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1.
Adv Mater ; 35(45): e2303528, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37450343

RESUMO

Addition of aqueous hydrohalic acids during the synthesis of colloidal quantum dots (QDs) is widely employed to achieve high-quality QDs. However, this reliance on the use of aqueous solutions is incompatible with oxygen- and water-sensitive precursors such as those used in the synthesis of Te-alloyed ZnSe QDs. Herein, it is shown that this incompatibility leads to phase segregation into Te-rich and Te-poor regions, causing spectral broadening and luminescence peak shifting under high laser irradiation and applied electrical bias. Here, a synthetic strategy to produce anhydrous-HF in situ by using benzenecarbonyl fluoride (BF) as a chemical additive is reported. Through in situ 19 F NMR spectroscopy, it is found that BF reacts with surfactants in tandem, ultimately producing intermediary F···H···trioctylamine adducts. These act as a pseudo-HF source that releases anhydrous HF. The controlled release of HF during nucleation and growth steps homogenizes Te distribution in ZnSeTe lattice, leading to spectrally stable blue-emitting QDs under increasing laser flux from ≈3 µW to ≈12 mW and applied bias from 2.6 to 10 V. Single-dot photoluminescence (PL) spectroscopy and analyses of the absorption, PL and transient absorption spectra together with density functional theory point to the role of anhydrous HF as a Te homogenizer.

2.
Plant Sci ; 330: 111659, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36813242

RESUMO

Complete defoliation of trees due to periodic LDD (Lymantria dispar dispar) moth outbreaks in many parts of the world is a significant stress factor for the survival of individual trees and entire forests over vast areas. This study addresses such a mid-summer defoliation event in Ontario, Canada for quaking aspen trees during 2021. It is shown that complete refoliation in the same year is possible for these trees, albeit with significantly smaller leaf size. Regrown leaves showed the well-known non-wetting behaviour typically observed for the quaking aspen tree without a defoliation event. These leaves have the same hierarchical dual-scale surface structure consisting of nanometre-size epicuticular wax (ECW) crystals superimposed on micrometre-sized papillae. This structure provides for the Cassie-Baxter non-wetting state with a very high water contact angle on the adaxial surface of the leaves. Subtle differences in the leaf surface morphology of the refoliation leaves compared with the regular growth leaves are likely due to environmental factors such as seasonal temperature during the leaf growth period after budbreak.


Assuntos
Mariposas , Populus , Roma (Grupo Étnico) , Animais , Humanos , Folhas de Planta , Árvores
3.
Gut ; 72(4): 671-685, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-35705368

RESUMO

OBJECTIVE: Conflicting microbiota data exist for primary sclerosing cholangitis (PSC) and experimental models. GOAL: define the function of complex resident microbes and their association relevant to PSC patients by studying germ-free (GF) and antibiotic-treated specific pathogen-free (SPF) multidrug-resistant 2 deficient (mdr2-/- ) mice and microbial profiles in PSC patient cohorts. DESIGN: We measured weights, liver enzymes, RNA expression, histological, immunohistochemical and fibrotic biochemical parameters, faecal 16S rRNA gene profiling and metabolomic endpoints in gnotobiotic and antibiotic-treated SPF mdr2-/- mice and targeted metagenomic analysis in PSC patients. RESULTS: GF mdr2-/- mice had 100% mortality by 8 weeks with increasing hepatic bile acid (BA) accumulation and cholestasis. Early SPF autologous stool transplantation rescued liver-related mortality. Inhibition of ileal BA transport attenuated antibiotic-accelerated liver disease and decreased total serum and hepatic BAs. Depletion of vancomycin-sensitive microbiota exaggerated hepatobiliary disease. Vancomycin selectively decreased Lachnospiraceae and short-chain fatty acids (SCFAs) but expanded Enterococcus and Enterobacteriaceae. Antibiotics increased Enterococcus faecalis and Escherichia coli liver translocation. Colonisation of GF mdr2-/- mice with translocated E. faecalis and E. coli strains accelerated hepatobiliary inflammation and mortality. Lachnospiraceae colonisation of antibiotic pretreated mdr2-/- mice reduced liver fibrosis, inflammation and translocation of pathobionts, and SCFA-producing Lachnospiraceae and purified SCFA decreased fibrosis. Faecal Lachnospiraceae negatively associated, and E. faecalis/ Enterobacteriaceae positively associated, with PSC patients' clinical severity by Mayo risk scores. CONCLUSIONS: We identified novel functionally protective and detrimental resident bacterial species in mdr2-/- mice and PSC patients with associated clinical risk score. These insights may guide personalised targeted therapeutic interventions in PSC patients.


