1
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Ohno M. A Strategy for Allowing Earlier Diagnosis and Rigorous Evaluation of BACE1 Inhibitors in Preclinical Alzheimer's Disease. J Alzheimers Dis 2024; 99:431-445. [PMID: 38701146 DOI: 10.3233/jad-231451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
Given continued failure of BACE1 inhibitor programs at symptomatic and prodromal stages of Alzheimer's disease (AD), clinical trials need to target the earlier preclinical stage. However, trial design is complex in this population with negative diagnosis of classical hippocampal amnesia on standard memory tests. Besides recent advances in brain imaging, electroencephalogram, and fluid-based biomarkers, new cognitive markers should be established for earlier diagnosis that can optimize recruitment to BACE1 inhibitor trials in presymptomatic AD. Notably, accelerated long-term forgetting (ALF) is emerging as a sensitive cognitive measure that can discriminate between asymptomatic individuals with high risks for developing AD and healthy controls. ALF is a form of declarative memory impairment characterized by increased forgetting rates over longer delays (days to months) despite normal storage within the standard delays of testing (20-60 min). Therefore, ALF may represent a harbinger of preclinical dementia and the impairment of systems memory consolidation, during which memory traces temporarily stored in the hippocampus become gradually integrated into cortical networks. This review provides an overview of the utility of ALF in a rational design of next-generation BACE1 inhibitor trials in preclinical AD. I explore potential mechanisms underlying ALF and relevant early-stage biomarkers useful for BACE1 inhibitor evaluation, including synaptic protein alterations, astrocytic dysregulation and neuron hyperactivity in the hippocampal-cortical network. Furthermore, given the physiological role of the isoform BACE2 as an AD-suppressor gene, I also discuss the possible association between the poor selectivity of BACE1 inhibitors and their side effects (e.g., cognitive worsening) in prior clinical trials.
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Affiliation(s)
- Masuo Ohno
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, USA
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2
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Keever KM, Li Y, Womble PD, Sullens DG, Otazu GH, Lugo JN, Ramos RL. Neocortical and cerebellar malformations affect flurothyl-induced seizures in female C57BL/6J mice. Front Neurosci 2023; 17:1271744. [PMID: 38027492 PMCID: PMC10651747 DOI: 10.3389/fnins.2023.1271744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 10/03/2023] [Indexed: 12/01/2023] Open
Abstract
Brain malformations cause cognitive disability and seizures in both human and animal models. Highly laminated structures such as the neocortex and cerebellum are vulnerable to malformation, affecting lamination and neuronal connectivity as well as causing heterotopia. The objective of the present study was to determine if sporadic neocortical and/or cerebellar malformations in C57BL/6J mice are correlated with reduced seizure threshold. The inhaled chemi-convulsant flurothyl was used to induce generalized, tonic-clonic seizures in male and female C57BL/6J mice, and the time to seizure onset was recorded as a functional correlate of brain excitability changes. Following seizures, mice were euthanized, and brains were extracted for histology. Cryosections of the neocortex and cerebellar vermis were stained and examined for the presence of molecular layer heterotopia as previously described in C57BL/6J mice. Over 60% of mice had neocortical and/or cerebellar heterotopia. No sex differences were observed in the prevalence of malformations. Significantly reduced seizure onset time was observed dependent on sex and the type of malformation present. These results raise important questions regarding the presence of malformations in C57BL/6J mice used in the study of brain development, epilepsy, and many other diseases of the nervous system.
