315 research outputs found

    Glycogen Synthase Kinase (GSK) 3β phosphorylates and protects nuclear myosin 1c from proteasome-mediated degradation to activate rDNA transcription in early G1 cells

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    Nuclear myosin 1c (NM1) mediates RNA polymerase I (pol I) transcription activation and cell cycle progression by facilitating PCAF-mediated H3K9 acetylation, but the molecular mechanism by which NM1 is regulated remains unclear. Here, we report that at early G1 the glycogen synthase kinase (GSK) 3β phosphorylates and stabilizes NM1, allowing for NM1 association with the chromatin. Genomic analysis by ChIP-Seq showed that this mechanism occurs on the rDNA as active GSK3β selectively occupies the gene. ChIP assays and transmission electron microscopy in GSK3β-/- mouse embryonic fibroblasts indicated that at G1 rRNA synthesis is suppressed due to decreased H3K9 acetylation leading to a chromatin state incompatible with transcription. We found that GSK3β directly phosphorylates the endogenous NM1 on a single serine residue (Ser-1020) located within the NM1 C-terminus. In G1 this phosphorylation event stabilizes NM1 and prevents NM1 polyubiquitination by the E3 ligase UBR5 and proteasome-mediated degradation. We conclude that GSK3β-mediated phosphorylation of NM1 is required for pol I transcription activation

    CDK1 is a synthetic lethal target for KRAS mutant tumours.

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    Activating KRAS mutations are found in approximately 20% of human cancers but no RAS-directed therapies are currently available. Here we describe a novel, robust, KRAS synthetic lethal interaction with the cyclin dependent kinase, CDK1. This was discovered using parallel siRNA screens in KRAS mutant and wild type colorectal isogenic tumour cells and subsequently validated in a genetically diverse panel of 26 colorectal and pancreatic tumour cell models. This established that the KRAS/CDK1 synthetic lethality applies in tumour cells with either amino acid position 12 (p.G12V, pG12D, p.G12S) or amino acid position 13 (p.G13D) KRAS mutations and can also be replicated in vivo in a xenograft model using a small molecule CDK1 inhibitor. Mechanistically, CDK1 inhibition caused a reduction in the S-phase fraction of KRAS mutant cells, an effect also characterised by modulation of Rb, a master control of the G1/S checkpoint. Taken together, these observations suggest that the KRAS/CDK1 interaction is a robust synthetic lethal effect worthy of further investigation

    MRI of Arterial Flow Reserve in Patients with Intermittent Claudication: Feasibility and Initial Experience

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    Objectives: The aim of this work was to develop a MRI method to determine arterial flow reserve in patients with intermittent claudication and to investigate whether this method can discriminate between patients and healthy control subjects. Methods: Ten consecutive patients with intermittent claudication and 10 healthy control subjects were included. All subjects underwent vector cardiography triggered quantitative 2D cine MR phase-contrast imaging to obtain flow waveforms of the popliteal artery at rest and during reactive hyperemia. Resting flow, maximum hyperemic flow and absolute flow reserve were determined and compared between the two groups by two independent MRI readers. Also, interreader reproducibility of flow measures was reported. Results: Resting flow was lower in patients compared to controls (4.961.6 and 11.163.2 mL/s in patients and controls, respectively (p,0.01)). Maximum hyperemic flow was 7.362.9 and 16.463.2 mL/s (p,0.01) and the absolute flow reserve was 2.461.6 and 5.361.3 mL/s (p,0.01), respectively in patients and controls. The interreader coefficient of variation was below 10 % for all measures in both patients and controls. Conclusions: Quantitative 2D MR cine phase-contrast imaging is a promising method to determine flow reserve measures in patients with peripheral arterial disease and can be helpful to discriminate patients with intermittent claudication fro

    Transcriptome profiling of rabbit parthenogenetic blastocysts developed under in vivo conditions

