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1.
Hum Mol Genet ; 31(4): 561-575, 2022 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-34508588

RESUMO

Germline-activating mutations in HRAS cause Costello syndrome (CS), a cancer prone multisystem disorder characterized by reduced postnatal growth. In CS, poor weight gain and growth are not caused by low caloric intake. Here, we show that constitutive plasma membrane translocation and activation of the GLUT4 glucose transporter, via reactive oxygen species-dependent AMP-activated protein kinase α and p38 hyperactivation, occurs in primary fibroblasts of CS patients, resulting in accelerated glycolysis and increased fatty acid synthesis and storage as lipid droplets. An accelerated autophagic flux was also identified as contributing to the increased energetic expenditure in CS. Concomitant inhibition of p38 and PI3K signaling by wortmannin was able to rescue both the dysregulated glucose intake and accelerated autophagic flux. Our findings provide a mechanistic link between upregulated HRAS function, defective growth and increased resting energetic expenditure in CS, and document that targeting p38 and PI3K signaling is able to revert this metabolic dysfunction.


Assuntos
Síndrome de Costello , Síndrome de Costello/genética , Síndrome de Costello/metabolismo , Fibroblastos/metabolismo , Humanos , Oxirredução , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética , Transdução de Sinais/genética
2.
Int J Mol Sci ; 25(16)2024 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-39201250

RESUMO

RASopathies are a group of related genetic disorders caused by mutations in genes within the RAS/MAPK signaling pathway. This pathway is crucial for cell division, growth, and differentiation, and its disruption can lead to a variety of developmental and health issues. RASopathies present diverse clinical features and pose significant diagnostic and therapeutic challenges. Studying the landscape of biomarkers in RASopathies has the potential to improve both clinical practices and the understanding of these disorders. This review provides an overview of recent discoveries in RASopathy molecular profiling, which extend beyond traditional gene mutation analysis. mRNAs, non-coding RNAs, protein expression patterns, and post-translational modifications characteristic of RASopathy patients within pivotal signaling pathways such as the RAS/MAPK, PI3K/AKT/mTOR, and Rho/ROCK/LIMK2/cofilin pathways are summarized. Additionally, the field of metabolomics holds potential for uncovering metabolic signatures associated with specific RASopathies, which are crucial for developing precision medicine. Beyond molecular markers, we also examine the role of histological characteristics and non-invasive physiological assessments in identifying potential biomarkers, as they provide evidence of the disease's effects on various systems. Here, we synthesize key findings and illuminate promising avenues for future research in RASopathy biomarker discovery, underscoring rigorous validation and clinical translation.


Assuntos
Biomarcadores , Proteínas ras , Humanos , Biomarcadores/metabolismo , Proteínas ras/metabolismo , Proteínas ras/genética , Transdução de Sinais , Mutação , Mancha Vinho do Porto/genética , Mancha Vinho do Porto/metabolismo , Mancha Vinho do Porto/patologia , Síndrome de Costello/genética , Síndrome de Costello/metabolismo , Síndrome de Costello/patologia , Displasia Ectodérmica/genética , Displasia Ectodérmica/metabolismo , Displasia Ectodérmica/diagnóstico , Displasia Ectodérmica/patologia , Insuficiência de Crescimento/genética , Insuficiência de Crescimento/metabolismo , Animais , Cardiopatias Congênitas/genética , Cardiopatias Congênitas/metabolismo , Cardiopatias Congênitas/patologia , Fácies
3.
J Neurosci ; 36(1): 142-52, 2016 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-26740656

RESUMO

Increasing evidence implicates abnormal Ras signaling as a major contributor in neurodevelopmental disorders, yet how such signaling causes cortical pathogenesis is unknown. We examined the consequences of aberrant Ras signaling in the developing mouse brain and uncovered several critical phenotypes, including increased production of cortical neurons and morphological deficits. To determine whether these phenotypes are recapitulated in humans, we generated induced pluripotent stem (iPS) cell lines from patients with Costello syndrome (CS), a developmental disorder caused by abnormal Ras signaling and characterized by neurodevelopmental abnormalities, such as cognitive impairment and autism. Directed differentiation toward a neuroectodermal fate revealed an extended progenitor phase and subsequent increased production of cortical neurons. Morphological analysis of mature neurons revealed significantly altered neurite length and soma size in CS patients. This study demonstrates the synergy between mouse and human models and validates the use of iPS cells as a platform to study the underlying cellular pathologies resulting from signaling deficits. SIGNIFICANCE STATEMENT: Increasing evidence implicates Ras signaling dysfunction as a major contributor in psychiatric and neurodevelopmental disorders, such as cognitive impairment and autism, but the underlying cortical cellular pathogenesis remains unclear. This study is the first to reveal human neuronal pathogenesis resulting from abnormal Ras signaling and provides insights into how these phenotypic abnormalities likely contribute to neurodevelopmental disorders. We also demonstrate the synergy between mouse and human models, thereby validating the use of iPS cells as a platform to study underlying cellular pathologies resulting from signaling deficits. Recapitulating human cellular pathologies in vitro facilitates the future high throughput screening of potential therapeutic agents that may reverse phenotypic and behavioral deficits.


