CNS Neuroscience & Therapeutics

Published by Wiley

Online ISSN: 1755-5949

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Print ISSN: 1755-5930

Articles


Histamine Modulation of Acute Nociception Involves Regulation of Na v 1.8 in Primary Afferent Neurons in Mice
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June 2013

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21 Reads

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Aims: To explore the role of histamine in acute pain perception and its possible mechanisms. Methods: Pain-like behaviors induced by four types of noxious stimuli (hot-plate, tail-pressure, acetic acid, and formalin) were accessed in mice. Nav 1.8 expression and functions in primary afferent neurons were compared between histidine decarboxylase knockout (HDC(-/-) ) mice and their wild-types. Results: HDC(-/-) mice, lacking in endogenous histamine, showed elevated sensitivity to all these noxious stimuli, as compared with the wild-types. In addition, a depletion of endogenous histamine with α-fluoromethylhistidine (α-FMH), a specific HDC inhibitor, or feeding mice a low-histamine diet also enhanced nociception in the wild-types. Nav 1.8 expression in primary afferent neurons was increased both in HDC(-/-) and in α-FMH-treated wild-type mice. A higher Nav 1.8 current density, a lower action potential (AP) threshold, and a higher firing rate in response to suprathreshold stimulation were observed in nociception-related small DRG neurons of HDC(-/-) mice. Nav 1.8 inhibitor A-803467, but not TTX, diminished the hyperexcitability and blocked repetitive AP firing of these neurons. Conclusion: Our results indicate that histamine participates in acute pain modulation in a dose-related manner. The regulation of Nav 1.8 expression and the excitability of nociceptive primary afferent neurons may be involved in the underlying mechanisms.
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Figure 1: Patient disposition throughout the study (randomized population). AEs, adverse events; N, number of patients in the population; n, number of patients with an assessment. One patient in each treatment group was randomized, but was not exposed to study medication.
Figure 2: Least-squares means change from baseline to Week 24 on (A) SIB and (B) ADCS-ADL-SIV (modified full analysis set). ADCS-ADL-SIV, Alzheimer's Disease Cooperative Study–Activities of Daily Living scale–Severe Impairment Version; SEM, standard error of the least-squares means; SIB, Severe Impairment Battery. Error bars represent the SEM. *P < 0.05; **P < 0.0001 versus 4.6 mg/24 h patch.
Table 3 Most frequent AEs a by treatment and preferred term in the 24-week treatment phase
A 24-Week, Randomized, Controlled Trial of Rivastigmine Patch 13.3 mg/24 h Versus 4.6 mg/24 h in Severe Alzheimer's Dementia
  • Article
  • Full-text available

August 2013

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288 Reads

The 24-week, prospective, randomized, double-blind ACTION study investigated the efficacy, safety, and tolerability of 13.3 versus 4.6 mg/24 h rivastigmine patch in patients with severe Alzheimer's disease (AD). Patients had probable AD and Mini-Mental State Examination scores ≥3-≤12. Primary outcome measures were as follows: Severe Impairment Battery (SIB) and AD Cooperative Study-Activities of Daily Living scale-Severe Impairment Version (ADCS-ADL-SIV). Secondary outcomes were as follows: ADCS-Clinical Global Impression of Change (ADCS-CGIC), 12-item Neuropsychiatric Inventory (NPI-12), and safety/tolerability. Of 1014 patients screened, 716 were randomized to 13.3 mg/24 h (N = 356) or 4.6 mg/24 h (N = 360) patch. Baseline characteristics/demographics were comparable. Completion rates were as follows: 64.3% (N = 229) with 13.3 mg/24 h and 65.0% (N = 234) with 4.6 mg/24 h patch. The 13.3 mg/24 h patch was significantly superior to 4.6 mg/24 h patch on cognition (SIB) and function (ADCS-ADL-SIV) at Week 16 (P < 0.0001 and P = 0.049, respectively) and 24 (primary endpoint; P < 0.0001 and P = 0.025). Significant between-group differences (Week 24) were observed on the ADCS-CGIC (P = 0.0023), not NPI-12 (P = 0.1437). A similar proportion of the 13.3 mg/24 h and 4.6 mg/24 h patch groups reported adverse events (AEs; 74.6% and 73.3%, respectively) and serious AEs (14.9% and 13.6%). The 13.3 mg/24 h patch demonstrated superior efficacy to 4.6 mg/24 h patch on SIB and ADCS-ADL-SIV, without marked increase in AEs, suggesting higher-dose patch has a favorable benefit-to-risk profile in severe AD.
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Figure 1 Chemical structures of ascomycin and FK506.
Sierra-Paredes G, Sierra-Marcuno GAscomycin and FK506: pharmacology and therapeutic potential as anticonvulsants and neuroprotectants. CNS Neurosci Ther 14:36-46

February 2008

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123 Reads

Ascomycin and FK506 are powerful calcium-dependent serine/threonine protein phosphatase (calcineurin [CaN], protein phosphatase 2B) inhibitors. Their mechanism of action involves the formation of a molecular complex with the intracellular FK506-binding protein-12 (FKBP12), thereby acquiring the ability to interact with CaN and to interfere with the dephosphorylation of various substrates. Pharmacological studies of ascomycin, FK506, and derivatives have mainly been focused on their action as immunosuppressants and therapeutic use in inflammatory skin diseases, both in animal studies and in humans. CaN inhibitors have been also proposed for the treatment of inflammatory and degenerative brain diseases. Preclinical studies suggest, however, that ascomycin and its derivatives exhibit additional pharmacological activities. Ascomycin has been shown to have anticonvulsant activity when perfused into the rat hippocampus via microdialysis probes, and ascomycin derivatives may be useful in preventing ischemic brain damage and neuronal death. Their pharmacological action in the brain may involve CaN-mediated regulation of gamma aminobutyric acid (GABA) and glutamate receptor channels, neuronal cytoskeleton and dendritic spine morphology, as well as of the inflammatory responses in glial cells. FK506 and ascomycin inhibit signaling pathways in astrocytes and change the pattern of cytokine and neurotrophin gene expression. However, brain-specific mechanisms of action other than CaN inhibition cannot be excluded. CaN is a likely potential target molecule in the treatment of central nervous system (CNS) diseases, so that the therapeutic potential of ascomycin, FK506, and nonimmunosuppressant ascomycin derivatives as CNS drugs should be further explored.

Lee Y, Park S, Shin H, Kim C, Lee W, Hong KProtective effects of cilostazol against transient focal cerebral ischemia and chronic cerebral hypoperfusion injury. CNS Neurosci Ther 14:143-152

February 2008

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145 Reads

Cilostazol increases intracellular cyclic adenosine monophosphate (cyclic AMP) levels by inhibiting type III phosphodiesterase. It was approved by the Food and Drug Administration for the treatment of intermittent claudication. Its principal actions include inhibition of platelet aggregation, antithrombotic action in cerebral ischemia, and vasodilation, mediated by increased cyclic AMP levels. In a multicenter, randomized, placebo-controlled, double-blind clinical trial, cilostazol has been shown to protect patients from recurrent cerebral infarction. It has been recently suggested that cilastozol could be useful in the treatment of transient focal cerebral ischemic injury. Beneficial effects of cilostazol in cerebral ischemic infarction and edema formation has been confirmed in rats by the magnetic resonance imaging (MRI). The preventive effect was ascribed to cAMP-dependent protein kinase (PKA)-coupled maxi-K channel activation with additional antioxidant and poly(adenosine diphosphate [ADP]-ribose) polymerase inhibitory actions. Most recently, cilostazol has been shown to prevent vacuolation and rarefaction in the white matter of the rats subjected to chronic cerebral hypoperfusion in association with suppression of astrocyte and microglial activation. Taken together, recent experimental studies with cilostazol showed promising results in cerebral ischemia and chronic cerebral hypoperfusion.

Popescu BF, Nichol HMapping brain metals to evaluate therapies for neurodegenerative disease. CNS Neurosci Ther 17:256-268

August 2011

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35 Reads

The brain is rich in metals and has a high metabolic rate, making it acutely vulnerable to the toxic effects of endogenously produced free radicals. The abundant metals, iron and copper, transfer single electrons as they cycle between their reduced (Fe(2+) , Cu(1+) ) and oxidized (Fe(3+) , Cu(2+) ) states making them powerful catalysts of reactive oxygen species (ROS) production. Even redox inert zinc, if present in excess, can trigger ROS production indirectly by altering mitochondrial function. While metal chelators seem to improve the clinical outcome of several neurodegenerative diseases, their mechanisms of action remain obscure and the effects of long-term use are largely unknown. Most chelators are not specific to a single metal and could alter the distribution of multiple metals in the brain, leading to unexpected consequences over the long-term. We show here how X-ray fluorescence will be a valuable tool to examine the effect of chelators on the distribution and amount of metals in the brain.