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Affiliation(s)
- Katherine M. Keever
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, United States
| | - Ying Li
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, United States
| | - Paige D. Womble
- Department of Psychology and Neuroscience, Baylor University, Waco, TX, United States
| | - D. Gregory Sullens
- Department of Psychology and Neuroscience, Baylor University, Waco, TX, United States
| | - Gonzalo H. Otazu
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, United States
| | - Joaquin N. Lugo
- Department of Psychology and Neuroscience, Baylor University, Waco, TX, United States
| | - Raddy L. Ramos
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, United States
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3
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Mohammadi E, Nikbakht F, Vazifekhah S, Babae JF, Jogataei MT. Evaluation the cognition-improvement effects of N-acetyl cysteine in experimental temporal lobe epilepsy in rat. Behav Brain Res 2023; 440:114263. [PMID: 36563904 DOI: 10.1016/j.bbr.2022.114263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 12/13/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022]
Abstract
Memory impairment is a critical issue in patients with temporal lobe epilepsy (TLE). Neuronal loss within the hippocampus and recurrent seizures may cause cognitive impairment in TLE. N -acetyl cysteine (NAC) is a sulfur-containing amino acid cysteine that is currently being investigated due to its protective effects on neurodegenerative disorders. NAC was orally administrated at a dose of 100 mg/kg for 8 days (7-day pretreatment and 1-day post-surgery). Neuronal viability, mTOR protein level, and spatial memory were detected in the kainite temporal epilepsy model via Nissl staining, western blot method, and Morris water maze task, respectively. Results showed that NAC delayed seizure activity and ameliorated memory deficit induced by Kainic acid. Histological analysis showed that NAC significantly increased the number of intact neurons in CA3 and hilar areas of the hippocampus following the induction of epilepsy. NAC also modulated the mTOR protein level 5 days after epilepsy compared to the KA-induced group. CONCLUSION: These results suggest that NAC improved memory impairment via anticonvulsant and neuroprotective activity and, in all probability, by lowering the level of mTOR.
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Affiliation(s)
- Ekram Mohammadi
- Cellular and Molecular Research Center and Department of Physiology, School of Medicine, University of Medical Sciences, Tehran Iran
| | - Farnaz Nikbakht
- Cellular and Molecular Research Center and Department of Physiology, School of Medicine, University of Medical Sciences, Tehran Iran.
| | - Somayeh Vazifekhah
- Department of Basic Sciences, Sari Branch. Islamic Azad University, Sari, Iran
| | - Javad Fahanik Babae
- Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohamad Taghi Jogataei
- Cellular and Molecular Research Center and Department of Anatomy, School of Medicine, University of Medical Sciences, Tehran Iran
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4
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Park S, Zhu J, Jeong KH, Kim WJ. Adjudin prevents neuronal damage and neuroinflammation via inhibiting mTOR activation against pilocarpine-induced status epilepticus. Brain Res Bull 2022; 182:80-89. [PMID: 35182690 DOI: 10.1016/j.brainresbull.2022.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 01/23/2022] [Accepted: 02/14/2022] [Indexed: 11/02/2022]
Abstract
Inflammatory responses in the brain play an etiological role in the development of epilepsy, suggesting that finding novel molecules for controlling neuroinflammation may have clinical value in developing the disease-modifying strategies for epileptogenesis. Adjudin, a multi-functional small molecule compound, has pleiotropic effects, including anti-inflammatory properties. In the present study, we aimed to investigate the effects of adjudin on pilocarpine-induced status epilepticus (SE) and its role in the regulation of reactive gliosis and neuroinflammation. SE was induced in male C57BL/6 mice that were then treated with adjudin (50mg/kg) for 3 days after SE onset. Immunofluorescence staining, terminal deoxynucleotidyl transferase dUTP nick end labeling staining, and western blot analysis were used to evaluate the effects of adjudin treatment in the hippocampus after SE. Our results showed that adjudin treatment significantly mitigated apoptotic cell death in the hippocampus after SE onset. Moreover, adjudin treatment suppressed SE-induced glial activation and activation of mammalian target of rapamycin signaling in the hippocampus. Concomitantly, adjudin treatment significantly reduced SE-induced inflammatory processes, as confirmed by changes in the expression of inflammatory mediators such as tumor necrosis factor-α, interleukin-1β, and arginase-1. In conclusion, these findings suggest that adjudin may serve as a potential neuroprotective agent for preventing pathological mechanisms implicated in epileptogenesis.