Assuntos
Síndrome de Costello/metabolismo , Síndrome de Costello/patologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Neurais/metabolismo , Células-Tronco Neurais/patologia , Proteínas ras/metabolismo , Adolescente , Adulto , Diferenciação Celular , Células Cultivadas , Criança , Pré-Escolar , Feminino , Humanos , Células-Tronco Pluripotentes Induzidas/patologia , Lactente , Masculino , Pessoa de Meia-Idade , Regulação para Cima
4.
Clin Genet ; 92(3): 332-337, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28139825

RESUMO

Costello syndrome (CS) is caused by heterozygous germline HRAS mutations. Most patients share the HRAS mutation c.34G>A (p.Gly12Ser) associated with the typical, relatively homogeneous phenotype. Rarer mutations occurred in individuals with an attenuated phenotype. Although many disease-associated HRAS alterations trigger constitutive activation of HRAS-dependent signalling pathways, additional pathological consequences exist. An infant with failure-to-thrive and hypertrophic cardiomyopathy had a novel de novo HRAS mutation (c.179G>T; p.Gly60Val). He showed subtle dysmorphic findings consistent with attenuated CS and died from presumed cardiac cause. Functional studies revealed that amino acid change p.Gly60Val impairs HRAS binding to effectors PIK3CA, phospholipase C1, and RAL guanine nucleotide dissociation stimulator. In contrast, interaction with effector rapidly accelerated fibrosarcoma (RAF) and regulator NF1 GTPase-activating protein was enhanced. Importantly, expression of HRAS p.Gly60Val in HEK293 cells reduced growth factor sensitivity leading to damped RAF-MAPK and phosphoinositide 3-kinases-AKT signalling response. Our data support the idea that a variable range of dysregulated HRAS-dependent signalling dynamics, rather than static activation of HRAS-dependent signal flow, may underlie the phenotypic variability in CS.


Assuntos
Síndrome de Costello/diagnóstico , Síndrome de Costello/genética , Mutação , Fenótipo , Proteínas Proto-Oncogênicas p21(ras)/genética , Alelos , Substituição de Aminoácidos , Autopsia , Linhagem Celular , Síndrome de Costello/metabolismo , Evolução Fatal , Estudos de Associação Genética , Genótipo , Humanos , Lactente , Masculino , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Transdução de Sinais
5.
Hum Mol Genet ; 23(3): 682-92, 2014 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-24057668

RESUMO

RASopathies are syndromes caused by gain-of-function mutations in the Ras signaling pathway. One of these conditions, Costello syndrome (CS), is typically caused by an activating de novo germline mutation in HRAS and is characterized by a wide range of cardiac, musculoskeletal, dermatological and developmental abnormalities. We report that a majority of individuals with CS have hypo-mineralization of enamel, the outer covering of teeth, and that similar defects are present in a CS mouse model. Comprehensive analysis of the mouse model revealed that ameloblasts, the cells that generate enamel, lacked polarity, and the ameloblast progenitor cells were hyperproliferative. Ras signals through two main effector cascades, the mitogen-activated protein kinase (MAPK) and phosphatidylinositol-3-kinase (PI3K) pathways. To determine through which pathway Ras affects enamel formation, inhibitors targeting either PI3K or MEK 1 and 2 (MEK 1/2), kinases in the MAPK pathway, were utilized. MEK1/2 inhibition rescued the hypo-mineralized enamel, normalized the ameloblast polarity defect and restored normal progenitor cell proliferation. In contrast, PI3K inhibition only corrected the progenitor cell proliferation phenotype. We demonstrate for the first time the central role of Ras signaling in enamel formation in CS individuals and present the mouse incisor as a model system to dissect the roles of the Ras effector pathways in vivo.


Assuntos
Síndrome de Costello/metabolismo , Esmalte Dentário/patologia , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Adolescente , Adulto , Ameloblastos/metabolismo , Ameloblastos/patologia , Animais , Estudos de Casos e Controles , Polaridade Celular , Criança , Pré-Escolar , Estudos de Coortes , Síndrome de Costello/genética , Esmalte Dentário/efeitos dos fármacos , Esmalte Dentário/metabolismo , Esmalte Dentário/ultraestrutura , Modelos Animais de Doenças , Inibidores Enzimáticos/farmacologia , Feminino , Humanos , Lactente , MAP Quinase Quinase Quinase 1/antagonistas & inibidores , MAP Quinase Quinase Quinase 1/metabolismo , Masculino , Camundongos , Camundongos Mutantes , Microscopia Eletrônica de Varredura , Fosfatidilinositol 3-Quinases/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase , Proteínas Proto-Oncogênicas p21(ras)/genética , Transdução de Sinais/genética , Adulto Jovem
6.
J Pediatr ; 170: 322-4, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26778095

RESUMO

Costello syndrome is a rare multisystem disorder caused by mutations in the proto-oncogene HRAS. Failure to thrive is one of its cardinal clinical features. This study documents that individuals with Costello syndrome have increased resting energy expenditure. We speculate this could be one of the potential mechanisms causing failure to thrive.


