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1.
Int J Mol Sci ; 22(3)2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33498463

RESUMO

DNA methylation is an epigenetic change to the genome that impacts gene activities without modification to the DNA sequence. Alteration in the methylation pattern is a naturally occurring event throughout the human life cycle which may result in the development of diseases such as cancer. In this study, we analyzed methylation data from The Cancer Genome Atlas, under the Lower-Grade Glioma (LGG) and Glioblastoma Multiforme (GBM) projects, to identify methylation markers that exhibit unique changes in DNA methylation pattern along with tumor grade progression, to predict patient survival. We found ten glioma grade-associated Cytosine-phosphate-Guanine (CpG) sites that targeted four genes (SMOC1, KCNA4, SLC25A21, and UPP1) and the methylation pattern is strongly associated with glioma specific molecular alterations, primarily isocitrate dehydrogenase (IDH) mutation and chromosome 1p/19q codeletion. The ten CpG sites collectively distinguished a cohort of diffuse glioma patients with remarkably poor survival probability. Our study highlights genes (KCNA4 and SLC25A21) that were not previously associated with gliomas to have contributed to the poorer patient outcome. These CpG sites can aid glioma tumor progression monitoring and serve as prognostic markers to identify patients diagnosed with less aggressive and malignant gliomas that exhibit similar survival probability to GBM patients.


Assuntos
Biomarcadores Tumorais/genética , Neoplasias Encefálicas/genética , Metilação de DNA , Glioma/genética , Neoplasias Encefálicas/patologia , Transportadores de Ácidos Dicarboxílicos/genética , Glioma/patologia , Humanos , Canal de Potássio Kv1.4/genética , Pessoa de Meia-Idade , Proteínas de Transporte da Membrana Mitocondrial/genética , Osteonectina/genética , Prognóstico , Uridina Fosforilase/genética
2.
Nat Commun ; 11(1): 4589, 2020 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-32917887

RESUMO

Mandibuloacral dysplasia syndromes are mainly due to recessive LMNA or ZMPSTE24 mutations, with cardinal nuclear morphological abnormalities and dysfunction. We report five homozygous null mutations in MTX2, encoding Metaxin-2 (MTX2), an outer mitochondrial membrane protein, in patients presenting with a severe laminopathy-like mandibuloacral dysplasia characterized by growth retardation, bone resorption, arterial calcification, renal glomerulosclerosis and severe hypertension. Loss of MTX2 in patients' primary fibroblasts leads to loss of Metaxin-1 (MTX1) and mitochondrial dysfunction, including network fragmentation and oxidative phosphorylation impairment. Furthermore, patients' fibroblasts are resistant to induced apoptosis, leading to increased cell senescence and mitophagy and reduced proliferation. Interestingly, secondary nuclear morphological defects are observed in both MTX2-mutant fibroblasts and mtx-2-depleted C. elegans. We thus report the identification of a severe premature aging syndrome revealing an unsuspected link between mitochondrial composition and function and nuclear morphology, establishing a pathophysiological link with premature aging laminopathies and likely explaining common clinical features.


Assuntos
Acro-Osteólise/metabolismo , Predisposição Genética para Doença/genética , Lipodistrofia/metabolismo , Mandíbula/anormalidades , Proteínas de Membrana/metabolismo , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Acro-Osteólise/diagnóstico por imagem , Acro-Osteólise/genética , Acro-Osteólise/patologia , Senilidade Prematura/genética , Senilidade Prematura/metabolismo , Animais , Apoptose , Caenorhabditis elegans , Proliferação de Células , Criança , Regulação para Baixo , Feminino , Fibroblastos/metabolismo , Fibroblastos/patologia , Regulação da Expressão Gênica , Genótipo , Homozigoto , Humanos , Lipodistrofia/diagnóstico por imagem , Lipodistrofia/genética , Lipodistrofia/patologia , Masculino , Mandíbula/diagnóstico por imagem , Proteínas de Membrana/genética , Metaloendopeptidases , Proteínas de Transporte da Membrana Mitocondrial/genética , Proteínas Mitocondriais/genética , Mutação , Fenótipo , Pele , Sequenciamento Completo do Genoma
3.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 37(8): 828-832, 2020 Aug 10.
Artigo em Chinês | MEDLINE | ID: mdl-32761588

RESUMO

OBJECTIVE: To explore the genetic basis for a child with concomitant spinal muscular atrophy (SMA) and Citrin protein deficiency. METHODS: The child was subjected to whole exome sequencing by using target sequence capture high-throughput sequencing. Candidate variants were verified by Sanger sequencing. The SMN genes of the patient were also analyzed through multiplex ligation-dependent probe amplification (MLPA). RESULTS: The patient was found to carry homozygous deletion of exons 7 and 8 of the SMN1 gene, for which his parents were both carriers. The patient also carried compound heterozygous variants c.1737G>A and IVS16ins3kbof the SLA25A13 gene, in addition with compound heterozygous variants c.948G>A and c.2693T>C of the POLG gene, for which his parents were carriers, too. CONCLUSION: Variants of the SLC25A13 gene probably underlay the deficiency of Citrin protein, which may lead to neonatal intrahepatic cholestasis (NICCD). The patient also had SMA. The compound heterozygous variants c.948G>A and c.2693T>C of the POLG gene are likely to cause mitochondrial DNA deletion syndrome type 4A, though other types of mitochondrial disease cannot be excluded.


