Enhanced TCR-induced Apoptosis in Interferon Regulatory Factor 4–deficient CD4+ Th Cells

Transcription factors of the interferon regulatory factor (IRF) family contribute to the regulation of cell proliferation and apoptosis. Here, we show that CD4+ T helper (Th) cells lacking IRF4 (IRF4−/−) are highly sensitive to apoptosis. After infection of IRF4−/− mice with the protozoan parasite Leishmania major, the lesion-draining lymph nodes developed the prototypic lymphadenopathy of wild-type mice after 4 wk, but demonstrated almost total loss of cellularity and enhanced apoptosis after 7 wk. In vitro, activation of IRF4−/− CD4+ Th cells led to greatly increased apoptosis compared with wild-type cells. Coculture of IRF4−/− and IRF4+/+ CD4+ cells did not increase survival of IRF4−/− CD4+ cells, indicating that the enhanced rate of IRF4−/− Th cell apoptosis was neither transferable nor due to lack of a cytokine. Enhanced CD4+ cell apoptosis was also observed after anti-CD95 mAb treatment, despite normal CD95 expression. Removal of endogenous cytokines, notably interleukin (IL)-4, led to increased and equally high levels of IRF4−/− and IRF4+/+ cell apoptosis, whereas the protective activity of exogenous IL-4 was reduced in IRF4−/− CD4+ cells despite normal expression of the IL-4 receptor. Therefore, IRF4 is central in protecting CD4+ cells against proapoptotic stimuli

Anaphylatoxins Activate Ca2+, Akt/PI3-Kinase, and FOXO1/FoxP3 in the Retinal Pigment Epithelium

Purpose: The retinal pigment epithelium (RPE) is a main target for complement activation in age-related macular degeneration (AMD). The anaphylatoxins C3a and C5a have been thought to mostly play a role as chemoattractants for macrophages and immune cells;here, we explore whether they trigger RPE alterations. Specifically, we investigated the RPE as a potential immunoregulatory gate, allowing for active changes in the RPE microenvironment in response to complement. Design: In vitro and in vivo analysis of signaling pathways. Methods: Individual activities of and interaction between the two anaphylatoxin receptors were tested in cultured RPE cells by fluorescence microscopy, western blot, and immunohistochemistry. Main outcome measures: Intracellular free calcium, protein phosphorylation, immunostaining of tissues/cells, and multiplex secretion assay. Results: Similar to immune cells, anaphylatoxin exposure resulted in increases in free cytosolic Ca2+, PI3-kinase/Akt activation, FoxP3 and FOXO1 phosphorylation, and cytokine/chemokine secretion. Differential responses were elicited depending on whether C3a and C5a were co-administered or applied consecutively, and response amplitudes in co-administration experiments ranged from additive to driven by C5a (C3a + C5a = C5a) or being smaller than those elicited by C3a alone (C3a + C5a < C3a). Conclusion: We suggest that this combination of integrative signaling between C3aR and C5aR helps the RPE to precisely adopt its immune regulatory function. These data further contribute to our understanding of AMD pathophysiology

In vitro interaction network of a synthetic gut bacterial community

A key challenge in microbiome research is to predict the functionality of microbial communities based on community membership and (meta)-genomic data. As central microbiota functions are determined by bacterial community networks, it is important to gain insight into the principles that govern bacteria-bacteria interactions. Here, we focused on the growth and metabolic interactions of the Oligo-Mouse-Microbiota (OMM12) synthetic bacterial community, which is increasingly used as a model system in gut microbiome research. Using a bottom-up approach, we uncovered the directionality of strain-strain interactions in mono- and pairwise co-culture experiments as well as in community batch culture. Metabolic network reconstruction in combination with metabolomics analysis of bacterial culture supernatants provided insights into the metabolic potential and activity of the individual community members. Thereby, we could show that the OMM12 interaction network is shaped by both exploitative and interference competition in vitro in nutrient-rich culture media and demonstrate how community structure can be shifted by changing the nutritional environment. In particular, Enterococcus faecalis KB1 was identified as an important driver of community composition by affecting the abundance of several other consortium members in vitro. As a result, this study gives fundamental insight into key drivers and mechanistic basis of the OMM12 interaction network in vitro, which serves as a knowledge base for future mechanistic in vivo studies

