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1.
Neurosci Lett ; 704: 116-125, 2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-30953735

RESUMO

In multiple sclerosis (MS) regeneration of oligodendrocytes following inflammatory demyelination is limited by the compromised ability of progenitors to repopulate lesioned areas and transition to functionally competent oligodendrocytes. Regarding underlying mechanisms, the involvement of epigenetic processes has been suggested, e.g. the contribution of histone deacetylases (HDAC) known to regulate oligodendrocyte progenitor cell (OPC) differentiation. However, their precise expression patterns, particular of redox-sensitive NAD+ HDACs, remains largely unknown. In this study, we determined the expression and activity of sirtuins, members of the HDAC class III family with a specific focus on SIRT1, previously associated with neurodegenerative, inflammatory and demyelinating disorders of the central nervous system (CNS). By investigating mouse experimental autoimmune encephalomyelitis (EAE), a model for MS, we found that transcription of SIRT1, SIRT2 and SIRT6 was significantly increased in the CNS during chronic disease stages. We confirmed this finding for SIRT1 protein expression and were able to localize upregulated SIRT1 in nuclei of NG2+ or PDGFRα+ OPCs in demyelinated brain lesions. In cultured mouse A2B5+ OPCs blockade of SIRT1 activity by the small molecule compound Ex527 enhanced mitotic activity but did not affect the capacity to differentiate. A similar pattern was detectable in OPCs derived from SIRT1-deficient animals. Taken together, our data suggest that SIRT1 inhibition may help to expand the endogenous pool of OPCs without affecting their differentiation.

2.
J Clin Invest ; 128(11): 5056-5072, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30320600

RESUMO

Dysregulated intestinal epithelial apoptosis initiates gut injury, alters the intestinal barrier, and can facilitate bacterial translocation leading to a systemic inflammatory response syndrome (SIRS) and/or multi-organ dysfunction syndrome (MODS). A variety of gastrointestinal disorders, including inflammatory bowel disease, have been linked to intestinal apoptosis. Similarly, intestinal hyperpermeability and gut failure occur in critically ill patients, putting the gut at the center of SIRS pathology. Regulation of apoptosis and immune-modulatory functions have been ascribed to Thirty-eight-negative kinase 1 (TNK1), whose activity is regulated merely by expression. We investigated the effect of TNK1 on intestinal integrity and its role in MODS. TNK1 expression induced crypt-specific apoptosis, leading to bacterial translocation, subsequent septic shock, and early death. Mechanistically, TNK1 expression in vivo resulted in STAT3 phosphorylation, nuclear translocation of p65, and release of IL-6 and TNF-α. A TNF-α neutralizing antibody partially blocked development of intestinal damage. Conversely, gut-specific deletion of TNK1 protected the intestinal mucosa from experimental colitis and prevented cytokine release in the gut. Finally, TNK1 was found to be deregulated in the gut in murine and porcine trauma models and human inflammatory bowel disease. Thus, TNK1 might be a target during MODS to prevent damage in several organs, notably the gut.

3.
Glia ; 2018 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-30256452

RESUMO

We and others previously showed that in mouse embryos lacking the transcription factor Sox10, olfactory ensheathing cell (OEC) differentiation is disrupted, resulting in defective olfactory axon targeting and fewer gonadotropin-releasing hormone (GnRH) neurons entering the embryonic forebrain. The underlying mechanisms are unclear. Here, we report that OECs in the olfactory nerve layer express Frzb-encoding a secreted Wnt inhibitor with roles in axon targeting and basement membrane breakdown-from embryonic day (E)12.5, when GnRH neurons first enter the forebrain, until E16.5, the latest stage examined. The highest levels of Frzb expression are seen in OECs in the inner olfactory nerve layer, abutting the embryonic olfactory bulb. We find that Sox10 is required for Frzb expression in OECs, suggesting that loss of Frzb could explain the olfactory axon targeting and/or GnRH neuron migration defects seen in Sox10-null mice. At E16.5, Frzb-null embryos show significant reductions in both the volume of the olfactory nerve layer expressing the maturation marker Omp and the number of Omp-positive olfactory receptor neurons in the olfactory epithelium. As Omp upregulation correlates with synapse formation, this suggests that Frzb deletion indeed disrupts olfactory axon targeting. In contrast, GnRH neuron entry into the forebrain is not significantly affected. Hence, loss of Frzb may contribute to the olfactory axon targeting phenotype, but not the GnRH neuron phenotype, of Sox10-null mice. Overall, our results suggest that Frzb secreted from OECs in the olfactory nerve layer is important for olfactory axon targeting.