Assuntos
Proteínas de Ligação ao Cálcio/genética , Atrofia Muscular Espinal/genética , Transportadores de Ânions Orgânicos/genética , Deficiência de Proteína/genética , Proteínas de Ligação ao Cálcio/deficiência , Criança , Polimerase do DNA Mitocondrial/genética , Homozigoto , Humanos , Proteínas de Transporte da Membrana Mitocondrial/genética , Transportadores de Ânions Orgânicos/deficiência , Deleção de Sequência , Proteína 1 de Sobrevivência do Neurônio Motor/genética
4.
Tumour Biol ; 42(8): 1010428320951057, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32829673

RESUMO

The exchange of metabolites between mitochondria and cytosol occurs through pores formed by voltage-dependent anion channel proteins. Voltage-dependent anion channels appear to be master regulators of mitochondrial bioenergetics and the intracellular flow of energy. Deregulation of voltage-dependent anion channels expression is thought to be related to mitochondrial dysfunction in cancer. The aim of this study was to investigate the mRNA and protein expression levels of VDAC1, VDAC2, and VDAC3 in relation to clinicopathological characteristics of endometrial cancer as well as the prognostic significance of voltage-dependent anion channels expression for overall survival. VDAC1 and VDAC3 expressions were significantly higher in cancer compared to normal tissues. Kaplan-Meier analysis indicated that high expression of all VDAC genes or high VDAC2 protein level predicted poor overall survival. Multivariate analysis identified the VDAC1 and VDAC2 mRNA levels as well as VDAC2 protein level as independent prognostic factors. Our results suggest that increased expression of voltage-dependent anion channels correlates with tumor progression and may serve as a potential prognostic biomarker in endometrial cancer.


Assuntos
Neoplasias do Endométrio/patologia , Mitocôndrias/patologia , Proteínas de Transporte da Membrana Mitocondrial/genética , Canal de Ânion 1 Dependente de Voltagem/genética , Canal de Ânion 2 Dependente de Voltagem/genética , Canais de Ânion Dependentes de Voltagem/genética , Sequência de Aminoácidos , Biomarcadores Tumorais/genética , Citoplasma/metabolismo , Neoplasias do Endométrio/mortalidade , Feminino , Humanos , Pessoa de Meia-Idade , Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/biossíntese , Prognóstico , RNA Mensageiro/genética , Canal de Ânion 1 Dependente de Voltagem/biossíntese , Canal de Ânion 2 Dependente de Voltagem/biossíntese , Canais de Ânion Dependentes de Voltagem/biossíntese
5.
Proc Natl Acad Sci U S A ; 117(36): 22204-22213, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32848060

RESUMO

The peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) is a transcriptional coactivator that controls expression of metabolic/energetic genes, programming cellular responses to nutrient and environmental adaptations such as fasting, cold, or exercise. Unlike other coactivators, PGC-1α contains protein domains involved in RNA regulation such as serine/arginine (SR) and RNA recognition motifs (RRMs). However, the RNA targets of PGC-1α and how they pertain to metabolism are unknown. To address this, we performed enhanced ultraviolet (UV) cross-linking and immunoprecipitation followed by sequencing (eCLIP-seq) in primary hepatocytes induced with glucagon. A large fraction of RNAs bound to PGC-1α were intronic sequences of genes involved in transcriptional, signaling, or metabolic function linked to glucagon and fasting responses, but were not the canonical direct transcriptional PGC-1α targets such as OXPHOS or gluconeogenic genes. Among the top-scoring RNA sequences bound to PGC-1α were Foxo1, Camk1δ, Per1, Klf15, Pln4, Cluh, Trpc5, Gfra1, and Slc25a25 PGC-1α depletion decreased a fraction of these glucagon-induced messenger RNA (mRNA) transcript levels. Importantly, knockdown of several of these genes affected glucagon-dependent glucose production, a PGC-1α-regulated metabolic pathway. These studies show that PGC-1α binds to intronic RNA sequences, some of them controlling transcript levels associated with glucagon action.


