TCR and CD28 activate the transcription factor NF-κB in T-cells via distinct adaptor signaling complexes.

The transcription factor NF-κB is needed for the induction of inflammatory responses in T-cells. Whether its activation by the antigen-receptor and CD28 is mediated by the same or different intracellular signaling pathways has been unclear. Here, using T-cells from various knock-out (Cd28(-/-), adap(-/-)) and knock-in (i.e. Cd28 Y-170F) mice in conjunction with transfected Jurkat T-cells, we show that the TCR and CD28 use distinct pathways to activate NF-κB in T-cells. Anti-CD28 ligation alone activated NF-κB in primary and Jurkat T-cells as measured by NF-κB reporter and EMSA assays. Anti-CD28 also activated NF-κB normally in primary T-cells from adap(-/-) mice, while anti-CD3 stimulation required the adaptor ADAP. Over-expression of ADAP or its binding partner SKAP1 failed to enhance anti-CD28 activation of NF-κB, while ADAP greatly increased anti-CD3 induced NF-κB activity. By contrast, CD28 activation of NF-κB depended on GRB-2 binding to CD28 as seen in CD28 deficient Jurkat T-cells reconstituted with the CD28 YMN-FM mutant, and in primary T-cells from CD28 Y170F mutant knock-in mice. CD28 associated with GRB-2, and GRB-2 siRNA impaired CD28 NF-κB activation. GRB-2 binding partner and guanine nucleotide exchange factor, VAV1, greatly enhanced anti-CD28 driven activation of NF-κB. Further, unlike in the case of anti-CD28, NF-κB activation by anti-CD3 and its cooperation with ADAP was strictly dependent on LAT expression. Overall, we provide evidence that CD28 and the TCR complex regulate NF-κB via different signaling modules of GRB-2/VAV1 and LAT/ADAP pathways respectively.This work was supported by Wellcome Trust Progam Grant (PG) PKAG/504 to Principal Research Fellow (PRF) C.E. Rudd. We are grateful to Oreste Ocuto and Enzo Cerundolo from University of Oxford for providing CHC17 and 1G4 (Cd28−/−) Jurkat cells.This paper was originally published in Immunology Letters (Thaker YR, Schneider H, Rudd CE, Immunology Letters 2015, 163, 1, 113–119, doi:10.1016/j.imlet.2014.10.020)

The Immune Adaptor SLP-76 Binds to SUMO-RANGAP1 at Nuclear Pore Complex Filaments to Regulate Nuclear Import of Transcription Factors in T Cells

While immune cell adaptors regulate proximal T cell signaling, direct regulation of the nuclear pore complex (NPC) has not been reported. NPC has cytoplasmic filaments composed of RanGAP1 and RanBP2 with the potential to interact with cytoplasmic mediators. Here, we show that the immune cell adaptor SLP-76 binds directly to SUMO-RanGAP1 of cytoplasmic fibrils of the NPC, and that this interaction is needed for optimal NFATc1 and NF-κB p65 nuclear entry in T cells. Transmission electron microscopy showed anti-SLP-76 cytoplasmic labeling of the majority of NPCs in anti-CD3 activated T cells. Further, SUMO-RanGAP1 bound to the N-terminal lysine 56 of SLP-76 where the interaction was needed for optimal RanGAP1-NPC localization and GAP exchange activity. While the SLP-76-RanGAP1 (K56E) mutant had no effect on proximal signaling, it impaired NF-ATc1 and p65/RelA nuclear entry and in vivo responses to OVA peptide. Overall, we have identified SLP-76 as a direct regulator of nuclear pore function in T cells

How Do Persons with Young and Late Onset Dementia Die?

Background: End of life symptoms and symptom management as well as the quality of dying (QoD) of persons with advanced dementia (PWAD) have not yet been systematically studied in Germany. Objective: 1) To investigate symptoms, treatment and care at the end of life, advance care planning, and circumstances of death of recently deceased PWAD;2) To determine whether there are differences between young and late onset dementia (YOD and LOD). Methods: The study was performed in the context of the project EPYLOGE (IssuEs in Palliative care for persons in advanced and terminal stages of Young-onset and Late-Onset dementia in Germany). Closest relatives of recently deceased patients with advanced YOD (N = 46) and LOD (N = 54) living at home or in long term care were interviewed. Results: Circumstances of death, symptoms, and treatment appeared to be similar between YOD and LOD, except that persons with LOD had significantly more somatic comorbidities and were admitted to hospital in the last three months of life more often than persons with LOD. At end of life, 60% of PWAD appeared to be at peace. Difficulty swallowing, gurgling, shortness of breath, and discomfort were observed most frequently. Large interindividual differences in suffering and QoD were present. Determinants of QoD were not identified. Conclusion: Our findings suggest that low QoD was caused by inadequate recognition and/or insufficient treatment of burdensome physical and emotional symptoms. PWADs' needs should be assessed regularly, and strategies focusing on treatment and implementing support for both the patient and caregiver must be established

