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Zong Y, Dai Y, Yan J, Yu B, Wang D, Mao S. The roles of circular RNAs in nerve injury and repair. Front Mol Neurosci 2024; 17:1419520. [PMID: 39077756 PMCID: PMC11284605 DOI: 10.3389/fnmol.2024.1419520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Accepted: 06/21/2024] [Indexed: 07/31/2024] Open
Abstract
Nerve injuries significantly impact the quality of life for patients, with severe cases posing life-threatening risks. A comprehensive understanding of the pathophysiological mechanisms underlying nerve injury is crucial to the development of effective strategies to promote nerve regeneration. Circular RNAs (circRNAs), a recently characterized class of RNAs distinguished by their covalently closed-loop structures, have been shown to play an important role in various biological processes. Numerous studies have highlighted the pivotal role of circRNAs in nerve regeneration, identifying them as potential therapeutic targets. This review aims to succinctly outline the latest advances in the role of circRNAs related to nerve injury repair and the underlying mechanisms, including peripheral nerve injury, traumatic brain injury, spinal cord injury, and neuropathic pain. Finally, we discuss the potential applications of circRNAs in drug development and consider the potential directions for future research in this field to provide insights into circRNAs in nerve injury repair.
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Affiliation(s)
| | | | | | | | - Dong Wang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, School of Medicine, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Susu Mao
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, School of Medicine, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
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2
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Zhang J, Yang SG, Zhou FQ. Glycogen synthase kinase 3 signaling in neural regeneration in vivo. J Mol Cell Biol 2024; 15:mjad075. [PMID: 38059848 PMCID: PMC11063957 DOI: 10.1093/jmcb/mjad075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 11/14/2023] [Accepted: 11/28/2023] [Indexed: 12/08/2023] Open
Abstract
Glycogen synthase kinase 3 (GSK3) signaling plays important and broad roles in regulating neural development in vitro and in vivo. Here, we reviewed recent findings of GSK3-regulated axon regeneration in vivo in both the peripheral and central nervous systems and discussed a few controversial findings in the field. Overall, current evidence indicates that GSK3β signaling serves as an important downstream mediator of the PI3K-AKT pathway to regulate axon regeneration in parallel with the mTORC1 pathway. Specifically, the mTORC1 pathway supports axon regeneration mainly through its role in regulating cap-dependent protein translation, whereas GSK3β signaling might be involved in regulating N6-methyladenosine mRNA methylation-mediated, cap-independent protein translation. In addition, GSK3 signaling also plays a key role in reshaping the neuronal transcriptomic landscape during neural regeneration. Finally, we proposed some research directions to further elucidate the molecular mechanisms underlying the regulatory function of GSK3 signaling and discover novel GSK3 signaling-related therapeutic targets. Together, we hope to provide an updated and insightful overview of how GSK3 signaling regulates neural regeneration in vivo.
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Affiliation(s)
- Jing Zhang
- Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, China
| | - Shu-Guang Yang
- Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, China
| | - Feng-Quan Zhou
- Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, China
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3
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Lamb WDB, Eastlake K, Luis J, Sharif NA, Khaw PT, Limb GA. MicroRNA profile of extracellular vesicles released by Müller glial cells. Front Cell Neurosci 2024; 17:1325114. [PMID: 38303973 PMCID: PMC10832456 DOI: 10.3389/fncel.2023.1325114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 12/15/2023] [Indexed: 02/03/2024] Open
Abstract
Introduction As with any other radial glia in the central nervous system, Müller glia derive from the same neuroepithelial precursors, perform similar functions, and exhibit neurogenic properties as radial glia in the brain. Müller glial cells retain progenitor-like characteristics in the adult human eye and can partially restore visual function upon intravitreal transplantation into animal models of glaucoma. Recently, it has been demonstrated that intracellular communication is possible via the secretion of nano-sized membrane-bound extracellular vesicles (EV), which contain bioactive molecules like microRNA (miRNA) and proteins that induce phenotypic changes when internalised by recipient cells. Methods We conducted high-throughput sequencing to profile the microRNA signature of EV populations secreted by Müller glia in culture and used bioinformatics tools to evaluate their potential role in the neuroprotective signalling attributed to these cells. Results Sequencing of miRNA within Müller EV suggested enrichment with species associated with stem cells such as miR-21 and miR-16, as well as with miRNA previously found to play a role in diverse Müller cell functions in the retina: miR-9, miR-125b, and the let-7 family. A total of 51 miRNAs were found to be differentially enriched in EV compared to the whole cells from which EV originated. Bioinformatics analyses also indicated that preferential enrichment of species was demonstrated to regulate genes involved in cell proliferation and survival, including PTEN, the master inhibitor of the PI3K/AKT pathway. Discussion The results suggest that the release by Müller cells of miRNA-enriched EV abundant in species that regulate anti-apoptotic signalling networks is likely to represent a significant proportion of the neuroprotective effect observed after the transplantation of these cells into animal models of retinal ganglion cell (RGC) depletion. Future studies will seek to evaluate the modulation of putative genes as well as the activation of these pathways in in vitro and in vivo models following the internalisation of Müller-EV by target retinal neurons.
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Affiliation(s)
- William D. B. Lamb
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
| | - Karen Eastlake
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
| | - Joshua Luis
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
| | - Najam A. Sharif
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
- Department of Global Alliances and Collaboration, Global Ophthalmology Research and Development, Santen Inc., Emeryville, CA, United States
| | - Peng T. Khaw
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
| | - G. Astrid Limb
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
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4
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Hassan SSU, Samanta S, Dash R, Karpiński TM, Habibi E, Sadiq A, Ahmadi A, Bungau S. The neuroprotective effects of fisetin, a natural flavonoid in neurodegenerative diseases: Focus on the role of oxidative stress. Front Pharmacol 2022; 13:1015835. [PMID: 36299900 PMCID: PMC9589363 DOI: 10.3389/fphar.2022.1015835] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 09/08/2022] [Indexed: 12/13/2022] Open
Abstract
Oxidative stress (OS) disrupts the chemical integrity of macromolecules and increases the risk of neurodegenerative diseases. Fisetin is a flavonoid that exhibits potent antioxidant properties and protects the cells against OS. We have viewed the NCBI database, PubMed, Science Direct (Elsevier), Springer-Nature, ResearchGate, and Google Scholar databases to search and collect relevant articles during the preparation of this review. The search keywords are OS, neurodegenerative diseases, fisetin, etc. High level of ROS in the brain tissue decreases ATP levels, and mitochondrial membrane potential and induces lipid peroxidation, chronic inflammation, DNA damage, and apoptosis. The subsequent results are various neuronal diseases. Fisetin is a polyphenolic compound, commonly present in dietary ingredients. The antioxidant properties of this flavonoid diminish oxidative stress, ROS production, neurotoxicity, neuro-inflammation, and neurological disorders. Moreover, it maintains the redox profiles, and mitochondrial functions and inhibits NO production. At the molecular level, fisetin regulates the activity of PI3K/Akt, Nrf2, NF-κB, protein kinase C, and MAPK pathways to prevent OS, inflammatory response, and cytotoxicity. The antioxidant properties of fisetin protect the neural cells from inflammation and apoptotic degeneration. Thus, it can be used in the prevention of neurodegenerative disorders.
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Affiliation(s)
- Syed Shams ul Hassan
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
- Department of Natural Product Chemistry, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Saptadip Samanta
- Department of Physiology, Midnapore College, Midnapore, West Bengal, India
| | - Raju Dash
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju, South Korea
| | - Tomasz M. Karpiński
- Department of Medical Microbiology, Poznań University of Medical Sciences, Poznań, Poland
| | - Emran Habibi
- Department of Pharmacognosy, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Abdul Sadiq
- Department of Pharmacy, University of Malakand, Chakdara, Pakistan
| | - Amirhossein Ahmadi
- Pharmaceutical Sciences Research Centre, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Simona Bungau
- Department of Pharmacy, Faculty of Medicine and Pharmacy, University of Oradea, Oradea, Romania
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5
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Wei SW, Zou MM, Huan J, Li D, Zhang PF, Lu MH, Xiong J, Ma YX. Role of the hydrogen sulfide-releasing donor ADT-OH in the regulation of mammal neural precursor cells. J Cell Physiol 2022; 237:2877-2887. [PMID: 35342944 DOI: 10.1002/jcp.30726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 03/05/2022] [Accepted: 03/09/2022] [Indexed: 11/06/2022]
Abstract
Neural precursor cells (NPCs) generate new neurons to supplement neuronal loss as well as to repair damaged neural circuits. Therefore, NPCs have potential applications in a variety of neurological diseases, such as spinal cord injury, traumatic brain injury, and glaucoma. Specifically, improving NPCs proliferation and manipulating their differentiated cell types can be a beneficial therapy for a variety of these diseases. ADT-OH is a slow-releasing organic H2 S donor that produces a slow and continuous release of H2 S to maintain normal brain functions. In this study, we aimed to explore the effect of ADT-OH on NPCs. Our results demonstrated that ADT-OH promotes self-renewal and antiapoptosis ability of cultured NPCs. Additionally, it facilitates more NPCs to differentiate into neurons and oligodendrocytes, while inhibiting their differentiation into astrocytes. Furthermore, it enhances axonal growth. Moreover, we discovered that the mRNA and protein expression of β-catenin, TCF7L2, c-Myc, Ngn1, and Ngn2, which are key genes that regulate NPCs self-renewal and differentiation, were increased in the presence of ADT-OH. Altogether, these results indicate that ADT-OH may be a promising drug to regulate the neurogenesis of NPCs, and needs to be studied in the future for clinical application potential.