Assuntos
Escherichia coli , Vancomicina , Animais , Camundongos , Modelos Animais de Doenças , RNA Ribossômico 16S/genética , Inflamação , Cirrose Hepática , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Clostridiales
4.
Infect Immun ; 90(4): e0007022, 2022 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-35311578

RESUMO

Persistent infections generally involve a complex balance between protective immunity and immunopathology. We used a murine model to investigate the role of inflammatory monocytes in immunity and host defense against persistent salmonellosis. Mice exhibit increased susceptibility to persistent infection when inflammatory monocytes cannot be recruited into tissues or when they are depleted at specific stages of persistent infection. Inflammatory monocytes contribute to the pathology of persistent salmonellosis and cluster with other cells in pathogen-containing granulomas. Depletion of inflammatory monocytes during the chronic phase of persistent salmonellosis causes regression of already established granulomas with resultant pathogen growth and spread in tissues. Thus, inflammatory monocytes promote granuloma-mediated control of persistent salmonellosis and may be key to uncovering new therapies for granulomatous diseases.


Assuntos
Monócitos , Infecções por Salmonella , Animais , Granuloma , Camundongos , Receptores CCR2
5.
J Cheminform ; 13(1): 63, 2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34479624

RESUMO

The prediction of metabolism and biotransformation pathways of xenobiotics is a highly desired tool in environmental sciences, drug discovery, and (eco)toxicology. Several systems predict single transformation steps or complete pathways as series of parallel and subsequent steps. Their performance is commonly evaluated on the level of a single transformation step. Such an approach cannot account for some specific challenges that are caused by specific properties of biotransformation experiments. That is, missing transformation products in the reference data that occur only in low concentrations, e.g. transient intermediates or higher-generation metabolites. Furthermore, some rule-based prediction systems evaluate the performance only based on the defined set of transformation rules. Therefore, the performance of these models cannot be directly compared. In this paper, we introduce a new evaluation framework that extends the evaluation of biotransformation prediction from single transformations to whole pathways, taking into account multiple generations of metabolites. We introduce a procedure to address transient intermediates and propose a weighted scoring system that acknowledges the uncertainty of higher-generation metabolites. We implemented this framework in enviPath and demonstrate its strict performance metrics on predictions of in vitro biotransformation and degradation of xenobiotics in soil. Our approach is model-agnostic and can be transferred to other prediction systems. It is also capable of revealing knowledge gaps in terms of incompletely defined sets of transformation rules.

6.
Nat Commun ; 12(1): 3387, 2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-34099705

RESUMO

The renewable-electricity-powered CO2 electroreduction reaction provides a promising means to store intermittent renewable energy in the form of valuable chemicals and dispatchable fuels. Renewable methane produced using CO2 electroreduction attracts interest due to the established global distribution network; however, present-day efficiencies and activities remain below those required for practical application. Here we exploit the fact that the suppression of *CO dimerization and hydrogen evolution promotes methane selectivity: we reason that the introduction of Au in Cu favors *CO protonation vs. C-C coupling under low *CO coverage and weakens the *H adsorption energy of the surface, leading to a reduction in hydrogen evolution. We construct experimentally a suite of Au-Cu catalysts and control *CO availability by regulating CO2 concentration and reaction rate. This strategy leads to a 1.6× improvement in the methane:H2 selectivity ratio compared to the best prior reports operating above 100 mA cm-2. We as a result achieve a CO2-to-methane Faradaic efficiency (FE) of (56 ± 2)% at a production rate of (112 ± 4) mA cm-2.

