Eukaryotic Initiation Factor (eIF) 4F Binding to Barley Yellow Dwarf Virus (BYDV) 3′-Untranslated Region Correlates with Translation Efficiency*

PubMed Central

Banerjee, Bidisha; Goss, Dixie J.

2014-01-01

Eukaryotic initiation factor (eIF) 4F binding to mRNA is the first committed step in cap-dependent protein synthesis. Barley yellow dwarf virus (BYDV) employs a cap-independent mechanism of translation initiation that is mediated by a structural BYDV translation element (BTE) located in the 3′-UTR of its mRNA. eIF4F bound the BTE and a translationally inactive mutant with high affinity, thus questioning the role of eIF4F in translation of BYDV. To examine the effects of eIF4F in BYDV translation initiation, BTE mutants with widely different in vitro translation efficiencies ranging from 5 to 164% compared with WT were studied. Using fluorescence anisotropy to obtain quantitative data, we show 1) the equilibrium binding affinity (complex stability) correlated well with translation efficiency, whereas the “on” rate of binding did not; 2) other unidentified proteins or small molecules in wheat germ extract prevented eIF4F binding to mutant BTE but not WT BTE; 3) BTE mutant-eIF4F interactions were found to be both enthalpically and entropically favorable with an enthalpic contribution of 52–90% to ΔG° at 25 °C, suggesting that hydrogen bonding contributes to stability; and 4) in contrast to cap-dependent and tobacco etch virus internal ribosome entry site interaction with eIF4F, poly(A)-binding protein did not increase eIF4F binding. Further, the eIF4F bound to the 3′ BTE with higher affinity than for either m7G cap or tobacco etch virus internal ribosome entry site, suggesting that the 3′ BTE may play a role in sequestering host cell initiation factors and possibly regulating the switch from replication to translation. PMID:24379412

Eukaryotic Initiation Factor 4E Binding Protien Family of Protiens: Sentinels at a Translational Control Checkpoint in Lung Tumor Defense

PubMed Central

Kim, Yong Y; Von Weymarn, Linda; Larsson, Ola; Fan, Danhua; Underwood, Jon M; Hecht, Stephen S; Polunovsky, Vitaly A; Bitterman, Peter B

2009-01-01

The usurping of translational control by sustained activation of translation initiation factors is oncogenic. Here we show that the primary negative regulators of these oncogenic initiation factors - the 4E-BP protein family - operate as guardians of a translational control checkpoint in lung tumor defense. When challenged with the tobacco carcinogen NNK, 4ebp1−/−/4ebp2−/− mice showed increased sensitivity to tumorigenesis compared to their wild type counterparts. The 4E-BP deficient state per se creates pro-oncogenic, genome-wide skewing of the molecular landscape - with translational activation of genes governing angiogenesis, growth and proliferation; and translational activation of the precise cytochrome p450 enzyme isoform (CYP2A5) that bioactivates NNK into mutagenic metabolites. Our study provides in vivo proof for a translational control checkpoint in lung tumor defense. PMID:19843855

Electronic cigarette initiation among minority youth in the United States.

PubMed

Hammig, Bart; Daniel-Dobbs, Page; Blunt-Vinti, Heather

2017-05-01

Electronic cigarettes (e-cigarette) use among youth is a pressing public health issue, with prevalence of use surpassing that of tobacco cigarettes. While research concerning e-cigarettes has proliferated in recent years, there is a dearth of information regarding those whose first exposure to tobacco products was an e-cigarette. To examine factors associated with e-cigarette initiation among minority youth in the United States. Data on minority students in middle and high schools in the United States derived from the 2014 National Youth Tobacco Survey (NYTS) were sampled (weighted N = 27,294,454). We examined e-cigarette initiation among minority youth using logistic regression models to identify related factors. In 2014, 736,158 minority youth were e-cigarette initiators. Odds of e-cigarette initiation was highest among Hispanic youth [adjusted odds ratio (AOR) = 2.70; 95% confidence interval (CI) = 1.60-4.56]. Exposure to e-cigarette advertising (AOR = 1.64; 95% CI = 1.07-2.50), perceptions of little to no harm (AOR = 7.08; 95% CI = 4.03-12.46), and believing e-cigarettes were less addictive than tobacco (AOR = 2.15; 95% CI = 1.52-3.02) were associated with e-cigarette initiation. Odds of initiating e-cigarette use was highest among Hispanic youth. Among minority youth, e-cigarette initiation was associated with perceptions of harm and addiction potential, as well as exposure to e-cigarette advertising. Therefore, prevention efforts targeting minority youth who are at risk of becoming e-cigarette initiators may benefit by incorporating these factors into prevention campaigns.

Inhibition of ribosome recruitment induces stress granule formation independently of eukaryotic initiation factor 2alpha phosphorylation.

PubMed

Mazroui, Rachid; Sukarieh, Rami; Bordeleau, Marie-Eve; Kaufman, Randal J; Northcote, Peter; Tanaka, Junichi; Gallouzi, Imed; Pelletier, Jerry

2006-10-01

Cytoplasmic aggregates known as stress granules (SGs) arise as a consequence of cellular stress and contain stalled translation preinitiation complexes. These foci are thought to serve as sites of mRNA storage or triage during the cell stress response. SG formation has been shown to require induction of eukaryotic initiation factor (eIF)2alpha phosphorylation. Herein, we investigate the potential role of other initiation factors in this process and demonstrate that interfering with eIF4A activity, an RNA helicase required for the ribosome recruitment phase of translation initiation, induces SG formation and that this event is not dependent on eIF2alpha phosphorylation. We also show that inhibition of eIF4A activity does not impair the ability of eIF2alpha to be phosphorylated under stress conditions. Furthermore, we observed SG assembly upon inhibition of cap-dependent translation after poliovirus infection. We propose that SG modeling can occur via both eIF2alpha phosphorylation-dependent and -independent pathways that target translation initiation.

Inhibition of Ribosome Recruitment Induces Stress Granule Formation Independently of Eukaryotic Initiation Factor 2α Phosphorylation

PubMed Central

Mazroui, Rachid; Sukarieh, Rami; Bordeleau, Marie-Eve; Kaufman, Randal J.; Northcote, Peter; Tanaka, Junichi; Gallouzi, Imed

2006-01-01

Cytoplasmic aggregates known as stress granules (SGs) arise as a consequence of cellular stress and contain stalled translation preinitiation complexes. These foci are thought to serve as sites of mRNA storage or triage during the cell stress response. SG formation has been shown to require induction of eukaryotic initiation factor (eIF)2α phosphorylation. Herein, we investigate the potential role of other initiation factors in this process and demonstrate that interfering with eIF4A activity, an RNA helicase required for the ribosome recruitment phase of translation initiation, induces SG formation and that this event is not dependent on eIF2α phosphorylation. We also show that inhibition of eIF4A activity does not impair the ability of eIF2α to be phosphorylated under stress conditions. Furthermore, we observed SG assembly upon inhibition of cap-dependent translation after poliovirus infection. We propose that SG modeling can occur via both eIF2α phosphorylation-dependent and -independent pathways that target translation initiation. PMID:16870703

Eukaryotic Translation Initiation Factor eIFiso4G Is Required to Regulate Violaxanthin De-epoxidase Expression in Arabidopsis*

PubMed Central

Chen, Zhong; Jolley, Blair; Caldwell, Christian; Gallie, Daniel R.

2014-01-01

The eukaryotic translation initiation factor (eIF) 4G is a scaffold protein that organizes the assembly of those initiation factors needed to recruit the 40 S ribosomal subunit to an mRNA. Plants, like many eukaryotes, express two eIF4G isoforms. eIFiso4G, one of the isoforms specific to plants, is unique among eukaryotic eIF4G proteins in that it is highly divergent and unusually small in size, raising the possibility of functional specialization. In this study, the role of eIFiso4G in plant growth was investigated using null mutants for the eIF4G isoforms in Arabidopsis. eIFiso4G loss of function mutants exhibited smaller cell, leaf, plant size, and biomass accumulation that correlated with its reduced photosynthetic activity, phenotypes not observed with the eIF4G loss of function mutant. Although no change in photorespiration or dark respiration was observed in the eIFiso4G loss of function mutant, a reduction in chlorophyll levels and an increase in the level of nonphotochemical quenching were observed. An increase in xanthophyll cycle activity and the generation of reactive oxygen species contributed to the qE and qI components of nonphotochemical quenching, respectively. An increase in the transcript and protein levels of violaxanthin de-epoxidase in the eIFiso4G loss of function mutant and an increase in its xanthophyll de-epoxidation state correlated with the higher qE associated with loss of eIFiso4G expression. These observations indicate that eIFiso4G expression is required to regulate violaxanthin de-epoxidase expression and to support photosynthetic activity. PMID:24706761

Eukaryotic Translation Initiation Factor 4E Is a Feed-Forward Translational Coactivator of Transforming Growth Factor β Early Protransforming Events in Breast Epithelial Cells

PubMed Central

Decarlo, Lindsey; Mestel, Celine; Barcellos-Hoff, Mary-Helen

2015-01-01

Eukaryotic translation initiation factor 4E (eIF4E) is overexpressed early in breast cancers in association with disease progression and reduced survival. Much remains to be understood regarding the role of eIF4E in human cancer. We determined, using immortalized human breast epithelial cells, that elevated expression of eIF4E translationally activates the transforming growth factor β (TGF-β) pathway, promoting cell invasion, a loss of cell polarity, increased cell survival, and other hallmarks of early neoplasia. Overexpression of eIF4E is shown to facilitate the selective translation of integrin β1 mRNA, which drives the translationally controlled assembly of a TGF-β receptor signaling complex containing α3β1 integrins, β-catenin, TGF-β receptor I, E-cadherin, and phosphorylated Smad2/3. This receptor complex acutely sensitizes nonmalignant breast epithelial cells to activation by typically substimulatory levels of activated TGF-β. TGF-β can promote cellular differentiation or invasion and transformation. As a translational coactivator of TGF-β, eIF4E confers selective mRNA translation, reprogramming nonmalignant cells to an invasive phenotype by reducing the set point for stimulation by activated TGF-β. Overexpression of eIF4E may be a proinvasive facilitator of TGF-β activity. PMID:25986608

Enhance tumor radiosensitivity by intracellular delivery of eukaryotic translation initiation factor 4E binding proteins.

PubMed

Tian, Shuang; Li, Xiu-Li; Shi, Mei; Yao, Yuan-Qing; Li, Li-Wen; Xin, Xiao-Yan

2011-02-01

PTEN (phosphatase and tensin homologue deleted on chromosome ten)/PI3K (phosphatidylinositol 3-kinase)/Akt/mTOR (mammalian target of rapamycin) signaling pathway, which is commonly dysregulated in a broad array of human malignancies, controls the assembly of eukaryotic translation initiation factor 4F (eIF4F) complex through regulation of eIF4E binding proteins (4E-BPs) phosphorylation. And accumulated data over the past two decades implicated eIF4F complex as one of the promising targets for anticancer therapy. It has been confirmed that the translation initiation of mRNA coding for hypoxia-inducible factor-1α (HIF-1α) and survivin, which had been considered as the two major determinants of tumor radiosensitivity, are both controlled by eIF4F complex. Also, eIF4F complex controls the expression of VEGF and bFGF, the two well-known pro-angiogenic factors involved in developing radioresistance. Therefore eIF4F complex plays a pivotal role in regulation of radiosensitivity. In this article, we postulate that cell-permeable, phosphorylation-defective 4E-BP fusion proteins, which could be prepared by substituting the mTOR recognition motif located in N-terminal of 4E-BPs with protein transduction domain from HIV-1 TAT, HSV-1 VP22 or PTD4, could not only inhibit tumor growth but also enhance tumor response to radiation therapy through disruption of eIF4F complex assembly. In our opinion, the recombinant fusion proteins are superior to mTOR inhibitors for they do not cause immunosuppression, do not lead to Akt activation, and could be easily prepared by prokaryotic expression. If the hypothesis was proved to be practical, the cell-permeable, phosphorylation-defective 4E-BP fusion proteins would be widely used in clinical settings to improve tumor response to radiotherapy in the near future. Copyright © 2010 Elsevier Ltd. All rights reserved.

Toward the mechanism of eIF4F-mediated ribosomal attachment to mammalian capped mRNAs.

PubMed

Kumar, Parimal; Hellen, Christopher U T; Pestova, Tatyana V

2016-07-01

Ribosomal attachment to mammalian capped mRNAs is achieved through the cap-eukaryotic initiation factor 4E (eIF4E)-eIF4G-eIF3-40S chain of interactions, but the mechanism by which mRNA enters the mRNA-binding channel of the 40S subunit remains unknown. To investigate this process, we recapitulated initiation on capped mRNAs in vitro using a reconstituted translation system. Formation of initiation complexes at 5'-terminal AUGs was stimulated by the eIF4E-cap interaction and followed "the first AUG" rule, indicating that it did not occur by backward scanning. Initiation complexes formed even at the very 5' end of mRNA, implying that Met-tRNAi (Met) inspects mRNA from the first nucleotide and that initiation does not have a "blind spot." In assembled initiation complexes, the cap was no longer associated with eIF4E. Omission of eIF4A or disruption of eIF4E-eIF4G-eIF3 interactions converted eIF4E into a specific inhibitor of initiation on capped mRNAs. Taken together, these results are consistent with the model in which eIF4E-eIF4G-eIF3-40S interactions place eIF4E at the leading edge of the 40S subunit, and mRNA is threaded into the mRNA-binding channel such that Met-tRNAi (Met) can inspect it from the first nucleotide. Before entering, eIF4E likely dissociates from the cap to overcome steric hindrance. We also found that the m(7)G cap specifically interacts with eIF3l. © 2016 Kumar et al.; Published by Cold Spring Harbor Laboratory Press.

Therapeutic suppression of translation initiation factor eIF4E expression reduces tumor growth without toxicity

PubMed Central

Graff, Jeremy R.; Konicek, Bruce W.; Vincent, Thomas M.; Lynch, Rebecca L.; Monteith, David; Weir, Spring N.; Schwier, Phil; Capen, Andrew; Goode, Robin L.; Dowless, Michele S.; Chen, Yuefeng; Zhang, Hong; Sissons, Sean; Cox, Karen; McNulty, Ann M.; Parsons, Stephen H.; Wang, Tao; Sams, Lillian; Geeganage, Sandaruwan; Douglass, Larry E.; Neubauer, Blake Lee; Dean, Nicholas M.; Blanchard, Kerry; Shou, Jianyong; Stancato, Louis F.; Carter, Julia H.; Marcusson, Eric G.

2007-01-01

Expression of eukaryotic translation initiation factor 4E (eIF4E) is commonly elevated in human and experimental cancers, promoting angiogenesis and tumor growth. Elevated eIF4E levels selectively increase translation of growth factors important in malignancy (e.g., VEGF, cyclin D1) and is thereby an attractive anticancer therapeutic target. Yet to date, no eIF4E-specific therapy has been developed. Herein we report development of eIF4E-specific antisense oligonucleotides (ASOs) designed to have the necessary tissue stability and nuclease resistance required for systemic anticancer therapy. In mammalian cultured cells, these ASOs specifically targeted the eIF4E mRNA for destruction, repressing expression of eIF4E-regulated proteins (e.g., VEGF, cyclin D1, survivin, c-myc, Bcl-2), inducing apoptosis, and preventing endothelial cells from forming vessel-like structures. Most importantly, intravenous ASO administration selectively and significantly reduced eIF4E expression in human tumor xenografts, significantly suppressing tumor growth. Because these ASOs also target murine eIF4E, we assessed the impact of eIF4E reduction in normal tissues. Despite reducing eIF4E levels by 80% in mouse liver, eIF4E-specific ASO administration did not affect body weight, organ weight, or liver transaminase levels, thereby providing the first in vivo evidence that cancers may be more susceptible to eIF4E inhibition than normal tissues. These data have prompted eIF4E-specific ASO clinical trials for the treatment of human cancers. PMID:17786246

Characterisation of the biological response of Saccharomyces cerevisiae to the loss of an allele of the eukaryotic initiation factor 4A.

PubMed

Venturi, Veronica; Little, Richard; Bircham, Peter W; Rodigheri Brito, Juliana; Atkinson, Paul H; Maass, David R; Teesdale-Spittle, Paul H

2018-02-19

The translation initiation machinery is emerging as an important target for therapeutic intervention, with potential in the treatment of cancer, viral infections, and muscle wasting. Amongst the targets for pharmacological control of translation initiation is the eukaryotic initiation factor 4A (eIF4A), an RNA helicase that is essential for cap-dependent translation initiation. We set out to explore the system-wide impact of a reduction of functional eIF4A. To this end, we investigated the effect of deletion of TIF1, one of the duplicate genes that produce eIF4A in yeast, through synthetic genetic array interactions and system-wide changes in GFP-tagged protein abundances. We show that there is a biological response to deletion of the TIF1 gene that extends through the proteostasis network. Effects of the deletion are apparent in processes as distributed as chromatin remodelling, ribosome biogenesis, amino acid metabolism, and protein trafficking. The results from this study identify protein complexes and pathways that will make ideal targets for combination therapies with eIF4A inhibitors. Copyright © 2018 Elsevier Inc. All rights reserved.

Norovirus translation requires an interaction between the C Terminus of the genome-linked viral protein VPg and eukaryotic translation initiation factor 4G.

PubMed

Chung, Liliane; Bailey, Dalan; Leen, Eoin N; Emmott, Edward P; Chaudhry, Yasmin; Roberts, Lisa O; Curry, Stephen; Locker, Nicolas; Goodfellow, Ian G

2014-08-01

Viruses have evolved a variety of mechanisms to usurp the host cell translation machinery to enable translation of the viral genome in the presence of high levels of cellular mRNAs. Noroviruses, a major cause of gastroenteritis in man, have evolved a mechanism that relies on the interaction of translation initiation factors with the virus-encoded VPg protein covalently linked to the 5' end of the viral RNA. To further characterize this novel mechanism of translation initiation, we have used proteomics to identify the components of the norovirus translation initiation factor complex. This approach revealed that VPg binds directly to the eIF4F complex, with a high affinity interaction occurring between VPg and eIF4G. Mutational analyses indicated that the C-terminal region of VPg is important for the VPg-eIF4G interaction; viruses with mutations that alter or disrupt this interaction are debilitated or non-viable. Our results shed new light on the unusual mechanisms of protein-directed translation initiation. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Sapovirus Translation Requires an Interaction between VPg and the Cap Binding Protein eIF4E

PubMed Central

Hosmillo, Myra; Chaudhry, Yasmin; Kim, Deok-Song

2014-01-01

ABSTRACT Sapoviruses of the Caliciviridae family of small RNA viruses are emerging pathogens that cause gastroenteritis in humans and animals. Molecular studies on human sapovirus have been hampered due to the lack of a cell culture system. In contrast, porcine sapovirus (PSaV) can be grown in cell culture, making it a suitable model for understanding the infectious cycle of sapoviruses and the related enteric caliciviruses. Caliciviruses are known to use a novel mechanism of protein synthesis that relies on the interaction of cellular translation initiation factors with the virus genome-encoded viral protein genome (VPg) protein, which is covalently linked to the 5′ end of the viral genome. Using PSaV as a representative member of the Sapovirus genus, we characterized the role of the viral VPg protein in sapovirus translation. As observed for other caliciviruses, the PSaV genome was found to be covalently linked to VPg, and this linkage was required for the translation and the infectivity of viral RNA. The PSaV VPg protein was associated with the 4F subunit of the eukaryotic translation initiation factor (eIF4F) complex in infected cells and bound directly to the eIF4E protein. As has been previously demonstrated for feline calicivirus, a member of the Vesivirus genus, PSaV translation required eIF4E and the interaction between eIF4E and eIF4G. Overall, our study provides new insights into the novel mechanism of sapovirus translation, suggesting that sapovirus VPg can hijack the cellular translation initiation mechanism by recruiting the eIF4F complex through a direct eIF4E interaction. IMPORTANCE Sapoviruses, which are members of the Caliciviridae family, are one of the causative agents of viral gastroenteritis in humans. However, human sapovirus remains noncultivable in cell culture, hampering the ability to characterize the virus infectious cycle. Here, we show that the VPg protein from porcine sapovirus, the only cultivatable sapovirus, is essential for viral translation and functions via a direct interaction with the cellular translation initiation factor eIF4E. This work provides new insights into the novel protein-primed mechanism of calicivirus VPg-dependent translation initiation. PMID:25142584

Sapovirus translation requires an interaction between VPg and the cap binding protein eIF4E.

PubMed

Hosmillo, Myra; Chaudhry, Yasmin; Kim, Deok-Song; Goodfellow, Ian; Cho, Kyoung-Oh

2014-11-01

Sapoviruses of the Caliciviridae family of small RNA viruses are emerging pathogens that cause gastroenteritis in humans and animals. Molecular studies on human sapovirus have been hampered due to the lack of a cell culture system. In contrast, porcine sapovirus (PSaV) can be grown in cell culture, making it a suitable model for understanding the infectious cycle of sapoviruses and the related enteric caliciviruses. Caliciviruses are known to use a novel mechanism of protein synthesis that relies on the interaction of cellular translation initiation factors with the virus genome-encoded viral protein genome (VPg) protein, which is covalently linked to the 5' end of the viral genome. Using PSaV as a representative member of the Sapovirus genus, we characterized the role of the viral VPg protein in sapovirus translation. As observed for other caliciviruses, the PSaV genome was found to be covalently linked to VPg, and this linkage was required for the translation and the infectivity of viral RNA. The PSaV VPg protein was associated with the 4F subunit of the eukaryotic translation initiation factor (eIF4F) complex in infected cells and bound directly to the eIF4E protein. As has been previously demonstrated for feline calicivirus, a member of the Vesivirus genus, PSaV translation required eIF4E and the interaction between eIF4E and eIF4G. Overall, our study provides new insights into the novel mechanism of sapovirus translation, suggesting that sapovirus VPg can hijack the cellular translation initiation mechanism by recruiting the eIF4F complex through a direct eIF4E interaction. Sapoviruses, which are members of the Caliciviridae family, are one of the causative agents of viral gastroenteritis in humans. However, human sapovirus remains noncultivable in cell culture, hampering the ability to characterize the virus infectious cycle. Here, we show that the VPg protein from porcine sapovirus, the only cultivatable sapovirus, is essential for viral translation and functions via a direct interaction with the cellular translation initiation factor eIF4E. This work provides new insights into the novel protein-primed mechanism of calicivirus VPg-dependent translation initiation. Copyright © 2014 Hosmillo et al.

Human Cells Cultured under Physiological Oxygen Utilize Two Cap-binding Proteins to recruit Distinct mRNAs for Translation*

PubMed Central

Timpano, Sara; Uniacke, James

2016-01-01

Translation initiation is a focal point of translational control and requires the binding of eIF4E to the 5′ cap of mRNA. Under conditions of extreme oxygen depletion (hypoxia), human cells repress eIF4E and switch to an alternative cap-dependent translation mediated by a homolog of eIF4E, eIF4E2. This homolog forms a complex with the oxygen-regulated hypoxia-inducible factor 2α and can escape translation repression. This complex mediates cap-dependent translation under cell culture conditions of 1% oxygen (to mimic tumor microenvironments), whereas eIF4E mediates cap-dependent translation at 21% oxygen (ambient air). However, emerging evidence suggests that culturing cells in ambient air, or “normoxia,” is far from physiological or “normal.” In fact, oxygen in human tissues ranges from 1–11% or “physioxia.” Here we show that two distinct modes of cap-dependent translation initiation are active during physioxia and act on separate pools of mRNAs. The oxygen-dependent activities of eIF4E and eIF4E2 are elucidated by observing their polysome association and the status of mammalian target of rapamycin complex 1 (eIF4E-dependent) or hypoxia-inducible factor 2α expression (eIF4E2-dependent). We have identified oxygen conditions where eIF4E is the dominant cap-binding protein (21% normoxia or standard cell culture conditions), where eIF4E2 is the dominant cap-binding protein (1% hypoxia or ischemic diseases and cancerous tumors), and where both cap-binding proteins act simultaneously to initiate the translation of distinct mRNAs (1–11% physioxia or during development and stem cell differentiation). These data suggest that the physioxic proteome is generated by initiating translation of mRNAs via two distinct but complementary cap-binding proteins. PMID:27002144

Nutritional stress affects an atypical cap-binding protein in Leishmania.

PubMed

Zinoviev, Alexandra; Manor, Shachar; Shapira, Michal

2012-12-01

Many eukaryotes encode multiple isoforms of the cap-binding translation initiation factor (eIF4E). Leishmanias and other trypanosomatids encode four paralogs of this protein, but none can complement the eIF4E function in a yeast mutant. A low conservation is observed between the four paralogs, suggesting they assist these organisms survive a multitude of conditions encountered throughout the life cycle. Earlier attempts to decipher their function led to identification of LeishIF4E-4 as the canonical translation initiation factor. LeishIF4E-1 appears to function during thermal stress, via a mechanism not yet understood. LeishIF4E-3 hardly binds cap-4 and is, therefore, less likely to serve as a typical initiation factor. Although it interacts with an eIF4G homolog, LeishIF4G-4, the two polypeptides do not co-migrate on sucrose gradients. While LeishIF4E-3 enters large particles that increase in size during nutritional stress, LeishIF4G-4 is found only in the top fractions. Confocal microscopy localized LeishIF4E-3 (but not LeishIF4G-4) within nutritional stress-induced granules. Accordingly, interaction between the two proteins reduced upon starvation. We therefore propose that under normal conditions, LeishIF4G-4 sequesters LeishIF4E-3 in the cytoplasm. During a nutritional stress, LeishIF4E-3 is modified and released from LeishIF4G-4 to enter stress granules, where inactive mRNAs are stored. Binding of LeishIF4G-4 to LeishIF4E-3 requires a short peptide within the LeishIF4G-4 N-terminus, which bears no similarity to the consensus 4E-binding peptide, YXXXXLΦ. Mutational analysis combined with structure prediction indicates that this interaction is based on an obligatory, conserved α helix in LeishIF4G-4. These features further highlight the uniqueness of LeishIF4E-3 and how it interacts with its binding partners.

The eIF4E-binding proteins are modifiers of cytoplasmic eIF4E relocalization during the heat shock response.

PubMed

Sukarieh, R; Sonenberg, N; Pelletier, J

2009-05-01

Stress granules (SGs) arise as a consequence of cellular stress, contain stalled translation preinitiation complexes, and are associated with cell survival during environmental insults. SGs are dynamic entities with proteins relocating into and out of them during stress. Among the repertoire of proteins present in SGs is eukaryotic initiation factor 4E (eIF4E), a translation factor required for cap-dependent translation and that regulates a rate-limiting step for protein synthesis. Herein, we demonstrate that localization of eIF4E to SGs is dependent on the presence of a family of repressor proteins, eIF4E-binding proteins (4E-BPs). Our results demonstrate that 4E-BPs regulate the SG localization of eIF4E.

Oxidative stress increases eukaryotic initiation factor 4E phosphorylation in vascular cells.

PubMed Central

Duncan, Roger F; Peterson, Hazel; Hagedorn, Curt H; Sevanian, Alex

2003-01-01

Dysregulated cell growth can be caused by increased activity of protein synthesis eukaryotic initiation factor (eIF) 4E. Dysregulated cell growth is also characteristic of atherosclerosis. It is postulated that exposure of vascular cells, such as endothelial cells, smooth muscle cells and monocytes/macrophages, to oxidants, such as oxidized low-density lipoprotein (oxLDL), leads to the elaboration of growth factors and cytokines, which in turn results in smooth muscle cell hyperproliferation. To investigate whether activation of eIF4E might play a role in this hyperproliferative response, vascular cells were treated with oxLDL, oxidized lipid components of oxLDL and several model oxidants, including H(2)O(2) and dimethyl naphthoquinone. Exposure to each of these compounds led to a dose- and time-dependent increase in eIF4E phosphorylation in all three types of vascular cells, correlated with a modest increase in overall translation rate. No changes in eIF4EBP, eIF2 or eIF4B modification state were observed. Increased eIF4E phosphorylation was paralleled by increased presence of eIF4E in high-molecular-mass protein complexes characteristic of its most active form. Anti-oxidants at concentrations typically employed to block oxidant-induced cell signalling likewise promoted eIF4E phosphorylation. The results of this study indicate that increased eIF4E activity may contribute to the pathophysiological events in early atherogenesis by increasing the expression of translationally inefficient mRNAs encoding growth-promoting proteins. PMID:12215171

Fed levels of amino acids are required for the somatotropin-induced increase in muscle protein synthesis.

PubMed

Wilson, Fiona A; Suryawan, Agus; Orellana, Renán A; Nguyen, Hanh V; Jeyapalan, Asumthia S; Gazzaneo, Maria C; Davis, Teresa A

2008-10-01

Chronic somatotropin (pST) treatment in pigs increases muscle protein synthesis and circulating insulin, a known promoter of protein synthesis. Previously, we showed that the pST-mediated rise in insulin could not account for the pST-induced increase in muscle protein synthesis when amino acids were maintained at fasting levels. This study aimed to determine whether the pST-induced increase in insulin promotes skeletal muscle protein synthesis when amino acids are provided at fed levels and whether the response is associated with enhanced translation initiation factor activation. Growing pigs were treated with pST (0 or 180 microg x kg(-1) x day(-1)) for 7 days, and then pancreatic-glucose-amino acid clamps were performed. Amino acids were raised to fed levels in the presence of either fasted or fed insulin concentrations; glucose was maintained at fasting throughout. Muscle protein synthesis was increased by pST treatment and by amino acids (with or without insulin) (P<0.001). In pST-treated pigs, fed, but not fasting, amino acid concentrations further increased muscle protein synthesis rates irrespective of insulin level (P<0.02). Fed amino acids, with or without raised insulin concentrations, increased the phosphorylation of S6 kinase (S6K1) and eukaryotic initiation factor (eIF) 4E-binding protein 1 (4EBP1), decreased inactive 4EBP1.eIF4E complex association, and increased active eIF4E.eIF4G complex formation (P<0.02). pST treatment did not alter translation initiation factor activation. We conclude that the pST-induced stimulation of muscle protein synthesis requires fed amino acid levels, but not fed insulin levels. However, under the current conditions, the response to amino acids is not mediated by the activation of translation initiation factors that regulate mRNA binding to the ribosomal complex.

Importin 8 mediates m7G cap-sensitive nuclear import of the eukaryotic translation initiation factor eIF4E

PubMed Central

Volpon, Laurent; Culjkovic-Kraljacic, Biljana; Osborne, Michael J.; Ramteke, Anup; Sun, Qingxiang; Niesman, Ashley; Chook, Yuh Min; Borden, Katherine L. B.

2016-01-01

Regulation of nuclear-cytoplasmic trafficking of oncoproteins is critical for growth homeostasis. Dysregulated trafficking contributes to malignancy, whereas understanding the process can reveal unique therapeutic opportunities. Here, we focus on eukaryotic translation initiation factor 4E (eIF4E), a prooncogenic protein highly elevated in many cancers, including acute myeloid leukemia (AML). Typically, eIF4E is localized to both the nucleus and cytoplasm, where it acts in export and translation of specific methyl 7-guanosine (m7G)–capped mRNAs, respectively. Nuclear accumulation of eIF4E in patients who have AML is correlated with increased eIF4E-dependent export of transcripts encoding oncoproteins. The subcellular localization of eIF4E closely correlates with patients’ responses. During clinical responses to the m7G-cap competitor ribavirin, eIF4E is mainly cytoplasmic. At relapse, eIF4E reaccumulates in the nucleus, leading to elevated eIF4E-dependent mRNA export. We have identified importin 8 as a factor that directly imports eIF4E into the nucleus. We found that importin 8 is highly elevated in untreated patients with AML, leading to eIF4E nuclear accumulation. Importin 8 only imports cap-free eIF4E. Cap-dependent changes to the structure of eIF4E underpin this selectivity. Indeed, m7G cap analogs or ribavirin prevents nuclear entry of eIF4E, which mirrors the trafficking phenotypes observed in patients with AML. Our studies also suggest that nuclear entry is important for the prooncogenic activity of eIF4E, at least in this context. These findings position nuclear trafficking of eIF4E as a critical step in its regulation and position the importin 8–eIF4E complex as a novel therapeutic target. PMID:27114554

The eIF4E-binding proteins are modifiers of cytoplasmic eIF4E relocalization during the heat shock response

PubMed Central

Sukarieh, R.; Sonenberg, N.; Pelletier, J.

2009-01-01

Stress granules (SGs) arise as a consequence of cellular stress, contain stalled translation preinitiation complexes, and are associated with cell survival during environmental insults. SGs are dynamic entities with proteins relocating into and out of them during stress. Among the repertoire of proteins present in SGs is eukaryotic initiation factor 4E (eIF4E), a translation factor required for cap-dependent translation and that regulates a rate-limiting step for protein synthesis. Herein, we demonstrate that localization of eIF4E to SGs is dependent on the presence of a family of repressor proteins, eIF4E-binding proteins (4E-BPs). Our results demonstrate that 4E-BPs regulate the SG localization of eIF4E. PMID:19244480

Depletion of elongation initiation factor 4E binding proteins by CRISPR/Cas9 enhances the antiviral response in porcine cells.

PubMed

Ramírez-Carvajal, Lisbeth; Singh, Neetu; de los Santos, Teresa; Rodríguez, Luis L; Long, Charles R

2016-01-01

Type I interferons (IFNs) are key mediators of the innate antiviral response in mammalian cells. Elongation initiation factor 4E binding proteins (4E-BPs) are translational controllers of interferon regulatory factor 7 (IRF-7), the "master regulator" of IFN transcription. Previous studies have suggested that mouse cells depleted of 4E-BPs are more sensitive to IFNβ treatment and had lower viral loads as compared to wild type (WT) cells. However, such approach has not been tested as an antiviral strategy in livestock species. In this study, we tested the antiviral activity of porcine cells depleted of 4E-BP1 by a Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated protein-9 nuclease (Cas9) genome engineering system. We found that 4E-BP1 knockout (KO) porcine cells had increased expression of IFNα and β, IFN stimulated genes, and significant reduction in vesicular stomatitis virus titer as compare to WT cells. No phenotypical changes associated with CRISPR/Cas9 manipulation were observed in 4E-BP1 KO cells. This work highlights the use of the CRISPR/Cas9 system to enhance the antiviral response in porcine cells. Copyright © 2015 Elsevier B.V. All rights reserved.

Hippuristanol - A potent steroid inhibitor of eukaryotic initiation factor 4A

PubMed Central

Cencic, Regina; Pelletier, Jerry

2016-01-01

ABSTRACT Protein synthesis and its regulatory signaling pathways play essential roles in the initiation and maintenance of the cancer phenotype. Insight obtained over the last 3 decades on the mechanisms regulating translation in normal and transformed cells have revealed that perturbed control in cancer cells may offer an Achilles' heel for the development of novel anti-neoplastic agents. Several small molecule inhibitors have been identified and characterized that target translation initiation – more specifically, the rate-limiting step where ribosomes are recruited to mRNA templates. Among these, hippuristanol, a polyhydroxysteroid from the gorgonian Isis hippuris has been found to inhibit translation initiation by blocking the activity of eukaryotic initiation factor (eIF) 4A, an essential RNA helicase involved in this process. Herein, we highlight the biological properties of this compound, its potential development as an anti-cancer agent, and its use to validate eIF4A as an anti-neoplastic target. PMID:27335721

Fed levels of amino acids are required for the somatotropin-induced increase in muscle protein synthesis

PubMed Central

Wilson, Fiona A.; Suryawan, Agus; Orellana, Renán A.; Nguyen, Hanh V.; Jeyapalan, Asumthia S.; Gazzaneo, Maria C.; Davis, Teresa A.

2008-01-01

Chronic somatotropin (pST) treatment in pigs increases muscle protein synthesis and circulating insulin, a known promoter of protein synthesis. Previously, we showed that the pST-mediated rise in insulin could not account for the pST-induced increase in muscle protein synthesis when amino acids were maintained at fasting levels. This study aimed to determine whether the pST-induced increase in insulin promotes skeletal muscle protein synthesis when amino acids are provided at fed levels and whether the response is associated with enhanced translation initiation factor activation. Growing pigs were treated with pST (0 or 180 μg·kg−1·day−1) for 7 days, and then pancreatic-glucose-amino acid clamps were performed. Amino acids were raised to fed levels in the presence of either fasted or fed insulin concentrations; glucose was maintained at fasting throughout. Muscle protein synthesis was increased by pST treatment and by amino acids (with or without insulin) (P < 0.001). In pST-treated pigs, fed, but not fasting, amino acid concentrations further increased muscle protein synthesis rates irrespective of insulin level (P < 0.02). Fed amino acids, with or without raised insulin concentrations, increased the phosphorylation of S6 kinase (S6K1) and eukaryotic initiation factor (eIF) 4E-binding protein 1 (4EBP1), decreased inactive 4EBP1·eIF4E complex association, and increased active eIF4E·eIF4G complex formation (P < 0.02). pST treatment did not alter translation initiation factor activation. We conclude that the pST-induced stimulation of muscle protein synthesis requires fed amino acid levels, but not fed insulin levels. However, under the current conditions, the response to amino acids is not mediated by the activation of translation initiation factors that regulate mRNA binding to the ribosomal complex. PMID:18682537

The eIF4F and eIFiso4F Complexes of Plants: An Evolutionary Perspective

PubMed Central

Patrick, Ryan M.; Browning, Karen S.

2012-01-01

Translation initiation in eukaryotes requires a number of initiation factors to recruit the assembled ribosome to mRNA. The eIF4F complex plays a key role in initiation and is a common target point for regulation of protein synthesis. Most work on the translation machinery of plants to date has focused on flowering plants, which have both the eIF4F complex (eIF4E and eIF4G) as well as the plant-specific eIFiso4F complex (eIFiso4E and eIFiso4G). The increasing availability of plant genome sequence data has made it possible to trace the evolutionary history of these two complexes in plants, leading to several interesting discoveries. eIFiso4G is conserved throughout plants, while eIFiso4E only appears with the evolution of flowering plants. The eIF4G N-terminus, which has been difficult to annotate, appears to be well conserved throughout the plant lineage and contains two motifs of unknown function. Comparison of eIFiso4G and eIF4G sequence data suggests conserved features unique to eIFiso4G and eIF4G proteins. These findings have answered some questions about the evolutionary history of the two eIF4F complexes of plants, while raising new ones. PMID:22611336

Targeting the eIF4F translation initiation complex: a critical nexus for cancer development.

PubMed

Pelletier, Jerry; Graff, Jeremy; Ruggero, Davide; Sonenberg, Nahum

2015-01-15

Elevated protein synthesis is an important feature of many cancer cells and often arises as a consequence of increased signaling flux channeled to eukaryotic initiation factor 4F (eIF4F), the key regulator of the mRNA-ribosome recruitment phase of translation initiation. In many cellular and preclinical models of cancer, eIF4F deregulation results in changes in translational efficiency of specific mRNA classes. Importantly, many of these mRNAs code for proteins that potently regulate critical cellular processes, such as cell growth and proliferation, enhanced cell survival and cell migration that ultimately impinge on several hallmarks of cancer, including increased angiogenesis, deregulated growth control, enhanced cellular survival, epithelial-to-mesenchymal transition, invasion, and metastasis. By being positioned as the molecular nexus downstream of key oncogenic signaling pathways (e.g., Ras, PI3K/AKT/TOR, and MYC), eIF4F serves as a direct link between important steps in cancer development and translation initiation. Identification of mRNAs particularly responsive to elevated eIF4F activity that typifies tumorigenesis underscores the critical role of eIF4F in cancer and raises the exciting possibility of developing new-in-class small molecules targeting translation initiation as antineoplastic agents. ©2014 American Association for Cancer Research.

The Nematode Eukaryotic Translation Initiation Factor 4E/G Complex Works with a trans-Spliced Leader Stem-Loop To Enable Efficient Translation of Trimethylguanosine-Capped RNAs ▿ †

PubMed Central

Wallace, Adam; Filbin, Megan E.; Veo, Bethany; McFarland, Craig; Stepinski, Janusz; Jankowska-Anyszka, Marzena; Darzynkiewicz, Edward; Davis, Richard E.

2010-01-01

Eukaryotic mRNA translation begins with recruitment of the 40S ribosome complex to the mRNA 5′ end through the eIF4F initiation complex binding to the 5′ m7G-mRNA cap. Spliced leader (SL) RNA trans splicing adds a trimethylguanosine (TMG) cap and a sequence, the SL, to the 5′ end of mRNAs. Efficient translation of TMG-capped mRNAs in nematodes requires the SL sequence. Here we define a core set of nucleotides and a stem-loop within the 22-nucleotide nematode SL that stimulate translation of mRNAs with a TMG cap. The structure and core nucleotides are conserved in other nematode SLs and correspond to regions of SL1 required for early Caenorhabditis elegans development. These SL elements do not facilitate translation of m7G-capped RNAs in nematodes or TMG-capped mRNAs in mammalian or plant translation systems. Similar stem-loop structures in phylogenetically diverse SLs are predicted. We show that the nematode eukaryotic translation initiation factor 4E/G (eIF4E/G) complex enables efficient translation of the TMG-SL RNAs in diverse in vitro translation systems. TMG-capped mRNA translation is determined by eIF4E/G interaction with the cap and the SL RNA, although the SL does not increase the affinity of eIF4E/G for capped RNA. These results suggest that the mRNA 5′ untranslated region (UTR) can play a positive and novel role in translation initiation through interaction with the eIF4E/G complex in nematodes and raise the issue of whether eIF4E/G-RNA interactions play a role in the translation of other eukaryotic mRNAs. PMID:20154140

The nematode eukaryotic translation initiation factor 4E/G complex works with a trans-spliced leader stem-loop to enable efficient translation of trimethylguanosine-capped RNAs.

PubMed

Wallace, Adam; Filbin, Megan E; Veo, Bethany; McFarland, Craig; Stepinski, Janusz; Jankowska-Anyszka, Marzena; Darzynkiewicz, Edward; Davis, Richard E

2010-04-01

Eukaryotic mRNA translation begins with recruitment of the 40S ribosome complex to the mRNA 5' end through the eIF4F initiation complex binding to the 5' m(7)G-mRNA cap. Spliced leader (SL) RNA trans splicing adds a trimethylguanosine (TMG) cap and a sequence, the SL, to the 5' end of mRNAs. Efficient translation of TMG-capped mRNAs in nematodes requires the SL sequence. Here we define a core set of nucleotides and a stem-loop within the 22-nucleotide nematode SL that stimulate translation of mRNAs with a TMG cap. The structure and core nucleotides are conserved in other nematode SLs and correspond to regions of SL1 required for early Caenorhabditis elegans development. These SL elements do not facilitate translation of m(7)G-capped RNAs in nematodes or TMG-capped mRNAs in mammalian or plant translation systems. Similar stem-loop structures in phylogenetically diverse SLs are predicted. We show that the nematode eukaryotic translation initiation factor 4E/G (eIF4E/G) complex enables efficient translation of the TMG-SL RNAs in diverse in vitro translation systems. TMG-capped mRNA translation is determined by eIF4E/G interaction with the cap and the SL RNA, although the SL does not increase the affinity of eIF4E/G for capped RNA. These results suggest that the mRNA 5' untranslated region (UTR) can play a positive and novel role in translation initiation through interaction with the eIF4E/G complex in nematodes and raise the issue of whether eIF4E/G-RNA interactions play a role in the translation of other eukaryotic mRNAs.

Visualization of the Interaction between the Precursors of VPg, the Viral Protein Linked to the Genome of Turnip Mosaic Virus, and the Translation Eukaryotic Initiation Factor iso 4E In Planta▿

PubMed Central

Beauchemin, Chantal; Boutet, Nathalie; Laliberté, Jean-François

2007-01-01

The RNA genome of Turnip mosaic virus is covalently linked at its 5′ end to a viral protein known as VPg. This protein binds to the translation eukaryotic initiation factor iso 4E [eIF(iso)4E]. This interaction has been shown to be important for virus infection, although its exact biological function(s) has not been elucidated. In this study, we investigated the subcellular site of the VPg-eIF(iso)4E interaction using bimolecular fluorescence complementation (BiFC). As a first step, eIF(iso)4E, 6K-VPg-Pro, and VPg-Pro were expressed as full-length green fluorescent protein (GFP) fusions in Nicotiana benthamiana, and their subcellular localizations were visualized by confocal microscopy. eIF(iso)4E was predominantly associated with the endoplasmic reticulum (ER), and VPg-Pro was observed in the nucleus and possibly the nucleolus, while 6K-VPg-Pro-GFP induced the formation of cytoplasmic vesicles budding from the ER. In BiFC experiments, reconstituted green fluorescence was observed throughout the nucleus, with a preferential accumulation in subnuclear structures when the GFP split fragments were fused to VPg-Pro and eIF(iso)4E. On the other hand, the interaction of 6K-VPg-Pro with eIF(iso)4E was observed in cytoplasmic vesicles embedded in the ER. These data suggest that the association of VPg with the translation factor might be needed for two different functions, depending of the VPg precursor involved in the interaction. VPg-Pro interaction with eIF(iso)4E may be involved in perturbing normal cellular functions, while 6K-VPg-Pro interaction with the translation factor may be needed for viral RNA translation and/or replication. PMID:17079311

Eukaryotic Initiation Factor eIFiso4G1 and eIFiso4G2 Are Isoforms Exhibiting Distinct Functional Differences in Supporting Translation in Arabidopsis*

PubMed Central

Gallie, Daniel R.

2016-01-01

The eukaryotic translation initiation factor (eIF) 4G is required during protein synthesis to promote the assembly of several factors involved in the recruitment of a 40S ribosomal subunit to an mRNA. Although many eukaryotes express two eIF4G isoforms that are highly similar, the eIF4G isoforms in plants, referred to as eIF4G and eIFiso4G, are highly divergent in size, sequence, and domain organization but both can interact with eIF4A, eIF4B, eIF4E isoforms, and the poly(A)-binding protein. Nevertheless, eIF4G and eIFiso4G from wheat exhibit preferences in the mRNAs they translate optimally. For example, mRNA containing the 5′-leader (called Ω) of tobacco mosaic virus preferentially uses eIF4G in wheat germ lysate. In this study, the eIF4G isoform specificity of Ω was used to examine functional differences of the eIF4G isoforms in Arabidopsis. As in wheat, Ω-mediated translation was reduced in an eif4g null mutant. Loss of the eIFiso4G1 isoform, which is similar in sequence to wheat eIFiso4G, did not substantially affect Ω-mediated translation. However, loss of the eIFiso4G2 isoform substantially reduced Ω-mediated translation. eIFiso4G2 is substantially divergent from eIFiso4G1 and is present only in the Brassicaceae, suggesting a recent evolution. eIFiso4G2 isoforms exhibit sequence-specific differences in regions representing partner protein and RNA binding sites. Loss of any eIF4G isoform also resulted in a substantial reduction in reporter transcript level. These results suggest that eIFiso4G2 appeared late in plant evolution and exhibits more functional similarity with eIF4G than with eIFiso4G1 during Ω-mediated translation. PMID:26578519

Selective regulation of YB-1 mRNA translation by the mTOR signaling pathway is not mediated by 4E-binding protein.

PubMed

Lyabin, D N; Ovchinnikov, L P

2016-03-02

The Y-box binding protein 1 (YB-1) is a key regulator of gene expression at the level of both translation and transcription. The mode of its action on cellular events depends on its subcellular distribution and the amount in the cell. So far, the regulatory mechanisms of YB-1 synthesis have not been adequately studied. Our previous finding was that selective inhibition of YB-1 mRNA translation was caused by suppression of activity of the mTOR signaling pathway. It was suggested that this event may be mediated by phosphorylation of the 4E-binding protein (4E-BP). Here, we report that 4E-BP alone can only slightly inhibit YB-1 synthesis both in the cell and in vitro, although it essentially decreases binding of the 4F-group translation initiation factors to mRNA. With inhibited mTOR kinase, the level of mRNA binding to the eIF4F-group factors was decreased, while that to 4E-BP1 was increased, as was observed for both mTOR kinase-sensitive mRNAs and those showing low sensitivity. This suggests that selective inhibition of translation of YB-1 mRNA, and probably some other mRNAs as well, by mTOR kinase inhibitors is not mediated by the action of the 4E-binding protein upon functions of the 4F-group translation initiation factors.

The unique Leishmania EIF4E4 N-terminus is a target for multiple phosphorylation events and participates in critical interactions required for translation initiation.

PubMed

de Melo Neto, Osvaldo P; da Costa Lima, Tamara D C; Xavier, Camila C; Nascimento, Larissa M; Romão, Tatiany P; Assis, Ludmila A; Pereira, Mariana M C; Reis, Christian R S; Papadopoulou, Barbara

2015-01-01

The eukaryotic initiation factor 4E (eIF4E) recognizes the mRNA cap structure and, together with eIF4G and eIF4A, form the eIF4F complex that regulates translation initiation in eukaryotes. In trypanosomatids, 2 eIF4E homologues (EIF4E3 and EIF4E4) have been shown to be part of eIF4F-like complexes with presumed roles in translation initiation. Both proteins possess unique N-terminal extensions, which can be targeted for phosphorylation. Here, we provide novel insights on the Leishmania infantum EIF4E4 function and regulation. We show that EIF4E4 is constitutively expressed throughout the parasite development but is preferentially phosphorylated in exponentially grown promastigote and amastigote life stages, hence correlating with high levels of translation. Phosphorylation targets multiple serine-proline or threonine-proline residues within the N-terminal extension of EIF4E4 but does not require binding to the EIF4E4's partner, EIF4G3, or to the cap structure. We also report that EIF4E4 interacts with PABP1 through 3 conserved boxes at the EIF4E4 N-terminus and that this interaction is a prerequisite for efficient EIF4E4 phosphorylation. EIF4E4 is essential for Leishmania growth and an EIF4E4 null mutant was only obtained in the presence of an ectopically provided wild type gene. Complementation for the loss of EIF4E4 with several EIF4E4 mutant proteins affecting either phosphorylation or binding to mRNA or to EIF4E4 protein partners revealed that, in contrast to other eukaryotes, only the EIF4E4-PABP1 interaction but neither the binding to EIF4G3 nor phosphorylation is essential for translation. These studies also demonstrated that the lack of both EIF4E4 phosphorylation and EIF4G3 binding leads to a non-functional protein. Altogether, these findings further highlight the unique features of the translation initiation process in trypanosomatid protozoa.

The unique Leishmania EIF4E4 N-terminus is a target for multiple phosphorylation events and participates in critical interactions required for translation initiation

PubMed Central

de Melo Neto, Osvaldo P; da Costa Lima, Tamara D C; Xavier, Camila C; Nascimento, Larissa M; Romão, Tatiany P; Assis, Ludmila A; Pereira, Mariana M C; Reis, Christian R S; Papadopoulou, Barbara

2015-01-01

The eukaryotic initiation factor 4E (eIF4E) recognizes the mRNA cap structure and, together with eIF4G and eIF4A, form the eIF4F complex that regulates translation initiation in eukaryotes. In trypanosomatids, 2 eIF4E homologues (EIF4E3 and EIF4E4) have been shown to be part of eIF4F-like complexes with presumed roles in translation initiation. Both proteins possess unique N-terminal extensions, which can be targeted for phosphorylation. Here, we provide novel insights on the Leishmania infantum EIF4E4 function and regulation. We show that EIF4E4 is constitutively expressed throughout the parasite development but is preferentially phosphorylated in exponentially grown promastigote and amastigote life stages, hence correlating with high levels of translation. Phosphorylation targets multiple serine-proline or threonine-proline residues within the N-terminal extension of EIF4E4 but does not require binding to the EIF4E4's partner, EIF4G3, or to the cap structure. We also report that EIF4E4 interacts with PABP1 through 3 conserved boxes at the EIF4E4 N-terminus and that this interaction is a prerequisite for efficient EIF4E4 phosphorylation. EIF4E4 is essential for Leishmania growth and an EIF4E4 null mutant was only obtained in the presence of an ectopically provided wild type gene. Complementation for the loss of EIF4E4 with several EIF4E4 mutant proteins affecting either phosphorylation or binding to mRNA or to EIF4E4 protein partners revealed that, in contrast to other eukaryotes, only the EIF4E4-PABP1 interaction but neither the binding to EIF4G3 nor phosphorylation is essential for translation. These studies also demonstrated that the lack of both EIF4E4 phosphorylation and EIF4G3 binding leads to a non-functional protein. Altogether, these findings further highlight the unique features of the translation initiation process in trypanosomatid protozoa. PMID:26338184

Serum-deprivation stimulates cap-binding by PARN at the expense of eIF4E, consistent with the observed decrease in mRNA stability

PubMed Central

Seal, Ruth; Temperley, Richard; Wilusz, Jeffrey; Lightowlers, Robert N.; Chrzanowska-Lightowlers, Zofia M. A.

2005-01-01

PARN, a poly(A)-specific ribonuclease, binds the 5′ cap-structure of mRNA and initiates deadenylation-dependent decay. Eukaryotic initiation factor 4E (eIF4E) also binds to the cap structure, an interaction that is critical for initiating cap-dependent translation. The stability of various mRNA transcripts in human cell lines is reduced under conditions of serum starvation as determined by both functional and chemical half-lives. Serum starvation also leads to enhanced cap association by PARN. In contrast, the 5′ cap occupancy by eIF4E decreases under serum-deprivation, as does the translation of reporter transcripts. Further, we show that PARN is a phosphoprotein and that this modification can be modulated by serum status. Taken together, these data are consistent with a natural competition existing at the 5′ cap structure between PARN and eIF4E that may be regulated by changes in post-translational modifications. These phosphorylation-induced changes in the interplay of PARN and eIF4E may determine whether the mRNA is translated or decayed. PMID:15653638

Activation by Insulin and Amino Acids of Signaling Components Leading to Translation Initiation in Skeletal Muscle of Neonatal Pigs Is Developmentally Regulated

PubMed Central

Suryawan, Agus; Orellana, Renan A.; Nguyen, Hanh V.; Jeyapalan, Asumthia S.; Fleming, Jillian R.; Davis, Teresa A.

2009-01-01

Insulin (INS) and amino acids (AA) act independently to stimulate protein synthesis in skeletal muscle of neonatal pigs and the responses decrease with development. The purpose of this study was to compare the separate effects of fed levels of INS and AA on the activation of signaling components leading to translation initiation and how these responses change with development. Overnight fasted 6-day-old (n=4/group) and 26-day-old (n=6/group) pigs were studied during: 1) euinsulinemic-euglycemic-euaminoacidemic conditions (controls), 2) euinsulinemic-euglycemic-hyperaminoacidemic clamps (AA), and 3) hyperinsulinemic-euglycemic-euaminoacidemic clamps (INS). INS, but not AA, increased the phosphorylation of protein kinase B (PKB) and tuberous sclerosis 2 (TSC2). Both INS and AA increased protein synthesis and the phosphorylation of mammalian target of rapamycin (mTOR), ribosomal protein S6 kinase-1, and eukaryotic initiation factor (eIF) 4E-binding protein 1 (4E-BP1) and these responses were higher in 6-day-old compared to 26-day-old pigs. Both INS and AA decreased the binding of 4E-BP1 to eIF4E and increased eIF4E binding to eIF4G; these effects were greater in 6-day-old than in 26-day-old pigs. Neither INS nor AA altered the composition of mTORC1 (raptor, mTOR, and GβL) or mTORC2 (rictor, mTOR, and GβL) complexes. Furthermore, neither INS, AA, nor age had any effect on the abundance of Rheb and the phosphorylation of AMP-activated kinase (AMPK) and eukaryotic elongation factor 2 (eEF2). Our results suggest that the activation by insulin and amino acids of signaling components leading to translation initiation is developmentally regulated and parallels the developmental decline in protein synthesis in skeletal muscle of neonatal pigs. PMID:17878222

Novel characteristics of the biological properties of the yeast Saccharomyces cerevisiae eukaryotic initiation factor 2A.

PubMed

Komar, Anton A; Gross, Stephane R; Barth-Baus, Diane; Strachan, Ryan; Hensold, Jack O; Goss Kinzy, Terri; Merrick, William C

2005-04-22

Eukaryotic initiation factor 2A (eIF2A) has been shown to direct binding of the initiator methionyl-tRNA (Met-tRNA(i)) to 40 S ribosomal subunits in a codon-dependent manner, in contrast to eIF2, which requires GTP but not the AUG codon to bind initiator tRNA to 40 S subunits. We show here that yeast eIF2A genetically interacts with initiation factor eIF4E, suggesting that both proteins function in the same pathway. The double eIF2A/eIF4E-ts mutant strain displays a severe slow growth phenotype, which correlated with the accumulation of 85% of the double mutant cells arrested at the G(2)/M border. These cells also exhibited a disorganized actin cytoskeleton and elevated actin levels, suggesting that eIF2A might be involved in controlling the expression of genes involved in morphogenic processes. Further insights into eIF2A function were gained from the studies of eIF2A distribution in ribosomal fractions obtained from either an eIF5BDelta (fun12Delta) strain or a eIF3b-ts (prt1-1) strain. It was found that the binding of eIF2A to 40 and 80 S ribosomes was not impaired in either strain. We also found that eIF2A functions as a suppressor of Ure2p internal ribosome entry site-mediated translation in yeast cells. The regulation of expression from the URE2 internal ribosome entry site appears to be through the levels of eIF2A protein, which has been found to be inherently unstable with a half-life of approximately 17 min. It was hypothesized that this instability allows for translational control through the level of eIF2A protein in yeast cells.

Structural modelling and phylogenetic analyses of PgeIF4A2 (Eukaryotic translation initiation factor) from Pennisetum glaucum reveal signature motifs with a role in stress tolerance and development

PubMed Central

Agarwal, Aakrati; Mudgil, Yashwanti; Pandey, Saurabh; Fartyal, Dhirendra; Reddy, Malireddy K

2016-01-01

Eukaryotic translation initiation factor 4A (eIF4A) is an indispensable component of the translation machinery and also play a role in developmental processes and stress alleviation in plants and animals. Different eIF4A isoforms are present in the cytosol of the cell, namely, eIF4A1, eIF4A2, and eIF4A3 and their expression is tightly regulated in cap-dependent translation. We revealed the structural model of PgeIF4A2 protein using the crystal structure of Homo sapiens eIF4A3 (PDB ID: 2J0S) as template by Modeller 9.12. The resultant PgeIF4A2 model structure was refined by PROCHECK, ProSA, Verify3D and RMSD that showed the model structure is reliable with 77 % amino acid sequence identity with template. Investigation revealed two conserved signatures for ATP-dependent RNA Helicase DEAD-box conserved site (VLDEADEML) and RNA helicase DEAD-box type, Q-motif in sheet-turn-helix and α-helical region respectively. All these conserved motifs are responsible for response during developmental stages and stress tolerance in plants. PMID:28358146

Structural modelling and phylogenetic analyses of PgeIF4A2 (Eukaryotic translation initiation factor) from Pennisetum glaucum reveal signature motifs with a role in stress tolerance and development.

PubMed

Agarwal, Aakrati; Mudgil, Yashwanti; Pandey, Saurabh; Fartyal, Dhirendra; Reddy, Malireddy K

2016-01-01

Eukaryotic translation initiation factor 4A (eIF4A) is an indispensable component of the translation machinery and also play a role in developmental processes and stress alleviation in plants and animals. Different eIF4A isoforms are present in the cytosol of the cell, namely, eIF4A1, eIF4A2, and eIF4A3 and their expression is tightly regulated in cap-dependent translation. We revealed the structural model of PgeIF4A2 protein using the crystal structure of Homo sapiens eIF4A3 (PDB ID: 2J0S) as template by Modeller 9.12. The resultant PgeIF4A2 model structure was refined by PROCHECK, ProSA, Verify3D and RMSD that showed the model structure is reliable with 77 % amino acid sequence identity with template. Investigation revealed two conserved signatures for ATP-dependent RNA Helicase DEAD-box conserved site (VLDEADEML) and RNA helicase DEAD-box type, Q-motif in sheet-turn-helix and α-helical region respectively. All these conserved motifs are responsible for response during developmental stages and stress tolerance in plants.

The small molecule '1-(4-biphenylylcarbonyl)-4-(5-bromo-2-methoxybenzyl) piperazine oxalate' and its derivatives regulate global protein synthesis by inactivating eukaryotic translation initiation factor 2-alpha.

PubMed

Hong, Mi-Na; Nam, Ky-Youb; Kim, Kyung Kon; Kim, So-Young; Kim, InKi

2016-05-01

By environmental stresses, cells can initiate a signaling pathway in which eukaryotic translation initiation factor 2-alpha (eIF2-α) is involved to regulate the response. Phosphorylation of eIF2-α results in the reduction of overall protein neogenesis, which allows cells to conserve resources and to reprogram energy usage for effective stress control. To investigate the role of eIF2-α in cell stress responses, we conducted a viability-based compound screen under endoplasmic reticulum (ER) stress condition, and identified 1-(4-biphenylylcarbonyl)-4-(5-bromo-2-methoxybenzyl) piperazine oxalate (AMC-01) and its derivatives as eIF2-α-inactivating chemical. Molecular characterization of this signaling pathway revealed that AMC-01 induced inactivation of eIF2-α by phosphorylating serine residue 51 in a dose- and time-dependent manner, while the negative control compounds did not affect eIF2-α phosphorylation. In contrast with ER stress induction by thapsigargin, phosphorylation of eIF2-α persisted for the duration of incubation with AMC-01. By pathway analysis, AMC-01 clearly induced the activation of protein kinase RNA-activated (PKR) kinase and nuclear factor-κB (NF-κB), whereas it did not modulate the activity of PERK or heme-regulated inhibitor (HRI). Finally, we could detect a lower protein translation rate in cells incubated with AMC-01, establishing AMC-01 as a potent chemical probe that can regulate eIF2-α activity. We suggest from these data that AMC-01 and its derivative compounds can be used as chemical probes in future studies of the role of eIF2-α in protein synthesis-related cell physiology.

Biological insights into the expression of translation initiation factors from recombinant CHOK1SV cell lines and their relationship to enhanced productivity.

PubMed

Mead, Emma J; Masterton, Rosalyn J; Feary, Marc; Obrezanova, Olga; Zhang, Lin; Young, Robert; Smales, C Mark

2015-12-15

Translation initiation is on the critical pathway for the production of monoclonal antibodies (mAbs) by mammalian cells. Formation of a closed loop structure comprised of mRNA, a number of eukaryotic initiation factors (eIFs) and ribosomal proteins has been proposed to aid re-initiation of translation and therefore increase global translational efficiency. We have determined mRNA and protein levels of the key components of the closed loop, eIFs (eIF3a, eIF3b, eIF3c, eIF3h, eIF3i and eIF4G1), poly(A)-binding protein (PABP) 1 and PABP-interacting protein 1 (PAIP1), across a panel of 30 recombinant mAb-producing GS-CHOK1SV cell lines with a broad range of growth characteristics and production levels of a model recombinant mAb. We have used a multi-level statistical approach to investigate the relationship between key performance indicators (cell growth and recombinant antibody productivity) and the intracellular amounts of target translation initiation factor proteins and the mRNAs encoding them. We show that high-producing cell lines maintain amounts of the translation initiation factors involved in the formation of the closed loop mRNA, maintaining these proteins at appropriate levels to deliver enhanced recombinant protein production. We then utilize knowledge of the amounts of these factors to build predictive models for and use cluster analysis to identify, high-producing cell lines. The present study therefore defines the translation initiation factor amounts that are associated with highly productive recombinant GS-CHOK1SV cell lines that may be targets for screening highly productive cell lines or to engineer new host cell lines with the potential for enhanced recombinant antibody productivity. © 2015 Authors; published by Portland Press Limited.

The Yeast Eukaryotic Translation Initiation Factor 2B Translation Initiation Complex Interacts with the Fatty Acid Synthesis Enzyme YBR159W and Endoplasmic Reticulum Membranes

PubMed Central

Browne, Christopher M.; Samir, Parimal; Fites, J. Scott; Villarreal, Seth A.

2013-01-01

Using affinity purifications coupled with mass spectrometry and yeast two-hybrid assays, we show the Saccharomyces cerevisiae translation initiation factor complex eukaryotic translation initiation factor 2B (eIF2B) and the very-long-chain fatty acid (VLCFA) synthesis keto-reductase enzyme YBR159W physically interact. The data show that the interaction is specifically between YBR159W and eIF2B and not between other members of the translation initiation or VLCFA pathways. A ybr159wΔ null strain has a slow-growth phenotype and a reduced translation rate but a normal GCN4 response to amino acid starvation. Although YBR159W localizes to the endoplasmic reticulum membrane, subcellular fractionation experiments show that a fraction of eIF2B cofractionates with lipid membranes in a YBR159W-independent manner. We show that a ybr159wΔ yeast strain and other strains with null mutations in the VLCFA pathway cause eIF2B to appear as numerous foci throughout the cytoplasm. PMID:23263984

Antitumor activity and mechanism of action of the cyclopenta[b]benzofuran, silvestrol.

PubMed

Cencic, Regina; Carrier, Marilyn; Galicia-Vázquez, Gabriela; Bordeleau, Marie-Eve; Sukarieh, Rami; Bourdeau, Annie; Brem, Brigitte; Teodoro, Jose G; Greger, Harald; Tremblay, Michel L; Porco, John A; Pelletier, Jerry

2009-01-01

Flavaglines are a family of natural products from the genus Aglaia that exhibit anti-cancer activity in vitro and in vivo and inhibit translation initiation. They have been shown to modulate the activity of eIF4A, the DEAD-box RNA helicase subunit of the eukaryotic initiation factor (eIF) 4F complex, a complex that stimulates ribosome recruitment during translation initiation. One flavagline, silvestrol, is capable of modulating chemosensitivity in a mechanism-based mouse model. Among a number of flavagline family members tested herein, we find that silvestrol is the more potent translation inhibitor among these. We find that silvestrol impairs the ribosome recruitment step of translation initiation by affecting the composition of the eukaryotic initiation factor (eIF) 4F complex. We show that silvestrol exhibits significant anticancer activity in human breast and prostate cancer xenograft models, and that this is associated with increased apoptosis, decreased proliferation, and inhibition of angiogenesis. We demonstrate that targeting translation by silvestrol results in preferential inhibition of weakly initiating mRNAs. Our results indicate that silvestrol is a potent anti-cancer compound in vivo that exerts its activity by affecting survival pathways as well as angiogenesis. We propose that silvestrol mediates its effects by preferentially inhibiting translation of malignancy-related mRNAs. Silvestrol appears to be well tolerated in animals.

Nuclear assortment of eIF4E coincides with shut-off of host protein synthesis upon poliovirus infection.

PubMed

Sukarieh, R; Sonenberg, N; Pelletier, J

2010-05-01

Eukaryotic initiation factor (eIF) 4E is a subunit of the cap-binding protein complex, eIF4F, which recognizes the cap structure of cellular mRNAs to facilitate translation initiation. eIF4E is assembled into the eIF4F complex via its interaction with eIF4G, an event that is under Akt/mTOR regulation. The eIF4E-eIF4G interaction is regulated by the eIF4E binding partners, eIF4E-binding proteins and eIF4E-transporter. Cleavage of eIF4G occurs upon poliovirus infection and is responsible for the shut-off of host-cell protein synthesis observed early in infection. Here, we document that relocalization of eIF4E to the nucleus occurs concomitantly with cleavage of eIF4G upon poliovirus infection. This event is not dependent upon virus replication, but is dependent on eIF4G cleavage. We postulate that eIF4E nuclear relocalization may contribute to the shut-off of host protein synthesis that is a hallmark of poliovirus infection by perturbing the circular status of actively translating mRNAs.

Activation by insulin and amino acids of signaling components leading to translation initiation in skeletal muscle of neonatal pigs is developmentally regulated.

PubMed

Suryawan, Agus; Orellana, Renan A; Nguyen, Hanh V; Jeyapalan, Asumthia S; Fleming, Jillian R; Davis, Teresa A

2007-12-01

Insulin and amino acids act independently to stimulate protein synthesis in skeletal muscle of neonatal pigs, and the responses decrease with development. The purpose of this study was to compare the separate effects of fed levels of INS and AA on the activation of signaling components leading to translation initiation and how these responses change with development. Overnight-fasted 6- (n = 4/group) and 26-day-old (n = 6/ group) pigs were studied during 1) euinsulinemic-euglycemiceuaminoacidemic conditions (controls), 2) euinsulinemic-euglycemichyperaminoacidemic clamps (AA), and 3) hyperinsulinemic-euglycemic-euaminoacidemic clamps (INS). INS, but not AA, increased the phosphorylation of protein kinase B (PKB) and tuberous sclerosis 2 (TSC2). Both INS and AA increased protein synthesis and the phosphorylation of mammalian target of rapamycin (mTOR), ribosomal protein S6 kinase-1, and eukaryotic initiation factor (eIF)4E-binding protein 1 (4E-BP1), and these responses were higher in 6-day-old compared with 26-day-old pigs. Both INS and AA decreased the binding of 4E-BP1 to eIF4E and increased eIF4E binding to eIF4G; these effects were greater in 6-day-old than in 26-day-old pigs. Neither INS nor AA altered the composition of mTORC1 (raptor, mTOR, and GbetaL) or mTORC2 (rictor, mTOR, and GbetaL) complexes. Furthermore, neither INS, AA, nor age had any effect on the abundance of Rheb and the phosphorylation of AMP-activated protein kinase and eukaryotic elongation factor 2. Our results suggest that the activation by insulin and amino acids of signaling components leading to translation initiation is developmentally regulated and parallels the developmental decline in protein synthesis in skeletal muscle of neonatal pigs.

Control of eIF4E cellular localization by eIF4E-binding proteins, 4E-BPs.

PubMed

Rong, Liwei; Livingstone, Mark; Sukarieh, Rami; Petroulakis, Emmanuel; Gingras, Anne-Claude; Crosby, Katherine; Smith, Bradley; Polakiewicz, Roberto D; Pelletier, Jerry; Ferraiuolo, Maria A; Sonenberg, Nahum

2008-07-01

Eukaryotic initiation factor (eIF) 4E, the mRNA 5'-cap-binding protein, mediates the association of eIF4F with the mRNA 5'-cap structure to stimulate cap-dependent translation initiation in the cytoplasm. The assembly of eIF4E into the eIF4F complex is negatively regulated through a family of repressor proteins, called the eIF4E-binding proteins (4E-BPs). eIF4E is also present in the nucleus, where it is thought to stimulate nuclear-cytoplasmic transport of certain mRNAs. eIF4E is transported to the nucleus via its interaction with 4E-T (4E-transporter), but it is unclear how it is retained in the nucleus. Here we show that a sizable fraction (approximately 30%) of 4E-BP1 is localized to the nucleus, where it binds eIF4E. In mouse embryo fibroblasts (MEFs) subjected to serum starvation and/or rapamycin treatment, nuclear 4E-BPs sequester eIF4E in the nucleus. A dramatic loss of nuclear 4E-BP1 occurs in c-Ha-Ras-expressing MEFs, which fail to show starvation-induced nuclear accumulation of eIF4E. Therefore, 4E-BP1 is a regulator of eIF4E cellular localization.

Control of eIF4E cellular localization by eIF4E-binding proteins, 4E-BPs

PubMed Central

Rong, Liwei; Livingstone, Mark; Sukarieh, Rami; Petroulakis, Emmanuel; Gingras, Anne-Claude; Crosby, Katherine; Smith, Bradley; Polakiewicz, Roberto D.; Pelletier, Jerry; Ferraiuolo, Maria A.; Sonenberg, Nahum

2008-01-01

Eukaryotic initiation factor (eIF) 4E, the mRNA 5′-cap-binding protein, mediates the association of eIF4F with the mRNA 5′-cap structure to stimulate cap-dependent translation initiation in the cytoplasm. The assembly of eIF4E into the eIF4F complex is negatively regulated through a family of repressor proteins, called the eIF4E-binding proteins (4E-BPs). eIF4E is also present in the nucleus, where it is thought to stimulate nuclear-cytoplasmic transport of certain mRNAs. eIF4E is transported to the nucleus via its interaction with 4E-T (4E-transporter), but it is unclear how it is retained in the nucleus. Here we show that a sizable fraction (∼30%) of 4E-BP1 is localized to the nucleus, where it binds eIF4E. In mouse embryo fibroblasts (MEFs) subjected to serum starvation and/or rapamycin treatment, nuclear 4E-BPs sequester eIF4E in the nucleus. A dramatic loss of nuclear 4E-BP1 occurs in c-Ha-Ras–expressing MEFs, which fail to show starvation-induced nuclear accumulation of eIF4E. Therefore, 4E-BP1 is a regulator of eIF4E cellular localization. PMID:18515545

Reliability Estimating Procedures for Electric and Thermochemical Propulsion Systems. Volume 2

DTIC Science & Technology

1977-02-01

final form. For some components, the parameters are calculated from design factors (e.g., design life) that must be input when requested. Each component...Components Components are regarded as statis- tically identical if they are drawn from the same production lot because the initial and sub- sequent...table yields b 0.0023 The - factors are obtained from Tables 2.2.4-1 through 2.2.4-5: Factor Value rE Space, flight 1 JANTXV quality 0.5 7A Small signal

A MAP4 kinase related to Ste20 is a nutrient-sensitive regulator of mTOR signalling

PubMed Central

Findlay, Greg M.; Yan, Lijun; Procter, Julia; Mieulet, Virginie; Lamb, Richard F.

2007-01-01

The mTOR (mammalian target of rapamycin) signalling pathway is a key regulator of cell growth and is controlled by growth factors and nutrients such as amino acids. Although signalling pathways from growth factor receptors to mTOR have been elucidated, the pathways mediating signalling by nutrients are poorly characterized. Through a screen for protein kinases active in the mTOR signalling pathway in Drosophila we have identified a Ste20 family member (MAP4K3) that is required for maximal S6K (S6 kinase)/4E-BP1 [eIF4E (eukaryotic initiation factor 4E)-binding protein 1] phosphorylation and regulates cell growth. Importantly, MAP4K3 activity is regulated by amino acids, but not the growth factor insulin and is not regulated by the mTORC1 inhibitor rapamycin. Our results therefore suggest a model whereby nutrients signal to mTORC1 via activation of MAP4K3. PMID:17253963

Canonical Initiation Factor Requirements of the Myc Family of Internal Ribosome Entry Segments▿ †

PubMed Central

Spriggs, Keith A.; Cobbold, Laura C.; Jopling, Catherine L.; Cooper, Rebecca E.; Wilson, Lindsay A.; Stoneley, Mark; Coldwell, Mark J.; Poncet, Didier; Shen, Ya-Ching; Morley, Simon J.; Bushell, Martin; Willis, Anne E.

2009-01-01

Initiation of protein synthesis in eukaryotes requires recruitment of the ribosome to the mRNA and its translocation to the start codon. There are at least two distinct mechanisms by which this process can be achieved; the ribosome can be recruited either to the cap structure at the 5′ end of the message or to an internal ribosome entry segment (IRES), a complex RNA structural element located in the 5′ untranslated region (5′-UTR) of the mRNA. However, it is not well understood how cellular IRESs function to recruit the ribosome or how the 40S ribosomal subunits translocate from the initial recruitment site on the mRNA to the AUG initiation codon. We have investigated the canonical factors that are required by the IRESs found in the 5′-UTRs of c-, L-, and N-myc, using specific inhibitors and a tissue culture-based assay system, and have shown that they differ considerably in their requirements. The L-myc IRES requires the eIF4F complex and the association of PABP and eIF3 with eIF4G for activity. The minimum requirements of the N- and c-myc IRESs are the C-terminal domain of eIF4G to which eIF4A is bound and eIF3, although interestingly this protein does not appear to be recruited to the IRES RNA via eIF4G. Finally, our data show that all three IRESs require a ternary complex, although in contrast to c- and L-myc IRESs, the N-myc IRES has a lesser requirement for a ternary complex. PMID:19124605

Sleep deprivation impairs memory by attenuating mTORC1-dependent protein synthesis.

PubMed

Tudor, Jennifer C; Davis, Emily J; Peixoto, Lucia; Wimmer, Mathieu E; van Tilborg, Erik; Park, Alan J; Poplawski, Shane G; Chung, Caroline W; Havekes, Robbert; Huang, Jiayan; Gatti, Evelina; Pierre, Philippe; Abel, Ted

2016-04-26

Sleep deprivation is a public health epidemic that causes wide-ranging deleterious consequences, including impaired memory and cognition. Protein synthesis in hippocampal neurons promotes memory and cognition. The kinase complex mammalian target of rapamycin complex 1 (mTORC1) stimulates protein synthesis by phosphorylating and inhibiting the eukaryotic translation initiation factor 4E-binding protein 2 (4EBP2). We investigated the involvement of the mTORC1-4EBP2 axis in the molecular mechanisms mediating the cognitive deficits caused by sleep deprivation in mice. Using an in vivo protein translation assay, we found that loss of sleep impaired protein synthesis in the hippocampus. Five hours of sleep loss attenuated both mTORC1-mediated phosphorylation of 4EBP2 and the interaction between eukaryotic initiation factor 4E (eIF4E) and eIF4G in the hippocampi of sleep-deprived mice. Increasing the abundance of 4EBP2 in hippocampal excitatory neurons before sleep deprivation increased the abundance of phosphorylated 4EBP2, restored the amount of eIF4E-eIF4G interaction and hippocampal protein synthesis to that seen in mice that were not sleep-deprived, and prevented the hippocampus-dependent memory deficits associated with sleep loss. These findings collectively demonstrate that 4EBP2-regulated protein synthesis is a critical mediator of the memory deficits caused by sleep deprivation. Copyright © 2016, American Association for the Advancement of Science.

Eukaryotic translational initiation factor 4AII reduces the replication of infectious bursal disease virus by inhibiting VP1 polymerase activity.

PubMed

Gao, Li; Li, Kai; Zhong, Li; Zhang, Lizhou; Qi, Xiaole; Wang, Yongqiang; Gao, Yulong; Wang, Xiaomei

2017-03-01

Infectious bursal disease (IBD) is an acute, highly contagious, and immunosuppressive avian disease caused by IBD virus (IBDV). Although an interaction between eukaryotic translational initiation factor 4AII (eIF4AII) of the host and viral protein 1 (VP1), the RNA-dependent RNA polymerase (RdRp) of IBDV, has been established, the underlying effects of this interaction on IBDV and the molecular mechanism remain unclear. We here report that interaction of the host eIF4AII with VP1 inhibits the RNA polymerase activity of IBDV to reduce its replication in host cells. We found that ectopically expressed eIF4AII markedly inhibited IBDV growth in DF1 cells, and knockdown of eIF4AII by small interfering RNA significantly enhanced viral replication in CEF cells. Furthermore, IBDV infection led to an increase in host eIF4AII expression, suggesting a feedback mechanism between the host and virus infection both in vitro and in vivo, which further confirmed the involvement of the host eIF4AII in the IBDV life cycle. Thus, via the interaction with VP1, eIF4AII plays a critical role in the IBDV life cycle, by inhibiting viral RNA polymerase activity, leading to a reduction of IBDV replication in cells. Copyright © 2016 Elsevier B.V. All rights reserved.

Plant Translation Factors and Virus Resistance

PubMed Central

Sanfaçon, Hélène

2015-01-01

Plant viruses recruit cellular translation factors not only to translate their viral RNAs but also to regulate their replication and potentiate their local and systemic movement. Because of the virus dependence on cellular translation factors, it is perhaps not surprising that many natural plant recessive resistance genes have been mapped to mutations of translation initiation factors eIF4E and eIF4G or their isoforms, eIFiso4E and eIFiso4G. The partial functional redundancy of these isoforms allows specific mutation or knock-down of one isoform to provide virus resistance without hindering the general health of the plant. New possible targets for antiviral strategies have also been identified following the characterization of other plant translation factors (eIF4A-like helicases, eIF3, eEF1A and eEF1B) that specifically interact with viral RNAs and proteins and regulate various aspects of the infection cycle. Emerging evidence that translation repression operates as an alternative antiviral RNA silencing mechanism is also discussed. Understanding the mechanisms that control the development of natural viral resistance and the emergence of virulent isolates in response to these plant defense responses will provide the basis for the selection of new sources of resistance and for the intelligent design of engineered resistance that is broad-spectrum and durable. PMID:26114476

Studying the Role of Eukaryotic Translation Initiation Factor 4E (eIF4E) Phosphorylation by MNK1/2 Kinases in Prostate Cancer Development and Progression

DTIC Science & Technology

2012-06-01

preclinical mouse model. J Clin Invest 118: 3051–3064. 49. Le Bacquer O, et al. (2007) Elevated sensitivity to diet-induced obesity and insulin resistance in...Elevated sensitivity to diet-induced obesity and insulin resistance in mice lacking 4E-BP1 and 4E-BP2. J Clin Invest 117:387–396. 7. Frederickson RM...that knock-in mice expressing a nonphosphorylatable form of eIF4E are resistant to tumorigenesis in a prostate cancer model. By using a genome-wide

Conformational changes induced in the eukaryotic translation initiation factor eIF4E by a clinically relevant inhibitor, ribavirin triphosphate

PubMed Central

Volpon, Laurent; Osborne, Michael J.; Zahreddine, Hiba; Romeo, Andrea A.; Borden, Katherine L.B.

2013-01-01

The eukaryotic translation initiation factor eIF4E is highly elevated in human cancers including acute myeloid leukemia (AML). A potential anticancer agent, ribavirin, targets eIF4E activity in AML patients corresponding to clinical responses. To date, ribavirin is the only direct inhibitor of eIF4E to reach clinical trials. We showed that ribavirin acts as a competitive inhibitor of the methyl 7-guanosine (m7G) cap, the natural ligand of eIF4E. Here we examine the conformational changes occurring in human eIF4E upon binding the active metabolite of ribavirin, ribavirin triphosphate (RTP). Our NMR data revealed an unexpected concentration dependence on RTP affinity for eIF4E. We observed NMR spectra characteristic of tight binding at low micromolar concentrations (2-5μM eIF4E) but much weaker affinity at more typical NMR concentrations (50-200μM). Comparison of chemical shift perturbation and line broadening suggest that the two eIF4E-RTP complexes differ in the precise positioning of RTP within the cap binding pocket, with the high affinity complex showing more extensive changes to the central β-sheet and dorsal surface of eIF4E, similar to m7G cap. The differences between high and low affinity complexes arise due to concentration dependent aggregation of eIF4E and RTP. Given the intracellular concentrations of eIF4E and RTP and the differential binding toward the W56A eIF4E mutant the high affinity complex is the most physiologically relevant. In summary, these findings demonstrate that RTP binds in the cap-binding site but also suggests new features of this pocket that should be considered in both drug design efforts and reveal new insights into ligand eIF4E recognition. PMID:23583375

Translation Initiation Factor AteIF(iso)4E Is Involved in Selective mRNA Translation in Arabidopsis Thaliana Seedlings

PubMed Central

Martínez-Silva, Ana Valeria; Aguirre-Martínez, César; Flores-Tinoco, Carlos E.; Alejandri-Ramírez, Naholi D.; Dinkova, Tzvetanka D.

2012-01-01

One of the most regulated steps of translation initiation is the recruitment of mRNA by the translation machinery. In eukaryotes, this step is mediated by the 5′end cap-binding factor eIF4E bound to the bridge protein eIF4G and forming the eIF4F complex. In plants, different isoforms of eIF4E and eIF4G form the antigenically distinct eIF4F and eIF(iso)4F complexes proposed to mediate selective translation. Using a microarray analysis of polyribosome- and non-polyribosome-purified mRNAs from 15 day-old Arabidopsis thaliana wild type [WT] and eIF(iso)4E knockout mutant [(iso)4E-1] seedlings we found 79 transcripts shifted from polyribosomes toward non-polyribosomes, and 47 mRNAs with the opposite behavior in the knockout mutant. The translationally decreased mRNAs were overrepresented in root-preferentially expressed genes and proteins from the endomembrane system, including several transporters such as the phosphate transporter PHOSPHATE1 (PHO1), Sucrose transporter 3 (SUC3), ABC transporter-like with ATPase activity (MRP11) and five electron transporters, as well as signal transduction-, protein modification- and transcription-related proteins. Under normal growth conditions, eIF(iso)4E expression under the constitutive promoter 35 S enhanced the polyribosomal recruitment of PHO1 supporting its translational preference for eIF(iso)4E. Furthermore, under phosphate deficiency, the PHO1 protein increased in the eIF(iso)4E overexpressing plants and decreased in the knockout mutant as compared to wild type. In addition, the knockout mutant had larger root, whereas the 35 S directed expression of eIF(iso)4E caused shorter root under normal growth conditions, but not under phosphate deficiency. These results indicate that selective translation mediated by eIF(iso)4E is relevant for Arabidopsis root development under normal growth conditions. PMID:22363683

Transgenic Brassica rapa plants over-expressing eIF(iso)4E variants show broad-spectrum Turnip mosaic virus (TuMV) resistance.

PubMed

Kim, Jinhee; Kang, Won-Hee; Hwang, Jeena; Yang, Hee-Bum; Dosun, Kim; Oh, Chang-Sik; Kang, Byoung-Cheorl

2014-08-01

The protein-protein interaction between VPg (viral protein genome-linked) of potyviruses and eIF4E (eukaryotic initiation factor 4E) or eIF(iso)4E of their host plants is a critical step in determining viral virulence. In this study, we evaluated the approach of engineering broad-spectrum resistance in Chinese cabbage (Brassica rapa) to Turnip mosaic virus (TuMV), which is one of the most important potyviruses, by a systematic knowledge-based approach to interrupt the interaction between TuMV VPg and B. rapa eIF(iso)4E. The seven amino acids in the cap-binding pocket of eIF(iso)4E were selected on the basis of other previous results and comparison of protein models of cap-binding pockets, and mutated. Yeast two-hybrid assay and co-immunoprecipitation analysis demonstrated that W95L, K150L and W95L/K150E amino acid mutations of B. rapa eIF(iso)4E interrupted its interaction with TuMV VPg. All eIF(iso)4E mutants were able to complement an eIF4E-knockout yeast strain, indicating that the mutated eIF(iso)4E proteins retained their function as a translational initiation factor. To determine whether these mutations could confer resistance, eIF(iso)4E W95L, W95L/K150E and eIF(iso)4E wild-type were over-expressed in a susceptible Chinese cabbage cultivar. Evaluation of the TuMV resistance of T1 and T2 transformants demonstrated that the over-expression of the eIF(iso)4E mutant forms can confer resistance to multiple TuMV strains. These data demonstrate the utility of knowledge-based approaches for the engineering of broad-spectrum resistance in Chinese cabbage. © 2014 BSPP AND JOHN WILEY & SONS LTD.

Antitumor Activity and Mechanism of Action of the Cyclopenta[b]benzofuran, Silvestrol

PubMed Central

Cencic, Regina; Carrier, Marilyn; Galicia-Vázquez, Gabriela; Bordeleau, Marie-Eve; Sukarieh, Rami; Bourdeau, Annie; Brem, Brigitte; Teodoro, Jose G.; Greger, Harald; Tremblay, Michel L.; Porco, John A.; Pelletier, Jerry

2009-01-01

Background Flavaglines are a family of natural products from the genus Aglaia that exhibit anti-cancer activity in vitro and in vivo and inhibit translation initiation. They have been shown to modulate the activity of eIF4A, the DEAD-box RNA helicase subunit of the eukaryotic initiation factor (eIF) 4F complex, a complex that stimulates ribosome recruitment during translation initiation. One flavagline, silvestrol, is capable of modulating chemosensitivity in a mechanism-based mouse model. Methodology/Principal Findings Among a number of flavagline family members tested herein, we find that silvestrol is the more potent translation inhibitor among these. We find that silvestrol impairs the ribosome recruitment step of translation initiation by affecting the composition of the eukaryotic initiation factor (eIF) 4F complex. We show that silvestrol exhibits significant anticancer activity in human breast and prostate cancer xenograft models, and that this is associated with increased apoptosis, decreased proliferation, and inhibition of angiogenesis. We demonstrate that targeting translation by silvestrol results in preferential inhibition of weakly initiating mRNAs. Conclusions/Significance Our results indicate that silvestrol is a potent anti-cancer compound in vivo that exerts its activity by affecting survival pathways as well as angiogenesis. We propose that silvestrol mediates its effects by preferentially inhibiting translation of malignancy-related mRNAs. Silvestrol appears to be well tolerated in animals. PMID:19401772

Structural analysis of the DAP5 MIF4G domain and its interaction with eIF4A

PubMed Central

Virgili, Geneviève; Frank, Filipp; Feoktistova, Kateryna; Sawicki, Maxime; Sonenberg, Nahum; Fraser, Christopher S.; Nagar, Bhushan

2013-01-01

Summary Death-associated protein 5 (DAP5/p97) is a homolog of the eukaryotic initiation factor 4G (eIF4G) that promotes the IRES-driven translation of multiple cellular mRNAs. Central to its function is the middle domain (MIF4G), which recruits the RNA helicase eIF4A. The middle domain of eIF4G consists of tandem HEAT repeats that coalesce to form a solenoid-type structure. Here, we report the crystal structure of the DAP5 MIF4G domain. Its overall fold is very similar to that of eIF4G, however, significant conformational variations impart distinct surface properties that could explain the observed differences in IRES binding between the two proteins. Interestingly, quantitative analysis of the DAP5-eIF4A interaction using isothermal titration calorimetry reveals a 10-fold lower affinity than with the eIF4G-eIF4A interaction that appears to affect their ability to stimulate eIF4A RNA unwinding activity in vitro. This difference in stability of the complex may have functional implications in selecting the mode of translation initiation. PMID:23478064

Protein phosphatase PPM1G regulates protein translation and cell growth by dephosphorylating 4E binding protein 1 (4E-BP1).

PubMed

Liu, Jianyu; Stevens, Payton D; Eshleman, Nichole E; Gao, Tianyan

2013-08-09

Protein translation initiation is a tightly controlled process responding to nutrient availability and mitogen stimulation. Serving as one of the most important negative regulators of protein translation, 4E binding protein 1 (4E-BP1) binds to translation initiation factor 4E and inhibits cap-dependent translation in a phosphorylation-dependent manner. Although it has been demonstrated previously that the phosphorylation of 4E-BP1 is controlled by mammalian target of rapamycin in the mammalian target of rapamycin complex 1, the mechanism underlying the dephosphorylation of 4E-BP1 remains elusive. Here, we report the identification of PPM1G as the phosphatase of 4E-BP1. A coimmunoprecipitation experiment reveals that PPM1G binds to 4E-BP1 in cells and that purified PPM1G dephosphorylates 4E-BP1 in vitro. Knockdown of PPM1G in 293E and colon cancer HCT116 cells results in an increase in the phosphorylation of 4E-BP1 at both the Thr-37/46 and Ser-65 sites. Furthermore, the time course of 4E-BP1 dephosphorylation induced by amino acid starvation or mammalian target of rapamycin inhibition is slowed down significantly in PPM1G knockdown cells. Functionally, the amount of 4E-BP1 bound to the cap-dependent translation initiation complex is decreased when the expression of PPM1G is depleted. As a result, the rate of cap-dependent translation, cell size, and protein content are increased in PPM1G knockdown cells. Taken together, our study has identified protein phosphatase PPM1G as a novel regulator of cap-dependent protein translation by negatively controlling the phosphorylation of 4E-BP1.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sekiyama, Naotaka; Arthanari, Haribabu; Papadopoulos, Evangelos

The eIF4E-binding protein (4E-BP) is a phosphorylation-dependent regulator of protein synthesis. The nonphosphorylated or minimally phosphorylated form binds translation initiation factor 4E (eIF4E), preventing binding of eIF4G and the recruitment of the small ribosomal subunit. Signaling events stimulate serial phosphorylation of 4E-BP, primarily by mammalian target of rapamycin complex 1 (mTORC1) at residues T 37/T 46, followed by T 70 and S 65. Hyperphosphorylated 4E-BP dissociates from eIF4E, allowing eIF4E to interact with eIF4G and translation initiation to resume. Because overexpression of eIF4E is linked to cellular transformation, 4E-BP is a tumor suppressor, and up-regulation of its activity is amore » goal of interest for cancer therapy. A recently discovered small molecule, eIF4E/eIF4G interaction inhibitor 1 (4EGI-1), disrupts the eIF4E/eIF4G interaction and promotes binding of 4E-BP1 to eIF4E. Structures of 14- to 16-residue 4E-BP fragments bound to eIF4E contain the eIF4E consensus binding motif, 54YXXXXLΦ 60 (motif 1) but lack known phosphorylation sites. We report in this paper a 2.1-Å crystal structure of mouse eIF4E in complex with m 7GTP and with a fragment of human 4E-BP1, extended C-terminally from the consensus-binding motif (4E-BP1 50–84). The extension, which includes a proline-turn-helix segment (motif 2) followed by a loop of irregular structure, reveals the location of two phosphorylation sites (S 65 and T 70). Our major finding is that the C-terminal extension (motif 3) is critical to 4E-BP1–mediated cell cycle arrest and that it partially overlaps with the binding site of 4EGI-1. Finally, the binding of 4E-BP1 and 4EGI-1 to eIF4E is therefore not mutually exclusive, and both ligands contribute to shift the equilibrium toward the inhibition of translation initiation.« less

Cytoplasmic E2f4 forms organizing centres for initiation of centriole amplification during multiciliogenesis

PubMed Central

Mori, Munemasa; Hazan, Renin; Danielian, Paul S.; Mahoney, John E.; Li, Huijun; Lu, Jining; Miller, Emily S.; Zhu, Xueliang; Lees, Jacqueline A.; Cardoso, Wellington V.

2017-01-01

Abnormal development of multiciliated cells is a hallmark of a variety of human conditions associated with chronic airway diseases, hydrocephalus and infertility. Multiciliogenesis requires both activation of a specialized transcriptional program and assembly of cytoplasmic structures for large-scale centriole amplification that generates basal bodies. It remains unclear, however, what mechanism initiates formation of these multiprotein complexes in epithelial progenitors. Here we show that this is triggered by nucleocytoplasmic translocation of the transcription factor E2f4. After inducing a transcriptional program of centriole biogenesis, E2f4 forms apical cytoplasmic organizing centres for assembly and nucleation of deuterosomes. Using genetically altered mice and E2F4 mutant proteins we demonstrate that centriole amplification is crucially dependent on these organizing centres and that, without cytoplasmic E2f4, deuterosomes are not assembled, halting multiciliogenesis. Thus, E2f4 integrates nuclear and previously unsuspected cytoplasmic events of centriole amplification, providing new perspectives for the understanding of normal ciliogenesis, ciliopathies and cancer. PMID:28675157

Mammalian poly(A)-binding protein is a eukaryotic translation initiation factor, which acts via multiple mechanisms.

PubMed

Kahvejian, Avak; Svitkin, Yuri V; Sukarieh, Rami; M'Boutchou, Marie-Noël; Sonenberg, Nahum

2005-01-01

Translation initiation is a multistep process involving several canonical translation factors, which assemble at the 5'-end of the mRNA to promote the recruitment of the ribosome. Although the 3' poly(A) tail of eukaryotic mRNAs and its major bound protein, the poly(A)-binding protein (PABP), have been studied extensively, their mechanism of action in translation is not well understood and is confounded by differences between in vivo and in vitro systems. Here, we provide direct evidence for the involvement of PABP in key steps of the translation initiation pathway. Using a new technique to deplete PABP from mammalian cell extracts, we show that extracts lacking PABP exhibit dramatically reduced rates of translation, reduced efficiency of 48S and 80S ribosome initiation complex formation, and impaired interaction of eIF4E with the mRNA cap structure. Supplementing PABP-depleted extracts with wild-type PABP completely rectified these deficiencies, whereas a mutant of PABP, M161A, which is incapable of interacting with eIF4G, failed to restore translation. In addition, a stronger inhibition (approximately twofold) of 80S as compared to 48S ribosome complex formation (approximately 65% vs. approximately 35%, respectively) by PABP depletion suggests that PABP plays a direct role in 60S subunit joining. PABP can thus be considered a canonical translation initiation factor, integral to initiation complex formation at the 5'-end of mRNA.

