RESUMEN
The design of additives showing strong and selective interactions with certain target surfaces is key to crystallization control in applied reactive multicomponent systems. While suitable chemical motifs can be found through semi-empirical trial-and-error procedures, bioinspired selection techniques offer a more rationally driven approach and explore a much larger space of possible combinations in a single assay. Here, phage display screening is used to characterize the surfaces of crystalline gypsum, a mineral of broad relevance for construction applications. Based on next-generation sequencing of phages enriched during the screening process, a triplet of amino acids, DYH, is identified as the main driver for adsorption on the mineral substrate. Furthermore, oligopeptides containing this motif prove to exert their influence in a strictly selective manner during the hydration of cement, where the sulfate reaction (initial setting) is strongly retarded while the silicate reaction (final hardening) remains unaffected. In the final step, these desired additive characteristics are successfully translated from the level of peptides to that of scalable synthetic copolymers. The approach described in this work demonstrates how modern biotechnological methods can be leveraged for the systematic development of efficient crystallization additives for materials science.
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UNLABELLED: Significant evidence implicates α3ß1 integrin in promoting breast cancer tumorigenesis and metastasis-associated cell behaviors in vitro and in vivo. However, the extent to which α3ß1 is actually required for breast cancer metastasis remains to be determined. We used RNA interference to silence α3 integrin expression by approximately 70% in 4T1 murine mammary carcinoma cells, a model of aggressive, metastatic breast cancer. Loss of α3 integrin reduced adhesion, spreading, and proliferation on laminin isoforms, and modestly reduced the growth of orthotopically implanted cells. However, spontaneous metastasis to lung was strikingly curtailed. Experimental lung colonization after tail vein injection revealed a similar loss of metastatic capacity for the α3-silenced (α3si) cells, suggesting that critical, α3-dependent events at the metastatic site could account for much of α3ß1's contribution to metastasis in this model. Reexpressing α3 in the α3si cells reversed the loss of metastatic capacity, and silencing another target, the small GTPase RhoC, had no effect, supporting the specificity of the effect of silencing α3. Parental, α3si, and α3-rescued cells, all secreted abundant laminin α5 (LAMA5), an α3ß1 integrin ligand, suggesting that loss of α3 integrin might disrupt an autocrine loop that could function to sustain metastatic growth. Analysis of human breast cancer cases revealed reduced survival in cases where α3 integrin and LAMA5 are both overexpressed. IMPLICATIONS: α3 integrin or downstream effectors may be potential therapeutic targets in disseminated breast cancers, especially when laminin α5 or other α3 integrin ligands are also over-expressed.
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Neoplasias de la Mama/patología , Integrina alfa3beta1/genética , Laminina/metabolismo , Neoplasias Pulmonares/secundario , Animales , Neoplasias de la Mama/genética , Adhesión Celular/genética , Línea Celular Tumoral , Movimiento Celular/genética , Proliferación Celular , Transformación Celular Neoplásica/genética , Femenino , Humanos , Integrina alfa3beta1/biosíntesis , Laminina/biosíntesis , Pulmón/patología , Neoplasias Pulmonares/patología , Ratones , Ratones Endogámicos BALB C , Invasividad Neoplásica/genética , Trasplante de Neoplasias , Isoformas de Proteínas , Interferencia de ARN , ARN Mensajero/biosíntesis , ARN Interferente Pequeño , Sobrevida , Proteínas de Unión al GTP rho/genética , Proteína rhoC de Unión a GTPRESUMEN
Integrin α3ß1 potently promotes cell motility on its ligands, laminin-332 and laminin-511, and this may help to explain why α3ß1 has repeatedly been linked to breast carcinoma progression and metastasis. The pro-migratory functions of α3ß1 depend strongly on lateral interactions with cell surface tetraspanin proteins. Tetraspanin CD151 interacts directly with the α3 integrin subunit and links α3ß1 integrin to other tetraspanins, including CD9 and CD81. Loss of CD151 disrupts α3ß1 association with other tetraspanins and impairs α3ß1-dependent motility. However, the extent to which tetraspanins other than CD151 are required for specific α3ß1 functions is unclear. To begin to clarify which aspects of α3ß1 function require which tetraspanins, we created breast carcinoma cells depleted of both CD9 and CD81 by RNA interference. Silencing both of these closely related tetraspanins was required to uncover their contributions to α3ß1 function. We then directly compared our CD9/CD81-silenced cells to CD151-silenced cells. Both CD9/CD81-silenced cells and CD151-silenced cells showed delayed α3ß1-dependent cell spreading on laminin-332. Surprisingly, however, once fully spread, CD9/CD81-silenced cells, but not CD151-silenced cells, displayed impaired α3ß1-dependent directed motility and altered front-rear cell morphology. Also unexpectedly, the CD9/CD81 complex, but not CD151, was required to promote α3ß1 association with PKCα in breast carcinoma cells, and a PKC inhibitor mimicked aspects of the CD9/CD81-silenced cell motility defect. Our data reveal overlapping, but surprisingly distinct contributions of specific tetraspanins to α3ß1 integrin function. Importantly, some of CD9/CD81's α3ß1 regulatory functions may not require CD9/CD81 to be physically linked to α3ß1 by CD151.