7.
J Immunol ; 206(9): 2015-2028, 2021 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-33820855

RESUMO

The cGAS-cyclic GMP-AMP (cGAMP)-stimulator of IFN genes (STING) pathway induces a powerful type I IFN (IFN-I) response and is a prime candidate for augmenting immunity in cancer immunotherapy and vaccines. IFN-I also has immune-regulatory functions manifested in several autoimmune diseases and is a first-line therapy for relapsing-remitting multiple sclerosis. However, it is only moderately effective and can induce adverse effects and neutralizing Abs in recipients. Targeting cGAMP in autoimmunity is unexplored and represents a challenge because of the intracellular location of its receptor, STING. We used microparticle (MP)-encapsulated cGAMP to increase cellular delivery, achieve dose sparing, and reduce potential toxicity. In the C57BL/6 experimental allergic encephalomyelitis (EAE) model, cGAMP encapsulated in MPs (cGAMP MPs) administered therapeutically protected mice from EAE in a STING-dependent fashion, whereas soluble cGAMP was ineffective. Protection was also observed in a relapsing-remitting model. Importantly, cGAMP MPs protected against EAE at the peak of disease and were more effective than rIFN-ß. Mechanistically, cGAMP MPs showed both IFN-I-dependent and -independent immunosuppressive effects. Furthermore, it induced the immunosuppressive cytokine IL-27 without requiring IFN-I. This augmented IL-10 expression through activated ERK and CREB. IL-27 and subsequent IL-10 were the most important cytokines to mitigate autoreactivity. Critically, cGAMP MPs promoted IFN-I as well as the immunoregulatory cytokines IL-27 and IL-10 in PBMCs from relapsing-remitting multiple sclerosis patients. Collectively, this study reveals a previously unappreciated immune-regulatory effect of cGAMP that can be harnessed to restrain T cell autoreactivity.


Assuntos
Micropartículas Derivadas de Células/imunologia , Encefalomielite Autoimune Experimental/imunologia , Interferon Tipo I/imunologia , Proteínas de Membrana/imunologia , Nucleotídeos Cíclicos/imunologia , Transdução de Sinais/imunologia , Animais , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Micropartículas Derivadas de Células/metabolismo , Células Cultivadas , Citocinas/imunologia , Citocinas/metabolismo , Encefalomielite Autoimune Experimental/metabolismo , Encefalomielite Autoimune Experimental/prevenção & controle , Feminino , Humanos , Interferon Tipo I/metabolismo , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Proteínas de Membrana/agonistas , Proteínas de Membrana/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos , Camundongos Knockout , Nucleotídeos Cíclicos/administração & dosagem , Nucleotídeos Cíclicos/metabolismo , Transdução de Sinais/efeitos dos fármacos
8.
Langmuir ; 37(6): 2146-2152, 2021 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-33534994