Mammalian poly(A)-binding protein is a eukaryotic translation initiation factor, which acts via multiple mechanisms

PubMed Central

Kahvejian, Avak; Svitkin, Yuri V.; Sukarieh, Rami; M'Boutchou, Marie-Noël; Sonenberg, Nahum

2005-01-01

Translation initiation is a multistep process involving several canonical translation factors, which assemble at the 5′-end of the mRNA to promote the recruitment of the ribosome. Although the 3′ poly(A) tail of eukaryotic mRNAs and its major bound protein, the poly(A)-binding protein (PABP), have been studied extensively, their mechanism of action in translation is not well understood and is confounded by differences between in vivo and in vitro systems. Here, we provide direct evidence for the involvement of PABP in key steps of the translation initiation pathway. Using a new technique to deplete PABP from mammalian cell extracts, we show that extracts lacking PABP exhibit dramatically reduced rates of translation, reduced efficiency of 48S and 80S ribosome initiation complex formation, and impaired interaction of eIF4E with the mRNA cap structure. Supplementing PABP-depleted extracts with wild-type PABP completely rectified these deficiencies, whereas a mutant of PABP, M161A, which is incapable of interacting with eIF4G, failed to restore translation. In addition, a stronger inhibition (approximately twofold) of 80S as compared to 48S ribosome complex formation (∼65% vs. ∼35%, respectively) by PABP depletion suggests that PABP plays a direct role in 60S subunit joining. PABP can thus be considered a canonical translation initiation factor, integral to initiation complex formation at the 5′-end of mRNA. PMID:15630022

Signalling to eIF4E in cancer

PubMed Central

Siddiqui, Nadeem; Sonenberg, Nahum

2015-01-01

Translational control plays a critical role in the regulation of gene expression in eukaryotes and affects many essential cellular processes, including proliferation, apoptosis and differentiation. Under most circumstances, translational control occurs at the initiation step at which the ribosome is recruited to the mRNA. The eukaryotic translation initiation factor 4E (eIF4E), as part of the eIF4F complex, interacts first with the mRNA and facilitates the recruitment of the 40S ribosomal subunit. The activity of eIF4E is regulated at many levels, most profoundly by two major signalling pathways: PI3K (phosphoinositide 3-kinase)/Akt (also known and Protein Kinase B, PKB)/mTOR (mechanistic/mammalian target of rapamycin) and Ras (rat sarcoma)/MAPK (mitogen-activated protein kinase)/Mnk (MAPK-interacting kinases). mTOR directly phosphorylates the 4E-BPs (eIF4E-binding proteins), which are inhibitors of eIF4E, to relieve translational suppression, whereas Mnk phosphorylates eIF4E to stimulate translation. Hyperactivation of these pathways occurs in the majority of cancers, which results in increased eIF4E activity. Thus, translational control via eIF4E acts as a convergence point for hyperactive signalling pathways to promote tumorigenesis. Consequently, recent works have aimed to target these pathways and ultimately the translational machinery for cancer therapy. PMID:26517881

Crystallization and preliminary X-ray analysis of eukaryotic initiation factor 4E from Pisum sativum

PubMed Central

Ashby, Jamie A.; Stevenson, Clare E. M.; Maule, Andrew J.; Lawson, David M.

2009-01-01

Crystals of an N-terminally truncated 20 kDa fragment of Pisum sativum eIF4E (ΔN-eIF4E) were grown by vapour diffusion. X-ray data were recorded to a resolution of 2.2 Å from a single crystal in-house. Indexing was consistent with primitive monoclinic symmetry and solvent-content estimations suggested that between four and nine copies of the eIF4E fragment were possible per crystallographic asymmetric unit. eIF4E is an essential component of the eukaryotic translation machinery and recent studies have shown that point mutations of plant eIF4Es can confer resistance to potyvirus infection. PMID:19652353

mRNA-Selective Translation Induced by FSH in Primary Sertoli Cells

PubMed Central

Musnier, Astrid; León, Kelly; Morales, Julia; Reiter, Eric; Boulo, Thomas; Costache, Vlad; Vourc'h, Patrick; Heitzler, Domitille; Oulhen, Nathalie; Poupon, Anne; Boulben, Sandrine; Cormier, Patrick

2012-01-01

FSH is a key hormonal regulator of Sertoli cell secretory activity, required to optimize sperm production. To fulfil its biological function, FSH binds a G protein-coupled receptor, the FSH-R. The FSH-R-transduced signaling network ultimately leads to the transcription or down-regulation of numerous genes. In addition, recent evidence has suggested that FSH might also regulate protein translation. However, this point has never been demonstrated conclusively yet. Here we have addressed this issue in primary rat Sertoli cells endogenously expressing physiological levels of FSH-R. We observed that, within 90 min of stimulation, FSH not only enhanced overall protein synthesis in a mammalian target of rapamycin-dependent manner but also increased the recruitment of mRNA to polysomes. m7GTP pull-down experiments revealed the functional recruitment of mammalian target of rapamycin and p70 S6 kinase to the 5′cap, further supported by the enhanced phosphorylation of one of p70 S6 kinase targets, the eukaryotic initiation factor 4B. Importantly, the scaffolding eukaryotic initiation factor 4G was also recruited, whereas eukaryotic initiation factor 4E-binding protein, the eukaryotic initiation factor 4E generic inhibitor, appeared to play a minor role in translational regulations induced by FSH, in contrast to what is generally observed in response to anabolic factors. This particular regulation of the translational machinery by FSH stimulation might support mRNA-selective translation, as shown here by quantitative RT-PCR amplification of the c-fos and vascular endothelial growth factor mRNA but not of all FSH target mRNA, in polysomal fractions. These findings add a new level of complexity to FSH biological roles in its natural target cells, which has been underappreciated so far. PMID:22383463

The alveolate translation initiation factor 4E family reveals a custom toolkit for translational control in core dinoflagellates.

PubMed

Jones, Grant D; Williams, Ernest P; Place, Allen R; Jagus, Rosemary; Bachvaroff, Tsvetan R

2015-02-10

Dinoflagellates are eukaryotes with unusual cell biology and appear to rely on translational rather than transcriptional control of gene expression. The eukaryotic translation initiation factor 4E (eIF4E) plays an important role in regulating gene expression because eIF4E binding to the mRNA cap is a control point for translation. eIF4E is part of an extended, eukaryote-specific family with different members having specific functions, based on studies of model organisms. Dinoflagellate eIF4E diversity could provide a mechanism for dinoflagellates to regulate gene expression in a post-transcriptional manner. Accordingly, eIF4E family members from eleven core dinoflagellate transcriptomes were surveyed to determine the diversity and phylogeny of the eIF4E family in dinoflagellates and related lineages including apicomplexans, ciliates and heterokonts. The survey uncovered eight to fifteen (on average eleven) different eIF4E family members in each core dinoflagellate species. The eIF4E family members from heterokonts and dinoflagellates segregated into three clades, suggesting at least three eIF4E cognates were present in their common ancestor. However, these three clades are distinct from the three previously described eIF4E classes, reflecting diverse approaches to a central eukaryotic function. Heterokonts contain four clades, ciliates two and apicomplexans only a single recognizable eIF4E clade. In the core dinoflagellates, the three clades were further divided into nine sub-clades based on the phylogenetic analysis and species representation. Six of the sub-clades included at least one member from all eleven core dinoflagellate species, suggesting duplication in their shared ancestor. Conservation within sub-clades varied, suggesting different selection pressures. Phylogenetic analysis of eIF4E in core dinoflagellates revealed complex layering of duplication and conservation when compared to other eukaryotes. Our results suggest that the diverse eIF4E family in core dinoflagellates may provide a toolkit to enable selective translation as a strategy for controlling gene expression in these enigmatic eukaryotes.

Amino Acid Availability and Age Affect the Leucine Stimulation of Protein Synthesis and eIF4F Formation in Muscle

PubMed Central

Escobar, Jeffery; Frank, Jason W.; Suryawan, Agus; Nguyen, Hanh V.; Davis, Teresa A.

2009-01-01

We have previously shown that a physiological increase in plasma leucine for 60- and 120-min increases translation initiation factor activation in muscle of neonatal pigs. Although muscle protein synthesis is increased by leucine at 60 min, it is not maintained at 120 min, perhaps due to the decrease in plasma amino acids (AA). In the current study, 7- and 26-day-old pigs were fasted overnight and infused with leucine (0 or 400 µmol· kg−1· h−1) for 120 min to raise leucine within the postprandial range. The leucine was infused in the presence or absence of a replacement AA mixture (without leucine) to maintain baseline plasma AA levels. AA administration prevented the leucine-induced reduction in plasma AA in both age groups. At 7 days, leucine infusion alone increased eukaryotic initiation factor (eIF) 4E binding protein-1 (4E-BP1) phosphorylation, decreased inactive 4E-BP1·eIF4E complex abundance, and increased active eIF4G·eIF4E complex formation in skeletal muscle; leucine infusion with replacement AA also stimulated these, as well as S6K1, rpS6, and eIF4G phosphorylation. At 26 days, leucine infusion alone increased 4E-BP1 phosphorylation and decreased the inactive 4E-BP1·eIF4E complex only; leucine with AA also stimulated these, as well as S6K1 and rpS6 phosphorylation. Muscle protein synthesis was increased in 7-day-old (+60%) and 26-day-old (+40%) pigs infused with leucine and replacement AA, but not with leucine alone. Thus, the ability of leucine to stimulate eIF4F formation and protein synthesis in skeletal muscle is dependent on AA availability and age. PMID:17878223

Molecular mechanism of the dual activity of 4EGI-1: Dissociating eIF4G from eIF4E but stabilizing the binding of unphosphorylated 4E-BP1

DOE PAGES

Sekiyama, Naotaka; Arthanari, Haribabu; Papadopoulos, Evangelos; ...

2015-07-13

The eIF4E-binding protein (4E-BP) is a phosphorylation-dependent regulator of protein synthesis. The nonphosphorylated or minimally phosphorylated form binds translation initiation factor 4E (eIF4E), preventing binding of eIF4G and the recruitment of the small ribosomal subunit. Signaling events stimulate serial phosphorylation of 4E-BP, primarily by mammalian target of rapamycin complex 1 (mTORC1) at residues T 37/T 46, followed by T 70 and S 65. Hyperphosphorylated 4E-BP dissociates from eIF4E, allowing eIF4E to interact with eIF4G and translation initiation to resume. Because overexpression of eIF4E is linked to cellular transformation, 4E-BP is a tumor suppressor, and up-regulation of its activity is amore » goal of interest for cancer therapy. A recently discovered small molecule, eIF4E/eIF4G interaction inhibitor 1 (4EGI-1), disrupts the eIF4E/eIF4G interaction and promotes binding of 4E-BP1 to eIF4E. Structures of 14- to 16-residue 4E-BP fragments bound to eIF4E contain the eIF4E consensus binding motif, 54YXXXXLΦ 60 (motif 1) but lack known phosphorylation sites. We report in this paper a 2.1-Å crystal structure of mouse eIF4E in complex with m 7GTP and with a fragment of human 4E-BP1, extended C-terminally from the consensus-binding motif (4E-BP1 50–84). The extension, which includes a proline-turn-helix segment (motif 2) followed by a loop of irregular structure, reveals the location of two phosphorylation sites (S 65 and T 70). Our major finding is that the C-terminal extension (motif 3) is critical to 4E-BP1–mediated cell cycle arrest and that it partially overlaps with the binding site of 4EGI-1. Finally, the binding of 4E-BP1 and 4EGI-1 to eIF4E is therefore not mutually exclusive, and both ligands contribute to shift the equilibrium toward the inhibition of translation initiation.« less

Downregulated Translation Initiation Signaling Predisposes Low-Birth-Weight Neonatal Pigs to Slower Rates of Muscle Protein Synthesis

PubMed Central

Chen, Ying; McCauley, Sydney R.; Johnson, Sally E.; Rhoads, Robert P.; El-Kadi, Samer W.

2017-01-01

Low-birth-weight (LBWT) neonates experience restricted muscle growth in their perinatal life. Our aim was to investigate the mechanisms that contribute to slower skeletal muscle growth of LBWT neonatal pigs. Twenty-four 1-day old male LBWT (816 ± 55 g) and normal-birth-weight (NBWT; 1,642 ± 55 g) littermates (n = 12) were euthanized to collect blood and longissimus dorsi (LD) muscle subsamples. Plasma glucose, insulin, and insulin-like growth factor-I (IGF-I) were lower in LBWT compared with NBWT pigs. Muscle IGF-I mRNA expression were lower in LBWT than NBWT pigs. However, IGF-I receptor mRNA and protein abundance was greater in LD of LBWT pigs. Abundance of myostatin and its receptors, and abundance and phosphorylation of smad3 were lower in LBWT LD by comparison with NBWT LD. Abundance of eukaryotic initiation factor (eIF) 4E binding protein 1 and mitogen-activated protein kinase-interacting kinases was lower in muscle of LBWT pigs compared with NBWT siblings, while eIF4E abundance and phosphorylation did not differ between the two groups. Furthermore, phosphorylation of ribosomal protein S6 kinase 1 (S6K1) was less in LBWT muscle, possibly due to lower eIF3e abundance. In addition, abundance and phosphorylation of eIF4G was reduced in LBWT pigs by comparison with NBWT littermates, suggesting translation initiation complex formation is compromised in muscle of LBWT pigs. In conclusion, diminished S6K1 activation and translation initiation signaling are likely the major contributors to impaired muscle growth in LBWT neonatal pigs. The upregulated IGF-I R expression and downregulated myostatin signaling seem to be compensatory responses for the reduction in protein synthesis signaling. PMID:28744224

Stress Granule-Inducing Eukaryotic Translation Initiation Factor 4A Inhibitors Block Influenza A Virus Replication

PubMed Central

Slaine, Patrick D.; Kleer, Mariel; Smith, Nathan K.; Khaperskyy, Denys A.

2017-01-01

Eukaryotic translation initiation factor 4A (eIF4A) is a helicase that facilitates assembly of the translation preinitiation complex by unwinding structured mRNA 5′ untranslated regions. Pateamine A (PatA) and silvestrol are natural products that disrupt eIF4A function and arrest translation, thereby triggering the formation of cytoplasmic aggregates of stalled preinitiation complexes known as stress granules (SGs). Here we examined the effects of eIF4A inhibition by PatA and silvestrol on influenza A virus (IAV) protein synthesis and replication in cell culture. Treatment of infected cells with either PatA or silvestrol at early times post-infection resulted in SG formation, arrest of viral protein synthesis and failure to replicate the viral genome. PatA, which irreversibly binds to eIF4A, sustained long-term blockade of IAV replication following drug withdrawal, and inhibited IAV replication at concentrations that had minimal cytotoxicity. By contrast, the antiviral effects of silvestrol were fully reversible; drug withdrawal caused rapid SG dissolution and resumption of viral protein synthesis. IAV inhibition by silvestrol was invariably associated with cytotoxicity. PatA blocked replication of genetically divergent IAV strains, suggesting common dependence on host eIF4A activity. This study demonstrates that the core host protein synthesis machinery can be targeted to block viral replication. PMID:29258238

mTORC1 and CK2 coordinate ternary and eIF4F complex assembly

PubMed Central

Gandin, Valentina; Masvidal, Laia; Cargnello, Marie; Gyenis, Laszlo; McLaughlan, Shannon; Cai, Yutian; Tenkerian, Clara; Morita, Masahiro; Balanathan, Preetika; Jean-Jean, Olivier; Stambolic, Vuk; Trost, Matthias; Furic, Luc; Larose, Louise; Koromilas, Antonis E.; Asano, Katsura; Litchfield, David; Larsson, Ola; Topisirovic, Ivan

2016-01-01

Ternary complex (TC) and eIF4F complex assembly are the two major rate-limiting steps in translation initiation regulated by eIF2α phosphorylation and the mTOR/4E-BP pathway, respectively. How TC and eIF4F assembly are coordinated, however, remains largely unknown. We show that mTOR suppresses translation of mRNAs activated under short-term stress wherein TC recycling is attenuated by eIF2α phosphorylation. During acute nutrient or growth factor stimulation, mTORC1 induces eIF2β phosphorylation and recruitment of NCK1 to eIF2, decreases eIF2α phosphorylation and bolsters TC recycling. Accordingly, eIF2β mediates the effect of mTORC1 on protein synthesis and proliferation. In addition, we demonstrate a formerly undocumented role for CK2 in regulation of translation initiation, whereby CK2 stimulates phosphorylation of eIF2β and simultaneously bolsters eIF4F complex assembly via the mTORC1/4E-BP pathway. These findings imply a previously unrecognized mode of translation regulation, whereby mTORC1 and CK2 coordinate TC and eIF4F complex assembly to stimulate cell proliferation. PMID:27040916

E1(-)E4(+) adenoviral gene transfer vectors function as a "pro-life" signal to promote survival of primary human endothelial cells.

PubMed

Ramalingam, R; Rafii, S; Worgall, S; Brough, D E; Crystal, R G

1999-05-01

Although endothelial cells are quiescent and long-lived in vivo, when they are removed from blood vessels and cultured in vitro they die within days to weeks. In studies of the interaction of E1(-)E4(+) replication-deficient adenovirus (Ad) vectors and human endothelium, the cells remained quiescent and were viable for prolonged periods. Evaluation of these cultures showed that E1(-)E4(+) Ad vectors provide an "antiapoptotic" signal that, in association with an increase in the ratio of Bcl2 to Bax levels, induces the endothelial cells to enter a state of "suspended animation," remaining viable for at least 30 days, even in the absence of serum and growth factors. Although the mechanisms initiating these events are unclear, the antiapoptoic signal requires the presence of E4 genes in the vector genome, suggesting that one or more E4 open reading frames of subgroup C Ad initiate a "pro-life" program that modifies cultured endothelial cells to survive for prolonged periods.

Recessive Resistance to Plant Viruses: Potential Resistance Genes Beyond Translation Initiation Factors

PubMed Central

Hashimoto, Masayoshi; Neriya, Yutaro; Yamaji, Yasuyuki; Namba, Shigetou

2016-01-01

The ability of plant viruses to propagate their genomes in host cells depends on many host factors. In the absence of an agrochemical that specifically targets plant viral infection cycles, one of the most effective methods for controlling viral diseases in plants is taking advantage of the host plant’s resistance machinery. Recessive resistance is conferred by a recessive gene mutation that encodes a host factor critical for viral infection. It is a branch of the resistance machinery and, as an inherited characteristic, is very durable. Moreover, recessive resistance may be acquired by a deficiency in a negative regulator of plant defense responses, possibly due to the autoactivation of defense signaling. Eukaryotic translation initiation factor (eIF) 4E and eIF4G and their isoforms are the most widely exploited recessive resistance genes in several crop species, and they are effective against a subset of viral species. However, the establishment of efficient, recessive resistance-type antiviral control strategies against a wider range of plant viral diseases requires genetic resources other than eIF4Es. In this review, we focus on recent advances related to antiviral recessive resistance genes evaluated in model plants and several crop species. We also address the roles of next-generation sequencing and genome editing technologies in improving plant genetic resources for recessive resistance-based antiviral breeding in various crop species. PMID:27833593

Role of the Phosphoinositide 3-Kinase-Akt-Mammalian Target of the Rapamycin Signaling Pathway in Long-Term Potentiation and Trace Fear Conditioning Memory in Rat Medial Prefrontal Cortex

ERIC Educational Resources Information Center

Sui, Li; Wang, Jing; Li, Bao-Ming

2008-01-01

Phosphatidylinositol 3-kinase (PI3K) and its downstream targets, including Akt (also known as protein kinase B, PKB), mammalian target of rapamycin (mTOR), the 70-kDa ribosomal S6 kinase (p70S6k), and the eukaryotic initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1), may play important roles in long-term synaptic plasticity and memory in many…

Regulation of Torpor in the Gray Mouse Lemur: Transcriptional and Translational Controls and Role of AMPK Signaling.

PubMed

Zhang, Jing; Tessier, Shannon N; Biggar, Kyle K; Wu, Cheng-Wei; Pifferi, Fabien; Perret, Martine; Storey, Kenneth B

2015-04-01

The gray mouse lemur (Microcebus murinus) is one of few primate species that is able to enter daily torpor or prolonged hibernation in response to environmental stresses. With an emerging significance to human health research, lemurs present an optimal model for exploring molecular adaptations that regulate primate hypometabolism. A fundamental challenge is how to effectively regulate energy expensive cellular processes (e.g., transcription and translation) during transitions to/from torpor without disrupting cellular homeostasis. One such regulatory mechanism is reversible posttranslational modification of selected protein targets that offers fine cellular control without the energetic burden. This study investigates the role of phosphorylation and/or acetylation in regulating key factors involved in energy homeostasis (AMP-activated protein kinase, or AMPK, signaling pathway), mRNA translation (eukaryotic initiation factor 2α or eIF2α, eukaryotic initiation factor 4E or eIF4E, and initiation factor 4E binding protein or 4EBP), and gene transcription (histone H3) in six tissues of torpid and aroused gray mouse lemurs. Our results indicated selective tissue-specific changes of these regulatory proteins. The relative level of Thr172-phosphorylated AMPKα was significantly elevated in the heart but reduced in brown adipose tissue during daily torpor, as compared to the aroused lemurs, implicating the regulation of AMPK activity during daily torpor in these tissues. Interestingly, the levels of the phosphorylated eIFs were largely unaltered between aroused and torpid animals. Phosphorylation and acetylation of histone H3 were examined as a marker for transcriptional regulation. Compared to the aroused lemurs, level of Ser10-phosphorylated histone H3 decreased significantly in white adipose tissue during torpor, suggesting global suppression of gene transcription. However, a significant increase in acetyl-histone H3 in the heart of torpid lemurs indicated a possible stimulation of transcriptional activity of this tissue. Overall, our study demonstrates that AMPK signaling and posttranslational regulation of selected proteins may play crucial roles in the control of transcription/translation during daily torpor in mouse lemurs. Copyright © 2015. Production and hosting by Elsevier Ltd.

IRES-mediated translation of foot-and-mouth disease virus (FMDV) in cultured cells derived from FMDV-susceptible and -insusceptible animals.

PubMed

Kanda, Takehiro; Ozawa, Makoto; Tsukiyama-Kohara, Kyoko

2016-03-31

Foot-and-mouth disease virus (FMDV) possess a positive sense, single stranded RNA genome. Internal ribosomal entry site (IRES) element exists within its 5' untranslated region (5'UTR) of the viral RNA. Translation of the viral RNA is initiated by internal entry of the 40S ribosome within the IRES element. This process is facilitated by cellular factors known as IRES trans-acting factors (ITAFs). Foot-and-mouth disease (FMD) is host-restricted disease for cloven-hoofed animals such as cattle and pigs, but the factors determining the host range have not been identified yet. Although, ITAFs are known to promote IRES-mediated translation, these findings were confirmed only in cells derived from FMDV-insusceptible animals so far. We evaluated and compared the IRES-mediated translation activities among cell lines derived from four different animal species using bicistronic luciferase reporter plasmid, which possesses an FMDV-IRES element between Renilla and Firefly luciferase genes. Furthermore, we analyzed the effect of the cellular factors on IRES-mediated translation by silencing the cellular factors using siRNA in both FMDV-susceptible and -insusceptible animal cells. Our data indicated that IRES-mediated translational activity was not linked to FMDV host range. ITAF45 promoted IRES-mediated translation in all cell lines, and the effects of poly-pyrimidine tract binding protein (PTB) and eukaryotic initiation factor 4E-binding protein 1 (4E-BP1) were observed only in FMDV-susceptible cells. Thus, PTB and 4E-BP1 may influence the host range of FMDV. IRES-mediated translation activity of FMDV was not predictive of its host range. ITAF45 promoted IRES-mediated translation in all cells, and the effects of PTB and 4E-BP1 were observed only in FMDV-susceptible cells.

Nat1 promotes translation of specific proteins that induce differentiation of mouse embryonic stem cells.

PubMed

Sugiyama, Hayami; Takahashi, Kazutoshi; Yamamoto, Takuya; Iwasaki, Mio; Narita, Megumi; Nakamura, Masahiro; Rand, Tim A; Nakagawa, Masato; Watanabe, Akira; Yamanaka, Shinya

2017-01-10

Novel APOBEC1 target 1 (Nat1) (also known as "p97," "Dap5," and "Eif4g2") is a ubiquitously expressed cytoplasmic protein that is homologous to the C-terminal two thirds of eukaryotic translation initiation factor 4G (Eif4g1). We previously showed that Nat1-null mouse embryonic stem cells (mES cells) are resistant to differentiation. In the current study, we found that NAT1 and eIF4G1 share many binding proteins, such as the eukaryotic translation initiation factors eIF3 and eIF4A and ribosomal proteins. However, NAT1 did not bind to eIF4E or poly(A)-binding proteins, which are critical for cap-dependent translation initiation. In contrast, compared with eIF4G1, NAT1 preferentially interacted with eIF2, fragile X mental retardation proteins (FMR), and related proteins and especially with members of the proline-rich and coiled-coil-containing protein 2 (PRRC2) family. We also found that Nat1-null mES cells possess a transcriptional profile similar, although not identical, to the ground state, which is established in wild-type mES cells when treated with inhibitors of the ERK and glycogen synthase kinase 3 (GSK3) signaling pathways. In Nat1-null mES cells, the ERK pathway is suppressed even without inhibitors. Ribosome profiling revealed that translation of mitogen-activated protein kinase kinase kinase 3 (Map3k3) and son of sevenless homolog 1 (Sos1) is suppressed in the absence of Nat1 Forced expression of Map3k3 induced differentiation of Nat1-null mES cells. These data collectively show that Nat1 is involved in the translation of proteins that are required for cell differentiation.

Defects in tRNA processing and nuclear export induce GCN4 translation independently of phosphorylation of the alpha subunit of eukaryotic translation initiation factor 2.

PubMed

Qiu, H; Hu, C; Anderson, J; Björk, G R; Sarkar, S; Hopper, A K; Hinnebusch, A G

2000-04-01

Induction of GCN4 translation in amino acid-starved cells involves the inhibition of initiator tRNA(Met) binding to eukaryotic translation initiation factor 2 (eIF2) in response to eIF2 phosphorylation by protein kinase GCN2. It was shown previously that GCN4 translation could be induced independently of GCN2 by overexpressing a mutant tRNA(AAC)(Val) (tRNA(Val*)) or the RNA component of RNase MRP encoded by NME1. Here we show that overexpression of the tRNA pseudouridine 55 synthase encoded by PUS4 also leads to translational derepression of GCN4 (Gcd(-) phenotype) independently of eIF2 phosphorylation. Surprisingly, the Gcd(-) phenotype of high-copy-number PUS4 (hcPUS4) did not require PUS4 enzymatic activity, and several lines of evidence indicate that PUS4 overexpression did not diminish functional initiator tRNA(Met) levels. The presence of hcPUS4 or hcNME1 led to the accumulation of certain tRNA precursors, and their Gcd(-) phenotypes were reversed by overexpressing the RNA component of RNase P (RPR1), responsible for 5'-end processing of all tRNAs. Consistently, overexpression of a mutant pre-tRNA(Tyr) that cannot be processed by RNase P had a Gcd(-) phenotype. Interestingly, the Gcd(-) phenotype of hcPUS4 also was reversed by overexpressing LOS1, required for efficient nuclear export of tRNA, and los1Delta cells have a Gcd(-) phenotype. Overproduced PUS4 appears to impede 5'-end processing or export of certain tRNAs in the nucleus in a manner remedied by increased expression of RNase P or LOS1, respectively. The mutant tRNA(Val*) showed nuclear accumulation in otherwise wild-type cells, suggesting a defect in export to the cytoplasm. We propose that yeast contains a nuclear surveillance system that perceives defects in processing or export of tRNA and evokes a reduction in translation initiation at the step of initiator tRNA(Met) binding to the ribosome.

Defects in tRNA Processing and Nuclear Export Induce GCN4 Translation Independently of Phosphorylation of the α Subunit of Eukaryotic Translation Initiation Factor 2

PubMed Central

Qiu, Hongfang; Hu, Cuihua; Anderson, James; Björk, Glenn R.; Sarkar, Srimonti; Hopper, Anita K.; Hinnebusch, Alan G.

2000-01-01

Induction of GCN4 translation in amino acid-starved cells involves the inhibition of initiator tRNAMet binding to eukaryotic translation initiation factor 2 (eIF2) in response to eIF2 phosphorylation by protein kinase GCN2. It was shown previously that GCN4 translation could be induced independently of GCN2 by overexpressing a mutant tRNAAACVal (tRNAVal*) or the RNA component of RNase MRP encoded by NME1. Here we show that overexpression of the tRNA pseudouridine 55 synthase encoded by PUS4 also leads to translational derepression of GCN4 (Gcd− phenotype) independently of eIF2 phosphorylation. Surprisingly, the Gcd− phenotype of high-copy-number PUS4 (hcPUS4) did not require PUS4 enzymatic activity, and several lines of evidence indicate that PUS4 overexpression did not diminish functional initiator tRNAMet levels. The presence of hcPUS4 or hcNME1 led to the accumulation of certain tRNA precursors, and their Gcd− phenotypes were reversed by overexpressing the RNA component of RNase P (RPR1), responsible for 5′-end processing of all tRNAs. Consistently, overexpression of a mutant pre-tRNATyr that cannot be processed by RNase P had a Gcd− phenotype. Interestingly, the Gcd− phenotype of hcPUS4 also was reversed by overexpressing LOS1, required for efficient nuclear export of tRNA, and los1Δ cells have a Gcd− phenotype. Overproduced PUS4 appears to impede 5′-end processing or export of certain tRNAs in the nucleus in a manner remedied by increased expression of RNase P or LOS1, respectively. The mutant tRNAVal* showed nuclear accumulation in otherwise wild-type cells, suggesting a defect in export to the cytoplasm. We propose that yeast contains a nuclear surveillance system that perceives defects in processing or export of tRNA and evokes a reduction in translation initiation at the step of initiator tRNAMet binding to the ribosome. PMID:10713174

Physical and Functional Interaction between the Eukaryotic Orthologs of Prokaryotic Translation Initiation Factors IF1 and IF2

PubMed Central

Choi, Sang Ki; Olsen, DeAnne S.; Roll-Mecak, Antonina; Martung, Agnes; Remo, Keith L.; Burley, Stephen K.; Hinnebusch, Alan G.; Dever, Thomas E.

2000-01-01

To initiate protein synthesis, a ribosome with bound initiator methionyl-tRNA must be assembled at the start codon of an mRNA. This process requires the coordinated activities of three translation initiation factors (IF) in prokaryotes and at least 12 translation initiation factors in eukaryotes (eIF). The factors eIF1A and eIF5B from eukaryotes show extensive amino acid sequence similarity to the factors IF1 and IF2 from prokaryotes. By a combination of two-hybrid, coimmunoprecipitation, and in vitro binding assays eIF1A and eIF5B were found to interact directly, and the eIF1A binding site was mapped to the C-terminal region of eIF5B. This portion of eIF5B was found to be critical for growth in vivo and for translation in vitro. Overexpression of eIF1A exacerbated the slow-growth phenotype of yeast strains expressing C-terminally truncated eIF5B. These findings indicate that the physical interaction between the evolutionarily conserved factors eIF1A and eIF5B plays an important role in translation initiation, perhaps to direct or stabilize the binding of methionyl-tRNA to the ribosomal P site. PMID:10982835

eIF4E Threshold Levels Differ in Governing Normal and Neoplastic Expansion of Mammary Stem and Luminal Progenitor cells

PubMed Central

Avdulov, Svetlana; Herrera, Jeremy; Smith, Karen; Peterson, Mark; Gomez-Garcia, Jose R.; Beadnell, Thomas C.; Schwertfeger, Kathryn L.; Benyumov, Alexey O.; Manivel, J. Carlos; Li, Shunan; Bielinsky, Anja-Katrin; Yee, Douglas; Bitterman, Peter B.; Polunovsky, Vitaly A.

2015-01-01

Translation initiation factor eIF4E mediates normal cell proliferation, yet induces tumorigenesis when overexpressed. The mechanisms by which eIF4E directs such distinct biological outputs remains unknown. We found that mouse mammary morphogenesis during pregnancy and lactation is accompanied by increased cap-binding capability of eIF4E and activation of the eIF4E-dependent translational apparatus, but only subtle oscillations in eIF4E abundance. Using a transgenic mouse model engineered so that lactogenic hormones stimulate a sustained increase in eIF4E abundance in stem/progenitor cells of lactogenic mammary epithelium during successive pregnancy/lactation cycles, eIF4E overexpression increased cell self-renewal, triggered DNA replication stress, and induced formation of pre-malignant and malignant lesions. Using complementary in vivo and ex vivo approaches, we found that increasing eIF4E levels rescued cells harboring oncogenic c-Myc or H-RasV12 from DNA replication stress and oncogene-induced replication catastrophe. Our findings indicate that distinct threshold levels of eIF4E govern its biological output in lactating mammary glands, and that eIF4E overexpression in the context of stem/progenitor cell population expansion can initiate malignant transformation by enabling cells to evade DNA damage checkpoints activated by oncogenic stimuli. Maintaining eIF4E levels below its pro-neoplastic threshold is an important anticancer defense in normal cells, with important implications for understanding pregnancy-associated breast cancer. PMID:25524901

eIF4E threshold levels differ in governing normal and neoplastic expansion of mammary stem and luminal progenitor cells.

PubMed

Avdulov, Svetlana; Herrera, Jeremy; Smith, Karen; Peterson, Mark; Gomez-Garcia, Jose R; Beadnell, Thomas C; Schwertfeger, Kathryn L; Benyumov, Alexey O; Manivel, J Carlos; Li, Shunan; Bielinsky, Anja-Katrin; Yee, Douglas; Bitterman, Peter B; Polunovsky, Vitaly A

2015-02-15

Translation initiation factor eIF4E mediates normal cell proliferation, yet induces tumorigenesis when overexpressed. The mechanisms by which eIF4E directs such distinct biologic outputs remain unknown. We found that mouse mammary morphogenesis during pregnancy and lactation is accompanied by increased cap-binding capability of eIF4E and activation of the eIF4E-dependent translational apparatus, but only subtle oscillations in eIF4E abundance. Using a transgenic mouse model engineered so that lactogenic hormones stimulate a sustained increase in eIF4E abundance in stem/progenitor cells of lactogenic mammary epithelium during successive pregnancy/lactation cycles, eIF4E overexpression increased self-renewal, triggered DNA replication stress, and induced formation of premalignant and malignant lesions. Using complementary in vivo and ex vivo approaches, we found that increasing eIF4E levels rescued cells harboring oncogenic c-Myc or H-RasV12 from DNA replication stress and oncogene-induced replication catastrophe. Our findings indicate that distinct threshold levels of eIF4E govern its biologic output in lactating mammary glands and that eIF4E overexpression in the context of stem/progenitor cell population expansion can initiate malignant transformation by enabling cells to evade DNA damage checkpoints activated by oncogenic stimuli. Maintaining eIF4E levels below its proneoplastic threshold is an important anticancer defense in normal cells, with important implications for understanding pregnancy-associated breast cancer. ©2014 American Association for Cancer Research.

Piwil2 is reactivated by HPV oncoproteins and initiates cell reprogramming via epigenetic regulation during cervical cancer tumorigenesis.

PubMed

Feng, Dingqing; Yan, Keqin; Zhou, Ying; Liang, Haiyan; Liang, Jing; Zhao, Weidong; Dong, Zhongjun; Ling, Bin

2016-10-04

The human papillomavirus (HPV) oncoproteins E6 and E7 are risk factors that are primarily responsible for the initiation and progression of cervical cancer, and they play a key role in immortalization and transformation by reprogramming differentiating host epithelial cells. It is unclear how cervical epithelial cells transform into tumor-initiating cells (TICs). Here, we observed that the germ stem cell protein Piwil2 is expressed in pre-cancerous and malignant lesions of the cervix and cervical cancer cell lines with the exception of the non-HPV-infected C33a cell line. Knockdown of Piwil2 by shRNA led to a marked reduction in proliferation and colony formation, in vivo tumorigenicity, chemo-resistance, and the proportion of cancer stem-like cells. In contrast, Piwil2 overexpression induced malignant transformation of HaCaT cells and the acquisition of tumor-initiating capabilities. Gene-set enrichment analysis revealed embryonic stem cell (ESC) identity, malignant biological behavior, and specifically, activation targets of the cell reprogramming factors c-Myc, Klf4, Nanog, Oct4, and Sox2 in Piwil2-overexpressing HaCaT cells. We further confirmed that E6 and E7 reactivated Piwil2 and that E6 and E7 overexpression resulted in a similar gene-set enrichment pattern as Piwil2 overexpression in HaCaT cells. Moreover, Piwil2 overexpression or E6 and E7 activation induced H3K9 acetylation but reduced H3K9 trimethylation, which contributed to the epigenetic reprogramming and ESC signature maintenance, as predicted previously. Our study demonstrates that Piwil2, reactivated by the HPV oncoproteins E6 and E7, plays an essential role in the transformation of cervical epithelial cells to TICs via epigenetics-based cell reprogramming.

Unphosphorylated HSP27 (HSPB1) regulates the translation initiation process via a direct association with eIF4E in osteoblasts.

PubMed

Kuroyanagi, Gen; Tokuda, Haruhiko; Yamamoto, Naohiro; Matsushima-Nishiwaki, Rie; Kozawa, Osamu; Otsuka, Takanobu

2015-09-01

Heat-shock protein 27 (HSP27/HSPB1) and its phosphorylation are implicated in multiple physiological and pathophysiological cell functions. Our previous study reported that unphosphorylated HSP27 has an inhibitory role in triiodothyronine (T(3))‑induced osteocalcin (OC) synthesis in osteoblasts. However, the mechanisms behind the HSP27‑mediated effects on osteoblasts remain to be clarified. In the present study, to investigate the exact mechanism of HSP27 and its phosphorylation in osteoblasts, the molecular targets of HSP27 were explored using osteoblast‑like MC3T3‑E1 cells. The levels of OC mRNA induced by T(3) in the HSP27‑overexpressing cells did not show any significant differences compared with those in the control empty vector‑transfected cells. Therefore, the interactions between HSP27 and translational molecules were focused on, including eukaryotic translation initiation factor 4E (eIF4E), eIF4G and 4E‑binding protein 1 (4E‑BP1). The HSP27 protein in the unstimulated cells co‑immunoprecipitated with eIF4E, but not eIF4G or 4E‑BP1. In addition, the association of eIF4E with 4E‑BP1 was observed in the HSP27‑overexpressing cells, as well as in the control cells. Under T(3) stimulation, the binding of eIF4E to eIF4G was markedly attenuated in the HSP27‑overexpressing cells compared with the control cells. In addition, the binding of HSP27 to eIF4E in the unstimulated cells was diminished by the phosphorylation of HSP27. In response to T(3) stimulation, the association of eIF4E with eIF4G in the unphosphorylatable HSP27‑overexpressing cells was markedly reduced compared with the phospho‑mimic HSP27‑overexpressing cells. Taken together, these findings strongly suggest that unphosphorylated HSP27 associates with eIF4E in osteoblasts and suppresses the translation initiation process.

Plant growth and fertility requires functional interactions between specific PABP and eIF4G gene family members

PubMed Central

2018-01-01

The initiation of protein synthesis requires the involvement of the eukaryotic translation initiation factor (eIF) 4G to promote assembly of the factors needed to recruit a 40S ribosomal subunit to an mRNA. Although many eukaryotes express two eIF4G isoforms that are highly similar, those in plants, referred to as eIF4G and eIFiso4G, are highly divergent in size, sequence, and domain organization. Species of the Brassicaceae and the Cleomaceae also express a divergent eIFiso4G isoform, referred to as eIFiso4G2, not found elsewhere in the plant kingdom. Despite their divergence, eIF4G and eIFiso4G interact with eIF4A, eIF4B, and eIF4E isoforms needed for binding an mRNA. eIF4G and eIFiso4G also interact with the poly(A)-binding protein (PABP) which promotes ribosome recruitment to an mRNA. Increasing the complexity of such an interaction, however, Arabidopsis also expresses three PABP isoforms (PAB2, PAB4, and PAB8) in vegetative and reproductive tissues. In this study, the functional interactions among the eIF4G and the widely-expressed PABP isoforms were examined. Loss of PAB2 or PAB8 in combination with loss of eIF4G or eIFiso4G had little to no effect on growth or fertility whereas pab2 pab8 eif4g or pab2 pab8 eifiso4g1/2 mutants exhibited smaller stature and reduced fertility. Although the pab4 eifiso4g1 mutant grows normally and is fertile, pab4 eif4g or pab4 eifiso4g2 mutants could not be isolated. Even pab4/PAB4 eif4g/eIF4G heterozygous plants exhibited growth defects and low fertility. Mutant co-inheritance analysis in reciprocal crosses with wild-type plants revealed that most ovaries and pollen from pab4/PAB4 eif4g/eIF4G plants were PAB4 eif4g. Similarly, co-inheritance studies with pab4/PAB4 eifiso4g2/eIFiso4G2 plants suggested most ovaries were PAB4 eifiso4g2. These results suggest that a functional interaction between PAB4 and eIF4G and between PAB4 and eIFiso4G2 is required for growth and normal fertility. PMID:29381712

Inhibition of Group I Metabotropic Glutamate Receptors Reverses Autistic-Like Phenotypes Caused by Deficiency of the Translation Repressor eIF4E Binding Protein 2

PubMed Central

Aguilar-Valles, Argel; Matta-Camacho, Edna; Khoutorsky, Arkady; Gkogkas, Christos; Nader, Karim

2015-01-01

Exacerbated mRNA translation during brain development has been linked to autism spectrum disorders (ASDs). Deletion of the eukaryotic initiation factor 4E (eIF4E)-binding protein 2 gene (Eif4ebp2), encoding the suppressor of mRNA translation initiation 4E-BP2, leads to an imbalance in excitatory-to-inhibitory neurotransmission and ASD-like behaviors. Inhibition of group I metabotropic glutamate receptors (mGluRs) mGluR1 and mGluR5 reverses the autistic phenotypes in several ASD mouse models. Importantly, these receptors control synaptic physiology via activation of mRNA translation. We investigated the potential reversal of autistic-like phenotypes in Eif4ebp2−/− mice by using antagonists of mGluR1 (JNJ16259685) or mGluR5 (fenobam). Augmented hippocampal mGluR-induced long-term depression (LTD; or chemically induced mGluR-LTD) in Eif4ebp2−/− mice was rescued by mGluR1 or mGluR5 antagonists. While rescue by mGluR5 inhibition occurs through the blockade of a protein synthesis-dependent component of LTD, normalization by mGluR1 antagonists requires the activation of protein synthesis. Synaptically induced LTD was deficient in Eif4ebp2−/− mice, and this deficit was not rescued by group I mGluR antagonists. Furthermore, a single dose of mGluR1 (0.3 mg/kg) or mGluR5 (3 mg/kg) antagonists in vivo reversed the deficits in social interaction and repetitive behaviors (marble burying) in Eif4ebp2−/− mice. Our results demonstrate that Eif4ebp2−/− mice serve as a relevant model to test potential therapies for ASD symptoms. In addition, we provide substantive evidence that the inhibition of mGluR1/mGluR5 is an effective treatment for physiological and behavioral alterations caused by exacerbated mRNA translation initiation. SIGNIFICANCE STATEMENT Exacerbated mRNA translation during brain development is associated with several autism spectrum disorders (ASDs). We recently demonstrated that the deletion of a negative regulator of mRNA translation initiation, the eukaryotic initiation factor 4E-binding protein 2, leads to ASD-like behaviors and increased excitatory synaptic activity. Here we demonstrated that autistic behavioral and electrophysiological phenotypes can be treated in adult mice with antagonists of group I metabotropic glutamate receptors (mGluRs), which have been previously used in other ASD models (i.e., fragile X syndrome). These findings support the use of group I mGluR antagonists as a potential therapy that extends to autism models involving exacerbated mRNA translation initiation. PMID:26245973

Inhibition of Group I Metabotropic Glutamate Receptors Reverses Autistic-Like Phenotypes Caused by Deficiency of the Translation Repressor eIF4E Binding Protein 2.

PubMed

Aguilar-Valles, Argel; Matta-Camacho, Edna; Khoutorsky, Arkady; Gkogkas, Christos; Nader, Karim; Lacaille, Jean-Claude; Sonenberg, Nahum

2015-08-05

Exacerbated mRNA translation during brain development has been linked to autism spectrum disorders (ASDs). Deletion of the eukaryotic initiation factor 4E (eIF4E)-binding protein 2 gene (Eif4ebp2), encoding the suppressor of mRNA translation initiation 4E-BP2, leads to an imbalance in excitatory-to-inhibitory neurotransmission and ASD-like behaviors. Inhibition of group I metabotropic glutamate receptors (mGluRs) mGluR1 and mGluR5 reverses the autistic phenotypes in several ASD mouse models. Importantly, these receptors control synaptic physiology via activation of mRNA translation. We investigated the potential reversal of autistic-like phenotypes in Eif4ebp2(-/-) mice by using antagonists of mGluR1 (JNJ16259685) or mGluR5 (fenobam). Augmented hippocampal mGluR-induced long-term depression (LTD; or chemically induced mGluR-LTD) in Eif4ebp2(-/-) mice was rescued by mGluR1 or mGluR5 antagonists. While rescue by mGluR5 inhibition occurs through the blockade of a protein synthesis-dependent component of LTD, normalization by mGluR1 antagonists requires the activation of protein synthesis. Synaptically induced LTD was deficient in Eif4ebp2(-/-) mice, and this deficit was not rescued by group I mGluR antagonists. Furthermore, a single dose of mGluR1 (0.3 mg/kg) or mGluR5 (3 mg/kg) antagonists in vivo reversed the deficits in social interaction and repetitive behaviors (marble burying) in Eif4ebp2(-/-) mice. Our results demonstrate that Eif4ebp2(-/-) mice serve as a relevant model to test potential therapies for ASD symptoms. In addition, we provide substantive evidence that the inhibition of mGluR1/mGluR5 is an effective treatment for physiological and behavioral alterations caused by exacerbated mRNA translation initiation. Exacerbated mRNA translation during brain development is associated with several autism spectrum disorders (ASDs). We recently demonstrated that the deletion of a negative regulator of mRNA translation initiation, the eukaryotic initiation factor 4E-binding protein 2, leads to ASD-like behaviors and increased excitatory synaptic activity. Here we demonstrated that autistic behavioral and electrophysiological phenotypes can be treated in adult mice with antagonists of group I metabotropic glutamate receptors (mGluRs), which have been previously used in other ASD models (i.e., fragile X syndrome). These findings support the use of group I mGluR antagonists as a potential therapy that extends to autism models involving exacerbated mRNA translation initiation. Copyright © 2015 the authors 0270-6474/15/3511126-08$15.00/0.

Early afterglows in wind environments revisited

NASA Astrophysics Data System (ADS)

Zou, Y. C.; Wu, X. F.; Dai, Z. G.

2005-10-01

When a cold shell sweeps up the ambient medium, a forward shock and a reverse shock will form. We analyse the reverse-forward shocks in a wind environment, including their dynamics and emission. An early afterglow is emitted from the shocked shell, e.g. an optical flash may emerge. The reverse shock behaves differently in two approximations: the relativistic and Newtonian cases, which depend on the parameters, e.g. the initial Lorentz factor of the ejecta. If the initial Lorentz factor is much less than 114E1/453Δ-1/40,12A-1/4*,-1, the early reverse shock is Newtonian. This may take place for the wider of a two-component jet, an orphan afterglow caused by a low initial Lorentz factor and so on. The synchrotron self-absorption effect is significant especially for the Newtonian reverse shock case, as the absorption frequency νa is larger than the cooling frequency νc and the minimum synchrotron frequency νm for typical parameters. For the optical to X-ray band, the flux is nearly unchanged with time during the early period, which may be a diagnostic for the low initial Lorentz factor of the ejecta in a wind environment. We also investigate the early light curves with different wind densities and compare them with those in the interstellar medium model.

Molecular Dynamics Simulation of the Allosteric Regulation of eIF4A Protein from the Open to Closed State, Induced by ATP and RNA Substrates

PubMed Central

Meng, Hongqing; Li, Chaoqun; Wang, Yan; Chen, Guangju

2014-01-01

Background Eukaryotic initiation factor 4A (eIF4A) plays a key role in the process of protein translation initiation by facilitating the melting of the 5′ proximal secondary structure of eukaryotic mRNA for ribosomal subunit attachment. It was experimentally postulated that the closed conformation of the eIF4A protein bound by the ATP and RNA substrates is coupled to RNA duplex unwinding to promote protein translation initiation, rather than an open conformation in the absence of ATP and RNA substrates. However, the allosteric process of eIF4A from the open to closed state induced by the ATP and RNA substrates are not yet fully understood. Methodology In the present work, we constructed a series of diplex and ternary models of the eIF4A protein bound by the ATP and RNA substrates to carry out molecular dynamics simulations, free energy calculations and conformation analysis and explore the allosteric properties of eIF4A. Results The results showed that the eIF4A protein completes the conformational transition from the open to closed state via two allosteric processes of ATP binding followed by RNA and vice versa. Based on cooperative allosteric network analysis, the ATP binding to the eIF4A protein mainly caused the relative rotation of two domains, while the RNA binding caused the proximity of two domains via the migration of RNA bases in the presence of ATP. The cooperative binding of ATP and RNA for the eIF4A protein plays a key role in the allosteric transition. PMID:24465900

A biochemical framework for eIF4E-dependent mRNA export and nuclear recycling of the export machinery.

PubMed

Volpon, Laurent; Culjkovic-Kraljacic, Biljana; Sohn, Hye Seon; Blanchet-Cohen, Alexis; Osborne, Michael J; Borden, Katherine L B

2017-06-01

The eukaryotic translation initiation factor eIF4E acts in the nuclear export and translation of a subset of mRNAs. Both of these functions contribute to its oncogenic potential. While the biochemical mechanisms that underlie translation are relatively well understood, the molecular basis for eIF4E's role in mRNA export remains largely unexplored. To date, over 3000 transcripts, many encoding oncoproteins, were identified as potential nuclear eIF4E export targets. These target RNAs typically contain a ∼50-nucleotide eIF4E sensitivity element (4ESE) in the 3' UTR and a 7-methylguanosine cap on the 5' end. While eIF4E associates with the cap, an unknown factor recognizes the 4ESE element. We previously identified cofactors that functionally interacted with eIF4E in mammalian cell nuclei including the leucine-rich pentatricopeptide repeat protein LRPPRC and the export receptor CRM1/XPO1. LRPPRC simultaneously interacts with both eIF4E bound to the 5' mRNA cap and the 4ESE element in the 3' UTR. In this way, LRPPRC serves as a specificity factor to recruit 4ESE-containing RNAs within the nucleus. Further, we show that CRM1 directly binds LRPPRC likely acting as the export receptor for the LRPPRC-eIF4E-4ESE RNA complex. We also found that Importin 8, the nuclear importer for cap-free eIF4E, imports RNA-free LRPPRC, potentially providing both coordinated nuclear recycling of the export machinery and an important surveillance mechanism to prevent futile export cycles. Our studies provide the first biochemical framework for the eIF4E-dependent mRNA export pathway. © 2017 Volpon et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

AMP Kinase Activation Alters Oxidant-Induced Stress Granule Assembly by Modulating Cell Signaling and Microtubule Organization.

PubMed

Mahboubi, Hicham; Koromilas, Antonis E; Stochaj, Ursula

2016-10-01

Eukaryotic cells assemble stress granules (SGs) when translation initiation is inhibited. Different cell signaling pathways regulate SG production. Particularly relevant to this process is 5'-AMP-activated protein kinase (AMPK), which functions as a stress sensor and is transiently activated by adverse physiologic conditions. Here, we dissected the role of AMPK for oxidant-induced SG formation. Our studies identified multiple steps of de novo SG assembly that are controlled by the kinase. Single-cell analyses demonstrated that pharmacological AMPK activation prior to stress exposure changed SG properties, because the granules became more abundant and smaller in size. These altered SG characteristics correlated with specific changes in cell survival, cell signaling, cytoskeletal organization, and the abundance of translation initiation factors. Specifically, AMPK activation increased stress-induced eukaryotic initiation factor (eIF) 2α phosphorylation and reduced the concentration of eIF4F complex subunits eIF4G and eIF4E. At the same time, the abundance of histone deacetylase 6 (HDAC6) was diminished. This loss of HDAC6 was accompanied by increased acetylation of α-tubulin on Lys40. Pharmacological studies further confirmed this novel AMPK-HDAC6 interplay and its importance for SG biology. Taken together, we provide mechanistic insights into the regulation of SG formation. We propose that AMPK activation stimulates oxidant-induced SG formation but limits their fusion into larger granules. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

The RNA recognition motif of eukaryotic translation initiation factor 3g (eIF3g) is required for resumption of scanning of posttermination ribosomes for reinitiation on GCN4 and together with eIF3i stimulates linear scanning.

PubMed

Cuchalová, Lucie; Kouba, Tomás; Herrmannová, Anna; Dányi, István; Chiu, Wen-Ling; Valásek, Leos

2010-10-01

Recent reports have begun unraveling the details of various roles of individual eukaryotic translation initiation factor 3 (eIF3) subunits in translation initiation. Here we describe functional characterization of two essential Saccharomyces cerevisiae eIF3 subunits, g/Tif35 and i/Tif34, previously suggested to be dispensable for formation of the 48S preinitiation complexes (PICs) in vitro. A triple-Ala substitution of conserved residues in the RRM of g/Tif35 (g/tif35-KLF) or a single-point mutation in the WD40 repeat 6 of i/Tif34 (i/tif34-Q258R) produces severe growth defects and decreases the rate of translation initiation in vivo without affecting the integrity of eIF3 and formation of the 43S PICs in vivo. Both mutations also diminish induction of GCN4 expression, which occurs upon starvation via reinitiation. Whereas g/tif35-KLF impedes resumption of scanning for downstream reinitiation by 40S ribosomes terminating at upstream open reading frame 1 (uORF1) in the GCN4 mRNA leader, i/tif34-Q258R prevents full GCN4 derepression by impairing the rate of scanning of posttermination 40S ribosomes moving downstream from uORF1. In addition, g/tif35-KLF reduces processivity of scanning through stable secondary structures, and g/Tif35 specifically interacts with Rps3 and Rps20 located near the ribosomal mRNA entry channel. Together these results implicate g/Tif35 and i/Tif34 in stimulation of linear scanning and, specifically in the case of g/Tif35, also in proper regulation of the GCN4 reinitiation mechanism.

Predictors of Post-concussion Rehabilitation Outcomes at Three-month Follow-up.

PubMed

Scott, Katie L; Strong, Carrie-Ann H; Gorter, Bethany; Donders, Jacobus

2016-01-01

To determine factors related to three-month follow-up outcomes for individuals participating in an outpatient rehabilitative treatment program for mild traumatic brain injury (TBI). Fifty participants underwent neuropsychological screening prior to treatment initiation and completed the Mayo-Portland Adaptability Inventory-4 (MPAI-4) at treatment initiation, discharge from treatment, and three months following discharge. Regression models indicated that information garnered from the neuropsychological screening prior to treatment initiation (e.g., mood symptoms and prior psychiatric history) accounted for unique variance in three-month post-discharge outcomes on several MPAI-4 subscales. Specifically, after controlling for baseline MPAI-4 ratings, higher Beck Depression Inventory-second edition (BDI-II) scores were associated with worse MPAI-4 Ability scores at three-month follow-up, and the presence of a psychiatric history was associated with worse MPAI-4 Adjustment scores at three-month follow-up. Neuropsychological screening prior to the initiation of treatment for mild TBI can help to identify patients who may be at greater risk for poorer rehabilitation outcomes, thus allowing for the implementation of specific interventions to address these risk factors.

Practice Pattern Variation in Pediatric Eosinophilic Esophagitis in the Carolinas EoE Collaborative: A Research Model in Community and Academic Practices.

PubMed

Huang, Kevin Z; Jensen, Elizabeth T; Chen, Hannah X; Landes, Lisa E; McConnell, Kristen A; Almond, M Angie; Johnston, Douglas T; Durban, Raquel; Jobe, Laura; Frost, Carrie; Donnelly, Sarah; Antonio, Brady; Safta, Anca M; Quiros, J Antonio; Markowitz, Jonathan E; Dellon, Evan S

2018-06-01

Differences in the initial management of pediatric eosinophilic esophagitis (EoE) by practice setting have not been well characterized. We aimed to characterize these differences for sites in the Carolinas EoE Collaborative (CEoEC), a multicenter network of academic and community practices. We performed a retrospective cohort study of pediatric EoE patients at five CEoEC sites: University of North Carolina (UNC) Hospital, Charlotte Asthma and Allergy Specialists, Greenville Health Systems, Wake Forest Baptist Medical Center, and the Medical University of South Carolina Hospital. Cases of EoE were defined by consensus guidelines. Data were extracted from electronic medical records. We tested for differences among sites and used a multinomial model (polytomous regression) to assess associations between treatment and site, adjusting on patient factors. We identified 464 children with EoE across the CEoEC sites. The median age was highest at Wake Forest (11.4 years), the median eosinophil count was highest at UNC (69 eos/hpf), and UNC had the most male patients (82%). UNC used topical steroids for initial treatment in 86% of cases, compared with <1% in Greenville ( P < 0.01). Greenville used dietary elimination more frequently than UNC (81% vs 2%, P < 0.01). Differences in treatment approach held after adjusting for potential baseline confounders. There was no significant association between patient factors and initial treatment approach. Significant differences in EoE patient factors and treatment approaches were identified across CEoEC sites and were not explained by patient or practice factors. This suggests that institutional or provider preferences drive initial treatment approaches, and that more data are needed to drive best practice decisions.

A novel mechanism for Bcr-Abl action: Bcr-Abl-mediated induction of the eIF4F translation initiation complex and mRNA translation.

PubMed

Prabhu, S; Saadat, D; Zhang, M; Halbur, L; Fruehauf, J P; Ong, S T

2007-02-22

The oncogenic kinase Bcr-Abl is thought to cause chronic myelogenous leukemia (CML) by altering the transcription of specific genes with growth- and survival-promoting functions. Recently, Bcr-Abl has also been shown to activate an important regulator of protein synthesis, the mammalian target of rapamycin (mTOR), which suggests that dysregulated translation may also contribute to CML pathogenesis. In this study, we found that both Bcr-Abl and the rapamycin-sensitive mTORC1 complex contribute to the phosphorylation (inactivation) of 4E-BP1, an inhibitor of the eIF4E translation initiation factor. Experiments with rapamycin and the Bcr-Abl inhibitor, imatinib mesylate, in Bcr-Abl-expressing cell lines and primary CML cells indicated that Bcr-Abl and mTORC1 induced formation of the translation initiation complex, eIF4F. This was characterized by reduced 4E-BP1 binding and increased eIF4G binding to eIF4E, two events that lead to the assembly of eIF4F. One target transcript is cyclin D3, which is regulated in Bcr-Abl-expressing cells by both Bcr-Abl and mTORC1 in a translational manner. In addition, the combination of imatinib and rapamycin was found to act synergistically against committed CML progenitors from chronic and blast phase patients. These experiments establish a novel mechanism of action for Bcr-Abl, and they provide insights into the modes of action of imatinib mesylate and rapamycin in treatment of CML. They also suggest that aberrant cap-dependent mRNA translation may be a therapeutic target in Bcr-Abl-driven malignancies.

Use of natural mRNAs in the cell-free protein-synthesizing systems of the moderate halophile Vibrio costicola.

PubMed

Choquet, C G; Kushner, D J

1990-06-01

In vitro protein synthesis was studied in extracts of the moderate halophile Vibrio costicola by using as mRNAs the endogenous mRNA of V. costicola and the RNA of the R17 bacteriophage of Escherichia coli. Protein synthesis (amino acid incorporation) was dependent on the messenger, ribosomes, soluble cytoplasmic factors, energy source, and tRNA(FMet) (in the R17 RNA system) and was inhibited by certain antibiotics. These properties indicated de novo protein synthesis. In the V. costicola system directed by R17 RNA, a protein of the same electrophoretic mobility as the major coat protein of the R17 phage was synthesized. Antibiotic action and the response to added tRNA(FMet) showed that protein synthesis in the R17 RNA system, but not in the endogenous messenger system, absolutely depended on initiation. Optimal activity of both systems was observed in 250 to 300 mM NH4+ (as glutamate). Higher salt concentrations, especially those with Cl- as anion, were generally inhibitory. The R17 RNA-directed system was more sensitive to Cl- ions than the endogenous system was. Glycine betaine stimulated both systems and partly overcame the toxic effects of Cl- ions. Both systems required Mg2+, but in lower concentrations than the polyuridylic acid-directed system previously studied. Initiation factors were removed from ribosomes by washing with 3.0 to 3.5 M NH4Cl, concentrations about three times as high as that needed to remove initiation factors from E. coli ribosomes. Washing with 4.0 M NH4Cl damaged V. costicola ribosomes, although the initiation factors still functioned. Cl- ions inhibited the attachment of initiation factors to tRNA(FMet) but had little effect on binding of initiation factors to R17 RNA.

Identification of the Drosophila eIF4A gene as a target of the DREF transcription factor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ida, Hiroyuki; Insect Biomedical Research Center, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585; Yoshida, Hideki

2007-12-10

The DNA replication-related element-binding factor (DREF) regulates cell proliferation-related gene expression in Drosophila. We have carried out a genetic screening, taking advantage of the rough eye phenotype of transgenic flies that express full-length DREF in the eye imaginal discs and identified the eukaryotic initiation factor 4A (eIF4A) gene as a dominant suppressor of the DREF-induced rough eye phenotype. The eIF4A gene was here found to carry three DRE sequences, DRE1 (- 40 to - 47), DRE2 (- 48 to - 55), and DRE3 (- 267 to - 274) in its promoter region, these all being important for the eIF4A genemore » promoter activity in cultured Drosophila Kc cells and in living flies. Knockdown of DREF in Drosophila S2 cells decreased the eIF4A mRNA level and the eIF4A gene promoter activity. Furthermore, specific binding of DREF to genomic regions containing DRE sequences was demonstrated by chromatin immunoprecipitation assays using anti-DREF antibodies. Band mobility shift assays using Kc cell nuclear extracts revealed that DREF could bind to DRE1 and DRE3 sequences in the eIF4A gene promoter in vitro, but not to the DRE2 sequence. The results suggest that the eIF4A gene is under the control of the DREF pathway and DREF is therefore involved in the regulation of protein synthesis.« less

The Expression Alteration of BC1 RNA and its Interaction with Eukaryotic Translation Initiation Factor eIF4A Post-Status Epilepticus.

PubMed

Zeng, Xiangchang; Zong, Wenjing; Gao, Qing; Chen, Siyu; Chen, Lulu; Zeng, Guirong; Huang, Weihua; Li, Zhenyu; Zeng, Chang; Xie, Yuanyuan; Li, Xiaohui; Xiao, Bo; Dongsheng-Ouyang; Hu, Kai

2018-05-17

Abnormal dendritic sprouting and synaptic remodelling are important pathological features of temporal lobe epilepsy. BC1 RNA is a translation repressor involved in the regulation of the dendritic protein synthesis and mRNA transport, which is essential for dendritic development and plasticity. The expression alteration of BC1 RNA in the pilocarpine induced epilepsy model remains unknown. It is unclear if the interactions between BC1 RNA and eukaryotic initiation factor 4A (eIF4A) exists in this model. The purpose of this study was to investigate the expression changes of BC1 RNA and its interactions with eIF4A post-status epilepticus (SE). Chloride lithium and pilocarpine were used to induce the SE rat model. Either a whole brain or hippocampus tissues were collected at different time points after SE. The expression patterns of BC1 was detected by qPCR and in situ hybridization. The levels of eIF4AI/II protein expression were analyzed via western blotting and immunohistochemistry. The BC1 RNA-eIF4AI/II interaction was determined by electrophoretic mobility shift assay (EMSA). We found that the BC1 RNA levels decreased in hippocampus 3d, 1w and 2w post-SE before the levels recovered. The eIF4AI/II began to rise 3d post-SE and reached the maximum level 1w post-SE. After 1w post-SE the levels decreased in the hippocampal CA1, CA3 and DG subregions. EMSA analysis showed that BC1 RNA specifically interacted with the eIF4AI/II. The BC1 RNA-eIF4AI/II complex reduced to the lowest level 1w post-SE. Our results suggested that BC1 has a negative regulatory correlation with eIF4AI/II, where BC1 RNA could be involved in epileptogenesis by regulating dendritic protein synthesis.

A Conserved Interaction between a C-Terminal Motif in Norovirus VPg and the HEAT-1 Domain of eIF4G Is Essential for Translation Initiation

PubMed Central

Leen, Eoin N.; Sorgeloos, Frédéric; Correia, Samantha; Chaudhry, Yasmin; Cannac, Fabien; Pastore, Chiara; Xu, Yingqi; Graham, Stephen C.; Matthews, Stephen J.; Goodfellow, Ian G.; Curry, Stephen

2016-01-01

Translation initiation is a critical early step in the replication cycle of the positive-sense, single-stranded RNA genome of noroviruses, a major cause of gastroenteritis in humans. Norovirus RNA, which has neither a 5´ m7G cap nor an internal ribosome entry site (IRES), adopts an unusual mechanism to initiate protein synthesis that relies on interactions between the VPg protein covalently attached to the 5´-end of the viral RNA and eukaryotic initiation factors (eIFs) in the host cell. For murine norovirus (MNV) we previously showed that VPg binds to the middle fragment of eIF4G (4GM; residues 652–1132). Here we have used pull-down assays, fluorescence anisotropy, and isothermal titration calorimetry (ITC) to demonstrate that a stretch of ~20 amino acids at the C terminus of MNV VPg mediates direct and specific binding to the HEAT-1 domain within the 4GM fragment of eIF4G. Our analysis further reveals that the MNV C terminus binds to eIF4G HEAT-1 via a motif that is conserved in all known noroviruses. Fine mutagenic mapping suggests that the MNV VPg C terminus may interact with eIF4G in a helical conformation. NMR spectroscopy was used to define the VPg binding site on eIF4G HEAT-1, which was confirmed by mutagenesis and binding assays. We have found that this site is non-overlapping with the binding site for eIF4A on eIF4G HEAT-1 by demonstrating that norovirus VPg can form ternary VPg-eIF4G-eIF4A complexes. The functional significance of the VPg-eIF4G interaction was shown by the ability of fusion proteins containing the C-terminal peptide of MNV VPg to inhibit in vitro translation of norovirus RNA but not cap- or IRES-dependent translation. These observations define important structural details of a functional interaction between norovirus VPg and eIF4G and reveal a binding interface that might be exploited as a target for antiviral therapy. PMID:26734730

Characterization of a novel RNA-binding region of eIF4GI critical for ribosomal scanning

PubMed Central

Prévôt, Déborah; Décimo, Didier; Herbreteau, Cécile H.; Roux, Florence; Garin, Jérôme; Darlix, Jean-Luc; Ohlmann, Théophile

2003-01-01

The eukaryotic translation initiation factor eIF4GI binds several proteins and acts as a scaffold to promote preinitiation complex formation on the mRNA molecule (48S). Following mRNA attachment this complex scans along the messenger in a 5′ to 3′ direction until it locates and recognizes the initiation start codon. By using a combination of retroviral and picornaviral proteases (HIV-2 and L respectively) in the reticulocyte lysate system, we have characterized a 40 amino acid (aa) region of eIF4GI (aa 642–681) that exhibits general RNA-binding properties. Removal of this domain by proteolytic processing followed by translational assays showed virtually no inhibition of internal ribosome entry on the encephalomyocarditis virus, but resulted in drastic impairment of ribosome scanning as demonstrated by studying poliovirus and foot-and-mouth disease virus translation. Based on these findings, we propose that this 40 aa motif of eIF4GI is critical for ribosome scanning. PMID:12682023

eIF4A RNA Helicase Associates with Cyclin-Dependent Protein Kinase A in Proliferating Cells and Is Modulated by Phosphorylation1[OPEN

PubMed Central

Bush, Maxwell S.; Pierrat, Olivier; Nibau, Candida; Mikitova, Veronika; Zheng, Tao; Corke, Fiona M. K.; Mayberry, Laura K.; Browning, Karen S.

2016-01-01

Eukaryotic initiation factor 4A (eIF4A) is a highly conserved RNA-stimulated ATPase and helicase involved in the initiation of messenger RNA translation. Previously, we found that eIF4A interacts with cyclin-dependent kinase A (CDKA), the plant ortholog of mammalian CDK1. Here, we show that this interaction occurs only in proliferating cells where the two proteins coassociate with 5′-cap-binding protein complexes, eIF4F or the plant-specific eIFiso4F. CDKA phosphorylates eIF4A on a conserved threonine residue (threonine-164) within the RNA-binding motif 1b TPGR. In vivo, a phospho-null (APGR) variant of the Arabidopsis (Arabidopsis thaliana) eIF4A1 protein retains the ability to functionally complement a mutant (eif4a1) plant line lacking eIF4A1, whereas a phosphomimetic (EPGR) variant fails to complement. The phospho-null variant (APGR) rescues the slow growth rate of roots and rosettes, together with the ovule-abortion and late-flowering phenotypes. In vitro, wild-type recombinant eIF4A1 and its phospho-null variant both support translation in cell-free wheat germ extracts dependent upon eIF4A, but the phosphomimetic variant does not support translation and also was deficient in ATP hydrolysis and helicase activity. These observations suggest a mechanism whereby CDK phosphorylation has the potential to down-regulate eIF4A activity and thereby affect translation. PMID:27388680

Attitudes toward E-Cigarettes, Reasons for Initiating E-Cigarette Use, and Changes in Smoking Behavior after Initiation: A Pilot Longitudinal Study of Regular Cigarette Smokers.

PubMed

Berg, Carla J; Barr, Dana Boyd; Stratton, Erin; Escoffery, Cam; Kegler, Michelle

2014-10-01

We examined 1) changes in smoking and vaping behavior and associated cotinine levels and health status among regular smokers who were first-time e-cigarette purchasers and 2) attitudes, intentions, and restrictions regarding e-cigarettes. We conducted a pilot longitudinal study with assessments of the aforementioned factors and salivary cotinine at weeks 0, 4, and 8. Eligibility criteria included being ≥18 years old, smoking ≥25 of the last 30 days, smoking ≥5 cigarettes per day (cpd), smoking regularly ≥1 year, and not having started using e-cigarettes. Of 72 individuals screened, 40 consented, 36 completed the baseline survey, and 83.3% and 72.2% were retained at weeks 4 and 8, respectively. Participants reduced cigarette consumption from baseline to week 4 and 8 (p's < 0.001); 23.1% reported no cigarette use in the past month at week 8. There was no significant decrease in cotinine from baseline to week 4 or 8 (p's = ns). At week 8, the majority reported improved health (65.4%), reduced smoker's cough (57.7%), and improved sense of smell (53.8%) and taste (50.0%). The majority believed that e-cigarettes versus regular cigarettes have fewer health risks (97.2%) and that e-cigarettes have been shown to help smokers quit (80.6%) and reduce cigarette consumption (97.2%). In addition, the majority intended to use e-cigarettes as a complete replacement for regular cigarettes (69.4%) and reported no restriction on e-cigarette use in the home (63.9%) or car (80.6%). Future research is needed to document the long-term impact on smoking behavior and health among cigarette smokers who initiate use of e-cigarettes.

Influenza A virus-induced degradation of eukaryotic translation initiation factor 4B contributes to viral replication by suppressing IFITM3 protein expression.

PubMed

Wang, Song; Chi, Xiaojuan; Wei, Haitao; Chen, Yuhai; Chen, Zhilong; Huang, Shile; Chen, Ji-Long

2014-08-01

Although alteration in host cellular translation machinery occurs in virus-infected cells, the role of such alteration and the precise pathogenic processes are not well understood. Influenza A virus (IAV) infection shuts off host cell gene expression at transcriptional and translational levels. Here, we found that the protein level of eukaryotic translation initiation factor 4B (eIF4B), an integral component of the translation initiation apparatus, was dramatically reduced in A549 cells as well as in the lung, spleen, and thymus of mice infected with IAV. The decrease in eIF4B level was attributed to lysosomal degradation of eIF4B, which was induced by viral NS1 protein. Silencing eIF4B expression in A549 cells significantly promoted IAV replication, and conversely, overexpression of eIF4B markedly inhibited the viral replication. Importantly, we observed that eIF4B knockdown transgenic mice were more susceptible to IAV infection, exhibiting faster weight loss, shorter survival time, and more-severe organ damage. Furthermore, we demonstrated that eIF4B regulated the expression of interferon-induced transmembrane protein 3 (IFITM3), a critical protein involved in immune defense against a variety of RNA viruses, including influenza virus. Taken together, our findings reveal that eIF4B plays an important role in host defense against IAV infection at least by regulating the expression of IFITM3, which restricts viral entry and thereby blocks early stages of viral production. These data also indicate that influenza virus has evolved a strategy to overcome host innate immunity by downregulating eIF4B protein. Influenza A virus (IAV) infection stimulates the host innate immune system, in part, by inducing interferons (IFNs). Secreted IFNs activate the Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway, leading to elevated transcription of a large group of IFN-stimulated genes that have antiviral function. To circumvent the host innate immune response, influenza virus has evolved multiple strategies for suppressing the production of IFNs. Here, we show that IAV infection induces lysosomal degradation of eIF4B protein; and eIF4B inhibits IAV replication by upregulating expression of interferon-induced transmembrane protein 3 (IFITM3), a key protein that protects the host from virus infection. Our finding illustrates a critical role of eIF4B in the host innate immune response and provides novel insights into the complex mechanisms by which influenza virus interacts with its host. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Reducing eIF4E-eIF4G interactions restores the balance between protein synthesis and actin dynamics in fragile X syndrome model mice.

PubMed

Santini, Emanuela; Huynh, Thu N; Longo, Francesco; Koo, So Yeon; Mojica, Edward; D'Andrea, Laura; Bagni, Claudia; Klann, Eric

2017-11-07

Fragile X syndrome (FXS) is the most common form of inherited intellectual disability and autism spectrum disorder. FXS is caused by silencing of the FMR1 gene, which encodes fragile X mental retardation protein (FMRP), an mRNA-binding protein that represses the translation of its target mRNAs. One mechanism by which FMRP represses translation is through its association with cytoplasmic FMRP-interacting protein 1 (CYFIP1), which subsequently sequesters and inhibits eukaryotic initiation factor 4E (eIF4E). CYFIP1 shuttles between the FMRP-eIF4E complex and the Rac1-Wave regulatory complex, thereby connecting translational regulation to actin dynamics and dendritic spine morphology, which are dysregulated in FXS model mice that lack FMRP. Treating FXS mice with 4EGI-1, which blocks interactions between eIF4E and eIF4G, a critical interaction partner for translational initiation, reversed defects in hippocampus-dependent memory and spine morphology. We also found that 4EGI-1 normalized the phenotypes of enhanced metabotropic glutamate receptor (mGluR)-mediated long-term depression (LTD), enhanced Rac1-p21-activated kinase (PAK)-cofilin signaling, altered actin dynamics, and dysregulated CYFIP1/eIF4E and CYFIP1/Rac1 interactions in FXS mice. Our findings are consistent with the idea that an imbalance in protein synthesis and actin dynamics contributes to pathophysiology in FXS mice, and suggest that targeting eIF4E may be a strategy for treating FXS. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Discovery of selective ATP-competitive eIF4A3 inhibitors.

PubMed

Ito, Masahiro; Iwatani, Misa; Kamada, Yusuke; Sogabe, Satoshi; Nakao, Shoichi; Tanaka, Toshio; Kawamoto, Tomohiro; Aparicio, Samuel; Nakanishi, Atsushi; Imaeda, Yasuhiro

2017-04-01

Eukaryotic initiation factor 4A3 (eIF4A3), an ATP-dependent RNA helicase, is a core component of exon junction complex (EJC). EJC has a variety of roles in RNA metabolism such as translation, surveillance, and localization of spliced RNA. It is worthwhile to identify selective eIF4A3 inhibitors with a view to investigating the functions of eIF4A3 and EJC further to clarify the roles of the ATPase and helicase activities in cells. Our chemical optimization of hit compound 2 culminated in the discovery of ATP-competitive eIF4A3 inhibitor 18 with submicromolar ATPase inhibitory activity and excellent selectivity over other helicases. Hence, compound 18 could be a valuable chemical probe to elucidate the detailed functions of eIF4A3 and EJC. Copyright © 2017 Elsevier Ltd. All rights reserved.

Development and psychometric evaluation of the Personal Growth Initiative Scale-II.

PubMed

Robitschek, Christine; Ashton, Matthew W; Spering, Cynthia C; Geiger, Nathaniel; Byers, Danielle; Schotts, G Christian; Thoen, Megan A

2012-04-01

The original Personal Growth Initiative Scale (PGIS; Robitschek, 1998) was unidimensional, despite theory identifying multiple components (e.g., cognition and behavior) of personal growth initiative (PGI). The present research developed a multidimensional measure of the complex process of PGI, while retaining the brief and psychometrically sound properties of the original scale. Study 1 focused on scale development, including theoretical derivation of items, assessing factor structure, reducing number of items, and refining the scale length using samples of college students. Study 2 consisted of confirmatory factor analysis with 3 independent samples of college students and community members. Lastly, Study 3 assessed test-retest reliability over 1-, 2-, 4-, and 6-week periods and tests of concurrent and discriminant validity using samples of college students. The final measure, the Personal Growth Initiative Scale-II (PGIS-II), includes 4 subscales: Readiness for Change, Planfulness, Using Resources, and Intentional Behavior. These studies provide exploratory and confirmatory evidence for the 4-factor structure, strong internal consistency for the subscales and overall score across samples, acceptable temporal stability at all assessed intervals, and concurrent and discriminant validity of the PGIS-II. Future directions for research and clinical practice are discussed.

Gene expression profiling combined with bioinformatics analysis identify biomarkers for Parkinson disease.

PubMed

Diao, Hongyu; Li, Xinxing; Hu, Sheng; Liu, Yunhui

2012-01-01

Parkinson disease (PD) progresses relentlessly and affects approximately 4% of the population aged over 80 years old. It is difficult to diagnose in its early stages. The purpose of our study is to identify molecular biomarkers for PD initiation using a computational bioinformatics analysis of gene expression. We downloaded the gene expression profile of PD from Gene Expression Omnibus and identified differentially coexpressed genes (DCGs) and dysfunctional pathways in PD patients compared to controls. Besides, we built a regulatory network by mapping the DCGs to known regulatory data between transcription factors (TFs) and target genes and calculated the regulatory impact factor of each transcription factor. As the results, a total of 1004 genes associated with PD initiation were identified. Pathway enrichment of these genes suggests that biological processes of protein turnover were impaired in PD. In the regulatory network, HLF, E2F1 and STAT4 were found have altered expression levels in PD patients. The expression levels of other transcription factors, NKX3-1, TAL1, RFX1 and EGR3, were not found altered. However, they regulated differentially expressed genes. In conclusion, we suggest that HLF, E2F1 and STAT4 may be used as molecular biomarkers for PD; however, more work is needed to validate our result.

Gene Expression Profiling Combined with Bioinformatics Analysis Identify Biomarkers for Parkinson Disease

PubMed Central

Diao, Hongyu; Li, Xinxing; Hu, Sheng; Liu, Yunhui

2012-01-01

Parkinson disease (PD) progresses relentlessly and affects approximately 4% of the population aged over 80 years old. It is difficult to diagnose in its early stages. The purpose of our study is to identify molecular biomarkers for PD initiation using a computational bioinformatics analysis of gene expression. We downloaded the gene expression profile of PD from Gene Expression Omnibus and identified differentially coexpressed genes (DCGs) and dysfunctional pathways in PD patients compared to controls. Besides, we built a regulatory network by mapping the DCGs to known regulatory data between transcription factors (TFs) and target genes and calculated the regulatory impact factor of each transcription factor. As the results, a total of 1004 genes associated with PD initiation were identified. Pathway enrichment of these genes suggests that biological processes of protein turnover were impaired in PD. In the regulatory network, HLF, E2F1 and STAT4 were found have altered expression levels in PD patients. The expression levels of other transcription factors, NKX3-1, TAL1, RFX1 and EGR3, were not found altered. However, they regulated differentially expressed genes. In conclusion, we suggest that HLF, E2F1 and STAT4 may be used as molecular biomarkers for PD; however, more work is needed to validate our result. PMID:23284986

Acute Fasting Regulates Retrograde Synaptic Enhancement through a 4E-BP-Dependent Mechanism.

PubMed

Kauwe, Grant; Tsurudome, Kazuya; Penney, Jay; Mori, Megumi; Gray, Lindsay; Calderon, Mario R; Elazouzzi, Fatima; Chicoine, Nicole; Sonenberg, Nahum; Haghighi, A Pejmun

2016-12-21

While beneficial effects of fasting on organismal function and health are well appreciated, we know little about the molecular details of how fasting influences synaptic function and plasticity. Our genetic and electrophysiological experiments demonstrate that acute fasting blocks retrograde synaptic enhancement that is normally triggered as a result of reduction in postsynaptic receptor function at the Drosophila larval neuromuscular junction (NMJ). This negative regulation critically depends on transcriptional enhancement of eukaryotic initiation factor 4E binding protein (4E-BP) under the control of the transcription factor Forkhead box O (Foxo). Furthermore, our findings indicate that postsynaptic 4E-BP exerts a constitutive negative input, which is counteracted by a positive regulatory input from the Target of Rapamycin (TOR). This combinatorial retrograde signaling plays a key role in regulating synaptic strength. Our results provide a mechanistic insight into how cellular stress and nutritional scarcity could acutely influence synaptic homeostasis and functional stability in neural circuits. Copyright © 2016 Elsevier Inc. All rights reserved.

Brd4 modulates the innate immune response through Mnk2-eIF4E pathway-dependent translational control of IκBα.

PubMed

Bao, Yan; Wu, Xuewei; Chen, Jinjing; Hu, Xiangming; Zeng, Fuxing; Cheng, Jianjun; Jin, Hong; Lin, Xin; Chen, Lin-Feng

2017-05-16

Bromodomain-containing factor Brd4 has emerged as an important transcriptional regulator of NF-κB-dependent inflammatory gene expression. However, the in vivo physiological function of Brd4 in the inflammatory response remains poorly defined. We now demonstrate that mice deficient for Brd4 in myeloid-lineage cells are resistant to LPS-induced sepsis but are more susceptible to bacterial infection. Gene-expression microarray analysis of bone marrow-derived macrophages (BMDMs) reveals that deletion of Brd4 decreases the expression of a significant amount of LPS-induced inflammatory genes while reversing the expression of a small subset of LPS-suppressed genes, including MAP kinase-interacting serine/threonine-protein kinase 2 ( Mknk2 ). Brd4 -deficient BMDMs display enhanced Mnk2 expression and the corresponding eukaryotic translation initiation factor 4E (eIF4E) activation after LPS stimulation, leading to an increased translation of IκBα mRNA in polysomes. The enhanced newly synthesized IκBα reduced the binding of NF-κB to the promoters of inflammatory genes, resulting in reduced inflammatory gene expression and cytokine production. By modulating the translation of IκBα via the Mnk2-eIF4E pathway, Brd4 provides an additional layer of control for NF-κB-dependent inflammatory gene expression and inflammatory response.

eIF2β is critical for eIF5-mediated GDP-dissociation inhibitor activity and translational control

PubMed Central

Jennings, Martin D.; Kershaw, Christopher J.; White, Christopher; Hoyle, Danielle; Richardson, Jonathan P.; Costello, Joseph L.; Donaldson, Ian J.; Zhou, Yu; Pavitt, Graham D.

2016-01-01

In protein synthesis translation factor eIF2 binds initiator tRNA to ribosomes and facilitates start codon selection. eIF2 GDP/GTP status is regulated by eIF5 (GAP and GDI functions) and eIF2B (GEF and GDF activities), while eIF2α phosphorylation in response to diverse signals is a major point of translational control. Here we characterize a growth suppressor mutation in eIF2β that prevents eIF5 GDI and alters cellular responses to reduced eIF2B activity, including control of GCN4 translation. By monitoring the binding of fluorescent nucleotides and initiator tRNA to purified eIF2 we show that the eIF2β mutation does not affect intrinsic eIF2 affinities for these ligands, neither does it interfere with eIF2 binding to 43S pre-initiation complex components. Instead we show that the eIF2β mutation prevents eIF5 GDI stabilizing nucleotide binding to eIF2, thereby altering the off-rate of GDP from eIF2•GDP/eIF5 complexes. This enables cells to grow with reduced eIF2B GEF activity but impairs activation of GCN4 targets in response to amino acid starvation. These findings provide support for the importance of eIF5 GDI activity in vivo and demonstrate that eIF2β acts in concert with eIF5 to prevent premature release of GDP from eIF2γ and thereby ensure tight control of protein synthesis initiation. PMID:27458202

eIF2β is critical for eIF5-mediated GDP-dissociation inhibitor activity and translational control.

PubMed

Jennings, Martin D; Kershaw, Christopher J; White, Christopher; Hoyle, Danielle; Richardson, Jonathan P; Costello, Joseph L; Donaldson, Ian J; Zhou, Yu; Pavitt, Graham D

2016-11-16

In protein synthesis translation factor eIF2 binds initiator tRNA to ribosomes and facilitates start codon selection. eIF2 GDP/GTP status is regulated by eIF5 (GAP and GDI functions) and eIF2B (GEF and GDF activities), while eIF2α phosphorylation in response to diverse signals is a major point of translational control. Here we characterize a growth suppressor mutation in eIF2β that prevents eIF5 GDI and alters cellular responses to reduced eIF2B activity, including control of GCN4 translation. By monitoring the binding of fluorescent nucleotides and initiator tRNA to purified eIF2 we show that the eIF2β mutation does not affect intrinsic eIF2 affinities for these ligands, neither does it interfere with eIF2 binding to 43S pre-initiation complex components. Instead we show that the eIF2β mutation prevents eIF5 GDI stabilizing nucleotide binding to eIF2, thereby altering the off-rate of GDP from eIF2•GDP/eIF5 complexes. This enables cells to grow with reduced eIF2B GEF activity but impairs activation of GCN4 targets in response to amino acid starvation. These findings provide support for the importance of eIF5 GDI activity in vivo and demonstrate that eIF2β acts in concert with eIF5 to prevent premature release of GDP from eIF2γ and thereby ensure tight control of protein synthesis initiation. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Architecture of human translation initiation factor 3

PubMed Central

Querol-Audi, Jordi; Sun, Chaomin; Vogan, Jacob M.; Smith, Duane; Gu, Yu; Cate, Jamie; Nogales, Eva

2013-01-01

SUMMARY Eukaryotic translation initiation factor 3 (eIF3) plays a central role in protein synthesis by organizing the formation of the 43S preinitiation complex. Using genetic tag visualization by electron microscopy, we reveal the molecular organization of ten human eIF3 subunits, including an octameric core. The structure of eIF3 bears a close resemblance to that of the proteasome lid, with a conserved spatial organization of eight core subunits containing PCI and MPN domains that coordinate functional interactions in both complexes. We further show that eIF3 subunits a and c interact with initiation factors eIF1 and eIF1A, which control the stringency of start codon selection. Finally, we find that subunit j, which modulates messenger RNA interactions with the small ribosomal subunit, makes multiple independent interactions with the eIF3 octameric core. These results highlight the conserved architecture of eIF3 and how it scaffolds key factors that control translation initiation in higher eukaryotes, including humans. PMID:23623729

Impact of medical and nonmedical factors on physician decision making for HIV/AIDS antiretroviral treatment.

PubMed

Bogart, L M; Kelly, J A; Catz, S L; Sosman, J M

2000-04-15

To examine influences of medical factors (e.g., viral load) and nonmedical factors (e.g., patient characteristics) on treatment decisions for highly active antiretroviral therapy (HAART), we sent a survey to a random sample of 995 infectious disease physicians who treat patients with HIV/AIDS in the United States in August, 1998. The response rate was 53%. Respondents were asked to report their current practices with respect to antiretroviral treatment and the extent to which each of three medical and 17 nonmedical factors would influence them for or against prescribing HAART to a hypothetical HIV-positive patient. Most reported initiating HAART with findings of low CD4+ cell counts and high viral loads, and weighing CD4+ cell counts, viral load, and opportunistic infection heavily in their decisions to prescribe HAART. Patients' prior history of poor adherence was weighed very much against initiating HAART. Patient homelessness, heavy alcohol use, injection drug use, and prior psychiatric hospitalization were cited by most physicians as weighing against HAART initiation. Thus, most physicians in this sample follow guidelines for the use of HAART, and nonmedical factors related to patients' life situations are weighed as heavily as disease severity in treatment decisions. As HIV increasingly becomes a disease associated with economic disadvantage and other social health problems, it will be essential to develop interventions and care support systems to enable patients experiencing these problems to benefit from HIV treatment advances.

Translation of 5′ leaders is pervasive in genes resistant to eIF2 repression

PubMed Central

Fahey, Ciara; Kenny, Elaine M; Terenin, Ilya M; Dmitriev, Sergey E; Cormican, Paul; Morris, Derek W; Shatsky, Ivan N; Baranov, Pavel V

2015-01-01

Eukaryotic cells rapidly reduce protein synthesis in response to various stress conditions. This can be achieved by the phosphorylation-mediated inactivation of a key translation initiation factor, eukaryotic initiation factor 2 (eIF2). However, the persistent translation of certain mRNAs is required for deployment of an adequate stress response. We carried out ribosome profiling of cultured human cells under conditions of severe stress induced with sodium arsenite. Although this led to a 5.4-fold general translational repression, the protein coding open reading frames (ORFs) of certain individual mRNAs exhibited resistance to the inhibition. Nearly all resistant transcripts possess at least one efficiently translated upstream open reading frame (uORF) that represses translation of the main coding ORF under normal conditions. Site-specific mutagenesis of two identified stress resistant mRNAs (PPP1R15B and IFRD1) demonstrated that a single uORF is sufficient for eIF2-mediated translation control in both cases. Phylogenetic analysis suggests that at least two regulatory uORFs (namely, in SLC35A4 and MIEF1) encode functional protein products. DOI: http://dx.doi.org/10.7554/eLife.03971.001 PMID:25621764

Dynamic NF-κB and E2F interactions control the priority and timing of inflammatory signalling and cell proliferation

PubMed Central

Ankers, John M; Awais, Raheela; Jones, Nicholas A; Boyd, James; Ryan, Sheila; Adamson, Antony D; Harper, Claire V; Bridge, Lloyd; Spiller, David G; Jackson, Dean A; Paszek, Pawel; Sée, Violaine; White, Michael RH

2016-01-01

Dynamic cellular systems reprogram gene expression to ensure appropriate cellular fate responses to specific extracellular cues. Here we demonstrate that the dynamics of Nuclear Factor kappa B (NF-κB) signalling and the cell cycle are prioritised differently depending on the timing of an inflammatory signal. Using iterative experimental and computational analyses, we show physical and functional interactions between NF-κB and the E2 Factor 1 (E2F-1) and E2 Factor 4 (E2F-4) cell cycle regulators. These interactions modulate the NF-κB response. In S-phase, the NF-κB response was delayed or repressed, while cell cycle progression was unimpeded. By contrast, activation of NF-κB at the G1/S boundary resulted in a longer cell cycle and more synchronous initial NF-κB responses between cells. These data identify new mechanisms by which the cellular response to stress is differentially controlled at different stages of the cell cycle. DOI: http://dx.doi.org/10.7554/eLife.10473.001 PMID:27185527

The Eukaryotic Translation Initiation Factor 4E Controls Lettuce Susceptibility to the Potyvirus Lettuce mosaic virus1

PubMed Central

Nicaise, Valérie; German-Retana, Sylvie; Sanjuán, Raquel; Dubrana, Marie-Pierre; Mazier, Marianne; Maisonneuve, Brigitte; Candresse, Thierry; Caranta, Carole; LeGall, Olivier

2003-01-01

The eIF4E and eIF(iso)4E cDNAs from several genotypes of lettuce (Lactuca sativa) that are susceptible, tolerant, or resistant to infection by Lettuce mosaic virus (LMV; genus Potyvirus) were cloned and sequenced. Although Ls-eIF(iso)4E was monomorphic in sequence, three types of Ls-eIF4E differed by point sequence variations, and a short in-frame deletion in one of them. The amino acid variations specific to Ls-eIF4E1 and Ls-eIF4E2 were predicted to be located near the cap recognition pocket in a homology-based tridimensional protein model. In 19 lettuce genotypes, including two near-isogenic pairs, there was a strict correlation between these three allelic types and the presence or absence of the recessive LMV resistance genes mo11 and mo12. Ls-eIF4E1 and mo11 cosegregated in the progeny of two separate crosses between susceptible genotypes and an mo11 genotype. Finally, transient ectopic expression of Ls-eIF4E restored systemic accumulation of a green fluorescent protein-tagged LMV in LMV-resistant mo12 plants and a recombinant LMV expressing Ls-eIF4E° from its genome, but not Ls-eIF4E1 or Ls-eIF(iso)4E, accumulated and produced symptoms in mo11 or mo12 genotypes. Therefore, sequence correlation, tight genetic linkage, and functional complementation strongly suggest that eIF4E plays a role in the LMV cycle in lettuce and that mo11 and mo12 are alleles coding for forms of eIF4E unable or less effective to fulfill this role. More generally, the isoforms of eIF4E appear to be host factors involved in the cycle of potyviruses in plants, probably through a general mechanism yet to be clarified. PMID:12857809

Inhibition of Mitogen-activated Protein Kinase (MAPK)-interacting Kinase (MNK) Preferentially Affects Translation of mRNAs Containing Both a 5'-Terminal Cap and Hairpin.

PubMed

Korneeva, Nadejda L; Song, Anren; Gram, Hermann; Edens, Mary Ann; Rhoads, Robert E

2016-02-12

The MAPK-interacting kinases 1 and 2 (MNK1 and MNK2) are activated by extracellular signal-regulated kinases 1 and 2 (ERK1/2) or p38 in response to cellular stress and extracellular stimuli that include growth factors, cytokines, and hormones. Modulation of MNK activity affects translation of mRNAs involved in the cell cycle, cancer progression, and cell survival. However, the mechanism by which MNK selectively affects translation of these mRNAs is not understood. MNK binds eukaryotic translation initiation factor 4G (eIF4G) and phosphorylates the cap-binding protein eIF4E. Using a cell-free translation system from rabbit reticulocytes programmed with mRNAs containing different 5'-ends, we show that an MNK inhibitor, CGP57380, affects translation of only those mRNAs that contain both a cap and a hairpin in the 5'-UTR. Similarly, a C-terminal fragment of human eIF4G-1, eIF4G(1357-1600), which prevents binding of MNK to intact eIF4G, reduces eIF4E phosphorylation and inhibits translation of only capped and hairpin-containing mRNAs. Analysis of proteins bound to m(7)GTP-Sepharose reveals that both CGP and eIF4G(1357-1600) decrease binding of eIF4E to eIF4G. These data suggest that MNK stimulates translation only of mRNAs containing both a cap and 5'-terminal RNA duplex via eIF4E phosphorylation, thereby enhancing the coupled cap-binding and RNA-unwinding activities of eIF4F. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Reducing eIF4E-eIF4G Interactions Restores the Balance Between Protein Synthesis and Actin Dynamics in Fragile X Syndrome Model Mice*

PubMed Central

Santini, Emanuela; Huynh, Thu N.; Longo, Francesco; Koo, So Yeon; Mojica, Edward; D’Andrea, Laura; Bagni, Claudia; Klann, Eric

2018-01-01

Fragile X syndrome (FXS) is the most common form of inherited intellectual disability and autism spectrum disorder. FXS is caused by silencing of the FMR1 gene, which encodes fragile X mental retardation protein (FMRP), an mRNA-binding protein that represses the translation of its target mRNAs. One mechanism by which FMRP represses translation is through its association with cytoplasmic FMRP-interacting protein 1 (CYFIP1), which binds to and sequesters eukaryotic initiation factor 4E (eIF4E). CYFIP1 shuttles between the FMRP–eIF4E complex and the Rac1–Wave regulatory complex, thereby connecting translation regulation to actin dynamics and dendritic spine morphology, which are dysregulated in FXS model mice that lack FMRP. Treating FXS mice with 4EGI-1, which blocks interactions between eIF4E and eukaryotic factor 4G (eIF4G), a critical interacting partner for protein synthesis, reversed defects in hippocampus-dependent memory and spine morphology. We also found that 4EGI-1 normalized the phenotypes of enhanced metabotropic glutamate receptor (mGluR)-mediated long-term depression (LTD), upregulated Rac1–p21-activated kinase (PAK)–cofilin signaling, altered actin dynamics, and dysregulated CYFIP1/eIF4E and CYFIP1/Rac1 interactions in FXS mice. Our findings are consistent with the idea that an imbalance of protein synthesis and actin dynamics contributes to pathophysiology in FXS mice, and suggest that targeting eIF4E may be a strategy for treating FXS. PMID:29114037

Differential Phosphorylation of Plant Translation Initiation Factors by Arabidopsis thaliana CK2 Holoenzymes*

PubMed Central

Dennis, Michael D.; Browning, Karen S.

2009-01-01

A previously described wheat germ protein kinase (Yan, T. F., and Tao, M. (1982) J. Biol. Chem. 257, 7037–7043) was identified unambiguously as CK2 using mass spectrometry. CK2 is a ubiquitous eukaryotic protein kinase that phosphorylates a wide range of substrates. In previous studies, this wheat germ kinase was shown to phosphorylate eIF2α, eIF3c, and three large subunit (60 S) ribosomal proteins (Browning, K. S., Yan, T. F., Lauer, S. J., Aquino, L. A., Tao, M., and Ravel, J. M. (1985) Plant Physiol. 77, 370–373). To further characterize the role of CK2 in the regulation of translation initiation, Arabidopsis thaliana catalytic (α1 and α2) and regulatory (β1, β2, β3, and β4) subunits of CK2 were cloned and expressed in Escherichia coli. Recombinant A. thaliana CK2β subunits spontaneously dimerize and assemble into holoenzymes in the presence of either CK2α1 or CK2α2 and exhibit autophosphorylation. The purified CK2 subunits were used to characterize the properties of the individual subunits and their ability to phosphorylate various plant protein substrates. CK2 was shown to phosphorylate eIF2α, eIF2β, eIF3c, eIF4B, eIF5, and histone deacetylase 2B but did not phosphorylate eIF1, eIF1A, eIF4A, eIF4E, eIF4G, eIFiso4E, or eIFiso4G. Differential phosphorylation was exhibited by CK2 in the presence of various regulatory β-subunits. Analysis of A. thaliana mutants either lacking or overexpressing CK2 subunits showed that the amount of eIF2β protein present in extracts was affected, which suggests that CK2 phosphorylation may play a role in eIF2β stability. These results provide evidence for a potential mechanism through which the expression and/or subcellular distribution of CK2 β-subunits could participate in the regulation of the initiation of translation and other physiological processes in plants. PMID:19509278

Skeletal muscle-specific eukaryotic translation initiation factor 2α phosphorylation controls amino acid metabolism and fibroblast growth factor 21-mediated non-cell-autonomous energy metabolism.