Kocsis B, Brown RE, McCarley RW, Hajos M. Impact of ketamine on neuronal network dynamics: translational modeling of schizophrenia-relevant deficits. CNS Neurosci Ther 19: 437-447
Subanesthetic doses of the psychomimetic, ketamine, have been used for many years to elicit behavioral effects reminiscent of schizophrenia in both healthy humans and in animal models of the disease. More recently, there has been a move toward the use of simple neurophysiological measures (event-related potentials, brain oscillations) to assay the functional integrity of neuronal circuits in schizophrenia as these measures can be assessed in patients, healthy controls, intact animals, and even in brain slices. Furthermore, alterations of these measures are correlated with basic information processing deficits that are now considered central to the disease. Thus, here we review recent studies that determine the effect of ketamine on these measures and discuss to what extent they recapitulate findings in patients with schizophrenia. In particular, we examine methodological differences between human and animal studies and compare in vivo and in vitro effects of ketamine. Ketamine acts on multiple cortical and subcortical sites, as well as on receptors other than the N-methyl-d-aspartate receptor. Acute ketamine models' changes correlated with psychotic states (e.g. increased baseline gamma-band oscillations), whereas chronic ketamine causes cortical circuit changes and neurophysiological deficits (e.g. impaired event-related gamma-band oscillations) correlated with cognitive impairments in schizophrenia.

Characterization of a Synthetic Steroid 24-keto-cholest-5-en-3, 19-diol as a Neuroprotectant

February 2015

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17 Reads

Neuroactive steroids represent promising candidates for the treatment of neurological disorders. Our previous studies identified an endogenous steroid cholestane-3β, 5α, 6β-triol (Triol) as a novel neuroprotectant. We aimed to identify a potent candidate for stroke treatment through a screening of Triol analogs. Hypoxia- and glutamate-induced neuronal injury models in vitro, middle cerebral artery occlusion (MCAO)-induced cerebral ischemia model in vivo, fluorescein diacetate (FDA) for alive and propidium iodide (PI) for dead staining, LDH assay, and calcium imaging techniques were used. 24-keto-cholest-5-en-3β, 19-diol (Diol) showed the most potent neuroprotective effect among the screened structurally related compounds. FDA and PI staining showed that Diol concentration dependently increased the survival rate of cerebellar granule neurons (CGNs) challenged with glutamate or hypoxia, with an effective threshold concentration of 2.5 μM. Consistently, the quantitative LDH release assay showed the same concentration-dependent protection in both models. Diol, at 10 μM, potently decreased glutamate- and hypoxia-induced LDH release from 51.6 to 18.2% and 62.1 to 21.7%, respectively, which values are close to the normal LDH release (~16-18%). Moreover, we found Diol effectively decreased MCAO-induced infarction volume in mice from ~23% to 7%, at a dose of 6 mg/kg. We further explored the underlying mechanism and found that Diol attenuated NMDA-induced intracellular calcium ([Ca(2+) ]i ) increase in cortical neurons, suggesting a negative modulatory effect on NMDA receptor. Taken together, we identified Diol as a potent neuroprotectant. It may represent a novel and promising neuroprotectant for stroke intervention. © 2015 John Wiley & Sons Ltd.

Zinc Promotes the Death of Hypoxic Astrocytes by Upregulating Hypoxia-Induced Hypoxia-Inducible Factor-1alpha Expression via Poly(ADP-ribose) Polymerase-1

April 2013

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83 Reads

Pathological release of excess zinc ions has been implicated in ischemic brain cell death. However, the underlying mechanisms remain to be elucidated. In stroke, ischemia-induced zinc release and hypoxia-inducible factor-1 (HIF-1) accumulation concurrently occur in the ischemic tissue. The present study tests the hypothesis that the presence of high intracellular zinc concentration is a major cause of modifications to PARP-1 and HIF-1α during hypoxia, which significantly contributes to cell death during ischemia. Primary cortical astrocytes and C8-D1A cells were exposed to different concentrations of zinc chloride. Cell death rate and protein expression of HIF-1 and Poly(ADP-ribose) polymerase (PARP)-1 were examined after 3-h hypoxic treatment. Although 3-h hypoxia or 100 μM of zinc alone did not induce noticeable cytotoxicity, their combination led to a dramatic increase in astrocytic cell death in a zinc-concentration-dependent manner. Exposure of astrocytes to hypoxia for 3 h remarkably increased the levels of intracellular zinc and HIF-1α protein, which was further augmented by added exogenous zinc. Notably, HIF-1α knockdown blocked zinc-induced astrocyte death. Moreover, knockdown of PARP-1, another important protein in the response of hypoxia, attenuated the overexpression of HIF-1α and reduced the cell death rate. Our studies show that zinc promotes hypoxic cell death through overexpression of the hypoxia response factor HIF-1α via the cell fate determine factor PARP-1 modification, which provides a novel mechanism for zinc-mediated ischemic brain injury.

The Migration of Neural Progenitor Cell Mediated by SDF‐1 is NF‐κB/HIF‐1α Dependent upon Hypoxia

January 2013

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52 Reads

Stromal cell-derived factor 1 (SDF-1) is critical for neural progenitor cell (NPC) migration after ischemia for nerve repair, but how hypoxic induction of SDF-1 is regulated has not been fully addressed. Here, we examined the regulation of SDF-1 hypoxic induction by the transcription factors nuclear factor-κB (NF-κB) and hypoxic inducible factor 1α (HIF-1α) in astrocytes. Stromal cell-derived factor-1 in astrocyte-conditioned medium (ACM) collected from hypoxic astrocytes induced a time- and dose-dependent increase in NPC migration using chemotaxis assay. The increase in NPC migration correlated with increased SDF-1 production in astrocytes by real-time PCR and ELISA assays. Astrocytes produced SDF-1 time-dependently upon 3% O2 treatment, which was associated with increased levels of NF-κB and HIF-1α using Western blot analysis. Anti-HIF-1α compound, 3-(5′-hydroxymethyl-2′-furyl)-1-benzylindazole (YC-1) and NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC), decreased hypoxic induction of SDF-1, and PDTC pretreatment cancelled HIF-1α expression as well, thus NPC migration induced by ACM was decreased accordingly. Moreover, lentiviurs siRNA for NF-κB p65 abrogated induction of HIF-1α and SDF-1 under hypoxia in astrocytes. Hypoxic induction of SDF-1 is reliant upon NF-κB and HIF-1α. There is a cross-talk between HIF-1α and NF-κB, both HIF-1α and SDF-1 are downstream targets of NF-κB in hypoxia condition.

MicroRNA-21 Expression is regulated by ss-catenin/STAT3 Pathway and Promotes Glioma Cell Invasion by Direct Targeting RECK

May 2012

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27 Reads

MicroRNA-21 (miR-21) expression is increased in many types of human malignancy, including glioma. Recent studies report that miR-21 regulates cell invasion by targeting RECK, however, the underlying transcriptional regulation of miR-21 in glioma cells remains elusive. Here, we identify a positive correlation between miR-21 expression and pathological grade in glioma tissues. We demonstrate that β-catenin pathway regulates miR-21 expression in human umbilical vein endothelial cell and glioma cells, and that this regulation is signal transducer and activator of transcription 3 (STAT3)-dependent. Further, chromatin immunoprecipitation and luciferase reporter analysis demonstrate that miR-21 is controlled by an upstream promoter containing a conserved STAT3 binding site. Notably, knockdown of miR-21-inhibited cell invasion by increasing RECK expression and decreased tumor growth in a xenograft model. These data provide compelling evidence that β-catenin regulation of miR-21 via STAT3 plays a role in glioma cell invasion and proliferation and indicate that STAT3 is a potential therapeutic target for glioma intervention.

