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Curran BM, Nickerson KR, Yung AR, Goodrich LV, Jaworski A, Tessier-Lavigne M, Ma L. Multiple Guidance Mechanisms Control Axon Growth to Generate Precise T-shaped Bifurcation during Dorsal Funiculus Development in the Spinal Cord. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.17.567638. [PMID: 38014092 PMCID: PMC10680847 DOI: 10.1101/2023.11.17.567638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
The dorsal funiculus in the spinal cord relays somatosensory information to the brain. It is made of T-shaped bifurcation of dorsal root ganglion (DRG) sensory axons. Our previous study has shown that Slit signaling is required for proper guidance during bifurcation, but loss of Slit does not affect all DRG axons. Here, we examined the role of the extracellular molecule Netrin-1 (Ntn1). Using wholemount staining with tissue clearing, we showed that mice lacking Ntn1 have axons escaping from the dorsal funiculus at the time of bifurcation. Genetic labeling confirmed that these misprojecting axons come from DRG neurons. Single axon analysis showed that loss of Ntn1 does not affect bifurcation but rather alters turning angles. To distinguish their guidance functions, we examined mice with triple deletion of Ntn1, Slit1, and Slit2 and found a completely disorganized dorsal funiculus. Comparing mice with different genotypes using immunolabeling and single axon tracing revealed additive guidance errors, demonstrating the independent roles of Ntn1 and Slit. Moreover, the same defects were observed in embryos lacking their cognate receptors. These in vivo studies thus demonstrate the presence of multi-factorial guidance mechanisms that ensure proper formation of a common branched axonal structure during spinal cord development.
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Affiliation(s)
- Bridget M Curran
- Department of Neuroscience, Jefferson Synaptic Biology Center, Vickie and Jack Farber Institute for Neuroscience, Sydney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107
| | - Kelsey R Nickerson
- Department of Neuroscience, Brown University, Providence, RI 02912
- Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI 02912
| | - Andrea R Yung
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115
| | - Lisa V Goodrich
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115
| | - Alexander Jaworski
- Department of Neuroscience, Brown University, Providence, RI 02912
- Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI 02912
| | | | - Le Ma
- Department of Neuroscience, Jefferson Synaptic Biology Center, Vickie and Jack Farber Institute for Neuroscience, Sydney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107
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2
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Galli R, Uckermann O. Vibrational spectroscopy and multiphoton microscopy for label-free visualization of nervous system degeneration and regeneration. Biophys Rev 2024; 16:219-235. [PMID: 38737209 PMCID: PMC11078905 DOI: 10.1007/s12551-023-01158-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 09/22/2023] [Indexed: 05/14/2024] Open
Abstract
Neurological disorders, including spinal cord injury, peripheral nerve injury, traumatic brain injury, and neurodegenerative diseases, pose significant challenges in terms of diagnosis, treatment, and understanding the underlying pathophysiological processes. Label-free multiphoton microscopy techniques, such as coherent Raman scattering, two-photon excited autofluorescence, and second and third harmonic generation microscopy, have emerged as powerful tools for visualizing nervous tissue with high resolution and without the need for exogenous labels. Coherent Raman scattering processes as well as third harmonic generation enable label-free visualization of myelin sheaths, while their combination with two-photon excited autofluorescence and second harmonic generation allows for a more comprehensive tissue visualization. They have shown promise in assessing the efficacy of therapeutic interventions and may have future applications in clinical diagnostics. In addition to multiphoton microscopy, vibrational spectroscopy methods such as infrared and Raman spectroscopy offer insights into the molecular signatures of injured nervous tissues and hold potential as diagnostic markers. This review summarizes the application of these label-free optical techniques in preclinical models and illustrates their potential in the diagnosis and treatment of neurological disorders with a special focus on injury, degeneration, and regeneration. Furthermore, it addresses current advancements and challenges for bridging the gap between research findings and their practical applications in a clinical setting.
