Survival advantages conferred to colon cancer cells by E-selectin-induced activation of the PI3K-NFκB survival axis downstream of Death receptor-3

International audienceABSTRACT: BACKGROUND: Extravasation of circulating cancer cells is a key event of metastatic dissemination that is initiated by the adhesion of cancer cells to endothelial cells. It requires interactions between adhesion receptors on endothelial cells and their counter-receptors on cancer cells. Notably, E-selectin, a major endothelial adhesion receptor, interacts with Death receptor-3 present on metastatic colon carcinoma cells. This interaction confers metastatic properties to colon cancer cells by promoting the adhesion of cancer cells to endothelial cells and triggering the activation of the pro-migratory p38 and pro-survival ERK pathways in the cancer cells. In the present study, we investigated further the mechanisms by which the E-selectin-activated pathways downstream of DR3 confer a survival advantage to colon cancer cells. METHODS: Cell survival has been ascertained by using the WST-1 assay and by evaluating the activation of the PI3 kinase/NFκB survival axis. Apoptosis has been assayed by determining DNA fragmentation by Hoechst staining and by measuring cleavage of caspases-8 and -3. DR3 isoforms have been identified by PCR. For more precise quantification, targeted PCR reactions were carried out, and the amplified products were analyzed by automated chip-based microcapillary electrophoresis on an Agilent 2100 Bioanalyzer instrument. RESULTS: Interaction between DR3-expressing HT29 colon carcinoma cells and E-selectin induces the activation of the PI3K/Akt pathway. Moreover, p65/RelA, the anti-apoptotic subunit of NFκB, is rapidly translocated to the nucleus in response to E-selectin. This translocation is impaired by the PI3K inhibitor LY294002. Furthermore, inhibition of the PI3K/Akt pathway increases the cleavage of caspase 8 in colon cancer cells treated with E-selectin and this effect is still further increased when both ERK and PI3K pathways are concomitantly inhibited. Intriguingly, metastatic colon cancer cell lines such as HT29 and SW620 express higher levels of a splice variant of DR3 that has no trans-membrane domain and no death domain. CONCLUSION: Colon cancer cells acquire an increased capacity to survive via the activation of the PI3K/NFκB pathway following the stimulation of DR3 by E-selectin. Generation of a DR3 splice variant devoid of death domain can further contribute to protect against apoptosis

Metabolic Control within the Jasmonate Biochemical Pathway

International audienc

Cyberlindnera jadinii and Kluyveromyces lactis, two fungi used in food processes, have potential probiotic effects on gut inflammation

International audienceMany strains have been used and selected by the food industry for their capacities to ferment, produce flavors, or produce heterologous molecules. Very little is known about the diversity of foodborne yeasts and their potential effect on gut microbiota and gut health. We initiated a complete characterization of five strains belonging to five species with a long history of safe use in food: Cyberlindnera jadinii, Debaryomyces hansenii, Kazachstania unispora, Kluyveromyces lactis, and Pichia membra nifaciens, with a focus on their capacity to protect against gut inflammation using an in vivo dextran sodium sulfate-induced colitis model in mice. C. jadinii and K. lactis living cells showed a clear reduction in mouse sensitivity to colitis in vivo. Interestingly, we observed that C. jadinii had the capacity to survive transit in the gut, while K. lactis did not. We demonstrated that C. jadinii was unable to efficiently adhere to epithelial cells and did not survive more than 24 to 48 h in the gut. Transcriptomic analysis using NanoString technology suggested a potential role of IL-8 through Mif and Fkbp5 in the effect of C. jadinii on the immune system. Bacterial and fungal microbiota characterization showed a modification of both microbiota after C. jadinii treatment, with a significant increase in positive microorganisms and a decrease in pathobionts. Altogether, these data suggest that both C. jadinii and K. lactis strains have potential as probiotic yeast strains to fight against inflammation in the gut, but further studies are needed to understand the mechanisms by which these strains act on gut health

Conception d'un moniteur faisceau basé sur l'utilisation de détecteurs diamants pour le contrôle en ligne de faisceaux pulsés

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Développement de moniteurs faisceaux en technologie diamant pour le monitorage de radiothérapies innovantes : hadronthérapie et thérapies "flash"

National audienceAu cours d’une séance d’irradiation en hadronthérapie, une partie des ions incidents va subir des réactions de fragmentations nucléaires qui ont pour effet de délocaliser le dépôt de dose dans le patient. C’est donc une source d’incertitude qui peut nuire à une délivrance optimale des traitements.La collaboration Clarys (IP2I CPPM LPSC CREATIS) met au point un système de contrôle en ligne basé sur la détection de gamma prompts émis le long du parcours des ions. Afin de réaliser une mesure de temps de vol absolue (ion + gamma prompt), ClaRys inclut dans son projet le développement d’un hodoscope de marquage de faisceau installé en amont du patient. Il est destiné à fournir une information temporelle et spatiale des ions entrants. Ces informations peuvent être utilisées pour le processus de reconstruction d'image et dans la réduction des bruits de fond.Un premier hodoscope basé sur un maillage de fibres scintillantes lues par des photo-multiplicateurs (PM) a été développé. En raison des limitations du taux de comptage des PM, l'efficacité de détection de l'hodoscope à fibres diminue pour les courants de faisceau élevés. Ces limitations ont conduit au développement d'un hodoscope à base de diamant synthétiques (croissance par dépôt chimique en phase vapeur ou CVD).Les qualités intrinsèques du diamant (rapidité, faible courant de fuite, excellent rapport signal sur bruit, résistance aux radiations, équivalence tissu humain) font de ce semi-conducteur un parfait candidat pour répondre aux exigences de monitorage. L'hodoscope diamant devrait permettre d'atteindre des résolutions temporelles de 100 ps qui vont au-delà des performances de l’hodoscope à fibres et permettrait de faire de l’Ultra Fast Timing cela constitue le projet ClaRys-UFT.Par ailleurs, la radiothérapie innovante «flash» qui permet de délivrer des faisceaux pendant un temps ultracourt (quelques millièmes de secondes au lieu de plusieurs minutes pour la radiothérapie conventionnelle) requiert un monitorage spécifique de faisceaux en mode pulsé. La rapidité des détecteurs diamants constitue là un atout essentiel pour un tel développement avec une capacité de marquage en temps « début » et « fin » des paquets des trains d’impulsions ainsi que de comptage des particules dans le train à haute intensité faisceau. Cela a conduit au développement du moniteur faisceau diamant DIAMMONI dans le cadre du projet R&T IN2P3 DIAMTECH (collaboration LPSC SUBATECH ARRONAX)

