| 제목 |
Nogo-A-targeting antibody protects against axonal degeneration after traumatic brain injury in mice |
| 소속 |
TBI Rehabilitation Center, National Traffic Injury Rehabilitation Hospital1, Seoul National University Hospital, Department of Rehabilitation Medicine2, National Traffic Injury Rehabilitation Hospital, National Traffic Injury Rehabilitation Research Institute3, Yonsei University College of Medicine, Department of Medicine4, Seoul National University College of Medicine, Department of Rehabilitation Medicine5, Seoul National University, Institute on Aging6, Seoul National University College of Medicine, Neuroscience Research Institute7 |
| 저자 |
Hoo Young Lee1,2*, Jinju Lee2, Jiyoung Jeon2, Byung-Mo Oh2,3† |
| 사사 |
This study was supported by grants from the MOLIT Research Fund (No. 0720205039). |
Object—Considering that axonal injury is one of the most common pathologies of traumatic brain injury (TBI), axonal regeneration is an attractive target for treatment. Axonal regeneration is partly inhibited by myelin-associated inhibitors (MAIs). One of the MAIs, Nogo-A, inhibits neurite outgrowth In vitro, and inhibition of Nogo-A In vivo enhanced axonal outgrowth and sprouting. However, the effect of pharmacologic neutralization of the Nogo-A on neurobehavioral outcome in preclinical models of TBI remains unclear. Here we investigated the effect of anti–Nogo-A monoclonal antibody 11C7 administration on the neurobehavioral outcome, histological and molecular responses following TBI in mice.
Methods— Male C57BL/6 mice were subjected to either controlled cortical impact (CCI) of moderate severity (impact parameters: velocity: 4.5 m/s, depth: 2 mm, dwell time: 200 ms) or sham injury (craniotomy only). Beginning 24 h post-injury, mAb 11C7 (n=10, 7 mg/ml) or control Ab (IgG) (n=11) was infused at a rate of 0.25 μl/h over 14 days into the contralateral ventricle using osmotic minipumps connected to an implanted cannula. 2 weeks post-injury, Neurological Severity Scale, rotarod test, and open field test were performed to assess neurological function, motor function, and anxiety, respectively. The expression levels of neuronal axon regeneration-related proteins (GAP-43, MBP) in the cortex and hippocampal region of the mice were determined by real-time polymerase chain reaction and western blot. Simultaneously, histological evaluation on axonal regeneration was observed by Bielschowsky silver and immunohistochemical staining and detected by the optical density (OD) method.
Results—The brain-injured animals treated with anti–Nogo-A monoclonal antibody 11C7 showed improvement in motor function (p < 0.05) at 2 weeks postinjury but no improvement in neurological severity nor anxiety compared with IgG-treated controls. Furthermore, Bielschowsky’s staining revealed a severe reduction in axon density, numerus axonal spheroids and varicosities, and swollen axons in IgG treated mice while anti–Nogo-A monoclonal antibody 11C7 treated mice showed moderate reduction in axon density and less swollen or varicose axons in cortex. However, the expression of GAP-43 and MBP did not show significant difference between anti–Nogo-A monoclonal antibody 11C7 and IgG-treated mice. The OD of the silver staining increased in the medial cortex of mAb 11C7-administrated mice compared with controls, but it did not show significant difference.
Conclusions—The full biochemical nature of limiting myelin-based inhibition in preclinical model of TBI remains elusive, and no single preclinical model of TBI will translate to all human TBI pathobiology. Nevertheless, these results raise the question of whether anti–Nogo-A monoclonal antibody 11C7 plays a protective role in axonal injury and is expected to be a potential therapeutic target for motor recovery following TBI. |
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Figure 1. A. Experimental design for Nogo-A-targeting antibody treatment after traumatic brain injury (A) A schematic time schedule for the experiment. Mice of 6-8 weeks of age were randomly assigned to experimental, control, or sham group. Beginning 24 h post- controlled cortical impact (CCI), mAb 11C7 or control Ab (IgG) was infused over 14 days into the contralateral ventricle using osmotic minipumps. 2 weeks post-injury, behavioral tests were performed. Then, brain tissues were harvested for histological and molecular analysis. B. Preclinical mouse model of CCI. C. Schema depicts the site of CCI lesion and osmotic pump implantation.
Figure 2. The effect of anti–Nogo-A monoclonal antibody 11C7 administration after CCI on (A) bodyweight, (B) neurological severity score, (C) rotarod test, and (D) openfield test. After 2 weeks of anti–Nogo-A monoclonal antibody 11C7 treatment, motor function recovered while the control mice showed significant motor deficit during 2 weeks of administration of IgG.
Figure 3. Axonal pathology by light microscopy under Bielschowsky silver stain (A) a sham subject with normal distribution and density of axons. (B) a control subject with focal cortical contusion exhibiting a severe reduction in axon density, numerus axonal spheroids and varicosities, and swollen axons (arrows) in corpus callosum and subcortex. (C) an anti-Nogo-A treated subject with focal cortical contusion with moderate reduction in axon density (arrows) than the control subject: scale X400
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