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Mickael ME, Kubick N, Dragan M, Atanasov AG, Ławiński M, Paszkiewicz J, Horbańczuk JO, Religa P, Thorne A, Sacharczuk M. The impact of BDNF and CD4 + T cell crosstalk on depression. Immunol Res 2024:10.1007/s12026-024-09514-4. [PMID: 38980567 DOI: 10.1007/s12026-024-09514-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Accepted: 06/28/2024] [Indexed: 07/10/2024]
Affiliation(s)
- Michel-Edwar Mickael
- Institute of Genetics and Animal Biotechnology of the Polish Academy of Sciences, 05-552, JastrzebiecMagdalenka, Poland.
| | - Norwin Kubick
- Department of Biology, Institute of Plant Science and Microbiology, University of Hamburg, Ohnhorststr. 18, 22609, Hamburg, Germany
| | - Małgorzata Dragan
- Faculty of Psychology, University of Warsaw, Krakowskie Przedmieście26/28, 00-927, Warsaw, Poland
| | - Atanas G Atanasov
- Institute of Genetics and Animal Biotechnology of the Polish Academy of Sciences, 05-552, JastrzebiecMagdalenka, Poland
- Ludwig Boltzmann Institute Digital Health and Patient Safety, Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria
| | - Michał Ławiński
- Department of General, Gastroenterology and Oncologic Surgery, Medical University of Warsaw, Banacha 1a, 02-097, Warsaw, Poland
| | - Justyna Paszkiewicz
- Department of Health, John Paul II University of Applied Sciences in Biala Podlaska, Sidorska 95/97, 21-500, Biała Podlaska, Poland
| | - Jarosław Olav Horbańczuk
- Institute of Genetics and Animal Biotechnology of the Polish Academy of Sciences, 05-552, JastrzebiecMagdalenka, Poland
| | - Piotr Religa
- Department of Medicine, Karolinska Institute, 171 77, Solna, Sweden
| | - Ana Thorne
- Medical Faculty, University of Nis, Bulevar Dr Zorana Djidjica 81, 18000, Nis, Serbia
| | - Mariusz Sacharczuk
- Institute of Genetics and Animal Biotechnology of the Polish Academy of Sciences, 05-552, JastrzebiecMagdalenka, Poland.
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de Melo PS, Parente J, Rebello-Sanchez I, Marduy A, Gianlorenco AC, Kyung Kim C, Choi H, Song JJ, Fregni F. Understanding the Neuroplastic Effects of Auricular Vagus Nerve Stimulation in Animal Models of Stroke: A Systematic Review and Meta-Analysis. Neurorehabil Neural Repair 2023; 37:564-576. [PMID: 37272448 DOI: 10.1177/15459683231177595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
BACKGROUND Transauricular vagus nerve stimulation (taVNS) is being studied as a feasible intervention for stroke, but the mechanisms by which this non-invasive technique acts in the cortex are still broadly unknown. OBJECTIVES This study aimed to systematically review the current pre-clinical evidence in the auricular vagus nerve stimulation (aVNS) neuroplastic effects in stroke. METHODS We searched, in December of 2022, in Medline, Cochrane, Embase, and Lilacs databases. The authors executed the extraction of the data on Excel. The risk of bias was evaluated by adapted Cochrane Collaboration's tool for animal studies (SYRCLES's RoB tool). RESULTS A total of 8 studies published between 2015 and 2022 were included in this review, including 391 animal models. In general, aVNS demonstrated a reduction in neurological deficits (SMD = -1.97, 95% CI -2.57 to -1.36, I2 = 44%), in time to perform the adhesive removal test (SMD = -2.26, 95% CI -4.45 to -0.08, I2 = 81%), and infarct size (SMD = -1.51, 95% CI -2.42 to -0.60, I2 = 58%). Regarding the neuroplasticity markers, aVNS showed to increase microcapillary density, CD31 proliferation, and BDNF protein levels and RNA expression. CONCLUSIONS The studies analyzed show a trend of results that demonstrate a significant effect of the auricular vagal nerve stimulation in stroke animal models. Although the aggregated results show high heterogeneity and high risk of bias. More studies are needed to create solid conclusions.
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Affiliation(s)
- Paulo S de Melo
- Department of Medicine, Escola Bahiana de Medicina e Saúde Pública, Salvador, Bahia, Brazil
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - João Parente
- Department of Medicine, Escola Bahiana de Medicina e Saúde Pública, Salvador, Bahia, Brazil
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Ingrid Rebello-Sanchez
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Universidade Federal da Bahia, Salvador, Bahia, Brazil
| | - Anna Marduy
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- União Metropolitana de Ensino e Cultura (UNIME) Salvador, Bahia, Brazil
| | - Anna Carolyna Gianlorenco
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Physical Therapy, Federal University of Sao Carlos, Sao Carlos, Brazil
| | - Chi Kyung Kim
- Department of Neurology, Korea University Guro Hospital, Seoul, Republic of Korea
| | - Hyuk Choi
- Department of Medical Sciences, Graduate School of Medicine, Korea University, Seoul, Republic of Korea
- Neurive Co., Ltd., Gimhae, Republic of Korea
| | - Jae-Jun Song
- Neurive Co., Ltd., Gimhae, Republic of Korea
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University Medical Center, Seoul, Republic of Korea
| | - Felipe Fregni
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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Huang J, Fan H, Chen YM, Wang CN, Guan W, Li WY, Shi TS, Chen WJ, Zhu BL, Liu JF, Jiang B. The salt-inducible kinases inhibitor HG-9-91-01 exhibits antidepressant-like actions in mice exposed to chronic unpredictable mild stress. Neuropharmacology 2023; 227:109437. [PMID: 36702294 DOI: 10.1016/j.neuropharm.2023.109437] [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: 08/23/2022] [Revised: 01/16/2023] [Accepted: 01/21/2023] [Indexed: 01/24/2023]
Abstract
Major depressive disorder is a frequently occurring neuropsychiatric disorder throughout the world. However, the limited and delayed therapeutic efficacy of monoaminergic medications has led to intensive research efforts to develop novel antidepressants. We have previously demonstrated that hippocampal salt-inducible kinase 2 (SIK2) plays a role in the pathogenesis of depression via regulating the downstream CREB-regulated transcription coactivator 1 (CRTC1)-cAMP response element-binding protein (CREB)-brain derived neurotrophic factor (BDNF) pathway. HG-9-91-01 is a potent and selective inhibitor of salt-inducible kinases (SIKs). The present study aims to explore whether HG-9-91-01 has antidepressant-like actions in male C57BL/6J mice. The chronic unpredictable mild stress (CUMS) model of depression, various behavioral tests, western blotting, co-immunoprecipitation, immunofluorescence, stereotactic infusion, and viral-mediated genetic knockdown were used together. It was found that hippocampal infusion of HG-9-91-01 induced significant antidepressant-like effects in the CUMS model, accompanied with preventing the enhancement of CUMS on the hippocampal SIK2 expression and cytoplasmic translocation of CRTC1. HG-9-91-01 treatment also reversed the decreasing effects of CUMS on the BDNF signaling cascade and adult neurogenesis in the hippocampus. Moreover, the antidepressant-like actions of HG-9-91-01 in mice required the hippocampal CRTC1-CREB-BDNF pathway. In conclusion, HG-9-91-01 has potential of being a novel antidepressant candidate.
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Affiliation(s)
- Jie Huang
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China
| | - Hua Fan
- The First Affiliated Hospital, College of Clinical Medicine of Henan University of Science and Technology, Luoyang, 471000, Henan, China
| | - Yan-Mei Chen
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China
| | - Cheng-Niu Wang
- Basic Medical Research Centre, Medical College, Nantong University, Nantong, 226001, Jiangsu, China
| | - Wei Guan
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China
| | - Wei-Yu Li
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China
| | - Tian-Shun Shi
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China
| | - Wei-Jia Chen
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China
| | - Bao-Lun Zhu
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China
| | - Jian-Feng Liu
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China.
| | - Bo Jiang
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China.
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Mousa HH, Sharawy MH, Nader MA. Empagliflozin enhances neuroplasticity in rotenone-induced parkinsonism: Role of BDNF, CREB and Npas4. Life Sci 2022; 312:121258. [PMID: 36462721 DOI: 10.1016/j.lfs.2022.121258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 12/03/2022]
Abstract
AIMS Parkinsonism is characterized by degeneration of dopaminergic neurons and impairment in neuroplasticity. Empagliflozin (EMPA) is an anti-diabetic drug that has been shown to improve cognitive dysfunctions and exerted antioxidant and anti-inflammatory effects in different models. This study aimed to determine the neuroprotective effects of EMPA against rotenone (ROT)-induced parkinsonism. MAIN METHODS ROT (1.5 mg/kg) was injected subcutaneously three times per week for two successive weeks. Mice were treated with EMPA (3 and 10 mg/kg, orally) for one week prior ROT administration and for another two weeks along with ROT. After that, motor functions and histopathological changes were assessed, and brains were isolated for biochemical analyses and immunohistochemical investigation. KEY FINDINGS Results indicated that, in a dose dependent manner, EMPA improved motor functions and histopathological changes induced by ROT, increased brain content of reduced glutathione (GSH), dopamine (DA), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), nuclear factor erythroid 2-related factor 2 (Nrf2), inositol trisphosphate (IP3), calcium (Ca2+), calcium/calmodulin-dependent protein kinase type IV (CaMKIV) and phospho-Protein kinase B (p-Akt) levels compared to ROT group. Additionally, EMPA decreased the levels of malondialdehyde (MDA), and tumor necrosis factor-α (TNF-α), and inactivated glycogen synthase kinase-3 beta (GSK-3β). Improvement in neuroplasticity was also observed indicated by elevation in brain derived neurotrophic factor (BDNF), cAMP response element-binding protein (CREB), and neuronal PAS domain Protein 4 (Npas4). SIGNIFICANCE EMPA improved motor functions possibly through improving neuroplasticity markers and antioxidant, anti-inflammatory, and neuroprotective effects in a dose dependent manner.
