Acetylated tau exacerbates learning and memory impairment by disturbing with mitochondrial homeostasis.

Increased tau acetylation at K274 and K281 has been observed in the brains of Alzheimer's disease (AD) patients and animal models, and mitochondrial dysfunction are noticeable and early features of AD. However, the effect of acetylated tau on mitochondria has been unclear until now. Here, we constructed three type of tau forms, acetylated tau mutant by mutating its K274/K281 into Glutamine (TauKQ) to mimic disease-associated lysine acetylation, the non-acetylation tau mutant by mutating its K274/K281 into Arginine (TauKR) and the wild-type human full-length tau (TauWT). By overexpression of these tau forms in vivo and in vitro, we found that, TauKQ induced more severe cognitive deficits with neuronal loss, dendritic plasticity damage and mitochondrial dysfunctions than TauWT. Unlike TauWT induced mitochondria fusion, TauKQ not only induced mitochondria fission by decreasing mitofusion proteins, but also inhibited mitochondrial biogenesis via reduction of PGC-1a/Nrf1/Tfam levels. TauKR had no significant difference in the cognitive and mitochondrial abnormalities compared with TauWT. Treatment with BGP-15 rescued impaired learning and memory by attenuation of mitochondrial dysfunction, neuronal loss and dendritic complexity damage, which caused by TauKQ. Our data suggested that, acetylation at K274/281 was an important post translational modification site for tau neurotoxicity, and BGP-15 is a potential therapeutic drug for AD.

Ethanolic extract of fructus Alpinia oxyphylla protects against 6-hydroxydopamine-induced damage of PC12 cells in vitro and dopaminergic neurons in zebrafish.

In an attempt to understand the neuroprotective effect of Fructus Alpinia oxyphylla (AOE) and to elucidate its underlying mechanism of action, the ethanolic extract of AOE was investigated using zebrafish and PC12 cell models. AOE prevented and restored 6-hydroxydopamine (6-OHDA)-induced dopaminergic (DA) neuron degeneration and attenuated a deficit of locomotor activity in a zebrafish (Danio rerio) model of Parkinson's disease (PD). Treatment with AOE increased the viability of 6-OHDA-treated PC12 cells in vitro in a dose-dependent manner by attenuating cellular apoptosis. However, protocatechuic acid (PCA) and chrysin, two known polyphenol components of AOE, could not reproduce the neuroprotective activity of AOE in the PD zebrafish or PC12 cell models. A mechanistic study found that the protective effect of AOE against 6-OHDA-induced neuronal injury involved anti-inflammatory action (down-regulation of gene expression of IL-1ß and TNF-α) and anti-oxidative action (inhibition of NO production and iNOS expression in PC12 cells). Moreover, the PI3K-AKT pathway might be part of the mechanism of neuroprotection of AOE. The results of this research are expected to provide a scientific rationale for the use of AOE in the treatment of PD. However, it is important that the active components that contribute to the neuroprotective action of AOE are identified and characterized.

dl-3n-Butylphthalide promotes angiogenesis via the extracellular signal-regulated kinase 1/2 and phosphatidylinositol 3-kinase/Akt-endothelial nitric oxide synthase signaling pathways.

We have previously demonstrated that dl-3n-butylphthalide (NBP) has a potential angiogenic activity. In this study, we investigated the angiogenic effect of NBP and the molecular mechanisms underlying NBP-mediated angiogenesis. Zebrafish embryos and human umbilical vein endothelial cells were treated with various doses of NBP and several signaling pathway inhibitors. NBP induced ectopic subintestinal vessel production in zebrafish embryos and induced invasion, migration, and endothelial cell tube formation of human umbilical vein endothelial cells in a dose-dependent manner. These NBP-induced angiogenic effects were partially suppressed by SU5402, a fibroblast growth factor receptor 1 inhibitor; U0126, an extracellular signal-regulated kinase 1/2 (ERK1/2) inhibitor; LY294002, a phosphatidylinositol 3-kinase inhibitor; 1L6-hydroxymethyl-chiro-inositol-2-(R)-2-O-methyl-3-O-octadecyl-sn-glycerocarbonate, an Akt inhibitor; cavtratin, an endothelial nitric oxide synthase (eNOS) inhibitor and completely inhibited by a combination of U0126 and LY294002. NBP enhanced phosphorylation of ERK1/2 and fibroblast growth factor receptor 2 expression, which were inhibited by U0126. NBP increased the phosphorylation of Akt and eNOS at serine 1177, which was blocked by LY294002. NBP-stimulated nitric oxide production, which was reduced by LY294002. Our data demonstrated that (1) NBP promoted angiogenesis and (2) the angiogenic effects of NBP were mediated by the ERK1/2 and phosphatidylinositol 3-kinase/Akt-eNOS signaling pathways. Our findings suggest that NBP could be a novel agent for therapeutic angiogenesis in ischemic diseases.

