Transfer RNA-derived small RNAs in the cancer transcriptome

The cellular lifetime includes stages such as differentiation, proliferation, division, senescence and apoptosis.These stages are driven by a strictly ordered process of transcription dynamics. Molecular disruption to RNA polymerase assembly, chromatin remodelling and transcription factor binding through to RNA editing, splicing, post-transcriptional regulation and ribosome scanning can result in significant costs arising from genome instability. Cancer development is one example of when such disruption takes place. RNA silencing is a term used to describe the effects of post-transcriptional gene silencing mediated by a diverse set of small RNA molecules. Small RNAs are crucial for regulating gene expression and microguarding genome integrity.RNA silencing studies predominantly focus on small RNAs such as microRNAs, short-interfering RNAs and piwi-interacting RNAs. We describe an emerging renewal of inter-est in a‘larger’small RNA, the transfer RNA (tRNA).Precisely generated tRNA-derived small RNAs, named tRNA halves (tiRNAs) and tRNA fragments (tRFs), have been reported to be abundant with dysregulation associated with cancer. Transfection of tiRNAs inhibits protein translation by displacing eukaryotic initiation factors from messenger RNA (mRNA) and inaugurating stress granule formation.Knockdown of an overexpressed tRF inhibits cancer cell proliferation. Recovery of lacking tRFs prevents cancer metastasis. The dual oncogenic and tumour-suppressive role is typical of functional small RNAs. We review recent reports on tiRNA and tRF discovery and biogenesis, identification and analysis from next-generation sequencing data and a mechanistic animal study to demonstrate their physiological role in cancer biology. We propose tRNA-derived small RNA-mediated RNA silencing is an innate defence mechanism to prevent oncogenic translation. We expect that cancer cells are percipient to their ablated control of transcription and attempt to prevent loss of genome control through RNA silencing

Partial lung resection of supernumerary tracheal bronchus combined with pulmonary artery sling in an adult: report of a case

An adult case of pulmonary resection for repeated infections in a supernumerary tracheal bronchus combined with a pulmonary artery sling is reported. A 33-year-old woman with a pulmonary artery sling was referred for recurrent lung infections. Chest computed tomography showed the left pulmonary artery arising from the right pulmonary artery and coursing posterior to the trachea. The lung parenchyma connected to the tracheal bronchus showed dense opacity and traction bronchiectasis. Partial pulmonary resection was performed with an ultrasonically activated scalpel after the tracheal bronchus was auto-sutured. The patient\u27s postoperative course was uneventful, and she is now in good condition

Enhanced resistance to bacterial and fungal pathogens by overexpression of a human cathelicidin antimicrobial peptide (hCAP18/LL-37) in Chinese cabbage

The human cathelicidin antimicrobial protein hCAP18, which includes the C-terminal peptide LL-37, is a multifunctional protein. As a possible approach to enhancing the resistance to plant disease, a DNA fragment coding for hCAP18/LL-37 was fused at the C-terminal end of the leader sequence of endopolygalacturonase-inhibiting protein under the control of the cauliflower mosaic virus 35S promoter region. The construct was then introduced into Brassica rapa. LL-37 expression was confirmed in transgenic plants by reverse transcription-polymerase chain reaction and western blot analysis. Transgenic plants exhibited varying levels of resistance to bacterial and fungal pathogens. The average size of disease lesions in the transgenic plants was reduced to less than half of that in wild-type plants. Our results suggest that the antimicrobial LL-37 peptide is involved in wide-spectrum resistance to bacterial and fungal pathogen infection

Beryllium increases the CD14^dimCD16+ subset in the lung of chronic beryllium disease

