1.
Fritz, Michael, 1981-, et al.
(författare)
Interferon-ɣ mediated signaling in the brain endothelium is critical for inflammation-induced aversion
2018
Ingår i: Brain, behavior, and immunity. - Maryland Heights : Academic Press. - 0889-1591 .- 1090-2139. ; 67, s. 54-58
Tidskriftsartikel (refereegranskat) abstract
Systemic inflammation elicits malaise and a negative affective state. The mechanism underpinning the aversive component of inflammation include cerebral prostaglandin synthesis and modulation of dopaminergic reward circuits, but the messengers that mediate the signaling between the peripheral inflammation and the brain have not been sufficiently characterized. Here we investigated the role of interferon-ɣ (IFN-ɣ) in the aversive response to systemic inflammation induced by a low dose (10μg/kg) of lipopolysaccharide (LPS) in mice. LPS induced IFN-ɣ expression in the blood and deletion of IFN-ɣ or its receptor prevented the development of conditioned place aversion to LPS. LPS induced expression of the chemokine Cxcl10 in the striatum of normal mice, but this induction was absent in mice lacking IFN-ɣ receptors or Myd88 in blood brain barrier endothelial cells. Furthermore, inflammation-induced aversion was blocked in mice lacking Cxcl10 or its receptor Cxcr3. Finally, mice with a selective deletion of the IFN-ɣ receptor in brain endothelial cells did not develop inflammation-induced aversion, demonstrating that the brain endothelium is the critical site of IFN-ɣ action. Collectively, these findings show that circulating IFN-ɣ that binds to receptors on brain endothelial cells and induces Cxcl10, is a central link in the signaling chain eliciting inflammation-induced aversion.
2.
Klawonn, Anna, 1985-
(författare)
Molecular Mechanisms of Reward and Aversion
2017
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
Various molecular pathways in the brain shape our understanding of good and bad, as well as our motivation to seek and avoid such stimuli. This work evolves around how systemic inflammation causes aversion; and why general unpleasant states such as sickness, stress, pain and nausea are encoded by our brain as undesirable; and contrary to these questions, how drugs of abuse can subjugate the motivational neurocircuitry of the brain. A common feature of these various disease states is involvement of the motivational neurocircuitry - from mesolimbic to striatonigral pathways. Having an intact motivational system is what helps us evade negative outcomes and approach natural positive reinforcers, which is essential for our survival. During disease-states the motivational neurocircuitry may be overthrown by the molecular mechanisms that originally were meant to aid us.In study I, to investigate how inflammation is perceived as aversive, we used a behavioral test based on Pavlovian place conditioning with the aversive inflammatory stimulus E. coli lipopolysaccharide (LPS). Using a combination of cell-type specific gene deletions, pharmacology, and chemogenetics, we uncovered that systemic inflammation triggered aversion by MyD88-dependent activation of the brain endothelium followed by COX1-mediated cerebral prostaglandin E2 (PGE2) synthesis. Moreover, we showed that inflammation-induced PGE2 targeted EP1 receptors on striatal dopamine D1 receptor–expressing neurons and that this signaling sequence induced aversion through GABA-mediated inhibition of dopaminergic cells. Finally, inflammation-induced aversion was not an indirect consequence of fever or anorexia but constituted an independent inflammatory symptom triggered by a unique molecular mechanism. Collectively, these findings demonstrate that PGE2-mediated modulation of the dopaminergic circuitry is a key mechanism underlying inflammation-induced aversion.In study II, we investigate the role of peripheral IFN-γ in LPS induced conditioned place aversion by employing a strategy based on global and cell-type specific gene deletions, combined with measures of gene-expression. LPS induced IFN-ɣ expression in the blood, and deletion of IFN-ɣ or its receptor prevented conditioned place aversion (CPA) to LPS. LPS increased the expression of chemokine Cxcl10 in the striatum of normal mice. This induction was absent in mice lacking IFN-ɣ receptors or Myd88 in blood brain barrier endothelial cells. Furthermore, inflammation-induced aversion was blocked in mice lacking Cxcl10 or its receptor Cxcr3. Finally, mice with a selective deletion of the IFN-ɣ receptor in brain endothelial cells did not develop inflammation-induced aversion. Collectively, these findings demonstrate that circulating IFN-ɣ binding to receptors on brain endothelial cells which induces Cxcl10, is a central link in the signaling chain eliciting inflammation-induced aversion.In study III, we explored the role of melanocortin 4 receptors (MC4Rs) in aversive processing using genetically modified mice in CPA to various stimuli. In normal mice, robust aversions were induced by systemic inflammation, nausea, pain and kappa opioid receptor-induced dysphoria. In sharp contrast, mice lacking MC4Rs displayed preference towards most of the aversive stimuli, but were indifferent to pain. The unusual flip from aversion to reward in mice lacking MC4Rs was dopamine-dependent and associated with a change from decreased to increased activity of the dopamine system. The responses to aversive stimuli were normalized when MC4Rs were re-expressed on dopamine D1 receptor-expressing cells or in the striatum of mice otherwise lacking MC4Rs. Furthermore, activation of arcuate nucleus proopiomelanocortin neurons projecting to the ventral striatum increased the activity of striatal neurons in a MC4R-dependent manner and elicited aversion. Our findings demonstrate that melanocortin signaling through striatal MC4Rs is critical for assigning negative motivational valence to harmful stimuli.The neurotransmitter acetylcholine has been implied in reward learning and drug addiction. However, the role of cholinergic receptor subtypes in such processes remains elusive. In study IV we investigated the function of muscarinic M4Rs on dopamine D1R expressing neurons and acetylcholinergic neurons, using transgenic mice in various reward-enforced behaviors and in a “waiting”-impulsivity test. Mice lacking M4-receptors from D1-receptor expressing neurons exhibited an escalated reward seeking phenotype towards cocaine and natural reward, in Pavlovian conditioning and an operant self-administration task, respectively. In addition, the M4-D1RCre mice showed impaired waiting impulsivity in the 5-choice-serial-reaction-time-task. On the contrary, mice without M4Rs in acetylcholinergic neurons were unable to learn positive reinforcement to natural reward and cocaine, in an operant runway paradigm and in Pavlovian conditioning. Immediate early gene expression mirrored the behavioral findings arising from M4R-D1R knockout, as cocaine induced cFos and FosB was significantly increased in the forebrain of M4-D1RCre mice, whereas it remained normal in the M4R-ChatCre mice. Our study illustrates that muscarinic M4Rs on specific neural populations, either cholinergic or D1R-expressing, are pivotal for learning processes related to both natural reward and drugs of abuse, with opposing functionality.
3.
Venkatakrishnan, Vignesh, 1987, et al.
(författare)
Novel inhibitory effect of galectin-3 on the respiratory burst induced by Staphylococcus aureus in human neutrophils
2023
Ingår i: Glycobiology. - : OXFORD UNIV PRESS INC. - 1460-2423 .- 0959-6658. ; 33:6, s. 503-511
Tidskriftsartikel (refereegranskat) abstract
Among the responders to microbial invasion, neutrophils represent the earliest and perhaps the most important immune cells that contribute to host defense with the primary role to kill invading microbes using a plethora of stored anti-microbial molecules. One such process is the production of reactive oxygen species (ROS) by the neutrophil enzyme complex NADPH-oxidase, which can be assembled and active either extracellularly or intracellularly in phagosomes (during phagocytosis) and/or granules (in the absence of phagocytosis). One soluble factor modulating the interplay between immune cells and microbes is galectin-3 (gal-3), a carbohydrate-binding protein that regulates a wide variety of neutrophil functions. Gal-3 has been shown to potentiate neutrophil interaction with bacteria, including Staphylococcus aureus, and is also a potent activator of the neutrophil respiratory burst, inducing large amounts of granule-localized ROS in primed cells. Herein, the role of gal-3 in regulating S. aureus phagocytosis and S. aureus-induced intracellular ROS was analyzed by imaging flow cytometry and luminol-based chemiluminescence, respectively. Although gal-3 did not interfere with S. aureus phagocytosis per se, it potently inhibited phagocytosis-induced intracellular ROS production. Using the gal-3 inhibitor GB0139 (TD139) and carbohydrate recognition domain of gal-3 (gal-3C), we found that the gal-3-induced inhibitory effect on ROS production was dependent on the carbohydrate recognition domain of the lectin. In summary, this is the first report of an inhibitory role of gal-3 in regulating phagocytosis-induced ROS production.
