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Buchanan RA, Wang Y, May JM, Harrison FE. Ascorbate insufficiency disrupts glutamatergic signaling and alters electroencephalogram phenotypes in a mouse model of Alzheimer's disease. Neurobiol Dis 2024; 199:106602. [PMID: 39004234 DOI: 10.1016/j.nbd.2024.106602] [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] [Received: 01/12/2024] [Revised: 07/08/2024] [Accepted: 07/09/2024] [Indexed: 07/16/2024] Open
Abstract
Clinical studies have reported that increased epileptiform and subclinical epileptiform activity can be detected in many patients with an Alzheimer's disease (AD) diagnosis using electroencephalogram (EEG) and this may correlate with poorer cognition. Ascorbate may have a specific role as a neuromodulator in AD as it is released concomitantly with glutamate reuptake following excitatory neurotransmission. Insufficiency may therefore result in an exacerbated excitatory/inhibitory imbalance in neuronal signaling. Using a mouse model of AD that requires dietary ascorbate (Gulo-/-APPswe/PSEN1dE9), EEG was recorded at baseline and during 4 weeks of ascorbate depletion in young (5-month-old) and aged (20-month-old) animals. Data were scored for changes in quantity of spike trains, individual spikes, sleep-wake rhythms, sleep fragmentation, and brainwave power bands during light periods each week. We found an early increase in neuronal spike discharges with age and following ascorbate depletion in AD model mice and not controls, which did not correlate with brain amyloid load. Our data also show more sleep fragmentation with age and with ascorbate depletion. Additionally, changes in brain wave activity were observed within different vigilance states in both young and aged mice, where Gulo-/-APPswe/PSEN1dE9 mice had shifts towards higher frequency bands (alpha, beta, and gamma) and ascorbate depletion resulted in shifts towards lower frequency bands (delta and theta). Microarray data supported ascorbate insufficiency altering glutamatergic transmission through the decreased expression of glutamate related genes, however no changes in protein expression of glutamate reuptake transporters were observed. These data suggest that maintaining optimal brain ascorbate levels may support normal brain electrical activity and sleep patterns, particularly in AD patient populations where disruptions are observed.
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Affiliation(s)
- Rebecca A Buchanan
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, United States
| | - Yuhan Wang
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - James M May
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Fiona E Harrison
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, United States; Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States.
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Xu Y, Zhang L, Yan Y, Xiao W, Zou W, Luo Z, Xiao B, Long H. MicroRNA-33 regulates the synaptic plasticity-related gene ARC in temporal lobe epilepsy. Neurosci Res 2024:S0168-0102(24)00109-3. [PMID: 39214315 DOI: 10.1016/j.neures.2024.08.003] [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: 01/13/2024] [Revised: 08/15/2024] [Accepted: 08/27/2024] [Indexed: 09/04/2024]
Abstract
This study aimed to elucidate the expression patterns of miR-33 and ARC in both a rat model of temporal lobe epilepsy (TLE) and human TLE patients, to explore the role of miR-33 in epilepsy onset through its regulation of ARC expression in the hippocampus. Our findings, supported by a Dual-Luciferase reporter assay, suggest that miR-33 can bind to the 3' UTR region of ARC. We observed that miR-33 levels were reduced at 1 hour and 60 days post-seizure, while ARC expression notably increased at these time points. In the hippocampal CA1 and CA3 regions of post-seizure rats, ARC expression significantly exceeded that of control groups. Following the transfection of HEK cells with a miR-33 mimic, there was a decrease in both ARC mRNA and protein levels, whereas the group treated with a miR-33 inhibitor displayed the opposite effect. RNA sequencing in TLE patients revealed a similar miR-33 and ARC interaction. The regulation of Arc expression by miR-33 suggests that Arc may be a target gene of miR-33 in the context of epilepsy. Our findings indicate that miR-33 downregulation could contribute to the dysregulation of Arc expression observed in TLE, potentially influencing the disease process. Further studies are required to establish the exact role of miR-33-mediated Arc regulation in the development of epilepsy.
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Affiliation(s)
- Yuchen Xu
- Department of Neurology, The First Affiliated Hospital of Wenzhou Medical University, Zhejiang, China.
| | - Lily Zhang
- Neurology Department, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yan Yan
- Neurology Department, Loudi Central Hospital, Loudi, Hunan, China
| | - Wenbiao Xiao
- Neurology Department, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Wei Zou
- NHC Key Laboratory of Birth Defects Research, Prevention, and Treatment, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China
| | - Zhaohui Luo
- Neurology Department, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Bo Xiao
- Neurology Department, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Hongyu Long
- Neurology Department, Xiangya Hospital, Central South University, Changsha, Hunan, China.
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Li L, Liu Z. SRF Facilitates Transcriptional Inhibition of Gem Expression by m6A Methyltransferase METTL3 to Suppress Neuronal Damage in Epilepsy. Mol Neurobiol 2024:10.1007/s12035-024-04396-x. [PMID: 39190265 DOI: 10.1007/s12035-024-04396-x] [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: 11/01/2023] [Accepted: 07/21/2024] [Indexed: 08/28/2024]
Abstract
A bioinformatics analysis was conducted to screen for relevant expression datasets of the transcription factor SRF knockout mice. The aim was to investigate the relationship between SRF and m6A-related genes, predict how SRF regulates the m6A modification of GEM genes mediated by METTL3, and explore potential molecular mechanisms associated with neurotrauma. Disease gene databases such as GeneCards, DisGeNET, and Phenolyzer, and transcription factor databases TFDB and TRRUST, were used to obtain epilepsy-related genes and transcription factors. The intersection was then selected. Expression data of SRF knockout epilepsy mice were obtained from the GEO database and used to filter differentially expressed genes. Important module genes related to the disease were selected through WGCNA co-expression analysis. The intersection between these genes and the differentially expressed genes was performed, followed by PPI network analysis and GO/KEGG enrichment analysis. Furthermore, the core genes were selected using the cytoHubba plugin of the Cytoscape software. Differential expression analysis was performed on m6A-related factors in the GEO dataset, and the relationship between SRF and m6A-related factors and core genes was analyzed. The m6A binding sites of SRF with the METTL3 promoter and target gene Gem were predicted using the AnimalTFDB and SRAMP websites, respectively. We found that the transcription factor SRF may be a key gene in epilepsy during neuronal development. Further WGCNA analysis showed that 129 module genes were associated with SRF knockout epilepsy, and these differentially expressed genes were mainly enriched in the neuroactive ligand-receptor interaction pathway. The final results indicate that knocking out SRF may inhibit the transcription of METTL3, thereby inhibiting the m6A modification of Gem and leading to upregulation of Gem expression, thereby playing an important role in neuronal damage. Knocking out the SRF gene may inhibit the transcription of m6A methyltransferase METTL3, thereby inhibiting the m6A modification of GEM genes mediated by METTL3, promoting GEM gene expression, and leading to the occurrence of epilepsy-related neuron injury. Further investigation revealed that SRF overexpression can potentially enhance the transcription of METTL3, thus promoting m6A modification of GEM, resulting in downregulation of GEM expression. This process regulates oxidative stress in epileptic mouse neurons, suppresses inflammatory responses, and mitigates associated damage. Additionally, an in vitro neuronal epileptic model was established, and experimental techniques such as qRT-PCR and WB were employed to assess the expression of SRF, METTL3, and GEM in hippocampal tissues and neurons. The experimental results were consistent with our predictions, demonstrating that overexpression of SRF can inhibit the development of epilepsy-related neuronal damage. This study reveals that knockout of the SRF gene may suppress the transcription of m6A methyltransferase METTL3, thereby inhibiting m6A modification of the GEM gene mediated by METTL3 and subsequently promoting the expression of the GEM gene, leading to the occurrence of epilepsy-related neuronal damage.
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Affiliation(s)
- Lianling Li
- Department of Neurosurgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, Henan Province, P. R. China.
| | - Zhiguo Liu
- Department of Neurosurgery, Centtal Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, 250012, P. R. China
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Spagnoli G, Parrella E, Ghazanfar Tehrani S, Mengoni F, Salari V, Nistreanu C, Scambi I, Sbarbati A, Bertini G, Fabene PF. Glial Response and Neuronal Modulation Induced by Epidural Electrode Implant in the Pilocarpine Mouse Model of Epilepsy. Biomolecules 2024; 14:834. [PMID: 39062548 PMCID: PMC11274793 DOI: 10.3390/biom14070834] [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: 05/01/2024] [Revised: 06/23/2024] [Accepted: 07/01/2024] [Indexed: 07/28/2024] Open
Abstract
In animal models of epilepsy, cranial surgery is often required to implant electrodes for electroencephalography (EEG) recording. However, electrode implants can lead to the activation of glial cells and interfere with physiological neuronal activity. In this study, we evaluated the impact of epidural electrode implants in the pilocarpine mouse model of temporal lobe epilepsy. Brain neuroinflammation was assessed 1 and 3 weeks after surgery by cytokines quantification, immunohistochemistry, and western blotting. Moreover, we investigated the effect of pilocarpine, administered two weeks after surgery, on mice mortality rate. The reported results indicate that implanted mice suffer from neuroinflammation, characterized by an early release of pro-inflammatory cytokines, microglia activation, and subsequent astrogliosis, which persists after three weeks. Notably, mice subjected to electrode implants displayed a higher mortality rate following pilocarpine injection 2 weeks after the surgery. Moreover, the analysis of EEGs recorded from implanted mice revealed a high number of single spikes, indicating a possible increased susceptibility to seizures. In conclusion, epidural electrode implant in mice promotes neuroinflammation that could lower the seizure thresholds to pilocarpine and increase the death rate. An improved protocol considering the persistent neuroinflammation induced by electrode implants will address refinement and reduction, two of the 3Rs principles for the ethical use of animals in scientific research.
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Affiliation(s)
- Giulia Spagnoli
- Section of Anatomy and Histology, Department of Neurosciences, Biomedicine, and Movement Science, School of Medicine, University of Verona, 37124 Verona, Italy; (G.S.); (E.P.); (S.G.T.); (F.M.); (C.N.); (I.S.); (A.S.); (G.B.)
| | - Edoardo Parrella
- Section of Anatomy and Histology, Department of Neurosciences, Biomedicine, and Movement Science, School of Medicine, University of Verona, 37124 Verona, Italy; (G.S.); (E.P.); (S.G.T.); (F.M.); (C.N.); (I.S.); (A.S.); (G.B.)
- Section of Innovation Biomedicine, Department of Engineering for Innovation Medicine, University of Verona, 37134 Verona, Italy;
| | - Sara Ghazanfar Tehrani
- Section of Anatomy and Histology, Department of Neurosciences, Biomedicine, and Movement Science, School of Medicine, University of Verona, 37124 Verona, Italy; (G.S.); (E.P.); (S.G.T.); (F.M.); (C.N.); (I.S.); (A.S.); (G.B.)
| | - Francesca Mengoni
- Section of Anatomy and Histology, Department of Neurosciences, Biomedicine, and Movement Science, School of Medicine, University of Verona, 37124 Verona, Italy; (G.S.); (E.P.); (S.G.T.); (F.M.); (C.N.); (I.S.); (A.S.); (G.B.)
| | - Valentina Salari
- Section of Innovation Biomedicine, Department of Engineering for Innovation Medicine, University of Verona, 37134 Verona, Italy;
| | - Cristina Nistreanu
- Section of Anatomy and Histology, Department of Neurosciences, Biomedicine, and Movement Science, School of Medicine, University of Verona, 37124 Verona, Italy; (G.S.); (E.P.); (S.G.T.); (F.M.); (C.N.); (I.S.); (A.S.); (G.B.)
| | - Ilaria Scambi
- Section of Anatomy and Histology, Department of Neurosciences, Biomedicine, and Movement Science, School of Medicine, University of Verona, 37124 Verona, Italy; (G.S.); (E.P.); (S.G.T.); (F.M.); (C.N.); (I.S.); (A.S.); (G.B.)
| | - Andrea Sbarbati
- Section of Anatomy and Histology, Department of Neurosciences, Biomedicine, and Movement Science, School of Medicine, University of Verona, 37124 Verona, Italy; (G.S.); (E.P.); (S.G.T.); (F.M.); (C.N.); (I.S.); (A.S.); (G.B.)
| | - Giuseppe Bertini
- Section of Anatomy and Histology, Department of Neurosciences, Biomedicine, and Movement Science, School of Medicine, University of Verona, 37124 Verona, Italy; (G.S.); (E.P.); (S.G.T.); (F.M.); (C.N.); (I.S.); (A.S.); (G.B.)
| | - Paolo Francesco Fabene
- Section of Anatomy and Histology, Department of Neurosciences, Biomedicine, and Movement Science, School of Medicine, University of Verona, 37124 Verona, Italy; (G.S.); (E.P.); (S.G.T.); (F.M.); (C.N.); (I.S.); (A.S.); (G.B.)
