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1.
Nucleic Acids Res ; 47(16): 8720-8733, 2019 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-31276587

RESUMO

Expression of human mitochondrial DNA is indispensable for proper function of the oxidative phosphorylation machinery. The mitochondrial genome encodes 22 tRNAs, 2 rRNAs and 11 mRNAs and their post-transcriptional modification constitutes one of the key regulatory steps during mitochondrial gene expression. Cytosine-5 methylation (m5C) has been detected in mitochondrial transcriptome, however its biogenesis has not been investigated in details. Mammalian NOP2/Sun RNA Methyltransferase Family Member 2 (NSUN2) has been characterized as an RNA methyltransferase introducing m5C in nuclear-encoded tRNAs, mRNAs and microRNAs and associated with cell proliferation and differentiation, with pathogenic variants in NSUN2 being linked to neurodevelopmental disorders. Here we employ spatially restricted proximity labelling and immunodetection to demonstrate that NSUN2 is imported into the matrix of mammalian mitochondria. Using three genetic models for NSUN2 inactivation-knockout mice, patient-derived fibroblasts and CRISPR/Cas9 knockout in human cells-we show that NSUN2 is necessary for the generation of m5C at positions 48, 49 and 50 of several mammalian mitochondrial tRNAs. Finally, we show that inactivation of NSUN2 does not have a profound effect on mitochondrial tRNA stability and oxidative phosphorylation in differentiated cells. We discuss the importance of the newly discovered function of NSUN2 in the context of human disease.


Assuntos
5-Metilcitosina/metabolismo , Eczema/genética , Transtornos do Crescimento/genética , Deficiência Intelectual/genética , Metiltransferases/genética , Microcefalia/genética , Processamento Pós-Transcricional do RNA , RNA Mitocondrial/genética , RNA de Transferência/genética , Animais , Sistemas CRISPR-Cas , Eczema/metabolismo , Eczema/patologia , Facies , Fibroblastos/metabolismo , Fibroblastos/patologia , Edição de Genes , Técnicas de Inativação de Genes , Transtornos do Crescimento/metabolismo , Transtornos do Crescimento/patologia , Células HEK293 , Humanos , Deficiência Intelectual/metabolismo , Deficiência Intelectual/patologia , Metilação , Metiltransferases/deficiência , Camundongos , Camundongos Knockout , Microcefalia/metabolismo , Microcefalia/patologia , Mitocôndrias/genética , Mitocôndrias/metabolismo , Conformação de Ácido Nucleico , Fosforilação Oxidativa , Cultura Primária de Células , Transporte Proteico , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Mitocondrial/metabolismo , RNA de Transferência/metabolismo
2.
Int J Mol Sci ; 20(12)2019 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-31207912

RESUMO

The 15q11.2 BP1-BP2 microdeletion (Burnside-Butler) syndrome is an emerging disorder that encompasses four genes (NIPA1, NIPA2, CYFIP1, and TUBGCP5). When disturbed, these four genes can lead to cognitive impairment, language and/or motor delay, psychiatric/behavioral problems (attention-deficit hyperactivity, autism, dyslexia, schizophrenia/paranoid psychosis), ataxia, seizures, poor coordination, congenital anomalies, and abnormal brain imaging. This microdeletion was reported as the most common cytogenetic finding when using ultra-high- resolution chromosomal microarrays in patients presenting for genetic services due to autism with or without additional clinical features. Additionally, those individuals with Prader-Willi or Angelman syndromes having the larger typical 15q11-q13 type I deletion which includes the 15q11.2 BP1-BP2 region containing the four genes, show higher clinical severity than those having the smaller 15q11-q13 deletion where these four genes are intact. Two of the four genes (i.e., NIPA1 and NIPA2) are expressed in the brain and encode magnesium transporters. Magnesium is required in over 300 enzyme systems that are critical for multiple cellular functions, energy expenditure, protein synthesis, DNA transcription, and muscle and nerve function. Low levels of magnesium are found in those with seizures, depression, and acute or chronic brain diseases. Anecdotally, parents have administered magnesium supplements to their children with the 15q11.2 BP1-BP2 microdeletion and have observed improvement in behavior and clinical presentation. These observations require more attention from the medical community and should include controlled studies to determine if magnesium supplements could be a treatment option for this microdeletion syndrome and also for a subset of individuals with Prader-Willi and Angelman syndromes.


Assuntos
Deficiência Intelectual/tratamento farmacológico , Magnésio/uso terapêutico , Aberrações Cromossômicas , Cromossomos Humanos Par 15/genética , Cromossomos Humanos Par 15/metabolismo , Suplementos Nutricionais , Humanos , Deficiência Intelectual/genética , Deficiência Intelectual/metabolismo , Magnésio/administração & dosagem
3.
Cell Mol Life Sci ; 76(10): 1935-1945, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30830238

RESUMO

Rab18 is one of the small number of conserved Rab proteins which have been traced to the last eukaryotic common ancestor. It is found in organisms ranging from humans to trypanosomes, and localizes to multiple organelles, including most notably endoplasmic reticulum and lipid droplets. In humans, absence of Rab18 leads to a severe illness known as Warburg-Micro syndrome. Despite this evidence that Rab18 is essential, its role in cells remains mysterious. However, recent studies identifying effectors and interactors of Rab18, are now shedding light on its mechanism of action, suggesting functions related to organelle tethering and to autophagy. In this review, we examine the variety of roles proposed for Rab18 with a focus on new evidence giving insights into the molecular mechanisms it utilizes. Based on this summary of our current understanding, we identify priority areas for further research.


