Shuxuetong injection protects cerebral microvascular endothelial cells against oxygen-glucose deprivation reperfusion

Shuxuetong injection composed of leech(Hirudo nipponica Whitman) and earthworm(Pheretima aspergillum) has been used for the clinical treatment of acute stroke for many years in China. However, the precise neuroprotective mechanism of Shuxuetong injection remains poorly understood. Here, cerebral microvascular endothelial cells(bEnd.3) were incubated in glucose-free Dulbecco's modified Eagle's medium containing 95% N_2/5% CO_2 for 6 hours, followed by high-glucose medium containing 95% O_2 and 5% CO_2 for 18 hours to establish an oxygen-glucose deprivation/reperfusion model. This in vitro cell model was administered Shuxuetong injection at 1/32, 1/64, and 1/128 concentrations(diluted 32-, 64-, and 128-times). Cell Counting Kit-8 assay was used to evaluate cell viability. A fluorescence method was used to measure lactate dehydrogenase, and a fluorescence microplate reader used to detect intracellular reactive oxygen species. A fluorescent probe was also used to measure mitochondrial superoxide production. A cell resistance meter was used to measure transepithelial resistance and examine integrity of monolayer cells. The fluorescein isothiocyanate-dextran test was performed to examine blood-brain barrier permeability. Real-time reverse transcription polymerase chain reaction was performed to analyze mRNA expression levels of tumor necrosis factor alpha, interleukin-1β, interleukin-6, and inducible nitric oxide synthase. Western blot assay was performed to analyze expression of caspase-3, intercellular adhesion molecule 1, vascular cell adhesion molecule 1, occludin, vascular endothelial growth factor, cleaved caspase-3, B-cell lymphoma 2, phosphorylated extracellular signal-regulated protein kinase, extracellular signal-regulated protein kinase, nuclear factor-κB p65, I kappa B alpha, phosphorylated I kappa B alpha, I kappa B kinase, phosphorylated I kappa B kinase, claudin-5, and zonula occludens-1. Our results show that Shuxuetong injection increases bEnd.3 cell viability and B-cell lymphoma 2 expression, reduces cleaved caspase-3 expression, inhibits production of reactive oxygen species and mitochondrial superoxide, suppresses expression of tumor necrosis factor alpha, interleukin-1β, interleukin-6, inducible nitric oxide synthase mRNA, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1, markedly increases transepithelial resistance, decreases blood-brain barrier permeability, upregulates claudin-5, occludin, and zonula occludens-1 expression, reduces nuclear factor-κB p65 and vascular endothelial growth factor expression, and reduces I kappa B alpha, extracellular signal-regulated protein kinase 1/2, and I kappa B kinase phosphorylation levels. Overall, these findings suggest that Shuxuetong injection has protective effects on brain microvascular endothelial cells after oxygen-glucose deprivation/reperfusion. Moreover, its protective effect is associated with reduction of mitochondrial superoxide production, inhibition of the inflammatory response, and inhibition of vascular endothelial growth factor, extracellular signal-regulated protein kinase 1/2, and the nuclear factor-κB p65 signaling pathway.

Silencing Huwe1 reduces apoptosis of cortical neurons exposed to oxygen-glucose deprivation and reperfusion

HECT, UBA and WWE domain-containing 1(Huwe1), an E3 ubiquitin ligase involved in the ubiquitin-proteasome system, is widely expressed in brain tissue. Huwe1 is involved in the turnover of numerous substrates, including p53, Mcl-1, Cdc6 and N-myc, thereby playing a critical role in apoptosis and neurogenesis. However, the role of Huwe1 in brain ischemia and reperfusion injury remains unclear. Therefore, in this study, we investigated the role of Huwe1 in an in vitro model of ischemia and reperfusion injury. At 3 days in vitro, primary cortical neurons were transduced with a control or shRNA-Huwe1 lentiviral vector to silence expression of Huwe1. At 7 days in vitro, the cells were exposed to oxygen-glucose deprivation for 3 hours and reperfusion for 24 hours. To examine the role of the c-Jun N-terminal kinase(JNK)/p38 pathway, cortical neurons were pretreated with a JNK inhibitor(SP600125) or a p38 MAPK inhibitor(SB203508) for 30 minutes at 7 days in vitro, followed by ischemia and reperfusion. Neuronal apoptosis was assessed by TUNEL assay. Protein expression levels of JNK and p38 MAPK and of apoptosis-related proteins(p53, Gadd45 a, cleaved caspase-3, Bax and Bcl-2) were measured by western blot assay. Immunofluorescence labeling for cleaved caspase-3 was performed. We observed a significant increase in neuronal apoptosis and Huwe1 expression after ischemia and reperfusion. Treatment with the shRNA-Huwe1 lentiviral vector markedly decreased Huwe1 levels, and significantly decreased the number of TUNEL-positive cells after ischemia and reperfusion. The silencing vector also downregulated the pro-apoptotic proteins Bax and cleaved caspase-3, and upregulated the anti-apoptotic proteins Gadd45 a and Bcl-2. Silencing Huwe1 also significantly reduced p-JNK levels and increased p-p38 levels. Our findings show that downregulating Huwe1 affects the JNK and p38 MAPK signaling pathways as well as the expression of apoptosis-related genes to provide neuroprotection during ischemia and reperfusion. All animal experiments and procedures were approved by the Animal Ethics Committee of Sichuan University, China in January 2018(approval No. 2018013).