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Affiliation(s)
- Soojin Park
- Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea; Brain Korea 21 Plus Project for Medical Science, Yonsei University, Seoul, Republic of Korea
| | - Jing Zhu
- Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea; Brain Korea 21 Plus Project for Medical Science, Yonsei University, Seoul, Republic of Korea
| | - Kyoung Hoon Jeong
- Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea; Epilepsy Research Institute, Yonsei University College of Medicine, Seoul, Republic of Korea.
| | - Won-Joo Kim
- Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea; Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
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5
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A Flurothyl-Induced Seizure Does Not Disrupt Hippocampal Memory Reconsolidation in C57BL/6J Mice. Epilepsy Res 2022; 181:106867. [DOI: 10.1016/j.eplepsyres.2022.106867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/20/2021] [Accepted: 01/18/2022] [Indexed: 11/24/2022]
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6
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Wang Z, Alderman MH, Asgari C, Taylor HS. Fetal Bisphenol-A Induced Changes in Murine Behavior and Brain Gene Expression Persisted in Adult-aged Offspring. Endocrinology 2020; 161:5905560. [PMID: 32926169 PMCID: PMC7609133 DOI: 10.1210/endocr/bqaa164] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 09/10/2020] [Indexed: 12/17/2022]
Abstract
In utero Bisphenol A (BPA) exposure has been linked to many deficits during brain development, including sexual differentiation, behavior, and motor coordination. Yet, how BPA induces these disorders and whether its effects are long lasting are largely unknown. In this study, using a mouse model, we demonstrated that in utero exposure to an environmentally relevant dose of BPA induced locomotor deficits, anxiety-like behavior, and declarative memory impairments that persisted into old age (18 months). Compared to the control animals, the BPA-exposed mice had a significant decrease in locomotor activity, exploratory tendencies, and long-term memory, and an increase in anxiety. The global brain gene expression profile was altered permanently by BPA treatment and showed regional and sexual differences. The BPA-treated male mice had more changes in the hippocampus, while female mice experienced more changes in the cortex. Overall, we demonstrate that in utero exposure to BPA induces permanent changes in brain gene expression in a region-specific and sex-specific manner, including a significant decrease in locomotor activity, learning ability, long-term memory, and an increase in anxiety. Fetal/early life exposures permanently affect neurobehavioral functions that deteriorate with age; BPA exposure may compound the effects of aging.
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Affiliation(s)
- Zhihao Wang
- Department of Obstetrics, Gynecology & Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut
| | - Myles H Alderman
- Department of Obstetrics, Gynecology & Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut
| | - Cyrus Asgari
- Department of Obstetrics, Gynecology & Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut
| | - Hugh S Taylor
- Department of Obstetrics, Gynecology & Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut
- Correspondence: Hugh S. Taylor, MD, Yale University School of Medicine, Division of Reproductive Endocrinology and Infertility, Department of Obstetrics, Gynecology and Reproductive Sciences, P.O. Box 208063, New Haven, CT 06520-8063, USA. E-mail:
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7
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Binder MS, Kim AD, Lugo JN. An acute seizure prior to memory reactivation transiently impairs associative memory performance in C57BL/6J mice. ACTA ACUST UNITED AC 2020; 27:340-345. [PMID: 32817300 PMCID: PMC7433655 DOI: 10.1101/lm.050633.119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 05/01/2020] [Indexed: 11/25/2022]
Abstract
Memory deficits significantly decrease an individual's quality of life and are a pervasive comorbidity of epilepsy. Despite the various distinct processes of memory, the majority of epilepsy research has focused on seizures during the encoding phase of memory, therefore the effects of a seizure on other memory processes is relatively unknown. In the present study, we investigated how a single seizure affects memory reactivation in C57BL/6J adult mice using an associative conditioning paradigm. Initially, mice were trained to associate a tone (conditioned stimulus), with the presence of a shock (unconditioned stimulus). Flurothyl was then administered 1 h before, 1 h after, or 6 h before a memory reactivation trial. The learned association was then assessed by presenting a conditioned stimulus in a new context 24 h or 1 wk after memory reactivation. We found that mice receiving a seizure 1 h prior to reactivation exhibited a deficit in memory 24 h later but not 1 wk later. When mice were administered a seizure 6 h before or 1 h after reactivation, there were no differences in memory between seizure and control animals. Altogether, our study indicates that an acute seizure during memory reactivation leads to a temporary deficit in associative memory in adult mice. These findings suggest that the cognitive impact of a seizure may depend on the timing of the seizure relative to the memory process that is active.
