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Ng H, Begum M, Chua GNL, Liu SX
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In Situ Nucleosome Assembly for Single-Molecule Correlative Force and ...

JOVE-JOURNAL OF VISUALIZED EXPERIMENTS 2024 SEP; ?(211):? Article e66579
Nucleosomes constitute the primary unit of eukaryotic chromatin and have been the focus of numerous informative single-molecule investigations regarding their biophysical properties and interactions with chromatin-binding proteins. Nucleosome reconstitution on DNA for these studies typically involves a salt dialysis procedure that provides precise control over the placement and number of nucleosomes formed along a DNA tether. However, this protocol is time-consuming and requires a substantial amount of DNA and histone octamers as inputs. To offer an alternative strategy, an in situ nucleosome reconstitution method for single-molecule force and fluorescence microscopy that utilizes the histone chaperone Nap1 is described. This method enables users to assemble nucleosomes on any DNA template without the need for strong nucleosome positioning sequences, adjust nucleosome density on demand, and use fewer reagents. In situ nucleosome formation occurs within seconds, offering a simpler experimental workflow and a convenient transition into single-molecule measurements. Examples of two downstream assays for probing nucleosome mechanics and visualizing the behavior of individual proteins on chromatin are further described.
Rodrigues FS, Karoutas A, Ruhland S, Rabas N, Rizou T, Di Blasio S, Ferreira ...
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Bidirectional activation of stem-like programs between metastatic cancer and ...

DEVELOPMENTAL CELL 2024 SEP 23; 59(18):?
A key step for metastatic outgrowth involves the generation of a deeply altered microenvironment (niche) that supports the malignant behavior of cancer cells. The complexity of the metastatic niche has posed a significant challenge in elucidating the underlying programs driving its origin. Here, by focusing on early stages of breast cancer metastasis to the lung in mice, we describe a cancer-dependent chromatin remodeling and activation of developmental programs in alveolar type 2 (AT2) cells within the niche. We show that metastatic cells can prime AT2 cells into a reprogrammed multilineage state. In turn, this cancer-induced reprogramming of AT2 cells promoted stem-like features in cancer cells and enhanced their initiation capacity. In conclusion, we propose the concept of "reflected stemness" as an early phenomenon during metastatic niche initiation, wherein metastatic cells reprogram the local tissue into a stem-like state that enhances intrinsic cancer-initiating potential, creating a positive feedback loop where tumorigenic programs are amplified.
Hayrapetyan A, Tumasyan A, Adam W, Andrejkovic JW, Arnold B, Bergauer H, Berg...
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Performance of the CMS electromagnetic calorimeter in pp collisions at √s<...

JOURNAL OF INSTRUMENTATION 2024 SEP; 19(9):? Article P09004
The operation and performance of the Compact Muon Solenoid (CMS) electromagnetic calorimeter (ECAL) are presented, based on data collected in pp collisions at root s = 13 TeV at the CERN LHC, in the years from 2015 to 2018 (LHC Run 2), corresponding to an integrated luminosity of 151 fb(-1). The CMS ECAL is a scintillating lead-tungstate crystal calorimeter, with a silicon strip preshower detector in the forward region that provides precise measurements of the energy and the time-of-arrival of electrons and photons. The successful operation of the ECAL is crucial for a broad range of physics goals, ranging from observing the Higgs boson and measuring its properties, to other standard model measurements and searches for new phenomena. Precise calibration, alignment, and monitoring of the ECAL response are important ingredients to achieve these goals. To face the challenges posed by the higher luminosity, which characterized the operation of the LHC in Run 2, the procedures established during the 2011-2012 run of the LHC have been revisited and new methods have been developed for the energy measurement and for the ECAL calibration. The energy resolution of the calorimeter, for electrons from Z boson decays reaching the ECAL without significant loss of energy by bremsstrahlung, was better than 1.8%, 3.0%, and 4.5% in the vertical bar eta vertical bar intervals [ 0.0, 0.8], [0.8, 1.5], [1.5, 2.5], respectively. This resulting performance is similar to that achieved during Run 1 in 2011-2012, in spite of the more severe running conditions.
Soula M, Unlu G, Welch R, Chudnovskiy A, Uygur B, Shah V, Alwaseem H, Bunk P,...
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Glycosphingolipid synthesis mediates immune evasion in KRAS-driven cancer

