Nuclear DDX3 expression predicts poor outcome in colorectal and breast cancer

Purpose: DEAD box protein 3 (DDX3) is an RNA helicase with oncogenic properties that shuttles between the cytoplasm and nucleus. The majority of DDX3 is found in the cytoplasm, but a subset of tumors has distinct nuclear DDX3 localization of yet unknown biological significance. This study aimed to evaluate the significance of and mechanisms behind nuclear DDX3 expression in colorectal and breast cancer. Methods: Expression of nuclear DDX3 and the nuclear exporter chromosome region maintenance 1 (CRM1) was evaluated by immunohistochemistry in 304 colorectal and 292 breast cancer patient samples. Correlations between the subcellular localization of DDX3 and CRM1 and the difference in overall survival between patients with and without nuclear DDX3 were studied. In addition, DDX3 mutants were created for in vitro evaluation of the mechanism behind nuclear retention of DDX3. Results: DDX3 was present in the nucleus of 35% of colorectal and 48% of breast cancer patient samples and was particularly strong in the nucleolus. Nuclear DDX3 correlated with worse overall survival in both colorectal (hazard ratio [HR] 2.34, P<0.001) and breast cancer (HR 2.39, P=0.004) patients. Colorectal cancers with nuclear DDX3 expression more often had cytoplasmic expression of the nuclear exporter CRM1 (relative risk 1.67, P=0.04). In vitro analysis of DDX3 deletion mutants demonstrated that CRM1-mediated export was most dependent on the N-terminal nuclear export signal. Conclusion: Overall, we conclude that nuclear DDX3 is partially CRM1-mediated and predicts worse survival in colorectal and breast cancer patients, putting it forward as a target for therapeutic intervention with DDX3 inhibitors under development in these cancer types

Cryo-FIB Machining: An Alternative to TEM Cryo-Sections Cut with Diamonds?

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7-August 11, 201

Killer cell proteases can target viral immediate-early proteins to control human cytomegalovirus infection in a noncytotoxic manner.

Human cytomegalovirus (HCMV) is the most frequent viral cause of congenital defects and can trigger devastating disease in immune-suppressed patients. Cytotoxic lymphocytes (CD8+ T cells and NK cells) control HCMV infection by releasing interferon-γ and five granzymes (GrA, GrB, GrH, GrK, GrM), which are believed to kill infected host cells through cleavage of intracellular death substrates. However, it has recently been demonstrated that the in vivo killing capacity of cytotoxic T cells is limited and multiple T cell hits are required to kill a single virus-infected cell. This raises the question whether cytotoxic lymphocytes can use granzymes to control HCMV infection in a noncytotoxic manner. Here, we demonstrate that (primary) cytotoxic lymphocytes can block HCMV dissemination independent of host cell death, and interferon-α/β/γ. Prior to killing, cytotoxic lymphocytes induce the degradation of viral immediate-early (IE) proteins IE1 and IE2 in HCMV-infected cells. Intriguingly, both IE1 and/or IE2 are directly proteolyzed by all human granzymes, with GrB and GrM being most efficient. GrB and GrM cleave IE1 after Asp398 and Leu414, respectively, likely resulting in IE1 aberrant cellular localization, IE1 instability, and functional impairment of IE1 to interfere with the JAK-STAT signaling pathway. Furthermore, GrB and GrM cleave IE2 after Asp184 and Leu173, respectively, resulting in IE2 aberrant cellular localization and functional abolishment of IE2 to transactivate the HCMV UL112 early promoter. Taken together, our data indicate that cytotoxic lymphocytes can also employ noncytotoxic ways to control HCMV infection, which may be explained by granzyme-mediated targeting of indispensable viral proteins during lytic infection

Influence of carbon support surface modification on the performance of nickel catalysts in carbon dioxide hydrogenation

The interaction between metal nanoparticles and a support is of key importance in catalysis. In this study, we demonstrate that the introduction of oxygen- or nitrogen-containing support surface groups on a graphite nanoplatelet support influence the performance of nickel supported catalysts during CO2 hydrogenation. By careful design of the synthesis conditions, the Ni nanoparticle size of the fresh catalysts was not affected by the type of support surface groups. A combination of H2 chemisorption and high resolution TEM demonstrates that the available metal surface depends on the interaction with the carbon support. The amination treatment results in the weakest interaction between the Ni and the support, showing the highest initial Ni weight-based activity, although at the expense of nanoparticle stability. Hence initial enhancement in activity is not always optimal for long term catalysis. The use of carbon with a higher density of oxygen functional groups that are stable above 350 °C, is beneficial for preventing deactivation due to particle growth. Furthermore, small amounts of contaminants can have a substantial influence on the CH4 selectivity at low conversions