RESUMO

NaLnF4 nanoparticles (NPs) with lighter lanthanides (where Ln = La, Ce, Nd, or Pr) are more difficult to prepare than those with heavier lanthanides [Naduviledathu et al. Chem Mater., 2014, 26, 5689]. Our knowledge is weakest for NaLnF4 NPs with the lowest atomic mass lanthanides (Yan's group 1: La to Nd) and more advanced for group 2 (Sm to Tb) NaLnF4 NPs [Mai et al., J. Am. Chem. Soc., 2006, 128, 6426]. Here we focus on the synthesis of NaNdF4 NPs. We employed the high-temperature chemical coprecipitation method and explored the influence of a wide range of synthesis parameters (e.g., reaction time and temperature, precursor ratios (Na+/Nd3+ and F-/Nd3+), choice of a sodium precursor (Na-oleate or NaOH), and the amount of oleic acid) on the size and uniformity of the NPs obtained. We tried to identify "sweet spots" in the reaction space that led to uniform NaNdF4 NPs with sizes appropriate for mass tag applications in mass cytometry. We were able to obtain NPs with a variety of sizes in the range of 5-38 nm with several different shapes (e.g., polyhedra, spheres, and rods). XRD patterns recorded for aliquots collected at different reaction time intervals revealed that NaNdF4 nucleated in the cubic phase (α) and then transformed to the hexagonal phase (ß) as the reaction progressed up to 2 h. A very striking observation was that the NPs synthesized using NaOH as a reactant preferred to remain in the α-phase, and for a lower reaction temperature (285 °C), did not undergo a phase transformation to the ß-phase over 2 h of reaction time. Under similar experimental conditions, NPs prepared using Na-oleate exhibited an α → ß phase transformation. Nevertheless, NaNdF4 NPs prepared at a higher temperature (315 °C) using either of the Na+ precursors exhibited the α → ß phase transformation over time. This transition, however, appeared to be faster in the case of the NPs synthesized using Na-oleate. We found that, in many instances, syntheses carried out using Na-oleate produced more uniform NPs compared to those synthesized using NaOH. Under the conditions we employed for the Na-oleate precursor, the NPs initially formed were polydisperse spheres that evolved into irregular polyhedra and eventually formed more uniform rod-shaped NPs. The aspect ratio of the final NPs depended on the Na+/Nd3+ precursor ratio. High-resolution transmission electron micrographs and corresponding fast Fourier transform of the data provided information about the preferred growth direction of the NaNdF4 nanorods.

9.
Angew Chem Int Ed Engl ; 60(19): 10950-10956, 2021 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-33626229

RESUMO

One-dimensional (1D) and 2D structures by crystallization-driven self-assembly of block copolymers (BCPs) can form fascinating hierarchical structures through secondary self-assembly. But examples of 3D structures formed via hierarchical self-assembly are rare. Here we report seeded growth experiments in decane of a poly(ferrocenyldimethylsilane) BCP with an amphiphilic corona forming block in which lenticular platelets grow into classic spherulite-like uniform colloidally stable structures. These 3D objects are spherically symmetric on the exterior, but asymmetric near the core, where there is a more open structure consisting of sheaf-like leaves. The most remarkable aspect of these experiments is that growth stops at different stages of growth process, depending upon how much unimer is added in the seeded growth step. The system provides a model for studying spherulitic growth where real-time observations on their growth at different stages remains challenging.

10.
Methods ; 194: 30-36, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-33422676

RESUMO

CRISPR/Cas9-based genome editing has been widely used to evaluate target gene function in biomedical research. The CRISPR/Cas9 system can introduce gene knockout, knock-in and mutations with more ease than earlier generations of genome editing tools. Using CRISPR/Cas9-based genome editing, researchers have successfully modified the DNA of different immune components, including primary T cells, B cells, macrophages, and immune system progenitors, i.e. hematopoietic stem cells (HSCs), which are also known as Lin-Sca1 + Kit + cells (LSKs) in mice. We previously reported that the transplantation of HSCs with lentivirus-mediated CRISPR/Cas9-based genetic modifications into lethally irradiated congenic mice repopulated the ablated recipient immune system with the donor immune system. In this report, we efficiently manipulated CD40 expression in LSK cells using Cas9 RNP and demonstrated the functional impact in a colitis model. Compared to a virus-based strategy, the RNP approach has the potential to enable investigation of target gene biology in any mouse strain and eliminates the time and effort associated with virus production and infection. Therefore, in vivo RNP-based CRISPR/Cas9 gene editing of transplanted HSCs represents a promising new strategy for exploring gene function in the immune system of mice.