4.
Boij, Roland, 1952-
(författare)
Aspects of inflammation, angiogenesis and coagulation in preeclampsia
2016
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
Preeclampsia is a major challenge to obstetricians, due to its impact on maternal and fetal morbidity and mortality and the lack of preventive and treatment strategies. The overall aim of this thesis is to increase the knowledge of the pathogenesis of preeclampsia including the role of inflammation, angiogenesis and coagulation, both locally at the fetomaternal interface and in the maternal circulation. Uncompensated maternal endothelial inflammatory responses to factors from stressed trophoblasts seem to be a major contributor to the syndrome, together with an imbalance in angiogenesis and an activated coagulation system. An increasing amount of data indicates an involvement of the immune system with defect tolerance to the conceptus as an integral part of the pathogenesis, at least in early-onset preeclampsia (EOP).We showed that a single administration of human preeclampsia serum in pregnant IL-10−/− mice induced the full spectrum of preeclampsia-like symptoms including hypoxic injury in uteroplacental tissues and endotheliosis in maternal kidneys. Importantly, preeclampsia serum, as early as 12 to 14 weeks of gestation, disrupted cross talk between trophoblasts and endothelial cells in an in vitro model of endovascular activity (Tube formation test). These results indicate that preeclamptic sera can be used to better understand the pathophysiology and to predict the disorder. Preeclampsia has been associated with increased inflammation, aberrant angiogenesis and activated coagulation, but their correlation and relative contribution are unknown. We found that markers for all these mechanisms were independently associated with preeclampsia. Cytokines, chemokines, and complement factors seem all to be part of a Th1-associated inflammatory reaction in preeclampsia, more pronounced in EOP than in late-onset preeclampsia (LOP), in line with a more homogeneous pathogenesis in EOP as based on placental pathology. In women with intrauterine growth restriction (IUGR), with an anticipated pathologic placentation, only differences in levels for sFlt-1 and PlGF were found in comparison with mothers without IUGR. Thus, sFlt-1 and PlGF seem to be indicators of placental pathology, while other biomarkers might also reflect maternal endothelial pathology. Chemokines, in contrast to cytokines, may prove to be useful markers in preeclampsia.A deficiency in regulatory T (Treg) cells causing reduced immune regulatory capacity has been proposed in preeclampsia. Utilizing recent advances in flow cytometry phenotyping, we found no major alterations in circulating Treg numbers in preeclamptic women compared with normal pregnant and non-pregnant women. However, preeclampsia was associated with increased fractions of CTLA-4+ and CCR4+ cells within Treg subpopulations, which is in line with a migratory defect of Treg cells, and potentially associated with a reduced number of suppressive Treg cells at the fetomaternal interface. As we found that corticosteroid treatment affected the results, it should be accounted for in studies of EOP. Chemokines are supposed to be part of the immune adaptation in pregnancy. We found a decreased expression of CCL18 (Th2/Tregassociated), in trophoblasts from preeclamptic compared to normal pregnant women, indicating a local regulatory defect in preeclampsia, in line with our finding of a possible migratory defect of circulating Treg cells. Due to increased expression of CCL20 (Th17) and CCL22 (Th2) in first trimester placenta and increased circulating levels of CXCL10 (Th1) and CCL20 (Th17) in third trimester preeclamptic women, we suggest that CCL20 and CCL22 may be important for implantation and early placentation while in third trimester of a preeclamptic pregnancy CXCL10 and CCL20 mainly mirror maternal increased endothelial inflammation and aberrant angiogenesis. In summary, we found that preeclampsia is associated with increased inflammation, aberrant angiogenesis and activated coagulation, caused by placental factors in maternal peripheral circulation, more pronounced in the early-onset form of preeclampsia. It also appears that there is a defective modulation of the immune system in preeclamptic pregnancies. The results provide a better understanding of the pathogenesis of preeclampsia and have given suggestions to predictive markers for preeclampsia in the future.