Assuntos
Glucagon/metabolismo , Glucagon/farmacologia , Hepatócitos/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Células Cultivadas , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/fisiologia , Gluconeogênese/fisiologia , Glucose/metabolismo , Guanosina Trifosfato/metabolismo , Fígado/metabolismo , Masculino , Metabolômica , Camundongos , Camundongos Endogâmicos C57BL , Proteínas de Transporte da Membrana Mitocondrial/genética , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Ligação Proteica , Transcriptoma
6.
Anim Sci J ; 91(1): e13430, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32677174

RESUMO

Mitochondria are necessary for the transition from oocyte to embryo and for early embryonic development. Mitofusin 1 is the main mediator of mitochondrial fusion and homeostasis. We investigated Mitofusin 1 expression levels in porcine somatic cell nuclear transfer (SCNT) embryos. The rate of blastocyst formation in SCNT embryos was reduced significantly compared with that of parthenogenetic activation embryos. SCNT embryos showed significantly decreased Mitofusin 1 expression and mitochondrial membrane potential, while exhibiting increased reactive oxygen species and apoptosis. Mitochondrial functional changes were observed in the SCNT embryos and may be correlated with low levels of Mitofusin 1 to negatively affect development.


Assuntos
Apoptose/genética , Blastocisto , Embrião de Mamíferos/metabolismo , Desenvolvimento Embrionário/genética , Regulação da Expressão Gênica no Desenvolvimento/genética , Expressão Gênica/genética , Estudos de Associação Genética/veterinária , Potencial da Membrana Mitocondrial/genética , Proteínas de Transporte da Membrana Mitocondrial/genética , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Partenogênese/genética , Suínos/genética , Suínos/fisiologia , Animais , Células Cultivadas , Técnicas de Cultura Embrionária/veterinária , Fertilização In Vitro/veterinária , Técnicas de Transferência Nuclear/veterinária , Espécies Reativas de Oxigênio/metabolismo
8.
Nat Commun ; 11(1): 3290, 2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32620929

RESUMO

In mitochondria, ß-barrel outer membrane proteins mediate protein import, metabolite transport, lipid transport, and biogenesis. The Sorting and Assembly Machinery (SAM) complex consists of three proteins that assemble as a 1:1:1 complex to fold ß-barrel proteins and insert them into the mitochondrial outer membrane. We report cryoEM structures of the SAM complex from Myceliophthora thermophila, which show that Sam50 forms a 16-stranded transmembrane ß-barrel with a single polypeptide-transport-associated (POTRA) domain extending into the intermembrane space. Sam35 and Sam37 are located on the cytosolic side of the outer membrane, with Sam35 capping Sam50, and Sam37 interacting extensively with Sam35. Sam35 and Sam37 each adopt a GST-like fold, with no functional, structural, or sequence similarity to their bacterial counterparts. Structural analysis shows how the Sam50 ß-barrel opens a lateral gate to accommodate its substrates.


Assuntos
Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Membranas Mitocondriais/metabolismo , Biossíntese de Proteínas , Saccharomyces cerevisiae/metabolismo , Sequência de Aminoácidos , Microscopia Crioeletrônica , Detergentes/química , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Mitocôndrias/genética , Mitocôndrias/ultraestrutura , Proteínas de Transporte da Membrana Mitocondrial/química , Proteínas de Transporte da Membrana Mitocondrial/genética , Complexos Multiproteicos/química , Complexos Multiproteicos/metabolismo , Complexos Multiproteicos/ultraestrutura , Conformação Proteica , Dobramento de Proteína , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Homologia de Sequência de Aminoácidos , Sordariales/genética , Sordariales/metabolismo
9.
Gene ; 754: 144854, 2020 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-32525045

