Aggregation of Lipid Rafts Accompanies Signaling via the T Cell Antigen Receptor

The role of lipid rafts in T cell antigen receptor (TCR) signaling was investigated using fluorescence microscopy. Lipid rafts labeled with cholera toxin B subunit (CT-B) and cross-linked into patches displayed characteristics of rafts isolated biochemically, including detergent resistance and colocalization with raft-associated proteins. LCK, LAT, and the TCR all colocalized with lipid patches, although TCR association was sensitive to nonionic detergent. Aggregation of the TCR by anti-CD3 mAb cross-linking also caused coaggregation of raft-associated proteins. However, the protein tyrosine phosphatase CD45 did not colocalize to either CT-B or CD3 patches. Cross-linking of either CD3 or CT-B strongly induced tyrosine phosphorylation and recruitment of a ZAP-70(SH2)2–green fluorescent protein (GFP) fusion protein to the lipid patches. Also, CT-B patching induced signaling events analagous to TCR stimulation, with the same dependence on expression of key TCR signaling molecules. Targeting of LCK to rafts was necessary for these events, as a nonraft- associated transmembrane LCK chimera, which did not colocalize with TCR patches, could not reconstitute CT-B–induced signaling. Thus, our results indicate a mechanism whereby TCR engagement promotes aggregation of lipid rafts, which facilitates colocalization of LCK, LAT, and the TCR whilst excluding CD45, thereby triggering protein tyrosine phosphorylation

A Photoredox Coupling Reaction of Benzylboronic Esters and Carbonyl Compounds in Batch and Flow.

Mild cross-coupling reaction between benzylboronic esters with carbonyl compounds and some imines was achieved under visible-light-induced iridium-catalyzed photoredox conditions. Functional group tolerance was demonstrated by 51 examples, including 13 heterocyclic compounds. Gram-scale reaction was realized through the use of computer-controlled continuous flow photoreactors.Uniqsis Ltd and Mark Ladlow for the generous loan 236 of a Photosyn reactor. Y.C. thanks Pfizer for funding the 237 postdoctoral fellowship. The authors also gratefully acknowl- 238 edge financial support from H2020-FETOPEN-2016-2017 239 program of European commission (S.V.L.; grant agreement 240 no.: 737266-ONE FLOW)

TPL-2 restricts Ccl24-dependent immunity to Heligmosomoides polygyrus

Funding: This work was supported by the Francis Crick Institute which receives its core funding from Cancer Research UK (FC001220), the UK Medical Research Council (FC001220), and the Wellcome Trust (FC001200). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Acknowledgments We are indebted to The Francis Crick Institute Flow Cytometry facility, and in particular Bhavik Patel, Graham Preece, Wayne Turnbull and Phil Hobson. We would also like to thank The Francis Crick Institute Procedural Service Section for production of GA lines and Biological Services, especially Trisha Norton, Keith Williams and Adebambo Adekoya for animal husbandry and technical support; to Riccardo Guidi for constructive discussions and technical assistance. We would like to thank Gitta Stockinger and AhR Immunity Laboratory for providing technical support and reagents throughout this study. We also thank Richard Rance and the Wellcome Trust Sanger Institute’s 454 pyrosequencing team for generating 16S rRNA gene data.Peer reviewedPublisher PD

Visible-Light-Mediated Annulation of Electron-Rich Alkenes and Nitrogen-Centered Radicals from N-Sulfonylallylamines: Construction of Chloromethylated Pyrrolidine Derivatives.

A visible-light-mediated annulation of N-sulfonylallylamines and olefins is reported. Rapid access to highly functionalized chloromethylated pyrrolidines can be achieved using mild conditions for the generation of nitrogen-centered radicals. Both a transition-metal-based catalyst and an organic dye can be used as photosensitizers with 0.5 mol % loading. The reaction was found to be applicable to a large variety of electron-rich and electron-neutral olefins.This work was supported by a postdoctoral fellowship from Pfizer (L.C. and A.G.) and the EPSRC Grants EP/K009494/1 and EP/M004120/1 (S.V.L.)

