Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 23
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Cell Rep ; 31(2): 107495, 2020 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-32294447

RESUMO

Tbr1 is a high-confidence autism spectrum disorder (ASD) gene encoding a transcription factor with distinct pre- and postnatal functions. Postnatally, Tbr1 conditional knockout (CKO) mutants and constitutive heterozygotes have immature dendritic spines and reduced synaptic density. Tbr1 regulates expression of several genes that underlie synaptic defects, including a kinesin (Kif1a) and a WNT-signaling ligand (Wnt7b). Furthermore, Tbr1 mutant corticothalamic neurons have reduced thalamic axonal arborization. LiCl and a GSK3ß inhibitor, two WNT-signaling agonists, robustly rescue the dendritic spines and the synaptic and axonal defects, suggesting that this could have relevance for therapeutic approaches in some forms of ASD.


Assuntos
Espinhas Dendríticas/metabolismo , Proteínas com Domínio T/metabolismo , Via de Sinalização Wnt/fisiologia , Animais , Transtorno do Espectro Autista/genética , Proteínas de Ligação a DNA/metabolismo , Espinhas Dendríticas/fisiologia , Feminino , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neurogênese/fisiologia , Neurônios/metabolismo , Neurônios/fisiologia , Sinapses/metabolismo , Proteínas com Domínio T/genética , Proteínas com Domínio T/fisiologia , Tálamo/metabolismo , Via de Sinalização Wnt/genética
2.
Cereb Cortex ; 29(2): 505-516, 2019 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29293918

RESUMO

SEC14 and Spectrin domain-1 (Sestd1) is a synapse protein that exhibits a striking shift from the presynaptic to postsynaptic space as neurons mature postnatally in the mouse hippocampus. Hippocampal pyramidal neurons from mice with global genetic deletion of Sestd1 have reduced dendrite arbors, spines, and excitatory synapses. Electrophysiologically this correlates with cell-autonomous reductions in both AMPA- and NMDA-excitatory postsynaptic currents in individual hippocampal neurons from which Sestd1 has been deleted in vivo. These neurodevelopmental and functional deficits are associated with increased activation of the Rho family GTPases Rac1 and RhoA. Co-immunoprecipitation and mass spectrometry reveal that the Breakpoint Cluster Region protein, a Rho GTPase activating protein (GAP), forms complexes with Sestd1 in brain tissue. This complements earlier findings that Sestd1 can also partner with other Rho family GAPs and guanine nucleotide exchange factors. Our findings demonstrate that Sestd1 is a developmentally dynamic synaptic regulator of Rho GTPases that contributes to dendrite and excitatory synapse formation within differentiating pyramidal neurons of the forebrain.


Assuntos
Proteínas de Transporte/metabolismo , Espinhas Dendríticas/metabolismo , Neuropeptídeos/metabolismo , Prosencéfalo/metabolismo , Proteínas Proto-Oncogênicas c-bcr/metabolismo , Sinapses/metabolismo , Proteínas rac1 de Ligação ao GTP/metabolismo , Animais , Proteínas de Transporte/análise , Dendritos/química , Dendritos/metabolismo , Espinhas Dendríticas/química , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Neurogênese/fisiologia , Neuropeptídeos/análise , Técnicas de Cultura de Órgãos , Prosencéfalo/química , Prosencéfalo/crescimento & desenvolvimento , Proteínas Proto-Oncogênicas c-bcr/análise , Sinapses/química , Proteínas rac1 de Ligação ao GTP/análise
4.
Mol Neuropsychiatry ; 2(4): 219-246, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28277568

RESUMO

Mounting evidence indicates that Wnt signaling is relevant to pathophysiology of diverse mental illnesses including schizophrenia, bipolar disorder, and autism spectrum disorder. In the 35 years since Wnt ligands were first described, animal studies have richly explored how downstream Wnt signaling pathways affect an array of neurodevelopmental processes and how their disruption can lead to both neurological and behavioral phenotypes. Recently, human induced pluripotent stem cell (hiPSC) models have begun to contribute to this literature while pushing it in increasingly translational directions. Simultaneously, large-scale human genomic studies are providing evidence that sequence variation in Wnt signal pathway genes contributes to pathogenesis in several psychiatric disorders. This article reviews neurodevelopmental and postneurodevelopmental functions of Wnt signaling, highlighting mechanisms, whereby its disruption might contribute to psychiatric illness, and then reviews the most reliable recent genetic evidence supporting that mutations in Wnt pathway genes contribute to psychiatric illness. We are proponents of the notion that studies in animal and hiPSC models informed by the human genetic data combined with the deep knowledge base and tool kits generated over the last several decades of basic neurodevelopmental research will yield near-term tangible advances in neuropsychiatry.

