Search

2024 Acuerdos transformativos CRUE-CSIC, Both EphB2- and EphB3-deficient mice exhibit profound histological alterations in the thymic epithelial network but few changes in T-cell differentiation, suggesting that this organization would be sufficient to produce functional T lymphocytes. Also, other antigen-presenting cells involved in immunological education could substitute the thymic epithelium. Accordingly, we found an increased frequency of plasmacytoid dendritic cells but not of conventional dendritic cells, medullary fibroblasts or intrathymic B lymphocytes. In addition, there are no lymphoid infiltrates in the organs of mutant mice nor do they contain circulating autoantibodies. Furthermore, attempts to induce arthritic lesions after chicken type II collagen administration fail totally in EphB2-deficient mice whereas all WT and half of the immunized EphB3−/− mice develop a typical collagen-induced arthritis. Our results point out that Th17 cells, IL4-producing Th2 cells and regulatory T cells are key for the induction of disease, but mutant mice appear to have deficits in T cell activation or cell migration properties. EphB2−/− T cells show reduced in vitro proliferative responses to anti-CD3/anti-CD28 antibodies, produce low levels of anti-type II collagen antibodies, and exhibit low proportions of T follicular helper cells. On the contrary, EphB3−/− lymph node cells respond accurately to the different immune stimuli although in lower levels than WT cells but show a significantly reduced migration in in vitro transwell assays, suggesting that no sufficient type II collagen-dependent activated lymphoid cells reached the joints, resulting in reduced arthritic lesions., Unión Europea. NextGenerationEU. Plan de Recuperación Transformación y Resiliencia, Ministerio de Ciencia, Innovación y Universidades, Instituto de Salud Carlos III, Depto. de Biología Celular, Fac. de Ciencias Biológicas, TRUE, pub

Depto. de Biología Celular, Fac. de Ciencias Biológicas, TRUE, pub

2023 Acuerdos transformativos CRUE, In the present study, we review the structure and function of fish spleen with special emphasis on its condition in Elasmobranchs, Teleosts and Lungfish. Apart from the amount of splenic lymphoid tissue, the histological organization of the organ ensures the existence of areas involved in antigen trapping, the ellipsoids, and exhibit numerous melano-macrophages which appear isolated or forming the so-called melano-macrophage centres. An extensive discussion on the functional significance of these centres conclude that they are mere accumulations of macrophages consequence of tissue homeostasis rather than primitive germinal centres, as proposed by some authors., Depto. de Biología Celular, Fac. de Ciencias Biológicas, TRUE, pub, APC financiada por la UCM

During the acute phase of Chagas disease, Trypanosoma cruzi circulation through the bloodstream leads to high tissue parasitism in the host. In primary lymphoid organs, progenitor cell reduction paralleled transient immunosuppression. Herein we showed that acute oral infection in mice promotes diffuse parasitism in bone marrow cells at 14 and 21 days post-infection (dpi), with perivascular regions, intravascular regions, and regions near the bone being target sites of parasite replication. Phenotypic analysis of hematopoietic differentiation in the bone marrow of infected mice showed that the cell number in the tissue is decreased (lineage-negative and lineage-positive cells). Interestingly, analysis of hematopoietic branching points showed that hematopoietic stem and progenitor cells (HSPCs) were significantly increased at 14 dpi. In addition, the pool of progenitors with stem plasticity (HSC-MPP3), as well as multipotent progenitors (MPPs) such as MPP4, also showed this pattern of increase. In contrast, subsequent progenitors that arise from MPPs, such as common lymphoid progenitors (CLPs), lymphoid-primed MPPs (LMPPs), and myeloid progenitors, were not enhanced; conversely, all presented numeric decline. Annexin V staining revealed that cell death increase in the initial hematopoietic branching point probably is not linked to CLPs and that myeloid progenitors decreased at 14 and 21 dpi. In parallel, our investigation provided clues that myeloid progenitor decrease could be associated with an atypical expression of Sca-1 in this population leading to a remarkable increase on LSK-like cells at 14 dpi within the HSPC compartment. Finally, these results led us to investigate HSPC presence in the spleen as a phenomenon triggered during emergency hematopoiesis due to mobilization or expansion of these cells in extramedullary sites. Splenocyte analysis showed a progressive increase in HSPCs between 14 and 21 dpi. Altogether, our study shows that the bone marrow is a tar, Durante la fase aguda de la enfermedad de Chagas, la circulación de Trypanosoma cruzi a través del torrente sanguíneo genera una elevada parasitación tisular en el huésped. En los órganos linfoides primarios, la reducción de células progenitoras es paralela a la inmunosupresión transitoria. Aquí demostramos que la infección oral aguda en ratones promueve un parasitismo difuso en las células de la médula ósea a los 14 y 21 días post-infección (dpi), siendo las regiones perivasculares, las intravasculares y las cercanas al hueso los sitios objetivo de replicación del parásito. En conjunto, nuestro estudio muestra que la médula ósea es un tejido diana en los ratones infectados por vía oral por T. cruzi, lo que conduce a una alteración hematopoyética del número de células HSPCs que posiblemente afecta al número de progenitores mieloides. La reducción de LMPP y CLP se relaciona con un desarrollo defectuoso de los timocitos. Por último, es tentador especular que la hematopoyesis extramedular observada en el bazo es un mecanismo implicado en el mantenimiento hematológico detectado durante la fase aguda de la infección oral por T. cruzi., Coordination for the Improvement of Higher Education Personnel (CAPES), Brazilian National Research Council, Carlos Chagas Foundation for funding research in the State of Rio de Janeiro, Oswaldo Cruz Institute/Fiocruz, Mercosur Fund for Structural Convergence, Depto. de Biología Celular, Fac. de Ciencias Biológicas, TRUE, pub

