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 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 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 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.

scholarly journals Antineuroinflammatory effects of dl-3-n-butylphthalide conferred by stimulation of Foxp3 and Ki-67 in an ischemic stroke model

2020 ◽  
Author(s):  
Xi Liu ◽  
Runzhe Liu ◽  
Dongxu Fu ◽  
Hao Wu ◽  
Xin Zhao ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Artery Occlusion ◽  
Neurological Deficits ◽  
Stroke Model ◽  
Ki 67 ◽  
Ischemic Brain ◽  
Caspase 1 ◽  
And Function ◽  
Cerebral Artery Occlusion ◽  
First Time

Abstract Background Dl-3-n-butylphthalide (NBP) has been widely used for the treatment of ischemic stroke in China. However, its mechanisms of action have not been fully elucidated. Methods We established a permanent middle cerebral artery occlusion (pMCAO) rat model and administered 4 mg/kg/d NBP by tail vein injection for 9 days. Changes in some molecules related to neuroinflammation, neovascularization and nerve regeneration were observed, such as MALDI-TOF MSI to study the distribution of phospholipids in the brain, LA-ICP MSI to observe the changes of Foxp3, Ki-67 and pCREB, immunohistochemistry to investigate NLRP3 and its downstream inflammatory products Caspase-1 and IL-1β. Results These results showed that NBP attenuated ischemic damage in pMCAO rats, accompanied by improving neurological deficits. It was revealed for the first time in an animal stroke model that NBP decreased the levels of PE (18:0), NLRP3, Caspase-1 and IL-1β, while increasing the levels of several phospholipids, such as PA (16:0/18:1), PA (18:0/22:6), PE (16:0/22:6), PE (P-18:0/22:6), PE (18:0/22:6), PS (18:0/22:6), PI (18:0/20:4), Foxp3, Ki-67 and pCREB, in the ischemic brain region. Conclusion These results provide evidence that NBP can reduce neuroinflammation in brain tissue and promote the regeneration of nerves and blood vessels, thus exerting a protective effect on neuromorphology and function.

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

Activation of astroglial CB1R mediates cerebral ischemic tolerance induced by electroacupuncture

2021 ◽  
pp. 0271678X2199439
Author(s):  
Cen Yang ◽  
Jingjing Liu ◽  
Jingyi Wang ◽  
Anqi Yin ◽  
Zhenhua Jiang ◽  
...  
Keyword(s):  
Endocannabinoid System ◽  
Artery Occlusion ◽  
Ischemic Tolerance ◽  
Protective Mechanisms ◽  
Promising Therapeutic Approach ◽  
Subsequent Activation ◽  
Cerebral Ischemic ◽  
Cerebral Artery Occlusion ◽  
The Brain

There are no effective treatments for stroke. The activation of endogenous protective mechanisms is a promising therapeutic approach, which evokes the intrinsic ability of the brain to protect itself. Accumulated evidence strongly suggests that electroacupuncture (EA) pretreatment induces rapid tolerance to cerebral ischemia. With regard to mechanisms underlying ischemic tolerance induced by EA, many molecules and signaling pathways are involved, such as the endocannabinoid system, although the exact mechanisms have not been fully elucidated. In the current study, we employed mutant mice, neuropharmacology, microdialysis, and virus transfection techniques in a middle cerebral artery occlusion (MCAO) model to explore the cell-specific and brain region-specific mechanisms of EA-induced neuroprotection. EA pretreatment resulted in increased ambient endocannabinoid (eCB) levels and subsequent activation of ischemic penumbral astroglial cannabinoid type 1 receptors (CB1R) which led to moderate upregulation of extracellular glutamate that protected neurons from cerebral ischemic injury. These findings provide a novel cellular mechanism of EA and a potential therapeutic target for ischemic stroke.

Cerebral hypoxia-ischemia and middle cerebral artery occlusion induce expression of the cannabinoid CB2 receptor in the brain

2007 ◽  
Vol 412 (2) ◽  
pp. 114-117 ◽  
Author(s):  
John C. Ashton ◽  
Rosanna M.A. Rahman ◽  
Shiva M. Nair ◽  
Brad A. Sutherland ◽  
Michelle Glass ◽  
...  
Keyword(s):  
Middle Cerebral Artery ◽  
Middle Cerebral Artery Occlusion ◽  
Cerebral Artery ◽  
Artery Occlusion ◽  
Cerebral Hypoxia ◽  
Cb2 Receptor ◽  
Hypoxia Ischemia ◽  
Cerebral Artery Occlusion ◽  
The Brain
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