Antimalarial drug artemether inhibits neuroinflammation in BV2 microglia through Nrf2-dependent mechanisms

Artemether, a lipid-soluble derivative of artemisinin has been reported to possess anti-inflammatory properties. In this study, we have investigated the molecular mechanisms involved in the inhibition of neuroinflammation by the drug. The effects of artemether on neuroinflammation-mediated HT22 neuronal toxicity were also investigated in a BV2 microglia/HT22 neuron co-culture. To investigate effects on neuroinflammation, we used LPS-stimulated BV2 microglia treated with artemether (5-40µM) for 24 hours. ELISAs and western blotting were used to detect pro inflammatory cytokines, nitric oxide, PGE2, iNOS, COX-2 and mPGES-1. BACE-1 activity and Aβ levels were measured with ELISA kits. Protein levels of targets in NF-kappaB and p38 MAPK signalling, as well as HO-1, NQO1 and Nrf2 were also measured with western blot. NF-kappaB binding to the DNA was investigated using EMSA. MTT, DNA fragmentation and ROS assays in BV2-HT22 neuronal co-culture were used to evaluate the effects of artemether on neuroinflammation-induced neuronal death. The role of Nrf2 in the anti-inflammatory activity of artemether was investigated in BV2 cells transfected with Nrf2 siRNA. Artemether significantly suppressed pro-inflammatory mediators (NO/iNOS, PGE2/COX-2/mPGES-1, TNFα, and IL-6), Aβ and BACE-1 in BV2 cells following LPS stimulation. These effects of artemether were shown to be mediated through inhibition of NF-kappaB and p38MAPK signalling. Artemether produced increased levels of HO-1, NQO1 and GSH in BV2 microglia. The drug activated Nrf2 activity by increasing nuclear translocation of Nrf2 and its binding to antioxidant response elements in BV2 cells. Transfection of BV2 microglia with Nrf2 siRNA resulted in the loss of both anti-inflammatory and neuroprotective activities of artemether. We conclude that artemether induces Nrf2 expression and suggest that Nrf2 mediates the anti-inflammatory effect of artemether in BV2 microglia. Our results suggest that this drug has a therapeutic potential in neurodegenerative disorders

Mathematical model of a telomerase transcriptional regulatory network developed by cell-based screening: analysis of inhibitor effects and telomerase expression mechanisms

Cancer cells depend on transcription of telomerase reverse transcriptase (TERT). Many transcription factors affect TERT, though regulation occurs in context of a broader network. Network effects on telomerase regulation have not been investigated, though deeper understanding of TERT transcription requires a systems view. However, control over individual interactions in complex networks is not easily achievable. Mathematical modelling provides an attractive approach for analysis of complex systems and some models may prove useful in systems pharmacology approaches to drug discovery. In this report, we used transfection screening to test interactions among 14 TERT regulatory transcription factors and their respective promoters in ovarian cancer cells. The results were used to generate a network model of TERT transcription and to implement a dynamic Boolean model whose steady states were analysed. Modelled effects of signal transduction inhibitors successfully predicted TERT repression by Src-family inhibitor SU6656 and lack of repression by ERK inhibitor FR180204, results confirmed by RT-QPCR analysis of endogenous TERT expression in treated cells. Modelled effects of GSK3 inhibitor 6-bromoindirubin-3′-oxime (BIO) predicted unstable TERT repression dependent on noise and expression of JUN, corresponding with observations from a previous study. MYC expression is critical in TERT activation in the model, consistent with its well known function in endogenous TERT regulation. Loss of MYC caused complete TERT suppression in our model, substantially rescued only by co-suppression of AR. Interestingly expression was easily rescued under modelled Ets-factor gain of function, as occurs in TERT promoter mutation. RNAi targeting AR, JUN, MXD1, SP3, or TP53, showed that AR suppression does rescue endogenous TERT expression following MYC knockdown in these cells and SP3 or TP53 siRNA also cause partial recovery. The model therefore successfully predicted several aspects of TERT regulation including previously unknown mechanisms. An extrapolation suggests that a dominant stimulatory system may programme TERT for transcriptional stability

Recessed deposition of TiN into N-doped carbon as a cathode host for superior Li-S batteries performance