NATURE 2024 SEP 12; 633(8029):451-+
Cancer cells frequently alter their lipids to grow and adapt to their environment(1-3). Despite the critical functions of lipid metabolism in membrane physiology, signalling and energy production, how specific lipids contribute to tumorigenesis remains incompletely understood. Here, using functional genomics and lipidomic approaches, we identified de novo sphingolipid synthesis as an essential pathway for cancer immune evasion. Synthesis of sphingolipids is surprisingly dispensable for cancer cell proliferation in culture or in immunodeficient mice but required for tumour growth in multiple syngeneic models. Blocking sphingolipid production in cancer cells enhances the anti-proliferative effects of natural killer and CD8(+) T cells partly via interferon-gamma (IFN gamma) signalling. Mechanistically, depletion of glycosphingolipids increases surface levels of IFN gamma receptor subunit 1 (IFNGR1), which mediates IFN gamma-induced growth arrest and pro-inflammatory signalling. Finally, pharmacological inhibition of glycosphingolipid synthesis synergizes with checkpoint blockade therapy to enhance anti-tumour immune response. Altogether, our work identifies glycosphingolipids as necessary and limiting metabolites for cancer immune evasion.
Candeias C, Almeida ST, Paulo AC, Simoes AS, Ferreira B, Cruz AR, Queirós M, ...
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Streptococcus pneumoniae carriage, serotypes, genotypes, and antimicrobial re...

VACCINE 2024 SEP 17; 42(22):? Article 126219
Streptococcus pneumoniae carriage studies are crucial to monitor changes induced by use of pneumococcal conjugate vaccines and inform vaccination policies. In this cross-sectional study, we examined changes within the pneumococcal population following introduction of PCV13 in 2015 in the National Immunization Program (NIP), in Portugal. In 2018-2020 (NIP-PCV13), we obtained 1450 nasopharyngeal samples from children <= 6 years attending day-care. We assessed serotypes, antimicrobial resistance, and genotypes (MLST and GPSC) and compared findings with earlier periods: 2009-2010 (pre-PCV13), 2011-2012 (early-PCV13), and 2015-2016 (late-PCV13). Pneumococcal carriage prevalence remained stable at 60.2 %. Carriage of PCV13 serotypes was 10.7 %, markedly reduced compared to pre-PCV13 period (47.6 %). The most prevalent PCV13 serotypes were 19F, 3, and 19A all showing a significant decreasing trend compared to the pre-PCV13 period (from 7.1 % to 4.7 %, 10.1 % to 1.8 %, and 14.1 % to 1.8 %, respectively), a notable observation given the described limited effectiveness of PCV13 against serotype 3. Non-vaccinated children and children aged 4-6 years were more likely to carry PCV13 serotypes (2.5-fold, 95 %CI [1.1-5.6], and 2.9-fold, 95 %CI [1.3-6.8], respectively). The most prevalent non-PCV13 serotypes were 15B/C, 11A, 23B, 23A, and NT, collectively accounting for 51.9 % of all isolates. In total, 30.5 % of all pneumococci were potentially covered by PCV20. Resistance to penicillin (lowlevel) and macrolides increased significantly, from 9.3 % and 13.4 %, respectively, in the late-PCV13 period, to approximately 20 % each, mostly due to lineages expressing non-PCV13 serotypes, nearing pre-PCV13 levels. An expansion of lineages traditionally associated with PCV13 serotypes, like CC156-GPSC6 (serotype 14) and CC193-GPSC11 (serotype 19F), but now predominantly expressing non-PCV13 serotypes (11A, 15B/C, and 24F for GPSC6; and 15A and 21 for GPSC11) was noted. These findings indicate that the pneumococcal population is adapting to the pressures conferred by PCV13 and antimicrobial use and indicate the need to maintain close surveillance.
Braunscheidel KM, Voren G, Fowler CD, Lu Q, Kuryatov A, Cameron MD, Ibañez-Ta...
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SR9883 is a novel small-molecule enhancer of α4β2*nicotinic acetylcholine rec...

