RESUMEN
Despite the identification of numerous molecular pathways modulating cardiac hypertrophy its pathogenesis is not completely understood. In this study we define an unexpected role for Fibin ("fin bud initiation factor homolog") in cardiomyocyte hypertrophy. Via gene expression profiling in hypertrophic murine hearts after transverse aortic constriction we found a significant induction of Fibin. Moreover, Fibin was upregulated in another mouse model of cardiac hypertrophy (calcineurin-transgenics) as well as in patients with dilated cardiomyopathy. Immunoflourescence microscopy revealed subcellular localization of Fibin at the sarcomeric z-disc. Overexpression of Fibin in neonatal rat ventricular cardiomyocytes revealed a strong anti-hypertrophic effect through inhibiting both, NFAT- and SRF-dependent signalling. In contrast, transgenic mice with cardiac-restricted overexpression of Fibin developed dilated cardiomyopathy, accompanied by induction of hypertrophy-associated genes. Moreover, Fibin overexpression accelerated the progression to heart failure in the presence of prohypertrophic stimuli such as pressure overload and calcineurin overexpression. Histological and ultrastructural analyses surprisingly showed large protein aggregates containing Fibin. On the molecular level, aggregate formation was accompanied by an induction of the unfolded protein response subsequent UPR-mediated apoptosis and autophagy. Taken together, we identified Fibin as a novel potent negative regulator of cardiomyocyte hypertrophy in vitro. Yet, heart-specific Fibin overexpression in vivo causes development of a protein-aggregate-associated cardiomyopathy. Because of close similarities to myofibrillar myopathies, Fibin represents a candidate gene for cardiomyopathy and Fibin transgenic mice may provide additional mechanistic insight into aggregate formation in these diseases.
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Melanocytes are pigmented cells residing mostly in the skin and hair follicles of vertebrates, where they contribute to colouration and protection against UV-B radiation. However, the spectrum of their functions reaches far beyond that. For instance, these pigment-producing cells are found inside the inner ear, where they contribute to the hearing function, and in the heart, where they are involved in the electrical conductivity and support the stiffness of cardiac valves. The embryonic origin of such extracutaneous melanocytes is not clear. We took advantage of lineage-tracing experiments combined with 3D visualizations and gene knockout strategies to address this long-standing question. We revealed that Schwann cell precursors are recruited from the local innervation during embryonic development and give rise to extracutaneous melanocytes in the heart, brain meninges, inner ear, and other locations. In embryos with a knockout of the EdnrB receptor, a condition imitating Waardenburg syndrome, we observed only nerve-associated melanoblasts, which failed to detach from the nerves and to enter the inner ear. Finally, we looked into the evolutionary aspects of extracutaneous melanocytes and found that pigment cells are associated mainly with nerves and blood vessels in amphibians and fish. This new knowledge of the nerve-dependent origin of extracutaneous pigment cells might be directly relevant to the formation of extracutaneous melanoma in humans.
Asunto(s)
Encéfalo/fisiología , Oído Interno/fisiología , Corazón/fisiología , Meninges/fisiología , Sistema Nervioso/fisiopatología , Células de Schwann/fisiología , Anfibios/metabolismo , Anfibios/fisiología , Animales , Encéfalo/metabolismo , Linaje de la Célula/fisiología , Oído Interno/metabolismo , Desarrollo Embrionario/fisiología , Femenino , Peces/metabolismo , Peces/fisiología , Melanocitos/metabolismo , Melanocitos/fisiología , Meninges/metabolismo , Ratones , Sistema Nervioso/metabolismo , Embarazo , Receptor de Endotelina B/metabolismo , Células de Schwann/metabolismoRESUMEN
Autophagy is a cellular degradation process that has been implicated in diverse disease processes. The authors provide evidence that FYCO1, a component of the autophagic machinery, is essential for adaptation to cardiac stress. Although the absence of FYCO1 does not affect basal autophagy in isolated cardiomyocytes, it abolishes induction of autophagy after glucose deprivation. Likewise, Fyco1-deficient mice subjected to starvation or pressure overload are unable to respond with induction of autophagy and develop impaired cardiac function. FYCO1 overexpression leads to induction of autophagy in isolated cardiomyocytes and transgenic mouse hearts, thereby rescuing cardiac dysfunction in response to biomechanical stress.
