The cytosolic tail of the Golgi apyrase Ynd1 mediates E4orf4-induced toxicity in Saccharomyces cerevisiae.

PubMed

Mittelman, Karin; Ziv, Keren; Maoz, Tsofnat; Kleinberger, Tamar

2010-11-22

The adenovirus E4 open reading frame 4 (E4orf4) protein contributes to regulation of the progression of virus infection. When expressed individually, E4orf4 was shown to induce non-classical transformed cell-specific apoptosis in mammalian cells. At least some of the mechanisms underlying E4orf4-induced toxicity are conserved from yeast to mammals, including the requirement for an interaction of E4orf4 with protein phosphatase 2A (PP2A). A genetic screen in yeast revealed that the Golgi apyrase Ynd1 associates with E4orf4 and contributes to E4orf4-induced toxicity, independently of Ynd1 apyrase activity. Ynd1 and PP2A were shown to contribute additively to E4orf4-induced toxicity in yeast, and to interact genetically and physically. A mammalian orthologue of Ynd1 was shown to bind E4orf4 in mammalian cells, confirming the evolutionary conservation of this interaction. Here, we use mutation analysis to identify the cytosolic tail of Ynd1 as the protein domain required for mediation of the E4orf4 toxic signal and for the interaction with E4orf4. We also show that E4orf4 associates with cellular membranes in yeast and is localized at their cytoplasmic face. However, E4orf4 is membrane-associated even in the absence of Ynd1, suggesting that additional membrane proteins may mediate E4orf4 localization. Based on our results and on a previous report describing a collection of Ynd1 protein partners, we propose that the Ynd1 cytoplasmic tail acts as a scaffold, interacting with a multi-protein complex, whose targeting by E4orf4 leads to cell death.

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

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

Multiple PAR and E4BP4 bZIP transcription factors in zebrafish: diverse spatial and temporal expression patterns.

PubMed

Ben-Moshe, Zohar; Vatine, Gad; Alon, Shahar; Tovin, Adi; Mracek, Philipp; Foulkes, Nicholas S; Gothilf, Yoav

2010-09-01

Circadian rhythms of physiology and behavior are generated by an autonomous circadian oscillator that is synchronized daily with the environment, mainly by light input. The PAR subfamily of transcriptional activators and the related E4BP4 repressor belonging to the basic leucine zipper (bZIP) family are clock-controlled genes that are suggested to mediate downstream circadian clock processes and to feedback onto the core oscillator. Here, the authors report the characterization of these genes in the zebrafish, an increasingly important model in the field of chronobiology. Five novel PAR and six novel e4bp4 zebrafish homolog genes were identified using bioinformatic tools and their coding sequences were cloned. Based on their evolutionary relationships, these genes were annotated as ztef2, zhlf1 and zhlf2, zdbp1 and zdbp2, and ze4bp4-1 to -6. The spatial and temporal mRNA expression pattern of each of these factors was characterized in zebrafish embryos in the context of a functional circadian clock and regulation by light. Nine of the factors exhibited augmented and rhythmic expression in the pineal gland, a central clock organ in zebrafish. Moreover, these genes were found to be regulated, to variable extents, by the circadian clock and/or by light. Differential expression patterns of multiple paralogs in zebrafish suggest multiple roles for these factors within the vertebrate circadian clock. This study, in the genetically accessible zebrafish model, lays the foundation for further research regarding the involvement and specific roles of PAR and E4BP4 transcription factors in the vertebrate circadian clock mechanism.

Structure of the eukaryotic translation initiation factor eIF4E in complex with 4EGI-1 reveals an allosteric mechanism for dissociating eIF4G.

PubMed

Papadopoulos, Evangelos; Jenni, Simon; Kabha, Eihab; Takrouri, Khuloud J; Yi, Tingfang; Salvi, Nicola; Luna, Rafael E; Gavathiotis, Evripidis; Mahalingam, Poornachandran; Arthanari, Haribabu; Rodriguez-Mias, Ricard; Yefidoff-Freedman, Revital; Aktas, Bertal H; Chorev, Michael; Halperin, Jose A; Wagner, Gerhard

2014-08-05

The interaction of the eukaryotic translation initiation factor eIF4E with the initiation factor eIF4G recruits the 40S ribosomal particle to the 5' end of mRNAs, facilitates scanning to the AUG start codon, and is crucial for eukaryotic translation of nearly all genes. Efficient recruitment of the 40S particle is particularly important for translation of mRNAs encoding oncoproteins and growth-promoting factors, which often harbor complex 5' UTRs and require efficient initiation. Thus, inhibiting the eIF4E/eIF4G interaction has emerged as a previously unpursued route for developing anticancer agents. Indeed, we discovered small-molecule inhibitors of this eIF4E/eIF4G interaction (4EGIs) that inhibit translation initiation both in vitro and in vivo and were used successfully in numerous cancer-biology and neurobiology studies. However, their detailed molecular mechanism of action has remained elusive. Here, we show that the eIF4E/eIF4G inhibitor 4EGI-1 acts allosterically by binding to a site on eIF4E distant from the eIF4G binding epitope. Data from NMR mapping and high-resolution crystal structures are congruent with this mechanism, where 4EGI-1 attaches to a hydrophobic pocket of eIF4E between β-sheet2 (L60-T68) and α-helix1 (E69-N77), causing localized conformational changes mainly in the H78-L85 region. It acts by unfolding a short 310-helix (S82-L85) while extending α-helix1 by one turn (H78-S82). This unusual helix rearrangement has not been seen in any previous eIF4E structure and reveals elements of an allosteric inhibition mechanism leading to the dislocation of eIF4G from eIF4E.

Loss of epigenetic Kruppel-like factor 4 histone deacetylase (KLF-4-HDAC)-mediated transcriptional suppression is crucial in increasing vascular endothelial growth factor (VEGF) expression in breast cancer.

PubMed

Ray, Alpana; Alalem, Mohamed; Ray, Bimal K

2013-09-20

Vascular endothelial growth factor (VEGF) is recognized as an important angiogenic factor that promotes angiogenesis in a series of pathological conditions, including cancer, inflammation, and ischemic disorders. We have recently shown that the inflammatory transcription factor SAF-1 is, at least in part, responsible for the marked increase of VEGF levels in breast cancer. Here, we show that SAF-1-mediated induction of VEGF is repressed by KLF-4 transcription factor. KLF-4 is abundantly present in normal breast epithelial cells, but its level is considerably reduced in breast cancer cells and clinical cancer tissues. In the human VEGF promoter, SAF-1- and KLF-4-binding elements are overlapping, whereas SAF-1 induces and KLF-4 suppresses VEGF expression. Ectopic overexpression of KLF-4 and RNAi-mediated inhibition of endogenous KLF-4 supported the role of KLF-4 as a transcriptional repressor of VEGF and an inhibitor of angiogenesis in breast cancer cells. We show that KLF-4 recruits histone deacetylases (HDACs) -2 and -3 at the VEGF promoter. Chronological ChIP assays demonstrated the occupancy of KLF-4, HDAC2, and HDAC3 in the VEGF promoter in normal MCF-10A cells but not in MDA-MB-231 cancer cells. Co-transfection of KLF-4 and HDAC expression plasmids in breast cancer cells results in synergistic repression of VEGF expression and inhibition of angiogenic potential of these carcinoma cells. Together these results identify a new mechanism of VEGF up-regulation in cancer that involves concomitant loss of KLF-4-HDAC-mediated transcriptional repression and active recruitment of SAF-1-mediated transcriptional activation.

High-methionine diets accelerate atherosclerosis by HHcy-mediated FABP4 gene demethylation pathway via DNMT1 in ApoE(-/-) mice.

PubMed

Yang, An-Ning; Zhang, Hui-Ping; Sun, Yue; Yang, Xiao-Ling; Wang, Nan; Zhu, Guangrong; Zhang, Hui; Xu, Hua; Ma, Sheng-Chao; Zhang, Yue; Li, Gui-Zhong; Jia, Yue-Xia; Cao, Jun; Jiang, Yi-Deng

2015-12-21

Homocysteine (Hcy) is an independent risk factor for atherosclerosis, but the underlying molecular mechanisms are not known. We investigated the effects of Hcy on fatty acid-binding protein 4 (FABP4), and tested our hypothesis that Hcy-induced atherosclerosis is mediated by increased FABP4 expression and decreased methylation. The FABP4 expression and DNA methylation was assessed in the aorta of ApoE(-/-) mice fed high-methionine diet for 20weeks. Over-expression of FABP4 enhanced accumulation of total cholesterol and cholesterol ester in foam cells. The up-regulation of DNA methyltransferase 1 (DNMT1) promoted the methylation process and decreased FABP4 expression. These data suggest that FABP4 plays a key role in Hcy-mediated disturbance of lipid metabolism and that DNMT1 may be a novel therapeutic target in Hcy-related atherosclerosis. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Impact of Patient-centered eHealth Applications on Patient Outcomes: A Review on the Mediating Influence of Human Factor Issues.

PubMed

Wildenbos, G A; Peute, L W; Jaspers, M W M

2016-11-10

To examine the evidence of the impact of patient- centered eHealth applications on patient care and to analyze if and how reported human factor issues mediated the outcomes. We searched PubMed (2014-2015) for studies evaluating the impact of patient-centered eHealth applications on patient care (behavior change, self-efficacy, and patient health-related outcomes). The Systems Engineering Initiative for Patient Safety (SEIPS 2.0) model was used as a guidance framework to identify the reported human factors possibly impacting the effectiveness of an eHealth intervention. Of the 348 potentially relevant papers, 10 papers were included for data analysis. None of the 10 papers reported a negative impact of the eHealth intervention. Seven papers involved a randomized controlled trial (RCT) study. Six of these RCTs reported a positive impact of the eHealth intervention on patient care. All 10 papers reported on human factor issues possibly mediating effects of patient-centered eHealth. Human factors involved patient characteristics, perceived social support, and (type of) interaction between patient and provider. While the amount of patient-centered eHealth interventions increases, many questions remain as to whether and to what extent human factors mediate their use and impact. Future research should adopt a formal theory-driven approach towards human factors when investigating those factors' influence on the effectiveness of these interventions. Insights could then be used to better tailor the content and design of eHealth solutions according to patient user profiles, so as to enhance eHealth interventions impact on patient behavior, self-efficacy, and health-related outcomes.

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

Transcription factor Sox4 is required for PUMA-mediated apoptosis induced by histone deacetylase inhibitor, TSA.

PubMed

Jang, Sang-Min; Kang, Eun-Jin; Kim, Jung-Woong; Kim, Chul-Hong; An, Joo-Hee; Choi, Kyung-Hee

2013-08-23

PUMA is a crucial regulator of apoptotic cell death mediated by p53-dependent and p53-independent mechanisms. In many cancer cells, PUMA expression is induced in response to DNA-damaging reagent in a p53-dependent manner. However, few studies have investigated transcription factors that lead to the induction of PUMA expression via p53-independent apoptotic signaling. In this study, we found that the transcription factor Sox4 increased PUMA expression in response to trichostatin A (TSA), a histone deacetylase inhibitor in the p53-null human lung cancer cell line H1299. Ectopic expression of Sox4 led to the induction of PUMA expression at the mRNA and protein levels, and TSA-mediated up-regulation of PUMA transcription was repressed by the knockdown of Sox4. Using luciferase assays and chromatin immunoprecipitation, we also determined that Sox4 recruits p300 on the PUMA promoter region and increases PUMA gene expression in response to TSA treatment. Taken together, these results suggest that Sox4 is required for p53-independent apoptotic cell death mediated by PUMA induction via TSA treatment. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

The effect of individual factors on health behaviors among college students: the mediating effects of eHealth literacy.

PubMed

Hsu, WanChen; Chiang, ChiaHsun; Yang, ShuChing

2014-12-12

College students' health behavior is a topic that deserves attention. Individual factors and eHealth literacy may affect an individual's health behaviors. The integrative model of eHealth use (IMeHU) provides a parsimonious account of the connections among the digital divide, health care disparities, and the unequal distribution and use of communication technologies. However, few studies have explored the associations among individual factors, eHealth literacy, and health behaviors, and IMeHU has not been empirically investigated. This study examines the associations among individual factors, eHealth literacy, and health behaviors using IMeHU. The Health Behavior Scale is a 12-item instrument developed to measure college students' eating, exercise, and sleep behaviors. The eHealth Literacy Scale is a 12-item instrument designed to measure college students' functional, interactive, and critical eHealth literacy. A nationally representative sample of 525 valid college students in Taiwan was surveyed. A questionnaire was administered to collect background information about participants' health status, degree of health concern, major, and the frequency with which they engaged in health-related discussions. This study used Amos 6.0 to conduct a confirmatory factor analysis to identify the best measurement models for the eHealth Literacy Scale and the Health Behavior Scale. We then conducted a multiple regression analysis to examine the associations among individual factors, eHealth literacy, and health behaviors. Additionally, causal steps approach was used to explore indirect (mediating) effects and Sobel tests were used to test the significance of the mediating effects. The study found that perceptions of better health status (t520=2.14-6.12, P<.001-.03) and greater concern for health (t520=2.58-6.95, P<.001-.003) influenced college students' development of 3 dimensions of eHealth literacy and adoption of healthy eating, exercise, and sleep behaviors. Moreover, e

Rotenone Induction of Hydrogen Peroxide Inhibits mTOR-mediated S6K1 and 4E-BP1/eIF4E Pathways, Leading to Neuronal Apoptosis

PubMed Central

Zhou, Qian; Liu, Chunxiao; Liu, Wen; Zhang, Hai; Zhang, Ruijie; Liu, Jia; Zhang, Jinfei; Xu, Chong; Liu, Lei; Huang, Shile; Chen, Long

2015-01-01

Rotenone, a common pesticide and inhibitor of mitochondrial complex I, induces loss of dopaminergic neurons and consequential aspects of Parkinson’s disease (PD). However, the exact mechanism of rotenone neurotoxicity is not fully elucidated. Here, we show that rotenone induced reactive oxygen species (ROS), leading to apoptotic cell death in PC12 cells and primary neurons. Pretreatment with catalase (CAT), a hydrogen peroxide-scavenging enzyme, attenuated rotenone-induced ROS and neuronal apoptosis, implying hydrogen peroxide (H2O2) involved, which was further verified by imaging intracellular H2O2 using a peroxide-selective probe H2DCFDA. Using thenoyltrifluoroacetone (TTFA), antimycin A, or Mito-TEMPO, we further demonstrated rotenone-induced mitochondrial H2O2-dependent neuronal apoptosis. Rotenone dramatically inhibited mTOR-mediated phosphorylation of S6K1 and 4E-BP1, which was also attenuated by CAT in the neuronal cells. Of interest, ectopic expression of wild-type mTOR or constitutively active S6K1, or downregulation of 4E-BP1 partially prevented rotenone-induced H2O2 and cell apoptosis. Furthermore, we noticed that rotenone-induced H2O2 was linked to the activation of caspase-3 pathway. This was evidenced by the finding that pretreatment with CAT partially blocked rotenone-induced cleavages of caspase-3 and poly (ADP-ribose) polymerase. Of note, zVAD-fmk, a pan caspase inhibitor, only partially prevented rotenone-induced apoptosis in PC12 cells and primary neurons. Expression of mTOR-wt, S6K1-ca, or silencing 4E-BP1 potentiated zVAD-fmk protection against rotenone-induced apoptosis in the cells. The results indicate that rotenone induction of H2O2 inhibits mTOR-mediated S6K1 and 4E-BP1/eIF4E pathways, resulting in caspase-dependent and -independent apoptosis in neuronal cells. Our findings suggest that rotenone-induced neuronal loss in PD may be prevented by activating mTOR signaling and/or administering antioxidants. PMID:25304210

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

Activating transcription factor 4 underlies the pathogenesis of arsenic trioxide-mediated impairment of macrophage innate immune functions

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

Srivastava, Ritesh K.; Li, Changzhao

Chronic arsenic exposure to humans is considered immunosuppressive with augmented susceptibility to several infectious diseases. The exact molecular mechanisms, however, remain unknown. Earlier, we showed the involvement of unfolded protein response (UPR) signaling in arsenic-mediated impairment of macrophage functions. Here, we show that activating transcription factor 4 (ATF4), a UPR transcription factor, regulates arsenic trioxide (ATO)-mediated dysregulation of macrophage functions. In ATO-treated ATF4{sup +/+} wild-type mice, a significant down-regulation of CD11b expression was associated with the reduced phagocytic functions of peritoneal and lung macrophages. This severe immuno-toxicity phenotype was not observed in ATO-treated ATF4{sup +/−} heterozygous mice. To confirm thesemore » observations, we demonstrated in Raw 264.7 cells that ATF4 knock-down rescues ATO-mediated impairment of macrophage functions including cytokine production, bacterial engulfment and clearance of engulfed bacteria. Sustained activation of ATF4 by ATO in macrophages induces apoptosis, while diminution of ATF4 expression protects against ATO-induced apoptotic cell death. Raw 264.7 cells treated with ATO also manifest dysregulated Ca{sup ++} homeostasis. ATO induces Ca{sup ++}-dependent calpain-1 and caspase-12 expression which together regulated macrophage apoptosis. Additionally, apoptosis was also induced by mitochondria-regulated pathway. Restoring ATO-impaired Ca{sup ++} homeostasis in ER/mitochondria by treatments with the inhibitors of inositol 1,4,5-trisphosphate receptor (IP3R) and voltage-dependent anion channel (VDAC) attenuate innate immune functions of macrophages. These studies identify a novel role for ATF4 in underlying pathogenesis of macrophage dysregulation and immuno-toxicity of arsenic. - Highlights: • ATF4 regulates arsenic-mediated impairment in macrophage functions. • Arsenic-mediated alterations in pulmonary macrophage are diminished in ATF4{sup +/�

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

The Effect of Individual Factors on Health Behaviors Among College Students: The Mediating Effects of eHealth Literacy

PubMed Central

Chiang, ChiaHsun

2014-01-01

Background College students’ health behavior is a topic that deserves attention. Individual factors and eHealth literacy may affect an individual’s health behaviors. The integrative model of eHealth use (IMeHU) provides a parsimonious account of the connections among the digital divide, health care disparities, and the unequal distribution and use of communication technologies. However, few studies have explored the associations among individual factors, eHealth literacy, and health behaviors, and IMeHU has not been empirically investigated. Objective This study examines the associations among individual factors, eHealth literacy, and health behaviors using IMeHU. Methods The Health Behavior Scale is a 12-item instrument developed to measure college students’ eating, exercise, and sleep behaviors. The eHealth Literacy Scale is a 12-item instrument designed to measure college students’ functional, interactive, and critical eHealth literacy. A nationally representative sample of 525 valid college students in Taiwan was surveyed. A questionnaire was administered to collect background information about participants’ health status, degree of health concern, major, and the frequency with which they engaged in health-related discussions. This study used Amos 6.0 to conduct a confirmatory factor analysis to identify the best measurement models for the eHealth Literacy Scale and the Health Behavior Scale. We then conducted a multiple regression analysis to examine the associations among individual factors, eHealth literacy, and health behaviors. Additionally, causal steps approach was used to explore indirect (mediating) effects and Sobel tests were used to test the significance of the mediating effects. Results The study found that perceptions of better health status (t520=2.14-6.12, P<.001-.03) and greater concern for health (t520=2.58-6.95, P<.001-.003) influenced college students’ development of 3 dimensions of eHealth literacy and adoption of healthy eating

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.

A minireview of E4BP4/NFIL3 in heart failure.

PubMed

Velmurugan, Bharath Kumar; Chang, Ruey-Lin; Marthandam Asokan, Shibu; Chang, Chih-Fen; Day, Cecilia-Hsuan; Lin, Yueh-Min; Lin, Yuan-Chuan; Kuo, Wei-Wen; Huang, Chih-Yang

2018-06-01

Heart failure (HF) remains a major cause of morbidity and mortality worldwide. The primary cause identified for HF is impaired left ventricular myocardial function, and clinical manifestations may lead to severe conditions like pulmonary congestion, splanchnic congestion, and peripheral edema. Development of new therapeutic strategies remains the need of the hour for controlling the problem of HF worldwide. Deeper insights into the molecular mechanisms involved in etiopathology of HF indicate the significant role of calcium signaling, autocrine signaling pathways, and insulin-like growth factor-1 signaling that regulates the physiologic functions of heart growth and development such as contraction, metabolism, hypertrophy, cytokine signaling, and apoptosis. In view of these facts, a transcription factor (TF) regulating the myriad of these signaling pathways may prove as a lead candidate for development of therapeutics. Adenovirus E4 promoter-binding protein (E4BP4), also known as nuclear-factor, interleukin 3 regulated (NFIL3), a type of basic leucine zipper TF, is known to regulate the signaling processes involved in the functioning of heart. The current review discusses about the expression, structure, and functional role of E4BP4 in signaling processes with emphasis on calcium signaling mechanisms, autocrine signaling, and insulin-like growth factor II receptor-mediated processes regulated by E4BP4 that may regulate the pathogenesis of HF. We propose that E4BP4, being the critical component for the regulation of the above signaling processes, may serve as a novel therapeutic target for HF, and scientific investigations are merited in this direction. © 2018 Wiley Periodicals, Inc.

Amyloid mediates the association of apolipoprotein E e4 allele to cognitive function in older people

PubMed Central

Bennett, D; Schneider, J; Wilson, R; Bienias, J; Berry-Kravis, E; Arnold, S

2005-01-01

Background: The neurobiological changes underlying the association of the apolipoprotein E (APOE) e4 allele with level of cognition are poorly understood. Objective: To test the hypothesis that amyloid load can account for (mediate) the association of the APOE e4 allele with level of cognition assessed proximate to death. Methods: There were 44 subjects with clinically diagnosed Alzheimer's disease and 50 without dementia, who had participated in the Religious Orders Study. They underwent determination of APOE allele status, had comprehensive cognitive testing in the last year of life, and brain autopsy at death. The percentage area of cortex occupied by amyloid beta and the density of tau positive neurofibrillary tangles were quantified from six brain regions and averaged to yield summary measures of amyloid load and neurofibrillary tangles. Multiple regression analyses were used to examine whether amyloid load could account for the effect of allele status on level of cognition, controlling for age, sex, and education. Results: Possession of at least one APOE e4 allele was associated with lower level of cognitive function proximate to death (p = 0.04). The effect of the e4 allele was reduced by nearly 60% and was no longer significant after controlling for the effect of amyloid load, whereas there was a robust inverse association between amyloid and cognition (p = 0.001). Because prior work had suggested that neurofibrillary tangles could account for the association of amyloid on cognition, we next examined whether amyloid could account for the effect of allele status on tangles. In a series of regression analyses, e4 was associated with density of tangles (p = 0.002), but the effect of the e4 allele was reduced by more than 50% and was no longer significant after controlling for the effect of amyloid load. Conclusion: These findings are consistent with a sequence of events whereby the e4 allele works through amyloid deposition and subsequent tangle formation to

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

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

Anti-allergic activity of 2,4,6-trihydroxy-3-geranylacetophenone (tHGA) via attenuation of IgE-mediated mast cell activation and inhibition of passive systemic anaphylaxis

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

Tan, Ji Wei; Israf, Daud Ahmad; Harith, Hanis Haze

tHGA, a geranyl acetophenone compound originally isolated from a local shrub called Melicope ptelefolia, has been previously reported to prevent ovalbumin-induced allergic airway inflammation in a murine model of allergic asthma by targeting cysteinyl leukotriene synthesis. Mast cells are immune effector cells involved in the pathogenesis of allergic diseases including asthma by releasing cysteinyl leukotrienes. The anti-asthmatic properties of tHGA could be attributed to its inhibitory effect on mast cell degranulation. As mast cell degranulation is an important event in allergic responses, this study aimed to investigate the anti-allergic effects of tHGA in cellular and animal models of IgE-mediated mastmore » cell degranulation. For in vitro model of IgE-mediated mast cell degranulation, DNP-IgE-sensitized RBL-2H3 cells were pre-treated with tHGA before challenged with DNP-BSA to induce degranulation. For IgE-mediated passive systemic anaphylaxis, Sprague Dawley rats were sensitized by intraperitoneal injection of DNP-IgE before challenged with DNP-BSA. Both in vitro and in vivo models showed that tHGA significantly inhibited the release of preformed mediators (β-hexosaminidase and histamine) as well as de novo mediators (interleukin-4, tumour necrosis factor-α, prostaglandin D{sub 2} and leukotriene C{sub 4}). Pre-treatment of tHGA also prevented IgE-challenged RBL-2H3 cells and peritoneal mast cells from undergoing morphological changes associated with mast cell degranulation. These findings indicate that tHGA possesses potent anti-allergic activity via attenuation of IgE-mediated mast cell degranulation and inhibition of IgE-mediated passive systemic anaphylaxis. Thus, tHGA may have the potential to be developed as a mast cell stabilizer for the treatment of allergic diseases in the future. - Highlights: • The in vitro and in vivo mast cell stabilizing effects of tHGA were examined. • tHGA counteracts the plasma membrane deformation in degranulating

4E-BP is a target of the GCN2–ATF4 pathway during Drosophila development and aging

PubMed Central

Park, Jung-Eun; Zeng, Xiaomei

2017-01-01

Reduced amino acid availability attenuates mRNA translation in cells and helps to extend lifespan in model organisms. The amino acid deprivation–activated kinase GCN2 mediates this response in part by phosphorylating eIF2α. In addition, the cap-dependent translational inhibitor 4E-BP is transcriptionally induced to extend lifespan in Drosophila melanogaster, but through an unclear mechanism. Here, we show that GCN2 and its downstream transcription factor, ATF4, mediate 4E-BP induction, and GCN2 is required for lifespan extension in response to dietary restriction of amino acids. The 4E-BP intron contains ATF4-binding sites that not only respond to stress but also show inherent ATF4 activity during normal development. Analysis of the newly synthesized proteome through metabolic labeling combined with click chemistry shows that certain stress-responsive proteins are resistant to inhibition by 4E-BP, and gcn2 mutant flies have reduced levels of stress-responsive protein synthesis. These results indicate that GCN2 and ATF4 are important regulators of 4E-BP transcription during normal development and aging. PMID:27979906

Upregulation of the coagulation factor VII gene during glucose deprivation is mediated by activating transcription factor 4.

PubMed

Cronin, Katherine R; Mangan, Thomas P; Carew, Josephine A

2012-01-01

Constitutive production of blood coagulation proteins by hepatocytes is necessary for hemostasis. Stressful conditions trigger adaptive cellular responses and delay processing of most proteins, potentially affecting plasma levels of proteins secreted exclusively by hepatocytes. We examined the effect of glucose deprivation on expression of coagulation proteins by the human hepatoma cell line, HepG2. Expression of coagulation factor VII, which is required for initiation of blood coagulation, was elevated by glucose deprivation, while expression of other coagulation proteins decreased. Realtime PCR and ELISA demonstrated that the relative percentage expression +/- SD of steady-state F7 mRNA and secreted factor VII antigen were significantly increased (from 100+/-15% to 188+/-27% and 100+/-8.8% to 176.3+/-17.3% respectively, p<0.001) at 24 hr of treatment. The integrated stress response was induced, as indicated by upregulation of transcription factor ATF4 and of additional stress-responsive genes. Small interfering RNAs directed against ATF4 potently reduced basal F7 expression, and prevented F7 upregulation by glucose deprivation. The response of the endogenous F7 gene was replicated in reporter gene assays, which further indicated that ATF4 effects were mediated via interaction with an amino acid response element in the F7 promoter. Our data indicated that glucose deprivation enhanced F7 expression in a mechanism reliant on prior ATF4 upregulation primarily due to increased transcription from the ATF4 gene. Of five coagulation protein genes examined, only F7 was upregulated, suggesting that its functions may be important in a systemic response to glucose deprivation stress.

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

How is the effect of adolescent e-cigarette use on smoking onset mediated: A longitudinal analysis.

PubMed

Wills, Thomas A; Gibbons, Frederick X; Sargent, James D; Schweitzer, Rebecca J

2016-12-01

E-cigarette use by adolescents has been related to onset of cigarette smoking but there is little knowledge about the process(es) through which this occurs. Accordingly, we tested the role of cognitive and social factors for mediating the relation between e-cigarette use and smoking onset. A school-based survey was conducted with a baseline sample of 2,338 students in Hawaii (9th and 10th graders, mean age 14.7 years) who were surveyed in 2013 (Time 1, T1) and followed up 1 year later (Time 2, T2). We assessed e-cigarette use, cigarette smoking, demographic covariates, and 4 hypothesized mediators: smoking-related expectancies, prototypes, and peer affiliations as well as marijuana use. The primary structural modeling analysis, based on initial never-smokers, used an autoregressive model (entering T2 mediator values adjusted for T1 values) to test for mediational pathways in the relation between e-cigarette use at T1 and cigarette smoking status at T2. Results showed that e-cigarette use was related to all of the mediators. Tests of indirect effects indicated that changes in expectancies, affiliations, and marijuana use were significant pathways in the relation between e-cigarette use and smoking onset. A direct effect from e-cigarette use to smoking onset was nonsignificant. Findings were replicated across autoregressive and prospective models. We conclude that the relation between adolescent e-cigarette use and smoking onset is in part attributable to cognitive and social processes that follow from e-cigarette use. Further research is needed to understand the relative role of nicotine and psychosocial factors in smoking onset. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Host and Viral Factors in HIV-Mediated Bystander Apoptosis

PubMed Central

Garg, Himanshu; Joshi, Anjali

2017-01-01

Human immunodeficiency virus (HIV) infections lead to a progressive loss of CD4 T cells primarily via the process of apoptosis. With a limited number of infected cells and vastly disproportionate apoptosis in HIV infected patients, it is believed that apoptosis of uninfected bystander cells plays a significant role in this process. Disease progression in HIV infected individuals is highly variable suggesting that both host and viral factors may influence HIV mediated apoptosis. Amongst the viral factors, the role of Envelope (Env) glycoprotein in bystander apoptosis is well documented. Recent evidence on the variability in apoptosis induction by primary patient derived Envs underscores the role of Env glycoprotein in HIV disease. Amongst the host factors, the role of C-C Chemokine Receptor type 5 (CCR5), a coreceptor for HIV Env, is also becoming increasingly evident. Polymorphisms in the CCR5 gene and promoter affect CCR5 cell surface expression and correlate with both apoptosis and CD4 loss. Finally, chronic immune activation in HIV infections induces multiple defects in the immune system and has recently been shown to accelerate HIV Env mediated CD4 apoptosis. Consequently, those factors that affect CCR5 expression and/or immune activation in turn indirectly regulate HIV mediated apoptosis making this phenomenon both complex and multifactorial. This review explores the complex role of various host and viral factors in determining HIV mediated bystander apoptosis. PMID:28829402

Upregulation of the Coagulation Factor VII Gene during Glucose Deprivation Is Mediated by Activating Transcription Factor 4

PubMed Central

Cronin, Katherine R.; Mangan, Thomas P.; Carew, Josephine A.

2012-01-01

Background Constitutive production of blood coagulation proteins by hepatocytes is necessary for hemostasis. Stressful conditions trigger adaptive cellular responses and delay processing of most proteins, potentially affecting plasma levels of proteins secreted exclusively by hepatocytes. We examined the effect of glucose deprivation on expression of coagulation proteins by the human hepatoma cell line, HepG2. Methodology/Principal Findings Expression of coagulation factor VII, which is required for initiation of blood coagulation, was elevated by glucose deprivation, while expression of other coagulation proteins decreased. Realtime PCR and ELISA demonstrated that the relative percentage expression +/− SD of steady-state F7 mRNA and secreted factor VII antigen were significantly increased (from 100+/−15% to 188+/−27% and 100+/−8.8% to 176.3+/−17.3% respectively, p<0.001) at 24 hr of treatment. The integrated stress response was induced, as indicated by upregulation of transcription factor ATF4 and of additional stress-responsive genes. Small interfering RNAs directed against ATF4 potently reduced basal F7 expression, and prevented F7 upregulation by glucose deprivation. The response of the endogenous F7 gene was replicated in reporter gene assays, which further indicated that ATF4 effects were mediated via interaction with an amino acid response element in the F7 promoter. Conclusions/Significance Our data indicated that glucose deprivation enhanced F7 expression in a mechanism reliant on prior ATF4 upregulation primarily due to increased transcription from the ATF4 gene. Of five coagulation protein genes examined, only F7 was upregulated, suggesting that its functions may be important in a systemic response to glucose deprivation stress. PMID:22848420

The prevalence of eosinophilic esophagitis in pediatric patients with IgE-mediated food allergy

PubMed Central

Hill, David A.; Dudley, Jesse W.; Spergel, Jonathan M.

2017-01-01

BACKGROUND Eosinophilic esophagitis (EoE) is an allergic inflammatory disease that is triggered by food allergens and characterized by progressive esophageal dysfunction. Recently, EoE has been identified in patients undergoing oral immunotherapy (OIT) for IgE-mediated food allergy, suggesting an association. OBJECTIVE We sought to ascertain whether significant associations exist between IgE-mediated food allergies and EoE. METHODS Utilizing analysis of EMR data and manual chart review, we examined our sub-specialty care network of 35,528 children and adolescents to identify and characterize patients with IgE-mediated, and EoE food allergy. The most common food allergens were defined, and the prevalence of EoE in patients with IgE-mediated food allergy was determined. Logistic regression was used to measure the extent to which IgE-mediated food allergy to specific foods is associated with EoE. RESULTS The most common causes of EoE were milk, grains, meats, peanut, tree nuts, egg, and soy, an allergen pattern that is distinct from that of IgE-mediated food allergy. The prevalence of EoE in patients with IgE-mediated food allergy was higher than that reported in the general population (4.7% vs 0.04%). The distribution of IgE-mediated food allergens in patients with EoE was similar to that of the general population, and IgE-mediated allergy to egg (2.27; 1.91–2.64), milk (4.19; 3.52–4.97), or shellfish (1.55; 1.24–1.92) was significantly associated with EoE diagnosis. CONCLUSIONS Our findings support a clinical association between these conditions that has implications for the management of children with food allergy, and particular relevance to patients undergoing OIT. PMID:28042003

The Prevalence of Eosinophilic Esophagitis in Pediatric Patients with IgE-Mediated Food Allergy.

PubMed

Hill, David A; Dudley, Jesse W; Spergel, Jonathan M

Eosinophilic esophagitis (EoE) is an allergic inflammatory disease that is triggered by food allergens and characterized by progressive esophageal dysfunction. Recently, EoE has been identified in patients who underwent oral immunotherapy (OIT) for IgE-mediated food allergy, suggesting an association. We sought to ascertain whether significant associations exist between IgE-mediated food allergies and EoE. Using the analysis of electronic medical record data and manual chart review, we examined our subspecialty care network of 35,528 children and adolescents to identify and characterize patients with IgE-mediated and EoE food allergy. The most common food allergens were defined, and the prevalence of EoE in patients with IgE-mediated food allergy was determined. Logistic regression was used to measure the extent to which IgE-mediated food allergy to specific foods is associated with EoE. The most common causes of EoE were milk, soy, egg, grains, and meats, an allergen pattern that is distinct from that of IgE-mediated food allergy. The prevalence of EoE in patients with IgE-mediated food allergy was higher than that reported in the general population (4.7% vs 0.04%). The distribution of IgE-mediated food allergens in patients with EoE was similar to that of the general population, and IgE-mediated allergy to egg (2.27; 1.91-2.64), milk (4.19; 3.52-4.97), or shellfish (1.55; 1.24-1.92) was significantly associated with an EoE diagnosis. Our findings support a clinical association between these conditions that has implications for the management of children with food allergy, and particular relevance to patients undergoing OIT. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

10 CFR 4.333 - Mediation.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Mediation. 4.333 Section 4.333 Energy NUCLEAR REGULATORY... Investigation, Conciliation, and Enforcement Procedures § 4.333 Mediation. (a) Referral of complaints for mediation. NRC will refer to a mediation agency designated by the Secretary of the Department of Health and...

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

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.

Epigenome-wide association study reveals longitudinally stable DNA methylation differences in CD4+ T cells from children with IgE-mediated food allergy.