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Affiliation(s)
- Hager H Mousa
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
| | - Maha H Sharawy
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt.
| | - Manar A Nader
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
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Cheon S, Culver AM, Bagnell AM, Ritchie FD, Vacharasin JM, McCord MM, Papendorp CM, Chukwurah E, Smith AJ, Cowen MH, Moreland TA, Ghate PS, Davis SW, Liu JS, Lizarraga SB. Counteracting epigenetic mechanisms regulate the structural development of neuronal circuitry in human neurons. Mol Psychiatry 2022; 27:2291-2303. [PMID: 35210569 PMCID: PMC9133078 DOI: 10.1038/s41380-022-01474-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 02/02/2022] [Indexed: 01/23/2023]
Abstract
Autism spectrum disorders (ASD) are associated with defects in neuronal connectivity and are highly heritable. Genetic findings suggest that there is an overrepresentation of chromatin regulatory genes among the genes associated with ASD. ASH1 like histone lysine methyltransferase (ASH1L) was identified as a major risk factor for ASD. ASH1L methylates Histone H3 on Lysine 36, which is proposed to result primarily in transcriptional activation. However, how mutations in ASH1L lead to deficits in neuronal connectivity associated with ASD pathogenesis is not known. We report that ASH1L regulates neuronal morphogenesis by counteracting the catalytic activity of Polycomb Repressive complex 2 group (PRC2) in stem cell-derived human neurons. Depletion of ASH1L decreases neurite outgrowth and decreases expression of the gene encoding the neurotrophin receptor TrkB whose signaling pathway is linked to neuronal morphogenesis. The neuronal morphogenesis defect is overcome by inhibition of PRC2 activity, indicating that a balance between the Trithorax group protein ASH1L and PRC2 activity determines neuronal morphology. Thus, our work suggests that ASH1L may epigenetically regulate neuronal morphogenesis by modulating pathways like the BDNF-TrkB signaling pathway. Defects in neuronal morphogenesis could potentially impair the establishment of neuronal connections which could contribute to the neurodevelopmental pathogenesis associated with ASD in patients with ASH1L mutations.
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Affiliation(s)
- Seonhye Cheon
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Allison M Culver
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Anna M Bagnell
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Foster D Ritchie
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Janay M Vacharasin
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Mikayla M McCord
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Carin M Papendorp
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA
| | - Evelyn Chukwurah
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Austin J Smith
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Mara H Cowen
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Trevor A Moreland
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Pankaj S Ghate
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Shannon W Davis
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Judy S Liu
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA
- Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science and Brown Institute for Translational Science, Brown University, Providence, RI, USA
- Department of Neurology, Rhode Island Hospital and Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Sofia B Lizarraga
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA.
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA.
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Kaltezioti V, Foskolou IP, Lavigne MD, Ninou E, Tsampoula M, Fousteri M, Margarity M, Politis PK. Prox1 inhibits neurite outgrowth during central nervous system development. Cell Mol Life Sci 2021; 78:3443-3465. [PMID: 33247761 PMCID: PMC11072475 DOI: 10.1007/s00018-020-03709-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 11/06/2020] [Accepted: 11/11/2020] [Indexed: 12/24/2022]
Abstract
During central nervous system (CNS) development, proper and timely induction of neurite elongation is critical for generating functional, mature neurons, and neuronal networks. Despite the wealth of information on the action of extracellular cues, little is known about the intrinsic gene regulatory factors that control this developmental decision. Here, we report the identification of Prox1, a homeobox transcription factor, as a key player in inhibiting neurite elongation. Although Prox1 promotes acquisition of early neuronal identity and is expressed in nascent post-mitotic neurons, it is heavily down-regulated in the majority of terminally differentiated neurons, indicating a regulatory role in delaying neurite outgrowth in newly formed neurons. Consistently, we show that Prox1 is sufficient to inhibit neurite extension in mouse and human neuroblastoma cell lines. More importantly, Prox1 overexpression suppresses neurite elongation in primary neuronal cultures as well as in the developing mouse brain, while Prox1 knock-down promotes neurite outgrowth. Mechanistically, RNA-Seq analysis reveals that Prox1 affects critical pathways for neuronal maturation and neurite extension. Interestingly, Prox1 strongly inhibits many components of Ca2+ signaling pathway, an important mediator of neurite extension and neuronal maturation. In accordance, Prox1 represses Ca2+ entry upon KCl-mediated depolarization and reduces CREB phosphorylation. These observations suggest that Prox1 acts as a potent suppressor of neurite outgrowth by inhibiting Ca2+ signaling pathway. This action may provide the appropriate time window for nascent neurons to find the correct position in the CNS prior to initiation of neurites and axon elongation.
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Affiliation(s)
- Valeria Kaltezioti
- Center for Basic Research, Biomedical Research Foundation of the Academy of Athens, 4 Soranou Efesiou Street, 115 27, Athens, Greece
| | - Iosifina P Foskolou
- Center for Basic Research, Biomedical Research Foundation of the Academy of Athens, 4 Soranou Efesiou Street, 115 27, Athens, Greece
| | - Matthieu D Lavigne
- Institute for Fundamental Biomedical Research, BSRC 'Alexander Fleming', 34 Fleming Street, Vari, 16672, Athens, Greece
| | - Elpinickie Ninou
- Center for Basic Research, Biomedical Research Foundation of the Academy of Athens, 4 Soranou Efesiou Street, 115 27, Athens, Greece
| | - Matina Tsampoula
- Center for Basic Research, Biomedical Research Foundation of the Academy of Athens, 4 Soranou Efesiou Street, 115 27, Athens, Greece
| | - Maria Fousteri
- Institute for Fundamental Biomedical Research, BSRC 'Alexander Fleming', 34 Fleming Street, Vari, 16672, Athens, Greece
| | - Marigoula Margarity
- Laboratory of Human and Animal Physiology, Department of Biology, School of Natural Sciences, University of Patras, 26500, Rio Achaias, Greece
| | - Panagiotis K Politis
- Center for Basic Research, Biomedical Research Foundation of the Academy of Athens, 4 Soranou Efesiou Street, 115 27, Athens, Greece.
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7
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Ampofo E, Nalbach L, Menger MD, Laschke MW. Regulatory Mechanisms of Somatostatin Expression. Int J Mol Sci 2020; 21:ijms21114170. [PMID: 32545257 PMCID: PMC7312888 DOI: 10.3390/ijms21114170] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 06/07/2020] [Accepted: 06/09/2020] [Indexed: 12/17/2022] Open
Abstract
Somatostatin is a peptide hormone, which most commonly is produced by endocrine cells and the central nervous system. In mammals, somatostatin originates from pre-prosomatostatin and is processed to a shorter form, i.e., somatostatin-14, and a longer form, i.e., somatostatin-28. The two peptides repress growth hormone secretion and are involved in the regulation of glucagon and insulin synthesis in the pancreas. In recent years, the processing and secretion of somatostatin have been studied intensively. However, little attention has been paid to the regulatory mechanisms that control its expression. This review provides an up-to-date overview of these mechanisms. In particular, it focuses on the role of enhancers and silencers within the promoter region as well as on the binding of modulatory transcription factors to these elements. Moreover, it addresses extracellular factors, which trigger key signaling pathways, leading to an enhanced somatostatin expression in health and disease.
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Affiliation(s)
- Emmanuel Ampofo
- Correspondence: ; Tel.: +49-6841-162-6561; Fax: +49-6841-162-6553
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8
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Li J, Zhang Q, Li S, Niu L, Ma J, Wen L, Zhang L, Li C. α7nAchR mediates transcutaneous auricular vagus nerve stimulation-induced neuroprotection in a rat model of ischemic stroke by enhancing axonal plasticity. Neurosci Lett 2020; 730:135031. [DOI: 10.1016/j.neulet.2020.135031] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 04/30/2020] [Accepted: 05/01/2020] [Indexed: 12/20/2022]
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Gao X, Zhang X, Cui L, Chen R, Zhang C, Xue J, Zhang L, He W, Li J, Wei S, Wei M, Cui H. Ginsenoside Rb1 Promotes Motor Functional Recovery and Axonal Regeneration in Post-stroke Mice through cAMP/PKA/CREB Signaling Pathway. Brain Res Bull 2019; 154:51-60. [PMID: 31715311 DOI: 10.1016/j.brainresbull.2019.10.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 09/29/2019] [Accepted: 10/19/2019] [Indexed: 11/29/2022]
Abstract
The central nervous system (CNS) has a poor self-repairing capability after injury because of the inhibition of axonal regeneration by many myelin-associated inhibitory factors. Therefore, ischemic stroke usually leads to disability. Previous studies reported that Ginsenoside Rb1 (GRb1) plays a role in neuronal protection in acute phase after ischemic stroke, but its efficacy in post-stroke and the underlying mechanism are not clear. Recent evidences demonstrated GRb1 promotes neurotransmitter release through the cAMP-depend protein kinase A (PKA) pathway, which is related to axonal regeneration. The present study aimed to determine whether GRb1 improves long-term motor functional recovery and promotes cortical axon regeneration in post-stroke. Adult male C57BL/6 mice were subjected to distal middle cerebral artery occlusion (dMCAO). GRb1 solution (5 mg/ml) or equal volume of normal saline was injected intraperitoneally for the first time at 24 h after surgery, and then daily injected until day 14. Day 3, 7, 14 and 28 after dMCAO were used as observation time points. Motor functional recovery was assessed with Rota-rod test and grid walking task. The expression of growth-associated protein 43 (GAP43) and biotinylated dextran amine (BDA) was measured to evaluate axonal regeneration. The levels of cyclic AMP (cAMP) and PKA were measured by Elisa, PKAc and phosphorylated cAMP response element protein (pCREB) were determined by western blot. Our results shown that GRb1 treatment improved motor function and increased the expression of GAP43 and BDA in ipsilesional and contralateral cortex. GRb1 significantly elevated cAMP and PKA, increased the protein expression of PKAc and pCREB. However, the effects of GRb1 were eliminated by H89 intervention (a PKA inhibitor). These results suggested that GRb1 improved functional recovery in post-stroke by stimulating axonal regeneration and brain repair. The underlying mechanism might be up-regulating the expression of cAMP/PKA/CREB pathway.
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Affiliation(s)
- Xuan Gao
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
| | - Xiangjian Zhang
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China; Hebei Key Laboratory of Vascular Homeostasis and Hebei Collaborative Innovation Center for Cardio-cerebrovascular Disease, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China.
| | - Lili Cui
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China; Hebei Key Laboratory of Vascular Homeostasis and Hebei Collaborative Innovation Center for Cardio-cerebrovascular Disease, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
| | - Rong Chen
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China; Hebei Key Laboratory of Vascular Homeostasis and Hebei Collaborative Innovation Center for Cardio-cerebrovascular Disease, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
| | - Cong Zhang
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
| | - Jing Xue
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
| | - Lan Zhang
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
| | - Weiliang He
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
| | - Jiamin Li
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
| | - Shanshan Wei
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
| | - Mengmeng Wei
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
| | - Hemei Cui
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
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Jiang B, Wang H, Wang JL, Wang YJ, Zhu Q, Wang CN, Song L, Gao TT, Wang Y, Meng GL, Wu F, Ling Y, Zhang W, Li JX. Hippocampal Salt-Inducible Kinase 2 Plays a Role in Depression via the CREB-Regulated Transcription Coactivator 1-cAMP Response Element Binding-Brain-Derived Neurotrophic Factor Pathway. Biol Psychiatry 2019; 85:650-666. [PMID: 30503507 DOI: 10.1016/j.biopsych.2018.10.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 10/03/2018] [Accepted: 10/04/2018] [Indexed: 12/28/2022]
Abstract
BACKGROUND Developing novel pharmacological targets beyond monoaminergic systems is now a popular strategy for finding new ways to treat depression. Salt-inducible kinase (SIK) is a kinase that regulates the nuclear translocation of cyclic adenosine monophosphate response element binding protein (CREB)-regulated transcription coactivator (CRTC) by phosphorylation. Here, we hypothesize that dysfunction of the central SIK-CRTC system may contribute to the pathogenesis of depression. METHODS Chronic social defeat stress (CSDS) and chronic unpredictable mild stress (CUMS) models of depression, various behavioral tests, viral-mediated gene transfer, Western blotting, coimmunoprecipitation, quantitative real-time reverse transcription polymerase chain reaction, and immunohistochemistry were used in this study (for in vivo studies, n = 10; for in vitro studies, n = 5). RESULTS Both CSDS and CUMS markedly increased the expression of hippocampal SIK2, which reduced CRTC1 nuclear translocation and binding of CRTC1 and CREB in the hippocampus. Genetic overexpression of hippocampal SIK2 in naïve mice simulated chronic stress, inducing depressive-like behaviors in the forced swim test, tail suspension test, sucrose preference test, and social interaction test, as well as decreasing the brain-derived neurotrophic factor signaling cascade and neurogenesis in the hippocampus. In contrast, genetic knockdown and knockout of hippocampal SIK2 protected against CSDS and CUMS, exerting significant antidepressant-like effects that were mediated via the downstream CRTC1-CREB-brain-derived neurotrophic factor pathway. Moreover, fluoxetine, venlafaxine, and mirtazapine all significantly restored the effects of CSDS and CUMS on the hippocampal SIK2-CRTC1 pathway, which was necessary for their antidepressant actions. CONCLUSIONS The hippocampal SIK2-CRTC1 pathway is involved in the pathogenesis of depression, and hippocampal SIK2 could be a novel target for the development of antidepressants.
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Affiliation(s)
- Bo Jiang
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu, China; Jiangsu Province Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China.
| | - Hao Wang
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu, China; Jiangsu Province Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Jin-Liang Wang
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu, China; Jiangsu Province Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Ying-Jie Wang
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu, China; Jiangsu Province Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Qing Zhu
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu, China; Jiangsu Province Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Cheng-Niu Wang
- Basic Medical Research Centre, Medical College, Nantong University, Nantong, Jiangsu, China
| | - Lu Song
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu, China; Jiangsu Province Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Ting-Ting Gao
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu, China; Jiangsu Province Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Yuan Wang
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu, China; Jiangsu Province Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Guo-Liang Meng
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu, China; Jiangsu Province Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Feng Wu
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu, China; Jiangsu Province Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Yong Ling
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu, China; Jiangsu Province Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Wei Zhang
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu, China; Jiangsu Province Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Jun-Xu Li
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu, China.
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Ding B, Dobner PR, Mullikin-Kilpatrick D, Wang W, Zhu H, Chow CW, Cave JW, Gronostajski RM, Kilpatrick DL. BDNF activates an NFI-dependent neurodevelopmental timing program by sequestering NFATc4. Mol Biol Cell 2018; 29:975-987. [PMID: 29467254 PMCID: PMC5896935 DOI: 10.1091/mbc.e16-08-0595] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 02/07/2018] [Accepted: 02/13/2018] [Indexed: 12/20/2022] Open
Abstract
We show that BDNF regulates the timing of neurodevelopment via a novel mechanism of extranuclear sequestration of NFATc4 in Golgi. This leads to accelerated derepression of an NFI temporal occupancy gene program in cerebellar granule cells that includes Bdnf itself, revealing an autoregulatory loop within the program driven by BDNF and NFATc4.
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Affiliation(s)
- Baojin Ding
- Department of Microbiology and Physiological Systems and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01605-2324
| | - Paul R. Dobner
- Department of Microbiology and Physiological Systems and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01605-2324
| | - Debra Mullikin-Kilpatrick
- Department of Microbiology and Physiological Systems and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01605-2324
| | - Wei Wang
- Department of Microbiology and Physiological Systems and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01605-2324
| | - Hong Zhu
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, NY 10461
| | - Chi-Wing Chow
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, NY 10461
| | - John W. Cave
- Burke Medical Research Institute, White Plains, NY 10605
- Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065
| | - Richard M. Gronostajski
- Department of Biochemistry, Program in Neuroscience and Developmental Genomics Group, New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY 14203
| | - Daniel L. Kilpatrick
- Department of Microbiology and Physiological Systems and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01605-2324
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12
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Kramer B, Tropitzsch A, Müller M, Löwenheim H. Myelin-induced inhibition in a spiral ganglion organ culture - Approaching a natural environment in vitro. Neuroscience 2017; 357:75-83. [PMID: 28596120 DOI: 10.1016/j.neuroscience.2017.05.053] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 05/12/2017] [Accepted: 05/30/2017] [Indexed: 12/23/2022]
Abstract
The performance of a cochlear implant depends on the defined interaction between afferent neurons of the spiral ganglion and the inserted electrode. Neurite outgrowth can be induced by neurotrophins such as brain-derived neurotrophic factor (BDNF) via tropomyosin kinase receptor B (TrkB). However, neurotrophin signaling through the p75 neurotrophin receptor (p75) inhibits neurite outgrowth in the presence of myelin. Organotypic cultures derived from postnatal (P3-5) mice were used to study myelin-induced inhibition in the cochlear spiral ganglion. Neurite outgrowth was analyzed and quantified utilizing an adapted Sholl analysis. Stimulation of neurite outgrowth was quantified after application of BDNF, the selective TrkB agonist 7,8-dihydroxyflavone (7,8-DHF) and a selective inhibitor of the Rho-associated kinase (Y27632), which inhibits the p75 pathway. Myelin-induced inhibition was assessed by application of myelin-associated glycoprotein (MAG-Fc) to stimulate the inhibitory p75 pathway. Inhibition of neurite outgrowth was achieved by the selective TrkB inhibitor K252a. Stimulation of neurite outgrowth was observed after treatment with BDNF, 7,8 DHF and a combination of BDNF and Y27632. The 7,8-DHF-induced growth effects could be inhibited by K252a. Furthermore, inhibition of neurite outgrowth was observed after supplementation with MAG-Fc. Myelin-induced inhibition could be overcome by 7,8-DHF and the combination of BDNF and Y27632. In this study, myelin-induced inhibition of neurite outgrowth was established in a spiral ganglion model. We reveal that 7,8-DHF is a viable novel compound for the stimulation of neurite outgrowth in a myelin-induced inhibitory environment. The combination of TrkB stimulation and ROCK inhibition can be used to overcome myelin inhibition.
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Affiliation(s)
- Benedikt Kramer
- Department of Otorhinolaryngology - Head and Neck Surgery, Hearing Research Centre Tübingen (THRC), University Tübingen, Germany
| | - Anke Tropitzsch
- Department of Otorhinolaryngology - Head and Neck Surgery, Hearing Research Centre Tübingen (THRC), University Tübingen, Germany
| | - Marcus Müller
- Department of Otorhinolaryngology - Head and Neck Surgery, Hearing Research Centre Tübingen (THRC), University Tübingen, Germany.
| | - Hubert Löwenheim
- Department of Otorhinolaryngology - Head and Neck Surgery, Hearing Research Centre Tübingen (THRC), University Tübingen, Germany
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13
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Alkadhi KA. Exercise as a Positive Modulator of Brain Function. Mol Neurobiol 2017; 55:3112-3130. [PMID: 28466271 DOI: 10.1007/s12035-017-0516-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Accepted: 04/04/2017] [Indexed: 12/24/2022]
Abstract
Various forms of exercise have been shown to prevent, restore, or ameliorate a variety of brain disorders including dementias, Parkinson's disease, chronic stress, thyroid disorders, and sleep deprivation, some of which are discussed here. In this review, the effects on brain function of various forms of exercise and exercise mimetics in humans and animal experiments are compared and discussed. Possible mechanisms of the beneficial effects of exercise including the role of neurotrophic factors and others are also discussed.
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Affiliation(s)
- Karim A Alkadhi
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX, 77204, USA.
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14
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Yan X, Liu J, Ye Z, Huang J, He F, Xiao W, Hu X, Luo Z. CaMKII-Mediated CREB Phosphorylation Is Involved in Ca2+-Induced BDNF mRNA Transcription and Neurite Outgrowth Promoted by Electrical Stimulation. PLoS One 2016; 11:e0162784. [PMID: 27611779 PMCID: PMC5017744 DOI: 10.1371/journal.pone.0162784] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 08/29/2016] [Indexed: 11/19/2022] Open
Abstract
Electrical stimulation (ES)-triggered up-regulation of brain-derived neurotrophic factor (BDNF) and neurite outgrowth in cultured rat postnatal dorsal root ganglion neurons (DRGNs) is calcium (Ca2+)-dependent. The effects of increased Ca2+ on BDNF up-regulation and neurite outgrowth remain unclear. We showed here that ES increased phosphorylation of the cAMP-response element binding protein (CREB). Blockade of Ca2+ suppressed CREB phosphorylation and neurite outgrowth. Down-regulation of phosphorylated (p)-CREB reduced BDNF transcription and neurite outgrowth triggered by ES. Furthermore, blockade of calmodulin-dependent protein kinase II (CaMKII) using the inhibitors KN93 or KN62 reduced p-CREB, and specific knockdown of the CaMKIIα or CaMKIIβ subunit was sufficient to suppress p-CREB. Recombinant BDNF or hyperforin reversed the effects of Ca2+ blockade and CaMKII knockdown. Taken together, these data establish a potential signaling pathway of Ca2+-CaMKII-CREB in neuronal activation. To our knowledge, this is the first report of the mechanisms of Ca2+-dependent BDNF transcription and neurite outgrowth triggered by ES. These findings might help further investigation of complex molecular signaling networks in ES-triggered nerve regeneration in vivo.
