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Lopez-Tello J, Kiu R, Schofield Z, Zhang CXW, van Sinderen D, Le Gall G, Hall LJ, Sferruzzi-Perri AN. Maternal gut Bifidobacterium breve modifies fetal brain metabolism in germ-free mice. Mol Metab 2024; 88:102004. [PMID: 39127167 PMCID: PMC11401360 DOI: 10.1016/j.molmet.2024.102004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Revised: 08/06/2024] [Accepted: 08/06/2024] [Indexed: 08/12/2024] Open
Abstract
BACKGROUND Recent advances have significantly expanded our understanding of the gut microbiome's influence on host physiology and metabolism. However, the specific role of certain microorganisms in gestational health and fetal development remains underexplored. OBJECTIVE This study investigates the impact of Bifidobacterium breve UCC2003 on fetal brain metabolism when colonized in the maternal gut during pregnancy. METHODS Germ-free pregnant mice were colonized with or without B. breve UCC2003 during pregnancy. The metabolic profiles of fetal brains were analyzed, focusing on the presence of key metabolites and the expression of critical metabolic and cellular pathways. RESULTS Maternal colonization with B. breve resulted in significant metabolic changes in the fetal brain. Specifically, ten metabolites, including citrate, 3-hydroxyisobutyrate, and carnitine, were reduced in the fetal brain. These alterations were accompanied by increased abundance of transporters involved in glucose and branched-chain amino acid uptake. Furthermore, supplementation with this bacterium was associated with elevated expression of critical metabolic pathways such as PI3K-AKT, AMPK, STAT5, and Wnt-β-catenin signaling, including its receptor Frizzled-7. Additionally, there was stabilization of HIF-2 protein and modifications in genes and proteins related to cellular growth, axogenesis, and mitochondrial function. CONCLUSIONS The presence of maternal B. breve during pregnancy plays a crucial role in modulating fetal brain metabolism and growth. These findings suggest that Bifidobacterium could modify fetal brain development, potentially offering new avenues for enhancing gestational health and fetal development through microbiota-targeted interventions.
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Affiliation(s)
- Jorge Lopez-Tello
- Department of Physiology, Development, and Neuroscience, Centre for Trophoblast Research, University of Cambridge, Cambridge, UK; Department of Physiology, Faculty of Medicine. Autonomous University of Madrid, Spain.
| | - Raymond Kiu
- Food, Microbiome & Health, Quadram Institute Bioscience, Norwich Research Park, Norwich, UK; Institute of Microbiology & Infection, University of Birmingham, Birmingham, UK; Department of Microbes, Infection & Microbiomes, School of Infection, Inflammation & Immunology, University of Birmingham, Birmingham, UK
| | - Zoe Schofield
- Food, Microbiome & Health, Quadram Institute Bioscience, Norwich Research Park, Norwich, UK
| | - Cindy X W Zhang
- Department of Physiology, Development, and Neuroscience, Centre for Trophoblast Research, University of Cambridge, Cambridge, UK
| | | | - Gwénaëlle Le Gall
- Norwich Medical School, University of East Anglia, Bob Champion Research and Education Building, James Watson Road, Norwich Research Park, Norwich NR4 7UQ, UK
| | - Lindsay J Hall
- Food, Microbiome & Health, Quadram Institute Bioscience, Norwich Research Park, Norwich, UK; Institute of Microbiology & Infection, University of Birmingham, Birmingham, UK; Department of Microbes, Infection & Microbiomes, School of Infection, Inflammation & Immunology, University of Birmingham, Birmingham, UK
| | - Amanda N Sferruzzi-Perri
- Department of Physiology, Development, and Neuroscience, Centre for Trophoblast Research, University of Cambridge, Cambridge, UK
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Ma J, Hu Z, Yue H, Luo Y, Wang C, Wu X, Gu Y, Wang L. GRM2 Regulates Functional Integration of Adult-Born DGCs by Paradoxically Modulating MEK/ERK1/2 Pathway. J Neurosci 2023; 43:2822-2836. [PMID: 36878727 PMCID: PMC10124958 DOI: 10.1523/jneurosci.1886-22.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 02/01/2023] [Accepted: 02/19/2023] [Indexed: 03/08/2023] Open
Abstract
Metabotropic glutamate receptor 2 (GRM2) is highly expressed in hippocampal dentate granule cells (DGCs), regulating synaptic transmission and hippocampal functions. Newborn DGCs are continuously generated throughout life and express GRM2 when they are mature. However, it remained unclear whether and how GRM2 regulates the development and integration of these newborn neurons. We discovered that the expression of GRM2 in adult-born DGCs increased with neuronal development in mice of both sexes. Lack of GRM2 caused developmental defects of DGCs and impaired hippocampus-dependent cognitive functions. Intriguingly, our data showed that knockdown of Grm2 resulted in decreased b/c-Raf kinases and paradoxically led to an excessive activation of MEK/ERK1/2 pathway. Inhibition of MEK ameliorated the developmental defects caused by Grm2 knockdown. Together, our results indicate that GRM2 is necessary for the development and functional integration of newborn DGCs in the adult hippocampus through regulating the phosphorylation and activation state of MEK/ERK1/2 pathway.SIGNIFICANCE STATEMENT Metabotropic glutamate receptor 2 (GRM2) is highly expressed in mature dentate granule cells (DGCs) in the hippocampus. It remains unclear whether GRM2 is required for the development and integration of adult-born DGCs. We provided in vivo and in vitro evidence to show that GRM2 regulates the development of adult-born DGCs and their integration into existing hippocampal circuits. Lack of GRM2 in a cohort of newborn DGCs impaired object-to-location memory in mice. Moreover, we revealed that GRM2 knockdown paradoxically upregulated MEK/ERK1/2 pathway by suppressing b/c-Raf in developing neurons, which is likely a common mechanism underlying the regulation of the development of neurons expressing GRM2. Thus, Raf/MEK/ERK1/2 pathway could be a potential target for brain diseases related to GRM2 abnormality.
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Affiliation(s)
- Jiao Ma
- Department of Neurology of the First Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University School of Medicine, 310027 Hangzhou, People's Republic of China
- Center of Stem Cell and Regenerative Medicine, and Department of Neurology of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, 310058 Hangzhou, People's Republic of China
| | - Zhechun Hu
- School of Brain Science and Brain Medicine, Zhejiang University, 310058 Hangzhou, People's Republic of China
| | - Huimin Yue
- Department of Neurology of the First Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University School of Medicine, 310027 Hangzhou, People's Republic of China
- School of Brain Science and Brain Medicine, Zhejiang University, 310058 Hangzhou, People's Republic of China
| | - Yujian Luo
- Department of Neurology of the First Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University School of Medicine, 310027 Hangzhou, People's Republic of China
- School of Brain Science and Brain Medicine, Zhejiang University, 310058 Hangzhou, People's Republic of China
| | - Chao Wang
- School of Brain Science and Brain Medicine, Zhejiang University, 310058 Hangzhou, People's Republic of China
| | - Xuan Wu
- Center of Stem Cell and Regenerative Medicine, and Department of Neurology of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, 310058 Hangzhou, People's Republic of China
| | - Yan Gu
- Center of Stem Cell and Regenerative Medicine, and Department of Neurology of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, 310058 Hangzhou, People's Republic of China
- MOE Frontier Science Center for Brain Science and Brain-Machine Integration, Zhejiang University, 310058 Hangzhou, People's Republic of China
| | - Lang Wang
- Department of Neurology of the First Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University School of Medicine, 310027 Hangzhou, People's Republic of China
- School of Brain Science and Brain Medicine, Zhejiang University, 310058 Hangzhou, People's Republic of China
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3
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Zaręba P, Partyka A, Latacz G, Satała G, Zajdel P, Jaśkowska J. New, Eco-Friendly Method for Synthesis of 3-Chlorophenyl and 1,1'-Biphenyl Piperazinylhexyl Trazodone Analogues with Dual 5-HT 1A/5-HT 7 Affinity and Its Antidepressant-like Activity. Molecules 2022; 27:7270. [PMID: 36364104 PMCID: PMC9658223 DOI: 10.3390/molecules27217270] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/22/2022] [Accepted: 10/24/2022] [Indexed: 07/25/2023] Open
Abstract
Serotonin 5-HT1A and 5-HT7 receptors play an important role in the pathogenesis and pharmacotherapy of depression. Previously identified N-hexyl trazodone derivatives, 2-(6-(4-(3-chlorophenyl)piperazin-1-yl)hexyl)-[1,2,4]triazolo[4,3-a]pyridin-3(2H)-one hydrochloride (7a·HCl), with high affinity for 5-HT1AR and 2-(6-(4-([1,1'-biphenyl]-2-yl)piperazin-1-yl)hexyl)-[1,2,4]triazolo[4,3-a]pyridin-3(2H)-one hydrochloride (7b·HCl), a dual-acting 5-HT1A/5-HT7 receptor ligand, were prepared with a new microwave-assisted method. The protocol for the synthesis of 7a and 7b involved reductive alkylation under a mild reducing agent. We produced the final compounds with yield of 56-63% using ethanol or 51-56% in solvent-free conditions in 4 min. We then determined the 5-HT7R binding mode for compounds 7a and 7b using in silico methods and assessed the preliminary ADME and safety properties (hepatotoxicity and CYP3A4 inhibition) using in vitro methods for 7a·HCl and 7b·HCl. Furthermore, we evaluated antidepressant-like activity of the dual antagonist of 5-HT1A/5-HT7 receptors (7b·HCl) in the forced swim test (FST) in mice. The 5-HT1AR ligand (7a·HCl) with a much lower affinity for 5-HT7R compared to that of 7b·HCl was tested comparatively. Both compounds showed antidepressant activity, while 5-HT1A/5-HT7 double antagonist 7b·HCl showed a stronger and more specific response.
