150 research outputs found

    Understanding teachers' approaches to assessment and restorative justice in education Newfoundland and Labrador

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    This study explores the relationship between future and current educators’ approaches to classroom assessment and their restorative justice in education practices in Newfoundland and Labrador. A two-phase triangulation mixed method research design was used in this study to explore the educators’ (both teacher candidates and classroom teachers) approaches to classroom assessment and restorative justice in education. In Phase 1, a survey was distributed to educators (n= 83) to explore their approaches and, in Phase 2, in-depth semi-structured interviews were used (n=7) to deeply explore their approaches to classroom assessment and restorative justice in education. The results of this study showed that (a) teacher candidates’ and classroom teachers’ approaches to classroom assessment and restorative justice in education were not statistically significantly different between groups, (b) teacher candidates’ and classroom teachers’ understanding of the relationship between classroom assessment restorative justice in education were quite different, and (c) both teacher candidates and classroom teachers believed they lacked sufficient knowledge about restorative justice in education, but did not hold similar beliefs regarding classroom assessment. Findings of this study serve to inform the development of teacher education programs, professional development opportunities, and educational policies in Newfoundland and Labrador

    Whole Genome Sequencing of Turkish Genomes Reveals Functional Private Alleles and Impact of Genetic Interactions with Europe, Asia and Africa

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    Background Turkey is a crossroads of major population movements throughout history and has been a hotspot of cultural interactions. Several studies have investigated the complex population history of Turkey through a limited set of genetic markers. However, to date, there have been no studies to assess the genetic variation at the whole genome level using whole genome sequencing. Here, we present whole genome sequences of 16 Turkish individuals resequenced at high coverage (32 × -48×). Results We show that the genetic variation of the contemporary Turkish population clusters with South European populations, as expected, but also shows signatures of relatively recent contribution from ancestral East Asian populations. In addition, we document a significant enrichment of non-synonymous private alleles, consistent with recent observations in European populations. A number of variants associated with skin color and total cholesterol levels show frequency differentiation between the Turkish populations and European populations. Furthermore, we have analyzed the 17q21.31 inversion polymorphism region (MAPT locus) and found increased allele frequency of 31.25% for H1/H2 inversion polymorphism when compared to European populations that show about 25% of allele frequency. Conclusion This study provides the first map of common genetic variation from 16 western Asian individuals and thus helps fill an important geographical gap in analyzing natural human variation and human migration. Our data will help develop population-specific experimental designs for studies investigating disease associations and demographic history in Turkey

    The Nlrp3 inflammasome is critical for aluminium hydroxide-mediated IL-1β secretion but dispensable for adjuvant activity

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    Aluminum hydroxide (alum) is the most widely used adjuvant in human vaccines, but the immune mechanisms that are activated by alum remain poorly understood. Alum has recently been shown to promote caspase-1 activation and IL-1β secretion, but the cellular pathways involved remain elusive. Here we report that the release of IL-1β triggered by alum is abrogated in macrophages deficient in the NLR family, pyrin domain containing 3 (Nlrp3) protein and the apoptosis-associated speck-like protein containing a caspase recruitment domain (Asc) but not the NLR family, CARD domain containing 4 (Nlrc4) protein. The requirement of the Nlrp3 inflammasome was specific for IL-1β in that secretion of TNF-α was independent of Nlrp3 or Asc. Consistently, processing of pro-caspase-1 induced by alum was abolished in macrophages lacking Nlrp3 or Asc. Unlike caspase-1 processing and IL-1β secretion triggered by LPS, alum-mediated activation of the inflammasome did not require exogenous ATP. Importantly, induction of IgG production against human serum albumin by alum was unimpaired in mice deficient in Nlrp3. These results indicate that alum induces IL-1β via the Nlrp3 inflammasome but this activity is dispensable for alum-mediated adjuvant activity. See accompanying article: http://dx.doi.org/10.1002/eji.200838648Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/60465/1/2085_ftp.pd

    The Combination of TRAIL Treatment and Cancer Cell Selective Expression of TRAIL-Death Receptor DR4 Induces Cell Death in TRAIL-Resistant Cancer Cells

