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1.
Am J Hum Genet ; 107(4): 753-762, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32910914

RESUMO

Lamin B1 plays an important role in the nuclear envelope stability, the regulation of gene expression, and neural development. Duplication of LMNB1, or missense mutations increasing LMNB1 expression, are associated with autosomal-dominant leukodystrophy. On the basis of its role in neurogenesis, it has been postulated that LMNB1 variants could cause microcephaly. Here, we confirm this hypothesis with the identification of de novo mutations in LMNB1 in seven individuals with pronounced primary microcephaly (ranging from -3.6 to -12 SD) associated with relative short stature and variable degree of intellectual disability and neurological features as the core symptoms. Simplified gyral pattern of the cortex and abnormal corpus callosum were noted on MRI of three individuals, and these individuals also presented with a more severe phenotype. Functional analysis of the three missense mutations showed impaired formation of the LMNB1 nuclear lamina. The two variants located within the head group of LMNB1 result in a decrease in the nuclear localization of the protein and an increase in misshapen nuclei. We further demonstrate that another mutation, located in the coil region, leads to increased frequency of condensed nuclei and lower steady-state levels of lamin B1 in proband lymphoblasts. Our findings collectively indicate that de novo mutations in LMNB1 result in a dominant and damaging effect on nuclear envelope formation that correlates with microcephaly in humans. This adds LMNB1 to the growing list of genes implicated in severe autosomal-dominant microcephaly and broadens the phenotypic spectrum of the laminopathies.


Assuntos
Nanismo/genética , Deficiência Intelectual/genética , Lamina Tipo B/genética , Microcefalia/genética , Mutação , Lâmina Nuclear/genética , Sequência de Aminoácidos , Sequência de Bases , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Pré-Escolar , Corpo Caloso/diagnóstico por imagem , Corpo Caloso/metabolismo , Corpo Caloso/patologia , Nanismo/diagnóstico por imagem , Nanismo/metabolismo , Nanismo/patologia , Feminino , Expressão Gênica , Humanos , Lactente , Deficiência Intelectual/diagnóstico por imagem , Deficiência Intelectual/metabolismo , Deficiência Intelectual/patologia , Lamina Tipo B/metabolismo , Linfócitos/metabolismo , Linfócitos/patologia , Imagem por Ressonância Magnética , Masculino , Microcefalia/diagnóstico por imagem , Microcefalia/metabolismo , Microcefalia/patologia , Lâmina Nuclear/metabolismo , Lâmina Nuclear/patologia
2.
J Neurosci ; 40(28): 5376-5388, 2020 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-32503885

RESUMO

Missense variants in Kirrel3 are repeatedly identified as risk factors for autism spectrum disorder and intellectual disability, but it has not been reported if or how these variants disrupt Kirrel3 function. Previously, we studied Kirrel3 loss of function using KO mice and showed that Kirrel3 is a synaptic adhesion molecule necessary to form one specific type of hippocampal synapse in vivo Here, we developed an in vitro, gain-of-function assay for Kirrel3 using neuron cultures prepared from male and female mice and rats. We find that WT Kirrel3 induces synapse formation selectively between Kirrel3-expressing neurons via homophilic, transcellular binding. We tested six disease-associated Kirrel3 missense variants and found that five attenuate this synaptogenic function. All variants tested traffic to the cell surface and localize to synapses similar to WT Kirrel3. Two tested variants lack homophilic transcellular binding, which likely accounts for their reduced synaptogenic function. Interestingly, we also identified variants that bind in trans but cannot induce synapses, indicating that Kirrel3 transcellular binding is necessary but not sufficient for its synaptogenic function. Collectively, these results suggest Kirrel3 functions as a synaptogenic, cell-recognition molecule, and this function is attenuated by missense variants associated with autism spectrum disorder and intellectual disability. Thus, we provide critical insight to the mechanism of Kirrel3 function and the consequences of missense variants associated with autism and intellectual disability.SIGNIFICANCE STATEMENT Here, we advance our understanding of mechanisms mediating target-specific synapse formation by providing evidence that Kirrel3 transcellular interactions mediate target recognition and signaling to promote synapse development. Moreover, this study tests the effects of disease-associated Kirrel3 missense variants on synapse formation, and thereby, increases understanding of the complex etiology of neurodevelopmental disorders arising from rare missense variants in synaptic genes.


