Symptoms In Animal Models Research Articles

Systemically administered human bone marrow-derived mesenchymal stem home into peripheral organs but do not induce neuroprotective effects in the MCAo-mouse model for cerebral ischemia

Mesenchymal stem cells (MSC) from bone marrow induce neuroprotective effects and improve clinical symptoms in animal models for acute cerebral ischemia. So far only few data are available from the murine system. Moreover, no data exist regarding neuroprotective effects depending on the application route. Because most preclinical trials regarding restorative therapy in stroke are performed in mice, we aimed to investigate the neuroprotective capacities of human MSC (hMSC) in the middle cerebral artery occlusion (MCAo)-mouse model of cerebral ischemia. As systemic transplantation of MSC could provide a gentle therapeutic procedure for the (mostly elderly) stroke patients, we analyzed effects of this application at a clinically relevant time point. Bone marrow-derived hMSCs were administered intravenously 24h after MCAo. Mortality and clinical outcome of the transplanted mice did not differ from PBS-treated controls. After 3 and 7 days hMSC were robustly detected in lung, spleen, kidney and intestine, but not in the brain. MRI measurements revealed no differences in infarct size in hMSC injected animals compared to controls. In the neurogenic subventricular zone and the dentate gyrus no significant increase of endogenous cell proliferation was detected following systemic hMSC transplantation. This data further prove the week neurogenic and neuroprotective effect and the limitations of systemically administered hMSCs in cerebral ischemia.

Expression of retinoid X receptor beta is induced in astrocytes during corpus callosum demyelination

The experimental activation of retinoid receptors reduces pathological symptoms in animal models of multiple sclerosis. In order to assess the involvement of endogenous retinoid signaling during the process of demyelination we investigated retinoic acid synthesizing enzymes and nuclear receptors using the mouse model of cuprizone toxicity. The initiation of myelin degradation in the corpus callosum was accompanied with a local increase of retinaldehyde dehydrogenase (RALDH) immunoreactivity. On the level of receptors we observed a striking increase in protein expression of the retinoid X receptor (RXR)-β in the affected corpus callosum. The RXRβ immunoreactivity appeared exclusively in astrocytes, where it reached a maximum at five weeks of treatment, following the RALDH response. In the cerebral cortex and basal ganglia of affected mice RXRβ was also observed in neurons. Among nuclear receptor antigens RARα showed a cuprizone associated increase in the corpus callosum. Quantitative RT-PCR revealed strong basal expression of RXRβ and a significant, over 20-fold upregulation of the peroxisome proliferator-activated receptor-γ during demyelination. The results indicate that compensatory mechanisms during central demyelination may engage nuclear receptor dimers with an RXRβ partner.

Perampanel in Parkinson Disease Fluctuations

Perampanel is a selective and noncompetitive α-amino-3-hydroxy-5-methylisoxazole propionic acid-type glutamate receptor antagonist that improves motor symptoms in animal models of Parkinson disease (PD). The aim of this study was to assess the efficacy and tolerability of perampanel in L-dopa-treated patients with moderately severe PD and motor fluctuations using an active comparator study design. This was a prospective, randomized, double-blind, 3-arm, parallel-group, controlled study assessing the effects of perampanel (4 mg/d), placebo, or entacapone (200 mg with each dose of L-dopa) in 723 L-dopa-treated patients with PD with "OFF" problems. The primary outcome measure was the change from baseline in mean total daily OFF time based on diaries. Secondary end points included change from baseline in Unified Parkinson's Disease Rating Scale part II while OFF, Unified Parkinson's Disease Rating Scale part III while "ON," and mean total daily ON time without dyskinesias or with nontroublesome dyskinesias. In total, 480 patients (66.4%) completed the study, which was terminated early after negative results of 2 other large placebo-controlled studies became available. Perampanel was not superior to placebo on any efficacy end point, whereas entacapone was superior to placebo on the primary end point (P = 0.034) and most secondary outcomes. Perampanel was generally well tolerated. Perampanel (4 mg/d) was well tolerated but did not have a clinically significant effect in improving motor symptoms of L-dopa-treated patients with moderately advanced PD and motor fluctuations. These patients did respond to the active comparator, entacapone, confirming the validity of the findings despite the early termination of the study.

