ABSTRACT
The execution of shock following high dose E. coli lipopolysaccharide (LPS) or bacterial sepsis in mice required pro-apoptotic caspase-8 in addition to pro-pyroptotic caspase-11 and gasdermin D. Hematopoietic cells produced MyD88- and TRIF-dependent inflammatory cytokines sufficient to initiate shock without any contribution from caspase-8 or caspase-11. Both proteases had to be present to support tumor necrosis factor- and interferon-ß-dependent tissue injury first observed in the small intestine and later in spleen and thymus. Caspase-11 enhanced the activation of caspase-8 and extrinsic cell death machinery within the lower small intestine. Neither caspase-8 nor caspase-11 was individually sufficient for shock. Both caspases collaborated to amplify inflammatory signals associated with tissue damage. Therefore, combined pyroptotic and apoptotic signaling mediated endotoxemia independently of RIPK1 kinase activity and RIPK3 function. These observations bring to light the relevance of tissue compartmentalization to disease processes in vivo where cytokines act in parallel to execute diverse cell death pathways.
Subject(s)
Caspase 8/metabolism , Caspases/metabolism , Escherichia coli Infections/enzymology , Escherichia coli Infections/physiopathology , Shock, Septic/enzymology , Shock, Septic/physiopathology , Animals , Apoptosis , Apoptosis Regulatory Proteins/metabolism , Caspase 8/genetics , Caspases/genetics , Caspases, Initiator , Cells, Cultured , Female , Inflammation/metabolism , Inflammation/pathology , Interferon Regulatory Factor-3/genetics , Interferon-beta/blood , Interferon-beta/metabolism , Intestine, Small/pathology , Intracellular Signaling Peptides and Proteins , Lipopolysaccharides/toxicity , Male , Mice, Inbred C57BL , Mice, Knockout , Phosphate-Binding Proteins , Receptor-Interacting Protein Serine-Threonine Kinases/genetics , Receptor-Interacting Protein Serine-Threonine Kinases/metabolism , Signal Transduction , Spleen/pathology , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Tumor Necrosis Factor-alpha/blood , Tumor Necrosis Factor-alpha/metabolismABSTRACT
Cytochromes P450 (P450s or CYPs) are the most important phase I metabolic enzymes in the human body and are responsible for metabolizing â¼75% of the clinically used drugs. P450-mediated metabolism is also closely associated with the formation of toxic metabolites and drug-drug interactions. Therefore, it is of high importance to predict if a compound is the substrate of a given P450 in the early stage of drug development. In this study, we built the multitask learning models to simultaneously predict the substrates of five major drug-metabolizing P450 enzymes, namely, CYP3A4, 2C9, 2C19, 2D6, and 1A2, based on the collected substrate data sets. Compared to the single-task model and conventional machine learning models, the multitask fingerprints and graph neural networks model achieved superior performance with the average AUC values of 90.8% on the test set. Notably, the multitask model demonstrated its good performance on the small amount of substrate data sets such as CYP1A2, 2C9, and 2C19. In addition, the Shapley additive explanation and the attention mechanism were used to reveal specific substructures associated with P450 substrates, which were further confirmed and complemented by the substructure mining tool and the literature.
ABSTRACT
A novel slightly halophilic, aerobic, and Gram-stain-negative strain, designated as CH-27T, was isolated during a bacterial resource investigation of intertidal sediment collected from Xiaoshi Island in Weihai, PR China. Cells of strain CH-27T were rod-shaped with widths of 0.3-0.6 µm and lengths of 2.0-11.0 µm. Strain CH-27T grew optimally at 37â°C, pH 7.0 and with 2.0â% (w/v) NaCl. Catalase activity was weakly positive and oxidase activity was positive. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CH-27T was most related to Marinihelvus fidelis KCTC 92639T (93.6â%), followed by Wenzhouxiangella marina MCCC 1K00261T (92.0â%). Based on genome comparisons between strain CH-27T and M. fidelis KCTC 92639T, the average amino acid identity was 63.6â% and the percentage of conserved proteins was 48.3â%. The major cellular fatty acid of strain CH-27T (≥10â%) was iso-C15â:â0 and the sole respiratory quinone was quinone-8. The polar lipids were phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, and aminophospholipid. The DNA G+C content was 62.7âmol%. Based on comprehensive analysis of its phylogenetic, physiological, biochemical, and chemotaxonomic characteristics, strain CH-27T represents a novel species in a novel genus, for which the name Elongatibacter sediminis gen. nov., sp.nov. is proposed. The type strain is CH-27T (=MCCC 1H00480T=KCTC 8011T).
