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1.
Hum Mol Genet ; 31(24): 4121-4130, 2022 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-35913762

RESUMO

The high-affinity copper transporter CTR1 is encoded by CTR1 (SLC31A1), a gene locus for which no detailed genotype-phenotype correlations have previously been reported. We describe identical twin male infants homozygous for a novel missense variant NM_001859.4:c.284 G > A (p.Arg95His) in CTR1 with a distinctive autosomal recessive syndrome of infantile seizures and neurodegeneration, consistent with profound central nervous system copper deficiency. We used clinical, biochemical and molecular methods to delineate the first recognized examples of human CTR1 deficiency. These included clinical phenotyping, brain imaging, assays for copper, cytochrome c oxidase (CCO), and mitochondrial respiration, western blotting, cell transfection experiments, confocal and electron microscopy, protein structure modeling and fetal brain and cerebral organoid CTR1 transcriptome analyses. Comparison with two other critical mediators of cellular copper homeostasis, ATP7A and ATP7B, genes associated with Menkes disease and Wilson disease, respectively, revealed that expression of CTR1 was highest. Transcriptome analyses identified excitatory neurons and radial glia as brain cell types particularly enriched for copper transporter transcripts. We also assessed the effects of Copper Histidinate in the patients' cultured cells and in the patients, under a formal clinical protocol. Treatment normalized CCO activity and enhanced mitochondrial respiration in vitro, and was associated with modest clinical improvements. In combination with present and prior studies, these infants' clinical, biochemical and molecular phenotypes establish the impact of this novel variant on copper metabolism and cellular homeostasis and illuminate a crucial role for CTR1 in human brain development. CTR1 deficiency represents a newly defined inherited disorder of brain copper metabolism.


Assuntos
Transportador de Cobre 1 , Cobre , Doenças Neurodegenerativas , Convulsões , Humanos , Masculino , Cobre/metabolismo , Transportador de Cobre 1/genética , Gêmeos , Lactente , Mutação de Sentido Incorreto , Síndrome , Doenças Neurodegenerativas/diagnóstico , Doenças Neurodegenerativas/genética , Convulsões/diagnóstico , Convulsões/genética
2.
Hum Mol Genet ; 28(20): 3406-3421, 2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31373366

RESUMO

Gaucher disease (GD) is caused by GBA1 mutations leading to functional deficiency of acid-ß-glucosidase (GCase). No effective treatment is available for neuronopathic GD (nGD). A subclass of neural stem and precursor cells (NPCs) expresses VLA4 (integrin α4ß1, very late antigen-4) that facilitates NPC entry into the brain following intravenous (IV) infusion. Here, the therapeutic potential of IV VLA4+NPCs was assessed for nGD using wild-type mouse green fluorescent protein (GFP)-positive multipotent induced pluripotent stem cell (iPSC)-derived VLA4+NPCs. VLA4+NPCs successfully engrafted in the nGD (4L;C*) mouse brain. GFP-positive cells differentiated into neurons, astrocytes and oligodendrocytes in the brainstem, midbrain and thalamus of the transplanted mice and significantly improved sensorimotor function and prolonged life span compared to vehicle-treated 4L;C* mice. VLA4+NPC transplantation significantly decreased levels of CD68 and glial fibrillary acidic protein, as well as TNFα mRNA levels in the brain, indicating reduced neuroinflammation. Furthermore, decreased Fluoro-Jade C and NeuroSilver staining suggested inhibition of neurodegeneration. VLA4+NPC-engrafted 4L;C* midbrains showed 35% increased GCase activity, reduced substrate [glucosylceramide (GC, -34%) and glucosylsphingosine (GS, -11%)] levels and improved mitochondrial oxygen consumption rates in comparison to vehicle-4L;C* mice. VLA4+NPC engraftment in 4L;C* brain also led to enhanced expression of neurotrophic factors that have roles in neuronal survival and the promotion of neurogenesis. This study provides evidence that iPSC-derived NPC transplantation has efficacy in an nGD mouse model and provides proof of concept for autologous NPC therapy in nGD.