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Affiliation(s)
- Shan-Wen Wei
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, Suzhou, China
| | - Ming-Ming Zou
- Department of Neurosurgery, First Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Jian Huan
- Department of Radiation Oncology, The Affiliated Suzhou Science & Technology Town Hospital of Nanjing Medical University, Suzhou, China
| | - Di Li
- Department of Rehabilitation, The Affiliated Zhangjiagang Hospital of Soochow University, Suzhou, China
| | - Peng-Fei Zhang
- Department of Neurosurgery, First Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Mei-Hong Lu
- School of Medical Technology, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Jian Xiong
- Department of Rehabilitation, The Affiliated Zhangjiagang Hospital of Soochow University, Suzhou, China
| | - Yan-Xia Ma
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, Suzhou, China
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6
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Calvo B, Thornton TM, Rincon M, Tranque P, Fernandez M. Regulation of GSK3β by Ser 389 Phosphorylation During Neural Development. Mol Neurobiol 2021; 58:809-820. [PMID: 33029741 DOI: 10.1007/s12035-020-02147-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 09/22/2020] [Indexed: 10/23/2022]
Abstract
GSK3β is a constitutively active kinase that promotes cell death, which requires strict regulatory mechanisms. Although Akt-mediated phosphorylation at Ser9 is the default mechanism to inactivate GSK3β, phosphorylation of GSK3β at Ser389 by p38 MAPK has emerged as an alternative inhibitory pathway that provides cell protection and repair in response to DNA damage. Phosphorylation of Ser389 GSK3β has been detected in adult brain, where it has been related to neuronal survival and behavior. However, the use of this pathway to regulate GSK3β in the neonatal developing brain is unknown. In this study, we show that phosphorylation of GSK3β at Ser389 in the brain is developmentally regulated, with the highest levels corresponding to the first 2 weeks of age. Moreover, we found that the phosphorylation of GSK3β at Ser389 is the preferential mechanism for inactivating brain GSK3β in 2-week-old mice. Importantly, we show that phospho-Ser389 GSK3β expression is predominant in neuronal cell cultures from neonatal brain relative to other cell populations. However, phospho-Ser389 GSK3β is triggered by DNA double-strand breaks in all developing neural cell types examined. Thus, the phosphorylation of GSK3β on Ser389 could be a central regulatory mechanism to restrain GSK3β during neurogenesis early in life.
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Affiliation(s)
- Belen Calvo
- Research Institute for Neurological Disabilities (IDINE), Medical School, University of Castilla-La Mancha, 02006, Albacete, Spain
| | - Tina M Thornton
- Department of Medicine, Immunobiology Division, University of Vermont, Burlington, VT, 05405, USA
| | - Mercedes Rincon
- Department of Medicine, Immunobiology Division, University of Vermont, Burlington, VT, 05405, USA
- Department of Immunology and Microbiology, University of Colorado Denver, Aurora, CO, USA
| | - Pedro Tranque
- Research Institute for Neurological Disabilities (IDINE), Medical School, University of Castilla-La Mancha, 02006, Albacete, Spain
| | - Miriam Fernandez
- Research Institute for Neurological Disabilities (IDINE), Medical School, University of Castilla-La Mancha, 02006, Albacete, Spain.
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7
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Savvaki M, Kafetzis G, Kaplanis SI, Ktena N, Theodorakis K, Karagogeos D. Neuronal, but not glial, Contactin 2 negatively regulates axon regeneration in the injured adult optic nerve. Eur J Neurosci 2021; 53:1705-1721. [PMID: 33469963 DOI: 10.1111/ejn.15121] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 12/26/2020] [Accepted: 01/17/2021] [Indexed: 01/09/2023]
Abstract
Mammalian adult neurons of the central nervous system (CNS) display limited ability to regrow axons after trauma. The developmental decline in their regenerative ability has been attributed to both intrinsic and extrinsic factors, including postnatal suppression of transcription factors and non-neuronal inhibitory components, respectively. The cell adhesion molecule Contactin 2 (CNTN2) is expressed in neurons and oligodendrocytes in the CNS. Neuronal CNTN2 is highly regulated during development and plays critical roles in axon growth and guidance and neuronal migration. On the other hand, CNTN2 expressed by oligodendrocytes interferes with the myelination process, with its ablation resulting in hypomyelination. In the current study, we investigate the role of CNTN2 in neuronal survival and axon regeneration after trauma, in the murine optic nerve crush (ONC) model. We unveil distinct roles for neuronal and glial CNTN2 in regenerative responses. Surprisingly, our data show a conflicting role of neuronal and glial CNTN2 in axon regeneration. Although glial CNTN2 as well as hypomyelination are dispensable for both neuronal survival and axon regeneration following ONC, the neuronal counterpart comprises a negative regulator of regeneration. Specifically, we reveal a novel mechanism of action for neuronal CNTN2, implicating the inhibition of Akt signalling pathway. The in vitro analysis indicates a BDNF-independent mode of action and biochemical data suggest the implication of the truncated form of TrkB neurotrophin receptor. In conclusion, CNTN2 expressed in CNS neurons serves as an inhibitor of axon regeneration after trauma and its mechanism of action involves the neutralization of Akt-mediated neuroprotective effects.
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Affiliation(s)
- Maria Savvaki
- Department of Basic Science, Faculty of Medicine, University of Crete, Crete, Greece.,Institute of Molecular Biology & Biotechnology - FoRTH, Heraklion, Crete, Greece
| | - George Kafetzis
- Department of Biology, University of Crete, Crete, Greece.,School of Life Sciences, University of Sussex, Brighton, UK
| | - Stefanos-Ioannis Kaplanis
- Department of Basic Science, Faculty of Medicine, University of Crete, Crete, Greece.,Institute of Molecular Biology & Biotechnology - FoRTH, Heraklion, Crete, Greece
| | - Niki Ktena
- Department of Basic Science, Faculty of Medicine, University of Crete, Crete, Greece.,Institute of Molecular Biology & Biotechnology - FoRTH, Heraklion, Crete, Greece
| | - Kostas Theodorakis
- Institute of Molecular Biology & Biotechnology - FoRTH, Heraklion, Crete, Greece
| | - Domna Karagogeos
- Department of Basic Science, Faculty of Medicine, University of Crete, Crete, Greece.,Institute of Molecular Biology & Biotechnology - FoRTH, Heraklion, Crete, Greece
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8
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Liu C, Liu J, Liu C, Zhou Q, Zhou Y, Zhang B, Saijilafu. The intrinsic axon regenerative properties of mature neurons after injury. Acta Biochim Biophys Sin (Shanghai) 2021; 53:1-9. [PMID: 33258872 DOI: 10.1093/abbs/gmaa148] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Indexed: 01/07/2023] Open
Abstract
Thousands of nerve injuries occur in the world each year. Axon regeneration is a very critical process for the restoration of the injured nervous system's function. However, the precise molecular mechanism or signaling cascades that control axon regeneration are not clearly understood, especially in mammals. Therefore, there is almost no ideal treatment method to repair the nervous system's injury until now. Mammalian axonal regeneration requires multiple signaling pathways to coordinately regulate gene expression in soma and assembly of the cytoskeleton protein in the growth cone. A better understanding of their molecular mechanisms, such as axon regeneration regulatory signaling cascades, will be helpful in developing new treatment strategies for promoting axon regeneration. In this review, we mainly focus on describing these regeneration-associated signaling cascades, which regulate axon regeneration.
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Affiliation(s)
- Chunfeng Liu
- Department of Orthopedic Surgery, Suzhou Kowloon Hospital, Shanghai Jiaotong University Medical School, Suzhou 215000, China
| | - Jinlian Liu
- Department of Orthopedic Surgery, Suzhou Kowloon Hospital, Shanghai Jiaotong University Medical School, Suzhou 215000, China
| | - Chaoqun Liu
- Department of Orthopedic Surgery, Suzhou Kowloon Hospital, Shanghai Jiaotong University Medical School, Suzhou 215000, China
| | - Qing Zhou
- Department of Orthopedic Surgery, Suzhou Kowloon Hospital, Shanghai Jiaotong University Medical School, Suzhou 215000, China
| | - Yaodong Zhou
- Department of Orthopedic Surgery, Suzhou Kowloon Hospital, Shanghai Jiaotong University Medical School, Suzhou 215000, China
| | - Boyin Zhang
- Orthopedics Surgery Department, China-Japan Union Hospital of Jilin University, Changchun 130033, China
| | - Saijilafu
- Department of Orthopaedics, The First Affiliated Hospital, Orthopaedic Institute, Soochow University, Suzhou 215007, China
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9
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Matsumoto T, Chino H, Akiya M, Hashimura M, Yokoi A, Tochimoto M, Nakagawa M, Jiang Z, Saegusa M. Requirements of LEFTY and Nodal overexpression for tumor cell survival under hypoxia in glioblastoma. Mol Carcinog 2020; 59:1409-1419. [PMID: 33111989 DOI: 10.1002/mc.23265] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 10/07/2020] [Accepted: 10/13/2020] [Indexed: 01/06/2023]
Abstract
Glioblastomas (GBM) contain numerous hypoxic foci associated with a rare fraction of glioma stem cells (GSCs). Left-right determination factor (LEFTY) and Nodal, members of the transforming growth factor β (TGF-β) superfamily, have glycogen synthase kinase 3β (GSK-3β) phosphorylation motifs and are linked with stemness in human malignancies. Herein, we investigated the roles of LEFTY and Nodal in GBM hypoxic foci. In clinical samples, significantly higher expression of LEFTY, Nodal, phospho (p) GSK-3β, pSmad2, and Nestin, as well as higher apoptotic and lower proliferation rates, were observed in nonpseudopalisading (non-Ps) perinecrotic lesions as compared to Ps and non-necrotic tumor lesions, with a positive correlation between LEFTY, Nodal, pGSK-3β, or pSmad2 scores. In KS-1, a GBM cell line that lacks endogenous Nodal expression, treatment with the hypoxic mimetic CoCl2 increased LEFTY, pGSK-3β, and pSmad2 levels, but decreased pAkt levels. Moreover, the promoter for LEFTY, but not Nodal, was activated by Smad2 or TGF-β1, suggesting that overexpression of LEFTY and Nodal may be due to Akt-independent GSK-3β inactivation, with or without cooperation of the TGF-β1/Smad2 axis. LEFTY and Nodal overexpression increased proliferation rates and reduced susceptibility to CoCl2 -induced apoptosis, and increased the expression of epithelial-mesenchymal transition (EMT)/GSC-related markers. An increased ALDH1high population and more efficient spheroid formation was also observed in LEFTY-overexpressing cells. These findings suggest that LEFTY and Nodal may contribute to cell survival in non-Ps GBM perinecrotic lesions, leading to alterations in apoptosis, proliferation, or EMT/GCS features.
