The effect of oxidative stress and glucocorticoids on TGF-ß1 production in airway epithelial cells

Transforming growth factor-β1 (TGF-β1) is implicated in inflammation and airway wall remodeling in inflammatory airway disease. Oxidative stress has also been implicated in the pathogenesis of inflammatory lung disorders. Reactive oxygen species (ROS), such as hydrogen peroxide (H2O2), in the airway may activate intracellular signalling cascades and transcription factors to exaggerate lung inflammation. The balance between nuclear histone acetylation/deacetylation has also been shown to be altered by oxidative stress and may further upregulate lung inflammation. The aim of this thesis was to determine whether ROS, alone or in combination with interleukin (IL)-1β can modulate TGF-β1 expression in lung epithelial cells and whether the effect was regulated by histone methylation. Stimulation of human airway epithelial cells (A549) with H2O2 or H2O2 plus IL-1β enhanced TGF-β1 mRNA and total protein expression. IL-1β and H2O2 together showed a greater than additive effect on TGF-β1 mRNA transcription, but not on the total protein level. The NF-[kappa]B-IKK2 inhibitor AS602868 suppressed IL-1β-and H2O2 plus IL-1β -induced TGF- β1 mRNA expression. NF-[Kappa]B p65 protein was also shown to be upregulated by IL-1β plus H2O2 stimulation. Chromatin immunoprecipitation (ChIP) experiments demonstrated that p65 was recruited to the [Kappa]B3 binding site on the native TGF-β1 promoter area. The upregulation of TGF-β1 mRNA by IL-β plus H2O2 could be suppressed by fluticasone propionate (FP) although to the same extent as seen with IL-1β-stimulated TGF-β1 mRNA expression. This suggests that H2O2 induced a relative steroid insensitivity. Both Suv39H1 protein level and mRNA expression were downregulated by IL-1β and H2O2 stimulation. Knockdown of Suv39H1 with siRNA transfection induced a trend towards increased TGF-ß1 mRNA expression upon stimulation with IL-1β and H2O2. Suv39H1 was shown to be recruited to glucocorticoid receptor by co-immunoprecipitation. The anti-inflammatory effect of FP was impaired under Suv39H1 knockdown which indicate that Suv39H1 may act as a corepressor of GR function. DNA methylation is also involved in epigenetic regulation of gene expression. IL-1β and H2O2 stimulation rapidly upregulated CpG methylation at specific sites in the TGF-β1 promoter as demonstrated by direct sequencing after bisulphite treatment and by methylation dependent immunoprecipitation study (MeDIP). Methylation at the ATG start start induced by IL-1β was reversed over time indicating an active demethylation. These results indicate that H2O2, acting via the NF-[Kappa]B pathway, increases TGF-ß1 mRNA production and that this is regulated by FP possibly through an effect on the histone methyltransferase, Suv39H1. DNA methylation is also involved in the regulation of IL-1β plus H2O2 induced TGF-β1 mRNA expression

Abnormal Domestic Information Disseminate on Cross-listed Nikkei 225 Index Futures from Abroad?

This study extends the GARCH with autoregressive conditional jump intensity in Generalized Error Distribution (GARJI-GED) model to identify the fundamental characteristics of Nikkei 225 index and futures. Furthermore, this study applied the Granger causality test to investigate whether an abnormal information lead and lag relationship existed for the Nikkei 225, SIMEX-Nikkei 225 and OSE-Nikkei 225. Empirical results demonstrate that Nikkei 225 index and futures show jump phenomena, implying a jump process is necessary to match statistical features in spot and futures markets. Finally, the empirical results indicated that the abnormal information of the OSE-Nikkei 225 futures contract significantly leads the one of the SIMEX- Nikkei 225 and Nikkei 225 index.