- Section of Innovation Biomedicine, Department of Engineering for Innovation Medicine, University of Verona, 37134 Verona, Italy;
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Popova EY, Kawasawa YI, Leung M, Barnstable CJ. Temporal changes in mouse hippocampus transcriptome after pilocarpine-induced seizures. Front Neurosci 2024; 18:1384805. [PMID: 39040630 PMCID: PMC11260795 DOI: 10.3389/fnins.2024.1384805] [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: 02/10/2024] [Accepted: 06/07/2024] [Indexed: 07/24/2024] Open
Abstract
Introduction Status epilepticus (SE) is a seizure lasting more than 5 min that can have lethal consequences or lead to various neurological disorders, including epilepsy. Using a pilocarpine-induced SE model in mice we investigated temporal changes in the hippocampal transcriptome. Methods We performed mRNA-seq and microRNA-seq analyses at various times after drug treatment. Results At 1 h after the start of seizures, hippocampal cells upregulated transcription of immediate early genes and genes involved in the IGF-1, ERK/MAPK and RNA-PolII/transcription pathways. At 8 h, we observed changes in the expression of genes associated with oxidative stress, overall transcription downregulation, particularly for genes related to mitochondrial structure and function, initiation of a stress response through regulation of ribosome and translation/EIF2 signaling, and upregulation of an inflammatory response. During the middle of the latent period, 36 h, we identified upregulation of membrane components, cholesterol synthesis enzymes, channels, and extracellular matrix (ECM), as well as an increased inflammatory response. At the end of the latent period, 120 h, most changes in expression were in genes involved in ion transport, membrane channels, and synapses. Notably, we also elucidated the involvement of novel pathways, such as cholesterol biosynthesis pathways, iron/BMP/ferroptosis pathways, and circadian rhythms signaling in SE and epileptogenesis. Discussion These temporal changes in metabolic reactions indicate an immediate response to injury followed by recovery and regeneration. CREB was identified as the main upstream regulator. Overall, our data provide new insights into molecular functions and cellular processes involved at different stages of seizures and offer potential avenues for effective therapeutic strategies.
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Affiliation(s)
- Evgenya Y. Popova
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, PA, United States
- Penn State Hershey Eye Center, Hershey, PA, United States
| | - Yuka Imamura Kawasawa
- Department of Pharmacology, Penn State University College of Medicine, Hershey, PA, United States
- Center for Cancer Genomics and Precision Oncology, Wake Forest Baptist Comprehensive Cancer Center, Winston Salem, NC, United States
| | - Ming Leung
- Center for Cancer Genomics and Precision Oncology, Wake Forest Baptist Comprehensive Cancer Center, Winston Salem, NC, United States
| | - Colin J. Barnstable
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, PA, United States
- Penn State Hershey Eye Center, Hershey, PA, United States
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Vaughan AJ, McMeekin LJ, Hine K, Stubbs IW, Codadu NK, Cockell S, Hill JT, Cowell R, Trevelyan AJ, Parrish RR. RNA Sequencing Demonstrates Ex Vivo Neocortical Transcriptomic Changes Induced by Epileptiform Activity in Male and Female Mice. eNeuro 2024; 11:ENEURO.0520-23.2024. [PMID: 38664009 PMCID: PMC11129778 DOI: 10.1523/eneuro.0520-23.2024] [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: 11/29/2023] [Revised: 04/13/2024] [Accepted: 04/18/2024] [Indexed: 05/26/2024] Open
Abstract
Seizures are generally associated with epilepsy but may also be a symptom of many other neurological conditions. A hallmark of a seizure is the intensity of the local neuronal activation, which can drive large-scale gene transcription changes. Such changes in the transcriptional profile likely alter neuronal function, thereby contributing to the pathological process. Therefore, there is a strong clinical imperative to characterize how gene expression is changed by seizure activity. To this end, we developed a simplified ex vivo technique for studying seizure-induced transcriptional changes. We compared the RNA sequencing profile in mouse neocortical tissue with up to 3 h of epileptiform activity induced by 4-aminopyridine (4AP) relative to control brain slices not exposed to the drug. We identified over 100 genes with significantly altered expression after 4AP treatment, including multiple genes involved in MAPK, TNF, and neuroinflammatory signaling pathways, all of which have been linked to epilepsy previously. Notably, the patterns in male and female brain slices were almost identical. Various immediate early genes were among those showing the largest upregulation. The set of down-regulated genes included ones that might be expected either to increase or to decrease neuronal excitability. In summary, we found the seizure-induced transcriptional profile complex, but the changes aligned well with an analysis of published epilepsy-associated genes. We discuss how simple models may provide new angles for investigating seizure-induced transcriptional changes.
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Affiliation(s)
- Alec J Vaughan
- Department of Cell Biology and Physiology, Brigham Young University, Provo, Utah 84602
| | - Laura J McMeekin
- Department of Neurology, University of Alabama, Birmingham, Birmingham, Alabama 35233
| | - Kutter Hine
- Department of Cell Biology and Physiology, Brigham Young University, Provo, Utah 84602
| | - Isaac W Stubbs
- Department of Cell Biology and Physiology, Brigham Young University, Provo, Utah 84602
| | - Neela K Codadu
- Newcastle University Biosciences Institute, Medical School, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Simon Cockell
- School of Biomedical, Nutritional and Sports Science, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Jonathon T Hill
- Department of Cell Biology and Physiology, Brigham Young University, Provo, Utah 84602
| | - Rita Cowell
- Department of Neurology, University of Alabama, Birmingham, Birmingham, Alabama 35233
| | - Andrew J Trevelyan
- Newcastle University Biosciences Institute, Medical School, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - R Ryley Parrish
- Department of Cell Biology and Physiology, Brigham Young University, Provo, Utah 84602
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Tsuboi D, Nagai T, Yoshimoto J, Kaibuchi K. Neuromodulator regulation and emotions: insights from the crosstalk of cell signaling. Front Mol Neurosci 2024; 17:1376762. [PMID: 38516040 PMCID: PMC10954900 DOI: 10.3389/fnmol.2024.1376762] [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: 01/26/2024] [Accepted: 02/26/2024] [Indexed: 03/23/2024] Open
Abstract
The unraveling of the regulatory mechanisms that govern neuronal excitability is a major challenge for neuroscientists worldwide. Neurotransmitters play a critical role in maintaining the balance between excitatory and inhibitory activity in the brain. The balance controls cognitive functions and emotional responses. Glutamate and γ-aminobutyric acid (GABA) are the primary excitatory and inhibitory neurotransmitters of the brain, respectively. Disruptions in the balance between excitatory and inhibitory transmission are implicated in several psychiatric disorders, including anxiety disorders, depression, and schizophrenia. Neuromodulators such as dopamine and acetylcholine control cognition and emotion by regulating the excitatory/inhibitory balance initiated by glutamate and GABA. Dopamine is closely associated with reward-related behaviors, while acetylcholine plays a role in aversive and attentional behaviors. Although the physiological roles of neuromodulators have been extensively studied neuroanatomically and electrophysiologically, few researchers have explored the interplay between neuronal excitability and cell signaling and the resulting impact on emotion regulation. This review provides an in-depth understanding of "cell signaling crosstalk" in the context of neuronal excitability and emotion regulation. It also anticipates that the next generation of neurochemical analyses, facilitated by integrated phosphorylation studies, will shed more light on this topic.
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Affiliation(s)
- Daisuke Tsuboi
- Division of Cell Biology, International Center for Brain Science, Fujita Health University, Toyoake, Aichi, Japan
| | - Taku Nagai
- Division of Behavioral Neuropharmacology, International Center for Brain Science, Fujita Health University, Toyoake, Aichi, Japan
| | - Junichiro Yoshimoto
- Department of Biomedical Data Science, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Kozo Kaibuchi
- Division of Cell Biology, International Center for Brain Science, Fujita Health University, Toyoake, Aichi, Japan
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McGann AM, Westerkamp GC, Chalasani A, Danzer CSK, Parkins EV, Rajathi V, Horn PS, Pedapati EV, Tiwari D, Danzer SC, Gross C. MiR-324-5p inhibition after intrahippocampal kainic acid-induced status epilepticus does not prevent epileptogenesis in mice. Front Neurol 2023; 14:1280606. [PMID: 38033777 PMCID: PMC10687438 DOI: 10.3389/fneur.2023.1280606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 10/20/2023] [Indexed: 12/02/2023] Open
Abstract
Background Acquired epilepsies are caused by an initial brain insult that is followed by epileptogenesis and finally the development of spontaneous recurrent seizures. The mechanisms underlying epileptogenesis are not fully understood. MicroRNAs regulate mRNA translation and stability and are frequently implicated in epilepsy. For example, antagonism of a specific microRNA, miR-324-5p, before brain insult and in a model of chronic epilepsy decreases seizure susceptibility and frequency, respectively. Here, we tested whether antagonism of miR-324-5p during epileptogenesis inhibits the development of epilepsy. Methods We used the intrahippocampal kainic acid (IHpKa) model to initiate epileptogenesis in male wild type C57BL/6 J mice aged 6-8 weeks. Twenty-four hours after IHpKa, we administered a miR-324-5p or scrambled control antagomir intracerebroventricularly and implanted cortical surface electrodes for EEG monitoring. EEG data was collected for 28 days and analyzed for seizure frequency and duration, interictal spike activity, and EEG power. Brains were collected for histological analysis. Results Histological analysis of brain tissue showed that IHpKa caused characteristic hippocampal damage in most mice regardless of treatment. Antagomir treatment did not affect latency to, frequency, or duration of spontaneous recurrent seizures or interictal spike activity but did alter the temporal development of frequency band-specific EEG power. Conclusion These results suggest that miR-324-5p inhibition during epileptogenesis induced by status epilepticus does not convey anti-epileptogenic effects despite having subtle effects on EEG frequency bands. Our results highlight the importance of timing of intervention across epilepsy development and suggest that miR-324-5p may act primarily as a proconvulsant rather than a pro-epileptogenic regulator.
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Affiliation(s)
- Amanda M. McGann
- Medical Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
| | - Grace C. Westerkamp
- Division of Child and Adolescent Psychiatry, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
| | - Alisha Chalasani
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
| | - Cole S. K. Danzer
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
| | - Emma V. Parkins
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
| | - Valerine Rajathi
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
| | - Paul S. Horn
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Ernest V. Pedapati
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
- Division of Child and Adolescent Psychiatry, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Durgesh Tiwari
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Steve C. Danzer
- Medical Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Division of Anesthesia, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
- Department of Anesthesia, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Christina Gross
- Medical Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
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9
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Soon HR, Gaunt JR, Bansal VA, Lenherr C, Sze SK, Ch’ng TH. Seizure enhances SUMOylation and zinc-finger transcriptional repression in neuronal nuclei. iScience 2023; 26:107707. [PMID: 37694138 PMCID: PMC10483055 DOI: 10.1016/j.isci.2023.107707] [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: 04/10/2023] [Revised: 05/29/2023] [Accepted: 08/21/2023] [Indexed: 09/12/2023] Open
Abstract
A single episode of pilocarpine-induced status epilepticus can trigger the development of spontaneous recurrent seizures in a rodent model for epilepsy. The initial seizure-induced events in neuronal nuclei that lead to long-term changes in gene expression and cellular responses likely contribute toward epileptogenesis. Using a transgenic mouse model to specifically isolate excitatory neuronal nuclei, we profiled the seizure-induced nuclear proteome via tandem mass tag mass spectrometry and observed robust enrichment of nuclear proteins associated with the SUMOylation pathway. In parallel with nuclear proteome, we characterized nuclear gene expression by RNA sequencing which provided insights into seizure-driven transcriptional regulation and dynamics. Strikingly, we saw widespread downregulation of zinc-finger transcription factors, specifically proteins that harbor Krüppel-associated box (KRAB) domains. Our results provide a detailed snapshot of nuclear events induced by seizure activity and demonstrate a robust method for cell-type-specific nuclear profiling that can be applied to other cell types and models.
