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1.
Nat Commun ; 12(1): 1190, 2021 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-33608520

RESUMO

DddA-derived cytosine base editors (DdCBEs), composed of the split interbacterial toxin DddAtox, transcription activator-like effector (TALE), and uracil glycosylase inhibitor (UGI), enable targeted C-to-T base conversions in mitochondrial DNA (mtDNA). Here, we demonstrate highly efficient mtDNA editing in mouse embryos using custom-designed DdCBEs. We target the mitochondrial gene, MT-ND5 (ND5), which encodes a subunit of NADH dehydrogenase that catalyzes NADH dehydration and electron transfer to ubiquinone, to obtain several mtDNA mutations, including m.G12918A associated with human mitochondrial diseases and m.C12336T that incorporates a premature stop codon, creating mitochondrial disease models in mice and demonstrating a potential for the treatment of mitochondrial disorders.


Assuntos
DNA Mitocondrial/genética , Edição de Genes/métodos , Genes Mitocondriais/genética , Animais , Transporte de Elétrons , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias , Doenças Mitocondriais/genética , Proteínas Mitocondriais/genética , Mutação , NADH Desidrogenase/genética , Células NIH 3T3 , Efetores Semelhantes a Ativadores de Transcrição/genética
2.
Nucleic Acids Res ; 49(5): 2816-2834, 2021 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-33619562

RESUMO

GTPBP3 and MTO1 cooperatively catalyze 5-taurinomethyluridine (τm5U) biosynthesis at the 34th wobble position of mitochondrial tRNAs. Mutations in tRNAs, GTPBP3 or MTO1, causing τm5U hypomodification, lead to various diseases. However, efficient in vitro reconstitution and mechanistic study of τm5U modification have been challenging, in part due to the lack of pure and active enzymes. A previous study reported that purified human GTPBP3 (hGTPBP3) is inactive in GTP hydrolysis. Here, we identified the mature form of hGTPBP3 and showed that hGTPBP3 is an active GTPase in vitro that is critical for tRNA modification in vivo. Unexpectedly, the isolated G domain and a mutant with the N-terminal domain truncated catalyzed GTP hydrolysis to only a limited extent, exhibiting high Km values compared with that of the mature enzyme. We further described several important pathogenic mutations of hGTPBP3, associated with alterations in hGTPBP3 localization, structure and/or function in vitro and in vivo. Moreover, we discovered a novel cytoplasm-localized isoform of hGTPBP3, indicating an unknown potential noncanonical function of hGTPBP3. Together, our findings established, for the first time, the GTP hydrolysis mechanism of hGTPBP3 and laid a solid foundation for clarifying the τm5U modification mechanism and etiology of τm5U deficiency-related diseases.


Assuntos
Proteínas de Ligação ao GTP/química , Proteínas de Ligação ao GTP/metabolismo , Animais , Domínio Catalítico , Citoplasma/enzimologia , Proteínas de Ligação ao GTP/genética , Células HEK293 , Humanos , Isoenzimas/química , Isoenzimas/metabolismo , Mitocôndrias/enzimologia , Doenças Mitocondriais/genética , Modelos Moleculares , Mutação , Transporte Proteico , Proteínas de Ligação a RNA/metabolismo , Células Sf9
3.
BMJ Case Rep ; 14(2)2021 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-33547122

RESUMO

We herein report a woman who was suffering from type 1 diabetes and hearing impairment and whose mother had mitochondrial disease. Abdominal ultrasound identified a hepatic tumour, and a further examination led to the diagnosis of rectal cancer with synchronous multiple liver metastases. A genetic test led to the diagnosis of mitochondrial disease with a mitochondrial gene 3243A>G mutation. After neoadjuvant chemotherapy, we performed hepatectomy and low anterior resection in one stage. Hepatic vascular exclusion was not performed in order to prevent damage to hepatocytes due to liver ischaemia, and Ringer's lactate solution was not used to prevent lactic acidosis. The postoperative course was uneventful. Only one other case involving hepatectomy being performed in a patient with mitochondrial disease has been reported. Considering the extreme rarity of such cases and the importance of perioperative management, we report this case here.