5.
Clin J Gastroenterol ; 9(6): 375-378, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27699640

RESUMO

We report a case of irritable bowel syndrome (IBS), diarrhea subtype, characterized by daily 'morning rush' and episodic acute exacerbations brought on by common IBS trigger foods including insoluble fiber, red wine and large/rich meals. The patient also had a history of migraine headaches, and a family history suggesting a common diathesis for both disorders. Given hypothesized contributions to IBS from dysregulation of the enteric serotonergic system, a trial of low-dose triptan medication was implemented in the context of the patient's known IBS triggers, with highly satisfactory results.


Assuntos
Fármacos Gastrointestinais/administração & dosagem , Síndrome do Intestino Irritável/prevenção & controle , Triptaminas/administração & dosagem , Doença Aguda , Administração Oral , Diagnóstico Diferencial , Fármacos Gastrointestinais/uso terapêutico , Humanos , Síndrome do Intestino Irritável/diagnóstico , Masculino , Pessoa de Meia-Idade , Triptaminas/uso terapêutico
6.
Mol Neuropsychiatry ; 2(2): 107-14, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27606324

RESUMO

The transmembrane protein Vangl2, a key regulator of the Wnt/planar cell polarity (PCP) pathway, is involved in dendrite arbor elaboration, dendritic spine formation and glutamatergic synapse formation in mammalian central nervous system neurons. Cultured forebrain neurons from Vangl2 knockout mice have simpler dendrite arbors, fewer total spines, less mature spines and fewer glutamatergic synapse inputs on their dendrites than control neurons. Neurons from mice heterozygous for a semidominant Vangl2 mutation have similar but not identical phenotypes, and these phenotypes are also observed in Golgi-stained brain tissue from adult mutant mice. Given increasing evidence linking psychiatric pathophysiology to these subneuronal sites and structures, our findings underscore the relevance of core PCP proteins including Vangl2 to the underlying biology of major mental illnesses and their treatment.

7.
PLoS One ; 8(6): e67679, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23826333

RESUMO

Synaptogenesis has been extensively studied along with dendritic spine development in glutamatergic pyramidal neurons, however synapse development in cortical interneurons, which are largely aspiny, is comparatively less well understood. Dact1, one of 3 paralogous Dact (Dapper/Frodo) family members in mammals, is a scaffold protein implicated in both the Wnt/ß-catenin and the Wnt/Planar Cell Polarity pathways. We show here that Dact1 is expressed in immature cortical interneurons. Although Dact1 is first expressed in interneuron precursors during proliferative and migratory stages, constitutive Dact1 mutant mice have no major defects in numbers or migration of these neurons. However, cultured cortical interneurons derived from these mice have reduced numbers of excitatory synapses on their dendrites. We selectively eliminated Dact1 from mouse cortical interneurons using a conditional knock-out strategy with a Dlx-I12b enhancer-Cre allele, and thereby demonstrate a cell-autonomous role for Dact1 during postsynaptic development. Confirming this cell-autonomous role, we show that synapse numbers in Dact1 deficient cortical interneurons are rescued by virally-mediated re-expression of Dact1 specifically targeted to these cells. Synapse numbers in these neurons are also rescued by similarly targeted expression of the Dact1 binding partner Dishevelled-1, and partially rescued by expression of Disrupted in Schizophrenia-1, a synaptic protein genetically implicated in susceptibility to several major mental illnesses. In sum, our results support a novel cell-autonomous postsynaptic role for Dact1, in cooperation with Dishevelled-1 and possibly Disrupted in Schizophrenia-1, in the formation of synapses on cortical interneuron dendrites.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Neurônios GABAérgicos/metabolismo , Interneurônios/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Fosfoproteínas/metabolismo , Prosencéfalo/citologia , Prosencéfalo/crescimento & desenvolvimento , Animais , Movimento Celular , Dendritos/metabolismo , Proteínas Desgrenhadas , Neurônios GABAérgicos/citologia , Regulação da Expressão Gênica no Desenvolvimento , Interneurônios/citologia , Peptídeos e Proteínas de Sinalização Intracelular/genética , Lentivirus/metabolismo , Camundongos , Camundongos Knockout , Camundongos Mutantes , Proteínas do Tecido Nervoso/metabolismo , Inibição Neural , Prosencéfalo/metabolismo , Ligação Proteica , Proteínas de Ligação a RNA , Sinapses/metabolismo
8.
J Biol Chem ; 288(28): 20111-20, 2013 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-23696638