Assuntos
Hipocampo/metabolismo , Proteínas de Membrana/genética , Mutação de Sentido Incorreto , Neurônios/metabolismo , Sinapses/metabolismo , Animais , Transtorno Autístico/genética , Transtorno Autístico/metabolismo , Adesão Celular/fisiologia , Células Cultivadas , Feminino , Hipocampo/citologia , Deficiência Intelectual/genética , Deficiência Intelectual/metabolismo , Masculino , Proteínas de Membrana/metabolismo , Camundongos , Ratos
3.
Hum Genet ; 139(10): 1247-1259, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32306098

RESUMO

Congenital diarrheal disorders (CDD) comprise > 50 monogenic entities featuring chronic diarrhea of early-onset, including defects in nutrient and electrolyte absorption, enterocyte polarization, enteroendocrine cell differentiation, and epithelial integrity. Diarrhea is also a predominant symptom in many immunodeficiencies, congenital disorders of glycosylation, and in some defects of the vesicular sorting and transporting machinery. We set out to identify the etiology of an intractable diarrhea in 2 consanguineous families by whole-exome sequencing, and identified two novel AP1S1 mutations, c.269T>C (p.Leu90Pro) and c.346G>A (p.Glu116Lys). AP1S1 encodes the small subunit of the adaptor protein 1 complex (AP-1), which plays roles in clathrin coat-assembly and trafficking between trans-Golgi network, endosomes and the plasma membrane. An AP1S1 knock-out (KO) of a CaCo2 intestinal cell line was generated to characterize intestinal AP1S1 deficiency as well as identified mutations by stable expression in KO background. Morphology and prototype transporter protein distribution were comparable between parental and KO cells. We observed altered localization of tight-junction proteins ZO-1 and claudin 3, decreased transepithelial electrical resistance and an increased dextran permeability of the CaCo2-AP1S1-KO monolayer. In addition, lumen formation in 3D cultures of these cells was abnormal. Re-expression of wild-type AP1S1 in CaCo2-AP1S1-KO cells reverted these abnormalities, while expression of AP1S1 containing either missense mutation did not. Our data indicate that loss of AP1S1 function causes an intestinal epithelial barrier defect, and that AP1S1 mutations can cause a non-syndromic form of congenital diarrhea, whereas 2 reported truncating AP1S1 mutations caused MEDNIK syndrome, characterized by mental retardation, enteropathy, deafness, neuropathy, ichthyosis, and keratodermia.


Assuntos
Complexo 1 de Proteínas Adaptadoras/genética , Subunidades sigma do Complexo de Proteínas Adaptadoras/genética , Surdez/genética , Diarreia/genética , Ictiose/genética , Deficiência Intelectual/genética , Ceratodermia Palmar e Plantar/genética , Mutação de Sentido Incorreto , Complexo 1 de Proteínas Adaptadoras/deficiência , Subunidades sigma do Complexo de Proteínas Adaptadoras/deficiência , Sequência de Bases , Células CACO-2 , Claudina-3/genética , Claudina-3/metabolismo , Consanguinidade , Surdez/diagnóstico , Surdez/metabolismo , Surdez/patologia , Diarreia/diagnóstico , Diarreia/metabolismo , Diarreia/patologia , Feminino , Expressão Gênica , Técnicas de Inativação de Genes , Teste de Complementação Genética , Humanos , Ictiose/diagnóstico , Ictiose/metabolismo , Ictiose/patologia , Lactente , Recém-Nascido , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/metabolismo , Deficiência Intelectual/patologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Ceratodermia Palmar e Plantar/diagnóstico , Ceratodermia Palmar e Plantar/metabolismo , Ceratodermia Palmar e Plantar/patologia , Linhagem , Permeabilidade , Sequenciamento Completo do Exoma , Proteína da Zônula de Oclusão-1/genética , Proteína da Zônula de Oclusão-1/metabolismo
4.
Nat Commun ; 11(1): 480, 2020 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-31980599

RESUMO

Mutations in the actively expressed, maternal allele of the imprinted KCNK9 gene cause Birk-Barel intellectual disability syndrome (BBIDS). Using a BBIDS mouse model, we identify here a partial rescue of the BBIDS-like behavioral and neuronal phenotypes mediated via residual expression from the paternal Kcnk9 (Kcnk9pat) allele. We further demonstrate that the second-generation HDAC inhibitor CI-994 induces enhanced expression from the paternally silenced Kcnk9 allele and leads to a full rescue of the behavioral phenotype suggesting CI-994 as a promising molecule for BBIDS therapy. Thus, these findings suggest a potential approach to improve cognitive dysfunction in a mouse model of an imprinting disorder.