From omics to drug metabolism and high content screen of natural product in zebrafish: a new model for discovery of neuroactive compound.

The zebrafish (Danio rerio) has recently become a common model in the fields of genetics, environmental science, toxicology, and especially drug screening. Zebrafish has emerged as a biomedically relevant model for in vivo high content drug screening and the simultaneous determination of multiple efficacy parameters, including behaviour, selectivity, and toxicity in the content of the whole organism. A zebrafish behavioural assay has been demonstrated as a novel, rapid, and high-throughput approach to the discovery of neuroactive, psychoactive, and memory-modulating compounds. Recent studies found a functional similarity of drug metabolism systems in zebrafish and mammals, providing a clue with why some compounds are active in zebrafish in vivo but not in vitro, as well as providing grounds for the rationales supporting the use of a zebrafish screen to identify prodrugs. Here, we discuss the advantages of the zebrafish model for evaluating drug metabolism and the mode of pharmacological action with the emerging omics approaches. Why this model is suitable for identifying lead compounds from natural products for therapy of disorders with multifactorial etiopathogenesis and imbalance of angiogenesis, such as Parkinson's disease, epilepsy, cardiotoxicity, cerebral hemorrhage, dyslipidemia, and hyperlipidemia, is addressed.

Protective, antioxidative and antiapoptotic effects of 2-methoxy-6-acetyl-7-methyljuglone from Polygonum cuspidatum in PC12 cells.

Much correlative evidence indicates that the oxidative modification of protein by reactive oxygen species (ROS) is involved in normal aging as well as the pathogenesis of neurodegenerative diseases such as Alzheimer's disease. In this study, we explored the antioxidative and neuroprotective effects of a naphthoquinone, 2-methoxy-6-acetyl-7-methyljuglone (MAM), purified from the dried rhizome of POLYGONUM CUSPIDATUM (Chinese name Hu-Zhang). Pretreatments with MAM (24 h) were investigated for their protective effects against apoptosis induced by the oxidizing agent TERT-butyl hydroperoxide ( T-BHP) in PC12 cells. The results indicated that MAM pretreatments could effectively protect PC12 cells against cytotoxicity induced by T-BHP in a dose-dependent manner. Cell viability was determined by both MTT and LDH assays. Increasing concentrations of MAM enhanced cell viability significantly and completely prevented cell death induced by T-BHP at 2.5 µM. The corresponding extracellular lactate dehydrogenase (LDH) levels were also attenuated significantly by various concentrations of MAM. In addition, it was found that the antioxidative effect of MAM was stronger than those of resveratrol and lipoic acid. The antiapoptotic property of MAM was further investigated with Hoechst 33342 nuclear staining and TUNEL assay. Pretreatments of MAM were able to prevent the T-BHP-induced nucleus fragmentation and accumulation of apoptotic bodies (commonly accepted as markers of apoptosis) inside the cells in a dose-dependent manner. T-BHP induced the phosphorylation of ERK 1/2, JNK and p38 MAPK, which were all impeded by pretreatments with MAM, indicating that MAM may act as a potent antioxidant which significantly interferes with the MAPK apoptotic cascades, probably rescuing cells by inhibiting the death pathways.

[The inhibitory effect of luteolin on inflammation in LPS-induced microglia].