Effects of extracellular vesicles from mesenchymal stem cells on oxygen-glucose deprivation/reperfusioninduced neuronal injury

BACKGROUND: Small extracellular vesicles (sEVs) from bone marrow mesenchymal stemcells (BMSCs) have shown therapeutic potential for cerebral ischemic diseases. However, themechanisms by which BMSC-derived sEVs (BMSC-sEVs) protect neurons against cerebral ischemia/reperfusion (I/R) injury remain unclear. In this study, we explored the neuroprotective effects ofBMSC-sEVs in the primary culture of rat cortical neurons exposed to oxygen-glucose deprivation andreperfusion (OGD/R) injury.METHODS: The primary cortical neuron OGD/R model was established to simulate the processof cerebral I/R in vitro. Based on this model, we examined whether the mechanism through whichBMSC-sEVs could rescue OGD/R-induced neuronal injury.RESULTS: BMSC-sEVs (20 μg/mL, 40 μg/mL) significantly decreased the reactive oxygenspecies (ROS) productions, and increased the activities of superoxide dismutase (SOD) and glutathioneperoxidase (GPx). Additionally, BMSC-sEVs prevented OGD/R-induced neuronal apoptosis in vivo, asindicated by increased cell viability, reduced lactate dehydrogenase (LDH) leakage, decreased terminaldeoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) staining-positivecells, down-regulated cleaved caspase-3, and up-regulated Bcl-2/Bax ratio. Furthermore, Westernblot and flow cytometry analysis indicated that BMSC-sEV treatment decreased the expression ofphosphorylated calcium/calmodulin-dependent kinase II (p-CaMK II)/CaMK II, suppressed the increaseof intracellular calcium concentration ([Ca2+]i) caused by OGD/R in neurons.CONCLUSIONS: These results demonstrate that BMSC-sEVs have signifi cant neuroprotectiveeff ects against OGD/R-induced cell injury by suppressing oxidative stress and apoptosis, and Ca2+/CaMK II signaling pathways may be involved in this process.

Protective effect of mesenchymal stem cell-derived exosomal treatment of hippocampal neurons against oxygen-glucose deprivation/reperfusion-induced injury

BACKGROUND:Individuals who survive a cardiac arrest often sustain cognitive impairments due to ischemia-reperfusion injury.Mesenchymal stem cell(MSC)transplantation is used to reduce tissue damage,but exosomes are more stable and highly conserved than MSCs.This study was conducted to investigate the therapeutic effects of MSC-derived exosomes(MSC-Exo)on cerebral ischemia-reperfusion injury in an in vitro model of oxygen-glucose deprivation/reperfusion(OGD/R),and to explore the underlying mechanisms.METHODS:Primary hippocampal neurons obtained from 18-day Sprague-Dawley rat embryos were subjected to OGD/R treatment,with or without MSC-Exo treatment.Exosomal integration,cell viability,mitochondrial membrane potential,and generation of reactive oxygen species(ROS)were examined.Terminal deoxynucleotidyl transferase-mediated 2’-deoxyuridine 5’-triphosphate nickend labeling(TUNEL)staining was performed to detect neuronal apoptosis.Moreover,mitochondrial function-associated gene expression,Nrf2 translocation,and expression of downstream antioxidant proteins were determined.RESULTS:MSC-Exo attenuated OGD/R-induced neuronal apoptosis and decreased ROS generation(P<0.05).The exosomes reduced OGD/R-induced Nrf2 translocation into the nucleus(2.14±0.65 vs.5.48±1.09,P<0.01)and increased the intracellular expression of antioxidative proteins,including superoxide dismutase and glutathione peroxidase(17.18±0.97 vs.14.40±0.62,and 20.65±2.23 vs.16.44±2.05,respectively;P<0.05 for both).OGD/R significantly impaired the mitochondrial membrane potential and modulated the expression of mitochondrial functionassociated genes,such as PINK,DJ1,LRRK2,Mfn-1,Mfn-2,and OPA1.The abovementioned changes were partially reversed by exosomal treatment of the hippocampal neurons.CONCLUSIONS:MSC-Exo treatment can alleviate OGD/R-induced oxidative stress and dysregulation of mitochondrial function-associated genes in hippocampal neurons.Therefore,MSCExo might be a potential therapeutic strategy to prevent OGD/R-induced neuronal injury.

