scholarly journals Normobaric intermittent hypoxic training regulates microglia phenotype and enhances phagocytic activity

2020 ◽  
Vol 245 (8) ◽  
pp. 740-747
Author(s):  
Genell Tantingco ◽  
Myoung-Gwi Ryou
Keyword(s):  
Ischemic Stroke ◽  
Phagocytic Activity ◽  
Glucose Deprivation ◽  
Recovery Process ◽  
Oxygen Glucose Deprivation ◽  
Intermittent Hypoxic Training ◽  
Hypoxic Training ◽  
Pathological Conditions ◽  
Microglia Polarization

The microglia are the resident immune cells in the central nerve system. In the various pathological conditions, prolonged activated microglia could deteriorate brain damage. The regulation of the microglia polarization should be considered in developing an intervention for ischemic stroke patients. Normobaric intermittent hypoxic training protects the brain from intensive ischemic stresses. This study examined the role of intermittent hypoxic training in the regulation of microglia polarization that occurs in the in vitro model of oxygen–glucose deprivation (OGD)–reoxygenation. EOC20 were assigned to the following groups; (1) Normoxia, (2) oxygen–glucose deprivation–reoxygenation, (3) intermittent hypoxic training, (4) oxygen–glucose deprivation–reoxygenation +  intermittent hypoxic training; 24 h after the intermittent hypoxic training, microglia were harvested to perform the following experiments; cell viability (Calcein AM and LDH activity assay), quantification of proteins (Western blot), cytokine (ELISA), and reactive oxygen species (ROS) (H2DCFDA assays), phagocytic activity by using latex beads coated with FITC, and cell phenotype (immunocytochemistry and flow cytometric analysis, and immunoblot CD206 (M2)). One-way ANOVA with Tukey’s post hoc test was used for the statistical analysis. Oxygen–glucose deprivation/reoxygenation decreases cell viability to 50% of normoxia. Intermittent hypoxic training protects the microglia from oxygen–glucose deprivation/reoxygenation stress. Intermittent hypoxic training regulates the polarization of the microglial phenotype toward anti-inflammatory type M2 (vs. oxygen–glucose deprivation and reoxygenation). Intermittent hypoxic training increases phagocytic activity (about 12 folds) vs. normoxia. ROS in the oxygen–glucose deprivation/reoxygenation group is increased, but intermittent hypoxic training lowers the ROS generation by oxygen–glucose deprivation/reoxygenation. The protein content of the toll-like receptor (TLR2) was significantly elevated in the oxygen–glucose deprivation and reoxygenation group, and intermittent hypoxic training lowered to normoxia level. Anti-inflammatory cytokines, such as IL-10 and IL-4, were significantly increased in the intermittent hypoxic training groups. Due to the effect of intermittent hypoxic training on the microglia phenotype, intermittent hypoxic training could be considered as an effective intervention in the treatment or rehabilitation program for the ischemic stroke victims. Impact statement The effects of intermittent hypoxic training or conditioning on many pathological conditions have been widely investigated. One of the pathological conditions dealt with intermittent hypoxic training is ischemic stroke. Well-known mechanisms of intermittent hypoxia-induced protection are related to increased energy metabolism and the enhanced antioxidant effects. In the last decades, the role of microglia in the progress of ischemic stroke-related brain damage has been focused. The dual-edge function of microglia indicates that the microglia-mediated inflammatory response is definitely beneficial in the early stage of ischemic stroke, but long-term activation of microglia is rather detrimental during the recovery process. The effect of IHT on microglia polarization is not investigated. This study focused on whether IHT regulates the polarization of microglia without dampening its classic phagocytic function. This study will provide pivotal information regarding the effects of IHT on the long-term effects on the recovery process from ischemic stroke.

scholarly journals Scoparone protects neuronal cells from oxygen glucose deprivation/reoxygenation injury

RSC Advances ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 2302-2308 ◽  
Author(s):  
Chunfang Wu ◽  
Ting Li ◽  
Baihui Zhu ◽  
Ruiming Zhu ◽  
Youran Zhang ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Causes Of Death ◽  
Neuronal Cells ◽  
Glucose Deprivation ◽  
Oxygen Glucose Deprivation ◽  
The World ◽  
Reoxygenation Injury

