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Benarroch E. What Are the Functions of Zinc in the Nervous System? Neurology 2023; 101:714-720. [PMID: 37845046 PMCID: PMC10585682 DOI: 10.1212/wnl.0000000000207912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 08/16/2023] [Indexed: 10/18/2023] Open
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Tyulmenkova A, Zwick A, Dillon T, Isgor C. Progressive generalized tonic-clonic seizures in a transgenic mouse model of adult-onset epilepsy: Implications for morphological changes in cortico-limbic and brainstem structures. Epilepsy Res 2023; 194:107178. [PMID: 37295319 PMCID: PMC10527249 DOI: 10.1016/j.eplepsyres.2023.107178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 05/21/2023] [Accepted: 06/01/2023] [Indexed: 06/12/2023]
Abstract
Video/cortical electroencephalography (EEG) is monitored to assess progressive severity of generalized tonic clonic seizures (GTCSs) in a transgenic mouse model of adult-onset epilepsy with increased death risk. The mice overexpress the brain derived neurotrophic factor (BDNF) in the forebrain under the calcium/calmodulin dependent protein kinase 2a (termed TgBDNF) and develop GTCSs in response to tail suspension/cage agitation stimulation at 3-4 months of age. With successive GTCSs (a total of 16 across 10 weeks of assessment), seizures became more severe as evidenced by increased duration of postictal generalized EEG suppression (PGES) associated with loss of posture/consciousness. Mice also developed spike wave discharges with behavioral arrest during the seizure recovery that increased in duration as a function of number of GTCSs. Overall seizure duration (from preictal spike to offset of PGES) and ictal spectral power (full spectra) were also increased. Half of the TgBDNF mice expired following a long period of PGES at the last recorded GTCS. Seizure-evoked general arousal impairment was associated with a striking decrease in total number of gigantocellular neurons of the brainstem nucleus pontis oralis along with increase in volumes of the anterior cingulate cortex and dorsal dentate gyrus in severely convulsive TgBDNF mice compared to litter-matched WT controls and non-convulsive TgBDNF mice. The latter effect was accompanied with an increase in total number of hippocampal granule neurons. These results provide structure-function associations in an animal model of adult-onset GTCSs that progressively increase in severity with clinical relevance for sudden unexpected death following generalized seizures.
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Affiliation(s)
- Anastasia Tyulmenkova
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - Amanda Zwick
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - Tashi Dillon
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - Ceylan Isgor
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA.
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3
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Zhang Y, Gao X, Bai X, Yao S, Chang YZ, Gao G. The emerging role of furin in neurodegenerative and neuropsychiatric diseases. Transl Neurodegener 2022; 11:39. [PMID: 35996194 PMCID: PMC9395820 DOI: 10.1186/s40035-022-00313-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 08/10/2022] [Indexed: 12/02/2022] Open
Abstract
Furin is an important mammalian proprotein convertase that catalyzes the proteolytic maturation of a variety of prohormones and proproteins in the secretory pathway. In the brain, the substrates of furin include the proproteins of growth factors, receptors and enzymes. Emerging evidence, such as reduced FURIN mRNA expression in the brains of Alzheimer's disease patients or schizophrenia patients, has implicated a crucial role of furin in the pathophysiology of neurodegenerative and neuropsychiatric diseases. Currently, compared to cancer and infectious diseases, the aberrant expression of furin and its pharmaceutical potentials in neurological diseases remain poorly understood. In this article, we provide an overview on the physiological roles of furin and its substrates in the brain, summarize the deregulation of furin expression and its effects in neurodegenerative and neuropsychiatric disorders, and discuss the implications and current approaches that target furin for therapeutic interventions. This review may expedite future studies to clarify the molecular mechanisms of furin deregulation and involvement in the pathogenesis of neurodegenerative and neuropsychiatric diseases, and to develop new diagnosis and treatment strategies for these diseases.
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Affiliation(s)
- Yi Zhang
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Laboratory of Molecular Iron Metabolism, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
| | - Xiaoqin Gao
- Shijiazhuang People's Hospital, Hebei Medical University, Shijiazhuang, 050027, China
| | - Xue Bai
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Laboratory of Molecular Iron Metabolism, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
| | - Shanshan Yao
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Laboratory of Molecular Iron Metabolism, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
| | - Yan-Zhong Chang
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Laboratory of Molecular Iron Metabolism, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China.
| | - Guofen Gao
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Laboratory of Molecular Iron Metabolism, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China.
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4
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Yang Y, Li Y, Han J, Wang Y. Gastrodin attenuates lithium-pilocarpine-induced epilepsy by activating AMPK-mediated PPARα in a juvenile rat model. Biosci Biotechnol Biochem 2021; 85:798-804. [PMID: 33704382 DOI: 10.1093/bbb/zbab013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 11/21/2020] [Indexed: 12/24/2022]
Abstract
Gastrodin has shown the potential as an anticonvulsant. Epilepsy is a neurological disease with significant effects in children. In the current study, the therapeutic potential of gastrodin in handling pediatric epilepsy was explored by focusing on the AMPK/PPARα pathway. Three-week-old Sprague-Dawley rats were subjected to lithium-pilocarpine method to induce epileptic symptoms and then administrated with gastrodin. The effects of gastrodin on rats were first assessed using electroencephalogram (EEG) recording, Racine classification, Morris water maze test, and histological staining. The levels of BDNF and NGF, and the activity of AMPK/PPARα were measured. Based on the results of EEG, behavior analyses, and histological staining, epileptic symptoms were significantly alleviated by gastrodin. Moreover, the administration of gastrodin also suppressed the levels of BDNF and NGF, and activated the AMPK/PPARα pathway. In conclusion, our results demonstrated that gastrodin contributed to the alleviation of pediatric epilepsy by activating AMPK/PPARα signaling transduction.
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Affiliation(s)
- Yanfei Yang
- Department of Pediatrics, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Taiyuan, Shanxi, China
| | - Yabin Li
- Department of Pediatrics, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Taiyuan, Shanxi, China
| | - Jinli Han
- Department of Pediatrics, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Taiyuan, Shanxi, China
| | - Yanfen Wang
- Department of Pediatrics, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Taiyuan, Shanxi, China
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Freiman TM, Häussler U, Zentner J, Doostkam S, Beck J, Scheiwe C, Brandt A, Haas CA, Puhahn-Schmeiser B. Mossy fiber sprouting into the hippocampal region CA2 in patients with temporal lobe epilepsy. Hippocampus 2021; 31:580-592. [PMID: 33720466 DOI: 10.1002/hipo.23323] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 02/23/2021] [Accepted: 02/27/2021] [Indexed: 01/28/2023]
Abstract
Hippocampal sclerosis (HS) in Temporal Lobe Epilepsy (TLE) shows neuronal death in cornu ammonis (CA)1, CA3, and CA4. It is known that granule cells and CA2 neurons survive and their axons, the mossy fibers (MF), lose their target cells in CA3 and CA4 and sprout to the granule cell layer and molecular layer. We examined in TLE patients and in a mouse epilepsy model, whether MF sprouting is directed to the dentate gyrus or extends to distant CA regions and whether sprouting is associated with death of target neurons in CA3 and CA4. In 319 TLE patients, HS was evaluated by Wyler grade and International League against Epilepsy (ILAE) types using immunohistochemistry against neuronal nuclei (NeuN). Synaptoporin was used to colocalize MF. In addition, transgenic Thy1-eGFP mice were intrahippocampally injected with kainate and sprouting of eGFP-positive MFs was analyzed together with immunocytochemistry for regulator of G-protein signaling 14 (RGS14). In human HS Wyler III and IV as well as in ILAE 1, 2, and 3 specimens, we found synaptoporin-positive axon terminals in CA2 and even in CA1, associated with the extent of granule cell dispersion. Sprouting was seen in cases with cell death of target neurons in CA3 and CA4 (classical severe HS ILAE type 1) but also without this cell death (atypical HS ILAE type 2). Similarly, in epileptic mice eGFP-positive MFs sprouted to CA2 and beyond. The presence of MF terminals in the CA2 pyramidal cell layer and in CA1 was also correlated with the extent of granule cell dispersion. The similarity of our findings in human specimens and in the mouse model highlights the importance and opens up new chances of using translational approaches to determine mechanisms underlying TLE.
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Affiliation(s)
- Thomas M Freiman
- Department of Neurosurgery, Rostock University Medical Center, Rostock, Germany
| | - Ute Häussler
- Department of Neurosurgery, Experimental Epilepsy Research, Medical Center-University of Freiburg, Faculty of Medicine, Freiburg, Germany.,Faculty of Medicine, Center for Basics in NeuroModulation, University of Freiburg, Freiburg, Germany.,BrainLinks-BrainTools Center, University of Freiburg, Freiburg, Germany
| | - Josef Zentner
- Faculty of Medicine, Department of Neurosurgery, Medical Center-University of Freiburg, Freiburg, Germany
| | - Soroush Doostkam
- Faculty of Medicine, Institute of Neuropathology, Medical Center-University of Freiburg, Freiburg, Germany
| | - Jürgen Beck
- Faculty of Medicine, Department of Neurosurgery, Medical Center-University of Freiburg, Freiburg, Germany
| | - Christian Scheiwe
- Faculty of Medicine, Department of Neurosurgery, Medical Center-University of Freiburg, Freiburg, Germany
| | - Armin Brandt
- Epilepsy Center, University Medical Center, Albert-Ludwigs-University, Freiburg, Germany
| | - Carola A Haas
- Department of Neurosurgery, Experimental Epilepsy Research, Medical Center-University of Freiburg, Faculty of Medicine, Freiburg, Germany.,Faculty of Medicine, Center for Basics in NeuroModulation, University of Freiburg, Freiburg, Germany.,BrainLinks-BrainTools Center, University of Freiburg, Freiburg, Germany
| | - Barbara Puhahn-Schmeiser
- Faculty of Medicine, Department of Neurosurgery, Medical Center-University of Freiburg, Freiburg, Germany
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CSF levels of a set of neurotrophic factors (brain-derived neurotrophic factor, nerve growth factor) and neuropeptides (neuropeptide Y, galanin) in epileptic children. J Clin Neurosci 2020; 76:41-45. [PMID: 32327377 DOI: 10.1016/j.jocn.2020.04.064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 04/12/2020] [Indexed: 01/03/2023]
Abstract
This paper aims to investigate the possible roles of a set of neurotrophic factors (brain-derived neurotrophic factor-BDNF, nerve growth factor-NGF) and neuropeptides (neuropeptide Y-NPY, and galanin) in children with active epileptogenesis. The cerebrospinal fluid (CSF) levels of BDNF, NPY, NGF and galanin were measured with enzyme-linked immunosorbent assays in epileptic children (n = 73) and controls (n = 64). There were no significant alterations in the CSF levels of BDNF, NPY and NGF in epileptic children with active clinical seizures compared with the levels of controls. However profoundly depressed galanin levels were found in infants with epileptic encephalopathy (mean ± SD:0.63 ± 0.19 pg/ml) and significantly increased galanin levels were measured in children with drug resistant epilepsy during the period of status epilepticus (mean ± SD: 6.92 ± 1.19, pg/ml pg/ml) compared with the levels of controls. Depressed levels of galanin might reflect a defective anti-epileptogenic effect of galanin in infants with epileptic encephalopathy. On the contrary, increased CSF levels of galanin might be a result of anti-epileptogenic effects of this peptide in epileptic children with status epilepticus.