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Affiliation(s)
- Toshihide Matsumoto
- Department of Pathology, Kitasato University School of Medicine, Kanagawa, Japan
| | - Hiromi Chino
- Department of Pathology, Kitasato University School of Medicine, Kanagawa, Japan
| | - Masashi Akiya
- Department of Pathology, Kitasato University School of Medicine, Kanagawa, Japan
| | - Miki Hashimura
- Department of Pathology, Kitasato University School of Medicine, Kanagawa, Japan
| | - Ako Yokoi
- Department of Pathology, Kitasato University School of Medicine, Kanagawa, Japan
| | - Masataka Tochimoto
- Department of Pathology, Kitasato University School of Medicine, Kanagawa, Japan
| | - Mayu Nakagawa
- Department of Pathology, Kitasato University School of Medicine, Kanagawa, Japan
| | - Zesong Jiang
- Department of Pathology, Kitasato University School of Medicine, Kanagawa, Japan
| | - Makoto Saegusa
- Department of Pathology, Kitasato University School of Medicine, Kanagawa, Japan
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10
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Qian C, Zhou FQ. Updates and challenges of axon regeneration in the mammalian central nervous system. J Mol Cell Biol 2020; 12:798-806. [PMID: 32470988 PMCID: PMC7816684 DOI: 10.1093/jmcb/mjaa026] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 05/01/2020] [Accepted: 05/26/2020] [Indexed: 02/07/2023] Open
Abstract
Axon regeneration in the mammalian central nervous system (CNS) has been a long-standing and highly challenging issue. Successful CNS axon regeneration will benefit many human diseases involving axonal damage, such as spinal cord injury, traumatic brain injury, glaucoma, and neurodegenerative diseases. The current consensus is that the diminished intrinsic regenerative ability in mature CNS neurons and the presence of extrinsic inhibitors blocking axon regrowth are two major barriers for axon regeneration. During the past decade, studies targeting the intrinsic axon growth ability via regulation of gene transcription have produced very promising results in optic nerve and/or spinal cord regeneration. Manipulations of various signaling pathways or the nuclear transcription factors directly have been shown to sufficiently drive CNS axon regrowth. Converging evidence reveals that some pro-regenerative transcriptomic states, which are commonly accomplished by more comprehensive epigenetic regulations, exist to orchestrate the complex tasks of injury sensing and axon regeneration. Moreover, genetic reprogramming achieved via transcriptome and epigenome modifications provides novel mechanisms for enhancing axon regeneration. Recent studies also highlighted the important roles of remodeling neuronal cytoskeleton in overcoming the extrinsic inhibitory cues. However, our knowledge about the cellular and molecular mechanisms by which neurons regulate their intrinsic axon regeneration ability and response to extrinsic inhibitory cues is still fragmented. Here, we provide an update about recent research progress in axon regeneration and discuss major remaining challenges for long-distance axon regeneration and the subsequent functional recovery.
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Affiliation(s)
- Cheng Qian
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Feng-Quan Zhou
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.,The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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11
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Khandelwal M, Manglani K, Gupta S, Tiku AB. Gamma radiation improves AD pathogenesis in APP/PS1 mouse model by potentiating insulin sensitivity. Heliyon 2020; 6:e04499. [PMID: 32775714 PMCID: PMC7399127 DOI: 10.1016/j.heliyon.2020.e04499] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 04/23/2020] [Accepted: 07/15/2020] [Indexed: 11/30/2022] Open
Abstract
Alzheimer's disease (AD) is the largest unmet medical complication. The devastation caused by the disease can be assumed from the disease symptoms like speech impairment, loss of self-awareness, acute memory loss etc. The individuals suffering from AD completely depend on caregivers and have to bear the high cost of treatment which increases the socio-economic burden on the society. Recent studies have shown that radiation exposure can have therapeutic effects when given in suitable amount for a specific time period. Therefore, we investigated the role of gamma irradiation in AD pathogenesis. The effect of radiation on amelioration of disease progression was studied in AD transgenic mice model (APP/PS1). Our in-vivo studies using APP/PS1 mice demonstrated that a single dose of 4.0 Gy gamma irradiation improves AD associated behavioral impairment. Radiation exposure also increased the level of anti-oxidant enzymes and reduced the astrocyte activation in the brain of APP/PS1 mice. A significant reduction was observed in AD associated proteins (APP, pTau, BACE) and neurofibrillary tangle formations (NFTs). Exposure to a single dose of 4 Gy gamma radiation also increased glucose metabolic functionality in AD transgenic mouse model. The kinases involved in insulin signaling such as GSK, ERK and JNK were also found to be modulated. However, an increased level of GSK3β (ser 9) was observed, which could be responsible for downregulating ERK and JNK phosphorylation. This resulted in a decrease in neurofibrillary tangle formations and amyloid deposition. The reduced hyperphosphorylation of Tau can be attributed to the increased level of GSK3β (ser 9) downregulating ERK and JNK phosphorylation. Thus, a single dose of 4 Gy gamma irradiation was found to have therapeutic benefits in treating AD via potentiating insulin signaling in APP/PS1 transgenic mice.
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Affiliation(s)
- Mayuri Khandelwal
- Molecular Science Laboratory, National Institute of Immunology, New Delhi, 110067, India.,Radiation and Cancer Therapeutics Lab, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Kapil Manglani
- Molecular Science Laboratory, National Institute of Immunology, New Delhi, 110067, India
| | - Sarika Gupta
- Molecular Science Laboratory, National Institute of Immunology, New Delhi, 110067, India
| | - Ashu Bhan Tiku
- Radiation and Cancer Therapeutics Lab, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
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12
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Gao Y, Hu YW, Duan RS, Yang SG, Zhou FQ, Wang RY. Time course analysis of sensory axon regeneration in vivo by directly tracing regenerating axons. Neural Regen Res 2020; 15:1160-1165. [PMID: 31823897 PMCID: PMC7034291 DOI: 10.4103/1673-5374.270315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 08/02/2019] [Accepted: 09/17/2019] [Indexed: 12/29/2022] Open
Abstract
Most current studies quantify axon regeneration by immunostaining regeneration-associated proteins, representing indirect measurement of axon lengths from both sensory neurons in the dorsal root ganglia and motor neurons in the spinal cord. Our recently developed method of in vivo electroporation of plasmid DNA encoding for enhanced green fluorescent protein into adult sensory neurons in the dorsal root ganglia provides a way to directly and specifically measure regenerating sensory axon lengths in whole-mount nerves. A mouse model of sciatic nerve compression was established by squeezing the sciatic nerve with tweezers. Plasmid DNA carrying enhanced green fluorescent protein was transfected by ipsilateral dorsal root ganglion electroporation 2 or 3 days before injury. Fluorescence distribution of dorsal root or sciatic nerve was observed by confocal microscopy. At 12 and 18 hours, and 1, 2, 3, 4, 5, and 6 days of injury, lengths of regenerated axons after sciatic nerve compression were measured using green fluorescence images. Apoptosis-related protein caspase-3 expression in dorsal root ganglia was determined by western blot assay. We found that in vivo electroporation did not affect caspase-3 expression in dorsal root ganglia. Dorsal root ganglia and sciatic nerves were successfully removed and subjected to a rapid tissue clearing technique. Neuronal soma in dorsal root ganglia expressing enhanced green fluorescent protein or fluorescent dye-labeled microRNAs were imaged after tissue clearing. The results facilitate direct time course analysis of peripheral nerve axon regeneration. This study was approved by the Institutional Animal Care and Use Committee of Guilin Medical University, China (approval No. GLMC201503010) on March 7, 2014.
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Affiliation(s)
- Yan Gao
- Guilin Medical University, Guilin, Guangxi Zhuang Autonomous Region, China
| | - Yi-Wen Hu
- Department of Orthopedic Surgery, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi Zhuang Autonomous Region, China
| | - Run-Shan Duan
- Department of Orthopedics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan Province, China
| | - Shu-Guang Yang
- Department of Orthopedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Feng-Quan Zhou
- Department of Orthopedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Rui-Ying Wang
- Department of Orthopedic Surgery, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi Zhuang Autonomous Region, China
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WANG Y, WANG Z. [Research progress on intrinsic signaling pathways in axon regeneration]. Zhejiang Da Xue Xue Bao Yi Xue Ban 2020; 49:82-89. [PMID: 32621408 PMCID: PMC8800775 DOI: 10.3785/j.issn.1008-9292.2020.02.08] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Accepted: 02/01/2020] [Indexed: 06/11/2023]
Abstract
The intrinsic regrowth ability of injured neurons is essential for axon regeneration and functional recovery. Recently, numerous intrinsic pathways that regulate axon regeneration have been discovered, among which the mitogen-activated protein kinase (MAPK) pathway and the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) pathway are arguably the best characterized examples. MAPK signaling pathway is involved in multiple processes including sensing injury signals, initiating and promoting axonal regrowth through regulating cytoskeleton dynamics and protein synthesis. The PI3K/Akt signaling pathway regulates axon regeneration mainly through gene transcription and translation. Combinatory manipulation of multiple regeneration-promoting signals can further improve the extend of axonal regrowth. This paper summarizes current progresses on axon regeneration studies in various organisms and discuss their potentials in promoting functional recovery in vivo.
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Affiliation(s)
| | - Zhiping WANG
- 王志萍(1980—),女,博士,研究员,博士生导师,主要从事神经发育和神经再生研究;E-mail:
;
https://orcid.org/0000-0001-8944-9557
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Circ-Spidr enhances axon regeneration after peripheral nerve injury. Cell Death Dis 2019; 10:787. [PMID: 31624232 PMCID: PMC6797756 DOI: 10.1038/s41419-019-2027-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 09/25/2019] [Accepted: 09/27/2019] [Indexed: 12/14/2022]
Abstract
Accumulating evidence suggests that circular RNAs (circRNAs) are abundant and play critical roles in the nervous system. However, their functions in axon regeneration after neuronal injury are unclear. Due to its robust regeneration capacity, peripheral nervous system is ideal for seeking the regulatory circRNAs in axon regeneration. In the present work, we obtained an expression profile of circRNAs in dorsal root ganglions (DRGs) after rat sciatic nerve crush injury by RNA sequencing (RNA-Seq) and found the expression level of circ-Spidr was obviously increased using quantitative real-time polymerase chain reaction (qRT-PCR). Furthermore, circ-Spidr was proved to be a circular RNA enriched in the cytoplasm of DRG neurons. Through in vitro and in vivo experiments, we determined that down-regulation of circ-Spidr could suppress axon regeneration of DRG neurons after sciatic nerve injury partially through modulating PI3K-Akt signaling pathway. Together, our results reveal a crucial role for circRNAs in regulating axon regeneration after neuronal injury which may further serve as a potential therapeutic avenue for neuronal injury repair.
