| 1. |
- Liu, Yawei, et al.
(författare)
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Neuron-mediated generation of regulatory T cells from encephalitogenic T cells suppresses EAE.
- 2006
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Ingår i: Nature Medicine. - : Springer Science and Business Media LLC. - 1546-170X .- 1078-8956. ; 12:5, s. 518-525
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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.
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| 2. |
- Birnir, Bryndis, et al.
(författare)
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The impact of sub-cellular location and intracellular neuronal proteins on properties of GABA(A) receptors
- 2007
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Ingår i: Current Pharmaceutical Design. - : Bentham Science Publishers Ltd.. - 1381-6128 .- 1873-4286. ; 13:31, s. 3169-3177
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Tidskriftsartikel (refereegranskat)abstract
- Most studies of GABA(A) receptor accessory proteins have focused on trafficking, clustering and phosphorylation state of the channel-forming subunits and as a result a number of proteins and mechanisms have been identified that can influence the GABA(A) channel expression and function in the cell plasma membrane. In the light of a growing list of intracellular and transmembrane neuronal proteins shown to affect the fate, function and pharmacology of the GABA(A) receptors in neurons, the concept of what constitutes the native GABA(A) receptor complex may need to be re-examined. It is perhaps more appropriate to consider the associated proteins or some of them to be parts of the receptor channel complex in the capacity of ancillary proteins. Here we highlight some of the effects the intracellular environment has on the GABA-activated channel function and pharmacology. The studies demonstrate the need for co-expression of accessory proteins with the GABA(A) channel-forming subunits in heterologous expression systems in order to obtain the full repertoire of GABA(A) receptors characteristics recorded in the native neuronal environment. Further studies e.g. on gene-modified animal models are needed for most of the accessory proteins to establish their significance in normal physiology and in pathophysiology of neurological and psychiatric diseases. The challenge remains to elucidate the effects that the accessory proteins and processes (e.g. phosphorylation) plus the sub-cellular location have on the "fine-tuning" of the functional and pharmacological properties of the GABA(A) receptor channels.
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| 3. |
- Wallén-Mackenzie, Åsa, et al.
(författare)
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Restricted cortical and amygdaloid removal of vesicular glutamate transporter 2 in preadolescent mice impacts dopaminergic activity and neuronal circuitry of higher brain function.
- 2009
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Ingår i: The Journal of neuroscience : the official journal of the Society for Neuroscience. - 1529-2401 .- 0270-6474. ; 29:7, s. 2238-51
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Tidskriftsartikel (refereegranskat)abstract
- A major challenge in neuroscience is to resolve the connection between gene functionality, neuronal circuits, and behavior. Most, if not all, neuronal circuits of the adult brain contain a glutamatergic component, the nature of which has been difficult to assess because of the vast cellular abundance of glutamate. In this study, we wanted to determine the role of a restricted subpopulation of glutamatergic neurons within the forebrain, the Vglut2-expressing neurons, in neuronal circuitry of higher brain function. Vglut2 expression was selectively deleted in the cortex, hippocampus, and amygdala of preadolescent mice, which resulted in increased locomotor activity, altered social dominance and risk assessment, decreased sensorimotor gating, and impaired long-term spatial memory. Presynaptic VGLUT2-positive terminals were lost in the cortex, striatum, nucleus accumbens, and hippocampus, and a downstream effect on dopamine binding site availability in the striatum was evident. A connection between the induced late-onset, chronic reduction of glutamatergic neurotransmission and dopamine signaling within the circuitry was further substantiated by a partial attenuation of the deficits in sensorimotor gating by the dopamine-stabilizing antipsychotic drug aripiprazole and an increased sensitivity to amphetamine. Somewhat surprisingly, given the restricted expression of Vglut2 in regions responsible for higher brain function, our analyses show that VGLUT2-mediated neurotransmission is required for certain aspects of cognitive, emotional, and social behavior. The present study provides support for the existence of a neurocircuitry that connects changes in VGLUT2-mediated neurotransmission to alterations in the dopaminergic system with schizophrenia-like behavioral deficits as a major outcome.
