873 research outputs found
Inhibitor of Apoptosis Proteins as Novel Targets in Inflammatory Processes
Objective: Inhibitor of apoptosis proteins (IAPs), such as X-linked or cellular IAP 1/2 (XIAP, cIAP1/2), are important regulators of apoptosis. IAP antagonists are currently under clinical investigation as anticancer agents. Interestingly, IAPs participate in the inflammation-associated TNF receptor signaling complex and regulate NFκB signaling. This raises the question about the role of IAPs in inflammation. Here, we investigated the anti-inflammatory potential of IAP inhibitors and the role of IAPs in inflammatory processes of endothelial cells.
Methods and Results: In mice, the small molecule IAP antagonist A-4.10099.1 (ABT) suppressed antigen-induced arthritis, leukocyte infiltration in concanavalin A-evoked liver injury, and leukocyte transmigration in the TNFα-activated cremaster muscle. In vitro, we observed an attenuation of leukocyte– endothelial cell interaction by downregulation of the intercellular adhesion molecule-1. ABT did not impair NFκB signaling but decreased the TNFα-induced activation of the TGF-β–activated kinase 1, p38, and c-Jun N-terminal kinase. These effects are based on the proteasomal degradation of cIAP1/2 accompanied by an altered ratio of the levels of membrane-localized TNF receptor-associated factors 2 and 5.
Conclusion: Our results reveal IAP antagonism as a profound anti-inflammatory principle in vivo and highlight IAPs as important regulators of inflammatory processes in endothelial cells
Special geometry of Euclidean supersymmetry II: hypermultiplets and the c-map
We construct two new versions of the c-map which allow us to obtain the
target manifolds of hypermultiplets in Euclidean theories with rigid N =2
supersymmetry. While the Minkowskian para-c-map is obtained by dimensional
reduction of the Minkowskian vector multiplet lagrangian over time, the
Euclidean para-c-map corresponds to the dimensional reduction of the Euclidean
vector multiplet lagrangian. In both cases the resulting hypermultiplet target
spaces are para-hyper-Kahler manifolds. We review and prove the relevant
results of para-complex and para-hypercomplex geometry. In particular, we give
a second, purely geometrical construction of both c-maps, by proving that the
cotangent bundle N=T^*M of any affine special (para-)Kahler manifold M is
para-hyper-Kahler.Comment: 36 pages, 1 figur
The absence of a mature cell wall sacculus in stable Listeria monocytogenes L-form cells is independent of peptidoglycan synthesis
L-forms are cell wall-deficient variants of otherwise walled bacteria that maintain the ability to survive and proliferate in absence of the surrounding peptidoglycan sacculus. While transient or unstable L-forms can revert to the walled state and may still rely on residual peptidoglycan synthesis for multiplication, stable L-forms cannot revert to the walled form and are believed to propagate in the complete absence of peptidoglycan. L-forms are increasingly studied as a fundamental biological model system for cell wall synthesis. Here, we show that a stable L-form of the intracellular pathogen Listeria monocytogenes features a surprisingly intact peptidoglycan synthesis pathway including glycosyl transfer, in spite of the accumulation of multiple mutations during prolonged passage in the cell wall-deficient state. Microscopic and biochemical analysis revealed the presence of peptidoglycan precursors and functional glycosyl transferases, resulting in the formation of peptidoglycan polymers but without the synthesis of a mature cell wall sacculus. In conclusion, we found that stable, non-reverting L-forms, which do not require active PG synthesis for proliferation, may still continue to produce aberrant peptidoglycan
Quantifying the effect of ocean bed properties on ice sheet geometry over 40 000 years with a full-Stokes model