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Affiliation(s)
- Roberta Galli
- Medical Physics and Biomedical Engineering, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
| | - Ortrud Uckermann
- Department of Neurosurgery, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
- Division of Medical Biology, Department of Psychiatry and Psychotherapy, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
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Deng J, Sun C, Zheng Y, Gao J, Cui X, Wang Y, Zhang L, Tang P. In vivo imaging of the neuronal response to spinal cord injury: a narrative review. Neural Regen Res 2024; 19:811-817. [PMID: 37843216 PMCID: PMC10664102 DOI: 10.4103/1673-5374.382225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 05/15/2023] [Accepted: 07/07/2023] [Indexed: 10/17/2023] Open
Abstract
Deciphering the neuronal response to injury in the spinal cord is essential for exploring treatment strategies for spinal cord injury (SCI). However, this subject has been neglected in part because appropriate tools are lacking. Emerging in vivo imaging and labeling methods offer great potential for observing dynamic neural processes in the central nervous system in conditions of health and disease. This review first discusses in vivo imaging of the mouse spinal cord with a focus on the latest imaging techniques, and then analyzes the dynamic biological response of spinal cord sensory and motor neurons to SCI. We then summarize and compare the techniques behind these studies and clarify the advantages of in vivo imaging compared with traditional neuroscience examinations. Finally, we identify the challenges and possible solutions for spinal cord neuron imaging.
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Affiliation(s)
- Junhao Deng
- Department of Orthopedics, The Fourth Medical Center of Chinese PLA General Hospital, Beijing, China
- National Clinical Research Center for Orthopedics, Sports Medicine and Rehabilitation, Beijing, China
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Chang Sun
- Department of Orthopedics, The Fourth Medical Center of Chinese PLA General Hospital, Beijing, China
- National Clinical Research Center for Orthopedics, Sports Medicine and Rehabilitation, Beijing, China
- Department of Orthopedics, Air Force Medical Center, PLA, Beijing, China
| | - Ying Zheng
- Medical School of Chinese PLA, Beijing, China
| | - Jianpeng Gao
- Department of Orthopedics, The Fourth Medical Center of Chinese PLA General Hospital, Beijing, China
- National Clinical Research Center for Orthopedics, Sports Medicine and Rehabilitation, Beijing, China
| | - Xiang Cui
- Department of Orthopedics, The Fourth Medical Center of Chinese PLA General Hospital, Beijing, China
- National Clinical Research Center for Orthopedics, Sports Medicine and Rehabilitation, Beijing, China
| | - Yu Wang
- Institute of Orthopedics, The First Medical Center, Chinese PLA General Hospital, Beijing, China
- Key Lab of Regenerative Medicine in Orthopedics, Key Laboratory of Musculoskeletal Trauma and War Injuries PLA, Beijing, China
| | - Licheng Zhang
- Department of Orthopedics, The Fourth Medical Center of Chinese PLA General Hospital, Beijing, China
- National Clinical Research Center for Orthopedics, Sports Medicine and Rehabilitation, Beijing, China
| | - Peifu Tang
- Department of Orthopedics, The Fourth Medical Center of Chinese PLA General Hospital, Beijing, China
- National Clinical Research Center for Orthopedics, Sports Medicine and Rehabilitation, Beijing, China
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Zhao Q, Jiang C, Zhao L, Dai X, Yi S. Unleashing Axonal Regeneration Capacities: Neuronal and Non-neuronal Changes After Injuries to Dorsal Root Ganglion Neuron Central and Peripheral Axonal Branches. Mol Neurobiol 2024; 61:423-433. [PMID: 37620687 DOI: 10.1007/s12035-023-03590-7] [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: 02/23/2023] [Accepted: 08/16/2023] [Indexed: 08/26/2023]
Abstract
Peripheral nerves obtain remarkable regenerative capacity while central nerves can hardly regenerate following nerve injury. Sensory neurons in the dorsal root ganglion (DRG) are widely used to decipher the dissimilarity between central and peripheral axonal regeneration as axons of DRG neurons bifurcate into the regeneration-incompetent central projections and the regeneration-competent peripheral projections. A conditioning peripheral branch injury facilitates central axonal regeneration and enables the growth and elongation of central axons. Peripheral axonal injury stimulates neuronal calcium influx, alters the start-point chromatin states, increases chromatin accessibility, upregulates the expressions of regeneration-promoting genes and the synthesis of proteins, and supports axonal regeneration. Following central axonal injury, the responses of DRG neurons are modest, resulting in poor intrinsic growth ability. Some non-neuronal cells in DRGs, for instance satellite glial cells, also exhibit diminished injury responses to central axon injury as compared with peripheral axon injury. Moreover, DRG central and peripheral axonal branches are respectively surrounded by inhibitory glial scars generated by central glial cells and a permissive microenvironment generated by Schwann cells and macrophages. The aim of this review is to look at changes of DRG neurons and non-neuronal cells after peripheral and central axon injuries and summarize the contributing roles of both neuronal intrinsic regenerative capacities and surrounding microenvironments in axonal regeneration.