Neuroprotective effect and mechanism of daidzein in oxygen-glucose deprivation/reperfusion injury based on experimental approaches and network pharmacology

Background:Daidzein,phytoestrogens derived from the Pueraria lobata(Willd.)Ohwi root used in traditional Chinese medicine,has a wide range of biological activities,including antioxidant,anti-inflammatory,and neuroprotection.However,the neuroprotective role of daidzein in oxygen-glucose deprivation/reperfusion injury and its underlying mechanism are still unknown.Methods:In this study,we used pheochromocytoma cells induced by oxygen-glucose deprivation and reperfusion to study the potential effect in the protection of the nerve cells.Then,we used molecular docking simulation and network pharmacology to predict the possible targets and pharmacological pathways of daidzein.Western blot was used to verify the expression of target proteins with or without adding the inhibitors.Results:After daidzein treatment,cell vitality had an upward trend(P<0.05)and the release of lactate dehydrogenase had a downward trend(P<0.01)in dose-dependent compared with the model group by exposure to oxygen-glucose deprivation and reperfusion.Several core targets were analyzed through network pharmacology and molecular docking including catalase,peroxisome proliferator-activated receptor gamma,vascular endothelial growth factor A,interleukin-6,tumor necrosis factor,nitric oxide synthase 3,prostaglandin-endoperoxide synthase 2,and RAC-alpha serine/threonine kinase 1.These results suggest that catalase may be a first-ranked target for the neuroprotective role of daidzein.Gene Ontology enrichment analysis indicated the pathways mainly contained molecule metabolic process,while Kyoto Encyclopedia of Genes and Genomes enrichment analysis focus on pathways in terms of inflammation such as tumor necrosis factor signal pathway.Then,Western blot results showed that daidzein had a significant increase on the expression of protein catalase(P<0.01).Daidzein reversed catalase level alterations after oxygen-glucose deprivation reperfusion injury in a dose-dependent manner which was consistent with the catalase antagonists-based experiments.Conclusion:These outcomes provide new insights into the neuroprotective effect and mechanism of daidzein in oxygen-glucose deprivation/reperfusion injury.

Intervention Timing and Effect of PJ34 on Astrocytes During Oxygen-glucose Deprivation/reperfusion and Cell Death Pathways

Poly （ADP-ribose） polymerase-I （PARP-1） plays as a double edged sword in cerebral ischemia-reperfusion, hinging on its effect on the intracellular energy storage and injury severity, and the prognosis has relationship with intervention timing. During ischemia injury, apoptosis and oncosis are the two main cell death pathway sin the ischemic core. The participation of astrocytes in ische- mia-reperfusion induced cell death has triggered more and more attention. Here, we examined the pro- tective effects and intervention timing of the PARP-1 inhibitor PJ34, by using a mixed oxygen-glucose deprivation/reperfusion （OGDR） model of primary rat astrocytes in vitro, which could mimic the ische- mia-reperfusion damage in the ＂ischemic core＂. Meanwhile, cell death pathways of various P J34 treated astrocytes were also investigated. Our results showed that P J34 incubation （10 μmol/L） did not affect release of lactate dehydrogenase （LDH） from astrocytes and cell viability or survival 1 h after OGDR. Interestingly, after 3 or 5 h OGDR, P J34 significantly reduced LDH release and percentage of PI-positive cells and increased cell viability, and simultaneously increased the caspase-dependent apop- totic rate. The intervention timing study demonstrated that an earlier and longer P J34 intervention dur- ing reperfusion was associated with more apparent protective effects. In conclusion, earlier and longer PJ34 intervention provides remarkable protective effects for astrocytes in the ＂ischaemic core＂ mainly by reducing oncosis of the astrocytes, especially following serious OGDR damage.

Dynamic changes in proprotein convertase 2 activity in cortical neurons after ischemia/reperfusion and oxygen-glucose deprivation

In this study, a rat model of transient focal cerebral ischemia was established by performing 100 minutes of middle cerebral artery occlusion, and an in vitro model of experimental oxygen-glucose deprivation using cultured rat cortical neurons was established. Proprotein convertase 2 activity gradually decreased in the ischemic cortex with increasing duration of reperfusion. In cultured rat cortical neurons, the number of terminal deoxynucleotidyl transferase-mediated 2＇-deoxyuridine 5＇-triphosphate-biotin nick end labeling-positive neurons significantly increased and proprotein convertase 2 activity also decreased gradually with increasing duration of oxygen-glucose deprivation. These experimental findings indicate that proprotein convertase 2 activity decreases in ischemic rat cortex after reperfusion, as well as in cultured rat cortical neurons after oxygen-glucose deprivation. These changes in enzyme activity may play an important pathological role in brain injury.