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Affiliation(s)
- Przemysław Zaręba
- Faculty of Chemical Engineering and Technology, Department of Chemical Technology and Environmental Analytics, Cracow University of Technology, 24 Warszawska Street, 31-155 Cracow, Poland
| | - Anna Partyka
- Department of Clinical Pharmacy, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Cracow, Poland
| | - Gniewomir Latacz
- Department of Technology and Biotechnology of Drugs, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Cracow, Poland
| | - Grzegorz Satała
- Department of Medicinal Chemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna Street, 31-343 Kraków, Poland
| | - Paweł Zajdel
- Department of Organic Chemistry, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Cracow, Poland
| | - Jolanta Jaśkowska
- Faculty of Chemical Engineering and Technology, Department of Organic Chemistry and Technology, Cracow University of Technology, 24 Warszawska Street, 31-155 Cracow, Poland
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Aguiar RPD, Newman-Tancredi A, Prickaerts J, Oliveira RMWD. The 5-HT 1A receptor as a serotonergic target for neuroprotection in cerebral ischemia. Prog Neuropsychopharmacol Biol Psychiatry 2021; 109:110210. [PMID: 33333136 DOI: 10.1016/j.pnpbp.2020.110210] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 12/01/2020] [Accepted: 12/10/2020] [Indexed: 12/13/2022]
Abstract
Cerebral ischemia due to stroke or cardiac arrest greatly affects daily functioning and the quality of life of patients and has a high socioeconomic impact due to the surge in their prevalence. Advances in the identification of an effective pharmacotherapy to promote neuroprotection and recovery after a cerebral ischemic insult are, however, limited. The serotonin 1A (5-HT1A) receptor has been implicated in the regulation of several brain functions, including mood, emotions, memory, and neuroplasticity, all of which are deleteriously affected by cerebral ischemia. This review focuses on the specific roles and mechanisms of 5-HT1A receptors in neuroprotection in experimental models of cerebral ischemia. We present experimental evidence that 5-HT1A receptor agonists can prevent neuronal damage and promote functional recovery induced by focal and transient global ischemia in rodents. However, indiscriminate activation of pre-and postsynaptic by non-biased 5-HT1A receptor agonists may be a limiting factor in the anti-ischemic clinical efficacy of these compounds since 5-HT1A receptors in different brain regions can mediate diverging or even contradictory responses. Current insights are presented into the 'biased' 5-HT1A post-synaptic heteroreceptor agonist NLX-101 (also known as F15599), a compound that preferentially and potently stimulates postsynaptic cortical pyramidal neurons without inhibiting firing of serotoninergic neurons, as a potential strategy providing neuroprotection in cerebral ischemic conditions.
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Affiliation(s)
- Rafael Pazinatto de Aguiar
- Department of Pharmacology and Therapeutics, State University of Maringá, Av. Colombo, 5790, CEP 87020-900, Maringá, Paraná, Brazil
| | | | - Jos Prickaerts
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Rúbia Maria Weffort de Oliveira
- Department of Pharmacology and Therapeutics, State University of Maringá, Av. Colombo, 5790, CEP 87020-900, Maringá, Paraná, Brazil.
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Pravoverov K, Whiting K, Thapa S, Bushong T, Trang K, Lein PJ, Chandrasekaran V. MicroRNAs are Necessary for BMP-7-induced Dendritic Growth in Cultured Rat Sympathetic Neurons. Cell Mol Neurobiol 2019; 39:917-934. [PMID: 31104181 PMCID: PMC6713596 DOI: 10.1007/s10571-019-00688-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 05/14/2019] [Indexed: 01/28/2023]
Abstract
Neuronal connectivity is dependent on size and shape of the dendritic arbor. However, mechanisms controlling dendritic arborization, especially in the peripheral nervous system, are not completely understood. Previous studies have shown that bone morphogenetic proteins (BMPs) are important initiators of dendritic growth in peripheral neurons. In this study, we examined the hypothesis that post-transcriptional regulation mediated by microRNAs (miRNAs) is necessary for BMP-7-induced dendritic growth in these neurons. To examine the role of miRNAs in BMP-7-induced dendritic growth, microarray analyses was used to profile miRNA expression in cultured sympathetic neurons from the superior cervical ganglia of embryonic day 21 rat pups at 6 and 24 h after treatment with BMP-7 (50 ng/mL). Our data showed that BMP-7 significantly regulated the expression of 43 of the 762 miRNAs. Of the 43 miRNAs, 22 showed robust gene expression; 14 were upregulated by BMP-7 and 8 were downregulated by BMP-7. The expression profile for miR-335, miR-664-1*, miR-21, and miR-23b was confirmed using qPCR analyses. Functional studies using morphometric analyses of dendritic growth in cultured sympathetic neurons transfected with miRNA mimics and inhibitors indicated that miR-664-1*, miR-23b, and miR-21 regulated early stages of BMP-7-induced dendritic growth. In summary, our data provide evidence for miRNA-mediated post-transcriptional regulation as important downstream component of BMP-7 signaling during early stages of dendritic growth in sympathetic neurons.
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Affiliation(s)
- Kristina Pravoverov
- Department of Biology, Saint Mary’s College of California, 1928 Saint Mary’s Road, Moraga, CA 94556
| | - Katherine Whiting
- Department of Biology, Saint Mary’s College of California, 1928 Saint Mary’s Road, Moraga, CA 94556
| | - Slesha Thapa
- Department of Biology, Saint Mary’s College of California, 1928 Saint Mary’s Road, Moraga, CA 94556
| | - Trevor Bushong
- Department of Biology, Saint Mary’s College of California, 1928 Saint Mary’s Road, Moraga, CA 94556
| | - Karen Trang
- Department of Biology, Saint Mary’s College of California, 1928 Saint Mary’s Road, Moraga, CA 94556
| | - Pamela J. Lein
- Department of Molecular Biosciences, University of California, 1089 Veterinary Medicine Drive, Davis, Davis, CA 95616
| | - Vidya Chandrasekaran
- Department of Biology, Saint Mary’s College of California, 1928 Saint Mary’s Road, Moraga, CA 94556.,Corresponding author: Vidya Chandrasekaran, Department of Biology, Saint Mary’s College of California, Moraga, CA 94556.
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6
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Yi L, Sun H, Zhang H, Chen Y, Zhou L, Xuan L, Zhan T, Jiang Y, Xu S. Down-regulation of HTR1A-modulated ACC activation contributes to stress-induced visceral hyperalgesia in rats. Neurogastroenterol Motil 2019; 31:e13620. [PMID: 31121088 DOI: 10.1111/nmo.13620] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 04/07/2019] [Accepted: 04/24/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND Long-term stress was suggested to cause visceral hypersensitivity and promote functional gastrointestinal disorders (FGIDs). Some brain regions such as the anterior cingulate cortex (ACC) may play an important role for generating visceral hypersensitivity; however, its molecular mechanisms are not clear. This study aimed to explore the role of 5-HT1A receptors (HTR1As) in activating ACC and corresponding mechanism, in stress-induced visceral hyperalgesia rats. METHODS The VH rat model was established by chronic water avoidance stress (WAS), and the visceral sensitivity was measured by electromyogram. Rat's anxiety-like behaviors were evaluated by the open field test (OFT) and elevated plus maze (EPM). To overexpress or down-regulate HTR1A expression, HTR1A-specific lentivirus expressing the green fluorescent protein was administered into the ACC. Protein expression levels were observed by Western blot. RESULTS The protein expression of HTR1A in bilateral ACC in WAS group was significantly lower than that in normal control (NC) and Sham-WAS groups, while the levels of c-fos in the ACC of WAS rats were significantly higher. Down-regulation of HTR1As could induce VH in control rats with the increased expression of c-fos, p-ERK, and p-Akt in ACC, while up-regulation of HTR1As in the ACC could partly inhibit ACC sensitization and stress-induced visceral hyperalgesia. CONCLUSIONS & INFERENCES Down-regulation of HTR1As modulates ACC activation probably through activating ERK and Akt pathways, thus contributes to the formation of stress-induced visceral hyperalgesia.
