Cellular and Molecular Neurobiology (CELL MOL NEUROBIOL)

Publications in this journal

• Article: Immunocytochemical Localization of TASK-3 (K2P9.1) Channels in Monoaminergic and Cholinergic Neurons

  Christiane Marinc, Regina Preisig-Müller, Harald Prüss, Christian Derst, Rüdiger W. Veh
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  ABSTRACT: Monoaminergic and cholinergic systems are important regulators of cortical and subcortical systems, and a variety of vegetative functions are controlled by the respective neurotransmitters. Neuronal excitability and transmitter release of these neurons are strongly regulated by their potassium conductances carried by Kir and K2P channels. Here we describe the generation and characterization of a polyclonal monospecific antibody against rat TASK-3, a major brain K2P channel. After removal of cross-reactivities and affinity purification the antibody was characterized by ELISA, immunocytochemistry of TASK-3 transfected cells, and Western blots indicating that the antibody only detects TASK-3 protein, but not its paralogs TASK-1 and TASK-5. Western blot analysis of brain membrane fractions showed a single band around 45kD, close to the predicted molecular weight of the TASK-3 protein. In addition, specific immunolabeling using the anti-TASK-3 antibody in Western blot analysis and immunocytochemistry was blocked in a concentration dependent manner by its cognate antigen only. Immunocytochemical analysis of rat brain revealed strong expression of TASK-3 channels in serotoninergic neurons of the dorsal and median raphe, noradrenergic neurons of the locus coeruleus, histaminergic neurons of the tuberomammillary nucleus and in the cholinergic neurons of the basal nucleus of Meynert. Immunofluorescence double-labeling experiments with appropriate marker enzymes confirmed the expression of TASK-3 in cholinergic, serotoninergic, and noradrenergic neurons. In the dopaminergic system strong TASK-3 expression was found in the ventral tegmental area, whereas TASK-3 immunoreactivity in the substantia nigra compacta was only weak. All immunocytochemical results were supported by in situ hybridization using TASK-3 specific riboprobes. KeywordsK2P channel–Tandem pore domain–TASK–Dopamine–Acetylcholine
  Cellular and Molecular Neurobiology 04/2012; 31(2):323-335.
• Article: Neuroscience and Brain Injury

  Vladimír Štrbák
  Cellular and Molecular Neurobiology 04/2012;
• Article: Angiotensin II AT1 Receptor Blockers Ameliorate Inflammatory Stress: A Beneficial Effect for the Treatment of Brain Disorders

  Juan M. Saavedra
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  ABSTRACT: Excessive allostatic load as a consequence of deregulated brain inflammation participates in the development and progression of multiple brain diseases, including but not limited to mood and neurodegenerative disorders. Inhibition of the peripheral and brain Renin–Angiotensin System by systemic administration of Angiotensin II AT1 receptor blockers (ARBs) ameliorates inflammatory stress associated with hypertension, cold-restraint, and bacterial endotoxin administration. The mechanisms involved include: (a) decreased inflammatory factor production in peripheral organs and their release to the circulation; (b) reduced progression of peripherally induced inflammatory cascades in the cerebral vasculature and brain parenchyma; and (c) direct anti-inflammatory effects in cerebrovascular endothelial cells, microglia, and neurons. In addition, ARBs reduce bacterial endotoxin-induced anxiety and depression. Further pre-clinical experiments reveal that ARBs reduce brain inflammation, protect cognition in rodent models of Alzheimer’s disease, and diminish brain inflammation associated with genetic hypertension, ischemia, and stroke. The anti-inflammatory effects of ARBs have also been reported in circulating human monocytes. Clinical studies demonstrate that ARBs improve mood, significantly reduce cognitive decline after stroke, and ameliorate the progression of Alzheimer’s disease. ARBs are well-tolerated and extensively used to treat cardiovascular and metabolic disorders such as hypertension and diabetes, where inflammation is an integral pathogenic mechanism. We propose that including ARBs in a novel integrated approach for the treatment of brain disorders such as depression and Alzheimer’s disease may be of immediate translational relevance. KeywordsBrain Renin–Angiotensin system–Angiotensin II AT1 receptor blockers–Stress–Brain inflammation–Depression–Anxiety–Mood disorders–Neurodegenerative disorders–Alzheimer’s disease–Stroke–Cognition
  Cellular and Molecular Neurobiology 04/2012;
• Article: Increase of CGRP Expression in Motor Endplates Within Fore and Hind Limb Muscles of the Degenerating Muscle Mouse (Scn8admu)