Ebola virus VP35 induces high-level production of recombinant TPL-2–ABIN-2–NF-κB1 p105 complex in co-transfected HEK-293 cells

Activation of PKR (double-stranded-RNA-dependent protein kinase) by DNA plasmids decreases translation, and limits the amount of recombinant protein produced by transiently transfected HEK (human embryonic kidney)-293 cells. Co-expression with Ebola virus VP35 (virus protein 35), which blocked plasmid activation of PKR, substantially increased production of recombinant TPL-2 (tumour progression locus 2)–ABIN-2 [A20-binding inhibitor of NF-κB (nuclear factor κB) 2]–NF-κB1 p105 complex. VP35 also increased expression of other co-transfected proteins, suggesting that VP35 could be employed generally to boost recombinant protein production by HEK-293 cells

One-Pot Acid-Catalyzed Ring-Opening/Cyclization/Oxidation of Aziridines with N-Tosylhydrazones: Access to 1,2,4-Triazines

A new, three-step, telescoped reaction sequence for the regioselective conversion of N-tosyl hydrazones and aziridines to 3,6-disubstituted and 3,5,6-trisubstituted 1,2,4-triazines is described. The process involves an efficient nucleophilic ring opening of the aziridine, giving access to a wide range of aminohydrazones, isolated with excellent yields. A “one-pot” procedure, combining the ring opening with a cyclization and an oxidation step, allows the preparation of diversified triazines in good yields.This work was supported by a postdoctoral fellowship from Pfizer (L.C.) and EPSRC Grant Nos. EP/K009494/1 and EP/M004120/1 (S.V.L.). We also thank Dr. Andrew D. Bond for conducting X-ray crystallographic analysis

Photochemical Homologation for the Preparation of Aliphatic Aldehydes in Flow

Cheap and readily available aqueous formaldehyde was used as a formylating reagent in a homologation reaction with nonstabilized diazo compounds, enabled by UV photolysis of bench-stable oxadiazolines in a flow photoreactor. Various aliphatic aldehydes were synthesized along with the corresponding derivatized alcohols and benzimidazoles. No transition-metal catalyst or additive was required to affect the reaction, which proceeded at room temperature in 80 min.</p

Design, Synthesis, and Evaluation of Tetrasubstituted Pyridines as Potent 5-HT2C Receptor Agonists.

A series of pyrido[3,4-d]azepines that are potent and selective 5-HT2C receptor agonists is disclosed. Compound 7 (PF-04781340) is identified as a suitable lead owing to good 5-HT2C potency, selectivity over 5-HT2B agonism, and in vitro ADME properties commensurate with an orally available and CNS penetrant profile. The synthesis of a novel bicyclic tetrasubstituted pyridine core template is outlined, including rationale to account for the unexpected formation of aminopyridine 13 resulting from an ammonia cascade cyclization.We would like to thank the EPSRC (SVL, grant nº EP/K0099494/1 and nº EP/K039520/1) for financial support.This is the accepted manuscript. The final version is available from ACS at http://pubs.acs.org/doi/abs/10.1021/ml500507v

NF-κB1 Inhibits TLR-Induced IFN-β Production in Macrophages Through TPL-2-dependent ERK Activation

available in PMC 2012 February 15.Although NF-κB1 p50/p105 has critical roles in immunity, the mechanism by which NF-κB1 regulates inflammatory responses is unclear. In this study, we analyzed the gene expression profile of LPS-stimulated Nfkb1−/− macrophages that lack both p50 and p105. Deficiency of p50/p105 selectively increased the expression of IFN-responsive genes, which correlated with increased IFN-β expression and STAT1 phosphorylation. IFN Ab-blocking experiments indicated that increased STAT1 phosphorylation and expression of IFN-responsive genes observed in the absence of p50/p105 depended upon autocrine IFN-β production. Markedly higher serum levels of IFN-β were observed in Nfkb1−/− mice than in wild-type mice following LPS injection, demonstrating that Nfkb1 inhibits IFN-β production under physiological conditions. TPL-2, a mitogen-activated protein kinase kinase kinase stabilized by association with the C-terminal ankyrin repeat domain of p105, negatively regulates LPS-induced IFN-β production by macrophages via activation of ERK MAPK. Retroviral expression of TPL-2 in Nfkb1−/− macrophages, which are deficient in endogenous TPL-2, reduced LPS-induced IFN-β secretion. Expression of the C-terminal ankyrin repeat domain of p105 in Nfkb1−/− macrophages, which rescued LPS activation of ERK, also inhibited IFN-β expression. These data indicate that p50/p105 negatively regulates LPS-induced IFN signaling in macrophages by stabilizing TPL-2, thereby facilitating activation of ERK.National Institutes of Health (U.S.) (NIH AI52267)National Institutes of Health (U.S.) (NIH CA108854)National Institutes of Health (U.S.) (NIH CA67529)Medical Research Council (Great Britain