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1.
Mol Biol Rep ; 45(5): 1001-1011, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30030774

RESUMO

HIRA is a histone chaperone known to modulate gene expression through the deposition of H3.3. Conditional knockout of Hira in embryonic mouse hearts leads to cardiac septal defects. Loss of function mutation in HIRA, together with other chromatin modifiers, was found in patients with congenital heart diseases. However, the effects of HIRA on gene expression at earlier stages of cardiogenic mesoderm differentiation have not yet been studied. Differentiation of mouse embryonic stem cells (mESCs) towards cardiomyocytes mimics some of these early events and is an accepted model of these early stages. We performed RNA-Seq and H3.3-HA ChIP-seq on both WT and Hira-null mESCs and early cardiomyocyte progenitors of both genotypes. Analysis of RNA-seq data showed differential down regulation of cardiovascular development-related genes in Hira-null cardiomyocytes compared to WT cardiomyocytes. We found HIRA-dependent H3.3 deposition at these genes. In particular, we observed that HIRA influenced directly the expression of the transcription factors Gata6, Meis1 and Tbx2, essential for cardiac septation, through H3.3 deposition. We therefore identified new direct targets of HIRA during cardiac differentiation.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Chaperonas de Histonas/metabolismo , Células-Tronco Embrionárias Murinas/citologia , Miócitos Cardíacos/citologia , Análise de Sequência de RNA/métodos , Fatores de Transcrição/genética , Animais , Diferenciação Celular , Linhagem Celular , Regulação para Baixo , Elementos Facilitadores Genéticos , Fator de Transcrição GATA6/genética , Defeitos dos Septos Cardíacos/embriologia , Defeitos dos Septos Cardíacos/metabolismo , Histonas/metabolismo , Mutação com Perda de Função , Camundongos , Células-Tronco Embrionárias Murinas/metabolismo , Proteína Meis1/genética , Miócitos Cardíacos/metabolismo , Proteínas com Domínio T/genética , Fatores de Transcrição/metabolismo
2.
PLoS One ; 11(8): e0161096, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27518902

RESUMO

Chromatin remodelling is essential for cardiac development. Interestingly, the role of histone chaperones has not been investigated in this regard. HIRA is a member of the HUCA (HIRA/UBN1/CABIN1/ASF1a) complex that deposits the variant histone H3.3 on chromatin independently of replication. Lack of HIRA has general effects on chromatin and gene expression dynamics in embryonic stem cells and mouse oocytes. Here we describe the conditional ablation of Hira in the cardiogenic mesoderm of mice. We observed surface oedema, ventricular and atrial septal defects and embryonic lethality. We identified dysregulation of a subset of cardiac genes, notably upregulation of troponins Tnni2 and Tnnt3, involved in cardiac contractility and decreased expression of Epha3, a gene necessary for the fusion of the muscular ventricular septum and the atrioventricular cushions. We found that HIRA binds GAGA rich DNA loci in the embryonic heart, and in particular a previously described enhancer of Tnni2/Tnnt3 (TTe) bound by the transcription factor NKX2.5. HIRA-dependent H3.3 enrichment was observed at the TTe in embryonic stem cells (ESC) differentiated toward cardiomyocytes in vitro. Thus, we show here that HIRA has locus-specific effects on gene expression and that histone chaperone activity is vital for normal heart development, impinging on pathways regulated by an established cardiac transcription factor.


Assuntos
Proteínas de Ciclo Celular/fisiologia , Regulação da Expressão Gênica , Coração/embriologia , Chaperonas de Histonas/fisiologia , Miócitos Cardíacos/citologia , Fatores de Transcrição/fisiologia , Troponina I/metabolismo , Troponina/metabolismo , Animais , Diferenciação Celular , Linhagem da Célula , Células Cultivadas , Embrião de Mamíferos/citologia , Embrião de Mamíferos/metabolismo , Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/metabolismo , Proteína Homeobox Nkx-2.5/genética , Proteína Homeobox Nkx-2.5/metabolismo , Camundongos , Camundongos Knockout , Miócitos Cardíacos/metabolismo , Troponina/genética , Troponina I/genética
3.
J Med Genet ; 52(3): 147-56, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25564561

