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Hilton BJ, Griffin JM, Fawcett JW, Bradke F. Neuronal maturation and axon regeneration: unfixing circuitry to enable repair. Nat Rev Neurosci 2024; 25:649-667. [PMID: 39164450 DOI: 10.1038/s41583-024-00849-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2024] [Indexed: 08/22/2024]
Abstract
Mammalian neurons lose the ability to regenerate their central nervous system axons as they mature during embryonic or early postnatal development. Neuronal maturation requires a transformation from a situation in which neuronal components grow and assemble to one in which these components are fixed and involved in the machinery for effective information transmission and computation. To regenerate after injury, neurons need to overcome this fixed state to reactivate their growth programme. A variety of intracellular processes involved in initiating or sustaining neuronal maturation, including the regulation of gene expression, cytoskeletal restructuring and shifts in intracellular trafficking, have been shown to prevent axon regeneration. Understanding these processes will contribute to the identification of targets to promote repair after injury or disease.
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Affiliation(s)
- Brett J Hilton
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada.
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada.
| | - Jarred M Griffin
- Laboratory for Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - James W Fawcett
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, UK.
- Centre for Reconstructive Neuroscience, Institute for Experimental Medicine Czech Academy of Science (CAS), Prague, Czechia.
| | - Frank Bradke
- Laboratory for Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.
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2
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Michel-Flutot P, Cheng L, Thomas SJ, Lisi B, Schwartz H, Lam S, Lyttle M, Jaffe DA, Smith G, Li S, Wright MC, Lepore AC. PTEN inhibition promotes robust growth of bulbospinal respiratory axons and partial recovery of diaphragm function in a chronic model of cervical contusion spinal cord injury. Exp Neurol 2024; 378:114816. [PMID: 38789023 PMCID: PMC11200215 DOI: 10.1016/j.expneurol.2024.114816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 03/25/2024] [Accepted: 05/16/2024] [Indexed: 05/26/2024]
Abstract
High spinal cord injury (SCI) leads to persistent and debilitating compromise in respiratory function. Cervical SCI not only causes the death of phrenic motor neurons (PhMNs) that innervate the diaphragm, but also damages descending respiratory pathways originating in the rostral ventral respiratory group (rVRG) located in the brainstem, resulting in denervation and consequent silencing of spared PhMNs located caudal to injury. It is imperative to determine whether interventions targeting rVRG axon growth and respiratory neural circuit reconnection are efficacious in chronic cervical contusion SCI, given that the vast majority of individuals are chronically-injured and most cases of SCI involve contusion-type damage to the cervical region. We therefore employed a rat model of chronic cervical hemicontusion to test therapeutic manipulations aimed at reconstructing damaged rVRG-PhMN-diaphragm circuitry to achieve recovery of respiratory function. At a chronic time point post-injury, we systemically administered: an antagonist peptide directed against phosphatase and tensin homolog (PTEN), a central inhibitor of neuron-intrinsic axon growth potential; an antagonist peptide directed against receptor-type protein tyrosine phosphatase sigma (PTPσ), another important negative regulator of axon growth capacity; or a combination of these two peptides. PTEN antagonist peptide (PAP4) promoted partial recovery of diaphragm motor activity out to nine months post-injury (though this effect depended on the anesthetic regimen used during recording), while PTPσ peptide did not impact diaphragm function after cervical SCI. Furthermore, PAP4 promoted robust growth of descending bulbospinal rVRG axons caudal to the injury within the denervated portion of the PhMN pool, while PTPσ peptide did not affect rVRG axon growth at this location that is critical to control of diaphragmatic respiratory function. In conclusion, we find that, when PTEN inhibition is targeted at a chronic time point following cervical contusion, our non-invasive PAP4 strategy can successfully promote significant regrowth of damaged respiratory neural circuitry and also partial recovery of diaphragm motor function.
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Affiliation(s)
- Pauline Michel-Flutot
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Lan Cheng
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Samantha J Thomas
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Brianna Lisi
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Harrison Schwartz
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Sandy Lam
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Megan Lyttle
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - David A Jaffe
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - George Smith
- Department of Neuroscience, Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, PA 191405104, USA
| | - Shuxin Li
- Department of Neuroscience, Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, PA 191405104, USA
| | - Megan C Wright
- Department of Biology, Arcadia University, Glenside, PA 19038, USA
| | - Angelo C Lepore
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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3
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Cong M, Li J, Wang L, Liu C, Zheng M, Zhou Q, Du M, Ye X, Feng M, Ye Y, Zhang S, Xu W, Lu Y, Wang C, Xia Y, Xie H, Zhang Y, He Q, Gong L, Gu Y, Sun H, Zhang Q, Zhao J, Ding F, Gu X, Zhou S. MircoRNA-25-3p in skin precursor cell-induced Schwann cell-derived extracellular vesicles promotes axon regeneration by targeting Tgif1. Exp Neurol 2024; 376:114750. [PMID: 38492636 DOI: 10.1016/j.expneurol.2024.114750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 02/20/2024] [Accepted: 03/08/2024] [Indexed: 03/18/2024]
Abstract
Nerve injury often leads to severe dysfunction because of the lack of axon regeneration in adult mammal. Intriguingly a series of extracellular vesicles (EVs) have the obvious ability to accelerate the nerve repair. However, the detailed molecular mechanisms to describe that EVs switch neuron from a transmitter to a regenerative state have not been elucidated. This study elucidated the microRNA (miRNA) expression profiles of two types of EVs that promote nerve regeneration. The functions of these miRNAs were screened in vitro. Among the 12 overlapping miRNAs, miR-25-3p was selected for further analysis as it markedly promoted axon regeneration both in vivo and in vitro. Furthermore, knockdown experiments confirmed that PTEN and Klf4, which are the major inhibitors of axon regeneration, were the direct targets of miR-25-3p in dorsal root ganglion (DRG) neurons. The utilization of luciferase reporter assays and functional tests provided evidence that miR-25-3p enhances axon regeneration by targeting Tgif1. Additionally, miR-25-3p upregulated the phosphorylation of Erk. Furthermore, Rapamycin modulated the expression of miR-25-3p in DRG neurons. Finally, the pro-axon regeneration effects of EVs were confirmed by overexpressing miR-25-3p and Tgif1 knockdown in the optic nerve crush model. Thus, the enrichment of miR-25-3p in EVs suggests that it regulates axon regeneration, proving a potential cell-free treatment strategy for nerve injury.
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Affiliation(s)
- Meng Cong
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu 226001, China
| | - Jiyu Li
- Department of Orthopedic Oncology, Second Affiliated Hospital of Naval Medical University, Shanghai 200003, China
| | - Lijuan Wang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu 226001, China
| | - Chang Liu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu 226001, China
| | - Mengru Zheng
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu 226001, China
| | - Qiang Zhou
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu 226001, China
| | - Mingzhi Du
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu 226001, China
| | - Xinli Ye
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu 226001, China
| | - Min Feng
- Department of Orthopedic Oncology, Second Affiliated Hospital of Naval Medical University, Shanghai 200003, China
| | - Yujiao Ye
- Medical School of Nantong University, Nantong, Jiangsu 226001, China
| | - Shuyu Zhang
- Medical School of Nantong University, Nantong, Jiangsu 226001, China
| | - Wenqing Xu
- Medical School of Nantong University, Nantong, Jiangsu 226001, China
| | - Yi Lu
- Medical School of Nantong University, Nantong, Jiangsu 226001, China
| | - Cheng Wang
- Medical School of Nantong University, Nantong, Jiangsu 226001, China
| | - Yingjie Xia
- Medical School of Nantong University, Nantong, Jiangsu 226001, China
| | - Huimin Xie
- The Affiliated Nantong Stomatological Hospital of Nantong University, Nantong 226007, China
| | - Yide Zhang
- Department of Geriatrics, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu, China
| | - Qianru He
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu 226001, China
| | - Leilei Gong
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu 226001, China
| | - Yun Gu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu 226001, China
| | - Hualin Sun
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu 226001, China
| | - Qi Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu 226001, China
| | - Jian Zhao
- Department of Orthopedic Oncology, Second Affiliated Hospital of Naval Medical University, Shanghai 200003, China.
| | - Fei Ding
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu 226001, China.
| | - Xiaosong Gu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu 226001, China.
| | - Songlin Zhou
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu 226001, China.
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Michel-Flutot P, Cheng L, Thomas SJ, Lisi B, Schwartz H, Lam S, Lyttle M, Jaffe DA, Smith G, Li S, Wright MC, Lepore AC. PTEN inhibition promotes robust growth of bulbospinal respiratory axons and partial recovery of diaphragm function in a chronic model of cervical contusion spinal cord injury. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.10.575021. [PMID: 38260313 PMCID: PMC10802567 DOI: 10.1101/2024.01.10.575021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
High spinal cord injury (SCI) leads to persistent and debilitating compromise in respiratory function. Cervical SCI not only causes the death of phrenic motor neurons (PhMNs) that innervate the diaphragm, but also damages descending respiratory pathways originating in the rostral ventral respiratory group (rVRG) located in the brainstem, resulting in denervation and consequent silencing of spared PhMNs located caudal to injury. It is imperative to determine whether interventions targeting rVRG axon growth and respiratory neural circuit reconnection are efficacious in chronic cervical contusion SCI, given that the vast majority of individuals are chronically-injured and most cases of SCI involve contusion-type damage to the cervical region. We therefore employed a clinically-relevant rat model of chronic cervical hemicontusion to test therapeutic manipulations aimed at reconstructing damaged rVRG-PhMN-diaphragm circuitry to achieve recovery of respiratory function. At a chronic time point post-injury, we systemically administered: an antagonist peptide directed against phosphatase and tensin homolog (PTEN), a central inhibitor of neuron-intrinsic axon growth potential; an antagonist peptide directed against receptor-type protein tyrosine phosphatase sigma (PTPσ), another important negative regulator of axon growth capacity; or a combination of these two peptides. PTEN antagonist peptide (PAP4) promoted partial recovery of diaphragm motor activity out to nine months post-injury, while PTPσ peptide did not impact diaphragm function after cervical SCI. Furthermore, PAP4 promoted robust growth of descending bulbospinal rVRG axons caudal to the injury within the denervated portion of the PhMN pool, while PTPσ peptide did not affect rVRG axon growth at this location that is critical to control of diaphragmatic respiratory function. In conclusion, we find that, when PTEN inhibition is targeted at a chronic time point following cervical contusion that is most relevant to the SCI clinical population, our non-invasive PAP4 strategy can successfully promote significant regrowth of damaged respiratory neural circuitry and also partial recovery of diaphragm motor function. HIGHLIGHTS PTEN antagonist peptide promotes partial diaphragm function recovery in chronic cervical contusion SCI.PTPσ inhibitory peptide does not impact diaphragm function recovery in chronic cervical contusion SCI.PTEN antagonist peptide promotes growth of bulbospinal rVRG axons in chronic cervical contusion SCI.PTPσ peptide does not affect rVRG axon growth in chronic cervical contusion SCI.
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5
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Kim HJ, Saikia JM, Monte KMA, Ha E, Romaus-Sanjurjo D, Sanchez JJ, Moore AX, Hernaiz-Llorens M, Chavez-Martinez CL, Agba CK, Li H, Zhang J, Lusk DT, Cervantes KM, Zheng B. Deep scRNA sequencing reveals a broadly applicable Regeneration Classifier and implicates antioxidant response in corticospinal axon regeneration. Neuron 2023; 111:3953-3969.e5. [PMID: 37848024 PMCID: PMC10843387 DOI: 10.1016/j.neuron.2023.09.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 07/26/2023] [Accepted: 09/15/2023] [Indexed: 10/19/2023]
Abstract
Despite substantial progress in understanding the biology of axon regeneration in the CNS, our ability to promote regeneration of the clinically important corticospinal tract (CST) after spinal cord injury remains limited. To understand regenerative heterogeneity, we conducted patch-based single-cell RNA sequencing on rare regenerating CST neurons at high depth following PTEN and SOCS3 deletion. Supervised classification with Garnett gave rise to a Regeneration Classifier, which can be broadly applied to predict the regenerative potential of diverse neuronal types across developmental stages or after injury. Network analyses highlighted the importance of antioxidant response and mitochondrial biogenesis. Conditional gene deletion validated a role for NFE2L2 (or NRF2), a master regulator of antioxidant response, in CST regeneration. Our data demonstrate a universal transcriptomic signature underlying the regenerative potential of vastly different neuronal populations and illustrate that deep sequencing of only hundreds of phenotypically identified neurons has the power to advance regenerative biology.
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Affiliation(s)
- Hugo J Kim
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Junmi M Saikia
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA; Neurosciences Graduate Program, University of California San Diego, La Jolla, CA, USA USA
| | - Katlyn Marie A Monte
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Eunmi Ha
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Daniel Romaus-Sanjurjo
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Joshua J Sanchez
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Andrea X Moore
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Marc Hernaiz-Llorens
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Carmine L Chavez-Martinez
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA; Graduate program in Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Chimuanya K Agba
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA; Neurosciences Graduate Program, University of California San Diego, La Jolla, CA, USA USA
| | - Haoyue Li
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Joseph Zhang
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Daniel T Lusk
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Kayla M Cervantes
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Binhai Zheng
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA; VA San Diego Research Service, San Diego, CA, USA.