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15
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Effects of siRNA-Mediated Knockdown of GSK3β on Retinal Ganglion Cell Survival and Neurite/Axon Growth. Cells 2019; 8:cells8090956. [PMID: 31443508 PMCID: PMC6769828 DOI: 10.3390/cells8090956] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 08/13/2019] [Accepted: 08/19/2019] [Indexed: 02/06/2023] Open
Abstract
There are contradictory reports on the role of the serine/threonine kinase isoform glycogen synthase kinase-3β (GSK3β) after injury to the central nervous system (CNS). Some report that GSK3 activity promotes axonal growth or myelin disinhibition, whilst others report that GSK3 activity prevents axon regeneration. In this study, we sought to clarify if suppression of GSK3β alone and in combination with the cellular-stress-induced factor RTP801 (also known as REDD1: regulated in development and DNA damage response protein), using translationally relevant siRNAs, promotes retinal ganglion cell (RGC) survival and neurite outgrowth/axon regeneration. Adult mixed retinal cell cultures, prepared from rats at five days after optic nerve crush (ONC) to activate retinal glia, were treated with siRNA to GSK3β (siGSK3β) alone or in combination with siRTP801 and RGC survival and neurite outgrowth were quantified in the presence and absence of Rapamycin or inhibitory Nogo-A peptides. In in vivo experiments, either siGSK3β alone or in combination with siRTP801 were intravitreally injected every eight days after ONC and RGC survival and axon regeneration was assessed at 24 days. Optimal doses of siGSK3β alone promoted significant RGC survival, increasing the number of RGC with neurites without affecting neurite length, an effect that was sensitive to Rapamycin. In addition, knockdown of GSK3β overcame Nogo-A-mediated neurite growth inhibition. Knockdown of GSK3β after ONC in vivo enhanced RGC survival but not axon number or length, without potentiating glial activation. Knockdown of RTP801 increased both RGC survival and axon regeneration, whilst the combined knockdown of GSK3β and RTP801 significantly increased RGC survival, neurite outgrowth, and axon regeneration over and above that observed for siGSK3β or siRTP801 alone. These results suggest that GSK3β suppression promotes RGC survival and axon initiation whilst, when in combination with RTP801, it also enhanced disinhibited axon elongation.
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Zhou Y, Zhang L, Fu X, Jiang Z, Tong R, Shi J, Li J, Zhong L. Design, Synthesis and in Vitro Tumor Cytotoxicity Evaluation of 3,5-Diamino-N-substituted Benzamide Derivatives as Novel GSK-3β Small Molecule Inhibitors. Chem Biodivers 2019; 16:e1900304. [PMID: 31338947 DOI: 10.1002/cbdv.201900304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Accepted: 07/23/2019] [Indexed: 02/05/2023]
Abstract
Glycogen synthase kinase-3 (GSK-3) plays an important regulatory role in various signaling pathways; such as PI3 K/AKT, which is closely related to the occurrence and development of tumors. At present, the most reported active GSK-3 inhibitors have the same structure: lactam ring or amide structure. To find out the GSK-3β small molecule inhibitor with novel, safe, efficient and more uncomplicated synthesis method, we analyzed in-depth reported crystal-binding patterns of GSK-3β small molecule inhibitor with GSK-3β protein, and designed and synthesized 17 non-reported 3,5-diamino-N-substituted benzamide compounds. Their structures were confirmed by 1 H-NMR, 13 C-NMR, and HR-MS. The preliminary screening of tumor cytotoxicity of compounds in vitro was detected by MTT, and their structure-activity relationships were illustrated. The results have shown that 3,5-diamino-N-[3-(trifluoromethyl)phenyl]benzamide (4d) exhibited significant tumor cytotoxicity against human colon cancer cells (HCT-116) with IC50 of 8.3 μm and showed commendable selectivity to GSK-3β. In addition, Compound 4d induced apoptosis to some extent and possessed modest PK properties.
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Affiliation(s)
- Yanping Zhou
- Personalized Drug Therapy Key Laboratory of Sichuan Province, Sichuan Academy of Medical Science & Sichuan Provincial People's Hospital, School of Medicine of University of Electronic Science and Technology of China, No. 32 West Second Section First Ring Road, Chengdu, 610072, P. R. China
| | - Lijuan Zhang
- Personalized Drug Therapy Key Laboratory of Sichuan Province, Sichuan Academy of Medical Science & Sichuan Provincial People's Hospital, School of Medicine of University of Electronic Science and Technology of China, No. 32 West Second Section First Ring Road, Chengdu, 610072, P. R. China
| | - Xiujuan Fu
- School of Pharmacy, Southwest Medicinal University, No. 319 Section 3, Zhongshan Road, Luzhou, 646000, P. R. China
| | - Zhongliang Jiang
- Department of Hematology, Miller School of Medicine, University of Miami, Miami, USA
| | - Rongsheng Tong
- Personalized Drug Therapy Key Laboratory of Sichuan Province, Sichuan Academy of Medical Science & Sichuan Provincial People's Hospital, School of Medicine of University of Electronic Science and Technology of China, No. 32 West Second Section First Ring Road, Chengdu, 610072, P. R. China
| | - Jianyou Shi
- Personalized Drug Therapy Key Laboratory of Sichuan Province, Sichuan Academy of Medical Science & Sichuan Provincial People's Hospital, School of Medicine of University of Electronic Science and Technology of China, No. 32 West Second Section First Ring Road, Chengdu, 610072, P. R. China
| | - Jian Li
- Department of Pharmacy, West China Hospital Sichuan University, Chengdu, 610041, P. R. China
| | - Lei Zhong
- Personalized Drug Therapy Key Laboratory of Sichuan Province, Sichuan Academy of Medical Science & Sichuan Provincial People's Hospital, School of Medicine of University of Electronic Science and Technology of China, No. 32 West Second Section First Ring Road, Chengdu, 610072, P. R. China
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17
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Berry M, Ahmed Z, Logan A. Return of function after CNS axon regeneration: Lessons from injury-responsive intrinsically photosensitive and alpha retinal ganglion cells. Prog Retin Eye Res 2019; 71:57-67. [DOI: 10.1016/j.preteyeres.2018.11.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 10/26/2018] [Accepted: 11/16/2018] [Indexed: 12/16/2022]
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18
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Zhou H, Wei M, Lu L, Chu T, Li X, Fu Z, Liu J, Kang Y, Liu L, Lou Y, Zhang C, Gao Y, Kong X, Feng S. Angiopoietin-2 induces the neuronal differentiation of mouse embryonic NSCs via phosphatidylinositol 3 kinase-Akt pathway-mediated phosphorylation of mTOR. Am J Transl Res 2019; 11:1895-1907. [PMID: 30972213 PMCID: PMC6456538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Accepted: 02/13/2019] [Indexed: 06/09/2023]
Abstract
The fate of neural stem cells (NSCs) is decided by numerous growth factors. Among these factors, the well-known angiogenic factor angiopoietin-2 (Ang-2) has been revealed to participate in neurogenesis separate from its role in angiogenesis. However, the effect of Ang-2 on the fate determination of mouse embryonic NSCs and the underlying mechanism remain unclear. This result of this study indicated that treatment of mouse embryonic NSCs with 200 ng/ml Ang-2 significantly promoted neuronal differentiation without affecting glial differentiation, and mammalian target of rapamycin (mTOR) was phosphorylated in a phosphatidylinositol 3-kinase (PI3K)/Akt-dependent manner during this process. Rapamycin, a specific mTOR inhibitor, suppressed the increase in neuronal differentiation stimulated by Ang-2, and this suppression did not result from an effect of Ang-2 or rapamycin on the apoptosis of differentiated NSCs. Collectively, our research demonstrates that PI3K/Akt pathway-mediated mTOR phosphorylation plays an important role in the Ang-2-enhanced neuronal differentiation of mouse embryonic NSCs.
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Affiliation(s)
- Hengxing Zhou
- Department of Orthopedics, Tianjin Medical University General HospitalNo. 154 Anshan Road, Heping District, Tianjin 300052, PR China
- Tianjin Neurological Institute, Key Laboratory of Post-Neuroinjury Neurorepair and Regeneration in The Central Nervous System, Ministry of EducationTianjin City, No. 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - Meng Wei
- Key Laboratory of Immuno Microenvironment and Disease of The Educational Ministry of China, Department of Immunology, Tianjin Medical UniversityNo. 22 Qixiangtai Road, Heping District, Tianjin 300070, PR China
| | - Lu Lu
- Department of Orthopedics, Tianjin Medical University General HospitalNo. 154 Anshan Road, Heping District, Tianjin 300052, PR China
- Tianjin Neurological Institute, Key Laboratory of Post-Neuroinjury Neurorepair and Regeneration in The Central Nervous System, Ministry of EducationTianjin City, No. 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - Tianci Chu
- Kosair Children’s Hospital Research Institute at The Department of Pediatrics, University of Louisville School of MedicineLouisville, Kentucky 40202, USA
| | - Xueying Li
- Key Laboratory of Immuno Microenvironment and Disease of The Educational Ministry of China, Department of Immunology, Tianjin Medical UniversityNo. 22 Qixiangtai Road, Heping District, Tianjin 300070, PR China
| | - Zheng Fu
- Key Laboratory of Immuno Microenvironment and Disease of The Educational Ministry of China, Department of Immunology, Tianjin Medical UniversityNo. 22 Qixiangtai Road, Heping District, Tianjin 300070, PR China
| | - Jun Liu
- Department of Orthopedics, Tianjin Medical University General HospitalNo. 154 Anshan Road, Heping District, Tianjin 300052, PR China
- Tianjin Neurological Institute, Key Laboratory of Post-Neuroinjury Neurorepair and Regeneration in The Central Nervous System, Ministry of EducationTianjin City, No. 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - Yi Kang
- Department of Orthopedics, Tianjin Medical University General HospitalNo. 154 Anshan Road, Heping District, Tianjin 300052, PR China
- Tianjin Neurological Institute, Key Laboratory of Post-Neuroinjury Neurorepair and Regeneration in The Central Nervous System, Ministry of EducationTianjin City, No. 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - Lu Liu
- Department of Orthopedics, Tianjin Medical University General HospitalNo. 154 Anshan Road, Heping District, Tianjin 300052, PR China
- Tianjin Neurological Institute, Key Laboratory of Post-Neuroinjury Neurorepair and Regeneration in The Central Nervous System, Ministry of EducationTianjin City, No. 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - Yongfu Lou
- Department of Orthopedics, Tianjin Medical University General HospitalNo. 154 Anshan Road, Heping District, Tianjin 300052, PR China
- Tianjin Neurological Institute, Key Laboratory of Post-Neuroinjury Neurorepair and Regeneration in The Central Nervous System, Ministry of EducationTianjin City, No. 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - Chi Zhang
- Department of Orthopedics, Tianjin Medical University General HospitalNo. 154 Anshan Road, Heping District, Tianjin 300052, PR China
- Tianjin Neurological Institute, Key Laboratory of Post-Neuroinjury Neurorepair and Regeneration in The Central Nervous System, Ministry of EducationTianjin City, No. 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - Yanzheng Gao
- Department of Orthopedics, Henan Province People’s HospitalZhengzhou 450000, Henan, China
| | - Xiaohong Kong
- School of Medicine, Nankai UniversityNo. 94 Weijin Road, Nankai District, Tianjin 300071, PR China
| | - Shiqing Feng
- Department of Orthopedics, Tianjin Medical University General HospitalNo. 154 Anshan Road, Heping District, Tianjin 300052, PR China
- Tianjin Neurological Institute, Key Laboratory of Post-Neuroinjury Neurorepair and Regeneration in The Central Nervous System, Ministry of EducationTianjin City, No. 154 Anshan Road, Heping District, Tianjin 300052, PR China
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AKT-dependent and -independent pathways mediate PTEN deletion-induced CNS axon regeneration. Cell Death Dis 2019; 10:203. [PMID: 30814515 PMCID: PMC6393504 DOI: 10.1038/s41419-018-1289-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/23/2018] [Accepted: 12/17/2018] [Indexed: 12/20/2022]
Abstract
Phosphatase and tensin homolog (PTEN) acts as a brake for the phosphatidylinositol 3-kinase–AKT–mTOR complex 1 (mTORC1) pathway, the deletion of which promotes potent central nervous system (CNS) axon regeneration. Previously, we demonstrated that AKT activation is sufficient to promote CNS axon regeneration to a lesser extent than PTEN deletion. It is still questionable whether AKT is entirely responsible for the regenerative effect of PTEN deletion on CNS axons. Here, we show that blocking AKT or its downstream effectors, mTORC1 and GSK3β, significantly reduces PTEN deletion-induced mouse optic nerve regeneration, indicating the necessary role of AKT-dependent signaling. However, AKT is only marginally activated in PTEN-null mice due to mTORC1-mediated feedback inhibition. That combining PTEN deletion with AKT overexpression or GSK3β deletion achieves significantly more potent axonal regeneration suggests an AKT-independent pathway for axon regeneration. Elucidating the AKT-independent pathway is required to develop effective strategies for CNS axon regeneration.