Curcumin pretreatment and post-treatment both improve the antioxidative ability of neurons with oxygen-glucose deprivation

Recent studies have shown that induced expression of endogenous antioxidative enzymes thr- ough activation of the antioxidant response element/nuclear factor erythroid 2-related factor 2 （Nrf2） pathway may be a neuroprotective strategy. In this study, rat cerebral cortical neurons cultured in vitro were pretreated with 10 ktM curcumin or post-treated with 5 pM curcumin, respectively before or after being subjected to oxygen-glucose deprivation and reoxygenation for 24 hours. Both pretreatment and post-treatment resulted in a significant decrease of cell injury as indicated by propidium iodide/Hoechst 33258 staining, a prominent increase of Nrf2 protein expression as indicated by western blot analysis, and a remarkable increase of protein expression and enzyme activity in whole cell lysates of thioredoxin before ischemia, after ischemia, and after reoxygenation. In addition, post-treatment with curcumin inhibited early DNA/RNA oxidation as indicated by immunocytochemistry and increased nuclear Nrf2 protein by inducing nuclear accumulation of Nrf2. These findings suggest that curcumin activates the expression of thi- oredoxin, an antioxidant protein in the Nrf2 pathway, and protects neurons from death caused by oxygen-glucose deprivation in an in vitro model of ischemia/reperfusion. We speculate that pharmacologic stimulation of antioxidant gene expression may be a promising approach to neu- roprotection after cerebral ischemia.

Rac1 relieves neuronal injury induced by oxygen-glucose deprivation and re-oxygenation via regulation of mitochondrial biogenesis and function

Certain microRNAs(miRNAs)can function as neuroprotective factors after reperfusion/ischemia brain injury.miRNA-142-3p can participate in the occurrence and development of tumors and myocardial ischemic injury by negatively regulating the activity of Rac1,but it remains unclear whether miRNA-142-3p also participates in cerebral ischemia/reperfusion injury.In this study,a model of oxygen-glucose deprivation/re-oxygenation in primary cortical neurons was established and the neurons were transfected with miR-142-3p agomirs or miR-142-3p antagomirs.miR-142-3p expression was down-regulated in neurons when exposed to oxygen-glucose deprivation/re-oxygenation.Over-expression of miR-142-3p using its agomir remarkably promoted cell death and apoptosis induced by oxygen-glucose deprivation/re-oxygenation and improved mitochondrial biogenesis and function,including the expression of peroxisome proliferator-activated receptor-γcoactivator-1α,mitochondrial transcription factor A,and nuclear respiratory factor 1.However,the opposite effects were produced if miR-142-3p was inhibited.Luciferase reporter assays verified that Rac Family Small GTPase 1(Rac1)was a target gene of miR-142-3p.Over-expressed miR-142-3p inhibited NOX2 activity and expression of Rac1 and Rac1-GTPase(its activated form).miR-142-3p antagomirs had opposite effects after oxygen-glucose deprivation/re-oxygenation.Our results indicate that miR-142-3p down-regulates the expression and activation of Rac1,regulates mitochondrial biogenesis and function,and inhibits oxygen-glucose deprivation damage,thus exerting a neuroprotective effect.The experiments were approved by the Committee of Experimental Animal Use and Care of Central South University,China(approval No.201703346)on March 7,2017.

The pathways by which mild hypothermia inhibits neuronal apoptosis following ischemia/reperfusion injury

Several studies have demonstrated that mild hypothermia exhibits a neuroprotective role and it can inhibit endothelial cell apoptosis following ischemia/reperfusion injury by decreasing casp- ase-3 expression, It is hypothesized that mild hypothermia exhibits neuroprotective effects on neurons exposed to ischemia/reperfusion condition produced by oxygen-glucose deprivation. Mild hypothermia significantly reduced the number of apoptotic neurons, decreased the expres- sion of pro-apoptotic protein Bax and increased mitochondrial membrane potential, with the peak of anti-apoptotic effect appearing between 6 and 12 hours after the injury. These findings indicate that mild hypothermia inhibits neuronal apoptosis following ischemia/reperfusion injury by protecting the mitochondria and that the effective time window is 6-12 hours after ischemia/reperfusion injury.