Assuntos
Hepatectomia , Neoplasias Hepáticas/secundário , Neoplasias Hepáticas/cirurgia , Doenças Mitocondriais/complicações , Neoplasias Retais/patologia , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica , Camptotecina/análogos & derivados , Diabetes Mellitus Tipo 2/genética , Feminino , Fluoruracila , Humanos , Leucovorina , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/tratamento farmacológico , Doenças Mitocondriais/genética , Compostos Organoplatínicos , Linhagem , Neoplasias Retais/diagnóstico por imagem , Neoplasias Retais/tratamento farmacológico , Neoplasias Retais/cirurgia
4.
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
5.
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
6.
Int J Mol Sci ; 22(2)2021 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-33430493

RESUMO

Background: Mitochondrial DNA (mtDNA) diseases are a group of maternally inherited genetic disorders caused by a lack of energy production. Currently, mtDNA diseases have a poor prognosis and no known cure. The chance to have unaffected offspring with a genetic link is important for the affected families, and mitochondrial replacement techniques (MRTs) allow them to do so. MRTs consist of transferring the nuclear DNA from an oocyte with pathogenic mtDNA to an enucleated donor oocyte without pathogenic mtDNA. This paper aims to determine the efficacy, associated risks, and main ethical and legal issues related to MRTs. Methods: A bibliographic review was performed on the MEDLINE and Web of Science databases, along with searches for related clinical trials and news. Results: A total of 48 publications were included for review. Five MRT procedures were identified and their efficacy was compared. Three main risks associated with MRTs were discussed, and the ethical views and legal position of MRTs were reviewed. Conclusions: MRTs are an effective approach to minimizing the risk of transmitting mtDNA diseases, but they do not remove it entirely. Global legal regulation of MRTs is required.


Assuntos
DNA Mitocondrial/genética , DNA/genética , Terapia Genética/tendências , Doenças Mitocondriais/genética , DNA/uso terapêutico , DNA Mitocondrial/uso terapêutico , Humanos , Mitocôndrias/genética , Mitocôndrias/patologia , Doenças Mitocondriais/terapia , Oócitos/citologia
10.
Medicine (Baltimore) ; 99(44): e23026, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-33126389

RESUMO

RATIONALE: The ubiquinol-cytochrome c reductase synthesis-like (BCS1L) gene is located on chromosome 2 (2q35) and encodes an ATPase that is associated with various cellular activities and is embedded in the mitochondrial inner membrane; this ATPase is presumed to facilitate the insertion of the Rieske Fe/S protein into precursors of Complex III (CIII) during the assembly of the respiratory chain. We report the first case of a compound heterozygous mutation in the BCS1L gene in China. PATIENT CONCERNS: A 7-month-old girl presented with a 3-month history of psychomotor developmental retardation and a 1-month history of epilepsy combined with parallel psychomotor developmental deterioration. The clinical manifestations in the patient included psychomotor developmental retardation, infantile spasms, pili torti, tubulopathy, hepatic pathologies and lactic acidosis. DIAGNOSIS: Combined with her clinical presentation, the patient was diagnosed with CIII deficiency and Björnstad syndrome caused by a novel mutation in the BCS1L gene after molecular biological examination. Whole exome sequencing revealed a compound heterozygous mutation with a missense mutation (c.548G > A/p. R183H) inherited from her mother and an insertion mutation (c.1061_1062insCTA/p. G354delinsGY) inherited from her father. INTERVENTIONS: Before admission, the patient had received oral topiramate for 1 month. After admission, additional intravenous arginine hydrochloride was administered for five days in the acute metabolic disorder phase, and persistent cocktail therapy was introduced, including coenzyme Q10 (20 mg/d), carnitine (1 g/d) and vitamins (vitamin B1, vitamin B2, vitamin B6, and vitamin C). OUTCOMES: The spasm seizures were decreased by 50% after 2 weeks of treatment. The blood ammonia, myocardial enzyme and urine glucose levels declined to normal levels. At a 1-month follow-up, the patient improved clinically with a decrease in spasm seizures of 75%, stronger sucking and more voluntary activities. However, she still had mild lactic acidosis and mild hepatic damage. LESSONS: We reported the first patient with CIII deficiency and Björnstad syndrome in China and identified 1 novel mutation (C.1061_1062insCTA and P. G354delinsGY) in the BCS1L gene. This finding expands the BCS1L gene mutation profile and will be beneficial for genetic diagnosis.


