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Lederbogen RC, Hoffjan S, Thiels C, Mau-Holzmann UA, Singer S, Yusenko MV, Nguyen HHP, Gerding WM. Optical Genome Mapping Reveals Disruption of the RASGRF2 Gene in a Patient with Developmental Delay Carrying a De Novo Balanced Reciprocal Translocation. Genes (Basel) 2024; 15:809. [PMID: 38927744 DOI: 10.3390/genes15060809] [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: 04/30/2024] [Revised: 06/10/2024] [Accepted: 06/15/2024] [Indexed: 06/28/2024] Open
Abstract
While balanced reciprocal translocations are relatively common, they often remain clinically silent unless they lead to the disruption of functional genes. In this study, we present the case of a boy exhibiting developmental delay and mild intellectual disability. Initial karyotyping revealed a translocation t(5;6)(q13;q23) between chromosomes 5 and 6 with limited resolution. Optical genome mapping (OGM) enabled a more precise depiction of the breakpoint regions involved in the reciprocal translocation. While the breakpoint region on chromosome 6 did not encompass any known gene, OGM revealed the disruption of the RASGRF2 (Ras protein-specific guanine nucleotide releasing factor 2) gene on chromosome 5, implicating RASGRF2 as a potential candidate gene contributing to the observed developmental delay in the patient. Variations in RASGRF2 have so far not been reported in developmental delay, but research on the RASGRF2 gene underscores its significance in various aspects of neurodevelopment, including synaptic plasticity, signaling pathways, and behavioral responses. This study highlights the utility of OGM in identifying breakpoint regions, providing possible insights into the understanding of neurodevelopmental disorders. It also helps affected individuals in gaining more knowledge about potential causes of their conditions.
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Affiliation(s)
| | - Sabine Hoffjan
- Department of Human Genetics, Ruhr-University Bochum, 44801 Bochum, Germany
| | - Charlotte Thiels
- Department of Neuropediatrics, University Children's Hospital, Ruhr-University Bochum, 44791 Bochum, Germany
| | | | - Sylke Singer
- Institute of Medical Genetics and Applied Genomics, University Tübingen, 72074 Tübingen, Germany
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Ge Y, Wang YT. GluN2B-containing NMDARs in the mammalian brain: pharmacology, physiology, and pathology. Front Mol Neurosci 2023; 16:1190324. [PMID: 37324591 PMCID: PMC10264587 DOI: 10.3389/fnmol.2023.1190324] [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: 03/20/2023] [Accepted: 04/24/2023] [Indexed: 06/17/2023] Open
Abstract
Glutamate N-methyl-D-aspartate receptor (NMDAR) is critical for promoting physiological synaptic plasticity and neuronal viability. As a major subpopulation of the NMDAR, the GluN2B subunit-containing NMDARs have distinct pharmacological properties, physiological functions, and pathological relevance to neurological diseases compared with other NMDAR subtypes. In mature neurons, GluN2B-containing NMDARs are likely expressed as both diheteromeric and triheteromeric receptors, though the functional importance of each subpopulation has yet to be disentangled. Moreover, the C-terminal region of the GluN2B subunit forms structural complexes with multiple intracellular signaling proteins. These protein complexes play critical roles in both activity-dependent synaptic plasticity and neuronal survival and death signaling, thus serving as the molecular substrates underlying multiple physiological functions. Accordingly, dysregulation of GluN2B-containing NMDARs and/or their downstream signaling pathways has been implicated in neurological diseases, and various strategies to reverse these deficits have been investigated. In this article, we provide an overview of GluN2B-containing NMDAR pharmacology and its key physiological functions, highlighting the importance of this receptor subtype during both health and disease states.
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Affiliation(s)
- Yang Ge
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Yu Tian Wang
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
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3
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Liao P, Wu QY, Li S, Hu KB, Liu HL, Wang HY, Long ZY, Lu XM, Wang YT. The ameliorative effects and mechanisms of abscisic acid on learning and memory. Neuropharmacology 2023; 224:109365. [PMID: 36462635 DOI: 10.1016/j.neuropharm.2022.109365] [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: 09/02/2022] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 12/03/2022]
Abstract
Abscisic acid (ABA), a conserved hormone existing in plants and animals, not only regulates blood glucose and inflammation but also has good therapeutic effects on obesity, diabetes, atherosclerosis and inflammatory diseases in animals. Studies have shown that exogenous ABA can pass the blood-brain barrier and inhibit neuroinflammation, promote neurogenesis, enhance synaptic plasticity, improve learning, memory and cognitive ability in the central nervous system. At the same time, ABA plays a crucial role in significant improvement of Alzheimer's disease, depression, and anxiety. Here we review the previous research progress of ABA on the physiological effects and clinical application in the related diseases. By summarizing the biological functions of ABA, we aim to reveal the possible mechanisms of ameliorative function of ABA on learning and memory, to provide a theoretical basis that ABA as a novel and safe drug improves learning memory and cognitive impairment in central system diseases such as aging, neurodegenerative diseases and traumatic brain injury.
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Affiliation(s)
- Ping Liao
- College of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, 400054, China; State Key Laboratory of Trauma, Burns and Combined Injury, Daping Hospital, Army Medical University, Chongqing, 400042, China
| | - Qing-Yun Wu
- College of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Sen Li
- State Key Laboratory of Trauma, Burns and Combined Injury, Daping Hospital, Army Medical University, Chongqing, 400042, China
| | - Kai-Bin Hu
- College of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Hui-Lin Liu
- College of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Hai-Yan Wang
- State Key Laboratory of Trauma, Burns and Combined Injury, Daping Hospital, Army Medical University, Chongqing, 400042, China
| | - Zai-Yun Long
- State Key Laboratory of Trauma, Burns and Combined Injury, Daping Hospital, Army Medical University, Chongqing, 400042, China
| | - Xiu-Min Lu
- College of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, 400054, China.
| | - Yong-Tang Wang
- State Key Laboratory of Trauma, Burns and Combined Injury, Daping Hospital, Army Medical University, Chongqing, 400042, China.
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Morella I, Pohořalá V, Calpe-López C, Brambilla R, Spanagel R, Bernardi RE. Nicotine self-administration and ERK signaling are altered in RasGRF2 knockout mice. Front Pharmacol 2022; 13:986566. [PMID: 36120353 PMCID: PMC9479000 DOI: 10.3389/fphar.2022.986566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 08/10/2022] [Indexed: 11/29/2022] Open
Abstract
Ras/Raf/MEK/ERK (Ras-ERK) signaling has been demonstrated to play a role in the effects of drugs of abuse such as cocaine and alcohol, but has not been extensively examined in nicotine-related reward behaviors. We examined the role of Ras Guanine Nucleotide Releasing Factor 2 (RasGRF2), an upstream mediator of the Ras-ERK signaling pathway, on nicotine self-administration (SA) in RasGRF2 KO and WT mice. We first demonstrated that acute nicotine exposure (0.4 mg/kg) resulted in an increase in phosphorylated ERK1/2 (pERK1/2) in the striatum, consistent with previous reports. We also demonstrated that increases in pERK1/2 resulting from acute (0.4 mg/kg) and repeated (0.4 mg/kg, 10 daily injections) exposure to nicotine in WT mice were not present in RasGRF2 KO mice, confirming that RasGRF2 at least partly regulates the activity of the Ras-ERK signaling pathway following nicotine exposure. We then performed intravenous nicotine SA (0.03 mg/kg/infusion for 10 days) in RasGRF2 KO and WT mice. Consistent with a previous report using cocaine SA, RasGRF2 KO mice demonstrated an increase in nicotine SA relative to WT controls. These findings suggest a role for RasGRF2 in the reinforcing effects of nicotine, and implicate the Ras-ERK signaling pathway as a common mediator of the response to drugs of abuse.
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Affiliation(s)
- Ilaria Morella
- Neuroscience and Mental Health Innovation Institute, Cardiff University, Cardiff, United Kingdom.,Division of Neuroscience, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Veronika Pohořalá
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Claudia Calpe-López
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Riccardo Brambilla
- Neuroscience and Mental Health Innovation Institute, Cardiff University, Cardiff, United Kingdom.,Division of Neuroscience, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Rainer Spanagel
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Rick E Bernardi
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
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5
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Ye Y, Li H, Bian J, Wang L, Wang Y, Huang H. Exploring Prognosis-Associated Biomarkers of Estrogen-Independent Uterine Corpus Endometrial Carcinoma by Bioinformatics Analysis. Int J Gen Med 2021; 14:9067-9081. [PMID: 34876842 PMCID: PMC8643178 DOI: 10.2147/ijgm.s341345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Accepted: 11/16/2021] [Indexed: 11/23/2022] Open
Abstract
Background Uterine corpus endometrial carcinoma (UCEC) is one of the most common female cancers with high incidence and mortality rates. In particular, the prognosis of type II UCEC is poorer than that of type I. However, the molecular mechanism underlying type II UCEC remains unclear. Methods RNA-seq data and corresponding clinical information on UCEC patients were downloaded from The Cancer Genome Atlas database, which were then separated into mRNA, lncRNA, and miRNA gene expression profile matrix to perform differentially expressed gene analysis. Weighted gene co-expression network analysis (WGCNA) was used to identify key modules associated with different UCEC subtypes based on mRNA and lncRNA expression matrix. Following that, a subtype-associated competing endogenous RNA (ceRNA) regulatory network was constructed. In addition, GO functional annotation and KEGG pathway analysis were performed on subtype-related DE mRNAs, and STRING database was utilized to predict the interaction network between proteins and their biological functions. The key mRNAs were validated at the protein and gene expression levels in endometrial cancerous tissues as compared with normal tissues. Results In summary, we identified 4611 mRNA, 3568 lncRNAs, and 47 miRNAs as differentially expressed between endometrial cancerous tissues and normal endometrial tissues. WGCNA demonstrated that 72 mRNAs and 55 lncRNAs were correlated with pathological subtypes. In the constructed ceRNA regulatory network, LINC02418, RASGRF1, and GCNT1 were screened for their association with poor prognosis of type II UCEC. These DE mRNAs were linked to Wnt signaling pathway, and lower expression of LEF1 and NKD1 predicted advanced clinical stages and worse prognosis of UCEC patients. Conclusion This study revealed five prognosis-associated biomarkers that can be used to predict the worst prognosis of type II UCEC.