FRONTIERS IN MOLECULAR NEUROSCIENCE 2024 SEP 5; 17(?):? Article 1459098
Background Most smokers attempting to quit will quickly relapse to tobacco use even when treated with the most efficacious smoking cessation agents currently available. This highlights the need to develop effective new smoking cessation medications. Evidence suggests that positive allosteric modulators (PAM) and other enhancers of nicotinic acetylcholine receptor (nAChR) signaling could have therapeutic utility as smoking cessation agents.Methods 3-[3-(3-pyridyl)-1,2,4-oxadiazol-5-yl]benzonitrile (NS9283) was used as a starting point for medical chemistry efforts to develop novel small molecule enhancers of alpha 4 beta 2* nAChR stoichiometries containing a low-affinity agonist binding site at the interface of alpha 4/alpha 4 and alpha 4/alpha 5 subunits.Results The NS9283 derivative SR9883 enhanced the effect of nicotine on alpha 4 beta 2* nAChR stoichiometries containing low-affinity agonist binding sites, with EC50 values from 0.2-0.4 mu M. SR9883 had no effect on alpha 3 beta 2* or alpha 3 beta 4* nAChRs. SR9883 was bioavailable after intravenous (1 mg kg-1) and oral (10-20 mg kg-1) administration and penetrated into the brain. When administered alone, SR9883 (5-10 mg kg-1) had no effect on locomotor activity or intracranial self-stimulation (ICSS) thresholds in mice. When co-administered with nicotine, SR9883 enhanced locomotor suppression and elevations of ICSS thresholds induced by nicotine. SR9883 (5 and 10 mg kg-1) decreased responding for intravenous nicotine infusions (0.03 mg kg-1 per infusion) but had no effect on responding for food rewards in rats.Conclusions These data suggest that SR9883 is useful for investigating behavioral processes regulated by certain alpha 4 beta 2* nAChR stoichiometries. SR9883 and related compounds with favorable drug-like physiochemical and pharmacological properties hold promise as novel treatments of tobacco use disorder.
Potapov V, Krudup S, Maguire S, Unlu I, Guan SX, Buss JA, Smail BA, van Eeuwe...
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Discrete measurements of RNA polymerase and reverse transcriptase fidelity re...

RNA 2024 SEP; 30(9):1246-1258
Direct methods for determining the fidelity of DNA polymerases are robust, with relatively little sample manipulation before sequencing. In contrast, methods for measuring RNA polymerase and reverse transcriptase fidelities are complicated by additional preparation steps that introduce ambiguity and error. Here, we describe a sequencing method, termed Roll-Seq, for simultaneously determining the individual fidelities of RNA polymerases and reverse transcriptases (RT) using Pacific Biosciences single molecule real-time sequencing. By using reverse transcriptases with high rolling-circle activity, Roll-Seq generates long concatemeric cDNA from a circular RNA template. To discern the origin of a mutation, errors are recorded and determined to occur within a single concatemer (reverse transcriptase error) or all concatemers (RNA polymerase error) over the cDNA strand. We used Roll-Seq to measure the fidelities of T7 RNA polymerases, a Group II intron-encoded RT (Induro), and two LINE RTs (Fasciolopsis buski R2-RT and human LINE-1). Substitution rates for Induro and R2-RT are the same for cDNA and second-strand synthesis while LINE-1 has 2.5-fold lower fidelity when performing second-strand synthesis. Deletion and insertion rates increase for all RTs during second-strand synthesis. In addition, we find that a structured RNA template impacts fidelity for both RNA polymerase and RT. The accuracy and precision of Roll-Seq enable this method to be applied as a complementary analysis to structural and mechanistic characterization of RNA polymerases and reverse transcriptases or as a screening method for RNAP and RT fidelity.
Hayrapetyan A, Tumasyan A, Adam W, Andrejkovic JW, Bergauer T, Chatterjee S, ...
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Search for bottom-type vectorlike quark pair production in dileptonic and ful...

