scholarly journals P2Y6 receptor inhibition aggravates ischemic brain injury by reducing microglial phagocytosis

2019 ◽  
Author(s):  
Ruoxue Wen ◽  
Hui Shen ◽  
Shuxian Huang ◽  
Liping Wang ◽  
Zongwei Li ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Myosin Light Chain ◽  
Artery Occlusion ◽  
Walking Test ◽  
Microglial Phagocytosis ◽  
Tnf Α ◽  
Severity Scores ◽  
P2y6 Receptor ◽  
Cerebral Artery Occlusion ◽  
The Brain

Abstract Background Clearance of damaged cells is beneficial for the functional recovery after brain injury. Phagocytosis of tissue and cell debris is an important function of microglia during the development and pathological diseases. However, which specific phagocytic receptor mediates microglial phagocytosis after ischemic stroke is obscure. Methods ICR mice (n=59) underwent 90 minutes transient middle cerebral artery occlusion. P2Y6R, Iba1, GFAP and Tuj-1 double immunostainings were performed to determine P2Y6 receptor location. MRS2578 was injected into mice to inhibit P2Y6 receptor activity. Iba1 and TUNEL staining were performed to examine microglia phagocytosis. Modified neurological severity scores and Grid walking test were used to evaluate the neurological function after ischemic stoke. The expression of IL-1 α, IL-1 β, IL-6, IL-10, TNF-α, TGF-β and MPO was used to examine the inflammation response in the brain. Results The expression of P2Y6 receptor in microglia increased within three days after transient middle cerebral artery occlusion. Inhibition of microglial phagocytosis by the selective inhibitor MRS2578 enlarged the brain atrophy and edema volume after ischemic stroke, subsequently aggravated neurological function using modified neurological severity scores and Grid walking test. MRS2578 treatment had no effect on the expression of IL-1α, IL-1β, IL-6, IL-10, TNF-α, TGF-β and MPO after ischemic stroke, which suggested that it had no effect on the inflammation in the brain. Finally, we found that the expression of myosin light chain kinase decreased after microglial phagocytosis inhibition in ischemic mice, which suggested that myosin light chain kinase was involved in P2Y6 receptor mediated phagocytosis. Conclusion Our results indicated that the P2Y6 receptor mediated microglial phagocytosis played an important role during the acute stage of ischemic stroke, which was a potential target for ischemic stroke treatment.

Abstract 166: Endothelial Overexpression of LOX-1 Increases Stroke Size in vivo

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Alexander Akhmedov ◽  
Remo D Spescha ◽  
Francesco Paneni ◽  
Giovani G Camici ◽  
Thomas F Luescher
Keyword(s):  
Endothelial Cells ◽  
Ischemic Stroke ◽  
Endothelial Dysfunction ◽  
Middle Cerebral Artery ◽  
Middle Cerebral Artery Occlusion ◽  
Cerebral Artery ◽  
Oxidized Ldl ◽  
Artery Occlusion ◽  
Cerebral Artery Occlusion ◽  
The Brain

