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.

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.

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.

scholarly journals Improved Promotion of M2 Microglial Polarization by Zuogui Jiangtang Jieyu Formulation in Diabetes-Related Depression

2021 ◽  
Author(s):  
xiuli zhang ◽  
Dahua Wu ◽  
Dandan Li ◽  
Jian Liu ◽  
Chang Lei ◽  
...  
Keyword(s):  
Inflammatory Cytokines ◽  
High Glucose ◽  
Neuroprotective Effect ◽  
Enzyme Linked Immunosorbent Assay ◽  
Mild Stress ◽  
Microglial Polarization ◽  
M2 Polarization ◽  
M1 Polarization

Abstract Background Zuogui Jiangtang Jieyu formulation (ZGJTJY) is a Chinese polyherbal prescription for diabetes-related depression (DD). The mechanism underlying hippocampal M1/M2 polarization in DD and the ZGJTJY treatment effects remain unclear. This study aimed to investigate M1/M2 microglial polarization in the hippocampus of DD rats and HAPI (highly aggressively proliferating immortalized) cells simulating the DD state, as well as to examine the ZGJTJY intervention effects, both in vivo and in vitro. Methods We subjected Sprague Dawley rats to a high-fat diet, streptozotocin, and unpredictable chronic mild stress; subsequently, we orally administered ZGJTJY. HAPI cells were induced using high glucose and corticosterone; subsequently, ZGJTJY-containing serum was added to examine changes in M1/M2 microglial polarization. Moreover, metformin combined with fluoxetine (DMGB/F) was used as a positive drug for evaluating the ZGJTJY intervention. Laser confocal scanning was used to examine the microglial morphology. Further, real-time PCR was used to determine M1 markers (MHCII, iNOS, MCP-1, CD11b), M2 markers (Arg1, Mrc1, Ym1), pro-inflammatory cytokines (IL-1β, IL-6, TNF-α), and anti-inflammatory cytokines (IL-4, IL-10). Additionally, an enzyme-linked immunosorbent assay was used to examine inflammatory cytokines. Results There was significant activation of M1 polarization in the hippocampus of DD rats and HAPI cells induced using high glucose and corticosterone. Compared with DMGB/F, ZGJTJY inhibited and promoted M1 and M2 polarization, respectively; moreover, it decreased the M1-to-M2 polarization ratio both in vivo and in vitro. Conclusions The study indicated that hippocampal M1 polarization is crucially involved in DD pathogenesis; moreover, there is a need for further research on the neuroprotective effect of Chinese medicine associated with M2-polarized microglia.

scholarly journals (-)-Epigallocatechin-3-gallate (EGCG) modulates polarized macrophages to suppress M1 phenotype and promote M2 polarization in vitro and in vivo

2021 ◽  
Vol 87 ◽  
pp. 104743
Author(s):  
Yaozhong Hu ◽  
Jiaxin Gu ◽  
Jing Lin ◽  
Yi Wang ◽  
Feier Yang ◽  
...  
Keyword(s):  
M2 Polarization ◽  
M1 Phenotype

scholarly journals SHED-Derived Exosomes Regulate Microglial Polarization in the Treatment of Traumatic Brain Injury in Rats via miR-330-5p

2020 ◽  
Author(s):  
Ye Li ◽  
Xinxin Wang ◽  
Xiaoyu Cao ◽  
Na Li ◽  
Sun Meng ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Structural Damage ◽  
Inhibitory Effect ◽  
Deciduous Teeth ◽  
Luciferase Reporter ◽  
Enzyme Linked Immunosorbent Assay ◽  
M2 Polarization ◽  
M1 Polarization

