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1.
J Cell Biol ; 218(9): 2826-2828, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31427369

RESUMO

Lamins A and C are intermediate filaments that provide structural support to the nuclear envelope and regulate gene expression. In this issue, Bertero et al. (2019. J. Cell Biol. https://doi.org/10.1083/jcb.201902117) report that although lamin A/C haploinsufficient cardiomyocytes show disease-associated phenotypes, those changes cannot be explained by alterations in chromatin compartmentalization.


Assuntos
Cromatina , Células-Tronco Pluripotentes Induzidas , Haploinsuficiência , Lamina Tipo A/genética , Membrana Nuclear
2.
Nat Commun ; 10(1): 3090, 2019 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-31300647

RESUMO

The role of brain somatic mutations in Alzheimer's disease (AD) is not well understood. Here, we perform deep whole-exome sequencing (average read depth 584×) in 111 postmortem hippocampal formation and matched blood samples from 52 patients with AD and 11 individuals not affected by AD. The number of somatic single nucleotide variations (SNVs) in AD brain specimens increases significantly with aging, and the rate of mutation accumulation in the brain is 4.8-fold slower than that in AD blood. The putatively pathogenic brain somatic mutations identified in 26.9% (14 of 52) of AD individuals are enriched in PI3K-AKT, MAPK, and AMPK pathway genes known to contribute to hyperphosphorylation of tau. We show that a pathogenic brain somatic mutation in PIN1 leads to a loss-of-function mutation. In vitro mimicking of haploinsufficiency of PIN1 aberrantly increases tau phosphorylation and aggregation. This study provides new insights into the genetic architecture underlying the pathogenesis of AD.


Assuntos
Doença de Alzheimer/genética , Peptidilprolil Isomerase de Interação com NIMA/genética , Agregação Patológica de Proteínas/genética , Proteínas tau/metabolismo , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/genética , Doença de Alzheimer/patologia , Animais , Linhagem Celular Tumoral , Feminino , Técnicas de Silenciamento de Genes , Haploinsuficiência , Hipocampo/citologia , Hipocampo/patologia , Humanos , Mutação com Perda de Função , Masculino , Camundongos , Pessoa de Meia-Idade , Taxa de Mutação , Peptidilprolil Isomerase de Interação com NIMA/metabolismo , Neurônios , Fosforilação/genética , Polimorfismo de Nucleotídeo Único , Agregação Patológica de Proteínas/patologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Sequenciamento Completo do Exoma
3.
Biochimie ; 163: 108-116, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31185266

RESUMO

Insulin-like growth factor 1 (IGF1) has a critical role in maintaining tumor phenotype and survival of already transformed murine pheochromocytoma (pheo) cells (MPC4/30) and it is required for the initial establishment of these tumors. However, the role of local IGF1/IGF1R system in tumor microenvironment has not been fully understood. In vivo, by subcutaneous injection of pheo cells in heterozygous IGF1R knockout mice (L/n), we found that the time of noticeable tumor appearance was delayed, and incidence was decreased in L/n group compared to control (L/L) mice. Once established, tumor proliferation, vascularization or growth rate did not differ between groups. In vitro, fibroblast from L/n and L/L mice were cultured to generate conditioned media (CM) and differential matrixes on which pheo cells were seeded. Proliferation rate was higher when pheo cells were cultured with CM, or in differential matrix generated by L/L murine fibroblasts. A diminished fibronectin (FN) expression and secretion from L/n fibroblast was associated with decreased expression of integrin subunits in tumor cells. Also, soluble factors as IGF1 and insulin-like growth factor binding protein 2 (IGFBP2) were reduced. Our data suggest that IGF1 signaling through IGF1R may contribute to tumor cells anchorage and survival by interaction with both matrix and soluble factors produced by tumor microenvironment fibroblasts.


Assuntos
Neoplasias das Glândulas Suprarrenais/fisiopatologia , Proliferação de Células , Fibroblastos/metabolismo , Haploinsuficiência , Feocromocitoma/fisiopatologia , Receptor IGF Tipo 1/genética , Microambiente Tumoral , Neoplasias das Glândulas Suprarrenais/genética , Neoplasias das Glândulas Suprarrenais/metabolismo , Animais , Fibronectinas/genética , Regulação Neoplásica da Expressão Gênica , Masculino , Camundongos , Neovascularização Patológica , Feocromocitoma/genética , Feocromocitoma/metabolismo
4.
Braz J Med Biol Res ; 52(6): e8424, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31141090