Assuntos
Retículo Endoplasmático/metabolismo , Gotículas Lipídicas/metabolismo , Metabolismo dos Lipídeos , Proteínas rab de Ligação ao GTP/metabolismo , Anormalidades Múltiplas/genética , Anormalidades Múltiplas/metabolismo , Animais , Autofagia/genética , Catarata/congênito , Catarata/genética , Catarata/metabolismo , Córnea/anormalidades , Córnea/metabolismo , Humanos , Hipogonadismo/genética , Hipogonadismo/metabolismo , Deficiência Intelectual/genética , Deficiência Intelectual/metabolismo , Microcefalia/genética , Microcefalia/metabolismo , Modelos Biológicos , Mutação , Atrofia Óptica/genética , Atrofia Óptica/metabolismo , Proteínas rab de Ligação ao GTP/genética
4.
J Hum Genet ; 64(5): 421-426, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30787422

RESUMO

Intellectual disability (ID) is a genetically heterogeneous neurodevelopmental disorder characterised by significantly impaired intellectual and adaptive functioning. ID is commonly syndromic and associated with developmental, metabolic and/or neurological findings. Autosomal recessive ID (ARID) is a significant component of ID especially in the presence of parental consanguinity. Several ultra rare ARID associated variants in numerous genes specific almost to single families have been identified by unbiased next generation sequencing technologies. However, most of these new candidate ARID genes have not been replicated in new families due to the rarity of associated alleles in this highly heterogeneous condition. To determine the genetic component of ARID in a consanguineous family from Turkey, we have performed SNP-based linkage analysis in the family along with whole exome sequencing (WES) in an affected sibling. Eventually, we have identified a novel pathogenic variant in EEF1D, which has recently been recognised as a novel candidate gene for ARID in a single family. EEF1D encodes a ubiquitously expressed translational elongation factor functioning in the cytoplasm. Herein, we suggest that the loss of function variants exclusively targeting the long EEF1D isoform may explicate the ARID phenotype through the heat shock response pathway, rather than interfering with the canonical translational elongation.


Assuntos
Genes Recessivos , Doenças Genéticas Inatas/genética , Deficiência Intelectual/genética , Mutação com Perda de Função , Fator 1 de Elongação de Peptídeos/genética , Polimorfismo de Nucleotídeo Único , Família , Feminino , Doenças Genéticas Inatas/metabolismo , Ligação Genética , Humanos , Deficiência Intelectual/metabolismo , Masculino , Fator 1 de Elongação de Peptídeos/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo
5.
Brain Dev ; 41(6): 538-541, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30795918

RESUMO

PPM1D truncating mutations in the last and penultimate exons of the gene have been associated with intellectual disability (ID) syndrome. Only 15 affected patients to-date have been reported with mild-to-severe ID, autistic behavior, anxiety and dysmorphic features. Here, we describe the clinical characteristics and underlying genetics of two unrelated girls with moderate developmental delay and dysmorphic features associated with novel mutations in PPM1D exon 5. The dysmorphic features demonstrated by these two patients are consistent with previously reported patients, including broad forehead, thin upper lip, brachydactyly, and hypoplastic nails. We identified a de novo PPM1D mutation in exon 5 of each patient (c.1250_1251insACCA p.V419Tfs*16 and c.1256_1257insCAAG p.S421Qfs*14) by panel sequencing for 4,813 disease-related genes. Both patients also had frameshift mutations (at different positions) that resulted in the same estimated termination codon at 434. These additional reports add to the growing literature on PPM1D-associated ID syndrome and help delineate the clinical phenotype and genetic basis.


Assuntos
Deficiência Intelectual/genética , Proteína Fosfatase 2C/genética , Proteína Fosfatase 2C/fisiologia , Criança , Pré-Escolar , Deficiências do Desenvolvimento/genética , Éxons/genética , Feminino , Mutação da Fase de Leitura/genética , Genótipo , Humanos , Deficiência Intelectual/metabolismo , Mutação/genética , Fenótipo , Sequenciamento Completo do Exoma/métodos
6.
Front Horm Res ; 51: 147-159, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30641531

RESUMO

Pseudohypoparathyroidism (PHP), pseudo-PHP, acrodysostosis, and progressive osseous heteroplasia are heterogeneous disorders characterized by physical findings, differently associated in each subtype, including short bones, short stature, a stocky build, ectopic ossifications (features associated with Albright's hereditary osteodystrophy), as well as laboratory abnormalities consistent with hormone resistance, such as hypocalcemia, hyperphosphatemia, and elevated parathyroid hormone (PTH) and thyroid-stimulating hormone levels. All these disorders are caused by impairments in the cAMP-mediated signal transduction pathway and, in particular, in the PTH/PTHrP signaling pathway: the main subtypes of PHP and related disorders are caused by de novo or autosomal dominantly inherited inactivating genetic mutations, and/or epigenetic, sporadic, or genetic-based alterations within or upstream of GNAS, PRKAR1A, PDE4D, and PDE3A. Here we will review the impressive progress that has been made over the past 30 years on the pathophysiology of these diseases and will describe the recently proposed novel nomenclature and classification. The new term "inactivating PTH/PTHrP signaling disorder," iPPSD: (1) defines the common mechanism responsible for all diseases, (2) does not require a confirmed genetic defect, (3) avoids ambiguous terms like "pseudo," and (4) eliminates the clinical or molecular overlap between diseases.