RESUMO

BACKGROUND: Mutations in microtubule-regulating genes are associated with disorders of neuronal migration and microcephaly. Regulation of centriole length has been shown to underlie the pathogenesis of certain ciliopathy phenotypes. Using a next-generation sequencing approach, we identified mutations in a novel centriolar disease gene in a kindred with an embryonic lethal ciliopathy phenotype and in a patient with primary microcephaly. METHODS AND RESULTS: Whole exome sequencing data from a non-consanguineous Caucasian kindred exhibiting mid-gestation lethality and ciliopathic malformations revealed two novel non-synonymous variants in CENPF, a microtubule-regulating gene. All four affected fetuses showed segregation for two mutated alleles [IVS5-2A>C, predicted to abolish the consensus splice-acceptor site from exon 6; c.1744G>T, p.E582X]. In a second unrelated patient exhibiting microcephaly, we identified two CENPF mutations [c.1744G>T, p.E582X; c.8692 C>T, p.R2898X] by whole exome sequencing. We found that CENP-F colocalised with Ninein at the subdistal appendages of the mother centriole in mouse inner medullary collecting duct cells. Intraflagellar transport protein-88 (IFT-88) colocalised with CENP-F along the ciliary axonemes of renal epithelial cells in age-matched control human fetuses but did not in truncated cilia of mutant CENPF kidneys. Pairwise co-immunoprecipitation assays of mitotic and serum-starved HEKT293 cells confirmed that IFT88 precipitates with endogenous CENP-F. CONCLUSIONS: Our data identify CENPF as a new centriolar disease gene implicated in severe human ciliopathy and microcephaly related phenotypes. CENP-F has a novel putative function in ciliogenesis and cortical neurogenesis.


Assuntos
Proteínas Cromossômicas não Histona/genética , Cílios/genética , Genética Médica , Microcefalia/genética , Proteínas dos Microfilamentos/genética , Animais , Centríolos/genética , Cílios/patologia , Exoma/genética , Feminino , Feto , Células HEK293 , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Camundongos , Microcefalia/patologia , Mutação , Células NIH 3T3 , Linhagem , Gravidez , Peixe-Zebra
4.
Cell ; 155(1): 107-20, 2013 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-24074864

RESUMO

Polycomb repressive complex 2 (PRC2) regulates gene expression during lineage specification through trimethylation of lysine 27 on histone H3 (H3K27me3). In Drosophila, polycomb binding sites are dynamic chromatin regions enriched with the histone variant H3.3. Here, we show that, in mouse embryonic stem cells (ESCs), H3.3 is required for proper establishment of H3K27me3 at the promoters of developmentally regulated genes. Upon H3.3 depletion, these promoters show reduced nucleosome turnover measured by deposition of de novo synthesized histones and reduced PRC2 occupancy. Further, we show H3.3-dependent interaction of PRC2 with the histone chaperone, Hira, and that Hira localization to chromatin requires H3.3. Our data demonstrate the importance of H3.3 in maintaining a chromatin landscape in ESCs that is important for proper gene regulation during differentiation. Moreover, our findings support the emerging notion that H3.3 has multiple functions in distinct genomic locations that are not always correlated with an "active" chromatin state.


Assuntos
Células-Tronco Embrionárias/metabolismo , Complexo Repressor Polycomb 2/metabolismo , Animais , Proteínas de Ciclo Celular/metabolismo , Diferenciação Celular , Cromatina/metabolismo , Drosophila melanogaster/embriologia , Drosophila melanogaster/metabolismo , Células-Tronco Embrionárias/citologia , Chaperonas de Histonas/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Regiões Promotoras Genéticas , RNA Polimerase II/metabolismo , Fatores de Transcrição/metabolismo , Regulação para Cima
5.
Hum Mol Genet ; 22(4): 769-81, 2013 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-23161749

RESUMO

Mendelian susceptibility to mycobacterial diseases (MSMD) is a rare syndrome, the known genetic etiologies of which impair the production of, or the response to interferon-gamma (IFN-γ). We report here a patient (P1) with MSMD whose cells display mildly impaired responses to IFN-γ, at levels, however, similar to those from MSMD patients with autosomal recessive (AR) partial IFN-γR2 or STAT1 deficiency. Whole-exome sequencing (WES) and Sanger sequencing revealed only one candidate variation for both MSMD-causing and IFN-γ-related genes. P1 carried a heterozygous frame-shift IFNGR2 mutation inherited from her father. We show that the mutant allele is intrinsically loss-of-function and not dominant-negative, suggesting haploinsufficiency at the IFNGR2 locus. We also show that Epstein-Barr virus transformed B lymphocyte cells from 10 heterozygous relatives of patients with AR complete IFN-γR2 deficiency respond poorly to IFN-γ, in some cases as poorly as the cells of P1. Naive CD4(+) T cells and memory IL-4-producing T cells from these individuals also responded poorly to IFN-γ, whereas monocytes and monocyte-derived macrophages (MDMs) did not. This is consistent with the lower levels of expression of IFN-γR2 in lymphoid than in myeloid cells. Overall, MSMD in this patient is probably due to autosomal dominant (AD) IFN-γR2 deficiency, resulting from haploinsufficiency, at least in lymphoid cells. The clinical penetrance of AD IFN-γR2 deficiency is incomplete, possibly due, at least partly, to the variability of cellular responses to IFN-γ in these individuals.