PubMed

Martino, David; Joo, Jihoon E; Sexton-Oates, Alexandra; Dang, Thanh; Allen, Katrina; Saffery, Richard; Prescott, Susan

2014-07-01

Food allergy is mediated by a combination of genetic and environmental risk factors, potentially mediated by epigenetic mechanisms. CD4+ T-cells are key drivers of the allergic response, and may therefore harbor epigenetic variation in association with the disease phenotype. Here we retrospectively examined genome-wide DNA methylation profiles (~450,000 CpGs) from CD4+ T-cells on a birth cohort of 12 children with IgE-mediated food allergy diagnosed at 12-months, and 12 non-allergic controls. DNA samples were available at two time points, birth and 12-months. control comparisons of CD4+ methylation profiles identified 179 differentially methylated probes (DMP) at 12-months and 136 DMP at birth (FDR-adjusted P value<0.05, delta β>0.1). Approximately 30% of DMPs were coincident with previously annotated SNPs. A total of 92 [corrected] allergy-associated non-SNP DMPs were present at birth when individuals were initially disease-free, potentially implicating these loci in the causal pathway. Pathway analysis of differentially methylated genes identified several MAP kinase signaling molecules. Mass spectrometry was used to validate 15 CpG sites at 3 candidate genes. Combined analysis of differential methylation with gene expression profiles revealed gene expression differences at some but not all allergy associated differentially methylated genes. Thus, dysregulation of DNA methylation at MAPK signaling-associated genes during early CD4+ T-cell development may contribute to suboptimal T-lymphocyte responses in early childhood associated with the development of food allergy.

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

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

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.

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.

STAT6: its role in interleukin 4-mediated biological functions.

PubMed

Takeda, K; Kishimoto, T; Akira, S

1997-05-01

Interleukin (IL) 4 is known to be a cytokine which plays a central role in the regulation of immune response. Studies on cytokine signal transduction have clarified the mechanism by which IL4 exerts its functions. Two cytoplasmic proteins, signal transducer and activator of transcription (STAT) 6 and IL4-induced phosphotyrosine substrate/insulin receptor substrate 2 (4PS/IRS2), are activated in IL4 signal transduction. Recent studies from STAT6-deficient mice have revealed the essential role of STAT6 in IL4-mediated biological actions. In addition, STAT6 has also been demonstrated to be important for the functions mediated by IL13, which is related to IL4. IL4 and IL13 have been shown to induce the production of IgE, which is a major mediator in an allergic response. These findings indicate that STAT6 activation is involved in IL4- and IL13-mediated disorders such as allergy.

E1B and E4 oncoproteins of adenovirus antagonize the effect of apoptosis inducing factor

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

Turner, Roberta L.; Wilkinson, John C., E-mail: john.wilkinson@ndsu.edu; Ornelles, David A., E-mail: ornelles@wakehealth.edu

2014-05-15

Adenovirus inundates the productively infected cell with linear, double-stranded DNA and an abundance of single-stranded DNA. The cellular response to this stimulus is antagonized by the adenoviral E1B and E4 early genes. A mutant group C adenovirus that fails to express the E1B-55K and E4ORF3 genes is unable to suppress the DNA-damage response. Cells infected with this double-mutant virus display significant morphological heterogeneity at late times of infection and frequently contain fragmented nuclei. Nuclear fragmentation was due to the translocation of apoptosis inducing factor (AIF) from the mitochondria into the nucleus. The release of AIF was dependent on active poly(ADP-ribose)more » polymerase-1 (PARP-1), which appeared to be activated by viral DNA replication. Nuclear fragmentation did not occur in AIF-deficient cells or in cells treated with a PARP-1 inhibitor. The E1B-55K or E4ORF3 proteins independently prevented nuclear fragmentation subsequent to PARP-1 activation, possibly by altering the intracellular distribution of PAR-modified proteins. - Highlights: • E1B-55K or E4orf3 prevents nuclear fragmentation. • Nuclear fragmentation requires AIF and PARP-1 activity. • Adenovirus DNA replication activates PARP-1. • E1B-55K or E4orf3 proteins alter the distribution of PAR.« less

Immunoglobulin E-Mediated Autoimmunity

PubMed Central

Maurer, Marcus; Altrichter, Sabine; Schmetzer, Oliver; Scheffel, Jörg; Church, Martin K.; Metz, Martin

2018-01-01

The study of autoimmunity mediated by immunoglobulin E (IgE) autoantibodies, which may be termed autoallergy, is in its infancy. It is now recognized that systemic lupus erythematosus, bullous pemphigoid (BP), and chronic urticaria, both spontaneous and inducible, are most likely to be mediated, at least in part, by IgE autoantibodies. The situation in other conditions, such as autoimmune uveitis, rheumatoid arthritis, hyperthyroid Graves’ disease, autoimmune pancreatitis, and even asthma, is far less clear but evidence for autoallergy is accumulating. To be certain of an autoallergic mechanism, it is necessary to identify both IgE autoantibodies and their targets as has been done with the transmembrane protein BP180 and the intracellular protein BP230 in BP and IL-24 in chronic spontaneous urticaria. Also, IgE-targeted therapies, such as anti-IgE, must have been shown to be of benefit to patients as has been done with both of these conditions. This comprehensive review of the literature on IgE-mediated autoallergy focuses on three related questions. What do we know about the prevalence of IgE autoantibodies and their targets in different diseases? What do we know about the relevance of IgE autoantibodies in different diseases? What do we know about the cellular and molecular effects of IgE autoantibodies? In addition to providing answers to these questions, based on a broad review of the literature, we outline the current gaps of knowledge in our understanding of IgE autoantibodies and describe approaches to address them. PMID:29686678

The E3 ubiquitin ligase NEDD4 mediates cell migration signaling of EGFR in lung cancer cells.

PubMed

Shao, Genbao; Wang, Ranran; Sun, Aiqin; Wei, Jing; Peng, Ke; Dai, Qian; Yang, Wannian; Lin, Qiong

2018-02-19

EGFR-dependent cell migration plays an important role in lung cancer progression. Our previous study observed that the HECT E3 ubiquitin ligase NEDD4 is significantly correlated with tumor metastasis and required for migration and invasion signaling of EGFR in gastric cancer cells. However, how NEDD4 promotes the EGFR-dependent lung cancer cell migration is unknown. This study is to elucidate the mechanism by which NEDD4 mediates the EGFR lung cancer migration signaling. Lentiviral vector-loaded NEDD4 shRNA was used to deplete endogenous NEDD4 in lung cancer cell lines. Effects of the NEDD4 knockdown on the EGFR-dependent or independent lung cancer cell migration were determined using the wound-healing and transwell assays. Association of NEDD4 with activated EGFR was assayed by co-immunoprecipitation. Co-expression of NEDD4 with EGFR or PTEN was determined by immunohistochemical (IHC) staining in 63 lung adenocarcinoma tissue samples. Effects of NEDD4 ectopic expression or knockdown on PTEN ubiquitination and down-regulation, AKT activation and lysosomal secretion were examined using the GST-Uba pulldown assay, immunoblotting, immunofluorescent staining and a human cathepsin B ELISA assay respectively. The specific cathepsin B inhibitor CA-074Me was used for assessing the role of cathepsin B in lung cancer cell migration. Knockdown of NEDD4 significantly reduced EGF-stimulated cell migration in non-small cell lung carcinoma (NSCLC) cells. Co-immunoprecipitation assay found that NEDD4 is associated with EGFR complex upon EGF stimulation, and IHC staining indicates that NEDD4 is co-expressed with EGFR in lung adenocarcinoma tumor tissues, suggesting that NEDD4 might mediate lung cancer cell migration by interaction with the EGFR signaling complex. Interestingly, NEDD4 promotes the EGF-induced cathepsin B secretion, possibly through lysosomal exocytosis, as overexpression of the ligase-dead mutant of NEDD4 impedes lysosomal secretion, and knockdown of NEDD4

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.

eIF4E and eIF4GI have distinct and differential imprints on multiple myeloma's proteome and signaling

PubMed Central

Attar-Schneider, Oshrat; Pasmanik-Chor, Metsada; Tartakover-Matalon, Shelly

2015-01-01

Accumulating data indicate translation plays a role in cancer biology, particularly its rate limiting stage of initiation. Despite this evolving recognition, the function and importance of specific translation initiation factors is unresolved. The eukaryotic translation initiation complex eIF4F consists of eIF4E and eIF4G at a 1:1 ratio. Although it is expected that they display interdependent functions, several publications suggest independent mechanisms. This study is the first to directly assess the relative contribution of eIF4F components to the expressed cellular proteome, transcription factors, microRNAs, and phenotype in a malignancy known for extensive protein synthesis-multiple myeloma (MM). Previously, we have shown that eIF4E/eIF4GI attenuation (siRNA/Avastin) deleteriously affected MM cells' fate and reduced levels of eIF4E/eIF4GI established targets. Here, we demonstrated that eIF4E/eIF4GI indeed have individual influences on cell proteome. We used an objective, high throughput assay of mRNA microarrays to examine the significance of eIF4E/eIF4GI silencing to several cellular facets such as transcription factors, microRNAs and phenotype. We showed different imprints for eIF4E and eIF4GI in all assayed aspects. These results promote our understanding of the relative contribution and importance of eIF4E and eIF4GI to the malignant phenotype and shed light on their function in eIF4F translation initiation complex. PMID:25717031

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

Fibroblast growth factor receptor 4 (FGFR4) and fibroblast growth factor 19 (FGF19) autocrine enhance breast cancer cells survival.

PubMed

Tiong, Kai Hung; Tan, Boon Shing; Choo, Heng Lungh; Chung, Felicia Fei-Lei; Hii, Ling-Wei; Tan, Si Hoey; Khor, Nelson Tze Woei; Wong, Shew Fung; See, Sze-Jia; Tan, Yuen-Fen; Rosli, Rozita; Cheong, Soon-Keng; Leong, Chee-Onn

2016-09-06

Basal-like breast cancer is an aggressive tumor subtype with poor prognosis. The discovery of underlying mechanisms mediating tumor cell survival, and the development of novel agents to target these pathways, is a priority for patients with basal-like breast cancer. From a functional screen to identify key drivers of basal-like breast cancer cell growth, we identified fibroblast growth factor receptor 4 (FGFR4) as a potential mediator of cell survival. We found that FGFR4 mediates cancer cell survival predominantly via activation of PI3K/AKT. Importantly, a subset of basal-like breast cancer cells also secrete fibroblast growth factor 19 (FGF19), a canonical ligand specific for FGFR4. siRNA-mediated silencing of FGF19 or neutralization of extracellular FGF19 by anti-FGF19 antibody (1A6) decreases AKT phosphorylation, suppresses cancer cell growth and enhances doxorubicin sensitivity only in the FGFR4+/FGF19+ breast cancer cells. Consistently, FGFR4/FGF19 co-expression was also observed in 82 out of 287 (28.6%) primary breast tumors, and their expression is strongly associated with AKT phosphorylation, Ki-67 staining, higher tumor stage and basal-like phenotype. In summary, our results demonstrated the presence of an FGFR4/FGF19 autocrine signaling that mediates the survival of a subset of basal-like breast cancer cells and suggest that inactivation of this autocrine loop may potentially serve as a novel therapeutic intervention for future treatment of breast cancers.

Novel functions for the transcription factor E2F4 in development and disease

PubMed Central

Sage, Julien

2016-01-01

ABSTRACT The E2F family of transcription factors is a key determinant of cell proliferation in response to extra- and intra-cellular signals. Within this family, E2F4 is a transcriptional repressor whose activity is critical to engage and maintain cell cycle arrest in G0/G1 in conjunction with members of the retinoblastoma (RB) family. However, recent observations challenge this paradigm and indicate that E2F4 has a multitude of functions in cells besides this cell cycle regulatory role, including in embryonic and adult stem cells, during regenerative processes, and in cancer. Some of these new functions are independent of the RB family and involve direct activation of target genes. Here we review the canonical functions of E2F4 and discuss recent evidence expanding the role of this transcription factor, with a focus on cell fate decisions in tissue homeostasis and regeneration. PMID:27753528

Expression of the Eukaryotic Translation Initiation Factors 4E and 2α in Non-Hodgkin’s Lymphomas

PubMed Central

Wang, Songtao; Rosenwald, Igor B.; Hutzler, Michael J.; Pihan, German A.; Savas, Lou; Chen, Jane-Jane; Woda, Bruce A.

1999-01-01

Transition of cells from quiescence to proliferation requires an increase in the rate of protein synthesis, which is regulated in part by two key translation initiation factors, 4E and 2α. The expression and activity of both factors are increased transiently when normal resting cells are stimulated to proliferate. They are constitutively elevated in oncogene transformed cultured cells, and overexpression of either initiation factor in rodent cells makes them tumorigenic. In this study we investigate an association between the expression of translation initiation factors and lymphomagenesis. We have analyzed the expression of the protein synthesis initiation factors 4E and 2α by immunohistochemistry in reactive lymph nodes and several types of non-Hodgkin’s lymphoma representing a wide range of clinical behaviors based on the Revised European-American Lymphoma behavioral classification. The study included 7 benign lymph nodes with follicular hyperplasia, 26 indolent lymphomas (6 marginal zone lymphomas, 7 small lymphocytic lymphomas, and 13 follicular lymphomas, grades 1 and 2), 16 moderately aggressive lymphomas (8 mantle cell lymphomas and 8 follicular lymphomas, grade 3), 24 aggressive lymphomas (14 large-B-cell lymphomas and 10 anaplastic large-cell lymphomas), and 15 highly aggressive lymphomas (7 lymphoblastic lymphomas and 8 Burkitt’s lymphomas). Strong expression of initiation factors 4E and 2α was demonstrated in the germinal centers of reactive follicles. Minimal or no expression was seen in the mantle zones and surrounding paracortices, indicating that high expression of initiation factors 4E and 2α is associated with the active proliferation of lymphocytes. Most cases of aggressive and highly aggressive lymphomas showed strong expression of initiation factors 4E and 2α, in contrast to the cases of indolent and moderately aggressive lymphoma, in which their expression was intermediate between the germinal centers and the mantles of reactive

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.

Measurement of filling factor 5/2 quasiparticle interference with observation of charge e/4 and e/2 period oscillations.

PubMed

Willett, R L; Pfeiffer, L N; West, K W

2009-06-02

A standing problem in low-dimensional electron systems is the nature of the 5/2 fractional quantum Hall (FQH) state: Its elementary excitations are a focus for both elucidating the state's properties and as candidates in methods to perform topological quantum computation. Interferometric devices may be used to manipulate and measure quantum Hall edge excitations. Here we use a small-area edge state interferometer designed to observe quasiparticle interference effects. Oscillations consistent in detail with the Aharonov-Bohm effect are observed for integer quantum Hall and FQH states (filling factors nu = 2, 5/3, and 7/3) with periods corresponding to their respective charges and magnetic field positions. With these factors as charge calibrations, periodic transmission through the device consistent with quasiparticle charge e/4 is observed at nu = 5/2 and at lowest temperatures. The principal finding of this work is that, in addition to these e/4 oscillations, periodic structures corresponding to e/2 are also observed at 5/2 nu and at lowest temperatures. Properties of the e/4 and e/2 oscillations are examined with the device sensitivity sufficient to observe temperature evolution of the 5/2 quasiparticle interference. In the model of quasiparticle interference, this presence of an effective e/2 period may empirically reflect an e/2 quasiparticle charge or may reflect multiple passes of the e/4 quasiparticle around the interferometer. These results are discussed within a picture of e/4 quasiparticle excitations potentially possessing non-Abelian statistics. These studies demonstrate the capacity to perform interferometry on 5/2 excitations and reveal properties important for understanding this state and its excitations.

Measurement of filling factor 5/2 quasiparticle interference with observation of charge e/4 and e/2 period oscillations

PubMed Central

Willett, R. L.; Pfeiffer, L. N.; West, K. W.

2009-01-01

A standing problem in low-dimensional electron systems is the nature of the 5/2 fractional quantum Hall (FQH) state: Its elementary excitations are a focus for both elucidating the state's properties and as candidates in methods to perform topological quantum computation. Interferometric devices may be used to manipulate and measure quantum Hall edge excitations. Here we use a small-area edge state interferometer designed to observe quasiparticle interference effects. Oscillations consistent in detail with the Aharonov–Bohm effect are observed for integer quantum Hall and FQH states (filling factors ν = 2, 5/3, and 7/3) with periods corresponding to their respective charges and magnetic field positions. With these factors as charge calibrations, periodic transmission through the device consistent with quasiparticle charge e/4 is observed at ν = 5/2 and at lowest temperatures. The principal finding of this work is that, in addition to these e/4 oscillations, periodic structures corresponding to e/2 are also observed at 5/2 ν and at lowest temperatures. Properties of the e/4 and e/2 oscillations are examined with the device sensitivity sufficient to observe temperature evolution of the 5/2 quasiparticle interference. In the model of quasiparticle interference, this presence of an effective e/2 period may empirically reflect an e/2 quasiparticle charge or may reflect multiple passes of the e/4 quasiparticle around the interferometer. These results are discussed within a picture of e/4 quasiparticle excitations potentially possessing non-Abelian statistics. These studies demonstrate the capacity to perform interferometry on 5/2 excitations and reveal properties important for understanding this state and its excitations. PMID:19433804

The effects of imidacloprid combined with endosulfan on IgE-mediated mouse bone marrow-derived mast cell degranulation and anaphylaxis.

PubMed

Shi, Lin-Bo; Xu, Hua-Ping; Wu, Yu-Jie; Li, Xin; Gao, Jin-Yan; Chen, Hong-Bing

2018-06-01

Low levels of endosulfan are known to stimulate mast cells to release allergic mediators, while imidacloprid can inhibit IgE-mediated mast cell degranulation. However, little information about the effects of both pesticides together on mast cell degranulation is available. To measure the effects, IgE-activated mouse bone marrow-derived mast cells (BMMCs) were treated with imidacloprid and endosulfan, individually, and simultaneously at equi-molar concentrations in tenfold steps ranging from 10 -4 to 10 -11  M, followed by measuring several allergy-related parameters expressed in BMMCs: the mediator production and influx of Ca 2+ , the phosphorylation content of NF-κB in the FcεRI signaling pathway. Then, the effects of the mixtures on IgE-induced passive systemic anaphylaxis (PSA) of BALB/c was detectded. This study clearly showed that the application of equi-molar mixtures of both pesticides with 10 -4 -10 -5  M significantly inhibited the IgE-mediated mouse bone marrow-derived mast cells degranulation in vitro and 10 -4  M of them decreased IgE-mediated PSA in vivo, as the application of imidacloprid at the same concentration alone did. Morever endosulfan alone had no remarkable stimulatory effects on any of the factors measured. In conclusion, simultaneous application of equi-molar concentrations of both pesticides generally showed highly similar responses compared to the responses to imidacloprid alone, suggesting that the effects of the mixture could be solely attributed to the effects of imidacloprid. Copyright © 2018 Elsevier Inc. All rights reserved.

Hazardous drinking and military community functioning: identifying mediating risk factors.

PubMed

Foran, Heather M; Heyman, Richard E; Slep, Amy M Smith

2011-08-01

Hazardous drinking is a serious societal concern in military populations. Efforts to reduce hazardous drinking among military personnel have been limited in effectiveness. There is a need for a deeper understanding of how community-based prevention models apply to hazardous drinking in the military. Community-wide prevention efforts may be most effective in targeting community functioning (e.g., support from formal agencies, community cohesion) that impacts hazardous drinking via other proximal risk factors. The goal of the current study is to inform community-wide prevention efforts by testing a model of community functioning and mediating risk factors of hazardous drinking among active duty U.S. Air Force personnel. A large, representative survey sample of U.S. Air Force active duty members (N = 52,780) was collected at 82 bases worldwide. Hazardous drinking was assessed with the widely used Alcohol Use Disorders Identification Test (Saunders, Aasland, Babor, de la Fuente, & Grant, 1993). A variety of individual, family, and community measures were also assessed. Structural equation modeling was used to test a hypothesized model of community functioning, mediating risk factors and hazardous drinking. Depressive symptoms, perceived financial stress, and satisfaction with the U.S. Air Force were identified as significant mediators of the link between community functioning and hazardous drinking for men and women. Relationship satisfaction was also identified as a mediator for men. These results provide a framework for further community prevention research and suggest that prevention efforts geared at increasing aspects of community functioning (e.g., the U.S. Air Force Community Capacity model) may indirectly lead to reductions in hazardous drinking through other proximal risk factors.

Krüppel-like factor 4 is induced by rapamycin and mediates the anti-proliferative effect of rapamycin in rat carotid arteries after balloon injury.

PubMed

Wang, Ying; Zhao, Beilei; Zhang, Yi; Tang, Zhihui; Shen, Qiang; Zhang, Youyi; Zhang, Weizhen; Du, Jie; Chien, Shu; Wang, Nanping

2012-04-01

The transcription factor, Krüppel-like factor 4 (KLF4), plays an important role in regulating the proliferation of vascular smooth muscle cells. This study aimed to examine the effect of rapamycin on the expression of KLF4 and the role of KLF4 in arterial neointimal formation. Expression of KLF4 was monitored using real-time PCR and immunoblotting in cultured vascular smooth muscle cells. and in rat carotid arteries in vivo after balloon injury. Adenovirus-mediated overexpression and siRNA-mediated knockdown of KLF4 were used to examine the role of KLF4 in mediating the anti-proliferative role of rapamycin . KLF4-regulated genes were identified using cDNA microarray. Rapamycin induced the expression of KLF4 in vitro and in vivo. Overexpression of KLF4 inhibited cell proliferation and the activity of mammalian target of rapamycin (mTOR) and its downstream pathways, including 4EBP-1 and p70S6K in vascular smooth muscle cells and prevented the neointimal formation in the balloon-injured arteries. KLF4 up-regulated the expression of GADD45β, p57(kip2) and p27(kip1) . Furthermore, knockdown of KLF4 attenuated the anti-proliferative effect of rapamycin both in vitro and in vivo. KLF4 plays an important role in mediating the anti-proliferative effect of rapamycin in VSMCs and balloon-injured arteries. Thus, it is a potential target for the treatment of proliferative vascular disorders such as restenosis after angioplasty. © 2011 The Authors. British Journal of Pharmacology © 2011 The British Pharmacological Society.

E-type prostanoid receptor 4 (EP4) in disease and therapy

PubMed Central

Konya, Viktoria; Marsche, Gunther; Schuligoi, Rufina; Heinemann, Akos

2013-01-01

The large variety of biological functions governed by prostaglandin (PG) E2 is mediated by signaling through four distinct E-type prostanoid (EP) receptors. The availability of mouse strains with genetic ablation of each EP receptor subtype and the development of selective EP agonists and antagonists have tremendously advanced our understanding of PGE2 as a physiologically and clinically relevant mediator. Moreover, studies using disease models revealed numerous conditions in which distinct EP receptors might be exploited therapeutically. In this context, the EP4 receptor is currently emerging as most versatile and promising among PGE2 receptors. Anti-inflammatory, anti-thrombotic and vasoprotective effects have been proposed for the EP4 receptor, along with its recently described unfavorable tumor-promoting and pro-angiogenic roles. A possible explanation for the diverse biological functions of EP4 might be the multiple signaling pathways switched on upon EP4 activation. The present review attempts to summarize the EP4 receptor-triggered signaling modules and the possible therapeutic applications of EP4-selective agonists and antagonists. PMID:23523686

Sox2 is translationally activated by eukaryotic initiation factor 4E in human glioma-initiating cells

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

Ge, Yuqing; Zhou, Fengbiao; Chen, Hong

2010-07-09

Sox2, a master transcription factor, contributes to the generation of induced pluripotent stem cells and plays significant roles in sustaining the self-renewal of neural stem cells and glioma-initiating cells. Understanding the functional differences of Sox2 between glioma-initiating cells and normal neural stem cells would contribute to therapeutic approach for treatment of brain tumors. Here, we first demonstrated that Sox2 could contribute to the self-renewal and proliferation of glioma-initiating cells. The following experiments showed that Sox2 was activated at translational level in a subset of human glioma-initiating cells compared with the normal neural stem cells. Further investigation revealed there was amore » positive correlation between Sox2 and eukaryotic initiation factor 4E (eIF4E) in glioma tissues. Down-regulation of eIF4E decreased Sox2 protein level without altering its mRNA level in glioma-initiating cells, indicating that Sox2 was activated by eIF4E at translational level. Furthermore, eIF4E was presumed to regulate the expression of Sox2 by its 5' untranslated region (5' UTR) sequence. Our results suggest that the eIF4E-Sox2 axis is a novel mechanism of unregulated self-renewal of glioma-initiating cells, providing a potential therapeutic target for glioma.« less

Trichostatin A-induced apoptosis is mediated by Kruppel-like factor 4 in ovarian and lung cancer.

PubMed

Zohre, Sadeghi; Kazem, Nejati-Koshki; Abolfazl, Akbarzadeh; Mohammad, Rahmati-Yamchi; Aliakbar, Movassaghpour; Effat, Alizadeh; Zahra, Davoudi; Hassan, Dariushnejad; Nosratollah, Zarghami

2014-01-01

The istone deacetylase (HDAC) inhibitor trichostatin A (TSA) is known to mediate the regulation of gene expression and anti proliferation activity in cancer cells. Kruppel-like factor 4 (klf4) is a zinc finger- containing transcription factor of the SP/KLF family, that is expressed in a variety of tissues and regulates cell proliferation, differentiation, tumorigenesis, and apoptosis. It may either either function as a tumor suppressor or an oncogene depending on genetic context of tumors. In this study, we tested the possibility that TSA may increase klf4 expression and cancer cell growth inhibition and apoptosis in SKOV-3 and A549 cells. The cytotoxicity of TSA was determined using the MTT assay test, while klf4 gene expression was assessed by real time PCR and to ability of TSA to induce apoptosis using a Vybrant Apoptosis Assay kit. Our results showed that TSA exerted dose and time dependent cytotoxicity effect on SKOV-3 and A549 cells. Moreover TSA up-regulated klf4 expression. Flow cytometric analysis demonstrated that apoptosis was increased after TSA treatment. Taken together, this study showed that TSA increased klf4 expression in SKOV3 and A549 cell lines, consequently, klf4 may played a tumor-suppressor role by increasing both cell growth inhibition and apoptosis. This study sheds light on the details of molecular mechanisms of HDACI-induced cell cycle arrest and apoptosis.

29 CFR 1403.4 - Assignment of mediators.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 4 2010-07-01 2010-07-01 false Assignment of mediators. 1403.4 Section 1403.4 Labor Regulations Relating to Labor (Continued) FEDERAL MEDIATION AND CONCILIATION SERVICE FUNCTIONS AND DUTIES § 1403.4 Assignment of mediators. The Federal Service will assign one or more mediators to each labor...

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

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

Regulation of Membrane-Type 4 Matrix Metalloproteinase by SLUG Contributes to Hypoxia-Mediated Metastasis12

PubMed Central

Huang, Chi-Hung; Yang, Wen-Hao; Chang, Shyue-Yih; Tai, Shyh-Kuan; Tzeng, Cheng-Hwei; Kao, Jung-Yie; Wu, Kou-Juey; Yang, Muh-Hwa

2009-01-01

The hypoxic tumor environment has been shown to be critical to cancer metastasis through the promotion of angiogenesis, induction of epithelial-mesenchymal transition (EMT), and acquisition of invasive potential. However, the impact of hypoxia on the expression profile of the proteolytic enzymes involved in invasiveness is relatively unknown. Membrane-type 4 matrix metalloproteinase (MT4-MMP) is a glycosyl-phosphatidyl inositol-anchored protease that has been shown to be overexpressed in human cancers. However, detailed mechanisms regarding the regulation and function of MT4-MMP expression in tumor cells remain unknown. Here, we demonstrate that hypoxia or overexpression of hypoxia-inducible factor-1α (HIF-1α) induced MT4-MMP expression in human cancer cells. Activation of SLUG, a transcriptional factor regulating the EMT process of human cancers, by HIF-1α was critical for the induction of MT4-MMP under hypoxia. SLUG regulated the transcription of MT4-MMP through direct binding to the E-box located in its proximal promoter. Short-interference RNA-mediated knockdown of MT4-MMP attenuated in vitro invasiveness and in vivo pulmonary colonization of tumor cells without affecting cell migratory ability. MT4-MMP promoted invasiveness and pulmonary colonization through modulation of the expression profile of MMPs and angiogenic factors. Finally, coexpression of HIF-1α and MT4-MMP in human head and neck cancer was predictive of a worse clinical outcome. These findings establish a novel signaling pathway for hypoxia-mediated metastasis and elucidate the underlying regulatory mechanism and functional significance of MT4-MMP in cancer metastasis. PMID:20019845

Platelet Factor 4 Mediates Inflammation in Cerebral Malaria

PubMed Central

Srivastava, Kalyan; Cockburn, Ian A.; Swaim, AnneMarie; Thompson, Laura E.; Tripathi, Abhai; Fletcher, Craig A.; Shirk, Erin M.; Sun, Henry; Kowalska, M. Anna; Fox-Talbot, Karen; Sullivan, David; Zavala, Fidel; Morrell, Craig N.

2008-01-01

Summary Cerebral malaria is a major complication of Plasmodium falciparum infection in children. The pathogenesis of cerebral malaria involves vascular inflammation, immune stimulation and obstruction of cerebral capillaries. Platelets have a prominent role in both immune responses and vascular obstruction. We now demonstrate that the platelet derived chemokine, platelet factor 4 (PF4)/CXCL4, promotes the development of experimental cerebral malaria. Plasmodium infected red blood cells (RBC) activated platelets independent of vascular effects, resulting in increased plasma PF4. PF4 or CXCR3 null mice had less ECM, decreased brain T-cell recruitment, and platelet depletion or aspirin treatment reduced the development of ECM. We conclude that Plasmodium infected RBC can activate platelets and platelet derived PF4 then contributes to immune activation and T-cell trafficking as part of the pathogenesis of ECM. PMID:18692777

Upregulation of calprotectin in mild IgE-mediated ovalbumin hypersensitivity

PubMed Central

Wang, Junli; Ma, Jingqiu; Sheng, Xiaoyang

2017-01-01

Calprotectin, also known as S100A8/A9, has been linked to gut inflammation caused by IgE-mediated food hypersensitivities, but the pathophysiologic abnormalities it causes remain to be determined. We created a mild food hypersensitivity model through oral gavage of ovalbumin in Norway brown rats without using immune adjuvant. Changes in the levels of calprotectin and inflammation-associated cytokines were then observed over time. We found that fecal calprotectin as well as jejunal and liver TLR4, TNF-α, NF-κB, IL-1β, and IL-6 were upregulated in hypersensitive rats. Additionally, the influence of calprotectin on CD4+ T and dendritic cells was observed by co-culturing CD4+ T cells with dendritic cells, which revealed a shift toward increased Th2 T cells in calprotectin-treated cultures. These results suggest that calprotectin, along with other inflammatory factors, promotes the inflammation seen in mild food allergy. PMID:28454097

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

3,4,5-Tricaffeoylquinic acid inhibits tumor necrosis factor-α-stimulated production of inflammatory mediators in keratinocytes via suppression of Akt- and NF-κB-pathways.

PubMed

Lee, Chung Soo; Lee, Seon Ae; Kim, Yun Jeong; Seo, Seong Jun; Lee, Min Won

2011-11-01

Keratinocytes may play an important role in the pathogenesis of skin disease in atopic dermatitis. Caffeoyl derivatives are demonstrated to have anti-inflammatory and anti-oxidant effects. However, the effect of 3,4,5-tricaffeoylquinic acid prepared from Aconium koreanum on the pro-inflammatory cytokine-stimulated keratinocyte responses remains uncertain. In human keratinocytes, we investigated the effect of 3,4,5-tricaffeoylquinic acid on the tumor necrosis factor (TNF)-α-stimulated production of inflammatory mediators in relation to the nuclear factor (NF)-κB and cell signaling Akt, which regulates the transcription genes involved in immune and inflammatory responses. 3,4,5-Tricaffeoylquinic acid inhibited the TNF-α-stimulated production of cytokines (IL-1β and IL-8) and chemokine (CCL17 and CCL27) in keratinocytes. Bay 11-7085 (an inhibitor of NF-κB activation) and Akt inhibitor attenuated the TNF-α-induced formation of inflammatory mediators. 3,4,5-Tricaffeoylquinic acid, Bay 11-7085, Akt inhibitor and N-acetylcysteine inhibited the TNF-α-induced activation of NF-κB, activation of Akt, and formation of reactive oxygen and nitrogen species. The results show that 3,4,5-tricaffeoylquinic acid seems to attenuate the TNF-α-stimulated inflammatory mediator production in keratinocytes by suppressing the activation of Akt and NF-κB pathways which may be mediated by reactive oxygen species. The findings suggest that 3,4,5-tricaffeoylquinic acid may exert an inhibitory effect against the pro-inflammatory mediator-induced skin disease. Copyright © 2011 Elsevier B.V. All rights reserved.

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.

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

Duplex unwinding and ATPase activities of the DEAD-box helicase eIF4A are coupled by eIF4G and eIF4B

PubMed Central

Özeş, Ali R.; Feoktistova, Kateryna; Avanzino, Brian C.; Fraser, Christopher S.

2011-01-01

Eukaryotic initiation factor 4A (eIF4A) is a DEAD-box helicase that stimulates translation initiation by unwinding mRNA secondary structure. The accessory proteins, eIF4G, eIF4B, and eIF4H enhance the duplex unwinding activity of eIF4A, but the extent to which they modulate eIF4A activity is poorly understood. Here, we use real time fluorescence assays to determine the kinetic parameters of duplex unwinding and ATP hydrolysis by these initiation factors. To ensure efficient duplex unwinding, eIF4B and eIF4G cooperatively activate the duplex unwinding activity of eIF4A. Our data reveal that eIF4H is much less efficient at stimulating eIF4A unwinding activity than eIF4B, implying that eIF4H is not able to completely substitute for eIF4B in duplex unwinding. By monitoring unwinding and ATPase assays using identical conditions, we demonstrate that eIF4B couples the ATP hydrolysis cycle of eIF4A with strand separation, thereby minimizing non-productive unwinding events. Using duplex substrates with altered GC contents, but with similar predicted thermal stabilities, we further show that the rate of formation of productive unwinding complexes is strongly influenced by the local stability per base pair in addition to the stability of the entire duplex. This finding explains how a change in the GC content of a hairpin while maintaining overall predicted thermal stability is able to influence translation initiation. PMID:21840318

Activating transcription factor 4 regulates stearate-induced vascular calcification.

PubMed

Masuda, Masashi; Ting, Tabitha C; Levi, Moshe; Saunders, Sommer J; Miyazaki-Anzai, Shinobu; Miyazaki, Makoto

2012-08-01

Previously, we reported that stearate, a saturated fatty acid, promotes osteoblastic differentiation and mineralization of vascular smooth muscle cells (VSMC). In this study, we examined the molecular mechanisms by which stearate promotes vascular calcification. ATF4 is a pivotal transcription factor in osteoblastogenesis and endoplasmic reticulum (ER) stress. Increased stearate by either supplementation of exogenous stearic acid or inhibition of stearoyl-CoA desaturase (SCD) by CAY10566 induced ATF4 mRNA, phosphorylated ATF4 protein, and total ATF4 protein. Induction occurred through activation of the PERK-eIF2α pathway, along with increased osteoblastic differentiation and mineralization of VSMCs. Either stearate or the SCD inhibitor but not oleate or other fatty acid treatments also increased ER stress as determined by the expression of p-eIF2α, CHOP, and the spliced form of XBP-1, which were directly correlated with ER stearate levels. ATF4 knockdown by lentiviral ATF4 shRNA blocked osteoblastic differentiation and mineralization induced by stearate and SCD inhibition. Conversely, treatment of VSMCs with an adenovirus containing ATF4 induced vascular calcification. Our results demonstrated that activation of ATF4 mediates vascular calcification induced by stearate.

