144 research outputs found

    Homeland Security als ein mögliches Konzept der umfassenden Sicherheitsvorsorge in Österreich

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    Das Ende des Ost-West-Konfliktes und die Auflösung des Warschauer Paktes haben zur Erosion der alleinigen Dominanz staatlicher Akteure im internationalen System gefĂŒhrt. Die Auseinandersetzung der SupermĂ€chte USA und UDSSR wurde durch eine FĂŒlle komplexer Bedrohungen, Gefahren und Risiken, die Großteils von substaatlichen Akteuren ausgehen, abgelöst. Nichtstaatliche Akteure, wie z.B. der Internationale Terrorismus, haben mit verdeckten Strategien traditionelle staatliche Sicherheitsmechanismen umgangen und zeigten dadurch die leichte Verwundbarkeit moderner, offener Gesellschaften auf. 9/11 und die massiven Anstrengungen der USA im Bereich Homeland Security waren fĂŒr viele europĂ€ische Staaten der Anstoß, ihre nationalen Sicherheitssysteme zu ĂŒberdenken und zumindest auf konzeptioneller Ebene, HLS-AnsĂ€tze zu berĂŒcksichtigen. Generell hat sich der Sicherheitsbegriff seit Ende des Ost-West-Konfliktes gewandelt und ist mehrdimensional und umfassend geworden. Das Prinzip der „umfassenden Sicherheit“ bildete die Grundlage fĂŒr die Überarbeitung nationaler Sicherheitskonzepte und fĂŒhrte dazu, dass Sicherheit nun mehr ĂŒber die militĂ€rische und staatliche Ebene hinaus gedacht wird und Aktionsmöglichkeiten auf mehreren Handlungsfeldern, -ebenen und -optionen zulĂ€sst. Der Mehrwert dieses Ansatzes lĂ€sst sich auf nationaler und europĂ€ischer Ebene nur schwer generieren, da national, nach wie vor das Ressortdenken im Vordergrund steht und dadurch ĂŒbergreifende AnsĂ€tze zum Teil verhindert werden. Auf der europĂ€ischen Ebene ist zu beobachten, dass viele europĂ€ische Staaten EU-Initiativen zur BewĂ€ltigung der sogenannten neuen Bedrohungen, in deren Zentrum der internationale Terrorismus steht, zwar fĂŒr gut halten, aber sich selbst betont zurĂŒckhaltend engagieren. Auf nationaler Ebene soll das Zusammenwirken der verschiedenen Politikfelder ĂŒber einen gesamtstaatlichen, ressortĂŒbergreifenden Ansatz erreicht werden, der nur durch einen Wandel der bestehenden Institutionen und Strukturen realisiert werden kann. Das in der vorliegenden Dissertation vorgestellte HLS-Prozessmodell soll ein Impuls sein, die Schwachstellen im österreichischen Sicherheitssystem zu ĂŒberwinden, sodass dieses fĂŒr die Wahrnehmung von Heimatschutzaufgaben adaptiert werden kann. Die Implementierung und Verwirklichung des HLS-Ansatzes im Rahmen der USV hĂ€ngt von politischen Entscheidungen ab, die es bis dato nicht gibt. Mit ausgewĂ€hlten AnsĂ€tzen aus den Theorien der Internationalen Beziehungen und den Organisationstheorien werden die horizontale, institutionelle und vertikale Dimension des HLS-Ansatzes sowie die Notwendigkeit einer vernetzten Sicherheitsarchitektur erklĂ€rt

    Neuronal caspase 2 activity and function requires RAIDD, but not PIDD

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    Caspase 2 was initially identified as a neuronally expressed developmentally down-regulated gene (HUGO gene nomenclature CASP2) and has been shown to be required for neuronal death induced by several stimuli, including NGF (nerve growth factor) deprivation and AÎČ (ÎČ-amyloid). In non-neuronal cells the PIDDosome, composed of caspase 2 and two death adaptor proteins, PIDD (p53-inducible protein with a death domain) and RAIDD {RIP (receptor-interacting protein)-associated ICH-1 [ICE (interleukin-1ÎČ-converting enzyme)/CED-3 (cell-death determining 3) homologue 1] protein with a death domain}, has been proposed as the caspase 2 activation complex, although the absolute requirement for the PIDDosome is not clear. To investigate the requirement for the PIDDosome in caspase-2-dependent neuronal death, we have examined the necessity for each component in induction of active caspase 2 and in execution of caspase-2-dependent neuronal death. We find that both NGF deprivation and AÎČ treatment of neurons induce active caspase 2 and that induction of this activity depends on expression of RAIDD, but is independent of PIDD expression. We show that treatment of wild-type or PIDD-null neurons with AÎČ or NGF deprivation induces formation of a complex of caspase 2 and RAIDD. We also show that caspase-2-dependent execution of neurons requires RAIDD, not PIDD. Caspase 2 activity can be induced in neurons from PIDD-null mice, and NGF deprivation or AÎČ use caspase 2 and RAIDD to execute death of these neurons