  Tadasu Sato, Yoshinaka Shimizu, Mitsuhiro Kano, Toshihiko Suzuki, Hiroyasu Kanetaka, Leona W. G. Chu, Patrice D. Côté, Hidetoshi Shimauchi, Hiroyuki Ichikawa
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  ABSTRACT: The distribution of calcitonin gene-related peptide (CGRP) was examined in skeletal muscles of fore and hind limb as well as in oral and cranio-facial regions of the degenerating muscle (dmu) mouse, which harbours a null mutation in the voltage-gated sodium channel gene Scn8a. In limb, oral and cranio-facial muscles of wild type mice, only a few motor endplates contained CGRP-immunoreactivity. However, many CGRP-immunoreactive motor endplates appeared in the triceps brachii muscle, the biceps brachii muscle, the brachialis muscle, and the gastrocnemius muscle of dmu mice. CGRP-immunoreactive density of motor endplates in the skeletal muscles was also elevated by the mutation. In these muscles, the atrophy of muscle fibers could be detected and the density of cell nuclei in the musculature increased. In the flexor digitorum profundus muscle, the flexor digitorum superficialis muscle, and the soleus muscle as well as in oral and cranio-facial muscles, however, the distribution of CGRP-immunoreactivity was barely affected by the mutation. The morphology of muscle fibers and the distribution of cell nuclei within them were also similar in wild type and dmu mice. In the lumbar spinal cord of dmu mice, CGRP-immunoreactive density of spinal motoneurons increased. These findings suggest that the atrophic degeneration in some fore and hind limb muscles of dmu mice may increase CGRP expression in their motoneurons. KeywordsCalcitonin gene-related peptide– dmu mouse–Motoneuron–Spinal cord–Immunohistochemistry– Scn8a
  Cellular and Molecular Neurobiology 04/2012; 31(1):155-161.
• Article: Expressions of per1 Clock Gene and Genes of Signaling Peptides Vasopressin, Vasoactive Intestinal Peptide, and Oxytocin in the Suprachiasmatic and Paraventricular Nuclei of Hypertensive TGR[mREN2]27 Rats

  Zuzana Dzirbíková, Alexander Kiss, Monika Okuliarová, Libor Kopkan, Luděk Červenka, Michal Zeman
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  ABSTRACT: Hypertensive rats with multiple extra copies of the renin gene (TGR) exert an inverted circadian blood pressure (BP) profile. We investigated whether circadian oscillations in the hypothalamic suprachiasmatic nucleus (SCN), a main circadian oscillator, and the paraventricular nucleus (PVN), involved in BP control, are influenced in TGR rats. The expression of the clock gene per1, a marker of circadian timing, was measured in the SCN and PVN. Moreover, the expression of genes encoding vasopressin (AVP), vasoactive intestinal peptide (VIP) in the SCN, and AVP and oxytocin (OXT) in the PVN were studied by in situ hybridization. Expression of the per1 gene showed a distinct circadian rhythm in both the SCN and PVN with no differences observed between the TGR and control Sprague–Dawley (SD) rats. The expression of avp in the SCN was rhythmic in both strains and moderately higher in TGR than in SD rats while no significant changes were found in the PVN. The expression of vip in the SCN and oxt in the PVN did not differ between both strains. Our results may indicate that changes occurring downstream to the SCN are responsible for the development of the inverted BP rhythm in TGR hypertensive rats. KeywordsHypertension–Circadian rhythm–Suprachiasmatic nucleus–Paraventricular nucleus–Vasopressin–Oxytocin
  Cellular and Molecular Neurobiology 04/2012; 31(2):225-232.
• Article: Progressive reparative gliosis in aged hosts and interferences with neural grafts in an animal model of Huntington's disease.