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Affiliation(s)
- Xiaodong Yan
- Department of Orthopaedics, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China
- Department of Orthopaedics, Tangdu Hospital, Fourth Military Medical University, Xi’an 710038, China
| | - Juanfang Liu
- Department of Clinical Aerospace Medicine, Fourth Military Medical University, Xi’an 710032, China
| | - Zhengxu Ye
- Department of Orthopaedics, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China
| | - Jinghui Huang
- Department of Orthopaedics, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China
| | - Fei He
- Department of Hereditary and Development, Basic Unit, Fourth Military Medical University, Xi’an 710032, China
| | - Wei Xiao
- Department of Orthopaedics, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China
| | - Xueyu Hu
- Department of Orthopaedics, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China
- * E-mail: (ZL); (XH)
| | - Zhuojing Luo
- Department of Orthopaedics, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China
- * E-mail: (ZL); (XH)
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15
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Ashokan A, Hegde A, Mitra R. Short-term environmental enrichment is sufficient to counter stress-induced anxiety and associated structural and molecular plasticity in basolateral amygdala. Psychoneuroendocrinology 2016; 69:189-96. [PMID: 27128967 DOI: 10.1016/j.psyneuen.2016.04.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 04/09/2016] [Accepted: 04/09/2016] [Indexed: 01/07/2023]
Abstract
Moderate levels of anxiety enable individual animals to cope with stressors through avoidance, and could be an adaptive trait. However, repeated stress exacerbates anxiety to pathologically high levels. Dendritic remodeling in the basolateral amygdala is proposed to mediate potentiation of anxiety after stress. Similarly, modulation of brain-derived neurotrophic factor is thought to be important for the behavioral effects of stress. In the present study, we investigate if relatively short periods of environmental enrichment in adulthood can confer resilience against stress-induced anxiety and concomitant changes in neuronal arborisation and brain derived neurotrophic factor within basolateral amygdala. Two weeks of environmental enrichment countermanded the propensity of increased anxiety following chronic immobilization stress. Environmental enrichment concurrently reduced dendritic branching and spine density of projection neurons of the basolateral amygdala. Moreover, stress increased abundance of BDNF mRNA in the basolateral amygdala in agreement with the dendritic hypertrophy post-stress and role of BDNF in promoting dendritic arborisation. In contrast, environmental enrichment prevented stress-induced rise in the BDNF mRNA abundance. Gain in body weights and adrenal weights remained unaffected by exposure to environmental enrichment. These observations suggest that a short period of environmental enrichment can provide resilience against maladaptive effects of stress on hormonal, neuronal and molecular mediators of anxiogenesis.
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Affiliation(s)
- Archana Ashokan
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore.
| | - Akshaya Hegde
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore.
| | - Rupshi Mitra
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore.
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16
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Yang T, Massa SM, Tran KC, Simmons DA, Rajadas J, Zeng AY, Jang T, Carsanaro S, Longo FM. A small molecule TrkB/TrkC neurotrophin receptor co-activator with distinctive effects on neuronal survival and process outgrowth. Neuropharmacology 2016; 110:343-361. [PMID: 27334657 DOI: 10.1016/j.neuropharm.2016.06.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 05/28/2016] [Accepted: 06/16/2016] [Indexed: 01/16/2023]
Abstract
Neurotrophin (NT) receptors are coupled to numerous signaling networks that play critical roles in neuronal survival and plasticity. Several non-peptide small molecule ligands have recently been reported that bind to and activate specific tropomyosin-receptor kinase (Trk) NT receptors, stimulate their downstream signaling, and cause biologic effects similar to, though not completely overlapping, those of the native NT ligands. Here, in silico screening, coupled with low-throughput neuronal survival screening, identified a compound, LM22B-10, that, unlike prior small molecule Trk ligands, binds to and activates TrkB as well as TrkC. LM22B-10 increased cell survival and strongly accelerated neurite outgrowth, superseding the effects of brain-derived neurotrophic factor (BDNF), NT-3 or the two combined. Additionally, unlike the NTs, LM22B-10 supported substantial early neurite outgrowth in the presence of inhibiting glycoproteins. Examination of the mechanisms of these actions suggested contributions of the activation of both Trks and differential interactions with p75(NTR), as well as a requirement for involvement of the Trk extracellular domain. In aged mice, LM22B-10 activated hippocampal and striatal TrkB and TrkC, and their downstream signaling, and increased hippocampal dendritic spine density. Thus, LM22B-10 may constitute a new tool for the study of TrkB and TrkC signaling and their interactions with p75(NTR), and provides groundwork for the development of ligands that stimulate unique combinations of Trk receptors and activity patterns for application to selected neuronal populations and deficits present in various disease states.
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Affiliation(s)
- Tao Yang
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Stephen M Massa
- Department of Neurology and Laboratory for Computational Neurochemistry and Drug Discovery, San Francisco Veterans Affairs Medical Center, and Dept. of Neurology, University of California, San Francisco, CA 94121, USA.
| | - Kevin C Tran
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Danielle A Simmons
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jayakumar Rajadas
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Anne Y Zeng
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Taichang Jang
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sara Carsanaro
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Frank M Longo
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA.
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17
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Blair JA, Bhatta S, McGee H, Casadesus G. Luteinizing hormone: Evidence for direct action in the CNS. Horm Behav 2015; 76:57-62. [PMID: 26172857 PMCID: PMC4741372 DOI: 10.1016/j.yhbeh.2015.06.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 07/06/2015] [Accepted: 07/07/2015] [Indexed: 01/09/2023]
Abstract
This article is part of a Special Issue "SBN 2014". Hormonal dysfunction due to aging, especially during menopause, plays a substantial role in cognitive decline as well as the progression and development of neurodegenerative diseases. The hypothalamic-pituitary-gonadal (HPG) axis has long been implicated in changes in behavior and neuronal morphology. Most notably, estrogens have proven beneficial in the healthy brain through a host of different mechanisms. Recently, luteinizing hormone (LH) has emerged as a candidate for further investigation for its role in the CNS. The basis of this is that both LH and the LH receptor are expressed in the brain, and serum levels of LH correlate with cognitive deficits and Alzheimer's disease (AD) incidence. The study of LH in cognition and AD primarily focuses on evaluating the effects of downregulation of this peptide. This literature has shown that decreasing peripheral LH, through a variety of pharmacological interventions, reduces cognitive deficits in ovariectomy and AD models. However, few studies have researched the direct actions of LH on neurons and glial cells. Here we summarize the role of luteinizing hormone in modulating cognition, and we propose a mechanism that underlies a role for brain LH in this process.
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Affiliation(s)
- Jeffrey A Blair
- School of Biomedical Sciences, Kent State University, Kent, OH, USA
| | - Sabina Bhatta
- School of Biomedical Sciences, Kent State University, Kent, OH, USA
| | - Henry McGee
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Gemma Casadesus
- Department of Biological Sciences, Kent State University, Kent, OH, USA.
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18
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Song W, Jin XA. Brain-derived neurotrophic factor inhibits neuromuscular junction maturation mediated by inTracellular Ca(2+) and Ca(2+)/calmodulin-dependent kinase. Muscle Nerve 2015; 53:593-7. [PMID: 26248508 DOI: 10.1002/mus.24793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 07/22/2015] [Accepted: 08/05/2015] [Indexed: 11/06/2022]
Abstract
INTRODUCTION Brain-derived neurotrophic factor (BDNF) inhibits neuromuscular junction (NMJ) maturation. In this study we investigated the underlying molecular mechanisms of this process. METHODS We used a patch-clamp technique to measure spontaneous synaptic currents (SSCs) from innervated muscle cells in Xenopus nerve-muscle cocultures. RESULTS In the presence of Ca(2+)/calmodulin-dependent kinase (CaMK) inhibitor KN93, SSC amplitude (226.3 ± 26.5 pA), frequency (30.9 ± 10.1 events/min), and percentage of bell-shaped amplitude distributions (47.1%) were reversed to control levels (286.7 ± 48.2 pA, 26.2 ± 5.8 events/min, and 47.1%, respectively). Depletion of intracellular Ca(2+) by BAPTA-AM or thapsigargin had similar reversal effects to KN93. In addition, cotreatment with both 2-APB (IP3 receptor inhibitor) and TMB-8 (ryanodine receptor inhibitor) also reversed the inhibitory effects of BDNF, as shown by the physiological parameters. CONCLUSIONS CaMK mediates the inhibitory effects of BDNF on NMJ maturation. Ca(2+) released from intracellular stores through either IP3 receptors or ryanodine receptors regulates neurotrophic actions on NMJ maturation.
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Affiliation(s)
- Wei Song
- Peking University Health Science Center, Mailbox 045, 38 Xueyuan Road, Haidian District, Beijing, 100191, China.,Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Xiwan Albert Jin
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
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19
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Zagaar MA, Dao AT, Alhaider IA, Alkadhi KA. Prevention by Regular Exercise of Acute Sleep Deprivation-Induced Impairment of Late Phase LTP and Related Signaling Molecules in the Dentate Gyrus. Mol Neurobiol 2015; 53:2900-2910. [PMID: 25902862 DOI: 10.1007/s12035-015-9176-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 04/13/2015] [Indexed: 01/12/2023]
Abstract
The dentate gyrus (DG) and CA1 regions of the hippocampus are intimately related physically and functionally, yet they react differently to insults. The purpose of this study was to determine the protective effects of regular treadmill exercise on late phase long-term potentiation (L-LTP) and its signaling cascade in the DG region of the hippocampus of rapid eye movement (REM) sleep-deprived rats. Adult Wistar rats ran on treadmills for 4 weeks then were acutely sleep deprived for 24 h using the modified multiple platform method. After sleep deprivation, the rats were anesthetized and L-LTP was induced in the DG region. Extracellular field potentials from the DG were recorded in vivo, and levels of L-LTP-related signaling proteins were assessed both before and after L-LTP expression using immunoblot analysis. Sleep deprivation reduced the basal levels of phosphorylated cAMP response element-binding protein (P-CREB) as well as other upstream modulators including calcium/calmodulin kinase IV (CaMKIV) and brain-derived neurotrophic factor (BDNF) in the DG of the hippocampus. Regular exercise prevented impairment of the basal levels of P-CREB and total CREB as well as those of CaMKIV in sleep-deprived animals. Furthermore, regular exercise prevented sleep deprivation-induced inhibition of L-LTP and post-L-LTP downregulation of P-CREB and BDNF levels in the DG. The current findings show that our exercise regimen prevents sleep deprivation-induced deficits in L-LTP as well as the basal and poststimulation levels of key signaling molecules.
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Affiliation(s)
- Munder A Zagaar
- Departmentof Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, TX, USA
| | - An T Dao
- Departmentof Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, TX, USA
| | - Ibrahim A Alhaider
- College of Clinical Pharmacy, King Faisal University, Al-Hofuf, Saudi Arabia
| | - Karim A Alkadhi
- Departmentof Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, TX, USA.
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20
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Hallaq R, Volpicelli F, Cuchillo-Ibanez I, Hooper C, Mizuno K, Uwanogho D, Causevic M, Asuni A, To A, Soriano S, Giese KP, Lovestone S, Killick R. The Notch intracellular domain represses CRE-dependent transcription. Cell Signal 2014; 27:621-9. [PMID: 25479589 DOI: 10.1016/j.cellsig.2014.11.034] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 11/27/2014] [Accepted: 11/27/2014] [Indexed: 12/25/2022]
Abstract
Members of the cyclic-AMP response-element binding protein (CREB) transcription factor family regulate the expression of genes needed for long-term memory formation. Loss of Notch impairs long-term, but not short-term, memory in flies and mammals. We investigated if the Notch-1 (N1) exerts an effect on CREB-dependent gene transcription. We observed that N1 inhibits CREB mediated activation of cyclic-AMP response element (CRE) containing promoters in a γ-secretase-dependent manner. We went on to find that the γ-cleaved N1 intracellular domain (N1ICD) sequesters nuclear CREB1α, inhibits cAMP/PKA-mediated neurite outgrowth and represses the expression of specific CREB regulated genes associated with learning and memory in primary cortical neurons. Similar transcriptional effects were observed with the N2ICD, N3ICD and N4ICDs. Together, these observations indicate that the effects of Notch on learning and memory are, at least in part, via an effect on CREB-regulated gene expression.
