Nucleic acid sensing by T cells initiates Th2 cell differentiationImanishi, Takayuki; Ishihara, Chitose; Badr, Mohamed El Sherif Gadelhaq; Hashimoto-Tane, Akiko; Kimura, Yayoi; Kawai, Taro; Takeuchi, Osamu; Ishii, Ken J.; Taniguchi, Shun'ichiro; Noda, Tetsuo; Hirano, Hisashi; Brombacher, Frank; Barber, Glen N.; Akira, Shizuo; Saito, Takashi
doi: 10.1038/ncomms4566pmid: 24717539
While T-cell responses are directly modulated by Toll-like receptor (TLR) ligands, the mechanism and physiological function of nucleic acids (NAs)-mediated T cell costimulation remains unclear. Here we show that unlike in innate cells, T-cell costimulation is induced even by non-CpG DNA and by self-DNA, which is released from dead cells and complexes with antimicrobial peptides or histones. Such NA complexes are internalized by T cells and induce costimulatory responses independently of known NA sensors, including TLRs, RIG-I-like receptors (RLRs), inflammasomes and STING-dependent cytosolic DNA sensors. Such NA-mediated costimulation crucially induces Th2 differentiation by suppressing T-bet expression, followed by the induction of GATA-3 and Th2 cytokines. These findings unveil the function of NA sensing by T cells to trigger and amplify allergic inflammation.
Site occupancy of interstitial deuterium atoms in face-centred cubic ironMachida, Akihiko; Saitoh, Hiroyuki; Sugimoto, Hidehiko; Hattori, Takanori; Sano-Furukawa, Asami; Endo, Naruki; Katayama, Yoshinori; Iizuka, Riko; Sato, Toyoto; Matsuo, Motoaki; Orimo, Shin-ichi; Aoki, Katsutoshi
doi: 10.1038/ncomms6063pmid: 25256789
Hydrogen composition and occupation state provide basic information for understanding various properties of the metal–hydrogen system, ranging from microscopic properties such as hydrogen diffusion to macroscopic properties such as phase stability. Here the deuterization process of face-centred cubic Fe to form solid-solution face-centred cubic FeDx is investigated using in situ neutron diffraction at high temperature and pressure. In a completely deuterized specimen at 988 K and 6.3 GPa, deuterium atoms occupy octahedral and tetrahedral interstitial sites with an occupancy of 0.532(9) and 0.056(5), respectively, giving a deuterium composition x of 0.64(1). During deuterization, the metal lattice expands approximately linearly with deuterium composition at a rate of 2.21 Å3 per deuterium atom. The minor occupation of the tetrahedral site is thermally driven by the intersite movement of deuterium atoms along the ‹111› direction in the face-centred cubic metal lattice.
RETRACTED ARTICLE: Senescence impairs direct conversion of human somatic cells to neuronsSun, Chong-kui; Zhou, Di; Zhang, Zhen; He, Liming; Zhang, Fan; Wang, Xiaowei; Yuan, Jie; Chen, Qianming; Wu, Ling-Gang; Yang, Qin
doi: 10.1038/ncomms5112pmid: 24934763
Recent reports have shown that fibroblasts can be converted to neurons by forced expression of transcription factors. However, the mechanisms underlying this conversion remain unclear. Here, we show that the efficiency of neuronal conversion of embryonic human fibroblasts aged in culture is lower than that in cells in early culture stages. Moreover, depletion of p16Ink4aand p19Arf involved in the activation of cellular senescence is sufficient to convert human fibroblast and epithelial cells into neurons. The induced neurons express neuron-specific proteins, generate action potentials and neurotransmitter receptor-mediated currents. Genome-wide transcriptional analysis shows that the induced neurons have a profile different from fibroblasts and similar to that of control neurons induced by established methods. We further noted that expression of p53 blocks the neuronal conversion, whereas expression of human telomerase reverse transcriptase (hTERT) induces it. Our results indicate that overcoming senescence is a crucial step for neuronal conversion of somatic cells.
