Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Counseling Online and Over the Phone: When Preclosing Questions Fail as a Closing Device
    Stommel, W. ; Molder, H. te - \ 2015
    Research on Language and Social Interaction 48 (2015)3. - ISSN 0835-1813 - p. 281 - 300.
    support - repair - chat
    In this article, we present an analysis of closings in two counseling media: online, text-based exchanges (usually referred to as “chat” sessions) and telephone calls. Previous research has found that the participant who initiated a conversation preferably also initiates its termination with a possible preclosing. Advice acknowledgments, lying in the epistemic domain of the client, are devices that may work as preclosings. However, in text-based chat clients regularly refrain from advice acknowledgment. While counselors use various practices to elicit advice acknowledgment in the context of potential advice resistance, hoaxing, and/or seemingly long pauses, these questions do not always succeed as “closing devices.” This offers an explanation for counselors’ perception of online chatting as more difficult than calling. The data are in Dutch with English translation.
    p21 Ablation in Liver Enhances DNA Damage, Cholestasis, and Carcinogenesis
    Ehedego, H. ; Boekschoten, M.V. ; Hu, W. ; Doler, C. ; Haybaeck, J. ; Gassler, N. ; Muller, M.R. ; Liedtke, C. ; Trautwein, C. - \ 2015
    Cancer Research 75 (2015)6. - ISSN 0008-5472 - p. 1144 - 1155.
    kinase inhibitor p21 - human hepatocellular-carcinoma - cell-cycle progression - rad51 overexpression - expression - p21(waf1/cip1) - mice - inflammation - regeneration - repair
    Genetic mouse studies suggest that the NF-¿B pathway regulator NEMO (also known as IKK¿) controls chronic inflammation and carcinogenesis in the liver. However, the molecular mechanisms explaining the function of NEMO are not well defined. Here, we report that overexpression of the cell-cycle regulator p21 is a critical feature of liver inflammation and carcinogenesis caused by the loss of NEMO. NEMO¿hepa mice develop chronic hepatitis characterized by increased hepatocyte apoptosis and proliferation that causes the development of fibrosis and hepatocellular carcinoma (HCC), similar to the situation in human liver disease. Having identified p21 overexpression in this model, we evaluated its role in disease progression and LPS-mediated liver injury in double mutant NEMO¿hepa/p21-/- mice. Eight-week-old NEMO¿hepa/p21-/- animals displayed accelerated liver damage that was not associated with alterations in cell-cycle progression or the inflammatory response. However, livers from NEMO¿hepa/p21-/- mice displayed more severe DNA damage that was further characterized by LPS administration correlating with higher lethality of the animals. This phenotype was attenuated by genetic ablation of the TNF receptor TNF-R1 in NEMO¿hepa/p21-/- mice, demonstrating that DNA damage is induced via TNF. One-year-old NEMO¿hepa/p21-/- mice displayed greater numbers of HCC and severe cholestasis compared with NEMO¿hepa animals. Therefore, p21 overexpression in NEMO¿hepa animals protects against DNA damage, acceleration of hepatocarcinogenesis, and cholestasis. Taken together, our findings illustrate how loss of NEMO promotes chronic liver inflammation and carcinogenesis, and they identify a novel protective role for p21 against the generation of DNA damage.
    Societal impacts of regenerative medicine: reflections on the views of orthopedic professionals
    Niemansburg, S.L. ; Tempels, T.H. ; Dhert, W.J. ; Delden, J.J. van; Bredenoord, A.L. - \ 2015
    Regenerative Medicine 10 (2015)1. - ISSN 1746-0751 - p. 17 - 24.
    intervertebral disc - ethical-issues - stem - repair
    As the amount of clinical studies in orthopedic regenerative medicine (RM) is increasing, it is time to take into account its impact on society. A total of 36 biomedical professionals working at the front row of orthopedic RM were interviewed to explore their attitudes, opinions and expectations regarding the societal impacts of RM. Professionals mainly recognized the societal impacts of counteraction of aging, prevention of disease and social justice. The 'soft' sides of these impacts were hardly mentioned. Whereas they did not perceive themselves in the position to mitigate these impacts, professionals should take up their role as actor and become involved in the societal debate. This is important as they can co-shape the societal impacts during the developmental process of technologies and thereby stimulate responsible innovation.
