| 1. |
- Elander, Nils, 1980-, et al.
(författare)
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Genetic deletion of mPGES-1 accelerates intestinal tumorigenesis in APCMin/+ mice
- 2008
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Ingår i: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 372:1, s. 249-253
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Tidskriftsartikel (refereegranskat)abstract
- The induced synthesis of bioactive prostanoids downstream of cyclooxygenase-2 (COX-2) and prostaglandin H2 (PGH2) exerts a critical event in colorectal carcinogenesis. Here we demonstrate that APCMin/+ mice with genetic deletion of microsomal prostaglandin E synthase-1 (mPGES-1), which catalyses the terminal conversion of PGH2 into PGE2, surprisingly develop more and generally larger intestinal tumors than do mPGES-1 wild type littermates (mean number of tumors/intestine 80 vs. 38, p < 0.0005, mean tumor diameter 1.64 vs. 1.12 mm, p < 0.0005). No deviation regarding the expression of other PGE2 related enzymes (COX-1, COX-2, mPGES-2, cPGES, and 15-PGDH) or receptors (EP1-4) was obvious among the mPGES-1 deficient mice. PGE2 levels were suppressed in tumors of mPGES-1 deficient animals, but the concentrations of other PGH2 derived prostanoids were generally enhanced, being most prominent for TxA2 and PGD2. Thus, we hypothesise that a redirected synthesis towards other lipid mediators might (over)compensate for loss of mPGES-1/PGE2 during intestinal tumorigenesis. Nevertheless, our results question the suitability for mPGES-1 targeting therapy in the treatment or prevention of colorectal cancer. © 2008 Elsevier Inc. All rights reserved.
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| 2. |
- Fischer, Hans, et al.
(författare)
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Mechanism of pathogen-specific TLR4 activation in the mucosa: Fimbriae, recognition receptors and adaptor protein selection.
- 2006
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Ingår i: European Journal of Immunology. - : Wiley. - 1521-4141 .- 0014-2980. ; 36:2, s. 267-277
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Tidskriftsartikel (refereegranskat)abstract
- The mucosal host defence discriminates pathogens from commensals, and prevents infection while allowing the normal flora to persist. Paradoxically, Toll-like receptors (TLR) control the mucosal defence against pathogens, even though the TLR recognise conserved molecules like LPS, which are shared between pathogens and commensals. This study proposes a mechanism of pathogen-specific mucosal TLR4 activation, involving adhesive ligands and their host cell receptors. TLR4 signalling was activated in CD14-negative, LPS-unresponsive epithelial cells by P fimbriated, uropathogenic Escherichia coli but not by a mutant lacking fimbriae. Epithelial TLR4 signalling in vivo involved the glycosphingolipid receptors for P fimbriae and the adaptor proteins Toll/IL-1R (TIR) domain-containing adaptor inducing IFN-beta (TRIF)/TRIF-related adaptor molecule (TRAM), but myeloid differentiation protein 88 (MyD88)/TIR domain-containing adaptor protein were not required for the epithelial response. Substituting the P fimbriae with type 1 fimbriae changed TLR4 signalling from the TRIF to the MyD88 adaptor pathway. In addition, the adaptor proteins and the fimbrial type were found to influence bacterial clearance. Trif(-/-) and Tram(-/-) mice remained infected with P fimbriated E. coli but cleared the type 1 fimbriated strain, while Myd88(-/-) mice became carriers of both the P and the type 1 fimbriated bacteria. Thus, TLR4 maybe engaged specifically by pathogens, when the proper cell surface receptors are engaged by virulence ligands.
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| 3. |
- Flores-Langarica, Adriana, et al.
(författare)
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Intestinal CD103+CD11b+ cDC2 conventional dendritic cells are required for primary CD4+ T and B cell responses to soluble flagellin
- 2018
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Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 9:OCT
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Tidskriftsartikel (refereegranskat)abstract
- Systemic immunization with soluble flagellin (sFliC) from Salmonella Typhimurium induces mucosal responses, offering potential as an adjuvant platform for vaccines. Moreover, this engagement of mucosal immunity is necessary for optimal systemic immunity, demonstrating an interaction between these two semi-autonomous immune systems. Although TLR5 and CD103+CD11b+ cDC2 contribute to this process, the relationship between these is unclear in the early activation of CD4+ T cells and the development of antigen-specific B cell responses. In this work, we use TLR5-deficient mice and CD11c-cre.Irf4fl/fl mice (which have reduced numbers of cDC2, particularly intestinal CD103+CD11b+ cDCs), to address these points by studying the responses concurrently in the spleen and the mesenteric lymph nodes (MLN). We show that CD103+CD11b+ cDC2 respond rapidly and accumulate in the MLN after immunization with sFliC in a TLR5-dependent manner. Furthermore, we identify that whilst CD103+CD11b+ cDC2 are essential for the induction of primary T and B cell responses in the mucosa, they do not play such a central role for the induction of these responses in the spleen. Additionally, we show the involvement of CD103+CD11b+ cDC2 in the induction of Th2-associated responses. CD11c-cre.Irf4fl/fl mice showed a reduced primary FliC-specific Th2-associated IgG1 responses, but enhanced Th1-associated IgG2c responses. These data expand our current understanding of the mucosal immune responses promoted by sFliC and highlights the potential of this adjuvant for vaccine usage by taking advantage of the functionality of mucosal CD103+CD11b+ cDC2.