Assuntos
Síndrome de Costello/complicações , Metabolismo Energético , Insuficiência de Crescimento/etiologia , Descanso/fisiologia , Adolescente , Adulto , Estudos de Casos e Controles , Criança , Pré-Escolar , Síndrome de Costello/metabolismo , Insuficiência de Crescimento/metabolismo , Feminino , Humanos , Masculino , Proto-Oncogene Mas , Adulto Jovem
7.
Am J Med Genet A ; 170(10): 2570-7, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27155212

RESUMO

Noonan, Cardio-facio-cutaneous, and Costello syndromes are disorders of the Ras/MAPK pathway that share many clinical features. This observational and anthropometric study was conducted to describe the key facial features of each syndrome in order to improve discrimination between the three conditions, particularly in young children where diagnosis is most challenging. Direct measurement of the head and face was used to enhance diagnostic accuracy, and identify the most unusual or specific dimensions. The Noonan syndrome cohort included 123 individuals, aged 6 months to 41 years. There were 20 children and adolescents with Cardio-facio-cutaneous syndrome, and 28 individuals with Costello syndrome, aged 1-32 years. The facial phenotypes of these syndromes, particularly Noonan syndrome, are well-described but objective data have not been published in peer-reviewed literature. In this study, subjective observations, in the main, were validated by anthropometry with one exception. In individuals with Costello syndrome, mouth width was normal, thus the impression of wide mouth is likely due to full lips or the mouth being viewed in relation to a narrow lower face. When the three conditions were compared objectively, syndrome-specific pattern profiles showed high concordance in early life. At older ages, Cardio-facio-cutaneous syndrome was distinguished by increased width of the mid/lower face, and reduced growth of maxillary and mandibular dimensions was noted in both Noonan and Costello syndromes. Despite substantial similarities in face shape in older individuals with these two conditions, bulbous nasal tip, full lips, and an apparently wide mouth in those with Costello Syndrome facilitate discrimination from Noonan syndrome. © 2016 Wiley Periodicals, Inc.


Assuntos
Síndrome de Costello/diagnóstico , Displasia Ectodérmica/diagnóstico , Fácies , Insuficiência de Crescimento/diagnóstico , Cardiopatias Congênitas/diagnóstico , Síndrome de Noonan/diagnóstico , Adolescente , Adulto , Fatores Etários , Pesos e Medidas Corporais , Criança , Pré-Escolar , Síndrome de Costello/genética , Síndrome de Costello/metabolismo , Diagnóstico Diferencial , Displasia Ectodérmica/genética , Displasia Ectodérmica/metabolismo , Insuficiência de Crescimento/genética , Insuficiência de Crescimento/metabolismo , Feminino , Cardiopatias Congênitas/genética , Cardiopatias Congênitas/metabolismo , Humanos , Lactente , Masculino , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Síndrome de Noonan/genética , Síndrome de Noonan/metabolismo , Fenótipo , Transdução de Sinais , Adulto Jovem , Proteínas ras/metabolismo
8.
Hum Mol Genet ; 22(8): 1643-53, 2013 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-23335589

RESUMO

Costello syndrome is a congenital disorder comprising a characteristic face, severe feeding difficulties, skeletal, cardiac and skin abnormalities, intellectual disability and predisposition to malignancies. It is caused by heterozygous germline HRAS mutations mostly affecting Gly(12) or Gly(13), which impair HRAS-GTPase activity and result in increased downstream signal flow independent of incoming signals. Functional analyses of rarer HRAS mutations identified in individuals with attenuated Costello syndrome phenotypes revealed altered GDP/GTP nucleotide affinities (p.K117R) and inefficient effector binding (p.E37dup). Thus, both phenotypic and functional variability associated with HRAS mutations are evident. Here, we report on a novel heterozygous HRAS germline mutation (c.187_207dup, p.E63_D69dup) in a girl presenting with a phenotype at the milder end of the Costello syndrome spectrum. The p.E63_D69dup mutation impaired co-precipitation of recombinant HRAS with NF1 GTPase-activating protein (GAP) suggesting constitutive HRAS(E63_D69dup) activation due to GAP insensitivity. Indeed, we identified strongly augmented active HRAS(E63_D69dup) that co-precipitated with effectors RAF1, RAL guanine nucleotide dissociation stimulator and phospholipase C1. However, we could not pull down active HRAS(E63_D69dup) using the target protein PIK3CA, indicating a compromised association between active HRAS(E63_D69dup) and PIK3CA. Accordingly, overexpression of HRAS(E63_D69dup) increased steady-state phosphorylation of MEK1/2 and ERK1/2 downstream of RAF, whereas AKT phosphorylation downstream of phosphoinositide 3-kinase (PI3K) was not enhanced. By analyzing signaling dynamics, we found that HRAS(E63_D69dup) has impaired reagibility to stimuli resulting in reduced and disrupted capacity to transduce incoming signals to the RAF-MAPK and PI3K-AKT cascade, respectively. We suggest that disrupted HRAS reagibility, as we demonstrate for the p.E63_D69dup mutation, is a previously unappreciated molecular pathomechanism underlying Costello syndrome.