Activating transcription factor 4 regulates stearate-induced vascular calcification

PubMed Central

Masuda, Masashi; Ting, Tabitha C.; Levi, Moshe; Saunders, Sommer J.; Miyazaki-Anzai, Shinobu; Miyazaki, Makoto

2012-01-01

Previously, we reported that stearate, a saturated fatty acid, promotes osteoblastic differentiation and mineralization of vascular smooth muscle cells (VSMC). In this study, we examined the molecular mechanisms by which stearate promotes vascular calcification. ATF4 is a pivotal transcription factor in osteoblastogenesis and endoplasmic reticulum (ER) stress. Increased stearate by either supplementation of exogenous stearic acid or inhibition of stearoyl-CoA desaturase (SCD) by CAY10566 induced ATF4 mRNA, phosphorylated ATF4 protein, and total ATF4 protein. Induction occurred through activation of the PERK-eIF2α pathway, along with increased osteoblastic differentiation and mineralization of VSMCs. Either stearate or the SCD inhibitor but not oleate or other fatty acid treatments also increased ER stress as determined by the expression of p-eIF2α, CHOP, and the spliced form of XBP-1, which were directly correlated with ER stearate levels. ATF4 knockdown by lentiviral ATF4 shRNA blocked osteoblastic differentiation and mineralization induced by stearate and SCD inhibition. Conversely, treatment of VSMCs with an adenovirus containing ATF4 induced vascular calcification. Our results demonstrated that activation of ATF4 mediates vascular calcification induced by stearate. PMID:22628618

Targeting CCl4 -induced liver fibrosis by RNA interference-mediated inhibition of cyclin E1 in mice.

PubMed

Bangen, Jörg-Martin; Hammerich, Linda; Sonntag, Roland; Baues, Maike; Haas, Ute; Lambertz, Daniela; Longerich, Thomas; Lammers, Twan; Tacke, Frank; Trautwein, Christian; Liedtke, Christian

2017-10-01

Initiation and progression of liver fibrosis requires proliferation and activation of resting hepatic stellate cells (HSCs). Cyclin E1 (CcnE1) is the regulatory subunit of the cyclin-dependent kinase 2 (Cdk2) and controls cell cycle re-entry. We have recently shown that genetic inactivation of CcnE1 prevents activation, proliferation, and survival of HSCs and protects from liver fibrogenesis. The aim of the present study was to translate these findings into preclinical applications using an RNA interference (RNAi)-based approach. CcnE1-siRNA (small interfering RNA) efficiently inhibited CcnE1 gene expression in murine and human HSC cell lines and in primary HSCs, resulting in diminished proliferation and increased cell death. In C57BL/6 wild-type (WT) mice, delivery of stabilized siRNA using a liposome-based carrier targeted approximately 95% of HSCs, 70% of hepatocytes, and 40% of CD45 + cells after single injection. Acute CCl 4 -mediated liver injury in WT mice induced endogenous CcnE1 expression and proliferation of surviving hepatocytes and nonparenchymal cells, including CD45 + leukocytes. Pretreatment with CcnE1-siRNA reverted CcnE1 induction to baseline levels of healthy mice, which was associated with reduced liver injury, diminished proliferation of hepatocytes and leukocytes, and attenuated overall inflammatory response. For induction of liver fibrosis, WT mice were challenged with CCl 4 for 4-6 weeks. Co-treatment with CcnE1-siRNA once a week was sufficient to continuously block CcnE1 expression and cell-cycle activity of hepatocytes and nonparenchymal cells, resulting in significantly ameliorated liver fibrosis and inflammation. Importantly, CcnE1-siRNA also prevented progression of liver fibrosis if applied after onset of chronic liver injury. Therapeutic targeting of CcnE1 in vivo using RNAi is feasible and has high antifibrotic activity. (Hepatology 2017;66:1242-1257). © 2017 by the American Association for the Study of Liver Diseases.

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.

AmphiFoxE4, an amphioxus winged helix/forkhead gene encoding a protein closely related to vertebrate thyroid transcription factor-2: expression during pharyngeal development

NASA Technical Reports Server (NTRS)

Yu, Jr-Kai; Holland, Linda Z.; Jamrich, Milan; Blitz, Ira L.; Hollan, Nicholas D.

2002-01-01

The full-length sequence and developmental expression of amphioxus AmphiFoxE4 are described. Transcripts of the gene are first detected in the pharyngeal endoderm, where the club-shaped gland is forming and subsequently in the definitive gland itself. AmphiFoxE4 is closely related to vertebrate genes encoding the thyroid-specific transcription factor-2 (TTF2), which plays an early developmental role in the morphogenesis of the thyroid gland and a later role in hormone-mediated control of thyroid function. In amphioxus, AmphiFoxE4 expression is not thyroid specific because the club-shaped gland, the only structure expressing the gene, is not homologous to the vertebrate thyroid; instead, the thyroid homologue of amphioxus is a specialized region of the pharyngeal endoderm called the endostyle. We propose that (a) the pharynx of an amphioxus-like ancestor of the vertebrates included a club-shaped gland that expressed FoxE4 as well as an endostyle that did not, and (b) the club-shaped gland soon disappeared in the vertebrate line of descent but (c) not before there was a homeogenetic transfer of FoxE4 expression from the club-shaped gland to the nearby endostyle. Such a transfer could have provided part of the genetic program enabling the endostyle to separate from the pharyngeal endoderm and migrate away as the rudiment of the thyroid gland.

Structure of the E6/E6AP/p53 complex required for HPV-mediated degradation of p53

PubMed Central

Martinez-Zapien, Denise; Ruiz, Francesc Xavier; Poirson, Juline; Mitschler, André; Ramirez-Ramos, Juan; Forster, Anne; Cousido-Siah, Alexandra; Masson, Murielle; Pol, Scott Vande; Podjarny, Alberto; Travé, Gilles; Zanier, Katia

2015-01-01

Summary The p53 pro-apoptotic tumor suppressor is mutated or functionally altered in most cancers. In epithelial tumors induced by “high-risk” mucosal Human Papillomaviruses (hrm-HPVs), including human cervical carcinoma and a growing number of head-and-neck cancers 1, p53 is degraded by the viral oncoprotein E6 2. In this process, E6 binds to a short LxxLL consensus sequence within the cellular ubiquitin ligase E6AP 3. Subsequently, the E6/E6AP heterodimer recruits and degrades p53 4. Neither E6 nor E6AP are separately able to recruit p53 3,5, and the precise mode of assembly of E6, E6AP and p53 is unknown. Here, we solved the crystal structure of a ternary complex comprising full-length HPV16 E6, the LxxLL motif of E6AP and the core domain of p53. The LxxLL motif of E6AP renders the conformation of E6 competent for interaction with p53 by structuring a p53-binding cleft on E6. Mutagenesis of critical positions at the E6-p53 interface disrupts p53 degradation. The E6-binding site of p53 is distal from previously described DNA- and protein-binding surfaces of the core domain. This suggests that, in principle, E6 may avoid competition with cellular factors by targeting both free and bound p53 molecules. The E6/E6AP/p53 complex represents a prototype of viral hijacking of both the ubiquitin-mediated protein degradation pathway and the p53 tumor suppressor pathway. The present structure provides a framework for the design of inhibitory therapeutic strategies against HPV-mediated oncogenesis. PMID:26789255

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

RNF4-mediated polyubiquitination regulates the Fanconi anemia/BRCA pathway.

PubMed

Xie, Jenny; Kim, Hyungjin; Moreau, Lisa A; Puhalla, Shannon; Garber, Judy; Al Abo, Muthana; Takeda, Shunichi; D'Andrea, Alan D

2015-04-01

The Fanconi anemia/BRCA (FA/BRCA) pathway is a DNA repair pathway that is required for excision of DNA interstrand cross-links. The 17 known FA proteins, along with several FA-associated proteins (FAAPs), cooperate in this pathway to detect, unhook, and excise DNA cross-links and to subsequently repair the double-strand breaks generated in the process. In the current study, we identified a patient with FA with a point mutation in FANCA, which encodes a mutant FANCA protein (FANCAI939S). FANCAI939S failed to bind to the FAAP20 subunit of the FA core complex, leading to decreased stability. Loss of FAAP20 binding exposed a SUMOylation site on FANCA at amino acid residue K921, resulting in E2 SUMO-conjugating enzyme UBC9-mediated SUMOylation, RING finger protein 4-mediated (RNF4-mediated) polyubiquitination, and proteasome-mediated degradation of FANCA. Mutation of the SUMOylation site of FANCA rescued the expression of the mutant protein. Wild-type FANCA was also subject to SUMOylation, RNF4-mediated polyubiquitination, and degradation, suggesting that regulated release of FAAP20 from FANCA is a critical step in the normal FA pathway. Consistent with this model, cells lacking RNF4 exhibited interstrand cross-linker hypersensitivity, and the gene encoding RNF4 was epistatic with the other genes encoding members of the FA/BRCA pathway. Together, the results from our study underscore the importance of analyzing unique patient-derived mutations for dissecting complex DNA repair processes.

IB4(+) nociceptors mediate persistent muscle pain induced by GDNF.

PubMed

Alvarez, Pedro; Chen, Xiaojie; Bogen, Oliver; Green, Paul G; Levine, Jon D

2012-11-01

Skeletal muscle is a well-known source of glial cell line-derived neurotrophic factor (GDNF), which can produce mechanical hyperalgesia. Since some neuromuscular diseases are associated with both increased release of GDNF and intense muscle pain, we explored the role of GDNF as an endogenous mediator in muscle pain. Intramuscularly injected GDNF induced a dose-dependent (0.1-10 ng/20 μl) persistent (up to 3 wk) mechanical hyperalgesia in the rat. Once hyperalgesia subsided, injection of prostaglandin E(2) at the site induced a prolonged mechanical hyperalgesia (>72 h) compared with naïve rats (<4 h; hyperalgesic priming). Selective neurotoxic destruction of IB4(+) nociceptors attenuated both GDNF hyperalgesia and hyperalgesic priming. Ergonomic muscular injury induced by eccentric exercise or mechanical vibration increased muscle GDNF levels at 24 h, a time point where rats also exhibited marked muscle hyperalgesia. Intrathecal antisense oligodeoxynucleotides to mRNA encoding GFRα1, the canonical binding receptor for GDNF, reversibly inhibited eccentric exercise- and mechanical vibration-induced muscle hyperalgesia. Finally, electrophysiological recordings from nociceptors innervating the gastrocnemius muscle in anesthetized rats, revealed significant increase in response to sustained mechanical stimulation after local GDNF injection. In conclusion, these data indicate that GDNF plays a role as an endogenous mediator in acute and induction of chronic muscle pain, an effect likely to be produced by GDNF action at GFRα1 receptors located in IB4(+) nociceptors.

Identifying cis-mediators for trans-eQTLs across many human tissues using genomic mediation analysis.

PubMed

Yang, Fan; Wang, Jiebiao; Pierce, Brandon L; Chen, Lin S

2017-11-01

The impact of inherited genetic variation on gene expression in humans is well-established. The majority of known expression quantitative trait loci (eQTLs) impact expression of local genes ( cis -eQTLs). More research is needed to identify effects of genetic variation on distant genes ( trans -eQTLs) and understand their biological mechanisms. One common trans -eQTLs mechanism is "mediation" by a local ( cis ) transcript. Thus, mediation analysis can be applied to genome-wide SNP and expression data in order to identify transcripts that are " cis -mediators" of trans -eQTLs, including those " cis -hubs" involved in regulation of many trans -genes. Identifying such mediators helps us understand regulatory networks and suggests biological mechanisms underlying trans -eQTLs, both of which are relevant for understanding susceptibility to complex diseases. The multitissue expression data from the Genotype-Tissue Expression (GTEx) program provides a unique opportunity to study cis -mediation across human tissue types. However, the presence of complex hidden confounding effects in biological systems can make mediation analyses challenging and prone to confounding bias, particularly when conducted among diverse samples. To address this problem, we propose a new method: Genomic Mediation analysis with Adaptive Confounding adjustment (GMAC). It enables the search of a very large pool of variables, and adaptively selects potential confounding variables for each mediation test. Analyses of simulated data and GTEx data demonstrate that the adaptive selection of confounders by GMAC improves the power and precision of mediation analysis. Application of GMAC to GTEx data provides new insights into the observed patterns of cis -hubs and trans -eQTL regulation across tissue types. © 2017 Yang et al.; Published by Cold Spring Harbor Laboratory Press.

The ubiquitin ligase Nedd4 mediates oxidized low-density lipoprotein-induced downregulation of insulin-like growth factor-1 receptor

PubMed Central

Higashi, Yusuke; Sukhanov, Sergiy; Parthasarathy, Sampath; Delafontaine, Patrice

2008-01-01

Oxidized low-density lipoprotein (LDL) is proatherogenic and induces smooth muscle cell apoptosis, which contributes to atherosclerotic plaque destabilization. We showed previously that oxidized LDL downregulates insulin-like growth factor-1 receptor in human smooth muscle cells and that this is critical for induction of apoptosis. To identify mechanisms, we exposed smooth muscle cells to 60 μg/ml oxidized LDL or native LDL and assessed insulin-like growth factor-1 receptor mRNA levels, protein synthesis rate, and receptor protein stability. Oxidized LDL decreased insulin-like growth factor-1 receptor mRNA levels by 30% at 8 h compared with native LDL, and this decrease was maintained for up to 20 h. However, insulin-like growth factor-1 receptor protein synthesis rate was not altered by oxidized LDL. Pulse-chase labeling experiments revealed that oxidized LDL reduced insulin-like growth factor-1 receptor protein half-life to 12.2 ± 1.7 h from 24.4 ± 4.7 h with native LDL. This destabilization of insulin-like growth factor-1 receptor protein was accompanied by enhanced receptor ubiquitination. Overexpression of dominant-negative Nedd4 prevented oxidized LDL-induced downregulation of insulin-like growth factor-1 receptor, suggesting that Nedd4 was the ubiquitin ligase that mediated receptor downregulation. However, the proteasome inhibitors lactacystin, MG-132, and proteasome inhibitor-1 failed to block oxidized LDL-induced downregulation of insulin-like growth factor-1 receptor. Thus oxidized LDL downregulates insulin-like growth factor-1 receptor by destabilizing the protein via Nedd4-enhanced ubiquitination, leading to degradation via a proteasome-independent pathway. This finding provides novel insights into oxidized LDL-triggered oxidant signaling and mechanisms of smooth muscle cell depletion that contribute to plaque destabilization and coronary events. PMID:18723765

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

How Is the Effect of Adolescent E-cigarette Use on Smoking Onset Mediated: A Longitudinal Analysis

PubMed Central

Wills, Thomas A.; Gibbons, Frederick X.; Sargent, James D.; Schweitzer, Rebecca J.

2016-01-01

E-cigarette use by adolescents has been related to onset of cigarette smoking but there is little knowledge about the process(es) through which this occurs. Accordingly, we tested the role of cognitive and social factors for mediating the relation between e-cigarette use and smoking onset. A school-based survey was conducted with a baseline sample of 2,338 students in Hawaii (9th and 10th graders, mean age 14.7 years) who were surveyed in 2013 (Time 1, T1) and followed up 1 year later (Time 2, T2). We assessed e-cigarette use, cigarette smoking, demographic covariates, and four hypothesized mediators: smoking-related expectancies, prototypes, and peer affiliations as well as marijuana use. The primary structural modeling analysis, based on initial never-smokers, used an autoregressive model (entering T2 mediator values adjusted for T1 values) to test for mediational pathways in the relation between e-cigarette use at T1 and cigarette smoking status at T2. Results showed that e-cigarette use was related to all of the mediators and tests of indirect effects indicated that changes in expectancies, affiliations, and marijuana use were significant pathways in the relation between e-cigarette use and smoking onset. A direct effect from e-cigarette use to smoking onset was nonsignificant. Findings were replicated across autoregressive and prospective models. We conclude that the relation between adolescent e-cigarette use and smoking onset is in part attributable to cognitive and social processes that follow from e-cigarette use. Further research is needed to understand the relative role of nicotine and psychosocial factors in smoking onset. PMID:27669093

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

Ubiquitin-dependent Regulation of Phospho-AKT Dynamics by the Ubiquitin E3 Ligase, NEDD4-1, in the Insulin-like Growth Factor-1 Response*

PubMed Central

Fan, Chuan-Dong; Lum, Michelle A.; Xu, Chao; Black, Jennifer D.; Wang, Xinjiang

2013-01-01

AKT is a critical effector kinase downstream of the PI3K pathway that regulates a plethora of cellular processes including cell growth, death, differentiation, and migration. Mechanisms underlying activated phospho-AKT (pAKT) translocation to its action sites remain unclear. Here we show that NEDD4-1 is a novel E3 ligase that specifically regulates ubiquitin-dependent trafficking of pAKT in insulin-like growth factor (IGF)-1 signaling. NEDD4-1 physically interacts with AKT and promotes HECT domain-dependent ubiquitination of exogenous and endogenous AKT. NEDD4-1 catalyzes K63-type polyubiquitin chain formation on AKT in vitro. Plasma membrane binding is the key step for AKT ubiquitination by NEDD4-1 in vivo. Ubiquitinated pAKT translocates to perinuclear regions, where it is released into the cytoplasm, imported into the nucleus, or coupled with proteasomal degradation. IGF-1 signaling specifically stimulates NEDD4-1-mediated ubiquitination of pAKT, without altering total AKT ubiquitination. A cancer-derived plasma membrane-philic mutant AKT(E17K) is more effectively ubiquitinated by NEDD4-1 and more efficiently trafficked into the nucleus compared with wild type AKT. This study reveals a novel mechanism by which a specific E3 ligase is required for ubiquitin-dependent control of pAKT dynamics in a ligand-specific manner. PMID:23195959

C/EBPβ-LAP*/LAP Expression Is Mediated by RSK/eIF4B-Dependent Signalling and Boosted by Increased Protein Stability in Models of Monocytic Differentiation

PubMed Central

Christmann, Martin; Friesenhagen, Judith; Westphal, Andreas; Pietsch, Daniel; Brand, Korbinian

2015-01-01

The transcription factor C/EBPβ plays a key role in monocytic differentiation and inflammation. Its small isoform LIP is associated with proliferation at early premonocytic developmental stages and regulated via mTOR-dependent signalling. During later stages of (pre)monocytic differentiation there is a considerable increase in the large C/EBPβ isoforms LAP*/LAP which inhibit proliferation thus supporting terminal differentiation. Here, we showed in different models of monocytic differentiation that this dramatic increase in the LAP*/LAP protein and LAP/LIP ratio was accompanied by an only modest/retarded mRNA increase suggesting an important role for (post)translational mechanisms. We found that LAP*/LAP formation was induced via MEK/RSK-dependent cascades, whereas mTOR/S6K1 were not involved. Remarkably, LAP*/LAP expression was dependent on phosphorylated eIF4B, an acceleratory protein of RNA helicase eIF4A. PKR inhibition reduced the expression of eIF4B and C/EBPβ in an eIF2α-independent manner. Furthermore, under our conditions a marked stabilisation of LAP*/LAP protein occurred, accompanied by reduced chymotrypsin-like proteasome/calpain activities and increased calpastatin levels. Our study elucidates new signalling pathways inducing LAP*/LAP expression and indicates new alternative PKR functions in monocytes. The switch from mTOR- to RSK-mediated signalling to orchestrate eIF4B-dependent LAP*/LAP translation, accompanied by increased protein stability but only small mRNA changes, may be a prototypical example for the regulation of protein expression during selected processes of differentiation/proliferation. PMID:26646662

A critical role for transcription factor Smad4 in T cell function independent of transforming growth factor beta receptor signaling

PubMed Central

Gu, Ai-Di; Zhang, Song; Wang, Yunqi; Xiong, Hui; Curtis, Thomas A.; Wan, Yisong Y.

2014-01-01

Summary Transforming growth factor-beta (TGF-β) suppresses T cell function to maintain self-tolerance and to promote tumor immune evasion. Yet how Smad4, a transcription factor component of TGF-β signaling, regulates T cell function remains unclear. Here we have demonstrated an essential role for Smad4 in promoting T cell function during autoimmunity and anti-tumor immunity. Smad4 deletion rescued the lethal autoimmunity resulting from transforming growth factor-beta receptor (TGF-βR) deletion and compromised T-cell-mediated tumor rejection. While Smad4 was dispensable for T cell generation, homeostasis and effector function, it was essential for T cell proliferation following activation in vitro and in vivo. The transcription factor Myc was identified to mediate Smad4-controlled T cell proliferation. This study thus reveals a requirement of Smad4 for T-cell-mediated autoimmunity and tumor rejection, which is beyond the current paradigm. It highlights a TGF-βR-independent role for Smad4 in promoting T cell function, autoimmunity and anti-tumor immunity. PMID:25577439

Glucose Deprivation Induces ATF4-Mediated Apoptosis through TRAIL Death Receptors

PubMed Central

Iurlaro, Raffaella; Püschel, Franziska; León-Annicchiarico, Clara Lucía; O'Connor, Hazel; Martin, Seamus J.; Palou-Gramón, Daniel; Lucendo, Estefanía

2017-01-01

ABSTRACT Metabolic stress occurs frequently in tumors and in normal tissues undergoing transient ischemia. Nutrient deprivation triggers, among many potential cell death-inducing pathways, an endoplasmic reticulum (ER) stress response with the induction of the integrated stress response transcription factor ATF4. However, how this results in cell death remains unknown. Here we show that glucose deprivation triggered ER stress and induced the unfolded protein response transcription factors ATF4 and CHOP. This was associated with the nontranscriptional accumulation of TRAIL receptor 1 (TRAIL-R1) (DR4) and with the ATF4-mediated, CHOP-independent induction of TRAIL-R2 (DR5), suggesting that cell death in this context may involve death receptor signaling. Consistent with this, the ablation of TRAIL-R1, TRAIL-R2, FADD, Bid, and caspase-8 attenuated cell death, although the downregulation of TRAIL did not, suggesting ligand-independent activation of TRAIL receptors. These data indicate that stress triggered by glucose deprivation promotes the ATF4-dependent upregulation of TRAIL-R2/DR5 and TRAIL receptor-mediated cell death. PMID:28242652

Allergen endotoxins induce T-cell-dependent and non-IgE-mediated nasal hypersensitivity in mice.

PubMed

Iwasaki, Naruhito; Matsushita, Kazufumi; Fukuoka, Ayumi; Nakahira, Masakiyo; Matsumoto, Makoto; Akasaki, Shoko; Yasuda, Koubun; Shimizu, Takeshi; Yoshimoto, Tomohiro

2017-01-01

Allergen-mediated cross-linking of IgE on mast cells/basophils is a well-recognized trigger for type 1 allergic diseases such as allergic rhinitis (AR). However, allergens may not be the sole trigger for AR, and several allergic-like reactions are induced by non-IgE-mediated mechanisms. We sought to describe a novel non-IgE-mediated, endotoxin-triggered nasal type-1-hypersensitivity-like reaction in mice. To investigate whether endotoxin affects sneezing responses, mice were intraperitoneally immunized with ovalbumin (OVA), then nasally challenged with endotoxin-free or endotoxin-containing OVA. To investigate the role of T cells and mechanisms of the endotoxin-induced response, mice were adoptively transferred with in vitro-differentiated OVA-specific T H 2 cells, then nasally challenged with endotoxin-free or endotoxin-containing OVA. Endotoxin-containing, but not endotoxin-free, OVA elicited sneezing responses in mice independent from IgE-mediated signaling. OVA-specific T H 2 cell adoptive transfer to mice demonstrated that local activation of antigen-specific T H 2 cells was required for the response. The Toll-like receptor 4-myeloid differentiation factor 88 signaling pathway was indispensable for endotoxin-containing OVA-elicited rhinitis. In addition, LPS directly triggered sneezing responses in OVA-specific T H 2-transferred and nasally endotoxin-free OVA-primed mice. Although antihistamines suppressed sneezing responses, mast-cell/basophil-depleted mice had normal sneezing responses to endotoxin-containing OVA. Clodronate treatment abrogated endotoxin-containing OVA-elicited rhinitis, suggesting the involvement of monocytes/macrophages in this response. Antigen-specific nasal activation of CD4 + T cells followed by endotoxin exposure induces mast cell/basophil-independent histamine release in the nose that elicits sneezing responses. Thus, environmental or nasal residential bacteria may exacerbate AR symptoms. In addition, this novel phenomenon might

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.

RNF4-mediated polyubiquitination regulates the Fanconi anemia/BRCA pathway

PubMed Central

Xie, Jenny; Kim, Hyungjin; Moreau, Lisa A.; Puhalla, Shannon; Garber, Judy; Al Abo, Muthana; Takeda, Shunichi; D’Andrea, Alan D.

2015-01-01

The Fanconi anemia/BRCA (FA/BRCA) pathway is a DNA repair pathway that is required for excision of DNA interstrand cross-links. The 17 known FA proteins, along with several FA-associated proteins (FAAPs), cooperate in this pathway to detect, unhook, and excise DNA cross-links and to subsequently repair the double-strand breaks generated in the process. In the current study, we identified a patient with FA with a point mutation in FANCA, which encodes a mutant FANCA protein (FANCAI939S). FANCAI939S failed to bind to the FAAP20 subunit of the FA core complex, leading to decreased stability. Loss of FAAP20 binding exposed a SUMOylation site on FANCA at amino acid residue K921, resulting in E2 SUMO-conjugating enzyme UBC9-mediated SUMOylation, RING finger protein 4–mediated (RNF4-mediated) polyubiquitination, and proteasome-mediated degradation of FANCA. Mutation of the SUMOylation site of FANCA rescued the expression of the mutant protein. Wild-type FANCA was also subject to SUMOylation, RNF4-mediated polyubiquitination, and degradation, suggesting that regulated release of FAAP20 from FANCA is a critical step in the normal FA pathway. Consistent with this model, cells lacking RNF4 exhibited interstrand cross-linker hypersensitivity, and the gene encoding RNF4 was epistatic with the other genes encoding members of the FA/BRCA pathway. Together, the results from our study underscore the importance of analyzing unique patient-derived mutations for dissecting complex DNA repair processes. PMID:25751062

Structure of the exportin Xpo4 in complex with RanGTP and the hypusine-containing translation factor eIF5A

PubMed Central

Aksu, Metin; Trakhanov, Sergei; Görlich, Dirk

2016-01-01

Xpo4 is a bidirectional nuclear transport receptor that mediates nuclear export of eIF5A and Smad3 as well as import of Sox2 and SRY. How Xpo4 recognizes such a variety of cargoes is as yet unknown. Here we present the crystal structure of the RanGTP·Xpo4·eIF5A export complex at 3.2 Å resolution. Xpo4 has a similar structure as CRM1, but the NES-binding site is occluded, and a new interaction site evolved that recognizes both globular domains of eIF5A. eIF5A contains hypusine, a unique amino acid with two positive charges, which is essential for cell viability and eIF5A function in translation. The hypusine docks into a deep, acidic pocket of Xpo4 and is thus a critical element of eIF5A's complex export signature. This further suggests that Xpo4 recognizes other cargoes differently, and illustrates how Xpo4 suppresses – in a chaperone-like manner – undesired interactions of eIF5A inside nuclei. PMID:27306458

Plasma membrane calcium ATPase isoform 4 inhibits vascular endothelial growth factor-mediated angiogenesis through interaction with calcineurin.

PubMed

Baggott, Rhiannon R; Alfranca, Arantzazu; López-Maderuelo, Dolores; Mohamed, Tamer M A; Escolano, Amelia; Oller, Jorge; Ornes, Beatriz C; Kurusamy, Sathishkumar; Rowther, Farjana B; Brown, James E; Oceandy, Delvac; Cartwright, Elizabeth J; Wang, Weiguang; Gómez-del Arco, Pablo; Martínez-Martínez, Sara; Neyses, Ludwig; Redondo, Juan Miguel; Armesilla, Angel Luis

2014-10-01

Vascular endothelial growth factor (VEGF) has been identified as a crucial regulator of physiological and pathological angiogenesis. Among the intracellular signaling pathways triggered by VEGF, activation of the calcineurin/nuclear factor of activated T cells (NFAT) signaling axis has emerged as a critical mediator of angiogenic processes. We and others previously reported a novel role for the plasma membrane calcium ATPase (PMCA) as an endogenous inhibitor of the calcineurin/NFAT pathway, via interaction with calcineurin, in cardiomyocytes and breast cancer cells. However, the functional significance of the PMCA/calcineurin interaction in endothelial pathophysiology has not been addressed thus far. Using in vitro and in vivo assays, we here demonstrate that the interaction between PMCA4 and calcineurin in VEGF-stimulated endothelial cells leads to downregulation of the calcineurin/NFAT pathway and to a significant reduction in the subsequent expression of the NFAT-dependent, VEGF-activated, proangiogenic genes RCAN1.4 and Cox-2. PMCA4-dependent inhibition of calcineurin signaling translates into a reduction in endothelial cell motility and blood vessel formation that ultimately impairs in vivo angiogenesis by VEGF. Given the importance of the calcineurin/NFAT pathway in the regulation of pathological angiogenesis, targeted modulation of PMCA4 functionality might open novel therapeutic avenues to promote or attenuate new vessel formation in diseases that occur with angiogenesis. © 2014 American Heart Association, Inc.

Cycles of Ubiquitination and Deubiquitination Critically Regulate Growth Factor-Mediated Activation of Akt Signaling

PubMed Central

Yang, Wei-Lei; Jin, Guoxiang; Li, Chien-Feng; Jeong, Yun Seong; Moten, Asad; Xu, Dazhi; Feng, Zizhen; Chen, Wei; Cai, Zhen; Darnay, Bryant; Gu, Wei; Lin, Hui-Kuan

2013-01-01

K63-linked ubiquitination of Akt is a posttranslational modification that plays a critical role in growth factor-mediated membrane recruitment and activation of Akt. Although E3 ligases involved in growth factor-induced Akt ubiquitination have been defined, the deubiquitinating enzyme (DUB) that triggers deubiquitination of Akt and the function of Akt deubiquitination remain largely unclear. Here, we showed that CYLD was a DUB for Akt and suppressed growth factor-mediated Akt ubiquitination and activation. CYLD directly removed ubiquitin moieties on Akt under serum-starved conditions. CYLD dissociated from Akt upon growth factor stimulation, thereby allowing E3 ligases to induce ubiquitination and activation of Akt. CYLD deficiency also promoted cancer cell proliferation, survival, glucose uptake and growth of prostate tumors. Our findings reveal the crucial role of cycles of ubiquitination and deubiquitination of Akt in its membrane recruitment and activation, and further identifies CYLD as a molecular switch for these processes. PMID:23300340

A systematic review: can one prescribe carbapenems to patients with IgE-mediated allergy to penicillins or cephalosporins?

PubMed

Kula, Brittany; Djordjevic, Gordana; Robinson, Joan L

2014-10-15

Cross-reactivity between penicillins or cephalosporins and carbapenems is anticipated as all have a beta lactam ring. However, the true incidence of immunoglobulin (Ig)E-mediated cross-reactivity is not known. A systematic review was conducted to collect and combine all published data on children and adults reported to have a clinical history of IgE-mediated hypersensitivity to a penicillin and/or cephalosporin who were subsequently given a carbapenem. Reactions were classified as proven, suspected, or possible IgE-mediated and non-IgE-mediated. Ten studies and 12 case reports describing 854 participants fit the study criteria. For patients with previous proven, suspected, or possible IgE-mediated penicillin reactions (N = 838), the incidence of any type of suspected hypersensitivity reaction to a carbapenem was 36/838 (4.3%; 95% confidence interval [CI], 3.1%-5.9%) and the incidence of proven (1/838), suspected (0/838), or possible (19/838) IgE-mediated reactions was 20/838 (2.4%; 95% CI, 1.6%-3.7%). Of the subset of patients with positive penicillin skin tests (n = 295), only 1 had a hypersensitivity reaction (0.3%; 95% CI, .06%-1.9%), and this was a possible IgE-mediated reaction. For patients with previous proven, suspected, or possible IgE-mediated cephalosporin reactions (N = 12), the incidence of any type of hypersensitivity reaction to a carbapenem was 3/12 (25%); this included 2 non-IgE-mediated reactions and 1 possible IgE-mediated reaction. The cross-reactivity between penicillins and carbapenems for IgE-mediated reactions is very low, but caution is still advised. Cross-reactivity rates may be higher between cephalosporins and carbapenems; however, minimal data are available. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Apolipoprotein E3 (ApoE3) but Not ApoE4 Protects against Synaptic Loss through Increased Expression of Protein Kinase Cϵ

PubMed Central

Sen, Abhik; Alkon, Daniel L.; Nelson, Thomas J.

2012-01-01

Synaptic loss is the earliest pathological change in Alzheimer disease (AD) and is the pathological change most directly correlated with the degree of dementia. ApoE4 is the major genetic risk factor for the age-dependent form of AD, which accounts for 95% of cases. Here we show that in synaptic networks formed from primary hippocampal neurons in culture, apoE3, but not apoE4, prevents the loss of synaptic networks produced by amyloid β oligomers (amylospheroids). Specific activators of PKCϵ, such as 8-(2-(2-pentyl-cyclopropylmethyl)-cyclopropyl)-octanoic acid methyl ester and bryostatin 1, protected against synaptic loss by amylospheroids, whereas PKCϵ inhibitors blocked this synaptic protection and also blocked the protection by apoE3. Blocking LRP1, an apoE receptor on the neuronal membrane, also blocked the protection by apoE. ApoE3, but not apoE4, induced the synthesis of PKCϵ mRNA and expression of the PKCϵ protein. Amyloid β specifically blocked the expression of PKCϵ but had no effect on other isoforms. These results suggest that protection against synaptic loss by apoE is mediated by a novel intracellular PKCϵ pathway. This apoE pathway may account for much of the protective effect of apoE and reduced risk for the age-dependent form of AD. This finding supports the potential efficacy of newly developed therapeutics for AD. PMID:22427674

HPV16 and 18 genome amplification show different E4-dependence, with 16E4 enhancing E1 nuclear accumulation and replicative efficiency via its cell cycle arrest and kinase activation functions

PubMed Central

Jackson, Deborah; Mahmood, Radma

2017-01-01

To clarify E1^E4’s role during high-risk HPV infection, the E4 proteins of HPV16 and 18 were compared side by side using an isogenic keratinocyte differentiation model. While no effect on cell proliferation or viral genome copy number was observed during the early phase of either virus life cycle, time-course experiments showed that viral genome amplification and L1 expression were differently affected upon differentiation, with HPV16 showing a much clearer E4 dependency. Although E4 loss never completely abolished genome amplification, its more obvious contribution in HPV16 focused our efforts on 16E4. As previously suggested, in the context of the virus life cycle, 16E4s G2-arrest capability was found to contribute to both genome amplification success and L1 accumulation. Loss of 16E4 also lead to a reduced maintenance of ERK, JNK and p38MAPK activity throughout the genome amplifying cell layers, with 16E4 (but not 18E4) co-localizing precisely with activated cytoplasmic JNK in both wild type raft tissue, and HPV16-induced patient biopsy tissue. When 16E1 was co-expressed with E4, as occurs during genome amplification in vivo, the E1 replication helicase accumulated preferentially in the nucleus, and in transient replication assays, E4 stimulated viral genome amplification. Interestingly, a 16E1 mutant deficient in its regulatory phosphorylation sites no longer accumulated in the nucleus following E4 co-expression. E4-mediated stabilisation of 16E2 was also apparent, with E2 levels declining in organotypic raft culture when 16E4 was absent. These results suggest that 16E4-mediated enhancement of genome amplification involves its cell cycle inhibition and cellular kinase activation functions, with E4 modifying the activity and function of viral replication proteins including E1. These activities of 16E4, and the different kinase patterns seen here with HPV18, 31 and 45, may reflect natural differences in the biology and tropisms of these viruses, as well as

The nuclear factor κB inhibitor (E)-2-fluoro-4'-methoxystilbene inhibits firefly luciferase.

PubMed

Braeuning, Albert; Vetter, Silvia

2012-12-01

Photinus pyralis (firefly) luciferase is widely used as a reporter system to monitor alterations in gene promoter and/or signalling pathway activities in vitro. The enzyme catalyses the formation of oxyluciferin from D-luciferin in an ATP-consuming reaction involving photon emission. The purpose of the present study was to characterize the luciferase-inhibiting potential of (E)-2-fluoro-4'-methoxystilbene, which is known as a potent inhibitor of the NF-κB (nuclear factor κB) signalling pathway that is used to modulate the NF-κB signalling pathway in vitro. Results show that (E)-2-fluoro-4'-methoxystilbene effectively inhibits firefly luciferase activity in cell lysates and living cells in a non-competitive manner with respect to the luciferase substrates D-luciferin and ATP. By contrast, the compound has no effect on Renilla and Gaussia luciferases. The mechanism of firefly luciferase inhibition by (E)-2-fluoro-4'-methoxystilbene, as well as its potency is comparable to its structure analogue resveratrol. The in vitro use of trans-stilbenes such as (E)-2-fluoro-4'-methoxystilbene or resveratrol compromises firefly luciferase reporter assays as well as ATP/luciferase-based cell viability assays.

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.

