Novel role of p73 as a regulator of developmental angiogenesis: implication for cancer therapy

[EN] Information regarding the role of p73 in the regulation of angiogenesis has been incomplete and quite controversial. Remarkably, several groups, including ours, have recently demonstrated that TP73 plays a fundamental role in angiogenesis regulation and that differential expression of TP73 could have important consequences in tumor angiogenesis. Here, we discuss a possible model for p73 function in the regulation of developmental angiogenesis and tumor angiogenesisS

p73 as a Tissue Architect

Sec. Molecular and Cellular Pathology[EN] The TP73 gene belongs to the p53 family comprised by p53, p63, and p73. In response to physiological and pathological signals these transcription factors regulate multiple molecular pathways which merge in an ensemble of interconnected networks, in which the control of cell proliferation and cell death occupies a prominent position. However, the complex phenotype of the Trp73 deficient mice has revealed that the biological relevance of this gene does not exclusively rely on its growth suppression effects, but it is also intertwined with other fundamental roles governing different aspects of tissue physiology. p73 function is essential for the organization and homeostasis of different complex microenvironments, like the neurogenic niche, which supports the neural progenitor cells and the ependyma, the male and female reproductive organs, the respiratory epithelium or the vascular network. We propose that all these, apparently unrelated, developmental roles, have a common denominator: p73 function as a tissue architect. Tissue architecture is defined by the nature and the integrity of its cellular and extracellular compartments, and it is based on proper adhesive cell-cell and cell-extracellular matrix interactions as well as the establishment of cellular polarity. In this work, we will review the current understanding of p73 role as a neurogenic niche architect through the regulation of cell adhesion, cytoskeleton dynamics and Planar Cell Polarity, and give a general overview of TAp73 as a hub modulator of these functions, whose alteration could impinge in many of the Trp73–/– phenotypesSIThis work was supported by Grant PID2019-105169RB-I00 from Spanish Ministerio de Ciencia e Innovación cofinanced by FEDER funds (to MCM). LM-A was a holder of a predoctoral scholarship from the Asociación Española contra el Cáncer (AECC) and was funded by a postdoctoral contract from Junta de Castilla y León

Modificación genética en cerdos destinados a xenotrasplante

Sección: Poniendo en claro[ES] La escasez de órganos humanos para trasplante ha propiciado la búsqueda de otras alternativas, como la posibilidad de utilizar animales como donantes, lo que se conoce como xenotrasplante. El cerdo se ha convertido en la especie donante más prometedora tanto por su similitud anatómica y fisiológica con el ser humano, como por la disponibilidad de metodologías de modificación genética, que han permitido la obtención de modelos porcinos que permiten hacer frente a los riesgos del xenotrasplante. Estos riesgos están asociados con el rechazo inmunológico, la desregulación de la coagulación y la presencia de retrovirus endógenos porcinos. Aunque los resultados de los ensayos preclínicos en primates varían considerablemente, alcanzando diferentes tiempos de supervivencia en función del órgano trasplantado, la inactivación del gen que codifica el antígeno α-Gal ha resultado imprescindible para superar el rechazo hiperagudo, que es la primera y más drástica barrera inmunológica. Los hitos que se han logrado en los últimos años, incluyendo las pruebas clínicas recientes con seres humanos a los que se han realizado trasplantes de riñón o corazón de cerdos modificados genéticamente, acercan un paso más el traslado de los xenotrasplantes a la práctica clínic

Aplicaciones del sistema CRISPR-Cas9 a la modificación genética en animales domésticos

Los editores genéticos, especialmente el sistema CRISPR-Cas9, han supuesto un gran avance para la modificación genética de animales. En el presente artículo, se realiza una revisión de la metodología específica en animales domésticos y sus aplicaciones en Producción Animal y Biomedicina. La parte general sobre la edición genética y el sistema CRISPR-Cas9, ha sido desarrollada en el artículo anterior centrado en las plantas. A pesar de su reciente implementación en la década actual, esta herramienta ha demostrado ya su eficacia en aspectos tan diversos como la resistencia a enfermedades, la mejora de productos de origen animal, o también el uso de animales como biorreactores, modelos de enfermedades humanas o fuente de órganos para xenotrasplante. A pesar de aspectos técnicos que aún deben ser abordados, el sistema CRISPR-Cas9 con su elevada eficiencia y diseño rápido, sencillo y económico, destaca entre las técnicas de modificación genética. Esto lo convierte, en este contexto, en la metodología con mejores perspectivas futuras, no solo para el mundo animal sino también en el ámbito de la salud human

