. In contrast to VTA, SNc DaNs engage calcium channels to generate action potentials, which lead to oxidant stress by yet unknown pathways. To determine the molecular mechanisms linking calcium load with selective cell death in the presence of mitochondrial deficiency, we analyzed the mitochondrial redox state and the mitochondrial membrane potential in mice of both sexes with genetically induced, severe mitochondrial dysfunction in DaNs (MitoPark mice), at the same time expressing a redox-sensitive GFP targeted to the mitochondrial matrix. Despite mitochondrial insufficiency in all DaNs, exclusively SNc neurons showed an oxidized redox-system, i.e., a low reduced/oxidized glutathione (GSH-GSSG) ratio. This was mimicked by cyanide, but not by rotenone or antimycin A, making the involvement of reactive oxygen species rather unlikely. Surprisingly, a high mitochondrial inner membrane potential was maintained in MitoPark SNc DaNs. Antagonizing calcium influx into the cell and into mitochondria, respectively, rescued the disturbed redox ratio and induced further hyperpolarization of the inner mitochondrial membrane. Our data therefore show that the constant calcium load in SNc DaNs is counterbalanced by a high mitochondrial inner membrane potential, even under conditions of severe mitochondrial dysfunction, but triggers a detrimental imbalance in the mitochondrial redox system, which will lead to neuron death. Our findings thus reveal a new mechanism, redox imbalance, which underlies the differential vulnerability of DaNs to mitochondrial defects.SIGNIFICANCE STATEMENT Parkinson's disease is characterized by the preferential degeneration of dopaminergic neurons (DaNs) of the substantia nigra pars compacta (SNc), resulting in the characteristic hypokinesia in patients. Ubiquitous pathological triggers cannot be responsible for the selective neuron loss. Here we show that mitochondrial impairment together with elevated calcium burden destabilize the mitochondrial antioxidant defense only in SNc DaNs, and thus promote the increased vulnerability of this neuron population.


Assuntos
Antioxidantes/metabolismo , Cálcio/toxicidade , Neurônios Dopaminérgicos/metabolismo , Neurônios Dopaminérgicos/patologia , Doenças Mitocondriais/metabolismo , Doenças Mitocondriais/patologia , Substância Negra/metabolismo , Substância Negra/patologia , Animais , Calbindina 1/metabolismo , Morte Celular , Cianetos/toxicidade , Feminino , Masculino , Potencial da Membrana Mitocondrial , Camundongos , Membranas Mitocondriais/metabolismo , Oxirredução , Estresse Oxidativo , Área Tegmentar Ventral/metabolismo , Área Tegmentar Ventral/patologia
14.
Am J Hum Genet ; 106(2): 272-279, 2020 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-32004445

RESUMO

Recent studies have identified both recessive and dominant forms of mitochondrial disease that result from ATAD3A variants. The recessive form includes subjects with biallelic deletions mediated by non-allelic homologous recombination. We report five unrelated neonates with a lethal metabolic disorder characterized by cardiomyopathy, corneal opacities, encephalopathy, hypotonia, and seizures in whom a monoallelic reciprocal duplication at the ATAD3 locus was identified. Analysis of the breakpoint junction fragment indicated that these 67 kb heterozygous duplications were likely mediated by non-allelic homologous recombination at regions of high sequence identity in ATAD3A exon 11 and ATAD3C exon 7. At the recombinant junction, the duplication allele produces a fusion gene derived from ATAD3A and ATAD3C, the protein product of which lacks key functional residues. Analysis of fibroblasts derived from two affected individuals shows that the fusion gene product is expressed and stable. These cells display perturbed cholesterol and mitochondrial DNA organization similar to that observed for individuals with severe ATAD3A deficiency. We hypothesize that the fusion protein acts through a dominant-negative mechanism to cause this fatal mitochondrial disorder. Our data delineate a molecular diagnosis for this disorder, extend the clinical spectrum associated with structural variation at the ATAD3 locus, and identify a third mutational mechanism for ATAD3 gene cluster variants. These results further affirm structural variant mutagenesis mechanisms in sporadic disease traits, emphasize the importance of copy number analysis in molecular genomic diagnosis, and highlight some of the challenges of detecting and interpreting clinically relevant rare gene rearrangements from next-generation sequencing data.