RESUMO

Alzheimer's disease (AD) is one of the most common forms of neurodegenerative diseases. Aggregation of Aß42 and hyperphosphorylated tau are two major hallmarks of AD. Whether different forms of tau (soluble or hyperphosphorylated) or Aß are the main culprit in the events observed in AD is still under investigation. Here, we examined the effect of wild-type, prone to hyperphosphorylation and hyperphosphorylated tau, and also Aß42 peptide on the brain antioxidant defense system and two mitochondrial genes, Marf (homologous to human MFN2) and Drp1 involved in mitochondrial dynamics in transgenic Drosophila melanogaster. AD is an age associated disease. Therefore, the activity of antioxidant agents, CAT, SOD, and GSH levels and the mRNA levels of Marf and Drp1 were assessed in different time points of the flies lifespan. Reduction in cognitive function and antioxidant activity was observed in all transgenic flies at any time point. The most and the least effect on the eye phenotype was exerted by hyperphosphorylated tau and Aß42, respectively. In addition, the most remarkable alteration in Marf and Drp1 mRNA levels was observed in transgenic flies expressing hyperphosphorylated tau when pan neuronal expression of transgenes was applied. However, when the disease causing gene expression was confined to the mushroom body, Marf and Drp1 mRNA levels alteration was more prominent in tauWT and tauE14 transgenic flies, respectively. In conclusion, in spite of antioxidant deficiency caused by different types of tau and Aß42, it seems that tau exerts more toxic effect on the eye phenotype and mitochondrial genes regulation (Marf and Drp1). Moreover, different mechanisms seem to be involved in mitochondrial genes dysregulation when Aß or various forms of tau are expressed.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Animais Geneticamente Modificados/metabolismo , Drosophila melanogaster/metabolismo , Dinaminas/metabolismo , GTP Fosfo-Hidrolases/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , RNA Mensageiro/metabolismo , Proteínas tau/metabolismo , Animais , Animais Geneticamente Modificados/genética , Encéfalo/metabolismo , Drosophila melanogaster/genética , Dinaminas/genética , GTP Fosfo-Hidrolases/genética , Regulação da Expressão Gênica , Transtornos da Memória/metabolismo , Transtornos da Memória/patologia , Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/genética , Fosforilação , RNA Mensageiro/genética , Proteínas tau/genética
10.
Science ; 368(6498): 1495-1499, 2020 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-32587022

RESUMO

Although sled dogs are one of the most specialized groups of dogs, their origin and evolution has received much less attention than many other dog groups. We applied a genomic approach to investigate their spatiotemporal emergence by sequencing the genomes of 10 modern Greenland sled dogs, an ~9500-year-old Siberian dog associated with archaeological evidence for sled technology, and an ~33,000-year-old Siberian wolf. We found noteworthy genetic similarity between the ancient dog and modern sled dogs. We detected gene flow from Pleistocene Siberian wolves, but not modern American wolves, to present-day sled dogs. The results indicate that the major ancestry of modern sled dogs traces back to Siberia, where sled dog-specific haplotypes of genes that potentially relate to Arctic adaptation were established by 9500 years ago.


Assuntos
Adaptação Fisiológica/genética , Cães/genética , Animais , Apolipoproteínas/genética , Regiões Árticas , Ácidos Graxos/metabolismo , Genoma , Groenlândia , Haplótipos , Proteínas de Transporte da Membrana Mitocondrial/genética , Seleção Artificial , Análise de Sequência de DNA , Sibéria , Triglicerídeos/metabolismo , Lobos/genética
11.
J Mol Biol ; 432(10): 3326-3337, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32277989

RESUMO

In the intermembrane space (IMS) of mitochondria, the receptor domain of Tim23 has an essential role during translocation of hundreds of different proteins from the cytosol via the TOM and TIM23 complexes in the outer and inner membranes, respectively. This intrinsically disordered domain, which can even extend into the cytosol, was shown, mostly in vitro, to interact with several subunits of the TOM and TIM23 complexes. To obtain molecular understanding of this organizational hub in the IMS, we dissected the IMS domain of Tim23 in vivo. We show that the interaction surface of Tim23 with Tim50 is larger than previously thought and reveal an unexpected interaction of Tim23 with Pam17 in the IMS, impairment of which influences their interaction in the matrix. Furthermore, mutations of two conserved negatively charged residues of Tim23, close to the inner membrane, prevented dimerization of Tim23. The same mutations increased exposure of Tim23 on the mitochondrial surface, whereas dissipation of membrane potential decreased it. Our results reveal an intricate network of Tim23 interactions in the IMS, whose influence is transduced across two mitochondrial membranes, ensuring efficient translocation of proteins into mitochondria.


Assuntos
Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/química , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Mutação , Sítios de Ligação , Proteínas de Transporte da Membrana Mitocondrial/genética , Modelos Moleculares , Ligação Proteica , Domínios Proteicos , Transporte Proteico , Desdobramento de Proteína
12.
Biochem Pharmacol ; 177: 113995, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32339494

RESUMO

Few discoveries have influenced drug discovery programs more than the finding that mitochondrial membranes undergo swings in permeability in response to cellular perturbations. The conductor of these permeability changes is the aptly named mitochondrial permeability transition pore which, although not yet precisely defined, is comprised of several integral proteins that differentially act to regulate the flux of ions, proteins and metabolic byproducts during the course of cellular physiological functions but also pathophysiological insults. Pursuit of the pore's exact identity remains a topic of keen interest, but decades of research have unearthed provocative functions for the integral proteins leading to their evaluation to develop novel therapeutics for a wide range of clinical indications. Chief amongst these targeted, integral proteins have been the Voltage Dependent Anion Channel (VDAC) and the F1FO ATP synthase. Research associated with the roles and ligands of VDAC has been extensive and we will expand upon 3 examples of ligand:VDAC interactions for consideration of drug discovery projects: Tubulin:VDAC1, Hexokinase I/II:VDAC1 and olesoxime:VDAC1. The discoveries that cyclosporine blocks mitochondrial permeability transition via binding to cyclophilin D, and that cyclophilin D is an important component of F1FO ATP synthase, has heightened interest in the F1FO ATP synthase as a focal point for drug discovery, and we will discuss 2 plausible campaigns associated with disease indications. To date no drug has emerged from prospective targeting these integral proteins; however, continued exploration such as the approaches suggested in this Commentary will increase the likelihood of providing important therapeutics for severely unmet medical needs.


