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Slater PG, Cammarata GM, Samuelson AG, Magee A, Hu Y, Lowery LA. XMAP215 promotes microtubule-F-actin interactions to regulate growth cone microtubules during axon guidance in Xenopus laevis. J Cell Sci 2019; 132:jcs.224311. [PMID: 30890650 DOI: 10.1242/jcs.224311] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 03/08/2019] [Indexed: 12/24/2022] Open
Abstract
It has long been established that neuronal growth cone navigation depends on changes in microtubule (MT) and F-actin architecture downstream of guidance cues. However, the mechanisms by which MTs and F-actin are dually coordinated remain a fundamentally unresolved question. Here, we report that the well-characterized MT polymerase, XMAP215 (also known as CKAP5), plays an important role in mediating MT-F-actin interaction within the growth cone. We demonstrate that XMAP215 regulates MT-F-actin alignment through its N-terminal TOG 1-5 domains. Additionally, we show that XMAP215 directly binds to F-actin in vitro and co-localizes with F-actin in the growth cone periphery. We also find that XMAP215 is required for regulation of growth cone morphology and response to the guidance cue, Ephrin A5. Our findings provide the first strong evidence that XMAP215 coordinates MT and F-actin interaction in vivo We suggest a model in which XMAP215 regulates MT extension along F-actin bundles into the growth cone periphery and that these interactions may be important to control cytoskeletal dynamics downstream of guidance cues. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Paula G Slater
- Department of Biology, Boston College, Chestnut Hill, MA 02467, USA
| | | | | | - Alexandra Magee
- Department of Biology, Boston College, Chestnut Hill, MA 02467, USA
| | - Yuhan Hu
- Department of Cell Biology, Yale University, New Haven, CT 06520, USA
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52
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Cell-matrix tension contributes to hypoxia in astrocyte-seeded viscoelastic hydrogels composed of collagen and hyaluronan. Exp Cell Res 2019; 376:49-57. [PMID: 30658092 DOI: 10.1016/j.yexcr.2019.01.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 01/08/2019] [Accepted: 01/14/2019] [Indexed: 11/22/2022]
Abstract
Astrocyte activation is crucial for wound contraction and glial scar formation following central nervous system injury, but the mechanism by which activation leads to astrocyte contractility and matrix reorganization in the central nervous system (CNS) is unknown. Current means to measure cell traction forces within three-dimensional scaffolds are limited to analyzing individual or small groups of cells, within extracellular matrices, whereas gap junctions and other cell-cell adhesions connect astrocytes to form a functional syncytium within the glial scar. Here, we measure the viscoelastic properties of cell-seeded hydrogels to yield insight into the collective contractility of astrocytes as they exert tension on the surrounding matrix and change its bulk mechanical properties. Our results indicate that incorporation of the CNS matrix component hyaluronan into a collagen hydrogel increases expression of the intermediate filament protein GFAP and results in a higher shear storage modulus of the cell/matrix composite, establishing the correlation between astrocyte activation and increased cell contractility. The effects of thrombin and blebbistatin, known mediators of actomyosin-mediated contraction, verify that cell-matrix tension dictates the hydrogel mechanical properties. Viability assays indicate that increased cell traction exacerbates cell death at the center of the scaffold, and message level analysis reveals that cells in the hyaluronan-containing matrix have a ~ 3-fold increase in HIF-1α gene expression. Overall, these findings suggest that astrocyte activation not only increases cell traction, but may also contribute to hypoxia near sites of central nervous system injury.
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53
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Xiao WP, Ding LLQ, Min YJ, Yang HY, Yao HH, Sun J, Zhou X, Zeng XB, Yu W. Electroacupuncture Promoting Axonal Regeneration in Spinal Cord Injury Rats via Suppression of Nogo/NgR and Rho/ROCK Signaling Pathway. Neuropsychiatr Dis Treat 2019; 15:3429-3442. [PMID: 31997879 PMCID: PMC6918258 DOI: 10.2147/ndt.s216874] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 10/08/2019] [Indexed: 12/17/2022] Open
Abstract
PURPOSE To observe the changes of Nogo/NgR and Rho/ROCK signaling pathway-related gene and protein expression in rats with spinal cord injury (SCI) treated with electroacupuncture (EA) and to further investigate the possible mechanism of EA for treating SCI. METHODS Allen's method was used to create the SCI rat model. Sixty-four model rats were further subdivided into four subgroups, namely, the SCI model group (SCI), EA treatment group (EA), blocking agent Y27632 treatment group (Y27632) and EA+blocking agent Y27632 treatment group (EA+Y), according to the treatment received. The rats were subjected to EA and/or blocking agent Y27632 treatment. After 14 days, injured spinal cord tissue was extracted for analysis. The mRNA and protein expression levels were determined by real-time fluorescence quantitative PCR and Western blotting, respectively. Cell apoptosis changes in the spinal cord were evaluated by in situ hybridization. Hindlimb motor function in the rats was evaluated by Basso-Beattie-Bresnahan assessment methods. RESULTS Except for RhoA protein expression, compared with the SCI model group, EA, blocking agent Y27632 and EA+blocking agent Y27632 treatment groups had significantly reduced mRNA and protein expression of Nogo-A, NgR, LINGO-1, RhoA and ROCK II in spinal cord tissues, increased mRNA and protein expression of MLCP, decreased p-MYPT1 protein expression and p-MYPT1/MYPT1 ratio, and caspase3 expression, and improved lower limb movement function after treatment for 14 days (P<0.01 or <0.05). The combination of EA and the blocking agent Y27632 was superior to EA or blocking agent Y27632 treatment alone (P < 0.01 or <0.05). CONCLUSION EA may have an obvious inhibitory effect on the Nogo/NgR and Rho/ROCK signaling pathway after SCI, thereby reducing the inhibition of axonal growth, which may be a key mechanism of EA treatment for SCI.
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Affiliation(s)
- Wei-Ping Xiao
- Spinal Department of Orthopedics and Department of Acupuncture, Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi, People's Republic of China
| | - Li-Li-Qiang Ding
- Department of Hypertension, Shanghai Institute of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - You-Jiang Min
- Spinal Department of Orthopedics and Department of Acupuncture, Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi, People's Republic of China.,Department of Traditional Chinese Medicine, Shanghai Eighth People's Hospital, Shanghai, People's Republic of China
| | - Hua-Yuan Yang
- Institute of Traditional Chinese Medicine Engineering, Shanghai University of Traditional Chinese Medicine, Shanghai, People's Republic of China
| | - Hai-Hua Yao
- Department of Traditional Chinese Medicine, Shanghai Eighth People's Hospital, Shanghai, People's Republic of China
| | - Jie Sun
- Spinal Department of Orthopedics and Department of Acupuncture, Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi, People's Republic of China
| | - Xuan Zhou
- Spinal Department of Orthopedics and Department of Acupuncture, Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi, People's Republic of China
| | - Xue-Bo Zeng
- Spinal Department of Orthopedics and Department of Acupuncture, Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi, People's Republic of China
| | - Wan Yu
- Spinal Department of Orthopedics and Department of Acupuncture, Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi, People's Republic of China
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Dzyubenko E, Manrique-Castano D, Kleinschnitz C, Faissner A, Hermann DM. Role of immune responses for extracellular matrix remodeling in the ischemic brain. Ther Adv Neurol Disord 2018; 11:1756286418818092. [PMID: 30619510 PMCID: PMC6299337 DOI: 10.1177/1756286418818092] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 11/05/2018] [Indexed: 12/21/2022] Open
Abstract
Neuroinflammation is one of the key components contributing to the devastating outcome of ischemic stroke. Starting with stroke onset, inflammatory processes contribute both to cell damage and tissue remodeling. The early release of alarmins triggers the upregulation of multiple proinflammatory cytokines, resulting in the compromised integrity of the blood–brain barrier. From this moment on, the infiltration of peripheral immune cells, reactive gliosis and extracellular matrix (ECM) alterations become intricately intertwined and act as one unit during the tissue remodeling. While the mechanisms of leukocyte and glia activation are amply reviewed, the field of ECM modification remains as yet under explored. In this review, we focus on the interplay between neuroinflammatory cascades and ECM in the ischemic brain. By summarizing the currently available evidence obtained by in vitro research, animal experimentation and human studies, we aim to propose a new direction for the future investigation of stroke recovery.
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Affiliation(s)
- Egor Dzyubenko
- Department of Neurology, University Hospital Essen, Essen, Germany
| | | | | | - Andreas Faissner
- Department of Cell Morphology and Molecular Neurobiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Dirk M Hermann
- Department of Neurology, University Hospital Essen, Hufelandstraße 55, D-45122 Essen, Germany
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55
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Li H, Zhou X, Ye H, Sun X, Zhang P. Design, Synthesis, and Biological Evaluations of Several Fasudil Analogues. J Heterocycl Chem 2018. [DOI: 10.1002/jhet.3403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Hang Li
- College of Food Science and BioengineeringTianjin Agricultural University Tianjin 300072 People's Republic of China
| | - Xueyong Zhou
- College of Food Science and BioengineeringTianjin Agricultural University Tianjin 300072 People's Republic of China
| | - Hang Ye
- R&D of Danfoss (Tianjin) Ltd. Tianjin 301700 People's Republic of China
| | - Xi Sun
- College of Food Science and BioengineeringTianjin Agricultural University Tianjin 300072 People's Republic of China
| | - Pingping Zhang
- College of Food Science and BioengineeringTianjin Agricultural University Tianjin 300072 People's Republic of China
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56
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Goncalves K, Przyborski S. The utility of stem cells for neural regeneration. Brain Neurosci Adv 2018; 2:2398212818818071. [PMID: 32166173 PMCID: PMC7058206 DOI: 10.1177/2398212818818071] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Indexed: 12/22/2022] Open
Abstract
The use of stem cells in biomedical research is an extremely active area of science. This is because they provide tools that can be used both in vivo and vitro to either replace cells lost in degenerative processes, or to model such diseases to elucidate their underlying mechanisms. This review aims to discuss the use of stem cells in terms of providing regeneration within the nervous system, which is particularly important as neurons of the central nervous system lack the ability to inherently regenerate and repair lost connections. As populations are ageing, incidence of neurodegenerative diseases are increasing, highlighting the need to better understand the regenerative capacity and many uses of stem cells in this field.
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Affiliation(s)
| | - Stefan Przyborski
- Department of Biosciences, Durham University, Durham, UK.,Reprocell Europe, Sedgefield, UK
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57
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Miller KE, Suter DM. An Integrated Cytoskeletal Model of Neurite Outgrowth. Front Cell Neurosci 2018; 12:447. [PMID: 30534055 PMCID: PMC6275320 DOI: 10.3389/fncel.2018.00447] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 11/07/2018] [Indexed: 12/27/2022] Open
Abstract
Neurite outgrowth underlies the wiring of the nervous system during development and regeneration. Despite a significant body of research, the underlying cytoskeletal mechanics of growth and guidance are not fully understood, and the relative contributions of individual cytoskeletal processes to neurite growth are controversial. Here, we review the structural organization and biophysical properties of neurons to make a semi-quantitative comparison of the relative contributions of different processes to neurite growth. From this, we develop the idea that neurons are active fluids, which generate strong contractile forces in the growth cone and weaker contractile forces along the axon. As a result of subcellular gradients in forces and material properties, actin flows rapidly rearward in the growth cone periphery, and microtubules flow forward in bulk along the axon. With this framework, an integrated model of neurite outgrowth is proposed that hopefully will guide new approaches to stimulate neuronal growth.