Assuntos
Síndrome de Costello/genética , Patologia Molecular , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética , Anormalidades Múltiplas/genética , Anormalidades Múltiplas/patologia , Adolescente , Animais , Classe I de Fosfatidilinositol 3-Quinases , Síndrome de Costello/metabolismo , Síndrome de Costello/patologia , Feminino , Proteínas Ativadoras de GTPase/genética , Duplicação Gênica , Mutação em Linhagem Germinativa , Humanos , Deficiência Intelectual/genética , Deficiência Intelectual/patologia , Sistema de Sinalização das MAP Quinases/genética , Camundongos , Neurofibromina 1/genética , Neurofibromina 1/metabolismo , Fosfatidilinositol 3-Quinases/genética , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Transdução de Sinais
9.
Hum Mol Genet ; 21(22): 4836-44, 2012 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-22869679

RESUMO

The interrelationship between brown adipose tissue (BAT) and white adipose tissue (WAT) is emerging as an important factor in obesity, but the effect of impairing non-shivering thermogenesis in BAT on lipid storage in WAT remains unclear. To address this, we have characterized the metabolic phenotype of a mouse model for Costeff syndrome, in which a point mutation in the mitochondrial membrane protein Opa3 impairs mitochondrial activity. Opa3(L122P) mice displayed an 80% reduction in insulin-like growth factor 1, postnatal growth retardation and hepatic steatosis. A 90% reduction in uncoupling protein 1 (UCP1) expression in interscapular BAT was accompanied by a marked reduction in surface body temperature, with a 2.5-fold elevation in interscapular BAT mass and lipid storage. The sequestration of circulating lipid into BAT resulted in profound reductions in epididymal and retroperitoneal WAT mass, without affecting subcutaneous WAT. The histological appearance and intense mitochondrial staining in intra-abdominal WAT suggest significant 'browning', but with UCP1 expression in WAT of Opa3(L122P) mice only 62% of that in wild-type littermates, any precursor differentiation does not appear to result in thermogenically active beige adipocytes. Thus, we have identified Opa3 as a novel regulator of lipid metabolism, coupling lipid uptake with lipid processing in liver and with thermogenesis in BAT. These findings indicate that skeletal and metabolic impairment in Costeff syndrome may be more significant than previously thought and that uncoupling lipid uptake from lipid metabolism in BAT may represent a novel approach to controlling WAT mass in obesity.


Assuntos
Gordura Abdominal/metabolismo , Adiposidade/genética , Síndrome de Costello/genética , Síndrome de Costello/metabolismo , Mitocôndrias/metabolismo , Proteínas/genética , Termogênese/genética , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Marrom/patologia , Animais , Síndrome de Costello/sangue , Modelos Animais de Doenças , Feminino , Genótipo , Metabolismo dos Lipídeos , Fígado/metabolismo , Fígado/patologia , Masculino , Camundongos , Camundongos Knockout , Fenótipo , Proteínas/metabolismo
10.
Biochemistry ; 52(47): 8465-79, 2013 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-24224811

RESUMO

Costello syndrome is linked to activating mutations of a residue in the p-loop or the NKCD/SAK motifs of Harvey Ras (HRas). More than 10 HRas mutants that induce Costello syndrome have been identified; G12S HRas is the most prevalent of these. However, certain HRas p-loop mutations also are linked to cancer formation that are exemplified with G12V HRas. Despite these relations, specific links between types of HRas mutations and diseases evade definition because some Costello syndrome HRas p-loop mutations, such as G12S HRas, also often cause cancer. This study established novel kinetic parameter-based equations that estimate the value of the cellular fractions of the GTP-bound active form of HRas mutant proteins. Such calculations differentiate between two basic kinetic mechanisms that populate the GTP-bound form of Ras in cells. (i) The increase in the level of GTP-bound Ras is caused by the HRas mutation-mediated perturbation of the intrinsic kinetic characteristics of Ras. This generates a broad spectrum of the population of the GTP-bound form of HRas that typically causes Costello syndrome. The upper end of this spectrum of HRas mutants, as exemplified by G12S HRas, can also cause cancer. (ii) The increase in the level of GTP-bound Ras occurs because the HRas mutations perturb the action of p120GAP on Ras. This causes production of a significantly high population of the only GTP-bound form of HRas linked merely to cancer formation. HRas mutant G12V belongs to this category.