RESUMO

Although rare, CALM/AF10 is a chromosomal rearrangement found in immature T-cell acute lymphoblastic leukemia (T-ALL), acute myeloid leukemia, and mixed phenotype acute leukemia of T/myeloid lineages with poor prognosis. Moreover, this translocation is detected in 50% of T-ALL patients with gamma/delta T cell receptor rearrangement, frequently associated with low expression of transcription factor CCAAT/enhancer-binding protein alpha (CEBPA). However, the relevance of CEBPA low expression for CALM/AF10 leukemogenesis has not yet been evaluated. We generated double mutant mice, which express the Lck-CALM/AF10 fusion gene and are haploinsufficient for the Cebpa gene. To characterize the hematopoiesis, we quantified hematopoietic stem cells, myeloid progenitor cells, megakaryocyte-erythrocyte progenitor cells, common myeloid progenitor cells, and granulocyte-macrophage progenitor cells. No significant difference was detected in any of the progenitor subsets. Finally, we tested if Cebpa haploinsufficiency would lead to the expansion of Mac-1+/B220+/c-Kit+ cells proposed as the CALM/AF10 leukemic progenitor. Less than 1% of bone marrow cells expressed Mac-1, B220, and c-Kit with no significant difference between groups. Our results showed that the reduction of Cebpa gene expression in Lck-CALM/AF10 mice did not affect their hematopoiesis or induce leukemia. Our data corroborated previous studies suggesting that the CALM/AF10 leukemia-initiating cells are early progenitors with lymphoid/myeloid differentiating potential.


Assuntos
Proteína alfa Estimuladora de Ligação a CCAAT/genética , Haploinsuficiência/genética , Hematopoese/genética , Leucemia Mieloide Aguda/genética , Doença Aguda , Animais , Citometria de Fluxo , Genótipo , Camundongos , Camundongos Transgênicos , Fenótipo , Fatores de Transcrição/genética , Translocação Genética/genética
5.
Nat Commun ; 10(1): 1917, 2019 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-31015467

RESUMO

STXBP1 and SCN2A gene mutations are observed in patients with epilepsies, although the circuit basis remains elusive. Here, we show that mice with haplodeficiency for these genes exhibit absence seizures with spike-and-wave discharges (SWDs) initiated by reduced cortical excitatory transmission into the striatum. Mice deficient for Stxbp1 or Scn2a in cortico-striatal but not cortico-thalamic neurons reproduce SWDs. In Stxbp1 haplodeficient mice, there is a reduction in excitatory transmission from the neocortex to striatal fast-spiking interneurons (FSIs). FSI activity transiently decreases at SWD onset, and pharmacological potentiation of AMPA receptors in the striatum but not in the thalamus suppresses SWDs. Furthermore, in wild-type mice, pharmacological inhibition of cortico-striatal FSI excitatory transmission triggers absence and convulsive seizures in a dose-dependent manner. These findings suggest that impaired cortico-striatal excitatory transmission is a plausible mechanism that triggers epilepsy in Stxbp1 and Scn2a haplodeficient mice.


Assuntos
Corpo Estriado/metabolismo , Proteínas Munc18/genética , Canal de Sódio Disparado por Voltagem NAV1.2/genética , Neocórtex/metabolismo , Convulsões/genética , Transmissão Sináptica , Potenciais de Ação/efeitos dos fármacos , Animais , Anticonvulsivantes/farmacologia , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/patologia , Dioxóis/farmacologia , Eletroencefalografia , Epilepsia Tipo Ausência/tratamento farmacológico , Epilepsia Tipo Ausência/genética , Epilepsia Tipo Ausência/metabolismo , Epilepsia Tipo Ausência/fisiopatologia , Etossuximida/farmacologia , Regulação da Expressão Gênica , Haploinsuficiência , Interneurônios/efeitos dos fármacos , Interneurônios/metabolismo , Interneurônios/patologia , Camundongos , Camundongos Knockout , Proteínas Munc18/deficiência , Canal de Sódio Disparado por Voltagem NAV1.2/deficiência , Neocórtex/efeitos dos fármacos , Neocórtex/patologia , Vias Neurais/efeitos dos fármacos , Vias Neurais/metabolismo , Piperidinas/farmacologia , Receptores de AMPA/genética , Receptores de AMPA/metabolismo , Convulsões/metabolismo , Convulsões/fisiopatologia , Convulsões/prevenção & controle , Transdução de Sinais , Tálamo/efeitos dos fármacos , Tálamo/metabolismo
6.
Cytogenet Genome Res ; 157(3): 135-140, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30933954

