1
|
Hausott B, Glueckert R, Schrott-Fischer A, Klimaschewski L. Signal Transduction Regulators in Axonal Regeneration. Cells 2022; 11:cells11091537. [PMID: 35563843 PMCID: PMC9104247 DOI: 10.3390/cells11091537] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/27/2022] [Accepted: 04/28/2022] [Indexed: 11/16/2022] Open
Abstract
Intracellular signal transduction in response to growth factor receptor activation is a fundamental process during the regeneration of the nervous system. In this context, intracellular inhibitors of neuronal growth factor signaling have become of great interest in the recent years. Among them are the prominent signal transduction regulators Sprouty (SPRY) and phosphatase and tensin homolog deleted on chromosome 10 (PTEN), which interfere with major signaling pathways such as extracellular signal-regulated kinase (ERK) or phosphoinositide 3-kinase (PI3K)/Akt in neurons and glial cells. Furthermore, SPRY and PTEN are themselves tightly regulated by ubiquitin ligases such as c-casitas b-lineage lymphoma (c-CBL) or neural precursor cell expressed developmentally down-regulated protein 4 (NEDD4) and by different microRNAs (miRs) including miR-21 and miR-222. SPRY, PTEN and their intracellular regulators play an important role in the developing and the lesioned adult central and peripheral nervous system. This review will focus on the effects of SPRY and PTEN as well as their regulators in various experimental models of axonal regeneration in vitro and in vivo. Targeting these signal transduction regulators in the nervous system holds great promise for the treatment of neurological injuries in the future.
Collapse
Affiliation(s)
- Barbara Hausott
- Institute of Neuroanatomy, Medical University Innsbruck, 6020 Innsbruck, Austria;
- Correspondence:
| | - Rudolf Glueckert
- Department of Otorhinolaryngology, Medical University Innsbruck, 6020 Innsbruck, Austria; (R.G.); (A.S.-F.)
| | - Anneliese Schrott-Fischer
- Department of Otorhinolaryngology, Medical University Innsbruck, 6020 Innsbruck, Austria; (R.G.); (A.S.-F.)
| | - Lars Klimaschewski
- Institute of Neuroanatomy, Medical University Innsbruck, 6020 Innsbruck, Austria;
| |
Collapse
|
2
|
Shen H, Wang J, Shen L, Wang H, Li W, Ding X. Phosphatase and tensin homolog deletion enhances neurite outgrowth during neural stem cell differentiation. Neuropathology 2020; 40:224-231. [PMID: 32037610 DOI: 10.1111/neup.12633] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 10/18/2019] [Accepted: 11/20/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Huachao Shen
- Department of Neurology, BenQ Medical CenterThe Affiliated BenQ Hospital of Nanjing Medical University Nanjing China
- BenQ Neurological Institute of Nanjing Medical University Nanjing China
| | - Jie Wang
- Department of NeurologyThe Affiliated Jiangning Hospital of Nanjing Medical University Nanjing China
| | - Lihua Shen
- Department of NeurologyThe Affiliated Hospital of Nantong University Nantong China
| | - Huamei Wang
- Department of NeurologyThe Affiliated Jiangning Hospital of Nanjing Medical University Nanjing China
| | - Wenlei Li
- Department of NeurologyJiangsu Provincial Hospital of Chinese Medicine Affiliated to Nanjing University of Traditional Chinese Medicine Nanjing China
| | - Xinsheng Ding
- Department of NeurologyThe Affiliated Sir Run Run Hospital and First Affiliated Hospital of Nanjing Medical University Nanjing China
| |
Collapse
|
3
|
Di Donato M, Cernera G, Migliaccio A, Castoria G. Nerve Growth Factor Induces Proliferation and Aggressiveness In Prostate Cancer Cells. Cancers (Basel) 2019; 11:E784. [PMID: 31174415 PMCID: PMC6627659 DOI: 10.3390/cancers11060784] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 06/05/2019] [Accepted: 06/06/2019] [Indexed: 12/20/2022] Open
Abstract
Resistance to hormone therapy and disease progression is the major challenge in clinical management of prostate cancer (PC). Drugs currently used in PC therapy initially show a potent antitumor effects, but PC gradually develops resistance, relapses and spreads. Most patients who fail primary therapy and have recurrences eventually develop castration-resistant prostate cancer (CRPC), which is almost incurable. The nerve growth factor (NGF) acts on a variety of non-neuronal cells by activating the NGF tyrosine-kinase receptor, tropomyosin receptor kinase A (TrkA). NGF signaling is deregulated in PC. In androgen-dependent PC cells, TrkA mediates the proliferative action of NGF through its crosstalk with the androgen receptor (AR). Epithelial PC cells, however, acquire the ability to express NGF and TrkA, as the disease progresses, indicating a role for NGF/TrkA axis in PC progression and androgen-resistance. We here report that once activated by NGF, TrkA mediates proliferation, invasiveness and epithelial-mesenchymal transition (EMT) in various CRPC cells. NGF promotes organoid growth in 3D models of CRPC cells, and specific inhibition of TrkA impairs all these responses. Thus TrkA represents a new biomarker to target in CRPC.
Collapse
Affiliation(s)
- Marzia Di Donato
- Department of Precision Medicine-University of Campania 'L. Vanvitelli'-via L. De Crecchio, 7-80138 Naples, Italy.
| | - Gustavo Cernera
- Department of Precision Medicine-University of Campania 'L. Vanvitelli'-via L. De Crecchio, 7-80138 Naples, Italy.
| | - Antimo Migliaccio
- Department of Precision Medicine-University of Campania 'L. Vanvitelli'-via L. De Crecchio, 7-80138 Naples, Italy.
| | - Gabriella Castoria
- Department of Precision Medicine-University of Campania 'L. Vanvitelli'-via L. De Crecchio, 7-80138 Naples, Italy.
| |
Collapse
|
4
|
Duraikannu A, Krishnan A, Chandrasekhar A, Zochodne DW. Beyond Trophic Factors: Exploiting the Intrinsic Regenerative Properties of Adult Neurons. Front Cell Neurosci 2019; 13:128. [PMID: 31024258 PMCID: PMC6460947 DOI: 10.3389/fncel.2019.00128] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 03/14/2019] [Indexed: 01/19/2023] Open
Abstract
Injuries and diseases of the peripheral nervous system (PNS) are common but frequently irreversible. It is often but mistakenly assumed that peripheral neuron regeneration is robust without a need to be improved or supported. However, axonal lesions, especially those involving proximal nerves rarely recover fully and injuries generally are complicated by slow and incomplete regeneration. Strategies to enhance the intrinsic growth properties of reluctant adult neurons offer an alternative approach to consider during regeneration. Since axons rarely regrow without an intimately partnered Schwann cell (SC), approaches to enhance SC plasticity carry along benefits to their axon partners. Direct targeting of molecules that inhibit growth cone plasticity can inform important regenerative strategies. A newer approach, a focus of our laboratory, exploits tumor suppressor molecules that normally dampen unconstrained growth. However several are also prominently expressed in stable adult neurons. During regeneration their ongoing expression “brakes” growth, whereas their inhibition and knockdown may enhance regrowth. Examples have included phosphatase and tensin homolog deleted on chromosome ten (PTEN), a tumor suppressor that inhibits PI3K/pAkt signaling, Rb1, the protein involved in retinoblastoma development, and adenomatous polyposis coli (APC), a tumor suppressor that inhibits β-Catenin transcriptional signaling and its translocation to the nucleus. The identification of several new targets to manipulate the plasticity of regenerating adult peripheral neurons is exciting. How they fit with canonical regeneration strategies and their feasibility require additional work. Newer forms of nonviral siRNA delivery may be approaches for molecular manipulation to improve regeneration.
Collapse
Affiliation(s)
- Arul Duraikannu
- Division of Neurology, Department of Medicine, and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Anand Krishnan
- Division of Neurology, Department of Medicine, and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Ambika Chandrasekhar
- Division of Neurology, Department of Medicine, and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Douglas W Zochodne
- Division of Neurology, Department of Medicine, and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| |
Collapse
|
5
|
Sander C, Wallenborn M, Brandt VP, Ahnert P, Reuschel V, Eisenlöffel C, Krupp W, Meixensberger J, Holland H. Central neurocytoma: SNP array analyses, subtel FISH, and review of the literature. Pathol Res Pract 2019; 215:152397. [PMID: 31000381 DOI: 10.1016/j.prp.2019.03.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 03/14/2019] [Accepted: 03/26/2019] [Indexed: 12/29/2022]
Abstract
The central neurocytoma (CN) is a rare brain tumor with a frequency of 0.1-0.5% of all brain tumors. According to the World Health Organization classification, it is a benign grade II tumor with good prognosis. However, some CN occur as histologically "atypical" variant, combined with increasing proliferation and poor clinical outcome. Detailed genetic knowledge could be helpful to characterize a potential atypical behavior in CN. Only few publications on genetics of CN exist in the literature. Therefore, we performed cytogenetic analysis of an intraventricular neurocytoma WHO grade II in a 39-year-old male patient by use of genome-wide high-density single nucleotide polymorphism array (SNP array) and subtelomere FISH. Applying these techniques, we could detect known chromosomal aberrations and identified six not previously described chromosomal aberrations, gains of 1p36.33-p36.31, 2q37.1-q37.3, 6q27, 12p13.33-p13.31, 20q13.31-q13.33, and loss of 19p13.3-p12. Our case report contributes to the genetic knowledge about CN and to increased understanding of "typical" and "atypical" variants.
Collapse
Affiliation(s)
- Caroline Sander
- Dept. of Neurosurgery, University of Leipzig, Liebigstraße 26, 04103 Leipzig, Germany.
| | - Marco Wallenborn
- Dept. of Neurosurgery, University of Leipzig, Liebigstraße 26, 04103 Leipzig, Germany; Saxonian Incubator for Clinical Translation, University of Leipzig, Philipp-Rosenthal Str. 55, 04103 Leipzig, Germany.
| | - Vivian Pascal Brandt
- Saxonian Incubator for Clinical Translation, University of Leipzig, Philipp-Rosenthal Str. 55, 04103 Leipzig, Germany.
| | - Peter Ahnert
- Institute for Medical Informatics, Statistics and Epidemiology, University of Leipzig, Haertelstraße 16-18, 04107 Leipzig, Germany.
| | - Vera Reuschel
- Dept. of Neuroradiology, University of Leipzig, Liebigstraße 22a, 04103 Leipzig, Germany
| | - Christan Eisenlöffel
- Dept. of Neuropathology, University of Leipzig, Liebigstraße 26, 04103 Leipzig, Germany
| | - Wolfgang Krupp
- Dept. of Neurosurgery, University of Leipzig, Liebigstraße 26, 04103 Leipzig, Germany.
| | - Jürgen Meixensberger
- Dept. of Neurosurgery, University of Leipzig, Liebigstraße 26, 04103 Leipzig, Germany.
| | - Heidrun Holland
- Saxonian Incubator for Clinical Translation, University of Leipzig, Philipp-Rosenthal Str. 55, 04103 Leipzig, Germany.
| |
Collapse
|
6
|
Dong ZY, Pei Z, Wang YL, Li Z, Khan A, Meng XT. Ascl1 Regulates Electric Field-Induced Neuronal Differentiation Through PI3K/Akt Pathway. Neuroscience 2019; 404:141-152. [PMID: 30771509 DOI: 10.1016/j.neuroscience.2019.02.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 01/31/2019] [Accepted: 02/04/2019] [Indexed: 12/14/2022]
Abstract
Directing differentiation of neural stem/progenitor cells (NSCs/NPCs) to produce functional neurons is one of the greatest challenges in regenerative medicine. Our previous paper has confirmed that electrical stimulation has a high efficiency of triggering neuronal differentiation by using isolated filum terminale (FT)-derived NPCs. To further clarify the intrinsic molecular mechanisms, protein-protein interaction (PPI) network analysis was applied to pinpoints novel hubs in electric field (EF)-induced neuronal differentiation. In this study, siRNA transfection of Achaete-scute homolog 1 (Ascl1) in NPCs or NPCs was followed by direct current stimulation at 150 mV/mm. Neuronal differentiation rate and protein expression level were analyzed after 7 or 14 days of electrical stimulation. The data showed that the expression level of Ascl1 was enhanced by electrical stimulation and positively correlated to EF strength. Moreover, we identified that the expression of Ascl1 positively regulated neuronal differentiation of NPCs and can be up-regulated by EF-stimulation through the activation of phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) pathway. Therefore, this study provides new insights into the role of Ascl1 and its relevant PI3K/Akt pathway in regulating of EF-induced neuronal differentiation and pointed out that continuous expression of Ascl1 in NPCs is required for EF-induced neuronal differentiation.
