Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
1.
J Neurochem ; 129(6): 966-79, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24611815

RESUMEN

Restoration of correct neural activity following central nervous system (CNS) damage requires the replacement of degenerated axons with newly outgrowing, functional axons. Unfortunately, spontaneous regeneration is largely lacking in the adult mammalian CNS. In order to establish successful regenerative therapies, an improved understanding of axonal outgrowth and the various molecules influencing it, is highly needed. Matrix metalloproteinases (MMPs) constitute a family of zinc-dependent proteases that were sporadically reported to influence axon outgrowth. Using an ex vivo retinal explant model, we were able to show that broad-spectrum MMP inhibition reduces axon outgrowth of mouse retinal ganglion cells (RGCs), implicating MMPs as beneficial factors in axonal regeneration. Additional studies, using more specific MMP inhibitors and MMP-deficient mice, disclosed that both MMP-2 and MT1-MMP, but not MMP-9, are involved in this process. Furthermore, administration of a novel antibody to MT1-MMP that selectively blocks pro-MMP-2 activation revealed a functional co-involvement of these proteinases in determining RGC axon outgrowth. Subsequent immunostainings showed expression of both MMP-2 and MT1-MMP in RGC axons and glial cells. Finally, results from combined inhibition of MMP-2 and ß1-integrin were suggestive for a functional interaction between these molecules. Overall, our data indicate MMP-2 and MT1-MMP as promising axonal outgrowth-promoting molecules. Axonal regeneration in the central nervous system is lacking in adult mammals, thereby impeding recovery from injury to the nervous system. Matrix metalloproteinases (MMPs) constitute a family of zinc-dependent proteases that were sporadically reported to influence axon outgrowth. Inhibition of specific MMPs reduced neurite outgrowth from mouse retinal explants. Our data indicate MMP-2 and MT1-MMP as promising axonal outgrowth-promoting molecules and show a possible link between MMP-2 and ß1-integrin in axon outgrowth.


Asunto(s)
Axones/fisiología , Metaloproteinasa 2 de la Matriz/fisiología , Inhibidores de la Metaloproteinasa de la Matriz/farmacología , Metaloproteinasas de la Matriz Asociadas a la Membrana/fisiología , Células Ganglionares de la Retina/fisiología , Animales , Anticuerpos Bloqueadores/farmacología , Axones/efectos de los fármacos , Gelatinasas/farmacología , Procesamiento de Imagen Asistido por Computador , Inmunohistoquímica , Integrina beta1/farmacología , Integrina beta1/fisiología , Metaloproteinasa 9 de la Matriz/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Técnicas de Cultivo de Órganos , Células Ganglionares de la Retina/efectos de los fármacos , Células Ganglionares de la Retina/enzimología , Transducción de Señal/efectos de los fármacos , Transducción de Señal/fisiología
2.
Blood ; 119(21): 5048-56, 2012 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-22490679

RESUMEN

Lymphatic dysfunctions are associated with several human diseases, including lymphedema and metastatic spread of cancer. Although it is well recognized that lymphatic capillaries attach directly to interstitial matrix mainly composed of fibrillar type I collagen, the interactions occurring between lymphatics and their surrounding matrix have been overlooked. In this study, we demonstrate how matrix metalloproteinase (MMP)-2 drives lymphatic morphogenesis through Mmp2-gene ablation in mice, mmp2 knockdown in zebrafish and in 3D-culture systems, and through MMP2 inhibition. In all models used in vivo (3 murine models and thoracic duct development in zebrafish) and in vitro (lymphatic ring and spheroid assays), MMP2 blockage or down-regulation leads to reduced lymphangiogenesis or altered vessel branching. Our data show that lymphatic endothelial cell (LEC) migration through collagen fibers is affected by physical matrix constraints (matrix composition, density, and cross-linking). Transmission electron microscopy and confocal reflection microscopy using DQ-collagen highlight the contribution of MMP2 to mesenchymal-like migration of LECs associated with collagen fiber remodeling. Our findings provide new mechanistic insight into how LECs negotiate an interstitial type I collagen barrier and reveal an unexpected MMP2-driven collagenolytic pathway for lymphatic vessel formation and morphogenesis.