Mesenchymal stromal/stem cells (MSCs) have emerged as important therapeutic agents, owing to their easy isolation and culture, and their remarkable immunomodulatory and anti-inflammatory properties. However, MSCs constitute a heterogeneous cell population which does not express specific cell markers and has important problems for in vivo homing, and factors regulating their survival, proliferation, and differentiation are largely unknown. Accordingly, in the present article, we review the current evidence on the relationships between Eph kinase receptors, their ephrin ligands, and MSCs. These molecules are involved in the adult homeostasis of numerous tissues, and we and other authors have demonstrated their expression in human and murine MSCs derived from both bone marrow and adipose tissue, as well as their involvement in the MSC biology. We extend these studies providing new results on the effects of Eph/ephrins in the differentiation and immunomodulatory properties of MSCs, Las células madre mesenquimales (MSC) se han convertido en importantes agentes terapéuticos, debido a su fácil aislamiento y cultivo, y a sus notables propiedades inmunomoduladoras y antiinflamatorias, aunque se desconocen múltiples aspectos de su biología. En este artículo revisamos los trabajos existentes sobre las MSC y los receptores Eph, y sus ligandos (ephrinas), ya que estas tirosina-kinasas participan en la homeostasis adulta de numerosos tejidos. Además, incorporamos nuevos resultados sobre los efectos de dicha señalización en la diferenciación y las propiedades inmunomoduladoras de las MSC., Ministerio de Ciencia, Innovación y Universidades (MICINN), Comunidad de Madrid, Instituto de Salud Carlos III (ISCIII) / FEDER, Depto. de Biología Celular, Fac. de Ciencias Biológicas, TRUE, pub

The mechanisms that determine the commitment of thymic epithelial precursors to the two major thymic epithelial cell lineages, cTECs and mTECs, remain unknown. Here we show that FoxN1 nu mutation, which abolishes thymic epithelium differentiation, results in the formation of a tubular branched structure according to a typical branching morphogenesis and tubulogenesis developmental pattern. In the presence of FoxN1, in alymphoid NSG and fetal Ikaros−/− thymi, there is no lumen formation and only partial apical differentiation. This initiates cortex–medulla differentiation inducing expression of medullary genes in the apically differentiating cells and of cortical genes in the non-apically differentiating cells, which will definitely differentiate in wt and postnatal Ikaros−/− mice. Therefore, the thymus development is based on a branching morphogenesis and tubulogenesis developmental pattern: FoxN1 expression in the thymic primordium inhibits tubulogenesis and induces the expression of genes involved in TEC differentiation, which culminates with the expression of functional cell markers, i.e., MHCII, CD80, Aire in both postnatal Ikaros−/− and WT thymi after arrival of lymphoid progenitor cells., Dos factores regulan el desarrollo del epitelio tímico, el factor de transcripción Foxn1 y las interacciones célula-célula entre timocitos y epitelio tímico, imprescindible a su vez para la maduración funcional de los timocitos. El trabajo re-evalúa el papel de ambos factores analizando comparativamente el desarrollo epitelial en timos sin Foxn1 ni timocitos (ratones nude), con Foxn1 pero sin timocitos (ratones NSG), con Foxn1 pero sin timocitos hasta después del nacimiento (ratones Ikaros-/-) y ratones WT con ambos factores durante todo el desarrollo. Los resultados confirman que el timo, como otras glándulas derivadas del endodermo, se desarrollan de acuerdo a un patrón de branching morphogenesis en el que la expresión de Foxn1 bloquea la formación del lumen de la glándula al tiempo que induce la diferenciación de genes epiteliales que culmina cuando la llegada de progenitores linfoides al primordio tímico induce la diferenciación de marcadores funcionales (MHC clase II, CD80, Aire)" Juan J. Muñoz, Esther Tobajas, Sonia Juara, Sara Montero, Agustín G. Zapata, Ministerio de Economía y Competitividad (MINECO), Depto. de Biología Celular, Fac. de Ciencias Biológicas, TRUE, pub

