Oxygen-glucose Deprivation Group Research Articles

Single-nucleus transcriptome unveils the role of ferroptosis in ischemic stroke

Multiple cell death pathways are involved in neuronal death in ischemic stroke (IS). However, the role of different cell death pathways in different cell types has not been elucidated. By analyzing three single-nucleus RNA sequencing (snRNA-seq) data of IS, we first found that a variety of programmed cell death (PCD) -related genes were significantly changed in different cell types. Based on machine learning and virtual gene knockout, we found that ferroptosis related genes, ferritin heavy chain 1 (Fth1) and ferritin light chain (Ftl1), play a key role in IS. Ftl1 and Fth1 can promote microglia activation, as well as the production of inflammatory factors and chemokines. Cell communication analysis showed that activated microglia could enhance chemotactic peripheral leukocyte infiltration, such as macrophages and neutrophils, through Spp1-Cd44 and App-Cd74 signaling, thereby aggravating brain tissue damage. Furthermore, real‐time quantitative polymerase chain reaction (RT‐qPCR) showed that P2ry12 and Mef2c were significantly decreased in oxygen-glucose deprivation (OGD) group, while Ftl1, Fth1, Apoe, Ctsb, Cd44 and Cd74 were significantly increased in OGD group. Collectively, our findings suggested targeted therapy against microglia Ftl1 and Fth1 might improve the state of microglia, reduce the infiltration of peripheral immune cells and tissue inflammation, and then improve the ischemic brain injury in mouse.

Salvianic acid A sodium facilitates cardiac microvascular endothelial cell proliferation by enhancing the hypoxia-inducible factor-1 alpha/vascular endothelial growth factor signalling pathway post-myocardial infarction.

Cardiac microvascular endothelial cells (CMECs) are important cells surrounding the cardiomyocytes in the heart that maintain microenvironment homeostasis. Salvianic acid A sodium (SAAS) has been reported to prevent myocardial infarction (MI) injury. However, the role of SAAS on CMEC proliferation remains unclear. CEMCs exposed to oxygen glucose deprivation (OGD) were used to explore the angiogenic abilities of SAAS. In vivo, C57BL/6 mice were divided into three groups: sham, MI and SAAS + MI groups. Compared to OGD group, SAAS led to a reduction in the apoptotic rate and an increase of the proliferation in vitro. Additionally, SAAS increased the protein levels of Bcl2, HIF-1α and vascular endothelial growth factor (VEGF) with the reduction of Bax. In terms of the specific mechanisms, SAAS might inhibit HIF-1α ubiquitination and enhance the HIF-1α/VEGF signalling pathway to increase CMEC proliferation. Furthermore, SAAS increased the density of vessels, inhibited myocardial fibrosis and improved cardiac dysfunction in vivo. The present study has revealed that SAAS could potentially be used as an active substance to facilitate CMEC proliferation post-MI.

CGAS Deficiency Regulates the Phenotypic Polarization and Glycolysis of Microglia Through Lactylation in Hypoxic-Ischemic Encephalopathy Cell Model.

Promoting the M2 phenotype polarization of microglia is of great significance in alleviating hypoxic-ischemic encephalopathy (HIE). The umbilical artery blood sample was collected to evaluate the expression of cGAS, and the aberrant expressed cGAS was verified in the oxygen glucose deprivation (OGD) microglia which was established to mimic HIE in vitro. Then the regulating role of cGAS on the transformation of microglia M2 phenotype polarization and glycolysis was investigated. Moreover, the lactylation of cGAS in OGD treated microglia was evaluated by western blot. cGAS was found to be highly expressed in umbilical artery blood of HIE group, and OGD treated microglia. OGD interference activated microglia into M1 phenotype by enhancing CD86 and suppressing CD206 levels; meanwhile, the microglia in OGD group highly expressed IL-1β, iNOS and TNF-α, and lowly expressed IL-4, IL-10, and Arg-1. Inhibition of cGAS promotes the transformation of microglia from M1 to M2 phenotype. Meanwhile, OGD increased ECAR and decreased OCR to regulate glycolysis, cGAS deficiency inhibits glycolysis in OGD treated microglia. Moreover, the pan lysine lactylation (Pan-Kla) levels and lactated cGAS levels in microglia were upregulated in the OGD group. Lactate reversed the effects of cGAS knockdown on microglia polarization and glycolysis. The present study reveals that the cGAS-mediated neuron injury is associated with high level of cGAS lactylation. Inhibition of cGAS promotes the M2 phenotype polarization of microglia and suppress glycolysis. Thereby, targeting cGAS provides a new strategy for the development of therapeutic agents against HIE.

Integrated transcriptomic and proteomic profiling reveals the key molecular signatures of brain endothelial reperfusion injury.