Intracerebral adult stem cells transplantation increases brain-derived neurotrophic factor levels and protects against phencyclidine-induced social deficit in mice

Stem cell-based regenerative therapy is considered a promising cellular therapeutic approach for the patients with incurable brain diseases. Mesenchymal stem cells (MSCs) represent an attractive cell source for regenerative medicine strategies for the treatment of the diseased brain. Previous studies have shown that these cells improve behavioral deficits in animal models of neurological disorders such as Parkinson's and Huntington's diseases. In the current study, we examined the capability of intracerebral human MSCs transplantation (medial pre-frontal cortex) to prevent the social impairment displayed by mice after withdrawal from daily phencyclidine (PCP) administration (10 mg kg−1 daily for 14 days). Our results show that MSCs transplantation significantly prevented the PCP-induced social deficit, as assessed by the social preference test. In contrast, the PCP-induced social impairment was not modified by daily clozapine treatment. Tissue analysis revealed that the human MSCs survived in the mouse brain throughout the course of the experiment (23 days). Significantly increased cortical brain-derived neurotrophic factor levels were observed in the MSCs-treated group as compared with sham-operated controls. Furthermore, western blot analysis revealed that the ratio of phosphorylated Akt to Akt was significantly elevated in the MSCs-treated mice compared with the sham controls. Our results demonstrate that intracerebral transplantation of MSCs is beneficial in attenuating the social deficits induced by sub-chronic PCP administration. We suggest a novel therapeutic approach for the treatment of schizophrenia-like negative symptoms in animal models of the disorder.

Turning skin into dopamine neurons

Turning skin into dopamine neurons

Protecting the Protector

Targeting a metabolic enzyme in blood protects neurons in the brain and ameliorates symptoms in animal models of Alzheimer’s and Huntington’s disease.

Memantine reduces mania-like symptoms in animal models

Memantine, a selective antagonist of the N-methyl-D-aspartate receptor, is approved for the treatment of moderate to severe Alzheimer's disease. Ion dysregulation is thought to be involved in the pathophysiology of bipolar illness, suggesting that memantine may be effective in treating bipolar manic and/or depressive episodes. We utilized two preclinical models of mania that mimic pathophysiologic changes seen in bipolar illness to examine the potential efficacy of memantine in the treatment of this disorder. Locomotor hyperactivity of male Sprague–Dawley rats in an open field was induced with intracerebroventricular (ICV) administration of 10−3 M ouabain. Memantine (2.5, 5 or 7.5mg/kg), lithium (6.75mEq/kg), or vehicle were administered acutely via intraperitoneal injection immediately prior to ouabain, then chronically for 7days (oral memantine 20, 30, and 40mg/kg/day in water; lithium 2.4g/kg food). In a second model of bipolar disorder, cycling between population spikes and epileptiform bursts was investigated in rat hippocampal slices treated with ouabain (3.3μM) alone or in combination with memantine (0.5, 1.0, and 5.0μM). Ouabain-induced hyperlocomotion was normalized with acute and chronic lithium and chronic use of memantine. Memantine delayed the onset of ouabain-induced-cycling in hippocampal slices. Memantine may have antimanic properties.

Studies on the origin of non-specific symptoms attributed to exposure to power frequency electromagnetic fields.

