Search

Melanie Gauthier,1,2 Julien Pierson,3 David Moulin,1 Manon Mouginot,1 Valerie Bourguignon,1 Wassim Rhalloussi,1 Jean-Baptiste Vincourt,1 Dominique Dumas,1 Danièle Bensoussan,1,2 Pascal Chastagner,1,4 Cédric Boura,3 Veronique Decot1,2 1CNRS UMR 7365 IMoPA, Université de Lorraine, Nancy, France; 2Cell Therapy and Tissue Bank Unit, Nancy University Hospital, Vandoeuvre-Les-Nancy, France; 3CNRS UMR7039 CRAN, Université de Lorraine, Nancy, France; 4Pediatric Oncology Department, Nancy University Hospital, Vandoeuvre-Les-Nancy, FranceCorrespondence: Veronique Decot, CNRS UMR 7365, IMoPA, Campus Brabois Santé, 9 av de la foret de Haye, Vandoeuvre-Les-Nancy, 54000, France, Tel +0033 – 649574720, Email veronique.decot@univ-lorraine.frPurpose: Medulloblastoma (MB) is the most prevalent paediatric brain tumour. Despite improvements in patient survival with current treatment strategies, the quality of life of these patients remains poor owing to the sequelae and relapse risk. An alternative, or, in addition to the current standard treatment, could be considered immunotherapy, such as Natural Killer cells (NK). NK cells are cytotoxic innate lymphoid cells that play a major role in cancer immunosurveillance. To date, the mechanism of cytotoxicity of NK cells, especially regarding the steps of adhesion, conjugation, cytotoxic granule polarisation in the cell contact area, perforin and granzyme release in two and three dimensions, and therapeutic efficacy in vivo have not been precisely described.Materials and Methods: Each step of NK cytotoxicity against the three MB cell lines was explored using confocal microscopy for conjugation, Elispot for degranulation, flow cytometry, and luminescence assays for target cell necrosis and lysis and mediators released by cytokine array, and then confirmed in a 3D spheroid model. Medulloblastoma-xenografted mice were treated with NK cells. Their persistence was evaluated by flow cytometry, and their efficacy in tumour growth and survival was determined. In addition, their effects on the tumour transcriptome were evaluated.Results: NK cells showed variable affinities for conjugation with MB target cells depending on their subgroup and cytokine activation. Chemokines secreted during NK and MB cell co-culture are mainly associated with angiogenesis and immune cell recruitment. NK cell cytotoxicity induces MB cell death in both 2D and 3D co-culture models. NK cells initiated an inflammatory response in a human MB murine model by modulating the MB cell transcriptome.Conclusion: Our study confirmed that NK cells possess both in vitro and in vivo cytotoxic activity against MB cells and are of interest for the development of immunotherapy.Keywords: cancer, medulloblastoma, immune cells, adoptive transfer