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Affiliation(s)
- Youchun Ye
- Department of Gynecology and Obstetrics, The Affiliated People's Hospital of Ningbo University, Ningbo, Zhejiang, 315040, People's Republic of China
| | - Hongfeng Li
- Department of Gynecology and Obstetrics, The Affiliated People's Hospital of Ningbo University, Ningbo, Zhejiang, 315040, People's Republic of China
| | - Jia Bian
- Department of Gynecology and Obstetrics, The Affiliated People's Hospital of Ningbo University, Ningbo, Zhejiang, 315040, People's Republic of China
| | - Liangfei Wang
- Department of Gynecology and Obstetrics, The Affiliated People's Hospital of Ningbo University, Ningbo, Zhejiang, 315040, People's Republic of China
| | - Yijie Wang
- Department of Gynecology and Obstetrics, The Affiliated People's Hospital of Ningbo University, Ningbo, Zhejiang, 315040, People's Republic of China
| | - Hui Huang
- Department of Gynecology and Obstetrics, The Affiliated People's Hospital of Ningbo University, Ningbo, Zhejiang, 315040, People's Republic of China
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van Duijvenboden S, Ramírez J, Young WJ, Orini M, Mifsud B, Tinker A, Lambiase PD, Munroe PB. Genomic and pleiotropic analyses of resting QT interval identifies novel loci and overlap with atrial electrical disorders. Hum Mol Genet 2021; 30:2513-2523. [PMID: 34274964 PMCID: PMC8643508 DOI: 10.1093/hmg/ddab197] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 05/26/2021] [Accepted: 06/17/2021] [Indexed: 11/13/2022] Open
Abstract
The resting QT interval, an electrocardiographic (ECG) measure of ventricular myocardial repolarization, is a heritable risk marker of cardiovascular mortality, but the mechanisms remain incompletely understood. Previously reported candidate genes have provided insights into the regulatory mechanisms of the QT interval. However, there are still important knowledge gaps. We aimed to gain new insights by (i) providing new candidate genes, (ii) identifying pleiotropic associations with other cardiovascular traits, and (iii) scanning for sexually dimorphic genetic effects. We conducted a genome-wide association analysis for resting QT interval with ~9.8 million variants in 52 107 individuals of European ancestry without known cardiovascular disease from the UK Biobank. We identified 40 loci, 13 of which were novel, including 2 potential sex-specific loci, explaining ~11% of the trait variance. Candidate genes at novel loci were involved in myocardial structure and arrhythmogenic cardiomyopathy. Investigation of pleiotropic effects of QT interval variants using phenome-wide association analyses in 302 000 unrelated individuals from the UK Biobank and pairwise genome-wide comparisons with other ECG and cardiac imaging traits revealed genetic overlap with atrial electrical pathology. These findings provide novel insights into how abnormal myocardial repolarization and increased cardiovascular mortality may be linked.
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Affiliation(s)
- Stefan van Duijvenboden
- Institute of Cardiovascular Science, University College London, London WC1E 6BT, UK
- Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK
| | - Julia Ramírez
- Institute of Cardiovascular Science, University College London, London WC1E 6BT, UK
- Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK
| | - William J Young
- Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK
- Barts Heart Centre, St Bartholomew’s Hospital, London EC1A 7BE, UK
| | - Michele Orini
- Institute of Cardiovascular Science, University College London, London WC1E 6BT, UK
| | - Borbala Mifsud
- Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha PO 34110, Qatar
| | - Andrew Tinker
- Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK
- NIHR Barts Cardiovascular Biomedical Research Unit, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK
| | - Pier D Lambiase
- Institute of Cardiovascular Science, University College London, London WC1E 6BT, UK
- Barts Heart Centre, St Bartholomew’s Hospital, London EC1A 7BE, UK
| | - Patricia B Munroe
- Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK
- NIHR Barts Cardiovascular Biomedical Research Unit, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK
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Miningou Zobon NT, Jędrzejewska-Szmek J, Blackwell KT. Temporal pattern and synergy influence activity of ERK signaling pathways during L-LTP induction. eLife 2021; 10:e64644. [PMID: 34374340 PMCID: PMC8363267 DOI: 10.7554/elife.64644] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 08/03/2021] [Indexed: 01/21/2023] Open
Abstract
Long-lasting long-term potentiation (L-LTP) is a cellular mechanism of learning and memory storage. Studies have demonstrated a requirement for extracellular signal-regulated kinase (ERK) activation in L-LTP produced by a diversity of temporal stimulation patterns. Multiple signaling pathways converge to activate ERK, with different pathways being required for different stimulation patterns. To answer whether and how different temporal patterns select different signaling pathways for ERK activation, we developed a computational model of five signaling pathways (including two novel pathways) leading to ERK activation during L-LTP induction. We show that calcium and cAMP work synergistically to activate ERK and that stimuli given with large intertrial intervals activate more ERK than shorter intervals. Furthermore, these pathways contribute to different dynamics of ERK activation. These results suggest that signaling pathways with different temporal sensitivities facilitate ERK activation to diversity of temporal patterns.
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Affiliation(s)
| | - Joanna Jędrzejewska-Szmek
- Laboratory of Neuroinformatic, Nencki Institute of Experimental Biology of Polish Academy of SciencesWarsawPoland
| | - Kim T Blackwell
- Interdisciplinary Program in Neuroscience, Bioengineering Department, George Mason UniversityFairfaxUnited States
- Krasnow Institute for Advanced Study, George Mason UniversityFairfaxUnited States
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8
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Fernández-Medarde A, Santos E. Ras GEF Mouse Models for the Analysis of Ras Biology and Signaling. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2021; 2262:361-395. [PMID: 33977490 DOI: 10.1007/978-1-0716-1190-6_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Animal models have become in recent years a crucial tool to understand the physiological and pathological roles of many cellular proteins. They allow analysis of the functional consequences of [1] complete or partial (time- or organ-limited) removal of specific proteins (knockout animals), [2] the exchange of a wild-type allele for a mutant or truncated version found in human illnesses (knock-in), or [3] the effect of overexpression of a given protein in the whole body or in specific organs (transgenic mice). In this regard, the study of phenotypes in Ras GEF animal models has allowed researchers to find specific functions for otherwise very similar proteins, uncovering their role in physiological contexts such as memory formation, lymphopoiesis, photoreception, or body homeostasis. In addition, mouse models have been used to unveil the functional role of Ras GEFs under pathological conditions, including Noonan syndrome, skin tumorigenesis, inflammatory diseases, diabetes, or ischemia among others. In the following sections, we will describe the methodological approaches employed for Ras GEF animal model analyses, as well as the main discoveries made.
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Affiliation(s)
- Alberto Fernández-Medarde
- Centro de Investigación del Cáncer-Instituto de Biología Molecular y Celular del Cáncer (CSIC-Universidad de Salamanca) and CIBERONC, Salamanca, Spain.
| | - Eugenio Santos
- Centro de Investigación del Cáncer-Instituto de Biología Molecular y Celular del Cáncer (CSIC-Universidad de Salamanca) and CIBERONC, Salamanca, Spain
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9
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Olevska A, Spanagel R, Bernardi RE. Impaired contextual fear conditioning in RasGRF2 mutant mice is likely Ras-ERK-dependent. Neurobiol Learn Mem 2021; 181:107435. [PMID: 33831510 DOI: 10.1016/j.nlm.2021.107435] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 03/08/2021] [Accepted: 03/31/2021] [Indexed: 10/21/2022]
Abstract
Ras/Raf/MEK/ERK (Ras-ERK) signaling has been shown to play an important role in fear acquisition. However, little information is known regarding the mechanisms that contribute to the regulation of this pathway in terms of the learning of conditioned fears. Ras Guanine Nucleotide Releasing Factor 2 (RasGRF2) is one of two guanine nucleotide exchange factors (GEF) that regulates the Ras-ERK signaling pathway in a Ca2+-dependent manner via control of the cycling of Ras isoforms between an inactive and active state. Here we sought to determine the role of RasGRF2 on contextual fear conditioning in RasGRF2 knockout (KO) and their wild type (WT) counterparts. Male KO and WT mice underwent a single session of contextual fear conditioning (12 min, 4 unsignaled shocks), followed by either daily 12-min retention trials or the molecular analysis of Ras activation and pERK1/2 activity. KO mice showed an impaired acquisition of contextual fear, as demonstrated by reduced freezing during fear conditioning and 24-hr retention tests relative to WT mice. Ras analysis following fear conditioning demonstrated a reduction in Ras activation in the hippocampus as well as a reduction in pERK1/2 in the CA1 region of the hippocampus in KO mice, suggesting that the decrease in fear conditioning in KO mice is at least in part due to the impairment of Ras-ERK signaling in the hippocampus during learning. These data indicate a role for RasGRF2 in contextual fear conditioning in mice that may be Ras-ERK-dependent.
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Affiliation(s)
- Anastasia Olevska
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | - Rainer Spanagel
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | - Rick E Bernardi
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany.
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10
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Lavin KM, Ge Y, Sealfon SC, Nair VD, Wilk K, McAdam JS, Windham ST, Kumar PL, McDonald MLN, Bamman MM. Rehabilitative Impact of Exercise Training on Human Skeletal Muscle Transcriptional Programs in Parkinson's Disease. Front Physiol 2020; 11:653. [PMID: 32625117 PMCID: PMC7311784 DOI: 10.3389/fphys.2020.00653] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 05/22/2020] [Indexed: 12/18/2022] Open
Abstract
Parkinson's disease (PD) is the most common motor neurodegenerative disease, and neuromuscular function deficits associated with PD contribute to disability. Targeting these symptoms, our laboratory has previously evaluated 16-week high-intensity resistance exercise as rehabilitative training (RT) in individuals with PD. We reported significant improvements in muscle mass, neuromuscular function (strength, power, and motor unit activation), indices of neuromuscular junction integrity, total and motor scores on the unified Parkinson's disease rating scale (UPDRS), and total and sub-scores on the 39-item PD Quality of Life Questionnaire (PDQ-39), supporting the use of RT to reverse symptoms. Our objective was to identify transcriptional networks that may contribute to RT-induced neuromuscular remodeling in PD. We generated transcriptome-wide skeletal muscle RNA-sequencing in 5 participants with PD [4M/1F, 67 ± 2 years, Hoehn and Yahr stages 2 (n = 3) and 3 (n = 2)] before and after 16-week high intensity RT to identify transcriptional networks that may in part underpin RT-induced neuromuscular remodeling in PD. Following RT, 304 genes were significantly upregulated, notably related to remodeling and nervous system/muscle development. Additionally, 402 genes, primarily negative regulators of muscle adaptation, were downregulated. We applied the recently developed Pathway-Level Information ExtractoR (PLIER) method to reveal coordinated gene programs (as latent variables, LVs) that differed in skeletal muscle among young (YA) and old (OA) healthy adults and PD (n = 12 per cohort) at baseline and in PD pre- vs. post-RT. Notably, one LV associated with angiogenesis, axon guidance, and muscle remodeling was significantly lower in PD than YA at baseline and was significantly increased by exercise. A different LV annotated to denervation, autophagy, and apoptosis was increased in both PD and OA relative to YA and was also reduced by 16-week RT in PD. Thus, this analysis identified two novel skeletal muscle transcriptional programs that are dysregulated by PD and aging, respectively. Notably, RT has a normalizing effect on both programs in individuals with PD. These results identify potential molecular transducers of the RT-induced improvements in neuromuscular remodeling and motor function that may aid in optimizing exercise rehabilitation strategies for individuals with PD.
