Study of o-glycan sialylation in c6 cultured glioma cells: Regulation of a β-galactoside α2,3 sialyltransferase activity by ca2+/calmodulin antagonists and phosphatase inhibitors

International audienc

Understanding Takeovers and Telestration in Laparoscopic Surgery to Inform Telementoring System Design

International audienceSurgery is primarily taught through mentoring, where an expert mentor supervises a mentee performing surgery, taking over when necessary. Telementoring systems aim to provide mentees with access to remote mentors, but the physical distance between mentors and mentees poses unique challenges to surgical training. We investigate the underlying needs leading to takeovers in onsite mentoring and assess mentors’ ability to fulfill address these needs remotely using existing telestration tools, namely pointers and drawings on shared views. Through interviews and workshops with expert surgeons, we find that (1) mentors take over to convey gestures related to instrument placement, tissue displacement, force, and movement, (2) mentors gather information about location of tissue, equipment, and instruments, as well as gesture constraints, and (3) surgeons judge telestration insufficient for these needs. Based on this gap between onsite mentoring practices and telementoring tools, we discuss novel tools to address these needs and their evaluation

Study of O-glycan sialylation in C6 cultured glioma cells: Evidence for post-translational regulation of Aβ-galactoside α2,3 sialyltransferase activity by N-glycosylation

International audienceWe have studied the Gal beta 1-3GalNAc-R alpha 2,3 sialyltransferase from C6 glioma cells transferring Neu5Ac from CMP-Neu5Ac onto O-glycans of glycoproteins. Using synchronized C6 glioma cells, we showed that the alpha 2,3 sialyltransferase activity was inhibited by tunicamycin to a greater extend than DNA and protein biosynthesis suggesting inhibition of N-glycosylation of this enzyme. Additional demonstration of N-glycosylation of the alpha 2,3 sialytransferase was provided through ConA-Sepharose binding. Treatment of partially purified alpha 2,3 sialytransferase by peptide-N-glycosidase F showed a significative inhibition demonstrating that N-glycan moiety is required for complete activity of the C6 glioma cell alpha 2,3 sialyltransferase

IL-36γ Is a Pivotal Inflammatory Player in Periodontitis-Associated Bone Loss

International audiencePeriodontitis is a prevalent chronic inflammatory disease due to the host response (IL-1β, IL-6, TNF-α and IL-17A) to oral bacteria such as Porphyromonas gingivalis. The newer members of the IL-1 family, IL-36s (IL-36α/IL-36β/IL-36γ/IL-36Ra/IL-38) are known to be involved in host defense against P. gingivalis in oral epithelial cells (OECs) and are considered as key inflammatory mediators in chronic diseases. The aim of this study was to investigate the potential role of IL-36s in periodontitis. We showed here that IL-36γ mRNA gingival expression is higher in periodontitis patients, whereas IL-36β and IL-36Ra mRNA expression are lower compared to healthy controls. Interestingly, the elevated IL-36γ expression in patients is positively correlated with the RANKL/OPG ratio, an index of bone resorption. In vitro, IL-36γ expression was induced through TLR2 activation in primary OECs infected with P. gingivalis but not in gingival fibroblasts, the most widespread cell type in gingival connective tissue. In OECs, recombinant IL-36γ enhanced the expression of inflammatory cytokines (IL-1β, IL-6, TNF-α and IL-36γ), of TLR2 and importantly, the RANKL/OPG ratio. These findings suggest that IL-36γ could be a pivotal inflammatory player in periodontitis by perpetuating gingival inflammation and its associated alveolar bone resorption and could be a relevant therapeutic target

Genetic susceptibility factors in familial nasopharyngeal carcinoma

Nasopharyngeal carcinoma is common in Southern China, Hong Kong, Taiwan and Southeast Asian countries. The current study was performed on an exceptionally large multiplex NPC family from Sarawak, Malaysia (denoted as JAQBAB family). We aimed to explore the segregation of deleterious mutation(s) or NPC risk- associated allele within the genomic segment shared identical by descent (IBD) between the affected individuals. Genome-wide SNP-array covering all somatic chromosomes were performed on 11 of the NPC patients and their first-degree family members. The kinship was assessed and pairwise IBD estimation between target individuals were performed. Haplotype phasing was also performed on certain region of interests. Whole-exome sequencing was performed to identify deleterious mutations. The highest IBD score was detected within chromosome 10. Analysis of the exome sequencing data, however, did not find any deleterious mutation within this region that was shared between individuals in the JAQBAB family. Highest IBD score at chromosome 6 was found within the major histocompatibility complex (MHC) region, supporting strong HLA-EBV-NPC association that has been reported in an earlier study. HLA deep sequence-based typing (SBT) and gene sequencing on the 11 NPC patient samples revealed that the segregation of HLA-A*27:07 allele was consistent with the haplotype phasing pattern. Our results suggest that HLA-A*24:07 may harbour the risk allele for NPC among the subjects. However, further analysis is required before any definitive conclusion can be made. Further studies on the HLA-A*24:07 sequence may reveal more specific variation within this gene that can be associated with NPC risk in this family. In addition, further studies on HLA-A and risk of NPC other Southeast-Asian populations may shed more understanding about the association between HLA-A*24:07 and sporadic NPC in this region of the world

Interleukin-33 and RANK-L Interplay in the Alveolar Bone Loss Associated to Periodontitis.