Mickaël Gries, 1 Noémie Thomas, 1 Joël Daouk, 1 Paul Rocchi, 2 Laurence Choulier, 3 Justine Jubréaux, 1 Julien Pierson, 1 Aurélie Reinhard, 1 Valérie Jouan-Hureaux, 1 Alicia Chateau, 1 Samir Acherar, 4 Céline Frochot, 5 François Lux, 2– 6 Olivier Tillement, 2 Muriel Barberi-Heyob 1 1Université de Lorraine, Centre National de la Recherche Scientifique (CNRS), Research Center for Automatic Control of Nancy (CRAN), Nancy, France; 2Université de Lyon, CNRS, Institut Lumière Matière, Lyon, France; 3Université de Strasbourg, CNRS, Biotechnologie et Signalisation Cellulaire, Illkirch, France; 4Université de Lorraine, CNRS, Laboratoire de Chimie-Physique Macromoléculaire, Nancy, France; 5Université de Lorraine, CNRS, Laboratoire Réactions et Génie des Procédés, Nancy, France; 6Institut Universitaire de France, Paris, FranceCorrespondence: Muriel Barberi-Heyob Email muriel.barberi@univ-lorraine.frBackground: Local recurrences of glioblastoma (GBM) after heavy standard treatments remain frequent and lead to a poor prognostic. Major challenges are the infiltrative part of the tumor tissue which is the ultimate cause of recurrence. The therapeutic arsenal faces the difficulty of eradicating this infiltrating part of the tumor tissue while increasing the targeting of tumor and endogenous stromal cells such as angiogenic endothelial cells. In this aim, neuropilin-1 (NRP-1), a transmembrane receptor mainly overexpressed by endothelial cells of the tumor vascular system and associated with malignancy, proliferation and migration of GBM, highlighted to be a relevant molecular target to promote the anti-vascular effect of photodynamic therapy (VTP).Methods: The multiscale selectivity was investigated for KDKPPR peptide moiety targeting NRP-1 and a porphyrin molecule as photosensitizer (PS), both grafted onto original AGuIX design nanoparticle. AGuIX nanoparticle, currently in Phase II clinical trials for the treatment of brain metastases with radiotherapy, allows to achieve a real-time magnetic resonance imaging (MRI) and an accumulation in the tumor area by EPR (enhanced permeability and retention) effect. Using surface-plasmon resonance (SPR), we evaluated the affinities of KDKPPR and scramble free peptides, and also peptides-conjugated AGuIX nanoparticles to recombinant rat and human NRP-1 proteins. For in vivo selectivity, we used a cranial window model and parametric maps obtained from T2*-weighted perfusion MRI analysis.Results: The photophysical characteristics of the PS and KDKPPR molecular affinity for recombinant human NRP-1 proteins were maintained after the functionalization of AGuIX nanoparticle with a dissociation constant of 4.7 μM determined by SPR assays. Cranial window model and parametric maps, both revealed a prolonged retention in the vascular system of human xenotransplanted GBM. Thanks to the fluorescence of porphyrin by non-invasive imaging and the concentration of gadolinium evaluated after extraction of organs, we checked the absence of nanoparticle in the brains of tumor-free animals and highlighted elimination by renal excretion and hepatic metabolism.Conclusion: Post-VTP follow-ups demonstrated promising tumor responses with a prolonged delay in tumor growth accompanied by a decrease in tumor metabolism.Keywords: vascular photodynamic therapy, AGuIX nanoparticle, NRP-1, peptide, brain tumors, glioblastoma, radiation therapies

The study of rhythms and oscillations in the brain is gaining attention. While it is unclear exactly what the role of oscillation, synchrony, and rhythm is, it appears increasingly likely that synchrony is related to normal and abnormal brain states and possibly cognition. In this article, we explore the relationship between basal ganglia (BG) synchrony and reinforcement learning. We simulate a biologically-realistic model of the striatum initially proposed by Ponzi and Wickens (2010) and enhance the model by adding plastic cortico-BG synapses that can be modified using reinforcement learning. The effect of reinforcement learning on striatal rhythmic activity is then explored, and disrupted using simulated deep brain stimulation (DBS). The stimulator injects current in the brain structure to which it is attached, which affects neuronal synchrony. The results show that training the model without DBS yields a high accuracy in the learning task and reduced the number of active neurons in the striatum, along with an increased firing periodicity and a decreased firing synchrony between neurons in the same assembly. In addition, a spectral decomposition shows a stronger signal for correct trials than incorrect trials in high frequency bands. If the DBS is ON during the training phase, but not the test phase, the amount of learning in the model is reduced, along with firing periodicity. Similar to when the DBS is OFF, spectral decomposition shows a stronger signal for correct trials than for incorrect trials in high frequency domains, but this phenoemenon happens in higher frequency bands than when the DBS is OFF. Synchrony between the neurons is not affected. Finally, the results show that turning the DBS ON at test increases both firing periodicity and striatal synchrony, and spectral decomposition of the signal show that neural activity synchronizes with the DBS fundamental frequency (and its harmonics). Turning the DBS ON during the test phase results in chance performance regardless of whether the DBS was ON or OFF during training. We conclude that reinforcement learning is related to firing periodicity, and a stronger signal for correct trials when compared to incorrect trials in high frequency bands.