Assuntos
Doença de Gaucher/metabolismo , Doença de Gaucher/terapia , Glucosilceramidase/metabolismo , Células-Tronco Pluripotentes Induzidas/fisiologia , Células-Tronco Neurais/fisiologia , Animais , Terapia Baseada em Transplante de Células e Tecidos/métodos , Células-Tronco Pluripotentes Induzidas/citologia , Infusões Intravenosas , Integrina alfa4beta1/metabolismo , Camundongos , Células-Tronco Neurais/citologia , beta-Glucosidase/metabolismo
3.
Hum Mol Genet ; 26(19): 3776-3791, 2017 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-28934388

RESUMO

Recently, we identified biallelic mutations of SLC25A46 in patients with multiple neuropathies. Functional studies revealed that SLC25A46 may play an important role in mitochondrial dynamics by mediating mitochondrial fission. However, the cellular basis and pathogenic mechanism of the SLC25A46-related neuropathies are not fully understood. Thus, we generated a Slc25a46 knock-out mouse model. Mice lacking SLC25A46 displayed severe ataxia, mainly caused by degeneration of Purkinje cells. Increased numbers of small, unmyelinated and degenerated optic nerves as well as loss of retinal ganglion cells indicated optic atrophy. Compound muscle action potentials in peripheral nerves showed peripheral neuropathy associated with degeneration and demyelination in axons. Mutant cerebellar neurons have large mitochondria, which exhibit abnormal distribution and transport. Biochemically mutant mice showed impaired electron transport chain activity and accumulated autophagy markers. Our results suggest that loss of SLC25A46 causes degeneration in neurons by affecting mitochondrial dynamics and energy production.


Assuntos
Mitocôndrias/genética , Mitocôndrias/metabolismo , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Proteínas de Transporte de Fosfato/genética , Proteínas de Transporte de Fosfato/metabolismo , Animais , Ataxia/patologia , Feminino , Humanos , Masculino , Camundongos , Camundongos Knockout , Dinâmica Mitocondrial/fisiologia , Mutação , Células Ganglionares da Retina/patologia
4.
Hum Mol Genet ; 26(24): 4937-4950, 2017 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-29040572

RESUMO

Iron-sulfur (Fe-S) clusters are ubiquitous cofactors essential to various cellular processes, including mitochondrial respiration, DNA repair, and iron homeostasis. A steadily increasing number of disorders are being associated with disrupted biogenesis of Fe-S clusters. Here, we conducted whole-exome sequencing of patients with optic atrophy and other neurological signs of mitochondriopathy and identified 17 individuals from 13 unrelated families with recessive mutations in FDXR, encoding the mitochondrial membrane-associated flavoprotein ferrodoxin reductase required for electron transport from NADPH to cytochrome P450. In vitro enzymatic assays in patient fibroblast cells showed deficient ferredoxin NADP reductase activity and mitochondrial dysfunction evidenced by low oxygen consumption rates (OCRs), complex activities, ATP production and increased reactive oxygen species (ROS). Such defects were rescued by overexpression of wild-type FDXR. Moreover, we found that mice carrying a spontaneous mutation allelic to the most common mutation found in patients displayed progressive gait abnormalities and vision loss, in addition to biochemical defects consistent with the major clinical features of the disease. Taken together, these data provide the first demonstration that germline, hypomorphic mutations in FDXR cause a novel mitochondriopathy and optic atrophy in humans.


Assuntos
Ferredoxinas/genética , Atrofia Óptica/genética , Sulfito Redutase (Ferredoxina)/genética , Adolescente , Alelos , Animais , Criança , Pré-Escolar , Transporte de Elétrons , Feminino , Ferredoxinas/metabolismo , Humanos , Lactente , Ferro/metabolismo , Proteínas Ferro-Enxofre/genética , Masculino , Camundongos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Mutagênese , Mutação , Oxirredutases/genética , Oxirredutases/metabolismo , Linhagem , Sulfito Redutase (Ferredoxina)/metabolismo , Sequenciamento do Exoma/métodos
5.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 36(11): 1130-1132, 2019 Nov 10.
Artigo em Zh | MEDLINE | ID: mdl-31703143

RESUMO

OBJECTIVE: To analyze the hematological characteristics of a patient with Hb Ottawa in conjunction with ß -thalassemia. METHODS: Peripheral blood samples from the proband and her parents were collected and subjected to red blood cell analysis and hemoglobin electrophoresis. Genotypes of α - and ß -globin genes were also analyzed. RESULTS: The proband and her mother were both heterozygotes for Hb Ottawa and ß -thalassemia variant IVS II-654, and presented with typical ß -thalassemia trait featuring hypochromic microcytic anemia. An abnormal hemoglobin band was detected upon electrophoresis. CONCLUSION: Co-existence of Hb Ottawa and ß -thalassemia may not aggravate the phenotype.


