LncRNA SNHG12 regulated by WTAP aggravated the oxygen-glucose deprivation/reperfusion-induced injury in bEnd.3 cell.

OBJECTIVES: Previous studies have identified abnormal expression of lncRNA SNHG12 in ischemic stroke, but the underlying molecular mechanism remains unclear. MATERIALS AND METHODS: Through database predictions, m6A methylation sites were found on SNHG12, suggesting post-transcriptional modification. To further elucidate the role of SNHG12 and m6A methyltransferase WTAP in oxygen-glucose deprivation/reperfusion (OGD/R)-induced damage in cerebral microvascular endothelial cells, we conducted investigations. Additionally, we examined the impact of m6A methyltransferase WTAP on SNHG12 expression. RESULTS: Overexpressing SNHG12 in bEnd.3 cells was found to inhibit cell proliferation and promote apoptosis, as well as activate the production of reactive oxygen species and inflammatory cytokines (E-selectin, IL-6 and MCP-1), along with angiogenic proteins (VEGFA and FGFb). Conversely, SNHG12 knockdown alleviated OGD/R-induced damage to BEnd.3 cells, resulting in improved cell proliferation, reduced apoptosis, decreased ROS and LDH production, as well as diminished expression of inflammatory cytokines (E-selectin, IL-6 and MCP-1) and angiogenic proteins (VEGFA and FGFb). Furthermore, WTAP was found to positively regulate SNHG12 expression, and WTAP knockdown in bEnd.3 cells under the OGD/R conditions inhibited cell proliferation, promoted apoptosis, and increased ROS and LDH production. CONCLUSION: These findings suggest that WTAP may play a crucial role in SNHG12-mediated OGD/R-induced damage in bEnd.3 cells. More molecular experiments are needed to further analyze its mechanism. Overall, our study helps to enrich our understanding of the dysregulation of SNHG12 in ischemic stroke.

[Molecular mechanism of ligustilide attenuating OGD/R injury in PC12 cells by inhibiting ferroptosis].

The aim of this study is to explore the mechanism of ligustilide, the main active constituent of essential oils of traditional Chinese medicine Angelicae Sinensis Radix, on alleviating oxygen-glucose deprivation/reperfusion(OGD/R) injury in PC12 cells from the perspective of ferroptosis. OGD/R was induced in vitro, and 12 h after ligustilide addition during reperfusion, cell viability was detected by cell counting kit-8(CCK-8) assay. DCFH-DA staining was used to detect the level of intracellular reactive oxygen species(ROS). Western blot was employed to detect the expression of ferroptosis-related proteins, glutathione peroxidase 4(GPX4), transferrin receptor 1(TFR1), and solute carrier family 7 member 11(SLC7A11), and ferritinophagy-related proteins, nuclear receptor coactivator 4(NCOA4), ferritin heavy chain 1(FTH1), and microtubule-associated protein 1 light chain 3(LC3). The fluorescence intensity of LC3 protein was analyzed by immunofluorescence staining. The content of glutathione(GSH), malondialdehyde(MDA), and Fe was detected by chemiluminescent immunoassay. The effect of ligustilide on ferroptosis was observed by overexpression of NCOA4 gene. The results showed that ligustilide increased the viability of PC12 cells damaged by OGD/R, inhibited the release of ROS, reduced the content of Fe and MDA and the expression of TFR1, NCOA4, and LC3, and improved the content of GSH and the expression of GPX4, SLC7A11, and FTH1 compared with OGD/R group. After overexpression of the key protein NCOA4 in ferritinophagy, the inhibitory effect of ligustilide on ferroptosis was partially reversed, indicating that ligustilide may alleviate OGD/R injury of PC12 cells by blocking ferritinophagy and then inhibiting ferroptosis. The mechanism by which ligustilide reduced OGD/R injury in PC12 cells is that it suppressed the ferroptosis involved in ferritinophagy.