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Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Integrina alfa3beta1/metabolismo , Tetraspanina 24/metabolismo , Tetraspanina 28/metabolismo , Tetraspanina 29/metabolismo , Animales , Adhesión Celular/efectos de los fármacos , Moléculas de Adhesión Celular/farmacología , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Polaridad Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Forma de la Célula/efectos de los fármacos , Femenino , Citometría de Flujo , Silenciador del Gen/efectos de los fármacos , Humanos , Modelos Biológicos , Unión Proteica/efectos de los fármacos , Proteína Quinasa C-alfa/metabolismo , Ratas , KalininaRESUMEN
Mouse Xin-alpha (mXin-alpha) encodes a Xin repeat-containing, actin-binding protein localized to the intercalated disc (ICD). Ablation of mXin-alpha progressively leads to disrupted ICD structure, cardiac hypertrophy and cardiomyopathy with conduction defects during adulthood. Such conduction defects could be due to ICD structural defects and/or cell electrophysiological property changes. Here, we showed that despite the normal ICD structure, juvenile mXina-null cardiomyocytes (from 3~4-week-old mice) exhibited a significant reduction in the transient outward K+ current (ITO), similar to adult mutant cells. Juvenile but not adult mutant cardiomyocytes also had a significant reduction in the delayed rectifier K+ current. In contrast, the mutant adult ventricular myocytes had a significant reduction in the inward rectifier K+ current (IK1) on hyperpolarization. These together could account for the prolongation of action potential duration (APD) and the ease of developing early afterdepolarization observed in juvenile mXin-alpha-null cells. Interestingly, juvenile mXin-alpha-null cardiomyocytes had a notable decrease in the amplitude of intracellular Ca2+ transient and no change in the L-type Ca2+ current, suggesting that the prolonged APD did not promote an increase in intracellular Ca2+ for cardiac hypertrophy. Juvenile mXin-alpha-null ventricles had reduced levels of membrane-associated Kv channel interacting protein 2, an auxiliary subunit of ITO, and filamin, an actin cross-linking protein. We further showed that mXin-alpha interacted with both proteins, providing a novel mechanism for ITO surface expression.