Collapse
Affiliation(s)
- Zhi-Yong Dong
- Department of Histology & Embryology, College of Basic Medical Sciences, Jilin University, Changchun 130021, PR China.
| | - Zhe Pei
- Department of Neuroscience and Pediatric, GSRB1 Duke University, Durham 27710, USA
| | - Yan-Ling Wang
- Laboratory Teaching Center of Basic Medicine, College of Basic Medical Sciences, Jilin University, Changchun 130021, PR China.
| | - Zhe Li
- Laboratory Teaching Center of Basic Medicine, College of Basic Medical Sciences, Jilin University, Changchun 130021, PR China.
| | - Amber Khan
- The Graduate Center and CUNY School of Medicine, CUNY, 85 St Nicholas Terrace, New York, NY 10027, USA.
| | - Xiao-Ting Meng
- Department of Histology & Embryology, College of Basic Medical Sciences, Jilin University, Changchun 130021, PR China.
| |
Collapse
|
7
|
Song Z, Han X, Zou H, Zhang B, Ding Y, Xu X, Zeng J, Liu J, Gong A. PTEN-GSK3β-MOB1 axis controls neurite outgrowth in vitro and in vivo. Cell Mol Life Sci 2018; 75:4445-4464. [PMID: 30069702 PMCID: PMC11105474 DOI: 10.1007/s00018-018-2890-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 07/23/2018] [Accepted: 07/25/2018] [Indexed: 12/14/2022]
Abstract
Mps One binder 1 (MOB1) is a core component of NDR/LATS kinase and a positive regulator of the Hippo signaling pathway. However, its role in neurite outgrowth still remains to be clarified. Here, we confirmed, for the first time, that MOB1 promoted neurite outgrowth and was involved in functional recovery after spinal cord injury (SCI) in mice. Mechanistically, we found that MOB1 stability was regulated by the PTEN-GSK3β axis. The MOB1 protein was significantly up-regulated in PTEN-knockdown neuronal cells. This effect was dependent on the lipid phosphatase activity of PTEN. Moreover, MOB1 was found to be a novel substrate for GSK3β that is phosphorylated on serine 146 and degraded via the ubiquitin-proteasome system (UPS). Finally, in vivo lentiviral-mediated silencing of PTEN promoted neurite outgrowth and functional recovery after SCI and this effect was reversed by down-regulation of MOB1. Taken together, this study provided mechanistic insight into how MOB1 acts as a novel and a necessary regulator in PTEN-GSK3β axis that controls neurite outgrowth after SCI.
Collapse
Affiliation(s)
- Zhiwen Song
- Department of Orthopaedics, School of Medicine, The Third Affiliated Hospital of Soochow University, Changzhou, 213000, China
| | - Xiu Han
- Department of Cell Biology, School of Medicine, Jiangsu University, Zhenjiang, 212013, China
| | - Hongjun Zou
- Department of Orthopaedics, School of Medicine, The Third Affiliated Hospital of Soochow University, Changzhou, 213000, China
| | - Bin Zhang
- Department of Laboratory Medicine, Affiliated Hospital of Jining Medical University, Jining, 272000, China
| | - Ya Ding
- Department of Orthopaedics, School of Medicine, The Third Affiliated Hospital of Soochow University, Changzhou, 213000, China
| | - Xu Xu
- Department of Orthopaedics, School of Medicine, The Third Affiliated Hospital of Soochow University, Changzhou, 213000, China
| | - Jian Zeng
- Department of Cell Biology, School of Medicine, Jiangsu University, Zhenjiang, 212013, China
| | - Jinbo Liu
- Department of Orthopaedics, School of Medicine, The Third Affiliated Hospital of Soochow University, Changzhou, 213000, China.
| | - Aihua Gong
- Department of Cell Biology, School of Medicine, Jiangsu University, Zhenjiang, 212013, China.
| |
Collapse
|
8
|
Na +/Ca 2+ exchanger 1 on nuclear envelope controls PTEN/Akt pathway via nucleoplasmic Ca 2+ regulation during neuronal differentiation. Cell Death Discov 2018. [PMID: 29531809 PMCID: PMC5841316 DOI: 10.1038/s41420-017-0018-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Nuclear envelope (NE) is a Ca2+-storing organelle controlling neuronal differentiation through nuclear Ca2+ concentrations ([Ca2+]n). However, how [Ca2+]n regulates this important function remains unknown. Here, we investigated the role of the nuclear form of the Na+/Ca2+ exchanger 1(nuNCX1) during the different stages of neuronal differentiation and the involvement of PTEN/PI3'K/Akt pathway. In neuronal cells, nuNCX1 was detected on the inner membrane of the NE where protein expression and activity of the exchanger increased during NGF-induced differentiation. nuNCX1 activation by Na+-free perfusion induced a time-dependent activation of nuclear-resident PI3K/Akt pathway in isolated nuclei. To discriminate the contribution of nuNCX1 from those of plasma membrane NCX, we generated a chimeric protein composed of the fluorophore EYFP, the exchanger inhibitory peptide, and the nuclear localization signal, named XIP-NLS. Fura-2 measurements on single nuclei and patch-clamp experiments in whole-cell configuration showed that XIP-NLS selectively inhibited nuNCX1. Once it reached the nuclear compartment, XIP-NLS increased the nucleoplasmic Ca2+ peak elicited by ATP and reduced Akt phosphorylation, GAP-43 and MAP-2 expression through nuclear-resident PTEN induction. Furthermore, in accordance with the prevention of the neuronal phenotype, XIP-NLS significantly reduced TTX-sensitive Na+ currents and membrane potential during neuronal differentiation. The selective inhibition of nuNCX1 by XIP-NLS increased the percentage of β III tubulin-positive immature neurons in mature cultures of MAP-2-positive cortical neurons, thus unraveling a new function for nuNCX1 in regulating neuronal differentiation through [Ca2+]n-dependent PTEN/PI3K/Akt pathway.
Collapse
|
9
|
Tang G, Yao J, Shen R, Ji A, Ma K, Cong B, Wang F, Zhu L, Wang X, Ding Y, Zhang B. Reduced inflammatory factor expression facilitates recovery after sciatic nerve injury in TLR4 mutant mice. Int Immunopharmacol 2018; 55:77-85. [PMID: 29227824 DOI: 10.1016/j.intimp.2017.12.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 12/05/2017] [Accepted: 12/06/2017] [Indexed: 12/11/2022]
Abstract
Toll-like receptors (TLRs) are extremely significant pattern recognition receptors. When nerve injury occurs, a variety of inflammatory factors are generated, leading to an exceedingly complex micro-environment. TLRs recognize damage-associated molecular patterns. To investigate the correlation between TLR4 and recovery after sciatic nerve injury, the model of sciatic nerve injury was conducted using TLR4-mutated mice (C3H/HeJ) and wild mice (C3H/HeN). Our goal was to identify short-stage and long-stage changes after sciatic nerve injury, mainly by checking the expression changes of inflammation factors in the short-stage and the differences in the recovery of the injured sciatic nerve in the long-stage. The results show that the increase of changes in the HeN group of IL-1β, IL-6, TNF-α and MCP-1 are more obvious than in the HeJ group, with caspase1 expression higher and Nlrp3 expression lower in the former group. Further results reveal intense inflammation occurred in the HeN group showing more neutrophils and macrophages. Nlrp3 and caspase1 showed little difference by Immunohistochemistry, with Nlrp6 expression differing between the HeJ group and the HeN group. The results led us to conclude that better recovery of the injured sciatic nerve occurred in the HeJ group because the expression of GAP-43 and p75NTR was higher and had a better SFI figure. TLR4 mutation can decrease the expression of inflammatory factors and enhance the speed of recovery after sciatic nerve injury. The changes in the expression of Nlrp6, which are related to the TLR4 mutation, may influence recovery of the injured sciatic nerve. Further studies will be conducted to confirm these results.
Collapse
Affiliation(s)
- Guoqing Tang
- Department of Immunology, Medical College of Qingdao University, Qingdao, Shandong 266071, PR China
| | - Jia Yao
- Department of Immunology, Medical College of Qingdao University, Qingdao, Shandong 266071, PR China
| | - Ruowu Shen
- Department of Anatomy, Medical College of Qingdao University, Qingdao, Shandong 266071, PR China
| | - Aiyu Ji
- Department of Traumatic Surgery, The Affiliated Hospital, Medical College of Qingdao University, Qingdao, Shandong 266003, PR China
| | - Kai Ma
- Department of Immunology, Medical College of Qingdao University, Qingdao, Shandong 266071, PR China
| | - Beibei Cong
- Department of Immunology, Medical College of Qingdao University, Qingdao, Shandong 266071, PR China
| | - Fang Wang
- Department of Immunology, Medical College of Qingdao University, Qingdao, Shandong 266071, PR China
| | - Lingyu Zhu
- Department of Immunology, Medical College of Qingdao University, Qingdao, Shandong 266071, PR China
| | - Xuan Wang
- Department of Immunology, Medical College of Qingdao University, Qingdao, Shandong 266071, PR China
| | - Yingqiao Ding
- Department of Immunology, Medical College of Qingdao University, Qingdao, Shandong 266071, PR China
| | - Bei Zhang
- Department of Immunology, Medical College of Qingdao University, Qingdao, Shandong 266071, PR China.
| |
Collapse
|
10
|
Song Z, Han X, Shen L, Zou H, Zhang B, Liu J, Gong A. PTEN silencing enhances neuronal proliferation and differentiation by activating PI3K/Akt/GSK3β pathway in vitro. Exp Cell Res 2018; 363:179-187. [PMID: 29305963 DOI: 10.1016/j.yexcr.2018.01.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 12/03/2017] [Accepted: 01/02/2018] [Indexed: 01/09/2023]
Abstract
The failure of neuronal proliferation and differentiation is a major obstacle for neural repair and regeneration after traumatic central nervous system (CNS) injury. PTEN acts as an intrinsic brake on the neuronal cells, but its roles and mechanism still remain to be clarified. Herein, for the first time we confirmed that PTEN had a dual effect on the neuronal cells in vitro. Firstly, we found that PTEN knockdown significantly promoted cell proliferation and differentiation. Then, PTEN knockdown activated PI3K/Akt and Wnt/β-catenin pathways in vitro. Further evidence revealed that GSK3β as a key node involved in PTEN controlling cell proliferation and differentiation in PC12 cells. In addition, we identified that PTEN-GSK3β pathway modulated neuronal proliferation via β-catenin. Taken together, these results suggest that PTEN silencing enhances neuronal proliferation and differentiation by activating PI3K/Akt/GSK3β pathway that it may be a promising therapeutic approach for CNS injury.
Collapse
Affiliation(s)
- Zhiwen Song
- Department of Orthopedics, The Third Affiliated Hospital of Soochow University, Changzhou 213003, China
| | - Xiu Han
- Department of Cell Biology, School of Medicine, Jiangsu University, Zhenjiang 212013, China
| | - Liming Shen
- Department of Orthopedics, The Third Affiliated Hospital of Soochow University, Changzhou 213003, China
| | - Hongjun Zou
- Department of Orthopedics, The Third Affiliated Hospital of Soochow University, Changzhou 213003, China
| | - Bin Zhang
- Department of Laboratory Medicine, Affiliated Hospital of Jining Medical University, Jining 272000, China
| | - Jinbo Liu
- Department of Orthopedics, The Third Affiliated Hospital of Soochow University, Changzhou 213003, China.
| | - Aihua Gong
- Department of Cell Biology, School of Medicine, Jiangsu University, Zhenjiang 212013, China.
| |
Collapse
|
11
|
Wu Q, Ye X, Xiong Y, Zhu H, Miao J, Zhang W, Wan J. The Protective Role of microRNA-200c in Alzheimer's Disease Pathologies Is Induced by Beta Amyloid-Triggered Endoplasmic Reticulum Stress. Front Mol Neurosci 2016; 9:140. [PMID: 28008308 PMCID: PMC5143617 DOI: 10.3389/fnmol.2016.00140] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 11/24/2016] [Indexed: 12/26/2022] Open
Abstract
MicroRNAs are small non-coding RNAs that repress the expression of their target proteins. The roles of microRNAs in the development of Alzheimer's disease (AD) are not clear. In this study we show that miR-200c represses the expression of PTEN protein. PTEN downregulation by miR-200c supports the survival and differentiation of cultured neurons. AD is a progressive neurodegenerative disease signified by beta amyloid (Aβ) peptide aggregation and deposition. In a mouse model of AD that is induced by APPswe and PS1ΔE9 double transgenes, we found Aβ deposition results in neuronal ER stress that induces miR200c. Pharmacological blockade of ER stress inhibited Aβ-induced miR-200c overexpression in AD brains. MiR-200c was detected in the serum of both AD mice and human AD patients. These findings suggest that miR-200c functions as part of the neuronal cell-intrinsic adaptive machinery, and supports neuronal survival and differentiation in response to Aβ induced ER-stress by downregulating PTEN.