4.
Brain ; 2018 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-29985992

RESUMO

The transcription factor BCL11B is essential for development of the nervous and the immune system, and Bcl11b deficiency results in structural brain defects, reduced learning capacity, and impaired immune cell development in mice. However, the precise role of BCL11B in humans is largely unexplored, except for a single patient with a BCL11B missense mutation, affected by multisystem anomalies and profound immune deficiency. Using massively parallel sequencing we identified 13 patients bearing heterozygous germline alterations in BCL11B. Notably, all of them are affected by global developmental delay with speech impairment and intellectual disability; however, none displayed overt clinical signs of immune deficiency. Six frameshift mutations, two nonsense mutations, one missense mutation, and two chromosomal rearrangements resulting in diminished BCL11B expression, arose de novo. A further frameshift mutation was transmitted from a similarly affected mother. Interestingly, the most severely affected patient harbours a missense mutation within a zinc-finger domain of BCL11B, probably affecting the DNA-binding structural interface, similar to the recently published patient. Furthermore, the most C-terminally located premature termination codon mutation fails to rescue the progenitor cell proliferation defect in hippocampal slice cultures from Bcl11b-deficient mice. Concerning the role of BCL11B in the immune system, extensive immune phenotyping of our patients revealed alterations in the T cell compartment and lack of peripheral type 2 innate lymphoid cells (ILC2s), consistent with the findings described in Bcl11b-deficient mice. Unsupervised analysis of 102 T lymphocyte subpopulations showed that the patients clearly cluster apart from healthy children, further supporting the common aetiology of the disorder. Taken together, we show here that mutations leading either to BCL11B haploinsufficiency or to a truncated BCL11B protein clinically cause a non-syndromic neurodevelopmental delay. In addition, we suggest that missense mutations affecting specific sites within zinc-finger domains might result in distinct and more severe clinical outcomes.

5.
Front Mol Neurosci ; 11: 103, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29674952

RESUMO

Structural and functional plasticity of synapses are critical neuronal mechanisms underlying learning and memory. While activity-dependent regulation of synaptic strength has been extensively studied, much less is known about the transcriptional control of synapse maintenance and plasticity. Hippocampal mossy fiber (MF) synapses connect dentate granule cells to CA3 pyramidal neurons and are important for spatial memory formation and consolidation. The transcription factor Bcl11b/Ctip2 is expressed in dentate granule cells and required for postnatal hippocampal development. Ablation of Bcl11b/Ctip2 in the adult hippocampus results in impaired adult neurogenesis and spatial memory. The molecular mechanisms underlying the behavioral impairment remained unclear. Here we show that selective deletion of Bcl11b/Ctip2 in the adult mouse hippocampus leads to a rapid loss of excitatory synapses in CA3 as well as reduced ultrastructural complexity of remaining mossy fiber boutons (MFBs). Moreover, a dramatic decline of long-term potentiation (LTP) of the dentate gyrus-CA3 (DG-CA3) projection is caused by adult loss of Bcl11b/Ctip2. Differential transcriptomics revealed the deregulation of genes associated with synaptic transmission in mutants. Together, our data suggest Bcl11b/Ctip2 to regulate maintenance and function of MF synapses in the adult hippocampus.

