Strongly interacting electrons can exhibit novel collective phases, among which the electronic nematic phases are perhaps the most surprising as they spontaneously break rotational symmetry of the underlying crystal lattice.1 The electron nematicity has been recently observed in the iron-pnictide 2-6 and cuprate 7-9 hightemperature superconductors. Whether such a tendency of electrons to self-organise unidirectionally has a common feature in these superconductors is, however, a highly controversial issue. In the cuprates, the nematicity has been suggested as a possible source of the pseudogap phase, 7-9 whilst in the iron-pnictides, it has been commonly associated with the tetragonalto-orthorhombic structural phase transition at T s . Here, we provide the first thermodynamic evidence in BaFe 2 (As 1−x P x ) 2 that the nematicity develops well above the structural transition and persists to the nonmagnetic superconducting regime, resulting in a new phase diagram strikingly similar to the pseudogap phase diagram in the cuprates.9,10 Our highly sensitive magnetic anisotropy measurements using microcantilever torque-magnetometry under in-plane field rotation reveal pronounced two-fold oscillations, which break the tetragonal symmetry. Combined with complementary high-resolution synchrotron X-ray and resistivity measurements, our results consistently identify two distinct temperaturesone at T * , signifying a true nematic transition, and the other at T s (< T * ), which we show to be not a true phase transition, but rather what we refer to as a "meta-nematic transition", in analogy to the well-known metamagnetic transition in the theory of magnetism. Our observation of the extended nematic phase above the superconducting dome establishes that the nematicity has primarily an electronic origin, inherent in the normal state of high-temperature superconductors.In the iron pnictides, the antiferromagnetic transition is closely intertwined with the structural phase transition from tetragonal (T) to orthorhombic (O) crystal symmetry. Although recent experiments, including neutron scattering, 2 ARPES, 3,11 STM, 4 and transport measurements, 5,6 have provided evidence for electronic anisotropy, these measurements were carried out either in the low-temperature orthorhombic phase, 2,4,11 where the crystal lattice structure has already broken C 4 symmetry, or in the tetragonal phase under uniaxial strain 3,5,6 that also breaks this symmetry. Therefore, the question remains open whether the electronic anisotropy can exist above the structural transition without an external driving force, including under the superconducting (SC) dome. In the past, the nematic transition in the pnictides has been associated either with the orbital ordering, [12][13][14][15][16][17][18] or with the spontaneous breaking of the Z 2 Ising symmetry between two collinear magnetic ordering wave-vectors Q = (π, 0) and (0, π).19-22 Therefore determining the nature of the nematicity is a key to understanding the microscopic origin of the lattice and magnetic...

The NLRP3 inflammasome responds to microbes and danger signals by processing and activating proinflammatory cytokines including IL-1β and IL-18. We show that NLRP3 inflammasome activation is restricted to interphase of the cell cycle by NEK7, a serine/threonine kinase previously implicated in mitosis. NLRP3 inflammasome activation requires NEK7, which binds to the NLRP3 leucine-rich repeat domain in a kinase-independent manner downstream from the induction of mitochondrial ROS. This interaction is necessary for NLRP3-ASC complex formation, ASC oligomerization, and caspase-1 activation. NEK7 promotes the NLRP3-dependent cellular inflammatory response to intraperitoneal monosodium urate challenge, and the development of experimental autoimmune encephalitis in mice. Our findings suggest NEK7 serves as a cellular switch that enforces mutual exclusivity between the inflammasome response and cell division.

A second-order phase transition is characterized by spontaneous symmetry breaking. The nature of the broken symmetry in the so-called "hidden-order" phase transition in the heavy-fermion compound URu(2)Si(2), at transition temperature T(h) = 17.5 K, has posed a long-standing mystery. We report the emergence of an in-plane anisotropy of the magnetic susceptibility below T(h), which breaks the four-fold rotational symmetry of the tetragonal URu(2)Si(2). Two-fold oscillations in the magnetic torque under in-plane field rotation were sensitively detected in small pure crystals. Our findings suggest that the hidden-order phase is an electronic "nematic" phase, a translationally invariant metallic phase with spontaneous breaking of rotational symmetry.