Subject(s)
Bacterial Typing Techniques , Base Composition , DNA, Bacterial , Fatty Acids , Geologic Sediments , Phylogeny , RNA, Ribosomal, 16S , Sequence Analysis, DNA , Fatty Acids/chemistry , Geologic Sediments/microbiology , China , RNA, Ribosomal, 16S/genetics , DNA, Bacterial/genetics , Genome, Bacterial , Phospholipids/chemistryABSTRACT
Cytochrome P450 3A4 (CYP3A4) is one of the most important drug-metabolizing enzymes in the human body and is well known for its complicated, atypical kinetic characteristics. The existence of multiple ligand-binding sites in CYP3A4 has been widely recognized as being capable of interfering with the active pocket through allosteric effects. The identification of ligand-binding sites other than the canonical active site above the heme is especially important for understanding the atypical kinetic characteristics of CYP3A4 and the intriguing association between the ligand and the receptor. In this study, we first employed mixed-solvent molecular dynamics (MixMD) simulations coupled with the online computational predictive tools to explore potential ligand-binding sites in CYP3A4. The MixMD approach demonstrates better performance in dealing with the receptor flexibility compared with other computational tools. From the sites identified by MixMD, we then picked out multiple sites for further exploration using ensemble docking and conventional molecular dynamics (cMD) simulations. Our results indicate that three extra sites are suitable for ligand binding in CYP3A4, including one experimentally confirmed site and two novel sites.
Subject(s)
Cytochrome P-450 CYP3A , Molecular Dynamics Simulation , Solvents , Cytochrome P-450 CYP3A/chemistry , Cytochrome P-450 CYP3A/metabolism , Ligands , Binding Sites , Solvents/chemistry , Humans , Molecular Docking Simulation , Protein Binding , Protein ConformationABSTRACT
Artificial enzymes with high stability, adjustable catalytic activity, controllable preparation, and good reproducibility have been widely studied. Noble metal nanozymes, particularly gold nanoparticles (Au NPs), exhibit good catalytic activity, but their stability is poor. In this study, zeolitic imidazolate framework-8 (ZIF-8) was used as a carrier for Au NPs, thus improving the utilization efficiency and conservation stability of the nanozymes. A ZIF-8/Au nanocomposite with peroxidase activity and a raspberry-shaped structure was synthesized. In the assay, ZIF-8/Au catalyzed the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to a blue product oxidized TMB (oxTMB). Glutathione (GSH) selectively inhibited this reaction, with a detection limit of 0.28 µM and linear range of 0.5-60 µM. Using the photo and chromaticity analysis functions, we developed a portable analysis method using a smartphone equipped with a camera module as a detection terminal for a wide range of rapid screening techniques for GSH. Preparation of raspberry-shaped ZIF-8/Au improved the catalytic activity of Au NPs and good results were demonstrated in serum, which suggests their promising application under physiological conditions.
Subject(s)
Glutathione , Gold , Limit of Detection , Metal Nanoparticles , Gold/chemistry , Glutathione/chemistry , Glutathione/analysis , Glutathione/blood , Metal Nanoparticles/chemistry , Metal-Organic Frameworks/chemistry , Colorimetry/methods , Peroxidase/chemistry , Peroxidase/metabolism , Zeolites/chemistry , Humans , Smartphone , Oxidation-Reduction , Catalysis , Benzidines/chemistryABSTRACT
Cytochrome P450 (CYP) enzymes are involved in the metabolism of approximately 75% of marketed drugs. Inhibition of the major drug-metabolizing P450s could alter drug metabolism and lead to undesirable drug-drug interactions. Therefore, it is of great significance to explore the inhibition of P450s in drug discovery. Currently, machine learning including deep learning algorithms has been widely used for constructing in silico models for the prediction of P450 inhibition. These models exhibited varying predictive performance depending on the use of machine learning algorithms and molecular representations. This leads to the difficulty in the selection of appropriate models for practical use. In this study, we systematically evaluated the conventional machine learning and deep learning models for three major P450 enzymes, CYP3A4, CYP2D6, and CYP2C9 from several perspectives, such as algorithms, molecular representation, and data partitioning strategies. Our results showed that the XGBoost and CatBoost algorithms coupled with the combined fingerprint/physicochemical descriptor features exhibited the best performance with Area Under Curve (AUC) of 0.92, while the deep learning models were generally inferior to the conventional machine learning models (average AUC reached 0.89) on the same test sets. We also found that data volume and sampling strategy had a minor effect on model performance. We anticipate that these results are helpful for the selection of molecular representations and machine learning/deep learning algorithms in the P450 model construction and the future model development of P450 inhibition.