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Affiliation(s)
- Lisha Yi
- Department of Gastroenterology, Tongji Institute of Digestive Diseases, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Huihui Sun
- Department of Gastroenterology, Tongji Institute of Digestive Diseases, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Haiqin Zhang
- Department of Gastroenterology, Tongji Institute of Digestive Diseases, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Ying Chen
- Department of Gastroenterology, Tongji Institute of Digestive Diseases, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Lu Zhou
- Department of Gastroenterology, Tongji Institute of Digestive Diseases, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Liqian Xuan
- Department of Gastroenterology, Tongji Institute of Digestive Diseases, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Tingting Zhan
- Department of Gastroenterology, Tongji Institute of Digestive Diseases, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yuanxi Jiang
- Department of Gastroenterology, Tongji Institute of Digestive Diseases, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Shuchang Xu
- Department of Gastroenterology, Tongji Institute of Digestive Diseases, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
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7
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Chen J, Niu Q, Xia T, Zhou G, Li P, Zhao Q, Xu C, Dong L, Zhang S, Wang A. ERK1/2-mediated disruption of BDNF-TrkB signaling causes synaptic impairment contributing to fluoride-induced developmental neurotoxicity. Toxicology 2018; 410:222-230. [PMID: 30130557 DOI: 10.1016/j.tox.2018.08.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 08/13/2018] [Accepted: 08/17/2018] [Indexed: 11/26/2022]
Abstract
Excessive exposure to fluoride has adverse effects on neurodevelopment, but the mechanisms remain unclear. This study aimed to investigate the effects of fluoride exposure on synaptogenesis, and focused on the role of brain-derived neurotrophic factor (BDNF)-tyrosine kinase B (TrkB) signaling in these effects. Using Sprague-Dawley rats developmentally exposed to sodium fluoride (NaF) from pregnancy until 6 months of delivery as in vivo model, we showed that fluoride impaired the cognitive abilities of offspring rats, decreased the density of dendritic spines and the expression of synapse proteins synaptophysin (SYN) and postsynaptic density protein-95 (PSD-95) in hippocampus, suggesting fluoride-induced cognitive deficit associates with synaptic impairment. Consistently, NaF treatment reduced dendritic outgrowth and expression of SYN and PSD-95 in human neuroblastoma SH-SY5Y cells. Further studies demonstrated that the BDNF-TrkB axis was disrupted in vivo and in vitro, as manifested by BDNF accumulation and TrkB reduction. Importantly, fluoride treatment increased phospho-extracellular signal-regulated kinases 1 and 2 (p-ERK1/2) expression, while inhibition of p-ERK1/2 significantly attenuated the effects of NaF, indicating a regulating role of p-ERK1/2 in BDNF-TrkB signaling disruption. Collectively, these data suggest that the developmental neurotoxicity of fluoride is associated with the impairment of synaptogenesis, which is caused by ERK1/2-mediated BDNF-TrkB signaling disruption.
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Affiliation(s)
- Jingwen Chen
- Department of Environmental Health, MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030, Hubei, People's Republic of China
| | - Qiang Niu
- Department of Environmental Health, MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030, Hubei, People's Republic of China
| | - Tao Xia
- Department of Environmental Health, MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030, Hubei, People's Republic of China
| | - Guoyu Zhou
- Department of Environmental Health, MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030, Hubei, People's Republic of China
| | - Pei Li
- Department of Environmental Health, MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030, Hubei, People's Republic of China
| | - Qian Zhao
- Department of Environmental Health, MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030, Hubei, People's Republic of China
| | - Chunyan Xu
- Department of Environmental Health, MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030, Hubei, People's Republic of China
| | - Lixin Dong
- Department of Environmental Health, MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030, Hubei, People's Republic of China
| | - Shun Zhang
- Department of Environmental Health, MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030, Hubei, People's Republic of China.
| | - Aiguo Wang
- Department of Environmental Health, MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030, Hubei, People's Republic of China.
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8
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Rojas P, Aguayo F, Neira D, Tejos M, Aliaga E, Muñoz J, Parra C, Fiedler J. Dual effect of serotonin on the dendritic growth of cultured hippocampal neurons: Involvement of 5-HT1A and 5-HT7 receptors. Mol Cell Neurosci 2017; 85:148-161. [DOI: 10.1016/j.mcn.2017.09.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 09/04/2017] [Accepted: 09/29/2017] [Indexed: 01/11/2023] Open
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9
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Rojas PS, Fiedler JL. What Do We Really Know About 5-HT 1A Receptor Signaling in Neuronal Cells? Front Cell Neurosci 2016; 10:272. [PMID: 27932955 PMCID: PMC5121227 DOI: 10.3389/fncel.2016.00272] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Accepted: 11/09/2016] [Indexed: 01/04/2023] Open
Abstract
Serotonin (5-HT) is a neurotransmitter that plays an important role in neuronal plasticity. Variations in the levels of 5-HT at the synaptic cleft, expression or dysfunction of 5-HT receptors may alter brain development and predispose to various mental diseases. Here, we review the transduction pathways described in various cell types transfected with recombinant 5-HT1A receptor (5-HT1AR), specially contrasting with those findings obtained in neuronal cells. The 5-HT1AR is detected in early stages of neural development and is located in the soma, dendrites and spines of hippocampal neurons. The 5-HT1AR differs from other 5-HT receptors because it is coupled to different pathways, depending on the targeted cell. The signaling pathway associated with this receptor is determined by Gα isoforms and some cascades involve βγ signaling. The activity of 5-HT1AR usually promotes a reduction in neuronal excitability and firing, provokes a variation in cAMP and Ca2+, levels which may be linked to specific types of behavior and cognition. Furthermore, evidence indicates that 5-HT1AR induces neuritogesis and synapse formation, probably by modulation of the neuronal cytoskeleton through MAPK and phosphoinositide-3-kinase (PI3K)-Akt signaling pathways. Advances in understanding the actions of 5-HT1AR and its association with different signaling pathways in the central nervous system will reveal their pivotal role in health and disease.
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Affiliation(s)
- Paulina S Rojas
- Laboratory of Neuroplasticity and Neurogenetics, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de ChileSantiago, Chile; Faculty of Medicine, School of Pharmacy, Universidad Andres BelloSantiago, Chile
| | - Jenny L Fiedler
- Laboratory of Neuroplasticity and Neurogenetics, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile Santiago, Chile
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Carrella S, Barbato S, D’Agostino Y, Salierno FG, Manfredi A, Banfi S, Conte I. TGF-β Controls miR-181/ERK Regulatory Network during Retinal Axon Specification and Growth. PLoS One 2015; 10:e0144129. [PMID: 26641497 PMCID: PMC4671616 DOI: 10.1371/journal.pone.0144129] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 11/14/2015] [Indexed: 12/03/2022] Open
Abstract
Retinal axon specification and growth are critically sensitive to the dosage of numerous signaling molecules and transcription factors. Subtle variations in the expression levels of key molecules may result in a variety of axonal growth anomalies. miR-181a and miR-181b are two eye-enriched microRNAs whose inactivation in medaka fish leads to alterations of the proper establishment of connectivity and function in the visual system. miR-181a/b are fundamental regulators of MAPK signaling and their role in retinal axon growth and specification is just beginning to be elucidated. Here we demonstrate that miR-181a/b are key nodes in the interplay between TGF-β and MAPK/ERK within the functional pathways that control retinal axon specification and growth. Using a variety of in vivo and in vitro approaches in medaka fish, we demonstrate that TGF-β signaling controls the miR-181/ERK regulatory network, which in turn strengthens the TGF-β-mediated regulation of RhoA degradation. Significantly, these data uncover the role of TGF-β signaling in vivo, for the first time, in defining the correct wiring and assembly of functional retina neural circuits and further highlight miR-181a/b as key factors in axon specification and growth.
