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Immunology
Mesenchymal stem cell-derived factors: Immuno-modulatory effects and therapeutic potential
Jul 18, 2017   BioFactors (Oxford, England)
Volarevic V, Gazdic M, Simovic Markovic B, Jovicic N, Djonov V, Arsenijevic N
Mesenchymal stem cell-derived factors: Immuno-modulatory effects and therapeutic potential
Jul 18, 2017
BioFactors (Oxford, England)
Stem cell-based therapy is considered to be a new hope in transplantation medicine. Among stem cells, mesenchymal stem cells (MSCs) are, due to their differentiation and immuno-modulatory characteristics, the most commonly used as therapeutic agents in the treatment of immune-mediated diseases. MSCs migrate to the site of inflammation and modulate immune response. The capacity of MSC to alter phenotype and function of immune cells are largely due to the production of soluble factors which expression varies depending on the pathologic condition to which MSCs are exposed. Under inflammatory conditions, MSCs-derived factors suppress both innate and adaptive immunity by attenuating maturation and capacity for antigen presentation of dendritic cells, by inducing polarization of macrophages towards alternative phenotype, by inhibiting activation and proliferation of T and B lymphocytes and by reducing cytotoxicity of NK and NKT cells. In this review, we emphasized current findings regarding immuno-modulatory effects of MSC-derived factors and emphasize their potential in the therapy of immune-mediated diseases. © 2017 BioFactors, 2017. © 2017 International Union of Biochemistry and Molecular Biology.
Novel role of surfactant protein A in bacterial sinusitis
Jul 20, 2017   International Forum Of Allergy & Rhinology
Noutsios GT, Willis AL, Ledford JG, Chang EH
Novel role of surfactant protein A in bacterial sinusitis
Jul 20, 2017
International Forum Of Allergy & Rhinology
Chronic rhinosinusitis (CRS) is a common inflammatory disorder of the upper airway characterized by chronic inflammation and significant sinonasal remodeling. CRS is comprised of 2 major subgroups, based on whether polyps are present or absent. In some cases, it is characterized by colonization with opportunistic pathogens such as Pseudomonas aeruginosa (PA), Staphylococcus aureus, and other bacteria. The innate immune system of the sinonasal epithelium is the first line of defense against inhaled pathogens. Surfactant protein A (SP-A) is a member of the collectin family secreted by the airway epithelia and plays a critical role in airway innate immunity, as it can aggregate bacteria. We hypothesized that SP-A plays a role in bacterial CRS. Air-liquid interface (ALI) cultures of nasal epithelial cells were derived from human ex-vivo healthy and CRS sinus tissues (n = 26) and challenged with PA. SP-A levels were measured with western blot and quantitative reverse transcript-polymerase chain reaction (qRT-PCR) in ALI and sinus tissues. We determined that SP-A: (i) mRNA and protein levels are increased significantly in CRS tissues compared with healthy sinuses; (ii) although primarily expressed in the lung, it is also synthesized and expressed in sinonasal epithelia; (ii) is expressed in the sinuses of an SP-A humanized transgenic mouse but not in SP-A knockout mice; (iv) mRNA levels are upregulated significantly during PA challenge, but protein levels are downregulated 4 hours postchallenge and upregulated at 12 hours. Our data suggest that SP-A is expressed in the sinuses and that it plays a role in the sinus innate immune responses during bacterial infections. © 2017 ARS-AAOA, LLC.
β-Glucan Size Controls Dectin-1-Mediated Immune Responses in Human Dendritic Cells by Regulating IL-1β Production
Jul 24, 2017   Frontiers In Immunology
Elder MJ, Webster SJ, Chee R, Williams DL, Hill Gaston JS, Goodall JC
β-Glucan Size Controls Dectin-1-Mediated Immune Responses in Human Dendritic Cells by Regulating IL-1β Production
Jul 24, 2017
Frontiers In Immunology
Dectin-1/CLEC7A is a pattern recognition receptor that recognizes β-1,3 glucans, and its stimulation initiates signaling events characterized by the production of inflammatory cytokines from human dendritic cells (DCs) required for antifungal immunity. β-glucans differ greatly in size, structure, and ability to activate effector immune responses from DC; as such, small particulate β-glucans are thought to be poor activators of innate immunity. We show that β-glucan particle size is a critical factor contributing to the secretion of cytokines from human DC; large β-glucan-stimulated DC generate significantly more IL-1β, IL-6, and IL-23 compared to those stimulated with the smaller β-glucans. In marked contrast, the secretion of TSLP and CCL22 were found to be insensitive to β-glucan particle size. Furthermore, we show that the capacity to induce phagocytosis, and the relative IL-1β production determined by β-glucan size, regulates the composition of the cytokine milieu generated from DC. This suggests that β-glucan particle size is critically important in orchestrating the nature of the immune response to fungi.