OBJECTIVE: To study the inhibitory effect of Luteolin on LPS-induced BV-2 cell. METHODS: BV-2 cells were treated with LPS (0.1 microg/mL) for inflammation model; MTT assay was used to detect the viability of BV-2 cells; Nitric oxide (NO) was detected by the method of nitric acid reductase assay; Induce type II nitric oxide synthase (iNOS) enzyme activity was determined by type of nitric oxide synthase assay;TLR4 protein expression was examined by the Western Blot analysis. RESULTS: Luteolin significantly decreased the NO production and TLR4 protein expression as well as iNOS activity in LPS-activated microglial cell. CONCLUSION: LPS induced activation of microglia lead to inflammatory response and its mechanism may be related to inhibiting TLR4 signaling pathway.

Luteolin delays photoreceptor degeneration in a mouse model of retinitis pigmentosa.

Luteolin is neuroprotective for retinal ganglion cells and retinal pigment epithelial cells after oxidative injury, whereby it can inhibit microglial neurotoxicity. Therefore, luteolin holds the potential to be useful for treatment of retinal diseases. The purpose of this study was to investigate whether luteolin exhibits neuroprotective effects on rod cells in rd10 mice, a slow photoreceptor-degenerative model of retinitis pigmentosa. Luteolin (100 mg/kg) intraperitoneally injected daily from postnatal day 14 (P14) to P25 significantly enhanced the visual performance and retinal light responses of rd10 mice at P25. Moreover, it increased the survival of photoreceptors and improved retinal structure. Mechanistically, luteolin treatment attenuated increases in reactive oxygen species, photoreceptor apoptosis, and reactive gliosis; increased mRNA levels of anti-inflammatory cytokines while lowering that of pro-inflammatory and chemoattractant cytokines; and lowered the ratio of phospho-JNK/JNK. Application of the JNK inhibitor SP600125 exerted a similar protective effect to luteolin, suggesting that luteolin delays photoreceptor degeneration and functional deterioration in rd10 mice through regulation of retinal oxidation and inflammation by inhibiting the JNK pathway. Therefore, luteolin may be useful as a supplementary treatment for retinitis pigmentosa. This study was approved by the Qualified Ethics Committee of Jinan University, China (approval No. IACUC-20181217-02) on December 17, 2018.

Dextran sulfate sodium-induced colitis and ginseng intervention altered oral pharmacokinetics of cyclosporine A in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Application of cyclosporine A (CsA) as a rescue treatment in acute severe ulcerative colitis (UC) is limited by its narrow therapeutic window and great interpatient variability. As a substrate of cytochrome P450 3A enzyme (CYP3A) and P-glycoprotein (P-gp), the oral pharmacokinetics of CsA is susceptible to disease status and concomitant medications. Combined treatment with ginseng, a famous medicinal herb frequently prescribed for ameliorating abnormal immune response in many diseases including UC, showed immunologic safety in CsA-based immunosuppression. AIM OF THE STUDY: Since the therapeutic levels of CsA can be achieved within 24 h, this study first assessed the impact of acute colitis and ginseng intervention on the single oral dose pharmacokinetics of CsA and explored the underlying mechanisms in dextran sulfate sodium (DSS)-induced colitis rats and Caco-2 cells. MATERIALS AND METHODS: Rats received drinking water (normal group), 5% DSS (UC group), or 5% DSS plus daily oral ginseng extract (GS+UC group). On day 7, GS+UC group only received an oral dose of CsA (5 mg/kg), while animals of normal or UC group received an oral, intravenous (1.25 mg/kg), or intraperitoneal dose of CsA (1.25 mg/kg), respectively. Blood, liver/intestine tissues and fecal samples were collected for determining CsA and main hydroxylated metabolite HO-CsA or measuring hepatic/intestinal CYP3A activity. Caco-2 cells were incubated with gut microbial culture supernatant (CS) of different groups or ginseng (decoction or polysaccharides), and then CYP3A, P-gp and tight junction (TJ) proteins were determined. RESULTS: Oral CsA exhibited enhanced absorption, systemic exposure and tissue accumulation, and lower fecal excretion, while intravenous or intraperitoneal CsA showed lower systemic exposure and enhanced distribution, in colitis rats. Diminished intestinal and hepatic P-gp expression well explained the changes with DSS-induced colitis. Moreover, blood exposures of HO-CsA in both normal and colitis after oral dosing were significantly higher than intravenous/intraperitoneal dosing, supporting the dominant role of intestinal first-pass metabolism. Interestingly, colitis reduced CYP3A expression in intestine and liver but only potentiated intestinal CYP3A activity, causing higher oral systemic exposure of HO-CsA. Oral ginseng mitigated colitis-induced down-regulation of CYP3A and P-gp expression, facilitated HO-CsA production, biliary excretion and colonic sequestration of CsA, while not affected CsA oral systemic exposure. In Caco-2 cells, gut microbial CS from both colitis and GS+UC group diminished P-gp function, while ginseng polysaccharides directly affected ZO-1 distribution and suppressed TJ proteins expression, explaining unaltered oral CsA systemic exposure. CONCLUSIONS: DSS-induced colitis significantly altered oral CsA disposition through regulating intestinal and hepatic P-gp and CYP3A. One-week ginseng treatment enhanced colonic accumulation while not altered the systemic exposure of CsA after single oral dosing, indicating pharmacokinetic compatibility between the two medications.

