Direct effects of 2,3,7,8 tetrachlorodibenzo-p-dioxin on antigen-presenting cells and molecular signaling pathways in dendritic cells

In experimentally exposed mice, the environmental contaminant 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD) produces significant suppression of adaptive immune responses at low doses. However, the underlying biochemical and cellular mechanisms of TCDD-induced immunotoxicity have remained elusive since the identification of these effects nearly 30 years ago. Antigen-presenting cells (APC) constitute various populations of cells essential for the initiation and maintenance of adaptive immune responses, and represent a potential target of TCDD toxicity. Thus, the studies presented here address the ability of TCDD to directly affect APC. The underlying objectives of these studies focus on the investigation of molecular signaling pathways and cellular processes potentially affected by TCDD. In order to eliminate conflicting variables found in vivo, we used ex vivo and in vitro models to address these objectives. Initial studies investigated the status and behavior of the aryl hydrocarbon receptor (AhR), a transcription factor recognized as the principal mediator of TCDD-induced immunotoxic effects, in the two main APC populations, macrophages and dendritic cells (DC). The results demonstrated that both APC populations expressed AhR. However, TCDD induced binding of AhR to dioxin response elements only in macrophages, and not DC. Because TCDD has been shown to alter DC function and survival in vivo, the possibility that TCDD altered other signaling pathways was addressed. Specifically, activation of the transcription factor NF-kB/Rel, integral in DC generation and function, was found to be suppressed by TCDD. This suppression was apparently mediated by a physical association between the AhR and proteins of NF-kB/Rel. Additional studies demonstrated that TCDD enhances the maturation of DC and appears to sensitize DC to apoptosis. These data establish that TCDD directly affects DC on the molecular and cellular levels and support several potential mechanisms of TCDD-induced immunotoxicity

Formation, regulation and evolution of Caenorhabditis elegans 3'UTRs

Post-transcriptional gene regulation frequently occurs through elements in mRNA 3′ untranslated regions (UTRs)1, 2. Although crucial roles for 3′UTR-mediated gene regulation have been found in Caenorhabditis elegans3, 4, 5, most C. elegans genes have lacked annotated 3′UTRs6, 7. Here we describe a high-throughput method for reliable identification of polyadenylated RNA termini, and we apply this method, called poly(A)-position profiling by sequencing (3P-Seq), to determine C. elegans 3′UTRs. Compared to standard methods also recently applied to C. elegans UTRs8, 3P-Seq identified 8,580 additional UTRs while excluding thousands of shorter UTR isoforms that do not seem to be authentic. Analysis of this expanded and corrected data set suggested that the high A/U content of C. elegans 3′UTRs facilitated genome compaction, because the elements specifying cleavage and polyadenylation, which are A/U rich, can more readily emerge in A/U-rich regions. Indeed, 30% of the protein-coding genes have mRNAs with alternative, partially overlapping end regions that generate another 10,480 cleavage and polyadenylation sites that had gone largely unnoticed and represent potential evolutionary intermediates of progressive UTR shortening. Moreover, a third of the convergently transcribed genes use palindromic arrangements of bidirectional elements to specify UTRs with convergent overlap, which also contributes to genome compaction by eliminating regions between genes. Although nematode 3′UTRs have median length only one-sixth that of mammalian 3′UTRs, they have twice the density of conserved microRNA sites, in part because additional types of seed-complementary sites are preferentially conserved. These findings reveal the influence of cleavage and polyadenylation on the evolution of genome architecture and provide resources for studying post-transcriptional gene regulation.National Institutes of Health (U.S.) (Grant number GM067031)National Science Foundation (U.S.). Predoctural FellowshipUnited States. Dept. of Energy. Computational Science Graduate Fellowship (Krell Institute