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| 4. |
- Blomgren, Klas, 1963, et al.
(författare)
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Pathological apoptosis in the developing brain
- 2007
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Ingår i: Apoptosis. - : Springer Science and Business Media LLC. - 1360-8185 .- 1573-675X. ; 12:5, s. 993-1010
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Forskningsöversikt (refereegranskat)abstract
- More than half of the initially-formed neurons are deleted in certain brain regions during normal development. This process, whereby cells are discretely removed without interfering with the further development of remaining cells, is called programmed cell death (PCD). The term apoptosis is used to describe certain morphological manifestations of PCD. Many of the effectors of this developmental cell death program are highly expressed in the developing brain, making it more susceptible to accidental activation of the death machinery, e.g. following hypoxia-ischemia or irradiation. Recent evidence suggests, however, that activation and regulation of cell death mechanisms under pathological conditions do not exactly mirror physiological, developmentally regulated PCD. It may be argued that the conditions after e.g. ischemia are not even compatible with the execution of PCD as we know it. Under pathological conditions cells are exposed to various stressors, including energy failure, oxidative stress and unbalanced ion fluxes. This results in parallel triggering and potential overshooting of several different cell death pathways, which then interact with one another and result in complex patterns of biochemical manifestations and cellular morphological features. These types of cell death are here called "pathological apoptosis," where classical hallmarks of PCD, like pyknosis, nuclear condensation and caspase-3 activation, are combined with non-PCD features of cell death. Here we review our current knowledge of the mechanisms involved, with special focus on the potential for therapeutic intervention tailored to the needs of the developing brain.
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| 5. |
- Zhu, Changlian, 1964, et al.
(författare)
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X chromosome-linked inhibitor of apoptosis protein reduces oxidative stress after cerebral irradiation or hypoxia-ischemia through up-regulation of mitochondrial antioxidants.
- 2007
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Ingår i: The European journal of neuroscience. - : Wiley. - 1460-9568 .- 0953-816X. ; 26:12, s. 3402-10
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate that X chromosome-linked inhibitor of apoptosis protein (XIAP) counteracts oxidative stress in two essentially different disease-related models of brain injury, hypoxia-ischemia and irradiation, as judged by lower expression of nitrotyrosine (5-fold) and 4-hydroxy-2-nonenal (10-fold) in XIAP-overexpressing compared with wild-type mice. XIAP overexpression induced up-regulation of at least three antioxidants residing in mitochondria, superoxide dismutase 2, thioredoxin 2 and lysine oxoglutarate reductase. Cytochrome c release from mitochondria was reduced in XIAP-overexpressing mice. Hence, in addition to blocking caspases, XIAP can regulate reactive oxygen species in the brain, at least partly through up-regulation of mitochondrial antioxidants. XIAP-induced prevention of oxidative stress was not secondary to tissue protection because although XIAP overexpression provides tissue protection after hypoxia-ischemia, it does not prevent tissue loss after irradiation. This is a previously unknown role of XIAP and may provide the basis for development of novel protective strategies for both acute and chronic neurodegenerative diseases, where oxidative stress is an integral component of the injury mechanisms involved.
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| 6. |
- van West, Dirk, et al.
