scholarly journals Adenosine Triphosphate Accumulated Following Cerebral Ischemia Induces Neutrophil Extracellular Trap Formation

2020 ◽  
Vol 21 (20) ◽  
pp. 7668
Author(s):  
Seung-Woo Kim ◽  
Dashdulam Davaanyam ◽  
Song-I Seol ◽  
Hye-Kyung Lee ◽  
Hahnbie Lee ◽  
...  
Keyword(s):  
Adenosine Triphosphate ◽  
Neuronal Damage ◽  
Artery Occlusion ◽  
Brain Parenchyma ◽  
Neutrophil Extracellular Trap ◽  
Dependent Manner ◽  
Peptidylarginine Deiminase ◽  
Ischemic Brain ◽  
Cerebral Artery Occlusion ◽  
The Brain

In ischemic stroke, neutrophils infiltrate damaged brain tissue immediately following the ischemic insult and aggravate inflammation via various mechanisms which include neutrophil extracellular traps (NETs) formation. In the present study, we showed that adenosine triphosphate (ATP), a DAMP molecule, accumulates in the brain and induces NETosis in brain parenchyma and in circulating neutrophils (PMNs) isolated from a murine model of stroke induced by middle cerebral artery occlusion (MCAO). Expression of peptidylarginine deiminase-4 (PAD4), which induces citrullination of histones H3 (CitH3) and initiates NETosis, was significantly enhanced in brain parenchyma and blood PMNs following MCAO. ATP or BzATP (a prototypic P2X7R agonist) significantly enhanced the inductions of PAD4 and CitH3 in a P2X7R-dependent manner and intracellular Ca2+ influx, PKCα activation, and NADPH oxidase-dependent reactive oxygen species (ROS) production play critical roles in this ATP-P2X7R-mediated NETosis. In our MCAO animal model, NETosis was markedly suppressed by treatment with apyrase, an enzyme hydrolyzing ATP, but enhanced by co-treatment of BzATP, confirming ATP-P2X7R-mediated NETosis. Since ATP not only induced NETosis but was also extruded after NETosis, our results indicate that ATP accumulated in the ischemic brain induces NETosis, mediating a cross-talk linking NETosis with neuronal damage that might aggravate inflammation and brain damage.

scholarly journals Transient Focal Ischemia Significantly Alters the m 6 A Epitranscriptomic Tagging of RNAs in the Brain

Stroke ◽  
2019 ◽  
Vol 50 (10) ◽  
pp. 2912-2921 ◽  
Author(s):  
Anil K. Chokkalla ◽  
Suresh L. Mehta ◽  
TaeHee Kim ◽  
Bharath Chelluboina ◽  
Jooyong Kim ◽  
...  
Keyword(s):  
Artery Occlusion ◽  
Dot Blot ◽  
Ischemic Brain ◽  
Adverse Conditions ◽  
Functional Implications ◽  
Transient Focal Ischemia ◽  
And Function ◽  
Cerebral Artery Occlusion ◽  
Dot Blot Analysis ◽  
The Brain

Background and Purpose— Adenosine in many types of RNAs can be converted to m 6 A (N 6 -methyladenosine) which is a highly dynamic epitranscriptomic modification that regulates RNA metabolism and function. Of all organs, the brain shows the highest abundance of m 6 A methylation of RNAs. As recent studies showed that m 6 A modification promotes cell survival after adverse conditions, we currently evaluated the effect of stroke on cerebral m 6 A methylation in mRNAs and lncRNAs. Methods— Adult C57BL/6J mice were subjected to transient middle cerebral artery occlusion. In the peri-infarct cortex, m 6 A levels were measured by dot blot analysis, and transcriptome-wide m 6 A changes were profiled using immunoprecipitated methylated RNAs with microarrays (44 122 mRNAs and 12 496 lncRNAs). Gene ontology analysis was conducted to understand the functional implications of m 6 A changes after stroke. Expression of m 6 A writers, readers, and erasers was also estimated in the ischemic brain. Results— Global m 6 A levels increased significantly at 12 hours and 24 hours of reperfusion compared with sham. While 139 transcripts (122 mRNAs and 17 lncRNAs) were hypermethylated, 8 transcripts (5 mRNAs and 3 lncRNAs) were hypomethylated (>5-fold compared with sham) in the ischemic brain at 12 hours reperfusion. Inflammation, apoptosis, and transcriptional regulation are the major biological processes modulated by the poststroke differentially m 6 A methylated mRNAs. The m 6 A writers were unaltered, but the m 6 A eraser (fat mass and obesity-associated protein) decreased significantly after stroke compared with sham. Conclusions— This is the first study to show that stroke alters the cerebral m 6 A epitranscriptome, which might have functional implications in poststroke pathophysiology. Visual Overview— An online visual overview is available for this article.