Assuntos
Haploinsuficiência , Infecções por Mycobacterium não Tuberculosas/genética , Receptores de Interferon/genética , Adolescente , Linfócitos B/imunologia , Linfócitos B/metabolismo , Sequência de Bases , Estudos de Casos e Controles , Células Cultivadas , Feminino , Expressão Gênica , Genes Dominantes , Estudos de Associação Genética , Predisposição Genética para Doença , Heterozigoto , Humanos , Interferon gama/fisiologia , Infecções por Mycobacterium/genética , Análise de Sequência com Séries de Oligonucleotídeos , Linhagem , Fosforilação , Processamento de Proteína Pós-Traducional , Receptores de Interferon/deficiência , Análise de Sequência de DNA , Deleção de Sequência
6.
Nat Immunol ; 12(3): 213-21, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21278736

RESUMO

Germline mutations in CYBB, the human gene encoding the gp91(phox) subunit of the phagocyte NADPH oxidase, impair the respiratory burst of all types of phagocytes and result in X-linked chronic granulomatous disease (CGD). We report here two kindreds in which otherwise healthy male adults developed X-linked recessive Mendelian susceptibility to mycobacterial disease (MSMD) syndromes. These patients had previously unknown mutations in CYBB that resulted in an impaired respiratory burst in monocyte-derived macrophages but not in monocytes or granulocytes. The macrophage-specific functional consequences of the germline mutation resulted from cell-specific impairment in the assembly of the NADPH oxidase. This 'experiment of nature' indicates that CYBB is associated with MSMD and demonstrates that the respiratory burst in human macrophages is a crucial mechanism for protective immunity to tuberculous mycobacteria.


Assuntos
Genes Ligados ao Cromossomo X , Predisposição Genética para Doença , Macrófagos/imunologia , Glicoproteínas de Membrana/genética , NADPH Oxidases/genética , Tuberculose/genética , Animais , Células CHO , Cricetinae , Cricetulus , Humanos , Masculino , Mutação , NADPH Oxidase 2 , NADPH Oxidases/imunologia
7.
Hum Mol Genet ; 20(8): 1509-23, 2011 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-21266457

RESUMO

We report a series of 14 patients from 11 kindreds with recessive partial (RP)-interferon (IFN)-γR1 deficiency. The I87T mutation was found in nine homozygous patients from Chile, Portugal and Poland, and the V63G mutation was found in five homozygous patients from the Canary Islands. Founder effects accounted for the recurrence of both mutations. The most recent common ancestors of the patients with the I87T and V63G mutations probably lived 1600 (875-2950) and 500 (200-1275) years ago, respectively. The two alleles confer phenotypes that are similar but differ in terms of IFN-γR1 levels and residual response to IFN-γ. The patients suffered from bacillus Calmette-Guérin-osis (n= 6), environmental mycobacteriosis (n= 6) or tuberculosis (n= 1). One patient did not suffer from mycobacterial infections but had disseminated salmonellosis, which was also present in two other patients. Age at onset of the first environmental mycobacterial disease differed widely between patients, with a mean value of 11.25 ± 9.13 years. Thirteen patients survived until the age of 14.82 ± 11.2 years, and one patient died at the age of 7 years, 9 days after the diagnosis of long-term Mycobacterium avium infection and the initiation of antimycobacterial treatment. Up to 10 patients are currently free of infection with no prophylaxis. The clinical heterogeneity of the 14 patients was not clearly related to either IFNGR1 genotype or the resulting cellular phenotype. RP-IFN-γR1 deficiency is, thus, more common than initially thought and should be considered in both children and adults with mild or severe mycobacterial diseases.