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Affiliation(s)
- Rania Hallaq
- King's College London, Institute of Psychiatry, Psychology and Neuroscience, De Crespigny Park, Denmark Hill, London SE5 8AF, UK
| | - Floriana Volpicelli
- Institute of Genetics and Biophysics "Adriano Buzzati-Traverso", CNR, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Inmaculada Cuchillo-Ibanez
- King's College London, Institute of Psychiatry, Psychology and Neuroscience, De Crespigny Park, Denmark Hill, London SE5 8AF, UK
| | - Claudie Hooper
- King's College London, Institute of Psychiatry, Psychology and Neuroscience, De Crespigny Park, Denmark Hill, London SE5 8AF, UK
| | - Keiko Mizuno
- King's College London, Institute of Psychiatry, Psychology and Neuroscience, De Crespigny Park, Denmark Hill, London SE5 8AF, UK
| | - Dafe Uwanogho
- King's College London, Institute of Psychiatry, Psychology and Neuroscience, De Crespigny Park, Denmark Hill, London SE5 8AF, UK
| | - Mirsada Causevic
- King's College London, Institute of Psychiatry, Psychology and Neuroscience, De Crespigny Park, Denmark Hill, London SE5 8AF, UK
| | - Ayodeji Asuni
- King's College London, Institute of Psychiatry, Psychology and Neuroscience, De Crespigny Park, Denmark Hill, London SE5 8AF, UK
| | - Alvina To
- King's College London, Institute of Psychiatry, Psychology and Neuroscience, De Crespigny Park, Denmark Hill, London SE5 8AF, UK
| | - Salvador Soriano
- Department of Anatomy, Loma Linda University School of Medicine, Loma Linda, Evans Hall B08, 24785 Stewart Street, Loma Linda, CA 92354, USA
| | - K Peter Giese
- King's College London, Institute of Psychiatry, Psychology and Neuroscience, De Crespigny Park, Denmark Hill, London SE5 8AF, UK
| | - Simon Lovestone
- University of Oxford, Department of Psychiatry, Warneford Hospital, Oxford OX3 7JX, UK
| | - Richard Killick
- King's College London, Institute of Psychiatry, Psychology and Neuroscience, De Crespigny Park, Denmark Hill, London SE5 8AF, UK.
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Proteolytic control of neurite outgrowth inhibitor NOGO-A by the cAMP/PKA pathway. Proc Natl Acad Sci U S A 2014; 111:15729-34. [PMID: 25331889 DOI: 10.1073/pnas.1410274111] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Protein kinase A (PKA) controls major aspects of neurite outgrowth and morphogenesis and plays an essential role in synaptic plasticity and memory. However, the molecular mechanism(s) of PKA action on neurite sprouting and activity are still unknown. Here, we report that in response to neurotrophin or cAMP stimulation the RING ligase praja2 ubiquitinates and degrades NOGO-A, a major inhibitor of neurite outgrowth in mammalian brain. Genetic silencing of praja2 severely inhibited neurite extension of differentiating neuroblastoma cells and mesencephalic neurons and axon outgrowth and sprouting of striatal terminals in developing rat brain. This phenotype was rescued when both praja2 and NOGO-A were depleted, suggesting that NOGO-A is, indeed, a biologically relevant target of praja2 in neuronal cells. Our findings unveil a novel mechanism that functionally couples cAMP signaling with the proteolytic turnover of NOGO-A, positively impacting on neurite outgrowth in mammalian brain.
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22
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Gadd45b Mediates Axonal Plasticity and Subsequent Functional Recovery After Experimental Stroke in Rats. Mol Neurobiol 2014; 52:1245-1256. [DOI: 10.1007/s12035-014-8909-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 09/28/2014] [Indexed: 01/25/2023]
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Spinal motor neurite outgrowth over glial scar inhibitors is enhanced by coculture with bone marrow stromal cells. Spine J 2014; 14:1722-33. [PMID: 24462452 DOI: 10.1016/j.spinee.2014.01.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 12/17/2013] [Accepted: 01/09/2014] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Transplantation of bone marrow cells into spinal cord lesions promotes functional recovery in animal models, and recent clinical trials suggest possible recovery also in humans. The mechanisms responsible for these improvements are still unclear. PURPOSE To characterize spinal cord motor neurite interactions with human bone marrow stromal cells (MSCs) in an in vitro model of spinal cord injury (SCI). STUDY DESIGN/SETTING Previously, we have reported that human MSCs promote the growth of extending sensory neurites from dorsal root ganglia (DRG), in the presence of some of the molecules present in the glial scar, which are attributed with inhibiting axonal regeneration after SCI. We have adapted and optimized this system replacing the DRG with a spinal cord culture to produce a central nervous system (CNS) model, which is more relevant to the SCI situation. METHODS We have developed and characterized a novel spinal cord culture system. Human MSCs were cocultured with spinal motor neurites in substrate choice assays containing glial scar-associated inhibitors of nerve growth. In separate experiments, MSC-conditioned media were analyzed and added to spinal motor neurites in substrate choice assays. RESULTS As has been reported previously with DRG, substrate-bound neurocan and Nogo-A repelled spinal neuronal adhesion and neurite outgrowth, but these inhibitory effects were abrogated in MSC/spinal cord cocultures. However, unlike DRG, spinal neuronal bodies and neurites showed no inhibition to substrates of myelin-associated glycoprotein. In addition, the MSC secretome contained numerous neurotrophic factors that stimulated spinal neurite outgrowth, but these were not sufficient stimuli to promote spinal neurite extension over inhibitory concentrations of neurocan or Nogo-A. CONCLUSIONS These findings provide novel insight into how MSC transplantation may promote regeneration and functional recovery in animal models of SCI and in the clinic, especially in the chronic situation in which glial scars (and associated neural inhibitors) are well established. In addition, we have confirmed that this CNS model predominantly comprises motor neurons via immunocytochemical characterization. We hope that this model may be used in future research to test various other potential interventions for spinal injury or disease states.
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Harrison BJ, Flight RM, Gomes C, Venkat G, Ellis SR, Sankar U, Twiss JL, Rouchka EC, Petruska JC. IB4-binding sensory neurons in the adult rat express a novel 3' UTR-extended isoform of CaMK4 that is associated with its localization to axons. J Comp Neurol 2014; 522:308-36. [PMID: 23817991 PMCID: PMC3855891 DOI: 10.1002/cne.23398] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 06/13/2013] [Accepted: 06/19/2013] [Indexed: 01/22/2023]
Abstract
Calcium/calmodulin-dependent protein kinase 4 (gene and transcript: CaMK4; protein: CaMKIV) is the nuclear effector of the Ca(2+) /calmodulin kinase (CaMK) pathway where it coordinates transcriptional responses. However, CaMKIV is present in the cytoplasm and axons of subpopulations of neurons, including some sensory neurons of the dorsal root ganglia (DRG), suggesting an extranuclear role for this protein. We observed that CaMKIV was expressed strongly in the cytoplasm and axons of a subpopulation of small-diameter DRG neurons, most likely cutaneous nociceptors by virtue of their binding the isolectin IB4. In IB4+ spinal nerve axons, 20% of CaMKIV was colocalized with the endocytic marker Rab7 in axons that highly expressed CAM-kinase-kinase (CAMKK), an upstream activator of CaMKIV, suggesting a role for CaMKIV in signaling though signaling endosomes. Using fluorescent in situ hybridization (FISH) with riboprobes, we also observed that small-diameter neurons expressed high levels of a novel 3' untranslated region (UTR) variant of CaMK4 mRNA. Using rapid amplification of cDNA ends (RACE), reverse-transcription polymerase chain reaction (RT-PCR) with gene-specific primers, and cDNA sequencing analyses we determined that the novel transcript contains an additional 10 kb beyond the annotated gene terminus to a highly conserved alternate polyadenylation site. Quantitative PCR (qPCR) analyses of fluorescent-activated cell sorted (FACS) DRG neurons confirmed that this 3'-UTR-extended variant was preferentially expressed in IB4-binding neurons. Computational analyses of the 3'-UTR sequence predict that UTR-extension introduces consensus sites for RNA-binding proteins (RBPs) including the embryonic lethal abnormal vision (ELAV)/Hu family proteins. We consider the possible implications of axonal CaMKIV in the context of the unique properties of IB4-binding DRG neurons.
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Affiliation(s)
- Benjamin J. Harrison
- Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky, 40202, USA
- Kentucky Spinal Cord Injury Research Center (KSCIRC), University of Louisville, Louisville, Kentucky, 40292, USA
| | - Robert M. Flight
- Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky, 40202, USA
| | - Cynthia Gomes
- Department of Biochemistry and Molecular Bi ology, University of Louisville School of Medicine, Kentucky, 40202, USA
| | - Gayathri Venkat
- Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky, 40202, USA
- Kentucky Spinal Cord Injury Research Center (KSCIRC), University of Louisville, Louisville, Kentucky, 40292, USA
| | - Steven R Ellis
- Department of Biochemistry and Molecular Bi ology, University of Louisville School of Medicine, Kentucky, 40202, USA
| | - Uma Sankar
- James Graham Brown Cancer Center, University of Louisville, Louisville, Kentucky, 40292, USA
- Owensboro Cancer Research Program, University of Louisville, Owensboro, KY 42303, USA
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky, 40292, USA
| | - Jeffery L. Twiss
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, 19104, USA
| | - Eric C. Rouchka
- Department of Computer Engineering and Computer Science, University of Louisville, Louisville, Kentucky, 40292, USA
| | - Jeffrey C. Petruska
- Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky, 40202, USA
- Kentucky Spinal Cord Injury Research Center (KSCIRC), University of Louisville, Louisville, Kentucky, 40292, USA
- Department of Neurological Surgery, University of Louisville, Louisville, Kentucky, 40202, USA
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25
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Dao AT, Zagaar MA, Levine AT, Salim S, Eriksen JL, Alkadhi KA. Treadmill exercise prevents learning and memory impairment in Alzheimer's disease-like pathology. Curr Alzheimer Res 2014; 10:507-15. [PMID: 23627709 DOI: 10.2174/1567205011310050006] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 01/29/2013] [Accepted: 01/30/2013] [Indexed: 12/29/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder that is characterized by progressive memory loss. In contrast, accumulating evidence suggests a neuroprotective role of regular exercise in aging associated memory impairment. In this study, we investigated the ability of regular exercise to prevent impairments of short-term memory (STM) and early long-term potentiation (E-LTP) in area CA1 of the hippocampus in a rat model of AD (i.c.v. infusion of 250 pmol/day Aβ1-42 peptides). We utilized behavioral assessment, in vivo electrophysiological recording, and immunoblotting in 4 groups of adult Wistar rats: control, treadmill exercise (Ex), β-amyloid-infused (Aβ), and amyloid-infused/treadmill exercised (Ex/Aβ). Our findings indicated that Aβ rats made significantly more errors in the radial arm water maze (RAWM) compared to all other groups and exhibited suppressed E-LTP in area CA1, which correlated with deleterious alterations in the levels of memory and E-LTP-related signaling molecules including calcineurin (PP2B), brain derivedneurotrophic factor (BDNF) and phosphorylated CaMKII (p-CaMKII). Compared to controls, Ex and Ex/Aβ rats showed a similar behavioral performance and a normal E-LTP with no detrimental changes in the levels of PP2B, BDNF, and p- CaMKII. We conclude that treadmill exercise maybe able to prevent cognitive impairment associated with AD pathology.