Subject(s)
Machine Learning , Humans , Cytochrome P-450 CYP3A/metabolism , Cytochrome P-450 CYP2C9/metabolism , Cytochrome P-450 CYP2D6/metabolism , Algorithms , Deep Learning , Computer Simulation , Cytochrome P-450 CYP2C9 Inhibitors/pharmacology , Cytochrome P-450 CYP2D6 Inhibitors/pharmacology , Cytochrome P-450 CYP3A Inhibitors/pharmacology , Cytochrome P-450 Enzyme Inhibitors/pharmacologyABSTRACT
Porphyrins easily aggregate due to unfavorable π-π accumulation, causing luminescent quenching in the aqueous phase and subsequently reducing luminescent efficiency. It is a feasible way to immobilize porphyrin molecules through metal-organic framework materials (MOFs). In this study, 5,10,15,20-tetrakis (4-carboxyphenyl) porphyrin (TCPP) was introduced into the metal-organic skeleton (PCN-224) as a ligand. The result showed that the electrochemiluminescence (ECL) and photoluminescence (PL) efficiency of the MOF skeleton was 8.2 and 6.5 times higher than TCPP, respectively. Impressively, the periodic distribution of porphyrin molecules in the MOF framework can overcome the bottleneck of porphyrin aggregation, resulting in the organic ligand TCPP participating in the electron transfer reaction. Herein, based on the PCN-224, a sandwich-type ECL immunosensor was constructed for the determination of cardiac troponin I (cTnI). It provided sensitive detection of cTnI in the range of 1 fg/mL to 10 ng/mL with a detection limit of 0.34 fg/mL. This work not only innovatively exploited a disaggregation ECL (DIECL) strategy via the crystalline framework of MOF to enhance the PL and ECL efficiency of porphyrin but also provided a promising ECL platform for the ultrasensitive monitoring of cTnI.
Subject(s)
Luminescent Measurements , Glycosides/chemistry , Metal-Organic Frameworks/chemistry , Luminescent Measurements/methods , Troponin I/chemistry , Limit of Detection , Biosensing Techniques/methods , Immunoassay/methodsABSTRACT
Confinement effects in highly porous nanostructures can effectively adjust the selectivity and kinetics of electrochemical reactions, which can boost the methanol oxidation reaction (MOR). In this work, carbonized ZIF-8-confined hollow PtCo nanospheres (PtCo@carbonized ZIF-8) were fabricated using a facile strategy. A monodisperse confined region was successfully prepared, and the dispersion of the PtCo nanoparticles (NPs) could be precisely regulated, allowing for the effective tuning of the confined region. Thus, the precise regulation of the catalytic reaction was achieved. Importantly, hollow PtCo NPs were prepared using a method based on the Kirkendall effect, and their forming mechanism was systematically investigated. Because of the confinement effects of carbonized zeolitic imidazolate framework-8 (ZIF-8), the crystal and electronic structures of the PtCo NPs were able to be effectively tuned. Our electrochemical results show that PtCo@carbonized ZIF-8 composites manifest a higher mass activity (1.4 A mgPt-1) and better stability compared to commercial Pt/C.