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Metcalfe M, Steward O. PTEN deletion in spinal pathways via retrograde transduction with AAV-RG enhances forelimb motor recovery after cervical spinal cord injury; Sex differences and late-onset pathophysiologies. Exp Neurol 2023; 370:114551. [PMID: 37778650 DOI: 10.1016/j.expneurol.2023.114551] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/08/2023] [Accepted: 09/25/2023] [Indexed: 10/03/2023]
Abstract
Spinal cord injuries (SCI) cause permanent functional impairments due to interruption of motor and sensory pathways. Regeneration of axons does not occur due to lack of intrinsic growth capacity of adult neurons and extrinsic inhibitory factors, especially at the injury site. However, some regeneration can be achieved via deletion of the phosphatase and tensin homolog (PTEN) in cells of origin of spinal pathways. Here, we deployed an AAV variant that is retrogradely transported (AAV-rg) to deliver gene modifying cargos to the cells of origin of multiple pathways interrupted by SCI, testing whether this promoted recovery of motor function. PTENf/f;RosatdTomato mice and control RosatdTomato mice received injections of different doses (number of genome copies, GCs) of AAV-rg/Cre into the cervical spinal cord at the time of a C5 dorsal hemisection injury. Forelimb grip strength was tested over time using a grip strength meter. PTENf/f;RosatdTomato mice with AAV-rg/Cre (PTEN-deleted) exhibited substantial improvements in forelimb gripping ability in comparison to controls. Of note, there were major sex differences in the extent of recovery, with male mice exhibiting greater recovery than females. However, at around 5-7 weeks post-injury/injection, many mice with SCI and AAV-rg-mediated PTEN deletion began to exhibit pathophysiologies involving excessive scratching of the ears and back of the neck and rigid forward extension of the hindlimbs. These pathophysiologies increased in incidence and severity over time. Our results reveal that although intra-spinal injections of AAV-rg/Cre in PTENf/f;RosatdTomato mice can enhance forelimb motor recovery after SCI, late-developing functional abnormalities occur with the experimental conditions used here. Mechanisms underlying late-developing pathophysiologies remain to be defined.
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Affiliation(s)
- Mariajose Metcalfe
- Reeve-Irvine Research Center University of California Irvine School of Medicine, USA; Department of Anatomy & Neurobiology, University of California Irvine School of Medicine, USA
| | - Oswald Steward
- Reeve-Irvine Research Center University of California Irvine School of Medicine, USA; Department of Anatomy & Neurobiology, University of California Irvine School of Medicine, USA; Department of Neurobiology & Behavior, University of California Irvine, USA; Department of Neurosurgery, University of California Irvine School of Medicine, USA.
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7
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Leibinger M, Zeitler C, Paulat M, Gobrecht P, Hilla A, Andreadaki A, Guthoff R, Fischer D. Inhibition of microtubule detyrosination by parthenolide facilitates functional CNS axon regeneration. eLife 2023; 12:RP88279. [PMID: 37846146 PMCID: PMC10581688 DOI: 10.7554/elife.88279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2023] Open
Abstract
Injured axons in the central nervous system (CNS) usually fail to regenerate, causing permanent disabilities. However, the knockdown of Pten knockout or treatment of neurons with hyper-IL-6 (hIL-6) transforms neurons into a regenerative state, allowing them to regenerate axons in the injured optic nerve and spinal cord. Transneuronal delivery of hIL-6 to the injured brain stem neurons enables functional recovery after severe spinal cord injury. Here we demonstrate that the beneficial hIL-6 and Pten knockout effects on axon growth are limited by the induction of tubulin detyrosination in axonal growth cones. Hence, cotreatment with parthenolide, a compound blocking microtubule detyrosination, synergistically accelerates neurite growth of cultured murine CNS neurons and primary RGCs isolated from adult human eyes. Systemic application of the prodrug dimethylamino-parthenolide (DMAPT) facilitates axon regeneration in the injured optic nerve and spinal cord. Moreover, combinatorial treatment further improves hIL-6-induced axon regeneration and locomotor recovery after severe SCI. Thus, DMAPT facilitates functional CNS regeneration and reduces the limiting effects of pro-regenerative treatments, making it a promising drug candidate for treating CNS injuries.
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Affiliation(s)
- Marco Leibinger
- Center for Pharmacology, Institute II, Medical Faculty and University of CologneCologneGermany
- Department of Cell Physiology, Ruhr University of BochumBochumGermany
| | - Charlotte Zeitler
- Center for Pharmacology, Institute II, Medical Faculty and University of CologneCologneGermany
- Department of Cell Physiology, Ruhr University of BochumBochumGermany
| | - Miriam Paulat
- Department of Cell Physiology, Ruhr University of BochumBochumGermany
| | - Philipp Gobrecht
- Center for Pharmacology, Institute II, Medical Faculty and University of CologneCologneGermany
- Department of Cell Physiology, Ruhr University of BochumBochumGermany
| | - Alexander Hilla
- Department of Cell Physiology, Ruhr University of BochumBochumGermany
| | - Anastasia Andreadaki
- Center for Pharmacology, Institute II, Medical Faculty and University of CologneCologneGermany
- Department of Cell Physiology, Ruhr University of BochumBochumGermany
| | - Rainer Guthoff
- Eye Hospital, Heinrich Heine University DüsseldorfDüsseldorfGermany
| | - Dietmar Fischer
- Center for Pharmacology, Institute II, Medical Faculty and University of CologneCologneGermany
- Department of Cell Physiology, Ruhr University of BochumBochumGermany
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8
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Stewart AN, Kumari R, Bailey WM, Glaser EP, Bosse-Joseph CC, Park KA, Hammers GV, Wireman OH, Gensel JC. PTEN knockout using retrogradely transported AAVs transiently restores locomotor abilities in both acute and chronic spinal cord injury. Exp Neurol 2023; 368:114502. [PMID: 37558155 PMCID: PMC10498341 DOI: 10.1016/j.expneurol.2023.114502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 07/07/2023] [Accepted: 08/07/2023] [Indexed: 08/11/2023]
Abstract
Restoring function in chronic stages of spinal cord injury (SCI) has often been met with failure or reduced efficacy when regenerative strategies are delayed past the acute or sub-acute stages of injury. Restoring function in the chronically injured spinal cord remains a critical challenge. We found that a single injection of retrogradely transported adeno-associated viruses (AAVrg) to knockout the phosphatase and tensin homolog protein (PTEN) in chronic SCI can effectively target both damaged and spared axons and transiently restore locomotor functions in near-complete injury models. AAVrg's were injected to deliver cre recombinase and/or a red fluorescent protein (RFP) under the human Synapsin 1 promoter (hSyn1) into the spinal cords of C57BL/6 PTENFloxΔ/Δ mice to knockout PTEN (PTEN-KO) in a severe thoracic SCI crush model at both acute and chronic time points. PTEN-KO improved locomotor abilities in both acute and chronic SCI conditions over a 9-week period. Regardless of whether treatment was initiated at the time of injury (acute), or three months after SCI (chronic), mice with limited hindlimb joint movement gained hindlimb weight support after treatment. Interestingly, functional improvements were not sustained beyond 9 weeks coincident with a loss of RFP reporter-gene expression and a near-complete loss of treatment-associated functional recovery by 6 months post-treatment. Treatment effects were also specific to severely injured mice; animals with weight support at the time of treatment lost function over a 6-month period. Retrograde tracing with Fluorogold revealed viable neurons throughout the motor cortex despite a loss of RFP expression at 9 weeks post-PTEN-KO. However, few Fluorogold labeled neurons were detected within the motor cortex at 6 months post-treatment. BDA labeling from the motor cortex revealed a dense corticospinal tract (CST) bundle in all groups except chronically treated PTEN-KO mice, indicating a potential long-term toxic effect of PTEN-KO to neurons in the motor cortex which was corroborated by a loss of β-tubulin III labeling above the lesion within spinal cords after PTEN-KO. PTEN-KO mice had significantly more β-tubulin III labeled axons within the lesion when treatment was delivered acutely, but not chronically post-SCI. In conclusion, we have found that using AAVrg's to knockout PTEN is an effective manipulation capable of restoring motor functions in chronic SCI and can enhance axon growth of currently unidentified axon populations when delivered acutely after injury. However, the long-term consequences of PTEN-KO on neuronal health and viability should be further explored.
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Affiliation(s)
- Andrew N Stewart
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA.
| | - Reena Kumari
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA
| | - William M Bailey
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA
| | - Ethan P Glaser
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA
| | - Christopher C Bosse-Joseph
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA
| | - Kennedy A Park
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA
| | - Gabrielle V Hammers
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA
| | - Olivia H Wireman
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA
| | - John C Gensel
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA; College of Medicine, University of Kentucky, Lexington, KY 40536, USA.
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9
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Metcalfe M, Steward O. PTEN deletion in spinal pathways via retrograde transduction with AAV-rg enhances forelimb motor recovery after cervical spinal cord injury; sex differences and late-onset pathophysiologies. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.20.533502. [PMID: 36993317 PMCID: PMC10055283 DOI: 10.1101/2023.03.20.533502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Spinal cord injuries (SCI) cause permanent functional impairments due to interruption of motor and sensory pathways. Regeneration of axons does not occur due to lack of intrinsic growth capacity of adult neurons and extrinsic inhibitory factors, especially at the injury site. However, some regeneration can be achieved via deletion of the phosphatase and tensin homolog (PTEN) in cells of origin of spinal pathways. Here, we deployed an AAV variant that is retrogradely transported (AAV-rg) to deliver gene modifying cargos to the cells of origin of multiple pathways interrupted by SCI, testing whether this promoted recovery of motor function. PTEN f/f ;Rosa tdTomato mice and control Rosa tdTomato mice received injections of different doses (number of genome copies, GCs) of AAV-rg/Cre into the cervical spinal cord at the time of a C5 dorsal hemisection injury. Forelimb grip strength was tested over time using a grip strength meter. PTEN f/f ;Rosa tdTomato mice with AAV-rg/Cre (PTEN-deleted) exhibited substantial improvements in forelimb gripping ability in comparison to controls. Of note, there were major sex differences in the extent of recovery, with male mice exhibiting greater recovery than females. However, at around 5-7 weeks post-injury/injection, many mice with SCI and AAV-rg-mediated PTEN deletion began to exhibit pathophysiologies involving excessive scratching of the ears and back of the neck and rigid forward extension of the hindlimbs. These pathophysiologies increased in incidence and severity over time. Our results reveal that although intra-spinal injections of AAV-rg/Cre in PTEN f/f ;Rosa tdTomato mice can enhance forelimb motor recovery after SCI, late-developing functional abnormalities occur with the experimental conditions used here. Mechanisms underlying late-developing pathophysiologies remain to be defined.
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10
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Lear BP, Moore DL. Moving CNS axon growth and regeneration research into human model systems. Front Neurosci 2023; 17:1198041. [PMID: 37425013 PMCID: PMC10324669 DOI: 10.3389/fnins.2023.1198041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 05/25/2023] [Indexed: 07/11/2023] Open
Abstract
Axon regeneration is limited in the adult mammalian central nervous system (CNS) due to both intrinsic and extrinsic factors. Rodent studies have shown that developmental age can drive differences in intrinsic axon growth ability, such that embryonic rodent CNS neurons extend long axons while postnatal and adult CNS neurons do not. In recent decades, scientists have identified several intrinsic developmental regulators in rodents that modulate growth. However, whether this developmentally programmed decline in CNS axon growth is conserved in humans is not yet known. Until recently, there have been limited human neuronal model systems, and even fewer age-specific human models. Human in vitro models range from pluripotent stem cell-derived neurons to directly reprogrammed (transdifferentiated) neurons derived from human somatic cells. In this review, we discuss the advantages and disadvantages of each system, and how studying axon growth in human neurons can provide species-specific knowledge in the field of CNS axon regeneration with the goal of bridging basic science studies to clinical trials. Additionally, with the increased availability and quality of 'omics datasets of human cortical tissue across development and lifespan, scientists can mine these datasets for developmentally regulated pathways and genes. As there has been little research performed in human neurons to study modulators of axon growth, here we provide a summary of approaches to begin to shift the field of CNS axon growth and regeneration into human model systems to uncover novel drivers of axon growth.
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Affiliation(s)
| | - Darcie L. Moore
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, United States
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11
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Stewart AN, Kumari R, Bailey WM, Glaser EP, Hammers GV, Wireman OH, Gensel JC. PTEN knockout using retrogradely transported AAVs restores locomotor abilities in both acute and chronic spinal cord injury. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.17.537179. [PMID: 37131840 PMCID: PMC10153160 DOI: 10.1101/2023.04.17.537179] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Restoring function in chronic stages of spinal cord injury (SCI) has often been met with failure or reduced efficacy when regenerative strategies are delayed past the acute or sub-acute stages of injury. Restoring function in the chronically injured spinal cord remains a critical challenge. We found that a single injection of retrogradely transported adeno-associated viruses (AAVrg) to knockout the phosphatase and tensin homolog protein (PTEN) in chronic SCI can effectively target both damaged and spared axons and restore locomotor functions in near-complete injury models. AAVrg's were injected to deliver cre recombinase and/or a red fluorescent protein (RFP) under the human Synapsin 1 promoter (hSyn1) into the spinal cords of C57BL/6 PTEN FloxΔ / Δ mice to knockout PTEN (PTEN-KO) in a severe thoracic SCI crush model at both acute and chronic time points. PTEN-KO improved locomotor abilities in both acute and chronic SCI conditions over a 9-week period. Regardless of whether treatment was initiated at the time of injury (acute), or three months after SCI (chronic), mice with limited hindlimb joint movement gained hindlimb weight support after treatment. Interestingly, functional improvements were not sustained beyond 9 weeks coincident with a loss of RFP reporter-gene expression and a near-complete loss of treatment-associated functional recovery by 6 months post-treatment. Treatment effects were also specific to severely injured mice; animals with weight support at the time of treatment lost function over a 6-month period. Retrograde tracing with Fluorogold revealed viable neurons throughout the motor cortex despite a loss of RFP expression at 9 weeks post-PTEN-KO. However, few Fluorogold labeled neurons were detected within the motor cortex at 6 months post-treatment. BDA labeling from the motor cortex revealed a dense corticospinal tract (CST) bundle in all groups except chronically treated PTEN-KO mice indicating a potential long-term toxic effect of PTEN-KO to neurons in the motor cortex. PTEN-KO mice had significantly more β - tubulin III labeled axons within the lesion when treatment was delivered acutely, but not chronically post-SCI. In conclusion, we have found that using AAVrg's to knockout PTEN is an effective manipulation capable of restoring motor functions in chronic SCI and can enhance axon growth of currently unidentified axon populations when delivered acutely after injury. However, the long-term consequences of PTEN-KO may exert neurotoxic effects.