Assuntos
Anormalidades Craniofaciais/genética , Anormalidades Craniofaciais/metabolismo , Histonas/metabolismo , Deficiência Intelectual/genética , Deficiência Intelectual/metabolismo , Hipotonia Muscular/genética , Hipotonia Muscular/metabolismo , Canais de Potássio/genética , Animais , Comportamento Animal , Encéfalo/metabolismo , Anormalidades Craniofaciais/tratamento farmacológico , Modelos Animais de Doenças , Feminino , Técnicas de Silenciamento de Genes , Impressão Genômica , Inibidores de Histona Desacetilases/farmacologia , Humanos , Deficiência Intelectual/tratamento farmacológico , Locus Cerúleo/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Hipotonia Muscular/tratamento farmacológico , Mutação , Fenótipo , Fenilenodiaminas/farmacologia , Canais de Potássio/deficiência , Canais de Potássio/metabolismo , Regulação para Cima/efeitos dos fármacos
5.
FEBS Lett ; 594(4): 717-727, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31627256

RESUMO

X-linked intellectual disabilities (XLID) are common developmental disorders. The enzyme O-GlcNAc transferase encoded by OGT, a recently discovered XLID gene, attaches O-GlcNAc to nuclear and cytoplasmic proteins. As few missense mutations have been described, it is unclear what the aetiology of the patient phenotypes is. Here, we report the discovery of a missense mutation in the catalytic domain of OGT in an XLID patient. X-ray crystallography reveals that this variant leads to structural rearrangements in the catalytic domain. The mutation reduces in vitro OGT activity on substrate peptides/protein. Mouse embryonic stem cells carrying the mutation reveal reduced O-GlcNAcase (OGA) and global O-GlcNAc levels. These data suggest a direct link between changes in the O-GlcNAcome and intellectual disability observed in patients carrying OGT mutations.


Assuntos
Domínio Catalítico , Deficiência Intelectual/enzimologia , Deficiência Intelectual/genética , Mutação de Sentido Incorreto , N-Acetilglucosaminiltransferases/química , N-Acetilglucosaminiltransferases/genética , Animais , Linhagem Celular , Glicosilação , Humanos , Deficiência Intelectual/metabolismo , Camundongos , Modelos Moleculares , N-Acetilglucosaminiltransferases/metabolismo
6.
Brain Dev ; 42(2): 192-198, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31706665

RESUMO

BACKGROUND: Coffin-Siris syndrome (CSS) is a neurodevelopmental disorder characterized by somatic dysmorphic features, developmental and speech delay. It is due to mutations in many different genes, belonging to BAF chromatin-remodelling complex. The last gene involved in this complex, recently individuated and related to CSS, was DPF2, although only nine patients have been reported until now. METHOD: Here we report on a boy with a history of developmental delay, especially regarding speech and language, and dysmorphic features resembling a syndromic condition. Array-Comparative Genomic Hybridization (CGH) and a custom Next Generation Sequencing (NGS) panel including developmental delay related genes were executed. RESULTS: Array-CGH was negative while NGS panel revealed a novel mutation in DPF2 gene. CONCLUSIONS: We add the clinical description of another patient with a novel mutation in DPF2, with a mild phenotype, thus trying to contribute to enlarge CSS phenotypic variability. Moreover, we briefly discuss about cohesinopathies and major differential diagnosis among syndromes with phenotypes overlapping to CSS.


Assuntos
Síndrome de Coffin-Lowry/genética , Proteínas de Ligação a DNA/genética , Mutação de Sentido Incorreto , Fatores de Transcrição/genética , Criança , Síndrome de Coffin-Lowry/diagnóstico , Síndrome de Coffin-Lowry/metabolismo , Hibridização Genômica Comparativa/métodos , Proteínas de Ligação a DNA/metabolismo , Deficiências do Desenvolvimento/diagnóstico , Deficiências do Desenvolvimento/genética , Deficiências do Desenvolvimento/metabolismo , Diagnóstico Diferencial , Epigênese Genética , Humanos , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/genética , Deficiência Intelectual/metabolismo , Masculino , Mutação/genética , Fenótipo , Fatores de Transcrição/metabolismo
7.
Clin Chim Acta ; 500: 128-134, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31654632