Molecular mechanism of ligustilide attenuating OGD/R injury in PC12 cells by inhibiting ferroptosis / 中国中药杂志

The aim of this study is to explore the mechanism of ligustilide, the main active constituent of essential oils of traditional Chinese medicine Angelicae Sinensis Radix, on alleviating oxygen-glucose deprivation/reperfusion(OGD/R) injury in PC12 cells from the perspective of ferroptosis. OGD/R was induced in vitro, and 12 h after ligustilide addition during reperfusion, cell viability was detected by cell counting kit-8(CCK-8) assay. DCFH-DA staining was used to detect the level of intracellular reactive oxygen species(ROS). Western blot was employed to detect the expression of ferroptosis-related proteins, glutathione peroxidase 4(GPX4), transferrin receptor 1(TFR1), and solute carrier family 7 member 11(SLC7A11), and ferritinophagy-related proteins, nuclear receptor coactivator 4(NCOA4), ferritin heavy chain 1(FTH1), and microtubule-associated protein 1 light chain 3(LC3). The fluorescence intensity of LC3 protein was analyzed by immunofluorescence staining. The content of glutathione(GSH), malondialdehyde(MDA), and Fe was detected by chemiluminescent immunoassay. The effect of ligustilide on ferroptosis was observed by overexpression of NCOA4 gene. The results showed that ligustilide increased the viability of PC12 cells damaged by OGD/R, inhibited the release of ROS, reduced the content of Fe and MDA and the expression of TFR1, NCOA4, and LC3, and improved the content of GSH and the expression of GPX4, SLC7A11, and FTH1 compared with OGD/R group. After overexpression of the key protein NCOA4 in ferritinophagy, the inhibitory effect of ligustilide on ferroptosis was partially reversed, indicating that ligustilide may alleviate OGD/R injury of PC12 cells by blocking ferritinophagy and then inhibiting ferroptosis. The mechanism by which ligustilide reduced OGD/R injury in PC12 cells is that it suppressed the ferroptosis involved in ferritinophagy.

Senkyunolide H protects PC12 cells from OGD/R-induced injury via cAMP-PI3K/AKT signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Senkyunolide H (SNH) is a bioactive phthalide isolated from Ligusticum chuanxiong Hort rhizome and was reported to have multiple pharmacological effects. AIM OF THE STUDY: The study was performed to verify the potency of SNH protecting PC12 cells from oxygen glucose deprivation/reperfusion (OGD/R)-induced injury and to elucidate the underlying mechanisms. MATERIALS AND METHODS: OGD/R model was established in PC12 cells and the cell viability was measured by MTT assay. The cell morphology was observed using scanning electron microscope (SEM). The potential targets of SNH and related targets of OGD/R were screened, and a merged protein-protein interaction (PPI) network of SNH and OGD/R was constructed based on the network pharmacology analysis. Kyoto Encyclopedia of Genes and Genomes (KEGG) database was used for pathway analysis. Intracellular cAMP level and the protein expression levels were measured to elucidate the underlying mechanisms. RESULTS: SNH pretreatment protected PC12 cells against OGD/R-induced cell death. SNH also significantly protected the cell protrusion. A merged PPI network was constructed and the shared candidate targets significantly enriched in cAMP signaling pathway. The level of intracellular cAMP and the protein level of p-CREB, p-AKT, p-PDK1 and PKA protein were up-regulated after the treatment of SNH compared with OGD/R modeling. CONCLUSIONS: The present study indicated that SNH protected PC12 cells from OGD/R-induced injury via cAMP-PI3K/AKT signaling pathway.

Detection of autophagic flux in primary cerebral cortical neurons after oxygen glucose deprivation/reperfusion (OGD/R) using various methods.

The current research hot spot in the field of autophagic flux is to explain and alleviate disease from the perspective of autophagy. A highly sophisticated, sensitive, quantifiable and comprehensive method is required to accurately determine the dynamic process of autophagic flux. There are very few methods in neuroscience that specifically examine autophagic flux. Therefore, primary cortical neurons were divided into oxygen glucose deprivation/reperfusion (OGD/R) (group A) and OGD/R plus bafilomycin A1 (BafA1) (group B) groups. ① Transfection of the LC3 gene with the RFP-GFP tandem fluorescent label was performed. ② Direct quantification was performed using transmission electron microscopy (TEM). ③ Autophagy-related tools were used to detect the transformation of LC3I/II. ④ SQSTM1/P62 combined with the LC3 protein flip test was performed to comprehensively evaluate autophagic flux. Using method one, the ratio of autophagolysosomes to autophagosomes in group A was significantly increased based on fluorescence microscopy analysis. Using method two, the autophagy process in group A was more continuous and unobstructed based on TEM analysis, while only some partial processes were observed in group B, and the number of autophagosomes and autophagy lysosomes in group A was significantly greater more than that in group B. The LC3II/I ratio measured in method three was analysed in detail to explain the autophagic flux. The ratio of soluble p62 combined with the ratio of LC3II/I detected using method four reflected the activation of autophagy. In summary, each method has its own advantages, and different methods and indicators can be used to monitor different stages of autophagy. An understanding of these advantages and mastery of these methods, is a very promising strategy to systematically and objectively study central nervous system diseases, facilitate the rational use of drugs, and formulate effective treatment plans from the perspective of autophagy.