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Ventrículos Cardíacos/metabolismo , Proteínas Musculares/metabolismo , Animales , Secuencia de Bases , Células Cultivadas , Cartilla de ADN , Ventrículos Cardíacos/citología , Ventrículos Cardíacos/ultraestructura , Masculino , Ratones , Ratones Endogámicos C57BL , Microscopía Electrónica de Transmisión , Proteínas Musculares/fisiología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Técnicas del Sistema de Dos HíbridosRESUMEN
RATIONALE: The Xin repeat-containing proteins mXinalpha and mXinbeta localize to the intercalated disc of mouse heart and are implicated in cardiac development and function. The mXinalpha directly interacts with beta-catenin, p120-catenin, and actin filaments. Ablation of mXinalpha results in adult late-onset cardiomyopathy with conduction defects. An upregulation of the mXinbeta in mXinalpha-deficient hearts suggests a partial compensation. OBJECTIVE: The essential roles of mXinbeta in cardiac development and intercalated disc maturation were investigated. METHODS AND RESULTS: Ablation of mXinbeta led to abnormal heart shape, ventricular septal defects, severe growth retardation, and postnatal lethality with no upregulation of the mXinalpha. Postnatal upregulation of mXinbeta in wild-type hearts, as well as altered apoptosis and proliferation in mXinbeta-null hearts, suggests that mXinbeta is required for postnatal heart remodeling. The mXinbeta-null hearts exhibited a misorganized myocardium as detected by histological and electron microscopic studies and an impaired diastolic function, as suggested by echocardiography and a delay in switching off the slow skeletal troponin I. Loss of mXinbeta resulted in the failure of forming mature intercalated discs and the mislocalization of mXinalpha and N-cadherin. The mXinbeta-null hearts showed upregulation of active Stat3 (signal transducer and activator of transcription 3) and downregulation of the activities of Rac1, insulin-like growth factor 1 receptor, protein kinase B, and extracellular signal-regulated kinases 1 and 2. CONCLUSIONS: These findings identify not only an essential role of mXinbeta in the intercalated disc maturation but also mechanisms of mXinbeta modulating N-cadherin-mediated adhesion signaling and its crosstalk signaling for postnatal heart growth and animal survival.
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Proteínas de Unión al ADN/metabolismo , Corazón/crecimiento & desarrollo , Corazón/fisiopatología , Proteínas Nucleares/metabolismo , Animales , Animales Recién Nacidos , Proliferación Celular , Supervivencia Celular , Proteínas del Citoesqueleto , Proteínas de Unión al ADN/deficiencia , Proteínas con Dominio LIM , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Proteínas Nucleares/deficienciaRESUMEN
The development of lameness is influenced by a number of different factors (housing, management, human-animal relationship and animal-related parameters). The aim of this study was to investigate the effects of the complex interactions of these aspects and to search for the relative importance of single factors. In 80 dairy herds of Austrian Simmental cows housed in cubicle loose housing in Upper and Lower Austria, risk factors for lameness, selected from the four factor groups housing, management, human-animal relationship and animal-related variables, were investigated during one farm visit in the autumn and winter months. To assess their relative importance, a multivariable analysis (regression trees) was calculated. The most important risk factor for lameness was the lying surface: straw bedding of at least 2 cm thickness or cow-comfort mats were associated with a lower percentage of lame cows. In case of insufficient quality of the lying surface, the next important parameter identified was the position of the neck rail: a neck rail diagonal greater than 1.94 m was associated with a lower percentage of lame cows. By contrast, on farms with high-quality lying surfaces, lameness prevalence was lower when at least parts of the alleys were constructed with solid floor and not slatted. Further variables associated with a low prevalence of lameness were a longer time span between calving and separation of the calf from the dam, the existence of an outside run, a lower percentage of fat cows, a greater space allowance, more cubicles than animals and a lower kerb height. In addition, further management factors such as the way in which heifers are integrated into the herd or management decisions taking into account the cows' welfare were related to less lameness. Human-animal relationship variables such as, for example, the behaviour and attitude of the stockpeople were explaining variables. In sum, important risk factors were found in all factor groups. Therefore it is necessary to optimise all those different aspects mentioned above to reduce the risk of lameness.
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Enfermedades de los Bovinos/prevención & control , Vivienda para Animales , Cojera Animal/prevención & control , Bienestar del Animal , Animales , Austria/epidemiología , Bovinos , Enfermedades de los Bovinos/epidemiología , Industria Lechera , Femenino , Pisos y Cubiertas de Piso , Cojera Animal/epidemiología , Prevalencia , Factores de RiesgoRESUMEN
The vitamin A derivative retinoic acid (RA) regulates the transcription of about a 6th of the human genome. Compelling evidence indicates a role of RA in cognitive activities, but its integration with the molecular mechanisms of higher brain functions is not known. Here we describe the properties of RA signaling in the mouse, which point to unknown means through which RA actions are modified and reinforced at selected brain sites. The locations of RA signaling for the developing dorsal forebrain undergo slow, gradual changes over the life cycle except for two brief periods of accelerated shifts, which coincide with periods of enhanced developmental vulnerability. In the functional cerebral cortex, RA signaling delineates regions with immature, plastic neuronal characteristics, within which the expression of hundreds of genes is differentially regulated. Many of these are involved in neuronal ligand-receptor interactions and signaling cascades for activity dependent gene expression. We propose that RA functions in the brain by contributing topographical information and life cycle changes to combinatorial transcriptional mechanisms and that in the postnatal cortex RA signaling designates domains of modifiable neuronal circuitry.