Assuntos
Sistemas CRISPR-Cas , Edição de Genes , Animais , Sistemas CRISPR-Cas/genética , Células-Tronco Hematopoéticas/metabolismo , Sistema Imunitário , Camundongos , Ribonucleoproteínas/genética , Ribonucleoproteínas/metabolismo
11.
Nano Lett ; 21(1): 437-444, 2021 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-33373247

RESUMO

Al2O3-graphene nanolayers are widely used within integrated micro/nanoelectronic systems; however, their lifetimes are largely limited by fracture both statically and dynamically. Here, we present a static and fatigue study of thin (1-11 nm) free-standing Al2O3-graphene nanolayers. A remarkable fatigue life of greater than one billion cycles was obtained for films <2.2 nm thick under large mean stress levels, which was up to 3 orders of magnitude longer than that of its thicker (11 nm) counterpart. A similar thickness dependency was also identified for the elastic and static fracture behavior, where the enhancement effect of graphene is prominent only within a thickness of ∼3.3 nm. Moreover, plastic deformation, manifested by viscous creep, was observed and appeared to be more substantial for thicker films. This study provides mechanistic insights on both the static and dynamic reliability of Al2O3-graphene nanolayers and can potentially guide the design of graphene-based devices.

12.
Science ; 370(6516)2020 10 30.
Artigo em Inglês | MEDLINE | ID: mdl-33122357

RESUMO

Ionizing radiation causes acute radiation syndrome, which leads to hematopoietic, gastrointestinal, and cerebrovascular injuries. We investigated a population of mice that recovered from high-dose radiation to live normal life spans. These "elite-survivors" harbored distinct gut microbiota that developed after radiation and protected against radiation-induced damage and death in both germ-free and conventionally housed recipients. Elevated abundances of members of the bacterial taxa Lachnospiraceae and Enterococcaceae were associated with postradiation restoration of hematopoiesis and gastrointestinal repair. These bacteria were also found to be more abundant in leukemia patients undergoing radiotherapy, who also displayed milder gastrointestinal dysfunction. In our study in mice, metabolomics revealed increased fecal concentrations of microbially derived propionate and tryptophan metabolites in elite-survivors. The administration of these metabolites caused long-term radioprotection, mitigation of hematopoietic and gastrointestinal syndromes, and a reduction in proinflammatory responses.


Assuntos
Síndrome Aguda da Radiação/microbiologia , Clostridiales/metabolismo , Enterococcaceae/metabolismo , Ácidos Graxos Voláteis/metabolismo , Microbioma Gastrointestinal , Proteção Radiológica , Triptofano/metabolismo , Síndrome Aguda da Radiação/prevenção & controle , Síndrome Aguda da Radiação/terapia , Animais , Ácidos Graxos Voláteis/uso terapêutico , Humanos , Metabolômica , Camundongos , Camundongos Endogâmicos C57BL , Sobreviventes
13.
Nat Commun ; 11(1): 2193, 2020 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-32366851

RESUMO

Innate immunity to nucleic acids forms the backbone for anti-viral immunity and several inflammatory diseases. Upon sensing cytosolic viral RNA, retinoic acid-inducible gene-I-like receptors (RLRs) interact with the mitochondrial antiviral signaling protein (MAVS) and activate TANK-binding kinase 1 (TBK1) to induce type I interferon (IFN-I). TRAF3-interacting protein 3 (TRAF3IP3, T3JAM) is essential for T and B cell development. It is also well-expressed by myeloid cells, where its role is unknown. Here we report that TRAF3IP3 suppresses cytosolic poly(I:C), 5'ppp-dsRNA, and vesicular stomatitis virus (VSV) triggers IFN-I expression in overexpression systems and Traf3ip3-/- primary myeloid cells. The mechanism of action is through the interaction of TRAF3IP3 with endogenous TRAF3 and TBK1. This leads to the degradative K48 ubiquitination of TBK1 via its K372 residue in a DTX4-dependent fashion. Mice with myeloid-specific gene deletion of Traf3ip3 have increased RNA virus-triggered IFN-I production and reduced susceptibility to virus. These results identify a function of TRAF3IP3 in the regulation of the host response to cytosolic viral RNA in myeloid cells.