Oxidative Stress Underlies the Ischemia/Reperfusion-Induced Internalization and Degradation of AMPA Receptors.

Stroke is the fifth leading cause of death annually in the United States. Ischemic stroke occurs when a blood vessel supplying the brain is occluded. The hippocampus is particularly susceptible to AMPA receptor-mediated delayed neuronal death as a result of ischemic/reperfusion injury. AMPA receptors composed of a GluA2 subunit are impermeable to calcium due to a post-transcriptional modification in the channel pore of the GluA2 subunit. GluA2 undergoes internalization and is subsequently degraded following ischemia/reperfusion. The subsequent increase in the expression of GluA2-lacking, Ca2+-permeable AMPARs results in excitotoxicity and eventually delayed neuronal death. Following ischemia/reperfusion, there is increased production of superoxide radicals. This study describes how the internalization and degradation of GluA1 and GluA2 AMPAR subunits following ischemia/reperfusion is mediated through an oxidative stress signaling cascade. U251-MG cells were transiently transfected with fluorescently tagged GluA1 and GluA2, and different Rab proteins to observe AMPAR endocytic trafficking following oxygen glucose-deprivation/reperfusion (OGD/R), an in vitro model for ischemia/reperfusion. Pretreatment with Mn(III)tetrakis(1-methyl-4-pyridyl)porphyrin (MnTMPyP), a superoxide dismutase mimetic, ameliorated the OGD/R-induced, but not agonist-induced, internalization and degradation of GluA1 and GluA2 AMPAR subunits. Specifically, MnTMPyP prevented the increased colocalization of GluA1 and GluA2 with Rab5, an early endosomal marker, and with Rab7, a late endosomal marker, but did not affect the colocalization of GluA1 with Rab11, a marker for recycling endosomes. These data indicate that oxidative stress may play a vital role in AMPAR-mediated cell death following ischemic/reperfusion injury.

Trigonelline protects hippocampal neurons from oxygen-glucose deprivation-induced injury through activating the PI3K/Akt pathway.

Trigonelline is a plant alkaloid that has generated interest for its neuroprotective roles in brain pathology. However, the protective effect of trigonelline on cerebral ischemia/reperfusion (I/R) injury and the potential mechanism have not been fully evaluated. Our results showed that trigonelline pretreatment ameliorated oxygen-glucose deprivation/reperfusion (OGD/R)-induced hippocampal neurons injury. The OGD/R-caused reactive oxygen species (ROS) generation and decreased concentrations of superoxide dismutases (SOD) and glutathione peroxidase (GPx) were markedly attenuated by trigonelline. In addition, the increased levels of TNF-α, IL-6 and IL-1ß in OGD/R-induced hippocampal neurons were significantly decreased by trigonelline pretreatment. Trigonelline also suppressed caspase-3 activity and bax expression, and induced bcl-2 expression in OGD/R-induced hippocampal neurons. Furthermore, trigonelline induced the activation of PI3K/Akt pathway in hippocampal neurons exposed to OGD/R condition. Inhibition of PI3K/Akt signaling reversed the protective effects of trigonelline on OGD/R-induced hippocampal neurons injury. Taken together, these findings indicated that trigonelline protected hippocampal neurons from OGD/R-induced injury, which was mediated by the activation of PI3K/Akt signaling pathway.

Knockdown of TRIM32 Protects Hippocampal Neurons from Oxygen-Glucose Deprivation-Induced Injury.

