Schwann cells genetically engineered to express PSA show enhanced migratory potential without impairment of their myelinating ability in vitro
Schwann cells genetically engineered to express PSA show enhanced migratory potential without impairment of their myelinating ability in vitro
复制标题
作者：
Lavdas, AA;Franceschini, I;Matsas, R
雪旺细胞是三叉神经节的髓鞘形成细胞，由于它们可以使中枢神经系统轴突重新髓鞘形成，因此是有吸引力的再髓鞘治疗的候选细胞。然而，它们在中枢神经系统组织中的整合似乎受到了阻碍，至少部分是因为它们在中枢神经系统环境中的有限运动性。由于多唾液酸(PSA)形式的NCAM调节神经前体在中枢神经系统的迁移，而在发育中的雪旺细胞中不表达，我们研究了给予出生后大鼠雪旺细胞持续表达PSA是否增强了它们的运动性。用编码聚唾液酸基转移酶STX的逆转录病毒转导细胞，STX是一种在NCAM上合成PSA的酶。用缝隙桥接法检测表达STX或标志基因碱性磷酸酶的野生型细胞和转导细胞在分离细胞中的迁移，以及在出生后脑片培养中移植细胞的迁移。与对照细胞相比，两种模型中表达PSA的细胞的迁移均显著增加，这种作用可被PSA的内源性尿氨酸酶-N去除而取消。PSA阳性的雪旺细胞在体外仍具有分化能力，并表达Krox20和P零髓鞘标记物。将转导STX基因的细胞移植到新生小脑切片中，2~3周后，可与对照细胞一样形成浦肯野细胞轴突，并形成髓鞘节间。在纯许旺细胞培养和切片共培养中，PSA在细胞膜上重新分布，并在分化过程中下调。因此，PNS髓鞘形成细胞在中枢神经系统内的迁移特性可以在不改变其分化程序的情况下得到增强。这一发现可能有助于髓鞘再生疗法的发展。(C)2006年Wiley-Liss，Inc.
Schwann cells, the myelin-forming cells of the PNS, are attractive candidates for remyelination therapy as they can remyelinate CNS axons. Yet their integration in CNS tissue appears hampered, at least in part, by their limited motility in the CNS environment. As the polysialylated (PSA) form of NCAM regulates migration of neural precursors in the CNS and is not expressed by developing Schwann cells, we investigated whether conferring sustained expression of PSA to Schwann cells derived from postnatal rats enhances their motility. Cells were transduced with a retrovirus encoding polysialyl-transferase STX, an enzyme that synthesizes PSA on NCAM. Migration of wild type and transduced cells expressing STX or the marker gene alkaline phosphatase was examined using a gap bridging assay in dissociated cells and by grafting cells in slice cultures of postnatal brain. Migration of PSA expressing cells was significantly increased in both models, as compared to control cells, and this effect was abolished by endoneuraminidase-N stripping of PSA. PSA-positive Schwann cells retained the ability to differentiate in vitro and expressed the Krox20 and P zero myelination markers. When grafted in neonatal cerebellar slices, STX-transduced cells started to myelinate Purkinje cell axons like control cells and make myelin internodes after 2 to 3 weeks. PSA was redistributed on the cell membrane and downregulated during differentiation in pure Schwann cell cultures and slice co-cultures. Thus, migratory properties of PNS myelin-forming cells within the CNS can be enhanced without altering their differentiation program. This finding may be beneficial for the development of remyelination therapies. (c) 2006 Wiley-Liss, Inc.