Simulations of ice sheet evolution over glacial cycles require integration of observational constraints using ensemble studies with fast ice sheet models. These include physical parameterisations with uncertainties, for example, relating to grounding-line migration. More complete ice dynamic models are slow and have thus far only be applied for 50 % under almost equal forcing. Grounding-line positions differ by up to 49 km, show significant hysteresis, and migrate non-steadily in both scenarios with long quiescent phases disrupted by leaps of rapid migration. The simulations quantify the evolution of two different ice sheet geometries (namely thick and slow vs. thin and fast), triggered by the variable grounding-line migration over the differing ocean beds. Our study extends the timescales of 3D full-Stokes by an order of magnitude compared to previous studies with the help of parallelisation. The extended time frame for full-Stokes models is a first step towards better understanding other processes such as erosion and sediment redistribution in the ice shelf cavity impacting the entire catchment geometry
Excess resource use and costs of physical comorbidities in individuals with mental health disorders: A systematic literature review and meta-analysis
Individuals with mental health disorders (MHDs) have worse physical health than the general population, utilise healthcare resources more frequently and intensively, incurring higher costs. We provide a first comprehensive overview and quantitative synthesis of literature on the mag- nitude of excess resource use and costs for those with MHDs and comorbid physical health condi- tions (PHCs). This systematic review (PROSPERO CRD42017075319) searched studies comparing resource use or costs of individuals with MHDs and comorbid PHCs versus individuals without co- morbid conditions published between 2007 and 2021. We conducted narrative and quantitative syntheses, using random-effects meta-analyses to explore ranges of excess resource use and costs across care segments, comparing to MHD only, PHC only, or general population controls (GPC). Of 20,075 records, 228 and 100 were eligible for narrative and quantitative syntheses, respectively. Most studies were from the US, covered depression or schizophrenia, reporting endocrine/metabolic or circulatory comorbidities. Frequently investigated healthcare segments were inpatient, outpatient, emergency care and medications. Evidence on lost productivity, long-term and informal care was rare. Substantial differences exist between MHDs, with depressive disorder tending towards lower average excess resource use and cost estimates, while excess resource use ranges between +6% to +320% and excess costs between +14% to +614%. PHCs are major drivers of resource use and costs for individuals with MHDs, affecting care segments differently. Significant physical health gains and cost savings are potentially achievable through prevention, earlier identification, management and treatment, using more integrated care approaches. Current international evidence, however, is heterogeneous with limited geographical representativeness and comparability
The exo-β-N-acetylmuramidase NamZ from Bacillus subtilis is the founding member of a family of exo-lytic peptidoglycan hexosaminidases
Endo-β-N-acetylmuramidases, commonly known as lysozymes, are well-characterized antimicrobial enzymes that catalyze an endo-lytic cleavage of peptidoglycan; i.e., they hydrolyze
the β-1,4-glycosidic bonds connecting N-acetylmuramic acid
(MurNAc) and N-acetylglucosamine (GlcNAc). In contrast, little
is known about exo-β-N-acetylmuramidases, which catalyze
an exo-lytic cleavage of β-1,4-MurNAc entities from the
non-reducing ends of peptidoglycan chains. Such an enzyme
was identified earlier in the bacterium Bacillus subtilis, but the
corresponding gene has remained unknown so far. We now
report that ybbC of B. subtilis, renamed namZ, encodes the
reported exo-β-N-acetylmuramidase. A ΔnamZ mutant accumulated specific cell wall fragments and showed growth defects
under starvation conditions, indicating a role of NamZ in cell
wall turnover and recycling. Recombinant NamZ protein
specifically hydrolyzed the artificial substrate para-nitrophenyl
β-MurNAc and the peptidoglycan-derived disaccharide MurNAc-β-1,4-GlcNAc. Together with the exo-β-N-acetylglucosaminidase NagZ and the exo-muramoyl-L-alanine amidase AmiE,
NamZ degraded intact peptidoglycan by sequential hydrolysis
from the non-reducing ends. A structure model of NamZ, built
on the basis of two crystal structures of putative orthologs from
Bacteroides fragilis, revealed a two-domain structure including a
Rossmann-fold-like domain that constitutes a unique glycosidase fold. Thus, NamZ, a member of the DUF1343 protein
family of unknown function, is now classified as the founding
member of a new family of glycosidases (CAZy GH171; www.