Old and new adjuvants
Jul 22, 2017   Current Opinion In Immunology
McKee AS, Marrack P
Old and new adjuvants
Jul 22, 2017
Current Opinion In Immunology
Adjuvants have been deliberately added to vaccines since the 1920's when alum was discovered to boost antibody responses, leading to better protection. The first adjuvants were discovered by accident and were used in the safer but less immunogenic subunit vaccines, supposedly by providing an antigen depot to extend antigen presentation. Since that time, much has been discovered about how these adjuvants impact cells at the tissue site to activate innate immune responses, mobilize dendritic cells and drive adaptive immunity. New approaches to vaccine construction for infectious diseases that have so far not been well addressed by conventional vaccines often attempt to induce antibodies, polyfunctional CD4+ T cells and CD8+ CTLs. The discovery of pattern recognition receptors and ligands that drive desired T cell responses has led to development of novel adjuvant strategies using immunomodulatory agents to direct appropriate immune responses. Copyright © 2017 Elsevier Ltd. All rights reserved.
The effect of aspartate supplementation on the microbial composition and innate immunity on mice
Jul 22, 2017   Amino Acids
Bin P, Liu S, Chen S, Zeng Z, Huang R, Yin Y, Liu G
The effect of aspartate supplementation on the microbial composition and innate immunity on mice
Jul 22, 2017
Amino Acids
The study was conducted to investigate the changes of intestinal microbiota composition and innate immunity with different dietary dosages of aspartate (Asp) supplementation. Thirty-six female ICR mice were divided randomly to four groups and thereafter fed the basal diets (controls) or those supplemented with additional 0.5, 1.0 and 2.0% aspartate. After 2 week feeding, microbial composition in ileum and feces, gene expression of pro-inflammatory cytokine, and innate immune factors in ileum were determined. The ratio of Firmicutes: Bacteroidetes in ileum and feces decreased in 0.5 and 1.0% Asp-supplemented groups, whereas this ratio increased in feces in 2.0% Asp-supplemented group. Meanwhile, the gene expression of IL-17 and IFN-γ in ileum decreased in 1.0% Asp-supplemented group; the gene expression in ileum of Muc2 decreased in 0.5 and 1.0% Asp-supplemented groups. Dietary supplementation with 2.0% Asp enhanced the expression of pIgR and Crp1 as compared to the other three groups. The results indicated that dietary 1.0% Asp supplementation lowers the ratio of Firmicutes:Bacteroidetes, which affects the innate immunity by decreasing the gene expression of IL-17, IFN-γ, and Muc2 in ileum.
Mechanisms of NLRP1 mediated autoinflammatory disease in humans and mice
Jul 22, 2017   Journal Of Molecular Biology
Yu CH, Moecking J, Geyer M, Masters SL
Mechanisms of NLRP1 mediated autoinflammatory disease in humans and mice
Jul 22, 2017
Journal Of Molecular Biology
NLRP1 was the first NLR protein described to form an inflammasome, recruiting ASC to activate caspase-1, which processes interleukin-1β and interleukin-18 to their active form. A wealth of new genetic information has now redefined our understanding of this innate immune sensor. Specifically, rare loss-of-function variants in the N-terminal pyrin domain (PYD) indicate that this part of NLRP1 is autoinhibitory, and normally acts to prevent a familial autoinflammatory skin disease associated with cancer. In the absence of a ligand to trigger human NLRP1, these mutations have now confirmed the requirement of NLRP1 autolytic cleavage within the FIIND domain, which had previously been implicated in NLRP1 activation. Autolytic cleavage generates a C-terminal fragment of NLRP1 containing the CARD domain which then forms an ASC dependent inflammasome. The CARD domain as an inflammasome linker is consistent with the observation that under some conditions, particularly for mouse NLRP1, caspase-1 can be engaged directly, and although it is no longer processed, it is still capable of producing mature IL-1β. Additional rare variants in a linker region between the LRR and FIIND domains of NLRP1 also cause autoinflammatory disease in both humans and mice. This new genetic information is likely to provide for more mechanistic insight in the years to come, contributing to our understanding of how NLRP1 functions as an innate immune sensor of infection, and predisposes to autoimmune or autoinflammatory diseases. Copyright © 2017. Published by Elsevier Ltd.