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Affiliation(s)
- Kaleen M. Lavin
- Department of Cell, Developmental and Integrative Biology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- UAB Center for Exercise Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Yongchao Ge
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Center for Advanced Research on Diagnostic Assays, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Stuart C. Sealfon
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Center for Advanced Research on Diagnostic Assays, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Venugopalan D. Nair
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Center for Advanced Research on Diagnostic Assays, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Katarzyna Wilk
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Center for Advanced Research on Diagnostic Assays, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Jeremy S. McAdam
- Department of Cell, Developmental and Integrative Biology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- UAB Center for Exercise Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Samuel T. Windham
- UAB Center for Exercise Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Surgery, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Preeti Lakshman Kumar
- Department of Genetics, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Merry-Lynn N. McDonald
- Department of Genetics, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Marcas M. Bamman
- Department of Cell, Developmental and Integrative Biology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- UAB Center for Exercise Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Birmingham/Atlanta VA Geriatric Research, Education, and Clinical Center, Birmingham, AL, United States
- Department of Neurology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
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11
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Jin SX, Dickson D, Maguire J, Feig LA. RASGRF1 in CRF cells controls the early adolescent female response to repeated stress. J Endocrinol 2020; 245:397-410. [PMID: 32240981 PMCID: PMC7297040 DOI: 10.1530/joe-19-0375] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 04/02/2020] [Indexed: 11/08/2022]
Abstract
RASGRF1 (GRF1) is a calcium-stimulated guanine-nucleotide exchange factor that activates RAS and RAC GTPases. In hippocampus neurons, it mediates the action of NMDA and calcium-permeable AMPA glutamate receptors on specific forms of synaptic plasticity, learning, and memory in both male and female mice. Recently, we showed GRF1 also regulates the HPA axis response to restraint stress, but only in female mice before puberty. In particular, we found that after 7 days of restraint stress (7DRS) (30 min/day) both elevated serum CORT levels and induction of an anxiolytic phenotype normally observed in early adolescent (EA) female mice are blocked in GRF1-knockout mice. In contrast, no effects were observed in EA male or adult females. Here, we show this phenotype is due, at least in part, to GRF1 loss in CRF cells of the paraventricular nucleus of the hypothalamus, as GRF1 knockout specifically in these cells suppressed 7DRS-induced elevation of serum CORT levels specifically in EA females, but only down to levels found in comparably stressed EA males. Nevertheless, it still completely blocked the 7DRS-induced anxiolytic phenotype observed in EA females. Interestingly, loss of GRF1 in CRF cells had no effect after only three restraint stress exposures, implying a role for GRF1 in 7DRS stress-induced plasticity of CRF cells that appears to be specific to EA female mice. Overall, these findings indicate that GRF1 in CRF cells makes a key contribution to the distinct response EA females display to repeated stress.
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Affiliation(s)
- Shan-xue Jin
- Department of Developmental, Molecular, and Chemical Biology
| | - David Dickson
- Department of Developmental, Molecular, and Chemical Biology
| | - Jamie Maguire
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111
| | - Larry A. Feig
- Department of Developmental, Molecular, and Chemical Biology
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111
- communicating author P- 617-636-6956,
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12
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Pleiotropic Roles of Calmodulin in the Regulation of KRas and Rac1 GTPases: Functional Diversity in Health and Disease. Int J Mol Sci 2020; 21:ijms21103680. [PMID: 32456244 PMCID: PMC7279331 DOI: 10.3390/ijms21103680] [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: 04/17/2020] [Revised: 05/18/2020] [Accepted: 05/21/2020] [Indexed: 12/21/2022] Open
Abstract
Calmodulin is a ubiquitous signalling protein that controls many biological processes due to its capacity to interact and/or regulate a large number of cellular proteins and pathways, mostly in a Ca2+-dependent manner. This complex interactome of calmodulin can have pleiotropic molecular consequences, which over the years has made it often difficult to clearly define the contribution of calmodulin in the signal output of specific pathways and overall biological response. Most relevant for this review, the ability of calmodulin to influence the spatiotemporal signalling of several small GTPases, in particular KRas and Rac1, can modulate fundamental biological outcomes such as proliferation and migration. First, direct interaction of calmodulin with these GTPases can alter their subcellular localization and activation state, induce post-translational modifications as well as their ability to interact with effectors. Second, through interaction with a set of calmodulin binding proteins (CaMBPs), calmodulin can control the capacity of several guanine nucleotide exchange factors (GEFs) to promote the switch of inactive KRas and Rac1 to an active conformation. Moreover, Rac1 is also an effector of KRas and both proteins are interconnected as highlighted by the requirement for Rac1 activation in KRas-driven tumourigenesis. In this review, we attempt to summarize the multiple layers how calmodulin can regulate KRas and Rac1 GTPases in a variety of cellular events, with biological consequences and potential for therapeutic opportunities in disease settings, such as cancer.
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13
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Abarzúa S, Ampuero E, Zundert B. Superoxide generation via the NR2B‐NMDAR/RasGRF1/NOX2 pathway promotes dendritogenesis. J Cell Physiol 2019; 234:22985-22995. [DOI: 10.1002/jcp.28859] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 05/03/2019] [Accepted: 05/03/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Sebastian Abarzúa
- Instituto de Ciencias Biomédicas, Facultad de Medicina y Facultad de la Ciencias de la Vida Universidad Andres Bello Santiago Chile
- Centro de Envejecimiento y Regeneración CARE Chile UC Santiago Chile
| | - Estibaliz Ampuero
- Instituto de Ciencias Biomédicas, Facultad de Medicina y Facultad de la Ciencias de la Vida Universidad Andres Bello Santiago Chile
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud Universidad Autónoma de Chile Santiago Chile
| | - Brigitte Zundert
- Instituto de Ciencias Biomédicas, Facultad de Medicina y Facultad de la Ciencias de la Vida Universidad Andres Bello Santiago Chile
- Centro de Envejecimiento y Regeneración CARE Chile UC Santiago Chile
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Umeda K, Negishi M, Katoh H. RasGRF1 mediates brain-derived neurotrophic factor-induced axonal growth in primary cultured cortical neurons. Biochem Biophys Rep 2018; 17:56-64. [PMID: 30582008 PMCID: PMC6295856 DOI: 10.1016/j.bbrep.2018.11.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 11/29/2018] [Indexed: 12/01/2022] Open
Abstract
The appropriate development and regulation of neuronal morphology are important to establish functional neuronal circuits and enable higher brain function of the central nervous system. R-Ras, a member of the Ras family of small GTPases, plays crucial roles in the regulation of axonal morphology, including outgrowth, branching, and guidance. GTP-bound activated R-Ras reorganizes actin filaments and microtubules through interactions with its downstream effectors, leading to the precise control of axonal morphology. However, little is known about the upstream regulatory mechanisms for R-Ras activation in neurons. In this study, we found that brain-derived neurotrophic factor (BDNF) has a positive effect on endogenous R-Ras activation and promotes R-Ras-mediated axonal growth. RNA interference knockdown and overexpression experiments revealed that RasGRF1, a guanine nucleotide exchange factor (GEF) for R-Ras, is involved in BDNF-induced R-Ras activation and the promotion of axonal growth. Phosphorylation of RasGRF1 by protein kinase A at Ser916/898 is needed for the full activation of its GEF activity and to facilitate Ras signaling. We observed that BDNF treatment markedly increased this phosphorylation. Our results suggest that BDNF is one of the critical extrinsic regulators for R-Ras activation, and that RasGRF1 is an intrinsic key mediator for BDNF-induced R-Ras activation and R-Ras-mediated axonal morphological regulation.
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Affiliation(s)
- Kentaro Umeda
- Laboratory of Molecular Neurobiology, Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Manabu Negishi
- Laboratory of Molecular Neurobiology, Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.,Laboratory of Molecular Neurobiology, Graduate School of Biostudies, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hironori Katoh
- Laboratory of Molecular Neurobiology, Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.,Laboratory of Molecular Neurobiology, Graduate School of Biostudies, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
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15
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Manyes L, Holst S, Lozano M, Santos E, Fernandez-Medarde A. Spatial learning and long-term memory impairments in RasGrf1 KO, Pttg1 KO, and double KO mice. Brain Behav 2018; 8:e01089. [PMID: 30259712 PMCID: PMC6236249 DOI: 10.1002/brb3.1089] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 06/12/2018] [Accepted: 07/01/2018] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND RasGrf1 is a guanine-nucleotide releasing factor that enhances Ras activity. Human PTTG1 is an oncoprotein found in pituitary tumors and later identified as securin, a protein isolated from yeast with a reported role in chromosome separation. It has been suggested that RasGrf1 is an important upstream component of signal transduction pathways regulating Pttg1 expression and controlling beta cell development and their physiological response. At memory formation level, there are contradictory data regarding the role of RasGrf1, while Pttg1 has not been previously studied. Both proteins are expressed in the mammalian hippocampus, which is one of the key brain areas for spatial learning and memory. OBJECTIVE The aim of this work was to study a potential link between RasGrf1 and Pttg1 in memory formation. METHOD Spatial learning and memory test in the Pttg1 KO, RasGrf1 KO, and Pttg1-RasGrf1 double KO and their correspondent WT mice using a Barnes maze. RESULTS In comparison with the WT control mice, Pttg1 KO mice learned how to solve the task in a less efficient way, suggesting problems in memory consolidation. RasGrf1 KO mice performance was similar to controls, and they learned to use the best searching strategy. Double KO mice reached a better spatial learning level than WT. CONCLUSION A role for Pttg1 in memory consolidation/formation is suggested, while our RasGrf1 KO mice do not show hippocampus associated memory defects.
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Affiliation(s)
- Lara Manyes
- Lab 1, Cancer Research Center, CSIC-Universidad de Salamanca & CIBERONC, Salamanca, Spain.,Laboratory of Food Sciences and Toxicology, Faculty of Pharmacy, Universitat de València, València, Spain
| | - Sarah Holst
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Manuel Lozano
- Laboratory of Food Sciences and Toxicology, Faculty of Pharmacy, Universitat de València, València, Spain
| | - Eugenio Santos
- Lab 1, Cancer Research Center, CSIC-Universidad de Salamanca & CIBERONC, Salamanca, Spain
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Abstract
The MAPK pathway is a prominent intracellular signaling pathway regulating various intracellular functions. Components of this pathway are mutated in a related collection of congenital syndromes collectively referred to as neuro-cardio-facio-cutaneous syndromes (NCFC) or Rasopathies. Recently, it has been appreciated that these disorders are associated with autism spectrum disorders (ASD). In addition, idiopathic ASD has also implicated the MAPK signaling cascade as a common pathway that is affected by many of the genetic variants that have been found to be linked to ASDs. This chapter describes the components of the MAPK pathway and how it is regulated. Furthermore, this chapter will highlight the various functions of the MAPK pathway during both embryonic development of the central nervous system (CNS) and its roles in neuronal physiology and ultimately, behavior. Finally, we will summarize the perturbations to MAPK signaling in various models of autism spectrum disorders and Rasopathies to highlight how dysregulation of this pivotal pathway may contribute to the pathogenesis of autism.
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17
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β-Subunit of the voltage-gated Ca 2+ channel Cav1.2 drives signaling to the nucleus via H-Ras. Proc Natl Acad Sci U S A 2018; 115:E8624-E8633. [PMID: 30150369 DOI: 10.1073/pnas.1805380115] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Depolarization-induced signaling to the nucleus by the L-type voltage-gated calcium channel Cav1.2 is widely assumed to proceed by elevating intracellular calcium. The apparent lack of quantitative correlation between Ca2+ influx and gene activation suggests an alternative activation pathway. Here, we demonstrate that membrane depolarization of HEK293 cells transfected with α11.2/β2b/α2δ subunits (Cav1.2) triggers c-Fos and MeCP2 activation via the Ras/ERK/CREB pathway. Nuclear signaling is lost either by absence of the intracellular β2 subunit or by transfecting the cells with the channel mutant α11.2W440A/β2b/α2δ, a mutation that disrupts the interaction between α11.2 and β2 subunits. Pulldown assays in neuronal SH-SY5Y cells and in vitro binding of recombinant H-Ras and β2 confirmed the importance of the intracellular β2 subunit for depolarization-induced gene activation. Using a Ca2+-impermeable mutant channel α11.2L745P/β2b/α2δ or disrupting Ca2+/calmodulin binding to the channel using the channel mutant α11.2I1624A/β2b/α2δ, we demonstrate that depolarization-induced c-Fos and MeCP2 activation does not depend on Ca2+ transport by the channel. Thus, in contrast to the paradigm that elevated intracellular Ca2+ drives nuclear signaling, we show that Cav1.2-triggered c-Fos or MeCP2 is dependent on extracellular Ca2+ and Ca2+ occupancy of the open channel pore, but is Ca2+-influx independent. An indispensable β-subunit interaction with H-Ras, which is triggered by conformational changes at α11.2 independently of Ca2+ flux, brings to light a master regulatory role of β2 in transcriptional activation via the ERK/CREB pathway. This mode of H-Ras activation could have broad implications for understanding the coupling of membrane depolarization to the rapid induction of gene transcription.