    Angiopoietin-like 4 Stimulates STAT3-mediated iNOS Expression and Enhances Angiogenesis to Accelerate Wound Healing in Diabetic Mice
    Chong, H.C. ; Goh, C.Q. ; Gounko, N.V. ; Luo, B. ; Wang, X. ; Kersten, A.H. - \ 2014
    Molecular Therapy 22 (2014)9. - ISSN 1525-0016 - p. 1593 - 1604.
    nitric-oxide synthase - solid human tumors - international consensus - growth-factors - foot ulcers - repair - cells - quantification - methodology - mechanisms
    Impaired wound healing is a major source of morbidity in diabetic patients. Poor outcome has, in part, been related to increased inflammation, poor angiogenesis, and deficiencies in extracellular matrix components. Despite the enormous impact of these chronic wounds, effective therapies are lacking. Here, we showed that the topical application of recombinant matricellular protein angiopoietin-like 4 (ANGPTL4) accelerated wound reepithelialization in diabetic mice, in part, by improving angiogenesis. ANGPTL4 expression is markedly elevated upon normal wound injury. In contrast, ANGPTL4 expression remains low throughout the healing period in diabetic wounds. Exogenous ANGPTL4 modulated several regulatory networks involved in cell migration, angiogenesis, and inflammation, as evidenced by an altered gene expression signature. ANGPTL4 influenced the expression profile of endothelial-specific CD31 in diabetic wounds, returning its profile to that observed in wild-type wounds. We showed ANGPTL4-induced nitric oxide production through an integrin/JAK/STAT3-mediated upregulation of inducible nitric oxide synthase (iNOS) expression in wound epithelia, thus revealing a hitherto unknown mechanism by which ANGPTL4 regulated angiogenesis via keratinocyte-to-endothelial-cell communication. These data show that the replacement of ANGPTL4 may be an effective adjunctive or new therapeutic avenue for treating poor healing wounds. The present finding also confirms that therapeutic angiogenesis remains an attractive treatment modality for diabetic wound healing.
    DNA damage in plant herbarium tissue.
    Staats, M. ; Cuenca, A. ; Richardson, J.E. ; Ginkel, R.V. ; Petersen, G. ; Seberg, O. ; Bakker, F.T. - \ 2011
    PLoS ONE 6 (2011)12. - ISSN 1932-6203 - 9 p.
    programmed cell-death - ancient dna - miscoding lesions - enzymatic amplification - specimens - repair - preservation - extraction - sequences - reveals
    Dried plant herbarium specimens are potentially a valuable source of DNA. Efforts to obtain genetic information from this source are often hindered by an inability to obtain amplifiable DNA as herbarium DNA is typically highly degraded. DNA post-mortem damage may not only reduce the number of amplifiable template molecules, but may also lead to the generation of erroneous sequence information. A qualitative and quantitative assessment of DNA post-mortem damage is essential to determine the accuracy of molecular data from herbarium specimens. In this study we present an assessment of DNA damage as miscoding lesions in herbarium specimens using 454-sequencing of amplicons derived from plastid, mitochondrial, and nuclear DNA. In addition, we assess DNA degradation as a result of strand breaks and other types of polymerase non-bypassable damage by quantitative real-time PCR. Comparing four pairs of fresh and herbarium specimens of the same individuals we quantitatively assess post-mortem DNA damage, directly after specimen preparation, as well as after long-term herbarium storage. After specimen preparation we estimate the proportion of gene copy numbers of plastid, mitochondrial, and nuclear DNA to be 2.4–3.8% of fresh control DNA and 1.0–1.3% after long-term herbarium storage, indicating that nearly all DNA damage occurs on specimen preparation. In addition, there is no evidence of preferential degradation of organelle versus nuclear genomes. Increased levels of C¿T/G¿A transitions were observed in old herbarium plastid DNA, representing 21.8% of observed miscoding lesions. We interpret this type of post-mortem DNA damage-derived modification to have arisen from the hydrolytic deamination of cytosine during long-term herbarium storage. Our results suggest that reliable sequence data can be obtained from herbarium specimens.