cazy.org/GH171.html). NamZ-like peptidoglycan hexosaminidases are mainly present in the phylum Bacteroidetes and less
frequently found in individual genomes within Firmicutes
(Bacilli, Clostridia), Actinobacteria, and γ-proteobacteria
The Kahler Cone as Cosmic Censor
M-theory effects prevent five-dimensional domain-wall and black-hole
solutions from developing curvature singularities. While so far this analysis
was performed for particular models, we now present a model-independent proof
that these solutions do not have naked singularities as long as the Kahler
moduli take values inside the extended Kahler cone. As a by-product we obtain
information on the regularity of the Kahler-cone metric at boundaries of the
Kahler cone and derive relations between the geometry of moduli space and
space-time.Comment: 21 pages, 1 figure. Improved discussion of the relation between
Kahler moduli and five-dimensional scalars. No changes in the conclusion
Antiphase Boundaries Constitute Fast Cation Diffusion Paths in SrTiO3 Memristive Devices
AbstractResistive switching in transition metal oxide‐based metal‐insulator‐metal structures relies on the reversible drift of ions under an applied electric field on the nanoscale. In such structures, the formation of conductive filaments is believed to be induced by the electric‐field driven migration of oxygen anions, while the cation sublattice is often considered to be inactive. This simple mechanistic picture of the switching process is incomplete as both oxygen anions and metal cations have been previously identified as mobile species under device operation. Here, spectromicroscopic techniques combined with atomistic simulations to elucidate the diffusion and drift processes that take place in the resistive switching model material SrTiO3 are used. It is demonstrated that the conductive filament in epitaxial SrTiO3 devices is not homogenous but exhibits a complex microstructure. Specifically, the filament consists of a conductive Ti3+‐rich region and insulating Sr‐rich islands. Transmission electron microscopy shows that the Sr‐rich islands emerge above Ruddlesden–Popper type antiphase boundaries. The role of these extended defects is clarified by molecular static and molecular dynamic simulations, which reveal that the Ruddlesden–Popper antiphase boundaries constitute diffusion fast‐paths for Sr cations in the perovskites structure
An Antibody-Aptamer-Hybrid Lateral Flow Assay for Detection of CXCL9 in Antibody-Mediated Rejection after Kidney Transplantation
Chronic antibody-mediated rejection (AMR) is a key limiting factor for the clinical outcome of a kidney transplantation (Ktx), where early diagnosis and therapeutic intervention is needed. This study describes the identification of the biomarker CXC-motif chemokine ligand (CXCL) 9 as an indicator for AMR and presents a new aptamer-antibody-hybrid lateral flow assay (hybrid-LFA) for detection in urine. Biomarker evaluation included two independent cohorts of kidney transplant recipients (KTRs) from a protocol biopsy program and used subgroup comparisons according to BANFF-classifications. Plasma, urine and biopsy lysate samples were analyzed with a Luminex-based multiplex assay. The CXCL9-specific hybrid-LFA was developed based upon a specific rat antibody immobilized on a nitrocellulose-membrane and the coupling of a CXCL9-binding aptamer to gold nanoparticles. LFA performance was assessed according to receiver operating characteristic (ROC) analysis. Among 15 high-scored biomarkers according to a neural network analysis, significantly higher levels of CXCL9 were found in plasma and urine and biopsy lysates of KTRs with biopsy-proven AMR. The newly developed hybrid-LFA reached a sensitivity and specificity of 71% and an AUC of 0.79 for CXCL9. This point-of-care-test (POCT) improves early diagnosis-making in AMR after Ktx, especially in KTRs with undetermined status of donor-specific HLA-antibodies
Myeloproliferative Diseases as Possible Risk Factor for Development of Chronic Thromboembolic Pulmonary Hypertension—A Genetic Study
Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare disease which is often
caused by recurrent emboli. These are also frequently found in patients with myeloproliferative
diseases. While myeloproliferative diseases can be caused by gene defects, the genetic predisposition
to CTEPH is largely unexplored. Therefore, the objective of this study was to analyse these genes
and further genes involved in pulmonary hypertension in CTEPH patients. A systematic screening
was conducted for pathogenic variants using a gene panel based on next generation sequencing.
CTEPH was diagnosed according to current guidelines. In this study, out of 40 CTEPH patients
4 (10%) carried pathogenic variants. One patient had a nonsense variant (c.2071A>T p.Lys691*)
in the BMPR2 gene and three further patients carried the same pathogenic variant (missense variant,
c.1849G>T p.Val617Phe) in the Janus kinase 2 (JAK2) gene. The latter led to a myeloproliferative
disease in each patient. The prevalence of this JAK2 variant was significantly higher than expected
(p < 0.0001). CTEPH patients may have a genetic predisposition more often than previously thought.
The predisposition for myeloproliferative diseases could be an additional risk factor for CTEPH
development. Thus, clinical screening for myeloproliferative diseases and genetic testing may be
considered also for CTEPH patients
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