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Infancy may represent a sensitive window for establishing food preferences that could affect the individual's long-term potential to establish healthy eating patterns. Our study was based on the hypothesis that preserving the natural flavor of the ingredients of commercially prepared complementary foods would increase the acceptance of new foods, especially vegetables. Frozen vegetable-based meals for infants were developed to preserve the natural taste of the ingredients better than sterilization of meals in jars. In a 3-month randomized, controlled intervention study, 51 infants were fed either frozen menus (intervention group) or commercial sterilized meals in jars (control group) on at least 5 days per week. Then the acceptability of a known vegetable-based puree was tested in comparison to an unknown puree, measuring the quantities consumed and also the mother's assessment of the infants' liking. In conclusion, the results of this study clearly indicated that infants fed vegetable-based frozen meals for 3 months accepted a new vegetable better than infants fed sterilized commercial meals in jars.
Asunto(s)
Preferencias Alimentarias , Alimentos Congelados , Alimentos Infantiles , Fenómenos Fisiológicos Nutricionales del Lactante , Verduras , Conducta Alimentaria , Femenino , Humanos , Lactante , Masculino , GustoRESUMEN
Familial exudative vitreoretinopathy (FEVR) is a human disease characterized by defective retinal angiogenesis and associated complications that can result in vision loss. Defective Wnt/ß-catenin signaling is an established cause of FEVR, whereas other molecular alterations contributing to the disease remain insufficiently understood. Here, we show that integrin-linked kinase (ILK), a mediator of cell-matrix interactions, is indispensable for retinal angiogenesis. Inactivation of the murine Ilk gene in postnatal endothelial cells results in sprouting defects, reduced endothelial proliferation and disruption of the blood-retina barrier, resembling phenotypes seen in established mouse models of FEVR. Retinal vascularization defects are phenocopied by inducible inactivation of the gene for α-parvin (Parva), an interactor of ILK. Screening genomic DNA samples from exudative vitreoretinopathy patients identifies three distinct mutations in human ILK, which compromise the function of the gene product in vitro. Together, our data suggest that defective cell-matrix interactions are linked to Wnt signaling and FEVR.
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Barrera Hematorretinal/metabolismo , Células Endoteliales/metabolismo , Vitreorretinopatías Exudativas Familiares/genética , Neovascularización Fisiológica/genética , Proteínas Serina-Treonina Quinasas/genética , Vasos Retinianos/crecimiento & desarrollo , Animales , Células Endoteliales/citología , Femenino , Células Endoteliales de la Vena Umbilical Humana , Humanos , Masculino , Ratones , Proteínas de Microfilamentos/genética , Fenotipo , Vía de Señalización Wnt/genéticaRESUMEN
Gene expression profiles of more than 10,000 individual microglial cells isolated from cortex and hippocampus of male and female AppNL-G-F mice over time demonstrate that progressive amyloid-ß accumulation accelerates two main activated microglia states that are also present during normal aging. Activated response microglia (ARMs) are composed of specialized subgroups overexpressing MHC type II and putative tissue repair genes (Dkk2, Gpnmb, and Spp1) and are strongly enriched with Alzheimer's disease (AD) risk genes. Microglia from female mice progress faster in this activation trajectory. Similar activated states are also found in a second AD model and in human brain. Apoe, the major genetic risk factor for AD, regulates the ARMs but not the interferon response microglia (IRMs). Thus, the ARMs response is the converging point for aging, sex, and genetic AD risk factors.
