TNFR2 maintains adequate IL-12 production by dendritic cells in inflammatory responses by regulating endogenous TNF levels

Sepsis-induced immune reactions are reduced in TNF receptor 2 (TNFR2)-deficient mice as previously shown. In order to elucidate the underlying mechanisms, the functional integrity of myeloid cells of TNFR2-deficient mice was analyzed and compared to wild type (WT) mice. The capacity of dendritic cells to produce IL-12 was strongly impaired in TNF-deficient mice, mirroring impaired production of IL-12 by WT dendritic cells in sepsis or after LPS or TNF pre-treatment. In addition, TNFR2-deficient mice were refractory to LPS pre-treatment and also to hyper-sensitization by inactivated Propionibacterium acnes, indicating habituation to inflammatory stimuli by the immune response when TNFR2 is lacking. Constitutive expression of TNF mRNA in kidney, liver, spleen, colon and lung tissue, and the presence of soluble TNFR2 in urine of healthy WT mice supported the conclusion that TNF is continuously present in naïve mice and controlled by soluble TNFR2. In TNFR2-deficient mice endogenous TNF levels cannot be balanced and the continuous exposure to enhanced TNF levels impairs dendritic cell function. In conclusion, TNF pre-exposure suppresses secondary inflammatory reactions of myeloid cells; therefore, continuous control of endogenous TNF by soluble TNFR2 seems to be essential for the maintenance of adequate sensitivity to inflammatory stimuli

Pathways of carbon and energy metabolism of the epibiotic community associated with the deep-sea hydrothermal vent shrimp Rimicaris exoculata

© The Authors, 2011. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS One 6 (2011): e16018, doi:10.1371/journal.pone.0016018.The shrimp Rimicaris exoculata dominates the faunal biomass at many deep-sea hydrothermal vent sites at the Mid-Atlantic Ridge. In its enlarged gill chamber it harbors a specialized epibiotic bacterial community for which a nutritional role has been proposed. We analyzed specimens from the Snake Pit hydrothermal vent field on the Mid-Atlantic Ridge by complementing a 16S rRNA gene survey with the analysis of genes involved in carbon, sulfur and hydrogen metabolism. In addition to Epsilon- and Gammaproteobacteria, the epibiotic community unexpectedly also consists of Deltaproteobacteria of a single phylotype, closely related to the genus Desulfocapsa. The association of these phylogenetic groups with the shrimp was confirmed by fluorescence in situ hybridization. Based on functional gene analyses, we hypothesize that the Gamma- and Epsilonproteobacteria are capable of autotrophic growth by oxidizing reduced sulfur compounds, and that the Deltaproteobacteria are also involved in sulfur metabolism. In addition, the detection of proteobacterial hydrogenases indicates the potential for hydrogen oxidation in these communities. Interestingly, the frequency of these phylotypes in 16S rRNA gene clone libraries from the mouthparts differ from that of the inner lining of the gill chamber, indicating potential functional compartmentalization. Our data show the specific association of autotrophic bacteria with Rimicaris exoculata from the Snake Pit hydrothermal vent field, and suggest that autotrophic carbon fixation is contributing to the productivity of the epibiotic community with the reductive tricarboxylic acid cycle as one important carbon fixation pathway. This has not been considered in previous studies of carbon fixation and stable carbon isotope composition of the shrimp and its epibionts. Furthermore, the co-occurrence of sulfur-oxidizing and sulfur-reducing epibionts raises the possibility that both may be involved in the syntrophic exchange of sulfur compounds, which could increase the overall efficiency of this epibiotic community.Funding was provided through NSF grant OCE-0452333 and the Alfried Krupp Wissenschaftskolleg Greifswald, Germany (SMS), the Max Planck Society, the German Research Foundation (DFG) Cluster of Excellence at Marum, and MOMARnet (ND, JMP), and IFM-GEOMAR (MH, JFI)

