51
|
Shiha AA, de Cristóbal J, Delgado M, Fernández de la Rosa R, Bascuñana P, Pozo MA, García-García L. Subacute administration of fluoxetine prevents short-term brain hypometabolism and reduces brain damage markers induced by the lithium-pilocarpine model of epilepsy in rats. Brain Res Bull 2015; 111:36-47. [DOI: 10.1016/j.brainresbull.2014.12.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 12/12/2014] [Accepted: 12/16/2014] [Indexed: 12/30/2022]
|
52
|
Role of TGF-β signaling pathway on Tenascin C protein upregulation in a pilocarpine seizure model. Epilepsy Res 2014; 108:1694-704. [PMID: 25445237 DOI: 10.1016/j.eplepsyres.2014.09.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Revised: 08/29/2014] [Accepted: 09/21/2014] [Indexed: 02/03/2023]
Abstract
Seizures have been shown to upregulate the expression of numerous extracellular matrix molecules. Tenascin C (TNC) is an extracellular matrix protein involved in several physiological roles and in pathological conditions. Though TNC upregulation has been described after excitotoxins injection, to date there is no research work on the signal transduction pathway(s) participating in TNC protein overproduction. The aim of this study was to evaluate the role of TGF-β signaling pathway on TNC upregulation. In this study, we used male rats, which were injected with saline or pilocarpine to induce status epilepticus (SE) and killed 24h, 3 and 7 days after pilocarpine administration. For evaluating biochemical changes, we measured protein content of TNC, TGF-β1 and phospho-Smad2/3 for localization of TNC in coronal brain hippocampus at 24h, 3 and 7 days after pilocarpine-caused SE. We found a significant increase of TNC protein content in hippocampal homogenates after 1, 3, and 7 days of pilocarpine-caused SE, together with an enhancement of TNC immunoreactivity in several hippocampal layers and the dentate gyrus field where more dramatic changes occurred. We also observed a significant enhancement of protein content of both the TGF-β1 and the critical downstream transduction effector phospho-Smad2/3 throughout the chronic exposure. Interestingly, animals injected with SB-431542, a TGF-β-type I receptor inhibitor, decreased TNC content in cytosolic fraction and diminished phospho-Smad2/3 content in both cytoplasmic and nuclear fraction compared with pilocarpine vehicle-injected. These findings suggest the participation of TGF-β signaling pathway on upregulation of TNC which in turn support the idea that misregulation of this signaling pathway produces changes that may contribute to disease.
Collapse
|
53
|
Yamawaki R, Thind K, Buckmaster PS. Blockade of excitatory synaptogenesis with proximal dendrites of dentate granule cells following rapamycin treatment in a mouse model of temporal lobe epilepsy. J Comp Neurol 2014; 523:281-97. [PMID: 25234294 DOI: 10.1002/cne.23681] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 09/09/2014] [Accepted: 09/16/2014] [Indexed: 12/13/2022]
Abstract
Inhibiting the mammalian target of rapamycin (mTOR) signaling pathway with rapamycin blocks granule cell axon (mossy fiber) sprouting after epileptogenic injuries, including pilocarpine-induced status epilepticus. However, it remains unclear whether axons from other types of neurons sprout into the inner molecular layer and synapse with granule cell dendrites despite rapamycin treatment. If so, other aberrant positive-feedback networks might develop. To test this possibility stereological electron microscopy was used to estimate the numbers of excitatory synapses in the inner molecular layer per hippocampus in pilocarpine-treated control mice, in mice 5 days after pilocarpine-induced status epilepticus, and after status epilepticus and daily treatment beginning 24 hours later with rapamycin or vehicle for 2 months. The optical fractionator method was used to estimate numbers of granule cells in Nissl-stained sections so that numbers of excitatory synapses in the inner molecular layer per granule cell could be calculated. Control mice had an average of 2,280 asymmetric synapses in the inner molecular layer per granule cell, which was reduced to 63% of controls 5 days after status epilepticus, recovered to 93% of controls in vehicle-treated mice 2 months after status epilepticus, but remained at only 63% of controls in rapamycin-treated mice. These findings reveal that rapamycin prevented excitatory axons from synapsing with proximal dendrites of granule cells and raise questions about the recurrent excitation hypothesis of temporal lobe epilepsy.