RESUMO

The planar cell polarity (PCP) pathway is a conserved non-canonical (ß-catenin-independent) branch of Wnt signaling crucial to embryogenesis, during which it regulates cell polarity and polarized cell movements. Disruption of PCP components in mice, including Vangl2 and Dact1, results in defective neural tube closure and other developmental defects. Here, we show that Sestd1 is a novel binding partner of Vangl2 and Dact1. The Sestd1-Dact1 interface is formed by circumscribed regions of Sestd1 (the carboxyl-terminal region) and Dact1 (the amino-terminal region). Remarkably, we show that loss of Sestd1 precisely phenocopies loss of Dact1 during embryogenesis in mice, leading to a spectrum of birth malformations, including neural tube defects, a shortened and/or curly tail, no genital tubercle, blind-ended colons, hydronephrotic kidneys, and no bladder. Moreover, as with Dact1, a knock-out mutation at the Sestd1 locus exhibits reciprocal genetic rescue interactions during development with a semidominant mutation at the Vangl2 locus. Consistent with this, examination of Wnt pathway activities in Sestd1 mutant mouse embryonic tissue reveals disrupted PCP pathway biochemistry similar to that characterized in Dact1 mutant embryos. The Sestd1 protein is a divergent member of the Trio family of GTPase regulatory proteins that lacks a guanine nucleotide exchange factor domain. Nonetheless, in cell-based assays the Sestd1-Dact1 interaction can induce Rho GTPase activation. Together, our data indicate that Sestd1 cooperates with Dact1 in Vangl2 regulation and in the PCP pathway during mammalian embryonic development.


Assuntos
Proteínas de Transporte/metabolismo , Polaridade Celular , Desenvolvimento Embrionário , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Animais , Proteínas de Transporte/genética , Células Cultivadas , Embrião de Mamíferos/citologia , Embrião de Mamíferos/embriologia , Embrião de Mamíferos/metabolismo , Ativação Enzimática , Fibroblastos/citologia , Fibroblastos/metabolismo , Células HEK293 , Humanos , Immunoblotting , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mutação , Proteínas do Tecido Nervoso/genética , Ligação Proteica , Proteínas de Ligação a RNA , Transdução de Sinais/genética , Via de Sinalização Wnt/genética , Proteínas rho de Ligação ao GTP/metabolismo
9.
J Neuroimmune Pharmacol ; 7(4): 774-87, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23015196

RESUMO

Members of the Wnt family of secreted signaling proteins influence many aspects of neural development and function. Wnts are required from neural induction and axis formation to axon guidance and synapse development, and even help modulate synapse activity. Wnt proteins activate a variety of downstream signaling pathways and can induce a similar variety of cellular responses, including gene transcription changes and cytoskeletal rearrangements. This review provides an introduction to Wnt signaling pathways and discusses current research on their roles in vertebrate neural development and function.