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Affiliation(s)
- Hui Rong Soon
- School of Biological Science, Nanyang Technological University, Singapore 636551, Singapore
| | - Jessica Ruth Gaunt
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore
| | - Vibhavari Aysha Bansal
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore
| | - Clara Lenherr
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore
- Centre for Discovery Brain Science, The University of Edinburgh, Edinburgh, UK
| | - Siu Kwan Sze
- Faculty of Applied Health Sciences, Brock University, St. Catherines, ON, Canada
| | - Toh Hean Ch’ng
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore
- School of Biological Science, Nanyang Technological University, Singapore 636551, Singapore
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Lillo A, Serrano-Marín J, Lillo J, Raïch I, Navarro G, Franco R. Differential Gene Expression in Activated Microglia Treated with Adenosine A 2A Receptor Antagonists Highlights Olfactory Receptor 56 and T-Cell Activation GTPase-Activating Protein 1 as Potential Biomarkers of the Polarization of Activated Microglia. Cells 2023; 12:2213. [PMID: 37759436 PMCID: PMC10526142 DOI: 10.3390/cells12182213] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 08/26/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023] Open
Abstract
Microglial activation often accompanies the plastic changes occurring in the brain of patients with neurodegenerative diseases. A2A and A3 adenosine receptors have been proposed as therapeutic targets to combat neurodegeneration. RNAseq was performed using samples isolated from lipopolysaccharide/interferon-γ activated microglia treated with SCH 58261, a selective A2A receptor antagonist, and with both SCH 58261 and 2-Cl-IB-MECA, a selective A3 receptor agonist. None of the treatments led to any clear microglial phenotype when gene expression for classical biomarkers of microglial polarization was assessed. However, many of the downregulated genes were directly or indirectly related to immune system-related events. Searching for genes whose expression was both significantly and synergistically affected when treated with the two adenosine receptor ligands, the AC122413.1 and Olfr56 were selected among those that were, respectively, upregulated and downregulated. We therefore propose that the products of these genes, olfactory receptor 56 and T-cell activation GTPase-activating protein 1, deserve attention as potential biomarkers of phenotypes that occur upon microglial activation.
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Affiliation(s)
- Alejandro Lillo
- Department of Biochemistry and Physiology, School of Pharmacy and Food Science, Universitat de Barcelona, 08007 Barcelona, Spain; (A.L.); (J.L.); (I.R.); (G.N.)
- CiberNed, Network Center for Neurodegenerative Diseases, National Spanish Health Institute Carlos III, 28029 Madrid, Spain
| | - Joan Serrano-Marín
- Molecular Neurobiology Laboratory, Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Universitat de Barcelona, 08028 Barcelona, Spain;
| | - Jaume Lillo
- Department of Biochemistry and Physiology, School of Pharmacy and Food Science, Universitat de Barcelona, 08007 Barcelona, Spain; (A.L.); (J.L.); (I.R.); (G.N.)
- Molecular Neurobiology Laboratory, Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Universitat de Barcelona, 08028 Barcelona, Spain;
| | - Iu Raïch
- Department of Biochemistry and Physiology, School of Pharmacy and Food Science, Universitat de Barcelona, 08007 Barcelona, Spain; (A.L.); (J.L.); (I.R.); (G.N.)
- Molecular Neurobiology Laboratory, Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Universitat de Barcelona, 08028 Barcelona, Spain;
| | - Gemma Navarro
- Department of Biochemistry and Physiology, School of Pharmacy and Food Science, Universitat de Barcelona, 08007 Barcelona, Spain; (A.L.); (J.L.); (I.R.); (G.N.)
- CiberNed, Network Center for Neurodegenerative Diseases, National Spanish Health Institute Carlos III, 28029 Madrid, Spain
- Institute of Neurosciences, Universitat de Barcelona, 08007 Barcelona, Spain
| | - Rafael Franco
- CiberNed, Network Center for Neurodegenerative Diseases, National Spanish Health Institute Carlos III, 28029 Madrid, Spain
- Molecular Neurobiology Laboratory, Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Universitat de Barcelona, 08028 Barcelona, Spain;
- School of Chemistry, Universitat de Barcelona, 08028 Barcelona, Spain
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11
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Song J, Dikwella N, Sinske D, Roselli F, Knöll B. SRF deletion results in earlier disease onset in a mouse model of amyotrophic lateral sclerosis. JCI Insight 2023; 8:e167694. [PMID: 37339001 PMCID: PMC10445689 DOI: 10.1172/jci.insight.167694] [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] [Received: 12/02/2022] [Accepted: 06/16/2023] [Indexed: 06/22/2023] Open
Abstract
Changes in neuronal activity modulate the vulnerability of motoneurons (MNs) in neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). So far, the molecular basis of neuronal activity's impact in ALS is poorly understood. Herein, we investigated the impact of deleting the neuronal activity-stimulated transcription factor (TF) serum response factor (SRF) in MNs of SOD1G93A mice. SRF was present in vulnerable MMP9+ MNs. Ablation of SRF in MNs induced an earlier disease onset starting around 7-8 weeks after birth, as revealed by enhanced weight loss and decreased motor ability. This earlier disease onset in SRF-depleted MNs was accompanied by a mild elevation of neuroinflammation and neuromuscular synapse degeneration, whereas overall MN numbers and mortality were unaffected. In SRF-deficient mice, MNs showed impaired induction of autophagy-encoding genes, suggesting a potentially new SRF function in transcriptional regulation of autophagy. Complementary, constitutively active SRF-VP16 enhanced autophagy-encoding gene transcription and autophagy progression in cells. Furthermore, SRF-VP16 decreased ALS-associated aggregate induction. Chemogenetic modulation of neuronal activity uncovered SRF as having important TF-mediating activity-dependent effects, which might be beneficial to reduce ALS disease burden. Thus, our data identify SRF as a gene regulator connecting neuronal activity with the cellular autophagy program initiated in degenerating MNs.
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Affiliation(s)
- Jialei Song
- Institute of Neurobiochemistry and
- Department of Neurology, Ulm University, Ulm, Germany
| | - Natalie Dikwella
- Institute of Neurobiochemistry and
- Department of Neurology, Ulm University, Ulm, Germany
| | | | - Francesco Roselli
- Department of Neurology, Ulm University, Ulm, Germany
- German Center for Neurodegenerative Diseases-Ulm (DZNE-Ulm), Ulm, Germany
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12
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Seng C, Luo W, Földy C. Circuit formation in the adult brain. Eur J Neurosci 2022; 56:4187-4213. [PMID: 35724981 PMCID: PMC9546018 DOI: 10.1111/ejn.15742] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 06/08/2022] [Accepted: 06/09/2022] [Indexed: 11/30/2022]
Abstract
Neurons in the mammalian central nervous system display an enormous capacity for circuit formation during development but not later in life. In principle, new circuits could be also formed in adult brain, but the absence of the developmental milieu and the presence of growth inhibition and hundreds of working circuits are generally viewed as unsupportive for such a process. Here, we bring together evidence from different areas of neuroscience—such as neurological disorders, adult‐brain neurogenesis, innate behaviours, cell grafting, and in vivo cell reprogramming—which demonstrates robust circuit formation in adult brain. In some cases, adult‐brain rewiring is ongoing and required for certain types of behaviour and memory, while other cases show significant promise for brain repair in disease models. Together, these examples highlight that the adult brain has higher capacity for structural plasticity than previously recognized. Understanding the underlying mechanisms behind this retained plasticity has the potential to advance basic knowledge regarding the molecular organization of synaptic circuits and could herald a new era of neural circuit engineering for therapeutic repair.
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Affiliation(s)
- Charlotte Seng
- Laboratory of Neural Connectivity, Brain Research Institute, Faculties of Medicine and Science, University of Zurich, Zürich, Switzerland
| | - Wenshu Luo
- Laboratory of Neural Connectivity, Brain Research Institute, Faculties of Medicine and Science, University of Zurich, Zürich, Switzerland
| | - Csaba Földy
- Laboratory of Neural Connectivity, Brain Research Institute, Faculties of Medicine and Science, University of Zurich, Zürich, Switzerland
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13
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Tabuchi A, Ihara D. SRF in Neurochemistry: Overview of Recent Advances in Research on the Nervous System. Neurochem Res 2022; 47:2545-2557. [PMID: 35668335 DOI: 10.1007/s11064-022-03632-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/20/2022] [Accepted: 05/07/2022] [Indexed: 10/18/2022]
Abstract
Serum response factor (SRF) is a representative transcription factor that plays crucial roles in various biological phenomena by regulating immediate early genes (IEGs) and genes related to cell morphology and motility, among others. Over the years, the signal transduction pathways activating SRF have been clarified and SRF-target genes have been identified. In this overview, we initially briefly summarize the basic biology of SRF and its cofactors, ternary complex factor (TCF) and megakaryoblastic leukemia (MKL)/myocardin-related transcription factor (MRTF). Progress in the generation of nervous system-specific knockout (KO) or genetically modified mice as well as genetic analyses over the last few decades has not only identified novel SRF-target genes but also highlighted the neurochemical importance of SRF and its cofactors. Therefore, here we next present the phenotypes of mice with nervous system-specific KO of SRF or its cofactors by depicting recent findings associated with brain development, plasticity, epilepsy, stress response, and drug addiction, all of which result from function or dysfunction of the SRF axis. Last, we develop a hypothesis regarding the possible involvement of SRF and its cofactors in human neurological disorders including neurodegenerative, psychiatric, and neurodevelopmental diseases. This overview should deepen our understanding, highlight promising future directions for developing novel therapeutic strategies, and lead to illumination of the mechanisms underlying higher brain functions based on neuronal structure and function.
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Affiliation(s)
- Akiko Tabuchi
- Laboratory of Molecular Neurobiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan.
| | - Daisuke Ihara
- Laboratory of Molecular Neurobiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
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14
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Whyte-Fagundes P, Taskina D, Safarian N, Zoidl C, Carlen PL, Donaldson LW, Zoidl GR. Panx1 channels promote both anti- and pro-seizure-like activities in the zebrafish via p2rx7 receptors and ATP signaling. Commun Biol 2022; 5:472. [PMID: 35585187 PMCID: PMC9117279 DOI: 10.1038/s42003-022-03356-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 04/12/2022] [Indexed: 11/08/2022] Open
Abstract
The molecular mechanisms of excitation/inhibition imbalances promoting seizure generation in epilepsy patients are not fully understood. Evidence suggests that Pannexin1 (Panx1), an ATP release channel, modulates the excitability of the brain. In this report, we performed electrophysiological, behavioral, and molecular phenotyping experiments on zebrafish larvae bearing genetic or pharmacological knockouts of Panx1a and Panx1b channels, each homologous to human PANX1. When Panx1a function is lost, or both channels are under pharmacological blockade, seizures with ictal-like events and seizure-like locomotion are reduced in the presence of pentylenetetrazol. Transcriptome profiling by RNA-seq demonstrates a spectrum of distinct metabolic and cell signaling states which correlate with the loss of Panx1a. Furthermore, the pro- and anticonvulsant activities of both Panx1 channels affect ATP release and involve the purinergic receptor P2rx7. Our findings suggest a subfunctionalization of Panx1 enabling dual roles in seizures, providing a unique and comprehensive perspective to understanding seizure mechanisms in the context of this channel.
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Affiliation(s)
- Paige Whyte-Fagundes
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada.
- Center of Vision Research (CVR), York University, Toronto, ON, M3J1P3, Canada.
- Krembil Research Institute, University Health Network, 60 Leonard Ave, Toronto, ON, M5T 1M8, Canada.
| | - Daria Taskina
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada
- Center of Vision Research (CVR), York University, Toronto, ON, M3J1P3, Canada
| | - Nickie Safarian
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada
- Center of Vision Research (CVR), York University, Toronto, ON, M3J1P3, Canada
| | - Christiane Zoidl
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada
- Center of Vision Research (CVR), York University, Toronto, ON, M3J1P3, Canada
| | - Peter L Carlen
- Krembil Research Institute, University Health Network, 60 Leonard Ave, Toronto, ON, M5T 1M8, Canada
- Department of Medicine, Physiology and BME, University of Toronto, 399 Bathurst St., 5w442, Toronto, ON, M5T 2S8, Canada
| | | | - Georg R Zoidl
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada.