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The Anti-Tumor Agent Sodium Selenate Decreases Methylated PP2A, Increases GSK3βY216 Phosphorylation, Including Tau Disease Epitopes and Reduces Neuronal Excitability in SHSY-5Y Neurons. Int J Mol Sci 2019; 20:ijms20040844. [PMID: 30781361 PMCID: PMC6412488 DOI: 10.3390/ijms20040844] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 02/12/2019] [Accepted: 02/12/2019] [Indexed: 12/20/2022] Open
Abstract
Selenium application as sodium selenate was repeatedly shown to have anti-carcinogenic properties by increasing levels of the serine/ threonine protein phosphatase 2A (PP2A) in cancer cells. PP2A has a prominent role in cell development, homeostasis, and in neurons regulates excitability. PP2A, GSK3β and Tau reside together in a complex, which facilitates their interaction and (dys)-function as has been reported for several neurological disorders. In this study we recorded maximum increase in total PP2A at 3 µM sodium selenate in a neuron cell line. In conjunction with these data, whole-cell electrophysiological studies revealed that this concentration had maximum effect on membrane potentials, conductance and currents. Somewhat surprisingly, the catalytically active form, methylated PP2A (mePP2A) was significantly decreased. In close correlation to these data, the phosphorylation state of two substrate proteins, sensitive to PP2A activity, GSK3β and Tau were found to be increased. In summary, our data reveal that sodium selenate enhances PP2A levels, but reduces catalytic activity of PP2A in a dose dependent manner, which fails to reduce Tau and GSK3β phosphorylation under physiological conditions, indicating an alternative route in the rescue of cell pathology in neurological disorders.
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Jiang J, Hu Y, Zhang B, Shi Y, Zhang J, Wu X, Yao P. MicroRNA-9 regulates mammalian axon regeneration in peripheral nerve injury. Mol Pain 2018; 13:1744806917711612. [PMID: 28480796 PMCID: PMC5464514 DOI: 10.1177/1744806917711612] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Effective axon regeneration is achieved mainly by precise regulation of gene expression after peripheral nerve injury. MicroRNAs play an important role in controlling axon regeneration owe to its key epigenetic function in regulating gene expression. Here, we reveal that microRNA-9 (miR-9) may be a new suppressor of axon regeneration and FoxP1 is the functional target of miR-9. High level of endogenous miR-9 in sensory neurons inhibited axon regeneration in vitro and in vivo. In addition, the regulatory effect of miR-9 was mediated by changes in FoxP1 levels. Full rescuing effect of axon regeneration was achieved by FoxP1 up-regulation. Most importantly, we showed that miR-9-FoxP1 might be a new signaling pathway to regulate mammalian axon regrowth. Moreover, we provided the first evidence that maintaining a higher level of FoxP1 in sensory neurons by the microRNA is necessary for efficient axon regeneration.
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Affiliation(s)
- Jingjing Jiang
- 1Department of Anesthesiology, Shengjing Hospital of China Medical University, Shenyang,China
| | - Yiwen Hu
- Department of OrthopedicSurgery,The First Affiliated Hospital of China Medical University, Shenyang,China
| | - Boyin Zhang
- 3Department of Orthopedic Surgery, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Yao Shi
- 4Department of Pain Management, Shengjing Hospital of China Medical University, Shenyang, China
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Li Q, Qian C, Zhou FQ. Investigating Mammalian Axon Regeneration: In Vivo Electroporation of Adult Mouse Dorsal Root Ganglion. JOURNAL OF VISUALIZED EXPERIMENTS : JOVE 2018:58171. [PMID: 30222165 PMCID: PMC6235079 DOI: 10.3791/58171] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Electroporation is an essential non-viral gene transfection approach to introduce DNA plasmids or small RNA molecules into cells. A sensory neuron in the dorsal root ganglion (DRGs) extends a single axon with two branches. One branch goes to the peripheral nerve (peripheral branch), and the other branch enters the spinal cord through the dorsal root (central branch). After the neural injury, the peripheral branch regenerates robustly whereas the central branch does not regenerate. Due to the high regenerative capacity, sensory axon regeneration has been widely used as a model system to study mammalian axon regeneration in both the peripheral nervous system (PNS) and the central nervous system (CNS). Here, we describe a previously established approach protocol to manipulate gene expression in mature sensory neurons in vivo via electroporation. Based on transfection with plasmids or small RNA oligos (siRNAs or microRNAs), the approach allows for both loss- and gain-of-function experiments to study the roles of genes-of-interests or microRNAs in regulation of axon regeneration in vivo. In addition, the manipulation of gene expression in vivo can be controlled both spatially and temporally within a relatively short time course. This model system provides a unique tool to investigate the molecular mechanisms by which mammalian axon regeneration is regulated in vivo.
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Affiliation(s)
- Qiao Li
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine
| | - Cheng Qian
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine
| | - Feng-Quan Zhou
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine,The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine
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Abstract
Glycogen synthase kinase-3 beta (GSK3β) is principally is a glycogen synthase phosphorylating enzyme that is well known for its role in muscle metabolism. GSK3β is a serine/threonine protein Kinase, which is responsible for several essential roles in mammalian cells. This enzyme is implicated in the pathophysiology of many conditions involved in homeostasis and cellular immigration. GSK3β is involved in several pathways leading to neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. Increasing evidence has shown the potential importance of GSK3β in ischemic heart disease and ischemia-reperfusion pathologies. Reperfusion injury may occur in tissues after prolonged ischemia following reperfusion. Reperfusion injury can be life threatening. Reperfusion injury occurs due to a change in ionic homeostasis, excess free radical production, mitochondrial damage and cell death. There are however clear, cardiac-protective signals; although the molecular pathophysiology is not clearly understood. In normal physiology, GSK3β has a critical role in the cytoprotective pathway. However, it`s controversial role in ischemia and ischemia-reperfusion is a topic of current interest. In this review, we have opted to focus on GSK3β interactions with mitochondria in ischemic heart disease and expand on the therapeutic interventions.
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Jiang B, Zhang T, Liu F, Sun Z, Shi H, Hua D, Yang C. The co-stimulatory molecule B7-H3 promotes the epithelial-mesenchymal transition in colorectal cancer. Oncotarget 2017; 7:31755-71. [PMID: 27145365 PMCID: PMC5077974 DOI: 10.18632/oncotarget.9035] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 03/31/2016] [Indexed: 12/17/2022] Open
Abstract
B7-H3, first recognized as a co-stimulatory molecule, is abnormally expressed in cancer tissues and is associated with cancer metastasis and a poor prognosis. However, as an initial event of metastasis, the relationship between the Epithelial-Mesenchymal Transition (EMT ) in cancer cells and B7-H3 has still not been investigated. In this study, we first analyzed B7-H3 expression by immunohistochemistry in colorectal cancer tissues. B7-H3 was expressed in the cancer cell membrane and was associated with the T stage of colorectal cancer; it also showed a positive correlation with MMP2 and MMP9 expression in cancer tissues. Over-expression of B7-H3 in SW480 cells allowed cancer cells to invade and metastasize more than the control cells, whereas invasion and metastasis capabilities were decreased after B7-H3 was knocked down in Caco-2 cells. We further showed that B7-H3 down-regulated the expression of E-cadherin and β-catenin and up-regulated N-cadherin and Vimentin expression, implying that B7-H3 promoted the EMT in colorectal cancer cells. We also checked another character of the EMT, the stemness of cancer cells. CD133, CD44 and Oct4 were significantly elevated after the SW480 cells were transfected with B7-H3 and reduced in Caco-2 cells after B7-H3 was inhibited. In subsequent studies, we proved that B7-H3 upregulated the expression of Smad1 via PI3K-Akt. In conclusion, B7-H3 promotes the EMT in colorectal cancer cells by activating the PI3K-Akt pathway and upregulating the expression of Smad1.