Molecular, structural, and functional comparison of N lobe and C lobe of the transferrin from rock bream, Oplegnathus fasciatus, with respect to its immune response
Jul 22, 2017   Fish & Shellfish Immunology
Perera NCN, Godahewa GI, Hwang JY, Kwon MG, Hwang SD, Lee J
Molecular, structural, and functional comparison of N lobe and C lobe of the transferrin from rock bream, Oplegnathus fasciatus, with respect to its immune response
Jul 22, 2017
Fish & Shellfish Immunology
The iron-withholding strategy of innate immunity is an effective antimicrobial defense mechanism that combats microbial infection by depriving microorganisms of Fe3+, which is important for their growth and propagation. Transferrins (Tfs) are a group of iron-binding proteins that exert their antimicrobial function through Fe3+ sequestration. The current study describes both structural and functional characteristics of a transferrin ortholog from rock bream Oplegnathus fasciatus (RbTf). The RbTf cDNA possesses an open reading frame (ORF) of 2079 bp encoding 693 amino acids. It has a molecular mass of approximately 74 kDa and an isoelectric point of 5.4. In silico analysis revealed that RbTf has two conserved domains: N-terminal domain and C-terminal domain. Pairwise homology analysis and phylogenetic analysis revealed that RbTf shared the highest identity (82.6%) with Dicentrarchus labrax Tf. According to the genomic analysis, RbTf possesses 17 exons and 16 introns, similar to the other orthologs. Here, we cloned the N terminal and C terminal domains of RbTf to evaluate their distinct functional features. Results obtained through the CAS (chrome azurol S) assay confirmed the iron-binding ability of the RbTf, and it was further determined that the iron-binding ability of rRbTfN was higher than that of rRbTfC. The antimicrobial functions of the rRbTfN and the rRbTfC were confirmed via the iron-dependent bacterial growth inhibition assay. Tissue distribution profiling revealed a ubiquitous expression with intense expression in the liver. Temporal assessment revealed that RbTf increased after stimulation of LPS, Edwardsiella tarda, and Streptococcus iniae post injection (p.i.). These findings demonstrated that RbTf is an important antimicrobial protein that can combat bacterial pathogens. Copyright © 2017. Published by Elsevier Ltd.
Antiviral Immunity and Circular RNA: No End in Sight
Jul 21, 2017   Molecular Cell
Cadena C, Hur S
Antiviral Immunity and Circular RNA: No End in Sight
Jul 21, 2017
Molecular Cell
In this issue of Molecular Cell, two papers by Chen et al. (2017) and Li et al. (2017) describe new insights into circRNA biogenesis and function, connecting circRNAs to innate immune pathways. Copyright © 2017 Elsevier Inc. All rights reserved.
PD-1 Checkpoint Blockade in Combination with an mTOR Inhibitor Restrains Hepatocellular Carcinoma Growth Induced by Hepatoma Cell-Intrinsic PD-1
Jul 21, 2017   Hepatology (Baltimore, Md.)
Li H, Li X, Liu S, Guo L, Zhang B, Zhang J, Ye Q
PD-1 Checkpoint Blockade in Combination with an mTOR Inhibitor Restrains Hepatocellular Carcinoma Growth Induced by Hepatoma Cell-Intrinsic PD-1
Jul 21, 2017
Hepatology (Baltimore, Md.)
Inhibitors of PD-1 administered as single agents have resulted in durable tumor regression in advanced cancer patients. However, only a minority of cancer patients respond to anti PD-1 immunotherapy. Here, we show that PD-1 expression in hepatocellular carcinoma (HCC) promotes tumor growth independently of adaptive immunity. Knockdown of PD-1 suppress tumor growth, whereas PD-1 overexpression enhances tumorigenesis in immunodeficient xenografted mice. Mechanistically, PD-1 binds the downstream mTOR effectors eukaryotic initiation factor 4E (eIF4E) and ribosomal protein S6 (S6), thus promoting their phosphorylation. Moreover, combining mTOR inhibition with anti-PD-1 antibody treatment results in more durable and synergistic tumor regression than either single agent alone, each of which presents only modest efficacy. Therefore, targeting mTOR pathways in combination with PD-1 may result in increased antitumor efficacy in cancer patients. This article is protected by copyright. All rights reserved. © 2017 by the American Association for the Study of Liver Diseases.
Contributions of Interleukin-33 and TSLP in a papain-soaked contact lens-induced mouse conjunctival inflammation model
Jul 21, 2017   Immunity, Inflammation And Disease
Sugita J, Asada Y, Ishida W, Iwamoto S, Sudo K,   . . . . . .   , Ebihara N, Saito H, Kubo M, Nakae S, Matsuda A
Contributions of Interleukin-33 and TSLP in a papain-soaked contact lens-induced mouse conjunctival inflammation model
Jul 21, 2017
Immunity, Inflammation And Disease
Pathological changes of severe chronic allergic conjunctivitis are driven not only via acquired immunity but also via innate immunity. Type 2 immune response-initiating cytokines may play some roles as innate immunity-dependent components of the ocular surface inflammation. To investigate the involvement of type 2 immune response-initiating cytokines in innate immunity-dependent, papain-induced conjunctival inflammation model using IL-25-, IL-33-, and TSLP receptor (TSLPR)-knockout (KO) mice with reference to basophils and ILC2. Papain-soaked contact lenses (papain-CLs) were installed in the conjunctival sacs of C57BL/6-IL-25 KO, IL-33 KO, TSLPR KO, Rag2 KO, Bas-TRECK, and wild-type mice and their eyes were sampled at day 5. The eosinophil and basophil infiltration in papain-CL model was evaluated histologically and cytokine expression was examined. To clarify the roles of basophils and ILC2, basophil/ILC2-depletion experiments were carried out. Papain-induced conjunctival inflammation exhibited eosinophil infiltration and upregulation of Th2 cytokine expression. Reduction of eosinophil and basophil infiltration and attenuated Th2 cytokine expression were observed in the papain-CL model using IL-33 KO and TSLPR KO mice. Depletion of basophils or ILC2s in the conjunctivae of the papain-CL model reduced eosinophil infiltration. Innate immunity-driven type 2 immune responses of the ocular surface are dependent on IL-33, TSLP, basophils, and ILC2. These components may be possible therapeutic targets for refractory allergic keratoconjunctivitis. © 2017 The Authors. Immunity, Inflammation and Disease Published by John Wiley & Sons Ltd.
