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Charsar BA, Brinton MA, Locke K, Chen AY, Ghosh B, Urban MW, Komaravolu S, Krishnamurthy K, Smit R, Pasinelli P, Wright MC, Smith GM, Lepore AC. AAV2-BDNF promotes respiratory axon plasticity and recovery of diaphragm function following spinal cord injury. FASEB J 2019; 33:13775-13793. [PMID: 31577916 DOI: 10.1096/fj.201901730r] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
More than half of spinal cord injury (SCI) cases occur in the cervical region, leading to respiratory dysfunction due to damaged neural circuitry that controls critically important muscles such as the diaphragm. The C3-C5 spinal cord is the location of phrenic motor neurons (PhMNs) that are responsible for diaphragm activation; PhMNs receive bulbospinal excitatory drive predominately from supraspinal neurons of the rostral ventral respiratory group (rVRG). Cervical SCI results in rVRG axon damage, PhMN denervation, and consequent partial-to-complete paralysis of hemidiaphragm. In a rat model of C2 hemisection SCI, we expressed the axon guidance molecule, brain-derived neurotrophic factor (BDNF), selectively at the location of PhMNs (ipsilateral to lesion) to promote directed growth of rVRG axons toward PhMN targets by performing intraspinal injections of adeno-associated virus serotype 2 (AAV2)-BDNF vector. AAV2-BDNF promoted significant functional diaphragm recovery, as assessed by in vivo electromyography. Within the PhMN pool ipsilateral to injury, AAV2-BDNF robustly increased sprouting of both spared contralateral-originating rVRG axons and serotonergic fibers. Furthermore, AAV2-BDNF significantly increased numbers of putative monosynaptic connections between PhMNs and these sprouting rVRG and serotonergic axons. These findings show that targeting circuit plasticity mechanisms involving the enhancement of synaptic inputs from spared axon populations is a powerful strategy for restoring respiratory function post-SCI.-Charsar, B. A., Brinton, M. A., Locke, K., Chen, A. Y., Ghosh, B., Urban, M. W., Komaravolu, S., Krishnamurthy, K., Smit, R., Pasinelli, P., Wright, M. C., Smith, G. M., Lepore, A. C. AAV2-BDNF promotes respiratory axon plasticity and recovery of diaphragm function following spinal cord injury.
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Affiliation(s)
- Brittany A Charsar
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Michael A Brinton
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Katherine Locke
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Anna Y Chen
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Biswarup Ghosh
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Mark W Urban
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Sreeya Komaravolu
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Karthik Krishnamurthy
- Department of Neuroscience, Jefferson Weinberg Amyotrophic Lateral Sclerosis (ALS) Center, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Rupert Smit
- Department of Anatomy and Cell Biology, Department of Neuroscience, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Piera Pasinelli
- Department of Neuroscience, Jefferson Weinberg Amyotrophic Lateral Sclerosis (ALS) Center, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Megan C Wright
- Department of Biology, Arcadia University, Philadelphia, Pennsylvania, USA
| | - George M Smith
- Department of Anatomy and Cell Biology, Department of Neuroscience, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Angelo C Lepore
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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Ohne H, Takahashi M, Satomi K, Hasegawa A, Takeuchi T, Sato S, Ichimura S. Mechanism of forelimb motor function restoration in rats with cervical spinal cord hemisection-neuroanatomical validation. IBRO Rep 2019; 7:10-25. [PMID: 31431931 PMCID: PMC6581651 DOI: 10.1016/j.ibror.2019.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 05/05/2019] [Indexed: 11/13/2022] Open
Abstract
Purpose The purpose of this study is neuroanatomical validation of forelimb motor function restoration in rats with cervical spinal cord injury. Materials and methods We used eight cervical hemisected rats and eight normal rats. We cut in half the C3/4 cervical spinal cord of 18-weeks-old normal rats. We used 24-weeks-old rats that had reached a nearly steady state of forelimb motor function after the hemisection (Hemisection group). Normal 24-week-old rats were used as Control group. To evaluate the corticospinal tracts, neuro-tracing by biotynirated dextran-amine (BDA) was used. BDA was injected into the damaged side of the cerebral primary motor cortex. In order to quantitatively analyze the specimen, we recorded a site where nerve fibers appear in each specimen in the image analysis (1) and defined the increase rate of immunostaining area using ImageJ in the image analysis (2). Based on the evaluation in the image analysis (1) and the image analysis (2), the Hemisection group and the Control group were compared. Results In the image analysis (1), a region with robust appearance of aberrant nerve fibers was observed in the cephalad side of the Hemisection site in Hemisection group than Control group. In the spinal cord caudal to the hemisection, such region was generally more in Hemisection group, however, disappeared or reduced appearance was observed in some regions. In the image analysis (2), no statistical significant difference was noted in each level. Conclusion There is a high probability that these aberrant nerve fibers beyond the midline could be involved in forelimb motor function restoration in rats with cervical cord hemisection.
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Affiliation(s)
- Hideaki Ohne
- Department of Orthopaedic Surgery, Kyorin University School of Medicine, 6-20-2 Shinkawa Mitaka, Tokyo, 181-8611, Japan
| | - Masahito Takahashi
- Department of Orthopaedic Surgery, Kyorin University School of Medicine, 6-20-2 Shinkawa Mitaka, Tokyo, 181-8611, Japan
| | - Kazuhiko Satomi
- Orthopaedic Surgery, Kugayama Hospital, 2-14-20 Kitakarasuyama Setagaya, Tokyo, 157-0061, Japan
| | - Atsushi Hasegawa
- Department of Orthopaedic Surgery, Kyorin University School of Medicine, 6-20-2 Shinkawa Mitaka, Tokyo, 181-8611, Japan
| | - Takumi Takeuchi
- Department of Orthopaedic Surgery, Kyorin University School of Medicine, 6-20-2 Shinkawa Mitaka, Tokyo, 181-8611, Japan
| | - Shunsuke Sato
- Department of Orthopaedic Surgery, Kyorin University School of Medicine, 6-20-2 Shinkawa Mitaka, Tokyo, 181-8611, Japan
| | - Shoichi Ichimura
- Department of Orthopaedic Surgery, Kyorin University School of Medicine, 6-20-2 Shinkawa Mitaka, Tokyo, 181-8611, Japan
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