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Affiliation(s)
- An T Dao
- Department of PPS, College of Pharmacy, University of Houston, Houston, TX 77204-5037, USA
| | - Munder A Zagaar
- Texas Southern University Department of Pharmacy Practice and Clinical Health Sciences Houston, TX 77004
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26
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Carballosa-Gonzalez MM, Vitores A, Hentall ID. Hindbrain raphe stimulation boosts cyclic adenosine monophosphate and signaling proteins in the injured spinal cord. Brain Res 2013; 1543:165-72. [PMID: 24246733 DOI: 10.1016/j.brainres.2013.11.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 11/05/2013] [Accepted: 11/09/2013] [Indexed: 12/20/2022]
Abstract
Early recovery from incomplete spinal cord contusion is improved by prolonged stimulation of the hindbrain's serotonergic nucleus raphe magnus (NRM). Here we examine whether increases in cyclic adenosine monophosphate (cAMP), an intracellular signaling molecule with several known restorative actions on damaged neural tissue, could play a role. Subsequent changes in cAMP-dependent phosphorylation of protein kinase A (PKA) and PKA-dependent phosphorylation of the transcription factor "cAMP response element-binding protein" (CREB) are also analyzed. Rats with moderate weight-drop injury at segment T8 received 2h of NRM stimulation beginning three days after injury, followed immediately by separate extraction of cervical, thoracic and lumbar spinal cord for immunochemical assay. Controls lacked injury, stimulation or both. Injury reduced cAMP levels to under half of normal in all three spinal regions. NRM stimulation completely restored these levels, while producing no significant change in non-injured rats. Pretreatment with the 5-HT7 receptor antagonist pimozide (1 mg/kg, intraperitoneal) lowered cAMP in non-injured rats to injury amounts, which were unchanged by NRM stimulation. The phosphorylated fraction of PKA (pPKA) and CREB (pCREB) was reduced significantly in all three regions after SCI and restored by NRM stimulation, except for pCREB in lumbar segments. In conclusion, SCI produces spreading deficits in cAMP, pPKA and pCREB that are reversible by Gs protein-coupled 5-HT receptors responding to raphe-spinal activity, although these signaling molecules are not reactive to NRM stimulation in normal tissue. These findings can partly explain the benefits of NRM stimulation after SCI.
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Affiliation(s)
| | - Alberto Vitores
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Ian D Hentall
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA.
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27
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Doxycycline-regulated GDNF expression promotes axonal regeneration and functional recovery in transected peripheral nerve. J Control Release 2013; 172:841-51. [PMID: 24140746 DOI: 10.1016/j.jconrel.2013.10.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 09/25/2013] [Accepted: 10/04/2013] [Indexed: 12/27/2022]
Abstract
Increased production of neurotrophic factors (NTFs) is one of the key responses seen following peripheral nerve injury, making them an attractive choice for pro-regenerative gene therapies. However, the downside of over-expression of certain NTFs, including glial cell line-derived neurotrophic factor (GDNF), was earlier found to be the trapping and misdirection of regenerating axons, the so-called 'candy-store' effect. We report a proof-of-principle study on the application of conditional GDNF expression system in injured peripheral nerve. We engineered Schwann cells (SCs) using dendrimers or lentiviral transduction with the vector providing doxycycline-regulated GDNF expression. Injection of GDNF-modified cells into the injured peripheral nerve followed by time-restricted administration of doxycycline demonstrated that GDNF expression in SCs can also be controlled locally in the peripheral nerves of the experimental animals. Cell-based GDNF therapy was shown to increase the extent of axonal regeneration, while controlled deactivation of GDNF effectively prevented trapping of regenerating axons in GDNF-enriched areas, and was associated with improved functional recovery.
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Abstract
While most gene transcription yields RNA transcripts that code for proteins, a sizable proportion of the genome generates RNA transcripts that do not code for proteins, but may have important regulatory functions. The brain-derived neurotrophic factor (BDNF) gene, a key regulator of neuronal activity, is overlapped by a primate-specific, antisense long noncoding RNA (lncRNA) called BDNFOS. We demonstrate reciprocal patterns of BDNF and BDNFOS transcription in highly active regions of human neocortex removed as a treatment for intractable seizures. A genome-wide analysis of activity-dependent coding and noncoding human transcription using a custom lncRNA microarray identified 1288 differentially expressed lncRNAs, of which 26 had expression profiles that matched activity-dependent coding genes and an additional 8 were adjacent to or overlapping with differentially expressed protein-coding genes. The functions of most of these protein-coding partner genes, such as ARC, include long-term potentiation, synaptic activity, and memory. The nuclear lncRNAs NEAT1, MALAT1, and RPPH1, composing an RNAse P-dependent lncRNA-maturation pathway, were also upregulated. As a means to replicate human neuronal activity, repeated depolarization of SY5Y cells resulted in sustained CREB activation and produced an inverse pattern of BDNF-BDNFOS co-expression that was not achieved with a single depolarization. RNAi-mediated knockdown of BDNFOS in human SY5Y cells increased BDNF expression, suggesting that BDNFOS directly downregulates BDNF. Temporal expression patterns of other lncRNA-messenger RNA pairs validated the effect of chronic neuronal activity on the transcriptome and implied various lncRNA regulatory mechanisms. lncRNAs, some of which are unique to primates, thus appear to have potentially important regulatory roles in activity-dependent human brain plasticity.
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29
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Early regenerative effects of NGF-transduced Schwann cells in peripheral nerve repair. Mol Cell Neurosci 2012; 50:103-12. [PMID: 22735691 DOI: 10.1016/j.mcn.2012.04.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 03/27/2012] [Accepted: 04/06/2012] [Indexed: 01/04/2023] Open
Abstract
Peripheral nerve injury leads to a rapid and robust increase in the synthesis of neurotrophins which guide and support regenerating axons. To further optimize neurotrophin supply at the earliest stages of regeneration, we over-expressed NGF in Schwann cells (SCs) by transducing these cells with a lentiviral vector encoding NGF (NGF-SCs). Transplantation of NGF-SCs in a rat sciatic nerve transection/repair model led to significant increase of NGF levels 2weeks after injury and correspondingly to substantial improvement in axonal regeneration. Numbers of NF200, ChAT and CGRP-positive axon profiles, as well as the gastrocnemius muscle weights, were significantly higher in the NGF-Schwann cell group compared to the animals that received control SCs transduced with a lentiviral vector encoding GFP (GFP-SCs). Comparison with other models of NGF application signifies the important role of this neurotrophin during the early stages of regeneration, and supports the importance of developing combined gene and cell therapy for peripheral nerve repair.
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30
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Shakhbazau A, Shcharbin D, Seviaryn I, Goncharova N, Kosmacheva S, Potapnev M, Bryszewska M, Kumar R, Biernaskie J, Midha R. Dendrimer-Driven Neurotrophin Expression Differs in Temporal Patterns between Rodent and Human Stem Cells. Mol Pharm 2012; 9:1521-8. [DOI: 10.1021/mp300041k] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Antos Shakhbazau
- Department
of Clinical Neurosciences,
Faculty of Medicine, University of Calgary, Calgary, Canada
- Hotchkiss
Brain Institute, University of Calgary,
Calgary, Canada
| | - Dzmitry Shcharbin
- Institute
of Biophysics and Cell
Engineering, National Academy of Sciences of Belarus, Minsk, Belarus
| | - Ihar Seviaryn
- Republic Centre for Hematology and Transfusiology, Minsk, Belarus
| | | | | | - Mihail Potapnev
- Republic Centre for Hematology and Transfusiology, Minsk, Belarus
| | - Maria Bryszewska
- Department of General Biophysics, University of Lodz, Lodz, Poland
| | - Ranjan Kumar
- Department
of Clinical Neurosciences,
Faculty of Medicine, University of Calgary, Calgary, Canada
- Hotchkiss
Brain Institute, University of Calgary,
Calgary, Canada
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Canada
| | - Jeffrey Biernaskie
- Hotchkiss
Brain Institute, University of Calgary,
Calgary, Canada
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Canada
| | - Rajiv Midha
- Department
of Clinical Neurosciences,
Faculty of Medicine, University of Calgary, Calgary, Canada
- Hotchkiss
Brain Institute, University of Calgary,
Calgary, Canada
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31
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Moore DL, Goldberg JL. Multiple transcription factor families regulate axon growth and regeneration. Dev Neurobiol 2012; 71:1186-211. [PMID: 21674813 DOI: 10.1002/dneu.20934] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Understanding axon regenerative failure remains a major goal in neuroscience, and reversing this failure remains a major goal for clinical neurology. Although an inhibitory central nervous system environment clearly plays a role, focus on molecular pathways within neurons has begun to yield fruitful insights. Initial steps forward investigated the receptors and signaling pathways immediately downstream of environmental cues, but recent work has also shed light on transcriptional control mechanisms that regulate intrinsic axon growth ability, presumably through whole cassettes of gene target regulation. Here we will discuss transcription factors that regulate neurite growth in vitro and in vivo, including p53, SnoN, E47, cAMP-responsive element binding protein (CREB), signal transducer and activator of transcription 3 (STAT3), nuclear factor of activated T cell (NFAT), c-Jun activating transcription factor 3 (ATF3), sex determining region Ybox containing gene 11 (Sox11), nuclear factor κ-light chain enhancer of activated B cells (NFκB), and Krüppel-like factors (KLFs). Revealing the similarities and differences among the functions of these transcription factors may further our understanding of the mechanisms of transcriptional regulation in axon growth and regeneration.
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Affiliation(s)
- Darcie L Moore
- Bascom Palmer Eye Institute and the Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Florida, USA
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32
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Tedeschi A. Tuning the orchestra: transcriptional pathways controlling axon regeneration. Front Mol Neurosci 2012; 4:60. [PMID: 22294979 PMCID: PMC3257844 DOI: 10.3389/fnmol.2011.00060] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 12/23/2011] [Indexed: 12/13/2022] Open
Abstract
Trauma in the adult mammalian central nervous system leads to irreversible structural and functional impairment due to failed regeneration attempts. In contrast, neurons in the peripheral nervous system exhibit a greater regenerative ability. It has been proposed that an orchestrated sequence of transcriptional events controlling the expression of specific sets of genes may be the underlying basis of an early cell-autonomous regenerative response. Understanding whether transcriptional fine tuning, in parallel with strategies aimed at counteracting extrinsic impediments promotes axon re-growth following central nervous system injuries represents an exciting challenge for future studies. Transcriptional pathways controlling axon regeneration are presented and discussed in this review.