A Methodology for Comprehensive Analysis of Toll-Like Receptor Signaling in Macrophages
Jul 21, 2017   Methods In Molecular Biology (Clifton, N.J.)
Koppenol-Raab M, Nita-Lazar A
A Methodology for Comprehensive Analysis of Toll-Like Receptor Signaling in Macrophages
Jul 21, 2017
Methods In Molecular Biology (Clifton, N.J.)
A combination of high-throughput, multiplexed, quantitative methods with computational modeling and statistical approaches is required to obtain system-level understanding of biological function. Mass spectrometry (MS)-based proteomics has emerged as a preferred tool for the analysis of changes in protein abundance and their post-translational modification (PTM) levels at a global scale, comparable with genomic experiments and generating data suitable for use in mathematical modeling of signaling pathways. Here we describe a set of parallel bottom-up proteomic approaches to detect and quantify the global protein changes in total intracellular proteins, their phosphorylation, and the proteins released by active and passive secretion or shedding mechanisms (referred to as the secretome as reviewed in Makridakis and Vlahou, J Proteome 73:2291-2305, 2010) in response to the stimulation of Toll-like receptors (TLRs) with specific ligands in cultured macrophages. The method includes protocols for metabolic labeling of cells (SILAC: stable isotope labeling by amino acids in cell culture; Ong et al., Mol Cell Proteomics 1:376-386, 2002), ligand stimulation, cell lysis and media collection, in-gel and in-solution modification and digestion of proteins, phosphopeptide enrichment for phosphoproteomics, and LC-MS/MS analysis. With these methods, we can not only reliably quantify the relative changes in the TLR signaling components (Sjoelund et al., J Proteome Res 13:5185-5197, 2014) but also use the data as constraints for mathematical modeling.
Structures of the CRISPR genome integration complex
Jul 21, 2017   Science (New York, N.Y.)
Wright AV, Liu JJ, Knott GJ, Doxzen KW, Nogales E, Doudna JA
Structures of the CRISPR genome integration complex
Jul 21, 2017
Science (New York, N.Y.)
CRISPR-Cas systems depend on the Cas1-Cas2 integrase to capture and integrate short foreign DNA fragments into the CRISPR locus, enabling adaptation to new viruses. We present crystal structures of Cas1-Cas2 bound to both donor and target DNA in intermediate and product integration complexes, as well as a cryo-electron microscopy structure of the full CRISPR locus integration complex including the accessory protein Integration Host Factor (IHF). The structures show unexpectedly that indirect sequence recognition dictates integration site selection by favoring deformation of the repeat and the flanking sequences. IHF binding bends the DNA sharply, bringing an upstream recognition motif into contact with Cas1 to increase both the specificity and efficiency of integration. These results explain how the Cas1-Cas2 CRISPR integrase recognizes a sequence-dependent DNA structure to ensure site-selective CRISPR array expansion during the initial step of bacterial adaptive immunity. Copyright © 2017, American Association for the Advancement of Science.
An integrative genomics approach identifies novel pathways that influence candidaemia susceptibility
Jul 20, 2017   PloS One
Matzaraki V, Gresnigt MS, Jaeger M, Ricaño-Ponce I, Johnson MD,   . . . . . .   , Jonkers I, Li Y, Wijmenga C, Netea MG, Kumar V
An integrative genomics approach identifies novel pathways that influence candidaemia susceptibility
Jul 20, 2017
PloS One
Candidaemia is a bloodstream infection caused by Candida species that primarily affects specific groups of at-risk patients. Because only small candidaemia patient cohorts are available, classical genome wide association cannot be used to identify Candida susceptibility genes. Therefore, we have applied an integrative genomics approach to identify novel susceptibility genes and pathways for candidaemia. Candida-induced transcriptome changes in human primary leukocytes were assessed by RNA sequencing. Genetic susceptibility to candidaemia was assessed using the Illumina immunochip platform for genotyping of a cohort of 217 patients. We then integrated genetics data with gene-expression profiles, Candida-induced cytokine production capacity, and circulating concentrations of cytokines. Based on the intersection of transcriptome pathways and genomic data, we prioritized 31 candidate genes for candidaemia susceptibility. This group of genes was enriched with genes involved in inflammation, innate immunity, complement, and hemostasis. We then validated the role of MAP3K8 in cytokine regulation in response to Candida stimulation. Here, we present a new framework for the identification of susceptibility genes for infectious diseases that uses an unbiased, hypothesis-free, systems genetics approach. By applying this approach to candidaemia, we identified novel susceptibility genes and pathways for candidaemia, and future studies should assess their potential as therapeutic targets.