  Yvona Mazurová, Ivan Látr, Jan Osterreicher, Ivana Guncová
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  ABSTRACT: 1. Neural transplantation in Huntington's diseased patients is currently the only approach in the treatment of this neurodegenerative disorder. The clinical trial, unfortunately, includes only a small number of patients until now, since many important questions have not been answered yet. One of them is only mild to moderate improvement of the state in most of grafted patients. 2. We examined the morphological correlates in the response to intrastriatal grafting of fragments of foetal rat ventral mesencephalic tissue 1 month after transplantation in male Wistar rats within varying durations (from 2 to 38 weeks) of experimentally induced neurodegenerative process of the striatum (used as a model of Huntington's disease). Our goal was to determine the impact of advanced striatal damage and gliosis on the graft viability and host-graft integration. 3. The findings can be summarized as follows: The progressive reactive gliosis, which is not able to compensate continual reduction of the grey matter leading to an extensive atrophy of the striatum in a long-term lesions, results in formation of the compact glial network. This tissue cannot be considered the suitable terrain for successful graft development and formation of host-graft interconnections. 4. The progression of irreversible morphological changes in long-lasting neurodegenerative process within the striatum can be supposed one of the important factors, which may decrease our prospect of distinct improvement after neural grafting in patients in advanced stage of Huntington's disease, who still remain the leading group in clinical trials.
  Cellular and Molecular Neurobiology 04/2012; 26(7-8):1423-41.
• Article: Stimulation of the Rat’s Sciatic Nerve Regeneration by Local Treatment with Xymedon®

  Ruslan Masgutov, Ivan Raginov, Galina Fomina, Maria Kozlova, Yuri Chelyshev
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  ABSTRACT: 1. The possibility of a neuro-protective effect of Xymedon as a pharmacological stimulator of nerve regeneration has been studied through Schwann cells (SCs) located in the potential area of regenerating nerve fibers’ growth.2. Xymedon was injected into the silicone chamber connecting the central and peripheral stumps of the rat’s sciatic nerve. Carboxymethyl cellulose was used as a depositioned medium.3. A 0.95% concentration of Xymedon increased the sciatic nerve functional index (SFI) values on the 14th, 21st and 28th day after the operation. By day 30, the total number of survival neurons in the L5 dorsal root ganglion (DRG) on the ipsilateral side increased with the following changes in Xymedon concentration: $ \displaylines{ ({\rm depositioned} \,{\rm medium} + 9.5\% \,{\rm Xymedon}) \to({\rm depositioned}\,{\rm medium} + 4.75\% \,{\rm Xymedon})\cr \to ({\rm without}\,{\rm depositioned}\,{\rm medium}\,{\rm and}\,{\rm Xymedon})\cr \to ({\rm depositioned}\,{\rm medium} + 0.95\% \,{\rm Xymedon}).} $ \displaylines{ ({\rm depositioned} \,{\rm medium} + 9.5\% \,{\rm Xymedon}) \to({\rm depositioned}\,{\rm medium} + 4.75\% \,{\rm Xymedon})\cr \to ({\rm without}\,{\rm depositioned}\,{\rm medium}\,{\rm and}\,{\rm Xymedon})\cr \to ({\rm depositioned}\,{\rm medium} + 0.95\% \,{\rm Xymedon}).} The number of surviving sensory neurons in the group with 0.95% Xymedon increased by 36% (p < 0.05) compared with animals with depositioned medium but Xymedon free.4. It is suggested that the positive effects of Xymedon on neural regeneration and recovery of motor function support the potential use of Xymedon for the treatment of peripheral nerve injuries.
  Cellular and Molecular Neurobiology 04/2012; 26(7):1411-1419.
• Article: Effects of Long-Term FK506 Administration on Functional and Histopathological Outcome after Spinal Cord Injury in Adult Rat

  Kamila Saganová, Judita Orendáčová, Igor Šulla, Peter Filipčík, Dáša Čížková, Ivo Vanický
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  ABSTRACT: FK506 (tacrolimus), a potent immunosuppressive drug primarily used for reduction of allograft rejection in organ transplantation, also offers neuroprotection after central nervous system injury. FK506-mediated immunosuppression and neuroprotection may occur through different mechanisms that could affect neurological recovery and the severity of spinal lesions where cells transplantation therapy is combined with FK506 application. We assessed effects of long-term FK506 administration using the same dose regiment (1mg/kg/day for 6weeks) as is used in spinal cord transplantation studies following a balloon-compression induced spinal cord injury (SCI). Body weight and locomotor recovery quantified by the BBB (Basso-Beattie-Bresnehan) locomotor rating scale were evaluated for up to 42days post-injury. The area of the preserved spinal cord tissue within a 13mm segment of the spinal cord (lesion epicenter and 6mm rostral-caudal) was examined histologically. The results showed no significant effects of FK506 on spinal cord tissue sparing or improvement of locomotor recovery. However, body weight fell significantly (P<0.05) with FK506 treatment when compared with placebo from day 7 until sacrifice. In our experimental design, long-term FK506 treatment did not affect the parameters of outcome following balloon-compression SCI in the rat; however, multiple effects of FK506 should be taken into account when evaluating the outcomes in transplantation studies.
  Cellular and Molecular Neurobiology 04/2012; 29(6):1045-1051.
• Article: Alpha-Tocopherol Decreases Iron-Induced Hippocampal and Nigral Neuron Loss