Imiquimod is a small-molecule ligand of Toll-like receptor-7 (TLR7) that is licensed for the treatment of viral infections and cancers of the skin. Imiquimod has TLR7-independent activities that are mechanistically unexplained, including NLRP3 inflammasome activation in myeloid cells and apoptosis induction in cancer cells. We investigated the mechanism of inflammasome activation by imiquimod and the related molecule CL097 and determined that K efflux was dispensable for NLRP3 activation by these compounds. Imiquimod and CL097 inhibited the quinone oxidoreductases NQO2 and mitochondrial Complex I. This induced a burst of reactive oxygen species (ROS) and thiol oxidation, and led to NLRP3 activation via NEK7, a recently identified component of this inflammasome. Metabolic consequences of Complex I inhibition and endolysosomal effects of imiquimod might also contribute to NLRP3 activation. Our results reveal a K efflux-independent mechanism for NLRP3 activation and identify targets of imiquimod that might be clinically relevant.

With the wide availability of massively parallel sequencing technologies, genetic mapping has become the rate limiting step in mammalian forward genetics. Here we introduce a method for real-time identification of N-ethyl-N-nitrosourea-induced mutations that cause phenotypes in mice. All mutations are identified by whole exome G1 progenitor sequencing and their zygosity is established in G2/G3 mice before phenotypic assessment. Quantitative and qualitative traits, including lethal effects, in single or multiple combined pedigrees are then analyzed with Linkage Analyzer, a software program that detects significant linkage between individual mutations and aberrant phenotypic scores and presents processed data as Manhattan plots. As multiple alleles of genes are acquired through mutagenesis, pooled "superpedigrees" are created to analyze the effects. Our method is distinguished from conventional forward genetic methods because it permits (1) unbiased declaration of mappable phenotypes, including those that are incompletely penetrant (2), automated identification of causative mutations concurrent with phenotypic screening, without the need to outcross mutant mice to another strain and backcross them, and (3) exclusion of genes not involved in phenotypes of interest. We validated our approach and Linkage Analyzer for the identification of 47 mutations in 45 previously known genes causative for adaptive immune phenotypes; our analysis also implicated 474 genes not previously associated with immune function. The method described here permits forward genetic analysis in mice, limited only by the rates of mutant production and screening.N-ethyl-N-nitrosourea | genetic mapping | forward genetics | mutagenesis | massively parallel sequencing P henotypic variation in mice can be induced with N-ethyl-Nnitrosourea (ENU), which creates single base pair substitutions in germ line DNA. However, the positional cloning of ENU-induced mutations causative for phenotypes of interest has historically been a time-consuming process, beginning with generation of an outcrossed recombinant mapping population of phenotypically mutant and WT mice, genotyping individual mice at genetic markers across the genome to create a linkage map, and finally targeted sequencing to identify the causative mutation within the critical region. The advent of massively parallel sequencing techniques has given rise to more rapid "mapping-bysequencing" methods in which genome-wide marker genotyping and DNA sequencing are combined into a single step applied to either individual or pooled groups of organisms (1). For ENUmutagenized mice, early experiments used massively parallel sequencing for mutation identification within a critical region defined by traditional or bulk segregation mapping using recombinant mapping populations produced by outcrossing the mutant to another inbred laboratory strain and backcrossing or intercrossing a second time (2-4). Later reports demonstrated mapping with the identified sequence variants themselves as markers, which eliminated...

Structurally disparate molecules reportedly engage and activate Toll-like receptor (TLR) 4 and other TLRs, yet the interactions that mediate binding and activation by dissimilar ligands remain unknown. We describe Neoseptins, chemically synthesized peptidomimetics that bear no structural similarity to the established TLR4 ligand, lipopolysaccharide (LPS), but productively engage the mouse TLR4 (mTLR4)/ myeloid differentiation factor 2 (MD-2) complex. Neoseptin-3 activates mTLR4/MD-2 independently of CD14 and triggers canonical myeloid differentiation primary response gene 88 (MyD88)-and Toll-interleukin 1 receptor (TIR) domain-containing adaptor inducing IFN-beta (TRIF)-dependent signaling. The crystal structure mTLR4/MD-2/Neoseptin-3 at 2.57-Å resolution reveals that Neoseptin-3 binds as an asymmetrical dimer within the hydrophobic pocket of MD-2, inducing an active receptor complex similar to that induced by lipid A. However, Neoseptin-3 and lipid A form dissimilar molecular contacts to achieve receptor activation; hence strong TLR4/MD-2 agonists need not mimic LPS.neoseptins | peptidomimetic compounds | innate immunity | proinflammatory response | crystal structure