ABSTRACT
Cytochrome P450 3A4 (CYP3A4) is one of the major drug-metabolizing enzymes in the human body and is responsible for the metabolism of â¼50% of clinically used drugs. Therefore, the identification of the compound's sites of metabolism (SOMs) mediated by CYP3A4 is of utmost importance in the early stage of drug discovery and development. Herein, docking-based approaches incorporating geometric features were used for SOMs prediction of CYP3A4 substrates. The cross-docking poses of a relatively large data set containing 474 substrates were analyzed in depth, and a widely observed geometric pattern called the close proximity of SOMs was derived from the poses. On the basis of the close proximity, several structure-based models have been constructed, which demonstrated better performance than those structure-based models using the criterion of Fe-SOM distance. For further improving the prediction performance, the structure-based models were also combined with the well-known ligand-based model SMARTCyp. One combined model exhibited good performance on the SOMs prediction of an external substrate set containing kinase inhibitors, PROTACs, approved drugs, and some lead compounds.
Subject(s)
Cytochrome P-450 CYP3A , Drug Discovery , Humans , Cytochrome P-450 CYP3A/metabolism , Protein BindingABSTRACT
PURPOSE: To investigate the factors influencing the volume of the olfactory bulb (OB) in patients with post-viral olfactory dysfunction (PVOD). METHODS: We collected 92 olfactory bulb volumes from patients with PVOD who underwent a sinus computed tomographic and magnetic resonance imaging (MRI) scan of the head and collected clinical information including gender, age, disease course, minimal cross-sectional area, nasal airway resistance, and olfactory function. OB volume was measured in MRI and the scans were evaluated according to the Lund-Mackay (LM) scoring system. RESULTS: Male patients with PVOD had a larger OB volume (ß = 0.284, P < 0.05). OB volume was smaller in patients with a longer course of olfactory dysfunction (ß = - 0.254, P < 0.05). According to the LM scoring system, patients with a higher anterior ethmoidal sinus score had smaller OB volume (ß = - 0.476, P < 0.05). CONCLUSIONS: The study revealed that gender, disease course, and the score of anterior ethmoidal sinusitis can affect the OB volume in patients with PVOD.
Subject(s)
Olfaction Disorders , Paranasal Sinuses , Humans , Male , Olfactory Bulb/pathology , Smell , Nose , Magnetic Resonance Imaging , Olfaction Disorders/diagnostic imaging , Olfaction Disorders/etiology , Olfaction Disorders/pathologyABSTRACT
The precisely modulated synthesis of programmable light-emitting materials remains a challenge. To address this challenge, we construct four tetraphenylethylene-based supramolecular architectures (SA, SB, SC, and SD), revealing that they exhibit higher electrochemiluminescence (ECL) intensities and efficiencies than the tetraphenylethylene monomer and can be classified as highly efficient and precisely modulated intramolecular aggregation-induced electrochemiluminescence (PI-AIECL) systems. The best-performing system (SD) shows a high ECL cathodic efficiency exceeding that of the benchmark tris(2,2'-bipyridyl)ruthenium(II) chloride in aqueous solution by nearly six-fold. The electrochemical characterization of these architectures in an organic solvent provides deeper mechanistic insights, revealing that SD features the lowest electrochemical band gap. Density functional theory calculations indicate that the band gap of the guest ligand in the SD structure is the smallest and most closely matched to that of the host scaffold. Finally, the SD system is used to realize ECL-based cysteine detection (detection limit=14.4â nM) in real samples. Thus, this study not only provides a precisely modulated supramolecular strategy allowing chromophores to be controllably regulated on a molecular scale, but also inspires the programmable synthesis of high-performance aggregation-induced electrochemiluminescence emitters.
ABSTRACT
The intriguing aggregation-induced emission has recently been applied in the electrochemiluminescence, called aggregation-induced electrochemiluminescence (AIE-ECL), which is conducive to solving the water insolubility and aggregation-caused quenching for most organic luminescence probes. However, AIE-ECL still has the problems of low luminous efficiency and limited practical application. In this work, we disclosed the AIE-ECL properties of 1,2,3-triaryl-substituted indenes containing rigid structures. Experimental and theoretical investigations demonstrated that such a rigid structure could significantly enhance the aromaticity and stability and thereby the luminescence performance of these indenes. Moreover, according to the finding of hydrogen/deuterium exchange for active hydrogen in indene under electrical excitation, ultrasensitive detection for D2O in H2O was realized by such an indene-based AIE-ECL system. Our research not only provided an attractive strategy to enhance the luminescence property for an AIE-active luminophore but also established a superior sensor toward D2O.