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18
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Igolkina AA, Armoskus C, Newman JRB, Evgrafov OV, McIntyre LM, Nuzhdin SV, Samsonova MG. Analysis of Gene Expression Variance in Schizophrenia Using Structural Equation Modeling. Front Mol Neurosci 2018; 11:192. [PMID: 29942251 PMCID: PMC6004421 DOI: 10.3389/fnmol.2018.00192] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 05/15/2018] [Indexed: 01/02/2023] Open
Abstract
Schizophrenia (SCZ) is a psychiatric disorder of unknown etiology. There is evidence suggesting that aberrations in neurodevelopment are a significant attribute of schizophrenia pathogenesis and progression. To identify biologically relevant molecular abnormalities affecting neurodevelopment in SCZ we used cultured neural progenitor cells derived from olfactory neuroepithelium (CNON cells). Here, we tested the hypothesis that variance in gene expression differs between individuals from SCZ and control groups. In CNON cells, variance in gene expression was significantly higher in SCZ samples in comparison with control samples. Variance in gene expression was enriched in five molecular pathways: serine biosynthesis, PI3K-Akt, MAPK, neurotrophin and focal adhesion. More than 14% of variance in disease status was explained within the logistic regression model (C-value = 0.70) by predictors accounting for gene expression in 69 genes from these five pathways. Structural equation modeling (SEM) was applied to explore how the structure of these five pathways was altered between SCZ patients and controls. Four out of five pathways showed differences in the estimated relationships among genes: between KRAS and NF1, and KRAS and SOS1 in the MAPK pathway; between PSPH and SHMT2 in serine biosynthesis; between AKT3 and TSC2 in the PI3K-Akt signaling pathway; and between CRK and RAPGEF1 in the focal adhesion pathway. Our analysis provides evidence that variance in gene expression is an important characteristic of SCZ, and SEM is a promising method for uncovering altered relationships between specific genes thus suggesting affected gene regulation associated with the disease. We identified altered gene-gene interactions in pathways enriched for genes with increased variance in expression in SCZ. These pathways and loci were previously implicated in SCZ, providing further support for the hypothesis that gene expression variance plays important role in the etiology of SCZ.
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Affiliation(s)
- Anna A Igolkina
- Institute of Applied Mathematics and Mechanics, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
| | - Chris Armoskus
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Jeremy R B Newman
- Department of Molecular Genetics & Microbiology, Genetics Institute, University of Florida, Gainesville, FL, United States
| | - Oleg V Evgrafov
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, NY, United States
| | - Lauren M McIntyre
- Department of Molecular Genetics & Microbiology, Genetics Institute, University of Florida, Gainesville, FL, United States
| | - Sergey V Nuzhdin
- Institute of Applied Mathematics and Mechanics, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia.,Molecular and Computation Biology, University of Southern California, Los Angeles, CA, United States
| | - Maria G Samsonova
- Institute of Applied Mathematics and Mechanics, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
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19
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Eisinger BE, Zhao X. Identifying molecular mediators of environmentally enhanced neurogenesis. Cell Tissue Res 2018; 371:7-21. [PMID: 29127518 PMCID: PMC5826587 DOI: 10.1007/s00441-017-2718-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 10/16/2017] [Indexed: 02/06/2023]
Abstract
Adult hippocampal neurogenesis occurs throughout life and supports healthy brain functions. The production of new neurons decreases with age, and deficiencies in adult neurogenesis are associated with neurodevelopmental and degenerative disease. The rate of neurogenesis is dynamically sensitive to an individual's environmental conditions and experiences, and certain stimuli are known robustly to enhance neurogenesis in rodent models, including voluntary exercise, enriched environment, and electroconvulsive shock. In these models, information about an organism's environment and physiological state are relayed to neurogenic cell types within the hippocampus through a series of tissue and cellular interfaces, ultimately eliciting a neurogenic response from neural stem cells and newborn neurons. Therefore, an understanding of the way that novel genes and proteins act in specific cell types within this circuit-level context is of scientific and therapeutic value. Several well-studied neurotrophic factors have been implicated in environmentally enhanced neurogenesis. This review highlights recently discovered, novel molecular mediators of neurogenesis in response to environmental cues and summarizes the contribution of advanced, large-scale gene expression and function assessment technology to past, present, and future efforts aimed at elucidating cell-type-specific molecular mediators of environmentally enhanced neurogenesis.
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Affiliation(s)
- Brian E Eisinger
- Waisman Center and Department of Neuroscience, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53705, USA
| | - Xinyu Zhao
- Waisman Center and Department of Neuroscience, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53705, USA.
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20
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Pacheco NL, Heaven MR, Holt LM, Crossman DK, Boggio KJ, Shaffer SA, Flint DL, Olsen ML. RNA sequencing and proteomics approaches reveal novel deficits in the cortex of Mecp2-deficient mice, a model for Rett syndrome. Mol Autism 2017; 8:56. [PMID: 29090078 PMCID: PMC5655833 DOI: 10.1186/s13229-017-0174-4] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 10/02/2017] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Rett syndrome (RTT) is an X-linked neurodevelopmental disorder caused by mutations in the transcriptional regulator MeCP2. Much of our understanding of MeCP2 function is derived from transcriptomic studies with the general assumption that alterations in the transcriptome correlate with proteomic changes. Advances in mass spectrometry-based proteomics have facilitated recent interest in the examination of global protein expression to better understand the biology between transcriptional and translational regulation. METHODS We therefore performed the first comprehensive transcriptome-proteome comparison in a RTT mouse model to elucidate RTT pathophysiology, identify potential therapeutic targets, and further our understanding of MeCP2 function. The whole cortex of wild-type and symptomatic RTT male littermates (n = 4 per genotype) were analyzed using RNA-sequencing and data-independent acquisition liquid chromatography tandem mass spectrometry. Ingenuity® Pathway Analysis was used to identify significantly affected pathways in the transcriptomic and proteomic data sets. RESULTS Our results indicate these two "omics" data sets supplement one another. In addition to confirming previous works regarding mRNA expression in Mecp2-deficient animals, the current study identified hundreds of novel protein targets. Several selected protein targets were validated by Western blot analysis. These data indicate RNA metabolism, proteostasis, monoamine metabolism, and cholesterol synthesis are disrupted in the RTT proteome. Hits common to both data sets indicate disrupted cellular metabolism, calcium signaling, protein stability, DNA binding, and cytoskeletal cell structure. Finally, in addition to confirming disrupted pathways and identifying novel hits in neuronal structure and synaptic transmission, our data indicate aberrant myelination, inflammation, and vascular disruption. Intriguingly, there is no evidence of reactive gliosis, but instead, gene, protein, and pathway analysis suggest astrocytic maturation and morphological deficits. CONCLUSIONS This comparative omics analysis supports previous works indicating widespread CNS dysfunction and may serve as a valuable resource for those interested in cellular dysfunction in RTT.
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Affiliation(s)
- Natasha L. Pacheco
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, 1918 University Blvd, Birmingham, AL 35294 USA
| | - Michael R. Heaven
- Vulcan Analytical, LLC, 1500 1st Ave. North, Birmingham, AL 35203 USA
| | - Leanne M. Holt
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, 1918 University Blvd, Birmingham, AL 35294 USA
- School of Neuroscience, Virginia Polytechnic and State University, Life Sciences Building Room 213, 970 Washington St. SW, Blacksburg, VA 24061 USA
| | - David K. Crossman
- UAB Heflin Center for Genomic Science, Department of Genetics, University of Alabama at Birmingham, Kaul 424A, 1720 2nd Ave. South, Birmingham, AL 35294 USA
| | - Kristin J. Boggio
- Proteomics and Mass Spectrometry Facility, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 222 Maple Ave., Fuller Building, Shrewsbury, MA 01545 USA
| | - Scott A. Shaffer
- Proteomics and Mass Spectrometry Facility, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 222 Maple Ave., Fuller Building, Shrewsbury, MA 01545 USA
| | - Daniel L. Flint
- Luxumbra Strategic Research, LLC, 1331 South Eads St, Arlington, VA 22202 USA
| | - Michelle L. Olsen
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, 1918 University Blvd, Birmingham, AL 35294 USA
- School of Neuroscience, Virginia Polytechnic and State University, Life Sciences Building Room 213, 970 Washington St. SW, Blacksburg, VA 24061 USA
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21
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Gómez C, Jimeno D, Fernández-Medarde A, García-Navas R, Calzada N, Santos E. Ras-GRF2 regulates nestin-positive stem cell density and onset of differentiation during adult neurogenesis in the mouse dentate gyrus. Mol Cell Neurosci 2017; 85:127-147. [PMID: 28966131 DOI: 10.1016/j.mcn.2017.09.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 09/11/2017] [Accepted: 09/17/2017] [Indexed: 12/12/2022] Open
Abstract
Various parameters of neurogenesis were analyzed in parallel in the two neurogenic areas (the Dentate Gyrus[DG] and the Subventricular Zone[SVZ]/Rostral Migratory Stream[RMS]/Main Olfactory Bulb[MOB] neurogenic system) of adult WT and KO mouse strains for the Ras-GRF1/2 genes (Ras-GRF1-KO, Ras-GRF2-KO, Ras-GRF1/2-DKO). Significantly reduced numbers of doublecortin[DCX]-positive cells were specifically observed in the DG, but not the SVZ/RMS/MOB neurogenic region, of Ras-GRF2-KO and Ras-GRF1/2-DKO mice indicating that this novel Ras-GRF2-dependent phenotype is spatially restricted to a specific neurogenic area. Consistent with a role of CREB as mediator of Ras-GRF2 function in neurogenesis, the density of p-CREB-positive cells was also specifically reduced in all neurogenic regions of Ras-GRF2-KO and DKO mice. Similar levels of early neurogenic proliferation markers (Ki67, BrdU) were observed in all different Ras-GRF genotypes analyzed but significantly elevated levels of nestin-immunolabel, particularly of undifferentiated, highly ramified, A-type nestin-positive neurons were specifically detected in the DG but not the SVZ/RMS/MOB of Ras-GRF2-KO and DKO mice. Together with assays of other neurogenic markers (GFAP, Sox2, Tuj1, NeuN), these observations suggest that the deficit of DCX/p-CREB-positive cells in the DG of Ras-GRF2-depleted mice does not involve impaired neuronal proliferation but rather delayed transition from the stem cell stage to the differentiation stages of the neurogenic process. This model is also supported by functional analyses of DG-derived neurosphere cultures and transcriptional characterization of the neurogenic areas of mice of all relevant Ras-GRF genotypes suggesting that the neurogenic role of Ras-GRF2 is exerted in a cell-autonomous manner through a specific transcriptional program.
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Affiliation(s)
- Carmela Gómez
- Centro de Investigación del Cáncer-Instituto de Biología Molecular y Celular del Cáncer (CSIC- Universidad de Salamanca) and CIBERONC, 37007 Salamanca, Spain
| | - David Jimeno
- Centro de Investigación del Cáncer-Instituto de Biología Molecular y Celular del Cáncer (CSIC- Universidad de Salamanca) and CIBERONC, 37007 Salamanca, Spain
| | - Alberto Fernández-Medarde
- Centro de Investigación del Cáncer-Instituto de Biología Molecular y Celular del Cáncer (CSIC- Universidad de Salamanca) and CIBERONC, 37007 Salamanca, Spain
| | - Rósula García-Navas
- Centro de Investigación del Cáncer-Instituto de Biología Molecular y Celular del Cáncer (CSIC- Universidad de Salamanca) and CIBERONC, 37007 Salamanca, Spain
| | - Nuria Calzada
- Centro de Investigación del Cáncer-Instituto de Biología Molecular y Celular del Cáncer (CSIC- Universidad de Salamanca) and CIBERONC, 37007 Salamanca, Spain
| | - Eugenio Santos
- Centro de Investigación del Cáncer-Instituto de Biología Molecular y Celular del Cáncer (CSIC- Universidad de Salamanca) and CIBERONC, 37007 Salamanca, Spain.