Assuntos
Doenças Ósseas Metabólicas , Disostoses , Deficiência Intelectual , Ossificação Heterotópica , Osteocondrodisplasias , Proteína Relacionada ao Hormônio Paratireóideo/metabolismo , Hormônio Paratireóideo/metabolismo , Pseudo-Hipoparatireoidismo , Transdução de Sinais/fisiologia , Dermatopatias Genéticas , Doenças Ósseas Metabólicas/classificação , Doenças Ósseas Metabólicas/diagnóstico , Doenças Ósseas Metabólicas/metabolismo , Doenças Ósseas Metabólicas/terapia , Disostoses/classificação , Disostoses/diagnóstico , Disostoses/metabolismo , Disostoses/terapia , Humanos , Deficiência Intelectual/classificação , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/metabolismo , Deficiência Intelectual/terapia , Ossificação Heterotópica/classificação , Ossificação Heterotópica/diagnóstico , Ossificação Heterotópica/metabolismo , Ossificação Heterotópica/terapia , Osteocondrodisplasias/classificação , Osteocondrodisplasias/diagnóstico , Osteocondrodisplasias/metabolismo , Osteocondrodisplasias/terapia , Pseudo-Hipoparatireoidismo/classificação , Pseudo-Hipoparatireoidismo/diagnóstico , Pseudo-Hipoparatireoidismo/metabolismo , Pseudo-Hipoparatireoidismo/terapia , Dermatopatias Genéticas/classificação , Dermatopatias Genéticas/diagnóstico , Dermatopatias Genéticas/metabolismo , Dermatopatias Genéticas/terapia
7.
Nat Neurosci ; 22(2): 205-217, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30664766

RESUMO

Nuclear receptor corepressor 1 (NCOR1) and NCOR2 (also known as SMRT) regulate gene expression by activating histone deacetylase 3 through their deacetylase activation domain (DAD). We show that mice with DAD knock-in mutations have memory deficits, reduced anxiety levels, and reduced social interactions. Mice with NCOR1 and NORC2 depletion specifically in GABAergic neurons (NS-V mice) recapitulated the memory deficits and had reduced GABAA receptor subunit α2 (GABRA2) expression in lateral hypothalamus GABAergic (LHGABA) neurons. This was associated with LHGABA neuron hyperexcitability and impaired hippocampal long-term potentiation, through a monosynaptic LHGABA to CA3GABA projection. Optogenetic activation of this projection caused memory deficits, whereas targeted manipulation of LHGABA or CA3GABA neuron activity reversed memory deficits in NS-V mice. We describe de novo variants in NCOR1, NCOR2 or HDAC3 in patients with intellectual disability or neurodevelopmental disorders. These findings identify a hypothalamus-hippocampus projection that may link endocrine signals with synaptic plasticity through NCOR-mediated regulation of GABA signaling.


Assuntos
Região CA3 Hipocampal/metabolismo , Neurônios GABAérgicos/metabolismo , Hipotálamo/metabolismo , Transtornos da Memória/genética , Memória/fisiologia , Correpressor 1 de Receptor Nuclear/genética , Correpressor 2 de Receptor Nuclear/genética , Animais , Bases de Dados Factuais , Potenciais Pós-Sinápticos Excitadores/genética , Deficiência Intelectual/genética , Deficiência Intelectual/metabolismo , Transtornos da Memória/metabolismo , Camundongos , Camundongos Transgênicos , Vias Neurais/metabolismo , Plasticidade Neuronal/fisiologia , Correpressor 1 de Receptor Nuclear/metabolismo , Correpressor 2 de Receptor Nuclear/metabolismo , Receptores de GABA-A/genética , Receptores de GABA-A/metabolismo
8.
Neuroscience ; 399: 199-210, 2019 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-30594563

RESUMO

LIMK2 is involved in neuronal functions by regulating actin dynamics. Different isoforms of LIMK2 are described in databanks. LIMK2a and LIMK2b are the most characterized. A few pieces of evidence suggest that LIMK2 isoforms might not have overlapping functions. In this study, we focused our attention on a less studied human LIMK2 isoform, LIMK2-1. Compared to the other LIMK2 isoforms, LIMK2-1 contains a supplementary C-terminal phosphatase 1 inhibitory domain (PP1i). We found out that this isoform was hominidae-specific and showed that it was expressed in human fetal brain and faintly in adult brain. Its coding sequence was sequenced in 173 patients with sporadic non-syndromic intellectual disability (ID), and we observed an association of a rare missense variant in the PP1i domain (rs151191437, p.S668P) with ID. Our results also suggest an implication of LIMK2-1 in neurite outgrowth and neurons arborization which appears to be affected by the p.S668P variation. Therefore our results suggest that LIMK2-1 plays a role in the developing brain, and that a rare variation of this isoform is a susceptibility factor in ID.