Asunto(s)
Linfangiogénesis/genética , Vasos Linfáticos/embriología , Metaloproteinasa 2 de la Matriz/metabolismo , Metaloproteinasa 2 de la Matriz/fisiología , Animales , Animales Modificados Genéticamente , Células Cultivadas , Colágeno Tipo I/metabolismo , Colagenasas/genética , Colagenasas/metabolismo , Colagenasas/fisiología , Embrión no Mamífero , Líquido Extracelular/enzimología , Líquido Extracelular/metabolismo , Femenino , Humanos , Vasos Linfáticos/metabolismo , Vasos Linfáticos/fisiología , Masculino , Metaloproteinasa 2 de la Matriz/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Pez Cebra
3.
Endocrinology ; 150(1): 530-9, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18801906

RESUMEN

Despite the known importance of thyroid hormones (THs) in vertebrate growth and development, the role of tissue-specific TH activation in early embryogenesis remains unclear. We therefore examined the function of type 2 iodothyronine deiodinase (D2), one of the two tissue-specific enzymes catalyzing the conversion of T4 to T3, in developing zebrafish embryos (Danio rerio). Microinjection of early embryos with antisense oligonucleotides targeting either the D2 translation start site or the splice junction between the first exon and intron induced delays in development and pigmentation, as determined through the measurement of otic vesicle length, head-trunk angle, and pigmentation index at 31 h after fertilization. The antisense-induced delays in developmental progression and pigmentation were reversible through treatment with T3, suggesting that these phenotypic effects may be due to the depletion of intracellular T3 levels. Additional evidence for this hypothesis was provided by quantitative RT-PCR analysis of TH receptor-beta expression in D2 knockdown embryos, revealing a significant down-regulation of this T3-induced transcript that could be reversed by T3 treatment. Tyrosinase expression was also down-regulated in D2 knockdown embryos to a greater degree than could be predicted by the observed delay in developmental progression, suggesting that reduced D2 activity and resultant low intracellular T3 availability may directly influence pigmentation in zebrafish. These data indicate that TH activation by D2 is essential for embryonic development and pigmentation in zebrafish.


Asunto(s)
Embrión no Mamífero/fisiología , Desarrollo Embrionario/fisiología , Yoduro Peroxidasa/metabolismo , Pigmentación/fisiología , Hormonas Tiroideas/fisiología , Animales , Cartilla de ADN , Embrión no Mamífero/efectos de los fármacos , Desarrollo Embrionario/efectos de los fármacos , Monofenol Monooxigenasa/genética , Oligonucleótidos Antisentido/farmacología , Pigmentación/efectos de los fármacos , Reacción en Cadena de la Polimerasa , ARN/genética , ARN/aislamiento & purificación , Receptores alfa de Hormona Tiroidea/genética , Receptores beta de Hormona Tiroidea/genética , Tiroxina/farmacología , Triyodotironina/farmacología , Pez Cebra , Yodotironina Deyodinasa Tipo II
4.
Clin Cancer Res ; 21(14): 3327-39, 2015 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-25805801

RESUMEN

PURPOSE: Activating ALK mutations are present in almost 10% of primary neuroblastomas and mark patients for treatment with small-molecule ALK inhibitors in clinical trials. However, recent studies have shown that multiple mechanisms drive resistance to these molecular therapies. We anticipated that detailed mapping of the oncogenic ALK-driven signaling in neuroblastoma can aid to identify potential fragile nodes as additional targets for combination therapies. EXPERIMENTAL DESIGN: To achieve this goal, transcriptome profiling was performed in neuroblastoma cell lines with the ALK(F1174L) or ALK(R1275Q) hotspot mutations, ALK amplification, or wild-type ALK following pharmacologic inhibition of ALK using four different compounds. Next, we performed cross-species genomic analyses to identify commonly transcriptionally perturbed genes in MYCN/ALK(F1174L) double transgenic versus MYCN transgenic mouse tumors as compared with the mutant ALK-driven transcriptome in human neuroblastomas. RESULTS: A 77-gene ALK signature was established and successfully validated in primary neuroblastoma samples, in a neuroblastoma cell line with ALK(F1174L) and ALK(R1275Q) regulable overexpression constructs and in other ALKomas. In addition to the previously established PI3K/AKT/mTOR, MAPK/ERK, and MYC/MYCN signaling branches, we identified that mutant ALK drives a strong upregulation of MAPK negative feedback regulators and upregulates RET and RET-driven sympathetic neuronal markers of the cholinergic lineage. CONCLUSIONS: We provide important novel insights into the transcriptional consequences and the complexity of mutant ALK signaling in this aggressive pediatric tumor. The negative feedback loop of MAPK pathway inhibitors may affect novel ALK inhibition therapies, whereas mutant ALK induced RET signaling can offer novel opportunities for testing ALK-RET oriented molecular combination therapies.