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Soluble Epoxide Hydrolase Inhibitor and 14,15-Epoxyeicosatrienoic Acid-Facilitated Long-Term Potentiation through cAMP and CaMKII in the Hippocampus. Neural Plast 2017; 2017:3467805. [PMID: 29138698 PMCID: PMC5613711 DOI: 10.1155/2017/3467805] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 07/03/2017] [Accepted: 07/27/2017] [Indexed: 01/18/2023] Open
Abstract
Epoxyeicosatrienoic acids (EETs) are derived from arachidonic acid and metabolized by soluble epoxide hydrolase (sEH). The role of EETs in synaptic function in the central nervous system is still largely unknown. We found that pharmacological inhibition of sEH to stabilize endogenous EETs and exogenous 14,15-EET significantly increased the field excitatory postsynaptic potential (fEPSP) response in the CA1 area of the hippocampus, while additionally enhancing high-frequency stimulation- (HFS-) induced long-term potentiation (LTP) and forskolin- (FSK-) induced LTP. sEH inhibitor (sEHI) N-[1-(oxopropyl)-4-piperidinyl]-N'-[4-(trifluoromethoxy) phenyl)-urea (TPPU) and exogenous 14,15-EET increased HFS-LTP, which could be blocked by an N-methyl-D-aspartate (NMDA) receptor subunit NR2B antagonist. TPPU- or 14,15-EET-facilitated FSK-mediated LTP can be potentiated by an A1 adenosine receptor antagonist and a phosphodiesterase inhibitor, but is prevented by a cAMP-dependent protein kinase (PKA) inhibitor. sEHI and 14,15-EET upregulated the activation of extracellular signal-regulated kinases (ERKs) and Ca2+/calmodulin- (CaM-) dependent protein kinase II (CaMKII). Phosphorylation of synaptic receptors NR2B and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluR1 was increased by TPPU and 14,15-EET administration. These results indicated that EETs increased NMDAR- and FSK-mediated synaptic potentiation via the AC-cAMP-PKA signaling cascade and upregulated the ERKs and CaMKII, resulting in increased phosphorylation of NR2B and GluR1 in the hippocampus.
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Abstract
The main characteristic of alcohol use disorder is the consumption of large quantities of alcohol despite the negative consequences. The transition from the moderate use of alcohol to excessive, uncontrolled alcohol consumption results from neuroadaptations that cause aberrant motivational learning and memory processes. Here, we examine studies that have combined molecular and behavioural approaches in rodents to elucidate the molecular mechanisms that keep the social intake of alcohol in check, which we term 'stop pathways', and the neuroadaptations that underlie the transition from moderate to uncontrolled, excessive alcohol intake, which we term 'go pathways'. We also discuss post-transcriptional, genetic and epigenetic alterations that underlie both types of pathways.
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Affiliation(s)
- Dorit Ron
- Corresponding author: Dorit Ron, 675 Nelson Rising Lane, BOX 0663, San Francisco, CA 94143-0663,
| | - Segev Barak
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94143, USA
- School of Psychological Sciences and Sagol School of Neuroscience, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
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Jimeno D, Gómez C, Calzada N, de la Villa P, Lillo C, Santos E. RASGRF2 controls nuclear migration in postnatal retinal cone photoreceptors. J Cell Sci 2016; 129:729-42. [PMID: 26743081 DOI: 10.1242/jcs.180919] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 12/29/2015] [Indexed: 02/04/2023] Open
Abstract
Detailed immunocytochemical analyses comparing wild-type (WT), GRF1-knockout (KO), GRF2-KO and GRF1/2 double-knockout (DKO) mouse retinas uncovered the specific accumulation of misplaced, 'ectopic' cone photoreceptor nuclei in the photoreceptor segment (PS) area of retinas from GRF2-KO and GRF1/2-DKO, but not of WT or GRF1-KO mice. Localization of ectopic nuclei in the PS area of GRF2-depleted retinas occurred postnatally and peaked between postnatal day (P)11 and P15. Mechanistically, the generation of this phenotype involved disruption of the outer limiting membrane and intrusion into the PS layer by cone nuclei displaying significant perinuclear accumulation of signaling molecules known to participate in nuclear migration and cytoskeletal reorganization, such as PAR3, PAR6 and activated, phosphorylated forms of PAK, MLC2 and VASP. Electroretinographic recordings showed specific impairment of cone-mediated retinal function in GRF2-KO and GRF1/2-DKO retinas compared with WT controls. These data identify defective cone nuclear migration as a novel phenotype in mouse retinas lacking GRF2 and support a crucial role of GRF2 in control of the nuclear migration processes required for proper postnatal development and function of retinal cone photoreceptors.
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Affiliation(s)
- David Jimeno
- Centro de Investigación del Cáncer-Instituto de Biología Molecular y Celular del Cáncer (CSIC - Universidad de Salamanca), Salamanca 37007, Spain
| | - Carmela Gómez
- Centro de Investigación del Cáncer-Instituto de Biología Molecular y Celular del Cáncer (CSIC - Universidad de Salamanca), Salamanca 37007, Spain
| | - Nuria Calzada
- Centro de Investigación del Cáncer-Instituto de Biología Molecular y Celular del Cáncer (CSIC - Universidad de Salamanca), Salamanca 37007, Spain
| | - Pedro de la Villa
- Departamento de Fisiología, Universidad Alcalá, Alcalá de Henares 28871, Spain, Spain
| | | | - Eugenio Santos
- Centro de Investigación del Cáncer-Instituto de Biología Molecular y Celular del Cáncer (CSIC - Universidad de Salamanca), Salamanca 37007, Spain
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Uzturk BG, Jin SX, Rubin B, Bartolome C, Feig LA. RasGRF1 regulates the hypothalamic-pituitary-adrenal axis specifically in early-adolescent female mice. J Endocrinol 2015; 227:1-12. [PMID: 26246084 PMCID: PMC4560991 DOI: 10.1530/joe-15-0304] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/05/2015] [Indexed: 01/03/2023]
Abstract
Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis has been implicated in the induction and prolongation of a variety of psychiatric disorders. As such, much effort has been made to understand the molecular mechanisms involved in its control. However, the vast majority of the studies on the HPA axis have used adult animals, and among these the majority has used males. Here we show that in knockout mice lacking the guanine nucleotide exchange factor, RasGRF1, habituation to 30 min/day of restraint stress is markedly accelerated, such that these mice do not display elevated corticosterone levels or enhanced locomotion after 7 days of stress exposure, like WT mice do. Strikingly, this phenotype is present in early-adolescent female RasGRF1 knockout mice, but not in their early-adolescent male, mid-adolescent female, adult female or adult male counterparts. Moreover, not only is there a clear response to restraint stress in early-adolescent female RasGRF1 knockout mice, their response after one, three and five exposures is magnified approximately threefold compared to WT mice. These findings imply that distinct mechanisms exist to regulate the HPA axis in early-adolescent females that involves RasGRF1. A full understanding of how RasGRF1 controls the HPA axis response to stress may be required to design effective strategies to combat stress-associated psychiatric disorders initiated in young females.
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Affiliation(s)
- Belkis Gizem Uzturk
- Sackler School of Graduate Biomedical SciencesDepartments of DevelopmentalMolecular and Chemical BiologyIntegrated Physiology and PathobiologyTufts University School of Medicine, Boston, Massachusetts 02111, USA
| | - Shan-Xue Jin
- Sackler School of Graduate Biomedical SciencesDepartments of DevelopmentalMolecular and Chemical BiologyIntegrated Physiology and PathobiologyTufts University School of Medicine, Boston, Massachusetts 02111, USA
| | - Beverly Rubin
- Sackler School of Graduate Biomedical SciencesDepartments of DevelopmentalMolecular and Chemical BiologyIntegrated Physiology and PathobiologyTufts University School of Medicine, Boston, Massachusetts 02111, USA Sackler School of Graduate Biomedical SciencesDepartments of DevelopmentalMolecular and Chemical BiologyIntegrated Physiology and PathobiologyTufts University School of Medicine, Boston, Massachusetts 02111, USA
| | - Christopher Bartolome
- Sackler School of Graduate Biomedical SciencesDepartments of DevelopmentalMolecular and Chemical BiologyIntegrated Physiology and PathobiologyTufts University School of Medicine, Boston, Massachusetts 02111, USA
| | - Larry A Feig
- Sackler School of Graduate Biomedical SciencesDepartments of DevelopmentalMolecular and Chemical BiologyIntegrated Physiology and PathobiologyTufts University School of Medicine, Boston, Massachusetts 02111, USA Sackler School of Graduate Biomedical SciencesDepartments of DevelopmentalMolecular and Chemical BiologyIntegrated Physiology and PathobiologyTufts University School of Medicine, Boston, Massachusetts 02111, USA
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Regulating Rac in the nervous system: molecular function and disease implication of Rac GEFs and GAPs. BIOMED RESEARCH INTERNATIONAL 2015; 2015:632450. [PMID: 25879033 PMCID: PMC4388020 DOI: 10.1155/2015/632450] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 03/06/2015] [Indexed: 12/11/2022]
Abstract
Rho family GTPases, including RhoA, Rac1, and Cdc42 as the most studied members, are master regulators of actin cytoskeletal organization. Rho GTPases control various aspects of the nervous system and are associated with a number of neuropsychiatric and neurodegenerative diseases. The activity of Rho GTPases is controlled by two families of regulators, guanine nucleotide exchange factors (GEFs) as the activators and GTPase-activating proteins (GAPs) as the inhibitors. Through coordinated regulation by GEFs and GAPs, Rho GTPases act as converging signaling molecules that convey different upstream signals in the nervous system. So far, more than 70 members of either GEFs or GAPs of Rho GTPases have been identified in mammals, but only a small subset of them have well-known functions. Thus, characterization of important GEFs and GAPs in the nervous system is crucial for the understanding of spatiotemporal dynamics of Rho GTPase activity in different neuronal functions. In this review, we summarize the current understanding of GEFs and GAPs for Rac1, with emphasis on the molecular function and disease implication of these regulators in the nervous system.