Assuntos
Complexo III da Cadeia de Transporte de Elétrons/genética , Predisposição Genética para Doença , Doenças do Cabelo/genética , Perda Auditiva Neurossensorial/genética , Doenças Mitocondriais/congênito , Feminino , Humanos , Lactente , Doenças Mitocondriais/genética , Mutação , Linhagem
11.
PLoS One ; 15(9): e0233666, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32970680

RESUMO

Mitochondrial DNA variants associated with diseases are widely studied in contemporary populations, but their prevalence has not yet been investigated in ancient populations. The publicly available AmtDB database contains 1443 ancient mtDNA Eurasian genomes from different periods. The objective of this study was to use this data to establish the presence of pathogenic mtDNA variants putatively associated with mitochondrial diseases in ancient populations. The clinical significance, pathogenicity prediction and contemporary frequency of mtDNA variants were determined using online platforms. The analyzed ancient mtDNAs contain six variants designated as being "confirmed pathogenic" in modern patients. The oldest of these, m.7510T>C in the MT-TS1 gene, was found in a sample from the Neolithic period, dated 5800-5400 BCE. All six have well established clinical association, and their pathogenic effect is corroborated by very low population frequencies in contemporary populations. Analysis of the geographic location of the ancient samples, contemporary epidemiological trends and probable haplogroup association indicate diverse spatiotemporal dynamics of these variants. The dynamics in the prevalence and distribution is conceivably result of de novo mutations or human migrations and subsequent evolutionary processes. In addition, ten variants designated as possibly or likely pathogenic were found, but the clinical effect of these is not yet well established and further research is warranted. All detected mutations putatively associated with mitochondrial disease in ancient mtDNA samples are in tRNA coding genes. Most of these mutations are in a mt-tRNA type (Model 2) that is characterized by loss of D-loop/T-loop interaction. Exposing pathogenic variants in ancient human populations expands our understanding of their origin and prevalence dynamics.


Assuntos
DNA Antigo , DNA Mitocondrial/genética , Genes Mitocondriais , Doenças Mitocondriais/genética , Bases de Dados Genéticas , Feminino , Humanos , Masculino , Mitocôndrias/genética , Mutação , RNA de Transferência/genética
12.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 37(9): 1009-1013, 2020 Sep 10.
Artigo em Chinês | MEDLINE | ID: mdl-32820518

RESUMO

OBJECTIVE: To analyze the clinical and molecular characteristics of a child with very long chain acyl-CoA dehydrogenase deficiency (VLCADD). METHODS: Peripheral blood sample of the patient was collected for the extraction of genomic DNA. Next generation sequencing (NGS) was carried out for the proband. Suspected mutations were validated by Sanger sequencing. RESULTS: The patient, a 12-month-old girl, was admitted for diarrhea, vomiting, fever, poor spirit and decreased blood pressure. During the course of the disease, she also manifested hypertrophic cardiomyopathy, cardiogenic shock, elevated myocardial enzyme kinase, fever and metabolic acidosis, and had died after three days due to ventricular tachycardia and respiratory failure. Genetic testing showed that she has carried heterozygous mutations of of the ACADVL gene, namely c.664G>A (exon 8) and c.1056_1057del (exon 10). Blood screening for metabolic genetic diseases showed increased C12, C14, C16, C18, C14:1, C14:2, C16:1, C4/C3 and C8/C3, accompanied with decreased C0, C0/C16 and C8/C10. VLCADD and secondary carnitine deficiency could not be excluded, which was in keeping with the result of genetic testing. CONCLUSION: The child was diagnosed with VLCADD, which may be attributed to the compound heterozygous c.664G>A and c.1056_1057del variants of the ACADVL gene.