RESUMO

We report a patient with developmental delay, brachydactyly type E, short stature, and tetralogy of Fallot. Brachydactyly-mental retardation syndrome (BDMR) was suspected based on the phenotype; however, array CGH excluded a 2q37 deletion, but identified a deletion encompassing the SHOX gene. BDMR is characterized by cognitive impairment, skeletal abnormalities involving hands and feet, short stature, and overweight. Most affected individuals carry relatively large 2q37 deletions encompassing HDAC4. This gene encodes a histone deacetylase involved in epigenetic regulation of cell growth and differentiation, specifically during endochondral bone formation in chondrocyte hypertrophy. Since SHOX haploinsufficiency can cause skeletal defects and short stature but would not fully explain the clinical picture of this patient, exome sequencing was performed, and a heterozygous HDAC8 frameshift mutation was identified. HDAC8 is a distinct histone deacetylase involved in cohesin recycling and is responsible for an X-linked dominant Cornelia de Lange-like phenotype. A new blended clinical phenotype may be explained by the result of a dual molecular diagnosis, which represents a combination of 2 independent genetic defects, with relevant implications for genetic counseling, clinical management, and prognosis.


Assuntos
Síndrome de Lange/diagnóstico , Mutação da Fase de Leitura , Deleção de Genes , Transtornos do Crescimento/diagnóstico , Histona Desacetilases/genética , Osteocondrodisplasias/diagnóstico , Proteínas Repressoras/genética , Proteína de Homoeobox de Baixa Estatura/genética , Criança , Hibridização Genômica Comparativa , Síndrome de Lange/genética , Feminino , Transtornos do Crescimento/genética , Haploinsuficiência , Humanos , Osteocondrodisplasias/genética , Linhagem , Fenótipo , Sequenciamento Completo do Exoma
7.
Nat Genet ; 51(5): 772-776, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30962618

RESUMO

In numerous applications, from working with animal models to mapping the genetic basis of human disease susceptibility, knowing whether a single disrupting mutation in a gene is likely to be deleterious is useful. With this goal in mind, a number of measures have been developed to identify genes in which protein-truncating variants (PTVs), or other types of mutations, are absent or kept at very low frequency in large population samples-genes that appear 'intolerant' to mutation. One measure in particular, the probability of being loss-of-function intolerant (pLI), has been widely adopted. This measure was designed to classify genes into three categories, null, recessive and haploinsufficient, on the basis of the contrast between observed and expected numbers of PTVs. Such population-genetic approaches can be useful in many applications. As we clarify, however, they reflect the strength of selection acting on heterozygotes and not dominance or haploinsufficiency.


Assuntos
Mutação , Animais , Frequência do Gene , Genes Recessivos , Deriva Genética , Genética Populacional , Haploinsuficiência , Heterozigoto , Humanos , Mutação com Perda de Função , Modelos Genéticos , Seleção Genética
8.
Mol Autism ; 10: 15, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30962870

RESUMO

Background: Mutations of the SCN2A gene encoding a voltage-gated sodium channel alpha-II subunit Nav1.2 are associated with neurological disorders such as epilepsy, autism spectrum disorders, intellectual disability, and schizophrenia. However, causal relationships and pathogenic mechanisms underlying these neurological defects, especially social and psychiatric features, remain to be elucidated. Methods: We investigated the behavior of mice with a conventional or conditional deletion of Scn2a in a comprehensive test battery including open field, elevated plus maze, light-dark box, three chambers, social dominance tube, resident-intruder, ultrasonic vocalization, and fear conditioning tests. We further monitored the effects of the positive allosteric modulator of AMPA receptors CX516 on these model mice. Results: Conventional heterozygous Scn2a knockout mice (Scn2a KO/+) displayed novelty-induced exploratory hyperactivity and increased rearing. The increased vertical activity was reproduced by heterozygous inactivation of Scn2a in dorsal-telencephalic excitatory neurons but not in inhibitory neurons. Moreover, these phenotypes were rescued by treating Scn2a KO/+ mice with CX516. Additionally, Scn2a KO/+ mice displayed mild social behavior impairment, enhanced fear conditioning, and deficient fear extinction. Neuronal activity was intensified in the medial prefrontal cortex of Scn2a KO/+ mice, with an increase in the gamma band. Conclusions: Scn2a KO/+ mice exhibit a spectrum of phenotypes commonly observed in models of schizophrenia and autism spectrum disorder. Treatment with the CX516 ampakine, which ameliorates hyperactivity in these mice, could be a potential therapeutic strategy to rescue some of the disease phenotypes.