Event Abstract Back to Event Studies on the origin of non-specific symptoms attributed to exposure to power frequency electromagnetic fields. O. Drozdovszky1, R. Szemerszky2, F. Köteles2 and G. Bárdos1, 2* 1 Eötvös Loránd University, Department of Physiology and Neurobiology, Hungary 2 Eötvös Loránd University, Institute for Health Promotion and Sport Sciencies, Hungary Although the adverse effects of the non-ionizing electromagnetic fields (EMFs) have not been proven, there are frequent complaints about non-specific symptoms (e.g. headache, dizziness, sleeping disturbances, etc.) attributed to EMF exposure. Our aim was to study the influence of psychological factors (e.g. negative expectancies, worrying about EMF) as well as direct biological effects of EMF exposure on the complaints. In animal experiments, male and female Wistar rat embrios or pups, respectively, had been exposed to an EMF of 50 Hz, 0.5 mT for 168 hours and were examined later in 3 different behavioral tests (locomotor activity, Elevated Plus Maze, Social Avoidance). In another, human study, 72 volunteers filled up symptom expectancy and modern health worries /MHW/ questionnaires, then put one hand between two active electromagnetic coils and were asked to mark experienced items from a list of 19 somatic symptoms. Although some minor effects following EMF exposure in the animal experiments have been found, the changes were small and inconsistent. In other words, we could not reproduce the human symptoms in animal models thus their biological origin has still remained questionable. In the human study, those participants experienced more symptoms during the exposure who had shown more symptom expectancies (r=0,54; p<0,000) and increased worries (r=0,25; p=0,035), proving that psychological factors may really affect and enchace EMF-induced symptom perception. Keywords: Behaviour and cognition, Neuroscience Conference: 13th Conference of the Hungarian Neuroscience Society (MITT), Budapest, Hungary, 20 Jan - 22 Jan, 2011. Presentation Type: Abstract Topic: Behaviour and cognition Citation: Drozdovszky O, Szemerszky R, Köteles F and Bárdos G (2011). Studies on the origin of non-specific symptoms attributed to exposure to power frequency electromagnetic fields.. Front. Neurosci. Conference Abstract: 13th Conference of the Hungarian Neuroscience Society (MITT). doi: 10.3389/conf.fnins.2011.84.00110 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 03 Mar 2011; Published Online: 23 Mar 2011. * Correspondence: Dr. G. Bárdos, Eötvös Loránd University, Department of Physiology and Neurobiology, Budapest, Hungary, bardosgy@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers O. Drozdovszky R. Szemerszky F. Köteles G. Bárdos Google O. Drozdovszky R. Szemerszky F. Köteles G. Bárdos Google Scholar O. Drozdovszky R. Szemerszky F. Köteles G. Bárdos PubMed O. Drozdovszky R. Szemerszky F. Köteles G. Bárdos Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Tetanus Toxin C-Fragment: The Courier and the Cure?

In many neurological disorders strategies for a specific delivery of a biological activity from the periphery to the central nervous system (CNS) remains a considerable challenge for successful therapy. Reporter assays have established that the non-toxic C-fragment of tetanus toxin (TTC), provided either as protein or encoded by non-viral naked DNA plasmid, binds pre-synaptic motor neuron terminals and can facilitate the retrograde axonal transport of desired therapeutic molecules to the CNS. Alleviated symptoms in animal models of neurological diseases upon delivery of therapeutic molecules offer a hopeful prospect for TTC therapy. This review focuses on what has been learned on TTC-mediated neuronal targeting, and discusses the recent discovery that, instead of being merely a carrier molecule, TTC itself may well harbor neuroprotective properties.

Safety and efficacy of perampanel in advanced Parkinson's disease: A randomized, placebo-controlled study

Perampanel, a novel, noncompetitive, selective AMPA-receptor antagonist demonstrated evidence of efficacy in reducing motor symptoms in animal models of Parkinson's disease (PD). We assessed the safety and efficacy of perampanel for treatment of "wearing off" motor fluctuations in patients with PD. Patients (N = 263) were randomly assigned to once-daily add-on 0.5, 1, or 2 mg of perampanel or placebo. The primary objective was to determine whether there was a dose-response relationship for efficacy among the 3 perampanel doses and placebo. The primary efficacy endpoint for each treatment was measured as the least-squares (LS) mean change from baseline to week 12 in percent "off" time reduction during the waking day, as recorded by patient diaries. The primary efficacy analysis was a 1-sided Williams test for dose-response trend at the 0.025 level of significance. At week 12, dose-response trends, as determined by the Williams test, were not statistically significant for LS mean reduction in percent "off" time during the waking day (P = 0.061, with significance defined as P <or= 0.025). The 2 higher perampanel doses (ITT population; n = 258) produced nonsignificant reductions from baseline to week 12 in percent "off" time during the waking day versus placebo (7.59%, P= 0.421 [1 mg], 8.60%, P = 0.257 [2 mg] versus 5.05% [placebo]; significance for pairwise comparisons defined as P <or= 0.05). There were no significant changes in dyskinesia or cognitive function in any perampanel group versus placebo. Adverse events were similar across treatment groups. Perampanel treatment was well tolerated and safe, but failed to achieve statistical significance in primary and secondary endpoints.