MiR-21 modulates hTERT through a STAT3-dependent manner on glioblastoma cell growth

June 2012

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41 Reads

As an important oncogenic miRNA, miR-21 has been reported to play crucial roles in glioblastoma (GBM) carcinogenesis. However, the precise biological function and molecular mechanism of miR-21 in GBM remain elusive. This study is designed to explore the mechanism of miR-21 involved in the control of GBM cell growth. MTT assay, cell cycle analysis, and apoptosis analysis showed that reduction of miR-21 inhibited cell growth in U87 and LN229 GBM cells. Further, reduction of miR-21 decreased the expression of human telomerase reverse transcriptase (hTERT) and repressed STAT3 expression and STAT3 phosphorylation. STAT3 inhibition led to a remarkable depletion of hTERT at both mRNA and protein levels by binding to the hTERT gene promoter by performing luciferase reporter assay and chromatin Immunoprecipitation PCR. Finally, knockdown of miR-21 considerably inhibited tumor growth and diminished the expression of STAT3 and hTERT in xenograft model. Our findings indicate that miR-21 regulates hTERT expression mediated by STAT3, therefore controlling GBM cell growth.

A Multicenter, Placebo-Controlled, Double-Blind, Randomized Study of Efficacy and Safety of Ocinaplon (DOV 273,547) in Generalized Anxiety Disorder

April 2010

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62 Reads

Preclinical studies demonstrated that ocinaplon, a positive allosteric modulator of GABA(A) receptors, possesses anxiolytic-like actions at doses devoid of the side effects typically associated with benzodiazepines. The aim of this study was to evaluate the effects of ocinaplon in a multicenter, double-blind proof-of-concept trial of male and female outpatients who met DSM-IV criteria for GAD with no coexisting depression, and had a baseline score of > or =20 on the Hamilton Scale for Anxiety (HAM-A). Patients with <20% reduction in HAM-A to placebo in a single-blind 7-day run-in period were randomly assigned to treatment with ocinaplon 90 mg t.i.d. (n = 31) or placebo for 28 days (n = 29). Ocinaplon was more effective than placebo in reducing HAM-A scores (P= 0.009). Patients assigned to ocinaplon exhibited a mean improvement of 14.2 points (SE = 2.6) on the total score of the HAM-A scale at the conclusion of the trial, while patients assigned to placebo obtained a mean improvement of 6.3 points (SE = 2.0). A significant (P= 0.023) difference in improvement between ocinaplon and placebo was observed beginning at and continuing from 1-week after the initiation of dosing. The proportion of patients with treatment-emergent adverse events (TEAE) was not statistically significant between ocinaplon and placebo. One serious adverse event (SAE) occurred in the ocinaplon group that was considered possibly related to study medication (icterus following transaminase elevations). The patient had preexisting medical conditions that may have contributed to this SAE. A full recovery was observed with no residual effects. The overall safety profile revealed no patterns of TEAEs, including those effects typically associated with other anxiolytic and/or benzodiazepine compounds, such as sedation. Ocinaplon appears to be a well-tolerated and effective treatment for GAD. It produces a rapid onset of anxiolytic action absent the side effects (e.g., dizziness, sedation) typically reported following anxiolytic doses of benzodiazepines.

Administration of MS-275 Improves Cognitive Performance and Reduces Cell Death Following Traumatic Brain Injury in Rats

March 2013

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34 Reads

Aims: The MS-275 is a selective inhibitor of class I histone deacetylases (HDACs), which has been reported as a potential strategy in some central nervous system diseases associated with neurodegeneration and disturbed learning. However, its role in traumatic brain injury is not well defined. In this study, we examined the behavioral-cognitive performance as well as histology outcome in adult rats to evaluate whether postinjury administration of MS-275 (15 and 45 mg/kg) would provide neuroprotection benefits and ameliorate cognitive deficits following fluid percussion injury. Methods: Traumatic brain injury (˜2.15 ATMs) was produced using a fluid percussion device with the lateral orientation. MS-275 was administered (15 and 45 mg/kg) systemically once daily for 7 days starting at 30 min after lateral fluid percussion TBI. Acquisition of spatial learning and memory retention was assessed using the Morris water maze (MWM) on days 10-14 after TBI. Brain tissues were collected and stained with Fluoro-Jade B histofluorescence (for degenerating neurons) at 24 h after injury and cresyl violet (for long-term neuronal survival) on day 14 postinjury. Results: Behavioral outcome after TBI revealed MS-275 treatment groups, at all doses examined, performed significantly better in the Morris Water Maze (P < 0.001). Acute histology analysis demonstrated that 45 mg/kg MS-275 significantly reduced the number of degenerating neurons in the ipsilateral CA2-3 hippocampus at 24 h postinjury (P = 0.007). There was a trend for MS-275 to increase the survival of neurons in the CA2-3 hippocampus on 14 days after TBI (P = 0.164). Conclusion: Our present data highlight the fact that MS-275 may provide neuroprotective effect and improve cognitive performance after TBI. We concluded that MS-275 is a potential novel treatment and will have an ameliorative effect on some of the pathological features associated with TBI.

MicroRNA-29c Correlates with Neuroprotection Induced by FNS by Targeting Both Birc2 and Bak1 in Rat Brain after Stroke

February 2015

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28 Reads

Studies showed fastigial nucleus stimulation (FNS) reduced brain damage, but the mechanisms of neuroprotection induced by FNS were not entirely understood; MicroRNAs are noncoding RNA molecules that regulate gene expression in a posttranscriptional manner, but their functional consequence in response to ischemia-reperfusion (IR) remains unknown. We investigated the role of microRNA-29c in the neuroprotection induced by FNS in rat. The IR rat models were conducted 1 day after FNS. Besides, miR-29c antagomir (or agomir or control) was infused to the left intracerebroventricular 1 day before IR models were conducted. We detected differential expression of Birc2 mRNA (also Bak1mRNA and miR-29c) level among different groups by RT-qPCR. The differential expression of Birc2 protein (also Bak1 protein) level among different groups was surveyed via Western blot. The neuroprotective effects were assessed by infarct volume, neurological deficit, and apoptosis. MiR-29c was decreased after FNS. Moreover, miR-29c directly bound to the predicted 3'-UTR target sites of Birc2 and Bak1 genes. Furthermore, over-expression of miR-29c effectively reduced Birc2 (also Bak1) mRNA and protein levels, increased infarct volume and apoptosis, and deteriorated neurological outcomes, whereas down-regulation played a neuroprotective role. MiR-29c correlates with the neuroprotection induced by FNS by negatively regulating Birc2 and Bak1. © 2015 John Wiley & Sons Ltd.

Simvastatin Exerts Antiamnesic Effect in Aβ 25-35 -Injected Mice

December 2013

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27 Reads

Simvastatin (SV) is reported to improve cognition and slow the progression of Alzheimer's disease (AD). This study explored the mechanisms underlying the antiamnesic effect of SV in AD using behavior tests, histological examination, western blot analysis, and electrophysiological recording technique in AD model mice created by intracerebroventricular injection (i.c.v.) of Aβ25-35 . Chronic administration of SV (40 mg/kg/day) for 11 days after Aβ25-35 -injection ameliorated the impairment of acquisition performance and probe trail test in Morris water maze task and alternation behavior in Y maze task in Aβ25-35 -mice. Aβ25-35 -induced apoptosis of hippocampal CA1 pyramidal cells and Aβ25-35 -impaired high-frequency stimulation (HFS)-dependent long-term potentiation (LTP) induction in hippocampal Schaffer collaterale-CA1 synapse were rescued by SV-treatment. SV prevented Aβ25-35 -inhibited protein kinase B (Akt) and extracellular signal-related kinase-2 (ERK2) phosphorylation, which was sensitive to α7 nicotinic acetylcholine receptor (α7nAChR) antagonist MLA. SV-induced neuroprotection was attenuated by MLA or phosphatidylinositol-3-kinase (PI3K) antagonist LY294002. SV-rescued LTP induction was blocked by α7nAChR, PI3K or MAPK/ERK kinase (MEK) antagonist. Finally, the antiamnesia of SV in Aβ25-35 -mice was attenuated by blockage of SV-induced neuroprotection or SV-rescued LTP induction. The antiamnesia of SV in Aβ25-35 -mice depends on its neuroprotection and synaptic plasticity improvement.

p53-Induced Uncoupling Expression of Aquaporin-4 and Inwardly Rectifying K+ 4.1 Channels in Cytotoxic Edema after Subarachnoid Hemorrhage

March 2012

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20 Reads

To investigate the mechanism behind cytotoxic edema formation following subarachnoid hemorrhage (SAH). We explored the role of aquaporin-4 (AQP4), inwardly rectifying K(+) 4.1 (Kir4.1) channels and their upstream orchestrators p53 and p38MAPK in this process. A p53 inhibitor, pifithrin-α (PFT-α) was administered intraperitoneally to rats undergoing SAH by endovascular perforation. Totally, 98 male SD rats were categorized into sham, SAH, SAH+ dimethyl sulfoxide (DMSO), SAH+ 0.2 or 2.0 mg/kg PFT-α groups. At 24 h after SAH, MRI (diffusion-weighted imaging [DWI]), immunohistochemistry, and Western blot were used. MRI (DWI) showed a significant cytotoxic edema in the brain following SAH with PFT-α therapy reducing it. Immunohistochemistry and Western blot showed an increased level of p53, phosphorylated-p38MAPK and AQP4 and a reduced level of Kir4.1; all of which could be reversed following PFT-α treatment. Treble labeling staining revealed colocalization of p53 with phosphorylated-p38MAPK and unmatched expression of AQP4 and Kir4.1 within astrocyte cells. These results indicated p53 mediates the formation of cytotoxic edema in the brain following SAH; an uncoupling expression of AQP4 and Kir4.1 on astrocytic end feets orchestrated by p38MAPK was partly responsible.