Ischemic stroke is one of the leading causes of death and disability in the world.

scholarly journals Upregulation of miR-216a exerts neuroprotective effects against ischemic injury through negatively regulating JAK2/STAT3-involved apoptosis and inflammatory pathways

2019 ◽  
Vol 130 (3) ◽  
pp. 977-988 ◽  
Author(s):  
Yu Shuang Tian ◽  
Di Zhong ◽  
Qing Qing Liu ◽  
Xiu Li Zhao ◽  
Hong Xue Sun ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Inflammatory Mediators ◽  
Neurological Deficit ◽  
Ischemic Injury ◽  
Glucose Deprivation ◽  
Luciferase Assay ◽  
Oxygen Glucose Deprivation ◽  
Tnf Α

OBJECTIVEIschemic stroke remains a significant cause of death and disability in industrialized nations. Janus tyrosine kinase (JAK) and signal transducer and activator of transcription (STAT) of the JAK2/STAT3 pathway play important roles in the downstream signal pathway regulation of ischemic stroke–related inflammatory neuronal damage. Recently, microRNAs (miRNAs) have emerged as major regulators in cerebral ischemic injury; therefore, the authors aimed to investigate the underlying molecular mechanism between miRNAs and ischemic stroke, which may provide potential therapeutic targets for ischemic stroke.METHODSThe JAK2- and JAK3-related miRNA (miR-135, miR-216a, and miR-433) expression levels were detected by real-time quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) and Western blot analysis in both oxygen-glucose deprivation (OGD)–treated primary cultured neuronal cells and mouse brain with middle cerebral artery occlusion (MCAO)–induced ischemic stroke. The miR-135, miR-216a, and miR-433 were determined by bioinformatics analysis that may target JAK2, and miR-216a was further confirmed by 3′ untranslated region (3′UTR) dual-luciferase assay. The study further detected cell apoptosis, the level of lactate dehydrogenase, and inflammatory mediators (inducible nitric oxide synthase [iNOS], matrix metalloproteinase–9 [MMP-9], tumor necrosis factor–α [TNF-α], and interleukin-1β [IL-1β]) after cells were transfected with miR-NC (miRNA negative control) or miR-216a mimics and subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) damage with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, annexin V–FITC/PI, Western blots, and enzyme-linked immunosorbent assay detection. Furthermore, neurological deficit detection and neurological behavior grading were performed to determine the infarction area and neurological deficits.RESULTSJAK2 showed its highest level while miR-216a showed its lowest level at day 1 after ischemic reperfusion. However, miR-135 and miR-433 had no obvious change during the process. The luciferase assay data further confirmed that miR-216a can directly target the 3′UTR of JAK2, and overexpression of miR-216a repressed JAK2 protein levels in OGD/R-treated neuronal cells as well as in the MCAO model ischemic region. In addition, overexpression of miR-216a mitigated cell apoptosis both in vitro and in vivo, which was consistent with the effect of knockdown of JAK2. Furthermore, the study found that miR-216a obviously inhibited the inflammatory mediators after OGD/R, including inflammatory enzymes (iNOS and MMP-9) and cytokines (TNF-α and IL-1β). Upregulating miR-216a levels reduced ischemic infarction and improved neurological deficit.CONCLUSIONSThese findings suggest that upregulation of miR-216a, which targets JAK2, could induce neuroprotection against ischemic injury in vitro and in vivo, which provides a potential therapeutic target for ischemic stroke.

scholarly journals Silencing of Long Noncoding RNA Nespas Aggravates Microglial Cell Death and Neuroinflammation in Ischemic Stroke

Stroke ◽  
2019 ◽  
Vol 50 (7) ◽  
pp. 1850-1858 ◽  
Author(s):  
Yiming Deng ◽  
Duanduan Chen ◽  
Luyao Wang ◽  
Feng Gao ◽  
Bo Jin ◽  
...  
Keyword(s):  
Cell Death ◽  
Ischemic Stroke ◽  
Middle Cerebral Artery ◽  
Long Noncoding Rna ◽  
Noncoding Rna ◽  
Noncoding Rnas ◽  
Glucose Deprivation ◽  
Artery Occlusion ◽  
Oxygen Glucose Deprivation ◽  
Cerebral Artery Occlusion