Assuntos
Predisposição Genética para Doença , Infecções por Mycobacterium/genética , Receptores de Interferon/deficiência , Adolescente , Adulto , Sequência de Aminoácidos , Criança , Pré-Escolar , Feminino , Efeito Fundador , Genes Recessivos , Haplótipos , Humanos , Interferon gama/metabolismo , Masculino , Dados de Sequência Molecular , Monócitos/metabolismo , Mutação de Sentido Incorreto , Infecções por Mycobacterium/imunologia , Infecções por Mycobacterium/microbiologia , Mycobacterium avium , Mycobacterium bovis , Osteomielite/genética , Osteomielite/microbiologia , Linhagem , Fenótipo , Fosforilação , Pneumonia Bacteriana/genética , Transporte Proteico , Receptores de Interferon/genética , Receptores de Interferon/imunologia , Fator de Transcrição STAT1/metabolismo , Salmonella , Infecções por Salmonella/genética , Tuberculose/genética , Tuberculose/microbiologia , Tuberculose/mortalidade , Adulto Jovem , Receptor de Interferon gama
8.
Pediatr Infect Dis J ; 30(4): 352-5, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20962705

RESUMO

STAT-1 (Signal Transducer and Activator of Transcription-1) is a key signaling component of interferon gamma responses. We present long-term manifestations in siblings with a mutation in the STAT1 gene, which include invasive salmonellosis, recurrent severe respiratory syncytial virus pneumonitis, and hepatosplenic mycobacterial disease, and we summarize all other reported cases with STAT-1 deficiency.


Assuntos
Infecções por Vírus Respiratório Sincicial/imunologia , Fator de Transcrição STAT1/deficiência , Infecções por Salmonella/imunologia , Tuberculose Hepática/imunologia , Tuberculose Esplênica/imunologia , Adolescente , Feminino , Humanos , Masculino , Pneumonia/imunologia , Pneumonia/patologia , Pneumonia/virologia , Infecções por Vírus Respiratório Sincicial/patologia , Infecções por Salmonella/patologia , Irmãos , Tuberculose Hepática/patologia , Tuberculose Esplênica/patologia
9.
Medicine (Baltimore) ; 89(6): 381-402, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21057261

RESUMO

Interleukin-12 receptor ß1 (IL-12Rß1) deficiency is the most common form of Mendelian susceptibility to mycobacterial disease (MSMD). We undertook an international survey of 141 patients from 102 kindreds in 30 countries. Among 102 probands, the first infection occurred at a mean age of 2.4 years. In 78 patients, this infection was caused by Bacille Calmette-Guérin (BCG; n = 65), environmental mycobacteria (EM; also known as atypical or nontuberculous mycobacteria) (n = 9) or Mycobacterium tuberculosis (n = 4). Twenty-two of the remaining 24 probands initially presented with nontyphoidal, extraintestinal salmonellosis. Twenty of the 29 genetically affected sibs displayed clinical signs (69%); however 8 remained asymptomatic (27%). Nine nongenotyped sibs with symptoms died. Recurrent BCG infection was diagnosed in 15 cases, recurrent EM in 3 cases, recurrent salmonellosis in 22 patients. Ninety of the 132 symptomatic patients had infections with a single microorganism. Multiple infections were diagnosed in 40 cases, with combined mycobacteriosis and salmonellosis in 36 individuals. BCG disease strongly protected against subsequent EM disease (p = 0.00008). Various other infectious diseases occurred, albeit each rarely, yet candidiasis was reported in 33 of the patients (23%). Ninety-nine patients (70%) survived, with a mean age at last follow-up visit of 12.7 years ± 9.8 years (range, 0.5-46.4 yr). IL-12Rß1 deficiency is characterized by childhood-onset mycobacteriosis and salmonellosis, rare recurrences of mycobacterial disease, and more frequent recurrence of salmonellosis. The condition has higher clinical penetrance, broader susceptibility to infections, and less favorable outcome than previously thought.


Assuntos
Subunidade beta 1 de Receptor de Interleucina-12/deficiência , Adolescente , Adulto , Fatores Etários , Criança , Pré-Escolar , Citocinas/sangue , Feminino , Genótipo , Humanos , Lactente , Recém-Nascido , Subunidade beta 1 de Receptor de Interleucina-12/genética , Masculino , Pessoa de Meia-Idade , Infecções por Mycobacterium não Tuberculosas/epidemiologia , Infecções por Mycobacterium não Tuberculosas/genética , Mycobacterium bovis/isolamento & purificação , Mycobacterium tuberculosis/isolamento & purificação , Micobactérias não Tuberculosas/isolamento & purificação , Análise de Sobrevida
10.
Cell ; 140(5): 678-91, 2010 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-20211137

RESUMO

The incorporation of histone H3 variants has been implicated in the epigenetic memory of cellular state. Using genome editing with zinc-finger nucleases to tag endogenous H3.3, we report genome-wide profiles of H3 variants in mammalian embryonic stem cells and neuronal precursor cells. Genome-wide patterns of H3.3 are dependent on amino acid sequence and change with cellular differentiation at developmentally regulated loci. The H3.3 chaperone Hira is required for H3.3 enrichment at active and repressed genes. Strikingly, Hira is not essential for localization of H3.3 at telomeres and many transcription factor binding sites. Immunoaffinity purification and mass spectrometry reveal that the proteins Atrx and Daxx associate with H3.3 in a Hira-independent manner. Atrx is required for Hira-independent localization of H3.3 at telomeres and for the repression of telomeric RNA. Our data demonstrate that multiple and distinct factors are responsible for H3.3 localization at specific genomic locations in mammalian cells.