    The Potorous CPD Photolyase Rescues a Cryptochrome-Deficient Mammalian Circadian Clock
    Chaves, I. ; Nijman, R.M. ; Biernat, M.A. ; Bajek, M.I. ; Brand, K. ; Carvalho da Silva, A. ; Saito, S. ; Yagita, K. ; Eker, A.P.M. ; Horst, G.T.J. van der - \ 2011
    PLoS ONE 6 (2011)8. - ISSN 1932-6203 - 11 p.
    light photoreceptor family - gene-expression - peripheral clock - biological clock - dna photolyase - skin-cancer - transcription - evolution - rhythms - repair
    Despite the sequence and structural conservation between cryptochromes and photolyases, members of the cryptochrome/photolyase (flavo)protein family, their functions are divergent. Whereas photolyases are DNA repair enzymes that use visible light to lesion-specifically remove UV-induced DNA damage, cryptochromes act as photoreceptors and circadian clock proteins. To address the functional diversity of cryptochromes and photolyases, we investigated the effect of ectopically expressed Arabidopsis thaliana (6-4)PP photolyase and Potorous tridactylus CPD-photolyase (close and distant relatives of mammalian cryptochromes, respectively), on the performance of the mammalian cryptochromes in the mammalian circadian clock. Using photolyase transgenic mice, we show that Potorous CPD-photolyase affects the clock by shortening the period of behavioral rhythms. Furthermore, constitutively expressed CPD-photolyase is shown to reduce the amplitude of circadian oscillations in cultured cells and to inhibit CLOCK/BMAL1 driven transcription by interacting with CLOCK. Importantly, we show that Potorous CPD-photolyase can restore the molecular oscillator in the liver of (clock-deficient) Cry1/Cry2 double knockout mice. These data demonstrate that a photolyase can act as a true cryptochrome. These findings shed new light on the importance of the core structure of mammalian cryptochromes in relation to its function in the circadian clock and contribute to our further understanding of the evolution of the cryptochrome/photolyase protein family.
    Angiopoietin-like 4 Interacts with Matrix Proteins to Modulate Wound Healing
    Goh, Y.Y. ; Pal, M. ; Chong, H.C. ; Zhu, P. ; Tan, M.J. ; Punugu, L. ; Tan, C.K. ; Huang, R.L. ; Sze, S.K. ; Yang Tang, M.B. ; Ling Ding, J. ; Kersten, A.H. ; Tan, N.S. - \ 2010
    Journal of Biological Chemistry 285 (2010)43. - ISSN 0021-9258 - p. 32999 - 33009.
    activated receptor-beta/delta - human epidermal-keratinocytes - ppar-beta/delta - transcriptional control - cell-growth - expression - beta - migration - target - repair
    A dynamic cell-matrix interaction is crucial for a rapid cellular response to changes in the environment. Appropriate cell behavior in response to the changing wound environment is required for efficient wound closure. However, the way in which wound keratinocytes modify the wound environment to coordinate with such cellular responses remains less studied. We demonstrated that angiopoietin-like 4 (ANGPTL4) produced by wound keratinocytes coordinates cell-matrix communication. ANGPTL4 interacts with vitronectin and fibronectin in the wound bed, delaying their proteolytic degradation by metalloproteinases. This interaction does not interfere with integrin-matrix protein recognition and directly affects cell-matrix communication by altering the availability of intact matrix proteins. These interactions stimulate integrin- focal adhesion kinase, 14-3-3, and PKC-mediated signaling pathways essential for effective wound healing. The deficiency of ANGPTL4 in mice delays wound re-epithelialization. Further analysis revealed that cell migration was impaired in the ANGPTL4-deficient keratinocytes. Altogether, the findings provide molecular insight into a novel control of wound healing via ANGPTL4-dependent regulation of cell-matrix communication. Given the known role of ANGPTL4 in glucose and lipid homeostasis, it is a prime therapeutic candidate for the treatment of diabetic wounds. It also underscores the importance of cell-matrix communication during angiogenesis and cancer metastasis.