PubMed

Miyake, Masato; Nomura, Akitoshi; Ogura, Atsushi; Takehana, Kenji; Kitahara, Yoshihiro; Takahara, Kazuna; Tsugawa, Kazue; Miyamoto, Chinobu; Miura, Naoko; Sato, Ryosuke; Kurahashi, Kiyoe; Harding, Heather P; Oyadomari, Miho; Ron, David; Oyadomari, Seiichi

2016-02-01

The eukaryotic translation initiation factor 2α (eIF2α) phosphorylation-dependent integrated stress response (ISR), a component of the unfolded protein response, has long been known to regulate intermediary metabolism, but the details are poorly worked out. We report that profiling of mRNAs of transgenic mice harboring a ligand-activated skeletal muscle-specific derivative of the eIF2α protein kinase R-like ER kinase revealed the expected up-regulation of genes involved in amino acid biosynthesis and transport but also uncovered the induced expression and secretion of a myokine, fibroblast growth factor 21 (FGF21), that stimulates energy consumption and prevents obesity. The link between the ISR and FGF21 expression was further reinforced by the identification of a small-molecule ISR activator that promoted Fgf21 expression in cell-based screens and by implication of the ISR-inducible activating transcription factor 4 in the process. Our findings establish that eIF2α phosphorylation regulates not only cell-autonomous proteostasis and amino acid metabolism, but also affects non-cell-autonomous metabolic regulation by induced expression of a potent myokine. © FASEB.

Drosophila Longevity Assurance Conferred by Reduced Insulin Receptor Substrate Chico Partially Requires d4eBP.

PubMed

Bai, Hua; Post, Stephanie; Kang, Ping; Tatar, Marc

2015-01-01

Mutations of the insulin/IGF signaling (IIS) pathway extend Drosophila lifespan. Based on genetic epistasis analyses, this longevity assurance is attributed to downstream effects of the FOXO transcription factor. However, as reported FOXO accounts for only a portion of the observed longevity benefit, suggesting there are additional outputs of IIS to mediate aging. One candidate is target of rapamycin complex 1 (TORC1). Reduced TORC1 activity is reported to slow aging, whereas reduced IIS is reported to repress TORC1 activity. The eukaryotic translation initiation factor 4E binding protein (4E-BP) is repressed by TORC1, and activated 4E-BP is reported to increase Drosophila lifespan. Here we use genetic epistasis analyses to test whether longevity assurance mutants of chico, the Drosophila insulin receptor substrate homolog, require Drosophila d4eBP to slow aging. In chico heterozygotes, which are robustly long-lived, d4eBP is required but not sufficient to slow aging. Remarkably, d4eBP is not required or sufficient for chico homozygotes to extend longevity. Likewise, chico heterozygote females partially require d4eBP to preserve age-dependent locomotion, and both chico genotypes require d4eBP to improve stress-resistance. Reproduction and most measures of growth affected by either chico genotype are always independent of d4eBP. In females, chico heterozygotes paradoxically produce more rather than less phosphorylated 4E-BP (p4E-BP). Altered IRS function within the IIS pathway of Drosophila appears to have partial, conditional capacity to regulate aging through an unconventional interaction with 4E-BP.

mTORC1 signalling and eIF4E/4E-BP1 translation initiation factor stoichiometry influence recombinant protein productivity from GS-CHOK1 cells.

PubMed

Jossé, Lyne; Xie, Jianling; Proud, Christopher G; Smales, C Mark

2016-12-15

Many protein-based biotherapeutics are produced in cultured Chinese hamster ovary (CHO) cell lines. Recent reports have demonstrated that translation of recombinant mRNAs and global control of the translation machinery via mammalian target of rapamycin (mTOR) signalling are important determinants of the amount and quality of recombinant protein such cells can produce. mTOR complex 1 (mTORC1) is a master regulator of cell growth/division, ribosome biogenesis and protein synthesis, but the relationship between mTORC1 signalling, cell growth and proliferation and recombinant protein yields from mammalian cells, and whether this master regulating signalling pathway can be manipulated to enhance cell biomass and recombinant protein production (rPP) are not well explored. We have investigated mTORC1 signalling and activity throughout batch culture of a panel of sister recombinant glutamine synthetase-CHO cell lines expressing different amounts of a model monoclonal IgG4, to evaluate the links between mTORC1 signalling and cell proliferation, autophagy, recombinant protein expression, global protein synthesis and mRNA translation initiation. We find that the expression of the mTORC1 substrate 4E-binding protein 1 (4E-BP1) fluctuates throughout the course of cell culture and, as expected, that the 4E-BP1 phosphorylation profiles change across the culture. Importantly, we find that the eIF4E/4E-BP1 stoichiometry positively correlates with cell productivity. Furthermore, eIF4E amounts appear to be co-regulated with 4E-BP1 amounts. This may reflect a sensing of either change at the mRNA level as opposed to the protein level or the fact that the phosphorylation status, as well as the amount of 4E-BP1 present, is important in the co-regulation of eIF4E and 4E-BP1. © 2016 The Author(s).

Development of a Geomagnetic Storm Correction to the International Reference Ionosphere E-Region Electron Densities Using TIMED/SABER Observations

NASA Technical Reports Server (NTRS)

Mertens, C. J.; Xu, X.; Fernandez, J. R.; Bilitza, D.; Russell, J. M., III; Mlynczak, M. G.

2009-01-01

Auroral infrared emission observed from the TIMED/SABER broadband 4.3 micron channel is used to develop an empirical geomagnetic storm correction to the International Reference Ionosphere (IRI) E-region electron densities. The observation-based proxy used to develop the storm model is SABER-derived NO+(v) 4.3 micron volume emission rates (VER). A correction factor is defined as the ratio of storm-time NO+(v) 4.3 micron VER to a quiet-time climatological averaged NO+(v) 4.3 micron VER, which is linearly fit to available geomagnetic activity indices. The initial version of the E-region storm model, called STORM-E, is most applicable within the auroral oval region. The STORM-E predictions of E-region electron densities are compared to incoherent scatter radar electron density measurements during the Halloween 2003 storm events. Future STORM-E updates will extend the model outside the auroral oval.

Arginine methyltransferase inhibitor 1 inhibits gastric cancer by downregulating eIF4E and targeting PRMT5.

PubMed

Zhang, Baolai; Zhang, Su; Zhu, Lijuan; Chen, Xue; Zhao, Yunfeng; Chao, Li; Zhou, Juanping; Wang, Xing; Zhang, Xinyang; Ma, Nengqian

2017-12-01

Arginine methylation is carried out by protein arginine methyltransferase (PRMTs) family. Arginine methyltransferase inhibitor 1 (AMI-1) is mainly used to inhibit type I PRMT activity in vitro. However, the effects of AMI-1 on type II PRMT5 activity and gastric cancer (GC) remain unclear. In this study, we provided the first evidence that AMI-1 significantly inhibited GC cell proliferation and migration while induced GC cell apoptosis, and reduced the expression of PRMT5, eukaryotic translation initiation factor 4E (eIF4E), symmetric dimethylation of histone 3 (H3R8me2s) and histone 4 (H4R3me2s). In addition, AMI-1 inhibited tumor growth, downregulated eIF4E, H4R3me2s and H3R8me2s expression in mice xenografts model of GC. Collectively, our results suggest that AMI-1 inhibits GC by downregulating eIF4E and targeting type II PRMT5. Copyright © 2017 Elsevier Inc. All rights reserved.

Kinetically Defined Mechanisms and Positions of Action of Two New Modulators of Glucocorticoid Receptor-regulated Gene Induction*

PubMed Central

Pradhan, Madhumita A.; Blackford, John A.; Devaiah, Ballachanda N.; Thompson, Petria S.; Chow, Carson C.; Singer, Dinah S.; Simons, S. Stoney

2016-01-01

Most of the steps in, and many of the factors contributing to, glucocorticoid receptor (GR)-regulated gene induction are currently unknown. A competition assay, based on a validated chemical kinetic model of steroid hormone action, is now used to identify two new factors (BRD4 and negative elongation factor (NELF)-E) and to define their sites and mechanisms of action. BRD4 is a kinase involved in numerous initial steps of gene induction. Consistent with its complicated biochemistry, BRD4 is shown to alter both the maximal activity (Amax) and the steroid concentration required for half-maximal induction (EC50) of GR-mediated gene expression by acting at a minimum of three different kinetically defined steps. The action at two of these steps is dependent on BRD4 concentration, whereas the third step requires the association of BRD4 with P-TEFb. BRD4 is also found to bind to NELF-E, a component of the NELF complex. Unexpectedly, NELF-E modifies GR induction in a manner that is independent of the NELF complex. Several of the kinetically defined steps of BRD4 in this study are proposed to be related to its known biochemical actions. However, novel actions of BRD4 and of NELF-E in GR-controlled gene induction have been uncovered. The model-based competition assay is also unique in being able to order, for the first time, the sites of action of the various reaction components: GR < Cdk9 < BRD4 ≤ induced gene < NELF-E. This ability to order factor actions will assist efforts to reduce the side effects of steroid treatments. PMID:26504077

Autism-related deficits via dysregulated eIF4E-dependent translational control.

PubMed

Gkogkas, Christos G; Khoutorsky, Arkady; Ran, Israeli; Rampakakis, Emmanouil; Nevarko, Tatiana; Weatherill, Daniel B; Vasuta, Cristina; Yee, Stephanie; Truitt, Morgan; Dallaire, Paul; Major, François; Lasko, Paul; Ruggero, Davide; Nader, Karim; Lacaille, Jean-Claude; Sonenberg, Nahum

2013-01-17

Hyperconnectivity of neuronal circuits due to increased synaptic protein synthesis is thought to cause autism spectrum disorders (ASDs). The mammalian target of rapamycin (mTOR) is strongly implicated in ASDs by means of upstream signalling; however, downstream regulatory mechanisms are ill-defined. Here we show that knockout of the eukaryotic translation initiation factor 4E-binding protein 2 (4E-BP2)-an eIF4E repressor downstream of mTOR-or eIF4E overexpression leads to increased translation of neuroligins, which are postsynaptic proteins that are causally linked to ASDs. Mice that have the gene encoding 4E-BP2 (Eif4ebp2) knocked out exhibit an increased ratio of excitatory to inhibitory synaptic inputs and autistic-like behaviours (that is, social interaction deficits, altered communication and repetitive/stereotyped behaviours). Pharmacological inhibition of eIF4E activity or normalization of neuroligin 1, but not neuroligin 2, protein levels restores the normal excitation/inhibition ratio and rectifies the social behaviour deficits. Thus, translational control by eIF4E regulates the synthesis of neuroligins, maintaining the excitation-to-inhibition balance, and its dysregulation engenders ASD-like phenotypes.

Notch signaling sustains the expression of Mcl-1 and the activity of eIF4E to promote cell survival in CLL

PubMed Central

De Falco, Filomena; Sabatini, Rita; Del Papa, Beatrice; Falzetti, Franca; Di Ianni, Mauro; Sportoletti, Paolo; Baldoni, Stefano; Screpanti, Isabella; Marconi, Pierfrancesco; Rosati, Emanuela

2015-01-01

In chronic lymphocytic leukemia (CLL), Notch1 and Notch2 signaling is constitutively activated and contributes to apoptosis resistance. We show that genetic inhibition of either Notch1 or Notch2, through small-interfering RNA, increases apoptosis of CLL cells and is associated with decreased levels of the anti-apoptotic protein Mcl-1. Thus, Notch signaling promotes CLL cell survival at least in part by sustaining Mcl-1 expression. In CLL cells, an enhanced Notch activation also contributes to the increase in Mcl-1 expression and cell survival induced by IL-4. Mcl-1 downregulation by Notch targeting is not due to reduced transcription or degradation by caspases, but in part, to increased degradation by the proteasome. Mcl-1 downregulation by Notch targeting is also accompanied by reduced phosphorylation of eukaryotic translation initiation factor 4E (eIF4E), suggesting that this protein is another target of Notch signaling in CLL cells. Overall, we show that Notch signaling sustains CLL cell survival by promoting Mcl-1 expression and eIF4E activity, and given the oncogenic role of these factors, we underscore the therapeutic potential of Notch inhibition in CLL. PMID:26041884

Attitudes toward E-Cigarettes, Reasons for Initiating E-Cigarette Use, and Changes in Smoking Behavior after Initiation: A Pilot Longitudinal Study of Regular Cigarette Smokers

PubMed Central

Barr, Dana Boyd; Stratton, Erin; Escoffery, Cam; Kegler, Michelle

2015-01-01

Objectives We examined 1) changes in smoking and vaping behavior and associated cotinine levels and health status among regular smokers who were first-time e-cigarette purchasers and 2) attitudes, intentions, and restrictions regarding e-cigarettes. Methods We conducted a pilot longitudinal study with assessments of the aforementioned factors and salivary cotinine at weeks 0, 4, and 8. Eligibility criteria included being ≥18 years old, smoking ≥25 of the last 30 days, smoking ≥5 cigarettes per day (cpd), smoking regularly ≥1 year, and not having started using e-cigarettes. Of 72 individuals screened, 40 consented, 36 completed the baseline survey, and 83.3% and 72.2% were retained at weeks 4 and 8, respectively. Results Participants reduced cigarette consumption from baseline to week 4 and 8 (p’s < 0.001); 23.1% reported no cigarette use in the past month at week 8. There was no significant decrease in cotinine from baseline to week 4 or 8 (p’s = ns). At week 8, the majority reported improved health (65.4%), reduced smoker’s cough (57.7%), and improved sense of smell (53.8%) and taste (50.0%). The majority believed that e-cigarettes versus regular cigarettes have fewer health risks (97.2%) and that e-cigarettes have been shown to help smokers quit (80.6%) and reduce cigarette consumption (97.2%). In addition, the majority intended to use e-cigarettes as a complete replacement for regular cigarettes (69.4%) and reported no restriction on e-cigarette use in the home (63.9%) or car (80.6%). Conclusions Future research is needed to document the long-term impact on smoking behavior and health among cigarette smokers who initiate use of e-cigarettes. PMID:25621193

Computational Design of Apolipoprotein E4 Inhibitors for Alzheimer's Disease Therapy from Traditional Chinese Medicine

PubMed Central

Huang, Hung-Jin; Chen, Hsin-Yi; Lee, Cheng-Chun

2014-01-01

Apolipoprotein E4 (Apo E4) is the major genetic risk factor in the causation of Alzheimer's disease (AD). In this study we utilize virtual screening of the world's largest traditional Chinese medicine (TCM) database and investigate potential compounds for the inhibition of ApoE4. We present the top three TCM candidates: Solapalmitine, Isodesacetyluvaricin, and Budmunchiamine L5 for further investigation. Dynamics analysis and molecular dynamics (MD) simulation were used to simulate protein-ligand complexes for observing the interactions and protein variations. Budmunchiamine L5 did not have the highest score from virtual screening; however, the dynamics pose is similar to the initial docking pose after MD simulation. Trajectory analysis reveals that Budmunchiamine L5 was stable over all simulation times. The migration distance of Budmunchiamine L5 illustrates that docked ligands are not variable from the initial docked site. Interestingly, Arg158 was observed to form H-bonds with Budmunchiamine L5 in the docking pose and MD snapshot, which indicates that the TCM compounds could stably bind to ApoE4. Our results show that Budmunchiamine L5 has good absorption, blood brain barrier (BBB) penetration, and less toxicity according to absorption, distribution, metabolism, excretion, and toxicity (ADMET) prediction and could, therefore, be safely used for developing novel ApoE4 inhibitors. PMID:24967370

A new eIF4E1 allele characterized by RNAseq data mining is associated with resistance to potato virus Y in tomato albeit with a low durability.

PubMed

Lebaron, Caroline; Rosado, Aurélie; Sauvage, Christopher; Gauffier, Camille; German-Retana, Sylvie; Moury, Benoît; Gallois, Jean-Luc

2016-11-01

Allele mining on susceptibility factors offers opportunities to find new sources of resistance among crop wild relatives for breeding purposes. As a proof of concept, we used available RNAseq data to investigate polymorphisms among the four tomato genes encoding translation initiation factors [eIF4E1 and eIF4E2, eIFiso4E and the related gene new cap-binding protein(nCBP)] to look for new potential resistance alleles to potyviruses. By analysing polymorphism among RNAseq data obtained for 20 tomato accessions, 10 belonging to the cultivated type Solanum lycopersicum and 10 belonging to the closest related wild species Solanum pimpinellifolium, we isolated one new eIF4E1 allele, in the S. pimpinellifolium LA0411 accession, which encodes a potential new resistance allele, mainly due to a polymorphism associated with an amino acid change within eIF4E1 region II. We confirmed that this new allele, pot12, is indeed associated with resistance to potato virus Y, although with a restricted resistance spectrum and a very low durability potential. This suggests that mutations occurring in eIF4E region II only may not be sufficient to provide efficient and durable resistance in plants. However, our study emphasizes the opportunity brought by RNAseq data to mine for new resistance alleles. Moreover, this approach could be extended to seek for putative new resistance alleles by screening for variant forms of susceptibility genes encoding plant host proteins known to interact with viral proteins.

Smad4 and epithelial-mesenchymal transition proteins in colorectal carcinoma: an immunohistochemical study.

PubMed

Ioannou, M; Kouvaras, E; Papamichali, R; Samara, M; Chiotoglou, I; Koukoulis, G

2018-06-01

Epithelial-mesenchymal transition (EMT) plays an important role in cancer metastasis. During EMT, tumor cells acquire the capacity to migrate and invade the stroma. Activation of the transforming growth factor-b (TGF-b) signaling pathway is of major importance for the initiation of EMT. Smad4, an essential protein of this pathway, is known to complex with multiple transcription factors (e.g. Snail-1, Slug, Twist-1), in various types of cancer, promoting the repression or activation of target genes. The role of Smad4 in colorectal cancer (CRC) is not straightforward so far. In the present study forty eight resected CRC tumor specimens were immunohistochemically examined in order to assess the expression of Smad4 and its association with E-cadherin, Snail-1, Slug, Twist-1 protein expression and with various pathological parameters. Smad4 was found to be positively correlated with Snail-1, Slug and Twist-1 expression (p < 0.001). On the other hand it was negatively correlated with the expression of E-cadherin (p < 0.001). Furthermore, lymphatic invasion could be clearly associated with Smad4 expression, a finding complying with the metastatic ability of EMT cells. In conclusion, Smad4 could be considered as a central component of EMT transition in human colorectal cancer that combines with transcriptional factors to reduce E-cadherin and alter the expression of the epithelial phenotype.

Two-Level factorial screening of new plasmid/strain combinations for prodution of recombinant-DNA products.

PubMed

Emborg, C; Jepsen, P K; Biedermann, K

1989-05-01

This article treats the basic problem of selection of experimental conditions for microbiological experiments for evaluation of newly isolated bacterial strains, mutants, or plasmid/strain combinations. For this purpose shake flask experiments in a 2(10-4)confounded factorial design at resolution IV with four blocks of 16 flasks were used. The design was used for testing of two new strain/plasmid combinations (E. coli MT 102/403-SD2 and W 3110/403-SD2) i.e., both strains with the same plasmid 403-SD2. Both strains were integrated in the design, so both strains were tested with nine factors (temperature, aeration, glucose, initial pH, pH regulation, reduced aeration, chloramphenicol, acetate, and glycerol). With both strains the interaction between initial pH and reduced aeration had a significant influence on the yield of the recombinant-DNA product nuclease. There was more than a factor of 10 between lowest and highest yield of product. In this interactive system the strains reacted differently. MT 102/403-SD2 had highest yields at high initial pH (8.4) and no reduction in aeration, whereas W 3110/403-SD2 had highest yields of nuclease at low initial pH (7.4) and reduced aeration (rubber stopper inserted after cultivation for 12 h). These data (and previous work) clearly demonstrate that it is impossible to suggest a simple set of experimental conditions for testing of new plasmid/strain combinations. It is clear that the exclusive application of a standardized growth technique e.g., LB-medium at 37 degrees C at an unspecified and uncontrolled aeration level, may lead to wrong conclusions on properties and potentials of now plasmid/strain combinations and may lead to rejection of useful strains or plasmids.

Heat shock protein-27 (HSP27) regulates STAT3 and eIF4G levels in first trimester human placenta.

PubMed

Shochet, Gali Epstein; Komemi, Oded; Sadeh-Mestechkin, Dana; Pomeranz, Meir; Fishman, Ami; Drucker, Liat; Lishner, Michael; Matalon, Shelly Tartakover

2016-12-01

During placental implantation, cytotrophoblast cells differentiate to extravillous trophoblast (EVT) cells that invade from the placenta into the maternal uterine blood vessels. The heat shock protein-27 (HSP27), the signal transducer and activator of transcription-3 (STAT3) and the eukaryotic translation initiation factor 4E (EIF4E) are involved in regulating EVT cell differentiation/migration. EIF4E and EIF4G compose the translation initiation complex, which is a major control point in protein translation. The molecular chaperone distinctiveness of HSP27 implies that it directly interferes with many target proteins. STAT3, EIF4E, and EIF4G were found to be HSP27 client proteins in tumor cells. We aimed to analyze if HSP27 regulate STAT3 and EIF4G levels in first trimester human placenta. We found that like STAT3, EIF4G is highly expressed in the EVT cells (immunohistochemistry). Silencing HSP27 in HTR-8/SVneo cells (siRNA, EVT cell line) and in placental explants reduced STAT3 level (47 and 33 %, respectively, p < 0.05). HSP27 silencing reduced the levels of STAT3 phosphorylation (33 % reduction, p < 0.05) and targets (IRF1, MUC1, MMP2/9 and EIF4E, 30-49 % reduction, p < 0.05) in the HTR-8/SVneo cells. Moreover, HSP27 silencing significantly reduced EIF4G level and elevated the level of its fragments in HTR-8/SVneo cells and in the placental explants (p < 0.05). In conclusion, Placental implantation and development are accompanied by trophoblast cell proliferation and differentiation, which necessitates intense protein translation and STAT3 activation. HSP27 was found to be regulator of translation initiation and STAT3 level. Therefore, it suggests that HSP27 is a key protein during placental development and trophoblast cell differentiation.

The MNK–eIF4E Signaling Axis Contributes to Injury-Induced Nociceptive Plasticity and the Development of Chronic Pain

PubMed Central

Asiedu, Marina N.; Megat, Salim; Burton, Michael D.; Burgos-Vega, Carolina C.; Melemedjian, Ohannes K.; Boitano, Scott; Vagner, Josef; Pancrazio, Joseph J.; Mogil, Jeffrey S.; Dussor, Gregory

2017-01-01

Injury-induced sensitization of nociceptors contributes to pain states and the development of chronic pain. Inhibiting activity-dependent mRNA translation through mechanistic target of rapamycin and mitogen-activated protein kinase (MAPK) pathways blocks the development of nociceptor sensitization. These pathways convergently signal to the eukaryotic translation initiation factor (eIF) 4F complex to regulate the sensitization of nociceptors, but the details of this process are ill defined. Here we investigated the hypothesis that phosphorylation of the 5′ cap-binding protein eIF4E by its specific kinase MAPK interacting kinases (MNKs) 1/2 is a key factor in nociceptor sensitization and the development of chronic pain. Phosphorylation of ser209 on eIF4E regulates the translation of a subset of mRNAs. We show that pronociceptive and inflammatory factors, such as nerve growth factor (NGF), interleukin-6 (IL-6), and carrageenan, produce decreased mechanical and thermal hypersensitivity, decreased affective pain behaviors, and strongly reduced hyperalgesic priming in mice lacking eIF4E phosphorylation (eIF4ES209A). Tests were done in both sexes, and no sex differences were found. Moreover, in patch-clamp electrophysiology and Ca2+ imaging experiments on dorsal root ganglion neurons, NGF- and IL-6-induced increases in excitability were attenuated in neurons from eIF4ES209A mice. These effects were recapitulated in Mnk1/2−/− mice and with the MNK1/2 inhibitor cercosporamide. We also find that cold hypersensitivity induced by peripheral nerve injury is reduced in eIF4ES209A and Mnk1/2−/− mice and following cercosporamide treatment. Our findings demonstrate that the MNK1/2–eIF4E signaling axis is an important contributing factor to mechanisms of nociceptor plasticity and the development of chronic pain. SIGNIFICANCE STATEMENT Chronic pain is a debilitating disease affecting approximately one in three Americans. Chronic pain is thought to be driven by changes in the excitability of peripheral nociceptive neurons, but the precise mechanisms controlling these changes are not elucidated. Emerging evidence demonstrates that mRNA translation regulation pathways are key factors in changes in nociceptor excitability. Our work demonstrates that a single phosphorylation site on the 5′ cap-binding protein eIF4E is a critical mechanism for changes in nociceptor excitability that drive the development of chronic pain. We reveal a new mechanistic target for the development of a chronic pain state and propose that targeting the upstream kinase, MAPK interacting kinase 1/2, could be used as a therapeutic approach for chronic pain. PMID:28674170

Assessing nicotine dependence in adolescent E-cigarette users: The 4-item Patient-Reported Outcomes Measurement Information System (PROMIS) Nicotine Dependence Item Bank for electronic cigarettes.

PubMed

Morean, Meghan E; Krishnan-Sarin, Suchitra; S O'Malley, Stephanie

2018-04-26

Adolescent e-cigarette use (i.e., "vaping") likely confers risk for developing nicotine dependence. However, there have been no studies assessing e-cigarette nicotine dependence in youth. We evaluated the psychometric properties of the 4-item Patient-Reported Outcomes Measurement Information System Nicotine Dependence Item Bank for E-cigarettes (PROMIS-E) for assessing youth e-cigarette nicotine dependence and examined risk factors for experiencing stronger dependence symptoms. In 2017, 520 adolescent past-month e-cigarette users completed the PROMIS-E during a school-based survey (50.5% female, 84.8% White, 16.22[1.19] years old). Adolescents also reported on sex, grade, race, age at e-cigarette use onset, vaping frequency, nicotine e-liquid use, and past-month cigarette smoking. Analyses included conducting confirmatory factor analysis and examining the internal consistency of the PROMIS-E. Bivariate correlations and independent-samples t-tests were used to examine unadjusted relationships between e-cigarette nicotine dependence and the proposed risk factors. Regression models were run in which all potential risk factors were entered as simultaneous predictors of PROMIS-E scores. The single-factor structure of the PROMIS-E was confirmed and evidenced good internal consistency. Across models, larger PROMIS-E scores were associated with being in a higher grade, initiating e-cigarette use at an earlier age, vaping more frequently, using nicotine e-liquid (and higher nicotine concentrations), and smoking cigarettes. Adolescent e-cigarette users reported experiencing nicotine dependence, which was assessed using the psychometrically sound PROMIS-E. Experiencing stronger nicotine dependence symptoms was associated with characteristics that previously have been shown to confer risk for frequent vaping and tobacco cigarette dependence. Copyright © 2018 Elsevier B.V. All rights reserved.

Archaeal translation initiation revisited: the initiation factor 2 and eukaryotic initiation factor 2B alpha-beta-delta subunit families

NASA Technical Reports Server (NTRS)

Kyrpides, N. C.; Woese, C. R.

1998-01-01

As the amount of available sequence data increases, it becomes apparent that our understanding of translation initiation is far from comprehensive and that prior conclusions concerning the origin of the process are wrong. Contrary to earlier conclusions, key elements of translation initiation originated at the Universal Ancestor stage, for homologous counterparts exist in all three primary taxa. Herein, we explore the evolutionary relationships among the components of bacterial initiation factor 2 (IF-2) and eukaryotic IF-2 (eIF-2)/eIF-2B, i.e., the initiation factors involved in introducing the initiator tRNA into the translation mechanism and performing the first step in the peptide chain elongation cycle. All Archaea appear to posses a fully functional eIF-2 molecule, but they lack the associated GTP recycling function, eIF-2B (a five-subunit molecule). Yet, the Archaea do posses members of the gene family defined by the (related) eIF-2B subunits alpha, beta, and delta, although these are not specifically related to any of the three eukaryotic subunits. Additional members of this family also occur in some (but by no means all) Bacteria and even in some eukaryotes. The functional significance of the other members of this family is unclear and requires experimental resolution. Similarly, the occurrence of bacterial IF-2-like molecules in all Archaea and in some eukaryotes further complicates the picture of translation initiation. Overall, these data lend further support to the suggestion that the rudiments of translation initiation were present at the Universal Ancestor stage.

Education for eHealth--a status analysis.

PubMed

Herzog, Juliane; Pohn, Birgit; Forjan, Mathias; Sauermann, Stefan; Urbauer, Philipp

2014-01-01

eHealth is not only a growing market, but also an important factor for new healthcare systems. National and European initiatives implicitly demand a higher level of knowledge in the areas of healthcare, engineering and management. As part of the eLearning4eHealth project an initial web based study was performed concentrating on European and global eHealth related educational programs. The results show that eHealth related courses do not evenly exist for the identified professions. 43% of the offered programs are focused on the engineering sector, whereas only 21% are available for the management sector. In order to offer compatible and comparable state of knowledge in the identified fields of profession and knowledge, further educational programs may be necessary. Despite the found shortcomings, results have shown that international activities have started in order to close the gaps and improve the quality of knowledge in the interdisciplinary field of eHealth.

Yeast eIF4A enhances recruitment of mRNAs regardless of their structural complexity

PubMed Central

Yourik, Paul; Aitken, Colin Echeverría; Zhou, Fujun; Gupta, Neha

2017-01-01

eIF4A is a DEAD-box RNA-dependent ATPase thought to unwind RNA secondary structure in the 5'-untranslated regions (UTRs) of mRNAs to promote their recruitment to the eukaryotic translation pre-initiation complex (PIC). We show that eIF4A's ATPase activity is markedly stimulated in the presence of the PIC, independently of eIF4E•eIF4G, but dependent on subunits i and g of the heteromeric eIF3 complex. Surprisingly, eIF4A accelerated the rate of recruitment of all mRNAs tested, regardless of their degree of structural complexity. Structures in the 5'-UTR and 3' of the start codon synergistically inhibit mRNA recruitment in a manner relieved by eIF4A, indicating that the factor does not act solely to melt hairpins in 5'-UTRs. Our findings that eIF4A functionally interacts with the PIC and plays important roles beyond unwinding 5'-UTR structure is consistent with a recent proposal that eIF4A modulates the conformation of the 40S ribosomal subunit to promote mRNA recruitment. PMID:29192585

Protein synthesis in skeletal muscle of neonatal pigs is enhanced by administration of β-hydroxy-β-methylbutyrate

PubMed Central

Wheatley, Scott M.; El-Kadi, Samer W.; Suryawan, Agus; Boutry, Claire; Orellana, Renán A.; Nguyen, Hanh V.; Davis, Steven R.

2013-01-01

Many low-birth-weight infants experience failure to thrive. The amino acid leucine stimulates protein synthesis in skeletal muscle of the neonate, but less is known about the effects of the leucine metabolite β-hydroxy-β-methylbutyrate (HMB). To determine the effects of HMB on protein synthesis and the regulation of translation initiation and degradation pathways, overnight-fasted neonatal pigs were infused with HMB at 0, 20, 100, or 400 μmol·kg body wt−1·h−1 for 1 h (HMB 0, HMB 20, HMB 100, or HMB 400). Plasma HMB concentrations increased with infusion and were 10, 98, 316, and 1,400 nmol/ml in the HMB 0, HMB 20, HMB 100, and HMB 400 pigs. Protein synthesis rates in the longissimus dorsi (LD), gastrocnemius, soleus, and diaphragm muscles, lung, and spleen were greater in HMB 20 than in HMB 0, and in the LD were greater in HMB 100 than in HMB 0. HMB 400 had no effect on protein synthesis. Eukaryotic initiation factor (eIF)4E·eIF4G complex formation and ribosomal protein S6 kinase-1 and 4E-binding protein-1 phosphorylation increased in LD, gastrocnemius, and soleus muscles with HMB 20 and HMB 100 and in diaphragm with HMB 20. Phosphorylation of eIF2α and elongation factor 2 and expression of system A transporter (SNAT2), system L transporter (LAT1), muscle RING finger 1 protein (MuRF1), muscle atrophy F-box (atrogin-1), and microtubule-associated protein light chain 3 (LC3-II) were unchanged. Results suggest that supplemental HMB enhances protein synthesis in skeletal muscle of neonates by stimulating translation initiation. PMID:24192287

p97/DAP5 is a ribosome-associated factor that facilitates protein synthesis and cell proliferation by modulating the synthesis of cell cycle proteins

PubMed Central

Lee, Sang Hyun; McCormick, Frank

2006-01-01

p97 (also referred to as DAP5, NAT1 or eIF4G2) has been proposed to act as a repressor of protein synthesis. However, we found that p97 is abundantly expressed in proliferating cells and p97 is recruited to ribosomes following growth factor stimulation. We also report that p97 binds eIF2β through its C-terminal domain and localizes to ribosome through its N-terminal MIF4G domain. When overexpressed, p97 increases reporter luciferase activity. In contrast, overexpression of the C-terminal two-thirds of eukaryotic initiation factor 4GI (eIF4GI), a region that shares significant homology with p97, or the N-terminal MIF4G domain of p97 markedly inhibits reporter activity, the rate of global translation and cell proliferation. Conversely, downregulation of p97 levels by RNA interference also decreases the rate of global translation and inhibits cell proliferation. This coincides with an increase in p27/Kip1 protein levels and a marked decrease in CDK2 kinase activity. Taken together, our results demonstrate that p97 is functionally different from the closely related C-terminal two-thirds of eIF4GI and it can positively promote protein synthesis and cell proliferation. PMID:16932749

EGF does not induce Msx-1 and Msx-2 in dental mesenchyme.

PubMed

Wang, Y H; Kollar, E J; Upholt, W B; Mina, M

1998-01-01

Previous heterospecific tissue recombinations indicate that mandibular epithelium exerts the first known inductive signal for odontogenesis in mouse embryos. BMP-4 and EGF are two growth factors implicated as signaling molecules mediating the initial inductive epithelial-mesenchymal interactions during odontogenesis. The purpose of the present study was to examine and compare the effects of these growth factors and mouse mandibular epithelium on expression of Msx-1 and Msx-2 genes in molar-forming mesenchyme. Agarose beads soaked in growth factors or pieces of mouse mandibular epithelium (E11) were placed in contact with E11 molar-forming mesenchyme and cultured for 24 h. Whole-mount in situ hybridization analysis revealed that, in contrast to mouse mandibular epithelium and BMP-4-releasing beads, EGF-releasing beads did not induce the expression of Msx-1 and Msx-2 in E11 molar-forming mesenchyme. These observations suggest that whereas BMP-4 may be involved in activation of Msx-1 and Msx-2 in the underlying mesenchyme, EGF may regulate events involved in the formation of dental lamina.

Interaction of maternal atopy, CTLA-4 gene polymorphism and gender on antenatal immunoglobulin E production.

PubMed

Yang, K D; Ou, C-Y; Hsu, T-Y; Chang, J-C; Chuang, H; Liu, C-A; Liang, H-M; Kuo, H-C; Chen, R-F; Huang, E-Y

2007-05-01

Genetic heritability and maternal atopy have been correlated to antenatal IgE production, but very few studies have studied gene-maternal atopy interaction on antenatal IgE production. This study investigated the interaction of CTLA-4 polymorphism with prenatal factors on the elevation of cord blood IgE (CBIgE). Pregnant women were antenatally recruited for collection of prenatal environmental factors by a questionnaire. Umbilical cord blood samples were collected for CBIgE detection by fluorescence-linked enzyme assay and CTLA-4 polymorphism measurement by restriction fragment length polymorphism. A total of 1104 pregnant women initially participated in this cohort study, and 898 of them completed cord blood collection. 21.4% of the newborns had elevation of CBIgE (>or=0.5 kU/L). The CTLA-4+49A allele (P=0.021), maternal atopy (P<0.001) and gender (P=0.034), but not the CTLA-4+49G allele, -318C allele, -318T allele, parental smoking or paternal atopy, were significantly correlated with the CBIgE elevation in multivariate analysis. A dichotomous analysis of gene-maternal atopy interactions identified maternal atopy and CTLA-4+49A allele had an additive effect on the CBIgE elevation, especially prominent in male newborns; and in the absence of maternal atopy, CTLA-4+49GG genotype had a protective effect on CBIgE elevation in female newborns. Maternal but not paternal atopy has significant impacts on CBIgE elevation depending on gender and CTLA-4+49A/G polymorphism of newborns. Control of maternal atopy and modulation of CTLA-4 expression in the prenatal stage may be a target for the early prevention of perinatal allergy sensitization.

Yeast eIF4B binds to the head of the 40S ribosomal subunit and promotes mRNA recruitment through its N-terminal and internal repeat domains.

PubMed

Walker, Sarah E; Zhou, Fujun; Mitchell, Sarah F; Larson, Victoria S; Valasek, Leos; Hinnebusch, Alan G; Lorsch, Jon R

2013-02-01

Eukaryotic translation initiation factor (eIF)4B stimulates recruitment of mRNA to the 43S ribosomal pre-initiation complex (PIC). Yeast eIF4B (yeIF4B), shown previously to bind single-stranded (ss) RNA, consists of an N-terminal domain (NTD), predicted to be unstructured in solution; an RNA-recognition motif (RRM); an unusual domain comprised of seven imperfect repeats of 26 amino acids; and a C-terminal domain. Although the mechanism of yeIF4B action has remained obscure, most models have suggested central roles for its RRM and ssRNA-binding activity. We have dissected the functions of yeIF4B's domains and show that the RRM and its ssRNA-binding activity are dispensable in vitro and in vivo. Instead, our data indicate that the 7-repeats and NTD are the most critical domains, which mediate binding of yeIF4B to the head of the 40S ribosomal subunit via interaction with Rps20. This interaction induces structural changes in the ribosome's mRNA entry channel that could facilitate mRNA loading. We also show that yeIF4B strongly promotes productive interaction of eIF4A with the 43S•mRNA PIC in a manner required for efficient mRNA recruitment.

Probing the closed-loop model of mRNA translation in living cells

PubMed Central

Archer, Stuart K; Shirokikh, Nikolay E; Hallwirth, Claus V; Beilharz, Traude H; Preiss, Thomas

2015-01-01

The mRNA closed-loop, formed through interactions between the cap structure, poly(A) tail, eIF4E, eIF4G and PAB, features centrally in models of eukaryotic translation initiation, although direct support for its existence in vivo is not well established. Here, we investigated the closed-loop using a combination of mRNP isolation from rapidly cross-linked cells and high-throughput qPCR. Using the interaction between these factors and the opposing ends of mRNAs as a proxy for the closed-loop, we provide evidence that it is prevalent for eIF4E/4G-bound but unexpectedly sparse for PAB1-bound mRNAs, suggesting it primarily occurs during a distinct phase of polysome assembly. We observed mRNA-specific variation in the extent of closed-loop formation, consistent with a role for polysome topology in the control of gene expression. PMID:25826658

Genetic Variation in the Transforming Growth Factor-β Signaling Pathway and Survival After Diagnosis With Colon and Rectal Cancer

PubMed Central

Slattery, Martha L.; Lundgreen, Abbie; Herrick, Jennifer S.; Wolff, Roger K.; Caan, Bette J.

2012-01-01

BACKGROUND The transforming growth factor-β (TGF-β) signaling pathway is involved in many aspects of tumori-genesis, including angiogenesis and metastasis. The authors evaluated this pathway in association with survival after a diagnosis of colon or rectal cancer. METHODS The study included 1553 patients with colon cancer and 754 patients with rectal cancer who had incident first primary disease and were followed for a minimum of 7 years after diagnosis. Genetic variations were evaluated in the genes TGF-β1 (2 single nucleotide polymorphisms [SNPs]), TGF-β receptor 1 (TGF-βR1) (3 SNPs), smooth muscle actin/mothers against decapentaplegic homolog 1 (Smad1) (5 SNPs), Smad2 (4 SNPs), Smad3 (37 SNPs), Smad4 (2 SNPs), Smad7 (11 SNPs), bone morphogenetic protein 1 (BMP1) (11 SNPs), BMP2 (5 SNPs), BMP4 (3 SNPs), bone morphogenetic protein receptor 1A (BMPR1A) (9 SNPs), BMPR1B (21 SNPs), BMPR2 (11 SNPs), growth differentiation factor 10 (GDF10) (7 SNPs), Runt-related transcription factor 1 (RUNX1) (40 SNPs), RUNX2 (19 SNPs), RUNX3 (9 SNPs), eukaryotic translation initiation factor 4E (eiF4E) (3 SNPs), eukaryotic translation initiation factor 4E-binding protein 3 (eiF4EBP2) (2 SNPs), eiF4EBP3 (2 SNPs), and mitogen-activated protein kinase 1 (MAPK1) (6 SNPs). RESULTS After adjusting for American Joint Committee on Cancer stage and tumor molecular phenotype, 12 genes and 18 SNPs were associated with survival in patients with colon cancer, and 7 genes and 15 tagSNPs were associated with survival after a diagnosis of rectal cancer. A summary score based on “at-risk” genotypes revealed a hazard rate ratio of 5.10 (95% confidence interval, 2.56-10.15) for the group with the greatest number of “at-risk” genotypes; for rectal cancer, the hazard rate ratio was 6.03 (95% confidence interval, 2.83-12.75). CONCLUSIONS The current findings suggest that the presence of several higher risk alleles in the TGF-β signaling pathway increase the likelihood of dying after a diagnosis of colon or rectal cancer. PMID:21365634

High eIF4E, VEGF, and Microvessel Density in Stage I to III Breast Cancer

PubMed Central

Byrnes, Kerry; White, Stephen; Chu, Quyen; Meschonat, Carol; Yu, Herbert; Johnson, Lester W.; DeBenedetti, Arrigo; Abreo, Fleurette; Turnage, Richard H.; McDonald, John C.; Li, Benjamin D.

2006-01-01

Objective: In a prospective trial, to determine if eIF4E overexpression in breast cancer specimens is correlated with VEGF elevation, increased tumor microvessel density (MVD) counts, and a worse clinical outcome irrespective of nodal status. Summary and Background Data: In vitro, the overexpression of eukaryotic initiation factor 4E (eIF4E) up-regulates the translation of mRNAs with long 5′-untranslated regions (5′-UTRs). One such gene product is the vascular endothelial growth factor (VEGF). Methods: A total of 114 stage I to III breast cancer patients were prospectively accrued and followed with a standardized clinical surveillance protocol. Cancer specimens were quantified for eIF4E, VEGF, and MVD. Outcome endpoints were cancer recurrence and cancer-related death. Results: eIF4E overexpression was found in all cancer specimens (mean ± SD, 12.5 ± 7.6-fold). Increasing eIF4E overexpression correlated with increasing VEGF elevation (r = 0.24, P = 0.01, Spearman's coefficient), and increasing MVD counts (r = 0.35, P < 0.0002). Patients whose tumor had high eIF4E overexpression had shorter disease-free survival (P = 0.004, log-rank test) and higher cancer-related deaths (P = 0.002) than patients whose tumors had low eIF4E overexpression. Patients with high eIF4E had a hazard ratio for cancer recurrence and cancer-related death of 1.8 and 2.1 times that of patients with low eIF4E (respectively, P = 0.009 and P = 0.002, Cox proportional hazard model). Conclusions: In breast cancer patients, increasing eIF4E overexpression in the cancer specimens correlates with higher VEGF levels and MVD counts. Patients whose tumors had high eIF4E overexpression had a worse clinical outcome, independent of nodal status. Thus, eIF4E overexpression in breast cancer appears to predict increased tumor vascularity and perhaps cancer dissemination by hematogenous means. PMID:16633004

Medium optimization by orthogonal array and response surface methodology for cholesterol oxidase production by Streptomyces lavendulae NCIM 2499.

PubMed

Chauhan, Awadesh K; Survase, Shrikant A; Kishenkumar, Jyoti; Annapure, Uday S

2009-06-01

This paper deals with the optimization of culture conditions for the production of cholesterol oxidase (COD) by Streptomyces lavendulae NCIM 2499 using the one-factor-at-a-time method, orthogonal array method and response surface methodology (RSM) approaches. The one-factor-at-a-time method was adopted to investigate the effects of medium components (i.e. carbon and nitrogen) and environmental factors (i.e. initial pH) on biomass growth and COD production. Subsequently, an L12 orthogonal matrix was used to evaluate the significance of glycerol, soyabean meal, malt extract, K2HPO4, MgSO4 and NaCl. The effects of media components were ranked according to their effects on the production of COD as malt extract > soyabean meal > K2HPO4 > NaCl > MgSO4 > glycerol. The subsequent optimization of the four most significant factors viz. malt extract, soyabean meal, K2HPO4 and NaCl, was carried out by employing a central composite rotatable design (CCRD) of RSM. There was a 2.48-fold increase in productivity of COD as compared to the unoptimized media by using these statistical approaches.

Phosphoproteomic Analysis of Signaling Pathways in Head and Neck Squamous Cell Carcinoma Patient Samples

PubMed Central

Frederick, Mitchell J.; VanMeter, Amy J.; Gadhikar, Mayur A.; Henderson, Ying C.; Yao, Hui; Pickering, Curtis C.; Williams, Michelle D.; El-Naggar, Adel K.; Sandulache, Vlad; Tarco, Emily; Myers, Jeffrey N.; Clayman, Gary L.; Liotta, Lance A.; Petricoin, Emanuel F.; Calvert, Valerie S.; Fodale, Valentina; Wang, Jing; Weber, Randal S.

2011-01-01

Molecular targeted therapy represents a promising new strategy for treating cancers because many small-molecule inhibitors targeting protein kinases have recently become available. Reverse-phase protein microarrays (RPPAs) are a useful platform for identifying dysregulated signaling pathways in tumors and can provide insight into patient-specific differences. In the present study, RPPAs were used to examine 60 protein end points (predominantly phosphoproteins) in matched tumor and nonmalignant biopsy specimens from 23 patients with head and neck squamous cell carcinoma to characterize the cancer phosphoproteome. RPPA identified 18 of 60 analytes globally elevated in tumors versus healthy tissue and 17 of 60 analytes that were decreased. The most significantly elevated analytes in tumor were checkpoint kinase (Chk) 1 serine 345 (S345), Chk 2 S33/35, eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) S65, protein kinase C (PKC) ζ/ι threonine 410/412 (T410/T412), LKB1 S334, inhibitor of kappaB alpha (IκB-α) S32, eukaryotic translation initiation factor 4E (eIF4E) S209, Smad2 S465/67, insulin receptor substrate 1 (IRS-1) S612, mitogen-activated ERK kinase 1/2 (MEK1/2) S217/221, and total PKC ι. To our knowledge, this is the first report of elevated PKC ι in head and neck squamous cell carcinoma that may have significance because PKC ι is an oncogene in several other tumor types, including lung cancer. The feasibility of using RPPA for developing theranostic tests to guide personalized therapy is discussed in the context of these data. PMID:21281788

Remodeling of the pioneer translation initiation complex involves translation and the karyopherin importin β

PubMed Central

Sato, Hanae; Maquat, Lynne E.

2009-01-01

Mammalian mRNAs lose and acquire proteins throughout their life span while undergoing processing, transport, translation, and decay. How translation affects messenger RNA (mRNA)–protein interactions is largely unknown. The pioneer round of translation uses newly synthesized mRNA that is bound by cap-binding protein 80 (CBP80)–CBP20 (also known as the cap-binding complex [CBC]) at the cap, poly(A)-binding protein N1 (PABPN1) and PABPC1 at the poly(A) tail, and, provided biogenesis involves pre-mRNA splicing, exon junction complexes (EJCs) at exon–exon junctions. Subsequent rounds of translation engage mRNA that is bound by eukaryotic translation initiation factor 4E (eIF4E) at the cap and PABPC1 at the poly(A) tail, but that lacks detectable EJCs and PABPN1. Using the level of intracellular iron to regulate the translation of specific mRNAs, we show that translation promotes not only removal of EJC constituents, including the eIF4AIII anchor, but also replacement of PABPN1 by PABPC1. Remarkably, translation does not affect replacement of CBC by eIF4E. Instead, replacement of CBC by eIF4E is promoted by importin β (IMPβ): Inhibiting the binding of IMPβ to the complex of CBC–IMPα at an mRNA cap using the IMPα IBB (IMPβ-binding) domain or a RAN variant increases the amount of CBC-bound mRNA and decreases the amount of eIF4E-bound mRNA. Our studies uncover a previously unappreciated role for IMPβ and a novel paradigm for how newly synthesized messenger ribonucleoproteins (mRNPs) are matured. PMID:19884259

Transcriptome-wide studies uncover the diversity of modes of mRNA recruitment to eukaryotic ribosomes.

PubMed

Shatsky, Ivan N; Dmitriev, Sergey E; Andreev, Dmitri E; Terenin, Ilya M

2014-01-01

The conventional paradigm of translation initiation in eukaryotes states that the cap-binding protein complex eIF4F (consisting of eIF4E, eIF4G and eIF4A) plays a central role in the recruitment of capped mRNAs to ribosomes. However, a growing body of evidence indicates that this paradigm should be revised. This review summarizes the data which have been mostly accumulated in a post-genomic era owing to revolutionary techniques of transcriptome-wide analysis. Unexpectedly, these techniques have uncovered remarkable diversity in the recruitment of cellular mRNAs to eukaryotic ribosomes. These data enable a preliminary classification of mRNAs into several groups based on their requirement for particular components of eIF4F. They challenge the widely accepted concept which relates eIF4E-dependence to the extent of secondary structure in the 5' untranslated regions of mRNAs. Moreover, some mRNA species presumably recruit ribosomes to their 5' ends without the involvement of either the 5' m(7)G-cap or eIF4F but instead utilize eIF4G or eIF4G-like auxiliary factors. The long-standing concept of internal ribosome entry site (IRES)-elements in cellular mRNAs is also discussed.

Unfolded Protein Response and PERK Kinase as a New Therapeutic Target in the Pathogenesis of Alzheimer's Disease.

PubMed

Rozpedek, Wioletta; Markiewicz, Lukasz; Diehl, J Alan; Pytel, Dariusz; Majsterek, Ireneusz

2015-01-01

Recent evidence suggests that the development of Alzheimer's disease (AD) and related cognitive loss is due to mutations in the Amyloid Precursor Protein (APP) gene on chromosome 21 and increased activation of eukaryotic translation initiation factor-2α (eIF2α) phosphorylation. The high level of misfolded and unfolded proteins loading in Endoplasmic Reticulum (ER) lumen triggers ER stress and as a result Unfolded Protein Response (UPR) pathways are activated. Stress-dependent activation of the protein kinase RNA-like endoplasmic reticulum kinase (PERK) leads to the significant elevation of phospho-eIF2α. That attenuates general translation and, on the other hand, promotes the preferential synthesis of Activating Transcription Factor 4 (ATF4) and secretase β (BACE1) - a pivotal enzyme responsible for the initiation of the amyloidogenic pathway resulting in the generation of the amyloid β (Aβ) variant with high ability to form toxic senile plaques in AD brains. Moreover, excessive, long-term stress conditions may contribute to inducing neuronal death by apoptosis as a result of the overactivated expression of pro-apoptotic proteins via ATF4. These findings allow to infer that dysregulated translation, increased expression of BACE1 and ATF4, as a result of eIF2α phosphorylation, may be a major contributor to structural and functional neuronal loss resulting in memory impairment. Thus, blocking PERK-dependent eIF2α phosphorylation through specific, small-molecule PERK branch inhibitors seems to be a potential treatment strategy for AD individuals. That may contribute to the restoration of global translation rates and reduction of expression of ATF4 and BACE1. Hence, the treatment strategy can block accelerated β -amyloidogenesis by reduction in APP cleaving via the BACE1-dependent amyloidogenic pathway.

Evaluation of the Self-Stigma of Stuttering Scale (4S)

ERIC Educational Resources Information Center

Boyle, Michael P.

2013-01-01

Purpose: To create a psychometrically sound scale that measures different levels of internalized stigma (i.e., self-stigma) among adults who stutter and to analyze factor structure, reliability, and initial construct validity of the scale. Method: Two-hundred ninety-one adults who stutter were recruited from Board Recognized Specialists in Fluency…

The predictive factors of α1-D/A adrenoceptor antagonist, naftopidil, dose increase therapy for male lower urinary tract symptoms caused by benign prostatic hyperplasia: INFORM study.

PubMed

Tanuma, Yasushi; Tanaka, Yoshinori; Takeyama, Ko; Okamoto, Tomoshi

2017-01-01

We evaluated the predictive factors which affect the efficacy of naftopidil 50 mg/day therapy and dose increase therapy to administration of 75 mg/day after an initial dose of 50 mg/day. A total of 92 patients with male lower urinary tract symptoms/benign prostatic hyperplasia were administrated naftopidil 50 mg/day for 4 weeks (50 mg therapy). At week 4, the patients were divided into an effective and an ineffective group (Group E and Group I, respectively). For further 4 weeks, the dosage of naftopidil was increased to 75 mg/day in all patients. At week 8, the patients of Group E and Group I were divided into an effective and an ineffective group (Group EE, Group EI, Group IE, and Group II, respectively). Postvoid residual (PVR) urine volume at baseline was a predictive factor for efficacy of 50 mg therapy. In Group E, change in International Prostate Symptom Score storage symptoms subscore from baseline to week 4 was a predictive factor for efficacy of this dose increase therapy. In Group I, change in maximum flow rate from baseline to week 4 was a predictive factor for efficacy of this dose increase therapy. The short term of naftopidil 50 mg therapy was ineffective for the patients who had large PVR. The predictive factor of this dose increase therapy might be a dynamic variable in 50 mg/day of dose period, but not a baseline variable at the time of 75 mg/day dosage starts.

Emodin inhibits coxsackievirus B3 replication via multiple signalling cascades leading to suppression of translation.

PubMed

Zhang, Huifang M; Wang, Fengping; Qiu, Ye; Ye, Xin; Hanson, Paul; Shen, Hongxing; Yang, Decheng

2016-02-15

CVB3 (coxsackievirus 3) is a primary causal agent of viral myocarditis. Emodin is a natural compound isolated from certain plant roots. In the present study, we found that emodin inhibited CVB3 replication in vitro and in mice, and now we report an unrecognized mechanism by which emodin inhibits CVB3 replication through suppression of viral protein translation via multiple pathways. On one hand, emodin treatment inhibited Akt/mTOR (mammalian target of rapamycin) signalling and activated 4EBP1 (eukaryotic initiation factor 4R-binding protein 1), leading to suppression of translation initiation of ribosomal protein L32 encoded by a 5'-TOP (terminal oligopyrimidine) mRNA. On the other hand, emodin treatment differentially regulated multiple signal cascades, including Akt/mTORC1/p70(S6K) (p70 S6 kinase), ERK1/2 (extracellular-signal-regulated kinase 1/2)/p90(RSK) (p90 ribosomal S6 kinase) and Ca(2+)/calmodulin, leading to activation of eEF2K (eukaryotic elongation factor 2 kinase) and subsequent inactivation of eEF2 (eukaryotic elongation factor 2), resulting in inhibition of CVB3 VP1 (viral protein 1) synthesis. These data imply that eEF2K is a major factor mediating cross-talk of different arms of signalling cascades in this signal network. This notion was verified by either overexpressing eEF2K or treating the cells with siRNAs or eEF2K inhibitor A484954. We showed further that the emodin-induced decrease in p70(S6K) phosphorylation plays a dominant positive role in activation of eEF2K and in turn in conferring the antiviral effect of emodin. This finding was further solidified by expressing constitutively active and dominant-negative Akt. Collectively, our data reveal that emodin inhibits viral replication through impairing translational machinery and suppression of viral translation elongation. © 2016 Authors; published by Portland Press Limited.

Distinct Contributory Factors Determine Basophil-Allergen Sensitivity in Grass Pollen Rhinitis and in Anaphylactic Wasp Venom Allergy.

PubMed

Korošec, Peter; Šilar, Mira; Kopač, Peter; Eržen, Renato; Zidarn, Mihaela; Košnik, Mitja

2016-01-01

We sought to determine whether basophil-allergen sensitivity could be transferred to donor basophils by passive IgE sensitisation in allergic rhinitis and anaphylactic Hymenoptera venom hypersensitivity. We studied 15 wasp venom-, 19 grass pollen- and 2 house dust mite-allergic patients, 2 healthy donors, and 8 wasp venom-allergic donors. In all subjects, we first evaluated the initial basophil response to wasp venom, grass pollen, or house dust mite allergen. Donor basophils were then stripped, sensitised with the different patients' serum IgE, and challenged with the corresponding allergen. The CD63 response of donor basophils was then compared with initial basophil responses. In wasp venom-allergic subjects, the IgE transfer did not reflect the initial basophil-allergen sensitivity, because the venom IgE of subjects with high or low basophil sensitivity induced comparable responsiveness in healthy donor basophils. Furthermore, vice versa, when we sensitised the donor basophils of wasp venom-allergic individuals with different wasp venom or house dust mite IgE, we demonstrated that their response was predictable by their initial basophil allergen sensitivity. In the rhinitis allergy model, the IgE transfer correlated with the patients' initial basophil responsiveness because the grass pollen IgE of the subjects with high basophil allergen sensitivity induced significantly higher responsiveness of donor basophils than the IgE of subjects with initially low basophil allergen sensitivity. Our results suggest that basophil allergen sensitivity evaluated by flow-cytometric CD63 analysis depends on two distinct contribution factors. In anaphylactic Hymenoptera allergy, the major factor was intrinsic cellular sensitivity, whereas in pollen allergy, the major factor was allergen-specific IgE on the cell surface. © 2016 S. Karger AG, Basel.

Sustainability Factors for E-Learning Initiatives

ERIC Educational Resources Information Center

Gunn, Cathy

2010-01-01

This paper examines the challenges that "grass roots" e-learning initiatives face in trying to become sustainable. A cross-institutional study focused on local, rather than centrally driven, initiatives. A number of successful e-learning innovations were identified that had been driven by capable teachers seeking solutions to real…

Yeast eIF4B binds to the head of the 40S ribosomal subunit and promotes mRNA recruitment through its N-terminal and internal repeat domains

PubMed Central

Walker, Sarah E.; Zhou, Fujun; Mitchell, Sarah F.; Larson, Victoria S.; Valasek, Leos; Hinnebusch, Alan G.; Lorsch, Jon R.

2013-01-01

Eukaryotic translation initiation factor (eIF)4B stimulates recruitment of mRNA to the 43S ribosomal pre-initiation complex (PIC). Yeast eIF4B (yeIF4B), shown previously to bind single-stranded (ss) RNA, consists of an N-terminal domain (NTD), predicted to be unstructured in solution; an RNA-recognition motif (RRM); an unusual domain comprised of seven imperfect repeats of 26 amino acids; and a C-terminal domain. Although the mechanism of yeIF4B action has remained obscure, most models have suggested central roles for its RRM and ssRNA-binding activity. We have dissected the functions of yeIF4B’s domains and show that the RRM and its ssRNA-binding activity are dispensable in vitro and in vivo. Instead, our data indicate that the 7-repeats and NTD are the most critical domains, which mediate binding of yeIF4B to the head of the 40S ribosomal subunit via interaction with Rps20. This interaction induces structural changes in the ribosome’s mRNA entry channel that could facilitate mRNA loading. We also show that yeIF4B strongly promotes productive interaction of eIF4A with the 43S•mRNA PIC in a manner required for efficient mRNA recruitment. PMID:23236192

Neurotrophin-4 regulates the survival of gustatory neurons earlier in development using a different mechanism than brain-derived neurotrophic factor.

PubMed

Patel, Ami V; Krimm, Robin F

2012-05-01

The number of neurons in the geniculate ganglion that are available to innervate taste buds is regulated by neurotrophin-4 (NT-4) and brain-derived neurotrophic factor (BDNF). Our goal for the current study was to examine the timing and mechanism of NT-4-mediated regulation of geniculate neuron number during development. We discovered that NT-4 mutant mice lose 33% of their geniculate neuronal cells between E10.5 and E11.5. By E11.5, geniculate axons have just reached the tongue and do not yet innervate their gustatory targets; thus, NT-4 does not function as a target-derived growth factor. At E11.5, no difference was observed in proliferating cells or the rate at which cells exit the cell cycle between NT-4 mutant and wild type ganglia. Instead, there was an increase in TUNEL-labeling, indicating an increase in cell death in Ntf4(-/-) mice compared with wild types. However, activated caspase-3, which is up-regulated in the absence of BDNF, was not increased. This finding indicates that cell death initiated by NT-4-removal occurs through a different cell death pathway than BDNF-removal. We observed no additional postnatal loss of taste buds or neurons in Ntf4(-/-) mice. Thus, during early embryonic development, NT-4 produced in the ganglion and along the projection pathway inhibits cell death through an activated caspase-3 independent mechanism. Therefore, compared to BDNF, NT-4 plays distinct roles in gustatory development; differences include timing, source of neurotrophin, and mechanism of action. Published by Elsevier Inc.

Mutational Analysis of Plant Cap-Binding Protein eIF4E Reveals Key Amino Acids Involved in Biochemical Functions and Potyvirus Infection▿

PubMed Central

German-Retana, Sylvie; Walter, Jocelyne; Doublet, Bénédicte; Roudet-Tavert, Geneviève; Nicaise, Valérie; Lecampion, Cécile; Houvenaghel, Marie-Christine; Robaglia, Christophe; Michon, Thierry; Le Gall, Olivier

2008-01-01

The eukaryotic translation initiation factor 4E (eIF4E) (the cap-binding protein) is involved in natural resistance against several potyviruses in plants. In lettuce, the recessive resistance genes mo11 and mo12 against Lettuce mosaic virus (LMV) are alleles coding for forms of eIF4E unable, or less effective, to support virus accumulation. A recombinant LMV expressing the eIF4E of a susceptible lettuce variety from its genome was able to produce symptoms in mo11 or mo12 varieties. In order to identify the eIF4E amino acid residues necessary for viral infection, we constructed recombinant LMV expressing eIF4E with point mutations affecting various amino acids and compared the abilities of these eIF4E mutants to complement LMV infection in resistant plants. Three types of mutations were produced in order to affect different biochemical functions of eIF4E: cap binding, eIF4G binding, and putative interaction with other virus or host proteins. Several mutations severely reduced the ability of eIF4E to complement LMV accumulation in a resistant host and impeded essential eIF4E functions in yeast. However, the ability of eIF4E to bind a cap analogue or to fully interact with eIF4G appeared unlinked to LMV infection. In addition to providing a functional mutational map of a plant eIF4E, this suggests that the role of eIF4E in the LMV cycle might be distinct from its physiological function in cellular mRNA translation. PMID:18480444

Ion collection from a plasma by a pinhole

NASA Technical Reports Server (NTRS)

Snyder, David B.; Herr, Joel L.

1992-01-01

Ion focusing by a biased pinhole is studied numerically. Laplace's equation is solved in 3-D for cylindrical symmetry on a constant grid to determine the potential field produced by a biased pinhole in a dielectric material. Focusing factors are studied for ions of uniform incident velocity with a 3-D Maxwellian distribution superimposed. Ion currents to the pinhole are found by particle tracking. The focusing factor of positive ions as a function of initial velocity, temperature, injection radius, and hole size is reported. For a typical Space Station Freedom environment (oxygen ions having a 4.5 eV ram energy, 0.1 eV temperature, and a -140 V biased pinhole), a focusing factor of 13.35 is found for a 1.5 mm radius pinhole.

Leucine stimulates protein synthesis in skeletal muscle of neonatal pigs by enhancing mTORC1 activation.

PubMed

Suryawan, Agus; Jeyapalan, Asumthia S; Orellana, Renan A; Wilson, Fiona A; Nguyen, Hanh V; Davis, Teresa A

2008-10-01

Skeletal muscle in the neonate grows at a rapid rate due in part to an enhanced sensitivity to the postprandial rise in amino acids, particularly leucine. To elucidate the molecular mechanism by which leucine stimulates protein synthesis in neonatal muscle, overnight-fasted 7-day-old piglets were treated with rapamycin [an inhibitor of mammalian target of rapamycin (mTOR) complex (mTORC)1] for 1 h and then infused with leucine for 1 h. Fractional rates of protein synthesis and activation of signaling components that lead to mRNA translation were determined in skeletal muscle. Rapamycin completely blocked leucine-induced muscle protein synthesis. Rapamycin markedly reduced raptor-mTOR association, an indicator of mTORC1 activation. Rapamycin blocked the leucine-induced phosphorylation of mTOR, S6 kinase 1 (S6K1), and eukaryotic initiation factor (eIF)4E-binding protein-1 (4E-BP1) and formation of the eIF4E.eIF4G complex and increased eIF4E.4E-BP1 complex abundance. Rapamycin had no effect on the association of mTOR with rictor, a crucial component for mTORC2 activation, or G protein beta-subunit-like protein (GbetaL), a component of mTORC1 and mTORC2. Neither leucine nor rapamycin affected the phosphorylation of AMP-activated protein kinase (AMPK), PKB, or tuberous sclerosis complex (TSC)2, signaling components that reside upstream of mTOR. Eukaryotic elongation factor (eEF)2 phosphorylation was not affected by leucine or rapamycin, although current dogma indicates that eEF2 phosphorylation is mTOR dependent. Together, these in vivo data suggest that leucine stimulates muscle protein synthesis in neonates by enhancing mTORC1 activation and its downstream effectors.

The antidepressant sertraline inhibits translation initiation by curtailing mammalian target of rapamycin signaling.

PubMed

Lin, Chen-Ju; Robert, Francis; Sukarieh, Rami; Michnick, Stephen; Pelletier, Jerry

2010-04-15

Sertraline, a selective serotonin reuptake inhibitor, is a widely used antidepressant agent. Here, we show that sertraline also exhibits antiproliferative activity. Exposure to sertraline leads to a concentration-dependent decrease in protein synthesis. Moreover, polysome profile analysis of sertraline-treated cells shows a reduction in polysome content and a concomitant increase in 80S ribosomes. The inhibition in translation caused by sertraline is associated with decreased levels of the eukaryotic initiation factor (eIF) 4F complex, altered localization of eIF4E, and increased eIF2alpha phosphorylation. The latter event leads to increased REDD1 expression, which in turn impinges on the mammalian target of rapamycin (mTOR) pathway by affecting TSC1/2 signaling. Sertraline also independently targets the mTOR signaling pathway downstream of Rheb. In the Emu-myc murine lymphoma model where carcinogenesis is driven by phosphatase and tensin homologue (PTEN) inactivation, sertraline is able to enhance chemosensitivity to doxorubicin. Our results indicate that sertraline exerts antiproliferative activity by targeting the mTOR signaling pathway in a REDD1-dependent manner. (c) 2010 AACR.

Mitotic MELK-eIF4B signaling controls protein synthesis and tumor cell survival

PubMed Central

Wang, Yubao; Begley, Michael; Li, Qing; Huang, Hai-Tsang; Lako, Ana; Eck, Michael J.; Gray, Nathanael S.; Mitchison, Timothy J.; Cantley, Lewis C.; Zhao, Jean J.

2016-01-01

The protein kinase maternal and embryonic leucine zipper kinase (MELK) is critical for mitotic progression of cancer cells; however, its mechanisms of action remain largely unknown. By combined approaches of immunoprecipitation/mass spectrometry and peptide library profiling, we identified the eukaryotic translation initiation factor 4B (eIF4B) as a MELK-interacting protein during mitosis and a bona fide substrate of MELK. MELK phosphorylates eIF4B at Ser406, a modification found to be most robust in the mitotic phase of the cell cycle. We further show that the MELK–eIF4B signaling axis regulates protein synthesis during mitosis. Specifically, synthesis of myeloid cell leukemia 1 (MCL1), an antiapoptotic protein known to play a role in cancer cell survival during cell division, depends on the function of MELK-elF4B. Inactivation of MELK or eIF4B results in reduced protein synthesis of MCL1, which, in turn, induces apoptotic cell death of cancer cells. Our study thus defines a MELK–eIF4B signaling axis that regulates protein synthesis during mitosis, and consequently influences cancer cell survival. PMID:27528663

Combination therapy of 15-epi-lipoxin A4 with antibiotics protects mice from Escherichia coli-induced sepsis*.

PubMed

Ueda, Tomomi; Fukunaga, Koichi; Seki, Hiroyuki; Miyata, Jun; Arita, Makoto; Miyasho, Taku; Obata, Toru; Asano, Koichiro; Betsuyaku, Tomoko; Takeda, Junzo

2014-04-01

Inflammation occurs along with infection during sepsis. 15-Epi-lipoxin A4 has protective and resolving effects in experimental models of infection. In this study, we examined the effects of 15-epi-lipoxin A4 combined with antibiotics on Escherichia coli-induced peritonitis. Prospective experimental study. University research laboratory. Male C57BL/6 mice. Mice were injected with E. coli to induce peritonitis and were given either 15-epi-lipoxin A4 (1 μg/mouse) or placebo (saline) with antibiotics (ceftazidime). The effects of 15-epi-lipoxin A4 on peritoneal cell populations, bacterial burden, and cytokine production were assessed. Survival rates were observed for up to 7 days. In addition, we examined the effects of 15-epi-lipoxin A4 on peritoneal macrophages stimulated with lipopolysaccharide, CpG DNA, or live E. coli. Treatment with 15-epi-lipoxin A4 significantly reduced the number of neutrophils in the peritoneum, inhibited production of cytokines and chemokines, and decreased bacterial load in the serum. Combined treatment of 15-epi-lipoxin A4 with antibiotics significantly improved survival in E. coli-infected mice. 15-Epi-lipoxin A4 also attenuated the production of interleukin-6 and tumor necrosis factor-α by lipopolysaccharide- or CpG DNA-stimulated peritoneal macrophages. Furthermore, 15-epi-lipoxin A4 combined with antibiotics synergistically reduced the production of interleukin-6 and tumor necrosis factor-α by peritoneal macrophages stimulated with live E. coli. 15-Epi-lipoxin A4 combined with antibiotics attenuated systemic inflammation, inhibited bacteria dissemination, and improved survival in E. coli-infected mice. The reduced production of interleukin-6 and tumor necrosis factor-α by peritoneal macrophages suggested that 15-epi-lipoxin A4 blocked the initial proinflammatory response. Taken together, these data suggested that 15-epi-lipoxin A4 combined with antibiotics was beneficial in regulating the proinflammatory response in sepsis without exacerbating infection.

Effect of electroacupuncture on the expression of mTOR and eIF4E in hippocampus of rats with vascular dementia.

PubMed

Zhu, Yanzhen; Zeng, Yanjun; Wang, Xuan; Ye, Xiaobao

2013-07-01

Clinically, electroacupuncture is proved to be an effective therapy for vascular dementia; however, their mechanisms remain uncertain. The aim of the current study was to investigate the mechanism of electroacupuncture therapy for vascular dementia. One month after a vascular dementia animal model was established by bilateral occlusion of common carotid arteries, electroacupuncture treatment was given at "Baihui" (DU20), "Dazhui" (DU14), and "Shenshu" (BL23). Morris water maze was used to assess the learning and memory ability of rats. Western blot assay was performed to detect the expression of mammalian target of rapamycin (mTOR) and eukaryotic translation initiation factor 4E (eIF4E) in hippocampus of rats. Morris water maze test showed that electroacupuncture improved the learning ability of vascular dementia rats. Western blot assay revealed that the expression level of mTOR and eIF4E in the electroacupuncture group and sham-operated group was higher than that in the vascular dementia group (P < 0.05). In conclusion, the decreasing expression of mTOR and eIF4E plays important roles in the pathogenesis of vascular dementia. Electroacupuncture improves learning and memory ability by up-regulating expression of mTOR and eIF4E in the hippocampus of vascular dementia rats.

Primary cutaneous perivascular epithelioid cell tumor: a clinicopathological and molecular reappraisal.

PubMed

Charli-Joseph, Yann; Saggini, Andrea; Vemula, Swapna; Weier, Jingly; Mirza, Sonia; LeBoit, Philip E

2014-12-01

Perivascular epithelioid cell tumor (PEComa) is a rare neoplasm of uncertain histogenesis with a mixed myomelanocytic immunophenotype, rarely arising in the skin (primary cutaneous PEComa [pcPEComa]). We analyzed the clinicopathological features of 8 pcPEComas, assayed for DNA copy number changes and for initiating mutations common in melanocytic neoplasms. pcPEComas were evaluated using immunohistochemistry, comparative genomic hybridization, and DNA sequencing. pcPEComas were erythematous nodules, mostly in the lower extremities of women (5/8), composed of large pale-staining epithelioid cells. The patient's age range was 26 to 67 (mean 46) years. The percentages of tumors staining positively were as follows: micro-ophthalmia-associated transcription factor, NKI/C3, bcl-1, E-cadherin, and cathepsin K (100%); HMB-45, 4E-binding protein 1, and CD68 (88%); smooth muscle actin and muscle-specific actin (40%); S100 (38%); calponin (20%); desmin (13%); and melan-A, SOX10, and keratin (0%). No chromosomal copy number changes or initiating mutations were identified. Small sample size is a limitation. pcPEComas have a different molecular signature than extracutaneous tumors and are unrelated to tuberous sclerosis. However, the common expression of 4E-binding protein 1 points to a role of the mTOR pathway in their pathogenesis. Because pcPEComas are diagnostically challenging, we propose that micro-ophthalmia-associated transcription factor, NKIC3, smooth muscle actin, desmin, bcl-1, cathepsin K, and 4E-binding protein 1 can be used when evaluating a possible pcPEComa. Copyright © 2014 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

Pharmacogenetic Inhibition of eIF4E-Dependent Mmp9 mRNA Translation Reverses Fragile X Syndrome-like Phenotypes

PubMed Central

Gkogkas, Christos G.; Khoutorsky, Arkady; Cao, Ruifeng; Jafarnejad, Seyed Mehdi; Prager-Khoutorsky, Masha; Giannakas, Nikolaos; Kaminari, Archontia; Fragkouli, Apostolia; Nader, Karim; Price, Theodore J.; Konicek, Bruce W.; Graff, Jeremy R.; Tzinia, Athina K.; Lacaille, Jean-Claude; Sonenberg, Nahum

2015-01-01

SUMMARY Fragile X syndrome (FXS) is the leading genetic cause of autism. Mutations in Fmr1 (fragile X mental retardation 1 gene) engender exaggerated translation resulting in dendritic spine dysmorphogenesis, synaptic plasticity alterations, and behavioral deficits in mice, which are reminiscent of FXS pheno-types. Using postmortem brains from FXS patients and Fmr1 knockout mice (Fmr1 −/y), we show that phosphorylation of the mRNA 5′ cap binding protein, eukaryotic initiation factor 4E (eIF4E), is elevated concomitant with increased expression of matrix metalloproteinase 9 (MMP-9) protein. Genetic or pharmacological reduction of eIF4E phosphorylation rescued core behavioral deficits, synaptic plasticity alterations, and dendritic spine morphology defects via reducing exaggerated translation of Mmp9 mRNA in Fmr1 −/y mice, whereas MMP-9 overexpression produced several FXS-like phenotypes. These results uncover a mechanism of regulation of synaptic function by translational control of Mmp-9 in FXS, which opens the possibility of new treatment avenues for the diverse neurological and psychiatric aspects of FXS. PMID:25466251

Electronic cigarette use and smoking initiation among youth: a longitudinal cohort study.

PubMed

Hammond, David; Reid, Jessica L; Cole, Adam G; Leatherdale, Scott T

2017-10-30

The influence of e-cigarette use on smoking initiation is a highly controversial issue, with limited longitudinal data available for examining temporal associations. We examined e-cigarette use and its association with cigarette-smoking initiation at 1-year follow-up within a large cohort of Canadian secondary school students. We analyzed data from students in grades 9-12 who participated in 2 waves of COMPASS, a cohort study of purposefully sampled secondary schools in Ontario and Alberta, Canada, at baseline (2013/14) and 1-year follow-up (2014/15). We assessed cigarette smoking and e-cigarette use at baseline and follow-up using self-completed surveys. We used generalized linear mixed-effects models to examine correlates of past 30-day e-cigarette use at baseline and smoking initiation between waves within the longitudinal sample. Past 30-day e-cigarette use increased from 2013/14 to 2014/15 (7.2% v. 9.7%, p < 0.001), whereas past 30-day cigarette smoking decreased slightly (11.4% v. 10.8%, p = 0.02). Among the 44 163 students evaluated at baseline, past 30-day e-cigarette use was strongly associated with smoking status and smoking susceptibility. In the longitudinal sample ( n = 19 130), past 30-day use of e-cigarettes at baseline was associated with initiation of smoking a whole cigarette (adjusted odds ratio [OR] 2.12, 95% confidence interval [CI] 1.68-2.66) and with initiation of daily smoking (adjusted OR 1.79, 95% CI 1.41-2.28) at follow-up. E-cigarette use was strongly associated with cigarette smoking behaviour, including smoking initiation at follow-up. The causal nature of this association remains unclear, because common factors underlying the use of both e-cigarettes and conventional cigarettes may also account for the temporal order of initiation. © 2017 Joule Inc. or its licensors.

Association Between Initial Use of e-Cigarettes and Subsequent Cigarette Smoking Among Adolescents and Young Adults: A Systematic Review and Meta-analysis.

PubMed

Soneji, Samir; Barrington-Trimis, Jessica L; Wills, Thomas A; Leventhal, Adam M; Unger, Jennifer B; Gibson, Laura A; Yang, JaeWon; Primack, Brian A; Andrews, Judy A; Miech, Richard A; Spindle, Tory R; Dick, Danielle M; Eissenberg, Thomas; Hornik, Robert C; Dang, Rui; Sargent, James D

2017-08-01

The public health implications of e-cigarettes depend, in part, on whether e-cigarette use affects the risk of cigarette smoking. To perform a systematic review and meta-analysis of longitudinal studies that assessed initial use of e-cigarettes and subsequent cigarette smoking. PubMed, EMBASE, Cochrane Library, Web of Science, the 2016 Society for Research on Nicotine and Tobacco 22nd Annual Meeting abstracts, the 2016 Society of Behavioral Medicine 37th Annual Meeting & Scientific Sessions abstracts, and the 2016 National Institutes of Health Tobacco Regulatory Science Program Conference were searched between February 7 and February 17, 2017. The search included indexed terms and text words to capture concepts associated with e-cigarettes and traditional cigarettes in articles published from database inception to the date of the search. Longitudinal studies reporting odds ratios for cigarette smoking initiation associated with ever use of e-cigarettes or past 30-day cigarette smoking associated with past 30-day e-cigarette use. Searches yielded 6959 unique studies, of which 9 met inclusion criteria (comprising 17 389 adolescents and young adults). Study quality and risk of bias were assessed using the Newcastle-Ottawa Scale and the Risk of Bias in Non-randomized Studies of Interventions tool, respectively. Data and estimates were pooled using random-effects meta-analysis. Among baseline never cigarette smokers, cigarette smoking initiation between baseline and follow-up. Among baseline non-past 30-day cigarette smokers who were past 30-day e-cigarette users, past 30-day cigarette smoking at follow-up. Among 17 389 adolescents and young adults, the ages ranged between 14 and 30 years at baseline, and 56.0% were female. The pooled probabilities of cigarette smoking initiation were 30.4% for baseline ever e-cigarette users and 7.9% for baseline never e-cigarette users. The pooled probabilities of past 30-day cigarette smoking at follow-up were 21.5% for baseline past 30-day e-cigarette users and 4.6% for baseline non-past 30-day e-cigarette users. Adjusting for known demographic, psychosocial, and behavioral risk factors for cigarette smoking, the pooled odds ratio for subsequent cigarette smoking initiation was 3.62 (95% CI, 2.42-5.41) for ever vs never e-cigarette users, and the pooled odds ratio for past 30-day cigarette smoking at follow-up was 4.28 (95% CI, 2.52-7.27) for past 30-day e-cigarette vs non-past 30-day e-cigarette users at baseline. A moderate level of heterogeneity was observed among studies (I2 = 60.1%). e-Cigarette use was associated with greater risk for subsequent cigarette smoking initiation and past 30-day cigarette smoking. Strong e-cigarette regulation could potentially curb use among youth and possibly limit the future population-level burden of cigarette smoking.

Analysis of eIF4E and 4EBP1 mRNAs in head and neck cancer.

PubMed

Sunavala-Dossabhoy, Gulshan; Palaniyandi, Senthilnathan; Clark, Cheryl; Nathan, Cherie-Ann O; Abreo, Fleurette W; Caldito, Gloria

2011-10-01

The eukaryotic translation initiation factor 4E (eIF4E) in conjunction with its binding protein, 4EBP1, regulates the translation of cap-dependent mRNAs. An aberrant increase in eIF4E shifts the balance in favor of translation of transcripts that promote cell proliferation and malignancy. eIF4E protein is commonly elevated in head and neck squamous cell carcinomas (HNSCC), and its overexpression is associated with increased recurrence. An underlying mechanism for eIF4E overexpression is gene amplification, and we wanted to determine whether eIF4E mRNA could serve as a prognostic maker of HNSCC. Tumor specimens from 26 HNSCC patients and oral tissues from 17 control subjects were examined for eIF4E and 4EBP1 by semiquantitative RT-PCR and correlated with clinical and pathologic findings. Unlike eIF4E mRNA alone, expression of eIF4E relative to 4EBP1 was a more precise predictor of HNSCC and its progression (P < .01, Wilcoxon rank sum test). Eight of 26 patients (31%) had elevated eIF4E:4EBP1 (4E:4EBP1; >25), and 7 of these (87.5%) had recurrence. Alternately, from 18 patients with low 4E:4EBP1 (<25; 69%), only 5 patients had recurrence (30.1%). To determine the probability of no recurrence, Kaplan-Meier analysis showed significantly poor disease-free survival in patients with elevated 4E:4EBP1 than those with low ratios (P < .01, log rank test). Elevated 4E:4EBP1 significantly correlated with increased disease recurrence. Because 4EBP1 modulates eIF4E activity, our results highlight the importance of incorporating a joint analysis of eIF4E and 4EBP1 mRNAs in HNSCC patient care decisions. Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.

Leucine stimulates protein synthesis in skeletal muscle of neonatal pigs by enhancing mTORC1 activation

PubMed Central

Suryawan, Agus; Jeyapalan, Asumthia S.; Orellana, Renan A.; Wilson, Fiona A.; Nguyen, Hanh V.; Davis, Teresa A.

2008-01-01

Skeletal muscle in the neonate grows at a rapid rate due in part to an enhanced sensitivity to the postprandial rise in amino acids, particularly leucine. To elucidate the molecular mechanism by which leucine stimulates protein synthesis in neonatal muscle, overnight-fasted 7-day-old piglets were treated with rapamycin [an inhibitor of mammalian target of rapamycin (mTOR) complex (mTORC)1] for 1 h and then infused with leucine for 1 h. Fractional rates of protein synthesis and activation of signaling components that lead to mRNA translation were determined in skeletal muscle. Rapamycin completely blocked leucine-induced muscle protein synthesis. Rapamycin markedly reduced raptor-mTOR association, an indicator of mTORC1 activation. Rapamycin blocked the leucine-induced phosphorylation of mTOR, S6 kinase 1 (S6K1), and eukaryotic initiation factor (eIF)4E-binding protein-1 (4E-BP1) and formation of the eIF4E·eIF4G complex and increased eIF4E·4E-BP1 complex abundance. Rapamycin had no effect on the association of mTOR with rictor, a crucial component for mTORC2 activation, or G protein β-subunit-like protein (GβL), a component of mTORC1 and mTORC2. Neither leucine nor rapamycin affected the phosphorylation of AMP-activated protein kinase (AMPK), PKB, or tuberous sclerosis complex (TSC)2, signaling components that reside upstream of mTOR. Eukaryotic elongation factor (eEF)2 phosphorylation was not affected by leucine or rapamycin, although current dogma indicates that eEF2 phosphorylation is mTOR dependent. Together, these in vivo data suggest that leucine stimulates muscle protein synthesis in neonates by enhancing mTORC1 activation and its downstream effectors. PMID:18682538

Loss of the endothelial glycocalyx is associated with increased E-selectin mediated adhesion of lung tumour cells to the brain microvascular endothelium.

PubMed

Rai, Srijana; Nejadhamzeeigilani, Zaynab; Gutowski, Nicholas J; Whatmore, Jacqueline L

2015-09-25

Arrest of metastasising lung cancer cells to the brain microvasculature maybe mediated by interactions between ligands on circulating tumour cells and endothelial E-selectin adhesion molecules; a process likely to be regulated by the endothelial glycocalyx. Using human cerebral microvascular endothelial cells and non-small cell lung cancer (NSCLC) cell lines, we describe how factors secreted by NSCLC cells i.e. cystatin C, cathepsin L, insulin-like growth factor-binding protein 7 (IGFBP7), vascular endothelial growth factor (VEGF) and tumour necrosis factor-alpha (TNF-α), damage the glycocalyx and enhance initial contacts between lung tumour and cerebral endothelial cells. Endothelial cells were treated with tumour secreted-proteins or lung tumour conditioned medium (CM). Surface levels of E-selectin were quantified by ELISA. Adhesion of A549 and SK-MES-1 cells was examined under flow conditions (1 dyne/cm(2)). Alterations in the endothelial glycocalyx were quantified by binding of fluorescein isothiocyanate-linked wheat germ agglutinin (WGA-FITC). A549 and SK-MES-1 CM and secreted-proteins significantly enhanced endothelial surface E-selectin levels after 30 min and 4 h and tumour cell adhesion after 30 min, 4 and 24 h. Both coincided with significant glycocalyx degradation; A549 and SK-MES-1 CM removing 55 ± 12 % and 58 ± 18.7 % of WGA-FITC binding, respectively. Inhibition of E-selectin binding by monoclonal anti-E-selectin antibody completely attenuated tumour cell adhesion. These data suggest that metastasising lung cancer cells facilitate their own adhesion to the brain endothelium by secreting factors that damage the endothelial glycocalyx, resulting in exposure of the previously shielded adhesion molecules and engagement of the E-selectin-mediated adhesion axis.

Minimum requirements for the function of eukaryotic translation initiation factor 2.

PubMed Central

Erickson, F L; Nika, J; Rippel, S; Hannig, E M

2001-01-01

Eukaryotic translation initiation factor 2 (eIF2) is a G protein heterotrimer required for GTP-dependent delivery of initiator tRNA to the ribosome. eIF2B, the nucleotide exchange factor for eIF2, is a heteropentamer that, in yeast, is encoded by four essential genes and one nonessential gene. We found that increased levels of wild-type eIF2, in the presence of sufficient levels of initiator tRNA, overcome the requirement for eIF2B in vivo. Consistent with bypassing eIF2B, these conditions also suppress the lethal effect of overexpressing the mammalian tumor suppressor PKR, an eIF2alpha kinase. The effects described are further enhanced in the presence of a mutation in the G protein (gamma) subunit of eIF2, gcd11-K250R, which mimics the function of eIF2B in vitro. Interestingly, the same conditions that bypass eIF2B also overcome the requirement for the normally essential eIF2alpha structural gene (SUI2). Our results suggest that the eIF2betagamma complex is capable of carrying out the essential function(s) of eIF2 in the absence of eIF2alpha and eIF2B and are consistent with the idea that the latter function primarily to regulate the level of eIF2.GTP.Met-tRNA(i)(Met) ternary complexes in vivo. PMID:11333223

Identification and Characterization of Functionally Critical, Conserved Motifs in the Internal Repeats and N-terminal Domain of Yeast Translation Initiation Factor 4B (yeIF4B)*

PubMed Central

Zhou, Fujun; Walker, Sarah E.; Mitchell, Sarah F.; Lorsch, Jon R.; Hinnebusch, Alan G.

2014-01-01

eIF4B has been implicated in attachment of the 43 S preinitiation complex (PIC) to mRNAs and scanning to the start codon. We recently determined that the internal seven repeats (of ∼26 amino acids each) of Saccharomyces cerevisiae eIF4B (yeIF4B) compose the region most critically required to enhance mRNA recruitment by 43 S PICs in vitro and stimulate general translation initiation in yeast. Moreover, although the N-terminal domain (NTD) of yeIF4B contributes to these activities, the RNA recognition motif is dispensable. We have now determined that only two of the seven internal repeats are sufficient for wild-type (WT) yeIF4B function in vivo when all other domains are intact. However, three or more repeats are needed in the absence of the NTD or when the functions of eIF4F components are compromised. We corroborated these observations in the reconstituted system by demonstrating that yeIF4B variants with only one or two repeats display substantial activity in promoting mRNA recruitment by the PIC, whereas additional repeats are required at lower levels of eIF4A or when the NTD is missing. These findings indicate functional overlap among the 7-repeats and NTD domains of yeIF4B and eIF4A in mRNA recruitment. Interestingly, only three highly conserved positions in the 26-amino acid repeat are essential for function in vitro and in vivo. Finally, we identified conserved motifs in the NTD and demonstrate functional overlap of two such motifs. These results provide a comprehensive description of the critical sequence elements in yeIF4B that support eIF4F function in mRNA recruitment by the PIC. PMID:24285537

Lack of neural compensatory mechanisms of BDNF val66met met carriers and APOE E4 carriers in healthy aging, mild cognitive impairment, and Alzheimer's disease.

PubMed

Gomar, Jesus J; Conejero-Goldberg, Concepcion; Huey, Edward D; Davies, Peter; Goldberg, Terry E

2016-03-01

Compromises in compensatory neurobiologic mechanisms due to aging and/or genetic factors (i.e., APOE gene) may influence brain-derived neurotrophic factor (BDNF) val66met polymorphism effects on temporal lobe morphometry and memory performance. We studied 2 cohorts from Alzheimer's Disease Neuroimaging Initiative: 175 healthy subjects and 222 with prodromal and established Alzheimer's disease. Yearly structural magnetic resonance imaging and cognitive performance assessments were carried out over 3 years of follow-up. Both cohorts had similar BDNF Val/Val and Met allele carriers' (including both Val/Met and Met/Met individuals) distribution. In healthy subjects, a significant trend for thinner posterior cingulate and precuneus cortices was detected in Met carriers compared to Val homozygotes in APOE E4 carriers, with large and medium effect sizes, respectively. The mild cognitive impairment/Alzheimer's disease cohort showed a longitudinal decline in entorhinal thickness in BDNF Met carriers compared to Val/Val in APOE E4 carriers, with effect sizes ranging from medium to large. In addition, an effect of BDNF genotype was found in APOE E4 carriers for episodic memory (logical memory and ADAS-Cog) and semantic fluency measures, with Met carriers performing worse in all cases. These findings suggest a lack of compensatory mechanisms in BDNF Met carriers and APOE E4 carriers in healthy and pathological aging. Copyright © 2016 Elsevier Inc. All rights reserved.

Low-Intensity Extracorporeal Shock Wave Therapy Enhances Brain-Derived Neurotrophic Factor Expression through PERK/ATF4 Signaling Pathway.

PubMed

Wang, Bohan; Ning, Hongxiu; Reed-Maldonado, Amanda B; Zhou, Jun; Ruan, Yajun; Zhou, Tie; Wang, Hsun Shuan; Oh, Byung Seok; Banie, Lia; Lin, Guiting; Lue, Tom F

2017-02-16

Low-intensity extracorporeal shock wave therapy (Li-ESWT) is used in the treatment of erectile dysfunction, but its mechanisms are not well understood. Previously, we found that Li-ESWT increased the expression of brain-derived neurotrophic factor (BDNF). Here we assessed the underlying signaling pathways in Schwann cells in vitro and in penis tissue in vivo after nerve injury. The result indicated that BDNF were significantly increased by the Li-ESWT after nerve injury, as well as the expression of BDNF in Schwann cells (SCs, RT4-D6P2T) in vitro. Li-ESWT activated the protein kinase RNA-like endoplasmic reticulum (ER) kinase (PERK) pathway by increasing the phosphorylation levels of PERK and eukaryotic initiation factor 2a (eIF2α), and enhanced activating transcription factor 4 (ATF4) in an energy-dependent manner. In addition, GSK2656157-an inhibitor of PERK-effectively inhibited the effect of Li-ESWT on the phosphorylation of PERK, eIF2α, and the expression of ATF4. Furthermore, silencing ATF4 dramatically attenuated the effect of Li-ESWT on the expression of BDNF, but had no effect on hypoxia-inducible factor (HIF)1α or glial cell-derived neurotrophic factor (GDNF) in Schwann cells. In conclusion, our findings shed new light on the underlying mechanisms by which Li-ESWT may stimulate the expression of BDNF through activation of PERK/ATF4 signaling pathway. This information may help to refine the use of Li-ESWT to further improve its clinical efficacy.

Low-Intensity Extracorporeal Shock Wave Therapy Enhances Brain-Derived Neurotrophic Factor Expression through PERK/ATF4 Signaling Pathway

PubMed Central

Wang, Bohan; Ning, Hongxiu; Reed-Maldonado, Amanda B.; Zhou, Jun; Ruan, Yajun; Zhou, Tie; Wang, Hsun Shuan; Oh, Byung Seok; Banie, Lia; Lin, Guiting; Lue, Tom F.

2017-01-01

Low-intensity extracorporeal shock wave therapy (Li-ESWT) is used in the treatment of erectile dysfunction, but its mechanisms are not well understood. Previously, we found that Li-ESWT increased the expression of brain-derived neurotrophic factor (BDNF). Here we assessed the underlying signaling pathways in Schwann cells in vitro and in penis tissue in vivo after nerve injury. The result indicated that BDNF were significantly increased by the Li-ESWT after nerve injury, as well as the expression of BDNF in Schwann cells (SCs, RT4-D6P2T) in vitro. Li-ESWT activated the protein kinase RNA-like endoplasmic reticulum (ER) kinase (PERK) pathway by increasing the phosphorylation levels of PERK and eukaryotic initiation factor 2a (eIF2α), and enhanced activating transcription factor 4 (ATF4) in an energy-dependent manner. In addition, GSK2656157—an inhibitor of PERK—effectively inhibited the effect of Li-ESWT on the phosphorylation of PERK, eIF2α, and the expression of ATF4. Furthermore, silencing ATF4 dramatically attenuated the effect of Li-ESWT on the expression of BDNF, but had no effect on hypoxia-inducible factor (HIF)1α or glial cell-derived neurotrophic factor (GDNF) in Schwann cells. In conclusion, our findings shed new light on the underlying mechanisms by which Li-ESWT may stimulate the expression of BDNF through activation of PERK/ATF4 signaling pathway. This information may help to refine the use of Li-ESWT to further improve its clinical efficacy. PMID:28212323

N-body simulations of star clusters

NASA Astrophysics Data System (ADS)

Engle, Kimberly Anne

1999-10-01

We investigate the structure and evolution of underfilling (i.e. non-Roche-lobe-filling) King model globular star clusters using N-body simulations. We model clusters with various underfilling factors and mass distributions to determine their evolutionary tracks and lifetimes. These models include a self-consistent galactic tidal field, mass loss due to stellar evolution, ejection, and evaporation, and binary evolution. We find that a star cluster that initially does not fill its Roche lobe can live many times longer than one that does initially fill its Roche lobe. After a few relaxation times, the cluster expands to fill its Roche lobe. We also find that the choice of initial mass function significantly affects the lifetime of the cluster. These simulations were performed on the GRAPE-4 (GRAvity PipE) special-purpose hardware with the stellar dynamics package ``Starlab.'' The GRAPE-4 system is a massively-parallel computer designed to calculate the force (and its first time derivative) due to N particles. Starlab's integrator ``kira'' employs a 4th- order Hermite scheme with hierarchical (block) time steps to evolve the stellar system. We discuss, in some detail, the design of the GRAPE-4 system and the manner in which the Hermite integration scheme with block time steps is implemented in the hardware.

Autonomy and structure can enhance motivation of volunteers in sport organizations.

PubMed

Hsu, Wei Ting; Wu, Kou Hsien; Wang, Yi Ching; Hsiao, Chia Huei; Wu, Hui Chin

2013-12-01

The goal was better understanding of the motivational factors of volunteers in non-profit sport organizations. The roles of two factors provided by supervisors to their subordinates were examined: autonomy support, i.e., the encouragement of self-initiation and emphasis on choice rather than control, and structure, i.e., the introduction of order, definite procedures, and rules. 489 sport volunteers (289 men, 200 women; M age = 31.2 yr., SD = 7.4) were administered questionnaires assessing their perceived autonomy support, structure, and motivation. Regression analysis indicated that perceived autonomy support predicted motivation. Structure also mediated the effect of perceived autonomy support on motivation. Supervisors of sport organizations should provide adequate structure for their volunteers.

Silencing c-Myc translation as a therapeutic strategy through targeting PI3Kδ and CK1ε in hematological malignancies.