Assuntos
Histonas/análise , Telômero/química , Animais , Sítios de Ligação , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Células-Tronco Embrionárias/metabolismo , Genoma , Chaperonas de Histonas/genética , Chaperonas de Histonas/metabolismo , Histonas/genética , Histonas/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Telômero/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Sítio de Iniciação de Transcrição
11.
Am J Med Genet A ; 152A(3): 622-9, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20186794

RESUMO

Mendelian susceptibility to mycobacterial disease (MSMD) is a rare primary immunodeficiency associated with clinical disease caused by weakly virulent mycobacterial species. Interferon gamma receptor 1 (IFN-gammaR1) deficiency is a genetic etiology of MSMD. We describe the clinical and genetic features of a 7-year-old Italian boy suffering from MSMD associated with a complex phenotype, including neonatal hyperglycemia, neuromuscular disease, and dysmorphic features. The child also developed necrotizing pneumonia caused by Rhodococcus equi. The child is homozygous for a nonsense mutation in exon 3 of IFNGR1 as a result of paternal uniparental disomy (UPD) of the entire chromosome 6. This is the first reported case of uniparental disomy resulting in a complex phenotype including MSMD.


Assuntos
Anormalidades Múltiplas/genética , Cromossomos Humanos Par 6/genética , Infecções por Mycobacterium/genética , Receptores de Interferon/deficiência , Receptores de Interferon/genética , Dissomia Uniparental/genética , Infecções por Actinomycetales/genética , Criança , Códon sem Sentido , Análise Mutacional de DNA , Éxons , Pai , Feminino , Homozigoto , Humanos , Masculino , Linhagem , Fenótipo , Rhodococcus equi , Síndrome , Receptor de Interferon gama
12.
Hum Mol Genet ; 19(3): 434-44, 2010 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-19880857

RESUMO

IFN-gammaR1 deficiency is a genetic etiology of Mendelian susceptibility to mycobacterial diseases, and includes two forms of complete recessive deficiency, with or without cell surface expression, and two forms of partial deficiency, dominant or recessive. We report here a novel form of partial and recessive Interferon gamma receptor 1 (IFN-gammaR1) deficiency, which is almost as severe as complete deficiency. The patient is homozygous for a mutation of the initiation codon (M1K). No detectable expression and function of IFN-gammaR1 were found in the patient's fibroblasts. However, IFN-gammaR1 expression was found to be impaired, but not abolished, on the EBV-transformed B cells, which could respond weakly to IFN-gamma. The mechanism underlying this weak expression involves leaky translation initiation at both non-AUG codons and the third AUG codon at position 19. It results in the residual expression of IFN-gammaR1 protein of normal molecular weight and function. The residual IFN-gamma signaling documented in this novel form of partial IFN-gammaR1 deficiency was not ubiquitous and was milder than that seen in other forms of partial IFN-gammaR1 deficiency, accounting for the more severe clinical phenotype of the patient, which was almost as severe as that of patients with complete deficiency.


Assuntos
Códon de Iniciação , Mutação em Linhagem Germinativa , Infecções por Mycobacterium/genética , Receptores de Interferon/deficiência , Receptores de Interferon/genética , Linfócitos B/metabolismo , Linhagem Celular , Células Cultivadas , Criança , Feminino , Fibroblastos/metabolismo , Predisposição Genética para Doença , Humanos , Interferon gama/metabolismo , Mutação de Sentido Incorreto , Infecções por Mycobacterium/metabolismo , Infecções por Mycobacterium/microbiologia , Especificidade da Espécie , Receptor de Interferon gama
13.
Int J Infect Dis ; 14(2): e167-70, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19880337

RESUMO

Disseminated disease caused by non-tuberculous, environmental mycobacteria (EM) reflects impaired host immunity. Disseminated disease caused by Mycobacterium scrofulaceum has primarily been reported in patients with AIDS. Moreover, observing M. scrofulaceum as the agent of localized disease in childhood has become increasingly rare. We report the first case of disseminated disease caused by M. scrofulaceum in a child with inherited interferon-gamma receptor 1 (IFN-gammaR1) complete deficiency. As in this case, mycobacterial bone infections in IFN-gammaR1 deficiency can sometimes mimic the clinical picture of chronic recurrent multifocal osteomyelitis.