  M. Ömer Bostanci, Orhan Bas, Faruk Bagirici
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  ABSTRACT: There are many studies about iron-induced neuronal hyperactivity and oxidative stress. Some reports also showed that iron levels rise in the brain in some neurodegenerative diseases such as Parkinson’s (PD) and Alzheimer’s disease (AD). It has been suggested that excessive iron level increases oxidative stress and causes neuronal death. Tocopherols act as a free radical scavenger when phenoxylic head group encounters a free radical. We have aimed to identify the effect of α-tocopherol (Vitamin E) on iron-induced neurotoxicity. For this reason, rats were divided into three groups as control, iron, and iron+α-tocopherol groups. Iron chloride (200mM in 2.5μl volume) was injected into brain ventricle of iron and iron+α-tocopherol group rats. Same volume of saline (2.5μl) was given to the rats belonging to control group. Rats of iron+α-tocopherol group received intraperitoneally (i.p.) α-tocopherol (100mg/kg/day) for 10days. After 10days, rats were perfused intracardially under deep urethane anesthesia. Removed brains were processed using standard histological techniques. The numbers of neurons in hippocampus and substantia nigra of all rats were estimated by stereological techniques. Results of present study show that α-tocopherol decreased hippocampal and nigral neuron loss from 51.7 to 12.1% and 41.6 to 17.8%, respectively. Findings of the present study suggest that α-tocopherol may have neuroprotective effects against iron-induced hippocampal and nigral neurotoxicity and it may have a therapeutic significance for neurodegenerative diseases involved iron. KeywordsIron-Hippocampus-Substantia nigra-Cell death-Alpha-tocopherol-Stereology
  Cellular and Molecular Neurobiology 04/2012; 30(3):389-394.
• Article: Is Vitamin E Toxic to Neuron Cells?

  Sue Mian Then, Musalmah Mazlan, Gapor Mat Top, Wan Zurinah Wan Ngah
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  ABSTRACT: Besides acting as potent free radical scavengers, tocopherols and tocotrienols have been known to have non-antioxidant properties such as the involvement of α-tocopherol (αT) in PKC pathway and the anti-cancer properties of γ-tocotrienol (γT3). This study aims to elucidate whether protective effects shown by αT and γT3 in H2O2-induced neuron cultures have anti-apoptotic or pro-apoptotic tendency toward the initiation of neuronal apoptosis. H2O2 is used to induce apoptosis in primary cerebellar neuron cultures which is attenuated by pretreatment of αT or γT3 at concentrations ≤10μM. Similar to our previous work, γT3 was found to be neurotoxic at concentrations ≥100μM, whereas αT showed no neurotoxicity. Cellular uptake of γT3 was higher than that of αT. Treating cells simultaneously with either γT3 or αT and with then H2O2 led to higher expression of Bax and Bcl-2 than in neurons exposed to H2O2 alone. Analysis of Bcl-2/Bax ratio as ‘survival index’ showed that both pretreatment of γT3 and αT followed by H2O2 increase the ‘survival index’ of Bcl-2/Bax ratio compared to H2O2-treated cells, while treatment of γT3 alone decrease the ratio compared to unchanged Bcl2/Bax ratio of similar treatment with αT alone. Similar treatment of γT3 decreased p53 expression and activates p38 MAPK phosphorylation, whereas αT did not alter its expression compared to H2O2-treated cells. Treating neurons with only γT3 or αT increased the expression of Bax, Bcl-2, p53, and p38 MAPK compared to control with γT3 exerting stronger expression for proteins involved than αT. In conclusion, low doses of γT3 and αT confer neuroprotection to H2O2-treated neurons via their antioxidant mechanism but γT3 has stronger pro-apoptosis tendency than αT by activating molecules involved in the neuronal apoptotic pathway in the absence of H2O2.
  Cellular and Molecular Neurobiology 04/2012; 29(4):485-496.
• Article: Long-Term Changes in Spinal Cord Evoked Potentials After Compression Spinal Cord Injury in the Rat