Identifying cis-mediators for trans-eQTLs across many human tissues using genomic mediation analysis

PubMed Central

Yang, Fan; Wang, Jiebiao; Pierce, Brandon L.; Chen, Lin S.

2017-01-01

The impact of inherited genetic variation on gene expression in humans is well-established. The majority of known expression quantitative trait loci (eQTLs) impact expression of local genes (cis-eQTLs). More research is needed to identify effects of genetic variation on distant genes (trans-eQTLs) and understand their biological mechanisms. One common trans-eQTLs mechanism is “mediation” by a local (cis) transcript. Thus, mediation analysis can be applied to genome-wide SNP and expression data in order to identify transcripts that are “cis-mediators” of trans-eQTLs, including those “cis-hubs” involved in regulation of many trans-genes. Identifying such mediators helps us understand regulatory networks and suggests biological mechanisms underlying trans-eQTLs, both of which are relevant for understanding susceptibility to complex diseases. The multitissue expression data from the Genotype-Tissue Expression (GTEx) program provides a unique opportunity to study cis-mediation across human tissue types. However, the presence of complex hidden confounding effects in biological systems can make mediation analyses challenging and prone to confounding bias, particularly when conducted among diverse samples. To address this problem, we propose a new method: Genomic Mediation analysis with Adaptive Confounding adjustment (GMAC). It enables the search of a very large pool of variables, and adaptively selects potential confounding variables for each mediation test. Analyses of simulated data and GTEx data demonstrate that the adaptive selection of confounders by GMAC improves the power and precision of mediation analysis. Application of GMAC to GTEx data provides new insights into the observed patterns of cis-hubs and trans-eQTL regulation across tissue types. PMID:29021290

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

K48-linked KLF4 ubiquitination by E3 ligase Mule controls T-cell proliferation and cell cycle progression.

PubMed

Hao, Zhenyue; Sheng, Yi; Duncan, Gordon S; Li, Wanda Y; Dominguez, Carmen; Sylvester, Jennifer; Su, Yu-Wen; Lin, Gloria H Y; Snow, Bryan E; Brenner, Dirk; You-Ten, Annick; Haight, Jillian; Inoue, Satoshi; Wakeham, Andrew; Elford, Alisha; Hamilton, Sara; Liang, Yi; Zúñiga-Pflücker, Juan C; He, Housheng Hansen; Ohashi, Pamela S; Mak, Tak W

2017-01-13

T-cell proliferation is regulated by ubiquitination but the underlying molecular mechanism remains obscure. Here we report that Lys-48-linked ubiquitination of the transcription factor KLF4 mediated by the E3 ligase Mule promotes T-cell entry into S phase. Mule is elevated in T cells upon TCR engagement, and Mule deficiency in T cells blocks proliferation because KLF4 accumulates and drives upregulation of its transcriptional targets E2F2 and the cyclin-dependent kinase inhibitors p21 and p27. T-cell-specific Mule knockout (TMKO) mice develop exacerbated experimental autoimmune encephalomyelitis (EAE), show impaired generation of antigen-specific CD8 + T cells with reduced cytokine production, and fail to clear LCMV infections. Thus, Mule-mediated ubiquitination of the novel substrate KLF4 regulates T-cell proliferation, autoimmunity and antiviral immune responses in vivo.

The Candida albicans Pho4 Transcription Factor Mediates Susceptibility to Stress and Influences Fitness in a Mouse Commensalism Model

PubMed Central

Urrialde, Verónica; Prieto, Daniel; Pla, Jesús; Alonso-Monge, Rebeca

2016-01-01

The Pho4 transcription factor is required for growth under low environmental phosphate concentrations in Saccharomyces cerevisiae. A characterization of Candida albicans pho4 mutants revealed that these cells are more susceptible to both osmotic and oxidative stress and that this effect is diminished in the presence of 5% CO2 or anaerobiosis, reflecting the relevance of oxygen metabolism in the Pho4-mediated response. A pho4 mutant was as virulent as wild type strain when assayed in the Galleria mellonella infection model and was even more resistant to murine macrophages in ex vivo killing assays. The lack of Pho4 neither impairs the ability to colonize the murine gut nor alters the localization in the gastrointestinal tract. However, we found that Pho4 influenced the colonization of C. albicans in the mouse gut in competition assays; pho4 mutants were unable to attain high colonization levels when inoculated simultaneously with an isogenic wild type strain. Moreover, pho4 mutants displayed a reduced adherence to the intestinal mucosa in a competitive ex vivo assays with wild type cells. In vitro competitive assays also revealed defects in fitness for this mutant compared to the wild type strain. Thus, Pho4, a transcription factor involved in phosphate metabolism, is required for adaptation to stress and fitness in C. albicans. PMID:27458452

Egr-1 and serum response factor are involved in growth factors- and serum-mediated induction of E2-EPF UCP expression that regulates the VHL-HIF pathway.

PubMed

Lim, Jung Hwa; Jung, Cho-Rok; Lee, Chan-Hee; Im, Dong-Soo

2008-11-01

E2-EPF ubiquitin carrier protein (UCP) has been shown to be highly expressed in common human cancers and target von Hippel-Lindau (VHL) for proteosomal degradation in cells, thereby stabilizing hypoxia-inducible factor (HIF)-1alpha. Here, we investigated cellular factors that regulate the expression of UCP gene. Promoter deletion assay identified binding sites for early growth response-1 (Egr-1) and serum response factor (SRF) in the UCP promoter. Hepatocyte or epidermal growth factor (EGF), or phorbol 12-myristate 13-acetate induced UCP expression following early induction of Egr-1 expression in HeLa cells. Serum increased mRNA and protein levels of SRF and UCP in the cell. By electrophoretic mobility shift and chromatin immunoprecipitation assays, sequence-specific DNA-binding of Egr-1 and SRF to the UCP promoter was detected in nuclear extracts from HeLa cells treated with EGF and serum, respectively. Overexpression of Egr-1 or SRF increased UCP expression. RNA interference-mediated depletion of endogenous Egr-1 or SRF impaired EGF- or serum-mediated induction of UCP expression, which was required for cancer cell proliferation. Systemic delivery of EGF into mice also increased UCP expression following early induction of Egr-1 expression in mouse liver. The induced UCP expression by the growth factors or serum increased HIF-1alpha protein level under non-hypoxic conditions, suggesting that the Egr-1/SRF-UCP-VHL pathway is in part responsible for the increased HIF-1alpha protein level in vitro and in vivo. Thus, growth factors and serum induce expression of Egr-1 and SRF, respectively, which in turn induces UCP expression that positively regulates cancer cell growth.

CHMP6 and VPS4A mediate recycling of Ras to the plasma membrane to promote growth factor signaling

PubMed Central

Zheng, Ze-Yi; Cheng, Chiang-Min; Fu, Xin-Rong; Chen, Liuh-Yow; Xu, Lizhong; Terrillon, Sonia; Wong, Stephen T.; Bar-Sagi, Dafna; Songyang, Zhou; Chang, Eric C.

2011-01-01

While Ras is well-known to function on the plasma membrane (PM) to mediate growth factor signaling, increasing evidence suggests that Ras has complex roles in the cytoplasm. To uncover these roles, we screened a cDNA library and isolated H-Ras-binding proteins that also influence Ras functions. Many isolated proteins regulate trafficking involving endosomes; CHMP6/VPS20 and VPS4A, which interact with ESCRT-III, were chosen for further study. We showed that the binding is direct and occurs in endosomes. Furthermore, the binding is most efficient when H-Ras has a functional effector-binding-loop and is GTP-bound and ubiquitylated. CHMP6 and VPS4A also bound N-Ras, but not K-Ras. Repressing CHMP6 and VPS4A blocked Ras-induced transformation, which correlated with inefficient Ras localization to the PM as measured by cell fractionation and photobleaching. Moreover, silencing CHMP6 and VPS4A also blocked EGFR recycling. These data suggest that Ras interacts with key ESCRT-III components to promote recycling of itself and EGFR back to the PM to create a positive feedback loop to enhance growth factor signaling. PMID:22231449

Advancing coalition theory: the effect of coalition factors on community capacity mediated by member engagement

PubMed Central

Kegler, Michelle C.; Swan, Deanne W.

2012-01-01

Community coalitions have the potential to enhance a community’s capacity to engage in effective problem solving for a range of community concerns. Although numerous studies have documented correlations between member engagement and coalition processes and structural characteristics, fewer have examined associations between coalition factors and community capacity outcomes. The current study uses data from an evaluation of the California Healthy Cities and Communities program to examine pathways between coalition factors (i.e. membership, processes), member engagement (i.e. participation, satisfaction) and community capacity as hypothesized by the Community Coalition Action Theory (CCAT). Surveys were completed by 231 members of 19 healthy cities and communities coalitions. Multilevel mediation analyses were used to examine possible mediating effects of member engagement on three community capacity indicators: new skills, sense of community and social capital. Results generally supported CCAT. Member engagement mediated the effects of leadership and staffing on community capacity outcomes. Results also showed that member engagement mediated several relationships between process variables (i.e. task focus, cohesion) and community capacity, but several unmediated direct effects were also observed. This suggests that although member engagement does explain some relationships, it alone is not sufficient to explain how coalition processes influence indicators of community capacity. PMID:21911845

Paradoxical effects of 137Cs irradiation on pharmacological stimulation of reactive oxygen species in hippocampal slices from apoE2 and apoE4 mice.

PubMed

Villasana, Laura E; Akinyeke, Tunde; Weber, Sydney; Raber, Jacob

2017-09-29

In humans, apoE, which plays a role in repair, is expressed in three isoforms: E2, E3, and E4. E4 is a risk factor for age-related cognitive decline (ACD) and Alzheimer's disease (AD), particularly in women. In contrast, E2 is a protective factor for ACD and AD. E2 and E4 might also differ in their response to cranial 137 Cs irradiation, a form of radiation typically used in a clinical setting for the treatment of cancer. This might be mediated by reactive oxygen species (ROS) in an-apoE isoform-dependent fashion. E2 and E4 female mice received sham-irradiation or cranial irradiation at 8 weeks of age and a standard mouse chow or a diet supplemented with the antioxidant alpha-lipoic acid (ALA) starting at 6 weeks of age. Behavioral and cognitive performance of the mice were assessed 12 weeks later. Subsequently, the generation of ROS in hippocampal slices was analyzed. Compared to sham-irradiated E4 mice, irradiated E4 mice showed enhanced spatial memory in the water maze. This was associated with increased hippocampal PMA-induction of ROS. Similar effects were not seen in E2 mice. Irradiation increased endogenous hippocampal ROS levels in E2 mice while decreasing those in E4 mice. NADPH activity and MnSOD levels were higher in sham-irradiated E2 than E4 mice. Irradiation increased NADPH activity and MnSOD levels in hemi brains of E4 mice but not in those of E2 mice. ALA did not affect behavioral and cognitive performance or hippocampal formation of ROS in either genotype. Thus, apoE isoforms modulate the radiation response.

Alzheimer disease genetic risk factor APOE e4 and cognitive abilities in 111,739 UK Biobank participants.

PubMed

Lyall, Donald M; Ward, Joey; Ritchie, Stuart J; Davies, Gail; Cullen, Breda; Celis, Carlos; Bailey, Mark E S; Anderson, Jana; Evans, Jon; Mckay, Daniel F; Mcintosh, Andrew M; Sattar, Naveed; Smith, Daniel J; Deary, Ian J; Pell, Jill P

2016-07-01

the apolipoprotein (APOE) e4 locus is a genetic risk factor for dementia. Carriers of the e4 allele may be more vulnerable to conditions that are independent risk factors for cognitive decline, such as cardiometabolic diseases. we tested whether any association with APOE e4 status on cognitive ability was larger in older ages or in those with cardiometabolic diseases. UK Biobank includes over 500,000 middle- and older aged adults who have undergone detailed medical and cognitive phenotypic assessment. Around 150,000 currently have genetic data. We examined 111,739 participants with complete genetic and cognitive data. baseline cognitive data relating to information processing speed, memory and reasoning were used. We tested for interactions with age and with the presence versus absence of type 2 diabetes (T2D), coronary artery disease (CAD) and hypertension. in several instances, APOE e4 dosage interacted with older age and disease presence to affect cognitive scores. When adjusted for potentially confounding variables, there was no APOE e4 effect on the outcome variables. future research in large independent cohorts should continue to investigate this important question, which has potential implications for aetiology related to dementia and cognitive impairment. © The Author 2016. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Apolipoprotein E4 reduces evoked hippocampal acetylcholine release in adult mice.

PubMed

Dolejší, Eva; Liraz, Ori; Rudajev, Vladimír; Zimčík, Pavel; Doležal, Vladimír; Michaelson, Daniel M

2016-02-01

Apolipoprotein E4 (apoE4) is the most prevalent genetic risk factor for Alzheimer's disease. We utilized apoE4-targeted replacement mice (approved by the Tel Aviv University Animal Care Committee) to investigate whether cholinergic dysfunction, which increases during aging and is a hallmark of Alzheimer's disease, is accentuated by apoE4. This revealed that levels of the pre-synaptic cholinergic marker, vesicular acetylcholine transporter in the hippocampus and the corresponding electrically evoked release of acetylcholine, are similar in 4-month-old apoE4 and apolipoprotein E3 (apoE3) mice. Both parameters decrease with age. This decrease is, however, significantly more pronounced in the apoE4 mice. The levels of cholinacetyltransferase (ChAT), acetylcholinesterase (AChE), and butyrylcholinesterase (BuChE) were similar in the hippocampus of young apoE4 and apoE3 mice and decreased during aging. For ChAT, this decrease was similar in the apoE4 and apoE3 mice, whereas it was more pronounced in the apoE4 mice, regarding their corresponding AChE and BuChE levels. The level of muscarinic receptors was higher in the apoE4 than in the apoE3 mice at 4 months and increased to similar levels with age. However, the relative representation of the M1 receptor subtype decreased during aging in apoE4 mice. These results demonstrate impairment of the evoked release of acetylcholine in hippocampus by apoE4 in 12-month-old mice but not in 4-month-old mice. The levels of ChAT and the extent of the M2 receptor-mediated autoregulation of ACh release were similar in the adult mice, suggesting that the apoE4-related inhibition of hippocampal ACh release in these mice is not driven by these parameters. Evoked ACh release from hippocampal and cortical slices is similar in 4-month-old apoE4 and apoE3 mice but is specifically and significantly reduced in hippocampus, but not cortex, of 12-month-old apoE4 mice. This effect is accompanied by decreased VAChT levels. These findings show that

A critical role for transcription factor Smad4 in T cell function that is independent of transforming growth factor β receptor signaling.

PubMed

Gu, Ai-Di; Zhang, Song; Wang, Yunqi; Xiong, Hui; Curtis, Thomas A; Wan, Yisong Y

2015-01-20

Transforming growth factor-beta (TGF-β) suppresses T cell function to maintain self-tolerance and to promote tumor immune evasion. Yet how Smad4, a transcription factor component of TGF-β signaling, regulates T cell function remains unclear. Here we have demonstrated an essential role for Smad4 in promoting T cell function during autoimmunity and anti-tumor immunity. Smad4 deletion rescued the lethal autoimmunity resulting from transforming growth factor-beta receptor (TGF-βR) deletion and compromised T-cell-mediated tumor rejection. Although Smad4 was dispensable for T cell generation, homeostasis, and effector function, it was essential for T cell proliferation after activation in vitro and in vivo. The transcription factor Myc was identified to mediate Smad4-controlled T cell proliferation. This study thus reveals a requirement of Smad4 for T-cell-mediated autoimmunity and tumor rejection, which is beyond the current paradigm. It highlights a TGF-βR-independent role for Smad4 in promoting T cell function, autoimmunity, and anti-tumor immunity. Copyright © 2015 Elsevier Inc. All rights reserved.

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

The impact on quality of life on families of children on an elimination diet for Non-immunoglobulin E mediated gastrointestinal food allergies.

PubMed

Meyer, Rosan; Godwin, Heather; Dziubak, Robert; Panepinto, Julie A; Foong, Ru-Xin M; Bryon, Mandy; Lozinsky, Adriana Chebar; Reeve, Kate; Shah, Neil

2017-01-01

The impact on health related quality of life (HRQL) has been well studied in children with Immunoglobulin E (IgE)-mediated food allergy. However limited data exists on related quality of life (QOL) of families who have a child suffering from food protein induced non-IgE mediated gastrointestinal allergies. We aimed to establish the QOL of families with children at the beginning of following an elimination diet for non-IgE mediated gastrointestinal food allergies. A prospective, observational study was performed. Parents of children aged 4 weeks-16 years who improved after 4-8 weeks of following an elimination diet for suspected non-IgE mediated allergies were included. The Family Impact Module (FIM) of the Pediatric Quality of Life (PedsQL™) was used and we compared our data to two historical cohorts: one with sickle cell disease and another with intestinal failure. One hundred and twenty three children with a median age of 20 months were included (84 boys). The total FIM Score was 57.43 (SD 22.27) and particularly low for daily activities and worry. Factors that impacted significantly included age ( p  < 0.0001), number of foods excluded ( p  = 0.008), symptom severity ( p  = 0.041) and chronic nasal congestion ( p  = 0.012). Children with non-IgE mediated food allergies had worse scores in all domains ( p  < 0.0001) compared to sickle cell disease and worse physical ( p  = 0.04), emotional ( p  = 0.04) and worry ( p  = 0.01) domains compared to intestinal failure. This study found that parent QOL and family functioning was worse in those families who had a child on an elimination diet for non-IgE mediated allergies compared to those with sickle cell disease and intestinal failure, highlighting the impact this disease has on families.

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

Adenovirus Protein E4-ORF1 Activation of PI3 Kinase Reveals Differential Regulation of Downstream Effector Pathways in Adipocytes.

PubMed

Chaudhary, Natasha; Gonzalez, Eva; Chang, Sung-Hee; Geng, Fuqiang; Rafii, Shahin; Altorki, Nasser K; McGraw, Timothy E

2016-12-20

Insulin activation of phosphatidylinositol 3-kinase (PI3K) regulates metabolism, including the translocation of the Glut4 glucose transporter to the plasma membrane and inactivation of the FoxO1 transcription factor. Adenoviral protein E4-ORF1 stimulates cellular glucose metabolism by mimicking growth-factor activation of PI3K. We have used E4-ORF1 as a tool to dissect PI3K-mediated signaling in adipocytes. E4-ORF1 activation of PI3K in adipocytes recapitulates insulin regulation of FoxO1 but not regulation of Glut4. This uncoupling of PI3K effects occurs despite E4-ORF1 activating PI3K and downstream signaling to levels achieved by insulin. Although E4-ORF1 does not fully recapitulate insulin's effects on Glut4, it enhances insulin-stimulated insertion of Glut4-containing vesicles to the plasma membrane independent of Rab10, a key regulator of Glut4 trafficking. E4-ORF1 also stimulates plasma membrane translocation of ubiquitously expressed Glut1 glucose transporter, an effect that is likely essential for E4-ORF1 to promote an anabolic metabolism in a broad range of cell types. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

Induction of cyclooxygenase-2 expression by prostaglandin E2 stimulation of the prostanoid EP4 receptor via coupling to Gαi and transactivation of the epidermal growth factor receptor in HCA-7 human colon cancer cells.

PubMed

Yoshida, Kenji; Fujino, Hiromichi; Otake, Sho; Seira, Naofumi; Regan, John W; Murayama, Toshihiko

2013-10-15

Increased expressions of cyclooxygenase-2 (COX-2) and its downstream metabolite, prostaglandin E2 (PGE2), are well documented events in the development of colorectal cancer. Interestingly, PGE2 itself can induce the expression of COX-2 thereby creating the potential for positive feedback. Although evidence for such a positive feedback has been previously described, the specific E-type prostanoid (EP) receptor subtype that mediates this response, as well as the relevant signaling pathways, remain unclear. We now report that the PGE2 stimulated induction of COX-2 expression in human colon cancer HCA-7 cells is mediated by activation of the prostanoid EP4 receptor subtype and is followed by coupling of the receptor to Gαi and the activation of phosphatidylinositol 3-kinase. Subsequent activation of metalloproteinases releases membrane bound heparin-binding epidermal growth factor-like growth factor resulting in the transactivation of epidermal growth factor receptors and the activation of the extracellular signal-regulated kinases and induction of COX-2 expression. This induction of COX-2 expression by PGE2 stimulation of the prostanoid EP4 receptor may underlie the upregulation of COX-2 during colorectal cancer and appears to be an early event in the process of tumorigenesis. © 2013 Elsevier B.V. All rights reserved.

Antiallergic effect of fisetin on IgE-mediated mast cell activation in vitro and on passive cutaneous anaphylaxis (PCA).

PubMed

Jo, Woo-Ri; Park, Hye-Jin

2017-10-01

Fisetin (3,7,3',4'-tetrahydroxyflavone), a naturally occurring bioactive flavonoid, has been shown to inhibit inflammation. However, little is known about the effect of fisetin on immunoglobulin E (IgE)-mediated allergic responses. In this study, the effect of fisetin on rat basophilic leukemia (RBL-2H3) cell-mediated allergic reactions was investigated. Fisetin inhibited β-hexosaminidase release and decreased the level of interleukin-4 and tumor necrosis factor-α mRNA in IgE/antigen (IgE/Ag)-stimulated RBL-2H3 cells. To elucidate the antiallergic mechanism, we examined the levels of signaling molecules responsible for degranulation and release of inflammatory cytokines. Fisetin decreased the levels of activated spleen tyrosine kinase, Gab2 proteins, linker of activated T cells, extracellular signal-related kinase 1/2 in the IgE/Ag-stimulated RBL2H3 cells, and NFκB and STAT3 proteins activated in the ear tissue of mice with passive cutaneous anaphylaxis (PCA). In addition, fisetin significantly lowered of FcɛRI α-subunit mRNA expression. Consistent with the cellular data, fisetin markedly suppressed RBL-2H3 cell-dependent PCA in IgE/Ag-sensitized mice. These results suggest that fisetin may have potential as a therapeutic agent for the treatment of allergic diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

Association between IgE-mediated allergies and diabetes mellitus type 1 in children and adolescents.

PubMed

Klamt, Sabine; Vogel, Mandy; Kapellen, Thomas M; Hiemisch, Andreas; Prenzel, Freerk; Zachariae, Silke; Ceglarek, Uta; Thiery, Joachim; Kiess, Wieland

2015-11-01

Type 1 diabetes mellitus (T1DM) is characterized by an immunological reaction that is dominated by type-1 T helper (Th1) cells, whereas immunoglobulin E (IgE)-mediated allergies are associated with Th2 cell. According to the Th1/Th2-hypothesis, the immune system is said to either develop into the direction of Th1 or Th2 cells. This would mean that a child developing T1DM is unlikely to develop an IgE-mediated allergy and vice versa. The aim of the study was to investigate the association between the prevalence of T1DM and IgE-mediated allergies. We designed a prospective case control study with 94 children and adolescents with T1DM and 188 age- and sex-matched control children. The basis of our investigations was a questionnaire concerning the family and children's history as to the presence of IgE-mediated allergies. Moreover, the following blood investigations were done: total serum IgE, specific IgE antibodies to major inhalant allergens, and a multiplex cytokine analysis measuring levels of specific cytokines representing either Th1- or Th2- cytokines. Children with T1DM reported the presence of IgE-mediated allergies significantly more often than children of the control group. Children with T1DM had significantly higher tumor necrosis factor alpha (TNFα) levels than healthy controls. Levels of interleukin-2 (IL-2) and IL-6 were higher in the groups of children with the presence of a personal history of allergies, regardless of the presence of T1DM. Our results suggest that T1DM is associated with a higher risk of a self-reported presence of IgE-mediated allergies and that the Th1/Th2-hypothesis may be an oversimplification. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

PRMT5 is essential for the eIF4E-mediated 5′-cap dependent translation

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

Lim, Ji-Hong; Lee, Yoon-Mi; Lee, Gibok

2014-10-03

Highlights: • PRMT5 participates in syntheses of HIF-1α, c-Myc and cyclin D1 proteins. • PRMT5 promotes the 5′-cap dependent translation. • PRMT5 is required for eIF4E binding to mRNA 5′-cap. • PRMT5 is essential for eIF4E-dependent cell proliferation. - Abstract: It is becoming clear that PRMT5 plays essential roles in cell cycle progression, survival, and responses to external stresses. However, the precise mechanisms underlying such roles of PRMT5 have not been clearly understood. Previously, we have demonstrated that PRMT5 participates in cellular adaptation to hypoxia by ensuring 5′-cap dependent translation of HIF-1α. Given that c-Myc and cyclin D1 expressions aremore » also tightly regulated in 5′-cap dependent manner, we here tested the possibility that PRMT5 promotes cell proliferation by increasing de novo syntheses of the oncoproteins. c-Myc and cyclin D1 were found to be noticeably downregulated by PRMT5 knock-down. A RNA immunoprecipitation analysis, which can identify RNA–protein interactions, showed that PRMT5 is required for the interaction among eIF4E and 5′-UTRs of HIF-1α, c-Myc and cyclin D1 mRNAs. In addition, PRMT5 knock-down inhibited cell proliferation by inducing cell cycle arrest at the G1 phase. More importantly, ectopic expression of eIF4E significantly rescued the cell cycle progression and cell proliferation even in PRMT5-deficeint condition. Based on these results, we propose that PRMT5 determines cell fate by regulating 5′-cap dependent translation of proteins essential for proliferation and survival.« less

The nuclear factor κB inhibitor (E)-2-fluoro-4′-methoxystilbene inhibits firefly luciferase

PubMed Central

Braeuning, Albert; Vetter, Silvia

2012-01-01

Photinus pyralis (firefly) luciferase is widely used as a reporter system to monitor alterations in gene promoter and/or signalling pathway activities in vitro. The enzyme catalyses the formation of oxyluciferin from D-luciferin in an ATP-consuming reaction involving photon emission. The purpose of the present study was to characterize the luciferase-inhibiting potential of (E)-2-fluoro-4′-methoxystilbene, which is known as a potent inhibitor of the NF-κB (nuclear factor κB) signalling pathway that is used to modulate the NF-κB signalling pathway in vitro. Results show that (E)-2-fluoro-4′-methoxystilbene effectively inhibits firefly luciferase activity in cell lysates and living cells in a non-competitive manner with respect to the luciferase substrates D-luciferin and ATP. By contrast, the compound has no effect on Renilla and Gaussia luciferases. The mechanism of firefly luciferase inhibition by (E)-2-fluoro-4′-methoxystilbene, as well as its potency is comparable to its structure analogue resveratrol. The in vitro use of trans-stilbenes such as (E)-2-fluoro-4′-methoxystilbene or resveratrol compromises firefly luciferase reporter assays as well as ATP/luciferase-based cell viability assays. PMID:22789175

Cooperative modulation by eIF4G of eIF4E-binding to the mRNA 5' cap in yeast involves a site partially shared by p20.

PubMed Central

Ptushkina, M; von der Haar, T; Vasilescu, S; Frank, R; Birkenhäger, R; McCarthy, J E

1998-01-01

Interaction between the mRNA 5'-cap-binding protein eIF4E and the multiadaptor protein eIF4G has been demonstrated in all eukaryotic translation assemblies examined so far. This study uses immunological, genetic and biochemical methods to map the surface amino acids on eIF4E that contribute to eIF4G binding. Cap-analogue chromatography and surface plasmon resonance (SPR) analyses demonstrate that one class of mutations in these surface regions disrupts eIF4E-eIF4G association, and thereby polysome formation and growth. The residues at these positions in wild-type eIF4E mediate positive cooperativity between the binding of eIF4G to eIF4E and the latter's cap-affinity. Moreover, two of the mutations confer temperature sensitivity in eIF4G binding to eIF4E which correlates with the formation of large numbers of inactive ribosome 80S couples in vivo and the loss of cellular protein synthesis activity. The yeast 4E-binding protein p20 is estimated by SPR to have a ten times lower binding affinity than eIF4G for eIF4E. Investigation of a second class of eIF4E mutations reveals that p20 shares only part of eIF4G's binding site on the cap-binding protein. The results presented provide a basis for understanding how cycling of eIF4E and eIF4G occurs in yeast translation and explains how p20 can act as a fine, but not as a coarse, regulator of protein synthesis. PMID:9707439

Krüppel-like factor 4, a novel transcription factor regulates microglial activation and subsequent neuroinflammation.

PubMed

Kaushik, Deepak K; Gupta, Malvika; Das, Sulagna; Basu, Anirban

2010-10-15

Activation of microglia, the resident macrophages of the central nervous system (CNS), is the hallmark of neuroinflammation in neurodegenerative diseases and other pathological conditions associated with CNS infection. The activation of microglia is often associated with bystander neuronal death. Nuclear factor-κB (NF-κB) is one of the important transcription factors known to be associated with microglial activation which upregulates the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (Cox-2) and other pro-inflammatory cytokines. Recent studies have focused on the role of Krüppel-like factor 4 (Klf4), one of the zinc-finger transcription factors, in mediating inflammation. However, these studies were limited to peripheral system and its role in CNS is not understood. Our studies focused on the possible role of Klf4 in mediating CNS inflammation. For in vitro studies, mouse microglial BV-2 cell lines were treated with 500 ng/ml Salmonella enterica lipopolysacchride (LPS). Brain tissues were isolated from BALB/c mice administered with 5 mg/kg body weight of LPS. Expressions of Klf4, Cox-2, iNOS and pNF-κB were evaluated using western blotting, quantitative real time PCR, and reverse transcriptase polymerase chain reactions (RT-PCRs). Klf4 knockdown was carried out using SiRNA specific for Klf4 mRNA and luciferase assays and electromobility shift assay (EMSA) were performed to study the interaction of Klf4 to iNOS promoter elements in vitro. Co-immunoprecipitation of Klf4 and pNF-κB was done in order to study a possible interaction between the two transcription factors. LPS stimulation increased Klf4 expression in microglial cells in a time- and dose-dependent manner. Knockdown of Klf4 resulted in decreased levels of the pro-inflammatory cytokines TNF-α, MCP-1 and IL-6, along with a significant decrease in iNOS and Cox-2 expression. NO production also decreased as a result of Klf4 knockdown. We found that Klf4 can potentially interact with

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.

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).

Prostaglandin E2 activates the mTORC1 pathway through an EP4/cAMP/PKA- and EP1/Ca2+-mediated mechanism in the human pancreatic carcinoma cell line PANC-1.

PubMed

Chang, Hui-Hua; Young, Steven H; Sinnett-Smith, James; Chou, Caroline Ei Ne; Moro, Aune; Hertzer, Kathleen M; Hines, Oscar Joe; Rozengurt, Enrique; Eibl, Guido

2015-11-15

Obesity, a known risk factor for pancreatic cancer, is associated with inflammation and insulin resistance. Proinflammatory prostaglandin E2 (PGE2) and elevated insulin-like growth factor type 1 (IGF-1), related to insulin resistance, are shown to play critical roles in pancreatic cancer progression. We aimed to explore a potential cross talk between PGE2 signaling and the IGF-1/Akt/mammalian target of rapamycin complex 1 (mTORC1) pathway in pancreatic cancer, which may be a key to unraveling the obesity-cancer link. In PANC-1 human pancreatic cancer cells, we showed that PGE2 stimulated mTORC1 activity independently of Akt, as evaluated by downstream signaling events. Subsequently, using pharmacological and genetic approaches, we demonstrated that PGE2-induced mTORC1 activation is mediated by the EP4/cAMP/PKA pathway, as well as an EP1/Ca(2+)-dependent pathway. The cooperative roles of the two pathways were supported by the maximal inhibition achieved with the combined pharmacological blockade, and the coexistence of highly expressed EP1 (mediating the Ca(2+) response) and EP2 or EP4 (mediating the cAMP/PKA pathway) in PANC-1 cells and in the prostate cancer line PC-3, which also robustly exhibited PGE2-induced mTORC1 activation, as identified from a screen in various cancer cell lines. Importantly, we showed a reinforcing interaction between PGE2 and IGF-1 on mTORC1 signaling, with an increase in IL-23 production as a cellular outcome. Our data reveal a previously unrecognized mechanism of PGE2-stimulated mTORC1 activation mediated by EP4/cAMP/PKA and EP1/Ca(2+) signaling, which may be of great importance in elucidating the promoting effects of obesity in pancreatic cancer. Ultimately, a precise understanding of these molecular links may provide novel targets for efficacious interventions devoid of adverse effects. Copyright © 2015 the American Physiological Society.

Hepatic Stellate Cells Express Functional CXCR4: Role in Stromal Cell–Derived Factor-1α–Mediated Stellate Cell Activation

PubMed Central

Hong, Feng; Tuyama, Ana; Lee, Ting Fang; Loke, Johnny; Agarwal, Ritu; Cheng, Xin; Garg, Anita; Fiel, M. Isabel; Schwartz, Myron; Walewski, Jose; Branch, Andrea; Schecter, Alison D.; Bansal, Meena B.

2010-01-01

Chemokine interactions with their receptors have been implicated in hepatic stellate cell (HSC) activation. The hepatic expression of CXCR4 messenger RNA is increased in hepatitis C cirrhotic livers and plasma levels of its endogenous ligand, stromal cell–derived factor-1α (SDF-1α), correlate with increased fibrosis in these patients. The expression of CXCR4 by HSCs has not been reported. We therefore examined whether HSCs express CXCR4 in vivo and in vitro and explored whether SDF-1α/CXCR4 receptor engagement promotes HSC activation, fibrogenesis, and proliferation. The hepatic protein expression of both CXCR4 and SDF-1α is increased in hepatitis C cirrhotic livers and immunoflourescent and immunohistochemical staining confirms that HSCs express CXCR4 in vivo. Immortalized human stellate cells as well as primary human HSCs express CXCR4, and cell surface receptor expression increases with progressive culture-induced activation. Treatment of stellate cells with recombinant SDF-1α increases expression of α-smooth muscle actin and collagen I and stimulates a dose-dependent increase in HSC proliferation. Inhibitor studies suggest that SDF-1α/CXCR4-dependent extracellular signal-regulated kinase 1/2 and Akt phosphorylation mediate effects on collagen I expression and stellate cell proliferation. Conclusion HSCs express CXCR4 receptor in vivo and in vitro. CXCR4 receptor activation by SDF-1α is profibrogenic through its effects on HSC activation, fibrogenesis, and proliferation. Extracellular signal-regulated kinase 1/2 and phosphoinositide 3-kinase pathways mediate SDF-1α–induced effects on HSC expression of collagen I and proliferation. The availability of small molecule inhibitors of CXCR4 make this receptor an appealing target for antifibrotic approaches. PMID:19434726

How do physicians discuss e-health with patients? the relationship of physicians' e-health beliefs to physician mediation styles.

PubMed

Fujioka, Yuki; Stewart, Erin

2013-01-01

A survey of 104 physicians examined the role of physicians' evaluation of the quality of e-health and beliefs about the influence of patients' use of e-health in how physicians discuss e-health materials with patients. Physicians' lower (poor) evaluation of the quality of e-health content predicted more negative mediation (counter-reinforcement of e-health content). Perceived benefits of patients' e-health use predicted more positive (endorsement of e-health content). Physician's perceived concerns (negative influence) regarding patients' e-health use were not a significant predictor for their mediation styles. Results, challenging the utility of restrictive mediation, suggested reconceptualizing it as redirective mediation in a medical interaction. The study suggested that patient-generated e-health-related inquiries invite physician mediation in medical consultations. Findings and implications are discussed in light of the literature of physician-patient interaction, incorporating the theory of parental mediation of media into a medical context.

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

Recombinant platelet factor 4: a therapeutic, anti-neoplastic chimera?