TNF␣ is a powerful inflammatory stimulus, central both to the control of infection, and as an agent of inflammatory disease. The most potent inducers of TNF␣ secretion signal through the Toll-like receptors, and we describe here a chemically-induced mutation that impairs this response in macrophages. A missense mutation was revealed in the gene encoding the inactive rhomboid protease iRhom2, which was not complemented by a null allele of the same gene. Neither the missense nor the null allele affected TLR-induced secretion of IL-6. Moreover, unlike a mutation in TNF␣, the iRhom2 missense mutation did not cause enhanced susceptibility to colitis induced by dextran sodium sulfate. These results establish a specific role for iRhom2 in the secretion of TNF␣, and present a new target for the modulation of inflammation. (Blood. 2012; 119(24):5769-5771) IntroductionTLR activation triggers a signaling pathway that culminates in the activation of NF-B and the synthesis of proinflammatory cytokines such as TNF␣. TNF␣, which is synthesized as a membranebound precursor, is liberated from the cell surface by the TNF␣ converting enzyme (TACE, also known as ADAM17). 1,2 Mammalian TACE is also required for the cleavage of other membranebound ligands, including the EGFR ligand TGF␣, 3 whose counterpart in Drosophila is cleaved by the unrelated protease rhomboid-1. 4,5 The rhomboid protease family is also present in mammals, and includes members with no predicted catalytic function, known as iRhoms. 6 Until very recently, the physiologic function of these proteins was unknown.To reveal new regulators of TLR-induced TNF␣, we have stimulated peritoneal macrophages from the progeny of chemicallymutagenized mice. 7 This screen has revealed mutant alleles throughout the pathway, from TLRs and the proteins that control their expression, 8 to TNF␣ itself. 9 Here we describe a new mutation affecting TLR-induced TNF␣ secretion that did not affect secretion of IL-6. The causative mutation lay in the gene encoding iRhom2, a catalytically inactive member of the rhomboid protease family. Methods Mice and positional cloningRhbdf2 sinecure was generated on a C57BL/6J background by N-ethyl-N-nitrosourea mutagenesis as previously described. 10 The index sinecure mutant (C57BL/6J, male) was outcrossed to C57BL/10J females (The Jackson Laboratory) for mapping, and F1 daughters were backcrossed to their father. Mice were grouped into mutant and wild-type cohorts (20 and 15 mice, respectively) based on TNF␣ secretion in response to MALP-2. Individual mice were typed at 70 polymorphic markers across the genome, and genotype frequencies were used to calculate LOD scores at each position. Rhbdf2 amplicons from wild-type and sinecure genomic DNA were sequenced using an ABI 3730xl capillary sequencer. C57BL/6J mice used for mutagenesis were obtained from The Jackson Laboratory. All other mice were obtained from the TSRI breeding colony. Ticam1 Lps2 and Irak2 otiose mutants have been described previously. 11,12 Rhbdf2 tm1a(KOMP)Wtsi ES cells (MGI:4362881, ...

Successful cancer immunotherapy entails activation of innate immune receptors to promote dendritic cell (DC) maturation, antigen presentation, up-regulation of costimulatory molecules, and cytokine secretion, leading to activation of tumor antigen-specific cytotoxic T lymphocytes (CTLs). Here we screened a synthetic library of 100,000 compounds for innate immune activators using TNF production by THP-1 cells as a readout. We identified and optimized a potent human and mouse Toll-like receptor (TLR)1/TLR2 agonist, Diprovocim, which exhibited an EC of 110 pM in human THP-1 cells and 1.3 nM in primary mouse peritoneal macrophages. In mice, Diprovocim-adjuvanted ovalbumin immunization promoted antigen-specific humoral and CTL responses and synergized with anti-PD-L1 treatment to inhibit tumor growth, generating long-term antitumor memory, curing or prolonging survival of mice engrafted with the murine melanoma B16-OVA. Diprovocim induced greater frequencies of tumor-infiltrating leukocytes than alum, of which CD8 T cells were necessary for the antitumor effect of immunization plus anti-PD-L1 treatment.