Assuntos
ATPases Associadas a Diversas Atividades Celulares/genética , Colesterol/metabolismo , Duplicação Gênica , Recombinação Homóloga , Proteínas de Membrana/genética , Mitocôndrias/patologia , Doenças Mitocondriais/patologia , Proteínas Mitocondriais/genética , ATPases Associadas a Diversas Atividades Celulares/química , Sequência de Aminoácidos , Encefalopatias/etiologia , Encefalopatias/metabolismo , Encefalopatias/patologia , Cardiomiopatias/etiologia , Cardiomiopatias/metabolismo , Cardiomiopatias/patologia , Opacidade da Córnea/etiologia , Opacidade da Córnea/metabolismo , Opacidade da Córnea/patologia , Variações do Número de Cópias de DNA , Feminino , Rearranjo Gênico , Humanos , Lactente , Recém-Nascido , Masculino , Proteínas de Membrana/química , Mitocôndrias/genética , Mitocôndrias/metabolismo , Doenças Mitocondriais/genética , Doenças Mitocondriais/metabolismo , Proteínas Mitocondriais/química , Hipotonia Muscular/etiologia , Hipotonia Muscular/metabolismo , Hipotonia Muscular/patologia , Mutação , Conformação Proteica , Convulsões/etiologia , Convulsões/metabolismo , Convulsões/patologia , Homologia de Sequência
15.
Biochim Biophys Acta Mol Basis Dis ; 1866(6): 165727, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32070771

RESUMO

Mitochondrial complex I (CI), the first multiprotein enzyme complex of the OXPHOS system, executes a major role in cellular ATP generation. Consequently, dysfunction of this complex has been linked to inherited metabolic disorders, including Leigh disease (LD), an often fatal disease in early life. Development of clinical effective treatments for LD remains challenging due to the complex pathophysiological nature. Treatment with the peroxisome proliferation-activated receptor (PPAR) agonist bezafibrate improved disease phenotype in several mitochondrial disease mouse models mediated via enhanced mitochondrial biogenesis and fatty acid ß-oxidation. However, the therapeutic potential of this mixed PPAR (α, δ/ß, γ) agonist is severely hampered by hepatotoxicity, which is possibly caused by activation of PPARγ. Here, we aimed to investigate the effects of the PPARα-specific fibrate clofibrate in mitochondrial CI-deficient (Ndufs4-/-) mice. Clofibrate increased lifespan and motor function of Ndufs4-/- mice, while only marginal hepatotoxic effects were observed. Due to the complex clinical and cellular phenotype of CI-deficiency, we also aimed to investigate the therapeutic potential of clofibrate combined with the redox modulator KH176. As described previously, single treatment with KH176 was beneficial, however, combining clofibrate with KH176 did not result in an additive effect on disease phenotype in Ndufs4-/- mice. Overall, both drugs have promising, but independent and nonadditive, properties for the pharmacological treatment of CI-deficiency-related mitochondrial diseases.


Assuntos
Cromanos/farmacologia , Clofibrato/farmacologia , Complexo I de Transporte de Elétrons/deficiência , Longevidade/efeitos dos fármacos , Doenças Mitocondriais/tratamento farmacológico , Trifosfato de Adenosina/metabolismo , Animais , Bezafibrato/farmacologia , Complexo I de Transporte de Elétrons/genética , Complexo I de Transporte de Elétrons/metabolismo , Ácidos Graxos/metabolismo , Humanos , Doença de Leigh/tratamento farmacológico , Doença de Leigh/metabolismo , Doença de Leigh/patologia , Camundongos , Camundongos Knockout , Mitocôndrias/efeitos dos fármacos , Doenças Mitocondriais/metabolismo , Doenças Mitocondriais/patologia , Atividade Motora/efeitos dos fármacos , Oxirredução/efeitos dos fármacos , Receptores Ativados por Proliferador de Peroxissomo/agonistas , Receptores Ativados por Proliferador de Peroxissomo/genética
16.
Nat Commun ; 11(1): 970, 2020 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-32080200