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Affiliation(s)
- Andrew N. Stewart
- Department of Physiology, University of Kentucky, Lexington, Kentucky 40536, USA
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky 40536, USA
| | - Reena Kumari
- Department of Physiology, University of Kentucky, Lexington, Kentucky 40536, USA
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky 40536, USA
| | - William M. Bailey
- Department of Physiology, University of Kentucky, Lexington, Kentucky 40536, USA
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky 40536, USA
| | - Ethan P. Glaser
- Department of Physiology, University of Kentucky, Lexington, Kentucky 40536, USA
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky 40536, USA
| | - Gabrielle V. Hammers
- Department of Physiology, University of Kentucky, Lexington, Kentucky 40536, USA
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky 40536, USA
| | - Olivia H. Wireman
- Department of Physiology, University of Kentucky, Lexington, Kentucky 40536, USA
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky 40536, USA
| | - John C. Gensel
- Department of Physiology, University of Kentucky, Lexington, Kentucky 40536, USA
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky 40536, USA
- College of Medicine, University of Kentucky, Lexington, Kentucky 40536, USA
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Kim HN, McCrea MR, Li S. Advances in molecular therapies for targeting pathophysiology in spinal cord injury. Expert Opin Ther Targets 2023; 27:171-187. [PMID: 37017093 PMCID: PMC10148912 DOI: 10.1080/14728222.2023.2194532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 03/20/2023] [Accepted: 03/20/2023] [Indexed: 04/06/2023]
Abstract
INTRODUCTION Spinal cord injury (SCI) affects 25,000-50,000 people around the world each year and there is no cure for SCI patients currently. The primary injury damages spinal cord tissues and secondary injury mechanisms, including ischemia, apoptosis, inflammation, and astrogliosis, further exacerbate the lesions to the spinal cord. Recently, researchers have designed various therapeutic approaches for SCI by targeting its major cellular or molecular pathophysiology. AREAS COVERED Some strategies have shown promise in repairing injured spinal cord for functional recoveries, such as administering neuroprotective reagents, targeting specific genes to promote robust axon regeneration of disconnected spinal fiber tracts, targeting epigenetic factors to enhance cell survival and neural repair, and facilitating neuronal relay pathways and neuroplasticity for restoration of function after SCI. This review focuses on the major advances in preclinical molecular therapies for SCI reported in recent years. EXPERT OPINION Recent progress in developing novel and effective repairing strategies for SCI is encouraging, but many challenges remain for future design of effective treatments, including developing highly effective neuroprotectants for early interventions, stimulating robust neuronal regeneration with functional synaptic reconnections among disconnected neurons, maximizing the recovery of lost neural functions with combination strategies, and translating the most promising therapies into human use.
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Affiliation(s)
- Ha Neui Kim
- Shriners Hospitals Pediatric Research Center, Department of Neural Sciences, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Madeline R. McCrea
- Shriners Hospitals Pediatric Research Center, Department of Neural Sciences, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Shuxin Li
- Shriners Hospitals Pediatric Research Center, Department of Neural Sciences, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
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Kim H, Saikia J, Monte K, Ha E, Romaus-Sanjurjo D, Sanchez J, Moore A, Hernaiz-Llorens M, Chavez-Martinez C, Agba C, Li H, Lusk D, Cervantes K, Zheng B. Probing regenerative heterogeneity of corticospinal neurons with scRNA-Seq. RESEARCH SQUARE 2023:rs.3.rs-2588274. [PMID: 36865182 PMCID: PMC9980198 DOI: 10.21203/rs.3.rs-2588274/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The corticospinal tract (CST) is clinically important for the recovery of motor functions after spinal cord injury. Despite substantial progress in understanding the biology of axon regeneration in the central nervous system (CNS), our ability to promote CST regeneration remains limited. Even with molecular interventions, only a small proportion of CST axons regenerate1. Here we investigate this heterogeneity in the regenerative ability of corticospinal neurons following PTEN and SOCS3 deletion with patch-based single cell RNA sequencing (scRNA-Seq)2,3, which enables deep sequencing of rare regenerating neurons. Bioinformatic analyses highlighted the importance of antioxidant response and mitochondrial biogenesis along with protein translation. Conditional gene deletion validated a role for NFE2L2 (or NRF2), a master regulator of antioxidant response, in CST regeneration. Applying Garnett4, a supervised classification method, to our dataset gave rise to a Regenerating Classifier (RC), which, when applied to published scRNA-Seq data, generates cell type- and developmental stage-appropriate classifications. While embryonic brain, adult dorsal root ganglion and serotonergic neurons are classified as Regenerators, most neurons from adult brain and spinal cord are classified as Non-regenerators. Adult CNS neurons partially revert to a regenerative state soon after injury, which is accelerated by molecular interventions. Our data indicate the existence of universal transcriptomic signatures underlying the regenerative abilities of vastly different neuronal populations, and further illustrate that deep sequencing of only hundreds of phenotypically identified CST neurons has the power to reveal new insights into their regenerative biology.
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Affiliation(s)
- Hugo Kim
- University of California San Diego
| | | | | | - Eunmi Ha
- University of California San Diego
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14
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Zheng B, Tuszynski MH. Regulation of axonal regeneration after mammalian spinal cord injury. Nat Rev Mol Cell Biol 2023; 24:396-413. [PMID: 36604586 DOI: 10.1038/s41580-022-00562-y] [Citation(s) in RCA: 57] [Impact Index Per Article: 57.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2022] [Indexed: 01/06/2023]
Abstract
One hundred years ago, Ramón y Cajal, considered by many as the founder of modern neuroscience, stated that neurons of the adult central nervous system (CNS) are incapable of regenerating. Yet, recent years have seen a tremendous expansion of knowledge in the molecular control of axon regeneration after CNS injury. We now understand that regeneration in the adult CNS is limited by (1) a failure to form cellular or molecular substrates for axon attachment and elongation through the lesion site; (2) environmental factors, including inhibitors of axon growth associated with myelin and the extracellular matrix; (3) astrocyte responses, which can both limit and support axon growth; and (4) intraneuronal mechanisms controlling the establishment of an active cellular growth programme. We discuss these topics together with newly emerging hypotheses, including the surprising finding from transcriptomic analyses of the corticospinal system in mice that neurons revert to an embryonic state after spinal cord injury, which can be sustained to promote regeneration with neural stem cell transplantation. These gains in knowledge are steadily advancing efforts to develop effective treatment strategies for spinal cord injury in humans.
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Affiliation(s)
- Binhai Zheng
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA. .,VA San Diego Research Service, San Diego, CA, USA.
| | - Mark H Tuszynski
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA. .,VA San Diego Research Service, San Diego, CA, USA.
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15
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Reshamwala R, Shah M. Regenerative Approaches in the Nervous System. Regen Med 2023. [DOI: 10.1007/978-981-19-6008-6_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
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16
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Noristani HN. Intrinsic regulation of axon regeneration after spinal cord injury: Recent advances and remaining challenges. Exp Neurol 2022; 357:114198. [DOI: 10.1016/j.expneurol.2022.114198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 07/20/2022] [Accepted: 08/02/2022] [Indexed: 11/16/2022]
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17
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Xia M, Zhang Q, Zhang Y, Li R, Zhao T, Chen L, Liu Q, Zheng S, Li H, Qian Z, Yang L. Growth Differentiation Factor 15 Regulates Oxidative Stress-Dependent Ferroptosis Post Spinal Cord Injury by Stabilizing the p62-Keap1-Nrf2 Signaling Pathway. Front Aging Neurosci 2022; 14:905115. [PMID: 35860670 PMCID: PMC9289442 DOI: 10.3389/fnagi.2022.905115] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 05/31/2022] [Indexed: 01/12/2023] Open
Abstract
Background Spinal cord injury (SCI) is a severe traumatic disorder of the central nervous system (CNS) that causes irreversible damage to the nervous tissue. The consequent hemorrhage contributed by trauma induces neuronal ferroptosis post SCI, which is an important death mode to mediate neuronal loss. Growth differentiation factor 15 (GDF15) is a cytokine that regulates cell proliferation, differentiation, and death. However, the specific role of GDF15 in neuronal ferroptosis post SCI remains unknown. Materials and Methods Neuronal ferroptosis in vitro was measured by detection of lipid peroxidation, glutathione, iron content, and reactive oxidative stress. In vivo, western blotting and immunofluorescence (IF) staining was utilized to measure ferroptosis post SCI. IF staining, TUNEL staining, hematoxylin-eosin staining, and Nissl staining were used to measure neurological damage. Finally, locomotor function recovery was analyzed using the Basso Mouse Scale and Louisville Swim Scale. Results GDF15 was significantly increased in neuronal ferroptosis and silencing GDF15 aggravated ferroptosis both in vitro and in vivo. Besides, GDF15-mediated inhibition of neuronal ferroptosis is through p62-dependent Keap1-Nrf2 pathway. In SCI mice, knockdown of GDF15 significantly exacerbated neuronal death, interfered with axon regeneration and remyelination, aggravated ferroptosis-mediated neuroinflammation, and restrained locomotor recovery. Conclusion GDF15 effectively alleviated neuronal ferroptosis post SCI via the p62-Keap1-Nrf2 signaling pathway and promoted locomotor recovery of SCI mice, which is suggested as a potential target on SCI pathogenesis and treatment.
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Affiliation(s)
- Mingjie Xia
- Department of Orthopedics, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Qinyang Zhang
- Postgraduate School, Dalian Medical University, Dalian, China
- Department of Orthopedics, Taizhou People’s Hospital, Nanjing Medical University, Taizhou, China
| | - Yanan Zhang
- Postgraduate School, Dalian Medical University, Dalian, China
- Department of Orthopedics, Taizhou People’s Hospital, Nanjing Medical University, Taizhou, China
| | - Rulin Li
- Postgraduate School, Dalian Medical University, Dalian, China
- Department of Orthopedics, Taizhou People’s Hospital, Nanjing Medical University, Taizhou, China
| | - Tianyu Zhao
- Postgraduate School, Dalian Medical University, Dalian, China
- Department of Orthopedics, Taizhou People’s Hospital, Nanjing Medical University, Taizhou, China
| | - Lingxia Chen
- Department of Cardiology, Nanjing University of Chinese Medicine, Nanjing, China
| | - Qiangxian Liu
- Department of Orthopedics, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Shengnai Zheng
- Department of Orthopedics, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Haijun Li
- Department of Orthopedics, Taizhou People’s Hospital, Nanjing Medical University, Taizhou, China
- Taizhou Clinical Medical School of Nanjing Medical University, Taizhou, China
- *Correspondence: Haijun Li,
| | - Zhanyang Qian
- Department of Orthopedics, Zhongda Hospital of Southeast University, Nanjing, China
- School of Medicine, Southeast University, Nanjing, China
- Zhanyang Qian,
| | - Lei Yang
- Department of Orthopedics, Taizhou People’s Hospital, Nanjing Medical University, Taizhou, China
- Taizhou Clinical Medical School of Nanjing Medical University, Taizhou, China
- School of Biomedical Engineering and Informatics, Nanjing Medical University, Nanjing, China
- Lei Yang,
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18
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Self-delivering RNAi compounds as therapeutic agents in the central nervous system to enhance axonal regeneration after injury. iScience 2022; 25:104379. [PMID: 35620420 PMCID: PMC9127586 DOI: 10.1016/j.isci.2022.104379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 12/10/2021] [Accepted: 05/04/2022] [Indexed: 12/01/2022] Open
Abstract
The therapeutic use of RNAi has grown but often faces several hurdles related to delivery systems, compound stability, immune activation, and on-target/off-tissue effects. Self-delivering RNAi (sdRNA) molecules do not require delivery agents or excipients. Here we demonstrate the ability of sdRNA to reduce the expression of PTEN (phosphatase and tensin homolog) to stimulate regenerative axon regrowth in the injured adult CNS. PTEN-targeting sdRNA compounds were tested for efficacy in vivo by intravitreal injection after adult rat optic nerve injury. We describe critical steps in lead compound generation through the optimization of nucleotide modifications, enhancements for stability in biological matrices, and screening for off-target immunostimulatory activity. The data show that PTEN expression in vivo can be reduced using sdRNA and this enhances regeneration in adult CNS neurons after injury, raising the possibility that this method could be utilized for other clinically relevant nervous system indications. self-delivering siRNA (sdRNA) can decrease neuronal gene expression in vivo sdRNA can be successfully delivered in vivo without using vectors or excipients Phosphatase and tensin homolog (PTEN)-targeting sdRNA can enhance CNS neuronal regeneration after injury
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19
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Hausott B, Glueckert R, Schrott-Fischer A, Klimaschewski L. Signal Transduction Regulators in Axonal Regeneration. Cells 2022; 11:cells11091537. [PMID: 35563843 PMCID: PMC9104247 DOI: 10.3390/cells11091537] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/27/2022] [Accepted: 04/28/2022] [Indexed: 11/16/2022] Open
Abstract
Intracellular signal transduction in response to growth factor receptor activation is a fundamental process during the regeneration of the nervous system. In this context, intracellular inhibitors of neuronal growth factor signaling have become of great interest in the recent years. Among them are the prominent signal transduction regulators Sprouty (SPRY) and phosphatase and tensin homolog deleted on chromosome 10 (PTEN), which interfere with major signaling pathways such as extracellular signal-regulated kinase (ERK) or phosphoinositide 3-kinase (PI3K)/Akt in neurons and glial cells. Furthermore, SPRY and PTEN are themselves tightly regulated by ubiquitin ligases such as c-casitas b-lineage lymphoma (c-CBL) or neural precursor cell expressed developmentally down-regulated protein 4 (NEDD4) and by different microRNAs (miRs) including miR-21 and miR-222. SPRY, PTEN and their intracellular regulators play an important role in the developing and the lesioned adult central and peripheral nervous system. This review will focus on the effects of SPRY and PTEN as well as their regulators in various experimental models of axonal regeneration in vitro and in vivo. Targeting these signal transduction regulators in the nervous system holds great promise for the treatment of neurological injuries in the future.