RESUMO

Myhre syndrome is a rare autosomal dominant multi-organ disorder characterized by growth retardation, skeletal anomalies, muscular hypertrophy, joint stiffness, facial dysmorphism, deafness, cardiovascular disease, and abnormal sexual development. Here we described the first two Chinese Myhre syndrome patients diagnosed by whole-exome sequencing. They both had de novo c.1498A > G (p.Ile500Val) variant in SMAD4 and presented with key characteristics of Myhre syndrome but also revealed uncommon features (polydactyly in the girl and precocious puberty in the boy). We performed functional analysis on four previously reported SMAD4 pathogenic variants in Myhre syndrome patients using dual-luciferase assay. Our results revealed that the pathogenic variants resulted in a variable degree of increased transcription activity of target genes that contain the minimal SMAD binding elements in their promoter regions. The boy responded to the recombinant human growth hormone treatment with improved height but also led to hyperinsulinemia and advanced bone age. Because of his precocious puberty, we subsequently combined the recombinant human growth hormone and gonadotrophin-releasing hormone agonist treatments, which resulted in overall improved height. We reviewed the sexual features of reported Myhre syndrome cases and discussed the possible mechanism of SMAD4 variants in Myhre syndrome that lead to the abnormal hypothalamic-pituitary-gonadal axis.


Assuntos
Criptorquidismo/genética , Criptorquidismo/metabolismo , Variação Genética , Transtornos do Crescimento/genética , Transtornos do Crescimento/metabolismo , Deformidades Congênitas da Mão/genética , Deformidades Congênitas da Mão/metabolismo , Deficiência Intelectual/genética , Deficiência Intelectual/metabolismo , Proteína Smad4/genética , Proteína Smad4/metabolismo , Sequência de Bases , Pré-Escolar , China , Criptorquidismo/patologia , Facies , Feminino , Transtornos do Crescimento/patologia , Deformidades Congênitas da Mão/patologia , Humanos , Lactente , Deficiência Intelectual/patologia , Masculino , Gravidez
8.
Clin Dysmorphol ; 29(1): 46-48, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31205051
9.
Cell Rep ; 29(8): 2422-2437.e8, 2019 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-31747610

RESUMO

Palmitoylation is a reversible post-translational lipid modification that facilitates vesicular transport and subcellular localization of modified proteins. This process is catalyzed by ZDHHC enzymes that are implicated in several neurological and neurodevelopmental disorders. Loss-of-function mutations in ZDHHC9 have been identified in patients with X-linked intellectual disability (XLID) and associated with increased epilepsy risk. Loss of Zdhhc9 function in hippocampal cultures leads to shorter dendritic arbors and fewer inhibitory synapses, altering the ratio of excitatory-to-inhibitory inputs formed onto Zdhhc9-deficient cells. While Zdhhc9 promotes dendrite outgrowth through the palmitoylation of the GTPase Ras, it promotes inhibitory synapse formation through the palmitoylation of another GTPase, TC10. Zdhhc9 knockout mice exhibit seizure-like activity together with increased frequency and amplitude of both spontaneous and miniature excitatory and inhibitory postsynaptic currents. These findings present a plausible mechanism for how the loss of ZDHHC9 function may contribute to XLID and epilepsy.


Assuntos
Aciltransferases/metabolismo , Dendritos/metabolismo , Genes Ligados ao Cromossomo X/fisiologia , Deficiência Intelectual/metabolismo , Sinapses/metabolismo , Aciltransferases/genética , Animais , Células Cultivadas , Epilepsia/genética , Epilepsia/metabolismo , Genes Ligados ao Cromossomo X/genética , Hipocampo/metabolismo , Humanos , Deficiência Intelectual/genética , Lipoilação/genética , Lipoilação/fisiologia , Camundongos , Camundongos Knockout , Sinapses/genética , Proteínas ras/metabolismo , Proteínas rho de Ligação ao GTP/genética , Proteínas rho de Ligação ao GTP/metabolismo
10.
Nat Commun ; 10(1): 4928, 2019 10 30.
Artigo em Inglês | MEDLINE | ID: mdl-31666522

RESUMO

Kleefstra syndrome (KS) is a neurodevelopmental disorder caused by mutations in the histone methyltransferase EHMT1. To study the impact of decreased EHMT1 function in human cells, we generated excitatory cortical neurons from induced pluripotent stem (iPS) cells derived from KS patients. Neuronal networks of patient-derived cells exhibit network bursting with a reduced rate, longer duration, and increased temporal irregularity compared to control networks. We show that these changes are mediated by upregulation of NMDA receptor (NMDAR) subunit 1 correlating with reduced deposition of the repressive H3K9me2 mark, the catalytic product of EHMT1, at the GRIN1 promoter. In mice EHMT1 deficiency leads to similar neuronal network impairments with increased NMDAR function. Finally, we rescue the KS patient-derived neuronal network phenotypes by pharmacological inhibition of NMDARs. Summarized, we demonstrate a direct link between EHMT1 deficiency and NMDAR hyperfunction in human neurons, providing a potential basis for more targeted therapeutic approaches for KS.