RETRACTED ARTICLE: O-GlcNAc-mediated interaction between VER2 and TaGRP2 elicits TaVRN1 mRNA accumulation during vernalization in winter wheatXiao, Jun; Xu, Shujuan; Li, Chunhua; Xu, Yunyuan; Xing, Lijing; Niu, Yuda; Huan, Qing; Tang, Yimiao; Zhao, Changping; Wagner, Doris; Gao, Caixia; Chong, Kang
doi: 10.1038/ncomms5572pmid: 25091017
Vernalization, sensing of prolonged cold, is important for seasonal flowering in eudicots and monocots. While vernalization silences a repressor (FLC, MADS-box transcription factor) in eudicots, it induces an activator (TaVRN1, an AP1 clade MADS-box transcription factor) in monocots. The mechanism for TaVRN1 induction during vernalization is not well understood. Here we reveal a novel mechanism for controlling TaVRN1 mRNA accumulation in response to prolonged cold sensing in wheat. The carbohydrate-binding protein VER2, a jacalin lectin, promotes TaVRN1 upregulation by physically interacting with the RNA-binding protein TaGRP2. TaGRP2 binds to TaVRN1 pre-mRNA and inhibits TaVRN1 mRNA accumulation. The physical interaction between VER2 and TaGRP2 is controlled by TaGRP2 O-GlcNAc modification, which gradually increases during vernalization. The interaction between VER2 and O-GlcNAc-TaGRP2 reduces TaGRP2 protein accumulation in the nucleus and/or promotes TaGRP2 dissociation from TaVRN1, leading to TaVRN1 mRNA accumulation. Our data reveal a new mechanism for sensing prolonged cold in temperate cereals.
Dynamic SUMO modification regulates mitotic chromosome assembly and cell cycle progression in Caenorhabditis elegansPelisch, Federico; Sonneville, Remi; Pourkarimi, Ehsan; Agostinho, Ana; Blow, J. Julian; Gartner, Anton; Hay, Ronald T.
doi: 10.1038/ncomms6485pmid: 25475837
The small ubiquitin-like modifier (SUMO), initially characterized as a suppressor of a mutation in the gene encoding the centromeric protein MIF2, is involved in many aspects of cell cycle regulation. The dynamics of conjugation and deconjugation and the role of SUMO during the cell cycle remain unexplored. Here we used Caenorhabditis elegans to establish the contribution of SUMO to a timely and accurate cell division. Chromatin-associated SUMO conjugates increase during metaphase but decrease rapidly during anaphase. Accumulation of SUMO conjugates on the metaphase plate and proper chromosome alignment depend on the SUMO E2 conjugating enzyme UBC-9 and SUMO E3 ligase PIASGEI-17. Deconjugation is achieved by the SUMO protease ULP-4 and is crucial for correct progression through the cell cycle. Moreover, ULP-4 is necessary for Aurora BAIR-2 extraction from chromatin and relocation to the spindle mid-zone. Our results show that dynamic SUMO conjugation plays a role in cell cycle progression.
Antigen capture and archiving by lymphatic endothelial cells following vaccination or viral infectionTamburini, Beth A.; Burchill, Matthew A.; Kedl, Ross M.
doi: 10.1038/ncomms4989pmid: 24905362
Antigen derived from viral infections with influenza and vesicular stomatitis virus can persist after resolution of infection. Here we show that antigen can similarly persist for weeks following viral challenge and vaccination. Antigen is captured by lymphatic endothelial cells (LECs) under conditions that induce LEC proliferation. Consistent with published data showing that viral antigen persistence impacts the function of circulating memory T cells, we find that vaccine-elicited antigen persistence, found on LECs, positively influences the degree of protective immunity provided by circulating memory CD8+ T cells. The coupling of LEC proliferation and antigen capture identifies a mechanism by which the LECs store, or ‘archive’, antigens for extended periods of time after antigen challenge, thereby increasing IFNγ/IL-2 production and enhancing protection against infection. These findings therefore have the potential to have an impact on future vaccination strategies and our understanding of the role for persisting antigen in both vaccine and infectious settings.