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Affiliation(s)
- Bo Jiang
- Department of Medical Oncology, Beijing Institute of Translational Medicine, Chinese Academy of Sciences/Cancer Center, Aviation General Hospital, Beijing, China
| | - Ting Zhang
- Institute of Cancer, Affiliated Hospital of Jiangnan University, Wuxi, Jiangsu, China
| | - Fen Liu
- Institute of Cancer, Affiliated Hospital of Jiangnan University, Wuxi, Jiangsu, China
| | - Zhangzhang Sun
- Department of Medical Oncology, Affiliated Hospital of Jiangnan University, Wuxi, Jiangsu, China
| | - Hanping Shi
- Department of Medical Oncology, Beijing Institute of Translational Medicine, Chinese Academy of Sciences/Cancer Center, Aviation General Hospital, Beijing, China
| | - Dong Hua
- Department of Medical Oncology, Affiliated Hospital of Jiangnan University, Wuxi, Jiangsu, China
| | - Chen Yang
- Department of Nuclear-Medicine, Suzhou Hospital Affiliated to Nanjing Medical University, Suzhou, Jiangsu, China
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Haque N, Kasim NHA, Kassim NLA, Rahman MT. Autologous serum supplement favours in vitro regenerative paracrine factors synthesis. Cell Prolif 2017; 50. [PMID: 28682474 DOI: 10.1111/cpr.12354] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 04/28/2017] [Indexed: 12/27/2022] Open
Abstract
OBJECTIVES Foetal bovine serum (FBS) is often the serum supplement of choice for in vitro human cell culture. This study compares the effect of FBS and autologous human serum (AuHS) supplement in human peripheral blood mononuclear cell (PBMC) culture to prepare secretome. MATERIALS AND METHODS The PBMC (n = 7) were cultured either in RPMI-1640 containing L-glutamine and 50 units/ml Penicillin-Streptomycin (BM) or in BM with either AuHS or FBS. Viability, proliferation and differentiation of PBMC were evaluated. Paracrine factors present in the secretomes (n = 6) were analysed using ProcartaPlex Human Cytokine panel (17 plex). Ingenuity Pathway Analysis (IPA) was performed to predict activation or inhibition of biological functions related to tissue regeneration. RESULTS The viability of PBMC that were cultured with FBS supplement was significantly reduced at 96 h compared to those at 0 and 24 h (P < .05). While the reduction of the viability of PBMC that were cultured with AuHS supplement was not significantly different compared to those at 0 and 24 h. The FBS secretomes prepared at 24 h was found to contain significantly higher amount of EGF (P < .05) compared to that in AuHS or BM secretome. The AuHS secretomes contained significantly higher amount of HGF at 24 (P < .05) and 96 h (P < .01), and VEGF-A at 24 h (P < .05) compared to those in the FBS secretomes. SDF-1 was not detected in the FBS secretomes prepared at either 24 or 96 hours. Double immunocytochemical staining revealed a marked increase in co-localization of SDF-1 and its receptor in PBMC that were cultured with AuHS supplement compared to that cultured with FBS supplement. CONCLUSION In secretome preparation, AuHS supplement favours synthesis of paracrine factors that are needed for regenerative therapy.
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Affiliation(s)
- Nazmul Haque
- Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia.,Regenerative Dentistry Research Group, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
| | - Noor Hayaty Abu Kasim
- Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia.,Regenerative Dentistry Research Group, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
| | - Noor Lide Abu Kassim
- Faculty of Education, International Islamic University Malaysia, Kuala Lumpur, Malaysia
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26
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Swiatkowski P, Nikolaeva I, Kumar G, Zucco A, Akum BF, Patel MV, D'Arcangelo G, Firestein BL. Role of Akt-independent mTORC1 and GSK3β signaling in sublethal NMDA-induced injury and the recovery of neuronal electrophysiology and survival. Sci Rep 2017; 7:1539. [PMID: 28484273 PMCID: PMC5431483 DOI: 10.1038/s41598-017-01826-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 04/03/2017] [Indexed: 01/02/2023] Open
Abstract
Glutamate-induced excitotoxicity, mediated by overstimulation of N-methyl-D-aspartate (NMDA) receptors, is a mechanism that causes secondary damage to neurons. The early phase of injury causes loss of dendritic spines and changes to synaptic activity. The phosphatidylinositol-4,5-bisphosphate 3-kinase/Akt/ mammalian target of rapamycin (PI3K/Akt/mTOR) pathway has been implicated in the modulation and regulation of synaptic strength, activity, maturation, and axonal regeneration. The present study focuses on the physiology and survival of neurons following manipulation of Akt and several downstream targets, such as GSK3β, FOXO1, and mTORC1, prior to NMDA-induced injury. Our analysis reveals that exposure to sublethal levels of NMDA does not alter phosphorylation of Akt, S6, and GSK3β at two and twenty four hours following injury. Electrophysiological recordings show that NMDA-induced injury causes a significant decrease in spontaneous excitatory postsynaptic currents at both two and twenty four hours, and this phenotype can be prevented by inhibiting mTORC1 or GSK3β, but not Akt. Additionally, inhibition of mTORC1 or GSK3β promotes neuronal survival following NMDA-induced injury. Thus, NMDA-induced excitotoxicity involves a mechanism that requires the permissive activity of mTORC1 and GSK3β, demonstrating the importance of these kinases in the neuronal response to injury.
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Affiliation(s)
- Przemyslaw Swiatkowski
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA.,Graduate Program in Molecular Biosciences, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA
| | - Ina Nikolaeva
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA.,Graduate Program in Molecular Biosciences, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA
| | - Gaurav Kumar
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA
| | - Avery Zucco
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA.,Graduate Program in Neurosciences, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA
| | - Barbara F Akum
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA
| | - Mihir V Patel
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA.,Graduate Program in Neurosciences, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA
| | - Gabriella D'Arcangelo
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA
| | - Bonnie L Firestein
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA.
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27
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Ko HR, Kwon IS, Hwang I, Jin EJ, Shin JH, Brennan-Minnella AM, Swanson R, Cho SW, Lee KH, Ahn JY. Akt1-Inhibitor of DNA binding2 is essential for growth cone formation and axon growth and promotes central nervous system axon regeneration. eLife 2016; 5. [PMID: 27938661 PMCID: PMC5153247 DOI: 10.7554/elife.20799] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 11/28/2016] [Indexed: 02/02/2023] Open
Abstract
Mechanistic studies of axon growth during development are beneficial to the search for neuron-intrinsic regulators of axon regeneration. Here, we discovered that, in the developing neuron from rat, Akt signaling regulates axon growth and growth cone formation through phosphorylation of serine 14 (S14) on Inhibitor of DNA binding 2 (Id2). This enhances Id2 protein stability by means of escape from proteasomal degradation, and steers its localization to the growth cone, where Id2 interacts with radixin that is critical for growth cone formation. Knockdown of Id2, or abrogation of Id2 phosphorylation at S14, greatly impairs axon growth and the architecture of growth cone. Intriguingly, reinstatement of Akt/Id2 signaling after injury in mouse hippocampal slices redeemed growth promoting ability, leading to obvious axon regeneration. Our results suggest that Akt/Id2 signaling is a key module for growth cone formation and axon growth, and its augmentation plays a potential role in CNS axonal regeneration. DOI:http://dx.doi.org/10.7554/eLife.20799.001
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Affiliation(s)
- Hyo Rim Ko
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Il-Sun Kwon
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Inwoo Hwang
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Eun-Ju Jin
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Joo-Ho Shin
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Angela M Brennan-Minnella
- The Department of Neurology, University of California, San Francisco Medical Center, San Francisco, United States
| | - Raymond Swanson
- The Department of Neurology, University of California, San Francisco Medical Center, San Francisco, United States
| | - Sung-Woo Cho
- Department of Biochemistry and Molecular Biology, University of Ulsan, College of Medicine, Seoul, Republic of Korea
| | - Kyung-Hoon Lee
- Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Department of Anatomy, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Jee-Yin Ahn
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
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28
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Probing the PI3K/Akt/mTor pathway using 31P-NMR spectroscopy: routes to glycogen synthase kinase 3. Sci Rep 2016; 6:36544. [PMID: 27811956 PMCID: PMC5109916 DOI: 10.1038/srep36544] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 10/17/2016] [Indexed: 01/05/2023] Open
Abstract
Akt is an intracellular signalling pathway that serves as an essential link between cell surface receptors and cellular processes including proliferation, development and survival. The pathway has many downstream targets including glycogen synthase kinase3 which is a major regulatory kinase for cell cycle transit as well as controlling glycogen synthase activity. The Akt pathway is frequently up-regulated in cancer due to overexpression of receptors such as the epidermal growth factor receptor, or mutation of signalling pathway kinases resulting in inappropriate survival and proliferation. Consequently anticancer drugs have been developed that target this pathway. MDA-MB-468 breast and HCT8 colorectal cancer cells were treated with inhibitors including LY294002, MK2206, rapamycin, AZD8055 targeting key kinases in/associated with Akt pathway and the consistency of changes in 31P-NMR-detecatable metabolite content of tumour cells was examined. Treatment with the Akt inhibitor MK2206 reduced phosphocholine levels in MDA-MB-468 cells. Treatment with either the phosphoinositide-3-kinase inhibitor, LY294002 and pan-mTOR inhibitor, AZD8055 but not pan-Akt inhibitor MK2206 increased uridine-5′-diphosphate-hexose cell content which was suppressed by co-treatment with glycogen synthase kinase 3 inhibitor SB216763. This suggests that there is an Akt-independent link between phosphoinositol-3-kinase and glycogen synthase kinase3 and demonstrates the potential of 31P-NMR to probe intracellular signalling pathways.
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29
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The age factor in axonal repair after spinal cord injury: A focus on neuron-intrinsic mechanisms. Neurosci Lett 2016; 652:41-49. [PMID: 27818358 DOI: 10.1016/j.neulet.2016.11.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 10/26/2016] [Accepted: 11/01/2016] [Indexed: 11/27/2022]
Abstract
Age is an important consideration for recovery and repair after spinal cord injury. Spinal cord injury is increasingly affecting the middle-aged and aging populations. Despite rapid progress in research to promote axonal regeneration and repair, our understanding of how age can modulate this repair is rather limited. In this review, we discuss the literature supporting the notion of an age-dependent decline in axonal growth after central nervous system (CNS) injury. While both neuron-intrinsic and extrinsic factors are involved in the control of axon growth after injury, here we focus on possible intrinsic mechanisms for this age-dependent decline.
