RESUMO
Deletion 1p36 (del1p36) syndrome is the most common human disorder resulting from a terminal autosomal deletion. This condition is molecularly and clinically heterogeneous. Deletions involving two non-overlapping regions, known as the distal (telomeric) and proximal (centromeric) critical regions, are sufficient to cause the majority of the recurrent clinical features, although with different facial features and dysmorphisms. SPEN encodes a transcriptional repressor commonly deleted in proximal del1p36 syndrome and is located centromeric to the proximal 1p36 critical region. Here, we used clinical data from 34 individuals with truncating variants in SPEN to define a neurodevelopmental disorder presenting with features that overlap considerably with those of proximal del1p36 syndrome. The clinical profile of this disease includes developmental delay/intellectual disability, autism spectrum disorder, anxiety, aggressive behavior, attention deficit disorder, hypotonia, brain and spine anomalies, congenital heart defects, high/narrow palate, facial dysmorphisms, and obesity/increased BMI, especially in females. SPEN also emerges as a relevant gene for del1p36 syndrome by co-expression analyses. Finally, we show that haploinsufficiency of SPEN is associated with a distinctive DNA methylation episignature of the X chromosome in affected females, providing further evidence of a specific contribution of the protein to the epigenetic control of this chromosome, and a paradigm of an X chromosome-specific episignature that classifies syndromic traits. We conclude that SPEN is required for multiple developmental processes and SPEN haploinsufficiency is a major contributor to a disorder associated with deletions centromeric to the previously established 1p36 critical regions.
Assuntos
Transtornos Cromossômicos/genética , Cromossomos Humanos Par 1/genética , Cromossomos Humanos X/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a RNA/genética , Adolescente , Transtorno do Espectro Autista/genética , Transtorno do Espectro Autista/patologia , Criança , Pré-Escolar , Deleção Cromossômica , Transtornos Cromossômicos/fisiopatologia , Metilação de DNA/genética , Epigênese Genética/genética , Feminino , Haploinsuficiência/genética , Humanos , Deficiência Intelectual/genética , Deficiência Intelectual/fisiopatologia , Masculino , Transtornos do Neurodesenvolvimento/genética , Transtornos do Neurodesenvolvimento/fisiopatologia , Fenótipo , Adulto JovemRESUMO
Casitas B-lineage lymphoma (CBL) encodes an adaptor protein with E3-ligase activity negatively controlling intracellular signaling downstream of receptor tyrosine kinases. Somatic CBL mutations play a driver role in a variety of cancers, particularly myeloid malignancies, whereas germline defects in the same gene underlie a RASopathy having clinical overlap with Noonan syndrome (NS) and predisposing to juvenile myelomonocytic leukemia and vasculitis. Other features of the disorder include cardiac defects, postnatal growth delay, cryptorchidism, facial dysmorphisms, and predisposition to develop autoimmune disorders. Here we report a novel CBL variant (c.1202G>T; p.Cys401Phe) occurring de novo in a subject with café-au-lait macules, feeding difficulties, mild dysmorphic features, psychomotor delay, autism spectrum disorder, thrombocytopenia, hepatosplenomegaly, and recurrent hypertransaminasemia. The identified variant affects an evolutionarily conserved residue located in the RING finger domain, a known mutational hot spot of both germline and somatic mutations. Functional studies documented enhanced EGF-induced ERK phosphorylation in transiently transfected COS1 cells. The present findings further support the association of pathogenic CBL variants with immunological and hematological manifestations in the context of a presentation with only minor findings reminiscent of NS or a clinically related RASopathy.
Assuntos
Mutação em Linhagem Germinativa , Proteínas Proto-Oncogênicas c-cbl , Humanos , Proteínas Proto-Oncogênicas c-cbl/genética , Mutação em Linhagem Germinativa/genética , Masculino , Síndrome de Noonan/genética , Síndrome de Noonan/patologia , Transtorno do Espectro Autista/genética , Transtorno do Espectro Autista/patologia , Transtorno do Espectro Autista/imunologia , Transtorno do Espectro Autista/sangue , Predisposição Genética para Doença , Pré-Escolar , Criança , Animais , Fenótipo , Células COS , Trombocitopenia/genética , Trombocitopenia/patologiaRESUMO
Bardet-Biedl syndrome (BBS) is a rare recessive multisystem disorder characterized by retinitis pigmentosa, obesity, postaxial polydactyly, cognitive deficits, and genitourinary defects. BBS is clinically variable and genetically heterogeneous, with 26 genes identified to contribute to the disorder when mutated, the majority encoding proteins playing role in primary cilium biogenesis, intraflagellar transport, and ciliary trafficking. Here, we report on an 18-year-old boy with features including severe photophobia and central vision loss since childhood, hexadactyly of the right foot and a supernumerary nipple, which were suggestive of BBS. Genetic analyses using targeted resequencing and exome sequencing failed to provide a conclusive genetic diagnosis. Whole-genome sequencing (WGS) allowed us to identify compound heterozygosity for a missense variant and a large intragenic deletion encompassing exon 12 in BBS9 as underlying the condition. We assessed the functional impact of the identified variants and demonstrated that they impair BBS9 function, with significant consequences for primary cilium formation and morphology. Overall, this study further highlights the usefulness of WGS in the diagnostic workflow of rare diseases to reach a definitive diagnosis. This report also remarks on a requirement for functional validation analyses to more effectively classify variants that are identified in the frame of the diagnostic workflow.