Tripartite motif 32 (TRIM32) is a member of TRIM family that plays a potential role in neural regeneration. However, the biological function of TRIM32 in cerebral ischemia reperfusion injury has not been investigated. In the present study, we evaluated the expression level of TRIM32 in hippocampal neurons following oxygen-glucose deprivation/reperfusion (OGD/R). The results showed that TRIM32 expression was significantly elevated in hippocampal neurons subjected to OGD/R as compared to the neurons cultured in the normoxia condition. To further evaluate the role of TRIM32, hippocampal neurons were transfected with TRIM32 small interfering RNA (si-TRIM32) to knock down TRIM32. We found that knockdown of TRIM32 improved cell viability of OGD/R-stimulated hippocampal neurons. Generation of reactive oxygen species was decreased, while contents of superoxide dismutase and glutathione peroxidase were increased after si-TRIM32 transfection. Knockdown of TRIM32 suppressed cell apoptosis, as proved by the increased bcl-2 expression along with decreased bax expression and caspase-3 activity. We also found that TRIM32 knockdown enhanced OGD/R-induced activation of Nrf2 signaling pathway in hippocampal neurons. Furthermore, siRNA-Nrf2 was transfected to knock down Nrf2. SiRNA-Nrf2 transfection reversed the protective effects of TRIM32 knockdown on neurons. These data suggested that knockdown of TRIM32 protected hippocampal neurons from OGD/R-induced oxidative injury through activating Nrf2 signaling pathway.

[Neuroprotective effects and mechanism of ethanol extract of Cistanche tubulosa against oxygen-glucose deprivation/reperfusion].

To investigate the inhibitory effects and mechanism of Cistanche tubulosa ethanol extract( CTEE) against oxygen-glucose deprivation/reperfusion( OGD/R)-induced PC12 cells neuronal injury. In this study,OGD/R-induced PC12 cells were used to explore the neuroprotective effects of CTEE( 12. 5,25,50 mg·L-1) by detecting cell viability with MTT assay,apoptosis with AO/EB and Hoechst 33258,mitochondrial membrane potential changes with JC-1 staining,mitochondrial oxidative stress with MitoSOX staining,as well as the apoptosis-related protein expression( PARP,cleaved PARP,caspase-3,cleaved caspase-3,Bax,Bcl-2) with Western blot. RESULTS:: showed that CTEE effectively protected OGD/R-induced neuronal injury and increased the survival rate of PC12 cells.AO/EB and Hoechst 33258 staining showed that CTEE could effectively inhibit apoptosis. Moreover,JC-1 and MitoSOX staining results showed that CTEE decreased mitochondrial stress and mitochondrial membrane potential imbalance in PC12 cells in a concentration-dependent manner. Meanwhile,CTEE could obviously suppress the activation of key proteins in mitochondrial apoptosis pathway such as caspase-3 and PARP,and significantly inhibit the rise of Bax and down-regulation of Bcl-2. In conclusion,CTEE has obvious protective effects on OGD/R-induced PC12 cells neuronal injury,potentially via inhibiting mitochondrial oxidative stress and apoptosis-related signaling pathway.

The dual role of KCNQ/M channels upon OGD or OGD/R insults in cultured cortical neurons of mice: Timing is crucial in targeting M-channels against ischemic injur ies.

KCNQ/M potassium channels play a vital role in neuronal excitability; however, it is required to explore their pharmacological modulation on N-Methyl- d-aspartic acid receptors (NMDARs)-mediated glutamatergic transmission of neurons upon ischemic insults. In the current study, both presynaptic glutamatergic release and activities of NMDARs were measured by NMDAR-induced miniature excitatory postsynaptic currents (mEPSCs) in cultured cortical neurons of C57 mice undergoing oxygen and glucose deprivation (OGD) or OGD/reperfusion (OGD/R). The KCNQ/M-channel opener, retigabine (RTG), suppressed the overactivation of postsynaptic NMDARs induced by OGD and then NO transient; RTG also decreased OGD-induced neuronal death measured with MTT assay, suggesting the beneficial role of KCNQ/M-channels for the neurons exposed to ischemic insults. However, when the neurons exposed to the subsequent reperfusion, KCNQ/M-channels played a differential role from its protective effect. OGD/R increased presynaptic glutamatergic release, which was further augmented by RTG or decreased by KCNQ/M-channel blocker, XE991. Reactive oxygen species (ROS) were produced partly in a NO-dependent manner. In addition, XE991 decreased neuronal injuries upon reperfusion measured with DCF and PI staining. Meanwhile, the addition of RTG upon OGD or XE991 upon reperfusion can reverse OGD or OGD/R-reduced mitochondrial membrane potential. Our present study indicates the dual role of KCNQ/M-channels in OGD and OGD/R, which will decide the fate of neurons. Provided that activation of KCNQ/M-channels has differential effects on neuronal injuries during OGD or OGD/R, we propose that therapy targeting KCNQ/M-channels may be effective for ischemic injuries but the proper timing is so crucial for the corresponding treatment.