Assuntos
Proteínas de Transporte/genética , Regulação da Expressão Gênica , Interferon Tipo I/genética , Proteínas de Membrana/genética , Células Mieloides/metabolismo , Proteínas Serina-Treonina Quinases/genética , RNA Viral/genética , Animais , Proteínas de Transporte/metabolismo , Linhagem Celular , Células Cultivadas , Chlorocebus aethiops , Citosol/metabolismo , Citosol/virologia , Células HEK293 , Células HeLa , Humanos , Interferon Tipo I/metabolismo , Células Jurkat , Lisina/genética , Lisina/metabolismo , Proteínas de Membrana/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Células Mieloides/virologia , Proteínas Serina-Treonina Quinases/metabolismo , RNA Viral/metabolismo , Células THP-1 , Ubiquitinação , Células Vero , Vírus da Estomatite Vesicular Indiana/genética , Vírus da Estomatite Vesicular Indiana/fisiologia
14.
Nat Mater ; 19(4): 405-411, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31959950

RESUMO

Materials can suffer mechanical fatigue when subjected to cyclic loading at stress levels much lower than the ultimate tensile strength, and understanding this behaviour is critical to evaluating long-term dynamic reliability. The fatigue life and damage mechanisms of two-dimensional (2D) materials, of interest for mechanical and electronic applications, are currently unknown. Here, we present a fatigue study of freestanding 2D materials, specifically graphene and graphene oxide (GO). Using atomic force microscopy, monolayer and few-layer graphene were found to exhibit a fatigue life of more than 109 cycles at a mean stress of 71 GPa and a stress range of 5.6 GPa, higher than any material reported so far. Fatigue failure in monolayer graphene is global and catastrophic without progressive damage, while molecular dynamics simulations reveal this is preceded by stress-mediated bond reconfigurations near defective sites. Conversely, functional groups in GO impart a local and progressive fatigue damage mechanism. This study not only provides fundamental insights into the fatigue enhancement behaviour of graphene-embedded nanocomposites, but also serves as a starting point for the dynamic reliability evaluation of other 2D materials.

15.
Nanoscale ; 11(40): 18730-18738, 2019 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-31591615

RESUMO

All-solid-state batteries (ASSBs) have attracted much attention due to their enhanced energy density and safety as compared to traditional liquid-based batteries. However, cyclic performance depreciates due to microcrack formation and propagation at the interface of the solid-state electrolytes (SSEs) and electrodes. Herein, we studied the elastic and fracture behavior of atomic layer deposition (ALD) synthesized glassy lithium phosphate (LPO) and lithium tantalate (LTO) thin films as promising candidates for SSEs. The mechanical behavior of ALD prepared SSE thin films with a thickness range of 5 nm to 30 nm over suspended single-layer graphene was studied using an atomic force microscope (AFM) film deflection technique. Scanning transmission electron microscopy (STEM) coupled with AFM was used for microstructural analysis. LTO films exhibited higher stiffness and higher fracture forces as compared to LPO films. Fracture in LTO films occurred directly under the indenter in a brittle fashion, while LPO films failed by a more complex fracture mechanism including significant plastic deformation prior to the onset of complete fracture. The results and methodology described in this work open a new window to identify the potential influence of SSEs mechanical performance on their operation in flexible ASSBs.

16.
J Exp Med ; 216(12): 2838-2853, 2019 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-31558613

RESUMO

The role of lipids in inflammasome activation remains underappreciated. The phospholipid, platelet-activating factor (PAF), exerts multiple physiological functions by binding to a G protein-coupled seven-transmembrane receptor (PAFR). PAF is associated with a number of inflammatory disorders, yet the molecular mechanism underlying its proinflammatory function remains to be fully elucidated. We show that multiple PAF isoforms and PAF-like lipids can activate the inflammasome, resulting in IL-1ß and IL-18 maturation. This is dependent on NLRP3, ASC, caspase-1, and NEK7, but not on NLRC4, NLRP1, NLRP6, AIM2, caspase-11, or GSDMD. Inflammasome activation by PAF also requires potassium efflux and calcium influx but not lysosomal cathepsin or mitochondrial reactive oxygen species. PAF exacerbates peritonitis partly through inflammasome activation, but PAFR is dispensable for PAF-induced inflammasome activation in vivo or in vitro. These findings reveal that PAF represents a damage-associated signal that activates the canonical inflammasome independently of PAFR and provides an explanation for the ineffectiveness of PAFR antagonist in blocking PAF-mediated inflammation in the clinic.


