Abstract T P80: Inhibition of Ezh2 Leads to Decreased M1 and Enhanced M2 Microglia Phenotypes

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Edward Koellhoffer ◽  
Jeremy Grenier ◽  
Rodney Ritzel ◽  
Louise McCullough
Keyword(s):  
Ischemic Stroke ◽  
Pcr Analysis ◽  
M2 Polarization ◽  
M2 Microglia ◽  
M1 Polarization ◽  
Glial Cultures ◽  
M2 Response ◽  
M1 Phenotype ◽  
Cayman Chemical ◽  
M2 Phenotype

Background: Ischemic stroke results in the activation of microglia, which may polarize toward a pro-inflammatory (M1) phenotype or an anti-inflammatory, neuroprotective (M2) phenotype. Thus, simultaneously suppressing the M1 response and promoting the M2 response could be beneficial in the treatment of stroke. Recently, the epigenetic modulator Jmjd3 has been shown to be essential for M2 polarization. However, Jmjd3 is antagonized by Ezh2 which is associated with M1 polarization. Thus, we hypothesized that inhibition of Ezh2 tilts the balance between Jmjd3 and Ezh2, thereby enhancing polarization toward an M2 phenotype and improved outcome in ischemic stroke. Methods: Mixed glial cultures were isolated from P0.5-P2 C57BL/6J mice and cultured for 14 days before microglial isolation. Microglia were rested for 24 hours before treatment every other day with 6uM GSK343 (Cayman Chemical) or DMSO vehicle control. After 7 days, microglia were stimulated with LPS or IL-4 and RNA was isolated at 4hr and 24hr post-stimulation for qRT-PCR analysis. Results: LPS-induced IL6 and IL1B expression was significantly abrogated by 71% and 53%, respectively (p<0.05), at 24hr when Ezh2 was inhibited. Additionally, Ezh2 inhibition both increased baseline expression of M2-associated genes ARG1, CD206, and IRF4 by 196%, 257%, and 395%, respectively (p<0.05), and rescued their expression in the presence of LPS at 24hr (p<0.05) in which they were otherwise significantly down-regulated. Conclusion: Pharmacological inhibition of Ezh2 limits microglial M1 polarization and enhances M2 polarization.

scholarly journals The Polarization States of Microglia in TBI: A New Paradigm for Pharmacological Intervention

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Hangzhe Xu ◽  
Zhijiang Wang ◽  
Jianru Li ◽  
Haijian Wu ◽  
Yucong Peng ◽  
...  
Keyword(s):  
Brain Injury ◽  
Current Knowledge ◽  
Microglial Cells ◽  
Pharmacological Intervention ◽  
Secondary Brain Injury ◽  
Neuroprotective Effects ◽  
M2 Polarization ◽  
M1 Phenotype ◽  
Polarization States ◽  
M2 Phenotype

Traumatic brain injury (TBI) is a serious medical and social problem worldwide. Because of the complex pathophysiological mechanisms of TBI, effective pharmacotherapy is still lacking. The microglial cells are resident tissue macrophages located in the brain and have two major polarization states, M1 phenotype and M2 phenotype, when activated. The M1 phenotype is related to the release of proinflammatory cytokines and secondary brain injury, while the M2 phenotype has been proved to be responsible for the release of anti-inflammation cytokines and for central nervous system (CNS) repair. In animal models, pharmacological strategies inhibiting the M1 phenotype and promoting the M2 phenotype of microglial cells could alleviate cerebral damage and improve neurological function recovery after TBI. In this review, we aimed to summarize the current knowledge about the pathological significance of microglial M1/M2 polarization in the pathophysiology of TBI. In addition, we reviewed several drugs that have provided neuroprotective effects against brain injury following TBI by altering the polarization states of the microglia. We emphasized that future investigation of the regulation mechanisms of microglial M1/M2 polarization in TBI is anticipated, which could contribute to the development of new targets of pharmacological intervention in TBI.