    Angiopoietin-Like 4 Interacts with Integrins ß1 and ß5 to Modulate Keratinocyte Migration
    Goh, Y.Y. ; Pal, M. ; Chong, H.C. ; Zhu, P. ; Tan, M.J. ; Punugu, L. ; Lam, C.R.I. ; Yau, Y.H. ; Tan, C.K. ; Huang, R.L. ; Tan, S. ; Yang Tang, M.B. ; Ling Ding, J. ; Kersten, A.H. ; Tan, N.S. - \ 2010
    American Journal of Pathology 177 (2010)6. - ISSN 0002-9440 - p. 2791 - 2803.
    induced adipose factor - cell-migration - alpha-6-beta-4 integrin - in-vivo - protein - kinase - expression - repair - metastasis - inhibition
    Adipose tissue secretes adipocytokines for energy homeostasis, but recent evidence indicates that some adipocytokines also have a profound local impact on wound healing. Upon skin injury, keratinocytes use various signaling molecules to promote reepithelialization for efficient wound closure. In this study, we identify a novel function of adipocytokine angiopoietin-like 4 (ANGPTL4) in keratinocytes during wound healing through the control of both integrin-mediated signaling and internalization. Using two different in vivo models based on topical immuno-neutralization of ANGPTL4 as well as ablation of the ANGPTL4 gene, we show that ANGPTL4-deficient mice exhibit delayed wound reepithelialization with impaired keratinocyte migration. Human keratinocytes in which endogenous ANGPTL4 expression was suppressed by either siRNA or a neutralizing antibody show impaired migration associated with diminished integrin-mediated signaling. Importantly, we identify integrins ß1 and ß5, but not ß3, as novel binding partners of ANGPTL4. ANGPTL4-bound integrin ß1 activated the FAK-Src-PAK1 signaling pathway, which is important for cell migration. The findings presented herein reveal an unpredicted role of ANGPTL4 during wound healing and demonstrate how ANGPTL4 stimulates intracellular signaling mechanisms to coordinate cellular behavior. Our findings provide insight into a novel cell migration control mechanism and underscore the physiological importance of the modulation of integrin activity in cancer metastasis
    DNA photolyases of Chrysodeixis chalcites nucleopolyhedrovirus are targeted to the nucleus and interact with chromosomes and mitotic spindle structures
    Xu, F. ; Vlak, J.M. ; Eker, A.P.M. ; Oers, M.M. van - \ 2010
    Journal of General Virology 91 (2010)4. - ISSN 0022-1317 - p. 907 - 914.