PHYSICAL REVIEW D 2024 SEP 17; 110(5):? Article 052004
A search is described for the production of a pair of bottom-type vectorlike quarks (B VLQs) with mass greater than 1000 GeV. Each B VLQ decays into a b quark and a Higgs boson, a b quark and a Z boson, or a t quark and a W boson. This analysis considers both fully hadronic final states and those containing a charged lepton pair from a Z boson decay. The products of the H -> bb boson decay and of the hadronic Z or W boson decays can be resolved as two distinct jets or merged into a single jet, so the final states are classified by the number of reconstructed jets. The analysis uses data corresponding to an integrated luminosity of 138 fb(-1) collected in proton-proton collisions at root s = 13 TeV with the CMS detector at the LHC from 2016 to 2018. No excess over the expected background is observed. Lower limits are set on the B VLQ mass at the 95% confidence level. These depend on the B VLQ branching fractions and are 1570 and 1540 GeV for 100% B -> bH and 100% B -> bZ, respectively. In most cases, the mass limits obtained exceed previous limits by at least 100 GeV.
Le Pen J, Paniccia G, Kinast V, Moncada-Velez M, Ashbrook AW, Bauer M, Hoffma...
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A genome-wide arrayed CRISPR screen identifies PLSCR1 as an intrinsic barrier...

PLOS BIOLOGY 2024 SEP; 22(9):? Article e3002767
Interferons (IFNs) play a crucial role in the regulation and evolution of host-virus interactions. Here, we conducted a genome-wide arrayed CRISPR knockout screen in the presence and absence of IFN to identify human genes that influence Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection. We then performed an integrated analysis of genes interacting with SARS-CoV-2, drawing from a selection of 67 large-scale studies, including our own. We identified 28 genes of high relevance in both human genetic studies of Coronavirus Disease 2019 (COVID-19) patients and functional genetic screens in cell culture, with many related to the IFN pathway. Among these was the IFN-stimulated gene PLSCR1. PLSCR1 did not require IFN induction to restrict SARS-CoV-2 and did not contribute to IFN signaling. Instead, PLSCR1 specifically restricted spike-mediated SARS-CoV-2 entry. The PLSCR1-mediated restriction was alleviated by TMPRSS2 overexpression, suggesting that PLSCR1 primarily restricts the endocytic entry route. In addition, recent SARS-CoV-2 variants have adapted to circumvent the PLSCR1 barrier via currently undetermined mechanisms. Finally, we investigate the functional effects of PLSCR1 variants present in humans and discuss an association between PLSCR1 and severe COVID-19 reported recently. Interferons (IFNs) have a role in the regulation of virus-host interactions. This study uses genome-wide CRISPR knockout screen data to identify 28 genes that impact SARS-CoV-2 infection, including PLSCR1, which restricts spike-mediated SARS-CoV-2 entry independently of its IFN-related role.
El Kettani A, Ouair H, Marnissi F, El Bakkouri J, Chevalier R, Lorenzo L, Kho...
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Case Report of Two Independent Moroccan Families with Syndromic Epidermodyspl...

VIRUSES-BASEL 2024 SEP; 16(9):? Article 1415
Epidermodysplasia verruciformis (EV) is a rare genodermatosis caused by beta-human papillomaviruses (HPV) in immunodeficient patients. EV is characterized by flat warts and pityriasis-like lesions and might be isolated or syndromic, associated with some other infectious manifestations. We report here three patients from two independent families, with syndromic EV for both of them. By whole exome sequencing, we found that the patients carry new homozygous variants in STK4, both leading to a premature stop codon. STK4 deficiency causes a combined immunodeficiency characterized by a broad infectious susceptibility to bacteria, viruses, and fungi. Auto-immune manifestations were also reported. Deep immunophenotyping revealed multiple cytopenia in the three affected patients, in particular deep CD4(+) T cells deficiency. We report here the fourth and the fifth cases of the syndromic EV due to STK4 deficiency.