    NPM1 directs PIDDosome-dependent caspase-2 activation in the nucleolus

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    The PIDDosome (PIDD–RAIDD–caspase-2 complex) is considered to be the primary signaling platform for caspase-2 activation in response to genotoxic stress. Yet studies of PIDD-deficient mice show that caspase-2 activation can proceed in the absence of PIDD. Here we show that DNA damage induces the assembly of at least two distinct activation platforms for caspase-2: a cytoplasmic platform that is RAIDD dependent but PIDD independent, and a nucleolar platform that requires both PIDD and RAIDD. Furthermore, the nucleolar phosphoprotein nucleophosmin (NPM1) acts as a scaffold for PIDD and is essential for PIDDosome assembly in the nucleolus after DNA damage. Inhibition of NPM1 impairs caspase-2 processing, apoptosis, and caspase-2–dependent inhibition of cell growth, demonstrating that the NPM1-dependent nucleolar PIDDosome is a key initiator of the caspase-2 activation cascade. Thus we have identified the nucleolus as a novel site for caspase-2 activation and function

    RETRACTED: DNA-PKcs-PIDDosome: A Nuclear Caspase-2-Activating Complex with Role in G2/M Checkpoint Maintenance

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    This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been retracted at the request of the Authors.Our paper reported the identification of a nuclear protein complex comprising DNA-PKcs, PIDD, and caspase-2 and characterization of its role in G2/M checkpoint maintenance, thereby providing insight into the functional significance of nuclear caspase-2. We recently identified errors affecting several figure panels where original data were processed inappropriately such that the figure panels do not accurately report the original data. We believe that the most responsible course of action is to retract the paper. We sincerely apologize to the scientific community for any inconvenience this might cause

    Osteoanabolic effect of alendronate and zoledronate on bone marrow stromal cells (BMSCs) isolated from aged female osteoporotic patients and its implications for their mode of action in the treatment of age-related bone loss

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    Summary: In the present study, we evaluated the potential for aminobisphosphonates to enhance the development of bone-forming osteoblasts from progenitor cells isolated from aged female osteoporotic patients. The aminobisphosphonates tested significantly enhanced osteoblast formation and thus lend further insights into their possible mode of action in the treatment of osteoporosis. Introduction: The primary aim of this study was to evaluate the influence of aminobisphosphonates on the osteogenesis of human bone marrow stromal cells (hBMSCs) and mineralization of differentiating bone-forming cells isolated from osteoporotic patients. Methods: The influence of aminobisphosphonate treatment on hBMSC osteogenesis was assessed by the quantitative measurement of alkaline phosphatase (ALP) activity, in addition to quantitative reverse transcription polymerase chain reaction and Western blot analysis of known osteogenic markers. Mineralized matrix formation by hBMSC-derived osteoblasts was visualized and quantified using Alizarin red staining. Results: hBMSC cultures treated with osteogenic medium supplemented with zoledronate demonstrated a significant increase in Alizarin red staining after 3weeks as compared to cells cultured in osteogenic medium alone. Similarly, cultures of differentiating hBMSCs isolated from patients receiving alendronate treatment also demonstrated an increased propensity for mineralization, even in the absence of further in vitro stimulation by zoledronate. The stimulatory effects of aminobisphosphonate treatment on hBMSC-derived osteoblast-mediated mineralization were independent of any alterations in ALP activity, although significant decreases in the expression levels of osteopontin (SPP1) were evident in hBMSCs following exposure to aminobisphosphonates. Further analysis including Western blotting and loss-of-function studies revealed osteopontin as having a negative influence on the mineralization of differentiating osteoporotic bone-forming cells. Conclusions: The results presented here demonstrate for the first time that aminobisphosphonate treatment of osteoporotic hBMSCs enhances their capacity for osteoblast formation and subsequent mineral deposition, thus supporting the concept of aminobisphosphonates as having an osteoanabolic effect in osteoporosis