Bidirectional communication between the Aryl hydrocarbon Receptor (AhR) and the microbiome tunes host metabolism
Jul 19, 2017   NPJ Biofilms And Microbiomes
Korecka A, Dona A, Lahiri S, Tett AJ, Al-Asmakh M,   . . . . . .   , Narbad A, Holmes E, Nicholson J, Arulampalam V, Pettersson S
Bidirectional communication between the Aryl hydrocarbon Receptor (AhR) and the microbiome tunes host metabolism
Jul 19, 2017
NPJ Biofilms And Microbiomes
The ligand-induced transcription factor, aryl hydrocarbon receptor (AhR) is known for its capacity to tune adaptive immunity and xenobiotic metabolism-biological properties subject to regulation by the indigenous microbiome. The objective of this study was to probe the postulated microbiome-AhR crosstalk and whether such an axis could influence metabolic homeostasis of the host. Utilising a systems-biology approach combining in-depth 1H-NMR-based metabonomics (plasma, liver and skeletal muscle) with microbiome profiling (small intestine, colon and faeces) of AhR knockout (AhR-/-) and wild-type (AhR+/+) mice, we assessed AhR function in host metabolism. Microbiome metabolites such as short-chain fatty acids were found to regulate AhR and its target genes in liver and intestine. The AhR signalling pathway, in turn, was able to influence microbiome composition in the small intestine as evident from microbiota profiling of the AhR+/+ and AhR-/- mice fed with diet enriched with a specific AhR ligand or diet depleted of any known AhR ligands. The AhR-/- mice also displayed increased levels of corticosterol and alanine in serum. In addition, activation of gluconeogenic genes in the AhR-/- mice was indicative of on-going metabolic stress. Reduced levels of ketone bodies and reduced expression of genes involved in fatty acid metabolism in the liver further underscored this observation. Interestingly, exposing AhR-/- mice to a high-fat diet showed resilience to glucose intolerance. Our data suggest the existence of a bidirectional AhR-microbiome axis, which influences host metabolic pathways.
Live cell visualization of gasdermin D-driven pyroptotic cell death
Jul 20, 2017   The Journal Of Biological Chemistry
Rathkey JK, Benson BL, Chirieleison SM, Yang J, Xiao TS, Dubyak GR, Huang AY, Abbott DW
Live cell visualization of gasdermin D-driven pyroptotic cell death
Jul 20, 2017
The Journal Of Biological Chemistry
Pyroptosis is a form of cell death important in defenses against pathogens, but which can also result in a potent and sometimes pathological inflammatory response. During pyroptosis, gasdermin D (GSDMD), the pore-forming effector protein, is cleaved, forms oligomers, and inserts into the membranes of the cell, resulting in rapid cell death. However, the potent cell death induction caused by GSDMD has complicated our ability to understand the biology of this protein. Studies aimed at visualizing GSDMD have relied on expression of GSDMD fragments in epithelial cell lines that naturally lack GSDMD expression and also lack the proteases necessary to cleave GSDMD. In this work, we performed mutagenesis and molecular modeling to strategically place tags and fluorescent proteins within GSDMD that support native pyroptosis and facilitate live-cell imaging of pyroptotic cell death. Here, we demonstrate that these fusion proteins are cleaved by caspases-1 and 11 at Asp-276. Mutations that disrupted the predicted p30-p20 autoinhibitory interface resulted in GSDMD aggregation, supporting the oligomerizing activity of these mutations. Furthermore, we show that these novel GSDMD fusions execute inflammasome-dependent pyroptotic cell death in response to multiple stimuli and allow for visualization of the morphological changes associated with pyroptotic cell death in real time. This work therefore provides new tools that not only expand the molecular understanding of pyroptosis, but also enable its direct visualization. Copyright © 2017, The American Society for Biochemistry and Molecular Biology.
MD2 Blockage Protects Obesity-Induced Vascular Remodeling via Activating AMPK/Nrf2
Jul 20, 2017   Obesity (Silver Spring, Md.)