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| 4. |
- Gratz, Nina, et al.
(författare)
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Group A streptococcus activates type I interferon production and MyD88-dependent signaling without involvement of TLR2, TLR4, and TLR9
- 2008
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 283:29, s. 19879-19887
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Tidskriftsartikel (refereegranskat)abstract
- Bacterial pathogens are recognized by the innate immune system through pattern recognition receptors, such as Toll-like receptors (TLRs). Engagement of TLRs triggers signaling cascades that launch innate immune responses. Activation of MAPKs and NF-kappaB, elements of the major signaling pathways induced by TLRs, depends in most cases on the adaptor molecule MyD88. In addition, Gram-negative or intracellular bacteria elicit MyD88-independent signaling that results in production of type I interferon (IFN). Here we show that in mouse macrophages, the activation of MyD88-dependent signaling by the extracellular Gram-positive human pathogen group A streptococcus (GAS; Streptococcus pyogenes) does not require TLR2, a receptor implicated in sensing of Gram-positive bacteria, or TLR4 and TLR9. Redundant engagement of either of these TLR molecules was excluded by using TLR2/4/9 triple-deficient macrophages. We further demonstrate that infection of macrophages by GAS causes IRF3 (interferon-regulatory factor 3)-dependent, MyD88-independent production of IFN. Surprisingly, IFN is induced also by GAS lacking slo and sagA, the genes encoding cytolysins that were shown to be required for IFN production in response to other Gram-positive bacteria. Our data indicate that (i) GAS is recognized by a MyD88-dependent receptor other than any of those typically used by bacteria, and (ii) GAS as well as GAS mutants lacking cytolysin genes induce type I IFN production by similar mechanisms as bacteria requiring cytoplasmic escape and the function of cytolysins.
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| 5. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 6. |
- Mueller, Christian P., et al.
(författare)
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The Cortical Neuroimmune Regulator TANK Affects Emotional Processing and Enhances Alcohol Drinking : A Translational Study
- 2019
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Ingår i: Cerebral Cortex. - : OXFORD UNIV PRESS INC. - 1047-3211 .- 1460-2199. ; 29:4, s. 1736-1751
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Tidskriftsartikel (refereegranskat)abstract
- Alcohol abuse is a major public health problem worldwide. Understanding the molecular mechanisms that control regular drinking may help to reduce hazards of alcohol consumption. While immunological mechanisms have been related to alcohol drinking, most studies reported changes in immune function that are secondary to alcohol use. In this report, we analyse how the gene "TRAF family member-associated NF-kappa B activator" (TANK) affects alcohol drinking behavior. Based on our recent discovery in a large GWAS dataset that suggested an association of TANK, SNP rs197273, with alcohol drinking, we report that SNP rs197273 in TANK is associated both with gene expression (P = 1.16 x 10(-19)) and regional methylation (P = 5.90 x 10(-25)). A tank knock out mouse model suggests a role of TANK in alcohol drinking, anxiety-related behavior, as well as alcohol exposure induced activation of insular cortex NF-kappa B. Functional and structural neuroimaging studies among up to 1896 adolescents reveal that TANK is involved in the control of brain activity in areas of aversive interoceptive processing, including the insular cortex, but not in areas related to reinforcement, reward processing or impulsiveness. Our findings suggest that the cortical neuroimmune regulator TANK is associated with enhanced aversive emotional processing that better protects from the establishment of alcohol drinking behavior.
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| 7. |
- Nyström, Sanna, et al.