Assuntos
Esclerose Amiotrófica Lateral/tratamento farmacológico , Colestenonas/uso terapêutico , Ciclosporina/uso terapêutico , Mitocôndrias/efeitos dos fármacos , Proteínas de Transporte da Membrana Mitocondrial/genética , Canal de Ânion 1 Dependente de Voltagem/genética , Esclerose Amiotrófica Lateral/genética , Esclerose Amiotrófica Lateral/metabolismo , Esclerose Amiotrófica Lateral/patologia , Ciclofilinas/genética , Ciclofilinas/metabolismo , Regulação da Expressão Gênica , Hexoquinase/genética , Hexoquinase/metabolismo , Humanos , Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/antagonistas & inibidores , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Membranas Mitocondriais/efeitos dos fármacos , Membranas Mitocondriais/metabolismo , ATPases Mitocondriais Próton-Translocadoras/antagonistas & inibidores , ATPases Mitocondriais Próton-Translocadoras/genética , ATPases Mitocondriais Próton-Translocadoras/metabolismo , Neoplasias/tratamento farmacológico , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patologia , Doenças Neurodegenerativas/tratamento farmacológico , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Doenças do Sistema Nervoso Periférico/tratamento farmacológico , Doenças do Sistema Nervoso Periférico/genética , Doenças do Sistema Nervoso Periférico/metabolismo , Doenças do Sistema Nervoso Periférico/patologia , Permeabilidade/efeitos dos fármacos , Ligação Proteica , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Tubulina (Proteína)/genética , Tubulina (Proteína)/metabolismo , Canal de Ânion 1 Dependente de Voltagem/antagonistas & inibidores , Canal de Ânion 1 Dependente de Voltagem/metabolismo
13.
BMC Med Genet ; 21(1): 77, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-32293312

RESUMO

BACKGROUND: Myopathy with extrapyramidal signs (MPXPS) is an autosomal recessive mitochondrial disorder which is caused by mutation in mitochondrial calcium uptake 1 (MICU1) gene located on chromosome 10q22.1. Next Generation Sequencing (NGS) technology is the most effective method for identification of pathogenic variants with the ability to overcome some limitations which Sanger sequencing may encountered. There are few reports on this rare disease around the world and here in this study we first revealed genetic identification of two affected individuals in an Iranian family with a novel mutation. CASE PRESENTATION: The proband was a 5-year-old girl from consanguenous parents. She was first clinically suspicious of affected with limb-girdle muscular dystrophy (LGMD). Muscle biopsy studies and autozygosity mapping, using four short tandem repeat (STR) markers linked to 6 genes of the most prevalent forms of LGMD, ruled out calpainopathy, dysferlinopathy, and sarcoglycanopathis. DNA sample of the proband was sent for NGS. Whole exome sequencing (WES) revealed a novel mutation c.1295delA in exon 13 of MICU1 gene. This homozygous deletion creates a frameshift and a premature stop codon downstream of canonical EF4 calcium binding motif of MICU1. According to the American College of Medical Genetics and Genomics (ACMG) guidline for sequence interpretation, this variant was a pathogenic one. Sanger sequencing in all family members confirmed the results of the WES. CONCLUSIONS: This study was the first report of MPXPS in Iranian population which also revealed a novel mutation in the MICU1 gene.


Assuntos
Proteínas de Ligação ao Cálcio/genética , Proteínas de Transporte de Cátions/genética , Repetições de Microssatélites/genética , Proteínas de Transporte da Membrana Mitocondrial/genética , Doenças Musculares/genética , Distrofia Muscular do Cíngulo dos Membros/genética , Pré-Escolar , Exoma/genética , Éxons/genética , Tratos Extrapiramidais/metabolismo , Tratos Extrapiramidais/patologia , Feminino , Mutação da Fase de Leitura/genética , Sequenciamento de Nucleotídeos em Larga Escala , Homozigoto , Humanos , Irã (Geográfico)/epidemiologia , Doenças Musculares/patologia , Distrofia Muscular do Cíngulo dos Membros/patologia , Linhagem , Deleção de Sequência/genética , Sequenciamento Completo do Exoma
14.
PLoS One ; 15(3): e0230566, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32208444