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30
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Hu YW, Jiang JJ, Yan-Gao, Wang RY, Tu GJ. MicroRNA-210 promotes sensory axon regeneration of adult mice in vivo and in vitro. Neurosci Lett 2016; 622:61-6. [PMID: 27102143 DOI: 10.1016/j.neulet.2016.04.034] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 04/12/2016] [Accepted: 04/14/2016] [Indexed: 12/20/2022]
Abstract
Axon regeneration as a critical step in nerve repairing and remodeling after peripheral nerve injury relies on regulation of gene expression. MicroRNAs are emerging to be important epigenetic regulators of gene expression to control axon regeneration. Here we used a novel in vivo electroporation approach to transfect microRNA-210 (miR-210) or siRNAs to adult mice dorsal root ganglion (DRG) neurons, measured the axon length 3days after sciatic nerve crush or dissociated DRG cultures in vitro to detect the effect of miR-210 in sensory axon regeneration. Importantly, we found that miR-210 overexpression could promote sensory axon regeneration and inhibit apoptsosis by ephrin-A3 (EFNA3). In addition, inhibition of endogenous miR-210 in DRG neurons impaired axon regeneration in vitro and in vivo, the regulatory effect of miR-210 was mediated by increased expression of EFNA3 because downregulation of EFNA3 fully rescued axon regeneration. We thus demonstrate that miR-210 is a new physiological regulator of sensory axon regeneration, and EFNA3 may be the functional target of miR-210. We conclude that miR-210 may play an important role in sensory axon regeneration.
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Affiliation(s)
- Yi-Wen Hu
- Department of Orthopaedic Surgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, 110000, China; Guilin Medical University, Guilin, Guangxi, 541001, China
| | - Jing-Jing Jiang
- Department of Anesthesiology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, 110004, China
| | - Yan-Gao
- Guilin Medical University, Guilin, Guangxi, 541001, China
| | - Rui-Ying Wang
- Guilin Medical University, Guilin, Guangxi, 541001, China
| | - Guan-Jun Tu
- Department of Orthopaedic Surgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, 110000, China.
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31
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Miao L, Yang L, Huang H, Liang F, Ling C, Hu Y. mTORC1 is necessary but mTORC2 and GSK3β are inhibitory for AKT3-induced axon regeneration in the central nervous system. eLife 2016; 5:e14908. [PMID: 27026523 PMCID: PMC4841781 DOI: 10.7554/elife.14908] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 03/21/2016] [Indexed: 01/11/2023] Open
Abstract
Injured mature CNS axons do not regenerate in mammals. Deletion of PTEN, the negative regulator of PI3K, induces CNS axon regeneration through the activation of PI3K-mTOR signaling. We have conducted an extensive molecular dissection of the cross-regulating mechanisms in axon regeneration that involve the downstream effectors of PI3K, AKT and the two mTOR complexes (mTORC1 and mTORC2). We found that the predominant AKT isoform in CNS, AKT3, induces much more robust axon regeneration than AKT1 and that activation of mTORC1 and inhibition of GSK3β are two critical parallel pathways for AKT-induced axon regeneration. Surprisingly, phosphorylation of T308 and S473 of AKT play opposite roles in GSK3β phosphorylation and inhibition, by which mTORC2 and pAKT-S473 negatively regulate axon regeneration. Thus, our study revealed a complex neuron-intrinsic balancing mechanism involving AKT as the nodal point of PI3K, mTORC1/2 and GSK3β that coordinates both positive and negative cues to regulate adult CNS axon regeneration. DOI:http://dx.doi.org/10.7554/eLife.14908.001 The central nervous system consists of the neurons that make up the brain and spinal cord. An important part of a neuron is the long, slender projection along which electrical signals travel, called the axon. In the central nervous system of mammals, damaged axons cannot regrow, which is why spinal injuries or optic nerve injuries can result in life-long neuronal deficits. Recent studies have found that activating a particular signaling pathway in central nervous system neurons causes their axons to regenerate. A key protein in this pathway is called AKT. Several signaling cascades are triggered by AKT to regulate cell survival and growth, but it was not known how the different branches of the AKT pathway are involved in axon regeneration. Miao, Yang et al. have now investigated AKT’s role in axon regeneration using a range of approaches to manipulate signaling in damaged mouse neurons. This revealed that a particular form of AKT (called AKT3) causes damaged axons to regenerate to a greater extent than other forms of this protein. This response depends on two parallel pathways: one in which AKT3 activates a protein complex called mTORC1, and one where AKT3 inhibits a protein called GSK3β. In addition, another protein complex called mTORC2, which is closely related to mTORC1, helps to inhibit the activity of AKT3 on GSK3β and hence inhibits axon regeneration. These findings reveal that a complex balancing mechanism, with AKT at its center, coordinates the many signals that regulate axon regeneration. Future studies into this system could ultimately help to develop new treatments for brain and spinal injuries. DOI:http://dx.doi.org/10.7554/eLife.14908.002
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Affiliation(s)
- Linqing Miao
- Shriners Hospitals Pediatric Research Center, Temple University Lewis Katz School of Medicine, Philadelphia, United States
| | - Liu Yang
- Shriners Hospitals Pediatric Research Center, Temple University Lewis Katz School of Medicine, Philadelphia, United States
| | - Haoliang Huang
- Shriners Hospitals Pediatric Research Center, Temple University Lewis Katz School of Medicine, Philadelphia, United States
| | - Feisi Liang
- Shriners Hospitals Pediatric Research Center, Temple University Lewis Katz School of Medicine, Philadelphia, United States
| | - Chen Ling
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida College of Medicine, Gainesville, United States
| | - Yang Hu
- Shriners Hospitals Pediatric Research Center, Temple University Lewis Katz School of Medicine, Philadelphia, United States.,Department of Anatomy and Cell Biology, Temple University Lewis Katz School of Medicine, Philadelphia, United States
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32
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Guo X, Snider WD, Chen B. GSK3β regulates AKT-induced central nervous system axon regeneration via an eIF2Bε-dependent, mTORC1-independent pathway. eLife 2016; 5:e11903. [PMID: 26974342 PMCID: PMC4805534 DOI: 10.7554/elife.11903] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Accepted: 02/26/2016] [Indexed: 01/03/2023] Open
Abstract
Axons fail to regenerate after central nervous system (CNS) injury. Modulation of the PTEN/mTORC1 pathway in retinal ganglion cells (RGCs) promotes axon regeneration after optic nerve injury. Here, we report that AKT activation, downstream of Pten deletion, promotes axon regeneration and RGC survival. We further demonstrate that GSK3β plays an indispensable role in mediating AKT-induced axon regeneration. Deletion or inactivation of GSK3β promotes axon regeneration independently of the mTORC1 pathway, whereas constitutive activation of GSK3β reduces AKT-induced axon regeneration. Importantly, we have identified eIF2Bε as a novel downstream effector of GSK3β in regulating axon regeneration. Inactivation of eIF2Bε reduces both GSK3β and AKT-mediated effects on axon regeneration. Constitutive activation of eIF2Bε is sufficient to promote axon regeneration. Our results reveal a key role of the AKT-GSK3β-eIF2Bε signaling module in regulating axon regeneration in the adult mammalian CNS. DOI:http://dx.doi.org/10.7554/eLife.11903.001 The central nervous system consists of the neurons that make up the brain, retina, and spinal cord. Neurons transmit electrical signals along a cable-like structure called an axon. However, an axon cannot regenerate itself, and so injuries that crush or sever the axons can lead to permanent damage. This happens for two reasons: neurons don’t have the same regenerative ability as other cells, and the environment in the central nervous system restricts cell growth. The optic nerve transmits visual information from the eye to the brain. Studies in mice with a damaged optic nerve show that it is possible to regenerate the axons of neurons that lack a protein known as PTEN. These studies revealed one molecular pathway by which eliminating PTEN helps to boost the regrowth of axons. Now, Guo et al. identify another independent pathway by which eliminating PTEN helps promote axon regeneration in damaged mouse optic nerves. This pathway starts with a growth-promoting enzyme called AKT, which is turned on in neurons that lack PTEN. Indeed, injecting mice with an active form of this enzyme caused the optic nerve fiber to regrow in mice whose optic nerve had been crushed. Further experiments revealed that AKT activates a pathway in which another enzyme called GSK3β acts on a protein called eIF2Bε. A future challenge is to simultaneously manipulate the different signaling pathways that have been linked to axon regrowth to investigate whether this combined approach could help repair damage to the central nervous system. DOI:http://dx.doi.org/10.7554/eLife.11903.002
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Affiliation(s)
- Xinzheng Guo
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, United States
| | - William D Snider
- UNC Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Bo Chen
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, United States.,Department of Neurobiology, Yale University School of Medicine, New Haven, United States
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33
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Affiliation(s)
- Heike Diekmann
- Division of Experimental Neurology, Department of Neurology, Heinrich-Heine-University of Düsseldorf, Düsseldorf, Germany
| | - Dietmar Fischer
- Division of Experimental Neurology, Department of Neurology, Heinrich-Heine-University of Düsseldorf, Düsseldorf, Germany
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34
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Noh J, Wende AR, Olsen CD, Kim B, Bevins J, Zhu Y, Zhang QJ, Riehle C, Abel ED. Phosphoinositide dependent protein kinase 1 is required for exercise-induced cardiac hypertrophy but not the associated mitochondrial adaptations. J Mol Cell Cardiol 2015; 89:297-305. [PMID: 26476238 DOI: 10.1016/j.yjmcc.2015.10.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 09/28/2015] [Accepted: 10/12/2015] [Indexed: 01/17/2023]
Abstract
Phosphoinositide-dependent protein kinase-1 (PDPK1) is an important mediator of phosphatidylinositol 3-kinase (PI3K) signaling. We previously reported that PI3K but not Akt signaling mediates the increase in mitochondrial oxidative capacity following physiological cardiac hypertrophy. To determine if PDPK1 regulates these metabolic adaptations we examined mice with cardiomyocyte-specific heterozygous knockout of PDPK1 (cPDPK1(+/-)) after 5 wk. exercise swim training. Akt phosphorylation at Thr308 increased by 43% in wildtype (WT) mice but not in cPDPK1(+/-) mice following exercise training. Ventricular contractile function was not different between WT and cPDPK1(+/-) mice at baseline. In addition, exercise did not influence ventricular function in WT or cPDPK1(+/-) mice. Heart weight normalized to tibia length ratios increased by 13.8% in WT mice (6.2±0.2 vs. 7.1±0.2, P=0.001), but not in cPDPK1(+/-) (6.2±0.3 vs. 6.5±0.2, P=0.20) mice after swim training. Diastolic LV dimension increased in WT mice (3.7±0.1 vs. 4.0±0.1 mm, P=0.01) but not in cPDPK1(+/-) (3.8±0.1 vs. 3.7±0.1 mm, P=0.56) following swim training. Maximal mitochondrial oxygen consumption (VADP, nmol/min/mg) using palmitoyl carnitine as a substrate was significantly increased in mice of all genotypes following swim training (WT: 13.6±0.6 vs.16.1±0.9, P=0.04; cPDPK1(+/-): 12.4±0.6 vs.15.9±1.2, P=0.04). These findings suggest that PDPK1 is required for exercise-induced cardiac hypertrophy but does not contribute to exercise-induced increases in mitochondrial function.