Assuntos
Sistema Nervoso/crescimento & desenvolvimento , Vertebrados/fisiologia , Via de Sinalização Wnt/fisiologia , Animais , Axônios/fisiologia , Encéfalo/crescimento & desenvolvimento , Encéfalo/fisiologia , Movimento Celular/fisiologia , Dendritos/fisiologia , Humanos , Fenômenos Fisiológicos do Sistema Nervoso , Neurogênese/fisiologia , Sinapses/fisiologia
10.
BMC Biochem ; 12: 33, 2011 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-21718540

RESUMO

BACKGROUND: The Dact family of scaffold proteins was discovered by virtue of binding to Dvl proteins central to Wnt and Planar Cell Polarity (PCP) signaling. Subsequently Dact proteins have been linked to a growing list of potential partners implicated in ß-catenin-dependent and ß-catenin-independent forms of Wnt and other signaling. To clarify conserved and non-conserved roles for this protein family, we systematically compared molecular interactions of all three murine Dact paralogs by co-immunoprecipitation of proteins recombinantly expressed in cultured human embryonic kidney cells. RESULTS: Every Dact paralog readily formed complexes with the Vangl, Dvl, and CK1δ/ε proteins of species ranging from fruit flies to humans, as well as with PKA and PKC. Dact proteins also formed complexes with themselves and with each other; their conserved N-terminal leucine-zipper domains, which have no known binding partners, were necessary and sufficient for this interaction, suggesting that it reflects leucine-zipper-mediated homo- and hetero-dimerization. We also found weaker, though conserved, interactions of all three Dact paralogs with the catenin superfamily member p120ctn. Complex formation with other previously proposed partners including most other catenins, GSK3, LEF/TCF, HDAC1, and TGFß receptors was paralog-specific, comparatively weak, and/or more sensitive to empirical conditions. CONCLUSIONS: Combined with published functional evidence from targeted knock-out mice, these data support a conserved role for Dact proteins in kinase-regulated biochemistry involving Vangl and Dvl. This strongly suggests that a principal role for all Dact family members is in the PCP pathway or a molecularly related signaling cascade in vertebrates.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Proteínas de Transporte/metabolismo , Caseína Quinase 1 épsilon/metabolismo , Caseína Quinase Idelta/metabolismo , Cateninas/metabolismo , Linhagem Celular , Dimerização , Proteínas Desgrenhadas , Eletroforese em Gel de Poliacrilamida , Quinase 3 da Glicogênio Sintase/metabolismo , Fator 1-alfa Nuclear de Hepatócito/metabolismo , Histona Desacetilase 1/metabolismo , Humanos , Imunoprecipitação , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas de Membrana/metabolismo , Camundongos , Peso Molecular , Proteínas do Tecido Nervoso/metabolismo , Fosfoproteínas/química , Fosfoproteínas/metabolismo , Mapas de Interação de Proteínas , Proteínas de Ligação a RNA , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Fator 1 de Transcrição de Linfócitos T/metabolismo , delta Catenina
11.
J Neurodev Disord ; 3(2): 162-74, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21533542

RESUMO

Wnt signaling is a key pathway that helps organize development of the nervous system. It influences cell proliferation, cell fate, and cell migration in the developing nervous system, as well as axon guidance, dendrite development, and synapse formation. Given this wide range of roles, dysregulation of Wnt signaling could have any number of deleterious effects on neural development and thereby contribute in many different ways to the pathogenesis of neurodevelopmental disorders. Some major psychiatric disorders, including schizophrenia, bipolar disorder, and autism spectrum disorders, are coming to be understood as subtle dysregulations of nervous system development, particularly of synapse formation and maintenance. This review will therefore touch on the importance of Wnt signaling to neurodevelopment generally, while focusing on accumulating evidence for a synaptic role of Wnt signaling. These observations will be discussed in the context of current understanding of the neurodevelopmental bases of major psychiatric diseases, spotlighting schizophrenia, bipolar disorder, and autism spectrum disorder. In short, this review will focus on the potential role of synapse formation and maintenance in major psychiatric disorders and summarize evidence that defective Wnt signaling could contribute to their pathogenesis via effects on these late neural differentiation processes.