The final publication is available at Elsevier via https://dx.doi.org/10.1016/j.nanoen.2018.09.034 © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/In this work, we put forward a novel cathode host for Li-S batteries by loading titanium nitride (TiN) nanoparticles into the pores of N-doped carbon as a proof-of-concept. The selection of TiN arises from its strong binding ability with polysulfide and its exceptionally high conductivity of 5 × 106 S/m. As for N-doped porous carbon, it provides necessary physical adsorption and extra chemical adsorption sites from the N-doping. Besides the above advantages, the most substantial merit endowed to this structure is the pore-loaded TiN design. The carbon pore size confines the TiN precursors to the nanoscale and prevents otherwise subsequent agglomeration of TiN nanoparticles. Moreover, the pore-loaded TiN design, with fully exposed adsorptive surface and highly dispersed adsorptive sites, guards against the blocking of future sulfur infiltration and Li+ diffusion. The advantages of the TiN loaded N-doped carbon are finally confirmed by electrochemical evaluations. The capacity is found up to be 1338 mAh/g at a current density of 0.2 C and 690 mAh/g at a current density of 5 C (where 1 C = 1672 mAh/g). For durability evaluations, the capacity is maintained at 700 mAh/g after 800 cycles with a mere decay of 0.04% per cycle. Lastly, the feasibility of a high mass loading with 7 mg/cm2 is demonstrated.Natural Sciences and Engineering Research Council of CanadaWaterloo Institute for NanotechnologyCanadian Center for Electron Microscop

Intercultural influences on managing African employees of Chinese firms in Africa: Chinese managers’ HRM practices

The present paper addresses the important inter-organizational relationship between Chinese firms and local unions by investigating Chinese managers’ HRM practices in managing African employees. We utilize the storytelling research method to obtain a nuanced understanding of this little-understood, yet important phenomenon. Our data was collected through in-depth narrative interviews with 32 Chinese managers (both senior and middle) with three to eight years of professional experience in African countries from 21 Chinese firms (both state-owned and privately owned). We found that Chinese managers’ crossvergence HRM practices are a blend of divergent local contextual factors and convergent cultural factors. Our findings reveal that the cultural proximity between African “Ubuntu” and Chinese Confucianism can significantly influence Chinese firm-local union inter-organizational relationship in managing African employees of Chinese firms. The crossvergence of Chinese managers’ HRM practices can gradually affect the work behaviors of African employees over time. The paper identifies importance of the cross-cultural training and mutual learning between Chinese managers and African employees to enhance mutual understanding against the backdrop of Chinese firms entering Africa countries. Our study contributes to the better understanding of HRM practices of emerging market multinational corporations, and has important practical implications for managing African employees

Transfer of molecular recognition information from DNA nanostructures to gold nanoparticles

DNA nanotechnology offers unparalleled precision and programmability for the bottom-up organization of materials. This approach relies on pre-assembling a DNA scaffold, typically containing hundreds of different strands, and using it to position functional components. A particularly attractive strategy is to employ DNA nanostructures not as permanent scaffolds, but as transient, reusable templates to transfer essential information to other materials. To our knowledge, this approach, akin to top-down lithography, has not been examined. Here we report a molecular printing strategy that chemically transfers a discrete pattern of DNA strands from a three-dimensional DNA structure to a gold nanoparticle. We show that the particles inherit the DNA sequence configuration encoded in the parent template with high fidelity. This provides control over the number of DNA strands and their relative placement, directionality and sequence asymmetry. Importantly, the nanoparticles produced exhibit the site-specific addressability of DNA nanostructures, and are promising components for energy, information and biomedical applications

Update on HER-2 as a target for cancer therapy: The ERBB2 promoter and its exploitation for cancer treatment

Overexpression of the ERBB2 proto-oncogene is associated with amplification of the gene in breast cancer but increased activity of the promoter also plays a significant role. Members of two transcription factor families (AP-2 and Ets) show increased binding to the promoter in over-expressing cells. Consequently, strategies have been devised to target promoter activity, either through the DNA binding sites for these factors, or through another promoter sequence, a polypurine-polypyrimidine repeat structure. The promoter has also been exploited for its tumour-specific activity to direct the accumulation of cytotoxic compounds selectively within cancer cells. Our current understanding of the ERBB2 promoter is reviewed and the status of these therapeutic avenues is discussed