Resveratrol derivative, trans-3,5,4'-trimethoxystilbene, exerts antiangiogenic and vascular-disrupting effects in zebrafish through the downregulation of VEGFR2 and cell-cycle modulation.

Angiogenesis plays an important role in the development of neoplastic diseases such as cancer. Resveratrol and its derivatives exert antiangiogenic effects, but the mechanisms of their actions remain unclear. The aim of this study was to evaluate the antiangiogenic activity of resveratrol and its derivative trans-3,5,4'-trimethoxystilbene in vitro using human umbilical vein endothelial cells (HUVECs) and in vivo using transgenic zebrafish, and to clarify their mechanisms of action in zebrafish by gene expression analysis of the vascular endothelial growth factor (VEGF) receptor (VEGFR2/KDR) and cell-cycle analysis. trans-3,5,4'-Trimethoxystilbene showed significantly more potent antiangiogenic activity than that of resveratrol in both assays. In zebrafish, trans-3,5,4'-trimethoxystilbene caused intersegmental vessel regression and downregulated VEGFR2 mRNA expression. Trans-3,5,4'-trimethoxystilbene also induced G2/M cell-cycle arrest, most specifically in endothelial cells of zebrafish embryos. We propose that the antiangiogenic and vascular-targeting activities of trans-3,5,4'-trimethoxystilbene result from the downregulation of VEGFR2 expression and cell-cycle arrest at G2/M phase.

[Efficacy of gemcitabine combined with erlotinib in patients with advanced pancreatic cancer].

OBJECTIVE: To evaluate the efficacy,clinical benefits and toxicities of gemcitabine combined with erlotinib for advanced pancreatic cancer. METHOD: Clinical data of 20 patients with advanced pancreatic cancer treated with gemcitabine 1000 mg/m2 on day 1 and day 8 (repeated every 21 days) plus erlotinib 100-150 mg/d at Peking Union Medical College Hospital was reviewed retrospectively. RESULTS: No patient achieved complete remission or partial remission, 11 patients (55%) had stable disease, and 9 patients (45%) experienced disease progression. The disease control rate was 55%, and clinical benefit rate was 30%. The median progression free survival was 4.0 months, and the median overall survival was 8 months. The total incidence of hematologic toxicity was 70%, including 15% of grade 3-4 leucopenia and 5% of grade 3-4 thrombocytopenia. Eleven patients (55%) had rash, which were all grade 1-2. One patient had grade 2 diarrhea and five had grade 1 transaminase elevation. No chemotherapy-related death occurred. CONCLUSIONS: Gemcitabine combined with erlotinib is an effective regimen for pancreatic cancer with good clinical tolerance. The most common adverse events are hematologic toxicities and rash.

Andrographolide derivative ameliorates dextran sulfate sodium-induced experimental colitis in mice.