(författare)
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Glucocorticoid receptor gene-based SNP analysis in patients with recurrent major depression
- 2006
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Ingår i: Neuropsychopharmacology. - : Nature Publishing Group. - 0893-133X .- 1740-634X. ; 31:3, s. 620-627
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Tidskriftsartikel (refereegranskat)abstract
- Dysregulation of the hypothalamic-pituitary-adrenal axis, one of the stress-response systems, is one of the key neurobiological features of major depression (MDD). Data supporting the notion that glucocorticoid-mediated feedback inhibition is impaired in MDD come from a multitude of studies demonstrating nonsuppression of cortisol secretion following administration of the synthetic glucocorticoid dexamethasone. We examined whether genetic variations in the glucocorticoid receptor gene (Nuclear Receptor Subfamily 3, Group C, Member 1; NR3C1) could be associated with increased susceptibility for MDD using a whole gene-based association analysis of single nucleotide polymorphisms (SNPs). Four SNPs were identified in NR3C1 and genotyped in two well-diagnosed samples of patients with MDD ascertained in Belgium and northern Sweden, and matched control samples. In total, 314 MDD patients and 354 control individuals were included in the study. In the Belgian sample, we observed significant allele (p=0.02) and genotype (p=0.02) association with an SNP in the promoter region (NR3C1-1); in the Swedish sample, we observed significant allele (p=0.02) and genotype (p=0.02) association with the R23K SNP. The haplotype association studies showed modest evidence for an involvement of the 5' region of the NR3C1 gene in the genetic vulnerability for MDD. This study suggests that polymorphisms in the 5' region of the NR3C1 gene may play a role in the genetic vulnerability for MDD.
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| 7. |
- Gustafson, Deborah, 1966, et al.
(författare)
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Cerebrospinal fluid beta-amyloid 1-42 concentration may predict cognitive decline in older women.
- 2007
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Ingår i: Journal of neurology, neurosurgery, and psychiatry. - : BMJ. - 1468-330X .- 0022-3050. ; 78:5, s. 461-4
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Low levels of cerebrospinal fluid (CSF) beta-amyloid 1-42 (Abeta42) and high total tau (T-tau) are diagnostic for manifest Alzheimer's disease. It is not known, however, whether these biomarkers may be risk indicators for cognitive decline in otherwise healthy older people. METHODS: The longitudinal relationship between CSF markers, Abeta42 and T-tau, measured in 1992, and change in Mini-Mental State Examination (deltaMMSE) score between 1992 and 2002 were investigated in 55 women (aged 70-84 years, mean (SD) MMSE score = 28.3 (1.5)), who were participants in the Prospective Population Study of Women in Gothenburg, Sweden. These women did not have dementia when they experienced lumbar puncture in 1992-3. RESULTS: Over the 8-year follow-up period, deltaMMSE (range = +3 to -21 points) was correlated with Abeta42 (Spearman's r = 0.40, p = 0.002), such that lower levels of Abeta42 were related to greater decline. This was also observed after excluding 4 women who developed dementia between 1992 and 2002 (Spearman's r = 0.34, p = 0.019). A multivariate logistic regression model predicting a decline of > or = 5 points on the MMSE (observed in six women), or a risk of developing dementia over the 8-year follow-up period (observed in four women), including age, education, Abeta42 and T-tau as covariates, showed that Abeta42 was the sole predictor of significant cognitive decline or dementia (OR per 100 pg/ml Abeta42 = 2.24, 95% CI 1.19 to 4.22, p = 0.013). CONCLUSIONS: Low levels of CSF Abeta42 may predict cognitive decline among older women without dementia.
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| 8. |
- Mattsson, Niklas, 1979, et al.
(författare)
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Reduced cerebrospinal fluid BACE1 activity in multiple sclerosis.
- 2009
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Ingår i: Multiple sclerosis (Houndmills, Basingstoke, England). - : SAGE Publications. - 1352-4585 .- 1477-0970. ; 15:4, s. 448-54
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Cell and animal experiments have shown that beta-site APP-cleaving enzyme 1 (BACE1) may be involved in myelination. OBJECTIVE: Here, we assess the association of cerebrospinal fluid (CSF) BACE1 activity with multiple sclerosis (MS). METHODS: BACE1 activity and levels of secreted amyloid precursor protein (APP) and amyloid-beta (Abeta) isoforms were analyzed in CSF from 100 patients with MS and 114 neurologically healthy controls. Patients with systemic lupus erythematosus (SLE), 26 with and 41 without cerebral engagement, were also included to enable comparisons with regards to another autoimmune disease. A subset of patients with MS and controls underwent a second lumbar puncture after 10 years. RESULTS: MS patients had lower CSF BACE1 activity than controls (P = 0.03) and patients with cerebral SLE (P < 0.001). Patients with cerebral SLE had higher BACE1 activity than any other group (P < 0.05 for all comparisons). BACE1 activity correlated with the different amyloid markers in all study groups. BACE1 activity decreased over 10 years in the MS group (P = 0.039) and correlated weakly with clinical disease severity scores in an inverse manner. CONCLUSIONS: These results suggest an involvement of BACE1 in the MS disease process.