Assuntos
Acil-CoA Desidrogenase de Cadeia Longa/deficiência , Síndrome Congênita de Insuficiência da Medula Óssea/genética , Erros Inatos do Metabolismo Lipídico/genética , Doenças Mitocondriais/genética , Doenças Musculares/genética , Acil-CoA Desidrogenase de Cadeia Longa/genética , Feminino , Testes Genéticos , Humanos , Lactente
13.
Nat Commun ; 11(1): 4269, 2020 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-32859890

RESUMO

Mitochondria generate most cellular energy via oxidative phosphorylation. Twenty-two species of mitochondrial (mt-)tRNAs encoded in mtDNA translate essential subunits of the respiratory chain complexes. mt-tRNAs contain post-transcriptional modifications introduced by nuclear-encoded tRNA-modifying enzymes. They are required for deciphering genetic code accurately, as well as stabilizing tRNA. Loss of tRNA modifications frequently results in severe pathological consequences. Here, we perform a comprehensive analysis of post-transcriptional modifications of all human mt-tRNAs, including 14 previously-uncharacterized species. In total, we find 18 kinds of RNA modifications at 137 positions (8.7% in 1575 nucleobases) in 22 species of human mt-tRNAs. An up-to-date list of 34 genes responsible for mt-tRNA modifications are provided. We identify two genes required for queuosine (Q) formation in mt-tRNAs. Our results provide insight into the molecular mechanisms underlying the decoding system and could help to elucidate the molecular pathogenesis of human mitochondrial diseases caused by aberrant tRNA modifications.


Assuntos
Processamento Pós-Transcricional do RNA , RNA Mitocondrial/química , RNA de Transferência/química , Feminino , Código Genético , Células HEK293 , Células HeLa , Humanos , Espectrometria de Massas , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Doenças Mitocondriais/genética , Doenças Mitocondriais/patologia , Estrutura Molecular , Nucleosídeo Q/biossíntese , Nucleosídeo Q/química , Fosforilação Oxidativa , Placenta , Gravidez , RNA Mitocondrial/isolamento & purificação , RNA Mitocondrial/metabolismo , RNA de Transferência/isolamento & purificação , RNA de Transferência/metabolismo , RNA-Seq
14.
Nature ; 583(7817): 631-637, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32641830

RESUMO

Bacterial toxins represent a vast reservoir of biochemical diversity that can be repurposed for biomedical applications. Such proteins include a group of predicted interbacterial toxins of the deaminase superfamily, members of which have found application in gene-editing techniques1,2. Because previously described cytidine deaminases operate on single-stranded nucleic acids3, their use in base editing requires the unwinding of double-stranded DNA (dsDNA)-for example by a CRISPR-Cas9 system. Base editing within mitochondrial DNA (mtDNA), however, has thus far been hindered by challenges associated with the delivery of guide RNA into the mitochondria4. As a consequence, manipulation of mtDNA to date has been limited to the targeted destruction of the mitochondrial genome by designer nucleases9,10.Here we describe an interbacterial toxin, which we name DddA, that catalyses the deamination of cytidines within dsDNA. We engineered split-DddA halves that are non-toxic and inactive until brought together on target DNA by adjacently bound programmable DNA-binding proteins. Fusions of the split-DddA halves, transcription activator-like effector array proteins, and a uracil glycosylase inhibitor resulted in RNA-free DddA-derived cytosine base editors (DdCBEs) that catalyse C•G-to-T•A conversions in human mtDNA with high target specificity and product purity. We used DdCBEs to model a disease-associated mtDNA mutation in human cells, resulting in changes in respiration rates and oxidative phosphorylation. CRISPR-free DdCBEs enable the precise manipulation of mtDNA, rather than the elimination of mtDNA copies that results from its cleavage by targeted nucleases, with broad implications for the study and potential treatment of mitochondrial disorders.


Assuntos
Toxinas Bacterianas/metabolismo , Citidina Desaminase/metabolismo , DNA Mitocondrial/genética , Edição de Genes/métodos , Genes Mitocondriais/genética , Mitocôndrias/genética , Toxinas Bacterianas/química , Toxinas Bacterianas/genética , Sequência de Bases , Burkholderia cenocepacia/enzimologia , Burkholderia cenocepacia/genética , Respiração Celular/genética , Citidina/metabolismo , Citidina Desaminase/química , Citidina Desaminase/genética , Genoma Mitocondrial/genética , Células HEK293 , Humanos , Doenças Mitocondriais/genética , Doenças Mitocondriais/terapia , Mutação , Fosforilação Oxidativa , Engenharia de Proteínas , RNA Guia/genética , Especificidade por Substrato , Sistemas de Secreção Tipo VI/metabolismo
16.
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
18.
DNA Cell Biol ; 39(8): 1431-1443, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32598172