Vav1 promotes inflammation and neuronal apoptosis in cerebral ischemia/reperfusion injury by upregulating microglial and NLRP3 inflammasome activation

Microglia,which are the resident macrophages of the central nervous system,are an important part of the inflammatory response that occurs after cerebral ischemia.Vav guanine nucleotide exchange factor 1(Vav1) is a guanine nucleotide exchange factor that is related to microglial activation.However,how Vav1 participates in the inflammato ry response after cerebral ischemia/reperfusion inj ury remains unclea r.In this study,we subjected rats to occlusion and repe rfusion of the middle cerebral artery and subjected the BV-2 mic roglia cell line to oxygen-glucose deprivatio n/reoxygenation to mimic cerebral ischemia/repe rfusion in vivo and in vitro,respectively.We found that Vav1 levels were increased in the brain tissue of rats subjected to occlusion and reperfusion of the middle cerebral arte ry and in BV-2 cells subjected to oxygen-glucose deprivation/reoxygenation.Silencing Vav1 reduced the cerebral infarct volume and brain water content,inhibited neuronal loss and apoptosis in the ischemic penumbra,and im p roved neurological function in rats subjected to occlusion and repe rfusion of the middle cerebral artery.Further analysis showed that Vav1 was almost exclusively localized to microglia and that Vav1 downregulation inhibited microglial activation and the NOD-like receptor pyrin 3(NLRP3) inflammasome in the ischemic penumbra,as well as the expression of inflammato ry facto rs.In addition,Vov1 knoc kdown decreased the inflammatory response exhibited by BV-2 cells after oxygen-glucose deprivation/reoxyge nation.Taken together,these findings show that silencing Vav1 attenuates inflammation and neuronal apoptosis in rats subjected to cerebral ischemia/repe rfusion through inhibiting the activation of mic roglia and NLRP3 inflammasome.

Upregulation of CDGSH iron sulfur domain 2 attenuates cerebral ischemia/reperfusion injury

CDGSH iron sulfur domain 2 can inhibit ferroptosis,which has been associated with cerebral ischemia/reperfusion,in individuals with head and neck cancer.Therefore,CDGSH iron sulfur domain 2 may be implicated in cerebral ischemia/reperfusion injury.To validate this hypothesis in the present study,we established mouse models of occlusion of the middle cerebral artery and HT22 cell models of oxygen-glucose deprivation and reoxygenation to mimic cerebral ischemia/reperfusion injury in vivo and in vitro,respectively.We found remarkably decreased CDGSH iron sulfur domain 2 expression in the mouse brain tissue and HT22 cells.When we used adeno-associated virus and plasmid to up-regulate CDGSH iron sulfur domain 2 expression in the brain tissue and HT22 cell models separately,mouse neurological dysfunction was greatly improved;the cerebral infarct volume was reduced;the survival rate of HT22 cells was increased;HT22 cell injury was alleviated;the expression of ferroptosis-related glutathione peroxidase 4,cystine-glutamate antiporter,and glutathione was increased;the levels of malondialdehyde,iron ions,and the expression of transferrin receptor 1 were decreased;and the expression of nuclear-factor E2-related factor 2/heme oxygenase 1 was increased.Inhibition of CDGSH iron sulfur domain 2 upregulation via the nuclear-factor E2-related factor 2 inhibitor ML385 in oxygen-glucose deprived and reoxygenated HT22 cells blocked the neuroprotective effects of CDGSH iron sulfur domain 2 up-regulation and the activation of the nuclear-factor E2-related factor 2/heme oxygenase 1 pathway.Our data indicate that the up-regulation of CDGSH iron sulfur domain 2 can attenuate cerebral ischemia/reperfusion injury,thus providing theoretical support from the perspectives of cytology and experimental zoology for the use of this protein as a therapeutic target in patients with cerebral ischemia/reperfusion injury.

Icariside Ⅱ, a PDE5 inhibitor, attenuates cerebral ischemia/reperfusion injury through activating BDNF/TrkB/CREB signaling pathway