Neuroprotective effects and mechanism of ethanol extract of Cistanche tubulosa against oxygen-glucose deprivation/reperfusion / 中国中药杂志

To investigate the inhibitory effects and mechanism of Cistanche tubulosa ethanol extract( CTEE) against oxygen-glucose deprivation/reperfusion( OGD/R)-induced PC12 cells neuronal injury. In this study,OGD/R-induced PC12 cells were used to explore the neuroprotective effects of CTEE( 12. 5,25,50 mg·L-1) by detecting cell viability with MTT assay,apoptosis with AO/EB and Hoechst 33258,mitochondrial membrane potential changes with JC-1 staining,mitochondrial oxidative stress with MitoSOX staining,as well as the apoptosis-related protein expression( PARP,cleaved PARP,caspase-3,cleaved caspase-3,Bax,Bcl-2) with Western blot. RESULTS:: showed that CTEE effectively protected OGD/R-induced neuronal injury and increased the survival rate of PC12 cells.AO/EB and Hoechst 33258 staining showed that CTEE could effectively inhibit apoptosis. Moreover,JC-1 and MitoSOX staining results showed that CTEE decreased mitochondrial stress and mitochondrial membrane potential imbalance in PC12 cells in a concentration-dependent manner. Meanwhile,CTEE could obviously suppress the activation of key proteins in mitochondrial apoptosis pathway such as caspase-3 and PARP,and significantly inhibit the rise of Bax and down-regulation of Bcl-2. In conclusion,CTEE has obvious protective effects on OGD/R-induced PC12 cells neuronal injury,potentially via inhibiting mitochondrial oxidative stress and apoptosis-related signaling pathway.

Madecassoside protects BV2 microglial cells from oxygen-glucose deprivation/reperfusion-induced injury via inhibition of the toll-like receptor 4 signaling pathway.

In a previous study, the authors reported that madecassoside (MA) exerted a potent neuroprotective effect against cerebral ischemia-reperfusion (I/R) injury in rats, mediated by anti-oxidative, anti-inflammatory, and anti-apoptotic mechanisms. However, the cellular and molecular bases for its neuroprotective effects have not been fully elucidated. In this study, an in vitro ischemic model of oxygen-glucose deprivation followed by reperfusion (OGD/R) was used to investigate the role of the toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88)/nuclear factor-kappa B (NF-κB) pathway in the neuroprotective and anti-inflammatory effects of MA. BV2 microglia viability after OGD/R, treated with or without MA, was measured using the MTT assay. Messenger RNA and protein expression of pro-inflammatory cytokines (tumor necrosis factor α [TNF-α], interleukin-1ß [IL-1ß], interleukin-6 [IL-6]) were measured using real-time polymerase chain reaction (RT-PCR) and ELISA after OGD/R or lipopolysaccharide treatment. Expression of TLR4/MyD88 and NF-κB p65 were measured using RT-PCR, Western blotting, and immunofluorescence analysis. MA significantly rescued OGD/R-induced cytotoxicity in BV2 microglia. Meanwhile, MA suppressed the secretion of pro-inflammatory mediators, including TNF-α, IL-1ß, and IL-6, induced by OGD/R or lipopolysaccharide in BV2 microglia. The mechanism of its neuroprotection and anti-inflammation from OGD/R may involve the inhibition of activation of TLR4 and MyD88 in BV2 microglia, and the blockage of NF-κB p65 nuclear translocation. MA exhibited a significant neuroprotective effect against I/R injury in both in vivo and in vitro experiments by attenuating microglia-mediated neuroinflammation via inhibition of the TLR4/MyD88/NF-κB signaling pathway.