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Affiliation(s)
- Sabrina Carrella
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, Pozzuoli (Naples), 80078, Italy
| | - Sara Barbato
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, Pozzuoli (Naples), 80078, Italy
| | - Ylenia D’Agostino
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, Pozzuoli (Naples), 80078, Italy
| | | | - Anna Manfredi
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, Pozzuoli (Naples), 80078, Italy
| | - Sandro Banfi
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, Pozzuoli (Naples), 80078, Italy
- Medical Genetics, Dipartimento di Biochimica, Biofisica e Patologia Generale, Second University of Naples, via Luigi De Crecchio 7, 80138, Naples, Italy
- * E-mail: (SB); (IC)
| | - Ivan Conte
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, Pozzuoli (Naples), 80078, Italy
- * E-mail: (SB); (IC)
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11
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Carrella S, D'Agostino Y, Barbato S, Huber-Reggi SP, Salierno FG, Manfredi A, Neuhauss SCF, Banfi S, Conte I. miR-181a/b control the assembly of visual circuitry by regulating retinal axon specification and growth. Dev Neurobiol 2015; 75:1252-67. [PMID: 25728313 PMCID: PMC5033011 DOI: 10.1002/dneu.22282] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 02/23/2015] [Accepted: 02/24/2015] [Indexed: 01/31/2023]
Abstract
Connectivity and function of neuronal circuitry require the correct specification and growth of axons and dendrites. Here, we identify the microRNAs miR‐181a and miR‐181b as key regulators of retinal axon specification and growth. Loss of miR‐181a/b in medaka fish (Oryzias latipes) failed to consolidate amacrine cell processes into axons and delayed the growth of retinal ganglion cell (RGC) axons. These alterations were accompanied by defects in visual connectivity and function. We demonstrated that miR‐181a/b exert these actions through negative modulation of MAPK/ERK signaling that in turn leads to RhoA reduction and proper neuritogenesis in both amacrine cells and RGCs via local cytoskeletal rearrangement. Our results identify a new pathway for axon specification and growth unraveling a crucial role of miR‐181a/b in the proper establishment of visual system connectivity and function. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 75: 1252–1267, 2015
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Affiliation(s)
- Sabrina Carrella
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, Pozzuoli (Naples), 80078, Italy
| | - Ylenia D'Agostino
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, Pozzuoli (Naples), 80078, Italy
| | - Sara Barbato
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, Pozzuoli (Naples), 80078, Italy
| | - Sabina P Huber-Reggi
- Institute of Molecular Life Sciences, Division of Neurobiology, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Francesco G Salierno
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, Pozzuoli (Naples), 80078, Italy
| | - Anna Manfredi
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, Pozzuoli (Naples), 80078, Italy
| | - Stephan C F Neuhauss
- Institute of Molecular Life Sciences, Division of Neurobiology, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Sandro Banfi
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, Pozzuoli (Naples), 80078, Italy.,Medical Genetics, Department of Biochemistry, Biophysics and General Pathology, Second University of Naples, via Luigi De Crecchio 7, 80138, Naples, Italy
| | - Ivan Conte
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, Pozzuoli (Naples), 80078, Italy
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12
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Zhang L, Bartley CM, Gong X, Hsieh LS, Lin TV, Feliciano DM, Bordey A. MEK-ERK1/2-dependent FLNA overexpression promotes abnormal dendritic patterning in tuberous sclerosis independent of mTOR. Neuron 2015; 84:78-91. [PMID: 25277454 DOI: 10.1016/j.neuron.2014.09.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2014] [Indexed: 12/17/2022]
Abstract
Abnormal dendritic complexity is a shared feature of many neurodevelopmental disorders associated with neurological defects. Here, we found that the actin-crosslinking protein filamin A (FLNA) is overexpressed in tuberous sclerosis complex (TSC) mice, a PI3K-mTOR model of neurodevelopmental disease that is associated with abnormal dendritic complexity. Both under- and overexpression of FLNA in wild-type neurons led to more complex dendritic arbors in vivo, suggesting that an optimal level of FLNA expression is required for normal dendritogenesis. In Tsc1(null) neurons, knocking down FLNA in vivo prevented dendritic abnormalities. Surprisingly, FLNA overexpression in Tsc1(null) neurons was dependent on MEK1/2 but not mTOR activity, despite both pathways being hyperactive. In addition, increasing MEK-ERK1/2 activity led to dendritic abnormalities via FLNA, and decreasing MEK-ERK1/2 signaling in Tsc1(null) neurons rescued dendritic defects. These data demonstrate that altered FLNA expression increases dendritic complexity and contributes to pathologic dendritic patterning in TSC in an mTOR-independent, ERK1/2-dependent manner.
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Affiliation(s)
- Longbo Zhang
- Department of Neurosurgery, Xiangya Hospital, Central South University, 85 Xiangya Street, Changsha, 410008, China; Department of Neurosurgery and Department of Cellular & Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8082, USA
| | - Christopher M Bartley
- Department of Neurosurgery and Department of Cellular & Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8082, USA; Department of Neurobiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Xuan Gong
- Department of Neurosurgery, Xiangya Hospital, Central South University, 85 Xiangya Street, Changsha, 410008, China; Department of Neurosurgery and Department of Cellular & Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8082, USA
| | - Lawrence S Hsieh
- Department of Neurosurgery and Department of Cellular & Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8082, USA
| | - Tiffany V Lin
- Department of Neurosurgery and Department of Cellular & Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8082, USA
| | - David M Feliciano
- Department of Neurosurgery and Department of Cellular & Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8082, USA
| | - Angélique Bordey
- Department of Neurosurgery and Department of Cellular & Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8082, USA.
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13
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Dendrite complexity of sympathetic neurons is controlled during postnatal development by BMP signaling. J Neurosci 2013; 33:15132-44. [PMID: 24048844 DOI: 10.1523/jneurosci.4748-12.2013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Dendrite development is controlled by the interplay of intrinsic and extrinsic signals affecting initiation, growth, and maintenance of complex dendrites. Bone morphogenetic proteins (BMPs) stimulate dendrite growth in cultures of sympathetic, cortical, and hippocampal neurons but it was unclear whether BMPs control dendrite morphology in vivo. Using a conditional knock-out strategy to eliminate Bmpr1a and Smad4 in immature noradrenergic sympathetic neurons we now show that dendrite length, complexity, and neuron cell body size are reduced in adult mice deficient of Bmpr1a. The combined deletion of Bmpr1a and Bmpr1b causes no further decrease in dendritic features. Sympathetic neurons devoid of Bmpr1a/1b display normal Smad1/5/8 phosphorylation, which suggests that Smad-independent signaling paths are involved in dendritic growth control downstream of BMPR1A/B. Indeed, in the Smad4 conditional knock-out dendrite and cell body size are not affected and dendrite complexity and number are increased. Together, these results demonstrate an in vivo function for BMPs in the generation of mature sympathetic neuron dendrites. BMPR1 signaling controls dendrite complexity postnatally during the major dendritic growth period of sympathetic neurons.
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14
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Shi GX, Cai W, Andres DA. Rit subfamily small GTPases: regulators in neuronal differentiation and survival. Cell Signal 2013; 25:2060-8. [PMID: 23770287 DOI: 10.1016/j.cellsig.2013.06.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 06/04/2013] [Indexed: 02/07/2023]
Abstract
Ras family small GTPases serve as binary molecular switches to regulate a broad array of cellular signaling cascades, playing essential roles in a vast range of normal physiological processes, with dysregulation of numerous Ras-superfamily G-protein-dependent regulatory cascades underlying the development of human disease. However, the physiological function for many "orphan" Ras-related GTPases remain poorly characterized, including members of the Rit subfamily GTPases. Rit is the founding member of a novel branch of the Ras subfamily, sharing close homology with the neuronally expressed Rin and Drosophila Ric GTPases. Here, we highlight recent studies using transgenic and knockout animal models which have begun to elucidate the physiological roles for the Rit subfamily, including emerging roles in the regulation of neuronal morphology and cellular survival signaling, and discuss new genetic data implicating Rit and Rin signaling in disorders such as cancer, Parkinson's disease, autism, and schizophrenia.