Células troncales y reprogramación celular

A partir de diferentes estadios del desarrollo embrionario murino, es posible establecer in vitro cultivos de células troncales que presentan dos rasgos distintivos: su capacidad para proliferar indefinidamente, dando lugar a nuevas células troncales (auto-renovación), y su capacidad de diferenciación a todos los tipos celulares que forman el organismo adulto (pluripotencia). Durante décadas, el tránsito del estado pluripotente al estado de diferenciación terminal fue considerado irreversible; sin embargo, en la actualidad es posible revertir este proceso e inducir la pluripotencia en células somáticas mediante la expresión de factores de transcripción que regulan la identidad de las células troncales embrionarias. Este proceso, denominado reprogramación celular, da lugar a la generación de células troncales pluripotentes inducidas (iPSCs), que presentan características moleculares y funcionales similares a las de células troncales embrionarias (ESCs). Por ello, las células reprogramadas son una valiosa herramienta en Biomedicina, y están siendo empleadas para modelar enfermedades humanas o para la búsqueda de nuevos tratamientos en patologías que no responden a los enfoques clínicos tradicionale

The Trp73 Mutant Mice: A Ciliopathy Model That Uncouples Ciliogenesis From Planar Cell Polarity

Sec. Genetics of Common and Rare Diseases[EN] p73 transcription factor belongs to one of the most important gene families in vertebrate biology, the p53-family. Trp73 gene, like the other family members, generates multiple isoforms named TA and DNp73, with different and, sometimes, antagonist functions. Although p73 shares many biological functions with p53, it also plays distinct roles during development. Trp73 null mice (p73KO from now on) show multiple phenotypes as gastrointestinal and cranial hemorrhages, rhinitis and severe central nervous system defects. Several groups, including ours, have revisited the apparently unrelated phenotypes observed in total p73KO and revealed a novel p73 function in the organization of ciliated epithelia in brain and trachea, but also an essential role as regulator of ependymal planar cell polarity. Unlike p73KO or TAp73KO mice, tumor-prone Trp53−/− mice (p53KO) do not present ependymal ciliary or planar cell polarity defects, indicating that regulation of ciliogenesis and PCP is a p73-specific function. Thus, loss of ciliary biogenesis and epithelial organization might be a common underlying cause of the diverse p73KO-phenotypes, highlighting Trp73 role as an architect of the epithelial tissue. In this review we would like to discuss the data regarding p73 role as regulator of ependymal cell ciliogenesis and PCP, supporting the view of the Trp73-mutant mice as a model that uncouples ciliogenesis from PCP and a possible model of human congenital hydrocephalusSIThis work was supported by Grants SAF2015-71381-R from Spanish Ministerio de Economía y Competitividad co-financed by FEDER funds (to MCM) and LE021P17 from Junta de Castilla y Leon. JV-F and SF-A are holders of predoctoral fellowships from the Junta de Castilla y León. LM-A is supported by a pre-doctoral scholarship from the Asociación Española contra el Cáncer (AECC

Transgénesis en animales de granja

La transgénesis en animales de granja ha experimentado una importante evolución desde sus inicios en la década de los años 80. La eficiencia de las técnicas ha aumentado considerablemente y, a las primeras experiencias llevadas a cabo mediante microinyección pronuclear en el cigoto, le han seguido otras metodologías como la transferencia nuclear de células somáticas, que ha tenido particular importancia en estas especies domésticas. Además, en los últimos años, se han desarrollado herramientas de edición del genoma que permiten una alta especificidad en la modificación genética. Entre las numerosas aplicaciones de los animales transgénicos, se encuentra la producción de proteínas de uso terapéutico humano. También, cabe destacar las investigaciones con objeto de generar animales modificados genéticamente para ser utilizados como modelos de enfermedades humanas, o bien destinados a proporcionar órganos para xenotrasplante. Además, en el ámbito estricto de la Producción Animal se está explorando la utilización de la transgénesis para incrementar la resistencia de los animales a enfermedades o mejorar la cantidad y calidad de sus producto

Deciphering the Nature of Trp73 Isoforms in Mouse Embryonic Stem Cell Models: Generation of Isoform-Specific Deficient Cell Lines Using the CRISPR/Cas9 Gene Editing System

This article belongs to the Special Issue The Isoforms of the p53 Gene Family and Their Role in Cancer and Aging：Selection Papers from International p53/p63/p73 Isoforms Workshop[EN] The p53 family has been widely studied for its role in various physiological and pathological processes. Imbalance of p53 family proteins may contribute to developmental abnormalities and pathologies in humans. This family exerts its functions through a profusion of isoforms that are generated by different promoter usage and alternative splicing in a cell type dependent manner. In particular, the Trp73 gene gives rise to TA and DN-p73 isoforms that confer p73 a dual nature. The biological relevance of p73 does not only rely on its tumor suppression effects, but on its pivotal role in several developmental processes. Therefore, the generation of cellular models that allow the study of the individual isoforms in a physiological context is of great biomedical relevance. We generated specific TA and DN-p73-deficient mouse embryonic stem cell lines using the CRISPR/Cas9 gene editing system and validated them as physiological bona fide p73-isoform knockout models. Global gene expression analysis revealed isoform-specific alterations of distinctive transcriptional networks. Elimination of TA or DN-p73 is compatible with pluripotency but prompts naïve pluripotent stem cell transition into the primed state, compromising adequate lineage differentiation, thus suggesting that differential expression of p73 isoforms acts as a rheostat during early cell fate determinationSIThis work was supported by Grants PID2019-105169RB-I00 from Spanish Ministerio de Ciencia e Innovación cofinanced by FEDER funds (to M.C.M.) and LE021P17 from Junta de Castilla y Leon. L.L.-F. was a holder of a postdoctoral contract “Juan de de la Cierva-Incorporacion” from Ministerio de Ciencia e Innovación. N.M.-G. and H.A.-O. are supported by a predoctoral scholarship from the Asociación Española contra el Cáncer (AECC). M.M.-L. was a recipient of a Torres Quevedo contract from Ministerio de Ciencia e Innovación at Biomar Microbial Technologies. Á.D.-M., J.V.-F. and L.M.-A. are funded by Junta de Castilla y Leó

