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Colombo E.,San Raffaele Scientific Institute | Colombo E.,Foundation IRCCS Neurological Institute Carlo Besta | Tentorio P.,San Raffaele Scientific Institute | Tentorio P.,Foundation IRCCS Neurological Institute Carlo Besta | And 7 more authors.
Clinical and Experimental Immunology | Year: 2014

Summary: B cell receptor (BCR) signalling determines B cell differentiation and may potentially alter T cell-mediated immune responses. In this study we used two transgenic strains of BCR-deficient mice expressing Epstein-Barr virus latent membrane protein (LMP)2A in B cells, where either follicular and marginal zone differentiation (DHLMP2A mice) or B-1 cell development (VHLMP2A mice) were supported, and evaluated the effects of skewed B lymphocyte differentiation on lymphoid organogenesis and T cell responses in vivo. Compared to wild-type animals, both transgenic strains displayed alterations in the composition of lymphoid organs and in the dynamics of distinct immune cell subsets following immunization with the self-antigen PLP185-206. However, ex-vivoT cell proliferation to PLP185-206 peptide measured in immunized DHLMP2A and VHLMP2A mice was similar to that detected in immunized control mice. Further, clinical expression of experimental autoimmune encephalitis in both LMP2A strains was identical to that of wild-type mice. In conclusion, mice with skewed B cell differentiation driven by LMP2A expression in BCR-negative B cells do not show changes in the development of a T cell mediated disease model of autoimmunity, suggesting that compensatory mechanisms support the generation of T cell responses. © 2013 British Society for Immunology. Source


Casola S.,The FIRC Institute of Molecular Oncology Foundation
Methods in molecular biology (Clifton, N.J.) | Year: 2010

In 1991, Soriano and coworkers isolated the ROSA26 locus in a gene-trap mutagenesis screening performed in mouse embryonic stem (ES) cells. The ubiquitous expression of ROSA26 in embryonic and adult tissues, together with the high frequency of gene-targeting events observed at this locus in murine ES cells has led to the establishment in the past 10 years of over 130 knock-in lines expressing successfully from the ROSA26 locus a variety of transgenes including reporters, site-specific recombinases and, recently, noncoding RNAs. Different strategies can be employed to drive transgene expression from the ROSA26 locus. This chapter provides an overview of the current methodologies used to generate ROSA26 knock-in lines and describes different approaches that exploit the ROSA26 gene to control expression of transgenes, including miRNAs, in a temporal, cell-type, and stage-specific fashion. Source


Corada M.,The FIRC Institute of Molecular Oncology Foundation | Nyqvist D.,The FIRC Institute of Molecular Oncology Foundation | Orsenigo F.,The FIRC Institute of Molecular Oncology Foundation | Caprini A.,The FIRC Institute of Molecular Oncology Foundation | And 7 more authors.
Developmental Cell | Year: 2010

The Wnt/β-catenin pathway is evolutionary conserved signaling system that regulates cell differentiation and organogenesis. We show that endothelial specific stabilization of Wnt/β-catenin signaling alters early vascular development in the embryo. The phenotype resembles that induced by upregulation of Notch signaling, including lack of vascular remodeling, altered elongation of the intersomitic vessels, defects in branching, and loss of venous identity. Both in vivo and in vitro data showthat β-catenin upregulates Dll4 transcription and strongly increases Notch signaling in the endothelium, leading to functional and morphological alterations. The functional consequences of β-catenin signaling depend on the stage of vascular development and are lost when a gain-of-function mutation is induced at a late stage of development or postnatally. Our findings establish a link between Wnt and Notch signaling in vascular development. We propose that early and sustained β-catenin signaling prevents correct endothelial cell differentiation, altering vascular remodeling and arteriovenous specification. © 2010 Elsevier Inc. Source


Feng Y.,University of Bristol | Santoriello C.,The FIRC Institute of Molecular Oncology Foundation | Mione M.,The FIRC Institute of Molecular Oncology Foundation | Hurlstone A.,University of Manchester | Martin P.,University of Bristol
PLoS Biology | Year: 2010

It has not previously been possible to live image the earliest interactions between the host environment and oncogenetransformed cells as they initiate formation of cancers within an organism. Here we take advantage of the translucency of zebrafish larvae to observe the host innate immune cell response as oncogene-transformed melanoblasts and goblet cells multiply within the larval skin. Our studies indicate activation of leukocytes at very early stages in larvae carrying a transformed cell burden. Locally, we see recruitment of neutrophils and macrophages by 48 h post-fertilization, when transformed cells are still only singletons or doublets, and soon after this we see intimate associations between immune and transformed cells and frequent examples of cytoplasmic tethers linking the two cell types, as well as engulfment of transformed cells by both neutrophils and macrophages. We show that a major component of the signal drawing inflammatory cells to oncogenic HRASG12V-transformed cells is H2O2, which is also a key damage cue responsible for recruiting neutrophils to a wound. Our short-term blocking experiments show that preventing recruitment of immune cells at these early stages results in reduced growth of transformed cell clones and suggests that immune cells may provide a source of trophic support to the transformed cells just as they do at a site of tissue repair. These parallels between the inflammatory responses to transformed cells and to wounds reinforce the suggestion by others that cancers resemble nonhealing wounds. © 2010 Feng et al. Source


Kumar R.,IFOM p53Lab Joint Research Laboratory | Kumar R.,Nanyang Technological University | Cheok C.F.,IFOM p53Lab Joint Research Laboratory | Cheok C.F.,The FIRC Institute of Molecular Oncology Foundation | And 2 more authors.
DNA Repair | Year: 2014

DNA double strand breaks (DSBs) are highly toxic to the cells and accumulation of DSBs results in several detrimental effects in various cellular processes which can lead to neurological, immunological and developmental disorders. Failure of the repair of DSBs spurs mutagenesis and is a driver of tumorigenesis, thus underscoring the importance of the accurate repair of DSBs. Two major canonical DSB repair pathways are the non-homologous end joining (NHEJ) and homologous recombination (HR) pathways. 53BP1 and BRCA1 are the key mediator proteins which coordinate with other components of the DNA repair machinery in the NHEJ and HR pathways respectively, and their exclusive recruitment to DNA breaks/ends potentially decides the choice of repair by either NHEJ or HR. Recently, Rap1 interacting factor 1 has been identified as an important component of the DNA repair pathway which acts downstream of the ATM/53BP1 to inhibit the 5'-3' end resection of broken DNA ends, in-turn facilitating NHEJ repair and inhibiting homology directed repair. Rif1 is conserved from yeast to humans but its function has evolved from telomere length regulation in yeast to the maintenance of genome integrity in mammalian cells. Recently its role in the maintenance of genomic integrity has been expanded to include the regulation of chromatin structure, replication timing and intra-S phase checkpoint. We present a summary of these important findings highlighting the various aspects of Rif1 functions and discuss the key implications for genomic integrity. © 2013 The Authors. Source

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