Molecular spherical nucleic acids Li, Hui; Zhang, Bohan; Lu, Xueguang ...
Proceedings of the National Academy of Sciences - PNAS,
04/2018, Letnik:
115, Številka:
17
Journal Article
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Herein, we report a class of molecular spherical nucleic acid (SNA) nanostructures. These nano-sized single molecules are synthesized from T₈ polyoctahedral silsesquioxane and buckminsterfullerene ...C60 scaffolds, modified with 8 and 12 pendant DNA strands, respectively. These conjugates have different DNA surface densities and thus exhibit different levels of nuclease resistance, cellular uptake, and gene regulation capabilities; the properties displayed by the C60 SNA conjugate are closer to those of conventional and prototypical gold nanoparticle SNAs. Importantly, the C60 SNA can serve as a single entity (no transfection agent required) antisense agent to efficiently regulate gene expression. The realization of molecularly pure forms of SNAs will open the door for studying the interactions of such structures with ligands and living cells with a much greater degree of control than the conventional polydisperse forms of SNAs.
The human HDAC (histone deacetylase) family, a well-validated anticancer target, plays a key role in the control of gene expression through regulation of transcription. While HDACs can be subdivided ...into three main classes, the class I, class II and class III HDACs (sirtuins), it is presently unclear whether inhibiting multiple HDACs using pan-HDAC inhibitors, or targeting specific isoforms that show aberrant levels in tumours, will prove more effective as an anticancer strategy in the clinic. To address the above issues, we have tested a number of clinically relevant HDACis (HDAC inhibitors) against a panel of rhHDAC (recombinant human HDAC) isoforms. Eight rhHDACs were expressed using a baculoviral system, and a Fluor de Lystrade mark (Biomol International) HDAC assay was optimized for each purified isoform. The potency and selectivity of ten HDACs on class I isoforms (rhHDAC1, rhHDAC2, rhHDAC3 and rhHDAC8) and class II HDAC isoforms (rhHDAC4, rhHDAC6, rhHDAC7 and rhHDAC9) was determined. MS-275 was HDAC1-selective, MGCD0103 was HDAC1- and HDAC2-selective, apicidin was HDAC2- and HDAC3-selective and valproic acid was a specific inhibitor of class I HDACs. The hydroxamic acid-derived compounds (trichostatin A, NVP-LAQ824, panobinostat, ITF2357, vorinostat and belinostat) were potent pan-HDAC inhibitors. The growth-inhibitory effect of the HDACis on HeLa cells showed that both pan-HDAC and class-I-specific inhibitors inhibited cell growth. The results also showed that both pan-HDAC and class-I-specific inhibitor treatment resulted in increased acetylation of histones, but only pan-HDAC inhibitor treatment resulted in increased tubulin acetylation, which is in agreement with their activity towards the HDAC6 isoform.
Astrocytes establish extensive networks via gap junctions that allow each astrocyte to connect indirectly to the vasculature. However, the proportion of astrocytes directly associated with blood ...vessels is unknown. Here, we quantify structural contacts of cortical astrocytes with the vasculature in vivo. We show that all cortical astrocytes are connected to at least one blood vessel. Moreover, astrocytes contact more vessels in deeper cortical layers where vessel density is known to be higher. Further examination of different brain regions reveals that only the hippocampus, which has the lowest vessel density of all investigated brain regions, harbors single astrocytes with no apparent vascular connection. In summary, we show that almost all gray matter astrocytes have direct contact to the vasculature. In addition to the glial network, a direct vascular access may represent a complementary pathway for metabolite uptake and distribution.
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•Of all gray matter astrocytes, 99.8% are connected to at least one blood vessel•Most protoplasmic astrocytes maintain direct contact to three blood vessels•Not astrocyte size, but vessel density, defines the number of contacted vessels•Astrocytes without a direct vascular contact were found only in the hippocampus
Using in vivo and ex vivo imaging, Hösli et al. find that all gray matter astrocytes in the investigated brain regions are connected to at least one vessel. Only in the hippocampus, which showed the lowest vessel density, did they discover single astrocytes without a direct vascular contact.