Abstract P759: Microglial EZH2 Inhibition Leads to Neuroprotection After Stroke in Aged Mice

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Fan Bu ◽  
Jia-wei Min ◽  
Yan Xu ◽  
Qi Li ◽  
Edward C Koellhoffer ◽  
...  
Keyword(s):  
Infarct Volume ◽  
Brain Infarct ◽  
M2 Polarization ◽  
M1 Polarization ◽  
Microglia Polarization ◽  
M1 Phenotype ◽  
Genetic Deletion ◽  
Adhesive Removal ◽  
Specific Deletion

Introduction: Ischemic stroke results in activation of microglia, which may polarize towards a pro-inflammatory (M1) phenotype and/or an anti-inflammatory (M2) phenotype. Enhancer of zeste homolog (EZH) 2 is a histone-lysine N-methyltransferase enzyme. Accumulating evidence has suggested EZH2 is key modulator of microglia polarization by epigenetically regulating gene expression. We here investigated whether microglial-specific deletion of EZH2 leads to a beneficial protective effect in stroke in vivo . We further tested the therapeutical potential of an EZH2 inhibitor after stroke. Methods: Aged male mice were subjected to 60-minutes middle cerebral artery stroke. Tamoxifen administration was started 30 days prior to stroke to induce genetic deletion of microglial EZH2 in CX3CR1-creER/EZH2-floxed mice. EZH2 floxed mice were used as controls. EZH2 inhibitor GSK343 was I.P. injected (once a day for two consecutive days), starting three hours after stroke onset. Mice were sacrificed for immunohistochemistry and crystal violet staining (brain infarct assay) after behavior tests at 3 days after stroke. Results: The expression of microglial EZH2 was significantly abrogated in KO mice compared to the control floxed mice (144±15.43 vs. 50.65±4.99 cells/mm 2 , N=5/each group, P<0.01). EZH2 deletion reduced brain infarct volume (29.27±2.23% vs. 6.07±0.88%, N=7/each group, P<0.001) and improved functional outcome assayed by adhesive removal test (59±13.1 sec, N=7 in floxed control vs. 26.28±4.1 sec, N=12 in KO, P<0.01). Mechanistically, microglial EZH2 deletion led to a decrease in expression of M1 marker iNOS (170±14.78 vs. 76.65±11.38 cells/mm 2 , N=4/each group, P<0.05), an increase in M2 marker Arg1 (96.64±11.48 vs. 203.3±22.02 cells/mm 2 , N=4/each group, P<0.05) co-stained in microglia (Iba1). Finally, GSK343 treatment robustly reduced infarct volume (37.1±2.97% vs. 21.9±2.92%) and increased latency to fall in hang-wire test (23.5±3.5 vs. 45.9±7.1 sec) (N=8/group, p<0.05) 3 days after stroke. Conclusions: Both genetic deletion of EZH2 in microglia and pharmacological inhibition of EZH2 improved stroke outcome in aged. The effect may be due to limiting microglial M1 polarization and enhancing M2 polarization.

Minocycline Promotes Functional Recovery in Ischemic Stroke by Modulating Microglia Polarization Through STAT1/STAT6 Pathways

2021 ◽  
Author(s):  
Yunnan Lu ◽  
Mingming Zhou ◽  
Yun Li ◽  
Yan Li ◽  
Ye Hua ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Functional Recovery ◽  
Neuronal Injury ◽  
Reactive Gliosis ◽  
Rotarod Test ◽  
M2 Microglia ◽  
Microglia Polarization ◽  
M1 Phenotype ◽  
Corner Turning ◽  
Turning Test

