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Grasp55 is a ubiquitous Golgi stacking protein involved in autophagy, protein trafficking, and glucose deprivation sensing. The function of Grasp55 in protein trafficking has been attributed to its PDZ-mediated interaction with the C-terminal PDZ-binding motifs of protein cargos. We have recently shown that such an interaction occurs between Grasp55 and the adhesion molecule Jam-C, which plays a central role in stemness maintenance of hematopoietic and spermatogenic cells. Accordingly, we have found that Grasp55-deficient mice suffer from spermatogenesis defects similar to Jam-C knockout mice. However, whether Grasp55 is involved in the maintenance of immunohematopoietic homeostasis through regulation of protein transport and Jam-C expression remains unknown. In this study, we show that Grasp55 deficiency does not affect hematopoietic stem cell differentiation, engraftment, or mobilization, which are known to depend on expression of Grasp55-dependent protein cargos. In contrast, using an Mycdependent leukemic model addicted to autophagy, we show that knockdown of Grasp55 in leukemic cells reduces spleen and bone marrow tumor burden upon i.v. leukemic engraftment. This is not due to reduced homing of Grasp55-deficient cells to these organs but to increased spontaneous apoptosis of Grasp55-deficient leukemic cells correlated with increased sensitivity of the cells to glucose deprivation. These results show that Grasp55 plays a role in Myc-transformed hematopoietic cells but not in normal hematopoietic cells in vivo. [ABSTRACT FROM AUTHOR]

Spermatogenesis is a dynamic process that is regulated by adhesive interactions between germ and Sertoli cells. Germ cells express the Junctional Adhesion Molecule-C (JAM-C, encoded by Jam3), which localizes to germ/Sertoli cell contacts. JAM-C is involved in germ cell polarity and acrosome formation. Using a proteomic approach, we demonstrated that JAM-C interacted with the Golgi reassembly stacking protein of 55 kDa (GRASP55, encoded by Gorasp2) in developing germ cells. Generation and study of Gorasp2-/- mice revealed that knock-out mice suffered from spermatogenesis defects. Acrosome formation and polarized localization of JAM-C in spermatids were altered in Gorasp2-/- mice. In addition, Golgi morphology of spermatocytes was disturbed in Gorasp2-/- mice. Crystal structures of GRASP55 in complex with JAM-C or JAM-B revealed that GRASP55 interacted via PDZ-mediated interactions with JAMs and induced a conformational change in GRASP55 with respect of its free conformation. An in silico pharmacophore approach identified a chemical compound called Graspin that inhibited PDZ-mediated interactions of GRASP55 with JAMs. Treatment of mice with Graspin hampered the polarized localization of JAM-C in spermatids, induced the premature release of spermatids and affected the Golgi morphology of meiotic spermatocytes. [ABSTRACT FROM AUTHOR]

To decipher the complex topology of lymphoid structures, we developed an automated process called Full Organ Reconstruction in 3D (For3D). A dedicated image-processing pipeline is applied to entire collections of immunolabeled serial sections, acquired with a slide-scanning microscope. This method is automated, flexible and readily applicable in two days to frozen or paraffin-embedded organs stained by fluorescence or brightfield immunohistochemistry. 3D-reconstructed organs can be visualized, rotated and analyzed to quantify substructures of interest. Usefulness of For3D is exemplified here through topological analysis of several mouse lymphoid organs exhibiting a complex organization: (i) the thymus, composed of two compartments, a medulla intricately imbricated into a surrounding cortex, (ii) lymph nodes, also highly compartmentalized into cortex, paracortex and medulla and (iii) the vascularization of an EG7 primary thymoma. This open-source algorithm, based on ImageJ and Matlab scripts, offers a user-friendly interface and is widely applicable to any organ or tissue, hence readily adaptable to a broad range of biomedical samples. [ABSTRACT FROM AUTHOR]

Capable of generating plasmonic and other effects, gold nanostructures can offer a variety of diagnostic and therapy functionalities for biomedical applications, but conventional chemically-synthesized Au nanomaterials cannot always match stringent requirements for toxicity levels and surface conditioning. Laser-synthesized Au nanoparticles (AuNP) present a viable alternative to chemical counterparts and can offer exceptional purity (no trace of contaminants) and unusual surface chemistry making possible direct conjugation with biocompatible polymers (dextran, polyethylene glycol). This work presents the first pharmacokinetics, biodistribution and safety study of laser-ablated dextran-coated AuNP (AuNPd) under intravenous administration in small animal model. Our data show that AuNPd are rapidly eliminated from the blood circulation and accumulated preferentially in liver and spleen, without inducing liver or kidney toxicity, as confirmed by the plasmatic ALAT and ASAT activities, and creatininemia values. Despite certain residual accumulation in tissues, we did not detect any sign of histological damage or inflammation in tissues, while IL-6 level confirmed the absence of any chronic inflammation. The safety of AuNPd was confirmed by healthy behavior of animals and the absence of acute and chronic toxicities in liver, spleen and kidneys. Our results demonstrate that laser-synthesized AuNP are safe for biological systems, which promises their successful biomedical applications. [ABSTRACT FROM AUTHOR]