Assuntos
Síndrome de Costello/enzimologia , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Sequência de Aminoácidos , Substituição de Aminoácidos , Animais , Sítios de Ligação , Biocatálise , Síndrome de Costello/genética , Síndrome de Costello/metabolismo , Ativação Enzimática , Guanosina Difosfato/metabolismo , Guanosina Trifosfato/metabolismo , Humanos , Hidrólise , Cinética , Camundongos , Dados de Sequência Molecular , Proteínas Mutantes/metabolismo , Células NIH 3T3 , Estrutura Secundária de Proteína , Proteínas Proto-Oncogênicas p21(ras)/química , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Recombinantes/metabolismo , Transdução de Sinais , Proteína p120 Ativadora de GTPase/genética , Proteína p120 Ativadora de GTPase/metabolismo , ras-GRF1/genética , ras-GRF1/metabolismo
11.
J Recept Signal Transduct Res ; 33(2): 124-8, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23528009

RESUMO

CONTEXT: Pathological upregulation of the RAS/MAPK pathway causes Costello, Noonan and cardio-facio-cutaneous (CFC) syndrome; however, little is known about PI3K/AKT signal transduction in these syndromes. Previously, we found a novel mutation of the SOS1 gene (T158A) in a patient with Costello/CFC overlapping phenotype. OBJECTIVE: The aim of this study was to investigate how this mutation affects RAS/MAPK as well as PI3K/AKT pathway signal transduction. MATERIALS AND METHODS: Wild-type and mutant (T158A) Son of Sevenless 1 (SOS1) were transfected into 293T cells. The levels of phospho- and total ERK1/2, AKT, p70S6K and pS6 were examined under epidermal growth factor (EGF) stimulation. RESULTS: After EGF stimulation, the ratio of phospho-ERK1/2 to total ERK1/2 was highest at 5 min in mutant (T158A) SOS1 cells, and at 15 min in wild-type SOS1 cells. Phospho-AKT was less abundant at 60 min in mutant than in wild-type SOS1 cells. Phosphorylation at various sites in p70S6K differed between wild-type and mutant cells. Eighteen hours after activation by EGF, the ratio of phospho-ERK1/2 to total ERK1/2 remained significantly higher in mutant than in wild-type SOS1 cells, but that of phospho-AKT to total AKT was unchanged. DISCUSSION: T158A is located in the histone-like domain, which may have a role in auto-inhibition of RAS exchanger activity of SOS1. T158A may disrupt auto-inhibition and enhance RAS signaling. T158A also affects PI3K/AKT signaling, probably via negative feedback via phospho-p70S6K. CONCLUSION: The SOS1 T158A mutation altered the phosphorylation of gene products involved in both RAS/MAPK and PI3K/AKT pathways.


Assuntos
Síndrome de Costello/genética , Fosfatidilinositol 3-Quinases/metabolismo , Proteína SOS1/genética , Proteínas ras/metabolismo , Síndrome de Costello/metabolismo , Síndrome de Costello/patologia , Células HEK293 , Humanos , Mutação , Proteína Oncogênica v-akt/genética , Proteína Oncogênica v-akt/metabolismo , Fosfatidilinositol 3-Quinases/genética , Fosforilação , Transdução de Sinais , Proteínas ras/genética
12.
Pediatr Dermatol ; 30(6): 665-73, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24283439

RESUMO

Costello syndrome (CS) and cardiofaciocutaneous syndrome (CFCS) are congenital disorders involving the Ras-MAPK pathway with phenotypic overlap. These two entities are thought to share common cutaneous findings, although so far they have been poorly studied. The objective of this prospective observational study was to describe the spectrum of skin findings in CS and CFCS and to highlight those specific to each of these two diseases. Patients with a confirmed diagnosis of CFCS or CS underwent a systematic skin examination during the annual workshop organized by the French CS association in 2007 and 2009 in Bordeaux, France. Eighteen patients were included in the study. Specific skin abnormalities, including cutis laxa, curly hair, pruritus, and hyperhidrosis, are shared by CFCS and CS, whereas others may help to differentiate between these two syndromes. Acanthosis nigricans, papillomas, and loose thick skin of the dorsum of the hands are characteristic of CS, whereas sparse eyebrows and dry hyperkeratotic skin are suggestive of CFCS. Our results highlight that a systematic cutaneous examination, in addition to dysmorphologic and noncutaneous anomalies, may be helpful in establishing the diagnosis of CFCS and CS. The physiopathologic link between constitutional Ras-MAPK pathway activation and the observed ectodermal findings remains to be investigated.