PubMed

Lippi, Giuseppe; Favaloro, Emmanuel J

2010-07-01

Angiogenesis plays a pivotal role in many serious and life-threatening disorders (e.g., cancer, atherosclerosis, diabetes, arthritis, psoriasis, nephropathy, and retinopathy) and is regulated by a delicate equilibrium between a variety of pro- and anti-angiogenic factors. Although recombinant platelet factor 4 (PF4) was originally developed and evaluated as a clinical alternative to protamine for heparin neutralization, the current scientific evidence supports a role for this protein and derivative peptides in inhibiting tumor growth and spread, by suppression of tumor-induced neovascularization in many different types of solid tumors. As a heparin-binding tetramer, recombinant PF4 interferes with several steps of endothelial cell proliferation, migration, and angiogenesis, regulates apoptotic death through activation of distinct signal transduction pathways, inhibits growth factor receptor binding, amplifies the inflammatory response of natural killer cells through regulation of cytokines production, and induces and maintains a nonspecific immune response to cancer cells. These biological evidences paved the way for the development and marketing of novel PF4-based angiostatic agents characterized by reduced toxicity and improved bioavailability, thus raising the possibility of an alternative approach for preventing and treating growth and metastasis of tumors. Some PF4-derived molecules such as carboxyl-terminal fragments of recombinant human PF4 and modified and chimeric peptides have already been developed that exhibit stronger anti-angiogenic properties than the parent molecule and may serve as leads for further therapeutic developments. Newer means of delivering of this anti-angiogenic agent are also being attempted, including PF4-bearing polymeric microspheres, vector-mediated PF4 transduction, transgene transfection into oncolytic viruses, and molecular targeting therapy against PF4 and rHuPF4 conjugates. These delivery systems aim to produce high

Antisense oligonucleotide–mediated MDM4 exon 6 skipping impairs tumor growth

PubMed Central

Dewaele, Michael; Tabaglio, Tommaso; Willekens, Karen; Bezzi, Marco; Teo, Shun Xie; Low, Diana H.P.; Koh, Cheryl M.; Rambow, Florian; Fiers, Mark; Rogiers, Aljosja; Radaelli, Enrico; Al-Haddawi, Muthafar; Tan, Soo Yong; Hermans, Els; Amant, Frederic; Yan, Hualong; Lakshmanan, Manikandan; Koumar, Ratnacaram Chandrahas; Lim, Soon Thye; Derheimer, Frederick A.; Campbell, Robert M.; Bonday, Zahid; Tergaonkar, Vinay; Shackleton, Mark; Blattner, Christine; Marine, Jean-Christophe; Guccione, Ernesto

2015-01-01

MDM4 is a promising target for cancer therapy, as it is undetectable in most normal adult tissues but often upregulated in cancer cells to dampen p53 tumor-suppressor function. The mechanisms that underlie MDM4 upregulation in cancer cells are largely unknown. Here, we have shown that this key oncogenic event mainly depends on a specific alternative splicing switch. We determined that while a nonsense-mediated, decay-targeted isoform of MDM4 (MDM4-S) is produced in normal adult tissues as a result of exon 6 skipping, enhanced exon 6 inclusion leads to expression of full-length MDM4 in a large number of human cancers. Although this alternative splicing event is likely regulated by multiple splicing factors, we identified the SRSF3 oncoprotein as a key enhancer of exon 6 inclusion. In multiple human melanoma cell lines and in melanoma patient–derived xenograft (PDX) mouse models, antisense oligonucleotide–mediated (ASO-mediated) skipping of exon 6 decreased MDM4 abundance, inhibited melanoma growth, and enhanced sensitivity to MAPK-targeting therapeutics. Additionally, ASO-based MDM4 targeting reduced diffuse large B cell lymphoma PDX growth. As full-length MDM4 is enhanced in multiple human tumors, our data indicate that this strategy is applicable to a wide range of tumor types. We conclude that enhanced MDM4 exon 6 inclusion is a common oncogenic event and has potential as a clinically compatible therapeutic target. PMID:26595814

Cryptochrome 1 interacts with PIF4 to regulate high temperature-mediated hypocotyl elongation in response to blue light.

PubMed

Ma, Dingbang; Li, Xu; Guo, Yongxia; Chu, Jingfang; Fang, Shuang; Yan, Cunyu; Noel, Joseph P; Liu, Hongtao

2016-01-05

Cryptochrome 1 (CRY1) is a blue light receptor that mediates primarily blue-light inhibition of hypocotyl elongation. Very little is known of the mechanisms by which CRY1 affects growth. Blue light and temperature are two key environmental signals that profoundly affect plant growth and development, but how these two abiotic factors integrate remains largely unknown. Here, we show that blue light represses high temperature-mediated hypocotyl elongation via CRY1. Furthermore, CRY1 interacts directly with PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) in a blue light-dependent manner to repress the transcription activity of PIF4. CRY1 represses auxin biosynthesis in response to elevated temperature through PIF4. Our results indicate that CRY1 signal by modulating PIF4 activity, and that multiple plant photoreceptors [CRY1 and PHYTOCHROME B (PHYB)] and ambient temperature can mediate morphological responses through the same signaling component-PIF4.

Cryptochrome 1 interacts with PIF4 to regulate high temperature-mediated hypocotyl elongation in response to blue light

PubMed Central

Ma, Dingbang; Li, Xu; Guo, Yongxia; Chu, Jingfang; Fang, Shuang; Yan, Cunyu; Noel, Joseph P.; Liu, Hongtao

2016-01-01

Cryptochrome 1 (CRY1) is a blue light receptor that mediates primarily blue-light inhibition of hypocotyl elongation. Very little is known of the mechanisms by which CRY1 affects growth. Blue light and temperature are two key environmental signals that profoundly affect plant growth and development, but how these two abiotic factors integrate remains largely unknown. Here, we show that blue light represses high temperature-mediated hypocotyl elongation via CRY1. Furthermore, CRY1 interacts directly with PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) in a blue light-dependent manner to repress the transcription activity of PIF4. CRY1 represses auxin biosynthesis in response to elevated temperature through PIF4. Our results indicate that CRY1 signal by modulating PIF4 activity, and that multiple plant photoreceptors [CRY1 and PHYTOCHROME B (PHYB)] and ambient temperature can mediate morphological responses through the same signaling component—PIF4. PMID:26699514

Transcription factor FBI-1 acts as a dual regulator in adipogenesis by coordinated regulation of cyclin-A and E2F-4.

PubMed

Laudes, Matthias; Bilkovski, Roman; Oberhauser, Frank; Droste, Andrea; Gomolka, Matthias; Leeser, Uschi; Udelhoven, Michael; Krone, Wilhelm

2008-05-01

Generation of new adipocytes plays a major role in the development of obesity. We previously have shown that transcriptional repressor factor that binds to IST (FBI)-1 exerts a dual effect in the process of adipogenesis by inhibiting proliferation and promoting differentiation of preadipocytes. The aim of the present study was to identify FBI-1 regulated molecular effectors that could account for these effects. Overexpressing FBI-1 in preadipocytes resulted in reduced expression of the cell cycle regulator cyclin A, which may explain FBI-1 induced inhibition of proliferation. Interestingly, FBI-1 repressed cyclin A promoter activity through an indirect mechanisms that did not involve direct binding of FBI-1 to the promoter sequence, but rather FBI-1 inhibition of transcriptional activator Sp1 binding to a regulatory element at -452 to -443. We also show that FBI-1 promotes terminal preadipocyte differentiation through a mechanism involving decreased levels of expression of the PPARgamma inhibitor E2F-4. FBI-1 significantly reduced E2F-4 promoter activity. Contrary to cyclin A, we found FBI-1-induced repression of E2F-4 is mediated by a direct mechanism via a FBI-1 regulatory element at -11 to -5. As function of transcriptional repressors normally depends on the presence of regulatory co-factors we also performed expression profiling of potential FBI-1 co-repressors throughout adipogenesis. In these experiments Sin3A and histon deacetylase (HDAC)-1 showed a similar expression pattern compared to FBI-1. Strikingly, co-immunoprecipitation studies revealed that FBI-1 binds Sin3A and HDAC-1 to form a repressor complex. Furthermore, by mutational analysis the amino terminal Poxvirus (POZ) domain of FBI-1 was found to be important for Sin3A and HDAC-1 binding. Taken together, FBI-1 is the first transcriptional repressor shown to act as a dual regulator in adipogenesis exerting repressor activities on target genes by both, direct and indirect mechanisms.

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

Angiostatic and chemotactic activities of the CXC chemokine CXCL4L1 (platelet factor-4 variant) are mediated by CXCR3

PubMed Central

Struyf, Sofie; Salogni, Laura; Burdick, Marie D.; Vandercappellen, Jo; Gouwy, Mieke; Noppen, Sam; Proost, Paul; Opdenakker, Ghislain; Parmentier, Marc; Gerard, Craig; Sozzani, Silvano; Strieter, Robert M.

2011-01-01

We investigated possible cellular receptors for the human CXC chemokine platelet factor-4 variant/CXCL4L1, a potent inhibitor of angiogenesis. We found that CXCL4L1 has lower affinity for heparin and chondroitin sulfate-E than platelet factor-4 (CXCL4) and showed that CXCL10 and CXCL4L1 could displace each other on microvascular endothelial cells. Labeled CXCL4L1 also bound to CXCR3A- and CXCR3B-transfectants and was displaced by CXCL4L1, CXCL4, and CXCL10. The CXCL4L1 anti-angiogenic activity was blocked by anti-CXCR3 antibodies (Abs) in the Matrigel and cornea micropocket assays. CXCL4L1 application in CXCR3−/− or in wild-type mice treated with neutralizing anti-CXCR3 Abs, resulted in reduced inhibitory activity of CXCL4L1 on tumor growth and vascularization of Lewis lung carcinoma. Furthermore, CXCL4L1 and CXCL4 chemoattracted activated T cells, human natural killer cells, and human immature dendritic cells (DCs). Migration of DCs toward CXCL4 and CXCL4L1 was desensitized by preincubation with CXCL10 and CXCL11, inhibited by pertussis toxin, and neutralized by anti-CXCR3 Abs. Chemotaxis of T cells, natural killer cells, and DCs is likely to contribute to the antitumoral action. However, the in vivo data indicate that the angiostatic property of CXCL4L1 is equally important in retarding tumor growth. Thus, both CXCR3A and CXCR3B are implicated in the chemotactic and vascular effects of CXCL4L1. PMID:20980681

Angiostatic and chemotactic activities of the CXC chemokine CXCL4L1 (platelet factor-4 variant) are mediated by CXCR3.

PubMed

Struyf, Sofie; Salogni, Laura; Burdick, Marie D; Vandercappellen, Jo; Gouwy, Mieke; Noppen, Sam; Proost, Paul; Opdenakker, Ghislain; Parmentier, Marc; Gerard, Craig; Sozzani, Silvano; Strieter, Robert M; Van Damme, Jo

2011-01-13

We investigated possible cellular receptors for the human CXC chemokine platelet factor-4 variant/CXCL4L1, a potent inhibitor of angiogenesis. We found that CXCL4L1 has lower affinity for heparin and chondroitin sulfate-E than platelet factor-4 (CXCL4) and showed that CXCL10 and CXCL4L1 could displace each other on microvascular endothelial cells. Labeled CXCL4L1 also bound to CXCR3A- and CXCR3B-transfectants and was displaced by CXCL4L1, CXCL4, and CXCL10. The CXCL4L1 anti-angiogenic activity was blocked by anti-CXCR3 antibodies (Abs) in the Matrigel and cornea micropocket assays. CXCL4L1 application in CXCR3(-/-) or in wild-type mice treated with neutralizing anti-CXCR3 Abs, resulted in reduced inhibitory activity of CXCL4L1 on tumor growth and vascularization of Lewis lung carcinoma. Furthermore, CXCL4L1 and CXCL4 chemoattracted activated T cells, human natural killer cells, and human immature dendritic cells (DCs). Migration of DCs toward CXCL4 and CXCL4L1 was desensitized by preincubation with CXCL10 and CXCL11, inhibited by pertussis toxin, and neutralized by anti-CXCR3 Abs. Chemotaxis of T cells, natural killer cells, and DCs is likely to contribute to the antitumoral action. However, the in vivo data indicate that the angiostatic property of CXCL4L1 is equally important in retarding tumor growth. Thus, both CXCR3A and CXCR3B are implicated in the chemotactic and vascular effects of CXCL4L1.

Grb2 mediates semaphorin-4D-dependent RhoA inactivation.

PubMed

Sun, Tianliang; Krishnan, Rameshkumar; Swiercz, Jakub M

2012-08-01

Signaling through the semaphorin 4D (Sema4D) receptor plexin-B1 is modulated by its interaction with tyrosine kinases ErbB-2 and Met. In cells expressing the plexin-B1-ErbB-2 receptor complex, ligand stimulation results in the activation of small GTPase RhoA and stimulation of cellular migration. By contrast, in cells expressing plexin-B1 and Met, ligand stimulation results in an association with the RhoGTPase-activating protein p190 RhoGAP and subsequent RhoA inactivation--a process that involves the tyrosine phosphorylation of plexin-B1 by Met. Inactivation of RhoA is necessary for Sema4D-mediated inhibition of cellular migration. It is, however, unknown how plexin-B1 phosphorylation regulates RhoGAP interaction and activity. Here we show that the activation of plexin-B1 by Sema4D and its subsequent tyrosine phosphorylation by Met creates a docking site for the SH2 domain of growth factor receptor bound-2 (Grb2). Grb2 is thereby recruited into the plexin-B1 receptor complex and, through its SH3 domain, interacts with p190 RhoGAP and mediates RhoA deactivation. Phosphorylation of plexin-B1 by Met and the recruitment of Grb2 have no effect on the R-RasGAP activity of plexin-B1, but are required for Sema4D-induced, RhoA-dependent antimigratory effects of Sema4D on breast cancer cells. These data show Grb2 as a direct link between plexin and p190-RhoGAP-mediated downstream signaling.

Ligand-mediated protein degradation reveals functional conservation among sequence variants of the CUL4-type E3 ligase substrate receptor cereblon.

PubMed

Akuffo, Afua A; Alontaga, Aileen Y; Metcalf, Rainer; Beatty, Matthew S; Becker, Andreas; McDaniel, Jessica M; Hesterberg, Rebecca S; Goodheart, William E; Gunawan, Steven; Ayaz, Muhammad; Yang, Yan; Karim, Md Rezaul; Orobello, Morgan E; Daniel, Kenyon; Guida, Wayne; Yoder, Jeffrey A; Rajadhyaksha, Anjali M; Schönbrunn, Ernst; Lawrence, Harshani R; Lawrence, Nicholas J; Epling-Burnette, Pearlie K

2018-04-20

Upon binding to thalidomide and other immunomodulatory drugs, the E3 ligase substrate receptor cereblon (CRBN) promotes proteosomal destruction by engaging the DDB1-CUL4A-Roc1-RBX1 E3 ubiquitin ligase in human cells but not in mouse cells, suggesting that sequence variations in CRBN may cause its inactivation. Therapeutically, CRBN engagers have the potential for broad applications in cancer and immune therapy by specifically reducing protein expression through targeted ubiquitin-mediated degradation. To examine the effects of defined sequence changes on CRBN's activity, we performed a comprehensive study using complementary theoretical, biophysical, and biological assays aimed at understanding CRBN's nonprimate sequence variations. With a series of recombinant thalidomide-binding domain (TBD) proteins, we show that CRBN sequence variants retain their drug-binding properties to both classical immunomodulatory drugs and dBET1, a chemical compound and targeting ligand designed to degrade bromodomain-containing 4 (BRD4) via a CRBN-dependent mechanism. We further show that dBET1 stimulates CRBN's E3 ubiquitin-conjugating function and degrades BRD4 in both mouse and human cells. This insight paves the way for studies of CRBN-dependent proteasome-targeting molecules in nonprimate models and provides a new understanding of CRBN's substrate-recruiting function. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

F4+ enterotoxigenic Escherichia coli (ETEC) adhesion mediated by the major fimbrial subunit FaeG.

PubMed

Xia, Pengpeng; Song, Yujie; Zou, Yajie; Yang, Ying; Zhu, Guoqiang

2015-09-01

The FaeG subunit is the major constituent of F4(+) fimbriae, associated with glycoprotein and/or glycolipid receptor recognition and majorly contributes to the pathogen attachment to the host cells. To investigate the key factor involved in the fimbrial binding of F4(+) Escherichia coli, both the recombinant E. coli SE5000 strains carrying the fae operon gene clusters that express the different types of fimbriae in vitro, named as rF4ab, rF4ac, and rF4ad, respectively, corresponding to the fimbrial types F4ab, F4ac, and F4ad, and the three isogenic in-frame faeG gene deletion mutants were constructed. The adhesion assays and adhesion inhibition assays showed that ΔfaeG mutants had a significant reduction in the binding to porcine brush border as well as the intestinal epithelial cell lines, while the complemented strain ΔfaeG/pfaeG restored the adhesion function. The recombinant bacterial strains rF4ab, rF4ac, and rF4ad have the same binding property as wild-type F4(+) E. coli strains do and improvement in terms of binding to porcine brush border and the intestinal epithelial cells, and the adherence was blocked by the monoclonal antibody anti-F4 fimbriae. These data demonstrate that the fimbrial binding of F4(+) E. coli is directly mediated by the major FaeG subunit. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Mediation Analysis Demonstrates That Trans-eQTLs Are Often Explained by Cis-Mediation: A Genome-Wide Analysis among 1,800 South Asians

PubMed Central

Pierce, Brandon L.; Tong, Lin; Chen, Lin S.; Rahaman, Ronald; Argos, Maria; Jasmine, Farzana; Roy, Shantanu; Paul-Brutus, Rachelle; Westra, Harm-Jan; Franke, Lude; Esko, Tonu; Zaman, Rakibuz; Islam, Tariqul; Rahman, Mahfuzar; Baron, John A.; Kibriya, Muhammad G.; Ahsan, Habibul

2014-01-01

A large fraction of human genes are regulated by genetic variation near the transcribed sequence (cis-eQTL, expression quantitative trait locus), and many cis-eQTLs have implications for human disease. Less is known regarding the effects of genetic variation on expression of distant genes (trans-eQTLs) and their biological mechanisms. In this work, we use genome-wide data on SNPs and array-based expression measures from mononuclear cells obtained from a population-based cohort of 1,799 Bangladeshi individuals to characterize cis- and trans-eQTLs and determine if observed trans-eQTL associations are mediated by expression of transcripts in cis with the SNPs showing trans-association, using Sobel tests of mediation. We observed 434 independent trans-eQTL associations at a false-discovery rate of 0.05, and 189 of these trans-eQTLs were also cis-eQTLs (enrichment P<0.0001). Among these 189 trans-eQTL associations, 39 were significantly attenuated after adjusting for a cis-mediator based on Sobel P<10-5. We attempted to replicate 21 of these mediation signals in two European cohorts, and while only 7 trans-eQTL associations were present in one or both cohorts, 6 showed evidence of cis-mediation. Analyses of simulated data show that complete mediation will be observed as partial mediation in the presence of mediator measurement error or imperfect LD between measured and causal variants. Our data demonstrates that trans-associations can become significantly stronger or switch directions after adjusting for a potential mediator. Using simulated data, we demonstrate that this phenomenon is expected in the presence of strong cis-trans confounding and when the measured cis-transcript is correlated with the true (unmeasured) mediator. In conclusion, by applying mediation analysis to eQTL data, we show that a substantial fraction of observed trans-eQTL associations can be explained by cis-mediation. Future studies should focus on understanding the mechanisms underlying

Effect of glucocorticosteroid treatment on ovalbumin-induced IgE-mediated immediate and late allergic response in guinea pig.

PubMed

Andersson, P; Brange, C; von Kogerer, B; Sonmark, B; Stahre, G

1988-01-01

The effect of glucocorticosteroid (GCS) treatment on ovalbumine-induced IgE-mediated immediate and late allergic response was studied in sensitized guinea pigs. The results show that the GCS budesonide (BUD) inhibits the allergen-induced IgE-mediated immediate and late bronchial obstruction. The effect on the early reaction is correlated to the inhibition of leukotrienes and histamine release. The importance of mediator release inhibition for the antianaphylactic effect of GCS is discussed. In examining the effect on the late reaction, it was found that BUD had to be present during the early reaction but did not inhibit the early reaction. Furthermore, the effect on the late reaction was correlated to the inhibition of vascular leakage but not to the infiltration of inflammatory cells as examined in bronchoalveolar lavage. The results indicate that some triggering factors important for the development of the late reaction are released during the early reaction. Inhibition of the release of that factor or the activation of inflammatory cells by that factor might be the mechanism behind the antiinflammatory activities of GCS.

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.

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.

17beta-estradiol promotes breast cancer cell proliferation-inducing stromal cell-derived factor-1-mediated epidermal growth factor receptor transactivation: reversal by gefitinib pretreatment.

PubMed

Pattarozzi, Alessandra; Gatti, Monica; Barbieri, Federica; Würth, Roberto; Porcile, Carola; Lunardi, Gianluigi; Ratto, Alessandra; Favoni, Roberto; Bajetto, Adriana; Ferrari, Angelo; Florio, Tullio

2008-01-01

The coordinated activity of estrogens and epidermal growth factor receptor (EGFR) family agonists represents the main determinant of breast cancer cell proliferation. Stromal cell-derived factor-1 (SDF-1) enhances extracellular signal-regulated kinases 1 and 2 (ERK1/2) activity via the transactivation of EGFR and 17beta-estradiol (E2) induces SDF-1 production to exert autocrine proliferative effects. On this basis, we evaluated whether the inhibition of the tyrosine kinase (TK) activity of EGFR may control different mitogenic stimuli in breast tumors using the EGFR-TK inhibitor gefitinib to antagonize the proliferation induced by E2 in T47D human breast cancer cells. EGF, E2, and SDF-1 induced a dose-dependent T47D cell proliferation, that being nonadditive suggested the activation of common intracellular pathways. Gefitinib treatment inhibited not only the EGF-dependent proliferation and ERK1/2 activation but also the effects of SDF-1 and E2, suggesting that these activities were mediated by EGFR transactivation. Indeed, both SDF-1 and E2 caused EGFR tyrosine phosphorylation. The molecular link between E2 and SDF-1 proliferative effects was identified because 1,1'-(1,4-phenylenebis(methylene))-bis-1,4,8,11-tetraazacyclotetradecane octahydrochloride (AMD3100), a CXCR4 antagonist, inhibited SDF-1- and E2-dependent proliferation and EGFR and ERK1/2 phosphorylation. EGFR transactivation was dependent on c-Src activation. E2 treatment caused a powerful SDF-1 release from T47D cells. Finally, in SKBR3, E2-resistant cells, EGFR was constitutively activated, and AMD3100 reduced EGFR phosphorylation and cell proliferation, whereas HER2-neu was transactivated by SDF-1 in SKBR3 but not in T47D cells. In conclusion, we show that activation of CXCR4 transduces proliferative signals from the E2 receptor to EGFR, whose inhibition is able to revert breast cancer cell proliferation induced by multiple receptor activation.

Nuclear factor E2-related factor-2 has a differential impact on MCT1 and MCT4 lactate carrier expression in colonic epithelial cells: a condition favoring metabolic symbiosis between colorectal cancer and stromal cells.

PubMed

Diehl, K; Dinges, L-A; Helm, O; Ammar, N; Plundrich, D; Arlt, A; Röcken, C; Sebens, S; Schäfer, H

2018-01-04

Malignant tumors, such as colorectal cancer (CRC), are heterogeneous diseases characterized by distinct metabolic phenotypes. These include Warburg- and reverse Warburg phenotypes depending on differential distribution of the lactate carrier proteins monocarboxylate transporter-4 and -1 (MCT4 and MCT1). Here, we elucidated the role of the antioxidant transcription factor nuclear factor E2-related factor-2 (Nrf2) as the key regulator of cellular adaptation to inflammatory/environmental stress in shaping the metabolism toward a reverse Warburg phenotype in malignant and premalignant colonic epithelial cells. Immunohistochemistry of human CRC tissues revealed reciprocal expression of MCT1 and MCT4 in carcinoma and stroma cells, respectively, accompanied by strong epithelial Nrf2 activation. In colorectal tissue from inflammatory bowel disease patients, MCT1 and Nrf2 were coexpressed as well, relating to CD68+inflammatory infiltrates. Indirect coculture of human NCM460 colonocytes with M1- but not M2 macrophages induces MCT1 as well as G6PD, LDHB and TALDO expression, whereas MCT4 expression was decreased. Nrf2 knockdown or reactive oxygen species (ROS) scavenging blocked these coculture effects in NCM460 cells. Likewise, Nrf2 knockdown inhibited similar effects of tBHQ-mediated Nrf2 activation on NCM460 and HCT15 CRC cells. M1 coculture or Nrf2 activation/overexpression greatly altered the lactate uptake but not glucose uptake and mitochondrial activities in these cells, reflecting the reverse Warburg phenotype. Depending on MCT1-mediated lactate uptake, Nrf2 conferred protection from TRAIL-induced apoptosis in NCM460 and HCT15 cells. Moreover, metabolism-dependent clonal growth of HCT15 cells was induced by Nrf2-dependent activation of MCT1-driven lactate exchange. These findings indicate that Nrf2 has an impact on the metabolism already in premalignant colonic epithelial cells exposed to inflammatory M1 macrophages, an effect accompanied by growth and survival

Genomic and transcriptomic comparison of allergen and silver nanoparticle-induced mast cell degranulation reveals novel non-immunoglobulin E mediated mechanisms.

PubMed

Johnson, Monica; Alsaleh, Nasser; Mendoza, Ryan P; Persaud, Indushekhar; Bauer, Alison K; Saba, Laura; Brown, Jared M

2018-01-01

Mast cells represent a crucial cell type in host defense; however, maladaptive responses are contributing factors in the pathogenesis of allergic diseases. Previous work in our laboratory has shown that exposure to silver nanoparticles (AgNPs) results in mast cell degranulation via a non-immunoglobulin E (IgE) mechanism. In this study, we utilized a systems biology approach to identify novel genetic factors playing a role in AgNP-induced mast cell degranulation compared to the classical activation by antigen-mediated FcεRI crosslinking. Mast cell degranulation was assessed in bone marrow-derived mast cells isolated from 23 strains of mice following exposure to AgNPs or FcεRI crosslinking with dinitrophenyl (DNP). Utilizing strain-dependent mast cell degranulation, an association mapping study identified 3 chromosomal regions that were significantly associated with mast cell degranulation by AgNP and one non-overlapping region associated with DNP-mediated degranulation. Two of the AgNP-associated regions correspond to genes previously reported to be associated with allergic disorders (Trac2 on chromosome 1 and Traf6 on chromosome 2) and an uncharacterized gene identified on chromosome 1 (Fam126b). In conjunction, RNA-sequencing performed on mast cells from the high and low responder strains revealed 3754 and 34 differentially expressed genes that were unique to DNP and AgNP exposures, respectively. Select candidate genes include Ptger4, a gene encoding a G-protein coupled receptor in addition to a multifunctional adaptor protein, Txnip, that may be driving mast cell degranulation by AgNP. Taken together, we identified novel genes that have not been previously shown to play a role in nanoparticle-mediated mast cell activation. With further functional evaluation in the future, these genes may be potential therapeutic targets in the treatment of non-IgE mediated mast cell-linked disorders.

ApoE4 expression accelerates hippocampus-dependent cognitive deficits by enhancing Aβ impairment of insulin signaling in an Alzheimer’s disease mouse model

PubMed Central

Chan, Elizabeth S.; Shetty, Mahesh Shivarama; Sajikumar, Sreedharan; Chen, Christopher; Soong, Tuck Wah; Wong, Boon-Seng

2016-01-01

The apolipoprotein E4 (ApoE4) is the strongest genetic risk factor for Alzheimer’s disease (AD). The AD brain was shown to be insulin resistant at end stage, but the interplay between insulin signaling, ApoE4 and Aβ across time, and their involvement in memory decline is unclear. To investigate insulin response in the ageing mouse hippocampus, we crossed the human ApoE-targeted replacement mice with the mutant human amyloid precursor protein (APP) mice (ApoExAPP). While hippocampal Aβ levels were comparable between ApoE3xAPP and ApoE4xAPP mice at 26 weeks, insulin response was impaired in the ApoE4xAPP hippocampus. Insulin treatment was only able to stimulate insulin signaling and increased AMPA-GluR1 phosphorylation in forskolin pre-treated hippocampal slices from ApoE3xAPP mice. In ApoE4xAPP mice, insulin dysfunction was also associated with poorer spatial memory performance. Using dissociated hippocampal neuron in vitro, we showed that insulin response in ApoE3 and ApoE4 neurons increased AMPA receptor-mediated miniature excitatory postsynaptic current (mEPSC) amplitudes and GluR1-subunit insertion. Pre-treatment of ApoE3 neurons with Aβ42 did not affect insulin-mediated GluR1 subunit insertion. However, impaired insulin sensitivity observed only in the presence of ApoE4 and Aβ42, attenuated GluR1-subunit insertion. Taken together, our results suggest that ApoE4 enhances Aβ inhibition of insulin-stimulated AMPA receptor function, which accelerates memory impairment in ApoE4xAPP mice. PMID:27189808

eIF4B stimulates translation of long mRNAs with structured 5′ UTRs and low closed-loop potential but weak dependence on eIF4G

PubMed Central

Sen, Neelam Dabas; Zhou, Fujun; Harris, Michael S.; Ingolia, Nicholas T.

2016-01-01

DEAD-box RNA helicases eukaryotic translation initiation factor 4A (eIF4A) and Ded1 promote translation by resolving mRNA secondary structures that impede preinitiation complex (PIC) attachment to mRNA or scanning. Eukaryotic translation initiation factor 4B (eIF4B) is a cofactor for eIF4A but also might function independently of eIF4A. Ribosome profiling of mutants lacking eIF4B or with impaired eIF4A or Ded1 activity revealed that eliminating eIF4B reduces the relative translational efficiencies of many more genes than does inactivation of eIF4A, despite comparable reductions in bulk translation, and few genes display unusually strong requirements for both factors. However, either eliminating eIF4B or inactivating eIF4A preferentially impacts mRNAs with longer, more structured 5′ untranslated regions (UTRs). These findings reveal an eIF4A-independent role for eIF4B in addition to its function as eIF4A cofactor in promoting PIC attachment or scanning on structured mRNAs. eIF4B, eIF4A, and Ded1 mutations also preferentially impair translation of longer mRNAs in a fashion mitigated by the ability to form closed-loop messenger ribonucleoprotein particles (mRNPs) via eIF4F–poly(A)-binding protein 1 (Pab1) association, suggesting cooperation between closed-loop assembly and eIF4B/helicase functions. Remarkably, depleting eukaryotic translation initiation factor 4G (eIF4G), the scaffold subunit of eukaryotic translation initiation factor 4F (eIF4F), preferentially impacts short mRNAs with strong closed-loop potential and unstructured 5′ UTRs, exactly the opposite features associated with hyperdependence on the eIF4B/helicases. We propose that short, highly efficient mRNAs preferentially depend on the stimulatory effects of eIF4G-dependent closed-loop assembly. PMID:27601676

Apolipoprotein E4 Allele and Gait Performance in Mild Cognitive Impairment: Results From the Gait and Brain Study.

PubMed

Sakurai, Ryota; Montero-Odasso, Manuel

2017-11-09

The apolipoprotein E polymorphism ε4 allele (ApoE4) and gait impairment are both known risk factors for developing cognitive decline and dementia. However, it is unclear the interrelationship between these factors, particularly among older adults with mild cognitive impairment (MCI) who are considered as prodromal for Alzheimer's disease. This study aimed to determine whether ApoE4 carrier individuals with MCI may experience greater impairment in gait performance. Fifty-six older adults with MCI from the "Gait and Brain Study" who were identified as either ApoE4 carriers (n = 20) or non-ApoE4 carriers (n = 36) with 1 year of follow-up were included. Gait variability, the main outcome variable, was assessed as stride time variability with an electronic walkway. Additional gait variables and cognitive performance (mini-mental state examination [MMSE] and Montreal Cognitive Assessment [MoCA]) were also recorded. Covariates included age, sex, education level, body mass index, and number of comorbidities. Baseline characteristics were similar for both groups. Repeated measures analysis of covariance showed that gait stride time and stride length variabilities significantly increased in ApoE4 carriers but was maintained in the non-ApoE4 carriers. Similarly, ApoE4 carriers showed greater decrease in MMSE score at follow-up. In this sample of older adults with MCI, the presence of at least one copy of ApoE4 was associated with the development of both increased gait variability and cognitive decline during 1 year of follow-up. ApoE4 genotype might be considered as a potential mediator of decline in mobility function in MCI; future studies with larger samples are needed to confirm our preliminary findings. © The Author 2017. 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.

GATA4-mediated cardiac hypertrophy induced by D-myo-inositol 1,4,5-tris-phosphate

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

Zhu Zhiming; Zhu Shanjun; Liu Daoyan

2005-12-16

We evaluated the effects of D-myo-inositol 1,4,5-tris-phosphate on cardiac hypertrophy. D-myo-inositol 1,4,5-tris-phosphate augmented cardiac hypertrophy as evidenced by its effects on DNA synthesis, protein synthesis, and expression of immediate-early genes c-myc and c-fos, {beta}-myosin heavy chain, and {alpha}-actin. The administration of D-myo-inositol 1,4,5-tris-phosphate increased the expression of nuclear factor of activated T-cells and cardiac-restricted zinc finger transcription factor (GATA4). Real-time quantitative RT-PCR showed that D-myo-inositol 1,4,5-tris-phosphate-induced GATA4 mRNA was significantly enhanced even in the presence of the calcineurin inhibitor, cyclosporine A. The effect of D-myo-inositol 1,4,5-tris-phosphate was blocked after inhibition of inositol-trisphosphate receptors but not after inhibition of c-Raf/mitogen-activated proteinmore » kinase kinase (MEK)/mitogen-activated protein kinase (ERK) or p38 mitogen-activated protein kinase pathways. The study shows that D-myo-inositol 1,4,5-tris-phosphate-induced cardiac hypertrophy is mediated by GATA4 but independent from the calcineurin pathway.« less

Cardiac tissue enriched factors serum response factor and GATA-4 are mutual coregulators

NASA Technical Reports Server (NTRS)

Belaguli, N. S.; Sepulveda, J. L.; Nigam, V.; Charron, F.; Nemer, M.; Schwartz, R. J.

2000-01-01

Combinatorial interaction among cardiac tissue-restricted enriched transcription factors may facilitate the expression of cardiac tissue-restricted genes. Here we show that the MADS box factor serum response factor (SRF) cooperates with the zinc finger protein GATA-4 to synergistically activate numerous myogenic and nonmyogenic serum response element (SRE)-dependent promoters in CV1 fibroblasts. In the absence of GATA binding sites, synergistic activation depends on binding of SRF to the proximal CArG box sequence in the cardiac and skeletal alpha-actin promoter. GATA-4's C-terminal activation domain is obligatory for synergistic coactivation with SRF, and its N-terminal domain and first zinc finger are inhibitory. SRF and GATA-4 physically associate both in vivo and in vitro through their MADS box and the second zinc finger domains as determined by protein A pullout assays and by in vivo one-hybrid transfection assays using Gal4 fusion proteins. Other cardiovascular tissue-restricted GATA factors, such as GATA-5 and GATA-6, were equivalent to GATA-4 in coactivating SRE-dependent targets. Thus, interaction between the MADS box and C4 zinc finger proteins, a novel regulatory paradigm, mediates activation of SRF-dependent gene expression.

Do Sleep and Psychological Distress Mediate the Association Between Neighborhood Factors and Pain?

PubMed

Brooks Holliday, Stephanie; Dubowitz, Tamara; Ghosh-Dastidar, Bonnie; Beckman, Robin; Buysse, Daniel; Hale, Lauren; Buman, Matthew; Troxel, Wendy

2018-05-14

Pain affects millions of American adults. However, individuals from socioeconomically disadvantaged groups experience higher rates of pain, and individuals from racial/ethnic minorities report greater pain severity and pain-related disability. Some studies find an association between neighborhood socioeconomic status and pain. The present study aimed to further understand the association between neighborhood disadvantage and pain, including the role of objective (e.g., crime rates) and subjective neighborhood characteristics (e.g., perceived safety, neighborhood satisfaction), and to examine sleep and psychological distress as potential mediators of these associations. The sample included 820 participants from two predominantly African American socioeconomically disadvantaged neighborhoods. Trained data collectors interviewed participants on a number of self-report measures, and objective neighborhood characteristics were obtained from city crime data and street segment audits. Subjective characteristics, specifically perceived infrastructure and perceived safety, were associated with pain. Based on bootstrapped regression models, sleep efficiency and psychological distress were tested as mediators of the association between these neighborhood factors and pain. Results of mediation testing indicated that psychological distress served as a significant mediator. Though sleep efficiency was not a mediator, it had a significant independent association with pain. Understanding the contribution of sleep problems and psychological distress to pain among at-risk individuals living in disadvantaged neighborhoods is important to identifying ways that individual- and neighborhood-level interventions may be leveraged to reduce pain-related disparities.