Parkinson's disease: From pathophysiology to new therapeutical approaches

Event Abstract Back to Event Parkinson's disease: From pathophysiology to new therapeutical approaches Abdelhamid Benazzouz1* 1 CNRS UMR 5227, Laboratoire MAC, France Parkinson’s disease (PD) is neurodegenerative disorder characterized by the manifestation of three cardinal motor symptoms: akinesia, rigidity and rest tremor. These symptoms are the consequence of a progressive degeneration of dopamine neurons in the pars compacta of substantia nigra, which results in a depletion of dopamine in the striatum and other brain structures. Functionally, the depletion of dopamine induces a disorganization of the neuronal activity in basal ganglia nuclei and especially in the subthalamic nucleus (STN), which plays a key role in the control of movement. Several studies in rodent and non human primate models of PD have shown that the depletion of dopamine induced dramatic changes in the discharge pattern of STN neurons. The regular activity recorded in the normal situation was replaced by bursty and irregular pattern of activity, in the pathological situation. During the last two decades, deep brain stimulation (DBS) of the STN has proven to be highly effective in reducing all the cardinal motor symptoms in animal models of the disease as well as in parkinsonian patients suffering from a severe form of PD. However, despite these clinical achievements, the precise action mechanisms of STN-DBS still need to be fully characterized at molecular and cellular level. Our experimental studies have suggested that STN-DBS, at parameters improving motor symptoms, reduced the abnormal hyperactivity of STN neurons. Recently, DBS of other brain regions has proven to be capable of providing significant benefits for several complex motor neuropathologies as essential tremor and dystonia, and also some pharmaco-resistant psychiatric disorders such as Tourette syndrome, obsessive-compulsive disorder and severe depression. Conference: 2nd NEUROMED Workshop, Fez, Morocco, 10 Jun - 12 Jun, 2010. Presentation Type: Oral Presentation Topic: Oral Session 1: Brain diseases and their treatment Citation: Benazzouz A (2010). Parkinson's disease: From pathophysiology to new therapeutical approaches. Front. Neurosci. Conference Abstract: 2nd NEUROMED Workshop. doi: 10.3389/conf.fnins.2010.12.00003 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 03 Jun 2010; Published Online: 03 Jun 2010. * Correspondence: Abdelhamid Benazzouz, CNRS UMR 5227, Laboratoire MAC, Bordeaux, France, Abdelhamid.Benazzouz@u-bordeaux2.fr Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Abdelhamid Benazzouz Google Abdelhamid Benazzouz Google Scholar Abdelhamid Benazzouz PubMed Abdelhamid Benazzouz Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Vertebrate Endoderm Development and Organ Formation

The endoderm germ layer contributes to the respiratory and gastrointestinal tracts and to all of their associated organs. Over the past decade, studies in vertebrate model organisms, including frog, fish, chick, and mouse, have greatly enhanced our understanding of the molecular basis of endoderm organ development. We review this progress with a focus on early stages of endoderm organogenesis including endoderm formation, gut tube morphogenesis and patterning, and organ specification. Lastly, we discuss how developmental mechanisms that regulate endoderm organogenesis are used to direct differentiation of embryonic stem cells into specific adult cell types, which function to alleviate disease symptoms in animal models.