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Affiliation(s)
- Kyle E Miller
- Department of Integrative Biology, Michigan State University, East Lansing, MI, United States
| | - Daniel M Suter
- Department of Biological Sciences, Purdue University, West Lafayette, IN, United States.,Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, United States.,Bindley Bioscience Center, Purdue University, West Lafayette, IN, United States.,Birck Nanotechnology Center, Purdue University, West Lafayette, IN, United States
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58
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Dyck S, Kataria H, Akbari-Kelachayeh K, Silver J, Karimi-Abdolrezaee S. LAR and PTPσ receptors are negative regulators of oligodendrogenesis and oligodendrocyte integrity in spinal cord injury. Glia 2018; 67:125-145. [PMID: 30394599 DOI: 10.1002/glia.23533] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 09/18/2018] [Accepted: 09/19/2018] [Indexed: 12/26/2022]
Abstract
Following spinal cord injury (SCI), the population of mature oligodendrocytes undergoes substantial cell death; promoting their preservation and replacement is a viable strategy for preserving axonal integrity and white matter repair in the injured spinal cord. Dramatic upregulation of matrix chondroitin sulfate proteoglycans (CSPGs) is shown to pose an obstacle to endogenous repair processes, and targeting CSPGs improves functional recovery after SCI. However, the cellular and molecular mechanisms underlying the inhibitory effects of CSPGs remain largely undefined. Modulation of CSPGs specific signaling receptors, leukocyte common antigen-related (LAR), and protein tyrosine phosphatase-sigma (PTPσ) allows us to uncover the role and mechanisms of CSPGs in regulating oligodendrocytes in SCI. Here, utilizing specific functionally blocking peptides in a clinically relevant model of contusive/compressive SCI in the rat, we demonstrate that inhibition of PTPσ and LAR receptors promotes oligodendrogenesis by endogenous precursor cells, attenuates caspase 3-mediated cell death in mature oligodendrocytes, and preserves myelin. In parallel in vitro systems, we have unraveled that CSPGs directly induce apoptosis in populations of neural precursor cells and oligodendrocyte progenitor cells and limit their ability for oligodendrocyte differentiation, maturation, and myelination. These negative effects of CSPGs are mediated through the activation of both LAR and PTPσ receptors and the downstream Rho/ROCK pathway. Thus, we have identified a novel inhibitory role for PTPσ and LAR in regulating oligodendrocyte differentiation and apoptosis in the injured adult spinal cord and a new feasible therapeutic strategy for optimizing endogenous cell replacement following SCI.
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Affiliation(s)
- Scott Dyck
- Department of Physiology and Pathophysiology, The Regenerative Medicine Program, The Spinal Cord Research Center, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Hardeep Kataria
- Department of Physiology and Pathophysiology, The Regenerative Medicine Program, The Spinal Cord Research Center, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Khashayar Akbari-Kelachayeh
- Department of Physiology and Pathophysiology, The Regenerative Medicine Program, The Spinal Cord Research Center, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Jerry Silver
- Department of Neuroscience, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Soheila Karimi-Abdolrezaee
- Department of Physiology and Pathophysiology, The Regenerative Medicine Program, The Spinal Cord Research Center, University of Manitoba, Winnipeg, Manitoba, Canada.,Children's Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada
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59
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Tran AP, Warren PM, Silver J. The Biology of Regeneration Failure and Success After Spinal Cord Injury. Physiol Rev 2018. [PMID: 29513146 DOI: 10.1152/physrev.00017.2017] [Citation(s) in RCA: 490] [Impact Index Per Article: 81.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Since no approved therapies to restore mobility and sensation following spinal cord injury (SCI) currently exist, a better understanding of the cellular and molecular mechanisms following SCI that compromise regeneration or neuroplasticity is needed to develop new strategies to promote axonal regrowth and restore function. Physical trauma to the spinal cord results in vascular disruption that, in turn, causes blood-spinal cord barrier rupture leading to hemorrhage and ischemia, followed by rampant local cell death. As subsequent edema and inflammation occur, neuronal and glial necrosis and apoptosis spread well beyond the initial site of impact, ultimately resolving into a cavity surrounded by glial/fibrotic scarring. The glial scar, which stabilizes the spread of secondary injury, also acts as a chronic, physical, and chemo-entrapping barrier that prevents axonal regeneration. Understanding the formative events in glial scarring helps guide strategies towards the development of potential therapies to enhance axon regeneration and functional recovery at both acute and chronic stages following SCI. This review will also discuss the perineuronal net and how chondroitin sulfate proteoglycans (CSPGs) deposited in both the glial scar and net impede axonal outgrowth at the level of the growth cone. We will end the review with a summary of current CSPG-targeting strategies that help to foster axonal regeneration, neuroplasticity/sprouting, and functional recovery following SCI.
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Affiliation(s)
- Amanda Phuong Tran
- Department of Neurosciences, Case Western Reserve University , Cleveland, Ohio ; and School of Biomedical Sciences, University of Leeds , Leeds , United Kingdom
| | - Philippa Mary Warren
- Department of Neurosciences, Case Western Reserve University , Cleveland, Ohio ; and School of Biomedical Sciences, University of Leeds , Leeds , United Kingdom
| | - Jerry Silver
- Department of Neurosciences, Case Western Reserve University , Cleveland, Ohio ; and School of Biomedical Sciences, University of Leeds , Leeds , United Kingdom
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60
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Curcio M, Bradke F. Axon Regeneration in the Central Nervous System: Facing the Challenges from the Inside. Annu Rev Cell Dev Biol 2018; 34:495-521. [DOI: 10.1146/annurev-cellbio-100617-062508] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
After an injury in the adult mammalian central nervous system (CNS), lesioned axons fail to regenerate. This failure to regenerate contrasts with axons’ remarkable potential to grow during embryonic development and after an injury in the peripheral nervous system (PNS). Several intracellular mechanisms—including cytoskeletal dynamics, axonal transport and trafficking, signaling and transcription of regenerative programs, and epigenetic modifications—control axon regeneration. In this review, we describe how manipulation of intrinsic mechanisms elicits a regenerative response in different organisms and how strategies are implemented to form the basis of a future regenerative treatment after CNS injury.
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Affiliation(s)
- Michele Curcio
- Laboratory for Axon Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany;,
| | - Frank Bradke
- Laboratory for Axon Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany;,
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61
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ROCK inhibition in models of neurodegeneration and its potential for clinical translation. Pharmacol Ther 2018; 189:1-21. [DOI: 10.1016/j.pharmthera.2018.03.008] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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62
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Zou JL, Sun JH, Qiu S, Chen SH, He FL, Li JC, Mao HQ, Liu XL, Quan DP, Zeng YS, Zhu QT. Spatial distribution affects the role of CSPGs in nerve regeneration via the actin filament-mediated pathway. Exp Neurol 2018; 307:37-44. [PMID: 29852179 DOI: 10.1016/j.expneurol.2018.05.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 05/24/2018] [Accepted: 05/27/2018] [Indexed: 11/28/2022]
Abstract
CSPGs are components of the extracellular matrix in the nervous system, where they serve as cues for axon guidance during development. After a peripheral nerve injury, CSPGs switch roles and become axon inhibitors and become diffusely distributed at the injury site. To investigate whether the spatial distribution of CSPGs affects their role, we combined in vitro DRG cultures with CSPG stripe or coverage assays to simulate the effect of a patterned substrate or dispersive distribution of CSPGs on growing neurites. We observed neurite steering at linear CSPG interfaces and neurite inhibition when diffused CSPGs covered the distal but not the proximal segment of the neurite. The repellent and inhibitory effects of CSPGs on neurite outgrowth were associated with the disappearance of focal actin filaments on growth cones. The application of an actin polymerization inducer, jasplakinolide, allowed neurites to break through the CSPG boundary and grow on CSPG-coated surfaces. The results of our study collectively reveal a novel mechanism that explains how the spatial distribution of CSPGs determines whether they act as a cue for axon guidance or as an axon-inhibiting factor. Increasing our understanding of this issue may promote the development of novel therapeutic strategies that regulate the spatial distributions of CSPGs to use them as an axon guidance cue.
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Affiliation(s)
- Jian-Long Zou
- Department of Microsurgery, Orthopedic Trauma and Hand Surgery, The First Affiliated Hospital, Sun Yat-sen University, No. 58, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Jia-Hui Sun
- Key Laboratory for Stem Cells and Tissue Engineering, Sun Yat-sen University, Ministry of Education, Guangzhou, Guangdong 510080, China
| | - Shuai Qiu
- Department of Microsurgery, Orthopedic Trauma and Hand Surgery, The First Affiliated Hospital, Sun Yat-sen University, No. 58, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Shi-Hao Chen
- PCFM Lab, GD HPPC Lab, School of Chemistry, Sun Yat-sen University, Guangzhou, Guangdong 510127, China
| | - Fu-Lin He
- Department of Microsurgery, Orthopedic Trauma and Hand Surgery, The First Affiliated Hospital, Sun Yat-sen University, No. 58, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Jia-Chun Li
- Orthopedics Department, The Third Affiliated Hospital, Sun Yat-sen University, 600 Tianhe Road, Guangzhou, Guangdong 510630, China
| | - Hai-Quan Mao
- Institute for NanoBioTechnology, Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Xiao-Lin Liu
- Department of Microsurgery, Orthopedic Trauma and Hand Surgery, The First Affiliated Hospital, Sun Yat-sen University, No. 58, Zhongshan 2nd Road, Guangzhou 510080, China; Guangdong Provincial Peripheral Nerve Tissue-engineering and Technology Research Center, Guangzhou 510080, China
| | - Da-Ping Quan
- PCFM Lab, GD HPPC Lab, School of Chemistry, Sun Yat-sen University, Guangzhou, Guangdong 510127, China
| | - Yuan-Shan Zeng
- Key Laboratory for Stem Cells and Tissue Engineering, Sun Yat-sen University, Ministry of Education, Guangzhou, Guangdong 510080, China
| | - Qing-Tang Zhu
- Department of Microsurgery, Orthopedic Trauma and Hand Surgery, The First Affiliated Hospital, Sun Yat-sen University, No. 58, Zhongshan 2nd Road, Guangzhou 510080, China; Guangdong Provincial Peripheral Nerve Tissue-engineering and Technology Research Center, Guangzhou 510080, China.
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63
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Zhang G, Hu J, Rodemer W, Li S, Selzer ME. RhoA activation in axotomy-induced neuronal death. Exp Neurol 2018; 306:76-91. [PMID: 29715475 DOI: 10.1016/j.expneurol.2018.04.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 04/18/2018] [Accepted: 04/27/2018] [Indexed: 01/11/2023]
Abstract
After spinal cord injury (SCI) in mammals, severed axons fail to regenerate, due to both extrinsic inhibitory factors, e.g., the chondroitin sulfate proteoglycans (CSPGs) and myelin-associated growth inhibitors (MAIs), and a developmental loss of intrinsic growth capacity. The latter is suggested by findings in lamprey that the 18 pairs of individually identified reticulospinal neurons vary greatly in their ability to regenerate their axons through the same spinal cord environment. Moreover, those neurons that are poor regenerators undergo very delayed apoptosis, and express common molecular markers after SCI. Thus the signaling pathways for retrograde cell death might converge with those inhibiting axon regeneration. Many extrinsic growth-inhibitory molecules activate RhoA, whereas inhibiting RhoA enhances axon growth. Whether RhoA also is involved in retrograde neuronal death after axotomy is less clear. Therefore, we cloned lamprey RhoA and correlated its mRNA expression and activation state with apoptosis signaling in identified reticulospinal neurons. RhoA mRNA was expressed widely in normal lamprey brain, and only slightly more in poorly-regenerating neurons than in good regenerators. However, within a day after spinal cord transection, RhoA mRNA was found in severed axon tips. Beginning at 5 days post-SCI RhoA mRNA was upregulated selectively in pre-apoptotic neuronal perikarya, as indicated by labelling with fluorescently labeled inhibitors of caspase activation (FLICA). After 2 weeks post-transection, RhoA expression decreased in the perikarya, and was translocated anterogradely into the axons. More striking than changes in RhoA mRNA levels, RhoA was continuously active selectively in FLICA-positive neurons through 9 weeks post-SCI. At that time, almost no neurons whose axons had regenerated were FLICA-positive. These findings are consistent with a role for RhoA activation in triggering retrograde neuronal death after SCI, and suggest that RhoA may be a point of convergence for inhibition of both axon regeneration and neuronal survival after axotomy.
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Affiliation(s)
- Guixin Zhang
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), USA
| | - Jianli Hu
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), USA
| | - William Rodemer
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), USA
| | - Shuxin Li
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), USA; Dept. Anatomy and Cell Biology, The Lewis Katz School of Medicine at Temple University, 3500 North Broad Street, Philadelphia, PA 19140, USA
| | - Michael E Selzer
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), USA; Dept. of Neurology, USA.