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Encéfalo/fisiología , Cognición/fisiología , Transducción de Señal/fisiología , Tretinoina/metabolismo , Animales , Regulación del Desarrollo de la Expresión Génica , HumanosRESUMEN
Targeted deletion of mXinalpha results in cardiac hypertrophy and cardiomyopathy with conduction defects (Gustafson-Wagner, E., Sinn, H. W., Chen, Y.-L., Wang, D.-Z., Reiter, R. S., Lin, J. L.-C., Yang, B., Williamson, R. A., Chen, J. N., Lin, C.-I., and Lin, J. J.-C. (2007) Am. J. Physiol. 293, H2680-H2692). To understand the underlying mechanisms leading to such cardiac defects, the functional domains of mXinalpha and its interacting proteins were investigated. Interaction studies using co-immunoprecipitation, pull-down, and yeast two-hybrid assays revealed that mXinalpha directly interacts with beta-catenin. The beta-catenin-binding site on mXinalpha was mapped to amino acids 535-636, which overlaps with the known actin-binding domains composed of the Xin repeats. The overlapping nature of these domains provides insight into the molecular mechanism for mXinalpha localization and function. Purified recombinant glutathione S-transferase- or His-tagged mXinalpha proteins are capable of binding and bundling actin filaments, as determined by co-sedimentation and electron microscopic studies. The binding to actin was saturated at an approximate stoichiometry of nine actin monomers to one mXinalpha. A stronger interaction was observed between mXinalpha C-terminal deletion and actin as compared with the interaction between full-length mXinalpha and actin. Furthermore, force expression of green fluorescent protein fused to an mXinalpha C-terminal deletion in cultured cells showed greater stress fiber localization compared with force-expressed GFP-mXinalpha. These results suggest a model whereby the C terminus of mXinalpha may prevent the full-length molecule from binding to actin, until the beta-catenin-binding domain is occupied by beta-catenin. The binding of mXinalpha to beta-catenin at the adherens junction would then facilitate actin binding. In support of this model, we found that the actin binding and bundling activity of mXinalpha was enhanced in the presence of beta-catenin.
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Citoesqueleto de Actina/metabolismo , Actinas/metabolismo , Uniones Adherentes/metabolismo , Proteínas de Unión al ADN/metabolismo , Proteínas Nucleares/metabolismo , beta Catenina/metabolismo , Citoesqueleto de Actina/genética , Citoesqueleto de Actina/ultraestructura , Actinas/genética , Uniones Adherentes/genética , Uniones Adherentes/patología , Secuencia de Aminoácidos/genética , Animales , Células CHO , Cardiomiopatías/genética , Cardiomiopatías/metabolismo , Cardiomiopatías/patología , Cricetinae , Cricetulus , Proteínas de Unión al ADN/genética , Sistema de Conducción Cardíaco/metabolismo , Sistema de Conducción Cardíaco/patología , Hipertrofia/genética , Hipertrofia/metabolismo , Hipertrofia/patología , Ratones , Modelos Biológicos , Proteínas Nucleares/genética , Mapeo Peptídico , Unión Proteica/genética , Estructura Terciaria de Proteína , Conejos , Eliminación de Secuencia , Técnicas del Sistema de Dos Híbridos , beta Catenina/genéticaRESUMEN
The intercalated disk protein Xin was originally discovered in chicken striated muscle and implicated in cardiac morphogenesis. In the mouse, there are two homologous genes, mXinalpha and mXinbeta. The human homolog of mXinalpha, Cmya1, maps to chromosomal region 3p21.2-21.3, near a dilated cardiomyopathy with conduction defect-2 locus. Here we report that mXinalpha-null mouse hearts are hypertrophied and exhibit fibrosis, indicative of cardiomyopathy. A significant upregulation of mXinbeta likely provides partial compensation and accounts for the viability of the mXinalpha-null mice. Ultrastructural studies of mXinalpha-null mouse hearts reveal intercalated disk disruption and myofilament disarray. In mXinalpha-null mice, there is a significant decrease in the expression level of p120-catenin, beta-catenin, N-cadherin, and desmoplakin, which could compromise the integrity of the intercalated disks and functionally weaken adhesion, leading to cardiac defects. Additionally, altered localization and decreased expression of connexin 43 are observed in the mXinalpha-null mouse heart, which, together with previously observed abnormal electrophysiological properties of mXinalpha-deficient mouse ventricular myocytes, could potentially lead to conduction defects. Indeed, ECG recordings on isolated, perfused hearts (Langendorff preparations) show a significantly prolonged QT interval in mXinalpha-deficient hearts. Thus mXinalpha functions in regulating the hypertrophic response and maintaining the structural integrity of the intercalated disk in normal mice, likely through its association with adherens junctional components and actin cytoskeleton. The mXinalpha-knockout mouse line provides a novel model of cardiac hypertrophy and cardiomyopathy with conduction defects.