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    Parthenogenetic embryos are one attractive alternative as a source of embryonic stem cells, although many aspects related to the biology of parthenogenetic embryos and parthenogenetically derived cell lines still need to be elucidated. The present work was conducted to investigate the gene expression profile of rabbit parthenote embryos cultured under in vivo conditions using microarray analysis. Transcriptomic profiles indicate 2541 differentially expressed genes between parthenotes and normal in vivo fertilised blastocysts, of which 76 genes were upregulated and 16 genes downregulated in in vivo cultured parthenote blastocyst, using 3 fold-changes as a cut-off. While differentially upregulated expressed genes are related to transport and protein metabolic process, downregulated expressed genes are related to DNA and RNA binding. Using microarray data, 6 imprinted genes were identified as conserved among rabbits, humans and mice: GRB10, ATP10A, ZNF215, NDN, IMPACT and SFMBT2. We also found that 26 putative genes have at least one member of that gene family imprinted in other species. These data strengthen the view that a large fraction of genes is differentially expressed between parthenogenetic and normal embryos cultured under the same conditions and offer a new approach to the identification of imprinted genes in rabbit. © 2012 Naturil-Alfonso et al.This work was supported by Generalitat Valenciana research programme (Prometeo 2009/125). Carmen Naturil was supported by Generalitat Valenciana research programme (Prometeo 2009/125). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Naturil Alfonso, C.; Saenz De Juano Ribes, MDLD.; Peñaranda, D.; Vicente Antón, JS.; Marco Jiménez, F. (2012). Transcriptome profiling of rabbit parthenogenetic blastocysts developed under in vivo conditions. PLoS ONE. 7(12):1-11. https://doi.org/10.1371/journal.pone.0051271S111712Harness, J. V., Turovets, N. A., Seiler, M. J., Nistor, G., Altun, G., Agapova, L. S., … Keirstead, H. S. (2011). Equivalence of Conventionally-Derived and Parthenote-Derived Human Embryonic Stem Cells. PLoS ONE, 6(1), e14499. doi:10.1371/journal.pone.0014499Lu, Z., Zhu, W., Yu, Y., Jin, D., Guan, Y., Yao, R., … Zhou, Q. (2010). Derivation and long-term culture of human parthenogenetic embryonic stem cells using human foreskin feeders. Journal of Assisted Reproduction and Genetics, 27(6), 285-291. doi:10.1007/s10815-010-9408-5Koh, C. J., Delo, D. M., Lee, J. W., Siddiqui, M. M., Lanza, R. P., Soker, S., … Atala, A. (2009). Parthenogenesis-derived multipotent stem cells adapted for tissue engineering applications. Methods, 47(2), 90-97. doi:10.1016/j.ymeth.2008.08.002Vrana, K. E., Hipp, J. D., Goss, A. M., McCool, B. A., Riddle, D. R., Walker, S. J., … Cibelli, J. B. (2003). Nonhuman primate parthenogenetic stem cells. Proceedings of the National Academy of Sciences, 100(Supplement 1), 11911-11916. doi:10.1073/pnas.2034195100Chen, Z., Liu, Z., Huang, J., Amano, T., Li, C., Cao, S., … Liu, L. (2009). Birth of Parthenote Mice Directly from Parthenogenetic Embryonic Stem Cells. Stem Cells, 27(9), 2136-2145. doi:10.1002/stem.158Sritanaudomchai, H., Ma, H., Clepper, L., Gokhale, S., Bogan, R., Hennebold, J., … Mitalipov, S. (2010). Discovery of a novel imprinted gene by transcriptional analysis of parthenogenetic embryonic stem cells. Human Reproduction, 25(8), 1927-1941. doi:10.1093/humrep/deq144Fang, Z. F., Gai, H., Huang, Y. Z., Li, S. G., Chen, X. J., Shi, J. J., … Sheng, H. Z. (2006). Rabbit embryonic stem cell lines derived from fertilized, parthenogenetic or somatic cell nuclear transfer embryos. Experimental Cell Research, 312(18), 3669-3682. doi:10.1016/j.yexcr.2006.08.013Wang, S., Tang, X., Niu, Y., Chen, H., Li, B., Li, T., … Ji, W. (2007). Generation and Characterization of Rabbit Embryonic Stem Cells. Stem Cells, 25(2), 481-489. doi:10.1634/stemcells.2006-0226Piedrahita, J. A., Anderson, G. B., & BonDurant, R. H. (1990). On the isolation of embryonic stem cells: Comparative behavior of murine, porcine and ovine embryos. Theriogenology, 34(5), 879-901. doi:10.1016/0093-691x(90)90559-cNaturil-Alfonso, C., Saenz-de-Juano, M. D., Peñaranda, D. S., Vicente, J. S., & Marco-Jiménez, F. (2011). Parthenogenic blastocysts cultured under in vivo conditions exhibit proliferation and differentiation expression genes similar to those of normal embryos. Animal Reproduction Science, 127(3-4), 222-228. doi:10.1016/j.anireprosci.2011.08.005Besenfelder, U., Strouhal, C., & Brem, G. (1998). A Method for Endoscopic Embryo Collection and Transfer in the Rabbit. Journal of Veterinary Medicine Series A, 45(1-10), 577-579. doi:10.1111/j.1439-0442.1998.tb00861.xMehaisen, G. M. K., Viudes-de-Castro, M. P., Vicente, J. S., & Lavara, R. (2006). In vitro and in vivo viability of vitrified and non-vitrified