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The Extracellular Environment of the CNS: Influence on Plasticity, Sprouting, and Axonal Regeneration after Spinal Cord Injury. Neural Plast 2018; 2018:2952386. [PMID: 29849554 PMCID: PMC5932463 DOI: 10.1155/2018/2952386] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 01/22/2018] [Accepted: 02/06/2018] [Indexed: 11/17/2022] Open
Abstract
The extracellular environment of the central nervous system (CNS) becomes highly structured and organized as the nervous system matures. The extracellular space of the CNS along with its subdomains plays a crucial role in the function and stability of the CNS. In this review, we have focused on two components of the neuronal extracellular environment, which are important in regulating CNS plasticity including the extracellular matrix (ECM) and myelin. The ECM consists of chondroitin sulfate proteoglycans (CSPGs) and tenascins, which are organized into unique structures called perineuronal nets (PNNs). PNNs associate with the neuronal cell body and proximal dendrites of predominantly parvalbumin-positive interneurons, forming a robust lattice-like structure. These developmentally regulated structures are maintained in the adult CNS and enhance synaptic stability. After injury, however, CSPGs and tenascins contribute to the structure of the inhibitory glial scar, which actively prevents axonal regeneration. Myelin sheaths and mature adult oligodendrocytes, despite their important role in signal conduction in mature CNS axons, contribute to the inhibitory environment existing after injury. As such, unlike the peripheral nervous system, the CNS is unable to revert to a “developmental state” to aid neuronal repair. Modulation of these external factors, however, has been shown to promote growth, regeneration, and functional plasticity after injury. This review will highlight some of the factors that contribute to or prevent plasticity, sprouting, and axonal regeneration after spinal cord injury.
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65
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Tassew NG, Charish J, Shabanzadeh AP, Luga V, Harada H, Farhani N, D'Onofrio P, Choi B, Ellabban A, Nickerson PEB, Wallace VA, Koeberle PD, Wrana JL, Monnier PP. Exosomes Mediate Mobilization of Autocrine Wnt10b to Promote Axonal Regeneration in the Injured CNS. Cell Rep 2018; 20:99-111. [PMID: 28683327 DOI: 10.1016/j.celrep.2017.06.009] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 04/19/2017] [Accepted: 05/28/2017] [Indexed: 12/29/2022] Open
Abstract
Developing strategies that promote axonal regeneration within the injured CNS is a major therapeutic challenge, as axonal outgrowth is potently inhibited by myelin and the glial scar. Although regeneration can be achieved using the genetic deletion of PTEN, a negative regulator of the mTOR pathway, this requires inactivation prior to nerve injury, thus precluding therapeutic application. Here, we show that, remarkably, fibroblast-derived exosomes (FD exosomes) enable neurite growth on CNS inhibitory proteins. Moreover, we demonstrate that, upon treatment with FD exosomes, Wnt10b is recruited toward lipid rafts and activates mTOR via GSK3β and TSC2. Application of FD exosomes shortly after optic nerve injury promoted robust axonal regeneration, which was strongly reduced in Wnt10b-deleted animals. This work uncovers an intercellular signaling pathway whereby FD exosomes mobilize an autocrine Wnt10b-mTOR pathway, thereby awakening the intrinsic capacity of neurons for regeneration, an important step toward healing the injured CNS.
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Affiliation(s)
- Nardos G Tassew
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Krembil Discovery Tower, KDT-8-418, 60 Leonard Street, Toronto, ON M5T 2S8, Canada
| | - Jason Charish
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Krembil Discovery Tower, KDT-8-418, 60 Leonard Street, Toronto, ON M5T 2S8, Canada; Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Alireza P Shabanzadeh
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Krembil Discovery Tower, KDT-8-418, 60 Leonard Street, Toronto, ON M5T 2S8, Canada
| | - Valbona Luga
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 982 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Hidekiyo Harada
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Krembil Discovery Tower, KDT-8-418, 60 Leonard Street, Toronto, ON M5T 2S8, Canada
| | - Nahal Farhani
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Krembil Discovery Tower, KDT-8-418, 60 Leonard Street, Toronto, ON M5T 2S8, Canada
| | - Philippe D'Onofrio
- Department of Anatomy, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Brian Choi
- Department of Anatomy, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Ahmad Ellabban
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Krembil Discovery Tower, KDT-8-418, 60 Leonard Street, Toronto, ON M5T 2S8, Canada
| | - Philip E B Nickerson
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Krembil Discovery Tower, KDT-8-418, 60 Leonard Street, Toronto, ON M5T 2S8, Canada
| | - Valerie A Wallace
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Krembil Discovery Tower, KDT-8-418, 60 Leonard Street, Toronto, ON M5T 2S8, Canada; Department of Ophthalmology and Vision Science, Faculty of Medicine, University of Toronto, 340 College Street, Toronto, ON M5T 3A9, Canada
| | - Paulo D Koeberle
- Department of Anatomy, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Jeffrey L Wrana
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 982 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Philippe P Monnier
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Krembil Discovery Tower, KDT-8-418, 60 Leonard Street, Toronto, ON M5T 2S8, Canada; Department of Ophthalmology and Vision Science, Faculty of Medicine, University of Toronto, 340 College Street, Toronto, ON M5T 3A9, Canada; Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada.
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Dyck S, Kataria H, Alizadeh A, Santhosh KT, Lang B, Silver J, Karimi-Abdolrezaee S. Perturbing chondroitin sulfate proteoglycan signaling through LAR and PTPσ receptors promotes a beneficial inflammatory response following spinal cord injury. J Neuroinflammation 2018; 15:90. [PMID: 29558941 PMCID: PMC5861616 DOI: 10.1186/s12974-018-1128-2] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 03/12/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Traumatic spinal cord injury (SCI) results in upregulation of chondroitin sulfate proteoglycans (CSPGs) by reactive glia that impedes repair and regeneration in the spinal cord. Degradation of CSPGs is known to be beneficial in promoting endogenous repair mechanisms including axonal sprouting/regeneration, oligodendrocyte replacement, and remyelination, and is associated with improvements in functional outcomes after SCI. Recent evidence suggests that CSPGs may regulate secondary injury mechanisms by modulating neuroinflammation after SCI. To date, the role of CSPGs in SCI neuroinflammation remains largely unexplored. The recent discovery of CSPG-specific receptors, leukocyte common antigen-related (LAR) and protein tyrosine phosphatase-sigma (PTPσ), allows unraveling the cellular and molecular mechanisms of CSPGs in SCI. In the present study, we have employed parallel in vivo and in vitro approaches to dissect the role of CSPGs and their receptors LAR and PTPσ in modulating the inflammatory processes in the acute and subacute phases of SCI. METHODS In a clinically relevant model of compressive SCI in female Sprague Dawley rats, we targeted LAR and PTPσ by two intracellular functionally blocking peptides, termed ILP and ISP, respectively. We delivered ILP and ISP treatment intrathecally to the injured spinal cord in a sustainable manner by osmotic mini-pumps for various time-points post-SCI. We employed flow cytometry, Western blotting, and immunohistochemistry in rat SCI, as well as complementary in vitro studies in primary microglia cultures to address our questions. RESULTS We provide novel evidence that signifies a key immunomodulatory role for LAR and PTPσ receptors in SCI. We show that blocking LAR and PTPσ reduces the population of classically activated M1 microglia/macrophages, while promoting alternatively activated M2 microglia/macrophages and T regulatory cells. This shift was associated with a remarkable elevation in pro-regenerative immune mediators, interleukin-10 (IL-10), and Arginase-1. Our parallel in vitro studies in microglia identified that while CSPGs do not induce an M1 phenotype per se, they promote a pro-inflammatory phenotype. Interestingly, inhibiting LAR and PTPσ in M1 and M2 microglia positively modulates their inflammatory response in the presence of CSPGs, and harnesses their ability for phagocytosis and mobilization. Interestingly, our findings indicate that CSPGs regulate microglia, at least in part, through the activation of the Rho/ROCK pathway downstream of LAR and PTPσ. CONCLUSIONS We have unveiled a novel role for LAR and PTPσ in regulating neuroinflammation in traumatic SCI. Our findings provide new insights into the mechanisms by which manipulation of CSPG signaling can promote recovery from SCI. More importantly, this work introduces the potential of ILP/ISP as a viable strategy for modulating the immune response following SCI and other neuroinflammatory conditions of the central nervous system.
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Affiliation(s)
- Scott Dyck
- Department of Physiology and Pathophysiology, the Regenerative Medicine Program, the Spinal Cord Research Center, University of Manitoba, 629-Basic Medical Sciences Building, 745 Bannatyne Avenue, Winnipeg, MB, R3E 0J9, Canada
| | - Hardeep Kataria
- Department of Physiology and Pathophysiology, the Regenerative Medicine Program, the Spinal Cord Research Center, University of Manitoba, 629-Basic Medical Sciences Building, 745 Bannatyne Avenue, Winnipeg, MB, R3E 0J9, Canada
| | - Arsalan Alizadeh
- Department of Physiology and Pathophysiology, the Regenerative Medicine Program, the Spinal Cord Research Center, University of Manitoba, 629-Basic Medical Sciences Building, 745 Bannatyne Avenue, Winnipeg, MB, R3E 0J9, Canada
| | - Kallivalappil T Santhosh
- Department of Physiology and Pathophysiology, the Regenerative Medicine Program, the Spinal Cord Research Center, University of Manitoba, 629-Basic Medical Sciences Building, 745 Bannatyne Avenue, Winnipeg, MB, R3E 0J9, Canada
| | - Bradley Lang
- Department of Neuroscience, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Jerry Silver
- Department of Neuroscience, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Soheila Karimi-Abdolrezaee
- Department of Physiology and Pathophysiology, the Regenerative Medicine Program, the Spinal Cord Research Center, University of Manitoba, 629-Basic Medical Sciences Building, 745 Bannatyne Avenue, Winnipeg, MB, R3E 0J9, Canada.
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67
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Blanquie O, Bradke F. Cytoskeleton dynamics in axon regeneration. Curr Opin Neurobiol 2018; 51:60-69. [PMID: 29544200 DOI: 10.1016/j.conb.2018.02.024] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 02/22/2018] [Accepted: 02/26/2018] [Indexed: 11/19/2022]
Abstract
Recent years have seen cytoskeleton dynamics emerging as a key player in axon regeneration. The cytoskeleton, in particular microtubules and actin, ensures the growth of neuronal processes and maintains the singular, highly polarized shape of neurons. Following injury, adult central axons are tipped by a dystrophic structure, the retraction bulb, which prevents their regeneration. Abnormal cytoskeleton dynamics are responsible for the formation of this growth-incompetent structure but pharmacologically modulating cytoskeleton dynamics of injured axons can transform this structure into a growth-competent growth cone. The cytoskeleton also drives the migration of scar-forming cells after an injury. Targeting its dynamics modifies the composition of the inhibitory environment formed by scar tissue and renders it more permissive for regenerating axons. Hence, cytoskeleton dynamics represent an appealing target to promote axon regeneration. As some of cytoskeleton-targeting drugs are used in the clinics for other purposes, they hold the promise to be used as a basis for a regenerative therapy after a spinal cord injury.
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Affiliation(s)
- Oriane Blanquie
- Laboratory for Axon Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Strasse 27, 53127 Bonn, Germany.
| | - Frank Bradke
- Laboratory for Axon Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Strasse 27, 53127 Bonn, Germany.
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α-Tubulin Acetyltransferase Is a Novel Target Mediating Neurite Growth Inhibitory Effects of Chondroitin Sulfate Proteoglycans and Myelin-Associated Glycoprotein. eNeuro 2018; 5:eN-NWR-0240-17. [PMID: 29497702 PMCID: PMC5830348 DOI: 10.1523/eneuro.0240-17.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 01/17/2018] [Accepted: 01/18/2018] [Indexed: 12/24/2022] Open
Abstract
Damage to the CNS results in neuronal and axonal degeneration, and subsequent neurological dysfunction. Endogenous repair in the CNS is impeded by inhibitory chemical and physical barriers, such as chondroitin sulfate proteoglycans (CSPGs) and myelin-associated glycoprotein (MAG), which prevent axon regeneration. Previously, it has been demonstrated that the inhibition of axonal histone deacetylase-6 (HDAC6) can promote microtubule α-tubulin acetylation and restore the growth of CSPGs- and MAG-inhibited axons. Since the acetylation of α-tubulin is regulated by two opposing enzymes, HDAC6 (deacetylation) and α-tubulin acetyltransferase-1 (αTAT1; acetylation), we have investigated the regulation of these enzymes downstream of a growth inhibitory signal. Our findings show that exposure of primary mouse cortical neurons to soluble CSPGs and MAG substrates cause an acute and RhoA-kinase-dependent reduction in α-tubulin acetylation and αTAT1 protein levels, without changes to either HDAC6 levels or HDAC6 activity. The CSPGs- and MAG-induced reduction in αTAT1 occurs primarily in the distal and middle regions of neurites and reconstitution of αTAT1, either by Rho-associated kinase (ROCK) inhibition or lentiviral-mediated αTAT1 overexpression, can restore neurite growth. Lastly, we demonstrate that CSPGs and MAG signaling decreases αTAT1 levels posttranscriptionally via a ROCK-dependent increase in αTAT1 protein turnover. Together, these findings define αTAT1 as a novel potential therapeutic target for ameliorating CNS injury characterized by growth inhibitory substrates that are prohibitive to axonal regeneration.