Assuntos
Ansiedade/genética , Transtorno do Espectro Autista/genética , Memória , Canal de Sódio Disparado por Voltagem NAV1.2/genética , Agitação Psicomotora/genética , Comportamento Social , Animais , Ansiedade/tratamento farmacológico , Transtorno do Espectro Autista/tratamento farmacológico , Dioxóis/uso terapêutico , Ritmo Gama , Haploinsuficiência , Masculino , Moduladores de Transporte de Membrana/uso terapêutico , Camundongos , Camundongos Endogâmicos C57BL , Fenótipo , Piperidinas/uso terapêutico , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/fisiopatologia , Agitação Psicomotora/tratamento farmacológico
9.
Nat Neurosci ; 22(4): 556-564, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30911184

RESUMO

Heterozygous loss-of-function mutations in SHANK2 are associated with autism spectrum disorder (ASD). We generated cortical neurons from induced pluripotent stem cells derived from neurotypic and ASD-affected donors. We developed sparse coculture for connectivity assays where SHANK2 and control neurons were differentially labeled and sparsely seeded together on a lawn of unlabeled control neurons. We observed increases in dendrite length, dendrite complexity, synapse number, and frequency of spontaneous excitatory postsynaptic currents. These findings were phenocopied in gene-edited homozygous SHANK2 knockout cells and rescued by gene correction of an ASD SHANK2 mutation. Dendrite length increases were exacerbated by IGF1, TG003, or BDNF, and suppressed by DHPG treatment. The transcriptome in isogenic SHANK2 neurons was perturbed in synapse, plasticity, and neuronal morphogenesis gene sets and ASD gene modules, and activity-dependent dendrite extension was impaired. Our findings provide evidence for hyperconnectivity and altered transcriptome in SHANK2 neurons derived from ASD subjects.


Assuntos
Transtorno do Espectro Autista/genética , Transtorno do Espectro Autista/patologia , Dendritos/patologia , Proteínas do Tecido Nervoso/genética , Neurônios/patologia , Transtorno do Espectro Autista/metabolismo , Técnicas de Cocultura , Dendritos/metabolismo , Potenciais Pós-Sinápticos Excitadores , Técnicas de Inativação de Genes , Haploinsuficiência , Humanos , Células-Tronco Pluripotentes Induzidas , Masculino , Plasticidade Neuronal , Neurônios/metabolismo , Transcriptoma
10.
Adv Genet ; 103: 163-182, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30904094

RESUMO

Mutations in CDK13 have recently been identified as a novel cause of syndromic intellectual disability. In this chapter, we review the 44 cases of CDK13-related disorder reported to date, highlighting key clinical pointers to this diagnosis including characteristic craniofacial features, feeding difficulties in infancy, and the presence of structural heart or brain malformations. The spectrum of reported mutations is also described, demonstrating an excess of missense mutations arising in the protein kinase domain. Exploration of genotype-phenotype correlations suggests a trend toward milder phenotypes in patients with mutations predicted to cause haploinsufficiency of CDK13, while missense mutations affecting amino acid residue 842 appear most likely to be associated with structural malformations. The greater phenotypic impact of missense variants is hypothesized to occur due to a dominant-negative mechanism, by which the mutant protein acts to sequester cyclin K in inactive complexes. Functional studies to validate this hypothesis have not yet been carried out, however. Differential diagnosis and recommendations for clinical care of patients with CDK13-related disorder are also described, emphasizing baseline echocardiography, vigilance for feeding and swallowing difficulties, and regular developmental evaluation as key components of care. Finally, future directions for CDK13 research are discussed, including the need to resolve uncertainty regarding pathogenicity of CDK13 haploinsufficiency, and to gather further longitudinal data from large cohorts in order to inform the clinical care of patients with this diagnosis.


Assuntos
Proteína Quinase CDC2/genética , Deficiência Intelectual/genética , Mutação de Sentido Incorreto , Encéfalo/patologia , Diagnóstico Diferencial , Feminino , Genótipo , Haploinsuficiência , Humanos , Deficiência Intelectual/diagnóstico , Masculino , Fenótipo
11.
Nat Commun ; 10(1): 1252, 2019 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-30890702

RESUMO

Clonal hematopoiesis driven by somatic heterozygous TET2 loss is linked to malignant degeneration via consequent aberrant DNA methylation, and possibly to cardiovascular disease via increased cytokine and chemokine expression as reported in mice. Here, we discover a germline TET2 mutation in a lymphoma family. We observe neither unusual predisposition to atherosclerosis nor abnormal pro-inflammatory cytokine or chemokine expression. The latter finding is confirmed in cells from three additional unrelated TET2 germline mutation carriers. The TET2 defect elevates blood DNA methylation levels, especially at active enhancers and cell-type specific regulatory regions with binding sequences of master transcription factors involved in hematopoiesis. The regions display reduced methylation relative to all open chromatin regions in four DNMT3A germline mutation carriers, potentially due to TET2-mediated oxidation. Our findings provide insight into the interplay between epigenetic modulators and transcription factor activity in hematological neoplasia, but do not confirm the putative role of TET2 in atherosclerosis.