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Arritmias Cardíacas/fisiopatología , Cardiomegalia/fisiopatología , Cardiomiopatías/fisiopatología , Proteínas de Unión al ADN/metabolismo , Sistema de Conducción Cardíaco/fisiopatología , Proteínas Nucleares/metabolismo , Sarcolema/metabolismo , Animales , Arritmias Cardíacas/patología , Cardiomegalia/patología , Cardiomiopatías/patología , Sistema de Conducción Cardíaco/patología , Ratones , Ratones Noqueados , Sarcolema/patologíaRESUMEN
To understand how cardiac gene expression is regulated, the identification and characterization of cis-regulatory elements and their trans-acting factors by gel mobility shift assay (GMSA) or gel retardation assay are essential and common steps. In addition to providing a general protocol for GMSA, this chapter describes some applications of this assay to characterize cardiac-specific and ubiquitous trans-acting factors bound to regulatory elements [novel TCTG(G/C) direct repeat and A/T-rich region] of the rat cardiac troponin T promoter. In GMSA, the specificity of the binding of trans-acting factor to labeled DNA probe should be verified by the addition of unlabeled probe in the reaction mixture. The migratory property of DNA-protein complexes formed by protein extracts prepared from different tissues can be compared to determine the tissue specificity of trans-acting factors. GMSA, coupled with specific antibody to trans-acting factor (antibody supershift assay), is used to identify proteins present in the DNA-protein complex. The gel-shift competition assay with an unlabeled probe containing a slightly different sequence is a powerful technique used to assess the sequence specificity and relative binding affinity of a DNA-protein interaction. GMSA with SDS-PAGE fractionated proteins allows for the determination of the apparent molecular mass of bound trans-acting factor.
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Ensayo de Cambio de Movilidad Electroforética/métodos , Miocardio/metabolismo , Regiones Promotoras Genéticas , Elementos Reguladores de la Transcripción/genética , Factores de Transcripción/genética , Animales , Secuencia de Bases , Células Cultivadas , Electroforesis en Gel de Poliacrilamida , Mucosa Gástrica/metabolismo , Hígado/metabolismo , Datos de Secuencia Molecular , Músculo Esquelético/metabolismo , Unión Proteica , Ratas , Homología de Secuencia de Ácido Nucleico , Troponina T/genéticaRESUMEN
Retinoic acid is well recognized to promote neuronal differentiation in the embryonic nervous system, but how it influences the postnatal cerebral cortex remains largely unknown. The domain of highest retinoic acid actions in the cortex of the mouse constricts postnatally to a narrow band that includes the dorsal visual stream and the attentional and executive networks. This band of cortex, which is distinguished by the retinoic acid-synthesizing enzyme RALDH3, exhibits signs of delayed maturation and enhanced plasticity compared to the surrounding cortex, as indicated by suppression of parvalbumin, neurofilament, cytochrome oxidase and perineuronal net maturation, and persistence of the embryonic, polysialated form of the neural cell-adhesion molecule PSA-NCAM. During the first postnatal week, the RALDH3-expressing territory translocates in the caudal cortex from the medial limbic lobe to the adjacent neocortex. This topographical shift requires the neurotrophin NT-3 because in mice lacking neuronal NT-3 the RALDH3 enzyme maintains its early postnatal pattern up to adulthood. In the NT-3-null mutants, expression of the markers, whose topography colocalizes with RALDH3 in the normal cortex, matches the abnormal RALDH3 pattern. This indicates that the uneven retinoic acid distribution serves a role in patterning the maturation and to some extent function of the normal postnatal cerebral cortex.