Wang L, Han J, Shan P, You S, Chen X, Jin Y, Wang J, Huang W, Wang Y, Liang G
MD2 Blockage Protects Obesity-Induced Vascular Remodeling via Activating AMPK/Nrf2
Jul 20, 2017
Obesity (Silver Spring, Md.)
Obesity and increased free fatty acid (FFA) levels are tightly linked with vascular oxidative stress and remodeling. Myeloid differentiation 2 (MD2), an important protein in innate immunity, is requisite for endotoxin lipopolysaccharide responsiveness. This study shows that palmitic acid (PA) also bonds to MD2, initiating cardiac inflammatory injury. However, it is not clear whether MD2 plays a role in noninflammatory systems such as obesity- and FFA-related oxidative stress involved in vascular remodeling and injury. The aim of this study is to examine whether MD2 participates in reactive oxygen species increase and vascular remodeling. Male MD2-/- mice and wild-type littermates with a C57BL/6 background were fed a high-fat diet (HFD) to establish obesity-induced vascular remodeling. Rat aortic endothelial cells (RAECs) and vascular smooth muscle cells (VSMCs) were treated with PA to induce oxidative stress and injury. In vivo, MD2 deficiency significantly reduced HFD-induced vascular oxidative stress, fibrosis, and remodeling, accompanied with AMP-activated kinase (AMPK) activation and nuclear factor erythroid (Nrf2) upregulation. In VSMCs and RAECs, inhibition of MD2 by neutralizing monoclonal antibody to MD2 or small interfering RNA knockdown significantly activated the AMPK/Nrf2-signaling pathway and reduced PA-induced oxidative stress and cell injury. It was demonstrated that the deletion or inhibition of MD2 protects against HFD/FFA-induced vascular oxidative stress and remodeling by activating the AMPK/Nrf2-signaling pathway. © 2017 The Obesity Society.
A time-resolved molecular map of the macrophage response to VSV infection
Jul 20, 2017   NPJ Systems Biology And Applications
Kandasamy RK, Vladimer GI, Snijder B, Müller AC, Rebsamen M,   . . . . . .   , Cleary C, Kralovics R, Colinge J, Bennett KL, Superti-Furga G
A time-resolved molecular map of the macrophage response to VSV infection
Jul 20, 2017
NPJ Systems Biology And Applications
Studying the relationship between virus infection and cellular response is paradigmatic for our understanding of how perturbation changes biological systems. Immune response, in this context is a complex yet evolutionarily adapted and robust cellular change, and is experimentally amenable to molecular analysis. To visualize the full cellular response to virus infection, we performed temporal transcriptomics, proteomics, and phosphoproteomics analysis of vesicular stomatitis virus (VSV)-infected mouse macrophages. This enabled the understanding of how infection-induced changes in host gene and protein expression are coordinated with post-translational modifications by cells in time to best measure and control the infection process. The vast and complex molecular changes measured could be decomposed in a limited number of clusters within each category (transcripts, proteins, and protein phosphorylation) each with own kinetic parameter and characteristic pathways/processes, suggesting multiple regulatory options in the overall sensing and homeostatic program. Altogether, the data underscored a prevalent executive function to phosphorylation. Resolution of the molecular events affecting the RIG-I pathway, central to viral recognition, reveals that phosphorylation of the key innate immunity adaptor mitochondrial antiviral-signaling protein (MAVS) on S328/S330 is necessary for activation of type-I interferon and nuclear factor κ B (NFκB) pathways. To further understand the hierarchical relationships, we analyzed kinase-substrate relationships and found RAF1 and, to a lesser extent, ARAF to be inhibiting VSV replication and necessary for NFκB activation, and AKT2, but not AKT1, to be supporting VSV replication. Integrated analysis using the omics data revealed co-regulation of transmembrane transporters including SLC7A11, which was subsequently validated as a host factor in the VSV replication. The data sets are predicted to greatly empower future studies on the functional organization of the response of macrophages to viral challenges.
Interleukin-36β provides protection against HSV-1 infection, but does not modulate initiation of adaptive immune responses
Jul 20, 2017   Scientific Reports
Milora KA, Uppalapati SR, Sanmiguel JC, Zou W, Jensen LE
Interleukin-36β provides protection against HSV-1 infection, but does not modulate initiation of adaptive immune responses
Jul 20, 2017
Scientific Reports
Interleukin-36 (IL-36) represents three cytokines, IL-36α, IL-36β and IL-36γ, which bind to the same receptor, IL-1RL2; however, their physiological function(s) remain poorly understood. Here, the role of IL-36 in immunity against HSV-1 was examined using the flank skin infection mouse model. Expression analyses revealed increased levels of IL-36α and IL-36β mRNA in infected skin, while constitutive IL-36γ levels remained largely unchanged. In human keratinocytes, IL-36α mRNA was induced by HSV-1, while IL-1β and TNFα increased all three IL-36 mRNAs. The dominant alternative splice variant of human IL-36β mRNA was isoform 2, which is the ortholog of the known mouse IL-36β mRNA. Mice deficient in IL-36β, but not IL-36α or IL-36γ, succumbed more frequently to HSV-1 infection than wild type mice. Furthermore, IL-36β-/- mice developed larger zosteriform skin lesions along infected neurons. Levels of HSV-1 specific antibodies, CD8+ cells and IFNγ-producing CD4+ cells were statistically equal in wild type and IL-36β-/- mice, suggesting similar initiation of adaptive immunity in the two strains. This correlated with the time at which HSV-1 genome and mRNA levels in primary skin lesions started to decline in both wild type and IL-36β-/- mice. Our data indicate that IL-36β has previously unrecognized functions protective against HSV-1 infection.