12.
J Neurosci ; 30(12): 4362-8, 2010 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-20335472

RESUMO

Dact1 (Dapper/Frodo), an intracellular phosphoprotein that binds Dishevelled, catenins, and other signaling proteins, is expressed in the developing and mature mammalian CNS, but its function there is unknown. Dact1 colocalized with synaptic markers and partitioned to postsynaptic fractions from cultured mouse forebrain neurons. Hippocampal neurons from Dact1 knock-out mice had simpler dendritic arbors and fewer spines than hippocampal neurons from wild-type littermates. This correlated with reductions in excitatory synapses and miniature EPSCs, whereas inhibitory synapses were not affected. Loss of Dact1 resulted in a decrease in activated Rac, and recombinant expression of either Dact1 or constitutively active Rac, but not Rho or Cdc42, rescued dendrite and spine phenotypes in Dact1 mutant neurons. Our findings suggest that, during neuronal differentiation, Dact1 plays a critical role in a molecular pathway promoting Rac activity underlying the elaboration of dendrites and the establishment of spines and excitatory synapses.


Assuntos
Espinhas Dendríticas/fisiologia , Hipocampo/citologia , Hipocampo/crescimento & desenvolvimento , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Neurônios/citologia , Sinapses/fisiologia , Fatores Etários , Análise de Variância , Animais , Animais Recém-Nascidos , Células Cultivadas , Espinhas Dendríticas/ultraestrutura , Proteína 4 Homóloga a Disks-Large , Potenciais Pós-Sinápticos Excitadores/genética , Proteínas da Membrana Plasmática de Transporte de GABA/metabolismo , Proteínas de Fluorescência Verde/genética , Guanilato Quinases , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Knockout , Proteínas de Ligação a RNA , Coloração pela Prata/métodos , Frações Subcelulares/metabolismo , Proteína Vesicular 1 de Transporte de Glutamato/metabolismo , Proteínas rac de Ligação ao GTP/metabolismo
13.
Gene Expr Patterns ; 10(2-3): 140-3, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20170752

RESUMO

Wnt signaling is essential for tooth formation and Dact proteins modulate Wnt signaling by binding to the intracellular protein Dishevelled (Dvl). Comparison of the three known mouse Dact genes, Dact1-3, from the morphological initiation of mandibular first molar development through the onset of root formation using section in situ hybridization showed distinct, complementary and overlapping expression patterns for these genes. Whereas Dact2 expression was restricted to the dental epithelium, including the enamel knot signaling centers and pre-ameloblasts, Dact1 and Dact3 showed developmentally regulated expression in the dental mesenchyme. Both Dact1 and Dact3 mRNAs were first detected in the presumptive dental mesenchyme. After being downregulated from the condensing dental mesenchyme of the bud stage tooth germ, Dact1 was upregulated in the dental follicle mesenchyme at the cap stage and subsequently also in the dental papilla at the bell stage, where the expression persisted to the postnatal stages. In contrast, Dact3 transcripts persisted throughout the dental mesenchyme, including the preodontoblasts, during embryogenesis before transcripts were largely downregulated from the tooth germ postnatally. Collectively, these results suggest that Dact1 and -3 may contribute to early tooth formation by modulation of Wnt signaling pathways in the mesenchyme, including preodontoblasts, whereas Dact2 may play important signal-modulating roles in the adjacent epithelial cells including the enamel knot signaling centers and pre-ameloblasts. Future loss-of-function studies will help elucidate whether any of these functions are redundant, particularly for Dact1 and Dact3.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Mesoderma/metabolismo , Odontogênese/genética , Proteínas Adaptadoras de Transdução de Sinal/biossíntese , Animais , Epitélio/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Camundongos , Dente Molar/metabolismo , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA , Germe de Dente/metabolismo , Proteínas Wnt/fisiologia
14.
Nat Genet ; 41(9): 977-85, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19701191

RESUMO

Mice homozygous for mutations in Dact1 (also called Dapper or Frodo) phenocopy human malformations involving the spine, genitourinary system and distal digestive tract. We traced this phenotype to disrupted germ-layer morphogenesis at the primitive streak. Notably, heterozygous mutation of Vangl2, a transmembrane component of the planar cell polarity (PCP) pathway, rescued recessive Dact1 phenotypes, whereas loss of Dact1 reciprocally rescued semidominant Vangl2 phenotypes. We show that Dact1, an intracellular protein, forms a complex with Vangl2. In Dact1 mutants, Vangl2 was increased at the primitive streak, where cells ordinarily undergo an epithelial-mesenchymal transition. This is associated with abnormal E-cadherin distribution and changes in biochemical measures of the PCP pathway. We conclude that Dact1 contributes to morphogenesis at the primitive streak by regulating Vangl2 upstream of cell adhesion and the PCP pathway.