Abstract Background: Traumatic brain injury (TBI) causes structural damage and impairs motor and cognitive function of the brain. Our previous study suggested that exosomes (EXs) secreted by stem cells from human exfoliated deciduous teeth (SHED) extenuated motor damage in TBI rats by regulating microglia. The molecular mechanism of SHED-EXs was investigated in the present study. Methods: The miRNA array was performed to determine the differential miRNA expression in SHED-EXs treating microglia. The key miRNA was selected. Flow cytometry, immunofluorescence, enzyme linked immunosorbent assay (ELISA) and Griess assay were performed to detect the function of key miRNA. Real-time PCR, Western blotting and dual luciferase reporter assay were used to confirm the relationship between key miRNA and the target gene. Chromatin immunoprecipitation (ChIP) was performed to determine the downstream pathway of EXs-miRNA. Traumatic brain injury rat model was established and local injection of EXs-miRNA was performed to evaluate the effect.Results: SHED-EXs delivery of miR-330-5p was the key in the regulation of microglia polarization by inhibiting M1 polarization and promoting M2 polarization. Mechanistically, miR-330-5p had an inhibitory effect on Ehmt2, and miR-330-5p/Ehmt2 promoted the transcription of CXCL14 through H3K9me2. In vivo data showed that SHED-EXs/miR-330-5p reduced neuro-inflammation and repaired neurological function of TBI rats. Conclusions: SHED-EXs/miR-330-5p improved the motor function of rats after TBI by inhibiting M1 polarization and promoting M2 polarization of microglia through Ehmt2/H3K9me2/CXCL14 pathway.

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.

scholarly journals Quercetin prevents necroptosis of oligodendrocytes by inhibiting macrophages/microglia polarization to M1 phenotype after spinal cord injury in rats

2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Hong Fan ◽  
Hai-Bin Tang ◽  
Le-Qun Shan ◽  
Shi-Chang Liu ◽  
Da-Geng Huang ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
M1 Macrophages ◽  
Qrt Pcr ◽  
Cord Injury ◽  
Microglia Polarization ◽  
M1 Phenotype ◽  
Quercetin Treatment

Abstract Background Oligodendrocytes (OLs) death after spinal cord injury (SCI) contributes to demyelination, even leading to a permanent neurological deficit. Besides apoptosis, our previous study demonstrated that OLs underwent receptor-interacting serine-threonine kinase 3(RIP3)/mixed lineage kinase domain-like protein (MLKL)-mediated necroptosis. Considering that necroptosis is always accompanied with pro-inflammatory response and quercetin has long been used as anti-inflammatory agent, in the present study we investigated whether quercetin could inhibit necroptosis of OLs and suppress the M1 macrophages/microglia-mediated immune response after SCI as well as the possible mechanism. Methods In this study, we applied quercetin, an important flavonoid component of various herbs, to treat rats with SCI and rats injected with saline were employed as the control group. Locomotor functional recovery was evaluated using Basso-Beattie-Bresnahan (BBB) scoring and rump-height Index (RHI) assay. In vivo, the necroptosis, apoptosis, and regeneration of OLs were detected by immunohistochemistry, 5′-bromo-2′-deoxyuridine (BrdU) incorporation. The loss of myelin and axons after SCI were evaluated by Luxol fast blue (LFB) staining, immunohistochemistry, and electron microscopic study. The polarization of macrophages/microglia after SCI and the underlying mechanisms were detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and immunohistochemistry. In vitro, the ATP and reactive oxygen species (ROS) level examination, propidium iodide (PI) labeling, and Western blotting were used to analyze the necroptosis of cultured OLs, while the signaling pathways-mediated polarization of cultured macrophages/microglia was detected by qRT-PCR and Western blotting. Results We demonstrated that quercetin treatment improved functional recovery in rats after SCI. We then found that quercetin significantly reduced necroptosis of OLs after SCI without influencing apoptosis and regeneration of OLs. Meanwhile, myelin loss and axon loss were also significantly reduced in quercetin-treated rats, as compared to SCI + saline control. Further, we revealed that quercetin could suppress macrophages/microglia polarized to M1 phenotype through inhibition of STAT1 and NF-κB pathway in vivo and in vitro, which contributes to the decreased necroptosis of OLs. Conclusions Quercetin treatment alleviated necroptosis of OLs partially by inhibiting M1 macrophages/microglia polarization after SCI. Our findings suggest that necroptosis of OLs may be a potential therapeutic target for clinical SCI.

scholarly journals Extracellular vesicles-transmitted miR-21a-5p altered microglia polarization after hypoxia-ischemic injury in neonatal mice via STAT3 pathways

2021 ◽  
Author(s):  
Danqing Xin ◽  
Yijing Zhao ◽  
Tingting Li ◽  
Hongfei Ke ◽  
Chengcheng Gai ◽  
...  
Keyword(s):  
Brain Injury ◽  
Brain Damage ◽  
Extracellular Vesicles ◽  
Luciferase Reporter ◽  
Neonatal Mice ◽  
M2 Polarization ◽  
Stat3 Phosphorylation ◽  
Microglia Polarization