The Lysine Acetyltransferase GCN5 Is Required for iNKT Cell Development through EGR2 Acetylation
Jul 20, 2017   Cell Reports
Wang Y, Yun C, Gao B, Xu Y, Zhang Y, Wang Y, Kong Q, Zhao F, Wang CR, Dent SYR, Wang J, Xu X, Li HB, Fang D
The Lysine Acetyltransferase GCN5 Is Required for iNKT Cell Development through EGR2 Acetylation
Jul 20, 2017
Cell Reports
The development of CD1d-restricted invariant natural killer T (iNKT) cells, a population that is critical for both innate and adaptive immunity, is regulated by multiple transcription factors, but the molecular mechanisms underlying how the transcriptional activation of these factors are regulated during iNKT development remain largely unknown. We found that the histone acetyltransferase general control non-derepressible 5 (GCN5) is essential for iNKT cell development during the maturation stage. GCN5 deficiency blocked iNKT cell development in a cell-intrinsic manner. At the molecular level, GCN5 is a specific lysine acetyltransferase of early growth responsive gene 2 (EGR2), a transcription factor required for iNKT cell development. GCN5-mediated acetylation positively regulated EGR2 transcriptional activity, and both genetic and pharmacological GCN5 suppression specifically inhibited the transcription of EGR2 target genes in iNKT cells, including Runx1, promyelocytic leukemia zinc finger protein (PLZF), interleukin (IL)-2Rb, and T-bet. Therefore, our study revealed GCN5-mediated EGR2 acetylation as a molecular mechanism that regulates iNKT development. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.
Peroxisome-Mediated Metabolism Is Required for Immune Response to Microbial Infection
Jul 20, 2017   Immunity
Di Cara F, Sheshachalam A, Braverman NE, Rachubinski RA, Simmonds AJ
Peroxisome-Mediated Metabolism Is Required for Immune Response to Microbial Infection
Jul 20, 2017
Immunity
The innate immune response is critical for animal homeostasis and is conserved from invertebrates to vertebrates. This response depends on specialized cells that recognize, internalize, and destroy microbial invaders through phagocytosis. This is coupled to autonomous or non-autonomous cellular signaling via reactive oxygen species (ROS) and cytokine production. Lipids are known signaling factors in this process, as the acute phase response of macrophages is accompanied by systemic lipid changes that help resolve inflammation. We found that peroxisomes, membrane-enclosed organelles central to lipid metabolism and ROS turnover, were necessary for the engulfment of bacteria by Drosophila and mouse macrophages. Peroxisomes were also required for resolution of bacterial infection through canonical innate immune signaling. Reduced peroxisome function impaired the turnover of the oxidative burst necessary to fight infection. This impaired response to bacterial challenge affected cell and organism survival and revealed a previously unknown requirement for peroxisomes in phagocytosis and innate immunity. Copyright © 2017 Elsevier Inc. All rights reserved.
The P2X7 Receptor in Infection and Inflammation
Jul 20, 2017   Immunity
Di Virgilio F, Dal Ben D, Sarti AC, Giuliani AL, Falzoni S
The P2X7 Receptor in Infection and Inflammation
Jul 20, 2017
Immunity
Adenosine triphosphate (ATP) accumulates at sites of tissue injury and inflammation. Effects of extracellular ATP are mediated by plasma membrane receptors named P2 receptors (P2Rs). The P2R most involved in inflammation and immunity is the P2X7 receptor (P2X7R), expressed by virtually all cells of innate and adaptive immunity. P2X7R mediates NLRP3 inflammasome activation, cytokine and chemokine release, T lymphocyte survival and differentiation, transcription factor activation, and cell death. Ten human P2RX7 gene splice variants and several SNPs that produce complex haplotypes are known. The P2X7R is a potent stimulant of inflammation and immunity and a promoter of cancer cell growth. This makes P2X7R an appealing target for anti-inflammatory and anti-cancer therapy. However, an in-depth knowledge of its structure and of the associated signal transduction mechanisms is needed for an effective therapeutic development. Copyright © 2017 Elsevier Inc. All rights reserved.