Facilitating functional annotation of chicken microarray data

<p>Abstract</p> <p>Background</p> <p>Modeling results from chicken microarray studies is challenging for researchers due to little functional annotation associated with these arrays. The Affymetrix GenChip chicken genome array, one of the biggest arrays that serve as a key research tool for the study of chicken functional genomics, is among the few arrays that link gene products to Gene Ontology (GO). However the GO annotation data presented by Affymetrix is incomplete, for example, they do not show references linked to manually annotated functions. In addition, there is no tool that facilitates microarray researchers to directly retrieve functional annotations for their datasets from the annotated arrays. This costs researchers amount of time in searching multiple GO databases for functional information.</p> <p>Results</p> <p>We have improved the breadth of functional annotations of the gene products associated with probesets on the Affymetrix chicken genome array by 45% and the quality of annotation by 14%. We have also identified the most significant diseases and disorders, different types of genes, and known drug targets represented on Affymetrix chicken genome array. To facilitate functional annotation of other arrays and microarray experimental datasets we developed an Array GO Mapper (<it>AGOM</it>) tool to help researchers to quickly retrieve corresponding functional information for their dataset.</p> <p>Conclusion</p> <p>Results from this study will directly facilitate annotation of other chicken arrays and microarray experimental datasets. Researchers will be able to quickly model their microarray dataset into more reliable biological functional information by using <it>AGOM </it>tool. The disease, disorders, gene types and drug targets revealed in the study will allow researchers to learn more about how genes function in complex biological systems and may lead to new drug discovery and development of therapies. The GO annotation data generated will be available for public use via AgBase website and will be updated on regular basis.</p

CD28 Costimulation Regulates Genome-Wide Effects on Alternative Splicing

CD28 is the major costimulatory receptor required for activation of naïve T cells, yet CD28 costimulation affects the expression level of surprisingly few genes over those altered by TCR stimulation alone. Alternate splicing of genes adds diversity to the proteome and contributes to tissue-specific regulation of genes. Here we demonstrate that CD28 costimulation leads to major changes in alternative splicing during activation of naïve T cells, beyond the effects of TCR alone. CD28 costimulation affected many more genes through modulation of alternate splicing than by modulation of transcription. Different families of biological processes are over-represented among genes alternatively spliced in response to CD28 costimulation compared to those genes whose transcription is altered, suggesting that alternative splicing regulates distinct biological effects. Moreover, genes dependent upon hnRNPLL, a global regulator of splicing in activated T cells, were enriched in T cells activated through TCR plus CD28 as compared to TCR alone. We show that hnRNPLL expression is dependent on CD28 signaling, providing a mechanism by which CD28 can regulate splicing in T cells and insight into how hnRNPLL can influence signal-induced alternative splicing in T cells. The effects of CD28 on alternative splicing provide a newly appreciated means by which CD28 can regulate T cell responses

Epigenomic profiling of primary gastric adenocarcinoma reveals super-enhancer heterogeneity

Regulatory enhancer elements in solid tumours remain poorly characterized. Here we apply micro-scale chromatin profiling to survey the distal enhancer landscape of primary gastric adenocarcinoma (GC), a leading cause of global cancer mortality. Integrating 110 epigenomic profiles from primary GCs, normal gastric tissues and cell lines, we highlight 36,973 predicted enhancers and 3,759 predicted super-enhancers respectively. Cell-line-defined super-enhancers can be subclassified by their somatic alteration status into somatic gain, loss and unaltered categories, each displaying distinct epigenetic, transcriptional and pathway enrichments. Somatic gain super-enhancers are associated with complex chromatin interaction profiles, expression patterns correlated with patient outcome and dense co-occupancy of the transcription factors CDX2 and HNF4α. Somatic super-enhancers are also enriched in genetic risk SNPs associated with cancer predisposition. Our results reveal a genome-wide reprogramming of the GC enhancer and super-enhancer landscape during tumorigenesis, contributing to dysregulated local and regional cancer gene expression