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Affiliation(s)
- Geng-Xian Shi
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, BBSRB, 741S. Limestone St., Lexington, KY 40536-0509, USA
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15
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Ishiguro S, Akasaka Y, Kiguchi H, Suzuki T, Imaizumi R, Ishikawa Y, Ito K, Ishii T. Basic fibroblast growth factor induces down-regulation of alpha-smooth muscle actin and reduction of myofibroblast areas in open skin wounds. Wound Repair Regen 2009; 17:617-25. [PMID: 19614927 DOI: 10.1111/j.1524-475x.2009.00511.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
To examine the effects of basic fibroblast growth factor (bFGF) on the inhibition of alpha-smooth muscle actin (alpha-SMA) expression in dermal fibroblasts, we have established two dermal myofibroblastic cell lines positive for alpha-SMA (rat myofibroblasts [RMF] and rat myofibroblast-like [RMFL] cells) and one fibroblastic cell line negative for alpha-SMA (rat fibroblasts cells) as a model of fibroblast differentiation. In contrast to the increased expression of alpha-SMA in RMF and RMFL cells, irrespective of transforming growth factor-beta1 treatment, bFGF induced a decrease in alpha-SMA expression in the myofibroblastic cells and the reduced expression patterns of alpha-SMA differed between cells, as demonstrated by Western blot and reverse transcription polymerase chain reaction analyses. Along with the inhibition of alpha-SMA expression by bFGF, the RMF and RMFL cells also showed different activated expression of extracellular signal-regulated kinase 1/2, suggesting the involvement of extracellular signal-regulated kinase 1/2 activation in the down-regulation of alpha-SMA expression in myofibroblasts. Furthermore, an in vivo study demonstrated that bFGF administration markedly decreases the area that is positive for alpha-SMA expression in the treated wounds after day 18. In contrast, bFGF administration significantly increased the number of terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) staining and alpha-SMA-positive cells at days 10 and 14, and reduced the double-positive cells rapidly after day 18. Collectively, the current investigation identified bFGF as a potent stimulator for the reduction of the myofibroblastic area in vivo, presumably because of its effects on the down-regulation of alpha-SMA expression as well as rapid induction of apoptosis in myofibroblasts.
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Affiliation(s)
- Shigeki Ishiguro
- Department of Pathology, School of Medicine, Toho University, Ohta-City, Tokyo 143-8540, Japan
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Cesarini L, Alfieri P, Pantaleoni F, Vasta I, Cerutti M, Petrangeli V, Mariotti P, Leoni C, Ricci D, Vicari S, Selicorni A, Tartaglia M, Mercuri E, Zampino G. Cognitive profile of disorders associated with dysregulation of the RAS/MAPK signaling cascade. Am J Med Genet A 2009; 149A:140-6. [PMID: 19133693 DOI: 10.1002/ajmg.a.32488] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Mutations in genes coding for transducers participating in the RAS/MAPK pathway have been identified as the molecular cause underlying a group of clinically related developmental disorders with cognitive deficits of variable severity. To determine the spectrum of cognitive defects associated with dysregulation of this signal cascade, we studied the profile of cognitive abilities in patients with mutations affecting the PTPN11, SOS1, HRAS, KRAS, BRAF, RAF1, and MEK1 genes and phenotype-genotype correlations. Our findings support the observation that heterogeneity in cognitive abilities can be at least partially ascribed to the individual affected genes and type of mutation involved. While mutations affecting transducers upstream of RAS were less frequently associated with mental retardation, mutations in downstream components of the pathway were generally associated with a more severe cognitive impairment. Among patients with a heterozygous PTPN11 mutation, the T468M substitution was associated with a mean IQ significantly higher compared to that of individuals carrying the N308D change. Our study provides insights on the range of cognitive abilities in patients with gene mutations causing dysregulation of RAS signaling suggesting that the presence and severity of cognitive involvement can be predicted in part by the gene involved.
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Affiliation(s)
- Laura Cesarini
- Pediatric Neurology Unit, Catholic University, Rome, Italy
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17
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Chaverneff F, Barrett J. Casein kinase II contributes to the synergistic effects of BMP7 and BDNF on Smad 1/5/8 phosphorylation in septal neurons under hypoglycemic stress. J Neurochem 2009; 109:733-43. [PMID: 19222702 DOI: 10.1111/j.1471-4159.2009.05990.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The combination of bone morphogenetic protein 7 (BMP7) and neurotrophins (e.g. brain-derived neurotrophic factor, BDNF) protects septal neurons during hypoglycemic stress. We investigated the signaling mechanisms underlying this synergistic protection. BMP7 (5 nM) increased phosphorylation and nuclear translocation of BMP-responsive Smads 1/5/8 within 30 min in cultures of rat embryonic septal neurons. BDNF (100 ng/mL) enhanced the BMP7-induced increase in phospho-Smad levels in both nucleus and cytoplasm; this effect was more pronounced after a hypoglycemic stress. BDNF increased both Akt and Erk phosphorylation, but pharmacological blockade of these kinase pathways (with wortmannin and U0126, respectively) did not reduce the Smad phosphorylation produced by the BMP7 + BDNF combination. Inhibitors of casein kinase II (CK2) activity reduced the (BMP7 + BDNF)-induced Smad phosphorylation, and this trophic factor combination increased CK2 activity in hypoglycemic cultures. These findings suggest that BDNF can increase BMP-dependent Smad phosphorylation via a mechanism requiring CK2.
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Affiliation(s)
- Florence Chaverneff
- Neuroscience Program, University of Miami Miller School of Medicine, Miami, Florida 33136, USA
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18
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Andres DA, Shi GX, Bruun D, Barnhart C, Lein PJ. Rit signaling contributes to interferon-gamma-induced dendritic retraction via p38 mitogen-activated protein kinase activation. J Neurochem 2008; 107:1436-47. [PMID: 18957053 DOI: 10.1111/j.1471-4159.2008.05708.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The proinflammatory cytokine interferon-gamma (IFNgamma) alters neuronal connectivity via selective regressive effects on dendrites but the signaling pathways that mediate this effect are poorly understood. We recently demonstrated that signaling by Rit, a member of the Ras family of GTPases, modulates dendritic growth in primary cultures of sympathetic and hippocampal neurons. In this study, we investigated a role for Rit signaling in IFNgamma-induced dendritic retraction. Expression of a dominant negative Rit mutant inhibited IFNgamma-induced dendritic retraction in cultured embryonic rat sympathetic and hippocampal neurons. In pheochromacytoma cells and hippocampal neurons, IFNgamma caused rapid Rit activation as indicated by increased GTP binding to Rit. Silencing of Rit by RNA interference suppressed IFNgamma-elicited activation of p38 MAPK in pheochromacytoma cells, and pharmacological inhibition of p38 MAPK significantly attenuated the dendrite-inhibiting effects of IFNgamma in cultured sympathetic and hippocampal neurons without altering signal transducer and activator of transcription 1 activation. These observations identify Rit as a downstream target of IFNgamma and suggest that a novel IFNgamma-Rit-p38 signaling pathway contributes to dendritic retraction and may, therefore, represent a potential therapeutic target in diseases with a significant neuroinflammatory component.
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Affiliation(s)
- Douglas A Andres
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, Kentucky, USA
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19
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Ozog MA, Modha G, Church J, Reilly R, Naus CC. Co-administration of Ciliary Neurotrophic Factor with Its Soluble Receptor Protects against Neuronal Death and Enhances Neurite Outgrowth. J Biol Chem 2008; 283:6546-60. [DOI: 10.1074/jbc.m709065200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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20
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Blunted amygdalar anti-inflammatory cytokine effector response to postnatal stress in prenatally stressed rats. Brain Res 2008; 1196:1-12. [DOI: 10.1016/j.brainres.2007.11.073] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2007] [Revised: 11/20/2007] [Accepted: 11/26/2007] [Indexed: 11/20/2022]
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21
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Luo JM, Cen LP, Zhang XM, Chiang SWY, Huang Y, Lin D, Fan YM, van Rooijen N, Lam DSC, Pang CP, Cui Q. PI3K/akt, JAK/STAT and MEK/ERK pathway inhibition protects retinal ganglion cells via different mechanisms after optic nerve injury. Eur J Neurosci 2007; 26:828-42. [PMID: 17714182 DOI: 10.1111/j.1460-9568.2007.05718.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Recently we unexpectedly found that PI3K/akt, JAK/STAT and MEK/ERK pathway inhibitors enhanced retinal ganglion cell (RGC) survival after optic nerve (ON) axotomy in adult rat, a phenomenon contradictory to conventional belief that these pathways are pro-survival. In this study we showed that: (i) the RGC protection was pathway inhibition-dependent; (ii) inhibition of PI3K/akt and JAK/STAT, but not MEK/ERK, activated macrophages in the eye, (iii) macrophage removal from the eye using clodronate liposomes significantly impeded PI3K/akt and JAK/STAT inhibition-induced RGC survival and axon regeneration whereas it only slightly affected MEK/ERK inhibition-dependent protection; (iv) in the absence of recruited macrophages in the eye, inhibition of PI3K/akt or JAK/STAT did not influence RGC survival; and (v) strong PI3K/akt, JAK/STAT and MEK/ERK pathway activities were located in RGCs but not macrophages after ON injury. In retinal explants, in which supply of blood-derived macrophages is absent, MEK/ERK inhibition promoted RGC survival whereas PI3K/akt or JAK/STAT inhibition had no effect on RGC viability. However, MEK/ERK inhibition exerted opposite effects on the viability of purified adult RGCs at different concentrations in vitro, suggesting that this pathway may be bifunctional depending on the level of pathway activity. Our data thus demonstrate that inhibition of the PI3K/akt or JAK/STAT pathway activated macrophages to facilitate RGC protection after ON injury whereas the two pathways per se did not modulate RGC viability under the injury conditions (in the absence of the pathway activators). In contrast, the MEK/ERK pathway inhibition protected RGCs via macrophage-independent mechanism(s).