Background and Purpose— Ischemic stroke is one of the leading causes of morbidity and mortality worldwide and a major cause of long-term disability. Recently, long noncoding RNAs have been revealed, which are tightly associated with several human diseases. However, the functions of long noncoding RNAs in ischemic stroke still remain largely unknown. In the current study, for the first time, we investigated the role of long noncoding RNA Nespas in ischemic stroke. Methods— We used in vivo models of middle cerebral artery occlusion and in vitro models of oxygen-glucose deprivation to illustrate the effect of long noncoding RNA Nespas on ischemic stroke. Results— We found expression of Nespas was significantly increased in ischemic cerebral tissues and oxygen-glucose deprivation–treated BV2 cells in a time-dependent manner. Silencing of Nespas aggravated middle cerebral artery occlusion operation–induced IR injury and cell death. In addition, proinflammatory cytokine production and NF-κB (nuclear factor-κB) signaling activation were inhibited by Nespas overexpression. TAK1 (transforming growth factor-β–activated kinase 1) was found to directly interact with Nespas, and TAK1 activation was significantly suppressed by Nespas. At last, we found Nespas-inhibited TRIM8 (tripartite motif 8)-induced K63-linked polyubiquitination of TAK1. Conclusions— We showed that Nespas played anti-inflammatory and antiapoptotic roles in cultured microglial cells after oxygen-glucose deprivation stimulation and in mice after ischemic stroke by inhibiting TRIM8-related K63-linked polyubiquitination of TAK1.

scholarly journals Expression and Distribution Pattern of Pnn in Ischemic Cerebral Cortex and Cultured Neural Cells Exposed to Oxygen-Glucose Deprivation

2020 ◽  
Vol 10 (10) ◽  
pp. 708
Author(s):  
Shu-Yuan Hsu ◽  
Sujira Mukda ◽  
Steve Leu
Keyword(s):  
Ischemic Stroke ◽  
Mouse Model ◽  
Glucose Deprivation ◽  
Expression Level ◽  
Oxygen Glucose Deprivation ◽  
Neural Cells ◽  
Nuclear Speckle ◽  
Different Types ◽  
Cellular Apoptosis ◽  
Ischemic Stress

Pinin (Pnn), a multifunctional protein, participates in embryonic development as well as in cellular apoptosis, proliferation, and migration through regulating mRNA alternative splicing and gene transcription. Previous studies have shown that Pnn plays important roles in neural system development and the expression level of Pnn in astrocytes is altered by ischemic stress and associated with cellular apoptosis. In the present study, we further utilized primary cultured rat neurons and astrocytes with oxygen-glucose deprivation (OGD) and a mouse model with middle cerebral artery occlusion (MCAO)-induced ischemic stroke to examine the effect of ischemic stress on Pnn expression and distribution in different types of neural cells. Under normoxia, Pnn is mainly localized in the nuclear speckle of primary cultured neurons. The expression level of Pnn was increased after the OGD treatment and then decreased in the reoxygenation period. Moreover, the cytoplasmic expression of Pnn was observed in neurons with OGD and reoxygenation (OGD/R). Unlike that in neurons, the Pnn expression in astrocytes was decreased after OGD treatment and then gradually increased during the reoxygenation period. Of interest, the nuclear–cytoplasmic translocation of Pnn was not observed in astrocytes with OGD/R. In the MCAO mouse model, the neuronal expression of Pnn in the peri-ischemic region was reduced by three days post induction of ischemic stroke. However, the Pnn expression in astrocytes was not altered. Moreover, the nuclear speckle distribution of Pnn in neurons was also diminished following ischemic stroke. In conclusion, the Pnn expression and distribution after OGD and during reoxygenation showed distinct manners in neurons and astrocytes, implying that Pnn may play different roles in different types of neural cells in the stress response to ischemic injury.