Subject(s)
Biosensing Techniques , Indenes , Deuterium , Electrochemical Techniques , Luminescent Measurements , Water/chemistryABSTRACT
Photoelectrochemical (PEC) water splitting technology is a promising strategy toward producing sustainable hydrogen fuel. However, it is an essential bottleneck to reduce severe charge recombination for the improvement of PEC performance. Construction of heterojunction systems, such as Z-scheme and type II heterojunctions, could efficiently boost charge separation, whereas the mechanism of charge separation is still ambiguous. We describe herein a charge transfer system designed with Bi2WO6/Bi2S3 (BWO/BS) as a prototype. In this system, Au nanoparticles act as charge relays to engineer a charge transfer pathway, and the obtained BWO/Au/BS photoanode achieves a remarkable photocurrent density of 0.094 mA cm-2 at 1.23 V versus reversible hydrogen electrode (vs RHE), over approximately 1.2 and 2.3 times larger than those of BWO/BS/Au and BWO, exhibiting long-term photostability. More importantly, scanning photoelectrochemical microscopy (SPECM) and intensity-modulated photocurrent spectroscopy (IMPS) studies are performed to in situ-capture the photogenerated hole during the PEC process. Operando analysis reveals that the Z-scheme BWO/Au/BS system (1.33 × 10-2 cm s-1) exhibits higher charge transfer kinetics compared to the type II BWO/BS/Au heterostructure (0.85 × 10-2 cm s-1) while efficiently suppressing charge recombination for optimized PEC activity. Note that this smart strategy can also be extended to other semiconductor-based photoanodes such as BiVO4. Our study offers an effective pathway for the rational design of highly efficient charge separation for solar conversion based on water splitting.
ABSTRACT
The magnitude of CD8 T cell responses against viruses is checked by the balance of proliferation and death. Caspase-8 (CASP8) has the potential to influence response characteristics through initiation of apoptosis, suppression of necroptosis, and modulation of cell death-independent signal transduction. Mice deficient in CASP8 and RIPK3 (Casp8-/-Ripk3-/- ) mount enhanced peak CD8 T cell levels against the natural mouse pathogen murine cytomegalovirus (MCMV) or the human pathogen herpes simplex virus-1 compared with littermate control RIPK3-deficient or WT C57BL/6 mice, suggesting an impact of CASP8 on the magnitude of antiviral CD8 T cell expansion and not on contraction. The higher peak response to MCMV in Casp8-/-Ripk3-/- mice resulted from accumulation of greater numbers of terminally differentiated KLRG1hi effector CD8 T cell subsets. Antiviral Casp8-/-Ripk3-/- T cells exhibited enhanced proliferation when splenocytes were transferred into WT recipient mice. Thus, cell-autonomous CASP8 normally restricts CD8 T cell proliferation following T cell receptor activation in response to foreign antigen. Memory inflation is a hallmark quality of the T cell response to cytomegalovirus infection. Surprisingly, MCMV-specific memory inflation was not sustained long-term in Casp8-/-Ripk3-/- mice even though these mice retained immunity to secondary challenge. In addition, the accumulation of abnormal B220+CD3+ T cells in these viable CASP8-deficient mice was reduced by chronic MCMV infection. Combined, these data brings to light the cell death-independent role of CASP8 during CD8 T cell expansion in mice lacking the confounding impact of RIPK3-mediated necroptosis.