CD14dimCD16+ and CD14brightCD16+ cells, which compose a minor population of monocytes in human peripheral blood mononuclear cells (PBMC), have been implicated in several inflammatory diseases. The aim of this study was to investigate whether this phenotype was present as a subset of lung infiltrative alveolar macrophages (AMs) in the granulomatous lung disease, chronic beryllium disease (CBD). The monocytes subsets was determined from PBMC cells and bronchoalveolar lavage (BAL) cells from CBD, beryllium sensitized Non-smoker (BeS-NS) and healthy subjects (HS) using flow cytometry. The impact of smoking on the AMs cell phenotype was determined by using BAL cells from BeS smokers (BeS-S). In comparison with the other monocyte subpopulations, CD14dimCD16+ cells were at decreased frequency in PBMCs of both BeS-NS and CBD and showed higher HLA-DR expression, compared to HS. The AMs from CBD and BeS-NS demonstrated a CD14dimCD16+phenotype, while CD14brightCD16+ cells were found at increased frequency in AMs of BeS, compared to HS. Fresh AMs from BeS-NS and CBD demonstrated significantly greater CD16, CD40, CD86 and HLA-DR than HS and BeS-S. The expression of CD16 on AMs from both CBD and BeS-NS was downregulated significantly after 10μM BeSO4 stimulation. The phagocytic activity of AMs decreased after 10μM BeSO4 treatment in both BeS-NS and CBD, although was altered or reduced in HS and BeS-S. These results suggest that Be increases the CD14dimCD16+ subsets in the lung of CBD subjects. We speculate that Be-stimulates the compartmentalization of a more mature CD16+ macrophage phenotype and that in turn these macrophages are a source of Th1 cytokines and chemokines that perpetuate the Be immune response in CBD. The protective effect of cigarette smoking in BeS-S may be due to the low expression of co-stimulatory markers on AMs from smokers as well as the decreased phagocytic function

Small molecule receptor tyrosine kinase inhibitor of platelet-derived growth factor signaling (SU9518) modifies radiation response in fibroblasts and endothelial cells

BACKGROUND: Several small receptor tyrosine kinase inhibitors (RTKI) have entered clinical cancer trials alone and in combination with radiotherapy or chemotherapy. The inhibitory spectrum of these compounds is often not restricted to a single target. For example Imatinib/Gleevec (primarily a bcr/abl kinase inhibitor) or SU11248 (mainly a VEGFR inhibitor) are also potent inhibitors of PDGFR and other kinases. We showed previously that PDGF signaling inhibition attenuates radiation-induced lung fibrosis in a mouse model. Here we investigate effects of SU9518, a PDGFR inhibitor combined with ionizing radiation in human primary fibroblasts and endothelial cells in vitro, with a view on utilizing RTKI for antifibrotic therapy. METHODS: Protein levels of PDGFR-α/-β and phosphorylated PDGFR in fibroblasts were analyzed using western and immunocytochemistry assays. Functional proliferation and clonogenic assays were performed (i) to assess PDGFR-mediated survival and proliferation in fibroblasts and endothelial cells after SU9518 (small molecule inhibitor of PDGF receptor tyrosine kinase); (ii) to test the potency und selectivity of the PDGF RTK inhibitor after stimulation with PDGF isoforms (-AB, -AA, -BB) and VEGF+bFGF. In order to simulate in vivo conditions and to understand the role of radiation-induced paracrine PDGF secretion, co-culture models consisting of fibroblasts and endothelial cells were employed. RESULTS: In fibroblasts, radiation markedly activated PDGF signaling as detected by enhanced PDGFR phosphorylation which was potently inhibited by SU9518. In fibroblast clonogenic assay, SU9518 reduced PDGF stimulated fibroblast survival by 57%. Likewise, SU9518 potently inhibited fibroblast and endothelial cell proliferation. In the co-culture model, radiation of endothelial cells and fibroblast cells substantially stimulated proliferation of non irradiated fibroblasts and vice versa. Importantly, the RTK inhibitor significantly inhibited this paracrine radiation-induced fibroblast and endothelial cell activation. CONCLUSION: Radiation-induced autocrine and paracrine PDGF signaling plays an important role in fibroblast and endothelial cell proliferation. SU9518, a PDGFR tyrosine kinase inhibitor, reduces radiation-induced fibroblast and endothelial cell activation. This may explain therapeutic anticancer effects of Imatinib/Gleevec, and at the same time it could open a way of attenuating radiation-induced fibrosis