Background— Stroke is one of the most common causes of death and long term disability worldwide primarily affecting the elderly population. Lectin-like oxidized LDL receptor 1 (LOX-1) is the receptor for oxidized LDL identified in endothelial cells. Binding of OxLDL to LOX-1 induces several cellular events in endothelial cells, such as activation of transcription factor NF-kB, upregulation of MCP-1, and reduction in intracellular NO. Accumulating evidence suggests that LOX-1 is involved in endothelial dysfunction, inflammation, atherogenesis, myocardial infarction, and intimal thickening after balloon catheter injury. Interestingly, a recent study demonstrated that acetylsalicylic acid (aspirin), which could prevent ischemic stroke, inhibited Ox-LDL-mediated LOX-1 expression in human coronary endothelial cells. The expression of LOX-1 was increased at a transient ischemic core site in the rat middle cerebral artery occlusion model. These data suggest that LOX-1 expression induces atherosclerosis in the brain and is the precipitating cause of ischemic stroke. Therefore, the goal of the present study was to investigate the role of endothelial LOX-1 in stroke using experimental mouse model. Methods and Results— 12-week-old male LOX-1TG generated recently in our group and wild-type (WT) mice were applied for a transient middle cerebral artery occlusion (MCAO) model to induce ischemia/reperfusion (I/R) brain injury. LOX-1TG mice developed 24h post-MCAO significantly larger infarcts in the brain compared to WT (81.51±8.84 vs. 46.41±10.13, n=7, p < 0.05) as assessed morphologically using Triphenyltetrazolium chloride (TTC) staining. Moreover, LOX-1TG showed higher neurological deficit in RotaRod (35.57±8.92 vs. 66.14±10.63, n=7, p < 0.05) and Bederson tests (2.22±0.14 vs. 1.25±0.30, n=9-12, p < 0.05) - two experimental physiological tests for neurological function. Conclusions— Thus, our data suggest that LOX-1 plays a critical role in the ischemic stroke when expressed at unphysiological levels. Such LOX-1 -associated phenotype could be due to the endothelial dysfunction. Therefore, LOX-1 may represent novel therapeutic targets for preventing ischemic stroke.

scholarly journals Phosphodiesterase 10A is a critical target for neuroprotection in a mouse model of ischemic stroke

2021 ◽  
Author(s):  
Mustafa Caglar Beker ◽  
Ahmet B. Caglayan ◽  
Serdar Altunay ◽  
Elif Ozbay ◽  
Nilay Ates ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Infarct Volume ◽  
Artery Occlusion ◽  
Cyclic Monophosphate ◽  
Tnf Α ◽  
Liquid Chromatography Tandem Mass ◽  
Inflammatory Processes ◽  
Phosphodiesterase 10A ◽  
Cerebral Artery Occlusion ◽  
Blood Brain Barrier Integrity

Abstract Phosphodiesterase 10A (PDE10A) hydrolyzes adenosine 3′,5′-cyclic monophosphate (cAMP) and guanosine 3′,5′-cyclic monophosphate (cGMP). It is highly expressed in the striatum. Recent evidence implied that PDE10A may be involved in the inflammatory processes following injury, such as ischemic stroke. Its role in ischemic injury was unknown. Herein, we exposed mice to 90 or 30 min middle cerebral artery occlusion, followed by the delivery of the highly selective PDE10A inhibitor TAK-063 (0.3 mg/kg or 3 mg/kg) immediately after reperfusion. Animals were sacrificed after 24 or 72 hours, respectively. Both TAK-063 doses enhanced neurological function, reduced infarct volume, increased neuronal survival, reduced brain edema, and increased blood-brain barrier integrity, alongside cerebral microcirculation improvements. Post-ischemic neuroprotection was associated with increased phosphorylation (i.e., activation) of pro-survival Akt, Erk-1/2 and GSK-3α/β, decreased phosphorylation (i.e., activation) of pro-survival mTOR, increased HIF-1α, MMP-9 and anti-apoptotic Bcl-xL abundance, and reduced pro-apoptotic Bax abundance. Interestingly, PDE10A inhibition reduced inflammatory cytokines/chemokines, including IFN-γ and TNF-α, analyzed by planar surface immunoassay. In addition, liquid chromatography-tandem mass spectrometry revealed 40 proteins were significantly altered by TAK-063. Our study established PDE10A as a target for ischemic stroke therapy.

scholarly journals Image-based stroke rat brain atrophy volume and infarct volume computation

2020 ◽  
Vol 76 (12) ◽  
pp. 10090-10121
Author(s):  
Yung-Kuan Chan ◽  
Chun-Fu Hong ◽  
Meng-Hsiun Tsai ◽  
Ya-Lan Chang ◽  
Ping-Hsuan Sun
Keyword(s):  
Ischemic Stroke ◽  
Rat Brain ◽  
Brain Slice ◽  
Infarct Volume ◽  
Brain Slices ◽  
Artery Occlusion ◽  
Tetrazolium Chloride ◽  
Rat Brain Slice ◽  
Cerebral Artery Occlusion ◽  
The Brain