Assuntos
Anormalidades Craniofaciais/genética , Cardiopatias Congênitas/genética , Histona-Lisina N-Metiltransferase/genética , Deficiência Intelectual/genética , Proteínas do Tecido Nervoso/genética , Neurônios/metabolismo , Receptores de N-Metil-D-Aspartato/genética , Animais , Córtex Cerebral/citologia , Deleção Cromossômica , Cromossomos Humanos Par 9/genética , Cromossomos Humanos Par 9/metabolismo , Anormalidades Craniofaciais/metabolismo , Modelos Animais de Doenças , Maleato de Dizocilpina/farmacologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Feminino , Cardiopatias Congênitas/metabolismo , Histona-Lisina N-Metiltransferase/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas , Deficiência Intelectual/metabolismo , Mutação com Perda de Função , Masculino , Camundongos , Proteínas do Tecido Nervoso/antagonistas & inibidores , Proteínas do Tecido Nervoso/metabolismo , Neurônios/efeitos dos fármacos , Cultura Primária de Células , Receptores de AMPA/metabolismo , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Receptores de N-Metil-D-Aspartato/metabolismo , Regulação para Cima
11.
Nat Commun ; 10(1): 4457, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31575858

RESUMO

Mutations in genes encoding KATP channel subunits have been reported for pancreatic disorders and Cantú syndrome. Here, we report a syndrome in six patients from two families with a consistent phenotype of mild intellectual disability, similar facies, myopathy, and cerebral white matter hyperintensities, with cardiac systolic dysfunction present in the two oldest patients. Patients are homozygous for a splice-site mutation in ABCC9 (c.1320 + 1 G > A), which encodes the sulfonylurea receptor 2 (SUR2) subunit of KATP channels. This mutation results in an in-frame deletion of exon 8, which results in non-functional KATP channels in recombinant assays. SUR2 loss-of-function causes fatigability and cardiac dysfunction in mice, and reduced activity, cardiac dysfunction and ventricular enlargement in zebrafish. We term this channelopathy resulting from loss-of-function of SUR2-containing KATP channels ABCC9-related Intellectual disability Myopathy Syndrome (AIMS). The phenotype differs from Cantú syndrome, which is caused by gain-of-function ABCC9 mutations, reflecting the opposing consequences of KATP loss- versus gain-of-function.


Assuntos
Trifosfato de Adenosina/metabolismo , Canalopatias/metabolismo , Predisposição Genética para Doença/genética , Deficiência Intelectual/metabolismo , Doenças Musculares/metabolismo , Mutação , Receptores Sulfonilureia/genética , Receptores Sulfonilureia/metabolismo , Adolescente , Adulto , Sequência de Aminoácidos , Animais , Cardiomegalia/genética , Cardiomegalia/metabolismo , Linhagem Celular , Criança , Modelos Animais de Doenças , Facies , Feminino , Doenças Genéticas Ligadas ao Cromossomo X/genética , Coração , Cardiopatias/genética , Cardiopatias/metabolismo , Homozigoto , Humanos , Hipertricose/genética , Hipertricose/metabolismo , Deficiência Intelectual/parasitologia , Masculino , Complexo Mediador/metabolismo , Proteínas de Membrana/metabolismo , Camundongos , Doenças Musculares/genética , Transtornos do Neurodesenvolvimento/genética , Transtornos do Neurodesenvolvimento/metabolismo , Transtornos do Neurodesenvolvimento/fisiopatologia , Osteocondrodisplasias/genética , Osteocondrodisplasias/metabolismo , Linhagem , Fenótipo , Rubídio , Sequenciamento Completo do Genoma , Adulto Jovem , Peixe-Zebra
12.
Stem Cell Res ; 40: 101556, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31518906

RESUMO

The 3p26.3 microduplication involving the CNTN6 gene cause developmental delay and the intellectual disability. However, the incomplete penetrance is described for this copy number variation (CNV). Here we describe ICAGi002-A line, which is supposed to use as a model for studying of the penetrance of the CNV in 3p26.3. The ICAGi002-A iPSCs line was obtained by the reprogramming of the skin fibroblasts from a healthy donor with 3p26.3 microduplication involving the CNTN6 gene. The ICAGi002-A cells was pluripotent as it was shown by the expression of the pluripotency-associated markers and in vitro differentiation into the cells of three germ layers.