5.
Chenna Narendra, Sudeep
(författare)
Systemic and local regulation of experimental arthritis by IFN-α, dendritic cells and uridine
2017
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
In this thesis, we have studied the immunological processes of joint inflammation that may be targets for future treatment of patients with arthritis. We focus on the immune-modulating properties of interferon-α (IFN-α) and uridine in experimental arthritis. The nucleoside uridine, which is regarded a safe treatment has anti-inflammatory properties notably by inhibiting tumor necrosis factor (TNF) release. Because the inflamed synovium in rheumatoid arthritis (RA) is characterised by pathogenic TNF-production, uridine could potentially be away to ameliorate arthritis. Systemic administration of uridine had no effect on antigeninduced arthritis (AIA), which is a T-cell dependent model where animals are immunized twice (sensitization) with bovine serum albumin (mBSA), before local triggering of arthritis by intra-articular antigen (mBSA) re-challenge. In contrast, intra-articular administration of uridine clearly down modulated development of AIA in a dose dependent manner and inhibited the expression of synovial adhesion molecules, influx of inflammatory leukocytes and synovial expression of TNF and interleukin 6, but did not affect systemic levels of proinflammatory cytokines or antigen-specific T-cell responses. Local administration of uridine may thus be a viable therapeutic option for treatment of arthritis in the future.Viral double-stranded deoxyribonucleic acid (dsRNA), a common nucleic acid found in most viruses, can be found in the joints of RA patients and local deposition of such viral dsRNA induces arthritis by activating IFN-α. Here we show that arthritis induced by dsRNA can be mediated by IFN-producing dendritic cells in the joint and this may thus explain why viral infections are sometimes associated with arthritis.Earlier, to study the effect of dsRNA and IFN-α in an arthritis model, that like RA, is dependent on adaptive immunity, dsRNA and IFN-α were administered individually during the development of AIA. Both molecules clearly protected against AIA in a type I IFN receptor-dependent manner but were only effective if administered in the sensitization phase of AIA. Here we show that the anti-inflammatory effect of IFN-α is critically dependent on signalling via transforming growth factor β (TGF-β) and the enzymatic activity of indoleamine 2,3 dioxygenase 1 (IDO). The IDO enzyme is produced by plasmacytoid DC and this cell type was critically required both during antigen sensitization and in the arthritis phase of AIA for the protective effect of IFN-α against AIA. In contrast, TGF-β and the enzymatic activity of IDO were only required during sensitization, which indicate that they are involved in initial steps of tolerogenic antigen sensitization. In this scenario, IFN- α first activates the enzymatic activity of IDO in pDC, which converts Tryptophan to Kynurenine, which thereafter activates TGF-β. Common for IDO-expressing pDC, Kyn and TGF-β is their ability to induce development of regulatory T cells (Tregs). We found that Tregs were crucial for IFN-α-mediated protection against AIA, but only in the arthritis phase. In line with this, adoptive transfer of Tregs isolated from IFN-α treated mice to recipient animals in the arthritis phase clearly protected against AIA. The numbers of Tregs were not significantly altered by IFN-α but IFN-α increased the suppressive capacity of Tregs against antigen-induced proliferation. This enhanced suppressive activity of Tregs in the arthritis phase was dependent on the earlier activated enzyme IDO1 during the sensitization phase of AIA. Thus, presence of IFN-α at the time of antigen sensitization activates the enzymatic activity of IDO, which generates Tregs with enhanced suppressive capacity that upon antigen re-challenge prevents inflammation. We have thus identified one example of how immune tolerance can be developed, that may be a future way to combat autoimmunity.