Reperfusion therapy after ischemic stroke often causes brain microvascular injury. However, the underlying mechanisms are unclear. Transcriptomic and proteomic analyses were performed on human cerebral microvascular endothelial cells following oxygen-glucose deprivation (OGD) or OGD plus recovery (OGD/R) to identify molecules and signaling pathways dysregulated by reperfusion. Major findings were further validated in a mouse model of cerebral ischemia and reperfusion. Transcriptomic analysis identified 390 differentially expressed genes (DEGs) between the OGD/R and OGD group. Pathway analysis indicated that these genes were mostly associated with inflammation, including the TNF signaling pathway, TGF-β signaling pathway, cytokine-cytokine receptor interaction, NOD-like receptor signaling pathway, and NF-κB signaling pathway. Proteomic analysis identified 201 differentially expressed proteins (DEPs), which were primarily associated with extracellular matrix destruction and remodeling, impairment of endothelial transport function, and inflammatory responses. Six genes (DUSP1, JUNB, NFKBIA, NR4A1, SERPINE1, and THBS1) were upregulated by OGD/R at both the mRNA and protein levels. In mice with cerebral ischemia and reperfusion, brain TNF signaling pathway was activated by reperfusion, and inhibiting TNF-α with adalimumab significantly attenuated reperfusion-induced brain endothelial inflammation. In addition, the protein level of THBS1 was substantially upregulated upon reperfusion in brain endothelial cells and the peri-endothelial area in mice receiving cerebral ischemia. Our study reveals the key molecular signatures of brain endothelial reperfusion injury and provides potential therapeutic targets for the treatment of brain microvascular injury after reperfusion therapy in ischemic stroke.

Hydrogen‑rich saline promotes neuronal recovery in mice with cerebral ischemia through the AMPK/mTOR signal‑mediated autophagy pathway.

This study explored the protective effect and mechanism of hydrogen‑rich saline (HRS) on the neurological function of mice with cerebral ischemia. Effects of HRS on neurological function in mice with cerebral ischemia were evaluated by neurological function scores. Infarct volume and histological damage were evaluated by 2,3,5‑triphenyl tetrazolium chloride staining (TTC staining). Golgi‑Cox staining was conducted to measure the morphological changes of neuronal dendrites and dendritic spines. The expression of neuronal markers was detected by immunofluorescence. Western blot was used to detect protein expression. The infarct volume of mice in the HRS‑H group decreased significantly compared to that of the distal middle cerebral artery occlusion (dMCAO) group. Mice in the HRS‑H group had a lower neurological deficit score than that in the dMCAO group. Compared to the dMCAO group, the activity of superoxide dismutase (SOD) and the level of glutathione (GSH) significantly increased in the HRS‑H group. Compared with the dMCAO group, the number of apoptotic cells in the HRS‑H group decreased. Administration of HRS was shown to be able to decrease cavitation of the brain cortex after ischemia. The spine density in the HRS‑H group increased compared to that of the dMCAO group. In the in vitro experiment, compared with the oxygen‑glucose deprivation (OGD) group, the active oxygen content in the 75% HRM group decreased, and the mitochondrial membrane potential and adenosine triphosphate (ATP) content increased. Compared with the OGD group, the ratio of P‑AMPK and the levels of LC3II/LC3I in the hydrogen‑rich medium (HRM) group was upregulated, and P‑mTOR levels and P62 levels in the HRM group were down‑regulated. HRS can enhance neuroplasticity after ischemia and promote neurological recovery in mice with cerebral ischemia, which may involve the autophagy pathway mediated by the AMPK/mTOR signaling pathway.

Mechanism for effect of tanshinone IIA on alleviating cardiomyocyte injury induced by oxygen glucose deprivation.

Tanshinone IIA has a wide range of myocardial protective effects. AK003290 is a long noncoding RNA (lncRNA) that is highly expressed in myocardial tissue, and its expression is down-regulated when myocardial injury occurs. This study aims to explore the mechanism for tanshinone IIA in alleviating myocardial cell damage induced by oxygen glucose deprivation (OGD). OGD model was established in rat H9C2 cardiomyocytes. siRNA was transfected to reduce AK003290 expression. H9C2 cells were divided into 6 groups: A control group, a tanshinone IIA (TAN) group, an OGD group, a tanshinone IIA+OGD (TAN+OGD) group, a scrambled siRNA transfection+tanshinone IIA+OGD (scrambled siRNA+TAN+OGD) group, and a AK003290 siRNA transfection+tanshinone IIA+OGD (AK003290 siRNA+TAN+OGD) group. H9C2 cells in the TAN group were treated with 40 μmol/L tanshinone IIA for 12 h. The TAN+OGD group was treated with 40 μmol/L tanshinone IIA for 12 h, followed by OGD treatment for 12 h. The scrambled siRNA+TAN+OGD group and AK003290 siRNA+TAN+OGD group were transfected with the scrambled siRNA or AK003290 siRNA. Twenty-four hours later, the cells were treated with tanshinone IIA and OGD. Real-time RT-PCR was used to detect the expression of AK003290. Spectrophotometry was used to detect the content of lactate dehydrogenase (LDH) in cell culture medium to reflect LDH leakage rate, and enzyme-linked immunosorbent assay (ELISA) was used to detect the content of interleukin-1β (IL-1β) and interleukin-18 (IL-18). Western blotting was used to detect the protein expression of phospho-nuclear factor- κB (p-NF-κB). Compared with the control group, the leakage rate of LDH, the content of IL-1β and IL-18 in culture medium, and the protein expression level of p-NF-κB were increased in the OGD group (P<0.01 or P<0.001). Compared with the OGD group, the leakage rate of LDH, the content of IL-1β and IL-18 in culture medium, and the protein expression level of p-NF-κB were decreased in the TAN+OGD group (P<0.05 or P<0.01). Compared with the control group, the AK003290 expression was increased in the TAN group (P<0.01) and it was decreased in the OGD group (P<0.05). Compared with the OGD group, the AK003290 expression was increased in the TAN+OGD group (P<0.05). Compared with the scrambled siRNA+TAN+OGD group, the leakage rate of LDH, the content of IL-1β and IL-18 in culture medium, and the protein expression level of p-NF-κB were increased in the AK003290 siRNA+TAN+OGD group (P<0.05 or P<0.01). Tanshinone IIA inhibits NF-κB activity and attenuates OGD-induced inflammatory injury of cardiomyocytes through up-regulating AK003290.