Assuntos
Linhagem Celular/citologia , Contactinas/genética , Células-Tronco Pluripotentes Induzidas/citologia , Deficiência Intelectual/genética , Adulto , Diferenciação Celular , Linhagem Celular/metabolismo , Reprogramação Celular , Contactinas/metabolismo , Variações do Número de Cópias de DNA , Fibroblastos/citologia , Fibroblastos/metabolismo , Duplicação Gênica , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Deficiência Intelectual/metabolismo , Deficiência Intelectual/fisiopatologia , Masculino
13.
Cells ; 8(9)2019 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-31514269

RESUMO

Rho family small guanosine triphosphatases (GTPases) are important regulators of the cytoskeleton, and are critical in many aspects of cellular and developmental biology, as well as in pathological processes such as intellectual disability and cancer. Of the three members of the family, Rac3 has a more restricted expression in normal tissues compared to the ubiquitous member of the family, Rac1. The Rac3 polypeptide is highly similar to Rac1, and orthologues of the gene for Rac3 have been found only in vertebrates, indicating the late appearance of this gene during evolution. Increasing evidence over the past few years indicates that Rac3 plays an important role in neuronal development and in tumor progression, with specificities that distinguish the functions of Rac3 from the established functions of Rac1 in these processes. Here, results highlighting the importance of Rac3 in distinct aspects of neuronal development and tumor cell biology are presented, in support of the non-redundant role of different members of the two Rac GTPases in physiological and pathological processes.


Assuntos
Proteínas rac de Ligação ao GTP/metabolismo , Animais , Humanos , Deficiência Intelectual/enzimologia , Deficiência Intelectual/metabolismo , Neoplasias/enzimologia , Neoplasias/metabolismo , Transtornos do Neurodesenvolvimento/metabolismo , Neurogênese/fisiologia , Neurônios/enzimologia , Neurônios/metabolismo , Proteínas rac1 de Ligação ao GTP/metabolismo
14.
Genesis ; 57(11-12): e23336, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31520578

RESUMO

Acrodysostosis is an extremely rare disorder at birth, that is, characterized by skeletal dysplasia with short stature and midfacial hypoplasia, which has been reported to be caused by PDE4D and PRKAR1A gene mutations. Here, a Chinese boy with acrodysostosis, ventricular septal defect, and pulmonary hypertension was recruited for our study, and his clinical and biochemical characteristics were analyzed. A novel de novo heterozygous missense mutation (NM_001104631: c.2030A>C, p.Tyr677Ser) of the PDE4D gene was detected by whole exome sequencing and confirmed by Sanger sequencing. The c.2030A>C (p.Tyr677Ser) variant was located in exon 15 of the PDE4D gene, predicted to be damaging by a functional prediction program and shown to be highly conserved among many species. Further functional analysis showed that the p.Tyr677Ser substitution changes the function of the PDE4D protein, affects its subcellular localization in transfected cells, increases PDE4 activity in the regulation of cAMP signaling and affects cell proliferation. Our study identified a novel de novo PDE4D mutation in acrodysostosis of Chinese origin that not only contributes a deeper appreciation of the phenotypic characteristics of patients with PDE4D mutations but also expands the spectrum of PDE4D mutations.