Assuntos
Sistema Nervoso Central/crescimento & desenvolvimento , Sistema Nervoso Central/metabolismo , Deficiência Intelectual/metabolismo , Quinases Lim/metabolismo , Sequência de Aminoácidos , Animais , Células Cultivadas , Sistema Nervoso Central/citologia , Predisposição Genética para Doença , Hominidae , Deficiência Intelectual/genética , Quinases Lim/genética , Camundongos , Modelos Moleculares , Mutação de Sentido Incorreto , Crescimento Neuronal/fisiologia , Neurônios/citologia , Neurônios/metabolismo , Isoformas de Proteínas , Ratos , Homologia de Sequência
9.
Artigo em Inglês | MEDLINE | ID: mdl-30537625

RESUMO

Breath analysis offers a non-invasive and rapid diagnostic method for detecting various volatile organic compounds that could be indicators for different diseases, particularly metabolic disorders including type 2 diabetes mellitus. The development of type 2 diabetes mellitus is closely linked to metabolic dysfunction of adipose tissue and adipocytes. However, the VOC profile of human adipocytes has not yet been investigated. Gas chromatography with mass spectrometric detection and head-space needle trap extraction (two-bed Carbopack X/Carboxen 1000 needle traps) were applied to profile VOCs produced and metabolised by human Simpson Golabi Behmel Syndrome adipocytes. In total, sixteen compounds were identified to be related to the metabolism of the cells. Four sulphur compounds (carbon disulphide, dimethyl sulphide, ethyl methyl sulphide and dimethyl disulphide), three heterocyclic compounds (2-ethylfuran, 2-methyl-5-(methyl-thio)-furan, and 2-pentylfuran), two ketones (acetone and 2-pentanone), two hydrocarbons (isoprene and n-heptane) and one ester (ethyl acetate) were produced, and four aldehydes (2-methyl-propanal, butanal, pentanal and hexanal) were found to be consumed by the cells of interest. This study presents the first profile of VOCs formed by human adipocytes, which may reflect the activity of the adipose tissue enzymes and provide evidence of their active role in metabolic regulation. Our data also suggest that a previously reported increase of isoprene and sulphur compounds in diabetic patients may be explained by their production by adipocytes. Moreover, the unique features of this profile, including a high emission of dimethyl sulphide and the production of furan-containing VOCs, increase our knowledge about metabolism in adipose tissue and provide diagnostic potential for future applications.


Assuntos
Adipócitos/metabolismo , Arritmias Cardíacas/metabolismo , Doenças Genéticas Ligadas ao Cromossomo X/metabolismo , Gigantismo/metabolismo , Cardiopatias Congênitas/metabolismo , Deficiência Intelectual/metabolismo , Compostos Orgânicos Voláteis/análise , Biomarcadores/análise , Biomarcadores/metabolismo , Células Cultivadas , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Compostos Orgânicos Voláteis/metabolismo
11.
Gene ; 679: 305-313, 2018 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-30217758

RESUMO

Histone lysine methylation influences processes such as gene expression and DNA repair. Thirty Jumonji C (JmjC) domain-containing proteins have been identified and phylogenetically clustered into seven subfamilies. Most JmjC domain-containing proteins have been shown to possess histone demethylase activity toward specific histone methylation marks. One of these subfamilies, the KDM5 family, is characterized by five conserved domains and includes four members. Interestingly, de novo loss-of-function and missense variants in KDM5B were identified in patients with intellectual disability (ID) and autism spectrum disorder (ASD) but also in unaffected individuals. Here, we report two novel de novo splice variants in the KDM5B gene in three patients with ID and ASD. The c.808 + 1G > A variant was identified in a boy with mild ID and autism traits and is associated with a significant reduced KDM5B mRNA expression without alteration of its H3K4me3 pattern. In contrast, the c.576 + 2T > C variant was found in twins with global delay in developmental milestones, poor language and ASD. This variant causes the production of an abnormal transcript which may produce an altered protein with the loss of the ARID1B domain with an increase in global gene H3K4me3. Our data reinforces the recent observation that the KDM5B haploinsufficiency is not a mechanism involved in intellectual disability and that KDM5B disorder associated with LOF variants is a recessive disorder. However, some variants may also cause gain of function, and need to be interpreted with caution, and functional studies should be performed to identify the molecular consequences of these different rare variants.