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Göl MF, Erdoğan FF, Bayramov KK, Mehmetbeyoğlu E, Özkul Y. Assessment of genes involved in behavior, learning, memory, and synaptic plasticity following status epilepticus in rats. Epilepsy Behav 2019; 98:101-109. [PMID: 31326869 DOI: 10.1016/j.yebeh.2019.06.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 06/09/2019] [Accepted: 06/11/2019] [Indexed: 02/05/2023]
Abstract
OBJECTIVE In this study, it was aimed to evaluate cognitive and behavioral changes after status epilepticus (SE) induced by pentylenetetrazole in immature rats via Morris water maze and open-field area tests and to assess alterations in expression of 84 key genes involved in synaptic plasticity after SE. METHOD The study was conducted on 30 immature rats (12-days old). The rats were assigned into groups as control and experiment (SE) groups. The SE was induced by pentylenetetrazole in 12-days old rats. In addition, experiment group was divided into two groups as mature (n = 8) and immature SE (n = 8) subgroups. Again, the control group was divided into two groups as mature (n = 7) and immature control (n = 7) subgroups. Hippocampal tissue samples were prepared, and expression of 84 key genes involved in synaptic plasticity was assessed in Genome and Stem Cell Center of Erciyes University before behavioral tests in immature rats (22-days old) and after open-filed area and Morris water maze tests in mature rats (72-days old) in both experiment and control groups. RESULTS No significant difference was detected in behavioral tests assessing spatial memory and learning among groups. Significant differences were detected, ARC (activity-regulated cytoskeleton-associated protein), BDNF (brain-derived neurotrophic factor), MAPK1 (mitogen-activated protein kinase 1), NR4A1 (nuclear receptor subfamily 4 group A member 1), PPP3CA (protein phosphatase 3 catalytic subunit alpha), RGS2 (regulator of G protein signaling 2), and TNF (tumor necrosis factor) gene expressions between control and experiment groups in immature rats whereas in ADCY8 (adenylate cyclase 8), BDNF (brain-derived neurotrophic factor), EGR4 (early growth response 4), and KIF17 (kinesin family member 17) gene expressions between control and experiment groups in mature rats. DISCUSSION In this study, differences detected in gene expressions of synaptic plasticity after SE indicate in which steps of synaptic plasticity may be problematic in epileptogenesis. The gene expressions in this study may be considered as potential biomarkers; however, epileptogenesis is a dynamic process and cannot be explained through a single mechanism. Future studies on epileptogenesis and studies specifically designed to evaluate genes detected in our study will further elucidate synaptic plasticity in epilepsy and epileptogenesis.
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Affiliation(s)
- Mehmet Fatih Göl
- Department of Neurology, Kayseri City Hospital, Kayseri, Turkey.
| | - Füsun Ferda Erdoğan
- Department of Neurology, Erciyes University Faculty of Medicine, Kayseri, Turkey
| | | | | | - Yusuf Özkul
- Department of Medical Genetics, Erciyes University Faculty of Medicine, Kayseri, Turkey
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Tulke S, Haas CA, Häussler U. Expression of brain‐derived neurotrophic factor and structural plasticity in the dentate gyrus and
CA
2 region correlate with epileptiform activity. Epilepsia 2019; 60:1234-1247. [DOI: 10.1111/epi.15540] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 04/17/2019] [Accepted: 04/22/2019] [Indexed: 01/29/2023]
Affiliation(s)
- Susanne Tulke
- Experimental Epilepsy Research Department of Neurosurgery Medical Center - University of Freiburg Faculty of Medicine University of Freiburg Freiburg im Breisgau Germany
- Faculty of Biology University of Freiburg Freiburg im Breisgau Germany
| | - Carola A. Haas
- Experimental Epilepsy Research Department of Neurosurgery Medical Center - University of Freiburg Faculty of Medicine University of Freiburg Freiburg im Breisgau Germany
- BrainLinks‐BrainTools Cluster of Excellence University of Freiburg Freiburg im Breisgau Germany
| | - Ute Häussler
- Experimental Epilepsy Research Department of Neurosurgery Medical Center - University of Freiburg Faculty of Medicine University of Freiburg Freiburg im Breisgau Germany
- BrainLinks‐BrainTools Cluster of Excellence University of Freiburg Freiburg im Breisgau Germany
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Tchekalarova J, Atanasova D, Kortenska L, Lazarov N, Shishmanova-Doseva M, Galchev T, Marinov P. Agomelatine alleviates neuronal loss through BDNF signaling in the post-status epilepticus model induced by kainic acid in rat. Brain Res Bull 2019; 147:22-35. [PMID: 30738136 DOI: 10.1016/j.brainresbull.2019.01.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 01/12/2019] [Accepted: 01/16/2019] [Indexed: 12/11/2022]
Abstract
Recently, we have reported that while agomelatine (Ago) is unable to prevent development of epilepsy it exerts a strong neuroprotective and anti-inflammatory response in the KA post-status epilepticus (SE) rat model. In the present study, we aimed to explore whether the brain-derived neurotrophic factor (BDNF) in the hippocampus is involved in the neuroprotective effect of Ago against the KA-induced SE and epileptiform activity four months later in rats. Lacosamide (LCM) was used as a positive control. The EEG-recorded seizure activity was also evaluated in two treatment protocols. In Experiment#1, Ago given repeatedly at a dose of 40 mg/kg during the course of SE was unable neither to modify EEG-recorded epileptiform activity nor the video- and EEG-recorded spontaneous seizures four months later compared to LCM (50 mg/kg). However, both Ago and LCM inhibited the expression of BDNF in the mossy fibers and also prevented neuronal loss in the dorsal hippocampal and the piriform cortex after SE. In Experiment#2, acute injection of Ago and LCM on epileptic rats, characterized by high seizure rates, did not prevent EEG-recorded paroxysmal events while only LCM decreased either absolute or relative powers of gamma (28-60 Hz) and high (HI) (60-120 Hz) frequency bands to baseline in the frontal and parietal cortex, respectively. Our results suggest that the protection against neuronal loss in specific limbic regions and overexpressed BDNF in the mossy fibers resulting from the repeated treatment with Ago and LCM, respectively, during SE is not a prerequisite for alleviation of epileptogenesis and development of epilepsy. In addition, a reduction of gamma and HI bands in the frontal and parietal cortex is not associated with EEG-recorded paroxysmal events after acute injection of LCM.
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Affiliation(s)
- Jana Tchekalarova
- Institute of Neurobiology, Bulgarian Academy of Sciences (BAS), Sofia, Bulgaria.
| | - Dimitrinka Atanasova
- Institute of Neurobiology, Bulgarian Academy of Sciences (BAS), Sofia, Bulgaria; Department of Anatomy, Faculty of Medicine, Trakia University, Stara Zagora, Bulgaria
| | - Lidia Kortenska
- Institute of Neurobiology, Bulgarian Academy of Sciences (BAS), Sofia, Bulgaria
| | - Nikolai Lazarov
- Department of Anatomy and Histology, Medical University of Sofia, Sofia 1431, Bulgaria
| | | | | | - Pencho Marinov
- Institute of Information and Communication Technologies, BAS, Sofia, Bulgaria
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Abstract
Evidence from both preclinical and clinical studies suggest the importance of zinc homeostasis in seizures/epilepsy. Undoubtedly, zinc, via modulation of a variety of targets, is necessary for maintaining the balance between neuronal excitation and inhibition, while an imbalance between excitation and inhibition underlies seizures. However, the relationship between zinc signaling and seizures/epilepsy is complex as both extracellular and intracellular zinc may produce either protective or detrimental effects. This review provides an overview of preclinical/behavioral, functional and molecular studies, as well as clinical data on the involvement of zinc in the pathophysiology and treatment of seizures/epilepsy. Furthermore, the potential of targeting elements associated with zinc signaling or homeostasis and zinc levels as a therapeutic strategy for epilepsy is discussed.
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Affiliation(s)
- Urszula Doboszewska
- Department of Animal Physiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Lublin, Poland.
| | - Katarzyna Młyniec
- Department of Pharmacobiology, Jagiellonian University Medical College, Kraków, Poland
| | - Aleksandra Wlaź
- Department of Pathophysiology, Medical University of Lublin, Lublin, Poland
| | - Ewa Poleszak
- Department of Applied Pharmacy, Medical University of Lublin, Lublin, Poland
| | - Gabriel Nowak
- Department of Pharmacobiology, Jagiellonian University Medical College, Kraków, Poland; Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Piotr Wlaź
- Department of Animal Physiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Lublin, Poland
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Kalozoumi G, Kel-Margoulis O, Vafiadaki E, Greenberg D, Bernard H, Soreq H, Depaulis A, Sanoudou D. Glial responses during epileptogenesis in Mus musculus point to potential therapeutic targets. PLoS One 2018; 13:e0201742. [PMID: 30114263 PMCID: PMC6095496 DOI: 10.1371/journal.pone.0201742] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 07/21/2018] [Indexed: 01/21/2023] Open
Abstract
The Mesio-Temporal Lobe Epilepsy syndrome is the most common form of intractable epilepsy. It is characterized by recurrence of focal seizures and is often associated with hippocampal sclerosis and drug resistance. We aimed to characterize the molecular changes occurring during the initial stages of epileptogenesis in search of new therapeutic targets for Mesio-Temporal Lobe Epilepsy. We used a mouse model obtained by intra-hippocampal microinjection of kainate and performed hippocampal whole genome expression analysis at 6h, 12h and 24h post-injection, followed by multilevel bioinformatics analysis. We report significant changes in immune and inflammatory responses, neuronal network reorganization processes and glial functions, predominantly initiated during status epilepticus at 12h and persistent after the end of status epilepticus at 24h post-kainate. Upstream regulator analysis highlighted Cyba, Cybb and Vim as central regulators of multiple overexpressed genes implicated in glial responses at 24h. In silico microRNA analysis indicated that miR-9, miR-19b, miR-129, and miR-223 may regulate the expression of glial-associated genes at 24h. Our data support the hypothesis that glial-mediated inflammatory response holds a key role during epileptogenesis, and that microglial cells may participate in the initial process of epileptogenesis through increased ROS production via the NOX complex.