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69
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Zhang L, Qin H, Wu Z, Chen W, Zhang G. Identification of the potential targets for keloid and hypertrophic scar prevention. J DERMATOL TREAT 2018; 29:600-605. [PMID: 29271272 DOI: 10.1080/09546634.2017.1421309] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Lianbo Zhang
- Department of Plastic Surgery, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Haiyan Qin
- Department of Plastic Surgery, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Zhuoxia Wu
- Department of Plastic Surgery, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Wanying Chen
- Department of Plastic Surgery, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Guang Zhang
- Department of Thyroid Surgery, China-Japan Union Hospital of Jilin University, Changchun, China
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70
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Yu P, Pearson CS, Geller HM. Flexible Roles for Proteoglycan Sulfation and Receptor Signaling. Trends Neurosci 2018; 41:47-61. [PMID: 29150096 PMCID: PMC5748001 DOI: 10.1016/j.tins.2017.10.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 10/19/2017] [Accepted: 10/25/2017] [Indexed: 11/25/2022]
Abstract
Proteoglycans (PGs) in the extracellular matrix (ECM) play vital roles in axon growth and navigation, plasticity, and regeneration of injured neurons. Different classes of PGs may support or inhibit cell growth, and their functions are determined in part by highly specific structural features. Among these, the pattern of sulfation on the PG sugar chains is a paramount determinant of a diverse and flexible set of outcomes. Recent studies of PG sulfation illustrate the challenges of attributing biological actions to specific sulfation patterns, and suggest ways in which highly similar molecules may exert opposing effects on neurons. The receptors for PGs, which have yet to be fully characterized, display a similarly nuanced spectrum of effects. Different classes of PG function via overlapping families of receptors and signaling pathways. This enables them to control axon growth and guidance with remarkable specificity, but it poses challenges for determining the precise binding interactions and downstream effects of different PGs and their assorted sulfated epitopes. This review examines existing and emerging evidence for the roles of PG sulfation and receptor interactions in determining how these complex molecules influence neuronal development, growth, and function.
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Affiliation(s)
- Panpan Yu
- Guangdong-Hongkong-Macau Institute of CNS Regeneration; Ministry of Education Joint International Research Laboratory of CNS Regeneration, Jinan University, Guangzhou 510632, China.
| | - Craig S Pearson
- Laboratory of Developmental Neurobiology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA; Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Herbert M Geller
- Laboratory of Developmental Neurobiology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
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71
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Bollaerts I, Veys L, Geeraerts E, Andries L, De Groef L, Buyens T, Salinas-Navarro M, Moons L, Van Hove I. Complementary research models and methods to study axonal regeneration in the vertebrate retinofugal system. Brain Struct Funct 2017; 223:545-567. [DOI: 10.1007/s00429-017-1571-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 11/15/2017] [Indexed: 01/18/2023]
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72
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Wiersma AM, Fouad K, Winship IR. Enhancing Spinal Plasticity Amplifies the Benefits of Rehabilitative Training and Improves Recovery from Stroke. J Neurosci 2017; 37:10983-10997. [PMID: 29025926 PMCID: PMC6596489 DOI: 10.1523/jneurosci.0770-17.2017] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 09/15/2017] [Accepted: 10/01/2017] [Indexed: 12/15/2022] Open
Abstract
The limited recovery that occurs following stroke happens almost entirely in the first weeks postinjury. Moreover, the efficacy of rehabilitative training is limited beyond this narrow time frame. Sprouting of spared corticospinal tract axons in the contralesional spinal cord makes a significant contribution to sensorimotor recovery, but this structural plasticity is also limited to the first few weeks after stroke. Here, we tested the hypothesis that inducing plasticity in the spinal cord during chronic stroke could improve recovery from persistent sensorimotor impairment. We potentiated spinal plasticity during chronic stroke, weeks after the initial ischemic injury, in male Sprague-Dawley rats via intraspinal injections of chondroitinase ABC. Our data show that chondroitinase injections into the contralesional gray matter of the cervical spinal cord administered 28 d after stroke induced significant sprouting of corticospinal axons originating in the peri-infarct cortex. Chondroitinase ABC injection during chronic stroke without additional training resulted in moderate improvements of sensorimotor deficits. Importantly, this therapy dramatically potentiated the efficacy of rehabilitative training delivered during chronic stroke in a skilled forelimb reaching task. These novel data suggest that spinal therapy during chronic stroke can amplify the benefits of delayed rehabilitative training with the potential to reduce permanent disability in stroke survivors.SIGNIFICANCE STATEMENT The brain and spinal cord undergo adaptive rewiring ("plasticity") following stroke. This plasticity allows for partial functional recovery from stroke induced sensorimotor impairments. However, the plasticity that underlies recovery occurs predominantly in the first weeks following stroke, and most stroke survivors are left with permanent disability even after rehabilitation. Using animal models, our data show that removal of plasticity-inhibiting signals in the spinal cord (via intraspinal injections of the enzyme chondroitinase ABC) augments rewiring of circuits connecting the brain to the spinal cord, even weeks after stroke. Moreover, this plasticity can be harnessed by rehabilitative training to significantly promote sensorimotor recovery. Thus, intraspinal therapy may augment rehabilitative training and improve recovery even in individuals living with chronic disability due to stroke.
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Affiliation(s)
| | - Karim Fouad
- Neuroscience and Mental Health Institute
- Faculty of Rehabilitation Medicine, and
| | - Ian R Winship
- Neuroscience and Mental Health Institute,
- Neurochemical Research Unit, Department of Psychiatry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G 2G3, Canada
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73
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Filous AR, Schwab JM. Determinants of Axon Growth, Plasticity, and Regeneration in the Context of Spinal Cord Injury. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 188:53-62. [PMID: 29030051 DOI: 10.1016/j.ajpath.2017.09.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 09/15/2017] [Accepted: 09/21/2017] [Indexed: 12/30/2022]
Abstract
The mechanisms that underlie recovery after injury of the central nervous system have rarely been definitively established. Axon regrowth remains the major prerequisite for plasticity, regeneration, circuit formation, and eventually functional recovery. The attributed functional relevance of axon regrowth, however, will depend on several subsequent conditional neurobiological modifications, including myelination and synapse formation, but also pruning of aberrant connectivity. Despite the ability to revamp axon outgrowth by altering an increasing number of extracellular and intracellular targets, disentangling which axons are responsible for the recovery of function from those that are functionally silent, or even contributing to aberrant functions, represents a pertinent void in our understanding, challenging the intuitive translational link between anatomical and functional regeneration. Anatomic hallmarks of regeneration are not static and are largely activity dependent. Herein, we survey mechanisms leading to the formation of dystrophic growth cone at the injured axonal tip, the subsequent axonal dieback, and the molecular determinants of axon growth, plasticity, and regeneration in the context of spinal cord injury.
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Affiliation(s)
- Angela R Filous
- Spinal Cord Injury Division, Department of Neurology, The Ohio State University, Wexner Medical Center, Columbus, Ohio.
| | - Jan M Schwab
- Spinal Cord Injury Division, Department of Neurology, The Ohio State University, Wexner Medical Center, Columbus, Ohio; Department of Neuroscience, The Ohio State University, Wexner Medical Center, Columbus, Ohio; Department of Physical Medicine and Rehabilitation, The Ohio State University, Wexner Medical Center, Columbus, Ohio; Center for Brain and Spinal Cord Repair, Spinal Cord Injury Medicine, The Ohio State University, Wexner Medical Center, Columbus, Ohio.
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74
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Sainath R, Armijo-Weingart L, Ketscheck A, Xu Z, Li S, Gallo G. Chondroitin sulfate proteoglycans negatively regulate the positioning of mitochondria and endoplasmic reticulum to distal axons. Dev Neurobiol 2017; 77:1351-1370. [PMID: 28901718 DOI: 10.1002/dneu.22535] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 08/23/2017] [Accepted: 09/08/2017] [Indexed: 12/20/2022]
Abstract
Chondroitin sulfate proteoglycans (CSPGs) are components of the extracellular matrix that inhibit the extension and regeneration of axons. However, the underlying mechanism of action remains poorly understood. Mitochondria and endoplasmic reticulum (ER) are functionally inter-linked organelles important to axon development and maintenance. We report that CSPGs impair the targeting of mitochondria and ER to the growth cones of chicken embryonic sensory axons. The effect of CSPGs on the targeting of mitochondria is blocked by inhibition of the LAR receptor for CSPGs. The regulation of the targeting of mitochondria and ER to the growth cone by CSPGs is due to attenuation of PI3K signaling, which is known to be downstream of LAR receptor activation. Dynactin is a required component of the dynein motor complex that drives the normally occurring retrograde evacuation of mitochondria from growth cones. CSPGs elevate the levels of p150Glu dynactin found in distal axons, and inhibition of the interaction of dynactin with dynein increased axon lengths on CSPGs. CSPGs decreased the membrane potential of mitochondria, and pharmacological inhibition of mitochondria respiration at the growth cone independent of manipulation of mitochondria positioning impaired axon extension. Combined inhibition of dynactin and potentiation of mitochondria respiration further increased axon lengths on CSPGs relative to inhibition of dynactin alone. These data reveal that the regulation of the localization of mitochondria and ER to growth cones is a previously unappreciated aspect of the effects of CSPGs on embryonic axons. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 77: 1351-1370, 2017.
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Affiliation(s)
- Rajiv Sainath
- Department of Anatomy and Cell Biology, Medical Education and Research Building, 3500 North Brad St, Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania, 19140
| | - Lorena Armijo-Weingart
- Department of Anatomy and Cell Biology, Medical Education and Research Building, 3500 North Brad St, Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania, 19140
| | - Andrea Ketscheck
- Department of Anatomy and Cell Biology, Medical Education and Research Building, 3500 North Brad St, Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania, 19140
| | - Zhuxuan Xu
- Department of Anatomy and Cell Biology, Medical Education and Research Building, 3500 North Brad St, Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania, 19140
| | - Shuxin Li
- Department of Anatomy and Cell Biology, Medical Education and Research Building, 3500 North Brad St, Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania, 19140
| | - Gianluca Gallo
- Department of Anatomy and Cell Biology, Medical Education and Research Building, 3500 North Brad St, Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania, 19140
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75
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Pires LR, Lopes CDF, Salvador D, Rocha DN, Pêgo AP. Ibuprofen-loaded fibrous patches-taming inhibition at the spinal cord injury site. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2017; 28:157. [PMID: 28894995 DOI: 10.1007/s10856-017-5967-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 08/19/2017] [Indexed: 06/07/2023]
Abstract
It is now widely accepted that a therapeutic strategy for spinal cord injury (SCI) demands a multi-target approach. Here we propose the use of an easily implantable bilayer polymeric patch based on poly(trimethylene carbonate-co-ε-caprolactone) (P(TMC-CL)) that combines physical guidance cues provided by electrospun aligned fibres and the delivery of ibuprofen, as a mean to reduce the inhibitory environment at the lesion site by taming RhoA activation. Bilayer patches comprised a solvent cast film onto which electrospun aligned fibres have been deposited. Both layers were loaded with ibuprofen. In vitro release (37°C, in phosphate buffered saline) of the drug from the loaded scaffolds under sink condition was found to occur in the first 24 h. The released ibuprofen was shown to retain its bioactivity, as indicated by the reduction of RhoA activation when the neuronal-like cell line ND7/23 was challenged with lysophosphatidic acid. Ibuprofen-loaded P(TMC-CL) bilayer scaffolds were successfully implanted in vivo in a dorsal hemisection rat SCI model mediating the reduction of RhoA activation after 5 days of implantation in comparison to plain P(TMC-CL) scaffolds. Immunohistochemical analysis of the tissue shows βIII tubulin positive cells close to the ibuprofen-loaded patches further supporting the use of this strategy in the context of regeneration after a lesion in the spinal cord.