Assuntos
Anormalidades Congênitas/etiologia , Regulação da Expressão Gênica no Desenvolvimento , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Proteínas do Tecido Nervoso/metabolismo , Alelos , Sequência de Aminoácidos , Animais , Anormalidades Congênitas/genética , Sequência Conservada , Cruzamentos Genéticos , Homozigoto , Peptídeos e Proteínas de Sinalização Intracelular/química , Peptídeos e Proteínas de Sinalização Intracelular/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Dados de Sequência Molecular , Mutação , Proteínas do Tecido Nervoso/análise , Proteínas do Tecido Nervoso/genética , Linha Primitiva , Estrutura Terciária de Proteína , Proteínas de Ligação a RNA
15.
PLoS One ; 4(2): e4310, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19183803

RESUMO

BACKGROUND: Wnts are evolutionarily conserved ligands that signal through beta-catenin-dependent and beta-catenin-independent pathways to regulate cell fate, proliferation, polarity, and movements during vertebrate development. Dishevelled (Dsh/Dvl) is a multi-domain scaffold protein required for virtually all known Wnt signaling activities, raising interest in the identification and functions of Dsh-associated proteins. METHODOLOGY: We conducted a yeast-2-hybrid screen using an N-terminal fragment of Dsh, resulting in isolation of the Xenopus laevis ortholog of Hipk1. Interaction between the Dsh and Hipk1 proteins was confirmed by co-immunoprecipitation assays and mass spectrometry, and further experiments suggest that Hipk1 also complexes with the transcription factor Tcf3. Supporting a nuclear function during X. laevis development, Myc-tagged Hipk1 localizes primarily to the nucleus in animal cap explants, and the endogenous transcript is strongly expressed during gastrula and neurula stages. Experimental manipulations of Hipk1 levels indicate that Hipk1 can repress Wnt/beta-catenin target gene activation, as demonstrated by beta-catenin reporter assays in human embryonic kidney cells and by indicators of dorsal specification in X. laevis embryos at the late blastula stage. In addition, a subset of Wnt-responsive genes subsequently requires Hipk1 for activation in the involuting mesoderm during gastrulation. Moreover, either over-expression or knock-down of Hipk1 leads to perturbed convergent extension cell movements involved in both gastrulation and neural tube closure. CONCLUSIONS: These results suggest that Hipk1 contributes in a complex fashion to Dsh-dependent signaling activities during early vertebrate development. This includes regulating the transcription of Wnt/beta-catenin target genes in the nucleus, possibly in both repressive and activating ways under changing developmental contexts. This regulation is required to modulate gene expression and cell movements that are essential for gastrulation.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Fosfoproteínas/metabolismo , Proteínas Repressoras/metabolismo , Transdução de Sinais , Proteínas de Xenopus/metabolismo , beta Catenina/metabolismo , Sequência de Aminoácidos , Animais , Proteínas Desgrenhadas , Embrião não Mamífero/metabolismo , Gastrulação , Dados de Sequência Molecular , Fenótipo , Filogenia , Proteínas Serina-Treonina Quinases , Proteínas Repressoras/genética , Alinhamento de Sequência , Proteínas Wnt/genética , Proteínas Wnt/metabolismo , Proteínas de Xenopus/genética , Xenopus laevis/embriologia
16.
Diabetes ; 58(3): 609-19, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19073771