Assuntos
Síndrome de Costello/etiologia , Síndrome de Costello/patologia , Displasia Ectodérmica/etiologia , Displasia Ectodérmica/patologia , Insuficiência de Crescimento/etiologia , Insuficiência de Crescimento/patologia , Cardiopatias Congênitas/etiologia , Cardiopatias Congênitas/patologia , Pele/patologia , Criança , Pré-Escolar , Síndrome de Costello/metabolismo , Diagnóstico Diferencial , Displasia Ectodérmica/metabolismo , Fácies , Insuficiência de Crescimento/metabolismo , Feminino , Cardiopatias Congênitas/metabolismo , Humanos , Lactente , Sistema de Sinalização das MAP Quinases/fisiologia , Masculino , Pele/metabolismo , Adulto Jovem
13.
Hum Mol Genet ; 19(5): 790-802, 2010 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-19995790

RESUMO

Costello syndrome (CS) is a developmental disorder characterized by postnatal reduced growth, facial dysmorphism, cardiac defects, mental retardation and skin and musculo-skeletal defects. CS is caused by HRAS germline mutations. In the majority of cases, mutations affect Gly(12) and Gly(13) and are associated with a relatively homogeneous phenotype. The same amino acid substitutions are well known as somatic mutations in human tumors and promote constitutive HRAS activation by impairing its GTPase activity. In a small number of cases with mild phenotype, a second class of substitutions involving codons 117 and 146 and affecting GTP/GDP binding has been described. Here, we report on the identification and functional characterization of two different three-nucleotide duplications resulting in a duplication of glutamate 37 (p.E37dup) associated with a homogeneous phenotype reminiscent of CS. Ectopic expression of HRAS(E37dup) in COS-7 cells resulted in enhanced growth factor-dependent stimulation of the MEK-ERK and phosphoinositide 3-kinase (PI3K)-AKT signaling pathways. Recombinant HRAS(E37dup) was characterized by slightly increased GTP/GDP dissociation, lower intrinsic GTPase activity and complete resistance to neurofibromin 1 GTPase-activating protein (GAP) stimulation due to dramatically reduced binding. Co-precipitation of GTP-bound HRAS(E37dup) by various effector proteins, however, was inefficient because of drastically diminished binding affinities. Thus, although HRAS(E37dup) is predominantly present in the active, GTP-bound state, it promotes only a weak hyperactivation of downstream signaling pathways. These findings provide evidence that the mildly enhanced signal flux through the MAPK and PI3K-AKT cascades promoted by these disease-causing germline HRAS alleles results from a balancing effect between a profound GAP insensitivity and inefficient binding to effector proteins.


Assuntos
Síndrome de Costello/genética , Ácido Glutâmico/genética , Sistema de Sinalização das MAP Quinases/fisiologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética , Alelos , Animais , Células COS , Criança , Pré-Escolar , Chlorocebus aethiops , Síndrome de Costello/metabolismo , Síndrome de Costello/patologia , Fácies , Genes ras , Humanos , Mutação , Neurofibromina 1/metabolismo , Fenótipo , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Transdução de Sinais
14.
Muscle Nerve ; 46(3): 394-9, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22907230

RESUMO

INTRODUCTION: RASopathies are a group of genetic conditions due to alterations of the Ras/MAPK pathway. Neurocutaneous findings are hallmark features of the RASopathies, but musculoskeletal abnormalities are also frequent. The objective was to evaluate handgrip strength in the RASopathies. METHODS: Individuals with RASopathies (e.g., Noonan syndrome, Costello syndrome, cardio-facio-cutaneous [CFC] syndrome, and neurofibromatosis type 1 [NF1]) and healthy controls were evaluated. Two methods of handgrip strength were tested: GRIP-D Takei Hand Grip Dynamometer and the Martin vigorimeter. A general linear model was fitted to compare average strength among the groups, controlling for confounders such as age, gender, height, and weight. RESULTS: Takei dynamometer: handgrip strength was decreased in each of the syndromes compared with controls. Decreased handgrip strength compared with sibling controls was also seen with the Martin vigorimeter (P < 0.0001). CONCLUSIONS: Handgrip strength is decreased in the RASopathies. The etiology of the reduced muscle force is unknown, but likely multifactorial.


Assuntos
Síndrome de Costello/fisiopatologia , Displasia Ectodérmica/fisiopatologia , Insuficiência de Crescimento/fisiopatologia , Força da Mão/fisiologia , Cardiopatias Congênitas/fisiopatologia , Debilidade Muscular/fisiopatologia , Neurofibromatose 1/fisiopatologia , Síndrome de Noonan/fisiopatologia , Proteínas ras/genética , Adolescente , Adulto , Criança , Pré-Escolar , Síndrome de Costello/genética , Síndrome de Costello/metabolismo , Displasia Ectodérmica/genética , Displasia Ectodérmica/metabolismo , Fácies , Insuficiência de Crescimento/genética , Insuficiência de Crescimento/metabolismo , Feminino , Cardiopatias Congênitas/genética , Cardiopatias Congênitas/metabolismo , Humanos , Sistema de Sinalização das MAP Quinases/genética , Masculino , Pessoa de Meia-Idade , Debilidade Muscular/genética , Debilidade Muscular/metabolismo , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiopatologia , Neurofibromatose 1/genética , Neurofibromatose 1/metabolismo , Síndrome de Noonan/genética , Síndrome de Noonan/metabolismo , Proteínas ras/metabolismo
15.
J Clin Invest ; 132(8): 1-5, 2022 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-35426371