Assuntos
Hemoglobinas Anormais/genética , Talassemia beta/genética , Feminino , Testes Genéticos , Heterozigoto , Humanos , alfa-Globinas/genética , Globinas beta/genética
6.
J Biol Chem ; 292(7): 2881-2892, 2017 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-28049726

RESUMO

Nuclear modifier gene(s) was proposed to modulate the phenotypic expression of mitochondrial DNA mutation(s). Our previous investigations revealed that a nuclear modifier allele (A10S) in TRMU (methylaminomethyl-2-thiouridylate-methyltransferase) related to tRNA modification interacts with 12S rRNA 1555A→G mutation to cause deafness. The A10S mutation resided at a highly conserved residue of the N-terminal sequence. It was hypothesized that the A10S mutation altered the structure and function of TRMU, thereby causing mitochondrial dysfunction. Using molecular dynamics simulations, we showed that the A10S mutation introduced the Ser10 dynamic electrostatic interaction with the Lys106 residue of helix 4 within the catalytic domain of TRMU. The Western blotting analysis displayed the reduced levels of TRMU in mutant cells carrying the A10S mutation. The thermal shift assay revealed the Tm value of mutant TRMU protein, lower than that of the wild-type counterpart. The A10S mutation caused marked decreases in 2-thiouridine modification of U34 of tRNALys, tRNAGlu and tRNAGln However, the A10S mutation mildly increased the aminoacylated efficiency of tRNAs. The altered 2-thiouridine modification worsened the impairment of mitochondrial translation associated with the m.1555A→G mutation. The defective translation resulted in the reduced activities of mitochondrial respiration chains. The respiratory deficiency caused the reduction of mitochondrial ATP production and elevated the production of reactive oxidative species. As a result, mutated TRMU worsened mitochondrial dysfunctions associated with m.1555A→G mutation, exceeding the threshold for expressing a deafness phenotype. Our findings provided new insights into the pathophysiology of maternally inherited deafness that was manifested by interaction between mtDNA mutation and nuclear modifier gene.


Assuntos
Alelos , Surdez/genética , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Mutação , Fenótipo , RNA Ribossômico/genética , RNA de Transferência/metabolismo , tRNA Metiltransferases/metabolismo , Aminoacilação , Estabilidade Enzimática , Fluorometria , Humanos , Proteínas Mitocondriais/genética , Simulação de Dinâmica Molecular , tRNA Metiltransferases/genética
7.
Hum Mol Genet ; 25(23): 5126-5141, 2016 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-27655403

RESUMO

Neuronopathic Gaucher disease (nGD) manifests as severe neurological symptoms in patients with no effective treatment available. Ryanodine receptors (Ryrs) are a family of calcium release channels on intracellular stores. The goal of this study is to determine if Ryrs are potential targets for nGD treatment. A nGD cell model (CBE-N2a) was created by inhibiting acid ß-glucosidase (GCase) in N2a cells with conduritol B epoxide (CBE). Enhanced cytosolic calcium in CBE-N2a cells was blocked by either ryanodine or dantrolene, antagonists of Ryrs and by Genz-161, a glucosylceramide synthase inhibitor, suggesting substrate-mediated ER-calcium efflux occurs through ryanodine receptors. In the brain of a nGD (4L;C*) mouse model, expression of Ryrs was normal at 13 days of age, but significantly decreased below the wild type level in end-stage 4L;C* brains at 40 days. Treatment with dantrolene in 4L;C* mice starting at postnatal day 5 delayed neurological pathology and prolonged survival. Compared to untreated 4L;C* mice, dantrolene treatment significantly improved gait, reduced LC3-II levels, improved mitochondrial ATP production and reduced inflammation in the brain. Dantrolene treatment partially normalized Ryr expression and its potential regulators, CAMK IV and calmodulin. Furthermore, dantrolene treatment increased residual mutant GCase activity in 4L;C* brains. These data demonstrate that modulating Ryrs has neuroprotective effects in nGD through mechanisms that protect the mitochondria, autophagy, Ryr expression and enhance GCase activity. This study suggests that calcium signalling stabilization, e.g. with dantrolene, could be a potential disease modifying therapy for nGD.