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Affiliation(s)
- Liliana R Pires
- INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Rua Alfredo Allen 208, Porto, 4200-135, Portugal
- INL- International Iberian Nanotechnology Laboratory, Braga, Portugal
| | - Cátia D F Lopes
- INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Rua Alfredo Allen 208, Porto, 4200-135, Portugal
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Daniela Salvador
- INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Rua Alfredo Allen 208, Porto, 4200-135, Portugal
| | - Daniela N Rocha
- INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Rua Alfredo Allen 208, Porto, 4200-135, Portugal
| | - Ana Paula Pêgo
- INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Rua Alfredo Allen 208, Porto, 4200-135, Portugal.
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.
- Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto (ICBAS), Porto, Portugal.
- Faculdade de Engenharia da Universidade do Porto (FEUP), Porto, Portugal.
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Wang X, Jiao X, Liu Z, Li Y. Crocetin Potentiates Neurite Growth in Hippocampal Neurons and Facilitates Functional Recovery in Rats with Spinal Cord Injury. Neurosci Bull 2017; 33:695-702. [PMID: 28770439 DOI: 10.1007/s12264-017-0157-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Accepted: 05/04/2017] [Indexed: 11/26/2022] Open
Abstract
Crocetin is an ingredient of traditional Chinese medicine and has therapeutic potential in various diseases due to its pharmacological properties, such as neuroprotection, anti-oxidative stress, and anti-inflammation. These properties might benefit the treatment of spinal cord injury. In the present study, we tested the effect of crocetin on neurite growth and sensorimotor dysfunction in a rat model of spinal cord injury. We evaluated the viability of cultured hippocampal neurons with tetrazolium dye and lactate dehydrogenase assays, visualized neurites and axons with antibody staining, and monitored motor and sensorimotor functions in rats with spinal cord injury using the Basso, Beattie, and Bresnahan assay and the contact plantar placement test, respectively, and measured cytokine expression using enzyme-linked immuno-absorbent assays. We found that crocetin (1) did not alter the viability of cultured hippocampal neurons; (2) accelerated neurite growth with preference for the longest process in individual hippocampal neurons; (3) reversed the inhibition of neurite growth by chondroitin sulfate proteoglycan and NogoA; (4) facilitated the recovery of motor and sensorimotor functions after spinal cord injury; and (5) did not inhibit pro-inflammatory responses, but restored the innervation of the descending 5-HT system in injured spinal cord. Crocetin promotes neurite growth and facilitates the recovery of motor and sensorimotor functions after spinal cord injury, likely through repairing neuronal connections.
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Affiliation(s)
- Xiqian Wang
- Orthopaedics Department, The Second Hospital of Shandong University, Jinan, 250012, China
| | - Xiejia Jiao
- Orthopaedics Department, The Second Hospital of Shandong University, Jinan, 250012, China
| | - Zhonghao Liu
- Orthopaedics Department, The Second Hospital of Shandong University, Jinan, 250012, China
| | - Yixin Li
- Imaging Department, The Second Hospital of Shandong University, Jinan, 250012, China.
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77
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Galindo LT, Mundim MTVV, Pinto AS, Chiarantin GMD, Almeida MES, Lamers ML, Horwitz AR, Santos MF, Porcionatto M. Chondroitin Sulfate Impairs Neural Stem Cell Migration Through ROCK Activation. Mol Neurobiol 2017; 55:3185-3195. [PMID: 28477140 PMCID: PMC5842503 DOI: 10.1007/s12035-017-0565-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 04/19/2017] [Indexed: 12/12/2022]
Abstract
Brain injuries such as trauma and stroke lead to glial scar formation by reactive astrocytes which produce and secret axonal outgrowth inhibitors. Chondroitin sulfate proteoglycans (CSPG) constitute a well-known class of extracellular matrix molecules produced at the glial scar and cause growth cone collapse. The CSPG glycosaminoglycan side chains composed of chondroitin sulfate (CS) are responsible for its inhibitory activity on neurite outgrowth and are dependent on RhoA activation. Here, we hypothesize that CSPG also impairs neural stem cell migration inhibiting their penetration into an injury site. We show that DCX+ neuroblasts do not penetrate a CSPG-rich injured area probably due to Nogo receptor activation and RhoA/ROCK signaling pathway as we demonstrate in vitro with neural stem cells cultured as neurospheres and pull-down for RhoA. Furthermore, CS-impaired cell migration in vitro induced the formation of large mature adhesions and altered cell protrusion dynamics. ROCK inhibition restored migration in vitro as well as decreased adhesion size.
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Affiliation(s)
- Layla T Galindo
- Department of Biochemistry, Laboratory of Neurobiology, Universidade Federal de São Paulo, Rua Pedro de Toledo, 669 - 3o andar, São Paulo, SP, 04039-032, Brazil
| | - Mayara T V V Mundim
- Department of Biochemistry, Laboratory of Neurobiology, Universidade Federal de São Paulo, Rua Pedro de Toledo, 669 - 3o andar, São Paulo, SP, 04039-032, Brazil
| | - Agnes S Pinto
- Department of Biochemistry, Laboratory of Neurobiology, Universidade Federal de São Paulo, Rua Pedro de Toledo, 669 - 3o andar, São Paulo, SP, 04039-032, Brazil
| | - Gabrielly M D Chiarantin
- Department of Biochemistry, Laboratory of Neurobiology, Universidade Federal de São Paulo, Rua Pedro de Toledo, 669 - 3o andar, São Paulo, SP, 04039-032, Brazil
| | - Maíra E S Almeida
- Physiopathology Laboratory, Butantan Institute, São Paulo, 05503-900, Brazil
| | - Marcelo L Lamers
- Department of Morphological Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, 90050-170, Brazil
| | - Alan R Horwitz
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, 22903, USA
| | - Marinilce F Santos
- Department of Cell and Developmental Biology, Biomedical Sciences Institute, Universidade de São Paulo, São Paulo, 05508-000, Brazil
| | - Marimelia Porcionatto
- Department of Biochemistry, Laboratory of Neurobiology, Universidade Federal de São Paulo, Rua Pedro de Toledo, 669 - 3o andar, São Paulo, SP, 04039-032, Brazil.
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78
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Wrobel MR, Sundararaghavan HG. Positive and negative cues for modulating neurite dynamics and receptor expression. Biomed Mater 2017; 12:025016. [DOI: 10.1088/1748-605x/aa61d1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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79
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Gwak SJ, Macks C, Jeong DU, Kindy M, Lynn M, Webb K, Lee JS. RhoA knockdown by cationic amphiphilic copolymer/siRhoA polyplexes enhances axonal regeneration in rat spinal cord injury model. Biomaterials 2017; 121:155-166. [PMID: 28088077 DOI: 10.1016/j.biomaterials.2017.01.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/22/2016] [Accepted: 01/02/2017] [Indexed: 01/06/2023]
Abstract
Spinal cord injury (SCI) results in permanent loss of motor and sensory function due to developmentally-related and injured-induced changes in the extrinsic microenvironment and intrinsic neuronal biochemistry that limit plasticity and axonal regeneration. Our long term goal is to develop cationic, amphiphilic copolymers (poly (lactide-co-glycolide)-g-polyethylenimine, PgP) for combinatorial delivery of therapeutic nucleic acids (TNAs) and drugs targeting these different barriers. In this study, we evaluated the ability of PgP to deliver siRNA targeting RhoA, a critical signaling pathway activated by multiple extracellular inhibitors of axonal regeneration. After generation of rat compression SCI model, PgP/siRhoA polyplexes were locally injected into the lesion site. Relative to untreated injury only, PgP/siRhoA polyplexes significantly reduced RhoA mRNA and protein expression for up to 4 weeks post-injury. Histological analysis at 4 weeks post-injury showed that RhoA knockdown was accompanied by reduced apoptosis, cavity size, and astrogliosis and increased axonal regeneration within the lesion site. These studies demonstrate that PgP is an efficient non-viral delivery carrier for therapeutic siRhoA to the injured spinal cord and may be a promising platform for the development of combinatorial TNA/drug therapy.
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Affiliation(s)
- So-Jung Gwak
- Drug Design, Development, and Delivery (4D) Laboratory, Department of Bioengineering, Clemson University, Clemson, SC 29634, USA
| | - Christian Macks
- Drug Design, Development, and Delivery (4D) Laboratory, Department of Bioengineering, Clemson University, Clemson, SC 29634, USA
| | - Da Un Jeong
- Drug Design, Development, and Delivery (4D) Laboratory, Department of Bioengineering, Clemson University, Clemson, SC 29634, USA
| | - Mark Kindy
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL 33612, USA
| | - Michael Lynn
- Department of Neurosurgery, Greenville Health System, Greenville, SC 29615, USA
| | - Ken Webb
- Drug Design, Development, and Delivery (4D) Laboratory, Department of Bioengineering, Clemson University, Clemson, SC 29634, USA
| | - Jeoung Soo Lee
- Drug Design, Development, and Delivery (4D) Laboratory, Department of Bioengineering, Clemson University, Clemson, SC 29634, USA.
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80
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Min YJ, Ding LLQ, Cheng LH, Xiao WP, He XW, Zhang H, Min ZY, Pei J. Effect of electroacupuncture on the mRNA and protein expression of Rho-A and Rho-associated kinase II in spinal cord injury rats. Neural Regen Res 2017; 12:276-282. [PMID: 28400811 PMCID: PMC5361513 DOI: 10.4103/1673-5374.200811] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Electroacupuncture is beneficial for the recovery of spinal cord injury, but the underlying mechanism is unclear. The Rho/Rho-associated kinase (ROCK) signaling pathway regulates the actin cytoskeleton by controlling the adhesive and migratory behaviors of cells that could inhibit neurite regrowth after neural injury and consequently hinder the recovery from spinal cord injury. Therefore, we hypothesized electroacupuncture could affect the Rho/ROCK signaling pathway to promote the recovery of spinal cord injury. In our experiments, the spinal cord injury in adult Sprague-Dawley rats was caused by an impact device. Those rats were subjected to electroacupuncture at Yaoyangguan (GV3), Dazhui (GV14), Zusanli (ST36) and Ciliao (BL32) and/or monosialoganglioside treatment. Behavioral scores revealed that the hindlimb motor functions improved with those treatments. Real-time quantitative polymerase chain reaction, fluorescence in situ hybridization and western blot assay showed that electroacupuncture suppressed the mRNA and protein expression of Rho-A and Rho-associated kinase II (ROCKII) of injured spinal cord. Although monosialoganglioside promoted the recovery of hindlimb motor function, monosialoganglioside did not affect the expression of Rho-A and ROCKII. However, electroacupuncture combined with monosialoganglioside did not further improve the motor function or suppress the expression of Rho-A and ROCKII. Our data suggested that the electroacupuncture could specifically inhibit the activation of the Rho/ROCK signaling pathway thus partially contributing to the repair of injured spinal cord. Monosialoganglioside could promote the motor function but did not suppress expression of RhoA and ROCKII. There was no synergistic effect of electroacupuncture combined with monosialoganglioside.
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Affiliation(s)
- You-Jiang Min
- Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi Province, China
| | - Li-Li-Qiang Ding
- Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi Province, China; Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Li-Hong Cheng
- Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi Province, China
| | - Wei-Ping Xiao
- Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi Province, China
| | - Xing-Wei He
- Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi Province, China
| | - Hui Zhang
- Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi Province, China
| | - Zhi-Yun Min
- Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi Province, China
| | - Jia Pei
- Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi Province, China
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81
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Dell'Anno MT, Strittmatter SM. Rewiring the spinal cord: Direct and indirect strategies. Neurosci Lett 2016; 652:25-34. [PMID: 28007647 DOI: 10.1016/j.neulet.2016.12.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 11/15/2016] [Accepted: 12/02/2016] [Indexed: 12/23/2022]
Abstract
Spinal cord injury is currently incurable. Treatment is limited to minimizing secondary complications and maximizing residual function by rehabilitation. Neurologic recovery is prevented by the poor intrinsic regenerative capacity of neurons in the adult central nervous system and by the presence of growth inhibitors in the adult brain and spinal cord. Here we identify three approaches to rewire the spinal cord after injury: axonal regeneration (direct endogenous reconnection), axonal sprouting (indirect endogenous reconnection) and neural stem cell transplantation (indirect exogenous reconnection). Regeneration and sprouting of axonal fibers can be both enhanced through the neutralization of myelin- and extracellular matrix-associated inhibitors described in the first part of this review. Alternatively, in the second part we focus on the formation of a novel circuit through the grafting of neural stem cells in the lesion site. Transplanted neural stem cells differentiate in vivo into neurons and glial cells which form an intermediate station between the rostral and caudal segment of the recipient spinal cord. In particular, here we describe how neural stem cells-derived neurons are endowed with the ability to extend long-distance axons to regain the transmission of motor and sensory information.
