Targeting of hematopoietic stem cells to the CNS and differentiation into glia and neurons

最近的研究表明，骨髓来源的细胞可以通过血脑屏障迁移到中枢神经系统(CNS)，并分化为小胶质细胞、星形胶质细胞和可能的神经元。这些报告表明，造血干细胞可能被用来取代神经变性后丢失的脑细胞，第二，作为一种天然的载体，通过血脑屏障迁移到中枢神经系统。该项目将评估基因工程造血干细胞在小鼠体内的迁移和分化。用流式细胞术从肌动蛋白启动子启动子作用下表达绿色荧光蛋白(GFP)的小鼠体内分离出的造血干细胞(LIN-、c-KIT+、SCA-1+)，将在神经分化因子(如：成纤维细胞生长因子-2、表皮生长因子)的短期刺激下，经逆转录病毒转导表达趋化因子受体(如：CX3CR1)，以结合中枢神经系统来源的趋化因子。然后，GFP标记的细胞将被静脉注射到小鼠体内，然后在脑组织中通过免疫组织化学、流式细胞仪和电生理学进行分析。如果成功，这项技术将提供一种方法，将造血干细胞靶向中枢神经系统，并可能在包括神经胶质细胞和神经元在内的常驻脑细胞中分化。

Recent studies demonstrate the migration of bone marrow derived cells into the central nervous system (CNS) past the blood-brain barrier and their differentiation into microglia, astrocytes and possibly neurons. These reports suggest the possibility that hematopoietic stem cells may be used, first, to replace brain cells lost following neurodegeneration and, second, as a natural vehicle to migrate through the blood-brain barrier into the CNS. This project will assess the migration and differentiation of genetically engineered hematopoietic stem cells in mice. Hematopoietic stem cells (lin-, c-kit+, sca-1+), isolated by flow cytometry from mice expressing green fluorescenent protein (GFP) under the ß-actin promotor, will be primed for a short time period with neural differentiation factors (e.g. FGF-2, EGF) and retrovirally transduced to express chemokine receptors (e.g. CX3CR1), which bind CNS-derived chemokines. The GFP-marked cells will then be applied intravenously into mice and later analyzed in the brain tissue by immunohistochemistry, flow cytometry and electrophysiology. If successful, this technique will provide a method for targeting of hematopoietic stem cells to the CNS and their possible differentiation in resident brain cells including glial cells and neurons.