    Ocular neuroprotection by siRNA targeting caspase-2

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    Retinal ganglion cell (RGC) loss after optic nerve damage is a hallmark of certain human ophthalmic diseases including ischemic optic neuropathy (ION) and glaucoma. In a rat model of optic nerve transection, in which 80% of RGCs are eliminated within 14 days, caspase-2 was found to be expressed and cleaved (activated) predominantly in RGC. Inhibition of caspase-2 expression by a chemically modified synthetic short interfering ribonucleic acid (siRNA) delivered by intravitreal administration significantly enhanced RGC survival over a period of at least 30 days. This exogenously delivered siRNA could be found in RGC and other types of retinal cells, persisted inside the retina for at least 1 month and mediated sequence-specific RNA interference without inducing an interferon response. Our results indicate that RGC apoptosis induced by optic nerve injury involves activation of caspase-2, and that synthetic siRNAs designed to inhibit expression of caspase-2 represent potential neuroprotective agents for intervention in human diseases involving RGC loss

    Caspase-2-mediated cell death is required for deleting aneuploid cells

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    Caspase-2, one of the most evolutionarily conserved of the caspase family, has been implicated in maintenance of chromosomal stability and tumour suppression. Caspase-2 deficient (Casp2-/-) mice develop normally but show premature ageing-related traits and when challenged by certain stressors, succumb to enhanced tumour development and aneuploidy. To test how caspase-2 protects against chromosomal instability, we utilized an ex vivo system for aneuploidy where primary splenocytes from Casp2-/- mice were exposed to anti-mitotic drugs and followed up by live cell imaging. Our data show that caspase-2 is required for deleting mitotically aberrant cells. Acute silencing of caspase-2 in cultured human cells recapitulated these results. We further generated Casp2C320S mutant mice to demonstrate that caspase-2 catalytic activity is essential for its function in limiting aneuploidy. Our results provide direct evidence that the apoptotic activity of caspase-2 is necessary for deleting cells with mitotic aberrations to limit aneuploidy.S Dawar, Y Lim, J Puccini, M White, P Thomas, L Bouchier-Hayes, D R Green, L Dorstyn and S Kuma

    The tumor-modulatory effects of Caspase-2 and Pidd1 do not require the scaffold protein Raidd

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    The receptor-interacting protein-associated ICH-1/CED-3 homologous protein with a death domain (RAIDD/CRADD) functions as a dual adaptor and is a constituent of different multi-protein complexes implicated in the regulation of inflammation and cell death. Within the PIDDosome complex, RAIDD connects the cell death-related protease, Caspase-2, with the p53-induced protein with a death domain 1 (PIDD1). As such, RAIDD has been implicated in DNA-damage-induced apoptosis as well as in tumorigenesis. As loss of Caspase-2 leads to an acceleration of tumor onset in the EΌ-Myc mouse lymphoma model, whereas loss of Pidd1 actually delays onset of this disease, we set out to interrogate the role of Raidd in cancer in more detail. Our data obtained analyzing EΌ-Myc/Raidd(-/-) mice indicate that Raidd is unable to protect from c-Myc-driven lymphomagenesis. Similarly, we failed to observe a modulatory effect of Raidd deficiency on DNA-damage-driven cancer. The role of Caspase-2 as a tumor suppressor and that of Pidd1 as a tumor promoter can therefore be uncoupled from their ability to interact with the Raidd scaffold, pointing toward the existence of alternative signaling modules engaging these two proteins in this context.L Peintner, L Dorstyn, S Kumar, T Aneichyk, A Villunger, and C Manz

    LBH589, a deacetylase inhibitor, induces apoptosis in adult T-cell leukemia/lymphoma cells via activation of a novel RAIDD-caspase-2 pathway

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    Adult T-cell leukemia/lymphoma (ATLL), an aggressive neoplasm etiologically associated with human T-lymphotropic virus type-1 (HTLV-1), is resistant to treatment. In this study, we examined the effects of a new inhibitor of deacetylase enzymes, LBH589, on ATLL cells. LBH589 effectively induced apoptosis in ATLL-related cell lines and primary ATLL cells and reduced the size of tumors inoculated in SCID mice. Analyses, including with a DNA microarray, revealed that neither death receptors nor p53 pathways contributed to the apoptosis. Instead, LBH589 activated an intrinsic pathway through the activation of caspase-2. Furthermore, small interfering RNA experiments targeting caspase-2, caspase-9, RAIDD, p53-induced protein with a death domain (PIDD) and RIPK1 (RIP) indicated that activation of RAIDD is crucial and an event initiating this pathway. In addition, LBH589 caused a marked decrease in levels of factors involved in ATLL cell proliferation and invasion such as CCR4, IL-2R and HTLV-1 HBZ-SI, a spliced form of the HTLV-1 basic zipper factor HBZ. In conclusion, we showed that LBH589 is a strong inducer of apoptosis in ATLL cells and uncovered a novel apoptotic pathway initiated by activation of RAIDD
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