| 1. |
- Lambertsen, Kate L, et al.
(författare)
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Differences in Origin of Reactive Microglia in Bone Marrow Chimeric Mouse and Rat After Transient Global Ischemia.
- 2011
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Ingår i: Journal of Neuropathology and Experimental Neurology. - 1554-6578. ; 70:6, s. 481-494
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Tidskriftsartikel (refereegranskat)abstract
- Current understanding of microglial involvement in disease is influenced by the observation that recruited bone marrow (BM)-derived cells contribute to reactive microgliosis in BM-chimeric mice. In contrast, a similar phenomenon has not been reported for BM-chimeric rats. We investigated the recruitment and microglial transformation of BM-derived cells in radiation BM-chimeric mice and rats after transientglobal cerebral ischemia, which elicits a characteristic microglialreaction. Both species displayed microglial hyperplasia and rod cell transformation in the hippocampal CA1 region. In mice, a subpopulation of lesion-reactive microglia originated from transformed BM-derived cells. By contrast, no recruitment or microglial transformation of BM-derived cells was observed in BM-chimeric rats. These results suggest that reactive microglia in rats originate from resident microglia, whereas they have a mixed BM-derived and resident origin in mice, depending on the severity of ischemic tissue damage.
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| 2. |
- Bach, Anders, et al.
(författare)
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A high-affinity, dimeric inhibitor of PSD-95 bivalently interacts with PDZ1-2 and protects against ischemic brain damage
- 2012
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 109:9, s. 3317-3322
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Tidskriftsartikel (refereegranskat)abstract
- Inhibition of the ternary protein complex of the synaptic scaffolding protein postsynaptic density protein-95 (PSD-95), neuronal nitric oxide synthase (nNOS), and the N-methyl-D-aspartate (NMDA) receptor is a potential strategy for treating ischemic brain damage, but high-affinity inhibitors are lacking. Here we report the design and synthesis of a novel dimeric inhibitor, Tat-NPEG4(IETDV)(2) (Tat-N-dimer), which binds the tandem PDZ1-2 domain of PSD-95 with an unprecedented high affinity of 4.6 nM, and displays extensive protease-resistance as evaluated in vitro by stability-measurements in human blood plasma. X-ray crystallography, NMR, and small-angle X-ray scattering (SAXS) deduced a true bivalent interaction between dimeric inhibitor and PDZ1-2, and also provided a dynamic model of the conformational changes of PDZ1-2 induced by the dimeric inhibitor. A single intravenous injection of Tat-N-dimer (3 nmol/g) to mice subjected to focal cerebral ischemia reduces infarct volume with 40% and restores motor functions. Thus, Tat-N-dimer is a highly efficacious neuroprotective agent with therapeutic potential in stroke.
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| 3. |
- Clausen, Bettina Hjelm, et al.
(författare)
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Fumarate decreases edema volume and improves functional outcome after experimental stroke
- 2017
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Ingår i: Experimental Neurology. - : Elsevier BV. - 0014-4886. ; 295, s. 144-154
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Tidskriftsartikel (refereegranskat)abstract
- Background Oxidative stress and inflammation exacerbate tissue damage in the brain after ischemic stroke. Dimethyl-fumarate (DMF) and its metabolite monomethyl-fumarate (MMF) are known to stimulate anti-oxidant pathways and modulate inflammatory responses. Considering these dual effects of fumarates, we examined the effect of MMF treatment after ischemic stroke in mice. Methods Permanent middle cerebral artery occlusion (pMCAO) was performed using adult, male C57BL/6 mice. Thirty minutes after pMCAO, 20 mg/kg MMF was administered intravenously. Outcomes were evaluated 6, 24 and 48 h after pMCAO. First, we examined whether a bolus of MMF was capable of changing expression of kelch-like erythroid cell-derived protein with CNC homology-associated protein 1 (Keap1) and nuclear factor erythroid 2-related factor (Nrf)2 in the infarcted brain. Next, we studied the effect of MMF on functional recovery. To explore mechanisms potentially influencing functional changes, we examined infarct volumes, edema formation, the expression of heat shock protein (Hsp)72, hydroxycarboxylic acid receptor 2 (Hcar2), and inducible nitric oxide synthase (iNOS) in the infarcted brain using real-time PCR and Western blotting. Concentrations of a panel of pro- and anti-inflammatory cytokines (IFNγ, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12p70, TNF) were examined in both the infarcted brain tissue and plasma samples 6, 24 and 48 h after pMCAO using multiplex electrochemoluminiscence analysis. Results Administration of MMF increased the protein level of Nrf2 6 h after pMCAO, and improved functional outcome at 24 and 48 h after pMCAO. MMF treatment did not influence infarct size, however reduced edema volume at both 24 and 48 h after pMCAO. MMF treatment resulted in increased Hsp72 expression in the brain 6 h after pMCAO. Hcar2 mRNA levels increased significantly 24 h after pMCAO, but were not different between saline- and MMF-treated mice. MMF treatment also increased the level of the anti-inflammatory cytokine IL-10 in the brain and plasma 6 h after pMCAO, and additionally reduced the level of the pro-inflammatory cytokine IL-12p70 in the brain at 24 and 48 h after pMCAO. Conclusions A single intravenous bolus of MMF improved sensory-motor function after ischemic stroke, reduced edema formation, and increased the levels of the neuroprotective protein Hsp72 in the brain. The early increase in IL-10 and reduction in IL-12p70 in the brain combined with changes in systemic cytokine levels may also contribute to the functional recovery after pMCAO.