Assuntos
Síndrome de Bardet-Biedl , Sequenciamento Completo do Genoma , Síndrome de Bardet-Biedl/genética , Síndrome de Bardet-Biedl/diagnóstico , Humanos , Masculino , Adolescente , Cílios/patologia , Cílios/genética , Proteínas do CitoesqueletoRESUMO
BRAFV600 mutations are the most common oncogenic alterations in melanoma cells, supporting proliferation, invasion, metastasis and immune evasion. In patients, these aberrantly activated cellular pathways are inhibited by BRAFi whose potent antitumor effect and therapeutic potential are dampened by the development of resistance. Here, by using primary melanoma cell lines, generated from lymph node lesions of metastatic patients, we show that the combination of two FDA-approved drugs, the histone deacetylate inhibitor (HDCAi) romidepsin and the immunomodulatory agent IFN-α2b, reduces melanoma proliferation, long-term survival and invasiveness and overcomes acquired resistance to the BRAFi vemurafenib (VEM). Targeted resequencing revealed that each VEM-resistant melanoma cell line and the parental counterpart are characterized by a distinctive and similar genetic fingerprint, shaping the differential and specific antitumor modulation of MAPK/AKT pathways by combined drug treatment. By using RNA-sequencing and functional in vitro assays, we further report that romidepsin-IFN-α2b treatment restores epigenetically silenced immune signals, modulates MITF and AXL expression and induces both apoptosis and necroptosis in sensitive and VEM-resistant primary melanoma cells. Moreover, the immunogenic potential of drug-treated VEM-resistant melanoma cells results significantly enhanced, given the increased phagocytosis rate of these cells by dendritic cells, which in turn exhibit also a selective down-modulation of the immune checkpoint TIM-3. Overall, our results provide evidence that combined epigenetic-immune drugs can overcome VEM resistance of primary melanoma cells by oncogenic and immune pathways reprogramming, and pave the way for rapidly exploiting this combination to improve BRAFi-resistant metastatic melanoma treatment, also via reinforcement of immune checkpoint inhibitor therapy.
Assuntos
Interferon Tipo I , Melanoma , Humanos , Vemurafenib/farmacologia , Vemurafenib/uso terapêutico , Resistencia a Medicamentos Antineoplásicos , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas B-raf/genética , Melanoma/tratamento farmacológico , Melanoma/genética , Melanoma/patologia , Linhagem Celular TumoralRESUMO
Inherited retinal degeneration (IRD) represents a clinically variable and genetically heterogeneous group of disorders characterized by photoreceptor dysfunction. These diseases typically present with progressive severe vision loss and variable onset, ranging from birth to adulthood. Genomic sequencing has allowed to identify novel IRD-related genes, most of which encode proteins contributing to photoreceptor-cilia biogenesis and/or function. Despite these insights, knowledge gaps hamper a molecular diagnosis in one-third of IRD cases. By exome sequencing in a cohort of molecularly unsolved individuals with IRD, we identified a homozygous splice site variant affecting the transcript processing of TUB, encoding the first member of the Tubby family of bipartite transcription factors, in a sporadic case with retinal dystrophy. A truncating homozygous variant in this gene had previously been reported in a single family with three subjects sharing retinal dystrophy and obesity. The clinical assessment of the present patient documented a slightly increased body mass index and no changes in metabolic markers of obesity, but confirmed the occurrence of retinal detachment. In vitro studies using patient-derived fibroblasts showed the accelerated degradation of the encoded protein and aberrant cilium morphology and biogenesis. These findings definitely link impaired TUB function to retinal dystrophy and provide new data on the clinical characterization of this ultra-rare retinal ciliopathy.