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    The human telomerase reverse transcriptase (hTERT) promoter can be used for the tumor-specific expression of transgenes in order to induce selective cancer cell death. The hTERT core promoter is active in cancer cells but not in normal cells. To examine whether the combination of TNF-related apoptosis inducing ligand (TRAIL) treatment and cancer cell-selective expression of the TRAIL-death receptor could induce cell death in TRAIL-resistant cancer cells, we generated a death receptor-4 (DR4)-expressing adenovirus (Ad-hTERT-DR4), in which the expression of DR4 is driven by the hTERT promoter. Upon infection, DR4 expression was slightly increased in cancer cell lines, and cell death was observed in TRAIL-resistant cancer cell lines but not in normal human cells when DR4 infection was combined with TRAIL treatment. We also generated an adenovirus that expresses a secretable isoleucine zipper (ILZ)-fused, extracellular portion of TRAIL (Ad-ILZ-TRAIL). In cells infected with Ad-ILZ-TRAIL, TRAIL was expressed, secreted, oligomerized and biologically active in the induction of apoptosis in TRAIL-sensitive cancer cells. When Ad-hTERT-DR4 infected TRAIL-resistant HCE4 cells and Ad-ILZ-TRAIL infected TRAIL-resistant HCE7 cells were co-cultured, cell deaths were evident 24 h after co-culture. Taken together, our results reveal that the combination of TRAIL and cancer cell-specific expression of DR4 has the potential to overcome the resistance of cancer cells to TRAIL without inducing significant cell death in normal cells

    Histone deacetylase inhibitors strongly sensitise neuroblastoma cells to TRAIL-induced apoptosis by a caspases-dependent increase of the pro- to anti-apoptotic proteins ratio

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    BACKGROUND: Neuroblastoma (NB) is the second most common solid childhood tumour, an aggressive disease for which new therapeutic strategies are strongly needed. Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) selectively induces apoptosis in most tumour cells, but not in normal tissues and therefore represents a valuable candidate in apoptosis-inducing therapies. Caspase-8 is silenced in a subset of highly malignant NB cells, which results in full TRAIL resistance. In addition, despite constitutive caspase-8 expression, or its possible restoration by different strategies, NB cells remain weakly sensitive to TRAIL indicating a need to develop strategies to sensitise NB cells to TRAIL. Histone deacetylase inhibitors (HDACIs) are a new class of anti-cancer agent inducing apoptosis or cell cycle arrest in tumour cells with very low toxicity toward normal cells. Although HDACIs were recently shown to increase death induced by TRAIL in weakly TRAIL-sensitive tumour cells, the precise involved sensitisation mechanisms have not been fully identified. METHODS: NB cell lines were treated with various doses of HDACIs and TRAIL, then cytotoxicity was analysed by MTS/PMS proliferation assays, apoptosis was measured by the Propidium staining method, caspases activity by colorimetric protease assays, and (in)activation of apoptotic proteins by immunoblotting. RESULTS: Sub-toxic doses of HDACIs strongly sensitised caspase-8 positive NB cell lines to TRAIL induced apoptosis in a caspases dependent manner. Combined treatments increased the activation of caspases and Bid, and the inactivation of the anti-apoptotic proteins XIAP, Bcl-x, RIP, and survivin, thereby increasing the pro- to anti-apoptotic protein ratio. It also enhanced the activation of the mitochondrial pathway. Interestingly, the kinetics of caspases activation and inactivation of anti-apoptotic proteins is accelerated by combined treatment with TRAIL and HDACIs compared to TRAIL alone. In contrast, cell surface expression of TRAIL-receptors or TRAIL is not affected by sub-toxic doses of HDACIs. CONCLUSION: HDACIs were shown to activate the mitochondrial pathway and to sensitise NB cells to TRAIL by enhancing the amplitude of the apoptotic cascade and by restoring an apoptosis-prone ratio of pro- to anti-apoptotic proteins. Combining HDACIs and TRAIL could therefore represent a weakly toxic and promising strategy to target TRAIL-resistant tumours such as neuroblastomas

    TLR2 Signaling Contributes to Rapid Inflammasome Activation during F. novicida Infection