Lipid Raft-Dependent FcεRI Ubiquitination Regulates Receptor Endocytosis through the Action of Ubiquitin Binding Adaptors

The best characterized role for ubiquitination of membrane receptors is to negatively regulate signaling by targeting receptors for lysosomal degradation. The high affinity receptor for IgE (FcepsilonRI) expressed on mast cells and basophils is rapidly ubiquitinated upon antigen stimulation. However, the nature and the role of this covalent modification are still largelly unknown. Here, we show that FcepsilonRI subunits are preferentially ubiquitinated at multiple sites upon stimulation, and provide evidence for a role of ubiquitin as an internalization signal: under conditions of impaired receptor ubiquitination a decrease of receptor entry is observed by FACS analysis and fluorescence microscopy. We also used biochemical approaches combined with fluorescence microscopy, to demonstrate that receptor endocytosis requires the integrity of specific membrane domains, namely lipid rafts. Additionally, by RNA interference we demonstrate the involvement of ubiquitin-binding endocytic adaptors in FcepsilonRI internalization and sorting. Notably, the triple depletion of Eps15, Eps15R and Epsin1 negatively affects the early steps of Ag-induced receptor endocytosis, whereas Hrs depletion retains ubiquitinated receptors into early endosomes and partially prevents their sorting into lysosomes for degradation. Our results are compatible with a scenario in which the accumulation of engaged receptor subunits into lipid rafts is required for receptor ubiquitination, a prerequisite for efficient receptor internalization, sorting and delivery to a lysosomal compartment

Allopurinol Reduces the Lethality Associated with Acute Renal Failure Induced by Crotalus durissus terrificus Snake Venom: Comparison with Probenecid

In Brazil, among registered snake bites, those by the genus Crotalus originate the highest mortality rate. The rattlesnake Crotalus durissus terrificus is the most frequently implicated in these accidents. The kidney is a particularly vulnerable organ to the venom of this rattlesnake. In fact, the most serious complication of Crotalus snake bite is the renal dysfunction, and among the fatal cases of Crotalus bites in Brazil 5% are patients treated with antivenom. The hyperuricemia has been observed in human accidents with snake venoms, but this parameter has not received any special attention as a relevant factor in the etiology of renal dysfunction caused by these venoms. This study examined the effects of treatments with low-cost and low-risk uricostatic (allopurinol) and uricosuric (probenecid) drugs on the envenomation by C. d. terrificus, showing that allopurinol and probenecid mitigated certain nephrotoxic effects, as well as the survival of envenomed mice was improved through the effects of allopurinol on reduction of oxidative stress and intracellular formation of uric acid. This new knowledge provides consistent evidences linking uric acid with the renal dysfunction induced by rattlesnake bites and that the allopurinol deserves to be clinically evaluated as an approach complementary to anti-snake venom serotherapy

Protein kinase C α and ε phosphorylation of troponin and myosin binding protein C reduce Ca2+ sensitivity in human myocardium