Asunto(s)
Fosfatasa Alcalina/genética , Resistencia a Antineoplásicos/genética , Quinasas de Proteína Quinasa Activadas por Mitógenos/metabolismo , Terapia Molecular Dirigida/métodos , Neuroblastoma/genética , Proteínas Proto-Oncogénicas c-ret/metabolismo , Animales , Western Blotting , Línea Celular Tumoral , Retroalimentación Fisiológica , Humanos , Ratones , Ratones Transgénicos , Neuroblastoma/metabolismo , Análisis de Secuencia por Matrices de Oligonucleótidos , Reacción en Cadena de la Polimerasa , Transcriptoma , Regulación hacia Arriba
5.
PLoS One ; 9(10): e109091, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25310091

RESUMEN

The selection and validation of stably expressed reference genes is a critical issue for proper RT-qPCR data normalization. In zebrafish expression studies, many commonly used reference genes are not generally applicable given their variability in expression levels under a variety of experimental conditions. Inappropriate use of these reference genes may lead to false interpretation of expression data and unreliable conclusions. In this study, we evaluated a novel normalization method in zebrafish using expressed repetitive elements (ERE) as reference targets, instead of specific protein coding mRNA targets. We assessed and compared the expression stability of a number of EREs to that of commonly used zebrafish reference genes in a diverse set of experimental conditions including a developmental time series, a set of different organs from adult fish and different treatments of zebrafish embryos including morpholino injections and administration of chemicals. Using geNorm and rank aggregation analysis we demonstrated that EREs have a higher overall expression stability compared to the commonly used reference genes. Moreover, we propose a limited set of ERE reference targets (hatn10, dna15ta1 and loopern4), that show stable expression throughout the wide range of experiments in this study, as strong candidates for inclusion as reference targets for qPCR normalization in future zebrafish expression studies. Our applied strategy to find and evaluate candidate expressed repeat elements for RT-qPCR data normalization has high potential to be used also for other species.


Asunto(s)
Perfilación de la Expresión Génica/normas , Reacción en Cadena en Tiempo Real de la Polimerasa/normas , Pez Cebra/genética , Animales , Expresión Génica , Perfilación de la Expresión Génica/métodos , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Estándares de Referencia
6.
PLoS One ; 8(1): e52915, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23326364

RESUMEN

BACKGROUND: Matrix metalloproteinases (MMPs) are members of the metzincin superfamily of proteinases that cleave structural elements of the extracellular matrix and many molecules involved in signal transduction. Although there is evidence that MMPs promote the proper development of retinotectal projections, the nature and working mechanisms of specific MMPs in retinal development remain to be elucidated. Here, we report a role for zebrafish Mmp14a, one of the two zebrafish paralogs of human MMP14, in retinal neurogenesis and retinotectal development. RESULTS: Whole mount in situ hybridization and immunohistochemical stainings for Mmp14a in developing zebrafish embryos reveal expression in the optic tectum, in the optic nerve and in defined retinal cell populations, including retinal ganglion cells (RGCs). Furthermore, Mmp14a loss-of-function results in perturbed retinoblast cell cycle kinetics and consequently, in a delayed retinal neurogenesis, differentiation and lamination. These Mmp14a-dependent retinal defects lead to microphthalmia and a significantly reduced innervation of the optic tectum (OT) by RGC axons. Mmp14b, on the contrary, does not appear to alter retinal neurogenesis or OT innervation. As mammalian MMP14 is known to act as an efficient MMP2-activator, we also explored and found a functional link and a possible co-involvement of Mmp2 and Mmp14a in zebrafish retinotectal development. CONCLUSION: Both the Mmp14a expression in the developing visual system and the Mmp14a loss-of-function phenotype illustrate a critical role for Mmp14a activity in retinal and retinotectal development.