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Affiliation(s)
- Andrea Tedeschi
- Department of Neurology, F. M. Kirby Neurobiology Center, Children's Hospital Boston Boston, MA, USA
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Bidirectional remodeling of β1-integrin adhesions during chemotropic regulation of nerve growth. BMC Biol 2011; 9:82. [PMID: 22126462 PMCID: PMC3283487 DOI: 10.1186/1741-7007-9-82] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 11/30/2011] [Indexed: 12/13/2022] Open
Abstract
Background Chemotropic factors in the extracellular microenvironment guide nerve growth by acting on the growth cone located at the tip of extending axons. Growth cone extension requires the coordination of cytoskeleton-dependent membrane protrusion and dynamic adhesion to the extracellular matrix, yet how chemotropic factors regulate these events remains an outstanding question. We demonstrated previously that the inhibitory factor myelin-associated glycoprotein (MAG) triggers endocytic removal of the adhesion receptor β1-integrin from the growth cone surface membrane to negatively remodel substrate adhesions during chemorepulsion. Here, we tested how a neurotrophin might affect integrin adhesions. Results We report that brain-derived neurotropic factor (BDNF) positively regulates the formation of substrate adhesions in axonal growth cones during stimulated outgrowth and prevents removal of β1-integrin adhesions by MAG. Treatment of Xenopus spinal neurons with BDNF rapidly triggered β1-integrin clustering and induced the dynamic formation of nascent vinculin-containing adhesion complexes in the growth cone periphery. Both the formation of nascent β1-integrin adhesions and the stimulation of axon extension by BDNF required cytoplasmic calcium ion signaling and integrin activation at the cell surface. Exposure to MAG decreased the number of β1-integrin adhesions in the growth cone during inhibition of axon extension. In contrast, the BDNF-induced adhesions were resistant to negative remodeling by MAG, correlating with the ability of BDNF pretreatment to counteract MAG-inhibition of axon extension. Pre-exposure to MAG prevented the BDNF-induced formation of β1-integrin adhesions and blocked the stimulation of axon extension by BDNF. Conclusions Altogether, these findings demonstrate the neurotrophin-dependent formation of integrin-based adhesions in the growth cone and reveal how a positive regulator of substrate adhesions can block the negative remodeling and growth inhibitory effects of MAG. Such bidirectional remodeling may allow the growth cone to rapidly adjust adhesiveness to the extracellular matrix as a general mechanism for governing axon extension. Techniques for manipulating integrin internalization and activation state may be important for overcoming local inhibitory factors after traumatic injury or neurodegenerative disease to enhance regenerative nerve growth.
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BDNF-promoted increases in proximal dendrites occur via CREB-dependent transcriptional regulation of cypin. J Neurosci 2011; 31:9735-45. [PMID: 21715638 DOI: 10.1523/jneurosci.6785-10.2011] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Alterations in dendrite branching and morphology are present in many neurodegenerative diseases. These variations disrupt postsynaptic transmission and affect neuronal communication. Thus, it is important to understand the molecular mechanisms that regulate dendritogenesis and how they go awry during disease states. Previously, our laboratory showed that cypin, a mammalian guanine deaminase, increases dendrite number when overexpressed and decreases dendrite number when knocked down in cultured hippocampal neurons. Here, we report that exposure to brain-derived neurotrophic factor (BDNF), an important mediator of dendrite arborization, for 72 h but not for 24 h or less increases cypin mRNA and protein levels in rat hippocampal neurons. BDNF signals through cypin to regulate dendrite number, since knocking down cypin blocks the effects of BDNF. Furthermore, BDNF increases cypin levels via mitogen-activated protein kinase and transcription-dependent signaling pathways. Moreover, the cypin promoter region contains putative conserved cAMP response element (CRE) regions, which we found can be recognized and activated by CRE-binding protein (CREB). In addition, exposure of the neurons to BDNF increased CREB binding to the cypin promoter and, in line with these data, expression of a dominant negative form of CREB blocked BDNF-promoted increases in cypin protein levels and proximal dendrite branches. Together, these studies suggest that BDNF increases neuronal cypin expression by the activation of CREB, increasing cypin transcription leading to increased protein expression, thus identifying a novel pathway by which BDNF shapes the dendrite network.
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35
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Budni J, Romero A, Molz S, Martín-de-Saavedra M, Egea J, Del Barrio L, Tasca C, Rodrigues A, López M. Neurotoxicity induced by dexamethasone in the human neuroblastoma SH-SY5Y cell line can be prevented by folic acid. Neuroscience 2011; 190:346-53. [DOI: 10.1016/j.neuroscience.2011.05.053] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2011] [Revised: 05/19/2011] [Accepted: 05/22/2011] [Indexed: 01/21/2023]
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Wang Y, Yang F, Fu Y, Huang X, Wang W, Jiang X, Gritsenko MA, Zhao R, Monore ME, Pertz OC, Purvine SO, Orton DJ, Jacobs JM, Camp DG, Smith RD, Klemke RL. Spatial phosphoprotein profiling reveals a compartmentalized extracellular signal-regulated kinase switch governing neurite growth and retraction. J Biol Chem 2011; 286:18190-201. [PMID: 21454597 DOI: 10.1074/jbc.m111.236133] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Brain development and spinal cord regeneration require neurite sprouting and growth cone navigation in response to extension and collapsing factors present in the extracellular environment. These external guidance cues control neurite growth cone extension and retraction processes through intracellular protein phosphorylation of numerous cytoskeletal, adhesion, and polarity complex signaling proteins. However, the complex kinase/substrate signaling networks that mediate neuritogenesis have not been investigated. Here, we compare the neurite phosphoproteome under growth and retraction conditions using neurite purification methodology combined with mass spectrometry. More than 4000 non-redundant phosphorylation sites from 1883 proteins have been annotated and mapped to signaling pathways that control kinase/phosphatase networks, cytoskeleton remodeling, and axon/dendrite specification. Comprehensive informatics and functional studies revealed a compartmentalized ERK activation/deactivation cytoskeletal switch that governs neurite growth and retraction, respectively. Our findings provide the first system-wide analysis of the phosphoprotein signaling networks that enable neurite growth and retraction and reveal an important molecular switch that governs neuritogenesis.
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Affiliation(s)
- Yingchun Wang
- Department of Pathology and Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
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Fouad K, Tetzlaff W. Rehabilitative training and plasticity following spinal cord injury. Exp Neurol 2011; 235:91-9. [PMID: 21333646 DOI: 10.1016/j.expneurol.2011.02.009] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2010] [Revised: 02/04/2011] [Accepted: 02/10/2011] [Indexed: 12/15/2022]
Abstract
Rehabilitative training is currently one of the most successful treatments to promote functional recovery following spinal cord injury. Nevertheless, there are many unanswered questions including the most effective and beneficial design, and the mechanisms underlying the training effects on motor recovery. Furthermore, rehabilitative training will certainly be combined with pharmacological treatments developed to promote the "repair" of the injured spinal cord. Thus, insight into training-induced mechanisms will be of great importance to fine tune such combined treatments. In this review we address current challenges of rehabilitative training and mechanisms involved in promoting motor recovery with the focus on animal models. These challenges suggest that although rehabilitative training appears to be a relatively straight forward treatment approach, more research is needed to optimize its effect on functional outcome in order to enhance our chances of success when combining pharmacological treatments promoting axonal growth and rehabilitative training in the clinic.
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Affiliation(s)
- K Fouad
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Canada.
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Sánchez-Muñoz I, Sánchez-Franco F, Vallejo M, Fernández A, Palacios N, Fernández M, Sánchez-Grande M, Cacicedo L. Regulation of somatostatin gene expression by brain derived neurotrophic factor in fetal rat cerebrocortical cells. Brain Res 2011; 1375:28-40. [DOI: 10.1016/j.brainres.2010.12.031] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 12/09/2010] [Accepted: 12/10/2010] [Indexed: 10/18/2022]
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Mellough CB, Cho S, Wood A, Przyborski S. Neurite formation by neurons derived from adult rat hippocampal progenitor cells is susceptible to myelin inhibition. Neurochem Int 2011; 59:333-40. [DOI: 10.1016/j.neuint.2011.01.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 01/04/2011] [Accepted: 01/12/2011] [Indexed: 12/09/2022]
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Liu Y, Gong Z, Liu L, Sun H. Combined effect of olfactory ensheathing cell (OEC) transplantation and glial cell line-derived neurotrophic factor (GDNF) intravitreal injection on optic nerve injury in rats. Mol Vis 2010; 16:2903-10. [PMID: 21203408 PMCID: PMC3013062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Accepted: 12/25/2010] [Indexed: 11/01/2022] Open
Abstract
PURPOSE To investigate the combined effect of olfactory ensheathing cell (OEC) transplantation and recombinant human glial cell line-derived neurotrophic factor (rhGDNF) intravitreal injection on optic nerve functional recovery following incomplete injury in adult rats. METHODS The optic nerves of adult rats were crushed by forceps and then GDNF was injected into vitreous cavity, OECs transplanted into injured optic nerve, or GDNF vitreous injection combined with OECs transplantation, and balanced salt solution was injected into vitreous cavity of control group rats respectively. Flash visual evoked potential (F-VEP) was performed on the injured eye immediately after injury and at 1, 2, 4, and 8 weeks after injury. RESULTS The F-VEP waveforms were almost silent immediately after the optic nerve injury. The latency of the F-VEP (LP1) recovered nearly to the normal value 1 week after injury in the treatment groups. The amplitude recovered more slowly. It recovered more obviously and rapidly in the rhGDNF combined with OEC group. At 8 weeks after injury, the amplitude was restored to 64.5% of the pre-injury level in the control group and to 91.8% in the GDNF+OEC treatment group. Wheat germ agglutinin (WGA) labeling showed retinal ganglion cell (RGC) axon regeneration and prolongation in the combined group, and the regenerated axons extended across the traumatized area and reached the distal end of the injured optic nerve. CONCLUSIONS The combination of OEC transplantation and rhGDNF intravitreal injection will be more effective in promoting the recovery of visual function after incomplete injury of the optic nerve in adult rats.