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Aldehído Oxidorreductasas/metabolismo , Corteza Cerebral/crecimiento & desarrollo , Corteza Cerebral/metabolismo , Plasticidad Neuronal/fisiología , Neuronas/metabolismo , Tretinoina/metabolismo , Aldehído Oxidorreductasas/genética , Animales , Animales Recién Nacidos , Biomarcadores/metabolismo , Diferenciación Celular/fisiología , Corteza Cerebral/citología , Complejo IV de Transporte de Electrones/metabolismo , Regulación del Desarrollo de la Expresión Génica/fisiología , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Molécula L1 de Adhesión de Célula Nerviosa/metabolismo , Vías Nerviosas/citología , Vías Nerviosas/crecimiento & desarrollo , Vías Nerviosas/metabolismo , Proteínas de Neurofilamentos/metabolismo , Neuronas/citología , Neurotrofina 3/genética , Parvalbúminas/metabolismo , Transporte de Proteínas/fisiología , Retinal-Deshidrogenasa , Ácidos Siálicos/metabolismoRESUMEN
Vitamin A is known to be critical for the beginning of eye development as well as for photoreception in the functional retina. Hardly anything, however, is known about whether retinoic acid (RA)-regulated gene expression also plays a role in the long intervening period, during which the neurobiological retinal structure takes shape. The eye contains a highly intricate architecture of RA-synthesizing (RALDH) and degrading (CYP26) enzymes. Whereas the RALDHs are integrated in the early molecular mechanisms through which the dorso-ventral retina organization is established, the CYP26 enzymes are not necessary for this process and no molecular targets that match their retinal expression pattern have yet been identified. In this article we describe that CYP26 expression in the mouse is most distinctive during later stages of retina formation. Throughout development CYP26A1 degrades RA in a horizontal region that extends across the retina, but during later embryonic and postnatal retina maturation this function is reinforced by another enzyme, CYP26C1. RA applications at this stage do not affect the RALDHs but cause differential changes in CYP26 expression: Cyp26a1 is up-regulated, but more rapidly by 9-cis than all-trans RA, Cyp26c1 is down-regulated, and Cyp26b1, which is undetectable in the normal mouse retina, is strongly activated in retinal ganglion cells. The dynamic regulation in RA-difference patterns by the CYP26 enzymes may set up spatial constellations for expression of genes involved in formation of retinal specializations for higher acuity vision, which are known to form over a prolonged period late in retina development.