scholarly journals Effects of estradiol on ischemic factor-induced astrocyte swelling and AQP4 protein abundance

2011 ◽  
Vol 301 (1) ◽  
pp. C204-C212 ◽  
Author(s):  
Jennifer M. Rutkowsky ◽  
Breanna K. Wallace ◽  
Phyllis M. Wise ◽  
Martha E. O'Donnell
Keyword(s):  
Ischemic Stroke ◽  
Cell Volume ◽  
Cerebral Edema ◽  
Glucose Deprivation ◽  
Aquaporin 4 ◽  
Oxygen Glucose Deprivation ◽  
Protein Abundance ◽  
Astrocyte Swelling ◽  
Aqp4 Protein ◽  
Stimulation Of

In the early hours of ischemic stroke, cerebral edema forms as Na, Cl, and water are secreted across the blood-brain barrier (BBB) and astrocytes swell. We have shown previously that ischemic factors, including hypoxia, aglycemia, and arginine vasopressin (AVP), stimulate BBB Na-K-Cl cotransporter (NKCC) and Na/H exchanger (NHE) activities and that inhibiting NKCC and/or NHE by intravenous bumetanide and/or HOE-642 reduces edema and infarct in a rat model of ischemic stroke. Estradiol also reduces edema and infarct in this model and abolishes ischemic factor stimulation of BBB NKCC and NHE. There is evidence that NKCC and NHE also participate in ischemia-induced swelling of astrocytes. However, little is known about estradiol effects on astrocyte cell volume. In this study, we evaluated the effects of AVP (100 nM), hypoxia (7.5% O2), aglycemia, hypoxia (2%)/aglycemia [oxygen glucose deprivation (OGD)], and estradiol (1–100 nM) on astrocyte cell volume using 3- O-methyl-d-[3H]glucose equilibration methods. We found that AVP, hypoxia, aglycemia, and OGD (30 min to 5 h) each significantly increased astrocyte cell volume, and that estradiol (30–180 min) abolished swelling induced by AVP or hypoxia, but not by aglycemia or OGD. Bumetanide and/or HOE-642 also abolished swelling induced by AVP but not aglycemia. Abundance of aquaporin-4, known to participate in ischemia-induced astrocyte swelling, was significantly reduced following 7-day but not 2- or 3-h estradiol exposures. Our findings suggest that hypoxia, aglycemia, and AVP each contribute to ischemia-induced astrocyte swelling, and that the edema-attenuating effects of estradiol include reduction of hypoxia- and AVP-induced astrocyte swelling and also reduction of aquaporin-4 abundance.

scholarly journals Relaxin Peptide Hormones Are Protective During the Early Stages of Ischemic Stroke in Male Rats

Endocrinology ◽  
2014 ◽  
Vol 156 (2) ◽  
pp. 638-646 ◽  
Author(s):  
Lindsay H. Bergeron ◽  
Jordan M. Willcox ◽  
Faisal J. Alibhai ◽  
Barry J. Connell ◽  
Tarek M. Saleh ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Ischemic Stroke ◽  
Nitric Oxide Synthase ◽  
Infarct Size ◽  
Endothelial Nitric Oxide Synthase ◽  
Glucose Deprivation ◽  
Oxygen Glucose Deprivation ◽  
Protective Mechanisms ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