- Center of Vision Research (CVR), York University, Toronto, ON, M3J1P3, Canada.
- Krembil Research Institute, University Health Network, 60 Leonard Ave, Toronto, ON, M5T 1M8, Canada.
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15
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Time-dependent neuropathology in rats following organophosphate-induced status epilepticus. Neurotoxicology 2022; 91:45-59. [DOI: 10.1016/j.neuro.2022.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 04/11/2022] [Accepted: 04/24/2022] [Indexed: 11/17/2022]
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16
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Wu J, Zhu S, Zhao C, Xu X. Comprehensive investigation of molecular signatures and pathways linking Alzheimer's disease and Epilepsy via bioinformatic approaches. Curr Alzheimer Res 2022; 19:146-160. [PMID: 35114922 DOI: 10.2174/1567205019666220202120638] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/22/2021] [Accepted: 12/03/2022] [Indexed: 11/22/2022]
Abstract
BACKGROUND Epileptic activity is frequent in patients with Alzheimer's disease (AD), and this may accelerate AD progression; however, the relationship between AD and epilepsy remains unclear. OBJECTIVE We aimed to investigate the molecular pathways and genes linking AD and epilepsy using bioinformatics approaches. METHODS Gene expression profiles of AD (GSE1297) and epilepsy (GSE28674) were derived from the Gene Expression Omnibus (GEO) database. The top 50% expression variants were subjected to weighted gene co-expression network analysis (WGCNA) to identify key modules associated with these diseases. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) for the key modules were performed, and the intersected terms of functional enrichment and common genes within the key modules were selected. The overlapping genes were subjected to analyses of protein-protein interaction (PPI) network, transcription factor (TF)-mRNA network, microRNA (miRNA)-mRNA network, and drug prediction. RESULTS We identified 229 and 1187 genes in the AD-associated purple and epilepsy-associated blue modules, respectively. Six shared functional terms between the two modules included "calcium ion binding" and "calcium signaling pathway." According to 17 common genes discovered, 130 TF-mRNA pairs and 56 miRNA-mRNA pairs were established. The topological analyses of the constructed regulatory networks suggested that TF - FOXC1 and miRNA - hsa-mir-335-5p might be vital co-regulators of gene expression in AD and epilepsy. In addition, CXCR4 was identified as a hub gene, becoming the putative target for 20 drugs. CONCLUSION Our study provided novel insights into the molecular connection between AD and epilepsy, which might be beneficial for exploring shared mechanisms and designing disease-modifying therapies.
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Affiliation(s)
- Jiao Wu
- Department of Neurology, the First Hospital of China Medical University, Shenyang, China
- Department of Neurology, The People's Hospital of China Medical University, Shenyang, China
- Department of Neurology, The People's Hospital of Liaoning Province, Shenyang, China
| | - Shu Zhu
- Department of Pediatric Dentistry, School of Stomatology, China Medical University, Shenyang, China
| | - Chenyang Zhao
- Department of Neurology, the First Hospital of China Medical University, Shenyang, China
| | - Xiaoxue Xu
- Department of Neurology, the First Hospital of China Medical University, Shenyang, China
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17
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Martins-Ferreira R, Leal B, Chaves J, Li T, Ciudad L, Rangel R, Santos A, Martins da Silva A, Pinho Costa P, Ballestar E. Epilepsy progression is associated with cumulative DNA methylation changes in inflammatory genes. Prog Neurobiol 2022; 209:102207. [DOI: 10.1016/j.pneurobio.2021.102207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 11/02/2021] [Accepted: 12/14/2021] [Indexed: 01/09/2023]
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18
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Xinghua T, Xiaoxia C, Xinjuan L, Huan C, Jing G, Zhenguo L. The TLR4 mediated inflammatory signal pathway might be involved in drug resistance in drug-resistant epileptic rats. J Neuroimmunol 2022; 365:577802. [DOI: 10.1016/j.jneuroim.2021.577802] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 12/07/2021] [Accepted: 12/26/2021] [Indexed: 02/03/2023]
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19
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Bączyk M, Manuel M, Roselli F, Zytnicki D. From Physiological Properties to Selective Vulnerability of Motor Units in Amyotrophic Lateral Sclerosis. ADVANCES IN NEUROBIOLOGY 2022; 28:375-394. [PMID: 36066833 DOI: 10.1007/978-3-031-07167-6_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Spinal alpha-motoneurons are classified in several types depending on the contractile properties of the innervated muscle fibers. This diversity is further displayed in different levels of vulnerability of distinct motor units to neurodegenerative diseases such as Amyotrophic Lateral Sclerosis (ALS). We summarize recent data suggesting that, contrary to the excitotoxicity hypothesis, the most vulnerable motor units are hypoexcitable and experience a reduction in their firing prior to symptoms onset in ALS. We suggest that a dysregulation of activity-dependent transcriptional programs in these motoneurons alter crucial cellular functions such as mitochondrial biogenesis, autophagy, axonal sprouting capability and re-innervation of neuromuscular junctions.
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Affiliation(s)
- Marcin Bączyk
- Department of Neurobiology, Poznań University of Physical Education, Poznań, Poland
| | - Marin Manuel
- SPPIN - Saints-Pères Paris Institute for the Neurosciences, CNRS, Université de Paris, Paris, France.
| | - Francesco Roselli
- Department of Neurology, Ulm University, Ulm, Germany
- Institute of Anatomy and Cell Biology, Ulm University, Ulm, Germany
- German Center for Neurodegenerative Diseases (DZNE)-Ulm, Ulm, Germany
- Neurozentrum Ulm, Ulm, Germany
| | - Daniel Zytnicki
- SPPIN - Saints-Pères Paris Institute for the Neurosciences, CNRS, Université de Paris, Paris, France
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20
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Tabuchi A, Ihara D. Regulation of Dendritic Synaptic Morphology and Transcription by the SRF Cofactor MKL/MRTF. Front Mol Neurosci 2021; 14:767842. [PMID: 34795561 PMCID: PMC8593110 DOI: 10.3389/fnmol.2021.767842] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 10/11/2021] [Indexed: 12/12/2022] Open
Abstract
Accumulating evidence suggests that the serum response factor (SRF) cofactor megakaryoblastic leukemia (MKL)/myocardin-related transcription factor (MRTF) has critical roles in many physiological and pathological processes in various cell types. MKL/MRTF molecules comprise MKL1/MRTFA and MKL2/MRTFB, which possess actin-binding motifs at the N-terminus, and SRF-binding domains and a transcriptional activation domain (TAD) at the C-terminus. Several studies have reported that, in association with actin rearrangement, MKL/MRTF translocates from the cytoplasm to the nucleus, where it regulates SRF-mediated gene expression and controls cell motility. Therefore, it is important to elucidate the roles of MKL/MRTF in the nervous system with regard to its structural and functional regulation by extracellular stimuli. We demonstrated that MKL/MRTF is highly expressed in the brain, especially the synapses, and is involved in dendritic complexity and dendritic spine maturation. In addition to the positive regulation of dendritic complexity, we identified several MKL/MRTF isoforms that negatively regulate dendritic complexity in cortical neurons. We found that the MKL/MRTF isoforms were expressed differentially during brain development and the impacts of these isoforms on the immediate early genes including Arc/Arg3.1, were different. Here, we review the roles of MKL/MRTF in the nervous system, with a special focus on the MKL/MRTF-mediated fine-tuning of neuronal morphology and gene transcription. In the concluding remarks, we briefly discuss the future perspectives and the possible involvement of MKL/MRTF in neurological disorders such as schizophrenia and autism spectrum disorder.
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Affiliation(s)
- Akiko Tabuchi
- Laboratory of Molecular Neurobiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Daisuke Ihara
- Laboratory of Molecular Neurobiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
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21
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Huang L, Wang J, Liang G, Gao Y, Jin SY, Hu J, Yang X, Lao J, Chen J, Luo ZC, Fan C, Xiong L, Zhu X, Gao TM, Zhong M, Yang X. Upregulated NMDAR-mediated GABAergic transmission underlies autistic-like deficits in Htr3a knockout mice. Am J Cancer Res 2021; 11:9296-9310. [PMID: 34646371 PMCID: PMC8490518 DOI: 10.7150/thno.60531] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 08/28/2021] [Indexed: 11/05/2022] Open
Abstract
Mutations in serotonin pathway genes, especially the serotonergic receptor subunit gene HTR3A, are associated with autism. However, the association of HTR3A deficiency with autism and the underlying mechanisms remain unknown. Methods: The Htr3a knockout (KO) mice were generated using transcription activator-like effector nuclease technology. Various behavior tests, including social interaction, social approach task, olfactory habituation/dishabituation, self-grooming, novel object recognition, contextual fear conditioning, elevated plus maze, open field and seizure susceptibility, were performed to assess the phenotypes. Transcriptome sequencing was carried out to search for molecular network and pathways underlying the phenotypes. Electrophysiological recordings, immunoblotting, immunofluorescence staining, immunoprecipitation, and quantitative real-time PCR were performed to verify the potential mechanisms. The N-methyl-D-aspartate receptor (NMDAR) antagonist memantine was used to treat the KO mice for rescuing the phenotypes. Results: The Htr3a KO mouse model showed three phenotypic domains: autistic-like behaviors (including impaired social behavior, cognitive deficits, and increased repetitive self-grooming), impaired memory, and attenuated susceptibility to pentylenetetrazol-induced seizures. We observed enhanced action potential-driven γ-aminobutyric acid-ergic (GABAergic) transmission in pyramidal neurons and decreased excitatory/inhibitory (E/I) ratio using the patch-clamp recording. Transcriptome sequencing on the hippocampus revealed the converged pathways of the dysregulated molecular networks underlying three phenotypic domains with upregulation of NMDAR. We speculated that Htr3a KO promotes an increase in GABA release through NMDAR upregulation. The electrophysiological recordings on hippocampal parvalbumin-positive (PV+) interneuron revealed increased NMDAR current and NMDAR-dependent excitability. The NMDAR antagonist memantine could rescue GABAergic transmission in the hippocampus and ameliorate autistic-like behaviors of the KO mice. Conclusion: Our data indicated that upregulation of the NMDAR in PV+ interneurons may play a critical role in regulating GABAergic input to pyramidal neurons and maybe involve in the pathogenesis of autism associated with HTR3A deficiency. Therefore, we suggest that the NMDAR system could be considered potential therapeutic target for autism.
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22
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Wilcox JM, Consoli DC, Tienda AA, Dixit S, Buchanan RA, May JM, Nobis WP, Harrison FE. Altered synaptic glutamate homeostasis contributes to cognitive decline in young APP/PSEN1 mice. Neurobiol Dis 2021; 158:105486. [PMID: 34450329 PMCID: PMC8457528 DOI: 10.1016/j.nbd.2021.105486] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 08/10/2021] [Accepted: 08/16/2021] [Indexed: 12/02/2022] Open
Abstract
Non-convulsive epileptiform activity is a common and under-studied comorbidity of Alzheimer’s disease that may significantly contribute to onset of clinical symptoms independently of other neuropathological features such as β-amyloid deposition. We used repeated treatment with low dose kainic acid (KA) to trigger subthreshold epileptiform activity in young (less than 6 months) wild-type (WT) and APP/PSEN1 mice to test the role of disruption to the glutamatergic system in epileptiform activity changes and the development of memory deficits. Short-term repeated low-dose KA (five daily treatments with 5 mg/kg, IP) impaired long-term potentiation in hippocampus of APP/PSEN1 but not WT mice. Long-term repeated low-dose KA (fourteen weeks of bi-weekly treatment with 7.5–10 mg/kg) led to high mortality in APP/PSEN1 mice. KA treatment also impaired memory retention in the APP/PSEN1 mice in a Morris water maze task under cognitively challenging reversal learning conditions where the platform was moved to a new location. Four weeks of bi-weekly treatment with 5 mg/kg KA also increased abnormal spike activity in APP/PSEN1 and not WT mice but did not impact sleep/wake behavioral states. These findings suggest that hyperexcitability in Alzheimer’s disease may indeed be an early contributor to cognitive decline that is independent of heavy β-amyloid-plaque load, which is absent in APP/PSEN1 mice under 6 months of age.