embryos derived from eCG and FSH treatment in rabbit does. Theriogenology, 65(7), 1279-1291. doi:10.1016/j.theriogenology.2005.08.007Bilodeau-Goeseels, S., & Schultz, G. A. (1997). Changes in Ribosomal Ribonucleic Acid Content Within in Vitro-produced Bovine Embryos1. Biology of Reproduction, 56(5), 1323-1329. doi:10.1095/biolreprod56.5.1323Conesa, A., Gotz, S., Garcia-Gomez, J. M., Terol, J., Talon, M., & Robles, M. (2005). Blast2GO: a universal tool for annotation, visualization and analysis in functional genomics research. Bioinformatics, 21(18), 3674-3676. doi:10.1093/bioinformatics/bti610Edgar, R. (2002). Gene Expression Omnibus: NCBI gene expression and hybridization array data repository. Nucleic Acids Research, 30(1), 207-210. doi:10.1093/nar/30.1.207Weltzien, F.-A., Pasqualini, C., Vernier, P., & Dufour, S. (2005). A quantitative real-time RT-PCR assay for European eel tyrosine hydroxylase. General and Comparative Endocrinology, 142(1-2), 134-142. doi:10.1016/j.ygcen.2004.12.019Llobat, L., Marco-Jiménez, F., Peñaranda, D., Saenz-de-Juano, M., & Vicente, J. (2011). Effect of Embryonic Genotype on Reference Gene Selection for RT-qPCR Normalization. Reproduction in Domestic Animals, 47(4), 629-634. doi:10.1111/j.1439-0531.2011.01934.xLiu, N., Enkemann, S. A., Liang, P., Hersmus, R., Zanazzi, C., Huang, J., … Liu, L. (2010). Genome-wide Gene Expression Profiling Reveals Aberrant MAPK and Wnt Signaling Pathways Associated with Early Parthenogenesis. Journal of Molecular Cell Biology, 2(6), 333-344. doi:10.1093/jmcb/mjq029Abdoon, A. S., Ghanem, N., Kandil, O. M., Gad, A., Schellander, K., & Tesfaye, D. (2012). cDNA microarray analysis of gene expression in parthenotes and in vitro produced buffalo embryos. Theriogenology, 77(6), 1240-1251. doi:10.1016/j.theriogenology.2011.11.004Labrecque, R., & Sirard, M.-A. (2011). Gene expression analysis of bovine blastocysts produced by parthenogenic activation or fertilisation. Reproduction, Fertility and Development, 23(4), 591. doi:10.1071/rd10243Rizos, D., Clemente, M., Bermejo-Alvarez, P., de La Fuente, J., Lonergan, P., & Gutiérrez-Adán, A. (2008). Consequences ofIn VitroCulture Conditions on Embryo Development and Quality. Reproduction in Domestic Animals, 43, 44-50. doi:10.1111/j.1439-0531.2008.01230.xLonergan, P., Rizos, D., Kanka, J., Nemcova, L., Mbaye, A., Kingston, M., … Boland, M. (2003). Temporal sensitivity of bovine embryos to culture environment after fertilization and the implications for blastocyst quality. Reproduction, 337-346. doi:10.1530/rep.0.1260337Memili, E., & First, N. L. (2000). Zygotic and embryonic gene expression in cow: a review of timing and mechanisms of early gene expression as compared with other species. Zygote, 8(1), 87-96. doi:10.1017/s0967199400000861Latham, K. E. (2001). Embryonic genome activation. Frontiers in Bioscience, 6(3), d748-759. doi:10.2741/a639Niemann, H., & Wrenzycki, C. (2000). Alterations of expression of developmentally important genes in preimplantation bovine embryos by in vitro culture conditions: Implications for subsequent development. Theriogenology, 53(1), 21-34. doi:10.1016/s0093-691x(99)00237-xCorcoran, D., Fair, T., Park, S., Rizos, D., Patel, O. V., Smith, G. W., … Lonergan, P. (2006). Suppressed expression of genes involved in transcription and translation in in vitro compared with in vivo cultured bovine embryos. Reproduction, 131(4), 651-660. doi:10.1530/rep.1.01015Morison, I. M., Ramsay, J. P., & Spencer, H. G. (2005). A census of mammalian imprinting. Trends in Genetics, 21(8), 457-465. doi:10.1016/j.tig.2005.06.008Bischoff, S. R., Tsai, S., Hardison, N., Motsinger-Reif, A. A., Freking, B. A., Nonneman, D., … Piedrahita, J. A. (2009). Characterization of Conserved and Nonconserved Imprinted Genes in Swine1. Biology of Reproduction, 81(5), 906-920. doi:10.1095/biolreprod.109.078139Cruz-Correa, M., Zhao, R., Oveido, M., Bernabe, R. D., Lacourt, M., Cardona, A., … Giardiello, F. M. (2009). Temporal stability and age-related prevalence of loss of imprinting of the insulin-like growth factor-2 gene. Epigenetics, 4(2), 114-118. doi:10.4161/epi.4.2.7954Park, C.-H., Uh, K.-J., Mulligan, B. P., Jeung, E.-B., Hyun, S.-H., Shin, T., … Lee, C.-K. (2011). Analysis of Imprinted Gene Expression in Normal Fertilized and Uniparental Preimplantation Porcine Embryos. PLoS ONE, 6(7), e22216. doi:10.1371/journal.pone.0022216Thurston, A., Taylor, J., Gardner, J., Sinclair, K. D., & Young, L. E. (2007). Monoallelic expression of nine imprinted genes in the sheep embryo occurs after the blastocyst stage. Reproduction, 135(1), 29-40. doi:10.1530/rep-07-0211Li, Y., & Sasaki, H. (2011). Genomic imprinting in mammals: its life cycle, molecular mechanisms and reprogramming. 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    Serotonergic, brain volume and attentional correlates of trait anxiety in primates.