The pregnancy hormone relaxin protects tissue from ischemic damage. The ability of relaxin-3, a relaxin paralog, to do so has not been explored. The cerebral expression levels of these peptides and their receptors make them logical targets for study in the ischemic brain. We assessed relaxin peptide-mediated protection, relative relaxin family peptide receptor (RXFP) involvement, and protective mechanisms. Sprague-Dawley rats receiving permanent (pMCAO) or transient middle cerebral artery occlusions (tMCAO) were treated with relaxin peptides, and brains were collected for infarct analysis. Activation of the endothelial nitric oxide synthase pathway was evaluated as a potential protective mechanism. Primary cortical rat astrocytes were exposed to oxygen glucose deprivation and treated with relaxin peptides, and viability was examined. Receptor involvement was explored using RXFP3 antagonist or agonist treatment and real-time PCR. Relaxin and relaxin-3 reduced infarct size after pMCAO. Both peptides activated endothelial nitric oxide synthase. Because relaxin-3 has not previously been associated with this pathway and displays promiscuous RXFP binding, we explored the receptor contribution. Expression of rxfp1 was greater than that of rxfp3 in rat brain, although peptide binding at either receptor resulted in similar overall protection after pMCAO. Only RXFP3 activation reduced infarct size after tMCAO. In astrocytes, rxfp3 gene expression was greater than that of rxfp1. Selective activation of RXFP3 maintained astrocyte viability after oxygen glucose deprivation. Relaxin peptides are protective during the early stages of ischemic stroke. Differential responses among treatments and models suggest that RXFP1 and RXFP3 initiate different protective mechanisms. This preliminary work is a pivotal first step in identifying the clinical implications of relaxin peptides in ischemic stroke.

Exacerbation of oxygen–glucose deprivation-induced blood–brain barrier disruption: potential pathogenic role of interleukin-9 in ischemic stroke

2017 ◽  
Vol 131 (13) ◽  
pp. 1499-1513 ◽  
Author(s):  
Sha Tan ◽  
Yilong Shan ◽  
Yuge Wang ◽  
Yinyao Lin ◽  
Siyuan Liao ◽  
...  
Keyword(s):  
T Cells ◽  
Ischemic Stroke ◽  
Blood Brain Barrier ◽  
Mononuclear Cells ◽  
Biological Effects ◽  
Glucose Deprivation ◽  
Brain Barrier ◽  
Oxygen Glucose Deprivation ◽  
Expression Levels ◽  
Blood Brain

Interleukin (IL)-9 exerts a variety of functions in autoimmune diseases. However, its role in ischemic brain injury remains unknown. The present study explored the biological effects of IL-9 in ischemic stroke (IS). We recruited 42 patients newly diagnosed with IS and 22 age- and sex-matched healthy controls. The expression levels of IL-9 and percentages of IL-9-producing T cells, including CD3+CD4+IL-9+ and CD3+CD8+IL-9+ cells, were determined in peripheral blood mononuclear cells (PBMCs) obtained from patients and control individuals. We also investigated the effects of IL-9 on the blood–brain barrier (BBB) following oxygen–glucose deprivation (OGD) and the potential downstream signaling pathways. We found that patients with IS had higher IL-9 expression levels and increased percentages of IL-9-producing T cells in their PBMCs. The percentages of CD3+CD4+IL-9+ and CD3+CD8+IL-9+ T cells were positively correlated with the severity of illness. In in vitro experiments using bEnd.3 cells, exogenously administered IL-9 exacerbated the loss of tight junction proteins (TJPs) in cells subjected to OGD plus reoxygenation (RO). This effect was mediated via activation of IL-9 receptors, which increased the level of endothelial nitric oxide synthase (eNOS), as well as through up-regulated phosphorylation of signal transducer and activator of transcription 1 and 3 and down-regulated phosphorylated protein kinase B/phosphorylated phosphatidylinositol 3-kinase signaling. These results indicate that IL-9 has a destructive effect on the BBB following OGD, at least in part by inducing eNOS production, and raise the possibility of targetting IL-9 for therapeutic intervention in IS.

scholarly journals Role of long noncoding RNA MEG3/miR-378/GRB2 axis in neuronal autophagy and neurological functional impairment in ischemic stroke

2020 ◽  
Vol 295 (41) ◽  
pp. 14125-14139 ◽  
Author(s):  
Hong-Cheng Luo ◽  
Ting-Zhuang Yi ◽  
Fu-Gao Huang ◽  
Ying Wei ◽  
Xiao-Peng Luo ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Functional Impairment ◽  
Molecular Mechanisms ◽  
Glucose Deprivation ◽  
Oxygen Glucose Deprivation ◽  
Neuronal Autophagy