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Manyes L, Arribas M, Gomez C, Calzada N, Fernandez-Medarde A, Santos E. Transcriptional profiling reveals functional links between RasGrf1 and Pttg1 in pancreatic beta cells. BMC Genomics 2014; 15:1019. [PMID: 25421944 PMCID: PMC4301450 DOI: 10.1186/1471-2164-15-1019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 11/06/2014] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Our prior characterization of RasGrf1 deficient mice uncovered significant defects in pancreatic islet count and size as well as beta cell development and signaling function, raising question about the mechanisms linking RasGrf1 to the generation of those "pancreatic" phenotypes. RESULTS Here, we compared the transcriptional profile of highly purified pancreatic islets from RasGrf1 KO mice to that of WT control animals using commercial oligonucleotide microarrays. RasGrf1 elimination resulted in differential gene expression of numerous components of MAPK- and Calcium-signaling pathways, suggesting a relevant contribution of this GEF to modulation of cellular signaling in the cell lineages integrating the pancreatic islets. Whereas the overall transcriptional profile of pancreatic islets was highly specific in comparison to other organs of the same KO mice, a significant specific repression of Pttg1 was a common transcriptional alteration shared with other tissues of neuroectodermal origin. This observation, together with the remarkable pancreatic phenotypic similarities between RasGrf1 KO and Pttg1 KO mice suggested the possibility of proximal functional regulatory links between RasGrf1 and Pttg1 in pancreatic cell lineages expressing these proteins.Analysis of the mPttg1 promoter region identified specific recognition sites for numerous transcription factors which were also found to be differentially expressed in RasGrf1 KO pancreatic islets and are known to be relevant for Ras-ERK signaling as well as beta cell function. Reporter luciferase assays in BT3 insulinoma cells demonstrated the ability of RasGrf1 to modulate mPttg1 promoter activity through ERK-mediated signals. Analysis of the phenotypic interplay between RasGrf1 and Pttg1 in double knockout RasGrf1/Pttg1 mice showed that combined elimination of the two loci resulted in dramatically reduced values of islet and beta cell count and glucose homeostasis function which neared those measured in single Pttg1 KO mice and were significantly lower than those observed in individual RasGrf1 KO mice. CONCLUSIONS The specific transcriptional profile and signaling behavior of RasgGrf1 KO pancreatic islets, together with the dominance of Pttg1 over RasGrf1 with regards to the generation of these phenotypes in mouse pancreas, suggest that RasGrf1 is an important upstream component of signal transduction pathways regulating Pttg1 expression and controlling beta cell development and physiological responses.
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Affiliation(s)
| | | | | | | | - Alberto Fernandez-Medarde
- Centro de Investigación del Cáncer, IBMCC (CSIC-USAL), University of Salamanca, Campus Unamuno, 37007 Salamanca, Spain.
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Darcy MJ, Trouche S, Jin SX, Feig LA. Age-dependent role for Ras-GRF1 in the late stages of adult neurogenesis in the dentate gyrus. Hippocampus 2014; 24:315-25. [PMID: 24174283 DOI: 10.1002/hipo.22225] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 10/08/2013] [Accepted: 10/22/2013] [Indexed: 01/08/2023]
Abstract
The dentate gyrus of the hippocampus plays a pivotal role in pattern separation, a process required for the behavioral task of contextual discrimination. One unique feature of the dentate gyrus that contributes to pattern separation is adult neurogenesis, where newly born neurons play a distinct role in neuronal circuitry. Moreover,the function of neurogenesis in this brain region differs in adolescent and adult mice. The signaling mechanisms that differentially regulate the distinct steps of adult neurogenesis in adolescence and adulthood remain poorly understood. We used mice lacking RASGRF1(GRF1), a calcium-dependent exchange factor that regulates synaptic plasticity and participates in contextual discrimination performed by mice, to test whether GRF1 plays a role in adult neurogenesis.We show Grf1 knockout mice begin to display a defect in neurogenesis at the onset of adulthood (~2 months of age), when wild-type mice first acquire the ability to distinguish between closely related contexts. At this age, young hippocampal neurons in Grf1 knockout mice display severely reduced dendritic arborization. By 3 months of age, new neuron survival is also impaired. BrdU labeling of new neurons in 2-month-old Grf1 knockout mice shows they begin to display reduced survival between 2 and 3 weeks after birth, just as new neurons begin to develop complex dendritic morphology and transition into using glutamatergic excitatory input. Interestingly, GRF1 expression appears in new neurons at the developmental stage when GRF1 loss begins to effect neuronal function. In addition, we induced a similar loss of new hippocampal neurons by knocking down expression of GRF1 solely in new neurons by injecting retrovirus that express shRNA against GRF1 into the dentate gyrus. Together, these findings show that GRF1 expressed in new neurons promotes late stages of adult neurogenesis. Overall our findings show GRF1 to be an age-dependent regulator of adult hippocampal neurogenesis, which contributes to ability of mice to distinguish closely related contexts.
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Darcy MJ, Jin SX, Feig LA. R-Ras contributes to LTP and contextual discrimination. Neuroscience 2014; 277:334-42. [PMID: 25043327 DOI: 10.1016/j.neuroscience.2014.07.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 07/07/2014] [Accepted: 07/08/2014] [Indexed: 11/17/2022]
Abstract
The ability to discriminate between closely related contexts is a specific form of hippocampal-dependent learning that may be impaired in certain neurodegenerative disorders such as Alzheimer's and Down Syndrome. However, signaling pathways regulating this form of learning are poorly understood. Previous studies have shown that the calcium-dependent exchange factor Ras-GRF1, an activator of Rac, Ras and R-Ras GTPases, is important for this form of learning and memory. Moreover, the ability to discriminate contexts was linked to the ability of Ras-GRF1 to promote high-frequency stimulation long-term potentiation (HFS-LTP) via the activation of p38 Map kinase. Here, we show that R-Ras is involved in this form of learning by using virally-delivered miRNAs targeting R-Ras into the CA1 region of the dorsal hippocampus and observing impaired contextual discrimination. Like the loss of GRF1, knockdown of R-Ras in the CA1 also impairs the induction of HFS-LTP and p38 Map kinase. Nevertheless, experiments indicate that this involvement of R-Ras in HFS-LTP that is required for contextual discrimination is independent of Ras-GRF1. Thus, R-Ras is a novel regulator of a form of hippocampal-dependent LTP as well as learning and memory that is affected in certain forms of neurodegenerative diseases.
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Affiliation(s)
- M J Darcy
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA, United States
| | - S-X Jin
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA, United States
| | - L A Feig
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA, United States; Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States.
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Darcy MJ, Trouche S, Jin SX, Feig LA. Ras-GRF2 mediates long-term potentiation, survival, and response to an enriched environment of newborn neurons in the hippocampus. Hippocampus 2014; 24:1317-29. [PMID: 24894950 DOI: 10.1002/hipo.22313] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2014] [Indexed: 01/04/2023]
Abstract
Hippocampal adult neurogenesis contributes to key functions of the dentate gyrus (DG), including contextual discrimination. This is due, at least in part, to the unique form of plasticity that new neurons display at a specific stage of their development when compared with the surrounding principal neurons. In addition, the contribution that newborn neurons make to dentate function can be enhanced by an increase in their numbers induced by a stimulating environment. However, signaling mechanisms that regulate these properties of newborn neurons are poorly understood. Here, we show that Ras-GRF2 (GRF2), a calcium-regulated exchange factor that can activate Ras and Rac GTPases, contributes to both of these properties of newborn neurons. Using Ras-GRF2 knockout mice and wild-type mice stereotactically injected with retrovirus containing shRNA against the exchange factor, we demonstrate that GRF2 promotes the survival of newborn neurons of the DG at approximately 1-2 weeks after their birth. GRF2 also controls the distinct form of long-term potentiation that is characteristic of new neurons of the hippocampus through its effector Erk MAP kinase. Moreover, the enhancement of neuron survival that occurs after mice are exposed to an enriched environment also involves GRF2 function. Consistent with these observations, GRF2 knockout mice display defective contextual discrimination. Overall, these findings indicate that GRF2 regulates both the basal level and environmentally induced increase of newborn neuron survival, as well as in the induction of a distinct form of synaptic plasticity of newborn neurons that contributes to distinct features of hippocampus-derived learning and memory.
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Affiliation(s)
- Michael J Darcy
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts
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31
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Fan X, Jin WY, Wang YT. The NMDA receptor complex: a multifunctional machine at the glutamatergic synapse. Front Cell Neurosci 2014; 8:160. [PMID: 24959120 PMCID: PMC4051310 DOI: 10.3389/fncel.2014.00160] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Accepted: 05/26/2014] [Indexed: 01/11/2023] Open
Abstract
The N-methyl-D-aspartate receptors (NMDARs) are part of a large multiprotein complex at the glutamatergic synapse. The assembly of NMDARs with synaptic proteins offers a means to regulate NMDAR channel properties and receptor trafficking, and couples NMDAR activation to distinct intracellular signaling pathways, thus contributing to the versatility of NMDAR functions. Receptor-protein interactions at the synapse provide a dynamic and powerful mechanism for regulating synaptic efficacy, but can also contribute to NMDAR overactivation-induced excitotoxicity and cellular damage under pathological conditions. An emerging concept is that by understanding the mechanisms and functions of disease-specific protein-protein interactions in the NMDAR complex, we may be able to develop novel therapies based on protein-NMDAR interactions for the treatment of brain diseases in which NMDAR dysfunction is at the root of their pathogenesis.
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Affiliation(s)
- Xuelai Fan
- Brain Research Centre and Department of Medicine, Vancouver Coastal Health Research Institute, University of British Columbia Vancouver, BC, Canada
| | - Wu Yang Jin
- Brain Research Centre and Department of Medicine, Vancouver Coastal Health Research Institute, University of British Columbia Vancouver, BC, Canada
| | - Yu Tian Wang
- Brain Research Centre and Department of Medicine, Vancouver Coastal Health Research Institute, University of British Columbia Vancouver, BC, Canada
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Jin SX, Bartolome C, Arai JA, Hoffman L, Uzturk BG, Kumar-Singh R, Waxham MN, Feig LA. Domain contributions to signaling specificity differences between Ras-guanine nucleotide releasing factor (Ras-GRF) 1 and Ras-GRF2. J Biol Chem 2014; 289:16551-64. [PMID: 24755227 DOI: 10.1074/jbc.m114.557959] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ras-GRF1 (GRF1) and Ras-GRF2 (GRF2) constitute a family of similar calcium sensors that regulate synaptic plasticity. They are both guanine exchange factors that contain a very similar set of functional domains, including N-terminal pleckstrin homology, coiled-coil, and calmodulin-binding IQ domains and C-terminal Dbl homology Rac-activating domains, Ras-exchange motifs, and CDC25 Ras-activating domains. Nevertheless, they regulate different forms of synaptic plasticity. Although both GRF proteins transduce calcium signals emanating from NMDA-type glutamate receptors in the CA1 region of the hippocampus, GRF1 promotes LTD, whereas GRF2 promotes θ-burst stimulation-induced LTP (TBS-LTP). GRF1 can also mediate high frequency stimulation-induced LTP (HFS-LTP) in mice over 2-months of age, which involves calcium-permeable AMPA-type glutamate receptors. To add to our understanding of how proteins with similar domains can have different functions, WT and various chimeras between GRF1 and GRF2 proteins were tested for their abilities to reconstitute defective LTP and/or LTD in the CA1 hippocampus of Grf1/Grf2 double knock-out mice. These studies revealed a critical role for the GRF2 CDC25 domain in the induction of TBS-LTP by GRF proteins. In contrast, the N-terminal pleckstrin homology and/or coiled-coil domains of GRF1 are key to the induction of HFS-LTP by GRF proteins. Finally, the IQ motif of GRF1 determines whether a GRF protein can induce LTD. Overall, these findings show that for the three forms of synaptic plasticity that are regulated by GRF proteins in the CA1 hippocampus, specificity is encoded in only one or two domains, and a different set of domains for each form of synaptic plasticity.