Assuntos
Dantroleno/administração & dosagem , Doença de Gaucher/tratamento farmacológico , Mitocôndrias/efeitos dos fármacos , Canal de Liberação de Cálcio do Receptor de Rianodina/genética , Animais , Sinalização do Cálcio/genética , Modelos Animais de Doenças , Doença de Gaucher/genética , Doença de Gaucher/fisiopatologia , Humanos , Camundongos , Mitocôndrias/genética , Mitocôndrias/patologia , Neurônios/efeitos dos fármacos , Neurônios/patologia , Fármacos Neuroprotetores/administração & dosagem , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo
8.
Hum Mol Genet ; 25(3): 584-96, 2016 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-26647310

RESUMO

Leber's hereditary optic neuropathy (LHON) is the most common mitochondrial disorder. Nuclear modifier genes are proposed to modify the phenotypic expression of LHON-associated mitochondrial DNA (mtDNA) mutations. By using an exome sequencing approach, we identified a LHON susceptibility allele (c.572G>T, p.191Gly>Val) in YARS2 gene encoding mitochondrial tyrosyl-tRNA synthetase, which interacts with m.11778G>A mutation to cause visual failure. We performed functional assays by using lymphoblastoid cell lines derived from members of Chinese families (asymptomatic individuals carrying m.11778G>A mutation, or both m.11778G>A and heterozygous p.191Gly>Val mutations and symptomatic subjects harboring m.11778G>A and homozygous p.191Gly>Val mutations) and controls lacking these mutations. The 191Gly>Val mutation reduced the YARS2 protein level in the mutant cells. The aminoacylated efficiency and steady-state level of tRNA(Tyr) were markedly decreased in the cell lines derived from patients both carrying homozygous YARS2 p.191Gly>Val and m.11778G>A mutations. The failure in tRNA(Tyr) metabolism impaired mitochondrial translation, especially for polypeptides with high content of tyrosine codon such as ND4, ND5, ND6 and COX2 in cells lines carrying homozygous YARS2 p.191Gly>Val and m.11778G>A mutations. The YARS2 p.191Gly>Val mutation worsened the respiratory phenotypes associated with m.11778G>A mutation, especially reducing activities of complexes I and IV. The respiratory deficiency altered the efficiency of mitochondrial ATP synthesis and increased the production of reactive oxygen species. Thus, mutated YARS2 aggravates mitochondrial dysfunctions associated with the m.11778G>A mutation, exceeding the threshold for the expression of blindness phenotype. Our findings provided new insights into the pathophysiology of LHON that were manifested by interaction between mtDNA mutation and mutated nuclear-modifier YARS2.


Assuntos
DNA Mitocondrial/genética , Mitocôndrias/genética , Proteínas Mitocondriais/genética , Mutação , Atrofia Óptica Hereditária de Leber/genética , Tirosina-tRNA Ligase/genética , Alelos , Sequência de Bases , Estudos de Casos e Controles , Linhagem Celular , Ciclo-Oxigenase 2/genética , Ciclo-Oxigenase 2/metabolismo , DNA Mitocondrial/metabolismo , Complexo I de Transporte de Elétrons/genética , Complexo I de Transporte de Elétrons/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/genética , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Exoma , Regulação da Expressão Gênica , Predisposição Genética para Doença , Heterozigoto , Homozigoto , Humanos , Mitocôndrias/enzimologia , Mitocôndrias/patologia , Proteínas Mitocondriais/química , Proteínas Mitocondriais/metabolismo , Modelos Moleculares , Dados de Sequência Molecular , NADH Desidrogenase/genética , NADH Desidrogenase/metabolismo , Neurônios/enzimologia , Neurônios/patologia , Atrofia Óptica Hereditária de Leber/enzimologia , Atrofia Óptica Hereditária de Leber/patologia , Linhagem , Fenótipo , Tirosina-tRNA Ligase/química , Tirosina-tRNA Ligase/metabolismo
9.
J Hum Genet ; 63(12): 1211-1222, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30250212

RESUMO

Mitochondrial dysfunction lies behind many neurodegenerative disorders, owing largely to the intense energy requirements of most neurons. Such mitochondrial dysfunction may work through a variety of mechanisms, from direct disruption of the electron transport chain to abnormal mitochondrial biogenesis. Recently, we have identified biallelic mutations in the mitochondrial flavoprotein "ferredoxin reductase" (FDXR) gene as a novel cause of mitochondriopathy, peripheral neuropathy, and optic atrophy. In this report, we expand upon those results by describing two new cases of disease-causing FDXR variants in patients with variable severity of phenotypes, including evidence of an inflammatory response in brain autopsy. To investigate the underlying pathogenesis, we examined neurodegeneration in a mouse model. We found that Fdxr mutant mouse brain tissues share pathological changes similar to those seen in patient autopsy material, including increased astrocytes. Furthermore, we show that these abnormalities are associated with increased levels of markers for both neurodegeneration and gliosis, with the latter implying inflammation as a major factor in the pathology of Fdxr mutations. These data provide further insight into the pathogenic mechanism of FDXR-mediated central neuropathy, and suggest an avenue for mechanistic studies that will ultimately inform treatment.