scholarly journals Iba1+/NG2+ Macrophage-Like Cells Expressing a Variety of Neuroprotective Factors Ameliorate Ischemic Damage of the Brain

2009 ◽  
Vol 30 (3) ◽  
pp. 603-615 ◽  
Author(s):  
Anna Smirkin ◽  
Hiroaki Matsumoto ◽  
Hisaaki Takahashi ◽  
Akihiro Inoue ◽  
Masahiko Tagawa ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Fluorescent Protein ◽  
Artery Occlusion ◽  
Brain Lesions ◽  
Ischemic Lesion ◽  
Ischemic Brain ◽  
Green Fluorescent ◽  
High Level ◽  
Cerebral Artery Occlusion ◽  
The Brain

In a transient 90-min middle cerebral artery occlusion (MCAO) model of rats, a large ischemic lesion is formed where macrophage-like cells massively accumulate, many of which express a macrophage marker, Iba1, and an oligodendrocyte progenitor cell marker, NG2 chondroitin sulfate proteoglycan (NG2); therefore, the cells were termed BINCs (Brain Iba1+/NG2+Cells). A bone marrow transplantation experiment using green-fluorescent protein-transgenic rats showed that BINCs were derived from bone marrow. 5-Fluorouracil (5FU) injection at 2 days post reperfusion (2 dpr) markedly reduced the number of BINCs at 7 dpr, causing enlargement of necrotic volumes and frequent death of the rats. When isolated BINCs were transplanted into 5FU-aggravated ischemic lesion, the volume of the lesion was much reduced. Quantitative real-time RT-PCR showed that BINCs expressed mRNAs encoding bFGF, BMP2, BMP4, BMP7, GDNF, HGF, IGF-1, PDGF-A, and VEGF. In particular, BINCs expressed IGF-1 mRNA at a very high level. Immunohistochemical staining showed that IGF-1-expressing BINCs were found not only in rat but also human ischemic brain lesions. These results suggest that bone marrow-derived BINCs play a beneficial role in ischemic brain lesions, at least in part, through secretion of neuroprotective factors.

scholarly journals Extracellular DJ-1 induces sterile inflammation in the ischemic brain

PLoS Biology ◽  
2021 ◽  
Vol 19 (5) ◽  
pp. e3000939
Author(s):  
Koutarou Nakamura ◽  
Seiichiro Sakai ◽  
Jun Tsuyama ◽  
Akari Nakamura ◽  
Kento Otani ◽  
...  
Keyword(s):  
Extracellular Space ◽  
Neuronal Damage ◽  
Artery Occlusion ◽  
Sterile Inflammation ◽  
Peptide Sequence ◽  
Ischemic Brain ◽  
Molecular Pattern ◽  
Protein Functions ◽  
Toll Like Receptor 2 ◽  
Cerebral Artery Occlusion

Inflammation is implicated in the onset and progression of various diseases, including cerebral pathologies. Here, we report that DJ-1, which plays a role within cells as an antioxidant protein, functions as a damage-associated molecular pattern (DAMP) and triggers inflammation if released from dead cells into the extracellular space. We first found that recombinant DJ-1 protein induces the production of various inflammatory cytokines in bone marrow–derived macrophages (BMMs) and dendritic cells (BMDCs). We further identified a unique peptide sequence in the αG and αH helices of DJ-1 that activates Toll-like receptor 2 (TLR2) and TLR4. In the ischemic brain, DJ-1 is released into the extracellular space from necrotic neurons within 24 h after stroke onset and makes direct contact with TLR2 and TLR4 in infiltrating myeloid cells. Although DJ-1 deficiency in a murine model of middle cerebral artery occlusion did not attenuate neuronal injury, the inflammatory cytokine expression in infiltrating immune cells was significantly decreased. Next, we found that the administration of an antibody to neutralize extracellular DJ-1 suppressed cerebral post-ischemic inflammation and attenuated ischemic neuronal damage. Our results demonstrate a previously unknown function of DJ-1 as a DAMP and suggest that extracellular DJ-1 could be a therapeutic target to prevent inflammation in tissue injuries and neurodegenerative diseases.