The therapeutic efficacy of immunosuppressive agents has been intensively studied for colitis management. We synthesized a series of andrographolide derivatives and reported their structure-activity-relationship and anti-inflammatory activity in our previous studies. Among these derivatives, compound 3b exhibited the most potent immunosuppressive activity. In the present study, we assessed the efficacy of 3b in dextran sulfate sodium (DSS)-induced model of acute colitis. Compound 3b was administered intragastrically. The therapeutic effect of 3b was evaluated using disease score and immune cell infiltration. The effect of 3b on Toll-like receptor 4/NF-κB and ß-catenin signaling was primarily determined by using immunohistochemistry staining and quantitative real-time PCR. The crosstalk between NF-κB and ß-catenin signaling was then assessed in HCT-116 cells. Treatment with 3b significantly downregulated the disease activity index and suppressed the histologic evidence of inflammation in DSS-induced model of acute colitis. Compound 3b inhibited proinflammatory cytokine expression at both the serum and transcription levels. Treatment with 3b also upregulated the number of PCNA-positive and goblet cells in the intestinal crypt and the intestinal expression of mRNA levels of ß-catenin target genes. ß-Catenin level regulation affected the antiinflammation and anti-apoptotic activities of 3b. This study demonstrated that 3b, a novel andrographolide derivative, suppressed inflammation and significantly reversed colitis pathology. The outcome of colitis treatment with an immunosuppressive agent depends upon the intestinal expression and mutation status of ß-catenin.

Triangeliphthalides A-D: bioactive phthalide trimers with new skeletons from Angelica sinensis and their production mechanism.

Triangeliphthalides A-D (1-4), four novel phthalide trimers with two new linkage styles, were isolated from Angelica sinensis, together with two related phthalide dimers (5-6). Their structures including absolute configurations were determined. The production mechanism of phthalide polymers was proposed, and their bioactivities were also evaluated.

RFLP analysis for mitochondrial genome of CMS-rice.

Restriction fragment length polymorphism (RFLP) was used to analyze mitochondrial (mt) genome of cytoplasmic male sterility (CMS) rice. Differences were observed among mitochondrial genomes of the sterile line (A) and maintain line (B) of nine types of CMS rice; Mitochondrial genomic differences were also detected between A and B in many functional gene regions. Even the materials with the same nucleic background have differences in their mtDNA. This provides molecular evidence for the cytoplasmic heterogeneity and the CMS mechanism research.

[Preliminary proteomics analysis of the total proteins of HL Type cytoplasmic male sterility rice anther].

The proteins of HL type cytoplasmic male sterility rice anther of YTA (CMS) and YTB (maintenance line) were separated by two-dimensional electrophoresis with immobilized ph (3-10 non-linear) gradients as the first dimension and SDS-PAGE as the second. The silver-stained proteins spots were analyzed using Image Master 2D software, there were about 1800 detectable spots on each 2D-gel, and about 85 spots were differential expressed. With direct MALDI-TOF mass spectrometry analysis and protein database searching, 9 protein spots out of 16 were identified. Among those proteins, there were Putative nucleic acid binding protein, glucose-1-phosphate adenylyltransferase (ADP-glucose pyrophosphorylase, AGPase) (EC: 2.7.7.27) large chain, UDP-glucuronic acid decarboxylase, putative calcium-binding protein annexin, putative acetyl-CoA synthetase and putative lipoamide dehydrogenase etc. They were closely associated with metabolism, protein biosynthesis, transcription, signal transduction and so on, all of which are cell activities that are essential to pollen development. Some of the identified proteins, i.e. AGPase, putative lipoamide dehydrogenase and putative acetyl-CoA synthetase were deeply discussed on the relationship to CMS. AGPase catalyzes a very important step in the biosynthesis of alpha 1,4-glucans (glycogen or starch) in bacteria and plants: synthesis of the activated glucosyl donor, ADP-glucose, from glucose-1-phosphate and ATP. The lack of the AGPase in male sterile line might directly result in the reduction of starch, and the synthesis of starch was the most important processes during the development of pollen. In present research, the descent or reduction of putative lipoamide dehydrogenase and putative acetyl-CoA synthetase seemed involved in pollen sterility in rice. The degeneration and formation of various tissues during pollen development may impose high demands for energy and key biosynthetic intermediates. Under such conditions, the TCA cycle needs to operate fully, because the TCA cycle is an important source for many intermediates required for biosynthetic pathways, in addition to performing an oxidative, energy-producing role. Thus, it seemed reasonable to infer that the decrease of putative lipoamide dehydrogenase and putative acetyl-CoA synthetase in anther might prevent the conversion of pyruvate into acetyl-CoA, and as a result, the TCA cycle could no longer operate at a sufficient rate to meet all requirements in anther cells, leading to pollen sterility. This study gave new insights into the mechanism of CMS in rice and demonstrated the power of the proteomic approach in plant biology studies.