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Affiliation(s)
- Matthew S Binder
- Department of Psychology and Neuroscience, Baylor University, Waco, Texas 76798, USA
| | - Andrew D Kim
- Department of Psychology and Neuroscience, Baylor University, Waco, Texas 76798, USA
| | - Joaquin N Lugo
- Department of Psychology and Neuroscience, Baylor University, Waco, Texas 76798, USA.,Institute of Biomedical Studies, Baylor University, Waco, Texas 76798, USA.,Department of Biology, Baylor University, Waco, Texas 76798, USA
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8
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Kim K, Hessl D, Randol JL, Espinal GM, Schneider A, Protic D, Aydin EY, Hagerman RJ, Hagerman PJ. Association between IQ and FMR1 protein (FMRP) across the spectrum of CGG repeat expansions. PLoS One 2019; 14:e0226811. [PMID: 31891607 PMCID: PMC6938341 DOI: 10.1371/journal.pone.0226811] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 12/05/2019] [Indexed: 12/20/2022] Open
Abstract
Fragile X syndrome, the leading heritable form of intellectual disability, is caused by hypermethylation and transcriptional silencing of large (CGG) repeat expansions (> 200 repeats) in the 5′ untranslated region of the fragile X mental retardation 1 (FMR1) gene. As a consequence of FMR1 gene silencing, there is little or no production of FMR1 protein (FMRP), an important element in normal synaptic function. Although the absence of FMRP has long been known to be responsible for the cognitive impairment in fragile X syndrome, the relationship between FMRP level and cognitive ability (IQ) is only imprecisely understood. To address this issue, a high-throughput, fluorescence resonance energy transfer (FRET) assay has been used to quantify FMRP levels in dermal fibroblasts, and the relationship between FMRP and IQ measures was assessed by statistical analysis in a cohort of 184 individuals with CGG-repeat lengths spanning normal (< 45 CGGs) to full mutation (> 200 CGGs) repeat ranges in fibroblasts. The principal findings of the current study are twofold: i) For those with normal CGG repeats, IQ is no longer sensitive to further increases in FMRP above an FMRP threshold of ~70% of the mean FMRP level; below this threshold, IQ decreases steeply with further decreases in FMRP; and ii) For the current cohort, a mean IQ of 85 (lower bound for the normal IQ range) is attained for FMRP levels that are only ~35% of the mean FMRP level among normal CGG-repeat controls. The current results should help guide expectations for efforts to induce FMR1 gene activity and for the levels of cognitive function expected for a given range of FMRP levels.