Lycium barbarum polysaccharide protects against oxygen glucose deprivation/reoxygenation-induced apoptosis and autophagic cell death via the PI3K/Akt/mTOR signaling pathway in primary cultured hippocampal neurons.

Lycium barbarum polysaccharide (LBP) is the main active ingredient of Lycium barbarum, which exhibits several beneficial effects, including neuroprotection, anti-aging and anti-oxidation. However, the mechanism by which LBP protects against cerebral ischemia/reperfusion-induced injury remains obscure. In this study, we found that LBP pretreatment greatly attenuated oxygen glucose deprivation/reperfusion (OGD/R) injury in primary cultured hippocampal neurons. LBP also suppressed OGD/R-induced lactate dehydrogenase (LDH) leakage, and ameliorated oxidative stress. In addition, LBP significantly reduced OGD/R-induced apoptosis and autophagic cell death. LBP caused the down-regulation of cleaved Caspase-3/Caspase-3, LC3II/LC3I and Beclin 1, as well as up-regulation of Bcl-2/Bax and p62. Furthermore, mechanistic studies indicated that LBP pretreatment increased p-Akt and p-mTOR levels after OGD/R. In summary, our results indicated that LBP protects against OGD/R-induced neuronal injury in primary hippocampal neurons by activating the PI3K/Akt/mTOR signaling pathway.

Effect of oxygen glucose deprivation-reperfusion in astrocytes overexpressing endothelin-1 on the proliferation of neural stem/progenitor cells / 器官移植

Objective To investigate the effect of oxygen glucose deprivation-reperfusion (OGD-R) in astrocytes overexpressing endothelin (ET)-1 on the proliferation of neural stem/progenitor cells (NSPCs). Methods OGD-R models of negative control astrocytes (C6-Mock) and astrocytes over-expressing ET-1 (C6-ET-1) were constructed. Transwell co-culture system of astrocytes and NSPCs was established. Morphologic observation and identification of the astrocytes and primary NSPCs were performed. The cells were divided into four groups: C6-Mock+NSPCs, OGD-R+C6-Mock+NSPCs, C6-ET-1+NSPCs and OGD-R+C6-ET-1+NSPCs groups and co-cultured for 0, 24, 48 and 72 h respectively. The diameter of neurosphere was measured in each group. Results In the C6-Mock and C6-ET-1 cells, type Ⅰ astrocytes in fibrous morphology were observed. Glial fibrillary acidic protein (GFAP) was expressed in the cytoplasm of these two types of cells. Primary NSPCs were positive for nestin staining. After co-culture for 48 and 72 h, the neurosphere diameter in the OGD-R+C6-Mock+NSPCs group was significantly greater than that in the C6-Mock+NSPCs group. The neurosphere diameter in the OGD-R+C6-ET-1+NSPCs group was considerably greater than that in the C6-ET-1+NSPCs group. The neurosphere diameter in the OGD-R+C6-ET-1+NSPCs group was significantly greater compared with that in the OGD-R+C6-Mock+NSPCs group (all P<0.05). Conclusions OGD-R astrocytes can promote the proliferation of NSPCs. ET-1 over-expression further accelerates the proliferation of NSPCs.

The protective activity of imperatorin in cultured neural cells exposed to hypoxia re-oxygenation injury via anti-apoptosis.

Apoptosis is believed to play important roles in neuronal cell death associated with cerebral ischemia. We now provided evidence that imperatorin (IMp), the main composition of the dried root or rhizome of R Radix Angelicae Dahuricae, took advantage on oxygen glucose deprivated/reperfusion (OGD-R) SH-SY5Y cell line through neuronal apoptosis inhibition. Our data had shown that imperatorin reduced the number of apoptosis cells after OGD-R, this effect was associated with the inhibition of the apoptosis factors Bax and caspase-3, and the upregulation of anti-apoptosis factor Bcl-2. In the meantime, the protective factor BDNF was upregulated significantly by imperatorin treatment. In our experiment in vivo, imperatorin decreased the infract volume significantly in dose of 5 mg/kg and 10 mg/kg, and the behavior ability was increased in the 10mg/kg of imperatorin. Our observations show that imperatorin exerted protective effect on cerebral ischemia both in vitro and in vivo, this effect is associated with its anti-apoptosis function.