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Envejecimiento/patología , Enfermedad de Alzheimer/patología , Biomarcadores/metabolismo , Encéfalo/patología , Modelos Animales de Enfermedad , Microglía/patología , Placa Amiloide/patología , Envejecimiento/genética , Envejecimiento/metabolismo , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/fisiología , Animales , Biomarcadores/análisis , Encéfalo/metabolismo , Femenino , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados para ApoE , Ratones Transgénicos , Microglía/metabolismo , Placa Amiloide/genética , Placa Amiloide/metabolismo , Presenilinas/fisiología , Caracteres SexualesRESUMEN
Macrophages are highly heterogeneous tissue-resident immune cells that perform a variety of tissue-supportive functions. The current paradigm dictates that intestinal macrophages are continuously replaced by incoming monocytes that acquire a pro-inflammatory or tissue-protective signature. Here, we identify a self-maintaining population of macrophages that arise from both embryonic precursors and adult bone marrow-derived monocytes and persists throughout adulthood. Gene expression and imaging studies of self-maintaining macrophages revealed distinct transcriptional profiles that reflect their unique localization (i.e., closely positioned to blood vessels, submucosal and myenteric plexus, Paneth cells, and Peyer's patches). Depletion of self-maintaining macrophages resulted in morphological abnormalities in the submucosal vasculature and loss of enteric neurons, leading to vascular leakage, impaired secretion, and reduced intestinal motility. These results provide critical insights in intestinal macrophage heterogeneity and demonstrate the strategic role of self-maintaining macrophages in gut homeostasis and intestinal physiology.
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Intestinos/inmunología , Macrófagos/inmunología , Animales , Tipificación del Cuerpo/fisiología , Diferenciación Celular/genética , Diferenciación Celular/inmunología , Motilidad Gastrointestinal/inmunología , Motilidad Gastrointestinal/fisiología , Homeostasis , Inflamación/inmunología , Mucosa Intestinal/inmunología , Intestino Delgado/metabolismo , Ratones , Monocitos/metabolismo , Neuronas/metabolismo , Fagocitos/inmunología , TranscriptomaRESUMEN
Pericytes adhere to the abluminal surface of endothelial tubules and are required for the formation of stable vascular networks. Defective endothelial cell-pericyte interactions are frequently observed in diseases characterized by compromised vascular integrity such as diabetic retinopathy. Many functional properties of pericytes and their exact role in the regulation of angiogenic blood vessel growth remain elusive. Here we show that pericytes promote endothelial sprouting in the postnatal retinal vasculature. Using genetic and pharmacological approaches, we show that the expression of vascular endothelial growth factor receptor 1 (VEGFR1) by pericytes spatially restricts VEGF signalling. Angiogenic defects caused by pericyte depletion are phenocopied by intraocular injection of VEGF-A or pericyte-specific inactivation of the murine gene encoding VEGFR1. Our findings establish that pericytes promote endothelial sprouting, which results in the loss of side branches and the enlargement of vessels when pericyte function is impaired or lost.
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Células Endoteliales/metabolismo , Ojo/irrigación sanguínea , Neovascularización Fisiológica/fisiología , Pericitos/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismo , Receptor 1 de Factores de Crecimiento Endotelial Vascular/metabolismo , Animales , Capilares/citología , Capilares/crecimiento & desarrollo , Línea Celular , Toxina Diftérica/toxicidad , Células Endoteliales/citología , Factor de Crecimiento Similar a EGF de Unión a Heparina/metabolismo , Células Endoteliales de la Vena Umbilical Humana , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Pericitos/citología , Receptor beta de Factor de Crecimiento Derivado de Plaquetas/genética , Retina/metabolismo , Transducción de Señal , Receptor 1 de Factores de Crecimiento Endotelial Vascular/genéticaRESUMEN
Endothelial sprouting and proliferation are tightly coordinated processes mediating the formation of new blood vessels during physiological and pathological angiogenesis. Endothelial tip cells lead sprouts and are thought to suppress tip-like behaviour in adjacent stalk endothelial cells by activating Notch. Here, we show with genetic experiments in postnatal mice that the level of active Notch signalling is more important than the direct Dll4-mediated cell-cell communication between endothelial cells. We identify endothelial expression of VEGF-A and of the chemokine receptor CXCR4 as key processes controlling Notch-dependent vessel growth. Surprisingly, genetic experiments targeting endothelial tip cells in vivo reveal that they retain their function without Dll4 and are also not replaced by adjacent, Dll4-positive cells. Instead, activation of Notch directs tip-derived endothelial cells into developing arteries and thereby establishes that Dll4-Notch signalling couples sprouting angiogenesis and artery formation.