Numerous epithelia undergo tubulogenesis and branching morphogenesis during their development (i.e., lung, salivary gland, pancreas) in order to establish sufficient available surface for their proper functioning. The thymus is a primary lymphoid organ constituted by pharyngeal-derived epithelium necessary to produce immunocompetent lymphocytes whose mechanisms of development are not fully known. In the current chapter, we review histological, cellular, and molecular mechanisms governing early thymic epithelium development emphasizing its resemblance with the process of branching morphogenesis and tubulogenesis occurring in other epithelial organs in which epithelial-mesenchyme interactions determine the tissue patterning through specific combinations of common molecular signaling pathways., El timo es un órgano derivado del endodermo de las bolsas faríngeas donde progenitores linfoides maduran fenotípica y funcionalmente para generar el repertorio inmunológico de los linfocitos T. A pesar de la abundante literatura sobre este órgano, su embriogénesis temprana y las moléculas que la gobiernan siguen siendo objeto de controversia. En la presente revisión repasamos las evidencias que demuestran que el desarrollo tímico obedece, como el de otros órganos derivados del endodermo faríngeo (glándulas salivales y pulmón), a un proceso de tubulogénesis y branching morphogenesis que se ve modificado por la expresión del factor de transcripción FoxN1 imprescindible para la maduración del epitelio tímico, y por la llegada de los progenitores linfoides que organizan un red 3D epitelial necesaria para la maduración de los timocitos

The thymus is a primary lymphoid organ constituted by a 3D epithelial network that provides a specialized microenvironment in which seeding lymphoid progenitors undergo phenotypical and functional maturation. During the earlier steps of thymic organogenesis, the specification of the pharyngeal endoderm to thymus fate takes place independently of the expression of the transcription factor Foxn1 that, however, governs the later organogenesis of thymus together with the colonizing lymphoid cells. In the present chapter, we will review evidence describing early development of thymus and its resemblance with the development of endoderm-derived epithelial organs based on tubulogenesis and branching morphogenesis as well as the molecules known to be involved in these processes., Este capítulo de libro revisa los procesos de especificación del epitelio tímico inducidos por Foxn1 en el endodermo común de la tercera bolsa faríngea, el fenómeno de la tubulogénesis y el branching de dicho primordio y las moléculas implicadas en tales procesos así como el papel de los progenitores linfoides que colonizan el primordio tímico durante el desarrollo

This work was supported by the Spanish Ministry of Economy and Competitiveness under grants BFU2013-41112-R and Cell Therapy Network (RD12/0019/0007 and RD16/0011/0002)., EphB and their ligands ephrin-B are an important family of protein tyrosine kinase receptors involved in thymocyte-thymic epithelial cell interactions known to be key for the maturation of both thymic cell components. In the present study, we have analyzed the maturation of cortical thymic epithelium in EphB-deficient thymuses evaluating the relative relevance of EphB2 and EphB3 in the process. Results support a relationship between the epithelial hypocellularity of mutant thymuses and altered development of thymocytes, lower proportions of cycling thymic epithelial cells and increased epithelial cell apoptosis. Together, these factors induce delayed development of mutant cortical TECs, defined by the expression of different cell markers, i.e. Ly51, CD205, MHCII, CD40 and b5t. Furthermore, although both EphB2 and EphB3 are necessary for cortical thymic epithelial maturation, the relevance of EphB3 is greater since EphB3¡/¡ thymic cortex exhibits a more severe phenotype than that of EphB2-deficient thymuses., Ministerio de Economía y Competitividad, Red de Terapía Celular, Depto. de Biología Celular, Fac. de Ciencias Biológicas, TRUE, pub