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Affiliation(s)
- Maria Teresa Dell'Anno
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Stephen M Strittmatter
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06536, USA.
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82
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Batty NJ, Fenrich KK, Fouad K. The role of cAMP and its downstream targets in neurite growth in the adult nervous system. Neurosci Lett 2016; 652:56-63. [PMID: 27989572 DOI: 10.1016/j.neulet.2016.12.033] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 12/13/2016] [Accepted: 12/14/2016] [Indexed: 01/23/2023]
Abstract
Injured neurons in the adult mammalian central nervous system (CNS) have a very limited capacity for axonal regeneration and neurite outgrowth. This inability to grow new axons or to regrow injured axons is due to the presence of molecules that inhibit axonal growth, and age related changes in the neuron's innate growth capabilities. Available levels of cAMP are thought to have an important role in linking both of these factors. Elevated levels of cAMP in the developing nervous system are important for the guidance and stability of growth cones. As the nervous system matures, cAMP levels decline and the growth promoting effects of cAMP diminish. It has frequently been demonstrated that increasing neuronal cAMP can enhance neurite growth and regeneration. Some methods used to increase cAMP include administration of cAMP agonists, conditioning lesions, or electrical stimulation. Furthermore, it has been proposed that multiple stages of cAMP induced growth exist, one directly caused by its downstream effector Protein Kinase A (PKA) and one caused by the eventual upregulation of gene transcription. Although the role cAMP in promoting axon growth is well accepted, the downstream pathways that mediate cAMP-mediated axonal growth are less clear. This is partly because various key studies that explored the link between PKA and axonal outgrowth relied on the PKA inhibitors KT5720 and H89. More recent studies have shown that both of these drugs are less specific than initially thought and can inhibit a number of other signalling molecules including the Exchange Protein Activated by cAMP (EPAC). Consequently, it has recently been shown that a number of intracellular signalling pathways previously attributed to PKA can now be attributed solely to activation of EPAC specific pathways, or the simultaneous co-activation of PKA and EPAC specific pathways. These new studies open the door to new potential treatments for repairing the injured spinal cord.
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Affiliation(s)
- Nicholas J Batty
- Neuroscience and Mental Health Institute, 3-88 Corbett Hall, University of Alberta, Edmonton, AB T6E 2G4, Canada
| | - Keith K Fenrich
- Neuroscience and Mental Health Institute, 3-88 Corbett Hall, University of Alberta, Edmonton, AB T6E 2G4, Canada; Department of Physical Therapy, 3-88 Corbett Hall, University of Alberta, Edmonton, AB T6E 2G4, Canada
| | - Karim Fouad
- Neuroscience and Mental Health Institute, 3-88 Corbett Hall, University of Alberta, Edmonton, AB T6E 2G4, Canada; Department of Physical Therapy, 3-88 Corbett Hall, University of Alberta, Edmonton, AB T6E 2G4, Canada.
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83
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Hu J, Zhang G, Rodemer W, Jin LQ, Shifman M, Selzer ME. The role of RhoA in retrograde neuronal death and axon regeneration after spinal cord injury. Neurobiol Dis 2016; 98:25-35. [PMID: 27888137 DOI: 10.1016/j.nbd.2016.11.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 10/24/2016] [Accepted: 11/20/2016] [Indexed: 01/13/2023] Open
Abstract
Paralysis following spinal cord injury (SCI) is due to interruption of axons and their failure to regenerate. It has been suggested that the small GTPase RhoA may be an intracellular signaling convergence point for several types of growth-inhibiting extracellular molecules. Even if this is true in vitro, it is not clear from studies in mammalian SCI, whether the effects of RhoA manipulations on axon growth in vivo are due to a RhoA-mediated inhibition of true regeneration or only of collateral sprouting from spared axons, since work on SCI generally is performed with partial injury models. RhoA also has been implicated in local neuronal apoptosis after SCI, but whether this reflects an effect on axotomy-induced cell death or an effect on other pathological mechanisms is not known. In order to resolve these ambiguities, we studied the effects of RhoA knockdown in the sea lamprey central nervous system (CNS), where after complete spinal cord transection (TX), robust but incomplete regeneration of large axons belonging to individually identified reticulospinal (RS) neurons occurs, and where some RS neurons show unambiguous delayed retrograde apoptosis after axotomy. RhoA protein was detected in neurons and axons of the lamprey brain and spinal cord, and its expression was increased post-TX. Knockdown of RhoA in vivo by retrogradely-delivered morpholino antisense oligonucleotides (MOs) to the RS neurons significantly reduced retrograde apoptosis signaling in identified RS neurons post-SCI, as indicated by Fluorochrome Labeled Inhibitor of Caspases (FLICA) in brain wholemounts. In individual RS neurons, the reduction of caspase activation by RhoA knockdown began at 2weeks post-TX and was still seen at 8weeks. RhoA knockdown slowed axon retraction and possibly increased early axon regeneration in the proximal stump. The number of axons regenerating beyond the lesion more than 5mm at 10weeks post-TX also was increased. Thus RhoA knockdown both enhanced true axon regeneration and inhibited retrograde apoptosis signaling after SCI.
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Affiliation(s)
- Jianli Hu
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Lewis Katz School of Medicine at Temple University, 3500 North Broad Street, Philadelphia, PA 19140, USA
| | - Guixin Zhang
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Lewis Katz School of Medicine at Temple University, 3500 North Broad Street, Philadelphia, PA 19140, USA
| | - William Rodemer
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Lewis Katz School of Medicine at Temple University, 3500 North Broad Street, Philadelphia, PA 19140, USA
| | - Li-Qing Jin
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Lewis Katz School of Medicine at Temple University, 3500 North Broad Street, Philadelphia, PA 19140, USA
| | - Michael Shifman
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Lewis Katz School of Medicine at Temple University, 3500 North Broad Street, Philadelphia, PA 19140, USA
| | - Michael E Selzer
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Lewis Katz School of Medicine at Temple University, 3500 North Broad Street, Philadelphia, PA 19140, USA; Dept. of Neurology, Lewis Katz School of Medicine at Temple University, 3500 North Broad Street, Philadelphia, PA 19140, USA.
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84
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Ohtake Y, Wong D, Abdul-Muneer PM, Selzer ME, Li S. Two PTP receptors mediate CSPG inhibition by convergent and divergent signaling pathways in neurons. Sci Rep 2016; 6:37152. [PMID: 27849007 PMCID: PMC5111048 DOI: 10.1038/srep37152] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 10/25/2016] [Indexed: 01/29/2023] Open
Abstract
Receptor protein tyrosine phosphatase σ (PTPσ) and its subfamily member LAR act as transmembrane receptors that mediate growth inhibition of chondroitin sulfate proteoglycans (CSPGs). Inhibition of either receptor increases axon growth into and beyond scar tissues after CNS injury. However, it is unclear why neurons express two similar CSPG receptors, nor whether they use the same or different intracellular pathways. We have now studied the signaling pathways of these two receptors using N2A cells and primary neurons derived from knockout mice. We demonstrate that both receptors share certain signaling pathways (RhoA, Akt and Erk), but also use distinct signals to mediate CSPG actions. Activation of PTPσ by CSPGs selectively inactivated CRMP2, APC, S6 kinase and CREB. By contrast LAR activation inactivated PKCζ, cofilin and LKB1. For the first time, we propose a model of the signaling pathways downstream of these two CSPG receptors. We also demonstrate that deleting both receptors exhibits additive enhancement of axon growth in adult neuronal cultures in vitro. Our findings elucidate the novel downstream pathways of CSPGs and suggest potential synergy of blocking their two PTP receptors.
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Affiliation(s)
- Yosuke Ohtake
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
- Department of Anatomy and Cell Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Daniella Wong
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - P. M. Abdul-Muneer
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
- Department of Anatomy and Cell Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Michael E. Selzer
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
- Department of Neurology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Shuxin Li
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
- Department of Anatomy and Cell Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
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85
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Sengupta MB, Saha S, Mohanty PK, Mukhopadhyay KK, Mukhopadhyay D. Increased expression of ApoA1 after neuronal injury may be beneficial for healing. Mol Cell Biochem 2016; 424:45-55. [PMID: 27734225 DOI: 10.1007/s11010-016-2841-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 10/06/2016] [Indexed: 01/24/2023]
Abstract
ApoA1 is a player in reverse cholesterol transport that initiates multiple cellular pathways on binding to its receptor ABCA1. Its relation to neuronal injury is however unclear. We found ApoA1 to be increasingly abundant at a later time point in the secondary phase of traumatic spinal cord injury. In a cellular injury model of neuroblastoma, ApoA1 showed an initial diminished expression after infliction of injury, which sharply increased thereafter. Subsequently, ApoA1 was shown to alter wound healing dynamics in neuroblastoma injury model. It was observed that an initial lag in scratch wound closure was followed by rapid healing in the ApoA1 treatment group. Activation of ERK pathway and Actin polymerisation by ApoA1 corroborated its role in healing after neuronal injury. We propose that ApoA1 is increasingly expressed and secreted as a delayed response to neuronal injury, and this is a self-protecting mechanism of the injured system.
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Affiliation(s)
- Mohor B Sengupta
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, 700064, India
| | - Suparna Saha
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, 700064, India
| | - Pradeep K Mohanty
- Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, 700064, India
| | - Kiran K Mukhopadhyay
- Department of Orthopaedic Surgery, Nil Ratan Sircar Medical College and Hospital, 138 AJC Bose Road, Kolkata, 700014, India
| | - Debashis Mukhopadhyay
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, 700064, India.
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86
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Cekanaviciute E, Buckwalter MS. Astrocytes: Integrative Regulators of Neuroinflammation in Stroke and Other Neurological Diseases. Neurotherapeutics 2016; 13:685-701. [PMID: 27677607 PMCID: PMC5081110 DOI: 10.1007/s13311-016-0477-8] [Citation(s) in RCA: 130] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Astrocytes regulate neuroinflammatory responses after stroke and in other neurological diseases. Although not all astrocytic responses reduce inflammation, their predominant function is to protect the brain by driving the system back to homeostasis after injury. They receive multidimensional signals within the central nervous system and between the brain and the systemic circulation. Processing this information allows astrocytes to regulate synapse formation and maintenance, cerebral blood flow, and blood-brain barrier integrity. Similarly, in response to stroke and other central nervous system disorders, astrocytes detect and integrate signals of neuronal damage and inflammation to regulate the neuroinflammatory response. Two direct regulatory mechanisms in the astrocyte arsenal are the ability to form both physical and molecular barriers that seal the injury site and localize the neuroinflammatory response. Astrocytes also indirectly regulate the inflammatory response by affecting neuronal health during the acute injury and axonal regrowth. This ability to regulate the location and degree of neuroinflammation after injury, combined with the long time course of neuroinflammation, makes astrocytic signaling pathways promising targets for therapies.
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Affiliation(s)
- Egle Cekanaviciute
- Department of Neurology and Neurological Sciences, Stanford Medical School, Stanford, CA, 94305, USA
| | - Marion S Buckwalter
- Department of Neurology and Neurological Sciences, Stanford Medical School, Stanford, CA, 94305, USA.
- Department of Neurosurgery, Stanford Medical School, Stanford, CA, 94305, USA.
- Stanford Stroke Center, Stanford Medical School, Stanford, CA, 94305, USA.