The Evolution of Ecological Diversity in Acidobacteria

Acidobacteria occur in a large variety of ecosystems worldwide and are particularly abundant and highly diverse in soils. In spite of their diversity, only few species have been characterized to date which makes Acidobacteria one of the most poorly understood phyla among the domain Bacteria. We used a culture-independent niche modeling approach to elucidate ecological adaptations and their evolution for 4,154 operational taxonomic units (OTUs) of Acidobacteria across 150 different, comprehensively characterized grassland soils in Germany. Using the relative abundances of their 16S rRNA gene transcripts, the responses of active OTUs along gradients of 41 environmental variables were modeled using hierarchical logistic regression (HOF), which allowed to determine values for optimum activity for each variable (niche optima). By linking 16S rRNA transcripts to the phylogeny of full 16S rRNA gene sequences, we could trace the evolution of the different ecological adaptations during the diversification of Acidobacteria. This approach revealed a pronounced ecological diversification even among acidobacterial sister clades. Although the evolution of habitat adaptation was mainly cladogenic, it was disrupted by recurrent events of convergent evolution that resulted in frequent habitat switching within individual clades. Our findings indicate that the high diversity of soil acidobacterial communities is largely sustained by differential habitat adaptation even at the level of closely related species. A comparison of niche optima of individual OTUs with the phenotypic properties of their cultivated representatives showed that our niche modeling approach (1) correctly predicts those physiological properties that have been determined for cultivated species of Acidobacteria but (2) also provides ample information on ecological adaptations that cannot be inferred from standard taxonomic descriptions of bacterial isolates. These novel information on specific adaptations of not-yet-cultivated Acidobacteria can therefore guide future cultivation trials and likely will increase their cultivation success

Salmonella enterica Serovar Typhimurium Exploits Inflammation to Compete with the Intestinal Microbiota

Most mucosal surfaces of the mammalian body are colonized by microbial communities (“microbiota”). A high density of commensal microbiota inhabits the intestine and shields from infection (“colonization resistance”). The virulence strategies allowing enteropathogenic bacteria to successfully compete with the microbiota and overcome colonization resistance are poorly understood. Here, we investigated manipulation of the intestinal microbiota by the enteropathogenic bacterium Salmonella enterica subspecies 1 serovar Typhimurium (S. Tm) in a mouse colitis model: we found that inflammatory host responses induced by S. Tm changed microbiota composition and suppressed its growth. In contrast to wild-type S. Tm, an avirulent invGsseD mutant failing to trigger colitis was outcompeted by the microbiota. This competitive defect was reverted if inflammation was provided concomitantly by mixed infection with wild-type S. Tm or in mice (IL10−/−, VILLIN-HACL4-CD8) with inflammatory bowel disease. Thus, inflammation is necessary and sufficient for overcoming colonization resistance. This reveals a new concept in infectious disease: in contrast to current thinking, inflammation is not always detrimental for the pathogen. Triggering the host's immune defence can shift the balance between the protective microbiota and the pathogen in favour of the pathogen

Sicherung von Dämmen, Deichen und Stauanlagen : Handbuch für Theorie und Praxis ; Vol. V - 2015

Die Universität Siegen beschäftigt sich seit über 15 Jahren wissenschaftlich und im Bereich der anwendungsorientierten Forschung mit diesem Thema und hat dazu mittlerweile fünf Symposien durchgeführt. Mit der Veröffentlichung soll die langjährige Tradition als etablierte wissenschaftliche Plattform mit einem Wissensaustausch auf europäischer Ebene fortgesetzt werden. Die Bearbeitung dieser Thematik erfolgt auf der Basis der bewährten Kooperation zwischen Geotechnik und Wasserbau an der Universität Siegen. Aktuelle Ereignisse, wie z.B. die aus England oder Australien im Februar des Jahres 2014, machen uns aber auch deutlich, dass ein absoluter Schutz gegen Extremereignisse nicht möglich ist. Sie zeigen aber auch, dass dort wo technischer Hochwasserschutz konsequent umgesetzt wurde Schäden vermieden werden konnten. Wir sind nach den Ereignissen in den vergangenen Jahren aufgefordert wissenschaftlich noch leistungsfähigere und duktilere Systeme zu entwickeln. Weiter ist die Wissenschaft in der Pflicht, die Zivile Sicherheit im Hochwasser-schutz permanent zu bewerten, zu bearbeiten und ganzheitliche-interdisziplinäre und länderübergreifende Lösungen für die Zivilgesellschaft einzufordern