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Células Endoteliales/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas de la Membrana/metabolismo , Neovascularización Fisiológica , Receptor Notch1/metabolismo , Arteria Retiniana/metabolismo , Proteínas Adaptadoras Transductoras de Señales , Animales , Proteínas de Unión al Calcio , Comunicación Celular , Diferenciación Celular , Linaje de la Célula , Movimiento Celular , Proliferación Celular , Células Cultivadas , Femenino , Regulación de la Expresión Génica , Genotipo , Péptidos y Proteínas de Señalización Intracelular/genética , Proteína Jagged-1/genética , Proteína Jagged-1/metabolismo , Masculino , Proteínas de la Membrana/genética , Ratones Endogámicos C57BL , Ratones Transgénicos , Fenotipo , Receptor Notch1/genética , Receptores CXCR4/genética , Receptores CXCR4/metabolismo , Arteria Retiniana/citología , Transducción de Señal , Factores de Tiempo , Factor A de Crecimiento Endotelial Vascular/genética , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
Food neophobia (FN) is described as the rejection to eat unknown foods. Because only little is known about the role of FN in adolescence the aim of this study was to examine potential determinants of FN and associations with dietary habits of DONALD study participants. FN was measured with Pliner's and Hobden's Food Neophobia Scale (FN Score (FNS): range 10-70) in 166 10-18-year-old adolescents. Participants' age, sex, body weight status and duration of breast-feeding as well as parents' FN and educational status were considered as determinants. Energy intake, distribution of macronutrients and two variety scores were calculated from 3-day weighed dietary records. Multivariable general linear models were performed for data analyses. Boys and girls did not differ in their FNS (median (Min-Max): boys 31 (10-58), girls 32 (14-59)). Increasing age (p = 0.010) and duration of total breast-feeding (p = 0.006) were associated with decreasing FNS in girls only. FN was further positively associated with parental FN in the total sample (p = 0.004). FN was negatively associated with protein intake in the total sample (p = 0.017). The overall low level of FN in the DONALD study can be ascribed to the low level of FN in adolescence in general. Congruently with other studies, age and breast-feeding duration were identified as determinants of girls' FN and parental FN was identified as determinant of FN in the total sample. Further, our results indicate that FN leads to reduced protein intakes. Dietary variety was not strongly affected, possibly because of a broad variety of food supply in Germany.
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Conducta de Elección , Dieta , Preferencias Alimentarias/psicología , Adolescente , Índice de Masa Corporal , Peso Corporal , Niño , Estudios Transversales , Registros de Dieta , Escolaridad , Femenino , Frutas , Alemania , Humanos , Masculino , Evaluación Nutricional , Relaciones Padres-Hijo , Padres/psicología , Encuestas y Cuestionarios , VerdurasRESUMEN
Tissue vascularization entails the formation of a blood vessel plexus, which remodels into arteries and veins. Here we show, by using time-lapse imaging of zebrafish fin regeneration and genetic lineage tracing of endothelial cells in the mouse retina, that vein-derived endothelial tip cells contribute to emerging arteries. Our movies uncover that arterial-fated tip cells change migration direction and migrate backwards within the expanding vascular plexus. This behaviour critically depends on chemokine receptor cxcr4a function. We show that the relevant Cxcr4a ligand Cxcl12a selectively accumulates in newly forming bone tissue even when ubiquitously overexpressed, pointing towards a tissue-intrinsic mode of chemokine gradient formation. Furthermore, we find that cxcr4a mutant cells can contribute to developing arteries when in association with wild-type cells, suggesting collective migration of endothelial cells. Together, our findings reveal specific cell migratory behaviours in the developing blood vessel plexus and uncover a conserved mode of artery formation.