Assuntos
Ciliopatias , Distrofias Retinianas , Humanos , Adulto , Cílios/genética , Retina , Ciliopatias/genética , Distrofias Retinianas/genética , Proteínas/genética , Obesidade , Mutação , LinhagemRESUMO
Biallelic mutations in B3GALT6, coding for a galactosyltransferase involved in the synthesis of glycosaminoglycans (GAGs), have been associated with various clinical conditions, causing spondyloepimetaphyseal dysplasia with joint laxity type 1 (SEMDJL1 or SEMDJL Beighton type), Al-Gazali syndrome (ALGAZ), and a severe progeroid form of Ehlers-Danlos syndrome (EDSSPD2). In the 2017 Ehlers-Danlos syndrome (EDS) classification, Beta3GalT6-related disorders were grouped in the spondylodysplastic EDSs together with spondylodysplastic EDSs due to B4GALT7 and SLC39A13 mutations. Herein, we describe a patient with a previously unreported homozygous pathogenic B3GALT6 variant resulting in a complex phenotype more severe than spondyloepimetaphyseal dysplasia with joint laxity type 1, and having dural ectasia and aortic dilation as additionally associated features, further broadening the phenotypic spectrum of the Beta3GalT6-related syndromes. We also document the utility of repeating sequencing in patients with uninformative exomes, particularly when performed by using "first generations" enrichment capture methods.
Assuntos
Galactosiltransferases/genética , Instabilidade Articular/genética , Osteocondrodisplasias/genética , Anormalidades Múltiplas/genética , Anormalidades Múltiplas/patologia , Adolescente , Adulto , Segmento Anterior do Olho/anormalidades , Segmento Anterior do Olho/patologia , Osso e Ossos/anormalidades , Osso e Ossos/patologia , Criança , Pré-Escolar , Síndrome de Ehlers-Danlos/genética , Síndrome de Ehlers-Danlos/patologia , Feminino , Homozigoto , Humanos , Instabilidade Articular/diagnóstico , Instabilidade Articular/diagnóstico por imagem , Instabilidade Articular/patologia , Instabilidade Articular/fisiopatologia , Mutação/genética , Osteocondrodisplasias/diagnóstico , Osteocondrodisplasias/diagnóstico por imagem , Osteocondrodisplasias/fisiopatologia , Fenótipo , Adulto JovemRESUMO
Aymé-Gripp syndrome (AYGRPS) is a recognizable condition caused by a restricted spectrum of dominantly acting missense mutations affecting the transcription factor MAF. Major clinical features of AYGRPS include congenital cataracts, sensorineural hearing loss, intellectual disability, and a distinctive flat facial appearance. Skeletal abnormalities have also been observed in affected individuals, even though these features have not been assessed systematically. Expanding the series with four additional patients, here we provide a more accurate delineation of the molecular aspects and clinical phenotype, particularly focusing on the skeletal features characterizing this disorder. Apart from previously reported malar flattening and joint limitations, we document that carpal/tarsal and long bone defects, and hip dysplasia occur in affected subjects more frequently than formerly appreciated.
Assuntos
Catarata/genética , Predisposição Genética para Doença , Transtornos do Crescimento/genética , Perda Auditiva Neurossensorial/genética , Deficiência Intelectual/genética , Anormalidades Musculoesqueléticas/genética , Proteínas Proto-Oncogênicas c-maf/genética , Adolescente , Adulto , Catarata/patologia , Criança , Pré-Escolar , Fácies , Feminino , Transtornos do Crescimento/patologia , Perda Auditiva Neurossensorial/patologia , Humanos , Lactente , Deficiência Intelectual/patologia , Masculino , Anormalidades Musculoesqueléticas/patologia , Mutação de Sentido Incorreto/genética , Adulto JovemRESUMO
Signal Transducer and Activator of Transcription 1 (STAT1) is a DNA-binding signal transducer that regulates transcription of specific genes in response to IFNγ and IFNα/ß stimulation. Loss-of-function mutations impairing STAT1 activity are known to confer susceptibility to intracellular bacterial and viral diseases. Conversely, the few known activating mutations of STAT1 allow predisposition to chronic mucocutaneous candidiasis disease, and occur in patients with combined immunodeficiency and defective Th1 and Th17 responses. Here, we report on a de novo gain-of-function (GoF) STAT1 mutation (c.1398C>G, p.Ser466Arg) identified by exome sequencing in an individual with brain calcification, arthritis, recurrent pericarditis, leukopenia, thrombocytopenia and low C3 levels, a phenotype resembling an interferonopathy. The Ser466Arg change affects a highly conserved residue located in the DNA binding domain of the protein and the amino acid substitution was documented to have an activating role both in vitro and in vivo. Altogether, clinical features and functional studies are compatible with hyperactivation of the Interferon pathways, highlighting a role of STAT1 GoF mutation in clinical phenotypes fitting interferonopathies.