Diamond-based detector development for pulsed beam monitoring for medical applications

VirtualInternational audienceDevelopment of new generations of ion accelerators:•medical applications: hadrontherapy, X-ray or synchrotron radiation therapy and flash therapyvery precise monitoring of the beam with rapid counting in a high lyradiative environment.The intrinsic qualities of diamond:•speed, low leakage current, excellent SNR, resistance to radiationan excellent candidate to meet such monitoring requirements over a wide dynamic range from a fraction of pA (single particle) up to μA

Cephalopods in neuroscience: regulations, research and the 3Rs

Cephalopods have been utilised in neurosci- ence research for more than 100 years particularly because of their phenotypic plasticity, complex and centralised nervous system, tractability for studies of learning and cellular mechanisms of memory (e.g. long-term potentia- tion) and anatomical features facilitating physiological studies (e.g. squid giant axon and synapse). On 1 January 2013, research using any of the about 700 extant species of ‘‘live cephalopods’’ became regulated within the European Union by Directive 2010/63/EU on the ‘‘Protection of Animals used for Scientific Purposes’’, giving cephalopods the same EU legal protection as previously afforded only to vertebrates. The Directive has a number of implications, particularly for neuroscience research. These include: (1) projects will need justification, authorisation from local competent authorities, and be subject to review including a harm-benefit assessment and adherence to the 3Rs princi- ples (Replacement, Refinement and Reduction). (2) To support project evaluation and compliance with the new EU law, guidelines specific to cephalopods will need to be developed, covering capture, transport, handling, housing, care, maintenance, health monitoring, humane anaesthesia, analgesia and euthanasia. (3) Objective criteria need to be developed to identify signs of pain, suffering, distress and lasting harm particularly in the context of their induction by an experimental procedure. Despite diversity of views existing on some of these topics, this paper reviews the above topics and describes the approaches being taken by the cephalopod research community (represented by the authorship) to produce ‘‘guidelines’’ and the potential contribution of neuroscience research to cephalopod welfare

Cryptococcus neoformans Infections Differ Among Human Immunodeficiency Virus (HIV)–Seropositive and HIV-Seronegative Individuals: Results From a Nationwide Surveillance Program in France

International audienceAmong 1107 cryptococcosis cases from the French surveillance network (2005–2020), the proportion of HIV-seronegative individuals has recently surpassed that of HIV-seropositive individuals. We observed marked differences in patient characteristics, disease presentations, cryptococcal antigen results, infecting species, and mortality according to HIV serostatus

Rare predicted loss-of-function variants of type I IFN immunity genes are associated with life-threatening COVID-19

BackgroundWe previously reported that impaired type I IFN activity, due to inborn errors of TLR3- and TLR7-dependent type I interferon (IFN) immunity or to autoantibodies against type I IFN, account for 15-20% of cases of life-threatening COVID-19 in unvaccinated patients. Therefore, the determinants of life-threatening COVID-19 remain to be identified in similar to 80% of cases.MethodsWe report here a genome-wide rare variant burden association analysis in 3269 unvaccinated patients with life-threatening COVID-19, and 1373 unvaccinated SARS-CoV-2-infected individuals without pneumonia. Among the 928 patients tested for autoantibodies against type I IFN, a quarter (234) were positive and were excluded.ResultsNo gene reached genome-wide significance. Under a recessive model, the most significant gene with at-risk variants was TLR7, with an OR of 27.68 (95%CI 1.5-528.7, P=1.1x10(-4)) for biochemically loss-of-function (bLOF) variants. We replicated the enrichment in rare predicted LOF (pLOF) variants at 13 influenza susceptibility loci involved in TLR3-dependent type I IFN immunity (OR=3.70[95%CI 1.3-8.2], P=2.1x10(-4)). This enrichment was further strengthened by (1) adding the recently reported TYK2 and TLR7 COVID-19 loci, particularly under a recessive model (OR=19.65[95%CI 2.1-2635.4], P=3.4x10(-3)), and (2) considering as pLOF branchpoint variants with potentially strong impacts on splicing among the 15 loci (OR=4.40[9%CI 2.3-8.4], P=7.7x10(-8)). Finally, the patients with pLOF/bLOF variants at these 15 loci were significantly younger (mean age [SD]=43.3 [20.3] years) than the other patients (56.0 [17.3] years; P=1.68x10(-5)).ConclusionsRare variants of TLR3- and TLR7-dependent type I IFN immunity genes can underlie life-threatening COVID-19, particularly with recessive inheritance, in patients under 60 years old