MCC950 Regulates Stem Cells Destiny Through Modulating SIRT3-NLRP3 Inflammasome Dynamics During Oxygen Glucose Deprivation.

Ischemic stroke is the major cause of death and morbidity worldwide. Stem cell treatment is at the forefront of ischemic therapeutic interventions. However, the fate of these cells following transplantation is mostly unknown. The current study examines the influence of oxidative and inflammatory pathological events associated with experimental ischemic stroke (oxygen glucose deprivation (OGD)) on the stem cell population (human Dental Pulp Stem Cells, and human Mesenchymal Stem Cells) through the involvement of the NLRP3 inflammasome. We explored the destiny of the above-mentioned stem cells in the stressed micro (-environment) and the ability of MCC950 to reverse the magnitudes. An enhanced expression of NLRP3, ASC, cleaved caspase1, active IL-1β and active IL-18 in OGD-treated DPSC and MSC was observed. The MCC950 significantly reduced NLRP3 inflammasome activation in the aforementioned cells. Further, in OGD groups, oxidative stress markers were shown to be alleviated in the stem cells under stress, which was effectively relieved by MCC950 supplementation. Interestingly, whereas OGD increased NLRP3 expression, it decreased SIRT3 levels, implying that these two processes are intertwined. In brief, we discovered that MCC950 inhibits NLRP3-mediated inflammation by inhibiting the NLRP3 inflammasome and increasing SIRT3. To conclude, according to our findings, inhibiting NLRP3 activation while enhancing SIRT3 levels with MCC950 reduces oxidative and inflammatory stress in stem cells under OGD-induced stress. These findings shed light on the causes of hDPSC and hMSC demise following transplantation and point to strategies to lessen therapeutic cell loss under ischemic-reperfusion stress.

Neuroprotective effect of a novel brain-derived peptide, HIBDAP, against oxygen-glucose deprivation through inhibition of apoptosis in PC12 cells.

The effect of a novel brain-derived peptide,hypoxic-ischemic brain damage associated peptide (HIBDAP), on apoptosis after oxygen-glucose deprivation (OGD) in PC12 cells was investigated. The HIBDAP sequence (HSQFIGYPITLFVEKER) was coupled with the carrier peptide of the transactivator of transcription (TAT) sequence (YGRKKRRQRRR). FITC-labelled TAT-HIBDAP was observed by fluorescence microscopy. After TAT-HIBDAP treatment and OGD treatment, the PC12 cell apoptosis rate was analysed using lactate dehydrogenase (LDH) leakage and Annexin V-fluorescein isothiocyanate (FITC) assays. Mitochondrial membrane potential (ΔΨm) was examined by fluorescence microscopy. Protein expression of apoptotic factors was examined by Western blotting. FITC-labelled TAT-HIBDAP entered the PC12 cell nucleus. Compared with the OGD group, TAT-HIBDAP at low concentrations (1 µM, 5 µM, 10 µM) significantly reduced the apoptosis rate of PC12 cells (except at 20 µM); 5 µM TAT-HIBDAP had the most obvious effect. There were remarkable increases in ΔΨm at different concentrations (1 µM, 5 µM, 10 µM, 20 µM) of TAT-HIBDAP pretreatment, and 5 µM TAT-HIBDAP also had the most obvious effect. TAT-HIBDAP reversed the increased ratio of Bax/Bcl-2 and activation of Caspase-3 induced by OGD. TAT-HIBDAP is resistant to OGD-induced PC12 cell apoptosis by regulating the Bax/Bcl-2/Caspase-3 pathway, which may provide a novel therapeutic strategy for neonatal HIBD.

Advanced Glycation End-Products (AGEs) Promote Endothelial Cell Pyroptosis Under Cerebral Ischemia and Hypoxia via HIF-1α-RAGE-NLRP3.