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Affiliation(s)
- Qian Zhao
- 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, China
| | - Chunyi Jiang
- 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, China
- Department of Pathology, Nantong University Affiliated Hospital, Nantong, Jiangsu, China
| | - Li Zhao
- 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, China
| | - Xiu Dai
- 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, China.
| | - Sheng Yi
- 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, China.
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Monroy GL, Erfanzadeh M, Tao M, DePaoli DT, Saytashev I, Nam SA, Rafi H, Kwong KC, Shea K, Vakoc BJ, Vasudevan S, Hammer DX. Development of polarization-sensitive optical coherence tomography imaging platform and metrics to quantify electrostimulation-induced peripheral nerve injury in vivo in a small animal model. NEUROPHOTONICS 2023; 10:025004. [PMID: 37077218 PMCID: PMC10109528 DOI: 10.1117/1.nph.10.2.025004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 03/28/2023] [Indexed: 05/03/2023]
Abstract
Significance Neuromodulation devices are rapidly evolving for the treatment of neurological diseases and conditions. Injury from implantation or long-term use without obvious functional losses is often only detectable through terminal histology. New technologies are needed that assess the peripheral nervous system (PNS) under normal and diseased or injured conditions. Aim We aim to demonstrate an imaging and stimulation platform that can elucidate the biological mechanisms and impacts of neurostimulation in the PNS and apply it to the sciatic nerve to extract imaging metrics indicating electrical overstimulation. Approach A sciatic nerve injury model in a 15-rat cohort was observed using a newly developed imaging and stimulation platform that can detect electrical overstimulation effects with polarization-sensitive optical coherence tomography. The sciatic nerve was electrically stimulated using a custom-developed nerve holder with embedded electrodes for 1 h, followed by a 1-h recovery period, delivered at above-threshold Shannon model k -values in experimental groups: sham control (SC, n = 5 , 0.0 mA / 0 Hz ), stimulation level 1 (SL1, n = 5 , 3.4 mA / 50 Hz , and k = 2.57 ), and stimulation level 2 (SL2, n = 5 , 6.8 mA / 100 Hz , and k = 3.17 ). Results The stimulation and imaging system successfully captured study data across the cohort. When compared to a SC after a 1-week recovery, the fascicle closest to the stimulation lead showed an average change of + 4 % / - 309 % (SL1/SL2) in phase retardation and - 79 % / - 148 % in optical attenuation relative to SC. Analysis of immunohistochemistry (IHC) shows a + 1 % / - 36 % difference in myelin pixel counts and - 13 % / + 29 % difference in axon pixel counts, and an overall increase in cell nuclei pixel count of + 20 % / + 35 % . These metrics were consistent with IHC and hematoxylin/eosin tissue section analysis. Conclusions The poststimulation changes observed in our study are manifestations of nerve injury and repair, specifically degeneration and angiogenesis. Optical imaging metrics quantify these processes and may help evaluate the safety and efficacy of neuromodulation devices.