RESUMO

OBJECTIVE: Wnt signaling inhibits adipogenesis, but its regulation, physiological relevance, and molecular effectors are poorly understood. Here, we identify the Wnt modulator Dapper1/Frodo1 (Dact1) as a new preadipocyte gene involved in the regulation of murine and human adipogenesis. RESEARCH DESIGN AND METHODS: Changes in Dact1 expression were investigated in three in vitro models of adipogenesis. In vitro gain- and loss-of-function studies were used to investigate the mechanism of Dact1 action during adipogenesis. The in vivo regulation of Dact1 and Wnt/beta-catenin signaling were investigated in murine models of altered nutritional status, of pharmacological stimulation of in vivo adipogenesis, and during the development of dietary and genetic obesity. RESULTS: Dact1 is a preadipocyte gene that decreases during adipogenesis. However, Dact1 knockdown impairs adipogenesis through activation of the Wnt/beta-catenin signaling pathway, and this is reversed by treatment with the secreted Wnt antagonist, secreted Frizzled-related protein 1 (Sfrp1). In contrast, constitutive Dact1 overexpression promotes adipogenesis and confers resistance to Wnt ligand-induced antiadipogenesis through increased expression of endogenous Sfrps and reduced expression of Wnts. In vivo, in white adipose tissue, Dact1 and Wnt/beta-catenin signaling also exhibit coordinated expression profiles in response to altered nutritional status, in response to pharmacological stimulation of in vivo adipogenesis, and during the development of dietary and genetic obesity. CONCLUSIONS: Dact1 regulates adipogenesis through coordinated effects on gene expression that selectively alter intracellular and paracrine/autocrine components of the Wnt/beta-catenin signaling pathway. These novel insights into the molecular mechanisms controlling adipose tissue plasticity provide a functional network with therapeutic potential against diseases, such as obesity and associated metabolic disorders.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Adipócitos/fisiologia , Regulação da Expressão Gênica , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas Nucleares/genética , Proteínas Wnt/fisiologia , beta Catenina/fisiologia , Células 3T3-L1 , Adipócitos/citologia , Tecido Adiposo/fisiologia , Animais , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos , Diferenciação Celular , Genes Reporter , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Proteínas do Tecido Nervoso/genética , Análise de Sequência com Séries de Oligonucleotídeos , RNA Mensageiro/genética , Proteínas de Ligação a RNA , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Transcrição TCF/genética , Fator de Transcrição 4
17.
Cancer Cell ; 13(6): 529-41, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18538736

RESUMO

Genetic and epigenetic defects in Wnt/beta-catenin signaling play important roles in colorectal cancer progression. Here we identify DACT3, a member of the DACT (Dpr/Frodo) gene family, as a negative regulator of Wnt/beta-catenin signaling that is transcriptionally repressed in colorectal cancer. Unlike other Wnt signaling inhibitors that are silenced by DNA methylation, DACT3 repression is associated with bivalent histone modifications. Remarkably, DACT3 expression can be robustly derepressed by a pharmacological combination that simultaneously targets both histone methylation and deacetylation, leading to strong inhibition of Dishevelled (Dvl)-mediated Wnt/beta-catenin signaling and massive apoptosis of colorectal cancer cells. Our study identifies DACT3 as an important regulator of Wnt/beta-catenin signaling in colorectal cancer and suggests a potential strategy for therapeutic control of Wnt/beta-catenin signaling in colorectal cancer.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Neoplasias Colorretais/metabolismo , Epigênese Genética , Regulação Neoplásica da Expressão Gênica , Histonas/metabolismo , Transdução de Sinais/genética , Proteínas Wnt/metabolismo , beta Catenina/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Adenosina/análogos & derivados , Adenosina/farmacologia , Adenosil-Homocisteinase/antagonistas & inibidores , Adenosil-Homocisteinase/metabolismo , Apoptose , Azacitidina/análogos & derivados , Azacitidina/farmacologia , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/enzimologia , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Metilação de DNA , Metilases de Modificação do DNA/antagonistas & inibidores , Metilases de Modificação do DNA/metabolismo , Decitabina , Proteínas Desgrenhadas , Regulação para Baixo , Inibidores Enzimáticos/farmacologia , Epigênese Genética/efeitos dos fármacos , Perfilação da Expressão Gênica/métodos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Células HCT116 , Inibidores de Histona Desacetilases , Histona Desacetilases/metabolismo , Humanos , Ácidos Hidroxâmicos/farmacologia , Análise de Sequência com Séries de Oligonucleotídeos , Fosfoproteínas/metabolismo , Regiões Promotoras Genéticas , Reprodutibilidade dos Testes , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/efeitos dos fármacos , Transfecção , Proteínas Wnt/genética , beta Catenina/genética
18.
Pediatr Neurol ; 38(4): 273-5, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18358407

RESUMO

Dopa-responsive dystonia is a hereditary disease characterized by inadequate dopamine production. Autosomal-dominant cases result from mutations in the GCH1 gene, encoding guanosine triphosphate (GTP)-cyclohydrolase 1. The most common presenting manifestation is dystonia of a lower extremity, often worsening late in the day. The onset and clinical severity are variable, sometimes even within a single family. Gender effects on allele penetrance have been reported. We present a male toddler with dopa-responsive dystonia caused by an autosomal-dominant GCH1 mutation. Three other family members were also found to carry the mutation, with widely different functional consequences.