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Affiliation(s)
- Georgia Kalozoumi
- Clinical Genomics and Pharmacogenomics Unit, 4 Department of Internal Medicine, Attikon Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | | | - Elizabeth Vafiadaki
- Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - David Greenberg
- The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | | | - Hermona Soreq
- The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Antoine Depaulis
- INSERM, Grenoble, France
- Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France
- CHU de Grenoble, Hôpital Michallon, Grenoble, France
| | - Despina Sanoudou
- Clinical Genomics and Pharmacogenomics Unit, 4 Department of Internal Medicine, Attikon Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
- Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
- * E-mail:
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12
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Torres CM, Siebert M, Bock H, Mota SM, Castan JU, Scornavacca F, de Castro LA, Saraiva-Pereira ML, Bianchin MM. Tyrosine receptor kinase B gene variants (NTRK2 variants) are associated with depressive disorders in temporal lobe epilepsy. Epilepsy Behav 2017; 71:65-72. [PMID: 28550723 DOI: 10.1016/j.yebeh.2017.03.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 03/07/2017] [Accepted: 03/26/2017] [Indexed: 02/07/2023]
Abstract
RATIONALE Psychiatric comorbidities are highly prevalent in epilepsy, adding an important burden to the disease and profoundly affecting the quality of life of these individuals. Patients with temporal lobe epilepsy (TLE) are especially at risk to develop depression and several lines of evidence suggest that the association of depression with epilepsy might be related to common biological substrates. In this study, we test whether NTRK2 allele variants are associated with mood disorders or depressive disorders in patients with TLE. METHODS An association study of 163 patients with TLE. The NTRK2 variants studied were rs1867283, rs10868235, rs1147198, rs11140800, rs1187286, rs2289656, rs1624327, rs1443445, rs3780645, and rs2378672. All patients were submitted to the Structured Clinical Interview for DSM-IV (SCID) and epilepsy patients with mood disorders or depressive disorders were compared to epilepsy patients without mood disorders or depressive disorders. RESULTS In our TLE cohort, 76 patients (46.6%) showed mood disorders. After logistic regression, independent risk factors for mood disorders in TLE were female sex, presence of concomitant anxiety disorders, and genetic variations in rs1867283 and rs10868235 NTRK2 variants. Depressive disorders accounted for this results and independent variables associated with depressive disorders in TLE were female sex (OR=2.59; 95%CI=1.15-5.82; p=0.021), presence of concomitant anxiety disorders (OR=3.72; 95%CI=1.71-8.06; p=0.001) or psychotic disorders (OR=3.86; 95%CI=1.12-13.25; p=0.032), A/A genotype in the rs1867283 NTRK2 gene (OR=3.06; 95%CI=1.25-7.50; p=0.015) and C/C genotype in the rs10868235 NTRK2 gene (OR=3.54; 1.55-8.08; p=0.003). Similarly, these genotypes also remained independently and significantly associated with depressive disorders when patients with depressive disorders were compared to TLE patients without any psychiatric comorbidity. CONCLUSION In the present study, female sex, presence of concomitant anxiety or psychotic disorders, and specific allelic variations in the NTRK2 gene were independently associated with mood disorders or depressive disorders in TLE. If our results were confirmed, variants in the NTRK2 gene could be considered as risk factors or biomarkers for depressive disorders in patients with TLE.
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Affiliation(s)
- Carolina Machado Torres
- Medical Sciences, Universidade Federal do Rio Grande do Sul, Brazil; Basic Research and Advanced Investigations in Neurology (BRAIN), Experimental Research Centre, Centro de Tratamento de Epilepsia Refratária (CETER), Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Brazil
| | - Marina Siebert
- Laboratory of Genetic Identification, Experimental Research Centre, Hospital de Clinicas de Porto Alegre, Brazil
| | - Hugo Bock
- Laboratory of Genetic Identification, Experimental Research Centre, Hospital de Clinicas de Porto Alegre, Brazil
| | - Suelen Mandelli Mota
- Basic Research and Advanced Investigations in Neurology (BRAIN), Experimental Research Centre, Centro de Tratamento de Epilepsia Refratária (CETER), Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Brazil
| | - Juliana Unis Castan
- Basic Research and Advanced Investigations in Neurology (BRAIN), Experimental Research Centre, Centro de Tratamento de Epilepsia Refratária (CETER), Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Brazil
| | | | - Luiza Amaral de Castro
- Basic Research and Advanced Investigations in Neurology (BRAIN), Experimental Research Centre, Centro de Tratamento de Epilepsia Refratária (CETER), Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Brazil
| | - Maria Luiza Saraiva-Pereira
- Laboratory of Genetic Identification, Experimental Research Centre, Hospital de Clinicas de Porto Alegre, Brazil
| | - Marino Muxfeldt Bianchin
- Medical Sciences, Universidade Federal do Rio Grande do Sul, Brazil; Basic Research and Advanced Investigations in Neurology (BRAIN), Experimental Research Centre, Centro de Tratamento de Epilepsia Refratária (CETER), Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Brazil.
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13
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Martínez-Levy GA, Rocha L, Rodríguez-Pineda F, Alonso-Vanegas MA, Nani A, Buentello-García RM, Briones-Velasco M, San-Juan D, Cienfuegos J, Cruz-Fuentes CS. Increased Expression of Brain-Derived Neurotrophic Factor Transcripts I and VI, cAMP Response Element Binding, and Glucocorticoid Receptor in the Cortex of Patients with Temporal Lobe Epilepsy. Mol Neurobiol 2017; 55:3698-3708. [PMID: 28527108 DOI: 10.1007/s12035-017-0597-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 05/03/2017] [Indexed: 12/19/2022]
Abstract
A body of evidence supports a relevant role of brain-derived neurotrophic factor (BDNF) in temporal lobe epilepsy (TLE). Magnetic resonance data reveal that the cerebral atrophy extends to regions that are functionally and anatomically connected with the hippocampus, especially the temporal cortex. We previously reported an increased expression of BDNF messenger for the exon VI in the hippocampus of temporal lobe epilepsy patients compared to an autopsy control group. Altered levels of this particular transcript were also associated with pre-surgical use of certain psychotropic. We extended here our analysis of transcripts I, II, IV, and VI to the temporal cortex since this cerebral region holds intrinsic communication with the hippocampus and is structurally affected in patients with TLE. We also assayed the cyclic adenosine monophosphate response element-binding (CREB) and glucocorticoid receptor (GR) genes as there is experimental evidence of changes in their expression associated with BDNF and epilepsy. TLE and pre-surgical pharmacological treatment were considered as the primary clinical independent variables. Transcripts BDNF I and BDNF VI increased in the temporal cortex of patients with pharmacoresistant TLE. The expression of CREB and GR expression follow the same direction. Pre-surgical use of selective serotonin reuptake inhibitors, carbamazepine (CBZ) and valproate (VPA), was associated with the differential expression of specific BDNF transcripts and CREB and GR genes. These changes could have functional implication in the plasticity mechanisms related to temporal lobe epilepsy.
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Affiliation(s)
- G A Martínez-Levy
- Department of Genetics, National Institute of Psychiatry "Ramón de la Fuente Muñiz" (INPRFM), Mexico City, Mexico
| | - L Rocha
- Department of Pharmacobiology, Center for Research and Advanced Studies, CINVESTAV, Mexico City, Mexico
| | - F Rodríguez-Pineda
- Department of Genetics, National Institute of Psychiatry "Ramón de la Fuente Muñiz" (INPRFM), Mexico City, Mexico
| | - M A Alonso-Vanegas
- Neurosurgery Section, National Institute of Neurology and Neurosurgery "Manuel Velasco Suárez" (INNNMVS), Mexico City, Mexico
| | - A Nani
- Department of Genetics, National Institute of Psychiatry "Ramón de la Fuente Muñiz" (INPRFM), Mexico City, Mexico
| | - R M Buentello-García
- Neurosurgery Section, National Institute of Neurology and Neurosurgery "Manuel Velasco Suárez" (INNNMVS), Mexico City, Mexico
| | - M Briones-Velasco
- Department of Genetics, National Institute of Psychiatry "Ramón de la Fuente Muñiz" (INPRFM), Mexico City, Mexico
| | - D San-Juan
- Clinical Research Department, National Institute of Neurology and Neurosurgery "Manuel Velasco Suárez" (INNNMVS), Mexico City, Mexico
| | - J Cienfuegos
- Neurosurgery Section, National Institute of Neurology and Neurosurgery "Manuel Velasco Suárez" (INNNMVS), Mexico City, Mexico
| | - C S Cruz-Fuentes
- Department of Genetics, National Institute of Psychiatry "Ramón de la Fuente Muñiz" (INPRFM), Mexico City, Mexico.
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14
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Martínez-Levy GA, Rocha L, Lubin FD, Alonso-Vanegas MA, Nani A, Buentello-García RM, Pérez-Molina R, Briones-Velasco M, Recillas-Targa F, Pérez-Molina A, San-Juan D, Cienfuegos J, Cruz-Fuentes CS. Increased expression of BDNF transcript with exon VI in hippocampi of patients with pharmaco-resistant temporal lobe epilepsy. Neuroscience 2015; 314:12-21. [PMID: 26621122 DOI: 10.1016/j.neuroscience.2015.11.046] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 11/18/2015] [Accepted: 11/19/2015] [Indexed: 11/30/2022]
Abstract
A putative role of the brain-derived neurotrophic factor (BDNF) in epilepsy has emerged from in vitro and animal models, but few studies have analyzed human samples. We assessed the BDNF expression of transcripts with exons I (BDNFI), II (BDNFII), IV (BDNFIV) and VI (BDNFVI) and methylation levels of promoters 4 and 6 in the hippocampi of patients with pharmaco-resistant temporal lobe epilepsy (TLE) (n=24). Hippocampal sclerosis (HS) and pre-surgical pharmacological treatment were considered as clinical independent variables. A statistical significant increase for the BDNFVI (p<0.05) was observed in TLE patients compared to the autopsy control group (n=8). BDNFVI was also increased in anxiety/depression TLE (N=4) when compared to autopsies or to the remaining group of patients (p<0.05). In contrast, the use of the antiepileptic drug Topiramate (TPM) (N=3) was associated to a decrease in BDNFVI expression (p<0.05) when compared to the remaining group of patients. Methylation levels at the BDNF promoters 4 and 6 were similar between TLE and autopsies and in relation to the use of either Sertraline (SRT) or TPM. These results suggest an up-regulated expression of a specific BDNF transcript in patients with TLE, an effect that seems to be dependent on the use of specific drugs.
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Affiliation(s)
- G A Martínez-Levy
- Department of Genetics, National Institute of Psychiatry "Ramón de la Fuente Muñiz" (INPRFM), Mexico DF, Mexico
| | - L Rocha
- Department of Pharmacobiology, Center for Research and Advanced Studies (CINVESTAV), Mexico City, Mexico
| | - F D Lubin
- Department of Neurobiology, Lubin Lab, University at Birmingham in Alabama, USA
| | - M A Alonso-Vanegas
- Neurosurgery Section, National Institute of Neurology and Neurosurgery "Manuel Velasco Suárez" (INNNMVS), Mexico City, Mexico
| | - A Nani
- Department of Genetics, National Institute of Psychiatry "Ramón de la Fuente Muñiz" (INPRFM), Mexico DF, Mexico
| | - R M Buentello-García
- Neurosurgery Section, National Institute of Neurology and Neurosurgery "Manuel Velasco Suárez" (INNNMVS), Mexico City, Mexico
| | - R Pérez-Molina
- Institute of Cell Physiology, National University of Mexico, UNAM, Mexico City, Mexico
| | - M Briones-Velasco
- Department of Genetics, National Institute of Psychiatry "Ramón de la Fuente Muñiz" (INPRFM), Mexico DF, Mexico
| | - F Recillas-Targa
- Institute of Cell Physiology, National University of Mexico, UNAM, Mexico City, Mexico
| | - A Pérez-Molina
- Department of Genetics, National Institute of Psychiatry "Ramón de la Fuente Muñiz" (INPRFM), Mexico DF, Mexico
| | - D San-Juan
- Clinical Research Department, National Institute of Neurology and Neurosurgery "Manuel Velasco Suárez" (INNNMVS), Mexico City, Mexico
| | - J Cienfuegos
- Neurosurgery Section, National Institute of Neurology and Neurosurgery "Manuel Velasco Suárez" (INNNMVS), Mexico City, Mexico
| | - C S Cruz-Fuentes
- Department of Genetics, National Institute of Psychiatry "Ramón de la Fuente Muñiz" (INPRFM), Mexico DF, Mexico.