Collapse
Affiliation(s)
- Qi Wu
- Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University - The Hong Kong University of Science and Technology Medical Center Shenzhen, China
| | - Xiaoyang Ye
- Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University - The Hong Kong University of Science and Technology Medical Center Shenzhen, China
| | - Yi Xiong
- Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University - The Hong Kong University of Science and Technology Medical Center Shenzhen, China
| | - Haili Zhu
- Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University - The Hong Kong University of Science and Technology Medical Center Shenzhen, China
| | - Jianting Miao
- Department of Neurology, Tangdu Hospital, Fourth Military Medical University Xi'an City, China
| | - Wei Zhang
- Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University - The Hong Kong University of Science and Technology Medical Center Shenzhen, China
| | - Jun Wan
- Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University - The Hong Kong University of Science and Technology Medical CenterShenzhen, China; Division of Life Science, The Hong Kong University of Science and TechnologyHong Kong, China
| |
Collapse
|
12
|
Lee SJ, Bui TT, Chen CHJ, Lagman C, Chung LK, Sidhu S, Seo DJ, Yong WH, Siegal TL, Kim M, Yang I. Central Neurocytoma: A Review of Clinical Management and Histopathologic Features. Brain Tumor Res Treat 2016; 4:49-57. [PMID: 27867912 PMCID: PMC5114192 DOI: 10.14791/btrt.2016.4.2.49] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 09/21/2016] [Accepted: 09/21/2016] [Indexed: 01/24/2023] Open
Abstract
Central neurocytoma (CN) is a rare, benign brain tumor often located in the lateral ventricles. CN may cause obstructive hydrocephalus and manifest as signs of increased intracranial pressure. The goal of treatment for CN is a gross total resection (GTR), which often yields excellent prognosis with a very high rate of tumor control and survival. Adjuvant radiosurgery and radiotherapy may be considered to improve tumor control when GTR cannot be achieved. Chemotherapy is also not considered a primary treatment, but has been used as a salvage therapy. The radiological features of CN are indistinguishable from those of other brain tumors; therefore, many histological markers, such as synaptophysin, can be very useful for diagnosing CNs. Furthermore, the MIB-1 Labeling Index seems to be correlated with the prognosis of CN. We also discuss oncogenes associated with these elusive tumors. Further studies may improve our ability to accurately diagnose CNs and to design the optimal treatment regimens for patients with CNs.
Collapse
Affiliation(s)
- Seung J Lee
- Department of Neurosurgery, University of California, Los Angeles, Los Angeles, CA, USA
| | - Timothy T Bui
- Department of Neurosurgery, University of California, Los Angeles, Los Angeles, CA, USA
| | - Cheng Hao Jacky Chen
- Department of Neurosurgery, University of California, Los Angeles, Los Angeles, CA, USA
| | - Carlito Lagman
- Department of Neurosurgery, University of California, Los Angeles, Los Angeles, CA, USA
| | - Lawrance K Chung
- Department of Neurosurgery, University of California, Los Angeles, Los Angeles, CA, USA
| | - Sabrin Sidhu
- Department of Neurosurgery, University of California, Los Angeles, Los Angeles, CA, USA
| | - David J Seo
- Department of Neurosurgery, University of California, Los Angeles, Los Angeles, CA, USA
| | - William H Yong
- Department of Pathology & Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Todd L Siegal
- Department of Radiology, Division of Neuroradiology, Cooper University Hospital, Camden, NJ, USA
| | - Minsu Kim
- Department of Neurosurgery, Yeungnam University College of Medicine, Daegu, Korea
| | - Isaac Yang
- Department of Neurosurgery, University of California, Los Angeles, Los Angeles, CA, USA.; Jonsson Comprehensive Cancer Center, University of California, Los Angeles, Los Angeles, CA, USA
| |
Collapse
|
13
|
Lee JE, Lim MS, Park JH, Park CH, Koh HC. PTEN Promotes Dopaminergic Neuronal Differentiation Through Regulation of ERK-Dependent Inhibition of S6K Signaling in Human Neural Stem Cells. Stem Cells Transl Med 2016; 5:1319-1329. [PMID: 27388240 DOI: 10.5966/sctm.2015-0200] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 04/18/2016] [Indexed: 02/05/2023] Open
Abstract
: Phosphatase and tension homolog (PTEN) is a widely known negative regulator of insulin/phosphatidylinositol 3-kinase (PI3K) signaling. The PI3K/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) and Ras-extracellular signal-regulated kinase (Ras-ERK) signaling pathways are the chief mechanisms controlling the survival, proliferation, and differentiation of neural stem cells (NSCs). However, the roles of PTEN in Akt/mTOR and ERK signaling during proliferation and neuronal differentiation of human NSCs (hNSCs) are poorly understood. Treatment of proliferating hNSCs with a specific inhibitor of PTEN or overexpression of the PTEN inactive mutant G129E resulted in an increase in the expression levels of Ki67, p-S6 kinase (p-S6K), and p-ERK without affecting p-Akt expression during proliferation of hNSCs. Therefore, we focused on the regulatory effect of PTEN in S6K and ERK signaling during dopaminergic neuronal differentiation of hNSCs. Overexpression of PTEN during neuronal differentiation of hNSCs caused an increase in p-S6K expression and a decrease in p-ERK expression. Conversely, inhibition of PTEN increased p-ERK expression and decreased p-S6K expression. Inhibition of ERK by a specific chemical inhibitor, U0126, promoted neuronal generation, especially of tyrosine hydroxylase-positive neurons. p-S6K expression increased in a time-dependent manner during differentiation, and this effect was enhanced by U0126. These results indicated that PTEN promoted neuronal differentiation by inhibition of ERK signaling, which in turn induced activation of S6K. Our data suggest that ERK pathways participate in crosstalk with S6K through PTEN signaling during neuronal differentiation of hNSCs. These results represent a novel pathway by which PTEN may modulate the interplay between ERK and S6K signaling, leading to increased neuronal differentiation in hNSCs. SIGNIFICANCE This article adds to the body of knowledge about the mechanism of extracellular signal-regulated kinase (ERK)-mediated differentiation by describing the molecular function of phosphatase and tension homolog (PTEN) during the neuronal differentiation of human neural stem cells (hNSCs). Previous studies showed that S6K signaling promoted neuronal differentiation in hNSCs via the phosphatidylinositol 3-kinase Akt-mammalian target of rapamycin signaling pathway. A further series of studies investigated whether this S6 kinase-induced differentiation in hNSCs involves regulation of ERK signaling by PTEN. The current study identified a novel mechanism by which PTEN regulates neuronal differentiation in hNSCs, suggesting that activating PTEN function promotes dopaminergic neuronal differentiation and providing an important resource for future studies of PTEN function.
Collapse
Affiliation(s)
- Jeong Eun Lee
- Department of Pharmacology, College of Medicine, Hanyang University, Seoul, Republic of Korea Hanyang Biomedical Research Institute, Seoul, Republic of Korea
| | - Mi Sun Lim
- Hanyang Biomedical Research Institute, Seoul, Republic of Korea Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul, Republic of Korea Research and Development Center, Jeil Pharmaceutical Company, Limited, Yongin, Republic of Korea
| | - Jae Hyeon Park
- Department of Pharmacology, College of Medicine, Hanyang University, Seoul, Republic of Korea Hanyang Biomedical Research Institute, Seoul, Republic of Korea Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul, Republic of Korea
| | - Chang Hwan Park
- Hanyang Biomedical Research Institute, Seoul, Republic of Korea Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul, Republic of Korea
| | - Hyun Chul Koh
- Department of Pharmacology, College of Medicine, Hanyang University, Seoul, Republic of Korea Hanyang Biomedical Research Institute, Seoul, Republic of Korea Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul, Republic of Korea
| |
Collapse
|
14
|
He X, Thacker S, Romigh T, Yu Q, Frazier TW, Eng C. Cytoplasm-predominant Pten associates with increased region-specific brain tyrosine hydroxylase and dopamine D2 receptors in mouse model with autistic traits. Mol Autism 2015; 6:63. [PMID: 26579216 PMCID: PMC4647625 DOI: 10.1186/s13229-015-0056-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 11/09/2015] [Indexed: 11/13/2022] Open
Abstract
Background Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders characterized by impairment in social communication/interaction and inflexible/repetitive behavior. Several lines of evidence support genetic factors as a predominant cause of ASD. Among those autism susceptibility genes that have been identified, the PTEN tumor suppressor gene, initially identified as predisposing to Cowden heritable cancer syndrome, was found to be mutated in a subset of ASD patients with extreme macrocephaly. However, the ASD-relevant molecular mechanism mediating the effect of PTEN mutations remains elusive. Methods We developed a Pten knock-in murine model to study the effects of Pten germline mutations, specifically altering subcellular localization, in ASD. Proteins were isolated from the hemispheres of the male littermates, and Western blots were performed to determine protein expression levels of tyrosine hydroxylase (TH). Immunohistochemical stains were carried out to validate the localization of TH and dopamine D2 receptors (D2R). PC12 cells ectopically expressing either wild-type or missense mutant PTEN were then compared for the differences in TH expression. Results Mice carrying Pten mutations have high TH and D2R in the striatum and prefrontal cortex. They also have increased phosphorylation of cAMP response element-binding protein (CREB) and TH. Mechanistically, PTEN downregulates TH production in PC12 cells via inhibiting the phosphoinositide 3-kinase (PI3K)/CREB signaling pathway, while PTEN reduces TH phosphorylation via suppressing MAPK pathway. Unlike wild-type PTEN but similar to the mouse knock-in mutant Pten, three naturally occurring missense mutations of PTEN that we previously identified in ASD patients, H93R, F241S, and D252G, were not able to suppress TH when overexpressed in PC12 cells. In addition, two other PTEN missense mutations, C124S (pan phosphatase dead) and G129E (lipid phosphatase dead), failed to suppress TH when ectopically expressed in PC12 cells. Conclusions Our data reveal a non-canonical PTEN-TH pathway in the brain that may work as a core regulator of dopamine signaling, which when dysfunctional is pathogenic in ASD. Electronic supplementary material The online version of this article (doi:10.1186/s13229-015-0056-6) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Xin He
- Genomic Medicine Institute, Cleveland Clinic, 9500 Euclid Avenue, Mailstop NE-50, Cleveland, OH 44195 USA ; Lerner Research Institute, Cleveland Clinic, Cleveland, OH USA
| | - Stetson Thacker
- Genomic Medicine Institute, Cleveland Clinic, 9500 Euclid Avenue, Mailstop NE-50, Cleveland, OH 44195 USA ; Lerner Research Institute, Cleveland Clinic, Cleveland, OH USA ; HHMI Graduate Program, Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH USA
| | - Todd Romigh
- Genomic Medicine Institute, Cleveland Clinic, 9500 Euclid Avenue, Mailstop NE-50, Cleveland, OH 44195 USA ; Lerner Research Institute, Cleveland Clinic, Cleveland, OH USA
| | - Qi Yu
- Genomic Medicine Institute, Cleveland Clinic, 9500 Euclid Avenue, Mailstop NE-50, Cleveland, OH 44195 USA ; Lerner Research Institute, Cleveland Clinic, Cleveland, OH USA
| | - Thomas W Frazier
- Genomic Medicine Institute, Cleveland Clinic, 9500 Euclid Avenue, Mailstop NE-50, Cleveland, OH 44195 USA ; Lerner Research Institute, Cleveland Clinic, Cleveland, OH USA ; HHMI Graduate Program, Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH USA ; Center for Autism, Pediatrics Institute, Cleveland Clinic, Cleveland, OH USA ; Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, OH USA
| | - Charis Eng
- Genomic Medicine Institute, Cleveland Clinic, 9500 Euclid Avenue, Mailstop NE-50, Cleveland, OH 44195 USA ; Lerner Research Institute, Cleveland Clinic, Cleveland, OH USA ; HHMI Graduate Program, Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH USA ; Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH USA ; Stanley Shalom Zielony Institute of Nursing Excellence, Cleveland Clinic, Cleveland, OH USA ; Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH USA ; CASE Comprehensive Cancer Center, Case Western Reserve University School of Medicine, Cleveland, OH USA
| |
Collapse
|
15
|
Stavarache MA, Musatov S, McGill M, Vernov M, Kaplitt MG. The tumor suppressor PTEN regulates motor responses to striatal dopamine in normal and Parkinsonian animals. Neurobiol Dis 2015; 82:487-494. [PMID: 26232589 DOI: 10.1016/j.nbd.2015.07.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 07/22/2015] [Accepted: 07/23/2015] [Indexed: 01/03/2023] Open
Abstract
Phosphatase and Tensin homolog deleted on chromosome 10 (PTEN) is a dual lipid-protein phosphatase known primarily as a growth preventing tumor suppressor. PTEN is also expressed in neurons, and pathways modulated by PTEN can influence neuronal function. Here we report a novel function of PTEN as a regulator of striatal dopamine signaling in a model of Parkinson's disease (PD). Blocking PTEN expression with an adeno-associated virus (AAV) vector expressing a small hairpin RNA (shRNA) resulted in reduced responses of cultured striatal neurons to dopamine, which appeared to be largely due to reduction in D2 receptor activation. Co-expression of shRNA-resistant wild-type and mutant forms of PTEN indicated that the lipid-phosphatase activity was essential for this effect. In both normal and Parkinsonian rats, inhibition of striatal PTEN in vivo resulted in motor dysfunction and impaired responses to dopamine, particularly D2 receptor agonists. Expression of PTEN mutants confirmed the lipid-phosphatase activity as critical, while co-expression of a dominant-negative form of Akt overcame the PTEN shRNA effect. These results identify PTEN as a key mediator of striatal responses to dopamine, and suggest that drugs designed to potentiate PTEN expression or activity, such as cancer chemotherapeutics, may also be useful for improving striatal responses to dopamine in conditions of dopamine depletion such as PD. This also suggests that strategies which increase Akt or decrease PTEN expression or function, such as growth factors to prevent neuronal death, may have a paradoxical effect on neurological functioning by inhibiting striatal responses to dopamine.