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Affiliation(s)
- Guillermo L. Monroy
- U. S. Food and Drug Administration, Center for Devices and Radiological Health, Office of Science and Engineering Laboratories, Division of Biomedical Physics, Silver Spring, Maryland, United States
| | - Mohsen Erfanzadeh
- Massachusetts General Hospital, Harvard Medical School, Wellman Center for Photomedicine, Boston, Massachusetts, United States
- Harvard Medical School, Boston, Massachusetts, United States
| | - Michael Tao
- U. S. Food and Drug Administration, Center for Devices and Radiological Health, Office of Science and Engineering Laboratories, Division of Biomedical Physics, Silver Spring, Maryland, United States
| | - Damon T. DePaoli
- Massachusetts General Hospital, Harvard Medical School, Wellman Center for Photomedicine, Boston, Massachusetts, United States
- Harvard Medical School, Boston, Massachusetts, United States
| | - Ilyas Saytashev
- U. S. Food and Drug Administration, Center for Devices and Radiological Health, Office of Science and Engineering Laboratories, Division of Biomedical Physics, Silver Spring, Maryland, United States
| | - Stephanie A. Nam
- Massachusetts General Hospital, Harvard Medical School, Wellman Center for Photomedicine, Boston, Massachusetts, United States
- Harvard Medical School, Boston, Massachusetts, United States
| | - Harmain Rafi
- U. S. Food and Drug Administration, Center for Devices and Radiological Health, Office of Science and Engineering Laboratories, Division of Biomedical Physics, Silver Spring, Maryland, United States
| | - Kasey C. Kwong
- Massachusetts General Hospital, Harvard Medical School, Wellman Center for Photomedicine, Boston, Massachusetts, United States
- Harvard Medical School, Boston, Massachusetts, United States
| | - Katherine Shea
- U. S. Food and Drug Administration, Center for Drug Evaluation and Research, Office of Clinical Pharmacology, Office of Translational Science, Division of Applied Regulatory Science, Silver Spring, Maryland, United States
| | - Benjamin J. Vakoc
- Massachusetts General Hospital, Harvard Medical School, Wellman Center for Photomedicine, Boston, Massachusetts, United States
- Harvard Medical School, Boston, Massachusetts, United States
- Massachusetts Institute of Technology, Division of Health Science and Technology, Cambridge, Massachusetts, United States
| | - Srikanth Vasudevan
- U. S. Food and Drug Administration, Center for Devices and Radiological Health, Office of Science and Engineering Laboratories, Division of Biomedical Physics, Silver Spring, Maryland, United States
- Address all correspondence to Srikanth Vasudevan, ; Daniel X. Hammer,
| | - Daniel X. Hammer
- U. S. Food and Drug Administration, Center for Devices and Radiological Health, Office of Science and Engineering Laboratories, Division of Biomedical Physics, Silver Spring, Maryland, United States
- Address all correspondence to Srikanth Vasudevan, ; Daniel X. Hammer,
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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: 27] [Impact Index Per Article: 27.0] [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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Avraham O, Feng R, Ewan EE, Rustenhoven J, Zhao G, Cavalli V. Profiling sensory neuron microenvironment after peripheral and central axon injury reveals key pathways for neural repair. eLife 2021; 10:e68457. [PMID: 34586065 PMCID: PMC8480984 DOI: 10.7554/elife.68457] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 09/12/2021] [Indexed: 12/19/2022] Open
Abstract
Sensory neurons with cell bodies in dorsal root ganglia (DRG) represent a useful model to study axon regeneration. Whereas regeneration and functional recovery occurs after peripheral nerve injury, spinal cord injury or dorsal root injury is not followed by regenerative outcomes. Regeneration of sensory axons in peripheral nerves is not entirely cell autonomous. Whether the DRG microenvironment influences the different regenerative capacities after injury to peripheral or central axons remains largely unknown. To answer this question, we performed a single-cell transcriptional profiling of mouse DRG in response to peripheral (sciatic nerve crush) and central axon injuries (dorsal root crush and spinal cord injury). Each cell type responded differently to the three types of injuries. All injuries increased the proportion of a cell type that shares features of both immune cells and glial cells. A distinct subset of satellite glial cells (SGC) appeared specifically in response to peripheral nerve injury. Activation of the PPARα signaling pathway in SGC, which promotes axon regeneration after peripheral nerve injury, failed to occur after central axon injuries. Treatment with the FDA-approved PPARα agonist fenofibrate increased axon regeneration after dorsal root injury. This study provides a map of the distinct DRG microenvironment responses to peripheral and central injuries at the single-cell level and highlights that manipulating non-neuronal cells could lead to avenues to promote functional recovery after CNS injuries or disease.