Assuntos
Inflamassomos/metabolismo , Quinases Relacionadas a NIMA/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Fator de Ativação de Plaquetas/metabolismo , Glicoproteínas da Membrana de Plaquetas/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Animais , Cálcio/metabolismo , Caspase 1/metabolismo , Furanos/farmacologia , Compostos Heterocíclicos de 4 ou mais Anéis , Humanos , Indenos , Interleucina-18/metabolismo , Interleucina-1beta/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Camundongos , Proteína 3 que Contém Domínio de Pirina da Família NLR/antagonistas & inibidores , Proteínas de Ligação a Fosfato/metabolismo , Potássio/metabolismo , Sulfonamidas/farmacologia , Sulfonas
17.
Phys Chem Chem Phys ; 21(32): 17880-17892, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31380540

RESUMO

Zeolites have recently attracted attention for upgrading renewable resources in the presence of liquid water phases; however, the stability of zeolites in the presence of liquid-phase water is not completely understood. Accordingly, the stability of the ZSM-5 framework and its acid sites was studied in the presence of water at temperatures ranging from 250 to 450 °C and at pressures sufficient to maintain a liquid or liquid-like state (25 MPa). Treated samples were analyzed for framework degradation and Al content and coordination using a variety of complementary techniques, including X-ray diffraction, electron microscopy, N2 sorption, 27Al and 29Si NMR spectroscopy, and several different types of infrared spectroscopy. These analyses indicate that the ZSM-5 framework retains >80% crystallinity at all conditions, and that 300-400 °C are the most aggressive. Decrystallization appears to initiate primarily at crystal surfaces and share many characteristics in common with alkali promoted desilication. Liquid water treatment promotes ZSM-5 dealumination, following a mechanism analogous to that observed under steaming conditions: initiation by Al-O hydrolysis, Al migration to the surface, and finally deposition as extra framework Al or possibly complete dissolution under some conditions. As with the framework, dealumination is most aggressive at 300-400 °C. Several models were evaluated to capture the non-Arrhenius effect of temperature on decrystallization and dealumination, the most successful of which included temperature dependent values of the water auto-ionization constant. These results can help interpretation of previous studies on ZSM-5 catalysis in hot liquid water and suggest future approaches to extend catalyst lifetime.

18.
PLoS Pathog ; 15(7): e1007847, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31306468

RESUMO

Salmonella exploit host-derived nitrate for growth in the lumen of the inflamed intestine. The generation of host-derived nitrate is dependent on Nos2, which encodes inducible nitric oxide synthase (iNOS), an enzyme that catalyzes nitric oxide (NO) production. However, the cellular sources of iNOS and, therefore, NO-derived nitrate used by Salmonella for growth in the lumen of the inflamed intestine remain unidentified. Here, we show that iNOS-producing inflammatory monocytes infiltrate ceca of mice infected with Salmonella. In addition, we show that inactivation of type-three secretion system (T3SS)-1 and T3SS-2 renders Salmonella unable to induce CC- chemokine receptor-2- and CC-chemokine ligand-2-dependent inflammatory monocyte recruitment. Furthermore, we show that the severity of the pathology of Salmonella- induced colitis as well as the nitrate-dependent growth of Salmonella in the lumen of the inflamed intestine are reduced in mice that lack Ccr2 and, therefore, inflammatory monocytes in the tissues. Thus, inflammatory monocytes provide a niche for Salmonella expansion in the lumen of the inflamed intestine.