  Ivo Vanický, Tomáš Ondrejčák, Miriam Ondrejčáková, Igor Šulla, Ján Gálik
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  ABSTRACT: 1. After traumatic spinal cord injury (SCI), histological and neurological consequences are developing for several days and even weeks. However, little is known about the dynamics of changes in spinal axonal conductivity. The aim of this study was to record and compare repeated spinal cord evoked potentials (SCEP) after SCI in the rat during a 4 weeks’ interval. These recordings were used: (i) for studying the dynamics of functional changes in spinal axons after SCI, and (ii) to define the value of SCEP as an independent outcome parameter in SCI studies.2. We have used two pairs of chronically implanted epidural electrodes for stimulation/recording. The electrodes were placed below and above the site of injury, respectively. Animals with implanted electrodes underwent spinal cord compression injury induced by epidural balloon inflation at Th8–Th9 level. There were five experimental groups of animals, including one control group (sham-operated, no injury), and four injury groups (different degrees of SCI).3. After SCI, SCEP waveform was either significantly reduced or completely lost. Partial recovery of SCEPs was observed in all groups. The onset and extent of recovery clearly correlated with the severity of injury.There was good correlation between quantitated SCEP variables and the volumes of the compressing balloon. However, sensitivity of electropohysiological parameters was inferior compared to neurological and morphometric outcomes.4. Our study shows for the first time, that the dynamics of axonal recovery depends on the degree of injury. After mild injury, recovery of signal is rapid. However, after severe injury, axonal conductivity can re-appear after as long as 2 weeks postinjury.In conclusion, SCEPs can be used as an independent parameter of outcome after SCI, but in general, the sensitivity of electrophysiological data were worse than standard morphological and neurological evaluations.
  Cellular and Molecular Neurobiology 04/2012; 26(7):1519-1537.
• Article: Akt as a Victim, Villain and Potential Hero in Parkinson’s Disease Pathophysiology and Treatment

  Lloyd A. Greene, Oren Levy, Cristina Malagelada
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  ABSTRACT: There are two major purposes of this essay. The first is to summarize existing evidence that irrespective of the initiating causes, neuron death and degeneration in Parkinson’s disease (PD) are due to the common feature of failure of signaling by Akt, a kinase involved in neuron survival and maintenance of synaptic contacts. The second is to consider possible means by which such a failure of Akt signaling might be benignly prevented or reversed in neurons affected by PD, so as to treat PD symptoms, block disease progression, and potentially, promote recovery. KeywordsParkinson’s disease–Akt–Neurodegeneration–Neuroprotection
  Cellular and Molecular Neurobiology 04/2012; 31(7):969-978.
• Article: John William Daly, 1933–2008

  H. Martin Garraffo
  Cellular and Molecular Neurobiology 04/2012; 29(4):439-440.
• Article: A Novel Mitochondrial Heteroplasmic C13806A Point Mutation Associated with Iranian Friedreich’s Ataxia

  Mohammad Mehdi Heidari, Massoud Houshmand, Saman Hosseinkhani, Shahriar Nafissi, Barbara Scheiber-Mojdehkar, Mehri Khatami
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  ABSTRACT: Friedreich’s ataxia (FRDA) is an autosomal recessive neurodegenerative disorder caused by decreased expression of the protein Frataxin. Frataxin deficiency leads to excessive free radical production and dysfunction of chain complexes. Mitochondrial DNA (mtDNA) could be considered a candidate modifier factor for FRDA disease, since mitochondrial oxidative stress is thought to be involved in the pathogenesis of this disease. It prompted us to focus on the mtDNA and monitor the nucleotide changes of genome which are probably the cause of respiratory chain defects and reduced ATP generation. We searched about 46% of the entire mitochondrial genome by temporal temperature gradient gel electrophoresis (TTGE) and DNA fragments showing abnormal banding patterns were sequenced for the identification of exact mutations. In 18 patients, for the first time, we detected 26 mtDNA mutations; of which 5 (19.2%) was novel and 21 (80.8%) have been reported in other diseases. Heteroplasmic C13806A polymorphisms were associated with Iranian FRDA patients (55.5%). Our results showed that NADH dehydrogenase (ND) genes mutations in FRDA samples were higher than normal controls (P<0.001) and we found statistically significant inverse correlation (r=−0.8) between number of mutation in ND genes and age of onset in FRDA patients. It is possible that mutations in ND genes could constitute a predisposing factor which in combination with environmental risk factors affects age of onset and disease progression.
  Cellular and Molecular Neurobiology 04/2012; 29(2):225-233.
• Article: Do Haplogroups H and U Act to Increase the Penetrance of Alzheimer’s Disease?