No synergism between bis(propyl)-cognitin and rasagiline on protecting dopaminergic neurons in Parkinson's disease mice.

Rasagiline, a monoamine oxidase-B inhibitor, and bis(propyl)-cognitin (B3C), a novel dimer are reported to be neuroprotective. Herein, the synergistical neuroprotection produced by rasagiline and B3C was investigated in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mice of Parkinsonism. By using neurobehavioural tests, high-performance liquid chromatography and western blot assay, we showed that B3C at 0.3 mg/kg, rasagiline at 0.02 mg/kg, as well as co-treatment with B3C and rasagiline prevented MPTP-induced behavioural abnormities, increased the concentrations of dopamine and its metabolites in the striatum, and up-regulated the expression of tyrosine hydroxylase in the substantia nigra. However, the neuroprotective effects of co-treatment were not significantly improved when compared with those of B3C or rasagiline alone. Collectively, we have demonstrated that B3C at 0.3 mg/kg and rasagline at 0.02 mg/kg could not produce synergistic neuroprotective effects.

[Genetic polymorphism of bluegrass cultivars detected by RAPDs].

Kentucky bluegrass (Poa pratensis L.) is a hardy, persistent forage and turf grass adapted to a wide range of soils and climates. Its ever-increasing adoption in highly cared-for sports fields has attracted the attention of many seed companies. However in the past, the breeding of elite varieties was often hampered by the extreme complexity of the genome. The polymorphism is important for broading the genetic basis and may be exploited for application of heterosis. The genetic relationship of 16 bluegrass cultivars, including 15 accessions Kentucky bluegrass cultivars and 1 entries Canada bluegrass (Poa compressa L.) cultivar from different breeding company were analyzed using 25 RAPD markers. 25 RAPD primers generated 218 bands, of which 196 bands (89.91%) were polymorphism. It showed that the Canada Bluegrass was separated from other Kentucky Bluegrass and genetic polymorphism in the Kentucky Bluegrass cultivars was low, the genetic similarity among the cultivars fell between 66%-98%. Dendrogram obtained using these molecular markers were partly in agreement with their separated morphologic character. Cultivars from the same company were not clustered in one group.

Pharmacokinetic Study and Optimal Formulation of New Anti-Parkinson Natural Compound Schisantherin A.

Our recent studies showed that schisantherin A (StA) is a promising candidate for PD treatment, but the pharmacokinetic profile of StA is largely unknown. The effects of different formulations on the pharmacokinetics and bioavailability of StA were investigated by HPLC equipped with a vacuum degasser, a quaternary pump, a manual sampler, and an ultraviolet detector. The absolute bioavailability of StA in nanoemulsion formulation was significantly increased from 4.3% to 47.3%. To the best of our knowledge, this is the first report of absolute bioavailability for StA in rats and successful increase of bioavailability of StA by nanoemulsion formulation. The pharmacokinetic profiles of StA could be significantly improved by a safe nanoemulsion formulation. This study provides a successful example of advanced delivery system for improving the bioavailability of potential central nervous system (CNS) drug candidate with poor solubility. This novel approach could be an effective alternative solution to overcome the shortcomings of conventional poor drug delivery of CNS drugs. The results of present study not only indicate that StA has potential to be developed as a promising oral therapeutic agent for the management of PD but also shed light on novel way to improve bioavailability of PD drugs.

Discovery of novel anti-parkinsonian effect of schisantherin A in in vitro and in vivo.