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15
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Huang Y, Wu X, Guo J, Yuan J. Myocyte-specific enhancer binding factor 2A expression is downregulated during temporal lobe epilepsy. Int J Neurosci 2015; 126:786-96. [PMID: 26439092 DOI: 10.3109/00207454.2015.1062003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Myocyte-specific enhancer binding factor 2A (MEF2A) is a multifunctional nuclear protein that regulates synaptogenesis, dendritic morphogenesis, and neuronal survival. This study aimed to investigate the expression pattern of MEF2A in epileptogenic processes. MEF2A expression was detected in 20 temporal neocortex tissue samples from patients with temporal lobe epilepsy (TLE) and 20 samples from trauma patients without epilepsy by real-time quantitative polymerase chain reaction, immunohistochemistry, double-label immunofluorescent staining, and western blot analysis. In addition, the expression patterns of MEF2A in the hippocampus and adjacent cortex of a lithium-pilocarpine-induced TLE rat model and control rats were examined. MEF2A was found to be expressed in the nuclei of neurons but not in the dendrites of neurons and astrocytes. MEF2A expression was significantly downregulated in temporal neocortex of humans and rats with TLE compared to the control groups. In addition, in the lithium-pilocarpine-induced TLE model, MEF2A expression dynamically decreased within 2 months. Taken together, these data suggest that MEF2A is involved in the pathogenesis of TLE.
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Affiliation(s)
- Yunyi Huang
- a Department of Neurology, The Second Affiliated Hospital, Chongqing Medical University , Yangmei Chen , China
| | - Xuling Wu
- a Department of Neurology, The Second Affiliated Hospital, Chongqing Medical University , Yangmei Chen , China
| | - Jing Guo
- a Department of Neurology, The Second Affiliated Hospital, Chongqing Medical University , Yangmei Chen , China
| | - Jinxian Yuan
- a Department of Neurology, The Second Affiliated Hospital, Chongqing Medical University , Yangmei Chen , China
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16
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Huang Y. Up-regulated cytoplasmic FMRP-interacting protein 1 in intractable temporal lobe epilepsy patients and a rat model. Int J Neurosci 2015; 126:542-551. [PMID: 26000921 DOI: 10.3109/00207454.2015.1038711] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cytoplasmic FMRP-interacting protein 1 (CYFIP1) is a multifunctional protein which expresses highly at excitatory synapses and can locally regulate actin cytoskeletal dynamics, spine morphology and synaptic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor lateral diffusion. Altered synaptic actin plays a role in the pathogenesis of epilepsy. The aim of this study was to investigate the expression pattern of CYFIP1 in temporal lobe epilepsy (TLE). Protein and mRNA expression levels were compared in temporal lobe tissue from patients with TLE versus trauma patients without TLE using quantitative real-time polymerase chain reaction (qRT-PCR), double-label immunofluorescence and Western blot analysis. We have further determined the expression pattern of Cyfip1 mRNA and protein in the hippocampus and adjacent cortex of a common rat model of TLE, lithium-pilocarpine treatment, compared to control rats. CYFIP1 expression was significantly up-regulated in the temporal neocortex of patients with intractable TLE and pilocarpine-treated rats compared to control groups. CYFIP1 localizes to the cytoplasm of neurons, and is not expressed in the astrocytes. Furthermore, CYFIP1 expression levels increased significantly in the two months after pilocarpine treatment, which corresponds to the period of epileptogenesis. Thus, our results indicate that CYFIP1 may be involved in the pathogenesis of TLE.
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Affiliation(s)
- Yunyi Huang
- a Department of Neurology, The Second Affiliated Hospital , Chongqing Medical University , Chongqing , China
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17
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Depaulis A, Hamelin S. Animal models for mesiotemporal lobe epilepsy: The end of a misunderstanding? Rev Neurol (Paris) 2015; 171:217-26. [DOI: 10.1016/j.neurol.2015.01.558] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 01/20/2015] [Indexed: 01/24/2023]
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18
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Kandratavicius L, Hallak JE, Leite JP. What are the similarities and differences between schizophrenia and schizophrenia-like psychosis of epilepsy? A neuropathological approach to the understanding of schizophrenia spectrum and epilepsy. Epilepsy Behav 2014; 38:143-7. [PMID: 24508393 DOI: 10.1016/j.yebeh.2014.01.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 01/10/2014] [Accepted: 01/12/2014] [Indexed: 10/25/2022]
Abstract
Temporal lobe epilepsy (TLE) and psychosis coexist more frequently than chance would predict. In this short review, clinical and neuropathological findings of schizophrenia, TLE, and psychosis of epilepsy are described to enhance our understanding of the noncoincidental association between these conditions. In addition, psychosis of epilepsy was included for the first time in the Diagnostic and Statistical Manual of Mental Disorders (DSM), in the recently launched 5th edition, and improvement in diagnostic criteria was highlighted. Since the hippocampus has long been considered an anatomical area involved in the pathophysiology of TLE and schizophrenia, neuropathological studies of psychoses of epilepsy may contribute to our understanding of the pathophysiology of psychosis in general. The discovery of shared mechanisms and/or affected neurochemicals in TLE and schizophrenia might disclose important clues on the vulnerability of patients with TLE to psychotic symptoms and be an opportunity for new treatment development.
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Affiliation(s)
- Ludmyla Kandratavicius
- Ribeirao Preto School of Medicine, Department of Neurosciences and Behavior, University of Sao Paulo (USP), Brazil; Center for Interdisciplinary Research on Applied Neurosciences (NAPNA), USP, Brazil
| | - Jaime Eduardo Hallak
- Ribeirao Preto School of Medicine, Department of Neurosciences and Behavior, University of Sao Paulo (USP), Brazil; Center for Interdisciplinary Research on Applied Neurosciences (NAPNA), USP, Brazil; National Institute of Science and Technology in Translational Medicine (INCT-TM-CNPq), Brazil
| | - Joao Pereira Leite
- Ribeirao Preto School of Medicine, Department of Neurosciences and Behavior, University of Sao Paulo (USP), Brazil; Center for Interdisciplinary Research on Applied Neurosciences (NAPNA), USP, Brazil.
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19
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Varvel NH, Jiang J, Dingledine R. Candidate drug targets for prevention or modification of epilepsy. Annu Rev Pharmacol Toxicol 2014; 55:229-47. [PMID: 25196047 DOI: 10.1146/annurev-pharmtox-010814-124607] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Epilepsy is a prevalent neurological disorder afflicting nearly 50 million people worldwide. The disorder is characterized clinically by recurrent spontaneous seizures attributed to abnormal synchrony of brain neurons. Despite advances in the treatment of epilepsy, nearly one-third of patients are resistant to current therapies, and the underlying mechanisms whereby a healthy brain becomes epileptic remain unresolved. Therefore, researchers have a major impetus to identify and exploit new drug targets. Here we distinguish between epileptic effectors, or proteins that set the seizure threshold, and epileptogenic mediators, which control the expression or functional state of the effector proteins. Under this framework, we then discuss attempts to regulate the mediators to control epilepsy. Further insights into the complex processes that render the brain susceptible to seizures and the identification of novel mediators of these processes will lead the way to the development of drugs to modify disease outcome and, potentially, to prevent epileptogenesis.
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Affiliation(s)
- Nicholas H Varvel
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322;
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20
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Kandratavicius L, Hallak JE, Carlotti CG, Assirati JA, Leite JP. Neurotrophin receptors expression in mesial temporal lobe epilepsy with and without psychiatric comorbidities and their relation with seizure type and surgical outcome. Acta Neuropathol Commun 2014; 2:81. [PMID: 25027171 PMCID: PMC4149196 DOI: 10.1186/s40478-014-0081-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 06/29/2014] [Indexed: 12/30/2022] Open
Abstract
Epilepsy and psychiatric comorbidities are frequently associated, but their common biological substrate is unknown. We have previously reported altered structural elements and neurotrophins (NTs) expression in mesial temporal lobe epilepsy (MTLE) patients with psychiatric comorbidities. NTs receptors can regulate neurotransmission and promote neuroplasticity, being important candidates in the regulation and manifestation of psychopatological states and seizure-related events. MTLE hippocampi of subjects without psychiatric history, MTLE + major depression, MTLE + interictal psychosis derived from epilepsy surgery, and control necropsies were investigated for p75NTR, TrkB, TrkA, and TrkC immunohistochemistry. Increased expression of p75NTR, decreased TrkA, unaltered TrkC, and complex alterations involving TrkB expression were seen in MTLE groups. Increased TrkB expression in patients without complete seizure remission and in those with secondarily generalized seizures was seen. Decreased p75NTR expression associated with interictal psychosis, and increased TrkB in those with psychosis or major depression was also reported, although their p75NTR/TrkB ratios were lower than in MTLE without psychiatric comorbidities. Our results provide evidence of alterations in expression of NTs receptors in the epileptogenic hippocampus that are differentially modulated in presence of psychiatric comorbidities. As already explored in animal models, even in chronic human MTLE increased TrkB expression, among other NT receptors alterations, may play a major role in seizure type, frequency and surgery outcome.
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21
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Neurotrophins in mesial temporal lobe epilepsy with and without psychiatric comorbidities. J Neuropathol Exp Neurol 2013; 72:1029-42. [PMID: 24128677 DOI: 10.1097/nen.0000000000000002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Despite the strong association between epilepsy and psychiatric comorbidities, data on clinicopathologic correlations are scant. We previously reported differential mossy fiber sprouting (MFS) in mesial temporal lobe epilepsy (MTLE) patients with psychosis (MTLE + P) and major depression (MTLE + D). Because neurotrophins (NTs) can promote MFS, here, we investigated MFS, neuronal density and immunoreactivity for the NT nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neurotrophin 3 (NT3) in hippocampi of 14 MTLE patients without a psychiatric history, 13 MTLE + D, 13 MTLE + P, and 10 control necropsies. Mossy fiber sprouting correlated with granular layer NGF immunoreactivity and seizure frequency. Patients with secondarily generalized seizures exhibited less NGF immunoreactivity versus patients with complex partial seizures. There was greater NT immunoreactivity in MTLE versus control groups but lesser NT immunoreactivity in MTLE + P versus MTLE patients; these findings correlated with neuropsychologic scores. Patients with MTLE + D taking fluoxetine showed greater BDNF immunoreactivity than those not taking fluoxetine; MTLE + P patients taking haloperidol had decreased neuronal density and immunoreactivity for NGF and BDNF in specific subfields versus those not taking haloperidol. There were no differences in NT3 immunoreactivity among the groups. These findings support a close association between MFS and NT expression in the hippocampi of MTLE patients and suggest that distinct structural and neurochemical milieu may contribute to the genesis or maintenance of psychiatric comorbidities in MTLE.
