Deciphering the role and the mechanism of B- cell Non-Hodgkin Lymphoma-derived small Extracellular Vesicles in modulating the phenotype of myeloid cells.

Non-Hodgkin Lymphomas (NHL) represent one of the most common cancers worldwide. Among the most common forms of NHL are found Chronic Lymphocytic Leukemia (CLL), Diffuse Large B-cell Leukemia (DLBCL), and Follicular Lymphoma (FL). NHL is characterized by an expansion of myeloid cells with pro-tumoral properties, such as Tumor-associated macrophages (TAMs) or Myeloid-derived Suppressor Cells (MDSCs). However, little is known about the tumoral mechanisms leading to the expansion of those cell populations. It was recently suggested that small extracellular vesicles (sEVs) secreted by tumor cells may contribute to the polarization of myeloid cells. Indeed, the treatment of myeloid cells with CLL- derived sEVs leads to an upregulation of PD-L1 at the surface of myeloid cells and an increased secretion of pro-inflammatory cytokines. Interestingly, CLL-derived sEVs were enriched in yRNA4, a small non-coding RNA. Treatment of myeloid cells with yRNA4 induces a similar response of myeloid cells to treatment with CLL-derived sEVs. This effect depends on the Toll-Like Receptor (TLR) 7, a member of the TLR family, and may be relevant for all small RNAs contained in sEVs. In this dissertation, I first investigated the involvement of other TLR in response to treatment with CLL-derived sEVs. I searched for candidate sEV-proteins that could drive the polarization of myeloid cells into a pro-tumoral phenotype. In parallel, I investigated the role played by yRNA4 in the polarization of myeloid cells. As a first step, this dissertation presents a new approach for isolating and characterizing sEVs from human or murine lymphoid tissues. This approach combines differential centrifugation with size-exclusion chromatography, and turned out to be superior to previously used ultracentrifugation on a sucrose density cushion in terms of purity and yield of sEVs. A second step shows that the proteomic signature induced in myeloid cells following treatment with CLL-derived sEVs was broader than the signature induced in myeloid cells by yRNA4. The capacity of sEVs to induce a pro-inflammatory phenotype was tested using murine myeloid cells deficient for either TLR4, TLR7, or Myd88. Loss of TLR4 but not TLR7 nor Myd88 in myeloid cells leads to an impaired polarization of myeloid cells by tumor-derived sEVs. The activation of TLR2 and TLR4 following treatment with tumor-derived sEVs was also proven by using reporter cell assays. Next, I searched for potential TLR ligands present in NHL-derived sEVs. A proteomic comparison was performed with sEVs derived from the lymph nodes (LNs) of patients diagnosed with two subtypes of NHL, DLBCL and FL, as well as sEVs from patients with reactive lymph nodes as a non-tumoral control. Tumor LNs from DLBCL or FL patients were enriched in sEVs compared to reactive LNs. However, we observed a differential signature between the proteome of DLBCL-derived and FL-derived sEVs. Proteins unique to DLBCL- derived sEVs were primarily related to RNA processing, while proteins unique to FL-derived sEVs were more related to metabolism, among other pathways. Interestingly, sEVs from all 4 sources were found to be particularly enriched with Heat Shock Proteins (HSP), a family of proteins known to be endogenous ligands of TLRs. Finally, a knock-out of yRNA4 was induced using the CRISPR/Cas9 approach in the cell line HG-3, modeling CLL. The knock-out was validated using classical and real-time quantitative polymerase chain reactions and a Northern-blot assay. yRNA4 knock-out did not impair the capacity of the cells to secrete sEVs, nor their morphology, as investigated using transmission electron microscopy. However, sEVs derived from the yRNA4-deficient cell line showed a decreased capacity to induce the inflammatory phenotype in myeloid cells. The results raise the new hypothesis, that the reduced capacity of yRNA4-KO sEVs is due not only to the sole absence of yRNA4 but that the deletion of yRNA4 may impact the protein cargo loaded into the sEVs. Altogether, this dissertation allowed to decipher deeper the mechanisms by which tumor- derived sEVs influence the phenotype of myeloid cells. This mechanism was shown to be mediated by TLR2, TLR4 and TLR7; and the bioactive ligands include single-stranded RNAs such as yRNA4, as well as proteins, in particular the Heat-Shock Proteins. In the future, these findings may help finding new therapeutical targets to inhibit the modulation of the tumor microenvironment by tumor cells

Ecoulements diphasiques liquide-gaz en régime à bulles dans les lits fixes : étude expérimentale et modélisations mono- et bi-dimensionnelles

National audienceCet article présente une nouvelle modélisation 1D des écoulements diphasiques en lits fixes granulaire sbasé sur une approche mécaniste de type bi-fluide. La structure des lois de fermetures du modèle, déduite des mécanismes à micro-échelle, est validée par des expériences. Enfin, sur la base d’observations expérimentales, une proposition d’extension du modèle à des configurations 2D ou 3D est présentée