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Affiliation(s)
- J M Wilcox
- Program in Neuroscience, Vanderbilt University, Nashville, TN, United States of America; Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - D C Consoli
- Program in Neuroscience, Vanderbilt University, Nashville, TN, United States of America
| | - A A Tienda
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - S Dixit
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - R A Buchanan
- Program in Neuroscience, Vanderbilt University, Nashville, TN, United States of America
| | - J M May
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - W P Nobis
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - F E Harrison
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States of America.
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23
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Cao Q, Yang F, Wang H. CB2R induces a protective response against epileptic seizures through ERK and p38 signaling pathways. Int J Neurosci 2021; 131:735-744. [PMID: 32715907 DOI: 10.1080/00207454.2020.1796661] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 05/09/2020] [Accepted: 07/01/2020] [Indexed: 01/07/2023]
Abstract
BACKGROUND AND PURPOSE Epilepsy is a pivotal neurological disorder characterized by the synchronous discharging of neurons to induce momentary brain dysfunction. Temporal lobe epilepsy is the most common type of epilepsy, with seizures originating from the mesial temporal lobe. The hippocampus forms part of the mesial temporal lobe and plays a significant role in epileptogenesis; it also has a vital influence on the mental development of children. In this study, we aimed to explore the effects of CB2 receptor (CB2R) activation on ERK and p38 signaling in nerve cells of a rat epilepsy model. MATERIALS AND METHODS We treated Sprague-Dawley rats with pilocarpine to induce an epilepsy model and treated such animals with a CB2R agonist (JWH133) alone or with a CB2R antagonist (AM630). Nissl's stain showed the neuron conditon in different groups. Western blot analyzed the level of p-ERK and p-p38. RESULTS JWH133 can increase the latent period of first seizure attack and decrease the Grades IV-V magnitude ratio after the termination of SE. Nissl's stain showed JWH133 protected neurons in the hippocampus while AM630 inhibited the functioning of CB2R in neurons. Western blot analysis showed that JWH133 decreased levels of p-ERK and p-p38, which is found at increased levels in the hippocampus of our epilepsy model. In contrast, AM630 inhibited the protective function of JWH133 and also enhanced levels of p-ERK and p-p38. CONCLUSIONS CB2R activation can induce neurons proliferation and survival through activation of ERK and p38 signaling pathways.
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Affiliation(s)
- Qingjun Cao
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China
| | - Fenghua Yang
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China
| | - Hua Wang
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China
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Multi-omics in mesial temporal lobe epilepsy with hippocampal sclerosis: Clues into the underlying mechanisms leading to disease. Seizure 2021; 90:34-50. [DOI: 10.1016/j.seizure.2021.03.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 02/26/2021] [Accepted: 03/02/2021] [Indexed: 02/07/2023] Open
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25
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Shinohara M, Kikuchi M, Onishi-Takeya M, Tashiro Y, Suzuki K, Noda Y, Takeda S, Mukouzono M, Nagano S, Fukumori A, Morishita R, Nakaya A, Sato N. Upregulated expression of a subset of genes in APP; ob/ ob mice: Evidence of an interaction between diabetes-linked obesity and Alzheimer's disease. FASEB Bioadv 2021; 3:323-333. [PMID: 33977233 PMCID: PMC8103720 DOI: 10.1096/fba.2020-00151] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/17/2021] [Accepted: 01/29/2021] [Indexed: 12/26/2022] Open
Abstract
Clinical studies have indicated that obesity and diabetes are associated with Alzheimer's disease (AD) and neurodegeneration. However, the mechanism by which obesity/diabetes and AD interact with each other and contribute to dementia remains elusive. To obtain insights into their interaction at molecular levels, we performed gene expression analysis of APP;ob/ob mice, which were generated by crossing transgenic AD model mice (APP23 mice) with ob/ob mice, which are obese and mildly diabetic. The Aβ level in these mice was reduced compared with that in pure APP mice. However, we identified a cluster of genes (cluster 10) upregulated in APP;ob/ob mice but not in either APP or ob/ob mice. Interestingly, genes upregulated in the human AD brain were enriched in cluster 10. Moreover, genes in cluster 10 formed a network and shared upregulated genes with a cell model of neurodegeneration and other models of neurological disorders such as ischemia and epilepsy. In silico analyses showed that serum response factor (SRF), recently identified in a single-cell analysis of human brains as a transcription factor that can control the conversion from healthy cells to AD cells, might be a common transcriptional regulator for a subset of cluster 10 genes. These data suggest that upregulation of genes uniquely associated with APP;ob/ob mice is an evidence of the interaction between obesity/diabetes and AD.
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Affiliation(s)
- Mitsuru Shinohara
- Department of Aging Neurobiology Center for Development of Advanced Medicine for Dementia National Center for Geriatrics and Gerontology Obu Aichi Japan.,Department of Aging Neurobiology Graduate School of Medicine Osaka University Osaka Japan
| | - Masataka Kikuchi
- Department of Genome Informatics Graduate School of Medicine Osaka University Osaka Japan
| | - Miyuki Onishi-Takeya
- Department of Geriatric Medicine Graduate School of Medicine Osaka University Osaka Japan
| | - Yoshitaka Tashiro
- Department of Aging Neurobiology Center for Development of Advanced Medicine for Dementia National Center for Geriatrics and Gerontology Obu Aichi Japan
| | - Kaoru Suzuki
- Department of Aging Neurobiology Center for Development of Advanced Medicine for Dementia National Center for Geriatrics and Gerontology Obu Aichi Japan
| | - Yasuhiro Noda
- Department of Aging Neurobiology Center for Development of Advanced Medicine for Dementia National Center for Geriatrics and Gerontology Obu Aichi Japan
| | - Shuko Takeda
- Department of Clinical Gene Therapy Graduate School of Medicine Osaka University Osaka Japan
| | - Masahiro Mukouzono
- Department of Clinical Gene Therapy Graduate School of Medicine Osaka University Osaka Japan
| | - Seiichi Nagano
- Department of Neurology Graduate School of Medicine Osaka University Osaka Japan
| | - Akio Fukumori
- Department of Aging Neurobiology Center for Development of Advanced Medicine for Dementia National Center for Geriatrics and Gerontology Obu Aichi Japan.,Department of Aging Neurobiology Graduate School of Medicine Osaka University Osaka Japan
| | - Ryuichi Morishita
- Department of Clinical Gene Therapy Graduate School of Medicine Osaka University Osaka Japan
| | - Akihiro Nakaya
- Department of Genome Informatics Graduate School of Medicine Osaka University Osaka Japan
| | - Naoyuki Sato
- Department of Aging Neurobiology Center for Development of Advanced Medicine for Dementia National Center for Geriatrics and Gerontology Obu Aichi Japan.,Department of Aging Neurobiology Graduate School of Medicine Osaka University Osaka Japan
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26
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Kumar S, Attrish D, Srivastava A, Banerjee J, Tripathi M, Chandra PS, Dixit AB. Non-histone substrates of histone deacetylases as potential therapeutic targets in epilepsy. Expert Opin Ther Targets 2020; 25:75-85. [PMID: 33275850 DOI: 10.1080/14728222.2021.1860016] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Introduction: Epilepsy is a network-level neurological disorder characterized by unprovoked recurrent seizures and associated comorbidities. Aberrant activity and localization of histone deacetylases (HDACs) have been reported in epilepsy and HDAC inhibitors (HDACi) have been used for therapeutic purposes. Several non-histone targets of HDACs have been recognized whose reversible acetylation can modulate protein functions and can contribute to disease pathology. Areas covered: This review provides an overview of HDACs in epilepsy and reflects its action on non-histone substrates involved in the pathogenesis of epilepsy and explores the effectiveness of HDACi as anti-epileptic drugs (AEDs). It also covers the efforts undertaken to target the interaction of HDACs with their substrates. We have further discussed non-deacetylase activity possessed by specific HDACs that might be essential in unraveling the molecular mechanism underlying the disease. For this purpose, relevant literature from 1996 to 2020 was derived from PubMed. Expert opinion: The interaction of HDACs and their non-histone substrates can serve as a promising therapeutic target for epilepsy. Pan-HDACi offers limited benefits to the epileptic patients. Thus, identification of novel targets of HDACs contributing to the disease and designing inhibitors targeting these complexes would be more effective and holds a greater potential as an anti-epileptogenic therapy.
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Affiliation(s)
- Sonali Kumar
- Dr. B.R. Ambedkar Centre for Biomedical Research (ACBR), University of Delhi , New Delhi, India
| | - Diksha Attrish
- Dr. B.R. Ambedkar Centre for Biomedical Research (ACBR), University of Delhi , New Delhi, India
| | | | | | | | | | - Aparna Banerjee Dixit
- Dr. B.R. Ambedkar Centre for Biomedical Research (ACBR), University of Delhi , New Delhi, India
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27
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Tiwari D, Schaefer TL, Schroeder-Carter LM, Krzeski JC, Bunk AT, Parkins EV, Snider A, Danzer R, Williams MT, Vorhees CV, Danzer SC, Gross C. The potassium channel Kv4.2 regulates dendritic spine morphology, electroencephalographic characteristics and seizure susceptibility in mice. Exp Neurol 2020; 334:113437. [PMID: 32822706 PMCID: PMC7642025 DOI: 10.1016/j.expneurol.2020.113437] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 08/13/2020] [Accepted: 08/17/2020] [Indexed: 01/21/2023]
Abstract
The voltage-gated potassium channel Kv4.2 is a critical regulator of dendritic excitability in the hippocampus and is crucial for dendritic signal integration. Kv4.2 mRNA and protein expression as well as function are reduced in several genetic and pharmacologically induced rodent models of epilepsy and autism. It is not known, however, whether reduced Kv4.2 is just an epiphenomenon or a disease-contributing cause of neuronal hyperexcitability and behavioral impairments in these neurological disorders. To address this question, we used male and female mice heterozygous for a Kv.2 deletion and adult-onset manipulation of hippocampal Kv4.2 expression in male mice to assess the role of Kv4.2 in regulating neuronal network excitability, morphology and anxiety-related behaviors. We observed a reduction in dendritic spine density and reduced proportions of thin and stubby spines but no changes in anxiety, overall activity, or retention of conditioned freezing memory in Kv4.2 heterozygous mice compared with wildtype littermates. Using EEG analyses, we showed elevated theta power and increased spike frequency in Kv4.2 heterozygous mice under basal conditions. In addition, the latency to onset of kainic acid-induced seizures was significantly shortened in Kv4.2 heterozygous mice compared with wildtype littermates, which was accompanied by a significant increase in theta power. By contrast, overexpressing Kv4.2 in wildtype mice through intrahippocampal injection of Kv4.2-expressing lentivirus delayed seizure onset and reduced EEG power. These results suggest that Kv4.2 is an important regulator of neuronal network excitability and dendritic spine morphology, but not anxiety-related behaviors. In the future, manipulation of Kv4.2 expression could be used to alter seizure susceptibility in epilepsy.
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Affiliation(s)
- Durgesh Tiwari
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Tori L Schaefer
- Division of Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | | | - Joseph C Krzeski
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Alexander T Bunk
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Emma V Parkins
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Andrew Snider
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Reese Danzer
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Michael T Williams
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Charles V Vorhees
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Steve C Danzer
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA; Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Christina Gross
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA.
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28
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Longueville S, Nakamura Y, Brami-Cherrier K, Coura R, Hervé D, Girault JA. Long-lasting tagging of neurons activated by seizures or cocaine administration in Egr1-CreER T2 transgenic mice. Eur J Neurosci 2020; 53:1450-1472. [PMID: 33226686 DOI: 10.1111/ejn.15060] [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: 10/13/2020] [Revised: 11/17/2020] [Accepted: 11/19/2020] [Indexed: 11/29/2022]
Abstract
Permanent tagging of neuronal ensembles activated in specific experimental situations is an important objective to study their properties and adaptations. In the context of learning and memory, these neurons are referred to as engram neurons. Here, we describe and characterize a novel mouse line, Egr1-CreERT2 , which carries a transgene in which the promoter of the immediate early gene Egr1 drives the expression of the CreERT2 recombinase that is only active in the presence of tamoxifen metabolite, 4-hydroxy-tamoxifen (4-OHT). Egr1-CreERT2 mice were crossed with various reporter mice, Cre-dependently expressing a fluorescent protein. Without tamoxifen or 4-OHT, no or few tagged neurons were observed. Epileptic seizures induced by pilocarpine or pentylenetetrazol in the presence of tamoxifen or 4-OHT elicited the persistent tagging of many neurons and some astrocytes in the dentate gyrus of hippocampus, where Egr1 is transiently induced by seizures. One week after cocaine and 4-OHT administration, these mice displayed a higher number of tagged neurons in the dorsal striatum than saline/4-OHT controls, with differences between reporter lines. Cocaine-induced tagging required ERK activation and tagged neurons were more likely than others to exhibit ERK phosphorylation or Fos induction after a second injection. Interestingly neurons tagged in saline-treated mice also had an increased propensity to express Fos, suggesting the existence of highly responsive striatal neurons susceptible to be re-activated by cocaine repeated administration, which may contribute to the behavioral adaptations. Our report validates a novel transgenic mouse model for permanently tagging activated neurons and studying long-term alterations of Egr1-expressing cells.