The mechanisms by which astrocytes modulate neural homeostasis, synaptic plasticity, and memory are still poorly explored. Astrocytes form large intercellular networks by gap junction coupling, ...mainly composed of two gap junction channel proteins, connexin 30 (Cx30) and connexin 43 (Cx43). To circumvent developmental perturbations and to test whether astrocytic gap junction coupling is required for hippocampal neural circuit function and behavior, we generate and study inducible, astrocyte-specific Cx30 and Cx43 double knockouts. Surprisingly, disrupting astrocytic coupling in adult mice results in broad activation of astrocytes and microglia, without obvious signs of pathology. We show that hippocampal CA1 neuron excitability, excitatory synaptic transmission, and long-term potentiation are significantly affected. Moreover, behavioral inspection reveals deficits in sensorimotor performance and a complete lack of spatial learning and memory. Together, our findings establish that astrocytic connexins and an intact astroglial network in the adult brain are vital for neural homeostasis, plasticity, and spatial cognition.
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•Inducible deletion of Cx30 and Cx43 disrupts astrocytic coupling in adult mice•Loss of astrocytic connexins and coupling activate astrocytes and microglia•Astroglial networks control hippocampal synaptic transmission and plasticity•Disrupting astroglial coupling impairs spatial learning and memory
Astrocytes form large intercellular networks by gap junction coupling, but the functional importance of astrocytic coupling in adult mice remains poorly explored. Hösli et al. report that astroglial networks in the adult brain are vital for neural homeostasis, hippocampal plasticity, and spatial cognition.
Scope
We examined whether a Brassica‐rich diet was associated with an increase in the relative abundance of intestinal lactobacilli and sulphate‐reducing bacteria (SRB), or alteration to the ...composition of the gut microbiota, in healthy adults.
Methods and results
A randomised crossover study was performed with ten healthy adults who were fed a high‐ and a low‐Brassica diet for 2‐wk periods, with a 2‐wk washout phase separating the diets. The high‐Brassica diet consisted of six 84 g portions of broccoli, six 84 g portions of cauliflower and six 300 g portions of a broccoli and sweet potato soup. The low‐Brassica diet consisted of one 84 g portion of broccoli and one 84 g portion of cauliflower. Faecal microbiota composition was measured in samples collected following 2‐wk Brassica‐free periods (consumption of all Brassica prohibited), and after each diet, whereby the only Brassica consumed was that supplied by the study team. No significant changes to the relative abundance of lactobacilli were observed (p = 0.8019). The increased consumption of Brassica was associated with a reduction in the relative abundance of SRB (p = 0.0215), and members of the Rikenellaceae, Ruminococcaceae, Mogibacteriaceae, Clostridium and unclassified Clostridiales (p < 0.01).
Conclusion
The increased consumption of Brassica vegetables was linked to a reduced relative abundance of SRB, and therefore may be potentially beneficial to gastrointestinal health.
A randomised crossover study was performed with ten healthy adults to examine the effects of a low‐ and high‐Brassica diet on members of the human gut microbiota. Participants were randomised to the low–high or high–low diets, with a 2‐wk washout period separating the diets. The low‐Brassica diet consisted of two portions of Brassica foods across 2 wk, and the high‐Brassica diet contained 18 portions over 2 wk. The Brassica‐rich diet was associated with a reduction in the relative abundance of sulphate‐reducing bacteria, which have been linked to gastrointestinal disorders.
CD103
CD11b
dendritic cells (DCs) are unique to the intestine, but the factors governing their differentiation are unclear. Here we show that transforming growth factor receptor 1 (TGFβR1) has an ...indispensable, cell intrinsic role in the development of these cells. Deletion of Tgfbr1 results in markedly fewer intestinal CD103
CD11b
DCs and a reciprocal increase in the CD103
CD11b
dendritic cell subset. Transcriptional profiling identifies markers that define the CD103
CD11b
DC lineage, including CD101, TREM1 and Siglec-F, and shows that the absence of CD103
CD11b
DCs in CD11c-Cre.Tgfbr1
mice reflects defective differentiation from CD103
CD11b
intermediaries, rather than an isolated loss of CD103 expression. The defect in CD103
CD11b
DCs is accompanied by reduced generation of antigen-specific, inducible FoxP3
regulatory T cells in vitro and in vivo, and by reduced numbers of endogenous Th17 cells in the intestinal mucosa. Thus, TGFβR1-mediated signalling may explain the tissue-specific development of these unique DCs.Developmental cues for the different dendritic cell (DC) subsets in the intestine are yet to be defined. Here the authors show that TGFβR1 signalling is needed for development of CD103
CD11b
intestinal DCs from CD103
CD11b
cells and that they contribute to the generation of Th17 and regulatory T cells.