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    Trait anxiety is a risk factor for the development and maintenance of affective disorders, and insights into the underlying brain mechanisms are vital for improving treatment and prevention strategies. Translational studies in non-human primates, where targeted neurochemical and genetic manipulations can be made, are critical in view of their close neuroanatomical similarity to humans in brain regions implicated in trait anxiety. Thus, we characterised the serotonergic and regional brain volume correlates of trait-like anxiety in the marmoset monkey. Low- and high-anxious animals were identified by behavioral responses to a human intruder (HI) that are known to be sensitive to anxiolytic drug treatment. Extracellular serotonin levels within the amygdala were measured with in vivo microdialysis, at baseline and in response to challenge with the selective serotonin reuptake inhibitor, citalopram. Regional brain volume was assessed by structural magnetic resonance imaging. Anxious individuals showed persistent, long-term fearful responses to both a HI and a model snake, alongside sustained attention (vigilance) to novel cues in a context associated with unpredictable threat. Neurally, high-anxious marmosets showed reduced amygdala serotonin levels, and smaller volumes in a closely connected prefrontal region, the dorsal anterior cingulate cortex. These findings highlight behavioral and neural similarities between trait-like anxiety in marmosets and humans, and set the stage for further investigation of the processes contributing to vulnerability and resilience to affective disorders.This research was supported by a Medical Research Programme Grant (G0901884) from the Medical Research Council UK (MRC) to Angela Roberts, and a PhD studentship from MRC and final-term funding from Trinity College, Cambridge, UK to Yevheniia Mikheenko.This is the author accepted manuscript. The final version is available from NPG at http://www.nature.com/npp/journal/v40/n6/full/npp2014324a.htm