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Affiliation(s)
- Barbara Hausott
- Institute of Neuroanatomy, Medical University Innsbruck, 6020 Innsbruck, Austria;
- Correspondence:
| | - Rudolf Glueckert
- Department of Otorhinolaryngology, Medical University Innsbruck, 6020 Innsbruck, Austria; (R.G.); (A.S.-F.)
| | - Anneliese Schrott-Fischer
- Department of Otorhinolaryngology, Medical University Innsbruck, 6020 Innsbruck, Austria; (R.G.); (A.S.-F.)
| | - Lars Klimaschewski
- Institute of Neuroanatomy, Medical University Innsbruck, 6020 Innsbruck, Austria;
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20
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Islam A, Tom VJ. The use of viral vectors to promote repair after spinal cord injury. Exp Neurol 2022; 354:114102. [PMID: 35513025 DOI: 10.1016/j.expneurol.2022.114102] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 04/21/2022] [Accepted: 04/27/2022] [Indexed: 11/16/2022]
Abstract
Spinal cord injury (SCI) is a devastating event that can permanently disrupt multiple modalities. Unfortunately, the combination of the inhibitory environment at a central nervous system (CNS) injury site and the diminished intrinsic capacity of adult axons for growth results in the failure for robust axonal regeneration, limiting the ability for repair. Delivering genetic material that can either positively or negatively modulate gene expression has the potential to counter the obstacles that hinder axon growth within the spinal cord after injury. A popular gene therapy method is to deliver the genetic material using viral vectors. There are considerations when deciding on a viral vector approach for a particular application, including the type of vector, as well as serotypes, and promoters. In this review, we will discuss some of the aspects to consider when utilizing a viral vector approach to as a therapy for SCI. Additionally, we will discuss some recent applications of gene therapy to target extrinsic and/or intrinsic barriers to promote axon regeneration after SCI in preclinical models. While still in early stages, this approach has potential to treat those living with SCI.
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Affiliation(s)
- Ashraful Islam
- Drexel University College of Medicine, Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Philadelphia, PA, USA
| | - Veronica J Tom
- Drexel University College of Medicine, Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Philadelphia, PA, USA.
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21
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Schrank S, Satkunendrarajah K. Viral tools for mapping and modulating neural networks after spinal cord injury. Exp Neurol 2022; 351:113995. [DOI: 10.1016/j.expneurol.2022.113995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 01/26/2022] [Indexed: 11/04/2022]
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22
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Harnessing rAAV-retro for gene manipulations in multiple pathways that are interrupted after spinal cord injury. Exp Neurol 2021; 350:113965. [PMID: 34973965 DOI: 10.1016/j.expneurol.2021.113965] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 12/17/2021] [Accepted: 12/23/2021] [Indexed: 12/12/2022]
Abstract
This paper explores the potential of rAAV2-retro to deliver gene modifying cargoes to the cells of origin of multiple pathways that are interrupted by spinal cord injury (SCI), summarizing data from previous studies and new data from additional experiments. rAAV-retro exhibits uniquely robust and reliable long-distance retrograde transport from pre-terminal axons and synapses back to neuronal bodies. Previous studies have documented that various AAV-based genetic modifications can enable axon regeneration after SCI, but these have targeted the cells of origin of one pathway at a time. In contrast, rAAV-retro can simultaneously transduce large numbers of neurons of origin of multiple spinal pathways with single injections into the spinal cord. Our initial studies use RosatdTomato and double transgenic PTENf/f; RosatdTomato mice in which transfection with rAAV-retro/Cre deletes PTEN and activates tdT expression in the same neurons. Injections of rAAV-retro/Cre into the cervical, thoracic and lumbar spinal cord led to topographically specific retrograde transduction in cortical motoneurons and neurons in subcortical regions that give rise to different spinal pathways. Our results confirm and extend previous studies indicating selective transduction of neurons that terminate at the level of the injection with minimal retrograde transduction of axons in transit to lower levels. We document feasibility of using rAAV-retro expressing shRNA against PTEN along with a GFP reporter (rAAV-retro-shPTEN/GFP) to effectively knock down PTEN in multiple populations of neurons, which can be used in any species. Some limitations and caveats of currently available rAAV-retros are discussed. Together, our results support the potential applications of rAAV-retro for AAV-based gene-modifications for SCI.
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Steward O, Coulibaly AP, Metcalfe M, Dam JM, Yee KM. AAV vectors accumulate in the pineal gland after injections into the brain or spinal cord. Mol Ther Methods Clin Dev 2021; 23:406-417. [PMID: 34761054 PMCID: PMC8560646 DOI: 10.1016/j.omtm.2021.09.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 09/20/2021] [Accepted: 09/29/2021] [Indexed: 11/25/2022]
Abstract
AAV vectors are being used extensively for gene-modifying therapies for neurological disorders. Here, we report the surprising discovery that injections of different AAVs into the brain, spinal cord, or cerebrospinal fluid (CSF) lead to robust transduction of cells in the pineal gland. We document transduction of cells in the pineal gland following focal injections of AAV2/9-shPTEN-zsGreen into the sensorimotor or hippocampus of rats and injections of AAV2/Cre into the spinal cord of transgenic mice with a stop-flox tdT reporter. Pineal transduction was evident even when AAV2/Cre injections were made into the lumbar spinal cord many millimeters distant from the pineal gland. Immunostaining with antibodies for cell types in the pineal gland revealed that pinealocytes were transduced. Pineal transduction was also observed with intracerebroventricular (i.c.v.) injections of AAV2/9-shPTEN-zsGreen, suggesting that pineal transduction following focal injections of AAV into CNS parenchyma may be caused by diffusion of the vector from the injection sites into the CSF and then accumulation in the pineal gland. Together, these findings suggest the need for vigilance for functional consequences and possible adverse effects of off-target accumulation of therapeutic AAVs in the pineal gland and AAV-driven expression of therapeutic cargos in pinealocytes.
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Affiliation(s)
- Oswald Steward
- Reeve-Irvine Research Center, 837 Health Sciences Drive, University of California Irvine School of Medicine, Irvine, CA 92697, USA
- Department of Anatomy & Neurobiology, University of California Irvine School of Medicine, Irvine, CA 92697, USA
- Department of Neurobiology & Behavior, University of California Irvine School of Medicine, Irvine, CA 92697, USA
- Department of Neurosurgery, University of California Irvine School of Medicine, Irvine, CA 92697, USA
| | - Aminata P. Coulibaly
- Reeve-Irvine Research Center, 837 Health Sciences Drive, University of California Irvine School of Medicine, Irvine, CA 92697, USA
- Department of Anatomy & Neurobiology, University of California Irvine School of Medicine, Irvine, CA 92697, USA
| | - Mariajose Metcalfe
- Reeve-Irvine Research Center, 837 Health Sciences Drive, University of California Irvine School of Medicine, Irvine, CA 92697, USA
| | - Jamie M. Dam
- Reeve-Irvine Research Center, 837 Health Sciences Drive, University of California Irvine School of Medicine, Irvine, CA 92697, USA
| | - Kelly M. Yee
- Reeve-Irvine Research Center, 837 Health Sciences Drive, University of California Irvine School of Medicine, Irvine, CA 92697, USA
- Department of Anatomy & Neurobiology, University of California Irvine School of Medicine, Irvine, CA 92697, USA
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Cao Y, Shi Y, Xiao Z, Chen X, Chen B, Yang B, Shu M, Yin Y, Wu S, Yin W, Fu X, Tan J, Zhou Q, Wu Z, Jiang X, Dai J. Contralateral Axon Sprouting but Not Ipsilateral Regeneration Is Responsible for Spontaneous Locomotor Recovery Post Spinal Cord Hemisection. Front Cell Neurosci 2021; 15:730348. [PMID: 34512270 PMCID: PMC8426601 DOI: 10.3389/fncel.2021.730348] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 08/04/2021] [Indexed: 11/13/2022] Open
Abstract
Spinal cord injury (SCI) usually results in permanent functional impairment and is considered a worldwide medical problem. However, both motor and sensory functions can spontaneously recover to varying extents in humans and animals with incomplete SCI. This study observed a significant spontaneous hindlimb locomotor recovery in Sprague-Dawley rats at four weeks after post-right-side spinal cord hemisection at thoracic 8 (T8). To verify whether the above spontaneous recovery derives from the ipsilateral axonal or neuronal regeneration to reconnect the lesion site, we resected either the scar tissue or right side T7 spinal cord at five weeks post-T8 hemisected injury. The results showed that the spontaneously achieved right hindlimb locomotor function had little change after resection. Furthermore, when T7 left hemisection was performed five weeks after the initial injury, the spontaneously achieved right hindlimb locomotor function was dramatically abolished. A similar result could also be observed when T7 transection was performed after the initial hemisection. The results indicated that it might be the contralateral axonal remolding rather than the ipsilateral axonal or neuronal regeneration beyond the lesion site responsible for the spontaneous hindlimb locomotor recovery. The immunostaining analyses and corticospinal tracts (CSTs) tracing results confirmed this hypothesis. We detected no substantial neuronal and CST regeneration throughout the lesion site; however, significantly more CST fibers were observed to sprout from the contralateral side at the lumbar 4 (L4) spinal cord in the hemisection model rats than in intact ones. In conclusion, this study verified that contralateral CST sprouting, but not ipsilateral CST or neuronal regeneration, is primarily responsible for the spontaneous locomotor recovery in hemisection SCI rats.
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Affiliation(s)
- Yudong Cao
- Department of Neurosurgery, Xiangya Hospital, Central South University (CSU), Changsha, China
| | - Ya Shi
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Zhifeng Xiao
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Xi Chen
- Shigatse Branch, Xinqiao Hospital, Army Medical University (Third Military Medical University), Shigatse, China
| | - Bing Chen
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Bin Yang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Muya Shu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Yanyun Yin
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Shuyu Wu
- Department of Neurosurgery, Xiangya Hospital, Central South University (CSU), Changsha, China
| | - Wen Yin
- Department of Neurosurgery, Xiangya Hospital, Central South University (CSU), Changsha, China
| | - Xianyong Fu
- Department of Neurosurgery, Xiangya Hospital, Central South University (CSU), Changsha, China
| | - Jun Tan
- Department of Neurosurgery, Xiangya Hospital, Central South University (CSU), Changsha, China
| | - Quanwei Zhou
- Department of Neurosurgery, Xiangya Hospital, Central South University (CSU), Changsha, China
| | - Zhaoping Wu
- Department of Neurosurgery, Xiangya Hospital, Central South University (CSU), Changsha, China
| | - Xingjun Jiang
- Department of Neurosurgery, Xiangya Hospital, Central South University (CSU), Changsha, China
| | - Jianwu Dai
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
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25
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Sun T, Duan L, Li J, Guo H, Xiong M. Gypenoside XVII protects against spinal cord injury in mice by regulating the microRNA‑21‑mediated PTEN/AKT/mTOR pathway. Int J Mol Med 2021; 48:146. [PMID: 34132355 PMCID: PMC8208621 DOI: 10.3892/ijmm.2021.4979] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 04/01/2021] [Indexed: 12/14/2022] Open
Abstract
Gypenoside XVII (GP‑17), one of the dominant active components of Gynostemma pentaphyllum, has been studied extensively and found to have a variety of pharmacological effects, including neuroprotective properties. However, the neuroprotective effects of GP‑17 against spinal cord injury (SCI), as well as its underlying mechanisms of action remain unknown. The present study aimed to investigate the effects of GP‑17 on motor recovery and histopathological changes following SCI and to elucidate the mechanisms underlying its neuroprotective effects in a mouse model of SCI. Motor recovery was evaluated using the Basso, Beattie and Bresnahan (BBB) locomotor rating scale. Spinal cord edema was detected by the wet/dry weight method. H&E staining was performed to examine the effect of GP‑17 on spinal cord damage. Inflammatory response production was assessed by ELISA. Candidate miRNAs were identified following the integrated analysis of the Gene Expression Omnibus (GEO) dataset GSE67515. Western blot analysis was also performed to detect the expression levels of associated proteins. The results revealed that GP‑17 treatment improved functional recovery, and suppressed neuronal apoptosis and the inflammatory response in the mouse model of SCI. Moreover, it was observed that miR‑21 expression was downregulated following SCI, whereas it was upregulated following the administration of GP‑17. The inhibition of miR‑21 eliminated the protective effects of GP‑17 on SCI‑induced neuronal apoptosis and the inflammatory response. In addition, phosphatase and tensin homologue (PTEN), a key molecule in the activation of the protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway, was identified as a target of miR‑21, and PTEN expression was downregulated by GP‑17 through miR‑21. Furthermore, the PTEN/AKT/mTOR pathway was inactivated by SCI, whereas it was re‑activated by GP‑17 through the regulation of miR‑21 in mice with SCI. On the whole, the findings of the present study suggest that GP‑17 plays a protective role in SCI via regulating the miR‑21/PTEN/AKT/mTOR pathway.
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Affiliation(s)
- Tianyu Sun
- Department of Traumatology, The First Affiliated Hospital, and College of Clinical Medicine of Henan University of Science and Technology, Luoyang, Henan 471003, P.R. China
| | - Liying Duan
- Department of Basic Medicine, Puyang Medical College, Puyang, Henan 457000, P.R. China
| | - Jiaju Li
- Department of Traumatology, The First Affiliated Hospital, and College of Clinical Medicine of Henan University of Science and Technology, Luoyang, Henan 471003, P.R. China
| | - Hongyu Guo
- Department of Traumatology, The First Affiliated Hospital, and College of Clinical Medicine of Henan University of Science and Technology, Luoyang, Henan 471003, P.R. China
| | - Mingyue Xiong
- Department of Traumatology, The First Affiliated Hospital, and College of Clinical Medicine of Henan University of Science and Technology, Luoyang, Henan 471003, P.R. China
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26
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Bhowmick S, Abdul-Muneer PM. PTEN Blocking Stimulates Corticospinal and Raphespinal Axonal Regeneration and Promotes Functional Recovery After Spinal Cord Injury. J Neuropathol Exp Neurol 2021; 80:169-181. [PMID: 33367790 DOI: 10.1093/jnen/nlaa147] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The long-term disabilities associated with spinal cord injury (SCI) are primarily due to the absence of robust neuronal regeneration and functional plasticity. The inability of the axon to regenerate after SCI is contributed by several intrinsic factors that trigger a cascade of molecular growth program and modulates axonal sprouting. Phosphatase and tensin homolog (PTEN) is one of the intrinsic factors contributing to growth failure after SCI, however, the underlying mechanism is not well known. Here, we developed a novel therapeutic approach for treating SCI by suppressing the action of PTEN in a mouse model of hemisection SCI. We have used a novel peptide, PTEN antagonistic peptide (PAP) to block the critical domains of PTEN to demonstrate its ability to potentially promote axon growth. PAP treatment not only enhanced regeneration of corticospinal axons into the caudal spinal cord but also promoted the regrowth of descending serotonergic axons in SCI mice. Furthermore, expression levels of p-mTOR, p-S6, p-Akt, p-Erk, p-GSK, p-PI3K downstream of PTEN signaling pathway were increased significantly in the spinal cord of SCI mice systemically treated with PAP than control TAT peptide-treated mice. Our novel strategy of administering deliverable compounds postinjury may facilitate translational feasibility for central nervous system injury.