RESUMO

RASopathies are a family of rare autosomal dominant disorders that affect the canonical Ras/MAPK signaling pathway and manifest as neurodevelopmental systemic syndromes, including Costello syndrome (CS). In this issue of the JCI, Dard et al. describe the molecular determinants of CS using a myriad of genetically modified models, including mice expressing HRAS p.G12S, patient-derived skin fibroblasts, hiPSC-derived human cardiomyocytes, an HRAS p.G12V zebrafish model, and human lentivirally induced fibroblasts overexpressing HRAS p.G12S or HRAS p.G12A. Mitochondrial proteostasis and oxidative phosphorylation were altered in CS, and inhibition of the AMPK signaling pathway mediated bioenergetic changes. Importantly, the pharmacological induction of this pathway restored cardiac function and reduced the developmental defects associated with CS. These findings identify a role for altered bioenergetics and provide insights into more effective treatment strategies for patients with RASopathies.


Assuntos
Síndrome de Costello , Peixe-Zebra , Animais , Síndrome de Costello/metabolismo , Metabolismo Energético , Humanos , Camundongos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Transdução de Sinais , Peixe-Zebra/metabolismo
16.
J Clin Invest ; 132(8)2022 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-35230976

RESUMO

Germline mutations that activate genes in the canonical RAS/MAPK signaling pathway are responsible for rare human developmental disorders known as RASopathies. Here, we analyzed the molecular determinants of Costello syndrome (CS) using a mouse model expressing HRAS p.G12S, patient skin fibroblasts, hiPSC-derived human cardiomyocytes, a HRAS p.G12V zebrafish model, and human fibroblasts expressing lentiviral constructs carrying HRAS p.G12S or HRAS p.G12A mutations. The findings revealed alteration of mitochondrial proteostasis and defective oxidative phosphorylation in the heart and skeletal muscle of CS mice that were also found in the cell models of the disease. The underpinning mechanisms involved the inhibition of the AMPK signaling pathway by mutant forms of HRAS, leading to alteration of mitochondrial proteostasis and bioenergetics. Pharmacological activation of mitochondrial bioenergetics and quality control restored organelle function in HRAS p.G12A and p.G12S cell models, reduced left ventricle hypertrophy in CS mice, and diminished the occurrence of developmental defects in the CS zebrafish model. Collectively, these findings highlight the importance of mitochondrial proteostasis and bioenergetics in the pathophysiology of RASopathies and suggest that patients with CS may benefit from treatment with mitochondrial modulators.


Assuntos
Síndrome de Costello , Mutação em Linhagem Germinativa , Proteínas Proto-Oncogênicas p21(ras) , Proteínas Quinases Ativadas por AMP/genética , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Síndrome de Costello/genética , Síndrome de Costello/metabolismo , Homeostase , Humanos , Camundongos , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Peixe-Zebra/genética , Peixe-Zebra/metabolismo
17.
Dis Model Mech ; 15(2)2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-34553752

RESUMO

Costello syndrome (CS) is a congenital disorder caused by heterozygous activating germline HRAS mutations in the canonical Ras/mitogen-activated protein kinase (Ras/MAPK) pathway. CS is one of the RASopathies, a large group of syndromes caused by mutations within various components of the Ras/MAPK pathway. An important part of the phenotype that greatly impacts quality of life is hypotonia. To gain a better understanding of the mechanisms underlying hypotonia in CS, a mouse model with an activating HrasG12V allele was utilized. We identified a skeletal myopathy that was due, in part, to inhibition of embryonic myogenesis and myofiber formation, resulting in a reduction in myofiber size and number that led to reduced muscle mass and strength. In addition to hyperactivation of the Ras/MAPK and PI3K/AKT pathways, there was a significant reduction in p38 signaling, as well as global transcriptional alterations consistent with the myopathic phenotype. Inhibition of Ras/MAPK pathway signaling using a MEK inhibitor rescued the HrasG12V myopathy phenotype both in vitro and in vivo, demonstrating that increased MAPK signaling is the main cause of the muscle phenotype in CS.


Assuntos
Síndrome de Costello , Doenças Musculares , Animais , Síndrome de Costello/genética , Síndrome de Costello/metabolismo , Camundongos , Quinases de Proteína Quinase Ativadas por Mitógeno/genética , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Mutação/genética , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Qualidade de Vida
18.
J Biol Chem ; 285(51): 40282-93, 2010 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-20947500