6.
J Vis Exp ; (125)2017 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-28784978

RESUMO

In utero electroporation is a rapid and powerful approach to study the process of radial migration in the cerebral cortex of developing mouse embryos. It has helped to describe the different steps of radial migration and characterize the molecular mechanisms controlling this process. To directly and dynamically analyze migrating neurons they have to be traced over time. This protocol describes a workflow that combines in utero electroporation with organotypic slice culture and time-lapse confocal imaging, which allows for a direct examination and dynamic analysis of radially migrating cortical neurons. Furthermore, detailed characterization of migrating neurons, such as migration speed, speed profiles, as well as radial orientation changes, is possible. The method can easily be adapted to perform functional analyses of genes of interest in radially migrating cortical neurons by loss and gain of function as well as rescue experiments. Time-lapse imaging of migrating neurons is a state-of-the-art technique that once established is a potent tool to study the development of the cerebral cortex in mouse models of neuronal migration disorders.


Assuntos
Córtex Cerebral/embriologia , Neurônios/citologia , Técnicas de Cultura de Órgãos/métodos , Imagem com Lapso de Tempo/métodos , Animais , Encéfalo/citologia , Encéfalo/embriologia , Proteínas de Transporte/genética , Movimento Celular/fisiologia , Córtex Cerebral/citologia , Eletroporação , Feminino , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Camundongos , Mutação , Neurônios/fisiologia , Proteínas Nucleares/genética , Gravidez , Imagem com Lapso de Tempo/instrumentação
7.
Neuron ; 87(2): 311-25, 2015 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-26182416

RESUMO

During neocortical development, neurons undergo polarization, oriented migration, and layer-type-specific differentiation. The transcriptional programs underlying these processes are not completely understood. Here, we show that the transcription factor Bcl11a regulates polarity and migration of upper layer neurons. Bcl11a-deficient late-born neurons fail to correctly switch from multipolar to bipolar morphology, resulting in impaired radial migration. We show that the expression of Sema3c is increased in migrating Bcl11a-deficient neurons and that Bcl11a is a direct negative regulator of Sema3c transcription. In vivo gain-of-function and rescue experiments demonstrate that Sema3c is a major downstream effector of Bcl11a required for the cell polarity switch and for the migration of upper layer neurons. Our data uncover a novel Bcl11a/Sema3c-dependent regulatory pathway used by migrating cortical neurons.


Assuntos
Proteínas de Transporte/fisiologia , Movimento Celular/genética , Córtex Cerebral/citologia , Córtex Cerebral/embriologia , Neurônios/fisiologia , Proteínas Nucleares/fisiologia , Semaforinas/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Proteínas de Transporte/genética , Diferenciação Celular/genética , Polaridade Celular/genética , Embrião de Mamíferos , Regulação da Expressão Gênica no Desenvolvimento/genética , Células HEK293 , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Humanos , Técnicas In Vitro , Camundongos , Camundongos Transgênicos , Análise em Microsséries , Mutação/genética , Proteínas do Tecido Nervoso/genética , Proteínas Nucleares/genética , Técnicas de Cultura de Órgãos , Semaforinas/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
8.
J Vis Exp ; (97)2015 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-25866930

RESUMO

Mouse genetics offers a powerful tool determining the role of specific genes during development. Analyzing the resulting phenotypes by immunohistochemical and molecular methods provides information of potential target genes and signaling pathways. To further elucidate specific regulatory mechanisms requires a system allowing the manipulation of only a small number of cells of a specific tissue by either overexpression, ablation or re-introduction of specific genes and follow their fate during development. To achieve this ex utero electroporation of hippocampal structures, especially the dentate gyrus, followed by organotypic slice culture provides such a tool. Using this system to generate mosaic deletions allows determining whether the gene of interest regulates cell-autonomously developmental processes like progenitor cell proliferation or neuronal differentiation. Furthermore it facilitates the rescue of phenotypes by re-introducing the deleted gene or its target genes. In contrast to in utero electroporation the ex utero approach improves the rate of successfully targeting deeper layers of the brain like the dentate gyrus. Overall ex utero electroporation and organotypic slice culture provide a potent tool to study regulatory mechanisms in a semi-native environment mirroring endogenous conditions.