Implementation and Outcome of Thrombolysis with Alteplase 3 to 4.5 h After Acute Stroke in Chinese Patients

December 2012

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65 Reads

Background and purpose: The European Cooperative Acute Stroke Study (ECASS) III showed that intravenous recombinant tissue plasminogen activator (rtPA) administered in the 3 to 4.5 h after symptom onset significantly improved clinical outcomes in patients with acute ischemic stroke (AIS). But little is known regarding the safety and efficacy of intravenous rtPA treatment within this extended time window in Chinese patients with AIS. Methods and results: Data were collected from the Thrombolysis Implementation and Monitor of acute ischemic Stroke in China (TIMS-China). A total of 574 patients who underwent rtPA therapy within 4.5 h after symptom onset were included in this study: 409 in the 0- to 3-h group and 165 in the 3- to 4.5-h group. There were no significant differences in SICH rate (2.4% vs. 1.5%, P = 0.70) at 24 to 36 h, mortalities (7.5% vs. 7.3%, P = 0.84), independence rate (68.9% vs. 63.9%, P = 0.19), and excellent recovery rate (60.9% vs. 52.4%, P = 0.11) between the two time window groups. These results were comparable with previous Western studies. Conclusion: This study suggests that intravenous rtPA treatment at 3 to 4.5 h of symptom onset remains safe and effective in Chinese patients with AIS.

Diammonium Glycyrrhizinate Attenuates Aβ1-42-Induced Neuroinflammation and Regulates MAPK and NF-κB Pathways In Vitro and In Vivo

December 2012

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18 Reads

Beta-amyloid (Aβ)-mediated inflammation contributes to the progression and chronicity of Alzheimer's disease (AD), although the exact mechanism remains unclear. This study aimed to investigate whether diammonium glycyrrhizinate (DG) could inhibit Aβ-induced inflammation in vitro and in vivo and to explore the underlying mechanisms. Aβ1–42 was injected to bilateral hippocampus of mice to make the AD models in vivo. The levels of mRNA and protein of inflammatory cytokines were measured by real-time PCR and Western blotting, respectively. The viability of SH-SY5Y and HT-22 cells was determined by MTT. NF-κB p65 translocation was analyzed by Western blotting and immunostaining. Phosphorylation of ERK, p38, and JNK was tested by Western blotting. DG suppressed Aβ1–42-induced activation of microglia and inflammation in vitro and in vivo. The media from Aβ1–42-activated microglia decreased the viability of SH-SY5Y and HT-22 cells, but it was rescued when pretreated with DG. DG could inhibit the activation of MAPK and NF-κB signaling pathways and attenuate the memory deficits in Aβ1–42-induced AD mice. DG protects Aβ1–42-induced AD models in vitro and in vivo through reducing activation of microglia and inflammation, which may be involved in MAPK and NF-κB pathways.


TC-5214 (S-(+)-Mecamylamine): A Neuronal Nicotinic Receptor Modulator with Antidepressant Activity

February 2008

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62 Reads

Both clinical and preclinical data support a potential therapeutic benefit of modulating the activity of CNS neuronal nicotinic receptors (NNRs) to treat depression and anxiety disorders. Based on the notion that the depressive states involve hypercholinergic tone, we have examined the potential palliative role of NNR antagonism in these disorders, using TC-5214 (S-(+) enantiomer of mecamylamine), a noncompetitive NNR antagonist. TC-5214 demonstrated positive effects in a number of animal models of depression and anxiety. TC-5214 was active in the forced swim test in rats (minimum effective dose (MED)=3 mg/kg i.p.), a classical depression model. It was also active in the behavioral despair test in mice (0.1-3.0 mg/kg i.p.), another model of depression. In the social interaction paradigm in rats, a model of generalized anxiety disorder (GAD), TC-5214 was active at a dose of 0.05 mg/kg s.c. In the light/dark chamber paradigm in rats, a model of GAD and phobia, TC-5214 was also active at a dose of 0.05 mg/kg s.c. Although TC-5214 shows modest selectivity among NNR subtypes, the antidepressant and anxiolytic effects seen in these studies are likely attributable to antagonist effects at the alpha4beta2 NNRs. This is supported by the observation of similar effects with alpha4beta2-selective partial agonists such as cytisine and with alpha4beta2-selective antagonists such as TC-2216. TC-5214 was well tolerated in acute and chronic toxicity studies in mice, rats, and dogs, showed no mutagenicity and displayed safety pharmacology, pharmacokinetic and metabolic profiles appropriate for therapeutic development. Overall, the results support a novel nicotinic cholinergic antagonist mechanism for antidepressant and anxiolytic effects and highlight the potential of NNR antagonists such as TC-5214 as therapeutics for the treatment of anxiety and depression.

Preclinical Characterization of A-582941: A Novel ??7 Neuronal Nicotinic Receptor Agonist with Broad Spectrum Cognition-Enhancing Properties

February 2008

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76 Reads

Among the diverse sets of nicotinic acetylcholine receptors (nAChRs), the alpha7 subtype is highly expressed in the hippocampus and cortex and is thought to play important roles in a variety of cognitive processes. In this review, we describe the properties of a novel biaryl diamine alpha7 nAChR agonist, A-582941. A-582941 was found to exhibit high-affinity binding and partial agonism at alpha7 nAChRs, with acceptable pharmacokinetic properties and excellent distribution to the central nervous system (CNS). In vitro and in vivo studies indicated that A-582941 activates signaling pathways known to be involved in cognitive function such as ERK1/2 and CREB phosphorylation. A-582941 enhanced cognitive performance in behavioral models that capture domains of working memory, short-term recognition memory, memory consolidation, and sensory gating deficit. A-582941 exhibited a benign secondary pharmacodynamic and tolerability profile as assessed in a battery of assays of cardiovascular, gastrointestinal, and CNS function. The studies summarized in this review collectively provide preclinical validation that alpha7 nAChR agonism offers a mechanism with potential to improve cognitive deficits associated with various neurodegenerative and psychiatric disorders.

Figure 1: Chromatogram of the novel c.133_136delCCAG mutation within PRRT2 gene. The upper panel is the normal sequence, whereas the lower panel represents heterozygous mutated sequence.
Figure 2: Haplotype analysis based on 18 single nucleotide polymorphisms (SNPs) flanking the PRRT2. The large box lists the reference ID, position, alleles, and allele frequency for each of 18 SNPs included in the analysis. Numbers below the squares or circles represent the genotypes of the 18 SNPs for each individual (1 and 2 denote the specific allele for each SNP). The probability of the patient being biological son of the alleged parents was calculated as 99.93%.
PRRT2 c.649dupC Mutation Derived from De Novo in Paroxysmal Kinesigenic Dyskinesia

November 2012

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76 Reads

PRRT2 was recently identified as a causative gene for paroxysmal kinesigenic dyskinesia (PKD), and the c.649dupC mutation was shown to be a “high frequency” mutation. This mutation was also identified in many sporadic cases. This might be attributed to the incomplete penetrance of c.649dupC. Alternatively, c.649dupC might derive from de novo. The aim of this study is to elucidate the possibility concerning de novo mutagenesis of PRRT2 mutations in PKD. Nine sporadic Chinese PKD patients including one Mongolian patient were recruited. Direct sequencing of PRRT2 was performed in them and their parents. Haplotype analysis was conducted to confirm the biological relationship. A novel mutation, c.133_136delCCAG, was identified in one Han patient and his unaffected mother. The c.649dupC mutation was detected in another Han patient and his unaffected father. To our interest, c.649dupC was detected in the Mongolian patient but not in his parents. Haplotype analysis confirmed the biological relationship among the trio. No mutations were identified in the remaining six patients. These findings demonstrate the heterogeneity of PKD, and the de novo mutagenesis of PRRT2 gene might indicate the genetic instability of this region.