    ARF-BP1 as a potential therapeutic target

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    In this review, we discuss the recent identification of ARF-BP1 (also known as Mule, UREB1, E3histone, LASU1, and HectH9). ARF-BP1, a HECT domain-containing E3 ubiquitin ligase, interacts with ARF and p53. Its ubiquitin ligase activity is inhibited by ARF. Inactivation of ARF-BP1 stabilised p53 and induced apoptosis. Notably, inactivation of ARF-BP1 also caused cell growth repression in p53-null cells and breast cancer cells with mutant p53. Thus, ARF-BP1 emerges as a novel therapeutic target against cancer regardless of p53 status

    Bupropion for the treatment of apathy in Huntington's disease:A multicenter, randomised, double-blind, placebo-controlled, prospective crossover trial

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    OBJECTIVE:To evaluate the efficacy and safety of bupropion in the treatment of apathy in Huntington's disease (HD). METHODS:In this phase 2b multicentre, double-blind, placebo-controlled crossover trial, individuals with HD and clinical signs of apathy according to the Structured Clinical Interview for Apathy-Dementia (SCIA-D), but not depression (n = 40) were randomized to receive either bupropion 150/300mg or placebo daily for 10 weeks. The primary outcome parameter was a significant change of the Apathy Evaluation Scale (AES) score after ten weeks of treatment as judged by an informant (AES-I) living in close proximity with the study participant. The secondary outcome parameters included changes of 1. AES scores determined by the patient (AES-S) or the clinical investigator (AES-C), 2. psychiatric symptoms (NPI, HADS-SIS, UHDRS-Behavior), 3. cognitive performance (SDMT, Stroop, VFT, MMSE), 4. motor symptoms (UHDRS-Motor), 5. activities of daily function (TFC, UHDRS-Function), and 6. caregiver distress (NPI-D). In addition, we investigated the effect of bupropion on brain structure as well as brain responses and functional connectivity during reward processing in a gambling task using magnetic resonance imaging (MRI). RESULTS:At baseline, there were no significant treatment group differences in the clinical primary and secondary outcome parameters. At endpoint, there was no statistically significant difference between treatment groups for all clinical primary and secondary outcome variables. Study participation, irrespective of the intervention, lessened symptoms of apathy according to the informant and the clinical investigator. CONCLUSION:Bupropion does not alleviate apathy in HD. However, study participation/placebo effects were observed, which document the need for carefully controlled trials when investigating therapeutic interventions for the neuropsychiatric symptoms of HD. TRIAL REGISTRATION:ClinicalTrials.gov 01914965

    Differential clonal evolution in oesophageal cancers in response to neo-adjuvant chemotherapy

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    How chemotherapy affects carcinoma genomes is largely unknown. Here we report whole-exome and deep sequencing of 30 paired oesophageal adenocarcinomas sampled before and after neo-adjuvant chemotherapy. Most, but not all, good responders pass through genetic bottlenecks, a feature associated with higher mutation burden pre-treatment. Some poor responders pass through bottlenecks, but re-grow by the time of surgical resection, suggesting a missed therapeutic opportunity. Cancers often show major changes in driver mutation presence or frequency after treatment, owing to outgrowth persistence or loss of sub-clones, copy number changes, polyclonality and/or spatial genetic heterogeneity. Post-therapy mutation spectrum shifts are also common, particularly C>A and TT>CT changes in good responders or bottleneckers. Post-treatment samples may also acquire mutations in known cancer driver genes (for example, SF3B1, TAF1 and CCND2) that are absent from the paired pre-treatment sample. Neo-adjuvant chemotherapy can rapidly and profoundly affect the oesophageal adenocarcinoma genome. Monitoring molecular changes during treatment may be clinically useful
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