Assuntos
Giro Denteado/fisiologia , Eletroporação/métodos , Técnicas de Cultura de Órgãos/métodos , Animais , Giro Denteado/citologia , Giro Denteado/embriologia , Desmoplaquinas/fisiologia , Regulação para Baixo , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Camundongos , Gravidez , Proteínas Repressoras/fisiologia , Análise de Célula Única/métodos , Proteínas Supressoras de Tumor/fisiologia , Regulação para Cima
9.
PLoS One ; 8(11): e77928, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24223744

RESUMO

Interneurons in the dorsal spinal cord process and relay innocuous and nociceptive somatosensory information from cutaneous receptors that sense touch, temperature and pain. These neurons display a well-defined organization with respect to their afferent innervation. Nociceptive afferents innervate lamina I and II, while cutaneous mechanosensory afferents primarily innervate sensory interneurons that are located in lamina III-IV. In this study, we outline a combinatorial transcription factor code that defines nine different inhibitory and excitatory interneuron populations in laminae III-IV of the postnatal cord. This transcription factor code reveals a high degree of molecular diversity in the neurons that make up laminae III-IV, and it lays the foundation for systematically analyzing and manipulating these different neuronal populations to assess their function. In addition, we find that many of the transcription factors that are expressed in the dorsal spinal cord at early postnatal times continue to be expressed in the adult, raising questions about their function in mature neurons and opening the door to their genetic manipulation in adult animals.


Assuntos
Interneurônios/metabolismo , Células do Corno Posterior/metabolismo , Fatores de Transcrição/metabolismo , Animais , Interneurônios/classificação , Mecanotransdução Celular , Camundongos , Camundongos Transgênicos , Células Receptoras Sensoriais/classificação , Células Receptoras Sensoriais/metabolismo , Medula Espinal/citologia , Fatores de Transcrição/genética , Transcriptoma
10.
EMBO J ; 31(13): 2922-36, 2012 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-22588081

RESUMO

The development of the dentate gyrus is characterized by distinct phases establishing a durable stem-cell pool required for postnatal and adult neurogenesis. Here, we report that Bcl11b/Ctip2, a zinc finger transcription factor expressed in postmitotic neurons, plays a critical role during postnatal development of the dentate gyrus. Forebrain-specific ablation of Bcl11b uncovers dual phase-specific functions of Bcl11b demonstrated by feedback control of the progenitor cell compartment as well as regulation of granule cell differentiation, leading to impaired spatial learning and memory in mutants. Surprisingly, we identified Desmoplakin as a direct transcriptional target of Bcl11b. Similarly to Bcl11b, postnatal neurogenesis and granule cell differentiation are impaired in Desmoplakin mutants. Re-expression of Desmoplakin in Bcl11b mutants rescues impaired neurogenesis, suggesting Desmoplakin to be an essential downstream effector of Bcl11b in hippocampal development. Together, our data define an important novel regulatory pathway in hippocampal development, by linking transcriptional functions of Bcl11b to Desmoplakin, a molecule known to act on cell adhesion.


Assuntos
Giro Denteado/fisiologia , Neurogênese/fisiologia , Proteínas Repressoras/fisiologia , Proteínas Supressoras de Tumor/fisiologia , Animais , Animais Recém-Nascidos , Giro Denteado/citologia , Giro Denteado/crescimento & desenvolvimento , Desmoplaquinas/fisiologia , Feminino , Transtornos de Aprendizagem/metabolismo , Transtornos de Aprendizagem/fisiopatologia , Masculino , Transtornos da Memória/metabolismo , Transtornos da Memória/fisiopatologia , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Prosencéfalo/citologia , Prosencéfalo/metabolismo , Proteínas Repressoras/genética , Células-Tronco/fisiologia , Proteínas Supressoras de Tumor/genética
11.
Development ; 139(10): 1831-41, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22491945

RESUMO

Dorsal spinal cord neurons receive and integrate somatosensory information provided by neurons located in dorsal root ganglia. Here we demonstrate that dorsal spinal neurons require the Krüppel-C(2)H(2) zinc-finger transcription factor Bcl11a for terminal differentiation and morphogenesis. The disrupted differentiation of dorsal spinal neurons observed in Bcl11a mutant mice interferes with their correct innervation by cutaneous sensory neurons. To understand the mechanism underlying the innervation deficit, we characterized changes in gene expression in the dorsal horn of Bcl11a mutants and identified dysregulated expression of the gene encoding secreted frizzled-related protein 3 (sFRP3, or Frzb). Frzb mutant mice show a deficit in the innervation of the spinal cord, suggesting that the dysregulated expression of Frzb can account in part for the phenotype of Bcl11a mutants. Thus, our genetic analysis of Bcl11a reveals essential functions of this transcription factor in neuronal morphogenesis and sensory wiring of the dorsal spinal cord and identifies Frzb, a component of the Wnt pathway, as a downstream acting molecule involved in this process.