    cyclobutane pyrimidine dimers - induced apoptosis - rna-polymerase - baculovirus - repair - identification - photorepair - irradiation - sequence - genome
    Cyclobutane pyrimidine dimer (CPD) photolyases convert UV-induced CPDs in DNA into monomers using visible light as the energy source. Two phr genes encoding class II CPD photolyases PHR1 and PHR2 have been identified in Chrysodeixis chalcites nucleopolyhedrovirus (ChchNPV). Transient expression assays in insect cells showed that PHR1–EGFP fusion protein was localized in the nucleus. Early after transfection, PHR2–EGFP was distributed over the cytoplasm and nucleus but, over time, it became localized predominantly in the nucleus. Immunofluorescence analysis with anti-PHR2 antiserum showed that, early after transfection, non-fused PHR2 was already present mainly in the nucleus, suggesting that the fusion of PHR2 to EGFP hindered its nuclear import. Both PHR–EGFP fusion proteins strongly colocalized with chromosomes and spindle, aster and midbody structures during host-cell mitosis. When PHR2–EGFP-transfected cells were superinfected with Autographa californica multiple-nucleocapsid NPV (AcMNPV), the protein colocalized with virogenic stroma, the replication factories of baculovirus DNA. The collective data support the supposition that the PHR2 protein plays a role in baculovirus DNA repair
    Effect of oxygen tension on adult articular chondrocytes in microcarrier bioreactor culture
    Malda, J. ; Brink, P. van den; Meeuwse, P. ; Grojec, M. ; Martens, D.E. ; Tramper, J. ; Riesle, J. ; Blitterswijk, C.A. van - \ 2004
    Tissue Engineering 10 (2004)7-8. - ISSN 1076-3279 - p. 987 - 994.
    intermittent hydrostatic-pressure - human nasal chondrocytes - enhances redifferentiation - differentiated phenotype - alginate culture - in-vitro - cartilage - growth - tissue - repair
    Tissue-engineering approaches for cartilage repair hold promise for the treatment of cartilage defects. Various methods to prevent or reduce dedifferentiation during chondrocyte expansion are currently under investigation. In the present study we evaluated the effect of oxygen on chondrocyte proliferation, as oxygen has received increased attention as a possible regulator of chondrocyte differentiation and its effect during expansion is uncertain. Therefore, the effect of three oxygen tensions (4, 10.5, and 21%) was investigated in a bioreactor microcarrier culture, which allows precise control of the oxygen tension in the liquid phase. During culture cells acquired a round shape on microcarriers. No differences in proliferation rate of chondrocytes were observed within the range of oxygen tensions evaluated. Cells exhibited predominantly anaerobic metabolism and, per mole of glucose, approximately 2 mol of lactate was produced independent of oxygen tension. Cellular oxygen consumption was comparable for all bioreactor cultures. Nevertheless, specific consumption rates were relatively high (2–4 × 10–17 mol · cell–1 · s–1), in comparison with chondrocytes in cartilage (0.8–2.2 × 10–18 mol · cell–1). Subsequent cartilaginous tissue formation in pellets was not affected as qualitatively assessed by safranin-O staining. At the oxygen concentrations evaluated, no effect of oxygen tension was observed on proliferation, oxygen consumption, and yield of lactate on glucose administration. For future investigations of chondrocytes and oxygen, the bioreactor system, which allows precise control and monitoring of oxygen tension, holds promise.
    Low oxygen tension stimulates redifferentiation of dedifferentiated adult human nasal chondrocytes
    Malda, J. ; Blitterswijk, C.A. van; Geffen, M. van; Martens, D.E. ; Tramper, J. ; Riesle, J. - \ 2004
    Osteoarthritis and Cartilage 12 (2004)4. - ISSN 1063-4584 - p. 306 - 313.