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Affiliation(s)
- Shan-Xue Jin
- From the Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts 02111 and
| | - Christopher Bartolome
- From the Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts 02111 and
| | - Junko A Arai
- From the Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts 02111 and
| | - Laurel Hoffman
- the Department of Neurobiology and Anatomy, University of Texas, Houston, Texas
| | - B Gizem Uzturk
- From the Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts 02111 and
| | - Rajendra Kumar-Singh
- From the Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts 02111 and
| | - M Neal Waxham
- the Department of Neurobiology and Anatomy, University of Texas, Houston, Texas
| | - Larry A Feig
- From the Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts 02111 and
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Ma X, Espana-Serrano L, Kim WJ, Thayele Purayil H, Nie Z, Daaka Y. βArrestin1 regulates the guanine nucleotide exchange factor RasGRF2 expression and the small GTPase Rac-mediated formation of membrane protrusion and cell motility. J Biol Chem 2014; 289:13638-50. [PMID: 24692549 DOI: 10.1074/jbc.m113.511360] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
βArrestin proteins shuttle between the cytosol and nucleus and have been shown to regulate G protein-coupled receptor signaling, actin remodeling, and gene expression. Here, we tested the hypothesis that βarrestin1 regulates actin remodeling and cell migration through the small GTPase Rac. Depletion of βarrestin1 promotes Rac activation, leading to the formation of multipolar protrusions and increased cell circularity, and overexpression of a dominant negative form of Rac reverses these morphological changes. Small interfering RNA library screen identifies RasGRF2 as a target of βarrestin1. RasGRF2 gene and protein expression levels are elevated following depletion of βarrestin1, and the consequent activation of Rac results in dephosphorylation of cofilin that can promote actin polymerization and formation of multipolar protrusions, thereby retarding cell migration and invasion. Together, these results suggest that βarrestin1 regulates rasgrf2 gene expression and Rac activation to affect membrane protrusion and cell migration and invasion.
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Affiliation(s)
- Xiaojie Ma
- From the Department of Anatomy and Cell Biology, University of Florida College of Medicine, Gainesville, Florida 32610
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Abstract
Learning and memory require the formation of new neural networks in the brain. A key mechanism underlying this process is synaptic plasticity at excitatory synapses, which connect neurons into networks. Excitatory synaptic transmission happens when glutamate, the excitatory neurotransmitter, activates receptors on the postsynaptic neuron. Synaptic plasticity is a higher-level process in which the strength of excitatory synapses is altered in response to the pattern of activity at the synapse. It is initiated in the postsynaptic compartment, where the precise pattern of influx of calcium through activated glutamate receptors leads either to the addition of new receptors and enlargement of the synapse (long-term potentiation) or the removal of receptors and shrinkage of the synapse (long-term depression). Calcium/calmodulin-regulated enzymes and small GTPases collaborate to control this highly tuned mechanism.
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Affiliation(s)
- Mary B Kennedy
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125
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Roussotte FF, Gutman BA, Hibar DP, Jahanshad N, Madsen SK, Jack CR, Weiner MW, Thompson PM. A single nucleotide polymorphism associated with reduced alcohol intake in the RASGRF2 gene predicts larger cortical volumes but faster longitudinal ventricular expansion in the elderly. Front Aging Neurosci 2013; 5:93. [PMID: 24409144 PMCID: PMC3867747 DOI: 10.3389/fnagi.2013.00093] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 11/30/2013] [Indexed: 11/23/2022] Open
Abstract
A recent genome-wide association meta-analysis showed a suggestive association between alcohol intake in humans and a common single nucleotide polymorphism in the ras-specific guanine nucleotide releasing factor 2 gene. Here, we tested whether this variant – associated with lower alcohol consumption – showed associations with brain structure and longitudinal ventricular expansion over time, across two independent elderly cohorts, totaling 1,032 subjects. We first examined a large sample of 738 elderly participants with neuroimaging and genetic data from the Alzheimer’s Disease Neuroimaging Initiative (ADNI1). Then, we assessed the generalizability of the findings by testing this polymorphism in a replication sample of 294 elderly subjects from a continuation of the first ADNI project (ADNI2) to minimize the risk of reporting false positive results. The minor allele – previously linked with lower alcohol intake – was associated with larger volumes in various cortical regions, notably the medial prefrontal cortex and cingulate gyrus in both cohorts. Intriguingly, the same allele also predicted faster ventricular expansion rates in the ADNI1 cohort at 1- and 2-year follow up. Despite a lack of alcohol consumption data in this study cohort, these findings, combined with earlier functional imaging investigations of the same gene, suggest the existence of reciprocal interactions between genes, brain, and drinking behavior.
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Affiliation(s)
- Florence F Roussotte
- Imaging Genetics Center, University of Southern California Los Angeles, CA, USA ; Departments of Neurology and Psychiatry, David Geffen School of Medicine at University of California Los Angeles Los Angeles, CA, USA
| | - Boris A Gutman
- Imaging Genetics Center, University of Southern California Los Angeles, CA, USA
| | - Derrek P Hibar
- Imaging Genetics Center, University of Southern California Los Angeles, CA, USA
| | - Neda Jahanshad
- Imaging Genetics Center, University of Southern California Los Angeles, CA, USA
| | - Sarah K Madsen
- Imaging Genetics Center, University of Southern California Los Angeles, CA, USA
| | | | - Michael W Weiner
- Departments of Radiology, Medicine, Psychiatry, University of California San Francisco San Francisco, CA, USA ; Department of Veterans Affairs Medical Center San Francisco, CA, USA
| | - Paul M Thompson
- Imaging Genetics Center, University of Southern California Los Angeles, CA, USA ; Departments of Neurology and Psychiatry, David Geffen School of Medicine at University of California Los Angeles Los Angeles, CA, USA ; Departments of Neurology, Psychiatry, Pediatrics, Engineering, Radiology, and Ophthalmology, Keck University of Southern California School of Medicine, University of Southern California , Los Angeles, CA, USA
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Cestari V, Rossi-Arnaud C, Saraulli D, Costanzi M. The MAP(K) of fear: from memory consolidation to memory extinction. Brain Res Bull 2013; 105:8-16. [PMID: 24080449 DOI: 10.1016/j.brainresbull.2013.09.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 09/20/2013] [Accepted: 09/21/2013] [Indexed: 11/25/2022]
Abstract
The highly conserved mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling cascade is involved in several intracellular processes ranging from cell differentiation to proliferation, as well as in synaptic plasticity. In the last two decades, the role of MAPK/ERK in long-term memory formation in mammals, particularly in fear-related memories, has been extensively investigated. In this review we describe knowledge advancement on the role of MAPK/ERK in orchestrating the intracellular processes that lead to the consolidation, reconsolidation and extinction of fear memories. In doing so, we report studies in which the specific role of MAP/ERK in switching from memory formation to memory erasure has been suggested. The possibility to target MAPK/ERK in developing and/or refining pharmacological approaches to treat psychiatric disorders in which fear regulation is defective has also been envisaged.
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Affiliation(s)
- Vincenzo Cestari
- Institute of Cellular Biology and Neurobiology, National Research Council and Fondazione Santa Lucia, via del Fosso di Fiorano 64, 00143 Rome, Italy; Department of Psychology and "Daniel Bovet" Center, Sapienza University of Rome, via dei Marsi 78, 00185 Rome, Italy.
| | - Clelia Rossi-Arnaud
- Department of Psychology, Sapienza University of Rome, via dei Marsi 78, 00185 Rome, Italy
| | - Daniele Saraulli
- Institute of Cellular Biology and Neurobiology, National Research Council and Fondazione Santa Lucia, via del Fosso di Fiorano 64, 00143 Rome, Italy; Department of Psychology, Sapienza University of Rome, via dei Marsi 78, 00185 Rome, Italy
| | - Marco Costanzi
- Institute of Cellular Biology and Neurobiology, National Research Council and Fondazione Santa Lucia, via del Fosso di Fiorano 64, 00143 Rome, Italy; Department of Human Sciences, LUMSA University, p.zza delle Vaschette 101, 00193 Rome, Italy
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Inositol kinase and its product accelerate wound healing by modulating calcium levels, Rho GTPases, and F-actin assembly. Proc Natl Acad Sci U S A 2013; 110:11029-34. [PMID: 23776233 DOI: 10.1073/pnas.1217308110] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Wound healing is essential for survival. We took advantage of the Xenopus embryo, which exhibits remarkable capacities to repair wounds quickly and efficiently, to investigate the mechanisms responsible for wound healing. Previous work has shown that injury triggers a rapid calcium response, followed by the activation of Ras homolog (Rho) family guanosine triphosphatases (GTPases), which regulate the formation and contraction of an F-actin purse string around the wound margin. How these processes are coordinated following wounding remained unclear. Here we show that inositol-trisphosphate 3-kinase B (Itpkb) via its enzymatic product inositol 1,3,4,5-tetrakisphosphate (InsP4) plays an essential role during wound healing by modulating the activity of Rho family GTPases and F-actin ring assembly. Furthermore, we show that Itpkb and InsP4 modulate the speed of the calcium wave, which propagates from the site of injury into neighboring uninjured cells. Strikingly, both overexpression of itpkb and exogenous application of InsP4 accelerate the speed of wound closure, a finding that has potential implications in our quest to find treatments that improve wound healing in patients with acute or chronic wounds.
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Jin SX, Arai J, Tian X, Kumar-Singh R, Feig LA. Acquisition of contextual discrimination involves the appearance of a RAS-GRF1/p38 mitogen-activated protein (MAP) kinase-mediated signaling pathway that promotes long term potentiation (LTP). J Biol Chem 2013; 288:21703-13. [PMID: 23766509 DOI: 10.1074/jbc.m113.471904] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
RAS-GRF1 is a guanine nucleotide exchange factor with the ability to activate RAS and RAC GTPases in response to elevated calcium levels. We previously showed that beginning at 1 month of age, RAS-GRF1 mediates NMDA-type glutamate receptor (NMDAR)-induction of long term depression in the CA1 region of the hippocampus of mice. Here we show that beginning at 2 months of age, when mice first acquire the ability to discriminate between closely related contexts, RAS-GRF1 begins to contribute to the induction of long term potentiation (LTP) in the CA1 hippocampus by mediating the action of calcium-permeable, AMPA-type glutamate receptors (CP-AMPARs). Surprisingly, LTP induction by CP-AMPARs through RAS-GRF1 occurs via activation of p38 MAP kinase rather than ERK MAP kinase, which has more frequently been linked to LTP. Moreover, contextual discrimination is blocked by knockdown of Ras-Grf1 expression specifically in the CA1 hippocampus, infusion of a p38 MAP kinase inhibitor into the CA1 hippocampus, or the injection of an inhibitor of CP-AMPARs. These findings implicate the CA1 hippocampus in the developmentally dependent capacity to distinguish closely related contexts through the appearance of a novel LTP-supporting signaling pathway.
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Affiliation(s)
- Shan-Xue Jin
- Department of Biochemistry, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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Miller MB, Yan Y, Eipper BA, Mains RE. Neuronal Rho GEFs in synaptic physiology and behavior. Neuroscientist 2013; 19:255-73. [PMID: 23401188 DOI: 10.1177/1073858413475486] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In the mammalian brain, the majority of excitatory synapses are housed in micron-sized dendritic protrusions called spines, which can undergo rapid changes in shape and number in response to increased or decreased synaptic activity. These dynamic alterations in dendritic spines require precise control of the actin cytoskeleton. Within spines, multidomain Rho guanine nucleotide exchange factors (Rho GEFs) coordinate activation of their target Rho GTPases by a variety of pathways. In this review, we focus on the handful of disease-related Rho GEFs (Kalirin; Trio; Tiam1; P-Rex1,2; RasGRF1,2; Collybistin) localized at synapses and known to affect electrophysiology, spine morphology, and animal behavior. The goal is to integrate structure/function studies with measurements of synaptic function and behavioral phenotypes in animal models.