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87
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Mooney MA, McWeeney SK, Faraone SV, Hinney A, Hebebrand J, Nigg JT, Wilmot B. Pathway analysis in attention deficit hyperactivity disorder: An ensemble approach. Am J Med Genet B Neuropsychiatr Genet 2016; 171:815-26. [PMID: 27004716 PMCID: PMC4983253 DOI: 10.1002/ajmg.b.32446] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 03/07/2016] [Indexed: 12/21/2022]
Abstract
Despite a wealth of evidence for the role of genetics in attention deficit hyperactivity disorder (ADHD), specific and definitive genetic mechanisms have not been identified. Pathway analyses, a subset of gene-set analyses, extend the knowledge gained from genome-wide association studies (GWAS) by providing functional context for genetic associations. However, there are numerous methods for association testing of gene sets and no real consensus regarding the best approach. The present study applied six pathway analysis methods to identify pathways associated with ADHD in two GWAS datasets from the Psychiatric Genomics Consortium. Methods that utilize genotypes to model pathway-level effects identified more replicable pathway associations than methods using summary statistics. In addition, pathways implicated by more than one method were significantly more likely to replicate. A number of brain-relevant pathways, such as RhoA signaling, glycosaminoglycan biosynthesis, fibroblast growth factor receptor activity, and pathways containing potassium channel genes, were nominally significant by multiple methods in both datasets. These results support previous hypotheses about the role of regulation of neurotransmitter release, neurite outgrowth and axon guidance in contributing to the ADHD phenotype and suggest the value of cross-method convergence in evaluating pathway analysis results. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Michael A. Mooney
- Division of Bioinformatics & Computational Biology, Department of Medical Informatics & Clinical Epidemiology, Oregon Health & Science University, Portland, Oregon,OHSU Knight Cancer Institute, Portland, Oregon
| | - Shannon K. McWeeney
- Division of Bioinformatics & Computational Biology, Department of Medical Informatics & Clinical Epidemiology, Oregon Health & Science University, Portland, Oregon,OHSU Knight Cancer Institute, Portland, Oregon,Oregon Clinical and Translational Research Institute, Portland, Oregon
| | - Stephen V. Faraone
- Departments of Psychiatry and Neuroscience & Physiology, State University of New York, Syracuse, New York,K.G. Jebsen Centre for Neuropsychiatric Disorders, Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Anke Hinney
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Johannes Hebebrand
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | | | | | - Joel T. Nigg
- Division of Psychology, Department of Psychiatry, Oregon Health & Science University, Portland, Oregon,Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon
| | - Beth Wilmot
- Division of Bioinformatics & Computational Biology, Department of Medical Informatics & Clinical Epidemiology, Oregon Health & Science University, Portland, Oregon,OHSU Knight Cancer Institute, Portland, Oregon,Oregon Clinical and Translational Research Institute, Portland, Oregon,Correspondence to: Beth Wilmot, Ph.D., Division of Bioinformatics & Computational Biology, Department of Medical Informatics & Clinical Epidemiology, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Mail code: CR145, Portland, OR 97239.
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88
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Barber A, Farmer K, Martin KR, Smith PD. Retinal regeneration mechanisms linked to multiple cancer molecules: A therapeutic conundrum. Prog Retin Eye Res 2016; 56:19-31. [PMID: 27586058 DOI: 10.1016/j.preteyeres.2016.08.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 03/06/2016] [Accepted: 03/07/2016] [Indexed: 11/26/2022]
Abstract
Over the last decade, a large number of research articles have been published demonstrating regeneration and/or neuroprotection of retinal ganglion cells following manipulation of specific genetic and molecular targets. Interestingly, of the targets that have been identified to promote repair following visual system damage, many are genes known to be mutated in different types of cancer. This review explores recent literature on the potential for modulating cancer genes as a therapeutic strategy for visual system repair and looks at the potential clinical challenges associated with implementing this type of therapy. We also discuss signalling mechanisms that have been implicated in cancer and consider how similar mechanisms may improve axonal regeneration in the optic nerve.
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Affiliation(s)
- Amanda Barber
- John van Geest Centre for Brain Repair, University of Cambridge, UK
| | - Kyle Farmer
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Keith R Martin
- John van Geest Centre for Brain Repair, University of Cambridge, UK; Medical Research Council - Wellcome Trust Cambridge Stem Cell Institute, Cambridge, UK; Cambridge NIHR Biomedical Research Centre, Cambridge, UK
| | - Patrice D Smith
- John van Geest Centre for Brain Repair, University of Cambridge, UK; Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada.
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89
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Cheah M, Andrews MR, Chew DJ, Moloney EB, Verhaagen J, Fässler R, Fawcett JW. Expression of an Activated Integrin Promotes Long-Distance Sensory Axon Regeneration in the Spinal Cord. J Neurosci 2016; 36:7283-97. [PMID: 27383601 PMCID: PMC4938867 DOI: 10.1523/jneurosci.0901-16.2016] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/05/2016] [Accepted: 05/30/2016] [Indexed: 01/01/2023] Open
Abstract
UNLABELLED After CNS injury, axon regeneration is blocked by an inhibitory environment consisting of the highly upregulated tenascin-C and chondroitin sulfate proteoglycans (CSPGs). Tenascin-C promotes growth of axons if they express a tenascin-binding integrin, particularly α9β1. Additionally, integrins can be inactivated by CSPGs, and this inhibition can be overcome by the presence of a β1-binding integrin activator, kindlin-1. We examined the synergistic effect of α9 integrin and kindlin-1 on sensory axon regeneration in adult rat spinal cord after dorsal root crush and adeno-associated virus transgene expression in dorsal root ganglia. After 12 weeks, axons from C6-C7 dorsal root ganglia regenerated through the tenascin-C-rich dorsal root entry zone into the dorsal column up to C1 level and above (>25 mm axon length) through a normal pathway. Animals also showed anatomical and electrophysiological evidence of reconnection to the dorsal horn and behavioral recovery in mechanical pressure, thermal pain, and ladder-walking tasks. Expression of α9 integrin or kindlin-1 alone promoted much less regeneration and recovery. SIGNIFICANCE STATEMENT The study demonstrates that long-distance sensory axon regeneration over a normal pathway and with sensory and sensory-motor recovery can be achieved. This was achieved by expressing an integrin that recognizes tenascin-C, one of the components of glial scar tissue, and an integrin activator. This enabled extensive long-distance (>25 mm) regeneration of both myelinated and unmyelinated sensory axons with topographically correct connections in the spinal cord. The extent of growth and recovery we have seen would probably be clinically significant. Restoration of sensation to hands, perineum, and genitalia would be a significant improvement for a spinal cord-injured patient.
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Affiliation(s)
- Menghon Cheah
- John van Geest Centre for Brain Repair, University of Cambridge, Cambridge CB2 0PY, United Kingdom
| | - Melissa R Andrews
- School of Medicine, University of St. Andrews, St. Andrews KY16 9TF, United Kingdom,
| | - Daniel J Chew
- John van Geest Centre for Brain Repair, University of Cambridge, Cambridge CB2 0PY, United Kingdom
| | - Elizabeth B Moloney
- Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, 1105 BA, Amsterdam, The Netherlands, and
| | - Joost Verhaagen
- Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, 1105 BA, Amsterdam, The Netherlands, and
| | - Reinhard Fässler
- Department of Molecular Medicine, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - James W Fawcett
- John van Geest Centre for Brain Repair, University of Cambridge, Cambridge CB2 0PY, United Kingdom,
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90
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Yan H, Zhu X, Xie J, Zhao Y, Liu X. β-amyloid increases neurocan expression through regulating Sox9 in astrocytes: A potential relationship between Sox9 and chondroitin sulfate proteoglycans in Alzheimer's disease. Brain Res 2016; 1646:377-383. [PMID: 27317830 DOI: 10.1016/j.brainres.2016.06.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 06/04/2016] [Accepted: 06/07/2016] [Indexed: 02/05/2023]
Abstract
OBJECTIVE This study aimed to investigate whether β-amyloid (Aβ) was able to enhance neurocan expression in a Sox9 dependent manner in astrocytes. METHODS AND MATERIALS Astrocytes were incubated with Aβ at different concentrations, the expression of Sox9 and neurocan was detected by Western blot assay. Meanwhile, the viability and proliferation of astrocytes were assessed by MTT assay. Then, the Sox9 expression was silenced, and the expression of Sox9 and neurocan was examined. RESULTS After incubation with Aβ, the viability of astrocytes was increased regardless silencing of Sox9 (all P<0.05). The proliferation of astrocytes was also gradually increased with the increase in the time of Aβ incubation (all P<0.05). With the increase in Aβ concentration, the expression of Sox9 and neurocan was also increased (all P<0.05). However, after silencing of Sox9 expression, the neurocan expression was significantly reduced as compared to control group and scra-siRNA group (all P<0.05). CONCLUSION Our study shows the viability and proliferation of astrocytes are significantly increased by Aβ in a dose dependent manner. Moreover, Aβ may effectively up-regulate the neurocan expression via regulating Sox9.
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Affiliation(s)
- Han Yan
- Department of Neurology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, PR China
| | - Xiaolong Zhu
- Department of Neurology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, PR China
| | - Junchao Xie
- Department of Neurology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, PR China
| | - Yanxin Zhao
- Department of Neurology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, PR China.
| | - Xueyuan Liu
- Department of Neurology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, PR China.
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91
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Rao SNR, Pearse DD. Regulating Axonal Responses to Injury: The Intersection between Signaling Pathways Involved in Axon Myelination and The Inhibition of Axon Regeneration. Front Mol Neurosci 2016; 9:33. [PMID: 27375427 PMCID: PMC4896923 DOI: 10.3389/fnmol.2016.00033] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 05/02/2016] [Indexed: 01/06/2023] Open
Abstract
Following spinal cord injury (SCI), a multitude of intrinsic and extrinsic factors adversely affect the gene programs that govern the expression of regeneration-associated genes (RAGs) and the production of a diversity of extracellular matrix molecules (ECM). Insufficient RAG expression in the injured neuron and the presence of inhibitory ECM at the lesion, leads to structural alterations in the axon that perturb the growth machinery, or form an extraneous barrier to axonal regeneration, respectively. Here, the role of myelin, both intact and debris, in antagonizing axon regeneration has been the focus of numerous investigations. These studies have employed antagonizing antibodies and knockout animals to examine how the growth cone of the re-growing axon responds to the presence of myelin and myelin-associated inhibitors (MAIs) within the lesion environment and caudal spinal cord. However, less attention has been placed on how the myelination of the axon after SCI, whether by endogenous glia or exogenously implanted glia, may alter axon regeneration. Here, we examine the intersection between intracellular signaling pathways in neurons and glia that are involved in axon myelination and axon growth, to provide greater insight into how interrogating this complex network of molecular interactions may lead to new therapeutics targeting SCI.
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Affiliation(s)
- Sudheendra N R Rao
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine Miami, FL, USA
| | - Damien D Pearse
- The Miami Project to Cure Paralysis, University of Miami Miller School of MedicineMiami, FL, USA; The Department of Neurological Surgery, University of Miami Miller School of MedicineMiami, FL, USA; The Neuroscience Program, University of Miami Miller School of MedicineMiami, FL, USA; The Interdisciplinary Stem Cell Institute, University of Miami Miller School of MedicineMiami, FL, USA; Bruce W. Carter Department of Veterans Affairs Medical CenterMiami, FL, USA
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92
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Astrocytes Grown in Alvetex(®) Three Dimensional Scaffolds Retain a Non-reactive Phenotype. Neurochem Res 2016; 41:1857-67. [PMID: 27099962 DOI: 10.1007/s11064-016-1911-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 05/21/2015] [Accepted: 06/22/2015] [Indexed: 12/30/2022]
Abstract
Protocols which permit the extraction of primary astrocytes from either embryonic or postnatal mice are well established however astrocytes in culture are different to those in the mature CNS. Three dimensional (3D) cultures, using a variety of scaffolds may enable better phenotypic properties to be developed in culture. We present data from embryonic (E15) and postnatal (P4) murine primary cortical astrocytes grown on coated coverslips or a 3D polystyrene scaffold, Alvetex. Growth of both embryonic and postnatal primary astrocytes in the 3D scaffold changed astrocyte morphology to a mature, protoplasmic phenotype. Embryonic-derived astrocytes in 3D expressed markers of mature astrocytes, namely the glutamate transporter GLT-1 with low levels of the chondroitin sulphate proteoglycans, NG2 and SMC3. Embryonic astrocytes derived in 3D show lower levels of markers of reactive astrocytes, namely GFAP and mRNA levels of LCN2, PTX3, Serpina3n and Cx43. Postnatal-derived astrocytes show few protein changes between 2D and 3D conditions. Our data shows that Alvetex is a suitable scaffold for growth of astrocytes, and with appropriate choice of cells allows the maintenance of astrocytes with the properties of mature cells and a non-reactive phenotype.