Early age of e-cigarette use onset mediates the association between impulsivity and e-cigarette use frequency in youth.

PubMed

Bold, Krysten W; Morean, Meghan E; Kong, Grace; Simon, Patricia; Camenga, Deepa R; Cavallo, Dana A; Krishnan-Sarin, Suchitra

2017-12-01

Identifying risk factors for youth e-cigarette use is critical, given high rates of e-cigarette use and unknown health effects of long-term use. The current study examined whether an early age of onset of e-cigarette use mediates the association between impulsivity and e-cigarette frequency. Cross-sectional survey data of e-cigarette users (n=927) were collected from 8 high schools in southeastern Connecticut. The sample was 44.7% female (mean age 16.2 [SD=1.2], mean age of e-cigarette onset 14.7 [SD=1.6]). Two domains of self-reported, trait impulsivity were assessed using the abbreviated Barratt Impulsiveness Scale: impaired self-regulation (e.g., problems with concentration or self-control) and behavioral impulsivity (e.g., doing things without thinking). Mediation was tested with Mplus, and the model included school as a cluster variable and controlled for covariates related to e-cigarette use (i.e., sex, age, race, peer use, and other tobacco products ever tried). The hypothesized mediation was supported for both domains of impulsivity (impaired self-regulation a 1 b=0.09, SE=0.02, 95%CI [0.03-0.14], p=.002; behavioral impulsivity a 2 b=0.07, SE=0.03, 95%CI [.01-.14], p=0.03). Specifically, impaired self-regulation (B=-0.33, SE=0.06, p<0.001) and behavioral impulsivity (B=-0.26, SE=0.11, p=0.02) predicted trying e-cigarettes at an earlier age, and earlier initiation was associated with more days of e-cigarette use in the past month (B=-0.28, SE=0.08, p<0.001). Adolescents who endorse aspects of impulsivity, such as acting without thinking, are at greater risk for more frequent e-cigarette use through an early age of e-cigarette initiation. Further research is needed to evaluate these relationships longitudinally and to develop targeted e-cigarette interventions for impulsive youth. Copyright © 2017 Elsevier B.V. All rights reserved.

IgE-mediated food allergies in Swiss infants and children.

PubMed

Ferrari, Giovanni Gaspare; Eng, Peter Andreas

2011-10-12

To determine the most frequent food allergens causing immediate hypersensitivity reactions in Swiss children of different age groups and to investigate the clinical manifestation of IgE-mediated food allergies in young patients. The study was a prospective analysis of children referred for assessment of immediate type I food hypersensitivity reactions. The diagnostic strategy included a careful history, skin prick tests with commercial extracts and native foods, in vitro determination of specific IgE to food proteins and food challenges when appropriate. A total of 278 food allergies were identified in 151 children with a median age of 1.9 years at diagnosis. Overall, the most frequent food allergens were hen's egg (23.7%), cow's milk (20.1%), peanut (14.0%), hazelnut (10.4%), wheat (6.1%), fish (4.3%), kiwi and soy (2.2% each). In infancy, cow's milk, hen's egg and wheat were the most common allergens. In the second and third year of life however, the top three food allergens were hen's egg, cow's milk and peanut, whereas above the age of 3 years, peanut was number one, followed by hen's egg and fish. Overall, urticaria (59.0%) and angioedema (30.2%) were the most frequent clinical manifestations. Gastrointestinal symptoms were found in 25.9% and respiratory involvement in 25.2%. There were 13 cases (4.7%) of anaphylaxis to peanut, fish, cow's milk, hen's egg, wheat and shrimps. A total of eight allergens account for 83% of IgE-mediated food allergies in Swiss infants and children, with differences in the distribution and order of the most frequently involved food allergens between paediatric age groups.

Cytotoxic-T-lymphocyte antigen 4 receptor signaling for lymphocyte adhesion is mediated by C3G and Rap1.

PubMed

Kloog, Yoel; Mor, Adam

2014-03-01

T-lymphocyte adhesion plays a critical role in both inflammatory and autoimmune responses. The small GTPase Rap1 is the key coordinator mediating T-cell adhesion to endothelial cells, antigen-presenting cells, and virus-infected cells. We describe a signaling pathway, downstream of the cytotoxic T-lymphocyte antigen 4 (CTLA-4) receptor, leading to Rap1-mediated adhesion. We identified a role for the Rap1 guanine nucleotide exchange factor C3G in the regulation of T-cell adhesion and showed that this factor is required for both T-cell receptor (TCR)-mediated and CTLA-4-mediated T-cell adhesion. Our data indicated that C3G translocates to the plasma membrane downstream of TCR signaling, where it regulates activation of Rap1. We also showed that CTLA-4 receptor signaling mediates tyrosine phosphorylation in the C3G protein, and that this is required for augmented activation of Rap1 and increased adhesion mediated by leukocyte function-associated antigen type 1 (LFA-1). Zap70 is required for C3G translocation to the plasma membrane, whereas the Src family member Hck facilitates C3G phosphorylation. These findings point to C3G and Hck as promising potential therapeutic targets for the treatment of T-cell-dependent autoimmune disorders.

Cytotoxic-T-Lymphocyte Antigen 4 Receptor Signaling for Lymphocyte Adhesion Is Mediated by C3G and Rap1

PubMed Central

Kloog, Yoel

2014-01-01

T-lymphocyte adhesion plays a critical role in both inflammatory and autoimmune responses. The small GTPase Rap1 is the key coordinator mediating T-cell adhesion to endothelial cells, antigen-presenting cells, and virus-infected cells. We describe a signaling pathway, downstream of the cytotoxic T-lymphocyte antigen 4 (CTLA-4) receptor, leading to Rap1-mediated adhesion. We identified a role for the Rap1 guanine nucleotide exchange factor C3G in the regulation of T-cell adhesion and showed that this factor is required for both T-cell receptor (TCR)-mediated and CTLA-4-mediated T-cell adhesion. Our data indicated that C3G translocates to the plasma membrane downstream of TCR signaling, where it regulates activation of Rap1. We also showed that CTLA-4 receptor signaling mediates tyrosine phosphorylation in the C3G protein, and that this is required for augmented activation of Rap1 and increased adhesion mediated by leukocyte function-associated antigen type 1 (LFA-1). Zap70 is required for C3G translocation to the plasma membrane, whereas the Src family member Hck facilitates C3G phosphorylation. These findings point to C3G and Hck as promising potential therapeutic targets for the treatment of T-cell-dependent autoimmune disorders. PMID:24396067

Distinct Akt phosphorylation states are required for insulin regulated Glut4 and Glut1-mediated glucose uptake.

PubMed

Beg, Muheeb; Abdullah, Nazish; Thowfeik, Fathima Shazna; Altorki, Nasser K; McGraw, Timothy E

2017-06-07

Insulin, downstream of Akt activation, promotes glucose uptake into fat and muscle cells to lower postprandial blood glucose, an enforced change in cellular metabolism to maintain glucose homeostasis. This effect is mediated by the Glut4 glucose transporter. Growth factors also enhance glucose uptake to fuel an anabolic metabolism required for tissue growth and repair. This activity is predominantly mediated by the Glut1. Akt is activated by phosphorylation of its kinase and hydrophobic motif (HM) domains. We show that insulin-stimulated Glut4-mediated glucose uptake requires PDPK1 phosphorylation of the kinase domain but not mTORC2 phosphorylation of the HM domain. Nonetheless, an intact HM domain is required for Glut4-mediated glucose uptake. Whereas, Glut1-mediated glucose uptake also requires mTORC2 phosphorylation of the HM domain, demonstrating both phosphorylation-dependent and independent roles of the HM domain in regulating glucose uptake. Thus, mTORC2 links Akt to the distinct physiologic programs related to Glut4 and Glut1-mediated glucose uptake.

Citrus peel polymethoxyflavones nobiletin and tangeretin suppress LPS- and IgE-mediated activation of human intestinal mast cells.

PubMed

Hagenlocher, Yvonne; Feilhauer, Katharina; Schäffer, Michael; Bischoff, Stephan C; Lorentz, Axel

2017-06-01

Allergic diseases with mast cells (MC) as main effector cells show an increased prevalence. MC also play an essential role in other inflammatory conditions. Therapeutical use of anti-inflammatory nutraceuticals directly targeting MC activation could be of interest for afflicted patients. Nobiletin and tangeretin are citrus peel polymethoxyflavones, a group of citrus flavonoids, possessing anticancer, antimetastatic, and anti-inflammatory activities. Here, we analyzed the effects of nobiletin/tangeretin on LPS- and IgE-mediated stimulation of human intestinal mast cells (hiMC). MC isolated from human intestinal tissue were treated with different concentrations of nobiletin or tangeretin prior to stimulation via LPS/sCD14 or IgE-dependently. Degranulation, pro-inflammatory cytokine expression and phosphorylation of ERK1/2 were examined. Expression of CXCL8, CCL3, CCL4 and IL-1β in response to LPS-mediated stimulation was inhibited by nobiletin/tangeretin. hiMC activated IgE-dependently showed a reduced release of β-hexosaminidase and cysteinyl LTC 4 in response to nobiletin, but not in response to tangeretin. Expression of CXCL8, CCL2, CCL3, CCL4 and TNF in IgE-dependently activated hiMC was decreased in a dose-dependent manner following treatment with nobiletin/tangeretin. IL-1β expression was only reduced by tangeretin. Compared to treatment with NF-κB inhibitor BMS345541 or MEK-inhibitor PD98059, nobiletin and tangeretin showed similar effects on mediator production. Phosphorylation of ERK1/2 upon IgE-mediated antigen stimulation was significantly suppressed by nobiletin and tangeretin. Nobiletin and, to a lesser extent, tangeretin could be considered as anti-inflammatory nutraceuticals by reducing release and production of proinflammatory mediators in MC.

E2F1-mediated upregulation of p19INK4d determines its periodic expression during cell cycle and regulates cellular proliferation.

PubMed

Carcagno, Abel L; Marazita, Mariela C; Ogara, María F; Ceruti, Julieta M; Sonzogni, Silvina V; Scassa, María E; Giono, Luciana E; Cánepa, Eduardo T

2011-01-01

A central aspect of development and disease is the control of cell proliferation through regulation of the mitotic cycle. Cell cycle progression and directionality requires an appropriate balance of positive and negative regulators whose expression must fluctuate in a coordinated manner. p19INK4d, a member of the INK4 family of CDK inhibitors, has a unique feature that distinguishes it from the remaining INK4 and makes it a likely candidate for contributing to the directionality of the cell cycle. p19INK4d mRNA and protein levels accumulate periodically during the cell cycle under normal conditions, a feature reminiscent of cyclins. In this paper, we demonstrate that p19INK4d is transcriptionally regulated by E2F1 through two response elements present in the p19INK4d promoter. Ablation of this regulation reduced p19 levels and restricted its expression during the cell cycle, reflecting the contribution of a transcriptional effect of E2F1 on p19 periodicity. The induction of p19INK4d is delayed during the cell cycle compared to that of cyclin E, temporally separating the induction of these proliferative and antiproliferative target genes. Specific inhibition of the E2F1-p19INK4d pathway using triplex-forming oligonucleotides that block E2F1 binding on p19 promoter, stimulated cell proliferation and increased the fraction of cells in S phase. The results described here support a model of normal cell cycle progression in which, following phosphorylation of pRb, free E2F induces cyclin E, among other target genes. Once cyclinE/CDK2 takes over as the cell cycle driving kinase activity, the induction of p19 mediated by E2F1 leads to inhibition of the CDK4,6-containing complexes, bringing the G1 phase to an end. This regulatory mechanism constitutes a new negative feedback loop that terminates the G1 phase proliferative signal, contributing to the proper coordination of the cell cycle and provides an additional mechanism to limit E2F activity.

E2F1-Mediated Upregulation of p19INK4d Determines Its Periodic Expression during Cell Cycle and Regulates Cellular Proliferation

PubMed Central

Carcagno, Abel L.; Marazita, Mariela C.; Ogara, María F.; Ceruti, Julieta M.; Sonzogni, Silvina V.; Scassa, María E.; Giono, Luciana E.; Cánepa, Eduardo T.

2011-01-01

Background A central aspect of development and disease is the control of cell proliferation through regulation of the mitotic cycle. Cell cycle progression and directionality requires an appropriate balance of positive and negative regulators whose expression must fluctuate in a coordinated manner. p19INK4d, a member of the INK4 family of CDK inhibitors, has a unique feature that distinguishes it from the remaining INK4 and makes it a likely candidate for contributing to the directionality of the cell cycle. p19INK4d mRNA and protein levels accumulate periodically during the cell cycle under normal conditions, a feature reminiscent of cyclins. Methodology/Principal Findings In this paper, we demonstrate that p19INK4d is transcriptionally regulated by E2F1 through two response elements present in the p19INK4d promoter. Ablation of this regulation reduced p19 levels and restricted its expression during the cell cycle, reflecting the contribution of a transcriptional effect of E2F1 on p19 periodicity. The induction of p19INK4d is delayed during the cell cycle compared to that of cyclin E, temporally separating the induction of these proliferative and antiproliferative target genes. Specific inhibition of the E2F1-p19INK4d pathway using triplex-forming oligonucleotides that block E2F1 binding on p19 promoter, stimulated cell proliferation and increased the fraction of cells in S phase. Conclusions/Significance The results described here support a model of normal cell cycle progression in which, following phosphorylation of pRb, free E2F induces cyclin E, among other target genes. Once cyclinE/CDK2 takes over as the cell cycle driving kinase activity, the induction of p19 mediated by E2F1 leads to inhibition of the CDK4,6-containing complexes, bringing the G1 phase to an end. This regulatory mechanism constitutes a new negative feedback loop that terminates the G1 phase proliferative signal, contributing to the proper coordination of the cell cycle and provides an

The cellular Mre11 protein interferes with adenovirus E4 mutant DNA replication.

PubMed

Mathew, Shomita S; Bridge, Eileen

2007-09-01

Adenovirus type 5 (Ad5) relocalizes and degrades the host DNA repair protein Mre11, and efficiently initiates viral DNA replication. Mre11 associates with Ad E4 mutant DNA replication centers and is important for concatenating viral genomes. We have investigated the role of Mre11 in the E4 mutant DNA replication defect. RNAi-mediated knockdown of Mre11 dramatically rescues E4 mutant DNA replication in cells that do or do not concatenate viral genomes, suggesting that Mre11 inhibits DNA replication independent of genome concatenation. The mediator of DNA damage checkpoint 1 (Mdc1) protein is involved in recruiting and sustaining Mre11 at sites of DNA damage following ionizing radiation. We observe foci formation by Mdc1 in response to viral infection, indicating that this damage response protein is activated. However, knockdown of Mdc1 does not prevent Mre11 from localizing at viral DNA replication foci or rescue E4 mutant DNA replication. Our results are consistent with a model in which Mre11 interferes with DNA replication when it is localized at viral DNA replication foci.

Is Apolipoprotein E4 an Important Risk Factor for Dementia in Persons with Down Syndrome?

PubMed

Rohn, Troy T; McCarty, Katie L; Love, Julia E; Head, Elizabeth

2014-12-08

Down syndrome is one of the most common genetic causes of intellectual disability and is characterized by a number of behavioral as well as cognitive symptoms. Triplication of all or part of human chromosome 21 has been considered as the main cause of Down syndrome. Due to the location of the amyloid precursor protein on chromosome 21, many of the neuropathological features of early-onset Alzheimer's disease including senile plaques and neurofibrillary tangles are also present in Down syndrome patients who are either demented or nondemented. Significant advances in medical treatment have increased longevity in people with Down syndrome resulting in an increased population that may be subjected to many of the same risk factors as those with Alzheimer's disease. It is well established that harboring one or both apolipoprotein E4 alleles greatly increases the risk for Alzheimer's disease. However, whether apolipoprotein E4 contributes to an earlier onset of dementia or increased mortality in Down syndrome patients is still a matter of debate. The purpose of this mini review is to provide an updated assessment on apolipoprotein E4 status and risk potential of developing dementia and mortality associated with Down syndrome.

Components of the CCR4-NOT complex function as nuclear hormone receptor coactivators via association with the NRC-interacting Factor NIF-1.

PubMed

Garapaty, Shivani; Mahajan, Muktar A; Samuels, Herbert H

2008-03-14

CCR4-NOT is an evolutionarily conserved, multicomponent complex known to be involved in transcription as well as mRNA degradation. Various subunits (e.g. CNOT1 and CNOT7/CAF1) have been reported to be involved in influencing nuclear hormone receptor activities. Here, we show that CCR4/CNOT6 and RCD1/CNOT9, members of the CCR4-NOT complex, potentiate nuclear receptor activity. RCD1 interacts in vivo and in vitro with NIF-1 (NRC-interacting factor), a previously characterized nuclear receptor cotransducer that activates nuclear receptors via its interaction with NRC. As with NIF-1, RCD1 and CCR4 do not directly associate with nuclear receptors; however, they enhance ligand-dependent transcriptional activation by nuclear hormone receptors. CCR4 mediates its effect through the ligand binding domain of nuclear receptors and small interference RNA-mediated silencing of endogenous CCR4 results in a marked decrease in nuclear receptor activation. Furthermore, knockdown of CCR4 results in an attenuated stimulation of RARalpha target genes (e.g. Sox9 and HoxA1) as shown by quantitative PCR assays. The silencing of endogenous NIF-1 also resulted in a comparable decrease in the RAR-mediated induction of both Sox9 and HoxA1. Furthermore, CCR4 associates in vivo with NIF-1. In addition, the CCR4-enhanced transcriptional activation by nuclear receptors is dependent on NIF-1. The small interference RNA-mediated knockdown of NIF-1 blocks the ligand-dependent potentiating effect of CCR4. Our results suggest that CCR4 plays a role in the regulation of certain endogenous RARalpha target genes and that RCD1 and CCR4 might mediate their function through their interaction with NIF-1.

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

The role of LANP and ataxin 1 in E4F-mediated transcriptional repression

PubMed Central

Cvetanovic, Marija; Rooney, Robert J; Garcia, Jesus J; Toporovskaya, Nataliya; Zoghbi, Huda Y; Opal, Puneet

2007-01-01

The leucine-rich acidic nuclear protein (LANP) belongs to the INHAT family of corepressors that inhibits histone acetyltransferases. The mechanism by which LANP restricts its repression to specific genes is unknown. Here, we report that LANP forms a complex with transcriptional repressor E4F and modulates its activity. As LANP interacts with ataxin 1—a protein mutated in the neurodegenerative disease spinocerebellar ataxia type 1 (SCA1)—we tested whether ataxin 1 can alter the E4F–LANP interaction. We show that ataxin 1 relieves the transcriptional repression induced by the LANP–E4F complex by competing with E4F for LANP. These results provide the first functional link, to our knowledge, between LANP and ataxin 1, and indicate a potential mechanism for the transcriptional aberrations observed in SCA1. PMID:17557114

Ribosomal elongation factor 4 promotes cell death associated with lethal stress.

PubMed

Li, Liping; Hong, Yuzhi; Luan, Gan; Mosel, Michael; Malik, Muhammad; Drlica, Karl; Zhao, Xilin

2014-12-09

Ribosomal elongation factor 4 (EF4) is highly conserved among bacteria, mitochondria, and chloroplasts. However, the EF4-encoding gene, lepA, is nonessential and its deficiency shows no growth or fitness defect. In purified systems, EF4 back-translocates stalled, posttranslational ribosomes for efficient protein synthesis; consequently, EF4 has a protective role during moderate stress. We were surprised to find that EF4 also has a detrimental role during severe stress: deletion of lepA increased Escherichia coli survival following treatment with several antimicrobials. EF4 contributed to stress-mediated lethality through reactive oxygen species (ROS) because (i) the protective effect of a ΔlepA mutation against lethal antimicrobials was eliminated by anaerobic growth or by agents that block hydroxyl radical accumulation and (ii) the ΔlepA mutation decreased ROS levels stimulated by antimicrobial stress. Epistasis experiments showed that EF4 functions in the same genetic pathway as the MazF toxin, a stress response factor implicated in ROS-mediated cell death. The detrimental action of EF4 required transfer-messenger RNA (tmRNA, which tags truncated proteins for degradation and is known to be inhibited by EF4) and the ClpP protease. Inhibition of a protective, tmRNA/ClpP-mediated degradative activity would allow truncated proteins to indirectly perturb the respiratory chain and thereby provide a potential link between EF4 and ROS. The connection among EF4, MazF, tmRNA, and ROS expands a pathway leading from harsh stress to bacterial self-destruction. The destructive aspect of EF4 plus the protective properties described previously make EF4 a bifunctional factor in a stress response that promotes survival or death, depending on the severity of stress. Translation elongation factor 4 (EF4) is one of the most conserved proteins in nature, but it is dispensable. Lack of strong phenotypes for its genetic knockout has made EF4 an enigma. Recent biochemical work has

Differences in problem behaviour among ethnic minority and majority preschoolers in the Netherlands and the role of family functioning and parenting factors as mediators: the Generation R Study.

PubMed

Flink, Ilse J E; Jansen, Pauline W; Beirens, Tinneke M J; Tiemeier, Henning; van IJzendoorn, Marinus H; Jaddoe, Vincent W V; Hofman, Albert; Raat, Hein

2012-12-19

Studies have shown that, compared to native counterparts, preschoolers from ethnic minorities are at an increased risk of problem behaviour. Socio-economic factors only partly explain this increased risk. This study aimed to further unravel the differences in problem behaviour among ethnic minority and native preschoolers by examining the mediating role of family functioning and parenting factors. We included 4,282 preschoolers participating in the Generation R Study, an ethnically-diverse cohort study with inclusion in early pregnancy. At child age 3 years, parents completed the Child Behavior Checklist (CBCL/1,5-5); information on demographics, socio-economic status and measures of family functioning (maternal psychopathology; general family functioning) and parenting (parenting stress; harsh parenting) were retrieved from questionnaires. CBCL Total Problems scores in each ethnic subgroup were compared with scores in the Dutch reference population. Mediation was evaluated using multivariate regression models. After adjustment for confounders, preschoolers from ethnic minorities were more likely to present problem behaviour than the Dutch subgroup (e.g. CBCL Total Problems Turkish subgroup (OR 7.0 (95% CI 4.9; 10.1)). When considering generational status, children of first generation immigrants were worse off than the second generation (P<0.01). Adjustment for socio-economic factors mediated the association between the ethnic minority status and child problem behaviour (e.g. attenuation in OR by 54.4% (P<0.05) from OR 5.1 (95% CI 2.8; 9.4) to OR 2.9 (95% CI 1.5; 5.6) in Cape Verdean subgroup). However, associations remained significant in most ethnic subgroups. A final adjustment for family functioning and parenting factors further attenuated the association (e.g. attenuation in OR by 55.5% (P<0.05) from OR 2.2 (95% CI 1.3; 4.4) to OR 1.5 (95% CI 1.0; 2.4) in European other subgroup). This study showed that preschoolers from ethnic minorities and particularly

miR-34a mediates oxaliplatin resistance of colorectal cancer cells by inhibiting macroautophagy via transforming growth factor-β/Smad4 pathway.

PubMed

Sun, Chen; Wang, Fu-Jing; Zhang, Hao-Gang; Xu, Xun-Zheng; Jia, Rui-Chun; Yao, Lei; Qiao, Peng-Fei

2017-03-14

To investigate whether microRNA (miR)-34a mediates oxaliplatin (OXA) resistance of colorectal cancer (CRC) cells by inhibiting macroautophagy via the transforming growth factor (TGF)-β/Smad4 pathway. miR-34a expression levels were detected in CRC tissues and CRC cell lines by quantitative real-time polymerase chain reaction. Computational search, functional luciferase assay and western blotting were used to demonstrate the downstream target of miR-34a in CRC cells. Cell viability was measured with Cell Counting Kit-8. Apoptosis and macroautophagy of CRC cells were analyzed by flow cytometry and transmission electron microscopy, and expression of beclin I and LC3-II was detected by western blotting. Expression of miR-34a was significantly reduced while expression of TGF-β and Smad4 was increased in CRC patients treated with OXA-based chemotherapy. OXA treatment also resulted in decreased miR-34a levels and increased TGF-β and Smad4 levels in both parental cells and the OXA-resistant CRC cells. Activation of macroautophagy contributed to OXA resistance in CRC cells. Expression levels of Smad4 and miR-34a in CRC patients had a significant inverse correlation and overexpressing miR-34a inhibited macroautophagy activation by directly targeting Smad4 through the TGF-β/Smad4 pathway. OXA-induced downregulation of miR-34a and increased drug resistance by activating macroautophagy in CRC cells. miR-34a mediates OXA resistance of CRC by inhibiting macroautophagy via the TGF-β/Smad4 pathway.

miR-34a mediates oxaliplatin resistance of colorectal cancer cells by inhibiting macroautophagy via transforming growth factor-β/Smad4 pathway

PubMed Central

Sun, Chen; Wang, Fu-Jing; Zhang, Hao-Gang; Xu, Xun-Zheng; Jia, Rui-Chun; Yao, Lei; Qiao, Peng-Fei

2017-01-01

AIM To investigate whether microRNA (miR)-34a mediates oxaliplatin (OXA) resistance of colorectal cancer (CRC) cells by inhibiting macroautophagy via the transforming growth factor (TGF)-β/Smad4 pathway. METHODS miR-34a expression levels were detected in CRC tissues and CRC cell lines by quantitative real-time polymerase chain reaction. Computational search, functional luciferase assay and western blotting were used to demonstrate the downstream target of miR-34a in CRC cells. Cell viability was measured with Cell Counting Kit-8. Apoptosis and macroautophagy of CRC cells were analyzed by flow cytometry and transmission electron microscopy, and expression of beclin I and LC3-II was detected by western blotting. RESULTS Expression of miR-34a was significantly reduced while expression of TGF-β and Smad4 was increased in CRC patients treated with OXA-based chemotherapy. OXA treatment also resulted in decreased miR-34a levels and increased TGF-β and Smad4 levels in both parental cells and the OXA-resistant CRC cells. Activation of macroautophagy contributed to OXA resistance in CRC cells. Expression levels of Smad4 and miR-34a in CRC patients had a significant inverse correlation and overexpressing miR-34a inhibited macroautophagy activation by directly targeting Smad4 through the TGF-β/Smad4 pathway. OXA-induced downregulation of miR-34a and increased drug resistance by activating macroautophagy in CRC cells. CONCLUSION miR-34a mediates OXA resistance of CRC by inhibiting macroautophagy via the TGF-β/Smad4 pathway. PMID:28348487

ROLES OF EPIDERMAL GROWTH FACTOR (EGF) AND TRANSFORMING GROWTH FACTOR-ALPHA (TGF-A) IN MEDIATION OF DIOXIN (TCDD)-INDUCED DELAYS IN DEVELOPMENT OF THE MOUSE MAMMARY GLAND

EPA Science Inventory

Roles of Epidermal Growth Factor (EGF) and Transforming Growth Factor-alpha (TGF-a) in Mediation of Dioxin (TCDD)-Induced Delays in Development of the Mouse Mammary Gland.
Suzanne E. Fenton, Barbara Abbott, Lamont Bryant, and Angela Buckalew. U.S. EPA, NHEERL, Reproductive Tox...

Expression of Shiga toxin 2e glycosphingolipid receptors of primary porcine brain endothelial cells and toxin-mediated breakdown of the blood-brain barrier.

PubMed

Meisen, Iris; Rosenbrück, Regina; Galla, Hans-Joachim; Hüwel, Sabine; Kouzel, Ivan U; Mormann, Michael; Karch, Helge; Müthing, Johannes

2013-06-01

Shiga toxin (Stx) 2e, released by certain Stx-producing Escherichia coli, is presently the best characterized virulence factor responsible for pig edema disease, which is characterized by hemorrhagic lesions, neurological disorders and often fatal outcomes. Although Stx2e-mediated brain vascular injury is the key event in development of neurologic signs, the glycosphingolipid (GSL) receptors of Stx2e and toxin-mediated impairment of pig brain endothelial cells have not been investigated so far. Here, we report on the detailed structural characterization of Stx2e receptors globotriaosylceramide (Gb3Cer) and globotetraosylceramide (Gb4Cer), which make up the major neutral GSLs in primary porcine brain capillary endothelial cells (PBCECs). Various Gb3Cer and Gb4Cer lipoforms harboring sphingenine (d18:1) or sphinganine (d18:0) and mostly a long-chain fatty acid (C20-C24) were detected. A notable batch-to-batch heterogeneity of primary endothelial cells was observed regarding the extent of ceramide hydroxylation of Gb3Cer or Gb4Cer species. Gb3Cer, Gb4Cer and sphingomyelin preferentially distribute to detergent-resistant membrane fractions and can be considered lipid raft markers in PBCECs. Moreover, we employed an in vitro model of the blood-brain barrier (BBB), which exhibited strong cytotoxic effects of Stx2e on the endothelial monolayer and a rapid collapse of the BBB. These data strongly suggest the involvement of Stx2e in cerebral vascular damage with resultant neurological disturbance characteristic of edema disease.

Socioeconomic status and adolescent e-cigarette use: The mediating role of e-cigarette advertisement exposure.

PubMed

Simon, Patricia; Camenga, Deepa R; Morean, Meghan E; Kong, Grace; Bold, Krysten W; Cavallo, Dana A; Krishnan-Sarin, Suchitra

2018-07-01

Among adolescents, low socioeconomic status (SES) is associated with greater exposure to tobacco cigarette advertising and cigarette use. However, associations among SES, e-cigarette advertising and e-cigarette use are not well understood. This study examined exposure to e-cigarette advertisements as a mediator of the relationship between SES and adolescent e-cigarette use. Adolescents (N = 3473; 51% Female) from 8 high schools in Connecticut completed an anonymous survey in Spring 2015. Mediation analysis was used to examine whether the total number of sources of recent e-cigarette advertising exposure (e.g., TV, radio, billboards, magazines, local stores [gas stations, convenience stores], vape shops, mall kiosks, tobacco shops, social media) mediated the association between SES (measured by the Family Affluence Scale) and past-month frequency of e-cigarette use. We clustered for school and controlled for other tobacco product use, age, sex, race/ethnicity and perceived social norms for e-cigarette use in the model. Our sample recently had seen advertisements via 2.1 (SD = 2.8) advertising channels. Mediation was supported (indirect effect: β = 0.01, SE = 0.00, 95% CI [0.001, 0.010], p = 0.02), such that higher SES was associated with greater recent advertising exposure, which, in turn, was associated with greater frequency of e-cigarette use. Our study suggests that regulations to reduce youth exposure to e-cigarette advertisement may be especially relevant to higher SES youth. Future research should examine these associations longitudinally and evaluate which types of advertisements target different SES groups. Copyright © 2018 Elsevier Inc. All rights reserved.

Modulation of translation-initiation in CHO-K1 cells by rapamycin-induced heterodimerization of engineered eIF4G fusion proteins.

PubMed

Schlatter, Stefan; Senn, Claudia; Fussenegger, Martin

2003-07-20

Translation-initiation is a predominant checkpoint in mammalian cells which controls protein synthesis and fine-tunes the flow of information from gene to protein. In eukaryotes, translation-initiation is typically initiated at a 7-methyl-guanylic acid cap posttranscriptionally linked to the 5' end of mRNAs. Alternative cap-independent translation-initiation involves 5' untranslated regions (UTR) known as internal ribosome entry sites, which adopt a particular secondary structure. Translation-initiating ribosome assembly at cap or IRES elements is mediated by a multiprotein complex of which the initiation factor 4F (eIF4F) consisting of eIF4A (helicase), eIF4E (cap-binding protein), and eIF4G is a major constituent. eIF4G is a key target of picornaviral protease 2A, which cleaves this initiation factor into eIF4G(Delta) and (Delta)eIF4G to redirect the cellular translation machinery exclusively to its own IRES-containing transcripts. We have designed a novel translation control system (TCS) for conditional as well as adjustable translation of cap- and IRES-dependent transgene mRNAs in mammalian cells. eIF4G(Delta) and (Delta)eIF4G were fused C- and N-terminally to the FK506-binding protein (FKBP) and the FKBP-rapamycin-binding domain (FRB) of the human FKBP-rapamycin-associated protein (FRAP), respectively. Rapamycin-induced heterodimerization of eIF4G(Delta)-FKBP and FRB-(Delta)eIF4G fusion proteins reconstituted a functional chimeric elongation factor 4G in a dose-dependent manner. Rigorous quantitative expression analysis of cap- and IRES-dependent SEAP- (human placental secreted alkaline phosphatase) and luc- (Photinus pyralis luciferase) encoding reporter constructs confirmed adjustable translation control and revealed increased production of desired proteins in response to dimerization-induced heterologous eIF4G in Chinese hamster ovary (CHO-K1) cells. Copyright 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 83: 210-225, 2003.

Time to symptom improvement using elimination diets in non-IgE-mediated gastrointestinal food allergies.

PubMed

Lozinsky, Adriana Chebar; Meyer, Rosan; De Koker, Claire; Dziubak, Robert; Godwin, Heather; Reeve, Kate; Dominguez Ortega, Gloria; Shah, Neil

2015-08-01

The prevalence of food allergy has increased in recent decades, and there is paucity of data on time to symptom improvement using elimination diets in non-Immunoglobulin E (IgE)-mediated food allergies. We therefore aimed to assess the time required to improvement of symptoms using a symptom questionnaire for children with non-IgE-mediated food allergies on an elimination diet. A prospective observational study was performed on patients with non-IgE-mediated gastrointestinal food allergies on an elimination diet, who completed a questionnaire that includes nine evidence-based food allergic symptoms before and after the exclusion diet. The questionnaire measured symptoms individually from 0 (no symptom) to 5 (most severe) and collectively from 0 to 45. Children were only enrolled in the study if collectively symptoms improved with the dietary elimination within 4 or 8 weeks. Data from 131 patients were analysed including 90 boys with a median age of 21 months [IQR: 7 to 66]. Based on the symptom questionnaire, 129 patients (98.4%) improved after 4-week elimination diet and only two patients improved after 8 weeks. A statistically significant difference before and after commencing the elimination diet was seen in all nine recorded symptoms (all p < 0.001), and in the median of overall score (p < 0.001). This is the first study attempting to establish time to improve after commencing the diet elimination. Almost all children in this study improved within 4 weeks of following the elimination diet, under dietary supervision. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Direct interaction of Ski with either Smad3 or Smad4 is necessary and sufficient for Ski-mediated repression of transforming growth factor-beta signaling.

PubMed

Ueki, Nobuhide; Hayman, Michael J

2003-08-29

The oncoprotein Ski represses transforming growth factor (TGF)-beta signaling in an N-CoR-independent manner. However, the molecular mechanism(s) underlying this event has not been elucidated. Here, we identify an additional domain in Ski that mediates interaction with Smad3 which is important for this repression. This domain is distinct from the previously reported N-terminal Smad3 binding domain in Ski. Individual alanine substitution of several residues in the domain significantly affected Ski-Smad3 interaction. Furthermore, combined mutations within this domain, together with those in the previously identified Smad3 binding domain, can completely abolish the interaction of Ski with Smad3, while mutation in each domain alone retained partial interaction. By introducing those mutations that abolish direct interaction with Smad3 or Smad4 individually, or in combination, we show that interaction of Ski with either Smad3 or Smad4 is sufficient for Ski-mediated repression of TGF-beta signaling. Furthermore our results clearly demonstrate that Ski does not disrupt Smad3-Smad4 heteromer formation, and recruitment of Ski to the Smad3/4 complex through binding to either Smad3 or Smad4 is both necessary and sufficient for repression.