p73 deficiency results in impaired self renewal and premature neuronal differentiation of mouse neural progenitors independently of p53

[EN] The question of how neural progenitor cells maintain its self-renewal throughout life is a fundamental problem in cell biology with implications in cancer, aging and neurodegenerative diseases. In this work, we have analyzed the p73 function in embryonic neural progenitor cell biology using the neurosphere (NS)-assay and showed that p73-loss has a significant role in the maintenance of neurosphere-forming cells in the embryonic brain. A comparative study of NS from Trp73-/-, p53KO, p53KO;Trp73-/- and their wild-type counterparts demonstrated that p73 deficiency results in two independent, but related, phenotypes: a smaller NS size (related to the proliferation and survival of the neural-progenitors) and a decreased capacity to form NS (self-renewal). The former seems to be the result of p53 compensatory activity, whereas the latter is p53 independent. We also demonstrate that p73 deficiency increases the population of neuronal progenitors ready to differentiate into neurons at the expense of depleting the pool of undifferentiated neurosphere-forming cells. Analysis of the neurogenic niches demonstrated that p73-loss depletes the number of neural-progenitor cells, rendering deficient niches in the adult mice. Altogether, our study identifies TP73 as a positive regulator of self-renewal with a role in the maintenance of the neurogenic capacity. Thus, proposing p73 as an important player in the development of neurodegenerative diseases and a potential therapeutic targetSILGC is beneficiary of a predoctoral fellowship from Consejo de Educación de la Junta de Castilla y León and RFA from Spanish Ministerio de Ciencia e Innovación. This work was supported by Grants SAF2009-07897 from Spanish Ministerio de Ciencia e Innovacion (to MCM), Grant from Cajas de Ahorro de Castilla y León (to MCM), and Grants LE030A07 (to MMM) and LE015A10-2 (to MCM) from the Junta de Castilla y Leó

p73 regulates ependymal planar cell polarity by modulating actin and microtubule cytoskeleton

[EN]Planar cell polarity (PCP) and intercellular junctional complexes establish tissue structure and coordinated behaviors across epithelial sheets. In multiciliated ependymal cells, rotational and translational PCP coordinate cilia beating and direct cerebrospinal fluid circulation. Thus, PCP disruption results in ciliopathies and hydrocephalus. PCP establishment depends on the polarization of cytoskeleton and requires the asymmetric localization of core and global regulatory modules, including membrane proteins like Vangl1/2 or Frizzled. We analyzed the subcellular localization of select proteins that make up these modules in ependymal cells and the effect of Trp73 loss on their localization. We identify a novel function of the Trp73 tumor suppressor gene, the TAp73 isoform in particular, as an essential regulator of PCP through the modulation of actin and microtubule cytoskeleton dynamics, demonstrating that Trp73 is a key player in the organization of ependymal ciliated epithelia. Mechanistically, we show that p73 regulates translational PCP and actin dynamics through TAp73-dependent modulation of non-musclemyosin-II activity. In addition, TAp73 is required for the asymmetric localization of PCP-core and global signaling modules and regulates polarized microtubule dynamics, which in turn set up the rotational PCP. Therefore, TAp73 modulates, directly and/or indirectly, transcriptional programs regulating actin and microtubules dynamics and Golgi organization signaling pathways. These results shed light into the mechanism of ependymal cell planar polarization and reveal p73 as an epithelial architect during development regulating the cellular cytoskeletonSIThis work was supported by Grants SAF2015-71381-R from Spanish Ministerio de Economía y Competitividad co-financed by FEDER funds (to M.C.M.) and LE021P17 from Junta de Castilla y Leon, and from the Queen Elisabeth Medical Foundation to F.T. J.V.-F. and S.F.-A. are holders of predoctoral fellowships from the Junta de Castilla y León. L.M.-A. is supported by a predoctoral scholarship from the Asociación Española contra el Cáncer (AECC). F.T. is a Research Director of the FNRS. M.W. and M.L. are funded by the Deutsche Forschungsgemeinschaft (DFG) under grant number LI 2405/