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Affiliation(s)
- Saurav Bhowmick
- From the Laboratory of CNS Injury and Molecular Therapy, JFK Neuroscience Institute, Hackensack Meridian Health JFK University Medical Center, Edison, New Jersey
| | - P M Abdul-Muneer
- Department of Neurology, Hackensack Meridian School of Medicine, Nutley, New Jersey
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27
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Cheng L, Sami A, Ghosh B, Goudsward HJ, Smith GM, Wright MC, Li S, Lepore AC. Respiratory axon regeneration in the chronically injured spinal cord. Neurobiol Dis 2021; 155:105389. [PMID: 33975016 DOI: 10.1016/j.nbd.2021.105389] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 04/19/2021] [Accepted: 05/05/2021] [Indexed: 02/01/2023] Open
Abstract
Promoting the combination of robust regeneration of damaged axons and synaptic reconnection of these growing axon populations with appropriate neuronal targets represents a major therapeutic goal following spinal cord injury (SCI). A key impediment to achieving this important aim includes an intrinsic inability of neurons to extend axons in adult CNS, particularly in the context of the chronically-injured spinal cord. We tested whether an inhibitory peptide directed against phosphatase and tensin homolog (PTEN: a central inhibitor of neuron-intrinsic axon growth potential) could restore inspiratory diaphragm function by reconnecting critical respiratory neural circuitry in a rat model of chronic cervical level 2 (C2) hemisection SCI. We found that systemic delivery of PTEN antagonist peptide 4 (PAP4) starting at 8 weeks after C2 hemisection promoted substantial, long-distance regeneration of injured bulbospinal rostral Ventral Respiratory Group (rVRG) axons into and through the lesion and back toward phrenic motor neurons (PhMNs) located in intact caudal C3-C5 spinal cord. Despite this robust rVRG axon regeneration, PAP4 stimulated only minimal recovery of diaphragm function. Furthermore, re-lesion through the hemisection site completely removed PAP4-induced functional improvement, demonstrating that axon regeneration through the lesion was responsible for this partial functional recovery. Interestingly, there was minimal formation of putative excitatory monosynaptic connections between regrowing rVRG axons and PhMN targets, suggesting that (1) limited rVRG-PhMN synaptic reconnectivity was responsible at least in part for the lack of a significant functional effect, (2) chronically-injured spinal cord presents an obstacle to achieving synaptogenesis between regenerating axons and post-synaptic targets, and (3) addressing this challenge is a potentially-powerful strategy to enhance therapeutic efficacy in the chronic SCI setting. In conclusion, our study demonstrates a non-invasive and transient pharmacological approach in chronic SCI to repair the critically-important neural circuitry controlling diaphragmatic respiratory function, but also sheds light on obstacles to circuit plasticity presented by the chronically-injured spinal cord.
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Affiliation(s)
- Lan Cheng
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Armin Sami
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Biswarup Ghosh
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Hannah J Goudsward
- Department of Biology, Arcadia University, 450 S. Easton Rd., 220 Boyer Hall, Glenside, PA 19038, USA
| | - George M Smith
- Department of Neuroscience, Shriners Hospitals for Pediatric Research Center, Temple University School of Medicine, 3500 North Broad Street, Philadelphia, PA 19140-5104, USA
| | - Megan C Wright
- Department of Biology, Arcadia University, 450 S. Easton Rd., 220 Boyer Hall, Glenside, PA 19038, USA
| | - Shuxin Li
- Department of Neuroscience, Shriners Hospitals for Pediatric Research Center, Temple University School of Medicine, 3500 North Broad Street, Philadelphia, PA 19140-5104, USA
| | - Angelo C Lepore
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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28
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Ehsanipour A, Sathialingam M, Rad LM, de Rutte J, Bierman RD, Liang J, Xiao W, Di Carlo D, Seidlits SK. Injectable, macroporous scaffolds for delivery of therapeutic genes to the injured spinal cord. APL Bioeng 2021; 5:016104. [PMID: 33728392 PMCID: PMC7946441 DOI: 10.1063/5.0035291] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 02/03/2021] [Indexed: 02/06/2023] Open
Abstract
Biomaterials are being developed as therapeutics for spinal cord injury (SCI) that can stabilize and bridge acute lesions and mediate the delivery of transgenes, providing a localized and sustained reservoir of regenerative factors. For clinical use, direct injection of biomaterial scaffolds is preferred to enable conformation to unique lesions and minimize tissue damage. While an interconnected network of cell-sized macropores is necessary for rapid host cell infiltration into-and thus integration of host tissue with-implanted scaffolds, injectable biomaterials have generally suffered from a lack of control over the macrostructure. As genetic vectors have short lifetimes in vivo, rapid host cell infiltration into scaffolds is a prerequisite for efficient biomaterial-mediated delivery of transgenes. We present scaffolds that can be injected and assembled in situ from hyaluronic acid (HA)-based, spherical microparticles to form scaffolds with a network of macropores (∼10 μm). The results demonstrate that addition of regularly sized macropores to traditional hydrogel scaffolds, which have nanopores (∼10 nm), significantly increases the expression of locally delivered transgene to the spinal cord after a thoracic injury. Maximal cell and axon infiltration into scaffolds was observed in scaffolds with more regularly sized macropores. The delivery of lentiviral vectors encoding the brain-derived neurotrophic factor (BDNF), but not neurotrophin-3, from these scaffolds further increased total numbers and myelination of infiltrating axons. Modest improvements to the hindlimb function were observed with BDNF delivery. The results demonstrate the utility of macroporous and injectable HA scaffolds as a platform for localized gene therapies after SCI.
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Affiliation(s)
- Arshia Ehsanipour
- Department of Bioengineering, University of California, Los Angeles, California 90095, USA
| | - Mayilone Sathialingam
- Department of Bioengineering, University of California, Los Angeles, California 90095, USA
| | - Laila M Rad
- Department of Bioengineering, University of California, Los Angeles, California 90095, USA
| | - Joseph de Rutte
- Department of Bioengineering, University of California, Los Angeles, California 90095, USA
| | - Rebecca D Bierman
- Department of Bioengineering, University of California, Los Angeles, California 90095, USA
| | - Jesse Liang
- Department of Bioengineering, University of California, Los Angeles, California 90095, USA
| | - Weikun Xiao
- Department of Bioengineering, University of California, Los Angeles, California 90095, USA
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29
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Pan L, Tan B, Tang W, Luo M, Liu Y, Yu L, Yin Y. Combining task-based rehabilitative training with PTEN inhibition promotes axon regeneration and upper extremity skilled motor function recovery after cervical spinal cord injury in adult mice. Behav Brain Res 2021; 405:113197. [PMID: 33621609 DOI: 10.1016/j.bbr.2021.113197] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 01/30/2021] [Accepted: 02/17/2021] [Indexed: 12/17/2022]
Abstract
BACKGROUND Conditional deletion of Pten in corticospinal neurons promotes axon sprouting and regeneration after spinal cord injury (SCI). However, regeneration studies targeted on PTEN inhibition seldom show motor function recovery. The promotion of functional recovery can be improved by rehabilitative training under a use-dependent plasticity mechanism. PURPOSE To investigate the combined effects of PTEN inhibition and rehabilitative training on axon regeneration and subsequent motor functional improvement after cervical spinal cord injury. METHODS Lentiviral particles (Lenti-PTEN-RNAi or Lenti-Scrambled-EGFP) were injected into the right sensorimotor mouse cortex in four experimental groups (PTEN RNAi + Training, PTEN RNAi, Control + Training, Control). Two weeks after injection, all mouse groups received a left C5 crush injury. We performed task-based rehabilitative training for 4 weeks on the PTEN RNAi + Training and Control + Training groups. Biotinylated dextran amine (BDA) was used for anterograde tracing of the dorsal corticospinal tract (dCST). We analysed axonal regeneration through immunohistochemical methods. A battery of behavioral tests was employed to assess functional recovery at Day3 and every other week after injury. RESULTS Combining rehabilitative training with PTEN inhibition induced more axon regeneration and synapse reformation in the spinal cord caudal to the lesion site. Rostral to the lesion, the transected dCST axons sprouted into gray matter upon contact. Furthermore, forelimb function was found to be improved after combination therapy during behavioral testing. CONCLUSION Combining task-based rehabilitative training with PTEN inhibition further promotes axon regeneration, synaptic plasticity and reorganization of the neural network, with significant improvement in forelimb skilled motor function after cervical spinal cord injury. Our study provides new therapeutic insights for spinal cord injury management in the future.
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Affiliation(s)
- Lu Pan
- Department of Rehabilitation Medicine, the Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Botao Tan
- Department of Rehabilitation Medicine, the Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Weiwei Tang
- Central Laboratory, Xinqiao Hospital, The Army Medical University (Third Military Medical University), Chongqing, 400037, China
| | - Meiling Luo
- Department of Rehabilitation Medicine, the Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Yuan Liu
- State Key Laboratory of Trauma, Burns and Combined Injury, Department of Research Institute of Surgery, Daping Hospital, The Army Medical University, Chongqing, 400042, China
| | - Lehua Yu
- Department of Rehabilitation Medicine, the Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Ying Yin
- Department of Rehabilitation Medicine, the Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China.
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30
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Transneuronal delivery of hyper-interleukin-6 enables functional recovery after severe spinal cord injury in mice. Nat Commun 2021; 12:391. [PMID: 33452250 PMCID: PMC7810685 DOI: 10.1038/s41467-020-20112-4] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Accepted: 11/13/2020] [Indexed: 12/27/2022] Open
Abstract
Spinal cord injury (SCI) often causes severe and permanent disabilities due to the regenerative failure of severed axons. Here we report significant locomotor recovery of both hindlimbs after a complete spinal cord crush. This is achieved by the unilateral transduction of cortical motoneurons with an AAV expressing hyper-IL-6 (hIL-6), a potent designer cytokine stimulating JAK/STAT3 signaling and axon regeneration. We find collaterals of these AAV-transduced motoneurons projecting to serotonergic neurons in both sides of the raphe nuclei. Hence, the transduction of cortical neurons facilitates the axonal transport and release of hIL-6 at innervated neurons in the brain stem. Therefore, this transneuronal delivery of hIL-6 promotes the regeneration of corticospinal and raphespinal fibers after injury, with the latter being essential for hIL-6-induced functional recovery. Thus, transneuronal delivery enables regenerative stimulation of neurons in the deep brain stem that are otherwise challenging to access, yet highly relevant for functional recovery after SCI.
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31
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Moses C, Hodgetts SI, Nugent F, Ben-Ary G, Park KK, Blancafort P, Harvey AR. Transcriptional repression of PTEN in neural cells using CRISPR/dCas9 epigenetic editing. Sci Rep 2020; 10:11393. [PMID: 32647121 PMCID: PMC7347541 DOI: 10.1038/s41598-020-68257-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 06/19/2020] [Indexed: 12/11/2022] Open
Abstract
After damage to the adult mammalian central nervous system (CNS), surviving neurons have limited capacity to regenerate and restore functional connectivity. Conditional genetic deletion of PTEN results in robust CNS axon regrowth, while PTEN repression with short hairpin RNA (shRNA) improves regeneration but to a lesser extent, likely due to suboptimal PTEN mRNA knockdown using this approach. Here we employed the CRISPR/dCas9 system to repress PTEN transcription in neural cells. We targeted the PTEN proximal promoter and 5' untranslated region with dCas9 fused to the repressor protein Krüppel-associated box (KRAB). dCas9-KRAB delivered in a lentiviral vector with one CRISPR guide RNA (gRNA) achieved potent and specific PTEN repression in human cell line models and neural cells derived from human iPSCs, and induced histone (H)3 methylation and deacetylation at the PTEN promoter. The dCas9-KRAB system outperformed a combination of four shRNAs targeting the PTEN transcript, a construct previously used in CNS injury models. The CRISPR system also worked more effectively than shRNAs for Pten repression in rat neural crest-derived PC-12 cells, and enhanced neurite outgrowth after nerve growth factor stimulation. PTEN silencing with CRISPR/dCas9 epigenetic editing may provide a new option for promoting axon regeneration and functional recovery after CNS trauma.
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Affiliation(s)
- C Moses
- School of Human Sciences, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Perth, WA, 6009, Australia
- Cancer Epigenetics Laboratory, The Harry Perkins Institute of Medical Research, 6 Verdun Street, Nedlands, WA, 6009, Australia
| | - S I Hodgetts
- School of Human Sciences, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Perth, WA, 6009, Australia
- Perron Institute for Neurological and Translational Science, 8 Verdun Street, Nedlands, WA, 6009, Australia
| | - F Nugent
- Cancer Epigenetics Laboratory, The Harry Perkins Institute of Medical Research, 6 Verdun Street, Nedlands, WA, 6009, Australia
- School of Molecular Sciences, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Perth, WA, 6009, Australia
| | - G Ben-Ary
- School of Human Sciences, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Perth, WA, 6009, Australia
| | - K K Park
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - P Blancafort
- School of Human Sciences, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Perth, WA, 6009, Australia.
- Cancer Epigenetics Laboratory, The Harry Perkins Institute of Medical Research, 6 Verdun Street, Nedlands, WA, 6009, Australia.
- Greehey Children's Cancer Research Institute, UT Health San Antonio, 8403 Floyd Curl Drive, San Antonio, TX, 78229, USA.
| | - A R Harvey
- School of Human Sciences, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Perth, WA, 6009, Australia.