The emergence and spread of carbapenem resistance in Gram-negative bacilli such as Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii, and Pseudomonas aeruginosa through the production ...of carbapenemases is a global phenomenon. It threatens patient care and leads to therapeutic impasses. This study aims to genotypically determine the prevalence of the most frequent carbapenemase genes among multidrug-resistant E. coli strains isolated from patients at a biomedical analysis laboratory. A total of fifty-three unduplicated E. coli strains isolated from patient samples with a multidrug-resistant (MDR) profile were subjected to polymerase chain reaction (PCR) testing for carbapenem resistance genes. This study allowed us to identify fifteen strains carrying resistance genes among the fifty-three E. coli strains. All fifteen strains produced the metallo-β-lactamase enzymes; this represents a rate of 28.30% of study strains. Among these strains, ten carried the NDM resistance gene, NDM and VIM genes were detected in three strains and VIM was identified in two strains of E. coli. However, carbapenemases A (KPC and IMI), D (OXA-48), and IMP were not detected in the strains studied. Thus, NDM and VIM are the main carbapenemases detected in the strains in our study.
Biofilm formation is one of the main obstacles that occur during in vivo implantation, which compromises the implant functionality and patients’ health. This is the inspiration for the development of ...novel implant materials that contain broad-spectrum antimicrobial activity, including antibacterial and antifungal, and enable the local release of antimicrobial agents. Here, multifunctional calcium phosphate-ionic liquid (IL) materials, possessing antimicrobial and repair/regeneration features plus injectability, are proposed as implants in minimally invasive surgery. This approach was based on the loading of 1-alkyl-3-alkylimidazolium chloride ionic liquids (ILs) (C n MImCl (n = 4, 10, 16) and (C 10 ) 2 MImCl) during the in situ sol–gel synthesis of calcium phosphates (CaP) and study of their effects on CaP crystallization and biological properties. Physical, morphological, and biological investigations were performed to evaluate the bionanocomposites’ properties. The IL N-alkyl chain length influenced the crystallization of CaP and, consequently, the biological properties, which afforded bionanocomposites (when loaded with C 16 MImCl or (C 10 ) 2 MImCl) that, (i) inhibit both in vitro bacterial and fungal growth; (ii) reduce the in vitro inflammatory response; (iii) induce osteogenic differentiation in the basal medium of human mesenchymal stem cells; and (iv) are injectable. This will enable the design of multifunctional injectable implants with antimicrobial, anti-inflammatory, and regenerative properties to be used in minimally invasive surgery of bone and maxillofacial defects.
This study characterizes the future changes in extreme rainfall and air temperature in the Mono river basin where the main economic activity is weather dependent and local populations are highly ...vulnerable to natural hazards, including flood inundations. Daily precipitation and temperature from observational datasets and Regional Climate Models (RCMs) output from REMO, RegCM, HadRM3, and RCA were used to analyze climatic variations in space and time, and fit a GEV model to investigate the extreme rainfalls and their return periods. The results indicate that the realism of the simulated climate in this domain is mainly controlled by the choice of the RCMs. These RCMs projected a 1 to 1.5 °C temperature increase by 2050 while the projected trends for cumulated precipitation are null or very moderate and diverge among models. Contrasting results were obtained for the intense rainfall events, with RegCM and HadRM3 pointing to a significant increase in the intensity of extreme rainfall events. The GEV model is well suited for the prediction of heavy rainfall events although there are uncertainties beyond the 90th percentile. The annual maxima of daily precipitation will also increase by 2050 and could be of benefit to the ecosystem services and socioeconomic activities in the Mono river basin but could also be a threat.
•Sulphur intake estimation based upon methionine and cysteine overlooks contributions from other sources.•Intake estimations for sulphur from diet diary and duplicate diet agree well.•There is no ...requirement for mass re-analysis of the sulphur content of foods.•Caution is advised for diet diary analysis estimations of zinc and sodium.
Despite its importance in many areas of human metabolism, there are no recommended daily intake guide lines for sulphur. It is generally assumed that most dietary sulphur originates from intake of methionine and cysteine. We estimated sulphur intake from food diaries, and validated the results with the use of a duplicate diet analyses. Sulphur intake estimations were highly correlated with that obtain through an elemental analysis of duplicate diets, with a mean±sd daily intakes of 956±327.9mg estimated from diet diary analyses and 935±329.9mg estimated by a duplicate diet analyses. Sulphur intake from alliaceous and cruciferous vegetables contributed up to 42% of total sulphur intake. Daily intake estimation comparisons through diet diary analyses and duplicate diet for other elements showed good agreement, except for sodium and zinc, in which analyses of 24h diet dairies overestimated intake by 35% and 52%, respectively.
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