Assuntos
Interferons/metabolismo , Mutação/genética , Fator de Transcrição STAT1/genética , Adolescente , Pré-Escolar , Células HEK293 , Humanos , Masculino , FenótipoRESUMO
Primrose syndrome (PS) is a rare disorder characterized by macrocephaly, tall stature, intellectual disability, autistic traits, and disturbances of glucose metabolism with insulin-resistant diabetes and distal muscle wasting occurring in adulthood. The disorder is caused by functional dysregulation of ZBTB20, a transcriptional repressor controlling energetic metabolism and developmental programs. ZBTB20 maps in a genomic region that is deleted in the 3q13.31 microdeletion syndrome, which explains the clinical overlap between the two disorders. A narrow spectrum of amino acid substitutions in a restricted region of ZBTB20 encompassing the first and second zinc-finger motifs have been reported thus far. Here, we characterize clinically and functionally the first truncating mutation [(c.1024delC; p.(Gln342Serfs*42)] and a missense change affecting the third zinc-finger motif of the protein [(c.1931C > T; p.(Thr644Ile)]. Our data document that both mutations have dominant negative impact on wild-type ZBTB20, providing further evidence of the specific behavior of PS-causing mutations on ZBTB20 function.
Assuntos
Anormalidades Múltiplas/genética , Calcinose/genética , Otopatias/genética , Predisposição Genética para Doença , Deficiência Intelectual/genética , Atrofia Muscular/genética , Proteínas do Tecido Nervoso/genética , Fatores de Transcrição/genética , Anormalidades Múltiplas/fisiopatologia , Calcinose/fisiopatologia , Criança , Pré-Escolar , Deleção Cromossômica , Cromossomos Humanos Par 3/genética , Hibridização Genômica Comparativa , Otopatias/fisiopatologia , Feminino , Humanos , Deficiência Intelectual/fisiopatologia , Masculino , Atrofia Muscular/fisiopatologia , Mutação de Sentido Incorreto/genética , Dedos de Zinco/genéticaRESUMO
Transcription factors operate in developmental processes to mediate inductive events and cell competence, and perturbation of their function or regulation can dramatically affect morphogenesis, organogenesis, and growth. We report that a narrow spectrum of amino-acid substitutions within the transactivation domain of the v-maf avian musculoaponeurotic fibrosarcoma oncogene homolog (MAF), a leucine zipper-containing transcription factor of the AP1 superfamily, profoundly affect development. Seven different de novo missense mutations involving conserved residues of the four GSK3 phosphorylation motifs were identified in eight unrelated individuals. The distinctive clinical phenotype, for which we propose the eponym Aymé-Gripp syndrome, is not limited to lens and eye defects as previously reported for MAF/Maf loss of function but includes sensorineural deafness, intellectual disability, seizures, brachycephaly, distinctive flat facial appearance, skeletal anomalies, mammary gland hypoplasia, and reduced growth. Disease-causing mutations were demonstrated to impair proper MAF phosphorylation, ubiquitination and proteasomal degradation, perturbed gene expression in primary skin fibroblasts, and induced neurodevelopmental defects in an in vivo model. Our findings nosologically and clinically delineate a previously poorly understood recognizable multisystem disorder, provide evidence for MAF governing a wider range of developmental programs than previously appreciated, and describe a novel instance of protein dosage effect severely perturbing development.