Abstract Stroke is one of the leading causes of death as well as results in a massive economic burden for society. Stroke is a cerebrovascular disease mainly divided into two types: ischemic stroke and hemorrhagic stroke, which, respectively, refer to the partial blockage and bleeding inside brain blood vessels. Both stroke types lead to nutrient and oxygen deprivation in the brain, which ultimately cause brain damage or death. This study focuses on ischemic stroke in rats with middle cerebral artery occlusion (MCAO) as experimental subjects, and the volumes of infarct and atrophy are calculated based on the brain slice images of rat brains stained with 2,3,5-triphenyl tetrazolium chloride. In this study, a stroke rat brain infarct and atrophy volumes computation system (SRBIAVC system) is developed to segment the infarcts and atrophies from the rat brain slice images. Based on the segmentation results, the infarct and atrophy volumes of a rat brain can be computed. In this study, 168 images of brain slices cut from 28 rat brains with MCAO are used as the test samples. The experimental results show that the segmentation results obtained by the SRBIAVC system are close to those obtained by experts.

scholarly journals The KCa3.1 Blocker TRAM-34 Reduces Infarction and Neurological Deficit in a Rat Model of Ischemia/Reperfusion Stroke

2011 ◽  
Vol 31 (12) ◽  
pp. 2363-2374 ◽  
Author(s):  
Yi-Je Chen ◽  
Girija Raman ◽  
Silke Bodendiek ◽  
Martha E O'Donnell ◽  
Heike Wulff
Keyword(s):  
Ischemic Stroke ◽  
Rat Model ◽  
Neurological Deficit ◽  
Ischemia Reperfusion ◽  
Artery Occlusion ◽  
Beneficial Effects ◽  
Inflammatory Damage ◽  
Male Wistar Rats ◽  
Cerebral Artery Occlusion ◽  
The Brain

Microglia and brain infiltrating macrophages significantly contribute to the secondary inflammatory damage in the wake of ischemic stroke. Here, we investigated whether inhibition of KCa3.1 (IKCa1/KCNN4), a calcium-activated K+ channel that is involved in microglia and macrophage activation and expression of which increases on microglia in the infarcted area, has beneficial effects in a rat model of ischemic stroke. Using an HPLC/MS assay, we first confirmed that our small molecule KCa3.1 blocker TRAM-34 effectively penetrates into the brain and achieves micromolar plasma and brain concentrations after intraperitoneal injection. Then, we subjected male Wistar rats to 90 minutes of middle cerebral artery occlusion (MCAO) and administered either vehicle or TRAM-34 (10 or 40 mg/kg intraperitoneally twice daily) for 7 days starting 12 hours after reperfusion. Both compound doses reduced infarct area by ∼50% as determined by hematoxylin & eosin staining on day 7 and the higher dose also significantly improved neurological deficit. We further observed a significant reduction in ED1+-activated microglia and TUNEL-positive neurons as well as increases in NeuN+ neurons in the infarcted hemisphere. Our findings suggest that KCa3.1 blockade constitutes an attractive approach for the treatment of ischemic stroke because it is still effective when initiated 12 hours after the insult.

scholarly journals Involvement of the Microglial Aryl Hydrocarbon Receptor in Neuroinflammation and Vasogenic Edema after Ischemic Stroke

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 718
Author(s):  
Miki Tanaka ◽  
Masaho Fujikawa ◽  
Ami Oguro ◽  
Kouichi Itoh ◽  
Christoph F. A. Vogel ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Ischemic Stroke ◽  
Aryl Hydrocarbon Receptor ◽  
Vasogenic Edema ◽  
Artery Occlusion ◽  
Aryl Hydrocarbon ◽  
Inflammatory Conditions ◽  
Severity Scores ◽  
Factor Α ◽  
Cerebral Artery Occlusion