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93
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Abstract
A spinal cord injury refers to an injury to the spinal cord that is caused by a trauma instead of diseases. Spinal cord injury includes a primary mechanical injury and a much more complex secondary injury process involving inflammation, oxidation, excitotoxicity, and cell death. During the secondary injury, many signal pathways are activated and play important roles in mediating the pathogenesis of spinal cord injury. Among them, the RhoA/Rho kinase pathway plays a particular role in mediating spinal degeneration and regeneration. In this review, we will discuss the role and mechanism of RhoA/Rho kinase-mediated spinal cord pathogenesis, as well as the potential of targeting RhoA/Rho kinase as a strategy for promoting both neuroprotection and axonal regeneration.
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Affiliation(s)
- Xiangbing Wu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN, USA; Goodman Campbell Brain and Spine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Xiao-Ming Xu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Anatomy & Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN, USA; Goodman Campbell Brain and Spine, Indiana University School of Medicine, Indianapolis, IN, USA
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94
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Abeysinghe HCS, Phillips EL, Chin-Cheng H, Beart PM, Roulston CL. Modulating Astrocyte Transition after Stroke to Promote Brain Rescue and Functional Recovery: Emerging Targets Include Rho Kinase. Int J Mol Sci 2016; 17:288. [PMID: 26927079 PMCID: PMC4813152 DOI: 10.3390/ijms17030288] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/26/2016] [Accepted: 02/05/2016] [Indexed: 01/13/2023] Open
Abstract
Stroke is a common and serious condition, with few therapies. Whilst previous focus has been directed towards biochemical events within neurons, none have successfully prevented the progression of injury that occurs in the acute phase. New targeted treatments that promote recovery after stroke might be a better strategy and are desperately needed for the majority of stroke survivors. Cells comprising the neurovascular unit, including blood vessels and astrocytes, present an alternative target for supporting brain rescue and recovery in the late phase of stroke, since alteration in the unit also occurs in regions outside of the lesion. One of the major changes in the unit involves extensive morphological transition of astrocytes resulting in altered energy metabolism, decreased glutamate reuptake and recycling, and retraction of astrocyte end feed from both blood vessels and neurons. Whilst globally inhibiting transitional change in astrocytes after stroke is reported to result in further damage and functional loss, we discuss the available evidence to suggest that the transitional activation of astrocytes after stroke can be modulated for improved outcomes. In particular, we review the role of Rho-kinase (ROCK) in reactive gliosis and show that inhibiting ROCK after stroke results in reduced scar formation and improved functional recovery.
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Affiliation(s)
- Hima Charika S Abeysinghe
- Neurotrauma Research, Department of Medicine, St Vincent's Campus, University of Melbourne, Parkville, VIC 3065, Australia.
- Department of Surgery, St Vincent's Campus, University of Melbourne, Parkville, VIC 3065, Australia.
| | - Ellie L Phillips
- Department of Biochemistry and Molecular Biology, Bio21 Insitute, University of Melbourne, Parkville, VIC 3010, Australia.
| | - Heung Chin-Cheng
- Department of Biochemistry and Molecular Biology, Bio21 Insitute, University of Melbourne, Parkville, VIC 3010, Australia.
| | - Philip M Beart
- The Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, Parkville, VIC 3010, Australia.
| | - Carli L Roulston
- Neurotrauma Research, Department of Medicine, St Vincent's Campus, University of Melbourne, Parkville, VIC 3065, Australia.
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95
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Koenig B, Pape D, Chao O, Bauer J, Grimpe B. Long term study of deoxyribozyme administration to XT-1 mRNA promotes corticospinal tract regeneration and improves behavioral outcome after spinal cord injury. Exp Neurol 2016; 276:51-8. [PMID: 26428904 DOI: 10.1016/j.expneurol.2015.09.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 09/18/2015] [Accepted: 09/26/2015] [Indexed: 11/25/2022]
Abstract
Spinal cord injury (SCI) affects approximately 3 million people around the world, who are desperately awaiting treatment. The pressing need for the development of therapeutics has spurred medical research for decades. To respond to this pressing need, our group developed a potential therapeutic to reduce the presence of proteoglycans at the injury site after acutely traumatizing the spinal cord of rats. With the aid of a DNA enzyme against the mRNA of xylosyltransferase-1 (DNAXT-1as) we adjourn the glycosylation and prevent the assembly of the proteoglycan core protein into the extracellular matrix. Hence, endogenous repair is strengthened due to the allocation of a more growth permissive environment around the lesion site. Here, we present data on a long term study of animals with a dorsal hemisection treated with DNAXT-1as, DNAXT-1mb (control DNA enzyme) or PBS via osmotic minipumps. After successful digestion of the XT-1 mRNA shown by qPCR we observed an overall behavioral improvement of DNAXT-1as treated rats at 8, 10 and 14 weeks after insult to the spine compared to the control animals. This is accompanied by the growth of the cortical spinal tract (CST) in DNAXT-1as treated animals after a 19 week survival period. Furthermore, after evaluating the lesion size tissue-protective effects in the DNAXT-1as treated animals compared to DNAXT-1mb and PBS treated rats are revealed. The results yield new insights into the regeneration processes and provide confirmation to involve DNA enzyme administration in future therapeutic strategies to medicate SCI.
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Affiliation(s)
- Brigitte Koenig
- Molecular Neurobiology, Heinrich Heine University, Düsseldorf, 40225, Germany.
| | - Daniel Pape
- Applied Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, 40225, Germany.
| | - Owen Chao
- Center for Behavioral Neuroscience, Heinrich Heine University, Düsseldorf, 40225, Germany.
| | - Jordana Bauer
- Applied Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, 40225, Germany.
| | - Barbara Grimpe
- Applied Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, 40225, Germany; Corresponding author at: Applied Neurobiology, Heinrich Heine University Düsseldorf, Moorenstr. 5, Düsseldorf 40225, Germany..
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96
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Al-Ali H, Beckerman SR, Bixby JL, Lemmon VP. In vitro models of axon regeneration. Exp Neurol 2016; 287:423-434. [PMID: 26826447 DOI: 10.1016/j.expneurol.2016.01.020] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 01/20/2016] [Accepted: 01/25/2016] [Indexed: 12/31/2022]
Abstract
A variety of in vitro models have been developed to understand the mechanisms underlying the regenerative failure of central nervous system (CNS) axons, and to guide pre-clinical development of regeneration-promoting therapeutics. These range from single-cell based assays that typically focus on molecular mechanisms to organotypic assays that aim to recapitulate in vivo behavior. By utilizing a combination of models, researchers can balance the speed, convenience, and mechanistic resolution of simpler models with the biological relevance of more complex models. This review will discuss a number of models that have been used to build our understanding of the molecular mechanisms of CNS axon regeneration.
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Affiliation(s)
- Hassan Al-Ali
- Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Samuel R Beckerman
- Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - John L Bixby
- Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Center for Computational Sciences, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Molecular & Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
| | - Vance P Lemmon
- Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Center for Computational Sciences, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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97
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Al-Ali H, Lemmon VP, Bixby JL. Phenotypic Screening of Small-Molecule Inhibitors: Implications for Therapeutic Discovery and Drug Target Development in Traumatic Brain Injury. Methods Mol Biol 2016; 1462:677-688. [PMID: 27604745 DOI: 10.1007/978-1-4939-3816-2_37] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The inability of central nervous system (CNS) neurons to regenerate damaged axons and dendrites following traumatic brain injury (TBI) creates a substantial obstacle for functional recovery. Apoptotic cell death, deposition of scar tissue, and growth-repressive molecules produced by glia further complicate the problem and make it challenging for re-growing axons to extend across injury sites. To date, there are no approved drugs for the treatment of TBI, accentuating the need for relevant leads. Cell-based and organotypic bioassays can better mimic outcomes within the native CNS microenvironment than target-based screening methods and thus should speed the discovery of therapeutic agents that induce axon or dendrite regeneration. Additionally, when used to screen focused chemical libraries such as small-molecule protein kinase inhibitors, these assays can help elucidate molecular mechanisms involved in neurite outgrowth and regeneration as well as identify novel drug targets. Here, we describe a phenotypic cellular (high content) screening assay that utilizes brain-derived primary neurons for screening small-molecule chemical libraries.
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Affiliation(s)
- Hassan Al-Ali
- Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, 331365, USA
| | - Vance P Lemmon
- Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, 331365, USA
- Center for Computational Science, University of Miami Miller School of Medicine, Miami, FL, 331365, USA
- Departments of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, 331365, USA
| | - John L Bixby
- Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, 331365, USA.
- Center for Computational Science, University of Miami Miller School of Medicine, Miami, FL, 331365, USA.
- Departments of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, 331365, USA.
- Molecular & Cellular Pharmacology, University of Miami Miller School of Medicine, 1400 NW 10th Ave., DT 1205, Miami, FL, 331365, USA.
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98
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van Niekerk EA, Tuszynski MH, Lu P, Dulin JN. Molecular and Cellular Mechanisms of Axonal Regeneration After Spinal Cord Injury. Mol Cell Proteomics 2015; 15:394-408. [PMID: 26695766 DOI: 10.1074/mcp.r115.053751] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Indexed: 12/28/2022] Open
Abstract
Following axotomy, a complex temporal and spatial coordination of molecular events enables regeneration of the peripheral nerve. In contrast, multiple intrinsic and extrinsic factors contribute to the general failure of axonal regeneration in the central nervous system. In this review, we examine the current understanding of differences in protein expression and post-translational modifications, activation of signaling networks, and environmental cues that may underlie the divergent regenerative capacity of central and peripheral axons. We also highlight key experimental strategies to enhance axonal regeneration via modulation of intraneuronal signaling networks and the extracellular milieu. Finally, we explore potential applications of proteomics to fill gaps in the current understanding of molecular mechanisms underlying regeneration, and to provide insight into the development of more effective approaches to promote axonal regeneration following injury to the nervous system.
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Affiliation(s)
- Erna A van Niekerk
- From the ‡Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093;
| | - Mark H Tuszynski
- From the ‡Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093; §Veterans Administration Medical Center, San Diego, CA 92161
| | - Paul Lu
- From the ‡Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093; §Veterans Administration Medical Center, San Diego, CA 92161
| | - Jennifer N Dulin
- From the ‡Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093
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99
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Wiese S, Faissner A. The role of extracellular matrix in spinal cord development. Exp Neurol 2015; 274:90-9. [DOI: 10.1016/j.expneurol.2015.05.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 05/13/2015] [Accepted: 05/25/2015] [Indexed: 01/06/2023]
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100
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Newell-Litwa KA, Horwitz R, Lamers ML. Non-muscle myosin II in disease: mechanisms and therapeutic opportunities. Dis Model Mech 2015; 8:1495-515. [PMID: 26542704 PMCID: PMC4728321 DOI: 10.1242/dmm.022103] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The actin motor protein non-muscle myosin II (NMII) acts as a master regulator of cell morphology, with a role in several essential cellular processes, including cell migration and post-synaptic dendritic spine plasticity in neurons. NMII also generates forces that alter biochemical signaling, by driving changes in interactions between actin-associated proteins that can ultimately regulate gene transcription. In addition to its roles in normal cellular physiology, NMII has recently emerged as a critical regulator of diverse, genetically complex diseases, including neuronal disorders, cancers and vascular disease. In the context of these disorders, NMII regulatory pathways can be directly mutated or indirectly altered by disease-causing mutations. NMII regulatory pathway genes are also increasingly found in disease-associated copy-number variants, particularly in neuronal disorders such as autism and schizophrenia. Furthermore, manipulation of NMII-mediated contractility regulates stem cell pluripotency and differentiation, thus highlighting the key role of NMII-based pharmaceuticals in the clinical success of stem cell therapies. In this Review, we discuss the emerging role of NMII activity and its regulation by kinases and microRNAs in the pathogenesis and prognosis of a diverse range of diseases, including neuronal disorders, cancer and vascular disease. We also address promising clinical applications and limitations of NMII-based inhibitors in the treatment of these diseases and the development of stem-cell-based therapies.
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Affiliation(s)
- Karen A Newell-Litwa
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Rick Horwitz
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Marcelo L Lamers
- Department of Morphological Sciences, Institute of Basic Health Science, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 90610-010, Brazil
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