- Perron Institute for Neurological and Translational Science, 8 Verdun Street, Nedlands, WA, 6009, Australia.
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32
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Fujiki M, Yee KM, Steward O. Non-invasive High Frequency Repetitive Transcranial Magnetic Stimulation (hfrTMS) Robustly Activates Molecular Pathways Implicated in Neuronal Growth and Synaptic Plasticity in Select Populations of Neurons. Front Neurosci 2020; 14:558. [PMID: 32612497 PMCID: PMC7308563 DOI: 10.3389/fnins.2020.00558] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 05/06/2020] [Indexed: 12/21/2022] Open
Abstract
Patterns of neuronal activity that induce synaptic plasticity and memory storage activate kinase cascades in neurons that are thought to be part of the mechanism for synaptic modification. One such cascade involves induction of phosphorylation of ribosomal protein S6 in neurons due to synaptic activation of AKT/mTOR and via a different pathway, activation of MAP kinase/ERK1/2. Here, we show that phosphorylation of ribosomal protein S6 can also be strongly activated by high frequency repetitive transcranial magnetic stimulation (hfrTMS). HfrTMS was delivered to lightly anesthetized rats using a stimulation protocol that is a standard for inducing LTP in the perforant path in vivo (trains of 8 pulses at 400 Hz repeated at intervals of 1/10 s). Stimulation produced stimulus-locked motor responses but did not elicit behavioral seizures either during or after stimulation. After as little as 10 min of hfrTMS, immunostaining using phospho-specific antibodies for the phosphorylated form of ribosomal protein S6 (rpS6) revealed robust induction of rpS6 phosphorylation in large numbers of neurons in the cortex, especially the piriform cortex, and also in thalamic relay nuclei. Quantification revealed that the extent of the increased immunostaining depended on the number of trains and stimulus intensity. Of note, immunostaining for the immediate early genes Arc and c-fos revealed strong induction of IEG expression in many of the same populations of neurons throughout the cortex, but not the thalamus. These results indicate that hfrTMS can robustly activate molecular pathways critical for plasticity, which may contribute to the beneficial effects of TMS on recovery following brain and spinal cord injury and symptom amelioration in human psychiatric disorders. These molecular processes may be a useful surrogate marker to allow optimization of TMS parameters for maximal therapeutic benefit.
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Affiliation(s)
- Minoru Fujiki
- Department of Neurosurgery, School of Medicine, Oita University, Oita, Japan
| | - Kelly Matsudaira Yee
- Reeve-Irvine Research Center, University of California, Irvine, Irvine, CA, United States.,Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA, United States.,Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, United States
| | - Oswald Steward
- Reeve-Irvine Research Center, University of California, Irvine, Irvine, CA, United States.,Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA, United States.,Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, United States
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Gallegos C, Carey M, Zheng Y, He X, Cao QL. Reaching and Grasping Training Improves Functional Recovery After Chronic Cervical Spinal Cord Injury. Front Cell Neurosci 2020; 14:110. [PMID: 32536855 PMCID: PMC7266985 DOI: 10.3389/fncel.2020.00110] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 04/08/2020] [Indexed: 12/31/2022] Open
Abstract
Previous studies suggest locomotion training could be an effective non-invasive therapy after spinal cord injury (SCI) using primarily acute thoracic injuries. However, the majority of SCI patients have chronic cervical injuries. Regaining hand function could significantly increase their quality of life. In this study, we used a clinically relevant chronic cervical contusion to study the therapeutic efficacy of rehabilitation in forelimb functional recovery. Nude rats received a moderate C5 unilateral contusive injury and were then divided into two groups with or without Modified Montoya Staircase (MMS) rehabilitation. For the rehabilitation group, rats were trained 5 days a week starting at 8 weeks post-injury (PI) for 6 weeks. All rats were assessed for skilled forelimb functions with MMS test weekly and for untrained gross forelimb locomotion with grooming and horizontal ladder (HL) tests biweekly. Our results showed that MMS rehabilitation significantly increased the number of pellets taken at 13 and 14 weeks PI and the accuracy rates at 12 to 14 weeks PI. However, there were no significant differences in the grooming scores or the percentage of HL missteps at any time point. Histological analyses revealed that MMS rehabilitation significantly increased the number of serotonergic fibers and the amount of presynaptic terminals around motor neurons in the cervical ventral horns caudal to the injury and reduced glial fibrillary acidic protein (GFAP)-immunoreactive astrogliosis in spinal cords caudal to the lesion. This study shows that MMS rehabilitation can modify the injury environment, promote axonal sprouting and synaptic plasticity, and importantly, improve reaching and grasping functions in the forelimb, supporting the therapeutic potential of task-specific rehabilitation for functional recovery after chronic SCI.
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Affiliation(s)
- Chrystine Gallegos
- The Vivian L. Smith Department of Neurosurgery, The University of Texas Health Science Center at Houston, Houston, TX, United States
- Center for Stem Cell and Regenerative Medicine, The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Matthew Carey
- The Vivian L. Smith Department of Neurosurgery, The University of Texas Health Science Center at Houston, Houston, TX, United States
- Center for Stem Cell and Regenerative Medicine, The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, The University of Texas Health Science Center at Houston, Houston, TX, United States
- Summer Undergraduate Research Program, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Yiyan Zheng
- The Vivian L. Smith Department of Neurosurgery, The University of Texas Health Science Center at Houston, Houston, TX, United States
- Center for Stem Cell and Regenerative Medicine, The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Xiuquan He
- The Vivian L. Smith Department of Neurosurgery, The University of Texas Health Science Center at Houston, Houston, TX, United States
- Center for Stem Cell and Regenerative Medicine, The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, The University of Texas Health Science Center at Houston, Houston, TX, United States
- Department of Anatomy and Histoembryology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Qi Lin Cao
- The Vivian L. Smith Department of Neurosurgery, The University of Texas Health Science Center at Houston, Houston, TX, United States
- Center for Stem Cell and Regenerative Medicine, The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, The University of Texas Health Science Center at Houston, Houston, TX, United States
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Steward O, Coulibaly AP, Metcalfe M, Yonan JM, Yee KM. AAVshRNA-mediated PTEN knockdown in adult neurons attenuates activity-dependent immediate early gene induction. Exp Neurol 2019; 326:113098. [PMID: 31707081 DOI: 10.1016/j.expneurol.2019.113098] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 10/23/2019] [Accepted: 11/05/2019] [Indexed: 12/22/2022]
Abstract
Genetic deletion or knockdown of PTEN enables regeneration of CNS axons, enhances sprouting of intact axons after injury, and induces de novo growth of uninjured adult neurons. It is unknown, however how PTEN deletion in mature neurons alters neuronal physiology. As a first step to address this question, we used immunocytochemistry for activity-dependent markers to assess consequences of PTEN knockdown in cortical neurons and granule cells of the dentate gyrus. In adult rats that received unilateral intra-cortical injections of AAV expressing shRNA against PTEN, immunostaining for c-fos under resting conditions (home cage, HC) and after 1 h of exploration of a novel enriched environment (EE) revealed no hot spots of c-fos expression that would suggest abnormal activity. Counts revealed similar numbers of c-fos positive neurons in the area of PTEN deletion vs. homologous areas in the contralateral cortex in the HC and similar induction of c-fos with EE. However, IEG induction in response to high frequency stimulation (HFS) of the cortex was attenuated in areas of PTEN deletion. In rats with AAVshRNA-mediated PTEN deletion in the dentate gyrus, induction of the IEGs c-fos and Arc with HFS of the perforant path was abrogated in areas of PTEN deletion. Immunostaining using phosphospecific antibodies for phospho-S6 (a downstream marker for mTOR activation) and phospho-ERK1/2 revealed abrogation of S6 phosphorylation in PTEN-deleted areas but preserved activation of phosphorylation of ERK1/2. SIGNIFICANCE STATEMENT: Deletion or knockdown of the tumor suppressor gene PTEN enables regenerative growth of adult CNS axons after injury, which is accompanied by enhanced recovery of function. Consequently, PTEN represents a potential target for therapeutic interventions to enhance recovery after CNS injury. Here we show that activity-dependent IEG induction is attenuated in PTEN-depleted neurons. These findings raise the intriguing possibility that functional recovery due to regenerative growth may be limited by the disruption of plasticity-related signaling pathways, and that recovery might be enhanced by restoring PTEN expression after regenerative growth has been achieved.
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Affiliation(s)
- Oswald Steward
- Reeve-Irvine Research Center, University of California Irvine, USA; Departments of Anatomy & Neurobiology, University of California Irvine, USA; Departments of Neurobiology & Behavior, University of California Irvine, USA; Department of Neurosurgery, University of California Irvine, USA; School of Medicine, University of California Irvine, USA.
| | - Aminata P Coulibaly
- Reeve-Irvine Research Center, University of California Irvine, USA; Departments of Anatomy & Neurobiology, University of California Irvine, USA; School of Medicine, University of California Irvine, USA
| | - Mariajose Metcalfe
- Reeve-Irvine Research Center, University of California Irvine, USA; Departments of Anatomy & Neurobiology, University of California Irvine, USA; School of Medicine, University of California Irvine, USA
| | - Jennifer M Yonan
- Reeve-Irvine Research Center, University of California Irvine, USA; Departments of Anatomy & Neurobiology, University of California Irvine, USA; School of Medicine, University of California Irvine, USA
| | - Kelly M Yee
- Reeve-Irvine Research Center, University of California Irvine, USA; Departments of Anatomy & Neurobiology, University of California Irvine, USA; School of Medicine, University of California Irvine, USA
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35
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Ashammakhi N, Kim HJ, Ehsanipour A, Bierman RD, Kaarela O, Xue C, Khademhosseini A, Seidlits SK. Regenerative Therapies for Spinal Cord Injury. TISSUE ENGINEERING PART B-REVIEWS 2019; 25:471-491. [PMID: 31452463 DOI: 10.1089/ten.teb.2019.0182] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Spinal cord injury (SCI) is a serious problem that primarily affects younger and middle-aged adults at its onset. To date, no effective regenerative treatment has been developed. Over the last decade, researchers have made significant advances in stem cell technology, biomaterials, nanotechnology, and immune engineering, which may be applied as regenerative therapies for the spinal cord. Although the results of clinical trials using specific cell-based therapies have proven safe, their efficacy has not yet been demonstrated. The pathophysiology of SCI is multifaceted, complex and yet to be fully understood. Thus, combinatorial therapies that simultaneously leverage multiple approaches will likely be required to achieve satisfactory outcomes. Although combinations of biomaterials with pharmacologic agents or cells have been explored, few studies have combined these modalities in a systematic way. For most strategies, clinical translation will be facilitated by the use of minimally invasive therapies, which are the focus of this review. In addition, this review discusses previously explored therapies designed to promote neuroregeneration and neuroprotection after SCI, while highlighting present challenges and future directions. Impact Statement To date there are no effective treatments that can regenerate the spinal cord after injury. Although there have been significant preclinical advances in bioengineering and regenerative medicine over the last decade, these have not translated into effective clinical therapies for spinal cord injury. This review focuses on minimally invasive therapies, providing extensive background as well as updates on recent technological developments and current clinical trials. This review is a comprehensive resource for researchers working towards regenerative therapies for spinal cord injury that will help guide future innovation.
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Affiliation(s)
- Nureddin Ashammakhi
- Division of Plastic Surgery, Department of Surgery, Oulu University, Oulu, Finland.,Center for Minimally Invasive Therapeutics (C-MIT), Los Angeles, California.,California NanoSystems Institute (CNSI), Los Angeles, California.,Department of Radiological Sciences, University of California, Los Angeles, Los Angeles, California.,Department of Bioengineering, University of California, Los Angeles, Los Angeles, California
| | - Han-Jun Kim
- Center for Minimally Invasive Therapeutics (C-MIT), Los Angeles, California.,California NanoSystems Institute (CNSI), Los Angeles, California.,Department of Bioengineering, University of California, Los Angeles, Los Angeles, California
| | | | | | - Outi Kaarela
- Division of Plastic Surgery, Department of Surgery, Oulu University, Oulu, Finland
| | - Chengbin Xue
- Center for Minimally Invasive Therapeutics (C-MIT), Los Angeles, California.,California NanoSystems Institute (CNSI), Los Angeles, California.,Department of Bioengineering, University of California, Los Angeles, Los Angeles, California.,Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, P.R. China.,Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong University, Nantong, P.R. China
| | - Ali Khademhosseini
- Center for Minimally Invasive Therapeutics (C-MIT), Los Angeles, California.,California NanoSystems Institute (CNSI), Los Angeles, California.,Department of Radiological Sciences, University of California, Los Angeles, Los Angeles, California.,Department of Bioengineering, University of California, Los Angeles, Los Angeles, California.,Center of Nanotechnology, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Chemical and Biological Engineering, University of California, Los Angeles, California
| | - Stephanie K Seidlits
- Center for Minimally Invasive Therapeutics (C-MIT), Los Angeles, California.,California NanoSystems Institute (CNSI), Los Angeles, California.,Jonsson Comprehensive Cancer Center, University of California, Los Angeles, Los Angeles, California.,Broad Stem Cell Research Center, University of California, Los Angeles, Los Angeles, California.,Brain Research Institute, University of California, Los Angeles, Los Angeles, California
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Barros Ribeiro da Silva V, Porcionatto M, Toledo Ribas V. The Rise of Molecules Able To Regenerate the Central Nervous System. J Med Chem 2019; 63:490-511. [PMID: 31518122 DOI: 10.1021/acs.jmedchem.9b00863] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Injury to the adult central nervous system (CNS) usually leads to permanent deficits of cognitive, sensory, and/or motor functions. The failure of axonal regeneration in the damaged CNS limits functional recovery. The lack of information concerning the biological mechanism of axonal regeneration and its complexity has delayed the process of drug discovery for many years compared to other drug classes. Starting in the early 2000s, the ability of many molecules to stimulate axonal regrowth was evaluated through automated screening techniques; many hits and some new mechanisms involved in axonal regeneration were identified. In this Perspective, we discuss the rise of the CNS regenerative drugs, the main biological techniques used to test these drug candidates, some of the most important screens performed so far, and the main challenges following the identification of a drug that is able to induce axonal regeneration in vivo.