This work mainly aimed to explore the role and mechanism of advanced glycation end-products (AGEs) in inducing cerebrovascular endothelial cell pyroptosis under oxygen glucose deprivation (OGD) condition. The mouse cerebral microvascular endothelial cells (BMECs and bEnd.3) were used as the objects to construct the OGD model in vitro. Then, cells were pretreated with AGE-modified human serum albumin (AGE-HSA). Thereafter, CCK-8 assay was conducted to detect cell viability, and flow cytometry (FCM) was performed to measure cell pyroptosis level. Meanwhile, the expression of inflammatory factors was detected by enzyme-linked immunosorbent assay (ELISA). The expression of HIF-α, NLRP3, and RAGE was detected by fluorescence staining. The opening status of cell membrane pore was observed under the electron microscope, and the expression levels of FL-GSDMD, NT-GSDMD, and caspase-1 were measured through Western Blot (WB) assay. Moreover, bEnd.3 cells were treated with siRAN-silenced NLRP3 and HIF-α inhibitor, so as to observe the effect of AGEs on cell pyroptosis level. In the mouse model, the middle cerebral artery occlusion (MCAO) model was constructed by the suture-occluded method. After intraperitoneal injection of AGEs, the pathological changes in mouse brain tissues were detected; the expression levels of NLRP3, ZO-1, and CD31 were determined by histochemical staining, and the levels of inflammatory factors and pyroptosis-related proteins were also detected. Under OGD condition, AGEs induced the pyroptosis of bEnd.3 cells, and the cell pyroptosis rate increased, higher than that of the OGD group. Meanwhile, the levels of inflammatory factors were up-regulated; the expression of HIF-α, NLRP3, and RAGE in cells increased; and the levels of NT-GSDMD and caspase-1 were markedly higher than those of the control and OGD groups. siRNA-NLRP3 or HIF-α inhibitor treatment suppressed pyroptosis and reduced the inflammatory factor levels. In mouse experiments, AGE injection aggravated brain injury in the MCAO mouse model, decreased the expression of ZO-1 and CD31, and elevated the levels of NLRP3 and inflammatory factors. Under cerebral ischemia condition, AGEs can induce endothelial cell pyroptosis via HIF-α-RAGE-NLRP3, thereby further aggravating brain injury.

MiR-200b-3p antagomir inhibits neuronal apoptosis in oxygen-glucose deprivation (OGD) model through regulating β-TrCP

BackgroundHypoxia-ischemic brain damage (HIBD) is a primary cause of morbidity and disability in survivors of preterm infants. We previously discovered that miR-200b-3p plays an important role in HIBD via targeting Slit2. This study was designed to identify novel targets of miR-200b-3p and investigate the relationship between miR-200b-3p and its downstream effectors. Methods and resultsCultured primary rat hippocampal neurons were used in the model of oxygen-glucose deprivation (OGD) and RT-qPCR was utilized to detect the alterations of miR-200b-3p in these cells following the OGD. Our study found that the expression of miR-200b-3p was up-regulated in neurons post OGD. Bioinformatics analysis identified that β transducin repeat-containing protein (β-TrCP) is a target gene of miR-200b-3p, and our luciferase reporter gene assay confirmed that miR-200b-3p can interact with β-TrCP mRNA. Hypoxia-ischemic brain damage was induced in three-day-old SD rats and inhibition of miR-200b-3p by injection of antagomir into bilateral lateral ventricles enhanced β-TrCP expression at both the mRNA and protein levels in rats' brains. TUNEL staining and CCK-8 assays found that the survival of hippocampal neurons in the miR-200b-3p antagomir group was improved significantly (p＜0.05), whereas apoptosis of neurons in the miR-200b-3p antagomir group was significantly decreased (p＜0.05), as compared with the OGD group. However, silencing of β-TrCP by β-TrCP siRNA impaired the neuroprotective effect of miR-200b-3p antagomir. H&E staining showed that miR-200b-3p attenuated the pathological changes in the hippocampal region of rats with HIBD. ConclusionOur study has demonstrated that β-TrCP is a target gene of miR-200b-3p and that inhibition of miR-200b-3p by antagomir attenuates hypoxia-ischemic brain damage via β-TrCP.

Apelin-13 Protects Neurons by Attenuating Early-Stage Postspinal Cord Injury Apoptosis In Vitro.