Autophagy has been shown to maintain neural system homeostasis during stroke. However, the molecular mechanisms underlying neuronal autophagy in ischemic stroke remain poorly understood. This study aims to investigate the regulatory mechanisms of the pathway consisting of MEG3 (maternally expressed gene 3), microRNA-378 (miR-378), and GRB2 (growth factor receptor-bound protein 2) in neuronal autophagy and neurological functional impairment in ischemic stroke. A mouse model of the middle cerebral artery occluded–induced ischemic stroke and an in vitro model of oxygen-glucose deprivation–induced neuronal injury were developed. To understand the role of the MEG3/miR-378/GRB2 axis in the neuronal regulation, the expression of proteins associated with autophagy in neurons was measured by Western blotting analysis, and neuron death was evaluated using a lactate dehydrogenase leakage rate test. First, it was found that the GRB2 gene, up-regulated in middle cerebral artery occluded–operated mice and oxygen-glucose deprivation–exposed neurons, was a target gene of miR-378. Next, miR-378 inhibited neuronal loss and neurological functional impairment in mice, as well as neuronal autophagy and neuronal death by silencing of GRB2. Confirmatory in vitro experiments showed that MEG3 could specifically bind to miR-378 and subsequently up-regulate the expression of GRB2, which in turn suppressed the activation of Akt/mTOR pathway. Taken together, these findings suggested that miR-378 might protect against neuronal autophagy and neurological functional impairment and proposed that a MEG3/miR-378/GRB2 regulatory axis contributed to better understanding of the pathophysiology of ischemic stroke.

Abstract 44: Hdac3i Alleviated Ischemic Stroke Injury Through Modulating Aim2 Inflammasome and Microglia Polarization

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Meijuan Zhang ◽  
Mingxu Xia ◽  
Qiuchen Zhao ◽  
Yun Xu
Keyword(s):  
Ischemic Stroke ◽  
Infarct Volume ◽  
Glucose Deprivation ◽  
Vehicle Group ◽  
Triphenyltetrazolium Chloride ◽  
Bv2 Cells ◽  
Severity Scores ◽  
Microglia Polarization

Background: Inflammasome in microglia are critical to elicit inflammatory cascades in ischemic stroke. Histone deacetylases 3 (HDAC3) regulate acetylation states of histone and non-histone proteins and could be a powerful regulator of inflammatory process in stroke. Methods: Primary microglia, BV2 cells subjected to oxygen glucose deprivation (OGD) or LPS stimulation were applied to mimic inflammatory response in vitro . Middle cerebral artery occlusion (MCAO) model were applied to mimic acute stroke in vivo . Ischemic infarct volume and neurological functions were evaluated through 2,3,5-triphenyltetrazolium chloride (TTC) staining and Neurological Severity Scores (NSS) respectively. Expression of HDAC3, AIM2 inflammasome were detected by western blotting, PCR. Immunofluorescence was used to detect M1/M2 polarization. Luciferase activity of absent in melanoma 2 (AIM2) reporter promoter constructs was measured by fluorospectrophotometer. AIM2 knockdown and over-expression leti-virus were constructed to decrease or increase AIM2 expression. HDAC3 inhibitor RGFP966 was used to inhibit acetylation activity of HDAC3. Results: HDAC3 is widely distributed in cerebral cortex, lateral ventricular , hippocampus, cerebellar cortex ; HDAC3 and AIM2 expression were enhanced in LPS stimulated-microglia and MCAO model. A marked stimulatory effect of RGFP966 on H3K9Ac was observed in nuclear extracts form BV2 cells at the dosage of 15 uM. Treatment of RGFP966 increased both IL-4-stimulated expression of Ym-1 and CD206 at 4 h, 10 h, 24 h, 48 h. AIM2, NLRP-1 and NLRP3 significantly increased in MCAO+Vehicle group compared to sham group, but decreased in MCAO+RGFP966 group. RGFP966 inhibited the elevation of circulatory IL-18 and IL-1β induced by stroke. RGFP966 decreased infracted size and alleviated neurological deficit. Conclusions: HDAC3i alleviated ischemic stroke injury through modulating AIM2 inflammasome and microglia polarization. Selective HDAC3 inhibitor-RGFP966 could be a potential medication for combating ischemic brain injury.

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