Large-Scale Chondroitin Sulfate Proteoglycan Digestion with Chondroitinase Gene Therapy Leads to Reduced Pathology and Modulates Macrophage Phenotype following Spinal Cord Contusion Injury
Large-Scale Chondroitin Sulfate Proteoglycan Digestion with Chondroitinase Gene Therapy Leads to Reduced Pathology and Modulates Macrophage Phenotype following Spinal Cord Contusion Injury
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DOI：
10.1523/jneurosci.4369-13.2014
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发表时间：
2014-04-02
影响因子：
5.3
通讯作者：
Bradbury, Elizabeth J.
中科院分区：
文献类型：
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作者：
Bartus, Katalin;James, Nicholas D.;Bradbury, Elizabeth J.
硫酸软骨素蛋白聚糖（CSPG）抑制脊髓损伤后的修复。在这里，我们使用通过慢病毒载体（LV-ChABC）递送的与大肠杆菌相容的工程化软骨素酶ABC（ChABC）来探索大规模CSPG消化对脊髓修复的后果。我们证明了脊髓挫伤和LV-ChABC治疗后成年大鼠继发性损伤病理学显著降低，与对照组（LV-GFP）治疗动物相比，损伤后12周脊髓神经元和轴突的空化减少和保护增强。为了了解这些神经保护作用，我们研究了LV-ChABC治疗后的早期炎症变化。在损伤后3天，吞噬巨噬细胞标志物CD 68的表达增加，随后在2周时CD 206的表达增加，表明大规模CSPG消化可以改变巨噬细胞表型，以有利于交替激活的M2巨噬细胞。因此，ChABC治疗在体外诱导的非极化的单核细胞刺激脊髓损伤的组织外植体的条件培养基中的CD 206的表达显着增加。LV-ChABC还促进了特定CSPG的重塑以及增强的血管分布，这与CD 206阳性巨噬细胞密切相关。LV-ChABC的神经保护作用与感觉运动功能的改善相对应，早在损伤后1周就很明显，这是一个神经元存活增加与凋亡减少相关的时间点。功能改善一直维持到慢性损伤阶段，其中还观察到轴突传导改善和5-羟色胺能神经支配增加。因此，我们证明ChABC基因治疗可以调节继发性损伤过程，具有神经保护作用，导致长期改善的功能结果，并揭示了新的机制证据，即巨噬细胞表型的调节可能是这些作用的基础。
Chondroitin sulfate proteoglycans (CSPGs) inhibit repair following spinal cord injury. Here we use mammalian-compatible engineered chondroitinase ABC (ChABC) delivered via lentiviral vector (LV-ChABC) to explore the consequences of large-scale CSPG digestion for spinal cord repair. We demonstrate significantly reduced secondary injury pathology in adult rats following spinal contusion injury and LV-ChABC treatment, with reduced cavitation and enhanced preservation of spinal neurons and axons at 12 weeks postinjury, compared with control (LV-GFP)-treated animals. To understand these neuroprotective effects, we investigated early inflammatory changes following LV-ChABC treatment. Increased expression of the phagocytic macrophage marker CD68 at 3 d postinjury was followed by increased CD206 expression at 2 weeks, indicating that large-scale CSPG digestion can alter macrophage phenotype to favor alternatively activated M2 macrophages. Accordingly, ChABC treatment in vitro induced a significant increase in CD206 expression in unpolarized monocytes stimulated with conditioned medium from spinal-injured tissue explants. LV-ChABC also promoted the remodelling of specific CSPGs as well as enhanced vascularity, which was closely associated with CD206-positive macrophages. Neuroprotective effects of LV-ChABC corresponded with improved sensorimotor function, evident as early as 1 week postinjury, a time point when increased neuronal survival correlated with reduced apoptosis. Improved function was maintained into chronic injury stages, where improved axonal conduction and increased serotonergic innervation were also observed. Thus, we demonstrate that ChABC gene therapy can modulate secondary injury processes, with neuroprotective effects that lead to long-term improved functional outcome and reveal novel mechanistic evidence that modulation of macrophage phenotype may underlie these effects.