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Sistema Enzimático del Citocromo P-450/metabolismo , Ojo/embriología , Retinoides/fisiología , Visión Ocular/fisiología , Aldehído Oxidorreductasas/metabolismo , Animales , Regulación del Desarrollo de la Expresión Génica , Humanos , Ratones , Ácido Retinoico 4-HidroxilasaRESUMEN
Xin was first cloned using differential mRNA display from the developing chicken heart. Chick Xin (cXin) participates in a BMP-Nkx2.5-MEF2C pathway to regulating cardiac morphogenesis. Through subsequent EST database searches and cDNA cloning, two mouse Xin genes, mXinα and mXinß were identified and cloned. The human homologue of mXinα (named Cmya1) was mapped to chromosome 3p21.2-p21.3 by radiation hybrid analysis and recently to 3p22.2 by DNA sequencing, which is near the loci for a dilated cardiomyopathy with conduction defect-2 and arrhythmogenic right ventricular dysplasia-5. The predicted human homologue of mXinß (named Cmya3) was mapped to chromosome 2q24.3 by DNA sequencing. Predicted Xin proteins all contain a novel 16-amino acid repeating unit (Xin repeat), a putative DNA binding domain and nuclear localization signal, as well as a proline-rich region. All three Xin genes from chick and mouse have a similar tissue expression profile, which is restricted to striated muscle. The expression of mXinα in Nkx2.5 or MEF2C knockout mouse embryos was drastically reduced, suggesting that mXinα is a downstream target of the Nkx2.5 and MEF2C transcription factors. On the other hand, the expression of mXin was up-regulated when mice were subjected to pressure overload-induced cardiac hypertrophy. Xin protein co-localizes with N-cadherin and ß-catenin throughout mouse embryogenesis and into adulthood. Furthermore, mXinα appears to interact directly with ß-catenin. The Xin repeats bind to actin filaments and may also organize microfilaments into networks. These results may suggest that Xin acts by integrating adhesion, by organizing actin filament arrangement at the insertion sites, and by regulating Wnt/ß-catenin-and N-cadherin-mediated signaling pathways required for cardiac development and cardiac function.
RESUMEN
BACKGROUND: A normal supply of vitamin A, which regulates gene expression through its active form retinoic acid, is required by many organs; both excess and deficiency can be teratogenic. Very little is known about the role of retinoic acid in maturation of the mammalian forebrain. METHODS: As retinoic acid cannot be visualized directly, we mapped its actions in the forebrain with indirect morphologic methods and by applying retinoic acid overdoses to early postnatal mice. RESULTS: During this time, the morphologic indicators of retinoic acid actions are localized mainly in the limbic system and they undergo rapid changes. Retinoic acid overdoses can cause lasting behavioral abnormalities that point to disrupted limbic functions. In the anterior cingulate cortex, inhibitory interneurons are affected, and in the hippocampus, primarily the dentate gyrus is abnormal. CONCLUSIONS: Retinoic acid is involved in functional maturation of limbic regions of the forebrain with a critical stage early postnatally in mice, when their brains are particularly vulnerable to vitamin A perturbations. This developmental time in mice compares with the second trimester of gestation in humans, a stage when in genetically predisposed individuals the corresponding brain regions are known to pass through a period of increased susceptibility to environmental disturbances.
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Encéfalo/crecimiento & desarrollo , Período Crítico Psicológico , Tretinoina/fisiología , Factores de Edad , Aldehído Oxidorreductasas/metabolismo , Animales , Animales Recién Nacidos , Conducta Animal/efectos de los fármacos , Conducta Animal/fisiología , Encéfalo/anatomía & histología , Encéfalo/metabolismo , Calbindinas , Recuento de Células/métodos , Relación Dosis-Respuesta a Droga , Embrión de Mamíferos , Proteína Ácida Fibrilar de la Glía/metabolismo , Hipercinesia/inducido químicamente , Inmunohistoquímica/métodos , Dosificación Letal Mediana , Ratones , Ratones Mutantes , Actividad Motora/efectos de los fármacos , Actividad Motora/fisiología , Molécula L1 de Adhesión de Célula Nerviosa/metabolismo , Parvalbúminas/metabolismo , Receptores de Ácido Retinoico/genética , Retinal-Deshidrogenasa , Rotación , Proteína G de Unión al Calcio S100/metabolismo , Ácidos Siálicos/metabolismo , Grabación en Video/métodosRESUMEN
The aim of the present study in cats was to investigate the potential effects of a calcium carbonate and chitosan supplement on blood parameters in aged cats with moderate chronic renal failure and on the mineral balance in adult healthy cats. For the trials, 10 neutered cats 2-4 years of age were fed for 21 days and six neutered cats (2 male and 4 female), 14 years of age, with elevated urea and phosphorus level in the plasma were fed for 35 days with a supplement. The apparent digestibility of phosphorus was (p < 0.05) reduced in the treatment period. Plasma urea inorganic phosphate decreased significantly (p < 0.05) in the old cats after 35 days of treatment. The treatment had a significant effect on the phosphorus, gross energy, dry matter, crude ash, crude fiber and crude protein digestibility in adult healthy cats. The practical implication could be an alternative treatment option for cats refusing to ingest veterinary renal diets.