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    Early detection of microorganisms by the innate immune system is provided by surface-expressed and endosomal pattern recognition receptors (PRRs) such as Toll-like receptors (TLRs). Detection of microbial components by TLRs initiates a signaling cascade leading to the expression of proinflammatory cytokines including IL-6 and IL-1β. Some intracellular bacteria subvert the TLR response by rapidly escaping the phagosome and entering the cytosol. However, these bacteria may be recognized by the inflammasome, a multi-protein complex comprised of a sensor protein, ASC and the cysteine protease caspase-1. Inflammasome activation leads to release of the proinflammatory cytokines IL-1β and IL-18 and death of the infected cell, an important host defense that eliminates the pathogen's replicative niche. While TLRs and inflammasomes are critical for controlling bacterial infections, it is unknown whether these distinct host pathways cooperate to activate defenses against intracellular bacteria.Using the intracellular bacterium Francisella novicida as a model, we show that TLR2(-/-) macrophages exhibited delayed inflammasome activation compared to wild-type macrophages as measured by inflammasome assembly, caspase-1 activation, cell death and IL-18 release. TLR2 also contributed to inflammasome activation in response to infection by the cytosolic bacterium Listeria monocytogenes. Components of the TLR2 signaling pathway, MyD88 and NF-κB, were required for rapid inflammasome activation. Furthermore, TLR2(-/-) mice exhibited lower levels of cell death, caspase-1 activation, and IL-18 production than wild-type mice upon F. novicida infection.These results show that TLR2 is required for rapid inflammasome activation in response to infection by cytosolic bacterial pathogens. In addition to further characterizing the role of TLR2 in host defense, these findings broaden our understanding of how the host integrates signals from spatiotemporally separated PRRs to coordinate an innate response against intracellular bacteria

    Decitabine immunosensitizes human gliomas to NY-ESO-1 specific T lymphocyte targeting through the Fas/Fas Ligand pathway

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    <p>Abstract</p> <p>Background</p> <p>The lack of effective treatments for gliomas makes them a significant health problem and highlights the need for the development of novel and innovative treatment approaches. Immunotherapy is an appealing strategy because of the potential ability for immune cells to traffic to and destroy infiltrating tumor cells. However, the absence of well-characterized, highly immunogenic tumor-rejection antigens (TRA) in gliomas has limited the implementation of targeted immune-based therapies.</p> <p>Methods</p> <p>We hypothesized that treatment with the demethylating agent, decitabine, would upregulate the expression of TRA on tumor cells, thereby facilitating enhanced surveillance by TRA-specific T cells.</p> <p>Results and Discussion</p> <p>Treatment of human glioma cells with decitabine increased the expression of NY-ESO-1 and other well characterized cancer testes antigens. The upregulation of NY-ESO-1 made these tumors susceptible to NY-ESO-1-specific T-cell recognition and lysis. Interestingly, decitabine treatment of T98 glioma cells also sensitized them to Fas-dependent apoptosis with an agonistic antibody, while a Fas blocking antibody could largely prevent the enhanced functional recognition by NY-ESO-1 specific T cells. Thus, decitabine treatment transformed a non-immunogenic glioma cell into an immunogenic target that was efficiently recognized by NY-ESO-1--specific T cells.</p> <p>Conclusions</p> <p>Such data supports the hypothesis that agents which alter epigenetic cellular processes may "immunosensitize" tumor cells to tumor-specific T cell-mediated lysis.</p

    Differential modulation of the TRAIL receptors and the CD95 receptor in colon carcinoma cell lines

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    Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) and CD95 ligand (CD95L) are potent inducers of apoptosis in various tumour cell types. Death receptors DR4 and DR5 can induce and decoy receptors DcR1 and DcR2 can inhibit TRAIL-mediated apoptosis. The study aim was to investigate whether anticancer agents can modulate similarly TRAIL-receptor and CD95 membrane expression and TRAIL and CD95L sensitivity.Three colon carcinoma cell lines (Caco-2, Colo320 and SW948) were treated with 5-fluorouracil (5-FU), cisplatin or interferon-γ. TRAIL-receptor and CD95 membrane expression was determined flow cytometrically. Sensitivity to TRAIL or CD95L agonistic anti-CD95 antibody was determined with cytotoxicity and apoptosis assays. SW948 showed highest TRAIL sensitivity. The protein synthesis inhibitor cycloheximide decreased FLICE-like inhibitory protein levels in all cell lines, and the TRAIL-resistant cell lines Caco-2 and Colo320 became sensitive for TRAIL. Exposure of the cell lines to 5-FU, cisplatin and interferon-γ left TRAIL-receptor membrane expression and TRAIL sensitivity unaffected. CD95 membrane expression and anti-CD95 sensitivity was, however, modulated by the same drugs in all lines. Cisplatin and interferon-γ raised CD95 membrane levels 6–8-fold, interferon-γ also increased anti-CD95 sensitivity. These results indicate that the CD95 and TRAIL pathways use different mechanisms to respond to various anticancer agents. Induced CD95 membrane upregulation was associated with increased anti-CD95 sensitivity, whereas no upregulation of TRAIL-receptor membrane expression or TRAIL sensitisation could be established. For optimal use of TRAIL-mediated apoptosis for cancer therapy in certain tumours, downregulation of intracellular inhibiting factors may be required
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