scholarly journals TNF-α Pretreatment Induces Protective Effects against Focal Cerebral Ischemia in Mice

1997 ◽  
Vol 17 (5) ◽  
pp. 483-490 ◽  
Author(s):  
Hiroshi Nawashiro ◽  
Kaoru Tasaki ◽  
Christl A. Ruetzler ◽  
John M. Hallenbeck
Keyword(s):  
Infarct Size ◽  
Focal Cerebral Ischemia ◽  
Immunohistochemical Analysis ◽  
Artery Occlusion ◽  
Dependent Manner ◽  
Protective Effects ◽  
Ischemic Brain ◽  
Ischemic Episode ◽  
Factor Α ◽  
Cerebral Artery Occlusion

Cytokines are recognized to play an important role in acute stroke. Tumor necrosis factor- α (TNF) is one of the pro-inflammatory cytokines and is expressed in ischemic brain. We hypothesized that TNF might play a role in the regulation of tolerance to ischemia when administered prior to the ischemic episode. We studied the effects of pretreatment of TNF administered intravenously, intraperitoneally, or intracisternally in mice that were subjected to middle cerebral artery occlusion (MCAO) 48 h later. MCAO was performed in BALB/C mice by direct cauterization of distal MCA, which resulted in pure cortical infarction. A significant reduction in infarct size was noted in mice pretreated by TNF at the dose of 0.5 μg/mouse (p < 0.01) intracisternally. At the doses used in this study, administration of TNF by intravenous or intraperitoneal routes was not effective. Immunohistochemical analysis of brains subjected to 24 h of MCAO revealed a significant decrease in CD11b immunoreactivity after TNF pretreatment compared with control MCAO. Preconditioning with TNF affects infarct size in a time- and dose-dependent manner. TNF induces significant protection against ischemic brain injury and is likely to be involved in the signaling pathways that regulate ischemic tolerance.

scholarly journals Downregulation of Hippocampal Adenosine Kinase after Focal Ischemia as Potential Endogenous Neuroprotective Mechanism

2007 ◽  
Vol 28 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Giuseppe Pignataro ◽  
Samaneh Maysami ◽  
Francesca E Studer ◽  
Andrew Wilz ◽  
Roger P Simon ◽  
...  
Keyword(s):  
Hippocampal Neurons ◽  
Fold Increase ◽  
Cell Loss ◽  
Focal Ischemia ◽  
Artery Occlusion ◽  
Adenosine Kinase ◽  
Protective Mechanism ◽  
Ischemic Brain ◽  
Cerebral Artery Occlusion ◽  
The Brain

The rate of ischemic brain injury varies with the brain region, requiring only hours in striatum but days in hippocampus. Such maturation implies the existence of endogenous neuroprotective mechanisms. Adenosine is an endogenous neuroprotectant regulated by adenosine kinase (ADK). To investigate, whether adenosine might play a role in protecting the hippocampus after focal ischemia, we subjected transgenic mice, which overexpress ADK in hippocampal neurons (Adk-tg mice) to transient middle cerebral artery occlusion (MCAO). Although the hippocampus of wild-type (wt) mice was consistently spared from injury after 60 mins of MCAO, hippocampal injury became evident in Adk-tg mice after only 15 mins of MCAO. To determine, whether downregulation of hippocampal ADK might qualify as candidate mechanism mediating endogenous neuroprotection, we evaluated ADK expression in wt mice after several periods of reperfusion after 15 or 60 mins of MCAO. After 60 mins of MCAO, hippocampal ADK was significantly reduced in both hemispheres after 1, 3, and 24 h of reperfusion. Reduction of ADK-immunoreactivity corresponded to a 2.2-fold increase in hippocampal adenosine at 3 h of reperfusion. Remarkably, a significant reduction of ADK immunoreactivity was also found in the ipsilateral (stroked) hippocampus after 15 mins of MCAO and 3 h of reperfusion. Thus, transient downregulation of hippocampal ADK after stroke might be a protective mechanism during maturation hippocampal cell loss.

scholarly journals Intravenous Transplantation of Mesenchymal Stem Cells Reduces the Number of Infiltrated Ly6C+ Cells but Enhances the Proportions Positive for BDNF, TNF-1α, and IL-1β in the Infarct Cortices of dMCAO Rats