Previous studies indicated that the increase in protein kinase C (PKC)-mediated myofilament protein phosphorylation observed in failing myocardium might be detrimental for contractile function. This study was designed to reveal and compare the effects of PKCα- and PKCε-mediated phosphorylation on myofilament function in human myocardium. Isometric force was measured at different [Ca2+] in single permeabilized cardiomyocytes from failing human left ventricular tissue. Activated PKCα and PKCε equally reduced Ca2+ sensitivity in failing cardiomyocytes (ΔpCa50 = 0.08 ± 0.01). Both PKC isoforms increased phosphorylation of troponin I- (cTnI) and myosin binding protein C (cMyBP-C) in failing cardiomyocytes. Subsequent incubation of failing cardiomyocytes with the catalytic subunit of protein kinase A (PKA) resulted in a further reduction in Ca2+ sensitivity, indicating that the effects of both PKC isoforms were not caused by cross-phosphorylation of PKA sites. Both isozymes showed no effects on maximal force and only PKCα resulted in a modest significant reduction in passive force. Effects of PKCα were only minor in donor cardiomyocytes, presumably because of already saturated cTnI and cMyBP-C phosphorylation levels. Donor tissue could therefore be used as a tool to reveal the functional effects of troponin T (cTnT) phosphorylation by PKCα. Massive dephosphorylation of cTnT with alkaline phosphatase increased Ca2+ sensitivity. Subsequently, PKCα treatment of donor cardiomyocytes reduced Ca2+ sensitivity (ΔpCa50 = 0.08 ± 0.02) and solely increased phosphorylation of cTnT, but did not affect maximal and passive force. PKCα- and PKCε-mediated phosphorylation of cMyBP-C and cTnI as well as cTnT decrease myofilament Ca2+ sensitivity and may thereby reduce contractility and enhance relaxation of human myocardium

Rejuvenation of metallic glasses by non-affine thermal strain.

When a spatially uniform temperature change is imposed on a solid with more than one phase, or on a polycrystal of a single, non-cubic phase (showing anisotropic expansion-contraction), the resulting thermal strain is inhomogeneous (non-affine). Thermal cycling induces internal stresses, leading to structural and property changes that are usually deleterious. Glasses are the solids that form on cooling a liquid if crystallization is avoided--they might be considered the ultimate, uniform solids, without the microstructural features and defects associated with polycrystals. Here we explore the effects of cryogenic thermal cycling on glasses, specifically metallic glasses. We show that, contrary to the null effect expected from uniformity, thermal cycling induces rejuvenation, reaching less relaxed states of higher energy. We interpret these findings in the context that the dynamics in liquids become heterogeneous on cooling towards the glass transition, and that there may be consequent heterogeneities in the resulting glasses. For example, the vibrational dynamics of glassy silica at long wavelengths are those of an elastic continuum, but at wavelengths less than approximately three nanometres the vibrational dynamics are similar to those of a polycrystal with anisotropic grains. Thermal cycling of metallic glasses is easily applied, and gives improvements in compressive plasticity. The fact that such effects can be achieved is attributed to intrinsic non-uniformity of the glass structure, giving a non-uniform coefficient of thermal expansion. While metallic glasses may be particularly suitable for thermal cycling, the non-affine nature of strains in glasses in general deserves further study, whether they are induced by applied stresses or by temperature change.This research was supported by the World Premier International Research Center Initiative (WPI), MEXT, Japan, by NSF China and MOST 973 China, and by the Engineering and the Engineering and Physical Sciences Research Council, UK (Materials World Network project). Y.H.S. acknowledges support from a China Scholarship Council (CSC) scholarship.This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/nature1467

Three dimensional structure directs T-cell epitope dominance associated with allergy

<p>Abstract</p> <p>Background</p> <p>CD4+ T-cell epitope immunodominance is not adequately explained by peptide selectivity in class II major histocompatibility proteins, but it has been correlated with adjacent segments of conformational flexibility in several antigens.</p> <p>Methods</p> <p>The published T-cell responses to two venom allergens and two aeroallergens were used to construct profiles of epitope dominance, which were correlated with the distribution of conformational flexibility, as measured by crystallographic B factors, solvent-accessible surface, COREX residue stability, and sequence entropy.</p> <p>Results</p> <p>Epitopes associated with allergy tended to be excluded from and lie adjacent to flexible segments of the allergen.</p> <p>Conclusion</p> <p>During the initiation of allergy, the N- and/or C-terminal ends of proteolytic processing intermediates were preferentially loaded into antigen presenting proteins for the priming of CD4+ T cells.</p