Assuntos
Alelos , Proteínas Ferro-Enxofre/genética , Mutação , Doenças Neurodegenerativas/genética , Oxirredutases/genética , Animais , Encéfalo/enzimologia , Encéfalo/patologia , Feminino , Humanos , Inflamação/enzimologia , Inflamação/genética , Inflamação/patologia , Proteínas Ferro-Enxofre/metabolismo , Masculino , Camundongos , Camundongos Transgênicos , Doenças Neurodegenerativas/enzimologia , Doenças Neurodegenerativas/patologia , Oxirredutases/metabolismo
10.
Nucleic Acids Res ; 44(22): 10974-10985, 2016 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-27536005

RESUMO

In this report, we investigated the pathogenic mechanism underlying the deafness-associated mitochondrial(mt) tRNAAsp 7551A > G mutation. The m.7551A > G mutation is localized at a highly conserved nucleotide(A37), adjacent (3') to the anticodon, which is important for the fidelity of codon recognition and stabilization in functional tRNAs. It was anticipated that the m.7551A > G mutation altered the structure and function of mt-tRNAAsp The primer extension assay demonstrated that the m.7551A > G mutation created the m1G37 modification of mt-tRNAAsp Using cybrid cell lines generated by transferring mitochondria from lymphoblastoid cell lines derived from a Chinese family into mitochondrial DNA(mtDNA)-less (ρo) cells, we demonstrated the significant decreases in the efficiency of aminoacylation and steady-state level of mt-tRNAAsp in mutant cybrids, compared with control cybrids. A failure in metabolism of mt-tRNAAsp caused the variable reductions in mtDNA-encoded polypeptides in mutant cybrids. Impaired mitochondrial translation led to the respiratory phenotype in mutant cybrids. The respiratory deficiency lowed mitochondrial adenosine triphosphate production and increased the production of oxidative reactive species in mutant cybrids. Our data demonstrated that mitochondrial dysfunctions caused by the m.7551A > G mutation are associated with deafness. Our findings may provide new insights into the pathophysiology of maternally transmitted deafness that was manifested by altered nucleotide modification of mitochondrial tRNA.


Assuntos
Surdez/genética , Mitocôndrias/genética , RNA de Transferência de Ácido Aspártico/genética , Linhagem Celular , Estudos de Associação Genética , Humanos , Masculino , Potencial da Membrana Mitocondrial , Linhagem , Mutação Puntual , Estabilidade de RNA , Espécies Reativas de Oxigênio/metabolismo , Adulto Jovem
11.
Hum Mol Genet ; 24(24): 7031-48, 2015 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26420838

RESUMO

Defective lysosomal acid ß-glucosidase (GCase) in Gaucher disease causes accumulation of glucosylceramide (GC) and glucosylsphingosine (GS) that distress cellular functions. To study novel pathological mechanisms in neuronopathic Gaucher disease (nGD), a mouse model (4L;C*), an analogue to subacute human nGD, was investigated for global profiles of differentially expressed brain mRNAs (DEGs) and miRNAs (DEmiRs). 4L;C* mice displayed accumulation of GC and GS, activated microglial cells, reduced number of neurons and aberrant mitochondrial function in the brain followed by deterioration in motor function. DEGs and DEmiRs were characterized from sequencing of mRNA and miRNA from cerebral cortex, brain stem, midbrain and cerebellum of 4L;C* mice. Gene ontology enrichment and pathway analysis showed preferential mitochondrial dysfunction in midbrain and uniform inflammatory response and identified novel pathways, axonal guidance signaling, synaptic transmission, eIF2 and mammalian target of rapamycin (mTOR) signaling potentially involved in nGD. Similar analyses were performed with mice treated with isofagomine (IFG), a pharmacologic chaperone for GCase. IFG treatment did not alter the GS and GC accumulation significantly but attenuated the progression of the disease and altered numerous DEmiRs and target DEGs to their respective normal levels in inflammation, mitochondrial function and axonal guidance pathways, suggesting its regulation on miRNA and the associated mRNA that underlie the neurodegeneration in nGD. These analyses demonstrate that the neurodegenerative phenotype in 4L;C* mice was associated with dysregulation of brain mRNAs and miRNAs in axonal guidance, synaptic plasticity, mitochondria function, eIF2 and mTOR signaling and inflammation and provides new insights for the nGD pathological mechanism.


