1
|
Dendrite regeneration in the vertebrate spinal cord. Dev Biol 2022; 488:114-119. [PMID: 35644253 PMCID: PMC10046145 DOI: 10.1016/j.ydbio.2022.05.014] [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: 04/12/2022] [Revised: 05/18/2022] [Accepted: 05/22/2022] [Indexed: 11/20/2022]
Abstract
Axon regeneration in response to injury has been documented in many animals over several hundred years. In contrast, how neurons respond to dendrite injury has been examined only in the last decade. So far, dendrite regeneration after injury has been documented in invertebrate model systems, but has not been assayed in a vertebrate. In this study, we use zebrafish motor neurons to track neurons after dendrite injury. We address two major gaps in our knowledge of dendrite regeneration: 1) whether post-synaptic dendrites can regenerate and 2) whether vertebrate dendrites can regenerate. We find that motor neurons survive laser microsurgery to remove one or all dendrites. Outgrowth of new dendrites typically initiated one to three days after injury, and a new, stable dendrite arbor was in place by five days after injury. We conclude that zebrafish motor neurons have the capacity to regenerate a new dendrite arbor.
Collapse
|
2
|
Deng J, Xie H, Chen Y, Peng Z, Zhao J, Zhou Y, Chen C, Zhang K. Comparative study of the reorganization in bilateral motor and sensory cortices after spinal cord hemisection in mice. Neuroreport 2021; 32:1082-1090. [PMID: 34173791 DOI: 10.1097/wnr.0000000000001694] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The effects of spinal cord injury (SCI) on sensorimotor cortex plasticity have not been well studied. Therefore, to explore the reorganization after SCI, we dynamically monitored postsynaptic dendritic spines of pyramidal neurons in vivo. METHODS Thy1-YFP transgenic mice were randomly divided into two groups: the control and SCI group. We then opened the spinal vertebral plates of all mice and sectioned one-half of the spinal cord in SCI group. The relevant areas were imaged bilaterally at 0, 3, 14 and 28 days post-SCI. The rates of elimination, formation and stable spines were evaluated. RESULTS At the early stage, the rate of stable and elimination spines experienced a similar change trend. But the rate of formation spines in the contralateral sensory cortex was significantly increased after SCI compared with those in the control group. At the late stage, spines of three types remodeled very differently between the sensory and motor cortex. Compared with those in the control group, spines in the bilateral sensory cortex demonstrated obvious differences in the rate of stable and elimination spines but not formation spines, while spines in the motor cortex, especially in the contralateral cortex increased significantly in the rate of formation after SCI. As for survival rate, differences mainly appeared in time frame instead of cortex type or region. CONCLUSIONS The dendritic spines in hindlimb representation area of the sensorimotor cortex experienced bilaterally remodeling after SCI. And those spines in the sensory and motor cortex experienced great but different change trends after SCI.
Collapse
Affiliation(s)
| | - Huimin Xie
- Department of Plastic and Reconstructive surgery, General Hospital of Chinese PLA
| | - Youbai Chen
- Department of Anesthesiology, District Hospital of Shun Yi, Beijing
| | | | - Jiajia Zhao
- Department of Anesthesiology, District Hospital of Shun Yi, Beijing
| | - Yanmei Zhou
- Department of Neuroscience, Shenzhen Bay Laboratory, Shenzhen
| | | | - Kexue Zhang
- Department of Pediatric Surgery, General Hospital of Chinese PLA, Beijing, People's Republic of China
| |
Collapse
|
3
|
Yu Z, Li W, Lan J, Hayakawa K, Ji X, Lo EH, Wang X. EphrinB2-EphB2 signaling for dendrite protection after neuronal ischemia in vivo and oxygen-glucose deprivation in vitro. J Cereb Blood Flow Metab 2021; 41:1744-1755. [PMID: 33325764 PMCID: PMC8221775 DOI: 10.1177/0271678x20973119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
In order to rescue neuronal function, neuroprotection should be required not only for the neuron soma but also the dendrites. Here, we propose the hypothesis that ephrin-B2-EphB2 signaling may be involved in dendritic degeneration after ischemic injury. A mouse model of focal cerebral ischemia with middle cerebral artery occlusion (MCAO) method was used for EphB2 signaling test in vivo. Primary cortical neuron culture and oxygen-glucose deprivation were used to assess EphB2 signaling in vitro. siRNA and soluble ephrin-B2 ectodomain were used to block ephrin-B2-Ephb2 signaling. In the mouse model of focal cerebral ischemia and in neurons subjected to oxygen-glucose deprivation, clustering of ephrin-B2 with its receptor EphB2 was detected. Phosphorylation of EphB2 suggested activation of this signaling pathway. RNA silencing of EphB2 prevented neuronal death and preserved dendritic length. To assess therapeutic potential, we compared the soluble EphB2 ectodomain with the NMDA antagonist MK801 in neurons after oxygen-glucose deprivation. Both agents equally reduced lactate dehydrogenase release as a general marker of neurotoxicity. However, only soluble EphB2 ectodomain protected the dendrites. These findings provide a proof of concept that ephrin-B2-EphB2 signaling may represent a novel therapeutic target to protect both the neuron soma as well as dendrites against ischemic injury.