    intermittent hydrostatic-pressure - articular-cartilage - in-vitro - differentiated phenotype - proteoglycan synthesis - alginate culture - epiphyseal plate - repair - expression - metabolism
    Objective: To determine the effect of dissolved oxygen tension (DO) on the redifferentiation of dedifferentiated adult human nasal septum chondrocytes cultured as pellets. Design: After isolation, human nasal chondrocytes were expanded in monolayer culture, which resulted in their dedifferentiation. Dedifferentiated cells were pelleted, transferred to a bioreactor and maintained for up to 21 days at 100% DO (21% oxygen), 25% DO (5.25% oxygen) or 5% DO (1% oxygen), which was controlled in the liquid phase. Redifferentiation was assessed by staining the extracellular matrix with safranin-O and by the immunolocalization of collagen types I, II, IX and of a fibroblast membrane marker (11-fibrau). In addition, glycosaminoglycans (GAG) and DNA content were determined spectrophotometrically. Results: In monolayer culture, cells dedifferentiated and multiplied 90- to 100-fold. Cell pellets cultured in a bioreactor under conditions of low oxygen tension (25% DO or 5% DO) stained intensely for GAGs and for collagen type II, but very weakly for collagen type I. After 14 days of culturing, cell pellets maintained at 5% DO stained more intensely for collagen IX and more weakly for 11-fibrau than did those incubated at 25% DO. After 21 days of culturing the GAG content of cell pellets maintained at 5% DO was significantly greater than that of those incubated at 25% DO. Under air-saturated conditions (100% DO), the DNA and GAG contents of cell pellets decreased with time in culture. After 21 days of culturing, both parameters were substantially lower in cell pellets maintained at 100% DO than in those incubated at low oxygen tensions. The staining signals for collagen types II and IX were much weaker, and those for the markers of dedifferentiation (collagen type I and 11-fibrau) much stronger under air-saturated conditions than at low oxygen tensions. Conclusion: These observations demonstrate that using the present set-up, low oxygen tension stimulates the redifferentiation of dedifferentiated adult human nasal chondrocytes in pellet cultures.
    Isolation, characterisation and expression patterns of a RAD51 ortholog from Pleurotus ostreatus
    Mikosch, T.S.P. ; Sonnenberg, A.S.M. ; Griensven, L.J.L.D. van - \ 2002
    Mycological Research 106 (2002)6. - ISSN 0953-7562 - p. 682 - 687.
    saccharomyces-cerevisiae - genetic-recombination - coprinus-cinereus - strand exchange - reca homologs - protein - repair - dmc1 - filament
    AB: Using degenerated primers for conserved regions of RecA homologs we have isolated a gene from Pleurotus ostreatus that shows characteristic features of RAD51 homologs. The encoded amino acid sequence of P. ostreatus RAD51 (PoRAD51) shows greatest sequence similarities with RAD51 from Coprinus cinereus (89% identity). Furthermore the genomic organisation of PoRAD51 is almost identical to that of RAD51 from C. cinereus. Northern analysis shows that the expression of PoRAD51 is found in vegetative mycelium, and fruit body tissue, and that it is expressed at elevated levels in lamellae/basidia and following DNA damage. A sporulation deficient mutant strain of P. ostreatus (ATTC 58937) showed expression patterns of the RAD51 gene that are similar those of the normal sporulating strain.
    Isolation, characterization, and expression patterns of a DMC1 homolog from the basidiomycete Pleurotus ostreatus
    Mikosch, T.S.P. ; Sonnenberg, A.S.M. ; Griensven, L.J.L.D. van - \ 2001
    Fungal Genetics and Biology 33 (2001)1. - ISSN 1087-1845 - p. 59 - 66.
    saccharomyces-cerevisiae - genetic-recombination - coprinus-cinereus - strand exchange - reca homologs - rad51 protein - yeast - sequence - filament - repair
    Here we describe the isolation of a Pleurotus ostreatus gene PoDMC1. The predicted amino acid sequence of the oyster mushroom gene is 62% identical to the yeast DMC1 and 60% identical to human DMC1. The highest degree of amino acid identity (88%), however, was shown with Coprinus CoLIM15, a DMC1 homolog recently found in Coprinus cinereus. The exact matching of sizes and positions of most introns in both basidiomycete genes underlines the close relationship between these DMC1 orthologs. The RecA homolog DMC1 from yeast and its orthologs from other species have been reported to be meiosis specific and essential for sporulation. Here we show that PoDMC1 is exclusively expressed in the lamellae/basidiospore fraction of fruit bodies and not in somatic cells of fruiting bodies or in vegetative mycelium. Furthermore, the gene is not expressed in the lamellae/basidiospore fraction of a nonsporulating mutant of P. ostreatus. Since one of the major problems in cultivating the oyster mushroom is the abundant sporulation that causes allergic reactions in man, PoDMC1 could be an important target gene in constructing sporeless Pleurotus strains
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