PubMed

Deng, Changchun; Lipstein, Mark R; Scotto, Luigi; Jirau Serrano, Xavier O; Mangone, Michael A; Li, Shirong; Vendome, Jeremie; Hao, Yun; Xu, Xiaoming; Deng, Shi-Xian; Realubit, Ronald B; Tatonetti, Nicholas P; Karan, Charles; Lentzsch, Suzanne; Fruman, David A; Honig, Barry; Landry, Donald W; O'Connor, Owen A

2017-01-05

Phosphoinositide 3-kinase (PI3K) and the proteasome pathway are both involved in activating the mechanistic target of rapamycin (mTOR). Because mTOR signaling is required for initiation of messenger RNA translation, we hypothesized that cotargeting the PI3K and proteasome pathways might synergistically inhibit translation of c-Myc. We found that a novel PI3K δ isoform inhibitor TGR-1202, but not the approved PI3Kδ inhibitor idelalisib, was highly synergistic with the proteasome inhibitor carfilzomib in lymphoma, leukemia, and myeloma cell lines and primary lymphoma and leukemia cells. TGR-1202 and carfilzomib (TC) synergistically inhibited phosphorylation of the eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1), leading to suppression of c-Myc translation and silencing of c-Myc-dependent transcription. The synergistic cytotoxicity of TC was rescued by overexpression of eIF4E or c-Myc. TGR-1202, but not other PI3Kδ inhibitors, inhibited casein kinase-1 ε (CK1ε). Targeting CK1ε using a selective chemical inhibitor or short hairpin RNA complements the effects of idelalisib, as a single agent or in combination with carfilzomib, in repressing phosphorylation of 4E-BP1 and the protein level of c-Myc. These results suggest that TGR-1202 is a dual PI3Kδ/CK1ε inhibitor, which may in part explain the clinical activity of TGR-1202 in aggressive lymphoma not found with idelalisib. Targeting CK1ε should become an integral part of therapeutic strategies targeting translation of oncogenes such as c-Myc. © 2017 by The American Society of Hematology.

The influence of viral coding sequences on pestivirus IRES activity reveals further parallels with translation initiation in prokaryotes.

PubMed Central

Fletcher, Simon P; Ali, Iraj K; Kaminski, Ann; Digard, Paul; Jackson, Richard J

2002-01-01

Classical swine fever virus (CSFV) is a member of the pestivirus family, which shares many features in common with hepatitis C virus (HCV). It is shown here that CSFV has an exceptionally efficient cis-acting internal ribosome entry segment (IRES), which, like that of HCV, is strongly influenced by the sequences immediately downstream of the initiation codon, and is optimal with viral coding sequences in this position. Constructs that retained 17 or more codons of viral coding sequence exhibited full IRES activity, but with only 12 codons, activity was approximately 66% of maximum in vitro (though close to maximum in transfected BHK cells), whereas with just 3 codons or fewer, the activity was only approximately 15% of maximum. The minimal coding region elements required for high activity were exchanged between HCV and CSFV. Although maximum activity was observed in each case with the homologous combination of coding region and 5' UTR, the heterologous combinations were sufficiently active to rule out a highly specific functional interplay between the 5' UTR and coding sequences. On the other hand, inversion of the coding sequences resulted in low IRES activity, particularly with the HCV coding sequences. RNA structure probing showed that the efficiency of internal initiation of these chimeric constructs correlated most closely with the degree of single-strandedness of the region around and immediately downstream of the initiation codon. The low activity IRESs could not be rescued by addition of supplementary eIF4A (the initiation factor with ATP-dependent RNA helicase activity). The extreme sensitivity to secondary structure around the initiation codon is likely to be due to the fact that the eIF4F complex (which has eIF4A as one of its subunits) is not required for and does not participate in initiation on these IRESs. PMID:12515388

Host control of plasmid replication: requirement for the sigma factor sigma 32 in transcription of mini-F replication initiator gene.

PubMed Central

Wada, C; Imai, M; Yura, T

1987-01-01

Replication of F factor or mini-F plasmid is strongly inhibited in the rpoH (htpR) mutants of Escherichia coli deficient in the sigma factor (sigma 32) known to be required for heat shock gene expression. Transcription of the mini-F repE gene encoding a replication initiator protein (E protein) was examined by operon fusion and by direct determination of repE mRNA. The synthesis rate and the level of repE mRNA were found to increase transiently upon temperature upshift (30 degrees C to 42 degrees C) in wild-type cells but to decrease rapidly in the rpoH mutants. Thus sigma 32 appeared to be directly involved in transcription of repE whose product, E protein, in turn activates DNA replication from the mini-F ori2 region. This scheme of host-controlled plasmid replication is further supported by the analysis of transcription in vitro: RNA synthesis can be initiated from the repE promoter by a minor form of RNA polymerase containing sigma 32 but not by the major polymerase containing the normal sigma factor sigma 70. The sigma 32-mediated transcription from the repE promoter is strongly inhibited by the E protein. We conclude that transcription of the mini-F repE gene is mediated by the host transcription factor sigma 32 and is negatively controlled by its own product. Images PMID:2447584

Covalent Chemical 5'-Functionalization of RNA with Diazo Reagents.

PubMed

Gampe, Christian M; Hollis-Symynkywicz, Micah; Zécri, Frédéric

2016-08-22

Functionalization of RNA at the 5'-terminus is important for analytical and therapeutic purposes. Currently, these RNAs are synthesized de novo starting with a chemically functionalized 5'-nucleotide, which is incorporated into RNA using chemical synthesis or biochemical techniques. Methods for direct chemical modification of native RNA would provide an attractive alternative but are currently underexplored. Herein, we report that diazo compounds can be used to selectively alkylate the 5'-phosphate of ribo(oligo)nucleotides to give RNA labelled through a native phosphate ester bond. We applied this method to functionalize oligonucleotides with biotin and an orthosteric inhibitor of the eukaryotic initiation factor 4E (eIF4E), an enzyme involved in mRNA recognition. The modified RNA binds to eIF4E, demonstrating the utility of this labelling technique to modulate biological activity of RNA. This method complements existing techniques and may be used to chemically introduce a broad range of functional handles at the 5'-end of RNA. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Generational status and social factors predicting initiation of partnered sexual activity among Latino/a youth.

PubMed

Cabral, Patricia; Wallander, Jan L; Song, Anna V; Elliott, Marc N; Tortolero, Susan R; Reisner, Sari L; Schuster, Mark A

2017-02-01

Examine the longitudinal association of generational status (first = child and parent born outside the United States; second = child born in the United States, parent born outside the United States; third = child and parent born in the United States) and parent and peer social factors considered in 5th grade with subsequent oral, vaginal, and anal intercourse initiation by 7th and 10th grade among Latino/a youth. Using data from Latino/a participants (N = 1,790) in the Healthy Passages™ study, the authors measured generational status (first = 18.4%, second = 57.3%, third-generation = 24.3%) and parental (i.e., monitoring, involvement, nurturance) and peer (i.e., friendship quality, social interaction, peer norms) influences in 5th grade and oral, vaginal, and anal intercourse initiation by 7th and 10th (retention = 89%) grade. Among girls, parental monitoring, social interaction, friendship quality, and peer norms predicted sexual initiation. Among boys, parental involvement, social interaction, and peer norms predicted sexual initiation (ps < .05). When ≥1 friend was perceived to have initiated sexual intercourse, third-generation Latinas were more than twice as likely as first- and second-generation Latinas (ps < .05) to initiate vaginal intercourse by 10th grade and almost 5 times as likely as first-generation Latinas to initiate oral intercourse by 7th grade. Among Latina youth, generational status plays a role in social influences on vaginal and oral intercourse initiation. Moreover, Latinas and Latinos differ in which social influences predict sexual intercourse initiation. Preventive efforts for Latino/a youth may need to differ by gender and generational status. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

MNK1/2 inhibition limits oncogenicity and metastasis of KIT-mutant melanoma

PubMed Central

Zhan, Yao; Guo, Jun; Yang, William; Goncalves, Christophe; Rzymski, Tomasz; Dreas, Agnieszka; Żyłkiewicz, Eliza; Mikulski, Maciej; Brzózka, Krzysztof; Golas, Aniela; Kong, Yan; Ma, Meng; Huang, Fan; Huor, Bonnie; Guo, Qianyu; da Silva, Sabrina Daniela; Torres, Jose; Cai, Yutian; Topisirovic, Ivan; Su, Jie; Bijian, Krikor; Alaoui-Jamali, Moulay A.; Huang, Sidong; Journe, Fabrice; Ghanem, Ghanem E.; Miller, Wilson H.

2017-01-01

Melanoma can be stratified into unique subtypes based on distinct pathologies. The acral/mucosal melanoma subtype is characterized by aberrant and constitutive activation of the proto-oncogene receptor tyrosine kinase C-KIT, which drives tumorigenesis. Treatment of these melanoma patients with C-KIT inhibitors has proven challenging, prompting us to investigate the downstream effectors of the C-KIT receptor. We determined that C-KIT stimulates MAP kinase–interacting serine/threonine kinases 1 and 2 (MNK1/2), which phosphorylate eukaryotic translation initiation factor 4E (eIF4E) and render it oncogenic. Depletion of MNK1/2 in melanoma cells with oncogenic C-KIT inhibited cell migration and mRNA translation of the transcriptional repressor SNAI1 and the cell cycle gene CCNE1. This suggested that blocking MNK1/2 activity may inhibit tumor progression, at least in part, by blocking translation initiation of mRNAs encoding cell migration proteins. Moreover, we developed an MNK1/2 inhibitor (SEL201), and found that SEL201-treated KIT-mutant melanoma cells had lower oncogenicity and reduced metastatic ability. Clinically, tumors from melanoma patients harboring KIT mutations displayed a marked increase in MNK1 and phospho-eIF4E. Thus, our studies indicate that blocking MNK1/2 exerts potent antimelanoma effects and support blocking MNK1/2 as a potential strategy to treat patients positive for KIT mutations. PMID:29035277

MNK1/2 inhibition limits oncogenicity and metastasis of KIT-mutant melanoma.

PubMed

Zhan, Yao; Guo, Jun; Yang, William; Goncalves, Christophe; Rzymski, Tomasz; Dreas, Agnieszka; Żyłkiewicz, Eliza; Mikulski, Maciej; Brzózka, Krzysztof; Golas, Aniela; Kong, Yan; Ma, Meng; Huang, Fan; Huor, Bonnie; Guo, Qianyu; da Silva, Sabrina Daniela; Torres, Jose; Cai, Yutian; Topisirovic, Ivan; Su, Jie; Bijian, Krikor; Alaoui-Jamali, Moulay A; Huang, Sidong; Journe, Fabrice; Ghanem, Ghanem E; Miller, Wilson H; Del Rincón, Sonia V

2017-11-01

Melanoma can be stratified into unique subtypes based on distinct pathologies. The acral/mucosal melanoma subtype is characterized by aberrant and constitutive activation of the proto-oncogene receptor tyrosine kinase C-KIT, which drives tumorigenesis. Treatment of these melanoma patients with C-KIT inhibitors has proven challenging, prompting us to investigate the downstream effectors of the C-KIT receptor. We determined that C-KIT stimulates MAP kinase-interacting serine/threonine kinases 1 and 2 (MNK1/2), which phosphorylate eukaryotic translation initiation factor 4E (eIF4E) and render it oncogenic. Depletion of MNK1/2 in melanoma cells with oncogenic C-KIT inhibited cell migration and mRNA translation of the transcriptional repressor SNAI1 and the cell cycle gene CCNE1. This suggested that blocking MNK1/2 activity may inhibit tumor progression, at least in part, by blocking translation initiation of mRNAs encoding cell migration proteins. Moreover, we developed an MNK1/2 inhibitor (SEL201), and found that SEL201-treated KIT-mutant melanoma cells had lower oncogenicity and reduced metastatic ability. Clinically, tumors from melanoma patients harboring KIT mutations displayed a marked increase in MNK1 and phospho-eIF4E. Thus, our studies indicate that blocking MNK1/2 exerts potent antimelanoma effects and support blocking MNK1/2 as a potential strategy to treat patients positive for KIT mutations.

Stimulation of translation by human Unr requires cold shock domains 2 and 4, and correlates with poly(A) binding protein interaction.

PubMed

Ray, Swagat; Anderson, Emma C

2016-03-03

The RNA binding protein Unr, which contains five cold shock domains, has several specific roles in post-transcriptional control of gene expression. It can act as an activator or inhibitor of translation initiation, promote mRNA turnover, or stabilise mRNA. Its role depends on the mRNA and other proteins to which it binds, which includes cytoplasmic poly(A) binding protein 1 (PABP1). Since PABP1 binds to all polyadenylated mRNAs, and is involved in translation initiation by interaction with eukaryotic translation initiation factor 4G (eIF4G), we investigated whether Unr has a general role in translational control. We found that Unr strongly stimulates translation in vitro, and mutation of cold shock domains 2 or 4 inhibited its translation activity. The ability of Unr and its mutants to stimulate translation correlated with its ability to bind RNA, and to interact with PABP1. We found that Unr stimulated the binding of PABP1 to mRNA, and that Unr was required for the stable interaction of PABP1 and eIF4G in cells. siRNA-mediated knockdown of Unr reduced the overall level of cellular translation in cells, as well as that of cap-dependent and IRES-dependent reporters. These data describe a novel role for Unr in regulating cellular gene expression.

Strategy to Minimize Energetics Contamination at Military Testing/Training Ranges

DTIC Science & Technology

2005-09-01

exploding foil exploding foil initiator ) initiator will minimize the energetic material...i.e., exploding foil initiator P 𔃾 𔃾 𔃾 𔃾 4. Use an electronic S&A; i.e., high voltage driven semi-conductor bridge elements P ’ 𔃾 𔃾 𔃾 5. Use...alternatives Opportunity 1. Eliminate energetics 3. Use an electronic S&A; i.e., exploding foil initiator 1 3 3 -3 2 -6 -2 1 -2 -5 4. Use an

Predictors of youth e-cigarette use susceptibility in a U.S. nationally representative sample.

PubMed

Kwon, Elizabeth; Seo, Dong-Chul; Lin, Hsien-Chang; Chen, Zhongxue

2018-07-01

Given that nicotine is one of the most addictive substances and that adolescents who are exposed to nicotine via e-cigarettes can progress to conventional cigarette smoking, there is a need to identify youth who are susceptible to e-cigarette use and prevent them from initiating e-cigarette use. Susceptibility to e-cigarette use, defined as the absence of a firm decision not to use e-cigarettes, is a useful concept that can be used to predict e-cigarette initiation and identify youth who have high risk of initiating e-cigarettes. This study was conducted to investigate factors that affect youth susceptibility to e-cigarette use. Youth who have never smoked conventional cigarettes and who had seen or heard of e-cigarettes but never used them (N = 9853) were drawn from the Population Assessment of Tobacco and Health (PATH) Study Wave 1 youth dataset collected from 2013 to 2014. Data were analyzed using logistic regression to investigate intrapersonal and environmental determinants of youth susceptibility to e-cigarette use. Overall, 24.2% (n = 2410) of youth who have never used e-cigarettes were susceptible to e-cigarette use. Psychological problems and rebelliousness were associated with increased susceptibility. Ever use of alcohol, marijuana, and other substances and household secondhand smoke exposure were found to be risk factors. Perceptions of e-cigarettes as addictive and harmful worked as protective factors. The results revealed determinants of e-cigarette use susceptibility. Multi-level intervention approach is needed to prevent youth from being susceptible to e-cigarette initiation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Induction of cap-independent BiP (hsp-3) and Bcl-2 (ced-9) translation in response to eIF4G (IFG-1) depletion in C. elegans

PubMed Central

Morrison, J Kaitlin; Friday, Andrew J; Henderson, Melissa A; Hao, Enhui; Keiper, Brett D

2014-01-01

During apoptosis, activated caspases cleave the translation initiation factor eIF4G. This cleavage disrupts cap-dependent mRNA translation initiation within the cell. However, a specific subset of mRNAs can still be recruited for protein synthesis in a cap-independent manner by the residual initiation machinery. Many of these mRNAs, including cell death related mRNAs, contain internal ribosome entry sites (IRESes) that promote their enhanced translation during apoptosis. Still other mRNAs have little dependence on the cap recognition mechanism. The expression of the encoded proteins, both anti- and pro-apoptotic, allows for an initial period of attempted cell survival, then commitment to cell death when damage is extensive. In this study we address the translational regulation of the stress and apoptosis-related mRNAs in C. elegans: BiP (hsp-3) (hsp-4), Hif-1 (hif-1), p53 (cep-1), Bcl-2 (ced-9) and Apaf-1 (ced-4). Altered translational efficiency of these messages was observed upon depletion of cap-dependent translation and induction of apoptosis within the C. elegans gonad. Our findings suggest a physiological link between the cap-independent mechanism and the enhanced translation of hsp-3 and ced-9. This increase in the efficiency of translation may be integral to the stress response during the induction of physiological apoptosis. PMID:26779406

E-Cigarettes and Future Cigarette Use

PubMed Central

Urman, Robert; Berhane, Kiros; Unger, Jennifer B.; Cruz, Tess Boley; Pentz, Mary Ann; Samet, Jonathan M.; Leventhal, Adam M.; McConnell, Rob

2016-01-01

BACKGROUND: There has been little research examining whether e-cigarette use increases the risk of cigarette initiation among adolescents in the transition to adulthood when the sale of cigarettes becomes legal. METHODS: The Children’s Health Study is a prospectively followed cohort in Southern California. Data on e-cigarette use were collected in 11th and 12th grade (mean age = 17.4); follow-up data on tobacco product use were collected an average of 16 months later from never-smoking e-cigarette users at initial evaluation (n = 146) and from a sample of never-smoking, never e-cigarette users (n = 152) frequency matched to e-cigarette users on gender, ethnicity, and grade. RESULTS: Cigarette initiation during follow-up was reported by 40.4% of e-cigarette users (n = 59) and 10.5% of never users (n = 16). E-cigarette users had 6.17 times (95% confidence interval: 3.30–11.6) the odds of initiating cigarettes as never e-cigarette users. Results were robust to adjustment for potential confounders and in analyses restricted to never users of any combustible tobacco product. Associations were stronger in adolescents with no intention of smoking at initial evaluation. E-cigarette users were also more likely to initiate use of any combustible product (odds ratio = 4.98; 95% confidence interval: 2.37–10.4), including hookah, cigars, or pipes. CONCLUSIONS: E-cigarette use in never-smoking youth may increase risk of subsequent initiation of cigarettes and other combustible products during the transition to adulthood when the purchase of tobacco products becomes legal. Stronger associations in participants with no intention of smoking suggests that e-cigarette use was not simply a marker for individuals who would have gone on to smoke regardless of e-cigarette use. PMID:27296866

E-Cigarettes and Future Cigarette Use.

PubMed

Barrington-Trimis, Jessica L; Urman, Robert; Berhane, Kiros; Unger, Jennifer B; Cruz, Tess Boley; Pentz, Mary Ann; Samet, Jonathan M; Leventhal, Adam M; McConnell, Rob

2016-07-01

There has been little research examining whether e-cigarette use increases the risk of cigarette initiation among adolescents in the transition to adulthood when the sale of cigarettes becomes legal. The Children's Health Study is a prospectively followed cohort in Southern California. Data on e-cigarette use were collected in 11th and 12th grade (mean age = 17.4); follow-up data on tobacco product use were collected an average of 16 months later from never-smoking e-cigarette users at initial evaluation (n = 146) and from a sample of never-smoking, never e-cigarette users (n = 152) frequency matched to e-cigarette users on gender, ethnicity, and grade. Cigarette initiation during follow-up was reported by 40.4% of e-cigarette users (n = 59) and 10.5% of never users (n = 16). E-cigarette users had 6.17 times (95% confidence interval: 3.30-11.6) the odds of initiating cigarettes as never e-cigarette users. Results were robust to adjustment for potential confounders and in analyses restricted to never users of any combustible tobacco product. Associations were stronger in adolescents with no intention of smoking at initial evaluation. E-cigarette users were also more likely to initiate use of any combustible product (odds ratio = 4.98; 95% confidence interval: 2.37-10.4), including hookah, cigars, or pipes. E-cigarette use in never-smoking youth may increase risk of subsequent initiation of cigarettes and other combustible products during the transition to adulthood when the purchase of tobacco products becomes legal. Stronger associations in participants with no intention of smoking suggests that e-cigarette use was not simply a marker for individuals who would have gone on to smoke regardless of e-cigarette use. Copyright © 2016 by the American Academy of Pediatrics.

Diversity of Eukaryotic Translational Initiation Factor eIF4E in Protists.

PubMed

Jagus, Rosemary; Bachvaroff, Tsvetan R; Joshi, Bhavesh; Place, Allen R

2012-01-01

The greatest diversity of eukaryotic species is within the microbial eukaryotes, the protists, with plants and fungi/metazoa representing just two of the estimated seventy five lineages of eukaryotes. Protists are a diverse group characterized by unusual genome features and a wide range of genome sizes from 8.2 Mb in the apicomplexan parasite Babesia bovis to 112,000-220,050 Mb in the dinoflagellate Prorocentrum micans. Protists possess numerous cellular, molecular and biochemical traits not observed in "text-book" model organisms. These features challenge some of the concepts and assumptions about the regulation of gene expression in eukaryotes. Like multicellular eukaryotes, many protists encode multiple eIF4Es, but few functional studies have been undertaken except in parasitic species. An earlier phylogenetic analysis of protist eIF4Es indicated that they cannot be grouped within the three classes that describe eIF4E family members from multicellular organisms. Many more protist sequences are now available from which three clades can be recognized that are distinct from the plant/fungi/metazoan classes. Understanding of the protist eIF4Es will be facilitated as more sequences become available particularly for the under-represented opisthokonts and amoebozoa. Similarly, a better understanding of eIF4Es within each clade will develop as more functional studies of protist eIF4Es are completed.

Diversity of Eukaryotic Translational Initiation Factor eIF4E in Protists

PubMed Central

Jagus, Rosemary; Bachvaroff, Tsvetan R.; Joshi, Bhavesh; Place, Allen R.

2012-01-01

The greatest diversity of eukaryotic species is within the microbial eukaryotes, the protists, with plants and fungi/metazoa representing just two of the estimated seventy five lineages of eukaryotes. Protists are a diverse group characterized by unusual genome features and a wide range of genome sizes from 8.2 Mb in the apicomplexan parasite Babesia bovis to 112,000-220,050 Mb in the dinoflagellate Prorocentrum micans. Protists possess numerous cellular, molecular and biochemical traits not observed in “text-book” model organisms. These features challenge some of the concepts and assumptions about the regulation of gene expression in eukaryotes. Like multicellular eukaryotes, many protists encode multiple eIF4Es, but few functional studies have been undertaken except in parasitic species. An earlier phylogenetic analysis of protist eIF4Es indicated that they cannot be grouped within the three classes that describe eIF4E family members from multicellular organisms. Many more protist sequences are now available from which three clades can be recognized that are distinct from the plant/fungi/metazoan classes. Understanding of the protist eIF4Es will be facilitated as more sequences become available particularly for the under-represented opisthokonts and amoebozoa. Similarly, a better understanding of eIF4Es within each clade will develop as more functional studies of protist eIF4Es are completed. PMID:22778692

RNA Initiation with Dinucleoside Monophosphates during Transcription of Bacteriophage T4 DNA with RNA Polymerase of Escherichia coli

PubMed Central

Hoffman, David J.; Niyogi, Salil K.

1973-01-01

The effects of dinucleoside monophosphates on the transcription of phage T4 DNA by E. coli RNA polymerase have been examined at various concentrations of the sigma subunit and extremely low concentration of ribonucleoside triphosphate. The following conclusions were reached: (i) Labeled specific dinucleoside monophosphates are incorporated as chain initiators. (ii) When the ratio of sigma factor to core enzyme is small, there is a general stimulation by most 5′-guanosyl dinucleoside monophosphates. (iii) When the ratio is increased or holoenzyme is present, ApU, CpA, UpA, and GpU are the most effective stimulators. (iv) At high concentrations of sigma factor, only certain adenosine-containing dinucleoside monophosphates (ApU, CpA, UpA, and ApA) stimulate the reaction. (v) Competition hybridization studies indicate that the RNAs stimulated by dinucleoside monophosphates (ApU, CpA, UpA, and GpU) are of the T4 “early” type. (vi) Studies involving both combinations of stimulatory dinucleoside monophosphates and competitive effects of these compounds on chain initiation by ATP and GTP suggest that the stimulatory dinucleoside monophosphates act as chain initiators and may recognize part of a continuous sequence in a promoter region. Studies based on the incorporation of 3H-labeled stimulatory dinucleoside monophosphates support the above conclusions. PMID:4568732

Concurrent use of methotrexate and celecoxib increases risk of silent liver fibrosis in rheumatoid arthritis patients with subclinical reduced kidney function.

PubMed

Park, Jin Su; Park, Min-Chan; Park, Yong-Beom; Lee, Soo-Kon; Lee, Sang-Won

2014-01-01

We evaluated the effects of concurrent use of methotrexate and celecoxib on silent liver and kidney damages in rheumatoid arthritis (RA) patients. We enrolled 92 RA patients with normal laboratory results related to liver and kidney functions, who had received methotrexate and celecoxib concurrently over 6 months. Liver stiffness measurement (LSM) using transient elastography and ultrasonography were performed along with blood and urine tests. Estimated glomerular filtration rate (eGFR) was calculated by both the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and the Modification of Diet in Renal Disease (MDRD) equations. Initial eGFR represented kidney function at the time of the initiation of celecoxib. The cutoff for abnormal LSM values was adopted as 5.3 kPa. The optimal cutoff of each eGFR for abnormal LSM values was also calculated. The median age of patients was 55 years old (74 women). The median LSM was 4.4 kPa and the median eGFRs and median initial eGFRs ranged from 89 to 99 mL/min/1.73 m(2). The cumulative doses of methotrexate and celecoxib and their concurrent administration duration did not affect LSM values and eGFRs. Both eGFRs were significantly associated with LSM values. Patients with initial eGFR(CKD-EPI), initial eGFR(MDRD), and eGFR(CKD-EPI) below each optimal cutoff had significantly high risks for silent liver fibrosis (RR 9.4, 10.3, and 4.4, p < 0.001, respectively). Both initial eGFRs (CKD-EPI and MDRD) and eGFR (CKD-EPI) were significant predictors for the development of silent liver fibrosis in RA patients who had received methotrexate and celecoxib concurrently for at least 6 months.

Ohio Army National Guard Mental Health Initiative: Risk and Resilience Factors for Combat-Related Posttraumatic Psychopathology and Post Combat Adjustment

DTIC Science & Technology

2012-10-01

data collection (beginning August 2012) thus far:  Telephone Survey N=1456 as of October 9, 2012:  Year 4 follow up interviews: N=1223  Dynamic...a0024663, Epub ahead of print ( August 8). Kessler, R.C., Berglund, P., Demler, O., Jin, R., Merikangas, K.R., Walters, E.E., 2005. Lifetime...administration closed on July 31, 2012. A summary of enrollment activity since the last CR is as follows (data reported as of August 31, 2012):  1,395

Translational signaling responses preceding resistance training-mediated myofiber hypertrophy in young and old humans

PubMed Central

Mayhew, David L.; Kim, Jeong-su; Cross, James M.; Ferrando, Arny A.

2009-01-01

While skeletal muscle protein accretion during resistance training (RT)-mediated myofiber hypertrophy is thought to result from upregulated translation initiation signaling, this concept is based on responses to a single bout of unaccustomed resistance exercise (RE) with no measure of hypertrophy across RT. Further, aging appears to affect acute responses to RE, but whether age differences in responsiveness persist during RT leading to impaired RT adaptation is unclear. We therefore tested whether muscle protein fractional synthesis rate (FSR) and Akt/mammalian target of rapamycin (mTOR) signaling in response to unaccustomed RE differed in old vs. young adults, and whether age differences in acute responsiveness were associated with differences in muscle hypertrophy after 16 wk of RT. Fifteen old and 21 young adult subjects completed the 16-wk study. The phosphorylation states of Akt, S6K1, ribosomal protein S6 (RPS6), eukaryotic initiation factor 4E (eIF4E) binding protein (4EBP1), eIF4E, and eIF4G were all elevated (23–199%) 24 h after a bout of unaccustomed RE. A concomitant 62% increase in FSR was found in a subset (6 old, 8 young). Age × time interaction was found only for RPS6 phosphorylation (+335% in old subjects only), while there was an interaction trend (P = 0.084) for FSR (+96% in young subjects only). After 16 wk of RT, gains in muscle mass, type II myofiber size, and voluntary strength were similar in young and old subjects. In conclusion, at the level of translational signaling, we found no evidence of impaired responsiveness among older adults, and for the first time, we show that changes in translational signaling after unaccustomed RE were associated with substantial muscle protein accretion (hypertrophy) during continued RT. PMID:19589955

Pharmacogenetic inhibition of eIF4E-dependent Mmp9 mRNA translation reverses fragile X syndrome-like phenotypes.

PubMed

Gkogkas, Christos G; Khoutorsky, Arkady; Cao, Ruifeng; Jafarnejad, Seyed Mehdi; Prager-Khoutorsky, Masha; Giannakas, Nikolaos; Kaminari, Archontia; Fragkouli, Apostolia; Nader, Karim; Price, Theodore J; Konicek, Bruce W; Graff, Jeremy R; Tzinia, Athina K; Lacaille, Jean-Claude; Sonenberg, Nahum

2014-12-11

Fragile X syndrome (FXS) is the leading genetic cause of autism. Mutations in Fmr1 (fragile X mental retardation 1 gene) engender exaggerated translation resulting in dendritic spine dysmorphogenesis, synaptic plasticity alterations, and behavioral deficits in mice, which are reminiscent of FXS phenotypes. Using postmortem brains from FXS patients and Fmr1 knockout mice (Fmr1(-/y)), we show that phosphorylation of the mRNA 5' cap binding protein, eukaryotic initiation factor 4E (eIF4E), is elevated concomitant with increased expression of matrix metalloproteinase 9 (MMP-9) protein. Genetic or pharmacological reduction of eIF4E phosphorylation rescued core behavioral deficits, synaptic plasticity alterations, and dendritic spine morphology defects via reducing exaggerated translation of Mmp9 mRNA in Fmr1(-/y) mice, whereas MMP-9 overexpression produced several FXS-like phenotypes. These results uncover a mechanism of regulation of synaptic function by translational control of Mmp-9 in FXS, which opens the possibility of new treatment avenues for the diverse neurological and psychiatric aspects of FXS. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

An efficient viral vector for functional genomic studies of Prunus fruit trees and its induced resistance to Plum pox virus via silencing of a host factor gene.

PubMed

Cui, Hongguang; Wang, Aiming

2017-03-01

RNA silencing is a powerful technology for molecular characterization of gene functions in plants. A commonly used approach to the induction of RNA silencing is through genetic transformation. A potent alternative is to use a modified viral vector for virus-induced gene silencing (VIGS) to degrade RNA molecules sharing similar nucleotide sequence. Unfortunately, genomic studies in many allogamous woody perennials such as peach are severely hindered because they have a long juvenile period and are recalcitrant to genetic transformation. Here, we report the development of a viral vector derived from Prunus necrotic ringspot virus (PNRSV), a widespread fruit tree virus that is endemic in all Prunus fruit production countries and regions in the world. We show that the modified PNRSV vector, harbouring the sense-orientated target gene sequence of 100-200 bp in length in genomic RNA3, could efficiently trigger the silencing of a transgene or an endogenous gene in the model plant Nicotiana benthamiana. We further demonstrate that the PNRSV-based vector could be manipulated to silence endogenous genes in peach such as eukaryotic translation initiation factor 4E isoform (eIF(iso)4E), a host factor of many potyviruses including Plum pox virus (PPV). Moreover, the eIF(iso)4E-knocked down peach plants were resistant to PPV. This work opens a potential avenue for the control of virus diseases in perennial trees via viral vector-mediated silencing of host factors, and the PNRSV vector may serve as a powerful molecular tool for functional genomic studies of Prunus fruit trees. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Multi-functional regulation of 4E-BP gene expression by the Ccr4-Not complex.

PubMed

Okada, Hirokazu; Schittenhelm, Ralf B; Straessle, Anna; Hafen, Ernst

2015-01-01

The mechanistic target of rapamycin (mTOR) signaling pathway is highly conserved from yeast to humans. It senses various environmental cues to regulate cellular growth and homeostasis. Deregulation of the pathway has been implicated in many pathological conditions including cancer. Phosphorylation cascades through the pathway have been extensively studied but not much is known about the regulation of gene expression of the pathway components. Here, we report that the mRNA level of eukaryotic translation initiation factor (eIF) subunit 4E-binding protein (4E-BP) gene, one of the key mTOR signaling components, is regulated by the highly conserved Ccr4-Not complex. RNAi knockdown of Not1, a putative scaffold protein of this protein complex, increases the mRNA level of 4E-BP in Drosophila Kc cells. Examination of the gene expression mechanism using reporter swap constructs reveals that Not1 depletion increases reporter mRNAs with the 3'UTR of 4E-BP gene, but decreases the ones with the 4E-BP promoter region, suggesting that Ccr4-Not complex regulates both degradation and transcription of 4E-BP mRNA. These results indicate that the Ccr4-Not complex controls expression of a single gene at multiple levels and adjusts the magnitude of the total effect. Thus, our study reveals a novel regulatory mechanism of a key component of the mTOR signaling pathway at the level of gene expression.

The adenovirus E4-ORF3 protein functions as a SUMO E3 ligase for TIF-1γ sumoylation and poly-SUMO chain elongation.

PubMed

Sohn, Sook-Young; Hearing, Patrick

2016-06-14

The adenovirus (Ad) early region 4 (E4)-ORF3 protein regulates diverse cellular processes to optimize the host environment for the establishment of Ad replication. E4-ORF3 self-assembles into multimers to form a nuclear scaffold in infected cells and creates distinct binding interfaces for different cellular target proteins. Previous studies have shown that the Ad5 E4-ORF3 protein induces sumoylation of multiple cellular proteins and subsequent proteasomal degradation of some of them, but the detailed mechanism of E4-ORF3 function remained unknown. Here, we investigate the role of E4-ORF3 in the sumoylation process by using transcription intermediary factor (TIF)-1γ as a substrate. Remarkably, we discovered that purified E4-ORF3 protein stimulates TIF-1γ sumoylation in vitro, demonstrating that E4-ORF3 acts as a small ubiquitin-like modifier (SUMO) E3 ligase. Furthermore, E4-ORF3 significantly increases poly-SUMO3 chain formation in vitro in the absence of substrate, showing that E4-ORF3 has SUMO E4 elongase activity. An E4-ORF3 mutant, which is defective in protein multimerization, exhibited severely decreased activity, demonstrating that E4-ORF3 self-assembly is required for these activities. Using a SUMO3 mutant, K11R, we found that E4-ORF3 facilitates the initial acceptor SUMO3 conjugation to TIF-1γ as well as poly-SUMO chain elongation. The E4-ORF3 protein displays no SUMO-targeted ubiquitin ligase activity in our assay system. These studies reveal the mechanism by which E4-ORF3 targets specific cellular proteins for sumoylation and proteasomal degradation and provide significant insight into how a small viral protein can play a role as a SUMO E3 ligase and E4-like SUMO elongase to impact a variety of cellular responses.

Leucine supplementation of a chronically restricted protein and energy diet enhances mTOR pathway activation but not muscle protein synthesis in neonatal pigs.

PubMed

Manjarín, Rodrigo; Columbus, Daniel A; Suryawan, Agus; Nguyen, Hanh V; Hernandez-García, Adriana D; Hoang, Nguyet-Minh; Fiorotto, Marta L; Davis, Teresa

2016-01-01

Suboptimal nutrient intake represents a limiting factor for growth and long-term survival of low-birth weight infants. The objective of this study was to determine if in neonates who can consume only 70 % of their protein and energy requirements for 8 days, enteral leucine supplementation will upregulate the mammalian target of rapamycin (mTOR) pathway in skeletal muscle, leading to an increase in protein synthesis and muscle anabolism. Nineteen 4-day-old piglets were fed by gastric tube 1 of 3 diets, containing (kg body weight(-1) · day(-1)) 16 g protein and 190 kcal (CON), 10.9 g protein and 132 kcal (R), or 10.8 g protein + 0.2 % leucine and 136 kcal (RL) at 4-h intervals for 8 days. On day 8, plasma AA and insulin levels were measured during 6 post-feeding intervals, and muscle protein synthesis rate and mTOR signaling proteins were determined at 120 min post-feeding. At 120 min, leucine was highest in RL (P < 0.001), whereas insulin, isoleucine and valine were lower in RL and R compared to CON (P < 0.001). Compared to RL and R, the CON diet increased (P < 0.01) body weight, protein synthesis, phosphorylation of S6 kinase (p-S6K1) and 4E-binding protein (p-4EBP1), and activation of eukaryotic initiation factor 4 complex (eIF4E · eIF4G). RL increased (P ≤ 0.01) p-S6K1, p-4EBP1 and eIF4E · eIF4G compared to R. In conclusion, when protein and energy intakes are restricted for 8 days, leucine supplementation increases muscle mTOR activation, but does not improve body weight gain or enhance skeletal muscle protein synthesis in neonatal pigs.

Defect in the GTPase activating protein (GAP) function of eIF5 causes repression of GCN4 translation.

PubMed

Antony A, Charles; Alone, Pankaj V

2017-05-13

In eukaryotes, the eIF5 protein plays an important role in translation start site selection by providing the GAP (GTPase activating protein) function. However, in yeast translation initiation fidelity defective eIF5 G31R mutant causes preferential utilization of UUG as initiation codon and is termed as Suppressor of initiation codon (Sui - ) phenotype due to its hyper GTPase activity. The eIF5 G31R mutant dominantly represses GCN4 expression and confers sensitivity to 3-Amino-1,2,4-Trizole (3AT) induced starvation. The down-regulation of the GCN4 expression (Gcn - phenotype) in the eIF5 G31R mutant was not because of leaky scanning defects; rather was due to the utilization of upUUG initiation codons at the 5' regulatory region present between uORF1 and the main GCN4 ORF. Copyright © 2017 Elsevier Inc. All rights reserved.

Trends in baseline CD4 cell counts and risk factors for late antiretroviral therapy initiation among HIV-positive patients in Shanghai, a retrospective cross-sectional study.

PubMed

Sun, Jianjun; Liu, Li; Shen, Jiayin; Chen, Panpan; Lu, Hongzhou

2017-04-19

There are few studies focus on the factors underlying the late initiation of ART in China. We analyzed the trends in the median CD4 cell counts among different patient groups over time and the risk factors for the late initiation of ART in Shanghai, China. A retrospective cross-sectional survey was made in the Department of Infectious Disease of Shanghai Public Health Clinical Center which is a designated diagnosis and treatment center for HIV-positive patients in Shanghai during the period of January 1st, 2008--June 30th, 2014. Late ART initiation was defined as a CD4 cell count <200 cells/mm 3 or having a clinical AIDS diagnosis prior to ART initiation. Trends in the median CD4 cell count at ART initiation and the proportion of late ART initiation by year were evaluated using Spearman's correlations and Chi-squared methods, respectively. We used a logistic regression model to analyze the risk factors for late ART initiation. The related factors collected in the multivariate model were the patient's age, gender, infection routes and marital status. A total of 3796 patients were analyzed in this study, with a median baseline CD4 cell count of 205 cells/mm 3 [interquartile range: 75-287]. The median CD4 cell counts of patients initiating ART late increased from 76 cells/mm 3 in 2008 to 103 cells/mm 3 in 2014 (p < 0.001), and the proportion of late ART initiation decreased from 80% to 45% (p < 0.001). The risk factors for late ART initiation were male gender, heterosexual transmission and older age (>30 years) (p < 0.001). Notable improvements were made in the median CD4 cell count at ART initiation and the proportion of late ART initiation from 2008 to 2014. However, persons with high risk of HIV exposure who are male, older even heterosexual orientation should be given more opportunities to receive frequently screening, earlier diagnoses and timely treatment.

Deregulation of EIF4E: a novel mechanism for autism.

PubMed

Neves-Pereira, M; Müller, B; Massie, D; Williams, J H G; O'Brien, P C M; Hughes, A; Shen, S-B; Clair, David St; Miedzybrodzka, Z

2009-11-01

Autism is a common childhood onset neurodevelopmental disorder, characterised by severe and sustained impairment of social interaction and social communication, as well as a notably restricted repertoire of activities and interests. Its aetiology is multifactorial with a strong genetic basis. EIF4E is the rate limiting component of eukaryotic translation initiation, and plays a key role in learning and memory through its control of translation within the synapse. EIF4E mediated translation is the final common process modulated by the mammalian target of rapamycin (mTOR), PTEN and fragile X mental retardation protein (FMRP) pathways, which are implicated in autism. Linkage of autism to the EIF4E region on chromosome 4q has been found in genome wide linkage studies. The authors present evidence that directly implicates EIF4E in autism. In a boy with classic autism, the authors observed a de novo chromosome translocation between 4q and 5q and mapped the breakpoint site to within a proposed alternative transcript of EIF4E. They then screened 120 autism families for mutations and found two unrelated families where in each case both autistic siblings and one of the parents harboured the same single nucleotide insertion at position -25 in the basal element of the EIF4E promoter. Electrophoretic mobility shift assays and reporter gene studies show that this mutation enhances binding of a nuclear factor and EIF4E promoter activity. These observations implicate EIF4E, and more specifically control of EIF4E activity, directly in autism. The findings raise the exciting possibility that pharmacological manipulation of EIF4E may provide therapeutic benefit for those with autism caused by disturbance of the converging pathways controlling EIF4E activity.

Long-term treatment of bile duct-ligated rats with rapamycin (sirolimus) significantly attenuates liver fibrosis: analysis of the underlying mechanisms.

PubMed

Biecker, Erwin; De Gottardi, Andrea; Neef, Markus; Unternährer, Matthias; Schneider, Vreni; Ledermann, Monika; Sägesser, Hans; Shaw, Sidney; Reichen, Jürg

2005-06-01

Rapamycin is an immunosuppressant with antiproliferative properties. We investigated whether rapamycin treatment of bile duct-ligated (BDL) rats is capable of inhibiting liver fibrosis and thereby affecting hemodynamics. Following BDL, rats were treated for 28 days with rapamycin (BDL SIR). BDL animals without drug treatment (BDL CTR) and sham-operated animals served as controls. After 28 days, hemodynamics were measured, and livers were harvested for histology/immunohistochemistry. Liver mRNA levels of transforming growth factor (TGF)-beta1, connective tissue growth factor (CTGF), platelet-derived growth factor (PDGF)-beta, cyclin-dependent kinase inhibitor p27(kip) (p27), and cyclin-dependent kinase inhibitor p21(WAF1/CIP1) (p21) were quantified by real-time polymerase chain reaction. Liver protein levels of p27, p21, p70 S6 kinase (p70(s6k)), phosphorylated p70(s6k) (p-p70(s6k)), eukaryotic initiation factor 4E-binding protein (4E-BP1), p-4E-BP1 (Thr37/46), and p-4E-BP1 (Ser65/Thr70) were determined by Western blotting. Portal vein pressure was lower in BDL SIR than in BDL CTR animals. Volume fractions of connective tissue, bile duct epithelial, and desmin- and actin-positive cells were lower in BDL SIR than in BDL CTR rats. On the mRNA level, TGF-beta1, CTGF, and PDGF were decreased by rapamycin. p27 and p21 mRNA did not differ. On the protein level, rapamycin increased p27 and decreased p21 levels. Levels of nonphosphorylated p70(s6k) and 4E-BP1 did not vary between groups, but levels of p-p70(s6k) were decreased by rapamycin. Rapamycin had no effect on p-4E-BP1 (Thr37/46) and p-4E-BP1 (Ser65/Thr70) levels. In BDL rats, rapamycin inhibits liver fibrosis and ameliorates portal hypertension. This is paralleled by decreased levels of TGF-beta1, CTGF, and PDGF. Rapamycin influences the cell cycle by up-regulation of p27, down-regulation of p21, and inhibition of p70(s6k) phosphorylation.

Antibiotic drug rifabutin is effective against lung cancer cells by targeting the eIF4E-β-catenin axis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Ji; Huang, Yijiang; Gao, Yunsuo

The essential roles of overexpression of eukaryotic translation initiation factor 4E (eIF4E) and aberrant activation of β-catenin in lung cancer development have been recently identified. However, whether there is a direct connection between eIF4E overexpression and β-catenin activation in lung cancer cells is unknown. In this study, we show that antibiotic drug rifabutin targets human lung cancer cells via inhibition of eIF4E-β-catenin axis. Rifabutin is effectively against lung cancer cells in in vitro cultured cells and in vivo xenograft mouse model through inhibiting proliferation and inducing apoptosis. Mechanistically, eIF4E regulates β-catenin activity in lung cancer cells as shown by the increased β-cateninmore » phosphorylation and activity in cells overexpressing eIF4E, and furthermore that the regulation is dependent on phosphorylation at S209. Rifabutin suppresses eIF4E phosphorylation, leads to decreased β-catenin phosphorylation and its subsequent transcriptional activities. Depletion of eIF4E abolishes the inhibitory effects of rifabutin on β-catenin activities and overexpression of β-catenin reverses the inhibitory effects of rifabutin on cell growth and survival, further confirming that rifabutin acts on lung cancer cells via targeting eIF4E- β-catenin axis. Our findings identify the eIF4E- β-catenin axis as a critical regulator of lung cancer cell growth and survival, and suggest that its pharmacological inhibition may be therapeutically useful in lung cancer. - Highlights: • Rifabutin targets EGFR-mutated lung cancer cells in vitro and in vivo. • eIF4E phosphorylation regulates β-catenin activity in lung cancer cells. • Rifabutin acts on lung cancer cells via eIF4E- β-catenin axis. • Rifabutin can be repurposed for lung cancer treatment.« less

Identification of EhTIF-IA: The putative E. histolytica orthologue of the human ribosomal RNA transcription initiation factor-IA.

PubMed

Srivastava, Ankita; Bhattacharya, Alok; Bhattacharya, Sudha; Jhingan, Gagan Deep

2016-03-01

Initiation of rDNA transcription requires the assembly of a specific multi-protein complex at the rDNA promoter containing the RNA Pol I with auxiliary factors. One of these factors is known as Rrn3P in yeast and Transcription Initiation Factor IA (TIF-IA) in mammals. Rrn3p/TIF-IA serves as a bridge between RNA Pol I and the pre-initiation complex at the promoter. It is phosphorylated at multiple sites and is involved in regulation of rDNA transcription in a growth-dependent manner. In the early branching parasitic protist Entamoeba histolytica, the rRNA genes are present exclusively on circular extra chromosomal plasmids. The protein factors involved in regulation of rDNA transcription in E. histolytica are not known. We have identified the E. histolytica equivalent of TIF-1A (EhTIF-IA) by homology search within the database and was further cloned and expressed. Immuno-localization studies showed that EhTIF-IA co-localized partially with fibrillarin in the peripherally localized nucleolus. EhTIF-IA was shown to interact with the RNA Pol I-specific subunit RPA12 both in vivo and in vitro. Mass spectroscopy data identified RNA Pol I-specific subunits and other nucleolar proteins to be the interacting partners of EhTIF-IA. Our study demonstrates for the first time a conserved putative RNA Pol I transcription factor TIF-IA in E. histolytica.

Main factors in E-Learning for the Equivalency Education Program (E-LEEP)

NASA Astrophysics Data System (ADS)

Yel, M. B.; Sfenrianto

2018-03-01

There is a tremendous learning gap between formal education and non-formal education. E-Learning can facilitate non-formal education learners in improving the learning process. In this study, we present the main factors behind the E-learning for the Equivalency Education Program (E-LEEP) initiative in Indonesia. There are four main factors proposed, namely: standardization, learning materials, learning process, and learners’ characteristics. Each factor supports each other to achieve the learning process of E-LEEP in Indonesia. Although not yet proven, the E-learning should be developed followed the main factors for the non-formal education. This is because those factors can improve the quality of E-Learning for the Equivalency Education Program.

Moco biosynthesis and the ATAC acetyltransferase engage translation initiation by inhibiting latent PKR activity.

PubMed

Suganuma, Tamaki; Swanson, Selene K; Florens, Laurence; Washburn, Michael P; Workman, Jerry L

2016-02-01

Molybdenum cofactor (Moco) biosynthesis is linked to c-Jun N-terminal kinase (JNK) signaling in Drosophila through MoaE, a molybdopterin (MPT) synthase subunit that is also a component of the Ada Two A containing (ATAC) acetyltransferase complex. Here, we show that human MPT synthase and ATAC inhibited PKR, a double-stranded RNA-dependent protein kinase, to facilitate translation initiation of iron-responsive mRNA. MPT synthase and ATAC directly interacted with PKR and suppressed latent autophosphorylation of PKR and its downstream phosphorylation of JNK and eukaryotic initiation factor 2α (eIF2α). The suppression of eIF2α phosphorylation via MPT synthase and ATAC prevented sequestration of the guanine nucleotide exchange factor eIF2B, which recycles eIF2-GDP to eIF2-GTP, resulting in the promotion of translation initiation. Indeed, translation of the iron storage protein, ferritin, was reduced in the absence of MPT synthase or ATAC subunits. Thus, MPT synthase and ATAC regulate latent PKR signaling and link transcription and translation initiation. © The Author (2015). Published by Oxford University Press on behalf of Journal of Molecular Cell Biology, IBCB, SIBS, CAS. All rights reserved.

Timing of dialysis initiation in transplant-naive and failed transplant patients

PubMed Central

Molnar, Miklos Z.; Ojo, Akinlolu O.; Bunnapradist, Suphamai; Kovesdy, Csaba P.; Kalantar-Zadeh, Kamyar

2017-01-01

Over the past two decades, most guidelines have advocated early dialysis initiation on the basis of studies showing improved survival in patients starting dialysis early. These recommendations led to an increase in the proportion of patients initiating dialysis with an estimated glomerular filtration rate (eGFR) >10 ml/min/1.73 m2, from 20% in 1996 to 52% in 2008. During this period, patients starting dialysis with an eGFR ≥15 ml/min/1.73 m2 increased from 4% to 17%. However, recent studies have failed to substantiate a benefit of early dialysis initiation and some data have suggested worse outcomes in patients starting dialysis with a higher eGFR. Several reasons for this seemingly paradoxical observation have been suggested, including the fact that patients requiring early dialysis are likely to have more severe symptoms and comorbidities, leading to confounding by indication, as well as biological mechanisms that causally relate early dialysis therapy to adverse outcomes. Dialysis reinitiation in patients with a failing renal allograft encounters similar problems. However, unique factors associated with a failed allograft means that the optimal timing of dialysis initiation in failed transplant patients might differ from that in transplant-naive patients. In this Review, we will discuss studies of dialysis initiation and compare risks and benefits of early versus late dialysis therapy. PMID:22371250

Engineering of CRISPR/Cas9‐mediated potyvirus resistance in transgene‐free Arabidopsis plants

PubMed Central

Pyott, Douglas E.; Sheehan, Emma

2016-01-01

Summary Members of the eukaryotic translation initiation factor (eIF) gene family, including eIF4E and its paralogue eIF(iso)4E, have previously been identified as recessive resistance alleles against various potyviruses in a range of different hosts. However, the identification and introgression of these alleles into important crop species is often limited. In this study, we utilise CRISPR/Cas9 technology to introduce sequence‐specific deleterious point mutations at the eIF(iso)4E locus in Arabidopsis thaliana to successfully engineer complete resistance to Turnip mosaic virus (TuMV), a major pathogen in field‐grown vegetable crops. By segregating the induced mutation from the CRISPR/Cas9 transgene, we outline a framework for the production of heritable, homozygous mutations in the transgene‐free T2 generation in self‐pollinating species. Analysis of dry weights and flowering times for four independent T3 lines revealed no differences from wild‐type plants under standard growth conditions, suggesting that homozygous mutations in eIF(iso)4E do not affect plant vigour. Thus, the established CRISPR/Cas9 technology provides a new approach for the generation of Potyvirus resistance alleles in important crops without the use of persistent transgenes. PMID:27103354

Is Follow-Up Testing with the FilmArray Gastrointestinal Multiplex PCR Panel Necessary?

PubMed Central

Park, Sholhui; Hitchcock, Matthew M.; Gomez, Carlos A.

2017-01-01

ABSTRACT The FilmArray gastrointestinal (GI) panel (BioFire Diagnostics, Salt Lake City, UT) is a simple, sample-to-answer, on-demand, multiplex, nucleic acid amplification test for syndromic diagnosis of infectious gastroenteritis. The aim of this study was to measure the yield of follow-up testing with FilmArray GI panel within 4 weeks of an initial test. Consecutive adult and pediatric patients tested at an academic institution between August 2015 and June 2016 were included in this study. Of 145 follow-up tests in 106 unique patients with an initial negative result, 134 (92.4%) tests and 98 (92.5%) patients remained negative upon follow-up testing. Excluding targets that are not reported at this institution (Clostridium difficile, enteroaggregative Escherichia coli, enteropathogenic E. coli, and enterotoxigenic E. coli), 137 (94.5%) follow-up tests and 101 (95.3%) patients remained negative. Weekly conversion rates were not significantly different across the 4-week follow-up interval. No epidemiological or clinical factors were significantly associated with a negative to positive conversion. Of 80 follow-up tests in patients with an initial positive result, 43 (53.8%) remained positive for the same target, 34 (42.5%) were negative, and 3 were positive for a different target (3.8%). Follow-up testing with FilmArray GI panel within 4 weeks of a negative result rarely changed the initial result, and the follow-up test reverted to negative less than half the time after an initial positive result. In the absence of clinical or epidemiological evidence for a new infection, follow-up testing should be limited and FilmArray GI panel should not be used as a test of cure. PMID:28122874

RACK1-mediated translation control promotes liver fibrogenesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Min; Peng, Peike; Wang, Jiajun

Activation of quiescent hepatic stellate cells (HSCs) is the central event of liver fibrosis. The translational machinery is an optimized molecular network that affects cellular homoeostasis and diseases, whereas the role of protein translation in HSCs activation and liver fibrosis is little defined. Our previous report suggests that up-regulation of receptor for activated C-kinase 1(RACK1) in HSCs is critical for liver fibrogenesis. In this study, we found that RACK1 promoted macrophage conditioned medium (MCM)-induced assembly of eIF4F and phosphorylation of eIF4E in primary HSCs. RACK1 enhanced the translation and expression of pro-fibrogenic factors collagen 1α1, snail and cyclin E1 inducedmore » by MCM. Administration of PP242 or knock-down of eIF4E suppressed RACK1-stimulated collagen 1α1 production, proliferation and migration in primary HSCs. In addition, depletion of eIF4E attenuated thioacetamide (TAA)-induced liver fibrosis in vivo. Our data suggest that RACK1-mediated stimulation of cap-dependent translation plays crucial roles in HSCs activation and liver fibrogenesis, and targeting translation initiation could be a promising strategy for the treatment of liver fibrosis. - Highlights: • RACK1 induces the assembly of eIF4F and phosphorylation of eIF4E in primary HSCs. • RACK1 stimulates the translation of collagen 1α1, snail and cyclin E1 in HSCs. • RACK1 promotes HSCs activation via cap-mediated translation. • Depletion of eIF4E suppresses liver fibrogenesis in vivo.« less

Fusel Alcohols Regulate Translation Initiation by Inhibiting eIF2B to Reduce Ternary Complex in a Mechanism That May Involve Altering the Integrity and Dynamics of the eIF2B Body

PubMed Central

Taylor, Eleanor J.; Campbell, Susan G.; Griffiths, Christian D.; Reid, Peter J.; Slaven, John W.; Harrison, Richard J.; Sims, Paul F.G.; Pavitt, Graham D.; Delneri, Daniela

2010-01-01

Recycling of eIF2-GDP to the GTP-bound form constitutes a core essential, regulated step in eukaryotic translation. This reaction is mediated by eIF2B, a heteropentameric factor with important links to human disease. eIF2 in the GTP-bound form binds to methionyl initiator tRNA to form a ternary complex, and the levels of this ternary complex can be a critical determinant of the rate of protein synthesis. Here we show that eIF2B serves as the target for translation inhibition by various fusel alcohols in yeast. Fusel alcohols are endpoint metabolites from amino acid catabolism, which signal nitrogen scarcity. We show that the inhibition of eIF2B leads to reduced ternary complex levels and that different eIF2B subunit mutants alter fusel alcohol sensitivity. A DNA tiling array strategy was developed that overcame difficulties in the identification of these mutants where the phenotypic distinctions were too subtle for classical complementation cloning. Fusel alcohols also lead to eIF2α dephosphorylation in a Sit4p-dependent manner. In yeast, eIF2B occupies a large cytoplasmic body where guanine nucleotide exchange on eIF2 can occur and be regulated. Fusel alcohols impact on both the movement and dynamics of this 2B body. Overall, these results confirm that the guanine nucleotide exchange factor, eIF2B, is targeted by fusel alcohols. Moreover, they highlight a potential connection between the movement or integrity of the 2B body and eIF2B regulation. PMID:20444979

Modulation of tumor eIF4E by antisense inhibition: A phase I/II translational clinical trial of ISIS 183750-an antisense oligonucleotide against eIF4E-in combination with irinotecan in solid tumors and irinotecan-refractory colorectal cancer.

PubMed

Duffy, A G; Makarova-Rusher, O V; Ulahannan, S V; Rahma, O E; Fioravanti, S; Walker, M; Abdullah, S; Raffeld, M; Anderson, V; Abi-Jaoudeh, N; Levy, E; Wood, B J; Lee, S; Tomita, Y; Trepel, J B; Steinberg, S M; Revenko, A S; MacLeod, A R; Peer, C J; Figg, W D; Greten, T F

2016-10-01

The eukaryotic translation initiation factor 4E (eIF4E) is a potent oncogene that is found to be dysregulated in 30% of human cancer, including colorectal carcinogenesis (CRC). ISIS 183750 is a second-generation antisense oligonucleotide (ASO) designed to inhibit the production of the eIF4E protein. In preclinical studies we found that EIF4e ASOs reduced expression of EIF4e mRNA and inhibited proliferation of colorectal carcinoma cells. An additive antiproliferative effect was observed in combination with irinotecan. We then performed a clinical trial evaluating this combination in patients with refractory cancer. No dose-limiting toxicities were seen but based on pharmacokinetic data and tolerability the dose of irinotecan was reduced to 160 mg/m(2) biweekly. Efficacy was evaluated in 15 patients with irinotecan-refractory colorectal cancer. The median time of disease control was 22.1 weeks. After ISIS 183750 treatment, peripheral blood levels of eIF4E mRNA were decreased in 13 of 19 patients. Matched pre- and posttreatment tumor biopsies showed decreased eIF4E mRNA levels in five of nine patients. In tumor tissue, the intracellular and stromal presence of ISIS 183750 was detected by IHC in all biopsied patients. Although there were no objective responses stable disease was seen in seven of 15 (47%) patients who were progressing before study entry, six of whom were stable at the time of the week 16 CT scan. We were also able to confirm through mandatory pre- and posttherapy tumor biopsies penetration of the ASO into the site of metastasis. © 2016 UICC.

Inactivation of Escherichia coli by citral.

PubMed

Somolinos, M; García, D; Condón, S; Mackey, B; Pagán, R

2010-06-01

The aim was to evaluate (i) the resistance of Escherichia coli BJ4 to citral in a buffer system as a function of citral concentration, treatment medium pH, storage time and initial inoculum size, (ii) the role of the sigma factor RpoS on citral resistance of E. coli, (iii) the role of the cell envelope damage in the mechanism of microbial inactivation by citral and (iiii) possible synergistic effects of mild heat treatment and pulsed electric fields (PEF) treatment combined with citral. The initial inoculum size greatly affected the efficacy of citral against E. coli cells. Exposure to 200 microl l(-1) of citral at pH 4.0 for 24 h at 20 degrees C caused the inactivation of more than 5 log(10) cycles of cells starting at an inoculum size of 10(6) or 10(7) CFU ml(-1), whereas increasing the cell concentration to 10(9) CFU ml(-1) caused <1 log(10) cycle of inactivation. Escherichia coli showed higher resistance to citral at pH 4.0 than pH 7.0. The rpoS null mutant strain E. coli BJ4L1 was less resistant to citral than the wild-type strain. Occurrence of sublethal injury to both the cytoplasmic and outer membranes was demonstrated by adding sodium chloride or bile salts to the recovery media. The majority of sublethally injured cells by citral required energy and lipid synthesis for repair. A strongly synergistic lethal effect was shown by mild heat treatment combined with citral but the presence of citral during the application of a PEF treatment did not show any advantage. This work confirms that cell envelope damage is an important event in citral inactivation of bacteria, and it describes the key factors on the inactivation of E. coli cells by citral. Knowledge about the mechanism of microbial inactivation by citral helps establish successful combined preservation treatments.

Efficient Cleavage of Ribosome-Associated Poly(A)-Binding Protein by Enterovirus 3C Protease

PubMed Central

Kuyumcu-Martinez, N. Muge; Joachims, Michelle; Lloyd, Richard E.

2002-01-01

Poliovirus (PV) causes a rapid and drastic inhibition of host cell cap-dependent protein synthesis during infection while preferentially allowing cap-independent translation of its own genomic RNA via an internal ribosome entry site element. Inhibition of cap-dependent translation is partly mediated by cleavage of an essential translation initiation factor, eIF4GI, during PV infection. In addition to cleavage of eIF4GI, cleavage of eIF4GII and poly(A)-binding protein (PABP) has been recently proposed to contribute to complete host translation shutoff; however, the relative importance of eIF4GII and PABP cleavage has not been determined. At times when cap-dependent translation is first blocked during infection, only 25 to 35% of the total cellular PABP is cleaved; therefore, we hypothesized that the pool of PABP associated with polysomes may be preferentially targeted by viral proteases. We have investigated what cleavage products of PABP are produced in vivo and the substrate determinants for cleavage of PABP by 2A protease (2Apro) or 3C protease (3Cpro). Our results show that PABP in ribosome-enriched fractions is preferentially cleaved in vitro and in vivo compared to PABP in other fractions. Furthermore, we have identified four N-terminal PABP cleavage products produced during PV infection and have shown that viral 3C protease generates three of the four cleavage products. Also, 3Cpro is more efficient in cleaving PABP in ribosome-enriched fractions than 2Apro in vitro. In addition, binding of PABP to poly(A) RNA stimulates 3Cpro-mediated cleavage and inhibits 2Apro-mediated cleavage. These results suggest that 3Cpro plays a major role in processing PABP during virus infection and that the interaction of PABP with translation initiation factors, ribosomes, or poly(A) RNA may promote its cleavage by viral 2A and 3C proteases. PMID:11836384

Predictors of Optimal Cognitive Aging in 80+ Women: The Women's Health Initiative Memory Study.

PubMed

Goveas, Joseph S; Rapp, Stephen R; Hogan, Patricia E; Driscoll, Ira; Tindle, Hilary A; Smith, J Carson; Kesler, Shelli R; Zaslavsky, Oleg; Rossom, Rebecca C; Ockene, Judith K; Yaffe, Kristine; Manson, JoAnn E; Resnick, Susan M; Espeland, Mark A

2016-03-01

Independent predictors of preserved cognitive functioning and factors associated with maintaining high preserved cognitive function in women ≥ 80 years remain elusive. Two thousand two hundred twenty-eight women with a mean age of 85 years who participated in the Women's Health Initiative Memory Study were classified as cognitively normal (n = 1,905, 85.5%), mild cognitive impairment (n = 88, 3.9%), dementia (n = 121, 5.4%) or other cognitive impairment (n = 114, n = 5.1%) by central adjudication. Global cognitive functioning was assessed using telephone interview for cognitive status-modified in those women who did not meet cognitive impairment criteria. Differences between women grouped by cognitive status with respect to each potential risk factor were assessed using chi-squared tests and t-tests. Backward stepwise logistic regression was used to select factors that were independently associated with cognitive status. Factors associated with preserved cognitive functioning were younger age, higher education, and family incomes, being non-Hispanic white, better emotional wellbeing, fewer depressive symptoms, more insomnia complaints, being free of diabetes, and not carrying the apolipoprotein E-epsilon 4 allele. Cognitively normal women who demonstrated sustained high preserved cognition were younger, more educated, and endorsed better self-reported general health, emotional wellbeing, and higher physical functioning. Addressing sociodemographic disparities such as income inequality, and targeting interventions to improve depressive symptoms and vascular risk factors, including diabetes, may play an important role in preserving cognition among women who survive to 80 years of age. Person-centered approaches that combine interventions to improve physical, cognitive, and psychosocial functioning may promote maintenance of high preserved cognitive health in the oldest-old. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Genomic responses in rat cerebral cortex after traumatic brain injury

PubMed Central

von Gertten, Christina; Morales, Amilcar Flores; Holmin, Staffan; Mathiesen, Tiit; Nordqvist, Ann-Christin Sandberg

2005-01-01

Background Traumatic brain injury (TBI) initiates a complex sequence of destructive and neuroprotective cellular responses. The initial mechanical injury is followed by an extended time period of secondary brain damage. Due to the complicated pathological picture a better understanding of the molecular events occurring during this secondary phase of injury is needed. This study was aimed at analysing gene expression patterns following cerebral cortical contusion in rat using high throughput microarray technology with the goal of identifying genes involved in an early and in a more delayed phase of trauma, as genomic responses behind secondary mechanisms likely are time-dependent. Results Among the upregulated genes 1 day post injury, were transcription factors and genes involved in metabolism, e.g. STAT-3, C/EBP-δ and cytochrome p450. At 4 days post injury we observed increased gene expression of inflammatory factors, proteases and their inhibitors, like cathepsins, α-2-macroglobulin and C1q. Notably, genes with biological function clustered to immune response were significantly upregulated 4 days after injury, which was not found following 1 day. Osteopontin and one of its receptors, CD-44, were both upregulated showing a local mRNA- and immunoreactivity pattern in and around the injury site. Fewer genes had decreased expression both 1 and 4 days post injury and included genes implicated in transport, metabolism, signalling, and extra cellular matrix formation, e.g. vitronectin, neuroserpin and angiotensinogen. Conclusion The different patterns of gene expression, with little overlap in genes, 1 and 4 days post injury showed time dependence in genomic responses to trauma. An early induction of factors involved in transcription could lead to the later inflammatory response with strongly upregulated CD-44 and osteopontin expression. An increased knowledge of genes regulating the pathological mechanisms in trauma will help to find future treatment targets. Since trauma is a risk factor for development of neurodegenerative disease, this knowledge may also reduce late negative effects. PMID:16318630

IMPACT Is a Developmentally Regulated Protein in Neurons That Opposes the Eukaryotic Initiation Factor 2α Kinase GCN2 in the modulation of Neurite Outgrowth*

PubMed Central

Roffé, Martín; Hajj, Glaucia N. M.; Azevedo, Hátylas F.; Alves, Viviane S.; Castilho, Beatriz A.

2013-01-01

The product of the mouse Imprinted and Ancient gene, IMPACT, is preferentially expressed in neurons. We have previously shown that IMPACT overexpression inhibits the activation of the protein kinase GCN2, which signals amino acid starvation. GCN2 phosphorylates the α-subunit of eukaryotic translation initiation factor 2 (eIF2α), resulting in inhibition of general protein synthesis but increased translation of specific messages, such as ATF4. GCN2 is also involved in the regulation of neuronal functions, controlling synaptic plasticity, memory, and feeding behavior. We show here that IMPACT abundance increases during differentiation of neurons and neuron-like N2a cells, whereas GCN2 displays lowered activation levels. Upon differentiation, IMPACT associates with translating ribosomes, enhances translation initiation, and down-regulates the expression of ATF4. We further show that endogenous IMPACT promotes neurite outgrowth whereas GCN2 is a strong inhibitor of spontaneous neuritogenesis. Together, these results uncover the participation of the GCN2-IMPACT module of translational regulation in a highly controlled step in the development of the nervous system. PMID:23447528

IMPACT is a developmentally regulated protein in neurons that opposes the eukaryotic initiation factor 2α kinase GCN2 in the modulation of neurite outgrowth.

PubMed

Roffé, Martín; Hajj, Glaucia N M; Azevedo, Hátylas F; Alves, Viviane S; Castilho, Beatriz A

2013-04-12

The product of the mouse Imprinted and Ancient gene, IMPACT, is preferentially expressed in neurons. We have previously shown that IMPACT overexpression inhibits the activation of the protein kinase GCN2, which signals amino acid starvation. GCN2 phosphorylates the α-subunit of eukaryotic translation initiation factor 2 (eIF2α), resulting in inhibition of general protein synthesis but increased translation of specific messages, such as ATF4. GCN2 is also involved in the regulation of neuronal functions, controlling synaptic plasticity, memory, and feeding behavior. We show here that IMPACT abundance increases during differentiation of neurons and neuron-like N2a cells, whereas GCN2 displays lowered activation levels. Upon differentiation, IMPACT associates with translating ribosomes, enhances translation initiation, and down-regulates the expression of ATF4. We further show that endogenous IMPACT promotes neurite outgrowth whereas GCN2 is a strong inhibitor of spontaneous neuritogenesis. Together, these results uncover the participation of the GCN2-IMPACT module of translational regulation in a highly controlled step in the development of the nervous system.

GENETIC INFLUENCE OF APOE4 GENOTYPE ON HIPPOCAMPAL MORPHOMETRY - AN N=725 SURFACE-BASED ADNI STUDY

PubMed Central

Shi, Jie; Leporé, Natasha; Gutman, Boris A.; Thompson, Paul M.; Baxter, Leslie C.; Caselli, Richard L.; Wang, Yalin

2014-01-01

The apolipoprotein E (APOE) e4 allele is the most prevalent genetic risk factor for Alzheimer’s disease (AD). Hippocampal volumes are generally smaller in AD patients carrying the e4 allele compared to e4 non-carriers. Here we examined the effect of APOE e4 on hippocampal morphometry in a large imaging database – the Alzheimer’s Disease Neuroimaging Initiative (ADNI). We automatically segmented and constructed hippocampal surfaces from the baseline MR images of 725 subjects with known APOE genotype information including 167 with AD, 354 with mild cognitive impairment (MCI), and 204 normal controls. High-order correspondences between hippocampal surfaces were enforced across subjects with a novel inverse consistent surface fluid registration method. Multivariate statistics consisting of multivariate tensor-based morphometry (mTBM) and radial distance were computed for surface deformation analysis. Using Hotelling’s T2 test, we found significant morphological deformation in APOE e4 carriers relative to non-carriers in the entire cohort as well as in the non-demented (pooled MCI and control) subjects, affecting the left hippocampus more than the right, and this effect was more pronounced in e4 homozygotes than heterozygotes. Our findings are consistent with previous studies that showed e4 carriers exhibit accelerated hippocampal atrophy; we extend these findings to a novel measure of hippocampal morphometry. Hippocampal morphometry has significant potential as an imaging biomarker of early stage AD. PMID:24453132

Normalizing translation through 4E-BP prevents mTOR-driven cortical mislamination and ameliorates aberrant neuron integration.

PubMed

Lin, Tiffany V; Hsieh, Lawrence; Kimura, Tomoki; Malone, Taylor J; Bordey, Angélique

2016-10-04

Hyperactive mammalian target of rapamycin complex 1 (mTORC1) is a shared molecular hallmark in several neurodevelopmental disorders characterized by abnormal brain cytoarchitecture. The mechanisms downstream of mTORC1 that are responsible for these defects remain unclear. We show that focally increasing mTORC1 activity during late corticogenesis leads to ectopic placement of upper-layer cortical neurons that does not require altered signaling in radial glia and is accompanied by changes in layer-specific molecular identity. Importantly, we found that decreasing cap-dependent translation by expressing a constitutively active mutant of the translational repressor eukaryotic initiation factor 4E-binding protein 1 (4E-BP1) prevents neuronal misplacement and soma enlargement, while partially rescuing dendritic hypertrophy induced by hyperactive mTORC1. Furthermore, overactivation of translation alone through knockdown of 4E-BP2 was sufficient to induce neuronal misplacement. These data show that many aspects of abnormal brain cytoarchitecture can be prevented by manipulating a single intracellular process downstream of mTORC1, cap-dependent translation.

Gating by tryptophan 73 exposes a cryptic pocket at the protein-binding interface of the oncogenic eIF4E protein.

PubMed

Lama, Dilraj; Brown, Christopher J; Lane, David P; Verma, Chandra S

2015-10-27

Targeting protein-protein interacting sites for potential therapeutic applications is a challenge in the development of inhibitors, and this becomes more difficult when these interfaces are relatively planar, as in the eukaryotic translation initiation factor 4E (eIF4E) protein. eIF4E is an oncogene that is overexpressed in numerous forms of cancer, making it a prime target as a therapeutic molecule. We report here the presence of a cryptic pocket at the protein-binding interface of eIF4E, which opens transiently during molecular dynamics simulations of the protein in solvent water and is observed to be stable when solvent water is mixed with benzene molecules. This pocket can also be seen in the ensemble of structures available from the solution-state conformations of eIF4E. The accessibility of the pocket is gated by the side-chain transitions of an evolutionarily conserved tryptophan residue. It is found to be feasible for accommodating clusters of benzene molecules, which signify the plasticity and ligandability of the pocket. We also observe that the newly formed cavity provides a favorable binding environment for interaction of a well-recognized small molecule inhibitor of eIF4E. The occurrence of this transiently accessible cavity highlights the existence of a more pronounced binding groove in a region that has traditionally been considered to be planar. Together, the data suggest that an alternate binding cavity exists on eIF4E and could be exploited for the rational design and development of a new class of lead compounds against the protein.

Bioremediation of uranium-bearing wastewater: Biochemical and chemical factors influencing bioprocess application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Macaskie, L.E.; Yong, P.; Doyle, T.C.

1997-01-05

A biotechnological process for the removal of heavy metals from aqueous solution utilizes enzymatically liberated phosphate ligand which precipitates with heavy metals (M) as cell-bound MHPO{sub 4}. The enzyme, a phosphatase, obeys Michaelis-Menten kinetics in resting and immobilized cells; an integrated form of the Michaelis-Menten equation was used to calculate the apparent K{sub m} (K{sub m app}) as operating in immobilized cells in flow-through columns by a ratio method based on the use of two enzyme loadings (E{sub o1}, E{sub o2}) or two input substrate concentrations (S{sub o1}, S{sub o2}). The calculated K{sub m app} (4.08 mM) was substituted intomore » an equation to describe the removal of metals by immobilized cells. In operation the activity of the bioreactor was in accordance with that predicted mathematically, within 10%. The initial tests were done at neutral pH, whereas the pH of industrial wastewaters is often low; an increase in the K{sub m app} at low pH was found in previous studies. Immobilized cells were challenged with acidic mine drainage wastewaters, where the limiting factors were chemical and not biochemical. Bioreactors initially lost activity in this water, but recovered to remove uranyl ion with more than 70% efficiency under steady-state conditions in the presence of competing cations and anions. Possible reasons for the bioreactor recovery are chemical crystallization factors.« less

Resistance to Plum pox virus strain C in Arabidopsis thaliana and Chenopodium foetidum involves genome-linked viral protein and other viral determinants and might depend on compatibility with host translation initiation factors.

PubMed

Calvo, María; Martínez-Turiño, Sandra; García, Juan Antonio

2014-11-01

Research performed on model herbaceous hosts has been useful to unravel the molecular mechanisms that control viral infections. The most common Plum pox virus (PPV) strains are able to infect Nicotiana species as well as Chenopodium and Arabidopsis species. However, isolates belonging to strain C (PPV-C) that have been adapted to Nicotiana spp. are not infectious either in Chenopodium foetidum or in Arabidopsis thaliana. In order to determine the mechanism underlying this interesting host-specific behavior, we have constructed chimerical clones derived from Nicotiana-adapted PPV isolates from the D and C strains, which differ in their capacity to infect A. thaliana and C. foetidum. With this approach, we have identified the nuclear inclusion a protein (VPg+Pro) as the major pathogenicity determinant that conditions resistance in the presence of additional secondary determinants, different for each host. Genome-linked viral protein (VPg) mutations similar to those involved in the breakdown of eIF4E-mediated resistance to other potyviruses allow some PPV chimeras to infect A. thaliana. These results point to defective interactions between a translation initiation factor and the viral VPg as the most probable cause of host-specific incompatibility, in which other viral factors also participate, and suggest that complex interactions between multiple viral proteins and translation initiation factors not only define resistance to potyviruses in particular varieties of susceptible hosts but also contribute to establish nonhost resistance.

The human papillomavirus type 16 E6 oncoprotein activates mTORC1 signaling and increases protein synthesis.

PubMed

Spangle, Jennifer M; Münger, Karl

2010-09-01

The mammalian target of rapamycin (mTOR) kinase acts as a cellular rheostat that integrates signals from a variety of cellular signal transduction pathways that sense growth factor and nutrient availability as well as intracellular energy status. It was previously reported that the human papillomavirus type 16 (HPV16) E6 oncoprotein may activate the S6 protein kinase (S6K) through binding and E6AP-mediated degradation of the mTOR inhibitor tuberous sclerosis complex 2 (TSC2) (Z. Lu, X. Hu, Y. Li, L. Zheng, Y. Zhou, H. Jiang, T. Ning, Z. Basang, C. Zhang, and Y. Ke, J. Biol. Chem. 279:35664-35670, 2004; L. Zheng, H. Ding, Z. Lu, Y. Li, Y. Pan, T. Ning, and Y. Ke, Genes Cells 13:285-294, 2008). Our results confirmed that HPV16 E6 expression causes an increase in mTORC1 activity through enhanced phosphorylation of mTOR and activation of downstream signaling pathways S6K and eukaryotic initiation factor binding protein 1 (4E-BP1). However, we did not detect a decrease in TSC2 levels in HPV16 E6-expressing cells. We discovered, however, that HPV16 E6 expression causes AKT activation through the upstream kinases PDK1 and mTORC2 under conditions of nutrient deprivation. We show that HPV16 E6 expression causes an increase in protein synthesis by enhancing translation initiation complex assembly at the 5' mRNA cap and an increase in cap-dependent translation. The increase in cap-dependent translation likely results from HPV16 E6-induced AKT/mTORC1 activation, as the assembly of the translation initiation complex and cap-dependent translation are rapamycin sensitive. Lastly, coexpression of the HPV16 E6 and E7 oncoproteins does not affect HPV16 E6-induced activation of mTORC1 and cap-dependent translation. HPV16 E6-mediated activation of mTORC1 signaling and cap-dependent translation may be a mechanism to promote viral replication under conditions of limited nutrient supply in differentiated, HPV oncoprotein-expressing proliferating cells.

In X. laevis embryos high levels of the anti-apoptotic factor p27BBP/eIF6 are stage-dependently found in BrdU and TUNEL-reactive territories.

PubMed

De Marco, N; Campanella, C; Carotenuto, R

2011-05-01

p27BBP/eIF6 (β4 binding protein/eukaryotic initiation factor 6) is a highly conserved protein necessary for cell life. In adult eIF6 mice, a 50% decrease in the protein levels in all tissues is accompanied by a reduction in cell proliferation only in the liver, fat cells and cultured fibroblasts. During X. laevis embryogenesis expression of p27BBP/eIF6 is abundant in high proliferative territories. However, in Xenopus cell proliferation appears unaffected following p27BBP/eIF6 over-expression or down-regulation. Indeed, p27BBP/eIF6 is an anti-apoptotic factor acting upstream of Bcl2 that reduces endogenous apoptosis. We studied p27BBP/eIF6 protein localization in wild type embryos and compared it to proliferation and apoptosis. At the beginning of embryogenesis, high levels of p27BBP/eIF6, proliferation and apoptosis overlap. In later development stages high proliferation levels are present in the same regions where higher p27BBP/eIF6 expression is observed, while apoptosis does not appear specifically concentrated in the same sites. The higher presence of p27BBP/eIF6 would appear related to an increased need of apoptosis control in the regions where cell death is essential for normal development.

The Initiation Factor TFE and the Elongation Factor Spt4/5 Compete for the RNAP Clamp during Transcription Initiation and Elongation

PubMed Central

Grohmann, Dina; Nagy, Julia; Chakraborty, Anirban; Klose, Daniel; Fielden, Daniel; Ebright, Richard H.; Michaelis, Jens; Werner, Finn

2011-01-01

Summary TFIIE and the archaeal homolog TFE enhance DNA strand separation of eukaryotic RNAPII and the archaeal RNAP during transcription initiation by an unknown mechanism. We have developed a fluorescently labeled recombinant M. jannaschii RNAP system to probe the archaeal transcription initiation complex, consisting of promoter DNA, TBP, TFB, TFE, and RNAP. We have localized the position of the TFE winged helix (WH) and Zinc ribbon (ZR) domains on the RNAP using single-molecule FRET. The interaction sites of the TFE WH domain and the transcription elongation factor Spt4/5 overlap, and both factors compete for RNAP binding. Binding of Spt4/5 to RNAP represses promoter-directed transcription in the absence of TFE, which alleviates this effect by displacing Spt4/5 from RNAP. During elongation, Spt4/5 can displace TFE from the RNAP elongation complex and stimulate processivity. Our results identify the RNAP “clamp” region as a regulatory hot spot for both transcription initiation and transcription elongation. PMID:21777815

Influence of APOE Genotype on Hippocampal Atrophy over Time - An N=1925 Surface-Based ADNI Study

PubMed Central

Li, Bolun; Shi, Jie; Gutman, Boris A.; Baxter, Leslie C.; Thompson, Paul M.; Caselli, Richard J.; Wang, Yalin

2016-01-01

The apolipoprotein E (APOE) e4 genotype is a powerful risk factor for late-onset Alzheimer’s disease (AD). In the Alzheimer’s Disease Neuroimaging Initiative (ADNI) cohort, we previously reported significant baseline structural differences in APOE e4 carriers relative to non-carriers, involving the left hippocampus more than the right—a difference more pronounced in e4 homozygotes than heterozygotes. We now examine the longitudinal effects of APOE genotype on hippocampal morphometry at 6-, 12- and 24-months, in the ADNI cohort. We employed a new automated surface registration system based on conformal geometry and tensor-based morphometry. Among different hippocampal surfaces, we computed high-order correspondences, using a novel inverse-consistent surface-based fluid registration method and multivariate statistics consisting of multivariate tensor-based morphometry (mTBM) and radial distance. At each time point, using Hotelling’s T2 test, we found significant morphological deformation in APOE e4 carriers relative to non-carriers in the full cohort as well as in the non-demented (pooled MCI and control) subjects at each follow-up interval. In the complete ADNI cohort, we found greater atrophy of the left hippocampus than the right, and this asymmetry was more pronounced in e4 homozygotes than heterozygotes. These findings, combined with our earlier investigations, demonstrate an e4 dose effect on accelerated hippocampal atrophy, and support the enrichment of prevention trial cohorts with e4 carriers. PMID:27065111

Differential effects of estradiol on carotid artery inflammation when administered early versus late after surgical menopause.

PubMed

Sophonsritsuk, Areepan; Appt, Susan E; Clarkson, Thomas B; Shively, Carol A; Espeland, Mark A; Register, Thomas C

2013-05-01

The aim of this study was to determine the effects of estrogen therapy (ET) on carotid artery inflammation when initiated early and late relative to surgical menopause. Female cynomolgus macaques consuming atherogenic diets were ovariectomized and randomized to control or oral estradiol (E2; human equivalent dose of 1 mg/d micronized E2) initiated at 1 month (early menopause, n = 24) or 54 months (late menopause, n = 40) after ovariectomy. The treatment period was 8 months. Carotid artery expression of the markers of monocyte/macrophages (CD68 and CD163), dendritic cells (CD83), natural killer cells (neural cell adhesion molecule-1), and interferon-γ was significantly lower in E2-treated animals in the early menopause group but not in the late menopause group (P < 0.05). In contrast, carotid artery transcripts for T-cell markers (CD3, CD4, CD8, and CD25), interleukin-10, type I collagen, monocyte chemoattractant protein-1, matrix metalloproteinase-9, and tumor necrosis factor-α were lower in E2-treated monkeys regardless of menopausal stage (P < 0.05). ET initiated soon after menopause inhibits macrophage accumulation in the carotid artery, an effect that is not observed when E2 is administered after several years of estrogen deficiency. No evidence for pro-inflammatory effects of late ET is observed. The results provide support for the timing hypothesis of postmenopausal ET with implications for the interpretation of outcomes in the Women's Health Initiative.

Does the cerebellum initiate movement?

PubMed

Thach, W T

2014-02-01

Opinion is divided on what the exact function of the cerebellum is. Experiments are summarized that support the following views: (1) the cerebellum is a combiner of multiple movement factors; (2) it contains anatomically fixed permanent focal representation of individual body parts (muscles and segments) and movement modes (e.g., vestibular driven vs. cognitive driven); (3) it contains flexible changing representations/memory of physical properties of the body parts including muscle strength, segment inertia, joint viscosity, and segmental interaction torques (dynamics); (4) it contains mechanisms for learning and storage of the properties in item no. 3 through trial-and-error practice; (5) it provides for linkage of body parts, motor modes, and motordynamics via the parallel fiber system; (6) it combines and integrates the many factors so as to initiate coordinated movements of the many body parts; (7) it is thus enabled to play the unique role of initiating coordinated movements; and (8) this unique causative role is evidenced by the fact that: (a) electrical stimulation of the cerebellum can initiate compound coordinated movements; (b) in naturally initiated compound movements, cerebellar discharge precedes that in downstream target structures such as motor cerebral cortex; and (c) cerebellar ablation abolishes the natural production of compound movements in the awake alert individuals.

Non-injection Drug Use and Injection Initiation Assistance among People Who Inject Drugs in Tijuana, Mexico.

PubMed

Ben Hamida, Amen; Rafful, Claudia; Jain, Sonia; Sun, Shelly; Gonzalez-Zuniga, Patricia; Rangel, Gudelia; Strathdee, Steffanie A; Werb, Dan

2018-02-01

Although most people who inject drugs (PWID) report receiving assistance during injection initiation events, little research has focused on risk factors among PWID for providing injection initiation assistance. We therefore sought to determine the influence of non-injection drug use among PWID on their risk to initiate others. We used generalized estimating equation (GEE) models on longitudinal data among a prospective cohort of PWID in Tijuana, Mexico (Proyecto El Cuete IV), while controlling for potential confounders. At baseline, 534 participants provided data on injection initiation assistance. Overall, 14% reported ever initiating others, with 4% reporting this behavior recently (i.e., in the past 6 months). In a multivariable GEE model, recent non-injection drug use was independently associated with providing injection initiation assistance (adjusted odds ratio [AOR] = 2.42, 95% confidence interval [CI] = 1.39-4.20). Further, in subanalyses examining specific drug types, recent non-injection use of cocaine (AOR = 9.31, 95% CI = 3.98-21.78), heroin (AOR = 4.00, 95% CI = 1.88-8.54), and methamphetamine (AOR = 2.03, 95% CI = 1.16-3.55) were all significantly associated with reporting providing injection initiation assistance. Our findings may have important implications for the development of interventional approaches to reduce injection initiation and related harms. Further research is needed to validate findings and inform future approaches to preventing entry into drug injecting.

Reprogramming of non-genomic estrogen signaling by the stemness factor SOX2 enhances the tumor-initiating capacity of breast cancer cells.

PubMed

Vazquez-Martin, Alejandro; Cufí, Sílvia; López-Bonet, Eugeni; Corominas-Faja, Bruna; Cuyàs, Elisabet; Vellon, Luciano; Iglesias, Juan Manuel; Leis, Olatz; Martín, Angel G; Menendez, Javier A

2013-11-15

The restoration of pluripotency circuits by the reactivation of endogenous stemness factors, such as SOX2, may provide a new paradigm in cancer development. The tumoral stem cell reprogramming hypothesis, i.e., the ability of stemness factors to redirect normal and differentiated tumor cells toward a less-differentiated and stem-like state, adds new layers of complexity to cancer biology, because the effects of such reprogramming may remain dormant until engaged later in response to (epi)genetic and/or (micro)environmental events. To test this hypothesis, we utilized an in vitro model of a SOX2-overexpressing cancer stem cell (CSC)-like cellular state that was recently developed in our laboratory by employing Yamanaka's nuclear reprogramming technology in the estrogen receptor α (ERα)-positive MCF-7 breast cancer cell line. Despite the acquisition of distinct molecular features that were compatible with a breast CSC-like cellular state, such as strong aldehyde dehydrogenase activity, as detected by ALDEFLUOR, and overexpression of the SSEA-4 and CD44 breast CSC markers, the tumor growth-initiating ability of SOX2-overexpressing CSC-like MCF-7 cells solely occurred in female nude mice supplemented with estradiol when compared with MCF-7 parental cells. Ser118 phosphorylation of estrogen receptor α (ERα), which is a pivotal integrator of the genomic and nongenomic E 2/ERα signaling pathways, drastically accumulated in nuclear speckles in the interphase nuclei of SOX2-driven CSC-like cell populations. Moreover, SOX2-positive CSC-like cells accumulated significantly higher numbers of actively dividing cells, and the highest levels of phospho-Ser118-ERα occurred when chromosomes lined up on a metaphase plate. The previously unrecognized link between E 2/ERα signaling and SOX2-driven stem cell circuitry may significantly impact our current understanding of breast cancer initiation and progression, i.e., SOX2 can promote non-genomic E 2 signaling that leads to nuclear phospho-Ser118-ERα, which ultimately exacerbates genomic ER signaling in response to E 2. Because E 2 stimulation has been recently shown to enhance breast tumor-initiating cell survival by downregulating miR-140, which targets SOX2, the establishment of a bidirectional cross-talk interaction between the stem cell self-renewal regulator, SOX2, and the local and systemic ability of E 2 to increase breast CSC activity may have profound implications for the development of new CSC-directed strategies for breast cancer prevention and therapy.

Transcriptional and translational control of ornithine decarboxylase during Ras transformation.

PubMed Central

Shantz, Lisa M

2004-01-01

ODC (ornithine decarboxylase) activity is induced following ras activation. However, the Ras effector pathways responsible are unknown. These experiments used NIH-3T3 cells expressing partial-loss-of-function Ras mutants to activate selectively pathways downstream of Ras and examined the contribution of each pathway to ODC induction. Overexpression of Ras12V, a constitutively active mutant, resulted in ODC activities up to 20-fold higher than controls. Stable transfections of Ras partial-loss-of-function mutants and constitutively active forms of MEK (MAPK kinase) and Akt indicated that activation of more than one Ras effector pathway is necessary for the complete induction of ODC activity. The increase in ODC activity in Ras12V-transformed cells is not owing to a substantial change in ODC protein half-life, which increased by <2-fold. Northern-blot analysis and reporter assays suggested that the mechanism of ODC induction involves both a modest increase in the transcription of ODC mRNA and a much more considerable increase in the translation of mRNA into protein. ODC transcription was controlled through a pathway dependent on Raf/MEK/ERK (where ERK stands for extracellular-signal-regulated kinase) activation, whereas activation of the phosphoinositide 3-kinase and the Raf/MEK/ERK pathways were necessary for translational regulation of ODC. The increase in ODC synthesis was accompanied by changes in phosphorylation of eukaryotic initiation factor 4E and its binding protein 4E-BP1. Results show that the phosphoinositide 3-kinase pathway regulates phosphorylation of both proteins, whereas the Raf/MEK/ERK pathway affects only the eukaryotic initiation factor 4E phosphorylation. PMID:14519103

Risk factors for development of dementia in a unique six-year cohort study. I. An exploratory, pilot study of involvement of the E4 allele of apolipoprotein E, mutations of the hemochromatosis-HFE gene, type 2 diabetes, and stroke.

PubMed

Percy, Maire; Somerville, Martin J; Hicks, Mark; Garcia, Angeles; Colelli, Teresa; Wright, Emily; Kitaygorodsky, Julia; Jiang, Amy; Ho, Valerie; Parpia, Alyssa; Wong, Michael K

2014-01-01

Risk factors for dementia development are not well-defined. We evaluated several factors alone and in combination in a unique cohort of Caucasian volunteers over an approximately 6-year observation window using a nested case/control design. Factors included: apolipoprotein E (ApoE) gene variants (the E4 allele is the strongest confirmed genetic predisposing factor for Alzheimer's disease), the hemochromatosis-HFE gene mutations (H63D and C282Y), diabetes, and stroke. At study entry, subjects were ≥65 years of age (M ± SD = 73.0 ± 4.9), had an MMSE score ≥24, and no evidence of cerebrovascular disease or current depression. Genotyping was completed on 163 available DNA samples from three different groups at the study end: those who still had normal cognitive function; those who had developed dementia; and those with Mild Cognitive Impairment (MCI). Analyses were interpreted at the 95% confidence level without Bonferroni corrections. In the subgroup with dementia, all cases of diabetes were type 2 and present at study entry, whereas all strokes occurred during the study. The results highlight apparently synergistic interactions between genetic and medical risk factors for dementia development, gender differences in risk factors, and involvement of HFE mutations. Having E4 (i.e., either of E3/4 or E4/4), C282Y, H63D, diabetes, or stroke alone did not attain significance. Significant predisposing factors with post-hoc power ≥80% were: E4 homozygosity (E4/4)males+females, odds ratio (OR) = 56.0); E4+diabetes (males+females, OR = 13.7; E4+H63D+diabetes (females, OR = 52.0); E4+stroke (males, OR = 46.5). The importance of preventing diabetes and stroke to ward off dementia and the possible role of iron dysmetabolism in dementia are discussed.

Does provision of point-of-care CD4 technology and early knowledge of CD4 levels affect early initiation and retention on antiretroviral treatment in HIV-positive pregnant women in the context of Option B+ for PMTCT?

PubMed

Mangwiro, Alexio-Zambezi; Makomva, Kudzai; Bhattacharya, Antoinette; Bhattacharya, Gaurav; Gotora, Tendai; Owen, Mila; Mushavi, Angela; Mangwanya, Douglas; Zinyowera, Sekesai; Rusakaniko, Simbarashe; Mugurungi, Owen; Zizhou, Simukai; Busumani, William; Masuka, Nyasha

2014-11-01

Evidence for Elimination (E4E) is a collaborative project established in 2012 as part of the INSPIRE (INtegrating and Scaling up PMTCT through Implementation REsearch) initiative. E4E is a cluster-randomized trial with 2 arms; Standard of care and "POC Plus" [in which point-of-care (POC) CD4 devices and related counseling support are provided]; aimed at improving retention-in-care of HIV-infected pregnant women and mothers. In November 2013, Zimbabwe adopted Option B+ for HIV-positive pregnant women under which antiretroviral treatment eligibility is no longer based on CD4 count. However, Ministry of Health and Child Care guidelines still require baseline and 6-monthly CD4 testing for treatment monitoring, until viral load testing becomes widely available. Considering the current limited capacity for viral-load testing, the significant investments in CD4 testing already made and the historical reliance on CD4 by health care workers for determining eligibility for antiretroviral treatment, E4E seeks to compare the impact of the provision of POC CD4 technology and early knowledge of CD4 levels on retention-in-care at 12 months, with the current standard of routine, laboratory-based CD4 testing. The study also compares rates of initiation and time-to-initiation between the 2 arms and according to level of maternal CD4 count, the cost of retaining HIV-positive pregnant women in care and the acceptability and feasibility of POC CD4 in the context of Option B+. Outcome measures are derived from routine health systems data. E4E will provide data on POC CD4 testing and retention-in-care associated with Option B+ and serve as an early learning platform to inform implementation of Option B+ in Zimbabwe.

KLF4 Nuclear Export Requires ERK Activation and Initiates Exit from Naive Pluripotency.

PubMed

Dhaliwal, Navroop K; Miri, Kamelia; Davidson, Scott; Tamim El Jarkass, Hala; Mitchell, Jennifer A

2018-04-10

Cooperative action of a transcription factor complex containing OCT4, SOX2, NANOG, and KLF4 maintains the naive pluripotent state; however, less is known about the mechanisms that disrupt this complex, initiating exit from pluripotency. We show that, as embryonic stem cells (ESCs) exit pluripotency, KLF4 protein is exported from the nucleus causing rapid decline in Nanog and Klf4 transcription; as a result, KLF4 is the first pluripotency transcription factor removed from transcription-associated complexes during differentiation. KLF4 nuclear export requires ERK activation, and phosphorylation of KLF4 by ERK initiates interaction of KLF4 with nuclear export factor XPO1, leading to KLF4 export. Mutation of the ERK phosphorylation site in KLF4 (S132) blocks KLF4 nuclear export, the decline in Nanog, Klf4, and Sox2 mRNA, and differentiation. These findings demonstrate that relocalization of KLF4 to the cytoplasm is a critical first step in exit from the naive pluripotent state and initiation of ESC differentiation. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Quantitative studies of mRNA recruitment to the eukaryotic ribosome.