Chronic Periodontitis (CP) is an inflammatory disease of bacterial origin that results in alveolar bone destruction. Porphyromonas gingivalis (Pg), one of the main periopathogens, initiates an inflammatory cascade by host immune cells thereby increasing recruitment and activity of osteoclasts, the bone resorbing cells, through enhanced production of the crucial osteoclastogenic factor, RANK-L. Antibodies directed against some cytokines (IL-1β, IL-6 and TNF-α) failed to exhibit convincing therapeutic effect in CP. It has been suggested that IL-33, could be of interest in CP.the present study aims to analyze whether and how IL-33 and RANK-L and/or their interplay are involved in the bone destruction associated to CP.mRNAs and protein expressions of IL-33 and RANK-L were analyzed in healthy and CP human gingival samples by immunohistochemistry (IHC) and RT-qPCR. Murine experimental periodontitis (EP) was induced using Pg infected ligature and Pg free ligature around the first maxillary molar. Alveolar bone loss was recorded by μCT. Mouse gingival explants were stimulated for 24 hours with IL-33 and RANK-L mRNA expression investigated by RT-qPCR. Human oral epithelial cells were infected by Pg for 6, 12; 24 hours and IL-33 and RANK-L mRNA expressions were analyzed by RT-qPCR.IL-33 is overexpressed in gingival epithelial cells in human affected by CP as in the murine EP. In human as in murine gingival cells, RANK-L was independently induced by Pg and IL-33. We also showed that the Pg-dependent RANK-L expression in gingival epithelial cells occured earlier than that of IL-33.Our results evidence that IL-33 overexpression in gingival epithelial cells is associated with CP and may trigger RANK-L expression in addition to a direct effect of Pg. Finally, IL-33 may act as an extracellular alarmin (danger signal) showing proinflammatory properties in CP perpetuating bone resorption induced by Pg infection

Integrative Genome-Wide Gene Expression Profiling of Clear Cell Renal Cell Carcinoma in Czech Republic and in the United States

<div><p>Gene expression microarray and next generation sequencing efforts on conventional, clear cell renal cell carcinoma (ccRCC) have been mostly performed in North American and Western European populations, while the highest incidence rates are found in Central/Eastern Europe. We conducted whole-genome expression profiling on 101 pairs of ccRCC tumours and adjacent non-tumour renal tissue from Czech patients recruited within the “K2 Study”, using the Illumina HumanHT-12 v4 Expression BeadChips to explore the molecular variations underlying the biological and clinical heterogeneity of this cancer. Differential expression analysis identified 1650 significant probes (fold change ≥2 and false discovery rate <0.05) mapping to 630 up- and 720 down-regulated unique genes. We performed similar statistical analysis on the RNA sequencing data of 65 ccRCC cases from the Cancer Genome Atlas (TCGA) project and identified 60% (402) of the downregulated and 74% (469) of the upregulated genes found in the K2 series. The biological characterization of the significantly deregulated genes demonstrated involvement of downregulated genes in metabolic and catabolic processes, excretion, oxidation reduction, ion transport and response to chemical stimulus, while simultaneously upregulated genes were associated with immune and inflammatory responses, response to hypoxia, stress, wounding, vasculature development and cell activation. Furthermore, genome-wide DNA methylation analysis of 317 TCGA ccRCC/adjacent non-tumour renal tissue pairs indicated that deregulation of approximately 7% of genes could be explained by epigenetic changes. Finally, survival analysis conducted on 89 K2 and 464 TCGA cases identified 8 genes associated with differential prognostic outcomes. In conclusion, a large proportion of ccRCC molecular characteristics were common to the two populations and several may have clinical implications when validated further through large clinical cohorts.</p> </div

Aires protégées, espaces durables ?

Autrefois enclaves marginales de protection de la nature, les aires protégées, apparues dès la fin du XIXe siècle, représentent aujourd’hui 12 % des surfaces émergées et concernent l’ensemble des territoires de la planète. Dans le contexte du développement durable, on attend à présent qu’elles répondent à la fois à des objectifs de conservation de la biodiversité et de développement social. La « durabilité » de ces espaces est en effet au cœur des politiques actuelles de gestion de l’environnement. Quelles sont, dans ce contexte, les nouvelles formes juridiques et territoriales des aires protégées ? Comment s’inscrivent-elles dans les infrastructures naturelles régionales et les réseaux écologiques transnationaux ? Quels outils de valorisation économique peuvent-elles offrir ? Autrement dit, dans quelle mesure les diverses aires protégées - parcs nationaux, réserves naturelles, réserves de biosphère, aires marines, corridors, terres indigènes, etc. - s’affirment-elles comme des espaces d’expérimentation du développement durable ? Pour répondre à ces questions, cet ouvrage alliant études régionales et globales analyse les tendances actuelles de la conservation. À travers le regard d’économistes, d’écologues, de juristes, d’anthropologues et de géographes, il propose une approche inédite des tensions qui se cristallisent autour d’une nature à réinventer

<i>Pg</i> infection increased the expression of RANK-L and IL-33 mRNAs in human oral epithelial cells.

<p>Human oral epithelial cells (OKF6/TERT2) were cultured with <i>Pg</i> at 10:1 or 100:1 MOI for 6, 12 or 24 hours. mRNAs encoding for IL-33 (A) and RANK-L ((B) were quantified by RT-qPCR. Three separate sets of experiment were performed. Data are shown as mean ± SEM. *p<0.05; **p<0.01.</p