The monogenic autoinflammatory diseases define new pathways in human innate immunity and inflammation
Jul 19, 2017   Nature Immunology Add nature.com free-link Cancel
Manthiram K, Zhou Q, Aksentijevich I, Kastner DL
The monogenic autoinflammatory diseases define new pathways in human innate immunity and inflammation
Jul 19, 2017
Nature Immunology
Autoinflammatory diseases were first recognized nearly 20 years ago as distinct clinical and immunological entities caused by dysregulation in the innate immune system. Since then, advances in genomic techniques have led to the identification of new monogenic disorders and their corresponding signaling pathways. Here we review these monogenic autoinflammatory diseases, ranging from periodic fever syndromes caused by dysregulated inflammasome-mediated production of the cytokine IL-1β to disorders arising from perturbations in signaling by the transcription factor NF-κB, ubiquitination, cytokine signaling, protein folding, type I interferon production and complement activation, and we further examine their molecular mechanisms. We also explore the overlap among autoinflammation, autoimmunity and immunodeficiency, and pose a series of unanswered questions that are expected to be central in autoinflammatory disease research in the coming decade.
A guiding map for inflammation
Jul 19, 2017   Nature Immunology Add nature.com free-link Cancel
Netea MG, Balkwill F, Chonchol M, Cominelli F, Donath MY,   . . . . . .   , Steer CJ, Tilg H, van der Meer JWM, van de Veerdonk FL, Dinarello CA
A guiding map for inflammation
Jul 19, 2017
Nature Immunology
Biologists, physicians and immunologists have contributed to the understanding of the cellular participants and biological pathways involved in inflammation. Here, we provide a general guide to the cellular and humoral contributors to inflammation as well as to the pathways that characterize inflammation in specific organs and tissues.
Type III CRISPR-Cas systems produce cyclic oligoadenylate second messengers
Jul 19, 2017   Nature Add nature.com free-link Cancel
Niewoehner O, Garcia-Doval C, Rostøl JT, Berk C, Schwede F, Bigler L, Hall J, Marraffini LA, Jinek M
Type III CRISPR-Cas systems produce cyclic oligoadenylate second messengers
Jul 19, 2017
Nature
In many prokaryotes, type III CRISPR-Cas systems detect and degrade invasive genetic elements by an RNA-guided, RNA-targeting multisubunit interference complex. The CRISPR-associated protein Csm6 additionally contributes to interference by functioning as a standalone ribonuclease that degrades invader RNA transcripts, but the mechanism linking invader sensing to Csm6 activity is not understood. Here we show that Csm6 proteins are activated through a second messenger generated by the type III interference complex. Upon target RNA binding by the interference complex, its Cas10 subunit converts ATP into a cyclic oligoadenylate product, which allosterically activates Csm6 by binding to its CARF domain. CARF domain mutations that abolish allosteric activation inhibit Csm6 activity in vivo, and mutations in the Cas10 Palm domain phenocopy loss of Csm6. Together, these results point to an unprecedented mechanism for regulation of CRISPR interference that bears striking conceptual similarity to oligoadenylate signalling in mammalian innate immunity.
cGAS surveillance of micronuclei links genome instability to innate immunity
Jul 24, 2017   Nature Add nature.com free-link Cancel
Mackenzie KJ, Carroll P, Martin CA, Murina O, Fluteau A,   . . . . . .   , Nowotny M, Gilbert N, Chandra T, Reijns MAM, Jackson AP
cGAS surveillance of micronuclei links genome instability to innate immunity
Jul 24, 2017
Nature
DNA is strictly compartmentalized within the nucleus to prevent autoimmunity; despite this, cyclic GMP-AMP synthase (cGAS), a cytosolic sensor of double-stranded DNA, is activated in autoinflammatory disorders and by DNA damage. Precisely how cellular DNA gains access to the cytoplasm remains to be determined. Here, we report that cGAS localizes to micronuclei arising from genome instability in a mouse model of monogenic autoinflammation, after exogenous DNA damage and spontaneously in human cancer cells. Such micronuclei occur after mis-segregation of DNA during cell division and consist of chromatin surrounded by its own nuclear membrane. Breakdown of the micronuclear envelope, a process associated with chromothripsis, leads to rapid accumulation of cGAS, providing a mechanism by which self-DNA becomes exposed to the cytosol. cGAS is activated by chromatin, and consistent with a mitotic origin, micronuclei formation and the proinflammatory response following DNA damage are cell-cycle dependent. By combining live-cell laser microdissection with single cell transcriptomics, we establish that interferon-stimulated gene expression is induced in micronucleated cells. We therefore conclude that micronuclei represent an important source of immunostimulatory DNA. As micronuclei formed from lagging chromosomes also activate this pathway, recognition of micronuclei by cGAS may act as a cell-intrinsic immune surveillance mechanism that detects a range of neoplasia-inducing processes.

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