Apelin is a 77-amino-acid peptide that is an endogenous ligand for the G protein-coupled receptor APJ (Apelin receptor, APJ). Apelin-13, as the most bioactive affinity fragment of apelin, plays a role in energy metabolism, myocardial ischemia‒reperfusion injury, and the regulation of the inflammatory response during oxidative stress, but its role in spinal cord injury is still unclear. This research identified and verified the differential expression of apelin in rat spinal cord injured tissues and normal spinal cord tissues by transcriptome sequencing in vivo and proved that apelin-13 protects neurons by strengthening autophagy and attenuating early-stage postspinal cord injury apoptosis in vitro. After constructing the model concerning a rat spinal cord hemisection damage, transcriptome sequencing was performed on the injured and normal spinal cord tissues of rats, which identified the differentially expressed gene apelin, with qRT-PCR detecting the representative level of apelin. The oxygen-glucose deprivation (OGD) model of PC12 cells was constructed in vitro to simulate spinal cord injury. The OGD injury times were 2 h, 4 h, 6 h, 8 h, and 12 h, and the non-OGD injury group was used as the control. The expression of apelin at each time point was observed by Western blotting. The expression of apelin was the lowest in the 6 h OGD injury group (p &lt; 0.05). Therefore, the OGD injury time of 6 h was used in subsequent experiments. The noncytotoxic drug concentration of apelin-13 was determined with a Cell Counting Kit-8 (CCK-8) assay. An appropriate dose of apelin-13 (1 μM) significantly improved cell survival (p &lt; 0.05). Thus, subsequent experiments selected a concentration of 1 μM apelin-13 as it significantly increased cell viability. Finally, we divided the experimental groups into four groups according to whether they received drugs (1 μM apelin-13, 24 h) or OGD (6 h): (1) control group: without apelin-13 or OGD injury; (2) apelin-13 group: with apelin-13 but no OGD injury; (3) OGD group: with OGD injury but without apelin-13; and (4) OGD + apelin-13 group: with apelin-13 and OGD injury. The TUNEL assay and flow cytometry results showed that compared with the OGD group, apoptosis in the OGD+Apelin-13 group was significantly reduced (p &lt; 0.001). Determination of cell viability under different conditions by CCK-8 assay results displays that Apelin-13 can significantly improve the cell viability percentage under OGD conditions (p &lt; 0.001). Western blotting results showed that apelin-13 decreased the expression ratios of apoptosis-related proteins Bax/Bcl-2 and cleaved-caspase3/caspase3 (p &lt; 0.05), increasing the key to Beclin1-dependent autophagy pathway expression of the protein Beclin1. This finding indicates that apelin-13 protects neurons by strengthening autophagy and attenuating early-stage postspinal cord injury apoptosis in vitro.

Identification of hub genes regulating the cell activity and function of adipose-derived stem cells under oxygen-glucose deprivation.

While oxygen-glucose deprivation (OGD) has been widely utilized in many cell lines to mimic certain biological changes, it has yet to be validated in mesenchymal stem cells. We performed RNA sequencing on adipose-derived stem cells (ADSCs) under hypoxic and glucose-free conditions after 4h and 8h. A total of 335 common differentially expressed genes (DEGs) were identified in the two OGD groups compared with the normal control group, consisting of 292 upregulated and 43 downregulated genes. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that DEGs are mainly involved in metabolic processes, programmed cell death, and DNA-binding transcription activator activity. Protein‒protein interaction and hub gene analysis revealed various potential hub genes, in which response to oxygen levels, the IL-17-related biological function and the hypoxia-inducible factor 1 signaling pathway have been of vital importance. In summary, changes in transcription factor activity may play pivotal roles in oxygen-glucose deprivation. Through RNA sequencing, we have a deeper understanding of the changes in ADSCs after OGD treatment, providing more precise insight into predicting and regulating the stemness of ADSCs.

Neuroprotection of NSC Therapy is Superior to Glibenclamide in Cardiac Arrest-Induced Brain Injury via Neuroinflammation Regulation.

Cardiac arrest (CA) is common and devastating, and neuroprotective therapies for brain injury after CA remain limited. Neuroinflammation has been a target for two promising butunderdevelopedpost-CA therapies: neural stem cell (NSC) engrafting and glibenclamide (GBC). It is critical to understand whether one therapy has superior efficacy over the other and to further understand their immunomodulatory mechanisms. In this study, we aimed to evaluate and compare the therapeutic effects of NSC and GBC therapies post-CA. Inin vitro studies,BV2 cells underwent oxygen-glucose deprivation (OGD) for three hours and were then treated with GBC or co-cultured with human NSCs (hNSCs). Microglial polarization phenotype and TLR4/NLRP3 inflammatory pathway proteins were detected by immunofluorescence staining. Twenty-four Wistar rats were randomly assigned to three groups (control, GBC, and hNSCs, N = 8/group). After 8min of asphyxial CA, GBC was injected intraperitoneally or hNSCs were administered intranasally in the treatment groups. Neurological-deficit scores (NDSs) were assessed at 24, 48, and 72h after return of spontaneous circulation (ROSC). Immunofluorescence was used to track hNSCs and quantitatively evaluate microglial activation subtype and polarization. The expression of TLR4/NLRP3 pathway-related proteins was quantified via Western blot. The in vitro studies showedthe highest proportion of activated BV2 cells with an increased expression of TLR4/NLRP3 signaling proteins were found in the OGD group compared to OGD + GBC and OGD + hNSCsgroups. NDS showed significant improvement after CAin hNSC and GBC groups compared to controls, and hNSC treatment was superior to GBCtreatment. The hNSC group had more inactive morphology and anti-inflammatory phenotype of microglia. The quantified expression of TLR4/NLRP3 pathway-related proteins was significantly suppressed by both treatments, and the suppression was more significant in the hNSC group compared to the GBC group. hNSC and GBC therapy regulate microglial activation and the neuroinflammatory response in the brain after CA through TLR4/NLRP3 signaling and exert multiple neuroprotective effects, including improved neurological function and shortened time of severe neurological deficit. In addition, hNSCs displayed superior inflammatory regulation over GBC.