Subject(s)
CD8-Positive T-Lymphocytes/immunology , Caspase 8/genetics , Cytomegalovirus Infections/immunology , Muromegalovirus/immunology , Receptor-Interacting Protein Serine-Threonine Kinases/genetics , T-Lymphocyte Subsets/immunology , Adoptive Transfer , Animals , CD8-Positive T-Lymphocytes/virology , Caspase 8/immunology , Cell Proliferation , Cytomegalovirus Infections/genetics , Cytomegalovirus Infections/virology , Female , Gene Expression Regulation , Herpes Simplex/genetics , Herpes Simplex/immunology , Herpes Simplex/virology , Herpesvirus 1, Human/immunology , Herpesvirus 1, Human/pathogenicity , Immunologic Memory , Lectins, C-Type/genetics , Lectins, C-Type/immunology , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Muromegalovirus/pathogenicity , Receptor-Interacting Protein Serine-Threonine Kinases/deficiency , Receptor-Interacting Protein Serine-Threonine Kinases/immunology , Receptors, Antigen, T-Cell/genetics , Receptors, Antigen, T-Cell/immunology , Receptors, Immunologic/genetics , Receptors, Immunologic/immunology , Signal Transduction , T-Lymphocyte Subsets/virologyABSTRACT
Caspase-8 (Casp8)-mediated signaling triggers extrinsic apoptosis while suppressing receptor-interacting protein kinase (RIPK) 3-dependent necroptosis. Although Casp8 is dispensable for the development of innate and adaptive immune compartments in mice, the importance of this proapoptotic protease in the orchestration of immune response to pathogens remains to be fully explored. In this study, Casp8-/-Ripk3-/- C57BL/6 mice show robust innate and adaptive immune responses to the natural mouse pathogen, murine CMV. When young, these mice lack lpr-like lymphoid hyperplasia and accumulation of either B220 + CD3+ or B220-CD3+CD4+ and CD8+ T cells with increased numbers of immature myeloid cells that are evident in older mice. Dendritic cell activation and cytokine production drive both NK and T cell responses to control viral infection in these mice, suggesting that Casp8 is dispensable to the generation of antiviral host defense. Curiously, NK and T cell expansion is amplified, with greater numbers observed by 7 d postinfection compared with either Casp8+/-Ripk3-/- or wild type (Casp8+/+Ripk3+/+ ) littermate controls. Casp8 and RIPK3 are natural targets of virus-encoded cell death suppressors that prevent infected cell apoptosis and necroptosis, respectively. It is clear from the current studies that the initiation of innate immunity and the execution of cytotoxic lymphocyte functions are all preserved despite the absence of Casp8 in responding cells. Thus, Casp8 and RIPK3 signaling is completely dispensable to the generation of immunity against this natural herpesvirus infection, although the pathways driven by these initiators serve as a crucial first line for host defense within virus-infected cells.
Subject(s)
Caspase 8/genetics , Dendritic Cells/immunology , Herpesviridae Infections/immunology , Muromegalovirus/physiology , Receptor-Interacting Protein Serine-Threonine Kinases/metabolism , Adaptive Immunity , Animals , Antigens, Viral/immunology , Apoptosis , Dendritic Cells/virology , Humans , Immunity, Innate , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Knockout , Necrosis , Receptor-Interacting Protein Serine-Threonine Kinases/genetics , Signal TransductionABSTRACT
The complex interplay between caspase-8 and receptor-interacting protein (RIP) kinase RIP 3 (RIPK3) driving extrinsic apoptosis and necroptosis is not fully understood. Murine cytomegalovirus triggers both apoptosis and necroptosis in infected cells; however, encoded inhibitors of caspase-8 activity (M36) and RIP3 signaling (M45) suppress these antiviral responses. Here, we report that this virus activates caspase-8 in macrophages to trigger apoptosis that gives rise to secondary necroptosis. Infection with double-mutant ΔM36/M45mutRHIM virus reveals a signaling pattern in which caspase-8 activates caspase-3 to drive apoptosis with subsequent RIP3-dependent activation of mixed lineage kinase domain-like (MLKL) leading to necroptosis. This combined cell death signaling is highly inflammatory, greater than either apoptosis induced by ΔM36 or necroptosis induced by M45mutRHIM virus. IL-6 production by macrophages is dramatically increased during double-mutant virus infection and correlates with faster antiviral responses in the host. Collaboratively, M36 and M45 target caspase-8 and RIP3 pathways together to suppress this proinflammatory cell death. This study reveals the effect of antiviral programmed cell death pathways on inflammation, shows that caspase-8 activation may go hand-in-hand with necroptosis in macrophages, and revises current understanding of independent and collaborative functions of M36 and M45 in blocking apoptotic and necroptotic cell death responses.