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Yunqian Guan ◽  
Xiaobo Li ◽  
Wenxiu Yu ◽  
Zhaohui Liang ◽  
Min Huang ◽  
...  
Keyword(s):  
Peripheral Circulation ◽  
Artery Occlusion ◽  
Ischemic Brain Injury ◽  
Ischemic Brain ◽  
Allogeneic Mscs ◽  
Infarct Area ◽  
Infiltrating Cells ◽  
Cerebral Artery Occlusion ◽  
The Brain ◽  
Distal Middle Cerebral Artery

The resident microglial and infiltrating cells from peripheral circulation are involved in the pathological processes of ischemia stroke and may be regulated by mesenchymal stem/stromal cell (MSC) transplantation. The present study is aimed at differentiating the neurotrophic and inflammatory roles played by microglial vs. infiltrating circulation-derived cells in the acute phase in rat ischemic brains and explore the influences of intravenously infused allogeneic MSCs. The ischemic brain injury was induced by distal middle cerebral artery occlusion (dMCAO) in SD rats, with or without MSC infusion in the same day following dMCAO. Circulation-derived infiltrating cells in the brain were identified by Ly6C, a majority of which were monocytes/macrophages. Without MSC transplantation, among the infiltrated Ly6C+ cells, some were positive for BDNF, IL-1β, or TNF-α. Following MSC infusion, the overall number of Ly6C+ infiltrated cells was reduced by 50%. In contrast, the proportions of infiltrated Ly6C+ cells coexpressing BDNF, IL-1β, or TNF-α were significantly enhanced. Interestingly, Ly6C+ cells in the infarct area could produce either neurotrophic factor BDNF or inflammatory cytokines (IL-1β or TNF-α), but not both. This suggests that the Ly6C+ cells may constitute heterogeneous populations which react differentially to the microenvironments in the infarct area. The changes in cellular composition in the infarct area may have contributed to the beneficial effect of MSC transplantation.

scholarly journals Electroacupuncture increased cerebral blood flow and reduced ischemic brain injury: dependence on stimulation intensity and frequency

2011 ◽  
Vol 111 (6) ◽  
pp. 1877-1887 ◽  
Author(s):  
Fei Zhou ◽  
Jingchun Guo ◽  
Jieshi Cheng ◽  
Gencheng Wu ◽  
Ying Xia
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Brain Injury ◽  
Ischemic Injury ◽  
Artery Occlusion ◽  
Ischemic Brain Injury ◽  
Ischemic Brain ◽  
Stimulation Parameters ◽  
Cerebral Artery Occlusion ◽  
The Brain

Stroke causes ischemic brain injury and is a leading cause of neurological disability and death. There is, however, no promising therapy to protect the brain from ischemic stress to date. Here we show an exciting finding that optimal electroacupuncture (EA) effectively protects the brain from ischemic injury. The experiments were performed on rats subjected to middle cerebral artery occlusion (MCAO) with continuous monitoring of cerebral blood flow. EA was delivered to acupoints of “Shuigou” (Du 26) and “Baihui” (Du 20) with different intensities and frequencies to optimize the stimulation parameters. The results showed that 1) EA at 1.0–1.2 mA and 5–20 Hz remarkably reduced ischemic infarction, neurological deficit, and death rate; 2) the EA treatment increased the blood flow by >100%, which appeared immediately after the initiation of EA and disappeared after the cessation of EA; 3) the EA treatment promoted the recovery of the blood flow after MCAO; 4) “nonoptimal” parameters of EA (e.g., <0.6 mA or >40 Hz) could not improve the blood flow or reduce ischemic injury; and 5) the same EA treatment with optimal parameters could not increase the blood flow in naive brains. These novel observations suggest that appropriate EA treatment protects the brain from cerebral ischemia by increasing blood flow to the ischemic brain region via a rapid regulation. Our findings have far-reaching impacts on the prevention and treatment of ischemic encephalopathy, and the optimized EA parameters may potentially be a useful clue for the clinical application of EA.

Abstract P766: Ischemic Injury in a Dmcao Model of Stroke Demonstrates Long-Term Immune Cell Diapedesis Into the Brain Parenchyma

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Thomas A Ujas ◽  
Mary K Malone ◽  
Vanessa O Torres ◽  
Sarah Messmer ◽  
Jadwiga Turchan-Cholewo ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Immune Cell ◽  
Artery Occlusion ◽  
Brain Parenchyma ◽  
Brain Hemispheres ◽  
Injured Brain ◽  
Post Hoc ◽  
Cerebral Artery Occlusion ◽  
The Brain