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Affiliation(s)
- Jian-Min Luo
- Joint Shantou International Eye Center of Shantou University, Shantou, China
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22
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Macrae VE, Ahmed SF, Mushtaq T, Farquharson C. IGF-I signalling in bone growth: inhibitory actions of dexamethasone and IL-1beta. Growth Horm IGF Res 2007; 17:435-439. [PMID: 17590365 DOI: 10.1016/j.ghir.2007.05.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Revised: 05/09/2007] [Accepted: 05/11/2007] [Indexed: 01/22/2023]
Abstract
OBJECTIVE To determine if glucocorticoids and proinflammatory cytokines inhibit bone growth through a common mechanism involving impaired IGF-I signalling. DESIGN IGF-I (100 ng/ml), dexamethasone (dex) (10(-6)M) and IL-1beta (10 ng/ml) with inhibitors of the PI3K (LY294002) and Erk 1/2 (PD98059 and UO126) IGF-I pathways (all 10 microM) were studied using the ATDC5 chondrocyte cell line and murine fetal metatarsal cultures. RESULTS IGF-I stimulated ATDC5 chondrocyte proliferation (322%; P < 0.001 versus control). Addition of PD or LY individually to IGF-I supplemented ATDC5 cultures partially reduced proliferation by 32% (P < 0.001), and 66% (P < 0.001), respectively. PD and LY in combination blocked all IGF-I stimulated ATDC5 proliferation. LY significantly reversed IGF-I stimulatory effects on metatarsal growth (P < 0.001), whereas PD and UO treatment had no effect. IGF-I induced ATDC5 proliferation was further decreased when Dex (24%; P < 0.01) or IL-1beta (33%; P < 0.001) were added to PD but not LY cultures. Metatarsal growth inhibition by LY was unaltered by Dex or IL-1beta addition. CONCLUSIONS Both the PI3K and Erk 1/2 pathways contributed independently to IGF-I mediated ATDC5 proliferation. However in metatarsal cultures, the Erk 1/2 pathway was not required for IGF-I stimulated growth. Dex and IL-1beta may primarily inhibit IGF-I induced bone growth through the PI3K pathway.
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Affiliation(s)
- Vicky E Macrae
- Bone Biology Group, Division of Gene Function and Development, Roslin Institute, Roslin, Midlothian, Edinburgh EH25 9PS, United Kingdom.
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23
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Lein PJ, Guo X, Shi GX, Moholt-Siebert M, Bruun D, Andres DA. The novel GTPase Rit differentially regulates axonal and dendritic growth. J Neurosci 2007; 27:4725-36. [PMID: 17460085 PMCID: PMC3495986 DOI: 10.1523/jneurosci.5633-06.2007] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The Rit GTPase is widely expressed in developing and adult nervous systems, and our previous data with pheochromocytoma cells implicate Rit signaling in NGF-induced neurite outgrowth. In this study, we investigated a role for Rit in neuronal morphogenesis. Expression of a dominant-negative (dn) Rit mutant in hippocampal neurons inhibited axonal growth but potentiated dendritic growth. Conversely, a constitutively active (ca) Rit mutant promoted axonal growth but inhibited dendritic growth. Dendritogenesis is regulated differently in sympathetic neurons versus hippocampal neurons in that sympathetic neurons require NGF and bone morphogenetic proteins (BMPs) to trigger dendritic growth. Despite these differences, dnRit potentiated and caRit blocked BMP7-induced dendritic growth in sympathetic neurons. Biochemical studies indicated that BMP7 treatments that caused dendritic growth also decreased Rit GTP loading. Additional studies demonstrate that caRit increased extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation and pharmacological inhibition of MEK1 (mitogen-activated protein kinase/ERK 1) blocked the axon-promoting and dendrite-inhibiting effects of caRit. These observations suggest that Rit is a convergence point for multiple signaling pathways and it functions to promote axonal growth but inhibit dendritic growth via activation of ERK1/2. Modulation of the activational status of Rit may therefore represent a generalized mechanism across divergent neuronal cell types for regulating axonal versus dendritic growth modes.
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Affiliation(s)
- Pamela J Lein
- Center for Research on Occupational and Environmental Toxicology, Oregon Health & Science University, Portland, Oregon 97239, USA.
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Hadley D, Murphy T, Valladares O, Hannenhalli S, Ungar L, Kim J, Bućan M. Patterns of sequence conservation in presynaptic neural genes. Genome Biol 2007; 7:R105. [PMID: 17096848 PMCID: PMC1794582 DOI: 10.1186/gb-2006-7-11-r105] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2006] [Revised: 09/25/2006] [Accepted: 11/10/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The neuronal synapse is a fundamental functional unit in the central nervous system of animals. Because synaptic function is evolutionarily conserved, we reasoned that functional sequences of genes and related genomic elements known to play important roles in neurotransmitter release would also be conserved. RESULTS Evolutionary rate analysis revealed that presynaptic proteins evolve slowly, although some members of large gene families exhibit accelerated evolutionary rates relative to other family members. Comparative sequence analysis of 46 megabases spanning 150 presynaptic genes identified more than 26,000 elements that are highly conserved in eight vertebrate species, as well as a small subset of sequences (6%) that are shared among unrelated presynaptic genes. Analysis of large gene families revealed that upstream and intronic regions of closely related family members are extremely divergent. We also identified 504 exceptionally long conserved elements (> or =360 base pairs, > or =80% pair-wise identity between human and other mammals) in intergenic and intronic regions of presynaptic genes. Many of these elements form a highly stable stem-loop RNA structure and consequently are candidates for novel regulatory elements, whereas some conserved noncoding elements are shown to correlate with specific gene expression profiles. The SynapseDB online database integrates these findings and other functional genomic resources for synaptic genes. CONCLUSION Highly conserved elements in nonprotein coding regions of 150 presynaptic genes represent sequences that may be involved in the transcriptional or post-transcriptional regulation of these genes. Furthermore, comparative sequence analysis will facilitate selection of genes and noncoding sequences for future functional studies and analysis of variation studies in neurodevelopmental and psychiatric disorders.