Microphotochemistry: 4,4'-Dimethoxybenzophenone mediated photodecarboxylation reactions involving phthalimides

PubMed Central

Shvydkiv, Oksana; Nolan, Kieran

2011-01-01

Summary A series of 4,4'-dimethoxybenzophenone mediated intra- and intermolecular photodecarboxylation reactions involving phthalimides have been examined under microflow conditions. Conversion rates, isolated yields and chemoselectivities were compared to analogous reactions in a batch photoreactor. In all cases investigated, the microreactions gave superior results thus proving the superiority of microphotochemistry over conventional technologies. PMID:21915208

Tetraspanin TM4SF5 mediates loss of contact inhibition through epithelial-mesenchymal transition in human hepatocarcinoma

PubMed Central

Lee, Sin-Ae; Lee, Sung-Yul; Cho, Ik-Hyun; Oh, Min-A; Kang, Eun-Sil; Kim, Yong-Bae; Seo, Woo Duck; Choi, Suyong; Nam, Ju-Ock; Tamamori-Adachi, Mimi; Kitajima, Shigetaka; Ye, Sang-Kyu; Kim, Semi; Hwang, Yoon-Jin; Kim, In-San; Park, Ki Hun; Lee, Jung Weon

2008-01-01

The growth of normal cells is arrested when they come in contact with each other, a process known as contact inhibition. Contact inhibition is lost during tumorigenesis, resulting in uncontrolled cell growth. Here, we investigated the role of the tetraspanin transmembrane 4 superfamily member 5 (TM4SF5) in contact inhibition and tumorigenesis. We found that TM4SF5 was overexpressed in human hepatocarcinoma tissue. TM4SF5 expression in clinical samples and in human hepatocellular carcinoma cell lines correlated with enhanced p27Kip1 expression and cytosolic stabilization as well as morphological elongation mediated by RhoA inactivation. These TM4SF5-mediated effects resulted in epithelial-mesenchymal transition (EMT) via loss of E-cadherin expression. The consequence of this was aberrant cell growth, as assessed by S-phase transition in confluent conditions, anchorage-independent growth, and tumor formation in nude mice. The TM4SF5-mediated effects were abolished by suppressing the expression of either TM4SF5 or cytosolic p27Kip1, as well as by reconstituting the expression of E-cadherin. Our observations have revealed a role for TM4SF5 in causing uncontrolled growth of human hepatocarcinoma cells through EMT. PMID:18357344

Icaritin enhances mESC self-renewal through upregulating core pluripotency transcription factors mediated by ERα

PubMed Central

Tsang, Wing Pui; Zhang, Fengjie; He, Qiling; Cai, Waijiao; Huang, Jianhua; Chan, Wai Yee; Shen, Ziyin; Wan, Chao

2017-01-01

Utilization of small molecules in modulation of stem cell self-renewal is a promising approach to expand stem cells for regenerative therapy. Here, we identify Icaritin, a phytoestrogen molecule enhances self-renewal of mouse embryonic stem cells (mESCs). Icaritin increases mESCs proliferation while maintains their self-renewal capacity in vitro and pluripotency in vivo. This coincides with upregulation of key pluripotency transcription factors OCT4, NANOG, KLF4 and SOX2. The enhancement of mESCs self-renewal is characterized by increased population in S-phase of cell cycle, elevation of Cylin E and Cyclin-dependent kinase 2 (CDK2) and downregulation of p21, p27 and p57. PCR array screening reveals that caudal-related homeobox 2 (Cdx2) and Rbl2/p130 are remarkably suppressed in mESCs treated with Icaritin. siRNA knockdown of Cdx2 or Rbl2/p130 upregulates the expression of Cyclin E, OCT4 and SOX2, and subsequently increases cell proliferation and colony forming efficiency of mESCs. We then demonstrate that Icaritin co-localizes with estrogen receptor alpha (ERα) and activates its nuclear translocation in mESCs. The promotive effect of Icaritin on cell cycle and pluripotency regulators are eliminated by siRNA knockdown of ERα in mESCs. The results suggest that Icaritin enhances mESCs self-renewal by regulating cell cycle machinery and core pluripotency transcription factors mediated by ERα. PMID:28091581

Icaritin enhances mESC self-renewal through upregulating core pluripotency transcription factors mediated by ERα.

PubMed

Tsang, Wing Pui; Zhang, Fengjie; He, Qiling; Cai, Waijiao; Huang, Jianhua; Chan, Wai Yee; Shen, Ziyin; Wan, Chao

2017-01-16

Utilization of small molecules in modulation of stem cell self-renewal is a promising approach to expand stem cells for regenerative therapy. Here, we identify Icaritin, a phytoestrogen molecule enhances self-renewal of mouse embryonic stem cells (mESCs). Icaritin increases mESCs proliferation while maintains their self-renewal capacity in vitro and pluripotency in vivo. This coincides with upregulation of key pluripotency transcription factors OCT4, NANOG, KLF4 and SOX2. The enhancement of mESCs self-renewal is characterized by increased population in S-phase of cell cycle, elevation of Cylin E and Cyclin-dependent kinase 2 (CDK2) and downregulation of p21, p27 and p57. PCR array screening reveals that caudal-related homeobox 2 (Cdx2) and Rbl2/p130 are remarkably suppressed in mESCs treated with Icaritin. siRNA knockdown of Cdx2 or Rbl2/p130 upregulates the expression of Cyclin E, OCT4 and SOX2, and subsequently increases cell proliferation and colony forming efficiency of mESCs. We then demonstrate that Icaritin co-localizes with estrogen receptor alpha (ERα) and activates its nuclear translocation in mESCs. The promotive effect of Icaritin on cell cycle and pluripotency regulators are eliminated by siRNA knockdown of ERα in mESCs. The results suggest that Icaritin enhances mESCs self-renewal by regulating cell cycle machinery and core pluripotency transcription factors mediated by ERα.

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.

The mediating effect of psychosocial factors on suicidal probability among adolescents.

PubMed

Hur, Ji-Won; Kim, Won-Joong; Kim, Yong-Ku

2011-01-01

Suicidal probability is an actual tendency including negative self-evaluation, hopelessness, suicidal ideation, and hostility. The purpose of this study was to examine the role of psychosocial variances in the suicidal probability of adolescents, especially the role of mediating variance. This study investigated the mediating effects of psychosocial factors such as depression, anxiety, self-esteem, stress, and social support on the suicidal probability among 1,586 adolescents attending middle and high schools in the Kyunggi Province area of South Korea. The relationship between depression and anxiety/suicidal probability was mediated by both social resources and self-esteem. Furthermore, the influence of social resources was mediated by interpersonal and achievement stress as well as self-esteem. This study suggests that suicidal probability in adolescents has various relationships, including mediating relations, with several psychosocial factors. The interventions on suicidal probability in adolescents should focus on social factors as well as clinical symptoms.

Downregulation of Homologous Recombination DNA Repair Genes by HDAC Inhibition in Prostate Cancer Is Mediated through the E2F1 Transcription Factor

PubMed Central

Kachhap, Sushant K.; Rosmus, Nadine; Collis, Spencer J.; Kortenhorst, Madeleine S. Q.; Wissing, Michel D.; Hedayati, Mohammad; Shabbeer, Shabana; Mendonca, Janet; Deangelis, Justin; Marchionni, Luigi; Lin, Jianqing; Höti, Naseruddin; Nortier, Johan W. R.; DeWeese, Theodore L.; Hammers, Hans; Carducci, Michael A.

2010-01-01

Background Histone deacetylase inhibitors (HDACis) re-express silenced tumor suppressor genes and are currently undergoing clinical trials. Although HDACis have been known to induce gene expression, an equal number of genes are downregulated upon HDAC inhibition. The mechanism behind this downregulation remains unclear. Here we provide evidence that several DNA repair genes are downregulated by HDAC inhibition and provide a mechanism involving the E2F1 transcription factor in the process. Methodology/Principal Findings Applying Analysis of Functional Annotation (AFA) on microarray data of prostate cancer cells treated with HDACis, we found a number of genes of the DNA damage response and repair pathways are downregulated by HDACis. AFA revealed enrichment of homologous recombination (HR) DNA repair genes of the BRCA1 pathway, as well as genes regulated by the E2F1 transcription factor. Prostate cancer cells demonstrated a decreased DNA repair capacity and an increased sensitization to chemical- and radio-DNA damaging agents upon HDAC inhibition. Recruitment of key HR repair proteins to the site of DNA damage, as well as HR repair capacity was compromised upon HDACi treatment. Based on our AFA data, we hypothesized that the E2F transcription factors may play a role in the downregulation of key repair genes upon HDAC inhibition in prostate cancer cells. ChIP analysis and luciferase assays reveal that the downregulation of key repair genes is mediated through decreased recruitment of the E2F1 transcription factor and not through active repression by repressive E2Fs. Conclusions/Significance Our study indicates that several genes in the DNA repair pathway are affected upon HDAC inhibition. Downregulation of the repair genes is on account of a decrease in amount and promoter recruitment of the E2F1 transcription factor. Since HDAC inhibition affects several pathways that could potentially have an impact on DNA repair, compromised DNA repair upon HDAC inhibition could

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.

Insulin-like growth factor 1: common mediator of multiple enterotrophic hormones and growth factors.

PubMed

Bortvedt, Sarah F; Lund, P Kay

2012-03-01

To summarize the recent evidence that insulin-like growth factor 1 (IGF1) mediates growth effects of multiple trophic factors and discuss clinical relevance. Recent reviews and original reports indicate benefits of growth hormone (GH) and long-acting glucagon-like peptide 2 (GLP2) analogs in short bowel syndrome and Crohn's disease. This review highlights the evidence that biomarkers of sustained small intestinal growth or mucosal healing and evaluation of intestinal epithelial stem cell biomarkers may improve clinical measures of intestinal growth or response to trophic hormones. Compelling evidence that IGF1 mediates growth effects of GH and GLP2 on intestine or linear growth in preclinical models of resection or Crohn's disease is presented, along with a concept that these hormones or IGF1 may enhance sustained growth if given early after bowel resection. Evidence that suppressor of cytokine signaling protein induction by GH or GLP2 in normal or inflamed intestine may limit IGF1-induced growth, but protect against risk of dysplasia or fibrosis, is reviewed. Whether IGF1 receptor mediates IGF1 action and potential roles of insulin receptors are addressed. IGF1 has a central role in mediating trophic hormone action in small intestine. Better understanding of benefits and risks of IGF1, receptors that mediate IGF1 action, and factors that limit undesirable growth are needed.

Kelch-like ECH-associated Protein 1-dependent Nuclear Factor-E2-related Factor 2 Activation in Relation to Antioxidation Induced by Sevoflurane Preconditioning.

PubMed

Cai, Min; Tong, Li; Dong, Beibei; Hou, Wugang; Shi, Likai; Dong, Hailong

2017-03-01

The authors have reported that antioxidative effects play a crucial role in the volatile anesthetic-induced neuroprotection. Accumulated evidence shows that endogenous antioxidation could be up-regulated by nuclear factor-E2-related factor 2 through multiple pathways. However, whether nuclear factor-E2-related factor 2 activation is modulated by sevoflurane preconditioning and, if so, what is the signaling cascade underlying upstream of this activation are still unknown. Sevoflurane preconditioning in mice was performed with sevoflurane (2.5%) 1 h per day for five consecutive days. Focal cerebral ischemia/reperfusion injury was induced by middle cerebral artery occlusion. Expression of nuclear factor-E2-related factor 2, kelch-like ECH-associated protein 1, manganese superoxide dismutase, thioredoxin-1, and nicotinamide adenine dinucleotide phosphate quinolone oxidoreductase-1 was detected (n = 6). The antioxidant activities and oxidative product expression were also examined. To determine the role of kelch-like ECH-associated protein 1 inhibition-dependent nuclear factor-E2-related factor 2 activation in sevoflurane preconditioning-induced neuroprotection, the kelch-like ECH-associated protein 1-nuclear factor-E2-related factor 2 signal was modulated by nuclear factor-E2-related factor 2 knockout, kelch-like ECH-associated protein 1 overexpression lentivirus, and kelch-like ECH-associated protein 1 deficiency small interfering RNA (n = 8). The infarct volume, neurologic scores, and cellular apoptosis were assessed. Sevoflurane preconditioning elicited neuroprotection and increased nuclear factor-E2-related factor 2 nuclear translocation, which in turn up-regulated endogenous antioxidation and reduced oxidative injury. Sevoflurane preconditioning reduced kelch-like ECH-associated protein 1 expression. Nuclear factor-E2-related factor 2 ablation abolished neuroprotection and reversed sevoflurane preconditioning by mediating the up-regulation of antioxidants. Kelch

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

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.

Iron-Binding E3 Ligase Mediates Iron Response in Plants by Targeting Basic Helix-Loop-Helix Transcription Factors1[OPEN

PubMed Central

Selote, Devarshi; Samira, Rozalynne; Matthiadis, Anna; Gillikin, Jeffrey W.; Long, Terri A.

2015-01-01

Iron uptake and metabolism are tightly regulated in both plants and animals. In Arabidopsis (Arabidopsis thaliana), BRUTUS (BTS), which contains three hemerythrin (HHE) domains and a Really Interesting New Gene (RING) domain, interacts with basic helix-loop-helix transcription factors that are capable of forming heterodimers with POPEYE (PYE), a positive regulator of the iron deficiency response. BTS has been shown to have E3 ligase capacity and to play a role in root growth, rhizosphere acidification, and iron reductase activity in response to iron deprivation. To further characterize the function of this protein, we examined the expression pattern of recombinant ProBTS::β-GLUCURONIDASE and found that it is expressed in developing embryos and other reproductive tissues, corresponding with its apparent role in reproductive growth and development. Our findings also indicate that the interactions between BTS and PYE-like (PYEL) basic helix-loop-helix transcription factors occur within the nucleus and are dependent on the presence of the RING domain. We provide evidence that BTS facilitates 26S proteasome-mediated degradation of PYEL proteins in the absence of iron. We also determined that, upon binding iron at the HHE domains, BTS is destabilized and that this destabilization relies on specific residues within the HHE domains. This study reveals an important and unique mechanism for plant iron homeostasis whereby an E3 ubiquitin ligase may posttranslationally control components of the transcriptional regulatory network involved in the iron deficiency response. PMID:25452667

The COOH-terminal peptide of platelet factor-4 variant (CXCL4L1/PF-4var47-70) strongly inhibits angiogenesis and suppresses B16 melanoma growth in vivo.

PubMed

Vandercappellen, Jo; Liekens, Sandra; Bronckaers, Annelies; Noppen, Samuel; Ronsse, Isabelle; Dillen, Chris; Belleri, Mirella; Mitola, Stefania; Proost, Paul; Presta, Marco; Struyf, Sofie; Van Damme, Jo

2010-03-01

Chemokines influence tumor growth directly or indirectly via both angiogenesis and tumor-leukocyte interactions. Platelet factor-4 (CXCL4/PF-4), which is released from alpha-granules of activated platelets, is the first described angiostatic chemokine. Recently, it was found that the variant of CXCL4/PF-4 (CXCL4L1/PF-4var) could exert a more pronounced angiostatic and antitumoral effect than CXCL4/PF-4. However, the molecular mechanisms of the angiostatic activities of the PF-4 forms remain partially elusive. Here, we studied the biological properties of the chemically synthesized COOH-terminal peptides of CXCL4/PF-4 (CXCL4/PF-4(47-70)) and CXCL4L1/PF-4var (CXCL4L1/PF-4var(47-70)). Both PF-4 peptides lacked monocyte and lymphocyte chemotactic activity but equally well inhibited (25 nmol/L) endothelial cell motility and proliferation in the presence of a single stimulus (i.e., exogenous recombinant fibroblast growth factor-2). In contrast, when assayed in more complex angiogenesis test systems characterized by the presence of multiple mediators, including in vitro wound-healing (2.5 nmol/L versus 12.5 nmol/L), Matrigel (60 nmol/L versus 300 nmol/L), and chorioallantoic membrane assays, CXCL4L1/PF-4var(47-70) was found to be significantly (5-fold) more angiostatic than CXCL4/PF-4(47-70). In addition, low (7 microg total) doses of intratumoral CXCL4L1/PF-4var(47-70) inhibited B16 melanoma growth in mice more extensively than CXCL4/PF-4(47-70). This antitumoral activity was predominantly mediated through inhibition of angiogenesis (without affecting blood vessel stability) and induction of apoptosis, as evidenced by immunohistochemical and fluorescent staining of B16 tumor tissue. In conclusion, CXCL4L1/PF-4var(47-70) is a potent antitumoral and antiangiogenic peptide. These results may represent the basis for the design of CXCL4L1/PF-4var COOH-terminal-derived peptidomimetic anticancer drugs.

Practical interest of both skin prick test and specific IgE in the evaluation of tolerance acquisition in IgE mediated cow's milk allergy (CMA). A clinical retrospective study in a cohort of 184 children.

PubMed

Payot, F; Berthiller, J; Kassai, B; Brunet, A-S; Villard-Truc, F; Lachaux, A

2014-01-01

Cow's milk protein allergy (CMPA) represents one of the leading causes of food allergy in infants and young children. The immune reaction may be IgE mediated, non-IgE mediated, or mixed. IgE-mediated cow's milk protein allergy is revealed by immediate and acute symptoms which can be severe. The aim of this study is to report a one centre experience in the real life of testing children with IgE-mediated CMPA and try to identify predictive factor for follow-up challenges. Retrospective and monocentric study between September 1997 and February 2008. 178 infants diagnosed with IgE-mediated CMPA during breastfeeding weaning were included. Initial factors such as age, sex, skin prick tests (SPTs), specific IgE (sIgE), atopic dermatitis and types of reaction were noted. Between 12 and 24 months all infants have undergone at least one evaluation including SPT. At the food challenge, 138 (75.8%) infants were found tolerant. Results of the skin prick test (SPT) were statistically different according to the food challenge result (2.2mm vs. 5.1mm, p<0.0001). It was the same result for sIgE for CM 2.0ku/l vs. 11.5ku/l - p<0.0001 and for casein 1.0ku/l vs. 16.0ku/l - p=0.0014. This study confirms the practical interest of both SPT and sIgE in the evaluation of tolerance induction in IgE-mediated CMPA, but with no corresponding results. Sensitivity, specificity and probability curves of success for cow's milk challenge can be determined and have clinical utility. Copyright © 2013 SEICAP. Published by Elsevier Espana. All rights reserved.

Social Differentiation of Sun-Protection Behaviors: The Mediating Role of Cognitive Factors.

PubMed

Bocquier, Aurélie; Fressard, Lisa; Legleye, Stéphane; Verger, Pierre; Peretti-Watel, Patrick

2016-03-01

Adherence to sun-protection guidelines in developed countries is low, especially among people of low SES. Mechanisms underlying this social differentiation are poorly understood. This study aimed to examine the social differentiation of sun-protection behaviors and of two cognitive factors (knowledge about both sun health and behavioral risk factors for cancer) and to determine if these cognitive factors mediate the association between SES and sun-protection behaviors. Data came from the 2010 Baromètre Cancer survey (analyzed in 2014), a random cross-sectional telephone survey conducted among the French general population (n=3,359 individuals aged 15-75 years). First, bivariate associations between a composite individual SES indicator (based on education level, occupation, and income) and both sun-protection behaviors and cognitive factors were tested with chi-square tests and ANOVA. Then, confirmatory factor analysis and structural equation modeling were used to test the mediating role of cognitive factors with a multiple mediation model including four latent variables. In bivariate analyses, the individual SES indicator was positively associated with sun-protection behaviors and both cognitive factors. Multiple mediation analyses showed that both cognitive factors partially mediated the effect of individual SES on sun-protection behaviors. The overall proportion of mediated effects was 48%. The direct effect of SES remained significant. These results suggest that interventions aimed at modifying the knowledge and perceptions of people of low SES might help to reduce social differentiation of sun-protection behaviors. Further qualitative research is needed to better understand these cognitive factors and develop suitable prevention messages. Copyright © 2016 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Non-IgE mediated mast cell activation.

PubMed

Redegeld, Frank A; Yu, Yingxin; Kumari, Sangeeta; Charles, Nicolas; Blank, Ulrich

2018-03-01

Mast cells (MCs) are innate immune cells that are scattered in tissues throughout the organism being particularly abundant at sites exposed to the environment such as the skin and mucosal surfaces. Generally known for their role in IgE-mediated allergies, they have also important functions in the maintenance of tissue integrity by constantly sensing their microenvironment for signals by inflammatory triggers that can comprise infectious agents, toxins, hormones, alarmins, metabolic states, etc. When triggered their main function is to release a whole set of inflammatory mediators, cytokines, chemokines, and lipid products. This allows them to organize the ensuing innate immune and inflammatory response in tight coordination with resident tissue cells, other rapidly recruited immune effector cells as well as the endocrine and exocrine systems of the body. To complete these tasks, MCs are endowed with a large repertoire of receptors allowing them to respond to multiple stimuli or directly interact with other cells. Here we review some of the receptors expressed on MCs (ie, receptors for Immunoglobulins, pattern recognition receptors, nuclear receptors, receptors for alarmins, and a variety of other receptors) and discuss their functional implication in the immune and inflammatory response focusing on non-IgE-mediated activation mechanisms. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Plasmid-mediated bioaugmentation of sequencing batch reactors for enhancement of 2,4-dichlorophenoxyacetic acid removal in wastewater using plasmid pJP4.

PubMed

Tsutsui, Hirofumi; Anami, Yasutaka; Matsuda, Masami; Hashimoto, Kurumi; Inoue, Daisuke; Sei, Kazunari; Soda, Satoshi; Ike, Michihiko

2013-06-01

Plasmid-mediated bioaugmentation was demonstrated using sequencing batch reactors (SBRs) for enhancing 2,4-dichlorophenoxyacetic acid (2,4-D) removal by introducing Cupriavidus necator JMP134 and Escherichia coli HB101 harboring 2,4-D-degrading plasmid pJP4. C. necator JMP134(pJP4) can mineralize and grow on 2,4-D, while E. coli HB101(pJP4) cannot assimilate 2,4-D because it lacks the chromosomal genes to degrade the intermediates. The SBR with C. necator JMP134(pJP4) showed 100 % removal against 200 mg/l of 2,4-D just after its introduction, after which 2,4-D removal dropped to 0 % on day 7 with the decline in viability of the introduced strain. The SBR with E. coli HB101(pJP4) showed low 2,4-D removal, i.e., below 10 %, until day 7. Transconjugant strains of Pseudomonas and Achromobacter isolated on day 7 could not grow on 2,4-D. Both SBRs started removing 2,4-D at 100 % after day 16 with the appearance of 2,4-D-degrading transconjugants belonging to Achromobacter, Burkholderia, Cupriavidus, and Pandoraea. After the influent 2,4-D concentration was increased to 500 mg/l on day 65, the SBR with E. coli HB101(pJP4) maintained stable 2,4-D removal of more than 95 %. Although the SBR with C. necator JMP134(pJP4) showed a temporal depression of 2,4-D removal of 65 % on day 76, almost 100 % removal was achieved thereafter. During this period, transconjugants isolated from both SBRs were mainly Achromobacter with high 2,4-D-degrading capability. In conclusion, plasmid-mediated bioaugmentation can enhance the degradation capability of activated sludge regardless of the survival of introduced strains and their 2,4-D degradation capacity.

Global Analysis of Salmonella Alternative Sigma Factor E on Protein Translation

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

Li, Jie; Nakayasu, Ernesto S.; Overall, Christopher C.

The alternative sigma factor E (σ E) is critical for response to extracytoplasmic stress in Salmonella. Extensive studies have been conducted on σ E-regulated gene expression, particularly at the transcriptional level. Increasing evidence suggests however that σ E may indirectly participate in post-transcriptional regulation. Here in this study, we conducted sample-matched global proteomic and transcriptomic analyses to determine the level of regulation mediated by σ E in Salmonella. We analysed samples from wild type and isogenic rpoE mutant Salmonella cultivated in three different conditions; nutrient-rich and conditions that mimic early and late intracellular infection. We found that 30% of themore » observed proteome was regulated by σ E combining all three conditions. In different growth conditions, σ E affected the expression of a broad spectrum of Salmonella proteins required for miscellaneous functions. Those involved in transport and binding, protein synthesis, and stress response were particularly highlighted. By comparing transcriptomic and proteomic data, we identified genes post-transcriptionally regulated by σ E and found that post-transcriptional regulation was responsible for a majority of changes observed in the σ E-regulated proteome. Further, comparison of transcriptomic and proteomic data from hfq mutant of Salmonella demonstrated that σ E–mediated post-transcriptional regulation was partially dependent on the RNA-binding protein Hfq.« less

Global Analysis of Salmonella Alternative Sigma Factor E on Protein Translation

DOE PAGES

Li, Jie; Nakayasu, Ernesto S.; Overall, Christopher C.; ...

2015-02-16

The alternative sigma factor E (σ E) is critical for response to extracytoplasmic stress in Salmonella. Extensive studies have been conducted on σ E-regulated gene expression, particularly at the transcriptional level. Increasing evidence suggests however that σ E may indirectly participate in post-transcriptional regulation. Here in this study, we conducted sample-matched global proteomic and transcriptomic analyses to determine the level of regulation mediated by σ E in Salmonella. We analysed samples from wild type and isogenic rpoE mutant Salmonella cultivated in three different conditions; nutrient-rich and conditions that mimic early and late intracellular infection. We found that 30% of themore » observed proteome was regulated by σ E combining all three conditions. In different growth conditions, σ E affected the expression of a broad spectrum of Salmonella proteins required for miscellaneous functions. Those involved in transport and binding, protein synthesis, and stress response were particularly highlighted. By comparing transcriptomic and proteomic data, we identified genes post-transcriptionally regulated by σ E and found that post-transcriptional regulation was responsible for a majority of changes observed in the σ E-regulated proteome. Further, comparison of transcriptomic and proteomic data from hfq mutant of Salmonella demonstrated that σ E–mediated post-transcriptional regulation was partially dependent on the RNA-binding protein Hfq.« less

TAFII-independent activation mediated by human TBP in the presence of the positive cofactor PC4.

PubMed Central

Wu, S Y; Kershnar, E; Chiang, C M

1998-01-01

TFIID is a multiprotein complex comprised of the TATA-binding protein (TBP) and an array of TBP-associated factors (TAFIIs). Whereas TBP is sufficient for basal transcription in conjunction with other general transcription factors and RNA polymerase II, TAFIIs are additionally required for activator-dependent transcription in mammalian cell-free transcription systems. However, recent in vivo studies carried out in yeast suggest that TAFIIs are not globally required for activator function. The discrepancy between in vivo yeast studies and in vitro mammalian cell-free systems remains to be resolved. In this study, we describe a mammalian cell-free transcription system reconstituted with only recombinant proteins and epitope-tagged multiprotein complexes. Transcriptional activation can be recapitulated in this highly purified in vitro transcription system in the absence of TAFIIs. This TBP-mediated activation is not induced by human mediator, another transcriptional coactivator complex potentially implicated in activator response. In contrast, general transcription factors TFIIH and TFIIA play a significant role in TBP-mediated activation, which can be detected in vitro with Gal4 fusion proteins containing various transcriptional activation domains. Our data, therefore, suggest that TFIIH and TFIIA can mediate activator function in the absence of TAFIIs. PMID:9687514

Trim25 Is an RNA-Specific Activator of Lin28a/TuT4-Mediated Uridylation.

PubMed

Choudhury, Nila Roy; Nowak, Jakub S; Zuo, Juan; Rappsilber, Juri; Spoel, Steven H; Michlewski, Gracjan

2014-11-20

RNA binding proteins have thousands of cellular RNA targets and often exhibit opposite or passive molecular functions. Lin28a is a conserved RNA binding protein involved in pluripotency and tumorigenesis that was previously shown to trigger TuT4-mediated pre-let-7 uridylation, inhibiting its processing and targeting it for degradation. Surprisingly, despite binding to other pre-microRNAs (pre-miRNAs), only pre-let-7 is efficiently uridylated by TuT4. Thus, we hypothesized the existence of substrate-specific cofactors that stimulate Lin28a-mediated pre-let-7 uridylation or restrict its functionality on non-let-7 pre-miRNAs. Through RNA pull-downs coupled with quantitative mass spectrometry, we identified the E3 ligase Trim25 as an RNA-specific cofactor for Lin28a/TuT4-mediated uridylation. We show that Trim25 binds to the conserved terminal loop (CTL) of pre-let-7 and activates TuT4, allowing for more efficient Lin28a-mediated uridylation. These findings reveal that protein-modifying enzymes, only recently shown to bind RNA, can guide the function of canonical ribonucleoprotein (RNP) complexes in cis, thereby providing an additional level of specificity.

Is e+e- pair emission important in the determination of the 3He+4He S factor?

NASA Astrophysics Data System (ADS)

Snover, K. A.; Hurd, A. E.

2003-05-01

We show that the cross section for direct E0 pair emission is related to the cross section for direct E2 photon emission, and is a negligible contribution to the total capture cross section for 3He+4He→7Be. E0 resonance emission, E1 pair emission, and internal conversion are also negligible. Thus there cannot be significant contributions to the 3He+4He→7Be capture cross section at low energies from electromagnetic emission processes other than single photon emission.

Macrophage Migration Inhibitory Factor-CXCR4 Receptor Interactions

PubMed Central

Rajasekaran, Deepa; Gröning, Sabine; Schmitz, Corinna; Zierow, Swen; Drucker, Natalie; Bakou, Maria; Kohl, Kristian; Mertens, André; Lue, Hongqi; Weber, Christian; Xiao, Annie; Luker, Gary; Kapurniotu, Aphrodite; Lolis, Elias; Bernhagen, Jürgen

2016-01-01

An emerging number of non-chemokine mediators are found to bind to classical chemokine receptors and to elicit critical biological responses. Macrophage migration inhibitory factor (MIF) is an inflammatory cytokine that exhibits chemokine-like activities through non-cognate interactions with the chemokine receptors CXCR2 and CXCR4, in addition to activating the type II receptor CD74. Activation of the MIF-CXCR2 and -CXCR4 axes promotes leukocyte recruitment, mediating the exacerbating role of MIF in atherosclerosis and contributing to the wealth of other MIF biological activities. Although the structural basis of the MIF-CXCR2 interaction has been well studied and was found to engage a pseudo-ELR and an N-like loop motif, nothing is known about the regions of CXCR4 and MIF that are involved in binding to each other. Using a genetic strain of Saccharomyces cerevisiae that expresses a functional CXCR4 receptor, site-specific mutagenesis, hybrid CXCR3/CXCR4 receptors, pharmacological reagents, peptide array analysis, chemotaxis, fluorescence spectroscopy, and circular dichroism, we provide novel molecular information about the structural elements that govern the interaction between MIF and CXCR4. The data identify similarities with classical chemokine-receptor interactions but also provide evidence for a partial allosteric agonist compared with CXCL12 that is possible due to the two binding sites of CXCR4. PMID:27226569

Exploring socio-cultural factors that mediate, facilitate, & constrain the health and empowerment of refugee youth.

PubMed

Edge, Sara; Newbold, K Bruce; McKeary, Marie

2014-09-01

Studies on youth health and well-being are predominantly quantitative and expert-driven with less attention given to how youth understand what it means to be healthy themselves and the role of socio-cultural factors in shaping this. Knowledge on the perceptions and experiences of refugee youth is particularly lacking and notable given their unique stressors related to migratory, settlement and integration experiences. We contribute a better understanding of how refugee youth themselves define and contextualize health, with particular emphasis given to socio-cultural factors that enable or constrain health promotion efforts and individual health agency. This research was undertaken at a downtown drop-in centre in Hamilton, Ontario, Canada that provided settlement and integration services to newcomer youth. We employ a grounded theory approach and draw upon participant observation, focus groups and in-depth interviews. Twenty-six youth (age 18-25 years), representing 12 different countries of origin participated. The youth defined health very broadly touching upon many typical determinants of health (e.g. education, income, etc.). Yet factors of most importance (as demonstrated by the frequency and urgency in which they were discussed by youth) included a sense of belonging, positive self-identity, emotional well-being, and sense of agency or self-determination. We conceptualize these as "mediating" factors given the youth argued they enabled or constrained their ability to cope with adversities related to other health determinant categories. The youth also discussed what we interpret as "facilitators" that encourage mediating factors to manifest positively (e.g. informal, non-biomedical settings and programs that nurture trust, break down access barriers, and promote a sense of community amongst peers, mentors, and health professionals). When creating health promotion strategies for refugee youth (and perhaps youth more generally) it is important to understand the

Cap-proximal nucleotides via differential eIF4E binding and alternative promoter usage mediate translational response to energy stress.

PubMed

Tamarkin-Ben-Harush, Ana; Vasseur, Jean-Jacques; Debart, Françoise; Ulitsky, Igor; Dikstein, Rivka

2017-02-08

Transcription start-site (TSS) selection and alternative promoter (AP) usage contribute to gene expression complexity but little is known about their impact on translation. Here we performed TSS mapping of the translatome following energy stress. Assessing the contribution of cap-proximal TSS nucleotides, we found dramatic effect on translation only upon stress. As eIF4E levels were reduced, we determined its binding to capped-RNAs with different initiating nucleotides and found the lowest affinity to 5'cytidine in correlation with the translational stress-response. In addition, the number of differentially translated APs was elevated following stress. These include novel glucose starvation-induced downstream transcripts for the translation regulators eIF4A and Pabp, which are also translationally-induced despite general translational inhibition. The resultant eIF4A protein is N-terminally truncated and acts as eIF4A inhibitor. The induced Pabp isoform has shorter 5'UTR removing an auto-inhibitory element. Our findings uncovered several levels of coordination of transcription and translation responses to energy stress.

NOD2 Down-Regulates Colonic Inflammation by IRF4-Mediated Inhibition of K63-Linked Polyubiquitination of RICK and TRAF6

PubMed Central

Watanabe, Tomohiro; Asano, Naoki; Meng, Guangxun; Yamashita, Kouhei; Arai, Yasuyuki; Sakurai, Toshiharu; Kudo, Masatoshi; Fuss, Ivan J; Kitani, Atsushi; Shimosegawa, Tooru; Chiba, Tsutomu; Strober, Warren

2014-01-01

It is well established that polymorphisms of the nucleotide-binding oligomerization domain 2 (NOD2) gene, a major risk factor in Crohn's disease (CD), lead to loss of NOD2 function. However, a molecular explanation of how such loss of function leads to increased susceptibility to CD has remained unclear. In a previous study exploring this question we reported that activation of NOD2 in human dendritic cells by its ligand, muramyl dipeptide (MDP) negatively regulates Toll-like receptor (TLR)-mediated inflammatory responses. Here we show that NOD2 activation results in increased interferon regulatory factor 4 (IRF4) expression and binding to TNF receptor associated factor 6 (TRAF6) and receptor interacting serine-threonine kinase (RICK). We then show that such binding leads to IRF4-mediated inhibition of Lys63-linked polyubiquitination of TRAF6 and RICK and thus to down-regulation of NF-κB activation. Finally, we demonstrate that protection of mice from the development of experimental colitis by MDP or IRF4 administration is accompanied by similar IRF4-mediated effects on polyubiquitination of TRAF6 and RICK in colonic lamina propria mononuclear cells. These findings thus define a mechanism of NOD2-mediated regulation of innate immune responses to intestinal microflora that could explain the relation of NOD2 polymorphisms and resultant NOD2 dysfunction to CD. PMID:24670424

Prospective and Retrospective Processing in Associative Mediated Priming

ERIC Educational Resources Information Center

Jones, Lara L.

2012-01-01

Mediated priming refers to the faster word recognition of a target (e.g., milk) following presentation of a prime (e.g., pasture) that is related indirectly via a connecting "mediator" (e.g., cow). Association strength may be an important factor in whether mediated priming occurs prospectively (with target activation prior to its presentation) or…

HEAT SHOCK FACTOR 1-MEDIATED THERMOTOLERANCE PREVENTS CELL DEATH AND RESULTS IN G2/M CELL CYCLE ARREST

EPA Science Inventory

Mammalian cells respond to stress by activating heat shock transcription factors (e.g., HSF1) that regulate increased synthesis of heat shock proteins (HSPs). HSPs mediate protection from deleterious effects of stress by preventing permanent disruption of normal cellular mitosis...

Potentiation of Schaffer-Collateral CA1 Synaptic Transmission by eEF2K and p38 MAPK Mediated Mechanisms.

PubMed

Weng, Weiguang; Chen, Ying; Wang, Man; Zhuang, Yinghan; Behnisch, Thomas

2016-01-01

The elongation factor 2 kinase (eEF2K), likewise known as CaMKIII, has been demonstrated to be involved in antidepressant responses of NMDA receptor antagonists. Even so, it remains open whether direct inhibition of eEF2K without altering up-stream or other signaling pathways affects hippocampal synaptic transmission and neuronal network synchrony. Inhibition of eEF2K by the selective and potent eEF2K inhibitor A-484954 induced a fast pre-synaptically mediated enhancement of synaptic transmission and synchronization of neural network activity. The eEF2K-inhibition mediated potentiation of synaptic transmission of hippocampal CA1 neurons is most notably independent of protein synthesis and does not rely on protein kinase C, protein kinase A or mitogen-activated protein kinase (MAPK)/extracellular signal-regulated protein kinase 1/2. Moreover, the strengthening of synaptic transmission in the response to the inhibition of eEF2K was strongly attenuated by the inhibition of p38 MAPK. In addition, we show the involvement of barium-sensitive and more specific the TWIK-related potassium-1 (TREK-1) channels in the eEF2K-inhibition mediated potentiation of synaptic transmission. These findings reveal a novel pathway of eEF2K mediated regulation of hippocampal synaptic transmission. Further research is required to study whether such compounds could be beneficial for the development of mood disorder treatments with a fast-acting antidepressant response.