Assuntos
Aterosclerose/genética , Metilação de DNA/genética , Proteínas de Ligação a DNA/genética , Haploinsuficiência , Doença de Hodgkin/genética , Proteínas Proto-Oncogênicas/genética , Adulto , Aterosclerose/patologia , Células Cultivadas , DNA (Citosina-5-)-Metiltransferases/genética , DNA (Citosina-5-)-Metiltransferases/metabolismo , Proteínas de Ligação a DNA/metabolismo , Epigênese Genética , Feminino , Finlândia , Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Hematopoese/genética , Doença de Hodgkin/sangue , Doença de Hodgkin/patologia , Humanos , Masculino , Fenótipo , Cultura Primária de Células , Proteínas Proto-Oncogênicas/metabolismo , RNA Interferente Pequeno/metabolismo , Sequenciamento Completo do Genoma
12.
Mol Cell ; 73(6): 1089-1091, 2019 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-30901561

RESUMO

In this issue of Molecular Cell, Zong et al. (2019) reveal RNF168-driven chromatin ubiquitylation as a key back-up mechanism to sustain homologous recombination (HR) independently of BRCA1. These findings provide new clues to carcinogenesis and cancer therapy in BRCA1 heterozygous mutation carriers.


Assuntos
Cromatina , Haploinsuficiência , Proteína BRCA1/genética , Linhagem Celular Tumoral , Recombinação Homóloga , Ubiquitinação
13.
Taiwan J Obstet Gynecol ; 58(2): 292-295, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30910156

RESUMO

OBJECTIVES: To present the prenatal findings and the molecular cytogenetic analyses of a de novo interstitial deletion of 1q23.3 encompassing PBX1 gene. CASE REPORT: A 32-year-old woman (gravida 1, para 0) underwent amniocentesis at 26 weeks' gestation because of constant small fetal kidneys on prenatal ultrasound. Chromosome microarray analysis (CMA) detected a de novo deletion of 1.871 Mb at 1q23.3. The deletion encompassed 2 genes of PBX1 and LMX1A. PBX1 haploinsufficiency had been reported to lead syndromic congenital anomalies of kidney and urinary tract (CAKUT) in humans. Furthermore, at 31 weeks' gestation, borderline oligohydramnios and restricted fetal dimensions were revealed. Ultimately, the pregnancy was terminated at 32 weeks with a 1500-g female fetus presenting polydactyl of left hand. CONCLUSIONS: The shared phenotypes between this case and the previously published prenatal cases demonstrate that loss of function mutation in PBX1 should be suspicious in fetus with bilateral renal hypoplasia, oligohydramnios and intrauterine growth retardation (IUGR).


Assuntos
Deleção Cromossômica , Haploinsuficiência/genética , Fator de Transcrição 1 de Leucemia de Células Pré-B/genética , Aborto Eugênico , Adulto , Amniocentese , Análise Citogenética , Feminino , Humanos , Rim/diagnóstico por imagem , Rim/embriologia , Gravidez , Sindactilia/genética , Ultrassonografia Pré-Natal
14.
Genome Med ; 11(1): 18, 2019 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-30914057

RESUMO

As trials of immune checkpoint inhibitor (ICI) therapies demonstrate responses in only a minority of pleural mesotheliomas (PlMs) and largely exclude patients with the related peritoneal mesothelioma (PeM), clinicians need predictive biomarkers of response and inclusion of PeM patients in future trials. A new study finds that loss of the deubiquitinase BAP1 in PeM correlates with an inflammatory tumor microenvironment, suggesting that BAP1 status might identify PeM, and possibly PlM, patients who would benefit from ICI therapy.


Assuntos
Neoplasias Pulmonares , Mesotelioma , Biomarcadores Tumorais , Haploinsuficiência , Humanos , Imunoterapia , Proteínas Supressoras de Tumor/genética , Ubiquitina Tiolesterase/genética
15.
Nature ; 566(7743): 275-278, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30700905