Subject(s)
Apoptosis , Herpesviridae Infections/veterinary , Muromegalovirus/metabolism , Ribonucleotide Reductases/metabolism , Rodent Diseases/physiopathology , Viral Proteins/metabolism , Animals , Caspase 8/genetics , Caspase 8/immunology , Herpesviridae Infections/immunology , Herpesviridae Infections/physiopathology , Herpesviridae Infections/virology , Host-Pathogen Interactions , Mice , Muromegalovirus/classification , Muromegalovirus/genetics , Receptor-Interacting Protein Serine-Threonine Kinases/genetics , Receptor-Interacting Protein Serine-Threonine Kinases/immunology , Ribonucleotide Reductases/genetics , Rodent Diseases/genetics , Rodent Diseases/immunology , Rodent Diseases/virology , Viral Proteins/geneticsABSTRACT
Caspase-8 (CASP8) impacts antiviral immunity in expected as well as unexpected ways. Mice with combined deficiency in CASP8 and RIPK3 cannot support extrinsic apoptosis or RIPK3-dependent programmed necrosis, enabling studies of CASP8 function without complications of unleashed necroptosis. These extrinsic cell death pathways are naturally targeted by murine cytomegalovirus (MCMV)-encoded cell death suppressors, showing they are key to cell-autonomous host defense. Remarkably, Casp8-/-Ripk3-/-, Ripk1-/-Casp8-/-Ripk3-/- and Casp8-/-Ripk3K51A/K51A mice mount robust antiviral T cell responses to control MCMV infection. Studies in Casp8-/-Ripk3-/- mice show that CASP8 restrains expansion of MCMV-specific natural killer (NK) and CD8 T cells without compromising contraction or immune memory. Infected Casp8-/-Ripk3-/- or Casp8-/-Ripk3K51A/K51A mice have higher levels of virus-specific NK cells and CD8 T cells compared to matched RIPK3-deficient littermates or WT mice. CASP8, likely acting downstream of Fas death receptor, dampens proliferation of CD8 T cells during expansion. Importantly, contraction proceeds unimpaired in the absence of extrinsic death pathways owing to intact Bim-dependent (intrinsic) apoptosis. CD8 T cell memory develops in Casp8-/-Ripk3-/- mice, but memory inflation characteristic of MCMV infection is not sustained in the absence of CASP8 function. Despite this, Casp8-/-Ripk3-/- mice are immune to secondary challenge. Interferon (IFN)γ is recognized as a key cytokine for adaptive immune control of MCMV. Ifngr-/-Casp8-/-Ripk3-/- mice exhibit increased lifelong persistence in salivary glands as well as lungs compared to Ifngr-/- and Casp8-/-Ripk3-/- mice. Thus, mice deficient in CASP8 and RIPK3 are more dependent on IFNγ mechanisms for sustained T cell immune control of MCMV. Overall, appropriate NK- and T cell immunity to MCMV is dependent on host CASP8 function independent of RIPK3-regulated pathways.
Subject(s)
Caspase 8/metabolism , Cytomegalovirus Infections/immunology , Killer Cells, Natural/immunology , Muromegalovirus/growth & development , Muromegalovirus/immunology , T-Lymphocytes/immunology , Animals , Disease Models, Animal , Mice , Mice, KnockoutABSTRACT
Natural killer (NK) cells provide important host defense against herpesvirus infections and influence subsequent T cell control of replication and maintenance of latency. NK cells exhibit phases of expansion, contraction and memory formation in response to the natural mouse pathogen murine cytomegalovirus (MCMV). Innate and adaptive immune responses are tightly regulated in mammals to avoid excess tissue damage while preventing acute and chronic viral disease and assuring resistance to reinfection. Caspase (CASP)8 is an autoactivating aspartate-specific cysteine protease that initiates extrinsic apoptosis and prevents receptor interacting protein (RIP) kinase (RIPK)1-RIPK3-driven necroptosis. CASP8 also promotes death-independent signal transduction. All of these activities make contributions to inflammation. Here, we demonstrate that CASP8 restricts NK cell expansion during MCMV infection but does not influence NK memory. Casp8-/-Ripk3-/- mice mount higher NK response levels than Casp8+/-Ripk3-/- littermate controls or WT C57BL/6 J mice, indicating that RIPK3 deficiency alone does not contribute to NK response patterns. MCMV m157-responsive Ly49H+ NK cells support increased expansion of both Ly49H- NK cells and CD8 T cells in Casp8-/-Ripk3-/- mice. Surprisingly, hyperaccumulation of NK cells depends on the pronecrotic kinase RIPK1. Ripk1-/-Casp8-/-Ripk3-/- mice fail to show the enhanced expansion of lymphocytes observed in Casp8-/-Ripk3-/- mice even though development and homeostasis are preserved in uninfected Ripk1-/-Casp8-/-Ripk3-/- mice. Thus, CASP8 naturally regulates the magnitude of NK cell responses in response to infection where strong activation signals depend on another key regulator of death signaling, RIPK1. In addition, the strong NK cell response promotes survival of effector CD8 T cells during their expansion. Thus, hyperaccumulation of NK cells and crosstalk with T cells becomes amplified in the absence of extrinsic cell death machinery.