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Affiliation(s)
- Oshri Avraham
- Department of Neuroscience, Washington University School of MedicineSaint LouisUnited States
| | - Rui Feng
- Department of Neuroscience, Washington University School of MedicineSaint LouisUnited States
| | - Eric Edward Ewan
- Department of Neuroscience, Washington University School of MedicineSaint LouisUnited States
| | - Justin Rustenhoven
- Department of Pathology and Immunology, Washington University School of MedicineSt LouisUnited States
- Center for Brain Immunology and Glia (BIG), Washington University School of MedicineSt LouisUnited States
| | - Guoyan Zhao
- Department of Neuroscience, Washington University School of MedicineSaint LouisUnited States
- Department of Pathology and Immunology, Washington University School of MedicineSt LouisUnited States
| | - Valeria Cavalli
- Department of Neuroscience, Washington University School of MedicineSaint LouisUnited States
- Center of Regenerative Medicine, Washington University School of MedicineSt. LouisUnited States
- Hope Center for Neurological Disorders, Washington University School of MedicineSt. LouisUnited States
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Alterations of Dopamine-Related Transcripts in A11 Diencephalospinal Pathways after Spinal Cord Injury. Neural Plast 2021; 2021:8838932. [PMID: 33510781 PMCID: PMC7822663 DOI: 10.1155/2021/8838932] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 12/04/2020] [Accepted: 01/05/2021] [Indexed: 12/15/2022] Open
Abstract
The diencephalic A11 nuclei are the primary source of spinal dopamine (DA). Neurons in this region project to all levels of the spinal cord. Traumatic spinal cord injury (SCI) often interrupts descending and ascending neuronal pathways and further elicits injury-induced neuronal plasticity. However, it is unknown how A11 neurons and projections respond to SCI-induced axotomy. Based on preliminary observation, we hypothesized that A11 DA-ergic neurons rostral to the lesion site might change their capacity to synthesize DA after SCI. Adult rats received a complete spinal cord transection at the 10th thoracic (T10) level. After 3 or 8 weeks, rostral (T5) and caudal (L1) spinal cord tissue was collected to measure mRNA levels of DA-related genes. Meanwhile, A11 neurons in the brain were explicitly isolated by laser capture microdissection, and single-cell qPCR was employed to evaluate mRNA levels in the soma. Histological analysis was conducted to assess the number of A11 DA-ergic neurons. The results showed that, compared to naïve rats, mRNA levels of tyrosine hydroxylase (TH), dopamine decarboxylase (DDC), and D2 receptors in the T5 spinal segment had a transient decrease and subsequent recovery. However, dopamine-β-hydroxylase (DBH), D1 receptors, and DA-associated transcription factors did not change following SCI. Furthermore, axon degeneration below the lesion substantially reduced mRNA levels of TH and D2 in the L1 spinal segment. However, DDC transcript underwent only a temporary decrease. Similar mRNA levels of DA-related enzymes were detected in the A11 neuronal soma between naïve and SCI rats. In addition, immunostaining revealed that the number of A11 DA neurons did not change after SCI, indicating a sustention of capacity to synthesize DA in the neuroplasm. Thus, impaired A11 diencephalospinal pathways following SCI may transiently reduce DA production in the spinal cord rostral to the lesion but not in the brain.