RESUMO

Mitochondria contain their own genome, mitochondrial DNA (mtDNA), essential to support their fundamental intracellular role in ATP production and other key metabolic and homeostatic pathways. Mitochondria are highly dynamic organelles that communicate with all the other cellular compartments, through sites of high physical proximity. Among all, their crosstalk with the endoplasmic reticulum (ER) appears particularly important as its derangement is tightly implicated with several human disorders. Population-specific mtDNA variants clustered in defining the haplogroups have been shown to exacerbate or mitigate these pathological conditions. The exact mechanisms of the mtDNA background-modifying effect are not completely clear and a possible explanation is the outcome of mitochondrial efficiency on retrograde signaling to the nucleus. However, the possibility that different haplogroups shape the proximity and crosstalk between mitochondria and the ER has never been proposed neither investigated. In this study, we pose and discuss this question and provide preliminary data to answer it. Besides, we also address the possibility that single, disease-causing mtDNA point mutations may act also by reshaping organelle communication. Overall, this perspective review provides a theoretical platform for future studies on the interaction between mtDNA variants and organelle contact sites.


Assuntos
DNA Mitocondrial/genética , Retículo Endoplasmático/genética , Mitocôndrias/genética , Doenças Mitocondriais/genética , Trifosfato de Adenosina/genética , Trifosfato de Adenosina/metabolismo , Genoma Mitocondrial/genética , Humanos , Mitocôndrias/patologia , Doenças Mitocondriais/patologia
19.
Saudi Med J ; 41(6): 590-596, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32518924

RESUMO

OBJECTIVES: To describe the clinical and molecular characteristics of patients with very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency.   Methods: A retrospective observational cross-sectional analysis was conducted on all patients with VLCAD deficiency at  (Genetic/Metabolic Section), Prince Sultan Military Medical City (PSMMC), Riyadh, Saudi Arabia from 2000 to 2019. Demographic, clinical, and laboratory data were abstracted from the electronic hospital records using a case report form. Results: A total of 14 children were analyzed. Six presented with hypoglycemia, 4 with cardiomyopathy, and 10 had rhabdomyolysis. Five patients had early onset severe phenotype, while 9 had mild form. The molecular study revealed homozygous mutations in ACADVL in all 14 patients. Three variants were not reported before. All patients were treated with medium-chain triglyceride and carnitine. Ten patients are alive and have normal development, while 4 died. Conclusion: Most of the patients in this cohort presented in the neonatal period either by newborn screening or clinically with hypoglycemia, cardiomyopathy, and rhabdomyolysis. The new molecular variants detected in this study broaden the genetic spectrum of VLCAD deficiency in Saudi Arabia.


Assuntos
Acil-CoA Desidrogenase de Cadeia Longa/deficiência , Síndrome Congênita de Insuficiência da Medula Óssea , Erros Inatos do Metabolismo Lipídico , Doenças Mitocondriais , Doenças Musculares , Acil-CoA Desidrogenase de Cadeia Longa/genética , Cardiomiopatias/etiologia , Carnitina/uso terapêutico , Estudos de Coortes , Síndrome Congênita de Insuficiência da Medula Óssea/diagnóstico , Síndrome Congênita de Insuficiência da Medula Óssea/tratamento farmacológico , Síndrome Congênita de Insuficiência da Medula Óssea/genética , Estudos Transversais , Homozigoto , Humanos , Hipoglicemia/etiologia , Recém-Nascido , Erros Inatos do Metabolismo Lipídico/diagnóstico , Erros Inatos do Metabolismo Lipídico/tratamento farmacológico , Erros Inatos do Metabolismo Lipídico/genética , Doenças Mitocondriais/diagnóstico , Doenças Mitocondriais/tratamento farmacológico , Doenças Mitocondriais/genética , Doenças Musculares/diagnóstico , Doenças Musculares/tratamento farmacológico , Doenças Musculares/genética , Mutação , Triagem Neonatal , Rabdomiólise/etiologia , Arábia Saudita , Triglicerídeos/uso terapêutico
20.
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
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