Collapse
Affiliation(s)
- Mihaela A Stavarache
- Laboratory of Molecular Neurosurgery, Department of Neurological Surgery, Weill Cornell Medical College, New York, NY 10065, USA
| | - Sergei Musatov
- Laboratory of Molecular Neurosurgery, Department of Neurological Surgery, Weill Cornell Medical College, New York, NY 10065, USA
| | - Marlon McGill
- Laboratory of Molecular Neurosurgery, Department of Neurological Surgery, Weill Cornell Medical College, New York, NY 10065, USA
| | - Mary Vernov
- Laboratory of Molecular Neurosurgery, Department of Neurological Surgery, Weill Cornell Medical College, New York, NY 10065, USA
| | - Michael G Kaplitt
- Laboratory of Molecular Neurosurgery, Department of Neurological Surgery, Weill Cornell Medical College, New York, NY 10065, USA.
| |
Collapse
|
16
|
Martin NE, Gerke T, Sinnott JA, Stack EC, Andrén O, Andersson SO, Johansson JE, Fiorentino M, Finn S, Fedele G, Stampfer M, Kantoff PW, Mucci LA, Loda M. Measuring PI3K Activation: Clinicopathologic, Immunohistochemical, and RNA Expression Analysis in Prostate Cancer. Mol Cancer Res 2015; 13:1431-40. [PMID: 26124442 DOI: 10.1158/1541-7786.mcr-14-0569] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 06/12/2015] [Indexed: 12/16/2022]
Abstract
UNLABELLED Assessing the extent of PI3K pathway activity in cancer is vital to predicting sensitivity to PI3K-targeting drugs, but the best biomarker of PI3K pathway activity in archival tumor specimens is unclear. Here, PI3K pathway activation was assessed, in clinical tissue from 1,021 men with prostate cancers, using multiple pathway nodes that include PTEN, phosphorylated AKT (pAKT), phosphorylated ribosomal protein S6 (pS6), and stathmin. Based on these markers, a 9-point score of PI3K activation was created using the combined intensity of the 4-markers and analyzed its association with proliferation (Ki67), apoptosis (TUNEL), and androgen receptor (AR) status, as well as pathologic features and cancer-specific outcomes. In addition, the PI3K activation score was compared with mRNA expression profiling data for a large subset of men. Interestingly, those tumors with higher PI3K activation scores also had higher Gleason grade (P = 0.006), increased AR (r = 0.37; P < 0.001) and Ki67 (r = 0.24; P < 0.001), and decreased TUNEL (r = -0.12; P = 0.003). Although the PI3K activation score was not associated with an increased risk of lethal outcome, a significant interaction between lethal outcome, Gleason and high PI3K score (P = 0.03) was observed. Finally, enrichment of PI3K-specific pathways was found in the mRNA expression patterns differentiating the low and high PI3K activation scores; thus, the 4-marker IHC score of PI3K pathway activity correlates with features of PI3K activation. IMPLICATIONS The relationship of this activation score to sensitivity to anti-PI3K agents remains to be tested but may provide more precision guidance when selecting patients for these therapies.
Collapse
Affiliation(s)
- Neil E Martin
- Department of Radiation Oncology, Brigham and Women's Hospital/Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts.
| | - Travis Gerke
- Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts
| | - Jennifer A Sinnott
- Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts. Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Edward C Stack
- Center for Molecular Oncologic Pathology, Dana-Farber Cancer Institute, Boston, Massachusetts. Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts. Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts
| | - Ove Andrén
- School of Health and Medical Sciences, Örebro University; and Department of Urology, Örebro University Hospital, Örebro, Sweden
| | - Swen-Olof Andersson
- School of Health and Medical Sciences, Örebro University; and Department of Urology, Örebro University Hospital, Örebro, Sweden
| | - Jan-Erik Johansson
- School of Health and Medical Sciences, Örebro University; and Department of Urology, Örebro University Hospital, Örebro, Sweden
| | - Michelangelo Fiorentino
- Center for Molecular Oncologic Pathology, Dana-Farber Cancer Institute, Boston, Massachusetts. Pathology Unit, Addarii Institute, S Orsola-Malpighi Hospital, Bologna, Italy
| | - Stephen Finn
- Center for Molecular Oncologic Pathology, Dana-Farber Cancer Institute, Boston, Massachusetts. Department of Pathology, Trinity College, Dublin, Ireland
| | - Giuseppe Fedele
- Center for Molecular Oncologic Pathology, Dana-Farber Cancer Institute, Boston, Massachusetts
| | - Meir Stampfer
- Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts. Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Philip W Kantoff
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts
| | - Lorelei A Mucci
- Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts. Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Massimo Loda
- Center for Molecular Oncologic Pathology, Dana-Farber Cancer Institute, Boston, Massachusetts. Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts. Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts. Broad Institute of Harvard and MIT, Cambridge, Massachusetts. Division of Cancer Studies, King's College London, London, United Kingdom
| |
Collapse
|
17
|
Ventresca EM, Lecht S, Jakubowski P, Chiaverelli RA, Weaver M, Del Valle L, Ettinger K, Gincberg G, Priel A, Braiman A, Lazarovici P, Lelkes PI, Marcinkiewicz C. Association of p75(NTR) and α9β1 integrin modulates NGF-dependent cellular responses. Cell Signal 2015; 27:1225-36. [PMID: 25748048 DOI: 10.1016/j.cellsig.2015.02.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 02/06/2015] [Accepted: 02/23/2015] [Indexed: 01/10/2023]
Abstract
Direct interaction of α9β1 integrin with nerve growth factor (NGF) has been previously reported to induce pro-proliferative and pro-survival activities of non-neuronal cells. We investigated participation of p75(NTR) in α9β1 integrin-dependent cellular response to NGF stimulation. Using selective transfection of glioma cell lines with these receptors, we showed a strong, cation-independent association of α9 integrin subunit with p75(NTR) on the cellular membrane by selective immunoprecipitation experiments. The presence of the α9/p75(NTR) complex increases NGF-dependent cell adhesion, proliferation and migration. Other integrin subunits including β1 were not found in complex with p75(NTR). FRET analysis indicated that p75(NTR) and α9 integrin subunit are not closely associated through their cytoplasmic domains, most probably because of the molecular interference with other cytoplasmic proteins such as paxillin. Interaction of α9β1 integrin with another ligand, VCAM-1 was not modulated by the p75(NTR). α9/p75(NTR) complex elevated NGF-dependent activation of MAPK Erk1/2 arty for integrin that may create active complexes with other types of receptors belonging to the TNF superfamily.
Collapse
Affiliation(s)
- Erin M Ventresca
- CoE Department of Bioengineering, Temple University, Philadelphia, PA, USA
| | - Shimon Lecht
- CoE Department of Bioengineering, Temple University, Philadelphia, PA, USA
| | - Piotr Jakubowski
- CoE Department of Bioengineering, Temple University, Philadelphia, PA, USA
| | | | - Michael Weaver
- Department of Neurosurgery, Temple University Hospital, Philadelphia, PA, USA
| | - Luis Del Valle
- Department of Medicine and Pathology, Stanley Scott Cancer Center, Louisiana State University, New Orleans, LA, USA
| | - Keren Ettinger
- School of Pharmacy, Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Galit Gincberg
- School of Pharmacy, Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Avi Priel
- School of Pharmacy, Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Alex Braiman
- The Shraga Segal Department of Microbiology, Immunology and Genetics, The Faculty of Health Science, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Philip Lazarovici
- CoE Department of Bioengineering, Temple University, Philadelphia, PA, USA; School of Pharmacy, Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Peter I Lelkes
- CoE Department of Bioengineering, Temple University, Philadelphia, PA, USA
| | | |
Collapse
|
18
|
Zou H, Ding Y, Wang K, Xiong E, Peng W, Du F, Zhang Z, Liu J, Gong A. MicroRNA-29A/PTEN pathway modulates neurite outgrowth in PC12 cells. Neuroscience 2015; 291:289-300. [PMID: 25665754 DOI: 10.1016/j.neuroscience.2015.01.055] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 12/30/2014] [Accepted: 01/23/2015] [Indexed: 02/01/2023]
Abstract
PTEN serves as an intrinsic brake on neurite outgrowth, but the regulatory mechanism that governs its action is not clear. In the present study, miR-29a was found to increase neurite outgrowth by decreasing PTEN expression. Results showed that miR-92a-1, miR-29a, miR-92b, and miR-29c expression levels increased during nerve growth factor (NGF)-induced differentiation of PC12 cells. Based on in silico analysis of possible miR-29a targets, PTEN mRNA may be a binding site for miR-29a. A protein expression assay and luciferase reporter assay showed that miR-29a could directly target the 3'-UTRs (untranslated regions) of PTEN mRNA and down-regulate the expression of PTEN. PC12 cells infected with lentiviral pLKO-miR-29a showed far higher levels of miR-29a and Akt phosphorylation level than those infected with control. This promoted neurite outgrowth of PC12 cells. Collectively, these results indicate that miR-29a is an important regulator of neurite outgrowth via targeting PTEN and that it may be a promising therapeutic target for neural disease.
Collapse
Affiliation(s)
- H Zou
- Department of Orthopedics, The Third Affiliated Hospital of Suzhou University, Changzhou 213003, China
| | - Y Ding
- Department of Orthopedics, The Third Affiliated Hospital of Suzhou University, Changzhou 213003, China
| | - K Wang
- Department of Orthopedics, The Third Affiliated Hospital of Suzhou University, Changzhou 213003, China
| | - E Xiong
- School of Medicine, Jiangsu University, Zhenjiang 212013, China
| | - W Peng
- School of Medicine, Jiangsu University, Zhenjiang 212013, China
| | - F Du
- School of Medicine, Jiangsu University, Zhenjiang 212013, China
| | - Z Zhang
- School of Medicine, Jiangsu University, Zhenjiang 212013, China
| | - J Liu
- Department of Orthopedics, The Third Affiliated Hospital of Suzhou University, Changzhou 213003, China.
| | - A Gong
- School of Medicine, Jiangsu University, Zhenjiang 212013, China.
| |
Collapse
|
19
|
Secondo A, Esposito A, Sirabella R, Boscia F, Pannaccione A, Molinaro P, Cantile M, Ciccone R, Sisalli MJ, Scorziello A, Di Renzo G, Annunziato L. Involvement of the Na+/Ca2+ exchanger isoform 1 (NCX1) in neuronal growth factor (NGF)-induced neuronal differentiation through Ca2+-dependent Akt phosphorylation. J Biol Chem 2014; 290:1319-31. [PMID: 25416782 DOI: 10.1074/jbc.m114.555516] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
NGF induces neuronal differentiation by modulating [Ca(2+)]i. However, the role of the three isoforms of the main Ca(2+)-extruding system, the Na(+)/Ca(2+) exchanger (NCX), in NGF-induced differentiation remains unexplored. We investigated whether NCX1, NCX2, and NCX3 isoforms could play a relevant role in neuronal differentiation through the modulation of [Ca(2+)]i and the Akt pathway. NGF caused progressive neurite elongation; a significant increase of the well known marker of growth cones, GAP-43; and an enhancement of endoplasmic reticulum (ER) Ca(2+) content and of Akt phosphorylation through an early activation of ERK1/2. Interestingly, during NGF-induced differentiation, the NCX1 protein level increased, NCX3 decreased, and NCX2 remained unaffected. At the same time, NCX total activity increased. Moreover, NCX1 colocalized and coimmunoprecipitated with GAP-43, and NCX1 silencing prevented NGF-induced effects on GAP-43 expression, Akt phosphorylation, and neurite outgrowth. On the other hand, the overexpression of its neuronal splicing isoform, NCX1.4, even in the absence of NGF, induced an increase in Akt phosphorylation and GAP-43 protein expression. Interestingly, tetrodotoxin-sensitive Na(+) currents and 1,3-benzenedicarboxylic acid, 4,4'-[1,4,10-trioxa-7,13-diazacyclopentadecane-7,13-diylbis(5-methoxy-6,12-benzofurandiyl)]bis-, tetrakis[(acetyloxy)methyl] ester-detected [Na(+)]i significantly increased in cells overexpressing NCX1.4 as well as ER Ca(2+) content. This latter effect was prevented by tetrodotoxin. Furthermore, either the [Ca(2+)]i chelator(1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid) (BAPTA-AM) or the PI3K inhibitor LY 294002 prevented Akt phosphorylation and GAP-43 protein expression rise in NCX1.4 overexpressing cells. Moreover, in primary cortical neurons, NCX1 silencing prevented Akt phosphorylation, GAP-43 and MAP2 overexpression, and neurite elongation. Collectively, these data show that NCX1 participates in neuronal differentiation through the modulation of ER Ca(2+) content and PI3K signaling.