Assuntos
Proteínas de Transporte/metabolismo , Gânglios Espinais/citologia , Neurônios/citologia , Proteínas Nucleares/metabolismo , Medula Espinal/citologia , Animais , Proteínas de Transporte/genética , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , Células Cultivadas , Imunoprecipitação da Cromatina , Eletrofisiologia , Gânglios Espinais/metabolismo , Hibridização In Situ , Camundongos , Camundongos Knockout , Morfogênese/genética , Morfogênese/fisiologia , Neurônios/metabolismo , Proteínas Nucleares/genética , Reação em Cadeia da Polimerase em Tempo Real , Células Receptoras Sensoriais/citologia , Células Receptoras Sensoriais/metabolismo , Medula Espinal/metabolismo
12.
Mol Cell Biol ; 32(13): 2467-78, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22508986

RESUMO

Mitogen-activated protein kinase-activated protein (MAPKAP) kinase 5 (MK5) deficiency is associated with reduced extracellular signal-regulated kinase 3 (ERK3) (mitogen-activated protein kinase 6) levels, hence we utilized the MK5 knockout mouse model to analyze the physiological functions of the ERK3/MK5 signaling module. MK5-deficient mice displayed impaired dendritic spine formation in mouse hippocampal neurons in vivo. We performed large-scale interaction screens to understand the neuronal functions of the ERK3/MK5 pathway and identified septin7 (Sept7) as a novel interacting partner of ERK3. ERK3/MK5/Sept7 form a ternary complex, which can phosphorylate the Sept7 regulators Binders of Rho GTPases (Borgs). In addition, the brain-specific nucleotide exchange factor kalirin-7 (Kal7) was identified as an MK5 interaction partner and substrate protein. In transfected primary neurons, Sept7-dependent dendrite development and spine formation are stimulated by the ERK3/MK5 module. Thus, the regulation of neuronal morphogenesis is proposed as the first physiological function of the ERK3/MK5 signaling module.


Assuntos
Dendritos/metabolismo , Dendritos/ultraestrutura , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteína Quinase 6 Ativada por Mitógeno/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Septinas/metabolismo , Animais , Sequência de Bases , Primers do DNA/genética , Reguladores de Proteínas de Ligação ao GTP/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Células HEK293 , Células HeLa , Hipocampo/citologia , Hipocampo/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/química , Peptídeos e Proteínas de Sinalização Intracelular/deficiência , Peptídeos e Proteínas de Sinalização Intracelular/genética , Sistema de Sinalização das MAP Quinases , Camundongos , Camundongos Knockout , Proteína Quinase 6 Ativada por Mitógeno/química , Proteína Quinase 6 Ativada por Mitógeno/genética , Modelos Neurológicos , Complexos Multiproteicos/química , Complexos Multiproteicos/metabolismo , Neurogênese/fisiologia , Neurônios/metabolismo , Neurônios/ultraestrutura , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/deficiência , Proteínas Serina-Treonina Quinases/genética , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Septinas/química , Septinas/genética , Transfecção
13.
FEBS J ; 278(2): 371-82, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21126319