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Affiliation(s)
- Sophie Longueville
- Inserm UMR-S 1270, Paris, France.,Sciences and Engineering Faculty, Sorbonne Université, Paris, France.,Institut du Fer à Moulin, Paris, France
| | - Yuki Nakamura
- Inserm UMR-S 1270, Paris, France.,Sciences and Engineering Faculty, Sorbonne Université, Paris, France.,Institut du Fer à Moulin, Paris, France
| | - Karen Brami-Cherrier
- Inserm UMR-S 1270, Paris, France.,Sciences and Engineering Faculty, Sorbonne Université, Paris, France.,Institut du Fer à Moulin, Paris, France
| | - Renata Coura
- Inserm UMR-S 1270, Paris, France.,Sciences and Engineering Faculty, Sorbonne Université, Paris, France.,Institut du Fer à Moulin, Paris, France
| | - Denis Hervé
- Inserm UMR-S 1270, Paris, France.,Sciences and Engineering Faculty, Sorbonne Université, Paris, France.,Institut du Fer à Moulin, Paris, France
| | - Jean-Antoine Girault
- Inserm UMR-S 1270, Paris, France.,Sciences and Engineering Faculty, Sorbonne Université, Paris, France.,Institut du Fer à Moulin, Paris, France
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29
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Denkena J, Zaisser A, Merz B, Klinger B, Kuhl D, Blüthgen N, Hermey G. Neuronal activity regulates alternative exon usage. Mol Brain 2020; 13:148. [PMID: 33172478 PMCID: PMC7656758 DOI: 10.1186/s13041-020-00685-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 10/09/2020] [Indexed: 01/18/2023] Open
Abstract
Neuronal activity-regulated gene transcription underlies plasticity-dependent changes in the molecular composition and structure of neurons. A large number of genes regulated by different neuronal plasticity inducing pathways have been identified, but altered gene expression levels represent only part of the complexity of the activity-regulated transcriptional program. Alternative splicing, the differential inclusion and exclusion of exonic sequence in mRNA, is an additional mechanism that is thought to define the activity-dependent transcriptome. Here, we present a genome wide microarray-based survey to identify exons with increased expression levels at 1, 4 or 8 h following neuronal activity in the murine hippocampus provoked by generalized seizures. We used two different bioinformatics approaches to identify alternative activity-induced exon usage and to predict alternative splicing, ANOSVA (ANalysis Of Splicing VAriation) which we here adjusted to accommodate data from different time points and FIRMA (Finding Isoforms using Robust Multichip Analysis). RNA sequencing, in situ hybridization and reverse transcription PCR validate selected activity-dependent splicing events of previously described and so far undescribed activity-regulated transcripts, including Homer1a, Homer1d, Ania3, Errfi1, Inhba, Dclk1, Rcan1, Cda, Tpm1 and Krt75. Taken together, our survey significantly adds to the comprehensive understanding of the complex activity-dependent neuronal transcriptomic signature. In addition, we provide data sets that will serve as rich resources for future comparative expression analyses.
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Affiliation(s)
- Johanna Denkena
- Institute for Theoretical Biology and Institute of Pathology, Charité-Universitätsmedizin Berlin, Berlin, 10117, Germany.,Integrative Research Institute Life Sciences, Humboldt Universität Berlin, 10115, Berlin, Germany
| | - Andrea Zaisser
- Institute for Molecular and Cellular Cognition, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251, Hamburg, Germany
| | - Barbara Merz
- Institute for Molecular and Cellular Cognition, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251, Hamburg, Germany
| | - Bertram Klinger
- Institute for Theoretical Biology and Institute of Pathology, Charité-Universitätsmedizin Berlin, Berlin, 10117, Germany.,Integrative Research Institute Life Sciences, Humboldt Universität Berlin, 10115, Berlin, Germany
| | - Dietmar Kuhl
- Institute for Molecular and Cellular Cognition, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251, Hamburg, Germany
| | - Nils Blüthgen
- Institute for Theoretical Biology and Institute of Pathology, Charité-Universitätsmedizin Berlin, Berlin, 10117, Germany.,Integrative Research Institute Life Sciences, Humboldt Universität Berlin, 10115, Berlin, Germany
| | - Guido Hermey
- Institute for Molecular and Cellular Cognition, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251, Hamburg, Germany.
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30
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Brenet A, Somkhit J, Hassan-Abdi R, Yanicostas C, Romain C, Bar O, Igert A, Saurat D, Taudon N, Dal-Bo G, Nachon F, Dupuis N, Soussi-Yanicostas N. Organophosphorus diisopropylfluorophosphate (DFP) intoxication in zebrafish larvae causes behavioral defects, neuronal hyperexcitation and neuronal death. Sci Rep 2020; 10:19228. [PMID: 33154418 PMCID: PMC7645799 DOI: 10.1038/s41598-020-76056-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 10/19/2020] [Indexed: 11/09/2022] Open
Abstract
With millions of intoxications each year and over 200,000 deaths, organophosphorus (OP) compounds are an important public health issue worldwide. OP poisoning induces cholinergic syndrome, with respiratory distress, hypertension, and neuron damage that may lead to epileptic seizures and permanent cognitive deficits. Existing countermeasures are lifesaving but do not prevent long-lasting neuronal comorbidities, emphasizing the urgent need for animal models to better understand OP neurotoxicity and identify novel antidotes. Here, using diisopropylfluorophosphate (DFP), a prototypic and moderately toxic OP, combined with zebrafish larvae, we first showed that DFP poisoning caused major acetylcholinesterase inhibition, resulting in paralysis and CNS neuron hyperactivation, as indicated by increased neuronal calcium transients and overexpression of the immediate early genes fosab, junBa, npas4b, and atf3. In addition to these epileptiform seizure-like events, DFP-exposed larvae showed increased neuronal apoptosis, which were both partially alleviated by diazepam treatment, suggesting a causal link between neuronal hyperexcitation and cell death. Last, DFP poisoning induced an altered balance of glutamatergic/GABAergic synaptic activity with increased NR2B-NMDA receptor accumulation combined with decreased GAD65/67 and gephyrin protein accumulation. The zebrafish DFP model presented here thus provides important novel insights into the pathophysiology of OP intoxication, making it a promising model to identify novel antidotes.
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Affiliation(s)
| | - Julie Somkhit
- NeuroDiderot, Inserm, Université de Paris, 75019, Paris, France
| | | | | | | | - Olivier Bar
- NeuroDiderot, Inserm, Université de Paris, 75019, Paris, France
| | - Alexandre Igert
- Département de toxicologie et risques chimiques, Institut de Recherche Biomédicale des Armées (IRBA), 91 220, Brétigny-sur-Orge, France
| | - Dominique Saurat
- Institut de Recherche Biomédicale des Armées (IRBA), Unité de Développements Analytiques et Bioanalyse, 91 220, Brétigny-sur-Orge, France
| | - Nicolas Taudon
- Institut de Recherche Biomédicale des Armées (IRBA), Unité de Développements Analytiques et Bioanalyse, 91 220, Brétigny-sur-Orge, France
| | - Gregory Dal-Bo
- Département de toxicologie et risques chimiques, Institut de Recherche Biomédicale des Armées (IRBA), 91 220, Brétigny-sur-Orge, France
| | - Florian Nachon
- Département de toxicologie et risques chimiques, Institut de Recherche Biomédicale des Armées (IRBA), 91 220, Brétigny-sur-Orge, France
| | - Nina Dupuis
- Département de toxicologie et risques chimiques, Institut de Recherche Biomédicale des Armées (IRBA), 91 220, Brétigny-sur-Orge, France
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31
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Functional Genomics of Epileptogenesis in Animal Models and Humans. Cell Mol Neurobiol 2020; 41:1579-1587. [PMID: 32725455 DOI: 10.1007/s10571-020-00927-x] [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: 12/03/2019] [Accepted: 07/20/2020] [Indexed: 12/14/2022]
Abstract
It has been estimated that epilepsies are among the top five neurological diseases with the highest burden of disease. In recent years, genome-wide expression studies (GWES) have been carried out in experimental models of epilepsy and in samples from human patients. In this study, I carried out meta-analyses and analyses of convergence for available GWES for epileptogenesis in humans and in mouse, rat, zebrafish and fruit fly models. Multiple lines of evidence (such as genome-wide association data and known druggable genes) were integrated to prioritize top candidate genes for epileptogenesis and a functional enrichment analysis was carried out. Several top candidate genes, which are supported by multiple lines of genomic evidence, such as GRIN1, KCNAB1 and STX1B, were identified. Druggable genes of potential interest (such as GABRA2, GRIK1, KCNAB1 and STX4) were also identified. An enrichment of genes regulated by the MEF2 and SOX5 transcription factors and the miR-106b-5p and miR-101-3p miRNAs was found. The current work is the first meta-analysis and convergent analysis of GWES for epileptogenesis in humans and in multiple animal models, integrating results from several genomic studies. Novel candidate genes and pathways for epileptogenesis were identified in this analysis.
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Díaz-Rodríguez SM, López-López D, Herrero-Turrión MJ, Gómez-Nieto R, Canal-Alonso A, Lopéz DE. Inferior Colliculus Transcriptome After Status Epilepticus in the Genetically Audiogenic Seizure-Prone Hamster GASH/Sal. Front Neurosci 2020; 14:508. [PMID: 32528245 PMCID: PMC7264424 DOI: 10.3389/fnins.2020.00508] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 04/22/2020] [Indexed: 01/31/2023] Open
Abstract
The Genetic Audiogenic Seizure Hamster from Salamanca (GASH/Sal), an animal model of reflex epilepsy, exhibits generalized tonic–clonic seizures in response to loud sound with the epileptogenic focus localized in the inferior colliculus (IC). Ictal events in seizure-prone strains cause gene deregulation in the epileptogenic focus, which can provide insights into the epileptogenic mechanisms. Thus, the present study aimed to determine the expression profile of key genes in the IC of the GASH/Sal after the status epilepticus. For such purpose, we used RNA-Seq to perform a comparative study between the IC transcriptome of GASH/Sal and that of control hamsters both subjected to loud sound stimulation. After filtering for normalization and gene selection, a total of 36 genes were declared differentially expressed from the RNA-seq analysis in the IC. A set of differentially expressed genes were validated by RT-qPCR showing significant differentially expression between GASH/Sal hamsters and Syrian control hamsters. The confirmed differentially expressed genes were classified on ontological categories associated with epileptogenic events similar to those produced by generalized tonic seizures in humans. Subsequently, based on the result of metabolomics, we found the interleukin-4 and 13-signaling, and nucleoside transport as presumably altered routes in the GASH/Sal model. This research suggests that seizures in GASH/Sal hamsters are generated by multiple molecular substrates, which activate biological processes, molecular processes, cellular components and metabolic pathways associated with epileptogenic events similar to those produced by tonic seizures in humans. Therefore, our study supports the use of the GASH/Sal as a valuable animal model for epilepsy research, toward establishing correlations with human epilepsy and searching new biomarkers of epileptogenesis.