RESUMO

Deregulation of mitochondrial network in terminally differentiated cells contributes to a broad spectrum of disorders. Methylmalonic acidemia (MMA) is one of the most common inherited metabolic disorders, due to deficiency of the mitochondrial methylmalonyl-coenzyme A mutase (MMUT). How MMUT deficiency triggers cell damage remains unknown, preventing the development of disease-modifying therapies. Here we combine genetic and pharmacological approaches to demonstrate that MMUT deficiency induces metabolic and mitochondrial alterations that are exacerbated by anomalies in PINK1/Parkin-mediated mitophagy, causing the accumulation of dysfunctional mitochondria that trigger epithelial stress and ultimately cell damage. Using drug-disease network perturbation modelling, we predict targetable pathways, whose modulation repairs mitochondrial dysfunctions in patient-derived cells and alleviate phenotype changes in mmut-deficient zebrafish. These results suggest a link between primary MMUT deficiency, diseased mitochondria, mitophagy dysfunction and epithelial stress, and provide potential therapeutic perspectives for MMA.


Assuntos
Erros Inatos do Metabolismo dos Aminoácidos/metabolismo , Erros Inatos do Metabolismo dos Aminoácidos/patologia , Erros Inatos do Metabolismo/metabolismo , Erros Inatos do Metabolismo/patologia , Metilmalonil-CoA Mutase/deficiência , Doenças Mitocondriais/metabolismo , Doenças Mitocondriais/patologia , Mitofagia/fisiologia , Alquil e Aril Transferases/deficiência , Alquil e Aril Transferases/genética , Erros Inatos do Metabolismo dos Aminoácidos/genética , Animais , Modelos Animais de Doenças , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Feminino , Técnicas de Inativação de Genes , Humanos , Masculino , Proteínas de Membrana/deficiência , Proteínas de Membrana/genética , Erros Inatos do Metabolismo/genética , Metilmalonil-CoA Mutase/genética , Metilmalonil-CoA Mutase/metabolismo , Camundongos , Camundongos Knockout , Doenças Mitocondriais/genética , Mitofagia/genética , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Estresse Fisiológico , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Peixe-Zebra
17.
FASEB J ; 34(1): 1859-1871, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31914602

RESUMO

The respiratory chain (RC) transports electrons to form a proton motive force that is required for ATP synthesis in the mitochondria. RC disorders cause mitochondrial diseases that have few effective treatments; therefore, novel therapeutic strategies are critically needed. We previously identified Higd1a as a positive regulator of cytochrome c oxidase (CcO) in the RC. Here, we test that Higd1a has a beneficial effect by increasing CcO activity in the models of mitochondrial dysfunction. We first demonstrated the tissue-protective effects of Higd1a via in situ measurement of mitochondrial ATP concentrations ([ATP]mito) in a zebrafish hypoxia model. Heart-specific Higd1a overexpression mitigated the decline in [ATP]mito under hypoxia and preserved cardiac function in zebrafish. Based on the in vivo results, we examined the effects of exogenous HIGD1A on three cellular models of mitochondrial disease; notably, HIGD1A improved respiratory function that was coupled with increased ATP synthesis and demonstrated cellular protection in all three models. Finally, enzyme kinetic analysis revealed that Higd1a significantly increased the maximal velocity of the reaction between CcO and cytochrome c without changing the affinity between them, indicating that Higd1a is a positive modulator of CcO. These results corroborate that Higd1a, or its mimic, provides therapeutic options for the treatment of mitochondrial diseases.


Assuntos
Transporte de Elétrons/fisiologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Mitocôndrias/metabolismo , Doenças Mitocondriais/metabolismo , Proteínas Mitocondriais/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Animais Geneticamente Modificados , Transporte Biológico/fisiologia , Linhagem Celular , Citocromos c/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Células HEK293 , Humanos , Hipóxia/metabolismo , Cinética , Oxirredução , Respiração , Peixe-Zebra/metabolismo
18.
FASEB J ; 34(1): 303-315, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31914648

RESUMO

Mutations in succinate dehydrogenase (SDH) lead to the development of tumors in a restricted subset of cell types, including chromaffin cells and paraganglia. The molecular basis for this specificity is currently unknown. We show that loss of SDH activity in a chromaffin cell model does not perturb complex I function, retaining the ability to oxidize NADH within the electron transport chain. This activity supports continued oxidation of substrates within the tricarboxylic acid (TCA) cycle. However, due to the block in the TCA cycle at SDH, the high glutamine oxidation activity is only maintained through an efflux of succinate. We also show that although the mitochondria of SDH-deficient cells are less active per se, their higher mass per cell results in an overall respiratory rate that is comparable with wild-type cells. Finally, we observed that when their mitochondria are uncoupled, SDH-deficient cells are unable to preserve their viability, suggesting that the mitochondrial metabolic network is unable to compensate when exposed to additional stress. We therefore show that in contrast to models of SDH deficiency based on epithelial cells, a chromaffin cell model retains aspects of metabolic "health," which could form the basis of cell specificity of this rare tumor type.