Collapse
Affiliation(s)
- Ruth Yamawaki
- Department of Comparative Medicine, Stanford University, Stanford, CA, 94305
| | | | | |
Collapse
|
54
|
Jie L, Guohui J, Chen Y, Chen L, Li Z, Wang Z, Wang X. Altered expression of hypoxia-Inducible factor-1α participates in the epileptogenesis in animal models. Synapse 2014; 68:402-9. [PMID: 24889205 DOI: 10.1002/syn.21752] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 05/22/2014] [Accepted: 05/23/2014] [Indexed: 12/23/2022]
Affiliation(s)
- Li Jie
- Department of Neurology; The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology; Chongqing 400016 China
| | - Jiang Guohui
- Department of Neurology; Affiliated Hospital of Chuanbei Medical College; Nanchong 637000 Sichuan Province China
| | - Yalan Chen
- Department of Neurology; The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology; Chongqing 400016 China
| | - Ling Chen
- Department of Neurology; The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology; Chongqing 400016 China
| | - Zengyou Li
- Department of Neurology; The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology; Chongqing 400016 China
| | - Zhihua Wang
- Department of Neurology; The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology; Chongqing 400016 China
| | - Xuefeng Wang
- Department of Neurology; The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology; Chongqing 400016 China
| |
Collapse
|
55
|
Expression of Nampt in hippocampal and cortical excitatory neurons is critical for cognitive function. J Neurosci 2014; 34:5800-15. [PMID: 24760840 DOI: 10.1523/jneurosci.4730-13.2014] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Nicotinamide adenine dinucleotide (NAD(+)) is an enzyme cofactor or cosubstrate in many essential biological pathways. To date, the primary source of neuronal NAD(+) has been unclear. NAD(+) can be synthesized from several different precursors, among which nicotinamide is the substrate predominantly used in mammals. The rate-limiting step in the NAD(+) biosynthetic pathway from nicotinamide is performed by nicotinamide phosphoribosyltransferase (Nampt). Here, we tested the hypothesis that neurons use intracellular Nampt-mediated NAD(+) biosynthesis by generating and evaluating mice lacking Nampt in forebrain excitatory neurons (CaMKIIαNampt(-/-) mice). CaMKIIαNampt(-/-) mice showed hippocampal and cortical atrophy, astrogliosis, microgliosis, and abnormal CA1 dendritic morphology by 2-3 months of age. Importantly, these histological changes occurred with altered intrahippocampal connectivity and abnormal behavior; including hyperactivity, some defects in motor skills, memory impairment, and reduced anxiety, but in the absence of impaired sensory processes or long-term potentiation of the Schaffer collateral pathway. These results clearly demonstrate that forebrain excitatory neurons mainly use intracellular Nampt-mediated NAD(+) biosynthesis to mediate their survival and function. Studying this particular NAD(+) biosynthetic pathway in these neurons provides critical insight into their vulnerability to pathophysiological stimuli and the development of therapeutic and preventive interventions for their preservation.
Collapse
|
56
|
Woeffler-Maucler C, Beghin A, Ressnikoff D, Bezin L, Marinesco S. Automated immunohistochemical method to quantify neuronal density in brain sections: application to neuronal loss after status epilepticus. J Neurosci Methods 2014; 225:32-41. [PMID: 24462622 DOI: 10.1016/j.jneumeth.2014.01.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 01/10/2014] [Accepted: 01/13/2014] [Indexed: 12/28/2022]
Abstract
BACKGROUND To study neurotoxic processes, it is necessary to quantify the number of neurons in a given brain structure and estimate neuronal loss. Neuronal densities can be estimated by immunohistochemical quantitation of a neuronal marker such as the protein NeuN. However, NeuN expression may vary, depending on certain pathophysiological conditions and bias such quantifications. NEW METHOD We have developed a simple automatic quantification of neuronal densities in brain sections stained with DAPI and antibody to NeuN. This method determines the number of DAPI-positive nuclei also positive for NeuN in at least two adjacent sections within a Z-stack of optical sections. RESULTS We tested this method in animals with induced status epilepticus (SE) a state of intractable persistent seizure that produces extensive neuronal injury. We found that SE significantly reduced neuronal density in the piriform cortex, the amygdala, the dorsal thalamus, the CA3 area of the hippocampus, the dentate gyrus and the hilus, but not in the somatosensory cortex or the CA1 area. SE resulted in increases in the total density of cellular nuclei within these brain structures, suggesting gliosis. COMPARISON WITH EXISTING METHODS This automated method was more accurate than simply estimating the overall NeuN fluorescence intensity in the brain section, and as accurate, but less time-consuming, than manual cell counts. CONCLUSION This method simplifies and accelerates the unbiased quantification of neuronal density. It can be easily applied to other models of brain injury and neurodegeneration, or used to screen the efficacy of neuroprotective treatments.