Dibenzocyclooctadiene lignans represent a unique group of natural chemical structures, are considered as protectants against neuronal cell death and cognitive impairment in neurological disorders. Among the family of dibenzocyclooctadiene lignan analogs from the fruit of Schisandra chinensis (Turcz.) Baill, neuroprotective potential of schisantherin A (StA) has not yet been characterized. In this study, 1-methyl-4-phenylpyridinium ion (MPP(+))-incubated SH-SY5Y cells and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice were used to study the neuroprotection of StA. Pretreatment with StA significantly inhibited MPP(+)-induced cytotoxicity in SH-SY5Y cells. Moreover, StA conferred significant protection against MPTP-induced loss of TH-positive dopaminergic neurons in a Parkinson's disease (PD) mice model. Structure activity relationship analysis suggested that methylenedioxy, benzoyloxy and methoxyl groups, in the dibenzocyclooctadiene lignan of StA, were probably functionally important to its neuroprotective activity. In addition, Western blotting analysis demonstrated that StA exhibited neuroprotection against MPP(+) through the regulation of two distinct pathways including increasing CREB-mediated Bcl-2 expression and activating PI3K/Akt survival signaling suggesting that StA might be a promising neuroprotective agent for the prevention of PD.

A Potent Multi-functional Neuroprotective Derivative of Tetramethylpyrazine.

Neurodegenerative disorders are one of the leading causes of death among the elderly. Therapeutic approaches with a single target have proven unsuccessful in treating these diseases. Structural combination of multi-functional compounds may lead to a molecule with multiple properties. In this study, we designed and synthesized T-006, a novel analog derived from two multi-functional neuroprotective chemicals, tetramethylpyrazine and J147. The methoxyphenyl group of J147 was replaced by tetramethylpyrazine. Bioactivity evaluation showed that T-006 at very low concentrations had multi-functional neuroprotective effects including rescuing iodoacetic acid-induced neuronal loss, preventing oxidative stress-induced neurotoxicity and reducing glutamate-induced excitotoxicity in vitro. Most importantly, T-006 significantly ameliorated memory impairments in APP/PS1 transgenic mice. These multiple functions of a single molecule suggest that T-006 is a promising novel neuroprotective agent for treating various neurodegenerative disorders, including and in particular Alzheimer's disease.

A novel tetramethylpyrazine bis-nitrone (TN-2) protects against 6-hydroxyldopamine-induced neurotoxicity via modulation of the NF-κB and the PKCα/PI3-K/Akt pathways.

INTRODUCTION: The natural product tetramethylpyrazine (TMP) has a variety of biologic activities, including neuroprotection. Nitrones are powerful free radical scavengers. We have designed and synthesized a TMP derivative, TN-2, which is armed with two nitrone moieties. AIMS: In this study, we investigated the neuroprotective effect of TN-2 against 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in vitro and in zebrafish. METHODS: PC12 cells, zebrafish and rats were exposed to 6-OHDA challenge. MTT assay, LDH release, Hoechst staining, DAF-FM staining, luciferase reporter construct transfection, and western blotting were applied to detect cell viability, apoptosis, intracellular nitric oxide (NO), NF-κB transcriptional activity and proteins expression. In zebrafish, whole-mount staining and real-time PCR were performed to quantify dopaminergic neurons and mRNA expression. Hematoxylin and eosin staining and immunohistochemistry for glial fibrillary acidic protein were used to detect the astrocyte activation in the unilateral 6-OHDA rat model. RESULTS: TN-2 but not TMP exhibited potent neuroprotective effect against 6-OHDA-induced apoptosis in PC12 cells. Moreover, TN-2 prevented dopaminergic neuron loss and suppressed mRNA expression of pro-inflammatory genes, including IL-1ß, TNF-α and COX-2, in 6-OHDA-treated zebrafish. TN-2 remarkably attenuated microglial/astrocyte activation in the unilateral 6-OHDA rat model. The mechanistic study demonstrated that TN-2 inhibited over-production of intracellular NO and protein expression of inducible nitric oxide synthase through down-regulating NF-κB activity. Additionally, the PKCα/PI3-K/Akt pathway was also involved in the neuroprotection of TN-2. CONCLUSION: These results suggest that TN-2 protected against 6-OHDA-induced neurotoxicity via modulating the NF-κB-medicated neuroinflammation and PKCα/PI3-K/Akt pathways.