Collapse
Affiliation(s)
- Agnese Secondo
- From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and
| | - Alba Esposito
- From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and
| | - Rossana Sirabella
- the Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) SDN, Naples 80143, Italy
| | - Francesca Boscia
- From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and
| | - Anna Pannaccione
- From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and
| | - Pasquale Molinaro
- From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and
| | - Maria Cantile
- From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and
| | - Roselia Ciccone
- From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and
| | - Maria Josè Sisalli
- From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and
| | - Antonella Scorziello
- From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and
| | - Gianfranco Di Renzo
- From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and
| | - Lucio Annunziato
- From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and the Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) SDN, Naples 80143, Italy
| |
Collapse
|
20
|
Veleva-Rotse BO, Barnes AP. Brain patterning perturbations following PTEN loss. Front Mol Neurosci 2014; 7:35. [PMID: 24860420 PMCID: PMC4030135 DOI: 10.3389/fnmol.2014.00035] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 04/15/2014] [Indexed: 12/23/2022] Open
Abstract
This review will consider the impact of compromised PTEN signaling in brain patterning. We approach understanding the contribution of PTEN to nervous system development by surveying the findings from the numerous genetic loss-of-function models that have been generated as well as other forms of PTEN inactivation. By exploring the developmental programs influenced by this central transduction molecule, we can begin to understand the molecular mechanisms that shape the developing brain. A wealth of data indicates that PTEN plays critical roles in a variety of stages during brain development. Many of them are considered here including: stem cell proliferation, fate determination, polarity, migration, process outgrowth, myelination and somatic hypertrophy. In many of these contexts, it is clear that PTEN phosphatase activity contributes to the observed effects of genetic deletion or depletion, however recent studies have also ascribed non-catalytic functions to PTEN in regulating cell function. We also explore the potential impact this alternative pool of PTEN may have on the developing brain. Together, these elements begin to form a clearer picture of how PTEN contributes to the emergence of brain structure and binds form and function in the nervous system.
Collapse
Affiliation(s)
- Biliana O Veleva-Rotse
- Neuroscience Graduate Program, Oregon Health and Science University Portland, OR, USA ; Department of Pediatrics, Oregon Health and Science University Portland, OR, USA
| | - Anthony P Barnes
- Neuroscience Graduate Program, Oregon Health and Science University Portland, OR, USA ; Department of Pediatrics, Oregon Health and Science University Portland, OR, USA ; Department of Cell and Developmental Biology, Oregon Health and Science University Portland, OR, USA
| |
Collapse
|
21
|
Clipperton-Allen AE, Page DT. Pten haploinsufficient mice show broad brain overgrowth but selective impairments in autism-relevant behavioral tests. Hum Mol Genet 2014; 23:3490-505. [PMID: 24497577 DOI: 10.1093/hmg/ddu057] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Accelerated head and brain growth (macrocephaly) during development is a replicated biological finding in a subset of individuals with autism spectrum disorder (ASD). However, the relationship between brain overgrowth and the behavioral and cognitive symptoms of ASD is poorly understood. The PI3K-Akt-mTOR pathway regulates cellular growth; several genes encoding negative regulators of this pathway are ASD risk factors, including PTEN. Mutations in PTEN have been reported in individuals with ASD and macrocephaly. We report that brain overgrowth is widespread in Pten germline haploinsufficient (Pten(+/-)) mice, reflecting Pten mRNA expression in the developing brain. We then ask if broad brain overgrowth translates into general or specific effects on the development of behavior and cognition by testing Pten(+/-) mice using assays relevant to ASD and comorbidities. Deficits in social behavior were observed in both sexes. Males also showed abnormalities related to repetitive behavior and mood/anxiety. Females exhibited circadian activity and emotional learning phenotypes. Widespread brain overgrowth together with selective behavioral impairments in Pten(+/-) mice raises the possibility that most brain areas and constituent cell types adapt to an altered trajectory of growth with minimal impact on the behaviors tested in our battery; however, select areas/cell types relevant to social behavior are more vulnerable or less adaptable, thus resulting in social deficits. Probing dopaminergic neurons as a candidate vulnerable cell type, we found social behavioral impairments in mice with Pten conditionally inactivated in dopaminergic neurons that are consistent with the possibility that desynchronized growth in key cell types may contribute to ASD endophenotypes.
Collapse
Affiliation(s)
- Amy E Clipperton-Allen
- Department of Neuroscience, The Scripps Research Institute, 130 Scripps Way, Jupiter 33458, FL, USA
| | - Damon T Page
- Department of Neuroscience, The Scripps Research Institute, 130 Scripps Way, Jupiter 33458, FL, USA
| |
Collapse
|
22
|
Patel DM, Schmidt RF, Liu JK. Update on the diagnosis, pathogenesis, and treatment strategies for central neurocytoma. J Clin Neurosci 2013; 20:1193-9. [DOI: 10.1016/j.jocn.2013.01.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 01/10/2013] [Indexed: 01/19/2023]
|
23
|
Phosphatidylinositol 4-phosphate 5-kinase α negatively regulates nerve growth factor-induced neurite outgrowth in PC12 cells. Exp Mol Med 2013; 45:e16. [PMID: 23538529 PMCID: PMC3641393 DOI: 10.1038/emm.2013.18] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Neurite outgrowth, a cell differentiation process involving membrane morphological changes, is critical for neuronal network and development. The membrane lipid, phosphatidylinositol (PI) 4,5-bisphosphate (PIP2), is a key regulator of many important cell surface events of membrane signaling, trafficking and dynamics. This lipid is produced mainly by the type I PI 4-phosphate 5-kinase (PIP5K) family members. In this study, we addressed whether PIP5Kα, an isoform of PIP5K, could have a role in neurite outgrowth induced by nerve growth factor (NGF). For this purpose, we knocked down PIP5Kα in PC12 rat pheochromocytoma cells by stable expression of PIP5Kα microRNA that significantly reduced PIP5Kα expression and PIP2 level. Interestingly, NGF-induced neurite outgrowth was more prominent in PIP5Kα-knockdown (KD) cells than in control cells. Conversely, add-back of PIP5Kα into PIP5Kα KD cells abrogated the effect of NGF on neurite outgrowth. NGF treatment activated PI 3-kinase (PI3K)/Akt pathway, which seemed to be associated with reactive oxygen species generation. Similar to the changes in neurite outgrowth, the PI3K/Akt activation by NGF was potentiated by PIP5Kα KD, but was attenuated by the reintroduction of PIP5Kα. Moreover, exogenously applied PIP2 to PIP5Kα KD cells also suppressed Akt activation by NGF. Together, our results suggest that PIP5Kα acts as a negative regulator of NGF-induced neurite outgrowth by inhibiting PI3K/Akt signaling pathway in PC12 cells.
Collapse
|
24
|
Li PP, Peng HB. Regulation of axonal growth and neuromuscular junction formation by neuronal phosphatase and tensin homologue signaling. Mol Biol Cell 2012; 23:4109-17. [PMID: 22918949 PMCID: PMC3469524 DOI: 10.1091/mbc.e12-05-0367] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Axonal growth and synaptogenesis are sequential events of neuronal development. Phosphatase and tensin homologue (PTEN) is expressed in motor neurons, and its disruption leads to continued axonal extension, even upon muscle contact, leading to synaptogenic suppression. Thus PTEN is involved in target-mediated cessation of axonal growth and subsequent synaptic differentiation. During the development of the vertebrate neuromuscular junction (NMJ), motor axon tips stop growing after contacting muscle and transform into presynaptic terminals that secrete the neurotransmitter acetylcholine and activate postsynaptic ACh receptors (AChRs) to trigger muscle contraction. The neuron-intrinsic signaling that retards axonal growth to facilitate stable nerve–muscle interaction and synaptogenesis is poorly understood. In this paper, we report a novel function of presynaptic signaling by phosphatase and tensin homologue (PTEN) in mediating a growth-to-synaptogenesis transition in neurons. In Xenopus nerve–muscle cocultures, axonal growth speed was halved after contact with muscle, when compared with before contact, but when cultures were exposed to the PTEN blocker bisperoxo (1,10-phenanthroline) oxovanadate, axons touching muscle grew ∼50% faster than their counterparts in control cultures. Suppression of neuronal PTEN expression using morpholinos or the forced expression of catalytically inactive PTEN in neurons also resulted in faster than normal axonal advance after contact with muscle cells. Significantly, interference with PTEN by each of these methods also led to reduced AChR clustering at innervation sites in muscle, indicating that disruption of neuronal PTEN signaling inhibited NMJ assembly. We thus propose that PTEN-dependent slowing of axonal growth enables the establishment of stable nerve–muscle contacts that develop into NMJs.
Collapse
Affiliation(s)
- Pan P Li
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | | |
Collapse
|
25
|
Dedoni S, Olianas MC, Ingianni A, Onali P. Type I interferons impair BDNF-induced cell signaling and neurotrophic activity in differentiated human SH-SY5Y neuroblastoma cells and mouse primary cortical neurons. J Neurochem 2012; 122:58-71. [PMID: 22533963 DOI: 10.1111/j.1471-4159.2012.07766.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Type I interferons (IFNs) have been shown to act on neurons and to cause neuronal damage through mechanisms not completely defined. Here, we investigated the effects of type I IFNs on brain-derived neurotrophic factor (BDNF)-induced TrkB receptor signaling and neurotrophic activity. In retinoic acid-treated human SH-SY5Y neuroblastoma cells and mouse primary cortical neurons, long-term exposure to IFNs curtailed BDNF-induced activation of phosphatidylinositol 3-kinase, phospholipase Cγ and extracellular-regulated kinases 1 and 2 signaling. Moreover, IFN-β inhibited BDNF-induced cell survival, neurite outgrowth, and expression of neuronal markers, such as neurofilament proteins, growth-associated protein-43 and glutamate α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor subunit GluR1. The IFN inhibitory effects were associated with down-regulation of TrkB and inhibition of TrkB autophosphorylation. In SH-SY5Y cells, blockade of either Janus kinase with pyridone 6 or signal transducer and activator of transcription (STAT) 1 with siRNA transfection attenuated IFN-β-induced TrkB down-regulation. Quantitative real time RT-PCR indicated that IFN-β significantly reduced TrkB mRNA levels. Moreover, blockade of protein kinase R counteracted IFN-β-induced inhibition of TrkB expression and signaling. These data indicate that in neuronal cells IFNs negatively regulate BDNF signaling and neurotrophic activity through inhibition of TrkB activation and Janus kinase/Signal transducer and activator of transcription-dependent down-regulation of TrkB.
Collapse
Affiliation(s)
- Simona Dedoni
- Department of Neuroscience, University of Cagliari, Cagliari, Italy
| | | | | | | |
Collapse
|
26
|
Thanseem I, Anitha A, Nakamura K, Suda S, Iwata K, Matsuzaki H, Ohtsubo M, Ueki T, Katayama T, Iwata Y, Suzuki K, Minoshima S, Mori N. Elevated transcription factor specificity protein 1 in autistic brains alters the expression of autism candidate genes. Biol Psychiatry 2012; 71:410-8. [PMID: 22030357 DOI: 10.1016/j.biopsych.2011.09.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 09/08/2011] [Accepted: 09/10/2011] [Indexed: 01/09/2023]
Abstract
BACKGROUND Profound changes in gene expression can result from abnormalities in the concentrations of sequence-specific transcription factors like specificity protein 1 (Sp1). Specificity protein 1 binding sites have been reported in the promoter regions of several genes implicated in autism. We hypothesize that dysfunction of Sp1 could affect the expression of multiple autism candidate genes, contributing to the heterogeneity of autism. METHODS We assessed any alterations in the expression of Sp1 and that of autism candidate genes in the postmortem brain (anterior cingulate gyrus [ACG], motor cortex, and thalamus) of autism patients (n = 8) compared with healthy control subjects (n = 13). Alterations in the expression of candidate genes upon Sp1/DNA binding inhibition with mithramycin and Sp1 silencing by RNAi were studied in SK-N-SH neuronal cells. RESULTS We observed elevated expression of Sp1 in ACG of autism patients (p = .010). We also observed altered expression of several autism candidate genes. GABRB3, RELN, and HTR2A showed reduced expression, whereas CD38, ITGB3, MAOA, MECP2, OXTR, and PTEN showed elevated expression in autism. In SK-N-SH cells, OXTR, PTEN, and RELN showed reduced expression upon Sp1/DNA binding inhibition and Sp1 silencing. The RNA integrity number was not available for any of the samples. CONCLUSIONS Transcription factor Sp1 is dysfunctional in the ACG of autistic brain. Consequently, the expression of potential autism candidate genes regulated by Sp1, especially OXTR and PTEN, could be affected. The diverse downstream pathways mediated by the Sp1-regulated genes, along with the environmental and intracellular signal-related regulation of Sp1, could explain the complex phenotypes associated with autism.