RESUMO

A phenomenon of genetic compensation is commonly observed when an organism with a disease-bearing mutation shows incomplete penetrance of the disease phenotype. Such incomplete phenotypic penetrance, or genetic compensation, is more commonly found in stable knockout models, rather than transient knockdown models. As such, these incidents present a challenge for the disease modeling field, although a deeper understanding of genetic compensation may also hold the key for novel therapeutic interventions. In our study we created a knockout model of slc25a46 gene, which is a recently discovered important player in mitochondrial dynamics, and deleterious mutations in which are known to cause peripheral neuropathy, optic atrophy and cerebellar ataxia. We report a case of genetic compensation in a stable slc25a46 homozygous zebrafish mutant (hereafter referred as "mutant"), in contrast to a penetrant disease phenotype in the first generation (F0) slc25a46 mosaic mutant (hereafter referred as "crispant"), generated with CRISPR/Cas-9 technology. We show that the crispant phenotype is specific and rescuable. By performing mRNA sequencing, we define significant changes in slc25a46 mutant's gene expression profile, which are largely absent in crispants. We find that among the most significantly altered mRNAs, anxa6 gene stands out as a functionally relevant player in mitochondrial dynamics. We also find that our genetic compensation case does not arise from mechanisms driven by mutant mRNA decay. Our study contributes to the growing evidence of the genetic compensation phenomenon and presents novel insights about Slc25a46 function. Furthermore, our study provides the evidence for the efficiency of F0 CRISPR screens for disease candidate genes, which may be used to advance the field of functional genetics.


Assuntos
Sistemas CRISPR-Cas , Proteínas de Transporte da Membrana Mitocondrial/genética , Proteínas de Peixe-Zebra/genética , Peixe-Zebra/genética , Animais , Ataxia Cerebelar/genética , Modelos Animais de Doenças , Feminino , Marcação de Genes , Masculino , Mutagênese , Mutação , Atrofia Óptica/genética , Doenças do Sistema Nervoso Periférico/genética
15.
Cell ; 180(6): 1178-1197.e20, 2020 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-32200800

RESUMO

Social impairment is frequently associated with mitochondrial dysfunction and altered neurotransmission. Although mitochondrial function is crucial for brain homeostasis, it remains unknown whether mitochondrial disruption contributes to social behavioral deficits. Here, we show that Drosophila mutants in the homolog of the human CYFIP1, a gene linked to autism and schizophrenia, exhibit mitochondrial hyperactivity and altered group behavior. We identify the regulation of GABA availability by mitochondrial activity as a biologically relevant mechanism and demonstrate its contribution to social behavior. Specifically, increased mitochondrial activity causes gamma aminobutyric acid (GABA) sequestration in the mitochondria, reducing GABAergic signaling and resulting in social deficits. Pharmacological and genetic manipulation of mitochondrial activity or GABA signaling corrects the observed abnormalities. We identify Aralar as the mitochondrial transporter that sequesters GABA upon increased mitochondrial activity. This study increases our understanding of how mitochondria modulate neuronal homeostasis and social behavior under physiopathological conditions.


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Drosophila/metabolismo , Mitocôndrias/metabolismo , Ácido gama-Aminobutírico/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Animais Geneticamente Modificados , Ácido Aspártico/metabolismo , Cálcio/metabolismo , Proteínas de Ligação ao Cálcio/fisiologia , Proteínas de Drosophila/fisiologia , Drosophila melanogaster/metabolismo , Glucose/metabolismo , Homeostase , Humanos , Masculino , Mitocôndrias/genética , Proteínas de Transporte da Membrana Mitocondrial/genética , Proteínas Mitocondriais/metabolismo , Neurônios/metabolismo , Comportamento Social , Transmissão Sináptica , Ácido gama-Aminobutírico/genética
16.
Biochim Biophys Acta Mol Basis Dis ; 1866(6): 165746, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32105825

RESUMO

In the mitochondria of healthy cells, Apoptosis-Inducing factor (AIF) is required for the optimal functioning of the respiratory chain machinery, mitochondrial integrity, cell survival, and proliferation. In all analysed species, it was revealed that the downregulation or depletion of AIF provokes mainly the post-transcriptional loss of respiratory chain Complex I protein subunits. Recent progress in the field has revealed that AIF fulfils its mitochondrial pro-survival function by interacting physically and functionally with CHCHD4, the evolutionarily-conserved human homolog of yeast Mia40. The redox-regulated CHCHD4/Mia40-dependent import machinery operates in the intermembrane space of the mitochondrion and controls the import of a set of nuclear-encoded cysteine-motif carrying protein substrates. In addition to their participation in the biogenesis of specific respiratory chain protein subunits, CHCHD4/Mia40 substrates are also implicated in the control of redox regulation, antioxidant response, translation, lipid homeostasis and mitochondrial ultrastructure and dynamics. Here, we discuss recent insights on the AIF/CHCHD4-dependent protein import pathway and review current data concerning the CHCHD4/Mia40 protein substrates in metazoan. Recent findings and the identification of disease-associated mutations in AIF or in specific CHCHD4/Mia40 substrates have highlighted these proteins as potential therapeutic targets in a variety of human disorders.