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Affiliation(s)
- Sandra M Díaz-Rodríguez
- Institute of Neurosciences of Castilla y León, University of Salamanca, Salamanca, Spain.,Institute of Biomedical Research of Salamanca, University of Salamanca, Salamanca, Spain.,Department of Cellular Biology and Pathology, University of Salamanca, Salamanca, Spain
| | - Daniel López-López
- Institute of Neurosciences of Castilla y León, University of Salamanca, Salamanca, Spain
| | - Manuel J Herrero-Turrión
- Institute of Neurosciences of Castilla y León, University of Salamanca, Salamanca, Spain.,Institute of Biomedical Research of Salamanca, University of Salamanca, Salamanca, Spain.,Neurological Tissue Bank INCYL (BTN-INCYL), Salamanca, Spain
| | - Ricardo Gómez-Nieto
- Institute of Neurosciences of Castilla y León, University of Salamanca, Salamanca, Spain.,Institute of Biomedical Research of Salamanca, University of Salamanca, Salamanca, Spain.,Department of Cellular Biology and Pathology, University of Salamanca, Salamanca, Spain
| | - Angel Canal-Alonso
- Institute of Biomedical Research of Salamanca, University of Salamanca, Salamanca, Spain.,BISITE Research Group, University of Salamanca, Salamanca, Spain
| | - Dolores E Lopéz
- Institute of Neurosciences of Castilla y León, University of Salamanca, Salamanca, Spain.,Institute of Biomedical Research of Salamanca, University of Salamanca, Salamanca, Spain.,Department of Cellular Biology and Pathology, University of Salamanca, Salamanca, Spain
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33
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Förstner P, Knöll B. Interference of neuronal activity-mediated gene expression through serum response factor deletion enhances mortality and hyperactivity after traumatic brain injury. FASEB J 2020; 34:3855-3873. [PMID: 31930559 DOI: 10.1096/fj.201902257rr] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 12/19/2019] [Accepted: 12/23/2019] [Indexed: 12/31/2022]
Abstract
Traumatic brain injury (TBI) is one of the most frequent causes of brain injury and mortality in young adults with detrimental sequelae such as cognitive impairments, epilepsy, and attention-deficit hyperactivity disorder. TBI modulates the neuronal excitability resulting in propagation of a neuronal activity-driven gene expression program. However, the impact of such neuronal activity mediated gene expression in TBI has been poorly studied. In this study we analyzed mouse mutants of the prototypical neuronal activity-dependent transcription factor SRF (serum response factor) in a weight-drop TBI model. Neuron-restricted SRF deletion elevated TBI inflicted mortality suggesting a neuroprotective SRF function during TBI. Behavioral inspection uncovered elevated locomotor activity in Srf mutant mice after TBI in contrast to hypoactivity observed in wild-type littermates. This indicates an SRF role in modulation of TBI-associated alterations in locomotor activity. Finally, induction of a neuronal activity induced gene expression program composed of immediate early genes (IEGs) such as Egr1, Egr2, Egr3, Npas4, Atf3, Arc, Ptgs2, and neuronal pentraxins (Nptx2) was compromised upon SRF depletion. Overall, our data show a role of neuronal activity-mediated gene transcription during TBI and suggest a molecular link between TBI and such post-TBI neurological comorbidities involving hyperactivity phenotypes.
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Affiliation(s)
- Philip Förstner
- Institute of Physiological Chemistry, Ulm University, Ulm, Germany
| | - Bernd Knöll
- Institute of Physiological Chemistry, Ulm University, Ulm, Germany
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34
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Tyssowski KM, Letai KC, Rendall SD, Tan C, Nizhnik A, Kaeser PS, Gray JM. Firing Rate Homeostasis Can Occur in the Absence of Neuronal Activity-Regulated Transcription. J Neurosci 2019; 39:9885-9899. [PMID: 31672790 PMCID: PMC6978944 DOI: 10.1523/jneurosci.1108-19.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 09/27/2019] [Accepted: 10/18/2019] [Indexed: 01/06/2023] Open
Abstract
Despite dynamic inputs, neuronal circuits maintain relatively stable firing rates over long periods. This maintenance of firing rate, or firing rate homeostasis, is likely mediated by homeostatic mechanisms such as synaptic scaling and regulation of intrinsic excitability. Because some of these homeostatic mechanisms depend on transcription of activity-regulated genes, including Arc and Homer1a, we hypothesized that activity-regulated transcription would be required for firing rate homeostasis. Surprisingly, however, we found that cultured mouse cortical neurons from both sexes grown on multi-electrode arrays homeostatically adapt their firing rates to persistent pharmacological stimulation even when activity-regulated transcription is disrupted. Specifically, we observed firing rate homeostasis in Arc knock-out neurons, as well as knock-out neurons lacking the activity-regulated transcription factors AP1 and SRF. Firing rate homeostasis also occurred normally during acute pharmacological blockade of transcription. Thus, firing rate homeostasis in response to increased neuronal activity can occur in the absence of neuronal-activity-regulated transcription.SIGNIFICANCE STATEMENT Neuronal circuits maintain relatively stable firing rates even in the face of dynamic circuit inputs. Understanding the molecular mechanisms that enable this firing rate homeostasis could potentially provide insight into neuronal diseases that present with an imbalance of excitation and inhibition. It has long been proposed that activity-regulated transcription could underlie firing rate homeostasis because activity-regulated genes turn on when neurons are above their target firing rates and include many genes that could regulate firing rate. Surprisingly, despite this prediction, we found that cortical neurons can undergo firing rate homeostasis in the absence of activity-regulated transcription, indicating that firing rate homeostasis can be controlled by non-transcriptional mechanisms.
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Affiliation(s)
| | | | | | - Chao Tan
- Neurobiology, Harvard Medical School, Boston, Massachusetts 02115
| | | | - Pascal S Kaeser
- Neurobiology, Harvard Medical School, Boston, Massachusetts 02115
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Tyssowski KM, Gray JM. The neuronal stimulation-transcription coupling map. Curr Opin Neurobiol 2019; 59:87-94. [PMID: 31163285 PMCID: PMC6885097 DOI: 10.1016/j.conb.2019.05.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 05/06/2019] [Indexed: 12/17/2022]
Abstract
Neurons transcribe different genes in response to different extracellular stimuli, and these genes regulate neuronal plasticity. Thus, understanding how different stimuli regulate different stimulus-dependent gene modules would deepen our understanding of plasticity. To systematically dissect the coupling between stimulation and transcription, we propose creating a 'stimulation-transcription coupling map' that describes the transcription response to each possible extracellular stimulus. While we are currently far from having a complete map, recent genomic experiments have begun to facilitate its creation. Here, we describe the current state of the stimulation-transcription coupling map as well as the transcriptional regulation that enables this coupling.
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Affiliation(s)
- Kelsey M Tyssowski
- Harvard Medical School, Department of Genetics, 77 Ave Louis Pasteur, Boston, MA 02115, United States
| | - Jesse M Gray
- Harvard Medical School, Department of Genetics, 77 Ave Louis Pasteur, Boston, MA 02115, United States.
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Hammer MF, Sprissler R, Bina RW, Lau B, Johnstone L, Walter CM, Labiner DM, Weinand ME. Altered expression of signaling pathways regulating neuronal excitability in hippocampal tissue of temporal lobe epilepsy patients with low and high seizure frequency. Epilepsy Res 2019; 155:106145. [DOI: 10.1016/j.eplepsyres.2019.05.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 05/17/2019] [Accepted: 05/23/2019] [Indexed: 12/22/2022]
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Loss of serum response factor in mature neurons in the dentate gyrus alters the morphology of dendritic spines and hippocampus-dependent behavioral tasks. Brain Struct Funct 2019; 224:2691-2701. [PMID: 31375980 PMCID: PMC6778544 DOI: 10.1007/s00429-019-01925-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 07/19/2019] [Indexed: 12/12/2022]
Abstract
Serum response factor (SRF) is a major transcription factor that regulates the expression of several plasticity-associated genes in the brain. Although the developmental expression of SRF in excitatory neurons is crucial for establishing proper hippocampal circuitry, no substantial evidence of its role in unstimulated mature neurons has been provided. The present study used time-controlled, conditional SRF knockout mice and found that the lack of SRF in adult neurons led to decreased actin levels and inactivation of the actin-severing protein cofilin 1 through its increase in phosphorylation at Ser3. The augmentation of cofilin 1 phosphorylation correlated with an alteration of dendritic spine morphology in the dentate gyrus, which was reflected by an increase in the number of spines that clustered into the long-spine category. The changes in spine morphology coincided with a lower amplitude and frequency of miniature excitatory postsynaptic currents. Moreover, SRF knockout animals were hyperactive and exhibited impairments in hippocampus-dependent behaviors, such as digging, marble burying, and nesting. Altogether, our data indicate that the adult deletion of neuronal SRF leads to alterations of spine morphology and function and hippocampus-dependent behaviors. Thus, SRF deletion in adult neurons recapitulates some aspects of morphological, electrophysiological, and behavioral changes that are observed in such psychiatric disorders as schizophrenia and autism spectrum disorders.
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Tiwari D, Brager DH, Rymer JK, Bunk AT, White AR, Elsayed NA, Krzeski JC, Snider A, Schroeder Carter LM, Danzer SC, Gross C. MicroRNA inhibition upregulates hippocampal A-type potassium current and reduces seizure frequency in a mouse model of epilepsy. Neurobiol Dis 2019; 130:104508. [PMID: 31212067 DOI: 10.1016/j.nbd.2019.104508] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 06/12/2019] [Accepted: 06/13/2019] [Indexed: 12/13/2022] Open
Abstract
Epilepsy is often associated with altered expression or function of ion channels. One example of such a channelopathy is the reduction of A-type potassium currents in the hippocampal CA1 region. The underlying mechanisms of reduced A-type channel function in epilepsy are unclear. Here, we show that inhibiting a single microRNA, miR-324-5p, which targets the pore-forming A-type potassium channel subunit Kv4.2, selectively increased A-type potassium currents in hippocampal CA1 pyramidal neurons in mice. Resting membrane potential, input resistance and other potassium currents were not altered. In a mouse model of acquired chronic epilepsy, inhibition of miR-324-5p reduced the frequency of spontaneous seizures and interictal epileptiform spikes supporting the physiological relevance of miR-324-5p-mediated control of A-type currents in regulating neuronal excitability. Mechanistic analyses demonstrated that microRNA-induced silencing of Kv4.2 mRNA is increased in epileptic mice leading to reduced Kv4.2 protein levels, which is mitigated by miR-324-5p inhibition. By contrast, other targets of miR-324-5p were unchanged. These results suggest a selective miR-324-5p-dependent mechanism in epilepsy regulating potassium channel function, hyperexcitability and seizures.
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Affiliation(s)
- Durgesh Tiwari
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Darrin H Brager
- Center for Learning and Memory, Department of Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA
| | - Jeffrey K Rymer
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Alexander T Bunk
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Angela R White
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Nada A Elsayed
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Joseph C Krzeski
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Andrew Snider
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | | | - Steve C Danzer
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Anesthesia, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Christina Gross
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA.
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Deng J, Xu T, Yang J, Zhang KM, Li Q, Yu XY, Li R, Fu J, Jiang Q, Ma JX, Chen YM. Sema7A, a brain immune regulator, regulates seizure activity in PTZ-kindled epileptic rats. CNS Neurosci Ther 2019; 26:101-116. [PMID: 31179640 PMCID: PMC6930824 DOI: 10.1111/cns.13181] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/15/2019] [Accepted: 05/21/2019] [Indexed: 12/11/2022] Open
Abstract
Aims Semaphorin7A (Sema7A) plays an important role in the immunoregulation of the brain. In our study, we aimed to investigate the expression patterns of Sema7A in epilepsy and further explore the roles of Sema7A in the regulation of seizure activity and the inflammatory response in PTZ‐kindled epileptic rats. Methods First, we measured the Sema7A expression levels in patients with temporal lobe epilepsy (TLE) and in rats of a PTZ‐kindled epilepsy rat model. Second, to explore the role of Sema7A in the regulation of seizure activity, we conducted epilepsy‐related behavioral experiments after knockdown and overexpression of Sema7A in the rat hippocampal dentate gyrus (DG). Possible Sema7A‐related brain immune regulators (eg, ERK phosphorylation, IL‐6, and TNF‐α) were also investigated. Additionally, the growth of mossy fibers was visualized by anterograde tracing using injections of biotinylated dextran amine (BDA) into the DG region. Results Sema7A expression was markedly upregulated in the brain tissues of TLE patients and rats of the epileptic model after PTZ kindling. After knockdown of Sema7A, seizure activity was suppressed based on the latency to the first epileptic seizure, number of seizures, and duration of seizures. Conversely, overexpression of Sema7A promoted seizures. Overexpression of Sema7A increased the expression levels of the inflammatory cytokines, IL‐6 and TNF‐α, ERK phosphorylation, and growth of mossy fibers in PTZ‐kindled epileptic rats. Conclusion Sema7A is upregulated in the epileptic brain and plays a potential role in the regulation of seizure activity in PTZ‐kindled epileptic rats, which may be related to neuroinflammation. Sema7A promotes the inflammatory cytokines TNF‐α and IL‐6 as well as the growth of mossy fibers through the ERK pathway, suggesting that Sema7A may promote seizures by increasing neuroinflammation and activating pathological neural circuits. Sema7A plays a critical role in epilepsy and could be a potential therapeutic target for this neurological disorder.