Microglial CB2 cannabinoid receptors are neuroprotective in Huntington's disease excitotoxicity

Cannabinoid-derived drugs are promising agents for the development of novel neuroprotective strategies. Activation of neuronal CB(1) cannabinoid receptors attenuates excitotoxic glutamatergic neurotransmission, triggers prosurvival signalling pathways and palliates motor symptoms in animal models of neurodegenerative disorders. However, in Huntington's disease there is a very early downregulation of CB(1) receptors in striatal neurons that, together with the undesirable psychoactive effects triggered by CB(1) receptor activation, foster the search for alternative pharmacological treatments. Here, we show that CB(2) cannabinoid receptor expression increases in striatal microglia of Huntington's disease transgenic mouse models and patients. Genetic ablation of CB(2) receptors in R6/2 mice, that express human mutant huntingtin exon 1, enhanced microglial activation, aggravated disease symptomatology and reduced mice lifespan. Likewise, induction of striatal excitotoxicity in CB(2) receptor-deficient mice by quinolinic acid administration exacerbated brain oedema, microglial activation, proinflammatory-mediator state and medium-sized spiny neuron degeneration. Moreover, administration of CB(2) receptor-selective agonists to wild-type mice subjected to excitotoxicity reduced neuroinflammation, brain oedema, striatal neuronal loss and motor symptoms. Studies on ganciclovir-induced depletion of astroglial proliferation in transgenic mice expressing thymidine kinase under the control of the glial fibrillary acidic protein promoter excluded the participation of proliferating astroglia in CB(2) receptor-mediated actions. These findings support a pivotal role for CB(2) receptors in attenuating microglial activation and preventing neurodegeneration that may pave the way to new therapeutic strategies for neuroprotection in Huntington's disease as well as in other neurodegenerative disorders with a significant excitotoxic component.

Vitamin D, a neuro-immunomodulator: Implications for neurodegenerative and autoimmune diseases

It has been known for more than 20 years that vitamin D exerts marked effects on immune and neural cells. These non-classical actions of vitamin D have recently gained a renewed attention since it has been shown that diminished levels of vitamin D induce immune-mediated symptoms in animal models of autoimmune diseases and is a risk factor for various brain diseases. For example, it has been demonstrated that vitamin D (i) modulates the production of several neurotrophins, (ii) up-regulates Interleukin-4 and (iii) inhibits the differentiation and survival of dendritic cells, resulting in impaired allo-reactive T cell activation. Not surprisingly, vitamin D has been found to be a strong candidate risk-modifying factor for Multiple Sclerosis (MS), the most prevalent neurological and inflammatory disease in the young adult population. Vitamin D is a seco-steroid hormone, produced photochemically in the animal epidermis. The action of ultraviolet light (UVB) on 7-dehydrocholesterol results in the production of pre-vitamin D which, after thermo-conversion and two separate hydroxylations, gives rise to the active 1,25-dihydroxyvitamin D. Vitamin D acts through two types of receptors: (i) the vitamin D receptor (VDR), a member of the steroid/thyroid hormone superfamily of transcription factors, and (ii) the MARRS (membrane associated, rapid response steroid binding) receptor, also known as Erp57/Grp58. In this article, we review some of the mechanisms that may underlie the role of vitamin D in various brain diseases. We then assess how vitamin D imbalance may lay the foundation for a range of adult disorders, including brain pathologies (Parkinson's disease, epilepsy, depression) and immune-mediated disorders (rheumatoid arthritis, type I diabetes mellitus, systemic lupus erythematosus or inflammatory bowel diseases). Multidisciplinary scientific collaborations are now required to fully appreciate the complex role of vitamin D in mammal metabolism.

Role of Calcitonin Gene-Related Peptide in Light-Aversive Behavior: Implications for Migraine

Migraine is a chronic neurological disorder characterized by recurrent episodes of severe unilateral throbbing head pain and associated symptoms, such as photophobia. Our current understanding of the mechanisms underlying migraine has been hampered by limitations in ascertaining migraine symptoms in animal models. Clinical studies have established the neuropeptide calcitonin gene-related peptide (CGRP) as a key player in migraine. Here, we establish a genetic model of photophobia by engineering increased sensitivity to CGRP in mice. These transgenic mice (nestin/hRAMP1) display light-aversive behavior that is greatly enhanced by intracerebroventricular injection of CGRP and blocked by coadministration of the CGRP receptor antagonist olcegepant. This behavior appears to be an indicator of photophobia and cannot be fully explained by gross abnormality of ocular anatomy or differences in general anxiety or motor activity. Our findings demonstrate that a single gene, receptor activity-modifying protein 1 (RAMP1), can be a modifier of photophobia and, by extension, suggest that genetic or epigenetic modulation of RAMP1 levels may contribute to migraine susceptibility. Moreover, they validate CGRP hypersensitive mice as a tool for exploring the neurobiology and novel therapies for migraine and other disorders involving photophobia.