  Farzaneh Fesahat, Massoud Houshmand, Mehdi Shafa Shariat Panahi, Kurosh Gharagozli, Farzaneh Mirzajani
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  ABSTRACT: 1. Alzheimer’s disease (AD) is the most common form of dementia in the elderly in which interplay between genes and the environment is supposed to be involved. Mitochondrial DNA (mtDNA) has the only noncoding regions at the displacement loop (D-loop) region that contains two hypervariable segments (HVS-I and HVS-II) with high polymorphism. mtDNA has already been fully sequenced and many subsequent publications have shown polymorphic sites, haplogroups, and haplotypes. Haplogroups could have important implications to understand the association between mutability of the mitochondrial genome and the disease. 2. To assess the relationship between mtDNA haplogroup and AD, we sequenced the mtDNA HVS-I in 30 AD patients and 100 control subjects. We could find that haplogroups H and U are significantly more abundant in AD patients (P=0.016 for haplogroup H and P=0.0003 for haplogroup U), Thus, these two haplogroups might act synergistically to increase the penetrance of AD disease.
  Cellular and Molecular Neurobiology 04/2012; 27(3):329-334.
• Article: Aβ Oligomer-Induced Synapse Degeneration in Alzheimer’s Disease

  Kyle C. Wilcox, Pascale N. Lacor, Jason Pitt, William L. Klein
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  ABSTRACT: Aβ oligomers cause a collection of molecular events associated with memory loss in Alzheimer’s disease, centering on disrupting the maintenance of synapse structure and function. In this brief review of the synaptotoxic effects of Aβ oligomers, we focus on the neuronal properties governing oligomer targeting and toxicity—especially with respect to binding sites and mechanisms of binding. We also discuss ways in which mechanistic insights from other diseases offer clues in the pursuit of the molecular basis of Alzheimer’s disease. KeywordsAlzheimer’s disease–Synapse degeneration–Aβ oligomers–mGluR5–Fragile X syndrome–Insulin dysfunction
  Cellular and Molecular Neurobiology 04/2012; 31(6):939-948.
• Article: Thyroid Hormone Mediates Syndecan Expression in Rat Neonatal Cerebellum

  Cláudia Beatriz Nedel Mendes-de-Aguiar, Bruno Costa-Silva, Marcio Alvarez-Silva, Carla Inês Tasca, Andréa Gonçalves Trentin
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  ABSTRACT: Thyroid hormone (T3) plays an essential role in the central nervous system development. Astrocytes mediate many of the T3 effects in the growth and differentiation of cerebellum. In culture, T3 induces cerebellar astrocytes to secrete growth factors, mainly FGF2, and alters the expression and organization of the extracellular matrix (ECM) proteins, laminin, and fibronectin. In addition, T3-treated astrocytes promote neuronal differentiation. In this study, we have investigated whether other ECM molecules, such as syndecans, are involved in T3 action. Thus, we analyzed the expression of syndecans (1–4) by RT-PCR in astrocyte cultures from cerebellum, cortex, and hippocampus of newborn rats. Our results showed that syndecans (1–4) are expressed in astrocytes of cerebellum and cortex, whereas in hippocampus only syndecans 2 and 4 were detected. Semi-quantitative RT-PCR analysis revealed the reduced expression of syndecans 1, 2, and 4, and increased expression of syndecan 3 in hypothyroid cerebellum, when compared to the euthyroid tissue. Furthermore, we observed a reduced expression of syndecans 2 and 3 in T3-treated cerebellar astrocytes, when compared to control cultures. This balance of proteoglycans may be involved in T3 action mediated by FGF2 signaling, possibly affecting the formation of the trimeric signaling receptor complex composed by syndecan/FGF/FGF-receptor (FGFR), which is essential for FGFR dimerization, activation, and subsequent cell signaling.
  Cellular and Molecular Neurobiology 04/2012; 28(6):795-801.
• Article: Resveratrol Increases Glutamate Uptake, Glutathione Content, and S100B Secretion in Cortical Astrocyte Cultures