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22
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Scharfman HE, MacLusky NJ. Differential regulation of BDNF, synaptic plasticity and sprouting in the hippocampal mossy fiber pathway of male and female rats. Neuropharmacology 2013; 76 Pt C:696-708. [PMID: 23660230 DOI: 10.1016/j.neuropharm.2013.04.029] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 04/10/2013] [Accepted: 04/15/2013] [Indexed: 10/26/2022]
Abstract
Many studies have described potent effects of BDNF, 17β-estradiol or androgen on hippocampal synapses and their plasticity. Far less information is available about the interactions between 17β-estradiol and BDNF in hippocampus, or interactions between androgen and BDNF in hippocampus. Here we review the regulation of BDNF in the mossy fiber pathway, a critical part of hippocampal circuitry. We discuss the emerging view that 17β-estradiol upregulates mossy fiber BDNF synthesis in the adult female rat, while testosterone exerts a tonic suppression of mossy fiber BDNF levels in the adult male rat. The consequences are interesting to consider: in females, increased excitability associated with high levels of BDNF in mossy fibers could improve normal functions of area CA3, such as the ability to perform pattern completion. However, memory retrieval may lead to anxiety if stressful events are recalled. Therefore, the actions of 17β-estradiol on the mossy fiber pathway in females may provide a potential explanation for the greater incidence of anxiety-related disorders and post-traumatic stress syndrome (PTSD) in women relative to men. In males, suppression of BDNF-dependent plasticity in the mossy fibers may be protective, but at the 'price' of reduced synaptic plasticity in CA3. This article is part of the Special Issue entitled 'BDNF Regulation of Synaptic Structure, Function, and Plasticity'.
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Affiliation(s)
- Helen E Scharfman
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, 140 Old Orangeburg Rd., Bldg. 35, Orangeburg, NY 10962, USA; Department of Child & Adolescent Psychiatry, New York University Langone Medical Center, New York, NY 10016, USA; Department of Physiology & Neuroscience, New York University Langone Medical Center, New York, NY 10016, USA; Department of Psychiatry, New York University Langone Medical Center, New York, NY 10016, USA.
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23
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Cardamone L, Salzberg MR, O'Brien TJ, Jones NC. Antidepressant therapy in epilepsy: can treating the comorbidities affect the underlying disorder? Br J Pharmacol 2013; 168:1531-54. [PMID: 23146067 PMCID: PMC3605864 DOI: 10.1111/bph.12052] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 10/24/2012] [Accepted: 10/29/2012] [Indexed: 12/20/2022] Open
Abstract
There is a high incidence of psychiatric comorbidity in people with epilepsy (PWE), particularly depression. The manifold adverse consequences of comorbid depression have been more clearly mapped in recent years. Accordingly, considerable efforts have been made to improve detection and diagnosis, with the result that many PWE are treated with antidepressant drugs, medications with the potential to influence both epilepsy and depression. Exposure to older generations of antidepressants (notably tricyclic antidepressants and bupropion) can increase seizure frequency. However, a growing body of evidence suggests that newer ('second generation') antidepressants, such as selective serotonin reuptake inhibitors or serotonin-noradrenaline reuptake inhibitors, have markedly less effect on excitability and may lead to improvements in epilepsy severity. Although a great deal is known about how antidepressants affect excitability on short time scales in experimental models, little is known about the effects of chronic antidepressant exposure on the underlying processes subsumed under the term 'epileptogenesis': the progressive neurobiological processes by which the non-epileptic brain changes so that it generates spontaneous, recurrent seizures. This paper reviews the literature concerning the influences of antidepressants in PWE and in animal models. The second section describes neurobiological mechanisms implicated in both antidepressant actions and in epileptogenesis, highlighting potential substrates that may mediate any effects of antidepressants on the development and progression of epilepsy. Although much indirect evidence suggests the overall clinical effects of antidepressants on epilepsy itself are beneficial, there are reasons for caution and the need for further research, discussed in the concluding section.
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Affiliation(s)
- L Cardamone
- Department of Medicine (RMH), University of Melbourne, Melbourne, Victoria, Australia
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24
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Grabenstatter HL, Russek SJ, Brooks-Kayal AR. Molecular pathways controlling inhibitory receptor expression. Epilepsia 2013; 53 Suppl 9:71-8. [PMID: 23216580 DOI: 10.1111/epi.12036] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Epilepsy is a disease of complex etiology, and multiple molecular mechanisms contribute to its development. Temporal lobe epilepsy (TLE) may result from an initial precipitating event such as hypoxia, head injury, or prolonged seizure (i.e., status epilepticus [SE]), that is followed by a latent period of months to years before spontaneous seizures occur. γ-Aminobutyric acid (GABA)(A) receptor (GABA(A) R) subunit changes occur during this latent period and may persist following the onset of spontaneous seizures. Research into the molecular mechanisms regulating these changes and potential targets for intervention to reverse GABA(A) R subunit alterations have uncovered seizure-induced pathways that contribute to epileptogenesis. Several growth or transcription factors are known to be activated by SE, including (but not limited to): brain-derived neurotrophic factor (BDNF), cAMP response element binding protein (CREB), inducible cAMP early repressor (ICER), and early growth response factors (Egrs). Results of multiple studies suggest that these factors transcriptionally regulate GABA(A) R subunit gene expression in a way that is pertinent to the development of epilepsy. This article focuses on these signaling elements and describes their possible roles in gene regulatory pathways that may be critical in the development of chronic epilepsy.
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Affiliation(s)
- Heidi L Grabenstatter
- Translational Epilepsy Program, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
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25
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Zhu Q, Wang L, Xiao Z, Xiao F, Luo J, Zhang X, Peng X, Wang X, Sun H. Decreased expression of Ras-GRF1 in the brain tissue of the intractable epilepsy patients and experimental rats. Brain Res 2013. [DOI: 10.1016/j.brainres.2012.11.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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26
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Sakharnova TA, Vedunova MV, Mukhina IV. Brain-derived neurotrophic factor (BDNF) and its role in the functioning of the central nervous system. NEUROCHEM J+ 2012. [DOI: 10.1134/s1819712412030129] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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27
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Role of Endoplasmic Reticulum Stress in the Amygdaloid Kindling Model of Rats. Neurochem Res 2011; 36:1834-9. [DOI: 10.1007/s11064-011-0501-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/07/2011] [Indexed: 10/18/2022]
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28
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Abstract
It has been known for some time that brain-derived neurotrophic factor (BDNF) is critical to normal development of the CNS, and more recently, studies also have documented the ability of BDNF to modify adult CNS structure and function. Therefore, it is no surprise that BDNF has been linked to diseases, such as epilepsy, which may involve abnormal cortical development or altered brain structure and function after maturity. This review evaluates the evidence, particularly from recent studies, that BDNF contributes to the development of temporal lobe epilepsy (TLE).
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29
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Wu L, Peng J, Wei C, Liu G, Wang G, Li K, Yin F. Characterization, using comparative proteomics, of differentially expressed proteins in the hippocampus of the mesial temporal lobe of epileptic rats following treatment with valproate. Amino Acids 2010; 40:221-38. [PMID: 20524136 DOI: 10.1007/s00726-010-0638-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2009] [Accepted: 05/19/2010] [Indexed: 12/13/2022]
Abstract
The objective of the study was to explore the pathogenesis of mesial temporal lobe epilepsy (MTLE) and the mechanism of valproate administration in the early stage of MTLE development. We performed a global comparative analysis and function classification of differentially expressed proteins using proteomics. MTLE models of developmental rats were induced by lithium-pilocarpine. Proteins in the hippocampus were separated by 2-DE technology. PDQuest software was used to analyze 2-DE images, and MALDI-TOF-MS was used to identify the differentially expressed proteins. Western blot was used to determine the differential expression levels of synapse-related proteins synapsin-1, dynamin-1 and neurogranin in both MTLE rat and human hippocampus. A total of 48 differentially expressed proteins were identified between spontaneous and non-spontaneous MTLE rats, while 41 proteins between MTLE rats and post valproate-treatment rats were identified. All of the proteins can be categorized into several groups by biological functions: synaptic and neurotransmitter release, cytoskeletal structure and dynamics, cell junctions, energy metabolism and mitochondrial function, molecular chaperones, signal regulation and others. Western blot results were similar to the changes noted in 2-DE. The differentially expressed proteins, especially the proteins related to synaptic and neurotransmitter release function, such as synapsin-1, dynamin-1 and neurogranin, are probably involved in the mechanism of MTLE and the pharmacological effect of valproate. These findings may provide important clues to elucidate the mechanism of chronic MTLE and to identify an optimum medication intervention time and new biomarkers for the development of pharmacological therapies targeted at epilepsy.
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Affiliation(s)
- Liwen Wu
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha 410008, Hunan, People's Republic of China
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Midkine, heparin-binding growth factor, blocks kainic acid-induced seizure and neuronal cell death in mouse hippocampus. BMC Neurosci 2010; 11:42. [PMID: 20346117 PMCID: PMC2861065 DOI: 10.1186/1471-2202-11-42] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Accepted: 03/26/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Midkine (MK), a member of the heparin-binding growth factor family, which includes MK and pleiotrophin, is known to possess neurotrophic and neuroprotective properties in the central nervous system. Previous studies have shown that MK is an effective neuroprotective agent in reducing retinal degeneration caused by excessive light and decreasing hippocampal neuronal death in ischemic gerbil brain. The present study was undertaken to investigate whether MK acts as an anticonvulsant in kainic acid (KA)-induced seizure in mouse and blocks KA-mediated neuronal cell death in hippocampus. RESULTS Increased expression of MK was found in hippocampus of mouse following seizures induced by intracerebroventricular injection of KA, and MK expression was found in glial fibrillary acidic protein (GFAP)-positive astrocytes. Concurrent injection of MK and KA attenuated KA-induced seizure activity and cell death of hippocampal neurons including pyramidal cells and glutamic acid decarboxylase 67 (GAD67)-positive GABAergic interneurons in the CA3 and hilar area. CONCLUSION The results of the present study indicate that MK functions as an anticonvulsant and neuroprotective agent in hippocampus during KA-induced seizures.