Assuntos
Processamento Alternativo , Transtorno do Espectro Autista/genética , Deficiências do Desenvolvimento/genética , Deficiência Intelectual/genética , Histona Desmetilases com o Domínio Jumonji/genética , Proteínas Nucleares/genética , Proteínas Repressoras/genética , Adolescente , Transtorno do Espectro Autista/metabolismo , Linhagem Celular , Criança , Deficiências do Desenvolvimento/metabolismo , Regulação para Baixo , Feminino , Predisposição Genética para Doença , Haploinsuficiência , Humanos , Deficiência Intelectual/metabolismo , Histona Desmetilases com o Domínio Jumonji/metabolismo , Masculino , Proteínas Nucleares/metabolismo , Linhagem , Proteínas Repressoras/metabolismo
12.
Proc Natl Acad Sci U S A ; 115(28): E6640-E6649, 2018 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-29946028

RESUMO

Endosomes have emerged as a central hub and pathogenic driver of Alzheimer's disease (AD). The earliest brain cytopathology in neurodegeneration, occurring decades before amyloid plaques and cognitive decline, is an expansion in the size and number of endosomal compartments. The strongest genetic risk factor for sporadic AD is the ε4 allele of Apolipoprotein E (ApoE4). Previous studies have shown that ApoE4 potentiates presymptomatic endosomal dysfunction and defective endocytic clearance of amyloid beta (Aß), although how these two pathways are linked at a cellular and mechanistic level has been unclear. Here, we show that aberrant endosomal acidification in ApoE4 astrocytes traps the low-density lipoprotein receptor-related protein (LRP1) within intracellular compartments, leading to loss of surface expression and Aß clearance. Pathological endosome acidification is caused by ε4 risk allele-selective down-regulation of the Na+/H+ exchanger isoform NHE6, which functions as a critical leak pathway for endosomal protons. In vivo, the NHE6 knockout (NHE6KO) mouse model showed elevated Aß in the brain, consistent with a causal effect. Increased nuclear translocation of histone deacetylase 4 (HDAC4) in ApoE4 astrocytes, compared with the nonpathogenic ApoE3 allele, suggested a mechanistic basis for transcriptional down-regulation of NHE6. HDAC inhibitors that restored NHE6 expression normalized ApoE4-specific defects in endosomal pH, LRP1 trafficking, and amyloid clearance. Thus, NHE6 is a downstream effector of ApoE4 and emerges as a promising therapeutic target in AD. These observations have prognostic implications for patients who have Christianson syndrome with loss of function mutations in NHE6 and exhibit prominent glial pathology and progressive hallmarks of neurodegeneration.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Apolipoproteína E4/metabolismo , Astrócitos/metabolismo , Endossomos/metabolismo , Epigênese Genética , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/genética , Animais , Apolipoproteína E4/genética , Astrócitos/patologia , Ataxia/tratamento farmacológico , Ataxia/genética , Ataxia/metabolismo , Ataxia/patologia , Endossomos/genética , Endossomos/patologia , Epilepsia/tratamento farmacológico , Epilepsia/genética , Epilepsia/metabolismo , Epilepsia/patologia , Doenças Genéticas Ligadas ao Cromossomo X/tratamento farmacológico , Doenças Genéticas Ligadas ao Cromossomo X/genética , Doenças Genéticas Ligadas ao Cromossomo X/metabolismo , Doenças Genéticas Ligadas ao Cromossomo X/patologia , Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases/genética , Histona Desacetilases/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Deficiência Intelectual/tratamento farmacológico , Deficiência Intelectual/genética , Deficiência Intelectual/metabolismo , Deficiência Intelectual/patologia , Camundongos , Camundongos Knockout , Microcefalia/tratamento farmacológico , Microcefalia/genética , Microcefalia/metabolismo , Microcefalia/patologia , Transtornos da Motilidade Ocular/tratamento farmacológico , Transtornos da Motilidade Ocular/genética , Transtornos da Motilidade Ocular/metabolismo , Transtornos da Motilidade Ocular/patologia , Receptores de LDL/genética , Receptores de LDL/metabolismo , Trocadores de Sódio-Hidrogênio/genética , Trocadores de Sódio-Hidrogênio/metabolismo , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo
13.
Nat Commun ; 9(1): 1352, 2018 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-29636449

RESUMO

Feingold syndrome is a skeletal dysplasia caused by loss-of-function mutations of either MYCN (type 1) or MIR17HG that encodes miR-17-92 microRNAs (type 2). Since miR-17-92 expression is transcriptionally regulated by MYC transcription factors, it has been postulated that Feingold syndrome type 1 and 2 may be caused by a common molecular mechanism. Here we show that Mir17-92 deficiency upregulates TGF-ß signaling, whereas Mycn-deficiency downregulates PI3K signaling in limb mesenchymal cells. Genetic or pharmacological inhibition of TGF-ß signaling efficiently rescues the skeletal defects caused by Mir17-92 deficiency, suggesting that upregulation of TGF-ß signaling is responsible for the skeletal defect of Feingold syndrome type 2. By contrast, the skeletal phenotype of Mycn-deficiency is partially rescued by Pten heterozygosity, but not by TGF-ß inhibition. These results strongly suggest that despite the phenotypical similarity, distinct molecular mechanisms underlie the pathoetiology for Feingold syndrome type 1 and 2.