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Arterias/crecimiento & desarrollo , Células Endoteliales/metabolismo , Endotelio Vascular/metabolismo , Neovascularización Fisiológica , Receptores CXCR4/metabolismo , Venas/crecimiento & desarrollo , Proteínas de Pez Cebra/metabolismo , Aletas de Animales/irrigación sanguínea , Aletas de Animales/citología , Aletas de Animales/crecimiento & desarrollo , Aletas de Animales/metabolismo , Animales , Animales Modificados Genéticamente , Arterias/citología , Arterias/metabolismo , Linaje de la Célula/genética , Movimiento Celular , Quimiocina CXCL12/genética , Quimiocina CXCL12/metabolismo , Células Endoteliales/citología , Endotelio Vascular/citología , Endotelio Vascular/crecimiento & desarrollo , Regulación del Desarrollo de la Expresión Génica , Ratones , Receptores CXCR4/genética , Retina/citología , Retina/crecimiento & desarrollo , Retina/metabolismo , Transducción de Señal , Imagen de Lapso de Tiempo , Venas/citología , Venas/metabolismo , Grabación en Video , Pez Cebra/genética , Pez Cebra/metabolismo , Proteínas de Pez Cebra/genéticaRESUMEN
At sites of angiogenesis, the expression of the key angiogenesis regulator vascular endothelial growth factor (VEGF) and its main receptor, VEGF receptor 2 (VEGFR-2), are strongly upregulated. Whereas the processes controlling VEGF expression are well described, the mechanisms underlying VEGFR-2 upregulation have remained unclear. We found that endothelial VEGFR-2 expression is strongly reduced in the absence of the G protein G13, resulting in an impaired responsiveness to VEGF-A, a phenotype that can be rescued by normalization of VEGFR-2 levels. G13-mediated VEGFR-2 expression involved activation of the small GTPase RhoA and transcription factor NF-κB, the latter acting via a specific binding site at position -84 of the VEGFR-2 promoter. Mice with endothelial cell-specific loss of G13 showed reduced VEGFR-2 expression at sites of angiogenesis and attenuated VEGF effects, resulting in impaired retinal angiogenesis and tumor vascularization. Taken together, we identified G-protein-mediated signaling via G13 as a critical regulator of VEGFR-2 expression during angiogenesis.
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Endotelio/irrigación sanguínea , Subunidades alfa de la Proteína de Unión al GTP G12-G13/metabolismo , Regulación Neoplásica de la Expresión Génica , Neovascularización Patológica/metabolismo , Receptor 2 de Factores de Crecimiento Endotelial Vascular/metabolismo , Alelos , Animales , Línea Celular Tumoral , Endotelio/metabolismo , Subunidades alfa de la Proteína de Unión al GTP G12-G13/genética , Células Endoteliales de la Vena Umbilical Humana , Humanos , Pulmón/metabolismo , Pulmón/patología , Ratones , Ratones Endogámicos C57BL , FN-kappa B/genética , FN-kappa B/metabolismo , Neovascularización Patológica/genética , Regiones Promotoras Genéticas , Proproteína Convertasas/genética , Proproteína Convertasas/metabolismo , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Retina/efectos de los fármacos , Retina/metabolismo , Retina/patología , Vasos Retinianos/metabolismo , Vasos Retinianos/patología , Serina Endopeptidasas/genética , Serina Endopeptidasas/metabolismo , Tamoxifeno/farmacología , Receptor 2 de Factores de Crecimiento Endotelial Vascular/genética , Proteínas de Unión al GTP rho/genética , Proteínas de Unión al GTP rho/metabolismo , Proteína de Unión al GTP rhoARESUMEN
The retina is a powerful experimental system for the analysis of angiogenic blood vessel growth in the postnatal organisms. The three-dimensional architecture of the vessel network and processes as diverse as endothelial cell (EC) proliferation, sprouting, perivascular cell recruitment, vessel remodeling or maturation can be investigated at high resolution. The characterization of physiological and pathological angiogenic processes in mice has been greatly facilitated by inducible and cell type-specific loss-of-function and gain-of-function genetics. In this paper, we provide a detailed protocol for tamoxifen-inducible gene deletion in neonatal mice, as well as for retina dissection, whole-mount immunostaining and the quantitation of EC sprouting and proliferation. These methods have been optimized by our laboratory and yield reliable results. The entire protocol takes approximately 10 d to complete.