Neuroprotective effect of osthole against oxygen and glucose deprivation in rat cortical neurons: involvement of mitogen-activated protein kinase pathway

Potential of Natural Products in the Treatment of Glioma: Focus on Molecular Mechanisms

Despite the waning of traditional treatments for glioma due to possible long-term issues, the healing possibilities of substances derived from nature have been reignited in the scientific community. These natural substances, commonly found in fruits and vegetables, are considered potential alternatives to pharmaceuticals, as they have been shown in prior research to impact pathways surrounding cancer progression, metastases, invasion, and resistance. This review will explore the supposed molecular mechanisms of different natural components, such as berberine, curcumin, coffee, resveratrol, epigallocatechin-3-gallate, quercetin, tanshinone, silymarin, coumarin, and lycopene, concerning glioma treatment. While the benefits of a balanced diet containing these compounds are widely recognized, there is considerable scope for investigating the efficacy of these natural products in treating glioma.

Signaling Pathways Involved in the Neuroprotective Effect of Osthole: Evidence and Mechanisms

Neurodegenerative diseases constitute a major threat to human health and are usually accompanied by progressive structural and functional loss of neurons. Abnormalities in synaptic plasticity are involved in neurodegenerative disorders. Aberrant cell signaling cascades play a predominant role in the initiation, progress as well as in the severity of these ailments. Notch signaling is a pivotal role in the maintenance of neural stem cells and also participates in neurogenesis. PI3k/Akt cascade regulates different biological processes including cell proliferation, apoptosis, and metabolism. It regulates neurotoxicity and mediates the survival of neurons. Moreover, the activated BDNF/TrkB cascade is involved in promoting the transcription of genes responsible for cell survival and neurogenesis. Despite significant progress made in delineating the underlying pathological mechanisms involved and derangements in cellular metabolic promenades implicated in these diseases, satisfactory strategies for the clinical management of these ailments are yet to be achieved. Therefore, the molecules targeting these cell signaling cascades may emerge as useful leads in developing newer management strategies. Osthole is an important ingredient of traditional Chinese medicinal plants, often found in various plants of the Apiaceae family and has been observed to target these aforementioned mediators. Until now, no review has been aimed to discuss the possible molecular signaling cascades involved in osthole-mediated neuroprotection at one platform. The current review aimed to explore the interplay of various mediators and the modulation of the different molecular signaling cascades in osthole-mediated neuroprotection. This review could open new insights into research involving diseases of neuronal origin, especially the effect on neurodegeneration, neurogenesis, and synaptic plasticity. The articles gathered to compose the current review were extracted by using the PubMed, Scopus, Science Direct, and Web of Science databases. A methodical approach was used to integrate and discuss all published original reports describing the modulation of different mediators by osthole to confer neuroprotection at one platform to provide possible molecular pathways. Based on the inclusion and exclusion criteria, 32 articles were included in the systematic review. Moreover, literature evidence was also used to construct the biosynthetic pathway of osthole. The current review reveals that osthole promotes neurogenesis and neuronal functioning via stimulation of Notch, BDNF/Trk, and P13k/Akt signaling pathways. It upregulates the expression of various proteins, such as BDNF, TrkB, CREB, Nrf-2, P13k, and Akt. Activation of Wnt by osthole, in turn, regulates downstream GSK-1β to inhibit tau phosphorylation and β-catenin degradation to prevent neuronal apoptosis. The activation of Wnt and inhibition of oxidative stress, Aβ, and GSK-3β mediated β-catenin degradation by osthole might also be involved in mediating the protection against neurodegenerative diseases. Furthermore, it also inhibits neuroinflammation by suppressing MAPK/NF-κB-mediated transcription of genes involved in the generation of inflammatory cytokines and NLRP-3 inflammasomes. This review delineates the various underlying signaling pathways involved in mediating the neuroprotective effect of osthole. Modulation of Notch, BDNF/Trk, MAPK/NF-κB, and P13k/Akt signaling pathways by osthole confers protection against neurodegenerative diseases. The preclinical effects of osthole suggest that it could be a valuable molecule in inspiring the development of new drugs for the management of neurodegenerative diseases and demands clinical studies to explore its potential. An effort has been made to unify the varied mechanisms and target sites involved in the neuroprotective effect of osthole. The comprehensive description of the molecular pathways in the present work reflects its originality and thoroughness. The reviewed literature findings may be extrapolated to suggest the role of othole as a "biological response modifier" which contributes to neuroprotection through kinase modulatory, immunomodulatory, and anti-oxidative activity, which is documented even at lower doses. The current review attempts to emphasize the gaps in the existing literature which can be explored in the future.

Role of SIRT1 in sepsis-induced encephalopathy: Molecular targets for future therapies

Sepsis induces neuroinflammation, BBB disruption, cerebral hypoxia, neuronal mitochondrial dysfunction, and cell death causing sepsis-associated encephalopathy (SAE). These pathological consequences lead to short- and long-term neurobehavioural deficits. Till now there is no specific treatment that directly improves SAE and its associated behavioural impairments. In this review, we discuss the underlying mechanisms of sepsis-induced brain injury with a focus on the latest progress regarding neuroprotective effects of SIRT1 (silent mating type information regulation-2 homologue-1). SIRT1 is an NAD+ -dependent class III protein deacetylase. It is able to modulate multiple downstream signals (including NF-κB, HMGB, AMPK, PGC1α and FoxO), which are involved in the development of SAE by its deacetylation activity. There are multiple recent studies showing the neuroprotective effects of SIRT1 in neuroinflammation related diseases. The proposed neuroprotective action of SIRT1 is meant to bring a promising therapeutic strategy for managing SAE and ameliorating its related behavioural deficits.

Synthesis of Novel 3-Butylphthalide Derivatives Containing Isopentenylphenol Moiety as Potential Antiplatelet Agents for the Treatment of Ischemic Stroke

In order to find novel antiplatelet drugs for the treatment of ischemic stroke, a series of 3-butylphthalide derivatives containing isopentenylphenol moiety were designed, synthesized and characterized with spectroscopic analyses. The in vitro antiplatelet activity results indicated that compound 3 better inhibited the arachidonic acid (AA) induced platelet aggregation than aspirin (ASP) and 3-butylphthalide (NBP). Additionally, compared with precursor NBP, compound 3 possessed outstanding antithrombotic activity in the animal experiment model, which could effectively alleviate the formation of tail thrombus and carotid artery thrombus in mice. More importantly, intraperitoneal administration of compound 3 can well protected the rats against ischemia/reperfusion-induced brain injury. Further pharmacokinetic (PK) assay indicated that compound 3 had good absorption characteristics and metabolic stability in vivo. Overall, the present research provides a new candidate compound for the treatment of ischemic stroke caused by platelet aggregation.

[Inhibition of Sonic Hedgehog signaling inhibits fibrous scar formation and adversely affects functional outcome after ischemic brain injury in rats]

OBJECTIVE

To investigate the effects of inhibiting Sonic Hedgehog (Shh) signaling on fibrous scar formation and functional outcome after ischemic brain injury.

METHODS

Adult SD rats were randomized into sham-operated group, middle cerebral artery occlusion (MCAO) and reperfusion (I/R) group, I/R with intraventricular empty adenoviral vector (rAd-NC) injection group, and I/R with adenovirus-mediated Shh knockdown (rAd-ShShh) group. After the treatments, the neurological deficits of the rats were assessed, and the protein and mRNA expressions of fibronectin (Fn), α-SMA, and Shh in the ischemic hemisphere were detected with immunofluorescence assay and qPCR; TUNEL staining was used for detecting neural cell apoptosis. In the cell experiment, primary meningeal fibroblasts isolated from neonatal SD rats were pretreated for 24 h with TGF-β1 or TGF-β1 plus cyclopamine (CYC) before oxygen-glucose deprivation for 150 min followed by reoxygenation for 72 h (OGD/R). CCK-8 assay and scratch test were performed to examine the changes in cell proliferation and migration, and immunofluorescence assay, qPCR and Western blotting were used for detecting cell transformation and the expressions of Shh, α-SMA, and Fn.

RESULTS

Cerebral I/R injury significantly increased the protein and mRNA expressions of Shh, α-SMA, and Fn in the ischemic hemisphere of the rats, but their expression levels were significantly lowered by intraventricular injection of rAd-Shshh (P < 0.05), which obviously increased cell apoptosis in the ischemic hemisphere (P < 0.05) and improved modified mNSS and modified Bederson scores of the rats (P < 0.05). In the cell experiment, pretreatment with TGF-β1 and TGF-β1+CYC both increased the viability of the primary meningeal fibroblasts after OGD/R. TGF-β1 significantly enhanced the migration ability and induced obvious transformation of the exposed cells (P < 0.05), but these effects were significantly attenuated by co-treatment with CYC (P < 0.05). The expressions of Shh, α-SMA and Fn in the TGF-β1 group were all significantly higher in TGF-β1-treated cells (P < 0.05) and were obviously lowered by co-treatment with CYC (P < 0.05).

CONCLUSION

Inhibition of Shh signaling may inhibit fibrous scar formation and functional recovery in rats after ischemic brain injury.

Sertad1 Induces Neurological Injury after Ischemic Stroke via the CDK4/p-Rb Pathway

SERTA domain-containing protein 1 (Sertad1) is upregulated in the models of DNA damage and Alzheimer's disease, contributing to neuronal death. However, the role and mechanism of Sertad1 in ischemic/hypoxic neurological injury remain unclear. In the present study, our results showed that the expression of Sertad1 was upregulated in a mouse middle cerebral artery occlusion and reperfusion model and in HT22 cells after oxygen-glucose deprivation/reoxygenation (OGD/R). Sertad1 knockdown significantly ameliorated ischemia-induced brain infarct volume, neurological deficits and neuronal apoptosis. In addition, it significantly ameliorated the OGD/R-induced inhibition of cell viability and apoptotic cell death in HT22 cells. Sertad1 knockdown significantly inhibited the ischemic/hypoxic-induced expression of p-Rb, B-Myb, and Bim in vivo and in vitro. However, Sertad1 overexpression significantly exacerbated the OGD/R-induced inhibition of cell viability and apoptotic cell death and p-Rb, B-Myb, and Bim expression in HT22 cells. In further studies, we demonstrated that Sertad1 directly binds to CDK4 and the CDK4 inhibitor ON123300 restores the effects of Sertad1 overexpression on OGD/R-induced apoptotic cell death and p-Rb, B-Myb, and Bim expression in HT22 cells. These results suggested that Sertad1 contributed to ischemic/hypoxic neurological injury by activating the CDK4/p-Rb pathway.

Dehydrocostuslactone attenuated oxygen and glucose deprivation/reperfusion-induced PC12 cell injury through inhibition of apoptosis and autophagy by activating the PI3K/AKT/mTOR pathway

The purpose of this study is to investigate the protective effect of dehydrocostuslactone (DHL) on PC12 cells injury induced by oxygen and glucose deprivation/reperfusion (OGD/R) and its possible mechanism on the PI3K/AKT/mTOR pathway. The maestro 11.1 software was used to predict the binding sites of DHL with LC3, Beclin-1, PI3K, AKT, mTOR, Bax, Bcl-2, Caspase-3, Caspase-9, and Caspase-7. We used a cellular model of 2 h of OGD and 24 h of reperfusion to mimic cerebral ischemia-reperfusion injury. Cells were treated with DHL during the reperfusion phase. The docking results showed that DHL had binding sites with LC3, Beclin-1, PI3K, AKT, mTOR, Bax, Bcl-2, Caspase-3, Caspase-9, and Caspase-7. The expression levels of autophagy-related proteins, LC3 and Beclin-1 increased while P-PI3K, P-AKT, and P-mTOR decreased. Apoptosis-related proteins, namely, Bax, Cyto-c, Caspase-3, Caspase-7, Caspase-9 increased, but the anti-apoptosis Bcl-2 protein decreased. However, DHL effectively inhibited these undesirable changes induced by OGD/R in PC12 cells. Our results suggested that DHL attenuated OGD/R-induced neuronal injury by inhibiting apoptosis and autophagy by activating PI3K/AKT/mTOR signaling. This inhibition can improve cell survival and offer evidence for the beneficial effects of DHL on the nervous system.

Osthole improves pulmonary artery hypertension by inducing apoptosis in pulmonary artery smooth muscle cells

OBJECTIVES

The objectives of this study were to explore the effect of Osthole (Ost) on apoptosis in pulmonary artery smooth muscle cells (PASMCs) and investigate the potential mechanism of this effect.

METHODS

Rats were injected subcutaneously with monocrotaline (MCT) to establish a PAH model, and Ost were intragastrically administrated from day 1 to day 35. After 35 days administration, the mean pulmonary artery pressure and lung weight index were measured. HE and TUNEL staining were used to observe the morphology of pulmonary artery and the apoptosis of PASMCs. In addition, the apoptosis of PASMCs were detected by flow cytometry in cultured PASMCs. The proteins of Bax and Bcl-2, and the levels of p-ASK1 and cleaved caspase 3 were measured by Western blot.

KEY FINDINGS

Ost decreased the mean pulmonary artery pressure and lung weight index in MCT-induced rats, and promoted apoptosis in PASMCs in MCT-induced rats and PDGF-BB stimulated PASMCs. Ost increased the ratio of Bax/Bcl-2 and the levels of p-ASK1, cleaved caspase 3 in MCT-induced rats and PDGF-BB stimulated PASMCs.

CONCLUSION

Ost promoted apoptosis in PASMCs in vivo and in vitro, and the mechanism may be associated with upregulation of ASK1 and the Bax/Bcl-2-caspase 3 signalling pathway.

The AMPAR antagonist perampanel protects the neurovascular unit against traumatic injury via regulating Sirt3

Introduction

Perampanel is a highly selective and noncompetitive α‐amino‐3 ‐hydroxy‐5‐methyl‐4‐isoxazole propionate receptor (AMPAR) antagonist, which has been used as an orally administered antiepileptic drug in more than 55 countries. Recently, perampanel was shown to exert neuroprotective effects in hemorrhagic and ischemic stroke models via regulating blood–brain barrier (BBB) function.

Aim

Here, the protective effects of perampanel were investigated in an in vitro neurovascular unit (NVU) system established using a triple cell co‐culture model (neurons, astrocytes, and brain microvascular endothelial cells) and in an in vivo traumatic brain injury (TBI) model.

Results

Neurons in the NVU system exhibit a more mature morphological phenotype compared with neurons cultured alone, and the co‐culture system mimicked an impermeable barrier in vitro. Perampanel protects the NVU system against traumatic and excitotoxic injury, as evidenced by reduced lactate dehydrogenase (LDH) release and apoptotic rate. Treatment with perampanel attenuated lipid peroxidation and expression of inflammatory cytokines. In addition, perampanel increased Sirt3 protein expression, enhanced the activities of mitochondrial enzyme IDH2 and SOD2, and preserved BBB function in vitro. Knockdown of Sirt3 using specific siRNA (Si‐Sirt3) partially reserved the effects of perampanel on neuronal injury and BBB function. Treatment with perampanel in vivo attenuated brain edema, preserved neurological function, inhibited apoptosis and microglia activation after TBI. Furthermore, perampanel increased the expression of Sirt3 and preserved BBB function after TBI. The effect of perampanel on BBB function and brain edema was abolished by knockdown of Sirt3 in vivo.

Conclusion

Our results indicate that the noncompetitive AMPAR antagonist perampanel protects the NVU system and reduces brain damage after TBI via activating the Sirt3 cascades.

Design, synthesis and biological evaluation of novel osthole-based derivatives as potential neuroprotective agents

A total of 26 compounds based on osthole skeleton were designed, synthesized. Their cytoprotective abilities of antioxidation, anti-inflammation and Aβ₄₂(Amyloid β-protein 42)-induced neurotoxicity were evaluated by MTT assays. Mechanism of the action of selected compounds were investigated by molecular docking. AlogP, logS and blood-brain barrier (BBB) permeability of all these compounds were simulated by admetSAR. Most of the compounds showed better antioxidative and anti-inflammatory activities compared with osthole, especially OST7 and OST17. The compound OST7 showed relative high activity in neuroprotection against H₂O₂ (45.7 ± 5.5%), oxygen glucose deprivation (64.6 ± 4.8%) and Aβ₄₂ (61.4 ± 5.2%) at a low concentration of 10 μM. EC₅₀ of selected compounds were measured in both H₂O₂ and OGD induced cytotoxicity models. Moreover, NO inhibiting ability of OST17(50.4 ± 7.1%) already surpassed the positive drug indomethacin. The structure activity relationship study indicated that introduction of piperazine group, tetrahydropyrrole group and aromatic amine group might be beneficial for enhancement of osthole neuroprotective properties. Molecular docking explained that the reason OST7 exhibited relatively stronger neuroprotection against Aβ because of the greater area of interactions between molecule and target protein. OST7 and OST17 both provided novel methods to investigate osthole as anti-AD drugs.

Multifunctional osthole liposomes and brain targeting functionality with potential applications in a mouse model of Alzheimer's disease

Osthole (Ost) is a coumarin compound and a potential drug for Alzheimer's disease (AD). However, the effectiveness of Ost is limited by solubility, bioavailability, and low permeability of the blood-brain barrier. In this study, we constructed Ost liposomes with modified CXCR4 on the surface (CXCR4-Ost-Lips), and investigated the intracellular distribution of liposomes in APP-SH-SY5Y cells. In addition, the neuroprotective effect of CXCR4-Ost-Lips was examined in vitro and in vivo. The results showed that CXCR4-Ost-Lips increased intracellular uptake by APP-SH-SY5Y cells and exerted a cytoprotective effect in vitro. The results of Ost brain distribution showed that CXCR4-Ost-Lips prolonged the cycle time of mice and increased the accumulation of Ost in the brain. In addition, CXCR4-Ost-Lips enhanced the effect of Ost in relieving AD-related pathologies. These results indicate that CXCR4-modified liposomes are a potential Ost carrier to treat AD.

MCC950, a Selective Inhibitor of NLRP3 Inflammasome, Reduces the Inflammatory Response and Improves Neurological Outcomes in Mice Model of Spinal Cord Injury

Spinal cord injury (SCI) is a serious condition that affects bodily function; however, there is no effective therapy in clinical practice. MCC950, a selective NOD-like receptor protein-3 (NLRP3) inflammasome inhibitor, has been reported to alleviate canonical and non-canonical NLRP3 inflammasome activation of the inflammatory response in vitro and in vivo. However, the effect of MCC950 treatment on neurological post-SCI recovery remains unclear. In this study, we assessed the pharmacological effect of MCC950 on an experimental SCI model in vivo and neuronal injury in vitro. We found that MCC950 improved the grip strength, hind limb movements, spinal cord edema, and pathological injury in the SCI mice. We demonstrated that it exerted this effect by blocking NLRP3 inflammasome assembly, including NLRP3-ASC and NLRP3-Caspase-1 complexes, as well as the release of pro-inflammatory cytokines TNF-α, IL-1β, and IL-18. Moreover, we found that MCC950 reduced spinal neuron injury and NLRP3 inflammasome activation, which had been induced by oxygen–glucose deprivation (OGD) or lipopolysaccharides (LPS) in vitro. In conclusion, our findings indicate that MCC950 alleviates inflammatory response and improves functional recovery in the acute mice model of SCI by blocking NLRP3 inflammasome assembly and alleviating downstream neuroinflammation. Therefore, these findings could prove useful in the development of effective therapeutic strategies for the treatment and prognosis of SCI.

Expression Profiles of MicroRNAs in Stem Cells Differentiation

Stem cells are undifferentiated cells and have a great potential in multilineage differentiation. These cells are classified into adult stem cells like Mesenchymal Stem Cells (MSCs) and Embryonic Stem Cells (ESCs). Stem cells also have potential therapeutic utility due to their pluripotency, self-renewal, and differentiation ability. These properties make them a suitable choice for regenerative medicine. Stem cells differentiation toward functional cells is governed by different signaling pathways and transcription factors. Recent studies have demonstrated the key role of microRNAs in the pathogenesis of various diseases, cell cycle regulation, apoptosis, aging, cell fate decisions. Several types of stem cells have different and unique miRNA expression profiles. Our review summarizes novel regulatory roles of miRNAs in the process of stem cell differentiation especially adult stem cells into a variety of functional cells through signaling pathways and transcription factors modulation. Understanding the mechanistic roles of miRNAs might be helpful in elaborating clinical therapies using stem cells and developing novel biomarkers for the early and effective diagnosis of pathologic conditions.

PDE9 inhibition promotes proliferation of neural stem cells via cGMP-PKG pathway following oxygen-glucose deprivation/reoxygenation injury in vitro

Cerebral ischemia is one of leading causes of death and long-term disability worldwide. Stem cell-based therapy is promising some valuable strategies for the structural and functional recovery after ischemic insult. The inhibition of phosphodiesterases (PDEs) has wide spectrum neuroprotective properties by stimulating proliferation of neural stem cells (NSCs). However, the potential role of PDE9 on NSCs proliferation after cerebral ischemia is not well investigated. The present study aimed to assess the contribution of PDE9 inhibition on the proliferation of NSCs and to determine the details of its underlying mechanisms against cerebral ischemia. The survival and proliferation of NSCs were assessed by CCK-8 assay and BrdU immunofluorescence staining, respectively. PDE9 activity and cGMP level were measured by ELISA kits. The protein expression of PKG and BDNF was detected by Western blot. Exposing NSCs of cultured primary hippocampus to oxygen-glucose deprivation/reoxygenation (OGD/R) significantly decreased the survival rate, but increased the proliferation of NSCs. Meanwhile, PDE9 activity was decreased, cGMP level was increased, PKG and BDNF protein expression was increased. PF-04447953, a PDE9 inhibitor, increased the survival rate of NSCs, moreover, PDE9 activity reduced more, and NSCs proliferation, cGMP level, PKG and BDNF protein expression were increased further, compared with OGD/R model group. These effects of PF-04447953, except for PDE9 activity and cGMP level, were reversed by treatment with KT5823, a PKG inhibitor. Taken together, the inhibition of PDE9 can promote the proliferation of NSCs following OGD/R injury, which may be, at least partly, mediated by cGMP-PKG pathway.

Osthole alleviates MPTP-induced Parkinson's disease mice by suppressing Notch signaling pathway

Objectives: Parkinson's disease (PD) is an age-related neurodegenerative disease characterized by motor dysfunctions. Dopaminergic neuron loss, inflammation and oxidative stress responses play key roles in the pathogenisis of PD. Osthole (Ost), a natural coumarin derivative, isolated from various herbs such as Cnidium monnieri (L.), has anti-inflammatory, anti-apoptotic and anti-oxidative stress properties. However, whether it has effects on PD is unknown. Methods: In this study, mice were subjected to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) injection to induce PD symptoms, and treated with osthole. Stepping and cylinder tests were performed to determine their motor function. Immunohistochemical and immunofluorescence staining were performed to detect tyrosine hydroxylase (TH) and ionized calcium binding adaptor molecule 1 (Iba-1). The expression levels of inflammatory cytokines and oxidative stress factors were detected by qPCR and ELISA. Notch signaling pathway was investigated by western blot. Results: We found that injection of MPTP induced motor deficits in mice, enhanced the loss dopaminergic neurons and the activation of microglia, increased inflammatory and oxidative stress responses, and inhibited Notch signaling pathway. Osthole treatment suppressed theses MPTP-induced alterations. Conclusion: In conclusion, osthole attenuates PD symptoms by suppressing Notch signaling pathway.

Bazedoxifene protects cerebral autoregulation after traumatic brain injury and attenuates impairments in blood-brain barrier damage: involvement of anti-inflammatory pathways by blocking MAPK signaling

OBJECTIVE

Traumatic brain injury (TBI) is a significant cause of death and long-term deficits in motor and cognitive functions for which there are currently no effective chemotherapeutic drugs. Bazedoxifene (BZA) is a third-generation selective estrogen receptor modulator (SERM) and has been investigated as a treatment for postmenopausal osteoporosis. It is generally safe and well tolerated, with favorable endometrial and breast safety profiles. Recent findings have shown that SERMs may have therapeutic benefits; however, the role of BZA in the treatment of TBI and its molecular and cellular mechanisms remain poorly understood. The aim of the present study was to examine the neuroprotective effects of BZA on early TBI in rats and to explore the underlying mechanisms of these effects.

MATERIALS AND METHODS

TBI was induced using a modified weight-drop method. Neurological deficits were evaluated according to the neurological severity score (NSS). Morris water maze and open-field behavioral tests were used to test cognitive functions. Brain edema was measured by brain water content, and impairments in the blood-brain barrier (BBB) were evaluated by expression analysis of tight junction-associated proteins, such as occludin and zonula occludens-1 (ZO-1). Neuronal injury was assessed by hematoxylin and eosin (H&E) staining. LC-MS/MS analysis was performed to determine the ability of BZA to cross the BBB.

RESULTS

Our results indicated that BZA attenuated the impaired cognitive functions and the increased BBB permeability of rats subjected to TBI through activation of inflammatory cascades. In vivo experiments further revealed that BZA provided this neuroprotection by suppressing TBI-induced activation of the MAPK/NF-κB signaling pathway. Thus, mechanically, the anti-inflammatory effects of BZA in TBI may be partially mediated by blocking the MAPK signaling pathway.

CONCLUSIONS

These findings suggest that BZA might attenuate neurological deficits and BBB damage to protect against TBI by blocking the MAPK/NF-κB signaling pathway.

Osthole Synergizes With HER2 Inhibitor, Trastuzumab in HER2-Overexpressed N87 Gastric Cancer by Inducing Apoptosis and Inhibition of AKT-MAPK Pathway

Background and Purpose: Although trastuzumab has shown considerable activity in the treatment of HER2-positive breast and gastric cancers, a significant proportion of patients do not respond to trastuzumab. Recent studies revealed that osthole, an active coumarin isolated from Cnidium monnieri (L.) Cusson possesses potent anti-tumor activity. Here, we for the first time investigated the anti-tumor activity of trastuzumab in combination with osthole in HER2-overexpressing cancers.

Materials and Methods: N87 and SK-BR-3 cell lines, which were HER2-overexpressing cancer cells were used in our study. Cell Counting Kit-8 (CCK-8) assay was utilized to test the inhibitory effects of trastuzumab plus osthole. Combination index (CI) values were calculated using the Chou-Talalay method. Fluorescence-Activated Cell Sorter (FACS) assay was used to examine the cell cycle change and apoptosis upon combinatorial treatment. N87 tumor xenografts were established to evaluate in vivo effects of trastuzumab plus osthole. In addition, molecular mechanisms were analyzed by Western blot in vitro and in vivo.

Results: As shown in our study, osthole alone exhibited effective anti-tumor activity against HER2-overexpressed N87 gastric cancer cells and SK-BR-3 breast cancer cells, which may be attributed to cell cycle arrest on G2/M phase and apoptosis. More importantly, our data demonstrated that trastuzumab plus osthole was much more potent than either agent alone in inhibiting the growth of N87 cancer cells in vitro and in vivo, which may be partly explained by the enhanced apoptosis upon the combinatorial treatment. Besides these, we also observed a significant decrease on the phosphorylation of AKT and MAPK in N87 cells when treated with trastuzumab plus osthole compared to either agent alone. Further data from N87 tumor xenografts revealed that trastuzumab plus osthole exerted their synergistic effects mainly on AKT signaling pathway.

Conclusion: Collectively, these results support the clinical development of combination osthole with trastuzumab for the treatment of HER2-overexpressed gastric cancer.

Resveratrol Treatment in Different Time-Attenuated Neuronal Apoptosis After Oxygen and Glucose Deprivation/Reoxygenation via Enhancing the Activation of Nrf-2 Signaling Pathway In Vitro

Recent studies have indicated that resveratrol has protective effects against cerebral ischemia/reperfusion injury. However, the best therapeutic time for resveratrol treatment after acute ischemic stroke remains unknown. We aim to investigate whether resveratrol, administrated at different times after neuronal oxygen and glucose deprivation/reoxygenation (OGD/R) reduced neuronal injury in vitro. There were six experimental groups: normal, model, resveratrol pretreatment, resveratrol post-treatment, resveratrol OGD-treatment, and resveratrol whole-processing group. We found that resveratrol in a concentration-dependent manner decreased the activity of lactate dehydrogenase (LDH) and increased the activity of superoxide dismutase (SOD). Moreover, resveratrol, administrated at different times, increased neuronal viability, reduced neuronal apoptosis, upregulated the protein expressions of Nuclear factor erythroid 2-related factor 2 (Nrf-2), NAD(P)H: quinone oxidoreductase 1 (NQO-1), heme oxygenase 1 (HO-1), and Bcl-2, downregulated the protein expression of Caspase-3, and promoted Nrf-2 to transfer into the nuclei from the cytoplasm. The most effective treatment group was the whole-processing treatment group. These results suggest that resveratrol treatment at different times increased neuronal viability and inhibited neuronal apoptosis in vitro, at least in part, via enhancing the activation of the Nrf-2 signaling pathway.

Neuroprotective effects of metformin on traumatic brain injury in rats associated with NF-κB and MAPK signaling pathway

Traumatic brain injury (TBI) triggers a complex sequence of inflammatory responses that contribute to secondary injury. Metformin, a first-line drug used to treat type 2 diabetes, is reported to exhibit potent anti-inflammatory activity on diseases associated with the central nervous system (CNS). The aim of this study is to investigate the potential neuroprotective effects of metformin on acute brain injury after TBI and explore the underlying mechanisms. Male Sprague-Dawley (SD) rats were divided into four groups: sham group, TBI group, TBI + saline (NS) group and TBI + metformin group. A weight-dropping model was employed to induce TBI in rats. Modified neurological severity scores (mNSS) were employed to assess the short-term neurological deficits, neuronal degeneration and apoptosis in the brain tissues were assayed with Fluoro-Jade B and TUNEL staining, immunofluorescence was designed to investigate microglial activation. The mRNA and protein expression levels of pro-inflammatory cytokines such as necrosis factor-alpha (TNF-α), interleukin-beta (IL-1β) and nterleukin-6 (IL-6) were evaluated by real-time quantitative reverse transcriptase polymerase chain reaction (QPCR) and enzyme-linked immunosorbent assay (ELISA). Western blotting analysis was engaged to examine the expression of NF-κB p65 and phosphorylation of ERK1/2 and p38 MAPK. Our results showed that metformin significantly ameliorated neurological deficit, cerebral edema and neuronal apoptosis in rats following TBI. Moreover, metformin administration inhibited microglial activation and decreased the production of pro-inflammatory cytokines including TNF-α, IL-1β and IL-6. In addition, metformin inhibited the translocation of NF-κB p65 from cytoplasm into the nucleus, as well as the phosphorylation of ERK1/2 and p38 MAPK. This study suggests that metformin administration inhibits microglia activation-mediated inflammation via NF-κB and MAPK signaling pathway to improve neurobehavioral function following TBI, which provide a potential therapeutic benefit in treating brain injury.

Lentivirus-mediated overexpression of OTULIN ameliorates microglia activation and neuroinflammation by depressing the activation of the NF-κB signaling pathway in cerebral ischemia/reperfusion rats

Background

Ischemic stroke-induced neuroinflammation is mainly mediated by microglial cells. The nuclear factor kappa B (NF-κB) pathway is the key transcriptional pathway that initiates inflammatory responses following cerebral ischemia. OTULIN, a critical negative regulator of the NF-κΒ signaling pathway, exerts robust effects on peripheral immune cell-mediated inflammation and is regarded as an essential mediator for repressing inflammation in vivo. The effect of OTULIN on inflammatory responses in the central nervous system (CNS) was previously unstudied. This current study investigated the anti-inflammatory effect of OTULIN both in vitro and in vivo in ischemic stroke models.

Methods

Sprague-Dawley (SD) rats were subjected to transient middle cerebral artery occlusion (tMCAO) or an intraperitoneal injection of lipopolysaccharide (LPS). Overexpression of the OTULIN gene was utilized to observe the effect of OTULIN on ischemic stroke outcomes. The effect of OTULIN overexpression on microglia-mediated neuroinflammation was examined in rat primary microglia (PM) and in the microglial cell line N9 after induction by oxygen-glucose deprivation (OGD)-treated neuronal medium. The activation and inflammatory responses of microglia were detected using immunofluorescence, ELISA, and qRT-PCR. The details of molecular mechanism were assessed using Western blotting.

Results

In the tMCAO rats, the focal cerebral ischemia/reperfusion injury induced a continuous increase in OTULIN expression within 72 h, and OTULIN expression was increased in activated microglial cells. OTULIN overexpression obviously decreased the cerebral infarct volume, improved the neurological function deficits, and reduced neuronal loss at 72 h after reperfusion, and it also inhibited the activation of microglia and attenuated the release of TNF-α, IL-1β, and IL-6 by suppressing the NF-κB pathway at 24 h after tMCAO. In vitro, OTULIN overexpression inhibited the microglia-mediated neuroinflammation by reducing the production of TNF-α, IL-1β, and IL-6 via depressing the NF-κB pathway in both PM and N9 cells.

Conclusions

OTULIN provides a potential therapeutic target for ischemic brain injury by ameliorating the excessive activation of microglial cells and neuroinflammation through repressing the NF-κB signaling pathway.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1117-5) contains supplementary material, which is available to authorized users.

Neuroprotective Effect of Oxysophocarpine by Modulation of MAPK Pathway in Rat Hippocampal Neurons Subject to Oxygen-Glucose Deprivation and Reperfusion

Oxysophocarpine (OSC), an alkaloid isolated from Sophora flavescens Ait, has been traditionally used as a medicinal agent based on the observed pharmacological effects. In this study, the direct effect of OSC against neuronal injuries induced by oxygen and glucose deprivation (OGD) in neonatal rat primary-cultured hippocampal neurons and its mechanisms were investigated. Cultured hippocampal neurons, which were exposed to OGD for 2 h followed by a 24 h reoxygenation, were used as an in vitro model of ischemia and reperfusion. 2-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and lactate dehydrogenase (LDH) assay were used to confirm neural damage and to further evaluate the protective effects of OSC. The concentration of intracellular-free calcium [Ca2+]i and mitochondrial membrane potential (MMP) were measured to determine the intracellular mechanisms and to further estimate the degree of neuronal damage. Changes in expression of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, p-ERK1/2, p-JNK1/2, and p-p38 MAPK were also observed in the in vitro model. It was shown that OSC (0.8, 2, or 5 µmol/L) significantly attenuated the increased absorbance of MTT, and the release of LDH manifests the neuronal damage by the OGD/R. Meanwhile, the pretreatment of the neurons during the reoxygenation period with OSC significantly increased MMP; it also inhibited [Ca2+]i the elevation in a dose-dependent manner. Furthermore, the pretreatment with OSC (0.8, 2, or 5 µmol/L) significantly down-regulated expressions of IL-1β, TNF-α, p-ERK1/2, p-JNK1/2, and p-p38 MAPK in neonatal rat primary-cultured hippocampal neurons induced by OGD/R injury. In conclusion, OSC displays a protective effect on OGD-injured hippocampal neurons by attenuating expression of inflammatory factors via down-regulated the MAPK signaling pathway.

Sirt3-Mediated Autophagy Contributes to Resveratrol-Induced Protection against ER Stress in HT22 Cells

Endoplasmic reticulum (ER) stress occurring in stringent conditions is critically involved in neuronal survival and death. Resveratrol is a non-flavonoid polyphenol that has neuroprotective effects against many neurological disorders. Here, we investigated the potential protective effects of resveratrol in an in vitro ER stress model mimicked by tunicamycin (TM) treatment in neuronal HT22 cells. We found that TM dose-dependently decreased cell viability and increased apoptosis, which were both significantly attenuated by resveratrol treatment. Resveratrol markedly reduced the expression or activation of ER stress-associated factors, including GRP78, CHOP, and caspase-12. The results of immunocytochemistry and western blot showed that resveratrol promoted autophagy in TM-treated cells, as evidenced by increased LC3II puncta number, bcelin1 expression and LC3II/LC3I ratio. Pretreatment with the autophagy inhibitor chloroquine could reduce the protective effects of resveratrol. In addition, the expression of Sirt3 protein and its downstream enzyme activities were significantly increased in resveratrol-treated HT22 cells. To confirm the involvement of Sirt3-mediated mechanisms, siRNA transfection was used to knockdown Sirt3 expression in vitro. The results showed that downregulation of Sirt3 could partially prevented the autophagy and protection induced by resveratrol after TM treatment. Our study demonstrates a pivotal role of Sirt3-mediated autophagy in mediating resveratrol-induced protection against ER stress in vitro, and suggests the therapeutic values of resveratrol in ER stress-associated neuronal injury conditions.

Osthole promotes endogenous neural stem cell proliferation and improved neurological function through Notch signaling pathway in mice acute mechanical brain injury

Mechanical brain injury (MBI) is a common neurotrosis disorder of the central nervous system (CNS), which has a higher mortality and disability. In the case of MBI, neurons death leads to loss of nerve function. To date, there was no satisfactory way to restore neural deficits caused by MBI. Endogenous neural stem cells (NSCs) can proliferate, differentiate and migrate to the lesions after brain injury, to replace and repair the damaged neural cells in the subventricular zone (SVZ), hippocampus and the regions of brain injury. In the present study, we first prepared a mouse model of cortical stab wound brain injury. Using the immunohistochemical and hematoxylin-eosin (H&E) staining method, we demonstrated that osthole (Ost), a natural coumarin derivative, was capable of promoting the proliferation of endogenous NSCs and improving neuronal restoration. Then, using the Morris water maze (MWM) test, we revealed that Ost significantly improved the learning and memory function in the MBI mice, increased the number of neurons in the regions of brain injury, hippocampus DG and CA3 regions. Additionally, we found that Ost up-regulated the expression of self-renewal genes Notch 1 and Hes 1. However, when Notch activity was blocked by the γ-secretase inhibitor DAPT, the expression of Notch 1 and Hes 1 mRNA was down-regulated, augmentation of NICD and Hes 1 protein was ameliorated, the proliferation-inducing effect of Ost was abolished. These results suggested that the effects of Ost were at least in part mediated by activation of Notch signaling pathway. Our findings support that Ost is a potential drug for treating MBI due to its neuronal restoration.

Neuroprotective effects of allicin on ischemia-reperfusion brain injury

BACKGROUND

Ischemia-reperfusion brain injury (IRBI) is an important cause for mortality and morbidity. Studies on humans and animals showed that oxidative stress (OS) plays a crucial role in ischemic stroke with or without reperfusion. Allicin is reported to be able to attenuate OS and has neuroprotective effects on rabbits' ischemia-reperfusion spinal cord injury.

AIM

To explore whether Allicin pretreatment has neuroprotective effects on IRBI in mice.

METHODS AND RESULTS

Transient middle cerebral artery occlusion (MCAO) was conducted to induce IRBI in mice. The mice were pretreated with either Allicin (MCAOA) or normal saline in the same volume (MCAONS). Sham-operated groups [Allicin group (SOA) and normal saline group (SONS)] were also set. Blood pressure and cerebral blood flow measurements revealed comparable hemodynamics. Via brain MRI and neuronal nuclear antigen (NeuN) immune-histochemical staining, MCAOA mice had a significantly reduced stroke size than MCAONS mice (P < 0.05, n = 15). Allicin pretreatment could attenuate the OS, the activity of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, inflammation, dysfunction of mitochondrial respiratory chain, and apoptosis (all P < 0.05, n = 15). Furthermore, Allicin also increased the activities of endogenous antioxidant enzymes, including catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX), and glutathione S-transferase (GST), and promoted the angiogenesis in the peri-infarct zone (all P < 0.05, n = 15).

CONCLUSION

We showed that Allicin could protect mice from IRBI through a series of mechanisms. Allicin represents a new therapeutic direction of IRBI.

Mfn2-Mediated Preservation of Mitochondrial Function Contributes to the Protective Effects of BHAPI in Response to Ischemia

Disturbances in intracellular iron homeostasis are associated with neuronal injury after stroke. However, exposure of cells to classical chelators may interfere with physiological iron functions. BHAPI is an iron prochelator that exerts strong iron binding capacity only under oxidative stress conditions. This study investigated the protective effects of N'-(1-(2-((4-(4,4,5,5-tetramethyl-1,2,3-dioxoborolan-2-yl)benzyl)oxy)phenyl)ethylidene (BHAPI) on an in vitro ischemia model mimicked by oxygen and glucose deprivation (OGD) in neuronal HT22 cells. The results showed that BHAPI significantly increased cell viability and decreased lactate dehydrogenase (LDH) release after OGD. BHAPI treatment also reduced apoptosis, as measured by flow cytometry, and suppressed caspase-3 activation. These protective effects were accompanied by preserved mitochondrial membrane potential (MMP), reduced mitochondrial swelling, promoted mitochondrial calcium buffering capacity, and increased mitochondrial respiration. The results of MitoTracker staining showed that BHAPI partially prevented the OGD-induced changes in mitochondrial morphology. Furthermore, BHAPI selectively increased the expression of mitochondrial dynamic protein Mfn2, with no effect on Mfn1 expression. Knockdown of Mfn2 with specific siRNA partially reversed the protective effects of BHAPI. In summary, the iron prochelator BHAPI protects HT22 cells against ischemic injury through preservation of mitochondrial function and Mfn2 signaling.

Sirt3 confers protection against neuronal ischemia by inducing autophagy: Involvement of the AMPK-mTOR pathway

Sirtuin3 (Sirt3) is a member of the silent information regulator 2 (Sir2) family of proteins located in mitochondria that influences almost every major aspect of mitochondrial biology, including ATP generation and reactive oxygen species (ROS) production. Our previous study showed that Sirt3 exerts protective effects against oxidative stress in neuronal cells. In this study, we investigated the role of Sirt3 in neuronal ischemia using an oxygen and glucose deprivation (OGD) model. Sirt3 was up-regulated by OGD and overexpression of Sirt3 through lentivirus transfection significantly reduced OGD-induced lactate dehydrogenase (LDH) release and neuronal apoptosis. These effects were accompanied by reduced hydrogen dioxide (H₂O₂) production, enhanced ATP generation and preserved mitochondrial membrane potential (MMP). The results of immunocytochemistry and electron microscopy showed that Sirt3 increased autophagy in OGD-injured neurons, which was also confirmed by the increased expression of Beclin-1 as well as LC3-I to LC3-II conversion. In addition, the autophagy inhibitor 3-MA and bafilomycin A1 partially prevented the effects of Sirt3 on LDH release and apoptosis after OGD. The results of western blotting showed that overexpression of Sirt3 in cortical neurons markedly increased the phosphorylation of AMPK, whereas the phosphor-mTOR (p-mTOR) levels decreased both in the presence and absence of OGD insult. Furthermore, pre-treatment with the AMPK inhibitor compound C partially reversed the protective effects of Sirt3. Taken together, these findings demonstrate that Sirt3 protects against OGD insult by inducing autophagy through regulation of the AMPK-mTOR pathway and that Sirt3 may have therapeutic value for protecting neurons from cerebral ischemia.

Osthole Stimulated Neural Stem Cells Differentiation into Neurons in an Alzheimer's Disease Cell Model via Upregulation of MicroRNA-9 and Rescued the Functional Impairment of Hippocampal Neurons in APP/PS1 Transgenic Mice

Alzheimer's disease (AD) is the most serious neurodegenerative disease worldwide and is characterized by progressive cognitive impairment and multiple neurological changes, including neuronal loss in the brain. However, there are no available drugs to delay or cure this disease. Consequently, neuronal replacement therapy may be a strategy to treat AD. Osthole (Ost), a natural coumarin derivative, crosses the blood-brain barrier and exerts strong neuroprotective effects against AD in vitro and in vivo. Recently, microRNAs (miRNAs) have demonstrated a crucial role in pathological processes of AD, implying that targeting miRNAs could be a therapeutic approach to AD. In the present study, we investigated whether Ost could enhance cell viability and prevent cell death in amyloid precursor protein (APP)-expressing neural stem cells (NSCs) as well as promote APP-expressing NSCs differentiation into more neurons by upregulating microRNA (miR)-9 and inhibiting the Notch signaling pathway in vitro. In addition, Ost treatment in APP/PS1 double transgenic (Tg) mice markedly restored cognitive functions, reduced Aβ plague production and rescued functional impairment of hippocampal neurons. The results of the present study provides evidence of the neurogenesis effects and neurobiological mechanisms of Ost against AD, suggesting that Ost is a promising drug for treatment of AD or other neurodegenerative diseases.

Osthole, a Coumadin Analog from Cnidium monnieri (L.) Cusson, Ameliorates Nucleus Pulposus-Induced Radicular Inflammatory Pain by Inhibiting the Activation of Extracellular Signal-Regulated Kinase in Rats

Aim: This study was aimed at assessing the role of extracellular signal regulated kinase (ERK) in mechanical allodynia resulting from lumbar disc herniation (LDH) and exploring the osthole's anti-nociceptive effect on ERK activation. Methods: Radicular pain was generated by applying nucleus pulposus (NP) to the L5 dorsal root ganglion (DRG). Allodynia was measured using Von Frey filaments to calculate the mechanical pain threshold. Phosphorylated ERK and total ERK protein in the lumbar spinal dorsal horn was detected by using the Western blot technique. Cyclooxygenase 2 (COX-2) mRNA was assessed by real-time reverse-transcription polymerase chain reaction. Results: The application of NP to L5 DRG induced mechanical hypersensitivity which lasted for at least 28 days, and a significant increase of ERK phosphorylation in the ipsilateral spinal dorsal horn from postoperative day (POD) 1 to POD 21. ERK inhibitor attenuated NP-induced hyperalgesia compared to the dimethyl sulfoxide-(vehicle control) administered group (p < 0.05). Epidural treatment with osthole could ameliorate NP-evoked hyperalgesia by suppressing the activation of ERK rather than decreasing the expression of ERK protein. Osthole could also inhibit the increased expression of COX-2 mRNA in spinal dorsal horn, which was a known downstream effect of ERK signaling pathway. Conclusions: Our results suggest that ERK activation in the spinal dorsal horn plays a vital role in NP-evoked hyperalgesia. Osthole exerts analgesic effect on radicular inflammatory pain in LDH rat model, by down-regulating the mRNA expression of the target gene of COX-2 via inhibiting ERK activation in the spinal dorsal horn.

Different effects of (+)‑borneol and (‑)‑borneol on the pharmacokinetics of osthole in rats following oral administration

Osthole is the primary active component of a number of herbal plants such as the Cnidium monnieri fruit. In traditional Chinese herb medicine, osthole is commonly used in combination with borneol to obtain improved pharmacological effects. The aim of the present study was to investigate the effect of borneol enantiomers on the pharmacokinetics of osthole. An appropriate high‑performance liquid chromatography (HPLC) method was applied to determine the concentrations of osthole in plasma. Following oral administration of osthole alone or combined with borneol in rats, blood samples were collected and analyzed by HPLC. The results demonstrated that there were statistically significant differences in the pharmacokinetic parameters of osthole between osthole administration alone and co‑administration with borneol. When combined with synthetic borneol, the AUC0‑t, AUC0‑∞ and Cmax of osthole increased by 48.153, 104.708 and 92.630%, respectively, while the CL/F decreased by 51.251%. When combined with (+)‑borneol, the AUC0‑t, AUC0‑∞ and Cmax of osthole were increased by 61.561, 78.167, and 51.769%, respectively, while the CL/F decreased by 44.174% (P<0.01). In addition, when combined with (‑)‑borneol, the AUC0‑t, AUC0‑∞ and Cmax of osthole increased by 115.856, 167.786 and 271.289%, respectively, while the CL/F decreased by 60.686% (P<0.01). These results indicated that borneol may enhance gastrointestinal absorption and inhibit the metabolism of osthole. In addition, the promotional effect of (‑)‑borneol on the pharmacokinetic parameters of osthole was greater than that of (+)‑borneol.

ZL006 protects spinal cord neurons against ischemia-induced oxidative stress through AMPK-PGC-1α-Sirt3 pathway

Spinal cord ischemia (SCI) induces a range of cellular and molecular cascades, including activation of glutamate receptors and downstream signaling. Post-synaptic density protein 95 (PSD-95) links neuronal nitric oxide synthase (nNOS) with the N-methyl-d-aspartic acid (NMDA) receptors to form a ternary complex in the CNS. This molecular complex-mediated cytotoxicity has been implicated in brain ischemia, but its role in SCI has not been determined. The goal of the study was to investigate the potential protective effects of ZL006, a small-molecule inhibitor of the PSD-95/nNOS interaction, in an in vitro SCI model induced by oxygen and glucose deprivation (OGD) in cultured spinal cord neurons. We found that ZL006 reduced OGD-induced lactate dehydrogenase (LDH) release, neuronal apoptosis and loss of cell viability. This protection was accompanied by the preservation of mitochondrial function, as evidenced by reduced mitochondrial oxidative stress, attenuated mitochondrial membrane potential (MMP) loss, and enhanced ATP generation. In addition, ZL006 stimulated mitochondrial enzyme activities and SOD2 deacetylation in a Sirt3-dependent manner. The results of western blot analysis showed that ZL006 increased the activation of AMPK-PGC-1α-Sirt3 pathway, and the beneficial effects of ZL006 was partially abolished by AMPK inhibitor and PGC-1α knockdown. Therefore, our present data showed that, by the AMPK-PGC-1α-Sirt3 pathway, ZL006 protects spinal cord neurons against ischemia through reducing mitochondrial oxidative stress to prevent apoptosis.

Interactions between Sirt1 and MAPKs regulate astrocyte activation induced by brain injury in vitro and in vivo

Background

Astrocyte activation is a hallmark of traumatic brain injury resulting in neurological dysfunction or death for an overproduction of inflammatory cytokines and glial scar formation. Both the silent mating type information (Sirt1) expression and mitogen-activated protein kinase (MAPK) signal pathway activation represent a promising therapeutic target for several models of neurodegenerative diseases. We investigated the potential effects of Sirt1 upregulation and MAPK pathway pharmacological inhibition on astrocyte activation in vitro and in vivo. Moreover, we attempted to confirm the underlying interactions between Sirt1 and MAPK pathways in astrocyte activation after brain injury.

Methods

The present study employs an interleukin-1β (IL-1β) stimulated primary cortical astrocyte model in vitro and a nigrostriatal pathway injury model in vivo to mimic the astrocyte activation induced by traumatic brain injury. The activation of GFAP, Sirt1, and MAPK pathways were detected by Western blot; astrocyte morphological hypertrophy was assessed using immunofluorescence staining; in order to explore the neuroprotective effect of regulation Sirt1 expression and MAPK pathway activation, the motor and neurological function tests were assessed after injury.

Results

GFAP level and morphological hypertrophy of astrocytes are elevated after injury in vitro or in vivo. Furthermore, the expressions of phosphorylated extracellular regulated protein kinases (p-ERK), phosphorylated c-Jun N-terminal kinase (p-JNK), and phosphorylated p38 activation (p-p38) are upregulated, but the Sirt1 expression is downregulated. Overexpression of Sirt1 significantly increases the p-ERK expression and reduces the p-JNK and p-p38 expressions. Inhibition of ERK, JNK, or p38 activation respectively with their inhibitors significantly elevated the Sirt1 expression and attenuated the astrocyte activation. Both the overproduction of Sirt1 and inhibition of ERK, JNK, or p38 activation can alleviate the astrocyte activation, thereby improving the neurobehavioral function according to the modified neurological severity scores (mNSS) and balance latency test.

Conclusions

Thus, Sirt1 plays a protective role against astrocyte activation, which may be associated with the regulation of the MAPK pathway activation induced by brain injury in vitro and in vivo.

Resveratrol pretreatment attenuates injury and promotes proliferation of neural stem cells following oxygen-glucose deprivation/reoxygenation by upregulating the expression of Nrf2, HO-1 and NQO1 in vitro

There is considerable interest in the use of drugs and other methods for protecting implanted neural stem cells (NSCs) from the adverse environment of injured tissue for successful cell therapy. Resveratrol can modify cardiac stem cells to enhance their survival and differentiation, however, its effect and the mechanism underlying its neuroprotective effect on NSCs following stroke remain to be fully elucidated. Nuclear factor erythroid 2-related factor 2 (Nrf-2) signaling is important in antioxidative stress, and the role of Nrf-2 signaling in the enhanced neuroprotection of NSCs by resveratrol following stroke also remains to be elucidated. In the present study, NSCs were pretreated with resveratrol prior to oxygen-glucose deprivation/reoxygenation (OGD/R) in vitro. The survival, apoptosis and proliferation of the NSCs were assessed using an MTT assay, Hoechst 33258 staining of nuclei and flow cytometry, respectively. In addition, the activity of superoxide dismutase (SOD), level of malondiadehyde (MDA) and content of glutathione (GSH) were determined. The protein expressions levels of Nrf-2, NAD(P)H:quinone oxidoreductase 1 (NQO-1), and heme oxygenase 1 (HO-1) were detected using western blot analysis. It was found that resveratrol markedly enhanced NSC survival and proliferation, decreased apoptosis and the levels of MDA, and increased the activity of SOD and content of GSH in a concentration-dependent manner following OGD/R injury in vitro. In addition, the protein expression levels of Nrf2, HO-1 and NQO1 were significantly upregulated. These findings suggested that resveratrol attenuated injury and promoted proliferation of the NSCs, at least in part, by upregulating the expression of Nrf2, HO-1 and NQO1 following OGD/R injury in vitro.

Neuroprotective Effect of Osthole on Neuron Synapses in an Alzheimer's Disease Cell Model via Upregulation of MicroRNA-9

Accumulation of β-amyloid peptide (Aβ) in the brain plays an important role in the pathogenesis of Alzheimer's disease (AD). It has been reported that osthole exerts its neuroprotective effect on neuronal synapses, but its exact mechanism is obscure. Recently, microRNAs have been demonstrated to play a crucial role in inducing synaptotoxicity by Aβ, implying that targeting microRNAs could be a therapeutic approach of AD. In the present study, we investigated the neuroprotective effects of osthole on a cell model of AD by transducing APP695 Swedish mutant (APP695swe, APP) into mouse cortical neurons and human SH-SY5Y cells. In this study, the cell counting kit CCK-8, apoptosis assay, immunofluorescence analysis, enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction, and Western blot assay were used. We found that osthole could enhance cell viability, prevent cell death, and reverse the reduction of synaptic proteins (synapsin-1, synaptophysin, and postsynaptic density-95) in APP-overexpressed cells, which was attributed to increases in microRNA-9 (miR-9) expression and subsequent decreases in CAMKK2 and p-AMPKα expressions. These results demonstrated that osthole plays a neuroprotective activity role in part through upregulating miR-9 in AD.

Regulation and role of ERK phosphorylation in glial cells following a nigrostriatal pathway injury

This study was undertaken to examine the function of extracellular signal-regulated kinase (ERK) signaling pathway on the proliferation and activation of microglia/macrophage and astrocytes after brain injury in mice. The result of Western blot showed that p-ERK was immediately activated after injury (<4h), but the duration was short (<4 days). According to immunofluorescence double staining, it was found that at 4 and 8h after injury, p-ERK was expressed in microglia/macrophages, and that more cells were co-expressed by p-ERK and IBA-1 (microglia/macrophage marker) at 8h; at days 1 and 4, p-ERK was expressed in astrocytes, and more cells were co-expressed by p-ERK and GFAP (astrocyte marker) at day 4. After injury, the mice were injected with U0126 (MAPK/ERK signaling pathway inhibitor) via the femoral vein. Compared with those injected with DMSO, the cell number co-expressed by p-ERK and IBA-1 or GFAP significantly decreased (P<0.05). The increase of microglia/macrophage and astrocyte caused by injury was remitted, and the positive cell number significantly decreased (P<0.05). Western blot showed that the expression quantity of IBA-1 and GFAP significantly decreased (P<0.05). Furthermore, the ERK signaling pathway was involved in the proliferation and activation of the two glial cells types and improved long-term neurobehavioral function after brain injury. Therefore, the exploration of the formation mechanism of glial scar after injury and further research on the therapeutic method of neural regeneration are essential.

MLIF Alleviates SH-SY5Y Neuroblastoma Injury Induced by Oxygen-Glucose Deprivation by Targeting Eukaryotic Translation Elongation Factor 1A2

Monocyte locomotion inhibitory factor (MLIF), a heat-stable pentapeptide, has been shown to exert potent anti-inflammatory effects in ischemic brain injury. In this study, we investigated the neuroprotective action of MLIF against oxygen-glucose deprivation (OGD)-induced injury in human neuroblastoma SH-SY5Y cells. MTT assay was used to assess cell viability, and flow cytometry assay and Hoechst staining were used to evaluate apoptosis. LDH assay was used to exam necrosis. The release of inflammatory cytokines was detected by ELISA. Levels of the apoptosis associated proteins were measured by western blot analysis. To identify the protein target of MLIF, pull-down assay and mass spectrometry were performed. We observed that MLIF enhanced cell survival and inhibited apoptosis and necrosis by inhibiting p-JNK, p53, c-caspase9 and c-caspase3 expression. In the microglia, OGD-induced secretion of inflammatory cytokines was markedly reduced in the presence of MLIF. Furthermore, we found that eukaryotic translation elongation factor 1A2 (eEF1A2) is a downstream target of MLIF. Knockdown eEF1A2 using short interfering RNA (siRNA) almost completely abrogated the anti-apoptotic effect of MLIF in SH-SY5Y cells subjected to OGD, with an associated decrease in cell survival and an increase in expression of p-JNK and p53. These results indicate that MLIF ameliorates OGD-induced SH-SY5Y neuroblastoma injury by inhibiting the p-JNK/p53 apoptotic signaling pathway via eEF1A2. Our findings suggest that eEF1A2 may be a new therapeutic target for ischemic brain injury.

Resveratrol Pretreatment Decreases Ischemic Injury and Improves Neurological Function Via Sonic Hedgehog Signaling After Stroke in Rats

Resveratrol has neuroprotective effects for ischemic cerebral stroke. However, its neuroprotective mechanism for stroke is less well understood. Beneficial actions of the activated Sonic hedgehog (Shh) signaling pathway in stroke, such as improving neurological function, promoting neurogenesis, anti-oxidative, anti-apoptotic, and pro-angiogenic effects, have been noted, but relatively little is known about the role of Shh signaling in resveratrol-reduced cerebral ischemic injury after stroke. The present study tests whether the Shh pathway mediates resveratrol to decrease cerebral ischemic injury and improve neurological function after stroke. We observed that resveratrol pretreatment significantly improved neurological function, decreased infarct volume, enhanced vitality, and reduced apoptosis of neurons in vivo and vitro after stroke. Meanwhile, expression levels of Shh, Ptc-1, Smo, and Gli-1 mRNAs were significantly upregulated and Gli-1 was relocated to the nucleus. Intriguingly, in vivo and in vitro inhibition of the Shh signaling pathway with cyclopamine, a Smo inhibitor, completely reversed the above effects of resveratrol. These results suggest that decreased cerebral ischemic injury and improved neurological function by resveratrol may be mediated by the Shh signaling pathway.

Osthole promotes neuronal differentiation and inhibits apoptosis via Wnt/β-catenin signaling in an Alzheimer's disease model

Neurogenesis is the process by which neural stem cells (NSCs) proliferate and differentiate into neurons. This is diminished in several neurodegenerative disorders such as Alzheimer's disease (AD), which is characterized by the deposition of amyloid (A)β peptides and neuronal loss. Stimulating NSCs to replace lost neurons is therefore a promising approach for AD treatment. Our previous study demonstrated that osthole modulates NSC proliferation and differentiation, and may reduce Aβ protein expression in nerve cells. Here we investigated the mechanism underlying the effects of osthole on NSCs. We found that osthole enhances NSC proliferation and neuronal differentiation while suppressing apoptosis, effects that were exerted via activation of Wnt/β-catenin signaling. These results provide evidence that osthole can potentially be used as a therapeutic agent in the treatment of AD and other neurodegenerative disorders.

Osthole confers neuroprotection against cortical stab wound injury and attenuates secondary brain injury

Background

Neuroendoscopy is an innovative technique for neurosurgery that can nonetheless result in traumatic brain injury. The accompanying neuroinflammation may lead to secondary tissue damage, which is the major cause of delayed neuronal death after surgery. The present study investigated the capacity of osthole to prevent secondary brain injury and the underlying mechanism of action in a mouse model of stab wound injury.

Methods

A mouse model of cortical stab wound injury was established by inserting a needle into the cerebral cortex for 20 min to mimic neuroendoscopy. Mice received an intraperitoneal injection of osthole 30 min after surgery and continued for 14 days. Neurological severity was evaluated 12 h and up to 21 days after the trauma. Brains were collected 3–21 days post-injury for histological analysis, immunocytochemistry, quantitative real-time PCR, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and enzyme-linked immunosorbent assays.

Results

Neurological function improved in mice treated with osthole and was accompanied by reduced brain water content and accelerated wound closure relative to untreated mice. Osthole treatment reduced the number of macrophages/microglia and peripheral infiltrating of neutrophils and lowered the level of the proinflammatory cytokines interleukin-6 and tumor necrosis factor α in the lesioned cortex. Osthole-treated mice had fewer TUNEL+ apoptotic neurons surrounding the lesion than controls, indicating increased neuronal survival.

Conclusions

Osthole reduced secondary brain damage by suppressing inflammation and apoptosis in a mouse model of stab wound injury. These results suggest a new strategy for promoting neuronal survival and function after neurosurgery to improve long-term patient outcome.

Cnidium monnieri: A Review of Traditional Uses, Phytochemical and Ethnopharmacological Properties

Cnidium monnieri (L.) Cuss., an annual plant of the Umbelliferae species is one of the most widely used traditional herbal medicines and its fruits have been used to treat a variety of diseases in China, Vietnam, and Japan. The aim of this review is to provide an up-to-date and comprehensive analysis of the botany, traditional uses, phytochemistry, pharmacology, toxicity and contraindication of Cnidium monnieri (L.) Cuss. and to provide future directions of research on this plant. To date, 350 compounds have been isolated and identified from Cnidium monnieri (L.) Cuss., including the main active constituent, coumarins. In vitro and in vivo studies suggest that osthole and other coumarin compounds possess wide range of pharmacological properties for the treatment of female genitals, male impotence, frigidity, skin-related diseases, and exhibit strong antipruritic, anti-allergic, antidermatophytic, antibacterial, antifungal, anti-osteoporotic effects. Although coumarins have been identified as the main active constituents responsible for the observed pharmacological effects, the molecular mechanisms of their actions are still unknown. Therefore, further studies are still required to reveal the structure-activity relationship of these active constituents. In addition, toxicological and clinical studies are also required to provide further data for pharmaceutical use.