The influenza viruses cause annual epidemics of respiratory disease and occasional pandemics, which constitute a major public-health issue. The segmented negative-stranded RNAs are associated with ...the polymerase complex and nucleoprotein (NP), forming ribonucleoproteins (RNPs), which are responsible for virus transcription and replication. We describe the structure of native RNPs derived from virions. They show a double-helical conformation in which two NP strands of opposite polarity are associated with each other along the helix. Both strands are connected by a short loop at one end of the particle and interact with the polymerase complex at the other end. This structure will be relevant for unraveling the mechanisms of nuclear import of parental virus RNPs, their transcription and replication, and the encapsidation of progeny RNPs into virions.
T-cell exhaustion has been involved in the pathogenesis of HIV infection. We have longitudinally analyzed PD1 and Tim3 surrogate markers of T-cells exhaustion, in parallel with other markers of HIV ...progression, and its potential association with CD4 changes in treated and untreated infection.
96 HIV patients, 49 of them followed in the absence of cART (cART-naïve group) and 47 after initiation of cART (cART group) were included and followed for a median of 43 IQR: 31-60 months. PD1 and Tim3 expression, CD8 T-cells activation, recent thymic emigrants, activation/apoptosis and turnover of CD4 cells were assessed at baseline and during follow up. Univariate and multivariate associations with CD4 evolution were explored.
Parameters significantly associated with CD4 depletion in cART-naïve group were: baseline level (p = 0.02) and variation (p = 0.002) of PD1 and Tim3 co-expression on CD8, and variation of CD95 expression on CD4 (p = 0.007). Parameters significantly associated with CD4 restoration in cART group were: baseline level of CD38+HLADR- subset of CD8 (p = 0.01), variation of PD1 expression on CD8 (p = 0.036), variation of Tim3 expression on CD4 (p = 0.039) and variation of CD95 expression on CD4 (p = 0.035).
Our results suggest that PD1 and Tim3 markers of exhaustion have a pivotal role in CD4 dynamics in HIV patients and its down-regulation would be a desirable effect of immunotherapies aimed to restore CD4 T-cell pool during progression of HIV infection.
Background Although empiric exclusion from the diet of the 6 food groups most likely to trigger allergies achieves eosinophilic esophagitis (EoE) remission in children, data on its prolonged efficacy ...and effects on adults are lacking. Objective We sought to evaluate the efficacy of a 6-food elimination diet in inducing and maintaining prolonged remission in patients with adult EoE. Methods Sixty-seven consecutive patients with adult EoE were prospectively recruited and treated exclusively with a diet avoiding cereals, milk, eggs, fish/seafood, legumes/peanuts, and soy for 6 weeks. Subsequent challenge was undertaken by sequentially reintroducing all excluded single foods, followed by endoscopy and biopsies, which were developed every 6 weeks in case of response (eosinophil peak count reduction to <15/high-power field hpf). A food was considered a trigger for EoE and removed from the diet if pathologic eosinophilic infiltration (≥15 eosinophils/hpf) reappeared. Food-specific serum IgE measurements and skin prick tests were performed before initiating the diet. Results Forty-nine (73.1%) patients exhibited significantly reduced eosinophil peak counts (<15 eosinophils/hpf) before sequential single-food reintroduction. A single offending food antigen was identified in 35.71% of patients, 2 food triggers were identified in 30.95%, and 3 or more food triggers were identified in 33.3%. Cow's milk was the most common food antigen (61.9%), followed by wheat (28.6%), eggs (26.2%), and legumes (23.8%). Prior allergy tests showed no concordance with food-reintroduction challenge results. All patients who continued to avoid the offending foods maintained histopathologic and clinical EoE remission for up to 3 years. Conclusions An empiric 6-food elimination diet effectively induced remission of active adult EoE, which was maintained for up to 3 years with individually tailored, limited exclusion diets.
To propose a new objective scatter index (OSI) based in the analysis of double-pass images of a point source to rank and classify cataract patients. This classification scheme is compared with a ...current subjective system.
We selected a population including a group of normal young eyes as control and patients diagnosed with cataract (grades NO2, NO3 and NO4) according to the Lens Opacities Classification System (LOCS III). For each eye, we recorded double-pass retinal images of a point source. In each patient, we determined an objective scatter index (OSI) as the ratio of the intensity at an eccentric location in the image and the central part. This index provides information on the relevant forward scatter affecting vision. Since the double-pass retinal images are affected by both ocular aberrations and intraocular scattering, an analysis was performed to show the ranges of contributions of aberrations to the OSI.
We used the OSI values to classify each eye according to the degree of scatter. The young normal eyes of the control group had OSI values below 1, while the OSI for subjects in LOCS grade II were around 1 to 2. The use of the objective index showed some of the weakness of subjective classification schemes. In particular, several subjects initially classified independently as grade NO2 or NO3 had similar OSI values, and in some cases even higher than subjects classified as grade NO4. A new classification scheme based in OSI is proposed.
We introduced an objective index based in the analysis of double-pass retinal images to classify cataract patients. The method is robust and fully based in objective measurements; i.e., not depending on subjective decisions. This procedure could be used in combination with standard current methods to improve cataract patient surgery scheduling.