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Ewan EE, Avraham O, Carlin D, Gonçalves TM, Zhao G, Cavalli V. Ascending dorsal column sensory neurons respond to spinal cord injury and downregulate genes related to lipid metabolism. Sci Rep 2021; 11:374. [PMID: 33431991 PMCID: PMC7801468 DOI: 10.1038/s41598-020-79624-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 12/07/2020] [Indexed: 02/08/2023] Open
Abstract
Regeneration failure after spinal cord injury (SCI) results in part from the lack of a pro-regenerative response in injured neurons, but the response to SCI has not been examined specifically in injured sensory neurons. Using RNA sequencing of dorsal root ganglion, we determined that thoracic SCI elicits a transcriptional response distinct from sciatic nerve injury (SNI). Both SNI and SCI induced upregulation of ATF3 and Jun, yet this response failed to promote growth in sensory neurons after SCI. RNA sequencing of purified sensory neurons one and three days after injury revealed that unlike SNI, the SCI response is not sustained. Both SCI and SNI elicited the expression of ATF3 target genes, with very little overlap between conditions. Pathway analysis of differentially expressed ATF3 target genes revealed that fatty acid biosynthesis and terpenoid backbone synthesis were downregulated after SCI but not SNI. Pharmacologic inhibition of fatty acid synthase, the enzyme generating palmitic acid, decreased axon growth and regeneration in vitro. These results support the notion that decreased expression of lipid metabolism-related genes after SCI, including fatty acid synthase, may restrict axon regenerative capacity after SCI.
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Affiliation(s)
- Eric E Ewan
- Department of Neuroscience, Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8108, St. Louis, MO, 63110-1093, USA
| | - Oshri Avraham
- Department of Neuroscience, Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8108, St. Louis, MO, 63110-1093, USA
| | - Dan Carlin
- Department of Neuroscience, Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8108, St. Louis, MO, 63110-1093, USA
| | - Tassia Mangetti Gonçalves
- Department of Neuroscience, Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8108, St. Louis, MO, 63110-1093, USA
| | - Guoyan Zhao
- Department of Neuroscience, Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8108, St. Louis, MO, 63110-1093, USA
| | - Valeria Cavalli
- Department of Neuroscience, Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8108, St. Louis, MO, 63110-1093, USA. .,Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, 63110, USA. .,Center of Regenerative Medicine, Washington University School of Medicine, St. Louis, MO, 63110, USA.
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10
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El Waly B, Escarrat V, Perez-Sanchez J, Kaur J, Pelletier F, Collazos-Castro JE, Debarbieux F. Intravital Assessment of Cells Responses to Conducting Polymer-Coated Carbon Microfibres for Bridging Spinal Cord Injury. Cells 2021; 10:cells10010073. [PMID: 33466339 PMCID: PMC7824803 DOI: 10.3390/cells10010073] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 12/27/2020] [Accepted: 12/29/2020] [Indexed: 12/18/2022] Open
Abstract
The extension of the lesion following spinal cord injury (SCI) poses a major challenge for regenerating axons, which must grow across several centimetres of damaged tissue in the absence of ordered guidance cues. Biofunctionalized electroconducting microfibres (MFs) that provide biochemical signals, as well as electrical and mechanical cues, offer a promising therapeutic approach to help axons overcome this blind journey. We used poly(3,4-ethylenedioxythiophene)-coated carbon MFs functionalized with cell adhesion molecules and growth factors to bridge the spinal cord after a partial unilateral dorsal quadrant lesion (PUDQL) in mice and followed cellular responses by intravital two-photon (2P) imaging through a spinal glass window. Thy1-CFP//LysM-EGFP//CD11c-EYFP triple transgenic reporter animals allowed real time simultaneous monitoring of axons, myeloid cells and microglial cells in the vicinity of the implanted MFs. MF biocompatibility was confirmed by the absence of inflammatory storm after implantation. We found that the sprouting of sensory axons was significantly accelerated by the implantation of functionalized MFs after PUDQL. Their implantation produced better axon alignment compared to random and misrouted axon regeneration that occurred in the absence of MF, with a most striking effect occurring two months after injury. Importantly, we observed differences in the intensity and composition of the innate immune response in comparison to PUDQL-only animals. A significant decrease of immune cell density was found in MF-implanted mice one month after lesion along with a higher ratio of monocyte-derived dendritic cells whose differentiation was accelerated. Therefore, functionalized carbon MFs promote the beneficial immune responses required for neural tissue repair, providing an encouraging strategy for SCI management.