PubMed

Fraser, Christopher S

2015-07-01

The process of peptide bond synthesis by ribosomes is conserved between species, but the initiation step differs greatly between the three kingdoms of life. This is illustrated by the evolution of roughly an order of magnitude more initiation factor mass found in humans compared with bacteria. Eukaryotic initiation of translation is comprised of a number of sub-steps: (i) recruitment of an mRNA and initiator methionyl-tRNA to the 40S ribosomal subunit; (ii) migration of the 40S subunit along the 5' UTR to locate the initiation codon; and (iii) recruitment of the 60S subunit to form the 80S initiation complex. Although the mechanism and regulation of initiation has been studied for decades, many aspects of the pathway remain unclear. In this review, I will focus discussion on what is known about the mechanism of mRNA selection and its recruitment to the 40S subunit. I will summarize how the 43S preinitiation complex (PIC) is formed and stabilized by interactions between its components. I will discuss what is known about the mechanism of mRNA selection by the eukaryotic initiation factor 4F (eIF4F) complex and how the selected mRNA is recruited to the 43S PIC. The regulation of this process by secondary structure located in the 5' UTR of an mRNA will also be discussed. Finally, I present a possible kinetic model with which to explain the process of mRNA selection and recruitment to the eukaryotic ribosome. Copyright © 2015 Elsevier B.V. and Société française de biochimie et biologie Moléculaire (SFBBM). All rights reserved.

Factors associated with antiretroviral treatment initiation amongst HIV-positive individuals linked to care within a universal test and treat programme: early findings of the ANRS 12249 TasP trial in rural South Africa

PubMed Central

Boyer, Sylvie; Iwuji, Collins; Gosset, Andréa; Protopopescu, Camelia; Okesola, Nonhlanhla; Plazy, Mélanie; Spire, Bruno; Orne-Gliemann, Joanna; McGrath, Nuala; Pillay, Deenan; Dabis, François; Larmarange, Joseph

2016-01-01

Prompt uptake of antiretroviral treatment (ART) is essential to ensure the success of universal test and treat (UTT) strategies to prevent HIV transmission in high-prevalence settings. We describe ART initiation rates and associated factors within an ongoing UTT cluster-randomized trial in rural South Africa. HIV-positive individuals were offered immediate ART in the intervention arm vs. national guidelines recommended initiation (CD4≤350 cells/mm3) in the control arm. We used data collected up to July 2015 among the ART-eligible individuals linked to TasP clinics before January 2015. ART initiation rates at one (M1), three (M3) and six months (M6) from baseline visit were described by cluster and CD4 count strata (cells/mm3) and other eligibility criteria: ≤100; 100–200; 200–350; CD4>350 with WHO stage 3/4 or pregnancy; CD4>350 without WHO stage 3/4 or pregnancy. A Cox model accounting for covariate effect changes over time was used to assess factors associated with ART initiation. The 514 participants had a median [interquartile range] follow-up duration of 1.08 [0.69; 2.07] months until ART initiation or last visit. ART initiation rates at M1 varied substantially (36.9% in the group CD4>350 without WHO stage 3/4 or pregnancy, and 55.2–71.8% in the three groups with CD4≤350) but less at M6 (from 85.3% in the first group to 96.1–98.3% in the three other groups). Factors associated with lower ART initiation at M1 were a higher CD4 count and attending clinics with both high patient load and higher cluster HIV prevalence. After M1, having a regular partner was the only factor associated with higher likelihood of ART initiation. These findings suggest good ART uptake within a UTT setting, even among individuals with high CD4 count. However, inadequate staffing and healthcare professional practices could result in prioritizing ART initiation in patients with the lowest CD4 counts. PMID:27421051

A new MIF4G domain-containing protein, CTIF, directs nuclear cap-binding protein CBP80/20-dependent translation

PubMed Central

Kim, Kyoung Mi; Cho, Hana; Choi, Kobong; Kim, Jaedong; Kim, Bong-Woo; Ko, Young-Gyu; Jang, Sung Key; Kim, Yoon Ki

2009-01-01

During or right after mRNA export via the nuclear pore complex (NPC) in mammalian cells, mRNAs undergo translation mediated by nuclear cap-binding proteins 80 and 20 (CBP80/20). After CBP80/20-dependent translation, CBP80/20 is replaced by cytoplasmic cap-binding protein eIF4E, which directs steady-state translation. Nonsense-mediated mRNA decay (NMD), one of the best-characterized mRNA surveillance mechanisms, has been shown to occur on CBP80/20-bound mRNAs. However, despite the tight link between CBP80/20-dependent translation and NMD, the underlying molecular mechanism and cellular factors that mediate CBP80/20-dependent translation remain obscure. Here, we identify a new MIF4G domain-containing protein, CTIF (CBP80/20-dependent translation initiation factor). CTIF interacts directly with CBP80 and is part of the CBP80/20-dependent translation initiation complex. Depletion of endogenous CTIF from an in vitro translation system selectively blocks the translation of CBP80-bound mRNAs, while addition of purified CTIF restores it. Accordingly, down-regulation of endogenous CTIF abrogates NMD. Confocal microscopy shows that CTIF is localized to the perinuclear region. Our observations demonstrate the existence of CBP80/20-dependent translation and support the idea that CBP80/20-dependent translation is mechanistically different from steady-state translation through identification of a specific cellular protein, CTIF. PMID:19648179

Development of a framework towards successful implementation of e-governance initiatives in health sector in India.

PubMed

Ray, Subhasis; Mukherjee, Amitava

2007-01-01

The purpose of this paper is to explore the route map for employing efficient e-governance so that at least existing resource and infrastructure are better utilized and deficiencies are tracked for future planning. National health is one of the most important factors in a country's economic growth. India seems to be a victim of the vicious cycle around poor economy and poor health conditions. A detailed study was carried out to find out India's healthcare infrastructure and its standing in e-governance initiatives. After consolidating the fact that effective e-governance can enhance the quality of healthcare service even within limited resources, authors explored success and failure factors of many e-governance initiatives in India and abroad. Finally, an e-governance framework is suggested based on the above factors together with the authors' own experience of implementing e-governance projects in India and abroad. The suggested framework is based on a phased implementation approach. The first phase "Information Dissemination" is more geared towards breaking the "digital divide" across three dimensions: G2Business; G2Citizen; and G2Agent. The most advanced stage is aimed towards joining up healthcare information across the above three dimensions and drawing meaningful analytics out of it. The recommendations also include management of Policies, Scope, Process Reform, Infrastructure, Technology, Finance, Partnership and People for efficient implementation of such e-governance initiatives. The paper provides measures for continuous evaluation of systems as one passes through various stages of implementation. However, the framework can be tested on real or simulated environment to prove its worthiness. This paper can be a potential frame of reference for nation-wide e-healthcare projects not only in India but also in other developing countries. The paper also describes challenges that are most likely to be faced during implementation. Since the paper is practical in nature, the real appeal will be to practitioners who are responsible for implementation of large e-governance initiatives for improving healthcare services.

Engineering of CRISPR/Cas9-mediated potyvirus resistance in transgene-free Arabidopsis plants.

PubMed

Pyott, Douglas E; Sheehan, Emma; Molnar, Attila

2016-10-01

Members of the eukaryotic translation initiation factor (eIF) gene family, including eIF4E and its paralogue eIF(iso)4E, have previously been identified as recessive resistance alleles against various potyviruses in a range of different hosts. However, the identification and introgression of these alleles into important crop species is often limited. In this study, we utilise CRISPR/Cas9 technology to introduce sequence-specific deleterious point mutations at the eIF(iso)4E locus in Arabidopsis thaliana to successfully engineer complete resistance to Turnip mosaic virus (TuMV), a major pathogen in field-grown vegetable crops. By segregating the induced mutation from the CRISPR/Cas9 transgene, we outline a framework for the production of heritable, homozygous mutations in the transgene-free T2 generation in self-pollinating species. Analysis of dry weights and flowering times for four independent T3 lines revealed no differences from wild-type plants under standard growth conditions, suggesting that homozygous mutations in eIF(iso)4E do not affect plant vigour. Thus, the established CRISPR/Cas9 technology provides a new approach for the generation of Potyvirus resistance alleles in important crops without the use of persistent transgenes. © 2016 The Authors. Molecular Plant Pathology Published by British Society for Plant Pathology and John Wiley & Sons Ltd.

What determines whether mammalian ribosomes resume scanning after translation of a short upstream open reading frame?

PubMed Central

Pöyry, Tuija A.A.; Kaminski, Ann; Jackson, Richard J.

2004-01-01

If the 5′-proximal AUG triplet in a mammalian mRNA is followed by a short open reading frame (sORF), a significant fraction of ribosomes resume scanning after termination of sORF translation, and reinitiate at a downstream AUG. To examine the underlying mechanism, we examined reinitiation in vitro using a series of mRNAs that differed only in the 5′-untranslated region (UTR). Efficient reinitiation was found to occur only if the eIF4F complex, or at a minimum the central one-third fragment of eIF4G, participated in the primary initiation event at the sORF initiation codon. It did not occur, however, when sORF translation was driven by the classical swine fever virus or cricket paralysis virus internal ribosome entry sites (IRESs), which do not use eIF4A, 4B, 4E, or 4G. A critical test was provided by an mRNA with an unstructured 5′-UTR, which is translated by scanning but does not absolutely need eIF4G and eIF4A: There was efficient reinitiation in a standard reticulocyte lysate, when initiation would be largely driven by eIF4F, but no reinitiation in an eIF4G-depleted lysate. These results suggest that resumption of scanning may depend on the interaction between eIF4F (or the eIF4G central domain) and the ribosome being maintained while the ribosome translates the sORF. PMID:14701882

Estetrol, a Fetal Selective Estrogen Receptor Modulator, Acts on the Vagina of Mice through Nuclear Estrogen Receptor α Activation.

PubMed

Benoit, Thibaut; Valera, Marie-Cecile; Fontaine, Coralie; Buscato, Melissa; Lenfant, Francoise; Raymond-Letron, Isabelle; Tremollieres, Florence; Soulie, Michel; Foidart, Jean-Michel; Game, Xavier; Arnal, Jean-Francois

2017-11-01

The genitourinary syndrome of menopause has a negative impact on quality of life of postmenopausal women. The treatment of vulvovaginal atrophy includes administration of estrogens. However, oral estrogen treatment is controversial because of its potential risks on venous thrombosis and breast cancer. Estetrol (E4) is a natural estrogen synthesized exclusively during pregnancy by the human fetal liver and initially considered as a weak estrogen. However, E4 was recently evaluated in phase 1 to 2 clinical studies and found to act as an oral contraceptive in combination with a progestin, without increasing the level of coagulation factors. We recently showed that E4 stimulates uterine epithelial proliferation through nuclear estrogen receptor (ER) α, but failed to elicit endothelial responses. Herein, we first evaluated the morphological and functional impacts of E4 on the vagina of ovariectomized mice, and we determined the molecular mechanism mediating these effects. Vaginal epithelial proliferation and lubrication after stimulation were found to increase after E4 chronic treatment. Using a combination of pharmacological and genetic approaches, we demonstrated that these E4 effects on the vagina are mediated by nuclear ERα activation. Altogether, we demonstrate that the selective activation of nuclear ERα is both necessary and sufficient to elicit functional and structural effects on the vagina, and therefore E4 appears promising as a therapeutic option to improve vulvovaginal atrophy. Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Phosphorylation of translation factors in response to anoxia in turtles, Trachemys scripta elegans: role of the AMP-activated protein kinase and target of rapamycin signalling pathways.

PubMed

Rider, Mark H; Hussain, Nusrat; Dilworth, Stephen M; Storey, Kenneth B

2009-12-01

Long-term survival of oxygen deprivation by animals with well-developed anoxia tolerance depends on multiple biochemical adaptations including strong metabolic rate depression. We investigated whether the AMP-activated protein kinase (AMPK) could play a regulatory role in the suppression of protein synthesis that occurs when turtles experience anoxic conditions. AMPK activity and the phosphorylation state of ribosomal translation factors were measured in liver, heart, red muscle and white muscle of red-eared slider turtles (Trachemys scripta elegans) subjected to 20 h of anoxic submergence. AMPK activity increased twofold in white muscle of anoxic turtles compared with aerobic controls but remained unchanged in liver and red muscle, whereas in heart AMPK activity decreased by 40%. Immunoblotting with phospho-specific antibodies revealed that eukaryotic elongation factor-2 phosphorylation at the inactivating Thr56 site increased six- and eightfold in red and white muscles from anoxic animals, respectively, but was unchanged in liver and heart. The phosphorylation state of the activating Thr389 site of p70 ribosomal protein S6 kinase was reduced under anoxia in red muscle and heart but was unaffected in liver and white muscle. Exposure to anoxia decreased 40S ribosomal protein S6 phosphorylation in heart and promoted eukaryotic initiation factor 4E-binding protein-1 (4E-BP1) dephosphorylation in red muscle, but surprisingly increased 4E-BP1 phosphorylation in white muscle. The changes in phosphorylation state of translation factors suggest that organ-specific patterns of signalling and response are involved in achieving the anoxia-induced suppression of protein synthesis in turtles.

Investigation of Room Temperature Mössbauer Spectroscopy and Initial Permeability Properties of Al3+ Substituted Cobalt Ferrites

NASA Astrophysics Data System (ADS)

Pandit, Rabia; Kaur, Pawanpreet; Sharma, K. K.; Hashim, Mohd.; Kumar, Ravi

In the present work, Al3+ substituted cobalt ferrites (CoFe2‑xAlxO4, x=0.2, 0.4, 0.6, 0.8) have been synthesized via standard solid-state reaction technique. The incorporation of Al3+ ions in cobalt ferrite has been shown to play an important role in modifying the magnetic properties. The room temperature (300K) 57Fe Mössbauer spectra reveals that the studied samples show two characteristic ferromagnetic zeeman sextets at A and B-sites at lower Al3+ ion concentration (i.e., up to x=0.4). However, a paramagnetic relaxation has been noted for higher Al3+ substitution (for x=0.6 and 0.8) samples. The dependence of the Mössbauer parameters such as isomer shift, quadrupole splitting, line width and magnetic hyperfine field on Al3+ ion concentration has also been noted. The variations in initial permeability over a wide frequency range (125kHz to 30MHz) at 300K have been recorded. The fairly constant values of initial permeability and the low values of the relative loss factor of the order of 10‑4 to 10‑5 over the wide frequency range are the important findings of the present work. The observed low values of relative loss factor at high frequencies suggest that the studied ferrites are promising materials to be used in microwave applications.

Assessing corporate social responsibility in China's sports lottery administration and its influence on consumption behavior.

PubMed

Li, Hai; Zhang, James J; Mao, Luke Lunhua; Min, Sophia D

2012-09-01

The purpose of this study was to identify and examine consumer perception of corporate social responsibility (CSR) in China's sports lottery industry, and the effect of perceived CSR initiatives on sports lottery consumption behavior. Research participants (N = 4,980), selected based on a computer-generated, randomly stratified multistage sampling process, comprised Chinese residents who had purchased sports lottery tickets in the past 12 months. They completed a questionnaire that was derived from a qualitative research process. A factor analysis extracted two factors associated with perceptions of CSR in China's sports lottery administration: Regulatory and Prevention Responsibilities and Product Development Responsibility. Logistic regression analyses revealed that these two factors were influential of consumer behavior (i.e., relative and absolute expenditure, purchasing frequency, and time commitment). This study represents an initial effort to understand the dimensions of perceived CSR associated with Chinese sports lottery. The findings signify the importance of enforcing CSR in sports lottery administration.

Cannabinoid Modulation of Eukaryotic Initiation Factors (eIF2α and eIF2B1) and Behavioral Cross-Sensitization to Cocaine in Adolescent Rats.

PubMed

Melas, Philippe A; Qvist, Johanna S; Deidda, Matteo; Upreti, Chirag; Wei, Ya Bin; Sanna, Fabrizio; Fratta, Walter; Scherma, Maria; Fadda, Paola; Kandel, Denise B; Kandel, Eric R

2018-03-13

Reduced eukaryotic Initiation Factor 2 (eIF2)α phosphorylation (p-eIF2α) enhances protein synthesis, memory formation, and addiction-like behaviors. However, p-eIF2α has not been examined with regard to psychoactive cannabinoids and cross-sensitization. Here, we find that a cannabinoid receptor agonist (WIN 55,212-2 mesylate [WIN]) reduced p-eIF2α in vitro by upregulating GADD34 (PPP1R15A), the recruiter of protein phosphatase 1 (PP1). The induction of GADD34 was linked to ERK/CREB signaling and to CREB-binding protein (CBP)-mediated histone hyperacetylation at the Gadd34 locus. In vitro, WIN also upregulated eIF2B1, an eIF2 activator subunit. We next found that WIN administration in vivo reduced p-eIF2α in the nucleus accumbens of adolescent, but not adult, rats. By contrast, WIN increased dorsal striatal levels of eIF2B1 and ΔFosB among both adolescents and adults. In addition, we found cross-sensitization between WIN and cocaine only among adolescents. These findings show that cannabinoids can modulate eukaryotic initiation factors, and they suggest a possible link between p-eIF2α and the gateway drug properties of psychoactive cannabinoids. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

BRAF-mutated cells activate GCN2-mediated integrated stress response as a cytoprotective mechanism in response to vemurafenib.

PubMed

Nagasawa, Ikuko; Kunimasa, Kazuhiro; Tsukahara, Satomi; Tomida, Akihiro

2017-01-22

In BRAF-mutated melanoma cells, the BRAF inhibitor, vemurafenib, induces phosphorylation of eukaryotic initiation factor 2α (eIF2α) and subsequent induction of activating transcription factor 4 (ATF4), the central regulation node of the integrated stress response (ISR). While the ISR supports cellular adaptation to various stresses, the role of vemurafenib-triggered ISR has not been fully characterized. Here, we showed that in response to vemurafenib, BRAF-mutated melanoma and colorectal cancer cells rapidly induced the ISR as a cytoprotective mechanism through activation of general control nonderepressible 2 (GCN2), an eIF2α kinase sensing amino acid levels. The vemurafenib-triggered ISR, an event independent of downstream MEK inhibition, was specifically prevented by silencing GCN2, but not other eIF2α kinases, including protein kinase-like endoplasmic reticulum kinase, which transmits endoplasmic reticulum (ER) stress. Consistently, the ER stress gatekeeper, GRP78, was not induced by vemurafenib. Interestingly, ATF4 silencing by siRNA rendered BRAF-mutated melanoma cells sensitive to vemurafenib. Thus, the GCN2-mediated ISR can promote cellular adaptation to vemurafenib-induced stress, providing an insight into the development of drug resistance. Copyright © 2016 Elsevier Inc. All rights reserved.

Factors associated with initial incomplete ablation for benign thyroid nodules after radiofrequency ablation: First results of CEUS evaluation.

PubMed

Zhao, Chong-Ke; Xu, Hui-Xiong; Lu, Feng; Sun, Li-Ping; He, Ya-Ping; Guo, Le-Hang; Li, Xiao-Long; Bo, Xiao-Wan; Yue, Wen-Wen

2017-01-01

To assess the factors associated with initial incomplete ablation (ICA) after radiofrequency ablation for benign thyroid nodules (BTNs). 69 BTNs (mean volume 6.35±5.66 ml, range 1.00-25.04 ml) confirmed by fine-needle aspiration cytology (FNAC) in fifty-four patients were treated with ultrasound-guided percutaneous radiofrequency ablation (RFA) and the local treatment efficacy was immediately assessed by intra-procedural contrast-enhanced ultrasound (CEUS). The RFA was performed with a bipolar electrode (CelonProSurge 150-T20, output power: 20 W). CEUS was performed with a second generation contrast agent under low acoustic power (i.e. coded phase inversion, CPI). Characteristics of clinical factors, findings on conventional gray-scale ultrasound, color-Doppler ultrasound, and CEUS were evaluated preoperatively. Factors associated with initial ICA and initial ICA patterns on CEUS were assessed. Volume reduction ratios (VRRs) of ICA nodules were compared with those with complete ablation (CA). The RFA procedures were accomplished with a mean ablation time and mean total energy deposition of 11.13±3.39 min (range, 5.38-22.13 min) and 12612±4466 J (range, 6310-26130 J) respectively. CEUS detected initial ICA in 21 of 69 (30.8%) BTNs and 16 (76.2%) of the 21 BTNs with initial ICA achieved CA after additional RFA, leading to a final CA rate of 92.8% (64/69). The factors associated with initial ICA were predominantly solid nodule, nodule close to danger triangle area, nodule close to carotid artery, and peripheral blood flow on color-Doppler ultrasound (all P < 0.05). The mean VRRs of all BTNs were 23.4%, 54.4% and 81.9% at the 1-, 3- and 6-month follow-up, respectively. All BTNs achieved therapeutic success in this series in that all had VRRs of >50% at the 6-month follow-up, among which 7 nodules (10.1%) had VRRs of >90%. There were significant differences in VRRs between ICA nodules and CA nodules at the 3- and 6-month follow-up (all P < 0.05). The factors associated with initial ICA after RFA for BTNs were predominantly solid nodules, nodule close to danger triangle area, nodule close to carotid artery, and peripheral blood flow on color-Doppler ultrasound. CEUS assists quick treatment response evaluation and facilitates subsequent additional RFA and final CA of the nodules. Nodules with CA achieve a better outcome in terms of VRR in comparison with those with ICA.

Prostaglandin E2 produced by Entamoeba histolytica binds to EP4 receptors and stimulates interleukin-8 production in human colonic cells.

PubMed

Dey, Indranil; Chadee, Kris

2008-11-01

Entamoeba histolytica pathogenesis in the colon occurs in a stepwise fashion. It begins with colonization of the mucin layer, which is followed by stimulation of a proinflammatory response that causes nonspecific tissue damage that may facilitate parasite invasion of the underlying colonic mucosa. Unfortunately, the parasite and/or host factors that stimulate a proinflammatory response in the gut are poorly understood. In this study, we found that live E. histolytica or secretory or proteins (SP) and soluble ameba components (SAP) can markedly increase interleukin-8 (IL-8) mRNA expression and protein production in colonic epithelial cells. The IL-8-stimulating molecule produced by live amebae was identified as prostaglandin E(2) (PGE(2)) as trophozoites treated with cyclooxygenase inhibitors inhibited the biosynthesis of PGE(2) and eliminated IL-8 production induced by live parasites or ameba components. Moreover, using specific prostaglandin EP2 and EP4 receptor agonists and antagonists, we found that PGE(2) binds exclusively through EP4 receptors in colonic epithelial cells to stimulate IL-8 production. Silencing of EP4 receptors with EP4 small interfering RNA completely eliminated SP- and SAP-induced IL-8 production. These studies identified bioactive PGE(2) as a one of the major virulence factors produced by E. histolytica that can stimulate the potent neutrophil chemokine and activator IL-8, which can trigger an acute host inflammatory response. Thus, the induction of IL-8 production in response to E. histolytica-derived PGE(2) may be a mechanism that explains the initiation and amplification of acute inflammation associated with intestinal amebiasis.

HCV Treatment Initiation in Patients with Chronic Kidney Disease: Results from ERCHIVES

PubMed Central

Butt, Adeel; Ren, Yanjie; Puenpatom, Amy; Arduino, Jean Marie; Kumar, Ritesh; Abou-Samra, Abdul-Badi

2017-01-01

Abstract Background Newer directing antiviral agents against HCV (DAAs) are safe and efficacious in persons with chronic kidney disease (CKD). Whether availability of these newer DAAs has resulted in more persons with CKD initiating HCV treatment remains unknown. Methods We identified HCV+ persons in ERCHIVES. We excluded HIV+ and HBsAg+ and those with missing HCV RNA and eGFR data. We determined the CKD stage according to National Kidney Foundation criteria. We determined the number of persons initiated on any of the approved DAA-regimen (defined as >14 days of DAA prescription). Logistic regression analyses was used to determine factors associated with treatment initiation. Results Among 76,513 evaluable persons, 21.1% initiated DAA treatment. Initiation rates differed significantly by CKD stage: 21.1% (15,136/68,469) for eGFR>90mL/minute/1.73m2 and CKD stage-2; 14.0% 9853/6,086) for CKD stage 3; and 7.6% (148/1,958) for CKD stage-4/5. Those with CKD stage-3 were 35% less likely and those with CKD stage-4/5 were 65% less likely to initiate treatment with a DAA compared with those with baseline eGFR>90mL/minute/1.73m2. Those with Body Mass Index (BMI)>30 were more likely to initiate treatment (OR 1.24, 95% CI 1.19,1.29). Treatment initiation was less likely in HCV genotype 2 or 3 and those with diabetes (OR 0.82, 95% CI 0.78,0.86), cardiovascular disease (OR 0.73, 95% CI 0.68,0.78), alcohol abuse or dependence (OR 0.75, 95% CI 0.72,0.78) or cirrhosis (OR 0.85, 95% CI 0.80,0.89) at baseline. Conclusion Persons with more advanced CKD are less likely to receive treatment for HCV. Strategies are needed to improve treatment rates in the HCV/CKD population. Disclosures A. Butt, Merck: Investigator, Grant recipient. A. Puenpatom, Merck: Employee, Salary. J. M. Arduino, Merck: Employee, Salary. R. Kumar, Merck: Employee, Salary

Archaeal TFEα/β is a hybrid of TFIIE and the RNA polymerase III subcomplex hRPC62/39

PubMed Central

Blombach, Fabian; Salvadori, Enrico; Fouqueau, Thomas; Yan, Jun; Reimann, Julia; Sheppard, Carol; Smollett, Katherine L; Albers, Sonja V; Kay, Christopher WM; Thalassinos, Konstantinos; Werner, Finn

2015-01-01

Transcription initiation of archaeal RNA polymerase (RNAP) and eukaryotic RNAPII is assisted by conserved basal transcription factors. The eukaryotic transcription factor TFIIE consists of α and β subunits. Here we have identified and characterised the function of the TFIIEβ homologue in archaea that on the primary sequence level is related to the RNAPIII subunit hRPC39. Both archaeal TFEβ and hRPC39 harbour a cubane 4Fe-4S cluster, which is crucial for heterodimerization of TFEα/β and its engagement with the RNAP clamp. TFEα/β stabilises the preinitiation complex, enhances DNA melting, and stimulates abortive and productive transcription. These activities are strictly dependent on the β subunit and the promoter sequence. Our results suggest that archaeal TFEα/β is likely to represent the evolutionary ancestor of TFIIE-like factors in extant eukaryotes. DOI: http://dx.doi.org/10.7554/eLife.08378.001 PMID:26067235

Novel insights into the architecture and protein interaction network of yeast eIF3.

PubMed

Khoshnevis, Sohail; Hauer, Florian; Milón, Pohl; Stark, Holger; Ficner, Ralf

2012-12-01

Translation initiation in eukaryotes is a multistep process requiring the orchestrated interaction of several eukaryotic initiation factors (eIFs). The largest of these factors, eIF3, forms the scaffold for other initiation factors, promoting their binding to the 40S ribosomal subunit. Biochemical and structural studies on eIF3 need highly pure eIF3. However, natively purified eIF3 comprise complexes containing other proteins such as eIF5. Therefore we have established in vitro reconstitution protocols for Saccharomyces cerevisiae eIF3 using its five recombinantly expressed and purified subunits. This reconstituted eIF3 complex (eIF3(rec)) exhibits the same size and activity as the natively purified eIF3 (eIF3(nat)). The homogeneity and stoichiometry of eIF3(rec) and eIF3(nat) were confirmed by analytical size exclusion chromatography, mass spectrometry, and multi-angle light scattering, demonstrating the presence of one copy of each subunit in the eIF3 complex. The reconstituted and native eIF3 complexes were compared by single-particle electron microscopy showing a high degree of structural conservation. The interaction network between eIF3 proteins was studied by means of limited proteolysis, analytical size exclusion chromatography, in vitro binding assays, and isothermal titration calorimetry, unveiling distinct protein domains and subcomplexes that are critical for the integrity of the protein network in yeast eIF3. Taken together, the data presented here provide a novel procedure to obtain highly pure yeast eIF3, suitable for biochemical and structural analysis, in addition to a detailed picture of the network of protein interactions within this complex.

Cultural and environmental factors affecting the longevity of Escherichia coli in Histosols.

PubMed

Tate, R L

1978-05-01

The survival of Escherichia coli in organic soils (Histosols) was examined. The death rate of this organism in Pahokee muck was less than that observed in Pompano fine sand. The number of viable E. coli cells found in the muck was approximately threefold greater than that found in the sand following 8 days of incubation. The initial population of the coliform affected the death rate. The rate of loss of viability varied 100-fold when the population size decreased from 2.5 x 10(7) to 3.4 x 10(4). Other factors affecting the viability of E. coli in muck were aerobic versus anaerobic growth of the organism and moist versus flooded conditions in the soil. The greatest survival of the coliform was noted with anaerobically grown cells amended to flooded soil. That the observed decrease in E. coli viability in soil was the result of biotic factors was demonstrated with amendment of sterile soil with E. coli. When 1.1 x 10(5) bacteria per g of soil were added to sterile muck, a population of 3.0 x 10(7) organisms per g of soil developed over a 10-day period. The role of the protozoa in eradication of the coliform from the muck was indicated by a sixfold increase in the protozoan population in natural soil amended with E. coli. Higher organic matter content in a Histosol compared with a mineral soil resulted in an increased survival of the fecal coliforms. Biotic factors are instrumental in the decline in coliform populations, but the potential for growth of the coliform in the organic soil could extend the survival of the organism.

Pharmacological dimerization and activation of the exchange factor eIF2B antagonizes the integrated stress response

PubMed Central

Sidrauski, Carmela; Tsai, Jordan C; Kampmann, Martin; Hearn, Brian R; Vedantham, Punitha; Jaishankar, Priyadarshini; Sokabe, Masaaki; Mendez, Aaron S; Newton, Billy W; Tang, Edward L; Verschueren, Erik; Johnson, Jeffrey R; Krogan, Nevan J; Fraser, Christopher S; Weissman, Jonathan S; Renslo, Adam R; Walter, Peter

2015-01-01

The general translation initiation factor eIF2 is a major translational control point. Multiple signaling pathways in the integrated stress response phosphorylate eIF2 serine-51, inhibiting nucleotide exchange by eIF2B. ISRIB, a potent drug-like small molecule, renders cells insensitive to eIF2α phosphorylation and enhances cognitive function in rodents by blocking long-term depression. ISRIB was identified in a phenotypic cell-based screen, and its mechanism of action remained unknown. We now report that ISRIB is an activator of eIF2B. Our reporter-based shRNA screen revealed an eIF2B requirement for ISRIB activity. Our results define ISRIB as a symmetric molecule, show ISRIB-mediated stabilization of activated eIF2B dimers, and suggest that eIF2B4 (δ-subunit) contributes to the ISRIB binding site. We also developed new ISRIB analogs, improving its EC50 to 600 pM in cell culture. By modulating eIF2B function, ISRIB promises to be an invaluable tool in proof-of-principle studies aiming to ameliorate cognitive defects resulting from neurodegenerative diseases. DOI: http://dx.doi.org/10.7554/eLife.07314.001 PMID:25875391

Improving Enlisted Fleet Manning

DTIC Science & Technology

2014-07-01

instance, if initial training is 9 months long, the first sea tour would be 51 months long under T+X. • “ 4YO /60”: A 4-year initial obligation and a 60...months Increase student IA BA from 236 to 316 CS Sea manning overage overall and at E-5; sea manning gaps at E-8 and E-9 Stay at 4YO /54 Lengthen...from 4YO /60 to 5YO/60 Shorten first shore tour to 26 months Lengthen second shore tour to 48 months Lengthen third sea tour to 48 months Increase

Hypermethylated-capped selenoprotein mRNAs in mammals

PubMed Central

Wurth, Laurence; Gribling-Burrer, Anne-Sophie; Verheggen, Céline; Leichter, Michael; Takeuchi, Akiko; Baudrey, Stéphanie; Martin, Franck; Krol, Alain; Bertrand, Edouard; Allmang, Christine

2014-01-01

Mammalian mRNAs are generated by complex and coordinated biogenesis pathways and acquire 5′-end m7G caps that play fundamental roles in processing and translation. Here we show that several selenoprotein mRNAs are not recognized efficiently by translation initiation factor eIF4E because they bear a hypermethylated cap. This cap modification is acquired via a 5′-end maturation pathway similar to that of the small nucle(ol)ar RNAs (sn- and snoRNAs). Our findings also establish that the trimethylguanosine synthase 1 (Tgs1) interacts with selenoprotein mRNAs for cap hypermethylation and that assembly chaperones and core proteins devoted to sn- and snoRNP maturation contribute to recruiting Tgs1 to selenoprotein mRNPs. We further demonstrate that the hypermethylated-capped selenoprotein mRNAs localize to the cytoplasm, are associated with polysomes and thus translated. Moreover, we found that the activity of Tgs1, but not of eIF4E, is required for the synthesis of the GPx1 selenoprotein in vivo. PMID:25013170

Evaluation of the Initiation/Promotion Potential of CTFE Trimer Acid

DTIC Science & Technology

1990-11-01

0 1 0 0 0 0 0 0 0 Atrophic hepatic cords 3 Cc Cc Cc Cc Cc Cc Cc 3 0e Ce Ce 0e Ge 0e Ce Steatosis 3 2 4 4 4 4 4 3 2 1 0 2 2 1 2 1 Kuppfercell pigment...with the formation of hepatic tumors. Therefore, the present study was designed to evaluate CTFE trimer acid for both tumor initiation and promoting...oxidation of palmitoyl coenzyme A (CoA) MOelRaso, unpublished findings). Many compounds cause an increase in the number of hepatic peroxisomes and are

Minimum-noise production of translation factor eIF4G maps to a mechanistically determined optimal rate control window for protein synthesis

PubMed Central

Meng, Xiang; Firczuk, Helena; Pietroni, Paola; Westbrook, Richard; Dacheux, Estelle; Mendes, Pedro; McCarthy, John E.G.

2017-01-01

Gene expression noise influences organism evolution and fitness. The mechanisms determining the relationship between stochasticity and the functional role of translation machinery components are critical to viability. eIF4G is an essential translation factor that exerts strong control over protein synthesis. We observe an asymmetric, approximately bell-shaped, relationship between the average intracellular abundance of eIF4G and rates of cell population growth and global mRNA translation, with peak rates occurring at normal physiological abundance. This relationship fits a computational model in which eIF4G is at the core of a multi-component–complex assembly pathway. This model also correctly predicts a plateau-like response of translation to super-physiological increases in abundance of the other cap-complex factors, eIF4E and eIF4A. Engineered changes in eIF4G abundance amplify noise, demonstrating that minimum stochasticity coincides with physiological abundance of this factor. Noise is not increased when eIF4E is overproduced. Plasmid-mediated synthesis of eIF4G imposes increased global gene expression stochasticity and reduced viability because the intrinsic noise for this factor influences total cellular gene noise. The naturally evolved eIF4G gene expression noise minimum maps within the optimal activity zone dictated by eIF4G's mechanistic role. Rate control and noise are therefore interdependent and have co-evolved to share an optimal physiological abundance point. PMID:27928055

2,4,6-Trichlorophenol cytotoxicity involves oxidative stress, endoplasmic reticulum stress, and apoptosis.

PubMed

Zhang, Xiaoning; Zhang, Xiaona; Niu, Zhidan; Qi, Yongmei; Huang, Dejun; Zhang, Yingmei

2014-01-01

This study aims to evaluate the cytotoxicity and potential mechanisms of 2,4,6-trichlorophenol (2,4,6-TCP) in mouse embryonic fibroblasts. Our results show that 2,4,6-TCP causes morphological changes and reduces cell viability. The overproduction of reactive oxygen species, the upregulation of nuclear factor-E2-related factor 2 (Nrf2) and heme oxygenase 1 (HMOX1) messenger RNA (mRNA) expressions, and the nuclear translocation of Nrf2 protein demonstrate that 2,4,6-TCP induces oxidative stress, and the Nrf2/HMOX1 pathway might be involved in 2,4,6-TCP-induced antioxidative response. Simultaneously, our data also demonstrate that 2,4,6-TCP upregulates the expressions of binding immunoglobulin protein, inositol-requiring enzyme/endonuclease 1α, and C/EBP homologous protein; stimulates α subunit of eukaryotic translation initiation factor 2 phosphorylation; and induces the splicing of Xbp1 mRNA, suggesting that endoplasmic reticulum (ER) stress is triggered. Moreover, 2,4,6-TCP alters the mitochondrial membrane potential and increases the apoptosis rate, the caspase 3 activity, and the Bax/Bcl-2 ratio, demonstrating that the mitochondrial pathway is involved in the 2,4,6-TCP-induced apoptosis. Thus, these results show that 2,4,6-TCP induces oxidative stress, ER stress, and apoptosis, which together contribute to its cytotoxicity in vitro. © The Author(s) 2014.

Two related trypanosomatid eIF4G homologues have functional differences compatible with distinct roles during translation initiation

PubMed Central

Moura, Danielle MN; Reis, Christian RS; Xavier, Camila C; da Costa Lima, Tamara D; Lima, Rodrigo P; Carrington, Mark; de Melo Neto, Osvaldo P

2015-01-01

In higher eukaryotes, eIF4A, eIF4E and eIF4G homologues interact to enable mRNA recruitment to the ribosome. eIF4G acts as a scaffold for these interactions and also interacts with other proteins of the translational machinery. Trypanosomatid protozoa have multiple homologues of eIF4E and eIF4G and the precise function of each remains unclear. Here, 2 previously described eIF4G homologues, EIF4G3 and EIF4G4, were further investigated. In vitro, both homologues bound EIF4AI, but with different interaction properties. Binding to distinct eIF4Es was also confirmed; EIF4G3 bound EIF4E4 while EIF4G4 bound EIF4E3, both these interactions required similar binding motifs. EIF4G3, but not EIF4G4, interacted with PABP1, a poly-A binding protein homolog. Work in vivo with Trypanosoma brucei showed that both EIF4G3 and EIF4G4 are cytoplasmic and essential for viability. Depletion of EIF4G3 caused a rapid reduction in total translation while EIF4G4 depletion led to changes in morphology but no substantial inhibition of translation. Site-directed mutagenesis was used to disrupt interactions of the eIF4Gs with either eIF4E or eIF4A, causing different levels of growth inhibition. Overall the results show that only EIF4G3, with its cap binding partner EIF4E4, plays a major role in translational initiation. PMID:25826663

Hepatitis C virus core protein targets 4E-BP1 expression and phosphorylation and potentiates Myc-induced liver carcinogenesis in transgenic mice.

PubMed

Abdallah, Cosette; Lejamtel, Charlène; Benzoubir, Nassima; Battaglia, Serena; Sidahmed-Adrar, Nazha; Desterke, Christophe; Lemasson, Matthieu; Rosenberg, Arielle R; Samuel, Didier; Bréchot, Christian; Pflieger, Delphine; Le Naour, François; Bourgeade, Marie-Françoise

2017-08-22

Hepatitis C virus (HCV) is a leading cause of liver diseases including the development of hepatocellular carcinoma (HCC). Particularly, core protein has been involved in HCV-related liver pathologies. However, the impact of HCV core on signaling pathways supporting the genesis of HCC remains largely elusive. To decipher the host cell signaling pathways involved in the oncogenic potential of HCV core, a global quantitative phosphoproteomic approach was carried out. This study shed light on novel differentially phosphorylated proteins, in particular several components involved in translation. Among the eukaryotic initiation factors that govern the translational machinery, 4E-BP1 represents a master regulator of protein synthesis that is associated with the development and progression of cancers due to its ability to increase protein expression of oncogenic pathways. Enhanced levels of 4E-BP1 in non-modified and phosphorylated forms were validated in human hepatoma cells and in mouse primary hepatocytes expressing HCV core, in the livers of HCV core transgenic mice as well as in HCV-infected human primary hepatocytes. The contribution of HCV core in carcinogenesis and the status of 4E-BP1 expression and phosphorylation were studied in HCV core/Myc double transgenic mice. HCV core increased the levels of 4E-BP1 expression and phosphorylation and significantly accelerated the onset of Myc-induced tumorigenesis in these double transgenic mice. These results reveal a novel function of HCV core in liver carcinogenesis potentiation. They position 4E-BP1 as a tumor-specific target of HCV core and support the involvement of the 4E-BP1/eIF4E axis in hepatocarcinogenesis.

Comparative Transcriptome Analysis of Fetal Skin Reveals Key Genes Related to Hair Follicle Morphogenesis in Cashmere Goats.

PubMed

Gao, Ye; Wang, Xiaolong; Yan, Hailong; Zeng, Jie; Ma, Sen; Niu, Yiyuan; Zhou, Guangxian; Jiang, Yu; Chen, Yulin

2016-01-01

Cashmere goat skin contains two types of hair follicles (HF): primary hair follicles (PHF) and secondary hair follicles (SHF). Although multiple genetic determinants associated with HF formation have been identified, the molecules that determine the independent morphogenesis of HF in cashmere goats remain elusive. The growth and development of SHF directly influence the quantity and quality of cashmere production. Here, we report the transcriptome profiling analysis of nine skin samples from cashmere goats using 60- and 120-day-old embryos (E60 and E120, respectively), as well as newborns (NB), through RNA-sequencing (RNA-seq). HF morphological changes indicated that PHF were initiated at E60, with maturation from E120, while differentiation of SHF was identified at E120 until formation of cashmere occurred after birth (NB). The RNA-sequencing analysis generated over 20.6 million clean reads from each mRNA library. The number of differentially expressed genes (DEGs) in E60 vs. E120, E120 vs. NB, and E60 vs. NB were 1,024, 0 and 1,801, respectively, indicating that no significant differences were found at transcriptomic levels between E120 and NB. Key genes including B4GALT4, TNC, a-integrin, and FGFR1, were up-regulated and expressed in HF initiation from E60 to E120, while regulatory genes such as GPRC5D, PAD3, HOXC13, PRR9, VSIG8, LRRC15, LHX2, MSX-2, and FOXN1 were up-regulated and expressed in HF keratinisation and hair shaft differentiation from E120 and NB to E60. Several genes belonging to the KRT and KRTAP gene families were detected throughout the three HF developmental stages. The transcriptional trajectory analyses of all DEGs indicated that immune privilege, glycosaminoglycan biosynthesis, extracellular matrix receptor interaction, and growth factor receptors all played dominant roles in the epithelial-mesenchymal interface and HF formation. We found that the Wnt, transforming growth factor-beta/bone morphogenetic protein, and Notch family members played vital roles in HF differentiation and maturation. The DEGs we found could be attributed to the generation and development of HF, and thus will be critically important for improving the quantity and quality of fleece production in animals for fibres.

The eukaryotic translation initiation factor 3 subunit E binds to classical swine fever virus NS5A and facilitates viral replication.

PubMed

Liu, Xiaofeng; Wang, Xiaoyu; Wang, Qian; Luo, Mingyang; Guo, Huancheng; Gong, Wenjie; Tu, Changchun; Sun, Jinfu

2018-02-01

Classical swine fever virus (CSFV) NS5A protein is a multifunctional protein, playing critical roles in viral RNA replication, translation and assembly. To further explore its functions in viral replication, interaction of NS5A with host factors was assayed using a his-tag "pull down" assay coupled with shotgun LC-MS/MS. Host protein translation initiation factor 3 subunit E was identified as a binding partner of NS5A, and confirmed by co-immunoprecipitation and co-localization analysis. Overexpression of eIF3E markedly enhanced CSFV genomic replication, viral protein expression and production of progeny virus, and downregulation of eIF3E by siRNA significantly decreased viral proliferation in PK-15 cells. Luciferase reporter assay showed an enhancement of translational activity of the internal ribosome entry site of CSFV by eIF3E and a decrease in cellular translation by NS5A. These data indicate that eIF3E plays an important role in CSFV replication, thereby identifying it as a potential target for inhibition of the virus. Copyright © 2017 Elsevier Inc. All rights reserved.

Retrospective study of long-term outcomes of enzyme replacement therapy in Fabry disease: Analysis of prognostic factors

PubMed Central

Biegstraaten, Marieke; Hughes, Derralynn A.; Mehta, Atul; Elliott, Perry M.; Oder, Daniel; Watkinson, Oliver T.; Vaz, Frédéric M.; van Kuilenburg, André B. P.; Wanner, Christoph; Hollak, Carla E. M.

2017-01-01

Despite enzyme replacement therapy, disease progression is observed in patients with Fabry disease. Identification of factors that predict disease progression is needed to refine guidelines on initiation and cessation of enzyme replacement therapy. To study the association of potential biochemical and clinical prognostic factors with the disease course (clinical events, progression of cardiac and renal disease) we retrospectively evaluated 293 treated patients from three international centers of excellence. As expected, age, sex and phenotype were important predictors of event rate. Clinical events before enzyme replacement therapy, cardiac mass and eGFR at baseline predicted an increased event rate. eGFR was the most important predictor: hazard ratios increased from 2 at eGFR <90 ml/min/1.73m2 to 4 at eGFR <30, compared to patients with an eGFR >90. In addition, men with classical disease and a baseline eGFR <60 ml/min/1.73m2 had a faster yearly decline (-2.0 ml/min/1.73m2) than those with a baseline eGFR of >60. Proteinuria was a further independent risk factor for decline in eGFR. Increased cardiac mass at baseline was associated with the most robust decrease in cardiac mass during treatment, while presence of cardiac fibrosis predicted a stronger increase in cardiac mass (3.36 gram/m2/year). Of other cardiovascular risk factors, hypertension significantly predicted the risk for clinical events. In conclusion, besides increasing age, male sex and classical phenotype, faster disease progression while on enzyme replacement therapy is predicted by renal function, proteinuria and to a lesser extent cardiac fibrosis and hypertension. PMID:28763515

Functional Characterization of the Role of the N-terminal Domain of the c/Nip1 Subunit of Eukaryotic Initiation Factor 3 (eIF3) in AUG Recognition*

PubMed Central

Karásková, Martina; Gunišová, Stanislava; Herrmannová, Anna; Wagner, Susan; Munzarová, Vanda; Valášek, Leoš Shivaya

2012-01-01

In eukaryotes, for a protein to be synthesized, the 40 S subunit has to first scan the 5′-UTR of the mRNA until it has encountered the AUG start codon. Several initiation factors that ensure high fidelity of AUG recognition were identified previously, including eIF1A, eIF1, eIF2, and eIF5. In addition, eIF3 was proposed to coordinate their functions in this process as well as to promote their initial binding to 40 S subunits. Here we subjected several previously identified segments of the N-terminal domain (NTD) of the eIF3c/Nip1 subunit, which mediates eIF3 binding to eIF1 and eIF5, to semirandom mutagenesis to investigate the molecular mechanism of eIF3 involvement in these reactions. Three major classes of mutant substitutions or internal deletions were isolated that affect either the assembly of preinitiation complexes (PICs), scanning for AUG, or both. We show that eIF5 binds to the extreme c/Nip1-NTD (residues 1–45) and that impairing this interaction predominantly affects the PIC formation. eIF1 interacts with the region (60–137) that immediately follows, and altering this contact deregulates AUG recognition. Together, our data indicate that binding of eIF1 to the c/Nip1-NTD is equally important for its initial recruitment to PICs and for its proper functioning in selecting the translational start site. PMID:22718758

Region 4 of Rhizobium etli Primary Sigma Factor (SigA) Confers Transcriptional Laxity in Escherichia coli.

PubMed

Santillán, Orlando; Ramírez-Romero, Miguel A; Lozano, Luis; Checa, Alberto; Encarnación, Sergio M; Dávila, Guillermo

2016-01-01

Sigma factors are RNA polymerase subunits engaged in promoter recognition and DNA strand separation during transcription initiation in bacteria. Primary sigma factors are responsible for the expression of housekeeping genes and are essential for survival. RpoD, the primary sigma factor of Escherichia coli, a γ-proteobacteria, recognizes consensus promoter sequences highly similar to those of some α-proteobacteria species. Despite this resemblance, RpoD is unable to sustain transcription from most of the α-proteobacterial promoters tested so far. In contrast, we have found that SigA, the primary sigma factor of Rhizobium etli, an α-proteobacteria, is able to transcribe E. coli promoters, although it exhibits only 48% identity (98% coverage) to RpoD. We have called this the transcriptional laxity phenomenon. Here, we show that SigA partially complements the thermo-sensitive deficiency of RpoD285 from E. coli strain UQ285 and that the SigA region σ4 is responsible for this phenotype. Sixteen out of 74 residues (21.6%) within region σ4 are variable between RpoD and SigA. Mutating these residues significantly improves SigA ability to complement E. coli UQ285. Only six of these residues fall into positions already known to interact with promoter DNA and to comprise a helix-turn-helix motif. The remaining variable positions are located on previously unexplored sites inside region σ4, specifically into the first two α-helices of the region. Neither of the variable positions confined to these helices seem to interact directly with promoter sequence; instead, we adduce that these residues participate allosterically by contributing to correct region folding and/or positioning of the HTH motif. We propose that transcriptional laxity is a mechanism for ensuring transcription in spite of naturally occurring mutations from endogenous promoters and/or horizontally transferred DNA sequences, allowing survival and fast environmental adaptation of α-proteobacteria.

Region 4 of Rhizobium etli Primary Sigma Factor (SigA) Confers Transcriptional Laxity in Escherichia coli

PubMed Central

Santillán, Orlando; Ramírez-Romero, Miguel A.; Lozano, Luis; Checa, Alberto; Encarnación, Sergio M.; Dávila, Guillermo

2016-01-01

Sigma factors are RNA polymerase subunits engaged in promoter recognition and DNA strand separation during transcription initiation in bacteria. Primary sigma factors are responsible for the expression of housekeeping genes and are essential for survival. RpoD, the primary sigma factor of Escherichia coli, a γ-proteobacteria, recognizes consensus promoter sequences highly similar to those of some α-proteobacteria species. Despite this resemblance, RpoD is unable to sustain transcription from most of the α-proteobacterial promoters tested so far. In contrast, we have found that SigA, the primary sigma factor of Rhizobium etli, an α-proteobacteria, is able to transcribe E. coli promoters, although it exhibits only 48% identity (98% coverage) to RpoD. We have called this the transcriptional laxity phenomenon. Here, we show that SigA partially complements the thermo-sensitive deficiency of RpoD285 from E. coli strain UQ285 and that the SigA region σ4 is responsible for this phenotype. Sixteen out of 74 residues (21.6%) within region σ4 are variable between RpoD and SigA. Mutating these residues significantly improves SigA ability to complement E. coli UQ285. Only six of these residues fall into positions already known to interact with promoter DNA and to comprise a helix-turn-helix motif. The remaining variable positions are located on previously unexplored sites inside region σ4, specifically into the first two α-helices of the region. Neither of the variable positions confined to these helices seem to interact directly with promoter sequence; instead, we adduce that these residues participate allosterically by contributing to correct region folding and/or positioning of the HTH motif. We propose that transcriptional laxity is a mechanism for ensuring transcription in spite of naturally occurring mutations from endogenous promoters and/or horizontally transferred DNA sequences, allowing survival and fast environmental adaptation of α-proteobacteria. PMID:27468278

Eukaryotic translation initiation factor 3 plays distinct roles at the mRNA entry and exit channels of the ribosomal preinitiation complex

PubMed Central

Aitken, Colin Echeverría; Beznosková, Petra; Vlčkova, Vladislava; Chiu, Wen-Ling; Zhou, Fujun; Valášek, Leoš Shivaya; Hinnebusch, Alan G; Lorsch, Jon R

2016-01-01

Eukaryotic translation initiation factor 3 (eIF3) is a central player in recruitment of the pre-initiation complex (PIC) to mRNA. We probed the effects on mRNA recruitment of a library of S. cerevisiae eIF3 functional variants spanning its 5 essential subunits using an in vitro-reconstituted system. Mutations throughout eIF3 disrupt its interaction with the PIC and diminish its ability to accelerate recruitment to a native yeast mRNA. Alterations to the eIF3a CTD and eIF3b/i/g significantly slow mRNA recruitment, and mutations within eIF3b/i/g destabilize eIF2•GTP•Met-tRNAi binding to the PIC. Using model mRNAs lacking contacts with the 40S entry or exit channels, we uncovered a critical role for eIF3 requiring the eIF3a NTD, in stabilizing mRNA interactions at the exit channel, and an ancillary role at the entry channel requiring residues of the eIF3a CTD. These functions are redundant: defects at each channel can be rescued by filling the other channel with mRNA. DOI: http://dx.doi.org/10.7554/eLife.20934.001 PMID:27782884

Tobacco and e-cigarette products initiate Kupffer cell inflammatory responses.

PubMed

Rubenstein, David A; Hom, Sarah; Ghebrehiwet, Berhane; Yin, Wei

2015-10-01

Kupffer cells are liver resident macrophages that are responsible for screening and clearing blood of pathogens and foreign particles. It has recently been shown that Kupffer cells interact with platelets, through an adhesion based mechanism, to aid in pathogen clearance and then these platelets re-enter the general systemic circulation. Thus, a mechanism has been identified that relates liver inflammation to possible changes in the systemic circulation. However, the role that Kupffer cells play in cardiovascular disease initiation/progression has not been elucidated. Thus, our objective was to determine whether or not Kupffer cells are responsive to a classical cardiovascular risk factor and if these changes can be transmitted into the general systemic circulation. If Kupffer cells initiate inflammatory responses after exposure to classical cardiovascular risk factors, then this provides a potential alternative/synergistic pathway for cardiovascular disease initiation. We aimed to elucidate the prevalence of this potential pathway. We hypothesized that Kupffer cells would initiate a robust inflammatory response after exposure to tobacco cigarette or e-cigarette products and that the inflammatory response would have the potential to antagonize other salient cells for cardiovascular disease progression. To test this, Kupffer cells were incubated with tobacco smoke extracts, e-cigarette vapor extracts or pure nicotine. Complement deposition onto Kupffer cells, Kupffer cell complement receptor expression, oxidative stress production, cytokine release and viability and density were assessed after the exposure. We observed a robust inflammatory response, oxidative stress production and cytokine release after Kupffer cells were exposed to tobacco or e-cigarette extracts. We also observed a marginal decrease in cell viability coupled with a significant decrease in cell density. In general, this was not a function of the extract formulation (e.g. tobacco vs. e-cigarette products or the formulation of the cigarette product). These results indicate that Kupffer cells are responsive to classical cardiovascular risk factors and that an inflammatory response is initiated that may pass into the general systemic circulation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Geographical gradient of the eIF4E alleles conferring resistance to potyviruses in pea (Pisum) germplasm.

PubMed

Konečná, Eva; Šafářová, Dana; Navrátil, Milan; Hanáček, Pavel; Coyne, Clarice; Flavell, Andrew; Vishnyakova, Margarita; Ambrose, Mike; Redden, Robert; Smýkal, Petr

2014-01-01

The eukaryotic translation initiation factor 4E was shown to be involved in resistance against several potyviruses in plants, including pea. We combined our knowledge of pea germplasm diversity with that of the eIF4E gene to identify novel genetic diversity. Germplasm of 2803 pea accessions was screened for eIF4E intron 3 length polymorphism, resulting in the detection of four eIF4E(A-B-C-S) variants, whose distribution was geographically structured. The eIF4E(A) variant conferring resistance to the P1 PSbMV pathotype was found in 53 accessions (1.9%), of which 15 were landraces from India, Afghanistan, Nepal, and 7 were from Ethiopia. A newly discovered variant, eIF4E(B), was present in 328 accessions (11.7%) from Ethiopia (29%), Afghanistan (23%), India (20%), Israel (25%) and China (39%). The eIF4E(C) variant was detected in 91 accessions (3.2% of total) from India (20%), Afghanistan (33%), the Iberian Peninsula (22%) and the Balkans (9.3%). The eIF4E(S) variant for susceptibility predominated as the wild type. Sequencing of 73 samples, identified 34 alleles at the whole gene, 26 at cDNA and 19 protein variants, respectively. Fifteen alleles were virologically tested and 9 alleles (eIF4E(A-1-2-3-4-5-6-7), eIF4E(B-1), eIF4E(C-2)) conferred resistance to the P1 PSbMV pathotype. This work identified novel eIF4E alleles within geographically structured pea germplasm and indicated their independent evolution from the susceptible eIF4E(S1) allele. Despite high variation present in wild Pisum accessions, none of them possessed resistance alleles, supporting a hypothesis of distinct mode of evolution of resistance in wild as opposed to crop species. The Highlands of Central Asia, the northern regions of the Indian subcontinent, Eastern Africa and China were identified as important centers of pea diversity that correspond with the diversity of the pathogen. The series of alleles identified in this study provides the basis to study the co-evolution of potyviruses and the pea host.

Two highly similar DEAD box proteins, OsRH2 and OsRH34, homologous to eukaryotic initiation factor 4AIII, play roles of the exon junction complex in regulating growth and development in rice.

PubMed

Huang, Chun-Kai; Sie, Yi-Syuan; Chen, Yu-Fu; Huang, Tian-Sheng; Lu, Chung-An

2016-04-12

The exon junction complex (EJC), which contains four core components, eukaryotic initiation factor 4AIII (eIF4AIII), MAGO/NASHI (MAGO), Y14/Tsunagi/RNA-binding protein 8A, and Barentsz/Metastatic lymph node 51, is formed in both nucleus and cytoplasm, and plays important roles in gene expression. Genes encoding core EJC components have been found in plants, including rice. Currently, the functional characterizations of MAGO and Y14 homologs have been demonstrated in rice. However, it is still unknown whether eIF4AIII is essential for the functional EJC in rice. This study investigated two DEAD box RNA helicases, OsRH2 and OsRH34, which are homologous to eIF4AIII, in rice. Amino acid sequence analysis indicated that OsRH2 and OsRH34 had 99 % identity and 100 % similarity, and their gene expression patterns were similar in various rice tissues, but the level of OsRH2 mRNA was about 58-fold higher than that of OsRH34 mRNA in seedlings. From bimolecular fluorescence complementation results, OsRH2 and OsRH34 interacted physically with OsMAGO1 and OsY14b, respectively, which indicated that both of OsRH2 and OsRH34 were core components of the EJC in rice. To study the biological roles of OsRH2 and OsRH34 in rice, transgenic rice plants were generated by RNA interference. The phenotypes of three independent OsRH2 and OsRH34 double-knockdown transgenic lines included dwarfism, a short internode distance, reproductive delay, defective embryonic development, and a low seed setting rate. These phenotypes resembled those of mutants with gibberellin-related developmental defects. In addition, the OsRH2 and OsRH34 double-knockdown transgenic lines exhibited the accumulation of unspliced rice UNDEVELOPED TAPETUM 1 mRNA. Rice contains two eIF4AIII paralogous genes, OsRH2 and OsRH34. The abundance of OsRH2 mRNA was about 58-fold higher than that of OsRH34 mRNA in seedlings, suggesting that the OsRH2 is major eIF4AIII in rice. Both OsRH2 and OsRH34 are core components of the EJC, and participate in regulating of plant height, pollen, and seed development in rice.

Rapid Detection and Isolation of Escherichia coli O104:H4 from Milk Using Monoclonal Antibody-coated Magnetic Beads

PubMed Central

Luciani, Mirella; Di Febo, Tiziana; Zilli, Katiuscia; Di Giannatale, Elisabetta; Armillotta, Gisella; Manna, Laura; Minelli, Fabio; Tittarelli, Manuela; Caprioli, Alfredo

2016-01-01

Monoclonal antibodies (MAbs) specific for the lipopolysaccharide (LPS) of Escherichia coli O104:H4 were produced by fusion of Sp2/O-Ag-14 mouse myeloma cells with spleen cells of Balb/c mice, immunized with heat-inactivated and sonicated E. coli O104:H4 bacterial cells. Four MAbs specific for the E. coli O104:H4 LPS (1E6G6, 1F4C9, 3G6G7, and 4G10D2) were characterized and evaluated for the use in a method for the detection of E. coli O104:H4 in milk samples that involves antibody conjugation to magnetic microbeads to reduce time and increase the efficiency of isolation. MAb 1E6G6 was selected and coupled to microbeads, then used for immuno-magnetic separation (IMS); the efficiency of the IMS method for E. coli O104:H4 isolation from milk was evaluated and compared to that of the EU RL VTEC conventional culture-based isolation procedure. Milk suspensions also containing other pathogenic bacteria that could potentially be found in milk (Campylobacter jejuni, Listeria monocytogenes, and Staphylococcus aureus) were also tested to evaluate the specificity of MAb-coated beads. Beads coated with MAb 1E6G6 showed a good ability to capture the E. coli O104:H4, even in milk samples contaminated with other bacteria, with a higher number of E. coli O104:H4 CFU reisolated in comparison with the official method (121 and 41 CFU, respectively, at 103 E. coli O104:H4 initial load; 19 and 6 CFU, respectively, at 102 E. coli O104:H4 initial load; 1 and 0 CFU, respectively, at 101 E. coli O104:H4 initial load). The specificity was 100%. PMID:27379071

Real-Time Characterization of Virulence Factor Expression in Yersinia pestis Using a Green Fluorescent Protein Reporter System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forde, C; Rocco, J; Fitch, J P

2004-06-09

A real-time reporter system was developed to monitor the thermal induction of virulence factors in Yersinia pestis. The reporter system consists of a plasmid in Y. pestis in which the expression of green fluorescent protein (GFP) is under the control of the promoters for six virulence factors, yopE, sycE, yopK, yopT, yscN, and lcrE/yopN, which are all components of the Type III secretion virulence mechanism of Y. pestis. Induction of the expression of these genes in vivo was determined by the increase in fluorescence intensity of GFP in real time. Basal expression levels observed for the Y. pestis promoters, expressedmore » as percentages of the positive control with GFP under the control of the lac promoter, were: yopE (15%), sycE (15%), yopK (13%), yopT (4%), lcrE (3.3%) and yscN (0.8%). The yopE reporter showed the strongest gene induction following temperature transition from 26 C to 37 C. The induction levels of the other virulence factors, expressed as percentages of yopE induction, were: yopK (57%), sycE (9%), yscN (3%), lcrE (3%), and yopT (2%). The thermal induction of each of these promoter fusions was repressed by calcium, and the ratios of the initial rates of thermal induction without calcium supplementation compared to the rate with calcium supplementation were: yopE (11 fold), yscN (7 fold), yopK (6 fold), lcrE (3 fold), yopT (2 fold), and sycE (2 fold). This work demonstrates a novel approach to quantify gene induction and provides a method to rapidly determine the effects of external stimuli on expression of Y. pestis virulence factors in real time, in living cells.« less

Structural characterization of ribosome recruitment and translocation by type IV IRES

PubMed Central

Murray, Jason; Savva, Christos G; Shin, Byung-Sik; Dever, Thomas E; Ramakrishnan, V; Fernández, Israel S

2016-01-01

Viral mRNA sequences with a type IV IRES are able to initiate translation without any host initiation factors. Initial recruitment of the small ribosomal subunit as well as two translocation steps before the first peptidyl transfer are essential for the initiation of translation by these mRNAs. Using electron cryomicroscopy (cryo-EM) we have structurally characterized at high resolution how the Cricket Paralysis Virus Internal Ribosomal Entry Site (CrPV-IRES) binds the small ribosomal subunit (40S) and the translocation intermediate stabilized by elongation factor 2 (eEF2). The CrPV-IRES restricts the otherwise flexible 40S head to a conformation compatible with binding the large ribosomal subunit (60S). Once the 60S is recruited, the binary CrPV-IRES/80S complex oscillates between canonical and rotated states (Fernández et al., 2014; Koh et al., 2014), as seen for pre-translocation complexes with tRNAs. Elongation factor eEF2 with a GTP analog stabilizes the ribosome-IRES complex in a rotated state with an extra ~3 degrees of rotation. Key residues in domain IV of eEF2 interact with pseudoknot I (PKI) of the CrPV-IRES stabilizing it in a conformation reminiscent of a hybrid tRNA state. The structure explains how diphthamide, a eukaryotic and archaeal specific post-translational modification of a histidine residue of eEF2, is involved in translocation. DOI: http://dx.doi.org/10.7554/eLife.13567.001 PMID:27159451

19 CFR 351.218 - Sunset reviews under section 751(c) of the Act.

Code of Federal Regulations, 2010 CFR

2010-04-01

.... 351.218 Section 351.218 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE... the Act and § 351.203(e)(4), the Secretary may decline the request for early initiation. (4... (E) The citation and date of publication in the Federal Register of the notice of initiation. (iii...

Training and retaining staff to competently deliver an evidence-based practice: the role of staff attributes and perceptions of organizational functioning.

PubMed

Garner, Bryan R; Hunter, Brooke D; Godley, Susan H; Godley, Mark D

2012-03-01

Within the context of an initiative to implement evidence-based practices (EBPs) for adolescents with substance use disorders, this study examined the extent to which staff factors measured at an initial EBP training workshop were predictive of EBP competence and turnover status of staff (N = 121) measured 6, 9, and 12 months posttraining. By the final assessment point, 52.3% of staff transitioned to the employed/EBP-competent category, 26.6% transitioned to the not employed/not EBP-competent category, 4.6% transitioned to the not employed/EBP-competent category, and 16.5% had not transitioned out of the initial category. Multilevel multinomial regression analysis identified several measures that were significant predictors of staff transitions to the not employed/not EBP-competent category (e.g., program needs, job satisfaction, burnout) and transitions to the employed/EBP-competent category (e.g., months in position, pressures for change, influence). Findings have implications for the development and testing of strategies to train and retain staff to deliver EBPs in practice settings. Copyright © 2012 Elsevier Inc. All rights reserved.

Elevated levels of p-Mnk1, p-eIF4E and p-p70S6K proteins are associated with tumor recurrence and poor prognosis in astrocytomas.

PubMed

Fan, Weibing; Wang, Weiyuan; Mao, Xinfa; Chu, Shuzhou; Feng, Juan; Xiao, Desheng; Zhou, Jianhua; Fan, Songqing

2017-02-01

Malignant astrocytomas are able to invade neighboring and distant areas of the normal brain. Signaling pathway alterations play important role in the development of astrocytomas. Deregulation of eukaryotic translation initiation factor 4E (eIF4E) by MAP kinase-interacting kinases (Mnk) on Ser-209 directly or PI3K/mTOR/S6K pathway indirectly has a critical effect on promoting cellular proliferation, malignant transformation and metastasis. We examined and analyzed the correlation between expression of p-Mnk1, p-eIF4E and p-p70S6K proteins and clinicopathological features in 103 astrocytomas and 54 non-tumorous brain tissues. The results indicated that positive percentage of overexpression of p-Mnk1 and p-eIF4E proteins in astrocytomas were significantly higher than that of in the non-tumorous brain tissues (P < 0.05). Elevated p-Mnk1 and p-eIF4E and co-overexpressed three proteins were associated with tumor recurrence (P = 0.003, P = 0.006, P = 0.007, respectively). Overexpressed p-eIF4E significantly correlated with the tumor size (P = 0.019). In addition, overexpression of p-eIF4E and three proteins common expression were related to the WHO grade of astrocytomas (P = 0.001, P = 0.044 respectively). Spearman's rank correlation test further showed that the expression of p-Mnk1 was strongly positive correlated with the expression of p-eIF4E in astrocytomas (r = 0.294, P = 0.003). Besides, overexpression of p-eIF4E and co-expression of p-Mnk1, p-eIF4E and p-p70S6K proteins were inversely correlated with overall survival rates of astrocytomas. Multivariate Cox regression analysis further identified that the elevated p-eIF4E expression, three proteins common expression were correlated with unfavorable prognosis of astrocytomas regardless of ages and WHO grades. Taken together, overexpression of p-eIF4E and co-expression of p-Mnk1, p-eIF4E and p-p70S6K proteins could be used as novel independent poor prognostic biomarkers for patients with astrocytomas.

Transportation Workload Forecasting (TWF) Study.

DTIC Science & Technology

1984-01-01

inflation factors, changes in troop strengths; opening , closing, or consolidation of facilities; and changes in mode of transportation. (4) The Military...tons Initial attempts to read the data with a univariate statistics program failed, due to the existence of nonnumeric entries in data fields . Records...W M=wn.99,i.i.Pm.i-,9Nd.~ C;f* ne hJN lfr csN ewc S.-,n melt rlfMOMf7 . £9 V oocacooofll.O N trtoati9e ieonhnfbo£0 * **. .~ ~~~ ~~~~ n

Prognostic factors for perceived recovery or functional improvement in non-specific low back pain: secondary analyses of three randomized clinical trials

PubMed Central

Staal, J. Bart; Heymans, Martijn W.; Harts, Chris C.; Hendriks, Erik J. M.; de Bie, Rob A.

2009-01-01

The objective of this study was to report on secondary analyses of a merged trial dataset aimed at exploring the potential importance of patient factors associated with clinically relevant improvements in non-acute, non-specific low back pain (LBP). From 273 predominantly male army workers (mean age 39 ± 10.5 years, range 20–56 years, 4 women) with LBP who were recruited in three randomized clinical trials, baseline individual patient factors, pain-related factors, work-related psychosocial factors, and psychological factors were evaluated as potential prognostic variables in a short-term (post-treatment) and a long-term logistic regression model (6 months after treatment). We found one dominant prognostic factor for improvement directly after treatment as well as 6 months later: baseline functional disability, expressed in Roland–Morris Disability Questionnaire scores. Baseline fear of movement, expressed in Tampa Scale for Kinesiophobia scores, had also significant prognostic value for long-term improvement. Less strongly associated with the outcome, but also included in our final models, were supervisor social support and duration of complaints (short-term model), and co-worker social support and pain radiation (long-term model). Information about initial levels of functional disability and fear-avoidance behaviour can be of value in the treatment of patient populations with characteristics comparable to the current army study population (e.g., predominantly male, physically active, working, moderate but chronic back problems). Individuals at risk for poor long-term LBP recovery, i.e., individuals with high initial level of disability and prominent fear-avoidance behaviour, can be distinguished that may need additional cognitive-behavioural treatment. PMID:20035358

Guanabenz promotes neuronal survival via enhancement of ATF4 and parkin expression in models of Parkinson disease.

PubMed

Sun, Xiaotian; Aimé, Pascaline; Dai, David; Ramalingam, Nagendran; Crary, John F; Burke, Robert E; Greene, Lloyd A; Levy, Oren A

2018-05-01

Reduced function of parkin appears to be a central pathogenic event in Parkinson disease (PD). Increasing parkin levels enhances survival in models of PD-related neuronal death and is a promising therapeutic objective. Previously, we demonstrated that the transcription factor ATF4 promotes survival in response to PD-mimetic stressors by maintaining parkin levels. ATF4 translation is up-regulated by phosphorylation of the translation initiation factor eIF2α. The small molecule guanabenz enhances eIF2α phosphorylation by blocking the function of GADD34, a regulatory protein that promotes eIF2α dephosphorylation. We tested the hypothesis that guanabenz, by inhibiting GADD34 and consequently increasing eIF2α phosphorylation and elevating ATF4, would improve survival in models of PD by up-regulating parkin. We found that GADD34 is strongly induced by 6-OHDA, and that GADD34 localization is dramatically altered in dopaminergic substantia nigra neurons in PD cases. We further demonstrated that guanabenz attenuates 6-hydroxydopamine (6-OHDA) induced cell death of differentiated PC12 cells and primary ventral midbrain dopaminergic neurons in culture, and of dopaminergic neurons in the substantia nigra of mice. In culture models, guanabenz also increases eIF2α phosphorylation and ATF4 and parkin levels in response to 6-OHDA. Furthermore, if either ATF4 or parkin is silenced, then the protective effect of guanabenz is lost. We also found similar results in a distinct model of neuronal death: primary cultures of cortical neurons treated with the topoisomerase I inhibitor camptothecin, in which guanabenz limited camptothecin-induced neuronal death in an ATF4- and parkin-dependent manner. In summary, our data suggest that guanabenz and other GADD34 inhibitors could be used as therapeutic agents to boost parkin levels and thereby slow neurodegeneration in PD and other neurodegenerative conditions. Copyright © 2018 Elsevier Inc. All rights reserved.

The DEAD-box helicase eIF4A: paradigm or the odd one out?

PubMed

Andreou, Alexandra Z; Klostermeier, Dagmar

2013-01-01

DEAD-box helicases catalyze the ATP-dependent unwinding of RNA duplexes. They share a helicase core formed by two RecA-like domains that carries a set of conserved motifs contributing to ATP binding and hydrolysis, RNA binding and duplex unwinding. The translation initiation factor eIF4A is the founding member of the DEAD-box protein family, and one of the few examples of DEAD-box proteins that consist of a helicase core only. It is an RNA-stimulated ATPase and a non-processive helicase that unwinds short RNA duplexes. In the catalytic cycle, a series of conformational changes couples the nucleotide cycle to RNA unwinding. eIF4A has been considered a paradigm for DEAD-box proteins, and studies of its function have revealed the governing principles underlying the DEAD-box helicase mechanism. However, as an isolated helicase core, eIF4A is rather the exception, not the rule. Most helicase modules in other DEAD-box proteins are modified, some by insertions into the RecA-like domains, and the majority by N- and C-terminal appendages. While the basic catalytic function resides within the helicase core, its modulation by insertions, additional domains or a network of interaction partners generates the diversity of DEAD-box protein functions in the cell. This review summarizes the current knowledge on eIF4A and its regulation, and discusses to what extent eIF4A serves as a model DEAD-box protein.

The σ70 region 1.2 regulates promoter escape by unwinding DNA downstream of the transcription start site

PubMed Central

Bochkareva, Aleksandra; Zenkin, Nikolay

2013-01-01

The mechanisms of abortive synthesis and promoter escape during initiation of transcription are poorly understood. Here, we show that, after initiation of RNA synthesis, non-specific interaction of σ70 region 1.2, present in all σ70 family factors, with the non-template strand around position −4 relative to the transcription start site facilitates unwinding of the DNA duplex downstream of the transcription start site. This leads to stabilization of short RNA products and allows their extension, i.e. promoter escape. We show that this activity of σ70 region 1.2 is assisted by the β-lobe domain, but does not involve the β′-rudder or the β′-switch-2, earlier proposed to participate in promoter escape. DNA sequence independence of this function of σ70 region 1.2 suggests that it may be conserved in all σ70 family factors. Our results indicate that the abortive nature of initial synthesis is caused, at least in part, by failure to open the downstream DNA by the β-lobe and σ region 1.2. PMID:23430153

Structures of transcription pre-initiation complex with TFIIH and Mediator.

PubMed

Schilbach, S; Hantsche, M; Tegunov, D; Dienemann, C; Wigge, C; Urlaub, H; Cramer, P

2017-11-09

For the initiation of transcription, RNA polymerase II (Pol II) assembles with general transcription factors on promoter DNA to form the pre-initiation complex (PIC). Here we report cryo-electron microscopy structures of the Saccharomyces cerevisiae PIC and PIC-core Mediator complex at nominal resolutions of 4.7 Å and 5.8 Å, respectively. The structures reveal transcription factor IIH (TFIIH), and suggest how the core and kinase TFIIH modules function in the opening of promoter DNA and the phosphorylation of Pol II, respectively. The TFIIH core subunit Ssl2 (a homologue of human XPB) is positioned on downstream DNA by the 'E-bridge' helix in TFIIE, consistent with TFIIE-stimulated DNA opening. The TFIIH kinase module subunit Tfb3 (MAT1 in human) anchors the kinase Kin28 (CDK7), which is mobile in the PIC but preferentially located between the Mediator hook and shoulder in the PIC-core Mediator complex. Open spaces between the Mediator head and middle modules may allow access of the kinase to its substrate, the C-terminal domain of Pol II.

Lambda-cyhalothrin disrupts the up-regulation effect of 17β-estradiol on post-synaptic density 95 protein expression via estrogen receptor α-dependent Akt pathway.

PubMed

Wang, Qunan; Xia, Xin; Deng, Xiaomei; Li, Nian; Wu, Daji; Zhang, Long; Yang, Chengwei; Tao, Fangbiao; Zhou, Jiangning

2016-03-01

Lambda-cyhalothrin (LCT), one of the type II pyrethroids, has been widely used throughout the world. The estrogenic effect of LCT to increase cell proliferation has been well established. However, whether the estrogenic effect of LCT will influence neurodevelopment has not been investigated. In addition, 17β-Estradiol (E2) plays a crucial role in neurodevelopment and induces an increase in synaptic proteins. The post-synaptic density 95 (PSD95) protein, which is involved in the development of the structure and function of new spines and localized with estrogen receptor α (ERα) at the post-synaptic density (PSD), was detected in our study by using hippocampal neuron cell line HT22. We found that LCT up-regulated PSD95 and ERα expression, estrogen receptor (ER) antagonist ICI182,780 and phosphatidylinositol-4; 5-bisphosphate 3-kinase (PI3K) inhibitor LY294,002 blocked this effect. In addition, LCT disrupted the promotion effect of E2 on PSD95. To investigate whether the observed changes are caused by ERα-dependent signaling activation, we next detected the effects of LCT on the ERα-mediated PI3K-Protein kinase B (PKB/Akt)-eukaryotic initiation factor (eIF) 4E-binding protein 1 (4E-BP1) pathway. There existed an activation of Akt and the downstream factor 4E-BP1 after LCT treatment. In addition, LCT could disrupt the activation effect of E2 on the Akt pathway. However, no changes in cAMP response element-binding protein (CREB) activation and PSD95 messenger ribonucleic acid (mRNA) were observed. Our findings demonstrated that LCT could increase the PSD95 protein level via the ERα-dependent Akt pathway, and LCT might disrupt the up-regulation effect of E2 on PSD95 protein expression via this signaling pathway. Copyright © 2015. Published by Elsevier B.V.

Identification of promoter motifs regulating ZmeIF4E expression level involved in maize rough dwarf disease resistance in maize (Zea Mays L.).

PubMed

Shi, Liyu; Weng, Jianfeng; Liu, Changlin; Song, Xinyuan; Miao, Hongqin; Hao, Zhuanfang; Xie, Chuanxiao; Li, Mingshun; Zhang, Degui; Bai, Li; Pan, Guangtang; Li, Xinhai; Zhang, Shihuang

2013-04-01

Maize rough dwarf disease (MRDD, a viral disease) results in significant grain yield losses, while genetic basis of which is largely unknown. Based on comparative genomics, eukaryotic translation initiation factor 4E (eIF4E) was considered as a candidate gene for MRDD resistance, validation of which will help to understand the possible genetic mechanism of this disease. ZmeIF4E (orthologs of eIF4E gene in maize) encodes a protein of 218 amino acids, harboring five exons and no variation in the cDNA sequence is identified between the resistant inbred line, X178 and susceptible one, Ye478. ZmeIF4E expression was different in the two lines plants treated with three plant hormones, ethylene, salicylic acid, and jasmonates at V3 developmental stage, suggesting that ZmeIF4E is more likely to be involved in the regulation of defense gene expression and induction of local and systemic resistance. Moreover, four cis-acting elements related to plant defense responses, including DOFCOREZM, EECCRCAH1, GT1GAMSCAM4, and GT1CONSENSUS were detected in ZmeIF4E promoter for harboring sequence variation in the two lines. Association analysis with 163 inbred lines revealed that one SNP in EECCRCAH1 is significantly associated with CSI of MRDD in two environments, which explained 3.33 and 9.04 % of phenotypic variation, respectively. Meanwhile, one SNP in GT-1 motif was found to affect MRDD resistance only in one of the two environments, which explained 5.17 % of phenotypic variation. Collectively, regulatory motifs respectively harboring the two significant SNPs in ZmeIF4E promoter could be involved in the defense process of maize after viral infection. These results contribute to understand maize defense mechanisms against maize rough dwarf virus.

Phosphorylated 4E binding protein 1: a hallmark of cell signaling that correlates with survival in ovarian cancer.

PubMed

Castellvi, Josep; Garcia, Angel; Rojo, Federico; Ruiz-Marcellan, Carmen; Gil, Antonio; Baselga, Jose; Ramon y Cajal, Santiago

2006-10-15

Growth factor receptors and cell signaling factors play a crucial role in human carcinomas and have been studied in ovarian tumors with varying results. Cell signaling involves multiple pathways and a myriad of factors that can be mutated or amplified. Cell signaling is driven through the mammalian target of rapamycin (mTOR) and extracellular regulated kinase (ERK) pathways and by some downstream molecules, such as 4E binding protein 1 (4EBP1), eukaryotic initiation factor 4E, and p70 ribosomal protein S6 kinase (p70S6K). The objectives of this study were to analyze the real role that these pathways play in ovarian cancer, to correlate them with clinicopathologic characteristics, and to identify the factors that transmit individual proliferation signals and are associated with pathologic grade and prognosis, regardless specific oncogenic alterations upstream. One hundred twenty-nine ovarian epithelial tumors were studied, including 20 serous cystadenomas, 7 mucinous cystadenomas, 11 serous borderline tumors, 16 mucinous borderline tumors, 29 serous carcinomas, 16 endometrioid carcinomas, 15 clear cell carcinomas, and 15 mucinous carcinomas. Tissue microarrays were constructed, and immunohistochemistry for the receptors epidermal growth factor receptor (EGFR) and c-erb-B2 was performed and with phosphorylated antibodies for protein kinase B (AKT), 4EBP1, p70S6K, S6, and ERK. Among 129 ovarian neoplasms, 17.8% were positive for c-erb-B2, 9.3% were positive for EGFR, 47.3% were positive for phosphorylated AKT (p-AKT), 58.9% were positive for p-ERK, 41.1% were positive for p-4EBP1, 26.4% were positive for p70S6K, and 15.5% were positive for p-S6. Although EGFR, p-AKT, and p-ERK expression did not differ between benign, borderline, or malignant tumors, c-erb-B2, p-4EBP1, p-p70S6K, and p-S6 were expressed significantly more often in malignant tumors. Only p-4EBP1 expression demonstrated prognostic significance (P = .005), and only surgical stage and p-4EBP1 expression had statistical significance in the multivariate analysis. In patients with ovarian carcinoma, significant expression of p-4EBP1 was associated with high-grade tumors and a poor prognosis, regardless other oncogenic alterations upstream. This finding supports the study of this factor as a hallmark or pivotal factor in cell signaling in ovarian carcinoma that may crucial in the transmission of the proliferation cell signal and may reflect the real oncogenic role of this pathway in ovarian tumors. 2006 American Cancer Society

Structural characterization of ribosome recruitment and translocation by type IV IRES.

PubMed

Murray, Jason; Savva, Christos G; Shin, Byung-Sik; Dever, Thomas E; Ramakrishnan, V; Fernández, Israel S

2016-05-09

Viral mRNA sequences with a type IV IRES are able to initiate translation without any host initiation factors. Initial recruitment of the small ribosomal subunit as well as two translocation steps before the first peptidyl transfer are essential for the initiation of translation by these mRNAs. Using electron cryomicroscopy (cryo-EM) we have structurally characterized at high resolution how the Cricket Paralysis Virus Internal Ribosomal Entry Site (CrPV-IRES) binds the small ribosomal subunit (40S) and the translocation intermediate stabilized by elongation factor 2 (eEF2). The CrPV-IRES restricts tvhe otherwise flexible 40S head to a conformation compatible with binding the large ribosomal subunit (60S). Once the 60S is recruited, the binary CrPV-IRES/80S complex oscillates between canonical and rotated states (Fernández et al., 2014; Koh et al., 2014), as seen for pre-translocation complexes with tRNAs. Elongation factor eEF2 with a GTP analog stabilizes the ribosome-IRES complex in a rotated state with an extra ~3 degrees of rotation. Key residues in domain IV of eEF2 interact with pseudoknot I (PKI) of the CrPV-IRES stabilizing it in a conformation reminiscent of a hybrid tRNA state. The structure explains how diphthamide, a eukaryotic and archaeal specific post-translational modification of a histidine residue of eEF2, is involved in translocation.

Exploring APOE genotype effects on Alzheimer's disease risk and amyloid β burden in individuals with subjective cognitive decline: The FundacioACE Healthy Brain Initiative (FACEHBI) study baseline results.

PubMed

Moreno-Grau, Sonia; Rodríguez-Gómez, Octavio; Sanabria, Ángela; Pérez-Cordón, Alba; Sánchez-Ruiz, Domingo; Abdelnour, Carla; Valero, Sergi; Hernández, Isabel; Rosende-Roca, Maitée; Mauleón, Ana; Vargas, Liliana; Lafuente, Asunción; Gil, Silvia; Santos-Santos, Miguel Ángel; Alegret, Montserrat; Espinosa, Ana; Ortega, Gemma; Guitart, Marina; Gailhajanet, Anna; de Rojas, Itziar; Sotolongo-Grau, Óscar; Ruiz, Susana; Aguilera, Nuria; Papasey, Judith; Martín, Elvira; Peleja, Esther; Lomeña, Francisco; Campos, Francisco; Vivas, Assumpta; Gómez-Chiari, Marta; Tejero, Miguel Ángel; Giménez, Joan; Serrano-Ríos, Manuel; Orellana, Adelina; Tárraga, Lluís; Ruiz, Agustín; Boada, Mercè

2018-05-01

Subjective cognitive decline (SCD) has been proposed as a potential preclinical stage of Alzheimer's disease (AD). Nevertheless, the genetic and biomarker profiles of SCD individuals remain mostly unexplored. We evaluated apolipoprotein E (APOE) ε4's effect in the risk of presenting SCD, using the Fundacio ACE Healthy Brain Initiative (FACEHBI) SCD cohort and Spanish controls, and performed a meta-analysis addressing the same question. We assessed the relationship between APOE dosage and brain amyloid burden in the FACEHBI SCD and Alzheimer's Disease Neuroimaging Initiative cohorts. Analysis of the FACEHBI cohort and the meta-analysis demonstrated SCD individuals presented higher allelic frequencies of APOE ε4 with respect to controls. APOE dosage explained 9% (FACEHBI cohort) and 11% (FACEHBI and Alzheimer's Disease Neuroimaging Initiative cohorts) of the variance of cerebral amyloid levels. The FACEHBI sample presents APOE ε4 enrichment, suggesting that a pool of AD patients is nested in our sample. Cerebral amyloid levels are partially explained by the APOE allele dosage, suggesting that other genetic or epigenetic factors are involved in this AD endophenotype. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

The retinamide VNLG-152 inhibits f-AR/AR-V7 and MNK-eIF4E signaling pathways to suppress EMT and castration-resistant prostate cancer xenograft growth.

PubMed

Ramamurthy, Vidya P; Ramalingam, Senthilmurugan; Gediya, Lalji K; Njar, Vincent C O

2018-03-01

VNLG-152 is a novel retinamide (NR) shown to suppress growth and progression of genetically diverse prostate cancer cells via inhibition of androgen receptor signaling and eukaryotic initiation factor 4E (eIF4E) translational machinery. Herein, we report therapeutic effects of VNLG-152 on castration-resistant prostate cancer (CRPC) growth and metastatic phenotype in a CRPC tumor xenograft model. Administration of VNLG-152 significantly and dose-dependently suppressed the growth of aggressive CWR22Rv1 tumors by 63.4% and 76.3% at 10 and 20 mg·kg -1 bw, respectively (P < 0.0001), vs. vehicle with no host toxicity. Strikingly, the expression of full-length androgen receptor (f-AR)/androgen receptor splice variant-7 (AR-V7), mitogen-activated protein kinase-interacting kinases 1 and 2 (MNK1/2), phosphorylated eIF4E and their associated target proteins, including prostate-specific antigen, cyclin D1 and Bcl-2, were strongly decreased in VNLG-152-treated tumors signifying inhibition of f-AR/AR-V7 and MNK-eIF4E signaling in VNLG-152-treated CWR22Rv1 tumors as observed in vitro. VNLG-152 also suppressed the epithelial to mesenchymal transition in CWR22Rv1 tumors as evidenced by repression of N-cadherin, β-catenin, claudin, Slug, Snail, Twist, vimentin and matrix metalloproteinases (MMP-2 and MMP-9) with upsurge in E-cadherin. These results highlight the promising use of VNLG-152 in CRPC therapy and justify its further development towards clinical trials. © 2018 Federation of European Biochemical Societies.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fury, Matthew G.; Department of Medicine, Weill Cornell Medical College, New York, New York; Lee, Nancy Y.

Purpose: Elevated expression of eukaryotic protein synthesis initiation factor 4E (eIF4E) in histologically cancer-free margins of resected head and neck squamous cell carcinomas (HNSCCs) is mediated by mammalian target of rapamycin complex 1 (mTORC1) and has been associated with increased risk of disease recurrence. Preclinically, inhibition of mTORC1 with everolimus sensitizes cancer cells to cisplatin and radiation. Methods and Materials: This was single-institution phase 1 study to establish the maximum tolerated dose of daily everolimus given with fixed dose cisplatin (30 mg/m{sup 2} weekly × 6) and concurrent intensity modulated radiation therapy for patients with locally and/or regionally advanced head-and-neckmore » cancer. The study had a standard 3 + 3 dose-escalation design. Results: Tumor primary sites were oral cavity (4), salivary gland (4), oropharynx (2), nasopharynx (1), scalp (1), and neck node with occult primary (1). In 4 of 4 cases in which resected HNSCC surgical pathology specimens were available for immunohistochemistry, elevated expression of eIF4E was observed in the cancer-free margins. The most common grade ≥3 treatment-related adverse event was lymphopenia (92%), and dose-limiting toxicities (DLTs) were mucositis (n=2) and failure to thrive (n=1). With a median follow up of 19.4 months, 2 patients have experienced recurrent disease. The maximum tolerated dose was everolimus 5 mg/day. Conclusions: Head-and-neck cancer patients tolerated everolimus at therapeutic doses (5 mg/day) given with weekly cisplatin and intensity modulated radiation therapy. The regimen merits further evaluation, especially among patients who are status post resection of HNSCCs that harbor mTORC1-mediated activation of eIF4E in histologically negative surgical margins.« less

What Drives a Successful E-Learning? An Empirical Investigation of the Critical Factors Influencing Learner Satisfaction

ERIC Educational Resources Information Center

Sun, Pei-Chen; Tsai, Ray J.; Finger, Glenn; Chen, Yueh-Yang; Yeh, Dowming

2008-01-01

E-Learning is emerging as the new paradigm of modern education. Worldwide, the e-Learning market has a growth rate of 35.6%, but failures exist. Little is known about why many users stop their online learning after their initial experience. Previous research done under different task environments has suggested a variety of factors affecting user…

Phosphorylation of eIF2α via the general control kinase, GCN2, modulates the ability of renal medullary cells to survive high urea stress

PubMed Central

Cai, Qi

2011-01-01

The phosphorylation of the α-subunit of the eukaryotic translation initiation factor 2 (eIF2α) occurs under many stress conditions in mammalian cells and is mediated by one of four eIF2α kinases: PERK, PKR, GCN2, and HRI. Cells of the renal medulla are regularly exposed to fluctuating concentrations of urea and sodium, the extracellular solutes responsible for the high osmolality in the renal medulla, and thus the kidneys ability to concentrate the urine in times of dehydration. Urea stress is known to initiate molecular responses that diverge from those seen in response to hypertonic stress (NaCl). We show that urea-inducible GCN2 activation initiates the phosphorylation of eIF2α and the downstream increase of activating transcription factor 3 (ATF3). Loss of GCN2 sensitized cells to urea stress, increasing the expression of activated caspase-3 and decreasing cell survival. Loss of GCN2 ablated urea-induced phosphorylation of eIF2α and reduced the expression of ATF3. PMID:21880833

Renal outcomes of agalsidase beta treatment for Fabry disease: role of proteinuria and timing of treatment initiation.

PubMed

Warnock, David G; Ortiz, Alberto; Mauer, Michael; Linthorst, Gabor E; Oliveira, João P; Serra, Andreas L; Maródi, László; Mignani, Renzo; Vujkovac, Bojan; Beitner-Johnson, Dana; Lemay, Roberta; Cole, J Alexander; Svarstad, Einar; Waldek, Stephen; Germain, Dominique P; Wanner, Christoph

2012-03-01

The purpose of this study was to identify determinants of renal disease progression in adults with Fabry disease during treatment with agalsidase beta. Renal function was evaluated in 151 men and 62 women from the Fabry Registry who received agalsidase beta at an average dose of 1 mg/kg/2 weeks for at least 2 years. Patients were categorized into quartiles based on slopes of estimated glomerular filtration rate (eGFR) during treatment. Multivariate logistic regression analyses were used to identify factors associated with renal disease progression. Men within the first quartile had a mean eGFR slope of -0.1 mL/min/1.73m(2)/year, whereas men with the most rapid renal disease progression (Quartile 4) had a mean eGFR slope of -6.7 mL/min/1.73m(2)/year. The risk factor most strongly associated with renal disease progression was averaged urinary protein:creatinine ratio (UP/Cr) ≥1 g/g (odds ratio 112, 95% confidence interval (95% CI) 4-3109, P = 0.0054). Longer time from symptom onset to treatment was also associated with renal disease progression (odds ratio 19, 95% CI 2-184, P = 0.0098). Women in Quartile 4 had the highest averaged UP/Cr (mean 1.8 g/g) and the most rapid renal disease progression: (mean slope -4.4 mL/min/1.73m(2)/year). Adults with Fabry disease are at risk for progressive loss of eGFR despite enzyme replacement therapy, particularly if proteinuria is ≥1 g/g. Men with little urinary protein excretion and those who began receiving agalsidase beta sooner after the onset of symptoms had stable renal function. These findings suggest that early intervention may lead to optimal renal outcomes.

Inhibition of endoplasmic reticulum stress by intermedin1-53 attenuates angiotensin II-induced abdominal aortic aneurysm in ApoE KO Mice.

PubMed

Ni, Xian-Qiang; Lu, Wei-Wei; Zhang, Jin-Sheng; Zhu, Qing; Ren, Jin-Ling; Yu, Yan-Rong; Liu, Xiu-Ying; Wang, Xiu-Jie; Han, Mei; Jing, Qing; Du, Jie; Tang, Chao-Shu; Qi, Yong-Fen

2018-06-26

Endoplasmic reticulum stress (ERS) is involved in the development of abdominal aortic aneurysm (AAA). Since bioactive peptide intermedin (IMD)1-53 protects against AAA formation, here we investigated whether IMD1-53 attenuates AAA by inhibiting ERS. AAA model was induced by angiotensin II (AngII) in ApoE KO mouse background. AngII-treated mouse aortas showed increased ERS gene transcription of caspase12, eukaryotic translation initiation factor 2a (eIf2a) and activating transcription factor 4(ATF4).The protein level of ERS marker glucose regulated protein 94(GRP94), ATF4 and C/EBP homologous protein 10(CHOP) was also up-regulated by AngII. Increased ERS levels were accompanied by severe VSMC apoptosis in human AAA aorta. In vivo administration of IMD1-53 greatly reduced AngII-induced AAA and abrogated the activation of ERS. To determine whether IMD inhibited AAA by ameliorating ERS, we used 2 non-selective ERS inhibitors phenyl butyrate (4-PBA) and taurine (TAU). Similar to IMD, PBA, and TAU significantly reduced the incidence of AAA and AAA-related pathological disorders. In vitro, AngII infusion up-regulated CHOP, caspase12 expression and led to VSMC apoptosis. IMD siRNA aggravated the CHOP, caspase12-mediated VSMC apoptosis, which was abolished by ATF4 silencing. IMD infusion promoted the phosphorylation of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) in aortas in ApoE KO mice, and the AMPK inhibitor compound C abolished the protective effect of IMD on VSMC ERS and apoptosis induced by AngII. In conclusion, IMD may protect against AAA formation by inhibiting ERS via activating AMPK phosphorylation.

Sevoflurane-Induced Endoplasmic Reticulum Stress Contributes to Neuroapoptosis and BACE-1 Expression in the Developing Brain: The Role of eIF2α.

PubMed

Liu, Bin; Xia, Junming; Chen, Yali; Zhang, Jun

2017-02-01

Neonatal exposure to volatile anesthetics causes apoptotic neurodegeneration in the developing brain, possibly leading to neurocognitive deficits in adulthood. Endoplasmic reticulum (ER) stress might be associated with sevoflurane (sevo)-induced neuroapoptosis. However, the signaling pathway regulating sevo-induced neuroapoptosis is not understood. We investigated the effects of neonatal sevo exposure on ER signaling pathway activation. Seven-day-old mouse pups were divided into control (C) and sevo (S; 3 % sevo exposure, 6 h) groups. ER stress marker [protein kinase RNA-like ER kinase (PERK), eukaryotic translation initiation factor 2α (eIF2α), activating transcription factor 4 (ATF4), CHOP, and caspase-12] levels were determined by western blotting. To understand the role of eIF2α in sevo-induced ER stress and caspase-3 activation, pups were pretreated with an eIF2α dephosphorylation inhibitor, salubrinal, and a potent and selective inhibitor of PERK, GSK2656157, before sevo exposure, and the effects on ER stress signaling and neuroapoptosis were examined. We investigated whether neonatal exposure to sevo increased β-site APP-cleaving enzyme 1 (BACE-1) expression. Neonatal sevo exposure elevated caspase-3 activation. ER stress signaling was activated, along with increased PERK and eIF2α phosphorylation, and upregulation of proapoptotic proteins (ATF4 and CHOP) in the cerebral cortex of the developing brain. Pretreatment with salubrinal augmented sevo-induced eIF2α phosphorylation, which inhibited ER stress-mediated ATF4 and caspase-3 activation. Inhibition of PERK phosphorylation due to GSK2656157 pretreatment reduced the sevo-induced increase in eIF2α phosphorylation. Sevo increased BACE-1 expression, which was attenuated by GSK2656157 and salubrinal pretreatment. Our data suggested that neonatal sevo exposure-induced neuroapoptosis is mediated via the PERK-eIF2α-ATF4-CHOP axis of the ER stress signaling pathway. Modulation of eIF2α phosphorylation may play a key role in sevo-induced neurotoxicity in the developing brain.

Evaluation of lactic acid as an initial and secondary subprimal intervention for Escherichia coli O157:H7, non-O157 Shiga toxin-producing E. coli, and a nonpathogenic E. coli surrogate for E. coli O157:H7.