Turbofan gas turbine engine with variable fan outlet guide vanes

A turbofan gas turbine engine includes a forward fan section with a row of fan rotor blades, a core engine, and a fan bypass duct downstream of the forward fan section and radially outwardly of the core engine. The forward fan section has only a single stage of variable fan guide vanes which are variable fan outlet guide vanes downstream of the forward fan rotor blades. An exemplary embodiment of the engine includes an afterburner downstream of the fan bypass duct between the core engine and an exhaust nozzle. The variable fan outlet guide vanes are operable to pivot from a nominal OGV position at take-off to an open OGV position at a high flight Mach Number which may be in a range of between about 2.5-4+. Struts extend radially across a radially inwardly curved portion of a flowpath of the engine between the forward fan section and the core engine

Koinonia

Leadership Spotlight FeaturesDeveloping Servant Leaders: The Tale of Two Questions, Kevin Johnson Life at the Cross Roads: Living out the Eternal in the Midst of the Temporal, Brent Ellis Leadership Process vs. Results (Regardless of Culture, Country or Gender), Rebecca Sok Leading During Times of Conflict: Lessons from the Early Church, Carl Ruby From Fiction to Fact, Benjamin Kulpa Thinking TheologicallyCharismatic Boy Meets Reformed Girl, Michael and Stephanie Santarosa Book ReviewsA Review of Integrity: The Courage to Face the Demands of Reality (by Henry Cloud), reviewed by Aaron Damiani Leadership Can Be Taught (by Sharon Daloz Parks), reviewed by Laura M. Rodeheaver FeaturesThe President\u27s Corner Editor\u27s Desk Regional Updateshttps://pillars.taylor.edu/acsd_koinonia/1011/thumbnail.jp

Microneedles for Drug Delivery via the Gastrointestinal Tract

Both patients and physicians prefer the oral route of drug delivery. The gastrointestinal (GI) tract, though, limits the bioavailability of certain therapeutics because of its protease and bacteria-rich environment as well as general pH variability from pH 1 to 7. These extreme environments make oral delivery particularly challenging for the biologic class of therapeutics. Here, we demonstrate proof-of-concept experiments in swine that microneedle-based delivery has the capacity for improved bioavailability of a biologically active macromolecule. Moreover, we show that microneedle-containing devices can be passed and excreted from the GI tract safely. These findings strongly support the success of implementation of microneedle technology for use in the GI tract.National Institutes of Health (U.S.) (Grant EB000244)National Institutes of Health (U.S.) (Grant T32DK7191-38-S1

Inhibition of p70 S6 Kinase (S6K1) Activity by A77 1726 and Its Effect on Cell Proliferation and Cell Cycle Progress

AbstractLeflunomide is a novel immunomodulatory drug prescribed for treating rheumatoid arthritis. It inhibits the activity of protein tyrosine kinases and dihydroorotate dehydrogenase, a rate-limiting enzyme in the pyrimidine nucleotide synthesis pathway. Here, we report that A77 1726, the active metabolite of leflunomide, inhibited the phosphorylation of ribosomal protein S6 and two other substrates of S6K1, insulin receptor substrate-1 and carbamoyl phosphate synthetase 2, in an A375 melanoma cell line. A77 1726 increased the phosphorylation of AKT, p70 S6 (S6K1), ERK1/2, and MEK through the feedback activation of the IGF-1 receptor–mediated signaling pathway. In vitro kinase assay revealed that leflunomide and A77 1726 inhibited S6K1 activity with IC50 values of approximately 55 and 80 μM, respectively. Exogenous uridine partially blocked A77 1726–induced inhibition of A375 cell proliferation. S6K1 knockdown led to the inhibition of A375 cell proliferation but did not potentiate the antiproliferative effect of A77 1726. A77 1726 stimulated bromodeoxyuridine incorporation in A375 cells but arrested the cell cycle in the S phase, which was reversed by addition of exogenous uridine or by MAP kinase pathway inhibitors but not by rapamycin and LY294002 (a phosphoinositide 3-kinase inhibitor). These observations suggest that A77 1726 accelerates cell cycle entry into the S phase through MAP kinase activation and that pyrimidine nucleotide depletion halts the completion of the cell cycle. Our study identified a novel molecular target of A77 1726 and showed that the inhibition of S6K1 activity was in part responsible for its antiproliferative activity. Our study also provides a novel mechanistic insight into A77 1726–induced cell cycle arrest in the S phase