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Wong-Goodrich SJE, Glenn MJ, Mellott TJ, Liu YB, Blusztajn JK, Williams CL. Water maze experience and prenatal choline supplementation differentially promote long-term hippocampal recovery from seizures in adulthood. Hippocampus 2010; 21:584-608. [PMID: 20232399 DOI: 10.1002/hipo.20783] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/12/2010] [Indexed: 12/16/2022]
Abstract
Status epilepticus (SE) in adulthood dramatically alters the hippocampus and produces spatial learning and memory deficits. Some factors, like environmental enrichment and exercise, may promote functional recovery from SE. Prenatal choline supplementation (SUP) also protects against spatial memory deficits observed shortly after SE in adulthood, and we have previously reported that SUP attenuates the neuropathological response to SE in the adult hippocampus just 16 days after SE. It is unknown whether SUP can ameliorate longer-term cognitive and neuropathological consequences of SE, whether repeatedly engaging the injured hippocampus in a cognitive task might facilitate recovery from SE, and whether our prophylactic prenatal dietary treatment would enable the injured hippocampus to more effectively benefit from cognitive rehabilitation. To address these issues, adult offspring from rat dams that received either a control (CON) or SUP diet on embryonic days 12-17 first received training on a place learning water maze task (WM) and were then administered saline or kainic acid (KA) to induce SE. Rats then either remained in their home cage, or received three additional WM sessions at 3, 6.5, and 10 weeks after SE to test spatial learning and memory retention. Eleven weeks after SE, the brains were analyzed for several hippocampal markers known to be altered by SE. SUP attenuated SE-induced spatial learning deficits and completely rescued spatial memory retention by 10 weeks post-SE. Repeated WM experience prevented SE-induced declines in glutamic acid decarboxylase (GAD) and dentate gyrus neurogenesis, and attenuated increased glial fibrilary acidic protein (GFAP) levels. Remarkably, SUP alone was similarly protective to an even greater extent, and SUP rats that were water maze trained after SE showed reduced hilar migration of newborn neurons. These findings suggest that prophylactic SUP is protective against the long-term cognitive and neuropathological effects of KA-induced SE, and that rehabilitative cognitive enrichment may be partially beneficial.
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Kandratavicius L, Monteiro MR, Silva RADVD, Leite JP. Neurotrofinas na epilepsia do lobo temporal. ACTA ACUST UNITED AC 2010. [DOI: 10.1590/s1676-26492010000100002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUÇÃO: A neurotrofinas NGF, BDNF, NT-3 e NT-4 são os principais representantes da família das neurotrofinas no sistema nervoso central de mamíferos. Estão presentes em estágios específicos do crescimento e sobrevivência neuronal como a divisão celular, diferenciação e axogênese e também nos processos naturais de morte celular neuronal. A atividade biológica das neurotrofinas é mediada pelos receptores de tropomiosina quinase Trk. NGF ativa principalmente os receptores TrkA, BDNF e NT-4 interagem com os receptores TrkB e NT-3 com TrkC. Todas as NTs também podem se ligar, com menor afinidade, ao receptor p75NTR. Nesta breve revisão serão levantadas as principais evidências sobre o papel e expressão das principais neurotrofinas no hipocampo, com ênfase nas alterações que ocorrem em modelos animais de epilepsia. RESULTADOS: As neurotrofinas parecem ter um papel chave na plasticidade sináptica relacionada à epilepsia, onde elas poderiam agir tanto como fatores promotores da epileptogênese quanto como substâncias anti-epiléptogênicas endógenas. Além disso a expressão dos genes que codificam os fatores neurotróficos e seus receptores pode ser alterada pela atividade de crises em diversos modelos de epilepsia. CONCLUSÃO: Vários estudos têm demonstrado a relação entre a expressão das neurotrofinas e as alterações na plasticidade dos circuitos neuronais que ocorrem após danos cerebrais, tais como a epilepsia. O conhecimento das alterações na expressão das neurotrofinas na plasticidade neuronal pode nos auxiliar a entender como estas moléculas participam dos mecanismos epileptogênicos e dessa forma, dar início ao estudo de novas terapias e ao desenvolvimento de novas drogas que auxiliem no tratamento da epilepsia.
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Danzer SC, Kotloski RJ, Walter C, Hughes M, McNamara JO. Altered morphology of hippocampal dentate granule cell presynaptic and postsynaptic terminals following conditional deletion of TrkB. Hippocampus 2008; 18:668-78. [PMID: 18398849 DOI: 10.1002/hipo.20426] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Dentate granule cells play a critical role in the function of the entorhinal-hippocampal circuitry in health and disease. Dentate granule cells are situated to regulate the flow of information into the hippocampus, a structure required for normal learning and memory. Correspondingly, impaired granule cell function leads to memory deficits, and, interestingly, altered granule cell connectivity may contribute to the hyperexcitability of limbic epilepsy. It is important, therefore, to understand the molecular determinants of synaptic connectivity of these neurons. Brain-derived neurotrophic factor and its receptor TrkB are expressed at high levels in the dentate gyrus (DG) of the hippocampus, and are implicated in regulating neuronal development, neuronal plasticity, learning, and the development of epilepsy. Whether and how TrkB regulates granule cell structure, however, is incompletely understood. To begin to elucidate the role of TrkB in regulating granule cell morphology, here we examine conditional TrkB knockout mice crossed to mice expressing green fluorescent protein in subsets of dentate granule cells. In stratum lucidum, where granule cell mossy fiber axons project, the density of giant mossy fiber boutons was unchanged, suggesting similar output to CA3 pyramidal cell targets. However, filopodial extensions of giant boutons, which contact inhibitory interneurons, were increased in number in TrkB knockout mice relative to wildtype controls, predicting enhanced feedforward inhibition of CA3 pyramidal cells. In knockout animals, dentate granule cells possessed fewer primary dendrites and enlarged dendritic spines, indicative of disrupted excitatory synaptic input to the granule cells. Together, these findings demonstrate that TrkB is required for development and/or maintenance of normal synaptic connectivity of the granule cells, thereby implying an important role for TrkB in the function of the granule cells and hippocampal circuitry.
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Affiliation(s)
- Steve C Danzer
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
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Molinaro G, Battaglia G, Riozzi B, Storto M, Fucile S, Eusebi F, Nicoletti F, Bruno V. GABAergic drugs become neurotoxic in cortical neurons pre-exposed to brain-derived neurotrophic factor. Mol Cell Neurosci 2008; 37:312-22. [DOI: 10.1016/j.mcn.2007.10.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2007] [Revised: 10/12/2007] [Accepted: 10/16/2007] [Indexed: 11/27/2022] Open
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Kondziella D, Alvestad S, Vaaler A, Sonnewald U. Which clinical and experimental data link temporal lobe epilepsy with depression? J Neurochem 2007; 103:2136-52. [PMID: 17887964 DOI: 10.1111/j.1471-4159.2007.04926.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The association of temporal lobe epilepsy with depression and other neuropsychiatric disorders has been known since the early beginnings of neurology and psychiatry. However, only recently have in vivo and ex vivo techniques such as Positron Emission Tomography, Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy in combination with refined animal models and behavioral tests made it possible to identify an emerging pattern of common pathophysiological mechanisms. We now have growing evidence that in both disorders altered interaction of serotonergic and noradrenergic neurons with glutamatergic systems is associated with abnormal neuronal circuits and hyperexcitability. Neuronal hyperexcitability can possibly evoke seizure activity as well as disturbed emotions. Moreover, decreased synaptic levels of neurotransmitters and high glucocorticoid levels influence intracellular signaling pathways such as cAMP, causing disturbances of brain-derived and other neurotrophic factors. These may be associated with hippocampal atrophy seen on Magnetic Resonance Imaging and memory impairment as well as altered fear processing and transient hypertrophy of the amygdala. Positron Emission Tomography studies additionally suggest hypometabolism of glucose in temporal and frontal lobes. Last, but not least, in temporal lobe epilepsy and depression astrocytes play a role that reaches far beyond their involvement in hippocampal sclerosis and ultimately, therapeutic regulation of glial-neuronal interactions may be a target for future research. All these mechanisms are strongly intertwined and probably bidirectional such that the structural and functional alterations from one disease increase the risk for developing the other. This review provides an integrative update of the most relevant experimental and clinical data on temporal lobe epilepsy and its association with depression.
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Affiliation(s)
- Daniel Kondziella
- Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway.
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Deller T, Haas CA, Freiman TM, Phinney A, Jucker M, Frotscher M. Lesion-Induced Axonal Sprouting in the Central Nervous System. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 557:101-21. [PMID: 16955706 DOI: 10.1007/0-387-30128-3_6] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Injury or neuronal death often come about as a result of brain disorders. Inasmuch as the damaged nerve cells are interconnected via projections to other regions of the brain, such lesions lead to axonal loss in distal target areas. The central nervous system responds to deafferentation by means of plastic remodeling processes, in particular by inducing outgrowth of new axon collaterals from surviving neurons (collateral sprouting). These sprouting processes result in a partial reinnervation, new circuitry, and functional changes within the deafferented brain regions. Lesioning of the entorhinal cortex is an established model system for studying the phenomenon of axonal sprouting. Using this model system, it could be shown that the sprouting process respects the pre-existing lamination pattern of the deafferented fascia dentata, i. e., it is layer-specific. A variety of different molecules are involved in regulating this reorganization process (extracellular matrix molecules, cell adhesion molecules, transcription factors, neurotrophic factors, growth-associated proteins). It is proposed here that molecules of the extracellular matrix define the boundaries of the laminae following entorhinal lesioning and in so doing limit the sprouting process to the deafferented zone. To illustrate the role of axonal sprouting in disease processes, special attention is given to its significance for neurodegenerative disorders, particularly Alzheimer's disease (AD), and temporal lobe epilepsy. Finally, we discuss both the beneficial as well as disadvantageous functional implications of axonal sprouting for the injured organism in question.
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Affiliation(s)
- Thomas Deller
- Institute of Clinical Neuroanatomy, Johann Wolfgang Goether-University, Frankfurt am Main, Germany
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37
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Tóth K, Wittner L, Urbán Z, Doyle WK, Buzsáki G, Shigemoto R, Freund TF, Maglóczky Z. Morphology and synaptic input of substance P receptor-immunoreactive interneurons in control and epileptic human hippocampus. Neuroscience 2007; 144:495-508. [PMID: 17097238 PMCID: PMC2753206 DOI: 10.1016/j.neuroscience.2006.09.039] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Revised: 09/22/2006] [Accepted: 09/22/2006] [Indexed: 01/08/2023]
Abstract
Substance P (SP) is known to be a peptide that facilitates epileptic activity of principal cells in the hippocampus. Paradoxically, in other models, it was found to be protective against seizures by activating substance P receptor (SPR)-expressing interneurons. Thus, these cells appear to play an important role in the generation and regulation of epileptic seizures. The number, distribution, morphological features and input characteristics of SPR-immunoreactive cells were analyzed in surgically removed hippocampi of 28 temporal lobe epileptic patients and eight control hippocampi in order to examine their changes in epileptic tissues. SPR is expressed in a subset of inhibitory cells in the control human hippocampus, they are multipolar interneurons with smooth dendrites, present in all hippocampal subfields. This cell population is considerably different from SPR-positive cells of the rat hippocampus. The CA1 (cornu Ammonis subfield 1) region was chosen for the detailed morphological analysis of the SPR-immunoreactive cells because of its extreme vulnerability in epilepsy. The presence of various neurochemical markers identifies functionally distinct interneuron types, such as those responsible for perisomatic, dendritic or interneuron-selective inhibition. We found considerable colocalization of SPR with calbindin but not with parvalbumin, calretinin, cholecystokinin and somatostatin, therefore we suppose that SPR-positive cells participate mainly in dendritic inhibition. In the non-sclerotic CA1 region they are mainly preserved, whereas their number is decreased in the sclerotic cases. In the epileptic samples their morphology is considerably altered, they possessed more dendritic branches, which often became beaded. Analyses of synaptic coverage revealed that the ratio of symmetric synaptic input of SPR-immunoreactive cells has increased in epileptic samples. Our results suggest that SPR-positive cells are preserved while principal cells are present in the CA1 region, but show reactive changes in epilepsy including intense branching and growth of their dendritic arborization.