The influenza viruses contain a segmented, single-stranded RNA genome of negative polarity. Each RNA segment is encapsidated by the nucleoprotein and the polymerase complex into ribonucleoprotein ...particles (RNPs), which are responsible for virus transcription and replication. Despite their importance, information about the structure of these RNPs is scarce. We have determined the three-dimensional structure of a biologically active recombinant RNP by cryo-electron microscopy. The structure shows a nonameric nucleoprotein ring (at 12 Angstrom resolution) with two monomers connected to the polymerase complex (at 18 Angstrom resolution). Docking the atomic structures of the nucleoprotein and polymerase domains, as well as mutational analyses, has allowed us to define the interactions between the functional elements of the RNP and to propose the location of the viral RNA. Our results provide the first model for a functional negative-stranded RNA virus ribonucleoprotein complex. The structure reported here will serve as a framework to generate a quasi-atomic model of the molecular machine responsible for viral RNA synthesis and to test new models for virus RNA replication and transcription.
Intracellular pathogens alter their host cells' mechanics to promote dissemination through tissues. Conversely, host cells may respond to the presence of pathogens by altering their mechanics to ...limit infection. Here, we monitored epithelial cell monolayers infected with intracellular bacterial pathogens, Listeria monocytogenes or Rickettsia parkeri, over days. Under conditions in which these pathogens trigger innate immune signaling through NF-κB and use actin-based motility to spread non-lytically intercellularly, we found that infected cell domains formed three-dimensional mounds. These mounds resulted from uninfected cells moving toward the infection site, collectively squeezing the softer and less contractile infected cells upward and ejecting them from the monolayer. Bacteria in mounds were less able to spread laterally in the monolayer, limiting the growth of the infection focus, while extruded infected cells underwent cell death. Thus, the coordinated forceful action of uninfected cells actively eliminates large domains of infected cells, consistent with this collective cell response representing an innate immunity-driven process.
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•Epithelial host cells form extruded mounds after infection with L. monocytogenes•3D mounds result from mechanical competition between infected and uninfected cells•Inhibition of cell-matrix and/or cell-cell forces inhibits infection mound formation•Innate immune signals control this mechanical competition that limits pathogen spread
Bastounis et al. show that, during infection with the intracellular bacterial pathogen L. monocytogenes, large infected domains in epithelial cell monolayers extrude to form three-dimensional mounds due to the collective onslaught by their uninfected neighbors. This mechanical competition between uninfected and bacterially infected cells limits pathogen dissemination through the epithelium.
Neurons are usually regarded as postmitotic cells that undergo apoptosis in response to cell cycle reactivation. Nevertheless, recent evidence indicates the existence of a defined developmental ...program that induces DNA replication in specific populations of neurons, which remain in a tetraploid state for the rest of their adult life. Similarly, de novo neuronal tetraploidization has also been described in the adult brain as an early hallmark of neurodegeneration. The aim of this review is to integrate these recent developments in the context of cell cycle regulation and apoptotic cell death in neurons. We conclude that a variety of mechanisms exists in neuronal cells for G1/S and G2/M checkpoint regulation. These mechanisms, which are connected with the apoptotic machinery, can be modulated by environmental signals and the neuronal phenotype itself, thus resulting in a variety of outcomes ranging from cell death at the G1/S checkpoint to full proliferation of differentiated neurons.
Cyclodextrin-based gene delivery systems Ortiz Mellet, Carmen; García Fernández, José M; Benito, Juan M
Chemical Society reviews
40, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Cyclodextrin (CD) history has been largely dominated by their unique ability to form inclusion complexes with guests fitting in their hydrophobic cavity. Chemical funcionalization was soon recognized ...as a powerful mean for improving CD applications in a wide range of fields, including drug delivery, sensing or enzyme mimicking. However, 100 years after their discovery, CDs are still perceived as novel nanoobjects of undeveloped potential. This critical review provides an overview of different strategies to promote interactions between CD conjugates and genetic material by fully exploiting the inside-outside/upper-lower face anisotropy of the CD nanometric platform. Covalent modification, self-assembling and supramolecular ligation can be put forward with the ultimate goal to build artificial viruses for programmed and efficient gene therapy (222 references).
Nanomaterials offer exciting properties and functionalities. However, their production and processing frequently involve complex methods, cumbersome equipment, harsh conditions, and hazardous media. ...The capability of organisms to accomplish this using mild conditions offers a sustainable, biocompatible, and environmentally friendly alternative. Different nanomaterials such as metal nanoparticles, quantum dots, silica nanostructures, and nanocellulose are being synthesized increasingly through living entities. In addition, the bionanofabrication potential enables also the in situ processing of nanomaterials inside biomatrices with unprecedented outcomes. In this Minireview we present a critical state‐of‐the‐art vision of current nanofabrication approaches mediated by living entities (ranging from unicellular to higher organisms), in order to expand this knowledge and scrutinize future prospects. An efficient interfacial interaction at the nanoscale by green means is within reach through this approach.
Green living nanofactories: Nanomaterials (NMs) and nanocomposites are typically prepared by procedures that are incompatible with green chemistry and sustainability principles. But some living entities, from single cells to higher organisms, are able to synthesize and process NMs very efficiently under milder conditions. In this Minireview, the advances and prospects of this growing trend are discussed and summarized.
The ability of cyclodextrin‐based polycationic cluster to undergo reversible DNA condensation and release in a physiologically useful pH window has been finely tuned by the installation of a capping ...xylylene moiety at the secondary face of the cyclooligosaccharide. This strategy can be exploited advantageously in the design of self‐assembling nonviral gene‐delivery systems from molecular entities.
Programming self‐assembly: pH‐Sensitive, hierarchical self‐assembly of cyclodextrin‐based polycationic clusters and DNA was programmed by the installation of a xylylene moiety at the secondary face of the cyclooligosaccharide. At neutral pH dimer formation facilitates DNA condensation, whereas at acidic pH electrostatic repulsions promote disassembly of the nanocomplexes and DNA release. This can be exploited advantageously in the design of nonviral gene delivery systems (see figure).
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