Assuntos
Encéfalo/metabolismo , Doença de Gaucher/genética , Imino Piranoses/uso terapêutico , MicroRNAs/metabolismo , Chaperonas Moleculares/uso terapêutico , RNA Mensageiro/metabolismo , Animais , Axônios/metabolismo , Encéfalo/patologia , Modelos Animais de Doenças , Encefalite/metabolismo , Encefalite/patologia , Fator de Iniciação 2 em Eucariotos/metabolismo , Doença de Gaucher/tratamento farmacológico , Doença de Gaucher/metabolismo , Doença de Gaucher/patologia , Perfilação da Expressão Gênica , Glucosilceramidas/metabolismo , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismo , Chaperonas Moleculares/metabolismo , Neuroglia/patologia , Neurônios/patologia , Fenótipo , Psicosina/análogos & derivados , Psicosina/metabolismo , Transdução de Sinais , Transmissão Sináptica , Serina-Treonina Quinases TOR/metabolismo
12.
Biochem Biophys Res Commun ; 482(4): 632-637, 2017 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-27864145

RESUMO

Myeloid differentiation factor 88 (MyD88) plays a central role in innate immunity response, however, how its activity is tightly regulated remains largely unknown. In this study, we identify MyD88 as a novel substrate of NEDD8, and demonstrate that MyD88 NEDDylation antagonizes its ubiquitination. Interestingly, in response to the stimulation of IL-1ß, MyD88 NEDDylation is downregulated while its ubiquitination is upregulated. We also show that deNEDDylase NEDP1 serves as a regulator of this process. Furthermore, we demonstrate that NEDD8 negatively regulates the dimerization of MyD88 and suppresses MyD88-dependent NF-κB signaling. Taken together, this study reveals that NEDDylation of MyD88 regulates NF-κB activity through antagonizing its ubiquitination, suggesting a novel mechanism of modulating NF-κB signaling pathway.


Assuntos
Fator 88 de Diferenciação Mieloide/imunologia , NF-kappa B/imunologia , Ubiquitinação , Ubiquitinas/imunologia , Endopeptidases/imunologia , Células HEK293 , Humanos , Imunidade Inata , Interleucina-1beta/imunologia , Proteína NEDD8 , Transdução de Sinais
13.
PLoS Pathog ; 10(4): e1004041, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24763515

RESUMO

RIG-I like receptors (RLRs) recognize cytosolic viral RNA and initiate innate immunity; they increase the production of type I interferon (IFN) and the transcription of a series of antiviral genes to protect the host organism. Accurate regulation of the RLR pathway is important for avoiding tissue injury induced by excessive immune response. HSCARG is a newly reported negative regulator of NF-κB. Here we demonstrated that HSCARG participates in innate immunity. HSCARG inhibited the cellular antiviral response in an NF-κB independent manner, whereas deficiency of HSCARG had an opposite effect. After viral infection, HSCARG interacted with tumor necrosis receptor-associated factor 3 (TRAF3) and inhibited its ubiquitination by promoting the recruitment of OTUB1 to TRAF3. Knockout of HSCARG attenuated the de-ubiquitination of TRAF3 by OTUB1, and knockdown of OTUB1 abolished the effect of HSCARG. HSCARG also interacted with Ikappa-B kinase epsilon (IKKε) after viral infection and impaired the association between TRAF3 and IKKε, which further decreased the phosphorylation of IKKε and interferon response factor 3 (IRF3), thus suppressed the dimerization and nuclear translocation of IRF3. Moreover, knockdown of TRAF3 dampened the inhibitory effect of IFN-ß transcription by HSCARG, suggesting that TRAF3 is necessary for HSCARG to down-regulate RLR pathway. This study demonstrated that HSCARG is a negative regulator that enables balanced antiviral innate immunity.


Assuntos
Cisteína Endopeptidases/metabolismo , RNA Helicases DEAD-box/metabolismo , RNA Viral/metabolismo , Transdução de Sinais/fisiologia , Fator 3 Associado a Receptor de TNF/metabolismo , Fatores de Transcrição/metabolismo , Ubiquitinação/fisiologia , Linhagem Celular Tumoral , Cisteína Endopeptidases/genética , Cisteína Endopeptidases/imunologia , Proteína DEAD-box 58 , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/imunologia , Enzimas Desubiquitinantes , Técnicas de Silenciamento de Genes , Humanos , Quinase I-kappa B/genética , Quinase I-kappa B/imunologia , Quinase I-kappa B/metabolismo , Imunidade Inata , Infecções por Vírus de RNA/genética , Infecções por Vírus de RNA/imunologia , Infecções por Vírus de RNA/metabolismo , Vírus de RNA/genética , Vírus de RNA/imunologia , Vírus de RNA/metabolismo , RNA Viral/genética , RNA Viral/imunologia , Receptores Imunológicos , Fator 3 Associado a Receptor de TNF/genética , Fator 3 Associado a Receptor de TNF/imunologia , Fatores de Transcrição/genética , Fatores de Transcrição/imunologia
14.
Nucleic Acids Res ; 42(12): 8039-48, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24920829