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Affiliation(s)
- Yong Liu
- Department of Neurology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Zili Gong
- Department of Neurology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Lan Liu
- Department of Ophthalmology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Hanjun Sun
- Department of Ophthalmology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
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Kusik BW, Hammond DR, Udvadia AJ. Transcriptional regulatory regions of gap43 needed in developing and regenerating retinal ganglion cells. Dev Dyn 2010; 239:482-95. [PMID: 20034105 DOI: 10.1002/dvdy.22190] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Mammals and fish differ in their ability to express axon growth-associated genes in response to CNS injury, which contributes to the differences in their ability for CNS regeneration. Previously we demonstrated that for the axon growth-associated gene, gap43, regions of the rat promoter that are sufficient to promote reporter gene expression in the developing zebrafish nervous system are not sufficient to promote expression in regenerating retinal ganglion cells in zebrafish. Recently, we identified a 3.6-kb gap43 promoter fragment from the pufferfish, Takifugu rubripes (fugu), that can promote reporter gene expression during both development and regeneration. Using promoter deletion analysis, we have found regions of the 3.6-kb fugu gap43 promoter that are necessary for expression in regenerating, but not developing, retinal ganglion cells. Within the 3.6-kb promoter, we have identified elements that are highly conserved among fish, as well as elements conserved among fish, mammals, and birds.
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Affiliation(s)
- Brandon W Kusik
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
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Hu Y, Cho S, Goldberg JL. Neurotrophic effect of a novel TrkB agonist on retinal ganglion cells. Invest Ophthalmol Vis Sci 2009; 51:1747-54. [PMID: 19875669 DOI: 10.1167/iovs.09-4450] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
PURPOSE Retinal ganglion cells (RGCs) die in glaucoma and virtually all optic neuropathies. Recently, novel tropomyosin-related kinase B (TrkB) monoclonal antibodies have been shown to activate TrkB receptors and exert neuroprotective and neurotrophic effects. In the present study, the authors examined the ability of one of them, 29D7, to elicit RGC survival and neurite growth both in culture and in vivo. METHODS RGCs from postnatal day (P)3 to P4 Sprague-Dawley rats were isolated by sequential immunopanning using a monoclonal antibody to Thy1. RGCs were cultured in serum-free defined medium in 96-well plates. RGC viability was assessed after 1 to 3 days by MTT assay. Activation of TrkB and downstream signaling molecules was confirmed by Western blot analysis. Intravitreal injections of 29D7 were performed after optic nerve axotomy, and subsequent RGC survival was quantified using beta-III tubulin immunostaining. Regeneration was assessed using retrograde fluorogold tracing in an optic nerve-peripheral nerve graft model. RESULTS Similar to brain-derived neurotrophic factor (BDNF), the 29D7 antibody strongly promoted RGC survival and neurite growth in vitro compared with medium alone or control IgG. Forskolin, which weakly supported RGC survival on its own, potentiated the effect of 29D7. Intravitreal injection of 29D7 enhanced RGC survival but not regeneration in vivo 2 weeks after optic nerve injury. CONCLUSIONS Together, these findings demonstrate the potential for antibody-mediated TrkB agonism as a potential therapeutic approach to enhance RGC survival after optic nerve injury. Further studies are needed to elucidate the mechanistic differences between this TrkB agonist and BDNF.
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Affiliation(s)
- Ying Hu
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
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Takemura M, Mishima T, Wang Y, Kasahara J, Fukunaga K, Ohashi K, Mizuno K. Ca2+/calmodulin-dependent protein kinase IV-mediated LIM kinase activation is critical for calcium signal-induced neurite outgrowth. J Biol Chem 2009; 284:28554-62. [PMID: 19696021 DOI: 10.1074/jbc.m109.006296] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Actin cytoskeletal remodeling is essential for neurite outgrowth. LIM kinase 1 (LIMK1) regulates actin cytoskeletal remodeling by phosphorylating and inactivating cofilin, an actin filament-disassembling factor. In this study, we investigated the role of LIMK1 in calcium signal-induced neurite outgrowth. The calcium ionophore ionomycin induced LIMK1 activation and cofilin phosphorylation in Neuro-2a neuroblastoma cells. Knockdown of LIMK1 or expression of a kinase-dead mutant of LIMK1 suppressed ionomycin-induced cofilin phosphorylation and neurite outgrowth in Neuro-2a cells. Ionomycin-induced cofilin phosphorylation and neurite outgrowth were also blocked by KN-93, an inhibitor of Ca(2+)/calmodulin-dependent protein kinases (CaMKs), and STO-609, an inhibitor of CaMK kinase. An active form of CaMKIV but not CaMKI enhanced Thr-508 phosphorylation of LIMK1 and increased the kinase activity of LIMK1. Moreover, the active form of CaMKIV induced cofilin phosphorylation and neurite outgrowth, and a dominant negative form of CaMKIV suppressed ionomycin-induced neurite outgrowth. Taken together, our results suggest that LIMK1-mediated cofilin phosphorylation is critical for ionomycin-induced neurite outgrowth and that CaMKIV mediates ionomycin-induced LIMK1 activation.
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Affiliation(s)
- Miyohiko Takemura
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
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Murray AJ, Peace AG, Shewan DA. cGMP promotes neurite outgrowth and growth cone turning and improves axon regeneration on spinal cord tissue in combination with cAMP. Brain Res 2009; 1294:12-21. [PMID: 19646425 DOI: 10.1016/j.brainres.2009.07.071] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2009] [Revised: 07/13/2009] [Accepted: 07/21/2009] [Indexed: 01/20/2023]
Abstract
Cyclic adenosine monophosphate (cAMP) has been intensively studied in recent years in order to elucidate its contribution in intracellular signalling mechanisms that regulate axon growth and guidance, and also to test if its activation can promote axon regeneration after injury. Cyclic guanosine monophosphate (cGMP), however, has been given considerably less attention even though it too mediates intracellular signalling cascades activated by extracellular guidance cues. cGMP can promote neurite outgrowth in neuronal cell lines but its role in promoting growth and regeneration of primary neurons is not well established. Here, we have examined the effects of elevating cGMP activity on axon growth, guidance and regeneration in vitro. We have found that, like cAMP elevation, activation of cGMP increases rat dorsal root ganglion (DRG) neurite outgrowth on a polylysine substrate and that asymmetric cGMP elevation promotes attractive growth cone turning. When grown in an in vitro model of axon regeneration activation of cGMP alone was not sufficient to promote adult neurite outgrowth. However, when combined with cAMP elevation substantial regeneration of adult neurites is achieved, superior to that achieved with either cAMP or cGMP alone. Regeneration is enhanced still further with simultaneous application of a Nogo receptor blocking peptide, suggesting this combinatorial strategy could achieve far greater axon regeneration in vivo than targeting individual cell signalling mechanisms.
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Affiliation(s)
- Andrew J Murray
- School of Medical Sciences, College of Life Sciences and Medicine, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK.
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Gokce O, Runne H, Kuhn A, Luthi-Carter R. Short-term striatal gene expression responses to brain-derived neurotrophic factor are dependent on MEK and ERK activation. PLoS One 2009; 4:e5292. [PMID: 19390590 PMCID: PMC2669182 DOI: 10.1371/journal.pone.0005292] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Accepted: 03/26/2009] [Indexed: 12/25/2022] Open
Abstract
Background Brain-derived neurotrophic factor (BDNF) is believed to be an important regulator of striatal neuron survival, differentiation, and plasticity. Moreover, reduction of BDNF delivery to the striatum has been implicated in the pathophysiology of Huntington's disease. Nevertheless, many essential aspects of BDNF responses in striatal neurons remain to be elucidated. Methodology/Principal Findings In this study, we assessed the relative contributions of multipartite intracellular signaling pathways to the short-term induction of striatal gene expression by BDNF. To identify genes regulated by BDNF in these GABAergic cells, we first used DNA microarrays to quantify their transcriptomic responses following 3 h of BDNF exposure. The signal transduction pathways underlying gene induction were subsequently dissected using pharmacological agents and quantitative real-time PCR. Gene expression responses to BDNF were abolished by inhibitors of TrkB (K252a) and calcium (chelator BAPTA-AM and transient receptor potential cation channel [TRPC] antagonist SKF-96365). Interestingly, inhibitors of mitogen-activated protein kinase kinases 1 and 2 (MEK1/2) and extracellular signal-regulated kinase ERK also blocked the BDNF-mediated induction of all tested BDNF-responsive genes. In contrast, inhibitors of nitric oxide synthase (NOS), phosphotidylinositol-3-kinase (PI3K), and CAMK exhibited less prevalent, gene-specific effects on BDNF-induced RNA expression. At the nuclear level, the activation of both Elk-1 and CREB showed MEK dependence. Importantly, MEK-dependent activation of transcription was shown to be required for BDNF-induced striatal neurite outgrowth, providing evidence for its contribution to striatal neuron plasticity. Conclusions These results show that the MEK/ERK pathway is a major mediator of neuronal plasticity and other important BDNF-dependent striatal functions that are fulfilled through the positive regulation of gene expression.
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Affiliation(s)
- Ozgun Gokce
- Laboratory of Functional Neurogenomics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Heike Runne
- Laboratory of Functional Neurogenomics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Alexandre Kuhn
- Laboratory of Functional Neurogenomics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Ruth Luthi-Carter
- Laboratory of Functional Neurogenomics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- * E-mail:
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Abstract
Homeostatic synaptic scaling is a form of synaptic plasticity that adjusts the strength of all of a neuron's excitatory synapses up or down to stabilize firing. Current evidence suggests that neurons detect changes in their own firing rates through a set of calcium-dependent sensors that then regulate receptor trafficking to increase or decrease the accumulation of glutamate receptors at synaptic sites. Additional mechanisms may allow local or network-wide changes in activity to be sensed through parallel pathways, generating a nested set of homeostatic mechanisms that operate over different temporal and spatial scales.
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Epac mediates cyclic AMP-dependent axon growth, guidance and regeneration. Mol Cell Neurosci 2008; 38:578-88. [PMID: 18583150 DOI: 10.1016/j.mcn.2008.05.006] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2008] [Revised: 04/27/2008] [Accepted: 05/07/2008] [Indexed: 01/31/2023] Open
Abstract
A decline in developing neuronal cAMP levels appears to render mammalian axons susceptible to growth inhibitory factors in the damaged CNS. cAMP elevation enhances axon regeneration, but the cellular mechanisms involved have yet to be fully elucidated. Epac has been identified as a signaling protein that can be activated by cAMP independently of PKA, but little is known of its expression or role in the nervous system. We report that Epac expression is developmentally regulated in the rat nervous system, and that activation of Epac promotes DRG neurite outgrowth and is as effective as cAMP elevation in promoting neurite regeneration on spinal cord tissue. Additionally, siRNA mediated knockdown of Epac reduces DRG neurite outgrowth, prevents the increased growth promoted by cAMP elevation and also diminishes the ability of embryonic neurons to grow processes on spinal cord tissue. Furthermore, we show that asymmetric activation of Epac promotes attractive growth cone turning in a similar manner to cAMP activation. We propose that Epac plays a role in mediating cAMP-dependent axon growth and guidance, and may provide an important target for inducing axon regeneration in vivo.
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