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Affiliation(s)
- Bilal El Waly
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and Centre National de la Recherche Scientifique, 13005 Marseille, France; (B.E.W.); (V.E.); (J.P.-S.); (J.K.); (F.P.)
- Centre Européen de Recherche en Imagerie Médicale, Aix-Marseille Université, 13005 Marseille, France
| | - Vincent Escarrat
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and Centre National de la Recherche Scientifique, 13005 Marseille, France; (B.E.W.); (V.E.); (J.P.-S.); (J.K.); (F.P.)
- Centre Européen de Recherche en Imagerie Médicale, Aix-Marseille Université, 13005 Marseille, France
| | - Jimena Perez-Sanchez
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and Centre National de la Recherche Scientifique, 13005 Marseille, France; (B.E.W.); (V.E.); (J.P.-S.); (J.K.); (F.P.)
- Centre Européen de Recherche en Imagerie Médicale, Aix-Marseille Université, 13005 Marseille, France
| | - Jaspreet Kaur
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and Centre National de la Recherche Scientifique, 13005 Marseille, France; (B.E.W.); (V.E.); (J.P.-S.); (J.K.); (F.P.)
- Centre Européen de Recherche en Imagerie Médicale, Aix-Marseille Université, 13005 Marseille, France
- Department of Neuroscience, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Florence Pelletier
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and Centre National de la Recherche Scientifique, 13005 Marseille, France; (B.E.W.); (V.E.); (J.P.-S.); (J.K.); (F.P.)
- Centre Européen de Recherche en Imagerie Médicale, Aix-Marseille Université, 13005 Marseille, France
| | - Jorge Eduardo Collazos-Castro
- Neural Repair and Biomaterials Laboratory, Hospital Nacional de Parapléjicos (SESCAM), 45071 Toledo, Spain
- Correspondence: (J.C.-C.); (F.D.); Tel.:+34-925-247758 (J.C.-C.); +33-491-324186 (F.D.)
| | - Franck Debarbieux
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and Centre National de la Recherche Scientifique, 13005 Marseille, France; (B.E.W.); (V.E.); (J.P.-S.); (J.K.); (F.P.)
- Centre Européen de Recherche en Imagerie Médicale, Aix-Marseille Université, 13005 Marseille, France
- Institut Universitaire de France, 75005 Paris, France
- Correspondence: (J.C.-C.); (F.D.); Tel.:+34-925-247758 (J.C.-C.); +33-491-324186 (F.D.)
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11
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Zhang N, Lin J, Chin JS, Zhang K, Chew SY. A laser microdissection-based axotomy model incorporating the use of biomimicking fiber scaffolds reveals that microRNAs promote axon regeneration over long injury distances. Biomater Sci 2020; 8:6286-6300. [PMID: 33020773 DOI: 10.1039/d0bm01380c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The regeneration of injured neurons over long injury distances remains suboptimal. In order to successfully stimulate nerve regrowth, potent biomolecules are necessary. Furthermore, reproducible and translatable methods to test the potency of candidate drugs for enhancing nerve regeneration over long axotomy distances are also needed. To address these issues, we report a novel laser microdissection-based axotomy model that involves the use of biomimicking aligned fiber substrates to precisely control neuronal axotomy distances. Correspondingly, we demonstrate that in the absence of therapeutics, dorsal root ganglion (DRG) explants (consisting of neurons) axotomized within short distances from the main cell somas regenerated significantly longer than axons that were injured more distally (p < 0.05). However, when treated with a cocktail of microRNAs (miR-132/miR-222/miR-431), robust neurite outgrowth was observed (p < 0.05). Specifically, microRNA treatment promoted neurite outgrowth by ∼2.2-fold as compared to untreated cells and this enhancement was more significant under the less conducive regeneration condition of a long axotomy distance (i.e. 1000 μm from the cell soma). Besides that, we demonstrated that the treatment of miR-132/miR-222/miR-431 led to a longer length of nerve regeneration as well as a bigger nerve extension area after sciatic nerve transection injury. These results indicate that distance effects on axonal regrowth may be overcome by the effects of microRNAs and that these microRNAs may serve as promising therapeutics for nerve injury treatment.