Assuntos
Nucleotídeo Cíclico Fosfodiesterase do Tipo 4/genética , Disostoses/genética , Deficiência Intelectual/genética , Osteocondrodisplasias/genética , Grupo com Ancestrais do Continente Asiático/genética , Pré-Escolar , China , Nucleotídeo Cíclico Fosfodiesterase do Tipo 4/metabolismo , Disostoses/metabolismo , Células HEK293 , Células HeLa , Heterozigoto , Humanos , Deficiência Intelectual/metabolismo , Masculino , Mutação , Mutação de Sentido Incorreto/genética , Osteocondrodisplasias/metabolismo , Sequenciamento Completo do Exoma
15.
Artigo em Inglês | MEDLINE | ID: mdl-31444167

RESUMO

Intellectual disability (ID) is a clinically and genetically heterogeneous developmental brain disorder. The present study describes two male siblings, aged 7 and 1 yr old, with severe ID, spastic quadriplegia, nystagmus, and brain atrophy with acquired microcephaly. We used the exome sequencing to identify the causative gene in the patients and identified a hemizygous missense variant, c.1282T>A (p.W428R), in the p21-activated serine/threonine kinase 3 gene (PAK3), which is associated with X-linked ID. p.W428R is located within the highly conserved kinase domain and was predicted to induce loss of enzymatic function by three mutation prediction tools (SIFT, PolyPhen-2, and MutationTaster). In addition, this variant has not been reported in public databases (as of the middle of December 2018) or in the data from 3275 individuals of the Japanese general population analyzed using high-depth whole-genome sequencing. To date, only 13 point mutations and deletions in PAK3 in ID have been reported. The literature review illustrated a phenotypic spectrum of PAK3 pathogenic variant, and our cases represented the most severe form of the PAK3-associated phenotypes. This is the first report of a PAK3 pathogenic variant in Japanese patients with X-linked ID.


Assuntos
Retardo Mental Ligado ao Cromossomo X/genética , Quinases Ativadas por p21/genética , Criança , Deficiências do Desenvolvimento/genética , Exoma , Genes Ligados ao Cromossomo X/genética , Estudos de Associação Genética , Humanos , Lactente , Deficiência Intelectual/genética , Deficiência Intelectual/metabolismo , Japão , Masculino , Retardo Mental Ligado ao Cromossomo X/metabolismo , Microcefalia/genética , Mutação , Mutação de Sentido Incorreto/genética , Linhagem , Fenótipo , Irmãos , Sequenciamento Completo do Exoma/métodos , Quinases Ativadas por p21/metabolismo
16.
Mol Cell ; 75(5): 891-904.e7, 2019 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-31375262

RESUMO

Mammalian SWI/SNF complexes are multi-subunit chromatin remodeling complexes associated with an ATPase (either SMARCA4 or SMARCA2). Heterozygous mutations in the SMARCA2 ATPase cause Nicolaides-Baraitser syndrome (NCBRS), an intellectual disability syndrome associated with delayed speech onset. We engineered human embryonic stem cells (hESCs) to carry NCBRS-associated heterozygous SMARCA2 K755R or R1159Q mutations. While SMARCA2 mutant hESCs were phenotypically normal, differentiation to neural progenitors cells (NPCs) was severely impaired. We find that SMARCA2 mutations cause enhancer reorganization with loss of SOX3-dependent neural enhancers and prominent emergence of astrocyte-specific de novo enhancers. Changes in chromatin accessibility at enhancers were associated with an increase in SMARCA2 binding and retargeting of SMARCA4. We show that the AP-1 family member FRA2 is aberrantly overexpressed in SMARCA2 mutant NPCs, where it functions as a pioneer factor at de novo enhancers. Together, our results demonstrate that SMARCA2 mutations cause impaired differentiation through enhancer reprogramming via inappropriate targeting of SMARCA4.


Assuntos
DNA Helicases/metabolismo , Elementos Facilitadores Genéticos , Heterozigoto , Células-Tronco Embrionárias Humanas/metabolismo , Mutação de Sentido Incorreto , Proteínas Nucleares/metabolismo , Fatores de Transcrição/metabolismo , Substituição de Aminoácidos , Diferenciação Celular/genética , Cromatina/genética , Cromatina/metabolismo , DNA Helicases/genética , Facies , Deformidades Congênitas do Pé/genética , Deformidades Congênitas do Pé/metabolismo , Deformidades Congênitas do Pé/patologia , Antígeno 2 Relacionado a Fos/biossíntese , Antígeno 2 Relacionado a Fos/genética , Células HEK293 , Células-Tronco Embrionárias Humanas/patologia , Humanos , Hipotricose/genética , Hipotricose/metabolismo , Hipotricose/patologia , Deficiência Intelectual/genética , Deficiência Intelectual/metabolismo , Deficiência Intelectual/patologia , Células-Tronco Neurais/metabolismo , Células-Tronco Neurais/patologia , Proteínas Nucleares/genética , Fatores de Transcrição SOXB1/genética , Fatores de Transcrição SOXB1/metabolismo , Fatores de Transcrição/genética
17.
Stem Cell Res ; 39: 101518, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31376723