OBJECTIVE To explore the effects and mechanism of icariside Ⅱ(ICS Ⅱ),a pharmacologically active compound derived from herbal Epimedii with previous study-proved phosphodiesterase 5(PDE5) inhibitors,was investigated in vivo using a middle cerebral artery occlusion/reperfusion(MCAO/R) model in rats and in vitro using an oxygen-glucose deprivation/reperfusion(OGD/R) model in primary hippocampal neurons.METHODS Laser Doppler flowmeter was introduced to examine the cerebral blood flow of MCAO/R rats.The neurological deficits scores,brain water content and infarction volume were assessed after MCAO/R.OGD/R-induced primary hippocampal neuronal injury and apoptosis were examined by MTT,lactate dehydrogenase(LDH) release,TUNEL staining and flow cytometry,respectively.Expressions of PDE5 A and memory-related signaling pathways were measured using Western blotting analysis.The direct interaction between ICS Ⅱand PDE5 was further evaluated by molecular docking.RESULTS ICS Ⅱ significantly decreased the infraction volume in MCAO/R rats.Furthermore,ICS Ⅱ significantly abrogated OGD/R-induced hippocampal neuronal death.Moreover,ICSⅡ not only effectively restored the 3′ 5′-cyclic guanosine monophosphate(cGMP) level and protein kinase G(PKG) activity both in vivo and in vitro,but also increased brain-derived neurotrophic factor(BDNF),tyrosine protein kinase B(TrkB) and cAMP response element-binding protein(CREB) expressions,thereby inhibited hippocampal neuronal apoptosis.Mechanistically,the beneficial effects of ICS Ⅱ was attributed to its activation of the PKG/TrkB/BDNF via increasing BDNF expression,evidenced by that the inhibition effects of ICSⅡ was abrogated by Rp-8-BrcGMPS,a PKG inhibitor,or ANA-12,a TrkB inhibitor.ICSⅡ also decreased both protein level and activity of PDE5.Notably,ICSⅡ might effectively bind and inhibite PDE5 as demonstrated by relatively high binding score.CONCLUSION ICSⅡ significantly protect against cerebral ischemia/reperfusion injury in rats and rescues OGD/Rinduced hippocampal neuronal injury,and the underling mechanisms are,at least partly,due to inhibition of PDE5 and activation of BDNF/TrkB/CREB signaling pathway.Hence ICS Ⅱ may be an effective agent for combating cerebral ischemia/reperfusion injury.

Efficacy of Danlou tablet(丹蒌片)on myocardial ischemia/reperfusion injury assessed by network pharmacology and experimental verification

OBJECTIVE:To investigate the potential pharmacological mechanism of Danlou tablet(丹蒌片,DLT)with a long-term clinical application in the treatment of myocardial ischemia/reperfusion(I/R)injury through network pharmacology,molecular docking and experimental verification.METHODS:The main chemical ingredients in DLT were retrieved from the Traditional Chinese Medicine(TCM)System Pharmacology Database,the TCM information database,the bioinformatics analysis tool for molecular mechanism of TCM,and HERB database.Disease targets of I/R were accessed from the databases of Online Mendelian Inheritance in Man,Gene Cards,Therapeutic Target Database,and Dis Ge NET database.The overlaying genes of DLT and I/R were obtained from the Venny online platform.The core targets and proteinprotein interaction network were constructed and analyzed via the Search Tool for the Retrieval of Interacting Genes Proteins database and Cytoscape software.Furthermore,Gene Ontology(GO)analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment analysis were performed by the Metascape platform.Based on the results,the component-target-pathway network was constructed and drafted via the Cytoscape software and the platform of Bioinformatics.Furthermore,we performed molecular docking to predict the binding information between chemical molecules and target proteins.Finally,oxygenglucose deprivation/recovery(OGD/R)-induced H9c2 cardiomyocytes were used to validate the results of network pharmacology in vitro.RESULTS:A total of 189 active chemical components in DLT and 849 correlative targets of I/R were screened.Of note,133 overlaying genes found from the Venny online platform were concentrated into 28 core genes.Furthermore,the GO and KEGG pathway enrichment analysis presented that DLT might participate in 42 types of GO molecular functions,747 types of GO biological processes,19 types of GO cellular components,and 140 kinds of pathways to treat I/R.In the component-targetpathway network,the indirect relationship between herbs and their possible effective pathways was clarified.Based on the molecular docking,we speculated that Baicalein-prostaglandin G/H synthase 2(PTGS2)with-3.24 kcal/mol,Luteolin-heat shock protein 90 alpha family class A member 1(HSP90AA1)with-3.22 kcal/mol,Baicalein-HSP90AA1 with-3.13 kcal/mol,and QuercetinHSP90AA1 with-3.05 kcal/mol possessed the strongest binding force of less than-3 kcal/mol,sequentially.Experimental verification showed that Quercetin,Luteolin,and Baicalein could increase the relative cell viability of OGD/R-stimulated cardiomyocytes,probably by suppressing PTGS2,and activating HSP90AA1 and estrogen receptor 1 expression.CONCLUSIONS:We predicted the potential active compounds as the material basis of DLT that may provide a new approach to elucidate the novel pharmacological mechanism underlying the treatment of cardiac I/R damage.