Assuntos
Catarata/genética , Surdez/genética , Quinase 3 da Glicogênio Sintase/genética , Deficiência Intelectual/genética , Proteínas Proto-Oncogênicas c-maf/genética , Catarata/patologia , Síndrome de Down/genética , Síndrome de Down/patologia , Humanos , Deficiência Intelectual/patologia , Mutação , Fenótipo , Fosforilação , Convulsões/genética , Convulsões/patologiaRESUMO
RASopathies are a group of rare, clinically related conditions affecting development and growth, and are caused by germline mutations in genes encoding signal transducers and modulators with a role in the RAS signaling network. These disorders share facial dysmorphia, short stature, variable cognitive deficits, skeletal and cardiac defects, and a variable predisposition to malignancies. Here, we report on a de novo 10-nucleotide-long deletion in HRAS (c.481_490delGGGACCCTCT, NM_176795.4; p.Leu163ProfsTer52, NP_789765.1) affecting transcript processing as a novel event underlying a RASopathy characterized by developmental delay, intellectual disability and autistic features, distinctive coarse facies, reduced growth, and ectodermal anomalies. Molecular and biochemical studies demonstrated that the deletion promotes constitutive retention of exon IDX, which is generally skipped during HRAS transcript processing, and results in a stable and mildly hyperactive GDP/GTP-bound protein that is constitutively targeted to the plasma membrane. Our findings document a new mechanism leading to altered HRAS function that underlies a previously unappreciated phenotype within the RASopathy spectrum.
Assuntos
Deficiências do Desenvolvimento/genética , Regulação Neoplásica da Expressão Gênica , Genes ras , Proteínas Proto-Oncogênicas p21(ras)/genética , Animais , Transtorno Autístico/genética , Células COS , Membrana Celular/metabolismo , Criança , Pré-Escolar , Chlorocebus aethiops , Éxons , Fácies , Deleção de Genes , Mutação em Linhagem Germinativa , Humanos , Deficiência Intelectual/genética , Masculino , Fenótipo , RNA Mensageiro/metabolismo , Transdução de SinaisRESUMO
Loss-of-function mutations in PAK3 contribute to non-syndromic X-linked intellectual disability (NS-XLID) by affecting dendritic spine density and morphology. Linkage analysis in a three-generation family with affected males showing ID, agenesis of corpus callosum, cerebellar hypoplasia, microcephaly and ichthyosis, revealed a candidate disease locus in Xq21.33q24 encompassing over 280 genes. Subsequent to sequencing all coding exons of the X chromosome, we identified a single novel variant within the linkage region, affecting a conserved codon of PAK3. Biochemical studies showed that, similar to previous NS-XLID-associated lesions, the predicted amino acid substitution (Lys389Asn) abolished the kinase activity of PAK3. In addition, the introduced residue conferred a dominant-negative function to the protein that drives the syndromic phenotype. Using a combination of in vitro and in vivo studies in zebrafish embryos, we show that PAK3(N389) escapes its physiologic degradation and is able to perturb MAPK signaling via an uncontrolled kinase-independent function, which in turn leads to alterations of cerebral and craniofacial structures in vivo. Our data expand the spectrum of phenotypes associated with PAK3 mutations, characterize a novel mechanism resulting in a dual molecular effect of the same mutation with a complex PAK3 functional deregulation and provide evidence for a direct functional impact of aberrant PAK3 function on MAPK signaling.
Assuntos
Proteínas Quinases Ativadas por Mitógeno/metabolismo , Quinases Ativadas por p21/genética , Proteínas ras/metabolismo , Animais , Éxons/genética , Humanos , Cariotipagem , Proteínas Quinases Ativadas por Mitógeno/genética , Mutação , Transdução de Sinais/genética , Transdução de Sinais/fisiologia , Proteínas ras/genéticaRESUMO
RASopathies, a family of disorders characterized by cardiac defects, defective growth, facial dysmorphism, variable cognitive deficits and predisposition to certain malignancies, are caused by constitutional dysregulation of RAS signalling predominantly through the RAF/MEK/ERK (MAPK) cascade. We report on two germline mutations (p.Gly39dup and p.Val55Met) in RRAS, a gene encoding a small monomeric GTPase controlling cell adhesion, spreading and migration, underlying a rare (2 subjects among 504 individuals analysed) and variable phenotype with features partially overlapping Noonan syndrome, the most common RASopathy. We also identified somatic RRAS mutations (p.Gly39dup and p.Gln87Leu) in 2 of 110 cases of non-syndromic juvenile myelomonocytic leukaemia, a childhood myeloproliferative/myelodysplastic disease caused by upregulated RAS signalling, defining an atypical form of this haematological disorder rapidly progressing to acute myeloid leukaemia. Two of the three identified mutations affected known oncogenic hotspots of RAS genes and conferred variably enhanced RRAS function and stimulus-dependent MAPK activation. Expression of an RRAS mutant homolog in Caenorhabditis elegans enhanced RAS signalling and engendered protruding vulva, a phenotype previously linked to the RASopathy-causing SHOC2(S2G) mutant. Overall, these findings provide evidence of a functional link between RRAS and MAPK signalling and reveal an unpredicted role of enhanced RRAS function in human disease.