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Affiliation(s)
- Junghyun Noh
- Program in Molecular Medicine and Division of Endocrinology, Metabolism and Diabetes, University of Utah School of Medicine, Salt Lake City, UT 84112, USA; Division of Endocrinology and Metabolism, College of Medicine, Inje University, Goyang, South Korea
| | - Adam R Wende
- Program in Molecular Medicine and Division of Endocrinology, Metabolism and Diabetes, University of Utah School of Medicine, Salt Lake City, UT 84112, USA; Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Curtis D Olsen
- Program in Molecular Medicine and Division of Endocrinology, Metabolism and Diabetes, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Bumjun Kim
- Program in Molecular Medicine and Division of Endocrinology, Metabolism and Diabetes, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Jack Bevins
- Program in Molecular Medicine and Division of Endocrinology, Metabolism and Diabetes, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Yi Zhu
- Program in Molecular Medicine and Division of Endocrinology, Metabolism and Diabetes, University of Utah School of Medicine, Salt Lake City, UT 84112, USA; Touchstone Diabetes Center, University of Texas Southwestern, Dallas, TX 75390, USA
| | - Quan-Jiang Zhang
- Program in Molecular Medicine and Division of Endocrinology, Metabolism and Diabetes, University of Utah School of Medicine, Salt Lake City, UT 84112, USA; Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Christian Riehle
- Program in Molecular Medicine and Division of Endocrinology, Metabolism and Diabetes, University of Utah School of Medicine, Salt Lake City, UT 84112, USA; Hannover Medical School, Department of Cardiology and Angiology, Carl-Neuberg-Str., 130625 Hannover, Germany
| | - E Dale Abel
- Program in Molecular Medicine and Division of Endocrinology, Metabolism and Diabetes, University of Utah School of Medicine, Salt Lake City, UT 84112, USA; Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
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35
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Jiang JJ, Liu CM, Zhang BY, Wang XW, Zhang M, Saijilafu, Zhang SR, Hall P, Hu YW, Zhou FQ. MicroRNA-26a supports mammalian axon regeneration in vivo by suppressing GSK3β expression. Cell Death Dis 2015; 6:e1865. [PMID: 26313916 PMCID: PMC4558520 DOI: 10.1038/cddis.2015.239] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 06/08/2015] [Accepted: 06/19/2015] [Indexed: 01/03/2023]
Abstract
MicroRNAs are emerging to be important epigenetic factors that control axon regeneration. Here, we report that microRNA-26a (miR-26a) is a physiological regulator of mammalian axon regeneration in vivo. We demonstrated that endogenous miR-26a acted to target specifically glycogen synthase kinase 3β (GSK3β) in adult mouse sensory neurons in vitro and in vivo. Inhibition of endogenous miR-26a in sensory neurons impaired axon regeneration in vitro and in vivo. Moreover, the regulatory effect of miR-26a was mediated by increased expression of GSK3β because downregulation or pharmacological inhibition of GSK3β fully rescued axon regeneration. Our results also suggested that the miR-26a-GSK3β pathway regulated axon regeneration at the neuronal soma by controlling gene expression. We provided biochemical and functional evidences that the regeneration-associated transcription factor Smad1 acted downstream of miR-26a and GSK3β to control sensory axon regeneration. Our study reveals a novel miR-26a-GSK3β-Smad1 signaling pathway in the regulation of mammalian axon regeneration. Moreover, we provide the first evidence that, in addition to inhibition of GSK3β kinase activity, maintaining a lower protein level of GSK3β in neurons by the microRNA is necessary for efficient axon regeneration.
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Affiliation(s)
- J-J Jiang
- Department of Anesthesiology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, People's Republic of China.,Department of Orthopaedic Surgery and Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - C-M Liu
- Department of Orthopaedic Surgery and Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.,State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100190, People's Repubic of China
| | - B-Y Zhang
- Department of Orthopaedic Surgery and Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - X-W Wang
- Department of Orthopaedic Surgery and Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - M Zhang
- Department of Orthopaedic Surgery and Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Saijilafu
- Department of Orthopaedic Surgery and Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.,Department of Orthopaedics, the First Affiliated Hospital, Orthopaedic Institute, Soochow University, Suzhou 215123, Jiangsu, People's Republic of China
| | - S-R Zhang
- Department of Orthopaedic Surgery and Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - P Hall
- Department of Orthopaedic Surgery and Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Y-W Hu
- Department of Orthopaedic Surgery and Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - F-Q Zhou
- Department of Orthopaedic Surgery and Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.,The Solomon H Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore 21287, MD, USA
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36
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Koh SH, Lo EH. The Role of the PI3K Pathway in the Regeneration of the Damaged Brain by Neural Stem Cells after Cerebral Infarction. J Clin Neurol 2015; 11:297-304. [PMID: 26320845 PMCID: PMC4596106 DOI: 10.3988/jcn.2015.11.4.297] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 05/25/2015] [Accepted: 05/28/2015] [Indexed: 01/01/2023] Open
Abstract
Neurologic deficits resulting from stroke remain largely intractable, which has prompted thousands of studies aimed at developing methods for treating these neurologic sequelae. Endogenous neurogenesis is also known to occur after brain damage, including that due to cerebral infarction. Focusing on this process may provide a solution for treating neurologic deficits caused by cerebral infarction. The phosphatidylinositol-3-kinase (PI3K) pathway is known to play important roles in cell survival, and many studies have focused on use of the PI3K pathway to treat brain injury after stroke. Furthermore, since the PI3K pathway may also play key roles in the physiology of neural stem cells (NSCs), eliciting the appropriate activation of the PI3K pathway in NSCs may help to improve the sequelae of cerebral infarction. This review describes the PI3K pathway, its roles in the brain and NSCs after cerebral infarction, and the therapeutic possibility of activating the pathway to improve neurologic deficits after cerebral infarction.
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Affiliation(s)
- Seong Ho Koh
- Neuroprotection Research Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. .,Department of Neurology, Hanyang University College of Medicine, Seoul, Korea
| | - Eng H Lo
- Neuroprotection Research Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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37
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Cuesto G, Jordán-Álvarez S, Enriquez-Barreto L, Ferrús A, Morales M, Acebes Á. GSK3β inhibition promotes synaptogenesis in Drosophila and mammalian neurons. PLoS One 2015; 10:e0118475. [PMID: 25764078 PMCID: PMC4357437 DOI: 10.1371/journal.pone.0118475] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 01/17/2015] [Indexed: 01/22/2023] Open
Abstract
The PI3K-dependent activation of AKT results in the inhibition of GSK3β in most signaling pathways. These kinases regulate multiple neuronal processes including the control of synapse number as shown for Drosophila and rodents. Alzheimer disease's patients exhibit high levels of circulating GSK3β and, consequently, pharmacological strategies based on GSK3β antagonists have been designed. The approach, however, has yielded inconclusive results so far. Here, we carried out a comparative study in Drosophila and rats addressing the role of GSK3β in synaptogenesis. In flies, the genetic inhibition of the shaggy-encoded GSK3β increases the number of synapses, while its upregulation leads to synapse loss. Likewise, in three weeks cultured rat hippocampal neurons, the pharmacological inhibition of GSK3β increases synapse density and Synapsin expression. However, experiments on younger cultures (12 days) yielded an opposite effect, a reduction of synapse density. This unexpected finding seems to unveil an age- and dosage-dependent differential response of mammalian neurons to the stimulation/inhibition of GSK3β, a feature that must be considered in the context of human adult neurogenesis and pharmacological treatments for Alzheimer's disease based on GSK3β antagonists.
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Affiliation(s)
- Germán Cuesto
- Structural Synaptic Plasticity Laboratory, Department of Neurodegenerative Diseases, Centro de Investigación Biomédica de La Rioja, Logroño, La Rioja, Spain
| | - Sheila Jordán-Álvarez
- Department of Cellular, Molecular and Developmental Neurobiology, Cajal Institute, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Lilian Enriquez-Barreto
- Structural Synaptic Plasticity Laboratory, Department of Neurodegenerative Diseases, Centro de Investigación Biomédica de La Rioja, Logroño, La Rioja, Spain
| | - Alberto Ferrús
- Department of Cellular, Molecular and Developmental Neurobiology, Cajal Institute, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Miguel Morales
- Structural Synaptic Plasticity Laboratory, Department of Neurodegenerative Diseases, Centro de Investigación Biomédica de La Rioja, Logroño, La Rioja, Spain
- * E-mail: (AA); (MM)
| | - Ángel Acebes
- Department of Cellular, Molecular and Developmental Neurobiology, Cajal Institute, Consejo Superior de Investigaciones Científicas, Madrid, Spain
- * E-mail: (AA); (MM)
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38
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The mTORC1 effectors S6K1 and 4E-BP play different roles in CNS axon regeneration. Nat Commun 2014; 5:5416. [PMID: 25382660 PMCID: PMC4228696 DOI: 10.1038/ncomms6416] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 09/29/2014] [Indexed: 01/29/2023] Open
Abstract
Using mouse optic nerve (ON) crush as a CNS injury model, we and others have found that activation of the mammalian target of rapamycin complex 1 (mTORC1) in mature retinal ganglion cells by deletion of the negative regulators, phosphatase and tensin homolog (PTEN) and tuberous sclerosis 1, promotes ON regeneration. mTORC1 activation inhibits eukaryotic translation initiation factor 4E-binding protein (4E-BP) and activates ribosomal protein S6 kinase 1 (S6K1), both of which stimulate translation. We reasoned that mTORC1’s regeneration-promoting effects might be separable from its deleterious effects by differential manipulation of its downstream effectors. Here we show that S6K1 activation, but not 4E-BP inhibition, is sufficient to promote axon regeneration. However, inhibition of 4E-BP is required for PTEN deletion-induced axon regeneration. Both activation and inhibition of S6K1 decrease the effect of PTEN deletion on axon regeneration, implicating a dual role of S6K1 in regulating axon growth.
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