RESUMO

Regulation of energy homeostasis is mainly mediated by factors in the hypothalamus and the brainstem. Understanding these regulatory mechanisms is of great clinical relevance in the treatment of obesity and related diseases. The homeobox gene Sax2 is expressed predominantly in the brainstem, in the vicinity of serotonergic neurons, and in the ventral neural tube starting during early development. Previously, we have shown that the loss of function of the Sax2 gene in mouse causes growth retardation starting at birth and a high rate of postnatal lethality, as well as a dramatic metabolic phenotype. To further define the role of Sax2 in energy homeostasis, age-matched adult wild-type, Sax2 heterozygous and null mutant animals were exposed to a high-fat diet. Although food uptake among the different groups was comparable, Sax2 null mutants fed a high-fat diet exhibited a significantly lower weight gain compared to control animals. Unlike their counterparts, Sax2 null mutants did not develop insulin resistance and exhibited significantly lower leptin levels under both standard chow and high-fat diet conditions. Furthermore, neuropeptide Y, an important regulator of energy homeostasis, was significantly decreased in the forebrain of Sax2 null mutants on a high-fat diet. These data strongly suggest a critical role for Sax2 gene expression in diet-induced obesity. Sax2 gene expression may be required to allow the coordinated crosstalk of factors involved in the maintenance of energy homeostasis, possibly regulating the transcription of specific factors involved in energy balance.


Assuntos
Gorduras na Dieta/farmacologia , Proteínas de Homeodomínio/metabolismo , Proteínas Nucleares/metabolismo , Obesidade/induzido quimicamente , Obesidade/prevenção & controle , Fatores de Transcrição/metabolismo , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/efeitos dos fármacos , Tecido Adiposo Branco/metabolismo , Animais , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Temperatura Corporal/fisiologia , Peso Corporal/efeitos dos fármacos , Peso Corporal/fisiologia , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Ingestão de Alimentos/fisiologia , Metabolismo Energético/fisiologia , Feminino , Expressão Gênica/efeitos dos fármacos , Expressão Gênica/genética , Glicogênio/metabolismo , Heterozigoto , Proteínas de Homeodomínio/genética , Insulina/sangue , Leptina/sangue , Metabolismo dos Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Mutantes , Neuropeptídeo Y/genética , Neuropeptídeo Y/metabolismo , Proteínas Nucleares/genética , Obesidade/metabolismo , Pró-Opiomelanocortina/genética , Pró-Opiomelanocortina/metabolismo , Serotonina/metabolismo , Caracteres Sexuais , Fatores de Transcrição/genética
14.
Dev Dyn ; 237(12): 3557-64, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18773496

RESUMO

Only very few left/right asymmetrically expressed genes are known in the mammalian embryo. In a screen for novel factors we identified the gene encoding the neuropeptide Galanin in mouse. At embryonic day (E) 8.5 asymmetric mRNA transcription was found in the left half of the linear heart tube. During heart looping and morphogenesis expression became restricted to the atrio-ventricular (AV) canal, followed by specific staining of the AV-node and AV-rings in the four-chambered heart. Expression was inverted in inv/inv and randomized in homozygous iv mutant embryos. Left-sided heart-specific transcription of mouse Gal thus should be controlled by the left-right pathway. The asymmetric pattern was retained in cryptic mutant embryos, in which the Nodal signaling cascade is disrupted. Surprisingly, Pitx2c was found to be expressed in 50% of cryptic mutant hearts as well, suggesting that some aspects of asymmetric gene expression in the heart are independent of cryptic.


Assuntos
Padronização Corporal , Galanina/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Coração/embriologia , Miocárdio/metabolismo , Animais , Encéfalo/embriologia , Encéfalo/metabolismo , Galanina/genética , Peptídeos e Proteínas de Sinalização Intercelular/genética , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Camundongos , Proteína Nodal/metabolismo , Xenopus laevis/embriologia , Xenopus laevis/metabolismo
15.
Adv Anat Embryol Cell Biol ; 190: 1-65, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17432114