Microglia are activated after ischemic stroke and induce neuroinflammation. The expression of the aryl hydrocarbon receptor (AhR) has recently been reported to elicit cytokine expression. We previously reported that microglial activation mediates ischemic edema progression. Thus, the purpose of this study was to examine the role of AhR in inflammation and edema after ischemia using a mouse middle cerebral artery occlusion (MCAO) model. MCAO upregulated AhR expression in microglia during ischemia. MCAO increased the expression of tumor necrosis factor α (TNFα) and then induced edema progression, and worsened the modified neurological severity scores, with these being suppressed by administration of an AhR antagonist, CH223191. In THP-1 macrophages, the NADPH oxidase (NOX) subunit p47phox was significantly increased by AhR ligands, especially under inflammatory conditions. Suppression of NOX activity by apocynin or elimination of superoxide by superoxide dismutase decreased TNFα expression, which was induced by the AhR ligand. AhR ligands also elicited p47phox expression in mouse primary microglia. Thus, p47phox may be important in oxidative stress and subsequent inflammation. In MCAO model mice, P47phox expression was upregulated in microglia by ischemia. Lipid peroxidation induced by MCAO was suppressed by CH223191. Taken together, these findings suggest that AhR in the microglia is involved in neuroinflammation and subsequent edema, after MCAO via p47phox expression upregulation and oxidative stress.

scholarly journals Phosphodiesterase 10A is a critical target for neuroprotection in a mouse model of ischemic stroke

2021 ◽  
Author(s):  
Mustafa C. Beker ◽  
Ahmet B.Caglayan ◽  
Serdar Altunay ◽  
Elif Ozbay ◽  
Nilay Ates ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Infarct Volume ◽  
Artery Occlusion ◽  
Cyclic Monophosphate ◽  
Tnf Α ◽  
Liquid Chromatography Tandem Mass ◽  
Inflammatory Processes ◽  
Phosphodiesterase 10A ◽  
Cerebral Artery Occlusion ◽  
Blood Brain Barrier Integrity

Abstract Phosphodiesterase 10A (PDE10A) hydrolyzes adenosine 3′,5′-cyclic monophosphate (cAMP) and guanosine 3′,5′-cyclic monophosphate (cGMP). It is highly expressed in the striatum. Recent evidence implied that PDE10A may be involved in the inflammatory processes following injury, such as ischemic stroke. Its role in ischemic injury was unknown. Herein, we exposed mice to 90 or 30 min middle cerebral artery occlusion, followed by the delivery of the highly selective PDE10A inhibitor TAK-063 (0.3 mg/kg or 3 mg/kg) immediately after reperfusion. Animals were sacrificed after 24 or 72 hours, respectively. Both TAK-063 doses enhanced neurological function, reduced infarct volume, increased neuronal survival, reduced brain edema, and increased blood-brain barrier integrity, alongside cerebral microcirculation improvements. Post-ischemic neuroprotection was associated with increased phosphorylation (i.e., activation) of pro-survival Akt, Erk-1/2 and GSK-3α/β, decreased phosphorylation (i.e., activation) of pro-survival mTOR, increased HIF-1α, MMP-9 and anti-apoptotic Bcl-xL abundance, and reduced pro-apoptotic Bax abundance. Interestingly, PDE10A inhibition reduced inflammatory cytokines/chemokines, including IFN-γ and TNF-α, analyzed by planar surface immunoassay. In addition, liquid chromatography-tandem mass spectrometry revealed 40 proteins were significantly altered by TAK-063. Our study established PDE10A as a target for ischemic stroke therapy.

scholarly journals Sphingosine 1-phosphate, a Novel TREM2 Ligand, Promotes Phagocytosis and Reduce Ischemic Injury