Background: Stroke injury following a middle cerebral artery occlusion (MCAo) induces a rapid migration of leukocytes into the injured brain that lasts for weeks. The current study focuses on whether a focal cortical stroke using the distal MCAo (dMCAo) model induces similar long-term immune cell diapedesis into the brain parenchyma as seen following transient (t)MCAo stroke. Methods: Cells were isolated from spleens and brain hemispheres of adult 1-year old male C57BL/6J (B6; Jackson Labs) mice 30 days after a dMCAo (n=10). Sham animals (n=5) received a craniotomy without the distal MCA ligation. Peripheral migration was assessed in the spleen and brain using flow cytometry (FACSymphony) to identify viable (Ghost dye 780) CD3, CD4, CD8b, CD11b, Ly6C/Ly6G, CD19, CD45, and NK1.1 leukocytes. Populations were analyzed with FlowJo and assessed via repeated measures two-way ANOVA, Sidak post-hoc test (Graphpad Prism). Significance was p<0.05. Results: CD45 + leukocytes were elevated in the ipsilesional (ipsi) hemisphere compared to the contralesional hemisphere (p=0.01) after dMCAo, though a group hemispheric effect (F(1,13)=5.4; p=0.04) suggests long-term inflammation in sham-treated mice. Hemispheric effects also occurred for CD8 + T cells (p=0.046), B cells (p=0.03), monocytes (p=0.01), and macrophages (p=0.06), with elevations in both dMCAo and sham-treated mice in the ipsi vs. contralesional hemispheres. Only monocyte populations were significantly elevated (p=0.03) in dMCAo vs. sham mice. Conclusions: Our study shows that immune cells remain elevated in the injured hemisphere at 30 days after a focal stroke confined to the neocortex, but inflammation occurred in both sham and dMCAo-treated animals. Only monocytes were differentially affected by dMCAo, and infiltrating cell numbers are not as robust as after tMCAo. This demonstrates a long-term injury response from the craniotomy in the dMCAo model that should be considered for long-term studies using this model.

scholarly journals Dendritic Cells Are Present in Ischemic Brain After Permanent Middle Cerebral Artery Occlusion in the Rat

Stroke ◽  
2002 ◽  
Vol 33 (4) ◽  
pp. 1129-1134 ◽  
Author(s):  
Nikolaos Kostulas ◽  
Hu-Lun Li ◽  
Bao-Guo Xiao ◽  
Yu-Min Huang ◽  
Vasilios Kostulas ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Middle Cerebral Artery ◽  
Middle Cerebral Artery Occlusion ◽  
Cerebral Artery ◽  
Artery Occlusion ◽  
Ischemic Brain ◽  
Cerebral Artery Occlusion

scholarly journals Small molecule induces mitochondrial fusion for neuroprotection via targeting CK2 without affecting its conventional kinase activity

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Ke-Wu Zeng ◽  
Jing-Kang Wang ◽  
Li-Chao Wang ◽  
Qiang Guo ◽  
Ting-Ting Liu ◽  
...  
Keyword(s):  
Small Molecule ◽  
Nuclear Translocation ◽  
Fusion Gene ◽  
Artery Occlusion ◽  
Mitochondrial Fusion ◽  
Dependent Manner ◽  
Behavioral Deficits ◽  
Α Subunit ◽  
Cellular Target ◽  
Cerebral Artery Occlusion

AbstractMitochondrial fusion/fission dynamics plays a fundamental role in neuroprotection; however, there is still a severe lack of therapeutic targets for this biological process. Here, we found that the naturally derived small molecule echinacoside (ECH) significantly promotes mitochondrial fusion progression. ECH selectively binds to the previously uncharacterized casein kinase 2 (CK2) α′ subunit (CK2α′) as a direct cellular target, and genetic knockdown of CK2α′ abolishes ECH-mediated mitochondrial fusion. Mechanistically, ECH allosterically regulates CK2α′ conformation to recruit basic transcription factor 3 (BTF3) to form a binary protein complex. Then, the CK2α′/BTF3 complex facilitates β-catenin nuclear translocation to activate TCF/LEF transcription factors and stimulate transcription of the mitochondrial fusion gene Mfn2. Strikingly, in a mouse middle cerebral artery occlusion (MCAO) model, ECH administration was found to significantly improve cerebral injuries and behavioral deficits by enhancing Mfn2 expression in wild-type but not CK2α′+/− mice. Taken together, our findings reveal, for the first time, that CK2 is essential for promoting mitochondrial fusion in a Wnt/β-catenin-dependent manner and suggest that pharmacologically targeting CK2 is a promising therapeutic strategy for ischemic stroke.

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