Assuntos
Carbidopa/uso terapêutico , Agonistas de Dopamina/uso terapêutico , Distúrbios Distônicos/tratamento farmacológico , Distúrbios Distônicos/genética , GTP Cicloidrolase/genética , Levodopa/uso terapêutico , Mutação/genética , Pré-Escolar , Combinação de Medicamentos , Distúrbios Distônicos/diagnóstico , Transtornos Neurológicos da Marcha/tratamento farmacológico , Transtornos Neurológicos da Marcha/etiologia , Humanos , Masculino , Linhagem
19.
Dev Dyn ; 235(11): 3177-83, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17013874

RESUMO

During segmentation (somitogenesis) in vertebrate embryos, somites form in a rostral-to-caudal sequence according to a species-specific rhythm called the somitogenesis clock. The expression of genes participating in somitogenesis oscillates in the presomitic mesoderm (PSM) in time with this clock. We previously reported that the Dact1 gene (aka Dpr1/Frd1/ThyEx3), which encodes a Dishevelled-binding intracellular regulator of Wnt signaling, is prominently expressed in the PSM as well as in a caudal-rostral gradient across the somites of mouse embryos. This observation led us to examine whether Dact1 expression oscillates in the PSM. We have found that Dact1 PSM expression does indeed oscillate in time with the somitogenesis clock. Consistent with its known signaling functions and with the "clock and wavefront" model of signal regulation during somitogenesis, the oscillation of Dact1 occurs in phase with the Wnt signaling component Axin2, and out of phase with the Notch signaling component Lfng.


Assuntos
Relógios Biológicos , Proteínas do Citoesqueleto/metabolismo , Desenvolvimento Embrionário , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Somitos/metabolismo , Animais , Proteína Axina , Padronização Corporal/genética , Proteínas do Citoesqueleto/análise , Proteínas do Citoesqueleto/genética , Desenvolvimento Embrionário/genética , Expressão Gênica , Glicosiltransferases/análise , Glicosiltransferases/genética , Glicosiltransferases/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/análise , Peptídeos e Proteínas de Sinalização Intracelular/genética , Mesoderma/química , Mesoderma/citologia , Mesoderma/metabolismo , Camundongos , Proteínas de Ligação a RNA , Somitos/química , Somitos/citologia
20.
Dev Dyn ; 235(9): 2620-30, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16881060

RESUMO

Members of the Dact protein family initially were identified through binding to Dishevelled (Dvl), a cytoplasmic protein central to Wnt signaling. During mouse development, Dact1 is detected in the presomitic mesoderm and somites during segmentation, in the limb bud mesenchyme and other mesoderm-derived tissues, and in the central nervous system (CNS). Dact2 expression is most prominent during organogenesis of the thymus, kidneys, and salivary glands, with much lower levels in the somites and in the developing CNS. Dact3, not previously described in any organism, is expressed in the ventral region of maturing somites, limb bud and branchial arch mesenchyme, and in the embryonic CNS; of the three paralogs, it is the most highly expressed in the adult cerebral cortex. These data are consistent with studies in other vertebrates showing that Dact paralogs have distinct signaling and developmental roles and suggest they may differentially contribute to postnatal brain physiology.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Encéfalo/crescimento & desenvolvimento , Encéfalo/metabolismo , Desenvolvimento Embrionário/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Família Multigênica , Sequência de Aminoácidos , Animais , Sequência de Bases , Sistema Nervoso Central/embriologia , Sistema Nervoso Central/metabolismo , Clonagem Molecular , Primers do DNA/genética , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Hibridização In Situ , Camundongos , Dados de Sequência Molecular , Filogenia , Gravidez , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA , Homologia de Sequência de Aminoácidos , Distribuição Tecidual
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...