2020 ◽  
Author(s):  
Xiu-Lan Sun ◽  
Teng-Fei Xue ◽  
Juan Ji ◽  
Ruo-Bing Guo ◽  
Yu-Qin Sun ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Infarct Volume ◽  
Glucose Deprivation ◽  
Artery Occlusion ◽  
Endogenous Ligand ◽  
Microglial Phagocytosis ◽  
Neurological Score ◽  
Cellular Debris ◽  
Sphingosine 1 Phosphate ◽  
Cerebral Artery Occlusion

Abstract Background: Activation of TREM2 protects against brain injury in ischemic stroke via immunoregulation. However, the endogenous ligand of TREM2 remains unknown. Here, we tested the hypothesis that S1P, an immunoregulator, functions as TREM2 ligand to promote microglial phagocytosis.Methods: SD rats, C57BL/6J mice and TREM2-/- mice were subjected to transient middle cerebral artery occlusion, and primary microglia were subjected to oxygen-glucose deprivation. Phagocytosis was investigated via immunofluorescence and two-photon microscope. LC-MS/MS, microscale thermophoresis and surface plasmon resonance were used to confirm the TREM2-S1P interaction.Results: FTY720, an analog of S1P, promoted microglial phagocytosis in ischemic stroke independent of S1PRs expressed on microglia. S1P was confirmed to be a novel endogenous ligand for TREM2 and promote cellular debris clearance. The enhanced cellular debris clearance ameliorated neurological score and infarct volume, relying on TREM2. Moreover, FTY720 was demonstrated to promote hemoglobin clearance in intracerebral hemorrhage and ameliorate hemorrhagic injury.Conlusions: The present work reveals for the first time that S1P acts as a novel endogenous ligand of TREM2 to effectively promote microglial phagocytosis, and provides a new lead compound for developing TREM2 modulator.

Abstract WP322: Do Mural Cells Differentiate Into Microglia-Like Cells After Ischemic Stroke?

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Yao Yao ◽  
Abhijit Nirwane
Keyword(s):  
Ischemic Stroke ◽  
Substantial Reduction ◽  
Transgenic Animals ◽  
Artery Occlusion ◽  
Lineage Tracing ◽  
Future Research ◽  
Mural Cells ◽  
Reporter Mice ◽  
Cerebral Artery Occlusion ◽  
The Brain

Introduction: Controversial results exist on whether mural cells can differentiate into microglia-like cells after ischemic stroke. This discrepancy can be due to different experimental methods (immunostaining versus lineage tracing) and/or distinct transgenic animals (RGS5 GFP versus Tbx18-CreERT mice). Methods: To determinate whether mural cells are able to differentiate into microglia-like cells after ischemic stroke, we permanently labeled mural cells with tdTomato by crossing PDGFRβ-Cre and PDGFRβ-CreERT with Ai14 reporter mice. The resulting Ai14:PDGFRβ-Cre + and Ai14:PDGFRβ-CreERT + mice were subjected to 45 minutes of middle cerebral artery occlusion (MCAO) followed by reperfusion. At various time points after injury, the proliferation, apoptosis, and differentiation of PDGFRβ + cells were examined. Results: In both Ai14:PDGFRβ-Cre + and Ai14:PDGFRβ-CreERT + mice, we observed a substantial reduction of PDGFRβ + cells at day 2 after ischemic stroke and a subsequent repopulation (mainly due to proliferation) of PDGFRβ + cells at day 7 after ischemic stroke. We also showed that PDGFRβ + cells changed their morphology and differentiated into microglia-like cells at day 7 after injury, suggesting that PDGFRβ + cells can indeed differentiate into microglia-like cells after ischemic stroke. In addition, we noted that PDGFRβ also labeled Col1α1 + fibroblasts in the brain. Interestingly, high numbers of PDGFRβ + Col1α1 + cells were found in both Ai14:PDGFRβ-Cre + and Ai14:PDGFRβ-CreERT + mice at day 7 after ischemic injury. Conclusions: These results suggest that PDGFRβ is not an ideal marker for mural cells in pathological conditions that involve fibroblast activation. It remains unclear whether mural cells or fibroblasts differentiate into microglia-like cells after ischemic stroke. Future research should focus on answering this important question.