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Affiliation(s)
- Kinga Tóth
- Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1450, Budapest, Hungary
| | - Lucia Wittner
- Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1450, Budapest, Hungary
| | - Zoltán Urbán
- Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1450, Budapest, Hungary
| | - Werner K. Doyle
- Department of Neurosurgery, New York University, School of Medicine, New York, NY 10016, USA
| | - György Buzsáki
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ 07102, USA
| | - Ryuichi Shigemoto
- Division of Cerebral Structure, National Institute for Physiological Sciences, Myodaiji, Okazaki 444-8585, Japan
| | - Tamás F. Freund
- Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1450, Budapest, Hungary
| | - Zsófia Maglóczky
- Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1450, Budapest, Hungary
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Abstract
Since the discovery of nerve growth factor (NGF) in the 1950s and brain-derived neurotrophic factor (BDNF) in the 1980s, a great deal of evidence has mounted for the roles of neurotrophins (NGF; BDNF; neurotrophin-3, NT-3; and neurotrophin-4/5, NT-4/5) in development, physiology, and pathology. BDNF in particular has important roles in neural development and cell survival, as well as appearing essential to molecular mechanisms of synaptic plasticity and larger scale structural rearrangements of axons and dendrites. Basic activity-related changes in the central nervous system (CNS) are thought to depend on BDNF modulation of synaptic transmission. Pathologic levels of BDNF-dependent synaptic plasticity may contribute to conditions such as epilepsy and chronic pain sensitization, whereas application of the trophic properties of BDNF may lead to novel therapeutic options in neurodegenerative diseases and perhaps even in neuropsychiatric disorders. In this chapter, I review neurotrophin structure, signal transduction mechanisms, localization and regulation within the nervous system, and various potential roles in disease. Modulation of neurotrophin action holds significant potential for novel therapies for a variety of neurological and psychiatric disorders.
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Affiliation(s)
- Devin K Binder
- Department of Neurological Surgery, University of California, Irvine, CA 92868, USA.
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Simonato M, Tongiorgi E, Kokaia M. Angels and demons: neurotrophic factors and epilepsy. Trends Pharmacol Sci 2006; 27:631-8. [PMID: 17055067 DOI: 10.1016/j.tips.2006.10.002] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2006] [Revised: 09/11/2006] [Accepted: 10/09/2006] [Indexed: 12/29/2022]
Abstract
Several lines of evidence indicate that neurotrophic factors (NTFs) could be key causal mediators in the development of acquired epileptic syndromes. Yet the trophic properties of NTFs indicate that they might be used to treat epilepsy-associated damage. Accordingly, different NTFs, or even the same NTF, could produce functionally contrasting effects in the context of epilepsy. Recent experimental evidence begins to shed light on the mechanisms underlying these contrasting effects. Understanding these mechanisms will be instrumental for the development of effective therapies, which must be based on a careful consideration of the biological properties of NTFs. Here, we critically evaluate new information emerging in this area and discuss its implications for clinical treatment.
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Affiliation(s)
- Michele Simonato
- Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Ferrara, Ferrara 44100, Italy.
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Zhang HT, Li LY, Zou XL, Song XB, Hu YL, Feng ZT, Wang TTH. Immunohistochemical distribution of NGF, BDNF, NT-3, and NT-4 in adult rhesus monkey brains. J Histochem Cytochem 2006; 55:1-19. [PMID: 16899765 DOI: 10.1369/jhc.6a6952.2006] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Immunohistochemical distribution and cellular localization of neurotrophins was investigated in adult monkey brains using antisera against nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4 (NT-4). Western blot analysis showed that each antibody specifically recognized appropriate bands of approximately 14.7 kDa, 14.2 kDa, 13.6 kDa, and 14.5 kDa, for NGF, BDNF, NT-3, and NT-4, respectively. These positions coincided with the molecular masses of the neurotrophins studied. Furthermore, sections exposed to primary antiserum preadsorbed with full-length NGF, BDNF, NT-3, and NT-4 exhibited no detectable immunoreactivity, demonstrating specificities of the antibodies against the tissues prepared from rhesus monkeys. The study provided a systematic report on the distribution of NGF, BDNF, NT-3, and NT-4 in the monkey brain. Varying intensity of immunostaining was observed in the somata and processes of a wide variety of neurons and glial cells in the cerebrum, cerebellum, hippocampus, and other regions of the brain. Neurons in some regions such as the cerebral cortex and the hippocampus, which stained for neurotrophins, also expressed neurotrophic factor mRNA. In some other brain regions, there was discrepancy of protein distribution and mRNA expression reported previously, indicating a retrograde or anterograde action mode of neurotrophins. Results of this study provide a morphological basis for the elucidation of the roles of NGF, BDNF, NT-3, and NT-4 in adult primate brains.
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Affiliation(s)
- Hong-Tian Zhang
- Institute for Research on Neuroscience, Kunming Medical College, Kunming, China
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41
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Csaba Z, Pirker S, Lelouvier B, Simon A, Videau C, Epelbaum J, Czech T, Baumgartner C, Sperk G, Dournaud P. Somatostatin receptor type 2 undergoes plastic changes in the human epileptic dentate gyrus. J Neuropathol Exp Neurol 2005; 64:956-69. [PMID: 16254490 DOI: 10.1097/01.jnen.0000186923.50215.50] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Temporal lobe epilepsy (TLE) is characterized by hippocampal sclerosis together with profound losses and phenotypic changes of different classes of interneurons, including those expressing somatostatin (SRIF). To understand the functional significance of the plasticity of SRIF transmission in TLE, unraveling the status of SRIF receptors is, however, a prerequisite. To address this issue, we characterized expression and distribution of the major SRIF receptor, the sst2 subtype, in hippocampal tissue resected in patients with TLE using complementary neuroanatomic approaches. In patients with hippocampal sclerosis, the number of cells expressing sst2 receptor mRNA as well as sst2 receptor-binding sites and immunoreactivity decreased significantly in the CA1-3, reflecting neuronal loss. By contrast, in the dentate gyrus, sst2 receptor mRNA expression was strongly increased in the granule cell layer, and sst2 receptor-binding sites and immunoreactivity was preserved in the inner but decreased significantly in the outer molecular layer. In this latter region, pronounced changes in SRIF terminal fields were observed. Decreased receptor density in the distal dendrites of granule cells is likely to reflect downregulation of sst2 receptors in response to physiopathologic release of SRIF. Because sst2 receptors have anticonvulsant and antiepileptogenic properties, this phenomenon may contribute to the etiology of TLE seizures.
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Affiliation(s)
- Zsolt Csaba
- Neuroendocrine Research Laboratory, Hungarian Academy of Sciences and Department of Human Morphology and Developmental Biology, Semmelweis University, Budapest
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42
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Abstract
Our understanding of the pathogenesis of the neuropathology of epilepsy has been challenged by a need to separate the "lesions" that cause epilepsy from the "lesions" that are produced by the epilepsy. Significant clinical, genetic, pathologic, and experimental studies of Ammon horn sclerosis (AHS) suggest that AHS is the result and cause of seizures. The data support the idea that seizures cause alterations in cell numbers, cell shape, and organization of neuronal circuitry, thus setting up an identifiable seizure-genic focus. As such, AHS represents a slowly progressive lesion and a search for the cause of the initiating seizure has led to the identification of ion channel mutations. In this report, the neuropathology of other conditions associated with intractable epilepsy is considered, suggesting that in them similar epilepsy-produced alterations in microarchitecture can be observed. The idea is important to define the optimum time for epilepsy surgery and the underlying etiology of these seizure-genic lesions.
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Affiliation(s)
- Dawna Duncan Armstrong
- Department of Pathology, Texas Children's Hospital & Baylor College of Medicine, 6621 Fannin Street, Houston, TX 77030, USA.
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Hagihara H, Hara M, Tsunekawa K, Nakagawa Y, Sawada M, Nakano K. Tonic–clonic seizures induce division of neuronal progenitor cells with concomitant changes in expression of neurotrophic factors in the brain of pilocarpine–treated mice. ACTA ACUST UNITED AC 2005; 139:258-66. [PMID: 16023256 DOI: 10.1016/j.molbrainres.2005.05.031] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2004] [Revised: 05/16/2005] [Accepted: 05/24/2005] [Indexed: 11/19/2022]
Abstract
Epileptic seizures cause severe and long-lasting events on the architecture of the brain, including neuronal cell death, accompanied neurogenesis, reactive gliosis, and mossy fiber sprouting. However, it remains uncertain whether these functional and anatomical alterations are associated with the development of hyperexcitability, or as inhibitory processes. Neurotrophic factors are probable mediators of these pathophysiological events. The present study was designed to clarify the role of various neurotrophic factors on the pilocarpine model of seizures. At 4 h following pilocarpine-induced seizures, expression of NGF, BDNF, HB-EGF, and FGF-2 increased only in the mice manifesting tonic-clonic convulsions and not in mice without seizures. NT-3 expression decreased in pilocarpine-treated mice experiencing seizures, tonic-clonic or not, compared to mice with no seizures. Neuronal cell damage, which was evident by Fluoro-Jade B staining, was observed within 24 h in the mice exhibiting tonic-clonic seizures, followed by an increase in the number of BrdU-positive cells and glial cells, which were evident after 2 days. None of these pathophysiological changes occurred in the mice which showed no seizures, although they were injected with pilocarpine, nor in the activated epilepsy-prone EL mice, which experienced repeated severe seizures. Together, these results suggest that neuronal damage occurring in the brain of the mice manifesting tonic-clonic seizures is accompanied by neurogenesis. This sequence of events may be regulated through changes in expression of neurotrophic factors such as NGF, BDNF, HB-FGF, and NT-3.
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Affiliation(s)
- Hideo Hagihara
- Nagoya University Bioscience and Biotechnology Center, Chikusa, Nagoya 464-8601, Japan
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Shapiro LA, Ribak CE. Integration of newly born dentate granule cells into adult brains: hypotheses based on normal and epileptic rodents. ACTA ACUST UNITED AC 2005; 48:43-56. [PMID: 15708627 DOI: 10.1016/j.brainresrev.2004.08.003] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2004] [Indexed: 11/17/2022]
Abstract
The granule cells of the dentate gyrus are a population of neurons continuously generated throughout life. In the rat, the morphological development of newly born granule cells generated in the adult share many similarities with granule cells generated during development. These include a specific migration pattern, orientation and progression of neurite outgrowth. It appears as though varied dendritic morphology occurs depending on the position of the granule cells within the granule cell layer. A hypothesis for granule cell migration and differentiation of their dendritic processes is proposed based on normal and epileptic rats. In this hypothesis, the granule cells are generated in the subgranular zone, and then they migrate into the granule cell layer. During this migration, the sequence of neurite outgrowth is described, where the newly born granule cell first sprouts rudimentary processes. One of these processes, the basal dendrite, is transiently present on developing rodent granule cells in rats. However, in seizure-induced rats the basal dendrite often fails to retract, which leads to the formation of hilar basal dendrites, and also perhaps, ectopic granule cells in the hilus. In this review, granule cell development is discussed with relevance to the creation of the recurrent excitatory circuitry in rodent models of temporal lobe epilepsy.