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| 9. |
- Sabirsh, A, et al.
(författare)
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Fluorescent leukotriene B-4: potential applications
- 2005
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Ingår i: Journal of Lipid Research. - 1539-7262 .- 0022-2275. ; 46:6, s. 1339-1346
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Tidskriftsartikel (refereegranskat)abstract
- Leukotriene B-4 (LTB4) is a potent lipid mediator of inflammation that acts primarily via a seven-transmembrane-spanning, G-protein-coupled receptor denoted BLT1. Here, we describe the synthesis and characterization of fluorescent analogs of LTB4 that are easy to produce, inexpensive, and without the disadvantages of a radioligand. Fluorescent LTB4 is useful for labeling LTB4 receptors for which no antibodies are available and for performing one-step fluorescence polarization assays conducive to high-throughput screening. We found that orange and green fluorescent LTB4 were full agonists that activated the LTB4 receptor BLT1 with EC50 values of 68 and 40 nM, respectively (4.5 nM for unmodified LTB4). Flow cytometric measurements and confocal imaging showed that fluorescent LTB4 colocalized with BLT1. Fluorescence polarization measurements showed that orange fluorescent LTB4 bound to BLT1 with a K-d of 66 nM and that this binding could be displaced by unlabeled LTB4 and other BLT1-specific ligands. Fluorescent LTB4 analogs were also able to displace tritiated LTB4. Orange fluorescent LTB4 binding to enhanced green fluorescent protein-tagged BLT1 could be observed using fluorescence resonance energy transfer. In addition to being a useful alternative to radiolabeled LTB4, the unique properties of fluorescently labeled LTB4 allow a variety of detection technologies to be used.
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| 10. |
- Zuberovic, Aida, et al.
(författare)
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Proteome profiling of human cerebrospinal fluid: exploring the potential of capillary electrophoresis with surface modified capillaries for analysis of complex biological samples.
- 2008
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Ingår i: European journal of mass spectrometry (Chichester, England). - : SAGE Publications. - 1469-0667 .- 1751-6838. ; 14:4, s. 249-60
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Tidskriftsartikel (refereegranskat)abstract
- A bottom-up proteomic approach, based on capillary electrophoresis (CE) in combination with matrix- assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-ToF/ToF MS), was used to analyze immunoaffinity depleted human cerebrospinal fluid (CSF) and compare it with a non-depleted sample. After enzymatic digestion and desalting, the tryptic peptides were separated by CE using PolyE-323 modified capillaries and fractionated off-line onto MALDI target plates for further analysis by MALDI-MS and MS/MS. The protein profile of the depleted sample was compared with non depleted CSF. Overall, 85 proteins were identified with 95% significance in both samples. The significance scores for proposed biomarkers, such as amyloid-like protein 1 precursor, could be increased up to 12 times after the depletion. Other proteins, often suggested to be related to neurodegenerative diseases, like amyloid beta A4 protein precursor, superoxide dismutase and apolipoprotein E precursor could only be found in the depleted CSF samples. The effect of a derivatization of tryptic peptides with 2- methoxy-4,5-dihydro-1H-imidazole reagent for protein identification with MS was also employed to increase the number of identified proteins and the sequence coverages. The results presented in this study illustrate the benefit of combining a sample pre-fractionation step and a label's ability to enhance the ionization efficiency with the potential of CE using PolyE-323 modified capillaries in the analysis of complex samples. The straight-forward approach that provides speed and simplicity resulting in high-resolution separations and low sample consumption represents an easily applicable separation technique that can serve as a complement to other currently existing analytical approaches needed in modern proteomic analysis of clinically relevant samples.
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