RESUMO

In this report, we investigated the molecular genetic mechanism underlying the deafness-associated mitochondrial tRNAHis 12201T>C mutation. The destabilization of a highly conserved base-pairing (5A-68U) by the m.12201T>C mutation alters structure and function of tRNAHis. Using cybrids constructed by transferring mitochondria from lymphoblastoid cell lines derived from a Chinese family into mtDNA-less (ρo) cells, we showed ∼70% decrease in the steady-state level of tRNAHis in mutant cybrids, compared with control cybrids. The mutation changed the conformation of tRNAHis, as suggested by slower electrophoretic mobility of mutated tRNA with respect to the wild-type molecule. However, ∼60% increase in aminoacylated level of tRNAHis was observed in mutant cells. The failure in tRNAHis metabolism was responsible for the variable reductions in seven mtDNA-encoded polypeptides in mutant cells, ranging from 37 to 81%, with the average of ∼46% reduction, as compared with those of control cells. The impaired mitochondrial translation caused defects in respiratory capacity in mutant cells. Furthermore, marked decreases in the levels of mitochondrial ATP and membrane potential were observed in mutant cells. These mitochondrial dysfunctions caused an increase in the production of reactive oxygen species in the mutant cells. The data provide the evidence for a mitochondrial tRNAHis mutation leading to deafness.


Assuntos
Surdez/genética , Potencial da Membrana Mitocondrial , Mitocôndrias/metabolismo , Mutação , RNA de Transferência de Histidina/genética , Espécies Reativas de Oxigênio/metabolismo , Trifosfato de Adenosina/biossíntese , Linhagem Celular , Respiração Celular , Humanos , Proteínas Mitocondriais/metabolismo , RNA de Transferência de Histidina/química , RNA de Transferência de Histidina/metabolismo , Aminoacilação de RNA de Transferência
16.
Traffic ; 13(6): 790-9, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22348310

RESUMO

HSCARG is a newly identified nuclear factor-κB (NF-κB) inhibitor that plays important roles in cell growth. Our previous study found that HSCARG could shuttle between the nucleus and cytoplasm by sensing the change in cellular redox states. To further investigate the mechanism of HSCARG translocation and its effect on the regulation of NF-κB activity, we identified a previously uncharacterized nuclear export signal (NES) at residues 272-278 of HSCARG that is required for its cytoplasmic translocation. This leucine-rich NES was found to be mediated by chromosome region maintenance 1. More importantly, accumulation of HSCARG in the nucleus occurred following a mutation in the NES or oxidative stress, which attenuated the inhibition of NF-κB by HSCARG. These results indicate that nucleocytoplasmic translocation of HSCARG plays an important role in fine-tuning NF-κB signaling.


Assuntos
Citoplasma/metabolismo , Regulação Neoplásica da Expressão Gênica , Carioferinas/fisiologia , NF-kappa B/metabolismo , Receptores Citoplasmáticos e Nucleares/fisiologia , Fatores de Transcrição/metabolismo , Transporte Ativo do Núcleo Celular , Núcleo Celular/metabolismo , Análise Mutacional de DNA , Células HEK293 , Células HeLa , Humanos , Carioferinas/metabolismo , Leucina/metabolismo , Microscopia de Fluorescência/métodos , Modelos Biológicos , Sinais de Exportação Nuclear , Oxirredução , Estresse Oxidativo , Receptores Citoplasmáticos e Nucleares/metabolismo , Transdução de Sinais , Proteína Exportina 1
17.
Parasit Vectors ; 17(1): 253, 2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38863074