Piperine ameliorates ischemic stroke-induced brain injury in rats by regulating the PI3K/AKT/mTOR pathway

Ethnopharmacological relevancePiperine (PIP), a main active component isolated from Piper nigrum L., exerts neuroprotective effects in a rat model of ischemic stroke (IS). However, studies on the effects of PIP on neuroprotection and autophagy after IS are limited. Aim of the studyThis study aimed to prove the protective effects of PIP against brain IS and elucidate its underlying mechanisms. Materials and methodsSpecific pathogen-free male Sprague–Dawley rats were selected to establish a permanent middle cerebral artery occlusion model. The experiment was randomly divided into six groups: sham group, model group, PIP intervention group (10, 20, and 30 mg/kg group), and nimodipine group (Nimo group, 12 mg/kg). Neurological function score, postural reflex score, body swing score, balance beam test, and grip strength test were used to detect behavioral changes of rats. The area of cerebral infarction was detected by TTC staining, and the number and morphological changes of neurons were observed by Nissl and HE staining. In addition, the ultrastructure of hippocampal dentate gyrus neurons was observed using a transmission electron microscope. Western blot was used to detect the expression of PI3K/AKT/mTOR signaling pathway proteins and autophagy-related proteins, namely, Beclin1 and LC3, in the hippocampus and cortex. Cell experiments established an in vitro model of oxygen–glucose deprivation (OGD) with the HT22 cell line to verify the mechanism. The experiment was divided into five groups: control group, OGD group, OGD + PIP 20 μg/mL group, OGD + PIP 30 μg/mL group, and OGD + PIP 40 μg/mL group. CCK-8 was used to measure cell activity, and Western blot was used to measure the expression of PI3K/AKT/mTOR signaling pathway proteins and autophagy-related proteins (Beclin1 and LC3). ResultsCompared with the model group, the neurological function scores, body swing scores, and postural reflex scores of rats in the 10, 20, and 30 mg/kg PIP intervention groups and Nimo groups decreased, whereas the balance beam score and grip test scores increased (all p < 0.05). After 10, 20, and 30 mg/kg PIP and Nimo intervention, the cerebral infarction area of pMCAO rats was reduced (p < 0.01), and Nissl and HE staining results showed that the number of neurons survived in the 30 mg/kg PIP and Nimo intervention groups increased. Cell morphology and structure were significantly improved (p < 0.05). Most of the hippocampal dentate gyrus neurons and their organelles gradually returned to normal in the 30 mg/kg PIP and Nimo intervention groups, with less neuronal damage. The expression levels of p-mTOR, p-AKT, and p-PI3K in the hippocampus and cortex of the 30 mg/kg PIP and Nimo intervention groups decreased, whereas the expression level of PI3K increased (all p < 0.05). In addition, the expression level of autophagy-related proteins, namely, Beclin1 and LC3-II, in the 30 mg/kg PIP and Nimo intervention groups decreased (all p < 0.05). Results of CCK-8 showed that after 1 h of OGD, the 30 and 40 μg/mL PIP intervention groups had higher cell viability than the OGD group (p < 0.01). Western blot results showed that compared with the OGD group, the expression level of p-mTOR, p-AKT, and p-PI3K in the 30 and 40 μg/mL PIP intervention groups decreased, and the expression level of PI3K increased (all p < 0.05). Moreover, the expression level of autophagy-related proteins, namely, Beclin1 and LC3-II, in the 30 and 40 μg/mL PIP intervention groups decreased (all p < 0.05). ConclusionsThis study shows that PIP is a potential compound with neuroprotective effects. PIP can inhibit the PI3K/AKT/mTOR pathway and autophagy. Its inhibition of autophagy is possibly related to modulating the PI3K/AKT/mTOR pathway. These findings provide new insights into the use of PIP for the treatment of IS and its underlying mechanism.

Abstract TP244: Formation Of Neutrophil Extracellular Traps During In Vitro Stroke Facilitates Endothelial Cytotoxicity

Background: Stroke is one of the leading causes of death and disability. Some aspects of inflammation are known to be detrimental and arresting these aspects may improve stroke outcomes. Neutrophils are critical neuroinflammatory mediators and among the first immune cells to respond to the onset of stroke. As the stroke evolves, neutrophils may expel their intracellular contents, referred to as Neutrophil Extracellular Traps (NETs), in a process called NETosis. NETs increase microvascular occlusion and lead to further progression of stroke. However, the interaction of NETs with the cerebral microvascular endothelial cells and the effect of this interaction on stroke outcomes is poorly understood. This project aims to investigate this relationship. Methods: Leukocytes and plasma from C57BL/6 wildtype mice were isolated from whole blood. The leukocytes were then plated in 24-well plates and divided into control and Oxygen Glucose Deprivation (OGD) simulating a stroke environment in vitro. Thereafter, leukocytes were subjected to immunofluorescent staining for neutrophils (Ly6G), and the NETosis markers citrullinated histones (CitH3) and dsDNA. Media from both groups was assayed for Neutrophil Elastase, IL-6, TNF-α, and lactate dehydrogenase (LDH). The remaining media was used to treat primary microvascular endothelial cells to assess inflammation and cell death. Results: Ly6G antibody staining verified that most of the leukocytes plated were neutrophils. The CitH3 and dsDNA immunostaining confirmed induction of NETosis in the OGD group. We also found a significant increase in IL-6 and LDH levels suggesting significant inflammation and cell death in OGD treated leukocytes. Exposure of endothelial cells with NETs enriched media obtained from OGD exposed leukocytes resulted in significant decrease in cell count and increase in IL-6 and LDH levels, suggesting that NETs promoted inflammation and death in the endothelial cells. Nuclear staining of the endothelial cells also exhibited significant decrease in cell count in cohorts treated with the OGD exposed leukocyte media. Conclusion: These pilot data suggest that NETosis may contribute to the cytotoxicity of cerebral endothelial cells during stroke and serve as a potential therapeutic target.

Abstract WP24: Pharmacological Hypothermia (PH) Promotes Plasticity Through RNA Binding Motif 3 (RBM3)-Mediated Cold Shock Pathway Following Ischemic Stroke

Background: Phenothiazine, including chlorpromazine and promethazine (C+P), induce hypothermia and neuroprotection after stroke. Immediately after stroke onset, there is a neuroplasticity window within which rehabilitation is especially effective. Recent studies have indicated that hypothermia-induced neuroplasticity involves the RBM3-mediated cold shock pathway, but it is unknown whether this pathway participates in neuroprotection and neuroplasticity in the context of pharmacological hypothermia (PH) induced by C+P after stroke. Methods: Adult Sprague-Dawley rats were divided in 3 groups: (1) sham; (2) stroke; (3) stroke treated with C+P before reperfusion. Long-term functional outcomes were determined by grid walk tests, rota-rod tests, beam balance tests, forelimb placing tests, adhesive tape touch and adhesive tape removal at 7 through 28 days. mRNA and protein quantities of cold shock pathway [RBM3, eukaryotic initiation factor 2 alpha (eIF2α), and reticulon 3 (RTN3)] and neuroplasticity [synaptophysin (SYN), post-synaptic density protein-95 (PSD-95), Tau, and recombinant growth associated protein 43 (GAP43)] were assessed by real-time PCR and western blot at day 1, 7 and 28 after reperfusion. Additionally, expression of RTN3 and eIF2α, and the co-localization of SYN and PSD95 was measured in primary neurons which subjected to oxygen/glucose deprivation (OGD) with RBM3 knockdown. Results: PH significantly improved functional outcomes at day 7 and 28. At day 1, mRNA and protein expression of RBM3 and RTN3 were significantly increased, and eIF2α was dephosphorylated by PH after stroke. mRNA and protein levels of SYN, Tau and GAP43 were all increased by PH at day 7 and 28. Furthermore, in OGD with shRBM3 group, levels of RTN3 and eIF2α dephosphorylation were significantly decreased, and the co-localization of SYN and PSD95 were significantly reduced compared with OGD group at 24 h without shRBM3. Conclusion: Our study has provided evidence, for the first time, for a novel mechanism underlying hypothermia in which the neuroplasticity and rehabilitation were achieved after ischemic stroke. Our findings suggest that the RBM3-induce cold shock pathway is a potential target of hypothermia for neuroprotection and neurorehabilitation.

F-box and WD repeat domain-containing 7 (FBXW7) mediates the hypoxia inducible factor-1α (HIF-1α)/vascular endothelial growth factor (VEGF) signaling pathway to affect hypoxic-ischemic brain damage in neonatal rats

ABSTRACT The aim of this study was to determine whether F-box and WD repeat domain-containing 7 (FBXW7) can mediate the hypoxia inducible factor-1α (HIF-1α)/vascular endothelial growth factor (VEGF) signaling pathway to affect neonatal hypoxic-ischemic brain damage (HIBD) in neonatal rats. HIBD rats were treated with LV-shFBXW7. Cerebral infarct size was determined by 2,3,5-triphenyltetrazolium chloride (TTC) staining, while microvessel density (MVD) was evaluated by immunohistochemistry. Learning and memory were tested using the Morris water maze (MWM) test. FBXW7 and HIF-1α/VEGF signaling pathway proteins were measured by Western blotting. Brain microvascular endothelial cells (BMECs) were isolated to establish an oxygen-glucose deprivation (OGD) model to evaluate treatment with FBXW7 siRNA. Cell viability was detected using a 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay, while cell migration was evaluated using a wound healing assay. The tube formation of BMECs was also assessed. The results demonstrated that HIBD rats exhibited increased protein expression of FBXW7, HIF-1α, and VEGF. HIBD rats also displayed increased cerebral infarct size, prolonged escape latency and a decreased number of platform crossings. However, HIBD rats treated with LV-shFBXW7 exhibited reversal of these changes. In vitro experiments showed that BMECs in the OGD group had significantly decreased cell viability, shorter vascular lumen length, and shorter migration distance than cells in the control group. Moreover, silencing FBXW7 promoted proliferation, tube formation and migration of BMECs. Taken together, silencing FBXW7 upregulates the HIF-1α/VEGF signaling pathway to promote the angiogenesis of neonatal HIBD rats after brain injury, reducing infarct volume and improving recovery of nerve function in HIBD rats.

Modified Renshen Yangrong decoction enhances angiogenesis in ischemic stroke through promotion of MicroRNA-210 expression by regulating the HIF/VEGF/Notch signaling pathway.