The Uncoupling Protein 2 -866G > A Polymorphism is Associated with the Risk of Ischemic Stroke in Chinese Type 2 Diabetic Patients

May 2012

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6 Reads

To determine genetic predispsitions for diabetic cerebral ischemia, we investigated the relationship between the -866G>A polymorphism of uncoupling protein (UCP) 2 and the risk of ischemic stroke in two cohorts of type 2 diabetic patients. A total of 844 type 2 diabetic patients with 4-year prospective study were examined using a case-control methodology. And 404 cases with ischemical stroke, 440 cases without ischemical stroke. The -866G>A polymorphism in UCP2 was genotyped by TaqMan MGB probe method. The -866G>A SNP in UCP2 was significantly associated with diabetic ischemical stroke (odds ratio [OR]= 1.94; 95% confidence interval [CI]= 0.68 to1.31; P < 0.037). Similar results were observed for baseline cases of IS. Stratification by sex confirmed an allelic association with IS in women, whereas no association was observed in men. The A allele of the -866G>A variant of UCP2 was associated with increased risk of IS in Chinese diabetic women with type 2 diabetes in a 4-year prospective study. This association was independent of other common IS risk factors.

ABCC2 Polymorphisms and Haplotype are Associated with Drug Resistance in Chinese Epileptic Patients

May 2012

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52 Reads

Some study found that ATP-binding cassette (ABC) efflux transporters play an important role in antiepileptic drug resistance, especially ABCB1 and ABCC2. The aims of this study were to evaluate the relationship between the genetic polymorphisms of ABCC2 and ABCB1 and the therapeutic efficacy of antiepileptic drugs (AEDs) in Chinese epileptic patients. ABCB1 rs1045642 (3435C>T) and ABCC2 rs717620 (-24C>T), rs3740066 (3972C>T), and rs2273697 (1249G>A) polymorphisms loci in 537 Chinese epilepsy patients (217 drug resistant patients and 320 drug responders) were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). ABCC2 rs717620 -24TT genotype was significantly associated with drug resistant epilepsy (odds ratio [OR]= 4.06 [1.79-9.20], P= 0.001). The OR values of ABCC2 rs717620 -24 CT+TT genotypes and ABCC2 rs3740066 (3972C>T) CT+TT genotypes were markedly higher in drug resistant patients (OR = 1.57 [1.08-2.29], P= 0.018; OR = 1.49 [1.02-2.18], P= 0.038, respectively) compared with responsive patients. ABCC2 rs2273697 (1249G>A) and ABCB1 rs1045642 (3435C>T) polymorphisms were not associated with drug resistant epilepsy. Linkage disequilibrium (LD) test showed that the ABCC2 rs717620 were in strong LD with rs2273697 (D'= 0.694) and rs3740066 (D'= 0.699). The frequencies of haplotypes TGT (ABCC2 -24C>T/ABCC2 1249G>A/ABCC2 3972C>T) in resistant patients was significantly higher than those in responsive patients (21.0% vs. 14.2%, P < 0.05). ABCC2-24C>T, 3972C>T polymorphisms and one ABCC2 haplotype is associated with AED resistance; ABCC2 1249G>A and ABCB1 3435C>T polymorphisms are not associated with AED resistance in our study. These data suggest that ABCC2 polymorphisms and haplotype may affect the response of antiepileptic drugs.



Effects of Exogenous Agents on Brain Development: Stress, Abuse and Therapeutic Compounds

October 2011

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42 Reads

The range of exogenous agents likely to affect, generally detrimentally, the normal development of the brain and central nervous system defies estimation although the amount of accumulated evidence is enormous. The present review is limited to certain types of chemotherapeutic and "use-and-abuse" compounds and environmental agents, exemplified by anesthetic, antiepileptic, sleep-inducing and anxiolytic compounds, nicotine and alcohol, and stress as well as agents of infection; each of these agents have been investigated quite extensively and have been shown to contribute to the etiopathogenesis of serious neuropsychiatric disorders. To greater or lesser extent, all of the exogenous agents discussed in the present treatise have been investigated for their influence upon neurodevelopmental processes during the period of the brain growth spurt and during other phases uptill adulthood, thereby maintaining the notion of critical phases for the outcome of treatment whether prenatal, postnatal, or adolescent. Several of these agents have contributed to the developmental disruptions underlying structural and functional brain abnormalities that are observed in the symptom and biomarker profiles of the schizophrenia spectrum disorders and the fetal alcohol spectrum disorders. In each case, the effects of the exogenous agents upon the status of the affected brain, within defined parameters and conditions, is generally permanent and irreversible.


Effects of Acetazolamide on Transient K+ Currents and Action Potentials in Nodose Ganglion Neurons of Adult Rats

March 2010

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161 Reads

The aim of the present study was to determine whether acetazolamide (AZ) contributes to the inhibition of the fast inactivating transient K(+) current (I(A) ) in adult rat nodose ganglion (NG) neurons. We have previously shown that pretreatment with either AZ or 4-AP attenuated or blocked the CO(2) -induced inhibition of slowly adapting pulmonary stretch receptors in in vivo experiments. The patch-clamp experiments were performed by using the isolated NG neurons. In addition to this, the RT-PCR of mRNA and the expression of voltage-gated K(+) (Kv) 1.4, Kv 4.1, Kv 4.2, and Kv 4.3 channel proteins from nodose ganglia were examined. We used NG neurons sensitive to the 1 mM AZ application. The application of 1 mM AZ inhibited the I(A) by approximately 27% and the additional application of 4-AP (1 mM) further inhibited I(A) by 48%. The application of 0.1 μM α-dendrotoxin (α-DTX), a slow inactivating transient K(+) current (I(D) ) blocker, inhibited the baseline I(A) by approximately 27%, and the additional application of 1 mM AZ further decreased the I(A) by 51%. In current clamp experiments, AZ application (1 mM) increased the number of action potentials due to the decreased duration of the depolarizing phase of action potentials and/or due to a reduction in the resting membrane potential. Four voltage-gated K(+) channel proteins were present, and most (80-90%) of the four Kv channels immunoreactive neurons showed the co-expression of carbonic anhydrase-II (CA-II) immunoreactivity. These results indicate that the application of AZ causes the reduction in I(A) via the inhibition of four voltage-gated K(+) channel (Kv) proteins without affecting I(D).

Involvement of Acetylcholine-α7nAChR in the Protective Effects of Arterial Baroreflex against Ischemic Stroke

November 2012

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44 Reads

Decreased baroreflex sensitivity is associated with poor outcome in many cardiovascular diseases including stroke, but the molecular mechanism underlying this relationship is unclear. This work was designed to test the hypothesis that acetylcholine (ACh) and α7 nicotinic ACh receptor (α7nAChR) mediate the protection of arterial baroreflex against stroke. Sinoaortic denervation (SAD) was used to impair the function of arterial baroreflex, and anticholinesterase agents were used to activate the cholinergic system and increase endogenous ACh. Middle cerebral artery occlusion (MCAO) was performed in the α7nAChR knockout (KO) mice and Sprague-Dawley rats. We found decreased expression of vesicular ACh transporter (VAChT) and α7nAChR in rat brain after SAD. In rats subjected to MCAO, neostigmine significantly reduced the infarct size. The protective effects of neostigmine were abolished by selective nAChR antagonist vecuronium but not by mAChR antagonist anisodamine. In addition, the effect of neostigmine disappeared in α7nAChR KO mice. In cultured neurons, ACh inhibited cell death induced by H(2) O(2) . In cultured microglial cells, ACh decreased the release of proinflammatory cytokines induced by lipopolysaccharide. These in vitro effects were blocked by selective α7nAChR antagonists. Taken together, these findings indicate that the ACh-α7nAChR involved in the protective effects of arterial baroreflex against ischemic stroke.