Assuntos
Carcinogênese/genética , Mutação/fisiologia , Fenótipo , Proteínas ras/genética , Animais , Caenorhabditis elegans , Estudos de Coortes , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mielomonocítica Juvenil/genética , MAP Quinase Quinase Quinases/metabolismo , Síndrome de Noonan/genética , Proteína Oncogênica v-akt/metabolismo , Transdução de Sinais/genética , Proteínas ras/química , Proteínas ras/metabolismoRESUMO
Wiedemann-Steiner Syndrome (WSS) is an autosomal dominant disorder characterized by hypertrichosis, short stature, intellectual disability, developmental delay, and facial dysmorphism. Since the original reports by Wiedemann and co-workers, and Steiner and Marques, only a few cases have been described. Recently, the clinical variability of the disorder has more precisely been characterized by Jones and co-workers, who also identified heterozygous KMT2A mutations as the molecular defect underlying this condition. Here, we report on a boy with a complex phenotype overlapping WSS but exhibiting epilepsy, feeding difficulties, microcephaly, and congenital immunodeficiency with low levels of immunoglobulins as additional features. Whole exome sequencing allowed identifying a previously unreported de novo KMT2A missense mutation affecting the DNA binding domain of the methyltransferase. This finding expands the clinical phenotype associated with KMT2A mutations to include immunodeficiency and epilepsy as clinically relevant features for this disorder. © 2016 Wiley Periodicals, Inc.
Assuntos
Anormalidades Múltiplas/diagnóstico , Anormalidades Múltiplas/genética , Histona-Lisina N-Metiltransferase/genética , Síndromes de Imunodeficiência/diagnóstico , Síndromes de Imunodeficiência/genética , Mutação de Sentido Incorreto , Proteína de Leucina Linfoide-Mieloide/genética , Fenótipo , Sequência de Aminoácidos , Análise Mutacional de DNA , Eletroencefalografia , Fácies , Estudos de Associação Genética , Heterozigoto , Humanos , Hibridização in Situ Fluorescente , Lactente , Imageamento por Ressonância Magnética , Masculino , SíndromeRESUMO
Noonan syndrome (NS) is a relatively common developmental disorder with a pleomorphic phenotype. Mutations causing NS alter genes encoding proteins involved in the RAS-MAPK pathway. We and others identified Casitas B-lineage lymphoma proto-oncogene (CBL), which encodes an E3-ubiquitin ligase acting as a tumor suppressor in myeloid malignancies, as a disease gene underlying a condition clinically related to NS. Here, we further explored the spectrum of germline CBL mutations and their associated phenotype. CBL mutation scanning performed on 349 affected subjects with features overlapping NS and no mutation in NS genes allowed the identification of five different variants with pathological significance. Among them, two splice-site changes, one in-frame deletion, and one missense mutation affected the RING domain and/or the adjacent linker region, overlapping cancer-associated defects. A novel nonsense mutation generating a v-Cbl-like protein able to enhance signal flow through RAS was also identified. Genotype-phenotype correlation analysis performed on available records indicated that germline CBL mutations cause a variable phenotype characterized by a relatively high frequency of neurological features, predisposition to juvenile myelomonocytic leukemia, and low prevalence of cardiac defects, reduced growth, and cryptorchidism. Finally, we excluded a major contribution of two additional members of the CBL family, CBLB and CBLC, to NS and related disorders.
Assuntos
Variação Genética , Mutação em Linhagem Germinativa , Proteínas Proto-Oncogênicas c-cbl/genética , Pré-Escolar , Feminino , Estudos de Associação Genética , Humanos , Masculino , Síndrome de Noonan/genética , Síndrome de Noonan/fisiopatologia , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas c-cbl/metabolismoRESUMO
FSGS is characterized by the presence of partial sclerosis of some but not all glomeruli. Studies of familial FSGS have been instrumental in identifying podocytes as critical elements in maintaining glomerular function, but underlying mutations have not been identified for all forms of this genetically heterogeneous condition. Here, exome sequencing in members of an index family with dominant FSGS revealed a nonconservative, disease-segregating variant in the PAX2 transcription factor gene. Sequencing in probands of a familial FSGS cohort revealed seven rare and private heterozygous single nucleotide substitutions (4% of individuals). Further sequencing revealed seven private missense variants (8%) in a cohort of individuals with congenital abnormalities of the kidney and urinary tract. As predicted by in silico structural modeling analyses, in vitro functional studies documented that several of the FSGS-associated PAX2 mutations perturb protein function by affecting proper binding to DNA and transactivation activity or by altering the interaction of PAX2 with repressor proteins, resulting in enhanced repressor activity. Thus, mutations in PAX2 may contribute to adult-onset FSGS in the absence of overt extrarenal manifestations. These results expand the phenotypic spectrum associated with PAX2 mutations, which have been shown to lead to congenital abnormalities of the kidney and urinary tract as part of papillorenal syndrome. Moreover, these results indicate PAX2 mutations can cause disease through haploinsufficiency and dominant negative effects, which could have implications for tailoring individualized drug therapy in the future.