Assuntos
Mucosa Intestinal/metabolismo , Mucosa Intestinal/microbiologia , Monócitos/metabolismo , Salmonella typhimurium/metabolismo , Salmonella typhimurium/patogenicidade , Animais , Quimiocina CCL2/deficiência , Quimiocina CCL2/genética , Quimiocina CCL2/metabolismo , Feminino , Interações entre Hospedeiro e Microrganismos/genética , Interações entre Hospedeiro e Microrganismos/fisiologia , Humanos , Inflamação/metabolismo , Inflamação/microbiologia , Inflamação/patologia , Mucosa Intestinal/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Modelos Biológicos , Monócitos/patologia , Óxido Nítrico Sintase Tipo II/metabolismo , Receptores CCR2/deficiência , Receptores CCR2/genética , Receptores CCR2/metabolismo , Salmonelose Animal/metabolismo , Salmonelose Animal/microbiologia , Salmonelose Animal/patologia , Salmonella typhimurium/genética , Sistemas de Secreção Tipo III/metabolismo
19.
Immunity ; 50(3): 591-599.e6, 2019 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-30893587

RESUMO

Immune suppression is a crucial component of immunoregulation and a subgroup of nucleotide-binding domain (NBD), leucine-rich repeat (LRR)-containing proteins (NLRs) attenuate innate immunity. How this inhibitory function is controlled is unknown. A key question is whether microbial ligands can regulate this inhibition. NLRC3 is a negative regulator that attenuates type I interferon (IFN-I) response by sequestering and attenuating stimulator of interferon genes (STING) activation. Here, we report that NLRC3 binds viral DNA and other nucleic acids through its LRR domain. DNA binding to NLRC3 increases its ATPase activity, and ATP-binding by NLRC3 diminishes its interaction with STING, thus licensing an IFN-I response. This work uncovers a mechanism wherein viral nucleic acid binding releases an inhibitory innate receptor from its target.


Assuntos
DNA Viral/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Interferon Tipo I/metabolismo , Proteínas de Membrana/metabolismo , Animais , Linhagem Celular , Linhagem Celular Tumoral , Células HEK293 , Células HeLa , Humanos , Imunidade Inata/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Ácidos Nucleicos/metabolismo , Ligação Proteica/imunologia
20.
Cell Host Microbe ; 25(4): 602-616.e7, 2019 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-30902577

RESUMO

Establishing the balance between positive and negative innate immune mechanisms is crucial for maintaining homeostasis. Here we uncover the regulatory crosstalk between two previously unlinked innate immune receptor families: RIG-I, an anti-viral cytosolic receptor activated type I interferon production, and NLR (nucleotide-binding domain, leucine repeat domain-containing protein). We show that NLRP12 dampens RIG-I-mediated immune signaling against RNA viruses by controlling RIG-I's association with its adaptor MAVS. The nucleotide-binding domain of NLRP12 interacts with the ubiquitin ligase TRIM25 to prevent TRIM25-mediated, Lys63-linked ubiquitination and activation of RIG-I. NLRP12 also enhances RNF125-mediated, Lys48-linked degradative ubiquitination of RIG-I. Vesicular stomatitis virus (VSV) infection downregulates NLRP12 expression to allow RIG-I activation. Myeloid-cell-specific Nlrp12-deficient mice display a heightened interferon and TNF response and are more resistant to VSV infection. These results indicate that NLRP12 functions as a checkpoint for anti-viral RIG-I activation.


Assuntos
Proteína DEAD-box 58/imunologia , Proteínas de Ligação a DNA/imunologia , Peptídeos e Proteínas de Sinalização Intracelular/imunologia , Infecções por Vírus de RNA/imunologia , Vírus de RNA/fisiologia , Fatores de Transcrição/imunologia , Animais , Proteína DEAD-box 58/genética , Proteínas de Ligação a DNA/genética , Feminino , Humanos , Interferons/genética , Interferons/imunologia , Peptídeos e Proteínas de Sinalização Intracelular/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ligação Proteica , Infecções por Vírus de RNA/genética , Infecções por Vírus de RNA/virologia , Vírus de RNA/genética , Fatores de Transcrição/genética , Ubiquitinação
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