MACROPHAGES/MICROGLIA AND CSPGS IN SPINAL CORD INJURY

超过25万美国人因急性脊髓损伤（SCI）而严重和永久残疾。 目前没有促进SCI慢性期神经功能恢复的疗法。 拟议的研究将测试中心假设，即巨噬细胞/小胶质细胞表达基质分子，抑制脊髓损伤后轴突生长，这些假定的抑制分子的阻断将增加轴突再生。 为了挑战这一假设，将提出以下具体目的：1）使用原位杂交和免疫标记确定CSPG蛋白聚糖表达的细胞来源，以及通过应用蛋白聚糖抑制剂β-D-木糖苷抑制蛋白聚糖合成是否增强SCI后轴突生长; 2）使用半定量PCR确定经生长因子和细胞因子处理的巨噬细胞是否在体外调节其CSPGs的表达;和3）确定经遗传修饰以表达和分泌增加量的抑制性细胞因子（例如，白细胞介素10或目的2中鉴定的其他物质）将减少ECM分子的沉积并促进SCI后的轴突修复。 在这里，将使用转基因细胞递送、免疫标记、原位杂交和神经解剖追踪。

Over 250,000 Americans are severely and permanently disabled due to acute spinal cord injuries (SCI). There currently is no therapy for promoting recovery of neurological function in chronic stages of SCI. The proposed study will test the central hypothesis that macrophages/microglia express matrix molecules that inhibit axonal outgrowth after SCI, and that the blockade of these putative inhibitory molecules will augment axonal regeneration. To challenge this hypothesis, the following Specific Aims will be addressed: 1) Determine the cellular source of CSPG proteoglycan expression using in situ hybridization and immunolabelling, and whether the inhibition of proteoglycan synthesis by application of the proteoglycan inhibitor beta-D- xyloside enhances axonal outgrowth after SCI; 2) Determine using semi-quantitative PCR whether macrophages treated with growth factors and cytokines modulate their expression of CSPGs in vitro; and 3) Determine whether grafts of fibroblasts genetically modified to express and secrete augmented amounts of inhibitory cytokines (e.g., interleukin 10 or other substances identified in Aims 2) will reduce the deposition of ECM molecules and promote axonal repair after SCI. Here, transgenic cellular delivery, immunolabeling, in situ hybridization and neuroanatomical tracing will be used.