RESUMO

Genetic instability, a heritable increase in the rate of genetic mutation, accelerates evolutionary adaptation1 and is widespread in cancer2,3. In mammals, instability can arise from damage to both copies of genes involved in DNA metabolism and cell cycle regulation4 or from inactivation of one copy of a gene whose product is present in limiting amounts (haploinsufficiency5); however, it has proved difficult to determine the relative importance of these two mechanisms. In Escherichia coli6, the application of repeated, strong selection enriches for genetic instability. Here we have used this approach to evolve genetic instability in diploid cells of the budding yeast Saccharomyces cerevisiae, and have isolated clones with increased rates of point mutation, mitotic recombination, and chromosome loss. We identified candidate, heterozygous, instability-causing mutations; engineering these mutations, as heterozygotes, into the ancestral diploid strain caused genetic instability. Mutations that inactivated one copy of haploinsufficient genes were more common than those that dominantly altered the function of the mutated gene copy. The mutated genes were enriched for genes functioning in transport, protein quality control, and DNA metabolism, and have revealed new targets for genetic instability7-11, including essential genes. Although only a minority (10 out of 57 genes with orthologues or close homologues) of the targets we identified have homologous human genes that have been implicated in cancer2, the remainder are candidates to contribute to human genetic instability. To test this hypothesis, we inactivated six examples in a near-haploid human cell line; five of these mutations increased instability. We conclude that single genetic events cause genetic instability in diploid yeast cells, and propose that similar, heterozygous mutations in mammalian homologues initiate genetic instability in cancer.


Assuntos
Evolução Molecular , Instabilidade Genômica/genética , Heterozigoto , Modelos Genéticos , Mutação , Neoplasias/genética , Saccharomyces cerevisiae/genética , Linhagem Celular , Diploide , Haploinsuficiência/genética , Humanos , Mutagênese/genética , Taxa de Mutação , Mutação Puntual
16.
Blood ; 133(12): 1358-1370, 2019 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-30700418

RESUMO

Diamond-Blackfan anemia (DBA) is a congenital erythroblastopenia that is characterized by a blockade in erythroid differentiation related to impaired ribosome biogenesis. DBA phenotype and genotype are highly heterogeneous. We have previously identified 2 in vitro erythroid cell growth phenotypes for primary CD34+ cells from DBA patients and following short hairpin RNA knockdown of RPS19, RPL5, and RPL11 expression in normal human CD34+ cells. The haploinsufficient RPS19 in vitro phenotype is less severe than that of 2 other ribosomal protein (RP) mutant genes. We further documented that proteasomal degradation of HSP70, the chaperone of GATA1, is a major contributor to the defect in erythroid proliferation, delayed erythroid differentiation, increased apoptosis, and decreased globin expression, which are all features of the RPL5 or RPL11 DBA phenotype. In the present study, we explored the hypothesis that an imbalance between globin and heme synthesis may be involved in pure red cell aplasia of DBA. We identified disequilibrium between the globin chain and the heme synthesis in erythroid cells of DBA patients. This imbalance led to accumulation of excess free heme and increased reactive oxygen species production that was more pronounced in cells of the RPL5 or RPL11 phenotype. Strikingly, rescue experiments with wild-type HSP70 restored GATA1 expression levels, increased globin synthesis thereby reducing free heme excess and resulting in decreased apoptosis of DBA erythroid cells. These results demonstrate the involvement of heme in DBA pathophysiology and a major role of HSP70 in the control of balanced heme/globin synthesis.


Assuntos
Anemia de Diamond-Blackfan/patologia , Diferenciação Celular , Células Eritroides/patologia , Fator de Transcrição GATA1/metabolismo , Globinas/metabolismo , Proteínas de Choque Térmico HSP70/metabolismo , Heme/metabolismo , Anemia de Diamond-Blackfan/metabolismo , Proliferação de Células , Células Cultivadas , Células Eritroides/metabolismo , Feminino , Seguimentos , Haploinsuficiência , Humanos , Lactente , Recém-Nascido , Masculino , Mutação , Fenótipo , Prognóstico , RNA Interferente Pequeno , Proteínas Ribossômicas/genética , Proteínas Ribossômicas/metabolismo
17.
PLoS One ; 14(2): e0211647, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30716086