PubMed

Pittman, C I; Geornaras, I; Woerner, D R; Nightingale, K K; Sofos, J N; Goodridge, L; Belk, K E

2012-09-01

Lactic acid can reduce microbial contamination on beef carcass surfaces when used as a food safety intervention, but effectiveness when applied to the surface of chilled beef subprimal sections is not well documented. Studies characterizing bacterial reduction on subprimals after lactic acid treatment would be useful for validations of hazard analysis critical control point (HACCP) systems. The objective of this study was to validate initial use of lactic acid as a subprimal intervention during beef fabrication followed by a secondary application to vacuum-packaged product that was applied at industry operating parameters. Chilled beef subprimal sections (100 cm(2)) were either left uninoculated or were inoculated with 6 log CFU/cm(2) of a 5-strain mixture of Escherichia coli O157:H7, a 12-strain mixture of non-O157 Shiga toxin-producing E. coli (STEC), or a 5-strain mixture of nonpathogenic (biotype I) E. coli that are considered surrogates for E. coli O157:H7. Uninoculated and inoculated subprimal sections received only an initial or an initial and a second "rework" application of lactic acid in a custombuilt spray cabinet at 1 of 16 application parameters. After the initial spray, total inoculum counts were reduced from 6.0 log CFU/cm(2) to 3.6, 4.4, and 4.4 log CFU/cm(2) for the E. coli surrogates, E. coli O157:H7, and non-O157 STEC inoculation groups, respectively. After the second (rework) application, total inoculum counts were 2.6, 3.2, and 3.6 log CFU/cm(2) for the E. coli surrogates, E. coli O157:H7, and non-O157 STEC inoculation groups, respectively. Both the initial and secondary lactic acid treatments effectively reduced counts of pathogenic and nonpathogenic strains of E. coli and natural microflora on beef subprimals. These data will be useful to the meat industry as part of the HACCP validation process.

Evidence on the validity and reliability of the German, French and Italian nursing home version of the Basel Extent of Rationing of Nursing Care instrument.

PubMed

Zúñiga, Franziska; Schubert, Maria; Hamers, Jan P H; Simon, Michael; Schwendimann, René; Engberg, Sandra; Ausserhofer, Dietmar

2016-08-01

To develop and test psychometrically the Basel Extent of Rationing of Nursing Care for Nursing Homes instrument, providing initial evidence on the validity and reliability of the German, French and Italian-language versions. In the hospital setting, implicit rationing of nursing care is defined as the withholding of nursing activities due to lack of resources, such as staffing or time. No instrument existed to measure this concept in nursing homes. Cross-sectional study. We developed the instrument in three phases: (1) adaption and translation; (2) content validity testing; and (3) initial validity and reliability testing. For phase 3, we analysed survey data from 4748 care workers collected between May 2012-April 2013 from a randomly selected sample of 162 nursing homes in the German-, French- and Italian-speaking regions of Switzerland to provide evidence from response processes (e.g. missing), internal structure (exploratory factor analysis), inter-item inconsistencies (e.g. Cronbach's alpha) and interscorer differences (e.g. within-group agreement). Exploratory factor analysis revealed a four-factor structure with good fit statistics. Rationing of nursing care was structured in four domains: (1) activities of daily living; (2) caring, rehabilitation and monitoring; (3) documentation; and (4) social care. Items of the social care subscale showed lower content validity and more missing values than items of other subscales. First evidence indicates that the new instrument can be recommended for research and practice to measure implicit rationing of nursing care in nursing homes. Further refinements of single items are needed. © 2016 John Wiley & Sons Ltd.

Association of electronic cigarette use with initiation of combustible tobacco product smoking in early adolescence

PubMed Central

Leventhal, Adam M.; Strong, David R.; Kirkpatrick, Matthew G.; Unger, Jennifer B.; Sussman, Steve; Riggs, Nathaniel R.; Stone, Matthew D.; Khoddam, Rubin; Samet, Jonathan M.; Audrain-McGovern, Janet

2016-01-01

Importance Exposure to nicotine in electronic (e-) cigarettes is common among adolescents who report never having smoked combustible tobacco. Objectives To evaluate whether e-cigarette ever-use among 14-year-olds who have never tried combustible tobacco is associated with risk of initiating use of three combustible tobacco products (i.e., cigarettes, cigars, and hookah). Design Longitudinal repeated assessment of a school-based cohort at baseline (fall 2013, 9th grade, Mean age=14.1) and 6-month (spring 2014, 9th grade) and 12-month (fall 2014, 10th grade) follow-ups. Setting and Participants Ten public high schools in Los Angeles, CA were recruited through convenience sampling. Participants were students who reported never using combustible tobacco at baseline and underwent follow-up assessment (N=2,530). At each time point, students completed self-report surveys during in-classroom data collections. Exposure Self-report of e-cigarette ever-use (yes/no) at baseline. Main Outcome Measures Six- and 12-month follow-up reports of use of each of the following tobacco products within the prior 6 months: (1) any combustible tobacco product (yes/no); (2) combustible cigarettes (yes/no), (3) cigars (yes/no); (4) hookah (yes/no); and (5) number of combustible tobacco products (range: 0–3). Results Past 6-month use of any combustible tobacco product was more frequent in baseline e-cigarette ever-users (N=222) than never-users (N=2,308) at the 6-month (30.7% vs. 8.1%, % difference [95% CI]=22.7[16.4, 28.9]) and 12-month (25.2% vs. 9.3%, % difference [95% CI]= 15.9[10.0, 21.8]) follow-ups. Baseline ever e-cigarette use was associated with greater likelihood of combustible tobacco use averaged across the two follow-ups in unadjusted analyses (OR[95% CI]=4.27[3.19, 5.71]) and in analyses adjusted for sociodemographic, environmental, and intrapersonal risk factors for smoking (OR[95% CI]=2.73[2.00, 3.73]). Product-specific analyses showed that baseline e-cigarette ever-use was positively associated with combustible cigarette (OR[95% CI]=2.65[1.73, 4.05]), cigar (OR[95% CI]=4.85[3.38, 6.96]), and hookah (OR[95% CI]=3.25[2.29, 4.62]) use and number of different combustible products used (OR[95% CI]=4.26[3.16, 5.74]) averaged across the two follow-ups. Conclusion and Relevance Among high school students in Los Angeles, those who used electronic cigarettes at baseline compared with nonusers were more likely to report initiation of combustible tobacco smoking over the next year. Further research is needed to understand whether this association may be causal. PMID:26284721

La-related protein 1 (LARP1) repression of TOP mRNA translation is mediated through its cap-binding domain and controlled by an adjacent regulatory region

PubMed Central

Philippe, Lucas; Vasseur, Jean-Jacques; Debart, Françoise

2018-01-01

Abstract Cell growth is a complex process shaped by extensive and coordinated changes in gene expression. Among these is the tightly regulated translation of a family of growth-related mRNAs defined by a 5′ terminal oligopyrimidine (TOP) motif. TOP mRNA translation is partly controlled via the eukaryotic initiation factor 4F (eIF4F), a translation factor that recognizes the mRNA 5′ cap structure. Recent studies have also implicated La-related protein 1 (LARP1), which competes with eIF4F for binding to mRNA 5′ ends. However, it has remained controversial whether LARP1 represses TOP mRNA translation directly and, if so, what features define its mRNA targets. Here, we show that the C-terminal half of LARP1 is necessary and sufficient to control TOP mRNA translation in cells. This fragment contains the DM15 cap-binding domain as well as an adjacent regulatory region that we identified. We further demonstrate that purified LARP1 represses TOP mRNA translation in vitro through the combined recognition of both the TOP sequence and cap structure, and that its intrinsic repressive activity and affinity for these features are subject to regulation. These results support a model whereby the translation of TOP mRNAs is controlled by a growth-regulated competition between eIF4F and LARP1 for their 5′ ends. PMID:29244122

The Corfu Landslide: Analog to Giant Landslides on Mars

NASA Technical Reports Server (NTRS)

Lewis, S. W.; Baker, V. R.

1984-01-01

In an analog to the great landslides of the Vales Marineris, Mars, a detailed study was made of the Corfu Landslide in south-central Washington. This prehistoric slide is located on the northern flank of the Saddle Mountains, southwest of Othello, Washington. The slide covers a 13 square km area centered on section 11 of T.15N., R.27E., Willamette Meridian, adjacent to the Corfu townsite. Approximately 1 cubic km of material is involved in sliding that was probably initiated by Missoula flooding through the Channeled Scabland. It is concluded that there were four primary factors involved in the initiation of the Corfu landsliding: (1) A slip surface was present at the right orientation; (2) Glacial flooding undercut the slope; (3) Wetter climatic conditions prevailed during that time period; and (4) Some seismic vibrations, known to occur locally, probably acted as a trigger. These factors show that special conditions were required in conjunction to produce landsliding. Studies in progress of the Vales Marieneris suggest that the same factors probably contributed to landsliding there.

O-GlcNAcylation of eIF2α regulates the phospho-eIF2α-mediated ER stress response.

PubMed

Jang, Insook; Kim, Han Byeol; Seo, Hojoong; Kim, Jin Young; Choi, Hyeonjin; Yoo, Jong Shin; Kim, Jae-woo; Cho, Jin Won

2015-08-01

O-GlcNAcylation is highly involved in cellular stress responses including the endoplasmic reticulum (ER) stress response. For example, glucosamine-induced flux through the hexosamine biosynthetic pathway can promote ER stress and ER stress inducers can change the total cellular level of O-GlcNAcylation. However, it is largely unknown which component(s) of the unfolded protein response (UPR) is directly regulated by O-GlcNAcylation. In this study, eukaryotic translation initiation factor 2α (eIF2α), a major branch of the UPR, was O-GlcNAcylated at Ser 219, Thr 239, and Thr 241. Upon ER stress, eIF2α is phosphorylated at Ser 51 by phosphorylated PKR-like ER kinase and this inhibits global translation initiation, except for that of specific mRNAs, including activating transcription factor 4, that induce stress-responsive genes such as C/EBP homologous protein (CHOP). Hyper-O-GlcNAcylation induced by O-GlcNAcase inhibitor (thiamet-G) treatment or O-GlcNAc transferase (OGT) overexpression hindered phosphorylation of eIF2α at Ser 51. The level of O-GlcNAcylation of eIF2α was changed by dithiothreitol treatment dependent on its phosphorylation at Ser 51. Point mutation of the O-GlcNAcylation sites of eIF2α increased its phosphorylation at Ser 51 and CHOP expression and resulted in increased apoptosis upon ER stress. These results suggest that O-GlcNAcylation of eIF2α affects its phosphorylation at Ser 51 and influences CHOP-mediated cell death. This O-GlcNAcylation of eIF2α was reproduced in thiamet-G-injected mouse liver. In conclusion, proper regulation of O-GlcNAcylation and phosphorylation of eIF2α is important to maintain cellular homeostasis upon ER stress. Copyright © 2015 Elsevier B.V. All rights reserved.

Geographical Gradient of the eIF4E Alleles Conferring Resistance to Potyviruses in Pea (Pisum) Germplasm

PubMed Central

Konečná, Eva; Šafářová, Dana; Navrátil, Milan; Hanáček, Pavel; Coyne, Clarice; Flavell, Andrew; Vishnyakova, Margarita; Ambrose, Mike; Redden, Robert; Smýkal, Petr

2014-01-01

Background The eukaryotic translation initiation factor 4E was shown to be involved in resistance against several potyviruses in plants, including pea. We combined our knowledge of pea germplasm diversity with that of the eIF4E gene to identify novel genetic diversity. Methodology/Principal findings Germplasm of 2803 pea accessions was screened for eIF4E intron 3 length polymorphism, resulting in the detection of four eIF4EA-B-C-S variants, whose distribution was geographically structured. The eIF4EA variant conferring resistance to the P1 PSbMV pathotype was found in 53 accessions (1.9%), of which 15 were landraces from India, Afghanistan, Nepal, and 7 were from Ethiopia. A newly discovered variant, eIF4EB, was present in 328 accessions (11.7%) from Ethiopia (29%), Afghanistan (23%), India (20%), Israel (25%) and China (39%). The eIF4EC variant was detected in 91 accessions (3.2% of total) from India (20%), Afghanistan (33%), the Iberian Peninsula (22%) and the Balkans (9.3%). The eIF4ES variant for susceptibility predominated as the wild type. Sequencing of 73 samples, identified 34 alleles at the whole gene, 26 at cDNA and 19 protein variants, respectively. Fifteen alleles were virologically tested and 9 alleles (eIF4EA-1-2-3-4-5-6-7, eIF4EB-1, eIF4EC-2) conferred resistance to the P1 PSbMV pathotype. Conclusions/Significance This work identified novel eIF4E alleles within geographically structured pea germplasm and indicated their independent evolution from the susceptible eIF4ES1 allele. Despite high variation present in wild Pisum accessions, none of them possessed resistance alleles, supporting a hypothesis of distinct mode of evolution of resistance in wild as opposed to crop species. The Highlands of Central Asia, the northern regions of the Indian subcontinent, Eastern Africa and China were identified as important centers of pea diversity that correspond with the diversity of the pathogen. The series of alleles identified in this study provides the basis to study the co-evolution of potyviruses and the pea host. PMID:24609094

Retrospective epidemiological study of canine epilepsy in Japan using the International Veterinary Epilepsy Task Force classification 2015 (2003-2013): etiological distribution, risk factors, survival time, and lifespan.

PubMed

Hamamoto, Yuji; Hasegawa, Daisuke; Mizoguchi, Shunta; Yu, Yoshihiko; Wada, Masae; Kuwabara, Takayuki; Fujiwara-Igarashi, Aki; Fujita, Michio

2016-11-09

Epilepsy is the most common neurological disease in veterinary practice. However, contrary to human medicine, epilepsy classification in veterinary medicine had not been clearly defined until recently. A number of reports on canine epilepsy have been published, reflecting in part updated proposals from the human epilepsy organization, the International League Against Epilepsy. In 2015, the International Veterinary Epilepsy Task Force (IVETF) published a consensus report on the classification and definition of canine epilepsy. The purpose of this retrospective study was to investigate the etiological distribution, survival time of dogs with idiopathic epilepsy (IdE) and structural epilepsy (StE), and risk factors for survival time, according to the recently published IVETF classification. We investigated canine cases with epilepsy that were referred to our teaching hospital in Japan during the past 10 years, and which encompassed a different breed population from Western countries. A total of 358 dogs with epilepsy satisfied our etiological study criteria. Of these, 172 dogs (48 %) were classified as IdE and 76 dogs (21 %) as StE. Of these dogs, 100 dogs (consisting of 65 with IdE and 35 with StE) were included in our survival study. Median survival time from the initial epileptic seizure in dogs with IdE and StE was 10.4 and 4.5 years, respectively. Median lifespan of dogs with IdE and StE was 13.5 and 10.9 years, respectively. Multivariable analysis demonstrated that risk factors for survival time in IdE were high seizure frequency (≥0.3 seizures/month) and focal epileptic seizures. Focal epileptic seizures were identified as a risk factor for survival time in IdE. Clinicians should carefully differentiate seizure type as it is difficult to identify focal epileptic seizures. With good seizure control, dogs with IdE can survive for nearly the same lifespan as the general dog population. Our results using the IVETF classification are similar to previous studies, although some features were noted in our Japanese canine population (which was composed of mainly small-breed dogs), including a longer lifespan in dogs with epilepsy and a larger percentage of meningoencephalomyelitis of unknown origin in dogs with StE.

Skeletal involvement in Gaucher disease: An observational multicenter study of prognostic factors in the Argentine Gaucher disease patients.

PubMed

Drelichman, Guillermo; Fernández Escobar, Nicolás; Basack, Nora; Aversa, Luis; Larroude, María Silvia; Aguilar, Gabriela; Szlago, Marina; Schenone, Andrea; Fynn, Alcyra; Cuello, María Fernanda; Aznar, Marcela; Fernández, Ramiro; Ruiz, Alba; Reichel, Paola; Guelbert, Norberto; Robledo, Hugo; Watman, Nora; Bolesina, Moira; Elena, Graciela; Veber, S Ernesto; Pujal, Graciela; Galván, Graciela; Chain, Juan José; Arizo, Adriana; Bietti, Julieta; Bar, Daniel; Dragosky, Marta; Marquez, Marisa; Feldman, Leonardo; Muller, Katja; Zirone, Sandra; Buchovsky, Greogorio; Lanza, Victoria; Sanabria, Alba; Fernández, Ignacio; Jaureguiberry, Rossana; Contte, Marcelo; Barbieri María, Angie; Maro, Alejandra; Zárate, Graciela; Fernández, Gabriel; Rapetti, María Cristina; Donato, Hugo; Degano, Adriana; Kantor, Gustavo; Albina, Roberto; Á Lvarez Bollea, María; Brun, María; Bacciedoni, Viviana; Del Río, Francis; Soberón, Bárbara; Boido, Nazario; Schweri, Maya; Borchichi, Sandra; Welsh, Victoria; Corrales, Marcela; Cedola, Alejandra; Carvani, Analía; Diez, Blanca; Richard, Lucía; Baduel, Ccecilia; Nuñez, Gabriela; Colimodio, Rubén; Barazzutti, Lucía; Medici, Hugo; Meschengieser, Susana; Damiani, Germán; Nucifora, María; Girardi, Beatriz; Gómez, Sergio; Papucci, Maura; Verón, David; Quiroga, Luis; Carro, Gustavo; De Ambrosio, Patricia; Ferro, José; Pujol, Marcelo; Castella, Cristina Cabral; Franco, Liliana; Nisnovich, Gisela; Veloso, María; Pacheco, Isabel; Savarino, Mario; Marino, Andrés; Saavedra, José Luis

2016-10-01

Patients with Gaucher type 1 (GD1) throughout Argentina were enrolled in the Argentine bone project to evaluate bone disease and its determinants. We focused on presence and predictors of bone lesions (BL) and their relationship to therapeutic goals (TG) with timing and dose of enzyme replacement therapy (ERT). A total of 124 patients on ERT were enrolled in a multi-center study. All six TG were achieved by 82% of patients: 70.1% for bone pain and 91.1% for bone crisis. However, despite the fact that bone TGs were achieved, residual bone disease was present in 108 patients on ERT (87%) at time 0. 16% of patients showed new irreversible BL (bone infarcts and avascular osteonecrosis) despite ERT, suggesting that they appeared during ERT or were not detected at the moment of diagnosis. We observed 5 prognostic factors that predicted a higher probability of being free of bone disease: optimal ERT compliance; early diagnosis; timely initiation of therapy; ERT initiation dose ≥45 UI/kg/EOW; and the absence of history of splenectomy. Skeletal involvement was classified into 4 major phenotypic groups according to BL: group 1 (12.9%) without BL; group 2 (28.2%) with reversible BL; group 3 (41.9%) with reversible BL and irreversible chronic BL; and group 4 (16.9%) with acute irreversible BL. Our study identifies prognostic factors for achieving best therapeutic outcomes, introduces new risk stratification for patients and suggests the need for a redefinition of bone TG. Am. J. Hematol. 91:E448-E453, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

FBXO32 suppresses breast cancer tumorigenesis through targeting KLF4 to proteasomal degradation.

PubMed

Zhou, H; Liu, Y; Zhu, R; Ding, F; Wan, Y; Li, Y; Liu, Z

2017-06-08

Krüppel-like factor 4 (KLF4, GKLF) is a zinc-finger transcription factor involved in a large variety of cellular processes, including apoptosis, cell cycle progression, as well as stem cell renewal. KLF4 is critical for cell fate decision and has an ambivalent role in tumorigenesis. Emerging data keep reminding us that KLF4 dysregulation either facilitates or impedes tumor progression, making it important to clarify the regulating network of KLF4. Like most transcription factors, KLF4 has a rather short half-life within the cell and its turnover must be carefully orchestrated by ubiquitination and ubiquitin-proteasome system. To better understand the mechanism of KLF4 ubiquitination, we performed a genome-wide screen of E3 ligase small interfering RNA library based on western blot and identified SCF-FBXO32 to be a new E3 ligase, which is responsible for KLF4 ubiquitination and degradation. The F-box domain is critical for FBXO32-dependent KLF4 ubiquitination and degradation. Furthermore, we demonstrated that FBXO32 physically interacts with the N-terminus (1-60 aa) of KLF4 via its C-terminus (228-355 aa) and directly targets KLF4 for ubiquitination and degradation. We also found out that p38 mitogen-activated protein kinase pathway may be implicated in FBXO32-mediated ubiquitination of KLF4, as p38 kinase inhibitor coincidently abrogates endogenous KLF4 ubiquitination and degradation, as well as FBXO32-dependent exogenous KLF4 ubiquitination and degradation. Finally, FBXO32 inhibits colony formation in vitro and primary tumor initiation and growth in vivo through targeting KLF4 into degradation. Our findings thus further elucidate the tumor-suppressive function of FBXO32 in breast cancer. These results expand our understanding of the posttranslational modification of KLF4 and of its role in breast cancer development and provide a potential target for diagnosis and therapeutic treatment of breast cancer.

Molecular Architecture of the 40S⋅eIF1⋅eIF3 Translation Initiation Complex

PubMed Central

Erzberger, Jan P.; Stengel, Florian; Pellarin, Riccardo; Zhang, Suyang; Schaefer, Tanja; Aylett, Christopher H.S.; Cimermančič, Peter; Boehringer, Daniel; Sali, Andrej; Aebersold, Ruedi; Ban, Nenad

2014-01-01

Summary Eukaryotic translation initiation requires the recruitment of the large, multiprotein eIF3 complex to the 40S ribosomal subunit. We present X-ray structures of all major components of the minimal, six-subunit Saccharomyces cerevisiae eIF3 core. These structures, together with electron microscopy reconstructions, cross-linking coupled to mass spectrometry, and integrative structure modeling, allowed us to position and orient all eIF3 components on the 40S⋅eIF1 complex, revealing an extended, modular arrangement of eIF3 subunits. Yeast eIF3 engages 40S in a clamp-like manner, fully encircling 40S to position key initiation factors on opposite ends of the mRNA channel, providing a platform for the recruitment, assembly, and regulation of the translation initiation machinery. The structures of eIF3 components reported here also have implications for understanding the architecture of the mammalian 43S preinitiation complex and the complex of eIF3, 40S, and the hepatitis C internal ribosomal entry site RNA. PMID:25171412

Phylogenetic analysis of eIF4E-family members

PubMed Central

Joshi, Bhavesh; Lee, Kibwe; Maeder, Dennis L; Jagus, Rosemary

2005-01-01

Background Translation initiation in eukaryotes involves the recruitment of mRNA to the ribosome which is controlled by the translation factor eIF4E. eIF4E binds to the 5'-m7Gppp cap-structure of mRNA. Three dimensional structures of eIF4Es bound to cap-analogues resemble 'cupped-hands' in which the cap-structure is sandwiched between two conserved Trp residues (Trp-56 and Trp-102 of H. sapiens eIF4E). A third conserved Trp residue (Trp-166 of H. sapiens eIF4E) recognizes the 7-methyl moiety of the cap-structure. Assessment of GenBank NR and dbEST databases reveals that many organisms encode a number of proteins with homology to eIF4E. Little is understood about the relationships of these structurally related proteins to each other. Results By combining sequence data deposited in the Genbank databases, we have identified sequences encoding 411 eIF4E-family members from 230 species. These sequences have been deposited into an internet-accessible database designed for sequence comparisons of eIF4E-family members. Most members can be grouped into one of three classes. Class I members carry Trp residues equivalent to Trp-43 and Trp-56 of H. sapiens eIF4E and appear to be present in all eukaryotes. Class II members, possess Trp→Tyr/Phe/Leu and Trp→Tyr/Phe substitutions relative to Trp-43 and Trp-56 of H. sapiens eIF4E, and can be identified in Metazoa, Viridiplantae, and Fungi. Class III members possess a Trp residue equivalent to Trp-43 of H. sapiens eIF4E but carry a Trp→Cys/Tyr substitution relative to Trp-56 of H. sapiens eIF4E, and can be identified in Coelomata and Cnidaria. Some eIF4E-family members from Protista show extension or compaction relative to prototypical eIF4E-family members. Conclusion The expansion of sequenced cDNAs and genomic DNAs from all eukaryotic kingdoms has revealed a variety of proteins related in structure to eIF4E. Evolutionarily it seems that a single early eIF4E gene has undergone multiple gene duplications generating multiple structural classes, such that it is no longer possible to predict function from the primary amino acid sequence of an eIF4E-family member. The variety of eIF4E-family members provides a source of alternatives on the eIF4E structural theme that will benefit structure/function analyses and therapeutic drug design. PMID:16191198

Prostaglandin E2-stimulated prostanoid EP4 receptors induce prolonged de novo prostaglandin E2 synthesis through biphasic phosphorylation of extracellular signal-regulated kinases mediated by activation of protein kinase A in HCA-7 human colon cancer cells.

PubMed

Fujino, Hiromichi; Seira, Naofumi; Kurata, Naoki; Araki, Yumi; Nakamura, Hiroyuki; Regan, John W; Murayama, Toshihiko

2015-12-05

Approximately two decades have passed since E-type prostanoid 4 (EP4) receptors were cloned, and the signaling pathways mediated by these receptors have since been implicated in cancer development through the alliance of Gαi-protein/phosphatidylinositol 3-kinase (PI3K)/extracellular signal-regulated kinases (ERKs) activation. Although prostanoid EP4 receptors were initially identified as Gαs-coupled receptors, the specific/distinctive role(s) of prostanoid EP4 receptor-induced cAMP/protein kinase A (PKA) pathways in cancer development have not yet been elucidated in detail. We previously reported using HCA-7 human colon cancer cells that prostaglandin E2 (PGE2)-stimulated prostanoid EP4 receptors induced cyclooxygenase-2 (COX-2) as an initiating event in development of colon cancer. Moreover, this induction of COX-2 was mediated by transactivation of epidermal growth factor (EGF) receptors. However, direct activation of EGF receptors by EGF also induced similar amounts of COX-2 in this cell line. Thus, the emergence of unique role(s) for prostanoid EP4 receptors is expected by clarifying the different signaling mechanisms between PGE2-stimulated prostanoid EP4 receptors and EGF-stimulated EGF receptors to induce COX-2 and produce PGE2. We here demonstrated that prostanoid EP4 receptor activation by PGE2 in HCA-7 cells led to PKA-dependent re-activation of ERKs, which resulted in prolonged de novo synthesis of PGE2. Although EGF-stimulated EGF receptors in cells also induced COX-2 and the de novo synthesis of PGE2, the activation of this pathway was transient and not mediated by PKA. Therefore, the novel mechanism underlying prolonged de novo synthesis of PGE2 has provided an insight into the importance of prostanoid EP4 receptor-mediated Gαs-protein/cAMP/PKA pathway in development of colon cancer. Copyright © 2015 Elsevier B.V. All rights reserved.

Synergistic effect of ozonation and ionizing radiation for PVA decomposition.

PubMed

Sun, Weihua; Chen, Lujun; Zhang, Yongming; Wang, Jianlong

2015-08-01

Ozonation and ionizing radiation are both advanced oxidation processes (AOPs) without chemical addition and secondary pollution. Also, the two processes' efficiency is determined by different pH conditions, which creates more possibilities for their combination. Importantly, the combined process of ozonation and ionizing radiation could be suitable for treating wastewaters with extreme pH values, i.e., textile wastewater. To find synergistic effects, the combined process of ozonation and ionizing radiation mineralization was investigated for degradation of polyvinyl alcohol (PVA) at different pH levels. A synergistic effect was found at initial pH in the range 3.0-9.4. When the initial pH was 3.0, the combined process of ozonation and ionizing radiation gave a PVA mineralization degree of 17%. This was 2.7 times the sum achieved by the two individual processes, and factors of 2.1 and 1.7 were achieved at initial pH of 7.0 and 9.4, respectively. The combined process of ozonation and ionizing radiation was demonstrated to be a feasible strategy for treatment of PVA-containing wastewater. Copyright © 2015. Published by Elsevier B.V.

Risk Factors for the Development of Gastrointestinal Colonization With Fluoroquinolone-Resistant Escherichia coli in Residents of Long-Term Care Facilities

PubMed Central

Han, Jennifer H.; Maslow, Joel; Han, Xiaoyan; Xie, Sharon X.; Tolomeo, Pam; Santana, Evelyn; Carson, Lesley; Lautenbach, Ebbing

2014-01-01

Background. The objective of this study was to assess risk factors for the development of fluoroquinolone (FQ)–resistant Escherichia coli gastrointestinal tract colonization in long-term care facility (LTCF) residents. Methods. A prospective cohort study was conducted from 2006 to 2008 at 3 LTCFs. Residents initially colonized with FQ-susceptible E. coli were followed by means of serial fecal sampling for new FQ-resistant E. coli colonization for up to 12 months or until discharge or death. A Cox proportional hazards regression model was developed to identify risk factors for new FQ-resistant E. coli colonization, with antibiotic and device exposures modeled as time-varying covariates. Results. Fifty-seven (47.5%) of 120 residents became newly colonized with FQ-resistant E. coli, with a median time to colonization of 57 days. Fecal incontinence (hazard ratio [HR], 1.78; 95% confidence interval [CI], 1.04–3.06; P = .04) was significantly associated with FQ-resistant E. coli acquisition. Receipt of amoxicillin-clavulanate (HR, 6.48; 95% CI, 1.43–29.4; P = .02) and the presence of a urinary catheter (HR, 3.81; 95% CI, 1.06–13.8; P = .04) during LTCF stay increased the risk of new FQ-resistant E. coli colonization. Conclusions. Acquisition of FQ-resistant E. coli was common, with nearly half of LTCF residents developing new FQ-resistant E. coli colonization. Further studies are needed on interventions to limit the emergence of FQ-resistant E. coli in LTCFs. PMID:23986544

Regulation of eIF2α phosphorylation in hindlimb-unloaded and STS-135 space-flown mice

NASA Astrophysics Data System (ADS)

Zhao, Liming; Tanjung, Nancy; Swarnkar, Gaurav; Ledet, Eric; Yokota, Hiroki

2012-09-01

Various environmental stresses elevate the phosphorylation level of eukaryotic translation initiation factor 2 alpha (eIF2α) and induce transcriptional activation of a set of stress responsive genes such as activating transcription factors 3 and 6 (ATF3 and ATF6), CCAAT/enhancer-binding protein homologous protein (CHOP), and Xbp1 (X-box binding protein 1). These stress sources include radiation, oxidation, and stress to the endoplasmic reticulum, and it is recently reported that unloading by hindlimb unloading is such a stress source. No studies, however, have examined the phosphorylation level of eIF2α (eIF2α-p) using skeletal samples that have experienced microgravity in space. In this study we addressed a question: Does a mouse tibia flown in space show altered levels of eIF2α-p? To address this question, we obtained STS-135 flown samples that were harvested 4-7 h after landing. The tibia and femur isolated from hindlimb unloaded mice were employed as non-flight controls. The effects of loading were also investigated in non- flight controls. Results indicate that the level of eIF2α-p of the non-flight controls was elevated during hindlimb unloading and reduced after being released from unloading. Second, the eIF2α-p level of space-flown samples was decreased, and mechanical loading to the tibia caused the reduction of the eIF2α-p level. Third, the mRNA levels of ATF3, ATF6, and CHOP were lowered in space-flown samples as well as in the non-flight samples 4-7 h after being released from unloading. Collectively, the results herein indicated that a release from hindlimb unloading and a return to normal weight environment from space provided a suppressive effect to eIF2α-linked stress responses and that a period of 2-4 h is sufficient to induce this suppressive outcome.

Computer Simulation of Ejection Seat Performance and Preliminary Correlation with Empirical Data

DTIC Science & Technology

1980-04-01

L. . .. . 3 I r AFFDL-TR-79-31 50 TABLE OF CONTENTS SECTION PAGE I INTRODUCTION 1 1I SAFEST COMPUTER PROGRAM DESCRIPTION 8 III HITECH ...ZEARTH vs TIME 49E-I1A 53 34 ZEARTH vs XEARTH 49E-IIA 54 AFFDL-TR-79-3150 LIST OF TABLES TABLE PAGE 1 ACES II EVENT-TIME SEQUENCE 3 2 HITECH 49E-JlF...Initial Conditions 13 3 HITECH 49E-I1A Initial Conditions 14 4 HITECH Program Test Data Summary 15 5 SAFEST 49E-JIF Initial Conditions 20 6 SAFEST 49E-IIA

Hepatic translation control in the late-gestation fetal rat.

PubMed

Gruppuso, Philip A; Tsai, Shu-Whei; Boylan, Joan M; Sanders, Jennifer A

2008-08-01

We have investigated the regulation of translation during the period of rapid liver growth that occurs at the end of gestation in the rat. This work was based on our prior observation that fetal hepatocyte proliferation is resistant to the inhibitory effects of rapamycin, an inhibitor of the mammalian target of rapamycin (mTOR), a nutrient-sensing kinase that controls ribosome biogenesis and protein translation. We hypothesized that translation control in late-gestation fetal liver differs from that in adult liver. We first examined the ability of rapamycin to inhibit the translation of mRNAs encoding ribosomal proteins. Consistent with the effect of rapamycin on proliferation, the activation of adult liver 5'-terminal oligopyrimidine tracts (5'-TOP) translation that occurred during refeeding after food deprivation was sensitive to rapamycin. Fetal liver 5'-TOP translation was insensitive. We went on to examine the eukaryotic initiation factor (eIF) 4F cap-binding complex that controls global protein synthesis. The molecular weights of the multiple eIF4G1 isoforms present in fetal and adult liver eIF4F complexes differed. In addition, fetal liver expressed the eIF4A1 form of the eIF4A helicase, whereas adult liver contained eIF4A1 and eIF4A2. Rapamycin administration before refeeding in adult rats inhibited formation of the preinitiation complex to a much greater degree than rapamycin administration to fetal rats in situ. We conclude that there are major structural and functional differences in translation control between late-gestation fetal and adult liver. These differences may confer differential sensitivity to the growth inhibitory effects of rapamycin.

Association Between Short Sleep Duration and Risk Behavior Factors in Middle School Students.

PubMed

Owens, Judith; Wang, Guanghai; Lewin, Daniel; Skora, Elizabeth; Baylor, Allison

2017-01-01

To examine the association between self-reported sleep duration (SD) and peer/individual factors predictive of risky behaviors (risk behavior factors) in a large socioeconomically diverse school-based sample of early adolescents. Survey data collected from 10718 and 11240 eighth-grade students in 2010 and 2012, respectively, were analyzed. N/A. Self-reported school night SD was grouped as ≤4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, and ≥10 hours. Scores on 10 peer/individual risk behavior factor scales were dichotomized according to national eigth-grade cut points. The percentage of students reporting an "optimal" SD of 9 hours was 14.8% and 15.6% in 2010 and 2012, respectively; 45.6% and 46.1% reported <7 hours. Adjusted for covariates of gender, race, and SES, multilevel logistic regression results showed that odds ratios (ORs) for 9 of 10 risk factor scales increased with SD <7 hours, with a dose-response effect for each hour less sleep compared to an SD of 9 hours. For example, ORs for students sleeping <7 hours ranged from 1.3 (early initiation of antisocial behavior) to 1.8 (early initiation of drug use). The risk factor scale ORs for <5 hours SD ranged from 3.0 (sensation seeking) to 6.4 (gang involvement). Middle school students are at high risk of insufficient sleep; in particular, an SD <7 hours is associated with increased risk behavior factors. © Sleep Research Society 2016. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

Impact of genetic factors on dyslipidemia in HIV-infected patients starting antiretroviral therapy.

PubMed

Egaña-Gorroño, Lander; Martínez, Esteban; Cormand, Bru; Escribà, Tuixent; Gatell, Jose; Arnedo, Mireia

2013-02-20

The impact of host genetic factors on the incidence of dyslipidemia in antiretroviral-naive HIV patients starting antiretroviral therapy (ART) is not clear. We assessed the role of single nucleotide polymorphisms (SNPs) identified from previous genome-wide association studies adjusting for the contribution of nongenetic factors. We assessed 192 SNPs in an HIV cohort who started ART (1997-2008) including a protease inhibitor or a nonnucleoside reverse transcriptase inhibitor (NNRTI). Patients had fasting plasma lipids, total cholesterol (T-Chol), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides measured prior to their ART initiation and after 1 year. A logistic regression model was constructed and multiple test was corrected using 10% false discovery rate (FDR). Haplotypes and gene interactions were analysed. A total of 727 individuals were successfully genotyped (n = 381_PI-group; n = 346_NNRTI-group). Age and hepatitis C virus (HCV) coinfection were associated with increases and decreases in T-Chol and LDL-C (P < 0.01), respectively. Protease inhibitor containing ART showed an unfavourable association with T-Chol (P < 0.01) and triglycerides (P = 7.4E-4) and NNRTI-containing ART was favourably associated with HDL-C (P < 0.01). Moreover, SNPs in apolipoprotein B (APOB) were associated with an increase of LDL-C [rs10495712 (P = 3.18E-4); rs754524 (P = 1.26E-3)]. Six SNPs in three genes showed an association with a favourable effect on HDL-C levels when ART included NNRTI: ABCA1 (rs4149313, P = 2.97E-4), LIPC (rs1800588, P = 2.13E-3; rs473224, P = 3.06E-4; rs261336, P = 2.23E-3) and CETP (rs173539, P = 2.96E-3; rs3764261, P = 1.52E-3). After 10% FDR correction for multiple testing, one and six SNPs displayed significant associations with LDL-C and HDL-C, respectively. In HIV-infected patients staring ART, one SNP in APOB was associated with an increase of LDL-C. SNPs in ABCA1/LIPC/CETP were favourably associated with HDL-C when ART included NNRTI. However, an unfavourable effect on T-Chol and triglyceride levels was observed when ART included protease inhibitor. The risk of hypercholesterolaemia increased with age and decreased with HCV coinfection. These findings might help to individualize the selection of ART.

Mitochondrial translational-initiation and elongation factors in Saccharomyces cerevisiae.

PubMed

Vambutas, A; Ackerman, S H; Tzagoloff, A

1991-11-01

C155 and E252 are respiratory-defective mutants of Saccharomyces cerevisiae, previously assigned to complementation groups G37 and G142, respectively. The following evidence suggested that both mutants were likely to have lesions in components of the mitochondrial translational machinery: C155 and E252 display a pleiotropic deficiency in cytochromes a, a3 and b; both strains are severly limited in their ability to incorporate radioactive methionine into the mitochondrial translation products and, in addition, display a tendency to loose wild-type mitochondrial DNA. This set of characteristics is commonly found in strains affected in mitochondrial protein synthesis. To identify the biochemical lesions, each mutant was transformed with a wild-type yeast genomic library and clones complemented for the respiratory defect were selected for growth on a non-fermentable substrate. Analysis of the cloned genes revealed that C155 has a mutation in a protein which has high sequence similarity to bacterial elongation factor G and that E252 has a mutation in a protein homologous to bacterial initiation factor 2. Disruption of the chromosomal copy of each gene in a wild-type haploid yeast induced a phenotype analogous to that of the original mutants, but does not affect cell viability. These results indicate that both gene products function exclusively in mitochondrial protein synthesis. Subcloning of the IFM1 gene, coding for the mitochondrial initiation factor, indicates that the amino-terminal 423 residues of the protein are sufficient to promote peptide-chain initiation in vivo.

Endoplasmic reticulum stress-mediated neuronal apoptosis by acrylamide exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Komoike, Yuta, E-mail: komoike@research.twmu.ac.jp

Acrylamide (AA) is a well-known neurotoxic compound in humans and experimental animals. However, intracellular stress signaling pathways responsible for the neurotoxicity of AA are still not clear. In this study, we explored the involvement of the endoplasmic reticulum (ER) stress response in AA-induced neuronal damage in vitro and in vivo. Exposure of SH-SY5Y human neuroblastoma cells to AA increased the levels of phosphorylated form of eukaryotic translation initiation factor 2α (eIF2α) and its downstream effector, activating transcription factor 4 (ATF4), indicating the induction of the unfolded protein response (UPR) by AA exposure. Furthermore, AA exposure increased the mRNA level ofmore » c/EBP homologous protein (CHOP), the ER stress-dependent apoptotic factor, and caused the accumulation of reactive oxygen species (ROS) in SH-SY5Y cells. Treatments of SH-SY5Y cells with the chemical chaperone, 4-phenylbutyric acid and the ROS scavenger, N-acetyl-cysteine reduced the AA-induced expression of ATF4 protein and CHOP mRNA, and resulted in the suppression of apoptosis. In addition, AA-induced eIF2α phosphorylation was also suppressed by NAC treatment. In consistent with in vitro study, exposure of zebrafish larvae at 6-day post fertilization to AA induced the expression of chop mRNA and apoptotic cell death in the brain, and also caused the disruption of brain structure. These findings suggest that AA exposure induces apoptotic neuronal cell death through the ER stress and subsequent eIF2α–ATF4–CHOP signaling cascade. The accumulation of ROS by AA exposure appears to be responsible for this ER stress-mediated apoptotic pathway. - Highlights: • Exposure of SH-SY5Y cells to AA activates the eIF2α–ATF4 pathway of the UPR. • Exposure of SH-SY5Y cells to AA induces the CHOP expression and apoptosis. • Exposure of zebrafish to AA induces the chop expression and apoptosis in the brain. • AA possibly induces apoptotic neuronal cell death through the ER stress response. • AA-induced ROS production is involved in this ER stress response.« less

A Prospective Trial on Initiation Factor 4E (eIF4E) Overexpression and Cancer Recurrence in Node-Positive Breast Cancer

PubMed Central

McClusky, Derek R.; Chu, Quyen; Yu, Herbert; DeBenedetti, Arrigo; Johnson, Lester W.; Meschonat, Carol; Turnage, Richard; McDonald, John C.; Abreo, Fleurette; Li, Benjamin D. L.

2005-01-01

Objective: A previous study of patients with stage I to III breast cancer showed that those patients whose tumors were in the highest tertile of eIF4E overexpression experienced a higher risk for recurrence. This study was designed to determine whether high eIF4E overexpression predicts cancer recurrence independent of nodal status by specifically targeting patients with node-positive disease. Methods: The prospective trial was designed to accrue 168 patients with node-positive breast cancer to detect a 2.5-fold increase in risk for recurrence. eIF4E level was quantified by Western blots as x-fold elevated compared with breast tissues from noncancer patients. End points measured were disease recurrence and cancer-related death. Statistical analyses performed include survival analysis by the Kaplan-Meier method, log-rank test, and Cox proportional hazard model. Results: One hundred seventy-four patients with node-positive breast cancer were accrued. All patients fulfilled study inclusion and exclusion criteria, treatment protocol, and surveillance requirements, with a compliance rate >95%. The mean eIF4E elevation was 11.0 ± 7.0-fold (range, 1.4–34.3-fold). Based on previously published data, tertile distribution was as follow: 1) lowest tertile (<7.5-fold) = 67 patients, 2) intermediate tertile (7.5–14-fold) = 54 patients, and 3) highest tertile (>14-fold) = 53 patients. At a median follow up of 32 months, patients with the highest tertile had a statistically significant higher cancer recurrence rate (log-rank test, P = 0.002) and cancer-related death rate (P = 0.036) than the lowest group. Relative risk calculations demonstrated that high eIF4E patients had a 2.4-fold increase in relative risk increase for cancer recurrence (95% confidence interval, 1.2–4.1; P = 0.01). Conclusions: In this prospective study designed to specifically address risk for recurrence in patients with node-positive breast cancer, the patients whose tumors were in the highest tertile of eIF4E overexpression had a 2.4-fold increase in relative risk for cancer recurrence. Therefore, eIF4E overexpression appears to be an independent predictor of a worse outcome in patients with breast cancer independent of nodal status. PMID:16192819

Replication initiator protein RepE of mini-F plasmid: functional differentiation between monomers (initiator) and dimers (autogenous repressor).

PubMed Central

Ishiai, M; Wada, C; Kawasaki, Y; Yura, T

1994-01-01

Replication of mini-F plasmid requires the plasmid-encoded RepE initiator protein and several host factors including DnaJ, DnaK, and GrpE, heat shock proteins of Escherichia coli. The RepE protein plays a crucial role in replication and exhibits two major functions: initiation of replication from the origin, ori2, and autogenous repression of repE transcription. One of the mini-F plasmid mutants that can replicate in the dnaJ-defective host produces an altered RepE (RepE54) with a markedly enhanced initiator activity but little or no repressor activity. RepE54 has been purified from cell extracts primarily in monomeric form, unlike the wild-type RepE that is recovered in dimeric form. Gel-retardation assays revealed that RepE54 monomers bind to ori2 (direct repeats) with a very high efficiency but hardly bind to the repE operator (inverted repeat), in accordance with the properties of RepE54 in vivo. Furthermore, the treatment of wild-type RepE dimers with protein denaturants enhanced their binding to ori2 but reduced binding to the operator: RepE dimers were partially converted to monomers, and the ori2 binding activity was uniquely associated with monomers. These results strongly suggest that RepE monomers represent an active form by binding to ori2 to initiate replication, whereas dimers act as an autogenous repressor by binding to the operator. We propose that RepE is structurally and functionally differentiated and that monomerization of RepE dimers, presumably mediated by heat shock protein(s), activates the initiator function and participates in regulation of mini-F DNA replication. Images PMID:8170998

Nucleosynthesis in the Innermost Ejecta of Neutrino-driven Supernova Explosions in Two Dimensions

NASA Astrophysics Data System (ADS)

Wanajo, Shinya; Müller, Bernhard; Janka, Hans-Thomas; Heger, Alexander

2018-01-01

We examine nucleosynthesis in the innermost neutrino-processed ejecta (a few {10}-3 {M}ȯ ) of self-consistent two-dimensional explosion models of core-collapse supernovae (CCSNe) for six progenitor stars with different initial masses. Three models have initial masses near the low-mass end of the SN range of 8.8 {M}ȯ (e8.8; electron-capture SN), 9.6 {M}ȯ (z9.6), and 8.1 {M}ȯ (u8.1), with initial metallicities of 1, 0, and 10‑4 times the solar metallicity, respectively. The other three are solar-metallicity models with initial masses of 11.2 {M}ȯ (s11), 15 {M}ȯ (s15), and 27 {M}ȯ (s27). The low-mass models e8.8, z9.6, and u8.1 exhibit high production factors (nucleosynthetic abundances relative to the solar abundances) of 100–200 for light trans-Fe elements from Zn to Zr. This is associated with an appreciable ejection of neutron-rich matter in these models. Remarkably, the nucleosynthetic outcomes for the progenitors e8.8 and z9.6 are almost identical, including interesting productions of 48Ca and 60Fe, irrespective of their quite different (O–Ne–Mg and Fe) cores prior to collapse. In the more massive models s11, s15, and s27, several proton-rich isotopes of light trans-Fe elements including the p-isotope 92Mo (for s27) are made, up to production factors of ∼30. Both electron-capture SNe and CCSNe near the low-mass end can therefore be dominant contributors to the Galactic inventory of light trans-Fe elements from Zn to Zr and probably 48Ca and live 60Fe. The innermost ejecta of more massive SNe may have only subdominant contributions to the chemical enrichment of the Galaxy except for 92Mo.

The HPV16 E7 oncoprotein increases the expression of Oct3/4 and stemness-related genes and augments cell self-renewal.

PubMed

Organista-Nava, Jorge; Gómez-Gómez, Yazmín; Ocadiz-Delgado, Rodolfo; García-Villa, Enrique; Bonilla-Delgado, José; Lagunas-Martínez, Alfredo; Tapia, Jesús Santa-Olalla; Lambert, Paul F; García-Carrancá, Alejandro; Gariglio, Patricio

2016-12-01

Oct3/4 is a transcription factor involved in maintenance of the pluripotency and self-renewal of stem cells. The E7 oncoprotein and 17β-estradiol (E 2 ) are key factors in cervical carcinogenesis. In the present study, we aimed to investigate the effect of the HPV16 E7 oncoprotein and E 2 on the expression pattern of Oct3/4, Sox2, Nanog and Fgf4. We also determined whether the E7 oncoprotein is associated with cell self-renewal. The results showed that Oct3/4, Sox2, Nanog and Fgf4 were upregulated by the E7 oncoprotein in vivo and in vitro and implicate E 2 in the upregulation of these factors in vivo. We also demonstrated that E7 is involved in cell self-renewal, suggesting that the HPV16 E7 oncoprotein upregulates Oct3/4, Sox2, Nanog and Fgf4 expression to maintain the self-renewal capacity of cancer stem cells. Copyright © 2016 Elsevier Inc. All rights reserved.

NPV-LDE-225 (Erismodegib) inhibits epithelial mesenchymal transition and self-renewal of glioblastoma initiating cells by regulating miR-21, miR-128, and miR-200.

PubMed

Fu, Junsheng; Rodova, Mariana; Nanta, Rajesh; Meeker, Daniel; Van Veldhuizen, Peter J; Srivastava, Rakesh K; Shankar, Sharmila

2013-06-01

Glioblastoma multiforme is the most common form of primary brain tumor, often characterized by poor survival. Glioblastoma initiating cells (GICs) regulate self-renewal, differentiation, and tumor initiation properties and are involved in tumor growth, recurrence, and resistance to conventional treatments. The sonic hedgehog (SHH) signaling pathway is essential for normal development and embryonic morphogenesis. The objectives of this study were to examine the molecular mechanisms by which GIC characteristics are regulated by NPV-LDE-225 (Smoothened inhibitor; (2,2'-[[dihydro-2-(4-pyridinyl)-1,3(2H,4H)-pyrimidinediyl]bis(methylene)]bis[N,N-dimethylbenzenamine). Cell viability and apoptosis were measured by XTT and annexin V-propidium iodide assay, respectively. Gli translocation and transcriptional activities were measured by immunofluorescence and luciferase assay, respectively. Gene and protein expressions were measured by quantitative real-time PCR and Western blot analyses, respectively. NPV-LDE-225 inhibited cell viability, neurosphere formation, and Gli transcriptional activity and induced apoptosis by activation of caspase-3 and cleavage of poly(ADP-ribose) polymerase. NPV-LDE-225 increased the expression of tumor necrosis factor-related apoptosis inducing ligand (TRAIL)-R1/DR4, TRAIL-R2/DR5, and Fas and decreased the expression of platelet derived growth factor receptor-α and Bcl2, and these effects were abrogated by Gli1 plus Gli2 short hairpin RNAs. NPV-LDE-225 enhanced the therapeutic potential of FasL and TRAIL by upregulating Fas and DR4/5, respectively. Interestingly, NPV-LDE-225 induced expression of programmed cell death 4 and apoptosis and inhibited cell viability by suppressing micro RNA (miR)-21. Furthermore, NPV-LDE-225 inhibited pluripotency-maintaining factors Nanog, Oct4, Sox2, and cMyc. The inhibition of Bmi1 by NPV-LDE-225 was regulated by induction of miR-128. Finally, NPV-LDE-225 suppressed epithelial-mesenchymal transition by upregulating E-cadherin and inhibiting N-cadherin, Snail, Slug, and Zeb1 through modulating the miR-200 family. Our data highlight the importance of the SHH pathway for self-renewal and early metastasis of GICs.

Effects of sex steroids on expression of genes regulating growth-related mechanisms in rainbow trout (Oncorhynchus mykiss).

PubMed

Cleveland, Beth M; Weber, Gregory M

2015-05-15

Effects of a single injection of 17β-estradiol (E2), testosterone (T), or 5β-dihydrotestosterone (DHT) on expression of genes central to the growth hormone (GH)/insulin-like growth factor (IGF) axis, muscle-regulatory factors, transforming growth factor-beta (TGFβ) superfamily signaling cascade, and estrogen receptors were determined in rainbow trout (Oncorhynchus mykiss) liver and white muscle tissue. In liver in addition to regulating GH sensitivity and IGF production, sex steroids also affected expression of IGF binding proteins, as E2, T, and DHT increased expression of igfbp2b and E2 also increased expression of igfbp2 and igfbp4. Regulation of this system also occurred in white muscle in which E2 increased expression of igf1, igf2, and igfbp5b1, suggesting anabolic capacity may be maintained in white muscle in the presence of E2. In contrast, DHT decreased expression of igfbp5b1. DHT and T decreased expression of myogenin, while other muscle regulatory factors were either not affected or responded similarly for all steroid treatments. Genes within the TGFβ superfamily signaling cascade responded to steroid treatment in both liver and muscle, suggesting a regulatory role for sex steroids in the ability to transmit signals initiated by TGFβ superfamily ligands, with a greater number of genes responding in liver than in muscle. Estrogen receptors were also regulated by sex steroids, with era1 expression increasing for all treatments in muscle, but only E2- and T-treatment in liver. E2 reduced expression of erb2 in liver. Collectively, these data identify how physiological mechanisms are regulated by sex steroids in a manner that promotes the disparate effects of androgens and estrogens on growth in salmonids. Published by Elsevier Inc.

Evidence supporting a role for TopBP1 and Brd4 in the initiation but not continuation of human papillomavirus 16 E1/E2-mediated DNA replication.

PubMed

Gauson, Elaine J; Donaldson, Mary M; Dornan, Edward S; Wang, Xu; Bristol, Molly; Bodily, Jason M; Morgan, Iain M

2015-05-01

To replicate the double-stranded human papillomavirus 16 (HPV16) DNA genome, viral proteins E1 and E2 associate with the viral origin of replication, and E2 can also regulate transcription from adjacent promoters. E2 interacts with host proteins in order to regulate both transcription and replication; TopBP1 and Brd4 are cellular proteins that interact with HPV16 E2. Previous work with E2 mutants demonstrated the Brd4 requirement for the transactivation properties of E2, while TopBP1 is required for DNA replication induced by E2 from the viral origin of replication in association with E1. More-recent studies have also implicated Brd4 in the regulation of DNA replication by E2 and E1. Here, we demonstrate that both TopBP1 and Brd4 are present at the viral origin of replication and that interaction with E2 is required for optimal initiation of DNA replication. Both cellular proteins are present in E1-E2-containing nuclear foci, and the viral origin of replication is required for the efficient formation of these foci. Short hairpin RNA (shRNA) against either TopBP1 or Brd4 destroys the E1-E2 nuclear bodies but has no effect on E1-E2-mediated levels of DNA replication. An E2 mutation in the context of the complete HPV16 genome that compromises Brd4 interaction fails to efficiently establish episomes in primary human keratinocytes. Overall, the results suggest that interactions between TopBP1 and E2 and between Brd4 and E2 are required to correctly initiate DNA replication but are not required for continuing DNA replication, which may be mediated by alternative processes such as rolling circle amplification and/or homologous recombination. Human papillomavirus 16 (HPV16) is causative in many human cancers, including cervical and head and neck cancers, and is responsible for the annual deaths of hundreds of thousands of people worldwide. The current vaccine will save lives in future generations, but antivirals targeting HPV16 are required for the alleviation of disease burden on the current, and future, generations. Targeting viral DNA replication that is mediated by two viral proteins, E1 and E2, in association with cellular proteins such as TopBP1 and Brd4 would have therapeutic benefits. This report suggests a role for these cellular proteins in the initiation of viral DNA replication by HPV16 E1-E2 but not for continuing replication. This is important if viral replication is to be effectively targeted; we need to understand the viral and cellular proteins required at each phase of viral DNA replication so that it can be effectively disrupted. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Evidence Supporting a Role for TopBP1 and Brd4 in the Initiation but Not Continuation of Human Papillomavirus 16 E1/E2-Mediated DNA Replication

PubMed Central

Gauson, Elaine J.; Donaldson, Mary M.; Dornan, Edward S.; Wang, Xu; Bristol, Molly; Bodily, Jason M.

2015-01-01

ABSTRACT To replicate the double-stranded human papillomavirus 16 (HPV16) DNA genome, viral proteins E1 and E2 associate with the viral origin of replication, and E2 can also regulate transcription from adjacent promoters. E2 interacts with host proteins in order to regulate both transcription and replication; TopBP1 and Brd4 are cellular proteins that interact with HPV16 E2. Previous work with E2 mutants demonstrated the Brd4 requirement for the transactivation properties of E2, while TopBP1 is required for DNA replication induced by E2 from the viral origin of replication in association with E1. More-recent studies have also implicated Brd4 in the regulation of DNA replication by E2 and E1. Here, we demonstrate that both TopBP1 and Brd4 are present at the viral origin of replication and that interaction with E2 is required for optimal initiation of DNA replication. Both cellular proteins are present in E1-E2-containing nuclear foci, and the viral origin of replication is required for the efficient formation of these foci. Short hairpin RNA (shRNA) against either TopBP1 or Brd4 destroys the E1-E2 nuclear bodies but has no effect on E1-E2-mediated levels of DNA replication. An E2 mutation in the context of the complete HPV16 genome that compromises Brd4 interaction fails to efficiently establish episomes in primary human keratinocytes. Overall, the results suggest that interactions between TopBP1 and E2 and between Brd4 and E2 are required to correctly initiate DNA replication but are not required for continuing DNA replication, which may be mediated by alternative processes such as rolling circle amplification and/or homologous recombination. IMPORTANCE Human papillomavirus 16 (HPV16) is causative in many human cancers, including cervical and head and neck cancers, and is responsible for the annual deaths of hundreds of thousands of people worldwide. The current vaccine will save lives in future generations, but antivirals targeting HPV16 are required for the alleviation of disease burden on the current, and future, generations. Targeting viral DNA replication that is mediated by two viral proteins, E1 and E2, in association with cellular proteins such as TopBP1 and Brd4 would have therapeutic benefits. This report suggests a role for these cellular proteins in the initiation of viral DNA replication by HPV16 E1-E2 but not for continuing replication. This is important if viral replication is to be effectively targeted; we need to understand the viral and cellular proteins required at each phase of viral DNA replication so that it can be effectively disrupted. PMID:25694599

Emerging Therapeutics Targeting mRNA Translation

PubMed Central

Malina, Abba; Mills, John R.; Pelletier, Jerry

2012-01-01

A defining feature of many cancers is deregulated translational control. Typically, this occurs at the level of recruitment of the 40S ribosomes to the 5′-cap of cellular messenger RNAs (mRNAs), the rate-limiting step of protein synthesis, which is controlled by the heterotrimeric eukaryotic initiation complex eIF4F. Thus, eIF4F in particular, and translation initiation in general, represent an exploitable vulnerability and unique opportunity for therapeutic intervention in many transformed cells. In this article, we discuss the development, mode of action and biological activity of a number of small-molecule inhibitors that interrupt PI3K/mTOR signaling control of eIF4F assembly, as well as compounds that more directly block eIF4F activity. PMID:22474009

Pregnancy-associated plasma protein-A (PAPP-A) levels in patients with severe allergic asthma are reduced by omalizumab.

PubMed

Bulut, Ismet; Ozseker, Zeynep F; Coskun, Abdurrahman; Serteser, Mustafa; Unsal, Ibrahim

2017-12-06

Remodeling is a crucial feature of severe asthma and may be associated with activation of the allergic cascade by immunoglobulin E (IgE). Omalizumab, an anti-IgE monoclonal antibody, effectively targets the severe allergic asthma phenotype. Pregnancy-associated plasma protein-A (PAPP-A) is an insulin-like growth factor binding protein-4 (IGFBP-4) protease, increasing local insulin-like growth factor (IGF)-1 concentrations, which in turn initiating a cascade involved in the regulation of cell growth, differentiation, and proliferation in various tissues. In the present study, we evaluated the effects of omalizumab on serum PAPP-A, IGFBP-4, and IGF-1 levels in subjects with severe allergic asthma. We studied 36 asthmatic subjects and 36 healthy controls. An ultrasensitive enzyme-linked immunosorbent assay (ELISA) kit was used to measure serum PAPP-A levels, and routine commercial ELISA kits were employed to assess serum levels of IGF-1, IGFBP-4 in control subjects and asthmatic subjects before therapy (baseline) and after six months of omalizumab therapy in patients with severe asthma. Compared to control subjects, serum PAPP-A and IGFB-4 levels were significantly higher in asthmatic subjects (both p values < 0.001). However, the serum IGF-I levels of asthmatic subjects were similar to those of control subjects (p > 0.05). In asthma subjects, 6-month omalizumab treatment significantly decreased the serum PAPP-A (p < 0.001), IGF-I (p = 0.031), and IGFB4 (p = 0.025) levels. PAPP-A level may be a useful biomarker for predicting airway remodeling in patients with severe asthma receiving omalizumab, and may also reflect the response to treatment.

Connective Tissue Growth Factor (CTGF) as a Regulator of Lactogenic Differentiation

DTIC Science & Technology

2009-06-09

1 1.62 Myeloid leukemia factor 1, Mlf1 1.57 ADAMTS-l4 1.55 E2F transcription factor, E2F2 1.44 Tensin 4 -1.5 BCL2/adenovirus E1B interacting... Mlf1 1.57 ADAMTS-l4 1.55 Ras homolog gene family, member B, RhoB 1.48 Cell Differentiation-associated Wingless-type MMTV integration site family...B, relB 1.92 Myeloid leukemia factor 1, Mlf1 1.57 Growth Factor, Catalytic Activity-associated Dual specificity protein phosphatase 8, Dusp8

The association of mammalian DREAM complex and HPV16 E7 proteins

PubMed Central

Rashid, Nurshamimi Nor; Rothan, Hussin A; Yusoff, Mohd Shahrizal Mohd

2015-01-01

The mammalian DREAM (Drosophila, RB, E2F, and Myb) complex was discovered in 2004 by several research groups. It was initially identified in Drosophila followed by Caenorhaditis elegans and later in mammalian cells. The composition of DREAM is temporally regulated during cell cycle; being associated with E2F-4 and either p107 or p130 in G0/G1 (repressive DREAM complexes) and with B-myb transcription factor in S/G2 (activator DREAM complex). High risk human papillomavirus (HPV) E6 and E7 oncoproteins expression are important for malignant transformation of cervical cancer cells. In particular, the E7 of high risk HPV binds to pRB family members (pRB, p107 and p130) for degradation. It has recently been discovered that the p107 and p130 ‘pocket proteins’ are members of mammalian DREAM complexes. With this understanding, we would like to hypothesise the mammalian DREAM complex could plays a critical role for malignant transformation in cervical cancer cells. PMID:26885443

An instrumental variable approach finds no associated harm or benefit from early dialysis initiation in the United States

PubMed Central

Scialla, Julia J.; Liu, Jiannong; Crews, Deidra C.; Guo, Haifeng; Bandeen-Roche, Karen; Ephraim, Patti L.; Tangri, Navdeep; Sozio, Stephen M.; Shafi, Tariq; Miskulin, Dana C.; Michels, Wieneke M.; Jaar, Bernard G.; Wu, Albert W.; Powe, Neil R.; Boulware, L. Ebony

2014-01-01

The estimated glomerular filtration rate (eGFR) at dialysis initiation has been rising. Observational studies suggest harm, but may be confounded by unmeasured factors. As instrumental variable methods may be less biased we performed a retrospective cohort study of 310,932 patients starting dialysis between 2006 to 2008 and registered in the United States Renal Data System in order to describe geographic variation in eGFR at dialysis initiation and determine its association with mortality. Patients were grouped into 804 health service areas by zip code. Individual eGFR at dialysis initiation averaged 10.8 ml/min/1.73m2 but varied geographically. Only 11% of the variation in mean health service areas-level eGFR at dialysis initiation was accounted for by patient characteristics. We calculated demographic-adjusted mean eGFR at dialysis initiation in the health service areas using the 2006 and 2007 incident cohort as our instrument and estimated the association between individual eGFR at dialysis initiation and mortality in the 2008 incident cohort using the 2 stage residual inclusion method. Among 89,547 patients starting dialysis in 2008 with eGFR 5 to 20 ml/min/1.73m2, eGFR at initiation was not associated with mortality over a median of 15.5 months [hazard ratio 1.025 per 1 ml/min/1.73m2 for eGFR 5 to 14 ml/min/1.73m2; and 0.973 per 1 ml/min/1.73m2 for eGFR 14 to 20 ml/min/1.73m2]. Thus, there was no associated harm or benefit from early dialysis initiation in the United States. PMID:24786707

Awareness and determinants of electronic cigarette use among Finnish adolescents in 2013: a population-based study

PubMed Central

Kinnunen, Jaana Maarit; Ollila, Hanna; El-Amin, Salma El-Tayeb; Pere, Lasse Antero; Lindfors, Pirjo Liisa; Rimpelä, Arja Hannele

2015-01-01

Background A wide range of electronic cigarettes (e-cigarettes) are now on the market. We studied e-cigarette awareness and use, determinants and sources of e-cigarettes, the e-liquids used in them and exposure to e-cigarette advertisements among adolescents in Finland. Among smokers, we studied the association of e-cigarette use and interest in smoking cessation. Method Data were obtained from a national survey of 12–18-year-old Finnish adolescents in 2013 (N=3535, response rate 38%). Descriptive statistics and logistic regression analysis were used. Results Of the respondents, 85.3% knew what e-cigarettes were; 17.4% had tried them. E-liquids with nicotine were used most often (65.7%); also those who had never tried conventional cigarettes had used them. Of e-cigarette ever users, 8.3% had never tried smoking. Parents’ high level of education, being in employment, and intact family protected against children's e-cigarette use. In the final model, daily smoking (OR 41.35; 95% CI 25.2 to 67.8), snus use (2.96; 2.4–4.0), waterpipe use (2.21; 1.6–3.0), children's vocational education (2.06; 1.4–3.1) and poor school performance (1.92; 1.4–3.0) were associated with e-cigarette experimentation. Those smokers with most experience of e-cigarettes were least likely to consider smoking cessation. Conclusions Awareness and experimentation with e-cigarettes are high among adolescents, especially in older age groups and boys. Nicotine e-liquids are easy to acquire for youth. Having similar risk factors, e-cigarette use seems to follow the model of conventional smoking initiation. Among adolescent smokers, use of e-cigarettes does not clearly relate to interest in smoking cessation. Preventive policies are needed to protect the youth. PMID:24827977

Awareness and determinants of electronic cigarette use among Finnish adolescents in 2013: a population-based study.

PubMed

Kinnunen, Jaana Maarit; Ollila, Hanna; El-Amin, Salma El-Tayeb; Pere, Lasse Antero; Lindfors, Pirjo Liisa; Rimpelä, Arja Hannele

2015-12-01

A wide range of electronic cigarettes (e-cigarettes) are now on the market. We studied e-cigarette awareness and use, determinants and sources of e-cigarettes, the e-liquids used in them and exposure to e-cigarette advertisements among adolescents in Finland. Among smokers, we studied the association of e-cigarette use and interest in smoking cessation. Data were obtained from a national survey of 12-18-year-old Finnish adolescents in 2013 (N=3535, response rate 38%). Descriptive statistics and logistic regression analysis were used. Of the respondents, 85.3% knew what e-cigarettes were; 17.4% had tried them. E-liquids with nicotine were used most often (65.7%); also those who had never tried conventional cigarettes had used them. Of e-cigarette ever users, 8.3% had never tried smoking. Parents' high level of education, being in employment, and intact family protected against children's e-cigarette use. In the final model, daily smoking (OR 41.35; 95% CI 25.2 to 67.8), snus use (2.96; 2.4-4.0), waterpipe use (2.21; 1.6-3.0), children's vocational education (2.06; 1.4-3.1) and poor school performance (1.92; 1.4-3.0) were associated with e-cigarette experimentation. Those smokers with most experience of e-cigarettes were least likely to consider smoking cessation. Awareness and experimentation with e-cigarettes are high among adolescents, especially in older age groups and boys. Nicotine e-liquids are easy to acquire for youth. Having similar risk factors, e-cigarette use seems to follow the model of conventional smoking initiation. Among adolescent smokers, use of e-cigarettes does not clearly relate to interest in smoking cessation. Preventive policies are needed to protect the youth. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Usefulness of circulating E-selectin to early detection of the atherosclerotic process in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

PubMed

de Almeida-Pititto, Bianca; Ribeiro-Filho, Fernando Flexa; Bittencourt, Marcio Sommer; Lotufo, Paulo A; Bensenor, Isabela; Ferreira, Sandra R G

2016-01-01

This cross-sectional analysis evaluated whether determination of E-selectin concentrations could identify deterioration of cardiometabolic risk profile or subclinical atherosclerosis in individuals at low-to-moderate risk included in The Brazilian Longitudinal Study of Adult Health-ELSA-Brasil. A sample of 984 individuals from ELSA-Brasil (35-54 years) without cardiovascular disease or diabetes was stratified according to E-selectin tertiles. Traditional risk factors, inflammatory markers and categories of coronary artery calcium (CAC) scores were evaluated across the tertiles by ANOVA or Chi-squared test. In linear regression models, associations of E-selectin levels with insulin resistance index, adjusted for age, sex and adiposity were tested. The mean age of the participants was 45.8 (SD 4.9) years and 55 % were women. Mean values of age, anthropometric data, biochemical variables and inflammatory status increased across E-selectin tertiles. Also, a gradual deterioration of the cardiometabolic profile was reflected by increments in frequencies (95 % CI) of BMI ≥ 25 kg/m(2) [53.7 % (48.5-58.8), 61.0 % (56.1-66.5) and 64.2 % (59.0-69.4), p = 0.019], hypertension [18.0 % (14.1-22.8), 19.8 % (15.4-24.6) and 24.8 % (20.4-29.9), p = 0.048], pre-diabetes [62.5 % (57.4-68.3), 63.1 % (58.4-69.6) and 73.8 % (68.8-78.3), p = 0.003] and hypertriglyceridemia [22.4 % (17.9-27.2), 27.3 % (22.5-32.8) and 33.4 % (28.3-38.5), p = 0.013]. Insulinemia and HOMA-IR were independently associated with E-selectin concentration. A greater proportion of individuals with CAC scores different from zero was found in the third tertile when compared with the first and second tertiles (16.1 versus 11 %, p = 0.04, respectively). Direct associations of E-selectin with traditional risk factors slightly above their normal ranges, components of the metabolic syndrome, insulin resistance and presence of CAC suggest that this biomarker may indicate an initial atherogenic process.

Chronic copper exposure causes spatial memory impairment, selective loss of hippocampal synaptic proteins, and activation of PKR/eIF2α pathway in mice.

PubMed

Ma, Quan; Ying, Ming; Sui, Xiaojing; Zhang, Huimin; Huang, Haiyan; Yang, Linqing; Huang, Xinfeng; Zhuang, Zhixiong; Liu, Jianjun; Yang, Xifei

2015-01-01

Copper is an essential element for human growth and development; however, excessive intake of copper could contribute to neurotoxicity. Here we show that chronic exposure to copper in drinking water impaired spatial memory with simultaneous selective loss of hippocampal pre-synaptic protein synapsin 1, and post-synaptic density protein (PSD)-93/95 in mice. Copper exposure was shown to elevate the levels of nitrotyrosine and 8-hydroxydeoxyguanosine (8-OHdG) in hippocampus, two markers of oxidative stress. Concurrently, we also found that copper exposure activated double stranded RNA-dependent protein kinase (PKR) as evidenced by increased ratio of phosphorylated PKR at Thr451 and total PKR and increased the phosphorylation of its downstream signaling molecule eukaryotic initiation factor 2α (eIF2α) at Ser51 in hippocampus. Consistent with activation of PKR/eIF2α signaling pathway which was shown to mediate synaptic deficit and cognitive impairment, the levels of activating transcription factor 4 (ATF-4), a downstream signaling molecule of eIF2α and a repressor of CREB-mediated gene expression, were significantly increased, while the activity of cAMP response elements binding protein (CREB) was inactivated as suggested by decreased phosphorylation of CREB at Ser133 by copper exposure. In addition, the expression of the pro-apoptotic target molecule C/EBP homology protein (CHOP) of ATF-4 was upregulated and hippocampal neuronal apoptosis was induced by copper exposure. Taken together, we propose that chronic copper exposure might cause spatial memory impairment, selective loss of synaptic proteins, and neuronal apoptosis through the mechanisms involving activation of PKR/eIF2α signaling pathway.

Crimean-Congo Hemorrhagic Fever Virus Nucleocapsid Protein Augments mRNA Translation.

PubMed

Jeeva, Subbiah; Cheng, Erdong; Ganaie, Safder S; Mir, Mohammad A

2017-08-01

Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne Nairovirus of the Bunyaviridae family, causing severe illness with high mortality rates in humans. Here, we demonstrate that CCHFV nucleocapsid protein (CCHFV-NP) augments mRNA translation. CCHFV-NP binds to the viral mRNA 5' untranslated region (UTR) with high affinity. It facilitates the translation of reporter mRNA both in vivo and in vitro with the assistance of the viral mRNA 5' UTR. CCHFV-NP equally favors the translation of both capped and uncapped mRNAs, demonstrating the independence of this translation strategy on the 5' cap. Unlike the canonical host translation machinery, inhibition of eIF4F complex, an amalgam of three initiation factors, eIF4A, eIF4G, and eIF4E, by the chemical inhibitor 4E1RCat did not impact the CCHFV-NP-mediated translation mechanism. However, the proteolytic degradation of eIF4G alone by the human rhinovirus 2A protease abrogated this translation strategy. Our results demonstrate that eIF4F complex formation is not required but eIF4G plays a critical role in this translation mechanism. Our results suggest that CCHFV has adopted a unique translation mechanism to facilitate the translation of viral mRNAs in the host cell cytoplasm where cellular transcripts are competing for the same translation apparatus. IMPORTANCE Crimean-Congo hemorrhagic fever, a highly contagious viral disease endemic to more than 30 countries, has limited treatment options. Our results demonstrate that NP favors the translation of a reporter mRNA harboring the viral mRNA 5' UTR. It is highly likely that CCHFV uses an NP-mediated translation strategy for the rapid synthesis of viral proteins during the course of infection. Shutdown of this translation mechanism might selectively impact viral protein synthesis, suggesting that an NP-mediated translation strategy is a target for therapeutic intervention against this viral disease. Copyright © 2017 American Society for Microbiology.

Factors associated with psychoactive drug initiation in a sample of workers in France: results of the VISAT cohort study.

PubMed

Boeuf-Cazou, O; Niezborala, M; Marquie, J C; Lapeyre-Mestre, M

2010-03-01

To identify which psychosocial factors at work are associated with the initiation of psychoactive drug use in a cohort of healthy French workers. This study used data collected from the VISAT ('Vieillissement, Santé, Travail') cohort which included workers aged 32, 42, 52 and 62 years in 1996 with follow-ups conducted over the following 5 years. Data were collected through interviews and five standardized questionnaires in annual occupational medical examinations in 1996, 1999 and 2001. We defined new consumers of psychoactive drugs according to their answers during the follow-ups and compared their psychosocial and working characteristics to non-consumers. A multivariate logistic regression analysis was performed to investigate factors related to a psychoactive drug initiation. Among 1533 subjects, 5.4% began consuming psychoactive drugs during the follow-up with a twofold rate for women than for men. Factors related to psychoactive drug initiation were different according to gender. In men, initiation was mainly found in participants who were separated, showed high emotional reaction scores and were members of the white-collar working class. We did not find any other occupational factors associated to psychoactive drug initiation in men. By contrast, among women, drug initiation was more frequent in participants who were 52 years old and over, and whose job control-reward level was lower. Psychoactive drug initiation concerned 5.4% of workers within the 5-year interval in this study. The pressure of psychosocial environment was more important in men, whereas age and work-related psychosocial factors were the main factors associated with new consumption among women.

Improved survival in HIV treatment programs in Asia

PubMed Central

De La Mata, Nicole L; Kumarasamy, Nagalingeswaran; Khol, Vohith; Ng, Oon Tek; Van Nguyen, Kinh; Merati, Tuti Parwati; Pham, Thuy Thanh; Lee, Man Po; Durier, Nicolas; Law, Matthew

2016-01-01

Background Antiretroviral treatment (ART) for HIV-positive patients has expanded rapidly in Asia over the last ten years. Our study aimed to describe the time trends and risk factors for overall survival in patients receiving first-line ART in Asia. Methods We included HIV-positive adult patients who initiated ART between 2003–2013 (n=16 546), from seven sites across six Asia-Pacific countries. Patient follow-up was to May 2014. We compared survival for each country and overall by time period of ART initiation using Kaplan-Meier curves. Factors associated with mortality were assessed using Cox regression, stratified by site. We also summarized first-line ART regimens, CD4 count at ART initiation, and CD4 and HIV viral load testing frequencies. Results There were 880 deaths observed over 54 532 person-years of follow-up, a crude rate of 1.61 (1.51, 1.72) per 100 person-years. Survival significantly improved in more recent years of ART initiation. The survival probabilities at 4 years follow-up for those initiating ART in 2003–05 was 92.1%, 2006–09 was 94.3% and 2010–2013 was 94.5% (p<0.001). Factors associated with higher mortality risk included initiating ART in earlier time periods, older age, male sex, injecting drug use as HIV exposure and lower pre-ART CD4 count. Concurrent with improved survival was increased tenofovir use, ART initiation at higher CD4 counts, and greater monitoring of CD4 and HIV viral load. Conclusions Our results suggest that HIV-positive patients from Asia have improved survival in more recent years of ART initiation. This is likely a consequence of improvements in treatment and, patient management and monitoring over time. PMID:26961354

How does a scanning ribosomal particle move along the 5'-untranslated region of eukaryotic mRNA? Brownian Ratchet model.

PubMed

Spirin, Alexander S

2009-11-17

A model of the ATP-dependent unidirectional movement of the 43S ribosomal initiation complex (=40S ribosomal subunit + eIF1 + eIF1A + eIF2.GTP.Met-tRNA(i) + eIF3) during scanning of the 5'-untranslated region of eukaryotic mRNA is proposed. The model is based on the principles of molecular Brownian ratchet machines and explains several enigmatic data concerning the scanning complex. In this model, the one-dimensional diffusion of the ribosomal initiation complex along the mRNA chain is rectified into the net-unidirectional 5'-to-3' movement by the Feynman ratchet-and-pawl mechanism. The proposed mechanism is organized by the heterotrimeric protein eIF4F (=eIF4A + eIF4E + eIF4G), attached to the scanning ribosomal particle via eIF3, and the RNA-binding protein eIF4B that is postulated to play the role of the pawl. The energy for the useful work of the ratchet-and-pawl mechanism is supplied from ATP hydrolysis induced by the eIF4A subunit: ATP binding and its hydrolysis alternately change the affinities of eIF4A for eIF4B and for mRNA, resulting in the restriction of backward diffusional sliding of the 43S ribosomal complex along the mRNA chain, while stochastic movements ahead are allowed.

NIa-Pro of Papaya ringspot virus interacts with Carica papaya eukaryotic translation initiation factor 3 subunit G (CpeIF3G).

PubMed

Gao, Le; Tuo, Decai; Shen, Wentao; Yan, Pu; Li, Xiaoying; Zhou, Peng

2015-02-01

The interaction of papaya eukaryotic translation initiation factor 3 subunit G (CpeIF3G) with Papaya ringspot virus (PRSV) NIa-Pro was validated using a bimolecular fluorescence complementation assay in papaya protoplasts based on the previous yeast two-hybrid assay results. The C-terminal (residues 133-239) fragment of PRSV NIa-Pro and the central domain (residues 59-167) of CpeIF3G were required for effective interaction between NIa-Pro and CpeIF3G as shown by a Sos recruitment yeast two-hybrid system with several deletion mutants of NIa-Pro and CpeIF3G. The central domain of CpeIF3G, which contains a C2HC-type zinc finger motif, is required to bind to other eIFs of the translational machinery. In addition, quantitative real-time reverse transcription PCR assay confirmed that PRSV infection leads to a 2- to 4.5-fold up-regulation of CpeIF3G mRNA in papaya. Plant eIF3G is involved in various stress response by enhancing the translation of resistance-related proteins. It is proposed that the NIa-Pro-CpeIF3G interaction may impair translation preinitiation complex assembly of defense proteins and interfere with host defense.

[Degradation of Organic Sunscreens 2-hydroxy-4-methoxybenzophenone by UV/ H2O2 Process: Kinetics and Factors].

PubMed

Feng, Xin-xin; Du, Er-deng; Guo, Ying-qing; Li, Hua-jie; Liu, Xiang; Zhou, Fang

2015-06-01

Organic sunscreens continue to enter the environment through people's daily consumption, and become a kind of emerging contaminants. The photochemical degradation of benzophenone-3 (BP-3) in water by UV/H2O2 process was investigated. Several factors, including the initial BP-3 concentration, H2O2 concentration, UV light intensity, coexisting cations and anions, humic acid and tert-butyl alcohol, were also discussed. The results showed that BP-3 degradation rate constant decreased with increasing initial BP-3 concentration, while increased with increasing H2O2 dosage and UV intensity. Coexisting anions could reduce the degradation rate, while coexisting ferric ions could stimulate the production of OH through Fenton-like reaction, further significantly accelerated BP-3 degradation process. The BP-3 degradation would be inhibited by humic acid or tert-butyl alcohol. The electrical energy per order (E(Eo)) values were also calculated to evaluate the cost of BP-3 degradation by UV/H2O2 process. The addition of ferric ions significantly reduced the value of E(Eo). The investigation of processing parameter could provide a reference for the practical engineering applications of benzophenone compounds removal by UV/H2O2 process.

Molecular Validation of PACE4 as a Target in Prostate Cancer12

PubMed Central

D'Anjou, François; Routhier, Sophie; Perreault, Jean-Pierre; Latil, Alain; Bonnel, David; Fournier, Isabelle; Salzet, Michel; Day, Robert

2011-01-01

Prostate cancer remains the single most prevalent cancer in men. Standard therapies are still limited and include androgen ablation that initially causes tumor regression. However, tumor cells eventually relapse and develop into a hormone-refractory prostate cancer. One of the current challenges in this disease is to define new therapeutic targets, which have been virtually unchanged in the past 30 years. Recent studies have suggested that the family of enzymes known as the proprotein convertases (PCs) is involved in various types of cancers and their progression. The present study examined PC expression in prostate cancer and validates one PC, namely PACE4, as a target. The evidence includes the observed high expression of PACE4 in all different clinical stages of human prostate tumor tissues. Gene silencing studies targeting PACE4 in the DU145 prostate cancer cell line produced cells (cell line 4-2) with slower proliferation rates, reduced clonogenic activity, and inability to grow as xenografts in nude mice. Gene expression and proteomic profiling of the 4-2 cell line reveals an increased expression of known cancer-related genes (e.g., GJA1, CD44, IGFBP6) that are downregulated in prostate cancer. Similarly, cancer genes whose expression is decreased in the 4-2 cell line were upregulated in prostate cancer (e.g., MUC1, IL6). The direct role of PACE4 in prostate cancer is most likely through the upregulated processing of growth factors or through the aberrant processing of growth factors leading to sustained cancer progression, suggesting that PACE4 holds a central role in prostate cancer. PMID:21633671

Conserved Sequences at the Origin of Adenovirus DNA Replication

PubMed Central

Stillman, Bruce W.; Topp, William C.; Engler, Jeffrey A.

1982-01-01

The origin of adenovirus DNA replication lies within an inverted sequence repetition at either end of the linear, double-stranded viral DNA. Initiation of DNA replication is primed by a deoxynucleoside that is covalently linked to a protein, which remains bound to the newly synthesized DNA. We demonstrate that virion-derived DNA-protein complexes from five human adenovirus serological subgroups (A to E) can act as a template for both the initiation and the elongation of DNA replication in vitro, using nuclear extracts from adenovirus type 2 (Ad2)-infected HeLa cells. The heterologous template DNA-protein complexes were not as active as the homologous Ad2 DNA, most probably due to inefficient initiation by Ad2 replication factors. In an attempt to identify common features which may permit this replication, we have also sequenced the inverted terminal repeated DNA from human adenovirus serotypes Ad4 (group E), Ad9 and Ad10 (group D), and Ad31 (group A), and we have compared these to previously determined sequences from Ad2 and Ad5 (group C), Ad7 (group B), and Ad12 and Ad18 (group A) DNA. In all cases, the sequence around the origin of DNA replication can be divided into two structural domains: a proximal A · T-rich region which is partially conserved among these serotypes, and a distal G · C-rich region which is less well conserved. The G · C-rich region contains sequences similar to sequences present in papovavirus replication origins. The two domains may reflect a dual mechanism for initiation of DNA replication: adenovirus-specific protein priming of replication, and subsequent utilization of this primer by host replication factors for completion of DNA synthesis. Images PMID:7143575

Degradation of 2,4-dichlorophenol with a novel TiO2/Ti-Fe-graphite felt photoelectrocatalytic oxidation process.

PubMed

Zhao, Bao-xiu; Li, Xiang-zhong; Wang, Peng

2007-01-01

Degradation of 2,4-dichlorophenol (2,4-DCP) was studied in a novel three-electrode photoelectrocatalytic (PEC) integrative oxidation process, and the factors influencing the degradation rate, such as applied current, flow speed of O2, pH, adscititious voltage and initial 2,4-DCP concentration were investigated and optimized. H2O2 was produced nearby cathode and Fe2+ continuously generated from Fe anode in solution when current and O2 were applied, so, main reactions, H2O2-assisted TiO2 PEC oxidation and E-Fenton reaction, occurred during degradation of 2,4-DCP in this integrative system. The degradation ratio of 2,4-DCP was 93% in this integrative oxidation process, while it was only 31% in E-Fenton process and 46% in H2O2-assisted TiO2 PEC process. So, it revealed that the degradation of 2,4-DCP was improved greatly by photoelectrical cooperation effect. By the investigation of pH, it showed that this integrative process could work well in a wide pH range from pH 3 to pH 9.

Human Merkel cell polyomavirus small T antigen is an oncoprotein targeting the 4E-BP1 translation regulator

PubMed Central

Shuda, Masahiro; Kwun, Hyun Jin; Feng, Huichen; Chang, Yuan; Moore, Patrick S.

2011-01-01

Merkel cell polyomavirus (MCV) is the recently discovered cause of most Merkel cell carcinomas (MCCs), an aggressive form of nonmelanoma skin cancer. Although MCV is known to integrate into the tumor cell genome and to undergo mutation, the molecular mechanisms used by this virus to cause cancer are unknown. Here, we show that MCV small T (sT) antigen is expressed in most MCC tumors, where it is required for tumor cell growth. Unlike the closely related SV40 sT, MCV sT transformed rodent fibroblasts to anchorage- and contact-independent growth and promoted serum-free proliferation of human cells. These effects did not involve protein phosphatase 2A (PP2A) inhibition. MCV sT was found to act downstream in the mammalian target of rapamycin (mTOR) signaling pathway to preserve eukaryotic translation initiation factor 4E–binding protein 1 (4E-BP1) hyperphosphorylation, resulting in dysregulated cap-dependent translation. MCV sT–associated 4E-BP1 serine 65 hyperphosphorylation was resistant to mTOR complex (mTORC1) and mTORC2 inhibitors. Steady-state phosphorylation of other downstream Akt-mTOR targets, including S6K and 4E-BP2, was also increased by MCV sT. Expression of a constitutively active 4E-BP1 that could not be phosphorylated antagonized the cell transformation activity of MCV sT. Taken together, these experiments showed that 4E-BP1 inhibition is required for MCV transformation. Thus, MCV sT is an oncoprotein, and its effects on dysregulated cap-dependent translation have clinical implications for the prevention, diagnosis, and treatment of MCV-related cancers. PMID:21841310

Replication Validity of Initial Association Studies: A Comparison between Psychiatry, Neurology and Four Somatic Diseases.

PubMed

Dumas-Mallet, Estelle; Button, Katherine; Boraud, Thomas; Munafo, Marcus; Gonon, François

2016-01-01

There are growing concerns about effect size inflation and replication validity of association studies, but few observational investigations have explored the extent of these problems. Using meta-analyses to measure the reliability of initial studies and explore whether this varies across biomedical domains and study types (cognitive/behavioral, brain imaging, genetic and "others"). We analyzed 663 meta-analyses describing associations between markers or risk factors and 12 pathologies within three biomedical domains (psychiatry, neurology and four somatic diseases). We collected the effect size, sample size, publication year and Impact Factor of initial studies, largest studies (i.e., with the largest sample size) and the corresponding meta-analyses. Initial studies were considered as replicated if they were in nominal agreement with meta-analyses and if their effect size inflation was below 100%. Nominal agreement between initial studies and meta-analyses regarding the presence of a significant effect was not better than chance in psychiatry, whereas it was somewhat better in neurology and somatic diseases. Whereas effect sizes reported by largest studies and meta-analyses were similar, most of those reported by initial studies were inflated. Among the 256 initial studies reporting a significant effect (p<0.05) and paired with significant meta-analyses, 97 effect sizes were inflated by more than 100%. Nominal agreement and effect size inflation varied with the biomedical domain and study type. Indeed, the replication rate of initial studies reporting a significant effect ranged from 6.3% for genetic studies in psychiatry to 86.4% for cognitive/behavioral studies. Comparison between eight subgroups shows that replication rate decreases with sample size and "true" effect size. We observed no evidence of association between replication rate and publication year or Impact Factor. The differences in reliability between biological psychiatry, neurology and somatic diseases suggest that there is room for improvement, at least in some subdomains.

Replication Validity of Initial Association Studies: A Comparison between Psychiatry, Neurology and Four Somatic Diseases

PubMed Central

Dumas-Mallet, Estelle; Button, Katherine; Boraud, Thomas; Munafo, Marcus; Gonon, François

2016-01-01

Context There are growing concerns about effect size inflation and replication validity of association studies, but few observational investigations have explored the extent of these problems. Objective Using meta-analyses to measure the reliability of initial studies and explore whether this varies across biomedical domains and study types (cognitive/behavioral, brain imaging, genetic and “others”). Methods We analyzed 663 meta-analyses describing associations between markers or risk factors and 12 pathologies within three biomedical domains (psychiatry, neurology and four somatic diseases). We collected the effect size, sample size, publication year and Impact Factor of initial studies, largest studies (i.e., with the largest sample size) and the corresponding meta-analyses. Initial studies were considered as replicated if they were in nominal agreement with meta-analyses and if their effect size inflation was below 100%. Results Nominal agreement between initial studies and meta-analyses regarding the presence of a significant effect was not better than chance in psychiatry, whereas it was somewhat better in neurology and somatic diseases. Whereas effect sizes reported by largest studies and meta-analyses were similar, most of those reported by initial studies were inflated. Among the 256 initial studies reporting a significant effect (p<0.05) and paired with significant meta-analyses, 97 effect sizes were inflated by more than 100%. Nominal agreement and effect size inflation varied with the biomedical domain and study type. Indeed, the replication rate of initial studies reporting a significant effect ranged from 6.3% for genetic studies in psychiatry to 86.4% for cognitive/behavioral studies. Comparison between eight subgroups shows that replication rate decreases with sample size and “true” effect size. We observed no evidence of association between replication rate and publication year or Impact Factor. Conclusion The differences in reliability between biological psychiatry, neurology and somatic diseases suggest that there is room for improvement, at least in some subdomains. PMID:27336301

Increased expression of phosphorylated forms of RNA-dependent protein kinase and eukaryotic initiation factor 2α may signal skeletal muscle atrophy in weight-losing cancer patients

PubMed Central

Eley, H L; Skipworth, R J E; Deans, D A C; Fearon, K C H; Tisdale, M J

2007-01-01

Previous studies suggest that the activation (autophosphorylation) of dsRNA-dependent protein kinase (PKR) can stimulate protein degradation, and depress protein synthesis in skeletal muscle through phosphorylation of the translation initiation factor 2 (eIF2) on the α-subunit. To understand whether these mediators are important in muscle wasting in cancer patients, levels of the phospho forms of PKR and eIF2α have been determined in rectus abdominus muscle of weight losing patients with oesophago-gastric cancer, in comparison with healthy controls. Levels of both phospho PKR and phospho eIF2α were significantly enhanced in muscle of cancer patients with weight loss irrespective of the amount and there was a linear relationship between phosphorylation of PKR and phosphorylation of eIF2α (correlation coefficient 0.76, P=0.005). This suggests that phosphorylation of PKR led to phosphorylation of eIF2α. Myosin levels decreased as the weight loss increased, and there was a linear relationship between myosin expression and the extent of phosphorylation of eIF2α (correlation coefficient 0.77, P=0.004). These results suggest that phosphorylation of PKR may be an important initiator of muscle wasting in cancer patients. PMID:18087277

Wnt4 is essential to normal mammalian lung development.

PubMed

Caprioli, Arianna; Villasenor, Alethia; Wylie, Lyndsay A; Braitsch, Caitlin; Marty-Santos, Leilani; Barry, David; Karner, Courtney M; Fu, Stephen; Meadows, Stryder M; Carroll, Thomas J; Cleaver, Ondine

2015-10-15

Wnt signaling is essential to many events during organogenesis, including the development of the mammalian lung. The Wnt family member Wnt4 has been shown to be required for the development of kidney, gonads, thymus, mammary and pituitary glands. Here, we show that Wnt4 is critical for proper morphogenesis and growth of the respiratory system. Using in situ hybridization in mouse embryos, we identify a previously uncharacterized site of Wnt4 expression in the anterior trunk mesoderm. This expression domain initiates as early as E8.25 in the mesoderm abutting the tracheoesophageal endoderm, between the fusing dorsal aortae and the heart. Analysis of Wnt4(-/-) embryos reveals severe lung hypoplasia and tracheal abnormalities; however, aortic fusion and esophageal development are unaffected. We find decreased cell proliferation in Wnt4(-/-) lung buds, particularly in tip domains. In addition, we observe reduction of the important lung growth factors Fgf9, Fgf10, Sox9 and Wnt2 in the lung bud during early stages of organogenesis, as well as decreased tracheal expression of the progenitor factor Sox9. Together, these data reveal a previously unknown role for the secreted protein Wnt4 in respiratory system development. Copyright © 2015. Published by Elsevier Inc.

Military Health Service System Ambulatory Work Unit (AWU).

DTIC Science & Technology

1988-04-01

E-40 BBC-4 Ambulatory Work Unit Distribution Screen Passes BBC - Neurosurgery Clinic .... ............. . E-40 BBD -I Initial Record...Screen Failures BBD - Ophthalmology Clinic ... ............ E-41 BBD -2 Distribution Screen Failures BBD - Ophthalmology Clinic ............ E-41 BBD -3...Descriptive Statistics Distribution Screen Passes BBD - Ophthalmology Clinic ............ E-42 BBD -4 Ambulatory Work Unit Distribution Screen Passes BBD

Fission yeast translation initiation factor 3 subunit eIF3h is not essential for global translation initiation, but deletion of eif3h+ affects spore formation.

PubMed

Ray, Anirban; Bandyopadhyay, Amitabha; Matsumoto, Tomohiro; Deng, Haiteng; Maitra, Umadas

2008-11-01

The fission yeast Schizosaccharomyces pombe homologue of the p40/eIF3h subunit of mammalian translation initiation factor eIF3 has been characterized in this study. We show that this protein physically associates with the 40S ribosomal particles as a constituent of the multimeric eIF3 protein complex, which consists of all five known eIF3 core subunits (eIF3a, eIF3b, eIF3c, eIF3g and eIF3i) as well as the five non-core subunits (eIF3d, eIF3e, eIF3f, eIF3h and eIF3m) that constitute an eIF3 holocomplex in fission yeast. However, affinity purification of eIF3 from fission yeast cells expressing TAP-tagged eIF3h suggests the presence of distinct forms of eIF3 that differ in their composition of the non-core subunits. Further characterization of eIF3h shows that strains lacking eif3h(+) (eif3hDelta) are viable and show no gross defects, either in vegetative growth or in the rate of in vivo protein synthesis. Polysome profile analysis shows no apparent defects in translation initiation. Furthermore, deletion of eif3h(+) does not affect the ability of the other eIF3 subunits to remain associated with one another in a tight protein complex similar to the situation in wild-type cells. Additionally, we show that human eIF3h can functionally substitute fission yeast eIF3h in complementing in vivo a genetic deletion of eif3h(+). Interestingly, mutant eif3hDelta cells show several prominent phenotypic properties. They are hypersensitive to caffeine and highly defective in meiosis, producing either no spores or incomplete tetrads with a very high frequency. The implications of these results in relation to the functions of eIF3h in Sz. pombe are discussed. (c) 2008 John Wiley & Sons, Ltd.

Anti-Tumor Effects of Ganoderma lucidum (Reishi) in Inflammatory Breast Cancer in In Vivo and In Vitro Models

PubMed Central

Suarez-Arroyo, Ivette J.; Rosario-Acevedo, Raysa; Aguilar-Perez, Alexandra; Clemente, Pedro L.; Cubano, Luis A.; Serrano, Juan; Schneider, Robert J.; Martínez-Montemayor, Michelle M.