In vivo PET studies in non-human primate model of neuropsychiatric disorders and neurodegenerative diseases: the differences between macaques and marmosets

We evaluated correlation between neurochemical and functional alterations of the nigrostriatal dopaminergic system in rat brains lesioned with 6-hydroxydopamine (6-OHDA), that model hemi-Parkinson's disease (PD), by using three different quantitative in vivo and in vitro methods. Rats unilaterally lesioned with different doses of 6-OHDA underwent two types of in vivo experiments: (1) a rotational behavioral study with methamphetamine (MAP) or apomorphine (APO); and (2) a positron emission tomography (PET) study with [11C]PE2I (radioligand for dopamine transporters) or [11C]raclopride (radioligand for dopamine D2 receptors). An in vitro autoradiographic study with the same radioligands was also conducted. The number of rotations after the MAP or APO injection increased with increased doses of 6-OHDA. The in vitro and in vivo binding of [11C]PE2I dose-dependently decreased in response to the 6-OHDA injections, while that of [11C]raclopride dose-dependently increased. There was a significant negative hyperbolic correlation between the number of rotations after MAP injection and the binding of [11C]PE2I. In contrast, there was a significant positive linear correlation between the number of rotations after APO injections and the binding of [11C]raclopride. These results robustly reveal a molecular pharmacological basis of parkinsonian symptoms in animal models of PD, and indicate the utility and validity of in vivo PET measurements in assessing pre- and post-synaptic dopaminergic functions.

Metabotropic Glutamate Receptors 5 Blockade Reverses Spatial Memory Deficits in a Mouse Model of Parkinson's Disease

Visuo-spatial deficits are the most consistently reported cognitive abnormalities in Parkinson's disease (PD), and they are frequently associated to motor symptoms in the early stages of the disease when dopamine loss is moderate and still restricted to the caudate-putamen. The metabotropic glutamate receptor 5 (mGluR5) antagonist, 2-methyl-6-(phenylethynyl)-pyridine (MPEP), has beneficial effects on motor symptoms in animal models of PD. However, the effects of MPEP on the cognitive deficits of the disease have never been investigated. Thus, the purpose of this study was to explore its therapeutic potentials by investigating its effects on the visuo-spatial deficits induced by 6-hydroxydopamine (6-OHDA) lesions of dorsal striatum in CD1 mice. The results demonstrated that systemic injections of MPEP (6, 12, and 24 mg/kg, i.p.) impair visuo-spatial discrimination in intact mice at high concentrations, whereas lower doses (1.5 and 3 mg/kg, i.p.) were void of effects. Nevertheless, when an ineffective dose (MPEP 3 mg/kg) was injected, either acutely or subchronically (8 days), it antagonized the visuo-spatial discrimination deficit induced by bilateral dopamine lesion of the striatum. Furthermore, the same treatment increased contralateral turning induced by L-DOPA in mice bearing unilateral 6-OHDA lesion. These results confirm the therapeutic potential of mGluR5 blockade on motor symptoms induced by reduced striatal dopamine function. Further, they demonstrate that mGluR5 blockade may also have beneficial effects on cognitive deficits induced by dopamine depletion.

Mode of cell death in C6 glial cell exposed to 1‐methyl‐4‐phenylpyridinum (MPP+)