Background aims The immunomodulatory properties of mesenchymal stromal cells (MSCs), together with their tissue regenerative potential, make them interesting candidates for clinical application. Methods In the current study, we analyzed the in vitro immunomodulatory effects of MSCs derived from bone marrow (BM-MSCs) and from adipose tissue (AT-MSCs) obtained from the same donor on both innate and acquired immunity cells. BM-MSCs and AT-MSCs were expanded to fourth or fifth passage and co-cultured with T cells, monocytes or natural killer (NK) cells isolated from human peripheral blood and stimulated in vitro. The possible differing impact of MSCs obtained from distinct sources on phenotype, cell proliferation and differentiation, cytokine production and function of these immune cells was comparatively analyzed. Results BM-MSCs and AT-MSCs induced a similar decrease in NK-cell proliferation, cytokine secretion and expression of both activating receptors and cytotoxic molecules. However, only BM-MSCs significantly reduced NK-cell cytotoxic activity, although both MSC populations showed the same susceptibility to NK-cell-mediated lysis. AT-MSCs were more potent in inhibiting dendritic-cell (DC) differentiation than BM-MSC, but both MSC populations similarly reduced the ability of DCs to induce CD4+ T-cell proliferation and cytokine production. BM-MSCs and AT-MSCs induced a similar decrease in T-cell proliferation and production of inflammatory cytokines after activation. Conclusions AT-MSCs and BM-MSCs from the same donor had similar immunomodulatory capacity on both innate and acquired immunity cells. Thus, other variables, such as accessibility of samples or the frequency of MSCs in the tissue should be considered to select the source of MSC for cell therapy., Ministerio de Economía y Competitividad (MINECO), Comunidad de Madrid, Instituto de Salud Carlos III, Fundación Científica Asociación Española Contra el Cáncer, Depto. de Biología Celular, Fac. de Ciencias Biológicas, TRUE, pub

Mesenchymal stem cells (MSCs) are key components of the bone marrow microenvironment which contribute to the maintenance of the hematopoietic stem cell niche and exert immunoregulatory functions in innate and adaptive immunity. We analyze the immunobiology of MSCs derived from acute lymphoblastic leukemia (ALL) patients and their impact on NK cell function. In contrast to the inhibitory effects on the immune response exerted by MSCs from healthy donors (Healthy-MSCs), we demonstrate that MSCs derived from low/intermediate risk ALL patients at diagnosis (ALL-MSCs) promote an efficient NK cell response including cytokine production, phenotypic activation and most importantly, cytotoxicity. Longitudinal studies indicate that these immunostimulatory effects of ALL-MSCs are progressively attenuated. Healthy-MSCs adopt ALL-MSC-like immunomodulatory features when exposed to leukemia cells, acquiring the ability to stimulate NK cell antitumor function. The mechanisms underlying to these functional changes of ALL-MSCs include reduced production of soluble inhibitory factors, differential expression of costimulatory and coinhibitory molecules, increased expression of specific TLRs and Notch pathway activation. Collectively our findings indicate that, in response to leukemia cells, ALL-MSCs could mediate a host beneficial immunomodulatory effect by stimulating the antitumor innate immune response., Ministerio de Economía y Competitividad (MINECO), Comunidad de Madrid, Asociación Española contra el Cáncer 2010, Instituto de Salud Carlos III (España), Depto. de Biología Celular, Fac. de Ciencias Biológicas, TRUE, pub

The signals that determine the survival/death of the thymic epithelial cells (TECs) component during embryonic development of the thymus are largely unknown. In this study, we combine different in vivo and in vitro experimental approaches to define the role played by the tyrosine kinase receptors EphB2 and EphB3 and their ligands, ephrinsB, in the survival of embryonic and newborn (NB) TECs. Our results conclude that EphB2 and EphB3 are involved in the control of TEC survival and that the absence of these molecules causes increased apoptotic TEC proportions that result in decreased numbers of thymic cells and a smaller-sized gland. Furthermore, in vitro studies using either EphB2-Fc or ephrinB1-Fc fusion proteins demonstrate that the blockade of Eph/ephrinB signalling increases TEC apoptosis, whereas its activation rescues TECs from cell death. In these assays, both heterotypic thymocyte–TEC and homotypic TEC–TEC interactions are important for Eph/ephrinB-mediated TEC survival., Ministerio de Educación y Ciencia, Ministerio de Salud y Consumo, Comunidad de Madrid/Universidad Complutense de Madrid, Depto. de Biología Celular, Fac. de Ciencias Biológicas, TRUE, pub