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| 4. |
- Inacio, Ana, et al.
(författare)
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Endogenous IFN-β signaling exerts anti-inflammatory actions in experimentally induced focal cerebral ischemia.
- 2015
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Ingår i: Journal of Neuroinflammation. - : Springer Science and Business Media LLC. - 1742-2094. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Interferon (IFN)-β exerts anti-inflammatory effects, coupled to remarkable neurological improvements in multiple sclerosis, a neuroinflammatory condition of the central nervous system. Analogously, it has been hypothesized that IFN-β, by limiting inflammation, decreases neuronal death and promotes functional recovery after stroke. However, the core actions of endogenous IFN-β signaling in stroke are unclear.
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| 5. |
- Madsen, Pernille M, et al.
(författare)
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Genetic ablation of soluble tumor necrosis factor with preservation of membrane tumor necrosis factor is associated with neuroprotection after focal cerebral ischemia.
- 2015
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Ingår i: Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism. - 1559-7016.
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Tidskriftsartikel (refereegranskat)abstract
- Microglia respond to focal cerebral ischemia by increasing their production of the neuromodulatory cytokine tumor necrosis factor, which exists both as membrane-anchored tumor necrosis factor and as cleaved soluble tumor necrosis factor forms. We previously demonstrated that tumor necrosis factor knockout mice display increased lesion volume after focal cerebral ischemia, suggesting that tumor necrosis factor is neuroprotective in experimental stroke. Here, we extend our studies to show that mice with intact membrane-anchored tumor necrosis factor, but no soluble tumor necrosis factor, display reduced infarct volumes at one and five days after stroke. This was associated with improved functional outcome after experimental stroke. No changes were found in the mRNA levels of tumor necrosis factor and tumor necrosis factor-related genes (TNFR1, TNFR2, TACE), pro-inflammatory cytokines (IL-1β, IL-6) or chemokines (CXCL1, CXCL10, CCL2); however, protein expression of TNF, IL-1β, IL-6 and CXCL1 was reduced in membrane-anchored tumor necrosis factor(Δ/Δ) compared to membrane-anchored tumor necrosis factor(wt/wt) mice one day after experimental stroke. This was paralleled by reduced MHCII expression and a reduction in macrophage infiltration in the ipsilateral cortex of membrane-anchored tumor necrosis factor(Δ/Δ) mice. Collectively, these findings indicate that membrane-anchored tumor necrosis factor mediates the protective effects of tumor necrosis factor signaling in experimental stroke, and therapeutic strategies specifically targeting soluble tumor necrosis factor could be beneficial in clinical stroke therapy.
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| 6. |
- Schwengel, Katja, et al.
(författare)
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Angiotensin AT2-receptor stimulation improves survival and neurological outcome after experimental stroke in mice
- 2016
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Ingår i: Journal of Molecular Medicine. - : Springer Science and Business Media LLC. - 0946-2716 .- 1432-1440. ; 94:8, s. 957-966
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the effect of post-stroke, direct AT2-receptor (AT2R) stimulation with the non-peptide AT2R-agonist compound 21 (C21) on infarct size, survival and neurological outcome after middle cerebral artery occlusion (MCAO) in mice and looked for potential underlying mechanisms. C57/BL6J or AT2R-knockout mice (AT2-KO) underwent MCAO for 30 min followed by reperfusion. Starting 45 min after MCAO, mice were treated once daily for 4 days with either vehicle or C21 (0.03 mg/kg ip). Neurological deficits were scored daily. Infarct volumes were measured 96 h post-stroke by MRI. C21 significantly improved survival after MCAO when compared to vehicle-treated mice. C21 treatment had no impact on infarct size, but significantly attenuated neurological deficits. Expression of brain-derived neurotrophic factor (BDNF), tyrosine kinase receptor B (TrkB) (receptor for BDNF) and growth-associated protein 43 (GAP-43) were significantly increased in the peri-infarct cortex of C21-treated mice when compared to vehicle-treated mice. Furthermore, the number of apoptotic neurons was significantly decreased in the peri-infarct cortex in mice treated with C21 compared to controls. There were no effects of C21 on neurological outcome, infarct size and expression of BDNF or GAP-43 in AT2-KO mice. From these data, it can be concluded that AT2R stimulation attenuates early mortality and neurological deficits after experimental stroke through neuroprotective mechanisms in an AT2R-specific way.
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