Sorensen Annette, Moffat Keith, Thomson Christine, Barnett Susan C
Division of Clinical Neuroscience, University of Glasgow, Beatson Institute, Glasgow, United Kingdom.
Glia. 2008 May;56(7):750-63. doi: 10.1002/glia.20650.
We have examined the interaction between olfactory ensheathing cells (OECs), Schwann cells (SC), oligodendrocytes, and CNS axons using cultures generated from embryonic rat spinal cord. Oligodendrocyte process extension and myelination in these cultures was poor if the cells were plated on OECs or SCs. Myelin internodes and nodes of Ranvier formed frequently if these cultures were plated onto monolayers of neurosphere-derived astrocytes (NsAs). In the myelinated fibers generated on NsAs, Nav channels, caspr, and neurofascin molecules were correctly assembled at the nodes of Ranvier. The density of neurites, survival, and antigenic differentiation of oligodendrocytes was similar on OEC and NsAs monolayers. However, on OEC monolayers, despite a transient increase in the number of endogenous oligodendrocytes, there was a decrease in oligodendrocyte process extension and axonal ensheathment when compared with cultures plated on NsAs monolayers. To determine if these changes were due to axonal or glial factors, spinal cord oligodendrocytes were plated onto monolayers of OECs, NsAs, and poly-L-lysine in the absence of neurons. In these cultures, process extension and myelin-like membrane formation by oligodendrocytes was improved on monolayers of OEC. This suggests that inhibition of process extension is mediated via cross-talk between OECs and neurites. In cultures containing axons plated on OEC monolayers, oligodendrocyte process formation, axonal ensheathment, and myelination occurred albeit lower if the cultures were supplemented with NsAs conditioned medium. These data suggest OECs can permit neurite extension and oligodendrocyte proliferation, but lack secreted factor(s) and possible cell-cell contact that is necessary for oligodendrocyte process extension and myelination.
我们使用从胚胎大鼠脊髓生成的培养物，研究了嗅鞘细胞（OECs）、雪旺细胞（SCs）、少突胶质细胞和中枢神经系统轴突之间的相互作用。如果将细胞接种在OECs或SCs上，这些培养物中少突胶质细胞的突起延伸和髓鞘形成情况较差。如果将这些培养物接种到神经球衍生星形胶质细胞（NsAs）的单层上，则髓鞘节段和郎飞结会频繁形成。在NsAs上生成的有髓纤维中，Nav通道、接触蛋白相关蛋白（caspr）和神经束蛋白分子在郎飞结处正确组装。少突胶质细胞的神经突密度、存活率和抗原分化在OEC和NsAs单层上相似。然而，在OEC单层上，尽管内源性少突胶质细胞数量短暂增加，但与接种在NsAs单层上的培养物相比，少突胶质细胞的突起延伸和轴突包裹减少。为了确定这些变化是由于轴突还是胶质细胞因素引起的，在没有神经元的情况下，将脊髓少突胶质细胞接种到OECs、NsAs和聚-L-赖氨酸的单层上。在这些培养物中，少突胶质细胞在OEC单层上的突起延伸和髓鞘样膜形成得到改善。这表明突起延伸的抑制是通过OECs与神经突之间的相互作用介导的。在含有接种在OEC单层上的轴突的培养物中，如果用NsAs条件培养基补充培养物，少突胶质细胞的突起形成、轴突包裹和髓鞘形成会发生，尽管程度较低。这些数据表明，OECs可以允许神经突延伸和少突胶质细胞增殖，但缺乏少突胶质细胞突起延伸和髓鞘形成所需的分泌因子和可能的细胞间接触。