RESUMO

Neuregulins (NRGs) comprise a large family of EGF-like signaling molecules involved in cell-cell communication during development and disease. The neuregulin family of ligands has four members: NRG1, NRG2, NRG3, and NRG4. Relatively little is known about the biological functions of the NRG2, 3, and 4 proteins. In contrast, the NRG1 proteins have been demonstrated to play important roles during the development of the nervous system, heart, and mammary glands. For example, NRG1 has essential functions in the development of neural crest cells and some of their major derivatives, like Schwann cells and sympathetic neurons. NRG1 controls the trabeculation of the myocardial musculature and the ductal differentiation of the mammary epithelium. Moreover, there is emerging evidence for the involvement of NRG signals in the development and function of several other organ systems, and in human disease, including breast cancer and schizophrenia. Many different isoforms of the Neuregulin-1 gene are synthesized. Such isoforms differ in their tissue-specific expression patterns and their biological activities, thereby contributing to the great diversity of the in vivo functions of NRG1. Neuregulins transmit their signals to target cells by interacting with transmembrane tyrosine kinase receptors of the ErbB family. This family includes four members, the epidermal growth factor receptor (EGF-R, ErbB1, ErbB2, ErbB3, and ErbB4). Receptor-ligand interaction induces the heterodimerization of receptor monomers, which in turn results in the activation of intracellular signaling cascades and the induction of cellular responses including proliferation, migration, differentiation, and survival or apoptosis. In vivo, functional NRG1 receptors are heterodimers composed of ErbB2 with either an ErbB3, or ErbB4 molecule. The tissue-specific distribution of the different receptor types further contributes to the diversity and specificity of the biological functions of this signaling pathway. It is a typical feature of the Neuregulin-1/ErbB signaling pathway to control sequential steps during the development of a particular organ system. For example, this pathway functions in early precursor proliferation, maturation, as well as in the myelination of Schwann cells. The systematic analysis of genetic models that have been established by the help of conventional as well as conditional gene targeting strategies in mice was instrumental for the uncovering of the multitude of biological functions of this signaling system. In this review the basic biology of the Neuregulin-1/ErbB system and how it relates to the in vivo functions were discussed with special emphasis to transgenic techniques in mice.


Assuntos
Receptores ErbB/metabolismo , Neuregulina-1/metabolismo , Receptor ErbB-2/metabolismo , Receptor ErbB-3/metabolismo , Transdução de Sinais , Animais , Receptores ErbB/genética , Cardiopatias/genética , Cardiopatias/metabolismo , Cardiopatias/patologia , Humanos , Modelos Biológicos , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patologia , Neuregulina-1/genética , Receptor ErbB-2/genética , Receptor ErbB-3/genética , Receptor ErbB-4 , Células de Schwann/metabolismo , Células de Schwann/patologia
16.
Dev Dyn ; 234(3): 767-71, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16193514

RESUMO

The dorsal spinal cord processes somatosensory information and relays it to higher brain centers and to motoneurons in the ventral spinal horn. These functions reside in a large number of distinct sensory interneurons that are organized in specific laminae within the dorsal spinal horn. Homeodomain and bHLH transcription factors can control the development of neuronal cell types in the dorsal horn. Here, we demonstrate that the murine homeodomain transcription factor Gbx1 is expressed specifically in a subset of Lbx1(+) (class B) neurons in the dorsal horn. Expression of Gbx1 in the dorsal spinal cord depends on Lbx1 function. Immunohistological analyses revealed that Gbx1 identifies a distinct population of late-born, Lhx1/5(+), Pax2(+) neurons. In the perinatal period as well as in the adult spinal cord, Gbx1 marks a subpopulation of GABAergic neurons. The expression of Gbx1 suggests that it controls development of a specific subset of GABAergic neurons in the dorsal horn of the spinal cord.


Assuntos
Proteínas de Homeodomínio/metabolismo , Medula Espinal/citologia , Medula Espinal/embriologia , Ácido gama-Aminobutírico/metabolismo , Animais , DNA Complementar/genética , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Homeodomínio/química , Proteínas de Homeodomínio/genética , Camundongos , Medula Espinal/metabolismo , Fatores de Tempo
17.
Genes Dev ; 19(6): 733-43, 2005 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-15769945

RESUMO

Neurons of the dorsal horn integrate and relay sensory information and arise during development in the dorsal spinal cord, the alar plate. Class A and B neurons emerge in the dorsal and ventral alar plate, differ in their dependence on roof plate signals for specification, and settle in the deep and superficial dorsal horn, respectively. We show here that the basic helix-loop-helix (bHLH) gene Olig3 is expressed in progenitor cells that generate class A (dI1-dI3) neurons and that Olig3 is an important factor in the development of these neuronal cell types. In Olig3 mutant mice, the development of class A neurons is impaired; dI1 neurons are generated in reduced numbers, whereas dI2 and dI3 neurons are misspecified and assume the identity of class B neurons. Conversely, Olig3 represses the emergence of class B neurons in the chick spinal cord. We conclude that Olig3 expression distinguishes the two major classes of progenitors in the dorsal spinal cord and determines the distinct specification program of class A neurons.