(författare)
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DNA-Encoded Flagellin Activates Toll-Like Receptor 5 (TLR5), Nod-like Receptor Family CARD Domain-Containing Protein 4 (NRLC4), and Acts as an Epidermal, Systemic, and Mucosal-Adjuvant
- 2013
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Ingår i: Vaccines. - Basel, Switzerland : MDPI AG. - 2076-393X. ; 1:4, s. 415-443
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Tidskriftsartikel (refereegranskat)abstract
- Eliciting effective immune responses using non-living/replicating DNA vaccines is a significant challenge. We have previously shown that ballistic dermal plasmid DNA-encoded flagellin (FliC) promotes humoral as well as cellular immunity to co-delivered antigens. Here, we observe that a plasmid encoding secreted FliC (pFliC(-gly)) produces flagellin capable of activating two innate immune receptors known to detect flagellin; Toll-like Receptor 5 (TLR5) and Nod-like Receptor family CARD domain-containing protein 4 (NRLC4). To test the ability of pFliC(-gly) to act as an adjuvant we immunized mice with plasmid encoding secreted FliC (pFliC(-gly)) and plasmid encoding a model antigen (ovalbumin) by three different immunization routes representative of dermal, systemic, and mucosal tissues. By all three routes we observed increases in antigen-specific antibodies in serum as well as MHC Class I-dependent cellular immune responses when pFliC(-gly) adjuvant was added. Additionally, we were able to induce mucosal antibody responses and Class II-dependent cellular immune responses after mucosal vaccination with pFliC(-gly). Humoral immune responses elicited by heterologus prime-boost immunization with a plasmid encoding HIV-1 from gp160 followed by protein boosting could be enhanced by use of pFliC(-gly). We also observed enhancement of cross-clade reactive IgA as well as a broadening of B cell epitope reactivity. These observations indicate that plasmid-encoded secreted flagellin can activate multiple innate immune responses and function as an adjuvant to non-living/replicating DNA immunizations. Moreover, the capacity to elicit mucosal immune responses, in addition to dermal and systemic properties, demonstrates the potential of flagellin to be used with vaccines designed to be delivered by various routes.
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| 8. |
- Richter, Cornelia, et al.
(författare)
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Ncf1 Provides a Reactive Oxygen Species-Independent Negative Feedback Regulation of TLR9-Induced IL-12p70 in Murine Dendritic Cells
- 2009
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 1550-6606 .- 0022-1767. ; 182:7, s. 4183-4191
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Tidskriftsartikel (refereegranskat)abstract
- Permanent exposure to pathogens requires decisions toward tolerance or immunity as a prime task of dendritic cells. The molecular mechanisms preventing uncontrolled immune responses are not completely clear. We investigated the regulatory function of Ncf1, an organizing protein of NADPH oxidase, in the signaling cascade of Toll-like receptors. TLR9-stimulated spleen cells from both Ncf1-deficient and B10.Q mice with a point mutation in exon 8 of Ncf1 exhibited increased IL-12p70 secretion compared with controls. This finding was restricted to stimulatory CpG2216 and not induced by CpG2088. Because only CpG/TLR9-induced IL-12p70 was regulated by Ncf1, we used TRIF-/- and MyD88(-/-) cells to show that TLR9/MyD88 was primarily affected. Interestingly, additional experiments revealed that spleen cells from NOX2/gp91(phox)-deficient mice and the blocking of electron transfer by diphenylene iodonium had no influence on CpG-induced IL-12p70, confirming an NADPH oxidase-independent function of Ncf1. Finally, proving the in vivo relevance CpG adjuvant-guided OVA immunization resulted in a strong augmentation of IL-12p70-dependent Th1 IFN-gamma response only in Ncf1-deficient mice. These data suggest for the first time an important role for Ncf1 in, the fine tuning of the TLR9/MyD88 pathway in vitro and in vivo that is independent of its role as an activator of NOX2. The Journal of Immunology, 2009,182: 4183-4191.
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| 9. |
- Schumann, Gunter, et al.
(författare)
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KLB is associated with alcohol drinking, and its gene product beta-Klotho is necessary for FGF21 regulation of alcohol preference
- 2016
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 113:50, s. 14372-14377
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Tidskriftsartikel (refereegranskat)abstract
- Excessive alcohol consumption is a major public health problem worldwide. Although drinking habits are known to be inherited, few genes have been identified that are robustly linked to alcohol drinking. We conducted a genome-wide association metaanalysis and replication study among >105,000 individuals of European ancestry and identified beta-Klotho (KLB) as a locus associated with alcohol consumption (rs11940694; P = 9.2 x 10(-12)). beta-Klotho is an obligate coreceptor for the hormone FGF21, which is secreted from the liver and implicated in macronutrient preference in humans. We show that brain-specific beta-Klotho KO mice have an increased alcohol preference and that FGF21 inhibits alcohol drinking by acting on the brain. These data suggest that a liver-brain endocrine axis may play an important role in the regulation of alcohol drinking behavior and provide a unique pharmacologic target for reducing alcohol consumption.
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