RESUMO

Classical Ehlers-Danlos syndrome (cEDS) is a dominant inherited connective tissue disorder mainly caused by mutations in the COL5A1 and COL5A2 genes encoding type V collagen (COLLV), which is a fibrillar COLL widely distributed in a variety of connective tissues. cEDS patients suffer from skin hyperextensibility, abnormal wound healing/atrophic scars, and joint hypermobility. Most of the causative variants result in a non-functional COL5A1 allele and COLLV haploinsufficiency, whilst COL5A2 mutations affect its structural integrity. To shed light into disease mechanisms involved in cEDS, we performed gene expression profiling in skin fibroblasts from four patients harboring haploinsufficient and structural mutations in both disease genes. Transcriptome profiling revealed significant changes in the expression levels of different extracellular matrix (ECM)-related genes, such as SPP1, POSTN, EDIL3, IGFBP2, and C3, which encode both matricellular and soluble proteins that are mainly involved in cell proliferation and migration, and cutaneous wound healing. These gene expression changes are consistent with our previous protein findings on in vitro fibroblasts from other cEDS patients, which exhibited reduced migration and poor wound repair owing to COLLV disorganization, altered deposition of fibronectin into ECM, and an abnormal integrin pattern. Microarray analysis also indicated the decreased expression of DNAJB7, VIPAS39, CCPG1, ATG10, SVIP, which encode molecular chaperones facilitating protein folding, enzymes regulating post-Golgi COLLs processing, and proteins acting as cargo receptors required for endoplasmic reticulum (ER) proteostasis and implicated in the autophagy process. Patients' cells also showed altered mRNA levels of many cell cycle regulating genes including CCNE2, KIF4A, MKI67, DTL, and DDIAS. Protein studies showed that aberrant COLLV expression causes the disassembly of itself and many structural ECM constituents including COLLI, COLLIII, fibronectin, and fibrillins. Our findings provide the first molecular evidence of significant gene expression changes in cEDS skin fibroblasts highlighting that defective ECM remodeling, ER homeostasis and autophagy might play a role in the pathogenesis of this connective tissue disorder.


Assuntos
Síndrome de Ehlers-Danlos/genética , Síndrome de Ehlers-Danlos/patologia , Fibroblastos/fisiologia , Anormalidades da Pele/genética , Anormalidades da Pele/patologia , Pele/patologia , Transcriptoma/genética , Adulto , Alelos , Estudos de Casos e Controles , Ciclo Celular/genética , Células Cultivadas , Colágeno/genética , Tecido Conjuntivo/fisiologia , Retículo Endoplasmático/genética , Matriz Extracelular/genética , Feminino , Fibronectinas/genética , Perfilação da Expressão Gênica/métodos , Haploinsuficiência/genética , Humanos , Masculino , Pessoa de Meia-Idade , Mutação/genética , RNA Mensageiro/genética
18.
Genome Med ; 11(1): 8, 2019 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-30777124

RESUMO

BACKGROUND: Malignant peritoneal mesothelioma (PeM) is a rare and fatal cancer that originates from the peritoneal lining of the abdomen. Standard treatment of PeM is limited to cytoreductive surgery and/or chemotherapy, and no effective targeted therapies for PeM exist. Some immune checkpoint inhibitor studies of mesothelioma have found positivity to be associated with a worse prognosis. METHODS: To search for novel therapeutic targets for PeM, we performed a comprehensive integrative multi-omics analysis of the genome, transcriptome, and proteome of 19 treatment-naïve PeM, and in particular, we examined BAP1 mutation and copy number status and its relationship to immune checkpoint inhibitor activation. RESULTS: We found that PeM could be divided into tumors with an inflammatory tumor microenvironment and those without and that this distinction correlated with haploinsufficiency of BAP1. To further investigate the role of BAP1, we used our recently developed cancer driver gene prioritization algorithm, HIT'nDRIVE, and observed that PeM with BAP1 haploinsufficiency form a distinct molecular subtype characterized by distinct gene expression patterns of chromatin remodeling, DNA repair pathways, and immune checkpoint receptor activation. We demonstrate that this subtype is correlated with an inflammatory tumor microenvironment and thus is a candidate for immune checkpoint blockade therapies. CONCLUSIONS: Our findings reveal BAP1 to be a potential, easily trackable prognostic and predictive biomarker for PeM immunotherapy that refines PeM disease classification. BAP1 stratification may improve drug response rates in ongoing phases I and II clinical trials exploring the use of immune checkpoint blockade therapies in PeM in which BAP1 status is not considered. This integrated molecular characterization provides a comprehensive foundation for improved management of a subset of PeM patients.


Assuntos
Biomarcadores Tumorais/genética , Haploinsuficiência , Mesotelioma/genética , Neoplasias Peritoneais/genética , Proteínas Supressoras de Tumor/genética , Ubiquitina Tiolesterase/genética , Biomarcadores Tumorais/metabolismo , Humanos , Imunoterapia , Mesotelioma/classificação , Mesotelioma/terapia , Mutação , Neoplasias Peritoneais/classificação , Neoplasias Peritoneais/terapia , Microambiente Tumoral , Proteínas Supressoras de Tumor/metabolismo , Ubiquitina Tiolesterase/metabolismo
19.
Mol Autism ; 10: 5, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30792833