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Affiliation(s)
- Megan B Miller
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT 06030-3401, USA
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The small G protein H-Ras in the mesolimbic system is a molecular gateway to alcohol-seeking and excessive drinking behaviors. J Neurosci 2013; 32:15849-58. [PMID: 23136424 DOI: 10.1523/jneurosci.2846-12.2012] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Uncontrolled consumption of alcohol is a hallmark of alcohol abuse disorders; however, the central molecular mechanisms underlying excessive alcohol consumption are still unclear. Here, we report that the GTP binding protein, H-Ras in the nucleus accumbens (NAc) plays a key role in neuroadaptations that underlie excessive alcohol-drinking behaviors. Specifically, acute (15 min) systemic administration of alcohol (2.5 g/kg) leads to the activation of H-Ras in the NAc of mice, which is observed even 24 h later. Similarly, rat operant self-administration of alcohol (20%) also results in the activation of H-Ras in the NAc. Using the same procedures, we provide evidence suggesting that the exchange factor GRF1 is upstream of H-Ras activation by alcohol. Importantly, we show that infection of mice NAc with lentivirus expressing a short hairpin RNA that targets the H-Ras gene produces a significant reduction of voluntary consumption of 20% alcohol. In contrast, knockdown of H-Ras in the NAc of mice did not alter water, quinine, and saccharin intake. Furthermore, using two-bottle choice and operant self-administration procedures, we show that inhibiting H-Ras activity by intra-NAc infusion of the farnesyltransferase inhibitor, FTI-276, produced a robust decrease of rats' alcohol drinking; however, sucrose consumption was unaltered. Finally, intra-NAc infusion of FTI-276 also resulted in an attenuation of seeking for alcohol. Together, these results position H-Ras as a central molecular mediator of alcohol's actions within the mesolimbic system and put forward the potential value of the enzyme as a novel target to treat alcohol use disorders.
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Mattingsdal M, Brown AA, Djurovic S, Sønderby IE, Server A, Melle I, Agartz I, Hovig E, Jensen J, Andreassen OA. Pathway analysis of genetic markers associated with a functional MRI faces paradigm implicates polymorphisms in calcium responsive pathways. Neuroimage 2012; 70:143-9. [PMID: 23274185 DOI: 10.1016/j.neuroimage.2012.12.035] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 11/21/2012] [Accepted: 12/08/2012] [Indexed: 11/17/2022] Open
Abstract
Several lines of evidence suggest that common polygenic variation influences brain function in humans. Combining high-density genetic markers with brain imaging techniques is constricted by the practicalities of collecting sufficiently large brain imaging samples. Pathway analysis promises to leverage knowledge on function of genes to detect recurring signals of moderate effect. We adapt this approach, exploiting the deep information collected on brain function by fMRI methods, to identify molecular pathways containing genetic variants which influence brain activation during a commonly applied experiment based on a face matching task (n=246) which was developed to study neural processing of faces displaying negative emotions. Genetic markers moderately associated (p<10(-4)) with whole brain activation phenotypes constructed by applying principal components to contrast maps, were tested for pathway enrichment using permutation based methods. The most significant pathways are related to post NMDA receptor activation events, driven by genetic variants in calcium/calmodulin-dependent protein kinase II (CAMK2G, CAMK2D) and a calcium-regulated nucleotide exchange factor (RASGRF2) in which all are activated by intracellular calcium/calmodulin. The most significant effect of the combined polygenic model were localized to the left inferior frontal gyrus (p=1.03 × 10(-9)), a region primarily involved in semantic processing but also involved in processing negative emotions. These findings suggest that pathway analysis of GWAS results derived from principal component analysis of fMRI data is a promising method, to our knowledge, not previously described.
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RASGRF2 regulates alcohol-induced reinforcement by influencing mesolimbic dopamine neuron activity and dopamine release. Proc Natl Acad Sci U S A 2012; 109:21128-33. [PMID: 23223532 DOI: 10.1073/pnas.1211844110] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The firing of mesolimbic dopamine neurons is important for drug-induced reinforcement, although underlying genetic factors remain poorly understood. In a recent genome-wide association metaanalysis of alcohol intake, we identified a suggestive association of SNP rs26907 in the ras-specific guanine-nucleotide releasing factor 2 (RASGRF2) gene, encoding a protein that mediates Ca(2+)-dependent activation of the ERK pathway. We performed functional characterization of this gene in relation to alcohol-related phenotypes and mesolimbic dopamine function in both mice and adolescent humans. Ethanol intake and preference were decreased in Rasgrf2(-/-) mice relative to WT controls. Accordingly, ethanol-induced dopamine release in the ventral striatum was blunted in Rasgrf2(-/-) mice. Recording of dopamine neurons in the ventral tegmental area revealed reduced excitability in the absence of Ras-GRF2, likely because of lack of inhibition of the I(A) potassium current by ERK. This deficit provided an explanation for the altered dopamine release, presumably linked to impaired activation of dopamine neurons firing. Functional neuroimaging analysis of a monetary incentive-delay task in 663 adolescent boys revealed significant association of ventral striatal activity during reward anticipation with a RASGRF2 haplotype containing rs26907, the SNP associated with alcohol intake in our previous metaanalysis. This finding suggests a link between the RASGRF2 haplotype and reward sensitivity, a known risk factor for alcohol and drug addiction. Indeed, follow-up of these same boys at age 16 y revealed an association between this haplotype and number of drinking episodes. Together, these combined animal and human data indicate a role for RASGRF2 in the regulation of mesolimbic dopamine neuron activity, reward response, and alcohol use and abuse.
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Majer A, Medina SJ, Niu Y, Abrenica B, Manguiat KJ, Frost KL, Philipson CS, Sorensen DL, Booth SA. Early mechanisms of pathobiology are revealed by transcriptional temporal dynamics in hippocampal CA1 neurons of prion infected mice. PLoS Pathog 2012; 8:e1003002. [PMID: 23144617 PMCID: PMC3493483 DOI: 10.1371/journal.ppat.1003002] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 09/13/2012] [Indexed: 12/23/2022] Open
Abstract
Prion diseases typically have long pre-clinical incubation periods during which time the infectious prion particle and infectivity steadily propagate in the brain. Abnormal neuritic sprouting and synaptic deficits are apparent during pre-clinical disease, however, gross neuronal loss is not detected until the onset of the clinical phase. The molecular events that accompany early neuronal damage and ultimately conclude with neuronal death remain obscure. In this study, we used laser capture microdissection to isolate hippocampal CA1 neurons and determined their pre-clinical transcriptional response during infection. We found that gene expression within these neurons is dynamic and characterized by distinct phases of activity. We found that a major cluster of genes is altered during pre-clinical disease after which expression either returns to basal levels, or alternatively undergoes a direct reversal during clinical disease. Strikingly, we show that this cluster contains a signature highly reminiscent of synaptic N-methyl-D-aspartic acid (NMDA) receptor signaling and the activation of neuroprotective pathways. Additionally, genes involved in neuronal projection and dendrite development were also altered throughout the disease, culminating in a general decline of gene expression for synaptic proteins. Similarly, deregulated miRNAs such as miR-132-3p, miR-124a-3p, miR-16-5p, miR-26a-5p, miR-29a-3p and miR-140-5p follow concomitant patterns of expression. This is the first in depth genomic study describing the pre-clinical response of hippocampal neurons to early prion replication. Our findings suggest that prion replication results in the persistent stimulation of a programmed response that is mediated, at least in part, by synaptic NMDA receptor activity that initially promotes cell survival and neurite remodelling. However, this response is terminated prior to the onset of clinical symptoms in the infected hippocampus, seemingly pointing to a critical juncture in the disease. Manipulation of these early neuroprotective pathways may redress the balance between degeneration and survival, providing a potential inroad for treatment. Neurodegenerative diseases affect an ever-increasing proportion of the population; therefore, there is an urgent need to develop treatments. Prion disorders belong to this group of diseases and although rare and uniquely transmissible, share many features on a sub-cellular level. Central to disease is progressive synaptic impairment that invariably leads to the irreversible loss of neurons. Understanding this process is undoubtedly essential for rational drug discovery. In this study we looked at neurons very early in disease, when prions are barely detectable and there are no clinical symptoms observed. Specifically, we performed a comprehensive analysis of transcriptional changes within a particularly dense area of neurons, the CA1 hippocampus region, from prion-infected and control mice. In this way we were able to enrich our data for molecular changes unique to neurons and minimize those changes characteristic of support cells such as astrocytes and microglia. We detected the activation of a transcriptional program indicative of a protective mechanism within these neurons early in disease. This mechanism diminished as disease progressed and was lost altogether, concurrently with the onset of clinical symptoms. These findings demonstrate the ability of neurons to mount an initial neuroprotective response to prions that could be exploited for therapy development.
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Affiliation(s)
- Anna Majer
- Molecular PathoBiology, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Sarah J. Medina
- Molecular PathoBiology, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Yulian Niu
- Molecular PathoBiology, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Bernard Abrenica
- Molecular PathoBiology, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Kathy J. Manguiat
- Molecular PathoBiology, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Kathy L. Frost
- Molecular PathoBiology, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Clark S. Philipson
- Molecular PathoBiology, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Debra L. Sorensen
- Molecular PathoBiology, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Stephanie A. Booth
- Molecular PathoBiology, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, Manitoba, Canada
- * E-mail:
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Takamaru H, Yamamoto E, Suzuki H, Nojima M, Maruyama R, Yamano HO, Yoshikawa K, Kimura T, Harada T, Ashida M, Suzuki R, Yamamoto H, Kai M, Tokino T, Sugai T, Imai K, Toyota M, Shinomura Y. Aberrant methylation of RASGRF1 is associated with an epigenetic field defect and increased risk of gastric cancer. Cancer Prev Res (Phila) 2012; 5:1203-12. [PMID: 22961779 DOI: 10.1158/1940-6207.capr-12-0056] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Aberrant DNA methylation is implicated in the epigenetic field defect seen in gastric cancer. Our aim in this study was to identify predictive biomarkers by screening for DNA methylation in noncancerous background gastric mucosa from patients with gastric cancer. Using methylated-CpG island amplification coupled with CpG island microarray (MCAM) analysis, we identified 224 genes that were methylated in the noncancerous gastric mucosa of patients with gastric cancer. Among them, RASGRF1 methylation was significantly elevated in gastric mucosa from patients with either intestinal or diffuse type gastric cancer, as compared with mucosa from healthy individuals (8.3% vs. 22.4%, P < 0.001; 8.3% vs. 19.4%, P < 0.001). RASGRF1 methylation was independent of mucosal atrophy and could be used to distinguish both serum pepsinogen test-positive [sensitivity, 70.0%; specificity, 86.7%; area under the receiver operator characteristic (ROC) curve, AUC, 0.763] and -negative patients with gastric cancer (sensitivity, 72.2%; specificity, 87.0%; AUC, 0.844) from healthy individuals. Ectopic expression of RASGRF1 suppressed colony formation and Matrigel invasion by gastric cancer cells, suggesting it may be involved in gastric tumorigenesis. Collectively, our data suggest that RASGRF1 methylation is significantly involved in an epigenetic field defect in the stomach, and that it could be a useful biomarker to identify individuals at high risk for gastric cancer.
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Affiliation(s)
- Hiroyuki Takamaru
- Department of Molecular Biology, Sapporo Medical University, Chuo-Ku, Sapporo, Japan
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Knafo S, Esteban JA. Common pathways for growth and for plasticity. Curr Opin Neurobiol 2012; 22:405-11. [DOI: 10.1016/j.conb.2012.02.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2012] [Revised: 02/13/2012] [Accepted: 02/15/2012] [Indexed: 11/24/2022]
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