Effect of inhaled budesonide/formoterol fumarate dihydrate delivered via two different devices on lung function in patients with COPD and low peak inspiratory flow

Background and aims: Low peak inspiratory flow (PIF) is common following severe exacerbations of chronic obstructive pulmonary disease (COPD). Patients with COPD and low PIF may be at risk of suboptimal delivery of inhaled therapies to the airways, especially when using devices such as dry powder inhalers (DPIs), which require greater inspiratory effort than metered dose inhalers (MDIs). We report the results from a 2-week crossover study evaluating the effects of inhaled dual therapy with budesonide/formoterol fumarate dihydrate with an MDI with a spacer versus a DPI in patients with COPD and low PIF. Methods: This randomized, open-label, two-period (each 1 week in duration) crossover efficacy and safety study included patients with severe-to-very severe COPD and PIF < 50 L/min (NCT04078126). Patients were randomized 1:1 to twice-daily budesonide/formoterol fumarate dihydrate MDI (BFF MDI) 320/10 µg with a spacer for 1 week followed by twice-daily budesonide/formoterol fumarate dihydrate DPI (BUD/FORM DPI) 320/9 µg for 1 week, or the inverse. The primary endpoint was peak change from baseline in forced expiratory volume in 1 s (FEV 1 ) within 4 h post-dose following 1 week of treatment. Other assessments included pre-dose lung function, pharmacokinetics, and safety, as assessed by adverse events. Results: The modified intention-to-treat analysis set comprised 30 patients (mean age: 66.9 years; mean baseline FEV 1 : 766 mL; mean COPD assessment test score: 22.20). Following 1 week of treatment, both BFF MDI and BUD/FORM DPI improved mean [95% confidence interval (CI)] peak FEV 1 4 h post-dose [256 (190, 322) mL and 274 (208, 340) mL, respectively]. No clinically meaningful difference between treatments was observed for any lung function endpoint. There were no unexpected safety findings. Conclusion: Dual therapy with BFF MDI and with BUD/FORM DPI led to improvements in lung function in patients with severe-to-very severe COPD and low PIF

Multiple ionization and fragmentation of CH4 in collisions with slow highly charged ions

Werner U, Siegmann B, Lebius H, Huber B, Lutz HO. Multiple ionization and fragmentation of CH4 in collisions with slow highly charged ions. In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. Nuclear Instruments &amp; Methods in Physics Research Section B - Beam Interactions with Materials and Atoms. Vol 205. ELSEVIER SCIENCE BV; 2003: 639-642.The multiple ionization and fragmentation of methane was studied in collisions with slow highly charged Xe-ions utilizing a position- and time-sensitive multi-particle detector. The coincident measurement of the momenta of correlated fragment ions allows a detailed analysis of the fragmentation kinematics and the kinetic energy release can be derived for each break-up into charged fragments. Among the observed processes the spectra for H+ + CH3+ and H-2(-) + CH2-, showed the highest sensitivity to projectile characteristics. (C) 2003 Elsevier Science B.V. All rights reserved

Multi-fragmentation of C-60 after collisions with Arz+ ions

Reinköster A, Siegmann B, Werner U, Huber BA, Lutz HO. Multi-fragmentation of C-60 after collisions with Arz+ ions. Journal of Physics B - Atomic Molecular and Optical Physics. 2002;35(24):4989-4997.We studied the fragmentation Of C-60 molecules in collisions with slow Ar+ ions (v approximate to 0.04-0.55 au) and with Arz+ ions (z = 2, 3) at somewhat higher ions velocities (v approximate to 0.3-0.95 au). The measured mass spectra show C-60(q+) (q less than or equal to 5), smaller C-60-2m(q+) fullerenes and C-60-2m(q+). + C-n(+) fission products. Special attention is devoted to the C-60 multi-fragmentation process, i.e. the breakup.of the C-60 cage into several small C-n(+) fragments (n = 1-29). Up to seven correlated small Q fragments (n = 1-5) have been observed. The muld-fragmentation pattern depends on the projectile charge. Furthermore, it varies strongly with the projectile velocity for slow ions, whereas it becomes nearly constant for faster ions. This is in accordance with recent non-adiabatic quantum molecular dynamic calculations