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Affiliation(s)
- Jing Deng
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chonqing, China.,Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chonqing, China
| | - Tao Xu
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chonqing, China
| | - Juan Yang
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chonqing, China
| | - Ke-Ming Zhang
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chonqing, China
| | - Qi Li
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chonqing, China
| | - Xin-Yuan Yu
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chonqing, China
| | - Rong Li
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chonqing, China
| | - Jie Fu
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chonqing, China
| | - Qian Jiang
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chonqing, China
| | - Jing-Xi Ma
- Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chonqing, China.,Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, China
| | - Yang-Mei Chen
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chonqing, China
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Colín-Castelán D, Zaina S. Associations between atherosclerosis and neurological diseases, beyond ischemia-induced cerebral damage. Rev Endocr Metab Disord 2019; 20:15-25. [PMID: 30891682 DOI: 10.1007/s11154-019-09486-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Neurodegeneration is traditionally viewed as a consequence of peptide accumulation in the brain, stroke and/or cerebral ischemia. Nonetheless, a number of scattered observations suggest that neurological disease and atherosclerosis may be linked by more complex mechanisms. Understanding the intricate link between atherosclerosis and neurological conditions may have a significant impact on the quality of life of the growing ageing population and of high cardiovascular risk groups in general. Epidemiological data support the notion that neurological dysfunction and atherosclerosis coexist long before any evident clinical complications of cardiovascular disease appear and may be causally linked. Baffling, often overlooked, molecular data suggest that nervous tissue-specific gene expression is relaxed specifically in the atheromatous vascular wall, and/or that a systemic dysregulation of genes involved in nervous system biology dictates a concomitant progression of neurological disease and atherosclerosis. Further epidemiological and experimental work is needed to clarify the details and clinical relevance of those complex links.
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Affiliation(s)
- Dannia Colín-Castelán
- Department of Medical Sciences, Division of Health Sciences, Campus León, University of Guanajuato, León, Guanajuato, Mexico.
| | - Silvio Zaina
- Department of Medical Sciences, Division of Health Sciences, Campus León, University of Guanajuato, León, Guanajuato, Mexico
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Calcium Channel Subunit α2δ4 Is Regulated by Early Growth Response 1 and Facilitates Epileptogenesis. J Neurosci 2019; 39:3175-3187. [PMID: 30792272 DOI: 10.1523/jneurosci.1731-18.2019] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 12/03/2018] [Accepted: 01/08/2019] [Indexed: 12/17/2022] Open
Abstract
Transient brain insults, including status epilepticus (SE), can trigger a period of epileptogenesis during which functional and structural reorganization of neuronal networks occurs resulting in the onset of focal epileptic seizures. In recent years, mechanisms that regulate the dynamic transcription of individual genes during epileptogenesis and thereby contribute to the development of a hyperexcitable neuronal network have been elucidated. Our own results have shown early growth response 1 (Egr1) to transiently increase expression of the T-type voltage-dependent Ca2+ channel (VDCC) subunit CaV3.2, a key proepileptogenic protein. However, epileptogenesis involves complex and dynamic transcriptomic alterations; and so far, our understanding of the transcriptional control mechanism of gene regulatory networks that act in the same processes is limited. Here, we have analyzed whether Egr1 acts as a key transcriptional regulator for genes contributing to the development of hyperexcitability during epileptogenesis. We found Egr1 to drive the expression of the VDCC subunit α2δ4, which was augmented early and persistently after pilocarpine-induced SE. Furthermore, we show that increasing levels of α2δ4 in the CA1 region of the hippocampus elevate seizure susceptibility of mice by slightly decreasing local network activity. Interestingly, we also detected increased expression levels of Egr1 and α2δ4 in human hippocampal biopsies obtained from epilepsy surgery. In conclusion, Egr1 controls the abundance of the VDCC subunits CaV3.2 and α2δ4, which act synergistically in epileptogenesis, and thereby contributes to a seizure-induced "transcriptional Ca2+ channelopathy."SIGNIFICANCE STATEMENT The onset of focal recurrent seizures often occurs after an epileptogenic process induced by transient insults to the brain. Recently, transcriptional control mechanisms for individual genes involved in converting neurons hyperexcitable have been identified, including early growth response 1 (Egr1), which activates transcription of the T-type Ca2+ channel subunit CaV3.2. Here, we find Egr1 to regulate also the expression of the voltage-dependent Ca2+ channel subunit α2δ4, which was augmented after pilocarpine- and kainic acid-induced status epilepticus. In addition, we observed that α2δ4 affected spontaneous network activity and the susceptibility for seizure induction. Furthermore, we detected corresponding dynamics in human biopsies from epilepsy patients. In conclusion, Egr1 orchestrates a seizure-induced "transcriptional Ca2+ channelopathy" consisting of CaV3.2 and α2δ4, which act synergistically in epileptogenesis.
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Epilepsy Associates with Decreased HIF-1α/STAT5b Signaling in Glioblastoma. Cancers (Basel) 2019; 11:cancers11010041. [PMID: 30621209 PMCID: PMC6356242 DOI: 10.3390/cancers11010041] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/21/2018] [Accepted: 12/28/2018] [Indexed: 02/06/2023] Open
Abstract
Epilepsy at presentation is an independent favorable prognostic factor in glioblastoma (GBM). In this study, we analyze the oncologic signaling pathways that associate with epilepsy in human GBMs, and that can underlie this prognostic effect. Following ethical approval and patient consent, fresh frozen GBM tissue was obtained from 76 patient surgeries. Hospital records were screened for the presence of seizures at presentation of the disease. mRNA and miRNA expression-based and gene set enrichment analyses were performed on these tissues, to uncover candidate oncologic pathways that associate with epilepsy. We performed qPCR experiments and immunohistochemistry on tissue microarrays containing 286 GBMs to further explore the association of these candidate pathways and of markers of mesenchymal transformation (NF-κB, CEBP-β, STAT3, STAT5b, VEGFA, SRF) with epilepsy. Gene sets involved in hypoxia/HIF-1α, STAT5, CEBP-β and epithelial-mesenchymal transformation signaling were significantly downregulated in epileptogenic GBMs. On confirmatory protein expression analyses, epileptogenic tumors were characterized by a significant downregulation of phospho-STAT5b, a target of HIF-1α. Epilepsy status did not associate with molecular subclassification or miRNA expression patterns of the tumors. Epileptogenic GBMs correlate with decreased hypoxia/ HIF-1α/STAT5b signaling compared to glioblastomas that do not present with epilepsy.
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Single-molecule imaging of the transcription factor SRF reveals prolonged chromatin-binding kinetics upon cell stimulation. Proc Natl Acad Sci U S A 2018; 116:880-889. [PMID: 30598445 PMCID: PMC6338867 DOI: 10.1073/pnas.1812734116] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
How transcription factors (TFs) activate transcription is a long-standing but still unsolved question. We analyzed serum response factor (SRF), a stimulus-responsive TF mediating immediate early gene (IEG) and cytoskeletal gene expression at single-molecule resolution. Cell stimulation enhanced SRF activity by increasing the number of long chromatin-associated SRF molecules in an oscillating pattern. Further, stimulation enhanced the SRF chromatin residence time, and SRF binding events segregated into three distinct residence time regimes (short, intermediate, and long bound). In summary, our single-molecule imaging study reveals highly dynamic and diverse SRF interactions with DNA. Thus, cell stimulation regulates TF activity by several interconnected mechanisms including nucleus−cytoplasm shuttling, TF phosphorylation, cofactor recruitment, and extension of chromatin residence time and enhancing chromatin-bound TF numbers. Serum response factor (SRF) mediates immediate early gene (IEG) and cytoskeletal gene expression programs in almost any cell type. So far, SRF transcriptional dynamics have not been investigated at single-molecule resolution. We provide a study of single Halo-tagged SRF molecules in fibroblasts and primary neurons. In both cell types, individual binding events of SRF molecules segregated into three chromatin residence time regimes, short, intermediate, and long binding, indicating a cell type-independent SRF property. The chromatin residence time of the long bound fraction was up to 1 min in quiescent cells and significantly increased upon stimulation. Stimulation also enhanced the long bound SRF fraction at specific timepoints (20 and 60 min) in both cell types. These peaks correlated with activation of the SRF cofactors MRTF-A and MRTF-B (myocardin-related transcription factors). Interference with signaling pathways and cofactors demonstrated modulation of SRF chromatin occupancy by actin signaling, MAP kinases, and MRTFs.
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Chandrasekar A, Aksan B, Heuvel FO, Förstner P, Sinske D, Rehman R, Palmer A, Ludolph A, Huber-Lang M, Böckers T, Mauceri D, Knöll B, Roselli F. Neuroprotective effect of acute ethanol intoxication in TBI is associated to the hierarchical modulation of early transcriptional responses. Exp Neurol 2018; 302:34-45. [PMID: 29306704 DOI: 10.1016/j.expneurol.2017.12.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 12/08/2017] [Accepted: 12/30/2017] [Indexed: 01/01/2023]
Abstract
Ethanol intoxication is a risk factor for traumatic brain injury (TBI) but clinical evidence suggests that it may actually improve the prognosis of intoxicated TBI patients. We have employed a closed, weight-drop TBI model of different severity (2cm or 3cm falling height), preceded (-30min) or followed (+20min) by ethanol administration (5g/Kg). This protocol allows us to study the interaction of binge ethanol intoxication in TBI, monitoring behavioral changes, histological responses and the transcriptional regulation of a series of activity-regulated genes (immediate early genes, IEGs). We demonstrate that ethanol pretreatment before moderate TBI (2cm) significantly reduces neurological impairment and accelerates recovery. In addition, better preservation of neuronal numbers and cFos+cells was observed 7days after TBI. At transcriptional level, ethanol reduced the upregulation of a subset of IEGs encoding for transcription factors such as Atf3, c-Fos, FosB, Egr1, Egr3 and Npas4 but did not affect the upregulation of others (e.g. Gadd45b and Gadd45c). While a subset of IEGs encoding for effector proteins (such as Bdnf, InhbA and Dusp5) were downregulated by ethanol, others (such as Il-6) were unaffected. Notably, the majority of genes were sensitive to ethanol only when administered before TBI and not afterwards (the exceptions being c-Fos, Egr1 and Dusp5). Furthermore, while severe TBI (3cm) induced a qualitatively similar (but quantitatively larger) transcriptional response to moderate TBI, it was no longer sensitive to ethanol pretreatment. Thus, we have shown that a subset of the TBI-induced transcriptional responses were sensitive to ethanol intoxication at the instance of trauma (ultimately resulting in beneficial outcomes) and that the effect of ethanol was restricted to a certain time window (pre TBI treatment) and to TBI severity (moderate). This information could be critical for the translational value of ethanol in TBI and for the design of clinical studies aimed at disentangling the role of ethanol intoxication in TBI.
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Affiliation(s)
| | - Bahar Aksan
- Dept. of Neurobiology, IZN, University of Heidelberg, Germany
| | | | - Philip Förstner
- Institute of Physiological Chemistry, Ulm University, Germany
| | - Daniela Sinske
- Institute of Physiological Chemistry, Ulm University, Germany
| | | | - Annette Palmer
- Institute of Clinical and Experimental Trauma-Immunology, Ulm University, Germany
| | | | - Markus Huber-Lang
- Institute of Clinical and Experimental Trauma-Immunology, Ulm University, Germany
| | - Tobias Böckers
- Dept. of Anatomy and Cell Biology, Ulm University, Germany
| | - Daniela Mauceri
- Dept. of Neurobiology, IZN, University of Heidelberg, Germany
| | - Bernd Knöll
- Institute of Physiological Chemistry, Ulm University, Germany
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Jaworski J, Kalita K, Knapska E. c-Fos and neuronal plasticity: the aftermath of Kaczmarek’s theory. Acta Neurobiol Exp (Wars) 2018. [DOI: 10.21307/ane-2018-027] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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