1‐methyl‐4‐phenylpyridinum (MPP+) is shown to cause selective death of nigrostriatal dopaminergic neurons in the brain, and is widely employed to induce Parkinson's disease symptoms in animal models. The present study was designed to examine if MPP+‐induced astrogliosis is related to apoptosis or necrosis in presence of 2 or 10 mM D‐glucose by using flowcytometry. For this purpose, the C6 glial cell line was used as an in vitro model to assess the MPP+‐induced astrogliosis by testing at 10, 30, 50, 70, 90, 100, 150, 250, 500 and 1000 μM for 12 h. The treated cells were stained with annexin V and propidium iodide (PI) and analyzed by flowcytometry within 1 h to assess the mode of cell death. In order to investigate the effect of MPP+on cell cycle stages, the rat C6 glial cells were treated with MPP+ at 100, 150, 250, 500 and 1000 μM for 12 h in the presence of 2 or 10 mM D‐glucose. These cells were stained with PI and analyzed by flow‐cytometry. The data indicate that exposure with MPP+ at 100 μM or above caused necrotic cell death predominantly when cells were grown in 2 mM D‐glucose, while MPP+atlower concentrations of 10, 30, 50, 70 and 90 μM caused significantly higher apoptotic cell death than necrotic. Interestingly, D‐glucose at 10 mM not only decreased the number of cells undergoing necrosis caused by MPP+ at 100 μM or higher but also increased the number of live cells at these concentrations. Cell cycle analysis indicate that glial cells in 2 mM D‐glucose were marginally (&lt; 12%) arrested at G1 stage with 1000 μM MPP+, while 10 mM D‐glucose decreased the percentage of cell arrest (&lt; 6%) with 1000 μM MPP+. Moreover, the cell cycle results confirm the protective role of D‐glucose against MPP+toxicity. (Supported by NIH Grant RR03020)

Hofmeister Salts and Potential Therapeutic Compounds Accelerate in Vitro Fibril Formation of the N-Terminal Domain of PABPN1 Containing a Disease-Causing Alanine Extension

The analysis of modulation of fibril formation helps to understand the mechanism of fibrillation processes besides opening routes for therapeutic intervention. Fibril formation was investigated with the N-terminal domain of the nuclear poly-A binding protein PABPN1, a protein in which mutation-based alanine extensions lead to the disease oculopharyngeal muscular dystrophy (OPMD). The disease is characterized by fibrillar inclusions consisting mainly of PABPN1. A systematic modulation of fibril formation kinetics was studied with trifluoroethanol, inorganic salts, low molecular weight organic substances, a poly-alanine peptide and anti-amyloidogenic compounds. Anions with salting out properties at high molar concentrations, poly-ethylene glycol and the poly-alanine peptide enhanced fibril formation rates. The effect of l-arginine on fibrillation rates depended on the counterion. Doxycycline and trehalose, compounds that have been found to mitigate OPMD symptoms in animal models, surprisingly accelerated fibril formation. Our results suggest that in the case of salts, primarily the salting out effects rather than electrostatic effects modulate fibril formation. The unexpected acceleration of fibril formation by trehalose and doxycycline questions the general view that these compounds per se impair fibril formation.

Subcutaneous Peripheral Injection of Cationized Gelatin/DNA Polyplexes As a Platform for Non-viral Gene Transfer to Sensory Neurons

Selective modulation of sensory neuron gene expression could have numerous applications for the peripheral nervous system. Here, we report that subcutaneous peripheral injection of plasmid DNA complexed with a non-viral cationized gelatin (CG) vector led to transgene expression in rat lumbar dorsal root ganglia (DRGs). CG/DNA polyplexes appeared to undergo rapid retrograde transport through sciatic and spinal nerves, with reporter gene messenger RNA (mRNA) expression detectable in L4 and L5 DRGs within 60 hours. Maximum transgene expression was observed for polyplexes formed at 7.5:1 CG-to-DNA weight ratio under salt-free conditions, which generated 615 +/- 112 nm nanoparticles with zeta-potential of 9.4 +/- 0.19 mV. Six days after injection of the CG/DNA polypex, reporter gene protein immunofluorescence was observed in 1,164 +/- 176 DRG neurons, representing an estimated transfection rate of 47% of targeted neurons. Reporter gene expression was not detected in heart, lung, or liver tissues, suggesting a lack of systemic uptake. Measurements of tactile sensitivity indicate that CG/DNA injection did not cause behavioral toxicity. The injection platform was further used for plasmid-driven short hairpin RNA-mediated suppression of glyceraldehyde-3-phosphate dehydrogenase. This non-invasive gene delivery system could be used for the mechanistic study and targeted molecular evaluation of peripheral nervous system pathologies such as neuropathic pain.