Robust Neuritogenesis-Promoting Activity by Bis(heptyl)-Cognitin Through the Activation of alpha7-Nicotinic Acetylcholine Receptor/ERK Pathway

April 2015

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67 Reads

Neurodegenerative disorders are caused by progressive neuronal loss in the brain, and hence, compounds that could promote neuritogenesis may have therapeutic values. In this study, the effects of bis(heptyl)-cognitin (B7C), a multifunctional dimer, on neurite outgrowth were investigated in both PC12 cells and primary cortical neurons. Immunocytochemical staining was used to evaluate the proneuritogenesis effects, and Western blot and short hairpin RNA assays were applied to explore the underlying mechanisms. B7C (0.1-0.5 μM) induced robust neurite outgrowth in PC12 cells, as evidenced by the neurite-bearing morphology and upregulation of growth-associated protein-43 expression. In addition, B7C markedly promoted neurite outgrowth in primary cortical neurons as shown by the increase in the length of β-III-tubulin-positive neurites. Furthermore, B7C rapidly increased ERK phosphorylation. Specific inhibitors of alpha7-nicotinic acetylcholine receptor (α7-nAChR) and MEK, but not those of p38 or JNK, blocked the neurite outgrowth as well as ERK phosphorylation induced by B7C. Most importantly, genetic depletion of α7-nAChR significantly abolished B7C-induced neurite outgrowth in PC12 cells. B7C promoted neurite outgrowth through the activation of α7-nAChR/ERK pathway, which offers novel insight into the potential application of B7C in the treatment of neurodegenerative disorders. © 2015 John Wiley & Sons Ltd.

Meserine, a Novel Carbamate AChE Inhibitor, Ameliorates Scopolamine‐Induced Dementia and Alleviates Amyloidogenesis of APP/PS1 Transgenic Mice

November 2013

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50 Reads

To investigate whether Meserine, a novel phenylcarbamate derivative of (-)-meptazinol, possesses beneficial activities against cholinergic deficiency and amyloidogenesis, the two major pathological characteristics of Alzheimer's disease (AD). Ellman's assay and Morris water maze were used to detect acetylcholinesterase (AChE) activity and evaluate spatial learning and memory ability, respectively. Both high content screening and Western blotting were carried out to detect β-amyloid precursor protein (APP), while RT-PCR and ELISA were conducted to detect APP-mRNA and β-amyloid peptide (Aβ). In scopolamine-induced dementia mice, Meserine (1 mg/kg, i.p.) significantly ameliorated spatial learning and memory deficits, which was consistent with its in vitro inhibitory ability against AChE (recombinant human AChE, IC50 = 274 ± 49 nM). Furthermore, Meserine (7.5 mg/kg) injected intraperitoneally once daily for 3 weeks lowered APP level by 28% and Aβ42 level by 42% in APP/PS1 transgenic mouse cerebrum. This APP modulation action might be posttranscriptional, as Meserine reduced APP by about 30% in SH-SY5Y-APP695 cells but did not alter APP-mRNA level. And both APP and Aβ42 lowering action of Meserine maintained longer than that of rivastigmine. Meserine executes dual actions against cholinergic deficiency and amyloidogenesis and provides a promising lead compound for symptomatic and modifying therapy of AD.

Figure 1: RT-PCR results showed that all 10 GBM clinical specimens were wild-type EGFR+, and eight of the 10 were EGFRvIII+ (A). Lanes correspond to the patient number. DNA fragments of 1044 bp and 243 bp in size represented EGFR and EGFRvIII, respectively. MRI showed space-occupying lesions in all three patients (B). Patient No. 1. Space-occupying lesions were located in the left temporal lobe rear, and the midline structure shifted right. Patient No. 2 showed a class round abnormal signal shadow, and rich blood supply space-occupying lesions were located in the left temporal lobe rear. Patient No. 3 showed space-occupying lesions in the right frontal lobe, the right lateral ventricle was compressed by the tumor, and the midline structure shifted left. Flow cytometric analysis showed that the percentages of CD133+ cells from each patient were 1.1%, 3.6%, and 0.3% (C). The Caco2 cell line with CD133 overexpression was used as a positive control (D).
Figure 3: H&E staining of the brain tissues of NOD/SCID mice. Space-occupying lesions in the area between the cerebral cortex and dorsal hippocampus CA3, as well as many atypical and prominent nuclei, were found in high-magnification fields (A). The needle track of cell transplantation is shown in (B). Brain tissue sections were also analyzed by immunofluorescence. Some tumor cells were immunoreactive for CD133 (C), nestin (D), GFAP (E), and EGFRvIII (F). Nuclei were counterstained with DAPI. (Scale bars: A, B C, D, and F, 200 μm; E, 40 μm).
Figure 4: The growth inhibition curves of cells treated with gefitinib were determined by a CCK-8 assay. (A) Patient No. 10 without EGFRvIII expression. (B, C, and D) Patient No. 1–3, respectively. (E) Column diagram showing each IC50 value. Western blot results showed that the expression levels of CD133 (F), nestin (G), EGFR (H) in cells from Patient No. 1 were essentially stable, while phosphorylation of EGFR tyrosine 845 was slightly reduced at the indicated concentrations of EGF and gefitinib treatment (I). Caco2 cells and neurospheres were used as positive controls. Lanes 1, 2, and 3 represent the indicated treatments of EGF, DMSO, or gefitinib, respectively. Western blot results of cells from Patient No. 2 and 3 are not shown because similar results were obtained.
Figure 5: GSC model depicting survival of gefitinib treatment. Glioma following the stem cell model contains different subpopulations of tumorigenic (black) and nontumorigenic (white) cells organized in a hierarchy. In this study, the subpopulation of CD133+/EGFRvIII+/EGFR− cells was confirmed to be tumorigenic and regarded as cancer stem-like cells. This subpopulation of cells could survive gefitinib treatment and give rise to phenotypically diverse nontumorigenic cells, while the majority of nontumorigenic glioma cells (CD133−/EGFR+/EGFRvIII+) were killed.
Characteristics of study patients and their tumors according to CD133 and EGFRvIII status
A minority subpopulation of CD133+/EGFRvIII+/EGFR- cells acquires stemness and contributes to gefitinib resistance

April 2013

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48 Reads

To study the contribution of epidermal growth factor receptor variant III (EGFRvIII) to glioblastoma multiforme (GBM) stemness and gefitinib resistance. CD133+ and CD133− cells were separated from EGFRvIII+ clinical specimens of three patients with newly diagnosed GBM. Then, RT-PCR was performed to evaluate EGFRvIII and EGFR expression in CD133+ and CD133− cells. The tumorigenicity and stemness of CD133+ cells was verified by intracranial implantation of 5 × 103 cells into immunodeficient NOD/SCID mice. Finally, cells were evaluated for their sensitivity to EGFR tyrosine kinase inhibition by gefitinib. RT-PCR results showed that the sorted CD133+ cells expressed EGFRvIII exclusively, while the CD133− cells expressed both EGFRvIII and EGFR. At 6–8 weeks postimplantation, CD133+/EGFRvIII+/EGFR− cells formed intracranial tumors. Cell counting kit-8 results showed that the IC50 values of the three isolated EGFRvIII+ cell lines treated with gefitinib were 14.44, 16.00, and 14.66 μM, respectively, whereas the IC50 value of an isolated EGFRvIII− cell line was 8.57 μM. EGFRvIII contributes to the stemness of cancer stem cells through coexpression with CD133 in GBMs. Furthermore, CD133+/EGFRvIII+/EGFR− cells have the ability to initiate tumor formation and may contribute to gefitinib resistance.

Neurocognitive Impairment Across the Bipolar Spectrum

November 2011

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127 Reads

Bipolar disorder is a severe mental illness that affects nearly 4.4% of the general population when bipolar spectrum disorders are taken into account. Neurocognitive impairment is thought to be a core deficit of this illness since it is present during euthymia. In fact, 40-60% of euthymic patients present with neurocognitive disturbances. Not only the clinical factors but also disturbances in neurocognition can influence the functional outcome of BD patients. Hence, further research is needed in order to clarify the relationship between these variables. Despite the growing body of evidence that has emerged during the last decade, no unique neurocognitive profile has been proposed yet for either BD subtype. The majority of the studies recluted heterogeneous samples (including both bipolar I and II) or focused on BD-I patients only. The aim of this review is to give an overall picture of the main neurocognitive disturbances found in the bipolar spectrum and particularly in BD-II, where the findings are more ambiguous. An extensive review of all the literature has been done regarding this subtype (from 1980 until July 2009). Data available until now suggest that deficits are present across the bipolar spectrum (BD-I and BD-II), but they seem slightly more severe in BD-I. The extent to which either subtype share-or not-some similarities is still unknown. More studies are required but it would also be interesting to reach a consensus in the neuropsychological assessment of BD to facilitate comparisons between the different studies.