Asunto(s)
Embrión no Mamífero/metabolismo , Metaloproteinasa 14 de la Matriz/genética , Proteínas de Pez Cebra/genética , Pez Cebra/genética , Animales , Animales Modificados Genéticamente , Embrión no Mamífero/citología , Embrión no Mamífero/embriología , Regulación del Desarrollo de la Expresión Génica , Regulación Enzimológica de la Expresión Génica , Técnicas de Silenciamiento del Gen , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Inmunohistoquímica , Hibridación in Situ , Isoenzimas/genética , Isoenzimas/metabolismo , Metaloproteinasa 14 de la Matriz/metabolismo , Metaloproteinasa 2 de la Matriz/genética , Metaloproteinasa 2 de la Matriz/metabolismo , Microftalmía/embriología , Microftalmía/genética , Microftalmía/metabolismo , Microscopía Confocal , Neurogénesis/genética , Lóbulo Óptico de Animales no Mamíferos/citología , Lóbulo Óptico de Animales no Mamíferos/embriología , Lóbulo Óptico de Animales no Mamíferos/metabolismo , Unión Proteica , Retina/embriología , Retina/metabolismo , Células Ganglionares de la Retina/metabolismo , Pez Cebra/embriología , Proteínas de Pez Cebra/metabolismo
7.
Development ; 134(24): 4381-93, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18039968

RESUMEN

During vertebrate development, signaling by the TGFbeta ligand Nodal is critical for mesoderm formation, correct positioning of the anterior-posterior axis, normal anterior and midline patterning, and left-right asymmetric development of the heart and viscera. Stimulation of Alk4/EGF-CFC receptor complexes by Nodal activates Smad2/3, leading to left-sided expression of target genes that promote asymmetric placement of certain internal organs. We identified Ttrap as a novel Alk4- and Smad3-interacting protein that controls gastrulation movements and left-right axis determination in zebrafish. Morpholino-mediated Ttrap knockdown increases Smad3 activity, leading to ectopic expression of snail1a and apparent repression of e-cadherin, thereby perturbing cell movements during convergent extension, epiboly and node formation. Thus, although the role of Smad proteins in mediating Nodal signaling is well-documented, the functional characterization of Ttrap provides insight into a novel Smad partner that plays an essential role in the fine-tuning of this signal transduction cascade.


Asunto(s)
Proteína smad3/metabolismo , Factor de Crecimiento Transformador beta/metabolismo , Péptidos y Proteínas Asociados a Receptores de Factores de Necrosis Tumoral/metabolismo , Proteínas de Pez Cebra/metabolismo , Pez Cebra/embriología , Pez Cebra/metabolismo , Receptores de Activinas/genética , Receptores de Activinas/metabolismo , Receptores de Activinas Tipo I , Animales , Secuencia de Bases , Tipificación del Cuerpo/genética , Tipificación del Cuerpo/fisiología , Cadherinas/genética , Cadherinas/metabolismo , Cartilla de ADN/genética , Gastrulación/genética , Gastrulación/fisiología , Regulación del Desarrollo de la Expresión Génica , Proteína Nodal , Oligorribonucleótidos Antisentido/genética , Transducción de Señal , Proteína smad3/genética , Factores de Transcripción de la Familia Snail , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Factor de Crecimiento Transformador beta/genética , Péptidos y Proteínas Asociados a Receptores de Factores de Necrosis Tumoral/genética , Pez Cebra/genética , Proteínas de Pez Cebra/genética
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA