Gastrodin Attenuates Lipopolysaccharide-Induced Inflammatory Response and Migration via the Notch-1 Signaling Pathway in Activated Microglia.

Microglia-mediated neuroinflammation is known to play a pivotal role in the pathogenesis of different neurological diseases. Gastrodin, a phenolic glucoside, has been reported to exert anti-inflammatory effects in activated microglia challenged with lipopolysaccharide (LPS); however, the underlying mechanism has remained obscure. The present study aimed to ascertain if Gastrodin would regulate the Notch signaling pathway involved in microglia activation. We show here that LPS increased the expression of various members of the Notch-1 pathway, including intracellular Notch receptor domain (NICD), recombining binding protein suppressor of hairless (RBP-Jκ) and transcription factor hairy and enhancer of split-1 (Hes-1) in microglia in postnatal rat brain and in BV-2 microglia. Remarkably, Gastrodin was found to markedly attenuate the expression of the above various biomarkers both in vivo and in vitro. Moreover, increased phosphorylation level of ERK, JNK and P38 induced by LPS was attenuated with pretreatment of Notch-1 signaling inhibitor, N-[N-(3,5-difluorophenacetyl)-1-alany1-Sphenyglycinet-butylester (DAPT) as well as Gastrodin. Gastrodin mimicked the effects of DAPT by inhibiting the LPS-induced expression of IL-1ß, IL-6, IL-23, TNF-α and NO. Moreover, lentivirus transfection mediated NICD overexpression inhibited the anti-inflammatory effects of Gastrodin. Furthermore, the activation of Notch-1 signaling promoted microglia migration and Gastrodin could inhibit the migration of activated BV-2 microglia by regulating the Notch-1 signaling pathway. In light of the above, our results indicate that Notch-1 signaling pathway is involved in the anti-inflammatory effects of Gastrodin against LPS-induced microglia activation. These findings provide a new biological target of Gastrodin for the treatment of neuroinflammatory disorders.

Gnaq Protects PC12 Cells from Oxidative Damage by Activation of Nrf2 and Inhibition of NF-kB.

Reactive oxygen species (ROS) are continuously produced as byproducts of aerobic metabolism. Oxidative stress (OS) plays an important role in the occurrence of several neurodegenerative diseases as well as aging because of the accumulation of ROS. Gnaq is a member of G protein α subunits. It has been reported that the expression level of Gnaq in the mouse forebrain cortex was significantly decreased with age in our previous study; therefore, we supposed that Gnaq contributes to attenuate the OS. In this study, we generated a Gnaq-overexpression cell using gene recombinant technique and lentivirus transfection technique in a neuron-like PC12 cell, and investigated whether Gnaq had antioxidant effects in PC12 cells treated with H2O2. The viability of cells, concentration of ROS, Nrf2 nuclear translocation, expression of antioxidant enzymes, activation of NF-κB and apoptosis were compared between Gnaq-PC12 cells and Vector-PC12 cells. Results showed that, compared with Vector-PC12 cells, the antioxidative ability of Gnaq-PC12 cells was significantly improved, while the ROS level in Gnaq-PC12 cells was significantly decreased. Nrf2 nuclear translocation was up-regulated and NF-κB nuclear translocation was down-regulated in Gnaq-PC12 cells after H2O2 treatment. The results suggest that Gnaq plays a crucial role in neuroprotection in PC12 cells. A possible mechanism for this would be that the overexpressed Gnaq enhances the antioxidative effect mediated by Nrf2 signal pathway and inhibits the cellular damaging effect through NF-κB signal pathway.

Transplantation of Nurr1-overexpressing neural stem cells and microglia for treating parkinsonian rats.

BACKGROUND: Neural stem cells (NSCs) transplantation is considered a promising treatment for Parkinson's disease. But most NSCs are differentiated into glial cells rather than neurons, and only a few of them survive after transplantation due to the inflammatory environment. METHODS: In this study, neural stem cells (NSCs) and microglial cells both forced with the Nurr1 gene were transplanted into the striatum of the rat model of PD. The results were evaluated through reverse transcription polymerase chain reaction (RT-PCR), Western blot, and immunofluorescence analysis. RESULTS: The behavioral abnormalities of PD rats were improved by combined transplantation of NSCs and microglia, both forced with Nurr1. The number of tyrosine hydroxylase+ cells in the striatum of PD rats increased, and the number of Iba1+ cells decreased compared with the other groups. Moreover, the dopamine neurons differentiated from grafted NSCs could still be detected in the striatum of PD rats after 5 months. CONCLUSIONS: The results suggested that transplantation of Nurr1-overexpressing NSCs and microglia could improve the inhospitable host brain environments, which will be  a new potential strategy for the cell replacement therapy in PD.

Gastrodin Ameliorates Motor Learning Deficits Through Preserving Cerebellar Long-Term Depression Pathways in Diabetic Rats.

Cognitive dysfunction is a very severe consequence of diabetes, but the underlying causes are still unclear. Recently, the cerebellum was reported to play an important role in learning and memory. Since long-term depression (LTD) is a primary cellular mechanism for cerebellar motor learning, we aimed to explore the role of cerebellar LTD pathways in diabetic rats and the therapeutic effect of gastrodin. Diabetes was induced by a single injection of streptozotocin into adult Sprague-Dawley rats. Motor learning ability was assessed by a beam walk test. Pathological changes of the cerebellum were assessed by Hematoxylin-Eosin (HE) and Nissl staining. Cellular apoptosis was assessed by anti-caspase-3 immunostaining. Protein expression levels of LTD pathway-related factors, including GluR2, protein kinase C (PKC), NR2A, and nNOS, in the cerebellar cortex were evaluated by western blotting and double immunofluorescence. The NO concentration was measured. The cellular degeneration and the apoptosis of Purkinje cells were evident in the cerebellum of diabetic rats. Protein expression levels of GluR2 (NC9W: 1.26 ± 0.12; DM9W + S: 0.81 ± 0.07), PKC (NC9W: 1.66 ± 0.10; DM9W + S: 0.58 ± 0.19), NR2A (NC9W: 1.40 ± 0.05; DM9W + S: 0.63 ± 0.06), nNOS (NC9W: 1.26 ± 0.12; DM9W + S: 0.68 ± 0.04), and NO (NC9W: 135.61 ± 31.91; DM9W + S: 64.06 ± 24.01) in the cerebellum were significantly decreased in diabetic rats. Following gastrodin intervention, the outcome of motor learning ability was significantly improved (NC9W: 6.70 ± 3.31; DM9W + S: 20.47 ± 9.43; DM9W + G: 16.04 ± 7.10). In addition, degeneration and apoptosis were ameliorated, and this was coupled with the elevation of the protein expression of the abovementioned biomarkers. Arising from the above, we concluded that gastrodin may contribute to the improvement of motor learning by protecting the LTD pathways in Purkinje cells.

Nurr1 promotes neurogenesis of dopaminergic neuron and represses inflammatory factors in the transwell coculture system of neural stem cells and microglia.

INTRODUCTION: Neural stem cells (NSCs) are the most promising cells for cell replacement therapy for Parkinson's disease (PD). However, a majority of the transplanted NSCs differentiated into glial cells, thereby limiting the clinical application. Previous studies indicated that chronic neuroinflammation plays a vital role in the degeneration of midbrain DA (mDA) neurons, which suggested the developing potential of therapies for PD by targeting the inflammatory processes. Thus, Nurr1 (nuclear receptor-related factor 1), a transcription factor, has been referred to play a pivotal role in both the differentiation of dopaminergic neurons in embryonic stages and the maintenance of the dopaminergic phenotype throughout life. AIM: This study investigated the effect of Nurr1 on neuroinflammation and differentiation of NSCs cocultured with primary microglia in the transwell coculture system. RESULTS: The results showed that Nurr1 exerted anti-inflammatory effects and promoted the differentiation of NSCs into dopaminergic neurons. CONCLUSIONS: The results suggested that Nurr1 protects dopaminergic neurons from neuroinflammation insults by limiting the production of neurotoxic mediators by microglia and maintain the survival of transplanted NSCs. These phenomena provided a new theoretical and experimental foundation for the transplantation of Nurr1-overexpressed NSCs as a potential treatment of PD.

Completely Recyclable Monomers and Polycarbonate: Approach to Sustainable Polymers.

It is of great significance to depolymerize used or waste polymers to recover the starting monomers suitable for repolymerization reactions that reform recycled materials no different from the virgin polymer. Herein, we report a novel recyclable plastic: degradable polycarbonate synthesized by dinuclear chromium-complex-mediated copolymerization of CO2 with 1-benzyloxycarbonyl-3,4-epoxy pyrrolidine, a meso-epoxide. Notably, the novel polycarbonate with more than 99 % carbonate linkages could be recycled back into the epoxide monomer in quantitative yield under mild reaction conditions. Remarkably, the copolymerization/depolymerization processes can be achieved by the ON/OFF reversible temperature switch, and recycled several times without any change in the epoxide monomer and copolymer. These characteristics accord well with the concept of perfectly sustainable polymers.

Gastrodin attenuation of the inflammatory response in H9c2 cardiomyocytes involves inhibition of NF-κB and MAPKs activation via the phosphatidylinositol 3-kinase signaling.

The phenolic glucoside gastrodin, a main constituent of a Chinese traditional herbal medicine, has been known to display several biological and pharmacological properties. However, the role and precise molecular mechanisms explaining how gastrodin suppresses the inflammatory response in septic cardiac dysfunction are unknown. To study this, rat H9c2 cardiomyocytes were treated with gastrodin and/or lipopolysaccharide (LPS). Our results showed that gastrodin treatment strongly suppressed nuclear factor-κB (NF-κB) and mitogen-activated protein kinases (MAPKs) family activation and upregulation of the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in LPS-stimulated H9c2 cardiomyocytes. Simultaneously, gastrodin obviously upregulated the phosphatidylinositol 3-kinase (PI3-K)/Akt signaling in a dose-dependent manner. However, wortmannin, a specific PI3-K inhibitor, blocked the inhibitory effects of gastrodin on LPS-stimulated H9c2 cardiomyocytes. Furthermore, PI3-K/Akt inhibition partially abolished the inhibitory effects of gastrodin on the phosphorylation of inhibitor κB-α (IκB-α), extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal protein kinase (JNK), and p38 mitogen-activated protein kinase (p38 MAPK), and activity of NF-κB. Here we report activation of the PI3-K/Akt signaling by gastrodin and that inhibition of this pathway reverses the inhibitory effects of gastrodin on NF-κB and MAPKs activation in H9c2 cardiomyocytes.

[Resveratrol reduces inflammatory cytokines via inhibiting nuclear factor-κB and mitogen-activated protein kinase signal pathway in a rabbit atherosclerosis model].

OBJECTIVE: Inflammation serves as the initial pathologic step of cardiovascular diseases including atherosclerosis. Resveratrol possesses many pharmacological properties including antioxidant, cardioprotective and anti-cancer effects. In this study, we investigate the anti-inflammatory effect and mechanisms of resveratrol in an atherosclerotic rabbit model. METHODS: Rabbit were assigned to six groups (n = 10 each): control, high fat diet group, resveratrol low, medium and high dose groups, resveratrol pretreatment group. The serum tumor necrosis factor-α (TNF- α), interleukin-6 (IL-6) and interleukin-1ß (IL-1ß) were analyzed by Enzyme-linked immuno sorbent assay(ELISA). Phosphorylation levels of mitogen-activated protein kinases (MAPKs) cascades and NF-κB were determined by Western blot. RESULTS: Compared with the control group, the expression of serum inflammatory factors IL-1ß, IL-6, TNF-α were increased in high-fat group (all P < 0.05). Compared with high-fat group, the expressions of IL-6, IL-1ß, TNF-α were significantly reduced in resveratrol low, medium, high dose groups and resveratrol pretreatment group (all P < 0.01), and this effect is dose-dependent. In addition, the NF-κB, p38MAPK, JNK, ERK1/2 protein phosphorylation in high-fat group were significantly upregulated compared with control group (P < 0.05), which (except ERK1/2 phosphorylation level) were significantly downregulated in resveratrol treatment group and resveratrol pretreatment group. CONCLUSION: This study indicates that resveratrol reduces serum inflammatory cytokines in this atherosclerotic rabbit model via down-regulation phosphorylation of NF-κB, and MAPKs signaling, which might serve as the anti-inflammatory molecular basis of resveratrol.

Resveratrol inhibits inflammatory responses via the mammalian target of rapamycin signaling pathway in cultured LPS-stimulated microglial cells.

BACKGROUND: Resveratrol have been known to possess many pharmacological properties including antioxidant, cardioprotective and anticancer effects. Although current studies indicate that resveratrol produces neuroprotection against neurological disorders, the precise mechanisms for its beneficial effects are still not fully understood. We investigate the effect of anti-inflammatory and mechamisms of resveratrol by using lipopolysaccharide (LPS)-stimulated murine microglial BV-2 cells. METHODOLOGY/PRINCIPAL FINDINGS: BV-2 cells were treated with resveratrol (25, 50, and 100 µM) and/or LPS (1 µg/ml). Nitric oxide (NO) and prostaglandin E2 (PGE2) were measured by Griess reagent and ELISA. The mRNA and protein levels of proinflammatory proteins and cytokines were analysed by RT-PCR and double immunofluorescence labeling, respectively. Phosphorylation levels of PTEN (phosphatase and tensin homolog deleted on chromosome 10), Akt, mammalian target of rapamycin (mTOR), mitogen-activated protein kinases (MAPKs) cascades, inhibitor κB-α (IκB-α) and cyclic AMP-responsive element-binding protein (CREB) were measured by western blot. Resveratrol significantly attenuated the LPS-induced expression of NO, PGE2, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß) and nuclear factor-κB (NF-κB) in BV-2 cells. Resveratrol increased PTEN, Akt and mTOR phosphorylation in a dose-dependent manner or a time-dependent manner. Rapamycin (10 nM), a specific mTOR inhibitor, blocked the effects of resveratrol on LPS-induced microglial activation. In addition, mTOR inhibition partially abolished the inhibitory effect of resveratrol on the phosphorylation of IκB-α, CREB, extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal protein kinase (JNK), and p38 mitogen-activated protein kinase (p38 MAPK). CONCLUSION AND IMPLICATIONS: This study indicates that resveratrol inhibited LPS-induced proinflammatory enzymes and proinflammatory cytokines via down-regulation phosphorylation of NF-κB, CREB and MAPKs family in a mTOR-dependent manner. These findings reveal, in part, the molecular basis underlying the anti-inflammatory properties of resveratrol.