RESUMO

The results of our in vitro experiments indicate that exposing cultured human aortic smooth muscle cells and dermal fibroblasts to 39 to 41 °C induces a significant up-regulation in the net deposition of elastic fibers, but not of collagen I or fibronectin, and also decreases the deposition of chondroitin sulfate-containing moieties. We further demonstrate that mild hyperthermia also rectifies the insufficient elastogenesis notable in cultures of fibroblasts derived from the stretch-marked skin of adult patients and in cultures of dermal fibroblasts from children with Costello syndrome, which is characterized by the accumulation of chondroitin 6-sulfate glycosaminoglycans that induce shedding and inactivation of the 67-kDa elastin-binding protein. We have previously established that this protein serves as a reusable chaperone for tropoelastin and that its recycling is essential for the normal deposition of elastic fibers. We now report that hyperthermia not only inhibits deposition of chondroitin 6-sulfate moieties and the consequent preservation of elastin-binding protein molecules but also induces their faster recycling. This, in turn, triggers a more efficient preservation of tropoelastin, enhancement of its secretion and extracellular assembly into elastic fibers. The presented results encourage using mild hyperthermia to restore elastic fiber production in damaged adult skin and to enhance elastogenesis in children with genetic elastinopathies.


Assuntos
Síndrome de Costello/metabolismo , Tecido Elástico/metabolismo , Fibroblastos/metabolismo , Resposta ao Choque Térmico , Receptores de Superfície Celular/metabolismo , Tropoelastina/metabolismo , Adulto , Células Cultivadas , Criança , Pré-Escolar , Síndrome de Costello/patologia , Tecido Elástico/patologia , Fibroblastos/patologia , Glicosaminoglicanos , Humanos , Lactente , Masculino
19.
Methods Mol Biol ; 2262: 397-409, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33977491

RESUMO

Costello syndrome (CS), characterized by a developmental delay and a failure to thrive, is also associated with an impaired lipid and energy metabolism. White adipose tissue is a central sensor of whole-body energy homeostasis, and HRAS hyperactivation may affect adipocyte differentiation and mature adipocyte homeostasis. An extremely useful tool for delineating in vitro intrinsic cellular signaling leading to metabolic alterations during adipogenesis is mouse embryonic fibroblasts, known to differentiate into adipocytes in response to adipogenesis-stimulating factors. Here, we describe in detail the isolation and maintenance of CS HRAS G12V mouse embryonic fibroblasts, their differentiation into adipocytes, and an assessment of adipocyte differentiation.


Assuntos
Adipócitos/patologia , Diferenciação Celular , Síndrome de Costello/patologia , Modelos Animais de Doenças , Fibroblastos/patologia , Mutação , Proteínas Proto-Oncogênicas p21(ras)/fisiologia , Adipócitos/metabolismo , Adipogenia , Animais , Síndrome de Costello/genética , Síndrome de Costello/metabolismo , Embrião de Mamíferos/metabolismo , Embrião de Mamíferos/patologia , Feminino , Fibroblastos/metabolismo , Homeostase , Técnicas In Vitro , Masculino , Camundongos , Camundongos Knockout
20.
Mech Ageing Dev ; 194: 111411, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33309600

RESUMO

Senescence is a biological process that induces a permanent cell cycle arrest and a specific gene expression program in response to various stressors. Following studies over the last few decades, the concept of senescence has evolved from an antiproliferative mechanism in cancer (oncogene-induced senescence) to a critical component of physiological processes associated with embryonic development, tissue regeneration, ageing and its associated diseases. In somatic cells, oncogenic mutations in RAS-MAPK pathway genes are associated with oncogene-induced senescence and cancer, while germline mutations in the same pathway are linked to a group of monogenic developmental disorders generally termed RASopathies. Here, we consider that in these disorders, senescence induction may result in opposing outcomes, a tumour protective effect and a possible contributor to a premature ageing phenotype identified in Costello syndrome, which belongs to the RASopathy group. In this review, we will highlight the role of senescence in organismal homeostasis and we will describe the current knowledge about senescence in RASopathies. Additionally, we provide a perspective on examples of experimentally characterised RASopathy mutations that, alone or in combination with various stressors, may also trigger an age-dependent chronic senescence, possibly contributing to the age-dependent worsening of RASopathy pathophenotype and the reduction of lifespan.


Assuntos
Senilidade Prematura/metabolismo , Envelhecimento/metabolismo , Proliferação de Células , Senescência Celular , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas ras/metabolismo , Fatores Etários , Envelhecimento/genética , Envelhecimento/patologia , Senilidade Prematura/genética , Senilidade Prematura/patologia , Animais , Diferenciação Celular , Síndrome de Costello/genética , Síndrome de Costello/metabolismo , Síndrome de Costello/patologia , Displasia Ectodérmica/genética , Displasia Ectodérmica/metabolismo , Displasia Ectodérmica/patologia , Fácies , Insuficiência de Crescimento/genética , Insuficiência de Crescimento/metabolismo , Insuficiência de Crescimento/patologia , Predisposição Genética para Doença , Cardiopatias Congênitas/genética , Cardiopatias Congênitas/metabolismo , Cardiopatias Congênitas/patologia , Humanos , Mutação , Síndrome de Noonan/genética , Síndrome de Noonan/metabolismo , Síndrome de Noonan/patologia , Fenótipo , Transdução de Sinais , Proteínas ras/genética
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