Establishing a Large-Scale Field Experiment to Assess the Effects of Artificial Light at Night on Species and Food Webs

Artificial light at night (ALAN) is one of the most obvious hallmarks of human presence in an ecosystem. The rapidly increasing use of artificial light has fundamentally transformed nightscapes throughout most of the globe, although little is known about how ALAN impacts the biodiversity and food webs of illuminated ecosystems. We developed a large-scale experimental infrastructure to study the effects of ALAN on a light-naïve, natural riparian (i.e., terrestrial-aquatic) ecosystem. Twelve street lights (20 m apart) arranged in three rows parallel to an agricultural drainage ditch were installed on each of two sites located in a grassland ecosystem in northern Germany. A range of biotic, abiotic, and photometric data are collected regularly to study the short- and long-term effects of ALAN on behavior, species interactions, physiology, and species composition of communities. Here we describe the infrastructure setup and data collection methods, and characterize the study area including photometric measurements. None of the measured parameters differed significantly between sites in the period before illumination. Results of one short-term experiment, carried out with one site illuminated and the other acting as a control, demonstrate the attraction of ALAN by the immense and immediate increase of insect catches at the lit street lights. The experimental setup provides a unique platform for carrying out interdisciplinary research on sustainable lighting

CTLA-4 Activation of Phosphatidylinositol 3-Kinase (PI 3-K) and Protein Kinase B (PKB/AKT) Sustains T-Cell Anergy without Cell Death

The balance of T-cell proliferation, anergy and apoptosis is central to immune function. In this regard, co-receptor CTLA-4 is needed for the induction of anergy and tolerance. One central question concerns the mechanism by which CTLA-4 can induce T-cell non-responsiveness without a concurrent induction of antigen induced cell death (AICD). In this study, we show that CTLA-4 activation of the phosphatidylinositol 3-kinase (PI 3-K) and protein kinase B (PKB/AKT) sustains T-cell anergy without cell death. CTLA-4 ligation induced PI 3K activation as evidenced by the phosphorylation of PKB/AKT that in turn inactivated GSK-3. The level of activation was similar to that observed with CD28. CTLA-4 induced PI 3K and AKT activation also led to phosphorylation of the pro-apoptotic factor BAD as well as the up-regulation of BcL-XL. In keeping with this, CD3/CTLA-4 co-ligation prevented apoptosis under the same conditions where T-cell non-responsiveness was induced. This effect was PI 3K and PKB/AKT dependent since inhibition of these enzymes under conditions of anti-CD3/CTLA-4 co-ligation resulted in cell death. Our findings therefore define a mechanism by which CTLA-4 can induce anergy (and possibly peripheral tolerance) by preventing the induction of cell death

“A very orderly retreat”: Democratic transition in East Germany, 1989-90

East Germany's 1989-90 democratisation is among the best known of East European transitions, but does not lend itself to comparative analysis, due to the singular way in which political reform and democratic consolidation were subsumed by Germany's unification process. Yet aspects of East Germany's democratisation have proved amenable to comparative approaches. This article reviews the comparative literature that refers to East Germany, and finds a schism between those who designate East Germany's transition “regime collapse” and others who contend that it exemplifies “transition through extrication”. It inquires into the merits of each position and finds in favour of the latter. Drawing on primary and secondary literature, as well as archival and interview sources, it portrays a communist elite that was, to a large extent, prepared to adapt to changing circumstances and capable of learning from “reference states” such as Poland. Although East Germany was the Soviet state in which the positions of existing elites were most threatened by democratic transition, here too a surprising number succeeded in maintaining their position while filing across the bridge to market society. A concluding section outlines the alchemy through which their bureaucratic power was transmuted into property and influence in the “new Germany”