Collapse
Affiliation(s)
- Zhanyang Yu
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Wenlu Li
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Jing Lan
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China.,Cerebrovascular Research Institute, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Kazuhide Hayakawa
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Xunming Ji
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China.,Cerebrovascular Research Institute, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Eng H Lo
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Xiaoying Wang
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.,Clinical Neuroscience Research Center, Department of Neurosurgery, Tulane University School of Medicine, New Orleans, LA, USA
| |
Collapse
|
4
|
Agostinone J, Alarcon-Martinez L, Gamlin C, Yu WQ, Wong ROL, Di Polo A. Insulin signalling promotes dendrite and synapse regeneration and restores circuit function after axonal injury. Brain 2019; 141:1963-1980. [PMID: 29931057 PMCID: PMC6022605 DOI: 10.1093/brain/awy142] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 04/06/2018] [Indexed: 01/07/2023] Open
Abstract
Dendrite pathology and synapse disassembly are critical features of chronic neurodegenerative diseases. In spite of this, the capacity of injured neurons to regenerate dendrites has been largely ignored. Here, we show that, upon axonal injury, retinal ganglion cells undergo rapid dendritic retraction and massive synapse loss that preceded neuronal death. Human recombinant insulin, administered as eye drops or systemically after dendritic arbour shrinkage and prior to cell loss, promoted robust regeneration of dendrites and successful reconnection with presynaptic targets. Insulin-mediated regeneration of excitatory postsynaptic sites on retinal ganglion cell dendritic processes increased neuronal survival and rescued light-triggered retinal responses. Further, we show that axotomy-induced dendrite retraction triggered substantial loss of the mammalian target of rapamycin (mTOR) activity exclusively in retinal ganglion cells, and that insulin fully reversed this response. Targeted loss-of-function experiments revealed that insulin-dependent activation of mTOR complex 1 (mTORC1) is required for new dendritic branching to restore arbour complexity, while complex 2 (mTORC2) drives dendritic process extension thus re-establishing field area. Our findings demonstrate that neurons in the mammalian central nervous system have the intrinsic capacity to regenerate dendrites and synapses after injury, and provide a strong rationale for the use of insulin and/or its analogues as pro-regenerative therapeutics for intractable neurodegenerative diseases including glaucoma.
Collapse
Affiliation(s)
- Jessica Agostinone
- Department of Neuroscience, University of Montreal, Montreal, Quebec, Canada.,University of Montreal Hospital Research Center (CR-CHUM), University of Montreal, Montreal, Quebec, Canada
| | - Luis Alarcon-Martinez
- Department of Neuroscience, University of Montreal, Montreal, Quebec, Canada.,University of Montreal Hospital Research Center (CR-CHUM), University of Montreal, Montreal, Quebec, Canada
| | - Clare Gamlin
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, Washington, USA
| | - Wan-Qing Yu
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, Washington, USA
| | - Rachel O L Wong
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, Washington, USA
| | - Adriana Di Polo
- Department of Neuroscience, University of Montreal, Montreal, Quebec, Canada.,University of Montreal Hospital Research Center (CR-CHUM), University of Montreal, Montreal, Quebec, Canada
| |
Collapse
|
5
|
Peterson SL, Benowitz LI. Mammalian dendritic regrowth: a new perspective on neural repair. Brain 2018; 141:1891-1894. [PMID: 30053179 DOI: 10.1093/brain/awy165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Sheri L Peterson
- Boston Children's Hospital, Harvard Medical School, Department of Neurosurgery, Boston, Massachusetts, USA
| | - Larry I Benowitz
- Boston Children's Hospital, Harvard Medical School, Department of Neurosurgery, Boston, Massachusetts, USA
| |
Collapse
|