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Affiliation(s)
- Kyoungmi Kim
- UC Davis MIND Institute, UC Davis Health, Sacramento, California, United States of America
- Department of Public Health Sciences, University of California, Davis, School of Medicine, Davis, California, United States of America
| | - David Hessl
- UC Davis MIND Institute, UC Davis Health, Sacramento, California, United States of America
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, School of Medicine, Sacramento, California, United States of America
| | - Jamie L. Randol
- Department of Biochemistry and Molecular Medicine, University of California, Davis, School of Medicine, Davis, California, United States of America
| | - Glenda M. Espinal
- Department of Biochemistry and Molecular Medicine, University of California, Davis, School of Medicine, Davis, California, United States of America
| | - Andrea Schneider
- UC Davis MIND Institute, UC Davis Health, Sacramento, California, United States of America
- Department of Pediatrics, University of California, Davis, School of Medicine, Sacramento, California, United States of America
| | - Dragana Protic
- UC Davis MIND Institute, UC Davis Health, Sacramento, California, United States of America
| | - Elber Yuksel Aydin
- UC Davis MIND Institute, UC Davis Health, Sacramento, California, United States of America
| | - Randi J. Hagerman
- UC Davis MIND Institute, UC Davis Health, Sacramento, California, United States of America
- Department of Pediatrics, University of California, Davis, School of Medicine, Sacramento, California, United States of America
| | - Paul J. Hagerman
- UC Davis MIND Institute, UC Davis Health, Sacramento, California, United States of America
- Department of Biochemistry and Molecular Medicine, University of California, Davis, School of Medicine, Davis, California, United States of America
- * E-mail:
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9
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Neuronal deletion of phosphatase and tensin homolog results in cerebellar motor learning dysfunction and alterations in intracellular signaling. Neuroreport 2019; 30:556-561. [PMID: 30920436 DOI: 10.1097/wnr.0000000000001241] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The purpose of this investigation was to examine cerebellar levels of several molecular signaling pathways, including PI3K/AKT/mammalian target of rapamycin (mTOR) signaling and markers of neuronal migration, following loss of the phosphatase and tensin homolog (PTEN) gene in a subset of neurons, as well as the accompanying behavior phenotype in mice. Motor coordination and learning were measured by the sticker removal task and the accelerating rotarod. Western blots were conducted on cerebellar tissue samples. We demonstrated that neuron subset-specific deletion of PTEN in mice led to deficits in motor coordination. These changes were accompanied by alterations in many different proteins, including the PI3K/AKT/mTOR signaling pathway, FMRP, glutamate receptors, and neuronal migration markers. These data firstly support a role for hyperactivation of mTOR in the cerebellum following the loss of PTEN, accompanied by behavioral deficits. Moreover, the results of the current study support a broader role for PTEN signaling in early neuronal migration and organization of the cerebellum, and point to a putative role for PTEN in many neuropsychiatric conditions.
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10
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Hodges SL, Reynolds CD, Nolan SO, Huebschman JL, Okoh JT, Binder MS, Lugo JN. A single early-life seizure results in long-term behavioral changes in the adult Fmr1 knockout mouse. Epilepsy Res 2019; 157:106193. [PMID: 31520894 PMCID: PMC6823160 DOI: 10.1016/j.eplepsyres.2019.106193] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 08/06/2019] [Accepted: 08/28/2019] [Indexed: 12/20/2022]
Abstract
Fragile X syndrome (FXS) is the leading cause of inherited intellectual disability and a significant genetic contributor to Autism spectrum disorder. In addition to autistic-like phenotypes, individuals with FXS are subject to developing numerous comorbidities, one of the most prevalent being seizures. In the present study, we investigated how a single early-life seizure superimposed on a genetic condition impacts the autistic-like behavioral phenotype of the mouse. We induced status epilepticus (SE) on postnatal day (PD) 10 in Fmr1 wild type (WT) and knockout (KO) mice. We then tested the mice in a battery of behavioral tests during adulthood (PD90) to examine the long-term impact of an early-life seizure. Our findings replicated prior work that reported a single instance of SE results in behavioral deficits, including increases in repetitive behavior, enhanced hippocampal-dependent learning, and reduced sociability and prepulse inhibition (p < 0.05). We also observed genotypic differences characteristic of the FXS phenotype in Fmr1 KO mice, such as enhanced prepulse inhibition and repetitive behavior, hyperactivity, and reduced startle responses (p < 0.05). Superimposing a seizure on deletion of Fmr1 significantly impacted repetitive behavior in a nosepoke task. Specifically, a single early-life seizure increased consecutive nose poking behavior in the task in WT mice (p < 0.05), yet seizures did not exacerbate the elevated stereotypy observed in Fmr1 KO mice (p > 0.05). Overall, these findings help to elucidate how seizures in a critical period of development can impact long-term behavioral manifestations caused by underlying gene mutations in Fmr1. Utilizing double-hit models, such as superimposing seizures on the Fmr1 mutation, can help to enhance our understanding of comorbidities in disease models.