Assuntos
Pálpebras/anormalidades , Deficiência Intelectual/genética , Deformidades Congênitas dos Membros/genética , MicroRNAs/genética , Microcefalia/genética , Proteína Proto-Oncogênica N-Myc/genética , Transdução de Sinais/genética , Fístula Traqueoesofágica/genética , Animais , Modelos Animais de Doenças , Pálpebras/metabolismo , Pálpebras/patologia , Feminino , Regulação da Expressão Gênica , Heterozigoto , Humanos , Deficiência Intelectual/metabolismo , Deficiência Intelectual/patologia , Deformidades Congênitas dos Membros/metabolismo , Deformidades Congênitas dos Membros/patologia , Masculino , Camundongos , Camundongos Knockout , MicroRNAs/metabolismo , Microcefalia/metabolismo , Microcefalia/patologia , Proteína Proto-Oncogênica N-Myc/deficiência , PTEN Fosfo-Hidrolase/genética , PTEN Fosfo-Hidrolase/metabolismo , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Fístula Traqueoesofágica/metabolismo , Fístula Traqueoesofágica/patologia , Fator de Crescimento Transformador beta1/genética , Fator de Crescimento Transformador beta1/metabolismo
14.
Am J Case Rep ; 19: 347-353, 2018 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-29574468

RESUMO

BACKGROUND Woodhouse-Sakati syndrome (WSS) is a rare autosomal recessive genetic condition that was first described in 1983. Since its original description, approximately 50 cases have been reported with various clinical signs and symptoms. Characteristics include progressive neurologic deterioration with extrapyramidal involvement and polyendocrinopathy most notable for hypogonadism starting in early adolescence. Clinical presentation is variable, and a subset of patients may have additional features, such as premature aging, alopecia, distinctive facial features, cognitive impairment, or deafness. CASE REPORT We illustrate the phenotypic variability of 5 patients with WSS due to the previously reported homozygous single nucleotide deletion c.436delC in the DCAF17 gene, identified in 2008. Despite identical genetic alteration, our 5 patients had various clinical features among them and compared with previously reported cases with the same pathogenic mutation. CONCLUSIONS The phenotypic variability of WSS due to c.436delC founder mutation may have a wider range than previously recognized.


Assuntos
Alopecia/genética , Arritmias Cardíacas/genética , Doenças dos Gânglios da Base/genética , Encéfalo/patologia , DNA/genética , Diabetes Mellitus/genética , Hipogonadismo/genética , Deficiência Intelectual/genética , Proteínas Nucleares/genética , Complexos Ubiquitina-Proteína Ligase/genética , Adolescente , Adulto , Alopecia/diagnóstico , Alopecia/metabolismo , Arritmias Cardíacas/diagnóstico , Arritmias Cardíacas/metabolismo , Doenças dos Gânglios da Base/diagnóstico , Doenças dos Gânglios da Base/metabolismo , Variação Biológica da População , Análise Mutacional de DNA , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/metabolismo , Feminino , Humanos , Hipogonadismo/diagnóstico , Hipogonadismo/metabolismo , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/metabolismo , Imagem por Ressonância Magnética , Masculino , Proteínas Nucleares/metabolismo , Linhagem , Complexos Ubiquitina-Proteína Ligase/metabolismo , Adulto Jovem
15.
Histochem Cell Biol ; 149(6): 593-605, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29574488

RESUMO

The Simpson-Golabi-Behmel syndrome (SGBS) cell strain is widely considered to be a representative in vitro model of human subcutaneous white pre-adipocytes. These cells achieve a transient expression of classical brown markers, such as uncoupling protein 1, peaking at day 14 of differentiation and decreasing thereafter. Adipocyte browning process involves dynamic changes in lipid droplet (LD) dimension, in mitochondria morphology, and in the expression of brown-specific marker genes. This study analyzes SGBS transient phenotypic transformation by quantifying the heterogeneity of LDs, mitochondrial dynamics, and a panel of genes involved in adipocyte differentiation and browning. LDs at 21 days of differentiation were larger than in the previous stages, without any change in the number per cell. The expression of genes such as peroxisome peroxisome proliferator-activated receptor γ, leptin, and lipase E significantly raised from 0 to 21 days. Adiponectin was significantly upregulated at 14 days of differentiation. Brown-specific marker PR domain containing 16 was highly expressed at D0. The variability of mitochondrial shape and interconnectivity reflects differences in the relative rates of fusion and fission, resulting in a significant shift from a networked shape at D7 to a fragmented and swollen one at D14 and D21. The transient phenotype experienced by this cellular model should be considered whether used in studies involving the stimulation of adipocyte browning and could be an interesting human model to further elucidate the browning process in the absence of any stimulation.


Assuntos
Adipócitos/patologia , Arritmias Cardíacas/patologia , Diferenciação Celular , Doenças Genéticas Ligadas ao Cromossomo X/patologia , Gigantismo/patologia , Cardiopatias Congênitas/patologia , Deficiência Intelectual/patologia , Adipócitos/metabolismo , Arritmias Cardíacas/metabolismo , Células Cultivadas , Doenças Genéticas Ligadas ao Cromossomo X/metabolismo , Gigantismo/metabolismo , Cardiopatias Congênitas/metabolismo , Humanos , Deficiência Intelectual/metabolismo , Gotículas Lipídicas/metabolismo , Gotículas Lipídicas/patologia , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Fenótipo
16.
J Hum Genet ; 63(5): 555-562, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29459631