Collapse
Affiliation(s)
- Ismail Thanseem
- Department of Psychiatry and Neurology, Hamamatsu University School of Medicine, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Shohat M, Ben-Meir D, Lavi S. Protein phosphatase magnesium dependent 1A (PPM1A) plays a role in the differentiation and survival processes of nerve cells. PLoS One 2012; 7:e32438. [PMID: 22384250 PMCID: PMC3288098 DOI: 10.1371/journal.pone.0032438] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 01/27/2012] [Indexed: 12/22/2022] Open
Abstract
The serine/threonine phosphatase type 2C (PPM1A) has a broad range of substrates, and its role in regulating stress response is well established. We have investigated the involvement of PPM1A in the survival and differentiation processes of PC6-3 cells, a subclone of the PC12 cell line. This cell line can differentiate into neuron like cells upon exposure to nerve growth factor (NGF). Overexpression of PPM1A in naive PC6-3 cells caused cell cycle arrest at the G2/M phase followed by apoptosis. Interestingly, PPM1A overexpression did not affect fully differentiated cells. Using PPM1A overexpressing cells and PPM1A knockdown cells, we show that this phosphatase affects NGF signaling in PC6-3 cells and is engaged in neurite outgrowth. In addition, the ablation of PPM1A interferes with NGF-induced growth arrest during differentiation of PC6-3 cells.
Collapse
Affiliation(s)
| | | | - Sara Lavi
- Department of Cell Research and Immunology, Tel Aviv University, Tel Aviv, Israel
- * E-mail:
| |
Collapse
|
28
|
Lerch JK, Kuo F, Motti D, Morris R, Bixby JL, Lemmon VP. Isoform diversity and regulation in peripheral and central neurons revealed through RNA-Seq. PLoS One 2012; 7:e30417. [PMID: 22272348 PMCID: PMC3260295 DOI: 10.1371/journal.pone.0030417] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 12/15/2011] [Indexed: 11/19/2022] Open
Abstract
To fully understand cell type identity and function in the nervous system there is a need to understand neuronal gene expression at the level of isoform diversity. Here we applied Next Generation Sequencing of the transcriptome (RNA-Seq) to purified sensory neurons and cerebellar granular neurons (CGNs) grown on an axonal growth permissive substrate. The goal of the analysis was to uncover neuronal type specific isoforms as a prelude to understanding patterns of gene expression underlying their intrinsic growth abilities. Global gene expression patterns were comparable to those found for other cell types, in that a vast majority of genes were expressed at low abundance. Nearly 18% of gene loci produced more than one transcript. More than 8000 isoforms were differentially expressed, either to different degrees in different neuronal types or uniquely expressed in one or the other. Sensory neurons expressed a larger number of genes and gene isoforms than did CGNs. To begin to understand the mechanisms responsible for the differential gene/isoform expression we identified transcription factor binding sites present specifically in the upstream genomic sequences of differentially expressed isoforms, and analyzed the 3′ untranslated regions (3′ UTRs) for microRNA (miRNA) target sites. Our analysis defines isoform diversity for two neuronal types with diverse axon growth capabilities and begins to elucidate the complex transcriptional landscape in two neuronal populations.
Collapse
Affiliation(s)
- Jessica K. Lerch
- The Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
| | - Frank Kuo
- The Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
| | - Dario Motti
- The Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
| | - Richard Morris
- The Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
- The Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
| | - John L. Bixby
- The Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
- The Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
- Department of Cellular and Molecular Pharmacology, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
- * E-mail: (VPL); (JLB)
| | - Vance P. Lemmon
- The Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
- Department of Neurological Surgery, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
- * E-mail: (VPL); (JLB)
| |
Collapse
|
29
|
Christensen R, de la Torre-Ubieta L, Bonni A, Colón-Ramos DA. A conserved PTEN/FOXO pathway regulates neuronal morphology during C. elegans development. Development 2012; 138:5257-67. [PMID: 22069193 PMCID: PMC3210501 DOI: 10.1242/dev.069062] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The phosphatidylinositol 3-kinase (PI3K) signaling pathway is a conserved signal transduction cascade that is fundamental for the correct development of the nervous system. The major negative regulator of PI3K signaling is the lipid phosphatase DAF-18/PTEN, which can modulate PI3K pathway activity during neurodevelopment. Here, we identify a novel role for DAF-18 in promoting neurite outgrowth during development in Caenorhabditis elegans. We find that DAF-18 modulates the PI3K signaling pathway to activate DAF-16/FOXO and promote developmental neurite outgrowth. This activity of DAF-16 in promoting outgrowth is isoform-specific, being effected by the daf-16b isoform but not the daf-16a or daf-16d/f isoform. We also demonstrate that the capacity of DAF-16/FOXO in regulating neuron morphology is conserved in mammalian neurons. These data provide a novel mechanism by which the conserved PI3K signaling pathway regulates neuronal cell morphology during development through FOXO.
Collapse
Affiliation(s)
- Ryan Christensen
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Department of Cell Biology, Yale University School of Medicine, P.O. Box 9812, New Haven, CT 06536-0812, USA
| | | | | | | |
Collapse
|
30
|
Yoon C, Tuszynski MH. Frontiers of spinal cord and spine repair: experimental approaches for repair of spinal cord injury. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 760:1-15. [PMID: 23281510 DOI: 10.1007/978-1-4614-4090-1_1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Regeneration of injured CNS neurons was once thought to be an unachievable goal. Most patients with significant damage to the spinal cord suffer from permanently impaired neurological function. A century of research, however, has led to an understanding of multiple factors that limit CNS regeneration and from this knowledge experimental strategies have emerged for enhancing CNS repair. Some of these approaches have undergone human translation. Nevertheless, translating experimental findings to human trials has been more challenging than anticipated. In this chapter, we will review the current state of knowledge regarding central axonal growth failure after injury, and approaches taken to enhance recovery after SCI.
Collapse
Affiliation(s)
- Choya Yoon
- Department of Neurosciences, University of California San Diego, La Jolla, California, USA.
| | | |
Collapse
|
31
|
Sugimoto N, Miwa S, Ohno-Shosaku T, Tsuchiya H, Hitomi Y, Nakamura H, Tomita K, Yachie A, Koizumi S. Activation of tumor suppressor protein PTEN and induction of apoptosis are involved in cAMP-mediated inhibition of cell number in B92 glial cells. Neurosci Lett 2011; 497:55-9. [PMID: 21529704 DOI: 10.1016/j.neulet.2011.04.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Revised: 04/05/2011] [Accepted: 04/12/2011] [Indexed: 01/08/2023]
Abstract
During brain development, cAMP induces morphological changes and inhibits growth effects in several cell types. However, the molecular mechanisms underlying the growth inhibition remain unknown. Tumor suppressor protein phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a lipid phosphatase that inhibits the phosphoinositide 3-kinase (PI3K) pathway. The phosphorylation of Akt, which is one of the key molecules downstream of PI3K, inhibits apoptosis. In this study, we investigated the role of PTEN in cAMP-mediated growth inhibition. B92 rat glial cells were treated with 2 different cAMP stimulatory agents, a phosphodiesterase (PDE) inhibitor and a β-adrenoceptor agonist. Both cAMP stimulatory agents induced marked morphological changes in the cells, decreased cell number, decreased Akt phosphorylation, activated PTEN, cleaved caspase-3, and induced the condensation and fragmentation of nuclei. These results indicate that the cAMP stimulatory agents induced apoptosis. Protein phosphatase inhibitor prevented cAMP-induced dephosphorylation of PTEN and Akt. In addition, cAMP analogs and Epac-selective agonists affected PTEN and Akt activities. These results suggested that cAMP-induced apoptosis may be mediated by PTEN activation and Akt inhibition through protein phosphatase in B92 cells. Our results provide new insight into the role of PTEN in cAMP-induced apoptosis in glial cells.
Collapse
Affiliation(s)
- Naotoshi Sugimoto
- Department of Physiology, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Ishikawa, Kanazawa 920-8640, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Jia L, Ji S, Maillet JC, Zhang X. PTEN suppression promotes neurite development exclusively in differentiating PC12 cells via PI3-kinase and MAP kinase signaling. J Cell Biochem 2011; 111:1390-400. [PMID: 20830745 DOI: 10.1002/jcb.22867] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
As a dual-specificity phosphatase catalyzing the dephosphorylation of phosphatidylinositols and protein substrates, PTEN is critically involved in the nervous system development. However, the regulatory role of PTEN in neurite outgrowth is still controversial, and the downstream signaling events remain elusive. Here, we show that PTEN knockdown promoted the proliferation and survival but not the neurite outgrowth of rat pheochromocytoma PC12 cells when exposed to nerve growth factor (NGF). In contrast, selective PTEN silencing in differentiating PC12 cells that express nestin significantly facilitated neurite elongation. Elevated Akt and Erk1/2 phosphorylation was involved in accelerated NGF-induced neurite development of PC12 cells following PTEN knockdown. Discriminated roles of the lipid phosphatase and protein phosphatase activities of PTEN in neurite development, as well as the detailed molecular profiles affected by these phosphatase activities, were defined by restored expression of a lipid phosphatase-deficient PTEN mutant following endogenous PTEN silencing in PC12 cells. Our study suggests an overall inhibitory effect of PTEN in neurite development reconciled by a probably indispensable role of this phosphatase in the initiation of PC12 cell differentiation.
Collapse
Affiliation(s)
- Lintao Jia
- Department of Biochemistry and Molecular Biology, Fourth Military Medical University, Xi'an 710032, China.
| | | | | | | |
Collapse
|
33
|
Ariza CA, Fleury AT, Tormos CJ, Petruk V, Chawla S, Oh J, Sakaguchi DS, Mallapragada SK. The influence of electric fields on hippocampal neural progenitor cells. Stem Cell Rev Rep 2011; 6:585-600. [PMID: 20665129 DOI: 10.1007/s12015-010-9171-0] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The differentiation and proliferation of neural stem/progenitor cells (NPCs) depend on various in vivo environmental factors or cues, which may include an endogenous electrical field (EF), as observed during nervous system development and repair. In this study, we investigate the morphologic, phenotypic, and mitotic alterations of adult hippocampal NPCs that occur when exposed to two EFs of estimated endogenous strengths. NPCs treated with a 437 mV/mm direct current (DC) EF aligned perpendicularly to the EF vector and had a greater tendency to differentiate into neurons, but not into oligodendrocytes or astrocytes, compared to controls. Furthermore, NPC process growth was promoted perpendicularly and inhibited anodally in the 437 mV/mm DC EF. Yet fewer cells were observed in the DC EF, which in part was due to a decrease in cell viability. The other EF applied was a 46 mV/mm alternating current (AC) EF. However, the 46 mV/mm AC EF showed no major differences in alignment or differentiation, compared to control conditions. For both EF treatments, the percent of mitotic cells during the last 14 h of the experiment were statistically similar to controls. Reported here, to our knowledge, is the first evidence of adult NPC differentiation affected in an EF in vitro. Further investigation and application of EFs on stem cells is warranted to elucidate the utility of EFs to control phenotypic behavior. With progress, the use of EFs may be engineered to control differentiation and target the growth of transplanted cells in a stem cell-based therapy to treat nervous system disorders.
Collapse
Affiliation(s)
- Carlos Atico Ariza
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011, USA
| | | | | | | | | | | | | | | |
Collapse
|
34
|
Kane AJ, Sughrue ME, Rutkowski MJ, Tihan T, Parsa AT. The molecular pathology of central neurocytomas. J Clin Neurosci 2011; 18:1-6. [DOI: 10.1016/j.jocn.2010.06.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Accepted: 06/09/2010] [Indexed: 11/29/2022]
|
35
|
Wang X, Jiang X. PTEN: a default gate-keeping tumor suppressor with a versatile tail. Cell Res 2008; 18:807-16. [PMID: 18626510 DOI: 10.1038/cr.2008.83] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The tumor suppressor PTEN controls a variety of biological processes including cell proliferation, growth, migration, and death. As a master cellular regulator, PTEN itself is also subjected to deliberated regulation to ensure its proper function. Defects in PTEN regulation have a profound impact on carcinogenesis. In this review, we briefly discuss recent advances concerning PTEN regulation and how such knowledge facilitates our understanding and further exploration of PTEN biology. The carboxyl-tail of PTEN, which appears to be associated with multiple types of posttranslational regulation, will be under detailed scrutiny. Further, a comparative analysis of PTEN and p53 suggests while p53 needs to be activated to suppress tumorigenesis (a dormant gatekeeper), PTEN is probably a constitutive surveillant against cancer development, thus a default gatekeeper.
Collapse
Affiliation(s)
- Xinjiang Wang
- Cell Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | | |
Collapse
|
36
|
Rankin SL, Guy CS, Mearow KM. Neurite outgrowth is enhanced by laminin-mediated down-regulation of the low affinity neurotrophin receptor, p75NTR. J Neurochem 2008; 107:799-813. [PMID: 18786176 DOI: 10.1111/j.1471-4159.2008.05663.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Laminin (LN), an extracellular matrix component, is a key factor in promoting axonal regeneration, coordinately regulating growth in conjunction with trophic signals provided by the neurotrophins, including nerve growth factor (NGF). This study investigated potential interactions between the LN and NGF-mediated signaling pathways in PC12 cells and primary neurons. Neurite outgrowth stimulated by NGF was enhanced on a LN substrate. Western blot analysis of pertinent signal transduction components revealed both enhanced phosphorylation of early signaling intermediates upon co-stimulation, and a LN-induced down-regulation of p75NTR which could be prevented by the addition of integrin inhibitory arginine-glycine-aspartate (RGD) peptides. This p75NTR down-regulation was associated with a LN-mediated up-regulation of PTEN and resulted in a decrease in Rho activity. Studies using over-expression or siRNA-mediated knock-down of PTEN demonstrate a consistent inverse relationship with p75NTR, and the over-expression of p75NTR impaired neurite outgrowth on a LN substrate, as well as resulting in sustained activation of Rho which is inhibitory to neurite outgrowth. p75NTR is documented for its role in the transduction of inhibitory myelin-derived signals, and our results point to extracellular matrix regulation of p75NTR as a potential mechanism to ameliorate inhibitory signaling leading to optimized neurite outgrowth.