Transnitrosylation: A Factor in Nitric Oxide-Mediated Penile Erection

PubMed Central

Goetz, Tabitha; La Favor, Justin D.; Burnett, Arthur L.

2016-01-01

Introduction Nitric oxide (NO) signaling can be mediated not only through classical cGMP, but also through S-nitrosylation. The impact of S-nitrosylation on erectile function and in NO regulation and oxidative stress in the penis, however, remains poorly understood. Aims To characterize the role of GSNOR, a major regulator of S-nitrosylation homeostasis, on erection physiology and on eNOS function and oxidative/nitrosative stress in the penis. Materials and Methods Adult GSNOR-deficient and WT mice were used. Erectile function was assessed in response to electrical stimulation of the cavernous nerve. Total NO in penile homogenates was measured by Griess reaction. Protein S-nitrosylation, endothelial NO synthase (eNOS) phosphorylation on Ser-1177 (positive regulatory site), eNOS uncoupling, and markers of oxidative stress (4-hydroxy-2-nonenal [4-HNE], malondialdehyde, and nitrotyrosine) in the penis were measured by Western blot. Main outcome measures Erectile function, eNOS function and oxidative stress in the penis of GSNOR-deficient mice. Results Erectile function was intact in GSNOR-deficient mice. Total S-nitrosylated proteins were increased (p<0.05) in the GSNOR−/− compared to WT mouse penis. While eNOS phosphorylation on Ser-1177 did not differ between the GSNOR−/− and WT mouse penis at baseline, electrical stimulation of the cavernous nerve increased (p<0.05) P-eNOS in the WT mouse penis, but failed to increase P-eNOS in the GSNOR−/− mouse penis. Total NO production was decreased (p<0.05), while eNOS uncoupling, 4-HNE, malondialdehyde, and nitrotyrosine were increased (p<0.05) in the GSNOR-deficient mouse penis compared to that of WT mice. Conclusion Transnitrosylation mechanisms play an important role in regulating NO bioactivity in the penis. Deficiency of GSNOR leads to eNOS dysfunction and increased oxidative damage, suggesting that homeostatic eNOS function in the penis is governed by transnitrosylation. PMID:27114194

Epidermal growth factor regulation of glutathione S-transferase gene expression in the rat is mediated by class Pi glutathione S-transferase enhancer I.

PubMed

Matsumoto, M; Imagawa, M; Aoki, Y

2000-07-01

Using chloramphenicol acetyltransferase assays we showed that epidermal growth factor (EGF), transforming growth factor alpha (TGF alpha), and 3,3',4,4',5-pentachlorobiphenyl (PenCB) induce class Pi glutathione S-transferase (GSTP1) in primary cultured rat liver parenchymal cells. GSTP1 enhancer I (GPEI), which is required for the stimulation of GSTP1 expression by PenCB, also mediates EGF and TGF alpha stimulation of GSTP1 gene expression. However, hepatocyte growth factor and insulin did not stimulate GPEI-mediated gene expression. On the other hand, the antioxidant reagents butylhydroxyanisole and t-butylhydroquinone, stimulated GPEI-mediated gene expression, but the level of GSTP1 mRNA was not elevated. Our observations suggest that EGF and TGF alpha induce GSTP1 by the same signal transduction pathway as PenCB. Since the sequence of GPEI is similar to that of the antioxidant responsive element (ARE), some factors which bind to ARE might play a role in GPEI-mediated gene expression.

Epidermal growth factor regulation of glutathione S-transferase gene expression in the rat is mediated by class Pi glutathione S-transferase enhancer I.

PubMed Central

Matsumoto, M; Imagawa, M; Aoki, Y

2000-01-01

Using chloramphenicol acetyltransferase assays we showed that epidermal growth factor (EGF), transforming growth factor alpha (TGF alpha), and 3,3',4,4',5-pentachlorobiphenyl (PenCB) induce class Pi glutathione S-transferase (GSTP1) in primary cultured rat liver parenchymal cells. GSTP1 enhancer I (GPEI), which is required for the stimulation of GSTP1 expression by PenCB, also mediates EGF and TGF alpha stimulation of GSTP1 gene expression. However, hepatocyte growth factor and insulin did not stimulate GPEI-mediated gene expression. On the other hand, the antioxidant reagents butylhydroxyanisole and t-butylhydroquinone, stimulated GPEI-mediated gene expression, but the level of GSTP1 mRNA was not elevated. Our observations suggest that EGF and TGF alpha induce GSTP1 by the same signal transduction pathway as PenCB. Since the sequence of GPEI is similar to that of the antioxidant responsive element (ARE), some factors which bind to ARE might play a role in GPEI-mediated gene expression. PMID:10861232

Reversing SKI-SMAD4-mediated suppression is essential for TH17 cell differentiation.

PubMed

Zhang, Song; Takaku, Motoki; Zou, Liyun; Gu, Ai-di; Chou, Wei-Chun; Zhang, Ge; Wu, Bing; Kong, Qing; Thomas, Seddon Y; Serody, Jonathan S; Chen, Xian; Xu, Xiaojiang; Wade, Paul A; Cook, Donald N; Ting, Jenny P Y; Wan, Yisong Y

2017-11-02

T helper 17 (T H 17) cells are critically involved in host defence, inflammation, and autoimmunity. Transforming growth factor β (TGFβ) is instrumental in T H 17 cell differentiation by cooperating with interleukin-6 (refs 6, 7). Yet, the mechanism by which TGFβ enables T H 17 cell differentiation remains elusive. Here we reveal that TGFβ enables T H 17 cell differentiation by reversing SKI-SMAD4-mediated suppression of the expression of the retinoic acid receptor (RAR)-related orphan receptor γt (RORγt). We found that, unlike wild-type T cells, SMAD4-deficient T cells differentiate into T H 17 cells in the absence of TGFβ signalling in a RORγt-dependent manner. Ectopic SMAD4 expression suppresses RORγt expression and T H 17 cell differentiation of SMAD4-deficient T cells. However, TGFβ neutralizes SMAD4-mediated suppression without affecting SMAD4 binding to the Rorc locus. Proteomic analysis revealed that SMAD4 interacts with SKI, a transcriptional repressor that is degraded upon TGFβ stimulation. SKI controls histone acetylation and deacetylation of the Rorc locus and T H 17 cell differentiation via SMAD4: ectopic SKI expression inhibits H3K9 acetylation of the Rorc locus, Rorc expression, and T H 17 cell differentiation in a SMAD4-dependent manner. Therefore, TGFβ-induced disruption of SKI reverses SKI-SMAD4-mediated suppression of RORγt to enable T H 17 cell differentiation. This study reveals a critical mechanism by which TGFβ controls T H 17 cell differentiation and uncovers the SKI-SMAD4 axis as a potential therapeutic target for treating T H 17-related diseases.

Eosinophilic esophagitis is characterized by a non-IgE-mediated food hypersensitivity.

PubMed

Simon, D; Cianferoni, A; Spergel, J M; Aceves, S; Holbreich, M; Venter, C; Rothenberg, M E; Terreehorst, I; Muraro, A; Lucendo, A J; Schoepfer, A; Straumann, A; Simon, H-U

2016-05-01

Eosinophilic esophagitis (EoE) is a chronic disease characterized clinically by symptoms of esophageal dysfunction and histologically by eosinophil-predominant inflammation. EoE is frequently associated with concomitant atopic diseases and immunoglobulin E (IgE) sensitization to food allergens in children as well as to aeroallergens and cross-reactive plant allergen components in adults. Patients with EoE respond well to elemental and empirical food elimination diets. Recent research has, however, indicated that the pathogenesis of EoE is distinct from IgE-mediated food allergy. In this review, we discuss the individual roles of epithelial barrier defects, dysregulated innate and adaptive immune responses, and of microbiota in the pathogenesis of EoE. Although food has been recognized as a trigger factor of EoE, the mechanism by which it initiates or facilitates eosinophilic inflammation appears to be largely independent of IgE and needs to be further investigated. Understanding the pathogenic role of food in EoE is a prerequisite for the development of specific diagnostic tools and targeted therapeutic procedures. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Altered IFN-γ-mediated immunity and transcriptional expression patterns in N-Ethyl-N-nitrosourea-induced STAT4 mutants confer susceptibility to acute typhoid-like disease.

PubMed

Eva, Megan M; Yuki, Kyoko E; Dauphinee, Shauna M; Schwartzentruber, Jeremy A; Pyzik, Michal; Paquet, Marilène; Lathrop, Mark; Majewski, Jacek; Vidal, Silvia M; Malo, Danielle

2014-01-01

Salmonella enterica is a ubiquitous Gram-negative intracellular bacterium that continues to pose a global challenge to human health. The etiology of Salmonella pathogenesis is complex and controlled by pathogen, environmental, and host genetic factors. In fact, patients immunodeficient in genes in the IL-12, IL-23/IFN-γ pathway are predisposed to invasive nontyphoidal Salmonella infection. Using a forward genomics approach by N-ethyl-N-nitrosourea (ENU) germline mutagenesis in mice, we identified the Ity14 (Immunity to Typhimurium locus 14) pedigree exhibiting increased susceptibility following in vivo Salmonella challenge. A DNA-binding domain mutation (p.G418_E445) in Stat4 (Signal Transducer and Activator of Transcription Factor 4) was the causative mutation. STAT4 signals downstream of IL-12 to mediate transcriptional regulation of inflammatory immune responses. In mutant Ity14 mice, the increased splenic and hepatic bacterial load resulted from an intrinsic defect in innate cell function, IFN-γ-mediated immunity, and disorganized granuloma formation. We further show that NK and NKT cells play an important role in mediating control of Salmonella in Stat4(Ity14/Ity14) mice. Stat4(Ity14/Ity14) mice had increased expression of genes involved in cell-cell interactions and communication, as well as increased CD11b expression on a subset of splenic myeloid dendritic cells, resulting in compromised recruitment of inflammatory cells to the spleen during Salmonella infection. Stat4(Ity14/Ity14) presented upregulated compensatory mechanisms, although inefficient and ultimately Stat4(Ity14/Ity14) mice develop fatal bacteremia. The following study further elucidates the pathophysiological impact of STAT4 during Salmonella infection.

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.

Transmembrane 4 L Six Family Member 5 (TM4SF5)-Mediated Epithelial-Mesenchymal Transition in Liver Diseases.

PubMed

Lee, Jung Weon

2015-01-01

The membrane protein TM4SF5, a member of the transmembrane 4L six family, forms a tetraspanin-enriched microdomain (TEM) on the cell surface, where many different membrane proteins and receptors form a massive protein-protein complex to regulate cellular functions including transdifferentiation, migration, and invasion. We recently reported that TM4SF5 causes epithelial-mesenchymal transition (EMT), eventually contributing to aberrant multilayer cellular growth, drug resistance, enhanced migration, invasion, its circulation in the blood, tumor initiation for successful metastasis, and muscle development in zebrafish. In this review, I summarize the information on the role of TM4SF5 in EMT-related functions at TM4SF5-enriched microdomain (T5EM) on cell surface, where proteins such as TM4SF5, CD151, CD44, integrins, and epidermal growth factor receptor (EGFR) can form numerous protein complexes. TM4SF5-mediated EMT contributes to diverse cellular functions, leading to fibrotic phenotypes and initiating and maintaining tumors in primary and/or metastatic regions, in addition to its role in muscle development in zebrafish. Anti-TM4SF5 strategies for addressing the protein networks can lead to regulation of the fibrotic, tumorigenic, and tumor-maintaining functions of TM4SF5-positive hepatic cells. This review is for us to (re)consider the antifibrotic or antitumorigenic (i.e., anti-EMT-related diseases) strategies of dealing with protein networks that would be involved in cross-talks to regulate various cellular functions during TM4SF5-dependent progression from fibrotic to cancerous hepatic cells. Copyright © 2015 Elsevier Inc. All rights reserved.

IL-9-producing cells in the development of IgE-mediated food allergy.

PubMed

Shik, Dana; Tomar, Sunil; Lee, Jee-Boong; Chen, Chun-Yu; Smith, Andrew; Wang, Yui-Hsi

2017-01-01

Food allergy is a harmful immune reaction driven by uncontrolled type 2 immune responses. Considerable evidence demonstrates the key roles of mast cells, IgE, and TH2 cytokines in mediating food allergy. However, this evidence provides limited insight into why only some, rather than all, food allergic individuals are prone to develop life-threatening anaphylaxis. Clinical observations suggest that patients sensitized to food through the skin early in life may later develop severe food allergies. Aberrant epidermal thymic stromal lymphopoietin and interleukin (IL) 33 production and genetic predisposition can initiate an allergic immune response mediated by dendritic cells and CD4 + TH2 cells in inflamed skin. After allergic sensitization, intestinal IL-25 and food ingestion enhance concerted interactions between type 2 innate lymphoid cells (ILC2s) and CD4 + TH2 cells, which perpetuate allergic reactions from the skin to the gut. IL-4 and cross-linking of antigen/IgE/FcεR complexes induce emigrated mast cell progenitors to develop into the multi-functional IL-9-producing mucosal mast cells, which produce prodigious amounts of IL-9 and mast cell mediators to drive intestinal mastocytosis in an autocrine loop. ILC2s and TH9 cells may also serve as alternative cellular sources of IL-9 to augment the amplification of intestinal mastocytosis, which is the key cellular checkpoint in developing systemic anaphylaxis. These findings provide a plausible view of how food allergy develops and progresses in a stepwise manner and that atopic signals, dietary allergen ingestion, and inflammatory cues are fundamental in promoting life-threatening anaphylaxis. This information will aid in improving diagnosis and developing more effective therapies for food allergy-triggered anaphylaxis.

Insulin modulates hippocampally-mediated spatial working memory via glucose transporter-4.

PubMed

Pearson-Leary, J; Jahagirdar, V; Sage, J; McNay, E C

2018-02-15

The insulin-regulated glucose transporter, GluT4, is a key molecule in peripheral insulin signaling. Although GluT4 is abundantly expressed in neurons of specific brain regions such as the hippocampus, the functional role of neuronal GluT4 is unclear. Here, we used pharmacological inhibition of GluT4-mediated glucose uptake to determine whether GluT4 mediates insulin-mediated glucose uptake in the hippocampus. Consistent with previous reports, we found that glucose utilization increased in the dorsal hippocampus of male rats during spontaneous alternation (SA), a hippocampally-mediated spatial working memory task. We previously showed that insulin signaling within the hippocampus is required for processing this task, and that administration of exogenous insulin enhances performance. At baseline levels of hippocampal insulin, inhibition of GluT4-mediated glucose uptake did not affect SA performance. However, inhibition of an upstream regulator of GluT4, Akt, did impair SA performance. Conversely, when a memory-enhancing dose of insulin was delivered to the hippocampus prior to SA-testing, inhibition of GluT4-mediated glucose transport prevented cognitive enhancement. These data suggest that baseline hippocampal cognitive processing does not require functional hippocampal GluT4, but that cognitive enhancement by supra-baseline insulin does. Consistent with these findings, we found that in neuronal cell culture, insulin increases glucose utilization in a GluT4-dependent manner. Collectively, these data demonstrate a key role for GluT4 in transducing the procognitive effects of elevated hippocampal insulin. Copyright © 2017 Elsevier B.V. All rights reserved.

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

Multisite Phosphorylation of Human Liver Cytochrome P450 3A4 Enhances Its gp78- and CHIP-mediated Ubiquitination

PubMed Central

Wang, YongQiang; Guan, Shenheng; Acharya, Poulomi; Liu, Yi; Thirumaran, Ranjit K.; Brandman, Relly; Schuetz, Erin G.; Burlingame, Alma L.; Correia, Maria Almira

2012-01-01

CYP3A4, an integral endoplasmic reticulum (ER)-anchored protein, is the major human liver cytochrome P450 enzyme responsible for the disposition of over 50% of clinically relevant drugs. Alterations of its protein turnover can influence drug metabolism, drug-drug interactions, and the bioavailability of chemotherapeutic drugs. Such CYP3A4 turnover occurs via a classical ER-associated degradation (ERAD) process involving ubiquitination by both UBC7/gp78 and UbcH5a/CHIP E2-E3 complexes for 26 S proteasomal targeting. These E3 ligases act sequentially and cooperatively in CYP3A4 ERAD because RNA interference knockdown of each in cultured hepatocytes results in the stabilization of a functionally active enzyme. We have documented that UBC7/gp78-mediated CYP3A4 ubiquitination requires protein phosphorylation by protein kinase (PK) A and PKC and identified three residues (Ser-478, Thr-264, and Ser-420) whose phosphorylation is required for intracellular CYP3A4 ERAD. We document herein that of these, Ser-478 plays a pivotal role in UBC7/gp78-mediated CYP3A4 ubiquitination, which is accelerated and enhanced on its mutation to the phosphomimetic Asp residue but attenuated on its Ala mutation. Intriguingly, CYP3A5, a polymorphically expressed human liver CYP3A4 isoform (containing Asp-478) is ubiquitinated but not degraded to a greater extent than CYP3A4 in HepG2 cells. This suggests that although Ser-478 phosphorylation is essential for UBC7/gp78-mediated CYP3A4 ubiquitination, it is not sufficient for its ERAD. Additionally, we now report that CYP3A4 protein phosphorylation by PKA and/or PKC at sites other than Ser-478, Thr-264, and Ser-420 also enhances UbcH5a/CHIP-mediated ubiquitination. Through proteomic analyses, we identify (i) 12 additional phosphorylation sites that may be involved in CHIP-CYP3A4 interactions and (ii) 8 previously unidentified CYP3A4 ubiquitination sites within spatially associated clusters of Asp/Glu and phosphorylatable Ser/Thr residues that may

Does Possession of Apolipoprotein E[superscript E]4 Benefit Cognitive Function in Healthy Young Adults?

ERIC Educational Resources Information Center

Bunce, David; Anstey, Kaarin J.; Burns, Richard; Christensen, Helen; Easteal, Simon

2011-01-01

There is considerable evidence that the apolipoprotein E (APOE)[superscript E]4 allele is associated with cognitive deficits in older persons, and is a risk factor for dementia. However, it has recently been suggested that possession of the [superscript E]4 allele may benefit cognition in early adulthood. We tested this possibility in 5445…

Problems analysis and new fabrication strategies of mediated electrochemical biosensors for wastewater toxicity assessment.

PubMed

Yang, Yajie; Fang, Deyu; Liu, Yanran; Liu, Runze; Wang, Xiaoshen; Yu, Yuan; Zhi, Jinfang

2018-06-15

Conventional mediated electrochemical biosensors for toxicity assessment were almost based on 'one-pot' principle, i.e., mediators and the under-test chemicals were mixed together in the same vessel. In this process, the electron mediator is assumed to be merely an electron acceptor and cannot react with under-test toxicants. Actually，some under-test pollutants (such as metal ions) could react with the electron mediators, thus affecting the detection accuracy and sensitivity of the sensors. It was also found that at least two other interference factors have been ignored in present'one-pot' mediated electrochemical biosensor systems, i.e., (1) the electrochemical sensitivity of mediators to pH; and (2) the potential reactions between under-test chemicals and buffers and the consequent pH changes. In this study, the three ignored interference factors have been investigated systematically and demonstrated by significance tests. Moreover, a solving strategy, an isolation method, is proposed for fabrication of novel mediated electrochemical biosensor to avoid the interference factors existing at present mediated electrochemical biosensor. According to the testing results obtained from the isolation method, IC 50 values of Cu 2+ , Cd 2+ , Zn 2+ , Fe 3+ , Ni 2+ and Cr 3+ were 21.3 mg/L, 3.7 mg/L, 26.7 mg/L, 4.4 mg/L and 10.7 mg/L, respectively. The detection results of four real water samples also suggested this method could be applied for the practical and complex samples. Copyright © 2018 Elsevier B.V. All rights reserved.

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

Silencing of the Wnt transcription factor TCF4 sensitizes colorectal cancer cells to (chemo-) radiotherapy

PubMed Central

Kendziorra, Emil; Ahlborn, Kerstin; Spitzner, Melanie; Rave-Fränk, Margret; Emons, Georg; Gaedcke, Jochen; Kramer, Frank; Wolff, Hendrik A.; Becker, Heinz; Beissbarth, Tim; Ebner, Reinhard; Ghadimi, B.Michael; Pukrop, Tobias; Ried, Thomas; Grade, Marian

2011-01-01

A considerable percentage of rectal cancers are resistant to standard preoperative chemoradiotherapy. Because patients with a priori-resistant tumors do not benefit from multimodal treatment, understanding and overcoming this resistance remains of utmost clinical importance. We recently reported overexpression of the Wnt transcription factor TCF4, also known as TCF7L2, in rectal cancers that were resistant to 5-fluorouracil-based chemoradiotherapy. Because Wnt signaling has not been associated with treatment response, we aimed to investigate whether TCF4 mediates chemoradioresistance. RNA interference-mediated silencing of TCF4 was employed in three colorectal cancer (CRC) cell lines, and sensitivity to (chemo-) radiotherapy was assessed using a standard colony formation assay. Silencing of TCF4 caused a significant sensitization of CRC cells to clinically relevant doses of X-rays. This effect was restricted to tumor cells with high T cell factor (TCF) reporter activity, presumably in a β-catenin-independent manner. Radiosensitization was the consequence of (i) a transcriptional deregulation of Wnt/TCF4 target genes, (ii) a silencing-induced G2/M phase arrest, (iii) an impaired ability to adequately halt cell cycle progression after radiation and (iv) a compromised DNA double strand break repair as assessed by γH2AX staining. Taken together, our results indicate a novel mechanism through which the Wnt transcription factor TCF4 mediates chemoradioresistance. Moreover, they suggest that TCF4 is a promising molecular target to sensitize resistant tumor cells to (chemo-) radiotherapy. PMID:21983179

Role of p70S6K1-mediated phosphorylation of eIF4B and PDCD4 proteins in the regulation of protein synthesis.

PubMed

Dennis, Michael D; Jefferson, Leonard S; Kimball, Scot R

2012-12-14

Modulation of mRNA binding to the 40 S ribosomal subunit during translation initiation controls not only global rates of protein synthesis but also regulates the pattern of protein expression by allowing for selective inclusion, or exclusion, of mRNAs encoding particular proteins from polysomes. The mRNA binding step is modulated by signaling through a protein kinase known as the mechanistic target of rapamycin complex 1 (mTORC1). mTORC1 directly phosphorylates the translational repressors eIF4E binding proteins (4E-BP) 1 and 2, releasing them from the mRNA cap binding protein eIF4E, thereby promoting assembly of the eIF4E·eIF4G complex. mTORC1 also phosphorylates the 70-kDa ribosomal protein S6 kinase 1 (p70S6K1), which subsequently phosphorylates eIF4B, and programmed cell death 4 (PDCD4), which sequesters eIF4A from the eIF4E·eIF4G complex, resulting in repressed translation of mRNAs with highly structured 5'-untranslated regions. In the present study, we compared the role of the 4E-BPs in the regulation of global rates of protein synthesis to that of eIF4B and PDCD4. We found that maintenance of eIF4E interaction with eIF4G was not by itself sufficient to sustain global rates of protein synthesis in the absence of mTORC1 signaling to p70S6K1; phosphorylation of both eIF4B and PDCD4 was additionally required. We also found that the interaction of eIF4E with eIF4G was maintained in the liver of fasted rats as well as in serum-deprived mouse embryo fibroblasts lacking both 4E-BP1 and 4E-BP2, suggesting that the interaction of eIF4G with eIF4E is controlled primarily through the 4E-BPs.

Identifying mediating factors of moral reasoning in science education

NASA Astrophysics Data System (ADS)

Zeidler, Dana L.; Schafer, Larry E.

The purpose of this research was to examine how science content knowledge, moral reasoning ability, attitudes, and past experiences mediate the formation of moral judgments on environmental dilemmas. The study was conducted in two phases using environmental science majors and nonscience majors of college age. Phase One determined if environmental science majors exhibited higher levels of moral reasoning on nontechnical environmental social issues than on general social issues and examined the extent to which possible mediating factors accounted for differences in moral reasoning. Phase Two was qualitative in nature, the purpose of which was to observe and identify trends in conversations between subjects as to how certain mediating factors are revealed as people form moral judgments. The framework on which this study was constructed incorporates a progressive educational position; a position that views science education as being interdisciplinary, and a social means to a social end.

Glial cell-expressed mechanosensitive channel TRPV4 mediates infrasound-induced neuronal impairment.

PubMed

Shi, Ming; Du, Fang; Liu, Yang; Li, Li; Cai, Jing; Zhang, Guo-Feng; Xu, Xiao-Fei; Lin, Tian; Cheng, Hao-Ran; Liu, Xue-Dong; Xiong, Li-Ze; Zhao, Gang

2013-11-01

Vibroacoustic disease, a progressive and systemic disease, mainly involving the central nervous system, is caused by excessive exposure to low-frequency but high-intensity noise generated by various heavy transportations and machineries. Infrasound is a type of low-frequency noise. Our previous studies demonstrated that infrasound at a certain intensity caused neuronal injury in rats but the underlying mechanism(s) is still largely unknown. Here, we showed that glial cell-expressed TRPV4, a Ca(2+)-permeable mechanosensitive channel, mediated infrasound-induced neuronal injury. Among different frequencies and intensities, infrasound at 16 Hz and 130 dB impaired rat learning and memory abilities most severely after 7-14 days exposure, a time during which a prominent loss of hippocampal CA1 neurons was evident. Infrasound also induced significant astrocytic and microglial activation in hippocampal regions following 1- to 7-day exposure, prior to neuronal apoptosis. Moreover, pharmacological inhibition of glial activation in vivo protected against neuronal apoptosis. In vitro, activated glial cell-released proinflammatory cytokines IL-1β and TNF-α were found to be key factors for this neuronal apoptosis. Importantly, infrasound induced an increase in the expression level of TRPV4 both in vivo and in vitro. Knockdown of TRPV4 expression by siRNA or pharmacological inhibition of TRPV4 in cultured glial cells decreased the levels of IL-1β and TNF-α, attenuated neuronal apoptosis, and reduced TRPV4-mediated Ca(2+) influx and NF-κB nuclear translocation. Finally, using various antagonists we revealed that calmodulin and protein kinase C signaling pathways were involved in TRPV4-triggered NF-κB activation. Thus, our results provide the first evidence that glial cell-expressed TRPV4 is a potential key factor responsible for infrasound-induced neuronal impairment.

Inflammatory mediator mRNA expression by adenovirus E1A-transfected bronchial epithelial cells.

PubMed

Higashimoto, Yuji; Elliott, W Mark; Behzad, Ali R; Sedgwick, Edward G; Takei, Tatsuo; Hogg, James C; Hayashi, Shizu

2002-07-15

Lung tissue from patients with emphysema and airway obstruction carries excess adenoviral E1A DNA that is expressed as protein in airway surface epithelium and is associated with an increased inflammatory response. To examine mechanisms by which latent adenoviral infection might amplify the inflammatory process, we transfected primary human bronchial epithelial (HBE) cells from three separate patients undergoing lung resection so that they stably expressed adenovirus E1A. Lipopolysaccharide stimulation of the E1A-transfected HBE cells increased intercellular adhesion molecule-1 and interleukin-8 mRNA and protein expression compared with control cells from the same patient. It also induced greater intercellular adhesion molecule-1 promoter activity and greater nuclear factor-kappa B binding activity of nuclear extracts in E1A transfectants than controls. E1A-positive transfectants constitutively expressed transforming growth factor-beta 1 mRNA and protein, whereas this expression was either very low or not detected in control cells. We conclude that adenoviral E1A transfection transforms primary HBE cells and upregulates their production of mediators that are clinically relevant to the pathogenesis of chronic obstructive pulmonary disease.

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

Nitric oxide mediates angiogenesis induced in vivo by platelet-activating factor and tumor necrosis factor-alpha.

PubMed Central

Montrucchio, G.; Lupia, E.; de Martino, A.; Battaglia, E.; Arese, M.; Tizzani, A.; Bussolino, F.; Camussi, G.

1997-01-01

We evaluated the role of an endogenous production of nitric oxide (NO) in the in vitro migration of endothelial cells and in the in vivo angiogenic response elicited by platelet-activating factor (PAF), tumor necrosis factor-alpha (TNF), and basic fibroblast growth factor (bFGF). The NO synthase inhibitor, N omega-nitro-L-arginine-methyl ester (L-NAME), but not its enantiomer D-NAME, prevented chemotaxis of endothelial cells induced in vitro by PAF and by TNF. The motogenic activity of TNF was also inhibited by WEB 2170, a specific PAF-receptor antagonist. In contrast, chemotaxis induced by bFGF was not prevented by L-NAME or by WEB 2170. Angiogenesis was studied in vivo in a murine model in which Matrigel was used as a vehicle for the delivery of mediators. In this model, the angiogenesis induced by PAF and TNF was inhibited by WEB 2170 and L-NAME but not by D-NAME. In contrast, angiogenesis induced by bFGF was not affected by L-NAME or by WEB 2170. TNF, but not bFGF, induced PAF synthesis within Matrigel. These results suggest that NO mediates the angiogenesis induced by PAF as well as that induced by TNF, which is dependent on the production of PAF. In contrast, the angiogenic effect of bFGF appears to be both PAF and NO independent. Images Figure 3 Figure 4 PMID:9250168

Prilocaine- and lidocaine-induced methemoglobinemia is caused by human carboxylesterase-, CYP2E1-, and CYP3A4-mediated metabolic activation.

PubMed

Higuchi, Ryota; Fukami, Tatsuki; Nakajima, Miki; Yokoi, Tsuyoshi

2013-06-01

Prilocaine and lidocaine are classified as amide-type local anesthetics for which serious adverse effects include methemoglobinemia. Although the hydrolyzed metabolites of prilocaine (o-toluidine) and lidocaine (2,6-xylidine) have been suspected to induce methemoglobinemia, the metabolic enzymes that are involved remain uncharacterized. In the present study, we aimed to identify the human enzymes that are responsible for prilocaine- and lidocaine-induced methemoglobinemia. Our experiments revealed that prilocaine was hydrolyzed by recombinant human carboxylesterase (CES) 1A and CES2, whereas lidocaine was hydrolyzed by only human CES1A. When the parent compounds (prilocaine and lidocaine) were incubated with human liver microsomes (HLM), methemoglobin (Met-Hb) formation was lower than when the hydrolyzed metabolites were incubated with HLM. In addition, Met-Hb formation when prilocaine and o-toluidine were incubated with HLM was higher than that when lidocaine and 2,6-xylidine were incubated with HLM. Incubation with diisopropyl fluorophosphate and bis-(4-nitrophenyl) phosphate, which are general inhibitors of CES, significantly decreased Met-Hb formation when prilocaine and lidocaine were incubated with HLM. An anti-CYP3A4 antibody further decreased the residual formation of Met-Hb. Met-Hb formation after the incubation of o-toluidine and 2,6-xylidine with HLM was only markedly decreased by incubation with an anti-CYP2E1 antibody. o-Toluidine and 2,6-xylidine were further metabolized by CYP2E1 to 4- and 6-hydroxy-o-toluidine and 4-hydroxy-2,6-xylidine, respectively, and these metabolites were shown to more efficiently induce Met-Hb formation than the parent compounds. Collectively, we found that the metabolites produced by human CES-, CYP2E1-, and CYP3A4-mediated metabolism were involved in prilocaine- and lidocaine-induced methemoglobinemia.

Complement Regulator Factor H Mediates a Two-step Uptake of Streptococcus pneumoniae by Human Cells*

PubMed Central

Agarwal, Vaibhav; Asmat, Tauseef M.; Luo, Shanshan; Jensch, Inga; Zipfel, Peter F.; Hammerschmidt, Sven

2010-01-01

Streptococcus pneumoniae, a human pathogen, recruits complement regulator factor H to its bacterial cell surface. The bacterial PspC protein binds Factor H via short consensus repeats (SCR) 8–11 and SCR19–20. In this study, we define how bacterially bound Factor H promotes pneumococcal adherence to and uptake by epithelial cells or human polymorphonuclear leukocytes (PMNs) via a two-step process. First, pneumococcal adherence to epithelial cells was significantly reduced by heparin and dermatan sulfate. However, none of the glycosaminoglycans affected binding of Factor H to pneumococci. Adherence of pneumococci to human epithelial cells was inhibited by monoclonal antibodies recognizing SCR19–20 of Factor H suggesting that the C-terminal glycosaminoglycan-binding region of Factor H mediates the contact between pneumococci and human cells. Blocking of the integrin CR3 receptor, i.e. CD11b and CD18, of PMNs or CR3-expressing epithelial cells reduced significantly the interaction of pneumococci with both cell types. Similarly, an additional CR3 ligand, Pra1, derived from Candida albicans, blocked the interaction of pneumococci with PMNs. Strikingly, Pra1 inhibited also pneumococcal uptake by lung epithelial cells but not adherence. In addition, invasion of Factor H-coated pneumococci required the dynamics of host-cell actin microfilaments and was affected by inhibitors of protein-tyrosine kinases and phosphatidylinositol 3-kinase. In conclusion, pneumococcal entry into host cells via Factor H is based on a two-step mechanism. The first and initial contact of Factor H-coated pneumococci is mediated by glycosaminoglycans expressed on the surface of human cells, and the second step, pneumococcal uptake, is integrin-mediated and depends on host signaling molecules such as phosphatidylinositol 3-kinase. PMID:20504767

ATF4, A Novel Mediator of the Anabolic Actions of PTH on Bone

DTIC Science & Technology

2010-07-01

increased the expression of genes known to be associated with osteoblast differentiation including osteocalcin (Ocn), bone sialoprotein (Bsp...differentiation including osteocalcin (Ocn) (2.2-fold), bone sialoprotein (Bsp) (4.2-fold), alkaline phosphatase (Alp) (3.2-fold), a1(I) collagen (Col1... sialoprotein (BSP) gene transcription is mediated through a pituitary-specific transcription factor-1 (Pit-1) motif in the rat BSP gene promoter. Matrix Biol

Cognitive resilience to apolipoprotein E ε4: contributing factors in black and white older adults.

PubMed

Kaup, Allison R; Nettiksimmons, Jasmine; Harris, Tamara B; Sink, Kaycee M; Satterfield, Suzanne; Metti, Andrea L; Ayonayon, Hilsa N; Yaffe, Kristine

2015-03-01

Apolipoprotein E (APOE) ε4 is an established risk factor for cognitive decline and the development of dementia, but other factors may help to minimize its effects. Using APOE ε4 as an indicator of high risk, we investigated factors associated with cognitive resilience among black and white older adults who are APOE ε4 carriers. Participants included 2487 community-dwelling older (aged 69-80 years at baseline) black and white adults examined at 2 community clinics in the prospective cohort Health, Aging, and Body Composition (Health ABC) study. The baseline visits occurred from May 1997 through June 1998. Our primary analytic cohort consisted of 670 APOE ε4 carriers (329 black and 341 white participants) who were free of cognitive impairment at baseline and underwent repeated cognitive testing during an 11-year follow-up (through 2008) using the Modified Mini-Mental State Examination. We stratified all analyses by race. Using the Modified Mini-Mental State Examination scores, we assessed normative cognitive change in the entire cohort (n = 2487) and classified the APOE ε4 carriers as being cognitively resilient vs nonresilient by comparing their cognitive trajectories with those of the entire cohort. We then conducted bivariate analyses and multivariable random forest and logistic regression analyses to explore factors predictive of cognitive resilience in APOE ε4 carriers. Among white APOE ε4 carriers, the strongest predictors of cognitive resilience were, in relative order of importance, no recent negative life events, a higher literacy level, advanced age, a higher educational level, and more time spent reading. Among black APOE ε4 carriers, the strongest predictors of cognitive resilience were, in relative order of importance, a higher literacy level, a higher educational level, female sex, and the absence of diabetes mellitus. In follow-up logistic regression models, higher literacy level (adjusted odds ratio [OR], 9.50 [95% CI, 2.67-60.89]), a