EOMES and IL-10 regulate antitumor activity of T regulatory type 1 CD4 + T cells in chronic lymphocytic leukemia

The transcription factor eomesodermin (EOMES) promotes interleukin (IL)-10 expression in CD4(+) T cells, which has been linked to immunosuppressive and cytotoxic activities. We detected cytotoxic, programmed cell death protein-1 (PD-1) and EOMES co-expressing CD4(+) T cells in lymph nodes (LNs) of patients with chronic lymphocytic leukemia (CLL) or diffuse large B-cell lymphoma. Transcriptome and flow cytometry analyses revealed that EOMES does not only drive IL-10 expression, but rather controls a unique transcriptional signature in CD4(+) T cells, that is enriched in genes typical for T regulatory type 1 (T(R)1) cells. The T(R)1 cell identity of these CD4(+) T cells was supported by their expression of interferon gamma and IL-10, as well as inhibitory receptors including PD-1. T(R)1 cells with cytotoxic capacity accumulate also in Eµ-TCL1 mice that develop CLL-like disease. Whereas wild-type CD4(+) T cells control TCL1 leukemia development after adoptive transfer in leukopenic Rag2(−/)(−) mice, EOMES-deficient CD4(+) T cells failed to do so. We further show that T(R)1 cell-mediated control of TCL1 leukemia requires IL-10 receptor (IL-10R) signaling, as Il10rb-deficient CD4(+) T cells showed impaired antileukemia activity. Altogether, our data demonstrate that EOMES is indispensable for the development of IL-10-expressing, cytotoxic T(R)1 cells, which accumulate in LNs of CLL patients and control TCL1 leukemia in mice in an IL-10R-dependent manner

Displacements

Displacements   es un proyecto  participativo de Marie Ange Bordas que aborda la experiencia  de los refugiados por medio de talleres artísticos y la realización de exposiciones dentro y fuera de sus comunidades

Deslocamentos: uma proposta de integração por meio da arte

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Benjamin Constant: l'esprit d'une oeuvre

International audienceDoué d’une parole précise et cinglante, Benjamin Constant a été un journaliste et un homme politique de premier plan, depuis les dernières années de la Révolution jusqu’à la fin de la Restauration. Ses écrits politiques constituent un jalon essentiel de la réflexion sur les fondements de la société démocratique et de la vie parlementaire, en France comme dans le monde. Dans le domaine de la création littéraire, le cursif Adolphe s’est imposé comme une œuvre majeure du roman à la première personne, et ses journaux sont un des chefs d’œuvre de l’écriture intime. Ouvrant une perspective nouvelle à la connaissance de Constant par la largeur du corpus envisagé, cet ouvrage analyse l’écriture, le style, la manière, tout ce qui fait la spécificité de l’esprit d’une œuvre qui ne ressemble à aucune autre : de la fiction littéraire aux essais politiques, de l’histoire de la religion à la réflexion sur le théâtre, c’est un art exemplaire de l’analyse et de l’argumentation, un style singulier qui nous est révélé

Caractérisation des écoulements à bulles en lits fixes (expériences et modélisation)

La maîtrise de l'hydrodynamique des réacteurs à lits fixes triphasiques constitue un enjeu industriel crucial pour leur dimensionnement ou pour accroître leur efficacité. Un modèle 1D à deux fluides des écoulements à bulles dans ces réacteurs est proposé qui incorpore de nouvelles formes des termes d'échange de quantité de mouvement entre les phases gaz, liquide et solide. Ces fermetures s'appuient sur des expériences conduites en lit fixe balayant une large gamme de paramètres. En outre, des expériences originales ont permis de quantifier, en dilué, la vitesse relative des bulles et leur distribution granulométrique : cette dernière s'avère être essentiellement contrôlée par la taille des interstices du lit. La structuration transverse des phases a également été abordée via des expériences permettant d'identifier et de quantifier les mécanismes la gouvernant. Un modèle 2D est proposé qui permet de simuler la propagation des déséquilibres radiaux des phases générés en entrée de réacteur.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Benjamin Constant: l'esprit d'une oeuvre

International audienceDoué d’une parole précise et cinglante, Benjamin Constant a été un journaliste et un homme politique de premier plan, depuis les dernières années de la Révolution jusqu’à la fin de la Restauration. Ses écrits politiques constituent un jalon essentiel de la réflexion sur les fondements de la société démocratique et de la vie parlementaire, en France comme dans le monde. Dans le domaine de la création littéraire, le cursif Adolphe s’est imposé comme une œuvre majeure du roman à la première personne, et ses journaux sont un des chefs d’œuvre de l’écriture intime. Ouvrant une perspective nouvelle à la connaissance de Constant par la largeur du corpus envisagé, cet ouvrage analyse l’écriture, le style, la manière, tout ce qui fait la spécificité de l’esprit d’une œuvre qui ne ressemble à aucune autre : de la fiction littéraire aux essais politiques, de l’histoire de la religion à la réflexion sur le théâtre, c’est un art exemplaire de l’analyse et de l’argumentation, un style singulier qui nous est révélé