ObjectiveThis study aims to investigate the efficacy of modified Ginseng Yangrong decoction (GSYRD) promoting angiogenesis after ischemic stroke.MethodsIn an in vivo study, rats that survived surgery were allocated into four groups: the control group and model group were treated with normal saline, the GSYRD group was treated with 18.9 mg/kg of GSYRD daily, and the positive control group was treated with Tongxinluo (TXL) (1 g/kg/d). At the end of the seven‐day treatment, the area of cerebral infarction, the expression changes of miRNA‐210 and ephrin A3 were determined. In an in vitro study, HUVECs were divided into a normal control serum group (NC group), normal control serum OGD group (Oxygen Glucose Deprivation group) (OGD group), OGD + drug‐containing serum group (OGD+GSYRD group), and OGD + drug‐containing serum + ES group (Endostatin group) (OGD+GSYRD+ES group). The cells in all groups except the NC group were cultured in a sugar‐free DMEM medium under hypoxia for 48 h. Cell proliferation, angiogenic structure formation ability, the expression changes of miRNA‐210, ephrin A3, and the HIF/VEGF/Notch signaling pathway‐related molecules were determined.ResultsIn vivo, GSYRD significantly reduced infarct size (p < .01), the expression of miRNA‐210 and ephrin A3 were decreased in the GSYRD group (p < .05). In vitro, the cell proliferation and tube formation ability were significantly increased in the GSYRD group (p < .05), and the expression of miRNA‐210 and ephrin A3 was decreased (p < .05). In addition, in the GSYRD group, the expression of the HIF/VEGF/Notch signaling pathway‐related molecules was significantly increased (p < .01 or p < .05).ConclusionGSYRD promotes cerebral protection following angiogenesis and ischemic brain injury. The specific mechanism was activating the HIF/VEGF/Notch signaling pathway via miRNA‐210.

The correlation between the granulocyte colony-stimulating factor and the Notch signaling pathway in ischemic brain injury

IntroductionThis study aims to determine the relationship between the granulocyte colony-stimulating factor (G-CSF) and the Notch signaling pathway in ischemic brain injury.Material and methodsPC-12 cells were treated with the nerve growth factor (NGF) to induce neuronal differentiation then divided into seven groups: 1) no treatment (control); 2) oxygen-glucose deprivation (OGD) model; 3) overexpressed G-CSF + OGD model; 4) transfected empty vector (negative control; NC) + OGD model; 5) overexpressed G-CSF + γ-secretase inhibitor MW167 + OGD model; 6) MW167 + OGD model; and 7) NC + MW167 + OGD model. The cells were analyzed using immunohistochemistry and apoptosis and CCK8 assays. The expression of the related molecules in the Notch pathway was detected using the Western blotting and quantitative PCR (Q-PCR).ResultsMost PC-12 cells were neuron-specific enolase (NSE)-positive after the NGF treatment. When compared with the control group, the MW167 + OGD and NC + MW167 + OGD groups had the lowest optical density (OD) values, followed by the OGD, NC + OGD and the G-CSF + MW167+ OGD groups. The G-CSF + OGD group had the highest OD value. Concerning apoptosis detection, the control group had the lowest apoptosis rate. The highest apoptosis rates were found in the MW167 + OGD, the OGD, and then the G-CSF + OGD groups.ConclusionsThe blocking of the Notch pathway can attenuate the G-CSF effects, whereas the G-CSF overexpression can activate the Notch pathway to resist the effects of oxygen-glucose deprivation.

Nrf2 mediates the neuroprotective effect of isoflurane preconditioning in cortical neuron injury induced by oxygen-glucose deprivation.

To investigate how nuclear factor-E2-related factor 2 (Nrf2) involved in the protective effect of isoflurane (Iso) preconditioning in oxygen glucose deprivation (OGD)-induced cortical neuron injury. Primary mouse cortical neurons were divided into Control, ML385 (an Nrf2 inhibitor), Iso, Iso + ML385, OGD, ML385 + OGD, Iso + OGD, and Iso + ML385 + OGD groups. Lactate dehydrogenase activity (LDH) release and oxidative stress indexes were quantified. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to detect cell viability, Annexin V-FITC/propidium iodide (PI) staining to measure cell apoptosis, dichloro-dihydro-fluorescein diacetate (DCFH-DA) method to test reactive oxygen species (ROS), and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and Western blotting to evaluate genes and protein expression. Iso preconditioning reduced LDH release and inhibited cell cytotoxicity in OGD-induced cortical neurons, which was abolished by ML385. Iso preconditioning increased the Nrf2 nuclear translocation in cortical neurons. Meanwhile, Iso decreased the OGD-induced apoptosis with the down-regulations of Bax and Caspase-3 and the up-regulation of Bcl-2, which was reversed by ML385. OGD enhanced the level of ROS and malondialdehyde (MDA) in cortical neurons, but reduced the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), which were aggravated in ML385 + OGD group and mitigated in Iso + OGD group. No observable difference was found between OGD group and Iso + ML385 + OGD group regarding apoptosis-related proteins and oxidative stress-related indexes. Iso preconditioning up-regulated Nrf2 level to play its protective role in OGD-induced mouse cortical neuron injury.