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Affiliation(s)
- Lee A Shapiro
- Department of Anatomy and Neurobiology, College of Medicine, University of California, Irvine, Irvine, CA 92697, USA
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45
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Abstract
Since the purification of BDNF in 1982, a great deal of evidence has mounted for its central roles in brain development, physiology, and pathology. Aside from its importance in neural development and cell survival, BDNF appears essential to molecular mechanisms of synaptic plasticity. Basic activity-related changes in the central nervous system are thought to depend on BDNF modification of synaptic transmission, especially in the hippocampus and neocortex. Pathologic levels of BDNF-dependent synaptic plasticity may contribute to conditions such as epilepsy and chronic pain sensitization, whereas application of the trophic properties of BDNF may lead to novel therapeutic options in neurodegenerative diseases and perhaps even in neuropsychiatric disorders.
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Affiliation(s)
- Devin K Binder
- Department of Neurological Surgery, M779 Moffitt Hospital, Box 0112, University of California, San Francisco, CA 94143-0112, USA.
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46
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Ozbas-Gerçeker F, Gorter JA, Redeker S, Ramkema M, van der Valk P, Baayen JC, Ozgüç M, Saygi S, Soylemezoglu F, Akalin N, Troost D, Aronica E. Neurotrophin receptor immunoreactivity in the hippocampus of patients with mesial temporal lobe epilepsy. Neuropathol Appl Neurobiol 2004; 30:651-64. [PMID: 15541005 DOI: 10.1111/j.1365-2990.2004.00582.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recent evidence supports a critical role of neurotrophins in the regulation of both neuronal survival and synaptic transmission during epileptogenesis. We have examined the immunohistochemical expression of high- (tyrosine kinase receptors, trk) and low-affinity (p75) neurotrophin receptors (NTRs) in the hippocampal specimens from 18 patients with chronic temporal lobe epilepsy [TLE; 14 patients with hippocampal sclerosis (HS) and four with focal lesions (tumours) not involving the hippocampus proper]. Nonepileptic autopsy brains (n = 6) and surgical specimens from tumour patients without epilepsy (n = 3) were used as controls. Immunoreactivity (IR) for the trk receptors (trkA, trkB, trkC) was detected in normal human brain within the pyramidal neurones of hippocampal cornus ammoni (CA) regions and in the dentate gyrus. There were no detectable differences in the neuronal trk IR patterns in the hippocampus between control and TLE cases with HS, except for a decrease in neuronal density in regions where cell death had occurred (CA1, CA3 and CA4). In contrast, a consistent increase in trkA IR was observed in reactive astrocytes in CA1 and dentate gyrus. The low-affinity p75 neurotrophin receptor (p75(NTR)) was expressed in low levels in postnatal normal hippocampus. In contrast, neuronal p75(NTR) IR was detected in 10/14 cases of HS in spared neurones within the CA and hilar regions of the hippocampus. Double labelling revealed that p75(NTR)-positive neurones also contain trk receptor IR. In six cases with prominent glial activation strong p75(NTR) IR was observed in microglial cells within the sclerotic hippocampus. The present results indicate that changes in NTR expression are still detectable in the hippocampus of patients with chronic TLE and involve both glial and neuronal cells. Reactive astrocytes were immunoreactive for trkA, whereas activated microglia cells were reactive for p75(NTR), suggesting different functions for specific NTRs in the development of reactive gliosis. Moreover, the increased expression of p75(NTR) in hippocampal neurones of TLE patients may critically influence the neuronal survival during the epileptogenic process.
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Affiliation(s)
- F Ozbas-Gerçeker
- Department of Medical Biology, Hacettepe University, Ankara, Turkey
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Bandtlow CE, Dlaska M, Pirker S, Czech T, Baumgartner C, Sperk G. Increased expression of Nogo-A in hippocampal neurons of patients with temporal lobe epilepsy. Eur J Neurosci 2004; 20:195-206. [PMID: 15245492 DOI: 10.1111/j.1460-9568.2004.03470.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Mesial temporal lobe epilepsy (TLE) is associated with pronounced anatomical and biochemical changes in the hippocampal formation including extensive neurodegeneration, reorganization of mossy fibres and sprouting of interneurons. Although the anatomical features and some of the physiological consequences of hippocampal remodeling have been well documented, the molecular mechanisms underlying the profound and orientated outgrowth of hippocampal neurons in TLE are not yet understood. The reticulon protein Nogo-A has been associated with an inhibitory action on axon growth and plasticity. Using immunohistochemistry and in situ hybridization, we investigated the expression of Nogo-A in specimens obtained at surgery from patients with TLE compared with those obtained from autopsy controls. In control specimens, Nogo-A immunoreactivity and mRNA were mainly confined to oligodendrocytes. Only approximately 40% of the specimens revealed low expression of Nogo-A mRNA in neurons. In contrast, in TLE patients with and without Ammon's horn sclerosis, Nogo-A mRNA and immunoreactivity were markedly up-regulated in most neurons (3.6- and 4.4-fold increases in Nogo-A mRNA in granule cells of sclerotic and nonsclerotic specimens) and their processes throughout the hippocampal formation. Similar elevations in Nogo-A mRNA and protein levels were determined by quantitative RT-PCR and Western blotting. Since Nogo-A expression was also up-regulated in specimens without hippocampal sclerosis, it may be induced by seizures prior to progressing neurodegeneration.
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Affiliation(s)
- Christine E Bandtlow
- Institute of Medical Chemistry and Biochemistry, Medical University of Innsbruck, A-6020 Innsbruck, Austria.
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Seifert G, Hüttmann K, Schramm J, Steinhäuser C. Enhanced relative expression of glutamate receptor 1 flip AMPA receptor subunits in hippocampal astrocytes of epilepsy patients with Ammon's horn sclerosis. J Neurosci 2004; 24:1996-2003. [PMID: 14985442 PMCID: PMC6730392 DOI: 10.1523/jneurosci.3904-03.2004] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Astrocytes express ionotropic glutamate receptors (GluRs), and recent evidence suggests that these receptors contribute to direct signaling between neurons and glial cells in vivo. Here, we have used functional and molecular analyses to investigate receptor properties in astrocytes of human hippocampus resected from patients with pharmacoresistant temporal lobe epilepsy (TLE). Histopathological analysis allowed us to distinguish two forms of epilepsy: Ammon's horn sclerosis (AHS) and lesion-associated TLE. Human hippocampal astrocytes selectively expressed the AMPA subtype of ionotropic glutamate receptors. Single-cell RT-PCR found preferential expression of the subunits GluR1 and GluR2 in human astrocytes, and the expression patterns were similar in patients with AHS and lesion-associated epilepsy. The AMPA receptor-specific modulators, cyclothiazide (CTZ) and 4-[2-(phenylsulfonylamino)ethylthio]-2,6-difluoro-phenoxyacetamide (PEPA), were used to investigate splice variant expression. Astrocytes of sclerotic specimens displayed a slower dissociation of CTZ from the receptor and a lower ratio of current potentiation by PEPA to potentiation by CTZ, suggesting enhanced expression of flip receptor variants in AHS versus lesion-associated epilepsy. Real-time PCR and restriction analysis substantiated this presumption by identifying elevated flip-to-flop mRNA ratios of GluR1 in single astrocytes of AHS specimens. These findings imply that in AHS, glutamate may lead to prolonged depolarization of astrocytes, thereby facilitating the generation or spread of seizure activity.
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Affiliation(s)
- Gerald Seifert
- Experimental Neurobiology, Department of Neurosurgery, University of Bonn, 53105 Bonn, Germany.
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Mhyre TR, Applegate CD. Persistent regional increases in brain-derived neurotrophic factor in the flurothyl model of epileptogenesis are dependent upon the kindling status of the animal. Neuroscience 2004; 121:1031-45. [PMID: 14580953 DOI: 10.1016/s0306-4522(03)00475-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) appears to be both regulated by and a regulator of epileptogenesis. In the flurothyl (HFE) model of kindling mice exposed to successive flurothyl trials over 8 days express a rapid, long-lasting reduction in generalized seizure threshold and a more slowly evolving change in seizure phenotype in response to subsequent flurothyl exposure. The BDNF genotype of particular mouse strains appears to influence the epileptogenic progression in this model. Thus, we hypothesized that BDNF signaling pathways are altered by flurothyl-induced seizures. Following HFE kindling, fully kindled (eight seizures) adult male C57BI/6J mice had significantly elevated whole brain BDNF levels through at least 28 days after their final seizure. Mice that received only four HFE seizures (not kindled) had elevated BDNF levels, but only at 1 day post-seizure (DPSz), while BDNF levels were not significantly altered in mice receiving just one HFE seizure at any time point studied. Regional expression patterns of BDNF in the hippocampus, hypothalamus, and frontal cortex were also elevated by one DPSz and returned to control values by 14 DPSz in mice that received four HFE seizures. No changes were seen in the cerebellum, striatum, or piriform cortex. In contrast, fully kindled mice had significantly elevated BDNF levels within the hippocampus, hypothalamus, neocortex, and striatum that remained elevated through at least 14 DPSz, while levels were unchanged in the cerebellum and piriform cortex. Regional results were confirmed using anti-BDNF immunohistochemistry (IHC). Despite changes in BDNF levels following HFE kindling, we were unable to demonstrate alterations either in full-length tyrosine kinase receptor B (TrkB) expression (Western blot and IHC) or in truncated TrkB (IHC) expression levels. Together, these data suggest a model of a positive feedback loop involving seizure activity and seizure number and persistently modified BDNF signaling pathways that influences seizure phenotypes within the HFE kindling paradigm. Thus, long-term elevations in BDNF may be responsible in part for epileptogenic processes and the development of human refractory epilepsies.
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Affiliation(s)
- T R Mhyre
- Strong Epilepsy Center, Department of Neurology, University of Rochester Medical Center, Box 673, 601 Elmwood Avenue, Rochester, NY 14642, USA.
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Binder DK. The Role of BDNF in Epilepsy and Other Diseases of the Mature Nervous System. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2004; 548:34-56. [PMID: 15250584 DOI: 10.1007/978-1-4757-6376-8_3] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The neurotrophin brain-derived neurotrophic factor (BDNF) is ubiquitous in the central nervous system (CNS) throughout life. In addition to trophic effects on target neurons, BDNF appears to be part of a general mechanism for activity-dependent modification of synapses in the developing and adult nervous system. Thus, diseases of abnormal trophic support (such as neurodegenerative diseases) and diseases of abnormal excitability (such as epilepsy and central pain sensitization) can be related in some cases to abnormal BDNF signaling. For example, various studies have shown that BDNF is upregulated in areas implicated in epileptogenesis, and interference with BDNF signal transduction inhibits the development of the epileptic state. Further study of the cellular and molecular mechanisms by which BDNF influences cell survival and excitability will likely provide novel concepts and targets for the treatment of diverse CNS diseases.
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Affiliation(s)
- Devin K Binder
- Department of Neurological Surgery, University of California at San Francisco, Moffitt Hospital, USA
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