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Affiliation(s)
- Dexter Hadley
- Penn Center for Bioinformatics, 423 Guardian Drive, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Genomics and Computational Biology Graduate Group, 423 Guardian Drive, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Tara Murphy
- Department of Genetics in the School of Medicine, University of Pennsylvania, 415 Curie Boulevard Philadelphia, Pennsylvania 19104, USA
- UCLA Neuroscience Graduate Office, 695 Young Drive South, Los Angeles, California 90095, USA
| | - Otto Valladares
- Department of Genetics in the School of Medicine, University of Pennsylvania, 415 Curie Boulevard Philadelphia, Pennsylvania 19104, USA
| | - Sridhar Hannenhalli
- Penn Center for Bioinformatics, 423 Guardian Drive, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Genomics and Computational Biology Graduate Group, 423 Guardian Drive, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Lyle Ungar
- Penn Center for Bioinformatics, 423 Guardian Drive, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Department of Computer & Information Sciences in School of Engineering and Applied Sciences, 3330 Walnut Street, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Junhyong Kim
- Penn Center for Bioinformatics, 423 Guardian Drive, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Department of Computer & Information Sciences in School of Engineering and Applied Sciences, 3330 Walnut Street, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Department of Biology in the School of Arts and Sciences, 433 S University Avenue, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Maja Bućan
- Penn Center for Bioinformatics, 423 Guardian Drive, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Department of Genetics in the School of Medicine, University of Pennsylvania, 415 Curie Boulevard Philadelphia, Pennsylvania 19104, USA
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25
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Hampton DW, Steeves JD, Fawcett JW, Ramer MS. Spinally upregulated noggin suppresses axonal and dendritic plasticity following dorsal rhizotomy. Exp Neurol 2007; 204:366-79. [PMID: 17258709 DOI: 10.1016/j.expneurol.2006.11.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2006] [Revised: 11/06/2006] [Accepted: 11/29/2006] [Indexed: 01/20/2023]
Abstract
Bone morphogenetic proteins (BMPs) and their antagonists, including noggin, are required for nervous system development, but their potential roles in the reactions of the adult central nervous system to injury are unknown. Here we have examined the expression of noggin and BMPs in the spinal cord following dorsal rhizotomy. Through the use of a function-blocking antibody, we have also investigated the role of endogenous noggin in the neuritic plasticity which follows rhizotomy. Dorsal rhizotomy resulted in the upregulation of BMPs 2/4, 7 and noggin in the superficial white matter and in the dorsal neuropil of the spinal cord. These co-localized with glial fibrillary acidic protein, indicating their expression by astrocytes. Because BMPs induce dendritic sprouting and synaptogenesis in some neuronal populations in vitro, we hypothesized that administration of a noggin function-blocking antibody (FbAb) in vivo would augment rhizotomy-induced sprouting in the spinal cord. Topical application of noggin-FbAb to the dorsal surface of the spinal cord following rhizotomy resulted in significant increases in the density of microtubule-associated protein 2 (MAP-2) and substance P (SP)-positive processes within the lateral spinal nucleus. In the deafferented dorsal horn, noggin-FbAb treatment induced significant increases in the density of SP, calcitonin gene-related peptide (CGRP)- and 5-hydroxytryptamine (5-HT)-positive axons. These results suggest a novel mechanism by which endogenous plasticity of spared axons is suppressed following dorsal rhizotomy, and which might be exploited to improve the outcome of spinal cord injury and other CNS trauma.
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Affiliation(s)
- David W Hampton
- ICORD, University of British Columbia, 6270 University Blvd., Vancouver, BC, Canada V6T 1Z4
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26
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Yang LY, Ko WC, Lin CM, Lin JW, Wu JC, Lin CJ, Cheng HH, Shih CM. Antioxidant N-acetylcysteine blocks nerve growth factor-induced H2O2/ERK signaling in PC12 cells. Ann N Y Acad Sci 2006; 1042:325-37. [PMID: 15965078 DOI: 10.1196/annals.1338.056] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We investigated whether H2O2, superoxide, and ERK participate in nerve growth factor (NGF)-induced signaling cascades and whether antioxidant N-acetylcysteine (NAC) regulates these NGF-induced responses. PC12 cells were cultured in medium containing NGF or vehicle with or without NAC pretreatment, and the intracellular H2O2 and superoxide levels and the amount of phosphorylated ERK were evaluated by flow cytometry and Western blotting, respectively. We found that NGF increased intracellular H2O2 concentration and activated ERK but failed to affect intracellular superoxide level. Moreover, NAC counteracted these NGF-induced responses. These findings demonstrate that NAC blocks the NGF-induced H2O2/ERK signaling in PC12 cells.
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Affiliation(s)
- Liang-Yo Yang
- Department of Physiology, Taipei Medical University, Taipei 110, Taiwan
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27
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Zamburlin P, Gilardino A, Dalmazzo S, Ariano P, Lovisolo D. Temporal dynamics of neurite outgrowth promoted by basic fibroblast growth factor in chick ciliary ganglia. J Neurosci Res 2006; 84:505-14. [PMID: 16786578 DOI: 10.1002/jnr.20954] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Basic fibroblast growth factor (bFGF) is a potent and multifunctional neurotrophic factor that can influence neuronal survival and differentiation. It has been shown to modulate growth and orientation of neuritic processes both in intact organs and in neuronal cultures, with a wide spectrum of effects on different preparations. Here we report that it promotes neurite growth in developing parasympathetic neurons from the chick ciliary ganglion. We have used both organotypic cultures and dissociated neurons, and we have combined assessment of global neurite growth by immunocytochemical techniques with evaluation of dynamic parameters of single neurites via time-lapse microscopy. We show that laminin, a molecule of the extracellular matrix that has been associated with stimulation of neurite extension, has only a limited and short-lived effect on neurite outgrowth. In contrast, bFGF can promote global growth of the neuritic network both in whole ganglia and in dissociated cultures for times up to 48 hr, and this effect is related to an increase in the growth rate of single neurites. Moreover, the effect can be observed even in enriched neuronal cultures, pointing to a direct action of bFGF on neurons.
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28
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Yuen EY, Jiang Q, Chen P, Gu Z, Feng J, Yan Z. Serotonin 5-HT1A receptors regulate NMDA receptor channels through a microtubule-dependent mechanism. J Neurosci 2006; 25:5488-501. [PMID: 15944377 PMCID: PMC6724987 DOI: 10.1523/jneurosci.1187-05.2005] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The serotonin system and NMDA receptors (NMDARs) in prefrontal cortex (PFC) are both critically involved in the regulation of cognition and emotion under normal and pathological conditions; however, the interactions between them are essentially unknown. Here we show that serotonin, by activating 5-HT(1A) receptors, inhibited NMDA receptor-mediated ionic and synaptic currents in PFC pyramidal neurons, and the NR2B subunit-containing NMDA receptor is the primary target of 5-HT(1A) receptors. This effect of 5-HT(1A) receptors was blocked by agents that interfere with microtubule assembly, as well as by cellular knock-down of the kinesin motor protein KIF17 (kinesin superfamily member 17), which transports NR2B-containing vesicles along microtubule in neuronal dendrites. Inhibition of either CaMKII (calcium/calmodulin-dependent kinase II) or MEK/ERK (mitogen-activated protein kinase kinase/extracellular signal-regulated kinase) abolished the 5-HT(1A) modulation of NMDAR currents. Biochemical evidence also indicates that 5-HT(1A) activation reduced microtubule stability, which was abolished by CaMKII or MEK inhibitors. Moreover, immunocytochemical studies show that 5-HT(1A) activation decreased the number of surface NR2B subunits on dendrites, which was prevented by the microtubule stabilizer. Together, these results suggest that serotonin suppresses NMDAR function through a mechanism dependent on microtubule/kinesin-based dendritic transport of NMDA receptors that is regulated by CaMKII and ERK signaling pathways. The 5-HT(1A)-NMDAR interaction provides a potential mechanism underlying the role of serotonin in controlling emotional and cognitive processes subserved by PFC.
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Affiliation(s)
- Eunice Y Yuen
- Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York 14214, USA
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29
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Senaratne W, Andruzzi L, Ober CK. Self-assembled monolayers and polymer brushes in biotechnology: current applications and future perspectives. Biomacromolecules 2005; 6:2427-48. [PMID: 16153077 DOI: 10.1021/bm050180a] [Citation(s) in RCA: 486] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The chemistry and topography of a surface affect biological response and are of fundamental importance, especially when living systems encounter synthetic surfaces. Most biomolecules have immense recognition power (specific binding) and simultaneously have a tendency to physically adsorb onto a solid substrate without specific receptor recognition (nonspecific adsorption). Therefore, to create useful materials for many biotechnology applications, interfaces are required that have both enhanced specific binding and reduced nonspecific binding. Thus, in applications such as sensors, the tailoring of surface chemistry and the use of micro or nanofabrication techniques becomes an important avenue for the production of surfaces with specific binding properties and minimal background interference. Both self-assembled monolayers (SAMs) and polymer brushes have attracted considerable attention as surface-active materials. In this review, we discuss both of these materials with their potential applications in biotechnology. We also summarize lithographic methods for pattern formation using combined top-down and bottom-up approaches and briefly discuss the future of these materials by describing emerging new applications.