Collapse
Affiliation(s)
- Caroline Woeffler-Maucler
- Université de Lyon, Lyon, France; INSERM, Institut National de la Santé et de la Recherche Médicale, U1028, Lyon Neuroscience Research Center, Lyon, France; CNRS, Centre National de la Recherche Scientifique, UMR5292, Lyon Neuroscience Research Center, Lyon, France
| | - Anne Beghin
- Université de Lyon, Lyon, France; Centre Commun de Quantimétrie, Lyon F-69008, France
| | - Denis Ressnikoff
- Université de Lyon, Lyon, France; Centre Commun de Quantimétrie, Lyon F-69008, France
| | - Laurent Bezin
- Université de Lyon, Lyon, France; INSERM, Institut National de la Santé et de la Recherche Médicale, U1028, Lyon Neuroscience Research Center, Lyon, France; CNRS, Centre National de la Recherche Scientifique, UMR5292, Lyon Neuroscience Research Center, Lyon, France; IDÉE, Institut Des ÉpilepsiEs, Lyon, France
| | - Stéphane Marinesco
- Université de Lyon, Lyon, France; INSERM, Institut National de la Santé et de la Recherche Médicale, U1028, Lyon Neuroscience Research Center, Lyon, France; CNRS, Centre National de la Recherche Scientifique, UMR5292, Lyon Neuroscience Research Center, Lyon, France; Plate-forme technologique AniRA-Neurochem, Lyon F-69000, France.
| |
Collapse
|
57
|
Cho H, Sajja V, VandeVord P, Lee Y. Blast induces oxidative stress, inflammation, neuronal loss and subsequent short-term memory impairment in rats. Neuroscience 2013; 253:9-20. [DOI: 10.1016/j.neuroscience.2013.08.037] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 08/06/2013] [Accepted: 08/21/2013] [Indexed: 12/17/2022]
|
58
|
Gibbons M, Smeal R, Takahashi D, Vargas J, Wilcox K. Contributions of astrocytes to epileptogenesis following status epilepticus: opportunities for preventive therapy? Neurochem Int 2013; 63:660-9. [PMID: 23266599 PMCID: PMC4353644 DOI: 10.1016/j.neuint.2012.12.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 12/09/2012] [Accepted: 12/13/2012] [Indexed: 12/22/2022]
Abstract
Status epilepticus (SE) is a life threatening condition that often precedes the development of epilepsy. Traditional treatments for epilepsy have been focused on targeting neuronal mechanisms contributing to hyperexcitability, however, approximately 30% of patients with epilepsy do not respond to existing neurocentric pharmacotherapies. A growing body of evidence has demonstrated that profound changes in the morphology and function of astrocytes accompany SE and persist in epilepsy. Astrocytes are increasingly recognized for their diverse roles in modulating neuronal activity, and understanding the changes in astrocytes following SE could provide important clues about the mechanisms underlying seizure generation and termination. By understanding the contributions of astrocytes to the network changes underlying epileptogenesis and the development of epilepsy, we will gain a greater appreciation of the contributions of astrocytes to dynamic circuit changes, which will enable us to develop more successful therapies to prevent and treat epilepsy. This review summarizes changes in astrocytes following SE in animal models and human temporal lobe epilepsy and addresses the functional consequences of those changes that may provide clues to the process of epileptogenesis.