A Comparative Study on Spin-Orbit Torque Efficiencies from W/ferromagnetic and W/ferrimagnetic Heterostructures

It has been shown that W in its resistive form possesses the largest spin-Hall ratio among all heavy transition metals, which makes it a good candidate for generating efficient dampinglike spin-orbit torque (DL-SOT) acting upon adjacent ferromagnetic or ferrimagnetic (FM) layer. Here we provide a systematic study on the spin transport properties of W/FM magnetic heterostructures with the FM layer being ferromagnetic Co$_{20}$Fe$_{60}$B$_{20}$ or ferrimagnetic Co$_{63}$Tb$_{37}$ with perpendicular magnetic anisotropy. The DL-SOT efficiency $|\xi_{DL}|$, which is characterized by a current-induced hysteresis loop shift method, is found to be correlated to the microstructure of W buffer layer in both W/Co$_{20}$Fe$_{60}$B$_{20}$ and W/Co$_{63}$Tb$_{37}$ systems. Maximum values of $|\xi_{DL}|\approx 0.144$ and $|\xi_{DL}|\approx 0.116$ are achieved when the W layer is partially amorphous in the W/Co$_{20}$Fe$_{60}$B$_{20}$ and W/Co$_{63}$Tb$_{37}$ heterostructures, respectively. Our results suggest that the spin Hall effect from resistive phase of W can be utilized to effectively control both ferromagnetic and ferrimagnetic layers through a DL-SOT mechanism

Suppression of Exosomal PD-L1 Induces Systemic Anti-tumor Immunity and Memory.

PD-L1 on the surface of tumor cells binds its receptor PD-1 on effector T cells, thereby suppressing their activity. Antibody blockade of PD-L1 can activate an anti-tumor immune response leading to durable remissions in a subset of cancer patients. Here, we describe an alternative mechanism of PD-L1 activity involving its secretion in tumor-derived exosomes. Removal of exosomal PD-L1 inhibits tumor growth, even in models resistant to anti-PD-L1 antibodies. Exosomal PD-L1 from the tumor suppresses T cell activation in the draining lymph node. Systemically introduced exosomal PD-L1 rescues growth of tumors unable to secrete their own. Exposure to exosomal PD-L1-deficient tumor cells suppresses growth of wild-type tumor cells injected at a distant site, simultaneously or months later. Anti-PD-L1 antibodies work additively, not redundantly, with exosomal PD-L1 blockade to suppress tumor growth. Together, these findings show that exosomal PD-L1 represents an unexplored therapeutic target, which could overcome resistance to current antibody approaches

An online conserved SSR discovery through cross-species comparison

Simple sequence repeats (SSRs) play important roles in gene regulation and genome evolution. Although there exist several online resources for SSR mining, most of them only extract general SSR patterns without providing functional information. Here, an online search tool, CG-SSR (Comparative Genomics SSR discovery), has been developed for discovering potential functional SSRs from vertebrate genomes through cross-species comparison. In addition to revealing SSR candidates in conserved regions among various species, it also combines accurate coordinate and functional genomics information. CG-SSR is the first comprehensive and efficient online tool for conserved SSR discovery

STAT2 hypomorphic mutant mice display impaired dendritic cell development and antiviral response

Interferons (IFNs) are key regulators for both innate and adaptive immune responses. By screening ENU-mutagenized mice, we identified a pedigree- P117 which displayed impaired response to type I, but not type II, IFNs. Through inheritance test, genetic mapping and sequencing, we found a T to A point mutation in the 5' splice site of STAT2 intron 4–5, leading to cryptic splicing and frame shifting. As a result, the expression of STAT2 protein was greatly diminished in the mutant mice. Nonetheless, a trace amount of functional STAT2 protein was still detectable and was capable of inducing, though to a lesser extent, IFNα-downstream gene expressions, suggesting that P117 is a STAT2 hypomorphic mutant. The restoration of mouse or human STAT2 gene in P117 MEFs rescued the response to IFNα, suggesting that the mutation in STAT2 is most likely the cause of the phenotypes seen in the pedigree. Development of different subsets of lymphocytes appeared to be normal in the mutant mice except that the percentage and basal expression of CD86 in splenic pDC and cDC were reduced. In addition, in vitro Flt3L-dependent DC development and TLR ligand-mediated DC differentiation were also defective in mutant cells. These results suggest that STAT2 positively regulates DC development and differentiation. Interestingly, a severe impairment of antiviral state and increased susceptibility to EMCV infection were observed in the mutant MEFs and mice, respectively, suggesting that the remaining STAT2 is not sufficient to confer antiviral response. In sum, the new allele of STAT2 mutant reported here reveals a role of STAT2 for DC development and a threshold requirement for full functions of type I IFNs

Targeting EZH2 Reprograms Intratumoral Regulatory T Cells to Enhance Cancer Immunity.