LncRNA SNHG12 ameliorates brain microvascular endothelial cell injury by targeting miR-199a

Long non-coding RNAs regulate brain microvascular endothelial cell death, the inflammatory response and angiogenesis during and after ischemia/reperfusion and oxygen-glucose deprivation/reoxygenation（OGD/R） insults. The long non-coding RNA, SNHG12, is upregulated after ischemia/reperfusion and OGD/R in microvascular endothelial cells of the mouse brain. However, its role in ischemic stroke has not been studied. We hypothesized that SNHG12 positively regulates ischemic stroke, and therefore we investigated its mechanism of action. We established an OGD/R mouse cell model to mimic ischemic stroke by exposing brain microvascular endothelial cells to OGD for 0, 2, 4, 8, 16 or 24 hours and reoxygenation for 4 hours. Quantitative real-time polymerase chain reaction showed that SNHG12 levels in brain microvascular endothelial cells increased with respect to OGD exposure time. Brain microvascular endothelial cells were transfected with pc DNA-control, pc DNA-SNHG12, si-control, or si-SNHG12. After exposure to OGD for 16 hours, these cells were then analyzed by 3-（4,5-dimethyl-2-thiazolyl）-2,5-diphenyl-2-H-tetrazolium bromide, trypan blue exclusion, western blot, and capillary-like tube formation assays. Overexpression of SNHG12 inhibited brain microvascular endothelial cell death and the inflammatory response but promoted angiogenesis after OGD/R, while SNHG12 knockdown had the opposite effects. miR-199a was identified as a target of SNHG12, and SNHG12 overexpression reversed the effect of miR-199a on brain microvascular endothelial cell death, the inflammatory response, and angiogenesis. These findings suggest that SNHG12 suppresses endothelial cell injury induced by OGD/R by targeting miR-199a.

蛋白酶抑制剂H89对神经元细胞氧糖剥夺再灌注后高尔基体形态及细胞凋亡的影响

目的探讨蛋白酶抑制剂H89对神经元细胞经氧糖剥夺再灌注损伤后高尔基体形态和细胞凋亡的影响。方法将体外常规培养的小鼠海马神经元细胞HT22分为对照组、模型组和H89干预组。模型组与H89干预组按再灌注时间点分6h、12h和24h三个亚组。采用MTT法检测细胞存活率;Hoechest33258荧光染色法评估细胞凋亡;细胞免疫荧光技术观察高尔基体形态;Western blot技术检测GM130与GAAP蛋白表达。结果 H89干预组较模型组细胞活力有所上升,其中12h时间点(OD值0.1467±0.0090)与同期模型组比较,差异有统计学意义(P<0.05)。H89干预组较模型组细胞凋亡率有所下降,但差异均无统计学意义(P>0.05)。H89干预组在6h和12h时间点高尔基体碎裂程度较同期模型组稍有减轻。H89干预组GM130表达水平较模型组无显著升高(P>0.05)。GAAP表达水平仅在24h时间点(灰度比值0.4066±0.0288)显著升高(P<0.05)。结论 H89干预不能减轻神经元细胞经氧糖剥夺再灌注损伤后的高尔基体碎裂和细胞凋亡。

Mu-Xiang-You-Fang protects PC12 cells against OGD/R-induced autophagy via AMPK/mTOR signaling pathway

OBJECTIVE Mu-Xiang-You-Fang(MXYF)is a classic prescription of Hui medicine,composed of five herbs,which has been used to treat ischemic stroke for many years.However,the potential pharmacological mecha⁃nisms of MXYF remain unclear.The present research is to investigate the neuroprotective effect of MXYF and its role in modulating autophagy via AMPK/mTOR signaling pathway in the PC12 oxygen-glucose deprivation and reperfusion(OGD/R)injury model.METHODS MXYF was extracted by supercritical CO2 fluid extraction apparatus.PC12 OGD/R injury model was established by oxygen-glucose deprivation for 2 h and reperfusion for 24 h.The effects of MXYF on the viability and cytotoxicity of PC12 cells were determined through cell counting kit(CCK-8)assay.Colorimetric method was performed to determine the LDH leakage rate.The calcium concentration was determined by chemical fluorescence method and the mitochondrial membrane potential was determined through flow cytometry.Monodansylcadaverine(MDC)staining was conducted to detect autophagosome formation.The expression of LC3,Beclin1,p62,p-AMPK,ULK1,p-mTOR and p-p70s6k proteins were determined by immunofluorescence and Western blotting analyses.RESULTS MXYF(1,2 and 4 mg·L^-1)could significantly increase the cell viability and mitochondrial membrane potential,while decreased the release of lactate dehydrogenase(LDH)and calcium concentration in PC12 cells.Mechanistic studies showed that MXYF reduced the LC3-II/LC3-I ratio and inhibited the expression of beclin1,p-AMPK and ULK1.In comparison,the expres⁃sion of p-mTOR,p-p70s6k and p62 were significantly enhanced.CONCLUSION MXYF inhibits autophagy after OGD/Rinduced PC12 cell injury through AMPK-mTOR pathway,thus MXYF might have therapeutic potential for treating the ischemic stroke.