Assuntos
Fator de Indução de Apoptose/genética , Complexo I de Transporte de Elétrons/genética , Mitocôndrias/genética , Proteínas de Transporte da Membrana Mitocondrial/genética , Fator de Indução de Apoptose/metabolismo , Cisteína/genética , Cisteína/metabolismo , Dissulfetos/metabolismo , Complexo I de Transporte de Elétrons/metabolismo , Regulação da Expressão Gênica , Humanos , Mitocôndrias/metabolismo , Proteínas Mitocondriais/genética , Mutação/genética , Transporte Proteico/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo
17.
J Hum Genet ; 65(3): 231-240, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31907385

RESUMO

TOM70 is a member of the TOM complex that transports cytosolic proteins into mitochondria. Here, we identified two compound heterozygous variants in TOMM70 [c.794C>T (p.T265M) and c.1745C>T (p.A582V)] from a patient with severe anemia, lactic acidosis, and developmental delay. Patient-derived immortalized lymphocytes showed decreased TOM70 expression, oligomerized TOM70 complex, and TOM 20/22/40 complex compared with expression in control lymphocytes. Functional analysis revealed that patient-derived cells exhibited multi-oxidative phosphorylation system (OXPHOS) complex defects, with complex IV being primarily affected. As a result, patient-derived cells grew slower in galactose medium and generated less ATP and more extracellular lactic acid than did control cells. In vitro cell model compensatory experiments confirmed the pathogenicity of TOMM70 variants since only wild-type TOM70, but not mutant TOM70, could restore the complex IV defect and TOM70 expression in TOM70 knockdown U2OS cells. Altogether, we report the first case of mitochondrial disease-causing mutations in TOMM70 and demonstrate that TOM70 is essential for multi-OXPHOS assembly. Mutational screening of TOMM70 should be employed to identify mitochondrial disease-causing gene mutations in the future.


Assuntos
Acidose Láctica/genética , Anemia/genética , Deficiências do Desenvolvimento/genética , Proteínas de Transporte da Membrana Mitocondrial/genética , Acidose Láctica/patologia , Anemia/patologia , Criança , Deficiências do Desenvolvimento/patologia , Humanos , Masculino , Mitocôndrias/genética , Doenças Mitocondriais/genética , Doenças Mitocondriais/patologia , Mutação/genética , Fosforilação Oxidativa , Sequenciamento Completo do Exoma
18.
Nat Commun ; 11(1): 433, 2020 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-31974380

RESUMO

Ferroptosis is a newly defined form of regulated cell death characterized by the iron-dependent accumulation of lipid hydroperoxides. Erastin, the ferroptosis activator, binds to voltage-dependent anion channels VDAC2 and VDCA3, but treatment with erastin can result in the degradation of the channels. Here, the authors show that Nedd4 is induced following erastin treatment, which leads to the ubiquitination and subsequent degradation of the channels. Depletion of Nedd4 limits the protein degradation of VDAC2/3, which increases the sensitivity of cancer cells to erastin. By understanding the molecular mechanism of erastin-induced cellular resistance, we can discover how cells adapt to new molecules to maintain homeostasis. Furthermore, erastin-induced resistance mediated by FOXM1-Nedd4-VDAC2/3 negative feedback loop provides an initial framework for creating avenues to overcome the drug resistance of ferroptosis activators.


Assuntos
Antineoplásicos/farmacologia , Melanoma/tratamento farmacológico , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Ubiquitina-Proteína Ligases Nedd4/metabolismo , Piperazinas/farmacologia , Canal de Ânion 2 Dependente de Voltagem/metabolismo , Canais de Ânion Dependentes de Voltagem/metabolismo , Animais , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/fisiologia , Feminino , Ferroptose/efeitos dos fármacos , Ferroptose/fisiologia , Proteína Forkhead Box M1/metabolismo , Humanos , Melanoma/metabolismo , Melanoma/patologia , Camundongos Nus , Proteínas de Transporte da Membrana Mitocondrial/genética , Ubiquitina-Proteína Ligases Nedd4/genética , Ubiquitinação/efeitos dos fármacos , Canal de Ânion 2 Dependente de Voltagem/genética , Canais de Ânion Dependentes de Voltagem/genética , Ensaios Antitumorais Modelo de Xenoenxerto
19.
Proc Natl Acad Sci U S A ; 117(5): 2519-2525, 2020 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-31964807