Assuntos
Células Cromafins/metabolismo , Complexo I de Transporte de Elétrons/metabolismo , Mitocôndrias/metabolismo , Doenças Mitocondriais/metabolismo , Neoplasias/metabolismo , Succinato Desidrogenase/fisiologia , Animais , Células Cromafins/patologia , Humanos , Masculino , Camundongos , Camundongos Knockout , Mitocôndrias/patologia , Doenças Mitocondriais/patologia , Mutação , NAD/metabolismo , Neoplasias/patologia , Succinato Desidrogenase/genética , Succinato Desidrogenase/metabolismo , Transcriptoma
19.
J Glaucoma ; 29(4): 295-303, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31977544

RESUMO

This review focuses on recent progress in understanding the role of mitochondrial markers in the context of mitochondrial dysfunction in glaucoma and discussing new therapeutic approaches to modulate mitochondrial function and potentially lead to improved outcomes in glaucoma.


Assuntos
Envelhecimento/fisiologia , Biomarcadores/metabolismo , Glaucoma de Ângulo Aberto/metabolismo , Doenças Mitocondriais/metabolismo , Doenças Retinianas/metabolismo , Glaucoma de Ângulo Aberto/fisiopatologia , Humanos
20.
Life Sci ; 244: 117322, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31958419

RESUMO

AIMS: Mitochondrial dysfunction is an early prominent feature of Alzheimer's disease (AD). In the present study, we sought to investigate whether defective mitophagy is tightly related to amyloid-ß (Aß)-induced mitochondrial dysfunction. MAIN METHODS: Immunofluorescence, western blot and transmission electron microscopy were used to examine mitophagy. Mitochondrial membrane potential was assessed using the JC-1 dye. Mitochondrial ROS was detected using MitoSOX™ Red staining. KEY FINDINGS: Aß induced mitochondrial dysfunction in HEK293 cells. Moreover, Aß induced an increase in parkin translocation to mitochondria and led to a drastic reduction in cytosolic parkin. Furthermore, Aß-treated cells displayed a microtubule-associated protein 1 light chain 3 (LC3) punctate pattern and elevated mitochondrial LC3-II levels, suggesting the upregulation of mitophagy. Notably, Aß induced the accumulation of mitochondrial p62, which was associated with impaired mitophagy. In addition, Aß-treated cells exhibited fragmented or swollen mitochondria with severely decreased cristae. We then investigated whether overexpression of parkin could protect cells against Aß-induced mitochondrial dysfunction. Interestingly, parkin overexpression inhibited Aß-induced mitochondrial dysfunction. Besides, parkin overexpression increased cytosolic and mitochondrial parkin levels as well as mitochondrial LC3-II levels in Aß-treated cells. Additionally, parkin overexpression reversed the accumulation of p62 in mitochondria, indicating that parkin overexpression restored impaired mitophagy in Aß-treated cells. Importantly, parkin overexpression remarkably reversed Aß-induced mitochondrial fragmentation. SIGNIFICANCE: Our data demonstrate that overexpression of parkin ameliorates impaired mitophagy and promotes the removal of damaged mitochondria in Aß-treated cells, indicating that upregulation of parkin-mediated mitophagy may be a potential strategy for the therapy of AD.


Assuntos
Peptídeos beta-Amiloides/efeitos adversos , Mitocôndrias/metabolismo , Doenças Mitocondriais/prevenção & controle , Mitofagia , Ubiquitina-Proteína Ligases/metabolismo , Células HEK293 , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/patologia , Doenças Mitocondriais/etiologia , Doenças Mitocondriais/metabolismo , Doenças Mitocondriais/patologia , Espécies Reativas de Oxigênio/metabolismo , Ubiquitina-Proteína Ligases/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...