Collapse
Affiliation(s)
- M.B. Gibbons
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT
| | - R.M. Smeal
- Department of Pharmacology & Toxicology, University of Utah, Salt Lake City, UT
| | - D.K. Takahashi
- Department of Neurology, Stanford University, Palo Alto, CA
| | - J.R. Vargas
- Department of Neurology, University of Utah, Salt Lake City, UT
| | - K.S. Wilcox
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT
- Department of Pharmacology & Toxicology, University of Utah, Salt Lake City, UT
| |
Collapse
|
59
|
Rossi AR, Angelo MF, Villarreal A, Lukin J, Ramos AJ. Gabapentin administration reduces reactive gliosis and neurodegeneration after pilocarpine-induced status epilepticus. PLoS One 2013; 8:e78516. [PMID: 24250797 PMCID: PMC3826740 DOI: 10.1371/journal.pone.0078516] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Accepted: 09/18/2013] [Indexed: 01/22/2023] Open
Abstract
The lithium-pilocarpine model of epilepsy reproduces in rodents several features of human temporal lobe epilepsy, by inducing an acute status epilepticus (SE) followed by a latency period. It has been proposed that the neuronal network reorganization that occurs during latency determines the subsequent appearance of spontaneous recurrent seizures. The aim of this study was to evaluate neuronal and glial responses during the latency period that follows SE. Given the potential role of astrocytes in the post-SE network reorganization, through the secretion of synaptogenic molecules such as thrombospondins, we also studied the effect of treatment with the α2δ1 thrombospondin receptor antagonist gabapentin. Adult male Wistar rats received 3 mEq/kg LiCl, and 20 h later 30 mg/kg pilocarpine. Once SE was achieved, seizures were stopped with 20 mg/kg diazepam. Animals then received 400 mg/kg/day gabapentin or saline for either 4 or 14 days. In vitro experiments were performed in dissociated mixed hippocampal cell culture exposed to glutamate, and subsequently treated with gabapentin or vehicle. During the latency period, the hippocampus and pyriform cortex of SE-animals presented a profuse reactive astrogliosis, with increased GFAP and nestin expression. Gliosis intensity was dependent on the Racine stage attained by the animals and peaked 15 days after SE. Microglia was also reactive after SE, and followed the same pattern. Neuronal degeneration was present in SE-animals, and also depended on the Racine stage and the SE duration. Polysialic-acid NCAM (PSA-NCAM) expression was increased in hippocampal CA-1 and dentate gyrus of SE-animals. Gabapentin treatment was able to reduce reactive gliosis, decrease neuronal loss and normalize PSA-NCAM staining in hippocampal CA-1. In vitro, gabapentin treatment partially prevented the dendritic loss and reactive gliosis caused by glutamate excitotoxicity. Our results show that gabapentin treatment during the latency period after SE protects neurons and normalizes PSA-NCAM probably by direct interaction with neurons and glia.
Collapse
Affiliation(s)
- Alicia Raquel Rossi
- Instituto de Biología Celular y Neurociencia “Prof. E. De Robertis”, Facultad de Medicina, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Maria Florencia Angelo
- Instituto de Biología Celular y Neurociencia “Prof. E. De Robertis”, Facultad de Medicina, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Alejandro Villarreal
- Instituto de Biología Celular y Neurociencia “Prof. E. De Robertis”, Facultad de Medicina, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Jerónimo Lukin
- Instituto de Biología Celular y Neurociencia “Prof. E. De Robertis”, Facultad de Medicina, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Alberto Javier Ramos
- Instituto de Biología Celular y Neurociencia “Prof. E. De Robertis”, Facultad de Medicina, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
- * E-mail:
| |
Collapse
|
60
|
Mazzuferi M, Kumar G, van Eyll J, Danis B, Foerch P, Kaminski RM. Nrf2 defense pathway: Experimental evidence for its protective role in epilepsy. Ann Neurol 2013; 74:560-8. [DOI: 10.1002/ana.23940] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 03/27/2013] [Accepted: 05/10/2013] [Indexed: 12/12/2022]
|