Ketamine as a Fast Acting Antidepressant: Current Knowledge and Open Questions

April 2013

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101 Reads

Several recent studies have shown that a single intravenous subanesthetic dose of ketamine, a NMDA receptor antagonist, exerts rapid antidepressant effects in patients with treatment refractory mood disorders and reduces suicidal ideation. Those insights have fueled tremendous excitement in the efforts to elucidate the mechanism underlying ketamine's antidepressant properties in animal models of depression, as well as in humans through the use of brain imaging as well as peripheral blood measurements. For example, there is emerging evidence that ketamine's antidepressant properties rely on increasing AMPA signaling and rapidly inducing synaptogenesis. While pilot clinical studies are promising, a number of critical questions still remain unanswered. They relate to the safe and effective use of ketamine in patients with mood disorders regarding the optimal dose range, modality and method of administration for acute and long-term maintenance of effect, and the biomarkers associated with response/nonresponse. In this review article, we first summarize the clinical evidence about the use of ketamine in mood disorders, as well as preclinical and humans studies which investigated the mechanisms of action of ketamine, and predictors of antidepressant response in clinical populations. We then provide a critical overview of the knowledge gaps about the use of ketamine in depression and suggest some future research directions for the investigation of ketamine as a promising tool to develop novel more effective and fast acting antidepressants.

Figure 1: Chemical structure of tolperisone and related compounds.
Tolperisone: A Typical Representative of a Class of Centrally Acting Muscle Relaxants with Less Sedative Side Effects

February 2008

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1,134 Reads

Tolperisone, a piperidine derivative, is assigned to the group of centrally acting muscle relaxants and has been in clinical use now for decades. The review summarizes the known pharmacokinetics, pharmacodynamics, toxicology and side effects in humans and the clinical use of tolperisone. A future perspective for further exploration of this drug is given.

Figure 1: Fasudil delays onset and ameliorates severity of EAE. Fasudil was injected (intraperitoneally) at 40 mg/kg/day every other day on day 3 p.i. (Fasudil early treatment, n = 23) or at onset of clinical symptoms of EAE (Fasudil late treatment, n = 23). The injection of normal saline was set up as control (EAE control, n = 26) in a similar manner. (A) clinical score of EAE mice treated with Fasudil early or late treatment. (B) body weight of EAE mice treated with Fasudil early and late treatment. *P < 0.05; **P < 0.01.
Figure 2: Fasudil inhibits inflammation and improves myelination in spinal cord. On day 21 p.i., spinal cords were used for luxol fast blue, H&E and immunohistochemistry staining. (A) Demyelination stained with luxol fast blue. Total white matter in luxol fast blue was manually outlined, and pixel area (%) of demyelination in total white matter was calculated by Image-Pro Plus software. (B) Inflammation stained with H&E stain. Color photograph in H&E stain was automatically converted to black and white, and a number of inflammatory foci (>20 mononuclear cells/focus) in whole spinal cord were calculated by Image-Pro Plus software. (C) CD4 T cells, CD68 macrophage/microglia and GFAP astrocytes. Quantitative results are analyzed for 6 mice in each group and are representative of three experiments with similar results. *P < 0.05, **P < 0.01.
Fasudil Ameliorates Disease Progression in Experimental Autoimmune Encephalomyelitis, Acting Possibly Through Antiinflammatory Effect

September 2012

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34 Reads

Aim: The purpose of this investigation was to further explore the mechanism(s) underlying the amelioration in EAE caused by Fasudil, particularly focusing on anti-inflammatory effect. Methods: We induced a chronic-progressive experimental autoimmune encephalomyelitis (EAE) in B6 mice immunized with myelin oligodendrocyte glycoprotein(35-55) and performed Fasudil intervention in early and late stages of the disease. Results: The administration of Fasudil (40 mg/kg, i.p) had a therapeutic effect in delaying the onset and ameliorating the severity of EAE, accompanied by the improvement in myelination and the decrease in inflammatory cells in spinal cords. Fasudil inhibited TLR-4, p-NF-kB/p65, and inflammatory cytokines (IL-1β, IL-6, and TNF-α) and enhanced IL-10 production in spinal cords. The ratio of arginase/iNOS was enhanced mainly in the spinal cords of EAE mice treated with Fasudil, reflecting a shift toward the M2 (antiinflammation) macrophage/microglia phenotype. The administration of Fasudil also induced the upregulation of CB2 receptor in spinal cords, but did not significantly trigger CB1 receptor. Levels of neurotrophic factors NGF, BDNF, and GDNF in the CNS were not altered by Fasudil. Conclusion: Fasudil ameliorates disease progression in EAE, acting possibly through antiinflammatory pathway.

The Multiplicity of Action of Cannabinoids: Implications for Treating Neurodegeneration

December 2011

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64 Reads

The cannabinoid (CB) system is widespread in the central nervous system and is crucial for controlling a range of neurophysiological processes such as pain, appetite, and cognition. The endogenous CB molecules, anandamide, and 2-arachidonoyl glycerol, interact with the G-protein coupled CB receptors, CB(1) and CB(2). These receptors are also targets for the phytocannabinoids isolated from the cannabis plant and synthetic CB receptor ligands. The CB system is emerging as a key regulator of neuronal cell fate and is capable of conferring neuroprotection by the direct engagement of prosurvival pathways and the control of neurogenesis. Many neurological conditions feature a neurodegenerative component that is associated with excitotoxicity, oxidative stress, and neuroinflammation, and certain CB molecules have been demonstrated to inhibit these events to halt the progression of neurodegeneration. Such properties are attractive in the development of new strategies to treat neurodegenerative conditions of diverse etiology, such as Alzheimer's disease, multiple sclerosis, and cerebral ischemia. This article will discuss the experimental and clinical evidence supporting a potential role for CB-based therapies in the treatment of certain neurological diseases that feature a neurodegenerative component.

Ang II and Ang IV: Unraveling the Mechanism of Action on Synaptic Plasticity, Memory, and Epilepsy

February 2008

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34 Reads

The central angiotensin system plays a crucial role in cardiovascular regulation. More recently, angiotensin peptides have been implicated in stress, anxiety, depression, cognition, and epilepsy. Angiotensin II (Ang II) exerts its actions through AT(1) and AT(2) receptors, while most actions of its metabolite Ang IV were believed to be independent of AT(1) or AT(2) receptor activation. A specific binding site with high affinity for Ang IV was discovered and denominated "AT(4) receptor". The beneficiary effects of AT(4) ligands in animal models for cognitive impairment and epileptic seizures initiated the search for their mechanism of action. This proved to be a challenging task, and after 20 years of research, the nature of the "AT(4) receptor" remains controversial. Insulin-regulated aminopeptidase (IRAP) was first identified as the high-affinity binding site for AT(4) ligands. Recently, the hepatocyte growth factor receptor c-MET was also proposed as a receptor for AT(4) ligands. The present review focuses on the effects of Ang II and Ang IV on synaptic transmission and plasticity, learning, memory, and epileptic seizure activity. Possible interactions of Ang IV with the classical AT(1) and AT(2) receptor subtypes are evaluated, and other potential mechanisms by which AT(4) ligands may exert their effects are discussed. Identification of these mechanisms may provide a valuable target in the development in novel drugs for the treatment of cognitive disorders and epilepsy.

Comparative Neuroprotective Properties of Stilbene and Catechin Analogs: Action Via a Plasma Membrane Receptor Site?