Cleavage of Notch1 by granzyme B disables its transcriptional activity

International audienceGranzyme-mediated cell death is the main pathway for cytotoxic lymphocytes to kill virus-infected and tumor cells. A major player in this process is granzyme B (GrB), which triggers apoptosis in both caspase-dependent and caspase-independent manners. A caspase-independent substrate of GrB is the highly conserved transmembrane receptor Notch1. The GrB cleavage sites in Notch1 and functional consequences of Notch1 cleavage by GrB were unknown. We confirmed that Notch1 is a direct and caspase-independent substrate of GrB. We demonstrate that GrB cleaved the intracellular Notch1 domain at least at two distinct aspartic acids D1860 and D1961. Granzyme B cleavage of Notch1 can occur in all subcellular compartments, during maturation of the receptor, at the membrane, and in the nucleus. GrB also displayed perforin-independent functions by cleaving the extracellular domain of Notch1. Overall, cleavage of Notch1 by GrB resulted in a loss of transcriptional activity, independent of Notch1 activation. We conclude that GrB disables Notch1 function, likely resulting in anti-cellular proliferation and cell death signals

Beschikbaarheid van vis voor visdieven rond Marker Wadden in juli 2020

In het kader van het Kennis- en Innovatieprogramma Marker Wadden (KIMA) is in juli 2020 onderzoek gedaan naar de foerageergebieden en prooikeuze van visdieven die broeden op Marker Wadden. In aanvulling op lopend onderzoek naar de voedselkeuze van visdieven in relatie tot het broedsucces was de belangrijkste onderzoeksvraag in dit project waar de belangrijkste foerageergebieden liggen en welke omstandigheden bepalen wanneer vis die geschikt is als prooi voor visdieven bereikbaar is voor visdieven. Hiertoe zijn drie tellingen vanuit een vliegtuig uitgevoerd waarbij de aantallen foeragerende visdieven werden genoteerd en waar mogelijk omstandigheden die van invloed zijn bij de keuze van de foerageergebieden, bijvoorbeeld de aanwezigheid van foeragerende aalscholvers en activiteiten van (vissers)schepen. Daarnaast zijn er in 3 perioden van 2-3 dagen vanaf een visserschip bemonsteringen uitgevoerd van potentiele prooivis voor visdieven. Hierbij werden met een fijnmazige broedkor bemonsteringen aan het wateroppervlak, halverwege de waterkolom en bij de bodem uitgevoerd in het zuidwestelijk IJsselmeer en oostelijk Markermeer. Ook werden aantallen foeragerende sterns geteld en waar mogelijk de prooikeuze vastgesteld aan de hand van foto’s die op locatie werden gemaakt. Visdieven bleken verspreid over het relatief troebele Markermeer (Secchi 0.3-1.0 m) te foerageren en volgden soms vrachtschepen. In het aanzienlijk helderder zuidwestelijke deel van het IJsselmeer (Secchi 1.0-3.0 m) bleken visdieven geconcentreerd in vaak grotere groepen tot maximaal 150 individuen te foerageren, niet zelden samen met foeragerende aalscholvers en futen. Ook werden foeragerende visdieven (ca 25% tijdens de tellingen) aangetroffen bij vissersschepen die aalfuiken leegden langs de Houtribdijk. In het open water van IJsselmeer en Markermeer werd hoofdzakelijk spiering aangetroffen als geschikte prooi en werden, met name op het IJsselmeer, veel visdieven met spiering waargenomen die richting de broedkolonies vlogen op Marker Wadden en Trintelzand. Daarnaast bleek driedoornige stekelbaars veelvuldig voor te komen in de bovenste waterlagen in het IJsselmeer en werd waargenomen dat visdieven die ook aten maar niet naar de broedkolonies brachten. Nabij vissersschepen en aalfuiken langs de dijk werd een aanzienlijk gevarieerder dieet waargenomen waaronder ook bodemsoorten als pos en zwartbekgrondel die naar alle waarschijnlijkheid afkomstig was uit bijvangst van aalfuiken. Waarnemingen in de foerageergebieden blijken daarmee belangrijke aanvullingen te leveren op waarnemingen aan het dieet in de broedkolonies en inzicht in de (grote) betekenis van interacties tussen visdieven, andere visetende watervogels als aalscholvers en futen, en menselijke activiteiten als scheepvaart en visserij

Spontaneous Formation of Micrometer-Size Inorganic Peapods

We show that polyoxometalate (ammonium phosphomolybdate) Keggin in aqueous dispersions upon sonication spontaneously transforms into micrometer-sized, peapod-shaped structures. The formation of these peapods is preceded by the generation of spherical aggregates. The particles have been characterized experimentally by time-resolved dynamic light scattering (DLS), transmission electron microscopy (TEM), and scanning TEM with a high-angle annular dark field detector (STEM-HAADF) for energy-dispersive X-ray (STEM/EDX) elemental analyses. A pathway for the phenomenon is proposed

Magnetic Petrology of Equatorial Atlantic Sediments: Electron Microscopic Results and their Environmental Magnetic Implications

International audienc