Subject(s)
Caspase 8/metabolism , Cytomegalovirus Infections/immunology , Killer Cells, Natural/immunology , Muromegalovirus/growth & development , Muromegalovirus/immunology , Animals , Disease Models, Animal , Mice , Mice, Inbred C57BLABSTRACT
BACKGROUND: Intrahepatic cholangiocarcinoma (ICC) is a highly aggressive tumor of the bile duct, and a significant public health problem in East Asia, where it is associated with infection by the parasite Opisthorchis viverrini. ICC is often detected at an advanced stage and with a poor prognosis, making a biomarker for early detection a priority. METHODS: We have comprehensively profiled miRNA expression levels in ICC tumor tissue using small RNA-Seq and validated these profiles using quantitative PCR on matched plasma samples. RESULTS: Distinct miRNA profiles were associated with increasing histological differentiation of ICC tumor tissue. We also observed that histologically normal tissue adjacent to ICC tumor displayed miRNA expression profiles more similar to tumor than liver tissue from healthy donors. In plasma samples, an eight-miRNA signature associated with ICC, regardless of the degree of histological differentiation of its matched tissue, forming the basis of a circulating miRNA-based biomarker for ICC. CONCLUSIONS: The association of unique miRNA profiles with different ICC subtypes suggests the involvement of specific miRNAs during ICC tumor progression. In plasma, an eight-miRNA signature associated with ICC could form the foundation of an accessible (plasma-based) miRNA-based biomarker for the early detection of ICC.
Subject(s)
Bile Duct Neoplasms/blood , Biomarkers/blood , Cholangiocarcinoma/blood , MicroRNAs/blood , Animals , Bile Duct Neoplasms/genetics , Bile Duct Neoplasms/microbiology , Bile Duct Neoplasms/pathology , Cholangiocarcinoma/genetics , Cholangiocarcinoma/microbiology , Cholangiocarcinoma/pathology , Female , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Humans , MicroRNAs/genetics , MicroRNAs/isolation & purification , Middle Aged , Molecular Sequence Annotation , Opisthorchis/pathogenicity , PrognosisABSTRACT
Chronic rhinosinusitis (CRS) is believed to be the result of an exaggerated reaction to fungi in the nasal mucosa, and topical amphotericin B (AMB) is a commonly used treatment. The purpose of this study was to perform a meta-analysis of high-quality comparative studies to examine the efficacy of topical AMB for the treatment of CRS. A search was conducted of Medline, Cochrane, EMBASE, and ISI Web of Knowledge until December 31, 2013 using combinations of the search terms chronic rhinosinusitis, human, treatment, antibiotics, nasal irrigation, nebulized, nasal lavage, sinonasal rinses, and antimicrobials. Inclusion criteria were (1) comparative studies, (2) a diagnosis of CRS or chronic sinusitis, and (3) the intervention was a topical antifungal. The primary outcome measure was quality of life (QOL), and the secondary was nasal endoscopy score. Of 235 article initially identified, five randomized controlled trials were included in the meta-analysis. Analysis of four studies with complete QOL data found no difference between treatment and placebo groups [standard difference in means 0.78, 95 % confidence interval (CI) -0.25 to 1.81, P = 0.138]. Analysis of four studies with complete nasal endoscopy score data found no difference between the treatment and placebo groups (standard difference in means 0.34, 95 % CI -0.08 to 0.76, P = 0.117). AMB is not more effective than placebo in improving QOL or nasal endoscopy scores in patients with CRS.