Assuntos
Síndromes de Imunodeficiência/complicações , Infecções por Mycobacterium não Tuberculosas , Mycobacterium scrofulaceum/isolamento & purificação , Receptores de Interferon/deficiência , Tuberculose Osteoarticular , Pré-Escolar , Pé/microbiologia , Pé/patologia , Mãos/microbiologia , Mãos/patologia , Humanos , Perna (Membro)/microbiologia , Perna (Membro)/patologia , Masculino , Infecções por Mycobacterium não Tuberculosas/microbiologia , Infecções por Mycobacterium não Tuberculosas/patologia , Tuberculose Osteoarticular/microbiologia , Tuberculose Osteoarticular/patologia , Receptor de Interferon gama
14.
J Clin Invest ; 119(6): 1502-14, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19436109

RESUMO

Complete STAT1 deficiency is an autosomal recessive primary immunodeficiency caused by null mutations that abolish STAT1-dependent cellular responses to both IFN-alpha/beta and IFN-gamma. Affected children suffer from lethal intracellular bacterial and viral diseases. Here we report a recessive form of partial STAT1 deficiency, characterized by impaired but not abolished IFN-alpha/beta and IFN-gamma signaling. Two affected siblings suffered from severe but curable intracellular bacterial and viral diseases. Both were homozygous for a missense STAT1 mutation: g.C2086T (P696S). This STAT1 allele impaired the splicing of STAT1 mRNA, probably by disrupting an exonic splice enhancer. The misspliced forms were not translated into a mature protein. The allele was hypofunctional, because residual full-length mRNA production resulted in low but detectable levels of normally functional STAT1 proteins. The P696S amino acid substitution was not detrimental. The patients' cells, therefore, displayed impaired but not abolished responses to both IFN-alpha and IFN-gamma. We also show that recessive STAT1 deficiencies impaired the IL-27 and IFN-lambda1 signaling pathways, possibly contributing to the predisposition to bacterial and viral infections, respectively. Partial recessive STAT1 deficiency is what we believe to be a novel primary immunodeficiency, resulting in impairment of the response to at least 4 cytokines (IFN-alpha/beta, IFN-gamma, IFN-lambda1, and IL-27). It should be considered in patients with unexplained, severe, but curable intracellular bacterial and viral infections.


Assuntos
Fator de Transcrição STAT1/deficiência , Fator de Transcrição STAT1/metabolismo , Alelos , Processamento Alternativo/genética , Aminoácidos/genética , Aminoácidos/metabolismo , Sequência de Bases , Células Cultivadas , Feminino , Humanos , Interferons/genética , Interferons/metabolismo , Masculino , Mutação/genética , Linhagem , RNA Mensageiro/genética , Fator de Transcrição STAT1/genética , Irmãos
15.
Pediatr Infect Dis J ; 28(7): 658-60, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19451859

RESUMO

Interferon gamma receptor deficiency is a rare autosomal recessive inherited disorder, with poor prognosis due to early-onset, recurrent, and disseminated mycobacterial infections. Hematopoietic stem cell transplantation (HSCT), the only curative treatment, is particularly difficult in these patients owing to a high rate of graft rejection. We report the first successful hematopoietic stem cell transplantation with an unrelated donor, performed in a schoolgirl with severe interferon gamma receptor 1deficiency caused by a novel mutation.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Síndromes de Imunodeficiência/complicações , Infecção por Mycobacterium avium-intracellulare/diagnóstico , Infecção por Mycobacterium avium-intracellulare/terapia , Receptores de Interferon/deficiência , Antibacterianos/uso terapêutico , Criança , Feminino , Humanos , Síndromes de Imunodeficiência/diagnóstico , Complexo Mycobacterium avium/isolamento & purificação , Resultado do Tratamento , Receptor de Interferon gama
16.
J Exp Med ; 205(8): 1729-37, 2008 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-18625743

