Sussman C R, Dyer K L, Marchionni M, Miller R H
Department of Neurosciences, Case Western Reserve University, Cleveland, Ohio 44106-4975, USA.
J Neurosci Res. 2000 Feb 1;59(3):413-20. doi: 10.1002/(SICI)1097-4547(20000201)59:3<413::AID-JNR16>3.0.CO;2-G.
The earliest oligodendrocyte precursors have been proposed to arise in the ventral ventricular zone of the embryonic thoraco-lumbar spinal cord and subsequently migrate to populate dorsal spinal cord. Using the expression of O4 immunoreactivity to define cells of the oligodendrocyte lineage, the development of oligodendrocytes in different regions of the mouse spinal cord was assayed. Consistent with earlier studies in other species, isolated explants of E11 ventral but not dorsal mouse spinal cord developed oligodendrocytes after 7 days in vitro. In contrast, in cultures derived from E13 embryos O4(+) oligodendrocytes developed in both ventral and dorsal cultures after 5 days in vitro. These data are consistent with a ventral to dorsal migration of committed oligodendrocyte progenitors occurring between E11 and E13. Although isolated early embryonic dorsal spinal cord does not give rise to oligodendrocytes in short term cultures, in long term cultures O4(+) cells develop in a subset of dorsal explants. After 10 days in vitro approximately 25% of both cervical and thoraco-lumbar E11 derived dorsal explants contained significant numbers of O4(+) cells. The molecular requirements for the dorsally-derived oligodendrocytes was similar to that in ventral cord. The appearance of O4(+) cells was dependent on sonic hedgehog and enhanced by neuregulin. These data suggest that early embryonic dorsal mouse spinal cord has an independent potential to generate oligodendrocytes under appropriate conditions. Whether this potential is realized during normal spinal cord development is currently unknown.
最早的少突胶质细胞前体被认为起源于胚胎胸腰段脊髓的腹侧脑室区，随后迁移至背侧脊髓定居。利用O4免疫反应性的表达来定义少突胶质细胞系的细胞，对小鼠脊髓不同区域少突胶质细胞的发育进行了检测。与其他物种早期的研究一致，E11小鼠腹侧而非背侧脊髓的分离外植体在体外培养7天后发育出少突胶质细胞。相比之下，在源自E13胚胎的培养物中，O4(+)少突胶质细胞在体外培养5天后在腹侧和背侧培养物中均有发育。这些数据与定向少突胶质细胞祖细胞在E11和E13之间从腹侧向背侧迁移的情况一致。虽然分离的早期胚胎背侧脊髓在短期培养中不会产生少突胶质细胞，但在长期培养中，O4(+)细胞在一部分背侧外植体中发育。体外培养10天后，源自E11的颈段和胸腰段背侧外植体中约25%含有大量O4(+)细胞。背侧来源的少突胶质细胞的分子需求与腹侧脊髓相似。O4(+)细胞的出现依赖于音猬因子，并受到神经调节蛋白的增强。这些数据表明，早期胚胎小鼠背侧脊髓在适当条件下具有独立产生少突胶质细胞的潜力。这种潜力在正常脊髓发育过程中是否得以实现目前尚不清楚。