Assuntos
Glomerulosclerose Segmentar e Focal/genética , Mutação , Fator de Transcrição PAX2/genética , Adolescente , Adulto , Idade de Início , Idoso , Sequência de Aminoácidos , Sequência de Bases , Estudos de Coortes , Simulação por Computador , Sequência Conservada , Análise Mutacional de DNA , Exoma , Feminino , Glomerulosclerose Segmentar e Focal/metabolismo , Glomerulosclerose Segmentar e Focal/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Moleculares , Dados de Sequência Molecular , Mutação de Sentido Incorreto , Fator de Transcrição PAX2/química , Fator de Transcrição PAX2/metabolismo , Linhagem , Polimorfismo de Nucleotídeo Único , Conformação Proteica , Eletricidade Estática , Anormalidades Urogenitais , Refluxo Vesicoureteral/genética , Adulto JovemRESUMO
RAS signaling plays a key role in controlling appropriate cell responses to extracellular stimuli and participates in early and late developmental processes. Although enhanced flow through this pathway has been established as a major contributor to oncogenesis, recent discoveries have revealed that aberrant RAS activation causes a group of clinically related developmental disorders characterized by facial dysmorphism, a wide spectrum of cardiac disease, reduced growth, variable cognitive deficits, ectodermal and musculoskeletal anomalies, and increased risk for certain malignancies. Here, we report that heterozygous germline mutations in CBL, a tumor-suppressor gene that is mutated in myeloid malignancies and encodes a multivalent adaptor protein with E3 ubiquitin ligase activity, can underlie a phenotype with clinical features fitting or partially overlapping Noonan syndrome (NS), the most common condition of this disease family. Independent CBL mutations were identified in two sporadic cases and two families from among 365 unrelated subjects who had NS or suggestive features and were negative for mutations in previously identified disease genes. Phenotypic heterogeneity and variable expressivity were documented. Mutations were missense changes altering evolutionarily conserved residues located in the RING finger domain or the linker connecting this domain to the N-terminal tyrosine kinase binding domain, a known mutational hot spot in myeloid malignancies. Mutations were shown to affect CBL-mediated receptor ubiquitylation and dysregulate signal flow through RAS. These findings document that germline mutations in CBL alter development to cause a clinically variable condition that resembles NS and that possibly predisposes to malignancies.
Assuntos
Mutação em Linhagem Germinativa/genética , Heterozigoto , Síndrome de Noonan/genética , Proteínas Proto-Oncogênicas c-cbl/genética , Proteínas Supressoras de Tumor/genética , Substituição de Aminoácidos/genética , Sequência de Bases , Análise Mutacional de DNA , Feminino , Humanos , Masculino , Dados de Sequência Molecular , Proteínas Mutantes/genética , FenótipoRESUMO
Despite extensive studies that unraveled ligands and signal transduction pathways triggered by TLRs, little is known about the regulation of TLR gene expression. TLR3 plays a crucial role in the recognition of viral pathogens and induction of immune responses by myeloid DCs. IFN regulatory factor (IRF)-8, a member of the IRF family, is a transcriptional regulator that plays essential roles in the development and function of myeloid lineage, affecting different subsets of myeloid DCs. In this study, we show that IRF-8 negatively controls TLR3 gene expression by suppressing IRF-1- and/or polyinosinic-polycytidylic acid-stimulated TLR3 expression in primary human monocyte-derived DCs (MDDCs). MDDCs expressed TLR3 increasingly during their differentiation from monocytes to DCs with a peak at day 5, when TLR3 expression was further enhanced upon stimulation with polyinosinic-polycytidylic acid and then was promptly downregulated. We found that both IRF-1 and IRF-8 bind the human TLR3 promoter during MDDC differentiation in vitro and in vivo but with different kinetic and functional effects. We demonstrate that IRF-8-induced repression of TLR3 is specifically mediated by ligand-activated Src homology 2 domain-containing protein tyrosine phosphatase association. Indeed, Src homology 2 domain-containing protein tyrosine phosphatase-dephosphorylated IRF-8 bound to the human TLR3 promoter competing with IRF-1 and quashing its activity by recruitment of histone deacetylase 3. Our findings identify IRF-8 as a key player in the control of intracellular viral dsRNA-induced responses and highlight a new mechanism for negative regulation of TLR3 expression that can be exploited to block excessive TLR activation.