Collapse
Affiliation(s)
- Sherri L Rankin
- Division of BioMedical Sciences, Memorial University of Newfoundland, St John's, NL, Canada
| | | | | |
Collapse
|
37
|
Crucial role of the C-terminus of PTEN in antagonizing NEDD4-1-mediated PTEN ubiquitination and degradation. Biochem J 2008; 414:221-9. [PMID: 18498243 DOI: 10.1042/bj20080674] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PTEN (phosphatase and tensin homologue deleted on chromosome 10), a potent tumour suppressor and multifunctional signalling protein, is under intricate regulation. In the present study, we have investigated the mechanism and regulation of PTEN ubiquitination catalysed by NEDD4-1 (neural-precursor-cell-expressed, developmentally down-regulated 4-1), a ubiquitin ligase for PTEN we identified recently. Using the reconstituted assay and cellular analysis, we demonstrated that NEDD4-1-mediated PTEN ubiquitination depends on its intact HECT (homologous to E6-associated protein C-terminus) domain. Instead of using its WW domains (protein-protein interaction domains containing two conserved tryptophan residues) as a protein interaction module, NEDD4-1 interacts with PTEN through its N-terminal region containing a C2 domain as well as the HECT domain. Strikingly, we found that a C-terminal truncated PTEN fragment binds to NEDD4-1 with higher affinity than the full-length PTEN, suggesting an intrinsic inhibitory effect of the PTEN C-terminus on PTEN-NEDD4-1 interaction. Moreover, the C-terminal truncated PTEN is more sensitive to NEDD4-1-mediated ubiquitination and degradation. Therefore the present study reveals that the C-terminus of PTEN plays a critical role in stabilizing PTEN via antagonizing NEDD4-1-induced PTEN protein decay; conversely, truncation of the PTEN C-terminus results in rapid NEDD4-1-mediated PTEN degradation, a possible mechanism accounting for attenuation of PTEN function by certain PTEN mutations in human cancers.
Collapse
|
38
|
Abstract
Synapse formation requires contact between dendrites and axons. Although this process is often viewed as axon mediated, dendritic filopodia may be actively involved in mediating synaptogenic contact. Although the signaling cues underlying dendritic filopodial motility are mostly unknown, brain-derived neurotrophic factor (BDNF) increases the density of dendritic filopodia and conditional deletion of tyrosine receptor kinase B (TrkB) reduces synapse number in vivo. Here, we report that TrkB associates with dendritic growth cones and filopodia, mediates filopodial motility, and does so via the phosphoinositide 3 kinase (PI3K) pathway. We used genetic and pharmacological manipulations of mouse hippocampal neurons to assess signaling downstream of TrkB. Conditional knock-out of two downstream negative regulators of TrkB signaling, Pten (phosphatase with tensin homolog) and Nf1 (neurofibromatosis type 1), enhanced filopodial motility. This effect was PI3K-dependent and correlated with synaptic density. Phosphatidylinositol 3,4,5-trisphosphate (PIP3) was preferentially localized in filopodia and this distribution was enhanced by BDNF application. Thus, intracellular control of filopodial dynamics converged on PI3K activation and PIP3 accumulation, a cellular paradigm conserved for chemotaxis in other cell types. Our results suggest that filopodial movement is not random, but responsive to synaptic guidance molecules.
Collapse
|
39
|
Yang L, Wang S, Sung B, Lim G, Mao J. Morphine induces ubiquitin-proteasome activity and glutamate transporter degradation. J Biol Chem 2008; 283:21703-13. [PMID: 18539596 DOI: 10.1074/jbc.m800809200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glutamate transporters play a crucial role in physiological glutamate homeostasis, neurotoxicity, and glutamatergic regulation of opioid tolerance. However, how the glutamate transporter turnover is regulated remains poorly understood. Here we show that chronic morphine exposure induced posttranscriptional down-regulation of the glutamate transporter EAAC1 in C6 glioma cells with a concurrent decrease in glutamate uptake and increase in proteasome activity, which were blocked by the selective proteasome inhibitor MG-132 or lactacystin but not the lysosomal inhibitor chloroquin. At the cellular level, chronic morphine induced the PTEN (phosphatase and tensin homolog deleted on chromosome Ten)-mediated up-regulation of the ubiquitin E3 ligase Nedd4 via cAMP/protein kinase A signaling, leading to EAAC1 ubiquitination and proteasomal degradation. Either Nedd4 or PTEN knockdown with small interfering RNA prevented the morphine-induced EAAC1 degradation and decreased glutamate uptake. These data indicate that cAMP/protein kinase A signaling serves as an intracellular regulator upstream to the activation of the PTEN/Nedd4-mediated ubiquitin-proteasome system activity that is critical for glutamate transporter turnover. Under an in vivo condition, chronic morphine exposure also induced posttranscriptional down-regulation of the glutamate transporter EAAC1, which was prevented by MG-132, and transcriptional up-regulation of PTEN and Nedd4 within the spinal cord dorsal horn. Thus, inhibition of the ubiquitin-proteasome-mediated glutamate transporter degradation may be an important mechanism for preventing glutamate overexcitation and may offer a new strategy for treating certain neurological disorders and improving opioid therapy in chronic pain management.
Collapse
Affiliation(s)
- Liling Yang
- MGH Center for Translational Pain Research, Department of Anesthesia and Critical Care, Massachusetts General Hospital, Harvard Medical School, 75 Parkman Street, Boston, MA 02114, USA
| | | | | | | | | |
Collapse
|
40
|
Cook JL, Re RN, deHaro DL, Abadie JM, Peters M, Alam J. The trafficking protein GABARAP binds to and enhances plasma membrane expression and function of the angiotensin II type 1 receptor. Circ Res 2008; 102:1539-47. [PMID: 18497328 DOI: 10.1161/circresaha.108.176594] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Proteins that bind to the intracellular expanses, particularly cytoplasmic tail regions, of heptahelical integral membrane receptors are of particular interest in that they can mediate or modulate trafficking or intracellular signaling. In an effort to distinguish new proteins that might promote angiotensin II type 1 (AT(1)) receptor intracellular events, we screened a yeast 2-hybrid mouse brain library with the rat AT(1A) receptor (AT(1)R) carboxyl terminus and identified GABARAP, a protein involved in intracellular trafficking of the GABA(A) receptor, as a binding partner for the AT(1)R. Interaction of GABARAP with the AT(1)R carboxyl terminus was further substantiated using GST pull-down assays, and binding of the full-length tagged AT(1)R to GABARAP was verified using coimmunoprecipitation. Bioluminescence resonance energy transfer assays further confirmed specific interaction of GABARAP with AT(1)R. Moreover, GABARAP clearly increased the steady-state level of plasma membrane-associated AT(1)R in PC-12 cells. Cotransfection of GABARAP with an AT(1)R fluorescent fusion protein increased PC-12 cell surface expression of the AT(1)R more than 6-fold when standardized to the level of intracellular expression. Furthermore, GABARAP overexpression in CHO-K1 cells engineered to express AT(1)R increased angiotensin II binding sites 3.7-fold and angiotensin II-induced phospho-extracellular signal-regulated kinase 1/2 and cellular proliferation significantly over levels obtained with AT(1)R overexpression alone. In addition, small interfering RNA-mediated knockdown of GABARAP reduced the steady-state levels of the AT(1)R fluorescent fusion protein by 43% and its cell surface expression by 84%. Immunoblot analyses confirmed the quantitative image data. We conclude that GABARAP binds to and promotes trafficking of the AT(1)R to the plasma membrane.
Collapse
Affiliation(s)
- Julia L Cook
- Division of Research, Ochsner Clinic Foundation, Ochsner Health System, 1514 Jefferson Hwy, New Orleans, LA 70121, USA.
| | | | | | | | | | | |
Collapse
|
41
|
Neurotrophin-induced upregulation of p75NTR via a protein kinase C-delta-dependent mechanism. Brain Res 2008; 1217:10-24. [PMID: 18511024 DOI: 10.1016/j.brainres.2008.03.076] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Revised: 02/27/2008] [Accepted: 03/28/2008] [Indexed: 02/06/2023]
Abstract
Neurotrophins exert their biological effects via p75NTR and Trk receptors. Functional interplay between these two receptors has been widely explored with respect to p75NTR enhancing the activation and signalling of Trk, but few studies address the bidirectional aspects. We have previously demonstrated that the expression of p75NTR can be differentially modulated by different Trk receptor mutations. Here we investigate the mechanism of Nerve Growth Factor (NGF)-induced upregulation of p75NTR expression. We utilize pharmacological inhibition to investigate the role of various TrkA-associated signalling intermediates in this regulatory cascade. Notably, the inhibition of phospholipase C-gamma (PLC-gamma) using U73122, prevented the NGF-induced upregulation of p75NTR protein and mRNA. The inhibition of protein kinase C-delta (PKC-delta) activation by rottlerin, a selective PKC-delta inhibitor, and by small interfering RNA (siRNA) directed against PKC-delta also inhibited this NGF-induced upregulation. Finally, we also show that in cerebellar granule neurons, BDNF acting via TrkB increases p75NTR expression in a PKC-delta dependent manner. These results indicate the importance of Trk-dependent PLC-gamma and PKC-delta activation for downstream regulation of p75NTR protein expression in response to neurotrophin stimulation, a process that has implications to the survival and growth of the developing nervous system.
Collapse
|
42
|
Yuan Y, Gao X, Guo N, Zhang H, Xie Z, Jin M, Li B, Yu L, Jing N. rSac3, a novel Sac domain phosphoinositide phosphatase, promotes neurite outgrowth in PC12 cells. Cell Res 2008; 17:919-32. [PMID: 17909536 DOI: 10.1038/cr.2007.82] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Sac domain-containing proteins belong to a newly identified family of phosphoinositide phosphatases (the PIPPase family). Despite well-characterized enzymatic activity, the biological functions of this mammalian Sac domain PIPPase family remain largely unknown. We identified a novel Sac domain-containing protein, rat Sac3 (rSac3), which is widely expressed in various tissues and localized to the endoplasmic reticulum, Golgi complex and recycling endosomes. rSac3 displays PIPPase activity with PI(3)P, PI(4)P and PI(3,5)P(2) as substrates in vitro, and a mutation in the catalytic core of the Sac domain abolishes its enzymatic activity. The expression of rSac3 is upregulated during nerve growth factor (NGF)-stimulated PC12 cell neuronal differentiation, and overexpression of this protein promotes neurite outgrowth in PC12 cells. Conversely, inhibition of rSac3 expression by antisense oligonucleotides reduces neurite outgrowth of NGF-stimulated PC12 cells, and the active site mutation of rSac3 eliminates its neurite-outgrowth-promoting activity. These results indicate that rSac3 promotes neurite outgrowth in differentiating neurons through its PIPPase activity, suggesting that Sac domain PIPPase proteins may participate in forward membrane trafficking from the endoplasmic reticulum and Golgi complex to the plasma membrane, and may function as regulators of this crucial process of neuronal cell growth and differentiation.
Collapse
Affiliation(s)
- Yiyuan Yuan
- Laboratory of Molecular Cell Biology and Key Laboratory of Stem Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue yang Road, Shanghai 200031, China
| | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Li X, Peng C, Li L, Ming M, Yang D, Le W. Glial cell-derived neurotrophic factor protects against proteasome inhibition-induced dopamine neuron degeneration by suppression of endoplasmic reticulum stress and caspase-3 activation. J Gerontol A Biol Sci Med Sci 2007; 62:943-50. [PMID: 17895431 DOI: 10.1093/gerona/62.9.943] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Evidence has shown that ubiquitin proteasome system (UPS) impairment plays an important role in the dopamine (DA) neurodegeneration in Parkinson's disease (PD). It has been reported that application of proteasomal inhibitor lactacystin in ventral mesencephalon (VM) cultures can cause DA neurodegeneration, although the underlying mechanisms are not clear. Herein, we used the lactacystin-induced DA cell degeneration model to study the neuroprotection of glial cell-derived neurotrophic factor (GDNF) in VM cultures. We measured the expression of endoplasmic reticulum stress (ERS)-related genes, and determined the caspase-3 activation, apoptotic cell death, as well as alpha-synuclein-positive inclusions in DA neurons. We found that GDNF treatment significantly suppressed the expression of ERS-related genes and inhibited the activation of caspase-3 and apoptotic cell death without affecting alpha-synuclein-positive inclusions in DA neurons. Our study suggests that the protection of GDNF against DA neurodegeneration in the UPS impairment model is associated with ERS and caspase-3 suppression.