Composition-driven amorphous-to-crystalline transition is widely observed in sputter-deposited thin films. We have recently shown that peculiar two-phase crystalline–amorphous nanostructures can be obtained for compositions in the transition zone between single-phased amorphous and crystalline films, offering a new possibility to control surface topography and related functional properties. Here, the growth kinetics of the two-phase nanostructures formed in the transition zone is explored and related to residual stress measurements. From the analysis of top-view scanning electron microscopy images, the evolution with the film thickness of relevant parameters describing the growth process was extracted, i.e., surface coverage, volume fraction, and perimeter per unit area of the crystalline regions growing in competition with the amorphous ones. We demonstrate, supported in the aforementioned parameters, that residual stress evolution in the transition zone is governed by the nucleation, growth, and interaction of the crystalline regions during the competitive growth process. Our results shed new light on the kinetics of the crystalline–amorphous competitive growth phenomenon and demonstrate the relevance of residual stress measurements for exploring the growth mechanisms of complex film microstructures. [ABSTRACT FROM AUTHOR]

Heteroepitaxial c-(Ti0.37,Al0.63)N thin films were grown on MgO(001) and MgO(111) substrates using reactive magnetron sputtering. High resolution high-angle annular dark-field scanning transmission electron micrographs show coherency between the film and the substrate. In the as-deposited state, x-ray diffraction reciprocal space maps show a strained epitaxial film. Corresponding geometric phase analysis (GPA) deformation maps show a high stress in the film. At elevated temperature (900 °C), the films decompose to form iso-structural coherent c-AlN- and c-TiN-rich domains, elongated along the elastically soft <100> directions. GPA analysis reveals that the c-TiN domains accommodate more dislocations than the c-AlN domains. This is because of the stronger directionality of the covalent bonds in c-AlN compared with c-TiN, making it more favorable for the dislocations to accumulate in c-TiN. The defect structure and strain generation in c-(Ti,Al)N during spinodal decomposition is affected by the chemical bonding state and elastic properties of the segregated domains. [ABSTRACT FROM AUTHOR]

Aspects on the phase stability and mechanical properties of nitrogen deficient (Ti0.54Al0.46)Ny alloys were investigated. Solid solution alloys of (Ti,Al)N were grown by cathodic arc deposition. The kinetic energy of the impinging ions was altered by varying the substrate bias voltage from –30V to –80 V. Films deposited with a high bias value of –80V showed larger lattice parameter, finer columnar structure, and higher compressive residual stress resulting in higher hardness than films biased at –30V when comparing their as-deposited states. At elevated temperatures, the presence of nitrogen vacancies and point defects (anti-sites and self-interstitials generated by the ion bombardment during coating deposition) in (Ti0.54Al0.46)N0.87 influence the driving force for phase separation. Highly biased nitrogen deficient films have point defects with higher stability during annealing, which cause a delay of the release of the stored lattice strain energy and then accelerates the decomposition tendencies to thermodynamically stable c-TiN and w-AlN. Low biased nitrogen deficient films have retarded phase transformation to w-AlN, which results in the prolongment of age hardening effect up to 1100 °C, i.e., the highest reported temperature for Ti-Al-N material system. Our study points out the role of vacancies and point defects in engineering thin films with enhanced thermal stability and mechanical properties for high temperature hard coating applications. [ABSTRACT FROM AUTHOR]

Conductive nitrides, such as TiN, are key engineering materials for electronics, photonics, and plasmonics; one of the essential issues for such applications is the ability of tuning the conduction electron density, the resistivity, and the electron scattering. While enhancing the conduction electron density and blueshifting the intraband absorption towards the UV were easily achieved previously, reducing the conduction electron density and redshifting the intraband absorption into the infrared are still an open issue. The latter is achieved in this work by alloying TiN by rare earth (RE=Sc, Y, La) or alkaline earth (AE=Mg, Ca) atoms in Ti substitutional positions. The produced TixRE1-xN and TixAE1-xN thin film samples were grown by a hybrid arc evaporation/sputtering process, and most of them are stable in the B1 cubic structure. Their optical properties were studied in an extensive spectral range by spectroscopic ellipsometry. The ellipsometric spectra were analyzed and quantified by the Drude-Lorentz model, which provided the conduction electron density, the electron mean free path, and the resistivity. The observed interband transitions are firmly assigned, and the optical and electrical properties of TixRE1-xN and TixAE1-xN are quantitatively correlated with their composition and crystal structure. [ABSTRACT FROM AUTHOR]