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Affiliation(s)
- Na Zhang
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459
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12
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Salvadores N, Court FA. The necroptosis pathway and its role in age-related neurodegenerative diseases: will it open up new therapeutic avenues in the next decade? Expert Opin Ther Targets 2020; 24:679-693. [PMID: 32310729 DOI: 10.1080/14728222.2020.1758668] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
INTRODUCTION Necroptosis is a programmed form of necrotic cell death. Growing evidence demonstrates that necroptosis contributes to cell demise in different pathological conditions including age-dependent neurodegenerative diseases (NDs). These findings open new avenues for understanding the mechanisms of neuronal loss in NDs, which might eventually translate into novel therapeutic interventions. AREAS COVERED We reviewed key aspects of necroptosis, in health and disease, focusing on evidence demonstrating its involvement in the pathogenesis of age-related NDs. We then highlight the activation of this pathway in the mechanism of axonal degeneration. We searched on PubMed the literature regarding necroptosis published between 2008 and 2020 and reviewed all publications were necroptosis was studied in the context of age-related NDs. EXPERT OPINION Axonal loss and neuronal death are the ultimate consequences of NDs that translate into disease phenotypes. Targeting degenerative mechanisms of the neuron appears as a strategy that might cover a wide range of diseases. Thus, the participation of necroptosis as a common mediator of neuronal demise emerges as a promising target for therapeutic intervention. Considering evidence demonstrating that necroptosis mediates axonal degeneration, we propose and discuss the potential of targeting necroptosis-mediated axonal destruction as a strategy to tackle NDs before neuronal loss occurs.
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Affiliation(s)
- Natalia Salvadores
- Faculty of Sciences, Center for Integrative Biology, Universidad Mayor , Santiago, Chile.,Fondap Geroscience Center for Brain Health and Metabolism , Santiago, Chile
| | - Felipe A Court
- Faculty of Sciences, Center for Integrative Biology, Universidad Mayor , Santiago, Chile.,Fondap Geroscience Center for Brain Health and Metabolism , Santiago, Chile
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13
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Borjini N, Paouri E, Tognatta R, Akassoglou K, Davalos D. Imaging the dynamic interactions between immune cells and the neurovascular interface in the spinal cord. Exp Neurol 2019; 322:113046. [PMID: 31472115 DOI: 10.1016/j.expneurol.2019.113046] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 08/16/2019] [Accepted: 08/27/2019] [Indexed: 12/19/2022]
Abstract
Imaging the dynamic interactions between immune cells, glia, neurons and the vasculature in living rodents has revolutionized our understanding of physiological and pathological mechanisms of the CNS. Emerging microscopy and imaging technologies have enabled longitudinal tracking of structural and functional changes in a plethora of different cell types in the brain. The development of novel methods also allowed stable and longitudinal optical access to the spinal cord with minimum tissue perturbation. These important advances facilitated the application of in vivo imaging using two-photon microscopy for studies of the healthy, diseased, or injured spinal cord. Indeed, decoding the interactions between peripheral and resident cells with the spinal cord vasculature has shed new light on neuroimmune and vascular mechanisms regulating the onset and progression of neurological diseases. This review focuses on imaging studies of the interactions between the vasculature and peripheral immune cells or microglia, with emphasis on their contribution to neuroinflammation. We also discuss in vivo imaging studies highlighting the importance of neurovascular changes following spinal cord injury. Real-time imaging of blood-brain barrier (BBB) permeability and other vascular changes, perivascular glial responses, and immune cell entry has revealed unanticipated cellular mechanisms and novel molecular pathways that can be targeted to protect the injured or diseased CNS. Imaging the cell-cell interactions between the vasculature, immune cells, and neurons as they occur in real time, is a powerful tool both for testing the efficacy of existing therapeutic approaches, and for identifying new targets for limiting damage or enhancing the potential for repair of the affected spinal cord tissue.
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Affiliation(s)
- Nozha Borjini
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Evi Paouri
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | | | - Katerina Akassoglou
- Gladstone Institutes, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Dimitrios Davalos
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA; Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH, USA.
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