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Affiliation(s)
| | - Marimélia Porcionatto
- Universidade Federal de São Paulo , Escola Paulista de Medicina, Laboratório de Neurobiologia Molecular, Departmento de Bioquímica , Rua Pedro de Toledo, 669 - third floor, 04039-032 São Paulo , São Paolo , Brazil
| | - Vinicius Toledo Ribas
- Universidade Federal de Minas Gerais , Instituto de Ciências Biológicas, Departamento de Morfologia, Laboratório de Neurobiologia Av. Antônio Carlos, 6627, room O3-245 , - Campus Pampulha, 31270-901 , Belo Horizonte , Minas Gerais , Brazil
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37
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Long-Distance Axon Regeneration Promotes Recovery of Diaphragmatic Respiratory Function after Spinal Cord Injury. eNeuro 2019; 6:ENEURO.0096-19.2019. [PMID: 31427403 PMCID: PMC6794082 DOI: 10.1523/eneuro.0096-19.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 06/11/2019] [Accepted: 06/14/2019] [Indexed: 12/14/2022] Open
Abstract
Compromise in inspiratory breathing following cervical spinal cord injury (SCI) is caused by damage to descending bulbospinal axons originating in the rostral ventral respiratory group (rVRG) and consequent denervation and silencing of phrenic motor neurons (PhMNs) that directly control diaphragm activation. In a rat model of high-cervical hemisection SCI, we performed systemic administration of an antagonist peptide directed against phosphatase and tensin homolog (PTEN), a central inhibitor of neuron-intrinsic axon growth potential. PTEN antagonist peptide (PAP4) robustly restored diaphragm function, as determined with electromyography (EMG) recordings in living SCI animals. PAP4 promoted substantial, long-distance regeneration of injured rVRG axons through the lesion and back toward PhMNs located throughout the C3–C5 spinal cord. These regrowing rVRG axons also formed putative excitatory synaptic connections with PhMNs, demonstrating reconnection of rVRG-PhMN-diaphragm circuitry. Lastly, re-lesion through the hemisection site completely ablated functional recovery induced by PAP4. Collectively, our findings demonstrate that axon regeneration in response to systemic PAP4 administration promoted recovery of diaphragmatic respiratory function after cervical SCI.
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38
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Guo S, Perets N, Betzer O, Ben-Shaul S, Sheinin A, Michaelevski I, Popovtzer R, Offen D, Levenberg S. Intranasal Delivery of Mesenchymal Stem Cell Derived Exosomes Loaded with Phosphatase and Tensin Homolog siRNA Repairs Complete Spinal Cord Injury. ACS NANO 2019; 13:10015-10028. [PMID: 31454225 DOI: 10.1021/acsnano.9b01892] [Citation(s) in RCA: 245] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Individuals with spinal cord injury (SCI) usually suffer from permanent neurological deficits, while spontaneous recovery and therapeutic efficacy are limited. Here, we demonstrate that when given intranasally, exosomes derived from mesenchymal stem cells (MSC-Exo) could pass the blood brain barrier and migrate to the injured spinal cord area. Furthermore, MSC-Exo loaded with phosphatase and tensin homolog small interfering RNA (ExoPTEN) could attenuate the expression of PTEN in the injured spinal cord region following intranasal administrations. In addition, the loaded MSC-Exo considerably enhanced axonal growth and neovascularization, while reducing microgliosis and astrogliosis. The intranasal ExoPTEN therapy could also partly improve structural and electrophysiological function and, most importantly, significantly elicited functional recovery in rats with complete SCI. The results imply that intranasal ExoPTEN may be used clinically to promote recovery for SCI individuals.
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Affiliation(s)
- Shaowei Guo
- Department of Biomedical Engineering , Technion-Israel Institute of Technology , Haifa 3200003 , Israel
- The First Affiliated Hospital , Shantou University Medical College , Shantou 515041 , China
| | | | - Oshra Betzer
- Faculty of Engineering and the Institute of Nanotechnology & Advanced Materials , Bar-Ilan University , Ramat Gan 5290002 , Israel
| | - Shahar Ben-Shaul
- Department of Biomedical Engineering , Technion-Israel Institute of Technology , Haifa 3200003 , Israel
| | | | - Izhak Michaelevski
- Department of Molecular Biology , Ariel University , Ariel 40700 , Israel
| | - Rachela Popovtzer
- Faculty of Engineering and the Institute of Nanotechnology & Advanced Materials , Bar-Ilan University , Ramat Gan 5290002 , Israel
| | | | - Shulamit Levenberg
- Department of Biomedical Engineering , Technion-Israel Institute of Technology , Haifa 3200003 , Israel
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39
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Xu AK, Gong Z, He YZ, Xia KS, Tao HM. Comprehensive therapeutics targeting the corticospinal tract following spinal cord injury. J Zhejiang Univ Sci B 2019; 20:205-218. [PMID: 30829009 DOI: 10.1631/jzus.b1800280] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Spinal cord injury (SCI), which is much in the public eye, is still a refractory disease compromising the well-being of both patients and society. In spite of there being many methods dealing with the lesion, there is still a deficiency in comprehensive strategies covering all facets of this damage. Further, we should also mention the structure called the corticospinal tract (CST) which plays a crucial role in the motor responses of organisms, and it will be the focal point of our attention. In this review, we discuss a variety of strategies targeting different dimensions following SCI and some treatments that are especially efficacious to the CST are emphasized. Over recent decades, researchers have developed many effective tactics involving five approaches: (1) tackle more extensive regions; (2) provide a regenerative microenvironment; (3) provide a glial microenvironment; (4) transplantation; and (5) other auxiliary methods, for instance, rehabilitation training and electrical stimulation. We review the basic knowledge on this disease and correlative treatments. In addition, some well-formulated perspectives and hypotheses have been delineated. We emphasize that such a multifaceted problem needs combinatorial approaches, and we analyze some discrepancies in past studies. Finally, for the future, we present numerous brand-new latent tactics which have great promise for curbing SCI.
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Affiliation(s)
- An-Kai Xu
- Department of Orthopedics, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China.,Orthopedics Research Institute of Zhejiang University, Hangzhou 310009, China
| | - Zhe Gong
- Department of Orthopedics, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China.,Orthopedics Research Institute of Zhejiang University, Hangzhou 310009, China
| | - Yu-Zhe He
- Department of Orthopedics, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China.,Orthopedics Research Institute of Zhejiang University, Hangzhou 310009, China
| | - Kai-Shun Xia
- Department of Orthopedics, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China.,Orthopedics Research Institute of Zhejiang University, Hangzhou 310009, China
| | - Hui-Min Tao
- Department of Orthopedics, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China.,Orthopedics Research Institute of Zhejiang University, Hangzhou 310009, China
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40
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Erwin A, Gallegos C, Cao Q, O'Malley MK. A Robotic Platform for 3D Forelimb Rehabilitation with Rats. IEEE Int Conf Rehabil Robot 2019; 2019:429-434. [PMID: 31374667 DOI: 10.1109/icorr.2019.8779405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In an attempt to promote greater functional recovery after spinal cord injury, researchers have begun exploring combinatorial treatments, such as robotic rehabilitation combined with stem cell transplantation. Since these treatment methods are in their nascent stages, rodent models have been proposed for initial investigations. Robots have been built for locomotion rehabilitation and planar forelimb reach and grasp assessment with rodents; however, a robotic platform suitable for three-dimensional movement rehabilitation of the rodent forelimb has not yet been developed. In this paper, a novel three degree of freedom robotic manipulator for automated forelimb rehabilitation combined with stem cell transplantation after cervical spinal cord injury with rats is proposed. The robot interfaces with a rat in an end-effector manner, measuring and interacting with the forelimb in the 3D Cartesian space. In this work, we trained two rats through behavioral shaping to actively interact with the device during two robot control modes. This work provides preliminary investigations into the feasibility of 3D forelimb rehabilitation with rats, which could be translated as a paradigm for combinatorial treatments after spinal cord injury in a controlled manner.
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41
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Walker CL, Wu X, Liu NK, Xu XM. Bisperoxovanadium Mediates Neuronal Protection through Inhibition of PTEN and Activation of PI3K/AKT-mTOR Signaling after Traumatic Spinal Injuries. J Neurotrauma 2019; 36:2676-2687. [PMID: 30672370 DOI: 10.1089/neu.2018.6294] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Although mechanisms involved in progression of cell death in spinal cord injury (SCI) have been studied extensively, few are clear targets for translation to clinical application. One of the best-understood mechanisms of cell survival in SCI is phosphatidylinositol-3-kinase (PI3K)/Akt and associated downstream signaling. Clear therapeutic efficacy of a phosphatase and tensin homologue (PTEN) inhibitor called bisperoxovanadium (bpV) has been shown in SCI, traumatic brain injury, stroke, and other neurological disease models in both neuroprotection and functional recovery. The present study aimed to elucidate mechanistic influences of bpV activity in neuronal survival in in vitro and in vivo models of SCI. Treatment with 100 nM bpV(pic) reduced cell death in a primary spinal neuron injury model (p < 0.05) in vitro, and upregulated both Akt and ribosomal protein S6 (pS6) activity (p < 0.05) compared with non-treated injured neurons. Pre-treatment of spinal neurons with a PI3K inhibitor, LY294002 or mammalian target of rapamycin (mTOR) inhibitor, rapamycin blocked bpV activation of Akt and ribosomal protein S6 activity, respectively. Treatment with bpV increased extracellular signal-related kinase (Erk) activity after scratch injury in vitro, and rapamycin reduced influence by bpV on Erk phosphorylation. After a cervical hemicontusive SCI, Akt phosphorylation decreased in total tissue via Western blot analysis (p < 0.01) as well as in penumbral ventral horn motor neurons throughout the first week post-injury (p < 0.05). Conversely, PTEN activity appeared to increase over this period. As observed in vitro, bpV also increased Erk activity post-SCI (p < 0.05). Our results suggest that PI3K/Akt signaling is the likely primary mechanism of bpV action in mediating neuroprotection in injured spinal neurons.
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Affiliation(s)
- Chandler L Walker
- Department of Biomedical and Applied Sciences, Indiana University School of Dentistry, Indianapolis, Indiana.,Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery and Goodman Campbell Brain and Spine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Xiangbing Wu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery and Goodman Campbell Brain and Spine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Nai-Kui Liu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery and Goodman Campbell Brain and Spine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Xiao-Ming Xu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery and Goodman Campbell Brain and Spine, Indiana University School of Medicine, Indianapolis, Indiana
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42
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Li X, Liu D, Xiao Z, Zhao Y, Han S, Chen B, Dai J. Scaffold-facilitated locomotor improvement post complete spinal cord injury: Motor axon regeneration versus endogenous neuronal relay formation. Biomaterials 2019; 197:20-31. [PMID: 30639547 DOI: 10.1016/j.biomaterials.2019.01.012] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 12/10/2018] [Accepted: 01/05/2019] [Indexed: 01/18/2023]
Abstract
Complete transected spinal cord injury (SCI) severely influences the quality of life and mortality rates of animals and patients. In the past decade, many simple and combinatorial therapeutic treatments have been tested in improving locomotor function in animals with this extraordinarily challenging SCI. The potential mechanism for promotion of locomotor function relies either on direct motor axon regeneration through the lesion gap or indirect neuronal relay bridging to functionally reconnect transected spinal stumps. In this review, we first compare the advantages and problems of complete transection SCI animal models with other prevailing SCI models used in motor axon regeneration research. Next, we enumerate some of the popular bio-scaffolds utilized in complete SCI repair in the last decade. Then, the current state of motor axon regeneration as well as its role on locomotor improvement of animals after complete SCI is discussed. Last, the current approach of directing endogenous neuronal relays formation to achieve motor function recovery by well-designed functional bio-scaffolds implantation in complete transected SCI animals is reviewed. Although facilitating neuronal relays formation by bio-scaffolds implantation appears to be more practical and feasible than directing motor axon regeneration in promoting locomotor outcome in animals after complete SCI, there are still challenges in neuronal relays formation, maintaining and debugging for spinal cord regenerative repair.
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Affiliation(s)
- Xing Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Xiangya Hospital, Central South University (CSU), Changsha, Hunan, 410008, China
| | - Dingyang Liu
- Department of Neurosurgery, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha 410008, Hunan Province, China
| | - Zhifeng Xiao
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yannan Zhao
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Sufang Han
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Bing Chen
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jianwu Dai
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
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43
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Yuan H, Hu Y, Jiang L, Wang T. The research progress of miRNA/lncRNA associated with spinal cord injury. IBRAIN 2019. [DOI: 10.1002/j.2769-2795.2019.tb00042.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Hao Yuan
- Department of Spinal SurgeryAffiliated Hospital of Zunyi Medical UniversityZunyiGuizhouChina
| | - Yue Hu
- Department of Anesthesiology and Institute of Neurological DiseaseTranslational Neuroscience Center, West China Hospital, Sichuan UniversityChengduSichuanChina
| | - Ling Jiang
- Department of Anesthesiology and Institute of Neurological DiseaseTranslational Neuroscience Center, West China Hospital, Sichuan UniversityChengduSichuanChina
| | - Ting‐Hua Wang
- Department of Anesthesiology and Institute of Neurological DiseaseTranslational Neuroscience Center, West China Hospital, Sichuan UniversityChengduSichuanChina
- Institute of Neuroscience, Kunming Medical UniversityKunmingYunnanChina
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44
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Mukhamedshina YO, Gracheva OA, Mukhutdinova DM, Chelyshev YA, Rizvanov AA. Mesenchymal stem cells and the neuronal microenvironment in the area of spinal cord injury. Neural Regen Res 2019; 14:227-237. [PMID: 30531002 PMCID: PMC6301181 DOI: 10.4103/1673-5374.244778] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Cell-based technologies are used as a therapeutic strategy in spinal cord injury (SCI). Mesenchymal stem cells (MSCs), which secrete various neurotrophic factors and cytokines, have immunomodulatory, anti-apoptotic and anti-inflammatory effects, modulate reactivity/phenotype of astrocytes and the microglia, thereby promoting neuroregeneration seem to be the most promising. The therapeutic effect of MSCs is due to a paracrine mechanism of their action, therefore the survival of MSCs and their secretory phenotype is of particular importance. Nevertheless, these data are not always reported in efficacy studies of MSC therapy in SCI. Here, we provide a review with summaries of preclinical trials data evaluating the efficacy of MSCs in animal models of SCI. Based on the data collected, we have tried (1) to establish the behavior of MSCs after transplantation in SCI with an evaluation of cell survival, migration potential, distribution in the area of injured and intact tissue and possible differentiation; (2) to determine the effects MSCs on neuronal microenvironment and correlate them with the efficacy of functional recovery in SCI; (3) to ascertain the conditions under which MSCs demonstrate their best survival and greatest efficacy.
