1.
Liu, Yawei, et al.
(författare)
Neuron-mediated generation of regulatory T cells from encephalitogenic T cells suppresses EAE.
2006
Ingår i: Nature Medicine. - : Springer Science and Business Media LLC. - 1546-170X .- 1078-8956. ; 12:5, s. 518-525
Tidskriftsartikel (refereegranskat) abstract
Neurons have been neglected as cells with a major immune-regulatory function because they do not express major histocompatibility complex class II. Our data show that neurons are highly immune regulatory, having a crucial role in governing T-cell response and central nervous system (CNS) inflammation. Neurons induce the proliferation of activated CD4+ T cells through B7-CD28 and transforming growth factor (TGF)-beta1–TGF-beta receptor signaling pathways, resulting in amplification of T-cell receptor signaling through phosphorylated ZAP-70, interleukin (IL)-2 and IL-9. The interaction between neurons and T cells results in the conversion of encephalitogenic T cells to CD25+TGF-beta1+CTLA-4+FoxP3+ T regulatory (Treg) cells that suppress encephalitogenic T cells and inhibit experimental autoimmune encephalomyelitis. Suppression is dependent on cytotoxic T lymphocyte antigen (CTLA)-4 but not TGF-beta1. Autocrine action of TGF-beta1, however, is important for the proliferative arrest of Treg cells. Blocking the B7 and TGF-beta pathways prevents the CNS-specific generation of Treg cells. These findings show that generation of neuron-dependent Treg cells in the CNS is instrumental in regulating CNS inflammation.
2.
3.
Mottahedin, Amin
(författare)
Developing brain and systemic inflammation: a "Toll-like" link with consequences
2017
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
The developing brain is vulnerable to external insults, and perinatal brain injury (PBI) is a major cause of life-long neurological syndromes such as cerebral palsy. Currently, no pharmaceutical intervention is available. Hypoxia/ischemia (HI), infections and inflammation are implicated in the pathogenesis of PBI. However, the crosstalk between these etiologies is not fully understood. Toll-like receptors (TLR) 3 and TLR2 are responsible for sensing viral and bacterial infections and initiating the inflammatory response. The aim of this thesis was to investigate the effect of systemic inflammation induced by activation of these TLRs on neonatal HI brain injury. We demonstrate that intraperitoneal administration of TLR3 and TLR2 ligands (PolyI:C and P3C, respectively) prior to HI increases the brain injury in neonatal mice. PolyI:C and P3C induced neuroinflammation and altered microglial phenotype as assessed by RT-qPCR, multiplex cytokine assay or flow cytometry. PolyI:C also upregulated the pro-apoptotic gene, Fasl, expression and reduced activation of pro-survival signaling molecule Akt. On the other hand, P3C suppressed mitochondrial respiration, a major mechanism of cellular energy production. P3C, unlike other TLR agonists, induced marked infiltration of leukocytes to the cerebral spinal fluid and brain of neonatal mice and rats. Confocal microscopy, Cre recombinase-mediated gene targeting and in vitro cell transmigra-tion assay revealed the choroid plexus as a site of leukocyte entry. RNA sequencing of the choroid plexus followed by transcriptome cluster analysis and Ingenuity Pathway Analysis revealed potential mechanisms of leukocyte infiltration, including a specific chemotaxis signature and cytoskeleton-related pathways. Finally, we show that N-acetylcysteine treatment inhibits TLR2-mediated leukocyte trafficking in vivo and in vitro. To conclude, this thesis describe a TLR-mediated link between systemic inflammation and developing brain with detrimental consequences on HI brain injury, suggesting potential novel therapeutic strategies.
4.
Greiff, Lennart, et al.
(författare)
Effects of topical platelet activating factor on the guinea-pig tracheobronchial mucosa in vivo
1997
Ingår i: Acta Physiologica Scandinavica. - 0001-6772. ; 160:4, s. 387-391
Tidskriftsartikel (refereegranskat) abstract
Platelet activating factor (PAF) has been reported to produce a variety of airway effects including epithelial damage and increased airway-lung absorption of hydrophilic tracers. The present study examines effects of PAF on the guinea-pig tracheobronchial mucosa in vivo. Vehicle with and without PAF (4.0 and 8.0 nmol) was superfused onto the tracheobronchial mucosa. The levels of 125I-albumin, previously given intravenously, were determined in tracheobronchial lavage fluids as an index of mucosal exudation of plasma. The mucosa was also examined by scanning electron microscopy. In separate animals, 99mTc-DTPA (a low molecular weight, 492 Da, hydrophilic tracer) was superfused onto the mucosal surface through an oro-tracheal catheter, together with vehicle or PAF (8.0 nmol). A gamma camera determined the disappearance rate of 99mTc-DTPA from the airways as an index of mucosal absorption. PAF produced dose-dependent mucosal exudation of plasma up to 20-fold greater than control (P < 0.001). However, PAF did not damage the epithelium and the absorption ability of the airway mucosa was unaffected. The results, in contrast to previous reports, suggest that PAF may not readily damage the airway mucosa even at large exudative doses of the agent. The present finding support the view that the plasticity of the epithelial junctions allows the creation of valve-like paracellular pathways for unidirectional clearance of extravasated plasma into the airway lumen. We suggest that endogenous PAF may participate in first line respiratory defence reactions by causing lumenal entry of bulk plasma without harming the epithelium.