RESUMO

The highly conserved COP9 signalosome (CSN), composed of 8 subunits (Cops1 to Cops8), has been implicated in pluripotency maintenance of human embryonic stem cells (ESCs). Yet, the mechanism for the CSN to regulate pluripotency remains elusive. We previously showed that Cops2, independent of the CSN, is essential for the pluripotency maintenance of mouse ESCs. In this study, we set out to investigate how Cops5 and Cops8 regulate ESC differentiation and tried to establish Cops5 and Cops8 knockout (KO) ESC lines by CRISPR/Cas9. To our surprise, no Cops5 KO ESC clones were identified out of 127 clones, while three Cops8 KO ESC lines were established out of 70 clones. We then constructed an inducible Cops5 KO ESC line. Cops5 KO leads to decreased expression of the pluripotency marker Nanog, proliferation defect, G2/M cell-cycle arrest, and apoptosis of ESCs. Further analysis revealed dual roles of Cops5 in maintaining genomic stability of ESCs. On one hand, Cops5 suppresses the autophagic degradation of Mtch2 to direct cellular metabolism toward glycolysis and minimize reactive oxygen species (ROS) production, thereby reducing endogenous DNA damage. On the other hand, Cops5 is required for high DNA damage repair (DDR) activities in ESCs. Without Cops5, elevated ROS and reduced DDR activities lead to DNA damage accumulation in ESCs. Subsequently, p53 is activated to trigger G2/M arrest and apoptosis. Altogether, our studies reveal an essential role of Cops5 in maintaining genome integrity and self-renewal of ESCs by regulating cellular metabolism and DDR pathways.


Assuntos
Complexo do Signalossomo COP9/metabolismo , Reparo do DNA , Células-Tronco Embrionárias/enzimologia , Instabilidade Genômica , Peptídeo Hidrolases/metabolismo , Animais , Apoptose , Complexo do Signalossomo COP9/genética , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Diferenciação Celular , Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/metabolismo , Pontos de Checagem da Fase G2 do Ciclo Celular , Técnicas de Inativação de Genes , Camundongos , Proteínas de Transporte da Membrana Mitocondrial/genética , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Fosforilação Oxidativa , Peptídeo Hidrolases/genética , Espécies Reativas de Oxigênio/metabolismo
20.
Clin Sci (Lond) ; 134(2): 239-259, 2020 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-31943002

RESUMO

Mitochondrial stress has been widely observed in diabetic kidney disease (DKD). Cyclophilin D (CypD) is a functional component of the mitochondrial permeability transition pore (mPTP) which allows the exchange of ions and solutes between the mitochondrial matrix to induce mitochondrial swelling and activation of cell death pathways. CypD has been successfully targeted in other disease contexts to improve mitochondrial function and reduced pathology. Two approaches were used to elucidate the role of CypD and the mPTP in DKD. Firstly, mice with a deletion of the gene encoding CypD (Ppif-/-) were rendered diabetic with streptozotocin (STZ) and followed for 24 weeks. Secondly, Alisporivir, a CypD inhibitor was administered to the db/db mouse model (5 mg/kg/day oral gavage for 16 weeks). Ppif-/- mice were not protected against diabetes-induced albuminuria and had greater glomerulosclerosis than their WT diabetic littermates. Renal hyperfiltration was lower in diabetic Ppif-/- as compared with WT mice. Similarly, Alisporivir did not improve renal function nor pathology in db/db mice as assessed by no change in albuminuria, KIM-1 excretion and glomerulosclerosis. Db/db mice exhibited changes in mitochondrial function, including elevated respiratory control ratio (RCR), reduced mitochondrial H2O2 generation and increased proximal tubular mitochondrial volume, but these were unaffected by Alisporivir treatment. Taken together, these studies indicate that CypD has a complex role in DKD and direct targeting of this component of the mPTP will likely not improve renal outcomes.


Assuntos
Ciclofilina D/metabolismo , Diabetes Mellitus Experimental/metabolismo , Nefropatias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Albuminúria/genética , Albuminúria/metabolismo , Animais , Ciclofilina D/antagonistas & inibidores , Ciclofilina D/genética , Ciclosporina/farmacologia , Diabetes Mellitus Experimental/genética , Nefropatias Diabéticas/genética , Nefropatias Diabéticas/metabolismo , Peróxido de Hidrogênio/metabolismo , Rim/efeitos dos fármacos , Rim/metabolismo , Rim/patologia , Nefropatias/genética , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/genética , ATPases Translocadoras de Prótons/metabolismo
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