scholarly journals A Sphingosine 1-Phosphate Gradient Is Linked to the Cerebral Recruitment of T Helper and Regulatory T Helper Cells during Acute Ischemic Stroke

2020 ◽  
Vol 21 (17) ◽  
pp. 6242
Author(s):  
Alexandra Lucaciu ◽  
Hannah Kuhn ◽  
Sandra Trautmann ◽  
Nerea Ferreirós ◽  
Helmuth Steinmetz ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Expression Patterns ◽  
Treg Cells ◽  
Artery Occlusion ◽  
T Helper ◽  
Sphingosine 1 Phosphate ◽  
Cerebral Artery Occlusion ◽  
Kinetics Of ◽  
The Brain

Emerging evidence suggests a complex relationship between sphingosine 1-phosphate (S1P) signaling and stroke. Here, we show the kinetics of S1P in the acute phase of ischemic stroke and highlight accompanying changes in immune cells and S1P receptors (S1PR). Using a C57BL/6 mouse model of middle cerebral artery occlusion (MCAO), we assessed S1P concentrations in the brain, plasma, and spleen. We found a steep S1P gradient from the spleen towards the brain. Results obtained by qPCR suggested that cells expressing the S1PR type 1 (S1P1+) were the predominant population deserting the spleen. Here, we report the cerebral recruitment of T helper (TH) and regulatory T (TREG) cells to the ipsilateral hemisphere, which was associated with differential regulation of cerebral S1PR expression patterns in the brain after MCAO. This study provides insight that the S1P-S1PR axis facilitates splenic T cell egress and is linked to the cerebral recruitment of S1PR+ TH and TREG cells. Further insights by which means the S1P-S1PR-axis orchestrates neuronal positioning may offer new therapeutic perspectives after ischemic stroke.

scholarly journals The Hsp90 Inhibitor 17-DMAG Attenuates Hyperglycemia-Enhanced Hemorrhagic Transformation in Experimental Stroke

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Jiaming Zhang ◽  
Kai Wang ◽  
Jia Qi ◽  
Xiaodong Cao ◽  
Feng Wang
Keyword(s):  
Ischemic Stroke ◽  
Hsp90 Inhibitor ◽  
Hemorrhagic Transformation ◽  
Artery Occlusion ◽  
Vital Role ◽  
Experimental Stroke ◽  
Acute Hyperglycemia ◽  
Inflammatory Molecules ◽  
Cerebral Artery Occlusion ◽  
The Brain

Introduction. Hemorrhagic transformation (HT) is one of the most common complications of ischemic stroke which is exacerbated by hyperglycemia. Oxidative stress, inflammatory response, and matrix metalloproteinases (MMPs) have been evidenced to play a vital role in the pathophysiology of HT. Our previous study has reported that 17-DMAG, an Hsp90 inhibitor, protects the brain against ischemic injury via inhibiting inflammation and reducing MMP-9 after ischemia. However, whether 17-DMAG would attenuate HT in hyperglycemic middle cerebral artery occlusion (MCAO) rats is still unknown. Methods. Acute hyperglycemia was induced by an injection of 50% dextrose. Rats were pretreated with 17-DMAG before MCAO. Infarction volume, hemorrhagic volume neurological scores, expressions of inflammatory molecules and tight junction proteins, and activity of MMP-2 and MMP-9 were assessed 24 h after MCAO. Results. 17-DMAG was found to reduce HT, improve neurological function, and inhibit expressions of inflammatory molecules and the activation of MMPs at 24 h after MCAO. Conclusion. These results implicated that Hsp90 could be a novel therapeutic target in HT following ischemic stroke.

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