Regulatory T cells (Tregs) are critical for maintaining immune homeostasis, but their presence in tumor tissues impairs anti-tumor immunity and portends poor prognoses in cancer patients. Here, we reveal a mechanism to selectively target and reprogram the function of tumor-infiltrating Tregs (TI-Tregs) by exploiting their dependency on the histone H3K27 methyltransferase enhancer of zeste homolog 2 (EZH2) in tumors. Disruption of EZH2 activity in Tregs, either pharmacologically or genetically, drove the acquisition of pro-inflammatory functions in TI-Tregs, remodeling the tumor microenvironment and enhancing the recruitment and function of CD8+ and CD4+ effector T cells that eliminate tumors. Moreover, abolishing EZH2 function in Tregs was mechanistically distinct from, more potent than, and less toxic than a generalized Treg depletion approach. This study reveals a strategy to target Tregs in cancer that mitigates autoimmunity by reprogramming their function in tumors to enhance anti-cancer immunity

Delivery of chemotherapeutic agents using drug-loaded irradiated tumor cells to treat murine ovarian tumors

<p>Abstract</p> <p>Background</p> <p>Ovarian cancer is the leading cause of death among women with gynecologic malignancies in the United States. Advanced ovarian cancers are difficult to cure with the current available chemotherapy, which has many associated systemic side effects. Doxorubicin is one such chemotherapeutic agent that can cause cardiotoxicity. Novel methods of delivering chemotherapy without significant side effects are therefore of critical need.</p> <p>Methods</p> <p>In the current study, we generated an irradiated tumor cell-based drug delivery system which uses irradiated tumor cells loaded with the chemotherapeutic drug, doxorubicin.</p> <p>Results</p> <p>We showed that incubation of murine ovarian cancer cells (MOSEC) with doxorubicin led to the intracellular uptake of the drug (MOSEC-dox cells) and the eventual death of the tumor cell. We then showed that doxorubicin loaded MOSEC-dox cells were able to deliver doxorubicin to MOSEC cells in vivo. Further characterization of the doxorubicin transfer revealed the involvement of cell contact. The irradiated form of the MOSEC-dox cells were capable of treating luciferase-expressing MOSEC tumor cells (MOSEC/luc) in C57BL/6 mice as well as in athymic nude mice resulting in improved survival compared to the non drug-loaded irradiated MOSEC cells. Furthermore, we showed that irradiated MOSEC-dox cells was more effective compared to an equivalent dose of doxorubicin in treating MOSEC/luc tumor-bearing mice.</p> <p>Conclusions</p> <p>Thus, the employment of drug-loaded irradiated tumor cells represents a potentially innovative approach for the delivery of chemotherapeutic drugs for the control of ovarian tumors.</p

Femtosecond laser treatment enhances DNA transfection efficiency in vivo

<p>Abstract</p> <p>Background</p> <p>Gene therapy with plasmid DNA is emerging as a promising strategy for the treatment of many diseases. One of the major obstacles to such therapy is the poor transfection efficiency of DNA <it>in vivo</it>.</p> <p>Methods</p> <p>In this report, we employed a very low power, near-infrared femtosecond laser technique to enhance the transfection efficiency of intradermally and intratumorally administered DNA plasmid.</p> <p>Results</p> <p>We found that femtosecond laser treatment can significantly enhance the delivery of DNA into the skin and into established tumors in mice. In addition, we found that both laser power density as well as duration of laser treatment are critical parameters for augmenting DNA transfection efficiency. The femtosecond laser technique employs a relatively unfocused laser beam that maximizes the transfected area, minimizes damage to tissue and simplifies its implementation.</p> <p>Conclusion</p> <p>This femtosecond new laser technology represents a safe and innovative technology for enhancing DNA gene transfer in vivo.</p