Biology subjects

Menard, A.

Publications and source records attributed to Menard, A..

3 recordsLinked to original sources

bioRxiv2022

Vγ9Vδ2 T cells are potent inhibitors of SARS-CoV-2 replication and exert effector phenotypes in COVID-19 patients

V{gamma}9V{delta}2 T cells play a key role in the innate immune response to viral infections, including SARS-CoV-1 and 2, and are activated through butyrophilin (BTN)-3A. Here, the objectives were to: 1) characterize the effects of SARS-CoV-2 infection on the number, phenotype, and activation of V{gamma}9V{delta}2 T cells in infected patients, and 2) assess the effects of in vitro SARS-CoV-2 infection on the expression of BTN3A and its impact on the activation and response of V{gamma}9V{delta}2 T cells to an anti-BTN3A antibody. Blood V{gamma}9V{delta}2 T cells decreased in clinically mild SARS-CoV-2 infections compared to healthy volunteers (HV). This decrease was maintained up to 28 days and in the recovery period. Terminally differentiated V{gamma}9V{delta}2 T cells tend to be enriched on the day of diagnosis, 28 days after and during the recovery period compared to HV. Furthermore, these cells showed cytotoxic and inflammatory activities as shown by TNF, IFN{gamma} and CD107a/b increase following anti-BTN3A activation. Moreover, BTN3A upregulation and V{gamma}9V{delta}2 T cell infiltration were observed in a lung biopsy from a fatal SARS-CoV-2 infection, as compared to HV. In vitro, SARS-CoV-2 infection significantly increased BTN3A expression in macrophages and lung cell lines. The activation via BTN3A enhanced the anti-SARS-CoV-2 V{gamma}9V{delta}2 T cells cytotoxicity and IFN-{gamma} and TNF in SARS-CoV-2 infected patient. Increasing concentrations of anti-BTN3A were accompanied by an inhibition of viral replication. Altogether, these data suggest that V{gamma}9V{delta}2 T cells are important in the immune response against SARS-CoV-2 infection and that activation by an anti-BTN3A antibody may enhance their response. KEY POINTSO_LISARS-CoV-2 mediates upregulation of the key receptor of V{gamma}9V{delta}2 T cells BTN3A on lung tissues and cell lines as well as monocytes C_LIO_LIDuring SARS-CoV-2 infection, V{gamma}9V{delta}2 are differentiated and efficiently degranulate and secrete cytokines upon activation with BTN3A mAb C_LI

immunology↗

bioRxiv2022

The cytolethal distending toxin modulates cell differentiation and elicits epithelial to mesenchymal transition

We are frequently exposed to bacterial genotoxins, such as cytolethal distending toxin (CDT), a prevalent heterotrimeric toxin whose active moiety is its CdtB subunit. CdtB triggers potent DNA damage, predisposing factors in the development of cancers, in host cells. CDT from Helicobacter hepaticus, a mouse pathogen, was shown to be directly involved in the development of murine hepatocarcinoma. Preliminary studies have shown that CDT induces certain phenotypes reminiscent of epithelial to mesenchymal transition (EMT), a process by which cells lose their epithelial characteristics in favor of mesenchymal ones, conducive to cell motility. In the present study, we investigated the different steps of EMT using liver tissues of mice infected with H. hepaticus, as well as human epithelial cell lines and xenograft mouse models following H. hepaticus CdtB expression. Most of the different steps of the EMT process were reproduced throughout the studied models. Indeed, microarray data showed a CdtB- dependent regulation of EMT-related transcripts. The key transcriptional regulators of EMT (SNAIL1 and ZEB1) and EMT markers (Vimentin, Fibronectin and 5{beta}1 integrin) were upregulated both at RNA and protein levels in response to CdtB. It also induced cell-cell junctions disassembly, causing individualization of cells and acquisition of a spindle-like morphology. CdtB activated the expression and activity of matrix metalloproteases and increased cell motility. This study demonstrated that CDT/CdtB elicits EMT process activation, supporting the idea that infection with genotoxin-producing bacteria can promote malignant transformation. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=96 SRC="FIGDIR/small/487255v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@f94756org.highwire.dtl.DTLVardef@1ba7d59org.highwire.dtl.DTLVardef@7b80ccorg.highwire.dtl.DTLVardef@44d56d_HPS_FORMAT_FIGEXP M_FIG C_FIG Author SummaryWe are frequently exposed to infection with genotoxin--producing bacterial from the gut microbiota, such as cytolethal distending toxin (CDT). CDT, via its active CdtB subunit, causes severe DNA damage in host cells, well-known risk factor of cancer development and progression. Chronic infection with CDT-producing bacteria is thus involved in cancer development. CDT is widespread among many bacteria and its impact in human cancer seems likely underestimated. Despite its major significance, CDT remains little studied. Here, we showed that cells exposed to CdtB are no longer cohesive, become individualized and acquire a spindle-shaped morphology known to be conducive to migration. These cells also express increased level of mesenchymal markers, as well as increased level of SNAIL1 and ZEB1, two key transcription factors orchestrating a crucial mechanism for cancer initiation and progression: epithelial to mesenchymal transition. These effects induced by CdtB were associated with increased matrix metalloproteinases degrading activity and emergence of cellular motility. Collectively, these data showed that CdB activates epithelial to mesenchymal transition, supporting the role of CDT in tumorigenesis.

microbiology↗

bioRxiv2022

Reliable one-step assessment of IGHV mutational status and gene mutations in Chronic Lymphocytic Leukemia by capture-based high throughput sequencing.

Proper management of chronic lymphocytic leukemia (CLL) patients requiring therapy relies on two important prognostic and theranostic molecular features: respectively, the mutational status of tumoral cells immunoglobulin heavy chain variable domain (IGHV) and the characteristics of TP53. Both these (immuno)genetic analyses require multiple time-consuming amplification and sequencing techniques by Sanger or HTS. The capture-HTS technology, allowing to select regions of interest, represents an attractive alternative and has already been applied for the detection of clonality in lymphoproliferative disorders. Here, a single-step capture design was developed to concomitantly investigate for IGHV and TP53. This was applied to a training retrospective (n=14) and a validation prospective (n=91) cohorts of CLL patients. The training cohort demonstrated the robustness of the method by comparison with the classical Sanger sequencing technology (100% identical results) for the IGHV mutational status. This consistency was confirmed for the first 59 patients of the validation cohort. Overall, the IGHV status of whole population (n=103) was accurately identified. Simultaneously, deletion or mutations of TP53 were identified from the same capture-library and HTS-sequencing run for each patient. This novel approach provides, in a single assay, useful answers about the molecular landscape of CLL patients, allowing for a documented choice of therapy. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=115 SRC="FIGDIR/small/483581v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@91685forg.highwire.dtl.DTLVardef@5b47baorg.highwire.dtl.DTLVardef@c2286corg.highwire.dtl.DTLVardef@ebd413_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