Abstract BackgroundIncreasing evidence suggests that microglia experience two distinct phenotypes after acute ischemic stroke (AIS): a deleterious M1 phenotype and a neuroprotective M2 phenotype. Promoting the phenotype shift of M1 microglia to M2 microglia is thought to improve functional recovery after AIS. Minocycline, a tetracycline antibiotic, can improve functional recovery after cerebral ischemia in pre-clinical and clinical research. However, the role and mechanisms of minocycline in microglia polarization is unclear.MethodsUsing the transient middle cerebral artery occlusion - reperfusion (MCAO/R) model, we treated mice with saline or different minocycline concentration (10, 25, or 50 mg/kg, i.p., daily for 2 wk) at 24 h after reperfusion. Neurobehavioral evaluation, rotarod test, and corner turning test were carried out on day 14 after reperfusion. Then, neuronal injury, reactive gliosis, and microglia polarization were performed on day 7 following MCAO/R. Finally, we treated primary microglial cultures with LPS (Lipopolysaccharide; 100 ng/mL) plus IFN-γ (20 ng/mL) 24 h to induce M1 phenotype and observed the effects of minocycline on the M1/M2-related mRNAs and the STAT1/STAT6 pathway.ResultsWe found that a 14-day treatment with minocycline increased the survival rate and promoted functional outcomes evaluated with neurobehavioral evaluation, rotarod test, and corner turning test. Meanwhile, minocycline reduced the brain infarct volume, alleviated neuronal injury, and suppressed reactive gliosis on day 7 following MCAO/R. Moreover, we observed an additive effect of minocycline on microglia polarization to the M1 and M2 phenotypes in vivo and in vitro. In the primary microglia, we further found that minocycline prevented neurons from OGD/R-induced cell death in neuron-microglia co-cultures via regulating M1/M2 microglia polarization through the STAT1/STAT6 pathway. ConclusionMinocycline promoted microglial M2 polarization and inhibited M1 polarization, leading to neuronal survival and neurological functional recovery. The findings deepen our understanding of the mechanisms underlying minocycline-mediated neuroprotection in AIS.

Abstract 520: High-density Lipoprotein Inhibits Human M1 Macrophage Polarisation through the Redistribution of Caveolin-1

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Man K Lee ◽  
Xiao-Lei Moore ◽  
Yi Fu ◽  
Annas Al-sharea ◽  
Dragana Dragoljeic ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Cholesterol Efflux ◽  
Human Macrophage ◽  
Ros Production ◽  
Oxygen Species ◽  
M1 Macrophages ◽  
Macrophage Polarisation ◽  
Caveolin 1 ◽  
M1 Phenotype ◽  
M2 Phenotype

Macrophages play a critical role in the development and progression of atherosclerosis. Depending on their surrounding milieu, macrophages can adopt a wide range of functional phenotypes; pro-inflammatory (M1) and pro-resolving (M2). HDL has many cardio-protective properties including potent anti-inflammatory effects, largely through the removal of cholesterol from cells. It is currently not known if this extends to influencing human macrophage phenotypes. Thus, we aimed to investigate the effect of HDL on human macrophage polarisation. Human blood monocyte-derived macrophages were induced to either an M1-phenotype by incubation with LPS and IFN-γ or to an M2-phenotype with IL-4. Macrophages were differentiated in the presence or absence of human HDL and their phenotypes were characterised using cell surface markers, reactive oxygen species (ROS) production by flow cytometry, and mRNA expression by real-time PCR. Downstream signalling pathways were also explored. We discovered that HDL inhibited the induction to M1 as evidenced by a decrease in cell surface marker expression; CD192 and CD64. This was accompanied by a decreased expression of M1-associated inflammatory genes TNF-α, IL-6 and MCP-1. However, HDL had no effect on induction to the M2 phenotype. Similarly, methyl-beta-cyclodextrin (MβCD), a non-specific cholesterol acceptor was also able to suppress M1 induction suggesting cholesterol efflux is important in this process. Further we found that HDL decreased membrane caveolin-1 in M1 macrophages and redistributed it intracellularly. The requirement of caveolin-1 was revealed as bone marrow-derived macrophages from Cav-1-/- mice continued to differentiate into M1 despite the addition of HDL. Moreover, we demonstrated a decrease in STAT3 and ERK1/2 phosphorylation in M1 macrophages treated with HDL, suggesting cholesterol efflux inhibits the STAT3s and MAPKs during induction to the M1 phenotype. Finally, we found that HDL also inhibited M1 function; with reduced reactive oxygen species (ROS) production. We provide evidence that HDL reduces macrophage induction to the inflammatory M1 phenotype, but not M2, via cellular redistribution of caveolin-1 and inactivation of STAT3 and ERK1/2 signalling pathway.