RESUMO

Germline mutations may cause human disease by various mechanisms. Missense and other in-frame mutations may be deleterious because the mutant proteins are not correctly targeted, do not function correctly, or both. We studied a child with mycobacterial disease caused by homozygosity for a novel in-frame microinsertion in IFNGR2. In cells transfected with the mutant allele, most of the interferon gamma receptor 2 (IFN-gamma R2) protein was retained within the cell, and that expressed on the cell surface had an abnormally high molecular weight (MW). The misfolding mutation was not gain-of-glycosylation, as it created no new N-glycosylation site. The mutant IFNGR2 allele was null, as the patient's cells did not respond to IFN-gamma. Based on the well-established relationship between protein N-glycosylation and protein quality control processes, we tested 29 compounds affecting maturation by N-glycosylation in the secretory pathway. Remarkably, up to 13 of these compounds reduced the MW of surface-expressed mutant IFN-gamma R2 molecules and restored cellular responsiveness to IFN-gamma. Modifiers of N-glycosylation may therefore complement human cells carrying in-frame and misfolding, but not necessarily gain-of-glycosylation, mutations in genes encoding proteins subject to trafficking via the secretory pathway. Some of these compounds are available for clinical use, paving the way for clinical trials of chemical complementation for various human genetic traits.


Assuntos
Mutação , Receptores de Interferon/química , Receptores de Interferon/genética , Alelos , Sequência de Aminoácidos , Sequência de Bases , Linhagem Celular , Pré-Escolar , Consanguinidade , DNA/genética , Feminino , Teste de Complementação Genética , Glicosilação , Homozigoto , Humanos , Masculino , Mutagênese Insercional , Infecção por Mycobacterium avium-intracellulare/genética , Infecção por Mycobacterium avium-intracellulare/imunologia , Linhagem , Fenótipo , Dobramento de Proteína , Receptores de Interferon/deficiência , Deleção de Sequência , Transfecção
17.
Immunol Rev ; 226: 29-40, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19161414

RESUMO

Interferon (IFN) was originally identified as a substance 'interfering' with viral replication in vitro. The first IFNs to be identified were classified as type I IFNs (IFN-alpha/beta and related molecules), two other types have since been identified: type II IFN (IFN-gamma) and type III IFNs (IFN-lambda). Each IFN binds to one of three type-specific receptors. In the mouse model of experimental infections in vivo, IFN-alpha/beta are essential for immunity to most viruses tested, whereas IFN-gamma is important for immunity to a smaller number of viruses, together with bacteria, fungi, and parasites, consistent with IFN-gamma acting as the 'macrophage activating factor.' The precise role of IFN-lambda remains unclear. In recent years, inborn errors affecting the production of, or the response to, IFNs have been reported in human patients, shedding light onto the function of IFNs in natura. Disorders of IFN-gamma production, caused by IL12B, IL12RB1, and specific NEMO mutations, or of IFN-gamma responses, caused by IFNGR1, IFNGR2, and dominant STAT1 mutations, confer predisposition to mycobacterial disease in patients resistant to most viruses. By contrast, disorders of IFN-alpha/beta and IFN-lambda production, caused by UNC93B1 and TLR3 mutations, confer predisposition to herpes simplex encephalitis (HSE) in otherwise healthy patients. Consistently, patients with impaired responses to IFN-alpha/beta, IFN-gamma, and presumably IFN-lambda (carrying recessive mutations in STAT1), or with impaired responses to IFN-alpha/beta and impaired IFN-gamma production (carrying mutations in TYK2), or with impaired production of IFN-alpha/beta, IFN-gamma, and IFN-lambda (carrying specific mutations in NEMO), are vulnerable to mycobacterial and viral infections, including HSE. These experiments of nature suggest that the three types of IFNs play at least two different roles in host defense. IFN-gamma is essential for anti-mycobacterial immunity, whereas IFN-alpha/beta and IFN-lambda are essential for anti-viral immunity. Future studies in humans aim to define the specific roles of IFN-alpha/beta and IFN-lambda types and individual molecules in host defense in natura.


Assuntos
Infecções/imunologia , Interferons/imunologia , Animais , Citocinas/genética , Citocinas/imunologia , Predisposição Genética para Doença , Humanos , Infecções/genética , Infecções/microbiologia , Infecções/virologia , Interferon-alfa/genética , Interferon-alfa/imunologia , Interferon beta/genética , Interferon beta/imunologia , Interferon gama/genética , Interferon gama/imunologia , Interferons/genética , Camundongos , Infecções por Mycobacterium/genética , Infecções por Mycobacterium/imunologia , Viroses/genética , Viroses/imunologia
18.
Science ; 317(5844): 1522-7, 2007 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-17872438

RESUMO

Some Toll and Toll-like receptors (TLRs) provide immunity to experimental infections in animal models, but their contribution to host defense in natural ecosystems is unknown. We report a dominant-negative TLR3 allele in otherwise healthy children with herpes simplex virus 1 (HSV-1) encephalitis. TLR3 is expressed in the central nervous system (CNS), where it is required to control HSV-1, which spreads from the epithelium to the CNS via cranial nerves. TLR3 is also expressed in epithelial and dendritic cells, which apparently use TLR3-independent pathways to prevent further dissemination of HSV-1 and to provide resistance to other pathogens in TLR3-deficient patients. Human TLR3 appears to be redundant in host defense to most microbes but is vital for natural immunity to HSV-1 in the CNS, which suggests that neurotropic viruses have contributed to the evolutionary maintenance of TLR3.