Collapse
Affiliation(s)
- Xuping Li
- Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences/Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | | | | | | | | | | |
Collapse
|
44
|
Samoylenko A, Byts N, Rajalingam K, von Ahsen N, Rapp UR, Ehrenreich H, Sirén AL. Thrombopoietin inhibits nerve growth factor-induced neuronal differentiation and ERK signalling. Cell Signal 2007; 20:154-62. [PMID: 18006272 DOI: 10.1016/j.cellsig.2007.10.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Revised: 09/03/2007] [Accepted: 10/03/2007] [Indexed: 11/30/2022]
Abstract
Thrombopoietin (TPO), a hematopoietic growth factor regulating platelet production, and its receptor (TPOR) were recently shown to be expressed in the brain where they exert proapoptotic activity. Here we used PC12 cells, an established model of neuronal differentiation, to investigate the effects of TPO on neuronal survival and differentiation. These cells expressed TPOR mRNA. TPO increased cell death in neuronally differentiated PC12 cells but had no effect in undifferentiated cells. Surprisingly, TPO inhibited nerve growth factor (NGF)-induced differentiation of PC12 cells in a dose- and time-dependent manner. This inhibition was dependent on the activity of Janus kinase-2 (JAK2). Using phospho-kinase arrays and Western blot we found downregulation of the NGF-stimulated phosphorylation of the extracellular signal-regulated kinase p42ERK by TPO with no effect on phosphorylation of Akt or stress kinases. NGF-induced phosphorylation of ERK-activating kinases, MEK1/2 and C-RAF was also reduced by TPO while NGF-induced RAS activation was not attenuated by TPO treatment. In contrast to its inhibitory effects on NGF signalling, TPO had no effect on epidermal growth factor (EGF)-stimulated ERK phosphorylation or proliferation of PC12 cells. Our data indicate that TPO via activation of its receptor-bound JAK2 delays the NGF-dependent acquisition of neuronal phenotype and decreases neuronal survival by suppressing NGF-induced ERK activity.
Collapse
Affiliation(s)
- Anatoly Samoylenko
- University of Würzburg, Section of Experimental Neurosurgery, Department of Neurosurgery, Josef-Schneider-St. 11, 97080 Würzburg, Germany
| | | | | | | | | | | | | |
Collapse
|
45
|
Huang CH, Cheng JC, Chen JC, Tseng CP. Evaluation of the role of Disabled-2 in nerve growth factor-mediated neurite outgrowth and cellular signalling. Cell Signal 2007; 19:1339-47. [PMID: 17317100 DOI: 10.1016/j.cellsig.2007.01.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2006] [Revised: 01/10/2007] [Accepted: 01/10/2007] [Indexed: 11/18/2022]
Abstract
Disabled-2 (DAB2) is an adapter protein that plays a key role in cell proliferation and differentiation. We reported here that DAB2 is expressed in various regions of rat central nervous system and is most abundant in the olfactory bulb. The up-regulation of DAB2 upon 5,7-dihydroxytryptamine-induced spinal cord lesion implicates that DAB2 may participate in the regulation of neuronal plasticity. To investigate DAB2 function in the regulation of neurite outgrowth, the rat p59 and p82 form of DAB2 was individually and stably expressed in the PC12 cells. Both p59 and p82 inhibited nerve growth factor (NGF)-induced neurite outgrowth concomitantly with a decrease in the expression of neuron-specific cytoskeleton protein beta-tubulin III. To unveil the molecular mechanism of DAB2 in NGF signaling, we found that RhoA-GTPase activity was up-regulated in DAB2 stable lines whereas the Ras/MAPK and PI3-kinase/Akt signaling was not affected. The inhibitory effect of DAB2 on NGF-mediated neurite outgrowth was reversed by the pretreatment of Rho-kinase (ROCK) inhibitor Y27632, implicating that DAB2 modulates RhoA/ROCK signaling. Together, this study defines a role of DAB2 in the control of neuronal plasticity and demonstrates for the first time that DAB2 is a negative regulator in NGF-mediated neurite outgrowth.
Collapse
Affiliation(s)
- Ching-Hui Huang
- Graduate Institute of Basic Medical Sciences, Chang Gung University, Taoyuan 333, Taiwan, Republic of China
| | | | | | | |
Collapse
|
46
|
Vivanco I, Palaskas N, Tran C, Finn SP, Getz G, Kennedy NJ, Jiao J, Rose J, Xie W, Loda M, Golub T, Mellinghoff IK, Davis RJ, Wu H, Sawyers CL. Identification of the JNK signaling pathway as a functional target of the tumor suppressor PTEN. Cancer Cell 2007; 11:555-69. [PMID: 17560336 DOI: 10.1016/j.ccr.2007.04.021] [Citation(s) in RCA: 199] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2006] [Revised: 02/14/2007] [Accepted: 04/30/2007] [Indexed: 11/30/2022]
Abstract
Although most oncogenic phenotypes of PTEN loss are attributed to AKT activation, AKT alone is not sufficient to induce all of the biological activities associated with PTEN inactivation. We searched for additional PTEN-regulated pathways through gene set enrichment analysis (GSEA) and identified genes associated with JNK activation. PTEN null cells exhibit higher JNK activity, and genetic studies demonstrate that JNK functions parallel to and independently of AKT. Furthermore, PTEN deficiency sensitizes cells to JNK inhibition and negative feedback regulation of PI3K was impaired in PTEN null cells. Akt and JNK activation are highly correlated in human prostate cancer. These findings implicate JNK in PI3K-driven cancers and demonstrate the utility of GSEA to identify functional pathways using genetically defined systems.
Collapse
Affiliation(s)
- Igor Vivanco
- Molecular Biology Institute, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Aoki K, Nakamura T, Inoue T, Meyer T, Matsuda M. An essential role for the SHIP2-dependent negative feedback loop in neuritogenesis of nerve growth factor-stimulated PC12 cells. ACTA ACUST UNITED AC 2007; 177:817-27. [PMID: 17535963 PMCID: PMC2064282 DOI: 10.1083/jcb.200609017] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The local accumulation of phosphatidylinositol (3,4,5) trisphosphate (PIP(3)) and resulting activation of Rac1/Cdc42 play a critical role in nerve growth factor (NGF)-induced neurite outgrowth. To further explore the mechanism, we visualized PIP(3), phosphatidylinositol (3,4) bisphosphate, and Rac1/Cdc42 activities by fluorescence resonance energy transfer (FRET) imaging in NGF-stimulated PC12 cells. Based on the obtained FRET images, and with the help of in silico kinetic reaction model, we predicted that PI-5-phosphatase negatively regulates PIP(3) upon NGF stimulation. In agreement with this model, depletion of Src homology 2 domain-containing inositol polyphosphate 5-phosphatase 2 (SHIP2) markedly potentiated NGF-induced Rac1/Cdc42 activation and PIP(3) accumulation and considerably increased the number and the length of neurites in phosphate and tensin homologue-depleted PC12 cells. Further refinement of the computational model predicted Rac1 regulation of PI3-kinase and SHIP2, which was also validated experimentally. We propose that the SHIP2-mediated negative feedback on PIP(3) coordinately works with the PI3-kinase-mediated positive feedback to form an initial protrusive pattern and, later, to punctuate the PIP(3) accumulation to maintain proper neurite outgrowth.
Collapse
Affiliation(s)
- Kazuhiro Aoki
- Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | | | | | | | | |
Collapse
|
48
|
Korshunov A, Sycheva R, Golanov A. Recurrent cytogenetic aberrations in central neurocytomas and their biological relevance. Acta Neuropathol 2007; 113:303-12. [PMID: 17123091 DOI: 10.1007/s00401-006-0168-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2006] [Revised: 10/26/2006] [Accepted: 10/30/2006] [Indexed: 10/23/2022]
Abstract
Central neurocytomas are rare central nervous system neoplasms. Since the first description, approximately 500 cases of these tumors have been published to date. Nevertheless, only a limited number of genetic studies on these tumors have been reported. Here we investigated 20 "typical" central neurocytomas using array-based comparative genomic hybridization (array-CGH) with the GenoSensor Array 300. The functional significance of detected chromosomal aberrations harboring potent candidate genes was also examined at the mRNA expression level. Each tumor examined displayed DNA copy-number aberrations (CNAs), and mean number of CNAs per tumor was 38.1 +/- 7.1 (range 19-53). Frequent gains were mapped at 2p24.1-22.1, 10q23.3-26.3, 11q23-25, and 18q21.3-qter. Frequent losses were identified at 1pter-36.3, 1p34.3, 6q13-21, 12q23-qter, 17p13.3, 17q11-23, and 20pter-12.3. There were 10 gained and 23 lost single DNA clones affecting >or=40% of samples tested. mRNA expression levels of 24 selected candidate genes harbored in these imbalanced clones were analyzed. MYCN, PTEN, and OR5BF1 were strongly overexpressed, whereas BIN1, SNRPN, and HRAS were found to be strongly underrepresented at the transcriptional level. Thus these data support that MYCN oncogene gain/overexpression accompanied by reduced expression of BIN1 tumor suppressor may contribute to central neurocytoma tumorigenesis.
Collapse
Affiliation(s)
- Andrey Korshunov
- Department of Neuropathology, NN Burdenko Neurosurgical Institute, Fadeeva Str. 5, Moscow, 125047, Russia.
| | | | | |
Collapse
|
49
|
Bouwman J, Spijker S, Schut D, Wächtler B, Ylstra B, Smit AB, Verhage M. Reduced expression of neuropeptide genes in a genome-wide screen of a secretion-deficient mouse. J Neurochem 2006; 99:84-96. [PMID: 16987237 DOI: 10.1111/j.1471-4159.2006.04041.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Activity-dependent changes in synapses rely on functional changes in resident proteins and on gene expression. We addressed the relationship between synapse activity and the expression of synaptic genes by comparing RNA levels in the neocortex of normal mice versus secretion-deficient and therefore synaptically silent munc18-1 (mammalian homologue of Caenorhabditis elegans uncoordinated locomotion-18) null mutants, using microarray expression analysis, real-time quantitative PCR and northern blotting. We hypothesized that genes under the control of synaptic activity would be differentially expressed between mutants and controls. We found that few synaptic genes were differentially expressed. However, most neuropeptide genes with detectable expression on the microarray were differentially expressed, being expressed 3-20-fold higher in control cortex. Several other secreted proteins were also differentially expressed, but genes encoding their receptors and many other synaptic components were not. Differential expression was confirmed by real-time quantitative PCR analysis. In situ hybridization indicated that the difference in neuropeptide expression was uniform and not due to the loss of specific cells in the mutant. In primary sensory neurons, which do not depend on synaptic activity for their input, the differential expression of neuropeptides was not observed. These data argue against a general relationship between the activity of synapses and the expression of their resident proteins, but suggest a link between secretion and the expression of genes encoding the secreted products.
Collapse
Affiliation(s)
- J Bouwman
- Department of Functional Genomics, Centre for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit Amsterdam (VUA) and VU Medical Centre (VUmc), Amsterdam, the Netherlands
| | | | | | | | | | | | | |
Collapse
|
50
|
Otaegi G, Yusta-Boyo MJ, Vergaño-Vera E, Méndez-Gómez HR, Carrera AC, Abad JL, González M, de la Rosa EJ, Vicario-Abejón C, de Pablo F. Modulation of the PI 3-kinase-Akt signalling pathway by IGF-I and PTEN regulates the differentiation of neural stem/precursor cells. J Cell Sci 2006; 119:2739-48. [PMID: 16787946 DOI: 10.1242/jcs.03012] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Neural stem cells depend on insulin-like growth factor I (IGF-I) for differentiation. We analysed how activation and inhibition of the PI 3-kinase-Akt signalling affects the number and differentiation of mouse olfactory bulb stem cells (OBSCs). Stimulation of the pathway with insulin and/or IGF-I, led to an increase in Akt phosphorylated on residues Ser473 and Thr308 (P-Akt(Ser473) and P-Akt(Thr308), respectively) in proliferating OBSCs, and in differentiating cells. Conversely, P-Akt(Ser473) levels decreased by 50% in the OB of embryonic day 16.5-18.5 IGF-I knockout mouse embryos. Overexpression of PTEN, a negative regulator of the PI 3-kinase pathway, caused a reduction in the basal levels of P-Akt(Ser473) and P-Akt(Thr308) and a minor reduction in IGF-I-stimulated P-Akt(Ser473). Although PTEN overexpression decreased the proportion of neurons and astrocytes in the absence of insulin/IGF-I, it did not alter the proliferation or survival of OBSCs. Accordingly, overexpression of a catalytically inactive PTEN mutant promoted OBSCs differentiation. Inhibition of PI 3-kinase by LY294002 produced strong and moderate reductions in IGF-I-stimulated P-Akt(Ser473) and P-Akt(Thr308), respectively. Consequently, LY294002 reduced the proliferation of OBSCs and the number of neurons and astrocytes, and also augmented cell death. These findings indicate that OBSC differentiation is more sensitive to lower basal levels of P-Akt than proliferation or death. By regulating P-Akt levels in opposite ways, IGF-I and PTEN contribute to the fine control of neurogenesis in the olfactory bulb.
Collapse
Affiliation(s)
- Gaizka Otaegi
- Group of Growth Factors in Vertebrate Development, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), Ramiro de Maeztu 9, Madrid 28040, Spain
| | | | | | | | | | | | | | | | | | | |
Collapse
|