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Affiliation(s)
- Wageesha Senaratne
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
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Abstract
The precise coordination of the many events in nervous system development is absolutely critical for the correct establishment of functional circuits. The postganglionic sympathetic neuron has been an amenable model for studying peripheral nervous system formation. Factors that control several developmental events, including multiple stages of axon extension, neuron survival and death, dendritogenesis, synaptogenesis, and establishment of functional diversity, have been identified in this neuron type. This knowledge allows us to integrate the various intricate processes involved in the formation of a functional sympathetic nervous system and thereby create a paradigm for understanding neuronal development in general.
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Affiliation(s)
- Natalia O Glebova
- Department of Neuroscience, Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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Webber CA, Chen YY, Hehr CL, Johnston J, McFarlane S. Multiple signaling pathways regulate FGF-2-induced retinal ganglion cell neurite extension and growth cone guidance. Mol Cell Neurosci 2005; 30:37-47. [PMID: 15996482 DOI: 10.1016/j.mcn.2005.05.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2004] [Revised: 04/23/2005] [Accepted: 05/12/2005] [Indexed: 11/23/2022] Open
Abstract
Growth cones use cues in their environment in order to grow in a directed fashion to their targets. In Xenopus laevis, fibroblast growth factors (FGFs) participate in retinal ganglion cell (RGC) axon guidance in vivo and in vitro. The main intracellular signaling cascades known to act downstream of the FGF receptor include the mitogen-activated protein kinase (MAPK), phospholipase Cgamma (PLCgamma) and phosphotidylinositol 3-kinase (PI3K) pathways. We used pharmacological inhibitors to identify the signaling cascade(s) responsible for FGF-2-stimulated RGC axon extension and chemorepulsion. The MAPK, PI3K and PLCgamma pathways were blocked by U0126, LY249002 and U73122, respectively. D609 was used to test a role for the phosphotidylcholine-PLC (PC-PLC) pathway. We determined that the MAPK and two PLC pathways are required for FGF-2 to stimulate RGC neurite extension in vitro, but the response of axons to FGF-2 applied asymmetrically to the growth cone depended only on the PLC pathways.
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Affiliation(s)
- C A Webber
- Genes and Development Research Group, University of Calgary, 3330 Hospital Drive, NW, Calgary, AB, Canada T2N 4N1
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Park K, Luo JM, Hisheh S, Harvey AR, Cui Q. Cellular mechanisms associated with spontaneous and ciliary neurotrophic factor-cAMP-induced survival and axonal regeneration of adult retinal ganglion cells. J Neurosci 2005; 24:10806-15. [PMID: 15574731 PMCID: PMC6730205 DOI: 10.1523/jneurosci.3532-04.2004] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
We have shown previously that intraocular elevation of cAMP using the cAMP analog 8-(4-chlorophenylthio)-cAMP (CPT-cAMP) failed to promote axonal regeneration of axotomized adult retinal ganglion cells (RGCs) into peripheral nerve (PN) grafts but significantly potentiated ciliary neurotrophic factor (CNTF)-induced axonal regeneration. Using the PN graft model, we now examine the mechanisms underlying spontaneous and CNTF/CPT-cAMP-induced neuronal survival and axonal regrowth. We found that blockade of the cAMP pathway executor protein kinase A (PKA) using the cell-permeable inhibitor KT5720 did not affect spontaneous survival and axonal regeneration but essentially abolished the CNTF/CPT-cAMP-induced RGC survival and axonal regeneration. Blockade of CNTF signaling pathways such as phosphotidylinositol 3-kinase (PI3K)/akt by 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002), mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) by 2-(2-diamino-3-methoxyphenyl-4H-1-benzopyran-4-one (PD98059), or Janus kinase (JAK)/signal transducer and activators of transcription (STAT3) by tyrphostin AG490 also blocked the CNTF/CPT-cAMP-dependent survival and regeneration effects. PKA activity assay and Western blots showed that KT5720, LY294002, and PD98059 almost completely inhibited PKA, PI3K/akt, and MAPK/ERK signal transduction, respectively, whereas AG490 substantially decreased JAK/STAT3 signal transduction. Intraocular injection of CPT-cAMP resulted in a small PKA-dependent increase in CNTF receptor alpha mRNA expression in the retinas, an effect that may facilitate CNTF action on survival and axonal regeneration. Surprisingly, in the absence of CNTF/CPT-cAMP, LY294002, PD98059, and AG490, but not KT5720, significantly enhanced spontaneous RGC survival, suggesting differential roles of these pathways in RGC survival under different conditions. Our data suggest that CNTF/CPT-cAMP-induced RGC survival and axonal regeneration are a result of multiple pathway actions, with PKA as an essential component, but that these pathways can function in an antagonistic manner under different conditions.
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Affiliation(s)
- Kevin Park
- School of Anatomy and Human Biology and Western Australian Institute for Medical Research, The University of Western Australia, Crawley, Perth WA 6009, Australia
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Gu Z, Jiang Q, Fu AKY, Ip NY, Yan Z. Regulation of NMDA receptors by neuregulin signaling in prefrontal cortex. J Neurosci 2005; 25:4974-84. [PMID: 15901778 PMCID: PMC6724849 DOI: 10.1523/jneurosci.1086-05.2005] [Citation(s) in RCA: 164] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2004] [Revised: 04/13/2005] [Accepted: 04/13/2005] [Indexed: 11/21/2022] Open
Abstract
Recent linkage studies have identified a significant association of the neuregulin gene with schizophrenia, but how neuregulin is involved in schizophrenia is primarily unknown. Aberrant NMDA receptor functions have been implicated in the pathophysiology of schizophrenia. Therefore, we hypothesize that neuregulin, which is present in glutamatergic synaptic vesicles, may affect NMDA receptor functions via actions on its ErbB receptors enriched in postsynaptic densities, hence participating in emotional regulation and cognitive processes that are impaired in schizophrenia. To test this, we examined the regulation of NMDA receptor currents by neuregulin signaling pathways in prefrontal cortex (PFC), a prominent area affected in schizophrenia. We found that bath perfusion of neuregulin significantly reduced whole-cell NMDA receptor currents in acutely isolated and cultured PFC pyramidal neurons and decreased NMDA receptor-mediated EPSCs in PFC slices. The effect of neuregulin was mainly blocked by application of the ErbB receptor tyrosine kinase inhibitor, phospholipase C (PLC) inhibitor, IP3 receptor (IP3R) antagonist, or Ca2+ chelators. The neuregulin regulation of NMDA receptor currents was also markedly attenuated in cultured neurons transfected with mutant forms of Ras or a dominant-negative form of MEK1 (mitogen-activated protein kinase kinase 1). Moreover, the neuregulin effect was prevented by agents that stabilize or disrupt actin polymerization but not by agents that interfere with microtubule assembly. Furthermore, neuregulin treatment increased the abundance of internalized NMDA receptors in cultured PFC neurons, which was also sensitive to agents affecting actin cytoskeleton. Together, our study suggests that both PLC/IP3R/Ca2+ and Ras/MEK/ERK (extracellular signal-regulated kinase) signaling pathways are involved in the neuregulin-induced reduction of NMDA receptor currents, which is likely through enhancing NR1 internalization via an actin-dependent mechanism.
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Affiliation(s)
- Zhenglin Gu
- Department of Physiology and Biophysics, State University of New York at Buffalo, School of Medicine and Biomedical Sciences, Buffalo, New York 14214, USA
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Naska S, Cenni MC, Menna E, Maffei L. ERK signaling is required for eye-specific retino-geniculate segregation. Development 2004; 131:3559-70. [PMID: 15215205 DOI: 10.1242/dev.01212] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the mammalian visual system, retinal ganglion cell (RGC) projections from each eye, initially intermixed within the dorsal-lateral geniculate nucleus (dLGN), become segregated during the early stages of development, occupying distinct eye-specific layers. Electrical activity has been suggested to play a role in this process; however, the cellular mechanisms underlying eye-specific segregation are not yet defined. It is known that electrical activity is among the strongest activators of the extracellular signal-regulated kinase (ERK) pathway. Moreover, the ERK pathway is involved in the plasticity of neural connections during development. We examine the role of ERK in the segregation of retinal afferents into eye-specific layers in the dLGN. The activation of this signaling cascade was selectively blocked along the retino-thalamic circuitry by specific inhibitors, and the distribution of RGC fibers in the dLGN was studied. Our results demonstrate that the blockade of ERK signaling prevents eye-specific segregation in the dLGN, providing evidence that ERK pathway is required for the proper development of retino-geniculate connections. Of particular interest is the finding that ERK mediates this process both at the retinal and geniculate level.
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Affiliation(s)
- Sibel Naska
- Scuola Normale Superiore, piazza dei Cavalieri 7, 56100 Pisa, Italy.
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