6.
7.
8.
Palkovicova, K., et al.
(författare)
A monoclonal antibody specific for a unique biomarker, virenose, in a lipopolysaccharide of Coxiella burnetii
2009
Ingår i: Clinical Microbiology and Infection. - : Elsevier. - 1198-743X .- 1469-0691. ; 15 Suppl 2, s. 183-4
Tidskriftsartikel (refereegranskat) abstract
Q fever is a zoonotic disease caused by Coxiella burnetii. Easy aerosol dissemination, strong environmental persistence and high infectivity make the bacterium a serious threat for humans and animals. A rapid, sensitive and specific test for the infectious agent is still a challenge in the field. C. burnetii expresses a spectrum of amphophilic macromolecules on its surface. Among them, a lipopolysaccharide (LPS) is of particular biological, immunological and medical significance [1]. Upon serial laboratory passages in yolk sacs of embryonated hen eggs, C.
9.
Bruhn, Sören, et al.
(författare)
A Generally Applicable Translational Strategy Identifies S100A4 as a Candidate Gene in Allergy
2014
Ingår i: Science Translational Medicine. - : American Association for the Advancement of Science (AAAS). - 1946-6234 .- 1946-6242. ; 6:218
Tidskriftsartikel (refereegranskat) abstract
The identification of diagnostic markers and therapeutic candidate genes in common diseases is complicated by the involvement of thousands of genes. We hypothesized that genes co-regulated with a key gene in allergy, IL13, would form a module that could help to identify candidate genes. We identified a T helper 2 (T(H)2) cell module by small interfering RNA-mediated knockdown of 25 putative IL13-regulating transcription factors followed by expression profiling. The module contained candidate genes whose diagnostic potential was supported by clinical studies. Functional studies of human TH2 cells as well as mouse models of allergy showed that deletion of one of the genes, S100A4, resulted in decreased signs of allergy including TH2 cell activation, humoral immunity, and infiltration of effector cells. Specifically, dendritic cells required S100A4 for activating T cells. Treatment with an anti-S100A4 antibody resulted in decreased signs of allergy in the mouse model as well as in allergen-challenged T cells from allergic patients. This strategy, which may be generally applicable to complex diseases, identified and validated an important diagnostic and therapeutic candidate gene in allergy.
10.
Ingelsson, Björn, 1983-, et al.
(författare)
Lymphocytes eject interferogenic mitochondrial DNA webs in response to CpG and non-CpG oligodeoxynucleotides of class C
2018
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - Washington, DC, United States : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 115:3, s. E478-E487
Tidskriftsartikel (refereegranskat) abstract
Circulating mitochondrial DNA (mtDNA) is receiving increasing attention as a danger-associated molecular pattern in conditions such as autoimmunity, cancer, and trauma. We report here that human lymphocytes [B cells, T cells, natural killer (NK) cells], monocytes, and neutrophils derived from healthy blood donors, as well as B cells from chronic lymphocytic leukemia patients, rapidly eject mtDNA as web filament structures upon recognition of CpG and non-CpG oligodeoxynucleotides of class C. The release was quenched by ZnCl2, independent of cell death (apoptosis, necrosis, necroptosis, autophagy), and continued in the presence of TLR9 signaling inhibitors. B-cell mtDNA webs were distinct from neutrophil extracellular traps concerning structure, reactive oxygen species (ROS) dependence, and were devoid of antibacterial proteins. mtDNA webs acted as rapid (within minutes) messengers, priming antiviral type I IFN production. In summary, our findings point at a previously unrecognized role for lymphocytes in antimicrobial defense, utilizing mtDNA webs as signals in synergy with cytokines and natural antibodies, and cast light on the interplay between mitochondria and the immune system.