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Affiliation(s)
- Yana O Mukhamedshina
- OpenLab Gene and Cell Technologies, Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University; Department of Histology, Cytology and Embryology, Kazan State Medical University, Kazan, Russia
| | - Olga A Gracheva
- Department of Therapy and Clinical Diagnostics with radiology Faculty of Veterinary Medicine, Bauman Kazan State Academy of Veterinary Medicine, Kazan, Russia
| | - Dina M Mukhutdinova
- Department of Therapy and Clinical Diagnostics with radiology Faculty of Veterinary Medicine, Bauman Kazan State Academy of Veterinary Medicine, Kazan, Russia
| | - Yurii A Chelyshev
- Department of Histology, Cytology and Embryology, Kazan State Medical University, Kazan, Russia
| | - Albert A Rizvanov
- OpenLab Gene and Cell Technologies, Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, Kazan, Russia
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Xu G, Ao R, Zhi Z, Jia J, Yu B. miR‐21 and miR‐19b delivered by hMSC‐derived EVs regulate the apoptosis and differentiation of neurons in patients with spinal cord injury. J Cell Physiol 2018; 234:10205-10217. [PMID: 30387159 DOI: 10.1002/jcp.27690] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Accepted: 10/09/2018] [Indexed: 12/21/2022]
Affiliation(s)
- Guanghui Xu
- Orthopedics Department , Shanghai Pudong Hospital, Fudan University Pudong Medical Center Pudong Shanghai China
| | - Rongguang Ao
- Orthopedics Department , Shanghai Pudong Hospital, Fudan University Pudong Medical Center Pudong Shanghai China
| | - Zhongzheng Zhi
- Orthopedics Department , Shanghai Pudong Hospital, Fudan University Pudong Medical Center Pudong Shanghai China
| | - Jianbo Jia
- Orthopedics Department , Shanghai Pudong Hospital, Fudan University Pudong Medical Center Pudong Shanghai China
| | - Baoqing Yu
- Orthopedics Department , Shanghai Pudong Hospital, Fudan University Pudong Medical Center Pudong Shanghai China
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Ohtake Y, Sami A, Jiang X, Horiuchi M, Slattery K, Ma L, Smith GM, Selzer ME, Muramatsu SI, Li S. Promoting Axon Regeneration in Adult CNS by Targeting Liver Kinase B1. Mol Ther 2018; 27:102-117. [PMID: 30509565 DOI: 10.1016/j.ymthe.2018.10.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 10/24/2018] [Accepted: 10/26/2018] [Indexed: 12/21/2022] Open
Abstract
Liver kinase B1 (LKB1), a downstream effector of cyclic AMP (cAMP)/PKA and phosphatidylinositol 3-kinase (PI3K) pathways, is a determinant for migration and differentiation of many cells, but its role in CNS axon regeneration is unknown. Therefore, LKB1 was overexpressed in sensorimotor cortex of adult mice five days after mid-thoracic spinal cord injury, using an AAV2 vector. Regeneration of corticospinal axons was dramatically enhanced. Next, systemic injection of a mutant-AAV9 vector was used to upregulate LKB1 specifically in neurons. This promoted long-distance regeneration of injured corticospinal fibers into caudal spinal cord in adult mice and regrowth of descending serotonergic and tyrosine hydroxylase immunoreactive axons. Either intracortical or systemic viral delivery of LKB1 significantly improved recovery of locomotor functions in adult mice with spinal cord injury. Moreover, we demonstrated that LKB1 used AMPKα, NUAK1, and ERK as the downstream effectors in the cortex of adult mice. Thus, LKB1 may be a critical factor for enhancing the growth capacity of mature neurons and may be an important molecular target in the treatment of CNS injuries.
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Affiliation(s)
- Yosuke Ohtake
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA; Department of Anatomy and Cell Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Armin Sami
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA; Department of Anatomy and Cell Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Xinpei Jiang
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA; Department of Anatomy and Cell Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Makoto Horiuchi
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA; Department of Anatomy and Cell Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Kieran Slattery
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA; Department of Anatomy and Cell Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Lena Ma
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA; Department of Anatomy and Cell Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - George M Smith
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA; Department of Neuroscience, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Michael E Selzer
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA; Department of Neurology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Shin-Ichi Muramatsu
- Division of Neurology, Jichi Medical University, Shimotsuke, Tochigi 329-0498, Japan
| | - Shuxin Li
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA; Department of Anatomy and Cell Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA.
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Yu B, Gu X. Combination of biomaterial transplantation and genetic enhancement of intrinsic growth capacities to promote CNS axon regeneration after spinal cord injury. Front Med 2018; 13:131-137. [PMID: 30159670 DOI: 10.1007/s11684-018-0642-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 04/26/2018] [Indexed: 12/16/2022]
Abstract
The inhibitory environment that surrounds the lesion site and the lack of intrinsic regenerative capacity of the adult mammalian central nervous system (CNS) impede the regrowth of injured axons and thereby the reestablishment of neural circuits required for functional recovery after spinal cord injuries (SCI). To circumvent these barriers, biomaterial scaffolds are applied to bridge the lesion gaps for the regrowing axons to follow, and, often by combining stem cell transplantation, to enable the local environment in the growth-supportive direction. Manipulations, such as the modulation of PTEN/mTOR pathways, can also enhance intrinsic CNS axon regrowth after injury. Given the complex pathophysiology of SCI, combining biomaterial scaffolds and genetic manipulation may provide synergistic effects and promote maximal axonal regrowth. Future directions will primarily focus on the translatability of these approaches and promote therapeutic avenues toward the functional rehabilitation of patients with SCIs.
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Affiliation(s)
- Bin Yu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - Xiaosong Gu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China.
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Li J, Li X, Xiao Z, Dai J. [Review of the regeneration mechanism of complete spinal cord injury]. ZHONGGUO XIU FU CHONG JIAN WAI KE ZA ZHI = ZHONGGUO XIUFU CHONGJIAN WAIKE ZAZHI = CHINESE JOURNAL OF REPARATIVE AND RECONSTRUCTIVE SURGERY 2018; 32:641-649. [PMID: 29905039 DOI: 10.7507/1002-1892.201805069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Spinal cord injury (SCI), especially the complete SCI, usually results in complete paralysis below the level of the injury and seriously affects the patient's quality of life. SCI repair is still a worldwide medical problem. In the last twenty years, Professor DAI Jianwu and his team pioneered complete SCI model by removing spinal tissue with varied lengths in rodents, canine, and non-human primates to verify therapeutic effect of different repair strategies. Moreover, they also started the first clinical study of functional collagen scaffold on patients with acute complete SCI on January 16th, 2015. This review mainly focusses on the possible mechanisms responsible for complete SCI. In common, recovery of some sensory and motor functions post complete SCI include the following three contributing reasons. ① Regeneration of long ascending and descending axons throughout the lesion site to re-connect the original targets; ② New neural circuits formed in the lesion site by newly generated neurons post injury, which effectively re-connect the transected stumps; ③ The combined effect of ① and ②. The numerous studies have confirmed that neural circuits rebuilt across the injury site by newborn neurons might be the main mechanisms for functional recovery of animals from rodents to dogs. In many SCI model, especially the complete spinal cord transection model, many studies have convincingly demonstrated that the quantity and length of regenerated long descending axons, particularly like CST fibers, are too few to across the lesion site that is millimeters in length to realize motor functional recovery. Hence, it is more feasible in guiding neuronal relays formation by bio-scaffolds implantation than directing long motor axons regeneration in improving motor function of animals with complete spinal cord transection. However, some other issues such as promoting more neuronal relays formation, debugging wrong connections, and maintaining adequate neural circuits for functional recovery are urgent problems to be addressed.
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Affiliation(s)
- Jiayin Li
- Institute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing, 100101,P.R.China
| | - Xing Li
- Institute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing, 100101,P.R.China
| | - Zhifeng Xiao
- Institute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing, 100101,P.R.China
| | - Jianwu Dai
- Institute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing, 100101,
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Zareen N, Dodson S, Armada K, Awad R, Sultana N, Hara E, Alexander H, Martin JH. Stimulation-dependent remodeling of the corticospinal tract requires reactivation of growth-promoting developmental signaling pathways. Exp Neurol 2018; 307:133-144. [PMID: 29729248 DOI: 10.1016/j.expneurol.2018.05.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 03/18/2018] [Accepted: 05/01/2018] [Indexed: 12/13/2022]
Abstract
The corticospinal tract (CST) can become damaged after spinal cord injury or stroke, resulting in weakness or paralysis. Repair of the damaged CST is limited because mature CST axons fail to regenerate, which is partly because the intrinsic axon growth capacity is downregulated in maturity. Whereas CST axons sprout after injury, this is insufficient to recover lost functions. Chronic motor cortex (MCX) electrical stimulation is a neuromodulatory strategy to promote CST axon sprouting, leading to functional recovery after CST lesion. Here we examine the molecular mechanisms of stimulation-dependent CST axonal sprouting and synapse formation. MCX stimulation rapidly upregulates mTOR and Jak/Stat signaling in the corticospinal system. Chronic stimulation, which leads to CST sprouting and increased CST presynaptic sites, further enhances mTOR and Jak/Stat activity. Importantly, chronic stimulation shifts the equilibrium of the mTOR repressor PTEN to the inactive phosphorylated form suggesting a molecular transition to an axon growth state. We blocked each signaling pathway selectively to determine potential differential contributions to axonal outgrowth and synapse formation. mTOR blockade prevented stimulation-dependent axon sprouting. Surprisingly, Jak/Stat blockade did not abrogate sprouting, but instead prevented the increase in CST presynaptic sites produced by chronic MCX stimulation. Chronic stimulation increased the number of spinal neurons expressing the neural activity marker cFos. Jak/Stat blockade prevented the increase in cFos-expressing neurons after chronic stimulation, confirming an important role for Jak/Stat signaling in activity-dependent CST synapse formation. MCX stimulation is a neuromodulatory repair strategy that reactivates distinct developmentally-regulated signaling pathways for axonal outgrowth and synapse formation.
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Affiliation(s)
- Neela Zareen
- Department of Molecular, Cellular, and Basic Medical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA
| | - Shahid Dodson
- Department of Molecular, Cellular, and Basic Medical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA
| | - Kristine Armada
- Department of Molecular, Cellular, and Basic Medical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA
| | - Rahma Awad
- Department of Molecular, Cellular, and Basic Medical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA
| | - Nadia Sultana
- Department of Molecular, Cellular, and Basic Medical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA
| | - Erina Hara
- Department of Molecular, Cellular, and Basic Medical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA
| | - Heather Alexander
- Department of Molecular, Cellular, and Basic Medical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA
| | - John H Martin
- Department of Molecular, Cellular, and Basic Medical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA; Neuroscience Program, Graduate Center of the City University of New York, New York, NY, USA.
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50
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Gallaher ZR, Steward O. Modest enhancement of sensory axon regeneration in the sciatic nerve with conditional co-deletion of PTEN and SOCS3 in the dorsal root ganglia of adult mice. Exp Neurol 2018; 303:120-133. [PMID: 29458059 DOI: 10.1016/j.expneurol.2018.02.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 01/09/2018] [Accepted: 02/15/2018] [Indexed: 11/25/2022]
Abstract
Axons within the peripheral nervous system are capable of regeneration, but full functional recovery is rare. Recent work has shown that conditional deletion of two key signaling inhibitors of the PI3K and Jak/Stat pathways-phosphatase and tensin homolog (PTEN) and suppressor of cytokine signaling-3 (SOCS3), respectively-promotes regeneration of normally non-regenerative central nervous system axons. Moreover, in studies of optic nerve regeneration, co-deletion of both PTEN and SOCS3 has an even greater effect. Here, we test the hypotheses (1) that PTEN deletion enhances axon regeneration following sciatic nerve crush and (2) that PTEN/SOCS3 co-deletion further promotes regeneration. PTENfl/fl and PTEN/SOCS3fl/fl mice received direct injections of AAV-Cre into the fourth and fifth lumbar dorsal root ganglia (DRG) two weeks prior to sciatic nerve crush. Western blot analysis of whole cell lysates from DRG using phospho-specific antibodies revealed that PTEN deletion did not enhance or prolong PI3K signaling following sciatic nerve crush. However, PTEN/SOCS3 co-deletion activated PI3K for at least 7 days post-injury in contrast to controls, where activation peaked at 3 days. Quantification of SCG10-expressing regenerating sensory axons in the sciatic nerve after crush injury revealed longer distance regeneration at 3 days post-injury with both PTEN and PTEN/SOCS3 co-deletion. Additionally, analysis of noxious thermosensation and mechanosensation with PTEN/SOCS3 co-deletion revealed enhanced sensation at 14 and 21 days after crush, respectively, after which all treatment groups reached the same functional plateau. These findings indicate that co-deletion of PTEN and SOCS3 results in modest but measureable enhancement of early regeneration of DRG axons following crush injury.
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Affiliation(s)
- Zachary R Gallaher
- Reeve-Irvine Research Center, Department of Anatomy and Neurobiology, School of Medicine, University of California Irvine, Irvine, CA 92697, USA.
| | - Oswald Steward
- Reeve-Irvine Research Center, Department of Anatomy and Neurobiology, School of Medicine, University of California Irvine, Irvine, CA 92697, USA; Department of Neurobiology and Behavior, Department of Neurosurgery, University of California Irvine, Irvine, CA 92697, USA.
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