Assuntos
Diferenciação Celular/fisiologia , Camundongos/embriologia , Células do Corno Posterior/embriologia , Medula Espinal/embriologia , Fatores de Transcrição/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Southern Blotting , Bromodesoxiuridina , Embrião de Galinha , Eletroporação , Imunofluorescência , Técnicas de Transferência de Genes , Vetores Genéticos , Hibridização In Situ , Mutação/genética , Células do Corno Posterior/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Medula Espinal/metabolismo , Células-Tronco/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/fisiologia
18.
Proc Natl Acad Sci U S A ; 99(13): 8880-5, 2002 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-12072561

RESUMO

The ErbB2 (Her2) proto-oncogene encodes a receptor tyrosine kinase, which is frequently amplified and overexpressed in human tumors. ErbB2 provides the target for a novel and effective antibody-based therapy (Trastuzumab/Herceptin) used for the treatment of mammary carcinomas. However, cardiomyopathies develop in a proportion of patients treated with Trastuzumab, and the incidence of such complications is increased by combination with standard chemotherapy. Gene ablation studies have previously demonstrated that the ErbB2 receptor, together with its coreceptor ErbB4 and the ligand Neuregulin-1, are essential for normal development of the heart ventricle. We use here Cre-loxP technology to mutate ErbB2 specifically in ventricular cardiomyocytes. Conditional mutant mice develop a severe dilated cardiomyopathy, with signs of cardiac dysfunction generally appearing by the second postnatal month. We infer that signaling from the ErbB2 receptor, which is enriched in T-tubules in cardiomyocytes, is crucial for adult heart function. Conditional ErbB2 mutant mice provide a model of dilated cardiomyopathy. In particular, they will allow a rigorous assessment of the role of ErbB2 in the heart and provide insight into the molecular mechanisms that underlie the adverse effects of anti-ErbB2 antibodies.


Assuntos
Cardiomiopatia Dilatada/genética , Mutação , Miocárdio/metabolismo , Receptor ErbB-2/fisiologia , Animais , Camundongos , Camundongos Mutantes , Receptor ErbB-2/genética
19.
Cell ; 109(6): 693-705, 2002 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-12086669

RESUMO

Nerves and blood vessels are branched structures, but whether their branching patterns are established independently or coordinately is not clear. Here we show that arteries, but not veins, are specifically aligned with peripheral nerves in embryonic mouse limb skin. Mutations that eliminate peripheral sensory nerves or Schwann cells prevent proper arteriogenesis, while those that disorganize the nerves maintain the alignment of arteries with misrouted axons. In vitro, sensory neurons or Schwann cells can induce arterial marker expression in isolated embryonic endothelial cells, and VEGF(164/120) is necessary and sufficient to mediate this induction. These data suggest that peripheral nerves provide a template that determines the organotypic pattern of blood vessel branching and arterial differentiation in the skin, via local secretion of VEGF.


Assuntos
Artérias/citologia , Neurônios Aferentes/metabolismo , Neurônios Aferentes/fisiologia , Animais , Artérias/embriologia , Artérias/metabolismo , Diferenciação Celular , Movimento Celular , Fatores de Crescimento Endotelial/metabolismo , Fatores de Crescimento Endotelial/fisiologia , Extremidades/embriologia , Imuno-Histoquímica , Hibridização In Situ , Linfocinas/metabolismo , Linfocinas/fisiologia , Camundongos , Microscopia de Fluorescência , Músculo Liso/citologia , Mutação , Neurônios/metabolismo , Receptor ErbB-3/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Células de Schwann/metabolismo , Pele/embriologia , Fator A de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio Vascular
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