RESUMO

Kleefstra syndrome (KS) (9q34 deletion syndrome) is a rare autosomal dominant disorder characterized by intellectual disability, frequently coupled with a spectrum of complex physical and clinical manifestations. As the euchromatic histone methyltransferase-1 gene (EHMT1, GLP, or KMT1D) within the 9q34 region is deleted or mutated in most of the individuals with KS, its absence or defect in one allele is speculated to cause the major symptoms of the syndrome. Most of the EHMT1 mutations are frameshift or nonsense mutations, but two individuals with KS were reported to possess EHMT1 missense mutations. These two mutations have been predicted to cause a defective enzymatic function, but precise biochemical validation was not conducted. Therefore, we validated these two mutations by performing in vitro histone methyltransferase (HMT) activity assay and found that C1073Y and R1197W mutations severely affected the HMT activity. Additionally, the same amino-acid substitutions in mouse GLP induced impairment of in vivo GLP function. Furthermore, these two EHMT1 mutants showed defective heterocomplex formation with G9a (partner HMT) which is essential for their in vivo HMT function. Conclusively, our biochemical characterization clearly demonstrates that the previously reported two missense mutations of EHMT1 deteriorate HMT activity and GLP function, which presumably cause KS.


Assuntos
Anormalidades Craniofaciais/genética , Anormalidades Craniofaciais/metabolismo , Cardiopatias Congênitas/genética , Cardiopatias Congênitas/metabolismo , Histona-Lisina N-Metiltransferase/genética , Deficiência Intelectual/genética , Deficiência Intelectual/metabolismo , Mutação de Sentido Incorreto , Substituição de Aminoácidos , Animais , Deleção Cromossômica , Cromossomos Humanos Par 9/genética , Cromossomos Humanos Par 9/metabolismo , Modelos Animais de Doenças , Células-Tronco Embrionárias/metabolismo , Feminino , Antígenos de Histocompatibilidade , Histona-Lisina N-Metiltransferase/química , Histona-Lisina N-Metiltransferase/metabolismo , Histonas/metabolismo , Humanos , Metilação , Camundongos , Camundongos Knockout , Modelos Moleculares , Ligação Proteica , Conformação Proteica , Multimerização Proteica , Relação Estrutura-Atividade
17.
Proc Natl Acad Sci U S A ; 115(11): 2764-2769, 2018 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-29483251

RESUMO

Chemical cues presented on the adhesive substrate direct cell migration, a process termed haptotaxis. To migrate, cells must generate traction forces upon the substrate. However, how cells probe substrate-bound cues and generate directional forces for migration remains unclear. Here, we show that the cell adhesion molecule (CAM) L1-CAM is involved in laminin-induced haptotaxis of axonal growth cones. L1-CAM underwent grip and slip on the substrate. The ratio of the grip state was higher on laminin than on the control substrate polylysine; this was accompanied by an increase in the traction force upon laminin. Our data suggest that the directional force for laminin-induced growth cone haptotaxis is generated by the grip and slip of L1-CAM on the substrates, which occur asymmetrically under the growth cone. This mechanism is distinct from the conventional cell signaling models for directional cell migration. We further show that this mechanism is disrupted in a human patient with L1-CAM syndrome, suffering corpus callosum agenesis and corticospinal tract hypoplasia.


Assuntos
Quimiotaxia , Doenças Genéticas Ligadas ao Cromossomo X/metabolismo , Cones de Crescimento/metabolismo , Deficiência Intelectual/metabolismo , Molécula L1 de Adesão de Célula Nervosa/química , Molécula L1 de Adesão de Célula Nervosa/metabolismo , Paraplegia Espástica Hereditária/metabolismo , Actinas/metabolismo , Axônios/química , Axônios/metabolismo , Movimento Celular , Doenças Genéticas Ligadas ao Cromossomo X/genética , Cones de Crescimento/química , Humanos , Deficiência Intelectual/genética , Laminina/química , Laminina/metabolismo , Molécula L1 de Adesão de Célula Nervosa/genética , Paraplegia Espástica Hereditária/genética
18.
PLoS Genet ; 14(1): e1007165, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29370161

RESUMO

Intellectual disability (ID), one of the most common human developmental disorders, can be caused by genetic mutations in Cullin 4B (Cul4B) and cereblon (CRBN). CRBN is a substrate receptor for the Cul4A/B-DDB1 ubiquitin ligase (CRL4) and can target voltage- and calcium-activated BK channel for ER retention. Here we report that ID-associated CRL4CRBN mutations abolish the interaction of the BK channel with CRL4, and redirect the BK channel to the SCFFbxo7 ubiquitin ligase for proteasomal degradation. Glioma cell lines harbouring CRBN mutations record density-dependent decrease of BK currents, which can be restored by blocking Cullin ubiquitin ligase activity. Importantly, mice with neuron-specific deletion of DDB1 or CRBN express reduced BK protein levels in the brain, and exhibit similar impairment in learning and memory, a deficit that can be partially rescued by activating the BK channel. Our results reveal a competitive targeting of the BK channel by two ubiquitin ligases to achieve exquisite control of its stability, and support changes in neuronal excitability as a common pathogenic mechanism underlying CRL4CRBN-associated ID.