Treatment targets for M2 microglia polarization in ischemic stroke

2018 ◽  
Vol 105 ◽  
pp. 518-525 ◽  
Author(s):  
Ji wang ◽  
Hongyi xing ◽  
Lin wan ◽  
Xingjun jiang ◽  
Chen wang ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Treatment Targets ◽  
M2 Microglia ◽  
Microglia Polarization

scholarly journals Inhibited CSF1R Alleviates Ischemia Injury via Inhibition of Microglia M1 Polarization and NLRP3 Pathway

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Xiaoxue Du ◽  
Yuzhen Xu ◽  
Shijia Chen ◽  
Marong Fang
Keyword(s):  
Treatment Group ◽  
Neurological Diseases ◽  
Cerebral Stroke ◽  
Mice Model ◽  
Neuron Death ◽  
Triphenyltetrazolium Chloride ◽  
Neurobehavioral Function ◽  
M2 Microglia ◽  
M1 Polarization ◽  
Rota Rod Test

Ischemia cerebral stroke is one of the common neurological diseases with severe inflammatory response and neuron death. The inhibition of colony-stimulating factor 1 receptor (CSF1R) which especially expressed in microglia/macrophage exerted neuroprotection in stroke. However, the underlying neuroinflammatory regulation effects of CSF1R in ischemia stroke are not clear. In this study, cerebral ischemia stroke mice model was established. The C57/B6J mice were administered with Ki20227, a CSF1R inhibitor, by gavage for 7 consecutive days (0.002 mg/kg/day) before modeling. The Rota-Rod test and neurobehavioral score test were investigated to assess neurobehavioral functions. The area of infarction was assessed by 2, 3, 5-triphenyltetrazolium chloride (TTC) staining. The mRNA expressions of M1/M2 microglia markers were evaluated by real-time PCR. Immunofluorescence and Western blot were utilized to detect the changes of Iba1 and NLRP3 pathway proteins. Results showed that neurobehavioral function improvement was demonstrated by an increased stay time on the Rota-Rod test and a decreased neurobehavioral score in the Ki20227 treatment group. The area of infarction reduced in Ki20227 group when compared to the stroke group. Moreover, the mRNA expression of M1 microglia markers (TNF-α and iNOS) decreased while M2 microglia markers (IL-10 and Arg-1) increased. Meanwhile, compared to the stroke and stroke+PBS group, Ki20227 administration downregulated the expression of NLRP3, active caspase 1, and NF-κB protein in the ischemia penumbra of Ki20227 treatment group mice. In short, the CSF1R inhibitor, Ki20227, played vital neuroprotective roles in ischemia cerebral stroke mice, and the mechanisms may be via inhibiting microglia M1 polarization and NLRP3 inflammasome pathway activation. Our study provides a potential new target for the treatment of ischemic stroke injury.

scholarly journals Local Administration of Caloric Restriction Mimetics to Promote the Immune Control of Lung Metastases

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Valentino Le Noci ◽  
Michele Sommariva ◽  
Francesca Bianchi ◽  
Tiziana Triulzi ◽  
Elda Tagliabue ◽  
...  
Keyword(s):  
Weight Loss ◽  
Caloric Restriction ◽  
Lung Metastases ◽  
Pcr Analysis ◽  
Local Administration ◽  
Antitumor Effects ◽  
Lung Structure ◽  
Collateral Effects ◽  
M1 Phenotype

Caloric restriction mimetics (CRMs), compounds that mimic the biochemical effects of nutrient deprivation, administered via systemic route promote antitumor effects through the induction of autophagy and the modulation of the immune microenvironment; however, collateral effects due to metabolic changes and the possible weight loss might potentially limit their administration at long term. Here, we investigated in mice local administration of CRMs via aerosol to reduce metastasis implantation in the lung, whose physiologic immunosuppressive status favors tumor growth. Hydroxycitrate, spermidine, and alpha-lipoic acid, CRMs that target different metabolic enzymes, administered by aerosol, strongly reduced implantation of intravenously injected B16 melanoma cells without overt signs of toxicity, such as weight loss and changes in lung structure. Cytofluorimetric analysis of lung immune infiltrates revealed a significant increase of alveolar macrophages and CD103+ dendritic cells in mice treated with CRMs that paralleled an increased recruitment and activation of both CD3 T lymphocytes and NK cells. These effects were associated with the upregulation of genes related to M1 phenotype, as IL-12 and STAT-1, and to the decrease of M2 genes, as IL-10 and STAT-6, in adherent fraction of lung immune infiltrate, as revealed by real-time PCR analysis. Thus, in this proof-of-principle study, we highlight the antitumor effect of CRM aerosol delivery as a new and noninvasive therapeutic approach to locally modulate immunosurveillance at the tumor site in the lung.

