Ontogeny-Driven rDNA Rearrangement, Methylation, and Transcription, and Paternal Influence

Gene rearrangement occurs during development in some cell types and this genome dynamics is modulated by intrinsic and extrinsic factors, including growth stimulants and nutrients. This raises a possibility that such structural change in the genome and its subsequent epigenetic modifications may also take place during mammalian ontogeny, a process undergoing finely orchestrated cell division and differentiation. We tested this hypothesis by comparing single nucleotide polymorphism-defined haplotype frequencies and DNA methylation of the rDNA multicopy gene between two mouse ontogenic stages and among three adult tissues of individual mice. Possible influences to the genetic and epigenetic dynamics by paternal exposures were also examined for Cr(III) and acid saline extrinsic factors. Variables derived from litters, individuals, and duplicate assays in large mouse populations were examined using linear mixed-effects model. We report here that active rDNA rearrangement, represented by changes of haplotype frequencies, arises during ontogenic progression from day 8 embryos to 6-week adult mice as well as in different tissue lineages and is modifiable by paternal exposures. The rDNA methylation levels were also altered in concordance with this ontogenic progression and were associated with rDNA haplotypes. Sperm showed highest level of methylation, followed by lungs and livers, and preferentially selected haplotypes that are positively associated with methylation. Livers, maintaining lower levels of rDNA methylation compared with lungs, expressed more rRNA transcript. In vitro transcription demonstrated haplotype-dependent rRNA expression. Thus, the genome is also dynamic during mammalian ontogeny and its rearrangement may trigger epigenetic changes and subsequent transcriptional controls, that are further influenced by paternal exposures

CD4+ T Cell Help Selectively Enhances High-Avidity Tumor Antigen-Specific CD8+ T Cells

Maintaining antitumor immunity remains a persistent impediment to cancer immunotherapy. We and others have previously reported that high-avidity CD8(+) T cells are more susceptible to tolerance induction in the tumor microenvironment. In the present study, we used a novel model where T cells derived from two independent TCR transgenic mouse lines recognize the same melanoma antigenic epitope but differ in their avidity. We tested whether providing CD4(+) T cell help would improve T cell responsiveness as a function of effector T cell avidity. Interestingly, delivery of CD4(+) T cell help during in vitro priming of CD8(+) T cells improved cytokine secretion and lytic capacity of high-avidity T cells, but not low-avidity T cells. Consistent with this observation, copriming with CD4(+) T cells improved antitumor immunity mediated by higher avidity, melanoma-specific CD8(+) T cells, but not T cells with similar specificity but lower avidity. Enhanced tumor immunity was associated with improved CD8(+) T cell expansion and reduced tolerization, and it was dependent on presentation of both CD4(+) and CD8(+) T cell epitopes by the same dendritic cell population. Our findings demonstrate that CD4(+) T cell help preferentially augments high-avidity CD8(+) T cells and provide important insight for understanding the requirements to elicit and maintain durable tumor immunity

The tumour suppressor C/EBPδ inhibits FBXW7 expression and promotes mammary tumour metastasis

This paper reveals a tumour-promoting function of the candidate tumour suppressor CCAAT/enhancer-binding protein-δ. Identification of F-box and WD repeat-domain containing 7 protein as CCAAT/enhancer-binding protein-δ target links hypoxic inflammation and tumour metastasis via mammalian target of rapamycin-mediated hypoxia-inducible factor-1α stabilization

Interferon-dependent IL-10 production by Tregs limits tumor Th17 inflammation

The capacity of IL-10 and Tregs in the inflammatory tumor microenvironment to impair anticancer Th1 immunity makes them attractive targets for cancer immunotherapy. IL-10 and Tregs also suppress Th17 activity, which is associated with poor prognosis in several cancers. However, previous studies have overlooked their potential contribution to the regulation of pathogenic cancer-associated inflammation. In this study, we investigated the origin and function of IL-10–producing cells in the tumor microenvironment using transplantable tumor models in mice. The majority of tumor-associated IL-10 was produced by an activated Treg population. IL-10 production by Tregs was required to restrain Th17-type inflammation. Accumulation of activated IL-10(+) Tregs in the tumor required type I IFN signaling but not inflammatory signaling pathways that depend on TLR adapter protein MyD88 or IL-12 family cytokines. IL-10 production limited Th17 cell numbers in both spleen and tumor. However, type I IFN was required to limit Th17 cells specifically in the tumor microenvironment, reflecting selective control of tumor-associated Tregs by type I IFN. Thus, the interplay of type I IFN, Tregs, and IL-10 is required to negatively regulate Th17 inflammation in the tumor microenvironment. Therapeutic interference of this network could therefore have the undesirable consequence of promoting Th17 inflammation and cancer growth

Regulation of the DC response to β-glucan by the IL-1-induced nuclear factor IκB-ζ.

<p>(A) Human monocyte-derived DCs were cultured with or without particulate β-glucan and/or IL-1RA (25 µg/ml). Gene expression data are from the experiment of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0114516#pone-0114516-g004" target="_blank">Figure 4A</a> and results shown are normalized mRNA counts from technical triplicates from one representative donor out of 8 analyzed. (B) Human monocyte-derived DCs were cultured for 12 h in the indicated condition. IL-1RA was used at 250 µg/ml. Total extracts were analyzed by Western blotting with the indicated antibodies. Data shown are from one representative donor out of 9 tested. Arrows indicate specific bands, while asterisks show nonspecific bands. (C) Human monocyte-derived DCs were cultured in the presence or absence of particulate β-glucan and/or IL-1RA as indicated for 6 h and nuclear extracts prepared for Western blotting. Data are from one donor and are representative of those obtained in at least 3 independent experiments with cells from different donors. Arrows indicate specific bands, while asterisks nonspecific bands. (D) Human monocyte-derived DCs from different donors were stimulated for 12 h with β-glucan in presence of transfection reagent (none) after pre-incubation with a non-targeting siRNA pool (ctr siRNA) or a pool of four siRNA directed against <i>NFKBIZ</i> (<i>NFBIZ</i> siRNA). mRNA levels in cell lysates for 64 selected genes were quantitated by NanoString's nCounter technology and the map shows genes with significant changes in expression (FDR<0.1) following knockdown of <i>NFKBIZ</i>. Results are expressed as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0114516#pone-0114516-g003" target="_blank">Figure 3</a>.</p