Assuntos
Canais de Potássio Ativados por Cálcio de Condutância Alta/metabolismo , Aprendizagem/fisiologia , Memória/fisiologia , Proteínas do Tecido Nervoso/metabolismo , Proteólise , Proteínas Ligases SKP Culina F-Box/antagonistas & inibidores , Complexos Ubiquitina-Proteína Ligase/metabolismo , Ubiquitina-Proteína Ligases/fisiologia , Animais , Células Cultivadas , Feminino , Células HEK293 , Humanos , Deficiência Intelectual/genética , Deficiência Intelectual/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteínas Ligases SKP Culina F-Box/metabolismo , Complexos Ubiquitina-Proteína Ligase/genética , Ubiquitina-Proteína Ligases/genética , Ubiquitinação
19.
Genome Med ; 10(1): 3, 2018 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-29310717

RESUMO

BACKGROUND: Glycosylphosphatidylinositol biosynthesis defects (GPIBDs) cause a group of phenotypically overlapping recessive syndromes with intellectual disability, for which pathogenic mutations have been described in 16 genes of the corresponding molecular pathway. An elevated serum activity of alkaline phosphatase (AP), a GPI-linked enzyme, has been used to assign GPIBDs to the phenotypic series of hyperphosphatasia with mental retardation syndrome (HPMRS) and to distinguish them from another subset of GPIBDs, termed multiple congenital anomalies hypotonia seizures syndrome (MCAHS). However, the increasing number of individuals with a GPIBD shows that hyperphosphatasia is a variable feature that is not ideal for a clinical classification. METHODS: We studied the discriminatory power of multiple GPI-linked substrates that were assessed by flow cytometry in blood cells and fibroblasts of 39 and 14 individuals with a GPIBD, respectively. On the phenotypic level, we evaluated the frequency of occurrence of clinical symptoms and analyzed the performance of computer-assisted image analysis of the facial gestalt in 91 individuals. RESULTS: We found that certain malformations such as Morbus Hirschsprung and diaphragmatic defects are more likely to be associated with particular gene defects (PIGV, PGAP3, PIGN). However, especially at the severe end of the clinical spectrum of HPMRS, there is a high phenotypic overlap with MCAHS. Elevation of AP has also been documented in some of the individuals with MCAHS, namely those with PIGA mutations. Although the impairment of GPI-linked substrates is supposed to play the key role in the pathophysiology of GPIBDs, we could not observe gene-specific profiles for flow cytometric markers or a correlation between their cell surface levels and the severity of the phenotype. In contrast, it was facial recognition software that achieved the highest accuracy in predicting the disease-causing gene in a GPIBD. CONCLUSIONS: Due to the overlapping clinical spectrum of both HPMRS and MCAHS in the majority of affected individuals, the elevation of AP and the reduced surface levels of GPI-linked markers in both groups, a common classification as GPIBDs is recommended. The effectiveness of computer-assisted gestalt analysis for the correct gene inference in a GPIBD and probably beyond is remarkable and illustrates how the information contained in human faces is pivotal in the delineation of genetic entities.


Assuntos
Citometria de Fluxo/métodos , Glicosilfosfatidilinositóis/biossíntese , Processamento de Imagem Assistida por Computador , Anormalidades Múltiplas/metabolismo , Automação , Biomarcadores/metabolismo , Humanos , Deficiência Intelectual/metabolismo , Fenótipo , Distúrbios do Metabolismo do Fósforo/metabolismo , Síndrome
20.
Am J Med Genet B Neuropsychiatr Genet ; 177(1): 10-20, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28990276

RESUMO

Intellectual Disability (ID) is a clinically heterogeneous condition that affects 2-3% of population worldwide. In recent years, exome sequencing has been a successful strategy for studies of genetic causes of ID, providing a growing list of both candidate and validated ID genes. In this study, exome sequencing was performed on 28 ID patients in 27 patient-parent trios with the aim to identify de novo variants (DNVs) in known and novel ID associated genes. We report the identification of 25 DNVs out of which five were classified as pathogenic or likely pathogenic. Among these, a two base pair deletion was identified in the PUF60 gene, which is one of three genes in the critical region of the 8q24.3 microdeletion syndrome (Verheij syndrome). Our result adds to the growing evidence that PUF60 is responsible for the majority of the symptoms reported for carriers of a microdeletion across this region. We also report variants in several genes previously not associated with ID, including a de novo missense variant in NAA15. We highlight NAA15 as a novel candidate ID gene based on the vital role of NAA15 in the generation and differentiation of neurons in neonatal brain, the fact that the gene is highly intolerant to loss of function and coding variation, and previously reported DNVs in neurodevelopmental disorders.


Assuntos
Deficiência Intelectual/genética , Acetiltransferase N-Terminal A/genética , Acetiltransferase N-Terminal E/genética , Fatores de Processamento de RNA/genética , Proteínas Repressoras/genética , Exoma , Humanos , Deficiência Intelectual/metabolismo , Mutação , Acetiltransferase N-Terminal A/metabolismo , Acetiltransferase N-Terminal E/metabolismo , Transtornos do Neurodesenvolvimento/genética , Fatores de Processamento de RNA/metabolismo , Proteínas Repressoras/metabolismo , Sequenciamento Completo do Exoma/métodos
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