2013-01-01

The medicinal mushroom Ganoderma lucidum (Reishi) was tested as a potential therapeutic for Inflammatory Breast Cancer (IBC) using in vivo and in vitro IBC models. IBC is a lethal and aggressive form of breast cancer that manifests itself without a typical tumor mass. Studies show that IBC tissue biopsies overexpress E-cadherin and the eukaryotic initiation factor 4GI (eIF4GI), two proteins that are partially responsible for the unique pathological properties of this disease. IBC is treated with a multimodal approach that includes non-targeted systemic chemotherapy, surgery, and radiation. Because of its non-toxic and selective anti-cancer activity, medicinal mushroom extracts have received attention for their use in cancer therapy. Our previous studies demonstrate these selective anti-cancer effects of Reishi, where IBC cell viability and invasion, as well as the expression of key IBC molecules, including eIF4G is compromised. Thus, herein we define the mechanistic effects of Reishi focusing on the phosphoinositide-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway, a regulator of cell survival and growth. The present study demonstrates that Reishi treated IBC SUM-149 cells have reduced expression of mTOR downstream effectors at early treatment times, as we observe reduced eIF4G levels coupled with increased levels of eIF4E bound to 4E-BP, with consequential protein synthesis reduction. Severe combined immunodeficient mice injected with IBC cells treated with Reishi for 13 weeks show reduced tumor growth and weight by ∼50%, and Reishi treated tumors showed reduced expression of E-cadherin, mTOR, eIF4G, and p70S6K, and activity of extracellular regulated kinase (ERK1/2). Our results provide evidence that Reishi suppresses protein synthesis and tumor growth by affecting survival and proliferative signaling pathways that act on translation, suggesting that Reishi is a potential natural therapeutic for breast and other cancers. PMID:23468988

Anti-tumor effects of Ganoderma lucidum (reishi) in inflammatory breast cancer in in vivo and in vitro models.

PubMed

Suarez-Arroyo, Ivette J; Rosario-Acevedo, Raysa; Aguilar-Perez, Alexandra; Clemente, Pedro L; Cubano, Luis A; Serrano, Juan; Schneider, Robert J; Martínez-Montemayor, Michelle M

2013-01-01

The medicinal mushroom Ganoderma lucidum (Reishi) was tested as a potential therapeutic for Inflammatory Breast Cancer (IBC) using in vivo and in vitro IBC models. IBC is a lethal and aggressive form of breast cancer that manifests itself without a typical tumor mass. Studies show that IBC tissue biopsies overexpress E-cadherin and the eukaryotic initiation factor 4GI (eIF4GI), two proteins that are partially responsible for the unique pathological properties of this disease. IBC is treated with a multimodal approach that includes non-targeted systemic chemotherapy, surgery, and radiation. Because of its non-toxic and selective anti-cancer activity, medicinal mushroom extracts have received attention for their use in cancer therapy. Our previous studies demonstrate these selective anti-cancer effects of Reishi, where IBC cell viability and invasion, as well as the expression of key IBC molecules, including eIF4G is compromised. Thus, herein we define the mechanistic effects of Reishi focusing on the phosphoinositide-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway, a regulator of cell survival and growth. The present study demonstrates that Reishi treated IBC SUM-149 cells have reduced expression of mTOR downstream effectors at early treatment times, as we observe reduced eIF4G levels coupled with increased levels of eIF4E bound to 4E-BP, with consequential protein synthesis reduction. Severe combined immunodeficient mice injected with IBC cells treated with Reishi for 13 weeks show reduced tumor growth and weight by ∼50%, and Reishi treated tumors showed reduced expression of E-cadherin, mTOR, eIF4G, and p70S6K, and activity of extracellular regulated kinase (ERK1/2). Our results provide evidence that Reishi suppresses protein synthesis and tumor growth by affecting survival and proliferative signaling pathways that act on translation, suggesting that Reishi is a potential natural therapeutic for breast and other cancers.

Density functional theory study of HfCl4, ZrCl4, and Al(CH3)3 decomposition on hydroxylated SiO2: Initial stage of high-k atomic layer deposition

NASA Astrophysics Data System (ADS)

Jeloaica, L.; Estève, A.; Djafari Rouhani, M.; Estève, D.

2003-07-01

The initial stage of atomic layer deposition of HfO2, ZrO2, and Al2O3 high-k films, i.e., the decomposition of HfCl4, ZrCl4, and Al(CH3)3 precursor molecules on an OH-terminated SiO2 surface, is investigated within density functional theory. The energy barriers are determined using artificial activation of vibrational normal modes. For all precursors, reaction proceeds through the formation of intermediate complexes that have equivalent formation energies (˜-0.45 eV), and results in HCl and CH4 formation with activation energies of 0.88, 0.91, and 1.04 eV for Hf, Zr, and Al based precursors, respectively. The reaction product of Al(CH3)3 decomposition is found to be more stable (by -1.45 eV) than the chemisorbed intermediate complex compared to the endothermic decomposition of HfCl4 and ZrCl4 chemisorbed precursors (0.26 and 0.29 eV, respectively).

Association of Electronic Cigarette Use With Initiation of Combustible Tobacco Product Smoking in Early Adolescence.

PubMed

Leventhal, Adam M; Strong, David R; Kirkpatrick, Matthew G; Unger, Jennifer B; Sussman, Steve; Riggs, Nathaniel R; Stone, Matthew D; Khoddam, Rubin; Samet, Jonathan M; Audrain-McGovern, Janet

2015-08-18

Exposure to nicotine in electronic cigarettes (e-cigarettes) is becoming increasingly common among adolescents who report never having smoked combustible tobacco. To evaluate whether e-cigarette use among 14-year-old adolescents who have never tried combustible tobacco is associated with risk of initiating use of 3 combustible tobacco products (ie, cigarettes, cigars, and hookah). Longitudinal repeated assessment of a school-based cohort at baseline (fall 2013, 9th grade, mean age = 14.1 years) and at a 6-month follow-up (spring 2014, 9th grade) and a 12-month follow-up (fall 2014, 10th grade). Ten public high schools in Los Angeles, California, were recruited through convenience sampling. Participants were students who reported never using combustible tobacco at baseline and completed follow-up assessments at 6 or 12 months (N = 2530). At each time point, students completed self-report surveys during in-classroom data collections. Student self-report of whether he or she ever used e-cigarettes (yes or no) at baseline. Six- and 12-month follow-up reports on use of any of the following tobacco products within the prior 6 months: (1) any combustible tobacco product (yes or no); (2) combustible cigarettes (yes or no), (3) cigars (yes or no); (4) hookah (yes or no); and (5) number of combustible tobacco products (range: 0-3). Past 6-month use of any combustible tobacco product was more frequent in baseline e-cigarette ever users (n = 222) than never users (n = 2308) at the 6-month follow-up (30.7% vs 8.1%, respectively; difference between groups in prevalence rates, 22.7% [95% CI, 16.4%-28.9%]) and at the 12-month follow-up (25.2% vs 9.3%, respectively; difference between groups, 15.9% [95% CI, 10.0%-21.8%]). Baseline e-cigarette use was associated with greater likelihood of use of any combustible tobacco product averaged across the 2 follow-up periods in the unadjusted analyses (odds ratio [OR], 4.27 [95% CI, 3.19-5.71]) and in the analyses adjusted for sociodemographic, environmental, and intrapersonal risk factors for smoking (OR, 2.73 [95% CI, 2.00-3.73]). Product-specific analyses showed that baseline e-cigarette use was positively associated with combustible cigarette (OR, 2.65 [95% CI, 1.73-4.05]), cigar (OR, 4.85 [95% CI, 3.38-6.96]), and hookah (OR, 3.25 [95% CI, 2.29-4.62]) use and with the number of different combustible products used (OR, 4.26 [95% CI, 3.16-5.74]) averaged across the 2 follow-up periods. Among high school students in Los Angeles, those who had ever used e-cigarettes at baseline compared with nonusers were more likely to report initiation of combustible tobacco use over the next year. Further research is needed to understand whether this association may be causal.

The artifcial catchment Chicken Creek as a tool to study initial ecosystem development

NASA Astrophysics Data System (ADS)

Schaaf, W.; Elmer, M.; Fischer, A.; Gerwin, W.; Nenov, R.

2011-12-01

The artificial catchment Chicken Creek was constructed in 2005 to study the increasingly complex interactions of processes and structures during initial development of ecosystems. The 6ha area serves as the central research site for the Transregional Collaborative Research Center 38. Both internal and external factors could be identified as driving forces for the formation of structures and patterns in the artificial catchment during the first five years of development. Initial structures formed by the construction process (e.g. catchment morphology, subsurface structures like clay dams and dumping cones, caterpillar tracks at the surface) and initial substrate characteristics (e.g. texture, geochemistry) were decisive both for the distribution and flow of precipitation water and for vegetation succession. External factors like episodic events (e.g. heavy thunderstorms) triggered erosion and dissection during this initial phase, promoted by the low vegetation cover and the unconsolidated sandy substrate. These processes resulted in transport and redistribution of water and sediment within the catchment, mainly along the main slope, and the formation of new structural elements like gullies and channels, a sedimentation fan above and sediments within the pond. As a result, we observed an overall differentiation of the site, e.g. with respect to water availability and texture redistribution, into areas with abrasion or accumulation processes dominating and areas with stable surfaces. During further development, both external factors and processes within the catchment continued to influence the site. For example, beside the initial soil seed bank, the surrounding environment of the catchment clearly affected species invasion. The dissection and stability of surfaces may be an important factor for the establishment of plants and habitats as well as for the formation of vegetation patterns and biological soil crusts. The transformation of the initial geo-system into areas with evolving terrestrial or aquatic characteristics and from a very episodic to a more permanent stream network and discharge, together with the observed vegetation dynamics increased site diversity and heterogeneity with respect to water and nutrient availability and transformation processes compared to the more homogenous conditions at point zero. We expect that these more permanent structures and patterns established after five years will greatly influence the future development of the catchment with respect to e.g. input and accumulation of soil organic matter, nitrogen input and availability by symbiotic microbial N-fixation, development of root systems and soil food webs, weathering and soil formation, element cycling, and the water and element budget at the catchment scale.

The current contribution of molecular factors to risk estimation in neuroblastoma patients.

PubMed

Berthold, F; Sahin, K; Hero, B; Christiansen, H; Gehring, M; Harms, D; Horz, S; Lampert, F; Schwab, M; Terpe, J

1997-10-01

The association of molecular characteristics with prognosis has been reported, but not their relationship with each other and their impact in the context of known clinical risk factors. In this study, data of 1249 consecutive intent-to-treat-neuroblastoma patients with more than 1 year follow-up were examined by multivariate analysis using loglinear and Cox proportional hazard regression models on a stage-related basis (stages 1-3: 600, 4S: 116, 4: 533). In a first step, risk factors were identified from 18 selected clinical variables, and risk groups defined. The second step investigated whether molecular characteristics (MYCN, LOH 1p, del 1p, CD44, N-ras, NGF-R, bcl-2, APO-1 (CD95)) contributed additional prognostic information to the model. The loglinear model demonstrated several interactions between clinical factors. By the Cox regression model, seven independent clinical risk factors were found for stages 1-3, seven for stage 4 and two for stage 4S. By subsequent introduction of all molecular variables, MYCN amplification only added significant prognostic information to the clinical factors in localised and stage 4 neuroblastoma. The models allowed the definition of risk groups for stages 1-3 patients by age (e beta = 5.09) and MYCN (e beta = 4.26), for stage 4 by MYCN (e beta = 2.78) and number of symptoms (e beta = 2.44) and for stage 4S by platelet count (e beta = 3.91) and general condition (e beta = 2.99). Molecular factors and in particular MYCN contribute significantly to risk estimation. In conjunction with clinical factors, they are powerful tools to define risk groups in neuroblastoma.

Four-year weight losses in the Look AHEAD study: factors associated with long-term success.

PubMed

Wadden, Thomas A; Neiberg, Rebecca H; Wing, Rena R; Clark, Jeanne M; Delahanty, Linda M; Hill, James O; Krakoff, Jonathan; Otto, Amy; Ryan, Donna H; Vitolins, Mara Z

2011-10-01

This report provides a further analysis of the year 4 weight losses in the Look AHEAD (Action for Health in Diabetes) study and identifies factors associated with long-term success. A total of 5,145 overweight/obese men and women with type 2 diabetes were randomly assigned to an intensive lifestyle intervention (ILI) or a usual care group, referred to as Diabetes Support and Education (DSE). ILI participants were provided approximately weekly group or individual treatment in year 1; continued but less frequent contact was provided in years 2-4. DSE participants received three group educational sessions in all years. As reported previously, at year 4, ILI participants lost an average of 4.7% of initial weight, compared with 1.1% for DSE (P < 0.0001). More ILI than DSE participants lost ≥ 5% (46% vs. 25%, P < 0.0001) and ≥ 10% (23% vs. 10%, P < 0.0001) of initial weight. Within the ILI, achievement of both the 5% and 10% categorical weight losses at year 4 was strongly related to meeting these goals at year 1. A total of 887 participants in ILI lost ≥ 10% at year 1, of whom 374 (42.2%) achieved this loss at year 4. Participants who maintained the loss, compared with those who did not, attended more treatment sessions and reported more favorable physical activity and food intake at year 4. These results provide critical evidence that a comprehensive lifestyle intervention can induce clinically significant weight loss (i.e., ≥ 5%) in overweight/obese participants with type 2 diabetes and maintain this loss in more than 45% of patients at 4 years.

WISE-MD usage among millennial medical students.

PubMed

Phitayakorn, Roy; Nick, Michael W; Alseidi, Adnan; Lind, David Scott; Sudan, Ranjan; Isenberg, Gerald; Capella, Jeannette; Hopkins, Mary A; Petrusa, Emil R

2015-01-01

E-learning is increasingly common in undergraduate medical education. Internet-based multimedia materials should be designed with millennial learner utilization preferences in mind for maximal impact. Medical students used all 20 Web Initiative for Surgical Education of Medical Doctors modules from July 1, 2013 to October 1, 2013. Data were analyzed for topic frequency, time and week day, and access to questions. Three thousand five hundred eighty-seven students completed 35,848 modules. Students accessed modules for average of 51 minutes. Most frequent use occurred on Sunday (23.1%), Saturday (15.4%), and Monday (14.3%). Friday had the least use (8.2%). A predominance of students accessed the modules between 7 and 10 PM (34.4%). About 80.4% of students accessed questions for at least one module. They completed an average of 40 ± 30 of the questions. Only 827 students (2.3%) repeated the questions. Web Initiative for Surgical Education of Medical Doctors has peak usage during the weekend and evenings. Most frequently used modules reflect core surgical problems. Multiple factors influence the manner module questions are accessed. Copyright © 2015 Elsevier Inc. All rights reserved.

Endoplasmic Reticulum Stress Induced Synthesis of a Novel Viral Factor Mediates Efficient Replication of Genotype-1 Hepatitis E Virus.

PubMed

Nair, Vidya P; Anang, Saumya; Subramani, Chandru; Madhvi, Abhilasha; Bakshi, Karishma; Srivastava, Akriti; Shalimar; Nayak, Baibaswata; Ranjith Kumar, C T; Surjit, Milan

2016-04-01

Hepatitis E virus (HEV) causes acute hepatitis in many parts of the world including Asia, Africa and Latin America. Though self-limiting in normal individuals, it results in ~30% mortality in infected pregnant women. It has also been reported to cause acute and chronic hepatitis in organ transplant patients. Of the seven viral genotypes, genotype-1 virus infects humans and is a major public health concern in South Asian countries. Sporadic cases of genotype-3 and 4 infection in human and animals such as pigs, deer, mongeese have been reported primarily from industrialized countries. Genotype-5, 6 and 7 viruses are known to infect animals such as wild boar and camel, respectively. Genotype-3 and 4 viruses have been successfully propagated in the laboratory in mammalian cell culture. However, genotype-1 virus replicates poorly in mammalian cell culture and no other efficient model exists to study its life cycle. Here, we report that endoplasmic reticulum (ER) stress promotes genotype-1 HEV replication by inducing cap-independent, internal initiation mediated translation of a novel viral protein (named ORF4). Importantly, ORF4 expression and stimulatory effect of ER stress inducers on viral replication is specific to genotype-1. ORF4 protein sequence is mostly conserved among genotype-1 HEV isolates and ORF4 specific antibodies were detected in genotype-1 HEV patient serum. ORF4 interacted with multiple viral and host proteins and assembled a protein complex consisting of viral helicase, RNA dependent RNA polymerase (RdRp), X, host eEF1α1 (eukaryotic elongation factor 1 isoform-1) and tubulinβ. In association with eEF1α1, ORF4 stimulated viral RdRp activity. Furthermore, human hepatoma cells that stably express ORF4 or engineered proteasome resistant ORF4 mutant genome permitted enhanced viral replication. These findings reveal a positive role of ER stress in promoting genotype-1 HEV replication and pave the way towards development of an efficient model of the virus.

Transplantation of polarized type 2 donor T cells reduces mortality caused by experimental graft-versus-host disease.

PubMed

Krenger, W; Cooke, K R; Crawford, J M; Sonis, S T; Simmons, R; Pan, L; Delmonte, J; Karandikar, M; Ferrara, J L

1996-11-15

Acute graft-versus-host disease (GVHD) is thought to be initiated by alloreactive type 1 T cells that secrete gamma-interferon (IFN-gamma). IFN-gamma induces the production of inflammatory cytokines, e.g., tumor necrosis factor-alpha and interleukin (IL)-1, which are the distal mediators of GVHD. We demonstrate that the transplantation of polarized type 2 murine T cells (i.e., cells secreting IL-4 but not IFN-gamma) together with T-cell-depleted bone marrow results in a significant increase in survival (P<0.001) after bone marrow transplantation across minor histocompatibility barriers (B10.BR-->CBA/J). Further analysis demonstrated that increased survival in recipients of polarized type 2 T cells correlated with diminished production of both IFN-gamma and tumor necrosis factor-alpha but with increases in IL-4 2 weeks after transplantation. Despite improved survival, histologic changes of GVHD were evident in oral mucosal and hepatic tissues at 7 weeks after bone marrow transplantation. These data provide further evidence that inflammatory cytokines in the immediate posttransplant period are pivotal to the development of mortality but that they do not correlate with individual target organ damage.

Smoking Attitudes and Practices among Low-Income African Americans: Qualitative Assessment of Contributing Factors.

ERIC Educational Resources Information Center

Beech, Bettina M.; Scarinci, Isabel C.

2003-01-01

Qualitatively examined sociocultural factors associated with smoking attitudes and practices among low-income, African American young adults smokers and nonsmokers. Focus group data indicated that specific contextual and familial factors contributed to smoking initiation, maintenance, and cessation (e.g., strong parental discipline, limited…

Transcription factors ETF, E2F, and SP-1 are involved in cytokine-independent proliferation of murine hepatocytes.

PubMed

Zellmer, Sebastian; Schmidt-Heck, Wolfgang; Godoy, Patricio; Weng, Honglei; Meyer, Christoph; Lehmann, Thomas; Sparna, Titus; Schormann, Wiebke; Hammad, Seddik; Kreutz, Clemens; Timmer, Jens; von Weizsäcker, Fritz; Thürmann, Petra A; Merfort, Irmgard; Guthke, Reinhard; Dooley, Steven; Hengstler, Jan G; Gebhardt, Rolf

2010-12-01

The cellular basis of liver regeneration has been intensely investigated for many years. However, the mechanisms initiating hepatocyte "plasticity" and priming for proliferation are not yet fully clear. We investigated alterations in gene expression patterns during the first 72 hours of C57BL/6N mouse hepatocyte culture on collagen monolayers (CM), which display a high basal frequency of proliferation in the absence of cytokines. Although many metabolic genes were down-regulated, genes related to mitogen-activated protein kinase (MAPK) signaling and cell cycle were up-regulated. The latter genes showed an overrepresentation of transcription factor binding sites (TFBS) for ETF (TEA domain family member 2), E2F1 (E2F transcription factor 1), and SP-1 (Sp1 transcription factor) (P < 0.001), all depending on MAPK signaling. Time-dependent increase of ERK1/2 phosphorylation occurred during the first 48 hours (and beyond) in the absence of cytokines, accompanied by an enhanced bromodeoxyuridine labeling index of 20%. The MEK inhibitor PD98059 blunted these effects indicating MAPK signaling as major trigger for this cytokine-independent proliferative response. In line with these in vitro findings, liver tissue of mice challenged with CCl(4) displayed hepatocytes with intense p-ERK1/2 staining and nuclear SP-1 and E2F1 expression. Furthermore, differentially expressed genes in mice after partial hepatectomy contained overrepresented TFBS for ETF, E2F1, and SP-1 and displayed increased expression of E2F1. Cultivation of murine hepatocytes on CM primes cells for proliferation through cytokine-independent activation of MAPK signaling. The transcription factors ETF, E2F1, and SP-1 seem to play a pronounced role in mediating proliferation-dependent differential gene expression. Similar events, but on a shorter time-scale, occur very early after liver damage in vivo. Copyright © 2010 American Association for the Study of Liver Diseases.

Mindfulness and Cardiovascular Disease Risk: State of the Evidence, Plausible Mechanisms, and Theoretical Framework.

PubMed

Loucks, Eric B; Schuman-Olivier, Zev; Britton, Willoughby B; Fresco, David M; Desbordes, Gaelle; Brewer, Judson A; Fulwiler, Carl

2015-12-01

The purpose of this review is to provide (1) a synopsis on relations of mindfulness with cardiovascular disease (CVD) and major CVD risk factors, and (2) an initial consensus-based overview of mechanisms and theoretical framework by which mindfulness might influence CVD. Initial evidence, often of limited methodological quality, suggests possible impacts of mindfulness on CVD risk factors including physical activity, smoking, diet, obesity, blood pressure, and diabetes regulation. Plausible mechanisms include (1) improved attention control (e.g., ability to hold attention on experiences related to CVD risk, such as smoking, diet, physical activity, and medication adherence), (2) emotion regulation (e.g., improved stress response, self-efficacy, and skills to manage craving for cigarettes, palatable foods, and sedentary activities), and (3) self-awareness (e.g., self-referential processing and awareness of physical sensations due to CVD risk factors). Understanding mechanisms and theoretical framework should improve etiologic knowledge, providing customized mindfulness intervention targets that could enable greater mindfulness intervention efficacy.

Mindfulness and Cardiovascular Disease Risk: State of the Evidence, Plausible Mechanisms, and Theoretical Framework

PubMed Central

Schuman-Olivier, Zev; Britton, Willoughby B.; Fresco, David M.; Desbordes, Gaelle; Brewer, Judson A.; Fulwiler, Carl

2016-01-01

The purpose of this review is to provide (1) a synopsis on relations of mindfulness with cardiovascular disease (CVD) and major CVD risk factors, and (2) an initial consensus-based overview of mechanisms and theoretical framework by which mindfulness might influence CVD. Initial evidence, often of limited methodological quality, suggests possible impacts of mindfulness on CVD risk factors including physical activity, smoking, diet, obesity, blood pressure, and diabetes regulation. Plausible mechanisms include (1) improved attention control (e.g., ability to hold attention on experiences related to CVD risk, such as smoking, diet, physical activity, and medication adherence), (2) emotion regulation (e.g., improved stress response, self-efficacy, and skills to manage craving for cigarettes, palatable foods, and sedentary activities), and (3) self-awareness (e.g., self-referential processing and awareness of physical sensations due to CVD risk factors). Understanding mechanisms and theoretical framework should improve etiologic knowledge, providing customized mindfulness intervention targets that could enable greater mindfulness intervention efficacy. PMID:26482755

Identification and characterization of thermotolerant acetic acid bacteria strains isolated from coconut water vinegar in Sri Lanka.

PubMed

Perumpuli, P A B N; Watanabe, Taisuke; Toyama, Hirohide

2014-01-01

From the pellicle formed on top of brewing coconut water vinegar in Sri Lanka, three Acetobacter strains (SL13E-2, SL13E-3, and SL13E-4) that grow at 42 °C and four Gluconobacter strains (SL13-5, SL13-6, SL13-7, and SL13-8) grow at 37 °C were identified as Acetobacter pasteurianus and Gluconobacter frateurii, respectively. Acetic acid production by the isolated Acetobacter strains was examined. All three strains gave 4% acetic acid from 6% initial ethanol at 37 °C, and 2.5% acetic acid from 4% initial ethanol at 40 °C. Compared with the two other strains, SL13E-4 showed both slower growth and slower acetic acid production. As well as the thermotolerant SKU1108 strain, the activities of the alcohol dehydrogenase and the aldehyde dehydrogenase of SL13E-2 and SL13E-4 were more stable than those of the mesophilic strain. The isolated strains were used to produce coconut water vinegar at higher temperatures than typically used for vinegar production.

The role of basic leucine zipper transcription factor E4BP4 in the immune system and immune-mediated diseases.

PubMed

Yin, Jinghua; Zhang, Jian; Lu, Qianjin

2017-07-01

Basic leucine zipper transcription factor E4BP4 (also known as NFIL3) has been implicated in the molecular and cellular mechanisms of functions and activities in mammals. The interactions between E4BP4 and major regulators of cellular processes have triggered significant interest in the roles of E4BP4 in the pathogenesis of certain chronic diseases. Indeed, novel discoveries have been emerging to illustrate the involvement of E4BP4 in multiple disorders. It is recognized that E4BP4 is extensively involved in some immune-mediated diseases, but the mechanisms of E4BP4 involvement in these complex diseases remain poorly defined. Here we review the regulatory mechanisms of E4BP4 engaging in not only the biological function but also the development of immune-mediated diseases, paving the way for future therapies. Copyright © 2017. Published by Elsevier Inc.

The translation initiation factor 3 subunit eIF3K interacts with PML and associates with PML nuclear bodies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salsman, Jayme; Pinder, Jordan; Tse, Brenda

2013-10-15

The promyelocytic leukemia protein (PML) is a tumor suppressor protein that regulates a variety of important cellular processes, including gene expression, DNA repair and cell fate decisions. Integral to its function is the ability of PML to form nuclear bodies (NBs) that serve as hubs for the interaction and modification of over 90 cellular proteins. There are seven canonical isoforms of PML, which encode diverse C-termini generated by alternative pre-mRNA splicing. Recruitment of specific cellular proteins to PML NBs is mediated by protein–protein interactions with individual PML isoforms. Using a yeast two-hybrid screen employing peptide sequences unique to PML isoformmore » I (PML-I), we identified an interaction with the eukaryotic initiation factor 3 subunit K (eIF3K), and in the process identified a novel eIF3K isoform, which we term eIF3K-2. We further demonstrate that eIF3K and PML interact both in vitro via pull-down assays, as well as in vivo within human cells by co-immunoprecipitation and co-immunofluorescence. In addition, eIF3K isoform 2 (eIF3K-2) colocalizes to PML bodies, particularly those enriched in PML-I, while eIF3K isoform 1 associates poorly with PML NBs. Thus, we report eIF3K as the first known subunit of the eIF3 translation pre-initiation complex to interact directly with the PML protein, and provide data implicating alternative splicing of both PML and eIF3K as a possible regulatory mechanism for eIF3K localization at PML NBs. - Highlights: • The PML-I C-terminus, encoded by exon 9, interacts with translation factor eIF3K. • We identify a novel eIF3K isoform that excludes exon 2 (eIF3K-2). • eIF3K-2 preferentially associates with PML bodies enriched in PML-I vs. PML-IV. • Alternative splicing of eIF3K regulates association with PML bodies.« less

AMCOM Hexavalent Chrome Free Initiatives

DTIC Science & Technology

2010-12-01

AMCOM Hexavalent Chrome Free Initiatives 1 December 2010 SERDP-ESTCP Symposium Washington DC Mark Feathers AMCOM G-4 Environmental Division... Hexavalent Chrome Free Initiatives 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f...system environmental life cycle sustainability. G-4 is actively engaged in initiatives to reduce the use of hexavalent chrome used in materials and

Conversion of a Replication Origin to a Silencer through a Pathway Shared by a Forkhead Transcription Factor and an S Phase Cyclin

PubMed Central

Casey, Laurieann; Patterson, Erin E.; Müller, Ulrika

2008-01-01

Silencing of the mating-type locus HMR in Saccharomyces cerevisiae requires DNA elements called silencers. To establish HMR silencing, the origin recognition complex binds the HMR-E silencer and recruits the silent information regulator (Sir)1 protein. Sir1 in turn helps establish silencing by stabilizing binding of the other Sir proteins, Sir2–4. However, silencing is semistable even in sir1Δ cells, indicating that SIR1-independent establishment mechanisms exist. Furthermore, the requirement for SIR1 in silencing a sensitized version of HMR can be bypassed by high-copy expression of FKH1 (FKH1hc), a conserved forkhead transcription factor, or by deletion of the S phase cyclin CLB5 (clb5Δ). FKH1hc caused only a modest increase in Fkh1 levels but effectively reestablished Sir2–4 chromatin at HMR as determined by Sir3-directed chromatin immunoprecipitation. In addition, FKH1hc prolonged the cell cycle in a manner distinct from deletion of its close paralogue FKH2, and it created a cell cycle phenotype more reminiscent to that caused by a clb5Δ. Unexpectedly, and in contrast to SIR1, both FKH1hc and clb5Δ established silencing at HMR using the replication origins, ARS1 or ARSH4, as complete substitutes for HMR-E (HMRΔE::ARS). HMRΔE::ARS1 was a robust origin in CLB5 cells. However, initiation by HMRΔE::ARS1 was reduced by clb5Δ or FKH1hc, whereas ARS1 at its native locus was unaffected. The CLB5-sensitivity of HMRΔE::ARS1 did not result from formation of Sir2–4 chromatin because sir2Δ did not rescue origin firing in clb5Δ cells. These and other data supported a model in which FKH1 and CLB5 modulated Sir2–4 chromatin and late-origin firing through opposing regulation of a common pathway. PMID:18045995

LGR4 modulates breast cancer initiation, metastasis, and cancer stem cells.

PubMed

Yue, Zhiying; Yuan, Zengjin; Zeng, Li; Wang, Ying; Lai, Li; Li, Jing; Sun, Peng; Xue, Xiwen; Qi, Junyi; Yang, Zhengfeng; Zheng, Yansen; Fang, Yuanzhang; Li, Dali; Siwko, Stefan; Li, Yi; Luo, Jian; Liu, Mingyao

2018-05-01

The fourth member of the leucine-rich repeat-containing GPCR family (LGR4, frequently referred to as GPR48) and its cognate ligands, R-spondins (RSPOs) play crucial roles in the development of multiple organs as well as the survival of adult stem cells by activation of canonical Wnt signaling. Wnt/β-catenin signaling acts to regulate breast cancer; however, the molecular mechanisms determining its spatiotemporal regulation are largely unknown. In this study, we identified LGR4 as a master controller of Wnt/β-catenin signaling-mediated breast cancer tumorigenesis, metastasis, and cancer stem cell (CSC) maintenance. LGR4 expression in breast tumors correlated with poor prognosis. Either Lgr4 haploinsufficiency or mammary-specific deletion inhibited mouse mammary tumor virus (MMTV)- PyMT- and MMTV- Wnt1-driven mammary tumorigenesis and metastasis. Moreover, LGR4 down-regulation decreased in vitro migration and in vivo xenograft tumor growth and lung metastasis. Furthermore, Lgr4 deletion in MMTV- Wnt1 tumor cells or knockdown in human breast cancer cells decreased the number of functional CSCs by ∼90%. Canonical Wnt signaling was impaired in LGR4-deficient breast cancer cells, and LGR4 knockdown resulted in increased E-cadherin and decreased expression of N-cadherin and snail transcription factor -2 ( SNAI2) (also called SLUG), implicating LGR4 in regulation of epithelial-mesenchymal transition. Our findings support a crucial role of the Wnt signaling component LGR4 in breast cancer initiation, metastasis, and breast CSCs.-Yue, Z., Yuan, Z., Zeng, L., Wang, Y., Lai, L., Li, J., Sun, P., Xue, X., Qi, J., Yang, Z., Zheng, Y., Fang, Y., Li, D., Siwko, S., Li, Y., Luo, J., Liu, M. LGR4 modulates breast cancer initiation, metastasis, and cancer stem cells.

32 CFR 989.4 - Initial considerations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... ENVIRONMENTAL IMPACT ANALYSIS PROCESS (EIAP) § 989.4 Initial considerations. Air Force personnel will: (a... CATEX from environmental impact analysis (appendix B). (c) Make environmental documents, comments, and... national security interests while at the same time considering important environmental factors. (g...

32 CFR 989.4 - Initial considerations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... ENVIRONMENTAL IMPACT ANALYSIS PROCESS (EIAP) § 989.4 Initial considerations. Air Force personnel will: (a... CATEX from environmental impact analysis (appendix B). (c) Make environmental documents, comments, and... national security interests while at the same time considering important environmental factors. (g...

32 CFR 989.4 - Initial considerations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... ENVIRONMENTAL IMPACT ANALYSIS PROCESS (EIAP) § 989.4 Initial considerations. Air Force personnel will: (a... CATEX from environmental impact analysis (appendix B). (c) Make environmental documents, comments, and... national security interests while at the same time considering important environmental factors. (g...

Molecular pathways mediating differential responses to lipopolysaccharide between human and baboon arterial endothelial cells.

PubMed

Shi, Qiang; Cox, Laura A; Glenn, Jeremy; Tejero, Maria E; Hondara, Vida; Vandeberg, John L; Wang, Xing Li

2010-02-01

1. Vascular inflammation plays a critical role in atherogenesis. Previously, we showed that baboon arterial endothelial cells (BAEC) were hyporesponsive to lipopolysaccharide (LPS) compared with human arterial endothelial cells (HAEC). 2. In the present study, we investigated mechanisms underlying differential responses between HAEC and BAEC to tumour necrosis factor (TNF)-alpha and LPS. 3. Both HAEC and BAEC responded similarly to TNF-alpha. However, BAEC showed retarded responses to LPS in expression of E-selectin, intercellular adhesion molecule-1, monocyte chemotactic protein-1 and interleukin-8 (P < 0.05). These changes were confirmed at the mRNA level. Tumour necrosis factor-alpha activated nuclear factor-kappaB members such as p50, p52, p65, c-rel and RelB in both HAEC and BAEC. In contrast, LPS activated p50 and p65 only in HAEC. Using microarray assays, we found that TNF receptor-associated factor 2 (TRAF-2), TNF receptor superfamily, member 1A-associated via death domain (TRADD) and nuclear factors such as nuclear factor of kappa in B-cells inhibitor, alpha (NFKBIA) and nuclear factor of kappa in B-cells inhibitor, beta (NFKBIB) were upregulated by LPS only in HAEC. Although the baseline expression of Toll-like receptor (TLR) 4 was low in both HAEC and BAEC, TNF-alpha activated TLR4 expression in both cell types. Although LPS increased TLR4 expression only in HAEC, human and baboon peripheral blood mononuclear cells exhibited similar TLR4 expression and response to LPS. Transfecting BAEC with TLR4/myeloid differentiation protein-2 overexpression vector conferred BAEC responsiveness to LPS. 4. The findings of the present study indicate that an altered TLR4 system may be responsible for the resistance of baboon endothelial cells to LPS. Given the importance of TLR4 in human immune responses and vascular diseases, the natural resistance of baboons to LPS/TLR4-initiated inflammation could make the baboon a valuable animal model in which to study how inflammation affects atherogenesis.

The Engineering 4 Health Challenge - an interdisciplinary and intercultural initiative to foster student engagement in B.C. and improve health care for children in under-serviced communities.

PubMed

Price, Morgan; Weber-Jahnke, Jens H

2009-01-01

This paper describes the Engineering 4 Health (E4H) Challenge, an interdisciplinary and intercultural initiative that, on the one hand, seeks to improve health education of children in under-serviced communities and, on the other, seeks to attract students in British Columbia to professions in engineering and health. The E4H Challenge engages high school and university students in BC to cooperatively design and develop health information and communication technology (ICT) to educate children living in under-serviced communities. The E4H Challenge works with the One Laptop Per Child (OLPC) program to integrate applications for health awareness into the school programs of communities in developing countries. Although applications developed by the E4H Challenge use the low-cost, innovative XO laptop (the "$100 laptop" developed by the OLPC foundation) the software can also be used with other inexpensive hardware.

Abiotic and biotic determinants of coarse woody productivity in temperate mixed forests.

PubMed

Yuan, Zuoqiang; Ali, Arshad; Wang, Shaopeng; Gazol, Antonio; Freckleton, Robert; Wang, Xugao; Lin, Fei; Ye, Ji; Zhou, Li; Hao, Zhanqing; Loreau, Michel

2018-07-15

Forests play an important role in regulating the global carbon cycle. Yet, how abiotic (i.e. soil nutrients) and biotic (i.e. tree diversity, stand structure and initial biomass) factors simultaneously contribute to aboveground biomass (coarse woody) productivity, and how the relative importance of these factors changes over succession remain poorly studied. Coarse woody productivity (CWP) was estimated as the annual aboveground biomass gain of stems using 10-year census data in old growth and secondary forests (25-ha and 4.8-ha, respectively) in northeast China. Boosted regression tree (BRT) model was used to evaluate the relative contribution of multiple metrics of tree diversity (taxonomic, functional and phylogenetic diversity and trait composition as well as stand structure attributes), stand initial biomass and soil nutrients on productivity in the studied forests. Our results showed that community-weighted mean of leaf phosphorus content, initial stand biomass and soil nutrients were the three most important individual predictors for CWP in secondary forest. Instead, initial stand biomass, rather than diversity and functional trait composition (vegetation quality) was the most parsimonious predictor of CWP in old growth forest. By comparing the results from secondary and old growth forest, the summed relative contribution of trait composition and soil nutrients on productivity decreased as those of diversity indices and initial biomass increased, suggesting the stronger effect of diversity and vegetation quantity over time. Vegetation quantity, rather than diversity and soil nutrients, is the main driver of forest productivity in temperate mixed forest. Our results imply that diversity effect for productivity in natural forests may not be so important as often suggested, at least not during the later stage of forest succession. This finding suggests that as a change of the importance of different divers of productivity, the environmentally driven filtering decreases and competitively driven niche differentiation increases with forest succession. Copyright © 2018 Elsevier B.V. All rights reserved.

E1B-55K mediated regulation of RNF4 STUbL promotes HAdV gene expression.

PubMed

Müncheberg, Sarah; Hay, Ron T; Ip, Wing H; Meyer, Tina; Weiß, Christina; Brenke, Jara; Masser, Sawinee; Hadian, Kamyar; Dobner, Thomas; Schreiner, Sabrina

2018-04-25

HAdV E1B-55K is a multifunctional regulator of productive viral replication and oncogenic transformation in non-permissive mammalian cells. These functions depend on E1B-55K's posttranslational modification with the SUMO protein and its binding to HAdV E4orf6. Both early viral proteins recruit specific host factors to form an E3 Ubiquitin ligase complex that targets antiviral host substrates for proteasomal degradation. Recently, we reported that the PML-NB-associated factor Daxx represses efficient HAdV productive infection and is proteasomally degraded via a SUMO-E1B-55K-dependent, E4orf6-independent pathway, the details of which remained to be established.RNF4, a cellular SUMO-targeted Ubiquitin ligase (STUbL), induces ubiquitinylation of specific SUMOylated proteins and plays an essential role during DNA repair. Here, we show that E1B-55K recruits RNF4 to the insoluble nuclear matrix fraction of the infected cell to support RNF4/Daxx association, promoting Daxx PTM, and thus inhibiting this antiviral factor. Removing RNF4 from infected cells using RNAi resulted in blocking the proper establishment of viral replication centers and significantly diminished viral gene expression. These results provide a model for how HAdV antagonize the antiviral host responses by exploiting the functional capacity of cellular STUbLs. Thus, RNF4 and its STUbL function represent a positive factor during lytic infection and a novel candidate for future therapeutic antiviral intervention strategies. IMPORTANCE Daxx is a PML-NB-associated transcription factor, which was recently shown to repress efficient HAdV productive infection. To counteract this antiviral measurement during infection, Daxx is degraded via a novel pathway including viral E1B-55K and host proteasomes. This virus-mediated degradation is independent of the classical HAdV E3 Ubiquitin ligase complex, which is essential during viral infection to target other host antiviral substrates. To maintain productive viral life cycle, HAdV E1B-55K early viral protein inhibits the chromatin-remodeling factor Daxx in a SUMO-dependent manner. In addition viral E1B-55K protein recruits the STUbL RNF4 and sequesters it into the insoluble fraction of the infected cell. E1B-55K promotes complex formation between RNF4 and E1B-55K targeted Daxx protein, supporting Daxx posttranslational modification prior to functional inhibition. Hence, RNF4 represents a novel host factor, which is beneficial for HAdV gene expression by supporting Daxx counteraction. In this regard, RNF4 and other STUbL proteins might represent novel targets for therapeutic intervention. Copyright © 2018 American Society for Microbiology.

Activation of translation complex eIF4F is essential for the genesis and maintenance of the malignant phenotype in human mammary epithelial cells.

PubMed

Avdulov, Svetlana; Li, Shunan; Michalek, Van; Burrichter, David; Peterson, Mark; Perlman, David M; Manivel, J Carlos; Sonenberg, Nahum; Yee, Douglas; Bitterman, Peter B; Polunovsky, Vitaly A

2004-06-01

Common human malignancies acquire derangements of the translation initiation complex, eIF4F, but their functional significance is unknown. Hypophosphorylated 4E-BP proteins negatively regulate eIF4F assembly by sequestering its mRNA cap binding component eIF4E, whereas hyperphosphorylation abrogates this function. We found that breast carcinoma cells harbor increases in the eIF4F constituent eIF4GI and hyperphosphorylation of 4E-BP1 which are two alterations that activate eIF4F assembly. Ectopic expression of eIF4E in human mammary epithelial cells enabled clonal expansion and anchorage-independent growth. Transfer of 4E-BP1 phosphorylation site mutants into breast carcinoma cells suppressed their tumorigenicity, whereas loss of these 4E-BP1 phosphorylation site mutants accompanied spontaneous reversion to a malignant phenotype. Thus, eIF4F activation is an essential component of the malignant phenotype in breast carcinoma.

First measurement of proton's charge form factor at very low Q 2 with initial state radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mihovilovič, M.; Weber, A. B.; Achenbach, P.

Here we report on a new experimental method based on initial-state radiation (ISR) in e–pscattering, which exploits the radiative tail of the elastic peak to study the properties of electromagnetic processes and to extract the proton charge form factor (Gmore » $$p\\atop{E}$$) at extremely small Q 2. The ISR technique was implemented in an experiment at the three-spectrometer facility of the Mainz Microtron (MAMI). This led to a precise validation of radiative corrections far away from elastic line and provided first measurements of G$$p\\atop{E}$$ for 0.001 ≤Q 2≤0.004 (GeV/c) 2.« less

First measurement of proton's charge form factor at very low Q 2 with initial state radiation

DOE PAGES

Mihovilovič, M.; Weber, A. B.; Achenbach, P.; ...

2017-05-15

Here we report on a new experimental method based on initial-state radiation (ISR) in e–pscattering, which exploits the radiative tail of the elastic peak to study the properties of electromagnetic processes and to extract the proton charge form factor (Gmore » $$p\\atop{E}$$) at extremely small Q 2. The ISR technique was implemented in an experiment at the three-spectrometer facility of the Mainz Microtron (MAMI). This led to a precise validation of radiative corrections far away from elastic line and provided first measurements of G$$p\\atop{E}$$ for 0.001 ≤Q 2≤0.004 (GeV/c) 2.« less

Pou5f1-dependent EGF expression controls E-cad endocytosis, cell adhesion, and zebrafish epiboly movements

PubMed Central

Song, Sungmin; Eckerle, Stephanie; Onichtchouk, Daria; Marrs, James A.; Nitschke, Roland; Driever, Wolfgang

2013-01-01

Summary Initiation of motile cell behavior in embryonic development occurs during late blastula stages when gastrulation begins. At this stage, the strong adhesion of blastomeres has to be modulated to enable dynamic behavior, similar to epithelial-to-mesenchymal transitions. We show that in zebrafish MZspg embryos mutant for the stem cell transcription factor Pou5f1/Oct4, which are severely delayed in the epiboly gastrulation movement, all blastomeres are defective in E-cad endosomal trafficking and E-cad accumulates at the plasma membrane. We find that Pou5f1-dependent control of EGF expression regulates endosomal E-cad trafficking. EGFR may act via modulation of p120 activity. Loss of E-cad dynamics reduces cohesion of cells in reaggregation assays. Quantitative analysis of cell behavior indicates that dynamic E-cad endosomal trafficking is required for epiboly cell movements. We hypothesize that dynamic control of E-cad trafficking is essential to effectively generate new adhesion sites when cells move relative to each other. PMID:23484854

Excessive Cap-dependent Translation as a Molecular Mechanism Underlying ASD

DTIC Science & Technology

2012-08-01

SUPPLEMENTARY NOTES 14. ABSTRACT We hypothesize that excessive cap-dependent translation is a causative factor in autism spectrum disorder...compounds to therapeutically target eIF4E-eIF4G interactions and eIF4A for treating patients with ASD. 15. SUBJECT TERMS autism spectrum...Introduction We hypothesize that excessive cap-dependent translation is a causative factor in autism spectrum disorder (ASD). To test this

Acute molecular response of mouse hindlimb muscles to chronic stimulation.

PubMed

LaFramboise, W A; Jayaraman, R C; Bombach, K L; Ankrapp, D P; Krill-Burger, J M; Sciulli, C M; Petrosko, P; Wiseman, R W

2009-09-01

Stimulation of the mouse hindlimb via the sciatic nerve was performed for a 4-h period to investigate acute muscle gene activation in a model of muscle phenotype conversion. Initial force production (1.6 +/- 0.1 g/g body wt) declined 45% within 10 min and was maintained for the remainder of the experiment. Force returned to initial levels upon study completion. An immediate-early growth response was present in the extensor digitorum longus (EDL) muscle (FOS, JUN, activating transcription factor 3, and musculoaponeurotic fibrosarcoma oncogene) with a similar but attenuated pattern in the soleus muscle. Transcript profiles showed decreased fast fiber-specific mRNA (myosin heavy chains 2A and 2B, fast troponins T(3) and I, alpha-tropomyosin, muscle creatine kinase, and parvalbumin) and increased slow transcripts (myosin heavy chain-1beta/slow, troponin C slow, and tropomyosin 3y) in the EDL versus soleus muscles. Histological analysis of the EDL revealed glycogen depletion without inflammatory cell infiltration in stimulated versus control muscles, whereas ultrastructural analysis showed no evidence of myofiber damage after stimulation. Multiple fiber type-specific transcription factors (tea domain family member 1, nuclear factor of activated T cells 1, peroxisome proliferator-activated receptor-gamma coactivator-1alpha and -beta, circadian locomotor output cycles kaput, and hypoxia-inducible factor-1alpha) increased in the EDL along with transcription factors characteristic of embryogenesis (Kruppel-like factor 4; SRY box containing 17; transcription factor 15; PBX/knotted 1 homeobox 1; and embryonic lethal, abnormal vision). No established in vivo satellite cell markers or genes activated in our parallel experiments of satellite cell proliferation in vitro (cyclins A(2), B(2), C, and E(1) and MyoD) were differentially increased in the stimulated muscles. These results indicated that the molecular onset of fast to slow phenotype conversion occurred in the EDL within 4 h of stimulation without injury or satellite cell recruitment. This conversion was associated with the expression of phenotype-specific transcription factors from resident fiber myonuclei, including the activation of nascent developmental transcriptional programs.

The let-7 microRNA interfaces extensively with the translation machinery to regulate cell differentiation

PubMed Central

Ding, Xavier C.; Slack, Frank J.; Großhans, Helge

2010-01-01

MicroRNAs (miRNAs) are noncoding RNAs that regulate numerous target genes through a posttranscriptional mechanism and thus control major developmental pathways. The phylogenetically conserved let-7 miRNA regulates cell proliferation and differentiation, thus functioning as a key regulator of developmental timing in C. elegans and a tumor suppressor gene in humans. Using a reverse genetic screen, we have identified genetic interaction partners of C. elegans let-7, including known and novel potential target genes. Initial identification of several translation initiation factors as suppressors of a let-7 mutation led us to systematically examine genetic interaction between let-7 and the translational machinery, which we found to be widespread. In the presence of wild-type let-7, depletion of the translation initiation factor eIF3 resulted in precocious cell differentiation, suggesting that developmental timing is translationally regulated, possibly by let-7. As overexpression of eIF3 in humans promotes translation of mRNAs that are also targets of let-7-mediated repression, we suggest that eIF3 may directly or indirectly oppose let-7 activity. This might provide an explanation for the opposite functions of let-7 and eIF3 in regulating tumorigenesis. PMID:18818519

Selection of relatively exact reference genes for gene expression studies in goosegrass (Eleusine indica) under herbicide stress.

PubMed

Chen, Jingchao; Huang, Zhaofeng; Huang, Hongjuan; Wei, Shouhui; Liu, Yan; Jiang, Cuilan; Zhang, Jie; Zhang, Chaoxian

2017-04-21

Goosegrass (Eleusine indica) is one of the most serious annual grassy weeds worldwide, and its evolved herbicide-resistant populations are more difficult to control. Quantitative real-time PCR (qPCR) is a common technique for investigating the resistance mechanism; however, there is as yet no report on the systematic selection of stable reference genes for goosegrass. This study proposed to test the expression stability of 9 candidate reference genes in goosegrass in different tissues and developmental stages and under stress from three types of herbicide. The results show that for different developmental stages and organs (control), eukaryotic initiation factor 4 A (eIF-4) is the most stable reference gene. Chloroplast acetolactate synthase (ALS) is the most stable reference gene under glyphosate stress. Under glufosinate stress, eIF-4 is the best reference gene. Ubiquitin-conjugating enzyme (UCE) is the most stable reference gene under quizalofop-p-ethyl stress. The gene eIF-4 is the recommended reference gene for goosegrass under the stress of all three herbicides. Moreover, pairwise analysis showed that seven reference genes were sufficient to normalize the gene expression data under three herbicides treatment. This study provides a list of reliable reference genes for transcript normalization in goosegrass, which will facilitate resistance mechanism studies in this weed species.

Effects of Psychological and Social Work Factors on Self-Reported Sleep Disturbance and Difficulties Initiating Sleep

PubMed Central

Vleeshouwers, Jolien; Knardahl, Stein; Christensen, Jan Olav

2016-01-01

Study Objectives: This prospective cohort study examined previously underexplored relations between psychological/social work factors and troubled sleep in order to provide practical information about specific, modifiable factors at work. Methods: A comprehensive evaluation of a range of psychological/social work factors was obtained by several designs; i.e., cross-sectional analyses at baseline and follow-up, prospective analyses with baseline predictors (T1), prospective analyses with average exposure across waves as predictor ([T1 + T2] / 2), and prospective analyses with change in exposure from baseline to follow-up as predictor. Participants consisted of a sample of Norwegian employees from a broad spectrum of occupations, who completed a questionnaire at two points in time, approximately two years apart. Cross-sectional analyses at T1 comprised 7,459 participants, cross-sectional analyses at T2 included 6,688 participants. Prospective analyses comprised a sample 5,070 of participants who responded at both T1 and T2. Univariable and multivariable ordinal logistic regressions were performed. Results: Thirteen psychological/social work factors and two aspects of troubled sleep, namely difficulties initiating sleep and disturbed sleep, were studied. Ordinal logistic regressions revealed statistically significant associations for all psychological and social work factors in at least one of the analyses. Psychological and social work factors predicted sleep problems in the short term as well as the long term. Conclusions: All work factors investigated showed statistically significant associations with both sleep items, however quantitative job demands, decision control, role conflict, and support from superior were the most robust predictors and may therefore be suitable targets of interventions aimed at improving employee sleep. Citation: Vleeshouwers J, Knardahl S, Christensen JO. Effects of psychological and social work factors on self-reported sleep disturbance and difficulties initiating sleep. SLEEP 2016;39(4):833–846. PMID:26446114

Renal outcomes of agalsidase beta treatment for Fabry disease: role of proteinuria and timing of treatment initiation

PubMed Central

Ortiz, Alberto; Mauer, Michael; Linthorst, Gabor E.; Oliveira, João P.; Serra, Andreas L.; Maródi, László; Mignani, Renzo; Vujkovac, Bojan; Beitner-Johnson, Dana; Lemay, Roberta; Cole, J.Alexander; Svarstad, Einar; Waldek, Stephen; Germain, Dominique P.; Wanner, Christoph

2012-01-01

Background. The purpose of this study was to identify determinants of renal disease progression in adults with Fabry disease during treatment with agalsidase beta. Methods. Renal function was evaluated in 151 men and 62 women from the Fabry Registry who received agalsidase beta at an average dose of 1 mg/kg/2 weeks for at least 2 years. Patients were categorized into quartiles based on slopes of estimated glomerular filtration rate (eGFR) during treatment. Multivariate logistic regression analyses were used to identify factors associated with renal disease progression. Results. Men within the first quartile had a mean eGFR slope of –0.1 mL/min/1.73m2/year, whereas men with the most rapid renal disease progression (Quartile 4) had a mean eGFR slope of –6.7 mL/min/1.73m2/year. The risk factor most strongly associated with renal disease progression was averaged urinary protein:creatinine ratio (UP/Cr) ≥1 g/g (odds ratio 112, 95% confidence interval (95% CI) 4–3109, P = 0.0054). Longer time from symptom onset to treatment was also associated with renal disease progression (odds ratio 19, 95% CI 2–184, P = 0.0098). Women in Quartile 4 had the highest averaged UP/Cr (mean 1.8 g/g) and the most rapid renal disease progression: (mean slope –4.4 mL/min/1.73m2/year). Conclusions. Adults with Fabry disease are at risk for progressive loss of eGFR despite enzyme replacement therapy, particularly if proteinuria is ≥1 g/g. Men with little urinary protein excretion and those who began receiving agalsidase beta sooner after the onset of symptoms had stable renal function. These findings suggest that early intervention may lead to optimal renal outcomes. PMID:21804088

Higher risk of renal impairment associated with tenofovir use amongst people living with HIV in India: a comparative cohort analysis between Western India and United Kingdom.

PubMed

Pujari, Sanjay N; Smith, Colette; Makane, Abhimanyu; Youle, Mike; Johnson, Margaret; Bele, Vivek; Joshi, Kedar; Dabhade, Digamber; Bhagani, Sanjay

2014-03-29

Data on the renal safety of Tenofovir (TDF) in Low and Middle Income Countries (LMICs) is scarce. We compared development of various forms of renal impairment with use of TDF-containing antiretroviral therapy (ART) between a cohort from the Institute of Infectious Diseases (IID) Pune, Western India and the Royal Free Hospital (RFH) London, UK. This is a retrospective analysis of change in estimated glomerular filtration rates (eGFRs) at 6, 12 and 24 months post TDF initiation using the Modification of Diet in Renal Disease (MDRD) equation. In people living with Human Immunodeficiency virus (PLHIV) with pre-TDF eGFR > 90 ml/min/1.73 m2 time to development of and factors associated with progression to eGFR < 60 ml/min/1.73 m2 were calculated using standard survival methods. A total of 574 (59% Caucasian) at the RFH, and 708 (100% Indian ethnicity) PLHIV from IID were included. Baseline median eGFR were similar; RFH 102 (IQR 89, 117), IID 100 (82, 119). At 24 months, mean (SD) decline in eGFR was -7(21) at RFH (p < 0.0001) and -7(40) at IID (p = 0.001). Amongst those with pre-TDF eGFR > 90 ml/min/1.73 m2 PLHIV at IID were more likely to develop an eGFR < 60 ml/min/1.73 m2 (aHR = 7.6 [95% CI 3.4, 17.4] p < 0.0001) and had a faster rate of progression estimated using Kaplan Meier methods. Risk factors included age (per 10 years older: aHR = 2.21 [1.6, 3.0] p < 0.0001) and receiving concomitant ritonavir boosted Protease Inhibitor (PI/r) (aHR = 2.4 [1.2, 4.8] p = 0.01). There is higher frequency of treatment limiting renal impairment events amongst PLHIV receiving TDF in Western India. As TDF scale up progresses, programs need to develop capacity for monitoring and treatment of renal impairment associated with TDF.

Predictors of Optimal Cognitive Aging in 80+ Women: The Women’s Health Initiative Memory Study

PubMed Central

Rapp, Stephen R.; Hogan, Patricia E.; Driscoll, Ira; Tindle, Hilary A.; Smith, J. Carson; Kesler, Shelli R.; Zaslavsky, Oleg; Rossom, Rebecca C.; Ockene, Judith K.; Yaffe, Kristine; Manson, JoAnn E.; Resnick, Susan M.; Espeland, Mark A.

2016-01-01

Background. Independent predictors of preserved cognitive functioning and factors associated with maintaining high preserved cognitive function in women ≥80 years remain elusive. Methods. Two thousand two hundred twenty-eight women with a mean age of 85 years who participated in the Women’s Health Initiative Memory Study were classified as cognitively normal (n = 1,905, 85.5%), mild cognitive impairment (n = 88, 3.9%), dementia (n = 121, 5.4%) or other cognitive impairment (n = 114, n = 5.1%) by central adjudication. Global cognitive functioning was assessed using telephone interview for cognitive status-modified in those women who did not meet cognitive impairment criteria. Differences between women grouped by cognitive status with respect to each potential risk factor were assessed using chi-squared tests and t-tests. Backward stepwise logistic regression was used to select factors that were independently associated with cognitive status. Results. Factors associated with preserved cognitive functioning were younger age, higher education, and family incomes, being non-Hispanic white, better emotional wellbeing, fewer depressive symptoms, more insomnia complaints, being free of diabetes, and not carrying the apolipoprotein E-epsilon 4 allele. Cognitively normal women who demonstrated sustained high preserved cognition were younger, more educated, and endorsed better self-reported general health, emotional wellbeing, and higher physical functioning. Conclusions. Addressing sociodemographic disparities such as income inequality, and targeting interventions to improve depressive symptoms and vascular risk factors, including diabetes, may play an important role in preserving cognition among women who survive to 80 years of age. Person-centered approaches that combine interventions to improve physical, cognitive, and psychosocial functioning may promote maintenance of high preserved cognitive health in the oldest-old. PMID:26858326

Virologic outcomes in early antiretroviral treatment: HPTN 052.

PubMed

Eshleman, Susan H; Wilson, Ethan A; Zhang, Xinyi C; Ou, San-San; Piwowar-Manning, Estelle; Eron, Joseph J; McCauley, Marybeth; Gamble, Theresa; Gallant, Joel E; Hosseinipour, Mina C; Kumarasamy, Nagalingeswaran; Hakim, James G; Kalonga, Ben; Pilotto, Jose H; Grinsztejn, Beatriz; Godbole, Sheela V; Chotirosniramit, Nuntisa; Santos, Breno Riegel; Shava, Emily; Mills, Lisa A; Panchia, Ravindre; Mwelase, Noluthando; Mayer, Kenneth H; Chen, Ying Q; Cohen, Myron S; Fogel, Jessica M

2017-05-01

The HIV Prevention Trials Network (HPTN) 052 trial demonstrated that early antiretroviral therapy (ART) prevented 93% of HIV transmission events in serodiscordant couples. Some linked infections were observed shortly after ART initiation or after virologic failure. To evaluate factors associated with time to viral suppression and virologic failure in participants who initiated ART in HPTN 052. 1566 participants who had a viral load (VL) > 400 copies/mL at enrollment were included in the analyses. This included 832 in the early ART arm (CD4 350-550 cells/mm 3 at ART initiation) and 734 in the delayed ART arm (204 with a CD4 < 250 cells/mm 3 at ART initiation; 530 with any CD4 at ART initiation). Viral suppression was defined as two consecutive VLs ≤ 400 copies/mL after ART initiation; virologic failure was defined as two consecutive VLs > 1000 copies/mL > 24 weeks after ART initiation. Overall, 93% of participants achieved viral suppression by 12 months. The annual incidence of virologic failure was 3.6%. Virologic outcomes were similar in the two study arms. Longer time to viral suppression was associated with younger age, higher VL at ART initiation, and region (Africa vs. Asia). Virologic failure was strongly associated with younger age, lower educational level, and lack of suppression by three months; lower VL and higher CD4 at ART initiation were also associated with virologic failure. Several clinical and demographic factors were identified that were associated with longer time to viral suppression and virologic failure. Recognition of these factors may help optimize ART for HIV treatment and prevention.

Virologic outcomes in early antiretroviral treatment: HPTN 052

PubMed Central

Eshleman, Susan H.; Wilson, Ethan A.; Zhang, Xinyi C.; Ou, San-San; Piwowar-Manning, Estelle; Eron, Joseph J.; McCauley, Marybeth; Gamble, Theresa; Gallant, Joel E.; Hosseinipour, Mina C.; Kumarasamy, Nagalingeswaran; Hakim, James G.; Kalonga, Ben; Pilotto, Jose H.; Grinsztejn, Beatriz; Godbole, Sheela V.; Chotirosniramit, Nuntisa; Santos, Breno Riegel; Shava, Emily; Mills, Lisa A.; Panchia, Ravindre; Mwelase, Noluthando; Mayer, Kenneth H.; Chen, Ying Q.; Cohen, Myron S.; Fogel, Jessica M.

2017-01-01

INTRODUCTION The HPTN 052 trial demonstrated that early antiretroviral therapy (ART) prevented 93% of HIV transmission events in serodiscordant couples. Some linked infections were observed shortly after ART initiation or after virologic failure. OBJECTIVE To evaluate factors associated with time to viral suppression and virologic failure in participants who initiated ART in HPTN 052. METHODS 1,566 participants who had a viral load (VL) >400 copies/mL at enrollment were included in the analyses. This included 832 in the early ART arm (CD4 350–550 cells/mm3 at ART initiation) and 734 in the delayed ART arm (204 with a CD4 <250 cells/mm3 at ART initiation; 530 with any CD4 at ART initiation). Viral suppression was defined as two consecutive VLs ≤400 copies/mL after ART initiation; virologic failure was defined as two consecutive VLs >1,000 copies/mL >24 weeks after ART initiation. RESULTS Overall, 93% of participants achieved viral suppression by 12 months. The annual incidence of virologic failure was 3.6%. Virologic outcomes were similar in the two study arms. Longer time to viral suppression was associated with younger age, higher VL at ART initiation, and region (Africa vs. Asia). Virologic failure was strongly associated with younger age, lower educational level, and lack of suppression by 3 months; lower VL and higher CD4 at ART initiation were also associated with virologic failure. CONCLUSIONS Several clinical and demographic factors were identified that were associated with longer time to viral suppression and virologic failure. Recognition of these factors may help optimize ART for HIV treatment and prevention. PMID:28385131

Stress-dependent relocalization of translationally primed mRNPs to cytoplasmic granules that are kinetically and spatially distinct from P-bodies.

PubMed

Hoyle, Nathaniel P; Castelli, Lydia M; Campbell, Susan G; Holmes, Leah E A; Ashe, Mark P

2007-10-08

Cytoplasmic RNA granules serve key functions in the control of messenger RNA (mRNA) fate in eukaryotic cells. For instance, in yeast, severe stress induces mRNA relocalization to sites of degradation or storage called processing bodies (P-bodies). In this study, we show that the translation repression associated with glucose starvation causes the key translational mediators of mRNA recognition, eIF4E, eIF4G, and Pab1p, to resediment away from ribosomal fractions. These mediators then accumulate in P-bodies and in previously unrecognized cytoplasmic bodies, which we define as EGP-bodies. Our kinetic studies highlight the fundamental difference between EGP- and P-bodies and reflect the complex dynamics surrounding reconfiguration of the mRNA pool under stress conditions. An absence of key mRNA decay factors from EGP-bodies points toward an mRNA storage function for these bodies. Overall, this study highlights new potential control points in both the regulation of mRNA fate and the global control of translation initiation.

The effects of lacosamide on depression and anxiety in patients with epilepsy.

PubMed

Moseley, Brian D; Cole, Devlin; Iwuora, Ogonna; Strawn, Jeffrey R; Privitera, Michael

2015-02-01

Depression and anxiety are common in patients with epilepsy. Moreover, some antiepileptic drugs (AEDs) have mood stabilizing and anxiolytic effects, while others may worsen psychiatric symptoms. The effects of lacosamide, a third generation AED approved for the treatment of focal onset seizures, on depressive and anxiety symptoms are unknown. We evaluated changes in depression and anxiety following the initiation of lacosamide. We compared patients' scores on the Neurological Disorders Depression Inventory for Epilepsy (NDDI-E, n = 91) and Generalized Anxiety Disorder 7-item (GAD-7, n = 20) scales prior to and following lacosamide treatment. Following the initiation of lacosamide, there were no significant changes in NDDI-E scores when all patients were analyzed aggregately (baseline: 12.14 ± 4.64 vs post-treatment: 11.91 ± 4.14, p = 0.51). Similarly, the mean GAD-7 scores at baseline (4.10 ± 4.52) and after treatment (4.75 ± 5.51) did not differ (p = 0.23). In the 25 patients with initial NDDI-E scores of >15, lacosamide was associated with a significant decrease in depressive symptoms (baseline: 17.60 ± 1.63 vs post-treatment: 14.64 ± 2.78, p < 0.001). NDDI-E and GAD-7 scores pre- and post-lacosamide initiation were not significantly affected by a history of mood disorders, concomitant psychiatric medications, or concomitant AEDs with mood-stabilizing effects. Copyright © 2014 Elsevier B.V. All rights reserved.

Development and Initial Validation of the Five-Factor Model Adolescent Personality Questionnaire (FFM-APQ).

PubMed

Rogers, Mary E; Glendon, A Ian

2018-01-01

This research reports on the 4-phase development of the 25-item Five-Factor Model Adolescent Personality Questionnaire (FFM-APQ). The purpose was to develop and determine initial evidence for validity of a brief adolescent personality inventory using a vocabulary that could be understood by adolescents up to 18 years old. Phase 1 (N = 48) consisted of item generation and expert (N = 5) review of items; Phase 2 (N = 179) involved item analyses; in Phase 3 (N = 496) exploratory factor analysis assessed the underlying structure; in Phase 4 (N = 405) confirmatory factor analyses resulted in a 25-item inventory with 5 subscales.

Effects of assimilable organic carbon and free chlorine on bacterial growth in drinking water.

PubMed

Liu, Xiaolu; Wang, Jingqi; Liu, Tingting; Kong, Weiwen; He, Xiaoqing; Jin, Yi; Zhang, Bolin

2015-01-01

Assimilable organic carbon (AOC) is one of the most important factors affecting the re-growth of microorganisms in drinking water. High AOC concentrations result in biological instability, but disinfection kills microbes to ensure the safety of drinking water. Free chlorine is an important oxidizing agent used during the disinfection process. Therefore, we explored the combined effects of AOC and free chlorine on bacterial growth in drinking water using flow cytometry (FCM). The initial AOC concentration was 168 μg.L(-1) in all water samples. Without free chlorine, the concentrations of intact bacteria increased but the level of AOC decreased. The addition of sodium hypochlorite caused an increase and fluctuation in AOC due to the oxidation of organic carbon. The concentrations of intact bacteria decreased from 1.1 × 10(5) cells.mL(-1) to 2.6 × 10(4) cells.mL(-1) at an initial free chlorine dose of 0.6 mg.L(-1) to 4.8 × 10(4) cells.mL(-1) at an initial free chlorine dose of 0.3 mg.L(-1) due to free chlorine originating from sodium hypochlorite. Additionally, free chlorine might be more obviously affected AOC concentrations than microbial growth did. These results suggested that AOC and free chlorine might have combined effects on microbial growth. In this study, our results showed concentrations determined by FCM were higher than those by HPC, which indicated that some E. coli detected by FCM might not be detected using HPC in drinking water. The level of free chlorine might restrain the consumption of AOC by inhibiting the growth of E. coli; on the other hand, chlorination might increase the level of AOC, thereby increase the potential for microbial growth in the drinking water network.

Prevalence and risk factors for wheezing and allergic diseases in preschool children: A perspective from the Mediterranean coast of Turkey.

PubMed

Bolat, E; Arikoglu, T; Sungur, M A; Batmaz, S B; Kuyucu, S

The aim of the present study was to determine the prevalence and risk factors of allergic diseases in preschool children from one of the biggest cities in the Mediterranean Region of Turkey. The study population included 396 preschool children attending to urban daycare centres in Mersin. In the first stage, a comprehensive standardised questionnaire modified from the International Study of Asthma and Allergies in Childhood (ISAAC) was employed. In the second stage, serum food and inhalant specific IgE, and skin tests were performed in 45 children with frequent wheezing and 28 children with no wheezing. The prevalence of ever wheezing, current wheezing, physician-diagnosed asthma, allergic rhinitis and eczema were 53% (210), 33.3% (132), 27.3% (108), 13.4% (53) and 8.3% (33), respectively. A family history of atopy (OR=2.5, 95% CI: 1.3-4.7, p=0.004), dampness at home (OR=2.4, 95% CI: 1.2-4.8, p=0.008), a history of intestinal parasites (OR=4.3, 95% CI: 1.7-10.9, p=0.002), previous history of pneumonia (OR=6.9, 95% CI: 1.9-25.9, p=0.004), initiation of complementary foods before the age of three months (OR=6.1, 95%CI: 1.4-26.9, p=0.02) and presence of food allergy (OR=3.1, 95% CI: 1.1-9.2, p=0.03) were found to be significant risk factors for physician-diagnosed asthma. The risk factors for frequent wheezing were maternal smoking during pregnancy (OR=5.2, 95% CI: 0.9-28.7, p=0.05) and high serum IgE levels (OR=2.9, 95% CI: 0.9-9.0, p=0.05) at borderline significance. Our study was the first epidemiological study in preschool children in the Mediterranean region of Turkey and demonstrated a high prevalence of asthma and allergic diseases, probably related to humid climatic properties in addition to other environmental and genetic factors. Copyright © 2017 SEICAP. Published by Elsevier España, S.L.U. All rights reserved.

F-16 Task Analysis Criterion-Referenced Objective and Objectives Hierarchy Report. Volume 4

DTIC Science & Technology

1981-03-01

Initiation cues: Engine flameout Systems presenting cues: Aircraft fuel, engine STANDARD: Authority: TACR 60-2 Performance precision: TD in first 1/3 of...task: None Initiation cues: On short final Systems preventing cues: N/A STANDARD: Authority: 60-2 Performance precision: +/- .5 AOA; TD zone 150-1000...precision: +/- .05 AOA; TD Zone 150-1000 Computational accuracy: N/A ... . . ... . ... e e m I TASK NO.: 1.9.4 BEHAVIOR: Perform short field landing

The initiation of homeless youth into the street economy.

PubMed

Gwadz, Marya Viorst; Gostnell, Karla; Smolenski, Carol; Willis, Brian; Nish, David; Nolan, Theresa C; Tharaken, Maya; Ritchie, Amanda S

2009-04-01

Homeless youth (HY) who lack employment in the formal economy typically turn to the street economy (e.g., prostitution, drug selling) for survival. Guided by the theory of social control, the present paper explores factors influencing HY's initiation into the street economy. Eighty HY (ages 15-23) were recruited from four community-based organizations. All participated in structured interviews and 25% participated in qualitative interviews. Almost all HY had participated in the street (81%) and formal economies (69%). Five main factors simultaneously influenced initiation into the street economy: social control/bonds, barriers to the formal economy (e.g., homelessness, educational deficits, mental health problems, incarceration, stigma), tangible and social/emotional benefits of the street economy, severe economic need, and the active recruitment of HY into the street economy by others. Qualitative and quantitative data sources were congruent. Intervention efforts are needed at multiple levels of influence to promote HY's success in the formal economy.

Antimicrobial resistance patterns, clinical features, and risk factors for septic shock and death of nosocomial E coli bacteremia in adult patients with hematological disease: A monocenter retrospective study in China.

PubMed

Ma, Jie; Li, Ning; Liu, Yajie; Wang, Chong; Liu, Xiaoyan; Chen, Shengmei; Xie, Xinsheng; Gan, Silin; Wang, Meng; Cao, Weijie; Wang, Fang; Liu, Yanfan; Wan, Dingming; Sun, Ling; Sun, Hui

2017-05-01

The aim of this retrospective analysis was to evaluate the antimicrobial resistance, clinical features, and risk factors for septic shock and death of nosocomial E coli bacteremia in adult patients in a single hematological center in China. A retrospective case-control study of 157 adult hematological patients with 168 episodes of E coli bacteremia was initiated from April 2012 to July 2015. Antimicrobial susceptibility as well as antimicrobial co-resistance rates were analyzed. Clinical features and outcomes were also studied. In addition, risk factors for septic shock and death were investigated. Among the 553 positive blood isolates during the study period, the prevalence of E coli was 33.3% and ESBL production strains represented 61.9% of those examined. In all the E coli strains isolated, 85.6% were multidrug-resistance (MDR), 2.4% were extensive drug resistance (XDR), and 6.0% were resistant to carbapenems. More MDR phenotype was noted in ESBL-EC strains (98.6% vs 62.8%, P<.001) and isolates from neutropenic patients (98.6% vs 62.8%, P < .001). In the antimicrobial susceptibility test, carbapenems and amikacin exhibited not only higher in vitro activity against E coli (94.0% and 92.0%, respectively), but lower co-resistance rates to other antibiotics. Carbapenem resistant strains retained full sensitivity to tigecycline and 60% to amikacin. Piperacillin/tazobatam was the third sensitive drug to both ESBL-EC (77.1%) and non-ESBL-EC (86.0%). In our series, 81.6% episodes received appropriate initial antibiotic treatment and no significant decrease in it was found in bacteremia due to ESBL E coli and patients with neutropenia, septic shock. Septic shock was noted in 15.5% patients and the overall 30-day mortality rate was 21.7%. Multivariate analysis revealed that induction chemotherapy (OR 2.126; 95% CI 1.624-11.332; P = .003) and polymicrobial infection (OR 3.628; 95% CI 1.065-21.219; P = .041) were risk factors for septic shock, whereas male (OR 2.223; 95% CI 1.132-12.022; P < .01) and septic shock (OR 52.359; 95% CI 19.951-292.690; P = .030) were risk factors for death.In the hematology department, ESBL-producing and MDR are widely prevalent in E coli bacteremia which is still a major life-threatening problem, especially for patients with septic shock. For empirical antimicrobial therapy, combination based on aminoglycoside, especially amikacin, will be helpful to increase the antimicrobial coverage against ESBL-EC while combining tigecycline with aminoglycoside should be considered for seriously carbapenem-resistant infectious patients.

The association between speed of transition from initiation to subsequent use of cannabis and later problematic cannabis use, abuse and dependence.

PubMed

Hines, Lindsey A; Morley, Katherine I; Strang, John; Agrawal, Arpana; Nelson, Elliot C; Statham, Dixie; Martin, Nicholas G; Lynskey, Michael T

2015-08-01

To test whether speed of transition from initiation use to subsequent use of cannabis is associated with likelihood of later cannabis dependence and other outcomes, and whether transition speed is attributable to genetic or environmental factors. Cross-sectional interview study. Australia. A total of 2239 twins and siblings who reported using cannabis at least twice [mean age at time of survey = 32.0, 95% confidence interval (CI) = 31.9 - 32.1, range = 22-45]. Time between initiation and subsequent cannabis use (within 1 week; within 3 months; between 3 and 12 months; more than 1 year later), later use of cannabis and symptoms of DSM-IV cannabis abuse/dependence. Multinomial regression analyses (comparison group: more than 1 year later) adjusted the association between speed of transition and the outcomes of cannabis daily use, abuse/dependence and treatment-seeking after controlling for socio-demographic, childhood, mental health, peer and licit drug factors. Twin modelling estimated the proportion of variance in transition speed attributable to genetic (A), common environment (C) and unique environmental (E) factors. Subsequent use of cannabis within 1 week of initiation was associated with daily use [odds ratio (OR) = 2.64, 95% CI = 1.75-3.99], abuse and/or dependence (OR = 3.25, 95% CI = 2.31-4.56) and treatment-seeking for cannabis problems (OR = 1.89, 95% CI = 1.03-3.46). Subsequent use within 3 months was associated with abuse and/or dependence (OR = 1.61, 95% CI = 1.18-2.19). The majority of the variation of the speed of transition was accounted for by unique environment factors (0.75). Rapid transition from initiation to subsequent use of cannabis is associated with increased likelihood of subsequent daily cannabis use and abuse/dependence. © 2015 Society for the Study of Addiction.

Self-Efficacy and Short-Term Adherence to Continuous Positive Airway Pressure Treatment in Children.

PubMed

Xanthopoulos, Melissa S; Kim, Ji Young; Blechner, Michael; Chang, Ming-Yu; Menello, Mary Kate; Brown, Christina; Matthews, Edward; Weaver, Terri E; Shults, Justine; Marcus, Carole L

2017-07-01

Infants, children, and adolescents are increasingly being prescribed continuous positive airway pressure (CPAP) for treatment of obstructive sleep apnea syndrome (OSAS), yet adherence is often poor. The purpose of this study was to examine the relationship between caregiver and patient-reported health cognitions about CPAP prior to starting CPAP and CPAP adherence at 1 month. We hypothesized that greater caregiver-reported self-efficacy would be positively associated with CPAP adherence in children. We also evaluated patient-reported self-efficacy and caregiver- and patient-reported risk perception and outcome expectations as they related to adherence, as well as how demographic factors influenced these relationships. A pediatric modification of the Self-Efficacy Measure for Sleep Apnea Questionnaire was administered to children and adolescents with OSAS-prescribed CPAP and their caregivers during the clinical CPAP-initiation visit. The primary outcome variable for adherence was the average total minutes of CPAP usage across all days from the date that CPAP was initiated to 31 days later. Unadjusted ordinary least-square regression showed a significant association between caregiver-reported self-efficacy and adherence (p = .007), indicating that mean daily CPAP usage increased by 48.4 minutes when caregiver-reported self-efficacy increased by one point (95% confidence interval 13.4-83.4 minutes). No other caregiver- or patient-reported cognitive health variables were related to CPAP use. This study indicates that caregiver CPAP-specific self-efficacy is an important factor to consider when starting youth on CPAP therapy for OSAS. Employing strategies to improve caregiver self-efficacy, beginning at CPAP initiation, may promote CPAP adherence. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

Beyond health information technology: critical factors necessary for effective diabetes disease management.

PubMed

Ciemins, Elizabeth L; Coon, Patricia J; Fowles, Jinnet Briggs; Min, Sung-joon

2009-05-01

Electronic health records (EHRs) have been implemented throughout the United States with varying degrees of success. Past EHR implementation experiences can inform health systems planning to initiate new or expand existing EHR systems. Key "critical success factors," e.g., use of disease registries, workflow integration, and real-time clinical guideline support, have been identified but not fully tested in practice. A pre/postintervention cohort analysis was conducted on 495 adult patients selected randomly from a diabetes registry and followed for 6 years. Two intervention phases were evaluated: a "low-dose" period targeting primary care provider (PCP) and patient education followed by a "high-dose" EHR diabetes management implementation period, including a diabetes disease registry and office workflow changes, e.g., diabetes patient preidentification to facilitate real-time diabetes preventive care, disease management, and patient education. Across baseline, "low-dose," and "high-dose" postintervention periods, a significantly greater proportion of patients (a) achieved American Diabetes Association (ADA) guidelines for control of blood pressure (26.9 to 33.1 to 43.9%), glycosylated hemoglobin (48.5 to 57.5 to 66.8%), and low-density lipoprotein cholesterol (33.1 to 44.4 to 56.6%) and (b) received recommended preventive eye (26.2 to 36.4 to 58%), foot (23.4 to 40.3 to 66.9%), and renal (38.5 to 53.9 to 71%) examinations or screens. Implementation of a fully functional, specialized EHR combined with tailored office workflow process changes was associated with increased adherence to ADA guidelines, including risk factor control, by PCPs and their patients with diabetes. Incorporation of previously identified "critical success factors" potentially contributed to the success of the program, as did use of a two-phase approach. 2009 Diabetes Technology Society.

[Risk of arrhythmia and domestic low-voltage electrical injury].

PubMed

Claudet, I; Maréchal, C; Debuisson, C; Salanne, S

2010-04-01

Analysis of domestic low-voltage (220-240 V) electrical injury in children admitted to a pediatric emergency department to illustrate the low risk of initial or delayed risk of arrhythmia. Retrospective study between 2001 and 2008 analyzing all children aged less than 15 years admitted for a low-voltage electrical injury. The data collected were age, sex, time and circumstances of the accident, time and day of admission, transport modalities, presence of risk factors for arrhythmia (transthoracic current, wet skin, tetany, loss of consciousness or neurological symptoms, and initial EKG abnormalities), injuries, EKG, muscular and/or cardiac enzyme values, progression and complications. For statistical analysis, data were entered in Microsoft Excel tables. Analysis was done with StatView5.1 (SAS Institute) and Epi Info 6.04fr (VF, ENSP epiconcept). In the descriptive analysis, the data are presented as mean values with SD, median and range. Forty-eight children were included. The mean annual number of admissions was equal to 6 (range, 3-12). The mean age was 6.2 + or - 4.3 years (median, 4.6 years). There was a male predominance: the overall sex ratio was 1.5, i.e., 3 before the age of 2 and 2.6 before the age of 10. The electrical injury occurred after contact with a wire or a connected cord or after the introduction of a metallic object in a wall socket. Ten children had risk factors of arrhythmia (mainly wet skin or thoracic pain). Twenty-nine children suffered from burns to the extremities (digits and hands, 70 %). At admission, 45 children had an EKG performed. The initial EKG was considered abnormal in 8 cases showing: sinusal tachycardia (n=4), incomplete right bundle branch block (n=4), and V(1) negative T waves (n=1). The EKG normalized within the first 12h. Hospitalization for cardiac monitoring was required for 18 children. No delayed arrhythmia occurred. In a mean time of 3.5h after the accident, a troponin dosage was given to 15 children and was normal in all cases. One child developed rhabdomyolysis and evolved without needing dialysis. After a low-voltage electrical injury, initial arrhythmia is not frequent, with often a nonspecific and transitory EKG expression; delayed arrhythmia is very rare. Children presenting to the emergency department after such an electrical accident, who are asymptomatic, without any risk factors for arrhythmia (wet skin, tetany, vertical pathway of the current, preexistent cardiological conditions, loss of consciousness) and with a normal initial EKG do not require cardiac monitoring. Copyright 2010 Elsevier Masson SAS. All rights reserved.

Oral Language and Listening Comprehension: Same or Different Constructs?

PubMed

2017-05-24

The purpose of this study was to add to our understanding of the dimensionality of oral language in children and to determine whether oral language and listening comprehension are separate constructs in children enrolled in preschool (PK) through 3rd grade. In the spring of the school year, children from 4 states (N = 1,869) completed multiple measures of oral language (i.e., expressive and receptive vocabulary and grammar) and listening comprehension as part of a larger study of the language bases of reading comprehension. Initial confirmatory factor analysis found evidence that measures of oral language and listening comprehension loaded on two separate factors in PK through 3rd grade; however, these factors were highly correlated at all grades. These results suggest that oral language and listening comprehension are best characterized as a single oral language construct in PK through 3rd grade. The implications for early identification and intervention are discussed.

Being "slow to see" is a dynamic visual function consequence of infantile nystagmus syndrome: model predictions and patient data identify stimulus timing as its cause.

PubMed

Wang, Z I; Dell'Osso, L F

2007-05-01

The objective of this study was to investigate the dynamic properties of infantile nystagmus syndrome (INS) that affect visual function; i.e., which factors influence latency of the initial reflexive saccade (Ls) and latency to target acquisition (Lt). We used our behavioral ocular motor system (OMS) model to simulate saccadic responses (in the presence of INS) to target jumps at different times within a single INS cycle and at random times during multiple cycles. We then studied the responses of 4 INS subjects with different waveforms to test the model's predictions. Infrared reflection was used for 1 INS subject, high-speed digital video for 3. We recorded and analyzed human responses to large and small target-step stimuli. We evaluated the following factors: stimulus time within the cycle (Tc), normalized Tc (Tc%), initial orbital position (Po), saccade amplitude, initial retinal error (e(i)), and final retinal error (e(f)). The ocular motor simulations were performed in MATLAB Simulink environment and the analysis was performed in MATLAB environment using OMLAB software. Both the OMS model and OMtools software are available from http://http:www.omlab.org. Our data analysis showed that for each subject, Ls was a fixed value that is typically higher than the normal saccadic latency. Although saccadic latency appears somewhat lengthened in INS, the amount is insufficient to cause the "slow-to-see" impression. For Lt, Tc% was the most influential factor for each waveform type. The main refixation strategies employed by INS subjects made use of slow and fast phases and catch-up saccades, or combinations of them. These strategies helped the subjects to foveate effectively after target movement, sometimes at the cost of increased target acquisition time. Foveating or braking saccades intrinsic to the nystagmus waveforms seemed to disrupt the OMS' ability to accurately calculate reflexive saccades' amplitude and refoveate. Our OMS model simulations demonstrated this emergent behavior and predicted the lengthy target acquisition times found in the patient data.

Initial Gut Microbial Composition as a Key Factor Driving Host Response to Antibiotic Treatment, as Exemplified by the Presence or Absence of Commensal Escherichia coli

PubMed Central

Ju, Tingting; Shoblak, Yasmeen; Gao, Yanhua; Yang, Kaiyuan; Fouhse, Janelle; Finlay, B. Brett; So, Yee Wing; Stothard, Paul

2017-01-01

ABSTRACT Antibiotics are important for treating bacterial infection; however, efficacies and side effects of antibiotics vary in medicine and experimental models. A few studies have correlated microbiota composition variations with health outcomes in response to antibiotics; however, no study has demonstrated causality. We had noted variation in colonic expression of C-type lectins, regenerating islet-derived protein 3β (Reg3β) and Reg3γ, after metronidazole treatment in a mouse model. To investigate the effects of specific variations in the preexisting microbiome on host response to antibiotics, mice harboring a normal microbiota were allocated to 4 treatments in a 2-by-2 factorial arrangement with or without commensal Escherichia coli and with or without metronidazole in drinking water. E. coli colonized readily without causing a notable shift in the microbiota or host response. Metronidazole administration reduced microbiota biodiversity, indicated by decreased Chao1 and Shannon index values, and altered microbiota composition. However, the presence of E. coli strongly affected metronidazole-induced microbiota shifts. Remarkably, this single commensal bacterium in the context of a complex population led to variations in host responses to metronidazole treatment, including increased expression of antimicrobial peptides Reg3β and Reg3γ and intestinal inflammation indicated by tumor necrosis factor alpha levels. Similar results were obtained from 2-week antibiotic exposure and with additional E. coli isolates. The results of this proof-of-concept study indicate that even minor variations in initial commensal microbiota can drive shifts in microbial composition and host response after antibiotic administration. As well as providing an explanation for variability in animal models using antibiotics, the findings encourage the development of personalized medication in antibiotic therapies. IMPORTANCE This work provides an understanding of variability in studies where antibiotics are used to alter the gut microbiota to generate a host response. Furthermore, although providing evidence only for the one antibiotic, the study demonstrated that initial gut microbial composition is a key factor driving host response to antibiotic administration, creating a compelling argument for considering personalized medication based on individual variations in gut microbiota. PMID:28667114

Initial Gut Microbial Composition as a Key Factor Driving Host Response to Antibiotic Treatment, as Exemplified by the Presence or Absence of Commensal Escherichia coli.

PubMed

Ju, Tingting; Shoblak, Yasmeen; Gao, Yanhua; Yang, Kaiyuan; Fouhse, Janelle; Finlay, B Brett; So, Yee Wing; Stothard, Paul; Willing, Benjamin P

2017-09-01

Antibiotics are important for treating bacterial infection; however, efficacies and side effects of antibiotics vary in medicine and experimental models. A few studies have correlated microbiota composition variations with health outcomes in response to antibiotics; however, no study has demonstrated causality. We had noted variation in colonic expression of C-type lectins, regenerating islet-derived protein 3β (Reg3β) and Reg3γ, after metronidazole treatment in a mouse model. To investigate the effects of specific variations in the preexisting microbiome on host response to antibiotics, mice harboring a normal microbiota were allocated to 4 treatments in a 2-by-2 factorial arrangement with or without commensal Escherichia coli and with or without metronidazole in drinking water. E. coli colonized readily without causing a notable shift in the microbiota or host response. Metronidazole administration reduced microbiota biodiversity, indicated by decreased Chao1 and Shannon index values, and altered microbiota composition. However, the presence of E. coli strongly affected metronidazole-induced microbiota shifts. Remarkably, this single commensal bacterium in the context of a complex population led to variations in host responses to metronidazole treatment, including increased expression of antimicrobial peptides Reg3β and Reg3γ and intestinal inflammation indicated by tumor necrosis factor alpha levels. Similar results were obtained from 2-week antibiotic exposure and with additional E. coli isolates. The results of this proof-of-concept study indicate that even minor variations in initial commensal microbiota can drive shifts in microbial composition and host response after antibiotic administration. As well as providing an explanation for variability in animal models using antibiotics, the findings encourage the development of personalized medication in antibiotic therapies. IMPORTANCE This work provides an understanding of variability in studies where antibiotics are used to alter the gut microbiota to generate a host response. Furthermore, although providing evidence only for the one antibiotic, the study demonstrated that initial gut microbial composition is a key factor driving host response to antibiotic administration, creating a compelling argument for considering personalized medication based on individual variations in gut microbiota. Copyright © 2017 American Society for Microbiology.

Identification of residues within the African swine fever virus DP71L protein required for dephosphorylation of translation initiation factor eIF2α and inhibiting activation of pro-apoptotic CHOP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barber, Claire; Netherton, Chris; Goatley, Lynnett

The African swine fever virus DP71L protein recruits protein phosphatase 1 (PP1) to dephosphorylate the translation initiation factor 2α (eIF2α) and avoid shut-off of global protein synthesis and downstream activation of the pro-apoptotic factor CHOP. Residues V16 and F18A were critical for binding of DP71L to PP1. Mutation of this PP1 binding motif or deletion of residues between 52 and 66 reduced the ability of DP71L to cause dephosphorylation of eIF2α and inhibit CHOP induction. The residues LSAVL, between 57 and 61, were also required. PP1 was co-precipitated with wild type DP71L and the mutant lacking residues 52- 66 ormore » the LSAVL motif, but not with the PP1 binding motif mutant. The residues in the LSAVL motif play a critical role in DP71L function but do not interfere with binding to PP1. Instead we propose these residues are important for DP71L binding to eIF2α. - Highlights: •The African swine fever virus DP71L protein recruits protein phosphatase 1 (PP1) to dephosphorylate translation initiation factor eIF2α (eIF2α). •The residues V{sup 16}, F{sup 18} of DP71L are required for binding to the α, β and γ isoforms of PP1 and for DP71L function. •The sequence LSAVL downstream from the PP1 binding site (residues 57–61) are also important for DP71L function. •DP71L mutants of the LSAVL sequence retain ability to co-precipitate with PP1 showing these sequences have a different role to PP1 binding.« less

Behavior of inactivation kinetics of Escherichia coli by dense phase carbon dioxide.

PubMed

Liao, Hongmei; Zhang, Yan; Hu, Xiaosong; Liao, Xiaojun; Wu, Jihong

2008-08-15

Inactivation of Escherichia coli in cloudy apple juice by dense phase carbon dioxide (DPCD) was investigated. The pressures were 10, 20 and 30 MPa, the temperatures were 32, 37 and 42 degrees C. The inactivation kinetic behavior of E. coli conformed to a sigmoid curve with a shoulder and a tail, which was closely related with temperature or pressure. With the increase of temperature or pressure, the shoulder became unclear or even disappeared. The experimental data were well fitted to a model proposed by Xiong et al. [Xiong, R., Xie, G., Edmondson, A.E., Sheard, M.A., 1999. A mathematical model for bacterial inactivation. International Journal of Food Microbiology 46, 45-55], the kinetic parameters of t(lag) (the lag time length), f (the initial proportion of less resistant population), k(1) (the inactivation rate constant of less resistant fraction) and k(2) (the inactivation rate constant of resistant fraction), and t(4)(-)(D) (the time required for an 4-log-cycle reduction of bacteria under a given condition) were obtained from this model. The t(lag) declined from 4.032 to 0.890 min and t(4)(-)(D) from 54.955 to 18.840 min, k(1) was 1.74-4.4 times of k(2). Moreover, the model was validated by more experimental data, the accuracy factor (Af), bias factor (Bf), root mean square error (RMSE), sum of squares (SS), and correlation coefficient (R(2)) were used to evaluate this model performance, indicating that the model could provide a good fitting to the experimental data.

Improving the prognosis of patients with severely decreased glomerular filtration rate (CKD G4+): conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

PubMed Central

Eckardt, Kai-Uwe; Bansal, Nisha; Coresh, Josef; Evans, Marie; Grams, Morgan E.; Herzog, Charles A.; James, Matthew T.; Heerspink, Hiddo J.L.; Pollock, Carol A.; Stevens, Paul E.; Tamura, Manjula Kurella; Tonelli, Marcello A.; Wheeler, David C.; Winkelmayer, Wolfgang C.; Cheung, Michael; Hemmelgarn, Brenda R.

2018-01-01

Patients with severely decreased glomerular filtration rate (GFR) (i.e., chronic kidney disease [CKD] G4+) are at increased risk for kidney failure, cardiovascular disease (CVD) events (including heart failure), and death. However, little is known about the variability of outcomes and optimal therapeutic strategies, including initiation of kidney replacement therapy (KRT). Kidney Disease: Improving Global Outcomes (KDIGO) organized a Controversies Conference with an international expert group in December 2016 to address this gap in knowledge. In collaboration with the CKD Prognosis Consortium (CKD-PC) a global meta-analysis of cohort studies (n = 264,515 individuals with CKD G4+) was conducted to better understand the timing of clinical outcomes in patients with CKD G4+ and risk factors for different outcomes. The results confirmed the prognostic value of traditional CVD risk factors in individuals with severely decreased GFR, although the risk estimates vary for kidney and CVD outcomes. A 2- and 4-year model of the probability and timing of kidney failure requiring KRT was also developed. The implications of these findings for patient management were discussed in the context of published evidence under 4 key themes: management of CKD G4+, diagnostic and therapeutic challenges of heart failure, shared decision-making, and optimization of clinical trials in CKD G4+ patients. Participants concluded that variable prognosis of patients with advanced CKD mandates individualized, risk-based management, factoring in competing risks and patient preferences. PMID:29656903

Factors associated with operative treatment of enthesopathy of the extensor carpi radialis brevis origin.

PubMed

Kachooei, Amir Reza; Talaei-Khoei, Mojtaba; Faghfouri, Aram; Ring, David

2016-04-01

This study investigated the factors associated with variation in the rate of surgery for enthesopathy of the extensor carpi radialis brevis (eECRB). We used a large database from 3 academic hospitals including 5964 patients with the diagnosis of eECRB from 2001 to 2007. Of those, 244 patients (4%) had surgery for eECRB. We used the date of the first encounter as the date of diagnosis. We also recorded the date of the first cortisone injection and surgery for eECRB. We used Cox multivariable regression analysis to find factors associated with surgery. We considered the following explanatory factors: age, sex, race, diabetes, a diagnosis of major depression, a diagnosis of an anxiety disorder, hospital, provider (surgeon vs. nonsurgeon), corticosteroid injection, and the time from diagnosis to the first cortisone injection. The hazard ratio of having surgery was 12-times greater if the initial provider was an orthopedic surgeon rather a nonsurgeon and 1.7-times greater at 1 of the 2 hospitals. The rate of surgery varied substantially, ranging from 0% to 22%. Corticosteroid injection delayed the time to surgery but was ultimately associated with a higher rate of surgery. The majority (86%) of surgeries were done within 1 year of the first documented office visit. It seems likely that an emphasis on the preferences and values of the patient rather than the surgeon would decrease the variation in surgery rates for eECRB observed in this study. Methods for optimizing the influence of patient preferences and values on decision making (eg, decision aids) merit additional study. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Cultural and Environmental Factors Affecting the Longevity of Escherichia coli in Histosols †

PubMed Central

Tate, Robert L.

1978-01-01

The survival of Escherichia coli in organic soils (Histosols) was examined. The death rate of this organism in Pahokee muck was less than that observed in Pompano fine sand. The number of viable E. coli cells found in the muck was approximately threefold greater than that found in the sand following 8 days of incubation. The initial population of the coliform affected the death rate. The rate of loss of viability varied 100-fold when the population size decreased from 2.5 × 107 to 3.4 × 104. Other factors affecting the viability of E. coli in muck were aerobic versus anaerobic growth of the organism and moist versus flooded conditions in the soil. The greatest survival of the coliform was noted with anaerobically grown cells amended to flooded soil. That the observed decrease in E. coli viability in soil was the result of biotic factors was demonstrated with amendment of sterile soil with E. coli. When 1.1 × 105 bacteria per g of soil were added to sterile muck, a population of 3.0 × 107 organisms per g of soil developed over a 10-day period. The role of the protozoa in eradication of the coliform from the muck was indicated by a sixfold increase in the protozoan population in natural soil amended with E. coli. Higher organic matter content in a Histosol compared with a mineral soil resulted in an increased survival of the fecal coliforms. Biotic factors are instrumental in the decline in coliform populations, but the potential for growth of the coliform in the organic soil could extend the survival of the organism. PMID:350158

Correlates of adherence to a telephone-based multiple health behavior change cancer preventive intervention for teens: the Healthy for Life Program (HELP).

PubMed

Mays, Darren; Peshkin, Beth N; Sharff, McKane E; Walker, Leslie R; Abraham, Anisha A; Hawkins, Kirsten B; Tercyak, Kenneth P

2012-02-01

This study examined factors associated with teens' adherence to a multiple health behavior cancer preventive intervention. Analyses identified predictors of trial enrollment, run-in completion, and adherence (intervention initiation, number of sessions completed). Of 104 teens screened, 73% (n = 76) were trial eligible. White teens were more likely to enroll than non-Whites (χ(2)[1] df = 4.49, p = .04). Among enrolled teens, 76% (n = 50) completed the run-in; there were no differences between run-in completers and noncompleters. A majority of run-in completers (70%, n = 35) initiated the intervention, though teens who initiated the intervention were significantly younger than those who did not (p < .05). The mean number of sessions completed was 5.7 (SD = 2.6; maximum = 8). After adjusting for age, teens with poorer session engagement (e.g., less cooperative) completed fewer sessions (B = -1.97, p = .003, R (2) = .24). Implications for adolescent cancer prevention research are discussed.