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

The role of TNF receptor type 2 on myeloid cells in sepsis - functional analysis

Sepsis is a serious medical condition that is characterized by a whole-body inflammatory state and the presence of a known or suspected infection Dr. Theo Sterns reported that TNFR2 deficient mice were protected from a secondary infection during the phase of sepsis that is usually characterized as sepsis-induced immunosuppression The results shown and discussed in this work reveal several cellular phenotypes of TNFR2-/- myeloid cells and allow to draw conclusions about the function of TNFR2 in general and especially in sepsis. It was shown that CLP is required to induce iNOS mRNA expression and NO production in CD11b+ CD11c- cells upon stimulation with LPS and IFN-ү and that the lack of TNFR2 results in a reduction of both iNOS mRNA expression and NO production. This cellular phenotype was also found in other myeloid cells such as PEC and BMDC from naïve mice. BMDC were used as a cellular model for further investigations. TNFR2-/- BMDC produce reduced concentrations of IL-6 upon stimulation with LPS and IFN-ү. These findings indicate that TNFR2-signaling is required for adequate NO and IL-6 production. It turned out that missing TNFR2 decreased the proliferation in these cells leading to reduced cell yields at day 10 of the BMDC differentiation culture. In combination with data from TNFR1-/- BMDC TNFR2 expression was shown to be required for adequate proliferation. TNFR2-/- BMDC cultures showed reduced proportions of MDSC throughout the cultivation period. TNFR2-/- BMDC as well as TNFR2-/- BMDC sorted for the MDSC marker Ly6C+ Ly6G- showed reduced Arg1 mRNA expression indicating an important role of TNFR2 in the generation and function of MDSC. TNFR2 signaling seems to be essential for adequate generation of MDSC and could contribute to the suppressive functions of these cells in dampening inflammation in vivo. The hypothesis that TNFR2-/- cells ex vivo or in vitro contain a higher percentage or more activated MDSC could not be proven. TNFR2-/- BMDC cultures contained increased proportions of activated (MHCII+ CD80+ CD86+) cells at day 8 and day 10 indicating less suppression of T cell proliferation and, simultaneously, improved antigen presentation and, thus, better activation of T cells. These are strong indications for a dampening function of TNFR2 in the immune system as its presence seems to be required for the downregulation of activation molecules. Whether direct TNFR2-signaling or indirect effects via enhanced TNFR1-signaling as a consequence of the missing TNF antagonist soluble TNFR2 are responsible for the phenotypes of TNFR2-/- myeloid cells has been investigated using bone marrow chimeric mice and mixed BMDC cultures. It has been shown that the phenotypes of TNFR2-/- myeloid cells remain stable in BMDC from wildtype host mice that were reconstituted with TNFR2-/- bone marrow and, thus, generating wildtype conditions for a TNFR2-/- hematopoietic system. These phenotypes also persisted in TNFR2-/- BMDC in mixed BMDC differentiation cultures initially containing wildtype and TNFR2-/- bone marrow in equal proportions. This culture method generates equal environmental conditions for both types of BMDC. As TNFR2-/- BMDC of both bone marrow chimeric mice and mixed BMDC differentiation cultures maintained the phenotypes found for TNFR2-/- BMDC, this is a very strong indication for a missing intrinsic signaling via TNFR2 and, thus, confirms the hypothesis of an important role of direct TNFR2-signaling in the immune system. Additionally, these results reveal that reverse signaling via soluble or membrane-bound TNFR2 as ligand and membrane-bound TNF as receptor can be excluded as the reason for these phenotypes as the conditions are equal for TNFR2-/- and wildtype BMDC in mixed BMDC differentiation cultures. However, epigenetic promoter or histone modifications could also be the cause for the TNFR2-/- phenotypes described in this work since altered TNFR1-signaling in TNFR2-/- mice cannot be excluded completely as the TNF antagonist soluble TNFR2 is missing in these mice. Mouse anti-mouse TNFR2 mAB were generated and tested for binding as well as agonistic and antagonistic properties. The antibodies performed positive in ELISA and Western blot and one clone also stained TNFR2-expressing cells in FACS analysis. However, neither agonistic nor antagonistic functions could be detected in a cytotoxicity assay established to detect specific TNFR2 activation by using cells expressing the extracellular domain of TNFR2 fused to the intracellular domains of human Fas

Auslaenderkriminalitaet in Bayern eine Analyse der von 1983 bis 1990 polizeilich registrierten Kriminalitaet auslaendischer und deutscher Tatverdaechtiger

UuStB Koeln(38)-920106964 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Analysis of Bacterial Communities in the Rhizosphere of Chrysanthemum via Denaturing Gradient Gel Electrophoresis of PCR-Amplified 16S rRNA as Well as DNA Fragments Coding for 16S rRNA

The effect of developing chrysanthemum roots on the presence and activity of bacterial populations in the rhizosphere was examined by using culture-independent methods. Nucleic acids were extracted from rhizosphere soil samples associated with the bases of roots or root tips of plants harvested at different stages of development. PCR and reverse transcriptase (RT) PCR were used to amplify 16S ribosomal DNA (rDNA) and 16S rRNA, respectively, and the products were subjected to denaturing gradient gel electrophoresis (DGGE). Prominent DGGE bands were excised and sequenced to gain insight into the identities of predominantly present (PCR) and predominantly active (RT-PCR) bacterial populations. The majority of DGGE band sequences were related to bacterial genera previously associated with the rhizosphere, such as Pseudomonas, Comamonas, Variovorax, and Acetobacter, or typical of root-free soil environments, such as Bacillus and Arthrobacter. The PCR-DGGE patterns observed for bulk soil were somewhat more complex than those obtained from rhizosphere samples, and the latter contained a subset of the bands present in bulk soil. DGGE analysis of RT-PCR products detected a subset of bands visible in the rDNA-based analysis, indicating that some dominantly detected bacterial populations did not have high levels of metabolic activity. The sequences detected by the RT-PCR approach were, however, derived from a wide taxonomic range, suggesting that activity in the rhizosphere was not determined at broad taxonomic levels but rather was a strain- or species-specific phenomenon. Comparative analysis of DGGE profiles grouped all DNA-derived root tip samples together in a cluster, and within this cluster the root tip samples from young plants formed a separate subcluster. Comparison of rRNA-derived bacterial profiles showed no grouping of root tip samples versus root base samples. Rather, all profiles derived from 2-week-old plant rhizosphere soils grouped together regardless of location along the root

Exogenous TNFR2 activation protects from acute GvHD via host T reg cell expansion

Donor CD4(+) Foxp(3+) regulatory T cells (T reg cells) suppress graft-versus-host disease (GvHD) after allogeneic hematopoietic stem cell transplantation (HCT [allo-HCT]). Current clinical study protocols rely on the ex vivo expansion of donor T reg cells and their infusion in high numbers. In this study, we present a novel strategy for inhibiting GvHD that is based on the in vivo expansion of recipient T reg cells before allo-HCT, exploiting the crucial role of tumor necrosis factor receptor 2 (TNFR2) in T reg cell biology. Expanding radiation-resistant host T reg cells in recipient mice using a mouse TNFR2-selective agonist before allo-HCT significantly prolonged survival and reduced GvHD severity in a TNFR2-and T reg cell-dependent manner. The beneficial effects of transplanted T cells against leukemia cells and infectious pathogens remained unaffected. A corresponding human TNFR2-specific agonist expanded human T reg cells in vitro. These observations indicate the potential of our strategy to protect allo-HCT patients from acute GvHD by expanding T reg cells via selective TNFR2 activation in vivo