scholarly journals Polarization of M2 macrophages requires Lamtor1 that integrates cytokine and amino-acid signals

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Tetsuya Kimura ◽  
Shigeyuki Nada ◽  
Noriko Takegahara ◽  
Tatsusada Okuno ◽  
Satoshi Nojima ◽  
...  
Keyword(s):  
Amino Acid ◽  
Macrophage Activation ◽  
Adaptor Protein ◽  
M2 Macrophages ◽  
Downstream Target ◽  
Mechanistic Target Of Rapamycin ◽  
M2 Polarization ◽  
M1 Polarization ◽  
Amino Acid Sensing ◽  
M1 And M2 Macrophages

Abstract Macrophages play crucial roles in host defence and tissue homoeostasis, processes in which both environmental stimuli and intracellularly generated metabolites influence activation of macrophages. Activated macrophages are classified into M1 and M2 macrophages. It remains unclear how intracellular nutrition sufficiency, especially for amino acid, influences on macrophage activation. Here we show that a lysosomal adaptor protein Lamtor1, which forms an amino-acid sensing complex with lysosomal vacuolar-type H+-ATPase (v-ATPase), and is the scaffold for amino acid-activated mTORC1 (mechanistic target of rapamycin complex 1), is critically required for M2 polarization. Lamtor1 deficiency, amino-acid starvation, or inhibition of v-ATPase and mTOR result in defective M2 polarization and enhanced M1 polarization. Furthermore, we identified liver X receptor (LXR) as the downstream target of Lamtor1 and mTORC1. Production of 25-hydroxycholesterol is dependent on Lamtor1 and mTORC1. Our findings demonstrate that Lamtor1 plays an essential role in M2 polarization, coupling immunity and metabolism.

Panax notoginseng Inhibits Tumor Growth through Activating Macrophage to M1 Polarization

2018 ◽  
Vol 46 (06) ◽  
pp. 1369-1385 ◽  
Author(s):  
Bosung Kim ◽  
Eun-Yeong Kim ◽  
Eun-Ji Lee ◽  
Jung Ho Han ◽  
Chung-Hwan Kwak ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Culture Media ◽  
Tumor Model ◽  
Annexin V ◽  
Panax Notoginseng ◽  
Raw264.7 Cells ◽  
M1 Polarization ◽  
Chemotactic Protein ◽  
M1 Phenotype

Among the herbal ingredients of HangAmDan-B, a medicinal formula that redirects macrophages to become tumoricidal effectors, we found that Panax notoginseng (Burk.) F. H. Chen is the active component responsible for its macrophage-mediated antitumor activity. The water extracted roots of P. notoginseng (PN) did not affect the viability of RAW264.7 murine macrophage-like cells and murine Lewis lung carcinoma (LLC) cells up to a concentration of 100[Formula: see text][Formula: see text]g/mL. However, the transfer of culture media from PN-treated RAW264.7 cells suppressed the growth of LLC cells. The expression of classically activated (M1) markers, such as interleukin (IL)-1[Formula: see text], monocyte chemotactic protein (MCP)-1, tumor necrosis factor (TNF)-[Formula: see text], and inducible nitric oxide synthase (iNOS), was increased by PN treatment. The expression of alternatively activated (M2) markers including CD206, IL-10, and [Formula: see text]-[Formula: see text]-acetylhexosaminidases (YM-1) was reduced by PN treatment in the presence of IL-4. Flow cytometry also revealed that PN drives M1 activation of RAW264.7 cells. The transfer of culture media from PN-treated RAW264.7 cells induced the apoptosis of LLC cells as measured by flow cytometry using Annexin-V staining and western blot analysis for caspase cascade-related proteins. In addition, the results from in vivo tumor allograft model demonstrated that PN reduced both tumor volume and weight. The activation of macrophages toward an M1 phenotype was confirmed in the tumor allograft tumor model. These results collectively show that PN can serve as a potent anticancer agent through reeducation of macrophages toward an M1 phenotype.

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