Abstract Background We previously reported that mesenchymal stromal cells (MSCs)-derived extracellular vesicles (EVs) exhibit protective effects in hypoxia-ischemia (HI) brain damage. The neuroprotective action was connected with its anti-inflammatory effect. However, the mechanisms involved with this effect have not been determined. Methods A modified version of the Rice-Vannucci method was performed on postnatal day 7 mouse pups to induce neonatal HI brain injury. The model of oxygen-glucose deprivation (OGD) was established in BV-2 cells to mimic HI injury in vitro. Mice or BV-2 cells received EVs and EVs-miR-21ainhibitor at indicative time post-injury. In vivo, brain water content and TTC staining were used to evaluate the effects of EVs on HI brain injury. Immunofluorescence staining was used to observe the effect of EVs on the polarization of microglia. The effect of EVs on p-STAT3 was assessed by Western blot. In vitro, the effect of EVs on cell survival was evaluated by CCK8. Expression of miR-21a-5p and inflammatory factors was measured using qRT-PCR. Dual-Luciferase Reporter Assay was performed to illustrate the link between miR-21a-5p and STAT3. The role of miR-21a-5p in EVs on HI injury and ODG injury was further investigated by using EVs-miR-21ainhibitor.Results By using OGD mimicking HI injury in vitro, we found that MSCs-EVs treatment elevated cell viability following OGD exposure in BV-2 cells. MSCs-EVs treatment impeded microglia-mediated neuroinflammation, shifted microglia toward M2 polarization, and suppressed the phosphorylation of selective signal transducer and activator of transcription 3 (STAT3) in microglia after HI exposure in vitro and in vivo. In light of miR-21a-5p being the most highly expressed miRNA in MSCs-EVs interacting with the STAT3 pathway, further work focused on this pathway. Notably, MSCs-EVs treatment increased HI-reduced miR-21a-5p levels in BV-2 cells. Diminishing miR-21a-5p in MSCs-EVs partially attenuated its effect on microglia polarization and STAT3 phosphorylation following HI exposure in vitro and in vivo. Conclusions Our study suggested that MSCs-EVs attenuated HI brain damage in neonatal mice via shuttling miR-21a-5p, which induced microglia M2 polarization by targeting STAT3.

scholarly journals Green Phellodendri Chinensis Cortex-based carbon dots for ameliorating imiquimod-induced psoriasis-like inflammation in mice

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Meiling Zhang ◽  
Jinjun Cheng ◽  
Jie Hu ◽  
Juan Luo ◽  
Yue Zhang ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Carbon Dots ◽  
Severity Index ◽  
X Ray ◽  
M2 Polarization ◽  
M1 Polarization ◽  
Calcination Method ◽  
Chemical Groups

Abstract Background Carbon dots (CDs) with multifaceted advantages have provided hope for development brand-new nanodrug for treating thorny diseases. This study developed a green and simple calcination method to prepare novel CDs as promising drug for psoriasis treatment. The as-prepared CDs using Phellodendri Chinensis Cortex (PCC) as sole precursor were characterized by a series of methods, mainly including electron microscopy, optical technology and X-ray photoelectron spectroscopy (XPS). Results Results displayed that fluorescence (Quantum yield = 5.63%) and nontoxic PCC-based CDs (PCC-CDs) with abundant chemical groups exhibited solubility and tiny sizes at average of (1.93 ± 0.53) nm, which may be beneficial for its inherent biological activity. Moreover, by using the typical imiquimod (IMQ)-induced psoriasis-like skin mouse model, we firstly demonstrated the pronounced anti-psoriasis activity of as-prepared PCC-CDs on ameliorating the appearance, psoriasis area and severity index (PASI) scores as well as histopathological morphology of both back skin tissues and right ears in IMQ-induced mouse. Further potential mechanisms behind the anti-psoriasis activities may be related to suppress M1 polarization and relatively promote M2 polarization of macrophage both in vitro and in vivo. Conclusion These results suggested that PCC-CDs have potential to be an anti-psoriasis candidate for clinical applications to treat psoriasis, which not only provided an evidence for further broadening the biological application of CDs, but also provided a potential hope for application nanodrugs to treat thorny diseases. Graphic Abstract

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