RESUMO

Background: Autism spectrum disorders (ASD) exhibit two clusters of core symptoms, i.e., social and communication impairment, and repetitive behaviors and sensory abnormalities. Our previous study demonstrated that TBR1, a causative gene of ASD, controls axonal projection and neuronal activation of amygdala and regulates social interaction and vocal communication in a mouse model. Behavioral defects caused by Tbr1 haploinsufficiency can be ameliorated by increasing neural activity via D-cycloserine treatment, an N-methyl-D-aspartate receptor (NMDAR) coagonist. In this report, we investigate the role of TBR1 in regulating olfaction and test whether D-cycloserine can also improve olfactory defects in Tbr1 mutant mice. Methods: We used Tbr1 +/- mice as a model to investigate the function of TBR1 in olfactory sensation and discrimination of non-social odors. We employed a behavioral assay to characterize the olfactory defects of Tbr1 +/- mice. Magnetic resonance imaging (MRI) and histological analysis were applied to characterize anatomical features. Immunostaining was performed to further analyze differences in expression of TBR1 subfamily members (namely TBR1, TBR2, and TBX21), interneuron populations, and dendritic abnormalities in olfactory bulbs. Finally, C-FOS staining was used to monitor neuronal activation of the olfactory system upon odor stimulation. Results: Tbr1 +/- mice exhibited smaller olfactory bulbs and anterior commissures, reduced interneuron populations, and an abnormal dendritic morphology of mitral cells in the olfactory bulbs. Tbr1 haploinsufficiency specifically impaired olfactory discrimination but not olfactory sensation. Neuronal activation upon odorant stimulation was reduced in the glomerular layer of Tbr1 +/- olfactory bulbs. Furthermore, although the sizes of piriform and perirhinal cortices were not affected by Tbr1 deficiency, neuronal activation was reduced in these two cortical regions in response to odorant stimulation. These results suggest an impairment of neuronal activation in olfactory bulbs and defective connectivity from olfactory bulbs to the upper olfactory system in Tbr1 +/- mice. Systemic administration of D-cycloserine, an NMDAR co-agonist, ameliorated olfactory discrimination in Tbr1 +/- mice, suggesting that increased neuronal activity has a beneficial effect on Tbr1 deficiency. Conclusions: Tbr1 regulates neural circuits and activity in the olfactory system to control olfaction. Tbr1 +/- mice can serve as a suitable model for revealing how an autism causative gene controls neuronal circuits, neural activity, and autism-related behaviors.


Assuntos
Transtorno do Espectro Autista/genética , Proteínas de Ligação a DNA/genética , Discriminação (Psicologia) , Haploinsuficiência , Percepção Olfatória , Animais , Ciclosserina/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/metabolismo , Neurônios/patologia , Bulbo Olfatório/efeitos dos fármacos , Bulbo Olfatório/patologia , Bulbo Olfatório/fisiologia , Receptores de N-Metil-D-Aspartato/agonistas , Olfato
20.
Gene ; 696: 33-39, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30763665

RESUMO

Hereditary hemorrhagic telangiectasia (HHT) is a vascular rare disease characterized by nose and gastrointestinal bleeding, skin and mucosa telangiectasias, and arteriovenous malformations in internal organs. HHT shows an autosomal dominant inheritance and a worldwide prevalence of approximately 1:5000 individuals. In >80% of patients, HHT is caused by mutations in either ENG (HHT1) or ACVRL1 (HHT2) genes, which code for the membrane proteins Endoglin and Activin A Receptor Type II-Like Kinase 1 (ALK1), respectively, both belonging to the TGF-ß/BMP signaling pathway. In this work, we describe a novel mutation in exon 9 of ENG (c.1145 G > A) found in five affected members of a family, all of them with characteristic symptoms of HHT. This mutation involves Cys382 residue of the Endoglin protein (p.Cys382 > Tyr) in the zona pellucida (ZP) module of its extracellular region. This is a critical residue involved in a conserved intrachain disulphide bond and in the correct folding of the protein. In fact, transfection studies in human cells using Endoglin expression vectors demonstrated that the p.Cys382 > Tyr mutation results in a marked reduction in the levels of the Endoglin protein. These results demonstrate the pathogenic role for this variant in HHT1 and confirm the key function of Cys382 in Endoglin expression.


Assuntos
Endoglina/genética , Domínios Proteicos/genética , Telangiectasia Hemorrágica Hereditária/genética , Adulto , Criança , Cisteína/genética , Endoglina/metabolismo , Éxons/genética , Feminino , Haploinsuficiência/genética , Humanos , Itália , Masculino , Pessoa de Meia-Idade , Linhagem , Dobramento de Proteína , Transdução de Sinais , Telangiectasia Hemorrágica Hereditária/patologia , Adulto Jovem
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