Class I and II Small Heat Shock Proteins Together with HSP101 Protect Protein Translation Factors during Heat Stress1[OPEN

PubMed Central

Basha, Eman; Fowler, Mary E.; Kim, Minsoo; Bordowitz, Juliana; Katiyar-Agarwal, Surekha

2016-01-01

The ubiquitous small heat shock proteins (sHSPs) are well documented to act in vitro as molecular chaperones to prevent the irreversible aggregation of heat-sensitive proteins. However, the in vivo activities of sHSPs remain unclear. To investigate the two most abundant classes of plant cytosolic sHSPs (class I [CI] and class II [CII]), RNA interference (RNAi) and overexpression lines were created in Arabidopsis (Arabidopsis thaliana) and shown to have reduced and enhanced tolerance, respectively, to extreme heat stress. Affinity purification of CI and CII sHSPs from heat-stressed seedlings recovered eukaryotic translation elongation factor (eEF) 1B (α-, β-, and γ-subunits) and eukaryotic translation initiation factor 4A (three isoforms), although the association with CI sHSPs was stronger and additional proteins involved in translation were recovered with CI sHSPs. eEF1B subunits became partially insoluble during heat stress and, in the CI and CII RNAi lines, showed reduced recovery to the soluble cell fraction after heat stress, which was also dependent on HSP101. Furthermore, after heat stress, CI sHSPs showed increased retention in the insoluble fraction in the CII RNAi line and vice versa. Immunolocalization revealed that both CI and CII sHSPs were present in cytosolic foci, some of which colocalized with HSP101 and with eEF1Bγ and eEF1Bβ. Thus, CI and CII sHSPs have both unique and overlapping functions and act either directly or indirectly to protect specific translation factors in cytosolic stress granules. PMID:27474115

Epidemiology of tobacco use and dependence.

PubMed

Giovino, G A; Henningfield, J E; Tomar, S L; Escobedo, L G; Slade, J

1995-01-01

Knowledge of the epidemiology of tobacco use and dependence can be used to guide research initiatives, intervention programs, and policy decisions. Both the reduction in the prevalence of smoking among US adults and black adolescents and the decline in per capita consumption are encouraging. These changes have probably been influenced by factors operating at the individual (e.g., school-based prevention programs and cessation programs) and environmental (e.g., mass media educational strategies, the presence of smoke-free laws and policies, and the price of tobacco products) levels (for a discussion of these factors, see, e.g., refs. 2, 48, 52, 183, and 184). The lack of progress among adolescents, especially whites and males, and the high risk for experimenters of developing tobacco dependence present cause for great concern (48, 183-186). In addition to those discussed above, several areas of research can be recommended. 1. Better understanding of the clustering of tobacco use with the use of other drugs, other risk behaviors, and other psychiatric disorders could better illuminate the causal processes involved, as well as the special features of the interventions needed to prevent and treat tobacco dependence. 2. To better understand population needs, trend analyses of prevalence, initiation, and cessation should, whenever possible, incorporate standardized measures of these other risk factors. Future research should compare the effect of socioeconomic status variables on measures of smoking behavior among racial/ethnic groups in the United States. 3. For reasons that may be genetic, environmental, or both, some persons do not progress beyond initial experimentation with tobacco use (2, 48, 183, 187-192), but about one-third to one-half of those who experiment with cigarettes become regular users (48, 193, 194). Factors, both individual and environmental, that can influence the susceptibility of individuals to tobacco dependence need further attention. 4. To estimate their sensitivity and specificity, comparisons of the National Household Survey on Drug Abuse indicators of dependence with DSM-based criteria are needed. Public health action continues to be warranted to reduce the substantial morbidity and mortality caused by tobacco use (195). A paradigm for such action has been recommended and involves preventing the onset of use, treating tobacco dependence, protecting non-smokers from exposure to secondhand smoke, promoting nonsmoking messages while limiting the effect of tobacco advertising and promotion on young people, increasing the real (inflation-adjusted) price of tobacco products, and regulating tobacco products (186).

Vascular Endothelial Growth Factor (VEGF) and Platelet (PF-4) Factor 4 Inputs Modulate Human Microvascular Endothelial Signaling in a Three-Dimensional Matrix Migration Context*

PubMed Central

Hang, Ta-Chun; Tedford, Nathan C.; Reddy, Raven J.; Rimchala, Tharathorn; Wells, Alan; White, Forest M.; Kamm, Roger D.; Lauffenburger, Douglas A.

2013-01-01

The process of angiogenesis is under complex regulation in adult organisms, particularly as it often occurs in an inflammatory post-wound environment. As such, there are many impacting factors that will regulate the generation of new blood vessels which include not only pro-angiogenic growth factors such as vascular endothelial growth factor, but also angiostatic factors. During initial postwound hemostasis, a large initial bolus of platelet factor 4 is released into localized areas of damage before progression of wound healing toward tissue homeostasis. Because of its early presence and high concentration, the angiostatic chemokine platelet factor 4, which can induce endothelial anoikis, can strongly affect angiogenesis. In our work, we explored signaling crosstalk interactions between vascular endothelial growth factor and platelet factor 4 using phosphotyrosine-enriched mass spectrometry methods on human dermal microvascular endothelial cells cultured under conditions facilitating migratory sprouting into collagen gel matrices. We developed new methods to enable mass spectrometry-based phosphorylation analysis of primary cells cultured on collagen gels, and quantified signaling pathways over the first 48 h of treatment with vascular endothelial growth factor in the presence or absence of platelet factor 4. By observing early and late signaling dynamics in tandem with correlation network modeling, we found that platelet factor 4 has significant crosstalk with vascular endothelial growth factor by modulating cell migration and polarization pathways, centered around P38α MAPK, Src family kinases Fyn and Lyn, along with FAK. Interestingly, we found EphA2 correlational topology to strongly involve key migration-related signaling nodes after introduction of platelet factor 4, indicating an influence of the angiostatic factor on this ambiguous but generally angiogenic signal in this complex environment. PMID:24023389

Influence of multiple scattering on CloudSat measurements in snow: A model study

NASA Astrophysics Data System (ADS)

Matrosov, Sergey Y.; Battaglia, Alessandro

2009-06-01

The effects of multiple scattering on larger precipitating hydrometers have an influence on measurements of the spaceborne W-band (94 GHz) CloudSat radar. This study presents initial quantitative estimates of these effects in “dry” snow using radiative transfer calculations for appropriate snowfall models. It is shown that these effects become significant (i.e., greater than approximately 1 dB) when snowfall radar reflectivity factors are greater than about 10-15 dBZ. Reflectivity enhancement due to multiple scattering can reach 4-5 dB in heavier stratiform snowfalls. Multiple scattering effects counteract signal attenuation, so the observed CloudSat reflectivity factors in snowfall could be relatively close to the values that would be observed in the case of single scattering and the absence of attenuation.

Neuronal pentraxin 1: A synaptic-derived plasma biomarker in Alzheimer's disease.

PubMed

Ma, Qiu-Lan; Teng, Edmond; Zuo, Xiaohong; Jones, Mychica; Teter, Bruce; Zhao, Evan Y; Zhu, Cansheng; Bilousova, Tina; Gylys, Karen H; Apostolova, Liana G; LaDu, Mary Jo; Hossain, Mir Ahamed; Frautschy, Sally A; Cole, Gregory M

2018-06-01

Synaptic neurodegeneration is thought to be an early event initiated by soluble β-amyloid (Aβ) aggregates that closely correlates with cognitive decline in Alzheimer disease (AD). Apolipoprotein ε4 (APOE4) is the most common genetic risk factor for both familial AD (FAD) and sporadic AD; it accelerates Aβ aggregation and selectively impairs glutamate receptor function and synaptic plasticity. However, its molecular mechanisms remain elusive and these synaptic deficits are difficult to monitor. AD- and APOE4-dependent plasma biomarkers have been proposed, but synapse-related plasma biomarkers are lacking. We evaluated neuronal pentraxin 1 (NP1), a potential CNS-derived plasma biomarker of excitatory synaptic pathology. NP1 is preferentially expressed in brain and involved in glutamate receptor internalization. NP1 is secreted presynaptically induced by Aβ oligomers, and implicated in excitatory synaptic and mitochondrial deficits. Levels of NP1 and its fragments were increased in a correlated fashion in both brain and plasma of 7-8 month-old E4FAD mice relative to E3FAD mice. NP1 was also found in exosome preparations and reduced by dietary DHA supplementation. Plasma NP1 was higher in E4FAD+ (APOE4 +/+ /FAD +/- ) relative to E4FAD- (non-carrier; APOE4 +/+ /FAD -/- ) mice, suggesting NP1 is modulated by Aβ expression. Finally, relative to normal elderly, plasma NP1 was also elevated in patients with mild cognitive impairment (MCI) and elevated further in the subset who progressed to early-stage AD. In those patients, there was a trend towards increased NP1 levels in APOE4 carriers relative to non-carriers. These findings indicate that NP1 may represent a potential synapse-derived plasma biomarker relevant to early alterations in excitatory synapses in MCI and early-stage AD. Copyright © 2018. Published by Elsevier Inc.

3′ Cap-Independent Translation Enhancers of Plant Viruses

PubMed Central

Simon, Anne E.; Miller, W. Allen

2014-01-01

In the absence of a 5′ cap, plant positive-strand RNA viruses have evolved a number of different elements in their 3′ untranslated region (UTR) to attract initiation factors and/or ribosomes to their templates. These 3′ cap-independent translational enhancers (3′ CITEs) take different forms, such as I-shaped, Y-shaped, T-shaped, or pseudoknotted structures, or radiate multiple helices from a central hub. Common features of most 3′ CITEs include the ability to bind a component of the translation initiation factor eIF4F complex and to engage in an RNA-RNA kissing-loop interaction with a hairpin loop located at the 5′ end of the RNA. The two T-shaped structures can bind to ribosomes and ribosomal subunits, with one structure also able to engage in a simultaneous long-distance RNA-RNA interaction. Several of these 3′ CITEs are interchangeable and there is evidence that natural recombination allows exchange of modular CITE units, which may overcome genetic resistance or extend the virus’s host range. PMID:23682606

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murooka, Thomas T.; Rahbar, Ramtin; Department of Immunology, University of Toronto, Ont.

The proliferative capacity of cancer cells is regulated by factors intrinsic to cancer cells and by secreted factors in the microenvironment. Here, we investigated the proto-oncogenic potential of the chemokine receptor, CCR5, in MCF-7 breast cancer cell lines. At physiological levels, CCL5, a ligand for CCR5, enhanced MCF-7.CCR5 proliferation. Treatment with the mTOR inhibitor, rapamycin, inhibited this CCL5-inducible proliferation. Because mTOR directly modulates mRNA translation, we investigated whether CCL5 activation of CCR5 leads to increased translation. CCL5 induced the formation of the eIF4F translation initiation complex through an mTOR-dependent process. Indeed, CCL5 initiated mRNA translation, shown by an increase inmore » high-molecular-weight polysomes. Specifically, we show that CCL5 mediated a rapid up-regulation of protein expression for cyclin D1, c-Myc and Dad-1, without affecting their mRNA levels. Taken together, we describe a mechanism by which CCL5 influences translation of rapamycin-sensitive mRNAs, thereby providing CCR5-positive breast cancer cells with a proliferative advantage.« less

Development of alcohol expectancies and early alcohol use in children and adolescents: A systematic review.

PubMed

Smit, Koen; Voogt, Carmen; Hiemstra, Marieke; Kleinjan, Marloes; Otten, Roy; Kuntsche, Emmanuel

2018-03-01

Developmental changes in alcohol expectancies (AE) have been proposed to lead to alcohol use initiation and later alcohol use in adolescence. This systematic review aims to provide longitudinal evidence of the development of AE and the relation of AE to alcohol outcomes from childhood to late adolescence (4-18 years old). A computer-assisted search of relevant articles identified 1602 studies, of which 43 studies (conducted between 1996 and 2016) were selected. First, negative AE decline and positive AE increase in early adolescence. Moreover, alcohol use (initiation) seems to strongly influence changes in AE. Second, AE predict alcohol use initiation and drinking patterns over time. Third, longitudinal predictors of AE could be divided into individual predictors (i.e., alcohol-related cognitions, psychopathology, and genetics) and environmental predictors (i.e., family, peer, and media influences). Lastly, the results indicated that AE function as mediators of the relations between the various individual and environmental predictors and adolescent's alcohol use. Alcohol expectancies form an important framework through which drinking behavior can be explained over time. Due to the diverse findings on the predictors of AE, future longitudinal studies should further clarify the factors that are essential in the development of AE and adolescent's later alcohol use. Copyright © 2018 Elsevier Ltd. All rights reserved.

Hepatitis-C-virus-like internal ribosome entry sites displace eIF3 to gain access to the 40S subunit

NASA Astrophysics Data System (ADS)

Hashem, Yaser; Des Georges, Amedee; Dhote, Vidya; Langlois, Robert; Liao, Hstau Y.; Grassucci, Robert A.; Pestova, Tatyana V.; Hellen, Christopher U. T.; Frank, Joachim

2013-11-01

Hepatitis C virus (HCV) and classical swine fever virus (CSFV) messenger RNAs contain related (HCV-like) internal ribosome entry sites (IRESs) that promote 5'-end independent initiation of translation, requiring only a subset of the eukaryotic initiation factors (eIFs) needed for canonical initiation on cellular mRNAs. Initiation on HCV-like IRESs relies on their specific interaction with the 40S subunit, which places the initiation codon into the P site, where it directly base-pairs with eIF2-bound initiator methionyl transfer RNA to form a 48S initiation complex. However, all HCV-like IRESs also specifically interact with eIF3 (refs 2, 5, 6, 7, 9, 10, 11, 12), but the role of this interaction in IRES-mediated initiation has remained unknown. During canonical initiation, eIF3 binds to the 40S subunit as a component of the 43S pre-initiation complex, and comparison of the ribosomal positions of eIF3 and the HCV IRES revealed that they overlap, so that their rearrangement would be required for formation of ribosomal complexes containing both components. Here we present a cryo-electron microscopy reconstruction of a 40S ribosomal complex containing eIF3 and the CSFV IRES. Remarkably, although the position and interactions of the CSFV IRES with the 40S subunit in this complex are similar to those of the HCV IRES in the 40S-IRES binary complex, eIF3 is completely displaced from its ribosomal position in the 43S complex, and instead interacts through its ribosome-binding surface exclusively with the apical region of domain III of the IRES. Our results suggest a role for the specific interaction of HCV-like IRESs with eIF3 in preventing ribosomal association of eIF3, which could serve two purposes: relieving the competition between the IRES and eIF3 for a common binding site on the 40S subunit, and reducing formation of 43S complexes, thereby favouring translation of viral mRNAs.

Socio-Cultural Factors Associated with the Initiation of Opium Use in Darab, Iran

ERIC Educational Resources Information Center

Jafari, Siavash; Movaghar, Afarin Rahimi; Craib, Kevin; Baharlou, Souzan; Mathias, Richard

2009-01-01

This study aimed to identify socio-cultural factors facilitating initiation of opium use among drug users in Darab, Iran. A qualitative study using in-depth interviews was conducted. The study began in June 2006 and included 76 drug users, aged 20-43, of whom 95% (72) were male, and 5% (4) were female. The five most common factors facilitating…

Gender Differences in Use and Expectancies of E-Cigarettes: Online Survey Results

PubMed Central

Piñeiro, Bárbara; Correa, John B.; Simmons, Vani N.; Harrell, Paul T.; Menzie, Nicole S.; Unrod, Marina; Meltzer, Lauren R.; Brandon, Thomas H.

2015-01-01

Introduction Given the rapid increase in e-cigarette use, it is important to understand factors that may contribute to their initiation and maintenance. Because gender differences in tobacco use, product preferences, and expectancies are well established, similar gender differences may exist with e-cigarettes. The aim of this study was to identify gender differences among e-cigarette users in patterns of use, reasons for initiation and maintenance, and outcome expectancies regarding e-cigarettes. Methods Participants (N = 1815) completed an online survey from August through November, 2013. We assessed sociodemographics, smoking and e-cigarette history and use, and expectancies about e-cigarettes. Results We found gender differences in type of e-cigarette used, flavors used, nicotine dosage, source of information about e-cigarettes, place of purchase, and use of e-cigarettes where smoking is prohibited. In addition, males were more likely to report initiating e-cigarette use to quit smoking due to health concerns, whereas females were more likely to report initiation based on recommendations from family and friends. Males reported higher attributions for maintenance of e-cigarette use related to positive reinforcement (enjoyment), whereas females reported higher negative reinforcement attributions (stress reduction or mood management). Males reported more positive expectancies about e-cigarettes, including taste, social facilitation, and energy, whereas women rated e-cigarettes higher for weight control. Males also reported greater addiction-related e-cigarette expectancy than females. Conclusions Many of the gender differences with e-cigarettes parallel those previously found with traditional cigarette smoking. Although effect sizes associated with these differences were small, the results may help advance research and intervention development with respect to e-cigarette initiation, maintenance and cessation. PMID:26406973

Gender differences in use and expectancies of e-cigarettes: Online survey results.

PubMed

Piñeiro, Bárbara; Correa, John B; Simmons, Vani N; Harrell, Paul T; Menzie, Nicole S; Unrod, Marina; Meltzer, Lauren R; Brandon, Thomas H

2016-01-01

Given the rapid increase in e-cigarette use, it is important to understand factors that may contribute to their initiation and maintenance. Because gender differences in tobacco use, product preferences, and expectancies are well established, similar gender differences may exist with e-cigarettes. The aim of this study was to identify gender differences among e-cigarette users in patterns of use, reasons for initiation and maintenance, and outcome expectancies regarding e-cigarettes. Participants (N=1815) completed an online survey from August through November, 2013. We assessed sociodemographics, smoking and e-cigarette history and use, and expectancies about e-cigarettes. We found gender differences in type of e-cigarette used, flavors used, nicotine dosage, source of information about e-cigarettes, place of purchase, and use of e-cigarettes where smoking is prohibited. In addition, males were more likely to report initiating e-cigarette use to quit smoking due to health concerns, whereas females were more likely to report initiation based on recommendations from family and friends. Males reported higher attributions for maintenance of e-cigarette use related to positive reinforcement (enjoyment), whereas females reported higher negative reinforcement attributions (stress reduction or mood management). Males reported more positive expectancies about e-cigarettes, including taste, social facilitation, and energy, whereas women rated e-cigarettes higher for weight control. Males also reported greater addiction-related e-cigarette expectancy than females. Many of the gender differences with e-cigarettes parallel those previously found with traditional cigarette smoking. Although effect sizes associated with these differences were small, the results may help advance research and intervention development with respect to e-cigarette initiation, maintenance and cessation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cognitive risk factors of electronic and combustible cigarette use in adolescents.

PubMed

Lechner, William V; Murphy, Cara M; Colby, Suzanne M; Janssen, Tim; Rogers, Michelle L; Jackson, Kristina M

2018-07-01

Cognitive susceptibility to cigarette smoking has been demonstrated to predict future cigarette initiation in adolescents. Examining this construct prior to tobacco product initiation may provide useful information on the differential risk of individuals initiating cigarette vs. e-cigarette products. Additionally, examining how susceptibility and tobacco product use relate to perceived harm cognitions will increase understanding of risk predisposition among adolescents. Data were taken from a longitudinal study of middle school students (n = 1023; age = 12.1, 52.2% female, 72.1% white) in the Northeastern U.S. Likelihood of e-cigarette and cigarette ever-use in high school was examined as a function of a validated index of cigarette smoking susceptibility among tobacco naïve students in middle school. Prospective associations between cognitive susceptibility to smoking and subsequent perceived harm of e-cigarettes (assessed in high school), and cross-sectional associations between concurrent tobacco product ever-use status and perceived harm of e-cigarettes were examined. Adolescents classified as susceptible to cigarette smoking in middle school were more likely to initiate use of cigarettes (OR = 2.53) and e-cigarettes (OR = 1.95) as compared to adolescents classified as non-susceptible; cigarette smoking susceptibility did not differentially predict use of one product over the other. Adolescents endorsing e-cigarette use, reported significantly less perceived harm associated with e-cigarettes vs. cigarettes, while those who endorsed cigarette only or dual use did not. Our data indicate that cognitive susceptibility to cigarette smoking may index a broad risk factor for using either cigarettes or e-cigarettes in the future, and is prospectively associated with perceived harm of e-cigarette use. Overall, those who used any tobacco product perceived e-cigarettes as less harmful when compared to abstainers. Individual facets of perceived harm (addiction potential and harm vs. cigarettes) differ between cigarette only users and e-cigarette users and may help to explain the choice to use one product vs. the other. This is the first study to examine prospective associations between cognitive susceptibility to cigarette smoking, predating tobacco use, and subsequent likelihood of cigarette vs. e-cigarette initiation. This study demonstrates that initiation of either product is elevated among youth who are susceptible to smoking; thus susceptibility to smoking may serve as a useful marker of vulnerability to tobacco product use. Furthermore, this study provides novel information on the relationship between tobacco product onset and specific harm perceptions associated with e-cigarettes versus cigarettes among adolescents. Copyright © 2018 Elsevier Ltd. All rights reserved.

High-Frequency Neuromuscular Electrical Stimulation Increases Anabolic Signaling.

PubMed

Mettler, Joni A; Magee, Dillon M; Doucet, Barbara M

2018-03-16

Neuromuscular electrical stimulation (NMES) is commonly used in rehabilitation settings to increase muscle mass and strength. However, the effects of NMES on muscle growth are not clear and no human studies have compared anabolic signaling between low-frequency (LF-) and high-frequency (HF-) NMES. The purpose of this study was to determine the skeletal muscle anabolic signaling response to an acute bout of LF- and HF-NMES. Eleven young healthy volunteers (6 men; 5 women) received an acute bout of LF- (20 Hz) and HF- (60 Hz) NMES. Muscle biopsies were obtained from the vastus lateralis muscle prior to the first NMES treatment and 30-mins following each NMES treatment. Phosphorylation of the following key anabolic signaling proteins was measured by Western blot and proteins are expressed as a ratio of phosphorylated to total: mammalian target of rapamycin (mTOR), p70-S6 kinase 1 (S6K1), and eukaryotic initiation factor 4E binding protein 1 (4E-BP1). Compared to Pre-NMES, phosphorylation of mTOR was upregulated 40.2% for LF-NMES (P = 0.018) and 68.4% for HF-NMES (P < 0.0001) and HF-NMES was 29.3% greater than LF-NMES (P = 0.026). Phosphorylation of S6K1 after HF-NMES was 96.6% higher than Pre-NMES (P = 0.001), was not different between Pre-NMES and LF-NMES (although was 50.4% higher after LF-) or LF- and HF-NMES (P > 0.05). There were no differences between treatment conditions for 4E-BP1 phosphorylation (P > 0.05). An acute bout of LF- and HF-NMES upregulated anabolic signaling with HF-NMES producing a greater anabolic response compared to LF-NMES, suggesting that HF-stimulation may provide a stronger stimulus for processes that initiate muscle hypertrophy. Additionally, the stimulation frequency parameter should be considered by clinicians in the design of optimal NMES treatment protocols.

Factors influencing smokeless tobacco use in rural Ohio Appalachia.

PubMed

Nemeth, Julianna M; Liu, Sherry T; Klein, Elizabeth G; Ferketich, Amy K; Kwan, Mei-Po; Wewers, Mary Ellen

2012-12-01

The burden of smokeless tobacco (ST) use disproportionally impacts males in rural Ohio Appalachia. The purpose of this study was to describe the cultural factors contributing to this disparity and to articulate the way in which culture, through interpersonal factors (i.e. social norms and social networks) and community factors (i.e. marketing and availability), impacts ST initiation and use of ST among boys and men in Ohio Appalachia. Fifteen focus groups and 23 individual qualitative interviews were conducted with adult (n = 63) and adolescent (n = 53) residents in Ohio Appalachian counties to ascertain factors associated with ST use and the impact of ST marketing. Transcriptions were independently coded according to questions and themes. ST use appears to be a rite of passage in the development of masculine identity in Ohio Appalachian culture. Interpersonal factors had the greatest influence on initiation and continued use of ST. Ohio Appalachian boys either emulated current ST users or were actively encouraged to use ST through male family and peer networks. Users perceived their acceptance into the male social network as predicated on ST use. Community factors, including ST advertisement and access to ST, reinforced and normalized underlying cultural values. In addition to policy aimed at reducing tobacco marketing and access, interventions designed to reduce ST use in Ohio Appalachia should incorporate efforts to (1) shift the perception of cultural norms regarding ST use and (2) address male social networks as vehicles in ST initiation.

Human Management of a Wild Plant Modulates the Evolutionary Dynamics of a Gene Determining Recessive Resistance to Virus Infection

PubMed Central

Poulicard, Nils; Pacios, Luis Fernández; Gallois, Jean-Luc; Piñero, Daniel; García-Arenal, Fernando

2016-01-01

This work analyses the genetic variation and evolutionary patterns of recessive resistance loci involved in matching-allele (MA) host-pathogen interactions, focusing on the pvr2 resistance gene to potyviruses of the wild pepper Capsicum annuum glabriusculum (chiltepin). Chiltepin grows in a variety of wild habitats in Mexico, and its cultivation in home gardens started about 25 years ago. Potyvirus infection of Capsicum plants requires the physical interaction of the viral VPg with the pvr2 product, the translation initiation factor eIF4E1. Mutations impairing this interaction result in resistance, according to the MA model. The diversity of pvr2/eIF4E1 in wild and cultivated chiltepin populations from six biogeographical provinces in Mexico was analysed in 109 full-length coding sequences from 97 plants. Eleven alleles were found, and their interaction with potyvirus VPg in yeast-two-hybrid assays, plus infection assays of plants, identified six resistance alleles. Mapping resistance mutations on a pvr2/eIF4E1 model structure showed that most were around the cap-binding pocket and strongly altered its surface electrostatic potential, suggesting resistance-associated costs due to functional constraints. The pvr2/eIF4E1 phylogeny established that susceptibility was ancestral and resistance was derived. The spatial structure of pvr2/eIF4E1 diversity differed from that of neutral markers, but no evidence of selection for resistance was found in wild populations. In contrast, the resistance alleles were much more frequent, and positive selection stronger, in cultivated chiltepin populations, where diversification of pvr2/eIF4E1 was higher. This analysis of the genetic variation of a recessive resistance gene involved in MA host-pathogen interactions in populations of a wild plant show that evolutionary patterns differ according to the plant habitat, wild or cultivated. It also demonstrates that human management of the plant population has profound effects on the diversity and the evolution of the resistance gene, resulting in the selection of resistance alleles. PMID:27490800

Human Management of a Wild Plant Modulates the Evolutionary Dynamics of a Gene Determining Recessive Resistance to Virus Infection.

PubMed

Poulicard, Nils; Pacios, Luis Fernández; Gallois, Jean-Luc; Piñero, Daniel; García-Arenal, Fernando

2016-08-01

This work analyses the genetic variation and evolutionary patterns of recessive resistance loci involved in matching-allele (MA) host-pathogen interactions, focusing on the pvr2 resistance gene to potyviruses of the wild pepper Capsicum annuum glabriusculum (chiltepin). Chiltepin grows in a variety of wild habitats in Mexico, and its cultivation in home gardens started about 25 years ago. Potyvirus infection of Capsicum plants requires the physical interaction of the viral VPg with the pvr2 product, the translation initiation factor eIF4E1. Mutations impairing this interaction result in resistance, according to the MA model. The diversity of pvr2/eIF4E1 in wild and cultivated chiltepin populations from six biogeographical provinces in Mexico was analysed in 109 full-length coding sequences from 97 plants. Eleven alleles were found, and their interaction with potyvirus VPg in yeast-two-hybrid assays, plus infection assays of plants, identified six resistance alleles. Mapping resistance mutations on a pvr2/eIF4E1 model structure showed that most were around the cap-binding pocket and strongly altered its surface electrostatic potential, suggesting resistance-associated costs due to functional constraints. The pvr2/eIF4E1 phylogeny established that susceptibility was ancestral and resistance was derived. The spatial structure of pvr2/eIF4E1 diversity differed from that of neutral markers, but no evidence of selection for resistance was found in wild populations. In contrast, the resistance alleles were much more frequent, and positive selection stronger, in cultivated chiltepin populations, where diversification of pvr2/eIF4E1 was higher. This analysis of the genetic variation of a recessive resistance gene involved in MA host-pathogen interactions in populations of a wild plant show that evolutionary patterns differ according to the plant habitat, wild or cultivated. It also demonstrates that human management of the plant population has profound effects on the diversity and the evolution of the resistance gene, resulting in the selection of resistance alleles.

Construction and validation of a measure of integrative well-being in seven languages: the Pemberton Happiness Index.

PubMed

Hervás, Gonzalo; Vázquez, Carmelo

2013-04-22

We introduce the Pemberton Happiness Index (PHI), a new integrative measure of well-being in seven languages, detailing the validation process and presenting psychometric data. The scale includes eleven items related to different domains of remembered well-being (general, hedonic, eudaimonic, and social well-being) and ten items related to experienced well-being (i.e., positive and negative emotional events that possibly happened the day before); the sum of these items produces a combined well-being index. A distinctive characteristic of this study is that to construct the scale, an initial pool of items, covering the remembered and experienced well-being domains, were subjected to a complete selection and validation process. These items were based on widely used scales (e.g., PANAS, Satisfaction With Life Scale, Subjective Happiness Scale, and Psychological Well-Being Scales). Both the initial items and reference scales were translated into seven languages and completed via Internet by participants (N = 4,052) aged 16 to 60 years from nine countries (Germany, India, Japan, Mexico, Russia, Spain, Sweden, Turkey, and USA). Results from this initial validation study provided very good support for the psychometric properties of the PHI (i.e., internal consistency, a single-factor structure, and convergent and incremental validity). Given the PHI's good psychometric properties, this simple and integrative index could be used as an instrument to monitor changes in well-being. We discuss the utility of this integrative index to explore well-being in individuals and communities.

[Role of hepatitis A and E viruses in the development of autoimmune diseases].

PubMed

Iakimchuk, K S; Malinnikova, E Iu; Poleshchuk, V F; Mikhaĭlov, M I

2011-01-01

The mechanisms of development of autoimmune diseases may be associated with a complex of genetic, immune, hormonal, and infectious factors. Autoimmune diseases include a wide range of systemic and organ-specific diseases, including autoimmune hepatitis (AIH). It is currently assumed that the pathogenesis of AIH is due to compromised immune regulation in the presence of an exogenous triggering factor. Exogenous factors, such as viruses, may be triggers of AIH. There may be different ways of initiating an autoimmune response by viruses, which includes nonspecific T-lymphocyte activation and molecular mimicry. There is much evidence supporting the initiating role of hepatitis viruses in the development of AIH and other autoimmune diseases. The development of AIH symptoms during hepatitis A and E virus infections has been described elsewhere. The creation of animal models of viral hepatitis is required to confirm the hypothesis that the viruses trigger the development of AIH and other autoimmune manifestations.

Nutritional and regulatory roles of leucine in muscle growth and fat reduction.

PubMed

Duan, Yehui; Li, Fengna; Liu, Hongnan; Li, Yinghui; Liu, Yingying; Kong, Xiangfeng; Zhang, Yuzhe; Deng, Dun; Tang, Yulong; Feng, Zemeng; Wu, Guoyao; Yin, Yulong

2015-01-01

The metabolic roles for L-leucine, an essential branched-chain amino acid (BCAA), go far beyond serving exclusively as a building block for de novo protein synthesis. Growing evidence shows that leucine regulates protein and lipid metabolism in animals. Specifically, leucine activates the mammalian target of rapamycin (mTOR) signaling pathway, including the 70 kDa ribosomal protein S6 kinase 1 (S6K1) and eukaryotic initiation factor (eIF) 4E-binding protein 1 (4EBP1) to stimulate protein synthesis in skeletal muscle and adipose tissue and to promote mitochondrial biogenesis, resulting in enhanced cellular respiration and energy partitioning. Activation of cellular energy metabolism favors fatty acid oxidation to CO2 and water in adipocytes, lean tissue gain in young animals, and alleviation of muscle protein loss in aging adults, lactating mammals, and food-deprived subjects. As a functional amino acid, leucine holds great promise to enhance the growth, efficiency of food utilization, and health of animals and humans. 

Fractionation and reconstitution of factors required for accurate transcription of mammalian ribosomal RNA genes: identification of a species-dependent initiation factor.

PubMed Central

Mishima, Y; Financsek, I; Kominami, R; Muramatsu, M

1982-01-01

Mouse and human cell extracts (S100) can support an accurate and efficient transcription initiation on homologous ribosomal RNA gene (rDNA) templates. The cell extracts were fractionated with the aid of a phosphocellulose column into four fractions (termed A, B, C and D), including one containing a major part of the RNA polymerase I activity. Various reconstitution experiments indicate that fraction D is an absolute requirement for the correct and efficient transcription initiation by RNA polymerase I on both mouse and human genes. Fraction B effectively suppresses random initiation on these templates. Fraction A appears to further enhance the transcription which takes place with fractions C and D. Although fractions A, B and C are interchangeable between mouse and human extracts, fraction D is not; i.e. initiation of transcription required the presence of a homologous fraction D for both templates. The factor(s) in fraction D, however, is not literally species-specific, since mouse D fraction is capable of supporting accurate transcription initiation on a rat rDNA template in the presence of all the other fractions from human cell extract under the conditions where human D fraction is unable to support it. We conclude from these experiments that a species-dependent factor in fraction D plays an important role in the initiation of rDNA transcription in each animal species. Images PMID:7177852

SOX4 is essential for prostate tumorigenesis initiated by PTEN ablation | Office of Cancer Genomics

Cancer.gov

Understanding remains incomplete of the mechanisms underlying initiation and progression of prostate cancer, the most commonly diagnosed cancer in American men. The transcription factor SOX4 is overexpressed in many human cancers, including prostate cancer, suggesting it may participate in prostate tumorigenesis. In this study, we investigated this possibility by genetically deleting Sox4 in a mouse model of prostate cancer initiated by loss of the tumor suppressor Pten.

Association of High Myopia with Crystallin Beta A4 (CRYBA4) Gene Polymorphisms in the Linkage-Identified MYP6 Locus

PubMed Central

Ho, Daniel W. H.; Yap, Maurice K. H.; Ng, Po Wah; Fung, Wai Yan; Yip, Shea Ping

2012-01-01

Background Myopia is the most common ocular disorder worldwide and imposes tremendous burden on the society. It is a complex disease. The MYP6 locus at 22 q12 is of particular interest because many studies have detected linkage signals at this interval. The MYP6 locus is likely to contain susceptibility gene(s) for myopia, but none has yet been identified. Methodology/Principal Findings Two independent subject groups of southern Chinese in Hong Kong participated in the study an initial study using a discovery sample set of 342 cases and 342 controls, and a follow-up study using a replication sample set of 316 cases and 313 controls. Cases with high myopia were defined by spherical equivalent ≤ -8 dioptres and emmetropic controls by spherical equivalent within ±1.00 dioptre for both eyes. Manual candidate gene selection from the MYP6 locus was supported by objective in silico prioritization. DNA samples of discovery sample set were genotyped for 178 tagging single nucleotide polymorphisms (SNPs) from 26 genes. For replication, 25 SNPs (tagging or located at predicted transcription factor or microRNA binding sites) from 4 genes were subsequently examined using the replication sample set. Fisher P value was calculated for all SNPs and overall association results were summarized by meta-analysis. Based on initial and replication studies, rs2009066 located in the crystallin beta A4 (CRYBA4) gene was identified to be the most significantly associated with high myopia (initial study: P = 0.02; replication study: P = 1.88e-4; meta-analysis: P = 1.54e-5) among all the SNPs tested. The association result survived correction for multiple comparisons. Under the allelic genetic model for the combined sample set, the odds ratio of the minor allele G was 1.41 (95% confidence intervals, 1.21-1.64). Conclusions/Significance A novel susceptibility gene (CRYBA4) was discovered for high myopia. Our study also signified the potential importance of appropriate gene prioritization in candidate selection. PMID:22792142

Inclusive Higgs boson production at the LHC in the kT -factorization approach

NASA Astrophysics Data System (ADS)

Abdulov, N. A.; Lipatov, A. V.; Malyshev, M. A.

2018-03-01

We investigate the inclusive Higgs boson production in proton-proton collisions at the CERN LHC conditions using the kT-factorization approach. Our analysis is based on the dominant off-shell gluon-gluon fusion subprocess (where the transverse momenta of initial gluons are taken into account) and covers H →γ γ , H →Z Z*→4 l (where l =e , μ ) and H →W+W-→e±μ∓ν ν ¯ decay channels. The transverse momentum dependent (or unintegrated) gluon densities in a proton were derived from Ciafaloni-Catani-Fiorani-Marchesini equation, which resums large logarithmic terms proportional to ln s ˜ln 1 /x , important at high energies. As an alternative choice, we apply the Kimber-Martin-Ryskin prescription, where the transverse momentum dependent gluon density is constructed from the known conventional parton distributions. We estimate the theoretical uncertainties of our calculations and compare our results with next-to-next-to-leading-order plus next-to-next-to-leading-logarithmic ones obtained using collinear QCD factorization. Our predictions agree well with the latest experimental data taken by the CMS and ATLAS Collaborations at √{s }=8 and 13 TeV.

AUU-to-AUG mutation in the initiator codon of the translation initiation factor IF3 abolishes translational autocontrol of its own gene (infC) in vivo.

PubMed Central

Butler, J S; Springer, M; Grunberg-Manago, M

1987-01-01

We previously showed that Escherichia coli translation initiation factor IF3 regulates the expression of its own gene infC at the translational level in vivo. Here we create two alterations in the infC gene and test their effects on translational autocontrol of infC expression in vivo by measuring beta-galactosidase activity expressed from infC-lacZ gene fusions under conditions of up to 4-fold derepression or 3-fold repression of infC expression. Replacement of the infC promoter with the trp promoter deletes 120 nucleotides of the infC mRNA 5' to the translation initiation site without affecting autogenous translational control. Mutation of the unusual AUU initiator codon of infC to the more common AUG initiator codon abolishes translation initiation factor IF3-dependent repression and derepression of infC expression in vivo. These results establish the AUU initiator codon of infC as an essential cis-acting element in autogenous translational control of translation initiation factor IF3 expression in vivo. PMID:2954162

AUU-to-AUG mutation in the initiator codon of the translation initiation factor IF3 abolishes translational autocontrol of its own gene (infC) in vivo.

PubMed

Butler, J S; Springer, M; Grunberg-Manago, M

1987-06-01

We previously showed that Escherichia coli translation initiation factor IF3 regulates the expression of its own gene infC at the translational level in vivo. Here we create two alterations in the infC gene and test their effects on translational autocontrol of infC expression in vivo by measuring beta-galactosidase activity expressed from infC-lacZ gene fusions under conditions of up to 4-fold derepression or 3-fold repression of infC expression. Replacement of the infC promoter with the trp promoter deletes 120 nucleotides of the infC mRNA 5' to the translation initiation site without affecting autogenous translational control. Mutation of the unusual AUU initiator codon of infC to the more common AUG initiator codon abolishes translation initiation factor IF3-dependent repression and derepression of infC expression in vivo. These results establish the AUU initiator codon of infC as an essential cis-acting element in autogenous translational control of translation initiation factor IF3 expression in vivo.

La-related Protein 1 (LARP1) Represses Terminal Oligopyrimidine (TOP) mRNA Translation Downstream of mTOR Complex 1 (mTORC1).

PubMed

Fonseca, Bruno D; Zakaria, Chadi; Jia, Jian-Jun; Graber, Tyson E; Svitkin, Yuri; Tahmasebi, Soroush; Healy, Danielle; Hoang, Huy-Dung; Jensen, Jacob M; Diao, Ilo T; Lussier, Alexandre; Dajadian, Christopher; Padmanabhan, Niranjan; Wang, Walter; Matta-Camacho, Edna; Hearnden, Jaclyn; Smith, Ewan M; Tsukumo, Yoshinori; Yanagiya, Akiko; Morita, Masahiro; Petroulakis, Emmanuel; González, Jose L; Hernández, Greco; Alain, Tommy; Damgaard, Christian K

2015-06-26

The mammalian target of rapamycin complex 1 (mTORC1) is a critical regulator of protein synthesis. The best studied targets of mTORC1 in translation are the eukaryotic initiation factor-binding protein 1 (4E-BP1) and ribosomal protein S6 kinase 1 (S6K1). In this study, we identify the La-related protein 1 (LARP1) as a key novel target of mTORC1 with a fundamental role in terminal oligopyrimidine (TOP) mRNA translation. Recent genome-wide studies indicate that TOP and TOP-like mRNAs compose a large portion of the mTORC1 translatome, but the mechanism by which mTORC1 controls TOP mRNA translation is incompletely understood. Here, we report that LARP1 functions as a key repressor of TOP mRNA translation downstream of mTORC1. Our data show the following: (i) LARP1 associates with mTORC1 via RAPTOR; (ii) LARP1 interacts with TOP mRNAs in an mTORC1-dependent manner; (iii) LARP1 binds the 5'TOP motif to repress TOP mRNA translation; and (iv) LARP1 competes with the eukaryotic initiation factor (eIF) 4G for TOP mRNA binding. Importantly, from a drug resistance standpoint, our data also show that reducing LARP1 protein levels by RNA interference attenuates the inhibitory effect of rapamycin, Torin1, and amino acid deprivation on TOP mRNA translation. Collectively, our findings demonstrate that LARP1 functions as an important repressor of TOP mRNA translation downstream of mTORC1. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

La-related Protein 1 (LARP1) Represses Terminal Oligopyrimidine (TOP) mRNA Translation Downstream of mTOR Complex 1 (mTORC1)*

PubMed Central

Fonseca, Bruno D.; Zakaria, Chadi; Jia, Jian-Jun; Graber, Tyson E.; Svitkin, Yuri; Tahmasebi, Soroush; Healy, Danielle; Hoang, Huy-Dung; Jensen, Jacob M.; Diao, Ilo T.; Lussier, Alexandre; Dajadian, Christopher; Padmanabhan, Niranjan; Wang, Walter; Matta-Camacho, Edna; Hearnden, Jaclyn; Smith, Ewan M.; Tsukumo, Yoshinori; Yanagiya, Akiko; Morita, Masahiro; Petroulakis, Emmanuel; González, Jose L.; Hernández, Greco; Alain, Tommy; Damgaard, Christian K.

2015-01-01

The mammalian target of rapamycin complex 1 (mTORC1) is a critical regulator of protein synthesis. The best studied targets of mTORC1 in translation are the eukaryotic initiation factor-binding protein 1 (4E-BP1) and ribosomal protein S6 kinase 1 (S6K1). In this study, we identify the La-related protein 1 (LARP1) as a key novel target of mTORC1 with a fundamental role in terminal oligopyrimidine (TOP) mRNA translation. Recent genome-wide studies indicate that TOP and TOP-like mRNAs compose a large portion of the mTORC1 translatome, but the mechanism by which mTORC1 controls TOP mRNA translation is incompletely understood. Here, we report that LARP1 functions as a key repressor of TOP mRNA translation downstream of mTORC1. Our data show the following: (i) LARP1 associates with mTORC1 via RAPTOR; (ii) LARP1 interacts with TOP mRNAs in an mTORC1-dependent manner; (iii) LARP1 binds the 5′TOP motif to repress TOP mRNA translation; and (iv) LARP1 competes with the eukaryotic initiation factor (eIF) 4G for TOP mRNA binding. Importantly, from a drug resistance standpoint, our data also show that reducing LARP1 protein levels by RNA interference attenuates the inhibitory effect of rapamycin, Torin1, and amino acid deprivation on TOP mRNA translation. Collectively, our findings demonstrate that LARP1 functions as an important repressor of TOP mRNA translation downstream of mTORC1. PMID:25940091

The HPV16 E7 oncoprotein increases the expression of Oct3/4 and stemness-related genes and augments cell self-renewal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Organista-Nava, Jorge; Gómez-Gómez, Yazmín

Oct3/4 is a transcription factor involved in maintenance of the pluripotency and self-renewal of stem cells. The E7 oncoprotein and 17β-estradiol (E{sub 2}) are key factors in cervical carcinogenesis. In the present study, we aimed to investigate the effect of the HPV16 E7 oncoprotein and E{sub 2} on the expression pattern of Oct3/4, Sox2, Nanog and Fgf4. We also determined whether the E7 oncoprotein is associated with cell self-renewal. The results showed that Oct3/4, Sox2, Nanog and Fgf4 were upregulated by the E7 oncoprotein in vivo and in vitro and implicate E{sub 2} in the upregulation of these factors inmore » vivo. We also demonstrated that E7 is involved in cell self-renewal, suggesting that the HPV16 E7 oncoprotein upregulates Oct3/4, Sox2, Nanog and Fgf4 expression to maintain the self-renewal capacity of cancer stem cells. -- Graphical abstract: The HPV16 E7 oncoprotein and 17β-estradiol are involved in the upregulation of Oct3/4, Sox2, Nanog and Fgf4 expression to maintain the self-renewal ability of cancer stem cells in cervical cancer. - Highlights: •The HPV16 E7 oncoprotein enhances cellular proliferation and dedifferentiation. •The E7 oncoprotein induces stemness-related genes expression in vivo and in vitro. •The 17β-estradiol induces stemness-related genes expression in vivo. •The HPV16 E7 oncoprotein is involved in the cell self-renewal of cancer cells.« less

Long-term mortality in HIV-positive individuals virally suppressed for >3 years with incomplete CD4 recovery.

PubMed

Engsig, Frederik N; Zangerle, Robert; Katsarou, Olga; Dabis, Francois; Reiss, Peter; Gill, John; Porter, Kholoud; Sabin, Caroline; Riordan, Andrew; Fätkenheuer, Gerd; Gutiérrez, Félix; Raffi, Francois; Kirk, Ole; Mary-Krause, Murielle; Stephan, Christoph; de Olalla, Patricia Garcia; Guest, Jodie; Samji, Hasina; Castagna, Antonella; d'Arminio Monforte, Antonella; Skaletz-Rorowski, Adriane; Ramos, Jose; Lapadula, Giuseppe; Mussini, Cristina; Force, Lluís; Meyer, Laurence; Lampe, Fiona; Boufassa, Faroudy; Bucher, Heiner C; De Wit, Stéphane; Burkholder, Greer A; Teira, Ramon; Justice, Amy C; Sterling, Tim R; M Crane, Heidi; Gerstoft, Jan; Grarup, Jesper; May, Margaret; Chêne, Geneviève; Ingle, Suzanne M; Sterne, Jonathan; Obel, Niels

2014-05-01

Some human immunodeficiency virus (HIV)-infected individuals initiating combination antiretroviral therapy (cART) with low CD4 counts achieve viral suppression but not CD4 cell recovery. We aimed to identify (1) risk factors for failure to achieve CD4 count >200 cells/µL after 3 years of sustained viral suppression and (2) the association of the achieved CD4 count with subsequent mortality. We included treated HIV-infected adults from 2 large international HIV cohorts, who had viral suppression (≤500 HIV type 1 RNA copies/mL) for >3 years with CD4 count ≤200 cells/µL at start of the suppressed period. Logistic regression was used to identify risk factors for incomplete CD4 recovery (≤200 cells/µL) and Cox regression to identify associations with mortality. Of 5550 eligible individuals, 835 (15%) did not reach a CD4 count >200 cells/µL after 3 years of suppression. Increasing age, lower initial CD4 count, male heterosexual and injection drug use transmission, cART initiation after 1998, and longer time from initiation of cART to start of the virally suppressed period were risk factors for not achieving a CD4 count >200 cells/µL. Individuals with CD4 ≤200 cells/µL after 3 years of viral suppression had substantially increased mortality (adjusted hazard ratio, 2.60; 95% confidence interval, 1.86-3.61) compared with those who achieved CD4 count >200 cells/µL. The increased mortality was seen across different patient groups and for all causes of death. Virally suppressed HIV-positive individuals on cART who do not achieve a CD4 count >200 cells/µL have substantially increased long-term mortality.

E-cigarettes: Impact of E-Liquid Components and Device Characteristics on Nicotine Exposure.

PubMed

DeVito, Elise E; Krishnan-Sarin, Suchitra

2018-01-01

Electronic cigarette (e-cigarette) use has increased substantially in recent years. While e-cigarettes have been proposed as a potentially effective smoking cessation tool, dualuse in smokers is common and e-cigarettes are widely used by non-smokers, including youth and young-adult non-smokers. Nicotine, the primary addictive component in cigarettes, is present at varying levels in many e-liquids. E-cigarettes may lead to initiation of nicotine use in adult and youth non-smokers, re-initiation of nicotine dependence in ex-smokers or increased severity of nicotine dependence in dual-users of cigarettes and e-cigarettes. As such, there are important clinical and policy implications to understanding factors impacting nicotine exposure from e-cigarettes. However, the broad and rapidly changing range of e-liquid constituents and e-cigarette hardware which could impact nicotine exposure presents a challenge. Recent changes in regulatory oversight of e-cigarettes underscore the importance of synthesizing current knowledge on common factors which may impact nicotine exposure. This review focuses on factors which may impact nicotine exposure by changing e-cigarette use behavior, puff topography, altering the nicotine yield (amount of nicotine exiting the e-cigarette mouth piece including nicotine exhaled as vapor) or more directly by altering nicotine absorption and bioavailability. Topics reviewed include e-liquid components or characteristics including flavor additives (e.g., menthol), base e-liquid ingredients (propylene glycol, vegetable glycerin), components commonly used to dissolve flavorants (e.g., ethanol), and resulting properties of the e-liquid (e.g., pH), e-cigarette device characteristics (e.g., wattage, temperature, model) and user behavior (e.g., puff topography) which may impact nicotine exposure. E-liquid characteristics and components, e-cigarette hardware and settings, and user behavior can all contribute substantially to nicotine exposure from e-cigarettes. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Incidence and risk factors of severe adverse events with nevirapine-based antiretroviral therapy in HIV-infected women. MTCT-Plus program, Abidjan, Côte d'Ivoire

PubMed Central

2010-01-01

Background In resource-limited settings where nevirapine-containing regimen is the preferred regimen in women, data on severe adverse events (SAEs) according to CD4 cell count are limited. We estimated the incidence of SAEs according to CD4 cell count and identify their risk factors in nevirapine-treated women. Methods All HIV-infected women who initiated nevirapine-containing regimen in the MTCT-Plus operational program in Abidjan, Côte d'Ivoire, were eligible for this study. Laboratory and clinical (rash) SAEs were classified as grade 3 and 4. Cox models were used to identify factors associated with the occurrence of SAEs. Results From August 2003 to October 2006, 290 women initiated a nevirapine-containing regimen at a median CD4 cell count of 186 cells/mm3 (IQR 124-266). During a median follow-up on treatment of 25 months, the incidence of all SAEs was 19.5/100 patient-years. The 24-month probability of occurrence of hepatotoxicity or rash was not different between women with a CD4 cell count >250 cells/mm3 and women with a CD4 cell count ≤250 cells/mm3 (8.3% vs. 9.9%, Log-rank test: p = 0.75). In a multivariate proportional hazard model, neither CD4 cell count >250 cells/mm3 at treatment initiation nor initiation NVP-based regimen initiated during pregnancy were associated with the occurrence of SAEs. Conclusion CD4 cell count >250 cells/mm3 was not associated with a higher risk of severe hepatotoxicity and/or rash, as well as initiation of ART during pregnancy. Pharmacovogilance data as well as meta-analysis on women receiving NVP in these settings are needed for better information about NVP toxicity. PMID:20576111

Insights into the species-specific TLR4 signaling mechanism in response to Rhodobacter sphaeroides lipid A detection

NASA Astrophysics Data System (ADS)

Anwar, Muhammad Ayaz; Panneerselvam, Suresh; Shah, Masaud; Choi, Sangdun

2015-01-01

TLR4 in complex with MD2 senses the presence of lipid A (LA) and initiates a signaling cascade that curb the infection. This complex is evolutionarily conserved and can initiate the immune system in response to a variety of LAs. In this study, molecular dynamics simulation (25 ns) was performed to elucidate the differential behavior of TLR4/MD2 complex in response to Rhodobacter sphaeroides lipid A (RsLA). Penta-acyl chain-containing RsLA is at the verge of agonist (6 acyl-chains) and antagonist (4 acyl-chains) structure, and activates the TLR4 pathway in horses and hamsters, while inhibiting in humans and murine. In the time-evolved coordinates, the promising factors that dictated the differential response included the local and global mobility pattern of complexes, solvent-accessible surface area of ligand, and surface charge distributions of TLR4 and MD2. We showed that the GlcN1-GlcN2 backbone acquires agonist (3FXI)-like configurations in horses and hamsters, while acquiring antagonist (2E59)-like configurations in humans and murine systems. Moreover, analysis of F126 behavior in the MD2 F126 loop (amino acids 123-129) and loop EF (81-89) suggested that certain sequence variations also contribute to species-specific response. This study underlines the TLR4 signaling mechanism and provides new therapeutic opportunities.

Complement, Kinins, and Hereditary Angioedema: Mechanisms of Plasma Instability when C1 Inhibitor is Absent.

PubMed

Kaplan, Allen P; Joseph, Kusumam

2016-10-01

Plasma of patients with types I and II hereditary angioedema is unstable if incubated in a plastic (i.e., inert) vessel at 37 °C manifested by progressively increasing formation of bradykinin. There is also a persistent low level of C4 in 95 % of patients even when they are symptomatic. These phenomena are due to the properties of the C1r subcomponent of C1, factor XII, and the bimolecular complex of prekallikrein with high molecular weight kininogen (HK). Purified C1r auto-activates in physiologic buffers, activates C1s, which in turn depletes C4. This occurs when C1 inhibitor is deficient. The complex of prekallikrein-HK acquires an inducible active site not present in prekallikrein which in Tris-type buffers cleaves HK stoichiometrically to release bradykinin, or in phosphate buffer auto-activates to generate kallikrein and bradykinin. Thus immunologic depletion of C1 inhibitor from factor XII-deficient plasma (phosphate is the natural buffer) auto-activates on incubation to release bradykinin. Normal C1 inhibitor prevents this from occurring. During attacks of angioedema, if factor XII auto-activates on surfaces, the initial factor XIIa formed converts prekallikrein to kallikrein, and kallikrein cleaves HK to release bradykinin. Kallikrein also rapidly activates most remaining factor XII to factor XIIa. Additional cleavages convert factor XIIa to factor XIIf and factor XIIf activates C1r enzymatically so that C4 levels approach zero, and C2 is depleted. There is also a possibility that kallikrein is generated first as a result of activation of the prekallikrein-HK complex by heat shock protein 90 released from endothelial cells, followed by kallikrein activation of factor XII.

Cohort Profile: HAART Observational Medical Evaluation and Research (HOMER) Cohort

PubMed Central

Patterson, Sophie; Cescon, Angela; Samji, Hasina; Cui, Zishan; Yip, Benita; Lepik, Katherine J; Moore, David; Lima, Viviane D; Nosyk, Bohdan; Harrigan, P Richard; Montaner, Julio SG; Shannon, Kate; Wood, Evan; Hogg, Robert S

2015-01-01

Since 1986, antiretroviral therapy (ART) has been available free of charge to individuals living with HIV in British Columbia (BC), Canada, through the BC Centre of Excellence in HIV/AIDS (BC-CfE) Drug Treatment Program (DTP). The Highly Active Antiretroviral Therapy (HAART) Observational Medical Evaluation and Research (HOMER) cohort was established in 1996 to maintain a prospective record of clinical measurements and medication profiles of a subset of DTP participants initiating HAART in BC. This unique cohort provides a comprehensive data source to investigate mortality, prognostic factors and treatment response among people living with HIV in BC from the inception of HAART. Currently over 5000 individuals are enrolled in the HOMER cohort. Data captured include socio-demographic characteristics (e.g. sex, age, ethnicity, health authority), clinical variables (e.g. CD4 cell count, plasma HIV viral load, AIDS-defining illness, hepatitis C co-infection, mortality) and treatment variables (e.g. HAART regimens, date of treatment initiation, treatment interruptions, adherence data, resistance testing). Research findings from the HOMER cohort have featured in numerous high-impact peer-reviewed journals. The HOMER cohort collaborates with other HIV cohorts on both national and international scales to answer complex HIV-specific research questions, and welcomes input from external investigators regarding potential research proposals or future collaborations. For further information please contact the principal investigator, Dr Robert Hogg (robert_hogg@sfu.ca). PMID:24639444

The Initiation of Homeless Youth into the Street Economy

ERIC Educational Resources Information Center

Gwadz, Marya Viorst; Gostnell, Karla; Smolenski, Carol; Willis, Brian; Nish, David; Nolan, Theresa C.; Tharaken, Maya; Ritchie, Amanda S.

2009-01-01

Homeless youth (HY) who lack employment in the formal economy typically turn to the street economy (e.g., prostitution, drug selling) for survival. Guided by the theory of social control, the present paper explores factors influencing HY's initiation into the street economy. Eighty HY (ages 15-23) were recruited from four community-based…

Timely initiation of breastfeeding and associated factors among mothers of infants under 12 months in South Gondar zone, Amhara regional state, Ethiopia; 2013.

PubMed

Mekonen, Liyew; Seifu, Wubareg; Shiferaw, Zemenu

2018-01-01

Timely initiation of breastfeeding is defined as putting the newborn to the breast within one hour of birth. Significant benefits in reducing neonatal mortality and morbidity can be attained with effective promotion of timely initiation of breastfeeding and exclusive breastfeeding during the first months of life. Therefore, this study was conducted to assess timely initiation of breastfeeding and associated factors among mothers in South Gondar, Amhara regional state, Northern Ethiopia. A community based cross-sectional study was employed. A multistage stratified sampling technique was used to select the sample of 845 mothers with 97.4% response rate. Moreover, data were collected by face to face interview using a semi structured questionnaire. The prevalence of timely initiation of breastfeeding was 48.7% (54.7% in urban and 25.1% in rural areas). The odds of initiation of breastfeeding within one hour was higher for urban mothers (Adjusted Odds Ratio [AOR] 2.1; 95% Confidence Interval [CI] 1.4, 3.3), multiparous mothers (AOR 2.8; 95% CI 2.0, 3.8), mothers who had antenatal care (AOR 3.2; 95% CI 2.0, 5.2), mothers delivered in health institution (AOR 3.1; 95% CI 2.2, 4.6) and mothers delivered vaginally (AOR 4.1; 95% CI 1.7, 9.8) than their respective counterparts. This study depicts the rate of timely initiation of breastfeeding was low in south Gondar zone. Factors which were positively associated with timely initiation of breastfeeding include urban residence, multiparity, having antenatal care, mother deliver in health institution and vaginal mode of delivery. Therefore, South Gondar health office and healthcare providers have to provide breastfeeding information during antenatal care by giving special emphasis to rural and primiparous mothers in which timely initiation of breastfeeding is poorly practiced. Further study is needed to assess the implementation of policies on timely initiation of breastfeeding.

Designing for Learner Success (D4LS) at Otago Polytechnic: From an E-learning Designer's Perspective

ERIC Educational Resources Information Center

Gedera, Dilani S. P.

2016-01-01

Otago Polytechnic (OP) is currently redesigning and redeveloping its programmes and courses under an institution-wide initiative called Designing for Learner Success (D4LS). This initiative has several phases--design, development, delivery, and evaluation. This article focuses on the processes and considerations in the development phase of D4LS,…

The predictive role of E/e' on ischemic stroke and atrial fibrillation in Japanese patients without atrial fibrillation.

PubMed

Arai, Riku; Suzuki, Shinya; Semba, Hiroaki; Arita, Takuto; Yagi, Naoharu; Otsuka, Takayuki; Sagara, Koichi; Sasaki, Kenichi; Kano, Hiroto; Matsuno, Shunsuke; Kato, Yuko; Uejima, Tokuhisa; Oikawa, Yuji; Kunihara, Takashi; Yajima, Junji; Yamashita, Takeshi

2018-07-01

The predictive role of E/e' on ischemic stroke (IS) and atrial fibrillation (AF) in Japanese patients without AF are unclear. Shinken database includes all the new patients visiting the Cardiovascular Institute Hospital in Tokyo, Japan. E/e' has been routinely measured since 2007. Patients without AF for whom E/e' was measured at the initial visit between 2007 and 2014 (n=11 477, mean age 57.2 years old, men 59.5%) were divided into E/e' tertiles (<8.04, 8.04-11.00, >11.00). During the mean follow-up period of 1.8 years, 58 IS and 140 new appearances of AF were observed. High E/e' tertile was associated with more prevalence of atherothrombotic risks. The cumulative incidence of IS events and new appearance of AF at 6 years in low, middle, and high E/e' tertiles were 0.5%, 1.4%, and 3.0%/year (log-rank test, p<0.001), and 2.5%, 2.9%, and 4.2%/year (log-rank test, p=0.007), respectively. In multivariate analysis, high E/e' tertile was independently associated with IS (HR, 2.857, 95%CI 1.257-6.495, p=0.012). Although high E/e' tertile was independently associated with new appearance of AF when adjusted for coexistence of atherothrombotic risk factors (HR, 1.694, 95%CI, 1.097-2.616, p=0.017), the association was attenuated after adjustment for left atrial dimension. E/e' was significantly associated with incidence of IS and new appearance of AF in non-AF patients. Copyright © 2018 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

Short- and long-term effects of leucine and branched-chain amino acid supplementation of a protein- and energy-reduced diet on muscle protein metabolism in neonatal pigs.

PubMed

Manjarín, Rodrigo; Columbus, Daniel A; Solis, Jessica; Hernandez-García, Adriana D; Suryawan, Agus; Nguyen, Hanh V; McGuckin, Molly M; Jimenez, Rafael T; Fiorotto, Marta L; Davis, Teresa A

2018-05-04

The objective of this study was to determine if enteral leucine or branched-chain amino acid (BCAA) supplementation increases muscle protein synthesis in neonates who consume less than their protein and energy requirements, and whether this increase is mediated via the upregulation of the mechanistic target of rapamycin complex 1 (mTORC1) pathway or the decrease in muscle protein degradation signaling. Neonatal pigs were fed milk replacement diets containing reduced energy and protein (R), R supplemented with BCAA (RBCAA), R supplemented with leucine (RL), or complete protein and energy (CON) at 4-h intervals for 9 (n = 24) or 21 days (n = 22). On days 9 and 21, post-prandial plasma amino acids and insulin were measured at intervals for 4 h; muscle protein synthesis rate and activation of mTOR-related proteins were determined at 120 min post-feeding in muscle. For all parameters measured, the effects of diet were not different between day 9 or day 21. Compared to CON and R, plasma leucine and BCAA were higher (P ≤ 0.01) in RL- and RBCAA-fed pigs, respectively. Body weight gain, protein synthesis, and activation of S6 kinase (S6K1), 4E-binding protein (4EBP1), and eukaryotic initiation factor 4 complex (eIF4E·eIF4G) were decreased in RBCAA, RL, and R relative to CON (P < 0.01). RBCAA and RL upregulated (P ≤ 0.01) S6K1, 4EBP1, and eIF4E·eIF4G compared to R. In conclusion, when protein and energy are restricted, both leucine and BCAA supplementation increase mTOR activation, but do not enhance skeletal muscle protein synthesis and muscle growth in neonatal pigs.

Risk factors for tuberculosis treatment failure, default, or relapse and outcomes of retreatment in Morocco

PubMed Central

2011-01-01

Background Patients with tuberculosis require retreatment if they fail or default from initial treatment or if they relapse following initial treatment success. Outcomes among patients receiving a standard World Health Organization Category II retreatment regimen are suboptimal, resulting in increased risk of morbidity, drug resistance, and transmission.. In this study, we evaluated the risk factors for initial treatment failure, default, or early relapse leading to the need for tuberculosis retreatment in Morocco. We also assessed retreatment outcomes and drug susceptibility testing use for retreatment patients in urban centers in Morocco, where tuberculosis incidence is stubbornly high. Methods Patients with smear- or culture-positive pulmonary tuberculosis presenting for retreatment were identified using clinic registries in nine urban public clinics in Morocco. Demographic and outcomes data were collected from clinical charts and reference laboratories. To identify factors that had put these individuals at risk for failure, default, or early relapse in the first place, initial treatment records were also abstracted (if retreatment began within two years of initial treatment), and patient characteristics were compared with controls who successfully completed initial treatment without early relapse. Results 291 patients presenting for retreatment were included; 93% received a standard Category II regimen. Retreatment was successful in 74% of relapse patients, 48% of failure patients, and 41% of default patients. 25% of retreatment patients defaulted, higher than previous estimates. Retreatment failure was most common among patients who had failed initial treatment (24%), and default from retreatment was most frequent among patients with initial treatment default (57%). Drug susceptibility testing was performed in only 10% of retreatment patients. Independent risk factors for failure, default, or early relapse after initial treatment included male gender (aOR = 2.29, 95% CI 1.10-4.77), positive sputum smear after 3 months of treatment (OR 7.14, 95% CI 4.04-13.2), and hospitalization (OR 2.09, 95% CI 1.01-4.34). Higher weight at treatment initiation was protective. Male sex, substance use, missed doses, and hospitalization appeared to be risk factors for default, but subgroup analyses were limited by small numbers. Conclusions Outcomes of retreatment with a Category II regimen are suboptimal and vary by subgroup. Default among patients receiving tuberculosis retreatment is unacceptably high in urban areas in Morocco, and patients who fail initial tuberculosis treatment are at especially high risk of retreatment failure. Strategies to address risk factors for initial treatment default and to identify patients at risk for failure (including expanded use of drug susceptibility testing) are important given suboptimal retreatment outcomes in these groups. PMID:21356062

Risk factors for tuberculosis treatment failure, default, or relapse and outcomes of retreatment in Morocco.

PubMed

Dooley, Kelly E; Lahlou, Ouafae; Ghali, Iraqi; Knudsen, Janine; Elmessaoudi, My Driss; Cherkaoui, Imad; El Aouad, Rajae

2011-02-28

Patients with tuberculosis require retreatment if they fail or default from initial treatment or if they relapse following initial treatment success. Outcomes among patients receiving a standard World Health Organization Category II retreatment regimen are suboptimal, resulting in increased risk of morbidity, drug resistance, and transmission.. In this study, we evaluated the risk factors for initial treatment failure, default, or early relapse leading to the need for tuberculosis retreatment in Morocco. We also assessed retreatment outcomes and drug susceptibility testing use for retreatment patients in urban centers in Morocco, where tuberculosis incidence is stubbornly high. Patients with smear- or culture-positive pulmonary tuberculosis presenting for retreatment were identified using clinic registries in nine urban public clinics in Morocco. Demographic and outcomes data were collected from clinical charts and reference laboratories. To identify factors that had put these individuals at risk for failure, default, or early relapse in the first place, initial treatment records were also abstracted (if retreatment began within two years of initial treatment), and patient characteristics were compared with controls who successfully completed initial treatment without early relapse. 291 patients presenting for retreatment were included; 93% received a standard Category II regimen. Retreatment was successful in 74% of relapse patients, 48% of failure patients, and 41% of default patients. 25% of retreatment patients defaulted, higher than previous estimates. Retreatment failure was most common among patients who had failed initial treatment (24%), and default from retreatment was most frequent among patients with initial treatment default (57%). Drug susceptibility testing was performed in only 10% of retreatment patients. Independent risk factors for failure, default, or early relapse after initial treatment included male gender (aOR = 2.29, 95% CI 1.10-4.77), positive sputum smear after 3 months of treatment (OR 7.14, 95% CI 4.04-13.2), and hospitalization (OR 2.09, 95% CI 1.01-4.34). Higher weight at treatment initiation was protective. Male sex, substance use, missed doses, and hospitalization appeared to be risk factors for default, but subgroup analyses were limited by small numbers. Outcomes of retreatment with a Category II regimen are suboptimal and vary by subgroup. Default among patients receiving tuberculosis retreatment is unacceptably high in urban areas in Morocco, and patients who fail initial tuberculosis treatment are at especially high risk of retreatment failure. Strategies to address risk factors for initial treatment default and to identify patients at risk for failure (including expanded use of drug susceptibility testing) are important given suboptimal retreatment outcomes in these groups.

Non-equilibrium effects in steady relativistic e^+e^-gamma winds

NASA Astrophysics Data System (ADS)

Grimsrud, Ole M.; Wasserman, Ira

1998-11-01

We consider an ultrarelativistic wind consisting of electron-positron pairs and photons with the principal goal of finding the asymptotic Lorentz factor gamma_∞ for zero baryon number. The wind is assumed to originate at radius r_i where it has a Lorentz factor gamma_i and a temperature T_i sufficiently high to maintain pair equilibrium. As r increases, T decreases and becomes less than the temperature corresponding to the electron mass m_e, after which non-equilibrium effects become important. The pairs, which carry only a small fraction of the total energy, may be accelerated by the photons until tau falls below ~2x10^-5gamma^3/4_i. Radiative transfer calculations show that only at this point do the radiation flux and pressure start to deviate significantly from their blackbody values. The acceleration of the pairs increases gamma by a factor ~45 compared with its value at the photosphere; it is shown to approach gamma_∞~1.4x10^3(r^6_i/10cm)^1/4gamma^{3/4}_iT_i/m_e. The limit of zero baryon number is a good approximation when the mass injection rate Msolar in the flow is below a critical value corresponding to (Esolar/MsolarM)_c,0~5x10^7(r^6_i/10cm)T_i/m_e for fixed energy injection rate E/E. For large baryon loading, (Esolar/Msolar<~Esolar/Msolar)_c,M~350(r_i/10^6cm)^1/4gamma^3/4_iT_i/ m_e, the asymptotic Lorentz factor is gamma_∞~Esolar/Msolar. Surprisingly, increasing Esolar/Msolar from (Esolar/Msolar)_c,M to ∞ only increases gamma_∞ by a factor ~(m_p/m_e)^1/4~6.5, less than an order of magnitude. As Esolar/Msolar increases, the fraction of the energy carried by pairs decreases, reaching ~10^-5gamma^3/4_i as Esolar/Msolar to ∞.

e-Healthcare in India: critical success factors for sustainable health systems.

PubMed

Taneja, Udita; Sushil

2007-01-01

As healthcare enterprises seek to move towards an integrated, sustainable healthcare delivery model an IT-enabled or e-Healthcare strategy is being increasingly adopted. In this study we identified the critical success factors influencing the effectiveness of an e-Healthcare strategy in India. The performance assessment criteria used to measure effectiveness were increasing reach and reducing cost of healthcare delivery. A survey of healthcare providers was conducted. Analytic Hierarchy Process (AHP) and Interpretive Structural Modeling (ISM) were the analytical tools used to determine the relative importance of the critical success factors in influencing effectiveness of e-Healthcare and their interplay with each other. To succeed in e-Healthcare initiatives the critical success factors that need to be in place are appropriate government policies, literacy levels, and telecommunications and power infrastructure in the country. The focus should not be on the IT tools and biomedical engineering technologies as is most often the case. Instead the nontechnology factors such as healthcare provider and consumer mindsets should be addressed to increase acceptance of, and enhance the effectiveness of, sustainable e-Healthcare services.

Lack of pre-antiretroviral care and competition from traditional healers, crucial risk factors for very late initiation of antiretroviral therapy for HIV--a case-control study from eastern Uganda.

PubMed

Muhamadi, Lubega; Tumwesigye, Nazarius Mbona; Kadobera, Daniel; Marrone, Gaetano; Wabwire-Mangen, Fred; Pariyo, George; Peterson, Stefan; Ekström, Anna Mia

2011-01-01

Although WHO recommends starting antiretroviral treatment at a CD4 count of 350 cells/[µ]L, many Ugandan districts still struggle with large proportions of clients initiating ART very late at CD4<50 cells/[µ]L. This study seeks to establish crucial risk factors for very late ART initiation in eastern Uganda. All adult HIV-infected clients on ART in Iganga who enrolled between 2005 and 2009 were eligible for this case-control study. Clients who started ART at CD4 cell count of <50 cells/[µ]L (very late initiators) were classified as cases and 50-200 cells/[µ]L (late initiators) as control subjects. A total of 152 cases and 202 controls were interviewed. Multivariate analyses were performed to calculate adjusted odds ratios and 95% confidence intervals. Reported health system-related factors associated with very late ART initiation were stock-outs of antiretroviral drugs stock-outs (affecting 70% of the cases and none of the controls), competition from traditional/spiritual healers (AOR 7.8, 95 CI% 3.7-16.4), and lack of pre-ARV care (AOR 4.6, 95% CI: 2.3-9.3). Men were 60% more likely and subsistence farmers six times more likely (AOR 6.3, 95% CI: 3.1-13.0) to initiate ART very late. Lack of family support tripled the risk of initiating ART very late (AOR 3.3, 95% CI: 1.6-6.6). Policy makers should prevent ARV stock-outs though effective ARV procurement and supply chain management. New HIV clients should seek pre-ARV care for routine monitoring and determination of ART eligibility. ART services should be more affordable, accessible and user-friendly to make them more attractive than traditional healers.

HCV-like IRESs displace eIF3 to gain access to the 40S subunit

PubMed Central

Hashem, Yaser; des Georges, Amedee; Dhote, Vidya; Langlois, Robert; Liao, Hstau Y.; Grassucci, Robert A.; Pestova, Tatyana V.; Hellen, Christopher U.T.; Frank, Joachim

2014-01-01

Hepatitis C virus (HCV) and Classical swine fever virus (CSFV) mRNAs contain related (HCV-like) internal ribosome entry sites (IRESs) that promote 5’-end independent initiation of translation, requiring only a subset of the eukaryotic initiation factors (eIFs) needed for canonical initiation on cellular mRNAs1. Initiation on HCV-like IRESs relies on their specific interaction with the 40S subunit2–8, which places the initiation codon into the P site, where it directly base-pairs with eIF2-bound Met-tRNAiMet to form a 48S initiation complex. However, all HCV-like IRESs also specifically interact with eIF32,5–7,9–12, but the role of this interaction in IRES-mediated initiation has remained unknown. During canonical initiation, eIF3 binds to the 40S subunit as a component of the 43S pre-initiation complex, and comparison of the ribosomal positions of eIF313 and the HCV IRES8 revealed that they overlap, so that their rearrangement would be required for formation of ribosomal complexes containing both components13. Here, we present a cryo-electron microscopy reconstruction of a 40S ribosomal complex containing eIF3 and the CSFV IRES. Strikingly, although the position and interactions of the CSFV IRES with the 40S subunit in this complex are similar to those of the HCV IRES in the 40S/IRES binary complex8, eIF3 is completely displaced from its ribosomal position in the 43S complex, and instead interacts through its ribosome-binding surface exclusively with the apical region of domain III of the IRES. Our results suggest a role for the specific interaction of HCV-like IRESs with eIF3 in preventing ribosomal association of eIF3, which could serve two purposes: relieving the competition between the IRES and eIF3 for a common binding site on the 40S subunit, and reducing formation of 43S complexes, thereby favoring translation of viral mRNAs. PMID:24185006

Electronic Cigarette Use among Mississippi Adults, 2015.

PubMed

Mendy, Vincent L; Vargas, Rodolfo; Cannon-Smith, Gerri; Payton, Marinelle; Byambaa, Enkhmaa; Zhang, Lei

2017-01-01

Electronic cigarettes (e-cigarettes) are battery-powered devices that deliver nicotine in the form of aerosol. We identify differences and associations in e-cigarette use by sociodemographic characteristics and describe the reported reasons for initiating use among Mississippi adults. We used the 2015 Mississippi Behavioral Risk Factor Surveillance System, which collected information on e-cigarette use from 6,035 respondents. The prevalence of current e-cigarette use and having ever tried an e-cigarette was determined overall and by sociodemographic characteristics. Weighted prevalences and 95% confidence intervals were calculated, and prevalences for subgroups were compared using the X 2 tests and associations were assessed using logistic regression. In 2015, 4.7% of Mississippi adults currently used e-cigarettes, while 20.5% had ever tried an e-cigarette. The prevalence of current e-cigarette use was significantly higher for young adults, whites, men, individuals unable to work, those with income $35,000-$49,999, and current smokers compared to their counterparts. Similar results were observed for having ever tried an e-cigarette. E-cigarette use was associated with age, race, income, and smoking status. Most (71.2%) of current e-cigarette users and over half (52.1%) of those who have ever tried e-cigarettes reported that a main reason for trying or using e-cigarettes was "to cut down or quit smoking."

ONC201 kills solid tumor cells by triggering an integrated stress response dependent on ATF4 activation by specific eIF2α kinases.

PubMed

Kline, C Leah B; Van den Heuvel, A Pieter J; Allen, Joshua E; Prabhu, Varun V; Dicker, David T; El-Deiry, Wafik S

2016-02-16

ONC201 (also called TIC10) is a small molecule that inactivates the cell proliferation- and cell survival-promoting kinases Akt and ERK and induces cell death through the proapoptotic protein TRAIL. ONC201 is currently in early-phase clinical testing for various malignancies. We found through gene expression and protein analyses that ONC201 triggered an increase in TRAIL abundance and cell death through an integrated stress response (ISR) involving the transcription factor ATF4, the transactivator CHOP, and the TRAIL receptor DR5. ATF4 was not activated in ONC201-resistant cancer cells, and in ONC201-sensitive cells, knockdown of ATF4 or CHOP partially abrogated ONC201-induced cytotoxicity and diminished the ONC201-stimulated increase in DR5 abundance. The activation of ATF4 in response to ONC201 required the kinases HRI and PKR, which phosphorylate and activate the translation initiation factor eIF2α. ONC201 rapidly triggered cell cycle arrest, which was associated with decreased abundance of cyclin D1, decreased activity of the kinase complex mTORC1, and dephosphorylation of the retinoblastoma (Rb) protein. The abundance of X-linked inhibitor of apoptosis protein (XIAP) negatively correlated with the extent of apoptosis in response to ONC201. These effects of ONC201 were independent of whether cancer cells had normal or mutant p53. Thus, ONC201 induces cell death through the coordinated induction of TRAIL by an ISR pathway. Copyright © 2016, American Association for the Advancement of Science.

ONC201 kills solid tumor cells by triggering an integrated stress response dependent on ATF4 activation by specific eIF2α kinases

PubMed Central

Kline, C. Leah B.; Van den Heuvel, A. Pieter J.; Allen, Joshua E.; Prabhu, Varun V.; Dicker, David T.; El-Deiry, Wafik S.

2016-01-01

ONC201 (also called TIC10) is a small molecule that inactivates the cell proliferation- and cell survival-promoting kinases AKT and ERK and induces cell death through the pro-apoptotic protein TRAIL. ONC201 is currently in early phase clinical testing for various malignancies. Here, we found through gene expression and protein analyses that ONC201 triggered an increase in TRAIL abundance and cell death through an integrated stress response (ISR) involving the transcription factor ATF4, the transactivator CHOP, and the TRAIL receptor DR5. ATF4 was not activated in ONC201-resistant cancer cells, and in ONC201-sensitive cells, knockdown of ATF4 or CHOP partially abrogated ONC201-induced cytotoxicity and diminished the ONC201-stimulated increase in DR5 abundance. The activation of ATF4 in response to ONC201 required the kinases HRI and PKR, which phosphorylate and activate the translation initiation factor eIF2α. ONC201 rapidly triggered cell cycle arrest, which was associated with decreased abundance of cyclin D1, decreased activity of the kinase complex mTORC1, and dephosphorylation of the retinoblastoma (Rb) protein. The abundance of X-linked inhibitor of apoptosis protein (XIAP) negatively correlated with the extent of apoptosis in response to ONC201. These effects of ONC201 were independent of whether cancer cells had normal or mutant p53. Thus, ONC201 induces cell death through the coordinated induction of TRAIL by an ISR pathway. PMID:26884600

Mitochondrial Respiration Inhibitors Suppress Protein Translation and Hypoxic Signaling via the Hyperphosphorylation and Inactivation of Translation Initiation Factor eIF2α and Elongation Factor eEF2

PubMed Central

Li, Jun; Mahdi, Fakhri; Du, Lin; Datta, Sandipan; Nagle, Dale G.; Zhou, Yu-Dong

2011-01-01

Over 20000 lipid extracts of plants and marine organisms were evaluated in a human breast tumor T47D cell-based reporter assay for hypoxia-inducible factor-1 (HIF-1) inhibitory activity. Bioassay-guided isolation and dereplication-based structure elucidation of an active extract from the Bael tree (Aegle marmelos) afforded two protolimonoids, skimmiarepin A (1) and skimmiarepin C (2). In T47D cells, 1 and 2 inhibited hypoxia-induced HIF-1 activation with IC50 values of 0.063 µM and 0.068 µM, respectively. Compounds 1 and 2 also suppressed hypoxic induction of the HIF-1 target genes GLUT-1 and VEGF. Mechanistic studies revealed that 1 and 2 inhibited HIF-1 activation by blocking the hypoxia-induced accumulation of HIF-1α protein. At the range of concentrations that inhibited HIF-1 activation, 1 and 2 suppressed cellular respiration by selectively inhibiting the mitochondrial electron transport chain at complex I (NADH dehydrogenase). Further investigation indicated that mitochondrial respiration inhibitors such as 1 and rotenone induced the rapid hyperphosphorylation and inhibition of translation initiation factor eIF2α and elongation factor eEF2. The inhibition of protein translation may account for the short-term exposure effects exerted by mitochondrial inhibitors on cellular signaling, while the suppression of cellular ATP production may contribute to the inhibitory effects following extended treatment periods. PMID:21875114

Altered macrophage arachidonic acid metabolism induced by endotoxin tolerance: characterization and mechanisms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rogers, T.S.

Altered macrophage arachidonic acid (AA) metabolism may play a role in endotoxic shock and the phenomenon of endotoxin tolerance induced by repeated injections of endotoxin. Studies were initiated to characterize both lipoxygenase and cyclooxygenase metabolite formation by endotoxin tolerant and non-tolerant macrophages in response to 4 different stimuli, i.e., endotoxin, glucan, zymosan, and the calcium ionophore A23187. In contrast to previous reports of decreased prostaglandin synthesis by tolerant macrophages, A23187-stimulated immunoreactive (i) leukotriene (LT) C/sub 4/D/sub 4/ and prostaglandin (PG) E/sub 2/ production by tolerant cells was greater than that by non-tolerant controls (p <0.001). However, A23187-stimulated i6-keto PGF/sub 1a/more » levels were lower in tolerant macrophages compared to controls (P < 0.05). iL TC/sub 4/D/sub 4/ production was not significantly stimulated by endotoxin or glucan, but was stimulated by zymosan in non-tolerant cells. Synthesis of iLTB/sub 4/ by control macrophages was stimulated by endotoxin (p <0.01). The effect of tolerance on factors that affect AA release was investigated by measuring /sup 14/C-AA incorporation and release and phospholipase A/sub 2/ activity« less

Long-term effect of increased lead absorption on intelligence of children.

PubMed

Soong, W T; Chao, K Y; Jang, C S; Wang, J D

1999-01-01

The authors examined the reversibility of cognitive impairment caused by a mild increase in lead absorption among children. The results of our initial study revealed that air and soil outside a lead-recycling plant in Taiwan were seriously contaminated by lead, which was associated with lowered intelligence quotients of 32 children who attended a nearby kindergarten (i.e., kindergarten A). Thirty-five children-who were comparable with respect to age, sex, birth order, sibling number, and parental education level-from another kindergarten (i.e., kindergarten B) located 5 km from the plant were enrolled as the reference group. Following the initial study, kindergarten A school children moved 2 km from the lead-recycling plant. Twenty-eight children in each group were followed successfully 2.5 y later. Blood lead, intelligence quotient, and intelligence quotient-related factors were reassessed. The results showed that the average blood lead level of the exposed pupils dropped 6.9 microg/dl (standard deviation [SD] = 3.9 microg/dl) (p < .001), and the average intelligence quotient increased 11.7 points (SD = 13.2) (p < .01), compared with the results of the initial study. The average blood lead level of the reference group decreased by 1.7 microg/dl (SD = .1.3) (p < .001), whereas the average intelligence quotient increased by 4.2 points (SD = 13.8) (p = .115). There was a significant difference in intelligence quotients between the two groups during the initial study, but the difference subsequently disappeared during the follow up. The authors concluded that intelligence quotient impairment, caused by a mild subclinical elevation of blood lead (i.e., likely no more than 30 microg/dl) for a period of 1-3 y in 3- to 5-y-olds, is at least partially reversible.

Obesity challenges the hepatoprotective function of the integrated stress response to asparaginase exposure in mice.

PubMed

Nikonorova, Inna A; Al-Baghdadi, Rana J T; Mirek, Emily T; Wang, Yongping; Goudie, Michael P; Wetstein, Berish B; Dixon, Joseph L; Hine, Christopher; Mitchell, James R; Adams, Christopher M; Wek, Ronald C; Anthony, Tracy G

2017-04-21

Obesity increases risk for liver toxicity by the anti-leukemic agent asparaginase, but the mechanism is unknown. Asparaginase activates the integrated stress response (ISR) via sensing amino acid depletion by the eukaryotic initiation factor 2 (eIF2) kinase GCN2. The goal of this work was to discern the impact of obesity, alone versus alongside genetic disruption of the ISR, on mechanisms of liver protection during chronic asparaginase exposure in mice. Following diet-induced obesity, biochemical analysis of livers revealed that asparaginase provoked hepatic steatosis that coincided with activation of another eIF2 kinase PKR-like endoplasmic reticulum kinase (PERK), a major ISR transducer to ER stress. Genetic loss of Gcn2 intensified hepatic PERK activation to asparaginase, yet surprisingly, mRNA levels of key ISR gene targets such as Atf5 and Trib3 failed to increase. Instead, mechanistic target of rapamycin complex 1 (mTORC1) signal transduction was unleashed, and this coincided with liver dysfunction reflected by a failure to maintain hydrogen sulfide production or apolipoprotein B100 (ApoB100) expression. In contrast, obese mice lacking hepatic activating transcription factor 4 ( Atf4 ) showed an exaggerated ISR and greater loss of endogenous hydrogen sulfide but normal inhibition of mTORC1 and maintenance of ApoB100 during asparaginase exposure. In both genetic mouse models, expression and phosphorylation of Sestrin2, an ATF4 gene target, was increased by asparaginase, suggesting mTORC1 inhibition during asparaginase exposure is not driven via eIF2-ATF4-Sestrin2. In conclusion, obesity promotes a maladaptive ISR during asparaginase exposure. GCN2 functions to repress mTORC1 activity and maintain ApoB100 protein levels independently of Atf4 expression, whereas hydrogen sulfide production is promoted via GCN2-ATF4 pathway. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Functional assembly of intrinsic coagulation proteases on monocytes and platelets. Comparison between cofactor activities induced by thrombin and factor Xa

PubMed Central

1992-01-01

Generation of coagulation factor Xa by the intrinsic pathway protease complex is essential for normal activation of the coagulation cascade in vivo. Monocytes and platelets provide membrane sites for assembly of components of this protease complex, factors IXa and VIII. Under biologically relevant conditions, expression of functional activity by this complex is associated with activation of factor VIII to VIIIa. In the present studies, autocatalytic regulatory pathways operating on monocyte and platelet membranes were investigated by comparing the cofactor function of thrombin-activated factor VIII to that of factor Xa-activated factor VIII. Reciprocal functional titrations with purified human factor VIII and factor IXa were performed at fixed concentrations of human monocytes, CaCl2, factor X, and either factor IXa or factor VIII. Factor VIII was preactivated with either thrombin or factor Xa, and reactions were initiated by addition of factor X. Rates of factor X activation were measured using chromogenic substrate specific for factor Xa. The K1/2 values, i.e., concentration of factor VIIIa at which rates were half maximal, were 0.96 nM with thrombin- activated factor VIII and 1.1 nM with factor Xa-activated factor VIII. These values are close to factor VIII concentration in plasma. The Vsat, i.e., rates at saturating concentrations of factor VIII, were 33.3 and 13.6 nM factor Xa/min, respectively. The K1/2 and Vsat values obtained in titrations with factor IXa were not significantly different from those obtained with factor VIII. In titrations with factor X, the values of Michaelis-Menten coefficients (Km) were 31.7 nM with thrombin- activated factor VIII, and 14.2 nM with factor Xa-activated factor VIII. Maximal rates were 23.4 and 4.9 nM factor Xa/min, respectively. The apparent catalytic efficiency was similar with either form of factor VIIIa. Kinetic profiles obtained with platelets as a source of membrane were comparable to those obtained with monocytes. These kinetic profiles are consistent with a 1:1 stoichiometry for the functional interaction between cofactor and enzyme on the surface of monocytes and platelets. Taken together, these results indicate that autocatalytic pathways connecting the extrinsic, intrinsic, and common coagulation pathways can operate efficiently on the monocyte membrane. PMID:1613461

The SIRT1 inhibitor EX-527 suppresses mTOR activation and alleviates acute lung injury in mice with endotoxiemia.

PubMed

Huang, Jing; Tian, Rui; Yang, Yongqiang; Jiang, Rong; Dai, Jie; Tang, Li; Zhang, Li

2017-11-01

It is generally regarded that Sirtuin 1 (SIRT1), a longevity factor in mammals, acts as a negative regulator of inflammation. However, recent studies also found that SIRT1 might be a detrimental factor under certain inflammatory circumstance. In this study, the potential pathophysiological roles and the underlying mechanisms of SIRT1 in a mouse model with endotoxemia-associated acute lung injury were investigated. The results indicated that treatment with the selective SIRT1 inhibitor EX-527 suppressed LPS-induced elevation of TNF-α and IL-6 in plasma. Treatment with EX-527 attenuated LPS-induced histological abnormalities in lung tissue, which was accompanied with decreased myeloperoxidase level and suppressed induction of tissue factor and plasminogen activator inhibitor-1. Treatment with EX-527 also suppressed LPS-induced phosphorylation of eukaryotic translation initiation factor-binding protein 1 (4E-BP1). Co-administration of a mammalian target of rapamycin (mTOR) activator 3-benzyl-5-[(2-nitrophenoxy) methyl]-dihydrofuran-2 (3H)-one (3BDO) abolished the inhibitory effects of EX-527 on 4E-BP1 phosphorylation. Meanwhile, the inhibitory effects of EX-527 on IL-6 induction and the beneficial effects of EX-527 on lung injury were partially reversed by 3BDO. This study suggests that selective inhibition of SIRT1 by EX-527 might alleviate endotoxemia-associated acute lung injury partially via suppression of mTOR, which implies that SIRT1 selective inhibitors might have potential value for the pharmacological intervention of inflammatory lung injury.

Content validity of critical success factors for e-Government implementation in Indonesia

NASA Astrophysics Data System (ADS)

Napitupulu, D.; Syafrullah, M.; Rahim, R.; Amar, A.; Sucahyo, YG

2018-05-01

The purpose of this research is to validate the Critical Success Factors (CSFs) of e-Government implementation in Indonesia. The e-Government initiative conducted only to obey the regulation but ignoring the quality. Defining CSFs will help government agencies to avoid failure of e-Government projects. A survey with the questionnaire was used to validate the item of CSF based on expert judgment through two round of Delphi. The result showed from 67 subjects in instrument tested; there are 11 invalid items deleted and remain only 56 items that had good content validity and internal reliability. Therefore, all 56 CSFs should be adopted by government agencies in Indonesia to support e-Government implementation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clayton, James; Shedlock, Daniel; Langeveld, Willem G.J.

Two goals for security scanning of cargo and freight are the ability to determine the type of material that is being imaged, and to do so at low radiation dose. One commonly used technique to determine the effective Z of the cargo is dual-energy imaging, i.e. imaging with different x-ray energy spectra. Another technique uses the fact that the transmitted x-ray spectrum itself also depends on the effective Z. Spectroscopy is difficult because the energy of individual x rays needs to be measured in a very high count-rate environment. Typical accelerators for security applications offer large but short bursts ofmore » x-rays, suitable for current-mode integrated imaging. In order to perform x-ray spectroscopy, a new accelerator design is desired that has the following features: 1) increased duty factor in order to spread out the arrival of x-rays at the detector array over time; 2) x-ray intensity modulation from one delivered pulse to the next by adjusting the accelerator electron beam instantaneous current so as to deliver adequate signal without saturating the spectroscopic detector; and 3) the capability to direct the (forward peaked) x-ray intensity towards high-attenuation areas in the cargo (“fan-beam-steering”). Current sources are capable of 0.1% duty factor, although usually they are operated at significantly lower duty factors (~0.04%), but duty factors in the range 0.4-1.0% are desired. The higher duty factor can be accomplished, e.g., by moving from 300 pulses per second (pps) to 1000 pps and/or increasing the pulse duration from a typical 4 μs to 10 μs. This paper describes initial R&D to examine cost effective modifications that could be performed on a typical accelerator for these purposes, as well as R&D for fan-beam steering.« less

Hypusine modification in eukaryotic initiation factor 5A in rodent cells selected for resistance to growth inhibition by ornithine decarboxylase-inhibiting drugs.

PubMed Central

Tome, M E; Gerner, E W

1996-01-01

Selection of HTC cells in drugs that inhibit ornithine decarboxylase (ODC) has produced two cell lines, HMOA and DH23A/b, that contain increased amounts of more stable ODC. In addition to alterations in ODC, these cells appear to produce modified eukaryotic initiation factor 5A (eIF-5A) at different rates, a reaction that both requires spermidine and is essential for proliferation. Alterations to the modification of eIF-5A by spermidine cannot be accounted for by changes in eIF-5A protein or modified eIF-5A turnover. Deoxyhypusine synthetase activity is similar in the parental and variant cell lines and is unaltered by growth into plateau phase or by spermidine depletion. The increased rate of eIF-5A modification in DH23A/b cells is due to an increased accumulation of the unmodified eIF-5A precursor. Increased precursor accumulation is not due to increased eIF-5A transcription, but rather it can be attributed to a metabolic accumulation caused by growth under conditions of chronically limiting spermidine. Selection using drugs that inhibit ODC apparently does not cause alterations in the eIF-5A modification pathway. These data support the hypothesis that one of the main effects of spermidine depletion is depletion of the modified eIF-5A pool, and that this is a critical factor in the cytostasis often observed after depletion of cellular polyamines. PMID:8947467

Induced phenylpropanoid metabolism during suberization and lignification: a comparative analysis

NASA Technical Reports Server (NTRS)

Bernards, M. A.; Susag, L. M.; Bedgar, D. L.; Anterola, A. M.; Lewis, N. G.

2000-01-01

Induction of the biosynthesis of phenylpropanoids was monitored at the enzyme level through measurement of the temporal change in the activity of two marker enzymes of phenylpropanoid metabolism, phenylalanine ammonia-lyase, (PAL, E.C. 4.1.3.5) and 4-coumaryl-CoA ligase (4-CL, E.C. 6.2.1.12) and two marker enzymes for hydroxycinnamyl alcohol biosynthesis, cinnamoyl-CoA:NADP+ oxidoreductase (CCR, E.C. 1.2.1.44) and cinnamyl alcohol dehydrogenase (CAD, E.C. 1.1.1.195) in both suberizing potato (Solanum tuberosum) tubers and lignifying loblolly pine (Pinus taeda) cell cultures. While measurable activities of PAL, 4-CL and CAD increased upon initiation of suberization in potato tubers, that of CCR did not. By contrast, all four enzymes were induced upon initiation of lignification in pine cell cultures. The lack of CCR induction in potato by wound treatment is consistent with the channelling of hydroxycinnamoyl-CoA derivatives away from monolignol formation and toward other hydroxycinnamoyl derivatives such as those that accumulate during suberization.

Foliar litter decomposition in an alpine forest meta-ecosystem on the eastern Tibetan Plateau.

PubMed

Yue, Kai; Yang, Wanqin; Peng, Changhui; Peng, Yan; Zhang, Chuan; Huang, Chunping; Tan, Yu; Wu, Fuzhong

2016-10-01

Litter decomposition is a biological process fundamental to element cycling and a main nutrient source within forest meta-ecosystems, but few studies have looked into this process simultaneously in individual ecosystems, where environmental factors can vary substantially. A two-year field study conducted in an alpine forest meta-ecosystem with four litter species (i.e., willow: Salix paraplesia, azalea: Rhododendron lapponicum, cypress: Sabina saltuaria, and larch: Larix mastersiana) that varied widely in chemical traits showed that both litter species and ecosystem type (i.e., forest floor, stream and riparian zone) are important factors affecting litter decomposition, and their effects can be moderated by local-scale environmental factors such as temperature and nutrient availability. Litter decomposed fastest in the streams followed by the riparian zone and forest floor regardless of species. For a given litter species, both the k value and limit value varied significantly among ecosystems, indicating that the litter decomposition rate and extent (i.e., reaching a limit value) can be substantially affected by ecosystem type and the local-scale environmental factors. Apart from litter initial acid unhydrolyzable residue (AUR) concentration and its ratio to nitrogen concentration (i.e., AUR/N ratio), the initial nutrient concentrations of phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) were also important litter traits that affected decomposition depending on the ecosystem type. Copyright © 2016 Elsevier B.V. All rights reserved.