RESUMO

BACKGROUND: Fleas are one of the most common and pervasive ectoparasites worldwide, comprising at least 2500 valid species. They are vectors of several disease-causing agents, such as Yersinia pestis. Despite their significance, however, the molecular genetics, biology, and phylogenetics of fleas remain poorly understood. METHODS: We sequenced, assembled, and annotated the complete mitochondrial (mt) genome of the rodent flea Nosopsyllus laeviceps using next-generation sequencing technology. Then we combined the new mitogenome generated here with mt genomic data available for 23 other flea species to perform comparative mitogenomics, nucleotide diversity, and evolutionary rate analysis. Subsequently, the phylogenetic relationship within the order Siphonaptera was explored using the Bayesian inference (BI) and maximum likelihood (ML) methods based on concentrated data for 13 mt protein-coding genes. RESULTS: The complete mt genome of the rodent flea N. laeviceps was 16,533 base pairs (bp) in a circular DNA molecule, containing 37 typical genes (13 protein-coding genes, 22 transfer RNA [tRNA] genes, and two ribosomal RNA [rRNA] genes) with one large non-coding region (NCR). Comparative analysis among the order Siphonaptera showed a stable gene order with no gene arrangement, and high AT content (76.71-83.21%) with an apparent negative AT and GC skew except in three fleas Aviostivalius klossi bispiniformis, Leptopsylla segnis, and Neopsylla specialis. Moreover, we found robust evidence that the cytochrome c oxidase subunit 1 (cox1) gene was the most conserved protein-coding gene (Pi = 0.15, non-synonymous/synonymous [Ka/Ks] ratio = 0.13) of fleas. Phylogenomic analysis conducted using two methods revealed different topologies, but both results strongly indicated that (i) the families Ceratophyllidae and Leptopsyllidae were paraphyletic and were the closest to each other, and (ii) the family Ctenophthalmidae was paraphyletic. CONCLUSIONS: In this study, we obtained a high-quality mt genome of the rodent flea N. laeviceps and performed comparative mitogenomics and phylogeny of the order Siphonaptera using the mt database. The results will enrich the mt genome data for fleas, lay a foundation for the phylogenetic analysis of fleas, and promote the evolutionary analysis of Siphonaptera.


Assuntos
Genoma Mitocondrial , Filogenia , Sifonápteros , Animais , Sifonápteros/genética , Sifonápteros/classificação , Genoma Mitocondrial/genética , Roedores , Sequenciamento de Nucleotídeos em Larga Escala , RNA de Transferência/genética
18.
Cogn Neurodyn ; 18(1): 37-47, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38406198

RESUMO

Birds have developed visual cognitions, especially in discriminating colors due to their four types of cones in the retina. The entopallium of birds is thought to be involved in the processing of color information during visual cognition. However, there is a lack of understanding about how functional connectivity in the entopallium region of birds changes during color cognition, which is related to various input colors. We therefore trained pigeons to perform a delayed color matching task, in which two colors were randomly presented in sample stimuli phrases, and the neural activity at individual recording site and the gamma band functional connectivity among local population in entopallium during sample presentation were analyzed. Both gamma band energy and gamma band functional connectivity presented dynamics as the stimulus was presented and persisted. The response features in the early-stimulus phase were significantly different from those of baseline and the late-stimulus phase. Furthermore, gamma band energy showed significant differences between different colors during the early-stimulus phase, but the global feature of the gamma band functional network did not. Further decoding results showed that decoding accuracy was significantly enhanced by adding functional connectivity features, suggesting the global feature of the gamma band functional network did not directly contain color information, but was related to it. These results provided insight into information processing rules among local neuronal populations in the entopallium of birds during color cognition, which is important for their daily life.

20.
Interact J Med Res ; 13: e50047, 2024 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-39110502

RESUMO

BACKGROUND: The rehabilitation of children with disabilities has received considerable attention from the United Nations. However, the state of rehabilitation services for children with disabilities worldwide remains far from optimistic, even in economically affluent middle- and high-income countries. OBJECTIVE: This scoping review aimed to identify the rehabilitation needs of children with disabilities and their barriers to rehabilitation services in middle- and high-income countries. METHODS: A systematic search was conducted using MEDLINE and Web of Science for papers published from January 2013 to December 2023. Studies were included if they were peer-reviewed, full-text articles related to children with disabilities, reporting on their access to rehabilitation services, and conducted in countries classified by the World Bank 2023 as middle- and high-income economies. Exclusion criteria included duplicates, unavailable full texts, and studies without distinct outcomes. A total of 27 studies were selected following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, focusing on children, their families, or service providers. RESULTS: The suitability, availability, and affordability of rehabilitation services were identified as the major needs and barriers for children with disabilities in middle- and high-income countries. This included communication barriers, a need for more personnel and facilities, and the stagnation and inadequacy of economic subsidies. CONCLUSIONS: Middle- and high-income countries have relatively well-established rehabilitation infrastructure and support systems. They are nevertheless insufficient for meeting the needs of children with disabilities. More attention should be paid to these issues to improve the well-being of children with disabilities. The data provided by this review can help raise awareness of rehabilitation needs and barriers at the policy level.

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