RESUMO

Mowat-Wilson syndrome (MWS) is a complex developmental syndrome caused by heterozygous mutations in the Zinc finger E-box-binding homeobox 2 gene (ZEB2). We generated the first human iPSC lines from primary fibroblasts of two siblings with MWS carrying a heterozygous ZEB2 stop mutation (c.1027C > T; p.Arg343*) using the Sendai virus reprogramming system. Both iPSC lines were free from reprogramming vector genes, expressed pluripotency markers and showed potential to differentiate into the three germ layers. Genetic analysis confirmed normal karyotypes and a preserved stop mutation. These iPSC lines will provide a useful resource to study altered neural lineage fate and neuropathophysiology in MWS.


Assuntos
Doença de Hirschsprung/metabolismo , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Deficiência Intelectual/metabolismo , Microcefalia/metabolismo , Homeobox 2 de Ligação a E-box com Dedos de Zinco/genética , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , Linhagem Celular , Criança , Facies , Feminino , Humanos , Masculino , Mutação/genética
18.
EMBO Mol Med ; 11(7): e10201, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31273937

RESUMO

PARN, poly(A)-specific ribonuclease, regulates the turnover of mRNAs and the maturation and stabilization of the hTR RNA component of telomerase. Biallelic PARN mutations were associated with Høyeraal-Hreidarsson (HH) syndrome, a rare telomere biology disorder that, because of its severity, is likely not exclusively due to hTR down-regulation. Whether PARN deficiency was affecting the expression of telomere-related genes was still unclear. Using cells from two unrelated HH individuals carrying novel PARN mutations and a human PARN knock-out (KO) cell line with inducible PARN complementation, we found that PARN deficiency affects both telomere length and stability and down-regulates the expression of TRF1, TRF2, TPP1, RAP1, and POT1 shelterin transcripts. Down-regulation of dyskerin-encoding DKC1 mRNA was also observed and found to result from p53 activation in PARN-deficient cells. We further showed that PARN deficiency compromises ribosomal RNA biogenesis in patients' fibroblasts and cells from heterozygous Parn KO mice. Homozygous Parn KO however resulted in early embryonic lethality that was not overcome by p53 KO. Our results refine our knowledge on the pleiotropic cellular consequences of PARN deficiency.


Assuntos
Disceratose Congênita/metabolismo , Exorribonucleases/deficiência , Retardo do Crescimento Fetal/metabolismo , Deficiência Intelectual/metabolismo , Microcefalia/metabolismo , RNA Ribossômico/biossíntese , Homeostase do Telômero , Telômero/metabolismo , Animais , Pré-Escolar , Modelos Animais de Doenças , Disceratose Congênita/genética , Disceratose Congênita/patologia , Exorribonucleases/metabolismo , Feminino , Retardo do Crescimento Fetal/genética , Retardo do Crescimento Fetal/patologia , Humanos , Deficiência Intelectual/genética , Deficiência Intelectual/patologia , Masculino , Camundongos , Camundongos Knockout , Microcefalia/genética , Microcefalia/patologia , RNA Ribossômico/genética , Telômero/genética , Telômero/patologia
19.
Trends Biochem Sci ; 44(9): 733-736, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31279651

RESUMO

Heterogeneous nuclear ribonucleoprotein K (hnRNPK) is an RNA-binding protein that regulates multiple biological processes, including paraspeckles formation and cellular signal transduction. Recently, hnRNPK has been shown to interact with SINE-derived nuclear RNA localization (SIRLOIN)-containing RNAs, and orchestrate nuclear enrichment and cellular functions of long noncoding RNAs (lncRNAs). hnRNPK-lncRNAs interaction is potentially implicated in various pathogenic disorders including tumorigenesis, and Kabuki-like, Au-Kline, and Okamoto syndromes.


Assuntos
Fissura Palatina/metabolismo , Ribonucleoproteínas Nucleares Heterogêneas Grupo K/metabolismo , Hidronefrose/metabolismo , Deficiência Intelectual/metabolismo , Hipotonia Muscular/metabolismo , Síndromes Paraneoplásicas/metabolismo , RNA Longo não Codificante/metabolismo , Anormalidades Múltiplas/metabolismo , Face/anormalidades , Facies , Doenças Hematológicas/metabolismo , Humanos , Doenças Vestibulares/metabolismo
20.
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
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