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Affiliation(s)
- Samantha L Hodges
- Institute of Biomedical Studies, Baylor University, Waco, TX 76798, USA
| | - Conner D Reynolds
- Texas College of Osteopathic Medicine, University of North Texas Health Science Center, Fort Worth TX, 76107, USA
| | - Suzanne O Nolan
- Department of Psychology and Neuroscience, Baylor University, Waco, TX 76798, USA
| | | | - James T Okoh
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Matthew S Binder
- Department of Psychology and Neuroscience, Baylor University, Waco, TX 76798, USA
| | - Joaquin N Lugo
- Institute of Biomedical Studies, Baylor University, Waco, TX 76798, USA; Department of Psychology and Neuroscience, Baylor University, Waco, TX 76798, USA; Department of Biology, Baylor University, Waco, TX 76798, USA.
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11
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Zhu X, Zhang A, Dong J, Yao Y, Zhu M, Xu K, Al Hamda MH. MicroRNA-23a contributes to hippocampal neuronal injuries and spatial memory impairment in an experimental model of temporal lobe epilepsy. Brain Res Bull 2019; 152:175-183. [PMID: 31336125 DOI: 10.1016/j.brainresbull.2019.07.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 07/05/2019] [Accepted: 07/18/2019] [Indexed: 10/26/2022]
Abstract
Temporal lobe epilepsy (TLE) is the most common form of epilepsy characterized by spontaneous recurrent seizures. It has been widely accepted that individuals with TLE tend to have neuronal injuries and memory impairment. However, little is known about the underlying molecular mechanisms. MicroRNAs (miRNAs) are small noncoding RNAs that regulate the expression of target genes at the posttranscriptional level. An increasing body of evidence suggests that miRNAs play pivotal roles in the pathogenesis of epilepsy. Here, we sought to determine the role of miR-23a, one of the most common miRNAs involved in various cancer types, in hippocampal neuronal injuries and spatial memory impairment in an experimental model of TLE. We found that miR-23a is upregulated in the hippocampus after status epilepticus (SE) in kanic acid (KA)-induced TLE mice. Furthermore, the upregulation of miR-23a is accompanied by hippocampal oxidative damage, neuronal injuries and spatial memory impairment in TLE mice. Inhibition of miR-23a expression by miR-23a antagomirs reduced hippocampal oxidative stress, neuronal injuries and improved spatial memory, while an increase in miR-23a expression by miR-23a agomir exacerbated hippocampal oxidative stress, neuronal injuries and spatial memory impairment in TLE mice. Our findings suggest that miR-23a contributes to hippocampal oxidative damage and neuronal injuries, which may consequently contribute to spatial memory impairment in TLE mice. Thus, targeting miR-23a in the epileptic brain may provide a novel strategy for protecting against hippocampal neuronal injuries and improving spatial memory in TLE patients.
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Affiliation(s)
- Xinjian Zhu
- Department of Pharmacology, Medical School of Southeast University, Nanjing, China.
| | - Aifeng Zhang
- Department of Pathology, Medical School of Southeast University, Nanjing, China
| | - Jingde Dong
- Department of Geriatric Neurology, Nanjing Brain Hospital Affiliated with Nanjing Medical University, Nanjing, China
| | - Yuanyuan Yao
- Department of Pharmacology, Medical School of Southeast University, Nanjing, China
| | - Mengyi Zhu
- Department of Pharmacology, Medical School of Southeast University, Nanjing, China
| | - Kangni Xu
- Department of Pharmacology, Medical School of Southeast University, Nanjing, China
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