Assuntos
Encefalite por Herpes Simples/genética , Encefalite por Herpes Simples/imunologia , Herpesvirus Humano 1 , Receptor 3 Toll-Like/deficiência , Receptor 3 Toll-Like/genética , Alelos , Linfócitos T CD8-Positivos/imunologia , Linhagem Celular , Pré-Escolar , Células Dendríticas/imunologia , Feminino , Fibroblastos/imunologia , Fibroblastos/metabolismo , Fibroblastos/virologia , Genes Dominantes , Herpesvirus Humano 1/fisiologia , Heterozigoto , Humanos , Imunidade Inata , Lactente , Interferons/biossíntese , Queratinócitos/imunologia , Células Matadoras Naturais/imunologia , Leucócitos Mononucleares/imunologia , Mutação , Poli I-C/farmacologia , Receptor 3 Toll-Like/química , Receptor 3 Toll-Like/fisiologia
19.
Biochimie ; 89(6-7): 878-83, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17561326

RESUMO

Type I interferons (IFN-alpha/beta and related molecules) are essential for protective immunity to experimental infection by numerous viruses in the mouse model. In recent years, human primary immunodeficiencies affecting either the production of (UNC-93B deficiency) or the response to (STAT1 and TYK2 deficiencies) these IFNs have been reported. Affected patients are highly susceptible to certain viruses. Patients with STAT1 or TYK2 deficiency are susceptible to multiple viruses, including herpes simplex virus-1 (HSV-1), whereas UNC-93B-deficient patients present isolated HSV-1 encephalitis. However, these immunological defects are not limited to type I IFN-mediated immunity. Impaired type II IFN (IFN-gamma)-mediated immunity plays no more than a minor role in the pathogenesis of viral diseases in these patients, but the contribution of impaired type III IFN (IFN-lambda)-mediated immunity remains to be determined. These novel inherited disorders strongly suggest that type I IFN-mediated immunity is essential for protection against natural infections caused by several viruses in humans.


Assuntos
Síndromes de Imunodeficiência/imunologia , Animais , Antivirais/química , Predisposição Genética para Doença , Herpesviridae/metabolismo , Herpesvirus Humano 1/metabolismo , Humanos , Sistema Imunitário , Imunidade Inata , Síndromes de Imunodeficiência/virologia , Proteínas de Membrana Transportadoras/metabolismo , Modelos Biológicos , Prognóstico , Fator de Transcrição STAT1/metabolismo , TYK2 Quinase/metabolismo
20.
J Allergy Clin Immunol ; 120(1): 32-8, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17544093

RESUMO

A few known primary immunodeficiencies confer predisposition to clinical disease caused by weakly virulent mycobacteria, such as BCG vaccines (regional disease, known as BCG-itis, or disseminated disease, known as BCG-osis), or more virulent mycobacteria, such as Mycobacterium tuberculosis (pulmonary and disseminated tuberculosis). We investigated the clinical and genetic features of a 12-year-old boy with both recurrent BCG-osis and disseminated tuberculosis. The patient's phagocytic cells produced no O(2)(-). A hemizygous splice mutation was found in intron 5 of CYBB, leading to a diagnosis of X-linked chronic granulomatous disease. Chronic granulomatous disease should be suspected in all children with BCG-osis, even in the absence of nonmycobacterial infectious diseases, and in selected children with recurrent BCG-itis or severe tuberculosis.


Assuntos
Vacina BCG/efeitos adversos , Doença Granulomatosa Crônica/diagnóstico , Tuberculose/diagnóstico , Sequência de Bases , Criança , Diagnóstico Diferencial , Doença Granulomatosa Crônica/complicações , Doença Granulomatosa Crônica/patologia , Humanos , Masculino , Glicoproteínas de Membrana/genética , Dados de Sequência Molecular , Mutação , NADPH Oxidase 2 , NADPH Oxidases/genética , Tuberculose/etiologia
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