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Calcio de la Dieta/administración & dosificación , Calcio/metabolismo , Gatos/metabolismo , Quelantes/administración & dosificación , Quitosano/administración & dosificación , Fósforo/metabolismo , Envejecimiento/fisiología , Alimentación Animal , Animales , Nitrógeno de la Urea Sanguínea , Carbonato de Calcio/administración & dosificación , Enfermedades de los Gatos/tratamiento farmacológico , Enfermedades de los Gatos/metabolismo , Quelantes/metabolismo , Suplementos Dietéticos , Digestión , Femenino , Fallo Renal Crónico/tratamiento farmacológico , Fallo Renal Crónico/metabolismo , Fallo Renal Crónico/veterinaria , Masculino , Fosfatos/sangreRESUMEN
As retinoic acid (RA) is known to regulate the expression of many neuronal proteins, it is likely to influence overall development and function of the brain; few particulars, however, are available about its role in neurobiological contexts due mainly to problems in RA detection. To ask whether the function of RA in the rostral brain is concentrated in particular neurobiological systems, we compared sites of RA synthesis and actions, as detected by RA signaling in reporter mice, for embryonic and adult ages. We found that most sites of RA actions in the forebrain do not colocalize with RA synthesis, consistent with a dominant RA supply by diffusion and the circulation. The changing RA patterns distinguish preferentially two complex functional schemes. (1) Within the visual system when the first optic axons grow toward their targets, RA signaling delineates the topographical adjustment of the retinal map, which is encoded in the coordinates of the visual world, to central visual maps, which are formed in the segmental brain coordinates. (2) The second scheme begins early in forebrain morphogenesis as a distinction of the dorsal telencephalon. With progressing development, and in the adult, the RA patterns then focus on widely distributed structures, most of which belong to the limbic system. These are sites in which emotional perception is combined with higher cognitive processes and in which normal function requires ongoing remodeling of synaptic connections, indicating that the developmental role of RA in promotion of neuronal differentiation programs continues in the adult brain for highly flexible neural circuits. J. Comp. Neurol. 470:297-316, 2004.
Asunto(s)
Sistema Límbico/metabolismo , Transducción de Señal/fisiología , Telencéfalo/metabolismo , Tretinoina/metabolismo , Vías Visuales/metabolismo , Animales , Encéfalo/embriología , Encéfalo/crecimiento & desarrollo , Encéfalo/metabolismo , Células COS , Chlorocebus aethiops , Femenino , Genes Reporteros/fisiología , Sistema Límbico/embriología , Sistema Límbico/crecimiento & desarrollo , Ratones , Ratones Endogámicos C57BL , Embarazo , Telencéfalo/embriología , Telencéfalo/crecimiento & desarrollo , Vías Visuales/embriología , Vías Visuales/crecimiento & desarrolloRESUMEN
Retinoic acid (RA) affects development and function of the brain, but little is known about how much is made locally and where it is distributed. To identify RA-sensitive neural processes, we mapped the RA-synthesizing retinaldehyde dehydrogenases (RALDHs) during postnatal brain formation of the mouse. High and stable RALDH expressions mark the basal ganglia, olfactory bulbs, hippocampus and auditory afferents as major sites of RA actions in the functional brain. During the early postnatal period, transient and very high RALDH3 expressions distinguish two developmental events: (i) the colonization of the nucleus accumbens and the olfactory bulbs by neuronal precursors and (ii) the maturation of selected parts of the cerebral cortex. In the cortex, RALDH3 is transiently activated in postmigratory layer II/III neurons during formation of their dendritic arbors and it is transported in their axons across the corpus callosum. RALDH3-expressing cortical regions include most of the limbic lobe, with strongest expression in the anterior cingulate cortex, medial and lateral secondary visual cortices, auditory cortical areas, the secondary motor cortex and some association areas. The transient cortical expression points to a brief RA-critical period during differentiation of the cortical network that serves in the coordination of sensory-motor activity with emotional and recently learned information.