ATRX loss in pediatric glioma results in epigenetic dysregulation of G2/M checkpoint maintenance and sensitivity to ATM inhibition

ATRX is a histone chaperone protein recurrently mutated in pediatric glioma. The mechanism which mediates the proliferative advantage of ATRX loss in pediatric glioma remains unexplained. Recent data revealed a distinct pattern of DNA binding sites of the ATRX protein using ChIP-seq in mouse neuronal precursor cells (mNPCs). Using the ATRX peaks identified in p53-/- mNPCs, we confirmed that ATRX binding sites were significantly enriched in gene promoters (p \u3c 0.0001) and CpG islands (p \u3c 0.0001) compared with random regions. Gene set enrichment (GSE) analysis identified that cell cycle and regulation of cell cycle were among the most significantly enriched gene sets (p=2.52e-16 and 1.61e-9, respectively). We found that ATRX loss resulted in dysfunction of G2/M checkpoint maintenance: (1) ATRX-deficient pediatric glioblastoma (GBM) cells exhibited a seven-fold increase in mitotic index at 16 hours after sub-lethal radiation, and (2) murine GBM cells with ATRX knockdown demonstrated impaired pChk1 signaling on western blot at multiple time points after radiation compared to controls (p=0.0187). Notably, the ATM signaling (pChk2) remained intact in those cells, suggesting a potential therapeutic target. ATRX-deficient mouse cells were uniquely sensitive to ATM inhibitors at 1 uM alongside 8 Gy radiation compared to controls with intact ATRX (AZD0156: p=0.0027 and AZD01390: p=0.0436). Mice intra-cranially implanted with ATRX-deficient GBM cells showed improved survival (n=10, p=0.0018) when treated with AZD0156 combined with radiation. Our findings suggest that ATRX loss in glioma results in unique sensitivity to ATM inhibition via epigenetic dysregulation of G2/M checkpoint maintenance

Ultrasound-mediated gastrointestinal drug delivery

available in PMC 2016 April 08There is a significant clinical need for rapid and efficient delivery of drugs directly to the site of diseased tissues for the treatment of gastrointestinal (GI) pathologies, in particular, Crohn’s and ulcerative colitis. However, complex therapeutic molecules cannot easily be delivered through the GI tract because of physiologic and structural barriers. We report the use of ultrasound as a modality for enhanced drug delivery to the GI tract, with an emphasis on rectal delivery. Ultrasound increased the absorption of model therapeutics inulin, hydrocortisone, and mesalamine two- to tenfold in ex vivo tissue, depending on location in the GI tract. In pigs, ultrasound induced transient cavitation with negligible heating, leading to an order of magnitude enhancement in the delivery of mesalamine, as well as successful systemic delivery of a macromolecule, insulin, with the expected hypoglycemic response. In a rodent model of chemically induced acute colitis, the addition of ultrasound to a daily mesalamine enema (compared to enema alone) resulted in superior clinical and histological scores of disease activity. In both animal models, ultrasound treatment was well tolerated and resulted in minimal tissue disruption, and in mice, there was no significant effect on histology, fecal score, or tissue inflammatory cytokine levels. The use of ultrasound to enhance GI drug delivery is safe in animals and could augment the efficacy of GI therapies and broaden the scope of agents that could be delivered locally and systemically through the GI tract for chronic conditions such as inflammatory bowel disease.United States. National Institutes of Health (EB-00351)United States. National Institutes of Health (EB-000244)United States. National Institutes of Health (CA014051)United States. National Institutes of Health (T32-DK007191-38-S1

CSF H3F3A K27M circulating tumor DNA copy number quantifies tumor growth and in vitro treatment response

https://deepblue.lib.umich.edu/bitstream/2027.42/145434/1/40478_2018_Article_580.pd