Nuclear retention of IL-1 alpha by necrotic cells: A mechanism to dampen sterile inflammation

Sterile inflammation is a host response to tissue injury that is mediated by damage-associated molecular patterns (DAMPs) released from dead cells. Sterile inflammation worsens damage in a number of injury paradigms. The pro-inflammatory cytokine interleukin-1α (IL-1α) is reported to be a DAMP released from dead cells, and is known to exacerbate brain injury caused by stroke. In the brain, IL-1α is produced by microglia, the resident brain macrophages. We found that IL-1α is actively trafficked to the nuclei of microglia, and hence tested the hypothesis that trafficking of IL-1α to the nucleus would inhibit its release following necrotic cell death, limiting sterile inflammation. Microglia subjected to oxygen-glucose deprivation (OGD) died via necrosis. Under these conditions, microglia expressing nuclear IL-1α released significantly less IL-1α than microglia with predominantly cytosolic IL-1α. The remaining IL-1α was immobilised in the nuclei of the dead cells. Thus, nuclear retention of IL-1α may serve to limit inflammation following cell death

Moving pathogen genomics out of the lab and into the clinic: what will it take?

Pathogen genomic analysis is a potentially transformative new approach to the clinical and public-health management of infectious diseases. Health systems investing in this technology will need to build infrastructure and develop policies that ensure genomic information can be generated, shared and acted upon in a timely manner

Direct observations of amyloid β self-assembly in live cells provide insights into differences in the kinetics of Aβ(1-40) and Aβ(1-42) aggregation.

Insight into how amyloid β (Aβ) aggregation occurs in vivo is vital for understanding the molecular pathways that underlie Alzheimer's disease and requires new techniques that provide detailed kinetic and mechanistic information. Using noninvasive fluorescence lifetime recordings, we imaged the formation of Aβ(1-40) and Aβ(1-42) aggregates in live cells. For both peptides, the cellular uptake via endocytosis is rapid and spontaneous. They are then retained in lysosomes, where their accumulation leads to aggregation. The kinetics of Aβ(1-42) aggregation are considerably faster than those of Aβ(1-40) and, unlike those of the latter peptide, show no detectable lag phase. We used superresolution fluorescence imaging to examine the resulting aggregates and could observe compact amyloid structures, likely because of spatial confinement within cellular compartments. Taken together, these findings provide clues as to how Aβ aggregation may occur within neurons

Zinc depletion regulates the processing and secretion of IL-1β.

Sterile inflammation contributes to many common and serious human diseases. The pro-inflammatory cytokine interleukin-1β (IL-1β) drives sterile inflammatory responses and is thus a very attractive therapeutic target. Activation of IL-1β in sterile diseases commonly requires an intracellular multi-protein complex called the NLRP3 (NACHT, LRR, and PYD domains-containing protein 3) inflammasome. A number of disease-associated danger molecules are known to activate the NLRP3 inflammasome. We show here that depletion of zinc from macrophages, a paradigm for zinc deficiency, also activates the NLRP3 inflammasome and induces IL-1β secretion. Our data suggest that zinc depletion damages the integrity of lysosomes and that this event is important for NLRP3 activation. These data provide new mechanistic insight to how zinc deficiency contributes to inflammation and further unravel the mechanisms of NLRP3 inflammasome activation

Intrinsic determinants of neurotoxic aggregate formation by the amyloid β peptide

The extent to which proteins aggregate into distinct structures ranging from prefibrillar oligomers to amyloid fibrils is key to the pathogenesis of many age-related degenerative diseases. We describe here for the Alzheimer's disease-related amyloid β peptide (Aβ) an investigation of the sequence-based determinants of the balance between the formation of prefibrillar aggregates and amyloid fibrils. We show that by introducing single-point mutations, it is possible to convert the normally harmless Aβ40 peptide into a pathogenic species by increasing its relative propensity to form prefibrillar but not fibrillar aggregates, and, conversely, to abolish the pathogenicity of the highly neurotoxic E22G Aβ42 peptide by reducing its relative propensity to form prefibrillar species rather than mature fibrillar ones. This observation can be rationalized by the demonstration that whereas regions of the sequence of high aggregation propensity dominate the overall tendency to aggregate, regions with low intrinsic aggregation propensities exert significant control over the balance of the prefibrillar and fibrillar species formed, and therefore play a major role in determining the neurotoxicity of the Aβ peptide. © 2010 by the Biophysical Society

Generic Mechanism of Emergence of Amyloid Protofilaments from Disordered Oligomeric aggregates

The presence of oligomeric aggregates, which is often observed during the process of amyloid formation, has recently attracted much attention since it has been associated with neurodegenerative conditions such as Alzheimer's and Parkinson's diseases. We provide a description of a sequence-indepedent mechanism by which polypeptide chains aggregate by forming metastable oligomeric intermediate states prior to converting into fibrillar structures. Our results illustrate how the formation of ordered arrays of hydrogen bonds drives the formation of beta-sheets within the disordered oligomeric aggregates that form early under the effect of hydrophobic forces. Initially individual beta-sheets form with random orientations, which subsequently tend to align into protofilaments as their lengths increases. Our results suggest that amyloid aggregation represents an example of the Ostwald step rule of first order phase transitions by showing that ordered cross-beta structures emerge preferentially from disordered compact dynamical intermediate assemblies.Comment: 14 pages, 4 figure

Clusterin protects neurons against intracellular proteotoxicity.

It is now widely accepted in the field that the normally secreted chaperone clusterin is redirected to the cytosol during endoplasmic reticulum (ER) stress, although the physiological function(s) of this physical relocation remain unknown. We have examined in this study whether or not increased expression of clusterin is able to protect neuronal cells against intracellular protein aggregation and cytotoxicity, characteristics that are strongly implicated in a range of neurodegenerative diseases. We used the amyotrophic lateral sclerosis-associated protein TDP-43 as a primary model to investigate the effects of clusterin on protein aggregation and neurotoxicity in complementary in vitro, neuronal cell and Drosophila systems. We have shown that clusterin directly interacts with TDP-43 in vitro and potently inhibits its aggregation, and observed that in ER stressed neuronal cells, clusterin co-localized with TDP-43 and specifically reduced the numbers of cytoplasmic inclusions. We further showed that the expression of TDP-43 in transgenic Drosophila neurons induced ER stress and that co-expression of clusterin resulted in a dramatic clearance of mislocalized TDP-43 from motor neuron axons, partially rescued locomotor activity and significantly extended lifespan. We also showed that in Drosophila photoreceptor cells, clusterin co-expression gave ER stress-dependent protection against proteotoxicity arising from both Huntingtin-Q128 and mutant (R406W) human tau. We therefore conclude that increased expression of clusterin can provide an important defense against intracellular proteotoxicity under conditions that mimic specific features of neurodegenerative disease

Особливості планування і реалізації проектів ресторанного бізнесу

Ресторанний бізнес є однією із найбільш значущих складових індустрії гостинності. Водночас, ресторанний бізнес, з одного боку, є одним із засобів високоліквідного використання капіталу, а з іншого − середовищем із високим ступенем конкурентності. У всьому світі він є одним із найбільш розповсюджених видів малого бізнесу, тому заклади та підприємства ведуть між собою постійну боротьбу за сегментацію ринку, за пошук нових та за утримання постійних споживачів їхньої продукції та послуг. Всі заклади та підприємства повинні мати високий рівень конкурентоспроможності та мати свою унікальність