  Lúcia Maria Vieira de Almeida, Cristopher Celintano Piñeiro, Marina Concli Leite, Giovana Brolese, Francine Tramontina, Ana Maria Feoli, Carmem Gottfried, Carlos-Alberto Gonçalves
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  ABSTRACT: Resveratrol (3,5,4′-trihydroxy-trans-stilbene) is a polyphenol present in grapes and red wine, which has antioxidant properties and a wide range of other biological effects. In this study, we investigated the effect of resveratrol, in a concentration range of 10–250μM, on primary cortical astrocytes; evaluating cell morphology, parameters of glutamate metabolism such as glutamate uptake, glutamine synthetase activity and glutathione total content, and S100B secretion. Astrocyte cultures were prepared of cerebral cortex from neonate Wistar rats. Morphology was evaluated by phase-contrast microscopy and immunocytochemistry for glial fibrillary acidic protein (GFAP). Glutamate uptake was measured using l-[2,3-3H]glutamate. Glutamine synthetase and content of glutathione were measured by enzymatic colorimetric assays. S100B content was determined by ELISA. Typical polygonal morphology becomes stellated when astrocyte cultures were exposed to 250μM resveratrol for 24h. At concentration of 25μM, resveratrol was able to increase glutamate uptake and glutathione content. Conversely, at 250μM, resveratrol decreased glutamate uptake. Unexpectedly, resveratrol at this high concentration increased glutamine synthetase activity. Extracellular S100B increased from 50μM upwards. Our findings reinforce the protective role of this compound in some brain disorders, particularly those involving glutamate toxicity. However, the underlying mechanisms of these changes are not clear at the moment and it is necessary caution with its administration because elevated levels of this compound could contribute to aggravate these conditions.
  Cellular and Molecular Neurobiology 04/2012; 27(5):661-668.
• Article: Naturally Occurring Genetic Variants in Human Chromogranin A (CHGA) Associated with Hypertension as well as Hypertensive Renal Disease

  Yuqing Chen, Fangwen Rao, Gen Wen, Jiaur R. Gayen, Kuixing Zhang, Sucheta M. Vaingankar, Nilima Biswas, Manjula Mahata, Ryan S. Friese, Maple M. Fung, Rany M. Salem, Caroline Nievergelt, Vibha Bhatnagar, Vivian Y. Hook, Michael G. Ziegler, Sushil K. Mahata, Bruce A. Hamilton, Daniel T. O’Connor
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  ABSTRACT: Chromogranin A (CHGA) plays a fundamental role in the biogenesis of catecholamine secretory granules. Changes in storage and release of CHGA in clinical and experimental hypertension prompted us to study whether genetic variation at the CHGA locus might contribute to alterations in autonomic function, and hence hypertension and its target organ consequences such as hypertensive renal disease (nephrosclerosis). Systematic polymorphism discovery across the human CHGA locus revealed both common and unusual variants in both the open reading frame and such regulatory regions as the proximal promoter and 3′-UTR. In chromaffin cell-transfected CHGA 3′-UTR and promoter/luciferase reporter plasmids, the functional consequences of the regulatory/non-coding allelic variants were documented. Variants in both the proximal promoter and the 3′-UTR displayed statistical associations with hypertension. Genetic variation in the proximal CHGA promoter predicted glomerular filtration rate in healthy twins. However, for hypertensive renal damage, both end-stage renal disease and rate of progression of earlier disease were best predicted by variants in the 3′-UTR. Finally, mechanistic studies were undertaken initiated by the clue that CHGA promoter variation predicted circulating endothelin-1. In cultured endothelial cells, CHGA triggered co-release of not only the vasoconstrictor and pro-fibrotic endothelin-1, but also the pro-coagulant von Willebrand Factor and the pro-angiogenic angiopoietin-2. These findings, coupled with stimulation of endothelin-1 release from glomerular capillary endothelial cells by CHGA, suggest a plausible mechanism whereby genetic variation at the CHGA locus eventuates in alterations in human renal function. These results document the consequences of genetic variation at the CHGA locus for cardiorenal disease and suggest mechanisms whereby such variation achieves functional effects. KeywordsCHGA-Hypertension-Hypertensive nephrosclerosis
  Cellular and Molecular Neurobiology 04/2012; 30(8):1395-1400.