Assuntos
Células Dendríticas/imunologia , Regulação para Baixo/imunologia , Fatores Reguladores de Interferon/fisiologia , Células Mieloides/imunologia , Proteína Tirosina Fosfatase não Receptora Tipo 2/metabolismo , Receptor 3 Toll-Like/antagonistas & inibidores , Receptor 3 Toll-Like/genética , Domínios de Homologia de src/imunologia , Células Dendríticas/enzimologia , Células Dendríticas/virologia , Regulação para Baixo/genética , Regulação da Expressão Gênica/imunologia , Humanos , Fatores Reguladores de Interferon/genética , Fatores Reguladores de Interferon/metabolismo , Líquido Intracelular/imunologia , Líquido Intracelular/metabolismo , Líquido Intracelular/virologia , Ligantes , Células Mieloides/enzimologia , Células Mieloides/virologia , Poli I-C/farmacologia , Ligação Proteica/genética , Ligação Proteica/imunologia , Proteína Tirosina Fosfatase não Receptora Tipo 2/fisiologia , RNA Viral/farmacologia , Receptor 3 Toll-Like/metabolismo , Domínios de Homologia de src/genéticaRESUMO
Crucial steps in high-risk human papillomavirus (HR-HPV)-related carcinogenesis are the integration of HR-HPV into the host genome and loss of viral episomes. The mechanisms that promote cervical neoplastic progression are, however, not clearly understood. During HR-HPV infection, the HPV E5 protein is expressed in precancerous stages but not after viral integration. Given that it has been reported that loss of HPV16 episomes and cervical tumor progression are associated with increased expression of antiviral genes that are inducible by type I interferon (IFN), we asked whether E5, expressed in early phases of cervical carcinogenesis, affects IFN-ß signaling. We show that the HPV type 16 (HPV16) E5 protein expression per se stimulates IFN-ß expression. This stimulation is specifically mediated by the induction of interferon regulatory factor 1 (IRF-1) which, in turn, induces transcriptional activation of IRF-1-targeted interferon-stimulated genes (ISGs) as double-stranded RNA-dependent protein kinase R (PKR) and caspase 8. Our data show a new and unexpected role for HR-HPV E5 protein and indicate that HPV16 E5 may contribute to the mechanisms responsible for cervical carcinogenesis in part via stimulation of IFN-ß and an IFN signature, with IRF-1 playing a pivotal role. HPV16 E5 and IRF-1 may thus serve as potential therapeutic targets in HPV-associated premalignant lesions.
Assuntos
Interações Hospedeiro-Patógeno , Papillomavirus Humano 16/imunologia , Fator Regulador 1 de Interferon/metabolismo , Interferon beta/biossíntese , Queratinócitos/imunologia , Proteínas Oncogênicas Virais/metabolismo , Linhagem Celular , Papillomavirus Humano 16/patogenicidade , Humanos , Queratinócitos/virologiaRESUMO
Biofilm at water-oil interface of hypoxic water columns of microcosms, prepared from a lacustrine sample, that used diesel as a carbon source was found to show electrogenic properties. These microcosms named, Liquid Microbial Fuel Cells (L-MFCs) were electrically characterized using a custom electronic analyzer; accurate determination of voltage (V), power density (W/m 2), and current density (A/m2) for both charge and discharge phases was carried out. The instrument made it possible to carry out cell characterizations using resistive loads between 0 Ω (Ohm) and 10 kΩ. During the hypoxic and electrogenic phase, the synthesis of a system of "bacterial piping induction", produced filaments of hundreds of micrometers in which the microbial cells are hosted. Ultrastructural microscopy collected by scanning (SEM), transmission (TEM), immunofluorescence, Thunder Imager 3D, confocal laser scanning (CLSM) microscopy revealed a "myelin like" structure during filamentation processes; this "myelin like" structure exhibited cross-reactivity towards different epitopes of the myelin basic protein (MBP) and Claudin 11 (O4) of human oligodendrocytes. The disclosure of these filamentation processes could be helpful to describe further unconventional microbial structures in aquatic ecosystems and of the animal world. The data that support the findings of this study are openly available in at https://data.mendeley.com/datasets/7d35tj3j96/1.