Résumé De nombreux patients sont porteurs de plusieurs voies d’abord permettant l’administration conjointe de médicaments et d’autres traitements, incluant la nutrition entérale. Avec la multiplication des voies d’abord, le risque d’erreur de connexions augmente et peut conduire à des événements indésirables graves, voire fatals. L’une des principales raisons de ces événements indésirables iatrogènes est la présence ubiquitaire de connecteurs compatibles avec le Luer-Lock dans de multiples abords : entéral, urologique, respiratoire, épidural, intrathécal. Un projet de sécurisation de ces connectiques est en cours via une évolution normative. Les premières normes de l’International Organization for Standardization (ISO) concerneront la nutrition entérale, pour les connexions tubulure–sondes (ISO 80369-3, connectique ENFit), puis tubulure–contenant (ISO 18250-3, connectique EN+). Cette avancée normative induira la modification de toutes les connectiques de nutrition entérale actuellement sur le marché en connectiques standardisées et dédiées. Cette modification nécessitera une période de transition, avec des adaptateurs, pour passer des anciennes connectiques aux nouvelles. Comme pour toute phase de transition, une vigilance sera nécessaire quant aux risques d’incompatibilité entre les systèmes propriétaires et la nouvelle connectique standardisée. Dans ce contexte, nous illustrons les différents systèmes commercialisés à l’heure actuelle et présentons les évolutions réglementaires en cours qui aboutiront à la connectique EN+ et à la future connectique entérale standardisée ENFit, qui seront adoptées courant 2016 par tous les utilisateurs et les fournisseurs. La norme ENFit (ISO 80369-3) devrait être publiée courant 2015, et les nouvelles sondes et seringues de nutrition entérale disponibles dès 2016. La norme EN+ n’est pas encore publiée mais déjà mise en œuvre par 3 fournisseurs de nutrition entérale sur 4. Some patients may have multiple tubing lines connected to them for reasons such as delivery of medication and nutrition therapy. With these multiple lines, the risk for tubing misconnections becomes more prevalent and can lead to serious adverse and even fatal events. The main reason for these iatrogenic adverse events is the ubiquitous presence of Luer-lock in direct points of access: enteral, urological, respiratory, epidural, intrathecal. The International Organization for Standardization (ISO) characterizes a connector securing project to avoid tubing misconnections. Firstly, this approach concerns enteral nutrition lines connections (ISO 80369-3, ENFit) and lines-containing (ISO 18250-3, EN+). This normative project induces the modification of enteral connectors to standardized and dedicated connectors. Connectors evolution will require a transition period, with adapters to switch to new enteral devices. As with any transition, vigilance will be needed on the risks of incompatibility between currently devices and the new standardized connectors. We illustrate the different systems used today and present regulatory changes underway that will lead to the EN+ connectivity and future connectivity standard enteral ENFit. The ISO 80369-3 standard is expected in 2015 and the new enteral devices will be available from 2016. The EN+ is not yet published but is already available into 3 enteral devices suppliers of 4. [ABSTRACT FROM AUTHOR]

Triple‐negative breast cancer (TNBC) is a highly aggressive breast cancer subtype characterized by a remarkable molecular heterogeneity. Currently, there are no effective druggable targets and advanced preclinical models of the human disease. Here, a unique mouse model (MMTV‐R26Met mice) of mammary tumors driven by a subtle increase in the expression of the wild‐type MET receptor is generated. MMTV‐R26Met mice develop spontaneous, exclusive TNBC tumors, recapitulating primary resistance to treatment of patients. Proteomic profiling of MMTV‐R26Met tumors and machine learning approach show that the model faithfully recapitulates intertumoral heterogeneity of human TNBC. Further signaling network analysis highlights potential druggable targets, of which cotargeting of WEE1 and BCL‐XL synergistically kills TNBC cells and efficiently induces tumor regression. Mechanistically, BCL‐XL inhibition exacerbates the dependency of TNBC cells on WEE1 function, leading to Histone H3 and phosphoS33RPA32 upregulation, RRM2 downregulation, cell cycle perturbation, mitotic catastrophe, and apoptosis. This study introduces a unique, powerful mouse model for studying TNBC formation and evolution, its heterogeneity, and for identifying efficient therapeutic targets. [ABSTRACT FROM AUTHOR]