5.
Bhandage, Amol K., 1988-
(författare)
Glutamate and GABA signalling components in the human brain and in immune cells
2016
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
Glutamate and γ-aminobutyric acid (GABA) are the principal excitatory and inhibitory neurotransmitters in the central nervous system (CNS). They both can activate their ionotropic and metabotropic receptors. Glutamate activates ionotropic glutamate receptors (iGlu - AMPA, kainate and NMDA receptors) and GABA activates GABA-A receptors which are modulated by many types of drugs and substances including alcohol. Using real time quantitative polymerase chain reaction, I have shown that iGlu and/or GABA-A receptor subunits were expressed in the hippocampus dentate gyrus (HDG), orbitofrontal cortex (OFC), dorsolateral prefrontal cortex (DL-PFC), central amygdala (CeA), caudate and putamen of the human brain and their expression was altered by chronic excessive alcohol consumption. It indicates that excitatory and inhibitory neurotransmission may have been altered in the brain of human alcoholics. It is possible that changes in one type of neurotransmitter system may drive changes in another. These brain regions also play a role in brain reward system. Any changes in them may lead to changes in the normal brain functions.Apart from the CNS, glutamate and GABA are also present in the blood and can be synthesised by pancreatic islet cells and immune cells. They may act as immunomodulators of circulating immune cells and can affect immune function through glutamate and GABA receptors. I found that T cells from human, rat and mouse lymph nodes expressed the mRNAs and proteins for specific GABA-A receptor subunits. GABA-evoked transient and tonic currents recorded using the patch clamp technique demonstrate the functional GABA-A channel in T cells. Furthermore, the mRNAs for specific iGlu, GABA-A and GABA-B receptor subunits and chloride cotransporters were detected in peripheral blood mononuclear cells (PBMCs) from men, non-pregnant women, healthy and depressed pregnant women. The results indicate that the expression of iGlu, GABA-A and GABA-B receptors is related to gender, pregnancy and mental health and support the notion that glutamate and GABA receptors may modulate immune function. Intra- and interspecies variability exists in the expression and it is further influenced by physiological conditions.
6.
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.
7.
Persson, Carl, et al.
(författare)
Unbalanced research
2001
Ingår i: Trends in Pharmacological Sciences. - 0165-6147. ; 22:10, s. 538-541
Tidskriftsartikel (refereegranskat)
8.
Rodríguez-Piñeiro, Ana María, et al.
(författare)
The colonic mucus protection depends on the microbiota
2015
Ingår i: Gut microbes. - : Informa UK Limited. - 1949-0976 .- 1949-0984. ; 6:5, s. 326-30
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt) abstract
The intestinal mucus is a pivotal part of our intestinal protection. It provides slow diffusion of protective molecules, trapping of luminal material as bacteria and smooth transport in the small intestine. In colon it restricts bacterial access to the epithelium limiting the responses to the enormous bacterial load present at this location. The development of these systems depends on the microbiota composition as seen in our recent study comparing the mucus phenotype in 2 colonies kept in different husbandries within the same SPF animal facility. One colony had impenetrable colonic mucus while the other colony had more penetrable mucus. The mucus phenotypes were transmitted via the microbiota and clear differences in its composition could be detected. Candidates associated with the different colonies were identified but the observed mucus difference could not be assigned to a specific bacterium.
9.
Andersson, Sören, 1957-, et al.
(författare)
CHIMERIC MOMP ANTIGEN
2015
Patent (populärvet., debatt m.m.)
10.
Moens, Lotte N. J., et al.
(författare)
HaloPlex Targeted Resequencing for Mutation Detection in Clinical Formalin-Fixed, Paraffin-Embedded Tumor Samples
2015
Ingår i: Journal of Molecular Diagnostics. - : Elsevier BV. - 1525-1578 .- 1943-7811. ; 17:6, s. 729-739
Tidskriftsartikel (refereegranskat) abstract
In recent years, the advent of massively parallel next-generation sequencing technologies has enabled substantial advances in the study of human diseases. Combined with targeted DNA enrichment methods, high sequence coverage can be obtained for different genes simultaneously at a reduced cost per sample, creating unique opportunities for clinical cancer diagnostics. However, the formalin-fixed, paraffin-embedded (FFPE) process of tissue samples, routinely used in pathology departments, results in DNA fragmentation and nucleotide modifications that introduce a number of technical challenges for downstream biomotecular analyses. We evaluated the HaloPlex target enrichment system for somatic mutation detection in 80 tissue fractions derived from 20 clinical cancer cases with paired tumor and normal tissue available in both FFPE and fresh-frozen format. Several modifications to the standard method were introduced, including a reduced target fragment Length and two strand capturing. We found that FFPE material can be used for HaloPlex-based target enrichment and next-generation sequencing, even when starting from small amounts of DNA. By specifically capturing both strands for each target fragment, we were able to reduce the number of false-positive errors caused by FFPE-induced artifacts and Lower the detection limit for somatic mutations. We believe that the HaloPlex method presented here will be broadly applicable as a tool for somatic mutation detection in clinical cancer settings.