February 2009

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25 Reads

Various studies have reported on the neuroprotective effects of polyphenols, widely present in food, beverages, and natural products. For example, we have shown that resveratrol, a polyphenol enriched in red wine and other foods such as peanuts, protects hippocampal cells against beta-amyloid (Abeta)-induced toxicity, a key protein involved in the neuropathology of Alzheimer disease. This effect involves, at least in part, the capacity of resveratrol to activate the phosphorylation of delta isoform of protein kinase C (PKC-delta). The neuroprotective action of resveratrol is shared by piceatannol, a stilbene derivative, as well as by tea-derived catechin gallate esters. The thioflavin T assay indicated that all these polyphenols inhibited the formation of Abeta fibrils, suggesting that this action likely also contributes to their neuroprotective effects. Binding and autoradiographic studies revealed that the effects of polyphenols might involve specific binding sites that are particularly enriched in the choroid plexus in the rat brain. Interestingly, the choroid plexus secretes transthyretin, a protein that has been shown to modulate Abeta aggregation and that may be critical to the maintenance of normal learning capacities in aging. Taken together, these data suggest that polyphenols target multiple enzymes/proteins, leading to their neuroprotective actions, possibly through action via specific plasma membrane binding sites.

Anthocyanins Protect against Kainic Acid-induced Excitotoxicity and Apoptosis via ROS-activated AMPK Pathway in Hippocampal Neurons

January 2014

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62 Reads

Excitotoxicity is an important mechanism involved in neurodegeneration. Kainic acid (KA)-induced excitotoxicity results an unfavorable stress, and we investigated the signaling pathways activated in such conditions. Here, we sought to determine the cellular and biochemical benefits of anthocyanins extracted from Korean black bean against KA-induced excitotoxicity and neuronal cell death. Mouse hippocampal cell line (HT22) and primary prenatal rat hippocampal neurons were treated with KA to induce excitotoxicity. Incubation of the cells with KA alone significantly decreased cell viability, elevated intracellular Ca(2+) level, increased generation of reactive oxygen species (ROS) and loss of mitochondrial membrane potential (ΔψM ). These events were accompanied by sustained phosphorylation and activation of AMP-activated protein kinase (AMPK). Kainic acid induced upregulation of Bax, decrease in Bcl-2, release of cytochrome-c, and activation of caspase-3 in both cell types. Anthocyanins attenuated KA-induced dysregulation of Ca(2+,) ROS accumulation, activation of AMPK, and increase in percentage of apoptotic cells. Pretreatment of the cells with compound C, an inhibitor of AMPK, diminished the KA-induced activation of AMPK and caspase-3. The activation of AMPK through elevation of cellular ROS and Ca(2+) levels is required for KA-induced apoptosis in hippocampal neurons. In summary, our data suggest that although anthocyanins have diverse activities, at least part of their beneficial effects against KA-induced hippocampal degeneration can be attributed to their well-recognized antioxidant properties.

Peroxisome Proliferator-activated Receptor-γ Agonist Pioglitazone Ameliorates White Matter Lesion and Cognitive Impairment in Hypertensive Rats

January 2015

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11 Reads

Cerebrovascular white matter lesion (WML) is a major subtype of cerebral small vessel disease. Clinical drugs are not available for WML. We investigated whether peroxisome proliferator-activated receptor-γ agonist pioglitazone, with properties of vascular protection and antiinflammation, exerts beneficial effect in hypertensive WML rats. Stroke-prone renovascular hypertensive rats (RHRSP) were treated with pioglitazone for 12 weeks. Morris water maze experiment was conducted to assess cognition. WML was observed by Luxol fast blue staining. Smooth muscle actin-alpha, collagen I, collagen IV, glial fibrillary acidic protein, and ionized calcium-binding adaptor molecule-1 were evaluated by immunohistochemistry. Interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) in brain and soluble intercellular adhesion molecule-1 (sICAM-1) in serum were detected. Pioglitazone significantly attenuated WML in corpus callosum, caudate putamen, external capsule, and internal capsule. Cognitive impairment in RHRSP was ameliorated by pioglitazone. Pioglitazone attenuated arteriolar remodeling and reduced sICAM-1 level in serum. Pioglitazone decreased the proliferation of microglia and astrocyte and lowered the expression of proinflammatory cytokines IL-1β and TNF-α in the white matter. Long-term treatment of pioglitazone has beneficial effect on hypertension-induced WML and cognition decline, which may partly through its effect on attenuation of arteriolar remodeling, endothelial activation, and brain inflammation. © 2015 John Wiley & Sons Ltd.

Increased Activation of Synapsin 1 and Mitogen‐Activated Protein Kinases/Extracellular Signal‐Regulated Kinase in the Amygdala of Maternal Separation Rats

November 2013

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27 Reads

Early life stress (ELS) causes alterations in emotionality and anxiety levels as a significant risk factor for psychiatric problems, and these alterations have been associated with amygdala activity. To elucidate the molecular mechanism on the development of psychiatric problems following ELS, we identified the alteration of molecules in the amygdala using maternal separation (MS; pnd 14-21) rats through gene expression and DNA methylation microarray analysis, and studied the involvement of candidate genes using a Western blot and immunohistochemistry analysis. Through a microarray analysis, in the amygdala of MS rats, we found a downregulation of mRNA expression of synapsin 1 (Syn1) gene with hypermethylation of its transcription start site (TSS), and the alterations of mRNA expressions of Syn1 activation-related kinase genes including mitogen-activated protein kinases (Mapks) with change of their TSS methylation. In addition, MS increased not only Syn1 phosphorylation at the phosphorylation sites by Mapk/extracellular signal-regulated kinase (Erk), but also Mapk/Erk phosphorylation in the amygdala. Furthermore, double immunofluorescence staining showed that MS could elevate phospho-Mapk/Erk immunoreactivity (IR) in Syn1-expression puncta. These findings indicated that the activation of Mapk/Erk and Syn1 may be a key mechanism modulating synaptic neurotransmition in the amygdala of MS rats.


Table 2 Resting state among healthy participants and patients with Parkinson's Disease (PD) before stimulations and after acupuncture stimulations
Table 3 Higher and lower neural responses among healthy participants before stimulations compared to Parkinson's Disease (PD) before and after acupuncture stimulations
Acupuncture Stimulation on GB34 Activates Neural Responses Associated with Parkinson's Disease

September 2012

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297 Reads

Parkinson's disease (PD) is a degenerative brain disorder that is caused by neural defects in the substantia nigra. Numerous studies have reported that acupuncture treatment on GB34 (Yanglingquan) leads to significant improvements in patients with PD and in PD animal models. Studies using functional magnetic resonance imaging (fMRI) have shown that patients with PD, compared to healthy participants, have lower neural responses in extensive brain regions including the putamen, thalamus, and the supplementary motor area. This study investigated the reported association between acupuncture point GB34 and PD. Using fMRI, neural responses of 12 patients with PD and 12 healthy participants were examined before and after acupuncture stimulation. Acupuncture stimulation increased neural responses in regions including the substantia nigra, caudate, thalamus, and putamen, which are impaired caused by PD. Areas associated with PD were activated by the acupuncture stimulation on GB34. This shows that acupuncture treatment on GB34 may be effective in improving the symptoms of PD. Although more randomized controlled trials on the topic will be needed, this study shows that acupuncture may be helpful in the treatment of symptoms involving PD.


Resveratrol Protects Vascular Endothelial Cells from High Glucose–Induced Apoptosis through Inhibition of NADPH Oxidase Activation–Driven Oxidative Stress

June 2013

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Hyperglycemia-induced oxidative stress has been implicated in diabetic vascular complications in which NADPH oxidase is a major source of reactive oxygen species (ROS) generation. Resveratrol is a naturally occurring polyphenol, which has vasoprotective effects in diabetic animal models and inhibits high glucose (HG)–induced oxidative stress in endothelial cells. We aimed to examine whether HG-induced NADPH oxidase activation and ROS production contribute to glucotoxicity to endothelial cells and the effect of resveratrol on glucotoxicity. Using a murine brain microvascular endothelial cell line bEnd3, we found that NADPH oxidase inhibitor (apocynin) and resveratrol both inhibited HG-induced endothelial cell apoptosis. HG-induced elevation of NADPH oxidase activity and production of ROS were inhibited by apocynin, suggesting that HG induces endothelial cell apoptosis through NADPH oxidase–mediated ROS production. Mechanistic studies revealed that HG upregulated NADPH oxidase subunit Nox1 but not Nox2, Nox4, and p22phox expression through NF-κB activation, which resulted in elevation of NADPH oxidase activity and consequent ROS production. Resveratrol prevented HG-induced endothelial cell apoptosis through inhibiting HG-induced NF-κB activation, NADPH oxidase activity elevation, and ROS production. HG induces endothelial cell apoptosis through NF-κB/NADPH oxidase/ROS pathway, which was inhibited by resveratrol. Our findings provide new potential therapeutic targets against brain vascular complications of diabetes.

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