Hydroxysafflor Yellow A Inhibits Pyroptosis and Protecting HUVECs from OGD/R via NLRP3/Caspase-1/GSDMD Pathway

Objective:To observe the protective effect and mechanism of hydroxyl safflower yellow A(HsYA)from myocardial ischemia-reperfusion injury on human umbilical vein endothelial cells(HUVECs).Methods:HUVECs were treated with oxygen-glucose deprivation reperfusion(OGD/R)to simulate the ischemia reperfusion model,and cell counting kit-8 was used to detect the protective effect of different concentrations(1.25-160μmol/L)of HSYA on HUVECs after OGD/R.HSYA 80μmol/L was used for follow-up experiments.The contents of inflammatory cytokines interleukin(IL)-18,IL-1β,monocyte chemotactic protein 1(MCP-1),tumor necrosis factorα(TNF-α)and IL-6 before and after administration were measured by enzyme-linked immunosorbent assay.The protein expressions of toll-like receptor,NOD-like receptor containing pyrin domain 3(NLRP3),gasdermin D(GSDMD)and GSDMD-N-terminal domain(GSDMD-N)before and after administration were detected by Western blot.NLRP3 inflammasome inhibitor cytokine release inhibitory drug 3 sodium salt(CRID3 sodium salt,also known as MCC950)and agonist were added,and the changes of NLRP3,cysteine-aspartic acid protease 1(Caspase-1),GSDMD and GSDMD-N protein expressions were detected by Western blot.Results:HSYA inhibited OGD/R-induced inflammation and significantly decreased the contents of inflammatory cytokines IL-18,IL-1β,MCP-1,TNF-αandIL-6(P<0.01or P<0.05).At the same time,by inhibiting NLRP3/Caspase-1/GSDMD pathway,HSYA can reduce the occurrence of pyroptosis after OGD/R and reduce the expression of NLRP3,Caspase-1,GSDMD and GSDMD-N proteins(P<0.01).Conclusions:The protective effect of HSYA on HUVECs after OGD/R is related to down-regulating the expression of NLRP3 inflammasome and inhibiting pyroptosis.

Blockade of HCN2 Channels Provides Neuroprotection Against Ischemic Injury via Accelerating Autophagic Degradation in Hippocampal Neurons

In the central nervous system,hyperpolarizationactivated cyclic nucleotide-gated(HCN)channels are essential to maintain normal neuronal function.Recent studies have shown that HCN channels may be involved in the pathological process of ischemic brain injury,but the mechanisms remain unclear.Autophagy is activated in cerebral ischemia,but its role in cell death/survival remains controversial.In this study,our results showed that the HCN channel blocker ZD7288 remarkably decreased the percentage of apoptotic neurons and corrected the excessive autophagy induced by oxygen-glucose deprivation followed by reperfusion(OGD/R)in hippocampal HT22 neurons.Furthermore,in the OGD/R group,p-mTOR,p-ULK1(Ser757),and p62 were significantly decreased,while p-ULK1(Ser317),atg5,and beclin1 were remarkably increased.ZD7288 did not change the expression of p-ULK1(Ser757),ULK1(Ser317),p62,Beclin1,and atg5,which are involved in regulating autophagosome formation.Besides,we found that OGD/R induced a significant increase in Cathepsin D expression,but not LAMP-1.Treatment with ZD7288 at 10μmol/L in the OGD/R group did not change the expression of cathepsin D and LAMP-1.However,chloroquine(CQ),which decreases autophagosome-lysosome fusion,eliminated the correction of excessive autophagy and neuroprotection by ZD7288.Besides,shRNA knockdown of HCN2 channels significantly reduced the accumulation of LC3-Ⅱand increased neuron survival in the OGD/R and transient global cerebral ischemia(TGCI)models,and CQ also eliminated the effects of HCN2-shRNA.Furthermore,we found that the percentage of LC3-positive puncta that co-localized with LAMP-1-positive lysosomes decreased in Con-shRNAtransfected HT22 neurons exposed to OGD/R or CQ.In HCN2-shRNA-transfected HT22 neurons,the percentage of LC3-positive puncta that co-localized with LAMP-1-positive lysosomes increased under OGD/R;however,the percentage was significantly decreased by the addition of CQ to HCN2-shRNA-transfected HT22 neurons.The present results demonstrated that blockade of HCN2 channels provides neuroprotection against OGD/R and TGCI by accelerating autophagic degradation attributable to the promotion of autophagosome and lysosome fusion.